AQUEOUS POLYURETHANUREA COMPOSITIONS INCLUDING DISPERSIONS AND FILMS
Included are polyurethaneurea compositions include polyurethaneurea aqueous dispersions. The dispersions may be prepared with solvent or in the absence of any added solvent. Films and other shaped articles may be prepared from the dispersions by a casting a drying method and optionally included with a substrate including paper, fabric or garments. The films exhibit a reduced discoloring or yellowing upon exposure to atmosphere, heat, and UV.
1 . A composition comprising;
(a) a polyurethaneurea aqueous dispersion comprising a polymer which is the reaction product of:
(1) at least one polyol selected from polyethers, polyesters, polycarbonates, and combinations thereof, wherein the polyol has a number average molecular weight of 600 to 4000;
(2) a polyisocyanate comprising at least one aromatic diisocyanate;
(3) optionally a neutralizing agent and a diol compound comprising: (i) hydroxy groups capable of reacting with polyisocyanate, and (ii) at least one carboxylic acid group capable of forming a salt upon neutralization, wherein said at least one carboxylic acid group is incapable of reacting with the polyisocyanate;
(4) a chain extender selected from the group consisting of diamine chain extenders, water, and combinations thereof; and
(5) optionally including a blocking agent for isocyanate;
(6) at least one surface active agent; and
(b) an anti-yellowing compound selected from the group consisting of a monoisocyanate, an aliphatic diisocyanate, and combinations thereof.
2 . The composition of claim 1 , wherein said a blocking agent for isocyanate groups is included and comprises at least one monofunctional alcohol.
3 . The composition of claim 1 , wherein said anti-yellowing compound is selected from the group consisting of cyclohexyl isocyanate, phenyl isocyanate, ethyl isocyanate, ethyl isocyanatoacetate and combinations thereof.
4 . The composition of claim 1 , wherein said anti-yellowing compound is present in an amount of about 1% to about 15% by weight of the dispersion.
5 . The composition of claim 1 , wherein said anti-yellowing compound is present in an amount of about 3% to about 10% by weight of the dispersion.
6 . A film cast and dried from a composition comprising
(a) a polyurethaneurea aqueous dispersion comprising a polymer which is the reaction product of:
(1) at least one polyol selected from polyethers, polyesters, polycarbonates, and combinations thereof, wherein the polyol has a number average molecular weight of 600 to 4000;
(2) a polyisocyanate comprising at least one aromatic diisocyanate;
(3) optionally a neutralizing agent and a diol compound comprising: (i) hydroxy groups capable of reacting with polyisocyanate, and (ii) at least one carboxylic acid group capable of forming a salt upon neutralization, wherein said at least one carboxylic acid group is incapable of reacting with the polyisocyanate;
(4) a chain extender selected from the group consisting of diamine chain extenders, water, and combinations thereof; and
(5) optionally including a blocking agent for isocyanate;
(6) at least one surface active agent; and
(b) an anti-yellowing compound selected from the group consisting of a monoisocyanate, an aliphatic diisocyanate, and combinations thereof.
7 . The composition of claim 6 , wherein said a blocking agent for isocyanate groups is included and comprises at least one monofunctional alcohol.
8 . The composition of claim 6 , wherein said compound is selected from the group consisting of cyclohexyl isocyanate, phenyl isocyanate, ethyl isocyanate, ethyl isocyanatoacetate and combinations thereof.
9 . The composition of claim 6 , wherein said monoisocyanate is present in an amount of about 1% to about 15% by weight of the dispersion.
10 . The composition of claim 6 , wherein said monoisocyanate is present in an amount of about 3% to about 10% by weight of the dispersion.
11 . A method for reducing yellowing in a film comprising:
(a) preparing a polyurethaneurea aqueous dispersion comprising a polymer which is the reaction product of:
(1) at least one polyol selected from polyethers, polyesters, polycarbonates, and combinations thereof, wherein the polyol has a number average molecular weight of 600 to 4000;
(2) a polyisocyanate comprising at least one aromatic diisocyanate;
(3) optionally a neutralizing agent and a diol compound comprising: (i) hydroxy groups capable of reacting with polyisocyanate, and (ii) at least one carboxylic acid group capable of forming a salt upon neutralization, wherein said at least one carboxylic acid group is incapable of reacting with the polyisocyanate;
(4) a chain extender selected from the group consisting of diamine chain extenders, water, and combinations thereof; and
(5) optionally including a blocking agent for isocyanate;
(6) at least one surface active agent;
(b) adding to said dispersion an anti-yellowing compound selected from the group consisting of a monoisocyanate, an aliphatic diisocyanate, and combinations thereof; and
(c) preparing a shaped article from said dispersion.
12 . The method of claim 11 , wherein said a blocking agent for isocyanate groups is included and comprises at least one monofunctional alcohol.
13 . The method of claim 11 , wherein said anti-yellowing compound is selected from the group consisting of cyclohexyl isocyanate, phenyl isocyanate, ethyl isocyanate, ethyl isocyanatoacetate and combinations thereof.
14 . The method of claim 11 , wherein said anti-yellowing compound is present in an amount of about 1% to about 15% by weight of the dispersion.
15 . The method of claim 11 , wherein said anti-yellowing compound is present in an amount of about 3% to about 10% by weight of the dispersion.