US3717620A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Arylene sulfide resin oxidative curing process
Assignee: Phillips Petroleum Co
•
Filing: 1971-07-20
•
Granted: 1973-02-20
•
Expires: 1991-07-20
Abstract
Abstract A process for oxidatively pre-curing arylene sulfide resins stepwise by subjecting the particulate resin to oxidation at a temperature below the melting point of the resin for a period of time sufficient to reduce the melt flow of the resin and withdraw periodically at least a portion of the partially cured resin to obtain successive products having decreasing melt flow suitable for special applications requiring specific melt flow range.
Inventors
- 👤 R Rohlfing
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 05:42
CPC Classifications
C; C08; C08G; C08G75/00; C08G75/02; C08G75/0204; C08G75/0286; C08G75/0295
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
205 words
A step-wise process regulated as to time and temperature to provide successive products from single batches of arylene sulfide resins having decreasing melt flow values suitable for special applications requiring a specific melt flow range for each application which comprises the steps of: a. subjecting uncured particulate arylene sulfide resin to oxidative pre-curing by contacting the particulate resin with an oxygen-containing gas at a temperature ranging from about 25* to about 125* F. below the melting point of said resin for a period of time sufficient to substantially reduce the melt flow of the resin, b. withdrawing a portion of said resin of reduced melt flow as product having desired melt flow properties, c. subjecting said resin remaining in step (b) after said withdrawal to further oxidative pre-curing by contacting with an oxygen-containing gas at said temperature below the melting point of said resin for an additional period of time sufficient to further reduce the melt flow of said resin, d. withdrawing another portion of said resin of further reduced melt flow as product having desired melt flow properties, and e. continuing the previous steps of oxidative pre-curing and intermediate withdrawal of partially oxidatively pre-cured resin until the desired final melt flow value is reached.
Claim 2
Dependent Claim
205 words
A step-wise process regulated as to time and temperature to provide successive products from single batches of arylene sulfide resins having decreasing melt flow values suitable for special applications requiring a specific melt flow range for each application which comprises the steps of: a. subjecting uncured particulate arylene sulfide resin to oxidative pre-curing by contacting the particulate resin with an oxygen-containing gas at a temperature ranging from about 25* to about 125* F. below the melting point of said resin for a period of time sufficient to substantially reduce the melt flow of the resin, b. withdrawing a portion of said resin of reduced melt flow as product having desired melt flow properties, c. subjecting said resin remaining in step (b) after said withdrawal to further oxidative pre-curing by contacting with an oxygen-containing gas at said temperature below the melting point of said resin for an additional period of time sufficient to further reduce the melt flow of said resin, d. withdrawing another portion of said resin of further reduced melt flow as product having desired melt flow properties, and e. continuing the previous steps of oxidative pre-curing and intermediate withdrawal of partially oxidatively pre-cured resin until the desired final melt flow value is reached.
Claim 3
Dependent Claim
140 words
A process for the pre-curing of arylene sulfide resins to a plurality of products having different melt flow values wherein each product has value for a different utility which comprises: a. subjecting a particulate arylene sulfide resin to oxidative precuring in plural stages by contacting with an oxygen-containing gas at a temperature ranging from about 25* to about 125* F. below the melting point of the resin for a period of time sufficient to substantially reduce the melt flow of the resin during each heating stage, and b. withdrawing as product after each heating stage at least a portion of the resin of reduced melt flow produced during each heating stage prior to subjecting the remainder of the resin of reduced melt flow to additional oxidative pre-curing and heating to provide another portion of resin further reduced in melt flow.
Claim 4
Dependent Claim
140 words
A process for the pre-curing of arylene sulfide resins to a plurality of products having different melt flow values wherein each product has value for a different utility which comprises: a. subjecting a particulate arylene sulfide resin to oxidative precuring in plural stages by contacting with an oxygen-containing gas at a temperature ranging from about 25* to about 125* F. below the melting point of the resin for a period of time sufficient to substantially reduce the melt flow of the resin during each heating stage, and b. withdrawing as product after each heating stage at least a portion of the resin of reduced melt flow produced during each heating stage prior to subjecting the remainder of the resin of reduced melt flow to additional oxidative pre-curing and heating to provide another portion of resin further reduced in melt flow.
Claim 5
Dependent Claim
46 words
A process according to claim 2 wherein the temperature during each heating stage is within the range of about 50* to 100* F. below the melting point of the resin being pre-cured, the tIme is in the range 2-8 hours, and the oxygen-containing gas is air.
Claim 6
Dependent Claim
45 words
A process according to claim 2 wherein the particulate arylene sulfide resin being cured is purged in a zone with air as the oxidizing and purging medium and wherein there is periodic removal of partially oxidized cured resin from the purged bed of particulate resin.
Claim 7
Dependent Claim
49 words
A process according to claim 2 wherein the process is carried out by a batchwise curing of the entire batch of particulate arylene sulfide resin with periodic removal of product between heating stages until the desired final melt flow for the final portion of resin is obtained or reached.
Claim 8
Dependent Claim
130 words
A process according to claim 2 wherein the arylene sulfide resin is polyphenylene sulfide, the oxygen-containing gas is air, and there are approximately five different products of different melt flow values recovered during the oxidative pre-curing process and further wherein the melt flow as determined by differential thermal analysis (DTA) by heating a 10 mg sample of the polymer at a rate of 10* C. per minute for each successive product withdrawn is as follows: 1st product - melt flow is 1,200 + or - 200 2nd product - melt flow is 500 + or - 100 3rd product - melt flow is 175 + or - 50 4th product - melt flow is 50 + or - 25 5th product - melt flow is 1,700 + or - 300
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) | 1976-02-20 | 1976-08-21 | 1977-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-20 | 1980-08-21 | 1981-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-20 | 1984-08-21 | 1985-02-20 | $7700.00 | Window Closed / Lapsed |