CS253329B1 - Process for preparring siccative on the base of cobalt compounds - Google Patents

Abstract

The solution relates to the preparation of an effective siccative agents with reduced cobalt content. It is technical problem of preparation of siccativating solutions agents containing rhodanocobalt complexes. The essence of the solution is that it is to a solution of the cobalt monocarboxylic acid salt having carbon numbers of 6 to 18 in the aliphatic or an aromatic solvent or an aromatic solvent thereof mixtures, containing 1 to 10% cobalt in dry matter works with potassium rodanide in a molar ratio cobalt salt / potassium rodanide = 1, in the presence ethylene glycol alkyl monoalkyl ether with the number of carbon atoms 1 to 4 and / or butanol

Description

The present invention relates to a process for the preparation of a cicalt compound driers.

Coating compositions based on drying oils or dehydrated or isomerized unsaturated fatty acids are usually siccated with cobalt compounds, most commonly isononates, naphthenates, octoates or cobalt resinates. In recent years, the world market has experienced an increasing cobalt shortage, which is reflected in an increasing trend in cobalt compound prices.

In the field of the desiccation of desiccant paints, no full replacement for cobalt dicotics has been found so far, therefore the development is heading towards effective cobalt-reduced siccating agents such as equimolar rhodanocobalt complexes and their solutions. Technology of production of these complexes has not been described yet.

We have now found that equimolar rhodanocobalt (II) complexes can be prepared by the process of the invention, consisting of a solution of the cobalt salt of a monocarboxylic acid having a carbon number of C 1. In the case of an aliphatic or aromatic solvent or mixtures thereof containing 1 to 10% of cobalt in the dry matter, treatment with potassium rhodanide is carried out so that the molar ratio of cobalt potassium rhodanide in the presence of monoalkyl esters of ethylene glycol with alkyl of 1 to 4; and / or butanol.

The composition of the solvents is governed by the nature and nature of the coating composition, the processing, storage and the like. The amount of solvents used is usually selected so that the cobalt content of the desiccant produced is at least 1%. Of the monoalkyl ethers, preferably monomethyl ether, monoethyl ether or monobutyl ether-ethylene glycol is used, and mixtures of these ethers with n-butanol or isobutanol containing at most 80% butanol are used. Sodium or ammonium rhodanide may also be used instead of potassium rhodanide, however, the solubility of the desiccant in some types of paints usually deteriorates.

The composition of the product is not influenced by the order of the substances used in the mixing vessel, but it is usually preferable to present the cobalt salt solution, optionally with solvents, and to dispense solid rhodanide. The reaction time is essentially limited by the rate of dissolution of the rhodanide in the reaction mixture, which is determined both by the composition of the solvents and by the temperature and by the intensity of stirring. Usually, stirring for 1 hour is sufficient to complete the reaction in the range of 20-30 ° C.

Příkla.dl

Weigh 2 g of potassium rhodanide, 23.6 g of cobalt naphthenate (containing 5% cobalt in the dry matter), 10 g of n-butanol and 5 g of ethylene glycol monoethyl ether in a 250 ml flat beaker. The mixture was stirred at room temperature for 1 hour when the dissolution of the rhodanide was complete. The desiccant contains 3.26% cobalt in the dry matter.

Example 2

A 500 ml flat beaker was charged with 11.8 g of cobalt octoate (containing 10% cobalt in dry matter) and 45.2 g of ethylene glycol monomethylether. At 25 [deg.] C., 2.0 g of potassium rhodanide are added with stirring, the mixture is stirred for 30 minutes, then diluted with 59.0 g of toluene and stirred for a further 10 minutes. The desiccant contains 1.05 cobalt in dry matter.

Example 3

Weigh 47.2 g of a solution (containing 5% cobalt metal), 20 g of butanol and 4 g of potassium rhodanide into a flat beaker. Stir at 25 ° C for 1.5 hours to dissolve the rhodanide. The desiccant contains 3.17% cobalt in dry matter.

Claims (1)

SUBJECT OF THE INVENTION Process for the preparation sikativačního agent based on cobalt characterized in that the ro2tok cobalt salt of a monocarboxylic acid having a carbon number to C _g in aliphatic or aromatic solvents or mixtures thereof, containing from 1 to 10% cobalt in the dry residue was treated with potassium thiocyanate in a molar ratio of cobalt a potassium rhodanide salt in the presence of a monoalkyl ether of ethylene glycol with an alkyl number of 1 to 4, and / or butanol.