# US 5,346,542 A · Aqueous dispersion of enteric polymers and a method for producing the same

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- Number: US 5,346,542 A
- Document ID: US5346542A
- Status: Granted
- Kind: A
- Application number: 07/973,125
- Filed: 1992-11-06
- Granted: 1994-09-13
- Earliest claimed: 1991-11-06
- Assignees: Asahi Kasei Kogyo Kabushiki Kaisha
- Inventors: Honda Yosuke; Tanabe Tsuneaki; Yaginuma Yoshihito
- Web page: https://patentgrep.com/patent/US5346542A

## CPC

- A61K 9/5047: {Cellulose ethers containing no ester groups, e.g. hydroxypropyl methylcellulose}
- A23P 20/105: {Coating with compositions containing vegetable or microbial fermentation gums, e.g. cellulose or derivatives; Coating with edible polymers, e.g. polyvinyalcohol}
- A61K 9/2866: {Cellulose; Cellulose derivatives, e.g. hydroxypropyl methylcellulose}
- A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D)
- A23P: SHAPING OR WORKING OF FOODSTUFFS, NOT FULLY COVERED BY A SINGLE OTHER SUBCLASS

## Abstract

A novel polymer aqueous dispersion of enteric cellulose derivatives without ester bonded substituents, of which anionic functional groups form salts with cations. The aqueous dispersion of the present invention is used as coating agents for foods and pharmaceuticals. It has high dispersion stability such as high mechanical stability and high storage stability.

## Claims

### Claim 1

A latex of enteric polymers, which comprises:
i) water and
ii) enteric cellulose derivatives without ester-bonded substituents, the cellulose derivatives have anionic functional groups wherein from 0.5 to 60 mole % of the anionic functional groups are forming nontoxic salts with at least one cation selected from the group consisting of magnesium ion, calcium ion, barium ion and aluminum ion and the cellulose derivatives are globular solid particles With a diameter of 20 .mu.m and below.

### Claim 2

A latex of enteric polymers, which comprises:
i) water,
ii) enteric cellulose derivatives without ester-bonded substituents, and
iii) at least one additive selected from a plasticizer, an anti-foaming agent, a suspension agent and an emulsifier, the cellulose derivatives have anionic functional groups wherein from 0.5 to 60 mole % of the anionic functional groups is forming nontoxic salts with at least one cation selected from the group consisting of magnesium ion, calcium ion, barium ion and aluminum ion and the cellulose derivatives are globular solid particles with a diameter of 20 .mu.m and below.

### Claim 3 (depends on 1, 2)

The latex according to claims 1 or 2, wherein the cellulose derivative is carboxymethylethyl cellulose.

### Claim 4 (depends on 2)

The latex according to claim 2, wherein the emulsifier is not contained in the latex.

### Claim 5 (depends on 1, 2)

The latex according to claims 1 or 2, wherein concentration of solids of the cellulose derivatives is from 5 to 40% by weight based on the latex.

### Claim 6

A method for producing a latex of enteric cellulose derivatives without ester-bonded substituents, which comprises the following steps of:
i) dissolving the cellulose derivatives with anionic functional groups in an solvent which is substantially water immiscible to get a solution,
ii) dispersing the solution with water in the presence of at least one alkali selected from the group consisting of magnesium hydroxide, calcium hydroxide, barium hydroxide and aluminum hydroxide to form nontoxic salts with from 0.5 to 60 mole % of the anionic functional groups of the cellulose derivatives to obtain a dispersion, and
iii) removing the organic solvent from the dispersion.

### Claim 7 (depends on 6)

The method according to claim 6, wherein the cellulose derivatives in the dispersion are globular solid particles with a diameter of 20 .mu.m and below.

### Claim 8 (depends on 6)

The method according to claim 6, wherein a continuous phase of the enteric cellulose derivatives and the organic solvent and a dispersion phase of water are inverted by removing the organic solvent from the dispersion.

### Claim 9 (depends on 6)

The method according to claim 6, wherein the cellulose derivative is carboxymethylethy cellulose.