US4069194A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the solid state polycondensation of linear polyesters
Assignee: LL Plant Engineering AG
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Filing: 1975-11-07
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Granted: 1978-01-17
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Expires: 1995-11-07
Abstract
Abstract A separating or anticaking agent consisting of spherical glass particles having a diameter of 3 to 30μ is added to polyester resin granulates to prevent agglomeration during solid state polycondensation in a plug-flow reactor. Thin-walled articles formed from the end product are characterized by high strength, high transparency, crystal clear color, good gas impermeability and a smooth surface.
Inventors
- 👤 Werner Gey
- 👤 Wolfgang Langhauser
- 👤 Helmut Heinze
- 👤 Hans-Joachim Rothe
- 👤 Peter Freund
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:06
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/78; C08G63/80; Y; Y10; Y10S; Y10S524/00; Y10S524/908
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
91 words
Process for solid-state polycondensation of linear polyesters in granulated form comprising moving the granulate in an inert gas stream at temperatures of 30° to 5° C below the melting point of the polymer continuously through a reaction vessel, and preventing agglutination of the granulate by an addition of fine-particle glass as a separating agent, characterized in the prior to entering the reactor there is admixed with the granulate 0.2 to 5% by weight of a glass powder having particles of substantially spherical form with a diameter between about 3 and 30μ.
Claim 2
Dependent Claim
91 words
Process for solid-state polycondensation of linear polyesters in granulated form comprising moving the granulate in an inert gas stream at temperatures of 30° to 5° C below the melting point of the polymer continuously through a reaction vessel, and preventing agglutination of the granulate by an addition of fine-particle glass as a separating agent, characterized in the prior to entering the reactor there is admixed with the granulate 0.2 to 5% by weight of a glass powder having particles of substantially spherical form with a diameter between about 3 and 30μ.
Claim 3
Dependent Claim
21 words
Process according to claim 1, in which the polyester granulates range in size between about 1 and 5 mm maximum length.
Claim 4
Dependent Claim
32 words
Process according to claim 1 in which the spherical glass particles have a diameter between about 5 and 25μ, and the polyester granulates are between about 2 and 4 mm maximum length.
Claim 5
Dependent Claim
22 words
Process according to claim 1 wherein the indices of refraction of said spherical particles and said condensed polyester are substantially the same.
References Cited (Backward Citations)
US3305532A
Cited
GB1010043A
Cited
US3583935A
Cited
US3621074A
Cited
US3544523A
Cited
US3634359A
Cited
US3876608A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-01-16 | 1981-07-18 | 1982-01-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-16 | 1985-07-18 | 1986-01-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-16 | 1989-07-18 | 1990-01-17 | $7700.00 | Window Closed / Lapsed |