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1. (WO2005061778) TEXTILE MULTICOUCHE ENDUIT D'ENVERS, SON PROCEDE DE FABRICATION ET SES UTILISATIONS
Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

MULTILAYER BACKCOATED TEXTILE, METHOD FOR MAKING IT AND USES

Field of the Invention
The invention relates to coating compositions. More specifically, the invention relates to coating compositions used as backcoatings for textiles.
Background of the Invention
Typically in the construction of durable woven fabric upholstery, an aqueous based polymeric backcoating is applied to the back side of a fabric to afford a variety of properties. These properties include hydrostatic resistance, fiber reinforcement, and an added avenue to incorporate flame retardant materials. The disadvantages that can arise from this process are typically the loss of pliability, which yields a somewhat stiff and boardy physical appearance that affects the tailorability and general perception of the fabric. Also, highly filled systems typically are undesirable due to chalking of filler or particulate components of the back coating through the textile to which it is applied, often referred to as opaque coating bleed through.
Backcoatings are often applied at levels between lA to several ounces per square yard ("oz/sq yd") via several blade and drying configurations. In order to achieve higher coating weights with proper drying and curing profiles, it is necessary to run multiple passes, depending on coating material, drying range length and available heating zones, as well as coating integrity. Prior art also teaches that to achieve greater pliability, it is necessary to apply a scrape coat (i.e. a very low coating weight), of the chosen polymeric coating, typically at a coating weight of from about lA to 1 oz/sq yd. In some cases, the coating composition is foamed to reduce the solids content of the coating composition by volume, thereby allowing a lower coating application weight to be applied in coating set-ups having minimum volumetric lay down requirements. Although this process is beneficial, many factors affect the success and reproducibility of the sought after end performance.
Summary of the Invention
Soft polymeric coatings have been used in the past to maintain good pliability of a backcoated textile substrate. Typically this soft polymer has been compounded with a variety of additives, such as clay, flame-retardant additives, rheology modifiers, plasticizers, and the like. Although this approach clearly allows for good flexibility, it becomes detrimental under elevated temperature situations, both with package and construction stability and with tailorability, because of the tacky characteristics associated with the physical state of the system. The coating(s)
t
may optionally be cross-linked to reduce tack, but the flexibility of the ultimate textile is sacrificed by crosslinking. Other options include increasing the inherent

Tg of the polymer, or polymer blends. However, as in the cross-linked system just discussed, pliability and flexibility of the textile will be diminished.
It has surprisingly been found in accordance with the present invention that backcoated textiles exhibiting exceptional performance may be produced by providing a textile having a plurality of backcoating layers. Specifically, the textile has a first coating layer comprising components selected to provide a tacky coating. This first coating layer is relatively soft. A second coating layer is additionally provided comprising components selected to provide a non-blocking coating. This second coating layer is relatively hard. The first coating layer is located between the textile and the second coating layer.
For purposes of the present invention, the first coating layer is considered to be tacky if it exhibits a Blocking Scale score of 4 or less in accordance with ASTM test 4946-89, Blocking of Architectural Coatings. Preferably, the first coating layer exhibits a Blocking Scale score of 3 or less, and more preferably exhibits a Blocking Scale score of 2 or less.
For purposes of the present invention, the second coating layer is considered to be a non-blocking coating layer if it exhibits a Blocking Scale score of 6 or more in accordance with ASTM test 4946-89, Blocking of Architectural Coatings.
Preferably, the second coating layer exhibits a Blocking Scale score of 7 or more, and more preferably exhibits a Blocking Scale score of 8 or more.
The backcoating system of the present invention provides textiles that exhibit exceptional hydrostatic and durability performance. Additionally, opaque bleed through and chalking may be substantially eliminated by the system of the present invention as well. Because the second coating does not block, the textiles of the present invention exhibit exceptional slip and tailorability characteristics.

Detailed Description
The term "hydrophobicity" as used herein means that the coating is water repellent and resists removal by washing. The term "oleophobicity" as used herein means that the coating is resistant to attack and removal by oils. The two terms may be combined herein with reference to the term "repellent." The term "stain resistant" as used herein means that the coating exhibits high stain release.
As used herein, the term "copolymer" encompasses both oligomeric and polymeric materials, and encompasses polymers incorporating two or more monomers. As used herein, the term "monomer" means a relatively low molecular weight material (i.e., generally having a molecular weight less than about 500

Daltons) having one or more polymerizable groups. "Oligomer" means a relatively intermediate sized molecule incorporating two or more monomers and generally having a molecular weight of from about 500 up to about 10,000 Daltons.
"Polymer" means a relatively large material comprising a substructure formed two or more monomeric, oligomeric, and/or polymeric constituents and generally having a molecular weight greater than about 10,000 Daltons.
As noted above, the first coating layer is a coating that is tacky in nature. This tackiness is determined by testing the coating in accordance with ASTM test 4946-89 to see if it exhibits a Blocking Scale score of 4 or less. Tackiness may be obtained in a number of ways apparent to the skilled artisan.
In a representative first technique to provide a tacky coating, a coating composition is formulated using polymeric materials having an unconventionally low average Tg for textile backcoating compositions. The low Tg of the polymer provides a coating as applied that is sufficiently tacky to result in the observed Blocking Scale score. Preferably, the polymers of the first coating layer composition have an average Tg of from about -30 to about 15° C.
In another representative technique to provide a tacky coating, the coating composition is formulated using polymers of an average Tg that is generally provided in backcoating compositions and that is below ambient temperature of expected use (such as below about 25° C), but with little or no filler or other component that may reduce tackiness of the coating layer, and with little or no crosslinking agent or functionality that would raise the effective Tg of the polymers in the coating composition. Preferably, the first layer comprises polymers of an average Tg of from about 15° C to about 25° C, and contains a sufficiently small amount of filler or other component to reduce tackiness of the coating layer, and has a sufficiently small amount of crosslinking agent or functionality that would raise the effective Tg of the polymers in the coating composition, so that the first coating layer exhibits a Blocking Scale score of 4 or less.
In yet another representative technique to provide a tacky coating, the coating composition may be formulated with polymers having any desired Tg, and additionally provided with tackifiers and/or plasticizers and/or other such materials that modify the behavior of the composition can be used alone or in a combination of two or more to reduce the effectively Tg of the polymer, thereby providing a tacky coating. Preferably, the first coating layer comprises polymers having an average Tg of greater than about 30° C, and additionally comprising tackifiers and/or plasticizers and/or other such materials that modify the behavior of the composition in an effective amount so that the first coating layer exhibits a Blocking Scale score of 4 or less.
Tackifiers, plasticizers and other such materials may be selected from any material as is now apparent to the skilled artisan. For example, tackifiers may be selected from natural resins of terpene based, rosin based, or a derivative thereof, and synthetic resins of aliphatic group based, aromatic group based, petroleum resin based, alkyl phenol based, xylene based, or coumarone indene based, or the like.
Combinations of the above techniques for providing a tacky coating layer, and additional techniques as may now be apparent to the skilled artisan, may be used to provide coatings of the desired tackiness.
The tacky coating layer is preferably provided at a coating weight of from about 0.1 to about 10 oz/sq yd, more preferably from about 0.1 to about 3 oz/sq yd, and most preferably from about 0.2 to about 1 oz/sq yd. In one embodiment, the tacky coating is present only on the upper surfaces of the textile fibers so that the second non-blocking coating is adhered to the textile through the first tacky coating material. Preferably, the tacky coating composition is provided in a continuous (i.e. uninterrupted) coating layer.

As noted above, the second layer is a coating that is non-blocking in nature. This tackiness is determined by testing the coating in accordance with ASTM test 4946-89 to see if it exhibits a Blocking Scale score of 6 or more. The non-blocking characteristic may be obtained in a number of ways apparent to the skilled artisan. In a representative first technique to provide a non-blocking coating, a coating composition is formulated using polymeric materials having a high average Tg for textile backcoating compositions. The high Tg of the polymer provides a coating as applied that possesses non-tacky characteristics so that the resulting coating layer exhibits the desired Blocking Scale score. Preferably, the polymers of the first coating layer composition have an average Tg of greater than about 30° C, and more preferably from about 35 to about 60° C.
In another representative technique to provide a non-blocking coating, the coating composition is formulated using polymers of an average Tg that is generally provided in backcoating compositions and that is below ambient temperature of expected use (such as below about 25° C), and additionally provided with filler or other component to reduce tackiness of the coating layer. Preferably, the non-blocking second coating layer comprises polymers having an average Tg below about 25° C, and additionally is provided with filler or other component to reduce tackiness of the coating layer in an effective amount so that the first coating layer exhibits a Blocking Scale score of 6 or more. Examples of such fillers include inert fillers such as clay, aluminum hydrate, silica, calcium carbonate, magnesium oxide, and the like. Additional functional component, such as flame retardant materials, may also act to reduce the tackiness of the ultimate coating to provide the desired non-blocking properties.
Examples of flame retardants include antimony oxide/decabrom
combinations and/or inherent flame retardant additives such as halogenated compounds and phosphate esters.
Preferably, the component to reduce the tackiness of the coating layer does not provide sites for attraction of soil or otherwise adversely affect other performance properties of the coated textile of the present invention. For example, the non-blocking coating layer preferably does not contain silicone components. It has surprisingly been found that silicone components, such as silicone polymers, when provided in a back coating composition may in certain embodiments migrate to the front surface of the textile. Silicone components, while often providing relatively short-lived water repellency, generally provide no resistance to oil based staining agents. Such components may render the textile much more difficult to clean than textiles not containing silicone components. The presence of such silicone components may even cause oil based stains to bond almost indelibly to the textiles containing such components. Preferably, silicone is not present in an amount that adversely affects resistance of the fabric to oils. Most preferably, the non-blocking coating composition is substantially free of silicone.
In yet another representative technique to provide a non-blocking coating, the coating composition is formulated using polymers of an average Tg that is generally provided in backcoating compositions and that is below ambient temperature of expected use (such as below about 25° C), and additionally provided with a crosslinking agent or functionality to raise the effective Tg of the polymers in the coating composition. Preferably, the non-blocking second coating layer comprises polymers having an average Tg below about 25° C, and additionally provided with additionally provided with a crosslinking agent or functionality to raise the effective Tg of the polymers in the coating composition to reduce tackiness of the coating layer in an effective amount so that the first coating layer exhibits a Blocking Scale score of 6 or more. Most preferably, the polymer of the coating composition is provided with functionalities that are reactive with crosslinking agents such as aziridine, a carbodimide, an epoxy, melamine-formaldehyde, or a polyisocyanate.
Combinations of the above techniques, and additional techniques as may now be apparent to the skilled artisan, may be used to provide coatings of the desired tackiness.
In a particularly preferred embodiment, the non-blocking coating layer may comprise unconventionally harder compounds or a greater amount of inert or active filler material as compared to conventional backcoating compositions. While not being bound by theory, it is believed that a harder second coat may be
accommodated without undesired stiffening due to the highly flexible first coating layer applied to the textile.

The non-blocking coating layer is preferably provided at a coating weight of from about 0.1 to about 10 oz/sq yd, more preferably from about 0.5 to about 8 oz/sq yd, and most preferably from about 1 to about 3 oz/sq yd. Preferably, the non-blocking coating composition is provided in a continuous (i.e. uninterrupted) coating layer. Heavier weight coatings generally provide superior hydrostatic properties, seam strength, and integrity of the textile as a barrier, e.g. in prevention of materials such as upholstery cushioning filler materials projecting through the textile.
Polymers to be used in either coating as described above may be selected from any appropriate chemistry as desired for compatibility with the particular use of the textile, provided that the coating meets the tackiness or non-blocking requirements as set forth above. Examples of suitable coating chemistries include film-forming polymers such as poly(urethane)s both of the poly(ether) and the poly(ester) form, poly(ester)s such as poly(ethylene terephthalate), flexible poly(vinyl)s, elastomeric poly(olefin)s such as poly(isoprene), poly(isobutylene), neoprene, butadiene rubber, low density poly(ethylene)s; (meth)acrylic polymers, acrylonitriles, styrene-butadiene polymers, and the like and combinations thereof. In a preferred embodiment, the polymer of the non-blocking second coating composition is an acrylonitrile polymer. Alternatively, in another embodiment, the polymer is an acrylonitrile/(meth)acrylate co-polymer emulsion. Most preferably, these polymers comprise about 35-50 percent acrylonitrile in the copolymer.
Particularly preferred such polymers include Rhoplex 1691 polymer, commercially available from Rohm & Hass; Hycar 1571 polymer from Noveon and MorFlo 155 polymer from OMNOVA Solutions Inc.
Preferred crosslinking agents include the melamine formaldehyde
crosslinking agents, such as Resimene 735 commercially available from Solutia Inc., St. Louis, MO. Alternative preferred crosslinking agents include the urea formaldehyde crosslinking agents, such as GP®2981 commercially available from Georgia-Pacific Corporation, Atlanta, GA. The polymer may, for example, comprise acid functionalities (such as carboxyl and sulfonyl) that may be
crosslinked with any appropriate crosslinking agent reactive with acid
functionalities. Preferred crosslinking agents include the tri-functional aziridines, such as Xama-7 commercially available from Bayer.

Narious other additives can be added to impart favorable end properties to the backcoating compositions. Such additives include rheology additives, wetting agents, defoamers, preservatives, colorants and the like.
Most preferably, the composition of the non-blocking coating layer is based upon conventional acrylic latices as are well known in the industry. A useful non-blocking second layer coating is Performax 3714, a proprietary acrylic formulation supplied by Νoveon (Ohio, USA).
A formulation for either the first tacky layer or the second non-blocking layer includes 45 to 50% film-forming acrylic water based emulsion; 22-27% filler, such as calcium carbonate; 10-12% thickener e.g., an alkali swellable material; 1-3% crosslinker, such as an urea formaldehyde; 0.5-1% defoamer; 1-2% surfactant and 1-2% amine, with the tack properties of the coating being determined by the Tg of the polymer.
The fabrics of the present invention may additionally be provided with treatments to enhance oleophobicity and/or hydrophobicity of the fabric. The fabrics preferably may be repellent in nature, and additionally may be stain resistant. In one embodiment of the present invention, these characteristics may be imparted by application of treatments in the form of layers on the fibers of the fabric. One or more of the same or different such treatment layers may be located either directly on the fibers with no intervening layer, between the first tacky back coating layer and the second non-blocking layer or on top of the non-blocking layer, or combinations thereof. Additionally, treatment layer may be provided primarily or exclusively on the opposite face of the textile from the backcoating system as described herein.
In a preferred embodiment of the present invention, a textile comprising a major front surface and a major back surface is provided. The entire textile is first treated with an oleophobic or hydrophobic treatment, followed by application of the tacky first coating layer to the back surface of the textile. The entire textile is then again treated with an oleophobic or hydrophobic treatment, followed by application of the non-blocking second coating layer to the back surface of the textile over the top of the first treatment, the first tacky coating layer, and the second treatment.

Most preferably, the first treatment layer is an oleophobic treatment, and the second treatment layer is a hydrophobic treatment. Examples of suitable treatment layers are described in commonly assigned U.S. Patent Application Serial No. 10/427,740 titled "Highly Durable, Coated Fabrics Exhibiting Hydrophobicity, Oleophobicity, and Related Methods" in the name of Sobieski et al.
In another preferred embodiment of the present invention, the textile is first coated with tacky first coating layer directly on the back surface of the textile.
Subsequently, the non-blocking second coating layer is coated directly to the first tacky coating layer. One or more fabric treatments as discussed above may then optionally be applied to the backcoated textile.
In yet another preferred embodiment of the present invention, the textile is first coated with one or more treatments as discussed above, and then coated with a tacky first coating layer on the back surface of the textile. Subsequently, the non-blocking second coating layer is coated directly to the first tacky coating layer. One or more fabric treatments as discussed above may then optionally be applied to the backcoated textile.
Non-limiting examples of suitable textile substrates for use according to this invention include materials made from natural and cellulosic fibers, such as cotton, flax, jute, ramie, sisal, rayon, acetate, and lyocell and synthetic fibers such as polyesters, nylons, acrylics, polyolefins, and spandex, and the like. A suitable fabric substrate may also consist of a blend of natural and synthetic fabric materials. In a particularly preferred embodiment of this invention, the fabric substrate is a polyester. Also preferred are fabric substrates comprising blends of polyesters and/or regenerated cellulose with cotton.
The textile may be a woven web, such as drill, scrim, cheese-cloth, and so forth, or a knit fabric. Various fabric types include, without limitation, broadcloth, jacquard, challis, corduroy, denim, duck, dobby weave, Leno weave, ottoman, oxford, poplin, rib weave, sailcloth, satin weave, shantung, and warp knit fabrics. Alternatively, the textile may be a nonwoven fabric. Nonwoven fabrics preferably are nonwoven cloths made standard web forming processes, such as wet laying processes, dry laying processes (including air laying with optional carding steps) and direct laid processes (including spun-bond, melt-blown and film fibrillation processes). Nonwoven fabrics may additionally be prepared by hydroentanglement processes, wherein a web of fibers is treated with jets of high pressure water or other liquid that serves to entangle the fibers. The water or liquid jets force the fibers into orientations where the fibers individually are at various angles with respect to each other and become physically entangled.
Coating compositions as described herein may be applied by any appropriate technique, such as by brush application, spraying, or casting by various techniques, such as doctor blade, gravure printing or other method of application. Preferably, the coating compositions are dried at desirably elevated temperatures such as from about 60 to about 250° C.
The coatings of this invention preferably have good resistance to moisture, good abrasion resistance, good chemical resistance, low coefficient of friction values, but yet remain flexible at low temperatures.
The invention will further be described by reference to the following nonlimiting examples.
EXAMPLES EXAMPLE 1
Sample 1A.
A 6 14 oz 100% polyester Jacquard fabric was provided with a first coating of 14 oz NovaCoat BFC-4 coating material from OMNOVA Solutions Inc. NovaCoat BFC-4 is a thermoplastic material that is a blend of two very low Tg materials having an effective Tg of-30°C, that further contains associated fillers and additives. To this first coating layer is applied a second coating that is a 2 14 oz coating of Perfoπnax 3714 from Noveon, Inc. Performax 3714 is a proprietary blend of acrylics, the first acrylic containing n-methanlol acrylamide as a
condensable cross-linking agent, and the other acrylic containing an acrylonitrile based acrylic emulsion.
Sample IB (comparative).
A 6 14 oz 100%o polyester Jacquard fabric was provided with a single coating of 3 oz NovaCoat BFC-4 coating material from OMNOVA Solutions Inc.
The hydrostatic performance of these samples was evaluated using a Souter hydrostatic test apparatus, and is presented in Table 1.



EXAMPLE 2
Static and kinetic coefficients of friction were evaluated on identical fabric substrates having different back coating materials applied thereto. A 100% cotton woven substrate was chosen for all the applications due to its high hydroscopic nature, which makes it the most difficult fabric substrate to treat and maintain pliability.
Sample 2A.
A cotton fabric substrate was coated with OMNOVA' s NovaCoat BFC-4 to form a continuous coating.
Sample 2B.
A cotton fabric substrate was coated with OMNOVA' s NovaCoat BFC-4 to form a coating having a coating weight of about 14 oz/sq. yard. A second coating composition of Noveon's Performax 3714 was applied to this first coating layer at a coating weight of about 2-1/2 oz/sq.yard. The most substantial difference in the two coating materials is that the second layer comprises a higher filler content, fire retardant content, and contains cross-linkable melamine formaldehyde, which increases film strength and Tg, but greatly reduces pliability in woven fabric substrates.
Tests to evaluate the coefficients of friction of these two samples were performed as described in ASTM D 1894-87, Static and Kinetic Coefficients of Friction of Plastic Film and Sheeting and Instron's Series IX Automated Materials Testing System 6.05, where the coefficients of friction were analyzed using a foam sled to fabric coating side, fabric coating sled to fabric coating side, and glass sled to fabric coating side. Results of these tests are presented in Tables 2-4.

Table 2.
Foam Sled to Coating
Sample A Sample B
Specimen Kinetic Static Specimen Kinetic Static
# COF COF # COF COF
1 .5822 1.1260 1 .9147 .9412
2 .5928 1.0610 2 .8565 , 1.0200
3 .5765 .9278 3 .9081 1.0520
4 .5975 1.2120 4 .8948 .9364
5 .5988 1.0920 5 .8865 .9852

Mean .5896 1.0840 Mean .8921 .9871
Std Dev. .0098 .10370 Std Dev. .0228 .0500

Table 3
Coatin Sled to Coatin


Table 4
Glass Sled to Coatin


EXAMPLE 3
An additional series of tests were performed using the same samples as described in Example 2 above, using ASTM 4946-89, Blocking of Architectural coatings. Here, the samples were cut into 3.8cm X 3.8cm specimens and placed coating face to coating face into an oven at 50° C. A 1-Kg weight was placed atop of each sample for the period of 30 minutes, removed and equilibrated at room temperature for an additional 30 minutes, and pulled apart. The degree of tack was evaluated and assigned a numerical value using the Scale as set forth in Table 3.

Table 5 - Blocking Scale



The degree of tack or blocking of these samples is reported in Table 6, below.
Table 6 - Results

Sample A 4 Sample B

EXAMPLE 4
The last set of experiments were conducted on what has been described as Sample 2B and a third sample, Sample 4C comprising the same cotton fabric substrate that is completely coated with harder Noveon, Performax 3714 material. Specifically, the fabric substrate was first coated with a 14 oz/sq.yard coating weight layer of Performax 3714 material, and then again coated with an additional 2-1/2 of Performax 3714 material.
The samples were conditioned at 50% relative humidity / ambient temperature, and run to the specifications of the instrument, " Digital Handle-O-Meter" model #211-5, in both the machine and cross machine direction. Results of this analysis are reported in Table 7.

Table 7


The data demonstrates that greater pliability (i.e. better "hand") was obtained in samples comprising a first tacky coating and a second non-blocking coating as compared to samples having only the second non-blocking coating at the same overall coating weight.
Preferably, textiles coated with a first tacky coating and a second non- blocking coating as presently described exhibit average Handle-o-meter data values that are less than 75% of the average Handle-o-meter data values exhibited by identical textiles having only non-blocking coatings at the same overall coating weight.
All percentages and ratios used herein are weight percentages and ratios unless otherwise indicated. All publications, patents and patent documents cited are fully incorporated by reference herein, as though individually incorporated by reference. Numerous characteristics and advantages of the invention meant to be described by this document have been set forth in the foregoing description. It is to be understood, however, that while particular forms or embodiments of the invention have been illustrated, various modifications, including modifications to shape, and arrangement of parts, and the like, can be made without departing from the spirit and scope of the invention.