Two-pack curable urethane adhesive composition

1. A two-part curable urethane adhesive composition comprising:

a base agent containing a urethane prepolymer, and a curing agent containing a compound having two or more active hydrogen groups in each molecule;

the curing agent containing at least one type of terpene compound selected from the group consisting of monoterpenes, hydrogenated monoterpenes, modified monoterpenes formed by modifying the monoterpenes or the hydrogenated monoterpenes with hydroxy groups, and oligomers having from 2 to 6 repeating units derived from the monoterpenes or the modified monoterpenes.

2. The two-part curable urethane adhesive composition according to claim 1 , wherein

the monoterpene is a compound represented by Formula (1), a compound represented by Formula (2), or a compound represented by Formula (3);

the hydrogenated monoterpene is a compound represented by Formula (4);

the modified monoterpene is a compound represented by Formula (5), a compound represented by Formula (6), or a compound represented by Formula (7); and

the oligomer is a compound represented by Formula (8), a compound represented by Formula (9), or a compound represented by Formula (10):

where, in Formulas (8) to (10), m represents a number from 2 to 6, n represents a number from 1 to 3, and m×n is a number from 2 to 6; and in Formula (9), R represents a hydrogen atom or an alkyl group having from 1 to 12 carbons.

3. The two-part curable urethane adhesive composition according to claim 1 , wherein a content of the terpene compound is from 1 to 30 mass % relative to the total mass of the curing agent.

4. The two-part curable urethane adhesive composition according to claim 1 , wherein the curing agent contains a polybutadiene diol as the compound having two or more active hydrogen groups in each molecule.

5. The two-part curable urethane adhesive composition according to claim 1 , wherein the curing agent contains a rosin diol as the compound having two or more active hydrogen groups in each molecule.

6. The two-part curable urethane adhesive composition according to claim 1 , wherein the base agent further contains an isocyanate silane compound.

7. The two-part curable urethane adhesive composition according to claim 1 , wherein the curing agent contains a polyol compound as the compound having two or more active hydrogen groups in each molecule; and

the two-part curable urethane adhesive composition is used for adhesion to a resin material using no primer.

8. The two-part curable urethane adhesive composition according to claim 1 , wherein the terpene compound is at least one type selected from the group consisting of monoterpenes, hydrogenated monoterpenes, and modified monoterpenes formed by modifying the monoterpenes or the hydrogenated monoterpenes with hydroxy groups.

9. The two-part curable urethane adhesive composition according to claim 2 , wherein a content of the terpene compound is from 1 to 30 mass % relative to the total mass of the curing agent.

10. The two-part curable urethane adhesive composition according to claim 2 , wherein the curing agent contains a polybutadiene diol as the compound having two or more active hydrogen groups in each molecule.

11. The two-part curable urethane adhesive composition according to claim 3 , wherein the curing agent contains a polybutadiene diol as the compound having two or more active hydrogen groups in each molecule.

12. The two-part curable urethane adhesive composition according to claim 9 , wherein the curing agent contains a polybutadiene diol as the compound having two or more active hydrogen groups in each molecule.

13. The two-part curable urethane adhesive composition according to claim 2 , wherein the curing agent contains a rosin diol as the compound having two or more active hydrogen groups in each molecule.

14. The two-part curable urethane adhesive composition according to claim 3 , wherein the curing agent contains a rosin diol as the compound having two or more active hydrogen groups in each molecule.

15. The two-part curable urethane adhesive composition according to claim 4 , wherein the curing agent contains a rosin diol as the compound having two or more active hydrogen groups in each molecule.

16. The two-part curable urethane adhesive composition according to claim 9 , wherein the curing agent contains a rosin diol as the compound having two or more active hydrogen groups in each molecule.

17. The two-part curable urethane adhesive composition according to claim 10 , wherein the curing agent contains a rosin diol as the compound having two or more active hydrogen groups in each molecule.

18. The two-part curable urethane adhesive composition according to claim 11 , wherein the curing agent contains a rosin diol as the compound having two or more active hydrogen groups in each molecule.

19. The two-part curable urethane adhesive composition according to claim 12 , wherein the curing agent contains a rosin diol as the compound having two or more active hydrogen groups in each molecule.

20. The two-part curable urethane adhesive composition according to claim 2 , wherein the base agent further contains an isocyanate silane compound.