Expandable composite resin bead

Patent metadata

Field	Value
Publication number	US-9505898-B2
Application number	US-201414508016-A
Country	US
Kind code	B2
Filing date	Oct 7, 2014
Priority date	Oct 11, 2013
Publication date	Nov 29, 2016
Grant date	Nov 29, 2016

Abstract

An expandable composite resin bead comprises: a composite resin containing a polyethylene resin and a polystyrene resin; and a blowing agent impregnating the composite resin. The composite resin contains 5 to 20 mass % of the polyethylene resin and 80 to 95 mass % of the polystyrene resin. The blowing agent is an organic physical blowing agent. Furthermore, in the expandable composite resin bead, a predetermined swelling degree in methyl ethyl ketone at a temperature of 23° C. is not lower than 1.25.

First claim

What is claimed is:

1. An expandable composite resin bead comprising: a composite resin containing a polyethylene resin and a polystyrene resin; and a blowing agent impregnated in the composite resin, wherein
the composite resin contains the polyethylene resin by 5 to 20 mass % and the polystyrene resin by 80 to 95 mass %, based on 100 mass % of a total of the polyethylene resin and the polystyrene resin,
the blowing agent is an organic physical blowing agent, and
a swelling degree, in methyl ethyl ketone at a temperature of 23° C., of a mixed insoluble matter of a xylene insoluble matter obtained through Soxhlet extraction of the expandable composite resin bead using xylene and an acetone insoluble matter contained in a xylene solution after the Soxhlet extraction, is not lower than 1.25.

2. The expandable composite resin bead according to claim 1 , wherein the composite resin contains the polyethylene resin by 5 to 17 mass % and the polystyrene resin by 83 to 95 mass %, based on 100 mass % of a total of the polyethylene resin and the polystyrene resin.

3. The expandable composite resin bead according to claim 1 , wherein the polyethylene resin comprises a linear low density polyethylene whose difference between melting point and Vicat softening temperature is not higher than 20° C.

4. The expandable composite resin bead according to claim 1 , wherein the swelling degree is 1.25 to 10.00.

5. The expandable composite resin bead according to claim 1 , wherein the swelling degree is 1.50 to 5.00.

6. The expandable composite resin bead according to claim 1 , wherein a weight ratio of the xylene insoluble matter is from 0 to 40%.

7. The expandable composite resin bead according to claim 1 , wherein the polyethylene resin forms a continuous phase and the polystyrene resin forms a dispersed phase in the composite resin.

8. The expandable composite resin bead according to claim 1 , wherein an interface ratio of the polyethylene resin and the polystyrene resin at a cross section of the expandable composite resin bead is larger than 6 μm/μm 2 but not larger than 50 μm/μm 2 .

9. The expandable composite resin bead according to claim 1 , wherein a weight ratio of the xylene insoluble matter is from 5 to 35%.

10. The expandable composite resin bead according to claim 1 , wherein a weight ratio of the xylene insoluble matter is from 10 to 30%.

11. The expandable composite resin bead according to claim 1 , wherein the organic physical blowing agent is a saturated hydrocarbon compound having a carbon number of 3 to 6.

12. The expandable composite resin bead according to claim 1 , wherein the organic physical blowing agent is a mixture of 30 to 80 mass % of isobutane and 20 to 70 mass % of a hydrocarbon having a carbon number of 4 to 6 other than isobutane, based on 100 mass % of a total of isobutene and the hydrocarbon other than isobutane.

13. The expandable composite resin bead according to claim 1 , wherein a content of the blowing agent in the expendable composite resin is from 3 to 10 mass %.

14. The expandable composite resin bead according to claim 1 , wherein a content of the blowing agent in the expendable composite resin is from 4 to 9 mass %.

Assignees

• Jsp Corp

Inventors

• Shima Masaomi

Classifications

• C08J2325/06

  Polystyrene · CPC title

• C08J2323/06

  Polyethene · CPC title

• C08L23/0815

  with aliphatic 1-olefins containing one carbon-to-carbon double bond · CPC title

• C08L2312/00

  Crosslinking · CPC title

• C08L2205/04

  containing interpenetrating networks · CPC title