Sizing dispersion

Abstract

The present invention refers to an aqueous sizing dispersion comprising a ketene dimer based sizing agent, wherein the sizing agent is obtained by (i) providing a mixture of fatty acid halides comprising saturated fatty acid halides having 12 and 16 carbon atoms, the amount of fatty acid halides having 16 carbon atoms being from 20 up to 500 molar % based on total amount of fatty acids having 12 carbon atoms, and (ii) removal of hydrogen halide from the saturated fatty acid halides thereby forming ketene dimer. Furthermore, the invention also includes a process for the production of paper comprising adding the aqueous dispersion to a cellulosic suspension, forming and dewatering the suspension on a wire.

1 . An aqueous sizing dispersion comprising a ketene dimer based sizing agent, wherein the sizing agent is obtained by 
 (i) providing a mixture of fatty acid halides comprising saturated fatty acid halides having 12 and 16 carbon atoms, the amount of fatty acid halides having 16 carbon atoms being from 20 up to 500 molar % based on total amount of fatty acids having 12 carbon atoms, and    (ii) removal of hydrogen halide from the saturated fatty acid halides thereby forming ketene dimer.    
     
     
         2 . The dispersion according to  claim 1 , wherein the amount of fatty acid halides having 16 carbon atoms is from 30 up to 300 molar % based on the total amount of fatty acid halides having 12 carbon atoms.  
     
     
         3 . The dispersion according to  claim 1 , wherein said dispersion comprises a cationic polysaccharide in an amount from about 0.1 up to 50% by weight based on sizing agent.  
     
     
         4 . The dispersion according to  claim 3 , wherein the cationic polysaccharide is cationic starch having a cationic substitution (DS c ) from about 0.01 up to about 0.2.  
     
     
         5 . The dispersion according to  claim 1 , wherein said dispersion comprises a cationic polysaccharide in an amount from about 0.1 up to 50% by weight based on sizing agent and a naphthalene sulphonate condensation polymer in an amount from about 0.1 up to 50% by weight based on sizing agent.  
     
     
         6 . An aqueous sizing dispersion comprising an amount of from about 5 up to about 50% by weight of a ketene dimer based sizing agent, wherein the sizing agent is obtained by 
 (i) providing a mixture of fatty acid halides comprising saturated fatty acid halides having 12, 14 and 16 carbon atoms, the amount of fatty acid halides having 16 carbon atoms being from 30 up to 300 molar % based on total amount of fatty acid halides having 12 carbon atoms, the amount of saturated fatty acid halides having 14 carbon atoms being from about 45 up to about 400 molar %, and    (ii) removal of hydrogen halide from the saturated fatty acid halides thereby forming ketene dimer.    
     
     
         7 . The dispersion according to  claim 6 , wherein said dispersion comprises a cationic polysaccharide in an amount from about 0.1 up to 50% by weight based on sizing agent.  
     
     
         8 . The dispersion according to  claim 7 , wherein the cationic polysaccharide is cationic starch having a cationic substitution (DS c ) from about 0.01 up to about 0.2.  
     
     
         9 . The dispersion according to  claim 6 , wherein said dispersion comprises a cationic polysaccharide in an amount from about 0.1 up to 50% by weight based on sizing agent and a naphthalene sulphonate condensation polymer in an amount from about 0.1 up to 50% by weight based on sizing agent.  
     
     
         10 . An aqueous sizing dispersion comprising an amount of from about 5 up to about 50% by weight of a ketene dimer based sizing agent, wherein the sizing agent is obtained by 
 (i) providing a mixture of fatty acid halides comprising saturated fatty acid halides having 12, 14 and 16 carbon atoms, the amount of fatty acid halides having 16 carbon atoms being from 30 up to 300 molar % based on amount of fatty acid halides having 12 carbon atoms, the amount of saturated fatty acid halides having 14 carbon atoms being from about 45 up to about 400 molar % based on amount of fatty acid halides having 12 carbon atoms, the amount of fatty acid halides having 12 carbon atoms being up to about 45% by weight based on total fatty acid halides in the mixture, and    (ii) removal of hydrogen halide from the saturated fatty acid halides thereby forming ketene dimer.    
     
     
         11 . The dispersion according to  claim 10 , wherein said dispersion comprises a cationic polysaccharide in an amount from about 0.1 up to 50% by weight based on sizing agent.  
     
     
         12 . The dispersion according to  claim 11 , wherein the cationic polysaccharide is cationic starch having a cationic substitution (DS c ) from about 0.01 up to about 0.2.  
     
     
         13 . The dispersion according to  claim 10 , wherein said dispersion comprises a cationic polysaccharide in an amount from about 0.1 up to 50% by weight based on sizing agent and a naphthalene sulphonate condensation polymer in an amount from about 0.1 up to 50% by weight based on sizing agent.  
     
     
         14 . An aqueous sizing dispersion comprising an amount of from about 5 up to about 50% by weight of a ketene dimer based sizing agent, wherein the sizing agent is obtained by 
 (i) providing a mixture of fatty acid halides comprising saturated fatty acid halides having 12, 14 and 16 carbon atoms, the amount of fatty acid halides having 16 carbon atoms being from 30 up to 300 molar % based on amount of fatty acid halides having 12 carbon atoms, the amount of saturated fatty acid halides having 14 carbon atoms being from about 45 up to about 400 molar % based on amount of fatty acid halides having 12 carbon atoms, the amount of fatty acid halides having 12 carbon atoms being up to about 45% by weight based on total fatty acid halides in the mixture, the reaction mixture being essentially free from unsaturated fatty acid halides and branched fatty acid halides, and    (ii) removal of hydrogen halide from the saturated fatty acid halides thereby forming ketene dimer.    
     
     
         15 . The dispersion according to  claim 14 , wherein said dispersion comprises a cationic polysaccharide in an amount from about 0.1 up to 50% by weight based on sizing agent.  
     
     
         16 . The dispersion according to  claim 15 , wherein the cationic polysaccharide is cationic starch having a cationic substitution (DS c ) from about 0.01 up to about 0.2.  
     
     
         17 . The dispersion according to  claim 14 , wherein said dispersion comprises a cationic polysaccharide in an amount from about 0.1 up to 50% by weight based on sizing agent and a naphthalene sulphonate condensation polymer in an amount from about 0.1 up to 50% by weight based on sizing agent.  
     
     
         18 . A process for the production of paper comprising adding an aqueous sizing dispersion comprising a ketene dimer based sizing agent, wherein the sizing agent is obtained by 
 (i) providing a mixture of fatty acid halides comprising saturated fatty acid halides having 12 and 16 carbon atoms, the amount of fatty acid halides having 16 carbon atoms being from 20 up to 500 molar % based on total amount of fatty acids having 12 carbon atoms, and    (ii) removal of hydrogen halide from the saturated fatty acid halides thereby forming ketene dimer,    to a cellulosic suspension, forming and dewatering the suspension on a wire.