Patent ID: 8039067

Claim:
A cellulous acylate film in which X-ray diffractive intensity satisfies the Formula (I) below and in which a half-value width of the peak at 2θ 2 is 2.8° or less as observed in the sectional view in a direction parallel to the longitudinal transport direction of the film: 0.60 ≦Ic i /Ic o ; Formula (I) wherein Ic i and Ic o are represented by the following Formula (IV) and (V) respectively: Ic i =Ic 11 /Ic 12 ; Formula (IV) Ic o ={( Ic 21 /Ic 22 )+( Ic 31 /Ic 32 )}/2; Formula (V) wherein Ic 11 to Ic 32 are obtained by the Formulae (II) and (III) below, Ic 11 and Ic 12 indicate Ic in a direction in which I 2 becomes the maximum in a diffraction picture observed in a direction perpendicular to the surface of the film and Ic in a direction perpendicular thereto respectively, Ic 21 and Ic 22 indicate Ic in a direction in which I 2 becomes the maximum in a diffraction picture observed in the sectional view in a direction parallel to the longitudinal transport direction of the film and Ic in a direction perpendicular thereto respectively, and Ic 31 and Ic 32 indicate Ic in a direction in which I 2 becomes the maximum in a diffraction picture observed in the sectional view in a direction perpendicular to the longitudinal transport direction of the film and Ic in a direction perpendicular thereto respectively: Iam=I 1 +{( I 3 −I 1 )/(2θ 3 −2θ 1 )}×(2θ 2 −2θ 1 ); Formula (II) Ic=I 2 −Iam; Formula (III) wherein when it is assumed that θ is the Bragg angle, 2θ 1 indicates 2θ at which the diffractive intensity becomes the minimum in the 2θ range of 4° to 5°, 2θ 2 indicates 2θ at which the diffractive intensity becomes the maximum in the 2θ range of 5° to 10°, 2θ 3 indicates 2θ at which the diffractive intensity becomes the minimum in the 2θ range of 14° to 16°, I 1 indicates a diffractive intensity at 2θ 1 , I 2 indicates a diffractive intensity at 2θ 2 , I 3 indicates a diffractive intensity at 2θ 3 ; wherein the X-ray diffractive intensity observed in the sectional view in a direction parallel to the longitudinal transport direction of the film satisfies the following Formula (VI): 0.40 ≦Ic /( Iam+Ic )≦0.85. Formula (VI)