Patent GB-1198591-A (GB)
Title: Method and Apparatus for Forming Foraminous Material and Composite Material.
IPC: B29C43/22
Filed: 1969-01-30
Abstract: 1,198,591. Moulding laminated foraminous material by spraying. INTERNATIONAL PLAYTEX CORP. 30 Jan., 1969 [13 Feb., 1968], No. 5265/69. Headings B5A and B5N. Foraminous material is formed continuously by depositing a flowable material such as latex (rubber or plastics) on to the surface of a foraminous former and substantially at right angles thereto, the particles of flowable material being of a size smaller than the openings in the foraminous former. The strands of the former have flat tops with rounded corners and flat sides. The size of the interstices of the former may vary in accordance with a design or pattern having relatively solid and open areas, the pattern being reproduced in the base foraminous product. The latex is applied cylindrically by centrifugal spray discs, and repeated applications build up the desired thickness. Thereafter an adhesive layer is applied and a first ply combined with the base ply to form a laminate. This laminate may be stripped from the forming means, a second adhesive layer applied to the other surface of the base ply and a second ply laminated thereto. The first and second plies may be rubber, wood, paper or cloth and the second material may be cotton fibres, metal or even salt or finely divided carborundum. Figs. 1 and 2 show the various applicatiors i.e. the foraminous conveyer C, the cylindrical latex spraying devices A 1 -A 9 , intermediate drying stations 188, the first adhesive applicator B, the laminating section bringing together the base ply and the first ply 111, the curing oven 189, the stripping section E, and the second adhesive applicator F followed by the second laminating section introducing the second ply 112. The conveyer C is a textile lace fabric or cloth, e.g. bobbinet dacron, specially treated with thermosetting resin, e.g. melamine, urea and phenol formaldehyde resins, and pressed and heated. Treatment with silicone resin and heat curing further renders the conveyer C smooth and strippable. When patterned the open areas have around 400 interstices per square inch and the solid areas from 10 to 100 i.e. the latter have some porosity. The former is held between dacron side strips and the driving chains and is tensioned laterally by an elastic cord (Fig. 3, not shown). Guide tracks (72) and sprockets enable the conveyer to move along cylindrical paths in the base ply forming and adhesive applying sections. Reciprocating and spinning discs 140 apply material at an angle normal to the conveyer in these cylindrical paths and a baffle (146) and mild air bleed (147<SP>1</SP>) ensure a sharp edge to the spray. The latex is fed to the centre of the disc or cone (Fig. 15, not shown), and removable shields round the outside of the conveyer collect the overspray or it proceeds to exhaust via vacuum channels 183. The base ply when stripped from the foraminous conveyer has dished bottoms which receive and hold quantities of adhesive for the attachment of the second ply yet prevent clogging. The plies are pressed together between a continuous belt 210 and a heated drum 206.