Water-emulsifiable isocyanates for coatings having an improved gloss

Abstract

The invention relates to new, water-emulsifiable isocyanates, to a process for preparing water-emulsifiable isocyanates, and to the use thereof.

1 : A water-emulsifiable polyisocyanate, comprising:
 an polyisocyanate based on at least one (cyclo)aliphatic diisocyanate,   a compound comprising at least two two isocyanate-reactive groups and at least one selected from the group consisting of a thioether group (—S—), a selanyl group (—Se—), a sulfoxide group (—S(═O)—), and a sulfone group (—S(═O) 2 —),   a compound comprising an isocyanate-reactive group and a dispersive group, and   optionally a solvent;   wherein:
 the ratio of NCO groups in the polyisocynate to isocyanate-reactive groups in the compound comprising at least two isocyanate groups and at least one group selected from the group consisting of a thioether group (—S—), a selanyl group (—Se—), a sulfoxide group (—S(═O)—), and a sulfone group (S(═O) 2 —) and the compound comprising an isocyanate-reactive group and a dispersive group is 5:1 to 100:1, 
 the ethylene oxide group content, calculated as 44 g/mol, based on the sum of the polyisocyanate based on at least one (cyclo)aliphatic diisocyanate, the compound comprising at least two isocyanate groups and at least one group selected from the group consisting of a thioether group (—S—), a selanyl group (—Se—), a sulfoxide group (—S(═O)—), and a sulfone group (—S(═O) 2 —) and the compound comprising an isocyanate-reactive group and a dispersive group is at least 12 wt. %, 
 the amount of the compound comprising an isocyanate-reactive group and a dispersive group, based on the polyisocyanate based on at least one (cyclo)aliphatic diisocyanate, is at least 5 and up to 25 wt. %, and 
 the viscosity at 23° C. to DIN EN ISO 3219/A.3 (October 1994) in a cone/plate system with a shear rate of 1000 s −1  is from 2500 mPas to 12 000 mPas. 
   
     
     
         2 : The water-emulsifiable polyisocyanate according to  claim 1 , wherein the (cyclo)aliphatic diisocyanate is selected from the group consisting of hexamethylene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, isophorone diisocyanate, 4,4′-di(isocyanatocyclohexyl)methane, and 2,4′-di(isocyanatocyclohexyl)methane. 
     
     
         3 : The water-emulsifiable polyisocyanate according to  claim 1 , wherein the polyisocyanate is an isocyanurate of 1,6-hexamethylene diisocyanate. 
     
     
         4 : The water-emulsifiable polyisocyanate according to  claim 1 , wherein the compound comprising at least two isocyanate groups and at least one group selected from the group consisting of a thioether group (—S—), a selanyl group (—Se—), a sulfoxide group (—S(═O)—), and a sulfone group (—S(═O) 2 —) is represented by Formula B1, B2, B3 or B4: 
       
         
           
           
               
               
           
         
         wherein: 
         R 4  and R 5 , independently of one another, are each a radical that is optionally substituted with functional groups, aryl, alkyl, aryloxyl, halogen, a heteroatom and/or a heterocycle, the radical being selected from the group consisting of a C 1 -C 18  alkylene, a C 2 -C 18  alkylene optionally interrupted by one or more oxygen atoms and/or sulfur atoms, a C 6 -C 12  arylene, and a C 5 -C 12  cycloalkyl. 
       
     
     
         5 : The water-emulsifiable polyisocyanate according to  claim 4 , wherein R 4  and R 5 , independently of one another, are selected from the group consisting of 1,2-ethylene, 1,2-propylene, 1,3-propylene, 1,4-butylene, 1,5-pentylene, 1,6-hexylene, 2-methyl-1,3-propylene, 2-ethyl-1,3-propylene, 2,2-dimethyl-1,3-propylene, 2,2-dimethyl-1,4-butylene, 3-oxa-1,5-pentylene, 3,6-dioxa-1,8-octylene, 3,6,9-trioxa-1,11-undecylene, 1,1-, 1,2-, 1,3- or 1,4-cyclohexylene, 1,2- or 1,3-cyclopentylene, 1,2-, 1,3-, or 1,4-phenylene, and 4,4′-biphenylene. 
     
     
         6 : The water-emulsifiable polyisocyanate according to  claim 1 , wherein the compound comprising at least two isocyanate groups and at least one group selected from the group consisting of a thioether group (—S—), a selanyl group (—Se—), a sulfoxide group (—S(═O)—), and a sulfone group (—S(═O) 1 ) is selected from the group consisting of 3-thiapentane-1,5-diol (thiodiglycol), 1,5-dimethyl-3-thiapentane-1,5-diol, 1-methyl-3-thiahexane-1,6-diol, 4-thiaheptane-1,7-diol, and 4,4′-dihydroxydiphenyl sulfide. 
     
     
         7 : The water-emulsifiable polyisocyanate according to  claim 1 , wherein the compound comprising an isocyanate-reactive group and a dispersive group comprises a monoalcohol comprising at least 7 ethylene oxide groups. 
     
     
         8 : The water-emulsifiable polyisocyanate according to  claim 1 , wherein the compound comprising an isocyanate-reactive group and a dispersive group is represented by the formula:
   R 1 —O—[—X i —] k —H;
   wherein:   R 1  is a C 1 -C 18  alkyl, C 2 -C 18  alkyl optionally interrupted by one or more oxygen atoms and/or sulfur atoms, a C 6 -C 12  aryl, a C 5 -C 12  cycloalkyl, or a five- to six-membered heterocycle having oxygen, nitrogen and/or sulfur atoms,   k is an integer from 7 to 30, and   each X i  for i=1 to k, independently of one another, is —CH 2 —CH 2 —O—.   
     
     
         9 : The water-emulsifiable polyisocyanate according to  claim 1 , wherein the compound comprising an isocyanate-reactive group and a dispersive group is represented by the general formula;
   RG-R 6 -DG;   wherein:   RG is at least one isocyanate-reactive group,   DG is at least one dispersive group selected from the group consisting of —COOH, —SO 3 H, —OPO 3 H, —PO 3 H, and an thereof which may be associated with any desired counterion, and   R 6  is an aliphatic, cycloaliphatic, or aromatic radical comprising 1 to 20 carbon atoms.   
     
     
         10 : The water-emulsifiable polyisocyanate according to  claim 1 , wherein the compound comprising an isocyanate-reactive group and a dispersive group selected from the group consisting of mercaptoacetic acid, mercaptopropionic acid, thiolactic acid, mercaptosuccinic acid, glycine, iminodiacetic acid, sarcosine, alanine, β-alanine, leucine, isoleucine, aminobutyric acid, hydroxyacetic acid, hydroxypivalic acid, lactic acid, hydroxysuccinic acid, hydroxydecanoic acid, dimethylolpropionic acid, dimethylolbutyric acid, ethylenediaminetriacetic acid, hydroxydodecanoic acid, hydroxyhexadecanoic acid, 12-hydroxystearic acid, aminobenzenesulfonic acids substituted on the ring by alkyl, aminonaphthalenecarboxylic acid, hydroxyethanesulfonic acid, hydroxypropanesulfonic acid, mercaptoethanesulfonic acid, mercaptopropanesulfonic acid, aminomethanesulfonic acid, taurine,
 aminopropanesulfonic acid, N-alkyl-substituted aminomethanesulfonic acid, cycloalkyl-substituted aminomethanesulfonic acid, aryl-substituted aminomethanesulfonic acid, N-alkyl-substituted aminopropanesulfonic acid, cycloalkyl-substituted aminopropanesulfonic acid, aryl-substituted aminopropanesulfonic acid, an alkali metal thereof, an alkaline earth metal thereof, and an ammonium salt thereof. 
 
     
     
         11 : The water-emulsifiable polyisocyanate according to  claim 1 , wherein the compound comprising an isocyanate-reactive group and a dispersive group is a phosphoric ester represented by the formulae (Ia) or (Ib) or a mixture thereof 
       
         
           
           
               
               
           
         
       
       wherein:
 R 10  and R 11 , independently of one another, are each an alkyl. 
 
     
     
         12 : The water-emulsifiable polyisocyanate according to  claim 11 , wherein R 10  and R 11  have the general formula (II):
 wherein:   R 12  is a C 1  to C 20  alkyl,   n is 0 (zero) or a positive integer from 1 to 20, and   each X i  for i=1 to n, independently of one another, is selected from the group consisting of —CH 2 —CH 2 —O—, —CH 2 —CH(CH 3 )—O—, and —CH(CH 3 )—CH 2 —O—.   
     
     
         13 : A method for coating wood, wood veneer, paper, board, card, textile, leather, nonwoven, plastics surfaces, glass, ceramic, mineral building materials, metals, or coated metals, comprising
 applying the water-emulsifiable polyisocyanate according to  claim 1  to the wood, wood veneer, paper, board, card, textile, leather, nonwoven, plastics surfaces, glass, ceramic, mineral building materials, metals, or coated metals.   
     
     
         14 : A method for crosslinking a polymer, comprising:
 mixing the water-emulsifiable polyisocyanate according to  claim 1  to an aqueous polymer dispersion.