Method for producing latex and method for producing hollow resin particles

Patent metadata

Field	Value
Publication number	US-11760857-B2
Application number	US-201816634233-A
Country	US
Kind code	B2
Filing date	Jul 31, 2018
Priority date	Aug 1, 2017
Publication date	Sep 19, 2023
Grant date	Sep 19, 2023

Abstract

Provided is a method for producing a latex comprising hollow resin particles each with a high void ratio and a method for producing hollow resin particles each with a higher void ratio. In the method for producing the latex: a suspension treatment of the mixture liquid which comprises a monomer, a crosslinkable monomer, an oil-soluble polymerization initiator, a fat/fatty oil, a hydrocarbon solvent, a suspension stabilizer and an aqueous medium is carried out to prepare a suspension comprising monomer drops; a polymerization reaction of the suspension is carried out to prepare a precursor composition which comprises precursor particles each having a hollow portion including the hydrocarbon solvent.

First claim

The invention claimed is:

1. A method for producing a latex comprising latex particles each having a hollow portion, the method comprising steps of:
preparing a mixture liquid comprising (A) at least one monomer selected from the group consisting of a monovinyl monomer and a hydrophilic monomer, (B) a crosslinkable monomer, (C) an oil-soluble polymerization initiator, (D) a fat/fatty oil, (E) a hydrocarbon solvent, (F) a suspension stabilizer and (G) an aqueous medium;
carrying out a suspension treatment of the mixture liquid to prepare a suspension which comprises monomer drops comprising the hydrocarbon solvent dispersed in the aqueous medium;
carrying out a polymerization reaction of the suspension to prepare a precursor composition comprising precursor particles each having a hollow portion including the hydrocarbon solvent;
adding a base to the precursor composition to set a pH of the precursor composition at 6.0 or more; and,
removing the hydrocarbon solvent included in the precursor particles in the precursor composition to obtain the latex comprising the latex particles each having the hollow portion.

2. The method according to claim 1 , wherein the at least one monovinyl monomer and the at least one hydrophilic monomer are used in combination with each other.

3. The method according to claim 2 , wherein an amount ratio of the at least one hydrophilic monomer is from 10% to 50% by mass provided that a total amount of the at least one monovinyl monomer and the at least one hydrophilic monomer is regarded as 100% by mass.

4. The method according to claim 1 , wherein a number average particle diameter of the latex particles included in the obtained latex is from 0.1 μm to 10 μm.

5. The method according to claim 1 , wherein a void ratio of the latex particles included in the obtained latex is 70% to 99%.

6. A method for producing hollow resin particles, the method comprising steps of:
preparing a mixture liquid comprising (A) a monomer comprising at least one acrylic-based hydrophilic monomer selected from the group consisting of acrylic acid and methacrylic acid, the acrylic-based hydrophilic monomer excluding acrylonitrile and methacrylonitrile, or a monomer comprising a combination of at least one acrylic-based monovinyl monomer selected from the group consisting of acrylate and methacrylate, the acrylic-based monovinyl monomer excluding a hydrophilic monomer selected from the group consisting of monomers having an ethylenically unsaturated bond and a hydrophilic group, and at least one acrylic-based hydrophilic monomer selected from the group consisting of acrylic acid and methacrylic acid, the acrylic-based hydrophilic monomer excluding acrylonitrile and methacrylonitrile (B) a crosslinkable monomer, (C) an oil-soluble polymerization initiator, (E) a hydrocarbon solvent, (F) a suspension stabilizer and (G) an aqueous medium, wherein a mass ratio of the acrylic-based hydrophilic monomer to the acrylic-based monovinyl monomer in the monomer (A) represented by “[the acrylic-based hydrophilic monomer]:[the acrylic-based monovinyl monomer]” is from 100:0 to 20:80, and wherein an amount of the contained crosslinkable monomer (B) is from 25 parts by mass to 59 parts by mass provided that a total amount of the monomer (A) and the crosslinkable monomer (B) is regarded as 100 parts by mass;
carrying out a suspension treatment of the mixture liquid to prepare a suspension which comprises monomer drops comprising the hydrocarbon solvent (E) dispersed in the aqueous medium;
carrying out a polymerization reaction of the suspension to prepare a precursor composition comprising precursor particles each having a hollow portion including the hydrocarbon solvent;
carrying out a solid-liquid separation of the precursor composition to obtain the precursor particles; and,
removing the hydrocarbon solvent included in the precursor particles in a gaseous atmosphere to obtain the hollow resin particles.

7. The method according to claim 6 , wherein a method for solid-liquid separation of the precursor composition is centrifugation or filtration.

8. The method according to claim 6 , wherein the step of preparing the mixture liquid is a step of mixing an oil phase comprising the monomer (A), the crosslinkable monomer (B), the oil-soluble polymerization initiator (C), and the hydrocarbon solvent (E), wherein a mass ratio of the acrylic-based hydrophilic monomer to the acrylic-based monovinyl monomer in the monomer (A) represented by “[the acrylic-based hydrophilic monomer]:[the acrylic-based monovinyl monomer]” is from 100:0 to 20:80, and wherein an amount of the contained crosslinkable monomer (B) is from 25 parts by mass to 59 parts by mass provided that a total amount of the monomer (A) and the crosslinkable monomer (B) is regarded as 100 parts by mass, with an aqueous phase comprising the suspension stabilizer (F) and the aqueous medium (G).

9. The method according to claim 6 , wherein a relative permittivity of the hydrocarbon solvent (E) is 3 or less at 20° C.

10. The method according to claim 6 , wherein the hydrocarbon solvent (E) is a hydrocarbon compound having 5 to 7 carbon atoms.

11. The method according to claim 6 , wherein an amount of the hydrocarbon solvent (E) is 200 parts by mass or more provided that a total amount of the monomer (A) and the crosslinkable monomer (B) is regarded as 100 parts by mass.

12. The method according to claim 6 , wherein a number average particle diameter of the obtained hollow resin particles is from 0.1 μm to 10 μm.

13. The method according to claim 6 , wherein a void ratio of the obtained hollow resin particles is from 70% to 99%.

Assignees

• Zeon Corp

Inventors

• Iga Takashi
• Hirata Takeshi
• Yabuki Nozomi

Classifications

• C08F2/18 Primary

  Suspension polymerisation · CPC title

• C08J9/20 Primary

  by suspension polymerisation in the presence of the blowing agent · CPC title

• C08F2/32

  Polymerisation in water-in-oil emulsions · CPC title

• C08F6/005

  from solid polymers · CPC title

• B01J13/14

  Polymerisation; cross-linking · CPC title