CARPET TILE PRIMARY BACKING SYSTEMS AND METHODS

Abstract

Tuftable nonwoven fabric compositions and methods for their preparation are provided. Fabric compositions may include a nonwoven web of continuous filaments, and an emulsion latex binder composition having an emulsion latex and a crosslinker. Exemplary techniques for constructing a nonwoven composition include forming continuous filaments of thermoplastic polymer, placing the filaments on a moving belt to form a nonwoven web, and treating the web with an emulsion latex binder composition having an emulsion latex and a crosslinker.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is related to U.S. patent application Ser. Nos. 11/434,944 and 11/438,732 filed May 16 and May 22, 2006, respectively. The entirety of each of these applications is incorporated herein by reference for all purposes.

BACKGROUND OF THE INVENTION

Embodiments of the present invention relate generally to methods of manufacturing nonwoven fabrics with emulsion latex binders, and in particular to methods of preparing primary carpet backing mats with binders that contain an emulsion latex and a crosslinker.

A tufted carpet is generally manufactured by inserting reciprocating needles threaded with a face yarn through a primary backing material to form loops or tufts of yarn in the backing. The quality, appearance, and dimensional stability of tufted carpets depends in large part on the properties of the primary backing.

Primary backings are usually produced from woven or nonwoven materials. Tufting into nonwoven materials is more difficult than tufting into woven materials. A woven fabric will open within the weave to accept the tufting needle and yarn and will then close around the tufted yarn after the needle has retracted. The closing property of woven fabrics provides a firm grip on the yarn in the opening. The yarn must remain in the opening until adhesive is applied to secure the yarn in place.

On the other hand, nonwovens have no weave to open and close nor do the individual filaments have a memory to return to the original state. Tufting into a nonwoven backing usually results in creating an opening large enough to accept the tufting needle and yarn. However, when the needle retracts, the opening does not close tightly around the yarn and remains larger than necessary to grip the yarn. The result is a condition in which the tufting yarn may slip out of the opening creating defects and necessitating repair and reworking.

Nonwoven backing materials typically are spunbonded or spunlaid webs formed from thermoplastic polymers such as polyolefins, polyesters and blends of these materials. Spunbonding is a process which generally involves feeding a thermoplastic polymer into an extruder, feeding the extruded molten polymer through a spinneret to form continuous filaments, stretching the continuous filaments, and laying down the stretched extruded filaments on a moving conveyor belt to form a nonwoven web of randomly arranged continuous filaments. In the stretching process, high velocity air can be directed toward the filaments via a ring mechanism having air jets. The high velocity air creates tension on the filaments, stretching them to 200× to 400× of their original length, thus making the filaments thinner and longer. In the lay-down process, desired orientation may be imparted to the filaments by various means such as rotation of the spinneret, electrical charges, introduction of controlled airstreams, varying the speed of the conveyor belt, and the like. The individual entangled filaments in the nonwoven web are then bonded primarily at filament cross-over points by thermal or chemical or mechanical treatments. The spunbonded web is then wound up in a roll form.

During the carpet tufting process, hundreds of tufting needles threaded with yarn are inserted into the primary backing material with each stroke of the needle bar. Each needle penetrates the backing material creating an opening and then retracts leaving a loop of yarn in each opening. Each needle then moves to the next insertion point. Hence, carpets are conventionally manufactured by tufting fibrous yarns into a primary backing mat using a needling operation. The fibrous yarns that undergo tufting may be in the form of a continuous yarn or as previously cut yarns. These yarns may be fed to a needle-punching machine for the tufting process. The characteristics of the primary backing mat fibers can determine how the tufted fibers are held in place by the primary backing mat. After the tufting process, the tufts may be susceptible to dislodgment from the primary backing. Latex adhesives can be used to prevent or inhibit the tufts from dislodgment. Rework may be necessary to insert any of the dislodged or absent tufts before the latex adhesive is applied.

During the tufting process, the primary backing material provides three very important characteristics: insertion resistance to the tufting needles, the ability to grip and hold the yarn loop (tuft) in place after the needles retract, and dimensional stability of the backing material during the tufting process. It is desirable to have a backing material which has minimal insertion resistance, maximum tuft grip at any point, and minimal extension under tension during the tufting process. However, mechanical and chemical properties of the web material can involve a designed trade-off among characteristics. That is to say, a high gripping force would likely involve a high penetration force and higher dimensional stability. Conversely, a low penetration force usually results in a poor or weak tuft gripping force and a higher degree of stretch under tension.

Despite recent significant and useful advances in the field of carpet primary backing technology, there continues to be a need for a primary backing that exhibits a relatively low insertion resistance, a high gripping force, and a low stretch or high dimensional stability. Embodiments of the present invention provide solutions to at least some of these needs.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the present invention encompass production methods for making a spunbond fabric that can be used as carpet tile primary backing. Exemplary products can include a spunbond fabric which is chemically bonded with a crosslinked emulsion latex binder system. The chemically bound spunbond provides enhanced strength and elasticity to attain the desired grip force for carpet tile backing application. Relatedly, carpet primary backing fabrics provided herein exhibit enhanced tufting and tuft securing characteristics.

Carpet can be manufactured by tufting carpet yarn through the interstices of the nonwoven backing mat. The needling operation can pass continuous or discontinuous staple yarn through the interstices of the backing mat, creating a carpet facing. The tufted yarns are held within the backing mat, and the carpet can be moved from a tufting station to an adhesive station that applies an adhesive latex layer on the underside of the tufted mat.

Frequently, after the tufting process, but before the latex adhesive has been applied, the tufts are susceptible to dislodgment from the primary backing. It is desirable to reduce or minimize the amount of rework required between these steps to reinsert any tufts that were dislodged before the latex adhesive is applied.

Advantageously, unique emulsion latex binder compositions can be used during the backing production process to achieve carpet backing materials having improved performance properties. For example, production methods may entail treating a nonwoven web with an emulsion latex binder composition that includes an emulsion latex and a crosslinker. Such treated nonwoven webs exhibit useful characteristic profiles that include low insertion resistance, high gripping force, and high dimensional stability.

In a first aspect, embodiments of the present invention encompass systems and methods for preparing a tuftable nonwoven fabric. Exemplary methods include loading a thermoplastic polymer into an extruder, heating the thermoplastic polymer within the extruder, extruding the heated thermoplastic polymer from the extruder, receiving the extruded heated thermoplastic polymer into a spinneret, forming a plurality of continuous filaments from the thermoplastic polymer with the spinneret, stretching the plurality of continuous filaments, receiving the plurality of stretched continuous filaments from the spinneret onto a moving belt to form a nonwoven web of continuous filaments, coating individual filaments of the nonwoven web with an emulsion latex binder composition having an emulsion latex and a crosslinker, drying and bonding the individual filaments of the nonwoven web, and heating the dried bonded individual filaments of the nonwoven web to complete the crosslinking reaction. In some cases, the crosslinker is present in the emulsion latex binder composition in an amount between about 0.05% and about 40% on a total weight basis of the binder composition weight. In some cases, the crosslinker is present in the emulsion latex binder composition in an amount between about 1% and about 25% on a total weight basis of the binder composition weight.

The emulsion latex component of the emulsion latex binder composition can include a polyurethane emulsion latex, a styrene butadiene rubber emulsion latex, an acrylic emulsion latex, an ethylene-vinyl chloride emulsion latex, a polyvinylidenechloride emulsion latex, a modified polyvinylchloride emulsion latex, a polyvinyl alcohol emulsion latex, an ethylene vinyl acetate emulsion latex, a polyvinyl acetate emulsion latex, an ethylacrylate-methylmethacrylate acrylic copolymer emulsion latex, a non-carboxylated acrylic with acrylonitrile copolymer emulsion latex, a carboxylated butyacrylic copolymer emulsion latex, a urea-formaldehyde emulsion latex, a melamine-formaldehyde emulsion latex, a polyvinylchloride-acrylic emulsion latex, a methylmethacrylate styrene copolymer emulsion latex, a styrene-acrylic copolymer emulsion latex, a phenol formaldehyde emulsion latex, a vinyl-acrylic emulsion latex, a polyacrylic acid emulsion latex, or the like, or mixtures thereof.

The crosslinker component of the emulsion latex binder composition can include a multifunctional aliphatic amine crosslinker, an organopolysiloxane crosslinker, a peroxide crosslinker, a urea-formaldehyde crosslinker, a melamine formaldehyde crosslinker, a phenol formaldehyde crosslinker, a multifunctional alcohol crosslinker, a multifunctional acid crosslinker, an acid derivative crosslinker, a multifunctional amine crosslinker, a multifunctional epoxy crosslinker, a multifunctional isocyanate crosslinker, a multifunctional capped isocyanate crosslinker, or the like, or mixtures thereof.

In some cases, the emulsion latex includes a polyurethane emulsion latex and the crosslinker includes a multifunctional aliphatic amine crosslinker that is present in the emulsion latex binder composition in an amount between about 0.05% and about 40% on a total weight basis of the binder composition weight. In some cases, the emulsion latex includes a polyurethane emulsion latex and the crosslinker includes a multifunctional aliphatic amine crosslinker that is present in the emulsion latex binder composition in an amount between about 1% and about 5% on a total weight basis of the binder composition weight. In some cases, the emulsion latex includes a styrene butadiene rubber emulsion latex and the crosslinker includes an organopolysiloxane crosslinker that is present in the emulsion latex binder composition in an amount between about 0.05% and about 40% on a total weight basis of the binder composition weight.

According to some embodiments, the emulsion latex includes a styrene butadiene rubber emulsion latex and the crosslinker includes an organopolysiloxane crosslinker that is present in the emulsion latex binder composition in an amount between about 10% and about 25% on a total weight basis of the binder composition weight. According to some embodiments, the emulsion latex includes an acrylic emulsion latex and the crosslinker includes a multifunctional aliphatic amine crosslinker that is present in the emulsion latex binder composition in an amount between about 0.05% and about 10% on a total weight basis of the binder composition weight. According to some embodiments, the emulsion latex includes an acrylic emulsion latex and the crosslinker includes a multifunctional aliphatic amine crosslinker that is present in the emulsion latex binder composition in an amount between about 1% and about 5% on a total weight basis of the binder composition weight.

Embodiments of the present invention encompass tuftable nonwoven fabrics and other spunbonds or materials prepared by any of the methods disclosed herein.

In another aspect, embodiments of the present invention encompass a tuftable nonwoven or spunbond fabric that includes a nonwoven web and an emulsion latex binder composition having an emulsion latex and a crosslinker. In some cases, the nonwoven web can include continuous or discontinuous filaments, or both. In some cases, the emulsion latex binder composition is present in the nonwoven web in an amount between about 2% and about 30% on a total weight basis of the combined emulsion latex binder composition and nonwoven web. In some cases, the emulsion latex binder composition is present in the nonwoven web in an amount between about 8% and about 25% on a total weight basis of the combined emulsion latex binder composition and nonwoven web. According to some embodiments, the nonwoven web exhibits a Quality Knee Force of greater than about 0.10 N and a Defect Peak Force of greater than about 0.35 N. According to some embodiments, the nonwoven web exhibits a Quality Knee Force of greater than about 0.10 N and a Defect Peak Force of greater than about 0.30 N. According to some embodiments, wherein the nonwoven web exhibits a Quality Knee Force of greater than about 0.05 N and a Defect Peak Force of greater than about 0.25 N. Optionally, a nonwoven web may exhibit a penetration resistance of less than about 65 N. In some cases, a 10 cm×2.54 cm piece of the nonwoven web may exhibit an elongation of less than about 15% under 16 lbf tension. In some instances, the elongation may be less than about 5% under 16 lbf tension.

In another aspect, embodiments of the present invention include coating individual filaments of a nonwoven web with an emulsion latex binder composition that includes an emulsion latex and a crosslinker, drying and bonding the individual filaments of the nonwoven web, and completing a crosslinking reaction in the emulsion latex binder composition that attaches the individual filaments of the nonwoven web via crosslinking.

Optionally, the crosslinking reaction can be facilitated or completed by heating the dried bonded individual filaments of the nonwoven web and the emulsion latex binder composition. In some cases, tuftable nonwovens may include an emulsion latex binder that is crosslinked by a crosslinker. In some cases, a tuftable nonwoven may include a physical blend containing a self crosslinked crosslinker and an emulsion latex binder. In some cases, a tuftable nonwoven may include a three dimensional network formed by a crosslinker that is crosslinked with both itself and an emulsion latex binder.

In still another aspect, embodiments of the present invention encompass methods for preparing a tuftable nonwoven fabric that include, for example, forming a nonwoven web of continuous filaments, coating individual filaments of the nonwoven web with an emulsion latex binder having an emulsion latex and a crosslinker, bonding the individual filaments of the nonwoven web, and heating the bonded individual filaments of the nonwoven web. In some cases, subsequent to heating the bonded individual filaments of the nonwoven web, the nonwoven web exhibits Quality Knee Force of greater than about 0.05 N, a Defect Peak Force of greater than about 0.25 N, and a penetration resistance of less than about 65 N, and wherein a 10 cm×2.54 cm piece of the nonwoven web exhibits an elongation of less than about 15% under 16 lbf tension.

For a fuller understanding of the nature and advantages of the present invention, reference should be had to the ensuing detailed description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides a schematic diagram depicting aspects of a carpet construction technique according to embodiments of the present invention.

FIG. 2 shows a schematic flowchart depicting aspects of a carpet construction technique according to embodiments of the present invention.

FIG. 3 provides a graphical representation of certain physical properties of carpet tile primary backings according to embodiments of the present invention.

FIG. 4 provides a graphical representation of certain physical properties of carpet tile primary backings according to embodiments of the present invention.

FIG. 5 provides a graphical representation of certain physical properties of carpet tile primary backings according to embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention encompass spunbonds and methods of their preparation that involve crosslinked binder systems. These techniques provide enhanced Quality Knee and Defect Peak values, or Tuft Grip parameters, while maintaining low Penetration Resistance and high dimensional stability.

Polyester or polyolefin spunbond can be manufactured by feeding a thermoplastic polymer into an extruder, feeding the extruded molten polymer through a spinneret to form continuous filaments, and laying down the extruded filaments on a moving conveyor belt to form a nonwoven web of randomly arranged continuous filaments. In the lay-down process, desired orientation can be imparted to the filaments by the rotation of the spinneret, introduction of controlled airstreams, or varying the speed of the conveyor belt. The individual entangled filaments in the nonwoven web can be bonded with an emulsion latex binder composition which can be dried and crosslinked in a heated oven.

Embodiments of the present invention provide emulsion latex binder compositions that include various emulsion latex and crosslinker combinations, for use in producing carpet primary backing materials. In some cases, the emulsion latex or emulsion latex component can include an acrylic latex, a styrene-butadiene rubber, an ethylene-vinyl chloride, a polyvinylidenechloride, a modified polyvinylchloride, a polyvinyl alcohol, an ethylene vinyl acetate, a polyvinyl acetate, an ethylacrylate-methylmethacrylate acrylic copolymer latex, a non-carboxylated acrylic with acrylonitrile copolymer latex, a carboxylated butyacrylic copolymer latex, a urea-formaldehyde latex, a melamine-formaldehyde latex, a polyvinylchloride-acrylic latex, a methylmethacrylate-styrene copolymer latex, a styrene-acrylic copolymer latex, a phenol-formaldehyde latex, a vinyl-acrylic latex, a polyacrylic acid latex, polyurethane, and the like. In some cases, the emulsion latex or emulsion latex component can include a mixture of two or more of the latexes described herein.

The crosslinker or crosslinker component can include a peroxide, a urea-formaldehyde, a melamine formaldehyde, a phenol formaldehyde, a multifunctional alcohols, a multifunctional acids or an acid derivative such as an ester and the like, a multifunctional amines, a multifunctional epoxy, a multifunctional isocyanate, a multifunctional capped isocyanate, an organopolysiloxane, and the like. In some cases, the crosslinker or crosslinker component can include a mixture of two or more of the crosslinkers described herein.

The amount of latex binder on the fabric can be between about 2% and about 30% on a total weight basis. In some cases, the amount of latex binder on the fabric can be between about 8% and about 25% on a total weight basis of the combined emulsion latex binder composition and fabric.

The amount of crosslinker in the binder formulation can be between about 0.05% and about 40% of the binder composition weight. In some cases, the amount of crosslinker in the binder formulation can be between about 1% and about 25% of the binder composition weight.

A first exemplary emulsion latex binder composition can include a latex binder component containing a polyurethane emulsion, and a crosslinker component containing a multifunctional aliphatic amine crosslinker. The polyurethane emulsion can be crosslinked with the multifunctional aliphatic amine crosslinker. The amount of aliphatic amine can be between about 0.05% and about 40% by weight of the binder composition. In some instances, the amount of aliphatic amine can be between about 1% and about 5% by weight of the binder composition.

A second exemplary emulsion latex binder composition can include a latex binder component containing a styrene-butadiene rubber (SBR) emulsion, and a crosslinker component containing an organopolysiloxane. Embodiments of the present invention encompass instances where the styrene-butadiene rubber emulsion can be crosslinked with the organopolysiloxane. Embodiments also encompass instances where the organosiloxane can self-crosslink and form a physical blend with SBR. As described elsewhere herein, physical blends can refer to combined materials that undergo little or no chemical structure change upon mixing. Hence, constituent parts of a physical blend typically do not react when added together. Further, embodiments encompass instances where the organosiloxane can crosslink with itself and an SBR emulsion to form a three dimensional crosslinked network. The amount of organopolysiloxane can be between about 0.05% and about 40% by weight of the binder composition. In some instances, the amount of organopolysiloxane can be between about 10% and about 25% by weight of the binder composition.

A third exemplary emulsion latex binder composition can include a latex binder component containing an acrylic emulsion, and a crosslinker component containing a multifunctional aliphatic amine crosslinker. The acrylic emulsion can be crosslinked with the multifunctional aliphatic amine crosslinker. The amount of aliphatic amine can be between about 0.05% and about 40% by weight of the binder composition. In some instances, the amount of aliphatic amine can be between about 1% and about 5% by weight of the binder composition.

Turning now to the drawings, FIG. 1 illustrates aspects of a process for forming a tuftable nonwoven fabric. As shown here, a nonwoven web or fabric 30 includes an arrangement or collection of continuous filaments 32 and an emulsion latex binder composition 34. Individual filaments 32 of the nonwoven web 30 can be attached with one another via components of the emulsion latex binder composition 34. The binder composition includes an emulsion latex and a crosslinker. In some instances, methods may include coating individual filaments of the nonwoven web with an emulsion latex binder composition, and subsequently completing a crosslinking reaction in the emulsion latex binder composition that attaches the individual filaments of the nonwoven web via crosslinking. For example, the crosslinking reaction can be completed or facilitated by heating the filaments of the nonwoven web and the emulsion latex binder composition. In some cases, the crosslinking reaction involves crosslinking the emulsion latex binder with the crosslinker. In some cases, the crosslinking reaction involves crosslinking the crosslinker, optionally to form a physical blend with the emulsion latex binder. For example, a physical blend can include a mixture of crosslinked crosslinker and emulsion latex binder, such that the crosslinked crosslinker and emulsion latex binder are blended together but do not react with each other. For example, the crosslinked crosslinker and the emulsion latex binder can be physically separable. In some cases, the crosslinker is self crosslinked while also being crosslinked with the emulsion latex binder, so as to form a three dimensional network.

With continued reference to FIG. 1, a needle 10 can penetrate into the nonwoven web 30 so as to insert the yarn tuft 20. The web 30 grips the yarn tuft 20 thus keeping it in place. In this way, embodiments provide a primary backing for a carpet that provides good gripping of the carpet fibers, after the primary backing is tufted with carpet yarn. The contact between the tufted yarn loop and the primary backing mat fiber provides a gripping strength that provides pull out resistance of the tufted carpet yarn. In some cases, the primary backing mat may be supplied as a roll for tufting of pile fibers to form a carpet. The primary backing mat may be made from a single polymeric composition or mixtures of polymeric compositions including weave patterns that use dissimilar yarns in the weaving process or use twisted or braided yarns of different polymeric compositions.

Hence, embodiments of the present invention provide a nonwoven backing mat 30 having individual mat fibers 32 that are entangled and bonded with an emulsion latex binder composition 34. In some cases, the binder composition can be applied by spraying it onto the nonwoven web. The sprayed or saturated nonwoven fabric can be supplied to a carpet tufting machine wherein carpet yarn is needled into openings or interstices between the primary backing mat fibers. Due to the treatment with the emulsion latex binder composition, a secure bond can be created between the tufted carpet yarn and the backing mat, thus providing a high pull out strength for the tufted carpet fibers. Hence, the carpet construction facilitates enhanced bonding of the tufted carpet yarns so that they are held securely in place.

Exemplary backing mat fiber materials can include nylon, polyester, polypropylene, jute, and the like. Exemplary carpet yarn fibers can include nylon, polyester, polypropylene, wool, and the like. Relatedly, the nonwoven material 30 may in some cases include a base material such as a spunlaid nonwoven polyester. The nonwoven material can be threaded through a binder composition dip tank containing the emulsion latex binder composition. In this way, the nonwoven material 30 can be partially or fully saturated with the binder composition. Individual filaments within the saturated nonwoven can then be bonded with the emulsion latex binder composition, dried, and heated in an oven to crosslink the emulsion latex binder composition. Suitable nonwoven webs include those prepared from thermoplastic polymers such as polyolefins, polyesters, polyamides, and blends of these polymers. Nonwovens may include spunbonded or spunlaid polyester webs.

FIG. 2 illustrates aspects of an exemplary method for preparing a tuftable nonwoven fabric or web. According to some embodiments, a process for forming a nonwoven web 200 can include loading a thermoplastic polymer into an extruder 210, heating the thermoplastic polymer within the extruder 220, extruding the heated thermoplastic polymer from the extruder 230, receiving the extruded heated thermoplastic polymer into a spinneret 240, forming a plurality of continuous filaments from the thermoplastic polymer with the spinneret 250, stretching the plurality of continuous filaments 255, receiving the plurality of stretched continuous filaments from the spinneret onto a moving belt to form a nonwoven web of continuous filaments 260, coating individual filaments of the nonwoven web with an emulsion latex binder composition having an emulsion latex and a crosslinker 270, drying and bonding individual filaments of the nonwoven web 280, and heating the dried bonded individual filaments of the nonwoven web to complete the crosslink reaction 290.

Exemplary nonwoven webs can include dry-laid, wet-laid, spunlaid, melt-blown, spunbonded, and spunlaced products. In some cases, the nonwoven web can be needled, heat-set, and calendered before treatment with an emulsion latex binder composition. Needling or needle-punching through the thickness of the nonwoven web can create fiber entanglement in the “Z” direction (i.e., through the thickness of the fabric) in addition to thermal bonding in the “X” and “Y” direction (i.e., in the machine direction and cross-machine direction). The needling can provide fiber bonding and entanglement in all directions, thereby increasing the opportunities for entanglement with the tufted yarn. Needling also provides additional loft to the fabric which results in a slightly thicker material for the same fabric weight and provides an additional grip on the tuft. The nonwoven web may be needled in one or both directions. Also, custom needling may be performed to create patterns or grains in the web. Needling (or needle-punching) can be performed using any commercially available needling apparatus. The degree of needling can affect the tensile strength of the web or fabric. The number of needle penetrations per square inch can be selected for optimum intermingling and entanglement of the individual filaments of the web. Optionally, fiber entanglement can be accomplished by hydro-entangling using high pressure water jets instead of barbed needles.

In some instances, the nonwoven web can be heat-set, which may improve dimensional stability and help lock in the loft provided by a needle-punching step. Improved loft can aid in reducing compression upon any subsequent calendering, and can also preshrink the web before locking in memory, thereby minimizing stretching or shrinking of the web which may occur during subsequent processing. Operable heat-setting temperatures can depend upon the nature of the polymer used to prepare the nonwoven web. For spunbonded or spunlaid polyester nonwovens, a temperature range of about 160 degrees C. to about 250 degrees C. can be used, for example. In some cases, a temperature range of about 180 degrees C. to about 190 degrees C. can be used. Any suitable heating apparatus, for example a drum oven, can be employed. Heat-setting can be accomplished by exposing the web to pressurized saturated steam or by employing apparatus which provides dry heat. The nonwoven web can be calendered after heat-setting by treating at temperatures and pressures sufficient to bond surface filaments and compact the web to a suitable thickness for further processing. Calendering may also be used to provide a smooth surface to the web, if desired. The temperature and pressure can be adjusted to provide a suitable thickness and surface texture to the web. Typically, when the web is previously heat-set, the loft is unaffected and internal fiber entanglement is undisturbed. The temperature and pressure conditions generally suitable for calendering range from about 100 degrees C. to about 250 degrees C. and from atmospheric up to about 500 lbs/in². Calender rolls or cylinders can be employed in the calendering process. The fabric can be cooled after calendering, for example to room temperature. Cooling can help set dimensional memory in the fabric. Cooling can be accomplished by air cooling or cooling jets or any cooling means.

Various techniques can be employed to apply the emulsion latex binder composition to the web. Bath immersion, spraying, or roller coating may be employed. In some cases, the nonwoven web is fully or partially saturated by the emulsion latex binder composition. This can be accomplished by immersing the web in a dip tank containing the emulsion latex binder composition and removing excess binder by feeding the web through a set of squeeze rollers. The fabric can be routed over drum heaters at a temperature high enough to dry the fabric and complete the crosslinking reaction. A range of suitable temperatures for either drying, curing, or both, is between about 100 degrees C. and about 250 degrees C.

The finished product can be wound up in rolls. In some cases, a winding apparatus is used which is designed to drive the take-up roll at the core. Friction wheel winders or core driven winders may also be used.

FIG. 3 provides a graph of the results of a Tuft Grip test for selected spunbond fabric constructions according to embodiments of the present invention. Tuft Grip force can be measured on a mimic test equipment as described in U.S. Pat. No. 7,475,601, the content of which is incorporated herein by reference, as the yarn gets pulled out of the spunbond fabric. According to some embodiments, the Tuft Grip force can be split into two segments, Quality Knee and Defect Peak. The initial resistance provided by the fabric or the primary backing against the movement of the yarn is typically an indicator of the quality of the tufting pattern and can be described as the Quality Knee. As shown here, the initial resistance can occur within the first 500 ms of a Tuft Grip force test. The peak resistance provided by the primary backing can be measured or characterized as the resistance against yarn loop pop-out during tufting, handling, and transportation of the tufted carpet before the application of the adhesive layer, and can be described as the Defect Peak. As shown here, a significant improvement, or increase, in both Quality Knee and Defect Peak is achieved with the crosslinked binder systems as compared with the standard binder system.

For example, incorporation of a binder without a crosslinker into a nonwoven web provides a Quality Knee of about 0.04N and a Defect Peak Force of about 0.18 N. Typically, a standard binder system includes and acrylic or SBR type of binder, at 18% on a total weight basis of the combined binder and nonwoven web. Further, the type of nonwoven filament in a standard binder system is typically PET Spunbond, and the type of yarn in a standard binder system is often Nylon yarn.

In contrast, incorporation of an emulsion latex binder composition having an acrylic emulsion latex and a multifunctional aliphatic amine crosslinker provides a Quality Knee Force of about 0.09 N and a Defect Peak Force of about 0.29 N. The amount of acrylic binder composition present on the fabric is about 18% on a total weight basis, and the amount of multifunctional aliphatic amine crosslinker present in the emulsion latex binder composition is about 5% by weight of the emulsion latex binder composition. The type of nonwoven filament is PET Spunbond and the type of yarn is Nylon yarn.

Similarly, incorporation of an emulsion latex binder composition having an SBR emulsion latex and a organopolysiloxane crosslinker provides a Quality Knee Force of about 0.14 N and a Defect Peak Force of about 0.32 N. The amount of binder composition present on the fabric is about 18% on a total weight basis, and the amount of organopolysiloxane crosslinker present in the emulsion latex binder composition is about 20% by weight of the emulsion latex binder composition. The type of nonwoven filament is PET Spunbond and the type of yarn is Nylon yarn.

Finally, incorporation of an emulsion latex binder composition having a polyurethane emulsion latex and a multifunctional aliphatic amine crosslinker provides a Quality Knee Force of about 0.13 N and a Defect Peak Force of about 0.37 N. The amount of binder composition present on the fabric is about 18% on a total weight basis, and the amount of multifunctional aliphatic amine crosslinker present in the emulsion latex binder composition is about 5% by weight of the emulsion latex binder composition. The type of nonwoven filament is PET Spunbond and the type of yarn is Nylon yarn.

FIG. 4 provides a graph of the results of a Penetration Resistance test for selected spunbond fabric constructions according to embodiments of the present invention. Penetration Resistance was measured on an Instron 3369 testing machine as the needles along with the yarn penetrate the fabric. As shown here, the Penetration Resistance of the primary backing with SBR and organosiloxane binder is comparable to the primary backing with uncrosslinked binder. The Penetration Resistance of the primary backings with aliphatic amine crosslinked binder systems is higher, but still within the operable limits of tufting machines (e.g. about 65 N to about 70 N). Hence, embodiments of the present invention provide enhanced Tuft Grip and dimensional stability, with little or no sacrifice in Penetration Resistance. The formulations discussed in FIG. 4 are equivalent to those described with reference to FIG. 3.

For example, incorporation of a binder without a crosslinker into a nonwoven web provides a maximum penetration resistance of about 35 N. In contrast, incorporation of an emulsion latex binder composition having a polyurethane emulsion latex and a multifunctional aliphatic amine crosslinker provides a maximum penetration resistance of about 51 N. Relatedly, incorporation of an emulsion latex binder composition having an SBR emulsion latex and a organopolysiloxane crosslinker provides a maximum penetration resistance of about 36 N. Finally, incorporation of an emulsion latex binder composition having an acrylic emulsion latex and a multifunctional aliphatic amine crosslinker provides a maximum penetration resistance of about 52 N.

FIG. 5 provides a graph of the results of a Dimensional Stability test for selected spunbond fabric constructions according to embodiments of the present invention. Percentage of elongation of a 10 cm×2.54 cm piece of fabric was measured on an Instron 3369 testing machine under 161bf tension. As shown here, a significant reduction in elongation is achieved with the crosslinked binder systems as compared with the standard binder system. The formulations discussed in FIG. 5 are equivalent to those described with reference to FIG. 3.

For example, incorporation of a binder without a crosslinker into a nonwoven web provides an elongation at 16 lbf tension of about 18%. In contrast, incorporation of an emulsion latex binder composition having a polyurethane emulsion latex and a multifunctional aliphatic amine crosslinker provides an elongation at 16 lbf tension of about 2%. Relatedly, incorporation of an emulsion latex binder composition having an SBR emulsion latex and a organopolysiloxane crosslinker provides an elongation at 16 lbf tension of about 4%. Finally, incorporation of an emulsion latex binder composition having an acrylic emulsion latex and a multifunctional aliphatic amine crosslinker provides an elongation at 16 lbf tension of about 2%. In sum, it can be seen that crosslinked binder systems showed a significantly lower percentage of elongation compared to uncrosslinked binder systems indicating a more dimensionally stable spunbond fabric or primary carpet backing.

Having described exemplary embodiments of the invention, by way of example and for clarity of understanding, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the present invention.

Claims

1. A method for preparing a tuftable nonwoven fabric, the method comprising:

loading a thermoplastic polymer into an extruder;

heating the thermoplastic polymer within the extruder;

extruding the heated thermoplastic polymer from the extruder;

receiving the extruded heated thermoplastic polymer into a spinneret;

forming a plurality of continuous filaments from the thermoplastic polymer with the spinneret;

stretching the plurality of continuous filaments;

receiving the plurality of stretched continuous filaments from the spinneret onto a moving belt to form a nonwoven web of continuous filaments;

coating individual filaments of the nonwoven web with an emulsion latex binder composition comprising an emulsion latex and a crosslinker;

drying and bonding the individual filaments of the nonwoven web; and

completing a crosslinking reaction in the emulsion latex binder composition that attaches the individual filaments of the nonwoven web via crosslinking by heating the dried bonded individual filaments of the nonwoven web and the emulsion latex binder composition.

2. The method of claim 1, wherein the crosslinker is present in the emulsion latex binder composition in an amount between about 0.05% and about 40% on a total weight basis of the binder composition weight.

3. The method of claim 1, wherein the crosslinker is present in the emulsion latex binder composition in an amount between about 1% and about 25% on a total weight basis of the binder composition weight.

4. The method of claim 1, wherein the emulsion latex comprises a member selected from the group consisting of a polyurethane emulsion latex, a styrene butadiene rubber emulsion latex, an acrylic emulsion latex, an ethylene-vinyl chloride emulsion latex, a polyvinylidenechloride emulsion latex, a modified polyvinylchloride emulsion latex, a polyvinyl alcohol emulsion latex, an ethylene vinyl acetate emulsion latex, a polyvinyl acetate emulsion latex, an ethylacrylate-methylmethacrylate acrylic copolymer emulsion latex, a non-carboxylated acrylic with acrylonitrile copolymer emulsion latex, a carboxylated butyacrylic copolymer emulsion latex, a urea-formaldehyde emulsion latex, a melamine-formaldehyde emulsion latex, a polyvinylchloride-acrylic emulsion latex, a methylmethacrylate styrene copolymer emulsion latex, a styrene-acrylic copolymer emulsion latex, a phenol formaldehyde emulsion latex, a vinyl-acrylic emulsion latex, and a polyacrylic acid emulsion latex.

5. The method of claim 1, wherein the crosslinker comprises a member selected from the group consisting of a multifunctional aliphatic amine crosslinker, an organopolysiloxane crosslinker, a peroxide crosslinker, a urea-formaldehyde crosslinker, a melamine formaldehyde crosslinker, a phenol formaldehyde crosslinker, a multifunctional alcohol crosslinker, a multifunctional acid crosslinker, an acid derivative crosslinker, a multifunctional amine crosslinker, a multifunctional epoxy crosslinker, a multifunctional isocyanate crosslinker, and a multifunctional capped isocyanate crosslinker.

6. The method of claim 1, wherein the emulsion latex comprises a polyurethane emulsion latex and the crosslinker comprises a multifunctional aliphatic amine crosslinker that is present in the emulsion latex binder composition in an amount between about 0.05% and about 40% on a total weight basis of the binder composition weight.

7. The method of claim 1, wherein the emulsion latex comprises a polyurethane emulsion latex and the crosslinker comprises a multifunctional aliphatic amine crosslinker that is present in the emulsion latex binder composition in an amount between about 1% and about 5% on a total weight basis of the binder composition weight.

8. The method of claim 1, wherein the emulsion latex comprises a styrene butadiene rubber emulsion latex and the crosslinker comprises an organopolysiloxane crosslinker that is present in the emulsion latex binder composition in an amount between about 0.05% and about 40% on a total weight basis of the binder composition weight.

9. The method of claim 1, wherein the emulsion latex comprises a styrene butadiene rubber emulsion latex and the crosslinker comprises an organopolysiloxane crosslinker that is present in the emulsion latex binder composition in an amount between about 10% and about 25% on a total weight basis of the binder composition weight.

10. The method of claim 1, wherein the emulsion latex comprises an acrylic emulsion latex and the crosslinker comprises a multifunctional aliphatic amine crosslinker that is present in the emulsion latex binder composition in an amount between about 0.05% and about 10% on a total weight basis of the binder composition weight.

11. The method of claim 1, wherein the emulsion latex comprises an acrylic emulsion latex and the crosslinker comprises a multifunctional aliphatic amine crosslinker that is present in the emulsion latex binder composition in an amount between about 1% and about 5% on a total weight basis of the binder composition weight.

12. A tuftable nonwoven fabric prepared by the method of claim 1.

13. A tuftable nonwoven, comprising:

a nonwoven web; and

an emulsion latex binder composition comprising an emulsion latex and a crosslinker.

14. The tuftable nonwoven fabric of claim 13, wherein the nonwoven web comprises a plurality of continuous or discontinuous filaments.

15. The tuftable nonwoven fabric of claim 13, wherein the emulsion latex binder composition is present in the nonwoven web in an amount between about 2% and about 30% on a total weight basis of the combined emulsion latex binder composition and nonwoven web.

16. The tuftable nonwoven fabric of claim 13, wherein the emulsion latex binder composition is present in the nonwoven web in an amount between about 8% and about 25% on a total weight basis of the combined emulsion latex binder composition and nonwoven web.

17. The tuftable nonwoven fabric of claim 13, wherein the emulsion latex binder is crosslinked by the crosslinker.

18. The tuftable nonwoven fabric of claim 13, wherein the crosslinker is self-crosslinked and forms a physical blend with the emulsion latex binder.

19. The tuftable nonwoven fabric of claim 13, wherein the crosslinker is self-crosslinked and crosslinked with the emulsion latex binder to form a three dimensional network.

20. The tuftable nonwoven fabric of claim 13, wherein the nonwoven web exhibits a Quality Knee Force of greater than about 0.10 N and a Defect Peak Force of greater than about 0.35 N.

21. The tuftable nonwoven fabric of claim 13, wherein the nonwoven web exhibits a Quality Knee Force of greater than about 0.10 N and a Defect Peak Force of greater than about 0.30 N.

22. The tuftable nonwoven fabric of claim 13, wherein the nonwoven web exhibits a Quality Knee Force of greater than about 0.05 N and a Defect Peak Force of greater than about 0.25 N.

23. The tuftable nonwoven fabric of claim 13, wherein the nonwoven web exhibits a penetration resistance of less than about 65 N.

24. The tuftable nonwoven fabric of claim 13, wherein a 10 cm×2.54 cm piece of the nonwoven web exhibits an elongation of less than about 15% under 16 lbf tension.

25. A method for preparing a tuftable nonwoven fabric, the method comprising:

forming a nonwoven web;

coating individual filaments of the nonwoven web with an emulsion latex binder comprising an emulsion latex and a crosslinker;

bonding the individual filaments of the nonwoven web; and

heating the bonded individual filaments of the nonwoven web;

wherein subsequent to heating the bonded individual filaments of the nonwoven web, the nonwoven web exhibits Quality Knee Force of greater than about 0.05 N, a Defect Peak Force of greater than about 0.25 N, and a penetration resistance of less than about 65 N, and wherein a 10 cm×2.54 cm piece of the nonwoven web exhibits an elongation of less than about 15% under 16 lbf tension.