Patent US4075173A successfully refreshed from Google Patents.
US4075173A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the production of aromatic polyesters from hydroxybenzoic acid and products thereof
Assignee: Sumitomo Chemical Co Ltd
•
Filing: 1977-01-28
•
Granted: 1978-02-21
•
Expires: 1997-01-28
Abstract
Abstract A process for the production of aromatic polyesters which comprises preparing a prepolymer by subjecting the compounds of the formulae: ##STR1## to heat-polycondensation in the molar ratios of (I) : (II) = 1 : 100 to 100 : 1 and (II) : (III) = 1 : 10 to 10 : 1, pulverizing the prepolymer thus prepared and then heating the resultant in an inert gas or under reduced pressure.
Inventors
- 👤 Takashi Maruyama
- 👤 Katsuji Ueno
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 15:40
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/78; C08G63/80; C08G63/02; C08G63/60; C08G63/605
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
99 words
A process for producing an aromatic polyester which comprises preparing a prepolymer by subjecting the compounds of the formulae: ##STR5## to heat-polycondensation at a temperature of 200°-380° C in the molar ratios of (1) : (II) = 1 : 100 to 100 : 1 and (II) : (III) = 1 : 10 to 10 : 1, pulverizing the prepolymer thus prepared and then heating the resultant in an inert gas or under reduced pressure at a temperature within the range of 200° to less than 380° C while raising the temperature at the rate of 1° to 20° C/hour.
Claim 2
Dependent Claim
99 words
A process for producing an aromatic polyester which comprises preparing a prepolymer by subjecting the compounds of the formulae: ##STR5## to heat-polycondensation at a temperature of 200°-380° C in the molar ratios of (1) : (II) = 1 : 100 to 100 : 1 and (II) : (III) = 1 : 10 to 10 : 1, pulverizing the prepolymer thus prepared and then heating the resultant in an inert gas or under reduced pressure at a temperature within the range of 200° to less than 380° C while raising the temperature at the rate of 1° to 20° C/hour.
Claim 3
Dependent Claim
22 words
The process according to claim 1, wherein the molar ratio of (I) to (II) is 1 : 10 to 10 : 1.
Claim 4
Dependent Claim
19 words
The process according to claim 1, wherein the molar ratio of (II) to (III) is about 1 : 1.
Claim 5
Dependent Claim
24 words
The process according to claim 1, wherein the molar ratio of terephthalic acid to isophthalic acid is 100 : 0 to 50 : 50.
Claim 6
Dependent Claim
17 words
The process according to claim 1, wherein said heat-polycondensation is carried out for 1 to 10 hours.
Claim 7
Dependent Claim
33 words
The process according to claim 1, wherein said prepolymer is preheated at 100° to 200° C for 5 to 30 hours in an inert gas or under reduced pressure prior to said heating.
Claim 8
Dependent Claim
13 words
An aromatic polyester obtained by the process as set forth in claim 1.
References Cited (Backward Citations)
US3637595A
Cited
US3884876A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-02-20 | 1981-08-22 | 1982-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-20 | 1985-08-22 | 1986-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-20 | 1989-08-22 | 1990-02-21 | $7700.00 | Window Closed / Lapsed |