Polyglycolic acid resin composition, molded product for well drilling, and downhole tool member

Patent metadata

Field	Value
Publication number	US-2018094132-A1
Application number	US-201715831958-A
Country	US
Kind code	A1
Filing date	Dec 5, 2017
Priority date	Nov 13, 2014
Publication date	Apr 5, 2018
Grant date	—

Abstract

In light of increasingly severe and diverse excavation conditions for hydrocarbon resource recovery, such as the drilling of very deep wells, provided is a highly impact-resistant polyglycolic acid resin composition that is resistant to damage even from contact or collision with various members during molding, transport, and well drilling; has excellent mechanical properties and heat resistance; can easily be removed as necessary after the completion of well treatment; and contributes to reducing the cost and shortening the process of well drilling. Also, provided is a molded product for well drilling, such as a downhole tool member.

First claim

1 . A molded product for well drilling formed from a polyglycolic acid resin composition,
the polyglycolic acid resin composition comprising:
a polyglycolic acid; and
an acrylic rubber core-shell polymer having an acrylic rubber as a core layer, and a vinyl (co)polymer as a shell layer,
wherein a melt viscosity of the polyglycolic acid is from 450 to 1600 Pa·s when measured at a temperature of 270° C. and a shear rate of 122 sec −1 , an average inter-particle distance of the acrylic rubber core-shell polymer dispersed in the polyglycolic acid is from 0.2 to 2.5 μm, an Izod impact strength (unnotched) of the polyglycolic acid resin composition after being left to stand for 4 hours at a temperature of 170° C. is 70% or greater of that of the polyglycolic acid resin composition prior to being left to stand for 4 hours at the temperature of 170° C., the Izod impact strength being measured in accordance with ASTM D256, and the molded product for well drilling is a downhole tool member.

2 . The molded product for well drilling according to claim 1 , wherein the polyglycolic acid resin composition further comprises from 60 to 98 mass % of the polyglycolic acid and from 2 to 40 mass % of the acrylic rubber core-shell polymer, where a total of the polyglycolic acid and the acrylic rubber core-shell polymer equals 100 mass %.

3 . The molded product for well drilling according to claim 1 , wherein the polyglycolic acid resin composition further comprises from 1 to 25 parts by mass of a glycidyl methacrylate-ethylene copolymer, where the total of the polyglycolic acid and the acrylic rubber core-shell polymer equals 100 parts by mass.

4 . The molded product for well drilling according to claim 1 , wherein the molded product for well drilling is a melt molded product.

5 . The molded product for well drilling according to claim 1 , wherein the downhole tool member is selected from the group consisting of balls, ball seats, mandrels, slips, wedges, and rings.

6 . A well drilling method using the molded product for well drilling according to claim 1 .

Assignees

• Kureha Corp

Inventors

• Kobayashi Takuma
• Saijo Hikaru
• Yoshida Katsumi

Classifications

• C08L67/04 Primary

  Polyesters derived from hydroxycarboxylic acids, e.g. lactones (C08L67/06 takes precedence) · CPC title

• C08G63/06

  derived from hydroxycarboxylic acids · CPC title

• C08L23/08

  Copolymers of ethene (C08L23/16 takes precedence) · CPC title

• B22C1/2266

  Polyesters; Polycarbonates · CPC title

• C08L33/10

  Homopolymers or copolymers of methacrylic acid esters · CPC title