Compositions for improving physical strength properties and humidity resistance of paper products

Abstract

Compositions for enhancing the strength and humidity resistance of lignocellulosic fibrous materials such as paper. The compositions are comprised of at least one lignin derivative and a solvent system whereby the solvent system is comprised of water and at least one organic solvent. Suitable lignin derivatives include but are not limited to lignosulfonate, lignosulfonate/kraft lignin, lignosulfonate/organosolv, and mixtures thereof. Sugar may be optionally added to further enhance the strength and humidity resistance of lignocellulosic fibrous materials. Suitable sugars include but are not limited to sucrose, fructose, glucose, ribose, mannose maltose, glucose amine, and mixtures thereof. Other optional strength enhancing materials including but not limited to starch, carboxymethyl cellulose, and mixtures thereof may also be added if desired to provide additional strength and humidity resistance. The strength and humidity resistance of lignocellulosic fibrous materials treated with the compositions of this invention may be further enhanced by the optional application of thermal energy, radiant energy or combinations thereof. The invention also relates to a method of enhancing the strength and humidity resistance of lignocellulosic fibrous materials.

What is claimed is:  
     
         1 . A composition for enhancing the strength and humidity resistance of a lignocellulosic fibrous material, said composition comprising: 
 a) from about 1% to 80% total active solids by weight of the active composition wherein said solids are comprised of a lignin derivative, said lignin derivative selected from the group consisting of lignosulfonate, lignosulfonate/kraft lignin, lignosulfonate/organosolv, and mixtures thereof;    b) a solvent system comprising from about 20% to 99% by weight of the active composition, said solvent system comprising water and at least one organic solvent.    
     
     
         2 . The composition of  claim 1  wherein said organic solvent is selected from the group consisting of alcohol, ketone, aldehyde, ether, and mixtures thereof.  
     
     
         3 . The composition of  claim 2  wherein said organic solvent is selected from the group consisting of ethanol, acetone, and mixtures thereof.  
     
     
         4 . The composition of  claim 3  wherein said organic solvent comprises from about 5% to 80% by weight of the solvent system.  
     
     
         5 . The composition of  claim 1  wherein said total active solids further comprise at least one sugar, the ratio of said lignin derivative to said sugar is from about 5:1 to 1:5 based on the weight of said total active solids.  
     
     
         6 . The composition of  claim 5  wherein said sugar is selected from the group consisting of ribose, mannose, maltose, fructose, glucose, glucose amine, sucrose, and mixtures thereof.  
     
     
         7 . The composition of  claim 6  wherein said sugar is sucrose.  
     
     
         8 . The composition of  claim 1  wherein said total active solids further comprise an additive selected from the group consisting of starch, carboxymethyl cellulose, sodium silicate, xylan, acrylic polymers, vinyl polymers, and mixtures thereof, the ratio of said lignin derivative to said additive is from about 5:1 to 1:5 based on the weight of said total active solids.  
     
     
         9 . The composition of  claim 1  wherein said lignosulfonate is selected from the group consisting of calcium lignosulfonate, sodium lignosulfonate, ammonium lignosulfonate, magnesium lignosulfonate, zinc lignosulfonate, and mixtures thereof.  
     
     
         10 . The composition of  claim 9  wherein said lignosulfonate is calcium lignosulfonate.  
     
     
         11 . The composition of  claim 1  wherein said organic solvent comprises from about 5% to 80% by weight of said solvent system.  
     
     
         12 . The composition of  claim 11  wherein said organic solvent comprises from about 10% to 70% by weight of said solvent system.  
     
     
         13 . A composition for enhancing the strength and humidity resistance of a lignocellulosic fibrous material, said composition comprising: 
 a) from about 1% to 80% total active solids by weight of the active composition wherein said total active solids are comprised of lignosulfonate;    b) a solvent system comprising from about 20% to 99% by weight of said active composition, said solvent system comprising water and at least one organic solvent wherein said organic solvent is selected from the group consisting of acetone, ethanol, or mixtures thereof, said organic solvent comprising from about 5% to 80% of said solvent system by weight.    
     
     
         14 . The composition of  claim 13  wherein said total active solids further comprise sugar, the ratio of said lignosulfonate to said sugar is from about 5:1 to 1:5 based on the weight of said total active solids.  
     
     
         15 . A composition for enhancing the strength and humidity resistance of a lignocellulosic fibrous material, said composition comprising: 
 a) from about 1% to 80% total active solids by weight of the active composition wherein said total active solids are comprised of lignosulfonate and kraft lignin, the ratio of said lignosulfonate to said kraft lignin is from about 5:1 to 1:5 based on the weight of said total active solids;    b) a solvent system comprising from about 20% to 99% by weight of said active composition, said solvent system comprising water and at least one organic solvent wherein said organic solvent is selected from the group consisting of acetone, ethanol, or mixtures thereof, said organic solvent comprising from about 5% to 80% of said solvent system by weight.    
     
     
         16 . The composition of  claim 15  wherein said total active solids further comprise sugar, the ratio of said lignosulfonate to said kraft lignin to said sugar is from about 5:1:3 to about 3:1:5 based on the weight of said total active solids.  
     
     
         17 . A method of enhancing the strength and humidity resistance of a paper product said method comprising the steps of: 
 a) providing a lignocellulosic fibrous material;    b) providing a composition comprised of: 
 i) from about 1% to 80% total active solids by weight of the active composition wherein said solids are comprised of a lignin derivative said lignin derivative selected from the group consisting of lignosulfonate, lignosulfonate/kraft lignin, lignosulfonate/organosolv, and mixtures thereof;  
 ii) a solvent system comprising from about 20% to 99% by weight of said active composition said solvent system comprising water and at least one organic solvent;  
   c) applying said composition to said lignocellulosic fibrous material wherein the addition rate of said composition to said lignocellulosic fibrous material is from about 1% to 80% total active solids based on the weight of dry fiber in said lignocellulosic fibrous material.    
     
     
         18 . The method of  claim 17  further comprising applying thermal energy, radiant energy, or combinations thereof to said lignocellulosic fibrous material.  
     
     
         19 . The method of  claim 17  wherein said total active solids further comprise at least one sugar whereby the ratio of said lignin derivative to said sugar is from about 5:1 to 1:5 based on the weight of said total active solids.