1. Field of the Invention
This invention relates to a liquid composition for metachromatic members, and a metachromatic member set making use of the composition. More particularly, it relates to a liquid composition for metachromatic members which is used to form desired images on metachromatic members, and a metachromatic member set making use of the composition.
2. Related Background Art
Conventionally, as an attempt to form images on metachromatic members, a doll- or animal-shaped toy set is disclosed which comprises a doll- or animal-shaped toy and a water-metachromatic member comprising a support and provided thereon a porous layer formed by fixing therein a low refractive index pigment in a disperse state together with a binder resin (see, e.g., Japanese Patent Application Laid-open No. 11-216272).
In the above doll- or animal-shaped toy set, any desired portion of a doll- or animal-shaped toy in a liquid-absorbed state is pressed against the surface of the water-metachromatic member to make the porous layer permeated with water and turn transparent or semitransparent so as to make an image visible. The toy has the repetition utility that, upon evaporation of the liquid having permeated the porous layer, the porous layer returns to the original state and the image comes invisible.
It is also disclosed therein that water is preferably applied as a medium which makes the toy liquid-absorbed and that, in order to control drying speed to elongate image visual time, a water-soluble organic solvent such as propylene glycol may be mixed in a very small quantity.
However, the image formed in the water-metachromatic member constituted as described above is one which turns invisible upon evaporation of the water and, even when the water-soluble organic solvent such as propylene glycol is added, the image visual time is a little elongated at best.
Hence, such a means is unsuitable for uses in which images are permanently formed and preserved, e.g., uses in which impressions of hands, feet and the like of infants are taken and preserved. Accordingly, a liquid composition suited for the preservation of images has eagerly been awaited.