Core-sheath type spunbond nonwoven fabric and its manufacturing method

Abstract

The present invention provides a sheath-core spunbond nonwoven fabric having excellent mechanical properties and improved heat resistance and chemical resistance, the sheath being made of a polyphenylene sulfide material, and a core being made of a high-melting-point polyester material, and a method for continuously producing a sheath-core nonwoven fabric made of a polyphenylene sulfide material by the spunbonding method.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority based on Korean Patent Application No. 10-2020-0186036 filed on December 29, 2020, and Korean Patent Application No. 10-2021-0189933 filed on 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 core-sheath type spunbonded nonwoven fabric having excellent mechanical properties and improved heat resistance and chemical resistance, and a method for producing the same. [Background technology]

[0003] Polyphenylene sulfide (PPS) is a crystalline engineering plastic with a main chain structure in which sulfur is bonded to a benzene ring, and exhibits excellent chemical and heat resistance.

[0004] Nonwoven fabrics made from polyphenylene sulfide are mainly produced by melt spinning polyphenylene sulfide into fibers (filament or staple), followed by a wet-laid nonwoven fabric process, or by carding the staple fibers and then a dry nonwoven fabric process using a bonding process (needle punching or thermal bonding).

[0005] The commercial nonwoven fabrics made of polyphenylene sulfide are mainly manufactured using staple fibers. However, the polyphenylene sulfide has problems such as reduced stability during the spinning process due to excessive crystallization during spunbond spinning, and reduced mechanical properties due to insufficient thermal adhesion. In addition, conventional polyphenylene sulfide nonwoven fabrics are expensive products compared to PET fibers and lack price competitiveness.

[0006] The spunbond nonwoven fabrics made of PET lack heat resistance and chemical resistance and are prone to hydrolysis in hot and humid environments, making them difficult to use in flame-retardant / heat-resistant bag filters used in coal-fired power plants, cement factories, incineration facilities, environmental dust collection facilities, industrial waste treatment facilities, etc., as interior materials for automobile engine compartments and exhaust systems, and as liquid filtration filters that require durability against strong acids and strong alkalis. Summary of the Invention [Problem to be solved by the invention]

[0007] In order to solve the above problems, this specification provides a core-sheath spunbond nonwoven fabric which is made of a sheath made of a polyphenylene sulfide material and a core made of a high-melting point polyester material, and which not only has excellent mechanical properties but also has improved heat resistance and chemical resistance compared to conventional fabrics. It also provides a method for producing the same. [Means for solving the problem]

[0008] In this specification, 10 to 30% by weight of a sheath portion containing polyphenylene sulfide filaments having a melt viscosity of 700 to 3,000 poise (measured at 300°C and a shear rate of 1,000); and The nonwoven web includes a core-sheath type composite fiber having a core of 70 to 90% by weight of a polyester filament having a melting point of 250° C. or higher. Provided is a sheath-core spunbond nonwoven fabric.

[0009] In this specification, the sheath portion is made of a material having a melt viscosity of 700 to 3000 poise (1,000 at 300°C). l / s a step of conjugating polyphenylene sulfide filaments having a shear strength (measured at a shear rate of 1000 s / s) and a polyester having a melting point of 250°C or more as a core portion to obtain a sheath-core type conjugated filament having 10 to 30% by weight of a sheath portion containing polyphenylene sulfide filaments and 70 to 90% by weight of a core portion containing polyester filaments; Laying the sheath-core composite filaments on a continuous conveyor belt to form a fibrous web; and thermally bonding the fibrous web; The present invention provides a method for producing a sheath-core spunbonded nonwoven fabric, comprising the steps of:

[0010] The spunbond nonwoven fabric and its manufacturing method according to the embodiment of the invention will be described in detail below.

[0011] 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.

[0012] As used herein, the singular forms "a," "an," and "the" include the plural forms unless the context clearly dictates to the contrary.

[0013] As used herein, the meaning of "comprising" is to embody certain features, regions, constants, steps, operations, elements, components and / or components, and does not exclude the presence or addition of other particular features, regions, constants, steps, operations, elements, components and / or groups.

[0014] 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 numbers. 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.

[0015] The present invention will be described in detail below.

[0016] According to one embodiment of the present invention, the melt viscosity is 700 to 3000 poise (1,000 at 300°C). l / sThe present invention provides a sheath-core spunbond nonwoven fabric, comprising a nonwoven fabric web of sheath-core composite fibers comprising a mixture of 10 to 30% by weight of a sheath portion containing polyphenylene sulfide filaments having a melting point of 250°C or higher (measured at a shear rate of 100°C or higher); and 70 to 90% by weight of a core portion containing polyester filaments having a melting point of 250°C or higher.

[0017] The present inventors have continued their research to solve the problem of insufficient heat resistance and chemical resistance of conventional nonwoven fabrics made of staple fibers of polyphenylene sulfide material. As a result, they have confirmed that the heat resistance and chemical resistance of spunbond nonwoven fabrics can be improved by performing composite spinning in a sheath-core form using polyphenylene sulfide filaments and polyester filaments, thereby providing composite fibers in which the sheath is made of polyphenylene sulfide resin and the core is made of high melting point polyester resin, thereby completing the present invention.

[0018] Therefore, the core-sheath type spunbond nonwoven fabric according to the present invention can overcome the application limitations of nonwoven fabrics made from staple fibers, and by ensuring mechanical properties equal to or greater than existing nonwoven fabrics, various applications of polyphenylene sulfide-based nonwoven fabrics are possible.

[0019] The core-sheath type spunbonded nonwoven fabric means a spunbonded nonwoven fabric made of polyphenylene sulfide-containing conjugate spun fibers, and specifically, the sheath portion contains polyphenylene sulfide filaments and the core portion contains polyester filaments.

[0020] Specifically, the core-sheath spunbond nonwoven fabric includes a fiber web formed by composite spinning of a sheath portion including polyphenylene sulfide filaments having specific parameter properties and a core portion including polyester filaments having a high melting point of 250°C or higher.

[0021] The polyphenylene sulfide filament has a melt viscosity of 700 to 3000 poise (1,000 at 300°C). l / s More specifically, the melt viscosity of the polyphenylene sulfide filament is 700 to 2500 poise or 700 to 1000 poise (1,000 at 300°C). l / s If the melt viscosity is less than 700 poise, the mechanical properties of the spun filaments are reduced, causing yarn breakage and reducing spinnability, resulting in a problem of reduced uniformity of the nonwoven web, whereas if the melt viscosity is more than 3000 poise, the pressure in the spin pack increases, reducing the extrusion rate and thus reducing productivity.

[0022] Moreover, as the polyphenylene sulfide, linear PPS having a melting point of 275°C or higher, or a melting point of 275 to 285°C, can be used.

[0023] Generally, PPS is classified into crosslinked PPS, which is heat cured during polymerization, and linear PPS, which is not heat cured. The crosslinked PPS has a natural brown color, and the linear PPS has a natural beige or light gray color. Among them, the linear PPS is more advantageous for fiber production than the crosslinked PPS. Therefore, the polyphenylene sulfide filament is preferably made of the linear PPS. Hereinafter, unless otherwise specified, PPS means the linear PPS.

[0024] Specifically, the polyphenylene sulfide filament may contain polyphenylene sulfide having a melting point of 275°C or higher, a weight average molecular weight (Mw) of 30,000 to 90,000 g / mol as measured by GPC (gel permeation chromatography), and a crystallization speed of 60 to 80 seconds (measured at 240°C). The use of polyphenylene sulfide having such physical properties is advantageous in terms of ensuring mechanical properties and processability. The melt viscosity is 1,000 at 310°C using an apparatus having a piston diameter of 12 mm and a nozzle size of 20 mm (L) x 1 mm (D). l / s The value was measured at a shear rate of 100 / s.

[0025] According to one embodiment, the polyphenylene sulfide filaments are linear polyphenylene sulfide filaments having a melting point of 275 to 285°C, a weight average molecular weight (Mw) of 40,000 to 60,000 g / mol as measured by GPC (gel permeation chromatography), and a crystallization speed of 60 to 80 seconds (measured at 240°C).

[0026] By including polyphenylene sulfide filaments having such properties in the sheath of a core-sheath type spunbond nonwoven fabric, the spinnability is stable and excellent during spunbond spinning, and therefore excellent mechanical properties can be ensured.

[0027] More specifically, by using the polyphenylene sulfide filament (PPS component) in the sheath, it is possible to produce an economical product that has the excellent properties of PPS while minimizing the use of expensive PPS. In addition, by containing PPS having the above physical properties in the sheath, it is possible to reduce breakage of PPS fibers during high-speed spunbond spinning and improve spinning stability.

[0028] In this specification, the weight average molecular weight of a polymer means a weight average molecular weight in terms of polystyrene measured by the GPC method. In the process of measuring the weight average molecular weight in terms of polystyrene measured by the GPC method, a commonly known analyzer, a detector such as a refractive index detector, and an analytical column are used, and commonly applied temperature conditions, solvents, and flow rates can be applied. Specific examples of the measurement conditions include a temperature of 210° C., a 1-chloronaphthalene solvent, and a flow rate of 1 mL / min.

[0029] The polyester filaments are made of polyester having a melting point of 250°C or higher, or from 250 to 280°C.

[0030] For example, the polyester having a melting point of 250° C. or more may include one or more polymers selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, and polynaphthalene terephthalate. Specifically, the polyester filament may include polyethylene terephthalate (PET) having a melting point of 250° C. or more.

[0031] The polyester filament has an intrinsic viscosity (IV) of 0.6 dl / g or more and 0.7 dl / g or less, a crystallization rate of 300 to 500 seconds (measured at 210°C), a weight average molecular weight (Mw) of 50,000 to 65,000 g / mol measured by GPC (gel permeation chromatography), a melt flow index of 40 to 60 g / 10 min or 45 to 50 g / 10 min (measured at 280°C with a load of 2.06 kg), and a melt viscosity of 400 to 600 poise (measured at 1,000 to 2,000 poise at 300°C). l / s The polyester may include a polyester having a shear strength measured at a shear rate of 100 .mu.m.

[0032] Only by using the polyethylene terephthalate filament having the above physical properties as the core material can the fiber be blended with the sheath to provide excellent flame retardancy, high chemical resistance, and long-term stability against heat.

[0033] The physical properties of the polyphenylene sulfide filaments and polyester filaments are shown after drying in an inert gas at a temperature of 120 to 130° C. for 9 to 11 hours.

[0034] The denier and cross-sectional shape of the polyphenylene sulfide filaments and the polyester filaments are not particularly limited. As a non-limiting example, the filaments may each have a denier of 1 to 10 D and a circular cross section.

[0035] On the other hand, the fiber web contained in the core-sheath type spunbonded nonwoven fabric is composed of a sheath portion containing 10 to 30% by weight of the polyphenylene sulfide filaments, and a core portion containing 70 to 90% by weight of the polyester filaments.

[0036] If the content of the polyphenylene sulfide filaments in the sheath exceeds 30 wt % relative to the total weight of the composite fiber, problems may occur such as reduced stability in the spinning process, poor thermal adhesion due to excessive crystallization of PPS, and reduced mechanical properties. In addition, the use of a large amount of expensive PPS may increase production costs and reduce the economic viability of the nonwoven fabric.

[0037] In addition, if the polyphenylene sulfide filaments in the sheath portion are 10% by weight or less based on the total weight of the composite fiber, the core portion may become eccentric to one side of the fiber during filament spinning, or the core portion may become exposed to the fiber surface, which may reduce the heat resistance and chemical resistance of the nonwoven fabric.

[0038] Therefore, if the polyphenylene sulfide filaments in the sheath portion are configured to be 10 to 30% by weight, the above problems can be solved, and at the same time, it is possible to manufacture functional nonwoven fabrics that can replace existing products and develop new product groups.

[0039] In order to ensure the shape stability of the fiber web, the polyester filaments are contained in the fiber web in an amount of 70% by weight or more and 90% by weight or less.

[0040] In order to ensure excellent mechanical properties, the polyphenylene sulfide mixed fiber spunbonded nonwoven fabric has a fiber density of 70 to 150 g / m 2 , or 80-120g / m 2 , or 90-110g / m 2 The weight per unit area may be 1.0 to 1.0 mm.

[0041] The core-sheath type spunbond nonwoven fabric contains a composite fiber web formed by composite spinning of the polyphenylene sulfide filaments and the polyester filaments, and thus can have excellent mechanical properties as well as improved heat resistance and chemical resistance compared to conventional materials.

[0042] For example, the core-sheath type spunbond nonwoven fabric has a fiber density of 100 g / m 2 Based on the weight per unit area, the liquid resistance is 96% or more according to the standard test method of KS K ISO TR 12960:2011, and the water resistance is 96% or more according to the standard test method of KS K 0936:2007. minutes The resistance to dissolution is 97% or more. 、 The thermal shrinkage rate is 0.5% or less (measured by the length of shrinkage in the machine direction (MD) and cross direction (CD) of a nonwoven fabric test piece of 30 cm x 30 cm with a 20 cm x 20 cm pattern drawn on it, after heat-treating it in an oven at 220°C for 3 minutes), and the number of yarn breakages per hour (measured by the number of times a filament breaks when spun for 1 hour during the spunbond manufacturing process) is less than 1.

[0043] The core-sheath type spunbond nonwoven fabric has a fiber density of 100 g / m 2 Based on the weight per unit area, it may have a tensile strength in the machine direction (MD) of 20.0 kgf / 5 cm or more and a tensile strength in the cross direction (CD) of 20.0 kgf / 5 cm or more according to the standard test method of KS K 0521, and may have a circular cross section.

[0044] As a specific example, the core-sheath type spunbond nonwoven fabric has a density of 100 g / m 2 Based on the weight per unit area, the liquid resistance according to the standard test method of KS K ISO TR 12960:2011 can be 96% or more, or 96.5 to 99.5%.

[0045] The core-sheath type spunbond nonwoven fabric has a fiber density of 100 g / m 2 Based on the weight per unit area, the water content was measured according to the standard test method of KS K 0936:2007. minutes The reactivity may be greater than 97% or between 97% and 99%.

[0046] The core-sheath type spunbond nonwoven fabric has a density of 100 g / m 2 The heat shrinkage rate may be 0.5% or less, or 0.1 to 0.5% based on the weight per unit area (weight per unit area). (A nonwoven fabric test piece measuring 30 cm x 30 cm with a pattern measuring 20 cm x 20 cm is heat-treated in an oven at 220°C for 3 minutes, and then the average length of the heat-treated nonwoven fabric test piece shrunk in the machine direction (MD) and cross direction (CD) is measured, the average value being the average of three measurements).

[0047] The core-sheath type spunbond nonwoven fabric has a density of 100 g / m 2 Based on the weight per unit area, it exhibits less than one breakage per hour (a measurement of the number of times a filament breaks during one hour of spinning during the spunbond manufacturing process), ensuring excellent spinnability.

[0048] On the other hand, according to another embodiment of the invention, The sheath has a melt viscosity of 700 to 3,000 poise (1,000 at 300°C). l / s a composite melt spinning process of polyphenylene sulfide filaments having a shear rate of 100° C. or more and a polyester having a melting point of 250° C. or more as a core portion to obtain a sheath-core composite filament having a sheath portion of 10 to 30% by weight containing polyphenylene sulfide filaments and a core portion of 70 to 90% by weight containing polyester filaments; Laying the sheath-core composite filaments on a continuous conveyor belt to form a fibrous web; and thermally bonding the fibrous web; The present invention provides a method for producing a sheath-core spunbond nonwoven fabric, comprising:

[0049] The core-sheath spunbond nonwoven fabric according to the present specification includes a fiber web formed by conjugating polyphenylene sulfide filaments in the sheath and polyester filaments in the core under certain conditions, and is produced by a spunbond method.

[0050] In the spunbonding method, the polyphenylene sulfide and the polyester are each independently melted and spun through one mixed fiber spinneret in which the number of extrusion holes for different resins can be adjusted, and the polyphenylene sulfide filaments and polyester filaments obtained by the melt spinning are mixed to obtain the core-sheath type composite filaments.

[0051] Alternatively, in the spunbonding method, the polyphenylene sulfide of the sheath portion and the polyester of the core portion are each independently melted and spun through a separate spinneret, and the polyphenylene sulfide filaments of the sheath portion and the polyester filaments of the core portion obtained by the melt spinning are mixed to obtain the sheath-core type composite filament.

[0052] In addition, the method for producing the core-sheath type spunbonded nonwoven fabric can be carried out using a continuous extruder, and can effectively continuously produce a nonwoven fabric having excellent mechanical properties, heat resistance, and chemical resistance.

[0053] Specifically, according to the present specification, a method for producing a sheath-core spunbonded nonwoven fabric can be provided, which comprises the steps of: conjugating PPS having a melting point of 275°C or higher with polyester having a melting point of 250°C or higher; forming a fiber web from the sheath-core composite filaments; and thermally bonding the fiber web.

[0054] The filaments formed by the composite spinning may have a sheath and core structure, in which case the PPS forms the sheath component of the sheath and core structure, and the PET forms the core component of the sheath and core structure.

[0055] Here, the specific details regarding the configuration of the polyphenylene sulfide of the sheath portion and the polyester of the core portion are substituted for the details regarding the core-sheath type spunbond nonwoven fabric described above.

[0056] As described above, all of the raw materials used for the sheath and core can be used after drying in an inert gas, for example, in a nitrogen atmosphere, at a temperature of 120 to 130°C for 9 to 11 hours.

[0057] For example, in the case of polyester (specifically, PET) used as the material for the core, a drying process is carried out to prevent a decrease in molecular weight due to hydrolysis of the polymer and to equalize the difference in molecular weight between chips. Specifically, the drying process allows the core material to be used with its moisture content controlled to 100 ppm or less.

[0058] In addition, in the case of PPS used as the material of the sheath, although it has low hygroscopicity and has hydrolytic stability and thermal safety at high temperatures, a small amount of moisture can cause deterioration in physical properties and spinning stability. Therefore, by carrying out the drying process of the PPS, it is possible to prevent deterioration in physical properties and spinning stability of PPS caused by a small amount of moisture.

[0059] The core-sheath type composite filament has a melt viscosity of 700 to 3,000 poise (1,000 at 300°C). l / s The fiber comprises 10 to 30% by weight of a sheath portion containing polyphenylene sulfide filaments having a melting point of 250° C. or higher (measured at a shear rate of 100° C.), and 70 to 90% by weight of a core portion containing polyester filaments having a melting point of 250° C. or higher.

[0060] In the conjugate melt spinning of the sheath and core components, each material is fed into a continuous extruder, melted at a temperature 10 to 40°C higher than the melting point of the raw material, and then sheath-core conjugate spinning is performed. By such a method, each component is effectively melted, and the sheath-core conjugate spinning is performed continuously and more smoothly.

[0061] The composite spinning temperature may be 290°C to 320°C.

[0062] Also, the method may further include a step of solidifying the core-sheath type composite filaments before forming a fiber web.

[0063] The step of forming the fiber web may include the steps of drawing the core-sheath type composite filaments formed by the composite spinning, opening the drawn composite filaments, and stacking the opened composite filaments.

[0064] In other words, the filaments discharged by the composite melt spinning are solidified with cooling air, passed through a drawing device using high-pressure air, and then spread and laminated to form a fiber web composed of core-sheath type composite fibers.

[0065] Specifically, the solidification is carried out using cooling air in a quenching conditioner having a temperature of 25 to 35° C. or 25 to 30° C. If the temperature of the quenching conditioner is less than 25° C., there is a problem that it is impossible to manufacture a nonwoven fabric due to thread breakage during the spinning process, and if the temperature is 35° C. or higher, there is a problem that the temperature is too high and cooling is not performed well, making uniform cooling difficult, or the fibers are not cooled sufficiently, resulting in increased thread breakage.

[0066] The stretching is performed at 1 kgf / cm 2 or more or 1-4kgf / cm 2 This is done using an air stretching device under pressure conditions of 1000 psi.

[0067] The core-sheath type composite filaments are layered on a continuously moving conveyor belt (eg, a metal net) by a conventional fiber spreading method such as electrostatic charging, impact plate method, or air current diffusion method to form a fiber web.

[0068] The step of spreading the drawn composite filaments may include discharging the drawn composite filaments and collecting the spread filaments on a conveyor belt.

[0069] The fiber web is then bonded by thermal bonding to provide a core-sheath type spunbonded nonwoven fabric containing the polyphenylene sulfide.

[0070] In this manner, the composite filaments collected on the conveyor belt are laminated to form a fiber web, which is then thermally bonded to produce the spunbonded nonwoven fabric of the present invention.

[0071] Specifically, the thermal bonding is performed using a calendar roll or hot air method, and is performed in a temperature range that allows the polyethylene filaments to be fixed by thermal bonding.

[0072] More specifically, the thermal bonding may be performed by a calendering method in which the fibrous web is passed between heated rollers under pressure, or by a hot air method in which hot air is passed over the web.

[0073] According to one embodiment of the present invention, a preferred embodiment of the method for producing the core-sheath type spunbonded nonwoven fabric is as follows.

[0074] First, PPS and PET resins having the above-mentioned physical properties are melted in their respective extruders, and then extruded in accordance with the weight ratio of sheath / core. Composite fibers are spun from a core-sheath type composite spinneret with a hole diameter of φ0.4 mm to φ0.6 mm at a spinning temperature of 290°C to 320°C.

[0075] Next, the fiber discharged from the spinneret is solidified by Quenching Air after the temperature of the Quenching Conditioner is set to 25°C or higher or 25 to 35°C, and then the fiber is passed through an ejector installed at a distance of 1,500 mm from the spinneret.

[0076] Next, 1.0 kgf / cm 2 The method of drawing filaments by ejecting the drawing air from an ejector is preferred in that it is possible to efficiently control the crystallization of the PPS fiber portion and improve the stability of the spinning process.

[0077] The drawn and jetted multifilaments are then collected on a conveyor belt to form a web, and the resulting web is heat bonded to produce a nonwoven fabric.

[0078] The core-sheath spunbond nonwoven fabric provided as described above exhibits excellent mechanical properties and improved heat resistance and chemical resistance compared to conventional products, and is suitable for use in flame-retardant / heat-resistant bag filters for use in coal-fired power plants, cement factories, incineration facilities, environmental dust collection facilities, industrial waste treatment facilities, and the like, as interior materials for automobile engine compartments and exhaust systems, and as liquid filtration filters that require durability against strong acids and strong alkalis. Effect of the Invention

[0079] According to the present invention, it is possible to continuously produce a sheath-core type spunbonded nonwoven fabric made of a polyphenylene sulfide material having excellent mechanical properties, heat resistance, and chemical resistance, and a sheath-core type nonwoven fabric made of a polyphenylene sulfide material by a spunbonding method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0080] The functions and effects of the present invention will be described in more detail below through 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.

[0081] Example 1 An apparatus for manufacturing spunbond nonwoven fabric was prepared, which was equipped with two continuous extruders each having a screw and a heater, a mixed fiber spinneret capable of adjusting the number of discharge holes for different resins, a compressed air generator, an air stretching device, a metal net conveyor, a calendar roll, a hot air dryer, a tension adjusting device, and a winder.

[0082] Sheath (component A): The PPS raw material was dried in a nitrogen atmosphere at 130°C for 10 hours and used as the sheath. After drying, the melting point was 280°C, the weight average molecular weight (Mw) was 50,000, the melt viscosity was 700 Poise (300°C, shear rate 1000 l / s), and the crystallization speed (@240°C) was 70 seconds.

[0083] Core part (component B): The PET raw material was dried in a nitrogen atmosphere at 130℃ for 10 hours to be used as the component core part (Core). After drying, the melting point was 250℃, the weight average molecular weight (Mw) was 55,000, the melt viscosity was 450 (300℃, shear rate 1000 l / s), the melt flow index was 45~50g / 10min (@280℃), the intrinsic viscosity (IV) was 0.65dl / g, and the crystallization rate (@210℃) was 400 seconds.

[0084] 15% by weight of the PPS and 85% by weight of the PET were fed into a continuous extruder, melted by heating, and composite spun. Specifically, the PPS, which has a melting point of 280°C, was melted at 290°C, and the PET, which has a melting point of 250°C, was melted at 284°C, and then core-sheath composite spun.

[0085] At this time, the composite filaments formed after drawing were at a level of 3 to 9 denier, and were discharged in a weight ratio such that 15 wt % of PPS filaments and 85 wt % of PET filaments were spun.

[0086] The filaments spun through the spinneret were solidified by Quenching Air in an atmosphere of 25°C (i.e., Quenching Conditioner (Q / C) temperature 25°C), passed through an ejector installed at a distance of 1,500 mm from the spinneret, and stretched at 1.0 kgf / cm using an air stretching device. 2 By drawing with the above air, a core-sheath type composite filament having a circular cross section was obtained.

[0087] Next, the mixed composite filaments are laid on a continuously moving metal net conveyor by a conventional fiber spreading method, so that the weight per unit area of ​​the nonwoven fabric becomes 100 g / m. 2 A fiber web was formed so that the fiber web was formed as follows.

[0088] The formed fiber web was passed through upper and lower calendar rolls (nip pressure 30 N / cm) heated to 210° C. for thermal bonding to obtain a core-sheath type spunbonded nonwoven fabric.

[0089] Example 2 A nonwoven fabric was produced in the same manner as in Example 1, except that the amount of PPS added during composite spinning was 10 wt % and the amount of PET added was 90 wt %.

[0090] Example 3 A nonwoven fabric was produced in the same manner as in Example 1, except that the amount of PPS added during composite spinning was 30 wt % and the amount of PET added was 70 wt %.

[0091] Example 4 A nonwoven fabric was produced in the same manner as in Example 1, except that the temperature of the quenching conditioner (Q / C) during composite spinning was 35°C.

[0092] Example 5 A nonwoven fabric was produced in the same manner as in Example 1, except that the melt viscosity of the PPS during conjugate spinning was 3,000 Poise.

[0093] Reference example 1 Spinning was carried out in the same manner as in Example 1, except that the quenching conditioner (Q / C) temperature was 15° C. However, in this case, yarn breakage occurred during the spinning process, and a nonwoven fabric could not be produced.

[0094] Comparative Example 1 During composite spinning, spinning was performed in the same manner as in Example 1, except that the melt viscosity of the PPS was 4000 poise. However, in this case, the pack pressure increased excessively, and the experiment was stopped, so that a nonwoven fabric could not be produced.

[0095] Comparative Example 2 Spinning was carried out in the same manner as in Example 1, except that only PPS was spun without using PET. However, when the fiber consisted of only PPS, thread breakage occurred during the spinning process, and a nonwoven fabric could not be produced.

[0096] Comparative Example 3 A nonwoven fabric was produced in the same manner as in Example 1, except that the amount of PPS added during composite spinning was 5 wt % and the amount of PET added was 95 wt %.

[0097] Comparative Example 4 A nonwoven fabric was produced in the same manner as in Example 1, except that the amount of PPS added during composite spinning was 40 wt % and the amount of PET added was 60 wt %.

[0098] Comparative Example 5 For the sheath, PET having a melting point of 250° C. was used instead of PPS having a melting point of 280° C., and for the core, low-melting-point PET having a melting point of 214° C. was used instead of PET having a melting point of 250° C. In addition, composite spinning was performed in the same manner as in Example 1, except that the amount of the sheath was 85 wt % and the amount of the core was 15 wt %.

[0099] Comparative Example 6 During composite spinning, spinning was carried out in the same manner as in Example 1, except that the melt viscosity of the PPS was 650 Poise.

[0100] Reference example 2 Spinning was carried out in the same manner as in Example 1, except that the quenching conditioner (Q / C) temperature was 40° C. However, in this case, yarn breakage occurred during the spinning process, and a nonwoven fabric could not be produced.

[0101] [Test example] For the above Examples, Reference Examples, and Comparative Examples, the physical properties were measured by the following measurement methods for each evaluation item, and the results are shown in Table 1 or Table 2.

[0102] [Test Example 1. Melt Viscosity] Using an apparatus with a piston diameter of 12 mm and a die specification of 20 mm (L) × 1 mm (D), the melt viscosities of polyphenylene sulfide and polyethylene terephthalate were measured respectively under the condition of a shear rate of 1,000 l / s at 300 °C.

[0103] [Test Example 2. Tensile Strength Degree (kgf / 5 cm)] Using a universal testing machine from Instron, the tensile strength Degree was measured according to the standard test method of KS K 0521 (unit: kgf / 5 cm).

[0104] Specifically, for each nonwoven fabric of the Examples and Comparative Examples, after manufacturing test pieces with a size of 5 cm (width) × 20 cm (length) in the longitudinal and transverse (MD and CD) directions, the tensile strength Degree was measured at a tensile speed of 200 mm / min using a measuring device from Instron.

[0105] [Test Example 3. Liquid Resistance (KS K ISO TR 12960:2011)] Tensile strength Degree Test pieces of the same size as those used for the measurement of tensile strength were prepared. Subsequently, for inorganic acid (Method A) and inorganic base (Method B), control test pieces and damaged test pieces were manufactured under the following treatment conditions, and using the test method of KS K 0743:2016, the ratio of the tensile strength Degree (kgf / 5 cm) of the damaged test piece to that of the control test piece was calculated to evaluate the liquid resistance.

[0106] Processing conditions (1) Method A Control test piece - Immersed in 0.025 M sulfuric acid at (60 ± 1) °C for 1 h Damaged test piece - Immersed in 0.025 M sulfuric acid at (60 ± 1) °C for 144 h

[0107] (2) Method B Control specimen - Calcium hydroxide [Ca(OH) 2 ], saturated suspension of 2.5 g per liter, (60±1)℃, immersion for 1 h Damaged specimen - Calcium hydroxide [Ca(OH) 2 ], saturated suspension of 2.5 g per liter, (60±1)℃, 144 h immersion

[0108] [Test Example 4. Hydrolysis resistance (KS K 0936:2007)] Tensile strength Degree Test pieces of the same size as those used for the measurement were prepared. After that, in order to expose the spunbond nonwoven fabric to high-temperature water, a control test piece and a damaged test piece were prepared under the following treatment conditions, and the tensile strength of the damaged test piece was compared with that of the control test piece using the test method of KS K 0743:2016. Degree The ratio (kgf / 5cm) was calculated to evaluate hydrolysis resistance.

[0109] Processing conditions Control test piece - Water temperature: (80±1)℃, 1h treatment Damaged test piece - Water temperature: (80±1)℃, 28 days treatment

[0110] [Test Example 5. Heat shrinkage rate] A pattern of 20 cm x 20 cm was drawn on a nonwoven fabric test piece of MD x CD = 30 cm x 30 cm, and the test piece was heat-treated at 220°C for 3 minutes on a preheating plate using a Mathis Oven (Mathis Oven, DaeLim Starlet Co., Ltd.), and then removed. The heat shrinkage rate was calculated by measuring the length of the test piece that had shrunk compared to the length of the test piece before heat treatment.

[0111] [Test Example 6. Spinnability] The spinning stability during the production process of the spunbonded nonwoven fabrics produced in the above Examples, Reference Examples and Comparative Examples was evaluated by measuring the number of thread breaks during one hour of spinning.

[0112] Evaluation criteria If the thread breaks less than once per hour: Good (○) If the thread breaks 1 to 3 times per hour: Normal (△) If the number of thread breaks per hour is more than 3: Bad (X)

[0113] [Table 1]

[0114] [Table 2]

[0115] From the results in Tables 1 and 2, it was confirmed that the Examples, which contain PPS satisfying a specific melt viscosity as a sheath portion, contain high melting point PET as a core portion, and use a PPS content of 10 to 30% by weight, are superior in spinning stability and mechanical properties to the Comparative Examples. It was also confirmed that the Examples are superior to the Comparative Examples, with liquid resistance of 96% or more, hydrolysis resistance of 97% or more, and heat shrinkage of 0.5% or less.

[0116] In contrast, in the case of Reference Example 1, as described above, the temperature of the quenching conditioner during the solidification process after spinning was excessively low at 15°C, so spinning was not performed well, yarn breakage occurred, and a nonwoven fabric could not be produced.

[0117] In Comparative Example 1, the melt viscosity of the sheath material PPS was too high, so that the pressure of the spin pack increased and it was not possible to produce a nonwoven fabric, and the physical properties and spinnability of the nonwoven fabric could not be evaluated. In Comparative Examples 2 and 4, either because PPS was spun alone or because the amount of PPS added was too large, it was not possible to produce a nonwoven fabric due to thread breakage during the spinning process, and the physical properties and spinnability could not be evaluated. In Comparative Example 3, the content of the PPS was too low, so that the heat shrinkage rate was high, and the liquid resistance and hydrolysis resistance of the nonwoven fabric were poor compared to Examples 1 to 5. In Comparative Example 5, the sheath and core were formed only from PET material, so that the liquid resistance and hydrolysis resistance of the nonwoven fabric were poor compared to Examples 1 to 5.

[0118] In addition, in Comparative Example 6, where the melt viscosity range of PPS is 650 poise, which is outside the melt viscosity range of the PPS of the sheath portion according to the present invention, thread breakage occurred and it was impossible to produce a nonwoven fabric. Also, in Reference Example 2, where the quenching conditioner temperature is 40°C, which is outside the solidification temperature range of the present invention, thread breakage occurred and it was impossible to produce a nonwoven fabric.

Claims

1. 10 to 30 weight percent of a sheath portion containing polyphenylene sulfide having a melt viscosity of 700 to 3,000 poise (measured at 300° C. and a shear rate of 1,000 l / s); and A nonwoven web of core-sheath type composite filaments including 70 to 90% by weight of a core portion including a polyester having a melting point of 250° C. or more; The polyphenylene sulfide is The polyphenylene sulfide has a melting point of 275° C. or higher and a weight average molecular weight (Mw) of 30,000 to 90,000 g / mol as measured by gel permeation chromatography (GPC), A core-sheath spunbond nonwoven fabric having a heat shrinkage rate of 0.5% or less (measured by the length of shrinkage in the machine direction (MD) and cross direction (CD) of a nonwoven fabric test piece of 30 cm x 30 cm with a pattern of 20 cm x 20 cm drawn on it, after heat-treating the nonwoven fabric test piece in an oven at 220°C for 3 minutes).

2. 2. The core-sheath spunbond nonwoven fabric according to claim 1, wherein the polyester comprises a polyester having an intrinsic viscosity (IV) of 0.6 dl / g to 0.7 dl / g, a weight average molecular weight (Mw) of 50,000 to 65,000 g / mol as measured by GPC (gel permeation chromatography), a melt flow index of 40 to 60 g / 10 min or 45 to 50 g / 10 min (measured at 280° C. under a load of 2.06 kg), and a melt viscosity of 400 to 600 poise (measured at 300° C. under a shear rate of 1,000 l / s).

3. 2. The sheath-core spunbond nonwoven fabric of claim 1, wherein the polyester comprises polyethylene terephthalate.

4. It has a tensile strength in the machine direction (MD) of 20.0 kgf / 5 cm or more and a tensile strength in the cross direction (CD) of 20.0 kgf / 5 cm or more according to the standard test method of KS K 0521, and has a circular cross section; The core-sheath spunbond nonwoven fabric according to claim 1, wherein the standard test method of KS K 0521 is to prepare a test piece having a size of 5 cm wide x 20 cm long in the machine direction (MD and CD) and measure the test piece at a tensile speed of 200 mm / min. using a measuring device manufactured by Instron Corporation.

5. 70-150g / m ２ 2. The sheath-core spunbond nonwoven fabric of claim 1, having a weight per unit area of

6. A step of conjugating polyphenylene sulfide having a melt viscosity of 700 to 3,000 poise (measured at a shear rate of 1,000 l / s at 300° C.) as a sheath portion and polyester having a melting point of 250° C. or higher as a core portion, thereby obtaining a core-sheath type conjugated filament including 10 to 30% by weight of a sheath portion containing polyphenylene sulfide and 70 to 90% by weight of a core portion containing polyester; Laminating the sheath-core composite filaments on a continuous conveyor belt to form a fibrous web; and thermally bonding the fibrous web; Including, The polyphenylene sulfide is A polyphenylene sulfide having a melting point of 275° C. or higher and a weight average molecular weight (Mw) of 30,000 to 90,000 g / mol as measured by GPC (gel permeation chromatography) is used. The method further comprises a step of consolidating the core-sheath composite filaments prior to forming a fiber web, The method for producing a core-sheath spunbonded nonwoven fabric according to claim 1, wherein the solidification is carried out using cooling air in a quenching conditioner having a temperature of 25 to 35°C.

7. 7. The method for producing a sheath-core spunbonded nonwoven fabric according to claim 6, wherein the step of forming the fiber web includes the steps of drawing the sheath-core composite filaments formed by the composite spinning, opening the drawn composite filaments, and stacking the opened composite filaments.

8. The stretching is performed at 1 kgf / cm ２ The method for producing the core-sheath type spunbonded nonwoven fabric according to claim 7, which is carried out using an air stretching device under the above pressure conditions.

9. 7. The method for producing a core-sheath spunbond nonwoven fabric according to claim 6, wherein the polyester used has an intrinsic viscosity (IV) of 0.6 dl / g to 0.7 dl / g, a weight average molecular weight (Mw) of 50,000 to 65,000 g / mol as measured by GPC (gel permeation chromatography), a melt flow index of 40 to 60 g / 10 min or 45 to 50 g / 10 min (measured at 280° C. under a load of 2.06 kg), and a melt viscosity of 400 to 600 poise (measured at 300° C. under a shear rate of 1,000 l / s).

10. The method for producing a core-sheath type spunbonded nonwoven fabric according to claim 6 , wherein the thermal bonding is carried out using a calendar roll method or a hot air method.

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