Coating processes – Coating remains adhesive or is intended to be made adhesive
Reexamination Certificate
2001-02-21
2003-02-18
Ahmad, Nasser (Department: 1772)
Coating processes
Coating remains adhesive or is intended to be made adhesive
C427S208000, C427S208400, C427S299000, C427S372200
Reexamination Certificate
active
06521289
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to carpet underlays and more particularly to an underlay for releasably adhering a carpet to a floor surface.
DESCRIPTION OF RELATED ART
Carpets are frequently used to enhance the appearance of rooms by placing them at selected locations. In such situations, it is desirable to provide an underlay beneath the underside of the carpet to prevent the carpet from slipping. Such underlays may take many forms, such as jute, sponge, latex, etc.
Contract carpet used in commercial installations is frequently adhered directly to the surface on which the carpet is placed. When carpets are used on areas where the carpet is cemented or adhered directly to the floor, different considerations come into play, particularly because of the possibility of the need for replacement. It is desirable that the carpet can be removed without leaving undesirable residue from the contact cement that also needs to be removed. Thus, the ability of the underlay to release from the surface, or from the underside of a carpet to provide undercarpet access, without leaving an appreciable amount of residue on the surface is an important consideration.
Contract carpet glued or cemented directly to a cement floor is known to have an undesired hollow sound when walked on. A proper underlay should avoid this problem. It is also desirable to fabricate the underlay in various thickness', thus providing additional cushioning and shock absorbency, enhancing the luxurious feel of the carpet underfoot.
Another problem of using contact cement or glue is the increased cost of installation. The cement is placed on the floor in the wet condition and installers need to wait until the cement begins to set. Care must be exercised not to step in wet areas. The increased time of installation translates to increased cost of installation.
In application of adhesive to a felt underlay, the adhesive is sprayed on the felt. The application of the adhesive is difficult to control, because felt disguises the amount of adhesive applied. As a result, the felt frequently absorbs too much adhesive, which works excessively into the porous surfaces of the untreated felt. The adhesive could then transfer onto the pile surface of the carpet and between the fibers of the carpet. Further, if the adhesive transferred to the carpet, a high powered solvent would have to be used to clean the adhesive from the underlying carpet. This could damage carpet coloration. Further, carpet adhesives have a tendency to clog spray heads, making application thereof difficult and unnecessarily costly, due to product line interruption.
SUMMARY OF THE INVENTION
With the foregoing in mind, it is a primary object of the present invention to provide an improved pressure sensitive, releasable, carpet underlay, which may be readily applied between the undersurface of a carpet and an underlying supporting floor surface, such that the underlay can then be firmly, but releasably, adhered to both the floor and the back of the carpet, and which does not suffer the aforenoted disadvantages of glue-down carpets.
Another object of the present invention is to provide an improved pressure sensitive, releasable, carpet underlay which is releasable from the underlying surface and the carpet with no appreciable residue transferred either to the underlying supporting surface or the carpet back.
Still another object of the present invention is to provide an improved pressure sensitive, releasable, carpet underlay which minimizes installation setup time.
Another object of the present invention is to provide an improved pressure sensitive, releasable, carpet underlay which enables carpet to be readily installed and which simplifies the installation procedure.
A further object of the present invention is to provide an improved carpet underlay which enables under-carpet access after installation.
A further object of the present invention is to provide an improved carpet underlay having both end-to-end and side-to-side effective gripping characteristics.
Another object of the present invention is to provide a carpet underlay that is effective in holding carpet to the floor and providing improved dimensional stability to the carpet.
These objects and their attendant advantages are achieved in accordance with the present invention, where a carpet underlay comprising a polypropylene felt substrate has a non-aggressive latex-acrylic adhesive coating applied thereto by a dipping method, which renders the substrate both water impervious, dimensionally stable and efficiently manufacturable.
In accordance with the invention, the underlying substrate of the underlay is manufactured from “needle-punched” polypropylene fibers arranged to form a non-woven felt fabric, to which an acrylic latex pressure sensitive adhesive is applied by a dipping process that coats the surfaces of the fibers and fills the interstices between the fibers. This renders the felt substrate water impervious. The acrylic adhesive is applied to the felt substrate in a dip and squeeze operation. The felt substrate is run through a trough of adhesive and then passed through an excess adhesive removal station, for example, squeegies, dams, or rollers which remove excessive adhesive from the felt into the trough. At least one release foil is applied to the adhesive coating prior to a curing stage.
In an alternative embodiment, a pre-coat dip and squeeze step is included prior to application of the pressure sensitive adhesive. The purpose of a pre-coat is to control the degree of absorption of the pressure sensitive adhesive into the felt. The pre-coat step is essentially the same as that followed in application of the pressure sensitive adhesive, with the pre-coat composition supplanting the adhesive. Following the application and fixing of the pre-coat, the pre-coated felt fabric is directed to the pressure sensitive adhesive dip and squeeze process.
Advantageously, the pressure sensitive adhesive is selected to prevent accidental delamination of the underlay from the carpet, by ensuring sufficient adhesion to all surfaces, including the backing of the carpet and its underlying carpet fibers and the bare floor. Consequently, the carpet and underlay will tend to remain affixed together and also to the underlying floor while in use. When it is desired to have access to the floor or replace the carpet, the carpet can be easily lifted in combination, or separately from the underlay, without leaving undesirable residue on the underlying floor surface.
When installing the product, if done at the installation-site, contact cement is not used and traditional set time is avoided. The underlay is chosen according to the size of the carpet and after a layer of release foil on one side is removed, the adhesive side of the underlay is pressed against the floor. The release foil on the other side is partially removed and the carpet is placed in rolled form over the exposed adhesive area. The remainder of the release foil is peeled back and the carpet rolled in place as the release foil is peeled away from the underlay.
Alternatively, the carpet is then placed over the underlay at the exact location where it is to be installed. The carpet is then folded back halfway upon itself, and half of the exposed release foil is peeled off to expose one-half of the adhesive face of the side which is to be applied to the underlying surface of the carpet. The carpet is thereafter folded back on the underlying surface and the process is repeated with the other half of the underlay. The other half of the release foil is removed and after the remainder of the release foil is removed, the folded portion of the underlay is then folded back on the underlay to allow the full coating to adhesively grip the fibers of the backside of the carpet.
As should be apparent, the carpet underlay can be applied at a manufacturing location so that carpet ready for installation can be readily handled and shipped. The underlay is particularly intended, however, for installation of contract carpet on a bare floor, for example,
Ahmad Nasser
Kondracki Edward J.
Miles & Stockbridge P.C.
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