Multicolor surface coatings have been used successfully for a number of years in both commercial and institutional applications. The original multicolor surface coatings were based on a water and organic solvent incompatibility. This incompatibility keeps the different colors separated, thus creating a multicolor system with one application of the surface coating. With the escalation of environmental concerns, there arose a need to reduce or eliminate the organic solvents in the system. In response to this need, water-born multicolor surface coating compositions were developed.
A major drawback of the prior art water-born multicolor surface coating technology is that special, expensive spray equipment is required to apply the prior art surface coatings. This special equipment is called "High Volume Low Pressure" (HVLP) equipment. It is required because when sprayed at pressures typical for other surface coatings, the prior art multicolored surface coatings lose their multicolor effect due to shearing of the different color particles in the coating into smaller particles, which then fuse together into a single color. It would be of great benefit to be able to use conventional spraying equipment to apply multicolor surface coatings. A multicolor surface coating which could tolerate higher shear forces would allow users of multicolor surface coatings to dispense with a second costly spraying system, as well as reduce the amount of equipment that would need to be transported. However, until the present invention, no such coating was available.
It was thus surprising and unexpected when the inventors discovered that the inclusion of a hydrophobic filler, such as a hydrophobic fumed silica, in the formulation of the water-born multicolor surface coating of the invention gave the coating much higher shear resistance, resulting in a product which can be sprayed at higher pressures than the prior art water-born multicolored surface coatings. The hydrophobic nature of the filler keeps the color particles separate from each other during spraying. The shear-resistant property of the present invention, as indicated above, will allow application of multicolored surface coatings with conventional high pressure spraying apparatus, allowing for significant economies of money and space. In addition to conventional spray equipment, the coating of the invention can also be sprayed with HVLP equipment.