Water soluble crayons are a very versatile art medium. They can be used on a variety of surfaces, including paper, drafting film, fabric, and wallpaper. Unlike traditional wax-based crayons, water soluble crayons are also easily washable from fabrics, paint, and even upholstery.
The compositions of the present invention provide performance compared with prior art water soluble crayon formulations. Among the properties of the compositions are good adhesion, low tackiness after hardening, and a wide range of desirable marking characteristics.
To prepare a water soluble crayon, a mixture of alkoxylation products is combined with an illustrative pigment. This mixture is then melted in an oven at 80degC. After cooling, the composition is placed into a mold. It can then be removed from the pouring equipment or from the processing equipment.
In addition to the coloring agent, a preservative is added to the composition. This preservative is propyl paraben. Other additives may include stabilizers, flavors, or glitter ingredients.
Typical ingredients for the compositions of the present invention include a primary monohydric alcohol, an active hydrogen, and a oxyalkylene moieties. Pyrazolone dyes are also very useful. However, the optimum level of alkoxylation should provide a narrow distribution of alkoxylate species.
The amount of water soluble alkoxylation products should be sufficient to impart breaking strength of at least 1,200 grams. This should enable a narrow distribution and a desirable balance of performance properties in the composition.
Several different types of organic compounds can be used to produce a broad spectrum of alkoxylate species. In general, the common alkoxylate ratio is one mole of oxyalkylene per mole of active hydrogen site.
