Abstract: Changes in temperature and humidity over a long period of time lead to propensities for breaking the adhesive bond between adjacent tiles when the tiles are adhered together only at underfitting-overhanding boundary zones. Propensities for such malfunctioning are minimized by providing two sizes of tiles and laying the rectangular tiles so that in both rectangular directions, the adhesive paths across the floor area are not straight lines, but have offsets and staggers so that there is no straight line of adhesion longer than the length of one and one-half large tiles.

Abstract: A turquoise is impregnated with a monomeric diester having two spaced apart polymerizable monoolefinic groups, said diester having a plurality of supplemental hydrophillic groups and a volatility corresponding to a boiling point within a range from about 150.degree. C to about 300.degree. C. Whatever moisture may be sorbed on the turquoise is encapsulated within the plastic during the in-situ polymerization, inasmuch as such sorbed moisture can associate with such supplemental hydrophillic groups having an affinity for water. The dimethacrylate ester of triethylene glycol has two supplemental ether groups which tend to have affinity for water. Thus the monomer is sorbed on surfaces displacing any sorbed moisture in the internal pores or fissures in the turquoise, whereby the impregnation of the turquoise is feasible without critical control of vacuum drying and/or related preparatory steps.

Abstract: Laying floor tiles is more convenient because the floor tiles are provided with tongues which can be fitted readily into grooves in adjacent tiles because the depth of each groove is less than the magnitude of the portion of a tile which is overhanging a portion of the adjacent tile. Such overhanging and underfitting relationships supplement tongues along adjacent sides into grooves of two adjacent tiles. Peripheral floor tiles can be anchored, but central area tiles can be free from the conventional adhesion to the subflooring. Venting for moisture equilibration between the atmosphere and a sub-flooring such as a concrete slab is achieved because of the absence of adhesive between vertical walls of adjacent tiles.

Abstract: instead of following the conventional practice of removing the previous floor covering of sheet linoleum, floor tiles or the like, the floor tiles of the present invention are so remarkably thin that they are laid on top of the old flooring while still providing adequate clearance for doors, drawers, and related items imposing limits on the floor elevation. The principal layer has a thickness of organic composition from 0.005 inch (5 mils) to 0.040 inch (40 mils) and the cured transparent polyurethane top layer is at least 0.001 inch (1 mil) and not more than 10 mils in thickness. The combination of principal layer and top layer has a thickness from 0.010 to 0.045 inch. By keeping the flooring so thin, its usefulness for installation over existing flooring without exceeding the available clearance is enhanced.

Abstract: wood is disintegrated to prepare a mass of wood fibers which are formed into a mat. A unique hardboard is prepared by compressing a preformed mat comprising thermoplastic resins, wood fibers and wood fibers coated with such resins. The hardboard has a resin content of from about 37% to about 39% and a wood fiber content from about 53% to about 57%. The moisture content of the hardboard is ordinarily within a range from about 4% to about 10%, but such moisture content has the range expected for wood products under a wide range of temperatures, humidities, pressures and related variables. The thickness of the hardboard must be within the range from 790 to 850 microns and the density of the hardboard must be within the range from 690 to 750 milligrams per cubic centimeter. Heretofore such hardboard has been proposed for use as a facing lamina in multilamina composites for covering up various irregularities in the surface of the adjacent lamina while preserving a smooth facing surface.