Method for producing polyethylene-based resin extruded foam sheet, polyethylene-based resin extruded foam sheet, and plate interleaf sheet using the same for glass sheets

Patent metadata

Field	Value
Publication number	US-10717840-B2
Application number	US-201615559148-A
Country	US
Kind code	B2
Filing date	Mar 22, 2016
Priority date	Mar 26, 2015
Publication date	Jul 21, 2020
Grant date	Jul 21, 2020

Abstract

Provided is a method for producing a polyethylene-based resin extruded foam sheet by extruding and foaming a foamable molten resin composition formed by kneading a mixture containing a low-density polyethylene, a physical blowing agent, and an antistatic agent, wherein the foam sheet has a thickness in a range of from 0.05 to 0.5 mm, and the antistatic agent is a polymeric antistatic agent having a melting point whose different from the melting point of the low-density polyethylene is in a range of from −10 to +10° C., and having a melt flow rate of 10 g/10 min or more. This method enables a novel polyethylene-based resin extruded foam sheet to be obtained that is of high quality such that formation of a small hole or a through-hole has been reduced or eliminated, and has both excellent strength and a shock-absorbing property despite a very small thickness even in medium- or long-term continuous production, and besides, exhibits a sufficient antistatic property, thus suitable as a glass plate interleaf sheet.

First claim

The invention claimed is:

1. A method for producing a polyethylene-based resin extruded foam sheet by extruding and foaming a foamable molten resin composition containing a low-density polyethylene, a physical blowing agent, and an antistatic agent,
wherein the foam sheet has a thickness in a range of from 0.05 to 0.5 mm,
wherein the low density polyethylene has a melt flow rate of about 15 g/10 minutes or more,
wherein the antistatic agent is a polymeric antistatic agent having a melting point whose difference from a melting point of the low-density polyethylene is in a range of from −10 to +10° C., and has a melt flow rate of 10 g/10 min or more,
wherein the foamable molten resin composition does not contain a high-density polyethylene, and
wherein the foam sheet is reeled in a rolled shape.

2. The method for producing a polyethylene-based resin extruded foam sheet according to claim 1 , wherein the melting point of the polymeric antistatic agent is 120° C. or less.

3. The method for producing a polyethylene-based resin extruded foam sheet according to claim 1 , wherein a ratio of a melt flow rate of the low-density polyethylene to the melt flow rate of the polymeric antistatic agent (a melt flow rate of the low-density polyethylene/the melt flow rate of the polymeric antistatic agent) is 2 or less.

4. The method for producing a polyethylene-based resin extruded foam sheet according to claim 1 , wherein the polymeric antistatic agent is added in an amount in a range of from 3 to 25 parts by mass per 100 parts by mass of the low-density polyethylene.

5. A polyethylene-based resin extruded foam sheet containing an antistatic agent, and a low-density polyethylene as a matrix resin,
wherein the foam sheet has a thickness in a range of from 0.05 mm to 0.5 mm and an apparent density in a range of from 20 to 450 kg/m 3 ,
wherein the low density polyethylene has a melt flow rate of about 15 g/10 minutes or more,
wherein the antistatic agent is a polymeric antistatic agent having a melting point whose difference from a melting point of the low-density polyethylene is in a range of from −10° C. to +10° C., and having a melt flow rate of 10 g/10 min or more,
wherein the polyethylene-based resin extruded foam sheet does not contain a high-density polyethylene, and
wherein the foam sheet is reeled in a rolled shape.

6. An interleaf sheet for glass plates, comprising the extruded polyethylene-based resin foam sheet according to claim 5 .

7. The method for producing a polyethylene-based resin extruded foam sheet according to claim 1 , wherein a resin component of the polyethylene-based resin consists essentially of low density polyethylene.

8. The method for producing a polyethylene-based resin extruded foam sheet according to claim 1 , wherein a blend content of a resin other than low-density polyethylene contained in the polyethylene-based resin is 20 parts by mass or less per 100 parts by mass of low-density polyethylene.

Assignees

• Jsp Corp

Inventors

• Aoki Takeshi
• Nishimoto Takashi

Classifications

• B29K2471/00

  Use of polyethers {, e.g. PEEK, i.e. polyether-etherketone or PEK, i.e. polyetherketone or derivatives thereof,} as filler · CPC title

• B29K2995/0091

  Damping, energy absorption · CPC title

• B29K2423/00

  Use of polyalkenes {or derivatives thereof} as filler · CPC title

• C08J2203/204

  of chemical foaming agent and physical blowing agents · CPC title

• B29L2031/7138

  Shock absorbing · CPC title