Reduced by product polyamine-epihalohydrin resins
View Patent ↗Processes for rendering a polyamine-epihalohydrin resin storage stable, including processes that prepare a storage stable resin and/or processes that treat resins. A composition containing a polyamine-epihalohydrin resin which includes CPD-forming species can be treated with at least one agent under conditions to at least one of inhibit, reduce and remove the CPD-forming species to obtain a reduced CPD-forming resin so that a composition containing the reduced CPD-forming polyamine-epihalohydrin resin when stored for 2 weeks at 50° C., and a pH of about 2.5 to 3.5 contains less than about 250 ppm dry basis of CPD. The invention is also directed to a gelation storage stable reduced CPD-forming resin so that a composition containing the reduced CPD-forming polyamine-epihalohydrin resin, when stored at pH 1 for 24 hours at 50° C. and measured at 24 hours, produces less than about 1000 ppm dry basis of CPD. A paper product containing the storage stable polyaminopolyamide-epihalohydrin resin, when corrected for adding at about a 1 wt % addition level of the polyaminopolyamide-epihalohydrin resin, contains less than about 250 ppb of CPD. Moreover, a resin can be prepared starting from a prepolymer having a low acid number or low concentration of acid end groups. The invention is also directed to papers containing the resins.
1. A process for rendering a polyamine-epihalohydrin wet strength resin storage stable, comprising: treating a composition containing a polyamine-epihalohydrin wet strength resin which includes CPD forming species with at least one enzymatic agent, under conditions to at least one of reduce and remove the CPD-forming species to obtain a gelation storage stable reduced CPD-forming wet strength resin so that a composition containing the reduced CPD-forming polyamine-epihalohydrin wet strength resin, when stored at pH 1 for 24 hours at 50 degree C. and measured at 24 hours, produces less than about 250 ppm dry basis of CPD.
2. The process according to claim 1 , wherein the polyamine-epihalohydrin wet strength resin comprises polyaminopolyamide-epihalohydrin wet strength resin.
3. The process according to claim 1 , wherein, prior to the treating a polyamine-epihalohydrin wet strength resin to obtain a reduced CPD-forming wet strength resin, the wet strength resin is contacted with at least one microorganism, or at least one enzyme isolated from the at least one microorganism, in an amount, and at a pH and temperature effective to dehalogenate residual quantities of organically bound halogen.
4. The process according to claim 1 , wherein, subsequent to the subjecting a polyamine-epihalohydrin wet strength resin to obtain a reduced CPD-forming wet strength resin, the reduced CPD-forming wet strength resin is contacted with at least one microorganism, or at least one enzyme isolated from the at least one microorganism, in an amount, and at a pH and temperature effective to dehalogenate residual quantities of organically bound halogen.
5. The process according to claim 1 , wherein, prior to the treating a polyamine-epihalohydrin wet strength resin to obtain a reduced CPD-forming wet strength resin, the wet strength resin is treated to reduce at least one of epihalohydrins, epihalohydrin hydrolysis by-products and organic halogen bound to the polymer backbone.
6. The process according to claim 1 , wherein, subsequent to the treating a polyamine-epihalohydrin wet strength resin to obtain a reduced CPD-forming wet strength resin, the wet strength resin is treated to reduce at least one of epihalohydrins, epihalohydrin hydrolysis by-products and organic halogen bound to the polymer backbone.
7. The process according to claim 2 , wherein the wet strength resin comprises a wet strength resin formed in a polyaminopolyamide-epihalohydrin reaction having a molar ratio of epihalohydrin to secondary amine group of less than 1.
8. The process according to claim 1 , wherein the reduced CPD-forming wet strength resin is acid stabilized after treatment.
9. The process according to claim 8 , wherein the reduced CPD-forming wet strength resin is acid stabilized at pH from about 2.5 to 4.
10. The process according to claim 1 , wherein the at least one enzymatic agent comprises at least one of esterases, lipases and proteases.
11. The process according to claim 2 , wherein the at least one enzymatic agent comprises at least one of esterases, lipases and proteases.
12. The process according to claim 1 , wherein the at least one enzymatic agent comprises proteases.
13. The process according to claim 1 , wherein the composition containing the reduced CPD forming polyamine-epihalohydrin wet strength resin, when stored at pH 1 for 24 hours at 50 degree C. and measured at 24 hours, produces less than about 50 ppm dry basis of CPD.
14. A paper product treated with wet strength resin produced according to the process according to claim 1 .
15. A reduced CPD-forming wet strength resin produced according to the process of claim 1 .
16. An aqueous composition comprising the reduced CPD-forming wet strength resin produced by the process according to claim 1 .
17. The aqueous composition according to claim 16 , wherein the CPD forming wet strength resin comprises polyalkylene polyamine-epihalohydrin wet strength resin.
18. The process according to claim 1 wherein the CPD-forming species comprises a CPD ester.
19. A process for preparing a paper product, comprising:
treating a composition containing a polyamine-epihalohydrin wet strength resin which includes CPD-forming spades with at least one enzymatic agent, under conditions to at least one of reduce and remove the CPD-forming species to obtain a gelation storage stable reduced CPD-forming wet strength resin, and forming a paper product with the reduced CPD forming polyamine-epihalohydrin wet strength resin, so that a paper product, when corrected for adding at about a 1 wt % addition level of the reduced CPD-forming wet strength resin, contains less than about 250 ppb of CPD.
20. The process according to claim 19 , wherein the paper product contains less than about 50 ppb of CPD.
21. The process according to claim 19 , wherein the polyamine-epihalohydrin wet strength resin comprises polyaminopolyamide-epichlorohydrin wet strength resin.
22. The process according to claim 19 , wherein the at least one enzymatic agent comprises at least one of esterases, lipases end proteases.
23. The process according to claim 19 wherein the CPD-forming species comprises a CPD ester.