Neutral deinking with a deinking composition comprising a lipase and a fatty acid ester

Abstract

The present invention relates to methods for deinking wastepaper by pulping wastepaper at a pH between 4 and 8.5 in the presence of deinking agents comprising a lipase and a fatty acid ester and removing the thereby dislodged ink particles.

1 . A method for deinking wastepaper comprising the steps of 
 i) pulping the wastepaper at a pH between 4 and 8.5 in the presence of deinking agent comprising a lipase and a fatty acid ester; and    ii) removing the thereby dislodged ink particles.    
     
     
         2 . A method according to  claim 1 , wherein the consistency in step i) is from about 0.5% to about 15%.  
     
     
         3 . A method according to any of the preceding claims, wherein the wastepaper comprises old newspapers (ONP).  
     
     
         4 . A method according to  claim 3 , wherein the amount of ONP constitutes at least 10% by weight of the total amount of wastepaper.  
     
     
         5 . A method according to  claim 4 , wherein the wastepaper consists essentially of ONP.  
     
     
         6 . A method according to any of claims  1 - 2 , wherein the wastepaper comprises waste magazines (WM).  
     
     
         7 . A method according to  claim 6 , wherein the amount of WM constitutes at least 10% by weight of the total amount of wastepaper.  
     
     
         8 . A method according to  claim 7 , wherein the wastepaper consists essentially of WM.  
     
     
         9 . A method according to any of claims  1 - 2 , wherein the wastepaper comprises ONP and WM.  
     
     
         10 . A method according to  claim 9 , wherein the wastepaper comprises 1-60% by weight of WM and 40-99% by weight of ONP.  
     
     
         11 . A method according to any of the preceding claims, wherein the pulping with the deinking agent is carried out at a pH between 4.5 and 8.5.  
     
     
         12 . A method according to any of the preceding claims, wherein the pulping with the deinking agent is carried out at a temperature from 25 to 75° C.  
     
     
         13 . A method according to any of the preceding claims, wherein the fatty acid ester is a methyl ester, an ethyl ester, a n-propyl ester, an isopropyl ester, a n-butyl ester, an isobutyl ester, a sec-butyl ester, a tert-butyl ester, a monoglyceride, a diglyceride or a triglyceride of a C 6 -C 22  fatty acid, the C 6 -C 22  fatty acid being optionally substituted with one or more hydroxy, ethoxy, n-propoxy and/or isopropoxy groups.  
     
     
         14 . A method according to any of claims  1 - 13 , wherein the fatty acid ester is a C 6 -C 22  fatty acid, which has been alkoxylated with ethylene oxide, propylene oxide, or a combination thereof.  
     
     
         15 . A method according to claims  13  or  14 , wherein the fatty acid moiety of the fatty acid ester is selected from the group consisting of caproic acid (6:0), enanthic cid (7:0), caprylic acid (8:0) pelargonic acid (9:0), capric acid (10:0) undecylenic acid (11:0), lauric acid (12:0), tridecylic acid (13:0), myristic acid (14:0), palmitic acid (16:0), stearic acid (18:0), palmitoleic acid (16:1), oleic acid (18:1), elaidic acid (18:1), ricinoleic acid (18:1), linoleic acid (18:2), linolenic acid (18:3) and mixture thereof.  
     
     
         16 . A method according to claims  13  or  14 , wherein the fatty acid moiety of the fatty acid ester is substituted with one or more ethoxy and/or isopropoxy groups.  
     
     
         17 . A method according to  claim 16 , wherein fatty acid moiety of the fatty acid ester is substituted with ethoxy and isopropoxy groups of the general formulae 
 —(O—CH 2 —CH 2 ) x —(O—CH(CH 3 )—CH 2 ) y —OH,    —(O—CH 2 —CH 2 ) x —(O—CH 2 —CH(CH 3 )) y —OH,    —(O—CH(CH 3 )—CH 2 ) y —(O—CH 2 —CH 2 ) x —OH, or    —(O—CH 2 —CH(CH 3 )) y —(O—CH 2 —CH 2 ) x —OH,    wherein x is an integer in the range from 1 to 25, and y is an integer in the range from 1 to 10.    
     
     
         18 . A method according to  claim 17 , wherein x is an integer in the range from 1 to 10, and y is an integer in the range from 1 to 5.  
     
     
         19 . A method according to any of claims  14 - 18 , wherein the fatty acid ester is a triglyceride.  
     
     
         20 . A method according to  claim 19 , wherein the fatty acid ester is Hartaflot G-5000™.  
     
     
         21 . A method according to any of the preceding claims, wherein the pulping step is carried out in the presence of a starch degrading enzyme.  
     
     
         22 . A method according to  claim 21 , wherein the starch degrading enzyme is an amylase.  
     
     
         23 . A method according to any of the preceding claims, wherein the pulping step is carried out in the presence of a cellulase.  
     
     
         24 . A method according to  claim 23 , wherein the cellulase is a mono component cellulase.  
     
     
         25 . A method according to  claim 24 , wherein the cellulase lacks a cellulose binding domain.  
     
     
         26 . A method according to any of the preceding claims, wherein the lipase is added in an amount corresponding to 0.001 - 0.15% by weight of the dry pulp.  
     
     
         27 . A method according to any of the preceding claims, wherein the fatty acid ester is added in an amount corresponding to 0.025 - 1% by weight of the dry pulp.