Patent ID: 6312777
Filing Date: 2001-11-06
Classification: B32B,G09F,Y10T

Abstract:
In an improved method for making a laminate comprising:(i) coating a first paper sheet having a release surface thereon with a modified pressure sensitive adhesive to form a first laminate;(ii) subjecting said first laminate to conditions suitable to dry or cure the pressure sensitive adhesive; and(iii) marrying the pressure sensitive adhesive side of the thus treated first laminate to the inner surface of a facing layer comprising a continuous film of a vinyl polymer having inner and outer surfaces; said modified pressure sensitive adhesive comprising a water-based pressure sensitive adhesive comprising an acrylic homopolymer consisting of butyl acrylate units and means for decreasing the ""zero minute peel value"" of the facing layer-pressure sensitive adhesive layer combination,the improvement comprising providing and using as said means for decreasing the ""zero minute peel value"" from about 0.1 to 1.0 percent based on the solids content of the pressure sensitive adhesive of an admixture consisting of polysiloxanes (i) and (ii) in intimate combination with the pressure sensitive adhesive, said polysiloxane (i) being substantially water-insoluble and insoluble in said pressure sensitive adhesive and comprising a homopolymer consisting of dimethylsiloxane units and having a viscosity in the range of from 5 cps to 60,000 cps measured at 25.degree. C. with a #4 spindle at 30 rpm; said polysiloxane (ii) being water-soluble and compatible with polysiloxane (i) and consisting of a dimethylsiloxane-oxyalkylene block copolymer wherein the oxyethylene unit of the copolymer contains oxyethylene and oxypropylene substituents, and having a viscosity in the range of from 50 to 5000 cps measured at 25.degree. C. with a #4 spindle at 30 rpm, polysiloxane (i) and polysiloxane (ii) being present in a one to one weight ratio, the amount of polysiloxane (i) in said admixture being effective to separate from the adhesive and to bloom to the adhesive/air interface of said first laminate coated with said adhesive composition to provide efficient repositionability.