Teijin Limited

Tadashi Konishi

Togi Suzuki

Shinji Ohwaki

Noritsugu Saiki

Setsuo Yamada

Kohichi Iohara

Yorihiko Omoto

Masashi Kuno

Shigehiro Ichihara

Katsuo Kunugi

Hisanori Murai

A fiber composed of a polyester having at least a part of terminals blocked with the residue of at least one specific metal sulfonate compound, where the amount of the blocked terminals is 1.3 to 4.0 mol % based on the dicarboxylic acid component of the polyester and the alkali dissolution speed constant is 3.3.times.10.sup.-9 to 6.5.times.10.sup.-9 cm/sec. This polyester has a good dyeability with a cationic dye and is excellent in the heat resistance and alkali resistance. The polyester fiber can be spun at a high speed or super high speed and can be false-twisted at a high temperature.

Modified polyester fiber and process for preparation thereof

A process for preparing a high-molecular weight polyester comprising additionally polymerizing a polyester obtained from a dicarboxylic acid component composed mainly of an aromatic dicarboxylic acid and/or an ester-forming derivative thereof and a glycol component composed mainly of ethylene glycol and/or an ester-forming derivative thereof and having an intrinsic viscosity of at least 0.8, at a temperature above the melting point of the polyester and under a reduced pressure, in the presence of a compound (A) successively generating a substance which is gaseous under the polymerization conditions and does not substantially reduce the molecular weight of the polyester, to form a polyester having an intrinsic viscosity of at least 1.0.

Process for preparation of high-molecular weight polyester

A polyester composition with an excellent high-speed melt-spinning property, comprising

Polyester composition

A process for preparing a polyester which comprises reacting a di-lower alkyl ester of a difunctional carboxylic acid at least 90 mole% of which consists of terephthalic acid with a polymethylene glycol containing 2 to 10 carbon atoms at least 90 mole% of which consists of ethylene glycol in the presence of an ester-interchange reaction catalyst to form an ester-interchange reaction product, and then polycondensing it in the presence of a polycondensation catalyst, wherein a substantially uniform solution in ethylene glycol of (A) 20 to 150 millimole%, based on said di-lower alkyl ester of the difunctional carboxylic acid, of calcium acetate and (B) 2 to 25 millimole%, based on said di-lower alkyl ester, of cobalt acetate is used as the ester-interchange reaction catalyst.

Process for preparing polyesters

Scale formation in a continuous ester-interchange reaction for the production of polyesters, is prevented by subjecting a dialkyl ester of a difunctional carboxylic acid at least 80 mole% of which consists of terephthalic acid and at least one glycol to a continuous ester-interchange reaction catalyst in the presence of a catalytic amount of an ester-interchange reaction catalyst composed of a manganese compound and a lithium compound, the amount of said ester-interchange reaction catalyst being the one which meets the following expressions (i) and (ii)

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Matsuyama, Japan

Tadashi Konishi