Cross-linked water-swellable polymer particles

• US 4,059,552 A
• Filed: 10/23/1975
• Issued: 11/22/1977
• Est. Priority Date: 06/21/1974
• Status: Expired due to Term

• Current Assignee: The Dow Chemical Company (Dow, Inc.)
• Original Assignee: The Dow Chemical Company (Dow, Inc.)
• Inventors: Lamphere, Jack C., Zweigle, Maurice L.
• Primary Examiner(s): Levin, Stanford M.
• Application Number:
  US05/625,297
• Time in Patent Office: 761 Days
• Field of Search: 260/29.6 TA, 260/29.6 H, 260/29.6 PM
• US Class Current: 524/555
• CPC Class Codes: C08F 2/32 Polymerisation in water-in-oil emulsions
• CPC Class Codes: C08J 2300/14 Water soluble or water swellable polymers, e.g. aqueous gels
• CPC Class Codes: C08J 3/12 Powdering or granulating
• CPC Class Codes: C08L 33/062 Copolymers with monomers not covered by C08L33/06
• CPC Class Codes: C08L 33/26 Homopolymers or copolymers of acrylamide or methacrylamide
• CPC Class Codes: C09D 7/43 Thickening agents
• CPC Class Codes: Y10S 507/902 Controlled release agent
• CPC Class Codes: Y10S 507/935 Enhanced oil recovery
• CPC Class Codes: Y10S 524/915 Carpet backing adhesives
• CPC Class Codes: Y10S 524/916 Hydrogel compositions

Abstract

Cross-linked water-swellable polymers are described, having a particle size of less than 4 microns. They are used as thickening agents for aqueous dispersions or solutions, particularly useful where high shear conditions are encountered in the application.

Claims

1. A method for thickening an aqueous medium to obtain a composition having the properties of a viscous short solution and being resistant to viscosity degradation under conditions of high shear which comprises the step of thoroughly dispersing in said medium from about 0.1 to about 2 percent by weight of microbeads of a water-insoluble, water-swellable polymer of a water-soluble vinyl monomer or mixture of water-soluble vinyl monomers, cross-linked with a difunctional cross-linking agent copolymerizable with said monomer or monomers, said microbeads having diameters of from about 0.2 to about 4 microns and having a gel capacity of at least about 10 grams per gram in aqueous 0.27 molar sodium chloride solution, said cross-linking agent being present in an amount from about 50 to 1000 parts by weight of cross-linking agent per million parts of vinyl monomer or monomers in the polymer.

2. A method according to claim 1 wherein the polymer is cross-linked with from about 100 to 400 parts by weight of cross-linking agent per million parts of vinyl monomer or monomers in the polymer.

3. A method according to claim 2 wherein the vinyl monomer is acrylamide.

4. A method according to claim 2 wherein the polymer is a copolymer of acrylamide and acrylic acid with the cross-linking agent.

5. A method according to claim 2 wherein the polymer is a copolymer of acrylamide and sodium acrylate with the cross-linking agent.

6. The method of claim 1 wherein the cross-linking agent is divinylbenzenesulfonate, ethyleneglycol diacrylate, ethylene glycol dimethacrylate, propylene glycol diacrylate, allyl acrylae, diallyl ethylene glycol ether, divinyl ether, dially ether, divinyl ether of ethylene glycol, divinyl ether of diethylene glycol, divinyl ether of triethylene glycol, N,N'"'"'-methylene-bis-acrylamide, N,N'"'"'-methylene-bis-methacrylamide and other lower alkylidene-bis-acrylamides wherein the alkylidene group has up to 4 carbons.

7. The method of claim 1 wherein the vinyl monomer is proponderantly acrylamide and the cross-linking agent is N,N'"'"'-methylene-bis-acrylamide, N,N'"'"'-methylene-bis-methacrylamide and other lower alkylidene-bis-acrylamides wherein the alkylidene group has up to 4 carbons.

8. A viscous, short aqueous composition comprising an aqueous medium having dispersed therein from about 0.1 to about 2 percent by weight of microbeads of a water-insoluble, water-swellable polymer of a water-soluble vinyl monomer or mixture of water-soluble vinyl monomers, cross-linked with a difunctional cross-linking agent copolymerizable with said monomer or monomers, said microbeads having diameters of from about 0.2 to about 4 microns and having a gel capacity of at least about 10 grams per gram in aqueous 0.27 molar sodium chloride solution, said polymer being cross-linked with from about 50 to 1000 parts by weight of cross-linking agent per million parts of vinyl monomer or monomers in the polymer.

9. A composition according to claim 8 wherein the polymer is cross-linked with from about 100 to 400 parts by weight of cross-linking agent per million parts of vinyl monomer or monomers in the polymer.

10. A composition according to claim 9 wherein the vinyl monomer consists preponderantly of acrylamide.

11. A composition according to claim 10 wherein the polymer is a copolymer of acrylamide and acrylic acid with the cross-linking agent.

12. A composition according to claim 9 wherein the polymer is a copolymer of acrylamide and sodium acrylate with the cross-linking agent.

13. The composition according to claim 8 wherein the cross-linking agent is divinylbenzenesulfonate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, propylene glycol diacrylate, allyl acrylate, diallyl ethylene glycol ether, divinyl ether, diallyl ether, divinyl ether of ethylene glycol, divinyl ether of diethylene glycol, divinyl ether of triethylene glycol, N,N'"'"'-methylene-bis-acrylamide, N,N'"'"'-methylene-bis-methacrylamide and other lower alkylidene-bis-acrylamide wherein the alkylidene group has up to 4 carbons.

14. The composition of claim 8 wherein the the vinyl monomer is proponderantly acrylamide and the cross-linking agent is N,N'"'"'-methylene-bis-acrylamide, N,N'"'"'-methylene-bis-methacrylamide and other lower alkylidene-bis-acrylamides wherein the alkylidene group has up to 4 carbons.

15. An aqueous composition comprising an aqueous medium having dispersed therein microbeads of a water-insoluble water-swellable polymer of a water-soluble vinyl monomer or mixture of water-soluble vinyl monomers, cross-linked with from about 50 to 1000 parts by weight of a difunctional cross-linking agent per million parts of vinyl monomer or monomers in the polymer, said agent being copolymerizable with said monomer or monomers, said microbeads having a gel capacity at least 10 grams per gram in aqueous 0.27 molar sodium chloride solution diameters from about 0.2 to about 4 microns and being present in an amount sufficient to thicken the aqueous medium to a viscous, short aqueous composition.