Abstract: Pressure-sensitive adhesive (PSA) compositions containing a crystalline polymeric additive having an M.sub.w of less than 25,000 and a melting point (T.sub.a) greater than 23.degree. C., preferably 30.degree. to 60.degree. , and PSA composites of a backing, preferably a flexible backing, with such a PSA composition coated thereon. The presence of the additive causes the PSA to lose adhesive strength when heated to T.sub.a. The base resin of the PSA is preferably a polyacrylate or a styrene/butadiene copolymer. The additive, which is preferably present in amount 1 to 35%, e.g. 5 to 30%, is preferably a side chain crystallizable (SCC) polymer.

Abstract: Temperature-activated adhesive compositions formulated with crystallizable polymers are provided. The compositions, which display a rapid transition from the tacky to the nontacky state, and/or from the nontacky to the tacky state, are useful in medical applications, where adhesion of a substrate to the skin is desired, as well as in a variety of nonmedical applications. Temperature-activated adhesive assemblies such as tapes, labels, and the like for use in a number of contexts are provided which assemblies have a moisture vapor transmission rate which is compatible with human skin, e.g., above 500 g/m.sup.2 /day at 37.degree. C. and a 100% to 10% relative humidity difference.

Abstract: Food may be packaged and preserved for extended periods using intelligent polymers formed into food containers which have specific and variable gas permeabilities. The polymers used in forming the food packages are intelligent in that they have permeabilities which may be radically and reversibly changed by relatively small changes in temperature. By using different types and formulations of polymers and various temperatures, it is possible to create an environment within the food package which adjusts to the respiration of the food so as to best preserve the color, quality and/or shelf life of the food. The polymers are side-chain crystallizable polymers designed and formulated so as to provide a material which is substantially impermeable to a gas such as oxygen, carbon dioxide or water vapor at a temperature below a given phase transition point and permeable to the same gas at a temperature above that point.