| 摘要 |
PURPOSE:An inexpensive sliding sheet for cassette, having low heat shrinkage and heat deformation, obtained by processing a straight-chain polyethylene into a sheet, heat-treating it, irradiating it with radiation, and crosslinking it to make a gel fraction in a specific range. CONSTITUTION:A low-density polyethylene, or middle-density polyethylene, or high-density polyethylene having <=250,000 weight-average molecular weight and preferably 0.01-5g/10min melt index is processed into a sheet by extrusion molding, heat-treated by a circulating hot air oven at 80-100 deg.C for 8-24hr, successively irradiated with radiation, and crosslinked to make the gel fraction of the sheet 20-60%. The prepared sheet has low shrinkage during heating, causes no heat deformation such as loss of tensity, winding, etc., has improved frictional characteristics, and is suitable as sliding sheet.
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