IMPROVED NVF COPOLYMER PROCESS
Disclosed herein is a water-soluble copolymer formed by copolymerizing N-vinylformamide and one or more vinyl C 1 -C 10 alkyl esters, and then hydrolyzing from 30 to 100 mol % of the formyl groups from the copolymerized units to form amino groups and from 30 to 100 mol % of the C 1 -C 10 alkyl ester groups from the copolymerized units to form hydroxyl groups, wherein the copolymer has a unimodal molecular weight distribution as evidenced by essentially one peak in a gel permeation gradient elution chromatographic analysis. A process to produce the polymer is also disclosed.
1 . A water-soluble copolymer formed by copolymerizing:
(a) from 99 to 1 mol % of N-vinylformamide and
(b) from 1 to 99 mol % of one or more vinyl C 1 -C 10 alkyl esters, and then hydrolyzing from 30 to 100 mol % of the formyl groups from the copolymerized units (a) to form amino groups and from 30 to 100 mol % of the C 1 -C 10 alkyl ester groups from the copolymerized units (b) to form hydroxyl groups, wherein the copolymer has a unimodal molecular weight distribution as evidenced by essentially one peak in a gel permeation gradient elution chromatographic analysis.
2 . The water-soluble copolymer of claim 1 , wherein a 4% solution of the copolymer has an APHA color value of less than or equal to about 100 APHA units determined according to ASTM D1209 or a comparable method.
3 . The water-soluble copolymer of claim 1 , wherein a 4% solution of the copolymer has an APHA color value of less than or equal to about 50 APHA units determined according to ASTM D1209 or a comparable method.
4 . The water-soluble copolymer of claim 1 , wherein the copolymer is essentially free of amidine rings as evidenced by a lack of an absorption in a 13 C NMR spectrum of the copolymer consistent with an amidine carbon atom absorption.
5 . The water soluble copolymer of claim 1 , wherein the vinyl C 1 -C 10 alkyl esters are vinyl acetate, vinyl propionate, or a combination thereof.
6 . The water soluble copolymer of claim 1 , comprising from about 0.5 mol % to about 20 mol % amine functional groups.
7 . The water soluble copolymer of claim 1 , comprising from about 5 mol % to about 15 mol % amine functional groups.
8 . The water soluble copolymer of claim 1 , wherein a 4 wt % aqueous solution of the copolymer at 20° C. has a turbidity of less than about 100 turbidity units.
9 . The water soluble copolymer of claim 1 , wherein a 4 wt % aqueous solution of the copolymer at 20° C. has a turbidity of less than about 50 turbidity units.
10 . A water-soluble copolymer formed by copolymerizing:
(a) from 99 to 1 mol % of N-vinylformamide and
(b) from 1 to 99 mol % of one or more vinyl C 1 -C 10 alkyl esters, and then hydrolyzing from 30 to 100 mol % of the formyl groups from the copolymerized units (a) to form amino groups and from 30 to 100 mol % of the C 1 -C 10 alkyl ester groups from the copolymerized units (b) to form hydroxyl groups, wherein the copolymer has a unimodal molecular weight distribution as evidenced by a 4 wt % aqueous solution having a turbidity of less than about 100 turbidity units.
11 . The water-soluble copolymer of claim 10 , wherein a 4% solution of the copolymer has an APHA color value of less than or equal to about 100 APHA units determined according to ASTM D1209 or a comparable method.
12 . The water-soluble copolymer of claim 10 , wherein a 4% solution of the copolymer has an APHA color value of less than or equal to about 50 APHA units determined according to ASTM D1209 or a comparable method.
13 . The water-soluble copolymer of claim 10 , wherein the copolymer is essentially free of amidine rings as evidenced by a lack of an absorption in a 13 C NMR spectrum of the copolymer consistent with an amidine carbon atom absorption.
14 . The water soluble copolymer of claim 10 , wherein the vinyl C 1 -C 10 alkyl esters are vinyl acetate, vinyl propionate, or a combination thereof.
15 . The water soluble copolymer of claim 10 , comprising from about 0.5 mol % to about 20 mol % amine functional groups.
16 . The water soluble copolymer of claim 10 , comprising from about 5 mol % to about 15 mol % amine functional groups.
17 . A water-soluble copolymer formed by copolymerizing
(a) from 99 to 1 mol % of N-vinylformamide and
(b) from 1 to 99 mol % of one or more vinyl C 1 -C 10 alkyl esters, and then hydrolyzing from 30 to 100 mol % of the formyl groups from the copolymerized units (a) to form amino groups and from 30 to 100 mol % of the C 1 -C 10 alkyl ester groups from the copolymerized units (b) to form hydroxyl groups, wherein the copolymer is essentially free of amidine rings as evidenced by a lack of an absorption in a 13 C NMR spectrum of the copolymer consistent with an amidine carbon atom absorption.
18 . The water-soluble copolymer of claim 17 , wherein a 4% solution of the copolymer has an APHA color value of less than or equal to about 100 APHA units determined according to ASTM D1209 or a comparable method.
19 . The water-soluble copolymer of claim 17 , wherein a 4% solution of the copolymer has an APHA color value of less than or equal to about 50 APHA units determined according to ASTM D1209 or a comparable method.
20 . The water soluble copolymer of claim 17 , wherein the vinyl C 1 -C 10 alkyl esters are vinyl acetate, vinyl propionate, or a combination thereof.
21 . The water soluble copolymer of claim 17 , comprising from about 0.5 mol % to about 20 mol % amine functional groups.
22 . The water soluble copolymer of claim 17 , comprising from about 5 mol % to about 15 mol % amine functional groups.
23 . The water soluble copolymer of claim 17 , wherein a 4 wt % aqueous solution of the copolymer at 20° C. has a turbidity of less than about 100 turbidity units.
24 . The water soluble copolymer of claim 17 , wherein a 4 wt % aqueous solution of the copolymer at 20° C. has a turbidity of less than about 50 turbidity units.
25 . A process to produce a water-soluble copolymer comprising the steps of:
a) charging a first portion of a total amount of N-vinylformamide into a reactor;
b) charging a first portion of a total amount of at least one vinyl C 1 -C 10 alkyl ester into the reactor;
c) continuously feeding a first portion of a total amount of a free radical polymerization catalyst at a first catalyst flow rate into the reactor;
d) contacting the first portion of N-vinylformamide, the first portion of at least one vinyl C 1 -C 10 alkyl ester, in the presence of the free radical polymerization catalyst under polymerization conditions for a first period of time;
e) after the first period of time, continuously feeding for a second period of time, a second portion of the n-vinylformamide at a n-vinylformamide flow rate into the reactor while simultaneously feeding a second portion of at least one vinyl C 1 -C 10 alkyl ester into the reactor at an ester flow rate, while simultaneously feeding a second portion of the free radical polymerization catalyst at a second catalyst flow rate into the reactor under polymerization conditions until the total amount of the N-vinylformamide, the total amount of the vinyl C 1 -C 10 alkyl ester, and the total amount of the free radical polymerization catalyst have been fed into the reactor;
f) followed by contacting for a third period of time, the n-vinylformamide and the at least one vinyl C 1 -C 10 alkyl ester in the presence of the free radical polymerization catalyst in the reactor under polymerization conditions to produce an intermediate copolymer comprising polyvinyl formamide and one or more polyvinyl C 1 -C 10 alkyl esters, wherein the third period of time expires when the solids content of the intermediate copolymer in the reactor is greater than or equal to about 20 wt % and less than or equal to about 70 wt %; followed by
g) saponifying the copolymer to produce polyvinyl alcohol-co-vinyl formamide
h) hydrolyzing the intermediate copolymer under either acidic or basic conditions to produce the water soluble copolymer.
26 . The process of claim 25 , wherein the water-soluble copolymer comprises:
(a) from about 0 to 30 mol % N-vinylformamide moieties;
(b) from about 99 to 1 mol % of N-vinylamine moieties
(c) from about 0 to 30 mol % of one or more vinyl C 1 -C 10 alkyl ester moieties; and
(d) from 1 to 99 mol % of vinyl alcohol moieties,
wherein the copolymer has a unimodal molecular weight distribution as evidenced by essentially one peak in a gel permeation gradient elution chromatographic analysis.
27 . The process of claim 25 , wherein water-soluble copolymer comprises:
(a) from about 0 to 30 mol % N-vinylformamide moieties;
(b) from about 99 to 1 mol % of N-vinylamine moieties
(c) from about 0 to 30 mol % of one or more vinyl C 1 -C 10 alkyl ester moieties; and
(d) from 1 to 99 mol % of vinyl alcohol moieties,
wherein the copolymer has a unimodal molecular weight distribution as evidenced by a 4 wt % aqueous solution having a turbidity of less than about 100 turbidity units.
28 . The process of claim 25 , wherein water-soluble copolymer comprises:
(a) from about 0 to 30 mol % N-vinylformamide moieties;
(b) from about 99 to 1 mol % of N-vinylamine moieties
(c) from about 0 to 30 mol % of one or more vinyl C 1 -C 10 alkyl ester moieties; and
(d) from 1 to 99 mol % of vinyl alcohol moieties,
wherein the copolymer is essentially free of amidine rings as evidenced by a lack of an absorption in a 13 C NMR spectrum of the copolymer consistent with an amidine carbon atom absorption.
29 . The process of claim 25 , wherein the free radical polymerization catalyst comprises at least one member selected from the group consisting of peroxides, redox catalysts, and azo compounds which decompose to give free radicals.
30 . The process of claim 25 , wherein the copolymerization is carried out in a solvent or diluent.
31 . The process of claim 25 , wherein the copolymerization is carried out in an aqueous solution.
32 . The process of claim 25 , wherein said hydrolysis is carried out by contacting the intermediate copolymer with an acid.
33 . The process of claim 25 , wherein said hydrolysis is carried out by contacting the intermediate copolymer with a base.