JP4912493B2 - Synthetic leather for automotive interior materials - Google Patents

Description

  The present invention relates to a synthetic leather for automobile interior materials, which is a synthetic leather, but suppresses an increase in the humidity level in the palm of the same level as that of genuine leather, has less stickiness as genuine leather, and has a smooth feel.

  Synthetic leather commonly used for automobile interior materials, so-called PVC leather, is excellent in leather-like appearance, price, wear resistance, moldability, etc., and is currently used in vehicles, especially automobile interior materials such as the masses. It is used in large quantities as automotive ceiling skin materials, door trim materials, instrument panel materials, and car seat skin materials.

  However, since vinyl chloride leather contains polyvinyl chloride as a constituent component, there is a concern about generation of dioxins during incineration after disposal, and its use is being restricted due to an increase in environmental problems in recent years.

  Synthetic leather other than PVC leather is also being studied. For example, an artificial leather having a skin layer formed of a synthetic resin on a base material layer such as a nonwoven fabric and having at least one layer containing moisture-absorbing / releasing moisture-absorbing exothermic fiber or moisture-absorbing / releasing moisture-absorbing exothermic powder (patent Reference 1 (see claim 1)); synthetic leather in which a synthetic resin layer containing sericin is laminated on a fibrous base (see patent document 2 (claim 1)); a thermoplastic polyurethane elastomer foam layer and heat Synthetic leather in which non-foamed layers of plastic polyurethane elastomer are sequentially provided (refer to Patent Document 3 (Claim 1)); a non-woven fabric base material formed by entanglement of a synthetic fiber web containing a metal-plated synthetic fiber; Synthetic leather impregnated and foamed with a polyurethane resin containing powder (see Patent Document 4 (Claim 1)); has a predetermined weight tensile strength per unit area, and a multicomponent continuous filament has a fineness <0 Synthetic leather impregnated with polymer nonwoven fabric that is divided into ultra-fine continuous filaments and fixed with 2 dtex (see Patent Document 5 (claim 1)) has been proposed.

JP 2002-266113 A JP 2006-307414 A JP 2006-077349 A Japanese Patent Laid-Open No. 06-184951 Special table 2003-511568 gazette

  However, conventional automotive interior materials made of synthetic leather are not satisfactory in that they do not feel the touch when touched with skin such as hands and legs, and feel sticky and even stick to the skin. . In other words, synthetic leather for automobile interior materials has been not obtained so far, although it is a synthetic leather, it has the same level of increase in humidity inside the palm as that of genuine leather, has less stickiness than genuine leather, and has a smooth texture. It was.

  The object of the present invention is to solve the above-mentioned conventional problems, and although it is a synthetic leather, it suppresses the rise level of the humidity in the palm to the same level as that of genuine leather, and is less sticky than genuine leather. It is to provide a synthetic leather for automobile interior materials having a tactile sensation.

  The synthetic leather for automobile interior material of the present invention is a synthetic leather in which a resin layer made of a single layer or a multilayer synthetic resin is formed on a base layer of a nonwoven fabric or a woven or knitted fabric having a single layer or a multilayer structure, The resin layer contains hygroscopic fine particles, and the increase (ΔH) in the palm moisture 1 minute after the start of sweating as measured by a sweating simulation apparatus is 20% RH or less. Thereby, there is little stickiness and a synthetic leather having a smooth feel can be obtained.

  When the resin layer is a multilayer, the outermost layer of the resin layer preferably contains hygroscopic fine particles. When the outermost layer contains hygroscopic fine particles, the stickiness of the synthetic leather can be reduced, and a more smooth feel can be imparted.

The synthetic leather of the present invention preferably has an average surface friction coefficient (MIU) of 0.25 or less at a load of 1.47 N / cm ² . If the average surface friction coefficient is within the above range, the smoothness of the synthetic leather will be more excellent.

The average particle diameter of the hygroscopic fine particles is preferably 1 μm to 50 μm. The content of the hygroscopic fine particles in the resin layer is preferably ² g / m ^{2 to} 50 g / m ² . As the hygroscopic fine particles, those using 50% by mass or more of an acrylic crosslinked polymer as a raw material are suitable.

The base material layer is a nonwoven fabric having a two-layer structure in which a fiber structure constituting an upper layer and a fiber structure constituting a lower layer are laminated by mechanical entanglement, and the basis weight of the upper layer is 40 g / m ² to 150 g / m ² , the fineness of the fibers constituting the upper layer is 0.0001 dtex to 0.5 dtex, the basis weight of the lower layer is 40 g / m ^{2 to} 200 g / m ² , and the fineness of the fibers constituting the lower layer is 1.5 dtex to What is 10.0 dtex is preferable.

When the base material layer is a nonwoven fabric having a single layer or a multilayer structure, the nonwoven fabric has a density of 120 kg / m ^{3 to} 250 kg / m ³ , a burst strength of 400 N to 1000 N, and a bending resistance of 1 mm to 120 mm. Is preferred.

  In the synthetic leather for automobile interior materials of the present invention, the resin layer contains hygroscopic fine particles, and the increase in the palmar moisture of 1 minute after the start of sweating measured by the sweating simulation apparatus is suppressed to 20% RH or less. There is little stickiness like leather and a smooth touch can be achieved.

It is a figure which shows the relationship between an average surface friction coefficient and the increase ((DELTA) H) 1 minute after the start of perspiration of the moisture in a palm.

Details of the present invention will be described below.
The synthetic leather for automobile interior material of the present invention is a synthetic leather in which a resin layer made of a single layer or a multilayer synthetic resin is formed on a base layer of a nonwoven fabric or a woven or knitted fabric having a single layer or a multilayer structure, The resin layer contains hygroscopic fine particles, and the increase (ΔH) in the palm moisture 1 minute after the start of sweating as measured by a sweating simulation apparatus is 20% RH or less. In the present specification, “multilayer” means two or more layers.

  The sticky feeling that a person actually feels when touching an automobile interior material is presumed to be caused by the fact that moisture (sweat) intervening between the skin and the interior material is not processed. Therefore, the applicant used a sweating simulation device test method (skin model test method) and examined the correspondence with practical use. As a result, a synthetic leather having less stickiness and a smooth feel can be obtained by containing hygroscopic fine particles in the resin layer, and suppressing the increase (ΔH) in 1 minute after the start of sweating within 20% RH or less. As a result, the present invention was completed.

The test method is a model evaluation method considering a practical environment in which constant water vapor and heat are always supplied to the interior material surface layer. This evaluation method uses a sweating simulation measuring device (manufactured by Toyobo Co., Ltd.), water supply amount: 140 g / m ² · h, hot plate temperature: 37 ° C., sample-hot plate distance: 0.5 cm, environmental temperature and humidity : 20 ° C. × 65% RH, sweat pattern: sweating is performed for 5 minutes from the start of the test, and the temperature and humidity of the space between the hot plate and the sample are measured.

  The ΔH of the synthetic leather for automobile interior material of the present invention is 20% RH or less, preferably 18% RH or less, more preferably 16% RH or less. When the ΔH exceeds 20% RH, the feeling of stickiness of the synthetic leather for automobile interior materials becomes poor. The lower limit of ΔH is not particularly limited, but is 0% RH.

Moreover, the average surface friction coefficient (MIU) at 1.47 kgf / cm ² load of the synthetic leather for automobile interior materials is preferably 0.25 or less, more preferably 0.20 or less, and further preferably 0.18 or less. . The average surface friction coefficient is an index indicating the texture of the synthetic leather (for example, smooth feeling, roughness), and the smaller the value, the smoother the surface. When the average surface friction coefficient is 0.25 or less, the smoothness of the synthetic leather for automobile interior materials becomes more excellent. The lower limit of the average surface friction coefficient is not particularly limited, but is usually 0.10.

The basis weight of the synthetic leather for automobile interior materials is preferably 250 g / m ² or more, more preferably 300 g / m ² or more, still more preferably 350 g / m ² or more, and preferably 550 g / m ² or less, more preferably. It is 500 g / m ² or less, more preferably 450 g / m ² or less. When the weight per unit area is within the above range, the synthetic leather is excellent in mechanical characteristics and lightweight for automobile interior materials.

Base Material As the fibers constituting the base layer of the nonwoven fabric or knitted fabric having a single layer or multilayer structure, a synthetic fiber made of a thermoplastic resin is preferable. Further, as a constituent fiber, natural fiber, regenerated fiber, semi-synthetic fiber, inorganic fiber, or the like may be blended or mixed as necessary.

  The thermoplastic resin forming the synthetic fiber is not particularly limited as long as it has fiber-forming ability. For example, polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, and the main components thereof, and further isophthalic acid is used. Polyesters such as low-melting polyester used as a copolymerization component; polypropylene, high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, binary to ternary copolymerization of propylene and other α-olefins Polyolefins such as coalescence; polyamides such as polyamide 6 and polyamide 66; or a mixture or copolymer thereof can be used.

  Synthetic fibers obtained from such thermoplastic resins may be multi-component systems such as a core-sheath type, an eccentric core-sheath type, a parallel type, and a sea-island type in addition to those of a single component type, and the cross-sectional shape of the fiber There are no particular restrictions. In addition, various additives such as a matting agent, a pigment, an antioxidant, an ultraviolet absorber, a light stabilizer, a crystal nucleating agent, a flame retardant, and an acaricide may be contained as necessary.

The basis weight of the base material layer is preferably 50 g / m ² or more, more preferably 100 g / m ² or more, still more preferably 150 g / m ² or more, preferably 350 g / m ² or less, more preferably 400 g / m ^2. m ² or less, more preferably 450 g / m ² or less. When the basis weight of the base material layer is within the above range, a lightweight synthetic leather for automobile interior materials is obtained that is excellent in mechanical properties.

When using a nonwoven fabric as the base material layer, a nonwoven fabric having a two-layer structure in which a fiber structure constituting an upper layer and a fiber structure constituting a lower layer are laminated by mechanical entanglement is preferable. In particular, the basis weight of the upper layer is ^{40g / m 2 ~150g / m 2} , the fineness of the fibers constituting the upper layer is 0.0001Dtex～0.5Dtex, basis weight of the lower layer ^{40g / m 2 ~200g / m 2} , A nonwoven fabric having a two-layer structure in which the fineness of the fibers constituting the lower layer is 1.5 dtex to 10.0 dtex is preferable.

  The raw material nonwoven fabric used for the base material layer may be either a short fiber nonwoven fabric or a long fiber nonwoven fabric for both the upper layer and the lower layer, but a long fiber nonwoven fabric is preferable from the viewpoint of securing better mechanical properties. The production method is not particularly limited, but preferred methods include a spunbond method and a melt blow method for a long-fiber nonwoven fabric, and a carding method and an airlay method for a short-fiber nonwoven fabric.

  The upper layer of the raw material non-woven fabric used as the base material layer has a fineness of 0.5 dtex or less, so that it becomes a base material with high density, almost no skeletal texture, excellent in texture and flexibility preferred by consumers. Although the minimum of the fineness of an upper layer base material is not specifically limited, It is preferable from a viewpoint of maintaining intensity | strength that it is 0.0001 dtex or more. Moreover, when productivity etc. are considered, the more preferable fineness of an upper layer base material is the range of 0.01 dtex-0.4 dtex, More preferably, it is the range of 0.1 dtex-0.3 dtex.

  However, only the nonwoven fabric constituting the upper layer lacks a profound feeling and luxury, and lacks basic mechanical performance such as strength as an automobile interior material. For this reason, non-woven fabric with a fineness of 1.5 dtex to 10.0 dtex is laminated and integrated as a lower layer, and it has excellent mechanical properties, is flexible and lightweight, has very little suspicion, and has a profound and high-class feeling. Synthetic leather is obtained. When the fineness of the lower layer base material is in the range of 1.5 dtex to 10.0 dtex, a base material having both bulkiness and flexibility can be obtained. In order to obtain a more balanced substrate, the fineness of the lower layer substrate is preferably in the range of 1.5 dtex to 8.0 dtex, and more preferably in the range of 2.0 dtex to 6.0 dtex.

Basis weight of the upper substrate is preferably ^{40g / m 2 ~150g / m 2} , more preferably ^{50g / m 2 ~140g / m 2} , more preferably is at 60g / m ² ~120g / m ² . If the weight per unit area is 40 g / m ² or more, the effect of preventing bone formation due to densification is very effectively exhibited, and within a range not exceeding 150 g / m ² , mechanical entanglement with the needle punch or water punch with the lower layer is possible. Because it is done effectively.

Basis weight of the lower layer substrate is preferably ^{40g / m 2 ~200g / m 2} , more preferably ^{50g / m 2 ~180g / m 2} , more preferably is at 60g / m ² ~160g / m ² . By setting the basis weight to 40 g / m ² or more, a solid feeling and high-quality feeling of the base material can be obtained, and if it is in a range not exceeding 200 g / m ² , the superior anti-settling property due to densification of the upper layer is inhibited. This is because a substrate having an excellent texture and a heavy thickness can be obtained.

  The initial stress of the lower layer base material is preferably 0.1 N / 5 cm to 40 N / 5 cm for both warp and weft. As described above, since the upper layer having a small fineness does not satisfy the mechanical performance as an automobile interior material, it is necessary to obtain an effect of reinforcing the upper layer in the lower layer. Moreover, if the initial stress of the lower layer is in the above-mentioned range, combined with the flexibility of the upper layer, strong entanglement is obtained between the upper and lower layers, and a highly integrated laminated base material is obtained. In order to obtain a laminated base material that is more flexible, profound, and high-class, the initial stress of the lower layer is more preferably in the range of 1 N / 5 cm to 20 N / 5 cm, and more preferably 3 N / 5 cm to 10 N / 5 cm.

Upper, the density of the groups lower layer are laminated material is preferably ^{120kg / m 3 ~250kg / m 3} , more preferably ^{130kg / m 3 ~240kg / m 3} , more preferably 140 kg / m ³ ~ The range is 230 kg / m ³ . When the density of the base material is less than 120 kg / m ³ , the denseness is insufficient, which causes the occurrence of erection. On the other hand, if it exceeds 250 kg / m ³ , the thickness is lowered, and the profound feeling and luxury feeling are impaired, which is not preferable.

  Further, the burst strength of the base material on which the upper layer and the lower layer are laminated is preferably 400N to 1000N, and more preferably 500N to 900N. If it is 400 N or more, for example, even if it is used as a seat skin material for an automobile interior material after being processed into a synthetic leather, the problem of tearing at the time of expansion hardly occurs, and the application range is expanded.

  Furthermore, the bending resistance of the base material on which the upper layer and the lower layer are laminated is preferably 1 mm to 120 mm, more preferably 50 mm to 120 mm, and still more preferably 70 mm to 100 mm. This is because if it has a flexibility of 1 mm to 120 mm, it will be finished into a final product utilizing the flexibility of the base material even when processed as a synthetic leather for automobile interior materials.

Synthetic resin Examples of the synthetic resin forming the resin layer include polyurethane resin, polyamide resin, polyacrylate resin, vinyl acetate resin, and polyacrylonitrile resin. These synthetic resins may be used alone or in combination of two or more. Among these, a polyurethane resin is preferable.

  As a specific component of the polyurethane resin, generally called a polyurethane resin or a polyurethane urea resin, a polyalkylene ether glycol having a molecular weight of 400 to 4000, a polyester polyol having a hydroxyl group at the terminal, a poly ε-caprolactone polyol, or It is obtained by reacting a polycarbonate polyol or the like alone or with a mixture with an organic diisocyanate, and is obtained by extending a chain with a compound having two active hydrogens if necessary.

  Examples of the polyalkylene ether glycol include polytetramethylene ether glycol, polypropylene glycol, polyethylene glycol, glycerin propylene oxide adduct, polyether polyol having ethylene oxide added to the terminal, and vinyl monomer grafted polyether polyol. Examples of the polyester polyol include ethylene glycol, butylene glycol, hexylene glycol, diethylene glycol, dipropylene glycol, and neopentyl glycol, and other alkylene glycols and succinic acid, glutaric acid, adipic acid, sebacic acid, maleic acid, fumaric acid, Examples thereof include those obtained by reacting carboxylic acids such as phthalic acid and trimellitic acid with hydroxyl acid at the end. Examples of the polycarbonate polyol include polyethylene carbonate diol, polytetramethylene carbonate diol, and polyhexamethylene carbonate diol.

  Examples of the organic diisocyanate include aromatic isocyanates such as 2,4- and 2,6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, and xylylene diisocyanate; 1,6-hexamethylene Aliphatic isocyanates such as diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, 3-isocyanate methyl-3,5,5′-trimethylcyclohexyl isocyanate, 2,6-diisocyanate methyl caproate; Or two or more of them may be used in combination.

  Examples of the chain extender include hydrazine, ethylenediamine, tetramethylenediamine, water, piperazine, isophoronediamine, ethylene glycol, butylene glycol, hexylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, or dimethylolpropionic acid, amino acid. Glycols and diamines that can improve hydrophilicity such as ethylene oxide adducts to ethanesulfonic acid can be used alone or in combination.

  As the polyurethane resin, a polycarbonate-based polyurethane resin using a polycarbonate polyol as a constituent component is preferable because of excellent hydrolysis resistance. In particular, for the resin layer present on the outermost surface of the synthetic leather, it is preferable to use a silicone-modified polycarbonate polyurethane resin in order to improve the texture of the synthetic leather.

  The silicone-modified polycarbonate-based polyurethane has an organopolysiloxane skeleton in the molecular chain, or is sealed with a functional group that is non-reactive with an isocyanate group at the molecular chain end, for example, a trialkylsilyl group or a triarylsilyl group. A polycarbonate-based polyurethane having an organopolysiloxane skeleton.

Hygroscopic fine particles The hygroscopic fine particles are fine particles having hygroscopicity, as the name suggests. Preferred examples of such fine particles include those obtained using an acrylic crosslinked polymer as a raw material. In the present invention, 50% by mass or more (preferably 70% by mass or more, more preferably 90% by mass) of the hygroscopic fine particles. % Or more) is preferably made from an acrylic crosslinked polymer as a raw material, and the hygroscopic fine particles are preferably made only from an acrylic crosslinked polymer as a raw material.

  This “acrylic crosslinked polymer” refers to (meth) acrylic acid; (meth) acrylic acid ester such as methyl (meth) acrylate and ethyl (meth) acrylate; acrylic acid such as (meth) acrylic acid amide; A copolymer monomer composition in which another copolymer monomer is added to an acrylonitrile monomer having at least a polymerizable vinyl group and a nitrile group such as (meth) acrylonitrile, if necessary, is copolymerized It means what introduce | transduced the crosslinked structure into the acrylic polymer.

  The acrylic acid monomer or acrylonitrile monomer used for the acrylic polymer may be used alone or in combination of two or more. Further, the above-mentioned other comonomer is not particularly limited as long as it does not impair the action of the finally obtained hygroscopic fine particles. For example, vinyl halide, vinylidene halide, p-styrene sulfonate And sulfonic acid-containing monomers such as styrene and vinyl acetate, vinylidene compounds such as vinyl acetate, and the like can be used.

  For introducing the cross-linked structure, a method of adding a compound having two or more polymerizable vinyl groups as a copolymer component for forming a cross-linked structure to the above comonomer monomer composition and copolymerizing the compound can be employed. As the compound having two or more polymerizable vinyl groups, triallyl isocyanurate, triallyl cyanurate, divinylbenzene, ethylene glycol di (meth) acrylate, methylenebisacrylamide and the like are preferably used.

  Further, when the acrylic polymer is an acrylonitrile polymer obtained by copolymerizing a copolymer monomer composition in which another copolymer monomer is added to an acrylonitrile monomer as required, It is also possible to introduce a crosslinked structure by treatment with a hydrazine compound. Examples of hydrazine compounds that can be used in this case include hydrazine; hydrated hydrazine, sulfate hydrazine, hydrazine hydrochloride, hydrazine nitrate, hydrazine bromate, hydrazine carbonate, and the like; ethylenediamine, sulfate guanidine, guanidine hydrochloride, guanidine nitrate, phosphate Examples include hydrazine derivatives such as guanidine and melamine.

  One of these other comonomer, compound having two or more polymerizable vinyl groups, and hydrazine compound can be used alone or in combination of two or more.

  Each of the above acrylic cross-linked polymers has a carboxyl group or a functional group that can be modified to a carboxyl group, and the carboxyl group or a functional group that can be modified to a carboxyl group is chemically converted to a salt-type carboxyl group. By causing it to absorb, hygroscopic fine particles are obtained.

  Examples of such hygroscopic fine particles include, for example, an acrylonitrile-based crosslinked polymer in which a crosslinked structure is introduced by a hydrazine-based compound into an acrylonitrile-based polymer obtained by copolymerizing a comonomer composition containing 50% by mass or more of acrylonitrile, Alternatively, the nitrile group of an acrylonitrile-based crosslinked polymer obtained by copolymerizing a comonomer composition containing 50% by mass or more of acrylonitrile and further containing a compound having two or more polymerizable vinyl groups is converted into a salt form by hydrolysis. Examples thereof include those chemically converted to a carboxyl group and containing 1.0 mmol / g or more of the salt-type carboxyl group.

  As a more preferred embodiment, (A) an acrylonitrile-based polymer obtained by copolymerizing a comonomer composition containing 85% by mass or more of acrylonitrile has an increase in nitrogen content of 0.1 to 15.0% by mass. The remaining nitrile group of the acrylonitrile-based crosslinked polymer introduced with a crosslinked structure by treatment with a hydrazine compound is chemically converted to a salt-type carboxyl group by hydrolysis, and the salt-type carboxyl group is converted to 1 A comonomer composition comprising 0.0 mmol / g or more of hygroscopic fine particles, (B) containing 50% by mass or more of acrylonitrile, and further containing divinylbenzene or triallyl isocyanurate and other comonomer. Salt type carboxyl group by hydrolysis of nitrile group of acrylonitrile cross-linked polymer copolymerized and introduced with cross-linked structure Be those was allowed chemical transformation, hygroscopic fine particles containing salt-type carboxyl group 2.0 mmol / g or more, and the like.

  In the hygroscopic fine particles of (A), “increase in nitrogen content” means that the nitrogen content (% by mass) in the acrylonitrile polymer used as a raw material and a crosslinked structure introduced into the resin by treatment with a hydrazine compound. It means the difference in the nitrogen content (mass%) after. When the nitrogen content is below the above range, the organic fine particles are dissolved in the hydrolysis step, and a salt-type carboxyl group cannot be introduced. On the other hand, when the above range is exceeded, 1.0 mmol / g or more of the nitrile group cannot be converted into a salt-type carboxyl group. In addition, the method of introducing a hydrazine-based crosslinking into the acrylonitrile-based polymer is not particularly limited as long as the increase in the nitrogen content by the crosslinking is 0.1 to 15.0% by mass, but the hydrazine-based compound is not limited. Means for treating at a concentration of 1 to 80% by mass and a temperature of 50 to 120 ° C. for 0.2 to 10 hours are industrially preferable.

  As the hygroscopic fine particles, in addition to the acrylonitrile-based crosslinked polymer as a raw material, the hygroscopic fine particle contains 5% by mass or more of an acrylate ester, and further contains divinylbenzene or triallyl isocyanurate, and other comonomer. A methyl ester part of an acrylic ester cross-linked polymer obtained by copolymerizing a comonomer composition and introducing a cross-linked structure is chemically converted into a salt-type carboxyl group by hydrolysis, and the salt-type carboxyl Hygroscopic fine particles containing 1.0 mmol / g or more of groups can also be preferably used.

  The particle diameter of the hygroscopic fine particles is not particularly limited as long as it does not impair the mechanical properties of the synthetic leather for automobile interior materials, and can be appropriately selected according to the application. However, since the surface roughness may not be preferred by consumers when used on a handle or sheet skin material that is directly touched by a person, the average particle size is preferably 50 μm or less. More preferably, it is 30 micrometers or less, More preferably, it is 20 micrometers or less. The lower limit of the average particle size of the hygroscopic fine particles is not particularly limited, but 1 μm or more is preferable.

The content of hygroscopic fine particles in the resin layer of the synthetic leather for automobile interior materials (when the resin layer is a multilayer, the total content contained in all resin layers) is preferably ² g / m ² or more, more preferably 5 g / m ² or more. Containing ² g / m ² or more, when a person touches an automobile interior material, moisture (sweat) intervening between the skin and the interior material is quickly absorbed by the synthetic leather and does not feel sticky Finished. The content is not particularly limited, but is preferably 50 g / m ² or less, more preferably 30 g / m ² or less, and still more preferably 20 g / m ² from the finish of synthetic leather, cost performance, and the like. m ² or less.

When the resin layer is a multilayer, the outermost layer preferably contains hygroscopic fine particles. When the outermost layer contains hygroscopic fine particles, the stickiness of the synthetic leather can be reduced, and a more smooth feel can be imparted. In this case, the content of the hygroscopic fine particles in the outermost layer is preferably ² g / m ² or more, more preferably 5 g / m ² or more, preferably 40 g / m ² or less, more preferably 20 g / m 2. ² or less.

  The synthetic leather for automobile interior materials of the present invention can be produced by forming a resin layer on a base material layer. The method of forming the resin layer is not particularly limited, and a method of forming a resin layer by applying a liquefied synthetic resin with a solvent and then drying the solvent, and forming by reacting the resin after applying a liquid resin For example, a dry method such as a method for laminating; a laminating method for attaching a resin film made of a synthetic resin; a wet method for applying a liquid resin to a coagulation bath and coagulating it. In addition, the surface of the synthetic leather can be embossed or textured as necessary to obtain a desired appearance.

  In addition, when employ | adopting the said lamination method, it is preferable to use a polyurethane-type adhesive as an adhesive used for affixing a resin film in consideration of the adhesive force with an outer skin layer. Examples of the polyurethane-based adhesive include polyether-based, polyester-based, polycarbonate-based, or a composite type thereof. The adhesive preferably has a 100% modulus of the cured product of 0.5 MPa to 5 MPa, and is preferably 0.5 MPa to 3 MPa in consideration of bending resistance.

  The synthetic leather for automobile interior materials according to the present invention is a synthetic leather, and has excellent moisture absorption properties so as to suppress the increase in palm moisture equivalent to that of genuine leather, and has no sticky feeling and a smooth feel. Synthetic leather. Therefore, taking advantage of the above characteristics, it is useful for automobile interior materials, particularly steering skins, console BOX skins, shift cover materials, instrument panel materials, door trim materials, ceiling skin materials, car seat skin materials and the like. Of course, it can also be used in combination with other materials that should meet the required performance in relation to the application, and can be processed and given a shape within a range that does not degrade the performance of the present invention. Furthermore, functions such as flame retardancy, insecticidal and antibacterial properties, heat resistance, water and oil repellency, coloring, and aromaticity can be imparted by adding chemicals at any stage of commercialization.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to the following examples, and may be appropriately modified and implemented within a range that can meet the purpose described above and below. All of which are within the scope of the present invention. The measurement methods used in the examples are as follows. In the following, “%” and “part” representing the content or amount used are based on mass unless otherwise specified.

1-1. Humidity inside the palm Using a sweating simulation measurement device, water supply amount: 140 g / m ² · h, hot plate temperature: 37 ° C., sample-hot plate distance: 0.5 cm, environmental temperature and humidity: 20 ° C. × 65% RH, sweat Pattern: Sweating was carried out for 5 minutes from the start of the test, and the humidity of the space between the hot plate and the sample was measured. From the measurement results, the increase in humidity (ΔH) after one minute of sweating with respect to the humidity before the start of the test was determined.
The sweating simulation device includes a heat-producing sweating mechanism comprising a substrate having a sweating hole and a heat-producing body, a water-feeding mechanism for supplying water to the sweating hole, a heat-producing control mechanism for controlling the temperature of the heat-producing body, and temperature and humidity. It consists of sensors. The substrate is made of brass, has an area of 120 cm ² , is provided with six sweat holes, and is controlled at a constant temperature by a heat-producing body composed of a planar heater. The water supply mechanism uses a tube pump, and sends out a constant amount of water to the sweat holes of the substrate. Simulated skin made of a polyester multifilament woven fabric having a thickness of 0.1 mm is affixed to the surface of the base, whereby water discharged from the perspiration holes is spread on the surface of the base and a sweating state is created. An outer frame having a height of 0.5 cm is provided around the substrate, and the sample can be set at a position 0.5 cm away from the substrate. The temperature / humidity sensor is installed in a space between the substrate and the sample (synthetic leather), and measures the humidity of the “space surrounded by the substrate, the sample and the outer frame” when the substrate is in a sweating state.

1-2. Average surface friction coefficient (special method)
The average surface friction coefficient (MIU) was measured using a surface friction coefficient measuring device (KES-SE) manufactured by Kato Tech Co., Ltd. The measurement conditions were a standard friction element (fingerprint type), a load at friction of 1.47 N / cm ² (150 gf / cm ² ), and a measurement sensitivity L (high sensitivity 100 g / V). Other conditions such as the friction distance and the friction speed are as specified in the apparatus specification (friction distance 30 mm, analysis distance 20 mm, sample moving speed 1 mm / sec).

1-3. Paired Comparative Evaluation of Stickiness, Smoothness, and Roughness with a Monitor Using 10 monitors, the stickiness, smoothness, and roughness of a sample were determined by a paired comparison method.
The monitor was seated on a car seat installed in a constant temperature and humidity chamber controlled in an environment of 25 ° C. and 60% RH, and two types of samples to be compared were laid on the left and right seat surfaces of the car seat. Next, left and right palms of the monitor were placed on the left and right samples on the car seat seat for 1 minute. Then, a sticky feeling, a smooth feeling, and a rough feeling after 1 minute were judged. Determine whether the left or right sample is more sticky, smooth, or not rough, and after a paired comparison with all the sample combinations, according to Thurston's paired comparison method, stickiness, smoothness, The graininess was scored by standardizing from -2 to +2 points. In addition, the sticky feeling is not sticky as the score is high, and the smooth feeling is higher as the score is higher, and the feeling of smoothness is higher, and the rough feeling is higher as the score is higher.

1-4. Appearance Visually, the surface condition of the synthetic leather was confirmed, and it was confirmed that there were no defects, unevenness, and uneven coating.

1-5. Average Particle Diameter Using a laser diffraction particle size distribution analyzer “SALD-200V” manufactured by Shimadzu Corporation, water was measured as a dispersion medium, and the average particle diameter was determined from the particle diameter distribution expressed on a volume basis.

1-6. Amount of salt-type carboxyl group 1 g of a sufficiently dried sample is precisely weighed (X (g)), 200 ml of water is added thereto, and then a 1 mol / l aqueous hydrochloric acid solution is added while heating to 50 ° C. to adjust the pH to 2. Thus, all the carboxyl groups contained in the sample were H-type carboxyl groups. Then, a titration curve was obtained according to a conventional method using a 0.1 mol / l NaOH aqueous solution. From the titration curve, the consumption amount of NaOH aqueous solution consumed in the H-type carboxyl groups (Y (ml)) was determined, and the total amount of carboxyl groups contained in the sample was calculated by the following formula.
(Total amount of carboxyl groups (mmol / g)) = 0.1 × Y / X
Separately, a titration curve was similarly obtained without adjusting to pH 2 by adding a 1 mol / l hydrochloric acid aqueous solution during the above-described total carboxyl group amount measurement operation, and the amount of H-type carboxyl groups contained in the sample was obtained. From these results, the salt-type carboxyl group amount was calculated by the following formula.
(Amount of salt-type carboxyl groups (mmol / g)) = (Total amount of carboxyl groups) − (Amount of H-type carboxyl groups)

1-7. Density of non-woven fabric The weight per 1 m ³ was converted from the weight per unit area and thickness determined according to JIS-L 1913 (2010), and the density was defined as g / m ³ . Specifically, the thickness was measured by a thickness measuring instrument with a load of 2 kPa, and the density was determined by dividing the basis weight by the thickness.

1-8. Initial stress of nonwoven fabric The stress at 5% elongation in the tensile strength measured in accordance with JIS-L 1913 (2010) was defined as the initial stress. Specifically, five test pieces having a width of 5 cm and a length of 30 cm were prepared, and a tensile test was performed for each to obtain an average value. The tensile test was performed by attaching to a constant speed extension type tensile tester with a grip interval of 20 cm, and applying a load until the test piece was cut at a tensile speed of 10 cm / min.

1-9. Burst strength of nonwoven fabric JIS-L 1913 (2010) Burst strength B method (constant speed extension method) was used. Specifically, five specimens having a diameter of 8 cm were collected, and the strength to break through the specimen when a push rod having a tip radius of curvature of 1.25 cm and a diameter of 2.5 cm was pressed at a constant speed of 100 mm / min. The average value of these was calculated.

1-10. Bending softness of nonwoven fabric It conformed to JIS-L 1913 (2010). Specifically, test specimens of 20 cm in the MD direction and 2.5 cm square in the CD direction were sampled at 6 points per 1 m of the test piece full width in the CD direction, and the back and front sides based on the 41.5 ° cantilever method, a total of 12 points. The average value of these was calculated. This method is a result of bending resistance in the MD direction, and is a result of measurement as described above with the specimen direction orthogonal to the CD direction.

2. 2. Production of substrate 2-1. Nonwoven fabric (base material of Production Example 1 and Comparative Example 1)
As an upper layer base material, an unbroken short fiber composite split nonwoven fabric with a basis weight of 80 g / m ^2, which is a hollow petal split fiber composite fiber having a split fiber size of 0.24 dtex composed of polyamide 6 and polyethylene terephthalate, is prepared. did. As a lower layer base material, a filament group in which a polybutylene terephthalate resin (hereinafter abbreviated as “PBT”) is stretched by adjusting the air source pressure to a fineness of 2.0 dtex by a known spunbond method has a basis weight of 100 g. / M ² , deposited on a resin net whose speed was adjusted, and then temporarily bonded with an embossing roller to obtain a spunbonded nonwoven fabric. The initial stress of the obtained spunbonded nonwoven fabric was 18.0 N / 5 cm in the vertical direction and 7.5 N / 5 cm in the horizontal direction.
Then, the composite nonwoven fabric was obtained by carrying out the fiber entanglement of the upper layer division | segmentation fiber nonwoven fabric and the lower layer spunbond nonwoven fabric by the well-known needle punch method so that a needle may be inserted from a lower layer spunbond nonwoven fabric. Furthermore, the upper layer base material and the lower layer base material are then subjected to a high water pressure treatment by water punch, and the split fiber can be divided and laminated, and the upper layer and the lower layer can be entangled without peeling. A laminated nonwoven fabric was obtained. The density of the obtained laminated nonwoven fabric was 172 kg / m ³ , the burst strength was 760 N, the bending resistance was 110 mm in the vertical direction and 81 mm in the horizontal direction.

2-2. Knitted fabric (base materials of Production Examples 2 to 8 and Comparative Examples 2 to 8)
Using a polyester filament of 84 dtex / 36f, a tricot knitted fabric with a basis weight of 300 g / m ² was obtained.

3. Fine particles 3-1. Hygroscopic fine particles No. 1 (average particle size; 3 μm)
After charging 450 parts of acrylonitrile, 50 parts of methyl acrylate and 1181 parts of water into a 2 liter autoclave and further adding 0.5% of di-tert-butyl peroxide as a polymerization initiator with respect to the total amount of monomers, Sealed and then polymerized for 30 minutes at 120 ° C. under stirring. After completion of the reaction, the mixture was cooled to 90 ° C. while continuing stirring to obtain polymer particles having an average particle size of 2 μm. Next, 60 parts of 60% hydrazine and 850 parts of water were mixed with 100 parts of the obtained polymer particles, and crosslinking was introduced by performing hydrazine treatment at 90 ° C. for 3 hours. Sodium hydroxide was added and reacted at 120 ° C. for 2 hours. The obtained particles were washed, washed and dried, and then classified to obtain acrylic crosslinked polymer fine particles having an average particle diameter of 3 μm. The amount of the salt-type carboxyl group of the particles was 7.0 mmol / g. Moreover, the increase in nitrogen content by hydrazine treatment was 1.5% by mass.

3-2. Hygroscopic fine particles No. 2 (average particle size; 30 μm)
A monomer mixture consisting of 55 parts of acrylonitrile, 10 parts of methyl acrylate, and 35 parts of divinylbenzene is added to 300 parts of an aqueous solution containing 0.5 part of ammonium persulfate, and then 0.6 part of sodium pyrosulfite is added, followed by polymerization with a stirrer. Polymerization was carried out in a tank at 65 ° C. for 2 hours. 15 parts of the obtained particles are dispersed in 85 parts of water, and 10 parts of sodium hydroxide is added thereto, followed by hydrolysis at 90 ° C. for 2 hours, followed by washing, dehydration and drying, and acrylic crosslinking. Polymer fine particles were obtained. The average particle size of the particles was 30 μm, and the amount of salt-type carboxyl groups was 6.3 mmol / g.

3-3. PMMA particle no. 1 (average particle size; 3 μm)
Monomer by mixing 90 parts of methyl methacrylate, 10 parts of ethylene glycol dimethacrylate, 1 part of 2,2′-azobis (2,4-dimethylvaleronitrile), 10 parts of polyvinyl alcohol and 300 parts of water and stirring with a homomixer. A dispersion was prepared and polymerized at 50 ° C. for 2 hours. The obtained particles were washed with water, dehydrated, dried, and then classified to obtain polymethyl methacrylate-based fine particles having an average particle diameter of 3 μm.

3-4. PMMA particle no. 2 (average particle size; 30 μm)
Monomer by mixing 90 parts of methyl methacrylate, 10 parts of ethylene glycol dimethacrylate, 1 part of 2,2′-azobis (2,4-dimethylvaleronitrile), 10 parts of polyvinyl alcohol and 300 parts of water and stirring with a homomixer. A dispersion was prepared and polymerized at 50 ° C. for 2 hours. The obtained particles were washed with water, dehydrated, dried, and then classified to obtain polymethyl methacrylate-based fine particles having an average particle diameter of 30 μm.

4). Synthetic resin 4-1. Urethane resin As the urethane resin, a non-yellowing polycarbonate type polyurethane having a 100% modulus of 2 to 10 MPa was used.

4-2. High slip urethane resin As the high slip urethane resin, a silicone-modified non-yellowing polycarbonate polyurethane having a 100% modulus of 5 to 10 MPa was used.

5. Manufacture of synthetic leather 5-1. Production Example 1
A polyvinyl alcohol (PVA) resin having a mass ratio of 18% was adhered to the nonwoven fabric obtained above by a dip nip method using an aqueous solution. These are for imparting dimensional stability to the sheet itself and for replacing it with a urethane resin.
The polyurethane resin solution was applied with a knife coater so as to have a moisture adhesion of 730 g / m ² , the PVA resin was replaced with hot water at 60 ° C. and dried with hot air at 120 ° C. After drying, the urethane coating weight per unit area was 220 g / m ² , and wet synthetic leather was obtained. The total weight of wet synthetic leather was 400 g / m ² and the thickness was 1.3 mm. Further, apply a urethane resin dissolved in a solvent on the release paper with a comma coater so that it becomes 25 g / m ^2, and dry it, and apply an adhesive (about 30 g / m ² ) to form a dry layer. The wet synthetic leather was laminated, and then an aging treatment was performed to laminate a resin layer. Here, the total weight of the base material and the resin layer was 455 g / m ² and the thickness was 1.6 mm. Note that a polyurethane adhesive was used as the adhesive.
The highly lubricious urethane resin has hygroscopic fine particles No. 1 was mixed, and a prescribed amount was applied by gravure coating on the resin layer formed above to form an outermost layer. Synthetic leather was obtained by applying a genuine leather-like texture using release paper.

5-2. Production Example 2
A urethane resin dissolved in a solvent is applied onto a release paper with a comma coater so that it is 25 g / m ^2, and the film produced by drying is bonded to the knitted fabric coated with an adhesive (about 30 g / m ² ). Thereafter, an aging treatment was performed to form a resin layer. Here, the total weight of the base material and the resin layer was 355 g / m ² and the thickness was 0.9 mm.
The highly lubricious urethane resin has hygroscopic fine particles No. 1 was mixed, and a prescribed amount was applied by gravure coating on the resin layer formed above to form an outermost layer. Synthetic leather was obtained by applying a genuine leather-like texture using release paper.

5-3. Production Examples 3-5
Synthetic leather was obtained in the same manner as in Production Example 2 except that the content of the hygroscopic fine particles to be mixed with the highly lubricious urethane resin, or the content and the average particle size were changed.

5-4. Production Example 6
Hygroscopic fine particles No. in urethane resin dissolved in solvent. 1 was mixed and applied onto a release paper with a comma coater so as to be 25 g / m ^2, and the film produced by drying was bonded to the knitted fabric coated with an adhesive (about 30 g / m ² ), and then An aging treatment was performed to form a resin layer. Here, the total weight of the base material and the resin layer was 355 g / m ² and the thickness was 0.9 mm.
The highly lubricious urethane resin has hygroscopic fine particles No. 1 was mixed, and a prescribed amount was applied by gravure coating on the resin layer formed above to form an outermost layer. Synthetic leather was obtained by applying a genuine leather-like texture using release paper.

5-5. Production Example 7
Hygroscopic fine particles No. in urethane resin dissolved in solvent. 1 was mixed and applied onto a release paper with a comma coater so as to be 25 g / m ^2, and the film produced by drying was bonded to the knitted fabric coated with an adhesive (about 30 g / m ² ), and then Aging treatment was performed to form a resin layer (outermost layer) to obtain a synthetic leather.
That is, a synthetic leather was obtained in the same manner as in Production Example 6 except that the outermost layer was not formed with a highly slippery urethane resin.

5-6. Production Example 8
The fine particles mixed with the urethane resin are designated as PMMA particles No. A synthetic leather was obtained in the same manner as in Production Example 6 except that it was changed to 1.

5-7. Production Example 9
Fine particles mixed with the highly lubricious urethane resin are designated as PMMA particles No. A synthetic leather was obtained in the same manner as in Production Example 1 except that it was changed to 1.

5-8. Production Example 10
Fine particles mixed with the highly lubricious urethane resin are designated as PMMA particles No. A synthetic leather was obtained in the same manner as in Production Example 2 except that the number was changed to 1.

5-9. Production Example 11
Fine particles mixed with the highly lubricious urethane resin are designated as PMMA particles No. A synthetic leather was obtained in the same manner as in Production Example 2 except that the content was changed to 1.

5-10. Production Example 12
Fine particles mixed with the highly lubricious urethane resin are designated as PMMA particles No. The synthetic leather was obtained in the same manner as in Production Example 2 except that the content was changed to 2.

5-11. Production Example 13
A synthetic leather was obtained in the same manner as in Production Example 7 except that the urethane resin was not mixed with fine particles.

5-12. Production Example 14
The fine particles mixed with the urethane resin and the fine particles mixed with the highly slippery urethane resin are both PMMA particles No. A synthetic leather was obtained in the same manner as in Production Example 6 except that it was changed to 1.

5-13. Production Example 15
The fine particles mixed with the urethane resin are designated as PMMA particles No. A synthetic leather was obtained in the same manner as in Production Example 7 except that the number was changed to 1.

5-14. Production Example 16
Fine particles mixed with the highly lubricious urethane resin are designated as PMMA particles No. A synthetic leather was obtained in the same manner as in Production Example 6 except that it was changed to 1.

  Table 1 shows the composition of the synthetic leather obtained in Production Examples 1 to 16, and the evaluation results of the humidity in the palm and the average surface friction coefficient. In addition, FIG. 1 shows the relationship between the average surface friction coefficient of the synthetic leather obtained in Production Examples 1 to 16 and the increase (ΔH) in the palm humidity one minute after the start of sweating. In addition, as Reference Example 1, the same evaluation was performed on the genuine leather for car seats mounted on an actual vehicle, and the results are shown in FIG.

  Table 2 shows the subjective evaluation results of the stickiness, smoothness, and roughness of the monitor. A sticky sensation indicates that a positive score is not sticky, a smooth sensation is a positive score that feels smooth, and a rough sensation indicates that a positive score is not rough.

  From Table 1, the tendency for the increase in the palm humidity in Production Example 2 to be the smallest was observed, and then the trend for the increase in palm moisture in the order of Production Examples 6, 1, 3, and 5 was observed. Regarding Production Examples 1 to 8 and Reference Example 1 (see FIG. 1), it was confirmed that the increase in palm humidity (ΔH) after 1 minute was 20% RH or less. , A non-sticky feeling is obtained. On the other hand, the samples in Production Examples 9 to 16 all showed a rapid increase in palm humidity from the initial stage, and the ΔH value after 1 minute also showed a value of 20% RH or more. There is a tendency for the evaluation of stickiness to be bad.

  In Production Example 2, the resin layer is multi-layered, and it is surmised that the outermost layer has a hygroscopic fine particle content higher than that of the other production examples and is excellent in moisture absorption performance. In Production Example 6, hygroscopic fine particles are contained in both the urethane resin layer and the highly slipping urethane resin layer, and it is assumed that the hygroscopic property is excellent. Therefore, in these production examples 2 and 6, the increase in the palm humidity is suppressed as compared with the genuine leather of Reference Example 1, and the samples are finished to be less sticky.

  From FIG. 1, Production Example 13 had an average surface friction coefficient by a special method of 0.4 or more, Production Example 15 had 0.2, and a tendency to be slippery was observed. In addition, the increase in palm humidity after 1 minute exceeded ΔH20% RH in all the samples of Production Examples 9 to 16, and was 5% RH higher than the leather of Reference Example 1. Incidentally, it is usually said that a person can experience a difference of 5% RH or more. Therefore, compared with genuine leather, the synthetic leathers of Production Examples 9 to 16 can be said to have a great feeling of stickiness. Among them, Production Examples 13 and 15 have a high surface friction resistance and cannot have a smooth feeling. Recognize.

  In addition to the above results (ΔH: increase in palm humidity after 1 minute, MIU: average surface friction coefficient by special method, stickiness, smoothness, roughness: subjective results by monitor), appearance and cost performance are 4 Evaluation was made at the stage (◎: very good, ○: good, Δ: normal, x: poor). The results are shown in Table 3.

  From Table 3, it is presumed that the configuration of Production Example 3 is effective when the appearance and cost performance other than stickiness, smoothness, and roughness are taken into consideration. However, in Production Examples 1 to 8, the increase in palm humidity after 1 minute was 20% RH or less, and there was no stickiness and a smooth feel was obtained. Thus, Production Examples 1 to 8 were obtained. Synthetic leather can be said to be a synthetic leather for automobile interior materials that has little stickiness and a smooth feel. On the other hand, the synthetic leathers obtained in Production Examples 9 to 16 are all synthetic leather for automobile interior materials in which the increase in palm humidity after 1 minute exceeds 20% RH and the stickiness is poor. It can be said.

  In addition, the synthetic leather of the present invention uses a small amount of hygroscopic fine particles and uses a small amount of resin for imparting fine particles, and therefore has an effect of reducing the weight and is excellent in cost performance compared to conventional synthetic leather. It can be said that it is a synthetic leather for interior materials.

  The synthetic leather for automobile interior materials of the present invention is useful for automobile interior materials, particularly steering skins, console BOX skins, shift cover materials, instrument panel materials, door trim materials, ceiling skin materials, car seat skin materials, and the like.

Claims (7)

Synthetic leather for automobile interior materials in which a resin layer made of a single layer or multilayer synthetic resin is formed on a base layer of a nonwoven fabric or woven or knitted fabric having a single layer or multilayer structure,
The basis weight of the synthetic leather is 250 g / m ² or more,
The resin layer contains hygroscopic fine particles, and the increase (ΔH) in 1 minute after the start of sweating in the palm by the sweating simulation apparatus measurement is 20% RH or less,
1. Synthetic leather for automobile interior material, having an average surface friction coefficient (MIU) of 0.25 or less at a load of 1.47 N / cm ² .   The synthetic leather for automobile interior materials according to claim 1, wherein the resin layer is a multilayer and the outermost layer contains hygroscopic fine particles.   The synthetic leather for automobile interior materials according to claim 1 or 2, wherein the hygroscopic fine particles have an average particle diameter of 1 µm to 50 µm. The content of the hygroscopic fine particles of the resin ^{layer, 2g / m 2 ~50g / m} 2 automotive interior materials for artificial leather according to any one of claims 1 to 3.   The synthetic leather for automobile interior materials according to any one of claims 1 to 4, wherein 50% by mass or more of the hygroscopic fine particles is made from an acrylic crosslinked polymer. The base material layer is a nonwoven fabric having a two-layer structure in which a fiber structure constituting an upper layer and a fiber structure constituting a lower layer are laminated by mechanical entanglement,
The fineness of the fibers basis weight of the upper layer constitutes ^{40g / m 2 ~150g / m 2} , the upper layer is 0.0001Dtex～0.5Dtex,
Basis weight of the lower layer ^{40g / m 2 ~200g / m 2} , automotive interior materials for synthesis according to any one of claims 1-5 fineness of the fiber constituting the lower layer is 1.5dtex~10.0dtex leather. The base material layer is a nonwoven fabric having a single layer or a multilayer structure,
The nonwoven fabric had a density of ^{120kg / m 3 ~250kg / m 3} , burst strength 400N~1000N and bending resistance synthetic automotive interior material according to any one of claims 1 to 6 is 1mm~120mm leather.