Abstract: Thin films are produced by a process in which organic polymers having long-chain side groups are dissolved in an organic solvent, the solution is spread at the water/air interface by the Langmuir-Blodgett technique and the film is transferred onto a solid base material after evaporation of the organic solvent, and the organic polymers used are those which contain long-chain n-alkyl side groups bonded to the main chain of the polymer via polar groups, and some of these long-chain n-alkyl side groups are replaced by shorter-chain n-alkyl side groups, by branched alkyl side groups having the same or a smaller number of carbon atoms or by equally long or shorter side groups having one or more C-C multiple bonds.This process can be used to produce film elements, for example for optical filters.

Abstract: Thin films which contain a defined concentration of dye per unit area and are useful as layer elements, e.g. for optical filters, are prepared by spreading an oleophilic dye which is soluble in an organic water-immiscible solvent and an organic polymer dissolved in an organic solvent as a thin film at the water/air interface and, after the solvent has evaporated, transferring said film by the Langmuir-Blodgett technique to a solid base material.

Abstract: Preparation of a starch ester having an Mn of 1000-50,000 and a degree of substitution of 0.4-3.0 by heating a mixture of starch, a Cl-7 monocarboxylic acid, water, and optionally a catalyst and meanwhile withdrawing water until the ester being formed has attained the desired degree of substitution. Optionally remaining free hydroxyl groups may be esterified by reaction with a carboxylic anhydride of -halide. The resulting solution may be treated to neutralize remaining free monocarboxylic acid by mixing it with an esterifiable hydroxyl compound and esterifying it at 40.degree.-270.degree. under the removal of water. In this way, use is made of cheap ingredients, and the resulting product is suitable for immediate use in a number of applications, e.g., as binder in coating compositions.