Microcapsules, printing inks and their production
AssigneeThe Standard Register Company
InventorMichael E. A. Seitz
Life of this patent
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Abstract
Microcapsules having hard, thick walls are formed by dispersing an oily solution containing a crosslinking agent in an aqueous solution, and forming a polysalt in the aqueous solution, the polysalt including a high molecular weight polyanion and a polycationic polyamine having a functionality of at least three. The polyanion is preferably casein. If the surface of the microcapsules formed in the aqueous solution is lipophilized, the microcapsules easily separate from the solution by filtration. By use of a suitable wetting agent, the filter cake can be used in place of the pigment in any conventional printing ink. The microcapsules may be used in carbonless copy paper technology.
Claims18
A process for the production of microcapsules containing an oily solution, comprising:
- dispersing an oily solution including a crosslinking agent into an aqueous solution;
- forming a polysalt in said aqueous solution, said polysalt including a high molecular weight polyanion which can be made substantially nonpolar by reaction with a lipophilizing agent and a polycationic polyamine having a molecular weight of less than 1200 and having a functionality of at least three, whereby a hard, thick layer is formed around droplets of said oily solution and microcapsules are produced, and
- adding a sufficient amount of a lipophilizing agent to cause the outer surface of said microcapsules to become substantially nonpolar.
A process for making a printing ink comprising:
- mixing a printing ink vehicle with a wetting agent, and
- adding a filter cake of microcapsules prepared by the process of
- dispersing an oily solution including a crosslinking agent into an aqueous solution;
- forming a polysalt in said aqueous solution, said polysalt including a high molecular weight polyanion and a polycationic polyamine having a functionality of at least three, whereby a hard thick layer is formed around the droplets of oily solution and microcapsules are produced.
- adding a sufficient amount of a lipophilizing agent to cause the outer surface of said microcapsules to become substantially non-polar, and
- filtering said microcapsules from said aqueous solution to obtain the filter cake of microcapsules.
Dependencies are inferred from the claim text.