US3625751A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transparent astatic plastic articles having ammonium sulfonic acids groups on the surface thereof and method for their production
Assignee: Dow Chemical Co
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Filing: 1968-11-06
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Granted: 1971-12-07
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Expires: 1988-11-06
Abstract
Abstract A method for the rapid rendering of transparent polymer articles astatic by treating the articles with dilute gaseous sulfur trioxide followed by treatment with ammonia and water or dilute aqueous ammonia. The articles are rendered permanently astatic without affecting their transparency by this process.
Inventors
- 👤 Wilhelm E Walles
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 10:05
CPC Classifications
C; C08; C08J; C08J7/00; C08J7/12; C08J7/14; Y; Y10; Y10T; Y10T428/00; Y10T428/27; Y10T428/273; Y10T428/31504; Y10T428/31855; Y10T428/31909; Y10T428/31913
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
137 words
A process for the rendering of a solid transparent article of a polymer of at least 70 weight-percent styrene permanently astatic which comprises (a) contacting the surfaces of said article with gaseous sulfur trioxide in an inert gaseous diluent, the concentration of sulfur dioxide in the inert diluent being in the range from about 0.1 to about 10 volume-percent; and (b) neutralizing said sulfonated article with an ammoniacal agent selected from the group consisting of gaseous ammonia and an aqueous solution of ammonia with the proviso that when said agent is gaseous ammonia it be employed in combination with water, whereby an amount of between about 0.001 and 10 milligrams of ammonium sulfonic acid groups per square centimeter are produced on the surface of said article, said ammonium sulfonic acid groups being chemically bonded to said surface.
Claim 2
Dependent Claim
46 words
A transparent astatic article of a polymer of at least 70 weight-percent of styrene having on its surface a plurality of ammonium sulfonic acid groups chemically bonded to said surface in an amount between about 0.001 and 10 mg. of said groups per cm.2 of surface.
Claim 3
Dependent Claim
56 words
The astatic article as set forth in claim 3 wherein the polymer is a copolymer of styrene and olefinically unsaturated substituted monomer which is substituted by a member of the groups consisting of chlorine, cyano, alkanoic acyl groups of 1-4 carbon atoms, alkanoic acyloxy groups of 1-4 carbon atoms and carboalkoxy groups of 1-4 carbon atoms.
Claim 4
Dependent Claim
113 words
A transparent astatic article of a copolymer of from about 70 to about 80 percent by weight of styrene and from about 30 to about 20 percent by weight of an unsaturated, substituted hydrocarbon comonomer, said article having on its surface a plurality of ammonium sulfonic acid groups chemically bonded to said surface in an amount between about 0.001 and 10 mg. of said groups per square centimeter of surface, said substituted hydrocarbon comonomer being substituted by a member of the group consisting of chlorine, cyano, alkanoic acyl groups of 1 to 4 carbon atoms, alkanoic acyloxy groups of 1 to 4 carbon atoms and carboalkoxy groups of 1 to 4 carbon atoms.
Claim 5
Dependent Claim
26 words
An article as set forth in claim 5 in which the copolymer comprises 72 percent by weight of styrene and 28 percent by weight of acrylonitrile.
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) | 1974-12-06 | 1975-06-07 | 1975-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-06 | 1979-06-07 | 1979-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-06 | 1983-06-07 | 1983-12-07 | $7700.00 | Window Closed / Lapsed |