Patent ID: 6727052
Filing Date: 2004-04-27
Classification: B32B,G03C,Y10T

Abstract:
A biaxially stretched, semicrystalline multilayer polyester photographic film base having at least two layers with the thickness of each layer being equal to or greater than 10 &mgr;m, said film base comprising:a) a main layer of a first PET-based polyester material, comprising one or more polyester resins, in which the total level of repeat units derived from 1,4-cyclohexane dimethanol is 2 to 100 mol %, based on the total glycol component in the main layer; b) an outer layer of a second PET-based polyester material, which outer layer comprises one or more polyester resins, in which material: the total level of repeat units derived from 1,4-cyclohexane dimethanol is 2 to 100 mol %, based on the total glycol component in the material; the total level of repeat units that is a salt of a sulfonic-acid-substituted aromatic dicarboxylate is between 2 and 10 mol % based on the total acid component in the material; and the total level of repeat units that is a polyalkylene glycol having an average molecular weight of 300 to 20,000 is between 3 and 10 wt % of the total polyester; wherein at least the polyester material in the outer layer is a semicrystalline polyester; and wherein the cutting index of said multilayer film base is less than 4.2 and the post process curl of said multilayer film base is less than 85 l/m.