US4940733A
Expired / Lapsed
US
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Method for foaming high temperature polymers using poly(alkylene carbonates) as foaming agents
Assignee: PAC POLYMER Inc A CORP OF
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Filing: 1989-11-28
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Granted: 1990-07-10
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Expires: 2009-11-28
Abstract
Abstract A process for producing cellular foamed articles from high temperature engineering polymers wherein polymeric blowing agents are utilized to expand the polymers. The process comprises mixing a first polymer capable of being foamed with a second polymer comprising at least one poly(alkylene carbonate) to provide a polymer blend; heating the polymer blend to a temperature sufficient to melt the polymer to be foamed and to decompose the second polymer to form gas inclusions within the first polymer; expanding the melted first polymer containing the gas inclusions to form a foamed article; and cooling the foamed article to a temperature below the melting or softening point of the foamed article. Polymers which may be foamed according to the process include those polymers which can tolerate processing temperatures in excess of 260 DEG C. Suitable poly(alkylene carbonate) foaming agents include poly(propylene carbonate), blends of two or more poly(alkylene carbonates) and copolymers and terpolymers formed by polymerizing two or more oxirane compounds in the presence of carbon dioxide.
Inventors
- 👤 Jeffrey A. Kuphal
- 👤 Lloyd M. Robeson
- 👤 Joseph G. Santangelo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 04:25
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/04; C08J9/06; C08J9/08; C08J9/0061; C08J2371/00; C08J2371/08; C08J2371/10; C08J2371/12; C08J2379/00; C08J2379/04; C08J2379/08; C08J2381/00; C08J2381/04; C08J2381/06; C08J2469/00
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
162 words
A process for producing a foamed article from a polymer capable of being foamed which comprises: (a) mixing first polymer capable of being foamed is selected from the group consisting of polysulfone poly(ether sulfone), poly(aryl sulfone), poly(aryl ether sulfone), poly(etherimide), poly(amide-imide), poly(aryl ether ketone), modified poly(phenylene ether), amorphous polyamides and poly(phenylene sulfide) and copolymers and terpolymers as well as blends of the above mentioned polymers with a second polymer comprising a homopolymer or copolymer of propylene carbonate or a blend of the propylene carbonate polymer with at least one other alkylene carbonate polymer to provide a polymer blend; (b) heating the polymer blend to a temperature sufficient to melt the polymer to be foamed and to decompose the second polymer to form gas inclusions within the first polymer; (c) expanding the melted first polymer containing the gas inclusions to form a foamed article; and (d) cooling the foamed article to a temperature below the melting or softening point of the foamed article.
Claim 2
Dependent Claim
162 words
A process for producing a foamed article from a polymer capable of being foamed which comprises: (a) mixing first polymer capable of being foamed is selected from the group consisting of polysulfone poly(ether sulfone), poly(aryl sulfone), poly(aryl ether sulfone), poly(etherimide), poly(amide-imide), poly(aryl ether ketone), modified poly(phenylene ether), amorphous polyamides and poly(phenylene sulfide) and copolymers and terpolymers as well as blends of the above mentioned polymers with a second polymer comprising a homopolymer or copolymer of propylene carbonate or a blend of the propylene carbonate polymer with at least one other alkylene carbonate polymer to provide a polymer blend; (b) heating the polymer blend to a temperature sufficient to melt the polymer to be foamed and to decompose the second polymer to form gas inclusions within the first polymer; (c) expanding the melted first polymer containing the gas inclusions to form a foamed article; and (d) cooling the foamed article to a temperature below the melting or softening point of the foamed article.
Claim 3
Dependent Claim
16 words
The process according to claim 1 wherein the first polymer capable of being foamed is poly(sulfone).
Claim 4
Dependent Claim
16 words
The process according to claim 1 wherein the first polymer capable of being foamed is polyetherimide.
Claim 5
Dependent Claim
18 words
The process according to claim 1 wherein the first polymer capable of being foamed comprises a poly(phenylene ether).
Claim 6
Dependent Claim
82 words
The process according to claim 1 wherein the second polymer has covalently linked units of the general structural formulae: ##STR5## wherein R 1 is a hydrogen atom or a linear or branched alkyl group having from about 1 to six carbon atoms; R 2 is selected from H or CH 3 ; and R 3 is an alkylene group having from about 2 to 6 carbons atoms which may optionally contain an oxygen atom or a sulfur atom in the alkylene backbone.
Claim 7
Dependent Claim
26 words
The process according to claim 5 wherein R 1 is selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl and the isomers of pentyl and hexyl.
Claim 8
Dependent Claim
13 words
The process according to claim 5 wherein R 2 is a hydrogen atom.
Claim 9
Dependent Claim
11 words
The process according to claim 6 wherein R 2 is methyl.
Claim 10
Dependent Claim
46 words
The process according to claim 6 wherein R 3 is selected from C 2 H4, C 5 H 10 , C 6 H 12 , C 7 H 14 , C 16 H 32 , C 4 H 8 O and C 4 H 8 S.
Claim 11
Dependent Claim
13 words
The process according to claim 1 wherein the second polymer comprises poly(propylene carbonate).
Claim 12
Dependent Claim
21 words
The process according to claim 1 wherein the poly(propylene carbonate) has an average molecular weight ranging from about 1000 to 1,000,000.
Claim 13
Dependent Claim
41 words
The process according to claim 1 further comprising mixing a nucleating agent selected from talc, wollastonite, attapulgus clay, kaolin clay, calcium carbonate and citric acid into the polymer to be foamed and the second polymer comprising at least one poly(alkylene carbonate).
Claim 14
Dependent Claim
19 words
The process according to claim 1 wherein the second polymer is a blend of two or more poly(alkylene carbonates).
Claim 15
Dependent Claim
89 words
The process according to claim 1 wherein the second polymer is a copolymer formed by polymerizing carbon dioxide and two or oxirane compounds represented by the formulae: ##STR6## wherein R 1 is a hydrogen atom or linear or branched alkyl group having from about 1 to six carbon atoms; R 2 is selected from H or CH 3 ; and R 3 is an alkylene group having from about 2 to 6 carbons atoms which may optionally contain an oxygen atom or a sulfur atom in the alkylene backbone.
Claim 16
Dependent Claim
26 words
The process according to claim 14 wherein R 1 is selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl and the isomers of pentyl or hexyl.
Claim 17
Dependent Claim
19 words
The process according to claim 14 wherein R 2 is selected from a hydrogen atom or a methyl group.
Claim 18
Dependent Claim
38 words
The process according to claim 14 wherein R 3 is selected from C 2 H 4 , C 5 H 10 , C 6 H 12 , C 4 H 8 O or C 4 H 8 S.
Claim 19
Dependent Claim
27 words
The process according to claim 1 wherein the expanding according to step (c) comprising extruding the polymer blend containing the gas inclusions to form the foamed article.
Claim 20
Dependent Claim
28 words
The process according to claim 1 wherein the expanding according to step (c) comprises injection molding the polymer blend containing the gas inclusions to form the foamed article.
Claim 21
Dependent Claim
27 words
The process according to claim 1 wherein the expanding according to step (c) comprises compression molding the polymer containing the gas inclusions to form the formed article.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1993-07-09 | 1994-01-08 | 1994-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-09 | 1998-01-08 | 1998-07-10 | $3760.00 | Window Closed / Lapsed |
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