US3579410A - Parquet flooring block and method of making same - Google Patents

Abstract

A PREFINISHED UNIT OF PARQUET BOORING IMPREGNATED THROUGHOUT THE TOTAL THICKNESS THEREOF WITH A MONOMER THAT IS POLYMERIZED TO A PLASTIC MATERIAL HAVING A HIGH RESISTANCE TO ABRASIVE WEAR. THE SEPARATE SLATS, WHICH MAY BE QUITE THIN, ARE ASSEMBLED IN BLOCKS PRIOR TO CONVERSION FROM ORDINARY WOOD TO A WOOD-PLASTIC COMPOSITE, AND THE BLOCK MAY THEREAFTER BE PREFINISH BEFORE SHIPPING AND EASILY LAID ON A SUB-FLOOR WITHOUT THE NEED FOR ONSITE FLOOR FINISHING CREWS.

Description

y 18, 1971 1.. G. BARRETT 3,579,410

PARQUET FLOORING BLOCK AND METHOD OF MAKING SAME 2 Sheets-Sheet 1 Filed Sept. 6 1967 FIG. 3

INVENTOR LAWRENCE G. BARRETT M, M, MM, Arman M46;

ATTORNEYS y 1971 L. G. BARRETT PARQUET FLOORING BLOCK AND METHOD OF MAKING SAME 2 Sheets-Sheet 2 Filed Sept. 6, 1967 FIG? INVENTOR BARRETT BY dwkzr a WL-r4,-

ATTORNEYS United States Patent Q 3,579,410 PARQUET FLOORING BLOCK AND METHOD OF MAKING SAME Lawrence G. Barrett, Lynchburg, Va., assignor to The American Novawood Corporation, Lynchburg, Va. Filed Sept. 6, 1967, Ser. No. 665,860 Int. Cl. E04f 13/10, 13/18, 15/16 U.S. Cl. 161-38 6 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to a unique flooring block which is made from a wood-plastic composite and either finished after installation or prefinished at the factory.

Parquet flooring units have long been used in the flooring industry. Heretofore, it has been the practice of the industry to produce and to supply unfinished flooring units bonded by a backing, such as paper, on one or both sides. These unfinished units are conventionally laid on a subfloor in a mastic compound, leveled, and finished in a manner typical of other types of wood flooring after removal of any upper surface covering. Certain deficiencies in the laying of unfinished flooring are readily apparent upon consideration of the cost and often the difficulty in obtaining the services of skilled labor in performing the finishing of the fioor in situ, floors conventionally requiring extensive sanding and multiple coats of a protective varnish or the like. Paint and other finishing materials, sand paper, sanding machines, etc., must be transported to the site and there maintained in sufiicient supply and in operating condition in anticipation of the progress actually made in laying of the floor. The unfinished flooring units, in addition, are subjected to a number of hazards including substantial dimensional changes when exposed to changes in moisture during storage and handling.

To eliminate a number of the foregoing disadvantages, the production of prefinished flooring panels has been adopted. The desired finish is placed on these flooring units under the controlled conditions of the manufacturing plant and such flooring units have a more uniform and a higher quality appearance. These prefinished units, while less responsive to dimensional changes due to moisture during shipping and storage because of the finish on their upper surface, are still subjected to some dimensional instability due to the absorption of moisture through the unprotected ends and the underside of the unit.

By the use of a wood-plastic composite, many of the foregoing disadvantages are eliminated. The wood-plastic composite used in accordance with the present invention is basically wood that has been impregnated with a monomer that is subsequently polymerized thereby providing several improved properties to the wood. The surfaces 3,579,410 Patented May 18, 1971 are relatively impervious to moisture which reduces undesired dimensional changes and produces improved stain resistance which is important where foods, pet excretion and the like are in evidence. Any staining which occurs from strong solvents is readily removed by use of household cleansers or steel wool.

Among the other important advantages is the fact that the polymers used may have greatly increased resistance to wear and abrasion. Even if the surface wears down, as would occur in regions of heavy traffic, the finish may be made uniform throughout the thickness of the flooring unit and the desirable surface appearance properties are retained without the need for frequent refinishing.

Because of the added cost necessary to convert wood into a wood-plastic composite, it is important to minimize the dimensional thickness of the flooring block to be competitive with conventional flooring. Use of thicknesses down to about 4; inch introduced certain problems of processing and handling of the flooring.

It is therefore the main object of this invention to provide a novel wood-plastic composite flooring block or unit which has superior wear-resistant properties and which may require no paint or lacquers in the finishing thereof, but which can be finished by the sole step of polishing the exposed surface.

Another object is to provide a novel parquet flooring block or unit made from slats of a wood-plastic composite which may be in situ leveled to provide an improved appearance of the completed floor.

Yet another Object of the present invention is to provide a parquet flooring unit made from slats of a woodplastic composite where the slats are held together during the conversion of the wood by unuique techniques, such as by use of splines, backing members and/or frames which may or may not be removed after the wood is converted.

A further object is to provide a novel process for making the wood-plastic composite flooring block wherein the slats are assembled together before conversion and the polymer upon conversion aids in holding the individual slats together as a flooring block. Where a backing mem her is used, it may, if porous, be quite flimsy and weak because after impregnation and conversion, the polymer greatly adds to its strength and to the adhesive force holding the backing member to the flooring block. The backing member may, if desired, be allowed to extend beyond the periphery of the flooring unit to thus aid in holding together adjacent flooring blocks when placed on a sub-floor in a suitable adhesive or mastic.

These and other objects and advantages of the present invention will become more fully apparent from the appended claims, and from the following description when read in conjunction with the drawings, wherein:

FIG. 1 is a perspective view of the novel parquet flooring unit of the present invention;

FIG. 2 is an enlarged fragmentary bottom view of one corner of the flooring unit of FIG. 1 illustrating the use of a loosely woven backing member;

FIG. 3 is an end view illustrating the ability of the flooring units of FIG. 1 to conform to irregularities in the sub-floor;

FIG. 4 is a bottom view of a flooring unit having a porous fiber backing for holding the slats together in a flooring block;

FIG. 5 is a pictorial view of a flooring unit wherein the slats are held together by a spline;

FIG. 6 is a view of a flooring unit wherein the slats are held together during the conversion process by a frame that is adapted to be removed after the conversion process is completed; and

FIG. 7 is a view partially in section showing a multiple ply flooring block having one or more veneer layers of wood-plastic composite.

Referring now to the drawings, the novel parquet flooring unit 10 of the present invention comprises a plurality of squares 12 each made up of an equal number of elongated slats 14 assembled in a side-by-side relationship. The slats 14 are substantially uniform in size. Conventionally, such squares have side edges that range from between approximately /2 to 2 /2 inches, and the thicknesses usually exceed /2 inch. However, the present invention is characterized in part by the fact that the thickness may be as little as inch, and a /8 inch thickness is regarded to be a maximum that would ever be needed. The squares 12 may be conveniently arranged so that the grain of all of the slats 14 of each square 12 extends longitudinally in the same direction and the adjacent squares 12 oriented at 90 to each other to present an alternating or checkerboard configuration. Obviously, other shapes and grain patterns may be adopted, as the particular orientation of the grain pattern is no part of the present invention.

As shown in FIG. 2, the individual slats 14 are assembled on a loosely woven backing member 16 which may conveniently be thread, or a strand of a suitable material such as cotton, or a first thermoplastic resin that is applied to the slats 14 with another or the same thermoplastic resin. It will be appreciated that the backing member as illustrated in FIG. 2 comprises strands formed in a Woven pattern with the spacing between strands being much larger than the thickness of the strands. The choice of material for the backing member 16 is dictated in part by the wood conversion process as will be hereinafter explained and must after conversion possess sufiicient strength and be adequately secured to the block to hold the slats 14 together during their further handling. If the blocks are prefinished at the factory, then the backing member must maintain the slats together while the flooring block is processed through a subsequent sanding and pumicing operation.

A chamfer 18 may be cut along the upper periphery of the flooring unit 10 to reduce slight variations in the height of adjacent flooring units 10 due to irregularities in the sub-flooring 20. Some of the need for leveling may be eliminated in this manner.

Flooring units 10 of the character described may be readily and conventionally installed in the manner of asphalt or plastic tiles by applying a suitable mastic or the like on the sub-floor 20 to a predetermined thickness and laying the flooring units 10 in the mastic in an abutting edge-to-edge relationship. Due to the looseness of the weave of the backing member 16, a large portion of the underside 22 of the flooring units 10 are exposed and a bond may be achieved directly between the sub-flooring 20 and the individual slats 14 which comprise the flooring unit 10.

As shown in FIG. 3, the flooring units 10 laid on an uneven sub-floor 20 will accommodate themselves to the contours of the sub-floor by reason of the lack of any connection between slats 14 other than the flexible backing member 16. The short length and orientation of the individual slats also contribute to the ability of the flooring unit 10 to conform to the contours of the sub-floor 20.

The vastly improved abrasive wear characteristics of the flooring units 10 of the present invention are achieved through the conversion of the wood to a wood-plastic composite. The conversion process is disclosed and claimed in my copending US. application, Ser. No. 678,584, filed Oct. 27, 1967, for Method and Apparatus 4 for Converting Wood to a Wood-Plastic Composite, which is hereby incorporated by reference.

In the process there disclosed, the individual slats 14 are cut to size from a suitable wood having the grain characteristics desired to be displayed in the finished floor. The slats 14 are then assembled on the backing member 16 in the desired configuration and held in place by a suitable adhesive.

The choice of a material for the backing member 16 is dependent on a number of factors including the choice of the monomer with which the slats 14 are to be impregnated in the conversion process. The choice of the monomer is of course determined by the characteristics desired in the converted article. A monomer that has certain desirable properties is methylmethacrylate; polymerization may be effected by exposure to gamma radiation. If the slats are to be impregnated with the monomer and then converted by the polymerization thereof within the wood after assembly on the backing member, the backing member 16 is advantageously relatively insoluble in the monomer.

Conversion of the wooden slats to a wood-plastic composite results in vastly improved abrasive wear characteristics which extend to the depth of the monomer penetration. Where the penetration extends through the total thickness of the slats, the wear-resistant and desirable appearance properties extend completely through the thickness of the slat. Thus, as the surface wears down, the new surface that is exposed has the same properties as the original upper slat surface, and refinishing as is customarily required on wooden flooring is not required. Moreover, the rate of wear is reduced so that the actual thickness of the slats can be as little as Ms inch for many applications, and even in the heaviest traffic areas, a thickness exceeding /8 inch is not required.

One important aspect of the present invention resides in the assembling of the wooden slats prior to conversion of the wood into a wood-plastic composite. Several advantages in the finished fiooring unit or block result from having secured together a number of slats into an integral unit prior to the point in time when the slats are loaded with the monomer which is, of course, prior to the conversion step. Several techniques may be employed, and that shown in FIG. 1 involves the use of a backing member 16, which has been described above.

An important consideration in the conversion process with the slats already assembled in blocks is the swelling of the wood. By way of example, red oak having a 5% equilibrium moisture content will swell very little along the grain but each quarter sawn slat 14 of the flooring unit 10 having overall dimensions of 11 x 11 inches will increase approximately .008 in width. It is thus necessary to compensate by reducing the dimensions of the slats 14 an appropriate amount prior to conversion. This may be accomplished by cutting the strips 14 undersize or by controlled drying to shrink the slats to a size which will swell to the dimension desired upon impregnation.

After conversion of the flooring unit 10, i.e., the backing member 16 and assembled slats 14, the flooring unit 10 may be finished simply by sanding and polishing the upper surface thereof. This may be conveniently accomplished in the manner suitable for sanding conventional prefinished parquet flooring through the use of multiple drum or belt sanders (not shown) having successive stages utilizing sandpaper having a progressively finer grit. The final polishing of the upper surface of the flooring units may also be accomplished in a conventional manner through the use of pumice or other fine grit abrasive substance.

The wood of the flooring unit 10 that is converted to a wood-plastic composite has a finish that is coextensive with the depth of conversion. It will be appreciated, however, that the wood is advantageously impregnated with the monomer throughout the total thickness of the slats 14. Normal abrasive wear will reduce the thickness of the flooring units 10, but will not appreciably detract from the quality and lustre of the surface thereof. The black stains commonly found in parquet flooring, stains resulting from food or pet excrement, are easily removed. Significant marring may be eliminated by spot sanding or buffing the appropriate portion of the upper surface of the flooring units 10 with a mild abrasive such as pumice or the like. The upper surface may receive additional protection in the form of a conventionally applied coating of commercially available flooring wax.

Should unevenness of the sub-flooring result in a discontinuity between the upper surfaces of adjacent flooring units 10 to an extent that the chamfer 18 of the upper periphery thereof does not obviate the necessity for in situ leveling, the high spots may be easily spot sanded to accomplish leveling of the floor without fear of inability to match the appearance of other portions of the floor.

By the foregoing, it can be seen that the prefinished flooring units 10 may be quickly and easily installed to form a complete floor which is immediately ready for use after the leveling thereof. The elimination of the necessity for finishing the surface of the floor in situ or of attempting to match the factory applied finish of adjacent flooring units after spot leveling is a material advance in the art. In addition, the bonding of the individual slats 14 directly to the sub-floor 20 enhances the permanence of the floor.

Referring now to FIG. 4, a block of flooring 26 is il lustrated wherein the slats 28 are secured together by two strips 30 and 32 of a fibrous material that is porous to be absorptive of the monomer. Strips 30 and 32 may be initially applied to the bottom surfaces of slats 28 by any suitable adhesive. The entire block is then impregnated with the monomer which is also absorbed by strips 30 and 32. Upon conversion, the polymerization of the monomer increases the bonding strength of strips 30 and 32 to slats 28. Thus, it is not necessary that the backing members in the form of strips 30 and 32 completely cover the lower surface of slats 28 as in the case of the embodiment shown in FIG. 2, though in some applications this may be desirable.

Strips 30 and 32 may be a paperboard or felt and have relatively low strength before the conversion process, since after polymerization of the absorbed monomer, their rigidity and strength are substantially enhanced. Since the thickness of strips 30 and 32 is small, it is advantageous to have the marginal edges extend beyond the periphery of block 26 so that during installation of the floor, they will extend under adjacent blocks and thus reduce the tendency of the blocks to separate.

FIG. illustrates yet another technique by which the slats of a block may be held together. In FIG. 5, the slats 34 of the block are provided with a slot 36 along the ends. A spline or dowel 38 is provided in slot 36. By providing a similar construction at the opposite end, slats 34 may be held in a unitary block during the conversion process and thereafter handled without separatmg.

Referring now to FIG. 6, an arrangement is illustrated wherein slats 40, which form the flooring unit or block, are held together prior to loading with the monomer by a suitable frame or clamp which is removed before the flooring unit is placed into use. The clamp may be in the form of flexible metal strips which engage the outside edges of the slats 40, as illustrated in FIG. 6, and which extend above the Wearing surface of the flooring unit to thereby minimize interference when loading the slats with the monomer. If sufiicient monomer does not penetrate along joints 44 between adjacent slats to bond the slats together, a slight spacing may be provided between portions of the abutting slat edges to accommodate a thin layer of monomer which, when polymerized, serves to hold the slats together even after removal of the clamps 42. Clamps 42 may be removed at the factory before shipping and reused during the conversion process.

In some instances, it may be desirable to use a backing member which is very limber and incapable of holding the slats together in a satisfactory manner prior to conversion into the wood-plastic composite. The use of a frame or clamping arrangement, such as illustrated in FIG. 6, together with such a backing member which will absorb monomer and gain sufiicient rigidity during the polymerization process to serve as an efiective backing member, may be advantageous.

Referring now to FIG. 7, a flooring unit is illustrated which is laminated in construction. The upper layer 46 may be a face veneer having a thickness on the order of inch. The upper layer 46 is preferably impregnated throughout the total thickness thereof with a monomer that is later polymerized to a plastic material to provide high resistance to wear due to abrasion. The re maining layers may also be totally impregnated. Small grooves 48 may be provided to produce small sections which simulate a slat construction used in parquet flooring. The lower layer 50 serves as a backing member, and one or more cross-bands having their grain disposed at not less than 45 from the direction of the grain of the adjacent sheets may be provided as layer 52. All of the layers are joined together with a suitable adhesive. The total thickness of the laminated flooring unit is preferably between /s and inch, and each of the sheets of wood preferably is less than 1/ 16 inch thick.

The invention may be embodied in other specific forms without departing from the spirit of the invention or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

1. A method of providing parquet flooring of a woodplastic composite comprising the steps of:

(a) providing wood in the form of substantially uniformly dimensioned slats having initial dimensions less than a final size between about 3 inches and 12 inches in length, between about /2 inch and 2 /2 inches in width, and between about A; inch and inch in thickness;

(b) assembling the slats together to form a flooring unit having upper and lower surfaces and maintaining the assembled slats in an assembled unit with a backing member secured to a lower portion of each slat in the unit, the backing member comprising spaced strands, each of said strands extending across the intersection of at least two adjacent slats with the spacing between the strands being much larger than the thickness of the strands thereby to expose a substantial portion of the lower surface of the flooring unit for bonding directly to a subfloor;

(c) impregnating the assembled slats throughout the total thickness thereof with a liquid monomer to swell the slats to dimensions not less than and sub stantially equal to the dimensions of said final size;

(d) converting the impregnated slats to a wood-plastic composite by polymerizing the impregnated monomer; and

(e) bonding the exposed lower portion of a flooring unit directly to a subfloor.

2. The method according to claim 1 wherein the step of providing wood in the form of substantially uniformly dimensioned slats having initial dimensions less than the dimensions of the final size includes cutting the strips to the initial dimensions.

3. The method according to claim 1 wherein the step of providing wood in the form of substantially uniformly dimensioned slats having initial dimensions less than the dimensions of the final size includes the step of drying the slats under controlled conditions to shrink the slats to said initial dimensions.

4. The method of claim 1 wherein the spaced strands are provided in a Woven pattern.

5. The flooring assembly produced by the process of claim 1.

6. The flooring assembly produced by the process of claim 4.

References Cited UNITED STATES PATENTS 1,796,880 3/1931 Allen 52586 2,591,768 4/1952 Austin 117116X 2,835,936 5/1958 Elmendorf 16l--38 2,887,867 5/1959 Burchenal et a1 161-39X 3,077,417 2/1963 Kenaga 204159.12X

'8 4/1964 Tibbals 52586 6/1964 Sisko 1 61-37 10/1966 Dittmar 52390X 4/1968 Shook et a1. 16139X 12/1969 Waite 16138X 12/ 1969 Morgan et a1 117-116X FOREIGN PATENTS 1/ 1957 Australia 52384 7/1954 France 52390 JOHN T. GOOLKASIAN, Primary Examiner J. C. GIL, Assistant Examiner US. Cl. X.-R.

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