(19)
(11)EP 1 863 861 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
11.05.2011 Bulletin 2011/19

(21)Application number: 06723663.8

(22)Date of filing:  17.03.2006
(51)International Patent Classification (IPC): 
C08G 63/16(2006.01)
C08L 67/02(2006.01)
(86)International application number:
PCT/EP2006/002674
(87)International publication number:
WO 2006/097356 (21.09.2006 Gazette  2006/38)

(54)

BIODEGRADABLE ALIPHATIC-AROMATIC POLYESTER

BIOLOGISCH ABBAUBARER ALIPHATISCH-AROMATISCHER POLYESTER

POLYESTER ALIPHATIQUE/AROMATIQUE BIODEGRADABLE


(84)Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR

(30)Priority: 18.03.2005 IT MI20050452

(43)Date of publication of application:
12.12.2007 Bulletin 2007/50

(73)Proprietor: NOVAMONT S.p.A.
28100 Novara (IT)

(72)Inventors:
  • BASTIOLI, Catia
    I-28100 Novara (IT)
  • MILIZIA, Tiziana
    I-28100 Novara (IT)
  • FLORIDI,Giovanni
    I-28100 Novara (IT)
  • SCAFFIDI LALLARO, Andrea
    I-28887 Omegna (VB) (IT)
  • CELLA, Gian Domenico
    I-28100 Novara (IT)
  • TOSIN, Maurizio
    I-13037 Serravalle Sesia (VC) (IT)

(74)Representative: Zanoli, Enrico et al
Zanoli & Giavarini S.r.l. Via Melchiorre Gioia, 64
20125 Milano
20125 Milano (IT)


(56)References cited: : 
US-A- 4 398 022
US-B1- 6 458 858
US-A- 5 661 193
  
     
    Remarks:
    The file contains technical information submitted after the application was filed and not included in this specification
     
    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 present invention relates to a biodegradable aliphatic-aromatic (AAPE) polyester obtained from an aliphatic acid at least 50% of which is brassylic acid , at least a polyfunctional aromatic acids and at least a dialcohol, as well as to mixtures of said polyesters with other biodegradable polymers both of natural origin and of synthetic origin.

    [0002] Biodegradable aliphatic-aromatic polyesters obtained from dicarboxylic acids and dialcohols are known in the literature and are commercially available. The presence of the aromatic component in the polyester chain is important to obtain polymers with sufficiently high melting points and with adequate crystallization rates.

    [0003] Although polyesters of this sort are currently commercially available, the amount of aromatic acid in the chain is typically lower than 49% since the above said threshold, the percentage of biodegradation of the polyesters decreases significantly above said threshold.

    [0004] It is reported in the literature (Muller et al., Angew. Chem., Int., Ed. (1999), 38, pp. 1438-1441) that copolymers of the polybutylene adipate-co-terephthalate type with a molar fraction of terephthalate of 42 mol%, biodegrade completely to form compost in twelve weeks, whereas products with 51 mol% of molar fraction of terephthalate show a percentage of biodegradation of less than 40%. This different behaviour was attributed to the formation of a higher number of butylene terephthalate sequences with a length greater than or equal to 3, which are less easily biodegradable.

    [0005] If it were possible to maintain suitable biodegradation properties, an increase in the percentage of aromatic acid in the chain would, however, be desirable in so far as it would enable an increase in the melting point of the polyester, an increase in, or at least a maintenance of, important mechanical properties, such as ultimate strength and elastic modulus, and would moreover enable an increase in the crystallization rate of the polyester, thereby improving its industrial processability.

    [0006] A further drawback of biodegradable aliphatic-aromatic polyesters that are currently commercially available is represented by the fact that the monomers of which they are constituted come from non-renewable sources, thereby maintaining a significant environmental impact associated to the production of such polyesters despite their biodegradability. They have far more energy content than LDPE and HDPE particularly in the presence of adipic acid. On the other hand, the use of monomers of vegetal origin would contribute to the reduction of emission of CO2 in the atmosphere and to the reduction in the use of monomers derived from non-renewable resources.

    [0007] U.S. Patent 4,966,959 discloses certain copolyesters comprising from 60 to 75% mol of terephtalic acid, 25 to 40% mol of a carboxylic aliphatic or cycloaliphatic acid, and a glycol component. The inherent viscosity of such polyesters is from about 0.4 to about 0.6, rendering the polyesters useful as adhesives but unsuitable for many other applications.

    [0008] U.S. Patent 4,398,022 discloses copolyesters comprising terephtalic acid and 1,12-dodecanedioic acid and a glycol component comprising 1,4-cyclohexanedimethanol. The acid component may optionally include one or more acids conventionally used in the production of polyesters, but the examples show that 1,12-dodecanedioic acid must be present for the polyesters to have the desired melt strength.

    [0009] U.S. Patent 5,559,171 discloses binary blends of cellulose esters and aliphatic-aromatic copolyesters. The AAPE component of such blends comprises a moiety derived from a C2 - C14 aliphatic diacid which can range from 30 to 95 % mol in the copolymer, a moiety derived from an aromatic acid which can range from 70 to 5 % mol in the copolymer. Certain AAPEs disclosed in this document do not require blending and are useful in film application. They comprise a moiety derived from a C2-C10 aliphatic diacid which can range from 95 to 35 % mol in the copolymer, and a moiety derived from an aromatic acid which can range from 5 to 65 % mol in the copolymer.

    [0010] DE-A-195 08 737 discloses biodegradable AAPEs comprising terephtalic acid, an aliphatic diacid and a diol component. The weight average molecular weight Mw of such AAPEs is always very low (maximum 51000 g/mol), so that their industrial applicability is limited.

    [0011] It is therefore the overall object of the present invention to disclose an improved AAPE and blends containing the same.

    [0012] In fact, the present invention concerns a biodegradable aliphatic/aromatic copolyester (AAPE) comprising:
    1. A) an acid component comprising repeating units of:
      1. 1) 49 to 63 mol %, preferably 50 to 60 mol %, of an aromatic dicarboxylic acid;
      2. 2) 51 to 37 mol %, preferably 50 to 40 mol %, of an aliphatic acid, at least 50% of which is brassylic acid ;
    2. B) at least one diol component;
      said AAPE being disintegrated according to the Standard ISO 20200 in 90 days and having:
      • a density of less than or equal to 1.18 g/cc, preferably less than 1.17 g/cc;
      • a number average molecular weight Mn of 40,000 - 140,000;
      • an inherent viscosity of 0.8 - 1.5.


    [0013] By "polyfunctional aromatic acids" for the purposes of the present invention are meant aromatic dicarboxylic compounds of the phthalic-acid type and their esters, preferably terephthalic acid.

    [0014] The content of aromatic dicarboxylic acid in the biodegradable polyesters according to the claims of the present invention is between 49-63 mol% and more preferably 50 mol% and 60 mol% with respect to the total molar content of the dicarboxylic acids.

    [0015] The molecular weight Mn of the polyester according to the present invention is between 40 000 and 140 000. The polydispersity index Mw / Mn determined by means of gel-permeation chromatography (GPC) is between 1.7 and 2.6, preferably between 1.8 and 2.5.

    [0016] Examples of diols according to the present invention are 1,2-ethandiol, 1,2-propandiol, 1,3-propandiol, 1,4-butandiol, 1,5-pentandiol, 1,6-hexandiol, 1,7-heptandiol, 1,8-octandiol, 1,9-nonandiol, 1,10-decandiol, 1,11-undecandiol, 1,12-dodecandiol, 1,13-tridecandiol, 1,4-cyclohexandimethanol, propylene glycol, neo-pentyl glycol, 2-methyl-1,3-propandiol, dianhydrosorbitol, dianhydromannitol, dianhydroiditol, cyclohexandiol, and cyclohexan-methandiol. Particularly preferred are diols of the C2 - C10 type. Even more particularly preferred are the C2 - C4 diols. Butandiol is the most preferred one.

    [0017] The polyester according to the invention is rapidly crystallisable and has a crystallization temperature Tc higher than 35° C, preferably higher than 40° C and more preferably higher than 50°C.

    [0018] The polyesters according to the invention have an inherent viscosity (measured with Ubbelhode viscosimeter for solutions in CHCl3 of a concentration of 0.2 g/dl at 25°C) of between 0.8 dl/g and 1.5 dl/g, preferably between 0.83 dl/g and 1.3 dl/g and even more preferably between 0.85 dl/g and 1.2 dl/g.

    [0019] The Melt Flow Rate (MFR) of the polyesters according to the invention, in the case of use for applications typical of plastic materials (such as, for example, bubble filming, injection moulding, foams, etc.), is between 0.5 and 100 g/10 min, preferably between 1.5 - 70 g/10 min, more preferably between 2.0 and 50 g/10 min (measurement made at 190°C/2.16 kg according to the ASTM D1238 standard).

    [0020] The polyesters have a density measured with a Mohr-Westphal weighing machine of less than 1.25 g/cm3, preferably less than 1.22 g/cm3 and even more preferably less than 1.20 g/cm3.

    [0021] Surprisingly the polyester according to the present invention shows a Energy at break higher than 100 MJ/m2.

    [0022] The polyester according to the present invention shows also a Elmendorf tear strength (determined according to the standard ASTM D1922-89 and measured on blown film filmed with a blowing ratio of 2 - 3 and a draw down ratio of 7 - 14) higher than 100 N/mm in the cross direction, higher than 20 N/mm in the longitudinal direction and higher than 60 N/mm for the quantity



    [0023] The aliphatic acid A2 which can be different from brassylic acid can comprise or consist of at least one hydroxy acid or one dicarboxylic acid different from brassylic acid, such as sebacic or azelaic acid, in an amount of up to 50% mol, preferably 30 mol%, with respect to the total molar content of aliphatic acid.

    [0024] Examples of suitable hydroxy acids are glycolic acid, hydroxybutyric acid, hydroxycaproic acid, hydroxyvaleric acid, 7-hydroxyheptanoic acid, 8-hydroxycaproic acid, 9-hydroxynonanoic acid, lactic acid or lactide. The hydroxy acids can be inserted in the chain as such, or else can also be previously made to react with diacids or dialcohols. The hydroxy acid units can be inserted randomly in the chain or can form blocks of adjacent units.

    [0025] In the process of preparation of the copolyester according to the invention one or more polyfunctional molecules, in amounts of between 0.02 - 3.0 mol% preferably between 0.1 mol% and 2.5 with respect to the amount of dicarboxylic acids (as well as to the possible hydroxy acids), can advantageously be added in order to obtain branched products. Examples of these molecules are glycerol, pentaerythritol, trimethylol propane, citric acid, dipentaerythritol, monoanhydrosorbitol, monohydromannitol, epoxidized oils such as epoxidized soybean oil, epoxidized linseed oil and so on, dihydroxystearic acid, itaconic acid and so on.

    [0026] Although the polymers according to the present invention reach high levels of performance without any need to add chain extenders such as di and/or poly isocyanates and isocyanurates, di and/or poly epoxides, bis-oxazolines or poly carbodimides or divinylethers it is in any case possible to modify the properties thereof as the case may require.

    [0027] Generally such additives are used in percentages comprised between 0.05 - 2.5%, preferably 0.1 - 2.0%. In order to improve the reactivity of such additives, specific catalysts can be used such as for example zinc stearates (metal salts of fatty acids) for poly epoxides.

    [0028] The increase in the molecular weight of the polyesters can advantageously be obtained, for example, by addition of various organic peroxides during the process of extrusion. The increase in molecular weight of the biodegradable polyesters can be easily detected by observing the increase in the values of viscosity following upon treatment of the polyesters with peroxides.

    [0029] In case of use of the polyester according to the present invention for the production of films, the addition of the above mentioned chain extenders according to the teaching of EP 1 497 370 results in a production of a gel fraction lower than 4.5% w/w with respect to the polyester. In this connection the content of EP 1 497 370 has to be intended as incorporated by reference in the present description.

    [0030] The polyesters according to the invention present properties and values of viscosity that render them suitable for use, by appropriately modulating the relative molecular weight, in numerous practical applications, such as films, injection-moulded products, extrusion-coating products, fibres, foams, thermoformed products, extruded profiles and sheets, extrusion blow molding, injection blow molding, rotomolding, stretch blow molding etc.

    [0031] In case of films, production technologies like film blowing, casting, coextrusion can be used. Moreover such films can be subject to biorientation in line or after film production. The films can be also oriented through stretching in one direction with a stretching ratio from 1:2 up to 1:15, more preferably from 1:2,2 up to 1:8. It is also possible that the stretching is obtained in presence of an highly filled material with inorganic fillers. In such a case, the stretching can generate microholes and the so obtained film can be particularly suitable for hygiene applications.

    [0032] In particular, the polyesters according to the invention are suitable for the production of:
    • films, whether one-directional or two-directional, and multilayer films with other polymeric materials;
    • films for use in the agricultural sector as mulching films;
    • cling films (extensible films) for foodstuffs, for bales in the agricultural sector and for wrapping of refuse;
    • shrink film such as for example for pallets, mineral water, six pack rings, and so on;
    • bags and liners for collection of organic matter, such as collection of refuse from foodstuffs, and for gathering mowed grass and yard waste;
    • thermoformed single-layer and multilayer packaging for foodstuffs, such as for example containers for milk, yoghurt, meat, beverages, etc.;
    • coatings obtained with the extrusion-coating technique;
    • multilayer laminates with layers of paper, plastic materials, aluminium, metallized films;
    • foamed or foamable beads for the production of pieces formed by sintering;
    • foamed and semi-foamed products including foamed blocks made up of pre-foamed particles;
    • foamed sheets, thermoformed foamed sheets, containers obtained therefrom for the packaging of foodstuffs;
    • containers in general for fruit and vegetables;
    • composites with gelatinized, destructured and/or complexed starch, natural starch, flours, other fillers of natural, vegetal or inorganic origin;
    • fibres, microfibres, composite fibres with a core constituted by rigid polymers, such as PLA, PET, PTT, etc. and an external shell made with the material according to the invention, dablens composite fibres, fibres with various sections (from round to multilobed), flaked fibres, fabrics and non-woven fabrics or spun-bonded or thermobonded fabrics for the sanitary sector, the hygiene sector, the agricultural sector, georemediation, landscaping and the clothing sector.


    [0033] The polyesters according to the invention can moreover be used in blends, obtained also by reactive extrusion, whether with polyesters of the same type (such as aliphatic/aromatic copolyester as for example polybutylene terephthalate adipate PBTA, polybutylene terephthalate succinate PBTS and polybutylene terephthalate glutarate PBTG) or with other biodegradable polyesters (for example, polylactic acid, poly-e-caprolactone, polyhydroxybutyrates, such as poly-3-hydroxybutyrates, poly-4-hydroxybutyrates and polyhydroxybutyrate-valerate, polyhydroxybutyrate-propanoate, polyhydroxybutyrate-hexanoate, polyhydroxybutyrate-decanoate, polyhydroxybutyrate-dodecanoate, polyhydroxybutyrate-hexadecanoate, polyhydroxybutyrate-octadecanoate, and polyalkylene succinates and their copolymers with adipic acid, lactic acid or lactide and caprolacton and their combinations), or other polymers different from polyesters.

    [0034] Mixtures of polyesters with polylactic acid are particularly preferred.

    [0035] The polyesters according to the invention can also be used in blends with polymers of natural origin, such as for example starch, cellulose, chitosan, alginates, natural rubbers or natural fibers (such as for example jute, kenaf, hemp). The starches and celluloses can be modified, and amongst these starch or cellulose esters with a degree of substitution of between 0.2 and 2.5, hydroxypropylated starches, and modified starches with fatty chains may, for example, be mentioned. Preferred esters are acetates, propionates, butyrrates and their combinations. Starch can moreover be used both in its destructured form and in its gelatinized form or as filler.

    [0036] Mixtures of the AAPE according to the invention with starch are particularly preferred.

    [0037] Mixtures of the AAPE according to the present invention with starch can form biodegradable polymeric compositions with good resistance to ageing and to humidities. In these compositions, which comprise thermoplastic starch and a thermoplastic polymer incompatible with starch, starch constitutes the dispersed phase and the AAPE thermoplastic polymer constitutes the continuous phase. In this connection the content of EP 947 559 has to be intended as incorporated by reference in the present description.

    [0038] The polymeric compositions can maintain a high tear strength even in conditions of low humidity. Such characteristic is obtained when starch is in the form of a dispersed phase with an average dimension lower than 1 µm. The preferred average numeral size of the starch particles is between 0,1 and 0,5 microns and more than 80% of the particles have a size of less than 1 micron.

    [0039] Such characteristics can be achieved when the water content of the composition during mixing of the components is preferably kept between 1 and 15%. It is, however, also possible to operate with a content of less than 1% by weight, in this case, starting with predried and pre-plasticized starch.

    [0040] It could be useful also to degrade starch at a low molecular weight before or during compounding with the polyesters of the present invention in order to have in the final material or finished product a starch inherent viscosity between 1 and 0,2dl/g, preferably between 0,6 and 0,25dl/g, more preferably between 0,55 and 0,3 dl/g.

    [0041] Destructurized starch can be obtained before of during mixing with the AAPE of the present invention in presence of plasticizers such as water, glycerol, di and polyglycerols, ethylene or propylene glycol, ethylene and propylene diglycol, polyethylene glycol, polypropylenglycol, 1,2 propandiol, trymethylol ethane, trimethylol propane, pentaerytritol, dipentaerytritol, sorbitol, erytritol, xylitol, mannitol, sucrose, 1,3 propandiol, 1,2, 1,3, 1,4 buthandiol, 1,5 pentandiol, 1,6, 1,5 hexandiol, 1,2,6, 1,3,5-hexantriol , neopentyl glycol, and polyvinyl alcohol prepolymers and polymers, polyols acetates, ethoxylates and propoxylates, particularly sorbitol ethoxylate, sorbitol acetate, and pentaerytritol acetate. The quantity of high boiling point plasticizers (plasticizers different from water) used are generally from 0 to 50%, preferably from 10 to 30% by weight, relative to starch.

    [0042] Water can be used as a plasticizer in combination with high boiling point plasticizers or alone during the plastification phase of starch before or during the mixing of the composition and can be removed at the needed level by degassing in one or more steps during extrusion. Upon completion of the plastification and mixing of the components, the water is removed by degassing to give a final content of about 0,2-3% by weight.

    [0043] Water as well as high-boiling point plasticizers modify the viscosity of the starch phase and affect the rheological properties of the starch/polymer system, helping to determine the dimensions of the dispersed particles. Compatibilizers can be also added to the mixture. They can belong to the following classes:
    • Additives such as esters which have hydrophilic/lipophilic balance index values (HLB) greater than 8 and which are obtained from polyols and from mono or polycarboxylic acids with dissociation constants pK lower than 4,5 (the value relates to pK of the first carboxyl group in the case of polycarboxylic acids).
    • Esters with HLB values of between 5,5 and 8, obtained from polyols and from mono or polycarboxylic acids with less than 12 carbon atoms and with pK values greater than 4,5 (this value relates to the pK of the first carboxylic group in the case of polycarboxylic acids).
    • Esters with HLB values lower than 5,5 obtained from polyols and from fatty acids with 12-22 carbon atoms.


    [0044] They can be used in quantities of from 0,2 to 40 % weight and preferably from 1 to 20% by weight related to the starch.

    [0045] The starch blends can also contain polymeric compatibilizing agents having two components: one compatible or soluble with starch and a second one soluble or compatible with the polyester.

    [0046] Examples are starch/polyester copolymers through transesterification catalysts. Such polymers can be generated trough reactive blending during compounding or can be produced in a separate process and then added during extrusion. In general block copolymers of an hydrophilic and an hydrophobic units are particularly suitable. Additives such as di and polyepoxides, di and poly isocyanates, isocianurates, polycarbodiimmides and peroxides can also be added. They can work as stabilizers as well as chain extenders.

    [0047] All the products above can help to create the needed microstructure. It is also possible to promote in situ reactions to create bonds between starch and the polymeric matrix. Also aliphatic-aromatic polymers chain extended with aliphatic or aromatic diisocyanates or di and polyepoxides or isocianurates or with oxazolines with intrinsic viscosities higher than 1 dl/g or in any case aliphatic - aromatic polyesters with a ratio between Mn and MFI at 190°C, 2,16 kg higher than 10 000, preferably higher than 12 500 and more preferably higher than 15 000 can also be used to achieve the needed microstructure.

    [0048] Another method to improve the microstructure is to achieve starch complexation in the starch-polyester mixture.

    [0049] In this connection the content of EP 965 615 has to be intended as incorporated by reference in the present description. In such a case, in the X-Ray spectra of the compositions with the polyester according to the present invention , the Hc/Ha ratio between the height of the peak (HC) in the range of 13-14° of the complex and the height of the peak (Ha) of the amorphous starch which appears at about 20,5° (the profile of the peak in the amorphous phase having been reconstructed) is less than 2 and greater than 0,02.

    [0050] The starch polyester ratio is comprised in the range 5/95% weight up to 60/40% by weight, more preferably 10/90 - 45/55% by weight.

    [0051] In such starch-based blends in combination with the polyesters of the present invention it is possible to add polyolefines, polyvinyl alcohol at high and low hydrolysis degree, ethylene vinylalcohol and ethylene vinylacetate copolymers and their combinations as well as aliphatic polyesters such as polybuthylensuccinate, polybuthylensuccinate adipate, polybuthylensuccinate adipate-caprolactate, polybuthylensuccinate- lactate, polycaprolactone polymers and copolymers, PBT, PET, PTT, polyamides, polybuthylen terephthalate adipates with a content of terephthalic acid between 40 and 70% with and without solfonated groups with or without branchs and possibly chain extended with diisocyanates or isocyanurates, polyurethanes, polyamide-urethanes, cellulose and starch esters such as acetate, propionate and butyrate with substitution degrees between 1 and 3 and preferably between 1,5 and 2,5, polyhydroxyalkanoates, poly-L-lactic acid, poly-D-lactic acid and lactides, their mixtures and copolymers.

    [0052] The starch blends of the polyesters of the present invention maintain a better ability to crystallize in comparison with compostable starch blends where copolyester are polybutylenadipate terephthalates at terephthalic content between 45 and 49% (range of the product with industrial performances) and can be easily processable in film blowing even at MFI (170°C, 5kg) of 7 g/10 min due to the high crystallization rate of the matrix. Moreover they have impact strength higher than 20kj/m2, preferably higher than 30kj/m2 and most preferably higher than 45kj/m2 (measured on blown film 30 um thick at 10°C and less then 5% relative humidity).

    [0053] Particularly resistant and easily processable compounds contain destructurized starch in combination with the polyesters of the invention and polylactic acid polymers and copolymers with and without additives such as polyepoxydes, carbodiimmides and/or peroxides.

    [0054] The starch-base films can be even transparent in case of nanoparticles of starch with dimensions lower than 500 µm and preferably lower than 300 µm.

    [0055] It is also possible to go from a dispersion of starch in form of droplets to a dispersion in which two co-continuous phases coexist and the blend is characterized for allowing a higher water content during processing.

    [0056] In general, to obtain co-continuous structures it is possible to work either on the selection of starch with high amylopectine content and / or to add to the starch-polyester compositions block copolymers with hydrophobic and hydrophilic units. Possible examples are polyvinylacetate/polyvinylalcohol and polyester/polyether copolymers in which the block length, the balance between the hydrophilicity and hydrophobicity of the blocks and the quality of compatibilizer used can be suitably changed in order to finely adjust the microstructure of the starch-polyester compositions.

    [0057] The polyesters according to the invention can also be used in blends with the polymers of synthetic origin and polymers of natural origin mentioned above. Mixtures of polyesters with starch and polylactic acid are particularly preferred.

    [0058] Blends of the AAPE according the present invention with PLA are of particular interest because the high crystallization rate of the aliphatic-aromatic polyester of the invention and its high compatibility with PLA polymers and copolymers permits to cover materials with a wide range of rigidities and high speed of crystallization which makes these blends particularly suitable for injection molding and extrusion.

    [0059] Moreover, blends of such polyester with poly-L-lactic acid and poly-D-lactic acid or poly-L-lactide and D-lactide where the ratio between poly-L and poly-D-lactic acid or -lactide is in the range 10/90-90/10 and preferably 20/80-80/20 and the ratio between aliphatic- aromatic polyester and the polylactic acid or PLA blend is in the range 5-95- 95/5 and preferably 10/90-90/10 are of particular interest for the high crystallization speed and the high thermal resistance. Polylactic acid or lactide polymers or copolymers are generally of molecular weight Mn in the range between 30 000 and 300 000 and more preferably between 50 000 and 250 000.

    [0060] To improve the transparency and thoughness of such blends and decrease or avoid a lamellar structure of polylactide polymers it could be possible to introduce other polymers as compatibilizers or toughening agents such as polybuthylen succinate and copolymers with adipic acid and or lactic acid and or hydroxyl caproic acid, or polycaprolactone or aliphatic polymers of diols from C2 to C13 and diacids from C4 to C13 or polyhydroxyalkanoates or polyvinyl alcohol in the range of hydrolysis degree between 75 and 99% and its copolymers or polyvinylacetate in a range of hydrolysis degree between 0 and 70%, preferably
    between 0 and 60%. Particularly preferred as diols are ethylene glycol, propandiol, butandiol and as acids: azelaic, sebacic, undecandioic acid, dodecandioic acid and brassylic acid and their combinations.

    [0061] To maximize compatibility among the AAPE of the invention and poly lactic acid it is very useful the introduction of copolymers with blocks having high affinity for the aliphatic-aromatic copolyester of the invention and blocks with affinity for the poly lactic acid polymers or copolymers. Particularly preferred examples are block copolymers of the aliphatic aromatic copolymer of the invention with polylactic acid. Such block copolymers can be obtained taking the two original polymers terminated with hydroxyl groups and then reacting such polymers with chain extenders able to react with hydroxyl groups such as diisocyanates . Examples are 1,6 hexamethylendiisocyanate, isophorondiisocyanate, methylendiphenyldiisocyanate, toluendiisocyanate or the like. It is also possible to use chain extenders able to react with acid groups like di and poly epoxides (e.g. bisphenols diglycidyl ethers, glycerol diglycidyl ethers), divinyl derivatives if the polymers of the blend are terminated with acid groups.

    [0062] It is possible also to use as chain extenders carbodiimmides, bis-oxazolines, isocyanurates etc.

    [0063] The intrinsic viscosity of such block copolymers can be between 0,3 and 1,5dl/g, more preferred are between 0,45 and 1,2dl/g. The amount of compatibilizer in the blend of aliphatic aromatic copolyesters and polylactic acid can be in the range between 0,5 and 50%, more preferably between 1 and 30%, more preferably between 2 and 20% by weight.

    [0064] The AAPE according to the present invention can advantageously be blended also with filler both of organic and inorganic nature preferably. The preferred amount of fillers is in the range of 0.5 - 70 % by weight, preferably 5 - 50% by weight.

    [0065] As regards organic fillers wood powder, proteins, cellulose powder, grape residue, bran, maize husks, compost, other natural fibres, cereal grits with and without plasticizers such as polyols can be mentioned .

    [0066] As regards inorganic fillers, it can be mentioned substances able to be dispersed and/or to be reduced in lamellas with submicronic dimensions, preferably less than 500 nm, more preferably less than 300 nm, and even more preferably less than 50 nm. Particularly preferred are zeolites and silicates of various kind such as wollastonites, montmorillonites, hydrotalcites also functionalised with molecules able to interact with starch and or the specific polyester. The use of such fillers can improve stiffness, water and gas permeability, dimensional stability and maintain transparency.

    [0067] The process of production of the polyesters according to the present invention can be carried out according to any of the processes known to the state of the art. In particular the polyesters can be advantageously obtained with a polycondensation reaction.

    [0068] Advantageously, the process of polymerization of the copolyester can be conducted in the presence of a suitable catalyst. As suitable catalysts, there may be cited, by way of example, metallo-organic compounds of tin, for example derivatives of stannoic acid, titanium compounds, for example orthobutyl titanate, and aluminium compounds, for example triisopropyl aluminiums, antimony compounds, and zinc compounds.

    EXAMPLES



    [0069] In the examples provided hereinafter,
    • MFR was measured in the conditions envisaged by the ASTM D1238-89 standard at 150°C and 5 kg or at 190°C and 2.16 kg;
    • the melting and crystallization temperatures and enthalpies were measured with a differential scanning calorimeter Perkin Elmer DSC7, operating with the following thermo profile:

      1st scan from -30°C to 200°C at 20°C/min

      2nd scan from 200°C to -30°C at 10°C/min

      3rd scan from -30°C to 200°C at 20°C/min

    • tri was measured as endothermic-peak value of the 1st scan, and Tm2 as that of the 3rd scan; Tc was measured as exothermic-peak value of the 2nd scan.
    • Density


    [0070] Determination of Density according to the Mohr Westphal method has been performed with an analytical balance Sartorius AC 120S equipped with a Sartorius Kit YDK 01. The Kit is provided with two small baskets. Once the Kit has been mounted, ethanol has been introduced in the crystallizer. The balance has been maintained at room temperature.

    [0071] Each test has been performed with about 2 g of polymer (one or more pellets).

    [0072] The density d has been determined according to the above formula :

    Wa : weight of the sample in air

    Wf1 : weight of the sample in alcohol

    G = Wa - Wf1

    df1 = ethanol density at room temperature (Values read on tables provided by the company Sartorius with the Kit).



    [0073] The experimental error of the Density values is in the range of ± 2,5 x 10-3.
    • ηin has been determined according to the ASTM 2857-87 standard.
    • Mn has been determined on a Agilent 1100 Series GPC system with chloroform as eluent and polysterene standards for the calibration curve.

    Example 1



    [0074] A 25-1 steel reactor, provided with a mechanical stirrer, an inlet for the nitrogen flow, a condenser, and a connection to a vacuum pump was charged with:

    2865,4 g of dimethyl terephthalate (14.77 mol),

    3201.1 g of butandiol (35.57 mol),

    3072 g of brassylic acid (12.59 mol),

    7,0 g mono butylstannoic acid



    [0075] The molar percentage of aromatic content with respect to the sum of the acids was 54 mol%.

    [0076] The temperature of the reactor was then increased up to 200°C. After approximately 90% of the theoretical amount of water and methanol had been distilled, the pressure was gradually reduced to a value of less than 3 mmHg, and the temperature was raised to 240°C.

    [0077] After approximately 4 hours, a product was obtained with inherent viscosity (measured in chloroform at 25°C, c = 0.2 g/dl) ηin = 1.09 (dl/g), density 1.15 g/cc, Mn = 80100, Mw/Mn = 2.3 and MFR (190°C; 2.16 kg) = 3.1 g/10 min.

    Example 2



    [0078] The process of Example 1 was repeated with :

    3244 g of dimethyl terephthalate (16.72 mol),

    3260.7 g of butandiol (36.23 mol),

    2720.1 g of brassylic acid (11.15 mol)

    7,0 g mono butylstannoic acid



    [0079] The molar percentage of aromatic content with respect to the sum of the acids was 60 mol%.

    [0080] After approximately 4 hours, a product was obtained with inherent viscosity (measured in chloroform at 25°C, c = 0.2 g/dl) ηin = 0.91 (dl/g), density 1.16 g/cc, Mn = 70720, Mw / Mn = 2.3 and MFR (190°C; 2.16 kg) = 4.4 g/10 min.he specimens of the examples were then filmed with the blow-film technique, on Formac Polyfilm 20, equipped with metering screw 20C13, L/D = 25, RC = 1.3; air gap 1 mm; 30-50 RPM; T = 140- 180 °C. The blow up ratio was 2.5 whereas the draw down ratio was 10. The films thus obtained had a thickness of approximately 30 µ.

    [0081] A week after filming, and after conditioning at 25°C, with 55% relative humidity, the tensile properties were measured according to the ASTM D882-88 standards.

    [0082] Appearing in Table 1 are the thermal properties of the materials of the examples, whilst Table 2 gives the mechanical properties of the films.
    TABLE 1
    Thermal properties
    ExampleAromatic ContentTm1 (°C)ΔHm1 (J/q)Tc (°C)ΔHc (J/qTm2 (°C)
    1 54% - - 76 16 133
    2 60% - - 85 20 144
    TABLE 2
    Mechanical properties
    EXAMPLE12
    Tensile properties    
    - longitudinal    
    Yield point (MPa) 7 8.5
    Ultimate strength 38.5 35
    (MPa)    
    Elastic modulus 70 100
    (MPa)    
    Energy at 123 150
    break (MJ/m3)    
    Elmendorf tear    
    strength (N/mm)    
    (A) Longitudinal 24 24
    direction    
    B) Cross direction 156 113
    (A+B)/2 90 68.5

    Disintegration TEST



    [0083] For the materials of Example 1 and 2 the disintegration test was conducted in simulated composting conditions in a laboratory-scale test according to the Standard ISO 20200 .

    [0084] The tests were conducted on < 150-200 micron compression molded films ground in liquid nitrogen until they were fragmented to sizes of less than 2 mm. After 90 days the material samples were completely disintegrated according to the Standard.
    TABLE 3 DISINTEGRATION
    ExampleAromatic contentDiacid/ DiolDisintegration After 90 days
    1 54% Brassylic Butandiol complete
    2 60% Brassylic Butandiol complete
    TABLE 4 DENSITY
    ExampleAromatic contentDiacid/ DiolDensity
    1 54% Brassylic 1.15
        Butandiol  
    2 60% Brassylic 1.16
        Butandiol  



    Claims

    1. Biodegradable aliphatic/aromatic copolyester (AAPE) comprising:

    A) an acid component comprising repeating units of:

    1) 49 to 63 mol % of a polyfunctional aromatic acid;

    2) 51 to 37 % of an aliphatic acid, at least 50% of which is brassylic acid;

    B) a diol component;
    said AAPE being disintegrated according to the Standard ISO 20200 in 90 days days, and having:

    - a density of less than or equal to 1.18 g/cc;

    - a number average molecular weight Mn of 40,000-140,000;

    - an inherent viscosity of 0.8 - 1.5.


     
    2. Biodegradable polyesters according to Claim 1, characterized in that said acid component A) comprises repeating units of:

    1) 50 to 60 mol % of a polyfunctional aromatic-acid;

    2) 50 to 40 mol % of an aliphatic acid, at least 50% of which is brassylic acid.


     
    3. Biodegradable polyesters according to claim 1 or 2, characterized by a density of less than 1.17 g/cc.
     
    4. Biodegradable polyesters according to Claim 1 or 2, characterized in that said polyfunctional aromatic acid is a dicarboxylic acid.
     
    5. Biodegradable polyester according to claim 1, characterized by having a crystallization temperature Tc higher than 35°C.
     
    6. Biodegradable polyester according to claim 1, characterized by having a crystallization temperature Tc higher than 40°C.
     
    7. Biodegradable polyester according to claim 1, characterized by having a crystallization temperature Tc higher than 50°C.
     
    8. Biodegradable polyester according to claim 1, characterized by having a Energy at break higher than 100 Mj/m2.
     
    9. Biodegradable polyester according to claim 8, characterized by having a Elmendorf tear strength higher than 100 N/mm in the cross direction, higher than 20 N/mm in the longitudinal direction and higher than 60 N/mm for the quantity (cross direction + longitudinal direction) / 2.
     
    10. Biodegradable polyester according to any of the preceding claims, in which the dialcohols are selected from the group • consisting of 1,2-ethandiol, 1,2-propandiol, 1,3-propandiol, 1,4-butandiol, 1,5-pentandiol, 1,6-hexandiol, 1,7-heptandiol, 1,8-octandiol, 1,9-nonandiol, 1,10-decandiol, 1,11-undecandiol, 1,12-dodecandiol, 1,13-tridecandiol, 1,4-cyclohexandimethanol, propylene glycol, neo-pentyl glycol, 2-methyl-1,3-propandiol, dianhydrosorbitol, dianhydromanntol, dianhydroiditol, cyclohexandiol, and cyclohexan-mechandiol.
     
    11. Biodegradable polyester according to claim 10, characterized in that said dialcohols are diols of the C2 - C10 type.
     
    12. Biodegradable polyester according to claim 10, characterized in that said dialcohols are C2 - C4 diols.
     
    13. Biodegradable polyester according tc claim 10, characterized in that said dialcohols is 1-4 butandiol.
     
    14. Biodegradable polyester according to claim 4, characterized in that said dicarboxylic acid is selected from the group consisting of the phthalic acids.
     
    15. Biodegradable polyester according to claim 4, characterized in that said dicarboxylic acid is terephthalic acid.
     
    16. Blend comprising a biodegradable polyester according to any of the receding claims, obtained by reactive extrusion both with polyesters of the same type and with other biodegradable polymers whether of natural origin or of synthetic origin.
     
    17. Blend of biodegradable polyesters according to Claim 16, characterized in that the polymers of synthetic origin are selected from the group consisting of polylactic acid, poly-ε-caprolactone, polyhydroxybutyrates, such as polyhydroxybutyrate-valerate, holyhydroxybutyrate propanoate, polyhydroxybutyrate-hexanoate, polyhydroxybutyrate-decanoate, polyhydroxybutyrate-dodecanoate, polyhydroxybutyrate-hexadecanoate, polyhydroxybutyrate-octadecanoate, and polyalkylene succinates.
     
    18. Blend of biodegradable polyesters according to Claim 16, wherein the polymers of natural origin are starch, cellulose, chitosan, alginates or natural rubbers.
     
    19. Blend of biodegradable polyesters according to Claim 18, wherein said starches and celluloses are modified.
     
    20. Blend according to claim 18, wherein said starch or cellulose are esters with a degree of substitution of between 0.2 and 2.5, hydroxypropylated starches, and modified starches with fatty chains.
     
    21. Blend of biodegradable polyesters according to Claim 18, in which the starch is present in the destructured or gelatinized form or in the form of fillers.
     
    22. The blends of biodegradable polyesters according to Claim 16 in which the polymer of synthetic origin is polylactrac acid and the polymer of natural origin is starch.
     
    23. Use of the polyesters according to one of the preceding claims for the production of :

    - films, whether one-directional or two-directional films, and multilayer films with other polymeric materials;

    - films for use in the agricultural sector as mulching films;

    - bags and sheathes for gathering organic matter;

    - packaging for foodstuffs both single-layer and multilayer, such as for example containers for milk, yoghurt, meat, beverages;

    - coatings obtained with the extrusion-coating technique;

    - multilayer laminate with layers of paper, plastic materials, aluminium, metallized films;

    - foamed or foamable beads for the production of pieces formed by wintering;

    - foamed and semi-foamed products including foamed blocks made up of pre-foamed particles;

    - foamed sheets, thermoformed sheets and containers obtained therefrom for the packaging of foodstuffs;

    - containers in general for fruit and vegetables;

    - composites with gelatinized, destructured and/or complexes starch, natural starch, flours, other fillers of natural, vegetal or inorganic origin;

    - fibres, fabrics and non-woven fabrics for the sector of health, sanitary products, and hygiene.


     


    Ansprüche

    1. Biologisch abbaubarer aliphatisch/aromatischer Copolyester (AAPE), der folgendes umfasst:

    A) eine Säurekomponente, die folgende Wiederholungseinheiten umfasst:

    1) 49 bis 63 mol% einer polyfunktionellen aromatischen Säure;

    2) 51 bis 37 mol% einer aliphatischen Säure, von der mindestens 50 % Brassylsäure sind;

    B) eine Diolkomponente;
    wobei AAPE gemäß dem Standard ISO 20200 in 90 Tagen abgebaut wird und folgendes aufweist:

    - eine Dichte von weniger oder gleich 1,18 g/cc;

    - ein zahlengemitteltes Molekulargewicht Mn von 40.000 bis 140.000;

    - eine inhärente Viskosität von 0,8 bis 1,5.


     
    2. Biologisch abbaubare Polyester gemäß Anspruch 1, die dadurch gekennzeichnet sind, dass die Säurekomponente A) folgende Wiederholungseinheiten umfasst:

    1) 50 bis 60 mol% einer polyfunktionellen aromatischen Säure;

    2) 50 bis 40 mol% einer aliphatischen Säure, von der mindestens 50 % Brassylsäure sind.


     
    3. Biologisch abbaubare Polyester gemäß Anspruch 1 oder 2, die durch eine Dichte von weniger als 1,17 g/cc gekennzeichnet sind.
     
    4. Biologisch abbaubare Polyester gemäß Anspruch 1 oder 2, wobei die polyfunktionelle aromatische Säure eine Dicarbonsäure ist.
     
    5. Biologisch abbaubarer Polyester gemäß Anspruch 1, der durch eine Kristallisationstemperatur Tc von mehr als 35°C gekennzeichnet ist.
     
    6. Biologisch abbaubarer Polyester gemäß Anspruch 1, der durch eine Kristallisationstemperatur Tc von mehr als 40°C gekennzeichnet ist.
     
    7. Biologisch abbaubarer Polyester gemäß Anspruch 1, der durch eine Kristallisationstemperatur Tc von mehr als 50°C gekennzeichnet ist.
     
    8. Biologisch abbaubarer Polyester gemäß Anspruch 1, der durch eine Bruchenergie von mehr als 100 MJ/m2 gekennzeichnet ist.
     
    9. Biologisch abbaubarer Polyester gemäß Anspruch 8, der dadurch gekennzeichnet ist, dass er eine Elmendorf-Reißfestigkeit von mehr als 100 N/mm in der Querrichtung, von mehr als 20 N/mm in der Längsrichtung und mehr als 60 N/mm für das Maß (Querrichtung + Längsrichtung)/2 aufweist.
     
    10. Biologisch abbaubarer Polyester gemäß irgendeinem der vorangehenden Ansprüche, bei dem die Dialkohole ausgewählt sind aus 1,2-Ethandiol, 1,2-Propandiol, 1,3-Propandiol, 1,4-Butandiol, 1,5-Pentandiol, 1,6-Hexandiol, 1,7-Heptandiol, 1,8-Octandiol, 1,9-Nonandiol, 1,10-Decandiol, 1,11-Undecandiol, 1,12-Dodecandiol, 1,13-Tridecandiol, 1,4-Cyclohexandimethanol, Propylenglycol, Neopentylglycol, 2-Methyl-1,3-propandiol, Sorbitoldianhydrid, Mannitoldianhydrid, Iditoldianhydrid, Cyclohexandiol und Cyclohexanmethandiol.
     
    11. Biologisch abbaubarer Polyester gemäß Anspruch 10, dadurch gekennzeichnet, dass die Dialkohole Diole vom C2-C10-Typ sind.
     
    12. Biologisch abbaubarer Polyester gemäß Anspruch 10, dadurch gekennzeichnet, dass die Dialkohole C2-C4-Diole sind.
     
    13. Biologisch abbaubarer Polyester gemäß Anspruch 10, dadurch gekennzeichnet, dass der Dialkohol 1,4-Butandiol ist.
     
    14. Biologisch abbaubarer Polyester gemäß Anspruch 4, dadurch gekennzeichnet, dass die Dicarbonsäure aus der Gruppe, bestehend aus Phthalsäuren, ausgewählt ist.
     
    15. Biologisch abbaubarer Polyester gemäß Anspruch 4, dadurch gekennzeichnet, dass die Dicarbonsäure Terephthalsäure ist.
     
    16. Mischung, die einen biologisch abbaubaren Polyester gemäß irgendeinem der vorangehenden Ansprüche umfasst, die durch Reaktionsextrusion von sowohl Polyestern des gleichen Typs als auch mit anderen biologisch abbaubaren Polymeren, ob natürlicher Herkunft oder synthetischer Herkunft, erhältlich ist.
     
    17. Mischung von biologisch abbaubaren Polyestern gemäß Anspruch 16, dadurch gekennzeichnet, dass die Polymere synthetischer Herkunft aus der Gruppe ausgewählt sind, die aus Polymilchsäure, Poly-ε-caprolakton, Polyhydroxybutyraten, wie Polyhydroxybutyratvalerat, Polyhydroxybutyratpropanoat, Polyhydroxybutyrathexanoat, Poloyhydroxybutyratdecanoat, Polyhydroxybutyratdodecanoat, Polyhydroxybutyrathexadecanoat, Polyhydroxybutyratoctadecanoat und Polyalkylensuccinaten besteht.
     
    18. Mischung biologisch abbaubarer Polyester gemäß Anspruch 16, wobei die Polymere natürlicher Herkunft Stärke, Cellulose, Chitosan, Alginaten oder natürliche Kautschuke sind.
     
    19. Mischung biologisch abbaubarer Polyester gemäß Anspruch 18, wobei die Stärken und Cellulosen modifiziert sind.
     
    20. Mischung gemäß Anspruch 18, wobei die Stärke oder Cellulose Ester mit einem Substitutionsgrad zwischen 0,2 und 2,5, hydroxypropylierte Stärken und Fettkettenmodifizierte Stärken sind.
     
    21. Mischung biologisch abbaubarer Polyester gemäß Anspruch 18, bei der die Stärke in destrukturierter oder Gelatineform oder in Form von Füllern vorliegt.
     
    22. Mischung biologisch abbaubarer Polyester gemäß Anspruch 16, bei der das Polymer synthetischer Herkunft Polymilchsäure ist und das Polymer natürlicher Herkunft Stärke ist.
     
    23. Verwendung der Polyester gemäß einem der vorangehenden Ansprüche für die Herstellung von:

    - Filmen, ob ein-direktionale oder zwei-direktionale Filme, und Mehrschichtfilmen mit anderen polymeren Materialien;

    - Filmen zur Verwendung im landwirtschaftlichen Bereich als Mulchfilme;

    - Taschen und Behältnissen zum Sammeln von organischem Material;

    - Lebensmittelverpackungen, sowohl ein-schichtig als auch mehr-schichtig, wie z.B. Behälter für Milch, Joghurt, Fleisch, Getränke;

    - Beschichtungen, erhältlich durch die Extrusions-Beschichtungstechnik;

    - Mehrschichtlaminaten mit Schichten aus Papier, Plastikmaterialien, Aluminium, metallierten Filmen;

    - geschäumten oder schäumbaren Kugeln zur Herstellung von Sinter-geformten Stücken;

    - geschäumten und halb-geschäumten Produkten einschließlich geschäumter Blöcke, hergestellt aus vorgeschäumten Partikeln;

    - geschäumten Blättern, wärmegeformten Blättern und Behältern die daraus erhalten werden, zum Verpacken von Lebensmitteln;

    - Behältern, im allgemeinen für Obst und Gemüse;

    - Gemischen mit gelatinierter und destrukturierter und/oder komplexer Stärke, natürlicher Stärke, Mehlen, anderen natürlichen Füllern pflanzlicher oder anorganischer Herkunft;
    Fasern, Stoffen und Faservliesen für den Gesundheitsbereich, Sanitärprodukte und Hygiene.


     


    Revendications

    1. Copolyester aliphatique/aromatique biodégradable (AAPE) comprenant :

    A) un composant acide comprenant des unités répétitives de :

    1) 49 % à 63 % en mole d'un acide aromatique polyfonctionnel ;

    2) 51 % à 37 % d'un acide aliphatique, dont au moins 50 % est l'acide brassylique ;

    B) un composant diol ;
    ledit AAPE étant désintégré selon la norme ISO 20200 en 90 jours, et ayant :

    - une masse volumique inférieure ou égale à 1,18 g/cm3 ;

    - un poids moléculaire moyen en nombre Mn de 40 000 à 140 000 ;

    - une viscosité intrinsèque de 0,8 à 1,5.


     
    2. Polyesters biodégradables selon la revendication 1, caractérisés en ce que ledit composant acide A) comprend des unités répétitives de :

    1) 50 % à 60 % en mole d'un acide aromatique polyfonctionnel ;

    2) 50 % à 40 % en mole d'un acide aliphatique, dont au moins 50 % et l'acide brassylique.


     
    3. Polyesters biodégradables selon la revendication 1 ou 2, caractérisés par une masse volumique inférieure à 1,17 g/cm3.
     
    4. Polyesters biodégradables selon la revendication 1 ou 2, caractérisés en ce que ledit acide aromatique polyfonctionnel est un acide diacide carboxylique.
     
    5. Polyester biodégradable selon la revendication 1, caractérisé en ce qu'il possède une température de cristallisation Tc supérieure à 35° C.
     
    6. Polyester biodégradable selon la revendication 1, caractérisé en ce qu'il possède une température de cristallisation Tc supérieure à 40° C.
     
    7. Polyester biodégradable selon la revendication 1, caractérisé en ce qu'il possède une température de cristallisation Tc supérieure à 50° C.
     
    8. Polyester biodégradable selon la revendication 1, caractérisé en ce qu'il possède une énergie à la rupture supérieure à 100 MJ/m2.
     
    9. Polyester biodégradable selon la revendication 8, caractérisé en ce qu'il possède une résistance à la déchirure d'Elmendorf supérieure à 100 N/mm dans la direction transversale, supérieur à 20 N/mm dans la direction longitudinale et supérieure à 60 N/mm pour la quantité (direction transversale + direction longitudinale)/2.
     
    10. Polyester biodégradable selon l'une quelconque des revendications précédentes, dans lequel les dialcools sont choisis parmi le groupe consistant 1,2-éthandiol, 1,2-propandiol, 1,3-propandiol, 1,4-butandiol, 1,5-pentandiol, 1,6-hexandiol, 1,7-heptandiol, 1,8-octandiol, 1,9-nonandiol, 1,10-décandiol, 1,11-undécandiol, 1,12-dodécandiol, 1,13-tridécandiol, 1,4-cyclohexandiméthanol, propylène glycol, néo-pentyl glycol, 2-méthyl-1,3-propandiol, dianhydrosorbitol, dianhydromannitol, dianhydroiditol, cyclohexandiol, et cyclohexan-méthandiol.
     
    11. Polyester biodégradable selon la revendication 10, caractérisé en ce que lesdits dialcools sont des diols du type C2 - C10.
     
    12. Polyester biodégradable selon la revendication 10, caractérisé en ce que lesdits dialcools sont des diols en C2-C4.
     
    13. Polyester biodégradable selon la revendication 10, caractérisé en ce que ledit dialcool est le 1,4-butandiol.
     
    14. Polyester biodégradable selon la revendication 4, caractérisé en ce que ledit diacide carboxylique est choisi parmi le groupe constitué des acides phtaliques.
     
    15. Polyester biodégradable selon la revendication 4, caractérisé en ce que ledit diacide carboxylique est l'acide téréphtalique.
     
    16. Mélange comprenant un polyester biodégradable selon l'une quelconque des revendications précédentes, obtenu par extrusion réactive à la fois avec des polyesters du même type et avec d'autres polymères biodégradables qu'ils soient d'origine naturelle ou d'origine synthétique.
     
    17. Mélange de polyesters biodégradables selon la revendication 16, caractérisé en ce que les polymères d'origine synthétique sont choisis parmi le groupe consistant en acide polylactique, poly-ε-caprolactone, polyhydroxybutyrates, tels que le polyhydroxybutyrate-valérate, le polyhydroxybutyrate le propanoate, le polyhydroxybutyrate-hexanoate, le polyhydroxybutyrate-décanoate, le polyhydroxybutyrate-dodécanoate, le polyhydroxybutyrate-hexadécanoate, le polyhydroxybutyrate-octadécanoate, et des polyalkylène succinates.
     
    18. Mélange de polyesters biodégradables selon la revendication 16, caractérisé en ce que les polymères d'origine naturelle sont l'amidon, la cellulose, le chitosan, des alginates ou des caoutchoucs naturels.
     
    19. Mélange de polyesters biodégradables selon la revendication 18, où lesdits amidons et celluloses sont modifiés.
     
    20. Mélange selon la revendication 18, où ledit amidon ou ladite cellulose sont des esters avec un degré de substitution compris entre 0,2 et 2,5, des amidons hydroxypropylés, et des amidons modifiés avec des chaînes grasses.
     
    21. Mélange de polyesters biodégradables selon la revendication 18, dans lequel l'amidon est présent sous la forme déstructurée ou gélatinisée ou sous la forme de charges.
     
    22. Mélanges de polyesters biodégradables selon la revendication 16, dans lesquels le polymère d'origine synthétique est un acide polylactique et le polymère d'origine naturelle est l'amidon.
     
    23. Utilisation des polyesters selon l'une des revendications précédentes pour la production de :

    - films, que ce soit des films monodirectionnels ou bidirectionnels, et films multicouches avec d'autres matériaux polymères ;

    - films destinés à une utilisation dans le secteur agricole en tant que films de paillage;

    - -sacs et gaines pour le ramassage de la matière organique ;

    - -emballage de produits alimentaires à la fois monocouche et multicouche, tel que par exemple des conteneurs pour le lait, les yaourts, la viande, les boissons ;

    - revêtements obtenus avec la technique de revêtement par extrusion ;

    - -stratifiés multicouches avec des couches de papier, matières plastiques, aluminium, et films métallisés ;

    - -billes expansées ou expansibles pour la production de pièces formées par frittage ;

    - -produits expansés ou semi-expansés comprenant des blocs expansés fait de particules pré-expansées ;

    - -feuilles expansées, feuilles thermoformés et conteneurs obtenus à partir de ces dernières pour l'emballage de produits alimentaires ;

    - -conteneurs de manière générale pour des fruits et des légumes ;

    - -composites d'amidon gélifié, déstructuré et/ou complexé, amidon naturel, farines, autre charge d'origine naturelle, végétale ou inorganique ;

    - -fibres, tissus et tissus non-tissés pour le secteur de la santé, des produits sanitaires, et de l'hygiène.


     






    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description




    Non-patent literature cited in the description