US3678016A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fabrication of shaped articles cross-linked by chemical addition reactions
Assignee: Dow Chemical Co
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Filing: 1967-02-27
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Granted: 1972-07-18
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Expires: 1987-02-27
Abstract
Abstract ''''Cross-linking of a reactive polymer and a curing agent which occurs by a chemical addition reaction has been found to be reversible at elevated temperatures. The reversible nature of the cross-linking reaction makes it possible to prepare more uniformly crosslinked articles by separately heating a polymer such as styrene-maleic anhydride and a polyol, combining them at elevated temperatures and then by cooling form uniform crosslinks. Another feature of the invention provides for heating a cross-linked article to reverse the cross-links, fluidize the composition, reform it and then cool to recross-link the composition. Useful coreactive functional groups include a polymer with a hydroxyl group and a curing agent with anhydride groups or a polymer with carboxylic acid groups and a curing agent with vinyl ether groups.
Inventors
- 👤 Robert L Zimmerman
- 👤 Kent S Dennis
- 👤 Eugene R Moore
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:25
CPC Classifications
C; C08; C08K; C08K5/00; C08K5/0008; C08K5/0025
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
104 words
a curing agent having more than one functional group wherein the functional group is primary or secondary hydroxyl, -NHR where R is an alkyl or aromatic radical, a five- or six-membered cyclic anhydride or CH2=CHO-, and wherein the functional group is selected to be coreactive by chemical addition with the functional group of the polymer; B. combining the curing agent with the polymer at the desired elevated temperature in such proportions so as to provide a composition containing from one-tenth to 1 1/2 functional groups of curing agent per functional group of polymer, C. forming the article, and D. cooling to set the composition.
Claim 2
Dependent Claim
28 words
The process of claim 1 wherein the vinyl addition polymer is a copolymer of a vinyl aromatic monomer and a Alpha , Beta -unsaturated dicarboxylic acid anhydride monomer.
Claim 3
Dependent Claim
78 words
a curing agent having more than one functional group wherein the functional group is five- or six-membered cyclic anhydride or CH2=CHO-, and wherein the functional group Is selected to be coreactive by chemical addition with the functional group of the polymer; said composition containing the curing agent in such proportions so as to provide from one-tenth to about 1 functional group per functional group of the polymer; B. forming the article, and C. cooling to set the article.
Claim 4
Dependent Claim
18 words
The process of claim 2 wherein the vinyl addition polymer is a copolymer of maleic anhydride and styrene.
Claim 5
Dependent Claim
31 words
The process of claim 1 wherein the vinyl addition polymer is a copolymer of styrene and acrylic or methacrylic acid and the curing agent is a divinyl ether of diethylene glycol.
Claim 6
Dependent Claim
25 words
The process of claim 1 wherein the vinyl addition polymer is a copolymer of styrene and hydroxy-ethyl methacrylate or of styrene and N-(t-butyl) amino-ethyl methacrylate.
Claim 7
Dependent Claim
16 words
The process of claim 1 wherein the curing agent is piperidine, N,N''-diisopropyl p-phenylenediamine or N,N''-dimethyl ethylenediamine.
Claim 8
Dependent Claim
25 words
The process of claim 1 wherein the curing agent is a glycol, a polyalkylene glycol or a dihydric alcohol containing three or more carbon atoms.
Claim 9
Dependent Claim
24 words
A process for forming shaped articles which comprises: A. heating to a temperature of about 175* to about 300* C. a cross-linked composition comprising:
Claim 10
Dependent Claim
18 words
The process of claim 8 wherein the vinyl addition polymer is a copolymer of styrene and hydroxy-ethyl methacrylate.
Claim 11
Dependent Claim
31 words
The process of claim 8 wherein the vinyl addition polymer is a copolymer of styrene and acrylic or methacrylic acid and the curing agent is a divinyl ether of diethylene glycol.
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) | 1975-07-18 | 1976-01-17 | 1976-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-18 | 1980-01-17 | 1980-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-18 | 1984-01-17 | 1984-07-18 | $7700.00 | Window Closed / Lapsed |