US3839272A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydrolytic and melt degradation stabilized polyester
Assignee: Celanese Corp
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Filing: 1973-02-27
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Granted: 1974-10-01
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Expires: 1993-02-27
Abstract
Abstract WHERE N > OR = 3. The polyester is thereby stabilized without either substantial poisoning of the catalyst, degradation of the polymer or loss of substantial amounts of phosphorus-containing compound. Low carboxyl end group polyesters are stabilized against melt degradation and strength loss by the addition to the polyester, after the polycondensation stage, of stabilizing amounts of polyphosphoric acid having the structure
Inventors
- 👤 A Yankowsky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:08
CPC Classifications
C; C08; C08K; C08K3/00; C08K3/32
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
68 words
IN A PROCESS FOR MANUFACTURING A STABILIZED LOW CARBOXYL END GROUP FIBER OR FILM FORMING POLYESTER WHEREIN SAID POLYESTER IS THE CONDENSATION PRODUCT OF A DICARBOXYLIC ACID AND A GLYCOL OF THE SERIES HO(CH2)NOH WHEREIN N IS AN INTEGER OF FROM 2 TO 10, THE IMPROVEMENT WHICH COMPRISES THE STEP OF ADDING FROM 0.001 TO 0.045 WEIGHT PERCENT BASED ON THE POLYMER OF POLYPHOSPHORIC ACID HAVING THE STRUCTURE:
Claim 2
Dependent Claim
68 words
IN A PROCESS FOR MANUFACTURING A STABILIZED LOW CARBOXYL END GROUP FIBER OR FILM FORMING POLYESTER WHEREIN SAID POLYESTER IS THE CONDENSATION PRODUCT OF A DICARBOXYLIC ACID AND A GLYCOL OF THE SERIES HO(CH2)NOH WHEREIN N IS AN INTEGER OF FROM 2 TO 10, THE IMPROVEMENT WHICH COMPRISES THE STEP OF ADDING FROM 0.001 TO 0.045 WEIGHT PERCENT BASED ON THE POLYMER OF POLYPHOSPHORIC ACID HAVING THE STRUCTURE:
Claim 3
Dependent Claim
25 words
The process of claim 1, wherein said polyester is polyethelene terephthalate having not more than 20 free carboxyl end groups per million grams of polyester.
Claim 4
Dependent Claim
22 words
The process of claim 1, wherein said polyphosphoric acid has a P2 O5 content of between 82 and 84 percent by weIght.
Claim 5
Dependent Claim
52 words
In a process for manufacturing heat and hydrolytic stabilized polyethelene terephthalate having not more than 20 carboxyl end groups, the improvement which comprises the step of adding to the polycondensation stage, when the intrinsic viscosity is at least 0.1, from 0.001 to 0.045 percent by weight of polyphosphric acid, having the structure:
Claim 6
Dependent Claim
52 words
In a process for manufacturing heat and hydrolytic stabilized polyethelene terephthalate having not more than 20 carboxyl end groups, the improvement which comprises the step of adding to the polycondensation stage, when the intrinsic viscosity is at least 0.1, from 0.001 to 0.045 percent by weight of polyphosphric acid, having the structure:
Claim 7
Dependent Claim
21 words
The process of claim 4, wherein said polyethelene terephthalate is prepared by the direct esterification of terephthalic acid and ethylene glycol.
Claim 8
Dependent Claim
23 words
In the process of claim 4, wherein said polyethelene terephthalate is prepared by an ester interchange reaction of ethylene glycol and dimethyl terephthalate.
Claim 9
Dependent Claim
32 words
In the process of claim 4, wherein said low carboxyl end groups are obtained by the addition to the polyester, prior to the addition of said polyphosphoric acid of phenyl glycol ether.
Claim 10
Dependent Claim
17 words
The process of claim 4, wherein said polyester is subsequently hot melt extruded to form continuous filaments.
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) | 1977-09-30 | 1978-04-01 | 1978-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-30 | 1982-04-01 | 1982-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-30 | 1986-04-01 | 1986-10-01 | $7700.00 | Window Closed / Lapsed |