Solvent Borne Polyurethane Process

Abstract

A process for obtaining a solvent borne polyurethane composition comprising preparing an isocyanate-terminated prepolymer A; reacting the isocyanate groups of isocyanate-terminated prepolymer A with 0.1 to 1.8 stoichiometric equivalents of at least one active-hydrogen containing chain terminating compound and or chain-extending compound; optionally introducing an isocyanate-terminated compound B; and reacting the isocyanate groups of the isocyanate-terminated prepolymer obtained in the previous steps and isocyanate-terminated compound B with 0 to 1.2 stoichiometric equivalents of at least one active-hydrogen containing chain-terminating compound and or chain-extending compound.

1 .- 19 . (canceled) 
   
   
       20 . A process for obtaining a solvent borne polyurethane composition comprising 80 to 25 wt % of a liquid medium, where the liquid medium comprises <20 wt % of water and where the PDi of the solvent borne polyurethane is in the range of from 2.8 to 6, the process comprising the following steps:
 1) preparing an isocyanate-terminated prepolymer A;   2a) reacting the isocyanate groups of isocyanate-terminated prepolymer A with 0 to 0.95 stoichiometric equivalents of at least one active-hydrogen containing chain-terminating compound selected from the group consisting of mono-alcohols, amino-alcohols, primary or secondary amines and mono-functional hydrazines;   2b) reacting the isocyanate groups of isocyanate-terminated prepolymer A with 0 to 0.95 stoichiometric equivalents of at least one active-hydrogen containing chain-extending compound; where steps 2a) and 2b) together are in the range of from 0.1 to 1.8 stoichiometric equivalents;   3) optionally introducing an isocyanate-terminated compound B;   4a) reacting the isocyanate groups of the isocyanate-terminated prepolymer obtained in steps 2a) and 2b) and isocyanate groups of the isocyanate-terminated compound B introduced in step 3) with 0 to 1.0 stoichiometric equivalents of at least one active-hydrogen containing chain-terminating compound selected from the group consisting of mono-alcohols, amino-alcohols, primary or secondary amines and mono-functional hydrazines;   4b) reacting the isocyanate groups of the isocyanate-terminated prepolymer obtained in steps 2a) and 2b) and the isocyanate groups of the isocyanate-terminated compound B introduced in step 3) with 0 to 1.2 stoichiometric equivalents of at least one active-hydrogen containing chain-extending compound;   where steps 4a) and 4b) together are in the range of from 0 to 1.2 stoichiometric equivalents;   where the process comprises at least one step with an active-hydrogen containing chain-extending compound and at least one step with an active-hydrogen containing chain-terminating compound;   where if 0 wt % of the isocyanate-terminated compound B is introduced then step 2a) comprises 0.1 to 0.95 stoichiometric equivalents of at least one active-hydrogen containing chain-terminating compound and at least a step 2a) is performed before a step 2b).   
   
   
       21 . A process for obtaining a solvent borne polyurethane composition comprising the following steps:
 1) preparing an isocyanate-terminated prepolymer A;   2a) reacting the isocyanate groups of isocyanate-terminated prepolymer A with 0 to 0.95 stoichiometric equivalents of at least one active-hydrogen containing chain-terminating compound;   2b) reacting the isocyanate groups of isocyanate-terminated prepolymer A with 0 to 0.95 stoichiometric equivalents of at least one active-hydrogen containing chain-extending compound;   where steps 2a) and 2b) together are in the range of from 0.1 to 1.8 stoichiometric equivalents;   3) optionally introducing an isocyanate-terminated compound B;   4a) reacting the isocyanate groups of the isocyanate-terminated prepolymer obtained in steps 2a) and 2b) and isocyanate groups of the isocyanate-terminated compound B introduced in step 3) with 0 to 1.0 stoichiometric equivalents of at least one active-hydrogen containing chain-terminating compound;   4b) reacting the isocyanate groups of the isocyanate-terminated prepolymer obtained in steps 2a) and 2b) and the isocyanate groups of the isocyanate-terminated compound B introduced in step 3) with 0 to 1.2 stoichiometric equivalents of at least one active-hydrogen containing chain-extending compound;   where steps 4a) and 4b) together are in the range of from 0 to 1.2 stoichiometric equivalents;   where the process comprises at least one step with an active-hydrogen containing chain-extending compound and at least one step with an active-hydrogen containing chain-terminating compound.   
   
   
       22 . A process according to  claim 20  where steps 2a) and 2%) together are in the range of from 0.2 to 0.95 stoichiometric equivalents. 
   
   
       23 . A process according to  claim 20  where step 3 comprises introducing 0 to 1600% by weight of isocyanate-terminated prepolymer A of an isocyanate-terminated compound B. 
   
   
       24 . A process according to  claim 20  where the Mp of the solvent borne polyurethane is in the range of from 6,000 to 60,000 g/mol. 
   
   
       25 . A process according to  claim 21  where the PDi of the solvent borne polyurethane is in the range of from 1.3 to 10. 
   
   
       26 . A process according to  claim 20  where the Mp of the solvent borne polyurethane is in the range of from 6,000 to 60,000 g/mol and the PDi is in the range of from 2.8 to 6. 
   
   
       27 . A process according to  claim 20  where isocyanate-terminated prepolymer A is obtained by reacting components comprising: (i) 8 to 45 wt % of at least one polyisocyanate;
 (ii) 0 to 5 wt % of at least one isocyanate-reactive polyol with a weight-average molecular weight in the range of from 50 to 200 g mol;   (iii) 40 to 92 wt % of at least one isocyanate-reactive polyol with a weight-average molecular weight in the range of from 201 to 20,000 g/mol; and   (iv) 0 to 3 wt % of an isocyanate-reactive polyol not comprised by (ii) or (iii); where (i), (ii), (iii) and (iv) add up to 100%; optionally in the presence of a liquid medium.   
   
   
       28 . A process according to  claim 20  where isocyanate-terminated compound B is at least one polyisocyanate. 
   
   
       29 . A process according to  claim 20  where isocyanate-terminated compound B is at least one isocyanate-terminated prepolymer B. 
   
   
       30 . A process according to  claim 29  where isocyanate-terminated prepolymer B is obtained by reacting components comprising:
 (i) 8 to 45 wt % of at least one polyisocyanate;   (ii) 0 to 5 wt % of at least one isocyanate-reactive polyol with a weight-average molecular weight in the range of from 50 to 200 g/mol; (iii) 40 to 92 wt % of at least one isocyanate-reactive polyol with a weight-average molecular weight in the range of from 201 to 20,000 g/mol; and   (iv) 0 to 3 wt % of an isocyanate-reactive polyol not comprised by (ii) or (iii); where (i), (ii), (iii) and (iv) add up to 100%; optionally in the presence of a liquid medium.   
   
   
       31 . A process according to any  claim 27  where the liquid medium comprises <20 wt % of water. 
   
   
       32 . A process according to  claim 20  where the solvent borne polyurethane composition has a viscosity <5,000 mPa-s at any solids content in the range of from 45 to 75 wt % in a solvent comprising >70 wt % of at least one solvent having an evaporation rate of >1.0. 
   
   
       33 . An ink comprising a solvent borne polyurethane composition obtained by a process according to  claim 20 , a colorant and optionally an additional organic solvent. 
   
   
       34 . An ink comprising a solvent borne polyurethane composition, a colorant and optionally an additional organic solvent, wherein the solvent borne polyurethane composition is obtained by a process comprising the following steps:
 1) preparing an isocyanate-terminated prepolymer A;   2a) reacting the isocyanate groups of isocyanate-terminated prepolymer A with 0 to 0.95 stoichiometric equivalents of at least one active-hydrogen containing chain-terminating compound;   2b) reacting the isocyanate groups of isocyanate-terminated prepolymer A with 0 to 0.95 stoichiometric equivalents of at least one active-hydrogen containing chain-extending compound;   where steps 2a) and 2b) together are in the range of from 0.1 to 1.8 stoichiometric equivalents;   3) optionally introducing an isocyanate-terminated compound B;   4a) reacting the isocyanate groups of the isocyanate-terminated prepolymer obtained in steps 2a) and 2b) and isocyanate groups of the isocyanate-terminated compound B introduced in step 3) with 0 to 1.0 stoichiometric equivalents of at least one active-hydrogen containing chain-terminating compound;   4b) reacting the isocyanate groups of the isocyanate-terminated prepolymer obtained in steps 2a) and 2b) and the isocyanate groups of the isocyanate-terminated compound B introduced in step 3) with 0 to 1.2 stoichiometric equivalents of at least one active-hydrogen containing chain-extending compound;   where steps 4a) and 4b) together are in the range of from 0 to 1.2 stoichiometric equivalents;   where the process comprises at least one step with an active-hydrogen containing chain-extending compound and at least one step with an active-hydrogen containing chain-terminating compound.   
   
   
       35 . An ink according to  claim 33  having a viscosity in the range of from 10 to 100 seconds when measured using a Ford Cup 4 at 20° C. 
   
   
       36 . A method for printing an image on a substrate comprising applying an ink according to  claim 33 . 
   
   
       37 . Use of an ink according to  claim 33  in a flexographic printing processes. 
   
   
       38 . Use of an ink according to  claim 33  in a gravure printing processes. 
   
   
       39 . A laminate comprising a substrate printed with an ink according to  claim 33 .