Carpets and Textile Layers Comprising a Polymer Blend and Methods of Making the Same

Abstract

Provided are carpets and textile layers comprising a plurality of fibers and layer for locking the plurality of fibers, and methods for making them.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Patent Application No. 61/919,852, filed Dec. 23, 2013, the disclosure of which is incorporated herein by reference.

This application is related to (i) U.S. patent application Ser. No. 13/933,956, filed Jul. 2, 2013, which claims priority to U.S. Provisional Application No. 61/669,842, filed Jul. 10, 2012; (ii) PCT Application No. PCT/US2014/043150, filed Jun. 19, 2014, which claims priority to U.S. Provisional Application No. 61/842,231, filed Jul. 2, 2013; (iii) PCT Application No. PCT/US2014/059250, filed Oct. 6, 2014, which claims priority to U.S. Provisional Application No. 61/892,826, filed Oct. 18, 2013; and (iv) U.S. application Ser. No. 14/510,152, filed Oct. 9, 2014, which claims priority to U.S. Provisional Application No. 61/892,813, filed Oct. 18, 2013; the contents of each of which are incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to carpets and textile layers comprising a blend of propylene-based polymers, and methods of making such carpets and textile layers.

BACKGROUND OF THE INVENTION

In fiber-based flooring and wall-covering applications (such as rugs, carpets, heavy layer mats, automotive liners), a system is used to affix individual outward-facing fibers or fiber bundles to a backing structure. Depending on the intended use and carpet structure, certain fiber types and levels of adhesion of fibers to the backing structure are sought.

Most conventional carpets contain a primary backing layer, typically with fiber tufts in the form of cut or uncut loops extending upwardly from the backing to form a pile surface. In the case of tufted carpets, the fibers are generally tufted into a primary backing layer, with a secondary backing layer applied thereto. Additional backing layers can be optionally attached to the secondary backing layer.

A precoat layer is typically applied to the back side of the primary backing layer to affix the yarn to the primary backing layer. The precoat layer may substantially penetrate the yarn (fiber bundle) exposed on the backside of the primary backing layer and may substantially consolidate individual fibers within the yarn. Known precoat materials include latex, urethane, and vinyl systems, with latex systems being particularly commonly used. Styrene butadiene rubbers (SBR) and vinyl acetate ethylene (VAE) are common polymers used for latex adhesive backing materials. Typically, the latex backing system is heavily filled with an inorganic filler such as calcium carbonate or aluminum trihydrate, and includes other ingredients such as antioxidants, antimicrobials, flame retardants, smoke suppressants, wetting agents, and froth aids.

Latex is one of the incumbent methods for adhering carpet fibers to the backing layer (e.g., via a precoat layer). During the production process, the latex impregnates the fiber bundles, and after drying of the latex, the fibers are affixed to the structure. However, the use of latex has a number of disadvantages. For one, the material needs to be applied to fibers in a low viscous state in order to impregnate deep into fiber structure. After impregnation, the excess water typically needs to be removed in-line by a drying process. This process involves substantial energy use and production line length. Also, latex is non-thermoplastic, which is not desirable in cases where the carpets are to be recycled. This is particularly the case if the rest of the carpet construction is thermoplastic in nature. In addition, latex often has a typical odor that can linger for a long time after a new carpet is installed.

Traditional polymer systems often have too high viscosity to penetrate into the substrate (e.g., woven material) and affix the fibers. Use of these traditional polymer systems often requires compounding to reduce the viscosity, and the resulting compounds often have limited cohesion. It is sometimes preferred to have carpet backing compositions with a high flow rate or low viscosity in order facilitate the composition's flow around the tufted carpet fibers to form a secure bond between the carpet fibers, the primary backing layer and the second backing layer. One way to increase flowablity of a carpet backing composition is to include a polymer component having a higher melt flow rate (MFR). However, certain such polymer components may have low molecular weight and low melt strength, which may result in breakage of the extruded sheet of the molten or semi-molten carpet backing composition during continuous extrusion.

Thus, there is a need for a carpet backing systems that can provide good adhesion between the fibers and the backing layer (such as by incorporating a high flow rate or low viscosity composition), preferably without the need to incorporate latex. The same applies also in textile applications for adhering fibers or improving structural integrity in uses such as mattresses and upholstery (e.g., sofa, chair covers).

U.S. Patent Publication Nos. 2007/095453 A1, 2008/0280093 A1, and 2011/0256335 A1 disclose a carpet and method of making it. The carpet includes (a) a primary backing which has a face and a back surface, (b) a plurality of fibers attached to the primary backing and extending from the face of the primary backing and exposed at the back surface of the primary backing, (c) an adhesive backing, (d) an optional secondary backing adjacent to the adhesive backing, and (e) at least one homogeneously branched linear ethylene polymer.

U.S. Patent Application Publication No. 2014/0017439 describes carpets comprising a propylene-based copolymer, and method of making the same. The presence of the propylene-based copolymer is said to provide the carpet with improved properties, including good tuft bind strength and tuft lock strength, and reliable construction.

U.S. Pat. No. 7,741,397 describes a filled polymer composition comprising (i) an ethylene/α-olefin interpolymer, and (ii) a filler. The ethylene/α-olefin interpolymer is a block copolymer. The filled polymer composition can be used in automotive floorings, roofings, wire and cable coating applications.

U.S. Patent Publication Nos. 2007/0095453 and 2008/0280093 relate to carpets and method of making carpets. The carpet includes (a) a primary backing which has a face and a back surface, (b) a plurality of fibers attached to the primary backing and extending from the face of the primary backing and exposed at the back surface of the primary backing, (c) an adhesive backing, (d) an optional secondary backing adjacent to the adhesive backing, and (e) at least one homogeneously branched linear ethylene polymer. The method includes extrusion coating at least one homogeneously branched linear ethylene polymer onto the back surface of a primary backing to provide an adhesive backing.

Polymer compositions and methods of making polymer compositions for adhesive applications are disclosed in U.S. Pat. Nos. 7,294,681 and 7,524,910. Various polymers described in these patents and/or produced by the methods disclosed in these patents have been sold by ExxonMobil Chemical Company as LINXAR™ polymers.

WO Publication No. 2013/134038 discloses a method for producing a polymer blend having at least two different propylene-based polymers produced in parallel reactors. The multi-modal polymer blend has a Mw of about 10,000 g/mol to about 150,000 g/mol. When subjected to Temperature Rising Elution Fractionation, the polymer blend exhibits a first fraction that is soluble at −15° C. in xylene, the first fraction having an isotactic (mm) triad tacticity of about 70 mol % to about 90 mol %; and a second fraction that is insoluble or less soluble than the first fraction at −15° C. in xylene, the second fraction having an isotactic (mm) triad tacticity of about 85 mol % to about 98 mol %.

There is a need for fiber-based flooring, wall-covering, and textile applications that can provide good adhesion between the fibers and the backing layer, preferably without the need to incorporate latex. Applicants have found that this can be achieved with an adhesion layer containing a blend of propylene-based polymers. In particular, such a polymer blend has lower viscosity and provides good penetration and bonding of the fibers to the structure. In some embodiments, an adhesion layer containing such a blend can act as a substitute for a precoat layer, such as a latex precoat layer.

SUMMARY OF THE INVENTION

Provided are carpets and textile layers comprising a blend of propylene-based polymers, and methods of making the same.

Provided herein are carpets and textile layers, such as textile layers for use in upholstery or mattress applications, comprising: (a) a plurality of fibers; and (b) an adhesion layer for locking the plurality of fibers, wherein the adhesion layer comprises a polymer blend containing: (i) a first propylene-based polymer, wherein the first propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C₄ to C₁₀ alpha-olefin; and (ii) a second propylene-based polymer, wherein the second propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C₄ to C₁₀ alpha-olefin, wherein the second propylene-based polymer is different than the first propylene-based polymer.

Also provided herein are carpets comprising: (a) a primary backing layer having a face side and a back side; (b) a plurality of fibers attached to the primary backing layer and extending from both the face side and the back side of the primary backing layer; and (c) a second layer attached to the back side of the primary backing layer, wherein at least one of the primary backing layer and the second layer comprises a polymer blend comprising: (i) a first propylene-based polymer, wherein the first propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C₄ to C₁₀ alpha-olefin; (ii) a second propylene-based polymer, wherein the second propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C₄ to C₁₀ alpha-olefin, wherein the second propylene-based polymer is different than the first propylene-based polymer.

Also provided herein are methods for making a carpet or a textile layer, comprising the steps of: (a) providing a plurality of fibers, and (b) applying a melt comprising a polymer blend to the plurality of fibers to form an adhesion layer for locking the plurality of fibers, wherein the polymer blend comprises: (i) a first propylene-based polymer, wherein the first propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C₄ to C₁₀ alpha-olefin: (ii) a second propylene-based polymer, wherein the second propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C₄ to C₁₀ alpha-olefin, wherein the second propylene-based polymer is different than the first propylene-based polymer, and (c) forming a carpet or a textile layer.

In the carpet or textile layer, the adhesion layer may be continuous or discontinuous. In some embodiments, the adhesion layer substantially locks in the plurality of fibers.

The polymer blend may have a melt viscosity, measured at 190° C. according to ASTM D-3236, of about 500 to about 25,000 cP, preferably about 1.000 to about 10.000 cP. The polymer blend may have a weight average molecular weight of from about 28,000 to about 48,000 g/mol. The polymer blend may have a melt flow rate of from greater than about 1,000 g/10 min, or greater than about 1,500 g/10 min.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary structure for a tufted carpet tile containing an adhesion layer for locking in a plurality of fibers.

FIG. 2 illustrates an exemplary structure for a tufted carpet tile containing a primary backing and a second layer for locking in a plurality of fibers. Either or both of the primary backing and a second layer can be an adhesion layer according to the invention.

FIGS. 3 (a) and (b) illustrates an exemplary textile layer containing a discontinuous adhesion layer for locking in a plurality of fibers.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

Various specific embodiments of the invention are described, including preferred embodiments and definitions adopted herein. While the following detailed description gives specific preferred embodiments, those skilled in the art will appreciate that these embodiments are exemplary only, and that the invention can be practiced in other variations. Any reference to the “invention” may refer to one or more, but not necessarily all, of the inventions defined by the claims. The use of headings is for purposes of convenience only and does not limit the scope of the invention.

As used herein, when a polymer composition or blend is said to comprise a certain percentage, wt %, of a monomer, that percentage of monomer is based on the total amount of monomer units of all the polymer components of the polymer composition or blend.

As used herein, “elastomer” or “elastomeric composition” refers to any polymer or composition of polymers (such as blends of polymers) consistent with the ASTM D1566 definition. Elastomer includes mixed blends of polymers such as melt mixing and/or reactor blends of polymers. The terms may be used interchangeably with the term “rubber(s).”

A “polyolefin” is a polymer comprising at least 50 wt % of one or more olefin monomers. Preferably, a polyolefin comprises at least 60 wt %, or at least 70 wt %, or at least 80 wt %, or at least 90 wt %, or at least 95 wt %, or 100 wt %, of one or more olefin monomers. Preferably, a polyolefin comprises 1-olefins, having carbon numbers of 2 to 20, or 2 to 16, or 2 to 10, or 2 to 8, or 2 to 6.

As used herein, “primary backing” layer, “second” layer, “third” layer, and “middle” layer are merely identifiers used for convenience, and shall not be construed as limitation on individual layers, their relative positions, or the laminated structure, unless otherwise specified.

As used herein, when a layer is said to be “for locking the plurality of fibers.” such layer can be in direct contact and directly adhered to the plurality of fibers (e.g., as an immediately underlying layer), or in indirect contact (e.g., via an intermediate layer between the referenced layer and the plurality of fibers). When a layer is referred to as “substantially” locking the plurality of fibers, it means that at least about 90% (preferably at least about 92%, at least about 94%, at least about 96%, or at least about 98%) of the fibers are held in place after being rolled over by a Velcro type tool for about 20 times in a Velcro roller test. Preferably, no fuzzing is visible to the naked eye.

As used herein, “carpet” also includes carpet tiles, portions of a carpet, and mats such as heavy layer mats.

As used herein, a “textile layer” is any layer made of a textile material.

Described herein are carpets and textile layers comprising a blend of two propylene-based polymers, and methods of making the same. In some embodiments, such carpets or textile layers comprise: (a) a plurality of fibers; and (b) an adhesion layer for locking the plurality of fibers, wherein the adhesion layer comprises a polymer blend as described herein.

Polymer Blend

The polymer blend contains: (i) a first propylene-based polymer, wherein the first propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C₄ to C₁₀ alpha-olefin; and (ii) a second propylene-based polymer, wherein the second propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C₄ to C₁₀ alpha-olefin, wherein the second propylene-based polymer is different than the first propylene-based polymer.

The polymer blend has a melt viscosity, measured at 190° C. according to ASTM D-3236, of at least 500 cP, or at least 700 cP, or at least 900 cP, or at least 1000 cP. The polymer blend may have a melt viscosity of less than 30,000 cP, or less than 25.000 cP, or less than 20,000 cP, or less than 15,000 cP, or less than 10,000 cP, or less than 9000 cP, or less than 8000 cP, or less than 7000 cP. In some embodiments, the polymer blend may have a melt viscosity of from about 500 to about 25,000 cP, or from about 1,000 to about 10,000 cP, or from about 900 to about 20,000 cP.

The polymer blend may, when subjected to Temperature Rising Elution Fractionation, exhibit: a first fraction that is soluble at −15° C. in xylene, the first fraction having an isotactic (mm) triad tacticity of about 70 mol % to about 90 mol %; and a second fraction that is insoluble at −15° C. in xylene, the second fraction having an isotactic (mm) triad tacticity of about 85 mol % to about 98 mol %.

The polymer blend may have a weight average molecular weight (Mw) of at least 10,000 g/mol, or at least 15,000 g/mol, or at least 20,000 g/mol, or at least 25.000 g/mol, or at least about 28,000 g/mol. The polymer blend may have a Mw of less than 100,000 g/mol, or less than 90,000 g/mol, or less than 80,000 g/mol, or less than 70.000 g/mol, or less than 60,000 g/mol, or less than 50,000 g/mol, or less than about 48,000 g/mol. In some o embodiments, the polymer blend may have a Mw of from 10,000 to 100,000 g/mol, or from 15,000 to 80,000 g/mol, or from 20,000 to 70,000 g/mol, or from 25,000 to 60,000 g/mol, or from 25,000 to 50,000 g/mol, or from about 28,000 to about 48,000 g/mol.

The polymer blend may have a melt flow rate of at least 100 g/10 min, or at least 300 g/10 min, or at least 500 g/10 min, or at least 700 g/10 min, or at least 1000 g/10 min, or at least 1,200 g/10 min, or at least 1,300 g/10 min, or at least 1,400 g/10 min, or at least about 1,500 g/10 min. In some embodiments, the polymer blend may have a melt flow rate of less than 20,000 g/10 min, ore less than 10,000 g/10 min, or less than 7,500 g/10 min.

The polymer blend may have a Shore C hardness of at least 5, or at least 7, or at least 8, or at least 9, or at least 10, or at least 11, or at least 12, or at least 13, or at least 14, or at least 15. The polymer blend may have a Shore C Hardness of less than 100, or less than 75, or less than 70, or less than 65, or less than 60, or less than 55, or less than 50, or less than 45, or less than 40, or less than 35, or less than 30.

The polymer blend may have an ethylene content of at least 2 wt %, or at least 3 wt %, or at least 4 wt %, or at least 5 wt %. The polymer blend may have an ethylene content of less than 25 wt %, or less than 20 wt %, or less than 19 wt %, or less than 18 wt %, or less than 17 wt %, or less than 16 wt %, or less than 15 wt %, or less than 14 wt %, or less than 13 wt %.

The polymer blend may have a heat of fusion of less than 90 J/g, or less than 80 J/g, or less than 75 J/g, or less than 70 J/g, or less than 65 J/g, or less than 60 J/g, or less than 60 J/g, or less than 55 J/g, or less than 50 J/g, or less than 45 J/g, or less than 40 J/g. The polymer blend may have a heat of fusion of at least 5 J/g, or at least 7 J/g, or least 10 J/g, or at least 12 J/g, or at least 15 J/g, or at least 20 J/g.

In some embodiments, the polymer blend meets at least one of the following: (i) the polymer blend comprises at least about 70 mol % of propylene-derived units; (ii) the polymer blend has a heat of fusion of between about 10 to about 90 J/g; (iii) the first propylene-based polymer and the second propylene-based polymer each comprises a copolymer of propylene and ethylene; and (iv) the first propylene-based polymer and the second propylene-based propylene polymer have a difference in heat of fusion of at least 10 J/g. In some embodiments, the polymer blend may meet at least two, or at least three, or may meet all four of the above described properties.

In a preferred embodiment, the polymer blend may have at least one of the following properties, and in any combination of the viscosity, DSC crystallinity, shore hardness, ethylene content, and/or melting point values set forth in Table 1 below. The polymer blend may also be bi-modal. The term “bi-modal” as used herein refers to polymers or polymer blends having more than one compositional peak when measured by GPC, DSC, or TREF.

TABLE 1
Viscosity	DSC
at 190° C.,	Crystallinity,	Shore	Ethylene	DSC Melting
cP	dH J/g	Hardness C	Content, %	Point, ° C.
900-20,000	15-50	10-55	3-20	40-115
900-15,000	20-40	15-30	5-17	50-115; or
				100-130

Polymers in the Polymer Blend

The term “polymer” as used herein includes, but is not limited to, homopolymers, copolymers, interpolymers, terpolymers, etc., and alloys and blends thereof. Further, as used herein, the term “copolymer” is meant to include polymers having two or more monomers, optionally with other monomers, and may refer to interpolymers, terpolymers, etc. The term “polymer” as used herein also includes impact, block, graft, random and alternating copolymers. The term “polymer” shall further include all possible geometrical configurations unless otherwise specifically stated. Such configurations may include isotactic, syndiotactic and random symmetries. The polymer blend of the invention includes, but is not limited to, a blend of one or more polymers prepared in solution or by physical blending, such as melt blending.

“Propylene-based” as used herein is meant to include any polymer comprising propylene, either alone or in combination with one or more comonomers, in which propylene is the major component (i.e., greater than 50 mol % propylene).

One or more polymers of the polymer blend may comprise one or more propylene-based polymers, which comprise propylene and from about 2 mol % to about 30 mol % of one or more comonomers selected from C₂ and C₄ to C₁₀ α-olefins. In some embodiments, the α-olefin comonomer units may derive from ethylene, butene, pentene, hexene, 4-methyl-1-pentene, octene, or decene. The embodiments described below are discussed with reference to ethylene and hexene as the α-olefin comonomer, but the embodiments are equally applicable to other copolymers with other α-olefin comonomers. In this regard, the copolymers may simply be referred to as propylene-based polymers with reference to ethylene or hexene as the α-olefin.

The one or more polymers of the polymer blend may include at least about 5 mol %, at least about 6 mol %, at least about 7 mol %, or at least about 8 mol %, or at least about 10 mol %, or at least about 12 mol % ethylene-derived or hexene-derived units. In these or other embodiments, the copolymers may include up to about 30 mol %, or up to about 25 mol %, or up to about 22 mol %, or up to about 20 mol %, or up to about 19 mol %, or up to about 18 mol %, or up to about 17 mol % ethylene-derived or hexene-derived units, where the percentage by mole is based upon the total moles of the propylene-derived and α-olefin derived units. Stated another way, the propylene-based polymer may include at least about 70 mol %, or at least about 75 mol %, or at least about 80 mol %, or at least about 81 mol % propylene-derived units, or at least about 82 mol % propylene-derived units, or at least about 83 mol % propylene-derived units; and in these or other embodiments, the copolymers may include up to about 95 mol %, or up to about 94 mol %, or up to about 93 mol %, or up to about 92 mol %, or up to about 90 mol %, or up to about 88 mol % propylene-derived units, where the percentage by mole is based upon the total moles of the propylene-derived and alpha-olefin derived units. In any embodiment, the propylene-based polymer may comprise from about 5 mol % to about 25 mol % ethylene-derived or hexene-derived units, or from about 8 mol % to about 20 mol % ethylene-derived or hexene-derived units, or from about 12 mol % to about 18 mol % ethylene-derived or hexene-derived units.

The one or more polymers of the polymer blend are characterized by a melting point (Tm), which can be determined by differential scanning calorimetry (DSC). For purposes herein, the maximum of the highest temperature peak is considered to be the melting point of the polymer. A “peak” in this context is defined as a change in the general slope of the DSC curve (heat flow versus temperature) from positive to negative, forming a maximum without a shift in the baseline where the DSC curve is plotted so that an endothermic reaction would be shown with a positive peak.

The Tm of the one or more polymers of the polymer blend (as determined by DSC) may be less than about 130° C., or less than about 120° C. or less than about 115° C. or less than about 110° C., or less than about 100° C., or less than about 90° C. In any embodiment, the Tm of the one or more polymers of the polymer blend may be greater than about 25° C., or greater than about 30° C., or greater than about 35° C., or greater than about 40° C.

The crystallization temperature (Tc) of the polymer (as determined by DSC) may be less than about 110° C., or less than about 90° C. or less than about 80° C., or less than about 70° C., or less than about 60° C. or less than about 50° C., or less than about 40° C., or less than about 30° C., or less than about 20° C. or less than about 10° C. In the same or other embodiments, the Tc of the polymer is greater than about 0° C., or greater than about 5° C., or greater than about 10° C., or greater than about 15° C., or greater than about 20° C. In any embodiment, the Tc lower limit of the polymer may be 0° C., 5° C., 10° C., 20° C., 30° C. 40° C., 50° C., 60° C., and 70° C.; and the Tc upper limit temperature may be 100° C., 90° C., 80° C., 70° C., 60° C., 50° C., 40° C., 30° C. 25° C., and 20° C. with ranges from any lower limit to any upper limit being contemplated.

The polymers suitable for use in the polymer blend are said to be “semi-crystalline”, meaning that in general they have a relatively low crystallinity. The term “crystalline” as used herein broadly characterizes those polymers that possess a high degree of both inter and intra molecular order, and which preferably melt higher than 110° C., more preferably higher than 115° C., and most preferably above 130° C. A polymer possessing a high inter and intra molecular order is said to have a “high” level of crystallinity, while a polymer possessing a low inter and intra molecular order is said to have a “low” level of crystallinity. Crystallinity of a polymer can be expressed quantitatively, e.g., in terms of percent crystallinity, usually with respect to some reference or benchmark crystallinity. As used herein, crystallinity is measured with respect to isotactic polypropylene homopolymer. Preferably, heat of fusion is used to determine crystallinity. Thus, for example, assuming the heat of fusion for a highly crystalline polypropylene homopolymer is 190 J/g, a semi-crystalline propylene copolymer having a heat of fusion of 95 J/g will have a crystallinity of 50%. The term “crystallizable” as used herein refers to those polymers which can crystallize upon stretching or annealing. Thus, in certain embodiments, the semi-crystalline polymer may be crystallizable. The semi-crystalline polymers used in the blends described herein preferably have a crystallinity of from 2% to 65% of the crystallinity of isotatic polypropylene. In further embodiments, the semi-crystalline polymers may have a crystallinity of from about 3% to about 40%, or from about 4% to about 30%, or from about 5% to about 25% of the crystallinity of isotactic polypropylene.

The polymers can have a level of isotacticity expressed as percentage of isotactic triads (three consecutive propylene units), as measured by ¹³C NMR, of 75 mol % or greater, 80 mol % or greater, 85 mol % or greater, 90 mol % or greater, 92 mol % or greater, 95 mol % or greater, or 97 mol % or greater. In one or more embodiments, the triad tacticity may range from about 75 mol % to about 99 mol %, or from about 80 mol % to about 99 mol %, or from about 85 mol % to about 99 mol %, or from about 90 mol % to about 99 mol %, or from about 90 mol % to about 97 mol %, or from about 80 mol % to about 97 mol %. Triad tacticity is determined by the methods described in U.S. Patent Application Publication No. 2004/0236042.

The polymers may have a tacticity index m/r ranging from a lower limit of 4, or 6 to an upper limit of 10, or 20, or 25. The tacticity index, expressed herein as “m/r”, is determined by ¹³C nuclear magnetic resonance (“NMR”). The tacticity index m/r is calculated as defined by H. N. Cheng in 17 MACROMOLECULES, 1950 (1984), incorporated herein by reference. The designation “m” or “r” describes the stereochemistry of pairs of contiguous propylene groups, “m” referring to meso and “r” to racemic. An m/r ratio of 1.0 generally describes an atactic polymer, and as the m/r ratio approaches zero, the polymer is increasingly more syndiotactic. The polymer is increasingly isotactic as the m/r ratio increases above 1.0 and approaches infinity.

The polymers may have a density of from about 0.85 g/cm³ to about 0.92 g/cm³, or from about 0.86 g/cm³ to about 0.90 g/cm³, or from about 0.86 g/cm³ to about 0.89 g/cm³ at room temperature and determined according to ASTM D-792.

The polymers can have a weight average molecular weight (Mw) of from about 5,000 to about 500.000 g/mol, or from about 7,500 to about 300,000 g/mol, or from about 10,000 to about 200,000 g/mol, or from about 25,000 to about 175,000 g/mol.

Weight-average molecular weight, M_w, molecular weight distribution (MWD) or M_w/M_n where M_n is the number-average molecular weight, and the branching index, g′(vis), are characterized using a High Temperature Size Exclusion Chromatograph (SEC), equipped with a differential refractive index detector (DRI), an online light scattering detector (LS), and a viscometer. Experimental details not shown below, including how the detectors are calibrated, are described in T. Sun, P. Brant, R. R. Chance, and W. W. Graessley, Macromolecules, Volume 34, Number 19, pp. 6812-6820, 2001.

Solvent for the SEC experiment is prepared by dissolving 6 g of butylated hydroxy toluene as an antioxidant in 4 L of Aldrich reagent grade 1,2,4 trichlorobenzene (TCB). The TCB mixture is then filtered through a 0.7 μm glass pre-filter and subsequently through a 0.1 ptm Teflon filter. The TCB is then degassed with an online degasser before entering the SEC. Polymer solutions are prepared by placing the dry polymer in a glass container, adding the desired amount of TCB, then heating the mixture at 160° C. with continuous agitation for about 2 hr. All quantities are measured gravimetrically. The TCB densities used to express the polymer concentration in mass/volume units are 1.463 g/mL at room temperature and 1.324 g/mL at 135° C. The injection concentration ranges from 1.0 to 2.0 mg/mL, with lower concentrations being used for higher molecular weight samples. Prior to running each sample the DRI detector and the injector are purged. Flow rate in the apparatus is then increased to 0.5 mL/min, and the DRI was allowed to stabilize for 8-9 hr before injecting the first sample. The LS laser is turned on 1 to 1.5 hr before running samples. The concentration, c, at each point in the chromatogram is calculated from the baseline-subtracted DRI signal, I_DRI, using the following equation:

c=K_DRI^I_DRI/(dn/dc)

where K_DRI is a constant determined by calibrating the DRI, and dn/dc is the same as described below for the LS analysis. Units on parameters throughout this description of the SEC method are such that concentration is expressed in g/cm³, molecular weight is expressed in kg/mol, and intrinsic viscosity is expressed in dL/g.

The light scattering detector used is a Wyatt Technology High Temperature mini-DAWN. The polymer molecular weight, M, at each point in the chromatogram is determined by analyzing the LS output using the Zimm model for static light scattering (M. B. Huglin, LIGHT SCATTERING FROM POLYMER SOLUTIONS, Academic Press, 1971):

[K_oc/ΔR(θ,c)]=[1/MP(θ)]+2A₂c

where ΔR(θ) is the measured excess Rayleigh scattering intensity at scattering angle θ, c is the polymer concentration determined from the DRI analysis, A₂ is the second virial coefficient, P(θ) is the form factor for a monodisperse random coil (described in the above reference), and K_o is the optical constant for the system:

$K_o=\frac{4{\pi }^2{n^2\left(\mathrm{dn}/dc\right)}^2}{{\lambda }^4N_A}$

in which N_A is the Avogadro's number, and dn/dc is the refractive index increment for the system. The refractive index, n=1.500 for TCB at 135° C. and λ=690 nm. In addition. A₂=0.0015 and dn/dc=0.104 for ethylene polymers, whereas A₂=0.0006 and dn/dc=0.104 for propylene polymers.

The molecular weight averages are usually defined by considering the discontinuous nature of the distribution in which the macromolecules exist in discrete fractions i containing N_i molecules of molecular weight M_i. The weight-average molecular weight, M_w, is defined as the sum of the products of the molecular weight M_i of each fraction multiplied by its weight fraction w_i:

M_w≡Σw_iM_i=(ΣN_iM_i²/ΣN_iM_i)

since the weight fraction w_i is defined as the weight of molecules of molecular weight M_i divided by the total weight of all the molecules present:

w_i=N_iM_i/ΣN_iM_i

The number-average molecular weight, M_n, is defined as the sum of the products of the molecular weight M_i of each fraction multiplied by its mole fraction x_i:

M_n≡Σx_iM_i=ΣN_iM_i/ΣN_i

since the mole fraction x_i is defined as N_i divided by the total number of molecules x_i=N_i/ΣN_i.

In the SEC, a high temperature Viscotek Corporation viscometer is used, which has four capillaries arranged in a Wheatstone bridge configuration with two pressure transducers. One transducer measures the total pressure drop across the detector, and the other, positioned between the two sides of the bridge, measures a differential pressure. The specific viscosity, η_s, for the solution flowing through the viscometer is calculated from their outputs. The intrinsic viscosity, [η], at each point in the chromatogram is calculated from the following equation:

η_s=c[η]+0.3(c[η])²

where c was determined from the DRI output.

The branching index (g′, also referred to as g′(vis)) is calculated using the output of the SEC-DRI-LS-VIS method as follows. The average intrinsic viscosity. [η]_avg, of the sample is calculated by:

${\left[\eta \right]}_{\mathrm{avg}}=\frac{\sum {c_i\left[\eta \right]}_i}{\sum c_i}$

where the summations are over the chromatographic slices, i, between the integration limits.

The branching index g′ is defined as:

$g^{\prime }=\frac{{\left[\eta \right]}_{\mathrm{avg}}}{kM_v^{\alpha }}$

where k=0.000579 and α=0.695 for ethylene polymers; k=0.0002288 and α=0.705 for propylene polymers; and k=0.00018 and α=0.7 for butene polymers.
M_v is the viscosity-average molecular weight based on molecular weights determined by the LS analysis:

M_v≡(Σc_iM_i^α/Σc_i)^1/α

The polymer may have a viscosity (also referred to a Brookfield viscosity or melt viscosity), measured at 190° C. and determined according to ASTM D-3236 from about 100 cP to about 500,000 cP, or from about 100 to about 100,000 cP, or from about 100 to about 50,000 cP, or from about 100 to about 25,000 cP, or from about 100 to about 15,000 cP, or from about 100 to about 10,000 cP, or from about 100 to about 5,000 cP, or from about 500 to about 15,000 cP, or from about 500 to about 10,000 cP, or from about 500 to about 5,000 cP, or from about 1,000 to about 10,000 cP, wherein 1 cP=1 mPa·sec.

The polymers that may be used as polymer blends disclosed herein generally include any of the polymers according to the process disclosed in WO Publication No. 2013/134038. The triad tacticity and tacticity index of a polymer may be controlled by the catalyst, which influences the stereoregularity of propylene placement, the polymerization temperature, according to which stereoregularity can be reduced by increasing the temperature, and by the type and amount of a comonomer, which tends to reduce the length of crystalline propylene derived sequences. Such polymers made in accordance with WO Publication No. 2013/134038, when subjected to Temperature Rising Elution Fractionation, exhibit: a first fraction that is soluble at −15° C. in xylene, the first fraction having an isotactic (mm) triad tacticity of about 70 mol % to about 90 mol %; and a second fraction that is insoluble at −15° C. in xylene, the second fraction having an isotactic (mm) triad tacticity of about 85 mol % to about 98 mol %. The contents of WO Publication No. 2013/134038 and its parent application U.S. Patent Application Ser. No. 61/609,020 filed Mar. 9, 2012, are both incorporated herein in their entirety.

In any embodiment, one or more of the polymers described herein may be blended with another polymer, such as another polymer described herein, to produce a physical blend of polymers.

Methods for Preparing a Polymer Blend

The polymer blend of the invention comprising the two propylene-based polymers can be made in-reactor (e.g., in series or parallel), or outside the reactor (e.g., physical blend).

In one embodiment, the polymer blend is made in-reactor, for example, in parallel reactors. A solution polymerization process for preparing an exemplary polymer blend is generally performed by a system that includes a first reactor, a second reactor in parallel with the first reactor, a liquid-phase separator, a devolatilizing vessel, and a pelletizer. The first reactor and second reactor may be, for example, continuous stirred-tank reactors.

The first reactor may receive a first monomer feed, a second monomer feed, and a catalyst feed. The first reactor may also receive feeds of a solvent and an activator. The solvent and/or the activator feed may be combined with any of the first monomer feed, the second monomer feed, or catalyst feed or the solvent and activator may be supplied to the reactor in separate feed streams. A first polymer is produced in the first reactor and is evacuated from the first reactor via a first product stream. The first product stream comprises the first polymer, solvent, and any unreacted monomer.

The first monomer in the first monomer feed may be propylene and the second monomer in the second monomer feed may be ethylene or a C₄ to C₁₀ olefin. The second monomer may be ethylene, butene, hexene, and octene. Generally, the choice of monomers and relative amounts of chosen monomers employed in the process depends on the desired properties of the first polymer and final polymer blend. To enhance adhesive properties, ethylene and hexene are particularly preferred comonomers for copolymerization with propylene. The relative amounts of propylene and comonomer supplied to the first reactor may be designed to produce a polymer that is predominantly propylene, i.e., a polymer that is more than 50 mol % propylene. In another embodiment, the first reactor may produce a homopolymer of propylene.

The second reactor may receive a third monomer feed of a third monomer, a fourth monomer feed of a fourth monomer, and a catalyst feed of a second catalyst. The second reactor may also receive feeds of a solvent and activator. The solvent and/or the activator feed may be combined with any of the third monomer feed, the fourth monomer feed, or second catalyst feed, or the solvent and activator may be supplied to the reactor in separate feed streams. A second polymer is produced in the second reactor and is evacuated from the second reactor via a second product stream. The second product stream comprises the second polymer, solvent, and any unreacted monomer.

The third monomer may be propylene and the fourth monomer may be ethylene or a C₄ to C₁₀ olefin. The fourth monomer may be ethylene, butene, hexene, and octene. In any embodiment, the relative amounts of propylene and comonomer supplied to the second reactor may be designed to produce a polymer that is predominantly propylene, i.e., a polymer that is more than 50 mol % propylene. In another embodiment, the second reactor may produce a homopolymer of propylene.

Preferably, the second polymer is different than the first polymer. The difference may be measured, for example, by the comonomer content, heat of fusion, crystallinity, branching index, weight average molecular weight, and/or polydispersity of the two polymers. For example, the second polymer may comprise a different comonomer than the first polymer or one polymer may be a homopolymer of propylene and the other polymer may comprise a copolymer of propylene and ethylene or a C₄ to C₁₀ olefin. For example, in some embodiments, the first polymer may comprise a propylene-ethylene copolymer and the 25 second polymer may comprise a propylene-hexene copolymer. In some embodiments, the second polymer may have a different weight average molecular weight (Mw) than the first polymer and/or a different melt viscosity than the first polymer. Furthermore, in any embodiment, the second polymer may have a different crystallinity and/or heat of fusion than the first polymer. Specific examples of the types of polymers that may be combined to produce advantageous blends are described in greater detail herein.

It should be appreciated that any number of additional reactors may be employed to produce other polymers that may be integrated with (e.g., grafted) or blended with the first and second polymers. In any embodiment, a third reactor may produce a third polymer. The third reactor may be in parallel with the first reactor and second reactor, or the third reactor may be in series with one of the first reactor and second reactor.

Further description of exemplary methods for polymerizing the polymers described herein may be found in U.S. Pat. No. 6,881,800, which is incorporated by reference herein.

The first product stream and second product stream may be combined to produce a blend stream. For example, the first product stream and second product stream may supply the first and second polymer to a mixing vessel, such as a mixing tank with an agitator.

The blend stream may be fed to a liquid-phase separation vessel to produce a polymer rich phase and a polymer lean phase. The polymer lean phase may comprise the solvent and be substantially free of polymer. At least a portion of the polymer lean phase may be evacuated from the liquid-phase separation vessel via a solvent recirculation stream. The solvent recirculation stream may further include unreacted monomer. At least a portion of the polymer rich phase may be evacuated from the liquid-phase separation vessel via a polymer rich stream.

WO Publication No. 2013/134038 generally describes a method of preparing polyolefin adhesive components and compositions.

Thermoplastic Polyolefin

Any one of the layers described herein in a carpet or textile may comprise a thermoplastic polyolefin. Depending on the type and amount of the thermoplastic polyolefin, the final structure comprising the thermoplastic olefin may have thermoplastic, elastomeric, or thermoplastic elastomeric properties. Thermoplastic polyolefins suitable for use may include thermoplastic, crystalline polyolefin homopolymers, and copolymers. They are desirably prepared from monoolefin monomers having 2 to 7 carbon atoms, such as ethylene, propylene, 1-butene, isobutylene, 1-pentene, 1-hexene, 1-octene, 3-methyl-1-pentene, 4-methyl-1-pentene, 5-methyl-1-hexene, mixtures thereof and copolymers thereof with (meth)acrylates and/or vinyl acetates. Preferred, however, are monomers having 3 to 6 carbon atoms, with propylene being most preferred.

In some embodiments the thermoplastic polyolefin may be a functionalized olefin copolymers, such as functionalized propylene copolymer and functionalized ethylene copolymer, including a maleic anhydride functionalized olefin copolymer. Examples include those commercially available under the trade name EXXELOR™ (ExxonMobil Chemical Company, Texas, USA).

As used herein, the term “polypropylene” includes homopolymers of propylene as well as copolymers comprising propylene. Copolymers comprising propylene refer to reactor copolymers of polypropylene (reacted blends) and random copolymers containing more than 94% by weight of propylene, the remainder being selected from the comonomers (other than propylene) mentioned above, preferably ethylene. Typically, the random copolymers of polypropylene with ethylene contain about 1 to about 6 wt %, preferably less than about 6 wt % of ethylene and/or about 1 to about 30 wt % of an alpha-olefin comonomer of 4 to 16 carbon atoms, and mixtures thereof. The polypropylene can be highly crystalline isotactic or syndiotactic polypropylene.

The thermoplastic polyolefins mentioned above can be made by conventional Ziegler-Natta catalyst systems or by single-site catalyst systems, including polyolefins such as polyethylene copolymers obtained by metallocene catalysis with butene, hexene or octene as the comonomer. The amount of comonomer present in a polyethylene copolymer determines the density of the copolymer. Metallocene polymers or plastomers refer to polymers or plastomers prepared using a class of well-known highly active olefin catalysts known as metallocenes. These catalysts, particularly those based on group IV B transition metals such as zirconium, titanium and hafnium, show high activity in ethylene polymerization. The metallocene catalysts are also flexible in that, by manipulation of catalyst composition and reaction conditions, they can provide polyolefins with controllable molecular weights, as low as about 200 up to about 1 million or higher, and molecular weight distribution, from extremely narrow to broad. Metallocene catalysts are useful in making controlled ultra-uniform and super random specialty copolymers. For example, if a lower density ethylene copolymer is made with a metallocene catalyst, such as very low density polyethylene (VLDPE), an ultra-uniform and super random copolymerization will occur, as contrasted with the polymer produced by copolymerization using a conventional Ziegler catalyst.

Additives

Any one of the layers described herein in a carpet or textile can comprise a filler and/or additive. The materials described herein that are useful as fillers can be utilized alone or admixed to obtain desired properties. In any of the embodiments, the filler may be present at up to about 80 wt %, preferably up to about 70 wt %, more preferably from about 60 wt % to about 65 wt %, based on the total weight of the layer.

Desirable fillers can be organic fillers and/or inorganic fillers. Useful fillers include such materials as carbon black, fly ash, graphite, cellulose, starch, flour, wood flour, and polymeric fibers like polyester-based, polyamide-based materials, etc. Preferred examples of fillers are calcium carbonate, aluminum trihydrate, talc, glass fibers, marble dust, cement dust, clay, feldspar, silica or glass, fumed silica, alumina, magnesium oxide, antimony oxide, zinc oxide, barium sulfate, calcium sulfate, aluminum silicate, calcium silicate, titanium dioxide, titanates clay, nanoclay, organo-modified clay or nanoclay, glass microspheres and chalk. In some embodiments, the one or more layers may comprise a filler for improving the flame retardant properties of the carpet or textile, such as aluminum trihydrate or calcium carbonate.

A preferred additive is an inorganic filler. Examples of such fillers include, but are not limited to, calcium carbonate, aluminum trihydrate, talc, and barite. Inorganic mineral fillers can improve yarn encapsulation and locking which in turn improves the performance of the tuft bind strength and tuft lock strength. Preferably, filler is added at a level of up to about 80 wt %, preferably up to about 70 wt %, more preferably from about 60 wt % to about 65 wt %, based on the total weight of the extruded layer.

Other additives that may also be included include antioxidants such as sterically hindered phenols, sterically hindered amines and phospites may be used. Other possible additives include antiblock additives, pigments and colorants, anti-static agents, tackifiers (such as aromatic modified aliphatic hydrocarbon resins, e.g. those commercially available under the trade name ESCOREZ™ (ExxonMobil Chemical Company, Texas, USA)), compatibilizers (functionalized ethylene copolymers, preferably maleic anhydride functionalized elastomeric ethylene copolymers, e.g., those commercially available under the trade name EXXELOR™ (ExxonMobil Chemical Company, Texas, USA)), processing aids (such as stearic acid), antimicrobial agents (such as quaternary ammonium salts), chill roll release additives (such as fatty acid amides) and other aids (such as metallocene-based homopolymers, e.g., those commercially available under the trade name ACHIEVE™ (ExxonMobil Chemical Company, Texas, USA)).

Adhesion Layer

In some embodiments, the invention encompasses a carpet comprising a plurality of fibers and an adhesion layer for locking the plurality of fibers, as shown in FIG. 1. The adhesion layer comprises a polymer blend as described above, which comprises: (i) a first propylene-based polymer, wherein the first propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C₄ to C₁₀ alpha-olefin; (ii) a second propylene-based polymer, wherein the second propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C₄ to C₁₀ alpha-olefin, wherein the second propylene-based polymer is different than the first propylene-based polymer. The polymer blend has a melt viscosity, measured at 190° C. according to ASTM D-3236, of about 500 to about 25,000 cP.

In some embodiments where a carpet comprises a primary backing layer and second layer, as shown in FIG. 2, the adhesion layer can replace, or be in addition to, either or both of the primary backing layer and second layer.

The adhesion layer may directly or indirectly lock in the plurality of fibers. In some embodiments, the adhesion layer substantially locks in the plurality of fibers. In some embodiments, the carpet further comprises another (e.g., nonwoven) layer between the adhesion layer and the plurality of fibers. In some embodiments, the adhesion layer is substantially free of latex.

The adhesion layer may be continuous or discontinuous. For example, an adhesion layer can be discontinuous and lock in the plurality of fibers via a pattern or discrete zones. In some embodiments, the plurality of fibers are oriented in the same plane as the adhesion layer. This is in contrast to typical carpet structures where the fibers are in a different plane than (e.g., perpendicular or at an angle to) the adhesion layer. Whether the plurality of fibers are oriented at the same or different plane as the adhesion layer, the layer can be continuous or discontinuous (e.g., patterned or zoned).

The adhesion layer contains a polymer blend, and may further comprise a filler. In some embodiments, the adhesion layer further comprises a functionalized polymer.

Textile Layer

In some embodiments, the invention encompasses a textile or textile layer comprising a plurality of fibers and an adhesion layer for locking the plurality of fibers. The textile layer comprises, but can also be the adhesion layer itself, i.e., the textile layer and the adhesion layer can be a single layer. The adhesion layer comprises the polymer bend described herein.

The textile layer can contain fibers that are woven or nonwoven, natural or synthetic. Preferably, fibers in the textile layer are oriented in the same plane as the layer itself (e.g., a woven or nonwoven fabric). This distinguishes from a typical carpet structure where the fibers are in a different plane than (e.g., perpendicular or at an angle to) the layer.

The textile layer can be for use in upholstery (e.g., sofa, chair covers), or in other furniture such as mattresses. In such instances, fibers in the textile layer can be locked in or reinforced by the adhesion layer, whether as a continuous layer or discontinuous layer (e.g., patterned, zoned). FIGS. 3 (a) and (b) shows the exemplary discontinuous adhesion layers.

The layers described herein can be used in other applications, for example, in artificial grass or turf surfaces (e.g., AstroTurf™ grass). In such instances, the surface can comprise a plurality of synthetic grass and an adhesion layer described herein for locking in the plurality of grass, where in the adhesion layer comprises the polymer blend as described herein.

Carpet

In one embodiment, the invention encompasses a carpet comprising a plurality of fibers and an adhesion layer for locking the plurality of fibers. The adhesion layer comprises the polymer bend described herein. As shown in FIG. 1, the carpet may optionally comprise a thermoplastic laminate layer, a reinforcement layer, a thermoplastic cap layer, or other layer.

In some embodiments, as shown in FIG. 2, the carpet comprises a primary backing layer having a face side and a back side, and a plurality of fibers attached to the primary backing layer and extending from both the face side and the back side of the primary backing layer. As shown in FIG. 2, a second layer can be attached to the back side of the primary backing layer, and preferably locks in the plurality of fibers extending from the back side of the primary backing layer, and a thermoplastic laminate layer, a reinforcement layer, a thermoplastic cap layer can be optionally comprised. In such an embodiment, either the primary backing layer or the second layer can comprise (or itself be) an adhesion layer. Further, either or both of the primary backing layer and the second layer can comprise the polymer blend described herein. In some embodiments, the primary backing layer comprises a nonwoven layer, and the second layer comprises the polymer blend.

In some embodiments, compared to a conventional carpet comprising a latex precoat layer present in an amount of 18-28 oz/yd² (about 612-952 g/m² of latex), the adhesion layer may substantially eliminate the need for latex in the carpet. For example, in such embodiments the carpet may comprise no more than 150 g/m² of latex, or no more than 100 g/m² of latex, or no more than 50 g/m² of latex, or no more than 20 g/m² of latex, or 0 g/m² of latex.

Preferably, the carpet has an average relative mass loss, as measured according to EN 1963-A, of less than about 10%, preferably less than about 8%, and more preferably less than about 5%.

Preferably, the carpet has a tuft withdrawal force, as measured according to ISO 4949, of greater than about 1 N, preferably great than about 3 N, great than about 5 N, great than about 10 N, and more preferably greater than about 15 N.

In some embodiments, the primary backing layer may comprise a thermoplastic polyolefin. In other embodiments, the primary backing layer may be a nonwoven layer comprising bicomponent filaments. For example, the primary backing layer may comprise bicomponent continuous filaments having a polyethylene terephthalate core and a polyamide or polypropylene skin/sheath.

The face yarn may comprise various materials including, but not limited to, polypropylene, nylon, wool, cotton, acrylic, polyester, and polyethylene terephthalate (PET).

In some embodiments, the carpet can further comprise a third layer, for example, a thermoplastic laminate layer, attached to the second layer opposite to the primary backing layer. Preferably, the third layer comprises a thermoplastic polyolefin, such as a propylene-based elastomer.

In some embodiments, the carpet further comprises a reinforcement layer between the second layer and the third layer. Preferably, the reinforcement layer comprises at least one of thermoplastic fabrics and fiberglass.

Methods for Making Carnet

The invention also encompasses a method for making a carpet or a textile layer. The method comprises the steps of: (a) providing a plurality of fibers; (b) applying a melt comprising the polymer blend described herein to the plurality of fibers to form an adhesion layer for locking the plurality of fibers, and (c) forming a carpet or a textile layer.

Any conventional tufting or needle-punching apparatus and stitch patterns can be used to make the carpet. Tufted yarn loops may be left uncut to produce a loop pile; cut to make cut pile; or cut, partially cut and uncut to make a face texture known as tip sheared.

After the yarn is tufted or needle-punched into the primary backing layer, the greige good is typically rolled up with the back side of the primary backing layer facing outward and held until it is transferred to the backing line. In a preferred embodiment, the greige good is scoured or washed before it has a second layer extruded thereon. In particular, yarn that is tufted or needle-punched to make carpet often has varying quantities of processing materials, most commonly oily or waxy chemicals, known as spin-finish chemicals, remaining thereon from the yarn manufacturing processes. It has been found to be preferable to remove or displace all or substantially all of these processing materials prior to extruding the second layer comprising the polymer blend onto the back surface of the primary backing layer.

The adhesion layer can be applied via extrusion. In embodiments comprising a primary backing layer and second layer, the second layer can be applied by various methods, including extrusion coating and sheet lamination, with the preferred method involving the use of an extruded sheet of the polymer blend. In some embodiments, a third layer can be extrusion coated or sheet laminated onto the second layer. In particular, the molten polymer blend is extruded through a die so as to make a sheet which is as wide as the carpet. The molten, extruded sheet can applied to the back side of the primary carpet backing layer. Since the sheet is molten, the sheet will conform to the shape of the loops of yarn and further serve to fix the loops in the primary backing.

Extrusion coating configurations include a monolayer T-type die, single-lip die coextrusion coating, dual-lip die coextrusion coating, and multiple stage extrusion coating.

The line speed of the extrusion process will depend on factors such as the particular polymer being extruded, the exact equipment being used, and the weight of polymer being applied. The extrusion coating melt temperature principally depends on the particular polymer being extruded.

Auxiliary equipment such as a pre-heater can be used. In particular, a heater, such as a convection oven or infrared panels can be used to heat the back of the greige good before the second layer is extruded thereon. In doing so, it has been found that the encapsulation and locking of the yarn bundles can be enhanced.

As noted above, the carpet may also include a third layer. The third layer can be laminated in a later step by reheating and/or remelting at least the outermost portion of the extruded layer or by a coextrusion coating technique using at least two dedicated extruders.

The extrusion backed carpet construction and the methods described herein are particularly suited for making carpet tile. In one embodiment, yarn is tufted into a primary backing layer, so as to leave a carpet pile face on top of the primary backing layer and back stitches below the primary backing. Applied to the back of the primary backing layer and the back stitches is a second layer comprising a propylene-based elastomer. Preferably, the second layer further comprises a filler. The filler can be aluminum trihydrate with a loading of about 60 wt %, based on the total weight of the extruded layer.

When making carpet tile, it is preferable to embed a reinforcement layer between the second and third layers. An important property of carpet tile is dimensional stability, i.e., the ability of the tile to maintain its size and flatness over time. The inclusion of this layer of reinforcing material has been found to enhance the dimensional stability of carpet tile made according to this preferred embodiment. Suitable materials for the reinforcement layer include dimensionally and thermally stable fabrics such as fiberglass, as well as thermoplastic fabrics (e.g., polypropylene, nylon and polyester). Optionally, there is a middle layer present between the second layer and the reinforcement layer, preferably, also made from a thermoplastic polyolefin, which can be the same as or different from the propylene-based elastomer in the second layer.

Carpet tile is typically made by producing a length of backed carpet and then cutting the carpet into the appropriate sized squares. The most common sizes include 18 inches (45.7 cm) square, 24 inches (about 61.0 cm) square, or 50 cm square.

The carpets described herein may have improved properties, including tuft bind strength and tuft lock strength, and reliable construction, by substantially locking face yarn in place with use of a propylene-based elastomer, typically in a single layer replacing both the current precoat primarily comprising latex and the thermoplastic laminate layer. It can also be expected that the carpet, preferably without latex, may show such improved yarn adhesion when exposed to water, for there would be little latex decomposition leading to loss of tuft bind and tuft lock as it occurs in the conventional carpet.

Exemplary embodiments can include those described in the following paragraphs.

Embodiment A

A carpet comprising:

(a) a plurality of fibers; and

(b) an adhesion layer for locking the plurality of fibers, wherein the adhesion layer comprises a polymer blend containing:

• • (i) a first propylene-based polymer, wherein the first propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C₄ to C₁₀ alpha-olefin; and
  • (ii) a second propylene-based polymer, wherein the second propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C₄ to C₁₀ alpha-olefin; wherein the second propylene-based polymer is different than the first propylene-based polymer,

wherein the polymer blend has a melt viscosity, measured at 190° C. according to ASTM D-3236, of about 500 to about 25,000 cP.

Embodiment B

The carpet of Embodiment A, wherein the polymer blend has a melt viscosity, measured at 190° C. according to ASTM D-3236, of about 500 to about 25,000 cP and wherein, when subjected to Temperature Rising Elution Fractionation, the polymer blend exhibits: a first fraction that is soluble at −15° C. in xylene, the first fraction having an isotactic (mm) triad tacticity of about 70 mol % to about 90 mol %; and a second fraction that is insoluble at −15° C. in xylene, the second fraction having an isotactic (mm) triad tacticity of about 85 mol % to about 98 mol %.

Embodiment C

A carpet comprising:

(a) a plurality of fibers; and

(b) an adhesion layer for locking the plurality of fibers, wherein the adhesion layer comprises a polymer blend containing:

• • (i) a first propylene-based polymer, wherein the first propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C₄ to C₁₀ alpha-olefin; and
  • (ii) a second propylene-based polymer, wherein the second propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C₄ to C₁₀ alpha-olefin; wherein the second propylene-based polymer is different than the first propylene-based polymer,

wherein the polymer blend has a melt viscosity, measured at 190° C. according to ASTM D-3236, of about 500 to about 25,000 cP and wherein, when subjected to Temperature Rising Elution Fractionation, the polymer blend exhibits: a first fraction that is soluble at −15° C. in xylene, the first fraction having an isotactic (mm) triad tacticity of about 70 mol % to about 90 mol %; and a second fraction that is insoluble at −15° C. in xylene, the second fraction having an isotactic (mm) triad tacticity of about 85 mol % to about 98 mol %.

Embodiment D

The carpet of any one of Embodiments A to C, wherein the adhesion layer substantially locks in the plurality of fibers.

Embodiment E

The carpet of any one of Embodiments A to D, further comprising a nonwoven layer between the adhesion layer and the plurality of fibers.

Embodiment F

The carpet of any one of Embodiments A to E, wherein the adhesion layer is substantially free of latex.

Embodiment G

The carpet of any one of Embodiments A to F, wherein the adhesion layer further comprises a filler.

Embodiment H

The carpet of any one of Embodiments A to G, wherein the adhesion layer further comprises a functionalized polymer.

Embodiment I

A carpet comprising,

(a) a primary backing layer having a face side and a back side:

(b) a plurality of fibers attached to the primary backing layer and extending from both the face side and the back side of the primary backing layer, and

(c) a second layer attached to the back side of the primary backing layer,

wherein at least one of the primary backing layer and the second layer comprises a polymer blend comprising:

• • (i) a first propylene-based polymer, wherein the first propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C₄ to C₁₀ alpha-olefin; and
  • (ii) a second propylene-based polymer, wherein the second propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C₄ to C₁₀ alpha-olefin; wherein the second propylene-based polymer is different than the first propylene-based polymer.

Embodiment J

The carpet of Embodiment I, wherein the polymer blend has a melt viscosity, measured at 190° C. according to ASTM D-3236, of about 500 to about 25,000 cP and wherein, when subjected to Temperature Rising Elution Fractionation, the polymer blend exhibits: a first fraction that is soluble at −15° C. in xylene, the first fraction having an isotactic (mm) triad tacticity of about 70 mol % to about 90 mol %; and a second fraction that is insoluble at −15° C. in xylene, the second fraction having an isotactic (mm) triad tacticity of about 85 mol % to about 98 mol %.

Embodiment K

A carpet comprising.

(a) a primary backing layer having a face side and a back side:

(b) a plurality of fibers attached to the primary backing layer and extending from both the face side and the back side of the primary backing layer; and

(c) a second layer attached to the back side of the primary backing layer,

wherein at least one of the primary backing layer and the second layer comprises a polymer blend comprising:

• • (i) a first propylene-based polymer, wherein the first propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C₄ to C₁₀ alpha-olefin; and
  • (ii) a second propylene-based polymer, wherein the second propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C₄ to C₁₀ alpha-olefin; wherein the second propylene-based polymer is different than the first propylene-based polymer;

wherein the polymer blend has a melt viscosity, measured at 190° C. according to ASTM D-3236, of about 500 to about 25,000 cP and wherein, when subjected to Temperature Rising Elution Fractionation, the polymer blend exhibits: a first fraction that is soluble at −15° C. in xylene, the first fraction having an isotactic (mm) triad tacticity of about 70 mol % to about 90 mol %; and a second fraction that is insoluble at −15° C. in xylene, the second fraction having an isotactic (mm) triad tacticity of about 85 mol % to about 98 mol %.

Embodiment L

The carpet of any one of Embodiments I to K, wherein the primary backing layer comprises the polymer blend.

Embodiment M

The carpet of any one of Embodiment I or K, wherein the second layer comprises the polymer blend.

Embodiment N

The carpet of any one of Embodiments I to K, wherein the primary backing layer comprises a nonwoven layer, and the second layer comprises the polymer blend.

Embodiment O

The carpet of any one of Embodiments I to N, further comprising a third layer attached to the second layer opposite to the primary backing layer.

Embodiment P

The carpet of any one of Embodiments A, to O wherein the polymer blend has a melt viscosity, measured at 190° C. according to ASTM D-3236, of about 1,000 to about 10,000 cP.

Embodiment Q

The carpet of any one of Embodiments A to P, wherein the polymer blend comprises at least about 70 mol % of propylene-derived units.

Embodiment R

The carpet of any one of Embodiments A to Q, wherein the first propylene-based polymer and the second propylene-based polymer each comprises a copolymer of propylene and ethylene.

Embodiment S

The carpet of any one of Embodiments A to R, wherein the polymer blend has a heat of fusion of between about 10 to about 90 J/g.

Embodiment T

The carpet of any one of Embodiments A to S, wherein the first propylene-based polymer and the second propylene-based propylene polymer have a difference in heat of fusion of at least 10 J/g.

Embodiment U

The carpet of any one of Embodiments A to T, wherein the carpet comprises no more than 20 g/m² of latex.

Embodiment V

The carpet of any one of Embodiments A to U, wherein the carpet comprises 0 g/m² of latex.

Embodiment W

The carpet of any one of Embodiments A to V, wherein the carpet has an average relative mass loss, as measured according to EN 1963-A, of less than about 10%.

Embodiment X

The carpet of any one of Embodiments A to W, wherein the carpet has a tuft withdrawal force, as measured according to ISO 4949, of greater than about 3 N.

Embodiment Y

The carpet of any one of Embodiments A to X, wherein the polymer blend has a weight average molecular weight of from about 28,000 to about 48,000 g/mol.

Embodiment Z

The carpet of any one of Embodiments A to Y, wherein the polymer blend has a melt flow rate of from greater than about 1.500 g/10 min.

Embodiment AA

A textile layer comprising:

(a) a plurality of fibers; and

(b) an adhesion layer for locking the plurality of fibers, wherein the adhesion layer comprises a polymer blend containing:

• • (i) a first propylene-based polymer, wherein the first propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C₄ to C₁₀ alpha-olefin; and
  • (ii) a second propylene-based polymer, wherein the second propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C₄ to C₁₀ alpha-olefin; wherein the second propylene-based polymer is different than the first propylene-based polymer.

Embodiment AB

The textile layer of Embodiment AA, wherein the wherein the polymer blend has a melt viscosity, measured at 190° C. according to ASTM D-3236, of about 500 to about 25,000 cP and wherein, when subjected to Temperature Rising Elution Fractionation, the polymer blend exhibits: a first fraction that is soluble at −15° C. in xylene, the first fraction having an isotactic (mm) triad tacticity of about 70 mol % to about 90 mol %; and a second fraction that is insoluble at −15° C. in xylene, the second fraction having an isotactic (mm) triad tacticity of about 85 mol % to about 98 mol %.

Embodiment AC

The textile layer of Embodiment AA or AB, wherein the plurality of fibers are oriented in the same plane as the adhesion layer.

Embodiment AD

The textile layer of any one of Embodiments AA or AC, wherein the adhesion layer is discontinuous.

Embodiment AE

The textile layer of any one of Embodiments AA to AD, wherein the adhesion layer locks in the plurality of fibers in a pattern or in discrete zones.

Embodiment AF

The textile layer of any one of Embodiments AA to AE, wherein the polymer blend has a weight average molecular weight of from about 28,000 to about 48,000 g/mol.

Embodiment AG

The textile layer of any of Embodiments AA to AF, wherein the polymer blend has a melt flow rate of from greater than about 1,500 g/10 min.

Embodiment AH

A method for making a carpet or a textile layer, comprising the steps of:

(a) providing a plurality of fibers;

(b) applying a melt comprising a polymer blend to the plurality of fibers to form an adhesion layer for locking the plurality of fibers,

wherein the polymer blend comprises:

• • (i) a first propylene-based polymer, wherein the first propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C₄ to C₁₀ alpha-olefin; and
  • (ii) a second propylene-based polymer, wherein the second propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C₄ to C₁₀ alpha-olefin; wherein the second propylene-based polymer is different than the first propylene-based polymer; and

(c) forming a carpet or a textile layer.

Embodiment AI

The method of Embodiment AG, wherein the polymer blend has a melt viscosity, measured at 190° C. according to ASTM D-3236, of about 500 to about 25,000 cP and wherein, when subjected to Temperature Rising Elution Fractionation, the polymer blend exhibits: a first fraction that is soluble at −15° C. in xylene, the first fraction having an isotactic (mm) triad tacticity of about 70 mol % to about 90 mol %; and a second fraction that is insoluble at −15° C. in xylene, the second fraction having an isotactic (mm) triad tacticity of about 85 mol % to about 98 mol %.

Embodiment AJ

The method of Embodiment AH or AI, wherein the polymer blend is applied via extrusion.

Embodiment AK

The method of any one of Embodiments AH to AI, wherein the polymer blend has a weight average molecular weight of from about 28,000 to about 48,000 g/mol.

Embodiment AL

The method of any one of Embodiments AH to AI, wherein the polymer blend has a melt flow rate of from greater than about 1,500 g/10 min.

Examples

The foregoing discussion can be further described with reference to the following non-limiting Examples.

Polymer blends A to D were blends of two propylene-ethylene copolymers. In each polymer blend, the two propylene-ethylene copolymers were different in the ethylene contents and viscosities. The ethylene content and properties of the polymer blends A to D are shown in Table 2.

TABLE 2
Polymer Blend Properties
	Viscosity		Ethylene	Molecular	Melt Flow
Polymer	at 190° C.,	Shore	Content,	Weight,	Rate,
Blend	cP	Hardness C	%	g/mol	g/10 min
A	6000	14	12.1	36,640	4,000
B	6600	23	8.3	47,100	1,500
C	1150	51	5.8	29,210	>5,000
D	1200	52	6.7	28,730	>5,000

Examples 1 and 2, which are carpet samples containing Polymers A and B, respectively, were made by coating the polymer blends on carpet fibers via a conventional hot melt coating line, a melter/melt pump/flexible hose/coating die/carpet un-winding system. The carpet samples were evaluated using the following test: EN 1963-Method A(2007), Determination of mass loss of textile floor coverings using the Lisson Tretrad Machine. Exemplary conditions for making Examples 1 and 2 are set forth in Tables 3 and 4. As seen in Table 4, the average relative mass loss of Examples 1 and 2 are considered to be a “pass”.

TABLE 3
Coating Conditions
Smelter	Hose temp.	Die temp.	Line Speed	Set Polymer
temp. (C.°)	(C.°)	(C.°)	(m/min)	Yield (g/m2)
140-170	140-170	140-170	1.2	160-180

TABLE 4
Determination of Mass Loss via Lisson Tretrad Machine.
					Surface	Average
			Coating		pile	Relative
	Polymer		weight	Application	mass	mass loss
Example	Blend	Carpet Fiber	(avg. (g))	temp (° C.)	(g/m2)	(%)
1	A	Beige	432	140	264	8.2
		Polypropylene (PP)
2	B	Black	Approx. 240	170	532	9.8
		Polyamide (PA)

Examples 1-8, which are carpet samples containing Polymers A-D as indicated below, were made by the same method as in Examples 1 and 2 and evaluated using the following test: (2) ISO 4919 (2012), Determination of the tuft withdrawal force of textile floor covering. The results are shown in Table 5.

TABLE 5
ISO 4919 (2012). Determination of Tuft Withdrawal Force
			Coating		Average
	Polymer	Carpet	weight	Application	securing
Example	Blend	Fiber	(avg. (g))	temp (° C.)	force (N)
1	A	Beige PP	432	140	16.6
2	B	Black PA	Approx. 300	170	4.51
3	A	Black PA	Approx. 359	140	4.41
4	B	Beige PP	235	140	11.7
5	B	Beige PP	305	170	15.1
6	C	Beige PP	281	155	3.25
7	D	Beige PP	485	170	12.1
8	D	Black PA	253	170	3.6

Different carpet producers may have varying standards requiring certain levels of fiber adhesion depending on the carpet type, its intended use, and quality. Generally speaking, typical preferred levels for certain producers can be an average securing force of from IN up to 10 N.

In terms of material processability, Polymers A-D generally processed fine. However, at a processing temperature of 140° C. Polymer C did not result in sufficiently high flow. In terms of thermal stability, 24-hour ventilated oven aging with color measurement showed sufficient thermal stability for use in a conventional smelter.

Examples 1-8 did not contain modified or functionalized polymers (sometimes added to improve adhesion to non-polyolefin fibers), nor do they contain other fillers (typically added to reduce cost). Further, these samples did not contain latex, which is conventionally used as a backing system. It should also be noted that the carpet samples varied in structure, weight, number of loops, and loop length. The results show that despite the variation in structure, the carpet samples containing Polymers A-D performed well.

All documents described herein are incorporated by reference herein, including any priority documents and/or testing procedures. When numerical lower limits and numerical upper limits are listed herein, ranges from any lower limit to any upper limit are contemplated. As is apparent from the foregoing general description and the specific embodiments, while forms of the invention have been illustrated and described, various modifications can be made without departing from the spirit and scope of the invention. Accordingly, it is not intended that the invention be limited thereby.

Claims

1. A carpet comprising:

(a) a plurality of fibers; and

(b) an adhesion layer for locking the plurality of fibers, wherein the adhesion layer comprises a polymer blend containing: (i) a first propylene-based polymer, wherein the first propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C4 to C10 alpha-olefin; and (ii) a second propylene-based polymer, wherein the second propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C4 to C10 alpha-olefin; wherein the second propylene-based polymer is different than the first propylene-based polymer;

wherein the polymer blend has a melt viscosity, measured at 190° C. according to ASTM D-3236, of about 500 to about 25,000 cP.

2. The carpet of claim 1, wherein the polymer blend has a melt viscosity, measured at 190° C. according to ASTM D-3236, of about 1,000 to about 10,000 cP.

3. The carpet of claim 1, wherein the adhesion layer substantially locks in the plurality of fibers.

4. The carpet of claim 1, further comprising a nonwoven layer between the adhesion layer and the plurality of fibers.

5. The carpet of claim 1, wherein the polymer blend comprises at least about 70 mol % of propylene-derived units.

6. The carpet of claim 1, wherein the first propylene-based polymer and the second propylene-based polymer each comprises a copolymer of propylene and ethylene.

7. The carpet of claim 1, wherein the polymer blend has a heat of fusion of between about 10 to about 90 J/g.

8. The carpet of claim 1, wherein the first propylene-based polymer and the second propylene-based propylene polymer have a difference in heat of fusion of at least 10 J/g.

9. The carpet of claim 1, wherein the adhesion layer is substantially free of latex.

10. The carpet of claim 1, wherein the carpet comprises no more than 20 g/m2 of latex.

11. The carpet of claim 1, wherein the carpet comprises 0 g/m2 of latex.

12. The carpet of claim 1, wherein the adhesion layer further comprises a functionalized polymer.

13. The carpet of claim 1, wherein the carpet has an average relative mass loss, as measured according to EN 1963-A, of less than about 10%.

14. The carpet of claim 1, wherein the carpet has a tuft withdrawal force, as measured according to ISO 4949, of greater than about 3 N.

15. A carpet comprising:

(a) a primary backing layer having a face side and a back side;

(b) a plurality of fibers attached to the primary backing layer and extending from both the face side and the back side of the primary backing layer; and

(c) a second layer attached to the back side of the primary backing layer,

wherein at least one of the primary backing layer and the second layer comprises a polymer blend comprising: (i) a first propylene-based polymer, wherein the first propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C4 to C10 alpha-olefin; and (ii) a second propylene-based polymer, wherein the second propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C4 to C10 alpha-olefin; wherein the second propylene-based polymer is different than the first propylene-based polymer;

wherein the polymer blend has a melt viscosity, measured at 190° C. according to ASTM D-3236, of about 500 to about 25,000 cP.

16. The carpet of claim 15, wherein the primary backing layer comprises the polymer blend.

17. The carpet of claim 15, wherein the second layer comprises the polymer blend.

18. The carpet of claim 15, wherein the primary backing layer comprises a nonwoven layer, and the second layer comprises the polymer blend.

19. The carpet of claim 15, further comprising a third layer attached to the second layer opposite to the primary backing layer.

20. A textile layer comprising:

(a) a plurality of fibers; and

(b) an adhesion layer for locking the plurality of fibers, wherein the adhesion layer comprises a polymer blend containing: (i) a first propylene-based polymer, wherein the first propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C4 to C10 alpha-olefin; and (ii) a second propylene-based polymer, wherein the second propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C4 to C10 alpha-olefin; wherein the second propylene-based polymer is different than the first propylene-based polymer;

wherein the polymer blend has a melt viscosity, measured at 190° C. according to ASTM D-3236, of about 500 to about 25,000 cP.

21. The textile layer of claim 20, wherein the plurality of fibers are oriented in the same plane as the adhesion layer.

22. The textile layer of claim 20, wherein the adhesion layer is discontinuous.

23. The textile layer of claim 20, wherein the adhesion layer locks in the plurality of fibers in a pattern or in discrete zones.

24. A method for making a carpet or a textile layer, comprising the steps of:

(a) providing a plurality of fibers;

(b) applying a melt comprising a polymer blend to the plurality of fibers to form an adhesion layer for locking the plurality of fibers,

wherein the polymer blend comprises: (i) a first propylene-based polymer, wherein the first propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C4 to C10 alpha-olefin; and (ii) a second propylene-based polymer, wherein the second propylene-based polymer is a homopolymer of propylene or a copolymer of propylene and ethylene or a C4 to C10 alpha-olefin; wherein the second propylene-based polymer is different than the first propylene-based polymer,

wherein the polymer blend has a melt viscosity, measured at 190° C. according to ASTM D-3236, of about 500 to about 25,000 cP; and

(c) forming a carpet or a textile layer.

25. The method of claim 24, wherein the polymer blend is applied via extrusion.