Process for Foaming Polyolefin Compositions Using a Fluororesin as a Nucleating Agent

Patent metadata

Field	Value
Publication number	US-2017327676-A1
Application number	US-201415528850-A
Country	US
Kind code	A1
Filing date	Nov 28, 2014
Priority date	Nov 28, 2014
Publication date	Nov 16, 2017
Grant date	—

Abstract

A polyolefin composition is foamed by a process in which a nucleator is used, and the nucleator comprises 80% or more of unagglomerated fluororesin particles and/or agglomerates of fluororesin particles in which both the unagglomerated particles and the agglomerates are less than 1 μm in size.

First claim

1 . A process for foaming a polyolefin composition using a fluororesin nucleating agent comprising 80% or more of agglomerates of 5 microns or more in size, the agglomerates comprising submicron particles, the process comprising the steps of: (A) reducing the size of the agglomerates to produce a fluororesin nucleating agent comprising 80% or more of particles or agglomerates of less than 1 micron in size, (B) mixing the nucleating agent of (A) with a polyolefin to produce a foamable composition, and (C) foaming the foamable composition.

2 . The process of claim 1 in which the foamable composition of (B) is made by batch mixing the nucleating agent of (A) with the polyolefin.

3 . A process for foaming a polyolefin composition, the process comprising the steps of: (A) preparing a masterbatch of a polyolefin and a fluororesin in which (1) the fluororesin comprises from 1 to 50 weight percent of the masterbatch, and (2) a majority of the fluororesin comprising agglomerates of submicron fluororesin particles, the agglomerates of 5 μm or more in size, (B) reducing the size of the fluororesin agglomerates such that 80% or more of the fluororesin in the masterbatch comprises or consists essentially of fluororesin agglomerates or fluororesin particles of a size less than 1 μm, (3) mixing the masterbatch of (B) with a polyolefin to form a mixture of the fluororesin substantially uniformly dispersed throughout the polyolefin, and (D) foaming the mixture of (C).

4 . The process of claim 1 in which the fluororesin is prepared by dispersion polymerization.

5 . The process of claim 4 in which the polyolefin of the polyolefin composition comprises high density polyethylene (HDPE) and low density polyethylene (LDPE).

6 . The process of claim 5 in which the HDPE comprises 45 to 95 weight percent of the composition based on the weight of the composition and the LDPE comprises 4 to 54 weight percent of the composition based on the weight of the composition.

7 . The process of claim 6 in which the fluororesin comprises polytetrafluoroethylene (PTFE).

8 . The process of claim 7 in which the PTFE is present in the composition in an amount of 0.01 to 1 wt % based on the weight of the composition.

9 . The process of claim 8 in which the composition further comprises at least one of an antioxidant and a cell stabilizer.

10 . A foam made by the process of claim 1 .

11 . A cable comprising an insulation layer comprising the foam of claim 10 .

12 . A masterbatch comprising or consisting essentially of a polyolefin and a fluororesin in which (1) the fluororesin comprises from 1 to 50 weight percent of the masterbatch, and (2) a majority of the fluororesin comprises agglomerates of fluororesin particles and/or unagglomerated fluororesin particles, both the agglomerates and the unagglomerated particles of submicron size.

13 . A foamable composition comprising, in weight percent based on the weight of the composition:
(A) 45 to 95% HDPE; (B) 4 to 54% LDPE; and (C) 0.01 to 1% of PTFE comprising 80%, or 85%, or more of agglomerates of PTFE particles and unagglomerated PTFE particles, both the agglomerates and the unagglomerated particles of submicron size;
the PTFE prepared by dispersion polymerization and the composition prepared by batch mixing the HDPE, LDPE and PTFE.

14 . The process of claim 3 in which the fluororesin is prepared by dispersion polymerization.

15 . The process of claim 14 in which the polyolefin of the polyolefin composition comprises high density polyethylene (HDPE) and low density polyethylene (LDPE).

16 . The process of claim 15 in which the HDPE comprises 45 to 95 weight percent of the composition based on the weight of the composition and the LDPE comprises 4 to 54 weight percent of the composition based on the weight of the composition.

17 . The process of claim 16 in which the fluororesin comprises polytetrafluoroethylene (PTFE).

18 . The process of claim 17 in which the PTFE is present in the composition in an amount of 0.01 to 1 wt % based on the weight of the composition.

19 . The process of claim 18 in which the composition further comprises at least one of an antioxidant and a cell stabilizer.

20 . A foam made by the process of claim 3 .

Assignees

• Dow Global Technologies Llc

Inventors

• Sun Gangwei
• Esseghir Mohamed
• Kmiec Chester J
• Ying Lei
• Sun Yabin
• Xu Xianmin

Classifications

• H01B3/445

  from vinylfluorides or other fluoroethylenic compounds · CPC title

• C08L23/04 Primary

  Homopolymers or copolymers of ethene · CPC title

• C08J9/0061 Primary

  characterized by the use of several polymeric components · CPC title

• C08J2427/12

  containing fluorine atoms · CPC title

• C08J2201/024

  Preparation or use of a blowing agent concentrate, i.e. masterbatch in a foamable composition · CPC title