GB2128898A - Surface covering material - Google Patents

Abstract

A decorative floor covering in tile form has a design printed on its upper surface. Particles are positioned on the upper surface of the tile with at least some of the particles being placed on the tile surface in register with the design printed on the tile surface. A cured wear layer overlies both the particles and the plastic base, whereby the wear layer surface in the areas containing particles and in the areas not containing particles will be of different gloss characteristics. The process requires the sprinkling of particles over an adhesive coated surface to retain the particles in registration with a printed design on the tile surface. <IMAGE>

Description

SPECIFICATION Surface covering material This invention relates to a surface covering material, especially a decorative plastic floortile and its method of manufacture.

It is known in the prior artto provide, where desirable, wear resistant layers. Commercial tile has been provided with a non-skid surface by heating individual pieces of ordinary vinyl tile and spraying the surface with carborundum grit. One then embeds the grit into the surface ofthetile, the grit particles imparting the non-skid characteristicto the tile. It has also been proposed to provide a slip resistant surface by providing the plastic flooring productwith a nubbly texture by incorporating particulate plastic material dispersed in the wear layer which is cured to form a textured wear layer. This latterfeature is disclosed in U.S. Patent No.4,196,243.

U.S. Patent No. 3,267,187 discloses a textured floor covering comprising a base layer, a plastic layer, and an overlying matrix containing particulate material embedded therein.

U.S. Patent No. 4,196,243 describes the application ofwear layers to floor coverings, particularly a non-skid photopolymerizable urethane layer.

U.S. Patent No. 3,928,706 discloses the use of hard quartz particles.

Patent Application Serial No. 2,093,370 disolves a non-skid decorative plastic floor covering composed of a decorative plastic base having a plurality of slip-resistant elements positioned on the base with a clear or translucent wear layer overlying the slipresistant elements and the exposed intervening base.

There has also been proposed a decorative plastic floor covering with a decorative plastic base having raised and depressed areas. A plurality of elements are positioned on the raised areas only and then thereover a cured clear of translucent wear layer overlies both the elements and the plastic base. The elements comprise particles embedded in a cured plastic matrixwhich is positioned on lyon the raised areas ofthe base. The particles are distributed on the plastic matrix in a substantially abutting relationship with a single layer of particles. The particles protrude above the matrix, but are below the uppermost level of the wear layer. The particles are rounded inorganic particles of quartz and have a Moh hardness greater than 4.The particles are distributed on the raised area of the base, such that none ofthe particles are greater than about 595 microns, with about 55% of the particles being about 149 to 296 microns in size. The wear layer is a cured urethane composition.

U.S. Patent No. 3,343,975 discloses the application of granules to a printed vinyl substrate but, in all cases, the granules are not of an aggregate composition but are instead of resinous composition.

U.S. Patent No. 4,126,727 discloses the concept of providing a resinous, polymer material with a pattern printed thereon. Awear layer is then bonded to the patterned sheet, and the wear layer contains mica chips or chips of similar material. The chips are embedded in a separate preformed sheet which is then laminated to the pattern layer.

U.S. Patent No.3,328,231 discloses the formation of a surface from a hardened cured composition of a polyester, or similar resin, and sand.

U.S. Patents Nos. 4,255,480 and 4,263,081 disclose an abrasive-resistant laminateformed by coating a printed paper base with mineral particles and then impregnating the paperwith a laminating resin.

U.S. Patents Nos. 3,121,642; 3,135,643; 3,343,975; 3,523,849; 3,562,051; 3,607,539; 3,660,187; 3,661,673; 3,798,111; 4,212,691 and 4,278,483 are other patents which disclose other methods for forming wear- or abrasive-resistant surfaces and are indicative of the art.

According to the present invention, a surface covering material, especially a decorative plastic floor covering in tile form, comprises a decorative plastic base having a design printed on its upper surface.

Particles positioned on the upper surface of the tile are so positioned that at least some of the particles are placed in registration with the design printed on the tile surface. It will be understood that according to the present invention the particles may be applied to the surface covering in registry with some part or parts of the decorative pattern thereon readily visible to the eye, rather than solely in registry with an adhesive layer present onlyto holdtheparticlesthemselves.A cured clear ortranslucent wear layer overlies both the particles and the plastic base whereby the wear layer surface in the areas containing particles and in the areas not containing particles will be of different gloss characterisitics.The particles are preferably rounded inorganic particles.The inorganic particles useful in the practice of the invention to form the wear surface are preferably substantially insoluble in water and have a Moh hardness of at least 4 and preferably at least 7. They preferably have a particle size distribution wherein none of the particles are greaterthan about 595 microns and about 55% of the particles are between 149 and 296 microns in size. The particles are desirably unaffected by subsequent processing, so thatthey retain their identity in the final product. If they are organic, they are desirably not thermoplastic.

The particles are preferably sand, having a Moh hardness of about7 and a particle size distribution such that none are greaterthan about 595 microns and about 55% ofthe particles are between 149 and 296 microns.

A method is provided for making the product. First a design is printed on the upper surface of, for example, a tile. An adhesive coating is placed in registration to selected portions ofthe printed tile design. Sand particles are sprinkled over the adhesive coated tile surface. One then removes the excess sand particles not retained on thetilesurface bythe adhesive. The sand particles are consolidated into the adhesive and then the adhesive may be cured. There is then applied a wear coating over the top of both areas covered by the sand particles and areas not covered by the sand particles and this wear layer is cured. There is then provided a wear surface with areas of differential gloss where the sand particles exist and where the sand particles do not exist.

The invention provides a surface covering, especiallyaflooring product which is primarily a durable low-maintenancefloortile but which, more importantly, possesses unique visual characteristics. The procedure outlined below results in a particularly good technique for achieving unexpectedly realistic ceramic-like images on vinyl composition flooring materials. Decorative ceramic tile images in vinyl floors are typically simulated by rotogravure printing a substrate, overcoating with wear layer material of either vinyl or urethane compositions, and embossing to provide textures and surface relief. Although these flooring materials can be very appealing and attractive, they have the traditional wear properties of vinyl floor and tend to be visually flat and two-dimensional.

Further, they do not possess the many visual characteristics, both subtle and otherwise, generally associate with real ceramictile.

The invention herein provides a structure and a process for achieving many of the characteristics of ceramictile while, at the same time, offering outstanding performance properties. The basic process involves the application of particulate matter of specific size and color onto a decorative flooring substrate followed by the application of a UV curable wear layer.

A numberofvariations have been carried out and are described briefly below. The particulate matter can be a variety of materials. Silica, either clear or colored, is preferred, although other materials, for example garnet and aluminium oxide, can be and have been experimented with. A preferred decorative floor substrate is a printed vinyl composition and the decoration is carried out preferably by transfer printing with a rotogravure-printed transfer paper or by flexographic printing directed onto the substrate.

The particulate matter is positioned in register with the printedside in one of several ways.

For a substrate that has been transfer printed or flexographically printed, or decorated by some other printing technique, the UV curable adhesive material is applied in register with the printed design. The adhesive can bye applied by,forexample,screen printing orflexographic printing. The selected particulate is then applied to the printed substrate with its adhesive byflooding the entire surface and removing that which does not stick to the adhesive. The quantity of particulate material that adheres to the tile can be controlled bythe amount of adhesive that is applied.

The retained particulate is then smoothed and consolidated by passing the material between a pai r of rolls.

The adhesive is then cured.

An overcoat of UV-curable material (wear layer) is then applied by roll coating and/orcurtain coating to provide a smooth functional surface. Multiple passes through a process are possible and desirable. A variety of colors and/or particulate sizes can be applied to the printed substrate to provide a broad capability for unique designs.

It is also possible to applythe adhesive and decorate the substrate simultaneously. For example, a smooth or embossed undecorated su rface can beflexographi- cally printed with the UV curable pigmented adhesive which serves both to decorate and hold the particulate materials. Another option is to uniformly apply a particulate material overthe entire surface of a decorated sustrate followed by a second particulate application on top of the previously applied layer in register with a design. Such a structure provides even better wear characteristics than those with only a partially covered surface.

One of the advantages ofthe invention herein is that a surface relief or an embossing-in-register effect with a decoration can be accomplished. The variable surface textures and the variable surface glosses are both controllable. The product can be provided with good wearing properties and many visual effects are possible.

One construction according to the invention will now be described, by way of example only, in greater detail with reference to the accompanying drawing, of which the sole figure is an enlarged cross-section of a tile.

Referring now to the figure, a decorative plastic floor covering tile 2 comprises a plastic base 4which is composed of a conventional vinyl or vinyl composition tile material. Normally, the tile product is 9" x 9" (0.23 x 0.23 m) square and has a nominal thickness of 0.096" (2.4 mm). A design 6 is applied to the upper surface of the tile. Particles 8 are then placed on the uppersurfaceofthetile, and at least some ofthe particles are placed on the tile surface in registration with the design printed on the tle surface. In the structure shown in the drawing,the design 6 is composed of two components 10 and athird component 12 which is different in design/colorfrom the two components 10. The particles are applied in register with the component 12 ofthe design.Over the top surface ofthetile covering both the areas containing particles and the areas not containing particles, there is provided is clear ortranslucentwear layer 14. It is observed thatthose areas containing particles have a gloss characteristic differing from that of those areas which do not contain particles. Consequently, that meansthatthe area above the printed design component 10 will have a different gloss characteristics than the area above printed design component 12.

The particles 8which are applied to thetopsurface ofthetile are rounded particles of sand which have a Moh hardness of about 7 and a particle size distribution such that none are greaterthan about 595 microns, and about 55 percent of the particles are between 149 and 296 microns. The particles are commercially available as the "Special Bond" grade of sand which is offered by the Ottawa Silica Co. of Ottawa, Illinois. The sand is 99.8% SiO2 and may be a natural color, or the sand may be colored to provide a colored effect to the end product.

Typical sieve analysis of the inorganic silica particles is as follows: U.S. Sieve Size Percent (mesh) Size of Openings Retained Screen 30 595 microns - Screen 40 420 microns 3.0 Screen 50 296 microns 34.0 Screen 70 210 microns 39.0 Screen 100 149 microns 18.0 Screen 140 105 microns 5.0 Screen Pan 1.0 The adhesive coating used is as follows. To form the polyester adhesive, the following ingredients were charged to a liter, fi-necked flask condenser (upright) with still head and total condenser above. The flask was further equipped with mantle, stirrer, thermometer, temperature controls and gas inlet tu be. The ingredients were heated gradually with stirring to 220 + 5"C under nitrogen and held at this temperature until the acid numberfell below 1.5 + .5.

The nitrogen flow was gradually increased after about 70 percent of the theoretical water was obtained to about 700 ml per minute to help remove the water of esterification and drive the reversible equilibrium reaction to completion.

Ingredients Parts by Weight 1,6-Hexanediol 363.52 Neopentyl Glycol 661.25 Cyclohexanediomethanol 914.13 PhthalicAnhydride 563.81 Dibutyltin bis Lauryl Mercaptide Catalyst 2.48 IsophthalicAcid 1476.24 SiliconeAntifoam (Foamkill8R) 0.0566 Toluene 650.00 Acrylation of the polyester is carried out by charging 1.2 equivalents of acrylic acid to an appropriately sized 4-necked flask containing the polyestersolvent mixture. Sulfuric acid (0.24 parts per hundred parts resin) is added and the mixture held at reflux with a Barrett trap used to remove the water and return the solvent.

The batch temperature is held at 95 to 1 1 OOC. The reaction was terminated when between 90 and 98 percent of the theoretical waterwas obtained by cooling to 90"C and adding 1.3 equivalents of magnesium oxide dispersed in 100 parts by weight isodecyl acrylate with an additional 600 parts by weight of isodecyl acrylate also added. The flask ways then evacuated to 40 to 50 mm of mercury to remove solvent.Addition with agitation of 73.14 parts by weight 1,6-hexanediol diacrylate, 104.5 parts by weight acrylic acid, 100 parts by weight isodecyl acrylate, 104.5 parts by weight benzophenone and 62.7 parts by weight catalyst 2,2 - dimethoxy - 2 - phenylacetophenone (Irgacure 651) completes the curable adhesive preparation. This adhesive 9 is printed on the design 6 in registration with components ofthe design, and contains particles 8, preferably rounded inorganic particles.

To preparethe UV curable coating 14, the following reactants were charged into a reaction vellel: Ingredients Parts by Weight Polyesterpolyol* 36.15 2-Ethylexhylacrylate 13.33 1,6-Hexanediol diacrylate 9.07 *Reaction product of 34.62 parts by weight adipic acid, 13.12 parts by weight isophthalic acid, 48.76 parts byweight 1,6-hexanediol and 3.48 parts by weight glycerine.

23.10 parts by weight of 4,4' - diisocyanato dicyclohexylmethane and 0.08 parts by weight of dibuty tin dilaurate catalyst were then added and the mixture reacted at 45oC to 50"C. Afterthe reaction has proceeded for approximately 45 minutes, 8.67 parts byweightof2 - hydroxyethyl acrylatewas added and heating and stirring ofthe reaction mixture continued for two hours at which point the isocyanate functionality is constant.

To this reaction product arethen added 1.81 parts by weight benzophenone, 0.90 parts by weight 2,2 dimethoxy - 2 - phenylacetophenone, 6.78 parts by weight paracresol antioxidant and 0.09 parts by weightglycolpolysiloxane (DC-1 93). This coating could be used also as the adhesive coating.

The process for carrying out the manufacture of the above tile productrequiresfirstthe preparation of a conventional tile base. Also, there is prepared a transfer sheet containing a printed design thereon which it is desired to transfer to the the tile base. By an appropriate transfer printing operation which is conventional in the art, the transfer paper is placed up against the top surface of the tile base and through heat and pressure, the image from thetransfer sheet is transferred to the tile base.The tile base is now fed pasta printing unit such as a conventional direct flexographic printer and an adhesive coating is applied in register with the tile base design.This adhesive coating is only applied to select areas ofthe tile product and these areas that are printed are in register with the design printed on the tile base, though it would be possible, as described above, to overall print with an adhesive to putafirst layer of particles on and then, subsequently,followwith a second adhesive coating which would be in coordination with the tile design to then only partially cover the total tile surface with a second particulate material.

After the adhesive has been placed in register with the design onthetile, onethen cascades or sprinkles an excess of a mixture of clearer or artificially colored sand particles onto the surface ofthe tile base with its uncured adhesive layer. This uncured adhesive layer is the previously described polyestercurableadhe- sive. These sand particles will adhere to the adhesive without special treatment. The excess sand is removed with air jets and then, through a roll pressing operation, the sand particles areconsolidated into the adhesive. The tile is then conveyed under a conventional UV light sou rce and exposed to an amou nt or radiation sufficient to partially cure or completely cure the UV light adhesive and hold the particles in place. The product now has adhered to its surface an adhesive which is advantageously applied at the rate of 1.0 to 3.5 grams of material per square foot (about 11 ot 38 9 rams per square meter) of tile surface covered. This is then provided with a layer of particulate material which is applied atthe rate of about 15 grams persquarefoot(about 160 grams per square meter) covered and which is of a thickness in the range of 10 milsto 15 mils (0.25 to 0.38 mm).

Thewearcoatis now applied tothetile product at two layers. The wear coat is the previously described UV curable coating. It is first applied using a conventional forward roll coater that applies the first coat layerat about 130 F (53 C) with about 10 grams per square foot (about 108 grams per square meter) application rate. This coating fills in the space around the laid up sand and is done with a minimum of large bubbles being formed in the coating. A second layer ofthe same coating material is then applied atthe rate of about 10 grams persquarefoot (about 108 grams per square meter) using conventional curtain coating techniques. Both layers are then cured using UV light Typical of the energy dosage that could be used atthis point is a treatment of UV light at 4.5 joules UV energy. There is now provided a tile product which is unique from the point ofviewthat those areas with the sand particles are of a different gloss from those areas without sand particles.

Itwill be seen that, in the preferred product according to the invention, the particles lie on parts of the design that are at the same level as the remainder ofthe design, apartfrom the thickness of any adhesive still below the particles afterthe consolidation step.

Claims (9)

1. A decorative surface covering a decorative plastic base having on the uppersurface thereof a design printed thereon, particles positioned on the upper surface of the tile with at least some of the particles placed on the tile surface in registration with the design printed on the tile surface, a cured clear or translucent wear layer overlying both the particles and the plastic base whereby said surface covering in the areas containing particles and the areas not containing particles will be of different gloss characteristics.

2. A covering as claimed in claim 1, wherein the particles are inorganic particles.

3. A covering as claimed in claim 2, wherein the particles are rounded particles of sand having a Moh hardness of a bout 7 and a particle size distribution such that none are greaterthan about 595 microns, and about 55% ofthe particles are between 149 and 296 microns.

4. A covering as claimed in any one of claims 1 to 3, wherein the surface covering is a plastic floor covering.

5. A covering as claimed in any one of claims 1 to 4, wherein the covering is in tile form.

6. A covering as claimed in any one of claims 1 to 5, wherein the parts ofthe design carrying particles are atthe same level as those not carrying particles.

7. A covering as claimed in any one of claims 1 to 6, wherein the wear layer is of a greaterthickness overthe parts ofthe design free from particles than on the particle-covered parts.

8. A decorative surface covering, substantially as described with reference to and as illustrated by the accompanying drawings.

9. A method of making a tile product comprising the steps of printing a design ontheuppersurfaces thereof, providing an adhesive coating in registerto selected portions ofthe printed tile design, sprinkling sand particles overthe adhesive coated tile surface, removing excess sand particles not retained on the tile surface bythe adhesive, consolidating the sand particles into the adhesive, applying a wear coating over both the areas covered by the sand particles and the areas not covered bythe sand particles, and finally curing said wear surface to provide areas of differential gloss wherethe sand particles exist and where the sand particles do not exist.