Patent GB-441042-A (GB)
Title: Improvements in or relating to the production of artificial filaments, fibres, threads, yarns and like materials
IPC: D02G1/14
Filed: 1935-03-29
Abstract: 441,042. Artificial filaments, fibres, or like materials. BRITISH CELANESE, Ltd., 22, Hanover Square, London. March 29, 1935, No. 9821. Convention date, March 29, 1934. [Class 120 (iii)] Artificial filaments, fibres, and like materials of cellulose or its derivatives are crimped and distorted by pressing the filaments in a softened condition between intermeshing corrugated surfaces, the pressure of which varies at intervals along the length of the filaments, which receive therefore a general crimp along their length and local distortions at the points of varying pressure. The pressure surfaces may be formed on flat metal plates or the faces of intermeshing nip rolls. In order to effect the distortion the apices of the corrugations are flattened, as shown in the Figure, so that the sides of each crimp are subjected to a greater pressure than the apex of the crimp. The filaments may have 1-30 crimps per inch with two distortions in each crimp. The pitch of the corrugations may vary in accordance with the denier of the filament, high denier filaments requiring a coarser pitch than low. The pressure surfaces, e.g. nip rolls may be brought into close contact by means of weights, spring pressure, or hydraulic pressure. The pressing surfaces should be held out of direct contact with one another to avoid cutting the filaments. The filaments are preferably formed into a band and cut into staple lengths after crimping. They may however be cutbefore crimping. If yarns are employed as starting material they should preferably have no, or a low, degree of twist so that the individual filaments may be separated by an opening up process following the crimping and distortion. Yarns with a substantial twist may be employed to yield lengths consisting of a few fibres twisted together. The corrugations may run at right angles or obliquely to a band of filaments being treated, and may have an irregular frequency. The filaments may contain a plasticizer either as a coating or incorporated therein. They may also contain pigments, filling materials, dyes or lakes, fire retardants, de-electrifiers, sizes and lubricants. Suitable fire retardants are beta chloronaphthalene, triphenyl phosphate and tri-cresyl phosphate. Suitable lubricants are olive oil, teaseed oil, mineral oil, alone or with oleic acid, phenol, benzene, or cyclohexanol. Suitable filling and weighting materials are powdered metal, oxides, carbonates or sulphates of metals. Examples of sizes are wax, gelatine, starches, gums, glycerides or resins. Materials preventing the retention of electric charges on the filaments are calcium chloride or nitrate, and the monodi- or tri-ethanolamine salts of fatty acids. Such effect materials may be added to the spinning solution or to the filaments together with a swelling agent. The crimps may be made more permanent by heating one or both of the pressure surfaces. Cellulose materials may be softened before treatment with a 5 per cent solution of sodium hydroxide or ammonia, the pressing members being heated to dry the materials from which the alkali is subsequently washed with water or alcohol. Suitable softeners for cellulose derivative materials are steam, water, aqueous alcohol, alcohol, aqueous acetone, or dilute ethylene dichloride in benzene. The vapours of these softeners are removed by a fan and recovered. Steam employed as a softener should be used near the crimping device to conserve its heat. Dyes may be applied during the crimping process, or while applying the softening agent to the materials. Thus in dyeing and crimping cellulose acetate filaments softening agents such as dilute acetone, alcohol, diethylene glycol, glycol esters or ethers, benzene, toluene, ethylene dichloride or combinations of them that are solvents for dyestuffs as well as having suitable softening properties, may be employed. Thus benzene and ethylene dichloride are solvents for general dyestuffs for thermoplastic derivatives of cellulose and 10-20 per cent of ethylene dichloride dissolved in benzene is a good softening agent for filaments of cellulose acetate with 45 per cent or more of combined acetic acid. When water or steam is used as a softener and rolls heated to 80-100‹ C. are employed, the dyestuffs may be applied as a printing paste which may or may not contain a softener. The colouring matter may be unevenly applied to yield effect threads, or the filaments may be intermittently saponified or a thick printing paste may be applied to the filaments and its concentration thereon varied by the varying distorting pressure. The materials to be crimped may also vary in denier along their length. The crimping and distortion may be effected in conjunction with the usual spinning processes, and the residual solvent may act as softener, suitable adjustments being made in the normal spinning process to ensure a sufficiency of residual solvent, if desired. The crimped or distorted filaments may be wound into packages from which they are stapled or may be grouped together, treated if desired with coating materials and cut by a device as described in Specification 433,110.