TRANSPARENT DOUBLE-SIDED SELF-ADHESIVE SHEET
A transparent double-sided self-adhesive sheet is provided which, when bonding to an adhered, not only excels in the ability to conform to steps or surface irregularities caused by a printing site, but also excels in workability such as cutting processability. A transparent double-sided self-adhesive sheet is proposed, having an intermediate resin layer (A) and pressure-sensitive adhesive layers (B) as front and reverse side layers, each of the layers being a layer having one or more species of (meth)acrylic acid ester series (co)polymer as the base resin, in which transparent double-sided self-adhesive sheet, the shear storage elastic modulus (G′(A)) at a frequency of 1 Hz of the intermediate resin layer (A) is higher than the pressure-sensitive adhesive layers (B) in a temperature range of 0° C. to 100° C., and, the indentation hardness (ASKER C2 hardness) of the entire sheet is 10 to 80.
1 . A transparent double-sided self-adhesive sheet comprising a (meth)acrylic acid ester (co)polymer as a base resin, the sheet having an indentation hardness (ASKER C2 hardness) of 10 to 80, and having a creep of 1 mm to 15 mm,
wherein the creep is assayed by
a) adhering one side of the sheet to a vertically standing SUS plate wherein an adhesion surface area is 15 mm×20 mm,
b) curing the sheet under an atmosphere of 60° C. for 15 minutes,
c) applying a weight of 4.9 N to the sheet in the vertical direction, and then
d) measuring the creep of the adhesion position at the end of 60 minutes.
2 . The sheet of claim 1 , wherein the base resin comprises an acrylic acid ester (co)polymer comprising a randomly copolymerized monomer composition, the composition comprising a first monomer and a second monomer, wherein a homopolymer of the first monomer has a first glass transition temperature and a homopolymer of the second monomer has a second glass transition temperature, and the first and second glass transition temperatures differ by 25 to 300° C.
3 . The sheet of claim 1 , wherein the sheet is suitable for bonding two image display device structural members into one body.
4 - 13 . (canceled)
14 . The sheet of claim 2 , wherein the sheet is suitable for bonding two image display device structural members into one body.
15 . The sheet of claim 3 , wherein the two image display device structural members are (I) a protective panel and a touch panel, (II) a touch panel and a liquid crystal panel, or (III) a protective panel and a liquid crystal panel.
16 . The sheet of claim 14 , wherein the two image display device structural members are (I) a protective panel and a touch panel, (II) a touch panel and a liquid crystal panel, or (III) a protective panel and a liquid crystal panel.
17 . The sheet of claim 1 , comprising a single layer sheet.
18 . The sheet of claim 2 , comprising a single layer sheet.
19 . The sheet of claim 1 , comprising two or more layers, each layer comprising a (meth)acrylic acid ester (co)polymer as a base resin, wherein:
(i) the layers have nonidentical viscoelastic behaviors,
(ii) each layer is either (A) an intermediate layer or (B) a surface layer,
(iii) a shear storage elastic modulus at a frequency of 1 Hz of each intermediate layer (A) is greater than a shear storage elastic modulus of any surface layer (B) in the entire temperature range of 0° C. to 100° C., and
(iv) the indentation hardness (ASKER C2 hardness) of the entire sheet is 10 to 80.
20 . The sheet of claim 19 , comprising one intermediate layer (A) and two pressure-sensitive adhesive surface layers (B), wherein the intermediate layer lies between the two surface layers.
21 . The sheet of claim 20 , wherein the indentation hardness (ASKER C2 hardness) of the entire sheet is 10 to 60.
22 . The sheet of claim 19 , wherein the indentation hardness (ASKER C2 hardness) of the entire sheet is 25 to 80.
23 . The sheet of claim 20 , wherein the indentation hardness (ASKER C2 hardness) of the entire sheet is 25 to 80.
24 . The sheet of claim 20 , wherein a thickness ratio between the intermediate layer (A) and each pressure-sensitive adhesive surface layer (B) is 0.5<(A)/(B)<10, and a thickness of the pressure-sensitive adhesive surface layer (B) is 10 μm to 200 μm.
25 . The sheet of claim 21 , wherein a thickness ratio between the intermediate layer (A) and each pressure-sensitive adhesive surface layer (B) is 0.5<(A)/(B)<10, and a thickness of the pressure-sensitive adhesive surface layer (B) is 10 μm to 200 μm.
26 . The sheet of claim 20 , wherein the value of Tan δ (B) for each pressure-sensitive adhesive surface layer (B) is 0.4 to 1.4 in a temperature range of 0° C. to 100° C.
27 . The sheet of claim 21 , wherein a value of Tan δ (B) for each pressure-sensitive adhesive surface layer (B) is 0.4 to 1.4 in a temperature range of 0° C. to 100° C.
28 . The sheet of claim 20 , wherein the shear storage elastic modulus (G′) of the intermediate layer (A) is 5×10 3 to 5×10 8 Pa in a temperature range of 0° C. to 100° C., and wherein the relationship between the shear storage elastic modulus (G′(A)) of the intermediate layer (A) and the shear storage elastic modulus (G′(B)) of the pressure-sensitive adhesive surface layer (B) in a temperature range of 0° C. to 100° C. is:
1.1 <G ′( A )/ G ′( B )<80.
29 . An integrated image display device comprising the sheet of claim 1 .
30 . An integrated image display device comprising the sheet of claim claim 19 .