| 摘要 |
PURPOSE:To solve problems such as peeling of papers and so on a press-coat process and to obtain a moisture-resistant carton having excellent adhesive property and moisture resistance without blending waxes and adhesiveness imparting resin, by selectively using atactic polypropylene (APP) in a specific range of physical properties. CONSTITUTION:A moisture resistant layer of a moisture resistant carton consists of only atactic polypropylene (APP) and it is necessary that MW of the APP used for the moisture resistant layer is 100,000 or less. If the MW is smaller than 1,000 and too small, the adhesive property and the moisture resistance become unsufficient, and on the other hand, if the MW is larger than 100,000, flow characteristics as a paint for forming a moisture resistant layer on a paper become worse and it is not desirable. It is also necessary that the viscosity measured by means of B-type viscometer should be 1,000-100,000 CPS (at 150 deg.C). It is possible to improve furthermore the adhesive property and the moisture resistance better than APP alone by blending 5-15wt.% of isotactic polypropylene in APP as the moisture resistant layer.
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