Water-soluble film and package

Patent metadata

Field	Value
Publication number	US-12275827-B2
Application number	US-202117360004-A
Country	US
Kind code	B2
Filing date	Jun 28, 2021
Priority date	Dec 28, 2018
Publication date	Apr 15, 2025
Grant date	Apr 15, 2025

Abstract

Provided are a water-soluble film capable of inhibiting sticking between the films while maintaining excellent water solubility and a package using the same. A water-soluble film of the present invention includes a polyvinyl alcohol resin. When a crystallinity index calculated using a diamond prism is Fd1 and a crystallinity index calculated using a germanium prism is Fg1 for FT-IR measurement of a first surface of the water-soluble film by ATR technique, Fd1 and Fg1 are Fd1≤0.65 and Fd1/Fg1<1. Fd1 is preferably Fd1≥0.25.

First claim

The invention claimed is:

1. A water-soluble film comprising a polyvinyl alcohol resin having: (i) a degree of saponification of 64 to 93 mol %, and (ii) a degree of polymerization of 200 to 8000,wherein,
a complete dissolution time of the water-soluble film is 90 seconds or less, and
when a crystallinity index calculated using a diamond prism is Fd 1 and a crystallinity index calculated using a germanium prism is Fg1 for FT-IR measurement of a first surface of the water-soluble film by ATR technique,
the Fd1 and the Fg1 satisfy formulae below:
Fd1≤0.65   (1)

Fd1/Fg1<1   (2).

2. The water-soluble film according to claim 1 , wherein the Fd1 satisfies a formula below:
Fd1≥0.25   (3).

3. The water-soluble film according to claim 1 , wherein the Fd1 and the Fg1 satisfy a formula below:
Fd1/Fg1≥0.5   (4).

4. The water-soluble film according to claim 1 , wherein,
when a crystallinity index calculated using a diamond prism is Fd2 and a crystallinity index calculated using a germanium prism is Fg2 for FT-IR measurement of a second surface opposed to the first surface of the water-soluble film by the ATR technique,
the Fd2 and the Fg2 satisfy formulae below:
Fd2≤0.65   (5)

Fd2/Fg2<1   (6).

5. The water-soluble film according to claim 4 , wherein the Fd2 satisfies a formula below:
Fd2≥0.25   (7).

6. The water-soluble film according to claim 4 , wherein the Fd2 and the Fg2 satisfy a formula below:
Fd2/Fg2<0.5   (8).

7. The water-soluble film according to claim 4 , wherein the Fd1 and the Fd2 satisfy a formula below:
|Fd1−Fd2|0.07   (9).

8. The water-soluble film according to claim 4 , wherein the Fg1 and the Fg2 satisfy a formula below:
|Fg1−Fg2|≤0.07   (10).

9. A package comprising: a packaging material composed of the water-soluble film according to claim 1 and a chemical encapsulated in the packaging material.

10. The package according to claim 9 , wherein the chemical is a pesticide, a detergent, or a germicide.

11. The package according to claim 9 , wherein the chemical is in a liquid form.

12. The water-soluble film according to claim 1 , wherein the polyvinyl alcohol resin has the degree of polymerization of 200 to 300 or the degree of saponification of 64 to 88mol %.

13. The water-soluble film according to claim 1 , wherein the polyvinyl alcohol resin includes at least one selected from unmodified polyvinyl alcohol, an acrylamide-2-methylpropanesulfonic acid sodium salt (AMPS) modified polyvinyl alcohol, and a maleic acid monomethyl ester (MMM) modified polyvinyl alcohol.

14. The water-soluble film according to claim 1 , wherein the water-soluble film comprises a single polyvinyl alcohol resin or two or more polyvinyl alcohol resins having a degree of polymerization, a degree of saponification, and/or a degree of modification different from each other.

15. The water-soluble film according to claim 1 , wherein the complete dissolution time of the water-soluble film is measured in deionized water at 10° C., and the water-soluble film is formed by a process that includes discharging a film forming stock solution including the polyvinyl alcohol resin on a drying roll having a surface temperature of 40° C. to 110° C. to form a dried film, and the film forming stock solution is discharged from a T die.

16. The water-soluble film according to claim 15 , wherein the process further includes blowing air at a temperature of 50° C. to 120° C. and at a wind velocity of 1 to 10 m/second during the discharging.

17. The water-soluble film according to claim 15 , wherein the process excludes a heat treatment after the discharging.

18. The water-soluble film according to claim 15 , wherein the process further includes, after the discharging, heat treating the dried film at a temperature of 60° C. or more and less than 130° C.

19. The water-soluble film according to claim 1 , further comprising glycerin.

20. The water-soluble film according to claim 1 , wherein the polyvinyl alcohol resin is an unmodified polyvinyl alcohol resin.

Assignees

• Kuraray Co

Inventors

• Okamoto Minoru
• Shimizu Sayaka
• Kazeto Osamu

Classifications

• C11D17/043

  Liquid or thixotropic (gel) compositions · CPC title

• C08L2203/16

  used for films · CPC title

• C08L29/04

  Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids · CPC title

• C08J2329/04

  Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids · CPC title

• A01N25/34

  Shaped forms, e.g. sheets, not provided for in any other sub-group of this main group · CPC title