Multi scrim non-slip pad and method of manufacture

Details Multi scrim non-slip pad and method of manufacture Multi scrim non-slip pad and method of manufacture

2001-12-04

2004-01-06

Yao, Sam Chuan (Department: 1733)

Adhesive bonding and miscellaneous chemical manufacture

Methods

Surface bonding and/or assembly therefor

C442S009000, C442S022000, C442S030000, C442S032000, C442S045000, C442S055000, C442S056000, C428S308400

Reexamination Certificate

active

06673179

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates a non-slip product and method of its manufacture and, more particularly, to a non-slip pad having multiple scrims each coated with liquid polyvinyl chloride (PVC) which are then baked in an oven to form foam coating layers around the scrims.
2. Description of Related Art
Several manufacturers, including the assignee of this application, make and sell a number of non-slip products including rug pads, work bench pads, tool box pads, kitchen drawer inserts, automobile cargo pads, and other products. These products provide a barrier between two surfaces which resist one surface moving, or slipping, relative to the other. An additional feature of most non-slip products is protection of at least one of the surfaces from scratching or denting. Some non-slip products also provide a cushioning effect, such as some rug pads, when weight is applied to the pad.
Non-slip products are typically manufactured utilizing a single knitted polyester scrim which may be purchased from manufacturers including Milliken, Supertex, and Cortina. The scrim is provided in rolls and is fed through a vat of liquid polyvinyl chloride which coats at least portions of the scrim. The coated scrim is then fed into an oven where it is baked as it passes through the oven. The coating forms a solid foam coating during the curing process in the oven. Once the product exits the oven, it is rolled or otherwise delivered for further processing including cutting to a desired size.
A variety of scrims and polyvinyl chloride products are available on the market. Some prior art scrims have relatively large apertures as shown in FIG.
1
. These types of scrims are typically utilized so that when polyvinyl chloride (PVC) coating is applied, the PVC does not fill the apertures, but coats the threads and the kilots. U.S. Pat. No. 6,130,174 illustrates this effect in FIGS. 1 and 3. There are a number of advantages of this product configuration for some applications.
Another scrim type is shown in
FIG. 2
which is very similar to FIG. 6 of U.S. Pat. No. 5,906,878. Some of the apertures in this scrim type contain thread members. The coated version of this scrim is illustrated in FIGS. 3 and 4 of the '878 Patent which provide alternating coated apertures. This product configuration has advantages for some applications as well.
A third scrim type is also utilized for some products wherein the majority, if not all, of the apertures contain thread members so that the majority, if not all, of the apertures are substantially completely coated during the coating process. The resulting coated scrim often forms a “sheet” or is substantially solid (i.e., few if any holes in the coated product or alternatively very small holes) and has a number of advantages for particular applications.
FIG. 3
is a prior art scrim of this configuration. As one can see, the type of scrim utilized often effects the porosity, as well as amount of coating retained by the scrim.
The particular polyvinyl chloride (PVC) product utilized also affects the finished product. A number of manufacturers supply suitable PVC products. Some polyvinyl chloride products may be more, or less, viscous than others so that the thickness of the foam formed may be a function of the viscosity of the polyvinyl chloride product. Other characteristics of the particular polyvinyl chloride product utilized have also been found to effect the characteristics of the foam coating.
Finally, the temperature and time of exposure to temperature affects the finished pad product. Most ovens are believed to operate between about three hundred fifty and four hundred degrees Fahrenheit. The coated material is typically gripped by its edges and it is transported through the oven in a substantially horizontal manner. The speed of the coated material proceeding through the oven may be a function of the curing time needed to cure the liquid coating into a solid foam product about the polyester scrim.
While the scrim configuration, the chemical composition of the polyvinyl chloride product, and the time and temperature have been varied to achieve different non-slip products, a need still exists to provide a non-slip product which incorporates advantages of a number of non-slip products. Specifically, one client requested a non-slip product which would have a cushioning effect which is normally achieved with a sheet like coating made utilizing a scrim which is almost completely, if not completely coated. The client also wanted a textured top surface, such as one having a “raison” feel. Unsuccessful attempts were made utilizing various single scrim types and varying the amount and types of polyvinyl chloride coating placed on the single scrim as well as varying the time and temperature of the curing process in the oven.
These experiments produced a variety of results. As the amount of coating placed on the scrim increased, the scrim was placed under increased tension due to the weight of the coating as it was fed through the oven. Some scrims tore when overloaded. Varying the time in the oven and heat of the oven also had an undesirable effect in a number of attempts. Overcuring of coated products sometimes resulted in an undesirable “popcorn” effect where the “bubbles” within the foam burst. Accordingly, a need exists for providing another method of manufacturing with a resulting new non-slip product.
SUMMARY OF THE INVENTION
The present invention recognizes and addresses these needs and others.
Consequently, it is an object of the present invention to provide a non-slip pad which combines advantageous aspects of multiple non-slip products.
It is another object of the present invention to provide a non-slip pad and method of manufacture to provide a plurality of scrims located in a substantially parallel configuration, each of the scrims being coated with polyvinyl chloride foam.
It is another object of the present invention to provide a non-slip pad and method of manufacture which incorporates a plurality of coated scrims.
Accordingly, the present invention provides a multi-scrim non-slip pad and method of its manufacture. The non-slip pad is manufactured by coating a first scrim with a first coating of a first polyvinyl coating. The first coating may be partially cured at this time by processing in an oven. A second scrim is then coated with a second coating which may be of the first or of a second polyvinyl coating and the second coated scrim is applied to the first coated scrim. The multi-scrim product is then processed in the oven to cure the first and second coatings which also forms a “weld” which is where the two coatings join one another in a mechanical fashion.
Utilizing this method of manufacture, the first and the second scrim may have different configurations such as a first scrim which forms a substantially solid sheet when coated and a second scrim which retains a configuration of at least some apertures through the coated second scrim. This allows for combining advantages of both scrim configurations. If the second scrim is placed on top of the first scrim, the substantially solid bottom will be below the textured top. This has been found advantageous in the creation of yoga mats, as well as tool box pads for certain applications. Other applications may be found for the new pads as well. For this product configuration, the non-slip pad has good cushioning characteristics while providing the desired textured top surface. Other applications may be found for the new pads as well.


REFERENCES:
patent: 4594284 (1986-06-01), Nakagawa et al.

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