Process for preparing polycarbamate and reaction product thereof
A first process to produce polycarbamate comprising providing urea in liquid form; and adding the liquid urea to a polyol is provided. A second process for producing polycarbamate comprising adding solid urea to a polyol in liquid form to form a reaction mixture is provided. Also provided is a reaction product produced by the first process or second process.
1. A process to produce polycarbamate comprising:
providing urea in liquid form, wherein said urea is dissolved in water; and
adding the liquid urea to a polyol;
wherein the polyol is dissolved in a solvent;
wherein the polyol is selected from the group consisting of acrylic, styrene-acrylic, styrene-butadiene, saturated polyester, polyalkylene polyols, urethane, alkyd, polyether and polycarbonate; and
wherein said process produces a polycarbamate characterized by the following:
(i) comprising less than 0.2 wt % cyanuric acid;
(ii) comprising less than 0.6 wt % biuret;
(iii) comprising less than 2 wt % polyallophanate; and
(iv) exhibiting a Gardner color of less than or equal to 2.
2. The process according to claim 1 , wherein the adding the liquid urea to the polyol is conducted in a semi-batch manner and wherein the liquid urea is added to the polyol at a constant, pulsed, or variable rate of addition.
3. The process according to claim 1 , wherein the adding the liquid urea to the polyol is conducted in the presence of a catalyst.
4. The process according to claim 1 wherein the water and solvent form a heterogeneous azeotrope allowing removal of the water and the solvent being returned to the reactor.
5. The process according to claim 4 wherein the removal of the water is by decantation.