| 摘要 |
PURPOSE:To easily remove curling and to obtain excellent transparency and slipperiness by specifying a tandelta value, degree of orientation of the film plane, the average refractive index of the film, film haze, etc. CONSTITUTION:This film consists of a biaxially stretched polyethylene(PE)-2,6- naphthalate film. The tandelta value at 80'C by tensile viscoelasticity at 0.05Hz in the longitudinal direction of this film is <=0.08. The degree of orientation (DELTAP) of the film plane and the average refractive index (na) of the film satisfy equation 1.43Xna-2.148<=DELTAP<=1.43Xna-2.128. The number of pieces (A: piece/mm<2>) per 1mm<2> surface area of the film of the rugged units consisting of the projections by the particulates of the film surface and recesses of at least 3mum major diameter with these projections as nuclei satisfies equation 0<=A<=2500. The film haze is <=2.0% and the degree of sticking between film/film is class 3 or below. Such PE-2, 6-naphthalate is known and can be produced by the known method. |
