Patent GB-1434481-A (GB)
Title: Process for forming material comprising continuous fibre rein forcement embedded in thermosetting resin
IPC: B29C48/05
Filed: 1974-01-25
Abstract: 1434481 Moulding fibre reinforced resin UBE-NITTO KASEI CO Ltd 25 Jan 1974 [27 Jan 1973] 03487/74 Heading B5A In the production of a fibre reinforced thermosetting resin article, the reinforcement impregnated with the uncured resin is continuously shaped to the section of the article, and the shape is retained, prior to curing of the resin, by coating the exterior surface with thermoplastics extruded around the shape, and drawn on to it by vacuum. The process enables curing to be effected as a separate process, not restricting the rate at which the shape is formed to that required by simultaneous curing, and enables further shaping to be effected prior to curing, either by bending to a curvature or by drawing through a shaping die. The reinforcement may comprise a cloth, or mat, or rovings of glass, vinylon, nylon and polypropylene, the thermosetting resin may comprise polyester, epoxy or phenol resin, and the thermoplastics may comprise polyethylene, polypropylene, polyvinyl chloride or nylon. In the Fig. 1 embodiment (not shown), glass fibre rovings are drawn through a polyester resin impregnation bath, and then shaped, upstream of the extrusion die, to a circular rod configuration in vertically downward passage through a series of circular shaping plate apertures of progressively decreasing size. The shape 5, Fig. 4, then passes through a die passage 9, which is cooled by water circulating at 15a, and high density polyethylene is extruded therearound as a tube 12a, which is inwardly directed by a tapered nozzle plate 17a, and is drawn on to the shape by the vacuum applied at 16a and which functions also to remove vapours from the thermoplastics, and bubbles from the resin. The high density polyethylene coating issuing from the die, is cooled in vertical downward passage into a water cooling bath, wherefrom it is drawn by rollers to be delivered in flexed form into a container. The coated shape may be cut into lengths which are bent, and cured by heating, or may be drawn from the container and by rollers through a hot water curing tank, and then cut to length. In the Fig. 5 embodiment for forming a tube, a chopped glass strand mat 30, between layers of polyester resin impregnated rovings 1, is wrapped around a high density polyethylene tube 33, continuously extruded from a die 34 around a mandrel 35 and cooled by a means 36 and water tank 37. The external shaping is effected, as in the Fig. 1 embodiment, by passage through circular apertures of decreasing size in plates 32, and an external coating of high density polyethylene is applied by die 8C, and cooled in being drawn through a cooling tank 19b by a device 22a, prior to cutting at 39. For making a flexible tubular shape, which is bent before (airing) curing, the mandrel 35 is extended to the inlet of the tank 19b and the pipe 33 is either of a sufficient thinness, or made of flexible material. A plurality of coated tubes may be cured in linear configuration, by simultaneous drawing through a hot water tank, by opposed endless belts, Fig. 6 (not shown). In the Fig. 8 embodiment (not shown), the shape comprises a flat sheet of chopped glass strand mat between resin impregnated mats, what are similarly shaped upstream of a die from which a thermoplastics coating is applied as a tetrahedral conical shape issuing from the die. The coated shape is delivered by rollers through a cooling tank, and in flexed form into a container. The sheet may be cured in its shaped form similarly to the Figs. 2 and 6 embodiment, or may be further shaped in corrugated or channel shaped form by drawing, by opposed endless belts, through a shaping die aperture having the requirement configuration Figs. 11 and 12 (not shown), and located at the inlet to a hot water curing tank. The shape may be of angle configuration. The rod of the Fig. 2 embodiment may comprise a glass fibre content of up to 75%, and the tube of the Fig. 5 embodiment comprises 65%.