Abstract: A method of producing an aromatic polyester by distilling a low-boiling fraction from a polycondensation vessel containing a reaction product obtained by acetylating raw monomers of the aromatic polyester with acetic anhydride, wherein the polycondensation vessel is provided with a partial condenser, and controlling a temperature of the low-boiling fraction distilled from the partial condenser within a range from 80 to 150° C. while the amount of the low-boiling fraction distilled from the partial condenser is within a range from 50% to 90% based on a theoretical recovery amount is provided; and according to this method, adhesion of low-molecular compounds to a partial condenser in the production can be prevented and an improvement in yield of the aromatic polyester and stabilization of product quality can be accomplished.

Abstract: An aromatic polyester comprising the repeating units (A), (B), (C) and (D) represented by the following formulae in amounts of 0 to 80 mole %, 10 to 50 mole %, 5 to 50 mole % and 0 to 30 mole %, respectively, having a logarithmic viscosity of 1.0 dl/g or more and capable of being melt-molded at a temperature of 350.degree. C. or less: ##STR1## where R represents a C.sub.2 -C.sub.6 alkylene, and--O--AR--O-- (D)where Ar represents a divalent aromatic residue, and a process for producing the same. The aromatic polyesters according to the present invention combine moldability and heat resistance in a good state and have mechanical properties of sufficient practical value. An aromatic polyester according to the present invention shows optical anisotropy at a molten state.

Abstract: An aromatic polyester superior in heat resistance and melt-moldability is obtained by carrying out the polycondensation reaction withComponent A consisting of at least one compound having the formula, ##STR1## wherein R.sub.1 is hydrogen, formyl, acetyl, propionyl or benzoyl, and R.sub.2 is hydrogen, a C.sub.1 -C.sub.6 alkyl or a C.sub.6 -C.sub.18 aryl, or a mixture containing not less than 50% by mole of said compound,Component B consisting of at least one compound having any one of the formulas, ##STR2## wherein R.sub.3 is hydroxyl, a C.sub.1 -C.sub.6 alkyloxy, a C.sub.6 -C.sub.18 aryloxy or halogen, or a mixture containing not less than 50% by mole of said compound, andComponent C consisting of at least one compound having the formula,R.sub.4 O--A.sub.1 --OR.sub.4wherein A.sub.1 is a divalent aromatic residue, and R.sub.4 is hydrogen, acetyl, propionyl or benzoylin a reaction vessel at a temperature of 270.degree. C. to 380.degree. C.

Abstract: An aromatic polyester of good processability and heat resistance is prepared by charging starting materials in a reaction vessel, carrying out polycondensation reaction in the vessel until the flow temperature of the produced aromatic polyester falls in the temperature range of from 240.degree. C. to a temperature of 20.degree. C. below the reaction temperature and discharging the reaction product from the vessel in the molten state.The aromatic polyester obtained by the present invention can be used molded into various forms such as fiber, film, etc. In addition, compositions comprising this aromatic polyester and glass fibers, mica, talc, silica, potassium titanate, wollastonite, calcium carbonate, quartz, iron oxide, graphite, carbon fibers, etc. can be used in machine parts, electric and electronic parts and automobile parts because of their excellent mechanical properties, electric properties, chemical resistance and oil resistance.

Abstract: Aromatic polyester fibers having high strength and high modulus of elasticity can be obtained stably for a long period of time by melt spinning by using a screw type extruder having a screw which has a compression ratio of 2.5 to 4.0 and thereby inhibiting entrapment in the resultant molten polyester of gases present in or on prowders, granules or pellets being melted, and by back pressure of the molten polyester sending gas generated by decomposition of the molten polyester to a back portion of the extruder, and then extruding and melt spinning the molten polyester at a temperature of 280.degree. C. to 420.degree. C.

Abstract: In a process for producing an aromatic polyester fiber by heat-treating a fiber obtained by melt-spinning an aromatic polyester exhibiting anisotropy in its molten state, an aromatic polyester fiber having high strength and high modulus of elasticity can be produced with suppressed fusion between single filaments during the heat treatment by (a) subjecting the fiber obtained by melt spinning to heat treatment in an organic liquid heating medium or (b) adhering to the fiber obtained by melt spinning at least one member selected from the group consisting of suspensions having a concentration of 0.05 to 20% by weight of organic polymer powders having a melting point or a softening temperature higher than the heat treatment temperature, and suspensions having a concentration of 0.1 to 20% by weight of barium sulfate powder or barium titanate powder, and then subjecting the resulting fiber to heat treatment.

Abstract: An optical communication cable with less breakage or damage during the preparation and handling which comprises an optical fiber strand, a tension-resistant material, and a synthetic resin coating layer, the tension-resistant material being provided between the optical fiber strand and the synthetic resin coating layer and being fibers obtained by melt spinning an aromatic polyester showing an anisotropy in the molten state.

Abstract: A polyester fiber suitable for reinforcing resin can be obtained by subjecting a fiber obtained by melt-spinning a polyester which exhibits anisotropy in its molten state to(a) a treatment comprising adhering to the fiber a solution of an epoxy group-containing compound dissolved in an organic solvent which is inert to the said compound, and then drying the resulting fiber; or(b) a treatment comprising making the fiber contact with at least one member selected from the group consisting of sulfur trioxide, chlorosulfonic acid, fluorosulfonic acid, and an aqueous sulfuric acid solution having a concentration of 30 to 95% by weight.

Abstract: A method for treating fibers to obtain treated fibers suitable as a reinforcing material which comprises treating a fiber obtained from a polyester which shows anisotropy in the molten state in an aqueous solution of at least one compound selected from the group consisting of hydroxides, carbonates, bicarbonates, and organic carboxylic acid salts of lithium, sodium, potassium, magnesium and calcium at 20.degree. to 120.degree. C. for at least one minute.The above-mentioned treatment provides treated fibers suitable as a reinforcing material which exhibit an excellent adhesion to matrices to be reinforced and can give a satisfactory strength to the resulting composite material.

Abstract: A process for producing an aromatic polyester by polycondensation of either(1)(a) aromatic hydroxycarboxylic acids containing at least 50 mole % of p-hydroxybenzoic acid, and/or ester-forming derivatives of these acids,(b) an aromatic dicarboxylic acid and/or an ester-forming derivative of aromatic dicarboxylic acid, and(c) an aromatic dihydroxy compound and/or an ester-forming derivative of aromatic dihydroxy compound,wherein the (a):(b) molar ratio and the (a):(c) molar ratio are each from 1:0 to 1:4, or(2)(d) aromatic dicarboxylic acids containing at least 50 mole % of terephthalic acid, and/or ester-forming derivatives of these acids and(e) aromatic dihydroxy compounds containing at least 50 mole % of at least one of hydroquinone, substituted hydroquinone, 4,4'-dihydroxydiphenyl, and substituted 4,4'-dihydroxydiphenyl, and/or ester-forming derivatives of these dihydroxy compounds,characterized in that the polycondensation is carried out by using a liquid compound which has a higher boiling point at normal

Abstract: A method for treating fibers which comprises modifying the surface of a fiber of a polyester which shows anisotrophy in the molten state by subjecting the fiber to a low-temperature plasma irradiation, said method enabling to obtain fibers which comprise highly oriented molecules, are highly crystalline and hence exhibit a high tenacity and a high modulus of elasticity.The fibers thus obtained are suitable as a reinforcing material, exhibit an excellent adhesion to matrices to be reinforced and can give a satisfactory strength to the resulting composite material.

Abstract: In the method for producing aromatic polyesters having excellent moldability, good thermal resistance and little dependence on molding temperature and providing molded products having little anisotropy, obtained from (A) one or more compounds selected from aromatic dicarboxylic acids and their derivatives and (B) one or more compounds selected from aromatic dihydroxy compounds and their derivatives, or (A), (B) and (C) one or more compounds selected from aromatic hydroxycarboxylic acids and their derivatives, a method characterized in that polymerization is carried out in a reaction system containing, together with (A), (B) and optionally (C), a quinone compound (D) and/or a complex obtained from (B) and (D) as well as an organic carboxylic acid anhydride, or a reaction product thereof.

Abstract: In a method for producing aromatic polyesters having improved moldability by the polycondensation ofA: one or more compounds selected from the group consisting of aromatic hydroxycarboxylic acids and their functional derivatives such as acylated or esterified compounds thereof,or A withB: one or more compounds selected from the group consisting of aromatic dicarboxylic acids and their functional derivatives such as esterified compounds or acid halides thereofandC: one or more compounds selected from the group consisting of aromatic diphenols and their functional derivatives such as acylated compounds thereof,the improvement comprising adding to the reaction system, either in bulk, or gradually during polycondensationD: one or more compounds selected from the group consisting of 1,3,5-trihydroxybenzene, 3,5-dihydroxybenzoic acid, 5-hydroxyisophthalic acid and their functional derivatives such as acylated or esterified compounds thereof,whereby D is included in the reaction.

Abstract: In a process for producing an aromatic polyester fiber of high strength and high modulus of elasticity represented by the prescribed general formula, a process comprising grinding a polymer of the prescribed general formula to form ground particles having diameters of less than 3 mm and an average particle diameter of 0.5 mm or smaller; heat-treating the particles for 0.5 to 30 hr at a temperature between 100.degree. and 350.degree. C., at which temperature the particles do not fuse; melt-spinning the heat-treated particles at a temperature of 250.degree. to 450.degree. C. if the particles have a melt property such that the temperature at which the particles possess a shear rate of 51/sec (48,000 poise as melt viscosity) under a shear stress of 2.45.times.10.sup.6 dynes/cm.sup.2 is in the range of 200.degree. to 350.degree. C.; and thereafter heat-treating the resulting fiber for 0.5 to 50 hr at a temperature between 250.degree. and 450.degree. C., at which temperature the fiber does not fuse.

Abstract: A resin composition comprising:(A) a polyphenylene oxide resin or a resin composition containing polyphenylene oxide, and(B) a copolymer of an olefin and glycidyl methacrylate and/or glycidyl acrylate.The aforesaid resin composition is excellent in processability, impact resistance and oil resistance as well as adhesiveness with inorganic fillers such as glass fiber, calcium carbonate, silica, titanium oxide, etc.

Abstract: A resin composition for electrocoating which comprises(I) a reaction product (G) of an epoxy compound (E), optionally an epoxy group-modifying agent (F) and a partially esterified and/or partially amidated product (D) which is obtained by partially esterifying and/or partially amidating an adduct (A) of a conjugated diene polymer with an .alpha.,.beta.-unsaturated dicarboxylic acid or its anhydride with an alcoholic hydroxy group-containing compound (B) and/or a primary or secondary monoamine (C), respectively, and(II) a completely blocked organic polyisocyanate,said mixture of the reaction product (G) and the completely blocked organic polyisocyanate being neutralized, ora neutralized product of an adduct (H) of the reaction product (G) with a partially blocked organic polyisocyanate.The resin composition is applicable to electrocoating, particularly cathodic electrocoating, and hence, is useful for electrocoating of steel products, particularly for electrocoating of automobiles.

Abstract: A method for isolating a low molecular weight polymer from a solution of a low molecular weight polymer having a viscosity of 5 to 100,000 cps at 30.degree. C. and an inactivated catalyst in a hydrophobic organic solvent, which comprises mixing an acidic, alkaline or neutral water or a mixture of the water and a water-soluble organic solvent with the solution containing the low molecular weight polymer in the presence of an amphoteric, cationic or nonionic surfactant or a nonionic or cationic high molecular weight flocculating agent, whereby the separation of the organic layer and the aqueous layer is significantly improved.