Agitating – Having specified feed means – Returning material to supply
Reexamination Certificate
1999-06-17
2001-06-19
Cooley, Charles E. (Department: 1723)
Agitating
Having specified feed means
Returning material to supply
C366S173100, C366S182400, C251S315160
Reexamination Certificate
active
06247839
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an improved procedure and apparatus for making colored polyurethane foam products, such as carpet underlay and the like, as well as the improved colored product itself. Such a procedure entails the utilization of at least one valve assembly within a color dosing manifold such that the valve itself is simultaneously in contact with both the outside surface and the inside surface of the manifold. Such a disposition for a valve assembly permits color to be introduced directly into a binder (i.e., polyol and isocyanate) or polyol stream in order to substantially eliminate any color remaining in contact solely with the inside walls of the manifold. This in turn permits thorough mixing of the binder and colorant and substantially reduces the response time from opening the valve to producing colored polyurethane materials (such as polyurethane foam), thereby effectively eliminating the production of waste polyurethane product. The inventive configuration comprising a specific type of ball valve and/or the placement of a plurality of such disposed valves in a radial configuration on the manifold are also contemplated within the invention.
BACKGROUND OF THE INVENTION
Polyurethane foam carpet underlay products are utilized to provide cushioning benefits for pedestrians since carpet is usually placed over hard floors, such as concrete or wood. Such carpet underlay thus should provide a uniform and even cushioning effect over the entire covered area. Furthermore, there are certain aesthetic qualities which are demanded in the marketplace for such carpet underlay products as concerns colorations and appearances. These demands have been met in the past through the utilization and introduction of colorants through one or more pipes or injectors, arranged consecutively and serially (if a plurality is present), through connections (feed lines, etc.) feeding to a manifold, and ultimately into binder compositions comprising the standard polyurethane reactants (polyols, such as ether triols, and the like, and isocyanates, such as methyl diphenyl diisocyanate, and the like, as merely examples; any standard polyol and isocyanate utilized to produce polyurethane in this industry may be used). The pipes or valve assemblies have been disposed in the past by merely creating a hole in the manifold to which the pipe or valve assembly is attached. The colorant would then be fed (by pressure or gravity, for instance) through the pipe or valve assembly and emptied into the binder stream travelling through the manifold. These colored compositions are generally mixed by a binder pump and sprayed onto scrap foam to form the desired carpet underlay product. Such a standard method has proven inefficient and problematic in the past since the through-pressure of the travelling binder stream is not always constant and thus the mere introduction at the walls of the manifold has not provided sufficient ability to thoroughly mix the colorant within the binder stream (in fact, the colorant remains in contact with the manifold wall rather than being “injected” into middle of the binder stream). This procedure thus leads to uneven coloring, discolorations, coagulation of binder and colorant, and the production of undesirable and potentially costly waste foam.
As a result, the demand for the introduction of a wide variety of colors in binder compositions for the production of polyurethane foam carpet underlay products has resulted in a significant move to blend-on-fly color dosing units based on the use of polymeric colorants. In this case color metering equipment is used to accurately dose two or more colors that are injected into the polyol stream and subsequently mixed in a binder pump to provide the correct shade and depth of color. The biggest advantage of this type of approach is that now an unlimited number of colors can be made from 1 to 5 “primary” colors blended on-the-fly. For example, a typical colored polyurethane product, carpet underlay, is colored and produced through a system based upon a binder/colorant shot process (i.e., color is introduced simultaneously with the start of a binder pump and stops when the pump is shut off, thus eliminating the introduction of additional color into the manifold). Changes from light and/or dark shades and color changes from one hue to another can be accomplished with a minimal amount of binder flush through the manifold thus reducing the amount of off-quality foam produced during the color change procedure. Thus, changes from one dark color to the next can usually be accomplished in relatively short distances minimizing the amount of foam that must be scrapped as a result of the color change. Light shades have proven to be more of a challenge since the color throughput is substantially lower causing the response time to increase before changes actually made in the system can take effect. As a result, a means was needed to reduce this response time to an acceptable level thus minimizing the length of time required to change from one color to the next even at low flow rates (approaching 2 grams per minute or less.)
A means was also needed to produce even colorations in the final product, as well as to possibly reduce the amount of coagulated binder/colorant (that is coagulated or crystallized portions of the colorant combined with the polyol and the isocyanate of the binder composition). Such a coagulant theoretically produces patches or areas of “hardness” within the carpet underlay product. As such a product desirably provides a uniformly cushioned, soft feel as a layer between the carpet and the hard floor underneath, any coagulated binder/colorant will produce unwanted, deleterious areas of “hardness.”
Thus, it was necessary to develop a configuration and/or utilize, within this specific configuration, a specific valve assembly in order to facilitate effective on-the-fly polymeric colorant blending with even colorations in the final product and substantially reduced, if not eliminated, binder/colorant coagulant production. To do this it was first necessary to realize that the current standard configuration utilized either a single colorant “injector” (i.e., pipe, valve, etc.) on the dosing manifold, or a plurality of “injectors” aligned consecutively and serially on the manifold (i.e., one after the other), such that the “injectors” would merely be used to transfer colorant to a location in very close proximity to the manifold inner wall. Such a limited manner of “injecting” colorant resulted in the problems discussed above since the colorant would not become thoroughly mixed and, in conjunction with the laminar flow of the binder through the manifold, would basically remain in contact with the manifold rather than become thoroughly mixed within the binder stream. Thus, it was reasoned that the main problem with the traditional method of producing polyurethane foam could be alleviated through the utilization of a newly modified valve assembly which extends within the actual manifold rather than remains at a location outside the manifold. Accordingly, this invention provides apparatus for the production of polyurethane foam carpet underlay comprising a mechanism for the introduction of colorant within a binder composition; wherein said apparatus comprises a manifold comprising an inside surface and an outside surface, within which said binder composition and said colorants are mixed together, which leads to a binder pump; wherein said apparatus comprises at least one valve assembly through which said colorants are transferred from a feed line to said manifold; and wherein said at least one valve assembly is disposed within said manifold such that said at least one valve assembly is simultaneously in contact with both said outside surface and said inside surface of said manifold.
Furthermore, in other polyurethane producing procedures, colorants have traditionally been added strictly to the polyol component prior to its ultimate reaction with isocyanate to form the target polyurethane article (such as foam, carpet underla
Chavis Jimmy D.
Kochanowicz Christopher T.
Pitman F. Mark
Ragsdale Mark E.
Cooley Charles E.
Milliken & Company
Moyer Terry T.
Parks William S.
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