Artificial leather and manufacturing method therefor

Abstract

The present invention relates to an artificial leather and a manufacturing method therefor. According to the present invention, the artificial leather and the manufacturing method therefor are provided, the artificial leather having a rich nap texture and excellent mechanical properties and being easily recyclable, thereby being environmentally friendly.

Description

Artificial leather and method of manufacturing the same

[0001] The present invention relates to artificial leather and a method for manufacturing the same.

[0002]

[0003] Tactile sensation is an important factor in determining the quality of suede-like artificial leather. The rich nap, similar to that of natural leather, is one of the reasons why artificial leather is used not only in the fashion and clothing sectors but also in various industries such as furniture and car seats.

[0004] In order to improve the tactile feel of artificial leather, it is important to ensure that microfibers form a dense nap on the surface and to minimize exposure of the polymer elastomer impregnated in the substrate layer between the nap on the surface.

[0005] Generally, in the case of suede-like artificial leather, there is a limitation in that the polymer elastomer is exposed between the surface naps during the napping process for forming nap on the surface.

[0006] However, the above-mentioned polymer elastomer differs in dyeing characteristics compared to the fiber material portion of artificial leather and exhibits relatively poor fastness. Therefore, if the above-mentioned polymer elastomer is exposed between the nap of the artificial leather surface, it has a negative effect on the appearance quality as well as the tactile feel.

[0007] Meanwhile, artificial leather is composed of composite materials made of various raw materials, and the bonding strength of each laminated layer is very high, making it difficult to separate them layer by layer. For this reason, devising methods for the reuse and recycling of artificial leather that has reached the end of its lifespan is one of the challenges facing this technology field.

[0008]

[0009] The present invention aims to provide an environmentally friendly artificial leather that is easy to recycle while possessing a rich nap and excellent mechanical properties.

[0010] And, the present invention is intended to provide a method for manufacturing the artificial leather.

[0011]

[0012] According to one embodiment of the invention,

[0013] A nonwoven fabric laminate having surface nap on one side and a substrate layer comprising a polymer elastomer impregnated on the nonwoven fabric laminate, and

[0014] It includes a thermoplastic resin coating layer laminated on the other side of the above-mentioned nonwoven fabric laminate;

[0015] The above nonwoven laminate comprises an upper nonwoven fabric having surface nap on one side, and a lower nonwoven fabric interlocked with another side on which surface nap is not formed on the upper nonwoven fabric.

[0016] The above-mentioned lower nonwoven fabric has a lower apparent density than the above-mentioned upper nonwoven fabric, and

[0017] The above lower nonwoven fabric is impregnated with the above polymer elastomer at a higher weight ratio than the above upper nonwoven fabric,

[0018] Artificial leather is provided.

[0019]

[0020] According to one embodiment, the polymer elastomer may be impregnated with a water-dispersible polyurethane.

[0021]

[0022] According to one embodiment, the thermoplastic resin coating layer may be formed by applying a solvent-free thermoplastic resin.

[0023]

[0024] According to one embodiment, the upper nonwoven fabric has a g / cm² of 0.200 to 0.250 g / cm² 3 It has an apparent density, and the above-mentioned nonwoven fabric has a density of 0.175 to 0.200 g / cm³ 3 It can have an apparent density.

[0025]

[0026] According to one embodiment, the absolute value of the apparent density difference between the upper nonwoven fabric and the lower nonwoven fabric is 0.02 to 0.07 g / cm² 3 It could be.

[0027]

[0028] According to one embodiment, the lower nonwoven fabric may comprise fibers having a fineness greater than or equal to that of the upper nonwoven fabric.

[0029]

[0030] According to one embodiment, the upper nonwoven fabric may comprise fibers having a fineness of 2.5 to 3.5 denier, and the lower nonwoven fabric may comprise fibers having a fineness of 3.5 to 5.5 denier.

[0031]

[0032] According to one embodiment, the upper nonwoven fabric and the lower nonwoven fabric each comprise a sea island-type fiber, and the sea island-type fiber may comprise 10 to 60 weight% of sea components and 40 to 90 weight% of island components.

[0033]

[0034] According to one embodiment, the upper nonwoven fabric and the lower nonwoven fabric may each have a thickness of 1.0 to 5.0 mm.

[0035]

[0036] According to one embodiment, the nonwoven fabric laminate has a g / cm³ of 0.200 to 0.240 g / cm³ 3 It may have an apparent density.

[0037]

[0038] According to one embodiment, the nonwoven laminate may comprise 15 to 35 weight percent of the polymer elastomer based on the weight of the nonwoven laminate.

[0039]

[0040] According to one embodiment, the polymer elastomer may be impregnated onto the nonwoven fabric laminate to have a weight gradient that increases from the upper nonwoven fabric toward the lower nonwoven fabric.

[0041]

[0042] According to another embodiment of the invention.

[0043] A step of providing an upper nonwoven fabric and a lower nonwoven fabric manufactured from sea-island type fibers,

[0044] A step of obtaining a nonwoven fabric laminate by interlacing the upper nonwoven fabric and the lower nonwoven fabric.

[0045] A step of obtaining a shrinkable fabric by heat-shrinking the above nonwoven fabric laminate,

[0046] A step of obtaining an impregnated cloth by immersing the shrink cloth in a solution containing a polymer elastomer,

[0047] A step of extracting sea components from the above sea-island type fiber,

[0048] A step of forming nap by grinding the surface of the upper nonwoven fabric, and

[0049] The method includes the step of forming a thermoplastic resin coating layer by applying a solvent-free thermoplastic resin to the back surface of the above-mentioned nonwoven fabric;

[0050] The above-mentioned lower nonwoven fabric has a lower apparent density than the above-mentioned upper nonwoven fabric, and

[0051] The above lower nonwoven fabric is impregnated with the above polymer elastomer at a higher weight ratio than the above upper nonwoven fabric,

[0052] A method for manufacturing the above artificial leather is provided.

[0053]

[0054] According to one embodiment, the solution containing the polymer elastomer is a water-dispersible polyurethane, and the solvent-free thermoplastic resin may be a solvent-free polyurethane resin formed from a reaction product of an isocyanate component and a polyol component.

[0055]

[0056] According to one embodiment, the upper nonwoven fabric is obtained by performing needle punching processing on a web formed of the sea-island type fibers with a needle penetration density of 2500 to 2700 PPSC (punch per square centimeter), a needle stroke per minute of 380 to 420 RPM, and a needle depth of 5.5 to 6.5 mm; and the lower nonwoven fabric can be obtained by performing needle punching processing on a web formed of the sea-island type fibers with a needle penetration density of 2300 to 2450 PPSC, a needle stroke per minute of 350 to 380 RPM, and a needle depth of 4.5 to 5.5 mm.

[0057]

[0058] According to the present invention, an environmentally friendly artificial leather having a rich nap and excellent mechanical properties, while being easy to recycle, and a method for manufacturing the same are provided.

[0059]

[0060] FIG. 1 is a grayscale image of a surface with nap formed in artificial leather according to Example 1 of the present specification, observed by magnifying it 60 times with an optical microscope.

[0061] FIG. 2 is a grayscale image of a surface with nap formed in artificial leather according to Example 2 of the present specification, observed by magnifying it 60 times with an optical microscope.

[0062] FIG. 3 is a grayscale image of a surface with nap formed in artificial leather according to Comparative Example 1 of the present specification, observed by magnifying it 60 times with an optical microscope.

[0063] In the grayscale images of the above drawings, the white areas or areas that are bright and close to white indicate parts where the polymer elastomer is exposed between the nap of the artificial leather surface.

[0064]

[0065] Hereinafter, artificial leather according to embodiments of the invention and a method for manufacturing the same will be described in more detail.

[0066]

[0067] Unless explicitly stated otherwise in this specification, technical terms are used merely to refer to specific embodiments and are not intended to limit the invention.

[0068] The singular forms used in this specification include plural forms unless the phrases clearly indicate otherwise.

[0069] As used in this specification, the meaning of “includes” specifies certain characteristics, regions, integers, steps, actions, elements, and / or components, and does not exclude the existence or addition of other specific characteristics, regions, integers, steps, actions, elements, components, and / or groups.

[0070] In this specification, terms including ordinal numbers, such as "first" and "second," are used for the purpose of distinguishing one component from another and are not limited by said ordinal numbers. For example, within the scope of the present invention, the first component may also be named the second component, and similarly, the second component may be named the first component.

[0071] As used herein, "denier" is a unit of fineness based on the mass (gram) per 9,000 meters of length of a single fiber strand. For example, 1 denier can be expressed as 1 g / 9,000 m, or 0.11 mg / m, or 0.11 tex.

[0072]

[0073] According to one embodiment of the invention,

[0074] A nonwoven fabric laminate having surface nap on one side and a substrate layer comprising a polymer elastomer impregnated on the nonwoven fabric laminate, and

[0075] It includes a thermoplastic resin coating layer laminated on the other side of the above-mentioned nonwoven fabric laminate;

[0076] The above nonwoven laminate comprises an upper nonwoven fabric having surface nap on one side, and a lower nonwoven fabric interlocked with another side on which surface nap is not formed on the upper nonwoven fabric.

[0077] The above-mentioned lower nonwoven fabric has a lower apparent density than the above-mentioned upper nonwoven fabric, and

[0078] The above lower nonwoven fabric is impregnated with the above polymer elastomer at a higher weight ratio than the above upper nonwoven fabric,

[0079] Artificial leather is provided.

[0080]

[0081] As a result of the inventors' research, it has been confirmed that artificial leather satisfying the above compositions can exhibit environmentally friendly characteristics by being easy to recycle while possessing a rich nap and excellent mechanical properties.

[0082] The artificial leather described above includes the nonwoven laminate, thereby allowing a higher weight ratio of polymeric elastomer to be impregnated onto the lower nonwoven fabric than onto the upper nonwoven fabric. That is, the polymeric elastomer is impregnated onto the nonwoven laminate such that there is a weight gradient from the upper nonwoven fabric toward the lower nonwoven fabric. Accordingly, during the napping process for forming nap on the surface of the artificial leather, the exposure of the polymeric elastomer between the naps on the surface can be minimized, and a rich nap texture and uniform color can be imparted to the surface of the artificial leather.

[0083] Furthermore, since the artificial leather comprises an environmentally friendly water-dispersible polyurethane applied as the polymer elastomer and a thermoplastic resin coating layer formed by applying a solvent-free thermoplastic resin, it is possible to reuse and recycle the artificial leather without separating it layer by layer while possessing excellent mechanical properties.

[0084]

[0085] The artificial leather described above comprises a nonwoven laminate having surface nap on one side and a substrate layer comprising a polymer elastomer impregnated on the nonwoven laminate.

[0086] The above nonwoven laminate comprises two or more nonwoven fabrics stacked sequentially. For example, the nonwoven laminate comprises an upper nonwoven fabric having surface nap on one side, and a lower nonwoven fabric interlocked with another side of the upper nonwoven fabric in which surface nap is not formed.

[0087] According to one embodiment, the lower nonwoven fabric has a lower apparent density than the upper nonwoven fabric. Accordingly, the lower nonwoven fabric may be impregnated with the polymer elastomer at a higher weight ratio than the upper nonwoven fabric.

[0088]

[0089] In this specification, the apparent density is a value calculated by the following formula by measuring the average thickness and average unit weight of the nonwoven fabric. For example, the smaller the apparent density, the larger the volume of the nonwoven fabric.

[0090] *Apparent density (g / cm³) 3 ) = [Average unit weight (g / m²) 2 ) / Average thickness (mm)] / 1000

[0091]

[0092] According to one embodiment, the upper nonwoven fabric has a g / cm² of 0.200 to 0.250 g / cm² 3 , or 0.210 to 0.250 g / cm³ 3 , or 0.210 to 0.240 g / cm³ 3 , or 0.220 to 0.240 g / cm³ 3 , or 0.220 to 0.235 g / cm³ 3 It may have an apparent density.

[0093] According to one embodiment, the lower nonwoven fabric has a g / cm² of 0.175 to 0.200 g / cm² 3 , or 0.180 to 0.200 g / cm³ 3 , or 0.180 to 0.190 g / cm³ 3 It may have an apparent density.

[0094] And, according to one embodiment, the absolute value of the apparent density difference between the upper nonwoven fabric and the lower nonwoven fabric is 0.02 to 0.07 g / cm³ 3 , or 0.03 to 0.07 g / cm³ 3 , or 0.03 to 0.06 g / cm³ 3 It may be desirable to be so.

[0095] As the upper nonwoven fabric and the lower nonwoven fabric satisfy the apparent density of the range described above and the absolute value of the difference therefrom, the lower nonwoven fabric may be impregnated with the polymer elastomer at a higher weight ratio than the upper nonwoven fabric. Preferably, the polymer elastomer may be impregnated on the nonwoven fabric laminate to have a weight gradient that increases from the upper nonwoven fabric toward the lower nonwoven fabric.

[0096] In order to enable the distribution of polymeric elastomers relatively localized on the lower nonwoven fabric to be expressed, it is preferable that the upper nonwoven fabric and the lower nonwoven fabric each satisfy the apparent density within the range described above. In particular, the absolute value of the apparent density difference is 0.02 g / cm³. 3 Above or 0.03 g / cm³ 3 It is desirable to be ideal.

[0097] However, if the absolute value of the above apparent density difference is too large, the uneven distribution of the polymer elastomer with respect to the above underlying nonwoven fabric may intensify, potentially leading to poor mechanical properties of the artificial leather. Therefore, the absolute value of the above apparent density difference is 0.07 g / cm³ 3 Less than or equal to 0.06 g / cm³3 It is desirable that it be less than or equal to this.

[0098]

[0099] According to one embodiment, in order to impregnate the lower nonwoven fabric with a higher weight ratio of the polymer elastomer than the upper nonwoven fabric, the lower nonwoven fabric may include fibers having a fineness greater than or equal to that of the upper nonwoven fabric.

[0100] According to one embodiment, the upper nonwoven fabric may comprise fibers having a fineness of 2.5 to 3.5 denier, or 2.7 to 3.5 denier, or 3.0 to 3.5 denier.

[0101] And, according to one embodiment, the lower nonwoven fabric may comprise fibers having a fineness of 3.5 to 5.5 denier, or 3.5 to 5.0 denier, or 3.5 to 4.5 denier.

[0102]

[0103] Preferably, the upper nonwoven fabric comprises fibers having a fineness of 2.5 to 3.5 denier, or 2.7 to 3.5 denier, or 3.0 to 3.5 denier; and 0.200 to 0.250 g / cm² 3 , or 0.210 to 0.250 g / cm³ 3 , or 0.210 to 0.240 g / cm³ 3 , or 0.220 to 0.240 g / cm³ 3 , or 0.220 to 0.235 g / cm³ 3 It may have an apparent density.

[0104] And, preferably, the lower nonwoven fabric comprises fibers having a fineness of 3.5 to 5.5 denier, or 3.5 to 5.0 denier, or 3.5 to 4.5 denier; and 0.175 to 0.200 g / cm² 3 , or 0.180 to 0.200 g / cm³ 3, or 0.180 to 0.190 g / cm³ 3 It may have an apparent density.

[0105]

[0106] By ensuring that the upper nonwoven fabric and the lower nonwoven fabric constituting the above nonwoven fabric laminate satisfy the relationship between fiber fineness and apparent density described above, the polymer elastomer can be impregnated in a higher weight ratio on the lower nonwoven fabric than on the upper nonwoven fabric. Preferably, the polymer elastomer can be impregnated on the nonwoven fabric laminate such that it has a weight gradient that increases from the upper nonwoven fabric toward the lower nonwoven fabric.

[0107]

[0108] According to one embodiment, it is preferable that the polymer elastomer be impregnated onto the nonwoven laminate by applying a water-dispersible polyurethane.

[0109] The above-mentioned water-dispersible polyurethane refers to a water-based urethane resin dispersed in water. Generally, polyurethane is used in a dissolved state in organic solvents, which is harmful to the human body and the environment and poses a risk of flammability from open flames. In contrast, the above-mentioned water-dispersible polyurethane facilitates the exhaust and disposal of waste liquid during use, thereby reducing the environmental burden, and enables the imparting of a flexible yet elastic texture.

[0110] The above polyurethane is a polymer compound having urethane bonds in its molecules, and can generally be formed by the reaction of a diisocyanate compound and a polyol.

[0111] The above water-dispersible polyurethane may include one or more polyurethanes selected from the group consisting of polycarbonate-based urethane, polyester-based urethane, polyacrylic-based urethane, polytetramethylene-based urethane, polycaprolactone-based urethane, polypropylene-based urethane, and polyethylene-based urethane.

[0112] According to one embodiment, the polyurethane included in the water-dispersible polyurethane may have a weight average molecular weight (Mw) of 250,000 to 350,000 g / mol. When the weight average molecular weight range of the polyurethane is satisfied, adhesion, wear resistance, and elasticity can be secured through the use of the water-dispersible polyurethane.

[0113] As long as the above weight average molecular weight is satisfied, the method of manufacturing the water-dispersible polyurethane is not particularly limited. For example, the water-dispersible polyurethane can be obtained by neutralizing a prepolymer having units derived from polyester polyol, diol, and diisocyanate with a neutralizing agent and then stirring with distilled water.

[0114] Commercially available products may be used as the above-mentioned water-dispersible polyurethane. For example, the above-mentioned water-dispersible polyurethane may include the EVAFANOL series and NEOSTECKER series manufactured by NICCA CHEMICAL, the HYDRAN series manufactured by DIC, or the SUPERFLEX series manufactured by DKS Co. Ltd.

[0115]

[0116] According to one embodiment, the upper nonwoven fabric and the lower nonwoven fabric may each include sea island type fibers.

[0117] The above-mentioned sea-island type fiber is composed of a first polymer and a second polymer with different solubility characteristics in a solvent.

[0118] The first polymer mentioned above is a sea component that dissolves and leaches out in a solvent, and may be a copolymer polyester or polystyrene. As an example, the first polymer is a copolymer polyester with excellent solubility in alkaline solvents.

[0119] The above copolymer polyester may be a copolymer of polyethylene glycol, polypropylene glycol, 1,4-cyclohexanedicarboxylic acid, 1,4-cyclohexanedimethanol, 1,4-cyclohexanedicarboxylate, 2,2-dimethyl-1,3-propanediol, 2,2-dimethyl-1,4-butanediol, 2,2,4-trimethyl-1,3-propanediol, adipic acid, and metal sulfonate-containing ester units or a mixture thereof, with polyethylene terephthalate as the main component.

[0120] The second polymer above may be polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), or polybutylene terephthalate (PBT) as a residual island component with relatively low solubility in solvents.

[0121] The above-mentioned sea island type fiber is formed by dissolving the first polymer, which is the sea component, into a solvent, thereby leaving only the second polymer, which is the island component, to form an ultrafine fiber. Therefore, in order to obtain the required ultrafine fiber, it is necessary to appropriately control the content of the first polymer, which is the sea component, and the second polymer, which is the island component.

[0122] According to one embodiment, in the sea-island type fiber, the first polymer, which is the sea component, is included in an amount of 10 to 60 weight%, or 20 to 50 weight%, or 20 to 40 weight%; and the second polymer, which is the island component, may be included in an amount of 40 to 90 weight%, or 50 to 80 weight%, or 60 to 80 weight%. For the formation of ultrafine fibers, it is preferable that the sea component be included in an amount of 10 weight% or more or 20 weight% or more. However, if the sea component is included in an excessive amount, the elution efficiency thereof may decrease and the physical properties of the ultrafine fibers may deteriorate. Therefore, it is preferable that the sea component be included in an amount of 60 weight% or less, or 50 weight% or less, or 40 weight% or less.

[0123] In the cross-section of the above-mentioned sea-island type fiber, the second polymer, which is the sea component, is arranged in such a way that it is separated from one another by 10 or more, or 10 to 20 ultrafine fibers. Here, after the sea component is leached out, it is preferable for the fineness of the ultrafine fibers to be 0.3 denier or less to enhance tactile sensation, and it is preferable for the fineness to be 0.001 denier or more to ensure colorfastness and mechanical properties.

[0124] As a non-limiting example, the ultrafine fibers included in the upper nonwoven fabric may have a fineness of 0.10 to 0.20 denier, or 0.11 to 0.20 denier, or 0.13 to 0.20 denier. In addition, the ultrafine fibers included in the lower nonwoven fabric may have a fineness of 0.15 to 0.25 denier, or 0.15 to 0.22 denier, or 0.15 to 0.20 denier.

[0125]

[0126] According to one embodiment, the upper nonwoven fabric and the lower nonwoven fabric may each have a thickness of 1.0 to 5.0 mm, 1.5 to 5.0 mm, or 1.5 to 4.0 mm, or 1.8 to 3.5 mm.

[0127] In order to ensure that the above nonwoven laminate has an appropriate level of mechanical properties, it is preferable that the upper nonwoven fabric and the lower nonwoven fabric each have a thickness of 1.0 mm or more, or 1.5 mm or more, or 1.8 mm or more. However, if the above nonwoven laminate becomes too thick, the flexibility and tactile properties of the artificial leather may deteriorate. Therefore, it is preferable that the upper nonwoven fabric and the lower nonwoven fabric each have a thickness of 5.0 mm or less, or 4.0 mm or less, or 3.5 mm or less.

[0128] In addition, the thickness ratio of the upper nonwoven fabric and the lower nonwoven fabric may be 1:0.8 to 1:1.2, or 1:0.9 to 1:1.2, or 1:0.9 to 1:1.1, which may be advantageous for the manifestation of the aforementioned effects.

[0129] Here, the thickness of the upper nonwoven fabric refers to the thickness excluding the surface nap portion formed on one side of the upper nonwoven fabric.

[0130]

[0131] According to one embodiment, the nonwoven laminate comprising the upper nonwoven fabric and the lower nonwoven fabric has a g / cm³ of 0.200 to 0.240 g / cm³ 3 , or 0.210 to 0.240 g / cm³ 3 , or 0.210 to 0.230 g / cm³ 3 It can have an apparent density.

[0132]

[0133] According to one embodiment, the nonwoven laminate may comprise 15 to 35 weight%, or 20 to 35 weight%, or 20 to 30 weight% of the polymer elastomer based on the weight of the nonwoven laminate.

[0134] In order to secure the mechanical properties of the artificial leather, it is preferable that the above nonwoven laminate be provided with 15 weight percent or more or 20 weight percent or more of the polymer elastomer. However, if the amount of the polymer elastomer provided is excessive, the texture of the artificial leather may become stiff, the nap may be reduced, or an excessive amount of the polymer elastomer may be exposed between the surface nap of the upper nonwoven fabric. Therefore, it is preferable that the above nonwoven laminate be provided with 35 weight percent or less or 30 weight percent or less of the polymer elastomer.

[0135]

[0136] Meanwhile, the artificial leather comprises a thermoplastic resin coating layer laminated on the other side of the nonwoven fabric laminate.

[0137] Here, the other side of the nonwoven laminate refers to the side opposite to the side in the nonwoven laminate where the surface nap is formed. For example, in the nonwoven laminate formed by interlacing the upper nonwoven fabric and the lower nonwoven fabric, the thermoplastic resin coating layer is laminated on the back side (rear surface) of the lower nonwoven fabric.

[0138] According to one embodiment, the thermoplastic resin coating layer is preferably formed by applying a solvent-free thermoplastic resin. Since the solvent-free thermoplastic resin can be produced without waste or residue and is recyclable, a sustainable manufacturing process can be established. Furthermore, since the solvent-free thermoplastic resin is manufactured without using organic solvents, it can comply with standards regarding volatile organic compounds (VOCs), thereby simplifying the manufacturing process of artificial leather and shortening the process time.

[0139] In particular, the artificial leather described above utilizes an environmentally friendly water-dispersible polyurethane as the polymer elastomer and includes a thermoplastic resin coating layer formed by applying a solvent-free thermoplastic resin, thereby possessing excellent mechanical properties and enabling the artificial leather to be reused and recycled without separating it layer by layer after its lifespan.

[0140] The above solvent-free thermoplastic resin may be a solvent-free polyurethane resin formed from the reaction product of an isocyanate component and a polyol component.

[0141] The above isocyanate component includes polyisocyanate. As the polyisocyanate, tolylene diisocyanate (TDI), or diphenylmethane diisocyanate (MDI), a mixture of diphenylmethane diisocyanate and polyphenylene polymethylene polyisocyanate (polymerizable MDI), or diphenylmethane diisocyanate (monomerical MDI) may be used. The above polyol component includes polyether polyol and / or polyester polyol.

[0142] Commercially available products may be used as the solvent-free thermoplastic resin mentioned above. For example, the HAPTEX series manufactured by BASF may be used as the solvent-free thermoplastic resin mentioned above.

[0143]

[0144] According to one embodiment, the thermoplastic resin coating layer may have a thickness of 0.01 mm to 20 mm, or 0.05 mm to 20 mm, or 0.05 mm to 15 mm, or 0.1 mm to 15 mm, or 0.1 mm to 10 mm, or 0.1 mm to 5 mm.

[0145] In order to ensure high elasticity and improved mechanical properties in the artificial leather, it is preferable that the thermoplastic resin coating layer has a thickness of 0.01 mm or more, or 0.05 mm or more, or 0.1 mm or more. However, if the thermoplastic resin coating layer is too thick, the flexibility and tactile properties of the artificial leather may deteriorate. Therefore, it is preferable that the thermoplastic resin coating layer has a thickness of 20 mm or less, or 15 mm or less, or 10 mm or less, or 5 mm or less.

[0146]

[0147]

[0148] According to another embodiment of the invention,

[0149] A step of providing an upper nonwoven fabric and a lower nonwoven fabric manufactured from sea-island type fibers,

[0150] A step of obtaining a nonwoven fabric laminate by interlacing the upper nonwoven fabric and the lower nonwoven fabric.

[0151] A step of obtaining a shrinkable fabric by heat-shrinking the above nonwoven fabric laminate,

[0152] A step of obtaining an impregnated cloth by immersing the shrink cloth in a solution containing a polymer elastomer,

[0153] A step of extracting sea components from the above sea-island type fiber,

[0154] A step of forming nap by grinding the surface of the upper nonwoven fabric, and

[0155] The method includes the step of forming a thermoplastic resin coating layer by applying a solvent-free thermoplastic resin to the back surface of the above-mentioned nonwoven fabric;

[0156] The above-mentioned lower nonwoven fabric has a lower apparent density than the above-mentioned upper nonwoven fabric, and

[0157] The above lower nonwoven fabric is impregnated with the above polymer elastomer at a higher weight ratio than the above upper nonwoven fabric,

[0158] A method for manufacturing the above artificial leather is provided.

[0159]

[0160] According to one embodiment, the step of providing an upper nonwoven fabric and a lower nonwoven fabric made of sea-island type fibers is performed.

[0161] The above-mentioned sea-island type fiber is a fiber having the sea component and island component described above, and can be manufactured through a conventional composite spinning method in the technical field to which the present invention belongs. Furthermore, the above-mentioned upper nonwoven fabric and the above-mentioned lower nonwoven fabric can be manufactured using the above-mentioned sea-island type fiber by a conventional method.

[0162] For example, a tow is formed by bundling sea-island type fibers produced through composite spinning, and the tow is stretched 2 to 5 times. Subsequently, 5 to 20 crimps per inch are formed on the stretched tow, and the tow is heat-set by heating to a temperature of 30 to 150°C. The heat-set tow is cut to produce sea-island type staple fibers having a length of 5 to 100 mm. Opening, blending, and carding processes are performed to uniformly blend the sea-island type staple fibers to produce a web. The obtained webs are laminated by a cross-lapping process, and the sea-island type staple fibers are entangled by needle punching, and the laminated webs are bonded together to produce the upper nonwoven fabric and the lower nonwoven fabric, respectively.

[0163] Here, the upper nonwoven fabric and the lower nonwoven fabric are provided to satisfy the previously described characteristics (apparent density, sea-island type fiber composition, fiber fineness, thickness, etc.).

[0164] Preferably, in the needle punching process for the web, by adjusting processing conditions such as the penetration density of the needles expressed in PPSC (punch per square centimeter), the stroke per minute of the needles, and the depth of the needles, an upper nonwoven fabric and a lower nonwoven fabric satisfying the above characteristics can be provided.

[0165] For example, for a web for forming the upper surface nonwoven fabric, needle punching processing may be performed with a needle penetration density of 2500 to 2700 PPSC or 2550 to 2650 PPSC; a needle stroke per minute of 380 to 420 RPM or 390 to 410 RPM; and a needle depth of 5.5 to 6.5 mm or 6.0 to 6.5 mm.

[0166] As another example, for the web for forming the above-mentioned nonwoven fabric, needle punching processing may be performed with a needle penetration density of 2300 to 2450 PPSC or 2350 to 2400 PPSC; a needle stroke per minute of 350 to 380 RPM or 360 to 380 RPM; and a needle depth of 4.5 to 5.5 mm or 5.0 to 5.5 mm.

[0167]

[0168] Next, a step of obtaining a nonwoven laminate by interlacing the upper nonwoven fabric and the lower nonwoven fabric is performed.

[0169] According to one embodiment, the upper nonwoven fabric and the lower nonwoven fabric can be sequentially laminated and needle-punched to form a nonwoven fabric laminate in which the upper nonwoven fabric and the lower nonwoven fabric are intertwined.

[0170] As a non-limiting example, when performing the needle punching, the upper and lower nonwoven fabrics can be entangled using only down strokes without up strokes. By performing needle punching using only down strokes, only the island-shaped staple fibers of the upper nonwoven fabric can penetrate into the lower nonwoven fabric, and the island-shaped staple fibers of the lower nonwoven fabric can be prevented from penetrating into the upper nonwoven fabric.

[0171]

[0172] Next, a step of heat-shrinking the above nonwoven laminate to obtain a shrink cloth is performed.

[0173] The above nonwoven laminate has its density improved by thermal shrinkage, and accordingly, the surface fiber density of the artificial leather final product increases, thereby providing excellent appearance quality and a rich nap.

[0174] According to one embodiment, the step of obtaining the shrinkage cloth is performed by heat-treating the nonwoven laminate under a steam temperature of 90°C to 120°C. For example, the shrinkage cloth can be obtained by passing the nonwoven laminate through steam or hot water for at least one minute.

[0175]

[0176] Next, a step of obtaining an impregnated cloth by immersing the shrink cloth in a solution containing a polymer elastomer is performed.

[0177] The solution containing the polymer elastomer (hereinafter referred to as the polymer elastomer solution) is preferably a water-dispersible polyurethane. The water-dispersible polyurethane refers to a water-based urethane resin dispersed in water. Pigments, light stabilizers, antioxidants, flame retardants, softeners, colorants, etc., may be additionally added to the polymer elastomer solution.

[0178] The above polyurethane is a polymer compound having urethane bonds in its molecules, and can generally be formed by the reaction of a diisocyanate compound and a polyol.

[0179] The above water-dispersible polyurethane may include one or more polyurethanes selected from the group consisting of polycarbonate-based urethane, polyester-based urethane, polyacrylic-based urethane, polytetramethylene-based urethane, polycaprolactone-based urethane, polypropylene-based urethane, and polyethylene-based urethane.

[0180] According to one embodiment, the polyurethane included in the water-dispersible polyurethane may have a weight average molecular weight (Mw) of 250,000 to 350,000 g / mol. When the weight average molecular weight range of the polyurethane is satisfied, adhesion, wear resistance, and elasticity can be secured through the use of the water-dispersible polyurethane.

[0181] As long as the above weight average molecular weight is satisfied, the method of manufacturing the water-dispersible polyurethane is not particularly limited. For example, the water-dispersible polyurethane can be obtained by neutralizing a prepolymer having units derived from polyester polyol, diol, and diisocyanate with a neutralizing agent and then stirring with distilled water.

[0182] Commercially available products may be used as the above-mentioned water-dispersible polyurethane. For example, the above-mentioned water-dispersible polyurethane may include the EVAFANOL series and NEOSTECKER series manufactured by NICCA CHEMICAL, the HYDRAN series manufactured by DIC, or the SUPERFLEX series manufactured by DKS Co. Ltd.

[0183]

[0184] Before immersing the above shrinkage cloth in a polymer elastomer solution, the shape of the shrinkage cloth can be stabilized by padding it with an aqueous polyvinyl alcohol solution, etc.

[0185] For example, the shrinkage cloth can be immersed for 0.5 to 15 minutes in a polymer elastomer solution having a solid content of 5 to 30 weight% or 10 to 25 weight% while maintaining the temperature at 10 to 30 ℃.

[0186] The impregnated fabric can be obtained by immersing the shrinkage fabric in the above polymer elastomer solution, then solidifying the hydrophilic polyurethane through a steam process and drying it.

[0187] In addition, the impregnated fabric can be heat-calendered to properly rearrange the polymer elastomer and to ensure that the short fibers on the surface of the upper nonwoven fabric are uniformly aligned.

[0188] As the upper nonwoven fabric and the lower nonwoven fabric satisfying the previously described characteristics (apparent density, sea-island fiber composition, fiber fineness, thickness, etc.) are applied, the polymer elastomer is impregnated onto the lower nonwoven fabric in the impregnated fabric at a higher weight ratio than that of the upper nonwoven fabric. That is, in the impregnation step, the polymer elastomer is impregnated onto the shrink fabric to have a weight gradient from the upper nonwoven fabric toward the lower nonwoven fabric. At this time, no special measures are required to form the weight gradient of the polymer elastomer, and it can naturally occur on the upper nonwoven fabric and the lower nonwoven fabric satisfying the above characteristics.

[0189]

[0190] According to one embodiment, the impregnated fabric preferably comprises 15 to 35 weight%, 20 to 35 weight%, or 20 to 30 weight% of the polymer elastomer based on the weight of the impregnated fabric. To ensure mechanical properties of the artificial leather, it is preferable that the impregnated fabric be provided with 15 weight% or more or 20 weight% or more of the polymer elastomer. However, if the amount of the polymer elastomer provided is excessive, the texture of the artificial leather may become stiff, the nap may be reduced, or an excessive amount of the polymer elastomer may be exposed between the surface nap of the upper nonwoven fabric. Therefore, it is preferable that the impregnated fabric be provided with 35 weight% or less or 30 weight% or less of the polymer elastomer.

[0191]

[0192] Next, a step of extracting sea components from the above-mentioned sea-island type fiber is performed.

[0193] For example, an alkaline aqueous solution is used to leach and remove seawater components from the sea-island type fibers contained in the nonwoven laminate of the impregnated fabric.

[0194] According to one embodiment, the alkaline aqueous solution may be an aqueous solution containing an alkaline compound at a concentration of 0.5 to 10% (w / w). As an example, the step may be performed using an alkaline aqueous solution with a concentration of 5 wt% NaOH.

[0195] Optionally, the step of eluting the above sea component may be performed before the process of immersing the shrinkage cloth in a polymer elastomer solution.

[0196]

[0197] Next, a step of forming nap is performed by grinding the surface of the upper nonwoven fabric.

[0198] The above process is a process of generating a large amount of napps on the surface by frictionally rubbing the surface of the upper nonwoven fabric with an appropriate abrasive means.

[0199] The above grinding can be performed by a conventional method using sandpaper. For example, the surface of the impregnated fabric (the surface of the upper nonwoven fabric) can be ground with sandpaper of #80 to #240 mesh to obtain artificial leather with nap of an appropriate length.

[0200]

[0201] Next, a step of forming a thermoplastic resin coating layer is performed by applying a solvent-free thermoplastic resin to the back surface of the above-mentioned nonwoven fabric.

[0202] The above solvent-free thermoplastic resin may be a solvent-free polyurethane resin formed from the reaction product of an isocyanate component and a polyol component.

[0203] The above isocyanate component includes polyisocyanate. As the polyisocyanate, tolylene diisocyanate (TDI), or diphenylmethane diisocyanate (MDI), a mixture of diphenylmethane diisocyanate and polyphenylene polymethylene polyisocyanate (polymerizable MDI), or diphenylmethane diisocyanate (monomerical MDI) may be used.

[0204] The above polyol component includes polyether polyols and / or polyester polyols.

[0205] Commercially available products may be used as the solvent-free thermoplastic resin mentioned above. For example, the HAPTEX series manufactured by BASF may be used as the solvent-free thermoplastic resin mentioned above.

[0206] The above thermoplastic resin coating layer can be formed by a conventional coating method. For example, the thermoplastic resin coating layer can be formed by spray coating or knife coating the solvent-free thermoplastic resin on the back surface of the bottom nonwoven fabric. For another example, the solvent-free thermoplastic resin can be applied to a release film to form a thermoplastic resin coating layer, and this can be laminated with the substrate layer so that the thermoplastic resin coating layer is laminated on the back surface of the bottom nonwoven fabric.

[0207] According to one embodiment, the thermoplastic resin coating layer may have a thickness of 0.01 mm to 20 mm, or 0.05 mm to 20 mm, or 0.05 mm to 15 mm, or 0.1 mm to 15 mm, or 0.1 mm to 10 mm, or 0.1 mm to 5 mm.

[0208] Optionally, the step of forming the thermoplastic resin coating layer may be performed before the step of forming the nap.

[0209]

[0210] If necessary, a step of dyeing the napped portion or artificial leather may be further performed.

[0211]

[0212] The artificial leather obtained by the above manufacturing method satisfies the aforementioned characteristics, thereby minimizing the exposure of the polymer elastomer between the surface nap of the upper nonwoven fabric, and while possessing excellent mechanical properties, it is possible to impart a rich nap texture and uniform color to the surface of the artificial leather. Furthermore, the artificial leather can possess excellent mechanical properties and be environmentally friendly by being easy to recycle.

[0213]

[0214] For example, artificial leather according to the above manufacturing method has a g / cm³ of 0.250 to 0.300 g / cm³ according to Formula 1 below. 3 , or 0.260 to 0.290 g / cm³ 3 , or 0.270 to 0.285 g / cm³ 3 It can represent the fiber density of.

[0215] [Equation 1]

[0216] *Fiber density (g / cm³) 3 ) = (Apparent density of nonwoven laminate) X (Weight ratio of fiber portion of artificial leather)

[0217] Apparent density of nonwoven laminate (g / cm³) 3 ) = Average unit weight of nonwoven fabric laminate (g / m²) 2 ) / Average thickness of nonwoven laminate (mm)] / 1000

[0218] * Weight ratio of fiber portion of artificial leather = (Weight after extraction of polymer elastomer from artificial leather (g)) / (Weight of artificial leather (g))

[0219] Here, the 'weight after extraction of polymer elastomer from artificial leather' is measured by immersing artificial leather in N,N-dimethylformamide at room temperature for 12 hours or more to extract the polymer elastomer, followed by washing and drying.

[0220]

[0221] As another example, the artificial leather according to the above manufacturing method may exhibit a longitudinal tensile strength of 5.0 to 7.0 kgf, or 5.2 to 6.7 kgf, or 5.5 to 6.5 kgf; and a widthwise tensile strength of 3.0 to 6.0 kgf, or 3.5 to 5.5 kgf, or 4.0 to 5.0 kgf.

[0222] As another example, the artificial leather according to the above manufacturing method may exhibit a longitudinal tensile elongation of 65 to 90%, or 70 to 85%, or 72 to 85%; and a transverse tensile strength of 100 to 125%, or 105 to 120%, or 110 to 120%.

[0223] As another example, the artificial leather obtained from the above manufacturing method may exhibit a longitudinal tear strength of 4.0 to 7.0 kgf, or 4.5 to 6.0 kgf, or 5.0 to 6.0 kgf according to the standard test method of ASTM D2261-13 (2017); and a widthwise tear strength of 4.5 to 6.5 kgf, or 5.0 to 6.0 kgf, or 5.0 to 5.5 kgf.

[0224]

[0225] Preferred embodiments are presented below to aid in understanding the invention. However, the following embodiments are merely illustrative of the invention and do not limit the invention to these embodiments.

[0226]

[0227] Example 1

[0228] Polyethylene terephthalate was used as the main component, and a copolymerized polyester was prepared as the main component in which 5 mol% of metal sulfonate-containing polyester units were copolymerized with the main component, polyethylene terephthalate.

[0229] A sea-type filament 1A (a sea-type fiber containing 16 strands of island component fibers) having a fineness of 3.5 denier was obtained by composite spinning such that the sea component and the island component have a weight ratio of 30:70. Separately, a sea-type filament 1B (a sea-type fiber containing 16 strands of island component fibers) having a fineness of 4.5 denier was obtained by composite spinning such that the sea component and the island component have a weight ratio of 30:70.

[0230] The above-mentioned sea-island type 1A filament was crimped to a crimp count of 13 per inch, heat-set, and then cut to 51 mm. A multilayer web was formed from the cut staple fibers through carding and cross-lapping processes. Subsequently, the web was needle-punched with a penetration density of 2600 PPSC, a needle stroke of 400 RPM, and a needle depth of 6 mm to obtain a fiber of 0.225 g / cm³. 3 A top surface nonwoven fabric was manufactured having an apparent density and a thickness of 2.3 mm.

[0231] The above-mentioned sea-island type 1B filament was crimped to a crimp count of 12 per inch, heat-set, and then cut to 51 mm. A multilayer web was formed from the cut staple fibers through carding and cross-lapping processes. Subsequently, the web was needle-punched with a penetration density of 2400 PPSC, a needle stroke of 370 RPM, and a needle depth of 5 mm to obtain a fiber of 0.185 g / cm³. 3 A nonwoven fabric with an apparent density and a thickness of 2.3 mm was manufactured.

[0232] A nonwoven laminate in which the upper nonwoven fabric and the lower nonwoven fabric are entangled by sequentially laminating the upper nonwoven fabric and the lower nonwoven fabric and needle punching it (apparent density 0.220 g / cm³) 3 formed ).

[0233] A shrinkage cloth was obtained by passing the above nonwoven laminate through a steam temperature of 105°C for at least 1 minute.

[0234] The above shrinkage cloth was immersed in a water-dispersible polyurethane (AE-1500, manufactured by NICCA CHEMICAL) having a solid content of 10 wt%, and then the polyurethane was solidified through a steam process and dried to obtain an impregnated cloth. At this time, the impregnated cloth was made to contain 25 wt% of polyurethane solid content based on the weight of the impregnated cloth.

[0235] The above-mentioned impregnated fabric was immersed in an aqueous NaOH solution with a concentration of 5 wt% to elute the copolymer polyester, which is the sea component, and to ultrafine it so that only the polyethylene terephthalate, which is the main component, remained. Through the above ultrafine process, ultrafine fibers with a fineness of 0.153 denier were formed in the upper nonwoven fabric portion, and ultrafine fibers with a fineness of 0.197 denier were formed in the lower nonwoven fabric portion.

[0236] The microfiber-impregnated fabric was dried, and the surface of the upper nonwoven fabric side was ground with #150 mesh sandpaper to form a nap. The impregnated fabric with the formed surface nap was dyed using a disperse dye in a high-pressure rapid dyeing machine and washed to obtain a base layer.

[0237] A solvent-free thermoplastic resin (HAPTEX, manufactured by BASF) was knife-coated onto a release film to form a thermoplastic resin coating layer with a thickness of 2 mm. This was laminated with the substrate layer and cured and dried under heat so that the thermoplastic resin coating layer was laminated onto the back surface of the lower nonwoven fabric.

[0238]

[0239] Example 2

[0240] Polyethylene terephthalate was used as the main component, and a copolymerized polyester was prepared as the main component in which 5 mol% of metal sulfonate-containing polyester units were copolymerized with the main component, polyethylene terephthalate.

[0241] A sea-type 2A filament (a sea-type fiber containing 16 strands of island-type fibers) having a fineness of 3.5 denier was obtained by composite spinning such that the sea component and the island component have a weight ratio of 30:70.

[0242] The above-mentioned sea-island type 2A filament was crimped to a crimp count of 13 per inch, heat-set, and then cut to 51 mm. A multilayer web was formed from the cut staple fibers through carding and cross-lapping processes. Subsequently, the web was needle-punched with a penetration density of 2600 PPSC, a needle stroke of 400 RPM, and a needle depth of 6 mm to obtain a fiber of 0.225 g / cm³. 3 A top surface nonwoven fabric was manufactured having an apparent density and a thickness of 2.3 mm.

[0243] Separately, the above-mentioned sea-island type 2A filament was crimped to a crimp count of 13 per inch, heat-set, and then cut to 51 mm. A multilayer web was formed from the cut staple fibers through carding and cross-lapping processes. Subsequently, the web was needle-punched with a penetration density of 2400 PPSC, a needle stroke of 370 RPM, and a needle depth of 5 mm to obtain a fiber of 0.185 g / cm³. 3 A nonwoven fabric with an apparent density and a thickness of 2.3 mm was manufactured.

[0244] A nonwoven laminate in which the upper nonwoven fabric and the lower nonwoven fabric are entangled by sequentially laminating the upper nonwoven fabric and the lower nonwoven fabric and needle punching it (apparent density 0.220 g / cm³) 3 formed ).

[0245] A shrinkage cloth was obtained by passing the above nonwoven laminate through a steam temperature of 105°C for at least 1 minute.

[0246] The above shrinkage cloth was immersed in a water-dispersible polyurethane (AE-1500, manufactured by NICCA CHEMICAL) having a solid content of 10 wt%, and then the polyurethane was solidified through a steam process and dried to obtain an impregnated cloth. At this time, the impregnated cloth was made to contain 25 wt% of polyurethane solid content based on the weight of the impregnated cloth.

[0247] The above-mentioned impregnated fabric was immersed in an aqueous NaOH solution with a concentration of 5 wt% to elute the copolymer polyester, which is the sea component, and to ultrafine it so that only the polyethylene terephthalate, which is the main component, remained. Through the above ultrafine process, ultrafine fibers with a fineness of 0.153 denier were formed on the upper and lower nonwoven fabric portions, respectively.

[0248] The microfiber-impregnated fabric was dried, and the surface of the upper nonwoven fabric side was ground with #150 mesh sandpaper to form a nap. The impregnated fabric with the formed surface nap was dyed using a disperse dye in a high-pressure rapid dyeing machine and washed to obtain a base layer.

[0249] A solvent-free thermoplastic resin (HAPTEX, manufactured by BASF) was knife-coated onto a release film to form a thermoplastic resin coating layer with a thickness of 1 mm. This was laminated with the substrate layer and cured and dried under heat so that the thermoplastic resin coating layer was laminated onto the back surface of the lower nonwoven fabric.

[0250]

[0251] Example 3

[0252] Polyethylene terephthalate was used as the main component, and a copolymerized polyester was prepared as the main component in which 5 mol% of metal sulfonate-containing polyester units were copolymerized with the main component, polyethylene terephthalate.

[0253] A sea-type 3A filament (a sea-type fiber containing 16 strands of island component fibers) having a fineness of 3.0 denier was obtained by composite spinning such that the sea component and the island component have a weight ratio of 30:70. Separately, a sea-type 3B filament (a sea-type fiber containing 16 strands of island component fibers) having a fineness of 3.5 denier was obtained by composite spinning such that the sea component and the island component have a weight ratio of 30:70.

[0254] The above-mentioned sea-island type 3A filament was crimped to a crimp count of 14 per inch, heat-set, and then cut to 51 mm. A multilayer web was formed from the cut staple fibers through carding and cross-lapping processes. Subsequently, the web was needle-punched with a penetration density of 2600 PPSC, a needle stroke of 400 RPM, and a needle depth of 6 mm to obtain a fiber of 0.225 g / cm³. 3 A top surface nonwoven fabric was manufactured having an apparent density and a thickness of 2.3 mm.

[0255] The above-mentioned sea-island type 3B filament was crimped to a crimp count of 13 per inch, heat-set, and then cut to 51 mm. A multilayer web was formed from the cut staple fibers through carding and cross-lapping processes. Subsequently, the web was needle-punched with a penetration density of 2400 PPSC, a needle stroke of 370 RPM, and a needle depth of 5 mm to obtain a fiber of 0.185 g / cm³. 3 A nonwoven fabric with an apparent density and a thickness of 2.3 mm was manufactured.

[0256] A nonwoven laminate in which the upper nonwoven fabric and the lower nonwoven fabric are entangled by sequentially laminating the upper nonwoven fabric and the lower nonwoven fabric and needle punching it (apparent density 0.220 g / cm³) 3 formed ).

[0257] A shrinkage cloth was obtained by passing the above nonwoven laminate through a steam temperature of 105°C for at least 1 minute.

[0258] The above shrinkage cloth was immersed in a water-dispersible polyurethane (AE-1500, manufactured by NICCA CHEMICAL) having a solid content of 10 wt%, and then the polyurethane was solidified through a steam process and dried to obtain an impregnated cloth. At this time, the impregnated cloth was made to contain 25 wt% of polyurethane solid content based on the weight of the impregnated cloth.

[0259] The above-mentioned impregnated fabric was immersed in an aqueous NaOH solution with a concentration of 5 wt% to elute the copolymer polyester, which is the sea component, and to ultrafine it so that only the polyethylene terephthalate, which is the main component, remained. Through the above ultrafine process, ultrafine fibers with a fineness of 0.131 denier were formed in the upper nonwoven fabric portion, and ultrafine fibers with a fineness of 0.153 denier were formed in the lower nonwoven fabric portion.

[0260] The microfiber-impregnated fabric was dried, and the surface of the upper nonwoven fabric side was ground with #150 mesh sandpaper to form a nap. The impregnated fabric with the formed surface nap was dyed using a disperse dye in a high-pressure rapid dyeing machine and washed to obtain a base layer.

[0261] A solvent-free thermoplastic resin (HAPTEX, manufactured by BASF) was knife-coated onto a release film to form a thermoplastic resin coating layer with a thickness of 1.5 mm. This was laminated with the substrate layer and cured and dried under heat so that the thermoplastic resin coating layer was laminated onto the back surface of the lower nonwoven fabric.

[0262]

[0263] Comparative Example 1

[0264] Polyethylene terephthalate was used as the main component, and a copolymerized polyester was prepared as the main component in which 5 mol% of metal sulfonate-containing polyester units were copolymerized with the main component, polyethylene terephthalate.

[0265] A sea-type 4A filament (a sea-type fiber containing 16 strands of island-type fibers) having a fineness of 3.5 denier was obtained by composite spinning such that the sea component and the island component have a weight ratio of 30:70.

[0266] The above-mentioned sea-island type 4A filament was crimped to a crimp count of 13 per inch, heat-set, and then cut to 51 mm. A multilayer web was formed from the cut staple fibers through carding and cross-lapping processes. Subsequently, the web was needle-punched with a penetration density of 2600 PPSC, a needle stroke of 400 RPM, and a needle depth of 7 mm to obtain a fiber of 0.225 g / cm³. 3 A nonwoven fabric with an apparent density and a thickness of 4.6 mm was manufactured.

[0267] A shrinkage cloth was obtained by passing the above nonwoven fabric through steam at a temperature of 105°C for at least 1 minute.

[0268] The above shrinkage cloth was immersed in a water-dispersible polyurethane (AE-1500, manufactured by NICCA CHEMICAL) having a solid content of 10 wt%, and then the polyurethane was solidified through a steam process and dried to obtain an impregnated cloth. At this time, the impregnated cloth was made to contain 25 wt% of polyurethane solid content based on the weight of the impregnated cloth.

[0269] The above-mentioned impregnated fabric was immersed in an aqueous NaOH solution with a concentration of 5 wt% to elute the copolymer polyester, which is the sea component, and to ultrafine it so that only the polyethylene terephthalate, which is the fiber component, remained. Through the above ultrafine process, ultrafine fibers with a fineness of 0.153 denier were formed in the nonwoven fabric portion.

[0270] The microfiber-impregnated fabric was dried, and the surface of the upper nonwoven fabric side was ground with #150 mesh sandpaper to form a nap. The impregnated fabric with the formed surface nap was dyed using a disperse dye in a high-pressure rapid dyeing machine and washed to obtain artificial leather.

[0271]

[0272] Comparative Example 2

[0273] Polyethylene terephthalate was used as the main component, and a copolymerized polyester was prepared as the main component in which 5 mol% of metal sulfonate-containing polyester units were copolymerized with the main component, polyethylene terephthalate.

[0274] A sea-type filament 6A (a sea-type fiber containing 16 strands of island component fibers) having a fineness of 4.5 denier was obtained by composite spinning such that the sea component and the island component have a weight ratio of 30:70. Separately, a sea-type filament 6B (a sea-type fiber containing 16 strands of island component fibers) having a fineness of 3.5 denier was obtained by composite spinning such that the sea component and the island component have a weight ratio of 30:70.

[0275] The above-mentioned sea-island type 6A filament was crimped to a rate of 12 crimps / inch, heat-set, and then cut to 51 mm. A multilayer web was formed from the cut staple fibers through carding and cross-lapping processes. Subsequently, the web was needle-punched with a penetration density of 2400 PPSC, a needle stroke of 370 RPM, and a needle depth of 5 mm to achieve a density of 0.185 g / cm³. 3 A top surface nonwoven fabric was manufactured having an apparent density and a thickness of 2.3 mm.

[0276] Separately, the above-mentioned sea-island type 6B filament was crimped to a crimp count of 11 per inch, heat-set, and then cut to 51 mm. A multilayer web was formed from the cut staple fibers through carding and cross-lapping processes. Subsequently, the web was needle-punched with a penetration density of 2600 PPSC, a needle stroke of 400 RPM, and a needle depth of 6 mm to obtain a density of 0.225 g / cm³ 3 A nonwoven fabric with an apparent density and a thickness of 2.3 mm was manufactured.

[0277] A nonwoven laminate in which the upper nonwoven fabric and the lower nonwoven fabric are entangled by sequentially laminating the upper nonwoven fabric and the lower nonwoven fabric and needle punching it (apparent density 0.220 g / cm³) 3 formed ).

[0278] A shrinkage cloth was obtained by passing the above nonwoven laminate through a steam temperature of 105°C for at least 1 minute.

[0279] The above shrinkage cloth was immersed in a water-dispersible polyurethane (AE-1500, manufactured by NICCA CHEMICAL) having a solid content of 10 wt%, and then the polyurethane was solidified through a steam process and dried to obtain an impregnated cloth. At this time, the impregnated cloth was made to contain 25 wt% of polyurethane solid content based on the weight of the impregnated cloth.

[0280] The above-mentioned impregnated fabric was immersed in an aqueous NaOH solution with a concentration of 5 wt% to elute the copolymer polyester, which is the sea component, and to ultrafine it so that only the polyethylene terephthalate, which is the main component, remained. Through the above ultrafine process, ultrafine fibers with a fineness of 0.197 denier were formed in the upper nonwoven fabric portion, and ultrafine fibers with a fineness of 0.153 denier were formed in the lower nonwoven fabric portion.

[0281] The microfiber-impregnated fabric was dried, and the surface of the upper nonwoven fabric side was ground with #150 mesh sandpaper to form a nap. The impregnated fabric with the formed surface nap was dyed using a disperse dye in a high-pressure rapid dyeing machine and washed to obtain artificial leather.

[0282]

[0283] Test example

[0284] (1) Analysis of the distribution of polymer elastomers

[0285] The impregnated fabric obtained in the above examples and comparative examples was divided into four equal parts in the thickness direction (i.e., the impregnated fabric was divided equally into a total of four layers, namely the first layer, second layer, third layer, and fourth layer, from the upper nonwoven fabric to the lower nonwoven fabric). For the four divided layers, the impregnation rate of the polymer elastomer (polyurethane) was calculated by the following formula.

[0286] *Polymer elastomer impregnation rate (%) = [ { (Weight of divided individual layers (g)) - (Weight after extracting polymer elastomer from the individual layers (g))} / (Weight of divided individual layers (g)) ] X 100

[0287] Here, the 'weight after extracting the polymer elastomer from the individual layers' is measured by immersing the individual layers, which are the first to fourth layers, in N,N-dimethylformamide at room temperature for 12 hours or more to extract the polymer elastomer (polyurethane), and then washing and drying.

[0288] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Impregnation Rate by Layer (%) 1st Layer 19.3 21.9 20.3 24.0 27.8 2nd Layer 22.0 23.2 22.2 24.9 28.1 3rd Layer 28.4 26.2 27.3 25.1 22.7 4th Layer 29.2 26.4 27.7 24.8 22.0 Average Impregnation Rate (%) 24.7 24.4 24.4 24.7 25.2

[0289] Referring to Table 1 above, it was confirmed that in the impregnated fabrics according to the above embodiments, the polymer elastomer is impregnated such that it has a weight gradient increasing from the upper nonwoven fabric to the lower nonwoven fabric of the nonwoven laminate. On the other hand, in the impregnated fabric according to Comparative Example 1, it was confirmed that the polymer elastomer is evenly impregnated throughout the impregnated fabric. In the impregnated fabric according to Comparative Example 2, it was confirmed that the polymer elastomer is distributed in a manner opposite to that of the embodiments.

[0290]

[0291] (2) Observation of the surface of artificial leather

[0292] The surface of the artificial leather with nap formed according to the above examples and comparative examples was observed by magnifying it 60 times with an optical microscope, and the grayscale images are shown in FIG. 1 (Example 1), FIG. 2 (Example 2), and FIG. 3 (Comparative Example 1).

[0293] In the grayscale images of the above drawings, the white areas or areas that are bright and close to white indicate parts where the polymer elastomer is exposed between the nap of the artificial leather surface.

[0294] Referring to the drawings, it was confirmed that the artificial leather according to the above embodiments had almost no polymer elastomers exposed between the nap on the surface and was imparted a rich nap texture.

[0295] On the other hand, in the artificial leather according to Comparative Example 1, many areas where the polymer elastomer was exposed between the nap on the surface were observed, and it was confirmed that the nap quality was poor. Although there is no image for Comparative Example 2, visual observation revealed that the artificial leather according to Comparative Example 2 also had a level of exposed polymer elastomer similar to that of Comparative Example 1, and it was confirmed that the nap quality was poor compared to the examples.

[0296]

[0297] (3) Apparent density of nonwoven fabric

[0298] The average thickness and average unit weight of the nonwoven fabric were measured and calculated using the following formula.

[0299] *Apparent density (g / cm³) 3 ) = [Average unit weight (g / m²) 2 ) / Average thickness (mm)] / 1000

[0300]

[0301] (4) Fiber density

[0302] The fiber density of artificial leather was calculated according to Equation 1 below.

[0303] [Equation 1]

[0304] *Fiber density (g / cm³) 3 ) = (Apparent density of nonwoven laminate) X (Weight ratio of fiber portion of artificial leather)

[0305] Apparent density of nonwoven laminate (g / cm³) 3 ) = Average unit weight of nonwoven fabric laminate (g / m²) 2 ) / Average thickness of nonwoven laminate (mm)] / 1000

[0306] * Weight ratio of fiber portion of artificial leather = (Weight after extraction of polymer elastomer from artificial leather (g)) / (Weight of artificial leather (g))

[0307] Here, the 'weight after extraction of polymer elastomer from artificial leather' is measured by immersing artificial leather in N,N-dimethylformamide at room temperature for 12 hours or more to extract the polymer elastomer (polyurethane), followed by washing and drying.

[0308]

[0309] (5) Tensile strength and tensile elongation

[0310] Prepare a test specimen with a width of 50 mm and a length of 250 mm. Clamp the upper part of the test specimen in the clamp of a tensile testing machine (Instron), and set the clamp spacing so that a primary load of 1.96 N (200 gf) is applied to the test specimen. The test specimen is tensile at a speed of 200 mm / min to measure the load (kgf) and elongation (%) at fracture. The above test is performed three times each in the longitudinal and transverse directions of the test specimen, and the tensile strength and tensile elongation are calculated using the average values.

[0311]

[0312] (6) Tear strength

[0313] Prepare a test specimen with a width of 40 mm and a length of 150 mm. In accordance with the standard test method of ASTM D2261-13 (2017), cut a portion of the test specimen in the longitudinal or transverse direction, and mount the left and right cut sections by clamping them to the upper and lower clamps of a tear strength measuring device. Spread the clamps at a speed of 200 mm / min to measure the maximum load (kgf) at which the test specimen ruptures. Perform the above test three times each in the longitudinal and transverse directions of the test specimen, and calculate the tear strength using the average value.

[0314]

[0315] (7) Sensory evaluation

[0316] A sensory evaluation of the artificial leather of the above examples and comparative examples was conducted on six artificial leather experts. The artificial leather was evaluated based on its appearance (napping length, napping uniformity) and tactile feel (surface touch, elasticity), and a score of 1 to 5 points was assigned.

[0317]

[0318] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Fiber density (g / cm²) 3 )0.28 10.28 20.28 30.28 60.28 4 Tensile Strength (kgf) Length Direction 5.8 6.2 6.4 5.8 5.7 Width Direction 4.3 4.7 4.7 4.0 4.1 Tensile Elongation (%) Length Direction 7 4 80 7 5 7 9 80 Width Direction 1 1 0 1 1 5 1 1 2 1 1 7 1 1 3 Tear Strength (kgf) Length Direction 5.4 5.6 5.5 2.3 2.4 Width Direction 5.1 5.2 5.2 2.1 2.1 Sensory Evaluation Appearance 5 5 5 22 Tactile 5 5 5 22

[0319]

[0320] Referring to the results of the above test examples, it was confirmed that the artificial leather according to the above embodiments possesses excellent mechanical properties equivalent to or greater than those of the artificial leather of the comparative examples, while having a rich nap on its surface and hardly any polymer elastomers exposed between the nap on the surface.

[0321]

[0322] Although the present invention has been described above by limited embodiments, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs.

Claims

1. A nonwoven fabric laminate having surface nap on one side and a substrate layer comprising a polymer elastomer impregnated on the nonwoven fabric laminate, and It includes a thermoplastic resin coating layer laminated on the other side of the above-mentioned nonwoven fabric laminate; The above nonwoven laminate comprises an upper nonwoven fabric having surface nap on one side, and a lower nonwoven fabric interlocked with another side on which surface nap is not formed on the upper nonwoven fabric. The above-mentioned lower nonwoven fabric has a lower apparent density than the above-mentioned upper nonwoven fabric, and The above lower nonwoven fabric is impregnated with the above polymer elastomer at a higher weight ratio than the above upper nonwoven fabric, Artificial leather.

2. In Paragraph 1, The above polymer elastomer is an artificial leather impregnated with water-dispersible polyurethane.

3. In Paragraph 1, Artificial leather in which the above thermoplastic resin coating layer is formed by applying a solvent-free thermoplastic resin.

4. In Paragraph 1, The above upper nonwoven fabric is 0.200 to 0.250 g / cm² 3 It has an apparent density, The above nonwoven fabric has a g / cm³ of 0.175 to 0.200 g / cm³ 3 having an apparent density, Artificial leather.

5. In Paragraph 1, The absolute value of the apparent density difference between the upper nonwoven fabric and the lower nonwoven fabric is 0.02 to 0.07 g / cm³ 3 Artificial leather.

6. In Paragraph 1, Artificial leather, wherein the lower nonwoven fabric comprises fibers having a fineness greater than or equal to that of the upper nonwoven fabric.

7. In Paragraph 6, The above-mentioned upper nonwoven fabric comprises fibers having a fineness of 2.5 to 3.5 denier, and The above-mentioned nonwoven fabric comprises fibers having a fineness of 3.5 to 5.5 denier, Artificial leather.

8. In Paragraph 1, The upper nonwoven fabric and the lower nonwoven fabric each include sea island type fibers, and The above sea-island type fiber comprises 10 to 60 weight% of sea components and 40 to 90 weight% of island components, Artificial leather.

9. In Paragraph 1, Artificial leather, wherein the upper nonwoven fabric and the lower nonwoven fabric each have a thickness of 1.0 to 5.0 mm.

10. In Paragraph 1, The above nonwoven fabric laminate is 0.200 to 0.240 g / cm 3 Artificial leather having a visible density.

11. In Paragraph 1, Artificial leather comprising 15 to 35 weight percent of the polymer elastomer based on the weight of the nonwoven laminate.

12. In Paragraph 1, Artificial leather, wherein the polymer elastomer is impregnated onto the nonwoven laminate to have a weight gradient that increases from the upper nonwoven fabric toward the lower nonwoven fabric.

13. A step of providing an upper nonwoven fabric and a lower nonwoven fabric manufactured from sea-island type fibers, A step of obtaining a nonwoven fabric laminate by interlacing the upper nonwoven fabric and the lower nonwoven fabric. A step of obtaining a shrinkable fabric by heat-shrinking the above nonwoven fabric laminate, A step of obtaining an impregnated cloth by immersing the shrink cloth in a solution containing a polymer elastomer, A step of extracting sea components from the above sea-island type fiber, A step of forming nap by grinding the surface of the upper nonwoven fabric, and The method includes the step of forming a thermoplastic resin coating layer by applying a solvent-free thermoplastic resin to the back surface of the above-mentioned nonwoven fabric; The above-mentioned lower nonwoven fabric has a lower apparent density than the above-mentioned upper nonwoven fabric, and The above lower nonwoven fabric is impregnated with the above polymer elastomer at a higher weight ratio than the above upper nonwoven fabric, Method for manufacturing artificial leather according to claim 1.

14. In Paragraph 13, The solution containing the above polymer elastomer is a water-dispersible polyurethane, and The above solvent-free thermoplastic resin is a solvent-free polyurethane resin formed from the reaction product of an isocyanate component and a polyol component, Method for manufacturing artificial leather.

15. In Paragraph 13, The above-mentioned upper nonwoven fabric is obtained by performing needle punching processing on a web formed of the above-mentioned sea-island type fibers with a needle penetration density of 2500 to 2700 PPSC (punch per square centimeter), a needle stroke per minute of 380 to 420 RPM, and a needle depth of 5.5 to 6.5 mm; The above-mentioned lower nonwoven fabric is obtained by performing needle punching processing on a web formed of the above-mentioned sea-island type fibers with a needle penetration density of 2300 to 2450 PPSC, a needle stroke per minute of 350 to 380 RPM, and a needle depth of 4.5 to 5.5 mm. Method for manufacturing artificial leather.

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