Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Patent
1982-08-06
1986-03-25
Kight, John
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
524101, 524291, 524401, 524408, 524409, 524494, C08K 534, C08K 511, C08K 322
Patent
active
045784086
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a photodiscoloration-resistant polyester resin composition.
More particularly, the present invention relates to a polyester resin composition which is excellent in flame retardance and photodiscoloration resistance and which can provide a molded article free of bleeding of a flame retardant on the surface.
BACKGROUND ART
Thermoplastic polyester resins, especially polyethylene terephthalate and polybutylene terephthalate, are used in various fields with or without reinforcement with glass fibers or the like, and serve as engineering plastics having excellent mechanical and electrical properties and also having good chemical resistance and heat resistance. However, they are defective in that they are combustible. Therefore, from the industrial viewpoint, it is important to render these thermoplastic resins flame-retardant.
There are known various methods for rendering thermoplastic polyester resins flame-retardant. Ordinarily, a flame retardant capable of imparting a flame retardance is incorporated alone or in combination with a flame retardant assistant to obtain a flame-retarding effect. However, when known flame retardants are incorporated into polyester resins for exterior articles, significant discoloration is caused in the resulting exterior articles by the action of solar rays and their colors become incongruous with colors of other exterior articles, with the result that the value of the exterior articles is reduced. In case of articles other than such exterior articles, if molded articles of thermoplastic resins containing conventional flame retardants are used in a high-temperature atmosphere, the flame retardants bleed out on the surfaces of the molded articles to cause an undesirable whitening phenomenon. Accordingly, these flame retardants are not suitable for thermoplastic polyester resins for use in production of exterior articles and electrical parts to which a high voltage is applied.
DISCLOSURE OF THE INVENTION
We have made researches on various flame retardants with a view to eliminating the foregoing defects and, as a result, found that a brominated organic compound having a triazine ring is an effective flame retardant. We have now completed the present invention based on this finding. It also was found that when at least one member selected from ordinary ultraviolet stabilizers of the benzophenone, benzotriazole and phenyl salicylate types is incorporated into a polyester composition comprising the flame retardant of the present invention, the photodiscoloration resistance is improved. Furthermore, it was found when at least one member selected from ordinary antioxidants of the hindered phenol, amine and phosphite types is incorporated into a polyester composition comprising the above-mentioned flame retardant and ultraviolet stabilizer, the improvement of the photodiscoloration resistance is still enhanced.
By the term "polyester resin" used in the instant specification is meant a polymer of a glycol ester of terephthalic acid, isophthalic acid or an alkyl ester thereof. A blend of two or more of such polymers may be used in the present invention.
As the especially preferred polyester resin, there can be mentioned polybutylene terephthalate and a mixture of polybutylene terephthalate and polyethylene terephthalate.
At least one member selected from brominated cyanuric acid esters having a triazine ring, which are represented by the following general formula, is used as the flame retardant in the present invention: ##STR1## wherein n stands for the degree of polymerization, R stands for H, R.sub.1 or R.sub.2 with the proviso that if R is present on the terminal end of the polymer chain, R.sub.1 or R.sub.2 is terminated with H, OH, a halogen such as chlorine or bromine or R.sub.2 (having H, OH or a halogen as the terminal group), R.sub.1 stands for a group of the following formula: ##STR2## in which each of a, b, c and d is an integer indicating the number of substituents and these integers, a, b, c and d satisfy the relationship o
REFERENCES:
patent: 3950306 (1976-04-01), Pews et al.
patent: 3959219 (1976-05-01), Aoyama et al.
patent: 3962174 (1976-06-01), Berardinelli
patent: 3980616 (1976-09-01), Kimura et al.
patent: 4039538 (1977-08-01), Klenkenberg et al.
patent: 4333869 (1982-06-01), Marciandi et al.
Tinuvin 328 Ultraviolet Light Absorber for Plastic and Coatings, ASTM D 2244-79, pp. 43-51.
Amnon et al., Chemical Abstracts, (75) 152887f, p. 56, 1971.
Research Disclosure, No. 15143-Nov. 1976, Industrial Opportunities Ltd.-HOMEWELL, HAVANT/Hampshire (GB), "Polymeric Flame Retardant Additives", pp. 53, 54.
Ikenaga Yukio
Matsuno Osamu
Matsuoka Masatoshi
Kight John
Morgan Kriellion
Polyplastics Co. Ltd.
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