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Patent US4772640A successfully refreshed from Google Patents.
US4772640A
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Process for foaming polymeric compositions with organic azo compounds and compositions associated therewith
Assignee: Dow Chemical Co
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Filing: 1988-01-11
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Granted: 1988-09-20
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Expires: 2008-01-11
Abstract
Abstract Azo compounds such as 2-ethyl-6-methyl-phenylazo-t-butane which contain an aromatic moiety bridged to one or more alkyl moieties by azo groups are useful blowing agents in a novel process for foaming compositions of polymers such as polycarbonates.
Inventors
- 👤 Richard A. Wolf
- 👤 Edwin J. Wilson
- 👤 Philip J. Brondsema
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 15:41
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/04; C08J9/06; C08J9/10; C08J9/102
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
84 words
A composition of matter which contains a thermoplastic polymer and a blowing agent which comprises an azo compound with an aromatic moiety bridged to one or more aliphatic moiety by azo groups, said azo group being directly bound to the aromatic ring of an aromatic moiety and said aromatic and aliphatic moieties being chosen so that the decomposition temperature of the blowing agent is above the melting point of the polymer and at least 200° C., but below the decomposition temperature of the polymer.
Claim 2
Dependent Claim
84 words
A composition of matter which contains a thermoplastic polymer and a blowing agent which comprises an azo compound with an aromatic moiety bridged to one or more aliphatic moiety by azo groups, said azo group being directly bound to the aromatic ring of an aromatic moiety and said aromatic and aliphatic moieties being chosen so that the decomposition temperature of the blowing agent is above the melting point of the polymer and at least 200° C., but below the decomposition temperature of the polymer.
Claim 3
Dependent Claim
56 words
A composition of claim 1 wherein the polymer is a polycarbonate or a thermoplastic polycarbonate blend with copolymers which is stable at the decomposition temperature of the blowing agent, and the blowing agent has the structure: Ar--N═N--R).sub.n wherein Ar is an aromatic moiety and R is an aliphatic moiety and n is 1, 2 or 3.
Claim 4
Dependent Claim
37 words
A composition of claim 2 wherein n is 1 and Ar has the structure: ##STR4## wherein each X and R 1 are independently hydrogen or a nonmetallic moiety with a formula weight of no less than 15.
Claim 5
Dependent Claim
25 words
A composition of claim 3 wherein R is a tertiary alkyl group and each X and R 1 are independently hydrogen or an alkyl group.
Claim 6
Dependent Claim
14 words
A composition of claim 4 wherein each X is independently hydrogen, methyl or ethyl.
Claim 7
Dependent Claim
17 words
A composition of claim 5 wherein R is a tertiary butyl, pentyl, hexyl, heptyl or octyl moiety.
Claim 8
Dependent Claim
21 words
A composition of claim 6 wherein the blowing agent is selected from the group consisting of phenylazo-tert-butane, 2,6-dimethylphenylazo-tert-butane, 2-methylphenylazo-tert-butane, or 2-ethyl-6-methylphenylazo-tert-butane.
Claim 9
Dependent Claim
21 words
A composition of claim 2 wherein the blowing agent makes up about 2 to 10 percent by weight of the composition.
Claim 10
Dependent Claim
19 words
A composition of claim 8 wherein the blowing agent makes up about 5 percent of the composition by weight.
Claim 11
Dependent Claim
13 words
A composition of claim 8 wherein the polymer is in a solid form.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-09-20 | 1992-03-21 | 1992-09-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-20 | 1996-03-21 | 1996-09-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-20 | 2000-03-21 | 2000-09-20 | $7700.00 | Window Closed / Lapsed |