Fabric (woven – knitted – or nonwoven textile or cloth – etc.) – Coated or impregnated woven – knit – or nonwoven fabric which... – Coating or impregnation is specified as weather proof – water...
Reexamination Certificate
1999-12-03
2003-02-25
Morris, Terrel (Department: 1771)
Fabric (woven, knitted, or nonwoven textile or cloth, etc.)
Coated or impregnated woven, knit, or nonwoven fabric which...
Coating or impregnation is specified as weather proof, water...
C442S079000, C442S086000, C428S095000, C428S096000, C524S590000, C524S591000
Reexamination Certificate
active
06524978
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to polyurethane polymers. This invention particularly relates to polyurethane polymers obtained from aqueous polyurethane dispersions.
Polyurethane dispersions are known, and can be used to obtain polyurethane polymers that can themselves be useful in various applications. Polyurethane/urea dispersion s can be used to obtain, for example: carpet backings; coatings for wood finishing; glass fiber sizing; textiles; adhesives; automotive topcoats and primers; films for packaging; gloves, and other applications. Polyurethane dispersions can be prepared by various processes, including, for example, those described in: U.S. Pat. No. 4,857,565; U.S. Pat. No. 4,742,095; U.S. Pat. No. 4,879,322; U.S. Pat. No. 3,437,624; U.S. Pat. No. 5,037,864; U.S. Pat. No. 5,221,710; U.S. Pat. No. 4,237,264; and, U.S. Pat. No. 4,092,286.
Polyurethane dispersions can be obtained according to a process that is described in U.S. application Ser. No. 09/039978. Dispersions prepared according to the process described therein can be useful for obtaining polyurethane carpet backings and polyurethane textile backings. Problems can result, however, in the event that a spill occurs wherein a liquid can flow onto, or be absorbed by, the backing on the underside of a carpet. Spilled liquids such as water, urine, beverage drinks, food, blood, and feces can penetrate a carpet backing to the underside of the carpet, which can be inaccessible to various cleaning methods. Polymeric materials having moisture resistance can be useful in protective wear such as gloves, for example, or packaging.
Various conventional methods can provide a moisture barrier to polymers obtained from aqueous polymeric dispersions. For example, increased coating weights of a dispersion can be used, thereby increasing the thickness of the polymer. Alternatively, wax added to an aqueous polymeric dispersion can provide a moisture barrier to carpet. Another known method for providing a moisture barrier is to decrease the amount of filler used in a carpet backing formulation. A non-permeable fabric or film can also be applied to a carpet backing, as described in U.S. Pat. No. 5,763,040. Still another method involves applying a fluorochemical on the underside of a secondary backing, and is described in U.S. Pat. No. 5,348,785. Use of fluorochemicals to impart water impermeability is also described in U.S. Pat. Nos. 4,619,853 and 4,643,930. A water-impervious film is described in U.S. Pat. No. 4,336,089. Application of various hydrophobic compositions to a secondary backing is described in U.S. Pat. No. 5,558,916.
It would be desirable in the art of preparing polyurethane polymers, to prepare a polyurethane dispersion that includes a component that imparts a moisture barrier to a polyurethane polymer, without adding complexity to a manufacturing process, or significantly changing the other properties of the polyurethane polymer. It would also be desirable in the art to prepare such a polymer by a process that would not significantly increase the cost of manufacture of the polymer, or articles produced therefrom.
SUMMARY OF THE INVENTION
In one aspect, the present invention is an aqueous polyurethane dispersion comprising an isocyanate terminated prepolymer prepared from a formulation including a polyisocyanate and a polyol mixture, wherein the polyol mixture includes at least one aliphatic mono, di or polyhydroxy compound which has an aliphatic side chain substituent which contains from 5 to 30 carbon atoms and wherein the aliphatic mono, di or polyhydroxy compound which has an aliphatic side chain substituent is present at a concentration of from 0.5 to 10 weight percent of the polymer.
In another aspect, the present invention is a moisture resistant polyurethane polymer comprising a polymer layer prepared by applying a layer of an aqueous polyurethane dispersion comprising an isocyanate terminated prepolymer prepared from a formulation including a polyisocyanate and a polyol mixture, wherein the polyol mixture includes at least one aliphatic mono, di or polyhydroxy compound which has an aliphatic side chain substituent which contains from 5 to 30 carbon atoms and wherein the aliphatic mono, di or polyhydroxy compound which has an aliphatic side chain substituent is present at a concentration of from 0.5 to 10 weight percent of the polymer to a substrate and allowing the dispersion to cure.
In still another aspect, the present invention is a moisture resistant textile comprising a textile and adherent thereto a polymer prepared by applying a layer of an aqueous polyurethane dispersion comprising an isocyanate terminated prepolymer prepared from a formulation including a polyisocyanate and a polyol mixture, wherein the polyol mixture includes at least one aliphatic mono, di or polyhydroxy compound which has an aliphatic side chain substituent which contains from 5 to 30 carbon atoms and wherein the aliphatic mono, di or polyhydroxy compound which has an aliphatic side chain substituent is present at a concentration of from 0.5 to 10 weight percent of the polymer to the textile and allowing the dispersion to cure.
Moisture resistant polyurethane of the present invention can be useful in cushioned flooring applications such as attached cushion broadloom, carpet tiles, carpet underlay, or vinyl flooring; adhesives applications; coatings; protective clothing or protective gear such as gloves and aprons; packaging; or any application where moisture resistant polymers can be useful.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In one embodiment, the present invention is an aqueous polyurethane dispersion composition that can yield a coating or a foam having good moisture resistance. A polyurethane dispersion of the present invention includes water, and either: a polyurethane; a mixture capable of forming a polyurethane; or a mixture of both. A polyurethane dispersion of the present invention can optionally include: chain extenders; surfactants; fillers; dispersants; foam stabilizers; thickeners; fire retardants, and/or other optional materials that can be useful in a polyurethane formulation.
The polyisocyanate component of the formulations of the present invention can be prepared using any organic polyisocyanates, modified polyisocyanates, isocyanate-based prepolymers, and mixtures thereof. These can include aliphatic and cycloaliphatic isocyanates, but aromatic and especially multifunctional aromatic isocyanates such as 2,4- and 2,6-toluenediisocyanate and the corresponding isomeric mixtures; 4,4′-,2,4′- and 2,2′-diphenyl-methanediisocyanate (MDI) and the corresponding isomeric mixtures; mixtures of 4,4′-, 2,4′- and 2,2′- diphenylmethanediisocyanates and polyphenyl polymethylene polyisocyanates PMDI; and mixtures of PMDI and toluene diisocyanates are preferred. Most preferably, the polyisocyanate used to prepare the prepolymer formulation of the present invention is MDI or PMDI.
A polyurethane dispersion of the present invention is an aqueous dispersion of a polyurethane and/or polyurethane-forming materials. For the purposes of the present invention, polyurethane dispersions can include other polymeric and/or oligomeric compounds including, but not limited to: ureas, biurets, allophonates, and other compounds having functionality that can be derived from the reaction of an isocyanate with the various active hydrogen containing compounds present in the formulation. Polyurethane-forming materials, as the term is used in the present invention, are materials which are capable of forming polyurethane polymers. Polyurethane-forming materials include, for example, polyurethane prepolymers. Prepolymers useful in the practice of the present invention can be prepared by reacting active hydrogen-containing compounds with an amount of isocyanate in excess of the active hydrogen functionality present in the reaction mixture. The isocyanate functionality can be present in an amount of from about 0.2 wt. percent to about 40 wt. percent of the dispersion. A suitable prepolymer can ha
Guarriello John J.
Morris Terrel
The Dow Chemical Company
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