High-modulus, flexible urethane coating and method of preparation

Claim 1

A method of preparing a high-modulus, solid urethane coating, which method comprises spraying onto a substrate substantially equal-volume amounts of an A-side and a B-side admixture together, to provide for the reaction of said mixture in about 5 seconds or less, to produce a high-modulus, solid coating, the A-side mixture comprising 100 parts of a prepolymer prepared by reacting about 25 to 35 parts of a polyether triol, having a hydroxyl number of about 50 or less, with from 65 to 75 parts of a low functionality MDI having a functionality of about 2.4 or less, and the B side comprising a polyol composition of from about 5 to 40 parts of a diol and from 60 to 95 parts of a polyether triol having a hydroxyl number of about 50 or less, and a catalytic amount of a catalyst composition comprising from about 0.01 to 1 part of the polyol composition and composed of a tetravalent tin salt catalyst in combination with a heat-activatable polyamine catalyst.

Claim 2

A method of preparing a high-modulus, solid urethane coating, which method comprises spraying onto a substrate substantially equal-volume amounts of an A-side and a B-side admixture together, to provide for the reaction of said mixture in about 5 seconds or less, to produce a high-modulus, solid coating, the A-side mixture comprising 100 parts of a prepolymer prepared by reacting about 25 to 35 parts of a polyether triol, having a hydroxyl number of about 50 or less, with from 65 to 75 parts of a low functionality MDI having a functionality of about 2.4 or less, and the B side comprising a polyol composition of from about 5 to 40 parts of a diol and from 60 to 95 parts of a polyether triol having a hydroxyl number of about 50 or less, and a catalytic amount of a catalyst composition comprising from about 0.01 to 1 part of the polyol composition and composed of a tetravalent tin salt catalyst in combination with a heat-activatable polyamine catalyst.

Claim 13

A method of preparing a high-modulus, solid, urethane coating composition, which method comprises spraying onto a substrate and reacting together substantial equal volumes of an A- and a B-side mixture, the A-side mixture comprising 100 parts by weight of a prepolymer prepared by reacting an ethylene-oxide-capped polypropylene oxide triol with a low-functionality MDI, the MDI having an average functionality of about 2.0, to provide a prepolymer having about 20% to 22% free NCO, and the B-side mixture comprising from about 2 to 40 parts of a diethylene diol and 60 to 95 parts of an ethylene-oxide-capped polypropylene oxide triol having a hydroxyl number of about 50 or less, and a catalytic amount of a tetravalent tin salt catalyst in combination with a heat-activatable, formic-acid-blocked triethylene diamine, and an antifoaming amount of a degassing agent, the reaction to cream carried out in about 5 seconds or less.

Claim 14

A method of preparing a high-modulus, solid, urethane coating composition, which method comprises spraying onto a substrate and reacting together substantial equal volumes of an A- and a B-side mixture, the A-side mixture comprising 100 parts by weight of a prepolymer prepared by reacting an ethylene-oxide-capped polypropylene oxide triol with a low-functionality MDI, the MDI having an average functionality of about 2.0, to provide a prepolymer having about 20% to 22% free NCO, and the B-side mixture comprising from about 2 to 40 parts of a diethylene diol and 60 to 95 parts of an ethylene-oxide-capped polypropylene oxide triol having a hydroxyl number of about 50 or less, and a catalytic amount of a tetravalent tin salt catalyst in combination with a heat-activatable, formic-acid-blocked triethylene diamine, and an antifoaming amount of a degassing agent, the reaction to cream carried out in about 5 seconds or less.