Glyoxalation of vinylamide polymer
View Patent ↗The present invention is directed to a method for preparing a cellulose reactive adduct of polyvinylamide and a composition resulting from the method. The preparation of the cellulose reactive adduct is carried out close to a Critical Concentration defined herein. When the reaction is run close to this Critical Concentration, the risk of gelation is minimized, consumed glyoxal is maximized, and shelf live is enhanced. Additionally, the glyoxalated vinylamides of the present invention impart improved wet and dry strengthening efficiency to paper and paperboard when compared to adducts disclosed in previously described art.
1. A paper or board comprising a cellulose reactive functionalized polyvinylamide adduct prepared by a process comprising
reacting a substantially aqueous reaction mixture of a vinylamide polymer and a cellulose reactive agent to form the adduct,
wherein the concentration of the vinylamide polymer is below, equal to or no more than 1% above a Critical Concentration and the Critical Concentration is defined as the concentration of the vinylamide polymer above which the viscosity increases for the reaction mixture resulting from the forward progress of the adduct formation, and below which, the viscosity decreases for the reaction mixture resulting from the forward progress of adduct formation;
wherein the adduct is characterized by a viscosity of no more than 30 centipoise measured using a BROOKFIELD viscometer at a speed of 60 rpm and a temperature of 25° C.;
wherein the reaction is run in a continuous mode or in a batch mode.
2. The paper or board according to claim 1 , wherein the molar ratio of amide to cellulose reactive agent is in the range of about 2:1 to about 12:1.
3. The paper or board according to claim 1 , wherein the adduct is a reaction product of vinylamide polymer and glyoxal and the vinylamide polymer has an average molecular weight of at least about 30,000 to at least about 5,000,000 wherein at least 40 wt. % of the total glyoxal has been consumed.
4. The paper or board according to claim 1 , which further includes a second polymer in addition to the vinylamide polymer and/or formed adduct.
5. The paper or board according to claim 1 wherein the cellulose reactive agent comprises more than one aldehyde functionality.
6. The paper or board according to claim 1 , wherein the cellulose reactive agent is glyoxal, glutaraldehyde, furan dialdehyde, 2-hydroxyadipaldehyde, succinaldehyde, dialdehyde starch, diepoxy compounds, or combinations thereof.
7. The paper or board according to claim 1 , wherein the vinylamide polymer is a homopolymer or copolymer formed from (meth)acrylamide or a substituted (meth)acrylamide.
8. The paper or board according to claim 1 , wherein the vinylamide polymer is nonionic, cationic, potentially cationic, anionic, potentially anionic, or amphoteric, or combinations thereof.
9. The paper or board according to claim 1 , wherein the vinylamide polymer is cationic and formed from (meth)acrylamide or a substituted (meth)acrylamide and a cationic monomer, wherein the cationic monomer is selected from the group consisting of diallyldialkyl ammonium salts, (dialkylamino)alkyl(meth) acrylates acid addition or quaternary salts, 2-vinylpyridines acid addition or quaternary salts, dialkylamino alkyl(meth)acrylamides acid addition or quaternary salts, (p-vinylphenyl)-trimethylammonium chloride and 1-methacryloyl-4-methyl piperazine acid addition or quaternary ammonium salts.
10. The paper or board according to claim 1 , wherein the vinylamide polymer is formed from about 20 to about 99 weight percent of (meth)acrylamide or a substituted (meth)acrylamide monomer.
11. The paper or board according to claim 1 , wherein the vinylamide polymer is a copolymer of (meth)acrylamide and diallyclimethylammonium halide.
12. A method for increasing the wet or dry strength of paper or board comprising the steps:
a) providing an aqueous slurry of cellulosic fibers;
adding a cellulose reactive functionalized polyvinylamide adduct to the aqueous slurry of cellulosic fibers; or
b) spraying, coating or applying a cellulose reactive functionalized polyvinylamide adduct onto a wet web, paper or board,
wherein the adduct is prepared by a process comprising reacting a substantially aqueous reaction mixture of a vinylamide polymer and a cellulose reactive agent to form the adduct,
wherein the concentration of the vinylamide polymer is below, equal to or no more than 1% above a Critical Concentration and the Critical Concentration is defined as the concentration of the vinylamide polymer above which the viscosity increases for the reaction mixture resulting from the forward progress of the adduct formation, and below which, the viscosity decreases for the reaction mixture resulting from the forward progress of adduct formation;
wherein the adduct is characterized by a viscosity of no more than 30 centipoise measured using a BROOKFIELD viscometer at a speed of 60 rpm and a temperature of 25° C.;
wherein the reaction is run in a continuous mode or in a batch mode.
13. The method according to claim 12 , wherein the molar ratio of amide to cellulose reactive agent is in the range of about 2:1 to about 12:1.
14. The method according to claim 12 , wherein the adduct is a reaction product of vinylamide polymer and glyoxal and the vinylamide polymer has an average molecular weight of at least about 30,000 to at least about 5,000,000 wherein at least 40 wt. % of the total cellulose reactive agent is consumed.
15. The method according to claim 12 , which further includes a second polymer in addition to the vinylamide polymer and/or formed adduct.
16. The method according to claim 15 , wherein the second polymer is selected from the group consisting of Mannich base, polyamine, polyethyleneimine, polyamidoamine/epichlorohythin, polyamine epichlorohydrin products, dicyandiamide polymers and cationic starch.
17. The method according to claim 12 , wherein the cellulose reactive agent comprises more than one aldehyde functionality.
18. The method according to claim 12 , wherein the cellulose reactive agent is glyoxal, glutaraldehyde, furan dialdehyde, 2-hydroxyadipaldehyde, succinaldehyde, dialdehyde starch, diepoxy compounds, or combinations thereof.
19. The method according to claim 12 , wherein the vinylamide polymer is a homopolymer or copolymer formed from (meth)acrylamide or a substituted (meth)acrylamide.
20. The method according to claim 12 , wherein the vinylamide polymer is nonionic, cationic, potentially cationic, anionic, potentially anionic, or amphoteric, or combinations thereof.
21. The method according to claim 12 , wherein the vinylamide polymer is cationic and formed from (meth)acrylamide or a substituted (meth)acrylamide and a cationic monomer, wherein the cationic monomer is selected from the group consisting of diallyldialkyl ammonium salts, (diakylamino)alkyl(meth)acrylates acid addition or quaternary salts, 2-vinylpyridines acid addition or quaternary salts, diialkylamino alkyl(meth)acrylamides acid addition or quaternary salts, (p-vinyl(phenyl)-trimethylammonium chloride and 1-methacryloyl-4-methyl piperazine acid addition or quaternary ammonium salts.