KR102375848B1 - Artificial leather for automotive interiors including circular knitting and the manufacturing method of the same - Google Patents

Abstract

The present invention relates to artificial leather used as a car seat cover, and more particularly, to a back layer from the lower part to the upper part; foam layer; And skin layer; in the artificial leather comprising a, the back layer is a circular knit formed by using a braided yarn having a specific thickness. It relates to an artificial leather comprising a circular knitted back layer and a manufacturing method thereof.

Description

Artificial leather including circular knitting back layer and manufacturing method thereof

The present invention relates to artificial leather used as a car seat cover, and more particularly, to a back layer from the lower part to the upper part; foam layer; And skin layer; in the artificial leather comprising a, the back layer is a circular knit formed by using a braided yarn having a specific thickness. It relates to an artificial leather comprising a circular knitted back layer and a manufacturing method thereof.

The interior of a car is recognized as a second residential space, and recently, a functional seat with excellent ventilation is required for comfortable and comfortable driving in such an interior space of a car.

On the other hand, as a material for automobile seats, artificial leather made of inexpensive polyvinylchloride (hereinafter referred to as 'PVC') or thermoplastic polyurethane (hereinafter referred to as 'TPU') is in the spotlight.

In general, the artificial leather consists of a laminated structure including a back side layer, a foaming layer and a cover layer from below. In the case of artificial leather punching, there was a problem of quality in that the yarn was released from the hole in the perforated part, so that the cut yarn was reflected in the front and back of the punched hole, or mechanical properties such as tensile strength were lowered (see Fig. 1).

In order to solve the above problems, as disclosed in Korean Patent Application Laid-Open No. 10-2017-0030244 (published on March 17, 2017), the back layer is made of warp knits or non-woven fabric and then impregnated with a polyurethane compounding solution. Therefore, even after punching, it was attempted to prevent hole penetration and secure mechanical properties such as tensile strength, but the warp knitted fabric and nonwoven fabric were too expensive and could only be applied to high-end car models.

Accordingly, there is an urgent need to develop artificial leather including a circular knitted back layer, which is inexpensive and has no hole see-through even after punching, and has excellent mechanical properties such as tensile strength.

KR 10-2017-0030244 (published on: March 17, 2017)

In order to solve the problems of the prior art as described above, the present invention provides an artificial leather including a circular knitted back layer having excellent mechanical properties such as tensile strength and the like, and a manufacturing method thereof, which is inexpensive and does not have a hole see-through phenomenon even after punching. The purpose.

In order to achieve the above object, the present invention provides an artificial leather comprising a circular knitted back layer using 5-30 number of braids.

In addition, the present invention provides a method for manufacturing artificial leather comprising the step of forming a circular knit back layer using the number 5-30 braids.

The artificial leather of the present invention has a low price by including a circular knitted back layer using 5-30 braided yarns, and there is no hole see-through even after punching, and has excellent mechanical properties such as tensile strength.

1 is a photograph showing the hole of the perforated part after punching the artificial leather including the back layer, which is a circular knit using a conventional single yarn.
Figure 2 is a photograph showing the hole of the perforated part after punching the artificial leather including the circular knit back layer of the present invention.
3 is a view showing an example of the single yarn (a) and the braided yarn (b) of the present invention.
4A is a view showing a specimen for measuring tensile strength and elongation.
Figure 4b shows the marked lines (ℓ ₁ , ℓ ₂ ) drawn on the specimen for measuring the static load elongation and residual shrinkage.
Figure 4c is a view showing a specimen for measuring the tear strength.
Figure 4d is a view schematically showing a part of the tensile tester.

Fabrics are classified into non-woven fabrics and woven fabrics according to the presence or absence of woven processes such as spinning, weaving, and knitting.

The nonwoven fabric refers to a fabric shape in which fibers are bonded to each other by chemical or mechanical action or heat treatment with appropriate moisture on the fiber aggregate without a weaving process.

The woven fabric refers to a fabric formed through a weaving process using the yarn after forming a fiber assembly with yarn.

The woven fabric may be further divided into a woven fabric and a knitted fabric according to a weaving method.

The fabric (織物) refers to a fabric in which two threads are entangled in the horizontal and vertical directions, and refers to a fabric in which a longitudinal thread, that is, a warp yarn, and a horizontal thread, that is, a weft thread, are entangled with each other. The fabric can be divided into plain weave, twill weave, and main weave depending on the manufacturing method, and the fabric has a strong structure but does not have elasticity, so workability is lowered when used for automotive interior parts There is this.

The knitted fabric (編物) refers to a fabric woven by continuously woven rings with a single thread, unlike fabrics. It can be divided into circular knits and warp knits according to the manufacturing method, and has good elasticity compared to fabrics. There is this. The circular knit means a fabric woven by spinning yarn in a weft direction, and a warp knit means a fabric woven by spinning a yarn in a warp direction.

The present invention relates to artificial leather comprising a circular knitted back layer using braids of number 5-30.

In the present invention, braided yarn (合絲, b) refers to a yarn that is twisted while combining two or more single yarns (單絲, a) (see FIG. 3(b)).

The single yarn (a) is a single yarn made by twisting fibers, and is the simplest and means a yarn capable of weaving itself (refer to FIG. 3(a)).

Specifically, the single yarn (a) may be divided into a filament yarn and a spun yarn according to the length of the fiber.

The filament yarn is a yarn consisting of fibers having an infinite length, natural fibers such as silk fibers, regenerated fibers such as rayon fibers or cupra fibers, and polyester fibers, polyolefin fibers, polyvinyl alcohol fibers, polyamide fibers, It may be a single yarn consisting of one type of fiber selected from the group consisting of synthetic fibers that are polyurethane fibers or polyvinylidene chloride fibers.

The spun yarn is a yarn made of fibers (short fibers) having a short length of about 0.5-2.5 inches, and natural fibers and the filament yarns are spun with cotton fibers, hemp fibers, wool fibers or wool fibers excluding silk fibers. It may be a single yarn in which one or two or more fibers selected from the group consisting of fibers cut to a length suitable for the following are mixed.

In the present invention, as a specific embodiment of the single yarn (a), polyester fibers and cotton fibers that can easily secure mechanical properties and flame-retardant properties, and can realize sewing performance and clean appearance are 60-70 : Single yarn blended in a weight ratio of 30-40 may be used, and more specifically, melange yarn in which at least one fiber is dyed for color implementation may be used.

The number of twists of the single yarn (a) may be 450-600tpm (turns per meter, number of twists/1m) or 500-580tpm. The number of twists in the single yarn (a) can be measured through the twist twist method according to KS K 0417 using a tester.

If it is less than the above range, the strength is lowered and the yarn is released from the hole portion of the perforated part during punching of artificial leather, and the cut yarn is reflected in the front and back of the punching hole (that is, the hole see-through phenomenon) or mechanical properties such as tensile strength may decrease, If the range is exceeded, the cost may increase, which may be undesirable, and thus the number of twists within the range may be present.

In addition, the single yarn (a) may be 20-40 counts or 20-30 counts. If it is less than the above range, the strength is lowered as the spatial density between the yarns is lowered, and the yarns are released from the hole in the perforated part when punching artificial leather, so that the cut yarns in front and behind the punching hole are reflected, or mechanical properties such as tensile strength may be reduced. In addition, when the above range is exceeded, the strength is lowered, and when artificial leather is punched, the yarn is released from the hole part of the perforated part, so the cut yarn in front and back of the punching hole is reflected, or mechanical properties such as tensile strength can be reduced. can

The braided yarn (b) of the present invention is a semi-twisted yarn by combining 2-4 or 2-3 single yarns (a), and when the number of single yarns (a) is less than the above range, the number of twists is small and artificial leather During punching, the yarn is loosened at the hole portion of the perforated part, and the cut yarn is reflected in the front and back of the punched hole, or mechanical properties such as tensile strength may decrease. can have a number.

In addition, the braiding (b) may be 5-30 times or 5-20 times. If out of the above range, the strength is lowered, and when the artificial leather is punched, the yarn is released from the hole portion of the perforated part, and the cut yarn is reflected in the front and back of the punching hole, or mechanical properties such as tensile strength may be reduced, so the number may be within the above range.

The circular knitting of the present invention described above can be impregnated with a polyurethane (Poly urethane, PU) solution to prevent the yarn from loosening during punching, and to improve the sewing workability of one section of the car seat cover.

At this time, the content of the polyurethane resin impregnated in the circular knit may be 15-55 g/m ² or 20-50 g/m ² . If it is less than the above range, the polyurethane resin cannot hold the yarn, so when punching, the yarn is released from the hole in the perforated part, and the cut yarn in front and behind the punching hole can be reflected. A phenomenon in which the polyurethane resin is melted and eluted to the outside of the back layer may occur, and thus the polyurethane resin may be impregnated within the above content range.

The back layer may have a density of 280-380 g/m ² or 300-350 g/m ² after being impregnated with a polyurethane solution. When the density of the back layer is less than the above range, the strength is lowered and the yarn is released from the hole portion of the perforated part during punching of artificial leather, so that the cut yarn is reflected in the front and back of the punched hole, or mechanical properties such as tensile strength may decrease, and the mechanical properties such as tensile strength may decrease, If it is exceeded, the cost may increase, which may be undesirable, and may have a density within the above range.

In addition, the back layer may have a thickness of 0.4-0.7 mm or 0.45-0.65 mm. When the thickness of the back layer is less than the above range, the strength is lowered, and the yarn is released from the hole in the perforated part during punching of artificial leather, and the cut yarn is reflected in the front and back of the punched hole, or mechanical properties such as tensile strength may decrease, If it is exceeded, as it is formed thicker than necessary, the cost may increase, which may be undesirable and may have the above thickness range.

On the other hand, the artificial leather of the present invention is a foam layer sequentially on the upper side of the circular knit using the braid (b) of the number 5-30; and a skin layer; may further include.

Hereinafter, each layer will be described in detail as follows.

The back layer may optionally have a coating layer formed on one surface to increase peel strength from the upper foam layer and to further prevent yarn loosening.

Specifically, the artificial leather of the present invention can be adsorbed and molded using vacuum during embossing to be described later. In this case, unlike the case of molding the emboss using a press-type roll embossing, the semi-finished product is not compressed with a large pressure. Since the resin of the foam layer cannot be impregnated into the back layer, there may be a disadvantage in that the peel strength between the back layer and the foam layer is lowered. Accordingly, the back layer of the present invention may be one in which a coating layer is formed on one surface to selectively increase the peel strength with the upper foam layer and to further prevent loosening of the yarn.

The coating layer may be formed using, for example, one coating solution selected from an acrylic adhesive, a polyurethane adhesive, and polyvinyl chloride plastisol. However, since the acrylic adhesive is hard after drying, the microhardness of artificial leather increases, which makes it not soft to the touch, and the polyurethane adhesive is relatively expensive and the material cost increases, so polyvinyl chloride plastisol can be used there is.

The micro-hardness is a local hardness for a micro-specimen such as about 0.5-1.0 mm thick, immediately after the needle is in contact with the specimen using an Asker Micro Durometer, MD-1 capa under an indentation rate of 1 mm/s, that is, the load of the needle. It means the maximum value (peak hold) when the holding time is 1s.

The polyvinyl chloride plastisol may include 70-130 parts by weight of a plasticizer and 0.5-10 parts by weight of a curing agent based on 100 parts by weight of the polyvinyl chloride resin.

Specifically, the polyvinyl chloride resin may be a mixed resin composed of 60-90% by weight of a homopolymer of vinyl chloride and 10-40% by weight of a copolymer of vinyl chloride and vinyl acetate.

The vinyl chloride homopolymer is a paste polyvinyl chloride resin prepared by emulsion polymerization, and may be included in an amount of 60-90% by weight or 65-85% by weight in the mixed resin. If it is less than the above range, the peel strength between the back layer and the foaming layer may be slightly lowered or the yarn may come loose, and if it exceeds the above range, it may be undesirable, such as odor, and may be included within the above range.

The copolymer of vinyl chloride and vinyl acetate is a resin that provides excellent adhesion to the back layer and the foam layer and prevents yarn loosening, and the content of vinyl acetate in the copolymer is 1-15% by weight or 3 -10% by weight may be included. If it is less than the above range, the peel strength between the back layer and the foaming layer may be slightly lowered or the yarn may be loosened.

In addition, the copolymer of vinyl chloride and vinyl acetate may be included in the mixed resin in an amount of 10-40% by weight or 15-35% by weight. If it is less than the above range, the peel strength of the back layer and the foaming layer may be slightly lowered or the yarn may be loosened.

The plasticizer may be at least one selected from a phthalate-based plasticizer, a terephthalate-based plasticizer, a benzoate-based plasticizer, a citrate-based plasticizer, a phosphate-based plasticizer, and an adipate-based plasticizer.

In the present invention, preferably, a terephthalate-based plasticizer that is environmentally friendly and has excellent heat resistance may be used. For example, dioctyl terephthalate may be used as the terephthalate-based plasticizer, but is not limited thereto.

The plasticizer may be included in an amount of 70-130 parts by weight or 80-120 parts by weight based on 100 parts by weight of the polyvinyl chloride resin. If it is less than the above range, the viscosity of the coating solution may increase and processability may decrease.

The curing agent may use a low-temperature curing type curing agent to increase energy efficiency and productivity, and a block isocyanate curing agent in which some or all of the isocyanate groups are blocked with a blocking agent may be used.

The blocking agent is phenol, ε-caprolactam, methyl ethyl ketone oxime, 1,2-pyrazole, diethyl malonate (diethyl) malonate), diisopropylamine, triazole, imidazole, and at least one selected from the group consisting of 3,5-dimethylpyrazole may be used. .

The block isocyanate curing agent blocks the isocyanate group so that the isocyanate group (-NCO) does not react with the hydroxyl group (-OH) or the amino group (-NH) at room temperature. This increases and the curing reaction proceeds.

The dissociation temperature of the curing agent may be 100 °C or higher or 110-130 °C.

The curing agent may be included in an amount of 0.5-10 parts by weight or 1-5 parts by weight based on 100 parts by weight of the polyvinyl chloride resin. If it is less than the above range, the peel strength between the back layer and the foaming layer may be slightly lowered due to a decrease in the degree of crosslinking. .

The coating solution may optionally further include one or more other additives selected from the group consisting of a stabilizer, a filler, a pigment, a viscosity lowering agent and a dispersant, if necessary, and the content thereof does not affect the physical properties of the coating solution. There is no limit if

The thickness of the coating layer may be, for example, 1-10㎛ or 2-5㎛. Here, the thickness of the coating layer means a thickness including the coating solution impregnated into the back layer. When the thickness of the coating layer is less than the above range, the peel strength of the back layer and the foaming layer may be slightly lowered or loose, and if it exceeds the above range, the microhardness of the artificial leather increases and the touch feeling is reduced. thickness can be coated.

foam layer

The foaming layer of the present invention is to impart soft properties and cushioning to the artificial leather, and may include 60-120 parts by weight of a plasticizer and 5-15 parts by weight of a foaming agent based on 100 parts by weight of the polyvinyl chloride resin.

Specifically, the polyvinyl chloride resin may be a straight polyvinyl chloride resin formed by suspension polymerization that can secure excellent cushioning feeling, high elongation, and excellent durability at the same time.

The degree of polymerization of the polyvinyl chloride resin may be less than 900-1300, or 950-1250. When it is less than the above range, durability is lowered, and when it exceeds the above range, the hardness of the foaming layer is increased and cushioning feeling is reduced, so that a polyvinyl chloride resin having a degree of polymerization within the above range can be used.

Optionally, in order to provide the foam layer with adhesion to the back layer and further prevent the yarns from unraveling the back layer, a copolymer of vinyl chloride and vinyl acetate is added to 100 parts by weight of the polyvinyl chloride resin in 5- It may further include 20 parts by weight or 5-15 parts by weight. If it is less than the above range, the peel strength with the back layer is somewhat lowered, and if it exceeds the above range, the raw material value increases, which is undesirable, so it may be included within the above range.

The content of vinyl acetate in the copolymer of vinyl chloride and vinyl acetate may be included in an amount of 0.5-10% by weight or 1-5% by weight.

The plasticizer may be one or more selected from the phthalate-based plasticizer, the terephthalate-based plasticizer, the trimellitate-based plasticizer, and the epoxy-based plasticizer.

The phthalate-based plasticizer is a plasticizer having very good compatibility with the polyvinyl chloride resin, for example, among dibutyl phthalate, diethylhexyl phthalate, diisononyl phthalate, dipropyl heptyl phthalate, diisodecyl phthalate, and butyl benzyl phthalate. It may be one selected type, but preferably diisodecyl phthalate, which is a low volatility plasticizer, may be used.

The terephthalate-based plasticizer is an eco-friendly plasticizer, for example, dioctyl terephthalate may be used, but is not limited thereto.

The trimellit-based plasticizer is a plasticizer having excellent volatility, oil resistance, and heat resistance, and may be, for example, one selected from triethylhexyl trimellitate, triisononyl trimellitate, and triisodecyl trimellitate, but is limited thereto. it is not going to be

The epoxy-based plasticizer is an epoxidized double bond of an unsaturated fatty acid glycerol ester with hydrogen peroxide or peracetic acid. For example, epoxidized soybean oil or epoxidized linseed oil may be used, but is not limited thereto.

The plasticizer may be used in 60-120 parts by weight, or 70-100 parts by weight based on 100 parts by weight of the polyvinyl chloride resin. If it is less than the above range, workability and ductility may be reduced, and if it exceeds the above range, bleeding of the plasticizer may occur.

The foaming agent is not particularly limited as long as it can form fine bubbles that give the necessary elasticity and thickness to the foaming layer, and for example, azodicarbonamide (ADCA, Azodicarbonamide), p,p'-oxybisbenzenesulfonyl hydra Zide (p,p'-Oxybis (benzenesulfonyl hydrazide)), p-toluenesulfonyl hydrazide (p-toluenesulfonyl hydrazide), and may be a chemical blowing agent such as sodium bicarbonate (Sodiumbicarbonate).

The foaming agent may be used in an amount of 5-15 parts by weight, or 5-10 parts by weight based on 100 parts by weight of the polyvinyl chloride resin. If it is less than the above range, the softness and cushioning feeling of the artificial leather is reduced, and if it exceeds the above range, the foaming layer is over-foamed and generated, and the surface properties and durability are reduced, so it can be used within the above range.

In addition, the foam layer may further include one or more selected from a heat stabilizer, a flame retardant, and a filler to control melt strength and physical properties, and the type and content thereof are not limited.

In addition, the foam layer may have a foaming rate of 100-500% or 150-350%. By having a foaming rate within the above range, it is possible to secure a sense of volume, cushioning, and a soft surface texture. It is preferable to have a foaming rate within the above range because the durability and strength of the artificial leather are weakened and the physical properties are lowered.

In addition, the foam cells may be included in 10-30, or 15-20 per unit area of 1 mm ² of the layer surface of the foam layer. When it is less than the above range, ductility and cushioning feeling are reduced, and when it exceeds the above range, surface durability is lowered and physical properties such as surface feel and cushioning feeling are lowered, so the number of foam cells within the above range can be included.

In addition, the foam layer may have a thickness of 0.4-0.7mm or 0.4-0.6mm after foaming, and when it is less than the above range, the cushioning feeling is reduced, and when it exceeds the above range, the material cost is high as it is formed thicker than necessary. In addition, a large number of thick wrinkles may occur, which may decrease commercial properties.

skin layer

The skin layer of the present invention is for securing surface smoothness and realizing color, and may include 60-120 parts by weight of a plasticizer and a pigment based on 100 parts by weight of the polyvinyl chloride resin.

Specifically, as the polyvinyl chloride resin included in the skin layer, a straight polyvinyl chloride resin formed by suspension polymerization may be used, and it is preferable to use a polyvinyl chloride resin having a higher degree of polymerization than the polyvinyl chloride resin used in the foaming layer. It is preferable because it can prevent the skin layer from bursting during foam molding.

The polyvinyl chloride resin included in the skin layer may have a polymerization degree of 1300-3000, or 1300-2000. If it is less than the above range, there is a risk that the skin layer may burst during foam molding, and if it exceeds the above range, the surface feel and ductility may decrease, so that a polyvinyl chloride resin having a degree of polymerization within the above range may be used.

The pigment may be carbon black, but is not limited thereto.

In addition, the skin layer may further include at least one selected from a heat stabilizer, a flame retardant, and a filler to control melt strength and physical properties.

Since the plasticizer, heat stabilizer, flame retardant and filler included in the skin layer are the same as the plasticizer, heat stabilizer, flame retardant and filler included in the above-described foam layer, the overlapping description will be omitted.

The thickness of the skin layer may be 100-300 μm, or 120-200 μm. If it is less than the above range, the surface smoothness and workability are reduced, and the material cost may increase due to an increase in the amount of pigment added to realize color. Accordingly, material cost may be high, and thus the thickness may be within the above range.

Optionally, the artificial leather of the present invention may further include a surface treatment layer on the upper part of the skin layer to improve stain resistance and simultaneously satisfy a squeak index and a dynamic friction coefficient to improve a soft touch and seating feeling. .

The surface treatment layer may be formed using an aqueous surface treatment agent containing 100 parts by weight of the main agent, 1-25 parts by weight of a curing agent, 1-25 parts by weight of an aqueous solvent and 1-15 parts by weight of a silicone compound.

The subject may be a water-dispersed polycarbonate-based polyurethane resin, but is not limited thereto.

The curing agent may include at least one functional group selected from the group consisting of an aziridine group, an isocyanate group, and a carbodiimide group per molecule.

The silicone compound may be in a liquid form in which polysiloxane is dispersed in water or polysiloxane in a bead form, but may preferably be in a liquid form in which polysiloxane is dispersed in water having better surface feel.

When the content of the silicone compound is less than the above range, the antifouling property is lowered, and when the content exceeds the above range, the surface feel is excessively slippery to minimize the squeak index, but the sitting feeling is not good because it does not satisfy the appropriate level of the coefficient of dynamic friction. It can be used within the content range.

That is, the artificial leather of the present invention can satisfy both the squeak index and the coefficient of kinetic friction by including the silicone compound in the specific range.

More specifically, the squeak index is a numerical value of noise generated in friction between artificial leather and the human body, that is, a passenger. By measuring the deviation (ΔF) and the average force (Fa) of the force required to press and pull at a speed of 100 mm/min, the squeak index can be calculated as ΔF/ Fa.

The squeak index satisfies the above range as less than 0.15, or 0.14 or less, so that the noise is low and the touch is soft. When the above range is exceeded, the squeak index may be within the above range because the stick slip characteristic, which is a friction phenomenon accompanied by severe noise and vibration, is strong.

The coefficient of dynamic friction (μ) is to hold the slip property when an object moves while slidingly in contact with another object. Using a universal testing machine, stack artificial leather specimens up and down, respectively, and press with a weight of 4.5 kg (W) to 300 mm / By measuring the average force (Fa) required to pull at the speed of min, the coefficient of kinetic friction can be measured in Fa/W.

The coefficient of kinetic friction may be 0.2-0.5 or 0.25-0.5. If it is less than the above range, it does not hold the slip property, so the sitting feeling is not good.

In addition, the aqueous surface treatment agent of the present invention may further include 0.1-0.5 parts by weight of an antifoaming agent and 1-5 parts by weight of a leveling agent for workability and physical properties, optionally from the group consisting of urethane beads, acrylic beads, and fluorinated waxes. It may further include one or more selected.

By further including at least one selected from the group consisting of the urethane beads, acrylic beads, and fluorinated waxes, antifouling properties can be implemented by hydrophobicity, and slip properties can be further provided by reducing the surface tension of the aqueous surface treatment agent. .

In addition, according to the role of the aqueous surface treatment agent, it may further include at least one selected from surfactant, cosolvent, modifier, matting agent, gloss enhancer, thickener, and matting agent, and their types and contents are not particularly limited.

The surface crosslinking density of the surface treatment layer is 70-98%, or 75-95%, and by securing the surface crosslinking density in the above range, contaminants cannot penetrate into the surface treatment agent, so that it can have excellent antifouling properties.

For the surface crosslinking density, after weighing the artificial leather specimen to 1 mg with a chemical balance (m1), place it on a container made of a mesh or a perforated metal plate, and then place the container in boiling xylene or decahydronaphthalene and leave for 6-8 hours. . After that, take out the container with the residue from the boiling solvent, cool it to room temperature, dry it, and measure the residual amount (m2) to 1 mg and calculate it as m2/m1 x 100.

In addition, the surface tension of the surface treatment layer is 90-130˚ or 95-120˚ by maintaining the surface tension in the above range, it can have an excellent antifouling property compared to the surface treatment layer formed with an oil-based surface treatment agent.

When the surface tension is spread on artificial leather using a pen (dyne pen) containing a liquid having a specific tension of 20˚-60˚, if the tension of the liquid is greater than the surface tension of the artificial leather, the liquid does not spread and the liquid does not spread. The spherical shape is maintained, and if the tension of the liquid is less than the surface tension of the artificial leather, the liquid spreads flat and spreads well. .

The surface treatment layer may have a thickness of 4-30 μm or 4-20 μm. By maintaining the thickness of the surface treatment layer within the above range, it is possible to simultaneously secure the stain resistance while maintaining the flexibility of the artificial leather. If the thickness is less than the above range, durability may be reduced because the thickness is too thin.

Also optionally, the artificial leather of the present invention may further include an embossing pattern on the skin layer and the surface treatment layer in order to give a three-dimensional effect.

The tensile strength of the artificial leather of the present invention after punching may be 15-30 kgf/30 mm in the longitudinal direction and 12-24 kgf/30 mm in the width direction, and by satisfying the above ranges, mechanical properties may be excellent even after punching.

In addition, the reduction rate of the tensile strength before and after punching of the artificial leather of the present invention may be -57% to -15% in the width direction, and by satisfying the above range, mechanical properties may be excellent even after punching.

In the present invention, the longitudinal direction means a machine direction, that is, Machine Direction (MD), and the width direction means a Transverse Direction (TD) perpendicular to the machine direction.

In addition, the elongation of the artificial leather after punching of the present invention may be 55-70% in the longitudinal direction and 150-180% in the width direction, and by satisfying the above ranges, mechanical properties may be excellent even after punching.

In addition, the increase rate of the elongation before and after punching of the artificial leather of the present invention may be 13% to 40% in the longitudinal direction, and by satisfying the above range, mechanical properties may be excellent even after punching.

In addition, the static load elongation after punching of the artificial leather of the present invention may be 15-25% in the longitudinal direction and 40-55% in the width direction, and by satisfying the above ranges, mechanical properties may be excellent even after punching.

In addition, the increase rate of the static load elongation before and after punching of the artificial leather of the present invention may be 14% to 55% in the width direction, and by satisfying the above range, mechanical properties may be excellent even after punching.

In addition, the residual shrinkage after punching of the artificial leather of the present invention may be 1.5-3.5% in the longitudinal direction and 5-9% in the width direction, and by satisfying the above ranges, mechanical properties may be excellent even after punching.

In addition, the increase rate of the residual shrinkage ratio before and after punching of the artificial leather of the present invention may be 11% to 98% in the width direction, and by satisfying the above range, mechanical properties may be excellent even after punching.

In addition, the tear strength after punching of the artificial leather of the present invention may be 3.8-5.5 kgf in the longitudinal direction and 4.0-4.7 kgf in the width direction, and by satisfying the above ranges, mechanical properties may be excellent even after punching.

In addition, the reduction rate of the tear strength before and after punching of the artificial leather of the present invention may be -32% to -3% in the longitudinal direction, -14% to -1.1% in the width direction, and by satisfying the above range even after punching Mechanical properties may be excellent.

In addition, the fracture strength after punching of the artificial leather of the present invention may be 9-15 kgf/cm ² in the longitudinal direction, and by satisfying the above range, mechanical properties may be excellent even after punching.

In addition, the peel strength after punching of the artificial leather of the present invention may be 1.8-5 kgf/30 mm in the longitudinal direction and 1.8-5 kgf/30 mm in the width direction, and by satisfying the above ranges, mechanical properties may be excellent even after punching.

In addition, the reduction rate of the peel strength before and after punching of the artificial leather of the present invention may be -72% to -30% in the longitudinal direction, and by satisfying the above range, mechanical properties may be excellent even after punching.

The tensile strength, elongation, static load elongation, residual shrinkage, tear strength, rupture strength and peel strength are 32 pieces/in ² of artificial leather in a circular pin type with a diameter of 1.0mm, at an interval of 7mm in width and 7mm in length. This is the result measured after punching in a regular pattern to have a perforation of

The artificial leather of the present invention has a low price by including a circular knitted back layer using 5-30 braided yarns, and there is no hole see-through even after punching, and has excellent mechanical properties such as tensile strength.

The present invention relates to a manufacturing method of artificial leather comprising a;

The step of forming the back layer is a step of forming a circular knit by knitting the twisted braid (b) with a circular knitting machine while combining 2-4 single yarns (a) having a twist number of 20-40 times 450-600 tpm.

In addition, the step of forming the back layer may include the step of immersing in a polyurethane solution to prevent the yarn from loosening after punching after forming the circular knit.

The PU solution may include 20-35% by weight of polyurethane resin, 55-70% by weight of dimethylformamide, and 4-7% by weight of pigment.

In addition, the step of forming the back layer may optionally further include the step of coating one surface with a coating solution in order to increase the peeling strength and to further prevent the loosening of the upper foam layer.

The viscosity of the coating solution may be 80-140 seconds or 100-120 seconds at 25° C. with a ?猪? (Zahn cup, #3 cup) viscosity. If it is less than the above range, the coating solution flows down and the coating efficiency is lowered. .

In addition, the coating solution may be applied to one surface of the back layer by a conventional coating method, and may be applied through gravure coating as a specific example, but is not limited thereto.

Then, the coating solution applied to one surface of the back layer may be gelated by applying heat at a temperature of 100-150°C.

Other properties of the coating solution are the same as those described above, so a duplicate description will be omitted.

The manufacturing method of the artificial leather of the present invention includes: i) after the step of forming the back layer, ii) forming the pre-foaming layer and the skin layer, iii) after laminating the back layer on the bottom of the pre-foaming layer, the back layer is laminated The method may further include laminating a skin layer on the pre-foaming layer, and iv) foaming the pre-foaming layer to form a foaming layer.

Hereinafter, each step will be described in detail as follows.

In step ii), the pre-foaming layer and the skin layer may be formed by kneading the pre-foaming layer and the skin layer composition, respectively, and passing them through a calender roll at 160-170°C.

The pre-foaming layer is foamed during foam molding to form a foamed layer. Since the pre-foaming layer composition is the same as the composition of the foaming layer described above, the overlapping description will be omitted. In addition, since the skin layer composition is the same as that of the skin layer described above, the overlapping description will be omitted.

In addition, in step iii) the back layer from the bottom to the top; pre-foaming layer; And when the skin layer is laminated, thermal plywood can be formed at 150-180°C.

Specifically, the reason that the back layer is thermally laminated on the bottom surface of the pre-foamed layer and then the skin layer is laminated on the pre-foamed layer on which the back layer is laminated is because the back layer has excellent mechanical strength such as tensile strength. This is because each layer holds the physical properties. If the pre-foaming layer and the skin layer are laminated first, there is a problem in that bubbles or curling occurs during thermal plywood. It may be thermal plywood.

In step iv), the back layer; pre-foaming layer; It may be a step of forming a foaming layer by passing the semi-finished product on which the skin layer is laminated through an oven at 220-240° C. to foam the pre-foaming layer.

The manufacturing method of the artificial leather of the present invention may optionally further include the step of forming a surface treatment layer by applying and drying an aqueous surface treatment agent on the skin layer of the semi-finished product that has undergone the foaming process.

Since the aqueous surface treatment agent is the same as described above, a redundant description will be omitted.

The method of applying the aqueous surface treatment agent may be a method such as gravure coating, knife coating, or bar coating, but is not limited thereto.

In addition, the drying process may evaporate the aqueous solvent by drying at 110-150° C. or 130-150° C. for 80-120 seconds.

In addition, the manufacturing method of the artificial leather of the present invention may optionally further include an embossing pattern forming step, and the embossing pattern may be formed using a compression-type roll embossing or a vacuum adsorption-type roll embossing.

In one embodiment, when the embossing pattern is formed by using the compression-type roll embossing, after the step iv) forming the foaming layer, the skin layer is softened by irradiating infrared rays to 1 using the pressing-type roll embossing. After forming the embossing pattern under a pressure of -5Mpa or 2-4Mpa, the step of forming a surface treatment layer by applying an aqueous surface treatment agent may be performed.

This is because, after forming the surface treatment layer, if the embossing pattern is formed using the press-type roll embossing, the very thin surface treatment layer may be broken by the pressure of the press-type roll embossing. It is preferable to form a surface treatment layer after forming the pattern.

In another embodiment, when the embossing pattern is formed using the vacuum adsorption roll embossing, after the step of forming the surface treatment layer, infrared rays are irradiated and heated, and then 0.02-0.08Mpa using the vacuum adsorption roll embossing. , or an emboss pattern can be formed under a vacuum pressure of 0.04-0.07Mpa.

The infrared irradiation step may be a step of irradiating infrared rays for 5-15 seconds or 10-15 seconds at 150-180 ℃. When infrared rays are irradiated at less than the above temperature and time, the skin layer is not softened and embossing is not well formed. there is.

In addition, the manufacturing method of the artificial leather of the present invention may further include the step of punching processing. In a specific embodiment, the punching process is performed while a pin is fixed to a plate-shaped supporter having a width of 160 cm and a length of 10 cm, and the artificial leather passes under the plate-shaped supporter at a speed of about 0.5-2 m/min. .

The artificial leather of the present invention may be used for automobile interior materials, specifically, it may be used for a seat cover applied to an automobile seat, and more specifically, it may be used as a side cover, a bolster, or a main cover.

The artificial leather of the present invention may be used for the main cover in a specific embodiment.

When used as the main cover, for durability, preferably, a compression-type roll embossing rather than a vacuum adsorption-type roll embossing may be used.

Hereinafter, preferred examples are presented to help the understanding of the present invention, but the following examples are merely illustrative of the present invention, and it will be apparent to those skilled in the art that various changes and modifications are possible within the scope and spirit of the present invention, It goes without saying that such variations and modifications fall within the scope of the appended claims.

[Example]

1. Artificial leather manufacturing

<Example 1>

i) The number 15 braid (b) was put into a circular knitting machine (Financial Machinery/SamS Machinery/Ssangyong Machinery) and knitted to form a circular knitting machine. At this time, the braided yarn is a twisted yarn by combining two melange yarns (a) in which polyester fibers and cotton fibers having a twist number of 30 times are 540tpm in a weight ratio of 60-70: 30-40. .

Then, by impregnating the circular knit in a polyurethane solution containing 20-35% by weight of polyurethane resin, 55-70% by weight of dimethylformamide and 4-7% by weight of pigment, the polyurethane resin is impregnated in an amount of 40 g/m ² , a circular knit back layer having a thickness of 0.5 mm with a density of 300 g/m ² was formed.

ii) 10 parts by weight of a copolymer of vinyl chloride and vinyl acetate (LC070, LG Chem) whose content of vinyl acetate is 3% by weight relative to 100 parts by weight of a straight polyvinyl chloride resin having a degree of polymerization of 1000 (LS100, LG Chem) , phthalate plasticizer ^① (DIDP, LG Chem) 80 parts by weight, epoxy plasticizer ^② (Woochang Industries) 5 parts by weight, foaming agent (ADCA) 6 parts by weight, and heat stabilizer (KBZ-270G, KDchem) 2 parts by weight Pre-foaming layer composition including parts, 100 parts by weight of straight polyvinyl chloride resin (LS130S, LG Chem) having a polymerization degree of 1300, phthalate plasticizer ^① (DIDP, LG Chem) 90 parts by weight, epoxy plasticizer ^② (Woochang Co., Ltd.) Company) 5 parts by weight, 2 parts by weight of pigment (carbon black), and 2 parts by weight of heat stabilizer (KBZ-270G) After kneading each skin layer composition, pass it through a calender roll at 160-170° C. A foam layer and a skin layer having a thickness of 150 µm were formed.

iii) Next, the circular knit back layer formed above on the bottom surface of the pre-foaming layer was thermally laminated at 150-180° C., and then the skin layer was thermally laminated at 150-180° C. .

iv) then, the back surface layer; pre-foaming layer; A back layer containing a foaming layer having a thickness of 0.6 mm from the bottom to the top by passing the semi-finished product with the skin layer laminated thereto through an oven at 220° C. and foaming the pre-foaming layer at a foaming rate of 170-250%; foam layer; A semi-finished product in which the skin layers were laminated was formed.

Thereafter, the skin layer was softened by irradiating infrared rays at 150-180° C. for 14 seconds, and then an embossing pattern was formed using a press-type roll embossing under a pressure of 1-5 Mpa.

Next, an artificial leather was prepared by gravure coating an aqueous surface treatment agent on the skin layer of the semi-finished product having the embossed pattern and forming a surface treatment layer having a thickness of 15 μm through a drying process at 140° C. for 80-120 seconds.

At this time, the water-based surface treatment agent contains 5 parts by weight of a curing agent (XR-78-017, Stahl), 5 parts by weight of a silicone compound ( 5 parts by weight of HM-13-118, Stahl Corporation), 20 parts by weight of an aqueous solvent (15 parts by weight of water and 5 parts by weight of isopropyl alcohol), 2 parts by weight of a leveling agent, and 0.2 parts by weight of an antifoaming agent.

<Comparative Example 1>

i) One single yarn (a) having a number of twists of 540tpm in number 30 was put into a circular knitting machine and knitted to form a circular knit. Then, by impregnating the circular knit in a polyurethane solution containing 20-35% by weight of polyurethane resin, 55-70% by weight of dimethylformamide and 4-7% by weight of pigment, the polyurethane resin is impregnated in an amount of 40 g/m ² , a circular knit back layer having a thickness of 0.5 mm with a density of 200 g/m ² was formed.

ii) A pre-foaming layer composition comprising 85 parts by weight of a plasticizer, 6 parts by weight of a foaming agent, and 2 parts by weight of a heat stabilizer with respect to 100 parts by weight of a straight polyvinyl chloride resin having a degree of polymerization of 1000, and 100 parts by weight of a straight polyvinyl chloride having a degree of polymerization of 1000 A skin layer composition containing 95 parts by weight of a plasticizer, 2 parts by weight of a pigment, and 2 parts by weight of a heat stabilizer was respectively kneaded and passed through a calender roll at 160-170° C. to form a pre-foamed layer with a thickness of 0.3 mm and a skin layer with a thickness of 150 μm. did.

At this time, the straight polyvinyl chloride resin, a plasticizer, a pigment, and a heat stabilizer were the same as in Example.

iii) Next, the circular knit back layer formed above on the bottom surface of the pre-foaming layer was thermally laminated at 150-180° C., and then the skin layer was thermally laminated at 150-180° C. .

iv) then, the back surface layer; pre-foaming layer; A back layer containing a foaming layer having a thickness of 0.6 mm from the bottom to the top by passing the semi-finished product with the skin layer laminated thereto through an oven at 220° C. and foaming the pre-foaming layer at a foaming rate of 170-250%; foam layer; A semi-finished product in which the skin layers were laminated was formed.

Thereafter, the skin layer was softened by irradiating infrared rays at 150-180° C. for 14 seconds, and then an embossing pattern was formed using a press-type roll embossing under a pressure of 1-5 Mpa.

Then, an oil-based surface treatment agent was gravure-coated on the skin layer of the semi-finished product having the embossed pattern, followed by a drying process at 140° C. for 80-120 seconds to form a surface treatment layer having a thickness of 15 μm, thereby manufacturing artificial leather.

In this case, the oil-based surface treatment agent includes 95% by weight of urethane acrylate, and 5% by weight of methylene dicyclohexyl diisocyanate as a curing agent.

<Reference Example 1>

An artificial leather was manufactured in the same manner as in Example 1, except that the following yarn was used as a yarn used to form the circular knit back layer.

i) The number 40 braids (b) were put into a circular knitting machine and knitted to form a circular knit. At this time, the braided yarn is a yarn that has been twisted while combining two melange yarns (a) having a twist number of 80 times 540 tpm.

Then, by impregnating the circular knit in a polyurethane solution containing 20-35% by weight of polyurethane resin, 55-70% by weight of dimethylformamide and 4-7% by weight of pigment, the polyurethane resin is impregnated in an amount of 40 g/m ² , a circular knit back layer having a thickness of 0.5 mm with a density of 250 g/m ² was formed.

<Reference Example 2>

An artificial leather was manufactured in the same manner as in Example 1, except that the following yarn was used as a yarn used to form the circular knit back layer.

i) The braid (b) having the number 3 was put into a circular knitting machine and knitted to form a circular knit. At this time, the braided yarn is a yarn that has been twisted while combining two melange yarns (a) having a twist number of 540 tpm in number 6 .

Then, by impregnating the circular knit in a polyurethane solution containing 20-35% by weight of polyurethane resin, 55-70% by weight of dimethylformamide and 4-7% by weight of pigment, the polyurethane resin is impregnated in an amount of 40 g/m ² , a circular knit back layer having a thickness of 0.5 mm with a density of 450 g/m ² was formed.

<Reference Example 3>

An artificial leather was prepared in the same manner as in Example 1, except that the circular knit was not impregnated in a separate polyurethane solution and a back layer having a density of 270 g/m ² was used.

2. Measurement of appearance and mechanical properties when punching artificial leather

The artificial leather of Example 1, Comparative Example 1, and Reference Examples 1-3 prepared in 1 was a circular pin type having a diameter of 1.0 mm, and 32 perforations/in ² were made at intervals of 7 mm in width and 7 mm in length. After punching in a regular pattern to have it, the external appearance and mechanical properties thereof were measured, and the results are shown in Table 1 below.

- For the appearance, it was visually checked whether the sand was reflected in the hole part of the perforated part.

(X: Saga cut through the front and back of the punching hole is reflected, Δ: Saga is slightly reflected, ○: Saga is not reflected)

- For mechanical properties, tensile strength, elongation, static load elongation, residual shrinkage, tear strength, burst strength and peel strength were measured.

-The tensile strength and elongation were measured using a tensile tester (Instron, Shimadzu Corporation), and according to MS 300-31, 5 specimens of Fig. 4a were taken in each of the horizontal and vertical directions, and a mark line (ℓ) was drawn 100mm, Get the maximum weight when the specimen breaks by biting it on the tester and pulling it at 200mm/min.

Elongation is calculated according to the following formula.

[Equation 1]

L= (L ₁ -L ₀ )/L ₀ X 100

(However, L: Elongation (%), L ₀ : Distance between gauge points before test, L ₁ : Distance between gauge points when skin or bubble breaks after test)

-The static load elongation and residual shrinkage ratio are the case where artificial leather is manufactured as a specimen having a width of 50 mm and a length of 250 mm, respectively, in accordance with MS 300-31, and the length direction (MD) is the width and the width direction (TD) is the width In the case of , take three each, and draw marks (ℓ ₁ , ℓ ₂ ) with a distance of 100 mm in the center of the line (see FIG. 4b ). Set this to 150mm between the clamps and leave the static load on the fatigue tester for 10 minutes to find the distance between the marks (L1). Also, remove the test piece from the clamp, remove the load, and leave it on a flat table for 10 minutes to determine the distance between the marks (L2). The static load elongation and residual shrinkage were calculated according to the following formula.

[ceremony]

Static load elongation (%) = L1 - 100

Residual shrinkage rate (%) = L2 - 100

L1 : Distance of mark 10 minutes after load is applied

L2 : Distance of the mark 10 minutes after the load is removed

-The tear strength is measured in the case where the length direction (MD) is the width and the width direction (TD) according to MS 300-31 after manufacturing artificial leather as a specimen having a width of 40 mm and a length of 150 mm (see Fig. 4c) In the case of the width of , take 5 each, bite the specimen into a clamp (see Fig. 4d) of a tensile testing machine (Instron, Shimadzu), and obtain the load when tearing to the mark line (ℓ) at 200 mm/min from the average of the maximum values.

-The rupture strength is measured using a rupture tester (MULLEN-type rupture strength tester) in accordance with MS 300-31 to prepare a specimen with a width of 100mm and a length of 100mm from the artificial leather. Mount it with the film side down and apply pressure.

Bursting strength is expressed as the pressure when the rubber diaphragm breaks through the test piece, and the result is shown with the average value of three specimens.

-The peel strength is based on MS 300-31, by preparing a specimen with a width of 30 mm and a length of 150 mm from artificial leather, taking 5 pieces each in the horizontal and vertical directions, and adding a solvent such as methyl ethyl ketone (MEK) to the foam side. After impregnation, the epidermis (foam layer) and the cells (rear layer) are forcibly peeled off by 50 mm in length parallel to the short side, taking care not to apply stress to the epidermis (foaming layer).

After peeling, leave the test piece in the room for 2 hours or more to sufficiently volatilize the solvent. The load at the time of peeling by 50 mm is obtained as the average value of the maximum values.

The test result is obtained as the average value of five specimens.

As confirmed in Table 1, Example 1, which is an artificial leather including a circular knitted back layer according to the present invention, has excellent appearance (see Fig. It was confirmed that mechanical properties such as tensile strength were also excellent even after punching.

On the other hand, unlike Example 1, Comparative Example 1, which is artificial leather including a circular knit back layer woven using single yarns, not braided yarns, has a poor appearance because the yarns cut in front and back of the punching hole are transparent after punching, Example 1 It was confirmed that mechanical properties such as tensile strength were lowered compared to that, and in particular, the values of static load elongation and residual shrinkage were too large, which was very dangerous.

In Comparative Example 1, the degree of polymerization of the polyvinyl chloride resin included in the foaming layer and the polyvinyl chloride resin included in the skin layer is the same, so the skin layer bursts during the foaming step, and the amount of VOC generated by using an oil-based surface treatment agent as a surface treatment agent There was also a disadvantage that there were many teeth and the smell was poisonous.

In addition, compared to Example 1, reference example 1, which is an artificial leather including a circular knitted back layer formed using a yarn having a thickness too thin compared to Example 1, and a yarn whose thickness is too thick compared to Example 1 Reference Example 2, which is an artificial leather including a circular knit back layer formed using , in particular, it was found that the physical property value of tensile strength was too small and the property value of residual shrinkage was too large.

In addition, Reference Example 3, which is an artificial leather containing a circular knit back layer that is not impregnated in a separate PU solution, has missing all, so the appearance is not neat, and it is known that mechanical properties such as tensile strength are lowered compared to Example 1. could

Claims (25)

A circular knitted back layer using 5-20 number of braids (合絲, b); polyvinyl chloride-based foam layer; a polyvinyl chloride-based skin layer subjected to surface softening; emboss; and a surface treatment layer; as an artificial leather comprising:
The foaming layer contains 5 to 15 parts by weight of a copolymer of vinyl chloride and vinyl acetate, and 60 to 120 parts by weight of a plasticizer, in 100 parts by weight of a polyvinyl chloride resin,
The copolymer of vinyl chloride and vinyl acetate has a vinyl acetate content of 1 to 5% by weight in a total of 100% by weight of the copolymer,
The skin layer comprises 60 to 120 parts by weight of a plasticizer and a pigment in 100 parts by weight of a polyvinyl chloride resin,
The surface treatment layer is provided from a composition comprising 1 to 25 parts by weight of a curing agent, 1 to 25 parts by weight of an aqueous solvent, and 1 to 15 parts by weight of a silicone compound to 100 parts by weight of an aqueous dispersion polycarbonate-based polyurethane resin,
The circular knit includes 15-55 g/m ^{2 of polyurethane resin and provides a back layer having a density of 280-380 g/m 2 ,}
Artificial leather, characterized in that there is no see-through after punching. The method of claim 1,
The braided yarn (b) is an artificial leather consisting of 2-4 single yarns (單絲, a). 3. The method of claim 2,
The single yarn (a) is an artificial leather that is a spun yarn (spun yarn). 4. The method of claim 3,
The single yarn (a) is an artificial leather that is a single yarn blended with polyester fiber and cotton fiber in a weight ratio of 60-70: 30-40. 5. The method of claim 4,
The single yarn (a) is a melange yarn (melange yarn) of artificial leather. 3. The method of claim 2,
The number of twists of the single yarn (a) is 450-600tpm (turns per meter, number of twists / 1m) of artificial leather. 3. The method of claim 2,
The single yarn (a) is 20-40 times artificial leather. The method of claim 1,
The surface softening treatment of the skin layer is performed by irradiating infrared rays at 150 to 180° C. for 10 to 15 seconds, so that the thickness is within the range of 120-200 um. The method of claim 1,
The back layer is made of polyurethane impregnation, and the thickness is 0.4-0.7mm artificial leather. delete The method of claim 1,
The artificial leather has a squeak index of less than 0.15, and a dynamic friction coefficient (μ) of 0.2-0.5. The artificial leather of any one of claims 1 to 9, further comprising a punching hole, wherein the tensile strength is 15-30kgf/30mm in the longitudinal direction and 12-24kgf/30mm in the width direction. The artificial leather of any one of claims 1 to 9, further comprising a punching hole, wherein the reduction in tensile strength compared to before punching is -57% to -15% in the width direction. The artificial leather of any one of claims 1 to 9, further comprising a punching hole, wherein the elongation is 55-70% in the longitudinal direction and 150-180% in the width direction. The artificial leather of any one of claims 1 to 9, further comprising a punching hole, wherein the increase rate of elongation compared to before punching is 13% to 40% in the longitudinal direction. The artificial leather of any one of claims 1 to 9, further comprising a punching hole, wherein the static load elongation is 15-25% in the longitudinal direction and 40-55% in the width direction, and the residual shrinkage ratio is 1.5-3.5 in the longitudinal direction. %, artificial leather that is 5-9% in the width direction. The artificial leather of any one of claims 1 to 9, further comprising a punching hole, the increase rate of the static load elongation compared to before punching is 14% to 55% in the width direction, and the increase rate of the residual shrinkage ratio in the width direction is 11% to 98% artificial leather. The artificial leather of any one of claims 1 to 9, further comprising a punching hole, wherein the tear strength is 3.8-5.5 kgf in the longitudinal direction and 4.0-4.7 kgf in the width direction. The artificial leather of any one of claims 1 to 9, further comprising a punching hole, wherein the reduction in tear strength compared to before punching is -32% to -3% in the longitudinal direction, -14% to -1.1% in the width direction Artificial leather that is. The artificial leather of any one of claims 1 to 9, further comprising a punching hole, wherein the rupture strength is 9-15kgf/cm ² in the longitudinal direction. The artificial leather of any one of claims 1 to 9, further comprising a punching hole, wherein the peel strength is 1.8-5kgf/30mm in the longitudinal direction and 1.8-5kgf/30mm in the width direction. The artificial leather of any one of claims 1 to 9, further comprising a punching hole, wherein the reduction in peel strength compared to before punching is -72% to -30% in the longitudinal direction. The artificial leather of any one of claims 1 to 9 is artificial leather for automobile interior materials. delete delete

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