Two-component adhesive composition and cured product

Abstract

Provided are: a two-pack type adhesive composition which gives cured objects having excellent tensile properties and a small temperature dependence of viscoelastic properties (storage modulus) and which can stably exhibit adhesiveness in a wide temperature range; and a cured object. The two-pack type adhesive composition comprises a main ingredient comprising an isocyanate-terminated urethane prepolymer and a hardener comprising a polyoxyalkylene polymer having four or more functional groups, wherein the polyoxyalkylene polymer has a number-average molecular weight of 6,000 or higher.

Claims

1. A two-component adhesive composition comprising a main component containing an isocyanate-terminated urethane prepolymer and a curing agent containing a polyoxyalkylene polymer having four or more functional groups, wherein the number-average molecular weight of the polyoxyalkylene polymer is 6000 or more, and the ratio of units based on propylene oxide to the total amount of oxyalkylene groups in the polyoxyalkylene polymer is 60% by mass or more.

2. The polyoxyalkylene polymer has units based on ethylene oxide, as described in claim 1, for the two-component adhesive composition.

3. The two-component adhesive composition according to claim 2, wherein the polyoxyalkylene polymer has a proportion of ethylene oxide-based units in the polyoxyalkylene polymer of 5% by mass or more and 40% by mass or less.

4. The two-component adhesive composition according to claim 1, wherein the intercrosslink molecular weight obtained by dividing the number-average molecular weight of the polyoxyalkylene polymer by the number of functional groups per molecule of the polyoxyalkylene polymer is 1400 or more and 9000 or less.

5. The two-component adhesive composition according to claim 1, wherein the functional group is a hydroxyl group.

6. The two-component adhesive composition according to claim 5, wherein the isocyanate index, which represents 100 times the molar ratio (isocyanate group / hydroxyl group) of isocyanate groups in the isocyanate-terminated urethane prepolymer to the hydroxyl groups in the polyoxyalkylene polymer, is 80 or more and 150 or less.

7. The two-component adhesive composition according to claim 1, wherein the total proportion of the main component and the curing agent in the two-component adhesive composition is 50% by mass or more.

8. A cured product obtained by curing a two-component adhesive composition according to any one of claims 1 to 7.

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