Transparent adhesive sheet and image display device including the same

A transparent adhesive sheet for applying a surface protective layer or a touch panel in an image display device to a display surface of an image display unit, or applying the surface protective layer to the touch panel, wherein

• the transparent adhesive sheet contains a copolymer of a monomer comprising:
• (A) an alkyl (meth)acrylate having an alkyl group of 4 to 18 carbon atoms,
• (B) a polar monomer whose homopolymer has a glass transition temperature (Tg) of 50° C. or higher, and
• (C) a (meth)acrylate ester (C-1) represented by the following formula (1), or a hydrophilic monomer (C-2) whose homopolymer has a glass transition temperature (Tg) of 10° C. or lower (which is a monomer other than the component (C-1) and a mass ratio of the component (B) to the component (C-2) is from 4:10 to 4:1):
• CH2═C(R)COO-(AO)p—(BO)q—R′ (1)
• wherein, in the formula (1),
• A is at least one kind of a group selected from the group consisting of (CH2)rCO, CH2CH2, CH2CH(CH3) and CH2CH2CH2CH2,
• B is at least one kind of a group selected from the group consisting of (CH2)rCO, CO(CH2)r, CH2CH2, CH2CH(CH3) and CH2CH2CH2CH2,
• R is a hydrogen or CH3
• R′ is hydrogen, or a substituted or unsubstituted alkyl or aryl group,
• p, q and r each represents an integer of 1 or more, and wherein the copolymer exhibits tan δ of 0.13 or more at 140° C. and 1.0 Hz, and also exhibits a storage elastic modulus of 8.9×104 Pa or less at 25° C. and 1.0 Hz.