METHOD OF PRODUCING COMPOSITIONS OF A HOT-MELT WATER-BASED COATING Russian patent published in 2020 - IPC C08J3/03 C09D123/08 C09J123/08 C08L23/08 

FIELD: chemical or physical processes.

SUBSTANCE: invention relates to a method of producing a water-based composition of a hot-melt coating. Method comprises steps of: a) mixing in molten ethylene vinyl acetate copolymer and at least one agent for increasing adhesion in mixing and transfer zone to produce molten mixture, b) contacting the molten mixture with the initial aqueous stream containing the neutralizing agent, water and the surfactant in the emulsification zone to obtain a dispersion and c) diluting the dispersion with water in the dilution zone to produce a water-based hot-melt composition. Method is a continuous method and can be carried out in an extruder and involves adding a wax to produce a molten mixture at step a). Mixing and transfer zone is operated at temperature from 140 to 160 °C, and emulsification zone is operated at temperature from 80 to 120 °C, and the neutralizing agent is potassium hydroxide. Water-based composition of the hot-melt coating has degree of neutralization of acid groups from 25 to 70 mol % relative to the total content of the acid in the composition of the hot-melt water-based coating. Water-based composition of the hot-melt water-based coating contains 40–80 wt % water. Content of ethylene vinyl acetate ranges from 50 to 85 wt % and content of agent for increasing adhesiveness is from 6 to 20 wt % relative to total weight of solid substances in composition of hot-melt coating on water basis.

EFFECT: technical result is providing an economical method of producing compositions of a hot-melt water-based coating while maintaining or improving the quality and characteristics of the hot-melt coating when carrying out a continuous dispersion process with a short residence time for substantially reducing EVA hydrolysis.

9 cl, 7 tbl, 1 dwg, 4 ex