Low NMP aqueous polyurethane composition with a diluent

An aqueous composition with a sediment content <5%, comprising a polyurethane vinyl hybrid dispersion and containing <0.5 wt % of 1-methyl-2-pyrrolidinone by weight of the composition;

• wherein the polyurethane has an acid value in the range of from to 18 to 65 mgKOH/g and is obtained by the reaction of:
• A) an isocyanate-terminated prepolymer formed from components comprising:
• (i) 36 to 60 wt % of a mixture of toluene diisocyanate and methylene bis(phenyl isocyanate), wherein the mixture comprises 90 to 30 wt % of the methylene bis(phenyl isocyanate)
• (ii) 0 to 30 wt % of at least one aliphatic polyisocyanate;
• (iii) 0 to 15 wt % of at least one isocyanate-reactive polyol bearing ionic and/or potentially ionic water-dispersing groups with a weight average molecular weight <500 g/mol;
• (iv) 0 to 10 wt % of at least one isocyanate-reactive polyol bearing non-ionic water-dispersing groups;
• (v) 0 to 15 wt % of at least one isocyanate-reactive polyol with a weight average molecular weight <500 g/mol not comprised by (iii) or (iv);
• (vi) 20 to 58 wt % of at least one isocyanate-reactive polyol not comprised by (iii), (iv) or (v);
• where (i)+(ii)+(iii)+(iv)+(v)+(vi) add up to 100 wt %;
• where the NCO/OH ratio is in the range of from 1.2:1 to 2.5:1;
• and
• B) at least one active-hydrogen chain extending compound;
• where the active-hydrogen/NCO ratio is in the range of from 0.4:1 to 1.3:1;
• in the presence of (a) <5 wt % of 1-methyl-2-pyrrolidinone by weight of polyurethane, (b) at least one diluent, where the diluent comprises between 5 and 40% by weight of both the isocyanate-terminated prepolymer and the diluent together, and (c) water.

A process for making an aqueous composition with a sediment content <5%, comprising a polyurethane dispersion and containing <5 wt % of 1-methyl-2-pyrrolidinone by weight of the polyurethane, wherein the polyurethane has an acid value in the range of from 18 to 65 mgKOH/g and where the process is carried out in steps comprising:

• I:
• reacting in the presence of (a) <5 wt % of 1-methyl-2-pyrrolidinone by weight of polyurethane and (b) at least one diluent, where the diluent comprises between 5 and 40% by weight of both the isocyanate-terminated prepolymer and the diluent together;
• 36 to 60 wt % of a mixture of toluene diisocyanate and methylene bis(phenyl isocyanate), wherein the mixture comprises 90 to 30 wt % of the methylene bis(phenyl isocyanate);
• (ii) 0 to 30 wt % of at least one aliphatic polyisocyanate;
• (iii) 0 to 15 wt % of at least one isocyanate-reactive polyol bearing ionic and/or potentially ionic water-dispersing groups with a weight average molecular weight <500 g/mol;
• (iv) 0 to 10 wt % of at least one isocyanate-reactive polyol bearing non-ionic water-dispersing groups;
• (v) 0 to 15 wt % of at least one isocyanate-reactive polyol with a weight average molecular weight <500 g/mol not comprised by (iii) or (iv);
• (vi) 20 to 58 wt % of at least one isocyanate-reactive polyol not comprised by (iii), (iv) or (v);
• where (i)+(ii)+(iii)+(iv)+(v)+(vi) add up to 100 wt %;
• where the NCO/OH ratio is in the range of from 1.2:1 to 2.5:1 to form an isocyanate-terminated prepolymer;
• II:
• neutralising the isocyanate-terminated prepolymer with a neutralising agent;
• III:
• forming an aqueous dispersion of the isocyanate-terminated prepolymer in water;
• IV:
• reacting the isocyanate-terminated prepolymer with at least one active hydrogen chain-extending compound to form the polyurethane;
• where the active hydrogen/NCO ratio is in the range of from 0.4:1 to 1:3:1;
• V:
• removing the diluent.

A process for making an aqueous composition with a sediment content <5%, comprising a polyurethane vinyl hybrid dispersion and containing <0.5 wt % of 1-methyl-2-pyrrolidinone by weight of the composition, wherein the polyurethane has an acid value in the range of from 18 to 65 mgKOH/g and where the process is carried out in steps comprising:

• I:
• reacting in the presence of (a) <5 wt % of 1-methyl-2-pyrrolidinone by weight of polyurethane and (b) at least one diluent, where the diluent comprises between 5 and 40% by weight of both the isocyanate-terminated prepolymer and the diluent together;
• 36 to 60 wt % of a mixture of toluene diisocyanate and methylene bis(phenyl isocyanate), wherein the mixture comprises 90 to 30 wt % of the methylene bis(phenyl isocyanate);
• (ii) 0 to 30 wt % of at least one aliphatic polyisocyanate;
• (iii) 0 to 15 wt % of at least one isocyanate-reactive polyol bearing ionic and/or potentially ionic water-dispersing groups with a weight average molecular weight <500 g/mol;
• (iv) 0 to 10 wt % of at least one isocyanate-reactive polyol bearing non-ionic water-dispersing groups;
• (v) 0 to 15 wt % of at least one isocyanate-reactive polyol with a weight average molecular weight <500 g/mol not comprised by (iii) or (iv);
• (vi) 20 to 58 wt % of at least one isocyanate-reactive polyol not comprised by (iii), (iv) or (v);
• where (i)+(ii)+(iii)+(iv)+(v)+(vi) add up to 100 wt %;
• where the NCO/OH ratio is in the range of from 1.2:1 to 2.5:1 to form an isocyanate-terminated prepolymer;
• II:
• neutralising the isocyanate-terminated prepolymer with a neutralising agent;
• III:
• forming an aqueous dispersion of the isocyanate-terminated prepolymer in water;
• IV:
• reacting the isocyanate-terminated prepolymer with at least one active hydrogen chain-extending compound to form the polyurethane;
• where the active hydrogen/NCO ratio is in the range of from 0.4:1 to 1:3:1;
• V:
• removing the diluent;
• VI:
• optionally adding vinyl monomer;
• and
• VI:
• polymerising the vinyl monomer added in step VI.

An aqueous composition with a sediment content <5%, comprising a polyurethane dispersion and containing <5 wt % of 1-methyl-2-pyrrolidinone by weight of the polyurethane, wherein the polyurethane has an acid value in the range of from 18 to 65 mgKOH/g and is obtained by the reaction of:

• A) an isocyanate-terminated prepolymer formed from components comprising:
• 36 to 60 wt % of a mixture of toluene diisocyanate and methylene bis(phenyl isocyanate), wherein the mixture comprises 90 to 30 wt % of the methylene bis(phenyl isocyanate);
• (ii) 0 to 30 wt % of at least one aliphatic organic polyisocyanate;
• (iii) 0 to 15 wt % of at least one isocyanate-reactive polyol bearing ionic and/or potentially ionic water-dispersing groups with a weight average molecular weight <500 g/mol;
• (iv) 0 to 10 wt % of at least one isocyanate-reactive polyol bearing non-ionic water-dispersing groups;
• (v) 0 to 15 wt % of at least one isocyanate-reactive polyol with a weight average molecular weight <500 g/mol not comprised by (iii) or (iv);
• (vi) 20 to 58 wt % of at least one isocyanate-reactive polyol not comprised by (iii), (iv) or (v);
• where (i)+(ii)+(iii)+(iv)+(v)+(vi) add up to 100 wt %;
• where the NCO/OH ratio is in the range of from 1 .2:1 to 2.5:1;
• and
• B) at least one active-hydrogen chain extending compound;
• where the active-hydrogen/NCO ratio is in the range of from 0.4:1 to 1.3:1;
• in the presence of
• (a) <5 wt % of 1-methyl-2-pyrrolidinone by weight of polyurethane,
• (b) at least one diluent, where the diluent comprises between 5 and 40% by weight of both the isocyanate-terminated prepolymer and the diluent together,
• (c) water, and
• (d) 2 to 15 wt. % of organic co-solvent Q having an evaporation rate from 0.001 to 0.1 relative to butyl acetate with an evaporation rate of 1.0.