Patent GB-1270504-A (GB)
Title: Process for the production of filaments and films by the melting spinning of acrylonitrile co-polymers
Inventor: GROBE VOLKER
IPC: C08F220/44
Filed: 1970-05-27
Abstract: 1,270,504. Melt spinning acrylonitrile copolymers. CHEMIEFASERKOMBINAT SCHWARZA "WILHELM PIECK" VEB. 27 May, 1970, No. 25501/70. Heading B5B. [Also in Division C3] Filaments are produced by melt spinning a copolymer which has been obtained by copolymerizing a mixture of 50 to 92% by weight of acrylonitrile, 8 to 50% by weight of at least one aliphatic and/or alicyclic alkene containing more than 2 carbon atoms in the molecule and/ or at least one ethylenically-unsaturated carboxylic acid ester, 0.2 to 10% by weight of at least one ethylenically unsaturated sulphonic acid containing at least one sulphonic acid group in the molecule or a salt thereof and, optionally, 1 to 15% by weight of at least one further copolymerizable compound, known polymerization catalysts and methods being used. The copolymer is brought in a screw extruder to a temperature of 150-250‹ C., melt extruded at a rate of 1-10 metres/ minute, the molten filaments thereby formed withdrawn from the spinneret at a draw-down of 8:1 to 100:1, solidified by cooling, and the solidified filaments subsequently stretched at 80-135‹ C. at a stretch ratio within the range of 5:1 and 30:1. The alkene used for making the copolymer may be propene, n-but-1-ene isobutene, 2-methylpentene, hexene, methylcyclopentene, butadiene, isoprene or 2,2-dimethylbutadiene. The ethylenically unsaturated carboxylic acid ester used for making the copolymer is an ester of acrylic or methacrylic acid or an ester of a saturated carboxylic acid with an unsaturated alcohol residue. The carboxylic acid ester may be methyl acrylate, ethyl acrylate, methyl methacrylate, dodecyl acrylate or isopropenyl acetate. The further co-polymerizable compound which may optionally be employed in making the copolymer may be styrene or a derivative thereof, acrylic or methacrylic acid or a derivative of either of these, or a vinyl or vinylidene compound, fumaric or maleic acid or a derivative of either of these or methacrylamide. The sulphonic acid compound used for making the copolymer may be the sodium salt of vinyl-, styrene-, or stilbenesulphonic acid, the sodium, ammonium or an N- alkyl-substituted ammonium salt of alkyl- or methallyl-sulphonic acid, or a sulphoalkyl acrylate or methacrylate. The copolymer may be made by emulsion polymerization with the use of a radical initiator and 0.01 to 0.1% by weight, referred to the monomers, of a ferrous salt. The copolymer may be made by bulk polymerization at a pressure of up to 100 atmospheres and at a temperature of - 40 to 150‹ C. with the use of a radical initiator and irradiaton with ultra-violet light. The filaments, immediately after leaving the spinneret, are cooled by means of a current of cooling air over a length of 0.2 to 2.5 metres and thereby solidified. The cross-section of the spinneret orifices may be either circular or non-circular, and the production of filaments of star-shaped and of flat cross-section is exemplified. Filaments so made may be stretched to ratios of up to 20:1, either by contact with a heated surfacd or passage through a hot liquid, e.g. glycerol at 121‹ C. or hexane triol at 128‹ C.