Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2002-07-10
2004-07-20
Short, Patricia A. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S166000, C525S179000, C525S09200D, C525S09200D
Reexamination Certificate
active
06765062
ABSTRACT:
The present invention relates to polymer blends with improved mechanical properties, in particular polyphenylene ether-polyamide resin blends.
Polyphenylene ethers, also called polyphenylene oxides, and abbreviated as PPE or PPO, are a widely used class of thermoplastic engineering resins characterized by excellent hydrolytic stability, dimensional stability, toughness, heat resistance and dielectric properties. However, they are deficient in certain other properties such as workability and solvent resistance. Therefore, there is a continuing search for means for modifying polyphenylene ethers to improve their deficiencies.
In order to overcome these problems polyphenylene ethers are blended with other resins such as polyesters, polyamides or olefin polymers. Blends of polyphenylene ethers with polyamides such as nylon 6,6 are of particular interest. Such blends are inherently incompatible and therefore “compatibilizing” agents are necessary to achieve the desired properties. Without compatibilizing agents molded articles made from these blends have inferior mechanical properties, such as low impact strength. There has been an extensive amount of work aimed at improving the compatibility of blends of polyphenylene ether and polyamide resins.
Attempts have been made towards grafting polyphenylene ether directly to the polyamide. For example U.S. Pat. No. 4,315,086 describes the use of a polyfunctional compound selected from the group consisting of liquid diene polymers, epoxy compounds and compounds having both unsaturation and a reactive group such as a carboxylic acid, anhydride, ester, etc. for this purpose. The epoxy compounds are well known epoxy resins and the like. U.S. Pat. Nos. 4,873,286 and 5,000,897 disclose the use of aliphatic polycarboxylic acids or derivatives for grafting or partially grafting polyphenylene ether with polyamide. U.S. Pat. No. 4,824,915 teaches the use of a multi-functional compound containing for example, an acid chloride group and an anhydride group for this purpose.
Other workers have focused on the formation of copolymers of polyphenylene ether and polyamide to effect their compatibility. U.S. Pat. No. 4,600,741 discloses the use of polyphenylene ether functionalized with carboxylic acid and derivatives for this purpose. U.S. Pat. No. 4,732,937 teaches the use of epoxy functionalized polyphenylene ether in order to form a copolymer with a polyester or polyamide.
U.S. Pat. Nos. 5,041,504, 5,096,979 and 5,100,961 and EP 347,539 disclose the use of epoxytriazine-capped polyphenylene ether to form copolymers with polyamides for the purposes of forming compatible blends of the two polymers.
U.S. Pat. No. 5,231,146 teaches blends of polyphenylene ether and block polyetheramides with good mechanical properties with the incorporation of a polyepoxide. Preferred polyepoxides are triglycidyl functionalized triazine derivatives. Also mentioned are copolymers of glycidyl acrylate and glycidyl methacrylate with polyacrylates, polyacrylonitrile and polystyrene. DE3837647 teaches compatibilization of polyphenylene ether-polyamide blends with the use of glycidyl triazine derivatives.
U.S. Pat. No. 4,659,763 discloses the use of quinone compounds as compatibilizing agents for blends of polyphenylene ether and polyamide.
Chiang and Chang, in the
Journal of Applied Polymer Science,
61(13), 1996, 2411-2421, discusses compatibilizing blends of polyphenylene oxide and polyamide-6 with styrene-glycidyl methacrylate copolymers. The same workers, in the
Journal of Polymer Science: Part B: Polymer Physics,
36(11), 1998, 1805-1819, disclose that a tetrafunctional epoxy monomer, N,N,N′N′-tetraglycidyl-4,4′-diaminodiphenyl methane, is an efficient compatibilizer for polyphenylene ether-polyamide-6 blends.
U.S. Pat. No. 5,141,984 discloses compatibilizing blends of polyamide resins with polyphenylene ether or polycarbonate resins with a mixture of an epoxy group-containing olefin copolymer and a vinyl polymer or copolymer.
Dedecker and Groeninckx, in
Pure Appl. Chem.
70(6), 1998, 1289-1293, teaches compatibilization of polystyrene or polyphenylene oxide with polyamide-6 with the use of a maleic anhydride-styrene copolymer. The anhydride groups of the copolymer react with the amino end groups of polyamide-6 and the copolymer is miscible with polystyrene or polyphenylene oxide, giving rise to the formation of a graft copolymer at the interface.
Kim and Jo, in
Polymer Engineering and Science,
35(8), 1995, 648-657, teach that a partially hydrolyzed styrene/t-butyl acrylate diblock copolymer performs as a compatibilizer for polyphenylene ether-polyamide-6 blends. Presumably, the amine end groups of the polyamide react with the carboxyl groups of the partially hydrolyzed diblock copolymer.
DE 3644208 discloses compatibilizing blends of polyphenylene ether-polyamide resins with a polyphenylene ether containing epoxy groups and a styrene resin. JP2245063 teaches polyphenylene ether-polyamide blends which exhibits a good balance of overall properties by incorporating a copolymer obtained from styrene, an epoxy-containing monomer and another monomer. DE3924237 discloses compatibilizing thermoplastic resins containing polar residues with polyphenylene ether by employing styrene resin with epoxy residues and styrene without epoxy groups.
EP 747440 discloses the compatibilization of polyphenylene ether-polyamide blends while maintaining good impact strength with a known compatibilizing compound and in the presence of a known impact modifying agent. Among the compatibilizers are epoxy compounds, and among the impact modifying agents are AB block copolymers such as styrene-butadiene or styrene-isoprene.
Kobatake, et al., in
Macromolecules,
31(11), 1998, 3735-3739, discloses an epoxy-functionalized nitroxyl compound. The epoxy group is used as a terminator for polybutadiene prepared by anionic polymerization. The nitroxy-functionalized polybutadiene is used as a macroinitiator in the formation of styrene-butadiene block copolymers.
U.S. Pat. No. 4,581,429, to Solomon et al., issued Apr. 8, 1986, discloses a free radical polymerization process which controls the growth of polymer chains to produce short chain or oligomeric homopolymers and copolymers, including block and graft copolymers. The process employs an initiator having the formula (in part) R′R″N—O—X, where X is a free radical species capable of polymerizing unsaturated monomers. Specifically mentioned R′R″N—O&Circlesolid; radical groups are derived from tetraethylisoindoline, tetrapropylisoindoline, tetramethylpiperidine, tetramethylpyrrolidine or di-t-butylamine.
U.S. Pat. No. 5,721,320 and WO 97/36944 disclose the preparation of rubber-reinforced polymers by polymerizing a vinyl aromatic monomer in the presence of a diene rubber having at least one stable free radical group, under polymerization conditions such that a vinyl aromatic-diene block and/or graft copolymer rubber is formed. Examples of stable free radical groups given are nitroxyl groups. U.S. Pat. No. 5,891,971 teaches the preparation of polymers with narrow polydispersity using alkoxyamine initiators. U.S. Pat. Nos. 5,627,248 and 5,677,388 disclose the free-radical polymerization of vinyl aromatic monomers using a difunctional nitroxyl initiator. Hawker in
J. Am. Chem. Soc.,
116, 1994, 11185-11186, discloses the preparation of low polydispersity polystyrene with a hindered alkoxyamine compound.
Benoit, et al., in
J. Am. Chem. Soc.,
121(16), 1999, 3904-3920, discloses the polymerization of styrene with molecular weight and polydispersity control using a variety of alkoxyamine initiators.
Surprisingly, it has been found that certain oligomers, polymers, cooligomers or copolymers (block or random) of narrow molecular weight distribution, and whose polymerization is initiated with glycidyl-functionalized nitroxyl derivatives, are especially effective at forming copolymers with polyamides under blending conditions; these copolymers in turn are especially effective as compatibilizers for the polyphenylene ether-po
Botkin James
Chin Hui
Fuso Francesco
Wunderlich Wiebke
Ciba Specialty Chemicals Corporation
Short Patricia A.
Stevenson Tyler A.
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