Radiation curable composition

Abstract

A radiation curable composition comprising 15 to 85 wt % of at least one solvent comprising ≦20 wt % of water; 5 to 50 wt % of at least one radiation curable material having a Mn in the range of from 50 to 10,000 g/mol; and 10 to 70 wt % of at least one polyurethane having a Mw in the range of from 4,000 to 70,000 g/mol, the polyurethane having 0 to 5 wt % of isocyanate-reactive component(s) bearing ionic or potentially ionic water-dispersing groups and a free isocyanate group content ≦0.5 wt %.

1 . According to the present invention there is provided a radiation curable composition comprising:
 (a) 15 to 85 wt % of at least one solvent comprising ≦20 wt % of water;   (b) 5 to 50 wt % of at least one radiation curable material having a Mn in the range of from 50 to 10,000 g/mol and an average acrylate functionality in the range of from 2 to 6;   (c) 10 to 70 wt % of at least one polyurethane
 (i) having a Mw in the range of from 4,000 to 70,000 g/mol; 
 (ii) having 0 to 1.5 wt % of isocyanate-reactive component(s) bearing ionic or potentially ionic water-dispersing groups; 
 (iii) having a free isocyanate group content <0.5 wt %; and 
   wherein (a), (b) and (c) add up to 100%.   
     
     
         2 . A composition according to  claim 1  wherein the ratio of (b) to (c) is in the range of from 9/91 to 40/60. 
     
     
         3 . A composition according to  claim 1  wherein the solvent (a) comprises 75 wt % of solvents having an evaporation rate 1.0. 
     
     
         4 . A composition according to  claim 1  wherein the radiation curable material (b) is a UV curable material. 
     
     
         5 . A composition according to  claim 1  wherein the polyurethane (c) has a viscosity ≦18,000 mPa s at any solids content in the range of from 20 to 60 wt %, in a solvent comprising ≧70 wt % of at least one solvent having a molecular weight ≦105 g/mol. 
     
     
         6 . A composition according to  claim 1  comprising:
 (a) 15 to 85 wt % of at least one solvent comprising ≦1 wt % of water; 
 (b) 5 to 50 wt % of at least one radiation curable material:
 (i) having a Mn in the range of from 550 to 3500 g/mol; 
 (ii) having an average acrylate function in the range of from 2 to 5; 
 
 (c) 10 to 70 wt % of at least one polyurethane:
 (i) having a Mw in the range of from 6,000 to 55,000 glmol; 
 (ii) having 0 to 1.5 wt % of isocyanate-reactive component(s) bearing ionic or potentially ionic water-dispersing groups; 
 (v) having a non-detectable free isocyanate group content; 
 (vi) having 0 to 0.1 mol of CC bonds per 100 g; and 
 
 wherein (a), (b) and (c) add up to 100%; where the ratio of (b) to (c) is in the range of from 14/86 to 35/65. 
 
     
     
         7 . A composition according to  claim 1  wherein the polyurethane is obtained by the reaction of the components:
 (i) 5 to 50 wt % of at least one polyisocyanate; 
 (ii) 0 to 20 wt % of at least one isocyanate-reactive component having a Mw in the range of from 50 to 200 g/mol; 
 (iii) 0 to 90 wt % of at least one isocyanate-reactive component having a Mw in the range of from 201 to 20,000 g/mol; 
 (iv) 0 to 95 wt % of at least one isocyanate-reactive component not comprised by (ii) or (iii); 
 (v) 0 to 40 wt % of at least one chain-extending and/or chain-terminating component not comprised by (i), (ii), (iii) or (iv); 
 where (i), (ii), (iii), (iv) and (v) add up to 100%; in the presence of a solvent; 
 where the components comprise 0 to 1.5 wt % of isocyanate-reactive component(s) bearing ionic or potentially ionic water-dispersing groups. 
 
     
     
         8 . A composition according to  claim 1  having a solids content in the range of from 25 to 85 wt %. 
     
     
         9 . A composition according to  claim 1  having a resolubility within 30 seconds. 
     
     
         10 . An adhesive comprising a composition according to  claim 1 . 
     
     
         11 . An ink comprising:
 (a) 15 to 84 wt % of at least one solvent comprising ≦20 wt % of water;   (b) 5 to 50 wt % of at least one radiation curable material having an Mn in the range of from 50 to 10,000 g/mol and an average acrylate functionality in the range of from 2 to 6;   (c) 10 to 70 wt % of at least one polyurethane:
 (i) having a Mw in the range of from 4,000 to 70,000 g/mol; 
 (ii) having 0 to 1.5 wt % of isocyanate-reactive component(s) bearing ionic or potentially ionic water-dispersing groups; having a free isocyanate group content ≦0.5 wt %; and 
   (d) 0.1 to 50 wt % of at least one colorant:   wherein (a), (b), (c) and (d) add up to 100%; and   where the ratio of (b) to (c) is in the range of from 9/91 to 40/60.   
     
     
         12 . An ink according to  claim 11  comprising ≦10 wt % of water. 
     
     
         13 . An ink according to  claim 11  having a viscosity in the range of from 50 to 1,000 mPa s. 
     
     
         14 . A process for printing an image on a substrate comprising applying thereto an ink according to  claim 11 . 
     
     
         15 . A flexographic printing process comprising applying an ink according to  claim 11  to a substrate. 
     
     
         16 . A gravure printing process comprising applying an ink according to  claim 11  to a substrate. 
     
     
         17 . A gravure printing process comprising applying an ink according to  claim 12  to a substrate.