Patent US4190718A successfully refreshed from Google Patents.
US4190718A
Expired / Lapsed
US
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Process for increasing molecular weight of vinylpyrrolidone polymer
Assignee: ISP Investments LLC
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Filing: 1975-05-27
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Granted: 1980-02-26
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Expires: 1995-05-27
Abstract
Abstract The process for increasing the molecular weight of poly-N-vinylpyrrolidone over that normally obtained by suspension polymerization of N-vinylpyrrolidone in a saturated hydrocarbon suspension medium, by adding to the suspension medium a controlled amount of water, specifically an amount between about 1% and 35% by weight based on the total weight of N-vinylpyrrolidone monomer. The significantly higher molecular weight of the resulting polymeric product can be still further increased by additionally incorporating in the suspension medium between about 0.001 mol % and about 1 mol % of a difunctional vinyl cross-linking agent per mol of N-vinylpyrrolidone monomer. The polymeric products of the present invention are preferably water soluble granules having a porous structure; although the present invention also concerns the poly-N-vinylpyrrolidone having a number average molecular weight of between 400,000 and 2,000,000, preferably between 450,000 and 1,500,000 in any physical form.
Inventors
- 👤 Donald H. Lorenz
- 👤 Earl P. Williams
- 👤 Herman S. Schultz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 11:21
CPC Classifications
C; C08; C08F; C08F26/00; C08F26/06; C08F26/10; C09; C09K; C09K8/00; C09K8/58; C09K8/588; Y; Y10; Y10S; Y10S507/00; Y10S507/903; Y10S507/935; Y10S507/936; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
123 words
In a process for the polymerization of N-vinylpyrrolidone in a liquid medium with a free radical polymerization initiator in a reaction zone, the improvement which comprises: forming a liquid mixture comprising N-vinylpyrrolidone monomer, at least an equivalent amount up to 3.5 parts by weight per part of monomer of a saturated aliphatic hydrocarbon of 5 to 20 carbon atoms as a suspension medium, a suspension aid, and a controlled amount between about 1% by weight and about 35% by weight of water per weight of monomer in the mixture; agitating said liquid mixture to form a suspension of N-vinylpyrrolidone liquid globules and reacting said N-vinylpyrrolidone in suspension to produce a solid polymer of N-vinylpyrrolidone having a number-average molecular weight of at least 200,000.
Claim 2
Dependent Claim
123 words
In a process for the polymerization of N-vinylpyrrolidone in a liquid medium with a free radical polymerization initiator in a reaction zone, the improvement which comprises: forming a liquid mixture comprising N-vinylpyrrolidone monomer, at least an equivalent amount up to 3.5 parts by weight per part of monomer of a saturated aliphatic hydrocarbon of 5 to 20 carbon atoms as a suspension medium, a suspension aid, and a controlled amount between about 1% by weight and about 35% by weight of water per weight of monomer in the mixture; agitating said liquid mixture to form a suspension of N-vinylpyrrolidone liquid globules and reacting said N-vinylpyrrolidone in suspension to produce a solid polymer of N-vinylpyrrolidone having a number-average molecular weight of at least 200,000.
Claim 3
Dependent Claim
28 words
The process of claim 1 wherein the controlled amount of water is present in an amount between about 2% by weight and about 30% by weight of monomer.
Claim 4
Dependent Claim
55 words
The process of claim 1 wherein the suspension is formed by presuspending a mixture comprising a major portion of the total amount of monomer in the suspension medium, the controlled amount of water, and the suspension aid and adding to said presuspension a mixture comprising the remaining minor portion of monomer and the polymerization initiator.
Claim 5
Dependent Claim
22 words
The process of claim 3 wherein the presuspension is heated to about polymerization temperature prior to the addition of the monomer-initiator mixture.
Claim 6
Dependent Claim
36 words
The process of claim 1 wherein there is added to said liquid mixture, between about 0.001 and about 1.0 mol % based on monomer of a difunctional, polyunsaturated crosslinking agent containing 6 to 20 carbon atoms.
Claim 7
Dependent Claim
11 words
The process of claim 5 wherein the cross-linking agent is diallylphthalate.
Claim 8
Dependent Claim
12 words
The process of claim 5 wherein the cross-linking agent is diallylpolyethylene glycol.
Claim 9
Dependent Claim
17 words
The process of claim 5 wherein the cross-linking agent forms a part of the initial liquid mixture.
Claim 10
Dependent Claim
41 words
The process of claim 1 wherein the product polymer is separated from the reaction by filtration to form a filter cake and wherein the filter cake is washed with a solvent having a boiling point below about 100° C., and dried.
Claim 11
Dependent Claim
20 words
The process of claim 9 wherein the dried product is removed from the filter and ground to smaller particle size.
Claim 12
Dependent Claim
27 words
The process of claim 5 wherein the product polymer is separated from the reaction by filtration, washed with a solvent boiling below about 100° C. and dried.
Claim 13
Dependent Claim
27 words
The process of claim 5 wherein the cross-linked polymeric product of the process is obtained as discrete porous particles having a diameter not more than 25 mils.
Claim 14
Dependent Claim
27 words
The process of claim 5 wherein the cross-linked polymeric product of the process is obtained as discrete porous particles having a diameter not more than 25 mils.
Claim 15
Dependent Claim
96 words
The process of claim 1 wherein the liquid mixture contains between 1 part by weight and 3.5 parts by weight C 5 to C 20 paraffin as said liquid suspension medium per part by weight N-vinylpyrrolidone monomer; and between about 0.05% and about 5% by weight of a free radical initiator based on monomer, and said suspension of said liquid globules is reacted at a temperature between about 50° C. and about 120° C. under a pressure of from about 15 mm Hg to about 25 p.s.i.g. for a period of from 2 to 12 hours.
Claim 16
Dependent Claim
30 words
The process of claim 14 wherein the liquid mixture additionally contains between about 0.005 mol % and about 0.5 mol % based on monomer, of a difunctional polyunsaturated cross-linking agent.
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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) | 1983-02-25 | 1983-08-27 | 1984-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-02-25 | 1987-08-27 | 1988-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-02-25 | 1991-08-27 | 1992-02-26 | $7700.00 | Window Closed / Lapsed |