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US4094849A
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Process for producing aqueous dispersion of ethylene-vinyl acetate copolymer containing no formalin
Assignee: Sumitomo Chemical Co Ltd
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Filing: 1976-10-27
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Granted: 1978-06-13
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Expires: 1996-10-27
Abstract
Abstract A process for producing an aqueous dispersion of ethylene-vinyl acetate copolymer containing no formalin by emulsion-polymerizng ethylene and vinyl acetate and optionally other copolymerizable vinyl monomers in the presence of a redox catalyst consisting of an oxidizing agent and a reducing agent, which is characterized in that a reaction product of a glyoxal compound and an alkali metal, ammonium or zinc salt of a reductive sulfur oxide is used as the reducing agent for the redox catalyst, in which process the polymerization temperature is easily controlled.
Inventors
- 👤 Takeo Oyamada
- 👤 Kazuhisa Satoh
- 👤 Shinobu Tsuru
- 👤 Masahiro Domoto
- 👤 Shizuo Narisawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 21:11
CPC Classifications
C; C08; C08F; C08F218/00; C08F218/02; C08F218/04; C08F218/08; C08F210/00; C08F210/02
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
78 words
A process for producing an aqueous dispersion of an ethylene-vinyl acetate copolymer containing no formalin by emulsion-polymerization ethylene and vinyl acetate and optionally other copolymerizable vinyl monomers in the presence of a redox catalyst consisting of an oxidizing agent and a reducing agent, which is characterized in that a reaction product of a glyoxal compound and an alkali metal, ammonium or zinc salt of a reductive sulfur oxide is used as the reducing agent for the redox catalyst.
Claim 2
Dependent Claim
78 words
A process for producing an aqueous dispersion of an ethylene-vinyl acetate copolymer containing no formalin by emulsion-polymerization ethylene and vinyl acetate and optionally other copolymerizable vinyl monomers in the presence of a redox catalyst consisting of an oxidizing agent and a reducing agent, which is characterized in that a reaction product of a glyoxal compound and an alkali metal, ammonium or zinc salt of a reductive sulfur oxide is used as the reducing agent for the redox catalyst.
Claim 3
Dependent Claim
59 words
The process according to claim 1, wherein the reducing agent is a reaction product of a glyoxal compound selected from the group consisting of glyoxal and methyl-glyoxal and a salt selected from the group consisting of (1) a sodium, potassium, ammonium or zinc salt of thiosulfuric acid, dithionous acid or pyrosulfurous acid, (2) sodium bisulfite and (3) potassium bisulfite.
Claim 4
Dependent Claim
28 words
The process according to claim 1, wherein the reaction product of the glyoxal compound and the salt of said reductive sulfur oxide is produced in the polymerization system.
Claim 5
Dependent Claim
27 words
The process according to claim 1, wherein the reducing agent is used in an amount of 0.25 to 3 times of the amount of the oxidizing agent.
Claim 6
Dependent Claim
19 words
The process according to claim 1, wherein said reducing agent is used in combination with a heavy metal salt.
Claim 7
Dependent Claim
18 words
The process according to claim 5, wherein said heavy metal salt is an iron salt or copper salt.
Claim 8
Dependent Claim
30 words
The process according to claim 1, wherein the amount of copolymerizable monomer is not more than 10% by weight on the basis of the total weight of the starting monomers.
References Cited (Backward Citations)
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US3746671A
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US3864297A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-06-12 | 1981-12-12 | 1982-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-12 | 1985-12-12 | 1986-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-12 | 1989-12-12 | 1990-06-13 | $7700.00 | Window Closed / Lapsed |