Patent GB-748368-A (GB)
Title: Improvements relating to continuous production of corrugated reinforced plastic material
IPC: B32B27/00
Filed: 1953-08-31
Abstract: 748,368. Corrugating resin-fibre material. MONTECATINI SOC. GENERALE PER L'INDUSTRIA MINERARIA E CHIMICA. Aug. 31, 1953 [Sept. 16, 1952], No. 23981/53. Class 87(2) Rolled, corrugated, polyester resin plastic material reinforced with fibrous material, preferably with a layer of glass fibre, is continuously produced by a method in which the reinforcing layer is progressively subjected to rolling. pressure whereunder the resin in liquid form is distributed from a reservoir in sufficient quantity to fill the interstices between the fibres for the formation of a compact rolled flat material and transverse corrugations are formed and maintained in the material in a suitably conditioned atmosphere at regulated temperature until polymerization is effected. Glass fibre mat material is drawn from a roll 1 into the nip between two rubber- or ebonite-faced rollers 3, 3', the roll 1 being slightly braked to preserve tension. As the rollers 3, 3<1> rotate they unwind from two braked rolls 4, 4<1> two bands of flexible, non-porous, non-adhesive material resistant to the polymerization conditions, such as viscose foil, which pass round the rollers and sandwich the fibre between them, and the surface of these bands which become the inner surfaces are coated with liquid polyester resin fed from a reservoir 2 by compressed air These bands constitute both a mould and a conveyer, and keep the resin from contact with the rest of the apparatus and exclude air which would hinder polymerization. The bands are materially wider than the fibre layer to allow for seepage of the resin, which is also controlled by two aluminium strips, not shown, shaped according to the curvature of the rollers 3, 3<1> and held against them by springs at a small distance from each edge of the fibre layer. The feeding of the resin is regulated so that two resin beadings are formed at 5, excess being collected in acontainer 6 and re-cycled. The pressure between the rollers 3, 3' must be regulated so as to allow sufficient resin to penetrate the interstices of the fibre without admitting air, and adjusting screws with graduated handwheels, not shown, are therefore fitted. In a modification two fibre layers are fed vertically from two rolls into the nip of rollers with the axes in a horizontal plane, resin being fed on to bands of viscose foil as before and additionally, if desired, between the two fibre layers as they enter the nip. Polymerization of the rolled material takes place in a chamber 7 heated by steam coils or other means. This chamber also contains the corrugating apparatus, which comprises two chains 10, 10<1> each carrying a series of equally sized rollers 9, 9<1>, the uppers rollers 9<1> fitting between the lower rollers 9. The rollers need not be cylindrical, but may be, e.g. hexagonal. The material is drawn between the chains and corrugations thereby impressed on it by the rollers 9, 9<1>. The chain 10 carrying the lower rollers slides over a flat support 11, and the upper rollers 9' are guided into the spaces between the lower rollers by two guides 13, 13<1>. To keep the spacing between the upper and lower rollers constant the latter are fitted with collars 12, Fig. 5, which bear on the upper rollers. The rollers 9 are firmly supported on the chains 10 but some play is allowed between the rollers 9<1> and the chains 10<1>. To control the stretch of the rolled material the chains are driven from the motor 14 through a variable speed transmission, the same motor also driving, without the interposition of speed changing means, the two pressing rollers 3, 3<1>. At the exit from the chambers 7 the flexible bands are separated from the rolled and corrugated material by rolls 15, 15' and the material is side finished by two circular saws 16, 16<1> and then reeled. The polyester resin should have a viscosity of 4-6 poises, a suitable composition being specified. The resin may be coloured with mineral pigments. A suitable fibre mat weighs about 450 grammes per square metre and has fibres with an average length of 5 cm. preferably sized with a polystyrene emulsion.