| 摘要 |
PURPOSE:To prevent the generation of a paper powder due to friction, etc., and the formation of a spot in a photosensitive sheet film by impregnating a specified amount of a thermoplastic resin in a base paper of a natural pulp. CONSTITUTION:The paper material is formed by impregnating a water soluble resin (D) or a solvent soluble resin (E) for an impregnating use, in a base paper (composed of the natural pulp type base paper) which is composed of the natural pulp (A) or a combination or an interior addition of said pulp (A) and a synthetic pulp (B) or a synthetic fiber (C) or is obtd. by adding said resin (D) to them. In this case, in order to maintain the property of the paper material, the preferable compounding ratio of the pulp is shown by the following formula, namely, (A):(B) or (C)=(100-30):(0-70) based on %. The addition amount of (D) to the pulp is 0-20%, and the impregnating amount of (E) to the pulp is 3-70% by weight basis. And, the preferable impregnating amount is 150-700g/m<2> for a protective sheet. Thus, the protective sheet reduces the generation of the paper powder from the surface and the section of said sheet. At the time of exposing the surface of a photosensitive sheet film, the shade due to a dust does not generate, thereby enabling the protective function of said film. |
