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US4810570A Expired / Lapsed US ⏱️ 0.0 years remaining

Polyolefin foams having open and/or closed pores and consisting of polyolefins of ultrahigh molecular weight, process for their production, and their use

Assignee: DSM IP Assets BV
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Filing: 1988-07-25
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Granted: 1989-03-07
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Expires: 2008-07-25
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Abstract

Abstract The invention relates to polyolefin foams consisting of polyolefins of ultrahigh molecular weight, i.e. weight-average molecular weight from about 4×10 5 to 6×10 6 g/mol and higher, and to a novel process for producing these foams by foaming a solution of a polyolefin of ultrahigh molecular weight in a solvent with the use of a physical or chemical blowing agent or of an inert gas blown into the solution, and cooling of the resulting foam to a temperature below the gelling temperature of the polyolefin. If appropriate, these foams can be provided wholly or partially with a smooth skin on their surface by superficial cooling, if appropriate under the action of pressure. These foams are distinguished by high tensile strength and impact strength values, shock-absorbing properties, low glass transition temperatures, low embrittlement at low temperatures and high chemical resistance, and they are used especially as mechanical and acoustic insulating materials, materials of construction, filter agents and implantation materials.

Inventors

  • 👤 Hendrikus J. J. Rutten
  • 👤 Pieter B. Pluyter

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-01 22:48
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/26; C08J9/04; C08J9/06; C08J9/12; C08J9/14; C08J9/141; C08J9/28; C08J2201/00; C08J2201/04; C08J2201/048; C08J2201/0482; C08J2201/0484; C08J2201/05; C08J2201/0502; C08J2323/00; C08J2323/02; C08J2323/04; Y; Y10; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249987; Y10T428/249988; Y10T428/249989; Y10T428/249991; Y10T428/249992

Claims Analysis

Total Claims: 14
Claim 1
Independent Claim 25 words
A polyolefin foam having open and/or closed pores and consisting of a polyolefin of ultrahigh molecular weight of more than 400,000 g/mol (weight-average molecular weight).
Claim 2
Dependent Claim 25 words
A polyolefin foam having open and/or closed pores and consisting of a polyolefin of ultrahigh molecular weight of more than 400,000 g/mol (weight-average molecular weight).
Claim 3
Dependent Claim 17 words
A polyolefin foam as claimed in claim 1, which is provided wholly or partially with a skin.
Claim 4
Dependent Claim 12 words
A polyolefin foam as claimed in claim 1, which consists of polyethylene.
Claim 5
Dependent Claim 19 words
A polyolefin foam as claimed in claim 3, which has a density from 0.01 to 0.8 g/cm 3 .
Claim 6
Dependent Claim 41 words
A process for producing a polyolefin foam as claimed in claim 1, which comprises foaming a solution of polyolefin of ultrahigh molecular weight in a solvent and cooling the resulting foam to a temperature below the gelling temperature of the polyolefin.
Claim 7
Dependent Claim 19 words
A process as claimed in claim 5, wherein the polyolefin foam is provided wholly or partially with a skin.
Claim 8
Dependent Claim 25 words
A process as claimed in claim 6, wherein the skin is produced by superficially cooling the polyolefin foam, if appropriate under the action of pressure.
Claim 9
Dependent Claim 18 words
A process as claimed in claim 5, wherein the foam is generated by physical or chemical blowing agents.
Claim 10
Dependent Claim 18 words
A process as claimed in claim 5, wherein the foam is generated by removal of the polyolefin solvent.
Claim 11
Dependent Claim 19 words
A process as claimed in claim 9, wherein the foam is generated by evaporation of the solvent or freeze-drying.
Claim 12
Dependent Claim 28 words
A process as claimed in claim 5, wherein the polyolefin foam is crosslinked while it is being cooled to a temperature below the gelling temperature or subsequently thereto.
Claim 13
Dependent Claim 66 words
A process as claimed in claim 5, wherein, for entangling the polymer molecules, the foam, if it no longer contains any solvent, is heated to a temperature between 10° C. below the crystallization temperature.and below the decomposition temperature of the polyolefin or, if the foam still contains solvent, it is heated to a temperature above the dissolution temperature and below the decomposition temperature of the polyolefin.
Claim 14
Dependent Claim 25 words
A mechanical or acoustic insulating material, a material of construction, a filter agent or an implantation material made from the foam according to claim 1.

References Cited (Backward Citations)

US4033929A Cited
US4655769A Cited
US4692269A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1992-03-06 1992-09-05 1993-03-07 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1996-03-06 1996-09-05 1997-03-07 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2000-03-06 2000-09-05 2001-03-07 $7700.00 Window Closed / Lapsed

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