# US 8,541,490 B2 · Aliphatic polyester resin composition and process for production thereof

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 8,541,490 B2
- Document ID: US8541490B2
- Status: Granted
- Kind: B2
- Application number: 13/442,948
- Filed: 2012-04-10
- Published: 2012-10-11
- Granted: 2013-09-24
- Earliest claimed: 2011-04-11
- Assignees: Kureha Corporation
- Applicants: Fumio Akutsu; Naoki Hayashi; Hiroyuki Sato; Masumi Shibata; Akiko Watanabe
- Inventors: Fumio Akutsu; Naoki Hayashi; Hiroyuki Sato; Masumi Shibata; Akiko Watanabe
- Web page: https://patentgrep.com/patent/US8541490B2

## CPC

- C08J 3/203: {Solid polymers with solid and/or liquid additives}
- C08J 3/201: {Pre-melted polymers}
- C08K 5/521: Esters of phosphoric acids, e.g. of H3PO4
- C08J 2367/04: Polyesters derived from hydroxy carboxylic acids, e.g. lactones (C08J2367/06 takes precedence)
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)

## Abstract

A process for producing an aliphatic polyester resin composition, wherein an aliphatic polyester resin is melt-kneaded with a phosphoric acid ester having a reduced moisture content of 1.5 wt. % or less. As a result, an aliphatic polyester resin composition having an improved moisture resistance is provided.

## Claims

### Claim 1

A process for producing an aliphatic polyester resin composition, comprising the steps of:
drying a phosphoric acid ester with a particle diameter of at most 3.0 mm with dry gas set to a temperature equal to or lower than a melting point of the phosphoric acid ester to a reduced moisture content of 0.7 wt. % or less; and
melt-kneading an aliphatic polyester resin with the dried phosphoric acid ester.

### Claim 2 (depends on 1)

The process according to claim 1, wherein 0.003-3 wt parts of the phosphoric acid ester is melt-kneaded per 100 wt. parts of the aliphatic polyester resin.

### Claim 3 (depends on 1)

The process according to claim 1, wherein the phosphoric acid ester is a phosphoric acid ester having a hydroxyl group and a long-chain alkyl ester group, or a pentaerythritol skeleton.

### Claim 4 (depends on 1)

The process according to claim 1, wherein the aliphatic polyester resin is melt-kneaded with a carboxyl group-capping agent in a proportion of 0.01-10 wt. parts, per 100 wt. parts of the aliphatic polyester resin, in addition to the phosphoric acid ester.

### Claim 5 (depends on 1)

The process according to claim 1, wherein the aliphatic polyester resin is a polyglycolic acid resin.

### Claim 6 (depends on 1)

An aliphatic polyester resin composition produced by the process according to claim 1, having a molecular weight retention time down to a weight-average molecular weight (Mw)=7×104 of 120 hours or more in an environment of 50° C. and 90% RH.

### Claim 7 (depends on 6)

The aliphatic polyester resin composition according to claim 6, wherein the aliphatic polyester resin is a polyglycolic acid resin.