DE2527457A1 - Colour reaction paper for automatic recording - contg. both microencapsulated reactants applied in one layer - Google Patents

Abstract

Automatically recording material, working on colour-reaction principle, contains both reaction partners in micro-encapsulated form, placed in one layer on paper surface. Premature colour formation, caused by damage to colour-former capsule walls by sharp edges of pigment particles, is prevented by using both colour-former and developer in micro-encapsulated form. The 2 reaction partners are encapsulated. The aq. capsule emulsions are mixed, applied to substrate and dried. A binder, e.g. polyvinyl alcohol, is opt. added.

Description

Hanover, June 3rd, 1975 PAT-75/20 ht-mb

Color reaction paper

Color reaction papers are coated papers that initially wear colorless coatings and with which only under the local writing pressure a colored, legible one Writing results from a color-forming reaction. Since you always have two for such a color-forming reaction Reaction partners are required, which may only be brought together under the effect of the writing pressure in such a way that In order to produce legible colored writing, it was first necessary to have 2 different coatings with the respective Make color reaction partners.

You tried early on. To find ways and means both reaction partners in a single layer (or in 2 superimposed, separate layers) accommodate, in such a way that these reactants initially clearly separated from each other and thus at the Color reaction were prevented and could only react reactively under the effect of the writing pressure.

It has been proposed for the coating of color reaction papers Emulsions with the same outer phases and different ones, only become one with one another during the writing process inner phases reacting with a dye on the paper substrate one after the other with the inclusion of a drying time or to apply mixed. (DBP 764 116);

The color formers were later microencapsulated. Each individual droplet of color former was given a dense capsule skin and was thus separated from his surroundings. Now attempts were made to use these encapsulated color formers in one layer to accommodate the reactant, namely an acidic clay. It turned out, however, that the very sharp-edged Pigment particles (clay particles) damaged or destroyed the thin capsule walls of the color-forming substance and that in this way a premature, unwanted color

609853/0540 - 2 -

reaction came about that made the whole product unusable made.

In the meantime one has now learned to encapsulate pigments as well, the present invention makes use of this possibility, which eliminates the disadvantage that sharp-edged pigment particles damage the capsule walls of the color-forming substance and can cause premature color formation.

The invention consists in the fact that the two partners required for the color reaction, namely both the color former the developer pigment is also applied in an encapsulated state mixed in a layer on the paper surface.

The coating is done as follows:

The two reactants are each encapsulated in a manner known per se. The aqueous capsule emulsions are mixed, applied to the carrier material and then dried. A binder such as. B. polyvinyl alcohol can be added, but is not absolutely necessary.

609853/0540

Claims (1)

Claim Self-writing recording material according to the color reaction principle, the reactants of which are housed together in a layer separated from one another, characterized in that,
that both reactants are microencapsulated. 609853/0540