Kureha Corporation

Shunsuke Abe

Masahiro Yamazaki

Hiroyuki Sato

Kotaku Saigusa

Kenichi Suzuki

Takeo Takahashi

Hisaaki Terashima

Nanako Kuruhara

Provided is a well-treatment fluid that reduces a load on the environment. A well-treatment fluid containing a non-ionic polyamino acid derivative including an &#x3b1;-type or &#x3b2;-type polyaspartic acid monomer unit represented by Formula (I) and an &#x3b1;-type or &#x3b2;-type polyaspartic acid monomer unit represented by Formula (II). 

Well-treatment fluid, method for forming fracture, and method for isolating wellbore

Polyglycolic acid resin short fibers for a well treatment fluid, the fibers having the following characteristics of (a) to (e): (a) an outside diameter of 5 to 300 &#x3bc;m; (b) a fiber length of 1 to 30 mm; (c) fineness of 0.1 to 25 D; (d) strength of 1 to 20 gf/D; and (e) a ratio of an area of the polyglycolic acid resin with respect to an area of a circle circumscribing a cross section of the fibers being from 10 to 95%; and a well treatment fluid containing the polyglycolic acid resin short fibers for a well treatment fluid.

Polyglycolic acid resin short fibers for use in well treatment fluid

A method for producing an undrawn polyglycolic acid-based resin yarn, including: a discharge step of discharging a molten polyglycolic acid-based resin through a spinneret, to thereby form a fibrous polyglycolic acid-based resin; a keeping step of keeping the fibrous polyglycolic acid-based resin for 0.0012 seconds or more after the discharge in an atmosphere having a temperature of not lower than 110.5&#xb0; C. but not higher than a melting point of the polyglycolic acid-based resin; and a cooling step of cooling the fibrous polyglycolic acid-based resin obtained in the keeping step, to thereby obtain an undrawn polyglycolic acid-based resin yarn.

Method for producing polyglycolic acid resin yarn

Biodegradable aliphatic polyester particles have: (A) an average particle diameter of 10 to 500 &#x3bc;m, and (B) a quantity of heat of low-temperature crystallization calculated as an exotherm attending on crystallization, detected in the course of heating by DSC, of at least 1 J/g, and preferably: (C) a quantity of heat of crystal melting calculated as an endotherm attending on melting of a crystal, detected in the course of the heating, of less than 100 J/g, and (D) a difference between the quantity of heat of crystal melting and the quantity of heat of low-temperature crystallization of less than 90 J/g. A process for producing the particles comprises grinding a particular biodegradable aliphatic polyester having a weight average molecular weight of at least 50,000 at not lower than 0&#xb0; C. and lower than the glass transition temperature of the polyester while applying high shearing force.

Growing community of inventors

Tokyo, Japan

Shunsuke Abe