GB755632A - Improvements relating to methods for embossing fabrics - Google Patents

Abstract

755,632. Embossing. BRITISH CELANESE, Ltd. Jan. 10, 1955 [Jan. 12, 1954], No. 884/54. Class 100 (2). A fabric of thermoplastic fibres, e.g. cellulose acetate, is embossed by temporarily softening it by bringing it into contact with a heated pattern while wet with a liquid that assists softening at elevated temperatures, but is not a softening agent at atmospheric temperatures, while the fabric is in a softened condition forcing it into close overall contact with the pattern by sucking down on to it an elastic membrane, the suction acting through perforations in the pattern and the interstices of the fabric. As shown in Fig. 1, a vacuum cup 10 has a perforated platform 14 supporting a pattern 18. A rubber sealing ring 17 is provided on the rim of the cup. A radiant heater is placed over the cup and the pattern is heated before the embossing operation. An elastic membrane 22 attached to a frame 21 is clamped over the mouth of the cup as shown in Fig. 3 and a valve 12, connecting the cup to a vacuum tank, is opened. The air-pressure on the outer side of the membrane causes it to bear down on the fabric 20 and press it against the pattern as shown in Fig. 3. The pattern may consist for instance of a woven wire gauze supported on a gasket of asbestos paper. Patterns can also be made by casting metals, e.g. low-melting alloys or by perforating metal plates. Heat resistant non-metallic materials can also be used, e.g. coarsely woven fabrics of glass-fibre, perforated sheets, mouldings or sintered shapes of heat resistant plastics or of heat resistant compound materials, e.g. glass fibre impregnated with a thermosetting silicone resin. Instead of heating the pattern only, the fabric or both may be heated before the embossing operation. After the fabric is pressed into contact with the pattern and embossed it is cooled, e.g. by a jet of cold air and stripped off. The wetting liquid may be water or an aqueous solution of diethyleneglycol diacetate or of alcohols. The process may be performed in a continuous manner by passing a web of fabric and a web of elastic membrane over a perforated drum carrying patterns on its outer surface. Suction is applied inside the drum and the fabric is heated at one point and cooled at another so as to receive a permanent impression of the patterns. Specification 462,011, [Group VIII], is referred to.