Patent GB-1099236-A (GB)
Title: Dry-cleanable expanded plastic laminates and methods of making same
IPC: B29C39/26
Filed: 1965-01-14
Abstract: A flexible laminate having desirable drape properties comprises a backing of fibrous material and a polyesterurethane foam layer in contact with said backing and having one face adhered thereto, the foamed layer having a more dense surface portion on opposite sides of an intermediate less dense portion, one of the more dense portions being attached to the backing, the interior and one face of the backing being substantially free of polyurethane.  A skin coating of a copolymer from an isocyanate-containing polyester urethane prepolymer (or a mixture of a polyester having at least two hydroxyl groups and excess polyisocyanate) and an active hydrogen-containing extender may be adhered to the outermost surface portion of the foamed layer.  The outermost surface portion of the foam layer, or if present the skin coating is flocked, e.g. by application of a natural or synthetic rubber cement, and then wool, cotton or nylon fibres. The components of the skin coating may comprise a major amount of active hydrogen groups in the extender and a minor amount of isocyanato groups in the prepolymer (or of excess isocyanato groups in the mixture). The laminate having the skin coating may also have a top coat comprising a copolymer from an isocyanate-containing polyester urethane prepolymer (or a mixture of a polyester having at least two hydroxyl groups and excess polyisocyanate) and an active hydrogen-containing extender adhered to the outermost surface portion of the skin coating, the components of the top coat comprising a major amount of active hydrogen groups in the extender and a minor amount of isocyanato groups in the prepolymer (or of excess isocyanato groups in the mixture).  The active hydrogen-containing extender used to form the outermost layer of the laminate remote from the backing may comprise a cellulose acetate butyrate of the general formula (C12H14O4(R)x(R1)y)z where R represents OCOCH3 and/or OH, R1 represents OCOC3H7 and/or OH, x and y represent any number from 1 to 5 and z represents any number greater than 3, or a vinyl resin copolymer containing functional groups reactive with isocyanates. The vinyl resin copolymer may be selected from partially hydrolysed vinyl chloride/vinyl acetate copolymer, a vinyl copolymer made from 86% vinyl chloride, 13% vinyl acetate, and 1% maleic acid (0.7% carboxyl content), copolymers of vinyl chloride and beta hydroxyl ethyl acrylate, copolymers of vinyl chloride, methyl methacrylate and beta hydroxy propyl acrylate.  The maximum cell size in the foam layer may be 10 mils and the foam layer may have at least 50% open cells.  The backing may consist of a knitted fabric with substantial elongation in all directions in the plane of the fabric, or any stretchable fabric which may be of rayon, felt, canvas, cotton, or a synthetic fibre such as nylon or Dacron (TM).  The flexible laminate may be produced by forming on a release carrier 11, a thin layer 8 of foamable liquid adapted to solidify to a polyester urethane foam, allowing the liquid to solidify and set up to a non-flowable foam with a dense surface portion on opposite sides of a less dense portion, at least the exposed surface being tacky, superimposing a fabric backing layer 21, e.g. a knitted fabric with substantial elongation in both directions, on the tacky surface of the foam with pressure sufficient to cause adhesion without the foam penetrating right through the backing layer, curing the foam to the non-tacky state, and stripping the composite of foam and backing layer from the carrier.  A skin coating 6 from a copolymerisable mixture comprising an isocyanate-containing polyester urethane prepolymer (or a mixture of a polyester having at least two hydroxyl groups and excess polyisocyanate) and an active hydrogen containing extender may be formed on the release carrier 11 prior to the formation of the thin layer 8 of foamable liquid.  The components of the skin coating may comprise a major amount of active hydrogen groups in the extender and a minor amount of isocyanateto groups in the prepolymer (or of excess isocyanato groups in the mixture).  After stripping the laminate including the skin coating from the carrier, a top coat 41 comprising a copolymer from an isocyanate-containing polyester urethane prepolymer (or a mixture of a polyester having at least two hydroxyl groups and excess polyisocyanate) and an active hydrogen containing extender may be applied to the skin coating 6, the component of the top coat comprising a major amount of active hydrogen groups in the extender and a minor amount of isocyanato groups in the prepolymer (or of excess isocyanato groups in the mixture).  The surface remote from the fabric backing may then be flocked.  The foamable liquid may include as a principal blowing agent, one or more fluorinated or flourinated and chlorinated hydrocarbons boiling below 150 DEG C, and may also contain as foam stabiliser an ionic methoxy capped copolymer of dimethyl polysiloxane and polyethylene oxide.  Examples of suitable release carriers are given.