(Melt-) extrusion process for the preparation of alkali metal carbonate, bicarbonate and sesquicarbonate formulations using a melted functionalizing agent

A process for preparing a formulation comprising an alkali metal salt selected from the group consisting of alkali metal bicarbonate salts, alkali metal carbonate salts, alkali metal sesquicarbonate salts and combinations thereof, wherein said process comprises the steps of:

• (a1) melting a functionalizing agent to a temperature above the melting point of the functionalizing agent to obtain a melted functionalizing agent, and mixing the melted functionalizing agent with the alkali metal salt to obtain a paste-like composition;
• or
• (a2) mixing the functionalizing agent and the alkali metal salt to obtain a mixture, and heating the mixture to a temperature above the melting point of the functionalizing agent to melt the functionalizing agent within the mixture and to obtain a paste-like composition;
• or
• (a3) mixing the functionalizing agent and the alkali metal salt to obtain a mixture, and, to obtain the formulation,
• (b1) extruding or melt-extruding the paste-like composition obtained in step (a1) or (a2), or
• (b2) melt-extruding the mixture obtained in step (a3) at a temperature above the melting point of the functionalizing agent to melt the functionalizing agent to obtain a paste-like composition during extrusion,
• wherein the paste-like composition undergoing extrusion comprises at least 25% by weight of said alkali metal salt, based on the total weight of the composition undergoing extrusion, and the functionalizing agent,
• wherein the functionalizing agent is selected from the group consisting of oils, fats, resin acids and esters and salts of oils, fats, resin acids and esters, fatty acids, fatty acid esters, and fatty acid salts other than calcium stearate, waxes, shellac, poly(methyl)methacrylates, and combinations thereof,
• wherein the waxes comprise from 16 to 46 carbons,
• wherein at steps (a1) or (a2) or (a3), the weight ratio of the functionalizing agent is at least 30 parts per 100 parts of the alkali metal salt.