Process for forming decorative surface coverings

Claim 1

A process for producing a surface covering having a decorative multi-level wear layer comprising 1. depositing at least one layer of unfused thermoplastic granules of resinous dryblend onto a releasable substrate; 2. heating the dryblend to cause partial melting of at least surface portions of the granules at their points of contact thereby forming bonds between adjacent granules to form a cohesive, porous layer having an upper and a lower surface; 3. producing a design on said cohesive, porous layer by applying a plurality of differently colored settable resinous inks to the upper surface thereof, each colored ink being successively printed one over the other to cover a larger surface area than the area covered by a preceding printed colored ink, each of said inks being applied in amounts and viscosities sufficient to result in penetration thereof through at least 10% of the thickness of the cohesive, porous layer at the points of application in areas not penetrated by a previously applied ink, the penetration of each colored ink varying to a predetermined degree with the lateral dimensions of its area of coverage and each preceding colored ink being positioned perpendicularly within the boundary of the area covered by the next printed color, resulting in ink-containing and non-ink-containing areas in the cohesive, porous layer in both a direction laterally across the surface of the sheet and in a direction transversely through the sheet from the upper surface to the lower surface thereof; 4. applying a backing to the upper surface of the printed, porous layer to which said settable resinous inks were applied; 5. heating to a temperature below the fusion temperature of the dryblend to set the inks; 6. removing the releasable substrate; 7. removing the non-ink-containing portions of the cohesive, porous layer from the side formerly in contact with the releasable substrate while leaving the ink-containing portions thereof substantially unaffected; and 8. heating to fuse all of the remaining resinous material in the composite structure thereby forming a decorative, multi-level, wear layer wherein each of the colored ink-containing design elements extends from the backing to varying levels with respect thereto.