Patent GB-1146741-A (GB)
Title: Polyester conjugate filaments
IPC: C08G63/20
Filed: 1966-07-06
Abstract: 1,146,741. Conjugate polyester filaments. TEIJIN Ltd. 6 July, 1966 [6 July, 1965; 7 July, 1965; 4 Dec., 1965], No. 30399/66. Heading B5B. Crimpable conjugate filaments are made by separately melting at least two different ethylene glycol terephthalate polyesters at least one of which is a branched polyester containing units derived from at least one branching agent having three to six ester-forming functional groups, and spinning the melted components so that the filaments are arranged eccentrically and intimately adhered to each other along essentially the whole of their length. Suitably the branching agent is a compound of general formula A-(B) n , where B is an ester-forming functional group, n is an integer of 3 to 6, and A is an organic residue. Specified branching agents include pentaerythritol, dipentaerythritol, glycerol, sorbitol, trimethylolethane, trimethylolpropane, trimethylolbutane, trimethylolhexane, 1,3,5 - tri - methylolbenzene, 1,3,5 - tripropylolbenzene, 1,3,5 - tributylol benzene, 1,2,6 - hexanetriol, 2,2,6,5 - tetramethylolcyclohexanol, hemimellitic acid, trimellitic acid, trimesic acid, prehnitic acid, mellophanic acid, pyromellitic acid, mellitic acid, and functional derivatives of these, e.g. esters with aliphatic alcohols e.g. methyl, ethyl and propyl alcohols, or the aromatic phenol esters, or 5-hydroxyisophthalic acid, 4-hydroxyisophthalic acid, 2,5-dihydroxyisophthalic acid, 2,5-dihydroxyterephthalic acid and functional derivatives of these, e.g. the esters with an aliphatic alcohol as for example methyl, ethyl and propyl alcohol or the aromatic phenol esters. Suitably the said branched polyester contains in its molecule the branching agent residue in a proportion, based on the total acid component, of mole% (where f represents the number of esterforming functional groups in the branching agent, and is an integer of 3 to 6. Suitably the said branched polyester has a reduced viscosity before spinning of 0À64 to 0À99, preferably 0À64 to 0À88 as determined in 1À2% by weight solution in orthochlorophenol at 35‹ C. Desirably, the branched polyester is further modified with at least one terminating agent having one ester-forming functional group, specified terminating agents including ortho-benzoylbenzoic acid, benzoic acid, diphenyl-4-carboxylic acid, para-benzyl-oxybenzoic acid, paraphenylbenzoic acid, para-phenoxyethoxybenzoic acid, naphthalene-2-carboxylic acid, stearic acid, paracarboxyphenylbenzene sulphonate, diphenylsulphone-4-carboxylic acid, para - phenylphenol, ortho - chloro - para - phenylphenol, and functional derivatives of these, e.g. the esters with an aliphatic alcohol as for example methyl, ethyl and propyl alcohols, or the phenol esters, in a proportion expressed by the formula where M is the mole per cent, based on the total acid component, of the terminating agent residue in the branched polyester molecule, N is the mole per cent, based on the total acid component, of the branching agent residue in the molecule of the branched polyester, and f is the number of ester-forming functional groups of the said branching agent and is an integer of 3 to 6. Thus, when pentaerythritol having 4 ester-forming functional groups is copolymerized in a proportion of 0À4 mole per cent based on the total acid component of polyester, the proportion of the monofunctional terminating agent, e.g. benzoic acid, to be used is suitably 0À4 to 2À2 mole per cent, based on the total acid component of the terminating agent. The ethylene glycol terephthalate polyester may be polyethylene terephthalate or polyethylene terephthalate modified with a third component in a proportion less than 20 mole per cent. Specified third components include adipic acid, sebacic acid, isophthalic acid, diphenylsulphonedicarboxylic acid, diphenyl dicarboxylic acid, naphthalenedicarboxylic acid and oxybenzoic acid. As the glycol, there can be used trimethylene glycol, propylene glycol, cyclohexanedimethanol and neopentene glycol. Melt-spinning of the filaments is effected to yield side-by-side or sheath core conjugate filaments, and the filaments may be drawn at a draw ratio greater than the maximum draw ratio of the branched polyester component. Drawing may be carried out in one or more stages. The crimped filaments so obtained can be heat-treated at 60‹ to 180‹ C., preferably 70‹ to 150‹ C. in a relaxed state to impart dimensional stability to the filaments. The filaments may be cut into staple lengths before or after the heat-treatment. Alternatively the conjugate filaments may be drawn to induce crimp, heat treated in a relaxed state, given mechanical crimps by e.g. a stuffing box and cut to desired lengths to obtain staple fibres having both two-dimensional mechanical crimps and three-dimensional crimps obtained by the method of the invention. Alternatively, the conjugate filaments may be drawn, twodimensional crimps imparted to them mechanically, heat treated, and cut to staple length. The so obtained staple fibres have two-dimensional mechanical crimps as well as threedimensional crimps and excellent spinnability. When woven fabrics made of such staple fibres are heat-treated, temporary, two-dimensional crimps disappear or diminish, and instead the three dimensional crimps appear in the fabrics. Examples are given.