Stock material or miscellaneous articles – Pile or nap type surface or component – Composition of pile or adhesive
Reexamination Certificate
2000-05-26
2003-04-29
Juska, Cheryl A. (Department: 1771)
Stock material or miscellaneous articles
Pile or nap type surface or component
Composition of pile or adhesive
C428S095000, C428S096000, C521S101000, C521S159000
Reexamination Certificate
active
06555199
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to polyurethane-backed articles. The present invention particularly relates to polyurethane-backed articles and to a process and composition used in making same.
Articles having attached polyurethane foam layers are well known. For example, carpets and other substrates having attached polyurethane foam layers as backing are described in U.S. Pat. Nos.: 3,755,212; 3,821,130; 3,862,879; 4,022,941; 4,171,395; 4,278,482; 4,286,003; 4,296,159; 4,405,393; 4,483,894; 4,512,831; 4,515,646; 4,595,436; 4,611,044; 4,657,790; 4,696,849; 4,853,054; 4,853,280 and, 5,104,693. Typically a filler material is used to prepare a polyurethane formulation for carpet backing. The filler can replace some of the polymer required to prepare a polyurethane backed article, while maintaining bulk in the article. This can lower the cost of production of the article, since materials used as fillers are typically less expensive than the polymer material that is being replaced.
In selecting a filler for a particular application, the effect that the filler can have on the process—and on the physical properties of the article—should be considered. For example, in a process for preparing polyurethane backed carpets, a filler that is too alkaline can cause premature gellation. Conversely, a filler that is too acidic can cause an unacceptable delay in the onset of gellation. Increasing the amount of conventional fillers used in preparing carpet backing, such as calcium carbonate (CaCO
3
) and aluminum trihydrate (ATH), can result in an undesirable viscosity increase in a polyurethane formulation.
While cost reduction can be an incentive for introducing as much filler as possible into a polyurethane formulation, it can be unacceptable to reduce the cost of production at the expense of the quality of the article produced. The amount of filler incorporated into a polyurethane formulation can be limited by the adverse effects that the filler can have on the properties of a polyurethane, such as flexibility, resiliency, and adhesion, for example.
Fly ash has been used as a filler material in systems such as cement and concrete products, roadbases/subbases, and structural fills. See, for example, U.S. Department of Transportation/Federal Highway Administration Report No. FHWA-SA-94-081 (August 1995). The Electric Power Research Institute (EPRI), in EPRI Report CS-4765 (September 1986) (hereinafter CS-4765), reported that fly ash recovered from a direct acid leaching process was added as a filler to polymerized nylon and polypropylene.
It would be desirable to increase the loading of filler into a polyurethane formulation without detriment to the process of preparing a polyurethane carpet backing, or to the final physical properties of the final product. It would also be desirable to use fly ash as a filler material in a reactive polymeric system without significant effect on a polymer forming reaction.
SUMMARY OF THE INVENTION
In one aspect, the present invention is a polyurethane-forming composition, useful for preparing a polyurethane precoat, polyurethane laminate coat, or polyurethane foam coat comprising a polyol; a chain extender; a polyisocyanate; a catalyst; a surfactant; a filler wetting agent; and a filler, wherein the filler includes fly ash; and optionally including a surfactant and a blowing agent.
In another aspect, the present invention is a backed carpet having a polyurethane backing that includes at least one coat of polyurethane that is prepared from a polyurethane-forming composition comprising a polyol; a chain extender; a polyisocyanate; a catalyst; a filler wetting agent; a filler, wherein the filler includes fly ash; and optionally including a surfactant and a blowing agent.
In still another aspect, the present invention is a process for preparing a carpet having a polyurethane backing comprising the steps: (1) applying at least one layer of a polyurethane-forming composition to a carpet substrate, wherein the polyurethane-forming composition includes fly ash; and (2) curing the polyurethane-forming composition to form a tack-free polyurethane backing. Applicant has developed a process for preparing a polyurethane composition which incorporates fly ash as a filler material. The process of the present invention can result in an improved process, including increased flow of a polyurethane composition into the backstitch of a carpet, and increased pot life of a polyurethane composition. The use of fly ash as filler reduces pilling and fuzzing of the carpet face, improves flexibility of the carpet during installation, and also reduces puddle gellation during application of a polyurethane-forming composition. In addition, fly ash can be included at a higher loading than conventional fillers, without detriment to established process parameters or to the physical properties of a polyurethane carpet backing.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The polyurethane-forming composition of the present invention comprises a polyol as described herein, a chain extender, a polyisocyanate, a catalyst as described herein, a surfactant, a filler wetting agent, and a filler that includes fly ash. The composition of the present invention contains reactive components such as active hydrogen containing compounds and compounds having isocyanate functionality.
Active hydrogen containing compounds are compounds having active hydrogen functionality, wherein at least one hydrogen atom is bonded to an electronegative atom such as sulfur, nitrogen, or oxygen. Active hydrogen containing compounds described herein can contain any combination of hydroxyl , amino, and mercaptyl functionality—in addition to other active hydrogen groups—and can be reacted with isocyanate groups under conditions suitable for preparing a polyurethane carpet backing. The average functionality of an active hydrogen containing compound refers to the average number of active hydrogen groups per compound.
A polyol is an example of an active hydrogen containing compound, in the present invention. As used herein, the term “polyol” can refer to a single polyol or to a mixture of two or more polyols. A polyol of the present invention can have an average equivalent weight of from about 500 to about 5000, preferably from about 750 to about 2500, and more preferably from about 750 to about 2000. The average equivalent weight of a compound can be determined by dividing the average molecular weight of the compound by the functionality of the compound. In the present invention, at least about 30 percent, preferably about 50 percent, and more preferably about 60 percent of the hydroxyl functionality of a polyol is primary hydroxyl functionality. While a wide range of materials can be used, polyether polyols are preferred based on their performance and wide availability. Polymers of propylene oxide which are at least partially end-capped with ethylene oxide are particularly preferred.
Polyols of the present invention are prepared by known methods by reacting an alkylene oxide with a suitable polyhydric initiator compound. The alkylene oxide preferably has 2-8 carbon atoms. For example suitable alkylene oxides can be ethylene oxide, propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, styrene oxide, epichlorohydrin, 3-methyl-1,2-butylene oxide, like compounds and mixtures thereof, with propylene oxide being the preferred oxide. The initiator compound can be a polyhydric compound such as water, ethylene glycol, propylene glycol, 1,2-butane diol, 1,3-butane diol, glycerine, trimethylol propane, p,p′-isopropylidine diphenol, aniline, ammonia, ethylene diamine, aminoethylethanolamine, like compounds and mixtures thereof.
When a single polyol is used in the present invention, the polyol can have an average functionality of from about 1.4 to about 3.0. Preferably the average functionality of the polyol is from about 1.6 to about 2.8. A mixture of polyols can be used which includes at least a second polyol in addition to the first polyol. The second polyol can be described in the same manner as the first
Juska Cheryl A.
Locke Liddell & Sapp LLP
The Dow Chemical Company
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