Thermoplastic polyester resin foam sheet, thermoplastic polyester resin foam container, method for producing thermoplastic polyester resin foam sheet, and method for producing thermoplastic polyester resin foam container

Patent metadata

Field	Value
Publication number	US-2022033605-A1
Application number	US-201917277624-A
Country	US
Kind code	A1
Filing date	Sep 25, 2019
Priority date	Sep 27, 2018
Publication date	Feb 3, 2022
Grant date	—

Abstract

A thermoplastic polyester resin foam sheet includes a foam layer containing a thermoplastic polyester resin, in which a number average molecular weight Mn of the thermoplastic polyester resin is 9,000 to 26,000, a Z-average molecular weight Mz is 240,000 to 710,000, and a content of acetaldehyde in the foam layer is 25 ppm by mass or less.

First claim

1 . A thermoplastic polyester resin foam sheet comprising:
a foam layer containing a thermoplastic polyester resin, wherein a number average molecular weight Mn of the thermoplastic polyester resin contained in the foam layer is 9,000 to 26,000, a Z-average molecular weight Mz of the thermoplastic polyester resin contained in the foam layer is 240,000 to 710,000, and a content of acetaldehyde in the foam layer is 25 ppm by mass or less.

2 . The thermoplastic polyester resin foam sheet according to claim 1 , wherein a ratio represented by Mz/Mn is 8.0 to 36.0.

3 . The thermoplastic polyester resin foam sheet according to claim 1 , wherein a content of ashes in the foam layer is 5.0 mass % or less.

4 . The thermoplastic polyester resin foam sheet according to claim 1 , wherein a content of heavy metals in the foam layer is 1,000 ppm by mass or less.

5 . The thermoplastic polyester resin foam sheet according to claim 1 , wherein the thermoplastic polyester resin contained in the foam layer includes a plant-derived thermoplastic polyester resin.

6 . The thermoplastic polyester resin foam sheet according to claim 1 , wherein an amount of a gel in the thermoplastic polyester resin contained in the foam layer is 0.5% to 12.0% by weight.

7 . A thermoplastic polyester resin foam container comprising:
a foam layer containing a thermoplastic polyester resin, wherein a number average molecular weight Mn of the thermoplastic polyester resin contained in the foam layer is 9,000 to 26,000, a Z-average molecular weight Mz of the thermoplastic polyester resin contained in the foam layer is 240,000 to 710,000, and a content of acetaldehyde in the foam layer is 25 ppm by mass or less.

8 . The thermoplastic polyester resin foam container according to claim 7 , wherein a ratio represented by Mz/Mn is 8.0 to 36.0.

9 . The thermoplastic polyester resin foam container according to claim 7 , wherein a content of ashes in the foam layer is 5.0 mass % or less.

10 . The thermoplastic polyester resin foam container according to claim 7 , wherein a content of heavy metals in the foam layer is 1,000 ppm by mass or less.

11 . The thermoplastic polyester resin foam container according to claim 7 , wherein the thermoplastic polyester resin contained in the foam layer includes a plant-derived thermoplastic polyester resin.

12 . The thermoplastic polyester resin foam container according to claim 7 , wherein an amount of a gel in the thermoplastic polyester resin contained in the foam layer is 0.5% to 12.0% by weight.

13 . The thermoplastic polyester resin foam container according to claim 7 , which is a food container.

14 . A method for producing the thermoplastic polyester resin foam sheet according to claim 1 , the method comprising:
kneading a crude thermoplastic polyester resin and a foaming agent to obtain a kneaded product; and extruding and foaming the kneaded product to form the foam layer.

15 . The method for producing the thermoplastic polyester resin foam sheet according to claim 14 , wherein, in the kneading to obtain the kneaded product, the crude thermoplastic polyester resin, the foaming agent, and a crosslinking agent are kneaded to obtain the kneaded product.

16 . A method for producing a thermoplastic polyester resin foam container, the method comprising molding the thermoplastic polyester resin foam sheet according to claim 1 to obtain a container.

17 . The method for producing the thermoplastic polyester resin foam sheet according to claim 14 , wherein, in the kneading to obtain the kneaded product, a mixture containing the crude thermoplastic polyester resin, the foaming agent, and a crosslinking agent is kneaded to obtain the kneaded product.

18 . The method for producing the thermoplastic polyester resin foam sheet according to claim 14 , wherein an intrinsic viscosity (IV value) of the crude thermoplastic polyester resin is 0.50 to 1.50.

19 . The method for producing the thermoplastic polyester resin foam sheet according to claim 14 , wherein the crosslinking agent is at least one selected from the group consisting of an acid dianhydride, an oxazoline compound, and an oxazine compound.

20 . The method for producing the thermoplastic polyester resin foam sheet according to claim 14 , wherein an amount of the crosslinking agent used with respect to 100 parts by mass of the crude polyester resin is 0.08 to 0.5 parts by mass.

Assignees

• Sekisui Plastics

Inventors

• Kato Osamu

Classifications

• B29K2105/04

  cellular or porous · CPC title

• B29K2067/00

  Use of polyesters {or derivatives thereof}, as moulding material · CPC title

• B29L2031/712

  Containers; Packaging elements or accessories, Packages (closures therefor B29L2031/56; ink or toner cartridges B29L2031/7678; squeeze tubes B29L2023/20; suitcases B29L2031/7418) · CPC title

• B29C51/002

  characterised by the choice of material · CPC title

• C08G63/916

  Dicarboxylic acids and dihydroxy compounds · CPC title