Patent GB-560660-A (GB)
Title: Improvements in and relating to the production and treatment of vinyl compounds
IPC: C08F8/20
Filed: 1942-01-27
Abstract: Synthetic resin masses suitable for the manufacture of films, sheets, insulating materials, moulded articles, coating compositions, adhesives and impregnating agents, and particularly adapted for the production of filaments and fibres are prepared by chlorinating a solution or dispersion of a co-polymer of vinyl chloride and vinyl acetate having a molecular weight of at least 15,000 and containing 80/95 per cent by weight of vinyl chloride until the final product has a total chlorine content from 58/64 per cent by weight, whereby it acquires a shrinkage temperature range above 100 DEG  C. and is soluble to the extent of at least 6 per cent in acetone, methyl ethyl ketone, butanone, chloroform or dioxane and may be soluble in s-dichlorethane, s-tetrachlorethane or morpholine.  Preferably the co-polymer contains 88/90 per cent of vinyl chloride and the final product contains 59/62 per cent by weight of chlorine.  Chlorination preferably takes place in solution at 50/55 DEG  C. in the presence of an organic peroxide catalyst.  The chlorinated co-polymer is precipitated from solution by pouring into a large volume of non-solvent, e.g. isopropanol or n-butanone.  This precipitation may consist of a wet spinning step with stretching up to 200 per cent accompanying the extrusion process, or the resin may be precipitated in flocculant form, washed, dried, and the powder, if desired, p redissolved for either wet or dry spinning.  The threads may be after-stretched whilst subjected to temperatures above their shrinkage temperature range, the temperature being maintained for some time after the stretching process.  Example 1 described chlorination for 12 hours at 55 DEG  C. of a co-polymer containing 90 per cent vinyl chloride and having a molecular weight of 22,000 whilst dissolved in chloroform containing benzoyl peroxide.  The mixture is freed from hydrogen chloride and wet spun into isopropanol.  The spun thread is stretched over godets, washed, collected in a spinning box and air dried.  Example 2 is similar but the chlorinated product is precipitated by pouring into butanol the precipitate being redissolved in chloroform for the wet spinning process.  The thread is spun in isopropanol with 38 per cent stretching and after washing and drying is after-stretched by 580 per cent while being steam heated at 159 DEG  C.  Example 3 describes chlorination for six hours at 50 DEG  C. of a copolymer, having a molecular weight of 30,000, and containing 95 per cent of vinyl chloride, whilst suspended in carbon tetra-chloride containing benzoyl peroxide.  During chlorination the particles pass into a solution and form a gelled mass which dissolves on addition of dioxane.  The product is precipitated by pouring into isopropanol, washed and dried.  It is redissolved in dioxane and wet spun into isopropanol with 100 per cent stretch during spinning.  Example 4 is similar to Example 1 but the precipitated thread is redissolved in acetone and dry spun with a 15 per cent stretch during spinning and an after-stretch of 1070 per cent while the thread is steam heated to 148 DEG  C.  The examples describe the properties of the final threads.  The threads may be cut into short lengths for staple fibre. Suitable coagulants for the wet spinning processes are water, isopropanol, normal butanol, normal hexanol, normal octanol, cyclohexanol, normal decanol, hydrocarbons such as petroleum ether, Sinclair Solvent, Ultrasene and cyclohexane.  The chlorinated co-polymer compositions may contain pigments, fillers, plasticizing agents, delustrants, lubricants and sizing or finishing agents. Directions are given in the Specification for determining the amount of chlorination necessary to produce a desired shrinkage temperature range from a co-polymer of given properties.  Specifications 401,200, 422,957, 513,327, 517,689, 518,555, 518710, and French patent No. 828,077 are referred to.