Valtion Teknillinen Tutkimuskeskus

Pertti Tiitola

Pertti T&ouml;rm&auml;l&auml;

Soili Hellevi Peltonen

Harri Happonen

Geert Lammers

Jani Vuorenp&auml;&auml;

Jani Vuorenp{umlaut Over (aa)}

Process for the preparation of a starch ester, in particular a starch acetate, wherein a starch-based feedstock is reacted with an organic carboxylic acid anhydride in the presence of a catalyst. The reaction of the starch-based feedstock and the anhydride is performed at an excess pressure of about 0.1 to 50 bar in an essentially anhydrous medium containing 10% by weight of water at the most. As catalyst, sodium acetate, sodium hydroxide or sulphuric acid is used, and as the reaction medium, acetic acid or excess acetanhydride is used. By means of the invention, the duration of the esterification reaction can be significantly shortened, the separation of the product can be facilitated, and the recirculation of the waste solutions can be rendered more efficient.

Process for the preparation of a starch ester

The invention concerns a hydroxypropyl starch ester (HPS ester), compositions containing it, and a process for the preparation thereof. According to the invention, the molar substitution in the HPS ester is 2 at the most and the substitution degree in the ester group is at least 1. The HPS ester is prepared by hydroxypropylating a starch-containing base material in an aqueous alkanol medium. A starch component can be prepared of the HPS ester containing 90 to 60% by weight HPS ester and 10 to 40% by weight of a plasticizer. Compositions which are suited for, e.g., coating board or paper and for use as a component in labelling adhesives or paint, can be made from the starch component by combining it with auxiliaries known as such within the polymer and plastics technology.

Hydroxyalkylated starch ester and preparation and use thereof

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Rajamäki, Finland

Pertti Tiitola