ES378121A1 - Piezosensible leaf coating based on capsules with support and starch aglomerant. (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

Pressure-sensitive record material comprises a supporting sheet having a coating on one surface, which coating includes starch granules, preferably ungelatinized, and pressure-rupturable micro-capsules containing a solution of a colourless basic chromogenic material that develops colour when reacted with an acidic material. The coating may also contain a binder, e.g. of gelatinised starch. The starch granules are preferably larger than the microcapsules and protect them from premature rupture. Other binders referred to are poly (vinyl alcohol), hydroxyethyl-cellulose, methylcellulose, carboxymethyl-cellulose, casein and ethylene-vinyl acetate copolymers. The microcapsules used in the Examples are of gelatingum arabic produced by coacervation and contain a mixture of chlorinated diphenyl and oil having dispersed therein, 3,3-bis(paradimethylaminophenyl)-6-dimethylaminophthalide alone or with benzoyl-leuco methylene blue. In Examples 1-4 the microcapsules contain the two dye-precursors, the granules may be from any of seven different plant sources or may be hypochlorite-modified, and the binder is a gelatinized hydroxyethylated starch. Example 5 uses polyvinyl alcohol solution as binder Example 6 applies the granules separately and Example 7 applies the binder separately, but these three are otherwise similar to Examples 1-4. In Examples 8 and 9 the microcapsules contain only the first dye-precursor, but the compositions are otherwise similar to Examples 1-4. In Example 8, the coreactive material is applied as a solution of paraphenylphenolformaldehyde resin and parachlorophenolparaoctylphenol-formaldehyde resin in toluene.