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Polyolefin/Thermoplastic Polyurethane Compositions Europäisches Patentamt *EP000994919B1* (19) European Patent Office Office européen des brevets (11) EP 0 994 919 B1 (12) EUROPEAN PATENT SPECIFICATION (45) Date of publication and mention (51) Int Cl.7: C08L 23/02 of the grant of the patent: // C08L23:02 23.06.2004 Bulletin 2004/26 (86) International application number: (21) Application number: 98942676.2 PCT/EP1998/004979 (22) Date of filing: 08.07.1998 (87) International publication number: WO 1999/002603 (21.01.1999 Gazette 1999/03) (54) POLYOLEFIN/THERMOPLASTIC POLYURETHANE COMPOSITIONS MADE FROM HYDROXY-TERMINATED POLYDIENE POLYMERS POLYOLEFIN/THERMOPLASTISCHE-POLYURETHANZUSAMMENSETZUNGEN AUS HYDROXYLENDGRUPPENHALTIGEN POLYDIENPOLYMEREN COMPOSITIONS DE POLYOLEFINE/POLYURETHANE THERMOPLASTIQUE PREPAREES A PARTIR DE POLYMERES DE POLYDIENE A TERMINAISON HYDROXY (84) Designated Contracting States: (72) Inventor: CENENS, Jozef, Lucien, Rudolf BE DE ES FR GB IT NL SE Sugar Land, TX 77478 (US) (30) Priority: 10.07.1997 US 52216 P (74) Representative: Kortekaas, Marcellinus C. J. A. et al (43) Date of publication of application: KRATON Polymers Research B.V., 26.04.2000 Bulletin 2000/17 P.O. Box 37666 1030 BH Amsterdam (NL) (73) Proprietor: KRATON Polymers Research B.V. 1031 CM Amsterdam (NL) (56) References cited: EP-A- 0 347 794 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). EP 0 994 919 B1 Printed by Jouve, 75001 PARIS (FR) EP 0 994 919 B1 Description [0001] This invention relates to thermoplastic polyurethane/polyolefin compositions. More specifically, the invention relates to compatible thermoplastic polyurethane/polyolefin compositions. 5 [0002] Thermoplastic Polyurethanes (TPU) are reaction products of 1) a polymeric diol, 2) a diisocyanate, and 3) a chain extender. The diol is usually either a polyether or a polyester of about 1000 to 4000 number average molecular weight. The diisocyanate used is commonly 4,4-diphenylmethane diisocyanate (MDI) but many other isocyanates may also be used. The chain extender is a low molecular weight diol, usually 1,4-butane diol (BDO), but in other work it has been found to be advantageous to use branched diols such as 2-ethyl-1,3-hexane diol (PEP). TPU's such as these 10 have been considered for use as additives to polypropylene to improve impact resistance and to improve adhesion of paint to the modified polypropylene. However, because of the polar nature of polyethers and polyesters, these con- ventional TPU's are too polar to be broadly compatible with polypropylene and other polyolefins and other non-polar polymers such as EPDM and butadiene and isoprene rubbers. This incompatibility is the reason why their blends frequently delaminate and therefore are not useful. From EP0347794A1 a thermoplastic resinous composition is known 15 that comprises a polyolefin, a thermoplastic polyurethane component and a compatibilizing amount of at least one modified polyolefin. This reference does not suggest how to obtain a polyolefin/thermoplastic polyurethane composition that is compatible without the need of a compatibilizer. The problem the present invention sets out to solve is to provide a compatible polyolefin/thermoplastic polyurethane composition. Such a composition has now surprisingly been found. [0003] Therefore, the present invention relates to a polyolefin/thermoplastic polyurethane composition which com- 20 prises: (a) from 99 to 80 percent by weight (%wt) of a polyolefin, and (b) from 1 to 20 %wt of a thermoplastic polyurethane composition having an OH/NCO molar ratio of 0.9 to 1.1 which is comprised of: 25 (1) from 90 to 40 %wt of a hydrogenated polydiene diol having a hydroxyl equivalent weight of 750 to 10,000, (2) from 5 to 50 %w of a diisocyanate, and (3) from 4 to 14 %wt of a chain extender having a functional group equivalent weight of from 30 to 300. 30 [0004] Hydroxy functional polydiene polymers (polydiene diols) are known. United States Patent No. 5,393,843 dis- closes that formulations containing these polymers, a melamine resin, and an acid catalyst can be cured by baking under normal bake conditions. This same patent also discloses that these polymers can be mixed with isocyanates to yield polyurethane compositions that cure at ambient temperature. It is known that, for instance, hydrogenated polyb- utadiene diols (EB diol) can be crosslinked by reaction with polyisocyanates at stoichiometry near 1/1 NCO/OH (NCO 35 represents the isocyanate functionality which is active in the crosslinking reaction and OH represents the hydroxyl functionality). [0005] The preferred polyolefins are polypropylene homopolymer and polypropylene copolymers containing at least 60 %wt of polymerized propylene units. [0006] The preferred polydiene diol is a hydrogenated polybutadiene diol. Preferably, the polydiene diol has a hy- 40 droxyl equivalent weight of 750 to 5000. [0007] The preferred chain extenders are alkyl-substituted aliphatic diols preferably C1-C8 alkyl-substituted aliphatic diols such as 2-ethyl-1,3-hexane diol (PEP diol), 2,2,4-trimethyl-1,3-pentane diol (TMPD diol), and 2-ethyl-2-butyl- 1,3-propane diol (BEPD diol). The aliphatic diol is preferably a C3-C50 aliphatic diol, more preferably a C3-C12 aliphatic diol. 45 [0008] Hydroxy functional polydiene polymers and other polymers containing ethylenic unsaturation can be prepared by copolymerizing one or more olefins, particularly diolefins, by themselves or with one or more alkenyl aromatic hy- drocarbon monomers. The copolymers may, of course, be random, tapered, block or a combination of these, as well as linear, radial or star. [0009] The hydroxy functional polydiene polymers may be prepared using anionic initiators or polymerization cata- 50 lysts. Such polymers may be prepared using bulk, solution or emulsion techniques. When polymerized to high molecular weight, the polymer will, generally, be recovered as a solid such as a crumb, a powder, or a pellet. When polymerized to low molecular weight, it may be recovered as a liquid such as in the present invention. [0010] In general, when solution anionic techniques are used, (co)polymers of conjugated diolefins, optionally with vinyl aromatic hydrocarbons, are prepared by contacting the monomer or monomers to be polymerized simultaneously 55 or sequentially with an anionic polymerization initiator such as group IA metals, their alkyls, amides, silanolates, naph- thalides, biphenyls or anthracenyl derivatives. It is preferred to use an organo alkali metal (such as sodium or potassium) compound in a suitable solvent at a temperature in the range from -150°Cto300°C, preferably at a temperature in the range from 0°Cto100°C. Particularly effective anionic polymerization initiators are organo lithium compounds having 2 EP 0 994 919 B1 the general formula: RLin 5 wherein R is an aliphatic, cycloaliphatic, aromatic or alkyl-substituted aromatic hydrocarbon radical having from 1 to about 20 carbon atoms and n is an integer of 1 to 4. [0011] Conjugated diolefins (dienes) which may be polymerized anionically include those conjugated diolefins con- taining from 4 to 24 carbon atoms such as 1,3-butadiene, isoprene, piperylene, methylpentadiene, phenyl-butadiene, 10 3,4-dimethyl-1,3-hexadiene, and 4,5-diethyl-1,3-octadiene. Isoprene and butadiene are the preferred conjugated diene monomers for use in the present invention because of their low cost and ready availability. Alkenyl (vinyl) aromatic hydrocarbons that may be copolymerized include vinyl aryl compounds such as styrene, various alkyl-substituted sty- renes, alkoxy-substituted styrenes, vinyl naphthalene and alkyl-substituted vinyl naphthalenes. [0012] The hydroxy functional polydiene polymers may have number average molecular weights of from 1500 to 15 20,000. Lower molecular weights require excessive crosslinking whereas higher molecular weights cause very high viscosity, making processing very difficult. Most preferably, the polymer is a predominately linear diol having a number average molecular weight of from 1500 to 10,000 (hydroxyl equivalent weight of 750 to 5000 because its a diol and has two hydroxyls) because this offers the best balance between the cost of the polymer, achieving good processing behavior, and achieving the right balance of mechanical properties in the final thermoplastic polyurethane. The average 20 functionality of the polydiene diol is preferably from 1.8 to 2.0, more preferably 1.9 to 2.0. [0013] Hydrogenated polybutadiene diols are preferred for use herein because they are easily prepared, they have low glass transition temperature, and they have excellent weatherability. The diols, dihydroxylated polydienes, are typically synthesized by anionic polymerization of conjugated diene hydrocarbon monomers with lithium initiators. This process is well known as described in U.S. Patents Nos. 4,039,593 and Re. 27,145. Polymerization commences with 25 a monolithium or dilithium initiator that builds a living polymer backbone at each lithium site. [0014] Polydiene diols used in this invention may be prepared anionically with a dilithium initiator such as described in United States Patents Nos. 5,391,663, 5,393,843, 5,405,911, and 5,416,168. The polydiene polymer can be made using a dilithium initiator, such as the compound formed by reaction of two moles of sec-butyllithium with one mole of diisopropenylbenzene. This diinitiator is typically used to polymerize a diene in a solvent typically composed of 90%wt 30 cyclohexane and 10%wt diethylether. The molar ratio of diinitiator to monomer determines the molecular weight of the polymer. The living polymer is then capped with two moles of ethylene oxide and terminated with two moles of methanol to yield the desired polydiene diol. [0015] Polydiene diol polymers can also be made using a mono-lithium initiator that contains a hydroxyl group which has been blocked as the silyl ether.
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