Use of non-thermosetting polyamidoamines as dry-strength resins

Abstract

The invention relates to a process for utilizing resins useful for imparting dry-strength to paper without substantially increasing the paper's wet-strength wherein the resins comprise non-thermosetting crosslinked polyamidoamine-epihalohydrin resins. The invention also relates to the paper produced containing the resins.

1 . A process for manufacturing paper having dry strength comprising the following steps, 
 (a) forming an aqueous suspension of cellulose fibers;    (b) adding a non-thermosetting crosslinked polyamidoamine-epihalohydrin resin to the aqueous suspension of cellulose fibers; and    (c) sheeting and drying the aqueous suspension of cellulose fibers to form paper,    wherein the non-thermosetting crosslinked polyamidoamine-epihalohydrin resin comprises a reaction product of a polyamidoamine and an epihalohydrin and wherein the epihalohydrin to amine is in a ratio of less than 0.10:1 on a molar basis and, and wherein the polyamidoamine has a molecular weight as measured by its reduced specific viscosity (RSV) of greater than 0.13 dL/g prior to reaction with the epihalohydrin.    
     
     
         2 . The process for manufacturing paper of  claim 1 , wherein the polyamidoamine comprises a polyalkylene polyamine having at least two primary amine groups and also at least one secondary and/or at least one tertiary amine group.  
     
     
         3 . The process for manufacturing paper of  claim 2 , wherein the polyalkylene polyamine has two primary amine groups and also at least one secondary and/or at least one tertiary amine group.  
     
     
         4 . The process for manufacturing paper of  claim 2 , wherein the polyamidoamine is selected from the group consisting of diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), iminobispropylamine (IBPA), N-methyl-bis-(aminopropyl)amine (MBAPA), bis-hexamethylenetriamine (BHMT) and mixtures thereof.  
     
     
         5 . The process for manufacturing paper of  claim 2 , wherein the polyamidoamine is diethylenetriamine (DETA).  
     
     
         6 . The process for manufacturing paper of  claim 2 , wherein the polyamidoamine comprises a mixture of diethylenetriamine (DETA) and triethylenetetramine (TETA).  
     
     
         7 . The process for manufacturing paper of  claim 2 , wherein the polyamidoamine comprises a mixture of diethylenetriamine (DETA) and tetraethylenepentamine (TEPA).  
     
     
         8 . The process for manufacturing paper of  claim 1 , wherein the epihalohydrin is selected from the group consisting of epichlorohydrin, epibromohydrin, epiiodohydrin, epifluorohydrin and alkyl-substituted epihalohydrins.  
     
     
         9 . The process for manufacturing paper of  claim 1 , wherein the epihalohydrin is epichlorohydrin.  
     
     
         10 . The process for manufacturing paper of  claim 1 , wherein the polyamidoamine has a molecular weight as measured by its reduced specific viscosity (RSV) of greater than 0.13 dL/g but less than 0.19 dL/g prior to reaction with the epihalohydrin.  
     
     
         11 . The process for manufacturing paper of  claim 8 , wherein the polyamidoamine has a molecular weight as measured by its reduced specific viscosity (RSV) of greater than 0.15 dL/g but less than 0.18 dL/g prior to reaction with the epihalohydrin.  
     
     
         12 . The process for manufacturing paper of  claim 1 , wherein the epihalohydrin to amine is in a ratio in the range of about 0.01:1 to less than 0.10:1 on a molar basis.  
     
     
         13 . The process for manufacturing paper of  claim 11 , wherein the epihalohydrin to amine is in a ratio in the range of about 0.03:1 to about 0.08:1 on a molar basis.  
     
     
         14 . The process for the manufacturing paper of  claim 12 , wherein the epihalohydrin to amine is in a ratio in the range of about 0.05:1 to about 0.07:1 on a molar basis.  
     
     
         15 . The process for the manufacturing paper of  claim 6 , wherein the epihalohydrin to amine is in a ratio in the range of about 0.05:1 to about 0.07:1 on a molar basis, and wherein the epihalohydrin is epichlorohydrin.  
     
     
         16 . The process for manufacturing paper of any one of  claim 1  wherein the non-thermosetting crosslinked polyamidoamine-epihalohydrin resin is added to the aqueous suspension of cellulose fibers in an amount based on about 0.1 to 2% dry-weight of the cellulose fibers.  
     
     
         17 . The process for manufacturing paper of  claim 16 , wherein the non-thermosetting crosslinked polyamidoamine-epihalohydrin resin is added to the aqueous suspension of cellulose fibers in an amount based on about 0.15% dry-weight of the cellulose fibers.  
     
     
         18 . Paper made by the process of any one of claims  1 - 18 .