Coated particles and methods for their manufacture and use

1. A coated particle comprising:

a substrate particle having a particle size of no more than 3 mesh; and

a coating disposed over at least a portion of the particle, wherein the coating comprises a crystalline or semicrystalline polyester/polyurethane that is a reaction product of reactants comprising:

(a) a di- or poly-functional polymeric polyol with a number average molecular weight of from 400 to 5,000 g/mole and comprising a polyester polyol;

(b) a di- or poly-functional isocyanate component; and

(c) an alkoxysilane comprising either an isocyanate group or an isocyanate-reactive group, and wherein the reaction product has a decrystallization temperature of 40° C. to 60° C.

2. The coated particle of claim 1 , wherein the substrate particle comprises sand.

3. The coated particle of claim 1 , wherein the coated particle is a solid free-flowing particle at a temperature that is below the decrystallization temperature of the crystalline or semicrystalline polyester/polyurethane.

4. The coating particle of claim 1 , wherein the crystalline or semicrystalline polyester/polyurethane has a decrystallization temperature of 45° C. to 52° C.

5. The coated particle of claim 1 , wherein the polyester/polyurethane has a weight-average molecular weight of 20,000 to 250,000 g/mole.

6. The coated particle of claim 1 , wherein the di- or poly-functional polymeric polyol comprises a reaction product of reactants comprising:

(a) a dicarboxylic acid comprising succinic acid, adipic acid, dodecandoic acid, one or more derivatives thereof, or a mixture thereof, employed in an amount of at least 80 mole %, based on the total amount of all carboxylic acid used to make the polymeric polyol; and

(b) a polyol comprising monoethylene glycol, 1,3-propanediol, butanediol-1,4, pentanediol-1,5, hexanediol-1,6, neopentyl glycol, or a mixture thereof, employed in an amount of at least 80 mole %, based on the total amount of all polyol used to make the polymeric polyol.

7. The coated particle of claim 1 , wherein the di- or poly-functional polymeric polyol comprises:

(i) at least 50 percent by weight, based on the total weight of the di- or poly-functional polyester-polyol in the composition, of a polyester polyol comprising a reaction product of reactants comprising:

(A) at least 80 mole % adipic acid, based on the total amount of all carboxylic acids used to make the polyester polyol, and

(B) at least 80 mole % butanediol-1,4, based on the total amount of all polyols used to make the polyester polyol; and

(ii) up to 50 percent by weight, based on the total weight of the di- or poly-functional polyester-polyol in the composition, of a polyester polyol comprising a reaction product of reactants comprising:

(A) at least 80 mole % adipic acid, based on the total amount of all carboxylic acids used to make the polyester polyol,

(B) at least 40 mole % hexanediol-1,6, based on the total amount of all polyols used to make the polyester polyol; and

(C) up to 60 mole % 2,2-dimethyl-1,3-propanediol, based on the total amount of all polyols used to make the polyester polyol.

8. The coated particle of claim 1 , wherein the reactants further comprise at least one of:

(d) a di- or poly-functional polyol with a molecular weight of from 62 to 399 g/mole;

(e) a component comprising sulfonate and/or carboxylate groups and which furthermore has at least one isocyanate-reactive group;

(f) an aminic chain extender; and

(g) an isocyanate-reactive compound comprising an aliphatic, cycloaliphatic or aromatic monoalcohols having 2 to 22 carbon atoms.

9. The coated particle of claim 8 , wherein the reactants comprise (e) and (f).

10. The coated particle of claim 1 , wherein the coated particle has a particle size of 10 to 100 mesh.