RU2188265C2 - Carpet and method of its manufacture utilizing homogeneously branched polyethylene - Google Patents

Abstract

FIELD: textile industry. SUBSTANCE: invention relates to carpets suitable for fabricating large machine-sewn articles. Carpet contains primary warp with face and back sides, multitude of fibers attached to warp and sticking out from face side and remaining free on back surface, adhesive material, and optionally a secondary warp. At least one of materials of the primary and secondary warps and adhesive material is constituted by at least one HOMOGENEOUSLY branched polyethylene having short-chain branching distribution index higher than or equal to 70%. Back side of primary warp is coated by adhesive material and optionally by secondary warp using extrusion technique. EFFECT: improved strength of nap interweaving, wear resistance, barrier properties, and elasticity. 14 cl, 9 dwg, 19 tbl, 208 ex

Description

 This invention relates to carpets and methods for producing carpets, in which the carpets contain at least one flexible polyethylene base material. In particular, the invention relates to a carpet and a method for producing a carpet by extrusion coating technology, in which the carpet contains a base material comprising at least one homogeneously branched ethylene polymer.

 The present invention relates to any carpet composed using a primary backing material, and includes a piercing carpet and a non-piercing carpet, such as a needle-punched carpet. Although the individual options are applicable to the piercing carpet and to the non-piercing carpet, piercing carpet is preferred.

 As shown in FIG. 1, piercing carpets are composite structures that include yarn (which is also known as a fiber bundle), a primary backing material having a front surface and a back surface, an adhesive backing material and, optionally, a secondary backing material. To form the front surface of the piercing carpet, the yarn is sewn through the primary backing material, so that the long length of each stitch passes through the front surface of the primary backing material. Typically, the primary backing material is made from a woven or non-woven material, such as a thermoplastic polymer, most often polypropylene.

 The front side of the piercing carpet can be made in three ways. Firstly, for a knitted carpet, the yarn loops formed during the flashing process are solid inside out. Secondly, for a split pile carpet, the yarn loops are cut either during the flashing process, or after yielding a bundle of single yarn ends instead of loops. Thirdly, some carpet models include both a loop and a split pile. One variation of this hybrid relates to a carpet with trimmed ends, where loops with different lengths are stitched, followed by cutting the carpet in height so as to obtain uncut, partially cut and completely cut loops. Alternatively, the pile carpet machine can be designed to cut only some loops, leaving a pattern of cut and uncut loops as a result. When the loop is cut or in the case of a hybrid, the yarn on the back of the primary backing material contains dense unstretched loops.

 The combination of stitched yarn and primary backing material without applying an adhesive backing material or secondary backing material is called in the carpet industry a coarse stitched carpet or unfinished products. Unfinished products become trimmed with stitched carpet by applying an adhesive backing material and, optionally, a secondary backing material to the back of the primary backing material. A trimmed stitched carpet can be obtained in the form of a large-format carpet on rolls, usually 1.8 or 3.6 m wide.

 Alternatively, the carpet may be in the form of carpet tiles, typically 18 square inches in the United States and 50 cm in other countries.

 The adhesive backing material is applied to the back side of the primary backing material for bonding the yarn to the primary backing material. Typically, the adhesive backing material is applied with a tray applicator using a roll, a roll over a roll or layer, or a knife (also called a squeegee) over a roll or layer. Properly applied adhesive base materials practically do not pass through the primary base material.

 Most often, the adhesive backing material is applied as a single coating or layer. The degree or strength with which the yarn is bonded is called the strength of a pile bundle or pile weave. Carpets with sufficient pile weave strength have good wear resistance and as such have a long service life. In addition, the adhesive backing material should significantly impregnate the yarn (fiber bundle) located on the back of the primary backing material and should significantly combine the individual fibers in the yarn. Good impregnation of the yarn and the combination of fibers gives good wear resistance. In addition, in addition to good pile weave strength and wear resistance, the adhesive material should also give the carpet or provide good elasticity in order to facilitate ease of carpet installation.

 The secondary backing material is usually a lightweight canvas made of a woven or non-woven material, such as a thermoplastic polymer, most often polypropylene. The secondary backing material is optionally applied to the back of the carpet on an adhesive backing material, primarily to provide improved dimensional stability of the carpet structure, as well as providing a larger surface area for applying direct adhesive adhesives.

 Alternative backing materials may also be applied to the back of the adhesive backing material and / or to the back of the secondary backing material, if present. Alternative backing materials may include foam cushioning (e.g., foamed polyurethane) and pressure sensitive filling adhesives. Alternative backing materials can be applied, for example, as a fabric with an increased surface area to facilitate the use of direct bonding adhesives (for example, in the manufacture of industrial carpeting, car flooring and aircraft carpet, where the need for cushioning is often minimal). Alternative base materials may also be used to improve barrier protection against moisture, insecticides and food products; as well as to provide or improve flame retardation, thermal insulation and sound-absorbing properties of the carpet.

 Known adhesive backing materials include vulcanized latex, urethane or vinyl systems, with latex systems being the most common. Traditional latex systems are low viscosity water compositions that are applied at high carpet production rates and have good fiber adhesion to the base, pile strength and adequate elasticity. Typically, excess water is discharged and the latex is vulcanized as it passes through the oven. Styrene butadiene rubbers (BSK) are the most common polymers used for latex adhesive backing materials. Typically, the latex base system is heavily filled with an inorganic filler such as calcium carbonate or aluminum trihydrate and includes other ingredients such as antioxidants, antimicrobial additives, flame arresters, smoke suppressants, wetting agents and blowing agents.

 Traditional latex adhesive backing systems may have some disadvantages. One of the important disadvantages of typical latex adhesive backing systems is not providing a barrier to moisture. Another possible disadvantage, especially for a carpet having polypropylene yarn and polypropylene materials of a primary and secondary basis, is that a heterogeneous polymer of latex systems together with an inorganic filler can reduce the reusability of the carpet.

 From the point of view of these shortcomings, the carpet industry is considering appropriate replacements for traditional latex adhesive backing systems. One alternative is to use urethane adhesive backing systems. In addition to providing adequate adhesion to strengthen the carpet, urethane substrates usually have good elasticity and barrier properties and, when foaming, can eliminate the need for a separate underlying lining (i.e. they can form a direct adhesive single base system). However, urethane backing systems also have important disadvantages, including their relatively high cost and vulcanization requirements, which must be applied at low carpet production rates with respect to latex systems.

 Thermoplastic polyolefins, such as ethylene vinyl acetate (EVA) and low density polyethylene (LDPE) copolymers, are also available as adhesive backing materials due in particular to their low cost, good moisture resistance and lack of vulcanization requirements. Various methods are available for applying polyolefin base materials, including powder coating, melt and extruded film, or sheet lamination. However, the use of polyolefins instead of latex adhesive bases can also have disadvantages. For example, US Pat. No. 5,240,530, Table A, column 10, indicates that conventional polyolefin resins have inadequate adhesion for use in carpet construction. Additionally, with respect to latex and other vulcanizing systems, conventional polyolefins have relatively high application viscosities and relatively high thermal requirements. Those. conventional thermoplastic polyolefins are characterized by relatively high melt viscosities and high recrystallization or solidification temperatures relative to the typical characteristics of aqueous viscosities and temperature requirements for the vulcanization of latex and other vulcanized (thermoset) systems.

 Even conventional elastomeric polyolefins, for example, low crystallinity polyolefins, typically have relatively high viscosities and relatively high recrystallization temperatures. High recrystallization temperatures give relatively short melting times during processing and, in combination with high melt viscosities, can make it difficult to achieve adequate impregnation of the yarn, especially at traditional application rates of the adhesive backing.

 One way to overcome the viscous and recrystallization disadvantages of conventional polyolefins is to formulate the polyolefin resin as a hot-melt adhesive, which typically involves the formulation of low molecular weight polyolefins with waxes, tackifiers, various flow modifiers and / or other elastomeric materials. Ethylene vinyl acetate (EVA) copolymers, for example, are used in the formulations of hot-melt adhesive base compositions, and other polyolefin compositions are offered as hot-melt base compositions. For example, US Pat. No. 3,982,051 (Taft et al.) Teaches that a composition comprising an ethylene vinyl acetate copolymer, atactic polypropylene and vulcanized rubber is used as a hot-melt adhesive of a carpet base.

 Unfortunately, hot-melt adhesive systems are generally not considered a fully suitable replacement for traditional latex adhesive substrates. Typical hot melt systems based on EVA and other copolymers of ethylene and unsaturated comonomers may require complex formulations and even often give inadequate pile strengths. However, the most significant drawback of typical hot melt systems is their melt strengths, which are usually too low to allow direct extrusion coating. As such, polyolefin hot melt systems are typically applied to primary substrates with relatively slow, less efficient technologies, such as the use of heated squeegees or rotating melt transfer rolls.

 Although OTC low-density polyethylene (LDPE) can be applied by conventional extrusion coating technology, LDPE resins generally have poor elasticity, which can lead to excessive carpet stiffness. On the other hand, those conventional polyolefins that have improved elasticity, such as ultra low density polyethylene (VLDPE) and ethylene and propylene interpolymers, do not yet have sufficient elasticity, have extremely low melt strengths and / or tend to resonate during extrusion coating. To overcome the disadvantages of extrusion coating, conventional polyolefins with sufficient elasticity can be applied by lamination technology to ensure adequate adhesion of the yarn to the base; however, lamination technology is usually expensive and can lead to slow production speeds relative to direct extrusion coating technologies.

 Known examples of elastic polyolefin base materials are discussed in US Pat. Known methods for improving the permeability of hot-melt adhesive backing compositions through yarn include applying pressure when the untreated product is in contact with rotating melt transfer rolls, as described, for example, in US Pat. No. 3,551,231.

 Another known method for improving the efficiency of hot melt systems involves the use of primer systems. For example, US Pat. The hot-melt adhesive base systems discussed in these patents are derived from multicomponent formulations based on functional ethylene polymers, such as, for example, copolymers of ethylene and ethyl acrylate (EEA) and ethylene with vinyl acetate (EVA).

 Although various systems are known in the carpet backing technique, there remains a need for a thermoplastic polyolefin carpet backing system that provides adequate pile weave strength, good wear resistance and good elasticity, instead of vulcanized latex backing systems. There is also a need for a method of application that provides high carpet production rates while achieving the desired characteristics of good pile weave strength, wear resistance, barrier properties and elasticity. Finally, there is also the need to create a carpet structure having fibers and warp materials that are easily recyclable without the need for intensive processing and separation of the constituent materials of the carpet.

 In accordance with one aspect of the present invention, the carpet comprises a plurality of fibers, a primary backing material having a front and a back side, an adhesive backing material and an optional secondary backing material, the plurality of fibers being attached to the primary backing material and protruding from the front side of the primary backing material and remains free on the back of the primary backing material, adhesive backing material is located on the back of the primary backing material, and optional secondary material a base is adjacent to an adhesive base material, where at least one of the plurality of fibers, a primary base material, an adhesive base material or an optional secondary base material consists of at least one homogeneously branched ethylene polymer characterized as having a short chain distribution index branching (PRKRC), greater than or equal to 50%.

 Another aspect of the present invention is a method for producing a carpet, the carpet comprising a plurality of fibers, a primary backing material having a front and a back side, an adhesive backing material and an optional secondary backing material, the plurality of fibers being attached to the primary backing material and protruding from the front side of the primary backing material and remains free on the back of the primary backing material, the method comprising the step of extruding the coating of an adhesive backing material or neo the secondary backing material on the back of the primary backing material, where the extruded adhesive backing material or optional secondary backing material consists of at least one homogeneously branched ethylene polymer characterized as having a short chain branching distribution index (SCRC) of greater than or equal to 50 %

 Another aspect of the present invention is a method for producing a carpet, wherein the carpet has a compressed unstretched matrix of adhesive base material and contains yarn attached to the primary base material, the adhesive base material contains at least one ethylene polymer and is in direct contact with the primary base material and has a substantially permeable substantially combined yarn, the method comprising the step of introducing an effective amount of at least one detonating agent into the adhesive th base material and then activating the implosion agent during an extrusion coating step of applying so that molten or semi-molten polymer is forced into the free space of yarn exiting freely on the backside of the primary backing material.

 Another aspect of the present invention is a method for producing a carpet, wherein the carpet has a front surface and comprises yarn, primary backing material, adhesive backing material and optional secondary backing material, where the primary backing material has a back surface opposite to the front surface of the carpet, the yarn is attached to the primary backing material , the adhesive backing material is applied to the back surface of the primary backing material, and the optional secondary backing material is applied to the adhesive backing terium of the base, the method comprising the step of cleaning, washing or evaporating the back surface of the primary base material with steam, solvent and / or heat before applying the adhesive base material with the practical removal or replacement of processing aids.

 Figure 1 shows the stitched carpet 10.

 In FIG. 2 schematically shows an extrusion coating line 20 for producing carpet 70.

 Figure 3 presents microphotographs obtained by scanning electron microscopy at a magnification of 20 x (3A) and a magnification of 50 x (3B), illustrating the interface between the various carpet components from example 14.

 Figure 4 presents microphotographs obtained by scanning electron microscopy at a magnification of 20 x (4A) and a magnification of 50 x (4B), illustrating the interface between the various carpet components from example 22.

 In FIG. Figure 5 shows a graph in the X-Y axis system of the effect of impregnation of a fiber bundle with an adhesive base material on the wear resistance of polypropylene and polyamide carpets.

 In FIG. 6 is a cross-sectional view showing the construction of carpet tile in accordance with the present invention.

 In FIG. 7 is a schematic representation of an extrusion coating line for producing carpet tile according to the present invention.

 The terms “direct contact”, “significant encapsulation” and / or “significant association” are used here to mean mechanical adhesion or mechanical interactions (as opposed to chemical bonding) between dissimilar carpet components, whether or not one or more carpet components is capable of interacting with another carpet component. Regarding the mechanical adhesion or interactions of the present invention, there is a certain effective amount of intermiscible or intermeltable polymeric materials; however, there is no continuous or integral melting of various components, as determined from visual analysis of microphotographs (at 20 x magnification) of various carpet interfaces. In this sense, the melting of yarn (or bundles of fibers) or individual fibers from one another in a bundle of fibers is not considered integral melting in the fibers themselves, which are referred to herein as one carpet component.

 The term "direct contact" refers to the mechanical interaction between the back surface of the primary backing material and the adhesive backing material.

 The term “significant encapsulation” refers to an adhesive backing material substantially surrounding yarn (or bundles of fibers) at or in close proximity to the interface between the back surface of the primary backing material and the adhesive backing material.

 The term "significant association" refers to the overall integrity and dimensional stability of the carpet, which is achieved by significantly encapsulating the yarn (or fiber bundles) and directly contacting the back surface of the primary backing material with an adhesive backing material. A significantly combined carpet has good component cohesion and good resistance to delamination relative to various carpet components.

 The term "integral melting" (fusion) is used here in the same sense as is known in the art, and refers to the thermal bonding of carpet components using a temperature above the melting point of the adhesive base material. Integral melting occurs when the adhesive backing material contains the same polymer as either the fibers, or the primary backing material, or both. However, integral melting does not occur when the adhesive backing material contains a different polymer than the fibers and the primary backing material. The term "same polymer" means that the monomer units of the polymers are of the same chemical nature, although their molecular or morphological characteristics may be different. On the other hand, the term "different polymer" means that, regardless of any molecular or morphological differences, the chemistry of the monomer units of the polymers is the same. Thus, in accordance with various definitions of the present invention, the polypropylene primary backing material and the polyethylene adhesive backing material will not integrally melt, because the chemistry of these carpet components is different.

 The term "carpet component" is used here to denote separately carpet bundles of fibers, material of the primary base, adhesive material of the base and optional material of the secondary base.

 The term "extrusion coating" is used here in its usual sense to refer to extrusion technology in which the polymer composition is usually granulated in an extruder at a temperature above its melting point and then injected through a slot head to form a semi-molten or molten polymer web. A semi-molten or molten polymer web is continuously discharged onto a continuously fed unfinished product coated on the back of the unfinished product with a polymer composition. Figure 2 shows the extrusion method of the present invention, in which on the clamp the front surface of the unfinished product is oriented to the cooling roll, and the back surface of the adhesive base material is oriented to the pressure roll. Extrusion coating is different from lamination technology.

 The term "lamination technology" is used here in its usual sense to mean the application of adhesive backing materials to unfinished products by first forming the adhesive backing material in the form of a hardened or substantially hardened film or sheet and then at a separate processing stage to reheat or increase the temperature of the film or sheet before applying it to the back surface of the primary base material.

 The term "heat content" is used here to mean the mathematical product of the heat capacity and specific gravity of the filler. Fillers characterized as having a high heat content are used in certain embodiments of the present invention to increase the curing or melting time of the adhesive base materials. Handbook for Chemical Technicians, Howard J. Strauss and Milton Kaufmann, McGraw Hill Book Company, 1976, Sections 1-4 and 2-1, provide information on the specific heat and specific gravity of the selected mineral fillers. Fillers suitable for use in the present invention do not change their physical state (i.e., remain solid material) within the temperature ranges of the extrusion coating of the present invention. Preferred high heat fillers have a combination of high specific gravity and high heat capacity.

 The term “exploding agent” is used herein to mean the use of traditional blowing agents or other compounds that emit gas or cause gas evolution when activated by heat, usually at a certain specific activation temperature. In the present invention, detonating agents are used to blast or pump the adhesive backing material into the free space of the yarn (or fiber bundles).

 The term “processing aid” is used herein to mean substances, such as spinning finishing waxes, machine oils, sizing agents, and the like, which may interfere with adhesive or physical interactions at the interface of the adhesive base materials. Processing aids can be removed or replaced by cleaning or rinsing the present invention, resulting in improved mechanical bonding.

 The terms "polypropylene carpet" and "polypropylene unfinished products" are used herein to mean carpet or unfinished products essentially consisting of polypropylene fibers, regardless of whether the primary carpet backing material or unfinished product consists of polypropylene or the same other material.

 The terms "polyamide carpet" and "polyamide unfinished products" are used here to denote carpet and unfinished products essentially consisting of polyamide fibers, regardless of whether the primary carpet backing material or unfinished product consists of polyamide or the same other material.

 The term “linear”, as used to describe ethylene polymers, is used here to mean that the polymer backbone of the ethylene polymer does not have detectable and visible long chain branches, for example, the polymer is replaced on average with less than 0.01 long chain branches per 1000 carbons.

 The term "homogeneous ethylene polymer", as used here to describe ethylene polymers, is used here in the usual sense in accordance with the primary description of US patent 3645992 (Elston) to denote an ethylene polymer in which the comonomer is statistically distributed in a given polymer molecule, and in which all polymer molecules have virtually the same molar ratio of ethylene and comonomer. As defined herein, both substantially linear ethylene polymers and homogeneously branched linear polyethylene are homogeneous ethylene polymers.

 Homogenously branched ethylene polymers are homogeneous ethylene polymers that have short chain branching and that are characterized by a relatively high short chain branching distribution index (PRRC) or relatively high composition branching distribution index (PRRC). Those. the ethylene polymer has PRKR or PRRK more than or equal to 50%, preferably more than or equal to 70%, more preferably more than or equal to 90%, and essentially does not have a detectable fraction of high density polymer (crystalline).

PRKR or PRRK is defined as the mass percentage of polymer molecules having a comonomer content of 50% of the average total molar content of comonomer, and represents a comparison of the distribution of comonomer in the polymer with the distribution of comonomer expected for the Bernoulli distribution. RCCR or PRRK of polyolefins can be conveniently calculated using data obtained by methods known in the art, such as, for example, fractionation by elution with increasing temperature (hereinafter abbreviated as “HIFE”), as described, for example, in Wild et al., Journal of Polymer Science, Poly. Phys. Ed. , Vol. 20, p. 441 (1982), LD Cady, "The Role of Comonomer Type and Distribution in LLDPE Product Performance", SPE Regional Technical Conference, Quaker Square Hilton, Akron, Ohio, October 1-2, pp. 107-119 (1985) or US Pat. Nos. 4,798,081 and 5,008,204. However, the preferred HPHT method does not include the purge amount in the RCCR or RRC calculations. More preferably, the distribution of comonomer in the polymer and PRKR or PRKR determined using ¹³ C NMR analysis in accordance with the method described, for example, in US patent 5292845 and in the work of JC Randall, Rev. Macromol. Chem. Phys., C29, pp. 201-317.

 The terms “homogeneously branched linear ethylene polymer” and “homogeneously branched linear ethylene and alpha olefin polymer” mean that the olefin polymer has a homogeneous or narrow distribution of short chain branching (i.e., the polymer has a relatively high RCCR or PRRC), but does not have a long chain branching. Those. a linear ethylene polymer is a homogeneous ethylene polymer characterized by the absence of long chain branching. Such polymers can be prepared using polymerization methods (for example, as described in US Pat. No. 3,645,992 (Elston), which provide a uniform distribution of short chain branches (i.e., homogenously branched). In its polymerization method, Elston uses soluble vanadium catalyst systems polymers, however others, such as Mitsui Petrochemical Industries and Exxon Chemical Company, reportedly use so-called single-center catalyst systems to produce polymers having a homogeneous a structure similar to the polymer described by Elston US Pat. No. 4,937,299 (Ewen et al.) and US Pat. No. 5,218,071 (Tsutsui et al.) disclose the use of metallocene catalysts, such as hafnium based catalyst systems, to produce homogeneously branched linear ethylene polymers.

Homogenously branched ethylene polymers are typically characterized as having a molecular weight distribution of Mw / Mn of less than 3, preferably less than 2.8, more preferably less than 2.3. Commercial examples of corresponding homogeneously branched linear ethylene polymers include those sold by Mitsui Petrochemical Industries as Tafmer ^tm resins and Exxon Chemical Company as Exact ^tm resins and Exceed ^tm resins.

The terms “homogeneous linearly branched ethylene polymer” or “homogeneous branched linear ethylene and alpha-olefin polymer” do not refer to branched high pressure polyethylene, which, as is known to those skilled in the art, has numerous long chain branches. The term “homogeneous linear ethylene polymer” generally refers to both linear ethylene homopolymers and linear ethylene and alpha-olefin interpolymers. The linear interpolymer of ethylene and alpha-olefin has a short chain branching, and the alpha olefin is at least one alpha-C _3-20 olefin (e.g., propylene, 1-butene, 1-pentene, 4-methyl-1 pentene, 1-hexene, and 1-octene).

 When used in relation to an ethylene homopolymer (for example, high density polyethylene containing no comonomer and thus no short chain branching), the term “homogeneous ethylene polymer” or “homogeneous linear ethylene polymer” means that the polymer was prepared using a homogeneous catalytic system, such as, for example, the system described by Elston or Even, or the systems described in US patents 5026798 and 5055438 (Canich) or in US patent 5064802 (Stevens et al.).

 The term “substantially linear ethylene polymer” is used specifically here to refer to homogeneously branched ethylene polymers that have long chain branching. The term does not refer to heterogeneously or homogeneously branched ethylene polymers that have a linear polymer backbone. For substantially linear ethylene polymers, long chain branches have the same comonomer distribution as the polymer backbone, and long chain branches can be approximately the same length as the length of the polymer main chain to which they are attached. The polymer backbone of the substantially linear ethylene polymers is substituted with from about 0.01 long chain branches / 1000 carbons to about 3 long chain branches / 1000 carbons, more preferably from about 0.01 long chain branches / 1000 carbons to about 1 long chain branches / 1000 carbons, and especially from about 0.05 long chain branches / 1000 carbons to about 1 long chain branch / 1000 carbons.

Long chain branching is defined here as a chain length of at least 6 carbons, more than which the length cannot be different using ¹³ C NMR spectroscopy. The presence of long chain branching can be determined in ethylene homopolymers using ¹³ C NMR spectroscopy and quantified using the method described by Randall, Rev. Macromol. Chem. Phys., C29, V. 2 and 3, pp. 285-297.

Although modern ¹³ C NMR spectroscopy cannot determine the length of long chain branching in excess of 6 carbon atoms, there are other known methods for determining the presence of long chain branching in ethylene polymers, including ethylene and 1-octene interpolymers. Two such methods are gel permeation chromatography paired with a low-angle laser beam scattering detector (GPC-NURLL) and gel permeation chromatography paired with a differential viscometer detector (GPC-DV). The use of these methods for determining long chain branching and underlying theories are well represented in the literature. See, for example, Zimm, GH and Stockmayer, WH, J. Chem. Phys., 17, 1301 (1949) and Rudin, A., Modern Method of Polymer Characterization, John Wiley & Sons, New York (1991), pp. 103-112.

In A. Willem de Groot and P. Steve Chum (both from The Dow Chemical Company), at the October 4, 1994 conference of the Federation of Analytical Chemistry and Spectroscopy Society (FACSS) in St. Louis, Missouri, presents data showing that GPC-DV is a used method for quantifying the presence of long chain branches in substantially linear ethylene polymers. In particular, the authors found that the content of long chain branches in samples of essentially linear ethylene homopolymers, measured using the Zimm-Stokmeier equation, correlates well with the level of content of long chain branches measured using ¹³ C NMR.

 In addition, these authors found that the presence of octene does not change the hydrodynamic volume of polyethylene samples in solution, and, as such, it can be calculated to increase the molecular weight inherent for short-chain branching octenes based on the known molar percentage of octene in the sample. By establishing the contribution of the increase in molecular weight inherent to 1-octene short chain branches, these authors showed that the GPC-DV method can be used to quantify the level of content of long chain branches in essentially linear ethylene-octene copolymers.

These authors also showed that a graph of log (melt index I ₂ ) as a function of log (weight-average molecular weight by GPC), as determined by GPC-DV, shows that the type of long chain branching (but not the degree of long chain branching) of substantially linear ethylene polymers comparable with highly branched low density polyethylene (LDPE), high pressure and dramatically different from ethylene polymers obtained using Ziegler catalysts such as titanium complexes and conventional homogeneous catalysts, so x as hafnium and vanadium complexes.

For substantially linear ethylene polymers, long chain branching is longer than short chain branching, which is the result of introducing alpha olefin (s) into the polymer backbone. The empirical effect of the presence of long chain branching in the substantially linear ethylene polymers used in the invention is manifested in the form of improved rheological properties that are quantified and expressed here as gas extrusion plastometry (HEP), and / or melt flow ratio I ₁₀ / I ₂ increases .

The substantially linear ethylene polymers are homogeneously branched ethylene polymers and are discussed in U.S. Patent 5272236 and U.S. Patent 5,278,272 Homogeneously branched substantially linear ethylene polymers are available from the firm The Dow Chemical Company as the AFFINITY ^TM polyolefin plastomers and from the company DuPont Dow Elastomers JV as an polyolefin elastomers ENGAGE ^tm . Homogeneously branched substantially linear ethylene polymers can be prepared by solution, suspension or gas phase polymerization of ethylene and one or more optional alpha olefin comonomers in the presence of a cramped catalyst, such as the method described in European Patent 416815A. Preferably, a solution polymerization process is used to produce the substantially linear ethylene polymer used in the present invention.

The terms “heterogeneous” and “heterogeneously branched” mean that the ethylene polymer is characterized as a mixture of interpolymer molecules having different molar ratios of ethylene and comonomer. Heterogeneously branched ethylene polymers are characterized as having a short-chain branching distribution index (SCRC) of less than about 30%. Heterogeneously branched linear ethylene polymers are available from The Dow Chemical Company as DOWLEX ^tm linear low density polyethylene and ATTANE ^tm ultra low density polyethylene resins. Heterogeneously branched linear ethylene polymers can be prepared by solution, suspension or gas phase polymerization of ethylene and one or more optional alpha olefin comonomers in the presence of a Ziegler-Natta catalyst by methods such as in US Pat. No. 4,076,698 (Anderson et al.). Heterogeneously branched ethylene polymers are generally characterized as having molecular weight distributions M _w / M _n ranging from 3.5 to 4.1 and as such differ from substantially linear ethylene polymers and homogeneously branched linear ethylene polymers in terms of both compositional distribution short chain branching and molecular weight distribution.

 The substantially linear ethylene polymers used in the present invention do not belong to the same class as the homogeneously branched linear ethylene polymers nor the heterogeneously branched linear ethylene polymers, and are not essentially linear ethylene polymers in the same class as the traditional low branched polyethylene density (LDPE).

The substantially linear ethylene polymers used in this invention unexpectedly have excellent processability, although they have relatively narrow molecular weight distributions (MMPs). Even more unexpectedly, the melt flow ratio (I ₁₀ / I ₂ ) of the substantially linear ethylene polymers can vary virtually independently of the polydispersity index (i.e., the molecular weight distribution M _w / M _n ). This contrasts with traditional heterogeneously branched linear polyethylene resins that have such rheological properties that with an increase in the polydispersity index, the value of I ₁₀ / I ₂ also increases. The rheological properties of the substantially linear ethylene polymers also differ from the homogeneously branched linear ethylene polymers, which have relatively low, mostly fixed, I ₁₀ / I ₂ ratios.

 It has been found by the inventors that substantially linear ethylene polymers and homogeneously branched linear ethylene polymers (i.e., homogeneously branched ethylene polymers) have unique advantages for use in extruded carpet substrates, especially for commercial and permanent carpet markets. Homogeneously branched ethylene polymers (including substantially linear ethylene polymers in particular) have low solidification temperatures, good adhesion to polypropylene and low modulus with respect to traditional ethylene polymers such as low density polyethylene (LDPE), heterogeneously branched linear low density polyethylene ( LLDPE), high density polyethylene (HDPE) and ultra-low density heterogeneously branched polyethylene (LDPE). As such, homogeneously branched ethylene polymers are used to produce carpet fibers, primary backing materials, adhesive backing materials and optional secondary backing materials. However, homogeneously branched ethylene polymers are, in particular, used as adhesive backing materials for a piercing carpet and non-piercing carpet (e.g., needle-punched carpet) and are especially used for piercing carpets.

 In the present invention, when extruding the back of a carpet to apply adhesive backing material, properly selected substantially linear ethylene polymers and homogeneously branched linear ethylene polymers exhibit good permeability of carpet yarn (fiber bundles) and also provide good consolidation of the fibers in the yarn. When used for piercing carpets, the strength of the pile weave and the wear resistance of the carpet increases when substantially linear ethylene polymers and homogeneously branched linear ethylene polymers penetrate the yarn. Preferably, a pile weave (or pile bundle) strength of 1.5 kg (3.25 pounds) or more, more preferably 2.3 kg (5 pounds) or more, and most preferably 3.4 kg (7.5 pounds) is achieved. ) or more. In addition to improved impregnation of the yarn, the strength of the pile weave can also be increased with an increase in the molecular weight of the polymer. However, the higher molecular weight of the polymer, chosen to increase the strength of the pile weave, is in conflict with the requirement of a lower molecular weight of the polymer, which is usually required for better impregnation of the yarn and good application in the form of an extrusion coating. In addition, higher polymer densities are desirable for improved chemical and barrier resistance, and even higher densities invariably produce stiffer carpets. As such, the properties of the polymer should be selected so that a balance is maintained between the ability to be applied by extrusion and wear resistance, as well as between the chemical resistance and elasticity of the carpet.

 When carpet unfinished products are provided with a backing of properly selected substantially linear ethylene polymers or homogeneously branched linear ethylene polymers, the low flexural modulus of these polymers has the advantages of ease of carpet installation and general carpet handling.

The substantially linear ethylene polymers, in particular when used as an adhesive base material, exhibit improved mechanical adhesion to polypropylene,
which improves the combination and resistance to delamination of various layers of the carpet and components, i.e. polypropylene fibers, fiber bundles, primary backing material, adhesive backing material and secondary backing material when it is optionally used. Therefore, exceptionally good wear resistance and pile weave strength can be obtained. Good durability is especially important in industrial carpet cleaning operations, as Good wear resistance usually improves carpet durability.

 Properly selected substantially linear ethylene polymers can eliminate secondary backing materials and, as such, can provide significant savings in manufacturing costs. In addition, carpets with a base bonded with a substantially linear ethylene polymer or a homogeneously branched linear ethylene polymer can provide a significant barrier to liquid and dust, which improves the hygiene of the carpet.

 An adhesive backing material of a substantially linear ethylene polymer or a homogeneously branched linear ethylene polymer can produce fully recyclable carpet products, especially where the carpet contains polypropylene fibers. In addition, a mixture of a substantially linear ethylene polymer or a homogeneously branched linear ethylene polymer with a fiber grade polypropylene resin can provide an impact resistant recyclable composition that is used for injection molding and other moldings, as well as for reuse in carpet construction, for example, as a material primary base or as a component of a mixture of a polymer composition of an adhesive base material, i.e. polyolefin polymer blends may include polymers with similar chemistry, compatibility, and / or miscibility to provide good processability, but not so much as to provide integral melting.

A preferred homogeneously branched ethylene polymer has a single melting peak between -30 ^° C and 150 ^° C, as determined using differential scanning calorimetry. The most preferred homogeneously branched ethylene polymer for use in the invention is a substantially linear ethylene polymer having:
(a) melt flow ratio I ₁₀ / I ₂ ≥ 5.63
(b) a molecular weight distribution of M _w / M _n as determined by gel permeation chromatography and defined by the equation: (M _w / M _n ) ≤ (I ₁₀ / I ₂ ) - 4.63;
(c) gas extrusion rheology such that the critical shear rate at the onset of surface melt fracture for a substantially linear ethylene polymer is at least 50% greater than the critical shear rate at the onset of surface melt fracture for a linear ethylene polymer, where the linear polymer ethylene has a homogeneously branched distribution of short chain branches and does not have long chain branches, and where the substantially linear ethylene polymer and linear ethylene polymer are at the same time ethylene homopolymers or interpolymers of ethylene and at least one alpha-C _3-20 olefin, and have the same I ₂ and M _w / M _n , and where the corresponding critical shear rates of a substantially linear ethylene polymer are determined for one and the same the same melt temperature using a gas extrusion plastometer;
(d) a single melting peak determined by differential scanning calorimetry (DSC), between -30 ^o C and 150 ^o C.

The determination of the critical shear rate from the point of view of melt fracture, as well as other rheological properties, such as the "rheological processability index" (PP), is carried out using a gas extrusion plastometer (HEP). A Gaeo-extrusion plastometer is described by M. Shida, RN Shroff and LV Cancio, Polymer Engineering Science, Vol. 17, 11, p. 770 (1977) and John Dealy's "Rheometers for Molten Plastics', published by Van Nostrand Reinhold Co. (1982), pp. 97-99. HEP experiments are carried out at a temperature of 190 ^{° C.} under a nitrogen pressure of between about 1.7 and 37.4 MPa (about 250 and about 5500 psi) using a head with a diameter of 0.0754 mm and a screw 20: 1 L / D with an entry angle of about 180 ^o . For the substantially linear ethylene polymers used here PP is the apparent viscosity (in kpoise) of a material measured by the EFG at apparent shear stress of 2.15 x 10 ⁶ dynes / cm (2.19 × 10 ⁴ kg / m ^2). The substantially linear polymer the titylene for use in the invention has a PP in the range of 0.01 kpc to 50 kpc, preferably 15 kpc or less. The substantially linear ethylene polymer used here also has a pp of less than or equal to 70% of that of the linear ethylene polymer (or Ziegler a polymerized polymer, or a homogeneously branched linear polymer, as described in US Pat. No. 3,645,992 (Elston) having I ₂ and M _w / M _n , each 10% of the substantially linear ethylene polymer.

 A plot of apparent shear stress versus apparent shear rate is used to identify the phenomenon of melt fracture and quantify the critical shear rate and critical shear stress of ethylene polymers. According to Ramamurthy, Journal of Rheology, 30 (2), pp. 337-357, 1986, above a certain critical flow rate, the observed irregularities of the extrudate can be broadly classified into two main types: surface melt fracture and bulk melt fracture.

The surface destruction of the melt takes place in conditions of an apparent steady flow and varies from the loss of specular gloss of the film to the sharper “shark skin” shape. Here, as determined using the above HEP, the onset of surface melt fracture (MES) is characterized by the onset of loss of gloss of the extrudate, in which the surface roughness of the extrudate can only be determined at a magnification of 40 x. As described in US Pat. No. 5,278,272, the critical shear rate at the onset of surface melt fracture for substantially linear ethylene interpolymers and homopolymers is at least 50% higher than the critical shear rate at the onset of surface melt fracture of a linear ethylene polymer having substantially the same I ₂ and M _w / M _n .

Volumetric destruction of the melt takes place under conditions of unsteady extrusion flow and varies from regular (alternating roughness and smooth, spiral, etc.) to chaotic distortions. For commercial applicability, to maximize the basic characteristics of the film, coatings and products, surface defects should be minimal, if not absent. The critical shear stress at the beginning of volumetric melt fracture for the substantially linear ethylene polymers used in the invention, especially those having a density of more than 0.910 g / cm ³ , is more than 4 x 10 ⁶ dyne / cm ² . The critical shear rate at the beginning of surface melt fracture (MNRR) and at the beginning of volumetric melt fracture (NORP) will be used here based on changes in the roughness and shape of the extrudates extruded using HEP.

The homogeneous ethylene polymers used in the present invention are characterized by a single DSC melting peak. A single melting peak is determined using a differential scanning calorimeter, standardized with indium and deionized water. The methodology includes samples with a size of 5-7 mg, "first heating" to a temperature of about 140 ^o C, which is maintained for 4 minutes, cooling at a speed of 10 ^o C / min to a temperature of 30 ^o C, which is maintained for 3 minutes, and "second heating" at a rate of 10 ^o C / min to 150 ^o C. The only melting peak is taken from the curve "heat flow - temperature" of the "second heating". The total heat of fusion of the polymer is calculated by the area under the curve.

For polymers having a density of 0.875 g / cm ³ to 0.910 g / cm ³ , a single melting peak may have a “shoulder” or “hump” on the lower side of the melting, which is less than 12%, usually less than 9%, and more typically less than 6% of the total heat of fusion of the polymer. Such an artifact is observed for other homogeneously branched polymers, such as Exact ^™ resins, and differs based on the slope of a single melting peak that varies monotonically through the melting region of the artifact. Such an artifact occurs at a melting point of 34 ^{° C.} , usually 27 ^{° C.} , more typically 20 ^{° C. of a} single melting peak. The heat of fusion inherent in the artifact can be determined separately by special integration of its corresponding area under the heat flow - temperature curve.

), работающем при температуре системы 140^oС. Растворителем является 1,2,4-трихлорбензол, из которого получают образцы 0,3%, маc. растворов для впрыска. Скорость потока составляет 1,0 мл/мин, а объем впрыска составляет 100 мкл.Samples of the entire polymer product and individual polymer components are analyzed using gel permeation chromatography (GPC) on a Waters-150 high temperature chromatograph equipped with three columns of mixed porosity (Polymer Laboratories 10 ³ , 10 ⁴ , 10 ⁵ and 10 ⁶

), operating at a system temperature of 140 ^o C. The solvent is 1,2,4-trichlorobenzene, from which samples of 0.3%, wt. solutions for injection. The flow rate is 1.0 ml / min, and the injection volume is 100 μl.

Molecular weight determination is performed using narrow molecular weight distribution polystyrene standards (from Polymer Laboratories) in combination with elution volumes. Equivalent molecular weights of polyethylene are determined using the appropriate Mark-Houwink coefficients for polyethylene and polystyrene (as described by Williams and Ward, Journal of Polymer Science, Polymer Letters, Vol. 6, p. 621, 1968, with the derivation of the following equation:
M _{poly ethylene} = a x (M _{poly styrene} ) ^b .

In this equation, a = 0.4316 and b = 1.0. The weight average molecular weight M _w and number average molecular weight M _{n are} calculated in the usual manner according to the following general formula:
M _j = (S w _i (M _i ^j )) ^j ,
where w _i is the mass fraction of molecules with M _i , washed out from the GPC column in fraction i, and j = l when calculating M _w , and j = -l when calculating M _n .

The molecular weight distribution of M _w / M _n for the substantially linear ethylene polymers and homogeneous linear ethylene polymers used in the present invention is typically from about 1.8 to about 2.8.

However, it is known that substantially linear ethylene polymers have excellent processability despite having a relatively narrow molecular weight distribution. Unlike homogeneous or heterogeneously branched ethylene polymers, the melt flow ratio I ₁₀ / I ₂ of substantially linear ethylene polymers can vary substantially independently of their molecular weight distribution M _w / M _n .

Suitable homogeneously branched ethylene polymers for use in the present invention include interpolymers of ethylene and at least one alpha olefin obtained by a solution, gas phase or suspension polymerization method, or a combination thereof. The corresponding alpha olefins are represented by the following general formula:
CH ₂ = CHR,
where R is hydrocarbyl radical. Further, R may be a hydrocarbyl radical having from 1 to 20 carbon atoms, and as such the formula includes alpha-C _3-20 α-olefins. Suitable alpha olefins for use as comonomers include propylene, 1-butene, 1-isobutylene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene and 1-octene, as well as other types of comonomers, such as styrene, halogen or alkyl substituted styrenes, tetrafluoroethylene, vinylcyclobutane, 1,4-hexadiene, 1,7-octadiene, and cycloalkenes, for example cyclopentene, cyclohexene and cyclooctene. Preferably, the comonomer is 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene or mixtures thereof, since the adhesive base materials containing higher alpha olefins have a particularly improved toughness . However, most preferably the comonomer is 1-octene, and the ethylene polymer is obtained by a solution method.

The density of a substantially linear ethylene polymer or a homogeneously branched linear ethylene polymer, as determined according to ASTM D-792, does not exceed 0.92 g / cm ³ , and is usually in the range of about 0.85 g / cm ³ to about 0 92 g / cm ³ , preferably from about 0.86 g / cm ³ to about 0.91 g / cm ³ , and especially from about 0.86 g / cm ³ to about 0.90 g / cm ³ .

The molecular weight of a homogeneously branched linear ethylene polymer or substantially linear ethylene polymer is conveniently indicated using a melt index measured in accordance with ASTM D-1238, condition 190 ^{° C.} / 2.16 kg (originally called “condition (E)”, and also named as I ₂ ). The melt index is inversely proportional to the molecular weight of the polymer. So, the higher the molecular weight, the lower the melt index, although the relationship is not linear. The melt index of a homogeneously branched linear ethylene polymer or substantially linear ethylene polymer is generally from about 1 gram / 10 minutes (g / 10 min) to about 500 g / 10 min, preferably from about 2 g / 10 min to about 300 g / 10 minutes, more preferably from about 5 g / 10 min to about 100 g / 10 min, especially from about 10 g / 10 min to about 50 g / 10 min, and most especially from about 25-35 g / 10 min .

Another measurement used to determine the molecular weight of a homogeneous linear ethylene polymer or substantially linear ethylene polymer is conveniently indicated using a melt index measurement according to ASTM D-1238, condition 190 ^° C / 10 kg (originally named as “condition N”, and also named as I ₁₀ ). The ratio of the melt indices I ₁₀ and I ₂ is the melt flow ratio and is denoted as I ₁₀ / I ₂ . For a substantially linear ethylene polymer, the I ₁₀ / I ₂ ratio indicates the degree of long chain branching, i.e., the higher the I ₁₀ / I ₂ ratio, the greater the long chain branching in the polymer. The I ₁₀ / I ₂ ratio of the substantially linear ethylene polymer is not less than 6.5, preferably not less than 7, especially not less than 8. The I ₁₀ / I ₂ ratio of the homogeneously branched linear ethylene polymer is usually less than 6.3.

 Preferred ethylene polymers for use in the present invention have a relatively low modulus of elasticity. Those. ethylene polymer is characterized as having a 2% secant modulus of less than 163.3 MPa (24,000 psi), especially less than 129.3 MPa (19,000 psi), and in particular less than 95.2 MPa ( 14,000 psi) as determined in accordance with ASTM D-790.

Preferred ethylene polymers for use in the present invention are substantially amorphous or completely amorphous. Those. the ethylene polymer is characterized as having a crystallinity percentage of less than 40%, preferably less than 30%, more preferably less than 20%, and most preferably less than 10%, as determined by scanning calorimetry using the equation:
crystallinity percentage = (H _f / 292) x 100,
where H _f is the heat of fusion in J / g.

 A homogeneously branched ethylene polymer may be used alone or may be mixed with one or more synthetic or natural polymeric materials. Suitable polymers for blending with the homogeneously branched ethylene polymers used in the present invention include, but are not limited to, another homogeneously branched ethylene polymer, low density polyethylene, heterogeneously branched LLDPE, heterogeneously branched LDPE, medium density polyethylene, high density polyethylene, grafted polyethylene (e.g., heterogeneously branched low density polyethylene grafted with extrusion maleic anhydride, or ultra low density polyethylene with extruded by maleic anhydride), ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, polystyrene, polypropylene, polyester, polyurethane, polybutylene, polyamide, polycarbonate, rubbers, ethylene-propylene styrene polymers, ethylene polymers and vulcanizates.

 The necessary blending of various polymers can conveniently be carried out by known techniques, including, but not limited to, extrusion melt blending, dry blending, roll blending, melt blending such as Banbury blending, and multi-reactor polymerization.

Preferred mixtures include a homogeneously branched ethylene polymer and a heterogeneously branched ethylene-alpha-olefin interpolymer in which the alpha-olefin is an alpha-C _3-8 -olefin obtained using two reactors operating in parallel or in series with the different catalyst systems used in each the reactor.

 Multi-reactor polymerizations are described in concurrently-filed US applications, per. 08/544497 of October 18, 1995; and 08/327156 of October 21, 1994. However, preferred multi-reactor polymerizations contain non-adiabatic closed loop solution reactors as described in provisional US patent applications per. 60/01496 and 60/014705, both of April 1, 1996.

 A number of resin properties, processing conditions, and equipment designs are described for extruded carpet systems that provide characteristics similar to or better than the above latex and polyurethane systems.

 Figure 1 shows the piercing carpet 10. The piercing carpet 10 is made of the material of the primary base 11 with yarn 12 sewn through it; the adhesive backing material 13, which is in direct contact with the back surface of the material of the primary backing 11, essentially encapsulates the yarn 12 and impregnates the yarn 12 and binds the individual fibers of the carpet; optional secondary backing material 14 applied to the back surface of the adhesive backing material 13.

In FIG. 2 shows an extrusion coating line 20 for producing carpet 70. Line 20 includes an extruder 21 equipped with a slit head 22, a compression roll 24, a cooling roll 23, an exhaust hood 26, a feed roll of a finished product 28, and a preheater 25. As shown, the compression roll preferably equipped with a vacuum slot 29 for supplying a vacuum of about 60 ^o or about 17% of its circumference and is equipped with a vacuum pump 27. The slot die 22 dispenses an adhesive backing material in a semi-molten polymerase canvas 30 on the unfinished product 40 with the polymer canvas 30 to the cooling roll 23, and the unfinished product 40 to the optional vacuum roll 24. As shown, the optional secondary backing material 50 is applied to the polymer canvas 30. The point where the crimp roll 24 and the cooling roll 23 close together, called clamp 60.

 The present invention is used in the manufacture of carpets with facial yarn made of various materials, including, but not limited to, polypropylene, polyamide, wool, cotton, acrylate, polyester and polytrimethylene terephthalate (PTT). However, since one of the objectives of the present invention is to provide a recyclable carpet, such as, for example, a 100% polyolefin carpet, the most preferred yarn contains a polyolefin, more preferably polypropylene. Most preferably, the yarn used in the present invention is 2750 denier air-woven polypropylene yarn, such as manufactured by Shaw Industries, Inc. and sold under the brand name "Permacolor 2750 Type 015".

 A preferred primary base material comprises a polyolefin, more preferably polypropylene. Most preferably, the primary backing material is a slotted polypropylene film sheet, such as supplied by Atoso or Synthetic Industries. Alternatively, other types of primary backing materials may also be used. Although other materials such as polyesters or polyamides can be used for the primary backing material, it is preferable to use a polyolefin, so that the goal is to obtain a carpet made entirely of polyolefins. In addition, polypropylene primary base materials are usually lower cost.

 The method of flashing or needle punching the yarn is not critical to the present invention. Thus, any carpet-sewing and needle-piercing equipment and seam models can be used. Alternatively, it doesn’t matter if the stitched yarn loops remain uncut to produce a knit weave; cutting can make a split pile; or cutting, partial cutting and non-cutting to make the facial texture, known as trimmed tips.

 After the yarn is sewn or needle-pierced into the primary backing material, the unfinished product is usually rolled on the back side of the primary backing material facing out and held until it is transferred to the backing line.

In a preferred embodiment, the unfinished article is cleaned or washed before the adhesive backing material is extruded onto it. In particular, yarn that is sewn or needle-pierced to make a carpet often has various amounts of processing aids, most often oily or waxy chemicals, known as finishing chemicals remaining on it from yarn manufacturing processes. It has been found that it is preferable to remove or replace all or substantially all of these processing aids before extruding the adhesive backing material onto the back surface of the primary backing material. The method of pre-cleaning or washing includes passing the unfinished product through a bath containing an aqueous solution of detergent at a temperature of about 64-70 ^o C (for example, 67 ^o C). Suitable detergents include but are not limited to this STA, which is available from American Emulsions. After the technological stage of washing with detergent, the unfinished product is dried and preheated. Drying can be carried out at a temperature of from about 108 ^{° C.} to about 112 ^{° C.} (for example, 110 ^{° C.} ) for about 1.8-2.2 minutes (for example, 2 minutes).

Another preferred method of cleaning or rinsing involves the use of a wet vacuum cleaning system that first distributes room temperature water or heated water (optionally containing either detergent or cleaning solution) to the side of the primary backing material of the unfinished product, and then vacuuming the water and process residues sequentially additives. The wet vacuum system is suitably fitted with a dispensing and vacuum adapter or head so that the entire width of the unfinished product can be wet evacuated at least once on the continuous extrusion coating line. After the technological stage of wet evacuation, the unfinished product is accordingly dried and / or preheated. Suitable detergents, cleaning solutions or cleaning concentrates for use in the wet evacuation method include, but are not limited to, aqueous alkaline solutions, for example, consisting of tetrasodium salt of ethylenediaminetetraacetic acid. One suitable wet vacuum cleaning system is the Rinsevac ^™ carpet cleaning system, and one suitable cleaning concentrate is the Rinsevac ^™ industrial carpet cleaner, both supplied by Blue Luster Products, Inc., Indianapolis, In.

 Other suitable methods of the present invention for cleaning or rinsing processing aids adapted to an extrusion coating line, such as, for example, the method shown in FIG. 2, include steam cleaning, evaporation at elevated temperatures and / or under vacuum, and chemical washing with an unfinished solvent products.

 It is also assumed that the use of polyolefin waxes (to a greater extent than traditional organic and mineral oils) as processing aids will provide improved characteristics of the adhesive base material in it or at least meet the requirements of cleaning or washing. Nevertheless, it has been established by practitioners that the requirements for cleaning or washing may vary depending on the amount and specific type of processing aids present, i.e. higher quantities of processing aids and / or higher molecular weight processing aids may require a more consistent cleaning or rinsing technology, such as, for example, multi-stage cleaning or rinsing using concentrated detergent solutions based on softened or deionized water. It has been found in practice that the cleaning and washing requirements for the effective removal or replacement of processing aids can be more extensive than conventional washing or cleaning procedures carried out for cosmetic or decorative purposes or carried out for the simple removal of loose fibers, primary backing material or other scraps, which is usually is the result of flashing, needle punching and / or cutting operations.

 In another aspect of the present invention, the unfinished product is coated with an aqueous primer material either as a final base, or, preferably, before extruding an adhesive base material onto it. Particles in this dispersion can be made of various polyolefin materials, such as ethylene acrylic acid copolymer (EAA), ethylene vinyl acetate copolymer (EVA), polypropylene or polyethylene (for example, low density polyethylene (LDPE), linear low density polyethylene (LLDPE ) or a substantially linear ethylene polymer or mixtures thereof). Currently, polyethylene particles are preferred. Most preferred are the polyethylene particles sold by Quantum USI Division under the brand name "Microthene FN500".

 Preferably, the polyolefin particles are present in an amount between about 10 and about 75 May. dispersions, more preferably between about 20 and about 50%, and most preferably between about 25 and about 33%.

 The size of the polyolefin particles is important both to ensure good dispersion and to ensure that the particles penetrate the yarn and the primary backing to ensure good wear resistance. Preferably, the average particle size is between about 1 and about 1000 microns, and more preferably between about 5 and 40 microns. The most preferred polyethylene particles described above have an average particle size of from about 18 to about 22 microns (e.g., 20 microns).

Preferably, the polyolefin particles have a Vicat softening point (as defined in accordance with ASTM D-1525) between about 50 and about 100 ^{° C.} , and more preferably between about 75 and 100 ^° C. The most preferred polyethylene particles mentioned above have a temperature Vicat softeners from about 80 ^{° C.} to about 85 ^{° C.} (e.g., 83 ^{° C.} ).

When polypropylene particles are used, they preferably have a melt flow rate (ASTM D-1238, condition 210 / 2.16) between about 1 and about 80, most preferably between about 60 and about 80. When polyethylene particles are used, they preferably have a melt index I ₂ (ASTM D-1238, condition 190 / 2.16) between about 1 and about 100 g / 10 min, and more preferably between about 20 and about 25 g / 10 min. The most preferred polyethylene particles mentioned above have a melt index I _{2 of} 22 g / 10 min.

 A copolymer of ethylene with acrylic acid (EAA) can be used for polyolefin particles, preferably in combination with polyethylene or polypropylene particles. It has been established that EAA can increase the adhesion of soil to yarn and the primary base, as well as to a thermoplastic sheet extruded onto it.

 The aqueous dispersion preferably contains other ingredients. For example, a surfactant is preferably included to maintain the polyolefin particles in a dispersed state. Suitable surfactants are nonionic, anionic, cationic and fluorine-containing surfactants. Preferably, the surfactant is present in an amount between about 0.01 and about 1 mass. % in relation to the total mass of the dispersion. More preferably, the surfactant is anionic. Most preferably, the surfactant is supplied by Ciba-Geigy under the trademark "Igepal C0430" and is present in an amount of 0.1 wt.% With respect to the total weight of the dispersion.

 Preferably, a thickening agent is also included to provide an appropriate dispersion viscosity. Preferably, the thickener is selected from the group consisting of sodium and ammonium salts of polyacrylic acid, and is present in an amount of between about 0.1 and about 2 wt.% With respect to the total weight of the dispersion. Most preferably, the thickening agent is a polyacrylic acid salt, such as that sold by Sun Chem International under the trademark "Print Gum 600" and present in an amount of about 0.8% by weight relative to the total weight of the dispersion.

Preferably, the dispersion viscosity, measured on a Brookfield RVT viscometer, is between about 3000 cps (centipoise) at 20 rpm with spindle 5 and about 50,000 cps at 2.5 rpm with spindle 5, measured at 23 ^o C. Most preferably, the viscosity of the dispersion is between about 10,000 and 2,000 cP at 2.5 rpm with spindle 5.

 In addition, the dispersion preferably includes an antifoam. Preferably, the antifoam is a non-silicone antifoam and is present in an amount of between about 0.01 and about 1.0 wt.% With respect to the total weight of the dispersion. Most preferably, the antifoam is that supplied by LENMAR Chemical Corporation under the brand name "MARFOAM N-24A" and is present in an amount of about 0.1 wt.% With respect to the total weight of the composition.

 Preferably, the aqueous dispersion further includes a dispersion enhancer, such as pulverized silica, which has been found to act as an agent that enhances the compatibility of the dispersion, resulting in the use of larger polyolefin particles. Preferably, pulverized silica is present in an amount of between about 0.1 and about 0.2 wt. % in relation to the total mass of the dispersion. Most preferably, the pulverized silica is that supplied by DeGussa under the brand name "Aerosil 300".

 An aqueous dispersion of polyolefin particles can be obtained in various ways. Preferably, the ingredients are added to the water in the following order: surfactant, antifoam, polyolefin, thickener. The mixture is then mixed in a homogeneous mixer, preferably by high shear mixing, until all the lumps are dispersed, usually within about 8-12 minutes (e.g. 10 minutes).

 The dispersion can be applied to the carpet in various ways. For example, the dispersion may be applied directly by a roll over roll applicator, or by a squeegee. Alternatively, the dispersion may not be applied directly, for example, with a tray applicator. Preferably, the roll over roll applicator is used with an upper roll rotating at about 22-27% linear speed (e.g. 25% linear speed).

The amount of dispersion applied and the particle concentration may vary depending on the desired process parameters and product parameters. Preferably, the amount of dispersion applied and the concentration of particles are selected to apply between about 141.5 and about 424.4 cm ³ / m ² (between about 4 and about 12 ounces / sq. Yards) of the carpet. Most preferably, this is achieved using a dispersion containing about 50 wt. % polyolefin particles (relative to the total weight of the dispersion) and application between about 283 and about 353.7 cm ³ / m ² (between about 8 and about 10 ounces / sq. yard) of the dispersion.

After applying the dispersion, heat is applied to the back side of the primary substrate so as to dry the dispersion and at least partially melt the particles. As a result, loops of yarn are bonded to the primary backing. Preferably, heat is supplied as the product passes through the furnace. Such a furnace is preferably set at a temperature between about 100 and about 150 ^{° C.} , and the product is consumed between about 2 and about 5 minutes of passing through the furnace. In addition, since the goal is to at least partially melt the particles, the temperature of the furnace is set between about 5 and 75 ^{° C.} above the Vicat softening temperature of the polyolefin particles.

 After dispersion treatment of the polyolefin particles, the carpet may be used as is, or, more preferably, may have an additional base applied thereon. Additional substrates can be applied in various ways with a preferred method as described above, including the use of an extruded sheet of a thermoplastic material, preferably a homogeneously branched ethylene polymer, as described above, onto which a conventional secondary base is laminated. In particular, the molten thermoplastic material is preferably extruded through the die so as to produce a sheet as wide as a carpet. The molten extruded sheet is applied to the back of the primary backing of the carpet. Since the sheet is molten, the sheet takes the form of loops of yarn and additionally serves to fasten the loops in the primary basis.

The composition of the extrusion coating equipment includes a single layer T-type die, a single-slot die for coextrusion coating, a double-slot die for coextrusion coating, and multi-stage extrusion coating. Preferably, the extrusion coating equipment is designed to apply a total coating weight of between about 141.5 and about 1061.1 cm ³ / m ² (between about 4 and about 30 ounces / sq. Yard), with most preferred being between about 636.7 cm ³ / m ² (approximately 18 ounces / sq. Yard) and approximately 778.1 cm ³ / m ² (approximately 22 ounces / sq. Yard), for example, 707, 4 cm ³ / m ² ( 20 ounces / sq. Yards).

 The thickness of the unstretched compressed adhesive adhesive backing material measured in another way is in the range of about 0.15 to about 2 mm (about 6 to 80 mils), preferably about 0.25 to about 1.52 mm (about 10 to about 60 mils), more preferably from about 0.38 to about 1.27 mm (from about 15 to about 50 mils), and most preferably from about 0.51 to about 1.02 mm (from about 20 to about 40 mil).

 The linear speed of the extrusion process depends on what kind of polymer is extruded, what kind of equipment is precisely used, and how much polymer is applied. Preferably, the linear velocity is between about 5.5 and about 76.2 m / min (between about 18 and about 250 ft / min), more preferably between about 24.4 and about 67.1 m / min (between about 80 and about 220 ft / min), most preferably between about 30.5 and about 61 m / min (between about 100 and about 200 ft / min).

The melt temperature of the extrusion coating mainly depends on the particular extrudable polymer. When using the most preferred substantially linear polyethylene as described above, the extrusion coating melt temperature is greater than about 232 ^° C (450 ^° F), preferably greater than or equal to about 260 ^° C (500 ^° F), or between about 232 ^° C (approximately 450 ^° F.) and about 343 ^{° C.} (650 ^° F.), more preferably between about 246 ^{° C.} (475 ^° F.) and about 316 ^{° C.} (about 600 ^° F.), most preferably between about 260 ^{° C.} and about 288 ^o C (between about 500 and about 550 ^o F).

 Preferably, two resin layers are extruded (each layer containing a different resin), with the layer deposited directly on the back side of the primary backing material (first layer) having a higher melt index than the second layer that is applied to the back side of the first layer. Since the first layer is located on encapsulated and impregnated yarn, it must have a sufficiently high melt index (sufficiently low melt viscosity) to provide encapsulation and impregnation of the yarn. The second layer is usually not located on the encapsulated and impregnated yarn and can be used as the bottom surface of the carpet or to facilitate the application of optional secondary backing material. For both of these purposes, it is preferable to have a lower melt index to provide higher strength after cooling. Moreover, since it is not suitable for encapsulation or impregnation of fiber bundles, a lower quality resin and / or with less precisely controlled properties can be used in the second layer. In a preferred embodiment, the second layer is recycled.

 In addition, the first and second layers may consist of polymers of various chemical compositions or compositions. For example, the first layer may consist of an adhesive polymer (as an additive or as a composition of the entire layer), such as (but not limited to) a copolymer of ethylene with vinyl acetate, a copolymer of ethylene with acrylic acid or a grafted copolymer of ethylene and maleic anhydride (preferably substantially linear polymer of ethylene with extrusion grafted maleic anhydride or high density polyethylene with extrusion grafted maleic anhydride), the second layer may consist of a non-polar polymer such as a homogeneously branched second ethylene polymer, low density polyethylene or ultra low density polyethylene. Alternatively, the first layer may consist of a non-polar polymer, and the second layer may consist of an adhesive polymer.

Preferably, the first layer has a melt index I ₂ between about 30 and between about 175 g / 10 min, and the second layer has a melt index I ₂ between about 1 and about 70 g / 10 min. Most preferably, the first layer has a melt index of 1 ₂ between about 30 and about 70 g / 10 min, and the second layer has a melt index of I ₂ between about 10 and about 30 g / 10 min.

 It is also preferable to extrude two layers of the same polymer composition so as to better control the thickness or weight of the resin applied to the carpet. In alternative embodiments, three or more layers of resin may be extruded onto the back surface of the primary backing material to obtain higher coating weights and / or to obtain a more gradual transition between the deposited first and last layer. Preferably, the double slit head is used to apply two layers. Alternatively, two or more extrusion plants or a single-slot coextrusion die may be used to deposit these two or more layers.

 Another aspect of the present invention is the use of modified homogeneously branched ethylene polymers. In particular, in some aspects of the invention, at least one homogeneously branched ethylene polymer that is used as an adhesive backing material, primary backing material or yarn, preferably as an adhesive backing material, is modified by introducing at least one adhesive polymer additive. Suitable adhesive polymer additives include polymer products consisting of (1) one or more ethylenically unsaturated carboxylic acids, anhydrides, alkyl (esters) and partial esters, for example, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid, crotonic acid and citraconic acid, citraconic anhydride, succinic acid, succinic anhydride, methyl hydrogen hydromaleate and ethyl hydrogen hydrogen malate; esters of ethylenically unsaturated carboxylic acids, for example ethyl acrylate, methyl methacrylate, ethyl methacrylate, methyl acrylate, isobutyl acrylate and methyl fumarate; unsaturated esters of carboxylic acids, for example vinyl acetate, vinyl propionate and vinyl benzoate; and ethylenically unsaturated amides and nitriles, for example acrylamide, acrylonitrile, methacrylonitrile and fumaronitrile; and (2) one or more ethylenically unsaturated hydrocarbon monomers, such as aliphatic alpha olefin monomers, for example ethylene, propylene, butene-1 and isobutene; conjugated dienes, for example butadiene and isoprene; and monovinylidene aromatic carbocyclic monomers, for example styrene, alpha-methyl styrene, toluene and t-butyl styrene. Suitable adhesive polymer additives can be conveniently prepared by known methods, such as, for example, interpolymerization or polymerization followed by chemical or extrusion grafting. Suitable grafting methods are described in US Pat. Nos. 4,762,890, 4,927,888, 4,230,830, 3,873,643 and 3,882,194.

 Preferred adhesive polymer additives for use in the present invention are maleic anhydride inoculations in which maleic anhydride is grafted onto an ethylene polymer in a concentration of from about 0.1 to about 5.0 wt. %, preferably about 0.5-1.5 wt.% The use of grafts of maleic anhydride on ethylene polymer as an adhesive polymer additives in the present invention significantly improves the characteristics and operating range of extrusion-applied homogeneous branched ethylene polymers as an adhesive base material, especially for a polar polymer, such as, for example, but not limited to, polyamide and polyester coated carpets. The improvement relates to significantly higher wear resistance and pile weave strength. The improvement is unexpected in that, as is well known, grafted adhesives require increased melt or half-melt contact times for improved performance and function as interlayer adhesives for films and coatings, where there is a continuous substrate as opposed to the discontinuous interface existing in the carpet structure.

Preferred ethylene polymers for use as the graftable host polymer include low density polyethylene (LDPE), high density polyethylene (HDPE), heterogeneously branched linear low density polyethylene (LLDPE), homogeneously branched linear ethylene polymers and substantially linear ethylene polymers. Preferred ethylene host polymers have a polymer density of greater than or equal to 0.915 g / cm ³ and, most preferably, greater than or equal to 0.92 g / cm ³ . Essentially linear polymers of ethylene and high density polyethylene are preferred host polymers.

In this aspect of the present invention, the adhesive polymer additive is introduced into the homogeneously branched ethylene polymer in an amount of from about 0.5 to about 30 wt.%, Preferably from about 1 to about 20 wt.%, More preferably from about 5 to about 5. 15 wt. %, relative to the total weight of the polymer. For preferred grafting of maleic anhydride on an ethylene polymer, administration should provide a final concentration of maleic anhydride in the range of about 0.01 to about
0.5 wt.%, Preferably from about 0.05 to about 0.2 wt.%, Relative to the total weight of the polymer.

Ancillary equipment such as a pre-heater may be used. In particular, a heater, such as a convection oven or infrared panels, can be used to heat the rear of a finished product before the adhesive backing material is extruded onto it. It was found that encapsulation and impregnation of bundles of yarn can be increased. Preferably, the pre-heater is an infrared installation positioned between about 200 and about 1,500 ^{° C.} , and the unfinished product is held with this heating for between about 3 and about 30 seconds. Most preferably, the heater is installed at about 1000 ^{° C.} , and the unfinished product is held with this heating for about 5-7 seconds (for example 6 seconds).

In addition to or as an alternative to preheating, the method of the invention can also use the sequential soaking step to increase the melt time for the adhesive backing material, with the result of encapsulation and impregnation of the yarn or fiber bundles with the adhesive backing material. Preferably, after applying the adhesive base material to the unfinished product, it is heated in a convection oven or infrared at a temperature between about 200 and about 1500 ^{° C.} for between 3 and 30 seconds, most preferably at 1000 ^{° C.} for about 7 seconds ( e.g. 6 s).

As another part of the auxiliary or optional equipment, a vacuum crimp roll may be used to feed the extrudate of the adhesive backing material (i.e., a semi-molten or molten polymer web) onto an unfinished product. In the operation of extrusion coating with correctly selected equipment, the pile front side of the unfinished product is facing the vacuum crimp roll, and the polymer canvas is fed to the back surface of the primary base material of the unfinished product. The vacuum roll 24 (which is shown in FIG. 2 and supplied by Black Clawson Corporation) is suitable for vacuum drawing a canvas of adhesive base material. The vacuum crimping roll 24 can be modified from a traditional crimping roll, in which part of the hollow interior of the roll is partitioned, separated and connected to the external vacuum pump 27 to provide a vacuum surface. The surface of the vacuum part is perforated, but processed flush and continuously with the rest of the surface of the roll. Corresponding vacuum crimping rolls can have a full 360 ^o vacuum surface; however, a vacuum surface of from about 10 to about 180 ^° is preferred, most preferably about 60 ^° . To effectively draw the adhesive backing material on an unfinished product and maximize the impregnation of yarn (or fiber bundles), a vacuum of more than 3.7 Pa (15 inches H ₂ O) is established, preferably more than or equal to 6.1 Pa (25 inches H ₂ O) or between about 3.7 and about 12.3 Pa (between about 15 and about 50 inches of H ₂ O), preferably between about 4.9 and about 11.1 Pa (between about 20 and about 45 inches of H ₂ O).

 The length of time during which the unfinished product is exposed to vacuum, mainly depends on the linear speed of the coating by extrusion, and the degree of stretching of the canvas of the adhesive base material significantly depends on the degree of vacuum and porosity of the unfinished product. As such, higher vacuum levels are required for higher linear extrusion coating rates and / or a denser unfinished product to efficiently draw the adhesive backing material.

 In addition to, or as an alternative to, a vacuum crimp roll, a device with excessive high air pressure, such as an air squeegee or knife, can also be used to pump the adhesive backing material onto the back surface of the primary backing material. Preferably, the overpressure device is installed so as to provide an air pressure of more than 0.14 MPa (20 psi), preferably more than or equal to 0.27 MPa (40 psi), more preferably more than or equal to 0.41 MPa (60 psi) or between about 0.14 and about 0.82 MPa (between about 20 and about 120 psi), most preferably between about 0.20 and about 0 54 MPa (between about 30 and about 80 psi). Preferably, the air overpressure device is placed on the extrusion coating clamp, passes through the entire width of the polymer web, is placed behind the polymer web to the cooling roll so that the polymer web is fed onto the unfinished product and the polymer web is pressed into the yarn (or fiber bundles).

 The extrudable polymer (s) may either be used pure or may have one or more added additives. A preferred additive is an inorganic filler, more preferably a high heat content inorganic filler. Examples of such fillers include, but are not limited to, calcium carbonate, aluminum trihydrate, talc, barite. High heat fillers are considered to be an advantage in the invention since such fillers allow the extrudate to remain at elevated temperatures for longer, with the advantage of providing improved encapsulation and impregnation. Those. usually, fillers are introduced into carpet backing materials only to add mass (for example, as cheaper additives) or to impart insulating or sound-absorbing characteristics. However, the authors found that inorganic mineral fillers, which have a high heat content, unexpectedly improve the encapsulation and saturation of the yarn, which, in turn, improves the characteristics of wear resistance and pile weave strength of the samples of the extrusion coated carpet.

Preferably, a high heat filler is added at a concentration of between about 1 and about 75% wt. total extrudate, more preferably between about 15 and about 60 wt.%, and most preferably between about 20 wt.% and 50 wt.%. Such fillers have a specific heat content of more than or equal to 1.8 J • cm ³ / ^o C (0.4 cal • cm ³ / ^o C), preferably more than or equal to 2 J • cm ³ / ^o C (0.5 cal • cm ³ / ^o C), more preferably 2.5 J • cm ³ / ^o C (0.6 J • m ³ / ^o C), and most preferably more than or equal to about 2.9 J • cm ³ / ^o C (about 0.7 cal • cm ³ / ^o C). Typical examples of high heat fillers for use in the present invention include (but are not limited to) limestone (mainly CaCO ₃ ), marble, quartz, silica and barite (mainly BaSO ₄ ). Fillers with high heat content should be crushed or crystallized to a size that can be conveniently introduced into the melt stream of the extrusion coating. Corresponding particle sizes range from about 1 to about 50 microns.

If a foamed base is desired on the carpet, a foaming agent may be incorporated into the adhesive base material and / or optional secondary material. If blowing agents are used, they are traditional heat-activated blowing agents, such as azodicarbonamide, toluenesulfonylsemicarbazide and oxybis (benzenesulfonyl) hydrazide. The amount of blowing agent to be added depends on the degree of foaming required. Typical blowing agent levels are between about 0.1 and about 1.0 wt.%
An explosion in the present invention is carried out with limited expansion of the adhesive backing material in the opposite direction to the primary backing material during the activation of the detonating agent so that the molten polymer is injected into and into the free space of the yarn (or fiber bundles). Explosive adhesive backing material has a compressed unstretched matrix (relative to the foamed backing) and essentially the same thickness (measured from the plane of the back surface of the primary backing material) as would be possible without using an exploding agent. Those. a layer of adhesive base material would be characterized as unexpanded by an exploding agent.

 The blasting agent is selected and introduced into the formulation of the adhesive base material, and the extrusion conditions are selected so that the activation of the blasting agent takes place at the time of pressing, when the adhesive base material is still half-molten or molten. With improved impregnation of yarn achieved using an exploding agent, the carpet exhibits comparatively improved wear resistance. Thus, the use of an explosive agent may allow the use of polymer compositions having low molecular weights, providing improved applicability and maintaining high wear resistance (i.e., comparable with adhesive materials based on high molecular weight polymer compositions). An effective amount of an explosive agent is between about 0.1 and about 1.0 wt.% With respect to the total weight of the adhesive base material.

 Conventional blowing agents or any material that typically acts as a blowing agent can be used as the blasting agent in the present invention, ensuring that the expansion of the matrix of adhesive base material is significantly limited or difficult when the material is activated so that the molten polymer is pumped inward and into the free space of yarn (or fiber bundles), and there is no significant expansion of the adhesive base material, as a result of using digging agent. However, preferably, the detonated adhesive backing material is characterized as having a closed cellular structure, which can be conveniently identified by micrographs at 50x magnification.

Other additives may also be included in the adhesive base material to such an extent that they do not interfere with the detected improved properties. For example, antioxidants such as sterically hindered phenols, sterically hindered amines and phosphites can be used. Suitable antioxidants include Irganox ^® 1010 from the company Ciba Geigy, which is a hindered phenol and Irgafos ^® 168 from the company Ciba Geigy, which is a phosphite. Other possible additives include anti-caking additives, pigments and dyes, antistatic agents, antimicrobials (such as quaternary ammonium salts) and cooling roll releasing additives (such as fatty acid amides).

 As noted above and shown in FIG. 2, the carpet of the invention preferably also includes a secondary backing material. Preferably, the secondary backing material is laminated directly with the extruded layer (s) while the extrudate is still molten after extrusion application. It has been found that this technology can improve the permeability of the extrusion coating into the primary substrate.

 Alternatively, the secondary backing material can be laminated in the last step by reheating and / or remelting at least the outermost part of the extruded layer by coextrusion coating technology using at least two separate extruders. In addition, the secondary backing material can be laminated by other means, such as interlaying a layer of polymer adhesive material between the adhesive backing material and the secondary backing material. Suitable adhesive polymeric materials include, but are not limited to, ethylene acrylic acid copolymers (EAA), ionomers, maleic anhydride grafted polyethylene compositions.

The material for the secondary backing material may be a traditional material, such as a woven polypropylene fabric, sold by AMOSO under the trademark Action Bac ^® . This material is primarily interwoven with polypropylene monofilaments going in one direction and polypropylene yarn going in the other direction. More preferably, the secondary backing material used in the present invention is a woven polypropylene fabric with monofilaments running in two directions. A suitable example of such a material is material supplied by AMOSO under the trademark Style 3878. This material has a basis weight of 70.7 cm ³ / m ² (2 ounces / sq. Yard). It has been established that this material with monofilaments running in two directions perfectly provides improved dimensional stability of the carpet.

 In an alternative preferred embodiment, the secondary backing material is a material known as fiber-bundle fabric or “VPT”. The VPT is a tissue that contains the fibers needle-punched into it. Sometimes VPT is used as the primary backing material on a carpet with a low pile weight. In such a carpet, the fibers protrude on the pile side so as to help keep the primary backing material from appearing through the pile. However, in this alternative preferred embodiment, the VPT is used as a secondary backing material with needle-punched fibers protruding from the carpet. It has been found that performing this improves carpet adhesion when installed with pouring adhesive. In particular, the contact surface area of the pouring adhesive is increased, and the protruding fibers contribute to the weaving of the carpet base with the pouring adhesive.

 Alternatively, the secondary backing material may be non-woven fabric. Several types are available, including, but not limited to, melt-spun, wet-wet, melt-blown and air-woven. As noted above, it is preferred that the secondary base is made of a polyolefin to facilitate recycling.

In an alternative preferred embodiment, the non-woven fabric is a melt-spun fabric such as that sold by Don & Low Non-wovens under the trademark "Daltex". Typically, melt-spun fabric is made from extruded and air-spun polymer yarns that are stacked together and then point-wired, for example, with a heated calender roll. The basis weight of such a melt-spun secondary base may vary, preferably between 35 and 80 g / m ² , more preferably between 60 and 80 g / m ² . Most preferably, the base weight is 77-83 g / m (e.g. 80 g / m ² ). One of the factors favoring a larger base mass for the melt-conjugated fabric is that a fabric with a higher base mass of fabric is less suitable to be molten when brought into contact with the molten extruded base.

 It has been found that melt-spun non-woven fabric has the advantage of being used as a secondary backing in the present invention because the porous nature of the fabric increases the surface area of the carpet to adhere the carpet to the floor.

In yet another alternative preferred embodiment, the secondary backing is a woven polypropylene fabric such as Action Bac ^® by the company AMOCO, which is hardened by igloproshivki on one of its side 70.7 cm ³ / m ² (2 ounces / square yard) polypropylene fibers. This needle-stitched fabric is laminated so that the polypropylene fibers are embedded in the adhesive backing layer. As a result, strands of woven polypropylene fabric are aged. It has been shown that this variant has improved adhesive properties compared to the variant without needle-stitched fibers, because without needle-stitched fibers, the strands of woven polypropylene fabric are at least partially embedded in the adhesive base layer. As such, the bonding surface area is reduced. It was also noted that the rear of the carpet obtained in this embodiment was much less abrasive than was found with a traditional latex-based carpet. The carpet is also more elastic than a traditional latex-based carpet. Therefore, this option is preferred for the manufacture of area carpets and the like.

 Other materials may also be used for the secondary base. For example, if an integral lining is desired, polyurethane foam or other cushioning material may be laminated to the back of the carpet. Such bases can be used for wide-woven carpet, as well as for carpet tiles.

 The extruded carpet structure and methods described herein are particularly suitable for the manufacture of carpet tiles. 6 is a cross-sectional view of carpet tile 100 obtained in accordance with the present invention. The yarn 103 is preferably made of polypropylene, sewn into the primary backing 101, which is also preferably made from polypropylene, so as to leave the front pile surface of the carpet 104 on top of the primary backing 101 and the back stitches 105 below the primary backing.

 Applied to the rear of the primary backing 101 and the back stitches 105 is an adhesive layer 107. Preferably, this adhesive layer is made of a polyolefin. More preferably, the adhesive layer is made of ethylene polymers described in detail above. Most preferably, this adhesive layer 107 is made of a substantially linear ethylene polymer with the additives described in Example 194 below.

In a preferred embodiment of the carpet tile, the carpet comprises from about 176.8 to about 7074 cm ³ / m ² (from about 5 to about 200 ounces / sq. Yard) of extruded adhesive backing. More preferably, the tile carpet includes from about 1061 to about 2830 cm ³ / m ² (from about 30 to about 80 ounces / square yard) of extruded base, most preferably 1768 cm ³ / m ² (50 ounces / square yard )

Preferably, the carpet tile carpet receives its extruded base in two runs, i.e. two layers of extruded base are applied. The first run applies a layer 107 in FIG. 6. Preferably, this layer 107 is between about 88.4 and about 3537 cm ³ / m ² (between about 2.5 and 100 ounces / sq. Yard) of extruded polymer, more preferably between about 530.5 and about 1415 cm ³ / m ² (between about 15 and about 40 ounces / sq. yards), and most preferably, 884 cm ³ / m ² (25 ounces / sq. yards). The second run applies layer III. Preferably, the second layer III is about 88.4-3537 cm ³ / m ² (about 2.5-100 ounces / sq. Yard), more preferably between about 530.5 and about 1415 cm ³ / m ² (between about 15 and 40 ounces / sq. Yards).

 The application of the extruded base in two runs provides the opportunity to apply the first and second layers, which have different physical and / or chemical properties. As noted above, it is sometimes preferable to apply a polymer with a higher melt index adjacent to the primary substrate, and a polymer with a lower melt index below. In addition, it is also possible to use an extrudate with a lower filler content in the layer following the primary substrate, and an extrudate with a higher filler content in the layer below. In one preferred embodiment, the layer following the primary base has a filler content of 30 wt. %, and the layer below has a filler content of 60 wt.%. The lower filler content is intended to provide better impregnation of the primary backing and back stitches in the carpet with an extrudate.

In the manufacture of carpet tiles, it is preferable to embed a layer of reinforcing material 109 between the first and second layers of the extruded base. An important property of carpet tiles is dimensional stability, i.e. the ability of a tile to maintain its size and flatness over time. It was found that the inclusion of this layer of reinforcing material increases the dimensional stability of carpet tiles made in accordance with this preferred option. Suitable reinforcing materials include dimensionally and thermally resistant fabrics, such as non-woven or wet-woven fiberglass webs, as well as woven and non-woven thermoplastic fabrics (e.g., polypropylene, polyamide and polyester). Most preferably, the reinforcing layer is a polypropylene non-woven fabric sold by Reemay under the brand name Taurag with a basis weight of 124 cm ³ / m ² (3.5 ounces / sq. Yards). Alternatively, a preferred reinforcing layer is fiberglass canvas supplied by ELK Corp. under the brand name "UltraMat", with a basis weight of 49.5 cm ³ / m ² (1.4 ounces / sq. yard).

 Carpet tiles may include secondary backing fabric 113 below the second layer of extruded backing III. Suitable secondary backing materials include those described above. However, it is currently not preferred to incorporate secondary fabric into carpet tiles.

 7 schematically shows a preferred line 120 for producing carpet tiles according to the present invention. A piece of unfinished product 121, that is, yarn sewn onto the primary backing, is rolled from the roll 123. The unfinished product 121 is passed through the rolls 125 and 127 with the primary backing to the roll 123. A preheater 129 is located between the rolls 125 and 127, as described above.

 The extruder 131 is mounted so as to extrude the polymer backing sheet 135 through the die 133 onto the back of the unfinished product at a point between the roll 127 and the crimp roll 141. The exact location at which the sheet 135 is in contact with the unfinished product may vary depending on linear speed and time , desirable so that the molten polymer remains on the unfinished product before passing between the crimping roller 141 and the cooling roller 143. Currently, it is preferable that the sheet 135 in contact with the unfinished product so that it is on the unfinished product between about 0.5 and about 2 seconds, most preferably about 1 second, before passing between the crimping roll 141 and the cooling roll 143.

 In this highlighted preferred embodiment, the non-woven polypropylene canvas 139 is fed from the roller 137 so as to contact the cooling roller 143 at a point slightly earlier than the crimp roller 141. As a result, the canvas 139, which acts as a reinforcing fabric in the finished carpet tile, is laminated with the unfinished product through the polymer .

 The pressure between the squeeze roll 141 and the cooling roll 143 may vary depending on the force desired to compress the extruded sheet. Most preferably, when the rollers are brought together by an air pressure of 0.41 MPa (60 psi). Furthermore, as described in relation to FIG. 2, it may be desirable to include a vacuum gap in the crimp roll. In addition, a stream of compressed air can also be used to press the extruded sheet into the carpet base.

 The size of the cooling roll 143 and the length of time during which the carpet is rolled can vary depending on the desired degree of cooling in the process. Preferably, the cooling roll 143 is cooled simply by passing water at room temperature through it.

 After passing through the cooling roll 143, the carpet is transferred over the rolls 145 and 147 with carpet tiles to the rolls. The second extruder 149 extrudes a sheet of polymer 153 through its head to the back of the web 139. The point at which the extruded sheet 153 contacts the web 139 may vary as described above.

 If a secondary backing fabric is desired for carpet tile, this fabric can be inserted from the roll, like the number 137 shown so that upon contact it is laminated to the carpet through the extruded sheet 153 when it passes between the roll 155 and the cooling roll 153. So the secondary fabric warp is not preferred for carpet tile designs.

 The carpet passes between the crimp roller 155 and the cooling roller 157. The pressure applied between the two rollers 155 and 157 may be different. Currently, an air pressure of preferably 0.41 MPa (60 psi) is supplied to the crimp roll 155.

 After passing around the cooling roll 157, the carpet passes around the roll 159 and passes over the embossing roll (not shown) to apply the desired pattern to the back of the carpet.

 Although the device shown in FIG. 7, it is preferable to obtain carpet tiles with two layers of extruded warp and a reinforcing fabric between them, the same design can be obtained using a single extrusion head, crimp roll and cooling roll. In particular, the first layer of the extruded base and the reinforcing fabric can be applied in the first run of the line, after which the carpet is folded. The second layer of the extruded base can be applied over the reinforcing fabric in the second run of the same line, after which the carpet is ready for cutting into carpet tiles.

Carpet tiles are usually obtained by obtaining a piece of carpet with a base and then by cutting the carpet into squares of the appropriate size. In the United States, the most common size is a square of 45.7 cm ² (18 square inches). In the rest of the world, the most common is a square measuring 50 cm ² .

 In yet another alternative embodiment, a pressure sensitive adhesive is applied to the bottom surface of the carpet with the base, and the released sheet is turned on. In this way, a “peel and bar” carpet is obtained. This is especially beneficial when the carpet is cut into tiles. Examples of suitable pressure sensitive adhesives include copolymers of ethylene with vinyl acetate and substantially linear ethylene polymers, in the formulation of which tackifiers and polymer waxes have been added. The release sheet may be made from conventional polymers and / or paper products. Preferably, the release sheet is made from a polyester wax formulation.

 It has been found that pressure-sensitive adhesive is better applied directly to the adhesive backing material when the adhesive backing material is still at an elevated temperature from the extrusion coating process. A preferred technology is extrusion lamination of a pressure sensitive adhesive with an adhesive backing material, i.e. application of pressure sensitive adhesive in the clamp. Alternatively, the adhesive backing material may be reheated before applying the pressure sensitive adhesive.

Another preferred embodiment of the present invention, excluding the optional secondary backing material, comprises a combination of the various process steps described herein, together with the use of at least one substantially linear polymer with an effective amount of detonating agent introduced into the first layer of two layers of adhesive base material. A preferred combination of process steps at least comprises precoating with an aqueous polyolefin system; removal of technological additives by washing or cleaning the unfinished product with an aqueous solution of detergent heated to at least 67 ^o C; drying and preheating the unfinished product by exposure to infrared radiation set at about 1000 ^o C for about 1-6 s; extrusion of an adhesive base material onto the back of a preheated washed primary base material using extrusion melt temperatures greater than or equal to 324 ^° C (615 ^° F); processing the canvas of a semi-molten or molten adhesive base material with a vacuum of more than 9.8 Pa (more than 40 inches of H ₂ O) at the extrusion coating clamp; treating the semi-molten or molten base material with excess air pressure from a device installed at more than 0.41 MPa (60 psi) at the extrusion coating clamp; activation of an explosive agent at an extrusion coating clamp; and thermal impregnation of the carpet when it is treated with infrared radiation set at 1000 ^{° C.} for about 1-6 seconds.

 Various variants of the present invention have been evaluated and in individual cases compared with existing options. However, the examples shown should not be a method of limiting the present invention to such examples.

EXAMPLES
Key indicators identified for various examples include: pile strength, wear resistance, Velcrow test, elasticity and lamination strength. The determination of the strength of the pile weave was carried out in accordance with ASTM D-1335-67.

 The elastic moduli of the ethylene polymers used in the present invention were determined in accordance with ASTM-790.

 Wear resistance was based on a quality assessment during the Velcrow Fluff test. In this test, a roll of 51 mm (2 in.) In diameter and 0.91 kg (2 lb) in weight, covered with a pile side of the Velcrow pattern, was passed 10 times over the face of the coated carpet samples. The flapper on a worn carpet is then compared with a set of carpet patterns and evaluated on a 10-point scale, where 10 means zero fluff.

 The assessment of elasticity was also based on a qualitative assessment.

 The determination of lamination strength was based on a manual qualitative assessment, where a “good lamination” rating is given if the different layers of the carpet sample cannot be torn off manually (ie separating the adhesive backing material from the primary backing material), while the rating is “poor lamination” given if the layers are peeling.

Aachen test was used to determine the dimensional stability of carpet tiles. The Aachen test used here is the ISO 2551 test method. Briefly, carpet tiles are first measured in the machine and transverse directions, then aged when heated at 60 ^° C (140 ^° F) for 2 hours and in a humid environment (immersed in water for 2 h). Carpet tiles are dried for 16 hours in an oven. Then the tiles are placed in the conditioning chamber for 48 hours, after which each tile is measured in machine and transverse directions. The results are given in terms of the percentage change in the original sizes.

 Table 1 provides a list of various ethylene polymers used to produce samples of various examples.

Table 2 summarizes the data on polymers, extrusion conditions and the results of characterization of carpet samples for examples 1-8 of the invention and comparative runs 9-12. The extrusion coating equipment consisted of a Black Clawson two-extruder coextrusion line equipped with a primary extruder with a screw diameter of 89 mm (3 ^1/2 inches) having a L / D of 30: 1, and a secondary extruder with a screw diameter of 64 mm (2 ^1/2 inches) with L / D 24: 1. For these examples, only the large extruder operated at 90 rpm (112.5 kg / h). A die with a 760 mm gap was attached to the extruder and narrowed to 690 mm with a 0.51 mm gap (20 mils) of the die and with an air-exhaust gap of 152 mm (6 inches). The pressure of the crimp roll was set at 0.58 MPa (85 psi), and the cooling roll was adjusted at 15.6 ^° C (60 ^° F). The specified extrusion temperatures, linear speed and coating thickness are shown in table 2.

Pieces of an unfinished polypropylene product (919.6 cm / m (26 ounces / sq. Yard)) (pierced, knitted direct weave products supplied by Shaw Industries under the Volunteer brand) were cut and layered on kraft paper for each example, and the test resins were extruded onto the back of unfinished products. A secondary backing material (99 cm ³ / m ² (2.8 ounces / sq. Yards)) of woven polypropylene canvas (known as Action Bac ^® , supplied by Amoco Chemical Company, separation of fabrics and fibers) was applied to the back of unfinished products after the location of the extrudate in the head and after the crimp rolls form a laminate structure. Figure 2 shows the method of coating by extrusion and the sequence of application by extrusion of an adhesive base material followed by the application of an optional secondary base material. In some cases, the pieces of the unfinished product were first preheated in a convection oven at 93 ^° C (200 ^° F) for 30 minutes. After the coated samples were aged for 24 hours at room temperature and 70 A relative humidity, the pile weave strength, wear resistance, and delamination were determined.

 Examples 1-8 of the invention show that homogeneously branched ethylene polymers produce carpet samples with good elasticity and good cohesion of carpet components, and that pile strength and wear resistance depend on processing conditions. The extruded two high-pressure LDPEs, a heterogeneously branched LLDPE and a heterogeneously branched LDPE (comparative runs 9-12) produce relatively hard carpets and relatively poor cohesion of the carpet components.

 One indicator of poor component cohesion was the relatively low adhesion of the base material to the primary base material. Another indicator was the relatively low impregnation of yarn (or fiber bundles) with extrusion coating resins of LDPE, LLDPE and PEUNP.

 Table 3 summarizes the data on polymers, extrusion conditions and the results of determining the characteristics of carpets for examples 13-22 of the invention.

 In these examples, the same extrusion equipment, extrusion conditions, and unfinished products are used as indicated for Examples 1-12.

Examples 13 ÷ 22 of the invention show the effect of coating thickness and extrusion temperature on the characteristics of the carpet base. In some aspects of the present invention, the coating thickness is greater than 0.18 mm (7 mil), preferably greater than or equal to 0.38 mm (11 mil), more preferably greater than or equal to 0.45 mm (15 mil), and most preferably more than or equal to 0.56 mm (22 mil), it is preferable for an extrusion melt temperature of more than 288 ^o C (550 ^o F), preferably more than or equal to 302 ^o C (575 ^o F), more preferably more than or equal to 316 ^o C (600 ^° F.), and most preferably, more or more 324 ^{° C.} (615 ^° F.).

Practitioners note that the temperature of the extrusion melt and the linear extrusion rate are inversely proportional. Those. lower extrusion temperatures usually require slower linear extrusion speeds to achieve good yarn penetration. Practitioners also noted that at elevated temperatures may be required heat stabilizing additives such as Irganox ^® 1010 and Irgafos ^® 168 (both supplied Ciba-Geigy company), to achieve the full superiority of the present invention, such as, e.g., impregnability yarn (or fiber bundles) adhesive base material more than 40%. Practitioners also note that excessive chemical stabilization can adversely affect the characteristics of the hood, so the choice of additive and concentration must be balanced with the requirements of the hood and the requirements of the impregnation. However, in the general case, higher additive concentrations will be required at higher melt extrusion temperatures.

Table 4 summarizes the data on polymers, extrusion conditions and the results of characterization for examples 23-54. In these tests, the extrusion coating equipment consisted of a Black Clawson extruder, model 435, with a diameter of 89 mm (3 ^1/2 inches), equipped with an L / D 30: 1 screw, and an Electro Flight 311 J / h (150 hp) electric drive system. ), A 3-layer Cloreren feed unit and a 762 mm (30 in.) Black Clawson hanging head, model 300 XLHL, externally tapered to 610 mm (24 in.), Using a head clearance of 0.51 mm (20 mils) ) and an air exhaust gap of 152 mm (6 inches). The set extrusion temperatures, rotation speed, linear speed and coating thickness are given in table 4.

Samples of polypropylene unfinished products (920 cm '/ m (26 ounces / sq. Yards), piercing, direct knit weaving, unfinished products supplied by Shaw Industries under the Volunteer brand) were used. Test ethylene polymers were extruded onto the back of unfinished products, which were continuously passed through the extrusion coating faster than layered as individual canvases of unfinished products. Electric and gas infrared heaters were installed before the coating station for preheating unfinished products. The vacuum pressure roll separated by baffles with a 45 ^o vacuum section was installed and connected to a vacuum changing pump. The vacuum section is located at the contact point of the extrudate and unfinished products. The pressure of the crimp roll is set at 551.6 kPa (80 psi), and the cooling roll is regulated at 49 ^o C (120 ^o F). Secondary backing material (99 cm ³ / m ² (2.8 oz / sq. Yd.) Action Bac ^® woven polypropylene canvas supplied by Amoco Chemical Company, separation of fabrics and fibers) is applied to the back of the carpet samples after the extrudate is placed in the head and before crimping rolls with the formation of a laminate structure.

 After the coated samples were incubated for 24 hours at room temperature and 70% relative humidity, pile weave strength, wear resistance, and delamination resistance were determined.

 These examples show that homogeneously branched ethylene polymers produce carpet samples with good elasticity and good cohesion of carpet components, and that pile weave strength and wear resistance depend on processing conditions. These examples also show that improving the performance of the carpet base is achieved by using the stage of pre-heating the carpet, the optimized coating thickness, and / or the stage of vacuum pressing on the crimp roll.

 Resin LDPE extrusion coating (high pressure) gives a hard carpet with poor cohesiveness.

Table 5 summarizes the data on polymers, extrusion conditions and the results of determining the characteristics of the carpet for examples 55 ÷ 77. In these examples, the same extrusion equipment and extrusion conditions are used as indicated for examples 23 ÷ 54, except that instead of polypropylene unfinished products, polyamide unfinished products (920 cm ³ / m ² (26 ounces / sq. Yard), pierced , direct knitwear, unfinished products sold by Shaw Industries under the trademark Vocation ^tm ).

 Examples 55 to 77 of the invention also show that homogeneously branched ethylene polymers produce carpet samples with good elasticity and good cohesion of carpet components, and that pile strength and wear resistance depend on processing conditions. Like examples 23–53, these examples also show that improvements in carpet base performance are achieved using the preheating stage, the optimum coating thickness and / or the vacuum pressing step on the clip.

Table 6 summarizes the data on polymers, extrusion conditions and the results of determining the characteristics of carpets for examples 78 ÷ 86. In these examples, the same extrusion equipment is used as indicated for examples 1 ÷ 12, except that instead of direct weave products, polypropylene unfinished products of cross-weaving (707 cm ³ / m ² (20 ounces / square), pierced, knitwear sold by Shaw Industries under the brand name "Proton").

 Examples 78–83 of the invention show that homogeneously branched ethylene polymers produce cross-woven carpets with good elasticity and good cohesion of carpet components. The LLDPE resin of the extrusion coating used for comparative runs 84 ÷ 86 gives samples of a hard cross-woven carpet.

Table 7 summarizes the data on polymers, extrusion conditions and the results of characterization for examples 87 ÷ 90 of the invention. In these examples, the same extrusion equipment and extrusion conditions are used as indicated for examples 23 ÷ 54, with the exception that polypropylene unfinished products, namely 2750 denier polypropylene yarn, sewn at 566 cm ³ / m ² (16 ounces / sq. yard) with a direct knitwear supplied by Shaw Industries under the name "Quadratic", used instead of polypropylene unfinished products. In addition, in the case of Examples 88 to 90, the unfinished products were coated with an olefin suspension or emulsion, known as a primer, before extrusion coating.

 In particular, an aqueous dispersion of polyethylene particles was obtained by weighing 200 parts of water. Then, 0.4 parts of a Ciba-Geigy surfactant under the brand name "Igepal CO-430" was dispersed in water using a high speed homogenizer at a low speed. Then, 100 parts of a Quantum Chemical FN500 was added to the mixture using a high mixing speed agent for about 5 minutes. After starting stirring the FN500, 0.4 parts of Lenmar defoamer under the brand name "Marfoam" was added to reduce foaming of the mixture. Finally, 2.4 parts of a thickener sold by Sun Chemical International under the name "Printgum 600M" was added to the mixture. After adding this thickener, a minimum of 10 minutes of mixing is required.

This dispersion was applied to the back of the primary substrate in the traditional way. In particular, 1344 cm ³ / m ² (38 ounces / sq. Yards) with respect to the wet dispersion was applied to the lint-free side of the primary substrate with a roll over roll applicator at a speed of 3.05 m / min (10 ft / min).

After applying the dispersion, the carpet was sent to a traditional high-speed drying oven. The total residence time in the furnace was 5 minutes and the carpet reached a final temperature of about 143 ^{° C.} (290 ^° F.).

The observations made after applying the primer, but before applying the extruded adhesive backing material, showed that the carpet thus obtained had good beam impregnation and curl. Measurements showed that 141.5 and 283 cm ³ / m ² (4 and 8 ounces / square yards) of FN500 were applied to the carpet basis with respect to dry weight.

 Before applying the extruded adhesive backing, the carpet of Examples 88 ÷ 90 was also tested in accordance with ASTM D-1335 Test Method with Pile Weave Strength Measurement (see 1991 Annual Book of ASTM Standards, Vol. 07.01). This test measures the force required to tear one or both branches of a loop in a knit weave from the base. The carpet obtained in Examples 88–90 showed an average pile strength of 4.1 kg (9.0 pounds) before applying the extruded adhesive backing.

Example 87 includes an Adcote ^™ 50T4990 primer (ethylene acrylic acid copolymer dispersion available from Morton International, Woodstock, Illinois) applied at 141.5 cm ³ / m ² (4 oz / sq. Yard). For these examples, no vacuum was applied.

 Examples 87 to 90 of the invention show that homogeneously branched ethylene polymers produce carpet samples with good elasticity and good cohesion of carpet components, and that carpet performance can be improved by using a primer.

Table 8 summarizes the data on polymers, extrusion conditions and test results for examples 91 ÷ 96. In these examples, the same extrusion equipment and extrusion conditions are used as indicated for examples 23 ÷ 54, except that instead of direct weaving products polyamide unfinished products were used, namely 3050 denier polyamide 6, sewn at 707 cm ³ / m ² (20 ounces / square yards) in direct weaving, supplied by Shaw Industries under the brand name Vanguard ^tm , and unfinished products were coated with an olefin suspension or emulsion (i.e., primer) prior to the extrusion coating step. For these examples, no vacuum was applied. Test primers include Adcote ^tm 50T4990, a dispersion of an ethylene acrylic acid copolymer sold by Morton International (Woodstock, Illinois), and a suspension of LDPE, in which for the latter, unfinished products with a primer were supplied from Shaw Industries under the brand name Vanguard ^tm . These primers were applied with a mass of 141.5 cm ³ / m ² (4 ounces / sq. Yards) and 283 cm ³ / m ² (8 ounces / sq. Yards).

 These examples show that homogeneously branched ethylene polymers produce carpet samples with good elasticity and good cohesion of carpet components, and that carpet performance can be improved by using an aqueous primer.

 In these examples, the same extrusion equipment, extrusion conditions, and unfinished products are used as indicated for Examples 1 to 12, except that the double-slit or double-slit coating technology is evaluated with two application stations.

 In this test, unfinished products were first extrusion coated with a layer following the back of the carpet. This layer has been identified as the bottom layer. The once coated samples were then extrusion coated again with another layer identified as the top layer.

 Examples 97 to 109 of the invention show that 2-post extrusion of homogeneously branched ethylene polymers gives carpet samples with good elasticity and good cohesion of carpet components. The top layer may also contain carpet components. The top layer may also contain fillers or secondary polymeric materials to modify properties or reduce cost.

 Table 10 summarizes the data on polymers, extrusion conditions and the results of determining the characteristics of carpets for examples 110-117. In these examples, the same extrusion equipment, unfinished products, and extrusion conditions are used as indicated for Examples 1-12, except that single-head coextrusion technology is used. The various ethylene polymers tested are introduced into both extruders, respectively. Ethylene polymers are then fed simultaneously into one head and coextruded onto the back of unfinished products. A layer extruded onto the back of the carpet (i.e., adjacent to the primary backing material) is identified as the bottom layer, while the outer layer is identified as the top layer. Different thicknesses were tested, and different melt temperatures were used.

 Examples 110-117 of the invention show that coextrusion with one head of homogeneously branched ethylene polymers gives carpet samples with good elasticity containing fillers or secondary polymeric material to modify properties or provide cost savings.

 As a simulation of extrusion coating, a method has been developed for compression molding molten plates from test resins on the back of unfinished products. This method uses a programmable press. The following describes the technique.

Ethylene polymer tablets, granules, or powder are pressed into plates of about 16 grams and 0.64 mm (0.025 in) thick. The press used is the Tetrahedron programmable pneumatic press. Polymer tablets, granules, or powder are placed between the Mylar polyester films in the desired wafer mold and preheated for 30 s at 190 ^° C (374 ^° F) (this is achieved by introducing the samples into a preheated press and closing the plates sufficient to heat the sample polymer without compression). After 30 s, the plates are closed completely, and the Tetrahedron program is launched. The program provides a compression force of 2 tons (1814 kg) during cooling for 5 minutes at 38 ^o C (100 ^o F). As soon as the program ends, the sample is removed and further cooled. Samples are then stored for use later in the compression lamination step with the squares of the unfinished product.

Unfinished products were cut into squares (slightly larger than the size used to form the ethylene polymer samples, as described above) and stuffed onto an insulating board. The square samples were then preheated for 15 minutes in a Hot Pack oven at 110 ^° C.

The ethylene polymer plates obtained as described above were placed on a Mylar polyester film and placed in a preheated press at 190 ^° C (374 ^° F) for 5 minutes. The press plates were closed enough to preheat the plates without compressing them. The squares of the unfinished product that were preheated for about 5 minutes at a temperature of about 190 ^° C (374 ^° F) were then removed from the Hot Pack oven and installed in the press (i.e. returned to the preheated plastic plates). At this moment, the polymer plates and squares of the unfinished product were docked, a force of 0.1 tons (90.7 kg) was applied, and then the press was immediately open. Laminated samples were removed from the press and allowed to cool at room temperature. The time period required for compression lamination of the squares of the unfinished product and polymer plates was about 3-7 s.

 Table 12 shows the molding conditions and the results of characterization of various homogeneously branched essentially linear ethylene polymers.

 To determine the adhesion of the tested ethylene polymers to the squares of the unfinished product, the compression lamination method described for Examples 118-122 is used. Peel strength was determined using an Instron unit at a speed of 25 mm / min movable grip.

 Table 13 shows the results of determination of adhesion for various homogeneously branched polymers of ethylene, high-pressure LDPE, heterogeneously branched LLDPE and HDPE, laminated with squares made of polypropylene carpet unfinished products.

 These examples show that homogeneously branched substantially linear ethylene polymers and homogeneously branched linear ethylene polymers provide better adhesion than conventional polyolefin resins and, as such, provide improved performance when used as adhesive materials.

 The cross-sectional boundary of the carpet sample was recorded in microphotographs using a scanning electron microscope to detect adhesive interaction between various carpet components. Figure 3 presents a micrograph of a cross section of the interface for example 18 at 20 - and 50-fold magnification. Figure 4 presents a micrograph of a cross section of the interface for example 22 at 20 - and 50-fold magnification. It was found that while Example 18 has only satisfactory carpet performance, Example 22 has relatively good carpet performance. The improved characteristics of Example 22 are due to improved direct contact between the adhesive backing material and the primary backing material and significant encapsulation of the fiber bundles due to the improved impregnation of the bundles. The improved impregnation of the beams of example 22 compared with example 18 is clearly visible when comparing figure 3 and figure 4.

 To quantify the impregnation of the beams, a digital analysis was performed using a Quantimet 570 analyzer from Leica, Inc. (Deerfield, Ill.) And Version 2.0 QUIC Software. Digital images were obtained from a scanning electron microscope using a Sanyo VDC 3860 CCD video camera equipped with 12.5-75 mm Javelin zoom lenses.

 The total cross-sectional area of the fiber bundle was determined by tracking in a digital image using the binary characteristics of the QUIC program. The empty cross-sectional area (i.e., the area of the non-impregnated base material) of the beam is determined in the same way as the total cross-sectional area. The impregnation of the beam is then calculated as 1 minus the ratio of voids to the area of the beam.

 In FIG. 5 shows the relationship between the impregnation of the beam and the strength of the pile weave for polyamide and polypropylene carpets. For good carpet performance, an extrusion coating of a beam of ethylene polymer of more than 40%, preferably more than or equal to 60%, more preferably more than or equal to 80%, and most preferably more than or equal to 90%, is required.

 In addition, FIG. 5 shows that for a polyamide carpet, lower levels of impregnation of the fiber bundle are required to achieve the same level of wear resistance as for a propylene carpet. Here, the polyamide carpet has two important differences with respect to the polypropylene carpet. First, the polyamide carpet was washed with a weak aqueous solution of detergent as part of the dyeing operation. Secondly, the fibers of the polyamide carpet are polar, while the fibers of the polypropylene carpet are non-polar. However, the result of the requirement for a lower impregnation of the fiber bundle for a polyamide carpet shown in FIG. 5 is unexpected and surprising in that although a non-polar adhesive backing material is used, it turns out that high wear resistance is easier with a washed or cleaned polar carpet (i.e. polyamide) compared to a non-polar carpet (i.e. polypropylene). Typically, one of ordinary skill in the art expects these materials to be more attractive to each other and therefore require less permeability of the adhesive backing material into fiber bundles for a given level of wear resistance. This result is surprising in that the homogeneously branched ethylene polymers described in US Pat. No. 5,395,471 show improved adhesion to polypropylene substrates, even here even better results are obtained for polyamide fibers compared to polypropylene fibers. These results show that the choice of adhesive backing material for mechanical bonding and the step of cleaning or flushing the process can compensate for the absence or reduced chemical interaction between the various carpet components.

 To determine the relative ability of the tested ethylene polymers to impregnate carpet yarn (or fiber bundles) at acceptable processing temperatures and therefore to ensure good carpet performance, a solidification temperature is determined. In this test, the ethylene polymers tested are tested in the temperature range with a 800E rheometric mechanical spectrometer (S / N 035-014) assembled with a conical / cylindrical cage. Cartridge dimensions: 52 mm (inner diameter of the cup) x 50 mm (outer diameter of the load) x 17 mm (height of the load) x 0.04 (cone angle).

The gap between the plumb weight and the cup is calibrated to 50 μm ± 2 μm at room temperature, and the zero gap at 220 ^o C. The samples are loaded into the cup and heated until melted. The clearance is set at 50 μm ± 2 μm as soon as the load is pushed. Any excess samples or overflows are scraped off. The solidification measurement begins when the temperature of the instrument reaches 220 ^o C. the Cup is subjected to vibration at 1 Hz and 20% dynamic deformation. The experiment is carried out with a first slow cooling rate from 220 ^o C to 110 ^o C in increments of 10 ^o C. Samples are processed with a second slow cooling rate in steps of 5 ^o C from 110 ^o C to 40 ^o C. To prevent any compression of the cage, auto tension to maintain normal force slightly above zero. Auto stretching is set as follows: 5 g (preliminary stretching), 1 g sensitivity and 100 dyne / cm ² (1.02 kg / m ² ) lower limit. When the samples solidify, high torque is suddenly created. Auto tension is applied to prevent overloading the transducer before the specimen is fully cured. Auto tension is set as follows: 100% maximum applied deformation, 100 g • cm maximum allowable torque, 10 g • cm minimum allowable torque and 50% deformation control. The entire experiment is carried out in an atmosphere of dry nitrogen to minimize sample degradation.

 Table 14 shows the solidification temperatures of homogeneously branched ethylene polymers and high pressure LDPE resin extrusion coatings.

These examples show that homogeneously branched ethylene polymers have relatively low solidification temperatures and, as such, a better ability to saturate carpet yarn (or a bundle of fibers) compared to conventional low density polyethylene. It is believed that polyolefins suitable for use in the present invention have solidification temperatures below 100 ^° C, preferably less than or equal to 90 ^° C, more preferably less than or equal to 85 ^° C, and most preferably less than or equal to 80 ^° C. in some embodiments, the solidification temperature of the olefin extrusion coating resin, wherein homogeneously branched ethylene polymers are preferred, is in the range of from about 65 to about 100 ^o C, preferably - from about 70 to n imerno 90 ^o C, and more preferably - from about 70 to about 85 ^o C.

 In another test, wet vacuum cleaning and rinsing technology was investigated to determine its effect on the characteristics of the adhesive materials of the base of the present invention.

The test consisted of two different wet evacuation processes. The first wet evacuation process (indicated by Vac. 1 in the table below) consisted of cleaning the back of an unfinished product (i.e., the side of the primary backing material opposite the fibrous front side) using an industrial wet vacuum carpet cleaning unit equipped with a distribution / filling system carpet cleaning Rinsenvac ^tM supplied by Blue Lustre Products, Inc., (Indianapolis, iN) filled with tap water distributed at ambient temperature as a cleaning races thief. When using the first wet evacuation process, samples of the unfinished product are exposed to two separate wet vacuum cleaning processes and are completely air-dried after each cleaning. The second wet evacuation process (indicated by Vac. 2 in the table below) consisted of cleaning the back of the unfinished product using the Rinsenvac ^tm carpet cleaning system with the distribution of a hot (90 ^o C) aqueous solution of the Rinsenvac ^tm industrial carpet cleaner as a mixture of cleaning solutions . The concentration of the cleaning solution for the second wet evacuation process was 10 parts tap water per 1 part Rinsenvac ^tm detergent. When using the second wet evacuation process, samples of the unfinished product are subjected to one wet vacuum cleaning followed by complete drying in air, rinsing with water at ambient temperature and then the final stage of complete drying in air. For each flushing process, 1.9 L (0.5 gallons) of cleaning solution is distributed to 4.2 m ² (5 square yards) of unfinished products.

 In this test, non-washed (control) samples and washed samples of a stitched unfinished product were extruded using a single-layer head design, although single-head coextrusion and double-slot coextrusion could also be used. Ancillary equipment included preheaters and heat ovens.

The extrusion coating equipment consisted of a Black Clawson two-extruder coextrusion line with a primary extruder with a diameter of 89 mm (3 ^1/2 inches) with L / D 30: 1 and a secondary extruder with a diameter of 64 mm (2 ^1/2 inches) with L / D 24 :1. For these examples, only a large extruder worked at various speeds. The 760 mm slotted head joins and tapers to 690 mm with a head clearance of 0.51 mm (20 mils) and an air / exhaust gap of 152 mm (6 inches). The pressure of the crimp roll was set at 0.2 MPa (30 psi), and the temperature of the cooling roll was different.

Unfinished products were pieces of Volunteer ^tm carpet supplied by Shaw Industries. Carpet Volunteer ^tm consists of polypropylene fibers at 920 cm ³ / m ² (26 ounces / sq. Yards) and is characterized as a stitched carpet with a direct knit weave. Both the control non-washed and washed samples of the unfinished product were layered on Kraft paper during extrusion coating using an adhesive backing material. Both control non-washed samples and washed samples were first preheated in a convection oven prior to extrusion application of an adhesive backing material.

In this test, a substantially linear ethylene polymer designated XU-59100.00 as supplied by The Dow Chemical Company was used as the base adhesive material. The material XU-59100.00 is characterized as having a melt index of 30 g / 10 min and a polymer density of 0.900 g / cm ² . The preheating temperature was set at 71 ^° C (160 ^° F), the melt temperature of the extrusion coating was set at 260 ^° C (500 ^° F), the temperature of the cooling roll was set at 27 ^° C (80 ^° F), and the linear application speed extrusion coating was installed at 26 m / min (65 ft / min).

 After the samples with extrusion coating were aged for at least 24 hours at room temperature, the pile weave strength, wear resistance, and delamination strength were determined. The pile strength test was conducted in accordance with ASTM D-1335-67. The results of determining the wear resistance were obtained using the Velcrow test method, in which a roll with a diameter of 51 mm (2 inches) and a mass of 0.91 kg (2 pounds), covered with a pile side of the Velcrow standard, is passed 10 times over the front side of the coated carpet samples. The edge on a worn carpet is then compared with a set of carpet standards and evaluated on a 10-point scale (10 means zero edge). Wear resistance was also quantified using the fiber loop test, which is described below. In the general case, if the Velcrow number was below 6, or the wear resistance of the carpet was relatively poor, the strength of the pile weave was not determined.

 Table 15 below summarizes the results of these tests.

 The results presented in table 15 show that with equal coating weights of the adhesive base material, using a wet evacuation process step before applying the adhesive base material can significantly improve carpet performance relative to non-washed samples. The improvement is so significant that significantly reduced coating weights of the adhesive backing material can be used while maintaining excellent pile weave strength and wear resistance.

In another test, samples of a stitched unfinished product were coated with an extrusion coating to evaluate the effect of calcium carbonate as a high-heat filler and traditional blowing agent (e.g. azodicarbonamide) when used as an explosive agent. Calcium carbonate and azodicarbonamide were dry mixed with a substantially linear ethylene polymer in accordance with the weight percent indicated in the table immediately below. The substantially linear ethylene polymer had a melt index of 30 g / 10 min and a density of 0.885 g / cm ³ and was supplied by The Dow Chemical Company under the brand name XU-59400.00. The azodicarbonamide blasting agent was Epicell 301, which was supplied as a 30 wt.% Concentrate in low density polyethylene by EPI Chemical Company. Calcium carbonate, which had a specific heat of about 2.3 J · cm / ^o C (about 0.548 cal • cm ³ / ^o C), was supplied as a 75 wt.% Concentrate in low density polyethylene by Heritage Bag Company.

In this test, Volunteer ^™ unfinished products supplied by Shaw Industries were used. Unfinished products were polypropylene fiber, 920 cm ³ / m ² (26 ounces / sq. Yards), small pieces of stitched direct knitted carpet weave that were cut and layered on Kraft paper for each sample so that the adhesive base material of each example was extruded onto the back of the carpet (i.e., the primary backing material of small pieces of carpet). For each sample, before application to the adhesive backing material, unfinished products were first preheated in a convection oven.

In this test, the design of the die head was monolayer, and the auxiliary equipment included preheaters and elevated temperature furnaces. Specifically, the extrusion coating equipment consisted of a Black Clawson two-extruder coextrusion line with a primary extruder with a diameter of 89 mm (3 ^1/2 inches) with L / D 30: 1 and a secondary extruder with a diameter of 64 mm (2 ^1/2 inches) with L / D 24: 1. However, in this test, only a large extruder operated at various speeds. A die with a 760 mm gap was attached to the extruder and tapered to 690 mm with a 0.51 mm (20 mil) head clearance and 152 mm (6 inches) air / exhaust gap. The pressure of the crimp roll was set at 0.2 MPa (30 psi), and the temperature of the cooling roll was different. The preheating temperature of the unfinished products was set at 71 ^° C (160 ^° F), the temperature of the extrudable melt was set at 288 ^° C (550 ^° F), and the linear velocity was 23 m / min (75 ft / min). The temperature of the cooling roll was set at 38 ^° C (100 ^° F) for a sample that did not contain an explosive agent, and was set at 21.1 ^° C (70 ^° F) for samples containing an explosive agent.

 After the samples with extrusion coating were aged for at least 24 hours, they were tested for pile weave strength, wear resistance, Velcrow test, fluff test, elasticity and resistance to delamination. The pile strength test was conducted in accordance with ASTM D-1335-67. Wear resistance and the Velcrow test were based on qualitative assessments in which a roll of 51 mm (2 in.) And 0.91 kg (2 lb) in weight, coated with the fibrous side of the Velcrow standard, was skipped 10 times on the front side of each extrusion sample coated to wear the sample. The frill on a worn carpet was then compared with a set of standards and rated on a 10-point scale (10 means zero fluff).

For the quantitative determination of wear resistance, a test for the loosening of fiber loops was used. In this test, the wear resistance value is taken as the "number of fiber loop loops". The test involves cutting worn fibers with a pair of 152.4 mm (6 inches) of spring-loaded Fiskars scissors and comparing the weight of the sample before and after removing worn fibers. More specifically, the test for the loosening of fiber loops is carried out by providing samples with an extrusion coating measuring 203 mm (8 inches) in the transverse direction x 254 mm (10 inches) in the machine direction; clamping the samples so that they remain flat during the double rolling process; double rolling samples in the machine direction 15 times at a constant speed and at an angle of about 45 ^o using the Velcrow roll described above in this test; using a sample knife measuring 51 mm x 51 mm (2 inches x 2 inches) attached to a press punch certified by the National Federation of Analytical Equipment (NFAO) to provide two test samples for each sample; weighing and fixing the weight for each sample up to 0.1 mg using calibrated AE200 scales, carefully removing all worn fibers using a pair of 152.4 mm (6 inches) spring-loaded scissors with a guarantee of preservation of any part of the fiber loop; re-weighing and fixing two test specimens; and taking the difference in weight before and after removal of the worn fiber as the number of loops of fiber loops (VFA). Note that the blurring numbers of the fiber loops are inversely related to the Velcrow numbers: i.e., while high Velcrow numbers are desirable as an indicator of improved wear resistance, low fluff numbers indicate improved wear resistance.

 Table 16 shows the mass percentage of the additive and the results of determining the characteristics of the carpets.

 All examples in this test showed good elasticity, and examples with a Welcrow number of at least 6 all showed good resistance to delamination. Examples in which an exploding agent was used all had closed cells and a compressed matrix of adhesive base material, i.e. the thickness of the adhesive base material layer was approximately the same with and without an explosive agent. The data in table 16 show that the use of an explosive agent and a filler with a high heat content, either separately or in combination, significantly improves both the strength of the pile weave and the wear resistance of the extruded carpet compared to the equivalent weight of the resin coating without these additives. Also, the data of table 16 unexpectedly show that the use of these additives provides improved performance with a reduced coating weight of the adhesive base material.

 In another test, an unmodified control sample of adhesive backing material and two samples of adhesive backing material modified by adding ethylene polymer grafted with maleic anhydride were extruded onto pierced unfinished products using a single-layer head design, although single-head coextrusion and double-gap coextrusion could also be used. Ancillary equipment included: pre-heaters and furnaces with elevated temperature.

The extrusion coating equipment consisted of a Black Clawson two-extruder coextrusion line with a primary extruder with a diameter of 89 mm (3 ^1/2 inches) with L / D 30: 1 and a secondary extruder with a diameter of 64 mm (2 ^1/2 inches) with L / D 24 :1. For these examples, only a large extruder worked at various speeds. A head with a 760 mm gap was attached and tapered to 690 mm with a head gap of 0.51 mm (20 mils) and an air / exhaust gap of 152 mm (6 inches). The pressure of the crimp roll was set at 207 kPa (30 psi), the temperature of the chill roll was set at 24-27 ^o C (75-80 ^o F), and the linear extrusion speed was 23 m / min (75 ft / min )

Before applying the adhesive backing material, the unfinished articles were preheated to about 99 ^° C (210 ^° F) in a convection oven, and the temperature of the extrudable melt was 313-321 ^° C (595-610 ^° F).

The unmodified control adhesive base material was a substantially linear ethylene polymer having a melt index of 30 g / 10 min and a density of 0.885 g / cm ³ as supplied by The Dow Chemical Company under the brand name XU-59400.00. To obtain two modified adhesive base materials, XU-59400.00 was mixed by dry mixing with 10 wt.% With two different ethylene polymers grafted with maleic anhydride, each containing 1.0 wt.% Maleic anhydride, to obtain a final concentration of maleic anhydride 0 , 1 wt. % for two mixtures. The grafted polymers themselves were prepared in accordance with the procedures described in US Pat. No. 4,762,890. One grafted polymer, designated MAN-1 in Table 17, used high density polyethylene as the host polyethylene. In another grafted polymer, designated MAN-2 in Table 17, a substantially linear polyethylene polymer is used as the host polyethylene.

Unfinished products were small pieces of Vocation ^TM 26 carpet, supplied by Shaw Industries. Carpet Vocation ^tm 26 consists of polyamide fibers at 907 cm ³ / m ² (26 ounces / sq. Yards) and is characterized as a piercing, direct knit weaving carpet. Samples of the unfinished product were layered on Kraft paper during the extrusion coating process with a control adhesive base material and two modified adhesive base materials. The secondary backing material was not applied to the back of the samples after applying the adhesive backing materials, although it can also be used.

 After the samples with extrusion coating were aged for at least 24 hours at room temperature, the strength of the pile weave, the wear resistance, and delamination were determined. The pile strength test was conducted in accordance with ASTM D-1335-67. The wear resistance results were obtained using the Velcrow test method described above, where a roll of 51 mm (2 in) and 0.91 kg (2 lb) in weight, coated with the fibrous side of the Velcrow test, was skipped 10 times on the front side of the coated carpet samples. The frill on a worn carpet was then compared with a set of carpet standards and rated on a 10-point scale (10 means zero fluff). Wear resistance was also quantified using the above-described test for the loosening of fiber loops. In general, if the Velcrow number was lower than 6, or the wear resistance of a carpet sample was rather poor, the strength of the pile weave was not determined.

 Table 17 summarizes the results of this test.

 The results in Table 17 show that the introduction of maleic anhydride grafted ethylene polymers using either high density polyethylene (HDPE) or a substantially linear ethylene polymer as the host polymer provides significant improvements in the comparable pile strength and wear resistance. One advantage of these improvements is that practitioners can now use reduced coating weights of the thermoplastic adhesive backing material in order to reduce cost while maintaining still desirable levels of high performance.

Example 176 is the same as example 88 above, except that there is no adhesive backing extruded onto the carpet. The carpet thus obtained has good beam impregnation and curl. By measurements, it was shown that approximately 424 cm ³ / m ² (12 ounces / sq. Yards) of FN500 (on a dry basis) was applied to the carpet base. The carpet was also tested in accordance with ASTM D1335 Test Method for carpet pile strength (see 1991 Annual Book of ASTM Standards, Vol. 07.01). This test determines the force required to break one or both branches of the loop in a warp knitted carpet that does not contain a warp. This carpet, obtained in Example 176, showed an average pile strength of 4.1 kg (9.0 pounds).

Example 177 is the same as example 176, with the following changes. Firstly, antifoam was not used in the dispersion. Secondly, 0.5 parts of Aerosil A-300 from Degussa was introduced into the dispersion. Thirdly, instead of FN500, HDPE from Dow Chemical Co. was used. Under the brand of HDPE DOW 12065. Fourth, instead of CO-430, a surfactant under the brand name DA-6 from Sun Chemical International was used, the carpet was dried in a Blue M convection oven with air circulation at 132 ^o C (270 ^o F ) within 30 minutes The application for HDPE was 304 cm ³ / m ² (8.6 oz / sq. Yard). Average pile strength was measured at 1.8 kg (4.0 lbs).

Example 178 was the same as Example 177, except that Aerosil A-300 was removed and instead of HDPE, Quantum FE-532 ethylene vinyl acetate (EVA) copolymer was used instead of HDPE. Application for EVA was 354 cm ³ / m ² (10 ounces / sq. Yard). The average pile weave strength of the finished carpet was measured at 3.7 kg (8.2 lbs).

Example 179 was the same as example 178, except that instead of EVA, polyethylene grade MRL-0414 from Quantum was used. The application for polyethylene was 106 cm ³ / m ² (3 ounces / sq. Yards), and the average pile strength was measured at 1.04 kg (2.3 lbs).

 Example 180 was the same as example 177, except that the application for the FN500 was 191 cm '/ m (5.4 ounces / square yards), and the pile strength was measured at 2.4 kg (5.2 lbs.) )

Example 181 was the same as example 180, except that instead of Igepal CO-430, a surfactant under the brand name OT-75 from Sun Chemical Int. The application for the FN500 was 371 cm ³ / m ² (10.5 oz / sq. Yards), and the average pile strength was 1.95 kg (4.3 lbs.).

 Examples 182-193 were implemented to show various secondary substrates applied to the carpet obtained in Example 176.

In Example 182, a portion of the carpet manufactured in Example 176 was prepared on a secondary basis by placing a coextruded ethylene vinyl acetate / polyethylene copolymer sheet from Quantum Chemical Co. under the brand NA202 UE635 on top of the non-pile side of the carpet. The pre-extruded sheet was 0.58 mm thick (23 mil). The carpet was then placed in a convection oven set at 149 ^° C (300 ^° F) for 30 minutes, so as to allow the sheet to melt and bond to the rear of the pre-coated carpet. The carpet was then allowed to cool to room temperature.

 Examples 183-185 were also implemented as example 182, with the exception that the sheet of Quantum NA202 UE635 was 0.89, 0.94 and 1.3 mm thick (35, 37 and 50 mils), respectively.

Example 186 was carried out by taking the carpet from Example 176 and applying a VAE latex filled with calcium carbonate to the back of the carpet. The carpet was then placed in a convection oven at 149 ^° C (300 ^° F) for 30 minutes to dry the VAE. The coating weight was approximately 884 cm ³ / m ² (25 ounces / sq. Yards) with respect to the dry weight.

 Example 187 was carried out in the same way as example 186, except that the latex was unfilled VAE latex. In particular, this latex was obtained from Reichold Chemical Co. under the brand name Elvace 97808.

Example 188 was carried out in the same manner as Example 186, except that styrene butadiene rubber (BSC) latex filled with calcium carbonate was used instead of VAE latex. Latex BSK was applied so that the coating weight was 884 cm ³ / m ² (25 ounces / sq. Yard).

Example 189 was carried out by taking the carpet from Example 176 and spraying EVA powder on the back of the carpet. In particular, EVA powder was DuPont Elvax 410 powder, which was deposited with a mass of 354 cm ³ / m ² (10 ounces / sq. Yards).

 Example 190 was carried out in the same manner as Example 189, except that the powder was a polyolefin wax sold by Hercules under the brand name Polywax 2000.

Example 191 was carried out by taking the carpet from Example 176 and applying the compounded hot melt adhesive to the back of the carpet. In particular, the hot melt consisted of filled EVA and Piccovar CB-20 from Hercules, Inc. and was applied to the carpet at 1061 cm '/ m (30 ounces / sq. yards) and at a temperature of about 149 ^o C (300 ^o F).

 Example 192 was carried out in the same way as example 191, except that with a carpet base, a polyurethane foam lining was laminated through a hot melt. In particular, a polyurethane foam lining sold by Shaw Industries under the Duratech 100 brand was laminated using hot melt.

Example 193 was carried out in accordance with a preferred embodiment of the aqueous primer aspect of the present invention. A sample of the carpet of Example 176 had a sheet of polymer extruded directly on the back side. The polymer used was a polyethylene elastomer, indicated by the letter "G" in table 1 above. The density of this particular polymer was about 0.90 g / cm ³ . The melt index was 75.

To pre-heat the substrate, a Marshden infrared heater using propane fuel was used. The heater was installed at temperatures between about 93 ^° C (200 ^° F) and about 110 ^° C (230 ^° F). Carpet temperature was measured at about 63 ^° C (145 ^° F) at a point before the extruded sheet was obtained. The polymer was extruded at a thickness of 0.18 mm (7 mil) using a conventional extrusion coating system used for paper coating. In particular, a conventional extruder for applying a polyethylene coating was used with temperatures of 177 ^° C (350 ^° F) for the first cylinder, 191 ^° C (375 ^° F) for the second cylinder and 204 ^° C (400 ^° F) for the remaining cylinders, manifold and extrusion heads. The head was a slot type, which extruded a curtain of hot polymer on the back of the carpet. The carpet is then placed around the cooling roll with the back to the cooling roll at a temperature of 49 ^o C (120 ^o F). Linear speed is set at 7 m / min (23 ft / min). The carpet is pressed with a cooling roll with a clamping pressure of 0.31 MPa (45 psi). Although it is omitted in this specific example, a fabric such as conventional polypropylene secondary backing fabric from Amoco company Fabrics and Fibers, as a mark of "Action Bac ^®", can be laminated through the extruded sheet just before or at this chill roll.

 Examples 194-197 were carried out with the manufacture of carpet tiles according to the present invention.

Example 194 was made in accordance with the most preferred method of manufacturing carpet tiles. An unfinished product of 1.8 m (6 ft) wide was provided in the roll. The unfinished product contained polypropylene yarn sewn into a non-woven primary base from Akzo under the Colback brand name (a mixture of polyamide and polyester polymers), like cut tiles with a weight of facial yarn of approximately 1,592 cm ³ / m ² (45 ounces / sq. Yards). This unfinished product was passed below the extruder at 5.2 m / min (17 ft / min).

The extruder contained a molten polymer mixture having the following composition, wt.%:
Essentially Linear Ethylene Polymer (XU-59400.00 from Dow) - 24
Maleic anhydride grafted polyethylene (XU-60769.07 from Dow) - 4
Calcium Carbonate Filler (Marble 9, Georgia) - 59
Tackifier (Hercatac 1148 from Hercules) - 12
Carbon black concentrate - 1
Total - 100
The head temperature was about 260 ^{° C.} (500 ^° F.). About 884 cm ³ / m ² (25 ounces / sq. Yard) was applied in the first run, after which a sheet of reinforcing fabric was superimposed on top of this first polymer sheet. The reinforcing fabric in this example was 124 cm ³ / m ² (3.5 ounces / sq. Yards) Turag sheet (non-woven polypropylene fabric, supplied by Reemay as “3351”). After passing over the cooling roll, the carpet is folded for subsequent passage along the line for applying the second layer.

In the second run through the same line, a second layer of the same extrudate was applied over the reinforcing sheet. The total application, excluding Turag, was 1740 cm ³ / m ² (49.2 ounces / sq. Yard).

 After cooling, the carpet was cut into 45.7 cm '(18 sq. Inches) of tile and tested for pile strength and dimensional Aachen stability. The results are shown below in table 18.

Example 195 was carried out in the same way as example 194, except that the polyamide knit yarn was used for the front yarn at 707 cm ³ / m ² (20 ounces / square yard) with a straight stitch with a total application weight of 1910 cm ³ / m ² (54 oz / sq. yards).

Example 196 was carried out in the same way as example 195, except that the polyamide knit yarn was sewn at 1061 cm ³ / m ² (30 ounces / sq. Yard) with a straight stitch and the total application weight was 1860 cm ³ / m ² (52.6 oz / sq. Yard).

Example 197 was carried out in the same manner as Example 196, except that the primary base used was a non-woven polyester fabric sold by Freudenberg as "Lutradur". The total application weight was 1850 cm ³ / m ² (52.3 ounces / sq. Yard).

 Examples 198-208 were carried out to produce carpet tiles with different application weights in a second run. In addition, two different reinforcing materials were tested.

Example 198 was carried out in the same way as example 194 above, except that the extrudate applied in the first run had the following composition, wt.%:
Essentially linear ethylene polymer (XU-59400.00 from Dow) - 69
Calcium Carbonate Filler (Marble 9, Georgia) - 30
Carbon black concentrate - 1
Total - 100
389 cm ³ / m ² (11 ounces / square yards) of this extrudate was applied to the back of an unfinished product, which consisted of polypropylene yarn sewn into a woven polypropylene primary backing at approximately 920 cm ³ / m ² (26 ounces / sq. yard) in a knitted pattern.

In Examples 198-203, Turag fabric with 124 cm ³ / m ² (3.5 oz / sq. Yard) was embedded between the first layer of extrudate and the second.

In examples 204-208, 49.5 cm ³ / m ² (1.4 ounces / square yards) of fiberglass canvas from ELK was used as the reinforcing layer. Corp.

In each of the examples 198-208, the second layer of extrudate, which was applied in the second run in a line, had the following composition, wt.%:
Essentially linear ethylene polymer (XU-59400.00 from Dow) - 24
Maleic anhydride grafted polyethylene (XU-60769.07 from Dow) - 4
Calcium Carbonate Filler (Marble 9, Georgia) - 59
Tackifier (Hercatac 114876 from Hercules) - 12
Carbon black concentrate - 1
Total - 100
The coating weight for the second run varied as shown in Table 19 below. The carpet was cut into tiles and subjected to an Aachen dimensional stability test with the results below.

 Although particularly preferred and alternative options are described herein, it should be noted that other options and modifications may be made without departing from the scope of the invention described herein. The attached claims determine the scope of this patent.

Claims (14)

 1. A carpet comprising a primary backing material having a front and back sides, a plurality of fibers attached to the primary backing material, extending from the front side of the primary backing material and remaining free on the back side of the primary backing material, adhesive backing material and optional secondary backing material, adjacent to the adhesive base material, in which at least one of the primary base material, adhesive base material or optional secondary base material consists of, in m at least one homogeneously branched ethylene polymer having a short chain branching distribution index (SCRC) of greater than or equal to 70%.  2. The carpet according to claim 1, in which the adhesive base material consists of at least one homogeneously branched ethylene polymer. 3. The carpet according to claim 1, wherein the homogeneously branched ethylene polymer contains ethylene and at least one alpha-C _3-20 α-olefin. 4. The carpet according to claim 3, in which the homogeneously branched ethylene polymer is a copolymer of ethylene and a single C _3-20 alpha-olefin. 5. The carpet according to claim 4, in which one alpha-C _3-20 -olefin is selected from the group consisting of propylene, 1-butene, 1-isobutylene, 1-pentene, 1-hexene, 4-methyl-1-pentene , 1-heptene and 1-octene. 6. The carpet according to claim 5, in which one alpha - C _3-20 -olefin is 1-octene. 7. The carpet according to claim 1, in which at least one homogeneously branched ethylene polymer is further characterized as having a single melting peak determined by differential scanning calorimetry (DSC), between -30 and 150 ^o C. 8. The carpet according to claim 7, in which at least one homogeneously branched ethylene polymer is a substantially linear ethylene polymer having: (a) a melt flow ratio of I ₁₀ / I ₂ ≥5.63; (b) a molecular weight distribution of M _w / M _n as determined by gel permeation chromatography and the equation
(M _w / M _n ) ≤ (I ₁₀ / I ₂ ) - 4.63,
and (c) the critical shear stress at the beginning of bulk melt fracture is greater than 4 • 10 ⁶ dyne / cm ² .  9. The carpet according to claim 1, in which at least one homogeneously branched ethylene polymer is a homogeneously branched linear ethylene polymer.  10. A method of producing a carpet containing a primary base material having a front and a back side, a plurality of fibers attached to the primary base material, extending from the front side of the primary base material and remaining free on the back side of the primary base material, adhesive base material located on the back side of the primary backing material, and an optional secondary backing material adjacent to the adhesive backing material, comprising the step of extruding an adhesive mat main base or optional secondary base material on the back surface of the primary base material, where the extruded adhesive base material or optional secondary base material consists of at least one homogeneously branched ethylene polymer having a short chain branching distribution index (SCRC) of greater than or equal to 70 %  11. The method of claim 10, wherein the adhesive base material is extruded onto the back of the primary base material. 12. The method according to claim 10, in which at least one homogeneously branched ethylene polymer is further characterized as having a single melting peak, determined by differential scanning calorimetry (DSC), between -30 and 150 ^o C. 13. The method of claim 12, wherein the at least one homogeneously branched ethylene polymer is a substantially linear ethylene polymer having: (a) a melt flow ratio of I ₁₀ / I ₂ ≥5.63; (b) a molecular weight distribution of M _w / M _n as determined by gel permeation chromatography and the equation
(M _w / M _n ) ≤ (I ₁₀ / I ₂ ) - 4.63,
and (c) the critical shear stress at the beginning of bulk melt fracture is greater than 4 • 10 ⁶ dyne / cm ² .  14. The method of claim 10, wherein the at least one homogeneously branched ethylene polymer is a homogeneously branched linear ethylene polymer.

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