Water-soluble copolymer film packet

• US 6,787,512 B1
• Filed: 11/26/2003
• Issued: 09/07/2004
• Est. Priority Date: 03/19/2003
• Status: Expired due to Term

• Current Assignee: Monosol LLC (Kuraray Company Limited), Sekisui Specialty Chemicals America, LLC (Sekisui)
• Original Assignee: Monosol LLC (Kuraray Company Limited)
• Inventors: Verrall, Andrew P., Kugler, Karen A., Bening, P. Scott
• Primary Examiner(s): OGDEN JR, NECHOLUS
• Application Number:
  US10/723,647
• Time in Patent Office: 286 Days
• Field of Search: 510/293, 510/295, 510/296, 510/297, 510/438, 428/35.2, 526/264, 526/330
• US Class Current: 510/293
• CPC Class Codes: C08F 218/08 Vinyl acetate
• CPC Class Codes: C08F 222/02 Acids; Metal salts or ammonium salts thereof , e.g. maleic acid or itaconic acid
• CPC Class Codes: C08F 2810/50 wherein the polymer is a copolymer and the modification is taking place only on one or more of the monomers present in minority
• CPC Class Codes: C08F 8/12 Hydrolysis
• CPC Class Codes: C08F 8/44 Preparation of metal salts or ammonium salts
• CPC Class Codes: C11D 17/043 Liquid or thixotropic (gel) compositions
• CPC Class Codes: Y10T 428/1334 Nonself-supporting tubular film or bag [e.g., pouch, envelope, packet, etc.]

Abstract

Generally speaking, the present invention is a water-soluble copolymer film comprising a hydrolyzed copolymer of vinyl acetate and a second monomer, the resultant polyvinyl alcohol copolymer having a degree of hydrolysis, expressed as a percentage of vinyl acetate units converted to vinyl alcohol units, of from about 90% to 100%. The second monomer is preferably selected from the group of monomers having carboxylate functionality or sulfonate functionality. The resulting water-soluble copolymer film is disclosed for use in making pouches to contain a unit dose of liquid detergent, such as a liquid laundry detergent. However, it is an aspect of the copolymer film that film solubility is not significantly affected adversely by the detergent. Such film produces pouches having a greater storage shelf-life over prior art water-soluble film.

Claims

1. A water-soluble packet comprising:

a copolymer film comprising;

a hydrolyzed copolymer of vinyl acetate and a second monomer, the resultant polyvinyl alcohol copolymer having a degree of hydrolysis, expressed as a percentage of vinyl acetate units converted to vinyl alcohol units, in the range of from about 90% to about 100%;

wherein the second monomer is selected from the group consisting of vinyl sulfonic acid monomers, alkali metal salts of sulfonic acid monomers, and combinations thereof; and

a quantity of liquid material contained within the packet in direct contact with said copolymer film.

2. The water-soluble packet of claim 1, wherein the liquid material comprises a cleaning concentrate.

3. The water-soluble packet of claim 2, wherein the cleaning concentrate comprises laundry detergent.

4. The water-soluble packet of claim 1, wherein the second monomer is selected from the group of sulfonic acid monomers consisting of vinyl sulfonic acid, allyl sulfonic acid, ethylene sulfonic acid, 2-acrylamido-1-methylpropanesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-methylacrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl acrylate, their alkali metal salts, and combinations of the foregoing.

5. The water-soluble packet of claim 4, wherein the second monomer is an alkali metal salt of 2-acrylamido-2-methylpropanesulfonic acid.

6. The water-soluble packet of claim 5, wherein the degree of polymerization of the copolymer is such that the viscosity of a 4% aqueous solution at 20°

C. is in a range of from about 3 to about 18 MPa.s (cps).

7. The water-soluble packet of claim 6, wherein the degree of polymerization of the copolymer is such that the viscosity of a 4% aqueous solution at 20°

C. is in a range of from about 4 to about 12 MPa.s.

8. The water-soluble packet of claim 5, wherein the level of incorporation of the second monomer in the copolymer, expressed as a mole percentage, is in the range of from about 1 to about 8 mole %.

9. The water-soluble packet of claim 8, wherein the level of incorporation of the second monomer in the copolymer, expressed as a mole percentage, is in the range of from about 2.5 to about 5 mole %.

18. The water-soluble packet of claim 5, wherein the second monomer is the sodium salt of 2-acrylamido-2-methylpropanesulfonic acid.

10. A water-soluble copolymer film comprising:

a hydrolyzed copolymer of vinyl acetate and a second monomer, the resultant polyvinyl alcohol copolymer having a degree of hydrolysis, expressed as a percentage of vinyl acetate units converted to vinyl alcohol units, of from about 90% to 100%;

an initial disintegration time at 10°

C. of less than 60 seconds; and

a disintegration time increase after contacting a liquid component contained therein of no more than 50%.

11. The water-soluble copolymer film of claim 10, wherein the second monomer is a monomer having a sulfonate functionality.

12. The water-soluble copolymer film of claim 11, wherein the second monomer is selected from the group consisting of vinyl sulfonic acid monomers, alkali metal salts of vinyl sulfonic acid monomers, and combinations thereof.

13. The water-soluble copolymer film of claim 12, wherein the second monomer comprises an alkali metal salt of 2-acrylamido-2-methylpropanesulfonic acid.

14. The water-soluble film of claim 13, wherein the degree of polymerization of the copolymer is such that the viscosity of a 4% aqueous solution at 20°

C. is in a range of from about 3 to about 18 MPa.s (cps).

15. The water-soluble film of claim 14, wherein the degree of polymerization of the copolymer is such that the viscosity of a 4% aqueous solution at 20°

C. is in a range of from about 4 to about 12 MPa.s.

16. The water-soluble film of claim 10, in the form of a film packet surrounding a contained liquid component, wherein the liquid component contained therein comprises a cleaning concentrate.

17. The water-soluble packet of claim 16, wherein the cleaning concentrate comprises laundry detergent.

19. The water-soluble packet of claim 13, wherein the second monomer is the sodium salt of 2-acrylamido-2-methylpropanesulfonic acid.