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.

Abstract: An electrically conductive fiber having an electric resistivity of 1.times.10.sup.12 ohm/cm or less under a D.C. voltage of 1 K.V., contains copper (I) iodide which has been deposited in the inside of at least the peripheral surface layer of an electrically non-conductive fiber matrix by contacting iodine with copper (I) ions therein.

Abstract: A fire-retardant polyester composition comprising a fiber-forming linear polyester having an intrinsic viscosity of at least 0.1 and a fire retardant containing phosphorus and bromine, wherein at least 70 mole % of the polyester consists of a recurring unit of the formula ##STR1## wherein n represents an integer of 2 to 6, and the fire retardant is a copolyphosphonate composed of 1 mole of a recurring unit of the formula ##STR2## wherein Y represents an isopropylidene or sulfonyl group, and R represents a phenyl or benzyl group,and 0.25 to 10 moles of a recurring unit of the formula ##STR3## wherein R represents a phenyl or benzyl group, the proportion of the fire retardant being 1 to 20 parts by weight per 100 parts by weight of the polyester.

Abstract: New curable monomeric aromatic imidodicarboxylic acid diallyl esters, such as 4-allyloxycarbonyl-N-(allyloxycarbonylmethyl)phthalimide, 1,2-ethylene bis(4-allyloxycarbonylphthalimide), or N,N'-bis(allyloxycarbonylmethyl) pyromellitimide. When heated in the presence of a free radical initiator, these monomers give cured polymers having very superior mechanical strength, thermal stability, chemical resistance and electrical properties. If this polymerization is stopped before the reaction mixture is gelled, prepolymers can be obtained. The cured polymers are especially useful as electronics materials and engineering plastics.

Abstract: New curable monomeric aromatic imidodicarboxylic acid diallyl esters, such as 4-allyloxycarbonyl-N-(allyloxycarbonyl-methyl)phthalimide, 1,2-ethylene bis (4-allyloxycarbonylphthalimide), or N,N'-allyloxycarbonylmethyl) pyromellitimide. When heated in the presence of a free radical initiator, these monomers give cured polymers having very superior mechanical strength, thermal stability, chemical resistance and electrical properties. If this polymerization is stopped before the reaction mixture is gelled, prepolymers can be obtained. The cured polymers are especially useful as electronics materials and engineering plastics.