| abstract |
MATRIX FOR RELEASE OF ACTIVE INGREDIENTS ABSTRACT OF THE DISCLOSURE A matrix for delivery of active substances such as fragrances and pheromones into the atmosphere is provided. The matrix is permeable to active substances (including hydrophilic substances), and is formed of a copolymer which can be softened sufficiently at a temperature between 45°C. and 160°C. to incorporate the substances therein without damage caused by heat or chemical reactions, the matrix being formed of a substantially linear block copolymer which is a reaction product of a polydiorganosiloxane which forms soft segments in said reaction product and a diisocyanate which forms hard segments, said copolymer having a glass transition temperature between 45°C. and 160°C., said soft segments comprising from 70 to 99 percent by weight, based on the weight of said copolymer, the average molecular weight of the copolymer being between 15,000 and 500,000, |