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US4812279A
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Process for preparation of cellulose ester films
Assignee: SGI ACQUISTION Corp C/O STERLING GROUP Inc EIGHT GREENWAY PLAZA STE 702 HOUSTON TX 77046 A CORP OF TX
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Filing: 1987-06-12
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Granted: 1989-03-14
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Expires: 2007-06-12
Abstract
Abstract Disclosed is a process for the preparation of cellulose ester films, which comprises dissolving a cellulose ester in an organic solvent, coating the solution on a substrate under rotation and peeling the film formed on the substrate from the substrate, wherein a second organic solvent having a compatibility with the organic solvent and being a poor solvent to the cellulose ester is added to the organic solvent solution of the cellulose ester to precipitate a cellulose ester having a high molecular weight in the cellulose ester, the cellulose ester having a high molecular weight is separated from the solution, and the remaining cellulose ester solution is formed into a cellulose ester film by the rotational film-forming method. The cellulose ester film prepared according to this process is excellent in the thickness uniformity and free of color nonuniformity or streaks and has good optical properties.
Inventors
- 👤 Hiroaki Nakagawa
- 👤 Masahiro Kondo
- 👤 Noriake Ohishi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:48
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/62; C; C08; C08J; C08J5/00; C08J5/18; C08J2301/00; C08J2301/08; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24942; Y10T428/2495; Y10T428/24967
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
115 words
A process for the preparation of cellulose ester films, which comprises dissolving a cellulose ester in an organic solvent, coating the solution on a substrate under rotation and peeling the film formed on the substrate from the substrate, wherein a second organic solvent having a compatibility with the organic solvent and being a poor solvent to the cellulose ester is added to the organic solvent solution of the cellulose ester to precipitate a cellulose ester having a high molecular weight in the cellulose ester, the cellulose ester having a high molecular weight is separated from the solution, and the remaining cellulose ester solution is formed into a cellulose ester film by the rotational film-forming method.
Claim 2
Dependent Claim
115 words
A process for the preparation of cellulose ester films, which comprises dissolving a cellulose ester in an organic solvent, coating the solution on a substrate under rotation and peeling the film formed on the substrate from the substrate, wherein a second organic solvent having a compatibility with the organic solvent and being a poor solvent to the cellulose ester is added to the organic solvent solution of the cellulose ester to precipitate a cellulose ester having a high molecular weight in the cellulose ester, the cellulose ester having a high molecular weight is separated from the solution, and the remaining cellulose ester solution is formed into a cellulose ester film by the rotational film-forming method.
Claim 3
Dependent Claim
12 words
A process according to claim 1, wherein the cellulose ester is nitrocellulose.
Claim 4
Dependent Claim
13 words
A process according to claim 1, wherein the cellulose ester is cellulose propionate.
Claim 5
Dependent Claim
17 words
A process according to claim 2, wherein the nitration degree of the nitrocellulose is 11 to 12.5%.
Claim 6
Dependent Claim
15 words
A process according to claim 1, wherein the organic solvent is a ketone type solvent.
Claim 7
Dependent Claim
23 words
A process according to claim 1, wherein the organic solvent is methylisobutyl ketone or a mixed solvent of methylisobutyl ketone and methyl alcohol.
Claim 8
Dependent Claim
26 words
A process according to claim 1, wherein the boiling point of the second organic solvent is lower than the boiling point of the first organic solvent.
Claim 9
Dependent Claim
21 words
A process according to claim 1, wherein the second organic solvent is an aliphatic hydrocarbon solvent or an alicyclic hydrocarbon solvent.
Claim 10
Dependent Claim
13 words
A process according to claim 1, wherein the second organic solvent is hexane.
Claim 11
Dependent Claim
35 words
A process according to claim 1, wherein the second organic solvent is added to the cellulose ester solution in a volume 0.8 to 1.5 times as large as the volume of the first organic solvent.
Claim 12
Dependent Claim
33 words
A process according to claim 1, wherein the weight average molecular weight of the cellulose ester in the cellulose ester solution left after separation of the high-mulecular-weight cellulose ester is 150,000 to 350,000.
Claim 13
Dependent Claim
138 words
A process for the preparation of nitrocellulose films, which comprises forming a solution of nitrocellulose in methylisobutyl ketone or a mixture of methylisobutyl ketone and methyl alcohol as the solvent which contains nitrocellulose and methylisobutyl ketone at a weight ratio of from 30/1 to 10/1, adding hexane as the poor solvent to the solution so that the hexane/solvent volume ratio is from 0.8 to 1.5, to thereby precipitate nitrocellulose having a high molecular weight, separating the precipitated nitrocellulose having a high molecular weight from the solution, heating the remaining solution at a temperature higher than the boiling point of the poor solvent to separate the poor solvent, filtering the remaining solution, coating the filtered solution on a substrate under rotation to form a film of nitrocellulose on the substrate, and peeling the formed nitrocellulose film from the substrate.
Claim 14
Dependent Claim
138 words
A process for the preparation of nitrocellulose films, which comprises forming a solution of nitrocellulose in methylisobutyl ketone or a mixture of methylisobutyl ketone and methyl alcohol as the solvent which contains nitrocellulose and methylisobutyl ketone at a weight ratio of from 30/1 to 10/1, adding hexane as the poor solvent to the solution so that the hexane/solvent volume ratio is from 0.8 to 1.5, to thereby precipitate nitrocellulose having a high molecular weight, separating the precipitated nitrocellulose having a high molecular weight from the solution, heating the remaining solution at a temperature higher than the boiling point of the poor solvent to separate the poor solvent, filtering the remaining solution, coating the filtered solution on a substrate under rotation to form a film of nitrocellulose on the substrate, and peeling the formed nitrocellulose film from the substrate.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-03-13 | 1992-09-12 | 1993-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-13 | 1996-09-12 | 1997-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-13 | 2000-09-12 | 2001-03-14 | $7700.00 | Window Closed / Lapsed |