Patent GB-911791-A (GB)
Title: Process for modifying the properties of fibres and foils of aromatic polyesters
IPC: D06P1/649
Filed: 1959-03-13
Abstract: The properties of fibres and foils made from linear aromatic polyesters, e.g. polyethylene terephthalate, are modified by treating them for a period within the range of 10-4 seconds to 5 seconds at a temperature above 200 DEG C., e.g. 200 DEG -350 DEG C., with a chemical substance which acts as a swelling agent for the polyester under the conditions of the process but does not react chemically therewith, either as such or in the presence of an organic solvent. The swelling agent may be an ester, ether, ketone or nitrile, e.g. the dimethyl and diethyl esters of sebacic, azeloic and suberic acids, benzophenone, adipic acid dinitrile, ethyl-b -naphthol ether and diphenyl ether.  The fibres or foils may be passed at a draw-off speed of 10-2,000 metres per minute with a path of immersion of 0,5-10 cm. through a bath containing the swelling agent at the required temperature. Excess swelling agent may then be removed by passing the fibres and foils over a surface heated to 200 DEG -350 DEG C., by passing them through a current of air at a corresponding temperature, by subjecting them to infra-red radiations or by washing, and they may then be chilled in a bath of cold water. Alternatively the fibres or foils may be treated with the swelling agent and heated to the required temperature or the swelling agent may be applied in the gaseous state.  The stiffness and pulling resistance of fibres may be modified by regulating the tension in the fibres during treatment with the swelling agent.  Unfixed polyester continuous filaments which are allowed to shrink during the treatment with the swelling agent may be treated.  Specifications 609,943, 609,944, 609,945, 609,946, 609,947, 697,983, 697,984, 697,985 and 697,986 also are referred to.ALSO:Fibres and foils made from linear aromatic polyesters, e.g polyethylene glycol terephthalate, are treated for a period within the range of 10-4 second to 5 seconds at a temperature above 200 DEG C., e.g. 200 DEG C.,350 DEG C., with a chemical substance which acts as a swelling agent for the polyester under the conditions of the process but does not react chemically therewith, either as such or in the presence of an organic solvent, to improve their dyeing capacity, especially with dispersion dyestuffs.  The swelling agent may be an ester, ether, ketone or nitrile, e.g. the dimethyl and diethyl esters of sebacic, azelaic and suberic acids, benzophenone, adipic acid dinitrile, ethyl-b -naphthol ether and diphenyl ether. The fibres or foils may be passed at a drawoff speed of 10-2000 metres per minute with a path of immersion of 0.5-10 cm. through a bath containing the swelling agent at the required temperature.  Excess swelling agent may then be removed by passing the fibres and foils over a surface heated to 200 DEG -350 DEG C., by passing them through a current of air at a corresponding temperature, by subjecting them to infra-red radiations or by washing, and they may then be chilled in a bath of cold water. Alternatively the fibres or foils may be treated with the swelling agent and heated to the required temperature or the swelling agent may be applied in the gaseous state.  The stiffness and pulling resistance of fibres may be modified by regulating the tension in the fibres during treatment with the swelling agent.  Unfixed polyester continuous filaments which are allowed to shrink during the treatment with the swelling agent may be treated.  Specifications 609,943, 609,944, 609,945, 609,946, 609,947, 609,948, 697,983, 697,984, 697,985 and 697,986 are referred to.