Dispersants made from isocyanates and amines
The present disclosure generally relates to a dispersant obtained from the reaction of a liquid isocyanate compound and a polyoxyalkylene amine and its use in dispersing various particulate solids in an aqueous or organic medium.
1 . A dispersant substantially free of biuret groups obtained from the reaction of: (i) a liquid isocyanate compound substantially free of an isocyanate prepolymer, wherein the liquid isocyanate compound is a polyisocyanate compound comprising a functional group selected from the group consisting of, an iminooxadiazine, a uretdione, an allophant and combinations thereof; and (ii) a polyoxyalkylene monoamine wherein the ratio of the number of amino groups from the polyoxyalkylene monoamine to the number of isocyanate groups from the liquid isocyanate compound is within the range of 0.95 to 1.2.
2 . The dispersant of claim 1 , wherein the functional group is a uretdione group.
3 . The dispersant of claim 1 , wherein the polyoxyalkylene monoamine is a compound having a formula
where R 1 is hydrogen, a C 1 to C 20 alkyl group or a C 6 aryl group optionally substituted with one or more C 1 to C 10 alkyl groups; w, x, and y are each independently an integer from zero to about 100, subject to the proviso that w+x+y is greater than two; d is 0 or 1; and, R b is a C 1 to C 10 alkyl group.
4 . The dispersant of claim 1 , wherein the polyoxyalkylene monoamine has a formula
where R is methyl and a and b are integers such that the mole ratio of PO/EO in the monoamine ranges from about 9/1 to about 1/11.
5 . A composition comprising the dispersant of claim 1 , a particulate solid and one of an organic medium or and aqueous medium.
6 . The composition of claim 5 , wherein the organic medium is present and is a polar organic medium.
7 . The composition of claim 5 , wherein the organic medium is present and is a non-polar organic medium.
8 . The composition of claim 5 , wherein the particulate solid is a pigment.
9 . The composition of claim 5 , wherein the composition further comprises a binder.
10 . The composition according to claim 5 , wherein a coating is disposed on the particulate solid.
11 . The composition according to claim 5 , wherein the composition comprises the aqueous medium.
12 . The composition of claim 11 , wherein the particulate solid is a pigment.
13 . A method of forming a dispersant according to claim 1 comprising contacting the liquid isocyanate compound and the polyoxyalkylene momoamine and allowing the liquid isocyanate compound and the polyoxyalkylene monoamine to react and form the dispersant.
14 . The method of claim 13 , wherein the reaction is conducted at ambient temperature and/or in the absence of a catalyst.
15 . The method according to claim 13 , further comprising dispersing a particulate solid in an aqueous or organic medium comprising an effective amount of the dispersant and contacting the particulate solid with the dispersant.