| 摘要 |
716,702. Plywood; bending wood. HOLOPLAST. Ltd. Dec. 22, 1950 [Dec. 29, 1949], No. 33250/49. Class 145 (2) [Also in Group VIII] Corrugated plastic laminates are made from fibrous sheet material impregnated with a thermosetting resin by preliminarily corrugating or pleating the sheet material to an approximation of the desired final form, stacking the pre-formed sheets, and consolidating the stack between heated, corrugated platens. The fibrous material may be Kraft paper, textile material, wood veneer, woven glass fibres, or a combination of two or more of these materials. The resin may be a phenol-, cresol-, urea-, or melamine - formaldehyde resin. The impregnated sheets may be pleated by hand, or a web of impregnated material may be pleated longitudinally by the apparatus described in Specification 716,703, [Group VII]. The pleated sheets, which may have been cut from a pleated web, may be assembled on a rack 19, Fig. 8, consisting of triangular sectioned bars 20 secured to cross-battens 21, before the consolidating operation. A multidaylight hydraulic press may be used so that a number of laminated corrugated sheets are formed simultaneously. A group of laminates may be formed in each daylight by stacking a number of laminate assemblies 23, Fig. 10, one upon the other with a flexible or limp separating layer 28, between each pair as described in Specification 654,645, [Group VIII]. If desired, there may be present between the outermost laminate assembly of each group and the adjacent platen 288, (a) a flexible or limp separating layer 29, (b) a metal cover plate 26 corrugated to match the corrugations in the platen, and (c) in the case where the fibrous material is Kraft paper which yields a "hammered" finish when a number of laminates are pressed simultaneously, one or more sheets 31 of the same paper, preferably unimpregnated, may be provided between the cover plate 26 and the separating layer 29 in order to give the same finish on the outer surface of the outer laminate. The platens may be those described in Specification 716,755, [Group VIII]. |
