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;   (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 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 any one of the preceding claims wherein the radiation curable material (b) is a UV curable material. 
   
   
       5 . A composition according to any one of the preceding claims wherein the radiation curable material (b) has an average acrylate functionality in the range of from 1 to 6. 
   
   
       6 . A composition according to any one of the preceding claims 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. 
   
   
       7 . A composition according to any one of the preceding claims 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 g/mol; 
 (ii) having 0 to 5 wt % of isocyanate-reactive component(s) bearing ionic or potentially ionic water-dispersing groups; 
 (iii) having a non-detectable free isocyanate group content; 
 (iv) having 0 to 0.1 mol of C═C 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. 
   
   
       8 . A composition according to any one of the preceding claims 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 5 wt % of isocyanate-reactive component(s) bearing ionic or potentially ionic water-dispersing groups. 
   
   
       9 . A composition according to any one of the preceding claims having a solids content in the range of from 25 to 85 wt %. 
   
   
       10 . A composition according to any one of the preceding claims having a resolubility within 30 seconds. 
   
   
       11 . An adhesive comprising a composition according to any one of the preceding claims. 
   
   
       12 . 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;   (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 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. 
   
   
       13 . An ink according to  claim 12  comprising ≦10 wt % of water. 
   
   
       14 . An ink according to  claim 12  having a viscosity in the range of from 50 to 1,000 mPa·s. 
   
   
       15 . A process for printing an image on a substrate comprising applying thereto an ink according to any one of  claims 12  to  14 . 
   
   
       16 . A flexographic printing process comprising applying an ink according to any one of  claims 12  to  14  to a substrate. 
   
   
       17 . A gravure printing process comprising applying an ink according to any one of  claims 12  to  14  to a substrate.