# US 11,439,582 B2 · Low-stringiness thickener and cosmetic material admixed with said thickener

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- Number: US 11,439,582 B2
- Document ID: US11439582B2
- Status: Granted
- Kind: B2
- Application number: 15/784,337
- Filed: 2017-10-16
- Published: 2018-02-08
- Granted: 2022-09-13
- Earliest claimed: 2017-10-16
- Assignees: Shiseido Company, Ltd.
- Applicants: Shiseido Company, Ltd.
- Inventors: Atsushi Sogabe; Ayano Matsuo; Shin-Ichi Yusa
- Web page: https://patentgrep.com/patent/US11439582B2

## CPC

- A61K 8/8147: {Homopolymers or copolymers of acids; Metal or ammonium salts thereof, e.g. crotonic acid, (meth)acrylic acid; Compositions of derivatives of such polymers}
- A61K 8/8152: {Homopolymers or copolymers of esters, e.g. (meth)acrylic acid esters; Compositions of derivatives of such polymers}
- A61K 8/8158: {Homopolymers or copolymers of amides or imides, e.g. (meth) acrylamide; Compositions of derivatives of such polymers}
- A61Q 19/00: Preparations for care of the skin
- C08F 8/44: Preparation of metal salts or ammonium salts
- C08F 120/06: Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
- C08F 120/58: containing oxygen in addition to the carbonamido oxygen {, e.g. N-methylolacrylamide, N-acryloyl morpholine}
- A61K 2800/10: General cosmetic use
- A61K 2800/48: Thickener, Thickening system
- 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)
- A61Q: SPECIFIC USE OF COSMETICS OR SIMILAR TOILETRY PREPARATIONS
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS

## Abstract

Aqueous compositions can be thickened without increasing stringiness, by using polymers of polyacrylic acid, poly(2-acryamide-2-methylpropanesulfonate), or salts thereof, having a weight average molecular weights of 500,000 to 8,000,000 as thickeners. The polymers contain no more than 10 mass % of polymers having a molecular weight of 10,000,00 or more, and/or contain no more than 10 mass % of polymers having more than three times the weight average molecular weight. Aqueous solutions of these polymers exhibit a low degree of stringiness, and are particularly useful as thickeners for cosmetics.

## Claims

### Claim 1

A method of increasing the viscosity of a cosmetic without increasing the stringiness of the cosmetic, comprising thickening said cosmetic by adding an effective viscosity-increasing amount of a polymer selected from the group consisting of polyacrylic acid and salts thereof, wherein:
(a)
(b) the polymer is selected from the group consisting of RAFT polymers having a weight average molecular weight between 500 thousand and 8 million;
(c) not more than 10% by mass of said RAFT polymer consists of molecules having a molecular weight of 10 million or higher;
(d) the measured stringiness of a 1% w/w aqueous solution of the RAFT polymer is 10 mm or less; and
(e) the amount of RAFT polymer is between 0.05 and 2.5 mass % relative to the mass of the cosmetic.

### Claim 2

A method of increasing the viscosity of a cosmetic without increasing the stringiness of the cosmetic, comprising thickening said cosmetic by adding an effective viscosity-increasing amount of a polymer selected from the group consisting of polyacrylic acid and salts thereof, wherein:
(a) ;
(b) the polymer is selected from the group consisting of RAFT polymers having a weight average molecular weight between 500 thousand and 8 million;
(c) not more than 10% by mass of said RAFT polymer consists of molecules having a molecular weight that is more than three times the weight average molecular weight of said RAFT polymer;
(d) the measured stringiness of a 1% w/w aqueous solution of the RAFT polymer is 10 mm or less; and
(e) the amount of RAFT polymer is between 0.05 and 2.5 mass % relative to the mass of the cosmetic.

### Claim 3 (depends on 1)

The method of claim 1, wherein the weight-average molecular weight of said polymer is between 2.24 million and 8 million.

### Claim 4 (depends on 2)

The method of claim 2, wherein the weight-average molecular weight of said polymer is between 2.24 million and 8 million.

### Claim 5 (depends on 1)

The method of claim 1, wherein the weight-average molecular weight of said polymer is between 4.03 million and 8 million.

### Claim 6 (depends on 2)

The method of claim 2, wherein the weight-average molecular weight of said polymer is between 4.03 million and 8 million.

### Claim 7 (depends on 1)

The method of claim 1, wherein the weight-average molecular weight of said polymer is between 6.21 million and 8 million.

### Claim 8 (depends on 2)

The method of claim 2, wherein the weight-average molecular weight of said polymer is between 6.21 million and 8 million.