Paper making process and starch compositions comprising a crosslinking agent for use in same

Abstract

The present invention relates to methods for manufacturing paper or paperboard with improved strength and drainage by introduction into the fiber furnish, prior to sheet formation, an aqueous starch dispersion of a gelatinized, self-retaining starch, and an aldehyde generating compound or a glyoxal releasing compound. The present invention further relates to pre-gelatinized starch compositions comprising an aqueous mixture of a pre-gelatinized starch and an aldehyde generating compound or a glyoxal releasing compound.

1 . A method for manufacturing paper or paperboard sheet with increased strength, the method comprising the steps of: 
 providing a fiber slurry suitable for use in making paper or paperboard;    incorporating a gelatinized starch composition into the fiber slurry, wherein the gelatinized starch composition comprises:    gelatinized starch; and    an aldehyde generating compound capable of forming at least two or more covalent bonds to functional groups present in the starch or fiber when the aldehyde generating compound is heated above an activation temperature;    forming the paper or paperboard sheet;    heating the paper or paperboard sheet at a temperature above the activation temperature of the aldehyde generating compound which is sufficient to dry the paper or paperboard sheet.    
     
     
         2 . The method of  claim 1 , wherein a paper sheet is prepared by the method of manufacture.  
     
     
         3 . The method of  claim 1 , wherein a paperboard sheet is prepared by the method of manufacture.  
     
     
         4 . The method of  claim 1 , wherein the starch is self-retaining.  
     
     
         5 . The method of  claim 4 , wherein the starch is a net cationic starch.  
     
     
         6 . The method of  claim 4 , wherein the starch is pregelatinized self-retaining starch selected from potato, corn or wheat starch.  
     
     
         7 . The method of  claim 1 , wherein the gelatinized starch composition comprises between 0.5% to 50% aldehyde generating compound based on the dry weight of the starch and aldehyde generating compound.  
     
     
         8 . The method of  claim 1 , wherein the aldehyde generating compound reacts with starch or gelatinized starch with a rate sufficiently slow to permit storage of the composition for at least one day at room temperature.  
     
     
         9 . The method of  claim 8 , wherein the aldehyde generating compound reacts with starch or gelatinized starch at a sufficiently slow rate to permit storage of the composition for at least one week at room temperature.  
     
     
         10 . The method of  claim 8 , wherein the aldehyde generating compound reacts with starch or gelatinized starch at a sufficiently slow rate to permit storage of the composition for at least three weeks at room temperature.  
     
     
         11 . The method of  claim 1 , wherein the gelatinized starch composition further comprises at least one aldehyde blocking compound capable of blocking aldehyde residues.  
     
     
         12 . The method of  claim 11 , wherein the aldehyde blocking compound loading is at least 10 molar % of the aldehyde generating compound.  
     
     
         13 . The method of  claim 11 , wherein the aldehyde blocking compound is selected from the group consisting of C 1-20 alcohols, C 2-20 alkylene glycols, and C 1-20 alkylamines.  
     
     
         14 . The method of  claim 11 , wherein the aldehyde blocking compound is selected from the group consisting of methanol, ethanol, propanol, ethylene glycol, glycerin, propylene glycol and urea.  
     
     
         15 . The method of  claim 1 , wherein the aldehyde generating compound is a glyoxal releasing compound.  
     
     
         16 . The method of  claim 15 , wherein the glyoxal releasing compound is a reaction product of at least one molar equivalent of glyoxal with between about 0.25 and about 5 molar equivalents of one or more stabilizing agents.  
     
     
         17 . The method of  claim 16 , wherein the glyoxal releasing compound thermally degrades at the temperature sufficient to dry paper or paperboard thereby releasing one or more equivalents of glyoxal.  
     
     
         18 . The method of  claim 17 , wherein the thermally released glyoxal forms crosslinks between two starch moieties or between a starch moiety and fiber by reacting with functional groups of the starch moiety or fiber to form covalent bonds.  
     
     
         19 . The method of  claim 16 , wherein the glyoxal releasing compound is a reaction product of 
 at least one molar equivalent of glyoxal; and    between about 0.5 and about 5 molar equivalents of stabilizing agents selected from the group consisting of optionally substituted urea, optionally substituted thiourea, optionally substituted imidazolidin-2-one, and optionally substituted tetrahydro-pyrimidin-2-one.    
     
     
         20 . The method of  claim 11 , wherein the aldehyde generating compound is a reaction product of 
 at least one molar equivalent of glyoxal; and    between about 1 and about 3 molar equivalent of stabilizing agents selected from the group consisting of urea, thiourea, 4,5-dihydroxy-imidazolidin-2-one, and 4-hydroxy-5-(C 1-10 -alkyl)-tetrahydro-pyrimidin-2-one.    
     
     
         21 . The method of  claim 19 , wherein the glyoxal releasing compound is a compound according to Formula I:  
       
         
           
           
               
               
           
         
         wherein  
         A is an optionally substituted methylene group, an optionally substituted C 2-4 alkylene group, or a single bond;  
         B is carbonyl, thiocarbonyl, or an optionally substituted 1,2-ethylene residue;  
         X 1  and X 2  are independently selected from the group consisting of oxygen and NR 3 ;  
         R 1  and R 2  are independently selected from the group consisting of hydrogen, hydroxyl, optionally substituted C 1-20 alkyl, optionally substituted C 1-20 alkoxy, optionally substituted urea, optionally substituted thiourea, or  
         R 1  and R 2 , taken in combination, form a N,N′-divalent urea;  
         R 3  is independently selected at each occurrence of R 3  from the group consisting of hydrogen, optionally substituted C 1-20 alkyl, and blocked glyoxal residues, where the blocked glyoxal residue is a 1-hydroxy-2-(protected aldehyde residue)-ethan-1-yl group; and  
         wherein the aldehyde generating compound according to Formula I thermally degrades to generate at least one equivalent of glyoxal when heated above an activation temperature.  
       
     
     
         22 . The method of  claim 21 , wherein the aldehyde generating compound is a glyoxal releasing compound.  
     
     
         23 . The method of  claim 22 , wherein 
 R 1  and R 2  are independently selected from the group consisting of hydrogen, hydroxyl, methanol, ethanol, urea, or    R 1  and R 2 , taken in combination, form a N,N′-divalent urea;    R 3  is independently selected at each occurrence of R 3  from the group consisting of hydrogen, methyl, and ethyl, or    R 3  is a blocked glyoxal residue selected from the group consisting of 1,2-dihydroxy-2-(C 1-4 -alkoxy)-ethan-1-yl, 1,2-dihydroxy-2-(3-hydroxypropoxy)-ethan-1-yl, and 1,2-dihydroxy-2-(2-hydroxypropoxy)-ethan-1-yl.    
     
     
         24 . The method of  claim 22 , wherein 
 X 1  and X 2  are NR 3 ;    A is a single bond;    B is a carbonyl or thiocarbonyl group; and    R 1  and R 2  are independently selected from hydroxyl, C 1-6 -alkoxy, or blocked glyoxal residues.    
     
     
         25 . The method of  claim 22 , wherein 
 X 1  and X 2  are NR 3 ;    A is a 1,1-C 1-6 alkylene group;    B is a carbonyl or thiocarbonyl group;    R 1  and R 2  are independently selected from hydrogen, hydroxyl, C 1-6 -alkoxy, or blocked glyoxal residues; and    R 3  is a blocked glyoxal residue selected from the group consisting of 1,2-dihydroxy-2-(C 1-4 -alkoxy)-ethan-1-yl, 1,2-dihydroxy-2-(3-hydroxypropoxy)-ethan-1-yl, and 1,2-dihydroxy-2-(2-hydroxypropoxy)-ethan-1-yl.    
     
     
         26 . The method of  claim 22 , wherein the glyoxal releasing compound comprises at least one compound selected from the group consisting of compounds of the formulae:  
       
         
           
           
               
               
           
         
       
     
     
         27 . The method of  claim 1 , wherein the gelatinized starch composition further comprises a cationic starch containing at least one ammonium salt.  
     
     
         28 . A gelatinized starch composition for use strengthening paper or paperboard, the composition comprising: 
 a self-retaining gelatinized starch;    at least one aldehyde blocking compound capable of blocking aldehyde residues; and    an aldehyde generating compound according to the Formula I:                          wherein    A is an optionally substituted methylene group, an optionally substituted C 2-4 alkylene group, or a single bond;    B is carbonyl, thiocarbonyl, or an optionally substituted 1,2-ethylene residue;    X 1  and X 2  are independently selected from the group consisting of oxygen and. NR 3 ;    R 1  and R 2  are independently selected from the group consisting of hydrogen, hydroxyl, optionally substituted C 1-20 alkyl, optionally substituted C 1-20 alkoxy, optionally substituted urea, optionally substituted thiourea, or    R 1  and R 2 , taken in combination, form a N,N′-divalent urea;    R 3  is independently selected at each occurrence of R 3  from the group consisting of hydrogen, optionally substituted C 1-20 alkyl, and blocked glyoxal residues, where the blocked glyoxal residue is a 1-hydroxy-2-(protected aldehyde residue)-ethan-1-yl group;    wherein the aldehyde generating compound according to Formula I thermally degrades to generate at least one equivalent of aldehyde when heated above an activation temperature; and    wherein the aldehyde blocking compound loading is at least 10 molar % of the aldehyde generating compound.    
     
     
         29 . The gelatinized starch composition of  claim 28 , wherein the aldehyde generating compound is a glyoxal releasing compound.  
     
     
         30 . The gelatinized starch composition of  claim 29 , wherein the glyoxal releasing compound reacts with starch or gelatinized starch with a rate sufficiently slow to permit storage of the composition for at least one day at room temperature.  
     
     
         31 . The gelatinized starch composition of  claim 29 , wherein the glyoxal releasing compound reacts with starch or gelatinized starch at a sufficiently slow rate to permit storage of the composition for at least one week at room temperature.  
     
     
         32 . The gelatinized starch composition of  claim 29 , wherein the glyoxal releasing compound reacts with starch or gelatinized starch at a sufficiently slow rate to permit storage of the composition for at least three weeks at room temperature.  
     
     
         33 . The gelatinized starch composition of  claim 29 , wherein the glyoxal releasing compound is capable of forming at least two or more covalent bonds to functional groups present in the starch or fiber when the glyoxal releasing compound is heated above an activation temperature.  
     
     
         34 . The gelatinized starch composition of  claim 29 , wherein the starch is a cationic starch.  
     
     
         35 . The gelatinized starch composition of  claim 29 , wherein the starch is selected from potato, corn or wheat starch.  
     
     
         36 . The gelatinized starch composition of  claim 29 , wherein the aldehyde blocking compound is selected from the group consisting of C 1-20 alcohols, C 2-20 alkylene glycols, and C 1-20 alkylamines.  
     
     
         37 . The gelatinized starch composition of  claim 29 , wherein the aldehyde blocking compound is selected from the group consisting of methanol, ethanol, propanol, ethylene glycol, and propylene glycol.  
     
     
         38 . The gelatinized starch composition of  claim 29 , wherein 
 R 1  and R 2  are independently selected from the group consisting of hydrogen, hydroxyl, methanol, ethanol, urea, or    R 1  and R 2 , taken in combination, form a N,N′-divalent urea;    R 3  is independently selected at each occurrence of R 3  from the group consisting of hydrogen, methyl, and ethyl, or    R 3  is a blocked glyoxal residue selected from the group consisting of 1,2-dihydroxy-2-(C 1-4 -alkoxy)-ethan-1-yl, 1,2-dihydroxy-2-(3-hydroxypropoxy)-ethan-1-yl, and 1,2-dihydroxy-2-(2-hydroxypropoxy)-ethan-1-yl.    
     
     
         39 . The gelatinized starch composition of  claim 29 , wherein 
 X 1  and X 2  are NR 3 ;    A is a single bond;    B is a carbonyl or thiocarbonyl group; and    R 1  and R 2  are independently selected from hydroxyl, C 1-6 alkoxy, or stabilized glyoxal residues.    
     
     
         40 . The gelatinized starch composition of  claim 29 , wherein 
 X 1  and X 2  are NR 3 ;    A is a 1,1-C 1-6 alkylene group;    B is a carbonyl or thiocarbonyl group;    R 1  and R 2  are independently selected from hydrogen, hydroxyl, C 1-6 alkoxy, or stabilized glyoxal residues; and    R 3  is a blocked glyoxal residue selected from the group consisting of 1,2-dihydroxy-2-(C 1-4 -alkoxy)-ethan-1-yl, 1,2-dihydroxy-2-(3-hydroxypropoxy)-ethan-1-yl, and 1,2-dihydroxy-2-(2-hydroxypropoxy)-ethan-1-yl.    
     
     
         41 . The gelatinized starch composition of  claim 29 , wherein the glyoxal releasing compound comprises at least one compound selected from the group consisting of is compounds of the formulae: