EP0181637A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Process for making lightly crosslinked linear polymer foams
Assignee: Dow Chemical Co
•
Filing: 1985-11-14
•
Granted: —
•
Expires: 2005-11-14
Abstract
Abstract A substantially closed-celled linear polyolefin foam is made by melt processing under pressure a linear polyolefin together with a volatile blowing agent and a cross-linking agent and then expanding the polymer. Suitable cross- linking agents, including azido and vinyl functional silanes, organic peroxides, multifunctional vinyl monomers, and oxygen, increase the melt tension and melt viscosity of the polymer by lightly cross-linking the polymer with itself to enable the production of foams having improved properties in comparison with branched polyolefin foams.
Inventors
- 👤 Chung Poo Park
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 10:47
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/0066; C08J9/0014
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
110 words
A process for preparing a lightly cross- linked linear polyolefin foam having a substantially closed-cell structure, comprising the steps of: a) melt blending under pressure at least one linear polyolefin selected from the group consisting of LLDPE, HDPE, PP and PS together with a blowing agent and sufficient amount of a cross-linking agent selected from the group consisting of azido functional silanes, vinyl functional silanes, organic peroxides, multifunctional vinyl monomers, and oxygen, to form a flowable admixture, and, b) extruding said admixture through a die to a zone of lower pressure and activating said blowing agent to expand at least one said linear polyolefin to form said lightly cross--linked foam.
Claim 2
Dependent Claim
110 words
A process for preparing a lightly cross- linked linear polyolefin foam having a substantially closed-cell structure, comprising the steps of: a) melt blending under pressure at least one linear polyolefin selected from the group consisting of LLDPE, HDPE, PP and PS together with a blowing agent and sufficient amount of a cross-linking agent selected from the group consisting of azido functional silanes, vinyl functional silanes, organic peroxides, multifunctional vinyl monomers, and oxygen, to form a flowable admixture, and, b) extruding said admixture through a die to a zone of lower pressure and activating said blowing agent to expand at least one said linear polyolefin to form said lightly cross--linked foam.
Claim 3
Dependent Claim
19 words
The process of Claim 1 in which the pressure at said die is at least 400 psig (2758 kPa).
Claim 4
Dependent Claim
31 words
The process of Claim 1 in which said cross-linking agent is 2-(trimethoxysilyl ethyl phenyl sulfonyl) azide, and a catalyst which catalyzes the condensation of silanols is added with the cross--linking agent.
Claim 5
Dependent Claim
13 words
The process of Claim 1 in which said cross-linking agent is dicumyl peroxide.
Claim 6
Dependent Claim
13 words
The process of Claim 1 in which said cross-linking agent is trimethylolpropane triacrylate.
Claim 7
Dependent Claim
14 words
The process of Claim 1 in which said crosslinking agent is vinyl trimethoxy silane.
Claim 8
Dependent Claim
58 words
The process of Claim 1 wherein in step a) said cross-linking agent is added after a flowable admixture of said at least"one linear polyolefin and said blowing agent is formed in an amount sufficient to initiate cross-linking of said at least one linear polyolefin and increase the pressure of said admixture to at least 400 psig (2758 kPa).
Claim 9
Dependent Claim
32 words
The process of Claim 1 in which said cross-linking agent is from 0.01 to 2.0 pph of an azido functional silane, and a catalyst which catalyzes the condensation of silanols is added.
Claim 10
Dependent Claim
20 words
The process of Claim 1 in which said cross-linking agent is from 0.001 to 0.5 pph of an organic peroxide.
Claim 11
Dependent Claim
21 words
The process of Claim 1 in which said cross-linking agent is from 0.01 to 2.0 pph of a multifunctional vinyl monomer.
Claim 12
Dependent Claim
23 words
A lightly cross-linked linear polyolefin foam having a substantially closed-cell structure when prepared according to the process of Claim 1 or Claim 7.
Claim 13
Dependent Claim
49 words
An expandable linear olefinic polymer composition comprising at least one linear polyolefin selected from the group consisting of LLDPE, HDPE, PP and PS, a blowing agent, and a cross-linking agent selected from the group consisting of azido functional silanes, vinyl functional silanes, organic peroxides, multifunctional vinyl monomers, and oxygen.
Claim 14
Dependent Claim
49 words
An expandable linear olefinic polymer composition comprising at least one linear polyolefin selected from the group consisting of LLDPE, HDPE, PP and PS, a blowing agent, and a cross-linking agent selected from the group consisting of azido functional silanes, vinyl functional silanes, organic peroxides, multifunctional vinyl monomers, and oxygen.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.