Europaisches Patentamt 19 European Patent Office Office europeen des brevets © Publication number : 0 566 377 A1 12) EUROPEAN PATENT APPLICATION (2j) Application number : 93302882.1 © int. ci.5: C08L 71/12, C08L 77/00, C08K 3/00, C08K 5/00, (22) Date of filing : 14.04.93 C09B 29/00 (30) Priority : 14.04.92 US 868289 (72) Inventor : Nagaoka, Kenji 832-4, Shiizu Ichihara-shi, Chiba 299-01 (JP) (43) Date of publication of application : Inventor : Hagimori, Hiroshi 20.10.93 Bulletin 93/42 1353-4, Shiizu Ichihara-shi, Chiba 299-01 (JP) Inventor : Suzuki, Yasuro @ Designated Contracting States : 5-9-14, Hatazawaminami BE DE FR GB IT NL Kisarazu-shi, Chiba 292 (JP) Inventor : Sanada, Takashi 135, Iriyamazu © Applicant : SUMITOMO CHEMICAL Ichihara-shi, Chiba 299-01 (JP) COMPANY, LIMITED 5-33, Kitahama 4-chome Chuo-ku Osaka (JP) (74) Representative : Cresswell, Thomas Anthony J.A. Kemp & Co. 14 South Square Gray's Inn London WC1R 5LX (GB) @) Polyphenylene ether compositions resistant to discolouration. (57) A polymer composition having improved discoloration resistance upon exposure to light comprises a polyphenylene ether, a polyamide, and a combination of (a), an inorganic filler selected from the group consisting of titanium oxide, zinc oxide, zinc sulfide, aluminium oxide, magnesium oxide, titanium oxide coated mica, and metal particles, and (b), an organic dye or pigment which bleaches upon exposure to light, in an amount effective to improve the discoloration resistance. CO CO CO 10 LU Jouve, 18, rue Saint-Denis, 75001 PARIS EP 0 566 377 A1 The present invention relates to a novel resin composition which comprises, (A) a polymer composition comprising a polyphenylene ether, optionally a styrene resin, a polyamide, op- tionally an impact strength improving polymer, and optionally an agent to improve the compatibility of the polyphenylene ether and the polyamide (hereinafter referred to as compatibilizer) and, 5 (B) a combination of (a) at least one inorganic filler selected from the group consisting of titanium oxide, zinc oxide, zinc sul- fide, aluminum oxide, magnesium oxide, titanium oxide coated mica, and metal particles, and, (b) at least one organic dye or pigment which bleaches upon exposure to light, 10 in an amount effective to improve the discoloration resistance of the polymer composition (A). The term polyphenylene ether is well known to those skilled in the art as a family of thermoplastic materials having excellent physical properties such as dimensional stability and high glass transition temperature, and they are made by a variety of processes from the corresponding phenols. Some of the polyphenylene ethers are disclosed in the patent literature, e.g., U.S. Pat. Nos. 3,306,874, and 3,573,257 and the like. 15 Blends of a polyphenylene ether and a styrene resin are also well known in the art and are disclosed in the prior art patent literature, e.g., U.S. Pat. Nos. 3,383,435, 3,658,495 and the like. Blends of a polyphenylene ether and a polyamide have also long been well known in the art, and disclosed in numerous patent literature. U.S. Pat. No. 3,379,792, for example, teaches the processability of a polyphenylene ether can be improved by incorporating therein up to 25% by weight of a polyamide. 20 Compatibilized blends of a polyphenylene ether and a polyamide are also well known in the art and dis- closed in the prior art patent literature. U.S. Pat. No. 4,315,086 teaches the use of liquid diene polymer, epoxy compounds, and compounds having in the molecule both (a) a carbon-carbon double bond or a carbon-carbon triple bond and (b) a carboxylic acid, acid anhydride, acid amide, imide, carboxylic acid ester, amino or hydroxyl group, as compatibilizers. 25 U.S. Pat. No. 4,659,763 teaches the use of quinone compounds, U.S. Pat. No. 4,600,741 teaches the use of trimellitic anhydride acid chloride, W085/95372 teaches the use of a certain class of dicarboxylic acids such as citric acid, and W087/97281 teaches the use of vinyltrimethoxy silane, as compatibilizers. While the above mentioned polyphenylene ether/polyamide blends exhibit improved melt flow property, improved chemical re- sistance, and if compatibilized by a compatibilizer, excellent mechanical properties, they have one big draw- 30 back that they can be easily discolored upon exposure to light. Further, the discoloring can be observed even in case of fabricated articles therefrom which surface is coated by a paint coat layer depending on the thickness and color of the paint coat layer. The use of an organic dye or pigment in polymer blends for the purpose of reducing the discoloration there- of upon exposure to light are disclosed in some patent literature. Japanese Kohkoku Pat. No. 85-58258 teaches 35 the use of a dye such as Solvent Yellow 105, in polyethylene terephthalate compositions. U.S. Pat. No. 4,493,915 discloses a polymer blend comprising a polyphenylene ether, a dye selected from purple anthra- pyridone and yellow quinophtalone, and titanium oxide. The above prior arts, however, do not specifically relate to a polyphenylene ether/polyamide composition Blends of a polyphenylene ether and an inorganic filler are also well known in the art and are disclosed in the 40 prior art patent literature. U.S. Pat. No. 3,943,191 , for example, discloses a polymer blend comprising a polyphenylene ether, a poly- styrene and titanium oxide as a reinforcing agent, but does not relate to a polyphenylene ether/polyamide com- position. U.S. Pat. No. 4,167,507 discloses a polymer blend comprising a polyphenylene ether, a polystyrene and a small amount of zinc sulfide and zinc oxide, but again does not relate to a polyphenylene ether/polyamide 45 composition. U.S. Pat. No. 4,31 8,636 discloses a polymer blend comprising a polyphenylene ether, a polystyr- ene and aluminum flake as an agent to give electromagnetic interference shielding characteristic thereto, but does not relate to a polyphenylene ether/polyamide composition. It has now been discovered that the discoloration resistance of a polyphenylene ether/polyamide compo- sition can be improved by incorporating a combination of (a) at least one inorganic filler selected from the group so consisting of titanium oxide, zinc oxiside, zinc sulfide, magnesium oxide, aluminum oxide, titanium oxide coated mica and metal particles, and (b) at least one organic dye or pigment which bleaches upon exposure to light. Summary of the invention 55 According to the present invention a polyphenylene ether/polyamide composition having improved resis- tance to discoloration upon exposure to light can be prepared by incorporating therein a combination of (a) at least one inorganic filler selected from the group consisting of titanium oxide, zinc oxide, zinc sulfide, magne- sium oxide, aluminum oxide, titanium oxide coated mica, and metal particles, and (b) at least one organic dye 2 EP 0 566 377 A1 or pigment which bleaches upon exposure to light, in an amount effective to improve the discloration resistance of the polyphenylene ether/polyamide composition. In general the composition of the present invention can be prepared from 5 (A) a composition comprising, (a) at least one polyphenylene ether and, (b) optionally a styrene resin and, (c) at least one polyamide and, (d) optionally one or more impact strength improving polymers and, 10 (e) optionally one or more agents to improve the compatibility of the polyphenylene ether and the poly- amide and, (B) a combination of (a) at least one inorganic filler selected from the group consisting of titanium oxide, zinc oxide, zinc sul- fide, aluminum oxide, magnesium oxide, titanium oxide coated mica and metal particles and, 15 (b) at least one organic dye or pigment which bleaches upon exposure to light in an amount effective to improve the discoloration resistance of the polymer composition (A). In the preparation of the polymer composition according to the present invention, the ratio between a poly- phenylene ether and a polyamide is preferably from about 5% to about 95%, more preferably from about 1 0% to about 70%, most preferably from about 20% to about 60% by weight of the polyphenylene ether and sup- 20 plementally the balance being a polyamide. When employed, a styrene resin may be incorporated substituting a portion of the polyphenylene ether. When employed, one or more impact strength improving polymers can be used in an amount of from about 2 to 50 parts, preferably from about 5 to about 30 parts by weight based on 100 parts by weight of the polyphenylene ether and the polyamide. When employed, one or more compatibilizers can be used in an amount of from about 0.01 to 30 parts, 25 preferably from about 0.1 to 5 parts, furthermore preferably 0.1 to 1 parts by weight based on 100 parts by weight of the polyphenylene ether and the polyamide. The amount of an inorganic filler to be incorporated in the polymer composition according to the present invention varies depending on the particle size and the iden- tity of the filler. In general, a filler having smaller particle size gives better discoloration resistance. When employed, a metal particle is preferably used in an amount of from about 1 to about 10 parts, more 30 preferably from about 2 parts to about 5 parts by weight based on 100 parts by weight of the polymer compo- sition (A). When employed, the inorganic fillers other than metal particles are used in an amount of preferably from about 3 to about 20 parts, more preferably from about 5 to 15 parts by weight based on 100 parts by weight of the polymer composition (A). 35 The preferred mean particle size of the inorganic fillers other than metal particles is about 1 micron or lower, and more preferred particle size is about 0.5 micron or lower.