Film-forming copolymers and their use in water vapor permeable coatings

• US 5,169,906 A
• Filed: 03/21/1991
• Issued: 12/08/1992
• Est. Priority Date: 04/26/1990
• Status: Expired due to Fees

• Current Assignee: Dow, Inc.
• Original Assignee: Dow, Inc.
• Inventors: Cray, Stephen E., Rowlands, Martin
• Primary Examiner(s): Marquis, Melvyn I.
• Assistant Examiner(s): AYLWARD, DAVID E
• Application Number:
  US07/672,993
• Time in Patent Office: 628 Days
• Field of Search: 525/453, 525/474
• US Class Current: 525/453
• CPC Class Codes: D06M 15/564 Polyureas, polyurethanes or other polymers having ureide or urethane links; Precondensation products forming them
• CPC Class Codes: D06M 15/643 containing silicon in the main chain
• CPC Class Codes: D06M 15/647 containing polyether sequences
• CPC Class Codes: Y10T 428/31551 Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.]
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane
• CPC Class Codes: Y10T 442/2139 Coating or impregnation specified as porous or permeable to a specific substance [e.g., water vapor, air, etc.]
• CPC Class Codes: Y10T 442/223 Organosilicon containing

Abstract

A film-forming copolymer is formed by copolymerising 100 parts of a curable polyurethane resin and 10 to 100 parts of an organosilicon compound, consisting essentially of SiO₂, R₃ SiO_1/2 and R'"'"'R₂ SiO_1/2 units, the ratio of monovalent units to tetravalent units being from 0.4/1 to 2/1 and from 40 to 90% of and monovalent units being R'"'"'R₂ SiO_1/2 units. R is a monovalent hydrocarbon group having up to 8 carbons and R'"'"' denotes a OH-terminated polyoxyalkylene group. The invention also includes a method of making fabrics waterproof and permeable to water vapor by coating it with such copolymer.

Claims

1. A copolymer formed by the copolymerisation of 100 parts by weight of a curable polyurethane resin and 10 to 100 parts by weight of an organosilicon compound, consisting essentially of tetravalent SiO₂ units and monovalent R₃ SiO_1/2 and R'"'"'R₂ SiO_1/2 units, wherein the ratio of monovalent units to tetravalent units is from 0.4/1 to 2/1 and from 40 to 90% of all monovalent units present in the organosilicon compound are R'"'"'R₂ SiO_1/2 units wherein R denotes a monovalent hydrocarbon group having up to 8 carbon atoms and R'"'"' denotes a polyoxyalkylene group which is terminated by a hydroxyl group.

2. A copolymer according to claim 1 wherein the polyurethane resin is an aqueous two component polyurethane resin composition having a solids content in the range from 35 to 50% by weight.

3. A copolymer according to claim 1 wherein the polyurethane resin is a solvent based two component polyurethane resin composition having a solids content in the range from 35 to 50% by weight.

4. A copolymer according to claim 1 wherein at least 80% of all R groups in the organosilicon compound are selected from the group consisting of lower alkyl and aryl groups.

5. A copolymer according to claim 1 wherein in the group R'"'"' at least 80% of all the oxyalkylene groups are oxyethylene groups, all polyoxyalkylene groups being attached to a silicon atom via --SiC-- bonds.

6. A copolymer according to claim 1 wherein the polyoxyalkylene groups have a molecular weight of from 300 to 1000.

7. A copolymer according to claim 1 wherein the ratio of monovalent to tetravalent siloxane units in the organosilicon compound is from 1.3/1 to 1.8/1.

8. A copolymer according to claim 1 wherein the ratio of monovalent to tetravalent siloxane units in the organosilicon compound is from 1.4/1 to 1.6/1.

9. A copolymer according to claim 1 wherein 15 to 70 parts of the organosilicon compound are used for every 100 parts by weight of the polyurethane resin.

10. A copolymer according to claim 1 wherein 17 to 50 parts of the organosilicon compound are used for every 100 parts by weight of the polyurethane resin.