(19)
(11)EP 3 473 205 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
04.11.2020 Bulletin 2020/45

(21)Application number: 18212520.3

(22)Date of filing:  10.05.2013
(51)International Patent Classification (IPC): 
A61C 5/00(2017.01)

(54)

DENTAL DEVICE COMPRISING A MULTI-LAYER FILM WITH IMPROVED MODULUS PROPERTIES

ZAHNÄRZTLICHE VORRICHTUNG ENTHALTEND EINE MEHRSCHICHTFOLIE MIT VERBESSERTEN MODULUSEIGENSCHAFTEN

DISPOSITIF DENTAIRE COMPRENANT UN FILM MULTICOUCHES PRÉSENTANT DE MEILLEURES PROPRIÉTÉS DE MODULE


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 14.05.2012 US 3774512

(43)Date of publication of application:
24.04.2019 Bulletin 2019/17

(62)Application number of the earlier application in accordance with Art. 76 EPC:
13721759.2 / 2850126

(73)Proprietor: Align Technology, Inc.
San Jose, CA 95134 (US)

(72)Inventors:
  • PUDLEINER, Heinz
    47800 Krefeld (DE)
  • MEYER, Klaus
    41539 Dormagen (DE)
  • WINKLER, Jürgen
    40764 Langenfeld (DE)
  • BRÄUER, Wolfgang
    51375 Leverkusen (DE)
  • NICKEL, Jörg
    41539 Dormagen (DE)
  • PEHLERT, Craig
    Lenox, MA 01240 (US)
  • LI, Chunhua
    Cupertino, CA 95014 (US)
  • CHEN, Yan
    Cupertino, CA 95014 (US)

(74)Representative: Hodge, Emma Jane 
Brookes IP Windsor House 6-10 Mount Ephraim Road
Tunbridge Wells, Kent TN1 1EE
Tunbridge Wells, Kent TN1 1EE (GB)


(56)References cited: : 
DE-A1-102004 014 023
US-A1- 2004 146 670
DE-A1-102010 009 230
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description


    [0001] The invention relates to a dental device comprising a multi-layer, preferably co-extruded, plastic film with improved modulus properties, which is ; obtainable by a thermo-forming process.

    BACKGROUND OF THE INVENTION



    [0002] For several applications, in particular medical applications, it is of major interest that three-dimensionally formed articles, which have been obtained by forming a plastic film, are stable in its three-dimensional form in presence of a wet or humidity environment. Additionally, great demands are made of the plastic films, particularly with respect to the tensile modulus thereof, since the formed articles have to exert sufficient tension during the time of its use.

    [0003] In the past, single-layer films, for example, consisting of a variety of thermoplastic materials have been employed for applications in wet or humidity environment, which, however, have the disadvantage that despite a high tensile modulus prior to the start of the use this tensile modulus falls off greatly during the period of its use, so that frequently the desired success of the use is not obtained as planned and a reworking of the three-dimensionally formed article becomes necessary. Such a reworking is very costly.

    [0004] In order to avoid this disadvantage, a demand has therefore existed for plastic films for the production three-dimensionally shaped products, with which the distinct drop in the tensile modulus during the period of the use in wet environment can be diminished.

    SUMMARY OF THE INVENTION



    [0005] The object that underlay the present invention accordingly consisted in providing suitable plastic films for the production of three-dimensionally shaped products, with which the distinct drop in the tensile modulus during the period of the its use can be diminished.

    [0006] Surprisingly, it has been found that a multi-layer, preferably three-layer, plastic film containing a core layer comprising a polycarbonate or copolycarbonate and/or a polyester or copolyester between two layers comprising a thermoplastic polyurethane and/or a polyester or copolyester with special properties eliminates the disadvantages listed above.

    DETAILED DESCRIPTION OF THE INVENTION



    [0007] The subject-matter of the present invention is therefore a dental device comprising a multi-layer plastic film, characterised in that
    • it has a core layer A containing at least one polycarbonate or copolycarbonate and/or a polyester or copolyester having a glass transition temperature Tg from 80 °C to 200°C, preferably from 80 °C to 170 °C, more preferably from 80°C to 150 °C
    • and this core layer is located between two outer layers B containing at least one thermoplastic polyurethane and/or polyester or copolyester exhibiting a hardness from 45 Shore D to 85 Shore D,
    wherein glass transition temperature Tg is determined by means of differential scanning calorimetry (DSC) according to standard DIN EN 61006 at a heating- rate of 20 K/min with definition of Tg as the midpoint temperature (tangent method); and
    wherein Shore hardness is determined in accordance with DIN EN ISO 868.

    [0008] Preferably according to the present invention the core layer A comprises at least one polyester or copolyester, wherein the inherent viscosity of the polyester or copolyester amounts to 0.50 dL/g to 1.20 dL/g and the polyester or copolyester exhibits a glass transition temperature Tg from 80 °C to 150 °C,
    wherein inherent viscosity is determined in 60/40 (wt/wt) phenol/ tetrachloroethane at a concentration of 0.5 g/100 ml at 25°C.

    [0009] Preferably according to the present invention the two outer layers B comprise at least one thermoplastic polyurethane exhibiting a hardness from 45 Shore D to 85 Shore D.

    [0010] In a preferred embodiment of the present invention the multi-layer plastic film
    • has a core layer A containing at least one polyester or copolyester having an inherent viscosity from 0.50 dL/g to 1.20 dL/g and a glass transition temperature Tg from 80°C to 150 °C
    • and this core layer A is located between two outer layers B containing at least one thermoplastic polyurethane exhibiting a hardness from 45 Shore D to 85 Shore D.


    [0011] Suitable and preferred polyester or copolyester for the core layer A are poly- or copolycondensates of terephthalic acid or naphthalene dicarboxylic acid, such as, for example and preferably, poly- or copolyethylene terephthalate (PET or CoPET), glycol-modified PET (PETG) or poly- or copolybutylene terephthalate (PBT or CoPBT), poly- or copolyethylene naphthalate (PEN or CoPEN).

    [0012] Suitable and preferred polycarbonates or copolycarbonates for the core layer A are in particular polycarbonates or copolycarbonates with average molecular weights Mw of from 500 to 100,000, preferably from 10,000 to 80,000, particularly preferably from 15,000 to 40,000.

    [0013] Additionally, blends containing at least one such polycarbonate or copolycarbonate are suitable and preferred for the core layer A. Blends of the abovementioned polycarbonates or copolycarbonates with at least one poly- or copolycondensate of terephthalic acid, in particular at least one such poly- or copolycondensate of terephthalic acid with average molecular weights Mw of from 10,000 to 200,000, preferably from 26,000 to 120,000, are furthermore also suitable and preferred. In particularly preferred embodiments of the invention, the blend is a blend of polycarbonate or copolycarbonate with poly- or copolybutylene terephthalate. Such a blend of polycarbonate or copolycarbonate with poly- or copolybutylene terephthalate can preferably be one with 1 to 90 wt.% of polycarbonate or copolycarbonate and 99 to 10 wt.% of poly- or copolybutylene terephthalate, preferably with 1 to 90 wt.% of polycarbonate and 99 to 10 wt.% of polybutylene terephthalate, the contents adding up to 100 wt.%. Such a blend of polycarbonate or copolycarbonate with poly- or copolybutylene terephthalate can particularly preferably be one with 20 to 85 wt.% of polycarbonate or copolycarbonate and 80 to 15 wt.% of poly- or copolybutylene terephthalate, preferably with 20 to 85 wt.% of polycarbonate and 80 to 15 wt.% of polybutylene terephthalate, the contents adding up to 100 wt.%. Such a blend of polycarbonate or copolycarbonate with poly- or copolybutylene terephthalate can very particularly preferably be one with 35 to 80 wt.% of polycarbonate or copolycarbonate and 65 to 20 wt.% of poly- or copolybutylene terephthalate, preferably with 35 to 80 wt.% of polycarbonate and 65 to 20 wt.% of polybutylene terephthalate, the contents adding up to 100 wt.%.

    [0014] In preferred embodiments, particularly suitable polycarbonates or copolycarbonates are aromatic polycarbonates or copolycarbonates.

    [0015] The polycarbonates or copolycarbonates can be linear or branched in a known manner.

    [0016] The preparation of these polycarbonates can be carried out in a known manner from diphenols, carbonic acid derivatives, optionally chain terminators and optionally branching agents. Details of the preparation of polycarbonates have been laid down in many patent specifications for about 40 years. Reference may be made here by way of example merely to Schnell, "Chemistry and Physics of Polycarbonates", Polymer Reviews, volume 9, Interscience Publishers, New York, London, Sydney 1964, to D. Freitag, U. Grigo, P. R. Müller, H. Nouvertne', BAYER AG, "Polycarbonates" in Encyclopedia of Polymer Science and Engineering, volume 11, second edition, 1988, pages 648-718 and finally to Dres. U. Grigo, K. Kirchner and P. R. Müller "Polycarbonate" in Becker/Braun, Kunststoff-Handbuch, volume 3/1, Polycarbonate, Polyacetale, Polyester, Celluloseester, Carl Hanser Verlag Munich, Vienna 1992, pages 117-299.

    [0017] Suitable diphenols can be, for example, dihydroxyaryl compounds of the general formula (III)

            HO-Z-OH     (III)

    wherein Z is an aromatic radical having 6 to 34 C atoms, which can contain one or more optionally substituted aromatic nuclei and aliphatic or cycloaliphatic radicals or alkylaryls or hetero atoms as bridge members.

    [0018] Particularly preferred dihydroxyaryl compounds are resorcinol, 4,4'-dihydroxydiphenyl, bis-(4-hydroxyphenyl)-diphenyl-methane, 1,1-bis-(4-hydroxyphenyl)-1-phenyl-ethane, bis-(4-hydroxyphenyl)-1-(1-naphthyl)-ethane, bis-(4-hydroxyphenyl)-1-(2-naphthyl)-ethane, 2,2-bis-(4-hydroxyphenyl)-propane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)-propane, 1,1-bis-(4-hydroxyphenyl)-cyclohexane, 1,1-bis-(3,5-dimethyl-4-hydroxyphenyl)-cyclohexane, 1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethyl-cyclohexane, 1,1'-bis-(4-hydroxyphenyl)-3-diisopropyl-benzene and 1,1'-bis-(4-hydroxyphenyl)-4-diisopropyl-benzene.

    [0019] Very particularly preferred dihydroxyaryl compounds are 4,4'-dihydroxydiphenyl, 2,2-bis-(4-hydroxyphenyl)-propane and bis-(4-hydroxyphenyl)-3,3,5 -trimethyl-cyclohexane.

    [0020] A very particularly preferred copolycarbonate can be prepared using 1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethyl-cyclohexane and 2,2-bis-(4-hydroxyphenyl)-propane.

    [0021] Suitable carbonic acid derivatives can be, for example, phosgene or diaryl carbonates of the general formula (IV)

    wherein

    [0022] R, R' and R" independently of each another are identical or different and represent hydrogen, linear or branched C1-C34-alkyl, C7-C34-alkylaryl or C6-C34-aryl, and R can furthermore also denote -COO- R'", wherein R'" represents hydrogen, linear or branched C1-C34- alkyl, C7-C34-alkylaryl or C6-C34-aryl.

    [0023] Particularly preferred diaryl compounds are diphenyl carbonate, 4-tert-butylphenyl phenyl carbonate, di-(4-tert-butylphenyl) carbonate, biphenyl-4-yl phenyl carbonate, di-(biphenyl-4-yl) carbonate, 4-(1-methyl-1-phenylethyl)- phenyl phenyl carbonate, di-[4-(1-methyl-1-phenylethyl)-phenyl] carbonate and di-(methyl salicylate) carbonate.

    [0024] Diphenyl carbonate is very particularly preferred.

    [0025] Either one diaryl carbonate or different diaryl carbonates can be used

    [0026] One or more monohydroxyaryl compound(s) which has/have not been used for the preparation of the diaryl carbonate(s) used can additionally be employed, for example, as chain terminators to control or vary the end groups. These can be those of the general formula (V)

    wherein

    RA represents linear or branched C1-C34-alkyl, C7-C34-alkylaryl, C6-C34-aryl or -COO-RD, wherein RD represents hydrogen, linear or branched C1-C34-alkyl, C7-C34-alkylaryl or C6-C34-aryl, and

    RB, RC independently of each other are identical or different and represent hydrogen, linear or branched C1-C34-alkyl, C7-C34-alkylaryl or C6-C34-aryl.

    4-tert-Butylphenol, 4-iso-octylphenol and 3-pentadecylphenol are preferred.



    [0027] Suitable branching agents can be compounds with three and more functional groups, preferably those with three or more hydroxyl groups.

    [0028] Preferred branching agents are 3,3-bis-(3-methyl-4-hydroxyphenyl)-2-oxo-2,3-dihydroindole and 1,1,1-tris-(4-hydroxyphenyl)-ethane.

    [0029] For the core layer A poly- or copolyalkylene terephthalates or poly- or copolyalkylene naphthalates are suitable in preferred embodiments of the invention as poly- or copolycondensates of terephthalic acid or naphthalene dicarboxylic acid. Suitable poly- or copolyalkylene terephthalates or poly- or copolyalkylene naphthalates are for example reaction products of aromatic dicarboxylic acids or reactive derivatives thereof (for example dimethyl esters or anhydrides) and aliphatic, cycloaliphatic or araliphatic diols and mixtures of these reaction products.

    [0030] As used herein, the term "terephthalic acid" is intended to include terephthalic acid itself and residues thereof as well as any derivative of terephthalic acid, including its associated acid halides, esters, half-esters, salts, half-salts, anhydrides, mixed anhydrides, or mixtures thereof or residues thereof useful in a reaction process with a diol to make polyester. In one embodiment, the esters are chosen from at least one of the following: methyl, ethyl, propyl, isopropyl, and phenyl esters. In one embodiment, terephthalic acid may be used as the starting material. In another embodiment, dimethyl terephthalate may be used as the starting material. In another embodiment, mixtures of terephthalic acid and dimethyl terephthalate may be used as the starting material and/or as an intermediate material.

    [0031] As used herein, the term "naphthalene dicarboxylic acid" is intended to include naphthalene dicarboxylic acid itself and residues thereof as well as any derivative of naphthalene dicarboxylic acid, including its associated acid halides, esters, half-esters, salts, half-salts, anhydrides, mixed anhydrides, or mixtures thereof or residues thereof useful in a reaction process with a diol to make polyester. In one embodiment, the esters are chosen from at least one of the following: methyl, ethyl, propyl, isopropyl, and phenyl esters. In one embodiment, naphthalene dicarboxylic acid may be used as the starting material. In another embodiment, the dimethylester of naphthalene dicarboxylic acid may be used as the starting material. In another embodiment, mixtures of terephthalic acid and the dimethylester of naphthalene dicarboxylic acid may be used as the starting material and/or as an intermediate material.

    [0032] In addition to terephthalic acid or naphthalene dicarboxylic acid, the dicarboxylic acid component of the poly- or copolyester useful in the invention can optionally comprises up to 30 mole %, preferably up to 20 mole %, more preferably up to 10 mole %, most preferably up to 5 mole % of one or more modifying aromatic dicarboxylic acids. In one preferred embodiment the dicarboxylic acid component of the poly- or copolyester useful in the invention comprise up to 1 mole % of one or more modifying aromatic dicarboxylic acids. Yet in another preferred embodiment the dicarboxylic acid component of the poly- or copolyester useful in the invention comprises 0 mole % modifying aromatic dicarboxylic acids. Thus, if present, it is contemplated that the amount of one or more modifying aromatic dicarboxylic acids can range from any of these preceding endpoint values including, for example, from 0.01 to 30 mole %, preferably from 0.01 to 20 mole %, more preferably from 0.01 to 10 mole %, most preferably from 0.01 to 5 mole % and in a preferred embodiment from 0.01 to 1 mole. In one embodiment, modifying aromatic dicarboxylic acids that may be used in the present invention include but are not limited to those having up to 20 carbon atoms, preferably having 8 to 14 carbon atoms, and which can be linear, para-oriented, or symmetrical. Examples of modifying aromatic dicarboxylic acids which may be used in this invention include, but are not limited to, phthalic acid, isophthalic acid, 4,4'-biphenyldicarboxylic acid, 1,4-, 1,5-, 2,6-, 2,7-naphthalenedicarboxylic acid (in case of poly- or copolyalkylene terephthalates), terephthalic acid (in case of poly- or copolyalkylene naphthalates) and trans-4,4'-stilbenedicarboxylic acid, and esters thereof.

    [0033] The carboxylic acid component of the copolyesters useful in the invention can optionally be further modified with up to 10 mole %, such as up to 5 mole % or preferably up to 1 mole % of one or more aliphatic dicarboxylic acids containing 2 to 16 carbon atoms, such as, for example, malonic, succinic, glutaric, adipic, pimelic, suberic, azelaic, sebacic, cyclohexane diacetic and dodecanedioic dicarboxylic acids. Yet another embodiment contains 0 mole % modifying aliphatic dicarboxylic acids. Thus, if present, it is contemplated that the amount of one or more modifying aliphatic dicarboxylic acids can range from any of these preceding endpoint values including, for example, from 0.01 to 10 mole % and preferably from 0.1 to 10 mole %.

    [0034] Preferred poly- or copolyalkylene terephthalates or poly- or copolyalkylene naphthalates contain at least 70 mole %, preferably at least 80 mole % ethylene glycol, butanediol-1,4, 2,2,4,4-tetramethyl-1,3-cyclobutanediol and/or 1,4-cyclohexanedimethanol residues, relative to the diol component.

    [0035] The preferred poly- or copolyalkylene terephthalates or poly- or copolyalkylene naphthalates can contain in addition to ethylene glycol, butanediol-1,4, 2,2,4,4-tetramethyl-1,3-cyclobutanediol and/or 1,4-cyclohexanedimethanol residues up to 30 mole %, preferably up to 20 mole % of other aliphatic diols having 3 to 12 C atoms or cycloaliphatic diols having 6 to 21 C atoms, for example radicals of propanediol-1,3,2-ethylpropanediol-1,3, neopentyl glycol, pentanediol-1,5, hexanediol-1,6, cyclohexane dimethanol-1,4, 3-methylpentanediol-2,4, 2-methylpentanediol-2,4, 2,2,4-trimethylpentanediol-1,3 and 2-ethylhexanediol-1,6,2,2-diethylpropanediol-1,3,hexanediol-2,5, 1,4-di-([beta] -hydroxyethoxy)-benzene, 2,2-bis-(4-hydroxycyclohexyl)propane, 2,4-dihydroxy-1,1,3,3-tetramethylcyclobutane, 2,2-bis-(3-[beta]-hydroxyethoxyphenyl)propane and 2,2-bis-(4-hydroxypropoxyphenyl)propane (cf. DE-OS 24 07 674, 24 07 776, 27 15 932).

    [0036] The poly- or copolyesters of the invention can comprise from 0 to 10 mole %, for example, from 0.01 to 5 mole % based on the total mole percentages of either the diol or diacid residues, respectively, of one or more residues of a branching monomer, also referred to herein as a branching agent, having 3 or more carboxyl substituents, hydroxyl substituents, or a combination thereof. In certain embodiments, the branching monomer or agent may be added prior to and/or during and/or after the polymerization of the poly- or copolyester. The poly- or copolyester(s) useful in the invention can thus be linear or branched. In preferred embodiments the poly- or copolyester(s) useful in the invention are linear and thus do not contain such branching agent.

    [0037] Examples of branching monomers, if present, include, but are not limited to, multifunctional acids or multifunctional alcohols such as trimellitic acid, trimellitic anhydride, pyromellitic dianhydride, trimethylolpropane, glycerol, pentaerythritol, citric acid, tartaric acid, 3-hydroxyglutaric acid and the like. In one embodiment, the branching monomer residues can comprise 0.1 to 0.7 mole percent of one or more residues chosen from at least one of the following: trimellitic anhydride, pyromellitic dianhydride, glycerol, sorbitol, 1,2,6-hexanetriol, pentaerythritol, trimethylolethane, and/or trimesic acid. The branching monomer may be added to the copolyester reaction mixture or blended with the copolyester in the form of a concentrate as described, for example, in U.S. Patent Nos. 5,654,347 and 5,696,176.

    [0038] Preferred poly- or copolyalkylene terephthalates or poly- or copolyalkylene naphthalates contain at least 70 mole %, preferably 80 mole % terephthalic acid or naphthalene dicarboxylic acid residues, relative to the dicarboxylic acid component, and at least 70 mole %, preferably at least 80 mole % ethylene glycol, butanediol-1,4, 2,2,4,4-tetramethyl-1,3-cyclobutanediol and/or 1,4-cyclohexanedimethanol residues, relative to the diol component.

    [0039] In one particularly preferred embodiment the core layer A comprises at least one copolyester produced solely from terephthalic acid and reactive derivatives thereof (for example dialkyl esters thereof) and ethylene glycol and/or butanediol-1,4.

    [0040] In another particularly preferred embodiment the core layer A comprises at least one blend of polycarbonate or copolycarbonate with poly- or copolybutylene terephthalate with 1 to 90 wt.% of polycarbonate or copolycarbonate and 99 to 10 wt.% of poly- or copolybutylene terephthalate, preferably with 35 to 80 wt.% of polycarbonate and 65 to 20 wt.% of polybutylene terephthalate, the contents adding up to 100 wt.%.

    [0041] In another particularly preferred embodiment of the present invention the core layer A comprises at least one copolyester that exhibits residues from
    1. (a) a dicarboxylic acid component comprising
      1. i) 70 mole % to 100 mole % terephthalic acid residues,
      2. ii) 0 mole % to 30 mole % aromatic dicarboxylic acid residues with up to 20 carbon atoms, and
      3. iii) 0 mole % to 10 mole % aliphatic dicarboxylic acid residues with up to 16 carbon atoms, and
    2. (b) a diol component comprising
      1. i) 5 mole % to 50 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues, and
      2. ii) 50 mole % to 95 mole % 1,4-cyclohexanedimethanol residues,
    wherein the sum of the mole % of residues i) - iii) of the dicarboxylic acid component amounts to 100 mole % and the sum of the mole % of residues i) and ii) of the diol component amounts to 100 mole %.

    [0042] The two outer layers B preferably comprise at least one thermoplastic polyurethane exhibiting a hardness from 45 Shore D to 85 Shore D.

    [0043] Particularly preferably such at least one thermoplastic polyurethane is obtainable from
    1. a) one or more linear polyether diols with mean molecular weights from 500 g/mol to 10,000 g/mol, preferably 500 g/mol to 6000 g/mol, and, on average, in each instance at least 1.8 and at most 3.0, preferably 1.8 to 2.2, Tserevitinov-active hydrogen atoms
    2. b) one or more organic diisocyanates,
    3. c) one or more diol chain-extenders with molecular weights from 60 g/mol to 500 g/mol and with, on average, 1.8 to 3.0 Tserevitinov-active hydrogen atoms
      in the presence of
    4. d) optionally, one or more catalysts
      with addition of
    5. e) optionally, auxiliary substances and additives,
    wherein the molar ratio of the NCO groups in b) to the groups in a) and c) that are reactive towards isocyanate amounts to 0.85:1 to 1.2:1, preferably 0.9:1 to 1.1:1.

    [0044] In a particularly preferred embodiment of the present application the multi-layer plastic film is characterised in that
    • it has a core layer A containing at least one copolyester that exhibits residues from
      1. (a) a dicarboxylic acid component comprising
        1. i) 70 mole % to 100 mole % terephthalic acid residues,
        2. ii) 0 mole % to 30 mole % aromatic dicarboxylic acid residues with up to 20 carbon atoms, and
        3. iii) 0 mole % to 10 mole % aliphatic dicarboxylic acid residues with up to 16 carbon atoms, and
      2. (b) a diol component comprising
        1. i) 5 mole % to 50 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues, and
        2. ii) 50 mole % to 95 mole % 1,4-cyclohexanedimethanol residues,
        wherein the sum of the mole % of residues i) - iii) of the dicarboxylic acid component amounts to 100 mole % and the sum of the mole % of residues and ii) of the diol component amounts to 100 mole %
        and wherein the inherent viscosity of the copolyester amounts to 0.50 dL/g to 1.20 dL/g and the copolyester exhibits a glass transition temperature Tg from 80 °C to 150 °C,
    • and this core layer is located between two outer layers B containing at least one thermoplastic polyurethane, the thermoplastic polyurethane exhibiting a hardness from 45 Shore D to 85 Shore D and being obtainable from
      1. a) one or more linear polyether diols with mean molecular weights from 500 g/mol to 10,000 g/mol, preferably 500 g/mol to 6000 g/mol, and, on average, in each instance at least 1.8 and at most 3.0, preferably 1.8 to 2.2, Tserevitinov-active hydrogen atoms
      2. b) one or more organic diisocyanates,
      3. c) one or more diol chain-extenders with molecular weights from 60 g/mol to 500 g/mol and with, on average, 1.8 to 3.0 Tserevitinov-active hydrogen atoms
        in the presence of
      4. d) optionally, one or more catalysts
        with addition of
      5. e) optionally, auxiliary substances and additives,
      wherein the molar ratio of the NCO groups in b) to the groups in a) and c) that are reactive towards isocyanate amounts to 0.85:1 to 1.2:1, preferably 0.9:1 to 1.1:1.


    [0045] The film according to the invention surprisingly exhibits a distinctly smaller drop in the tensile modulus under wet or humidity conditions. Moreover, the three-dimensional shaped articles made from such a film according to the invention are stable in its three-dimensional shape under such conditions.

    [0046] Thermoplastic polyurethanes (TPU) are mostly constructed from linear polyols (macrodiols) such as polyester diols, polyether diols or polycarbonate diols, organic diisocyanates and short-chain, mostly difunctional, alcohols (chain-extenders). They may be produced continuously or discontinuously. The most well-known production processes are the belt process (GB-A 1,057,018) and the extruder process (DE-A 1 964 834).

    [0047] The thermoplastic polyurethanes preferably employed in accordance with the invention are reaction products formed from the aforementioned
    1. a) polyether diols
    2. b) organic diisocyanates
    3. c) chain-extenders.


    [0048] By way of diisocyanates b), use may be made of aromatic, aliphatic, araliphatic, heterocyclic and cycloaliphatic diisocyanates or mixtures of these diisocyanates (cf. HOUBEN-WEYL "Methoden der organischen Chemie", Volume E20 "Makromolekulare Stoffe", Georg Thieme Verlag, Stuttgart, New York 1987, pp 1587-1593 or "Justus Liebigs Annalen der Chemie", 562, pages 75 to 136).

    [0049] In detail, let the following be mentioned in exemplary manner: aliphatic diisocyanates, such as hexamethylene diisocyanate, cycloaliphatic diisocyanates, such as isophorone diisocyanate, 1,4-cyclohexane diisocyanate, 1-methyl-2,4-cyclohexane diisocyanate and 1-methyl-2,6-cyclohexane diisocyanate and also the corresponding isomer mixtures, 4,4'-dicyclohexylmethane diisocyanate, 2,4'-dicyclohexylmethane diisocyanate and 2,2'-dicyclohexylmethane diisocyanate and also the corresponding isomer mixtures, aromatic diisocyanates, such as 2,4-toluylene diisocyanate, mixtures consisting of 2,4-toluylene diisocyanate and 2,6-toluylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane - diisocyanate and 2,2'-diphenylmethane diisocyanate, mixtures consisting of 2,4'-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate, urethane-modified liquid 4,4'-diphenylmethane diisocyanates and 2,4'-diphenylmethane - diisocyanates, 4,4'-diisocyanatodiphenylethane-(1,2) and 1,5-naphthylene diisocyanate. Use is preferentially made of 1,6-hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, diphenylmethane-diisocyanate isomer mixtures with a content of 4,4'-diphenylmethane diisocyanate of more than 96 wt.% and, in particular, 4,4'-diphenylmethane diisocyanate and 1,5-naphthylene diisocyanate. The stated diisocyanates may find application individually or in the form of mixtures with one another. They may also be used together with up to 15 wt.% (calculated with respect to the total quantity of diisocyanate) of a polyisocyanate, for example triphenylmethane-4,4',4"-triisocyanate or polyphenyl-polymethylene polyisocyanates.

    [0050] In the case of the organic diisocyanate(s) b) it is preferably a question of one or more isocyanate(s) selected from the group containing 4,4'-diphenylmethane diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate and 1,6-hexamethylene diisocyanate.
    Tserevitinov-active polyether diols a) are those with, on average, at least 1.8 to at most 3.0, preferably 1.8 to 2.2, Tserevitinov-active hydrogen atoms.

    [0051] Designated as Tserevitinov-active hydrogen atoms are all hydrogen atoms bonded to N, O or S that yield methane by conversion with methylmagnesium halide in accordance with a process discovered by Tserevitinov. The determination takes place after the Tserevitinov reaction, whereby methylmagnesium iodide is converted with the compound to be investigated and reacts with acid hydrogen to form a magnesium salt and the corresponding hydrocarbon. The methane arising is determined by gas-volumetric analysis.

    [0052] Suitable such polyether diols can be produced by one or more alkylene oxides with 2 to 4 carbon atoms in the alkylene residue being converted with a starter molecule that contains two active hydrogen atoms in bonded form. By way of alkylene oxides, let the following be mentioned, for example: ethylene oxide, 1,2-propylene oxide, epichlorohydrin, 1,2-butylene oxide and 2,3-butylene oxide. The alkylene oxides may be used individually, alternately in succession or as mixtures. By way of starter molecules there enter into consideration, for example: water, amino alcohols, such as N-alkyldiethanolamines, for example N-methyldiethanolamine, and diols such as ethylene glycol, 1,3-propylene glycol, 1,4-butanediol and 1,6-hexanediol. Optionally, mixtures of starter molecules may also be employed. Suitable polyether diols are furthermore the hydroxyl-group-containing polymerisation products of tetrahydrofuran and/or of 1,3-propylene glycol. Trifunctional polyethers in proportions from 0 wt.% to 30 wt.%, relative to the bifunctional polyethers, may also be employed, but at most in such quantity that a product arises that is still thermoplastically workable.

    [0053] The polyether diols preferentially possess number-average molecular weights Mn from 500 g/mol to 8000 g/mol, particularly preferably 500 g/mol to 6000 g/mol. They may find application both individually and in the form of mixtures with one another.

    [0054] The number-average molecular weights Mn can be determined with endgroup determination, such as determination of hydroxyl numbers according to ASTM D 4274.

    [0055] Tserevitinov-active chain-extenders c) are so-called chain-extension agents and possess, on average, 1.8 to 3.0 Tserevitinov-active hydrogen atoms and have a number-average molecular weight from 60 g/mol to 500 g/mol. Such agents are understood to be - besides compounds exhibiting amino groups, thiol groups or carboxyl groups - those with two to three, preferably two, hydroxyl groups. Hydroxyl compounds with two to three, preferably two, hydroxyl groups are particularly preferred as chain-extenders.

    [0056] Employed by way of chain-extension agents are, for example and preferably, diols or diamines with a molecular weight from 60 g/mol to 500 g/mol, preferentially aliphatic diols with 2 to 14 carbon atoms, such as, for example, ethanediol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol and dipropylene glycol. Also suitable, however, are diesters of terephthalic acid with glycols with 2 to 4 carbon atoms, for example terephthalic acid-bis-ethylene glycol or terephthalic acid-bis-1,4-butanediol, hydroxyalkylene ethers of hydroquinone, for example 1,4-di(β-hydroxyethyl)hydroquinone, ethoxylated bisphenols, for example 1,4-di(β-hydroxyethyl)bisphenol A, (cyclo)aliphatic diamines, such as isophoronediamine, ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, N-methylpropylene-1,3-diamine,, N,N'-dimethylethylenediamine, and aromatic diamines, such as 2,4-toluylenediamine, 2,6-toluylenediamine, 3,5-diethyl-2,4-toluylenediamine or 3,5-diethyl-2,6-toluylenediamine or primary mono-, di-, tri- or tetraalkyl-substituted 4,4'-diaminodiphenylmethanes. Particularly preferably, use is made of 1,2-ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,4-di(β-hydroxyethyl)hydroquinone or 1,4-di(β-hydroxyethyl)bisphenol A by way of chain-extenders. Mixtures of the aforementioned chain-extenders may also be employed. In addition, relatively small quantities of triols may also be added.

    [0057] The number-average molecular weights Mn can be determined with endgroup determination, such as determination of hydroxyl numbers according to ASTM D 4274.

    [0058] In the case of the diol chain-extender(s) c) it is preferably a question of one or more selected from the group containing 1,4-butanediol, 1,3-propanediol, 1,2-propanediol, 1,2-ethylene glycol, 1,6 hexanediol, 1,4-di(β-hydroxyethyl)hydroquinone and 1,4-di(β-hydroxyethyl)bisphenol A.

    [0059] Reactive groups towards isocyanate in a) and c) are in particular Tserevitinov-active hydrogen atoms containing groups.

    [0060] The relative quantities of compounds a) and c) are preferably so chosen that the ratio of the sum of the isocyanate groups in b) to the sum of the Tserevitinov-active hydrogen atoms in a) and c) amounts to 0.85:1 to 1.2:1, particularly preferably 0.9:1 to 1.1:1.

    [0061] The thermoplastic polyurethanes employed in accordance with the invention may optionally contain catalysts d). Suitable catalysts are the tertiary amines that are known and conventional in accordance with the state of the art, such as, for example, triethylamine, dimethylcyclohexylamine, N-methylmorpholine, N,N'-dimethylpiperazine, 2-(dimethylaminoethoxy)ethanol, diazabicyclo[2,2,2]octane and similar and also, in particular, organic metallic compounds such as titanic acid esters, iron compounds or tin compounds, such as tin diacetate, tin dioctoate, tin dilaurate, or the dialkyltin salts of aliphatic carboxylic acids, such as dibutyltin diacetate or dibutyltin dilaurate or similar. Preferred catalysts are organic metallic compounds, in particular titanic acid esters, iron compounds and tin compounds. The total quantity of catalysts in the thermoplastic polyurethanes amounts, as a rule, to about 0 wt.% to 5 wt.%, preferably 0 wt.% to 2 wt.%, relative to the total weight of the TPU.

    [0062] The thermoplastic polyurethanes (TPU) employed in accordance with the invention may optionally contain, by way of auxiliary substances and additives e), 0 wt.% up to at most 20 wt.%, preferably 0 wt.% to 10 wt.%, relative to the total weight of the TPU, of the conventional auxiliary substances and additives. Typical auxiliary substances and additives are pigments, dyestuffs, flame retardants, stabilisers against the influences of ageing and weathering, plasticisers, slip additives, mould-release agents, chain terminators, substances acting fungistatically and bacteriostatically and also fillers and mixtures thereof.

    [0063] By way of such additives, inter alia compounds that are monofunctional in relation to isocyanates may preferably be employed in proportions up to 2 wt.%, relative to the total weight of the thermoplastic polyurethane, as so-called chain terminators or mould-release aids. Suitable are, for example, monoamines such as butylamine and dibutylamine, octylamine, stearylamine, N-methylstearylamine, pyrrolidine, piperidine or cyclohexylamine, monoalcohols such as butanol, 2-ethylhexanol, octanol, dodecanol, stearyl alcohol, the various amyl alcohols, cyclohexanol and ethylene glycol monomethyl ether.

    [0064] Examples of further additives are slip additives, such as fatty-acid esters, the metallic soaps thereof, fatty-acid amides, fatty-acid ester amides and silicone compounds, anti-blocking agents, inhibitors, stabilisers against hydrolysis, light, heat and discoloration, flame retardants, dyestuffs, pigments, inorganic and/or organic fillers, for example polycarbonates, and also plasticisers and reinforcing agents. Reinforcing agents are, in particular, fibrous reinforcing substances such as, for example, inorganic fibres, which are produced in accordance with the state of the art and which may also have been subjected to a sizing material. Further particulars concerning the stated auxiliary substances and additives can be gathered from the specialist literature, for example from the monograph by J.H. Saunders and K.C. Frisch entitled "High Polymers", Volume XVI, Polyurethanes: Chemistry and Technology, Parts 1 and 2, Interscience Publishers 1962 and 1964, from the Taschenbuch der Kunststoff-Additive by R.Gächter u. H.Müller (Hanser Verlag Munich 1990) or from DE-A 29 01 774.

    [0065] The thermoplastic polyurethanes employed in accordance with the invention preferably exhibit a hardness from 50 Shore D to 80 Shore D. The Shore hardness is determined in accordance with DIN EN ISO 868.

    [0066] The thermoplastic polyurethanes employed in accordance with the invention can be produced continuously in the so-called extruder process, for example in a multiple-shaft extruder, or in the so-called belt process. The metering of the TPU components a), b) and c) can be undertaken simultaneously, i.e. in the one-shot process, or in succession, i.e. by means of a prepolymer process. The prepolymer process is particularly preferred. In this connection the prepolymer may be produced both by charging in batches and continuously in a part of the extruder or in a separate upstream prepolymer unit, for example in a static-mixer reactor, for example a Sulzer mixer.

    [0067] The preferred polyester or copolyester, in particular copolyester employed in accordance with the invention preferably exhibits a glass transition temperature Tg from 85 °C to 130 °C, particularly preferably from 90 °C to 120 °C.

    [0068] The polyester or copolyester, in particular copolyester employed in accordance with the invention preferably exhibits an inherent viscosity from 0.50 dL/g to 0.80 dL/g.

    [0069] Preferred copolyesters used in the present invention typically can be prepared by the reaction of terephthalic acid and optionally one or more additional difunctional carboxylic acids and/or multifunctional carboxylic acids - hereinafter referred to as dicarboxylic acid component - with at least the two difunctional hydroxyl compounds 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 1,4-cyclohexanedimethanol and optionally additional difunctional hydroxyl compounds and/or multifunctional hydroxyl compounds - hereinafter referred to as diol component. Typically the dicarboxylic acid component can be one or more dicarboxylic acid(s) and the diol compound can be two or more dihydric alcohols/glycols. The dicarboxylic acids and alcohols/glycols preferably react in substantially equal proportions and are incorporated into the copolyester polymer as their corresponding residues. The copolyesters used according to the present invention, therefore, can contain substantially equal molar proportions of acid residues and diol residues.

    [0070] The term "residue", as used herein, means any organic structure incorporated into a polymer through a polycondensation and/or an esterification reaction from the corresponding monomer.

    [0071] The dicarboxylic acid residues may be derived from a dicarboxylic acid monomer or its associated acid halides, esters, salts, anhydrides, or mixtures thereof. As used herein, therefore, the term "dicarboxylic acid" is intended to include dicarboxylic acids and any derivative of a dicarboxylic acid, including its associated acid halides, esters, half-esters, salts, half-salts, anhydrides, mixed anhydrides, or mixtures thereof, useful in a reaction process with a diol to make (co)polyester.

    [0072] The dicarboxylic acid component in the particularly preferred embodiment comprises 70 to 100 mole % of terephthalic acid residues, preferably 80 to 100 mole % of terephthalic acid residues, more preferably 90 to 100 mole % of terephthalic acid residues, most preferably 95 to 100 mole % of terephthalic acid residues. In a particularly preferred embodiment the dicarboxylic acid component comprises 98 to 100 mole % of terephthalic acid residues. In another particularly preferred embodiment the dicarboxylic acid component comprises 100 mole % of terephthalic acid residues.

    [0073] The total mole % of the dicarboxylic acid component is 100 mole %.

    [0074] Esters and/or salts of the modifying dicarboxylic acids may be used instead of the dicarboxylic acids. Suitable examples of dicarboxylic acid esters include, but are not limited to, the dimethyl, diethyl, dipropyl, diisopropyl, dibutyl, and diphenyl esters. In one embodiment, the esters are chosen from at least one of the following: methyl, ethyl, propyl, isopropyl, and phenyl esters.

    [0075] The ratio of 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues and 1,4-cyclohexanedimethanol residues from the diol component of the copolyester preferably amounts to 10 mole % to 35 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues to 65 mole % to 90 mole % 1,4-cyclohexanedimethanol residues, particularly preferably 15 mole % to 35 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues to 65 mole % to 85 mole % 1,4-cyclohexanedimethanol residues, quite particularly preferably 15 mole % to 30 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues to 70 mole % to 85 mole % 1,4-cyclohexanedimethanol residues, whereby the sum of the mole % of these two components of the diol component amounts to 100 mole %.

    [0076] The diol component of the copolyester(s) in the particularly preferred embodiment can contain 25 mole % or less of one or more modifying diols which are not 2,2,4,4-tetramethyl-1,3-cyclobutanediol or 1,4-cyclohexanedimethanol. In one embodiment, the copolyesters useful in the invention may contain 15 mole % or less of one or more modifying diols. In another embodiment, the copolyesters useful in the invention can contain 10 mole % or less of one or more modifying diols. In another embodiment, the copolyesters useful in the invention can contain 5 mole % or less of one or more modifying diols. In another embodiment, the copolyesters useful in the invention can contain 3 mole % or less of one or more modifying diols. In another embodiment, the copolyesters useful in the invention can contain 0 mole % modifying diols. Certain embodiments can also contain 0.01 or more mole %, such as 0.1 or more mole %, 1 or more mole %, 5 or more mole %, or 10 or more mole % of one or more modifying diols. Thus, if present, it is contemplated that the amount of one or more modifying diols can range from any of these preceding endpoint values including, for example, from 0.01 to 15 mole % and preferably from 0.1 to 10 mole %.

    [0077] Modifying diols useful in the copolyester(s) useful in the invention refer to diols other than 2,2,4,4,-tetramethyl-1,3-cyclobutanediol and 1,4-cyclohexanedimethanol and may contain 2 to 16 carbon atoms. Examples of suitable modifying diols include, but are not limited to, ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, p-xylene glycol or mixtures thereof. Preferred modifying diols, if present, are ethylene glycol, 1,3-propanediol and/or 1,4-butanediol.

    [0078] Each of the diols 2,2,4,4-tetramethyl-1,3-cyclobutanediol or1,4-cyclohexanedimethanol may be cis, trans, or a mixture thereof.

    [0079] For the desired copolyester, the molar ratio of cis/trans 2,2,4,4-tetramethyl-1,3-cyclobutanediol can vary from the pure form of each or mixtures thereof. In certain embodiments, the molar percentages for cis and/or trans 2,2,4,4-tetramethyl-1,3-cyclobutanediol are greater than 50 mole % cis and less than 50 mole % trans; or greater than 55 mole % cis and less than 45 mole % trans; or 30 to 70 mole % cis and 70 to 30 mole % trans; or 40 to 60 mole % cis and 60 to 40 mole % trans; wherein the total sum of the mole percentages for cis- and trans-2,2,4,4-tetramethyl-1,3-cyctobutanediol is equal to 100 mole %.

    [0080] For the desired copolyester, the molar ratio of 1,4-cyclohexanedimethanol can vary from the pure form of each or mixtures thereof. By using a mixture of cis and trans the molar ratio of cis/trans 1,4-cyclohexanedimethanol can vary within the range of 50/50 to 0/100, for example, between 40/60 to 20/80.

    [0081] The poly- or copolyester useful in the invention can be made by processes known from the literature such as, for example, by processes in homogenous solution, by transesterfication processes in the melt, and by two phase interfacial processes. Suitable methods include, but are not limited to, the steps of reacting one or more dicarboxylic acids with one or more diols at a temperature of 100°C to 315°C at a pressure of 0.13 mbar to 1011 mbar (0.1 to 760 mm Hg) for a time sufficient to form a polyester. See U.S. Patent No. 3,772,405 or Kunststoff-Handbuch, Vol. VIII, p. 695 ff, Karl-Hanser-Verlag, Munich 1973 for methods of producing (co)polyesters.

    [0082] Suitable polycarbonates or copolycarbonates useful in the invention are commercially available, for example under the trademark Makrolon® from Bayer MaterialScience AG. Suitable polyesters or copolyesters useful in the invention are also commercially available, for example under the trademark Skygreen from SK Chemical or Tritan™ from Eastman Chemical Company. Suitable thermoplastic polyurethanes useful in the invention are also commercially available, e.g. from Bayer MaterialScience AG.

    [0083] The plastic film according to the invention preferably exhibits a total thickness from 300 µm to 2000 µm, particularly preferably from 400 µm to 1500 µm, quite particularly preferably from 500 µm to 1200 µm.

    [0084] In the case of the plastic film according to the invention, in a preferred embodiment it is a question of a three-layer film consisting of the core layer A between the two outer layers B.

    [0085] This preferred embodiment of the plastic film according to the invention displays an excellent adhesion between the core layer A, particularly preferred the copolyester core layer A, and the outer layers B, particularly preferred the TPU outer layers B. Good adhesion between these layers is particularly advantageous and necessary, since a delamination of the plastic film during its use in a wet or humidity environment is undesirable. Moreover, after the production of three-dimensional shaped articles e.g. by means of thermoforming of the film according to the invention and trimming on the cut edges, the articles have to be ground. Also in the course of this grinding process a delamination of the individual layers is undesirable.

    [0086] The adhesive force between the core layer A and the outer layers B preferably amounts to more than 0.3 N/mm, preferably more than 0.5 N/mm. Adhesive force is determined in accordance with ASTM D 903 98.

    [0087] The core layer A of the plastic film according to the invention preferably exhibits a layer thickness from 250 µm to 1600 µm, particularly preferably from 350 µm to 1400 µm, quite particularly preferably from 400 µm to 1000 µm. The outer layers B of the plastic film according to the invention preferably exhibit in each instance a layer thickness from 25 µm to 500 µm, particularly preferably from 30 µm to 300 µm, quite particularly preferably from 50 µm to 200 µm.

    [0088] For some application e.g. for medical applications it is, inter alia, also desirable that the film for the production of the shaped articles is as inconspicuous as possible during the course of usage. Therefore it is furthermore advantageous if the plastic film is as transparent as possible. This requirement is likewise satisfied by the film according to the invention.

    [0089] The plastic film according to the invention preferably exhibits a transmission of visible light within the wavelength range from 380 nm to 780 nm of more than 70 %, particularly preferably of more than 80 %. The transmission is determined in accordance with ASTM D 1003 - for example, with an Ultra Scan XE produced by Hunter Associates Laboratory Inc.

    [0090] The plastic film according to the invention can be produced by means of co-extrusion or double lamination. Production by means of co-extrusion is preferred.

    [0091] The production of multi-layer plastic films by means of co-extrusion is known to a person skilled in the art. In this connection, for the respective plastic layers the respective plastics, for example and preferably in the form of granular materials, are fused in a compounding extruder and are extruded into a film via a nozzle.

    [0092] In the course of the double lamination, firstly two films are produced for the two outer layers B, preferentially by means of extrusion, and the core layer A is produced by running the melt in between these two plastic films.

    [0093] By reason of their outstanding properties - such as, for example, slight drop in the tensile modulus, stability in its three-dimensional shape and good transparency - the plastic films according to the invention are particularly well suited for the purpose of producing three-dimensionally shaped articles. For the purpose of producing such 3D-shaped articles, shaping into the appropriate shape is effected by means of thermoforming from the plastic films according to the invention, and the latter is subsequently cut and polished.

    [0094] Therefore, a further object of the present invention is a three-dimensionally shaped article obtained from the multi-layered film according to the present invention, in particular by means of thermoforming.

    [0095] The plastic films according to the invention are particularly well suited for the purpose of producing three-dimensionally shaped articles, in particular for use in medical applications, such as for orthopaedic devices, e.g. orthopaedic supports, dental devices, e.g. dental splints or retainers, or splints, e.g. for stabilizing sprained joints or fractures. Additionally the plastic films according to the invention are particularly well suited for the purpose of producing three-dimensionally shaped articles for non-medical applications, such as photovoltaic or (underfloor) heating applications. Moreover, the plastic films according to the invention could particularly be well suited for bullet-proof glass laminates.

    [0096] The following Examples serve for exemplary elucidation of the invention and are not to be interpreted as limitation.

    EXAMPLES


    Feed materials



    [0097] 

    ISOPLAST 2530: commercial aromatic transparent thermoplastic polyurethane for medical applications with a Shore hardness of 82 D according to DIN EN ISO 868 (Lubrizol Corp.)

    DESMOPAN DP 9365 D: commercial aromatic transparent thermoplastic polyether polyurethane with a Shore hardness of 65 D according to DIN EN ISO 868 (Bayer MaterialScience AG)

    Copolyester I: Copolycondensate of terephthalic acid consisting of 48.4 wt.% terephthalic acid, 11.9 wt.% (23 mole % relative to the diol component) 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 39.7 wt.% (77 mole % relative to the diol component) cyclohexanedimethanol, with an inherent viscosity of 0.72 dl/g (measured in a 1:1 mixture consisting of phenol and tetrachloroethane at 25 °C) (Eastman Chemical), Glass transition temperature 110°C (determined by DSC)

    Copolyester II: Copolycondensate of terephthalic acid consisting of 48.3 wt.% terephthalic acid, 11.7 wt.% (23 mole % relative to the diol component) 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 40.0 wt.% (77 mole % relative to the diol component) cyclohexanedimethanol, with an inherent viscosity of 0.63 dl/g (measured in a 1:1 mixture consisting of phenol and tetrachloroethane at 25 °C), Glass transition temperature 105°C (determined by DSC)

    TEXIN 970U: commercial aromatic transparent thermoplastic polyether polyurethane with a Shore hardness of 70 D according to DIN EN ISO 868 (Bayer MaterialScience AG)

    MAKROLON 3108: commercial high viscous amorphous, thermoplastic Bisphenol A-Polycarbonat with a Melt Volume Rate (MVR) of 6 g/10min according to ISO 1133 at 300°C and 1,2 kg from Bayer MaterialScience AG; Glass transition temperature 149°C (determined by DSC)

    HYTREL 7246: is a commercial high modulus thermoplastic polyester elastomer grade with nominal Shore hardness according to DIN EN ISO 868 of 72 D from Dupont Company, Wilmington

    POCAN B 1600: is a commercial thermoplastic butylene terephthalate with a Melt Volume Rate (MVR) of 14 g/10min according to ISO 1133 at 260°C and 2,16 kg from Lanxess AG


    Production of the layered structures according to the invention:


    Production of extruded films



    [0098] The film extrusion line that is used for producing the co-extruded film(s) comprises:

    ▪ an extruder with a screw of 60 mm diameter (D) and with a length of 33 D. The screw exhibits a degassing zone;

    ▪ a melt pump;

    ▪ a crosshead;

    ▪ a flat sheet die with a width of 450 mm;

    ▪ a three-roll calender with horizontal roller arrangement, the third roller being capable of swivelling about +/- 45° in relation to the horizontal;

    ▪ a roller conveyor;

    ▪ thickness measurement

    ▪ a device for bilateral application of protective film;

    ▪ a take-off device;

    ▪ a winding machine.



    [0099] The granular material was conveyed out of the dryer into the feed hopper of the extruder. In the plasticising system constituted by the cylinder/screw of the extruder the melting and conveying of the material took place. From the flat sheet die the melt arrived at the calender. On the calender (consisting of three rolls) the definitive shaping and cooling of the film took place. For the purpose of texturing the surfaces of the film, in this connection two polished chromium rollers (for gloss/gloss surfaces) were employed. Subsequently the film was transported through a take-off, the protective film is applied on both sides, then the winding-up of the film took place.

    Example 1 (not according to the invention)



    [0100] With the film extrusion line described above, with a temperature of the main extruder from 240 °C to 260 °C a monolayer film consisting of Copolyester I with a thickness of 760 µm was produced.

    Example 2 (not according to the invention)



    [0101] With the same film extrusion line as in Example 1, with a temperature of the main extruder from 220 °C to 240 °C a monolayer film consisting of ISOPLAST 2530 with a thickness of 750 µm was produced.

    Example 3 (according to the invention)


    Co-extrusion of film



    [0102] The film extrusion line that is used consists of

    ▪ an extruder with a screw of 105 mm diameter (D) and with a length of 41xD. The screw exhibits a degassing zone;

    ▪ a co-extruder for applying the top layer with a screw of length 25 D and with a diameter of 35 mm

    ▪ a crosshead;

    ▪ a special co-extrusion film die with a width of 1500 mm;

    ▪ a three-roll calender with horizontal roller arrangement, the third roller being capable of swivelling about +/- 45° in relation to the horizontal;

    ▪ a roller conveyor;

    ▪ a device for application of protective film on both surfaces;

    ▪ a take-off device;

    ▪ winding machine.



    [0103] The granular material of the base material was supplied to the feed hopper of the main extruder. In the respective plasticising system constituted by cylinder/screw the melting and conveying of the respective material took place. Both material melts were brought together in the co-extrusion nozzle. From the nozzle the melt arrived at the calender. On the roll calender the definitive shaping and cooling of the material take place. For the purpose of structuring the surfaces of the film, in this connection two polished chromium rollers (for gloss/gloss surfaces) were employed. Subsequently the film was transported through a take-off, the protective film is applied on both sides, then the winding-up of the film took place.

    [0104] With this film extrusion line, with a temperature of the main extruder from 220 °C to 240 °C and with a temperature of the co-extruder from 228 °C to 260 °C three-layer films according to the invention with two smooth, glossy sides with a layer thickness of 800 µm were extruded, the copolyester core layer being 650 µm thick and the thermoplastic polyurethane layer on each side being in each instance 75 µm thick.

    Example 4 (according to the invention):



    [0105] In the film extrusion line as in Example 3, instead of Copolyester I the more readily flowing Copolyester II was employed for the purpose of producing the three-layer films.

    [0106] From this, with a temperature of the main extruder from 220 °C to 235 °C and with a temperature of the co-extruder from 227 °C to 260 °C three-layer films according to the invention with two smooth, shiny sides with a layer thickness of 800 µm were extruded, the copolyester core layer being 650 µm thick and the thermoplastic polyurethane layer on each side being in each instance 75 µm thick.

    Example 5 (according to the invention):



    [0107] In the same film extrusion line as in Example 3, a film according to the invention with one glossy surface and one matt surface was extruded.

    [0108] In this connection, for the purpose of structuring the two surfaces of the film a polished chromium roller and a structured silicone-rubber roller were employed. Rubber rollers that are used for the structuring of the surface of the film are described in DE 32 28 002 (or in the equivalent US 4,368,240) held by Nauta Roll Corporation.

    [0109] With a temperature of the main extruder from 220 °C to 235 °C and with a temperature of the co-extruder from 227 °C to 260 °C three-layer films according to the invention with a smooth, glossy side and with a matt side with a layer thickness of 800 µm were extruded, the copolyester core layer being 650 µm thick and the thermoplastic polyurethane layer on each side being in each instance 75 µm thick.

    Example 6 (according to the invention):



    [0110] In the film extrusion line as in Example 3, instead of Copolyester I the blend of 60% by weight MAKROLON 3108 and 40% by weight POCAN B 1600 for the main extruder and TEXIN 970U for the co extruder were employed for the purpose of producing the three-layer films. The TEXIN 970U forms the outer layers, the MAKROLON/POCAN blend the core layer.

    [0111] From this, with a temperature of the main extruder from 260 °C to 270 °C and with a temperature of the co-extruder from 210 °C to 230 °C three-layer films according to the invention with two smooth, shiny sides with a layer thickness of 750 µm were extruded, the copolyester core layer being 550 µm thick and the thermoplastic polyurethane layer on each side being in each instance 100 µm thick.

    Example 7 (according to the invention):



    [0112] In the film extrusion line as in Example 3, instead of Copolyester I the blend of 60% by weight MAKROLON 3108 and 40% by weight POCAN B 1600 for the main extruder and HYTREL 7246 for the co extruder were employed for the purpose of producing the three-layer films. The HYTREL 7246 forms the outer layers, the MAKROLON/POCAN blend the core layer.

    [0113] From this, with a temperature of the main extruder from 260 °C to 270 °C and with a temperature of the co-extruder from 227 °C to 245 °C three-layer films according to the invention with two smooth, shiny sides with a layer thickness of 750 µm were extruded, the copolyester core layer being 550 µm thick and the thermoplastic polyester elastomer layer on each side being in each instance 100 µm thick.

    Example 8 (according to the invention):



    [0114] In the film extrusion line as in Example 3, instead of Copolyester I the blend of 60% by weight MAKROLON 3108 and 40% by weight POCAN B 1600 for the main extruder and ISOPLAST 2530 for the co extruder were employed for the purpose of producing the three-layer films. The ISOPLAST 2530 forms the outer layers, the MAKROLON/POCAN blend the core layer.

    [0115] From this, with a temperature of the main extruder from 260 °C to 270 °C and with a temperature of the co-extruder from 210 °C to 240 °C three-layer films according to the invention with two smooth, shiny sides with a layer thickness of 750 µm were extruded, the copolyester core layer being 550 µm thick and the thermoplastic polyurethane layer on each side being in each instance 100 µm thick.

    Example 9:



    [0116] Method for determining the peel strength of the thermoplastic polyurethane (TPU) layer on the copolyester layer of examples 3 to 5

    Preparation of the specimens:



    [0117] 
    1. 1. Die-cut specimens to 4 inch L x 0.76 inch W (10 mm L x 19.3mm W): Die dimension can vary depending on availability (W: 0.75 ∼ 1 inch, L: minimum 4 inch).
    2. 2. Mark on the side of the TPU layer being tested. Flip the sample to the other side. Scratch a line by a sharp cutter at 7mm from one edge of the specimen.
    3. 3. Gently bend the specimen along the cut line while having the tested TPU layer intact.
    4. 4. Gently start peeling the TPU layer by pulling the small cut portion away from the cut line.
    5. 5. Continue peeling until the peel TPU layer is 13 mm in length. Make sure the TPU layer is peeled uniformly across the whole specimen width.
    6. 6. Cut the other end of the specimen to make the total adhered area be 62 mm in length.

    Example 10:


    Determination of the peel strength


    Method:



    [0118] The determination of the peel strength was carried out following the model of ASTM D 903 98. The specimens, which were prepared in accordance with the method in Example 6, were stored at 50 % relative humidity and 23 °C and subsequently tested under these conditions. The separation rate amounted to 305 mm/min. From the calibration curves the mean value between 5 mm and 25 mm was evaluated.

    [0119] The determination has been carried out at three different positions of the specimen. The following show the calculated average results.

    [0120] For the bottom layer an average load per unit width of 0.76 N/mm for example 3, 0.79 N/mm for example 4 and 0.97 N/mm for example 5 was measured. For the top layer an average load per unit width of 1.13 N/mm for example 3, 0.60 N/mm for example 4 and 1.10 N/mm for example 5 was measured. The results show that the films according to the invention exhibit an excellent adhesion between the copolyester core layer and the TPU outer layers.

    [0121] For the three-layered films according to example 6 to 8 the peel strength between the outer layers and the core layer were so high that no separation without damage of the outer layer was possible, so that also these films according to the invention exhibit an excellent adhesion between the core layer and the outer layers.

    Example 11


    Method for determination of tensile strength



    [0122] The measure of tensile strength was carried out following the model of ASTM D 638. The tensile tests were carried out on a tensile testing machine of the type ZwickZ020/148385. Use was made of tensile test specimens of type 4. For the purpose of evaluation, the mean value of 5 measurements was drawn upon. The specimens were stored at > 48 hours at 50 % relative humidity and 23 °C and subsequently tested under these conditions. The speed of testing amounted to 12.7 mm/min, in the course of the determination of Young's modulus (elastic modulus or modulus of elasticity), 1 mm/min.

    [0123] The determination has been carried out at three different positions of the specimen. The following table show the calculated average results.

    Results:



    [0124] 
    Exampleaverage yield stress (N/mm2)average yield strain (%)average tensile strength (N/mm2)average elongation at break (%)average tensile modulus (N/mm2)
    3 36.0 6.6 54.7 168.7 1233.0
    4 36.3 6.3 53.5 171.6 1246.0
    5 35.7 6.3 56.6 183.4 1249.0
    6 32.4 4.3 40.4 128.8 1069
    7 34.9 4.2 58.4 193.4 1202
    8 39.6 4.2 56.4 180.2 1157


    [0125] The results show that the films according to the invention exhibit an excellent tensile strength and an outstanding tensile modulus.

    Example 12:


    Method for determining the stress relaxation



    [0126] The stress relaxation has been determined according to a modification of ASTM D790:
    • sample dimensions: 51 mm (length) X 21.5 mm (width) X ∼0.8mm (thickness)
    • water soaking of the samples at defined temperature (25 °C or 50°C) before measurement of stress relaxation
    • three-point bending with 5% strain
    • support span: 16 mm

    Results:



    [0127] 
    Water Temperature (°C)MaterialsInitial load (N) (t = 0 hour)Remaining Load (N) (t = 24 hours)% Remaining Load
    25 °C Example 2 (not according to the invention)) 45.8 17.7 39
    Example 3 (according to the invention) 25.7 18.3 71
    Example 6 (according to the invention) 45 26,9 60
    Example 7 (according to the invention) 35,5 21,4 60
    Example 8 (according to the invention) 51,1 24 47
    50 °C Example 2 (not according to the invention)) 39.6 2.05 5
    Example 3 (according to the invention) 20.7 4.5 22
    Example 6 (according to the invention) 32,9 11 33
    Example 7 (according to the invention) 27,4 11,2 41
    Example 8 (according to the invention) 39,7 6,5 16


    [0128] In this connection the values for initial load represent the measured values at the time prior to storage, i.e. at time t = 0, and the values for remaining load represent the measured values at the time after 24 h of storage.

    [0129] The results show that at both storage temperatures the three-layer films according to the invention exhibited a higher remaining load after 24 h storage than the TPU single-layer film from Example 2. In particular for examples 3 and 7 it is the more surprising that - although at both storage temperatures the three- layer film according to the invention exhibited a distinctly lower initial load at the time prior to storage - the force that it was still able to exert after storage after 24 h fell to a considerably slighter extent.

    [0130] Only the samples consisting of the three-layer films according to the invention exhibit a small drop in the tensile modulus during the storage in the wet environment. In addition, the films according to the invention display an outstanding adhesion between the core layers and the other layers.


    Claims

    1. Dental device comprising a multi-layer plastic film, characterised in that

    - it has a core layer A containing at least one polycarbonate or copolycarbonate and/or a polyester or copolyester having a glass transition temperature Tg from 80 °C to 200°C,

    - and this core layer A is located between two outer layers B containing at least one thermoplastic polyurethane and/or polyester or copolyester exhibiting a hardness from 45 Shore D to 85 Shore D,
    wherein glass transition temperatures Tg are determined by means of differential scanning calorimetry (DSC) according to standard DIN EN 61006 at a heating- rate of 20 K/min with definition of Tg as the midpoint temperature (tangent method); and wherein Shore hardness is determined in accordance with DIN EN ISO 868.


     
    2. Dental device according to claim 1, characterised in that it has a core layer
    A containing at least one polyester or copolyester having an inherent viscosity from 0.50 dL/g to 1.20 dL/g, and a glass transition temperature Tg from 80 °C to 200°C,
    wherein inherent viscosity is determined in 60/40 (wt/wt) phenol/ tetrachloroethane at a concentration of 0.5 g/100 ml at 25°C.
     
    3. Dental device according to claim 1 or 2, characterised in that the two outer layers B containing at least one thermoplastic polyurethane exhibiting a hardness from 45 Shore D to 85 Shore D.
     
    4. Dental device according to at least one of Claims 1 to 3, characterised in that

    - it has a core layer A containing at least one copolyester that exhibits residues from

    (a) a dicarboxylic acid component comprising

    i) 70 mole % to 100 mole % terephthalic acid residues,

    ii) 0 mole % to 30 mole % aromatic dicarboxylic acid residues with up to 20 carbon atoms, and

    iii) 0 mole % to 10 mole % aliphatic dicarboxylic acid residues with up to 16 carbon atoms, and

    (b) a diol component comprising

    i) 5 mole % to 50 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues, and

    ii) 50 mole % to 95 mole % 1,4-cyclohexanedimethanol residues,

    wherein the sum of the mole % of residues i) - iii) of the dicarboxylic acid component amounts to 100 mole % and the sum of the mole % of residues i) and ii) of the diol component amounts to 100 mole % and wherein the inherent viscosity of the copolyester amounts to 0.50 dL/g to 1.20 dL/g and the copolyester exhibits a glass transition temperature Tg from 80 °C to 150 °C,

    - and this core layer is located between two outer layers B containing at least one thermoplastic polyurethane, the thermoplastic polyurethane exhibiting a hardness from 45 Shore D to 85 Shore D and being obtainable from

    a) one or more linear polyether diols with mean molecular weights from 500 g/mol to 10,000 g/mol, preferably 500 g/mol to 6000 g/mol, and, on average, in each instance at least 1.8 and at most 3.0, preferably 1.8 to 2.2, Tserevitinov-active hydrogen atoms

    b) one or more organic diisocyanates,

    c) one or more diol chain-extenders with molecular weights from 60 g/mol to 500 g/mol and with, on average, 1.8 to 3.0 Tserevitinov-active hydrogen atoms
    in the presence of

    d) optionally, one or more catalysts
    with addition of

    e) optionally, auxiliary substances and additives,
    wherein the molar ratio of the NCO groups in b) to the groups in a) and c) that are reactive towards isocyanate amounts to 0.85:1 to 1.2:1, preferably 0.9:1 to 1.1:1.


     
    5. Dental device according to at least one of Claims 1 to 4, characterised in that the thermoplastic polyurethane exhibits a hardness from 50 Shore D to 80 Shore D.
     
    6. Dental device according to Claim 4 or 5, characterised in that the polyether diols a) used for producing the thermoplastic polyurethane are selected from one or more polyether diols of the group based on 1,4-butanediol units and/or 1,3-propylene glycol units.
     
    7. Dental device according to at least one of Claims 4 to 6, characterised in that the organic diisocyanate b) used for producing the thermoplastic polyurethane is selected from one or more isocyanates of the group containing 4,4'-diphenylmethane diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate or 1,6-hexamethylene diisocyanate.
     
    8. Dental device according to at least one of Claims 4 to 7, characterised in that the diol chain-extender c) used for producing of the thermoplastic polyurethane is selected from one or more chain-extenders of the group containing 1,4-butanediol, 1,3-propanediol, 1,2-propanediol, 1,2-ethylene glycol, 1,6-hexanediol, 1,4-di(β-hydroxyethyl)hydroquinone or 1,4-di(βhydroxyethyl)bisphenol A.
     
    9. Dental device according to at least one of Claims 4 to 8, characterised in that the thermoplastic polyurethane was produced in the prepolymer process.
     
    10. Dental device according to at least one of Claims 4 to 9, characterised in that the diol component of the copolyester comprises 10 mole % to 35 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues and 65 mole % to 90 mole % 1,4-cyclohexanedimethanol residues, preferably 15 mole % to 35 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues and 65 mole % to 85 mole % 1,4-cyclohexanedimethanol residues, particularly preferably 15 mole % to 30 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues and 70 mole % to 85 mole % 1,4-cyclohexanedimethanol residues, the sum of the mole % of these two components of the diol component amounting to 100 mole %.
     
    11. Dental device according to at least one of Claims 4 to 10, characterised in that the residues from the dicarboxylic acid component of the polyester include 95 mole % to 100 mole % terephthalic acid residues.
     
    12. Dental device according to at least one of Claims 1 to 11, characterised in that the film has been co-extruded.
     
    13. Dental device according to at least one of Claims 1 to 12, characterised in that:

    it has a total thickness from 300 µm to 2000 µm, preferably from 400 µm to 1500 µm, particularly preferably from 500 µm to 1200 µm, and/or

    the core layer A has a layer thickness from 250 µm to 1600 µm, preferably from 350 µm to 1400 µm, particularly preferably from 400 µm to 1000 µm.


     
    14. Dental device according to at least one of Claims 1 to 13, characterised in that the outer layers B each have a layer thickness from 25 µm to 500 µm, preferably from 30 µm to 300 µm, particularly preferably from 50 µm to 200 µm.
     
    15. Dental device according to at least one of Claims 2 to 14, characterised in that:

    the poly- or copolyester exhibits an inherent viscosity from 0.50 dL/g to 0.80 dL/g, and/or

    the poly- or copolyester exhibits a glass transition temperature Tg from 85 °C to 130 °C, preferably from 90 °C to 120 °C.


     
    16. Dental device according to at least one of Claims 1 to 15, wherein said dental device comprises an adhesive force between core layer A and the outer layers B of more than 0.3 N/mm, preferably more than 0.5 N/mm, wherein adhesive force is determined in accordance with ASTM D 903 98.
     
    17. Dental device according to at least one of Claims 1 to 16, wherein said dental device comprises a transmission of visible light from 380 nm to 780 nm of more than 70 %, or preferably of more than 80 %,
    wherein transmission of visible light is determined in accordance with ASTM D 1003.
     
    18. Dental device according to at least one of Claims 1 to 17, wherein said dental device is obtained by thermoforming the multi-layer plastic film into a three dimensionally shaped article.
     
    19. Dental device according to at least one of Claims 1 to 18, characterised in that the dental device comprises a three-layer film consisting of the core layer A between the two outer layers B, wherein:

    said core layer A contains at least one copolyester,

    and said two outer layers B contain at least one thermoplastic polyurethane.


     
    20. Dental device according to claim 1 wherein said core layer A comprises at least one copolyester that exhibits residues from

    (a) a dicarboxylic acid component comprising

    i) 70 mole % to 100 mole % terephthalic acid residues,

    ii) 0 mole % to 30 mole % aromatic dicarboxylic acid residues with up to 20 carbon atoms, and

    iii) 0 mole % to 10 mole % aliphatic dicarboxylic acid residues with up to 16 carbon atoms, and

    (b) a diol component comprising

    i) 5 mole % to 50 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues, and

    ii) 50 mole % to 95 mole % 1,4-cyclohexanedimethanol residues,

    wherein the sum of the mole % of residues i) - iii) of the dicarboxylic acid component amounts to 100 mole % and the sum of the mole % of residues i) and ii) of the diol component amounts to 100 mole %.


     
    21. A method of producing a dental device, the method comprising thermoforming a multi-layer plastic film in the shape of the dental device, wherein the multi-layer plastic film is characterised in that

    - it has a core layer A containing at least one polycarbonate or copolycarbonate and/or a polyester or copolyester having a glass transition temperature Tg from 80 °C to 200°C,

    - and this core layer A is located between two outer layers B containing at least one thermoplastic polyurethane and/or polyester or copolyester exhibiting a hardness from 45 Shore D to 85 Shore,

    wherein glass transition temperature Tg is determined by means of differential scanning calorimetry (DSC) according to standard DIN EN 61006 at a heating- rate of 20 K/min with definition of Tg as the midpoint temperature, and
    wherein Shore hardness is determined in accordance with DIN EN ISO 868.
     


    Ansprüche

    1. Dentalvorrichtung umfassend eine mehrschichtige Kunststofffolie, dadurch gekennzeichnet, dass

    - sie eine Kernschicht A aufweist, die wenigstens ein Polycarbonat oder Copolycarbonat und/oder einen Polyester oder Copolyester mit einer Glasübergangstemperatur Tg von 80 °C bis 200 °C enthält;

    - und sich diese Kernschicht A zwischen zwei äußeren Schichten B befindet, die wenigstens ein thermoplastisches Polyurethan und/oder Polyester oder Copolyester, das bzw. der eine Härte von 45 Shore D bis 85 Shore D aufweist, enthalten;

    wobei Glasübergangstemperaturen Tg mittels dynamischer Differenzkalorimetrie (DSC) gemäß der Norm DIN EN 61006 mit einer Aufheizgeschwindigkeit von 20 K/min bestimmt werden, wobei Tg als Mittelpunktstemperatur definiert ist (Tangentialverfahren); und
    wobei die Shore-Härte gemäß DIN EN ISO 868 bestimmt wird.
     
    2. Dentalvorrichtung gemäß Anspruch 1, dadurch gekennzeichnet, dass sie eine Kernschicht A aufweist, die wenigstens einen Polyester oder Copolyester mit einer logarithmischen Viskositätszahl von 0,50 dl/g bis 1,20 dl/g und einer Glasübergangstemperatur Tg von 80 °C bis 200 °C enthält, wobei die logarithmische Viskositätszahl in Phenol/Tetrachlorethan 60/40 (w/w) mit einer Konzentration von 0,5 g/100 ml bei 25 °C bestimmt wird.
     
    3. Dentalvorrichtung gemäß Anspruch 1 oder 2, dadurch gekennzeichnet, dass die zwei äußeren Schichten B wenigstens ein thermoplastisches Polyurethan, das eine Härte von 45 Shore D bis 85 Shore D aufweist, enthalten.
     
    4. Dentalvorrichtung gemäß wenigstens einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, dass

    - sie eine Kernschicht A aufweist, die wenigstens einen Copolyester enthält, der Reste aufweist von

    (a) einer Dicarbonsäurekomponente umfassend

    i) 70 Mol-% bis 100 Mol-% Terephthalsäureresten,

    ii) 0 Mol-% bis 30 Mol-% aromatischen Dicarbonsäureresten mit bis zu 20 Kohlenstoffatomen und

    iii) 0 Mol-% bis 10 Mol-% aliphatischen Dicarbonsäureresten mit bis zu 16 Kohlenstoffatomen; und

    (b) einer Diolkomponente umfassend

    i) 5 Mol-% bis 50 Mol-% 2,2,4,4-Tetramethyl-1,3-cyclobutandiol-resten und

    ii) 50 Mol-% bis 95 Mol-% 1,4-Cyclohexandimethanolresten;

    wobei die Summe der Molprozente der Reste i) bis iii) der Dicarbonsäurekomponente 100 Mol-% beträgt und die Summe der Molprozente der Reste i) und ii) der Diolkomponente 100 Mol-% beträgt;
    und wobei die logarithmische Viskositätszahl des Copolyesters 0,50 dl/g bis 1,20 dl/g beträgt und der Copolyester eine Glasübergangstemperatur Tg von 80 °C bis 150 °C aufweist;

    - und sich diese Kernschicht zwischen zwei äußeren Schichten B befindet, die wenigstens ein thermoplastisches Polyurethan enthalten, wobei das thermoplastische Polyurethan eine Härte von 45 Shore D bis 85 Shore D aufweist und erhältlich ist aus

    a) einem oder mehreren linearen Polyetherdiolen mit mittleren Molekulargewichten von 500 g/mol bis 10 000 g/mol, vorzugsweise 500 g/mol bis 6000 g/mol, und im Durchschnitt in jedem Fall wenigstens 1,8 und höchstens 3,0, vorzugsweise 1,8 bis 2,2, Zerewitinow-aktiven Wasserstoffatomen;

    b) einem oder mehreren organischen Diisocyanaten;

    c) einem oder mehreren Diol-Kettenverlängerern mit Molekulargewichten von 60 g/mol bis 500 g/mol und mit im Durchschnitt 1,8 bis 3,0 Zerewitinow-aktiven Wasserstoffatomen;
    in Gegenwart von

    d) gegebenenfalls einem oder mehreren Katalysatoren;
    unter Zugabe von

    e) gegebenenfalls Hilfssubstanzen und Additiven;
    wobei das Stoffmengenverhältnis der NCO-Gruppen in b) zu den Gruppen in a) und c), die gegenüber Isocyanat reaktiv sind, 0,85:1 bis 1,2:1, vorzugsweise 0,9:1 bis 1,1:1, beträgt.


     
    5. Dentalvorrichtung gemäß wenigstens einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, dass das thermoplastische Polyurethan eine Härte von 50 Shore D bis 80 Shore D aufweist.
     
    6. Dentalvorrichtung gemäß Anspruch 4 oder 5, dadurch gekennzeichnet, dass die zur Herstellung des thermoplastischen Polyurethans verwendeten Polyetherdiole a) aus einem oder mehreren Polyetherdiolen der Gruppe, die auf 1,4-Butandiol-Einheiten und/oder 1,3-Propylenglycol-Einheiten basiert, ausgewählt sind.
     
    7. Dentalvorrichtung gemäß wenigstens einem der Ansprüche 4 bis 6, dadurch gekennzeichnet, dass das zur Herstellung des thermoplastischen Polyurethans verwendete organische Diisocyanat b) aus einem oder mehreren Isocyanaten der Gruppe, die 4,4'-Diphenylmethandiisocyanat, Isophorondiisocyanat, Dicyclohexylmethan-4,4'-diisocyanat oder 1,6-Hexamethylendiisocyanat enthält, ausgewählt ist.
     
    8. Dentalvorrichtung gemäß wenigstens einem der Ansprüche 4 bis 7, dadurch gekennzeichnet, dass der zur Herstellung des thermoplastischen Polyurethans verwendete Diol-Kettenverlängerer c) aus einem oder mehreren Kettenverlängerern der Gruppe, die 1,4-Butandiol, 1,3-Propandiol, 1,2-Propandiol, 1,2-Ethylenglycol, 1,6-Hexandiol, 1,4-Di(β-hydroxyethyl)hydrochinon oder 1,4-Di(β-hydroxyethyl)bisphenol A enthält, ausgewählt ist.
     
    9. Dentalvorrichtung gemäß wenigstens einem der Ansprüche 4 bis 8, dadurch gekennzeichnet, dass das thermoplastische Polyurethan im Prepolymerverfahren hergestellt wurde.
     
    10. Dentalvorrichtung gemäß wenigstens einem der Ansprüche 4 bis 9, dadurch gekennzeichnet, dass die Diolkomponente des Copolyesters 10 Mol-% bis 35 Mol-% 2,2,4,4-Tetramethyl-1,3-cyclobutandiolreste und 65 Mol-% bis 90 Mol-% 1,4-Cyclohexandimethanolreste, vorzugsweise 15 Mol-% bis 35 Mol-% 2,2,4,4-Tetramethyl-1,3-cyclobutandiolreste und 65 Mol-% bis 85 Mol-% 1,4-Cyclohexandimethanolreste, besonders bevorzugt 15 Mol-% bis 30 Mol-% 2,2,4,4-Tetramethyl-1,3-cyclobutandiolreste und 70 Mol-% bis 85 Mol-% 1,4-Cyclohexandimethanolreste, umfasst, wobei die Summe der Molprozente dieser beiden Komponenten der Diolkomponente 100 Mol-% beträgt.
     
    11. Dentalvorrichtung gemäß wenigstens einem der Ansprüche 4 bis 10, dadurch gekennzeichnet, dass die Reste der Dicarbonsäurekomponente des Polyesters 95 Mol-% bis 100 Mol-% Terephthalsäurereste umfassen.
     
    12. Dentalvorrichtung gemäß wenigstens einem der Ansprüche 1 bis 11, dadurch gekennzeichnet, dass die Folie coextrudiert ist.
     
    13. Dentalvorrichtung gemäß wenigstens einem der Ansprüche 1 bis 12, dadurch gekennzeichnet, dass sie eine Gesamtdicke von 300 µm bis 2000 µm, vorzugsweise von 400 µm bis 1500 µm, besonders bevorzugt von 500 µm bis 1200 µm, aufweist und/oder die Kernschicht A eine Schichtdicke von 250 µm bis 1600 µm, vorzugsweise von 350 µm bis 1400 µm, besonders bevorzugt von 400 µm bis 1000 µm, aufweist.
     
    14. Dentalvorrichtung gemäß wenigstens einem der Ansprüche 1 bis 13, dadurch gekennzeichnet, dass die äußeren Schichten B jeweils eine Schichtdicke von 25 µm bis 500 µm, vorzugsweise von 30 µm bis 300 µm, besonders bevorzugt von 50 µm bis 200 µm, aufweisen.
     
    15. Dentalvorrichtung gemäß wenigstens einem der Ansprüche 2 bis 14, dadurch gekennzeichnet, dass:

    der Polyester oder Copolyester eine logarithmische Viskositätszahl von 0,50 dl/g bis 0,80 dl/g aufweist und/oder

    der Polyester oder Copolyester eine Glasübergangstemperatur Tg von 85 °C bis 130 °C, vorzugsweise von 90 °C bis 120 °C, aufweist.


     
    16. Dentalvorrichtung gemäß wenigstens einem der Ansprüche 1 bis 15, wobei die Dentalvorrichtung eine Klebekraft zwischen Kernschicht A und den äußeren Schichten B von mehr als 0,3 N/mm, vorzugsweise mehr als 0,5 N/mm, umfasst, wobei die Klebekraft gemäß ASTM D 903 98 bestimmt wird.
     
    17. Dentalvorrichtung gemäß wenigstens einem der Ansprüche 1 bis 16, wobei die Dentalvorrichtung eine Durchlässigkeit für sichtbares Licht von 380 nm bis 780 nm von mehr als 70% oder vorzugsweise mehr als 80% umfasst, wobei die Durchlässigkeit für sichtbares Licht gemäß ASTM D 1003 bestimmt wird.
     
    18. Dentalvorrichtung gemäß wenigstens einem der Ansprüche 1 bis 17, wobei die Dentalvorrichtung durch Thermoformen der mehrschichtigen Kunststofffolie zu einem dreidimensional geformten Artikel erhalten wird.
     
    19. Dentalvorrichtung gemäß wenigstens einem der Ansprüche 1 bis 18, dadurch gekennzeichnet, dass die Dentalvorrichtung eine dreischichtige Folie umfasst, die aus der Kernschicht A zwischen den beiden äußeren Schichten B besteht, wobei:

    die Kernschicht A wenigstens einen Copolyester enthält

    und die zwei äußeren Schichten B wenigstens ein thermoplastisches Polyurethan enthalten.


     
    20. Dentalvorrichtung gemäß Anspruch 1, wobei die Kernschicht A wenigstens einen Copolyester umfasst, der Reste aufweist von:

    (a) einer Dicarbonsäurekomponente umfassend

    i) 70 Mol-% bis 100 Mol-% Terephthalsäureresten,

    ii) 0 Mol-% bis 30 Mol-% aromatischen Dicarbonsäureresten mit bis zu 20 Kohlenstoffatomen und

    iii) 0 Mol-% bis 10 Mol-% aliphatischen Dicarbonsäureresten mit bis zu 16 Kohlenstoffatomen; und

    (b) einer Diolkomponente umfassend

    i) 5 Mol-% bis 50 Mol-% 2,2,4,4-Tetramethyl-1,3-cyclobutandiol-resten und

    ii) 50 Mol-% bis 95 Mol-% 1,4-Cyclohexandimethanolresten,

    wobei die Summe der Molprozente der Reste i) bis iii) der Dicarbonsäurekomponente 100 Mol-% beträgt und die Summe der Molprozente der Reste i) und ii) der Diolkomponente 100 Mol-% beträgt.
     
    21. Verfahren zur Herstellung einer Dentalvorrichtung, wobei das Verfahren das Thermoformen einer mehrschichtigen Kunststofffolie in die Form der Dentalvorrichtung umfasst,
    wobei die mehrschichtige Kunststofffolie dadurch gekennzeichnet ist, dass

    - sie eine Kernschicht A aufweist, die wenigstens ein Polycarbonat oder Copolycarbonat und/oder einen Polyester oder Copolyester mit einer Glasübergangstemperatur Tg von 80 °C bis 200 °C enthält;

    - und sich diese Kernschicht A zwischen zwei äußeren Schichten B befindet, die wenigstens ein thermoplastisches Polyurethan und/oder Polyester oder Copolyester, das bzw. der eine Härte von 45 Shore D bis 85 Shore D aufweist, enthalten;

    wobei die Glasübergangstemperatur Tg mittels dynamischer Differenzkalorimetrie (DSC) gemäß der Norm DIN EN 61006 mit einer Aufheizgeschwindigkeit von 20 K/min bestimmt wird, wobei Tg als Mittelpunktstemperatur definiert ist; und
    wobei die Shore-Härte gemäß DIN EN ISO 868 bestimmt wird.
     


    Revendications

    1. Dispositif dentaire comprenant un film en matière plastique à multiples couches, caractérisé en ce que :

    - il comporte une couche d'âme A qui contient au moins un polycarbonate ou copolycarbonate et/ou un polyester ou copolyester qui présente(nt) une température de transition vitreuse Tg qui est comprise entre 80 °C et 200 °C ;

    - et cette couche d'âme A est localisée entre deux couches externes B qui contiennent au moins un polyuréthane et/ou polyester ou copolyester thermoplastique qui présente(nt) une dureté qui est comprise entre 45 Shore D et 85 Shore D ;

    dans lequel les températures de transition vitreuse Tg sont déterminées au moyen d'une calorimétrie différentielle à balayage (DSC) conformément au standard DIN EN 61006 à une vitesse de chauffage de 20 K/min, la température de transition vitreuse Tg étant définie en tant que température de point milieu (procédé par les tangentes) ; et
    dans lequel la dureté Shore est déterminée conformément à DIN EN ISO 868.
     
    2. Dispositif dentaire selon la revendication 1, caractérisé en ce qu'il comporte une couche d'âme A qui contient au moins un polyester ou copolyester qui présente une viscosité inhérente qui est comprise entre 0,50 dL/g et 1,20 dL/g, et une température de transition vitreuse Tg qui est comprise entre 80 °C et 200 °C ;
    dans lequel la viscosité inhérente est déterminée dans un mélange de phénol/tétrachloroéthane à 60/40 (en poids/en poids) selon une concentration de 0,5 g/100 ml à 25 °C.
     
    3. Dispositif dentaire selon la revendication 1 ou 2, caractérisé en ce que les deux couches externes B contiennent au moins un polyuréthane thermoplastique qui présente une dureté qui est comprise entre 45 Shore D et 85 Shore D.
     
    4. Dispositif dentaire selon au moins l'une des revendications 1 à 3, caractérisé en ce que :

    - il comporte une couche d'âme A qui contient au moins un copolyester qui présente des résidus de

    (a) un composant d'acide dicarboxylique qui comprend :

    i) de 70 % en pourcentage molaire à 100 % en pourcentage molaire de résidus d'acide téréphtalique ;

    ii) de 0 % en pourcentage molaire à 30 % en pourcentage molaire de résidus d'acide dicarboxylique aromatique avec jusqu'à 20 atomes de carbone ; et

    iii) de 0 % en pourcentage molaire à 10 % en pourcentage molaire de résidus d'acide dicarboxylique aliphatique avec jusqu'à 16 atomes de carbone ; et

    (b) un composant de diol qui comprend :

    i) de 5 % en pourcentage molaire à 50 % en pourcentage molaire de résidus de 2,2,4,4-tétraméthyl-1,3-cyclobutanediol ; et

    ii) de 50 % en pourcentage molaire à 95 % en pourcentage molaire de résidus de 1,4-cyclohexanediméthanol ;

    dans lequel la somme des pourcentages molaires des résidus i) à iii) du composant d'acide dicarboxylique est égale à 100 % en pourcentage molaire et la somme des pourcentages molaires des résidus i) et ii) du composant de diol est égale à 100 % en pourcentage molaire ;
    et dans lequel la viscosité inhérente du copolyester est comprise entre 0,50 dL/g et 1,20 dL/g et le copolyester présente une température de transition vitreuse Tg qui est comprise entre 80 °C et 150 °C ;

    - et cette couche d'âme est localisée entre deux couches externes B qui contiennent au moins un polyuréthane thermoplastique, le polyuréthane thermoplastique présentant une dureté qui est comprise entre 45 Shore D et 85 Shore D et pouvant être obtenu à partir de :

    a) un ou plusieurs diol(s) de polyéther linéaire(s) qui présente(nt) des poids moléculaires moyens qui sont compris entre 500 g/mol et 10 000 g/mol, de préférence entre 500 g/mol et 6000 g/mol, et qui comprend/comprennent, en moyenne, dans chaque cas, au moins 1,8 et au plus 3,0, de préférence entre 1,8 et 2,2 atomes d'hydrogène actifs selon Tserevitinov ;

    b) un ou plusieurs diisocyanate(s) organique(s) ;

    c) un ou plusieurs extenseur(s) de chaîne diol qui présente(nt) des poids moléculaires qui sont compris entre 60 g/mol et 500 g/mol, et qui comprend/comprennent, en moyenne, de 1,8 à 3,0 atomes d'hydrogène actifs selon Tserevitinov
    en présence de

    d) en option, un ou plusieurs catalyseur(s)
    moyennant l'ajout

    e) en option, de substances auxiliaires et d'additifs,
    dans lequel le rapport molaire des groupes NCO dans b) sur les groupes dans a) et dans c) qui sont réactifs en relation avec l'isocyanate est compris entre 0,85:1 et 1,2:1, de préférence entre 0,9:1 et 1,1:1.


     
    5. Dispositif dentaire selon au moins l'une des revendications 1 à 4, caractérisé en ce que le polyuréthane thermoplastique présente une dureté qui est comprise entre 50 Shore D et 80 Shore D.
     
    6. Dispositif dentaire selon la revendication 4 ou 5, caractérisé en ce que les diols de polyéther a) qui sont utilisés pour produire le polyuréthane thermoplastique sont sélectionnés parmi un ou plusieurs diol(s) de polyéther du groupe qui est basé sur les unités de 1,4-butanediol et/ou les unités de 1,3-propylène glycol.
     
    7. Dispositif dentaire selon au moins l'une des revendications 4 à 6, caractérisé en ce que le diisocyanate organique b) qui est utilisé pour produire le polyuréthane thermoplastique est sélectionné parmi un ou plusieurs isocyanate(s) du groupe qui contient le diisocyanate de 4,4'-diphénylméthane, le diisocyanate d'isophorone, le dicyclohexylméthane-4,4'-diisocyanate ou le diisocyanate de 1,6-hexaméthylène.
     
    8. Dispositif dentaire selon au moins l'une des revendications 4 à 7, caractérisé en ce que l'extenseur de chaîne diol c) qui est utilisé pour produire le polyuréthane thermoplastique est sélectionné parmi un ou plusieurs extenseur(s) de chaîne du groupe qui contient le 1,4-butanediol, le 1,3-propanediol, le 1,2-propanediol, le 1,2-éthylène glycol, le 1,6-hexanediol, le 1,4-di(β-hydroxyéthyl)hydroquinone ou le 1,4- di(β-hydroxyéthyl)bisphénol A.
     
    9. Dispositif dentaire selon au moins l'une des revendications 4 à 8, caractérisé en ce que le polyuréthane thermoplastique a été produit lors du processus de prépolymérisation.
     
    10. Dispositif dentaire selon au moins l'une des revendications 4 à 9, caractérisé en ce que le composant de diol du copolyester comprend de 10 % en pourcentage molaire à 35 % en pourcentage molaire de résidus de 2,2,4,4-tétraméthyl-1,3-cyclobutanediol et de 65 % en pourcentage molaire à 90 % en pourcentage molaire de résidus de 1,4-cyclohexanediméthanol, de préférence de 15 % en pourcentage molaire à 35 % en pourcentage molaire de résidus de 2,2,4,4-tétraméthyl-1,3-cyclobutanediol et de 65 % en pourcentage molaire à 85 % en pourcentage molaire de résidus de 1,4-cyclohexanediméthanol, de façon particulièrement préférable, de 15 % en pourcentage molaire à 30 % en pourcentage molaire de résidus de 2,2,4,4-tétraméthyl-1,3-cyclobutanediol et de 70 % en pourcentage molaire à 85 % en pourcentage molaire de résidus de 1,4-cyclohexanediméthanol, la somme des pourcentages molaires de ces deux composants du composant de diol étant égale à 100 % en pourcentage molaire.
     
    11. Dispositif dentaire selon au moins l'une des revendications 4 à 10, caractérisé en ce que les résidus qui proviennent du composant d'acide dicarboxylique du polyester incluent de 95 % en pourcentage molaire à 100 % en pourcentage molaire de résidus d'acide téréphtalique.
     
    12. Dispositif dentaire selon au moins l'une des revendications 1 à 11, caractérisé en ce que le film a été co-extrudé.
     
    13. Dispositif dentaire selon au moins l'une des revendications 1 à 12, caractérisé en ce que :
    il présente une épaisseur totale qui est comprise entre 300 µm et 2000 µm, de préférence entre 400 µm et 1500 µm, de façon particulièrement préférable, entre 500 µm et 1200 µm, et/ou la couche d'âme A présente une épaisseur de couche qui est comprise entre 250 µm et 1600 µm, de préférence entre 350 µm et 1400 µm, de façon particulièrement préférable, entre 400 µm et 1000 µm.
     
    14. Dispositif dentaire selon au moins l'une des revendications 1 à 13, caractérisé en ce que les couches externes B présentent chacune une épaisseur de couche qui est comprise entre 25 µm et 500 µm, de préférence entre 30 µm et 300 µm, de façon particulièrement préférable, entre 50 µm et 200 µm.
     
    15. Dispositif dentaire selon au moins l'une des revendications 2 à 14, caractérisé en ce que :

    le polyester ou copolyester présente une viscosité inhérente qui est comprise entre 0,50 dL/g et 0,80 dL/g ; et/ou

    le polyester ou copolyester présente une température de transition vitreuse Tg qui est comprise entre 85 °C et 130 °C, de préférence entre 90 °C et 120 °C.


     
    16. Dispositif dentaire selon au moins l'une des revendications 1 à 15, dans lequel ledit dispositif dentaire présente une force d'adhérence entre la couche d'âme A et les couches externes B qui est supérieure à 0,3 N/mm, de préférence supérieure à 0,5 N/mm, dans lequel la force d'adhérence est déterminée conformément à ASTM D 903 98.
     
    17. Dispositif dentaire selon au moins l'une des revendications 1 à 16, dans lequel ledit dispositif dentaire présente une transmission de la lumière visible entre 380 nm et 780 nm qui est supérieure à 70 % ou de préférence, supérieure à 80 %,
    dans lequel la transmission de la lumière visible est déterminée conformément à ASTM D 1003.
     
    18. Dispositif dentaire selon au moins l'une des revendications 1 à 17, dans lequel ledit dispositif dentaire est obtenu par thermoformage du film en matière plastique à multiples couches selon un article conformé en trois dimensions.
     
    19. Dispositif dentaire selon au moins l'une des revendications 1 à 18, caractérisé en ce que le dispositif dentaire comprend un film à trois couches qui est constitué par la couche d'âme A entre les deux couches externes B, dans lequel :

    ladite couche d'âme A contient au moins un copolyester ;

    et lesdites deux couches externes B contiennent au moins un polyuréthane thermoplastique.


     
    20. Dispositif dentaire selon la revendication 1, dans lequel ladite couche d'âme A comprend au moins un copolyester qui présente des résidus qui proviennent de

    (a) un composant d'acide dicarboxylique qui comprend :

    i) de 70 % en pourcentage molaire à 100 % en pourcentage molaire de résidus d'acide téréphtalique ;

    ii) de 0 % en pourcentage molaire à 30 % en pourcentage molaire de résidus d'acide dicarboxylique aromatique avec jusqu'à 20 atomes de carbone ; et

    iii) de 0 % en pourcentage molaire à 10 % en pourcentage molaire de résidus d'acide dicarboxylique aliphatique avec jusqu'à 16 atomes de carbone ; et

    (b) un composant de diol qui comprend :

    i) de 5 % en pourcentage molaire à 50 % en pourcentage molaire de résidus de 2,2,4,4-tétraméthyl-1,3-cyclobutanediol ; et

    ii) de 50 % en pourcentage molaire à 95 % en pourcentage molaire de résidus de 1,4-cyclohexanediméthanol ;
    dans lequel la somme des pourcentages molaires des résidus i) à iii) du composant d'acide dicarboxylique est égale à 100 % en pourcentage molaire et la somme des pourcentages molaires des résidus i) et ii) du composant de diol est égale à 100 % en pourcentage molaire.


     
    21. Procédé de fabrication d'un dispositif dentaire, le procédé comprenant :

    le thermoformage d'un film en matière plastique à multiples couches selon la forme du dispositif dentaire, dans lequel le film en matière plastique à multiples couches est caractérisé en ce que :

    - il comporte une couche d'âme A qui contient au moins un polycarbonate ou copolycarbonate et/ou un polyester ou copolyester qui présente(nt) une température de transition vitreuse Tg qui est comprise entre 80 °C et 200 °C ;

    - et cette couche d'âme A est localisée entre deux couches externes B qui contiennent au moins un polyuréthane et/ou polyester ou copolyester thermoplastique qui présente(nt) une dureté qui est comprise entre 45 Shore D et 85 Shore D ;

    dans lequel les températures de transition vitreuse Tg sont déterminées au moyen d'une calorimétrie différentielle à balayage (DSC) conformément au standard DIN EN 61006 à une vitesse de chauffage de 20 K/min, la température de transition vitreuse Tg étant définie en tant que température de point milieu ; et

    dans lequel la dureté Shore est déterminée conformément à DIN EN ISO 868.


     






    Cited references

    REFERENCES CITED IN THE DESCRIPTION



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    Patent documents cited in the description




    Non-patent literature cited in the description