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US 5,219,510 AGranted
Method of manufacture of cellulose ester film
AssigneeEastman Kodak Company
InventorsJulie S. Machell, I. Daniel Sand
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AssigneeEastman Kodak Company
InventorsJulie S. Machell, I. Daniel Sand
Estimating the term…
A cellulose ester film which can be melt cast is manufactured by esterfying cellulose to form a cellulose acetate or cellulose acetate propionate having degrees of substitution of DSac=1.9 to 2.6, DSpr=0 to 0.9 and DS.sub.OH =0 to 0.55 and melt compounding the resulting polymer with a non-volatile phosphoric acid ester. A film is formed by melt extruding the compounded polymer onto a cooling surface to form a solid film. The film is then biaxially oriented at 130.degree. to 200.degree. C. and a stretch ratio of 1.25.times. to 2.5.times. in both directions. The resulting product is a film of excellent properties such as surface smoothness, light transmission, low haze, low color, high elastic modulus and curl relaxation after aqueous processing. The melt cast film is useful as a photographic roll film to replace solvent cast cellulose triacetate.
The method of manufacture of a photographic roll film support which comprises
A method of manufacture of a photographic roll film support which comprises extruding a molten compounded cellulose ester at a temperature below about 250.degree. C. through a film-forming die onto a cooling surface to form a solid film, wherein said extruding step is carried out substantially in the absence of solvent, said compounded cellulose ester comprising (1) a cellulose ester of which the degrees of substitution are in the ranges, DS.sub.ac =1.9 to 2.6, DS.sub.pr =0 to 0.9 and DS.sub.OH =0 to 0.55, and (2) a phosphorice acid ester which is non-volatile at extrusion conditions and biaxially orienting the extruded film at a temperature from about 130.degree. to about 200.degree. C. and at a stretch ration from 1.25.times. to 2.5.times. in both directions of orientation.
Dependencies are inferred from the claim text.