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
2000-03-31
2003-04-22
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...
C525S132000, C525S146000, C525S165000, C525S176000, C525S178000, C525S180000, C525S151000, C525S153000, C525S182000, C525S183000, C525S185000, C525S189000
Reexamination Certificate
active
06552127
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a thermoplastic resin composition which comprises a specific fluorine-containing polymer having a functional group and a thermoplastic resin having a crystalline melting point or glass transition temperature of not less than 150° C., and has improved mechanical and chemical properties.
BACKGROUND ARTS
Heat resisting crystalline thermoplastic resins (having a crystalline melting point of not less than 150° C.) such as polyacetals, polyamides, aromatic polyesters, polyarylene sulfides, polyketones, polyether ketones, polyamide imides and polyether nitrites are excellent in mechanical properties and moreover moldability, and therefore are used for functional parts for automobiles, industrial machineries, office automation equipments, and electrical and electronic equipments. Meanwhile there is a market demand for higher chemical resistance, sliding properties and the like, and particularly impact resistance is desired to be enhanced because those resins are generally brittle. Also, heat resisting amorphous thermoplastic resins (having a glass transition temperature of hot less than 150° C.) such as polycarbonates, polyphenylene ethers, polyalylates, polysulphones, polyether sulphones, and polyetherimides are widely used for making the best use of transparency, dimensional stability, impact resistance, and the like, but generally there are problems with chemical resistance, solvent resistance and moldability.
Fluorine-containing resins such as polytetra-fluoroethylene (PTFE), tetrafluoroethylene/perfluoro-alkyl vinyl ether copolymer (PFA), tetrafluoroethylene/hexafluoropropylene copolymer (FEP), polyvinylidene fluoride (PVDF) and ethylene/tetrafluoroethylene copolymer (ETFE) are excellent in thermal resistance, chemical resistance, solvent resistance, weather resistance, sliding properties, pliability, electrical properties and the like, and are widely used for automobiles, industrial machineries, office automation equipments, electrical and electronic equipments, and the like. However, there are many cases where those resins are inferior in mechanical properties and physical thermal resistance as represented by a deflection temperature under load, as compared with heat resisting crystalline thermoplastic resins, and the uses thereof are within the limited range because the dimensional stability is inferior as compared with heat resisting amorphous thermoplastic resins.
Attempts have been actively made to obtain novel materials by combining a fluorine-containing polymer (including resinous and elastomeric form) with the aforementioned heat resisting thermoplastic resins having no fluorine to modify such resins to eliminate disadvantages of the resins, and on the contrary by combining mainly a resinous fluorine-containing polymer with the heat resisting thermoplastic resin having no fluorine to modify such polymers.
First, as an example for simply melting and blending by the use of a kneading machine, JP-A-202344/1982 discloses that a fluorine-containing elastomer commercially available is added to improve impact resistance, crack resistance and strength against thermal shock without imparing properties of polyarylene sulfides such as thermal resistance, chemical resistance, and the like. Also, JP-A-165647/1989 and JP-A-110156/1990 disclose that a polymer, that is to say, a liquid crystal polymer (aromatic polyester or the like) forming an anisotropic melt is added to decrease a coefficient of linear expansion without impairing weather resistance, chemical resistance, wear resistance and anti-soil property of a fluorine-containing polymer such as a PVDF and further to improve mechanical properties and moldability. As examples of a blend of a liquid crystal polymer and a PTFE, there are JP-B-5693/1992 and JP-A-230756/1988. JP-A-7850/1975 discloses that it is effective to blend the PVDF for improving water absorption and hygroscopicity of polyamides.
Furthermore, JP-A-23448/1985 discloses an example that a property of release from a mold is improved by blending a fluorine-containing polymer with an aromatic polysulphone composition of which shrinkage from mold dimensions has been decreased by blending fibrous reinforcements such as glass fiber and wollastonite and inorganic fillers such as talc and glass beads.
Also, attempts have been widely and generally made to improve sliding properties of various synthetic resins by blending a PTFE powder.
However, since a surface energy of a fluorine-containing polymer is small, there is a problem that such a polymer is generally short of an affinity with other materials. Therefore, when the fluorine-containing polymer and other materials are melted and blended, there occurs a phase separation. Interfacial adhesion thereof is nearly nothing substantially, and an interfacial adhesive failure occurs easily, the fluorine-containing polymer is difficult to be dispersed in other materials during blending, and an aggregation occurs. Thus it is difficult to display an effect of blending that polymer.
In order to eliminate such drawbacks and to enhance an affinity between different polymers, it is often conducted to add so-called compatibilizing agents as the third component. JP-A-218446/1987 discloses a composition prepared by blending a thermoplastic fluorine-containing elastomer to improve impact resistance of polyarylene sulfides without imparing flowability thereof, and that patent publication describes that it is more effective to add a fluoroaliphatic group-containing polymer to improve an affinity of the polymer. Also, JP-A-62853/1988 discloses a method to add, as a compatibilizing agent, a graft polymer comprising a vinyl polymer having epoxy group and a methyl methacrylate polymer or an acrylonitrile/styrene copolymer when blending polyarylene sulfides and thermoplastic resins containing a PVDF.
Also, claim 2 of the mentioned TP-A-165647/1986, JP-A-197551/1986 and JP-A-263144/1986 disclose that it is more effective to add an acrylic polymer, polyvinyl acetate and polyvinyl methyl ketone, respectively than a simple blending, in blending a PVDF and a polymer forming an anisotropic melt.
JP-A-11109/1989 discloses an example of using, as a compatibilizing agent for blending polyamides and PVDF, a block polymer comprising any one of N-vinylpyrrolidone or methyl(meta)acrylate and any one of unsaturated ethylenic monomer, polycondensated monomer or lactam.
Also, JP-A-98650/1986 and JP-A-110550/1986 disclose that when blending a polyphenylene ether and a fluorine-containing polymer like a PVDF, a copolymer comprising polystyrene and an acrylic polymer is used as a compatibilizing agent, taking advantage of an excellent compatibility of polyphenylene ether with polystyrene and PVDF with acrylic polymer.
However, in JP-A-218446/1987, an effect of an improvement in affinity property is insufficient. It may be because a fluoroaliphatic group in an compatibilizing agent is of low polymerization having carbon atoms of not less than 20. All the other publications substantially describes the examples of using compatibilizing agents having no fluorine, which are synthesized, making use of an excellent affinity between a PVDF and a carbonyl group-containing polymer such as acrylic polymer, and the fluorine-containing polymer is limited to the PVDF. In the method to improve an affinity by the use of such a compatibilizing agent, there is a problem that physical properties of the molded articles deteriorate because chemical resistance and thermal resistance of the compatibilizing agents themselves are inferior to that of a main component, i.e. the polymer.
Also, attempts have been made to improve dispersibility of a composition comprising a fluorine-containing polymer and a thermoplastic resin, by a so-called dynamic vulcanization. TP-A-185042/1991 discloses that, when blending a crosslinkable fluorine-containing elastomer and a thermoplastic polymer having a crystalline melting point or glass transition temperature of not less than 150° C., the dispersibility is enhanced and a thermoplastic elastomer can be obta
Araki Takayuki
Kumegawa Masahiro
Shimizu Tetsuo
Tsuda Nobuhiko
Yamaguchi Seitaro
Daikin Industries Ltd.
Short Patricia A.
Varndell & Varndell PLLC
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