GB852380A - Improvements in the manufacture of flexible laminated sheets of organic thermoplastic materials - Google Patents

Abstract

<PICT:0852380/IV(a)/1> <PICT:0852380/IV(a)/2> <PICT:0852380/IV(a)/3> <PICT:0852380/IV(a)/4> <PICT:0852380/IV(a)/5> <PICT:0852380/IV(a)/6> <PICT:0852380/IV(a)/7> Flexible laminated sheets comprising two superimposed laminae of chemically different organic thermoplastic materials, are made by depositing a molten bulk of the first material at a nip between a moving carrying surface and a first contiguous nip-forming surface to form on the carrying surface an adherent layer of said first material travelling away from the nip, carrying this layer while still adherent to the carrying surface into contact with a molten bulk of the second material deposited directly between the adherent layer and a second contiguous surface forming a second nip with the carrying surface, each of the two materials being maintained at the second nip at a temperature above its melting point, and carrying the two materials through the second nip to form on the carrying surface an adherent laminated sheet constituted by superimposed laminae of the two materials securely bonded together. One of the said materials may be an ethenoid polymer and the other may be a pressure-sensitive adhesive. The carrying surface and both contiguous surfaces may be constituted by the surfaces of rotating rolls (Figs. 1 and 2), or the carrying surface may be the surface of a rotating roll and the contiguous surfaces may be stationary (Figs. 3 and 4). The carrying surface may alternatively be a flat surface receiving a rectilinear movement in relation to the contiguous surfaces (Figs. 5 and 6). The laminated sheet may be carried by the carrying surface into contact with a molten bulk of a further thermoplastic material located at a further nip between the carrying surface and a further contiguous nip-forming surface to add by fusion to the laminated sheet a further securely-bonded lamina of the further thermoplastic material, (Figs. 3-7). Preferably the laminated sheet is stripped continuously from the carrying surface. Flexible laminated sheets comprising at least three superposed and p securely-bonded laminae or organic thermoplastic materials, two at least of which are chemically different, are made by depositing said materials in molten condition at successive nips between a moving carrier surface and a plurality of contiguous nip-forming surfaces to form on the carrier surface an adherent laminated sheet constituted by consecutively applied and individually adherent layers of said materials, the temperature at each nip after the first nip being maintained above the melting point of the material applied at that nip and of the material of the layer applied at the preceding nip, and finally stripping the laminated sheet continuously from the carrying surface. Specified materials include polyhydrocarbons and their derivatives (e.g. polyethylene, polyisobutylene, poly-p-xylylene, chlorosulphonated polyethylene, polytetrafluoroethylene, polychlortrifluoroethylene, polyvinylidene chloride, polyisoprene, polybutadiene, polychloroprenes and polystyrene), polyesters (e.g. polyethylene terephthalate, polytetramethylene adipate, and derivatives of 1,4-bis (hydroxymethyl)benzene and sebacic acid), polyamides such as polyhexamethylene adipamide, poly-m-phenylene phthalamide and copolymers of sebacic and adipic acids with hexamethylene diamine, polyurethanes such as the reaction products of ethylene and polyethylene glycols and toluene diisocyanate or other diisocyanates, polyacrylates such as polybutylacrylate, polyacryonitrile, and polypropyl-alpha-chloroacrylate, polyalcohols and derivatives such as polyvinyl alcohol and polyvinyl acetate; silicones; polyethers such as polyethylene oxide; polyamines such as polyvinyl pyridines, and copolymers, interpolymers and block copolymers of the above. Specifications 497,643, 668,274 and U.S.A. Specification 2,274,749 are referred to.