Acrylic adhesive is used to fill protective panels

Recently, in order to protect the display panels in flat panel displays such as plasma displays (PDPS), liquid crystal displays (LCDS), organic EL displays, and field emission displays (FED), The structure of the surface of the display panel with good impact resistance, such as acrylic or polycarbonate panels, or with protective panels (protective panels), such as tempered glass, has been paid attention to.

Most such protective panels have a structure designed to prevent damage by placing an empty wall between the protective panel and the display panel so that the impact applied to the surface protective panel does not transfer directly to the display panel. However, there are problems with the empty wall causing ghosting images or limiting film formation through multiple reflections. For this reason, a method of filling the empty wall between the protective panel and the display panel (empty wa11) with, for example, a highly transparent pressure-sensitive adhesive layer has been proposed recently. As a pressure-sensitive adhesive with good transparency, the acrylic pressure-sensitive adhesive is usually used. As a polymer used in the acrylic polymer which constitutes such a pressure-sensitive adhesive, a combination of acrylic monomer and a cohesive component, such as acrylic acid, which has a base, is often used.

At the same time, the trend of touch-panel displays as display systems have received much attention. In this case, for example, when the above pressure-sensitive adhesive such as acrylic containing an antelope base is used to fill a blank wall between the front protective panel (also used to prevent damage to the display panel) and a display panel on which transparent electrodes such as ITO(steel tin oxide and tin oxide) are arranged on the surface, Corrosion in the transparent electrode layer with time and functional deterioration of the touch panel in response to changes in electrical impedance are expected.

In addition, when the pressure-sensitive adhesive is laminated with a resin board, such as an acrylic or polycarbonate board, it may require such properties (float stripping resistance, i.e. no stripping or buoyancy by bubbles generated from the resin board occurs at the bond interface under engraving conditions. However, the pressure-sensitive adhesive disclosed in the above patent literature does not involve sufficient buoyance-stripping resistance compared to a pressure-sensitive adhesive that contains a monomer with an antelope base as a monomer component.