Transparent adhesive sheet and image display device

摘要

Provided is a novel transparent adhesive sheet with which the cut edge is not sticky over time when a laminated body that has been bonded via the adhesive sheet is cut, which can be adhered without generating residual air bubbles, even when the surface of an adherend is uneven, and which can be adhered without foaming, even when the adherend is a material such as plastic that can generate outgas. Suggested is an adhesive sheet that has one or more layers of a first adhesive layer and one or more layer of a second adhesive layer that exhibit different viscoelastic behaviors, and has an integrated structure whereby these layers are laminated, with a dynamic shear storage modulus G′ of 2×104 to 5×105 Pa for G′(20° C.) and 1×104 to 1×105 Pa for G′(150° C.) when measured with a 1 Hz frequency temperature dispersion.

主权项

1. An image display device, comprising:
a glass protective panel; a polarized film; and a laminate comprising a transparent adhesive sheet disposed between the protective panel and the polarized film; wherein: the glass protective panel is an outermost layer of the image display device; the glass protective panel has a thickness of 0.8 mm or greater; the transparent adhesive sheet comprises:
at least one first adhesive layer; andat least two second adhesive layers; the first adhesive layer exhibits different viscoelastic behavior from the second adhesive layers; the first adhesive layer and the second adhesive layers are integrally laminated in an order of second adhesive layer, first adhesive layer, second adhesive layer; the second adhesive layers are formed from a composition comprising an acrylic acid ester polymer and a cross-linking agent selected from multifunctional organic functional group resins having two or more organic functional groups selected from an isocyanate group, an epoxy group, a melamine group, a glycol group, a siloxane group, and an amine group; and a dynamic shear storage modulus G′ (measured with use of a device for measuring viscoelasticity in a shear method under the conditions Jig: Φ25 mm parallel plate, strain level: 0.5%, frequency: 1 Hz, temperature: −70 to 200° C. (measured at 3° C./min temperature elevation rate from −70° C.), sample thickness: 250 μm) of the transparent adhesive sheet is within the ranges below when measured with a 1 Hz frequency temperature dispersion: G′(20° C.) is 2×104 to 5×105 Pa; and G′(150° C.) is 1×104 to 1×105 Pa.