Structural urethane adhesives comprising amide polyols

1. A urethane adhesive composition comprising an amide polyol consisting of the reaction product of a reactant selected from the group consisting of lactic acid, lactic acid esters, glycolic acid, glycolic acid esters, and combinations thereof with one or more amines.

2. The urethane adhesive composition of claim 1 wherein the lactic acid ester is selected from the group consisting of lactide (3,6-dimethyl-1,4-dioxane-2,5-dione), methyl lactate, ethyl lactate, propyl lactate, iso-propyl lactate, butyl lactate, tert-butyl lactate, iso-butyl lactate, pentyl lactate and combinations thereof.

3. The urethane adhesive composition of claim 1 wherein the glycolic acid ester is selected from the group consisting of glycolide (1,4-dioxane-2,5-dione), methyl glycolate, ethyl glycolate, propyl glycolate, iso-propyl glycolate, butyl glycolate, tert-butyl glycolate, iso-butyl glycolate, pentyl glycolate and combinations thereof.

4. The urethane adhesive composition of claim 1 wherein the amine is selected from the group consisting of a primary amine, a secondary amine and combinations thereof.

5. The urethane adhesive composition of claim 1 wherein the amine is an aliphatic amine.

6. The urethane adhesive composition of claim 1 wherein the amine is selected from the group consisting of N,N′-bis(3-aminopropyl)methylamine, N,N′-dimethylethylene diamine, neopentanediamine, 4,4′-diaminodiphenyl methane, 2-methylpentamethylenediamine and polyetheramine.

7. The urethane adhesive composition of claim 6 wherein the polyetheramine is selected from the group consisting of

a) an amine having the structure

wherein n is about 2.5 to about 68,

b) an amine having the structure

wherein m is about 2 or about 3 and

c) an amine having the structure

wherein R is H or C 2 H 5 , k is 0 or 1, and the total of x, y and z is about 5 to about 85.

8. The urethane adhesive composition of claim 1 comprising a prepolymer and a curative wherein the curative comprises the amide polyol.

9. A method of adhering at least one ceramic substrate to another ceramic substrate comprising the steps of applying the urethane adhesive composition of claim 1 to one or more of the ceramic substrates and contacting the ceramic substrate with the adhesive composition to another ceramic substrate.

10. A method of manufacturing a tile installation comprising the steps a) placing an underlayment over an existing surface, b) placing at least two tiles on the underlayment separated by a gap between the tiles and c) applying the urethane adhesive composition of claim 1 in the gap between the tiles.