(19)
(11)EP 2 941 444 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
29.04.2020 Bulletin 2020/18

(21)Application number: 13818215.9

(22)Date of filing:  19.12.2013
(51)International Patent Classification (IPC): 
C08F 20/18(2006.01)
C08F 2/38(2006.01)
C08F 10/14(2006.01)
C08L 23/24(2006.01)
C08F 20/68(2006.01)
C10M 145/14(2006.01)
C10M 107/10(2006.01)
C08L 33/06(2006.01)
(86)International application number:
PCT/EP2013/077323
(87)International publication number:
WO 2014/106587 (10.07.2014 Gazette  2014/28)

(54)

PREPARATION OF LOW-VISCOSITY POLYMERS

HERSTELLUNG VON POLYMEREN MIT GERINGER VISKOSITÄT

PRÉPARATION DE POLYMÈRES À FAIBLE VISCOSITÉ


(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: 04.01.2013 US 201361749091 P
29.01.2013 EP 13152972

(43)Date of publication of application:
11.11.2015 Bulletin 2015/46

(73)Proprietor: Evonik Operations GmbH
45128 Essen (DE)

(72)Inventors:
  • SIRAK, Sofia M.
    60598 Frankfurt (DE)
  • RADANO, Christopher Paul
    West Chester, Pennsylvania 19382 (US)

(74)Representative: Evonik Patent Association 
c/o Evonik Industries AG IP Management PB 84/339 Rodenbacher Chaussee 4
63457 Hanau
63457 Hanau (DE)


(56)References cited: : 
WO-A1-01/40333
WO-A1-2010/043503
DE-A1- 10 314 776
WO-A1-2008/058774
WO-A1-2012/076676
US-A- 6 066 603
  
      
    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 method for the preparation of low-viscosity polymers suitable as base fluids for lubricants based on a mixture of polar and non-polar building blocks. The method comprises polymerizing a reaction mixture of 1-alkenes and ethylenically unsaturated monomers in the presence of a cobalt catalytic chain transfer agent.

    [0002] The present invention relates to the field of lubrication. Lubricants typically contain a base fluid and variable amounts of additives. A good lubricant should possess a high boiling and low freezing point, a high viscosity index, good thermal stability, low susceptibility to corrosion, and a high resistance to oxidation. These properties are significantly determined by the additives used. Therefore, a base fluid that can support a broad variety of additives is needed to improve the overall performance of the lubricant.

    [0003] According to the American Petroleum Institute (API) lubricant base fluids are subdivided into different groups. Groups I to III encompass different mineral oils distinguished by their degree of saturation, sulphur content, and viscosity index. Group IV encompasses polyalphaolefins. Group V encompasses all other base fluids including napthenics, polyalkylene glycol oils, and esters. Base fluids for lubricants may especially be oils having a kinematic viscosity in the range of 3 to 100 mm2/s, preferably 13 to 65 mm2/s measured at 40°C according to ASTM D 445.

    [0004] The term mineral oil commonly refers to oils derived from crude oil fractions. Mineral oils of groups I to III are therefore regarded as native oils. In contrast, base fluids of groups IV and V are regarded as synthetic base fluids.

    [0005] Synthetic base fluids are growing in interest and are preferred over mineral oils due to their greater oxidative and chemical stability, improved viscosity index and reduced pour point. Further, their properties may be systematically controlled during synthesis to optimize the structure-property profile of the base fluids. Due to their synthesis from relatively pure raw material, synthetic base fluids also contain fewer unwanted by-products with deleterious effects.

    [0006] Polyalphaolefins (PAOs) are polymers of 1-alkenes (alpha olefins), for example 1-decene. PAOs have a flexible alkyl side chain on every other carbon atom of the polymer backbone. Due to the large number and high conformational variability of the alkyl side chains, PAOs do not crystallize or solidify easily and remain viscous liquids even at low temperatures. Further, PAOs offer a high oxidative and chemical stability, and can be produced by well-developed synthetic processes. Therefore, PAOs find widespread use in engine oil, transmission oil, industrial gear oil, and hydraulic oil applications. However, PAOs are inherently non-polar and are therefore incompatible with polar additives, such as viscosity modifiers.

    [0007] Ester oils are group V base fluids that may have superior solubility, additive compatibility and viscosimetrics compared to PAOs. However, ester oils are susceptible to hydrolysis, leading to a fluid with greater potential to induce corrosion.

    [0008] Polymers based on a mixture of polar and non-polar buildings blocks, such as methacrylate and alpha olefins, potentially combine the benefits of PAOs and ester oils. The methacrylate component may provide polarity to the polymer, while the alpha olefin component may help maintaining the miscibility with common mineral oil and non-polar synthetic oils.

    [0009] Gosh et al. have demonstrated the synthesis of high molecular weight polymers from iso-decyl methacrylate and 1-decene (P. Gosh et al., Indian Journal of Chemical Technology, 1998, vol. 5, pp. 371-375). These polymers incorporated up to 13% of 1-decene into the backbone using standard free radical initiators (e.g. AIBN) and solvent. The polymers were shown to be suitable as viscosity modifiers when used at low concentrations as additives for engine oils. However, because these polymers are of high molecular weight and high viscosity, they are susceptible to significant viscosity loss upon mechanical shearing. Thus, their high viscosity precludes their use as base fluids to dissolve other viscosity modifiers. Further, due to the low concentrations these polymers are used at, they do not offer the ability to adjust the fluid polarity in formulations.

    [0010] US 5,691,284 discloses the synthesis of polymers from (meth)acrylic acid esters and alpha olefins. However, the method disclosed in US 5,691,284 does not yield polymers with a kinematic viscosity lower than 25 mm2/s at 100°C according to ASTM D 445. In light of the fact that low viscosity base fluids are needed as engine oils to achieve a high fuel efficiency in combustion engines, an even lower viscosity is desired. Further, the synthesis of the low viscosity polymers disclosed in US 5,691,284 requires at least 4% of free radical initiator. This high amount of free radical initiator results in a high concentration of potentially corrosive by-products. Another detriment is the large amount of alpha olefins required to achieve a low viscosity. Such large incorporation of alpha olefin offsets the benefit of achieving a fluid whose polarity can be tuned through the incorporation of different (meth)acrylic acid esters. Finally, because of the different reactivity of (meth)acrylic acid esters and alpha olefins, long reaction times are required. This results in an impractical process for generating base fluids within standard manufacturing processes.

    [0011] Catalytic chain transfer (CCT) is a process which involves adding a catalytic chain transfer agent to a radical polymerization reaction to achieve greater control over the length of the resulting polymers. It is known that cobalt porphyrins can be used as catalytic chain transfer agents in the polymerization of methylmethacrylate to reduce the molecular weight of the resulting poly-methylmethacrylate (N. S. Enikolopyan et al., Journal of Polymer Science: Polymer Chemistry Edition, 1981, vol. 19, pp. 879-889).

    [0012] US 2009/0012231 A1 discloses macromonomers synthesized by cobalt-catalyzed chain transfer free radical polymerizations of (meth)acrylic monomers. It further discloses the preparation of a pigment dispersion from the reaction of said macromonomers with monomeric or oligomeric amines. However, US 2009/0012231 A1 does not relate to the synthesis of low-viscosity polymers.

    [0013] US 4,680,352 discloses the use of different Co(II) chelates as catalytic chain transfer agents for controlling the molecular weight of homopolymers and copolymers produced in free radical polymerization processes. In particular, US 4,680,352 relates to the polymerization of (meth)acrylic acid ester monomers and styrene monomers.

    [0014] In order to reduce the kinematic viscosity of a lubricating oil composition, a standard method well-known in the art consists in making a dilution of the viscosity improver in a base oil.
    DE 10314776A1 relates to a lubricating oil composition having a lubricating oil and at least one additive having friction-reducing properties. The viscosity improver is prepared by ATRP polymerization of monomer compositions, wherein the catalyst comprises at least one transition metal, so that the transition metal compound can form a redox cycle with the initiator or the polymer chain which has a transferable atom group. As stated in DE 10314776A1, in these cycles, the transferable atom group and the catalyst reversibly form a bond, and the oxidation state of the transition metal is increased or lowered. Cobalt is cited as a possible transition metal. The different VI improvers prepared according to the process disclosed in DE 10314776A1 are dissolved in a paraffinic base oil in order to lower/adjust their kinematic viscosity.
    A similar polymerization process based on an ATRP polymerization (Transition metal-mediated living radical polymerization) is also described in WO 01/40333A1. Gradient copolymers are prepared by a ATRP method, wherein the monomers are polymerized by means of initiators by the formula Y-(X)m, wherein Y represents the case molecule, of which it is assumed that it forms radicals, X represents a transferable atom. It is indicated that the addition of a transition metal compound in presence of a ligand to the transferable atomic group facilitates the polymerization process, resulting in polymers having a narrow molecular weight distribution. Cobalt is mentioned as a possible transition metal, although the transition metal usually used is copper. The resulting polymers are then diluted with a group I or group II mineral oil to lower their kinematic viscosity. WO 2010/043503 discloses a method for reducing noise in a hydraulic system by contacting a hydraulic fluid comprising a polyalkyl(meth)acrylate polymer. As indicated in WO 2010/043503, in order to achieve a prescribed ISO viscosity grade, a base stock having a low viscosity grade is mixed with the poylalkyl(meth)acrylate polymer, said base stock being a mineral oil and/or a synthetic oil.
    WO 2012/076676A1 relates to a VI improver comprising a polyalkyl(meth)acrylate polymer, wherein the viscosimetric determined values of the different VI improver is made after dilution in a Group III mineral oil.
    WO 2008/058774 relates to method for controlling the quality of a functional fluid, wherein a metal compound is added as a marker to the functional fluid to detect the functional fluid in a mixture. As indicated in WO 2008/058774, the metal compound, which can be Cobalt, should have no detrimental effect to the functional fluid or to the equipment hardware in which the functional fluid is used.

    [0015] The present invention aims at providing an improved method for the preparation of low viscosity polymers from ethylenically unsaturated monomers, preferably (meth)acrylic acid esters. The polymers prepared should preferably have a kinematic viscosity of less than 25 mm2/s measured at 100°C according to ASTM D 445. Further, the method should require low amounts of free radical initiator and should allow to tailor the polarity of the polymers through (meth)acrylate side chain functionality. Additionally, the polymers should have superior viscosity indices and comparable volatilities when compared to state of the art base fluids. The present invention also aims at providing a method for preparing said polymers under short reaction times and with minimal by-products.

    [0016] In the context of the present invention, the term "(meth)acrylic" refers to either acrylic or to methacrylic, or mixtures of acrylic and methacrylic. Correspondingly, the term "(meth)acrylate" refers to either acrylate or to methacrylate, or mixtures of acrylate and methacrylate.

    [0017] In a first aspect, the present invention relates to a method for preparing a polymer composition having a kinematic viscosity of less than 25 mm2/s measured at 100°C according to ASTM D 445. This method comprises the steps of:
    1. a) preparing a reaction mixture comprising
      as component A) an ethylenically unsaturated monomer or a mixture of ethylenically unsaturated monomers and
      as component B) a 1-alkene or a mixture of 1-alkenes;
    2. b) adding a Co(II) complex as a catalytic chain transfer agent to the reaction mixture;
    3. c) adding a radical initiator; and
    4. d) reacting the reaction mixture to obtain the polymer composition,
      wherein the total amount of the radical initiator added to the reaction mixture is at least 0.05% by weight relative to the total weight of components A) and B);
      wherein the component A) is a compound of formula (I) or a mixture of compounds of formula (I)

      wherein R1 and R2 independently represent a hydrogen atom or a group of the formula -COOR5, R3 represents a hydrogen atom or a methyl group, R4 represents a C1 to C30 alkyl group, a C2 to C30 alkenyl group, a C2 to C30 alkinyl group or a C3 to C30 cycloalkyl group, and R5 represents a hydrogen atom or a C1 to C30 alkyl group, a C2 to C30 alkenyl group, or a C2 to C30 alkinyl group, and
      wherein the reaction mixture prepared in step a) comprises at least 50% by weight of component A) relative to the total weight of components A) and B).


    [0018] Optionally, the method further comprises after step d) an additional step of distilling off the residual 1-alkene.

    [0019] The method is based on a catalytic chain transfer (CCT) process, which means that it involves adding a catalytic chain transfer agent to a radical polymerization reaction.

    [0020] It has been found that with the inventive method, polymers of a kinematic viscosity of less than 25 mm2/s, preferably less than 20 mm2/s, more preferably less than 15 mm2/s measured at 100°C according to ASTM D 445 can be prepared.

    [0021] The reaction mixture prepared in step a) comprises at least 50% by weight of component A) relative to the total weight of components A) and B). The reaction mixture prepared in step a) preferably comprises at least 10% by weight of component B) relative to the total weight of components A) and B). Most preferably the reaction mixture prepared in step a) comprises 50 to 90% by weight of component A) and 10 to 50% by weight of component B) relative to the total weight of components A) and B).

    [0022] According to the present invention, component A) consists of a compound according to formula (I) or a mixture of compounds according to formula (I)

    wherein R1 and R2 independently represent a hydrogen atom or a group of the formula -COOR5, R3 represents a hydrogen atom or a methyl group, R4 represents a C1 to C30 alkyl group, a C2 to C30 alkenyl group, a C2 to C30 alkinyl group or a C3 to C30 cycloalkyl group, and R5 represents a hydrogen atom or a C1 to C30 alkyl group, a C2 to C30 alkenyl group, or a C2 to C30 alkinyl group.

    [0023] In a preferred embodiment, R1 and R2 represent hydrogen atoms, R3 represents a hydrogen atom or a methyl group, and R4 represents a C1 to C30 alkyl group, preferably a C6 to C15 alkyl group, even more preferably a C10 to C15 alkyl group, most preferably a C12 alkyl group.

    [0024] In the context of the present invention, these preferred compounds are also called "Cn (meth)acrylic acid ester" or "Cn (meth)acrylate", referring to compounds according to formula (I), wherein R1 and R2 represent hydrogen atoms, R3 represents a hydrogen atom or a methyl group, and R4 represents a Cn alkyl group.

    [0025] In another preferred embodiment, component A) comprises a mixture of C1 to C30 (meth)acrylic acid esters, more preferably a mixture of C10 to C15 (meth)acrylic acid esters. In the context of the present invention, the terms "a mixture of Cn to Cm (meth)acrylic acid esters" or "a mixture of Cn to Cm (meth)acrylates" refer to a mixture of compounds according to formula (I), wherein R1 and R2 represent hydrogen atoms, R3 represents a hydrogen atom or a methyl group, and R4 represents different Cn to Cm alkyl groups.

    [0026] In another preferred embodiment, component A) is a mixture comprising as component A1) a compound according to formula (II) or a mixture of compounds according to formula (II)

    wherein R6 and R7 independently represent a hydrogen atom or a group of the formula -COOR10, R8 represents a hydrogen atom or a methyl group, R9 represents a C1 to C5 alkyl group, a C2 to C5 alkenyl group, a C2 to C5 alkinyl group or a C3 to C5 cycloalkyl group, and R10 represents a hydrogen atom or a C1 to C5 alkyl group, a C2 to C5 alkenyl group, or a C2 to C5 alkinyl group;
    as component A2) a compound according to formula (III) or a mixture of compounds according to formula (III)

    wherein R11 and R12 independently represent a hydrogen atom or a group of the formula -COOR15, R13 represents a hydrogen atom or a methyl group, R14 represents a C6 to C15 alkyl, alkenyl, or alkinyl group or a C6 to C15 cycloalkyl group, and R15 represents a hydrogen atom or a C6 to C15 alkyl, alkenyl, or alkinyl group; and
    as component A3) a compound according to formula (IV) or a mixture of compounds according to formula (IV)

    wherein R16 and R17 independently represent a hydrogen atom or a group of the formula -COOR20, R18 represents a hydrogen atom or a methyl group, R19 represents a C16 to C30 alkyl, alkenyl, or alkinyl group or a C16 to C30 cycloalkyl group, and R20 represents a hydrogen atom or a C16 to C30 alkyl, alkenyl, or alkinyl group.

    [0027] Preferably, component A) is a mixture comprising
    0 to 15% by weight of component A1) relative to the total weight of component A), 50 to 100% by weight of component A2) relative to the total weight of component A), and
    0 to 50% by weight of component A3) relative to the total weight of component A), wherein the amounts of components A1) to A3) add up to 100% by weight relative to the total weight of component A).

    [0028] In a particularly preferred embodiment, component A1) consists of a mixture of C1 to C5 (meth)acrylic acid esters, component A2) consists of a mixture of C6 to C15 (meth)acrylic acid esters, and component A3) consists of a mixture C16 to C30 (meth)acrylic acid esters.

    [0029] The compounds according to formula (I) can be characterized based on their degree of linearity. In the context of the present invention the term "degree of linearity" refers to the amount of (meth)acrylic acid esters according to formula (I) having a linear alkyl, alkenyl, or alkinyl group as substituent R4 relative to the total weight of (meth)acrylic acid esters according to formula (I). It has been found that the viscosity of the polymer composition can be decreased even further, if R4 represents a linear alkyl, alkenyl, or alkinyl group. Therefore, in a preferred embodiment at least 30% by weight, more preferably at least 70% by weight, most preferably 100% by weight of the compounds according to formula (I) relative to the total weight of component A) have a linear alkyl, alkenyl, or alkinyl group as substituent R4. The same applies to the substituents R9, R14 and R19, correspondingly.

    [0030] Non-limiting examples of compounds of formula (I) in general and of formula (II) in particular include methyl-(meth)acrylate, ethyl-(meth)acrylate, n-propyl-(meth)acrylate, iso-propyl-(meth)acrylate, n-butyl-(meth)acrylate, tert-butyl-(meth)acrylate, pentyl-(meth)acrylate, cyclopentyl-(meth)acrylate, 2-proynyl-(meth)acrylate, allyl-(meth)acrylate, vinyl-(meth)acrylate, dimethylfumarate, and maleate.

    [0031] Non-limiting examples of compounds of formula (I) in general and of formula (III) in particular include hexyl-(meth)acrylate, 2-ethylhexyl-(meth)acrylate, heptyl-(meth)acrylate, 2-tert-butylheptyl-(meth)acrylate, octyl-(meth)acrylate, 3-isopropyl-heptyl-(meth)acrylate, nonyl-(meth)acrylate, decyl-(meth)acrylate, undecyl-(meth)acrylate, 5-methylundecyl-(meth)acrylate, dodecyl-(meth)acrylate, 2-methyldodecyl-(meth)acrylate, tridecyl-(meth)acrylate, 5-methyltridecyl-(meth)acrylate, tetradecyl-(meth)acrylate, pentadecyl-(meth)acrylate, oleyl-(meth)acrylate, 3-vinylcyclohexyl-(meth)acrylate, cyclohexyl-(meth)acrylate, bornyl-(meth)acrylate, and the corresponding fumarates and maleates.

    [0032] Non-limiting examples of compounds of formula (I) in general and of formula (IV) in particular include hexadecyl-(meth)acrylate, 2-methylhexadecyl-(meth)acrylate, heptadecyl-(meth)acrylate, 5-isopropylheptadecyl-(meth)acrylate, 4-tert-butyloctadecyl-(meth)acrylate, 5-ethyloctadecyl-(meth)acrylate, 3-isopropyloctadecyl-(meth)acrylate, octadecyl-(meth)acrylate, nonadecyl-(meth)acrylate, eicosyl-(meth)acrylate, cetyleicosyl-(meth)acrylate, stearyleicosyl-(meth)acrylate, docosyl-(meth)acrylate, eicosyltetratriacontyl-(meth)acrylate, 2,4,5-tri-tert-butyl-3-vinyl-cyclohexyl-(meth)acrylate, 2,3,4,5-tetra-tert-butylcyclohexyl-(meth)acrylate, and the corresponding fumarates and maleates.

    [0033] In a preferred embodiment component B) is a compound of formula (V) or a mixture of compounds of formula (V)

    wherein R21 is a C2 to C32 alkyl group.

    [0034] R21 is preferably a C6 to C20 alkyl group, more preferably a C6 to C12 alkyl group, most preferably a C8 alkyl group.

    [0035] Non-limiting examples of compounds of formula (V) include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 1-heneicosene, 1-docosene, 1-trocosene, 1-tetracosene, 1-pentacosene, 1-hexacosene, 1-heptacosene, 1-octacosene, 1-nonacosene, 1-triacontene, 1-hentriacontene, 1-dotriaconene.

    [0036] The reaction mixture prepared in step a) may additionally comprise a solvent. The solvent may be selected according to the polarity of the monomers used. Suitable solvents include, for example, aromatic hydrocarbons such as, for example, benzene, toluene, and xylenes; ethers such as, for example, tetrahydrofuran, diethyl ether, ethylene glycol and polyethylene glycol monoalkyl and dialkyl ethers; alkyl esters of acetic, propionic and butyric acids; mixed ester-ethers, such as, for example, monoalkyl ether-monoalkanoate esters of ethylene glycol; ketones such as, for example, acetone, butanone, pentanone and hexanone; alcohols such as, for example, methanol, ethanol, propanol and butanol. Oils such as, for example, hydrocracked oil, petroleum oil, polyalphaolefins, esters or polymers of the present invention may also be used.

    [0037] The Co(II) complex used in the inventive method acts as a catalytic chain transfer agent. By using a cobalt based catalytic chain transfer agent it has surprisingly been found that polymer compositions of extremely low viscosity can be produced. To achieve a kinematic viscosity of less than 25 mm2/s at 100°C according to ASTM D 445, the amount of Co(II) added to the reaction mixture in the form of a Co(II) complex is preferably 30 to 500 ppm by weight relative to the total weight of components A) and B), more preferably 30 to 100 ppm by weight, most preferably 50 to 100 ppm by weight.

    [0038] Suitable examples of Co(II) complexes of the present invention include complexes comprising Co(II) and at least one of the ligands according to formulae (VI) to (XI)











    wherein each R22 independently represents a phenyl group or a C1 to C12 alkyl group, or two R22 on adjacent carbon atoms together represent a C5 to C8 alkylene group; each R23 independently represents a hydrogen atom or a C1 to C12 alkyl group; each R24 independently represents a hydroxyl group or an amino group; each R25 independently represents a hydrogen atom, a C1 to C12 alkyl group, a phenyl group, a hydroxyphenyl group, or a C1 to C4 alkoxyphenyl group; and each n represents an integer 2 or 3.

    [0039] In a particularly preferred embodiment the Co(II) complex comprises Co(II) and a ligand of formula (XI). More preferably, the Co(II) complex is 5,10,15,20-tetraphenyl-porphine Co(II).

    [0040] The radical initiator used in the inventive method may be any free radical initiator suitable for use in radical polymerization reactions. Such radical initiators are well known in the art. Azo compounds are particularly preferred radical initiators.

    [0041] The total amount of the radical initiator added to the reaction mixture is at least 0.05% by weight relative to the total weight of components A) and B), preferably in the range of 0.1 to 3.5% by weight relative to the total weight of components A) and B). It has surprisingly been found that by varying the amount of initiator, polymer compositions of different viscosity and different pour points may be produced. To achieve a particularly low viscosity, the total amount of initiator added to the reaction mixture is preferably 0.5 to 1.75% by weight relative to the total weight of components A) and B).

    [0042] The radical initiator may be added to the reaction mixture in a step wise fashion to ensure that the radical initiator does not get depleted too quickly during long polymerization times. For example, a first dose of the radical initiator is added to the reaction mixture to start the polymerization reaction, then the reaction is allowed to proceed for a certain amount of time, then an additional dose initiator is added, and so on. The total amount added in all steps, however, should not exceed the preferred total amount of radical initiator mentioned above. The time interval between the addition of different doses of radical initiator may be in the range of 10 minutes to 5 hours, preferably 30 to 60 minutes.

    [0043] Examples of suitable radical initiators include azo-compounds such as azobisisobutylonitrile (AIBN), 2,2'-Azobis(2-methylbutyronitrile), 2-(2-cyanobutan-2-yldiazenyl)-2-methylbutanenitrile, and 1,1-azobiscyclohexanecarbonitrile; peroxy compounds such as methyl-ethyl-ketone peroxide, acetylacetone peroxide, dilauryl peroxide, tert-butyl per-2-ethylhexaneoate, ketone peroxide, tert-butyl peroctoate, methyl isobutyl ketone peroxide, cyclohexanone peroxide, dibenzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxyisopropylcarbonate, 2,5-bis(2-ethylhexanoylperoxy)-2,5-dimethylhexane, tert-butyl peroxy-2-ethylhexanoate, tert-butyl-peroxy-3,5,5-trimethylhexanoate, dicumyl peroxide, 1,1-bis(tert-butylperoxy)cyclohexane, 1,1 -bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, cumyl hydroperoxide, tert-butyl hydroperoxide, and bis(4-tert-butylcyclohexyl) peroxydicarbonate; and mixtures of the aforementioned compounds.

    [0044] The reaction mixture may be reacted in step d) at standard ambient pressure, reduced pressure or elevated pressure. The reaction temperature may in the range of -20°C to 200°C, preferably 50°C to 160°C, more preferably 80°C to 160°C.

    [0045] In a preferred embodiment, the addition of the radical initiator in step c) and the reaction in step d) take place in an inert gas atmosphere to prevent degradation of the radical initiator. Preferably, nitrogen gas is used as inert gas.

    [0046] The reaction may be allowed to proceed in step d) for up to 12 hours, preferably for 10 minutes to 12 hours, more preferably for 1 to 6 hours.

    [0047] In a particularly preferred embodiment of the present invention, the method comprises the steps of:
    1. a) preparing a reaction mixture consisting of 50 to 90% by weight of component A) and 10 to 50% by weight of component B) relative to the total weight of components A) and B);
    2. b) adding Co(II) in the form of a complex comprising Co(II) and a ligand according to formula (XI) at a concentration of 30 ppm to 100 ppm by weight of Co(II) relative to the total weight of components A) and B);
    3. c) adding 0.1 to 3.5% by weight relative to the total weight of components A) and B) of a radical initiator in a step-wise fashion; and
    4. d) reacting the reaction mixture at a temperature of 80°C to 160°C for 1 to 6 hours,
    wherein component A) is a mixture consisting of
    as component A1) 0 to 15% by weight of a C1 to C5 (meth)acrylic acid ester or a mixture of C1 to C5 (meth)acrylic acid esters relative to the total weight of component A),
    as component A2) 50 to 100% by weight of a C6 to C15 (meth)acrylic acid ester or a mixture of C6 to C15 (meth)acrylic acid esters relative to the total weight of component A), and
    as component A3) 0 to 50% by weight of a C16 to C30 (meth)acrylic acid esters or a mixture of C16 to C30 (meth)acrylic acid esters relative to the total weight of component A);
    and wherein component B) is a compound according to formula (V) or a mixture of compounds according to formula (V) wherein R21 is C6 to C12 alkyl group.

    [0048] In a second aspect, the present invention relates to the polymer composition obtained by the method as defined above. It has been found that with the inventive method, polymers with a kinematic viscosity of less than 25 mm2/s, measured at 100°C according to ASTM D 445 can be prepared. This result is even more surprising as it has been observed that polymers which are prepared by CCT polymerization using cobalt(II) as a catalytic chain transfer agent, but without the presence of a 1 -alkene component, have kinematic viscosity values which quickly reach a plateau, even by increasing the amount of cobalt catalytic chain transfer agent, and which are not getting to a lower kinematic viscosity value than 40 mm2/s at 100°C according to ASTM D 445 (see below Examples 6 to 9 in Table 1 and Table 1 continued). On the contrary, the inventive method, combining CCT polymerization using cobalt(II) as a catalytic chain transfer agent in the presence of a 1-alkene component, surprisingly allows preparing polymer compositions with special properties, namely, a kinematic viscosity of less than 25 mm2/s measured at 100°C according to ASTM D 445 (Examples 2 to 5 in Table 1).

    [0049] In a third aspect, the present invention relates to the use of the polymer composition obtained by the claimed method as a lubricant base fluid for lubricants.

    [0050] In a fourth aspect, the present invention relates to a lubricant base fluid comprising the polymer composition obtained by the claimed method.

    [0051] In a fifth aspect, the present invention relates to the use of a Co(II) complex as catalytic chain transfer agent for the polymerization of a reaction mixture comprising an ethylenically unsaturated monomer or a mixture of ethylenically unsaturated monomers, a radical initiator, and a 1-alkene or a mixture of 1-alkenes, wherein the total amount of the radical initiator added to the reaction mixture is at least 0.05% by weight relative to the total weight of the ethylenically unsaturated monomer or mixture of ethylenically unsaturated monomers and the 1-alkene or mixture of 1-alkenes. The ethylenically unsaturated monomer and 1-alkene correspond to components A) and B) as described above. The Co(II) complex and radical initiator may be any of the Co(II) complexes and radical initiators described above. According the fifth aspect of the invention, the Co(II) complex may be used as catalytic chain transfer agent to prepare extremely low-viscosity polymers.

    [0052] The method for the preparation of a polymer composition is the method to prepare a polymer composition as described above. The Co(II) complex that is used as catalyst is the Co(II) complex as described above.

    Examples



    [0053] In the following examples, Isodecyl-methacrylate (IDMA) is a mixture consisting of 98.7% by weight C10 methacrylate, 0.8% by weight C12 methacrylate, and 0.5% by weight C14 methacrylate. The degree of linearity of IDMA is approximately 0%.

    [0054] Methacrylate from LIAL® 125 alcohol (LIMA) is a mixture consisting of 24.3% by weight C12 methacrylate, 29.4% by weight C13 methacrylate, 28.4% by weight C14 methacrylate, and 17.9% by weight C15 methacrylate. The degree of linearity of LIMA is approximately 40%.

    [0055] Lauryl methacrylate (LMA) is a mixture consisting of 72.2% by weight C12 methacrylate, and 27.8% by weight C14 methacrylate. The degree of linearity of LIAL is approximately 100%.

    Example 1 (Comparative example)



    [0056] Example 1 is equal to Example 1 as disclosed in US 5,691,284 and was prepared as follows:
    141 g of 1-decene was heated to 160°C in a reaction vessel. A mixture of 113 g of IDMA and 135 g of LIMA was fed in over 4 hours. At the end of the feed, the batch was polymerized for another 12 hours. During the entire reaction time of 16 hours, with the exception of the last hour, di-tert-butyl peroxide was added at 30-minute intervals (here, 30 portions, total amount 2.8% by weight relative to the total weight of 1-decene and methacrylate monomers).

    Example 2



    [0057] 109 g of 1 -decene, 87 g of IDMA, and 104 g of LIMA were charged into a 500 mL 4-necked round bottom flask. 0.225 g of 5,10,15,20-Tetraphenyl Porphine Cobalt(II) was then added to the flask. The contents of the flask were mixed using an overhead stirrer, inerted with nitrogen, and heated to 140°C. Once the mixture reached temperature and the cobalt catalyst appeared to be dissolved, 2.8 g of initiator solution comprising 50% by weight 2,2-bis-tert-butyl-peroxybutane was added to the flask using a syringe through a rubber septum. The reaction was allowed to proceed for 30 minutes. Five additional shots of 2.8 g of initiator solution were added 30 minutes apart.

    [0058] Residual monomer was measured by gas chromatography on the resultant polymers to ensure full monomer conversion.

    [0059] Residual amounts of unreacted 1-decene were removed by via rotary evaporation at 100°C and less than 15 mm Hg pressure.

    Example 3



    [0060] 109 g of 1 -decene, 87 g of IDMA, and 104 g of LIMA were charged into a 500 mL 4-necked round bottom flask. 0.225 g of 5,10,15,20-Tetraphenyl Porphine Cobalt(II) was then added to the flask. The contents of the flask were mixed using an overhead stirrer, inerted with nitrogen, and heated to 140°C. Once the mixture reached temperature and the cobalt catalyst appeared to be dissolved, 1.1 g of initiator solution comprising 50% by weight 2,2-bis-tert-peroxybutane was added to the flask using a syringe through a rubber septum. The reaction was allowed to proceed for 30 minutes. Five additional shots of 1.1 g of initiator solution were added 30 minutes apart.

    [0061] Residual monomer was measured by gas chromatography on the resultant polymers to ensure full monomer conversion.

    [0062] Residual amounts of unreacted 1-decene were removed by via rotary evaporation at 100°C and less than 15 mm Hg pressure.

    Example 4



    [0063] 90 g of 1-decene and 210 g of LMA were charged into a 500 mL 4-necked round bottom flask. 0.225 g of 5,10,15,20-Tetraphenyl Porphine Cobalt(II) was then added to the flask. The contents of the flask were mixed using an overhead stirrer, inerted with nitrogen, and heated to 140°C. Once the mixture reached temperature and the cobalt catalyst appeared to be dissolved, 1.1 g of initiator solution comprising 50% by weight 2,2-bis-tert-butyl-peroxybutane was added to the flask using a syringe through a rubber septum. The reaction was allowed to proceed for 30 minutes. Five additional shots of 1.1 g of initiator solution were added 30 minutes apart.

    [0064] Residual monomer was measured by gas chromatography on the resultant polymers to ensure full monomer conversion.

    [0065] Residual amounts of unreacted 1-decene were removed by via rotary evaporation at 100°C and less than 15 mm Hg pressure

    Example 5



    [0066] 90 g of 1-decene and 210 g of LMA were charged into a 500 mL 4-necked round bottom flask. 0.225 g of 5,10,15,20-Tetraphenyl Porphine Cobalt(II) was then added to the flask. The contents of the flask were mixed using an overhead stirrer, inerted with nitrogen, and heated to 140°C. Once the mixture reached temperature and the cobalt catalyst appeared to be dissolved, 1.1 g of initiator solution comprising 50% by weight of 2,2-bis-tert-butyl-peroxybutane was added to the flask using a syringe through a rubber septum. The reaction was allowed to proceed for 30 minutes. Five additional shots of 1.1 g of initiator solution were added 30 minutes apart.

    [0067] Residual monomer was measured by gas chromatography on the resultant polymers to ensure full monomer conversion.

    [0068] Residual amounts of unreacted 1-decene were removed by via rotary evaporation at 100°C and less than 15 mm Hg pressure

    Comparative example 6



    [0069] 250 g of LMA were charged into a 500 mL 4-necked round bottom flask. 0.188 g of 5,10,15,20-Tetraphenyl Porphine Cobalt(II) was then added to the flask. The contents of the flask were mixed using an overhead stirrer, inerted with nitrogen, and heated to 90°C. Once the mixture reached temperature and the cobalt catalyst appeared to be dissolved, 1 g of initiator solution comprising 25% by weight 2-(2-cyanobutan-2-yldiazenyl)-2-methylbutanenitrile (Vazo67) in diisobutyl ketone was added to the flask using a syringe through a rubber septum. The reaction was allowed to proceed for 60 minutes. Two additional shots of 1 g of initiator solution were added 60 minutes apart. The reaction was allowed to hold for one hour after the final addition of initiator.

    Measurements of viscosity, molecular weight, and sonic shear stability



    [0070] The kinematic viscosities of the polymers were measured according to ASTM D 445. The polymer molecular weights were measured by gel permeation chromatography (GPC) calibrated using poly(methyl-methacrylate) standards. The sonic shear stability was determined according to ASTM D 5621. The pour point was determined according to ASTM D 6749. The viscosity index was determined according to ASTM D 2270.

    [0071] Examples 2 to 5 demonstrate that the use of a cobalt based catalytic chain transfer agent for the polymerization of methacrylate and 1-alkene monomers yields polymers with a kinematic viscosity of less than 25 mm2/s measured at 100°C according to ASTM D 445 (table 1). Comparative example 1 demonstrates that this is not achievable without the cobalt based chain transfer agent. An additional beneficial feature when using the method of the present invention is a greater efficiency of the 1-decene to reduce viscosity, such that only half the charge of 1-decene is required in example 5 as compared to comparative example 1. These features demonstrate the utility of the inventive method to enable the preparation of polymers with lower viscosities and a high methacrylate to 1-alkene ratio.

    [0072] Molecular weight data show that the extremely low molecular weight methacrylate-decene polymers of examples 2 to 5 have a degree of polymerization of about 5, whereas previous cobalt based catalytic chain transfer polymerizations of lauryl-methacrylate without the alpha-olefin comonomer showed an average degree of polymerization of about 9. A direct comparison of example 4 and comparative example 6 shows the impact of incorporating 1-decene in the presence of a cobalt based catalytic chain transfer agent on polymer Mw (from 4400 g/mol to 1800 g/mol) and product viscosity at 100°C (from 40 mm2/s to 9 mm2/s). Indeed, it was observed that polymers which are prepared by CCT polymerization using cobalt(II) as a catalytic chain transfer agent, but without the presence of a 1 -alkene component, have kinematic viscosity values which quickly reach a plateau, even by increasing the amount of cobalt catalytic chain transfer agent, and which are not getting to a lower kinematic viscosity value than 40 mm2/s at 100°C according to ASTM D 445 (see below Examples 6 to 9 in Table 1 and Table 1 continued). Said decreasing activity of the Cobalt catalytic transfer agent was also observed and commented in the publication Smirnov et al, Polym. Sci. 1981, A23, 1158.

    [0073] On the contrary, the inventive method, combining CCT polymerization using cobalt(II) as a catalytic chain transfer agent in the presence of a 1-alkene component, surprisingly allows preparing polymer compositions with special properties, namely, a kinematic viscosity of less than 25 mm2/s measured at 100°C according to ASTM D 445 (Examples 2 to 5 in Table 1).

    [0074] The direct comparison of examples 2 and 3 shows that a reduction in the amount of radical initiator yields a lower viscosity of the product polymers. This is contrary to what is normally observed in free radical polymerization, where a reduction in polymerization initiator typically results in higher viscosity. This effect is beneficial in helping reduce the overall amount of initiator by-products that may be present in the product polymer. Examples 2 and 3 also show that a reduction in the amount of radical initiator lowers the pour point of the product polymer.

    [0075] As the different pour points of examples 2 to 5 indicate, the pour point may also be tuned by varying the composition of the monomer mixture, in particular by varying the amount of 1-alkene.





    [0076] Table 2 shows the properties of two commercially available group IV polyalphaolefin base oils (Spectrasyn® 10) and ester-based fluids (Esterex® TM101) in comparison to examples 3 and 4. The data show that examples 3 and 4 deliver viscosity indices greater than those of the commercial products, and are able to provide base fluids with excellent pour points.
    Table 2: Comparison of commercial base fluids to examples 3 and 4.
    ProductSpectrasyn® 10Esterex® TM101Example 3Example 4
    Kinematic viscosity at 100°C [mm2/s] 10 9.8 11.6 9.07
    Kinematic viscosity at 40°C [mm2/s] 66 89 84.1 54.5
    Viscosity Index 137 86 129 147
    Pour Point [°C] -48 -36 -48 -27



    Claims

    1. A method for preparing a polymer composition having a kinematic viscosity of less than 25 mm2/s measured at 100°C according to ASTM D 445, said method comprising the steps of:

    a) preparing a reaction mixture comprising
    as component A) an ethylenically unsaturated monomer or a mixture of ethylenically unsaturated monomers, and
    as component B) a 1 -alkene or a mixture of 1 -alkenes;

    b) adding a Co(II) complex as a catalytic chain transfer agent to the reaction mixture;

    c) adding a radical initiator; and

    d) reacting the reaction mixture to obtain the polymer composition,
    wherein the total amount of the radical initiator added to the reaction mixture is at least 0.05% by weight relative to the total weight of components A) and B);
    wherein the component A) is a compound of formula (I) or a mixture of compounds of formula (I)

    wherein R1 and R2 independently represent a hydrogen atom or a group of the formula -COOR5, R3 represents a hydrogen atom or a methyl group, R4 represents a C1 to C30 alkyl group, a C2 to C30 alkenyl group, a C2 to C30 alkinyl group or a C3 to C30 cycloalkyl group, and R5 represents a hydrogen atom or a C1 to C30 alkyl group, a C2 to C30 alkenyl group, or a C2 to C30 alkinyl group, and
    wherein the reaction mixture comprises at least 50% by weight of component A) relative to the total weight of components A) and B).


     
    2. The method according to claim 1, characterized in that component B) is a compound of formula (V) or a mixture of compounds of formula (V)

    wherein R21 is a C2 to C32 alkyl group.
     
    3. The method according to claim 1 or 2, characterized in that reaction mixture comprises at least 10% by weight of component B) relative to the total weight of components A) and B).
     
    4. The method according to any one of claims 1 to 3, characterized in that the Co(II) complex comprises Co(II) and at least one of the ligands according to formulae (VI) to (XI)











    wherein each R22 independently represents a phenyl group or a C1 to C12 alkyl group, or two R22 on adjacent carbon atoms together represent a C5 to C8 alkylene group; each R23 independently represents a hydrogen atom or a C1 to C12 alkyl group; each R24 independently represents a hydroxyl group or an amino group; each R25 independently represents a hydrogen atom, a C1 to C12 alkyl group, a phenyl group, a hydroxyphenyl group, or a C1 to C4 alkoxyphenyl group; and each n represents an integer 2 or 3.
     
    5. The method according to any one of claims 1 to 4, characterized in that the amount of Co(II) added to the reaction mixture is 30 to 500 ppm by weight relative to the total weight of components A) and B).
     
    6. The method according to any one of claims 1 to 5, characterized in that total amount of radical initiator added to the reaction mixture is 0.1 to 3.5% by weight relative to the total weight of components A) and B).
     
    7. Polymer composition obtainable by the method as defined in any one of claims 1 to 6.
     
    8. Use of the polymer composition of claim 7 as a lubricant base fluid for lubricants.
     
    9. Lubricant base fluid comprising the polymer composition of claim 7.
     
    10. Use of a Co(II) complex as catalytic chain transfer agent for the polymerization of a reaction mixture comprising an ethylenically unsaturated monomer or a mixture of ethylenically unsaturated monomers, a radical initiator, and a 1-alkene or a mixture of 1-alkenes, wherein the total amount of the radical initiator added to the reaction mixture is at least 0.05% by weight relative to the total weight of the ethylenically unsaturated monomer or mixture of ethylenically unsaturated monomers and the 1-alkene or mixture of 1-alkenes; and
    wherein the ethylenically unsaturated monomer is a compound of formula (I) or a mixture of compounds of formula (I)

    wherein R1 and R2 independently represent a hydrogen atom or a group of the formula -COOR5, R3 represents a hydrogen atom or a methyl group, R4 represents a C1 to C30 alkyl group, a C2 to C30 alkenyl group, a C2 to C30 alkinyl group or a C3 to C30 cycloalkyl group, and R5 represents a hydrogen atom or a C1 to C30 alkyl group, a C2 to C30 alkenyl group, or a C2 to C30 alkinyl group, and
    wherein the reaction mixture comprises at least 50% by weight of the ethylenically unsaturated monomer or the mixture of ethylenically unsaturated monomers relative to the total weight of the ethylenically unsaturated monomer or the mixture of ethylenically unsaturated monomers and the 1-alkene or the mixture of 1-alkenes.
     


    Ansprüche

    1. Verfahren zur Herstellung einer Polymerzusammensetzung mit einer bei 100 °C gemäß ASTM D 445 gemessenen kinematischen Viskosität von weniger als 25 mm2, wobei das Verfahren folgende Schritte umfasst:

    a) Herstellen einer Reaktionsmischung, umfassend als Komponente A) ein ethylenisch ungesättigtes Monomer oder eine Mischung von ethylenisch ungesättigten Monomeren und
    als Komponente B) ein 1-Alken oder eine Mischung von 1-Alkenen;

    b) Zugeben eines Co(II)-Komplexes als katalytisches Kettenübertragungsmittel zur Reaktionsmischung;

    c) Zugeben eines Radikalinitiators und

    d) Umsetzen der Reaktionsmischung zum Erhalt der Polymerzusammensetzung,
    wobei die Gesamtmenge des zu der Reaktionsmischung gegebenen Radikalinitiators mindestens 0,05 Gew.-%, bezogen auf das Gesamtgewicht der Komponenten A) und B), beträgt;
    wobei es sich bei Komponente A) um eine Verbindung der Formel (I) oder eine Mischung von Verbindungen der Formel (I) handelt:

    wobei R1 und R2 unabhängig voneinander für ein Wasserstoffatom oder eine Gruppe der Formel -COOR5 stehen, R3 für ein Wasserstoffatom oder eine Methylgruppe steht, R4 für eine C1- bis C30-Alkylgruppe, eine C2- bis C30-Alkenylgruppe, eine C2- bis C30-Alkinylgruppe oder eine C3- bis C30-Cycloalkylgruppe steht und R5 für ein Wasserstoffatom oder eine C1- bis C30-Alkylgruppe, eine C2- bis C30-Alkenylgruppe oder eine C2- bis C30-Alkinylgruppe steht, und
    wobei die Reaktionsmischung mindestens 50 Gew.-% Komponente A), bezogen auf das Gesamtgewicht der Komponenten A) und B), umfasst.


     
    2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass es sich bei Komponente B) um eine Verbindung der Formel (V) oder eine Mischung von Verbindungen der Formel (V) handelt:

    wobei R21 für eine C2- bis C32-Alkylgruppe steht.
     
    3. Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass die Reaktionsmischung mindestens 10 Gew.-% Komponente B), bezogen auf das Gesamtgewicht der Komponenten A) und B), umfasst.
     
    4. Verfahren nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, dass der Co(II)-Komplex Co(II) und mindestens einen der Liganden gemäß den Formeln (VI) bis (XI) umfasst:











    wobei R22 jeweils unabhängig voneinander für eine Phenylgruppe oder eine C1- bis C12-Alkylgruppe steht oder zwei R22 an benachbarten Kohlenstoffatomen zusammen für eine C5- bis C8-Alkylengruppe stehen; R23 jeweils unabhängig voneinander für ein Wasserstoffatom oder eine C1- bis C12-Alkylgruppe steht; R24 jeweils unabhängig voneinander für eine Hydroxylgruppe oder eine Aminogruppe steht; R25 jeweils unabhängig voneinander für ein Wasserstoffatom, eine C1- bis C12-Alkylgruppe, eine Phenylgruppe, eine Hydroxyphenylgruppe oder eine C1- bis C4-Alkoxyphenylgruppe steht und n jeweils für eine ganze Zahl mit einem Wert von 2 oder 3 steht.
     
    5. Verfahren nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, dass die zur Reaktionsmischung gegebene Menge von Co(II) 30 bis 500 Gew.-ppm, bezogen auf das Gesamtgewicht der Komponenten A) und B), beträgt.
     
    6. Verfahren einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, dass die Gesamtmenge des zu der Reaktionsmischung gegebenen Radikalinitiators 0,1 bis 3,5 Gew.-%, bezogen auf das Gesamtgewicht der Komponenten A) und B), beträgt.
     
    7. Polymerzusammensetzung, die durch das Verfahren gemäß einem der Ansprüche 1 bis 6 erhältlich ist.
     
    8. Verwendung der Polymerzusammensetzung nach Anspruch 7 als Schmiermittel-Basisfluid für Schmiermittel.
     
    9. Schmiermittel-Basisfluid, umfassend die Polymerzusammensetzung nach Anspruch 7.
     
    10. Verwendung eines Co(II)-Komplexes als katalytisches Kettenübertragungsmittel zur Polymerisation einer Reaktionsmischung, die ein ethylenisch ungesättigtes Monomer oder eine Mischung von ethylenisch ungesättigten Monomeren, einen Radikalinitiator und ein 1-Alken oder eine Mischung von 1-Alkenen umfasst,
    wobei die Gesamtmenge des zu der Reaktionsmischung gegebenen Radikalinitiators mindestens 0,05 Gew.-%, bezogen auf das Gesamtgewicht des ethylenisch ungesättigten Monomers bzw. der Mischung von ethylenisch ungesättigten Monomeren und des 1-Alkens bzw. der Mischung von 1-Alkenen, beträgt und
    wobei es sich bei dem ethylenisch ungesättigten Monomer um eine Verbindung der Formel (I) oder eine Mischung von Verbindungen der Formel (I) handelt:

    wobei R1 und R2 unabhängig voneinander für ein Wasserstoffatom oder eine Gruppe der Formel -COOR5 stehen, R3 für ein Wasserstoffatom oder eine Methylgruppe steht, R4 für eine C1- bis C30-Alkylgruppe, eine C2- bis C30-Alkenylgruppe, eine C2- bis C30-Alkinylgruppe oder eine C3- bis C30-Cycloalkylgruppe steht und R5 für ein Wasserstoffatom oder eine C1- bis C30-Alkylgruppe, eine C2- bis C3o-Alkenylgruppe oder eine C2- bis C30-Alkinylgruppe steht, und
    wobei die Reaktionsmischung mindestens 50 Gew.-% des ethylenisch ungesättigten Monomers bzw. der Mischung von ethylenisch ungesättigten Monomeren, bezogen auf das Gesamtgewicht des ethylenisch ungesättigten Monomers bzw. der Mischung von ethylenisch ungesättigten Monomeren und des 1-Alkens bzw. der Mischung von 1-Alkenen, umfasst.
     


    Revendications

    1. Procédé pour la préparation d'une composition de polymère possédant une viscosité cinématique de moins de 25 mm2/s mesurée à 100 °C selon la norme ASTM D 445, ledit procédé comprenant les étapes de :

    a) préparation d'un mélange réactionnel comprenant en tant que composant A), un monomère éthyléniquement insaturé ou un mélange de monomères éthyléniquement insaturés, et
    en tant que composant B), un 1-alcène ou un mélange de 1-alcènes ;

    b) ajout au mélange réactionnel d'un complexe de Co(II) en tant que qu'un agent catalytique de transfert de chaîne ;

    c) ajout d'un initiateur de radicaux ; et

    d) mise en réaction du mélange réactionnel pour obtenir la composition de polymère,
    la quantité totale de l'initiateur de radicaux ajouté au mélange réactionnel étant d'au moins 0,05 % en poids par rapport au poids total des composants A) et B) ;
    le composant A) étant un composé de formule (I) ou un mélange de composés de formule (I)

    R1 et R2 représentant indépendamment un atome d'hydrogène ou un groupe de formule -COOR5, R3 représentant un atome d'hydrogène ou un groupe méthyle, R4 représentant un groupe C1-30-alkyle, un groupe C2-30-alcényle, un groupe C2-30-alcynyle ou un groupe C2-30-cycloalkyle, et R5 représentant un atome d'hydrogène ou un groupe C1-30-alkyle, un groupe C2-30-alcényle, ou un groupe C2-30-alcynyle, et
    le mélange réactionnel comprenant au moins 50 % en poids de composant A) par rapport au poids total des composants A) et B).


     
    2. Procédé selon la revendication 1, caractérisé en ce que le composant B) est un composé de formule (V) ou un mélange de composés de formule (V)

    R21 étant un groupe C2-32-alkyle.
     
    3. Procédé selon la revendication 1 ou 2, caractérisé en ce que le mélange réactionnel comprend au moins 10 % en poids de composant B) par rapport au poids total des composants A) et B).
     
    4. Procédé selon l'une quelconque des revendications 1 à 3, caractérisé en ce que le complexe de Co(II) comprend du Co(II) et au moins un des ligands selon les formules (VI) à (XI)











    chaque R22 représentant indépendamment un groupe phényle ou un groupe C1-12-alkyle, ou deux R22 sur des atomes de carbone adjacents représentant un groupe C5-8-alkylène ; chaque R23 représentant indépendamment un atome d'hydrogène ou un groupe C1-12-alkyle ; chaque R24 représentant indépendamment un groupe hydroxyle ou un groupe amino ; chaque R25 représentant indépendamment un atome d'hydrogène, un groupe C1-12-alkyle, un groupe phényle, un groupe hydroxyphényle, ou un groupe C1-4-alcoxyphényle ; et chaque n représentant un entier 2 ou 3.
     
    5. Procédé selon l'une quelconque des revendications 1 à 4, caractérisé en ce que la quantité de Co(II) ajouté au mélange réactionnel est de 30 à 500 ppm en poids par rapport au poids total des composants A) et B).
     
    6. Procédé selon l'une quelconque des revendications 1 à 5, caractérisé en ce que la quantité totale d'initiateur de radicaux ajouté au mélange réactionnel est de 0,1 à 3,5 % en poids par rapport au poids total des composants A) et B).
     
    7. Composition de polymère pouvant être obtenue par le procédé tel que défini selon l'une quelconque des revendications 1 à 6.
     
    8. Utilisation de la composition de polymère selon la revendication 7 en tant que fluide lubrifiant de base pour des lubrifiants.
     
    9. Fluide lubrifiant de base comprenant la composition de polymère selon la revendication 7.
     
    10. Utilisation d'un complexe de Co(II) en tant qu'agent catalytique de transfert de chaîne pour la polymérisation d'un mélange réactionnel comprenant un monomère éthyléniquement insaturé ou un mélange de monomères éthyléniquement insaturés, un initiateur de radicaux, et un 1-alcène ou un mélange de 1-alcènes, la quantité totale de l'initiateur de radicaux ajouté au mélange réactionnel étant d'au moins 0,05 % en poids par rapport au poids total du monomère éthyléniquement insaturé ou du mélange de monomères éthyléniquement insaturés et du 1-alcène ou du mélange de 1-alcènes ; et
    le monomère éthyléniquement insaturé étant un composé de formule (I) ou un mélange de composés de formule (I)

    R1 et R2 représentant indépendamment un atome d'hydrogène ou un groupe de formule -COOR5, R3 représentant un atome d'hydrogène ou un groupe méthyle, R4 représentant un groupe C1-30-alkyle, un groupe C2-30-alcényle, un groupe C2-30-alcynyle ou un groupe C2-30-cycloalkyle, et R5 représentant un atome d'hydrogène ou un groupe C1-30-alkyle, un groupe C2-30-alcényle, ou un groupe C2-30-alcynyle, et
    le mélange réactionnel comprenant au moins 50 % en poids du monomère éthyléniquement insaturé ou du mélange de monomères éthyléniquement insaturés par rapport au poids total du monomère éthyléniquement insaturé ou du mélange de monomères éthyléniquement insaturés et du 1-alcène ou du mélange de 1-alcènes.
     






    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