GB922924A - Process and machine for the continuous manufacture of reinforced sheet material - Google Patents

Abstract

<PICT:0922924/IV(a)/1> An apparatus for producing reinforced material comprises an endless conveyer belt 1, means for imparting a constant and adjustable speed to the belt, means 6 for placing at least one fibrous web 7 on the belt, separate means 8, e.g. a hopper, for applying a layer of thermosetting resinous impregnating material in nonsolid state, e.g. as a liquid or a thixotropic gel, on the web, and at least one heating device <PICT:0922924/IV(a)/2> 4b for setting the resinous material while the web 7 is on the belt 1. A synthetic resin is applied by a roller 3, or by spraying or casting, to the belt 1 which may be metallic, e.g. aluminium, or insultating, e.g. woven or braided glass fibres, and a separating agent, e.g. Carnauba wax or a silicone resin, may be mixed with the applied resin or form a coating on the belt 1. The resin is heated and hardened in an oven 4a and the web 7 is led on at 6d, 6e, a liquid synthetic resin being delivered continuously at 8. The resin may be spread by a doctor blade or projected by spray guns, and is hardened in an oven 4b, the reinforced material being removed from the belt 1 at A2. Rollers 2a, 2b about which the belt 1 is trained are vertically and horizontally adjustable, and the belt 1 may be suitably embossed on its surface. A powder, e.g. nylon dust, glass fibres, silica powder, talc or aluminium powder may be sprinkled on the coated web before it enters the oven 4b to provide a rough surface on the finished product. In a modification, Fig. 2 (not shown), two fibrous webs are applied in succession to the belt 2 each being provided with an impregnating coating, and only the second oven 4b is retained; an intermediate heater between the points of application of the webs may be provided, however. Wiping devices 22, Fig. 4, which may be spring-urged, rotatable about vertical axes 23, force the resin into the web before the second heating. It is stated that strengthening plies, e.g. of the same material as the webs, or of chipboard, may be stuck to the reinforced material. The webs may be fabrics of cotton, cellulose acetate, nylon, glass or metal, or bats of polyester, polyamide, viscose, glass or mineral wool, with or without a binder, or of paper. Three classes of synthetic resins are described:-(i) alkyd resins, with or without accelerators, e.g. melamine, urea or styrene; (ii) cross-linking polyesters which may contain various additives, e.g. catalysts, accelerators, solvents, diluents, and gelatinizing agents, e.g. silica, to form a gel; (iii) polyepoxide resins.