Sumitomo Chemical Company, Limited

Japan Exlan Company Limited

Hiroaki Sugimoto

Kazuo Hayatsu

Katsuji Ueno

Toshiyuki Kobashi

Yoshitaka Ohbe

Seiji Takao

Yasuyuki Kato

Makoto Hanabata

Junichi Kimura

Masahiro Fujiwara

Shozaburo Imai

Masatsune Kondo

Haruo Suzuki

Atsukazu Iwata

Zyunso Saito

Jun Takagi

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

Aromatic polyester and a process for producing the same

An aromatic polyester superior in heat resistance and melt-moldability is obtained by carrying out the polycondensation reaction with Component 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, and Component C consisting of at least one compound having the formula,

Process for producing aromatic polyesters

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.

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.

Process for melt spinning aromatic polyester

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.

Process for producing aromatic polyester fiber

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.

Optical communication cable

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

Method of treating fiber

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.

Method for treating polyester fibers having melt anistrophy

An aromatic polyester showing anisotropy in the molten state is melt spun stably for a long period of time by controlling an extrusion pressure at a nozzle portion to 3 kg/cm.sup.2 G or higher and an atmospheric temperature T.sub.N at a nozzle outlet to a degree satisfying the following formula: (T.sub.F -100).ltoreq.T.sub.N .ltoreq.T.sub.F, wherein T.sub.F is a flowing temperature of the aromatic polyester, and preferably controlling the pressure of a polymer melt at a tip outlet of an extruder to 15 kg/cm.sup.2 G or higher, whereby a highly orientated fiber of fine denier is obtained.

Melt spinning process of aromatic polyester

A process for producing an aromatic polyester by polycondensation of either

Process for producing aromatic polyester

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.

Method for treating fibers

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.

Method for producing aromatic polyesters

In a method for producing aromatic polyesters having improved moldability by the polycondensation of

Method for producing branched aromatic polyesters

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.

Process for producing an aromatic polyester fiber

A process for producing an aromatic polyester composition, which is characterized in that in producing an aromatic polyester represented by the general formula A, ##STR1## (wherein X is an alkylene group having 1 to 4 carbon atoms, --O--, --SO.sub.2 --, --S--, or --CO--; m and n are each 0 or 1; the ratio of d to e is in the range of from 1:1 to 10:1; the ratio of e to f is in the range of from 9:10 to 10:9; and the substituents attached to the benzene ring are in para or meta position to one another), the polymerization is carried out by the method of bulk polymerization, using substantially no solvent, and in the presence of at least one polymer selected from the group consisting of polyalkylene terephthalates, polyphenylene sulfides, aromatic polysulfones, and aromatic polyesters represented by the general formula B, ##STR2## wherein (p+q) is in the range of from 10 to 100 and p/(p+q).gtoreq.0.8.

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Takatsuki, Japan

Hiroaki Sugimoto