GB2152098A - Surface covering material - Google Patents

Abstract

A floor tile or sheet is manufactured by adding a hard particulate material of contrasting colour such as ground marble to the tile base plastics mix, which then appears in the surface of the finished tile as an unoriented, unsmeared dot pattern.

Description

SPECIFICATION Surface covering material The invention is directed to a surface covering material, more particularly to a floor tile with a non-directional pattern.

Various proposals have been made in the past for the manufacture of surface covering materials with a non-directional pattern. To have such a pattern is of special importance in a covering such, for example, as a floor tile which is normally square so that when a plurality of tiles is laid they may be positioned with random quadrant orientation without some tiles appearing to have a pattern oriented in a direction at right angles to others.

U. S. Patent 3,145,241 is directed to a floor covering material with a non-directional pattern which is accomplished by limiting the number of granules added to the base.

U. S. Patent 2,624,068 is directed to a non-directional pattern in a floor covering material wherein the particles are compressed in two directions normal to one another to prevent directional orientation.

U. S. Patent No. 3,194,856 is directed to a non-directional pattern in a floor covering material, and this is accomplished by using one hot and one cold calender roll with the cold roll contacting the particles.

U. S. Patent No. 2,995,179, the entire disclosure of which is incorporated by reference herein, shows the use of ground limestone as a filler in a tile, but not as a decorative material.

U. S. Patent No. 2,663,663 does not deal with a tile-making process, but the patent does disclose the addition of crushed marble to a thermosetting synthetic resin laminate. The crushed marble is not added to produce a pattern, but is instead added to provide a roughened surface.

Finally, U. S. Patent No. 2,120,281 shows the use of hard silica gel in a rubber battery separater which is subsequently vulcanized but, again, the silica gel is not included for decorative purposes.

The present invention provides a flat thermoplastic tile having a first coloration, at least one primary surface area of the tile having distributed therein a plurality of particles of 10 to 60 U.S. Standard Mesh size, the particles being of a second coloration, different from the first, and being unoriented and free from smearing.

By a flat tile is meant one whose dimensions in two directions at right angles are substantially greater than its dimension in a third direction at right angles to the other two, and a primary surface is one that extends in the first two directions.

In one embodiment the invention is directed to an improved composition comprising a filled plastic mass of a first or primary coloration having a thermoplastic binder system and a filler.

The tile is formed from this mass in a flat sheet shape and one primary surface thereof is regarded as the wear surface, and this is the surface of the tile which faces upward when the tile is installed on a floor. The tile has a plurality of particles of 10 to 60 mesh size distributed in the surface area of the tile. The particles are of a contrasting coloration to the plastic mass coloration and are in a circular unsmeared shape. The particles are advantageously marble particles which are not smeared or directionally oriented during the calendering operation which forms the floor tile.

The preferred method of making the product is the forming of the filled plastic mass with the marble particles and then calendering the mass into a sheet form and, from the sheet, cutting a plurality of 12" x 12" (30 cm x 30 cm) or like floor tiles. Many of the marble particles appear in the surface of the tile product and have not been smeared or elongated during the calendering operation, but do appear as small dots of a contrasting color on the surface of the tile product.

The tile product of the invention herein is conveniently made by a process very similar to that carried out in the prior art in U. S. Patent No. 2,995,179. The materials are mixed in a Banbury or like intensive mixer, dropped on a sheeting mill and passed through hot calender rolls to form a sheet of the final thickness which is then cut to desired tile dimensions.

A typical composition for use in the manufacture of a tile in accordance with the invention is the following, having proportions set forth as follows: Ingredient Percent by Weight Resin: A mixture of 33% by weight of polyvinyl chloride and 67% by weight of a 90-10% blend of polyvinyl chloride and polyvinyl acetate 13.6 Ground limestone (40 mesh 8 finer) 71.6 Colored marble (10-60 mesh) 8.0 Plasticizer (dioctyl phthalate) 4.5 Process Aid (alpha-methyl-styrene) 1.0 Stabilizer (melamine base with a metallic soap) 0.8 Pigment (titanium oxide) 0.5 100.0 The raw materials are charged in a standard manner into a Banbury or like intensive mixer. All the colored marble is added after all the other materials have been blended together. The color of the marble is a contrasting color to that of the pigment for the tile product.The material is then sheeted out in a conventional manner as set forth in U. S. Patent 2,995,179.

The roll separating forces during the milling operation provide a pressure of about 3.2 tons per linear inch (about 1250 kN/m) width at the time the mass of plastic material is formed into a sheet. It is during the application of pressure of this magnitude that the hard particles must not be smeared into a directional pattern.

The finished product provides a unique non-dirctional tile pattern. The calendering operation does not smear or elongate the marble particles as it would do in a normal tiling operation of the prior art where the contrasting colored particles are of a soft thermoplastic material, and this tends to elongate or provide a smeared line effect on the finished product. The product according to the invention has a rather uniform dot or circular contrasting color spot. In effect the product visually resembles the result of sprinkling ground black pepper, or other contrasting color particles, relatively uniformly across the surface of a white or light color tile base. A smeared tile product produced in accordance with the prior art has a directionality in that the tile seems to extend in the direction of the smearing.In a product in accordance with the present invention there is no smearing and therefore the tile may be turned in any one of the four standard quadrants and not appear to have a directionality in its dot design.

The dot pattern of the finished product may if desired be enhanced by grinding the surface of the tile product to remove anywhere from .002 to .010 of an inch (0.05 to 0.25 mm).

While grinding the surface of the product is desirable in order to highlight the dot design it is not necessary for securing the unsmeared pattern on the surface of the tile.

By the term "marble particles" is meant in general any of a family of stone particles having a Mohs hardness in the range of 2.5 to 3.5.

While marble particles are preferred, it is also possible to use a plastic particle in the invention provided that the plastic particle is sufficiently hard that it will not streak during coloring. A hard plastic resin that may be used in lieu of the marble particles is for example a phenolformaldehyde resin such as sold under the trademark "Bakelite" which has a "Shore D" hardness of approximately 82.

The preferred particle material to be used is a marble particle that has a size such that it will pass through a U. S. Standard 10 mesh screen, but will not pass through a U. S. Standard 60 mesh screen. This is referred to as a particle size of 10 to 60 mesh. Particles of this size range may be obtained by appropriate grinding.

The particles may be uniformly spread through the whole sheet and/or they may be concentrated primarily on or in the surface layer of the sheet. They may be concentrated on the surface layer either by being made as a separate layer to be added to a base layer or as a layer which is sprinkled on the top of the hot sheet after it is first milled and then subsequently passed through additional calendering steps which tend to embed the particles in the upper surface area of the sheet product.

Claims (10)

1. A flat thermoplastic tile having a first coloration, at least one primary surface area of the tile having distributed therein a plurality of particles of 10 to 60 U. S. Standard Mesh size, the particles being of a second coloration, different from the first, and being unoriented and free from smearing.

2. The tile of claim 1 wherein the particles are distributed throughout the tile product.

3. The tile of claim 1 wherein the particles are distributed predominantly in the area adjacent the primary surface.

4. The tile of any one of claims 1 to 3 wherein the particles are of a Mohs hardness in the range of 2.5 to 3.5.

5. The tile of any one of claims 1 to 4 wherein the particles are marble chips.

6. The tile of any one of claims 1 to 3 wherein the particles are a plastic resin having a hardness of aproximately Shore D 82.

7. An improved composition tile comprising a filled plastic mass of a primary coloration having a thermoplastic binder system and a filler, said tile being in a flat sheet shape with one surface thereof being a wear surface area, the improvement comprising: a plurality of particles of 10 to 60 mesh size distributed in the surface area of the tile, said particles being of a contrasting coloration to the plastic mass coloration and being of a nondirectional, unsmeared shape in the finished product.

8. A method for making an improved composition tile having a filled thermoplastic mass of a primary coloration, said mass being a thermoplastic binder system and a filler, the steps comprising: (a) mixing together the thermoplastic binder system and a filler in a mixer, (b) at some point prior to removing the mass of plastic material from the mixer, blending thereinto a mass of hard particles of material having a coloration different from the coloration of the thermoplastic mass, (c) dumping the plastic mass from the mixer onto a calendering means which will form the mass of material into a sheet form, and then forming the sheet into a plurality of square tile units wherein the hard particle means added to the plastic mass will appear as a dot pattern distributed across the surface of the tile product with the particles being of a contrasting coloration to the coloration of the plastic mass and the particles appearing as non-directional, unsmeared shapes in the surface area of the tile product.

9. A thermoplastic sheet having a first coloration, at least one surface area having distributed therein a plurality of particles of a second coloration different from the first, the particles being randomly oriented and free from smearing, the particles being of 10 to 60 U. S.

Standard Mesh size.

10. Any new or novel feature or combination of features herein before described.