Abstract: A loose tube for an optical fiber comprising a polybutylene terephthalate. The polybutylene terephthalate has a terminal carboxyl group concentration of 10 eq./10.sup.6 g.multidot.polymer or less and an intrinsic viscosity ?.eta.!, measured at 25.degree. C. in orthochlorophenol, of 0.9 to 1.4 dl/g.

Abstract: A polyester resin composition having excellent molding mobility and crystallizing property, comprises (A) at least one thermoplastic polyester resin selected from polyethylene terephthalate resins and polybutylene terephthalate resins; (B) a polycaprolactone having a number average molecular weight of from 200 to 2,000 in an amount of 0.1 to 30 parts by weight per 100 parts by weight of the polyester resin, in which polycaprolactone molecules, at least 50% of the terminal radicals thereof, are modified to be non-reactive, (C) 0.01 to 10 parts by weight of a crystal nucleating agent per 100 parts of the polyester resin, and optionally, (D) at least one additive selected from fillers and specific phosphorous compounds which may be in combination with a specific epoxy compound, the polyester resin composition being useful for producing a molded product having an excellent dimensional stability and mechanical strength.

Abstract: A glass fiber-reinforced thermoplastic polyester composition composed of(A) 100 parts by weight of a polyethylene terephthalate resin having an intrinsic viscosity, measured at 35.degree. C. in ortho-chlorophenol, of from 0.4 to 0.9 and comprising at least 80 mole %, based on the total acid component, of terephthalic acid or an ester-forming derivative thereof and at least 80 mole %, based on the total polyol component, of ethylene glycol or an ester-forming derivative thereof.(B) 5 to 200 parts by weight of glass fibers having an average length of at least 0.2 mm,(C) 0.05 to 3 parts by weight of a partially esterified montan wax acid having a neutralization value (NV) and a saponification value (SV) which are in the following relation50.ltoreq.NV.ltoreq.110 (1)100.ltoreq.SV.ltoreq.180 (2)10.ltoreq.(SV-NV).ltoreq.100 (3)and(D) at least one component selected from the group consisting of(D.sub.1) 0.01 to 3 parts by weight of a sodium or potassium salt of a monocarboxylic acid having 2 to 28 carbon atoms and(D.

Abstract: A flame-retardant resin composition comprising (A) at least one polymer resin selected from the group consisting of thermoplastic polyesters and thermoplastic polycarbonates and, per 100 parts by weight of the polymer resin, (B) 0.1 to 30 parts by weight, as the weight of the halogen element, of an organic halogen compound, and (C) 0.1 to 20 parts by weight, as the weight of the antimony element, of antimony trioxide treated with an alkoxysilane compound. The composition may further comprise up to 30 parts by weight of an organic acid ester compoundf and/or up to 200 parts by weight of a filler, per 100 parts by weight of the polymer resin.

Abstract: A polyethylene terephthalate resin composition capable of providing a molded article of a high crystallinity and an excellent dimensional stability and thermal resistance consists essentially of a polyethylene terephthalate resin having an intrinsic viscosity of 0.35 to 0.9 and, per 100 parts by weight of the polyethylene terephthalate resin, 5 to 200 parts by weight of an inorganic filler, 0.01 to 20 parts by weight of dimethyl or diethyl terephthalate and 0.01 to 5 parts by weight of a salt of a carboxylic acid with a metal of Group I or II in the periodic table or 0.1 to 10 parts by weight of an ionic copolymer of an .alpha.-olefin with a salt of an .alpha.,.beta.-unsaturated carboxylic acid and containing an ion of a metal of Group I or II in the periodic table.