Deinking agent

Abstract

Provided is a deinking agent making it possible to improve ink collecting power in the step of flotation and yield high-quality deinked pulp without lowering the yield of pulp. It is a deinking agent comprising an ester of an alkylene oxide-added product of glycerin, its hydroxyl value (OHV), saponification value (SV) and acid value (AV) satisfying the following: OHV/(SV−AV+OHV) ranges from 0 to 0.3.

1 . A deinking agent comprising a compound represented by the following general formula (Y), its hydroxyl value (OHV), saponification value (SV) and acid value (AV) satisfying the following: OHV/(SV−AV+OHV) ranges from 0 to 0.3.  
       X—[O(AO)m-R]n   (Y)  [wherein r is each independently a hydrogen atom or an acyl group having 1 to 24 carbon atoms, provided that at least one of plural r is an acyl group having 8 to 24 carbon atoms, a is an alkylene group having 2 to 4 carbon atoms, a may be the groups wherein the numbers of their carbon atoms are different, and m×n is a numerical number of from 45 to 1000, X is a polyhydric alcohol group, n is a number of 3 to 10 being equivalent the valence of X.    
     
     
         2 . The deinking agent according to  claim 1 , in which the compound is represented by the following general formula (a), its hydroxyl value (OHV), saponification value (SV) and acid value (AV) satisfying the following: OHV/(SV−AV°OHV) ranges from 0 to 0.3,  
       
         
           
           
               
               
           
         
         wherein R 1  to R 3  are each independently a hydrogen atom, or an acyl group having 1 to 24 carbon atoms provided that at least one of R 1  to R 3  is an acyl group having 8 to 24 carbon atoms, A is an alkylene group having 2 to 4 carbon atoms, A may be the groups wherein the numbers of their carbon atoms are different, and a+b+c is a numerical number of from 45 to 1000.  
       
     
     
         3 . The deinking agent according to  claim 2 , in which the hydroxyl value (OHV) of a fraction having a weight average molecular weight of 2000 or more, the saponification value (SV) thereof and the acid value (AV) thereof satisfying the following: OHV/(SV−AV+OHV) ranges from 0 to 0.3.  
     
     
         4 . The deinking agent according to  claim 2 , wherein the compound represented by the general formula (a) is an esterified reactant of a reaction product obtained by adding an alkylene oxide to glycerin or a mixture of glycerin and oil and fat, and a carboxylic acid.  
     
     
         5 . A method of removing ink by using the deinking agent according to any one of  claim 1  or  2  in an ink removing step.  
     
     
         6 . A process for preparing a deinking agent comprising a compound represented by the general formula (Y) as defined in Claim land having the value of OHV/(SV−AV+OHV) in the ranges of from 0 to 0.3 wherein hydroxyl value (OHV), saponification value (SV) and acid value (AV), comprising the step of esterifying an alkylene oxide adduct to a trihydric alcohol or a mixture of a trihydric alcohol with fats and/or oils with a carboxylic acid at a temperature of 100° C. to 260° C.  
     
     
         7 . A process for preparing a deinking agent comprising a compound represented by the general formula (Y) as defined in  claim 1  and having the value of OHV/(SV−AV+OHV) in the ranges of from 0 to 0.5 wherein hydroxyl value (OHV) saponification value (SV) and acid value (AV), comprising the step of esterifying an alkylene oxide adduct to a trihydric alcohol with a carboxylic acid at a temperature of 100° C. to 260° C.  
     
     
         8 . A deinking agent obtained by the process as defined in  claim 7.