Cellulose acylate solution, producing method thereof, and solution casting method

Abstract

The invention provides a cellulose acylate solution, a producing method thereof, and a solution casting method, performing sampling to the concentrated liquor that the TAC (48) is dissolved in the solvent (49). About the concentrated liquor for sampling, the determined molecular weight is greater than 500 and less than 1000; and the methylene takes at least 80% of aliphatic ester in the molecular weight. When the quality proportion is greater than 0.01%, sampling is performed for the concentrated liquor. The pH is calculated according to the concentrated liquor for sampling, when the pH is not less than 5 and greater than 3, the pH is adjusted to be less than 5 and greater than 3. The pH adjustment is performed by adding acetic acid or natrium aceticum to the solvent (49); and the adjusted pH concentrated liquor is heated so as to maintain the temperature between 80 DEG C to 90 DEG C.

Description

technical field [0001] The invention relates to a cellulose acylate solution, a manufacturing method thereof, and a solution film-making method. Background technique [0002] As is well known, the solution film forming method is a method of casting a dope in which a polymer is dissolved in a solvent on a support to form a cast film, peeling off the cast film as a wet film, and drying to produce a film. Cellulose acylate films, which are often used for optical applications, are produced by this solution film-forming method. In recent years, with the rapid market expansion of liquid crystal displays, the demand for cellulose acylate films as viewing angle widening films and polarizing plate protective films constituting liquid crystal displays has also rapidly increased. Therefore, it is necessary to greatly increase the production amount of cellulose acylate film from existing facilities. [0003] In order to increase the film production with the existing solution film form...

AI Technical Summary

Problems solved by technology

However, even by the method of Japanese Patent Laid-Open No. 2006-199029, precipitation may occur

The methods of Japanese Patent Laid-Open No. 2008-063403 and Japanese Patent Laid-Open No. 2009-161702 can sometimes prevent precipitation, but even with this method, precipitation still sometimes occurs, so it cannot be said to be a method for completely suppressing precipitation.

In addition, when the so-called cold casting of the casting film is cooled and solidified on the support, the precipitation is particularly easy to occur.

That is, the conventional cleaning method is also effective in suppressing precipitation, but there are also components that cannot be removed

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