| 摘要 |
PURPOSE:To provide the manufacture method of low shrink biaxially oriented film, which has no uneven orientation and is excellent in thickness accuracy, out of resin mainly of linear low density polyethylene. CONSTITUTION:Un-oriented linear low density polyethylene sheet is stretched under the condition that the draw ratio at least either in machine direction or in transverse direction is not less than 300% and less than 800% and the product of the draw ratios in both the directions is not less than 900% and less than 5.000%, and, after that, heat-treated so as to produce low shrink polyethylene-based biaxially oriented film. In this case, its orienting temperature conditions are set to stisfy the following numerical formula (n1) and (n2) and its heat treating temperature condition is set to satisfy the following numerical formula (n3):(n1)...Tm-30 deg.C<=T1<= Tm-10 deg.C, (n2)...Tm-50 deg.C<=T2<=Tn-25 deg.C, (n3)...Tm-40 deg.C<=T3<=Tm, in which T1 represents the lengthwise orienting temperature, T2 represents the crosswise orienting temperature and T3 represents the heat treating temperature. |
