Color changing compositions using acids

#This invention relates generally to the field of coloring compositions and more particularly to a pair of coloring compositions which may be used in conjunction with each other to enable laying down an initial mark using an undercolor coloring composition yielding a first color and then using an overcolor coloring composition to enable a change of color of a portion or the entirety of the initial mark.

#Children enjoy various drawing and coloring activities using a variety of mediums. Useful in such activities are markers containing inks, crayons, pencils of various colors, and various paints including water colors, oil paints and acrylic paints. However, children would often like to change the color of a mark after they have made the mark. One instance would be the desire to add a yellow sun over a previously colored blue sky.

#Coloring compositions generally are mixtures of a coloring matter dispersed or dissolved in a carrier fluid. The colorant, if readily dissolving in the carrier fluid, is termed a dye. An insoluble coloring material is termed a pigment. Pigments are finely ground solid materials and the nature and amount of pigment contained in an ink determines its color. Coloring composition may also optionally include such ingredients as humectants, preservatives, bittering agents, and drying agents. Humectants function to improve freeze/thaw stability and to control drying out of the tip when the coloring composition is used as a marker ink. Preservatives serve the obvious function of preventing spoilage of the ink during the expected shelf life of the marker product. Drying agents speed drying of a mark laid down by a marker. Bittering agents impart the coloring composition with an unpleasant taste, so that children and animals will not consume the coloring composition.

#Examples of marking systems of the present invention when formulated as an ink are as follows. Quantities are in percent by weight of the total composition.

#______________________________________ Undercolor Color Ink Examples ______________________________________ Example 1 Example 2 Magenta Ink Yellow Ink Component % % ______________________________________ Deionized Water 74.00 74.00 Glycerin 20.00 20.00 Preservative Nuosept 95 .TM. 0.50 0.50 Premix 2.50 2.50 Dye Acid Red 92 3.00 -- Acid Yellow 1 -- 3.00 ______________________________________ Example 3 Example 4 Orange Ink Coral Ink Component % % ______________________________________ Deionized Water 74.50 74.50 Glycerin 20.00 20.00 Preservatives Nuosept 95 .TM. 0.50 0.50 Premix 2.50 2.50 Dye Acid Red 92 0.50 2.00 Acid Yellow 1 2.00 -- Pyranine 120 .TM. -- 1.00 NaOH (5N soln) -- 0.50 ______________________________________

#"Premix" in the previous and following examples is a mixture of 96.04% M-PYROL.TM., 1.98% PVP K-30.TM., and 1.98% TROYSAN POLYPHASE P-100.TM.. The inks of examples 1-4 had acceptable working properties. For examples 1-4, the pH ranged from 7.5 to 9.0 and the density ranged from 8.8 to 9.1 pounds per gallon. For examples 1-4, the viscosity ranged from 2.5 to 3.8 centipoise.