Patent GB-500515-A (GB)
Title: A process for manufacturing films, ribbons, foils, threads and fibres
IPC: B29D99/00
Filed: 1938-05-07
Abstract: 500,515. Artificial rubber threads and sheets. NAAMLOOZE VENNOOTSCHAP DE BATAAFSCHE PETROLEUM MAATSCHAPPIJ. May 7, 1938, Nos. 13675, 13676, 13677, 13678, 13679, and 13680. Convention dates, May 8, 1937, May 8, 1937, July 3, 1937, Dec. 22, 1937, April 7, 1938, and April 7, 1938. [Class 70] [Also in Group IV] Threads, fibres, foils, ribbons, and films, are obtained by extruding a solution of a polymerization product of butadiene into a congulation bath consisting of a liquid which does not dissolve the polymerization product but which is preferably readily miscible with the solvent used. The threads or other articles obtained may subsequently be hardened further by a thermal treatment. As solvent for the butadiene polymer there may be used benzene or other aromatic hydrocarbon, or piperylene, cyclohexene, cyclohexane, chloroform, carbon tetrachloride, other chlorinated saturated or unsaturated hydrocarbons, diethyl ether, dioxane, morpholine, ethyl acetate, vinyl acetate, quinoline, or carbon disulphide. The coagulating agent may be methyl, ethyl, or benzyl alcohol, acetone, acetophenone, benzaldehyde, butyraldehyde, water, aniline, triethanolamines, acetic acid, nitrobenzene, phenyl hydrazine, methyl aniline, diethylamine, phenylene diamines, or benzene sulphonic acid. The coagulating liquid may contain additions such as glycerol, soaps, salts, acids or bases. The temperature of the bath may be lower or higher than room temperature. The threads after leaving the first coagulation bath may be passed through another liquid which is miscible with the residual solvent. Coagulation may be carried out at elevated pressure. Spinning may be effected in a V-shaped tube containing the coagulating liquid. The threads may be stretched during the spinning operation. Stickiness may be avoided by passing the threads through a hot liquid, if desired at raised pressure. Hexyl, heptyl, or octyl alcohols, glycols, glycerol, ketones, or esters, may be -used for the hot liquid treatment. Stickiness may also be avoided by using a coagulating bath at a temperature above 100‹ C., or by coating the threads with a substance which reduces the surface tension and preferably has a hydrophobic character, e.g. sulphur in colloidal form, or colloidal sulphides. The threads still containing coagulating liquid may be contacted with a sulphur compound which is decomposed by the coagulation liquid with separation of sulphur. Sulphur chloride may be used, and it may if desired be added to the spinning solution. Substances may be added to the spinning solution or the coagulating bath which react with each other and precipitate sulphur or sulphides in the threads. Instead of sulphur, selenium may be deposited. Hydrogen sulphide may be caused to react with selenous acid so as to form colloidal sulphur and selenium. Stickiness may also be removed by coating the threads with a thin layer of talc, or clay. If the threads are passed through a bath of sulphur chloride under little or no tension, a strong and permanent crimping is obtained. The threads may be subjected to a thermal hardening treatment whereby the tensile strength is increased and the extensibility reduced. Hardening is preferably carried out at a temperature of 120-150‹ C. in the presence of a volatile halogen compound as catalyst, e.g. chlor-benzene, a halogen compound of toluene or xylene, ethyl chloride, ethyl bromide, propyl chloride, cyclohexyl chloride, or halogen ethers. The pressure may be at or below or above atmospheric. The butadiene polymer may be obtained from butadiene itself or from a mixture of butadiene and other diene hydrocarbons, or with polymers of a different character. Co-polymers of butadiene with vinyl compounds may be used. Dyes, plasticizers, fillers, and fire-proofing substances may be added to the spinning solution. In an example, a polymer of butadiene, obtained at room temperature in the presence of sodium as catalyst, is dissolved in benzene and the solution is extruded into methyl or ethyl alcohol. The thread obtained is wound on to a drum which dips into alcohol. The thread is then hardened by heating it in an atmosphere of carbon dioxide containing mono-chlorbenzene. In another example, a solution of butadiene polymer in dioxane is spun into a spinning funnel, the lower part of which passes into a narrow tube dipping into a tank of water. Liquid from the tank is pumped into the top of the funnel so as to maintain a constant level. The funnel is provided with an internal tube which surrounds the spinning nozzle and secludes it from the main stream of coagulating liquid. A small amount of fresh coagulating liquid may be introduced into the inner tube. The thread formed is stretched by the flowing liquid.