Cellulose acylate, cellulose acylate film, and method for production and use thereof
AssigneeFuji Photo Film Co., Ltd.
InventorsToyohisa Oya, Saisuke Watanabe
Life of this patent
Estimating the term…
Abstract
A cellulose acylate solution containing a cellulose acylate which satisfies 2.5≦A+B≦3, 0≦A≦2.5, 0.3≦B≦3 (wherein A is the substitution degree of an acetyl group, and B is the sum of the substitution degrees of an acyl group having 3 to 7 carbon atoms) and whose content of sulfur atoms of residual sulfate moiety S is such that 50 ppm<S<500 ppm. When solution casting is carried out using this solution, a cellulose acylate film having good surface state and low peel-off load can be produced.
Claims38
A method for production of cellulose acylate satisfying the requirements of (1) to (3) below:
- (1):
- 2.5≦A+B≦3
- (2):
- 0≦A≦2.5
- (3):
- 0.3≦B≦3
- wherein A represents the substitution degree of an acetyl group, and B represents the sum of the substitution degrees of an acyl group having 3 to 7 carbon atoms, and
- comprising at least
- 1) contacting cellulose with a carboxylic acid having 2 to 7 carbon atoms and maintaining the system at 20° C. to 100° C. (pretreatment process);
- 2) acylating the cellulose obtained after the pretreatment process, with an acylating agent in the presence of a sulfuric acid catalyst (acylation process);
- and
- 3) maintaining the reaction mixture at 30° C. to 100° C. for at least 1 hour in a state where base is present in a stoichiometric excess with respect to sulfate moiety (post-heating process), the post-heating process being carried out in any step between after the acylation process and before re-precipitation.
A cellulose acylate solution satisfying the requirements of (1) to (3) below, and containing a cellulose acylate having an amount of residual sulfate moiety such that 50 ppm<S<500 ppm, wherein S is the content of sulfur atoms of the residual sulfate moiety:
- (1):
- 2.5≦A+B≦3
- (2):
- 0≦A≦2.5
- (3):
- 0.3≦B≦3
- wherein A represents the substitution degree of an acetyl group, and B represents the sum of the substitution degrees of an acyl group having 3 to 7 carbon atoms.
Dependencies are inferred from the claim text.