Process for foaming polyolefin compositions using a fluororesin/boron nitride mixture as a nucleating agent

Patent metadata

Field	Value
Publication number	US-10836879-B2
Application number	US-201616081514-A
Country	US
Kind code	B2
Filing date	Mar 28, 2016
Priority date	Mar 28, 2016
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

The process of foaming a polyolefin composition using as a nucleator a combination of a fluororesin and a boron nitride at a fluororesin-to-boron nitride weight ratio of less than 4:1. The synergistic effect between these two nucleating agents results in a higher nuclei density and a foamed product with a smaller average cell size as compared to processes using and products produced by the use of neat PTFE or neat boron nitride alone as the nucleating agent.

First claim

The invention claimed is:

1. A process of foaming a polyolefin composition, comprising the steps:
mixing a nucleator into a polyolefin, wherein the nucleator is a combination of a fluororesin and a boron nitride at a fluororesin-to-boron nitride weight ratio is in the range of from 1:1 to 1:4 further wherein the polyolefin comprises a high-density polyethylene (“HDPE”) and a low-density polyethylene (“LDPE”); and
foaming the polyolefin composition.

2. The process of claim 1 , wherein said polyolefin composition consists of HDPE and LDPE.

3. The process of claim 2 , wherein said HDPE constitutes from 45 to 95 weight percent based on the entire weight of said polyolefin composition, wherein said LDPE constitutes from 4 to 54 weight percent based on the entire weight of said polyolefin composition.

4. The process of claim 1 , wherein said fluororesin comprises polytetrafluoroethylene (“PTFE”).

5. The process of claim 1 , wherein said fluororesin and boron nitride are present in a combined amount in the range of from 0.01 to 1 weight percent based on the total weight of said polyolefin composition.

6. A foamable composition comprising, in weight percent based on the total weight of the composition:
(a) 45 to 95% HDPE;
(b) 4 to 54% LDPE;
(c) 0.01 to 1% of a combination of a fluororesin and a boron nitride at a fluororesin-to-boron nitride weight ratio is in the range of from 1:1 to 1:4.

7. A foam prepared from said foamable composition of claim 6 .

8. A cable comprising an insulation layer comprising the foam of claim 7 .

Assignees

• Sun Gangwei
• Esseghir Mohamed
• Dow Global Technologies Llc

Inventors

• Sun Gangwei
• Esseghir Mohamed

Classifications

• C08J9/00

  Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof (mechanical aspects of shaping of plastics or substances in a plastic state for the production of porous or cellular articles B29C) · CPC title

• C08K5/16

  Nitrogen-containing compounds {(C08K5/0091 takes precedence)} · CPC title

• C08L2203/202

  use in electrical wires or wirecoating · CPC title

• C08L2207/062

  HDPE · CPC title

• C08L2207/066

  LDPE (radical process) · CPC title