Urethane prepolymer composition and a polyurethane coating composition system

Claim 2

A urethane prepolymer composition comprising: (a) a terminal isocyanate group-containing urethane prepolymer obtained by reacting a polytetramethylene glycol having a number average molecular weight of from 700 to 1500 with at least one diisocyanate selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate at an equivalent ratio of the isocyanate groups of said diisocyanate to the hydroxyl groups of said glycol of at least 5/1, and (b) a terminal isocyanate group-containing urethane prepolymer obtained by reacting at least one polycaprolactone having at least two terminal hydroxyl groups, said polycaprolactone being selected from the group consisting of a polycaprolactone diol and a polycaprolactone polyol each having a number average molecular weight of from 500 to 1500, with at least one diisocyanate selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate at an equivalent ratio of the isocyanate groups of said diisocyanate to the hydroxyl groups of said polycaprolactone of at least 5/1, the weight ratio of (a) to (b) being in the range of from 80/20 to 20/80.

Claim 3

The urethane prepolymer composition according to claim 1, wherein said polycaprolactone is a poly-ε-caprolactone.

Claim 4

The urethane prepolymer composition according to claim 1, wherein the aliphatic and alicyclic diisocyanates of (a) and (b), respectively, have 4 to 30 and 8 to 30 carbon atoms.

Claim 5

The urethane prepolymer composition according to claim 3, wherein the diisocyanates of (a) and (b) are each selected from the group consisting of 1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4-trimethyl-1,6-hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane and 4,4'-dicyclohexylmethane diisocyanate.

Claim 6

The urethane prepolymer composition according to claim 4, wherein the diisocyanates of (a) and (b) are each 1,6-hexamethylene diisocyanate.

Claim 7

The urethane prepolymer composition according to claim 1, wherein the equivalent ratio of the isocyanate groups of said diisocyanate to the hydroxyl groups of said glycol of (a) and the equivalent ratio of the isocyanate groups of said diisocyanate to the hydroxyl groups of said polycaprolactone of (b) are each at least 8/1.

Claim 8

A polyurethane coating composition system comprising components (A) and (B), in which said components are separately provided and are adapted to being mixed when used, wherein said components are defined as follows: (A) a urethane prepolymer composition comprising: (a) a terminal isocyanate group-containing urethane prepolymer obtained by reacting a polytetramethylene glycol having a number average molecular weight of from 700 to 1500 with at least one diisocyanate selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate at an equivalent ratio of the isocyanate groups of said diisocyanate to the hydroxyl groups of said glycol of at least 5/1, and (b) a terminal isocyanate group-containing urethane prepolymer obtained by reacting at least one polycaprolactone having at least two terminal hydroxyl groups, said polycaprolactone being selected from the group consisting of a polycaprolactone diol and a polycaprolactone polyol each having a number average molecular weight of from 500 to 1500, with at least one diisocyanate selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate at an equivalent ratio of the isocyanate groups of said diisocyanate to the hydroxyl groups of said polycaprolactone of at least 5/1, the weight ratio of (a) to (b) being in the range of from 80/20 to 20/80; and (B) at least one compound having at least two hydroxyl groups, said compound being selected from the group consisting of a diol compound and a polyol compound, wherein the equivalent ratio of the total number of the terminal isocyanate groups of (a) and (b) to the hydroxyl groups of component (B) is in the range of from 0.5/1 to 2.0/1.

Claim 9

A polyurethane coating composition system comprising components (A) and (B), in which said components are separately provided and are adapted to being mixed when used, wherein said components are defined as follows: (A) a urethane prepolymer composition comprising: (a) a terminal isocyanate group-containing urethane prepolymer obtained by reacting a polytetramethylene glycol having a number average molecular weight of from 700 to 1500 with at least one diisocyanate selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate at an equivalent ratio of the isocyanate groups of said diisocyanate to the hydroxyl groups of said glycol of at least 5/1, and (b) a terminal isocyanate group-containing urethane prepolymer obtained by reacting at least one polycaprolactone having at least two terminal hydroxyl groups, said polycaprolactone being selected from the group consisting of a polycaprolactone diol and a polycaprolactone polyol each having a number average molecular weight of from 500 to 1500, with at least one diisocyanate selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate at an equivalent ratio of the isocyanate groups of said diisocyanate to the hydroxyl groups of said polycaprolactone of at least 5/1, the weight ratio of (a) to (b) being in the range of from 80/20 to 20/80; and (B) at least one compound having at least two hydroxyl groups, said compound being selected from the group consisting of a diol compound and a polyol compound, wherein the equivalent ratio of the total number of the terminal isocyanate groups of (a) and (b) to the hydroxyl groups of component (B) is in the range of from 0.5/1 to 2.0/1.

Claim 10

The polyurethane coating composition system according to claim 7, wherein the compound having at least two hydroxyl groups of component (B) has a number average molecular weight of from 300 to 30,000.

Claim 11

The polyurethane coating composition system according to claim 8, wherein the compound having at least two hydroxyl groups of component (B) is an acrylic polyol.

Claim 12

The polyurethane coating composition system according to claim 9, wherein said acrylic polyol has a glass transition temperature of from 30° to 100° C. and a hydroxyl value of from 10 to 150 mgKOH/g of the polyol.

Claim 13

The polyurethane coating composition system according to claim 7, wherein the aliphatic and alicyclic diisocyanates of (a) and (b), respectively, have 4 to 30 and 8 to 30 carbon atoms.

Claim 14

The polyurethane coating composition system according to claim 11, wherein the diisocyanates of (a) and (b) are each selected from the group consisting of 1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4-trimethyl-1,6-hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane and 4,4'-dicyclohexylmethane diisocyanate.

Claim 15

The polyurethane coating composition system according to claim 12, wherein the diisocyanates of (a) and (b) are each 1,6-hexamethylene diisocyanate.

Claim 16

The polyurethane coating composition system according to claim 7, comprising at least one stabilizer selected from the group consisting of a benzotriazole compound, a hindered phenol compound and a hindered amine compound.