Abstract: An aromatic polyester filament yarn dyed in a chromatic color and exhibiting a bright and clear shade, wherein the filaments of the yarn are composed of an aromatic polyester polymer copolymerized with an aliphatic dicarboxylic acid component and/or an aliphatic diol component and having a glass transition temperature (Tg) of not higher than 65° C., the yarn appears as a whole to have been dyed visually uniformly despite that uneven build-up of dye exists in the individual filaments in the longitudinal direction, and the yarn has a chromaticness C* of at least 36 expressed in the L*a*b* color specification system when dyed with an aqueous dispersion of 1% o.w.f. of a disperse dye based on C.I. Disperse Blue 56.

Abstract: This invention provides a method for filling a hollow portion of a hollow fiber with a gel without requiring special equipment such as pressure resistant facilities and enabling an industrial mass production, which comprises immersing said hollow fiber on the surface of which pores are diffusely distributed to communicate to said hollow portion in a gelable liquid, leaving said hollow fiber at room temperature so that said gelable liquid may be absorbed through said pores into the hollow portion, and finally causing thus absorbed gelable liquid gelled.

Abstract: An aromatic polyester shaped article, for example, a fiber, a film or a sheet, having excellent hydrophilic characteristics and a durable antistatic property, sweat-absorbing property and soil-releasing property, is prepared from an aromatic polyester composition comprising (a) 100 parts by weight of an aromatic polyester resin, (b) 0.2 to 30 parts by weight a water-insoluble polyoxyethylene type polyether represented by the formula (I): ##STR1## wherein Z is a residue of an organic compound having 1 to 6 active hydrogen atoms and a molecular weight of 300 or less, R.sup.1 is an unsubstituted or substituted alkylene group having at least 6 carbon atoms, R.sup.2 is H, a monovalent hydrocarbon group having 1 to 40 carbon atoms, or a monovalent acyl group having 2 to 40 carbon atoms, k is 1 to 6, l satisfies the relationship: k x l.gtoreq.70 and m is 1 or more, and having a number average molecular weight of 5000 to 16000, said R.sup.1, R.sup.

Abstract: An aromatic polyester shaped article, for example, a fiber, a film or a sheet, having excellent hydrophilic characteristics and a durable antistatic property, sweat-absorbing property and soil-releasing property, is prepared from an aromatic polyester composition comprising (a) 100 parts by weight of an aromatic polyester resin, (b) 0.2 to 30 parts by weight a water-insoluble polyoxyethylene type polyether represented by the formula (I):Z--[(CH.sub.2 CH.sub.2 O).sub.l -(R.sup.1 O).sub.m -R.sup.2 ]k (I)wherein Z is a residue of an organic compound having 1 to 6 active hydrogen atoms and a molecular weight of 300 or less, R.sup.1 is an unsubstituted or substituted alkylene group having at least 6 carbon atoms, R.sup.2 is H, a monovalent hydrocarbon group having 1 to 40 carbon atoms, or a monovalent acyl group having 2 to 40 carbon atoms, k is 1 to 6, l satisfies the relationship: k.times.l.gtoreq.70 and m is 1 or more, and having a number average molecular weight of 5000 to 16000, said R.sup.1, R.sup.

Abstract: An improved copolyester fiber capable of being dyed with cationic dyes and having an excellent brightness, heat resistance and a satisfactory mechanical strength comprises a copolyester resin comprising a polymerization product of at least one aromatic dicarboxylic acid compound, at least one alkylene diol compound and at least one quaternary phosphonium organic sulfonate of the formula (I): ##STR1## wherein A=an aromatic or aliphatic radical, X.sup.1 =H or an ester-forming organic radical, X.sup.2 =an ester-forming organic radical, R.sup.1, R.sup.2, R.sup.3 and R.sup.4 =an alkyl or aryl radical, n=1 or more, and having an [.eta.].sub.f of 0.5 or more, the copolyester fiber having a silk factor of 25 or more and exhibiting the number of scission of backbone chains of the copolyester molecules of 140.times.10.sup.23 or less per 10.sup.6 g of fiber when wet heat-treated in a solution of 0.4 g/l of acetic acid in distilled water at 130.degree. for 60 minutes.

Abstract: A polyester fiber having a superior stainproof property comprises at least one fiber-forming polyester copolymer comprising a backbone polyester polymer and at least one type of terminal substituent which blocks at least some of the terminals of the molecules of the backbone polyester polymer and which substituent consists of a polyoxyalkyleneglycol monoether group of the formula (I):R.sup.1 -O--R.sup.2 -O.sub.n (I)wherein R.sup.1 is a monovalent organic radical free from active hydrogen atom, R.sup.2 is an alkylene radical, and n is an integer of 2 or more.

Abstract: 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.

Abstract: A polyester composition with an excellent high-speed melt-spinning property, comprising(A) 100 parts by weight of a matrix polyester resin comprising at least 80 molar % of an ethylene terephthalate recurring unit, and(B) 0.2 to 7 parts by weight of a dispersoid dispersed in the matrix,the dispersoid being such that, when it is contained in a predetermined amount (w) in a typical matrix polyester resin consisting of a polyethylene terephthalate having an intrinsic viscosity of 0.640, the resultant exemplary polyester composition satisfies the relationship (I): ##EQU1## wherein: .gamma..sub.1 =shearing rate of 0.01 sec.sup.-1 ; .gamma..sub.2 =shearing rate of 5.0 sec.sup.-1 ; .eta..gamma..sub.1 (w)=melt viscosity (poise=1/10 N.multidot.sec.multidot.m.sup.-2) of the exemplary polyester composition at .gamma..sub.1 ; .eta..gamma..sub.1 (0)=melt viscosity of matrix polyester resin at .gamma..sub.1 ; .eta..gamma..sub.2 (w)=melt viscosity of the exemplary polyester composition at .gamma..sub.2 ; and .eta..gamma..

Abstract: Hollow water-absorbing polyester filaments each having a number of fine caves which are evenly distributed in at least a portion of the filament and through which the hollow is connected to the outside of the filament, are produced (1) by preparing hollow filaments from a blend of a principal polyester component and a cave-forming agent consisting of at least one member selected from:(i) copolyesters containing an additional divalent organic sulfonic acid compound moiety of the formula (II): ##STR1## wherein Z is a trivalent aromatic or aliphatic hydrocarbon radical, M.sup.1 is H or metal atom, R.sup.1 is an ester-forming organic radical and R.sup.2 is an H atom or ester-forming organic radical;(ii) phosphorus compounds of the formula (III): ##STR2## wherein R.sup.3 is a monovalent organic radical, X is --OR.sup.4, wherein R.sup.4 is an H atom or a monovalent organic radical, --OM.sup.3, wherein M.sup.3 is a metal atom, or a monovalent organic radical, M.sup.

Abstract: A dyed polyester fiber composite structure having an enhanced brilliance and/or color depth, comprises (A) a dyed porous polyester fiber which has been produced (1) by preparing a polyester resin from a dicarboxylic acid component and a glycol component in the presence of a pore-forming agent containing 0.3 to 3 molar % of at least one phosphorus compound based on the molar amount of the dicarboxylic acid component, (2) by converting the polyester resin to a polyester fiber in which fine particles of the pore-forming agent are dispersed, by treating the polyester fiber with an aqueous alkali solution so that at least 2% of the weight of the fiber is removed and a number of fine pores are formed in the fiber and (4) by dyeing the porous polyester fiber; and (B) a coating layer on the peripheral surface of the dyed porous polyester fiber, comprising a polymeric material having a smaller refractive index than that of the porous polyester fiber.

Abstract: Hollow water-absorbing polyester filaments each having a number of fine caves which are evenly distributed in at least a portion of the filament and through which the hollow is connected to the outside of the filament, are produced (1) by prepared hollow filaments from a blend of a principal polyester component and a cave-forming agent consisting of at least one member selected from:(i) copolyesters containing an additional divalent organic sulfonic acid compound moiety of the formula (II): ##STR1## wherein Z is a trivalent aromatic or aliphatic hydrocarbon radical, M.sup.1 is H or metal atom, R.sup.1 is an ester-forming organic radical and R.sup.2 is an H atom or ester-forming organic radical;(ii) phosphorus compounds of the formula (III): ##STR2## wherein R.sup.3 is a monovalent organic radical, X is --OR.sup.4, wherein R.sup.4 is an H atom or a monovalent organic radical, --OM.sup.3, wherein M.sup.3 is a metal atom, or a monovalent organic radical, M.sup.

Abstract: Hollow water-absorbing polyester filaments each having a number of fine caves which are evenly distributed in at least a portion of the filament and through which the hollow is connected to the outside of the filament, are produced (1) by preparing hollow filaments from a blend of a principal polyester component and a cave-forming agent consisting of at least one member selected from:(i) copolyesters containing an additional divalent organic sulfonic acid compound moiety of the formula (II): ##STR1## wherein Z is a trivalent aromatic or aliphatic hydrocarbon radical, M.sup.1 is H or metal atom, R.sup.1 is an ester-forming organic radical and R.sup.2 is an H atom or ester-forming organic radical;(ii) phosphorus compounds of the formula (III): ##STR2## wherein R.sup.3 is a monovalent organic radical, X is --OR.sup.4, wherein R.sup.4 is an H atom or a monovalent organic radical, --OM.sup.3, wherein M.sup.3 is a metal atom, or a monovalent organic radical, M.sup.

Abstract: Hollow water-absorbing polyester filaments, each having fine pores evenly distributed throughout the filament and extending approximately in parallel to the filament axis, are produced by melt-spinning a blend of a polyester and a pore-forming agent consisting of at least one sulfonate compound of the formula:R'SO.sub.3 M'wherein R' is an alkyl radical having 3 to 30 carbon atoms or an aryl or alkylaryl radical having 7 to 40 carbon atoms and M' is an alkali or alkaline earth metal, and by removing at least a portion of the sulfonate compound from the hollow filaments by using an alkali aqueous solution so as to cause a number of fine pores to be formed in the hollow filaments and to cause each hollow to be connected to the outside of the filament through the fine pores.