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US4158724A
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Tris-tetrazoles as chemical blowing agents
Assignee: BASF Corp
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Filing: 1978-09-11
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Granted: 1979-06-19
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Expires: 1998-09-11
Abstract
Abstract Tris-tetrazoles of formula I, ##STR1## wherein A is alkylene and R is hydrogen, alkyl or phenyl, are suitable blowing agents for thermoplastic resins, especially for polycarbonates and aromatic polyethers. The foaming process can be carried out at a temperature range of 230° to 300° C., the resulting foamed articles have a fine and homogeneous cellular structure. The tris-tetrazoles I can be synthesized from the corresponding tris-nitriles or tris-imidchlorides by reaction with an alkali azide.
Inventors
- 👤 Hugo Illy
- 👤 Werner Fussenegger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 07:38
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/04; C08J9/06; C08J9/10; C08J9/108
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
66 words
Process for foaming a thermoplastic resin, which process comprises adding to the resin 0.05 to 5% by weight of a tris-tetrazole of the formula I ##STR5## wherein A represents an alkylene radical of the formula --CH 2 --, --CH 2 --CH 2 -- or --CH(CH 3 )--CH 2 --, and R represents hydrogen, alkyl of 1 to 4 carbon atoms or phenyl; and heating the mixture.
Claim 2
Dependent Claim
66 words
Process for foaming a thermoplastic resin, which process comprises adding to the resin 0.05 to 5% by weight of a tris-tetrazole of the formula I ##STR5## wherein A represents an alkylene radical of the formula --CH 2 --, --CH 2 --CH 2 -- or --CH(CH 3 )--CH 2 --, and R represents hydrogen, alkyl of 1 to 4 carbon atoms or phenyl; and heating the mixture.
Claim 3
Dependent Claim
19 words
Process according to claim 1, wherein there is added a tris-tetrazole of the formula I wherein R represents hydrogen.
Claim 4
Dependent Claim
28 words
Process according to claim 1, wherein the thermoplastic resin is polypropylene, a styrene copolymer, a polycarbonate, a polyamide, an aromatic polyether, an aromatic polyester or an aromatic polysulphone.
Claim 5
Dependent Claim
16 words
Process according to claim 1, wherein the thermoplastic resin is a polycarbonate or an aromatic polyether.
Claim 6
Dependent Claim
13 words
Process according to claim 1, wherein the mixture is heated at 230°-300° C.
Claim 7
Dependent Claim
20 words
Process according to claim 1, wherein 0.1 to 2% by weight of a compound of the formula I is added.
References Cited (Backward Citations)
US3442829A
Cited
US3873477A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-06-18 | 1982-12-18 | 1983-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-06-18 | 1986-12-18 | 1987-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-06-18 | 1990-12-18 | 1991-06-19 | $7700.00 | Window Closed / Lapsed |