Container, method and composition for controlling the release of a volatile liquid from an aqueous mixture
First Claim
1. In a container for controlling the release from said container into the adjacent atmosphere of at least one volatile liquid ingredient of an aqueous mixture, where(1) at least one wall of said container comprises at least one release-controlling layer of a solid material that is inert with respect to said mixture and permeable to said ingredient, and(2) said layer comprises an inner surface in contact with said mixture and an outer surface in contact with said atmosphere,the improvement comprising the presence of said layer as a 0.001 to 1 mm.-thick film or coating of a substantially linear dimethylsiloxane/oxyethylene/urethane copolymer comprising from 20 to 40 weight percent of hard segments consisting essentially of polyurethane units derived from an organic diisocyanate and an alkylene diol, and form 60 to 80 weight percent of soft segments comprising from 15 to 65 percent by weight, based on the weight of said copolymer, of a hydrophobic portion consisting essentially of at least one sequence of from 15 to about 100 dimethylsiloxane units and from 10 to 65 percent by weight, based on the weight of said copolymer, of a hydrophylic portion consisting essentially of at least one sequence of from 5 to 70 oxyethylene units, where the molar ratio of hard to soft segments is from 2.5 to 7.
1 Assignment
0 Petitions
Accused Products
Abstract
Films and coatings formed from a specified class of organosiloxane/urethane copolymers are unique by virtue of their high permeability to volatile ingredients in the form of aqueous compositions and their inertness to the ingredients of these compositions. Containers wherein at least a portion of the walls comprise films or coatings formed from these copolymers are used to achieve the controlled release of volatile fragrances and biologically active agents from aqueous compositions confined within the container into the adjacent atmosphere.
-
Citations
8 Claims
-
1. In a container for controlling the release from said container into the adjacent atmosphere of at least one volatile liquid ingredient of an aqueous mixture, where
(1) at least one wall of said container comprises at least one release-controlling layer of a solid material that is inert with respect to said mixture and permeable to said ingredient, and (2) said layer comprises an inner surface in contact with said mixture and an outer surface in contact with said atmosphere, the improvement comprising the presence of said layer as a 0.001 to 1 mm.-thick film or coating of a substantially linear dimethylsiloxane/oxyethylene/urethane copolymer comprising from 20 to 40 weight percent of hard segments consisting essentially of polyurethane units derived from an organic diisocyanate and an alkylene diol, and form 60 to 80 weight percent of soft segments comprising from 15 to 65 percent by weight, based on the weight of said copolymer, of a hydrophobic portion consisting essentially of at least one sequence of from 15 to about 100 dimethylsiloxane units and from 10 to 65 percent by weight, based on the weight of said copolymer, of a hydrophylic portion consisting essentially of at least one sequence of from 5 to 70 oxyethylene units, where the molar ratio of hard to soft segments is from 2.5 to 7.
- 6. In a method for achieving release of at least one volatile liquid ingredient of an aqueous mixture into a gaseous atmosphere at a controlled rate by separating said mixture from said atmosphere by means of a release controlling layer of a solid material that is inert with respect to said mixture, from 0.001 to 1 mm. thick and permeable to said ingredient, where the improvement is characterized by selecting the material of said release controlling layer from substantially linear dimethylsiloxane/oxyethylene/urethane block copolymers comprising from 20 to 40 weight percent of hard segments consisting essentially of polyurethane units derived from an organic diisocyanate and an alkylene diol, and from 60 to 80 weight percent of soft segments comprising from 15 to 65 percent by weight, based on the weight of said copolymer, of a hydrophobic portion consisting essentially of at least one sequence of from 15 to about 100 dimethylsiloxane units and from 10 to 65 percent by weight, based on the weight of said copolymer, of a hydrophylic portion consisting essentially of at least one sequence of from 5 to 70 oxyethylene units, where the molar ratio of hard to soft segments is from 2.5 to 7.
Specification