Patent US4587271A successfully refreshed from Google Patents.
US4587271A
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US
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Polymer foam, thermoformed shapes thereof and methods of forming same
Assignee: Pactiv LLC
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Filing: 1984-06-18
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Granted: 1986-05-06
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Expires: 2004-06-18
Abstract
Abstract A foam structure having a density of less than about 20 lbs/ft3. The method of forming the same comprising forming a homogeneous melt blend under pressure of a polymer member selected from the group consisting of polyetherimide resin particles, polycarbonate resin particles, a polymer blend of polyphenylene oxide and polystyrene in particle form imbibed with a blowing agent, followed by extrusion of the same into a lower pressure atmosphere. A composition comprising said particles imbibed with methylene chloride, chloroform, 1,1,2-trichloroethane or mixtures thereof. A method of thermoforming said foam in sheet form.
Inventors
- 👤 Charles M. Krutchen
- 👤 Wen-Pao Wu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:03
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/04; C08J9/12; C08J9/14; C08J9/143; C08J9/144; C08J9/145; B; B29; B29C; B29C44/00; B29C44/34; B29C44/36; B29C44/46; B29C44/50; B29C44/507; B29C51/00; B29C51/002; B29K; B29K2079/00; C08J2379/00; C08J2379/04; C08J2379/08; Y; Y10; Y10S; Y10S264/00; Y10S264/05; Y10S264/66; Y10S521/00; Y10S521/918
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
59 words
A composition comprising discrete particles of a polyetherimide imbibed with a solvent member selected from the group consisting of methylene chloride, chloroform, 1,1,2-trichloroethane and mixtures thereof said imbibed particles being in at least substantially free flowable form, said solvent being present in a quantity sufficient to foam said resin to a density less than about 20 lbs/ft 3 .
Claim 2
Dependent Claim
59 words
A composition comprising discrete particles of a polyetherimide imbibed with a solvent member selected from the group consisting of methylene chloride, chloroform, 1,1,2-trichloroethane and mixtures thereof said imbibed particles being in at least substantially free flowable form, said solvent being present in a quantity sufficient to foam said resin to a density less than about 20 lbs/ft 3 .
Claim 3
Dependent Claim
21 words
The composition of claim 1 containing up to about 30 parts of said solvent member per 100 parts of said polymer.
Claim 4
Dependent Claim
49 words
The composition of claim 1 wherein said polyetherimide is a polymer of the following structure: ##STR3## wherein n is a positive integer, Ar is a divalent radical containing from 6-20 carbon atoms, R is a bivalent radical selected from the group consisting of aliphatic, cycloaliphatic, aromatic and araliphatic groups.
Claim 5
Dependent Claim
17 words
The composition of claim 3 wherein the precursor of Ar is Bisphenol A and R is phenylene.
Claim 6
Dependent Claim
16 words
The composition of claim 1 wherein said density is less than about 5 lbs./ft 3 .
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-05-05 | 1989-11-04 | 1990-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-05 | 1993-11-04 | 1994-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-05 | 1997-11-04 | 1998-05-06 | $7700.00 | Window Closed / Lapsed |