Polyolefin-based adhesive composition
Provided is an adhesive composition comprising a modified polyolefin and an epoxy resin, the composition having excellent pot life, and excellent adhesion to both a metal substrate and a polyolefin resin substrate. The adhesive composition comprises a modified polyolefin (A), a glycidyl amine-type epoxy resin (B1), a glycidyl ether-type epoxy resin (B2), and an organic solvent (C); wherein the modified polyolefin (A) is (A1) or (A2) below: (A1): a crystalline acid-modified polyolefin having an acid value of 5 to 50 mg KOH/g-resin; or (A2): an acid-modified chlorinated polyolefin having an acid value of 5 to 50 mg KOH/g-resin and a chlorine content of 5 to 40 mass %.
1. An adhesive composition comprising:
a modified polyolefin (A),
a glycidyl amine epoxy resin (B1),
a glycidyl ether epoxy resin (B2), and
an organic solvent (C);
wherein the modified polyolefin (A) is (A1) or (A2) below:
(A1): a crystalline acid-modified polyolefin having an acid value of 5 to 50 mg KOH/g-resin; or
(A2): an acid-modified chlorinated polyolefin having an acid value of 5 to 50 mg KOH/g-resin and a chlorine content of 5 to 40 mass %.
2. The adhesive composition according to claim 1 , wherein the glycidyl amine epoxy resin (B1) is an epoxy resin having two or more glycidyl groups per molecule.
3. The adhesive composition according to claim 1 , wherein the glycidyl amine epoxy resin (B1) is a compound represented by Formula (1):
wherein in Formula (1), R is substituted or unsubstituted aryl group, X1 and X2 are independently substituted or unsubstituted C 1 -C 5 alkylene group, m is 1 or 2, and n is 1 or 2.
4. The adhesive composition according to claim 1 , wherein the glycidyl ether epoxy resin (B2) is an epoxy resin having two or more glycidyl groups per molecule and being free from nitrogen atom.
5. The adhesive composition according to claim 1 , wherein the composition comprises 0.01 to 20 parts by mass of glycidyl amine epoxy resin (B1), 1 to 20 parts by mass of glycidyl ether epoxy resin (B2), and 80 to 1000 parts by mass of organic solvent (C), based on 100 parts by mass of modified polyolefin (A).
6. The adhesive composition according to claim 1 , wherein the organic solvent (C) is a mixture of a solvent (C1) and a solvent (C2);
the solvent (C1) is one or more solvents selected from the group consisting of aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons, and halogenated hydrocarbons;
the solvent (C2) is one or more solvents selected from the group consisting of alcohol-based solvents, ketone-based solvents, ester-based solvents, and glycol ether-based solvents; and
the mass ratio of the solvent (C1) to the solvent (C2) is 50 to 97/50 to 3.
7. The adhesive composition according to claim 1 , which is used for bonding between a polyolefin resin substrate and a metal substrate.
8. A laminate of a polyolefin resin substrate and a metal substrate bonded with the adhesive composition according to claim 1 .