PROCESS FOR PRODUCING ORIENTED FILM

摘要

[OBJECT]

Disclosed is to provide a process for producing a film by using a raw material comprising a polyethylene having a density of 900 to 980 kg/m<Sup>3</Sup> or a polypropylene, whereby improving the productivity at the time of producing the film by a stretch molding. Further the film is obtained without impairing the optical characteristics and mechanical characteristics, which are intrinsic characteristics of polyethylene or polypropylene.

[SOLVING MEANS]

A process for producing a film by a stretch molding of a mixture comprising a polyethylene and a polyethylene wax, the polyethylene having a density of 900 to 980 kg/m<Sup>3</Sup> and an MI of 0.01 to 100 g/10-minutes as measured at 190°C and a testing load of 21.18 N in accordance with JIS K7210 or a polypropylene, and the polyethylene wax having a density of 890 to 980 kg/m<Sup>3</Sup> and a number-average molecular weight (Mn) of 500 to 4,000 as measured by the gel permeation chromatography (GPC) and satisfying the relationship shown by the following equation (I). <MathDetails id="matha01" num="(i)"><MathText><![CDATA[ <math display="block"><mi mathvariant="normal">B</mi><mo mathvariant="normal">≤</mo><mn mathvariant="normal">0.0075</mn><mo mathvariant="normal">×</mo><mi mathvariant="normal">K</mi></math><img id="ia01" file="imga0001.tif" wi="61" he="9" img-content="math" img-format="tif" /> ]]></MathText></MathDetails>
(In the above formula (I), B represents the weight ratio (% by weight) of a component having a molecular weight of 20, 000 or more in terms of polyethylene as measured by the gel permeation chromatography in the polyethylene wax, and K represents the melt viscosity (mPa·s) of the polyethylene wax at 140°C.)