Stock material or miscellaneous articles – Pile or nap type surface or component – Particular backing structure or composition
Reexamination Certificate
1998-03-30
2001-04-17
Morris, Terrel (Department: 1771)
Stock material or miscellaneous articles
Pile or nap type surface or component
Particular backing structure or composition
C428S096000
Reexamination Certificate
active
06217974
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a new carpet structure with increased dimensional stability and integrity, and particularly one which is useful with a hook and loop installation system as disclosed in for example U.S. Pat. No. 4,822,658.
BACKGROUND OF THE INVENTION
Most carpets have some form of dimensional stability problems due to changes in temperature and humidity and also due, in some cases, to the lack of integrity from high traffic and heavy rolling stock etc. These problems are particularly acute when nylon is used as the primary pile layer since nylon absorbs moisture and expands up to approximately 6% of its weight. In many other ways, however, nylon is a preferred form of material for use in making carpet because of its durability and cost.
Typically nylon is used to make the pile of the carpet and it is tufted into a polypropylene primary backing to which it is bound by a predominantly latex binder applied to the underside of the backing.
The nylon pile tufted into the primary backing by itself is flexible and relatively stable, resisting buckling or wrinkling from atmospheric changes in moisture or temperature. However, this intermediate product does not have the stability, mass or tuft bind to be a carpet. It is a mere piece of textile. Typically, integrity is added to this primary backing by the addition of a latex binder to bind the tuft bundles left below the primary backing together to add weight, stability and durability to the backing. However, as soon as this is done, problems can arise because of fiber growth in the primary pile due to atmospheric changes in relative humidity and temperature, leading to increased stress on the carpet as a whole. This can result in wrinkling, buckles and delamination, and in heavy traffic zones, reduce carpet integrity.
As disclosed in U.S. Pat. No. 4,822,658, a method has been developed of installing a carpet through the use of a hook and loop system. The most economical form of such installation is the attachment of the carpet at the perimeter and along the seams. This is essentially a “free float system”. It is therefore desirable in such a system to have a carpet of inherent dimensional stability and integrity, particularly under conditions of humidity changes and high traffic.
Attempts have been made to prevent the growing and distortion of some forms of carpet, especially carpet tiles or carpets of 6 feet width or less, by making it heavier and heavier and by locking the nylon of the pile into the backing more rigidly with more and more binder, adhesive or glue. Other attempts have been made to give greater dimensional stability to the carpet by putting fiberglass into the backing. While these attempts can create more dimensional stability, they do not completely satisfy the need for atmospheric stability and integrity for the great majority of carpets, particularly wide width carpets of greater than 6 feet. Most such carpets still require adhesion to the floor across substantially all of their underside, typically by gluing to maintain atmospheric stability and integrity. This construction thus makes it difficult to install a carpet in a “free-float” system, i.e. one in which the carpet is installed only along its perimeter and seams.
One approach to this problem has been to moisten the carpet during installation prior to securing the carpet to the floor, as described in U.S. Pat. No. 5,479,755, issued to Pacione on Jan. 2, 1996. Moistening is done to deliberately cause the carpet to expand and then the carpet is affixed in place by the hook and loop system. This approach, however, does not teach how to obtain a carpet which does not swell to begin with when the nylon pile fibres become wet.
Also since carpet piles can differ, since the required stability and strength of carpets varies widely depending upon the anticipated use, and since cost plays a part in an item like carpet which is supplied in very large volume, it is desirable to have a series of constructions which can be used to engineer a carpet to a desired stability according to predetermined criteria so as to meet the anticipated conditions of use and cost. It is helpful if such constructions are able to be selected as required to achieve a predetermined selected dimensional stability and level of required integrity.
SUMMARY OF THE INVENTION
The invention is achieved in part by recognizing, on the one hand, that increasing binder weight and density on the underside of the primary layer aggravates, rather than alleviates, the atmospheric stability problem in carpets and by the further recognition that flexible dimensionally stable light weight secondary layers can be added as needed as backings to give the required stability to the primary layer.
The present invention provides a carpet structure and backing of superior dimensional stability and integrity which is especially useful in a free float system of installation.
In one aspect of the invention, a carpet is provided having a selected dimensional stability comprising:
(i) a first carpet part comprising a primary layer with pile substantially covering a first side of the layer, the pile tufted through the primary layer to leave tuft bundles on a second side of the primary layer and a binder encapsulating the tuft bundles, the first part having a predetermined force of expansion and contraction under cycling conditions of temperature and moisture;
(ii) a second part in layered relationship to the first carpet part, the second carpet part constructed from one or more layers to have a predetermined resistance to expansion and contraction at least equal to or greater than the force of expansion and contraction of the first carpet part under cycling conditions of temperature and moisture and traffic loads on the carpet pile.
In another aspect, carpet backing for use on a carpet to be installed on a floor by means of hooks complimentary and attachable to loops on the back of such backing is provided comprising:
(i) a first spun web layer;
(ii) loops needled into and through the first layer to substantially cover a first side of the layer with exposed loops;
(iii) a binder on the second side of the layer to lock the loops into the layer.
Here, the substrate of the backing can be thermally bonded to stabilize the substrate.
The substrate can be point bonded.
The substrate can be non-woven.
A second layer of spun web substrate can be adhered to the first layer on the side opposite the exposed loops.
The binder can also bond the first and second layers together.
The second layer can be non-woven.
The second layer can be point bonded.
Additional spun web layers of the backing can be adhered as needed to create a carpet of a selected dimensional stability.
The first layer can be spun web non-woven thermally bonded polyester.
The binder can contain a fire retardant chemical treatment.
Loops can be needled into the first layer by the malimo process.
The amount and viscosity of the binder on the second side of the substrate can be matched with the density of the substrate so that such binder penetrates both sides of the substrate to lock the loops into the substrate but without clogging the loops on the first side.
In another aspect, the invention is a carpet having a selected dimensional stability comprising:
(i) a first carpet part comprising a primary layer with pile substantially covering a first side of the layer, the pile tufted through the primary layer to leave tuft bundles on a second side of the primary layer and a binder encapsulating the tuft bundles, the first part having a predetermined force of expansion and contraction under cycling conditions of temperature and moisture;
(ii) a second part in layered relationship to the first carpet part, the second carpet part constructed from one or more layers to have a predetermined resistance to expansion and contraction at least equal to or greater than the force of expansion and contraction of the first carpet part under cycling conditions of temperature and moisture and traffic loads on the carpet pile.
The second carpet part can be constru
Blake Cassels & Graydon LLP
Gray Brian W.
Hunt John C.
Juska Cheryl
Morris Terrel
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