Method for producing acrylic block copolymer pellets

Patent metadata

Field	Value
Publication number	US-12006406-B2
Application number	US-201916973924-A
Country	US
Kind code	B2
Filing date	May 28, 2019
Priority date	Jun 12, 2018
Publication date	Jun 11, 2024
Grant date	Jun 11, 2024

Abstract

Pellets of an acrylic block copolymer are provided which are imparted with sufficient antiblocking properties without deterioration in the outstanding performance of the acrylic block copolymer such as transparency. A method for producing pellets (D) including an acrylic block copolymer (A) includes bringing raw pellets of an acrylic block copolymer (A) into contact with an aqueous dispersion (C) containing acrylic resin particles (B) and no surfactants, the acrylic block copolymer (A) including at least one polymer block (a1) including acrylic acid alkyl ester units and at least one polymer block (a2) including methacrylic acid alkyl ester units, and removing water attached to the pellets.

First claim

The invention claimed is:

1. A method for producing pellets (D) including an acrylic block copolymer (A), the method comprising:
dry grinding and wet grinding an acrylic resin to produce acrylic resin particles (B);
contacting raw pellets of an acrylic block copolymer (A) with an aqueous dispersion (C) comprising acrylic resin particles (B) and no surfactants, the acrylic block copolymer (A) comprising a polymer block (a1) comprising acrylic acid alkyl ester units and a polymer block (a2) comprising methacrylic acid alkyl ester units; and
removing water attached to the pellets.

2. The method of claim 1 , wherein the acrylic resin particles (B) in the aqueous dispersion (C) comprise not less than 85 mass % of methyl methacrylate units.

3. The method of claim 1 , wherein the acrylic resin particles (B) in the aqueous dispersion (C) have a D50 value in a particle size distribution of from 1 to 50 μm.

4. The method of claim 1 , wherein the solid concentration of the acrylic resin particles (B) in the aqueous dispersion (C) is in a range of from 0.05 to 2.0 mass %.

5. The method of claim 1 , wherein, in the contacting, the raw pellets of the acrylic block copolymer (A) are brought into contact with the aqueous dispersion (C) having a temperature in a range of from 10 to 80° C.

6. The method of claim 1 , wherein the acrylic block copolymer (A) comprises, in the molecule thereof, a structure in which a polymer block (a2) comprising methacrylic acid alkyl ester units is bonded to each of both ends of a polymer block (a1) comprising acrylic acid alkyl ester units, and
wherein the acrylic block copolymer (A) has a weight average molecular weight in a range of from 30,000 to 250,000 and a content of the polymer blocks (a2) in a range of from 5 to 40 mass %.

Assignees

• Kuraray Co

Inventors

• Akai Makoto
• Ono Tomohiro
• Kawahara Moe

Classifications

• C08F220/18

  with acrylic or methacrylic acids · CPC title

• C08F220/14

  Methyl esters {, e.g. methyl (meth)acrylate} · CPC title

• C08J2355/00

  Characterised by the use of homopolymers or copolymers, obtained by polymerisation reactions only involving carbon-to-carbon unsaturated bonds, not provided for in groups C08J2323/00 - C08J2353/00 · CPC title

• C08F293/00

  Macromolecular compounds obtained by polymerisation on to a macromolecule having groups capable of inducing the formation of new polymer chains bound exclusively at one or both ends of the starting macromolecule (on to polymers modified by introduction of unsaturated end groups C08F290/02) · CPC title

• C08L33/12

  Homopolymers or copolymers of methyl methacrylate · CPC title