Patent US4164489A successfully refreshed from Google Patents.
US4164489A
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Continuous emulsion polymerization of vinyl acetate and ethylene
Assignee: Air Products and Chemicals Inc
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Filing: 1978-04-24
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Granted: 1979-08-14
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Expires: 1998-04-24
Abstract
Abstract This invention relates to an improved continuous process for producing vinyl acetate-ethylene copolymer emulsions. The improvement for continuous polymerization of vinyl acetate and ethylene comprises continuously charging a reaction mixture containing vinyl acetate and ethylene to a polymerization vessel, conducting an initial polymerization of the vinyl acetate and ethylene in the presence of a seed latex under ethylene pressure and continuously removing the thus formed latex from the initial polymerization vessel at an unreacted vinyl acetate monomer content from 5-20% by weight of the latex and then effecting a post polymerization of the unreacted vinyl acetate at an ethylene pressure of not more than about 300 psia until the unreacted vinyl acetate in the latex is less than 1% by weight.
Inventors
- 👤 Wiley E. Daniels
- 👤 William E. Lenney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 14:37
CPC Classifications
C; C08; C08F; C08F263/00; C08F263/02; C08F263/04
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
195 words
In a continuous process for forming a latex comprising the steps of polymerizing a reaction mixture comprising vinyl acetate, ethylene, water, a free radical initiator, and a protective colloid under pressure to form a latex containing a copolymer consisting essentially of vinyl acetate, ethylene and 0-10% of other vinyl monomer, the improvement which comprises: (a) continuously charging said reaction mixture to a polymerization vessel; (b) conducting an initial polymerization of said reaction mixture in said polymerization vessel in the presence of a seed latex for a sufficient time and sufficient temperature to form a vinyl acetate ethylene copolymer, said copolymer having a glass transition temperature of from minus 20° C. to plus 10° C.; and (c) continuously removing latex formed in (b) from the polymerization vessel at a rate commensurate with that of step (a) when the unreacted vinyl acetate content by weight of the latex is from 5-20% of said latex formed in (b) and then effecting post-polymerization of the unreacted vinyl acetate in the removed latex at an ethylene pressure of not more than about 300 psia until the unreacted vinyl acetate in the removed latex is not more than 1% by weight.
Claim 2
Dependent Claim
195 words
In a continuous process for forming a latex comprising the steps of polymerizing a reaction mixture comprising vinyl acetate, ethylene, water, a free radical initiator, and a protective colloid under pressure to form a latex containing a copolymer consisting essentially of vinyl acetate, ethylene and 0-10% of other vinyl monomer, the improvement which comprises: (a) continuously charging said reaction mixture to a polymerization vessel; (b) conducting an initial polymerization of said reaction mixture in said polymerization vessel in the presence of a seed latex for a sufficient time and sufficient temperature to form a vinyl acetate ethylene copolymer, said copolymer having a glass transition temperature of from minus 20° C. to plus 10° C.; and (c) continuously removing latex formed in (b) from the polymerization vessel at a rate commensurate with that of step (a) when the unreacted vinyl acetate content by weight of the latex is from 5-20% of said latex formed in (b) and then effecting post-polymerization of the unreacted vinyl acetate in the removed latex at an ethylene pressure of not more than about 300 psia until the unreacted vinyl acetate in the removed latex is not more than 1% by weight.
Claim 3
Dependent Claim
30 words
The process of claim 1 wherein said seed latex is provided in a proportion to provide from about 2-8% solids by weight of the vinyl acetate in the reaction mixture.
Claim 4
Dependent Claim
18 words
The process of claim 2 wherein said seed latex has a particle size of from about 0.1-0.5 microns.
Claim 5
Dependent Claim
19 words
The process of claim 3 wherein the initial polymerization is carried out at a temperature of from 40°-75° C.
Claim 6
Dependent Claim
17 words
The process of claim 4 wherein the post-polymerization is carried out at a temperature of 25°-80° C.
Claim 7
Dependent Claim
29 words
The process of claim 3 wherein the latex is removed from the initial polymerization zone when the unreacted vinyl acetate is from about 12-16% by weight of the latex.
Claim 8
Dependent Claim
22 words
The process of claim 6 wherein the protective colloid is selected from the group consisting of polyvinyl alcohol and a cellulose ether.
Claim 9
Dependent Claim
42 words
The process of claim 6 or 7 wherein the post-polymerization is carried out at a temperature of from 45° C. to 55° C., and the residual vinyl acetate in the latex is reduced in the post-polymerization to less than 0.6% by weight.
Claim 10
Dependent Claim
21 words
The process of claim 6 wherein said post-polymerization is carried out at an ethylene pressure of not more than 30 psia.
Claim 11
Dependent Claim
69 words
The process of claim 3, 4, 5, or 9 wherein said seed latex is selected from the group consisting of polyvinyl acetate homopolymer, vinyl acetate-ethylene copolymer having a Tg of from -14° to 4° C., and a vinyl acetate-lower alkyl acrylate copolymer with the vinyl acetate being present in a proportion of at least 85% by weight and said seed latex having a particle size of from 0.15-0.25 microns.
Claim 12
Dependent Claim
48 words
The process of claim 9 wherein the free radical initiator is a redox catalyst which includes a reducing agent and an oxidizing agent, and the mole ratio of reducing agent to oxidizing agent is from about 0.5-1.5:1 in the initial polymerization zone, and 0.2-0.6:1 in the post-polymerization zone.
Claim 13
Dependent Claim
20 words
The process of claim 9 wherein the reaction mixture consists essentially of vinyl acetate, ethylene, water and free radical initiator.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-08-13 | 1983-02-12 | 1983-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-08-13 | 1987-02-12 | 1987-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-08-13 | 1991-02-12 | 1991-08-14 | $7700.00 | Window Closed / Lapsed |