Patent GB-865749-A (GB)
Title: Improvements in plastic sheet material and method of making same
IPC: B29D99/00
Filed: 1959-08-31
Abstract: 865749 Coated fabrics; laminates UNITED STATES RUBBER CO 31 Aug 1959 [19 Nov 1958] 29594/59 [Class 140] Index D1K 20C K20E K20H A plastic sheet material comprises a sheet having a multitude of closely spaced interstices, a coating of organic plastic material on one side of said sheet, and individual protuberances of said plastic material extending through the individual interstices of the sheet and anchored in said coating. The material may take the form of a carpet in which the individual flexible plastic strands are of substantially the same length and in the range of 1/32 to 3/8 inch long, and may have a centre-to-centre spacing in the range of 1/32 to 3/16 inch and having a cross-sectional dimension in the range of 1/64 to 3/16 inch. The term "plastic" refers to natural or synthetic rubber e. g. reclaim rubber or flat bark, natural or synthetic resins such as organic thermoplastic or thermosetting resins e.g. copolymer of vinyl chloride and diethyl maleate, which may contain from 50 to 200 parts of plasticizer per 100 parts copolymer, or mixtures thereof, which may contain a blowing agent to give the plastic a sponge construction, and minor proportions of vinylidene chloride or vinyl acetate. As shown in Figs. 1 and 2, plastic material 19 is introduced between a sheet 11 having a multitude of closely spaced interstices and a backing sheet 15 to form a laminate 11, 20, 15, between rolls 17, 18, which passes under tension around roller 21 which forces a substantially uniform quantity of plastic material through the interstices to form protuberances 23 on one side and a coating 22 on the other side of sheet 11. The material then passes through heater 24 for curing or fusing the material, and the backing sheet 15 separated therefrom or retained to serve as a suitable backing. As shown in Figs.6 and 7, supporting sheet 60 having interstices therein is moved under tension across the surface 62 of screw fed extrusion head 61 to form protuberances 64 on one side and a coating 65 on the other side of said sheet. Small pieces of sheet material may be produced (as shown in Fig. 5) by clamping a laminate comprising a layer of plastic material 31 disposed between sheet 32 having interstices therein, and backing sheet 33 in housing 35. Lower chamber 34 may be evacuated or upper chamber 38 may be pressurized to force material 31 through the interstices of sheet 32 to form the sheet material. Again, small pieces may be made by spreading a layer of plastic on one side of a supporting fabric with a spatula and forcing some of the material through the interstices of the fabric while spreading. As shown in Figs.8 and 9, design patterns may be introduced by stencil coating regions 80 with composition 82 and fused. Thereafter, an extrusion operation may be performed as described to extrude protuberances 81 through the uncoated portions of the fabric. Regions 80 and protuberances 81 may have contrasting colours. Sheets 11, 60, 32 may be woven e. g. in a regular square pattern, or may have a variety of pattern of mesh sizes and shapes, knit or perforated sheet of, for example, cotton which may be sized, rayon, nylon, plastic, paper, metal or glass. Backing sheet 15, 33 may be of polyester, metal, "Cellophane" (Registered Trade Mark) or paper. Specification 802070 is referred to.