Acrylic pressure-sensitive adhesive composition, acrylic pressure-sensitive adhesive layer, and acrylic pressure-sensitive adhesive tape
An acrylic pressure-sensitive adhesive composition contains 100 parts by mass of an acrylic polymer (A), 1 to 70 parts by mass of a (meth)acrylic polymer (B) having a weight average molecular weight (Mw) of 1000≦Mw<30000, and 1 to 50 parts by mass of a hydrogenated tackifying resin (C). The (meth)acrylic polymer (B) is a polymer having a weight average molecular weight smaller than that of the acrylic polymer (A) as a pressure-sensitive adhesive composition, and functions as a tackifying resin along with the hydrogenated tackifying resin (C).
1. An acrylic pressure-sensitive adhesive composition, comprising:
100 parts by mass of an acrylic polymer (A);
1 to 70 parts by mass of a (meth)acrylic polymer (B) having a weight average molecular weight (Mw) of 1000≦Mw<30000; and
1 to 50 parts by mass of a hydrogenated tackifying resin (C),
wherein the glass transition temperature (Tg) of the (meth)acrylic polymer (B) is 0° C.≦Tg≦300° C, and
wherein the ratio of the (meth)acrylic polymer (B)/the hydrogenated tackifying resin (C) is from 1/1.7 to 1/0.12.
2. The acrylic pressure-sensitive adhesive composition according to claim 1 , wherein the (meth)acrylic polymer (B) contains, as a monomer unit, a (meth)acrylic monomer having an alicyclic structure in its side chain.
3. The acrylic pressure-sensitive adhesive composition according to claim 2 , wherein an alicyclic hydrocarbon group in the (meth)acrylic monomer having an alicyclic structure has a bridged ring structure.
4. The acrylic pressure-sensitive adhesive composition according to claim 1 , wherein the hydrogenated tackifying resin (C) is a petroleum resin or a terpene resin.
5. The acrylic pressure-sensitive adhesive composition according to claim 1 , wherein the softening point of the hydrogenated tackifying resin (C) is 80 to 200° C.
6. The acrylic pressure-sensitive adhesive composition according to claim 1 , wherein the acrylic polymer (A) contains, as a monomer unit, at least one type of monomer selected from the group consisting of N-vinyl cyclic amides, represented by the acrylic (1) described in the following general formula, and carboxyl group-containing monomers:
wherein, R 3 is a divalent organic group.
7. An acrylic pressure-sensitive adhesive layer comprising the acrylic pressure-sensitive adhesive composition according to claim 1 .
8. The acrylic pressure-sensitive adhesive layer according to claim 7 containing 40 to 90% by mass of a solvent-insoluble component.
9. An acrylic pressure-sensitive adhesive tape including the acrylic pressure-sensitive adhesive layer according to claim 7 .
10. The acrylic pressure-sensitive adhesive composition according to claim 1 , wherein an alicyclic hydrocarbon group in the (meth)acrylic monomer having an alicyclic structure has a bridged ring structure.
11. The acrylic pressure-sensitive adhesive composition according to claim 2 , wherein the hydrogenated tackifying resin (C) is a petroleum resin or a terpene resin.
12. The acrylic pressure-sensitive adhesive composition according to claim 3 , wherein the hydrogenated tackifying resin (C) is a petroleum resin or a terpene resin.