Patent US3676378A successfully refreshed from Google Patents.
US3676378A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Continuous production of expandable thermoplastics
Assignee: BASF SE
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Filing: 1970-03-25
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Granted: 1972-07-11
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Expires: 1990-03-25
Abstract
Abstract Continuous production of styrene polymers which contain an expanding agent and which are in the form of granules by extrusion of a mixture of a melt of the polymer with the expanding agent and rapid cooling of the extruded mixture, wherein excess expanding agent is first mixed with the melt and then the excess of expanding agent is evaporated. In this way both the production of a homogeneous mixture and the cooling of the mixture prior to extrusion to temperatures just above the softening point of the mixture are facilitated.
Inventors
- 👤 Eduard Heil
- 👤 Hans-Georg Trieschmann
- 👤 Herbert Willersinn
- 👤 Herbert Bolte
- 👤 Klaus Bronstert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 11:08
CPC Classifications
B; B29; B29C; B29C44/00; B29C44/34; B29C44/36; B29C44/46; B29C44/461; B29B; B29B9/00; B29B9/02; B29B9/06; B29B9/12; B29C44/3442; C; C08; C08J; C08J9/00; C08J9/16
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
38 words
A process as in claim 1 wherein the mixture which is at a pressure higher than the vapor pressure of the expanding agent is cooled to a temperature of 20* above to 60* C below the glass temperature.
Claim 2
Dependent Claim
29 words
A process as in claim 1 wherein the amount of expanding agent incorporated in the polymer is from 30 to 160 percent by weight with reference to said polymer.
Claim 3
Dependent Claim
24 words
A process as in claim 1 wherein the amount of expanding agent incorporated in the polymer is from 30 to 160 percent by weight.
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) | 1975-07-11 | 1976-01-10 | 1976-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-11 | 1980-01-10 | 1980-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-11 | 1984-01-10 | 1984-07-11 | $7700.00 | Window Closed / Lapsed |