Polymer microparticles and method for producing same

Patent metadata

Field	Value
Publication number	US-2017298205-A1
Application number	US-201515511978-A
Country	US
Kind code	A1
Filing date	Sep 16, 2015
Priority date	Sep 18, 2014
Publication date	Oct 19, 2017
Grant date	—

Abstract

The present disclosure relates to a method for producing polymer microparticles, this method including a step for polymerizing vinyl monomers in a hydrophilic solvent, which dissolves the vinyl monomers and a dispersion stabilizer but does not dissolve a polymer formed, in the presence of the dispersion stabilizer. The present disclosure is a method for producing these polymer microparticles, wherein the dispersion stabilizer contains a macromonomer having carboxyl groups and ethylenically unsaturated groups at an intermediate location in a molecular chain thereof, the macromonomer has, on average, 1.4 to 2.5 ethylenically unsaturated groups per molecule, and an average value of a carboxyl group content in the macromonomer is 0.5 meq/g to 2.5 meq/g.

First claim

1 . A method for producing polymer microparticles,
the method comprising: producing the polymer microparticles by polymerizing vinyl monomers in a hydrophilic solvent, which dissolves the vinyl monomers and a dispersion stabilizer but does not dissolve a polymer formed, in the presence of the dispersion stabilizer; wherein the dispersion stabilizer contains a macromonomer having carboxyl groups and ethylenically unsaturated groups at an intermediate location in a molecular chain thereof, the macromonomer has, on average, 1.4 to 2.5 ethylenically unsaturated groups per molecule, and an average value of a carboxyl group content in the macromonomer is 0.5 meq/g to 2.5 meq/g.

2 . The method for producing polymer microparticles according to claim 1 , wherein the macromonomer contains a (meth)acryloyl group.

3 . The method for producing polymer microparticles according to claim 1 , wherein the number average molecular weight (Mn) of the macromonomer is 1000 g/mol to 10000 g/mol.

4 . The method for producing polymer microparticles according to claim 1 , wherein a value (Mw/Mn) obtained by dividing a weight average molecular weight (Mw) by the number average molecular weight (Mn) of the macromonomer is 2.3 or less.

5 . A polymer microparticle obtained with the production method according to claim 1 , wherein
a volume average particle diameter thereof is 0.7 μm to 3.0 μm, a value of volume average particle diameter (dv)/number average particle diameter (dn) is 1.2 or less, and the number of byproduct small particles per 1000 polymer microparticles each having a particle diameter of 0.1 μm or more is 500 or less.

6 . A polymer microparticle, which retains a macromonomer having carboxyl groups and ethylenically unsaturated groups at an intermediate location in a molecular chain thereof, wherein
the macromonomer has, on average, 1.4 to 2.5 ethylenically unsaturated groups per molecule, and an average value of a carboxyl group content in the macromonomer is 0.5 meq/g to 2.5 meq/g.

7 . The polymer microparticle according to claim 6 , wherein the volume average particle diameter is 0.7 μm to 3.0 μm, a value of volume average particle diameter (dv)/number average particle diameter (dn) is 1.2 or less, and the number of byproduct small particles per 1000 polymer microparticles each having a particle diameter of 0.1 μm or more is 500 or less.

8 . The polymer microparticle according to claim 6 , wherein the macromonomer is provided with the ethylenically unsaturated groups through a portion of the carboxyl groups at an intermediate location of the molecular chain thereof.

9 . A dispersion stabilizer used to produce polymer microparticles,
the dispersion stabilizer containing a macromonomer having carboxyl groups and ethylenically unsaturated groups at an intermediate location of the molecular chain thereof, wherein the macromonomer has, on average, 1.4 to 2.5 ethylenically unsaturated groups per molecule, and an average value of a carboxyl group content in the macromonomer is 0.5 meq/g to 2.5 meq/g.

10 . A method for dispersing polymer microparticles,
the method comprising:
dispersing a polymer in the form of microparticles by polymerizing vinyl monomers in the presence of the dispersion stabilizer according to claim 9 in a hydrophilic solvent that dissolves the vinyl monomers and the dispersion stabilizer but does not dissolve the polymer formed.

11 . The method for producing polymer microparticles according to claim 2 , wherein the number average molecular weight (Mn) of the macromonomer is 1000 g/mol to 10000 g/mol.

12 . The method for producing polymer microparticles according to claim 2 , wherein a value (Mw/Mn) obtained by dividing a weight average molecular weight (Mw) by the number average molecular weight (Mn) of the macromonomer is 2.3 or less.

13 . The method for producing polymer microparticles according to claim 3 , wherein a value (Mw/Mn) obtained by dividing a weight average molecular weight (Mw) by the number average molecular weight (Mn) of the macromonomer is 2.3 or less.

14 . A polymer microparticle obtained with the production method according to claim 2 , wherein
a volume average particle diameter thereof is 0.7 μm to 3.0 μm, a value of volume average particle diameter (dv)/number average particle diameter (dn) is 1.2 or less, and the number of byproduct small particles per 1000 polymer microparticles each having a particle diameter of 0.1 μm or more is 500 or less.

15 . A polymer microparticle obtained with the production method according to claim 3 , wherein
a volume average particle diameter thereof is 0.7 μm to 3.0 μm, a value of volume average particle diameter (dv)/number average particle diameter (dn) is 1.2 or less, and the number of byproduct small particles per 1000 polymer microparticles each having a particle diameter of 0.1 μm or more is 500 or less.

16 . A polymer microparticle obtained with the production method according to claim 4 , wherein
a volume average particle diameter thereof is 0.7 μm to 3.0 μm, a value of volume average particle diameter (dv)/number average particle diameter (dn) is 1.2 or less, and the number of byproduct small particles per 1000 polymer microparticles each having a particle diameter of 0.1 μm or more is 500 or less.

17 . The polymer microparticle according to claim 7 , wherein the macromonomer is provided with the ethylenically unsaturated groups through a portion of the carboxyl groups at an intermediate location of the molecular chain thereof.

18 . The method for producing polymer microparticles according to claim 11 , wherein a value (Mw/Mn) obtained by dividing a weight average molecular weight (Mw) by the number average molecular weight (Mn) of the macromonomer is 2.3 or less.

19 . A polymer microparticle obtained with the production method according to claim 12 , wherein
a volume average particle diameter thereof is 0.7 μm to 3.0 μm, a value of volume average particle diameter (dv)/number average particle diameter (dn) is 1.2 or less, and the number of byproduct small particles per 1000 polymer microparticles each having a particle diameter of 0.1 μm or more is 500 or less.

20 . A polymer microparticle obtained with the production method according to claim 13 , wherein
a volume average particle diameter thereof is 0.7 μm to 3.0 μm, a value of volume average particle diameter (dv)/number average particle diameter (dn) is 1.2 or less, and the number of byproduct small particles per 1000 polymer microparticles each having a particle diameter of 0.1 μm or more is 500 or less.

Assignees

• Toagosei Co Ltd

Inventors

• Saito Naohiko
• Hirano Norihiro
• Matsuzaki Hideo

Classifications

• C08F2810/30

  leading to the formation or introduction of aliphatic or alicyclic unsaturated groups · CPC title

• C08F2/18

  Suspension polymerisation · CPC title

• C08F290/126 Primary

  Polymers of unsaturated carboxylic acids or derivatives thereof · CPC title

• C08F290/12

  Polymers provided for in subclasses C08C or C08F · CPC title

• C08F8/14

  Esterification · CPC title