| 摘要 |
PURPOSE:To obtain a sheet having neither generation of crease nor large shrinking in a longitudinal direction of a glass bottle along with prevention of generation of cracks due to hot water treatment, by making use of the material which is a stretched sheet obtained by extrusion molding from polyethylene resin containing a polybutadiene block aggregate, and possesses specific characteristics. CONSTITUTION:A material which is a stretched sheet obtained by extrusion molding from polystyrene series resin which contains a 10-40wt% polybutadiene block aggregate whose diameter is 0.05-0.01mu and possesses shrinking ratios in the directions of a flow and width which are more than 30% and 5-25% respectively and the shrinkage starting temperature in the direction of the width which is higher by 3 deg.C than that in the direction of the flow is used for the titled sheet. As for stretching processing for giving the foregoing shrink properties, for example, stretching processing in the directions of the flow and width are performed separately, which is to be desired that the stretching processing in the direction of the flow is performed after the stretching processing in the direction of the width has been performed. Then the stretching is applied to the sheet by setting up a stretching temperature at the time of the final stretching processing in the direction of the flow higher by 3 deg.C than the final stretching temperature along with setting up of the final stretching temperature at the time of stretching processing in the direction of the width higher than the heating deformation temperature. |
