BACKGROUND OF THE INVENTION Carpet and carpet tile have long been adhesively bonded to floors in some installations and, in some instances, to other materials that are, in turn, bonded to the floor.

A number of approaches have been utilized for temporarily and permanently adhesively bonding carpet and carpet tile to the floor on which it is used. Among those approaches are the application of adhesive to the floor surface before positioning the carpet product on the floor surface, the application of adhesive to the underside of the carpet product before positioning it on the floor surface, and the interposition of an adhesive-carrying layer between the underside of the carpet product and the floor surface, such as the grid-like frame bearing pressure sensitive adhesive described in U.S. Patent No. 4,234,649 to Ward. The application of pressure sensitive adhesive to the underside of the carpet product presents a number of advantages including making installation easier by avoiding the need to apply adhesive to the floor. One of the best approaches involves application of pressure sensitive adhesive to the underside of carpet products during the manufacturing process so that no adhesive application is necessary during installation.

The principal drawback associated with the application of pressure sensitive adhesive during manufacture is the need to keep the adhesive layer protected and clean so that the adhesive sticks only to desired materials. This is normally accomplished by the application to the adhesive layer, during manufacture, of a protective film or "release" layer that can be removed immediately prior to the installation of the carpet product and then discarded. Because they are thin, relatively inexpensive and widely available, polyethylene films are widely used in such applications, as well as in numerous other instances where pressure sensitive adhesive is used. The same

considerations have resulted in use of other films and of coated and other paper release layers, such as "kraft" paper.

Film and paper release layers are disclosed, for instance, in U.S. Patent No.

4,242,389 to Howell, U.S. Patent No. 3,010,859 to Stephens et al. and U.S. Patent No.

3,014,829 to Curtin.

Substantial problems are associated with the use of polyethylene and other film or kraft paper as a release layer. During the course of installation of carpet or carpet tile, the release layer must be removed and handled and ultimately disposed of.

Polyethylene and other films and kraft paper are bulky after removal because they will not easily compress into a small volume of space. As a result, they are constantly in the installer's way during installation and present significant ultimate disposal problems.

There are also challenges associated with recycling such materials. Another significant feature of such prior art release films and layers is that they must be removed during the course of installation; the carpet products cannot be installed with the release layer left in place.

SUMMARY OF THE NVENTION The present invention is a carpet or carpet tile product having a yarn pile or other face layer, intermediate backing structure below the face material, a pressure sensitive adhesive layer, and a layer of non-woven material adhered to the pressure sensitive adhesive. This non-woven material typically acts as a release layer and is advantageous as such because it can be wadded, folded or otherwise compressed into a very small volume. This avoids handling problems associated with dealing with conventional release layers during installation, makes it easy to transport the removed release layer away from installation sites and makes it easy to dispose of or recycle the release layer. Significantly, use of the non-woven layer of the present invention gives the carpet product a supple "hand," thereby facilitating installation.

Furthermore, the non-woven "release" layer of the present invention can be left in place as the bottom-most layer of the carpet product where it is desired to install the product without use of adhesive or is desirable to utilize separate adhesive applied at

the time of installation to the bottom-most surface of the carpet product or, more typically, to the floor.

While a variety of materials can be used as the release layer of present invention, a material found to be particularly appropriate for this application is spunbonded non-woven polypropylene fabric. The release layer of the present invention normally will be applied as a single piece of fabric on carpet tile. Similarly, the layer can also be applied in a single piece spanning the width of broadloom or roll goods, whether six feet wide, twelve feet wide or other widths. For ease of handling and removal during installation, however, it may be preferable to apply the release layer to roll goods in less than full width, such as in thirty (30) inch widths. A multi-piece release layer may also be desirable on carpet tiles to facilitate removal.

BRIEF DESCRIPTION OF THE FIGURE The figure is a perspective view showing the top and one turned-up comer of the carpet or carpet tile of the present invention using the non-woven fabric release layer of the present invention.

DETAILED DESCRIPTION OF THE FIGURE The figure illustrates a piece of carpet or carpet tile 10 of the present invention.

Carpet 10 includes an upper or "face" structure made of nylon, wool or other natural or synthetic yarn pile or other material 12 that is bonded, fused, stitched, needled, needle punched, tufted woven or otherwise attached to backing structure 14.

Backing structure 14 may include primary and secondary backing and may utilize stiffing and stabilizing layers of fiberglass or other materials and may incorporate a wide variety of additional materials and components, including, among others, polyvinyl chloride, polypropylene, polyurethane, bitumen, fillers, fire retardants and smoke suppressants.

A layer of pressure sensitive adhesive 16 is applied to the underside of backing structure 14. Usable adhesives include, among others, Rohm and Haas Rhoplex N-619, a thermoplastic acrylic emulsion adhesive. As will be understood by those skilled in

the art, numerous other solvent-based and latex emulsion adhesives can be used that will provide acceptable adhesion between backing 14 and the floor on which the carpet 10 is to be installed.

Release layer 18, shown partially peeled away from adhesive 16 in the figure, is applied to the underside of pressure sensitive adhesive 16. While layer 18 of the present invention is generally referred to here as a "release layer," it should be understood that layer 18 is not in all installations removed from the pressure sensitive adhesive 16 of carpet product 10, in which instances it does not actually serve a "release" function.

In the illustrated embodiment of the present invention, the material for release layer 18 is spunbonded non-woven polypropylene fabric having a weight of approximately four ounces per square yard, which may be white in color. Lighter and heavier weights of release layer 18 can also be used depending on the application, including weights as low as 0.75 ounces per square yard, although weights less than about two ounces per square yard may be susceptible to tearing when the release layer is removed. Heavier weights also may be used. Other colors than white, including black in particular, may also, of course, be used.

Spunbonded non-woven polypropylene fabric useable for the release layer of present invention is available from Poly-Bond Incorporated, 1020 Shenandoah Village Drive, Waynesboro, Virginia 22980. Spunbonded non-woven polypropylene fabric provided by Poly-Bond Incorporated is available with an anti-static material added.

Other fibrous fabrics can also be utilized as release layer 18 in accordance with the present invention, provided that they exhibit an acceptable balance of desirable characteristics similar to those exhibited by the above-described spunbonded non- woven polypropylene fabric. Those characteristics include economy, ease of release from adhesive 16 (without, for instance, unduly tearing or pulling apart and without leaving fibers adhered to adhesive 16), ease of handling after removal from adhesive 16, recyclability and agreeable "hand." Accordingly, fabrics formed not only from polypropylene but also from other synthetic and natural fibers and blends of fibers by spunbonding, needling, knitting, weaving and other techniques may be usable as release layer 18.

In order to install carpet 10 in a typical glue-down installation, release layer 18 is removed and carpet 10 is positioned in the desired location with pressure sensitive adhesive 16 contacting the underlying floor structure.

Alternatively, in some installations it maybe desirable to leave release layer 18 in place and "loose lay" carpet 10 on the floor without adhesive contact with the floor or by interposing adhesive between the floor and release layer 18.