Water-swellable material comprising coated water-swellable polymers
First Claim
1. A water-swellable material, comprising water-swellable polymers that are coated with a coating agent, which comprises an elastomeric material that is phase-separating, having at least a first phase with a first glass transition temperature Tg1 and a second phase with a second glass transition temperature Tg2, and wherein said elastomeric material is a block copolymeric material, having a molecular weight of at least 50 kDa and wherein said block copolymeric material further comprises at least one block copolymer selected from the group consisting of polyurethane-co-polyethers, polyurethane-co-polyesters, polyurethane/urea-co-polyethers, polyurethane/urea-co-polyesters, polystyrene block copolymers and blends thereof.
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Abstract
This invention relates to a water-swellable material comprising water-swellable polymers that are coated with a coating agent that comprises a phase-separating elastomeric material, which allows swelling of the water-swellable polymers, without breakage of the coating. The invention also relates to a process of making specific coated water-swellable polymers using a phase-separating elastomeric material, and materials obtainable by such a process.
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12 Claims
- 1. A water-swellable material, comprising water-swellable polymers that are coated with a coating agent, which comprises an elastomeric material that is phase-separating, having at least a first phase with a first glass transition temperature Tg1 and a second phase with a second glass transition temperature Tg2, and wherein said elastomeric material is a block copolymeric material, having a molecular weight of at least 50 kDa and wherein said block copolymeric material further comprises at least one block copolymer selected from the group consisting of polyurethane-co-polyethers, polyurethane-co-polyesters, polyurethane/urea-co-polyethers, polyurethane/urea-co-polyesters, polystyrene block copolymers and blends thereof.
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3. A process for making a water-swellable material that comprises coated water-swellable polymer particles, said process comprising the steps of:
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a) obtaining water-swellable polymer particles; b) applying a coating agent, wherein said coating agent of step b) comprises an elastomeric phase-separating material that has at least a first phase with a first glass transition temperature Tg1 and a second phase with a second glass transition temperature Tg2, to at least a part of said water-swellable polymer particles and wherein said elastomeric material is a block copolymeric material, having a molecular weight of at least 50 kDa and wherein said block copolymeric material further comprises at least one block copolymer selected from the group consisting of polyurethane-co-polyethers, polyurethane-co-polyesters, polyurethane/urea-co-polyethers, polyurethane/urea-co-polyesters, polystyrene block copolymers and blends thereof.; and
optionally the step ofc) annealing the resulting coated water-swellable polymer particles of step b), so as to obtain said water-swellable material. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11)
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Specification