US4312960A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Foam crystallization of condensation polymers
Assignee: Solutia Inc
•
Filing: 1980-04-21
•
Granted: 1982-01-26
•
Expires: 2000-04-21
Abstract
Abstract A normally amorphous condensation polymer is crystallized by foaming it with a chemical blowing agent at a temperature above the softening point of the polymer, extruding the molten polymer to form a solid foam and maintaining the foam at a temperature above the glass transition temperature until crystallization occurs. The crystallized polymer foam may be used as a structural foam. It can be used in solid state polymerization to obtain polymers of enhanced degree of polymerization.
Inventors
- 👤 Morris R. Ort
- 👤 Elizabeth L. Newell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:49
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/36; C08J2367/00; C08J2367/02
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
65 words
A solid closed cell foam of crystallized linear aromatic polyester having a heat of fusion in the range of about 12 to about 40 J/g obtained by melting a normally amorphous polyester, dispersing a chemical blowing agent therein, extruding the melt to form a solid foam and maintaining the solid foam at a temperature above the glass transition temperature of the polyester until crystallization occurs.
Claim 2
Dependent Claim
65 words
A solid closed cell foam of crystallized linear aromatic polyester having a heat of fusion in the range of about 12 to about 40 J/g obtained by melting a normally amorphous polyester, dispersing a chemical blowing agent therein, extruding the melt to form a solid foam and maintaining the solid foam at a temperature above the glass transition temperature of the polyester until crystallization occurs.
Claim 3
Dependent Claim
65 words
A solid closed cell foam of crystallized linear aromatic polyester having a heat of fusion in the range of about 16 to about 30 J/g obtained by melting a normally amorphous polyester, dispersing a chemical blowing agent therein, extruding the melt to form a solid foam and maintaining the solid foam at a temperature above the glass transition temperature of the polyester until crystallization occurs.
Claim 4
Dependent Claim
65 words
A solid closed cell foam of crystallized linear aromatic polyester having a heat of fusion in the range of about 16 to about 30 J/g obtained by melting a normally amorphous polyester, dispersing a chemical blowing agent therein, extruding the melt to form a solid foam and maintaining the solid foam at a temperature above the glass transition temperature of the polyester until crystallization occurs.
Claim 5
Dependent Claim
24 words
The solid closed cell foam of claim 1 or 2 wherein the density is in the range of about 0.4 to about 1.0 g/cc.
Claim 6
Dependent Claim
32 words
The solid closed cell foam of claim 3 wherein the polyester is a condensate of a C 13 to C 17 diphenol and a C 8 to C 20 aromatic dicarboxylic acid.
Claim 7
Dependent Claim
17 words
The solid closed cell foam of claim 3 wherein the polyester is a condensate of 2,2-bis(4-hydroxyphenyl) propane.
Claim 8
Dependent Claim
20 words
The solid closed cell foam of claim 3 wherein the polyester is a condensate of 2,2-bis(4-hydroxy-phenyl) propane and isophthalic acid.
References Cited (Backward Citations)
US3036991A
Cited
US3227784A
Cited
US3384696A
Cited
US3586647A
Cited
US3585259A
Cited
US4097421A
Cited
US4051112A
Cited
US4097425A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-01-25 | 1985-07-27 | 1986-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-01-25 | 1989-07-27 | 1990-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-01-25 | 1993-07-27 | 1994-01-26 | $7700.00 | Window Closed / Lapsed |