Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Cellular products or processes of preparing a cellular...
Reexamination Certificate
2001-06-06
2004-07-27
Cooney, Jr., John M. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Cellular products or processes of preparing a cellular...
C521S155000, C521S170000
Reexamination Certificate
active
06767932
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to methods and apparatus for producing a discretely striped, multi-property foam and the products and articles produced thereby.
Polyol foams and their methods of manufacture are well known. These foams have many applications including: cushioning for furniture; padding for underlying carpets; seals and gaskets for a variety of uses; acoustical applications; textile laminates; energy absorbing materials; clothing; sponges; and numerous other products. Conventionally, these foams are made with homogeneous properties, and are typically monotone in color and uniform in their physical properties.
Generally, production of such foams is done with a “one shot” system where components, such as polyether or polyester polyols, surfactants and amine catalysts, flame retardants, blowing agents and other specialty additives are held separately and metered individually into a mixing chamber. The mixture of these components is “non-reactant”, i.e. it has not begun the foaming process. Typically to initiate a chemical reaction an isocyanate is added which starts the foaming reaction process. The combination of these components in a mixture creates a pre-foam stream, i.e. a stream that has begun the reacting process but has not yet foamed. To combine the “non-reactant” components and isocyanate streams thoroughly, the “non-reactant” components and the isocyanate stream are passed through a mixing head. Typically the “non-reactant” components enter first with the additive streams and isocyanate entering immediately thereafter. The components are thoroughly intermixed and deposited on a surface or passed through a trough device to rise and cure. Further processing may then be performed on the cured foam to achieve a desired final product. However, the result of the typical foaming process is a foam product with a uniform, homogeneous set of properties.
Several attempts have been made to increase color variety in foam products but such processes have significant drawbacks rendering production of such foams prohibitively expensive and undesirable for various applications.
A marbleization process, although increasing the variety of colors in the resultant foams, does not provide foams with a separation of one color from those of another in a repeatable, discrete pattern. This process introduces a colorant into the foam mix in an intermittent fashion such that the foam coloration is intermixed and marbleized, as seen in
FIGS. 1 and 2
of Japanese patent JP62263028. This process cannot achieve discretely striped foam with a variation in color. A more regular, controlled pattern is often desired in products, for instance in the area of clothing, blankets, and novelty items to achieve a particular visual effect. The intermixing of colors in the marbleization process is so significant that no controlled visual effect is achievable. The marbleization process is only capable of providing an end product that is a wild jumble of colors.
A process to merge continuous disparate reactant foaming streams of different colors in a single foam product with heterogenous regions of color is described in U.S. Pat. No. 3,904,557. The multiple reactant streams flow in parallel and are in a liquid form when poured. Preferably they are poured through a “heterogenous blender”, separating each stream with a divider plate, while mixing the compositions between the plates to promote the foaming process. Some intermixing inherently occurs when the streams hit the surface upon which they are being laid out or, alternatively, may be intentionally provided as suggested by the reference. This is likely to create a variegated pattern within the foam mass, similar to marbleization. The '557 process then attempts to lay up the two streams of foam while they cure or just after they are poured next to one another. The resulting product inherently has a seam which would be susceptible to separation, thus making the use of these products impractical at best in any application requiring durability, such as cleaning products, blankets and clothing. The '557 process also suffers from the increased costs in labor, machines and space for mixing, pouring, transporting and curing the multiple foam streams prior to laying them up to bond.
SUMMARY OF THE INVENTION
Despite numerous past efforts, no process has been able to achieve a cost effective, discretely striped, multi-property, segmented foam. There exists a need for a method and apparatus to produce a product having discretely striped, multi-property segments that are varied to provide distinct differentiation of properties between the segments. Such an apparatus and method would allow for increased flexibility in the variety of applications in which such a foam could be used and greater variety, particularly in the coloration of foams in general. The new system must be cost effective, preferably needing only a single foam stream. The new system should provide a durable, repeatable, discretely striped foam for commercial applications. For instance, specific commercial applications that would benefit include but are not limited to the production of blankets, clothing articles, novelty items, and similar applications.
An object of the invention is to provide a method and apparatus for producing a foam product with repeatable, discretely striped multi-property segments.
A further object of the invention is to provide a cost-effective process to produce seamless repeatable, striped, multi-property, segmented foams requiring no adhesives or bonding.
Another object of the invention is to provide a process of producing multi-property foam in a single stream.
A still further object of the invention is to provide a mixing head for manufacturing repeatable, striped, multi-property, segmented foam.
An additional object of the invention is a distinct and predictable, striped, multi-property segmented foam product.
The invention provides a process, and a foam product produced by the process, comprising the steps of providing a pre-foam stream at a first pressure, intermittently injecting an additive into the pre-foam stream at a pressure higher than the first pressure, providing a laminar flow pre-foam stream with alternating segments, pouring said laminar flow pre-foam stream onto a surface, and curing said pre-foam stream into a foam product having discrete alternating stripes or segments with different properties.
The stripes or segments of the foam can vary in chemical composition. Preferably, the additive is a coloring agent and the alternating stripes or segments vary in color. The additive may vary given ratios of at least one of a polyol, an isocyanate, and water. The product may have two or more different types of alternating stripes. The product may be a clothing article or a blanket or an insulator.
The method may further comprise the step of conveying the poured pre-foam stream in a direction generally perpendicular to the direction of pouring of the pre-foam stream. The pre-foam stream can be poured at an angle to minimize the intermixing of the pre-foam stream. The segments of the alternatingly segmented pre-foam stream are preferably generally perpendicular to the flow of the pre-foam stream. The segmented pre-foam stream can also be poured to produce an alternatingly striped foam bun rotatable about an axis of rotation. The method can further comprise pouring the pre-foam stream into a cylindrical or a rectangular form. The method can further comprise the step of pouring the pre-foam stream into a trough.
The method may also comprise peeling a striped layer or sheet of foam from the circumference of the foam bun to provide stripes generally at an angle to the axis of the cylindrical bun. The method can also include cutting a rectangular or other discretely striped foam shape from the bun.
The pre-foam stream can be provided by mixing a non-reactant stream with an isocyanate to produce a pre-foam stream. The method can include injecting the at least one additive into a laminar flow region of the pre-foam stream, providing a l
Kelly David J.
Tolen George J.
Anderson Chad C.
Cooney Jr. John M.
Gollin Michael A.
Venable LLP
Wm. T. Burnett & Co.
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