PURPOSE: To obtain a resin plate having excellent transparency, high refractive index, low hygroscopicity, good dimensional stability and a beautiful appearance, by specifying the shape and degree of crosslinking of a crosslinked resin formed by using a specified styrene compound as a monomer component.
CONSTITUTION: A crosslinked styrene resin plate formed by using a compound of the formula (wherein R is H or methyl) as the main monomer component, wherein the thickness is 0.25mm or above, the width and the length are each 500mm or above, the surface is freed of partial irregularities, the inside is freed of air bubbles, and the degree of swelling is 10 or below. The degree of crosslinking of said resin plate is represented by a degree of swelling. A degree of swelling ≤10means that the resin is crosslinked to at least such a degree that the effect of improvement of the desired performances of the styrene resin can be realized. The degree of crosslinking is usually 0.02 or above. This crosslinked resin plate is preferably one having such a heat resistance that the deflection temperature under load according to ASTM D648 is 90°C or higher.
OTOBE KENDO
OZAKI HAJIME
