# US 8,465,836 B2 · Method for producing single-hole hollow polymer particles

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- Number: US 8,465,836 B2
- Document ID: US8465836B2
- Status: Granted
- Kind: B2
- Application number: 13/254,927
- Filed: 2010-07-27
- Published: 2012-07-26
- Granted: 2013-06-18
- Earliest claimed: 2010-07-27
- Assignees: Sekisui Chemical Co., Ltd.
- Applicants: Hiroshi Yamauchi; Yasuyuki Yamada
- Inventors: Hiroshi Yamauchi; Yasuyuki Yamada
- Web page: https://patentgrep.com/patent/US8465836B2

## CPC

- C08F 2/44: Polymerisation in the presence of compounding ingredients, e.g. plasticisers, dyestuffs, fillers
- B01J 13/14: Polymerisation; cross-linking
- C08F 2/20: with the aid of macromolecular dispersing agents
- Y10T 428/2982: Particulate matter [e.g., sphere, flake, etc.]
- Y10T 428/2991: Coated
- Y10T 428/2998: including synthetic resin or polymer
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Provided is a method for producing single-hole hollow polymer particles which have an extremely uniform outside diameter and inside diameter, and thus do not require a classifying operation. Further provided are single-hole hollow polymer particles produced by such a method for producing single-hole hollow polymer particles. The invention relates to a method for producing single-hole hollow polymer particles, which includes: preparing a dispersion of swollen particle droplets by mixing a seed particle dispersion obtained by dispersing uncrosslinked polymer-containing seed particles in a water-containing dispersion medium, with a radical polymerizable monomer, an oil-soluble solvent and an oil-soluble polymerization initiator, and causing the radical polymerizable monomer, the oil-soluble solvent and the oil-soluble polymerization initiator to be absorbed in the seed particles; and polymerizing the radical polymerizable monomer in the swollen particle droplets. The relationship between the SP value of a polymer obtained by polymerizing the radical polymerizable monomer (SPp) and the SP value of the oil-soluble solvent (SPs) satisfies formula (1) below: 2.1≦SPp−SPs≦7.0 (1).

## Claims

### Claim 1

A method for producing single-hole hollow polymer particles, which comprises:
preparing a dispersion of swollen particle droplets by mixing a seed particle dispersion obtained by dispersing uncrosslinked polymer-containing seed particles in a water-containing dispersion medium, with a radical polymerizable monomer, an oil-soluble solvent and an oil-soluble polymerization initiator, and causing the radical polymerizable monomer, the oil-soluble solvent and the oil-soluble polymerization initiator to be absorbed in the seed particles; and
polymerizing the radical polymerizable monomer in the swollen particle droplets,
wherein the relationship between the SP value of a polymer obtained by polymerizing the radical polymerizable monomer (SPp) and the SP value of the oil-soluble solvent (SPs) satisfies formula (1) below:
2.1≦SPp−SPs≦7.0 (1).

### Claim 2 (depends on 1)

The method for producing single-hole hollow polymer particles according to claim 1,
wherein an emulsion obtained by dispersing the radical polymerizable monomer, the oil-soluble solvent and the oil-soluble polymerization initiator in a water-containing dispersion medium is mixed with the seed particle dispersion.

### Claim 3 (depends on 1)

The method for producing single-hole hollow polymer particles according to claim 1,
wherein the seed particles have a particle size coefficient of variation (Cv) of 30% or less.

### Claim 4 (depends on 1)

The method for producing single-hole hollow polymer particles according to claim 1,
wherein the radical polymerizable monomer contains a nitrile monomer.

### Claim 5 (depends on 1)

Single-hole hollow polymer particles produced by the method for producing single-hole hollow polymer particles according to claim 1.

### Claim 6 (depends on 5)

The single-hole hollow polymer particles according to claim 5,
which have an average outside diameter of from 0.1 to 100 μm and an outside diameter Cv of 10% or less.

### Claim 7 (depends on 5)

The single-hole hollow polymer particles according to claim 5,
which have an inside diameter Cv of 10% or less.

### Claim 8 (depends on 5)

The single-hole hollow powder particles according to claim 5,
which are thermally expandable.