Process for making microcapsules

Abstract

Abstract PROCESS OF MAKING MICROCAPSULES OF ACTIVE CHEMICAL SUBSTANCES, FOR EXAMPLE, TO PREVENT VITAMIN A FROM AIROXIDATION, COATING PIGMENT PARTICLES IN CARBONLESS PAPER, ETC., WHICH CONSISTS OF (1) FORMING AN AQUEOUS EMULSION OR SUSPENSION OF THE ACTIVE CHEMICAL SUBSTANCE, (2) ADDING AN AQUEOUS SOLUTION OF A GELABLE HYDROPHILIC SUBSTANCE AND THEN SURFACE ACTIVE AGENT AND DISPERSING A LIQUID SOLVENT IMMISCIBLE WITH THE SAID EMULSION OR SUSPENSION OR (2'') DISPERSING A MIXTURE OF THE SURFACE ACTIVE AGENT AND THE LIQUID SOLVENT INTO THE AQUEOUS EMULSION OR SUSPENSION, TO FORM A DISPERSION AT A TEMPERATURE ABOVE A GELATIN POINT OF THE EMULSION OR SUSPENSION, (3'') RAISING THE DISPERSION TEMPERATURE TO AN INVERSION TEMPERATURE OR (3") IN CASE THE USED SURFACE ACTIVE AGENT IS MONO-VALENT METALLIC AND ADDING AN AQUEOUS SOLUTION CONTAINING MULTIVALENT METALLIC ION, TO INVERSE THE DISPERSION PHASE TO FORM DROPLETS, (4) STIRRING, (5) COOLING TO THE ABOVE SAID GELATION POINT TO CAUSE THE DROPLETS TO FORM MICROCAPSULES, (6) ADDING AN AQUEOUS ELECTROLYTE SOLUTION TO HARDEN THE MICROCAPSULES, (7) ADDING WATER-ABSORPTIVE SUBSTANCE TO COAT THE MICROCAPSULES OR (7'') WASHING AND DEHYDRATING THE MICROCAPSULES BY LOWER ALKYL ALCOHOLS, (8) FILTERING TO SEPARATE THE MICROCAPSULES, AND (9) DRYING THE MICROCAPSULES.

Inventors

• 👤 Nobuyasu Sato
• 👤 Ryota Oishi
• 👤 Toshio Nakamura

Bibliographic Details