Patent GB-1061891-A (GB)
Title: Adhesive sheet materials
IPC: C09J7/38
Filed: 1964-01-30
Abstract: 1,061,891. Coated sheet material. MINNESOTA MINING & MANUFACTURING CO. Jan. 30, 1964 [Feb. 14, 1963], No. 4012/64. Heading B2E. [Also in Divisions B5 and B6] A sheet material comprises on one or both surfaces a layer of tacky adhesive and a quantity of frangible or collapsible, non-adhesive, hollow protrusions which may be microspheroids or micro balloons having sufficient uniformity of distribution to allow the adhesive surface to be slid about on the surface of an adhesive-receptive surface without adhering thereto, which protrusions are collapsible by applied pressure, to cause the surfaces to adhere to each other. The sheet material may comprise a self-sustaining strip of adhesive 33 having microspheres 14 partially embedded on each surface. The protrusions may cover from 1/10 to 1/3 of the adhesive surface and may have 1/4 to 1/3 of their diameter above the surface of the adhesive. A supporting and protecting liner may be in releasable contact with the adhesive surface and with the protrusions. The liner may have a plastic surface layer and may be formed with surface depressions which closely complement the portions of the protrusions which protrude from the surface. The protrusions may be embedded in a supporting and protecting liner and a layer of adhesive provided thereover, the adhesive and protrusions being in releasable contact with the supporting liner. The adhesive coating may be pressure sensitive or self-adhesive. As shown, carrier 10 e.g. paper having a thermoplastic polymer coating 27 which may have a further release coating e.g. of silicone, thereon is drawn past source 12 of microspheroids 14, heated in oven 16 in order that the microspheroids penetrate into the softened coating, and under coating hopper or spreader bar 17 where it is coated with a solution of pressure sensitive adhesive 18. The adhesive coating 29 is dried and the solvent removed in oven 19. A protective and decorative film 21 e.g. a pigmented plastic film, is united with the dry tacky adhesive surface by pressure applied between squeeze rolls 23, 24. The thermoplastic polymer may be polyethylene. The walls of the microspheroids may be composed of a resin or polymer e.g. urea-formaldehyde, alkali silicate or glass. The adhesive may consist of a copolymer of fusel oil acrylate and acrylic acid, or 2-ethylbutyl acrylate and ethyl acrylate, in a mixture of ethyl acetate and heptane. The protective film may be composed of a vinyl chloride-vinyl acetate copolymer, plasticizer, pigment, stabilizer and lubricant. The film may be coated with an adhesive primer composition before application to the adhesive surface. Alternatively the microspheroids may be simultaneously embedded by pressing an adhesive coated film on to a thermoplastic coated carrier, the microspheroids having been previously applied to either the adhesive or thermoplastic coating. The adhesive coated film may be produced by application of a preformed adhesive layer to the film layer. The sheet material is applied to a substrate surface e.g. wall, metal signboard, concrete or wood floor, by stripping the thermoplastic coated carrier 10 from the adhesive coated film 21 bearing the microspheroids 14, placing the adhesive coated film into the required position on the substrate, the microspheroids spacing the adhesive from the substrate surface, and pressing to collapse the microspheroids and permit the adhesive layer 29 to contact and adhere to the substrate surface. Sheet material comprising carrier 10, thermoplastic coating 27, release coating 30, microspheroids 14 and adhesive coating 29 may be adhered by the adhesive coating to substrate surface 31. Carrier 10 bearing coatings 27 and 30 may then be removed and permanent floor surfacing material 32 e.g. a vinyl floor tile, slid into position over the exposed microspheroids 14 and adhered to the adhesive coating 29 by the application of pressure to collapse the microspheroids.