Pressure-sensitive adhesive composition produced from a base block copolymer, a resinous tackifier, a naphthenic or parffinic mineral oil, and an aromatic synthetic oil

An adhesive composition of a thermoplastic elastomer type which comprises:

• (I) 100 weight parts of a base polymer of a block copolymer or its hydrogenated derivative represented by the formula
• A--B--A).sub.n
• where A is a block polymer of a monovinyl substituted aromatic hydrocarbon, B is an elastomeric block polymer of a conjugated diene, and n is an integer of 1-5;
• (II) 50-200 weight parts of a resinous tackifier;
• (III) 5-50 weight parts of a softener which is a naphthenic or paraffinic mineral oil;
• and
• (IV) 1-40 weight parts of at least one of the following synthetic oils:
• (a) a synthetic oil having a molecular weight of 173-263 and represented by the formula
• Ar.sub.1 --R--Ar.sub.2
• where Ar.sub.1 and Ar.sub.2 are each benzene or alkyl benzene rings and may be the same or different, and R is an alkylene group of 2-3 carbon atoms;
• (b) a synthetic oil having a molecular weight of 300-398 and represented by the formula
• Ar.sub.1 --R.sub.1 --Ar.sub.2 --R.sub.2 --Ar.sub.3
• where Ar.sub.1, Ar.sub.2 and Ar.sub.3 are each benzene or alkyl benzene rings and may be the same or different, R.sub.1 and R.sub.2 are each alkylene groups of 2-3 carbon atoms and may be the same or different;
• and
• (c) a synthetic oil having a molecular weight of 300-398 and represented by the formula ##STR3## where Ar.sub.1, Ar.sub.2 and Ar.sub.3 are each benzene or alkyl benzene rings and may be the same or different, and R is a straight-chain or branched-chain hydrocarbon group of 4-6 carbon atoms,
• whereby, the composition has an adhesive force of longer than 180 minutes as determined on corrugated fiberboard at a temperature of 25.degree. C. and at a load of 2,000 g.