Track control mat and method of making the same

Details Track control mat and method of making the same Track control mat and method of making the same

1997-05-06

2002-10-22

Juska, Cheryl A. (Department: 1771)

Stock material or miscellaneous articles

Pile or nap type surface or component

Particular shape or structure of pile

C428S095000, C428S097000, C156S072000, C015S215000, C015S217000

Reexamination Certificate

active

06468622

ABSTRACT:

TECHNICAL FIELD
The present invention relates generally to carpet, and more particularly relates to an improved carpet with coarse and fine fibers, and a process for making the same. The carpet, when used as a mat, removes large and small dirt particles from footwear due to improved grit and particulate gripping and moisture absorbing capabilities.
BACKGROUND OF THE INVENTION
Many different carpets exist for varied purposes. Carpets are manufactured generally by feeding yarn from spools through needles into a substrate. This process is known in the art as “tufting.” The type of yarn, length of needle, the needle spacing, and whether the yarn is looped or cut are just a few factors that relate to the final carpet product and its intended use. This invention relates to carpet that is manufactured for use in making mats, such as welcome mats or “track control” mats as they are known in the industry.
Typically, track control mats are placed at or near an entrance of a house or other building to remove dirt, moisture or other matter from the bottom of the shoes, and conveyances (such as grocery carts and dollies) used by persons entering the building. The wiping action should occur as the result of normal walking of one or two steps on the mat before the persons walk through the interior of the building.
To prevent dirt and moisture from being tracked from outside throughout the interior of the building, the mats must not only have the ability to remove moisture and dirt from footwear, but also to store the dirt and moisture within the body of the mat. If a mat does not effectively store the dirt and moisture within the mat, and leaves the dirt and moisture on the surface of the mat, the dirt and moisture will re-attach or stick to the bottom of footwear of other persons who subsequently walk on the mat. Dirt and moisture which re-attaches or sticks in this manner will then be tracked throughout the building, a condition known in the art as “re-tracking”.
Some types of track control mats are made of a combination of coarse and fine fibers or filaments (hereinafter collectively referred to as “fibers”). These mats have been widely used in the past for the purpose of removing soil, moisture and other matter from a person's shoes or outer footwear. The coarse fibers help to remove large particles of dirt and the fine fibers help to remove the fine particulate and moisture. There should be sufficient space between fibers to temporarily hold dirt and moisture to prevent re-tracking.
The intended use of a mat relates to the manner in which the mat is constructed. For example, if a mat will be exposed to significant moisture, the mat may be designed to contain a greater number of fine fibers to absorb and hold the moisture within its recesses. On the other hand, a mat that may be exposed to a significant amount of large particles of dirt may need to have a greater number of coarse fibers.
The degree of coarseness or fineness of a fiber is measured by its denier. The term “denier” refers to the weight in grams for a 9,000 meter fiber. A coarse fiber or filament for use in track control mats typically ranges in denier from 100 to 2,000 denier per filament (“dpf”); and fine fibers for the same application typically range from 15 to 100 dpf.
Commercial and public buildings receive large volumes of pedestrian traffic. As a result, the mats in these buildings should be able to remove and store large quantities of dirt and moisture on a daily basis. For continuously effective dirt removal, most mats should be cleaned periodically so that the dirt and moisture stored within the mat are removed. The most effective way to clean mats is to wash them. Some mats cannot be washed due to the types of materials used and method employed in manufacturing the mat. Mats that cannot be washed and reused have a limited effectiveness or lifetime.
Most track control mats are made with a backing that holds the tufts in place relative to the substrate. The backing is typically a plastic or rubber material that is melted or vulcanized and applied to the substrate. In this state, the backing bonds the tufts to the substrate.
Because of the desirability for periodic washings, mats should be manufactured in a manner that will withstand continued exposure to washing and drying. The materials used to make the mat should be able to withstand elevated temperatures in both the washing and drying processes. In addition, mats should be constructed so that the tufts do not separate from the backing during the cleaning process. Adhesion of the tufts to the carpet backing is known as “tuft lock.” Many commercially available track control mats at present exhibit poor tuft lock and, as a result, are ineffective for reuse after washing.
Other types of track control mats already exist. In U.S. Pat. No. 4,045,605 (“the '605 patent”) issued to Breens et al., coarse and fine fibers are used to create one type of track control mat. Breens et al. describes consecutively feeding coarse and fine fibers into the tufting machine from two separate sources. In addition, according to Breens et al., the coarse and fine fibers can be alternately fed to the tufting machine to create alternating areas of course and fine fibers on the mat. While this type of track control mat appears to be effective in removing undesirable dirt and other particles from footwear, it is susceptible to wear out in a short period of time. The concentrated areas of stiff fibers exhibits poor tuft lock and become dislodged from the track control mat during use as well as during washing and drying. Moreover, the concentrated areas of stiff fibers, described in Breens et al., tend to lie down against the backing. Conversely, if the mat were manufactured to provide sufficient stability for the coarse fibers, the fine fibers would have to be so densely tufted to support the coarse fibers inserted therein that the mat would be completely ineffective in retaining dirt or moisture.
U.S. Pat. No. 4,820,566 (“the '566 patent”) and U.S. Pat. No. 5,055,333 (“the '333 patent”), both issued to Heine et al., also describe the use of a mixture of fine and coarse fibers tufted to form a track control mat. The '566 and '333 patents teach that the coarse fibers should be separated from the fine fibers, typically to form a striped or checkerboard arrangement between the two types of fibers. While this type of track control mat may be effective at removing and storing dirt and other particles from the bottoms of shoes, the coarse fibers tend to become dislodged during use or washing of the mat because they are not adequately secured to the mat backing. The tuft lock for these fibers is poor because when the coarse fibers are bonded to the backing at separate locations from the fine fibers, the coarse fibers do not bond well by themselves to the backing. Thus, when the mat is used and washed, many of the coarse fibers become dislodged from the backing. This renders the mat less effective in dirt and moisture removal and storage after a short period of time.
The '566 patent also describes a mat made with at least some crimped coarse fibers. Mats manufactured in accordance with the '566 patent are extremely difficult to manufacture because the crimped fibers kink up as they are fed through the tufting needles which causes the fibers to eventually break. This requires the entire process to be shut down, the needles rethreaded and the process restarted. The continuous kinking and ultimate breakage of the crimped coarse fibers results in a poor quality mat having many broken coarse fibers and many unattractive knots where the crimped fibers had to be reknotted or spliced to continue the tufting process. The frequent breakage of the crimped coarse fibers results in a significant decrease in productivity. In addition, mats using crimped fibers are also more expensive to manufacture due to the added process cost of crimping the fiber.
The '333 patent describes a mat made with at least one looped, uncrimped, coarse fiber. While mats made in accordance wit

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