COATED AND CURED PROPPANTS
Solid proppants are coated with a phenol-urethane coating in one or more layers by a method comprising coating a proppant solid and then curing the coated proppant under conditions sufficient to substantially cure said proppant, wherein said coating comprises a substantially homogeneous mixture of (i) an isocyanate component having at least 2 isocyanate groups, (ii) an amine reactant, and optionally (iii) an amine that is a latent curing agent for said isocyanate.
1 - 24 . (canceled)
25 . A coated proppant solid comprising a solid proppant core particle substantially covered with a isocyanate-polyol condensation reaction product,
wherein the isocyanate is in excess relative to the polyol and the polyol is a hydroxy-functional polyether.
26 . The coated proppant solid of claim 25 , wherein the proppant solid exhibits a low rate of flow back.
27 . The coated proppant solid of claim 25 , wherein the proppant solid has sufficiently high crush resistance to maintain conductivity in a subterranean fracture.
28 . The coated proppant of claim 25 , wherein the coating further comprises an adhesion agent.
29 . The coated proppant of claim 25 , wherein the coating further comprises a silane.
30 . The coated proppant of claim 25 , wherein the coating further comprises a surface-active agent.
31 . The coated proppant of claim 25 , wherein the coating further comprises a nanofiller.
32 . The coated proppant of claim 25 , wherein the solid proppant core particle is a ceramic core particle.
33 . The coated proppant of claim 25 , wherein the solid proppant core particle is a sand particle.
34 . The coated proppant of claim 25 , wherein the coating further comprises a pigment, dye, or tint.
35 . The coated proppant of claim 25 , wherein the coating further comprises mica.
36 . A process for making the coated proppant solid of claim 25 , the process comprising mixing a solid proppant core particle with an isocyanate and a polyol under conditions to coat the proppant solid with a isocyanate-polyol condensation reaction product,
wherein the polyol is a hydroxy-functional polyether and the isocyanate is in excess relative to the polyol.
37 . The process of claim 36 , wherein the isocyanate is present in an amount of 105-300 wt % of isocyanate base value relative to the weight of the polyol.
38 . The process of claim 36 , further comprising mixing the solid proppant core particle with an adhesion agent.
39 . The process of claim 36 , further comprising mixing the solid proppant core particle with a silane.
40 . The process of claim 36 , further comprising mixing the solid proppant core particle with a surface-active agent.
41 . The process of claim 36 , further comprising mixing the solid proppant core particle with a nanofiller.
42 . The process of claim 36 , wherein the solid proppant core particle is a sand particle or a ceramic particle.
43 . The process of claim 36 , further comprising mixing the solid proppant core particle with a pigment, dye, or tint.