Optical adhesive tape

Abstract

The present invention aims to provide an optical adhesive tape for use in spliced ​​displays that arrange multiple image display devices in a tiled configuration. This ensures that even under certain operating conditions, the gaps between the multiple image display devices remain inconspicuous, and that transparency is maintained for a good appearance. The optical adhesive tape 10A of the present invention has a laminated structure comprising a substrate 1 and an adhesive layer 2. The substrate 1 has a first surface 1a and a second surface 1b, and the adhesive layer 2 is located on the first surface 1a of the substrate 1. After heating the optical adhesive tape 10A at 60°C and 90% relative humidity for 500 hours, the average dimensional change rate in its width and mechanical directions is within ±0.15%. The recovery rate of the adhesive layer 2, calculated in the following shear test, is less than 95%. <Shear Test> The strain A (%) and strain B (%) were measured, and the recovery rate (%) was calculated using the following formula. Strain A (%) is the strain after applying a torsional shear force of 500 Pa for 600 seconds from the top and bottom of a 2 mm thick, 7.9 mm diameter disc-shaped adhesive layer at 60°C. Strain B (%) is the strain after subsequently maintaining a shear force of 0 Pa for 1800 seconds. Recovery rate (%) = (Strain A - Strain B) / Strain A × 100

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