Micro-capsules and method for their production
AssigneeMitsubishi Paper Mills Limited
InventorMitsuru Fuchigami
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Abstract
A hydrophobic material such as an oil solution of a dye is dispersed by the aid of a styrene-maleic anhydride copolymer to form an aqueous dispersion, then a melamine-formaldehyde precondensate is added into said dispersion and the mixture is heated and hardened to produce micro-capsules. These micro-capsules are proof against leakage or oozing of the hydrophobic material and uniform in shape and can serve excellently, for example, as dye capsules used for non-carbon paper.
Claims8
A method of producing micro-capsules containing a hydrophobic material comprising the steps of dispersing the hydrophobic material in an acidic aqueous solution of a styrene-maleic anhydride copolymer as dispersing agent or emulsifier for said hydrophobic material, adding to the dispersion a melamine-formaldehyde precondensate, and heating the mixture in a acidic state to harden the melamine-formaldehyde precondensate to form the wall of the microcapsule.
Dependencies are inferred from the claim text.