| abstract |
This invention relates to pressure-sensitive adhesives, and, more particularly, a composition formed from a blend of pressure-sensitive adhesives. It has frequently been proposed to blend two or more pressure-sensitive adhesive compositions in order to realize the advantages of each. However, mere blending in solution of two or more different pressure-sensitive adhesives most often results in a composition of poor, or at best, compromised properties, and consequently, the blend is of little or no commercial value as a pressure-sensitive adhesive. This invention provides an adhesive composition comprising a blend consisting essentially of (1) an adhesive composition comprising a tacky pressure-sensitive adhesive, said adhesive preferably selected from rubber-based adhesives, e.g., the thermoplastic elastomers, and (2) a pressure-sensitive adhesive composition comprising a polymer having in its backbone at least a major portion by weight of polymerized monomeric acrylic or methacrylic acid ester of a non-tertiary alcohol having from 1 to 14 carbon atoms with the average number of carbon atoms being about 4 to about 12, and grafted to the backbone, polymeric moieties having a Tg greater than about 20°C and a weight average molecular weight above about 2,000. The pressure-sensitive adhesive of adhesive composition (1) has moieties, e.g., blocks or grafts, that associate with the polymeric moieties grafted to the backbone of the polymer of adhesive composition (2). Pressure-sensitive adhesives prepared from the composition of this invention can be tailored to exhibit high values of peel adhesion with respect to both polar and non-polar surfaces, a high level of tack, and a high level of static shear. |