Patent GB-357154-A (GB)
Title: Manufacture of artificial threads and other materials from cellulose compounds
IPC: D01F2/28
Filed: 1930-03-15
Abstract: Artificial silk, films, and other products are made by acting on a cellulose compound containing at least one CSS - group with a di- or polyhalogen paraffin in which at least two halogen atoms are attached to the same carbon atom, and after bringing the product into the appropriate shape or form, acting thereon with a coagulating agent. The coagulating agent may also have a plasticizing effect on the freshly coagulated material.  The material may first be treated with a coagulating agent and then with a plasticizing agent.  The reacting mixture of viscose with a halogen paraffin of the type specified may be subjected to prolonged stirring.  Instead of adding the halogen paraffin to viscose, substances may be added which by reaction will produce a halogen paraffin.  The solution of the product may be extruded into any one of the coagulating baths known in the viscose art. When plasticizing baths are employed, sulphuric acid solutions of not less than 30 per cent may be used.  Equivalent strengths of other mineral acids such as hydrochloric acid, nitric acid, phosphoric acid, or arsenic acid, or other plasticizing agents such as zinc chloride solution may be used.  The mineral acids may be mixed with salts such as sodium sulphate or bisulphate, ammonium sulphate or bisulphate, sodium sulphite or bisulphite, magnesium or zinc sulphate, sodium nitrite.  Other substances such as boric acid, glycerine, glucose, alcohol, a salt of aniline or pyridine, an aldehyde, acetic acid, formic acid, lactic acid, or oxalic acid may be added.  When a coagulating bath and a plasticizing bath are used, the first may be of such a nature that the cellulose compound coagulates in water soluble or water insoluble form.  In the preparation of the viscose, the cellulose used may be wood pulp or cotton linters which has been treated with acids or alkalis, or it may be regenerated cellulose in any form such as artificial fibres. In examples, ethylidene chloride, methylene chloride, propylidene or isopropylidene chloride, tetrachlorethane, or pentachlorethane are stirred with viscose for several hours and allowed to age for about four days stirring taking place each day for several hours.  The solution is filtered and spun into strong sulphuric acid of 40-70 per cent strength. Copper acetate or zinc acetate may be added to the viscose before the addition of the halogen compound.  In the preparation of the alkali cellulose the cellulose may be directly mixed with the required amount of caustic soda solution.  In other examples, the solution of the cellulose compound is spun into ammonium sulphate solution, or a dilute sulphuric acid solution containing sodium bisulphate, or sodium sulphate, ammonium sulphate, zinc sulphate, and glucose dissolved in dilute sulphuric acid.  In another example, cotton material is impregnated or coated with a solution of the compound of viscose and a halogen paraffin of the type specified, to which solution filling material such as talc, or china clay, or a pigment such as mica, or lampblack may be added. The material is then passed under tension through a coagulating or plasticizing bath, and then washed and dried.  Halogen derivatives of di- or polyhydric alcohols such as a -monochlorhydrin, a -dichlorhydrin, or ethylene chlorhydrin may be mixed with the reaction mass of viscose and halogen paraffin.  The Provisional Specification also refers to the use of chlorhydrins instead of halogen paraffins.  Specifications 335,906, [Class 2 (ii), Cellulose &c.], 341,843, 357,121, 357,192 and 357,526 are referred to.