Spunbond nonwoven fabric and its manufacturing method

Abstract

According to the present invention, there is provided a spunbond nonwoven fabric that has excellent mechanical properties and can function as a latex material even though it does not contain latex or PVC layers that generate harmful substances, and can provide an environmentally friendly carpet with excellent pull-out strength, and a method for producing the same.

Description

[Technical field]

[0001] [Cross-reference to related applications] This application claims the benefit of priority to Korean Patent Application No. 10-2020-0187594, filed December 30, 2020, and Korean Patent Application No. 10-2021-0189932, filed December 28, 2021, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a spunbond nonwoven fabric for carpets suitable for use as a material for automotive flooring, and a method for producing the same. [Background technology]

[0003] Carpets are interior floor products in homes, public institutions, hotels, restaurants, automobiles, etc., and are used for the purposes of decoration, comfort, sound absorption, and ease of walking (cushioning).

[0004] Existing carpet structures consist of carpet yarn (BCF yarn (pile)), base fabric (nonwoven fabric), latex and PVC (rubber, EVA, etc.).

[0005] Among these, the latex and PVC materials generate harmful fumes during the coating process on the base fabric (non-woven fabric) made from tufted carpet yarn. In the finished product, which belongs to the interior product group for car floors, they generate volatile harmful substances that pollute the quality of the air inside the car.

[0006] That is, in the construction of the carpet, the latex coating process and the PVC layer are the layers that release the most volatile harmful substances.Furthermore, among the post-processing steps in manufacturing the carpet, there is a problem that a large amount of harmful substances are released during the process of coating and curing the PVC layer.

[0007] As a result, air quality regulations are becoming increasingly stringent worldwide and product development is moving towards eliminating latex and PVC materials.

[0008] However, the reality is that a product that meets air quality regulations while also having excellent functionality, such as strong pull-out properties for nonwoven fabrics, has yet to be developed. Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention aims to provide a spunbond nonwoven fabric for carpets, which can stably fix carpet yarn to the nonwoven fabric without using latex or PVC materials and uses a nonwoven fabric that serves as a highly functional latex layer, and a method for producing the same.

[0010] In addition, this specification provides a spunbond nonwoven fabric for carpets that is environmentally friendly because it does not contain latex or PVC materials and does not generate volatile harmful substances (fumes), and a manufacturing method thereof. [Means for solving the problem]

[0011] As used herein, in accordance with one embodiment, The fiber web comprises a composite filament having a form of a split yarn, the composite filament including 60 to 80% by weight of a polyester filament having a melting point of 250° C. or more and 20 to 40% by weight of a copolymer filament having a melting point of 170° C. or less; The division rate according to the following formula 1 is 50% or more, The present invention provides a spunbond nonwoven fabric having room temperature strength of 18 kgf / 5 cm or more, hot strength of 4.0 kgf / 3 cm or less, and hot elongation of 80% or more, according to the standard test method of KS K 0521.

[0012] [Formula 1] Split rate (%) = (number of split filaments) / (number of split filaments + number of unsplit filaments) x 100

[0013] (In formula 1, The number of split filaments and the number of unsplit filaments are the numbers of split and unsplit filaments observed in a photograph of the cross section of the nonwoven fabric taken with a microscope (SEM) at a magnification of 200 times (×200), and the split rate is the average value of 10 photographs.

[0014] Also, according to another embodiment, the present specification provides A step of spinning and drawing 60-80% by weight of polyester filaments having a melting point of 250°C or more and 20-40% by weight of copolymer filaments having a melting point of 170°C or less and a melt index (MI) of 15-25g / 10min (ASTM 1238, 190°C) through a multi-segment composite spinneret to prepare composite filaments having a form of split yarn; laying up the composite filaments to form a fibrous web; bonding said fibrous webs by thermal bonding; and splitting filaments in the thermally bonded web; The method for producing the spunbonded nonwoven fabric has a split ratio of 50% or more according to the following formula 1 after the step of splitting the filaments in the thermally bonded web:

[0015] [Formula 1] Split rate (%) = (number of split filaments) / (number of split filaments + number of unsplit filaments) x 100

[0016] (In formula 1, The number of split filaments and the number of unsplit filaments are the numbers of split and unsplit filaments observed in a photograph of the cross section of the nonwoven fabric taken with a microscope (SEM) at a magnification of 200 times (×200), and the split rate is the average value of 10 photographs.

[0017] Also provided herein, according to another embodiment, is a carpet comprising the spunbond nonwoven fabric.

[0018] A carpet and a method for producing the same according to an embodiment of the invention will now be described in detail.

[0019] Prior to this, unless expressly stated otherwise in this specification, the terminology used is for the purpose of referring to particular embodiments only and is not intended to limit the invention.

[0020] As used herein, the singular forms "a," "an," and "the" include the plural forms as well, unless the context clearly indicates to the contrary.

[0021] As used herein, the meaning of "comprising" is to embody certain features, regions, constants, steps, operations, elements, components and / or ingredients, and does not exclude the presence or addition of other particular features, regions, constants, steps, operations, elements, components and / or groups.

[0022] In this specification, terms including ordinal numbers, such as "first" and "second," are used for the purpose of distinguishing one component from another component, and are not limited by the ordinal number. For example, within the scope of the present invention, a first component may be named a second component, and similarly, a second component may be named a first component.

[0023] The present invention will be described in detail below.

[0024] According to one embodiment of the invention, it is possible to provide a spunbond nonwoven fabric which includes a fiber web formed from composite filaments having a form of split yarn, the composite filaments including 60 to 80% by weight of polyester filaments having a melting point of 250°C or higher and 20 to 40% by weight of copolymer filaments having a melting point of 170°C or lower, and which has a room temperature strength of 18 kgf / 5 cm or more, a hot strength of 4.0 kgf / 3 cm or less, and a hot elongation of 80% or more, as measured by the standard test method of KS K 0521.

[0025] As a result of extensive research, the inventors have confirmed that when a composite fiber consisting of split yarns of matrix and binder materials having specific content ratios and melting points different from each other is used, a carpet using a nonwoven fabric that can exhibit the functions of latex and PVC layers can be continuously manufactured without performing a coating process of latex and PVC materials.

[0026] Therefore, the present specification is characterized in that a nonwoven fabric having the functionality of a latex material is manufactured from the existing carpet structure to provide a carpet without a latex layer.

[0027] In particular, in existing carpet layers, latex material plays a role in fixing carpet yarn (BCF yarn). However, since the latex material causes environmental problems, this specification aims to manufacture a nonwoven fabric for carpets that also plays the role of a latex layer by improving the function (pulling strength) of the nonwoven fabric with the carpet yarn without using a separate latex material.

[0028] Therefore, by eliminating the latex coating process during the manufacturing of the carpet, it is possible to eliminate the generation of harmful fumes and reduce VOCs (volatile organic compounds) in the finished product, making it environmentally friendly when used as an interior material for car floors.

[0029] The nonwoven fabric according to the present specification is characterized in that it is a spunbond nonwoven fabric comprising a fiber web formed from composite filaments having the form of split yarns, the composite filaments including 60 to 80% by weight of polyester filaments having a melting point of 250°C or higher and 20 to 40% by weight of copolymer filaments having a melting point of 170°C or lower.

[0030] Specifically, the nonwoven fabric can be formed in the form of split yarns by using polyester filaments having a melting point of 250°C or higher as a matrix material and copolymer filaments having a melting point of 170°C or lower as a binder material.

[0031] In this specification, the split yarn has a multi-split cross-sectional shape, which means that the two polymers are ultra-thinned by using a composite spinneret having a multi-split form in the method for producing ultrafine fibers, and the cross section inside the single yarn includes a multi-split shape, so the cross section is not limited to a circular shape. For example, the multi-split cross-sectional shape may include 8 to 64 split yarns, 16 to 32 split yarns, or 32 split yarns inside the single yarn.

[0032] Therefore, the nonwoven fabric can be given the functionality of a latex layer without a latex material by specifying the mixture ratio of the matrix and binder material and using a composite filament containing 8 to 64 divided yarns.

[0033] In particular, the binder material melts during post-processing (tufting, heat treatment, backing and molding) of carpet manufacturing and acts as an adhesive and provides high elongation for molding performance, so it can play the role of a latex layer.

[0034] That is, the polymer used as the binder material acts as an adhesive between the carpet raw yarn (BCF yarn) and the base fabric (nonwoven fabric) by melting when the back side of the tufting is heat-treated after the tufting process. Also, in the final molding process for manufacturing the carpet for automobiles, the binder polymer becomes in a state just before melting in a high-temperature environment of 180 to 200°C, and plays a role in expressing high elongation and enabling molding.

[0035] Here, if the binder content is 19% by weight or less, the shape of the split yarn is difficult to form (the binder polymer is not extruded or is biased to one side due to uneven spinning pressure), and the binding force between the filaments constituting the nonwoven fabric is insufficient, making it prone to breakage during post-processing. If the shape of the split yarn is not uniform, deviations in physical properties occur depending on the position of the nonwoven fabric, which can cause tearing and low pull-out strength during the molding process of post-processing.

[0036] In addition, if the binder content is 41% by weight or more, there will be a shortage of matrix components that act as a support in the post-processing process for manufacturing a carpet at temperatures above 180°C, and as a result, there will be a lot of binder raw material that becomes molten at high temperatures, which will cause deformation (shrinkage, expansion) due to external forces, making post-processing impossible.

[0037] Furthermore, if the melting point of the binder raw material is 170°C or higher, it will not melt at the process temperature at which it must be able to provide strength to the nonwoven fabric, and act as an adhesive and achieve high elongation, and therefore will not be able to function as a binder filament.

[0038] The filament may include split yarns having an average diameter of 22 to 31 μm and a fineness of 5.0 to 9.0 denier before splitting. More specifically, the split yarns may have an average diameter of 22 to 31 μm and a fineness of 5.0 to 9.0 denier before splitting. The cross section of the composite filament before splitting may be circular or spherical, divided into 8 to 64 parts.

[0039] When the cross-sectional shape of the composite filament is a circular cross-section, not in the form of split yarn, a binder filament must be additionally spun to mix the matrix filament and the binder filament to form a web. In this case, when the filaments are mixed, there is a limit to the uniformity, and therefore there are parts where there is no binder filament. The binder filament is a factor that determines the tensile strength of the nonwoven fabric, and the tensile strength is determined depending on the presence / absence of the binder filament and the bonding state. However, in the case of a circular cross-sectional shape, there are parts where there is no binder filament, as described above, which reduces the strength and elongation, and may also reduce the pull-out strength.

[0040] Furthermore, the nonwoven fabric according to the present specification may have a split ratio according to the following formula 1 of 50% or more, 54% or more, or 56% or more.

[0041] [Formula 1] Split rate (%) = (number of split filaments) / (number of split filaments + number of unsplit filaments) x 100

[0042] (In formula 1, The number of split filaments and the number of unsplit filaments are the numbers of split and unsplit filaments observed in a photograph of the cross section of the nonwoven fabric taken with a microscope (SEM) at a magnification of ×200, and the split rate is the average value of 10 photographs.

[0043] The test piece of the cross section of the nonwoven fabric used in measuring the split ratio can be adjusted in various ways. For example, a test piece of the nonwoven fabric having a size of 3 mm×3 mm can be used.

[0044] If the division ratio is less than 50%, the adhesive area of ​​the binder polymer is low, and the binder is insufficient, which may result in a decrease in the mechanical properties and pull-out strength of the nonwoven fabric.

[0045] The polyester filaments used as the matrix material may contain one or more polyester polymers selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polynaphthalene terephthalate, and recycled raw materials thereof.

[0046] The polyester filaments may contain a polyester polymer having an intrinsic viscosity (IV) of 0.60 to 0.90 dl / g and a melting point of 250° C. or higher.

[0047] The binder material uses copolymer filaments having a melting point of 170° C. or less and a melt index (MI) of 15 to 25 g / 10 min (ASTM 1238, 190° C.).

[0048] Specifically, the copolymer filament may be one or more selected from the group consisting of polyolefins having a melting point of 170° C. or less and a melt index (MI) of 15 to 25 g / 10 min (ASTM 1238, 190° C.). The polyolefin may be polyethylene or polypropylene.

[0049] In this specification, MI (Melt index) refers to the value measured at 190°C according to ASTM 1238.

[0050] The nonwoven fabric provided by this method has excellent inter-filament adhesion, excellent fixation of carpet yarn, and can improve elongation compared to conventional methods. Furthermore, by using the nonwoven fabric as a carpet base fabric, the pull-out strength of the final product can be improved, and since no latex or PVC materials harmful to the human body are used, an environmentally friendly material can be provided.

[0051] According to one embodiment of the invention, the nonwoven fabric can simultaneously satisfy physical properties of room temperature strength of 18 kgf / 5 cm or more, hot strength of 4.0 kgf / 3 cm or less, and hot elongation of 80% or more, as measured by the standard test method of KS K 0521. More specifically, the strength and elongation can be further optimized by configuring the nonwoven fabric so that the above-mentioned split ratio is 54% or more. Therefore, the nonwoven fabric can have room temperature strength of 19 kgf / 5 cm or more, hot strength of 3.0 kgf / 3 cm or less, and hot elongation of 81% or more, as measured by the standard test method of KS K 0521.

[0052] The nonwoven fabric has a weight per unit area of ​​90 g / m 2 When the apparent density is 225~310g / cm 3 The nonwoven fabric may be a spunbond nonwoven fabric.

[0053] In addition, the spunbond of the present invention can improve the pull-out strength of carpets. Therefore, the carpet of the present invention has a pull-out strength of 2.0 (kgf) or more according to the standard test method of KS K ISO 4919, and can be used as an automobile flooring material.

[0054] Meanwhile, according to another embodiment of the present invention, there is provided a method for producing a spunbonded nonwoven fabric, comprising the steps of: spinning 60-80% by weight of polyester filaments having a melting point of 250°C or higher and 20-40% by weight of copolymer filaments having a melting point of 170°C or lower and a MI (melt index) of 15-25g / 10min (ASTM 1238, 190°C) through a multi-split composite spinneret, and drawing the spinned composite filaments to produce a composite filament having a split yarn form; laminating the composite filaments to form a fiber web; bonding the fiber web by thermal bonding; and splitting the filaments in the thermally bonded web into multiple filaments.

[0055] The spunbond nonwoven fabric for carpet according to this specification comprises a fiber web in the form of split yarns, which are formed by conjugating polyester filaments as a matrix and copolymer filaments as a binder having a specific melting point and MI under certain conditions, and is produced by the spunbond method.

[0056] In the spunbonding method, the polyester and copolymer are melted independently, and the number of extrusion holes for the different resins can be adjusted. The polyester and copolymer are spun and drawn through a single composite spinneret that spins the fibers into a multi-segment cross-sectional shape to obtain a composite filament.

[0057] In addition, the method for producing the spunbonded nonwoven fabric can be carried out using a continuous extruder, so that a nonwoven fabric which has excellent mechanical properties and a splitting ratio and therefore improves the pull-out strength of a carpet can be efficiently and continuously produced.

[0058] Specifically, the polyester (matrix) and copolymer (binder) are prepared, then fed into a continuous extruder, heated and melted, and then spun through a multi-segment spinneret. Through this process, the filament can include split yarns with a multi-segment cross section in which the inside of a single yarn is split. The multi-segment spinneret can be used by adjusting the number of capillaries to have 8 to 64 split yarns or 16 to 32 split yarns.

[0059] In addition, during the composite melt spinning, the number of capillaries in the spinneret can be adjusted through the spinneret so that the ratio of matrix (polyester) and binder (copolymer) becomes 60-80% by weight:20-40% by weight.

[0060] Here, the specific details regarding the configuration of the polyester filaments as the matrix material and the copolymer filaments as the binder material are replaced with the details regarding the spunbond nonwoven fabric described above.

[0061] The spunbond can also be provided by using a continuous extruder.

[0062] The step of preparing the composite filament may further include a step of adjusting the fineness of the composite filament so that the composite filament has an average diameter of 22 to 31 μm and a fineness of 5.0 to 9.0 denier before the step of splitting the filament into multiple filaments in the thermally bonded web.

[0063] The composite filaments spun in the composite spinning form can be sufficiently stretched by controlling the spinning speed using a high-pressure air stretching device, and the discharge rate and the number of capillaries of the spinneret can be adjusted to a level of 5.0 to 9.0 denier.

[0064] For example, the drawing is performed under a spinning speed condition of 3,000 m / min to 5,000 m / min. More specifically, for more sufficient drawing, the spinning speed may be 4,500 m / min to 5,000 m / min. If the spinning speed is less than 3,000 m / min, there is a problem that the nonwoven fabric shrinks in the heat bonding stage due to insufficient drawing of the filaments, and there is a problem that adhesion occurs between the filaments in the drawing stage due to insufficient cooling caused by an influence on cooling efficiency, resulting in poor drawing and fiber opening. In addition, if the spinning speed is more than 5,000 m / min, there is a problem that the filaments are cut during drawing, making it impossible to form the surface shape of the nonwoven fabric.

[0065] The web forming and heat bonding steps can be accomplished by fiber opening techniques according to methods well known in the art.

[0066] In addition, the step of splitting the filaments in the heat-bonded web is performed using a water jet, i.e., after spinning composite fibers using split yarns having a multi-split cross section, the split yarns are formed into a web and then treated with a water jet, whereby the split yarn cross sections are split as they are.

[0067] Specifically, the filament fiber thus produced is placed on a conveyor in the form of a web, and then the apparent density of the web is adjusted to 225 to 310 g / cm. 3 can be adjusted to.

[0068] The fiber web with the adjusted apparent density is thermally bonded using a calendar roll or hot air, and then passed through a water jet to divide the filaments into a multi-division cross-sectional shape. At this time, a spunbond nonwoven fabric with a thickness of 0.31 mm to 0.40 mm can be manufactured by adjusting the water pressure of the water jet in stages.

[0069] For example, when a physical external force is applied by a high-pressure water jet to a nonwoven fabric that has undergone a thermal bonding process, the filaments are split while maintaining the shape of the split thread. That is, in this process, the two polymers that form the split thread eventually break the physical bond between the polymers due to their insufficient compatibility (affinity) with each other, and the filaments are split into the shape of ultrafine threads. The pressure of the high-pressure water jet is not particularly limited, but applying pressure in multiple steps at a level of 50 to 280 bar can split the split threads into ultrafine threads, making the web structure more complex and further improving the strength of the nonwoven fabric.

[0070] In addition, the high pressure water jet can be applied in two or more stages with different pressure ranges within the pressure range. According to one embodiment of the invention, the high pressure water jet can be applied in the order of a first stage pressure intensity of 50-80 bar, a second stage pressure intensity of 150-280 bar, and a third stage pressure intensity of 50-80 bar. By adjusting the water pressure in stages as described above, not only can the thickness of the nonwoven fabric be adjusted, but also the cross section of the split yarns split to a desired level can be maintained.

[0071] In this case, when pressure is applied by the high-pressure water jet, if pressure is applied only once instead of in multiple stages, there is a problem that stripe-shaped marks in the vertical direction are left and unevenness in weight, thickness and division rate occurs when a single stage of high-pressure water jet is applied. Also, the fewer the water jet processing stages, the more the water jet nozzle and water pollution level are affected.

[0072] Therefore, in the present invention, the nonwoven fabric is treated with a water jet in multiple stages, so that the nonwoven fabric is divided multiple times through stages, thereby increasing the division rate and imparting the function of uniformly rearranging the filaments as described above.

[0073] After the step of splitting the filaments in the thermally bonded web, the split rate according to the following formula 1 is 50% or more.

[0074] [Formula 1] Split rate (%) = (number of split filaments) / (number of split filaments + number of unsplit filaments) x 100

[0075] (In formula 1, The number of split filaments and the number of unsplit filaments are the numbers of split and unsplit filaments observed in a photograph of the cross section of the nonwoven fabric taken with a microscope (SEM) at a magnification of ×200, and the split rate is the average value of 10 photographs.

[0076] The spunbond nonwoven fabric formed by the above method from filaments having a split yarn form with a specified ratio of matrix to binder can be used as a base fabric in the manufacture of carpets.

[0077] Therefore, according to another embodiment of the invention, there is provided a carpet including the spunbond nonwoven fabric and a method for producing the same.

[0078] The carpet can be provided by a tufting process and a cutting process using carpet yarn and a spunbond nonwoven fabric.

[0079] In particular, the carpet manufacturing method does not require the conventional coating process of latex and PVC layers, and therefore not only can the process be shortened, but also no harmful substances are generated, providing an environmentally friendly product.

[0080] Therefore, the carpet has carpet yarn fixed to one side of the nonwoven fabric and does not include a latex layer.

[0081] The carpet is obtained by the steps of: fixing carpet yarn to a nonwoven fabric on one side of the spunbond nonwoven fabric by tufting and heat treatment processes; and cutting the nonwoven fabric fixed to the carpet yarn.

[0082] In addition, the method may further include a step of laminating a backing layer on the nonwoven fabric fixed to the carpet yarn between the step of fixing the carpet yarn and the cutting step.

[0083] Specifically, a step is carried out on one side of the spunbond nonwoven fabric provided by the above method, in which carpet yarn is tufted into the nonwoven fabric, and the nonwoven fabric is fixed to the carpet yarn by heat treatment.

[0084] In this case, the step of fixing the carpet yarn to the nonwoven fabric may include a step of heat treating the back surface of the tufted nonwoven fabric after the tufting process.

[0085] The tufting, heat treatment and cutting processes are carried out by using known methods and equipment, and the carpet yarn is fixed to one side of the nonwoven fabric using needles. At this time, the tufting is carried out in a loop shape under a predetermined gauge (e.g., 64 / 5 gauge) condition.

[0086] The carpet yarn used in the tufting process may include BCF yarn, which is well known in the art. The carpet yarn may have aesthetic and cushioning functions and may have a certain fineness (e.g., 500 to 3000 denier) and height (e.g., 3.0 to 7 mm). Through the tufting process, the carpet yarn is embedded in one side of the nonwoven fabric so that it is visible.

[0087] The lamination process of the backing layer is also performed by a method well known in the art. Specifically, a heavy weight web can be laminated onto the backing layer, and the heavy weight web can be a short fiber or long fiber nonwoven web.

[0088] By using a method including a lamination process of the backing layer, the carpet can be provided by including the steps of: implanting carpet yarn into a nonwoven fabric on one side of the spunbond nonwoven fabric by a tufting process; fixing the carpet yarn by heat treating the tufted nonwoven fabric; laminating a backing layer; and cutting the laminated carpet.

[0089] Thus, a carpet according to the present invention may be constructed without a latex layer, including a spunbond nonwoven, carpet yarn and a backing layer.

[0090] In a preferred example, the nonwoven fabric is tufted (a process of implanting yarn into the nonwoven fabric) with a loop type polypropylene BCF (Bulky Continuous Filament) yarn of about 3000 denier (De') / 150 filament (Fila.) on the surface at a gauge (a unit indicating the needle density in a tufting device, the needle interval is expressed in inches, and the gauge determines the density in the width direction of the TUFTED CARPET) of about 64 / 5 gauge and a stitch (a density in the length direction of the tufted carpet) of about 13 / 1. Next, the back side of the tufted product is heat-treated using a heat chamber at about 180°C, and a cutting process (size: 50cm x 50cm) is performed as the final process to provide a carpet. The carpet heat-treated by the above method may further include a process of laminating heavy long or short fibers as a backing layer before the cutting process.

[0091] The carpet provided in this way has high performance with a pull-out strength (strength to pull the loop after tufting of loop type) of about 2.0kgf according to the standard test method of KS K ISO 4919, so it can be applied in various fields, specifically, it can be used as an interior material for car flooring. Effect of the Invention

[0092] According to the present invention, a carpet that can be used as an interior product for car floors and a method for manufacturing the same is provided, which includes a spunbond nonwoven fabric as a base fabric, which has excellent mechanical properties and can act as a latex material, thereby eliminating the need for latex and PVC coating processes, thereby eliminating the generation of fumes, which are harmful substances, and reducing VOCs (volatile organic compounds) in the finished product. BEST MODE FOR CARRYING OUT THEINVENTION

[0093] The functions and effects of the present invention will be described in more detail below with reference to specific examples of the present invention. However, these examples are merely presented as examples of the present invention, and do not define the scope of the invention.

[0094] [Example 1] A matrix made of polyethylene terephthalate (PET) material with a melting point of 255°C and a binder made of polyethylene material (MI:20) with a melting point of 137°C were prepared, and then fed into a continuous extruder and melted by heating, and then composite spun through one spinneret to produce filaments with an orange cross section divided into 32 parts. At this time, the number of capillaries in the spinneret was adjusted so that the ratio of the matrix (polyester) and binder (copolymer) was 70wt%:30wt% using the composite spinneret.

[0095] Next, the 32-part composite filament spun through the spinneret was solidified with cooling air at 15°C, and then sufficiently drawn using a high-pressure air drawing device to a spinning speed of 5,000 m / min to produce a composite filament fiber having a fineness of 5.0 to 9.0 denier and an orange cross section shape.

[0096] Next, the composite filament fiber thus produced is laminated in a web shape on a continuously moving metal conveyor net by a conventional fiber spreading method, and then subjected to a calendering process using flat rolls having a flat surface to obtain an apparent density of 270 g / cm. 3 was granted.

[0097] After that, the nonwoven fabric that had completed the calendering process was passed through a water jet to apply pressure to the nonwoven fabric in the order of pressure intensity: lower (low: 70 bar) - upper (high: 250 bar) - lower (low: 50 bar). The thickness of the nonwoven fabric was adjusted by adjusting the water pressure in stages to produce the final spunbond nonwoven fabric (weight per unit area 90 g / m 2 , Thickness: 0.33mm).

[0098] The nonwoven fabric thus produced was tufted (Cut type, 64 / 5 gauge in inch, 13 / 1 stitch in inch, polypropylene carpet yarn (BCF; Bulky Continuous Filament) 1200 denier, pile yarn height 4 mm), and the back side of the tufting was heat treated at 235°C to fix the carpet yarn (BCF yarn) and produce a carpet. The tufted sample was used to measure the pull-out strength.

[0099] [Example 2] A spunbond nonwoven fabric and a carpet were produced in the same manner as in Example 1, except that the composite ratio of matrix:binder was changed to 80 wt%:20 wt%.

[0100] [Comparative Example 1] A spunbond nonwoven fabric and a carpet were produced in the same manner as in Example 1, except that the filament cross-sectional shape was changed to an orange shape and a circular shape rather than a split yarn.

[0101] [Comparative Example 2] A spunbond nonwoven fabric and a carpet were produced in the same manner as in Example 1, except that the binder material was changed to nylon 6.

[0102] [Comparative Example 3] A spunbond nonwoven fabric and a carpet were produced in the same manner as in Example 1, except that the composite ratio of matrix:binder was changed to 50 wt%:50 wt%.

[0103] [Comparative Example 4] A spunbond nonwoven fabric and a carpet were produced in the same manner as in Example 1, except that the composite ratio of matrix:binder was changed to 90 wt%:10 wt%.

[0104] [Comparative Example 5] A spunbond nonwoven fabric and a carpet were produced in the same manner as in Example 1, except that the spinning speed was set to 6,000 m / min.

[0105] [Comparative Example 6] A spunbond nonwoven fabric and a carpet were produced in the same manner as in Example 1, except that the spinning speed was set to 2,500 m / min.

[0106] [Comparative Example 7] A spunbond nonwoven fabric and a carpet were produced in the same manner as in Example 1, except that the produced nonwoven fabric was not subjected to the three stages of pressure, but was only subjected to water punching at a water pressure of 294 bar.

[0107] [Test example] For each of the Examples, Reference Examples, and Comparative Examples, physical properties were measured by the measurement methods for the following evaluation items, and the results are shown in Table 1.

[0108] 1.Division rate (%) The cross section of the nonwoven fabric was photographed with a microscope at a magnification of 200 times (×200), and the division ratio was calculated from 10 photographs (10ea) according to the following formula 1.

[0109] [Formula 1] Split rate (%) = (number of split filaments) / (number of split filaments + number of unsplit filaments) x 100

[0110] (In formula 1, The number of split filaments and the number of unsplit filaments are the numbers of split and unsplit filaments observed in a photograph of a cross section of a nonwoven fabric measuring 3 mm x 3 mm taken with a microscope at a magnification of x200, and the split rate is the average value of 10 photographs.

[0111] 2.Room temperature strength (kgf / 5cm) The room temperature strength was measured using the standard test method according to KS K 0521.

[0112] Specifically, a test piece measuring 5 cm x 20 cm in width x length was clamped between a jig measuring 5 cm x 5 cm at the top and bottom using Instron's measuring equipment, and then measured at a tensile speed of 200 mm / min.

[0113] 3. Hot strength (kgf / 3cm), hot elongation (%) The hot strength and hot elongation were measured using the standard test method according to KS K 0521.

[0114] Specifically, a test piece measuring 3cm x 10cm was clamped between a jig measuring 5cm x 5cm on the top and bottom using Instron's measuring equipment, and then preheated at 180℃ for 3 minutes in a hot chamber and measured at a tensile speed of 200mm / min.

[0115] 4. Pull-out strength (%) As described above, the nonwoven fabric was tufted (cut type, 64 / 5 gauge in inch, 13 / 1 stitch in inch, pile height 4 mm), and then the back side of the tufting was heat treated to fix the carpet yarn (BCF yarn) to produce a tufted sample.

[0116] The samples thus prepared were tufted according to the KS K ISO 4919 (Carpet - Tuft Pull-Out Strength Measurement) standard, and one pile to be measured was fixed to a measuring device. The loops on both sides adjacent to the loop to be measured were cut. Then, an Instron measuring device was used to measure the pile to be measured, and the peak strength value was recorded when the pile was pulled perpendicular to the sample. This process was repeated five times and the average value was taken. Three samples were prepared for testing and repeatedly evaluated.

[0117] [Table 1]

[0118] From the results in Table 1, it was confirmed that Examples 1 and 2 had a high split ratio and excellent room temperature strength, hot strength and hot elongation due to the inclusion of a spunbond nonwoven fabric acting as latex, compared to Comparative Examples 1 to 7. In addition, the Examples had excellent pull-out strength of 2.0 (kgf) or more.

[0119] On the other hand, Comparative Example 1 used a nonwoven fabric having a circular cross section and not divided, and therefore had poor mechanical properties, particularly a poor pull-out strength of 1.2 kfg.

[0120] In addition, in Comparative Example 2, since nylon was used as a binder, the function of latex could not be achieved, and both the mechanical properties and the pull-out strength were poor.

[0121] In the comparative examples 3 and 4, the contents of the matrix and binder materials were outside the ranges of the present specification, so the splitting rate was poor or the fibers were not split at all, the nonwoven fabric was not well formed, and it was difficult to manufacture the carpet.

[0122] As shown in Table 1, in Comparative Examples 5 and 6, the spinning speed was outside the range of the present invention, and therefore nonwoven fabrics could not be produced due to filament breakage in the drawing stage and shrinkage during thermal bonding. In Comparative Example 7, the high-pressure water jet was applied only in a single stage, and the split ratio was lower than in Examples 1 and 2, resulting in reduced strength, elongation, and pull-out strength.

Claims

1. The fiber web comprises a composite filament having a form of a split yarn containing 60 to 80% by weight of polyester filaments having a melting point of 250° C. or more and 20 to 40% by weight of copolymer filaments having a melting point of 170° C. or less, The split ratio of the composite filament according to the following formula 1 is 50% or more, It has a room temperature strength of 18 kgf / 5 cm or more, a hot strength of 4.0 kgf / 3 cm or less, and a hot elongation of 80% or more according to the standard test method of KS K 0521, According to the standard test method of KS K 0521, the room temperature strength was measured by clamping a test piece having a size of 5 cm x 20 cm between a jig having a size of 5 cm x 5 cm at the top and bottom using a measuring device manufactured by INSTRON, and then measuring the test piece at a tensile speed of 200 mm / min. The hot strength and hot elongation of the spunbond nonwoven fabric according to the standard test method of KS K 0521 were measured by clamping a test piece having a size of 3 cm x 10 cm (horizontal x vertical) between a jig having a size of 5 cm x 5 cm (upper and lower) using a measuring device manufactured by INSTRON, preheating the test piece at 180°C for 3 minutes, and then measuring the test piece at a tensile speed of 200 mm / min using a hot chamber. [Formula 1] Composite filament split rate (%) = (number of split composite filaments) / (number of split composite filaments + number of unsplit composite filaments) x 100 (In formula 1, The number of split composite filaments and the number of unsplit composite filaments are the numbers of split and unsplit filaments observed in a photograph of the cross section of the nonwoven fabric taken with a microscope (SEM) at a magnification of 200 times (×200), and the split rate is the average value of 10 photographs.

2. 2. The spunbond nonwoven fabric according to claim 1, wherein the nonwoven fabric has a room temperature strength of 19 kgf / 5 cm or more, a hot strength of 3.0 kgf / 3 cm or less, and a hot elongation of 81% or more, as measured by the standard test method of KS K 0521.

3. The spunbond nonwoven fabric according to claim 1 , wherein the split ratio of the composite filaments is 54% or more.

4. The spunbond nonwoven fabric according to claim 1, wherein the cross section of the composite filament before splitting is a circle divided into 8 to 64 parts.

5. The spunbond nonwoven fabric according to claim 1, wherein the composite filaments have an average diameter before splitting of 22 to 31 μm and a fineness of 5.0 to 9.0 denier.

6. The spunbond nonwoven fabric according to claim 1, wherein the polyester is at least one selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, and recycled raw materials thereof, and contains a polyester polymer having an intrinsic viscosity (IV) of 0.60 to 0.90 dl / g and a melting point of 250°C or higher.

7. The spunbond nonwoven fabric according to claim 1, wherein the copolymer filaments comprise at least one selected from the group consisting of polyolefins having a melting point of 170° C. or less and a melt index (MI) of 15 to 25 g / 10 min (ASTM 1238, 190° C.).

8. 60-80 wt % of polyester filaments having a melting point of 250° C. or more and 20-40 wt % of copolymer filaments having a melting point of 170° C. or less and a melt index (MI) of 15-25 g / 10 min (ASTM 1238, 190° C.) are spun through a multi-segment composite spinneret and drawn to prepare composite filaments having a split yarn form; laying up the composite filaments to form a fibrous web; bonding the fibrous webs by thermal bonding; and splitting the filaments in the thermally bonded web; The step of splitting the filament is performed using a water jet, After the step of splitting the filaments in the thermally bonded web, the split rate of the composite filaments according to the following formula 1 is 50% or more: [Formula 1] Composite filament split rate (%) = (number of split composite filaments) / (number of split composite filaments + number of unsplit composite filaments) x 100 (In formula 1, The number of split composite filaments and the number of unsplit composite filaments are the numbers of split and unsplit filaments observed in a photograph of the cross section of the nonwoven fabric taken with a microscope (SEM) at a magnification of 200 times (×200), and the split rate is the average value of 10 photographs.

9. The step of producing the composite filament comprises: The method for producing a spunbonded nonwoven fabric according to claim 8, further comprising the step of adjusting the fineness of the composite filaments so that the composite filaments have an average diameter of 22 to 31 μm and a fineness of 5.0 to 9.0 denier prior to the step of splitting the filaments in the thermally bonded web.

10. The method for producing a spunbonded nonwoven fabric according to claim 8, wherein the cross section of the composite filament before splitting is a circle divided into 8 to 64 parts.

11. The method for producing a spunbonded nonwoven fabric according to claim 8, wherein the stretching is carried out under conditions of 3,000 m / min to 5,000 m / min.

12. A carpet comprising the spunbond nonwoven fabric according to any one of claims 1 to 7.

13. The pull-out strength according to the standard test method of KS K ISO 4919 is 2.0 (kgf) or more, The carpet of claim 12 used as a flooring material in an automobile.

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