WO2012077180A1 - Synthetic leather for automobile interior material use - Google Patents

Abstract

Provided is a synthetic leather for automobile interior material use, that has a non-stickiness equal to leather and is soft to touch. The synthetic leather for automobile interior material use is a synthetic leather with a resin layer, comprising a single-layer or multiple-layer synthetic resin, formed on top of a base material layer of nonwoven fabric or woven/knitted fabric with a single-layer or multilayer structure; and is characterized by the resin layer containing absorbent microparticles and the increase (ΔH)in palm humidity one minute after perspiration commences being 20%RH max. when palm humidity is measured using a perspiration simulation device for synthetic leather.

Description

Synthetic leather for automotive interior materials

[Technical Field] 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 as little 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 widely used as a car roof material, door trim material, instrument panel material, car seat skin material, and the like.

However, since PVC leather is composed of polyvinyl chloride, there is a concern about the generation of dioxins during incineration after disposal, and its use is being restricted due to the recent increase in environmental problems.

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)); having a predetermined tensile tensile strength per unit area, and a multicomponent continuous filament having a fineness of <0. Ultrafine continuous split into filaments and fixed the polymer to non-woven fabric are impregnated with synthetic leather (see Patent Document 5 (claim 1)) have been proposed having a dtex.

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 have a tactile sensation 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 materials of the present invention is a synthetic leather in which a resin layer composed of a single layer or a multilayer synthetic resin is formed on a base layer of a nonwoven fabric or woven or knitted fabric having a single layer or a multilayer structure, The resin layer contains hygroscopic fine particles, and the palm humidity rise (ΔH) 1 minute after the start of sweating is 20% RH or less in the measurement of palm moisture using a sweat simulation apparatus for synthetic leather. And 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 feeling of stickiness of the synthetic leather can be further reduced, and the smooth feel can be imparted to the synthetic leather.

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 or more and 50 μm or less. The content of the hygroscopic fine particles of the resin layer is preferably 2 g / m ² or more 50 g / m ² or less. 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 or more 150 g / m ² or less, the fineness of the fibers constituting the upper layer is 0.0001 dtex or more and 0.5 dtex or less, the basis weight of the lower layer is 40 g / m ² or more and 200 g / m ² or less, and the fineness of the fibers constituting the lower layer is 1 It is preferably 5 dtex or more and 10.0 dtex or less.

When the substrate layer is a nonwoven fabric having a single layer or a multilayer structure, the nonwoven fabric has a density of 120 kg / m ³ or more and 250 kg / m ³ or less, a burst strength of 400 N or more and 1000 N or less, and a bending resistance of 1 mm or more. It is preferable that it is 120 mm or less.

In the synthetic leather for automobile interior materials of the present invention, the resin layer contains hygroscopic fine particles, and in the measurement of the internal humidity of the synthetic leather by using a sweating simulation apparatus, the increase in the internal humidity after 1 minute of the start of sweating is 20. Since it is suppressed to not more than% RH, there is little stickiness as with genuine leather, and a smooth feel can be realized.

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 materials of the present invention is a synthetic leather in which a resin layer composed of a single layer or a multilayer synthetic resin is formed on a base layer of a nonwoven fabric or woven or knitted fabric having a single layer or a multilayer structure, When the resin layer contains hygroscopic fine particles and the moisture content in the palm of the synthetic leather is measured by a sweating simulation device, the increase in the moisture content in the palm (ΔH) 1 minute after the start of sweating (hereinafter simply referred to as “ΔH”) Is) 20% RH or less. In the present specification, “multilayer” means two or more layers.

It is presumed that the stickiness that is actually felt when a person touches an automobile interior material is because the moisture (sweat) intervening between the skin and the interior material is not treated. Therefore, the applicant used a sweating simulation device test method (skin model test method) and examined the correspondence with practical use. As a result, the resin layer contains hygroscopic fine particles, and the increase in palm humidity (ΔH) 1 minute after the start of sweating in the measurement of palm humidity with a sweating simulation device is suppressed to 20% RH or less, thereby making it sticky. As a result, it was found that a synthetic leather having a smooth feel was obtained, and the present invention was completed.

The skin model test method is a model evaluation method considering a practical environment in which constant water vapor and heat are always supplied to the surface layer of the synthetic leather. 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 carried out for 5 minutes from the start of the test, and the temperature and humidity of the space between the hot plate and the sample (synthetic leather) are measured.

The ΔH of the synthetic leather for automobile interior materials 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 a fiber 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 mixed 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 point polyesters used as copolymerization components; polypropylene, high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, binary or ternary copolymer of propylene and other α-olefins Polyolefins such as polymers; 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 multicomponent 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 shape of the fiber cross section There are no particular restrictions. In addition, the synthetic fiber may contain 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 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 40 g / m ² or more and 150 g / m ² or less, the fineness of the fibers constituting the upper layer is 0.0001 dtex or more and 0.5 dtex or less, and the basis weight of the lower layer is 40 g / m ² or more and 200 g / m. ² or less, a nonwoven fabric having a two-layer structure fineness of the fiber constituting the lower layer is less than 10.0dtex than 1.5dtex are preferred.

The raw 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 ensuring better mechanical properties. Although the manufacturing method is not particularly limited, 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.

By setting the fineness of the fibers constituting the upper layer base material of the raw material nonwoven fabric to be the base material layer to 0.5 dtex or less, the denseness is high, there is almost no erection, the texture preferred by consumers, and excellent flexibility It becomes a base material. Although the minimum of the fineness of the fiber which comprises 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. In consideration of productivity and the like, the fineness of the fibers constituting the upper layer base material is more preferably 0.01 dtex or more, further preferably 0.1 dtex or more, more preferably 0.4 dtex or less, and still more preferably 0. .3 dtex or less.

However, only the nonwoven fabric constituting the upper layer lacks a solid feeling and luxury, and lacks basic mechanical performance such as strength as an interior material for automobiles. Therefore, as a lower layer, a non-woven fabric having a fiber fineness of 1.5 dtex or more and 10.0 dtex or less is laminated and integrated so that it has excellent mechanical properties, is flexible, lightweight, has very little boneiness, has a profound feeling, and a high-class feeling. A certain leather for automobile interior materials is obtained. When the fineness of the fibers constituting the lower layer base material is 1.5 dtex or more and 10.0 dtex or less, a base material having both bulkiness and flexibility can be obtained. In order to obtain a more balanced substrate, the fineness of the fibers constituting the lower layer substrate is more preferably 1.5 dtex or more, further preferably 2.0 dtex or more, more preferably 8.0 dtex or less, and still more preferably. It is 6.0 dtex or less.

Basis weight of the upper substrate, 40 g / m ² or more, more preferably 50 g / m ² or more, more preferably 60 g / m ² or more, preferably 150 g / m ² or less, more preferably 140 g / m ² or less, more preferably 120 g / m ² or less. If the basis weight of the upper layer base material is 40 g / m ² or more, the anti-settling effect by densification is exhibited extremely effectively, and if it is 150 g / m ² or less, needle punch or water punch with the lower layer base material, etc. The mechanical entanglement is effectively done.

Basis weight of the lower layer substrate, 40 g / m ² or more, more preferably 50 g / m ² or more, still more preferably 60 g / m ² or more, preferably 200 g / m ² or less, more preferably 180 g / m ² or less, more preferably 160 g / m ² or less. If the basis weight of the lower layer base material is 40 g / m ² or more, a heavy feeling and high-class feeling of the base material can be obtained, and if it is 200 g / m ² or less, the excellent anti-settling property due to densification of the upper layer is inhibited. Thus, a substrate having an excellent texture and a heavy thickness can be obtained.

Moreover, it is preferable that the initial stress of the lower layer base material is 0.1 N / 5 cm or more and 40 N / 5 cm or less in both warp and weft. As described above, since the upper layer having a small fineness of the constituent fibers does not satisfy the mechanical performance as the automobile interior material, it is necessary to obtain the 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 substrate having a more flexible and heavy feeling and a high-class feeling, the initial stress of the lower layer is more preferably 1 N / 5 cm or more, further preferably 3 N / 5 cm or more, and more preferably 20 N / 5 cm or less. More preferably, it is 10 N / 5 cm or less.

Upper, the density of the groups lower layer are laminated material, preferably 120 kg / m ³ or more, more preferably 130 kg / m ³ or more, still more preferably 140 kg / m ³ or more, preferably 250 kg / m ³ or less, More preferably, it is 240 kg / m ³ or less, and further preferably 230 kg / m ³ or less. If the density of the base material is 120 kg / m ³ or more, the denseness is improved and the occurrence of erection can be further suppressed. Moreover, if the density of a base material is 250 kg / m < ³ > or less, thickness will not fall too much and a heavy feeling and a high-class feeling will become favorable.

Further, the burst strength of the base material on which the upper layer and the lower layer are laminated is preferably 400N or more and 1000N or less, more preferably 500N or more and 900N or less. 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.

Further, the bending resistance of the base material on which the upper layer and the lower layer are laminated is preferably 1 mm or more and 120 mm or less, more preferably 50 mm or more and 120 mm or less, and further preferably 70 mm or more and 100 mm or less. This is because if it has a flexibility of 1 mm or more and 120 mm or less, 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.

Specific examples of the constituent component of the polyurethane resin generally include a polyurethane resin and a polyurethane urea resin. These are obtained by reacting a polyol such as a polyalkylene ether glycol having a molecular weight of 400 to 4000, a polyester polyol having a hydroxyl group at a terminal, a poly ε-caprolactone polyol or a polycarbonate polyol, alone or as a mixture, with an organic diisocyanate. If necessary, the chain may be extended with a compound having two active hydrogens.

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 alkylene glycols such as ethylene glycol, butylene glycol, hexylene glycol, diethylene glycol, dipropylene glycol, and neopentyl glycol, and succinic acid, glutaric acid, adipic acid, sebacic acid, maleic acid, and fumaric acid. , Carboxylic acid such as phthalic acid and trimellitic acid, and the like which are obtained by reacting with hydroxyl acid at the end. Examples of the polycarbonate polyol include polyethylene carbonate diol, polytetramethylene carbonate diol, and polyhexamethylene carbonate diol. These may be used alone or in combination of two or more.

Examples of organic diisocyanates 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 And aliphatic isocyanates such as diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, 3-isocyanate methyl-3,5,5′-trimethylcyclohexyl isocyanate, and 2,6-diisocyanate methyl caproate. These may be used alone or in combination of two or more.

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

The polyurethane resin is preferably a polycarbonate-based polyurethane resin using a polycarbonate polyol as a constituent component because of its 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. Preferable examples of such fine particles include those obtained using an acrylic cross-linked polymer as a raw material. In the present invention, it is preferable that 50% by mass or more (preferably 70% by mass or more, more preferably 90% by mass or more) of the hygroscopic fine particles is obtained from an acrylic crosslinked polymer as a raw material. It is preferable that it consists only of what used the acrylic type 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 amide; A copolymer monomer composition in which other copolymer monomers are 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 monomer or acrylonitrile monomer used in the above acrylic polymer may be used alone or in combination of two or more. The 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-styrenesulfonate And the like, and sulfonic acid-containing monomers and salts thereof, vinyl compounds such as styrene and vinyl acetate, vinylidene compounds, and the like can be used.

For the introduction of the crosslinked structure, a method of adding a compound having two or more polymerizable vinyl groups as a copolymerization component for forming a crosslinked structure to the above copolymerizable 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 And hydrazine derivatives such as guanidine and melamine.

The above-mentioned other comonomer, a compound having two or more polymerizable vinyl groups, and a hydrazine compound can be used singly 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, these polymers are used for the 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. Examples thereof include those obtained by chemically converting a nitrile group therein to a salt-type carboxyl group by hydrolysis and containing 1.0 mmol / g or more of the salt-type carboxyl group.

In a more preferred embodiment, (A) an acrylonitrile 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 containing 0.0 mmol / g or more of hygroscopic fine particles, (B) 50% by mass or more of acrylonitrile, and further containing divinylbenzene or triallyl isocyanurate and other comonomer. Hydrolysis of nitrile group of acrylonitrile cross-linked polymer copolymerized and introduced cross-linked structure into salt-type carboxyl group by hydrolysis Be those was allowed Manabu conversion, 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 for introducing a crosslinking with a hydrazine compound to an 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 compound is not limited. Means for treatment 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 above-mentioned acrylonitrile-based cross-linked polymer as a raw material, it 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 depending on 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 30 μm or less, More preferably, it is 20 μm 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. By containing ² g / m ² or more of hygroscopic fine particles, moisture (sweat) intervening between the skin and the interior material is quickly absorbed by the synthetic leather when a person touches the interior material of the car, and the sticky feeling Finished in something that does not feel. The content is not particularly limited, but is preferably 50 g / m ² or less, more preferably 30 g / m ² or less, and even more preferably 20 g in consideration of 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 adopting the above-mentioned laminating method, it is preferable to use a polyurethane-based adhesive as an adhesive used for attaching the resin film in consideration of an adhesive force with the 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 or more and 5 MPa or less, and is preferably 0.5 MPa or more and 3 MPa or less in consideration of bending resistance.

The synthetic leather for automobile interior materials according to the present invention is a synthetic leather, has a low ΔH (increase value of palm humidity), is excellent in moisture absorption characteristics, and has a smooth feel without stickiness. . 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, it is also possible to impart functions such as flame retardancy, insecticidal antibacterial properties, heat resistance, water and oil repellency, coloring, and aromaticity 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, ambient 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 heat plate having a sweating hole and a heat producing body, a water supply mechanism for supplying water to the sweating hole, a heat producing control mechanism for controlling the temperature of the heat producing body, It consists of a humidity sensor. The base of the hot plate 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. The hot plate is made by attaching simulated skin made of polyester multifilament woven fabric with a thickness of 0.1 mm to the surface of the substrate, which spreads the water discharged from the sweat holes to the surface of the substrate and creates a sweating state. It is. 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 hot plate 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 sweat state.

1-2. Average surface friction coefficient (special method)
The average surface friction coefficient (MIU) was measured using a surface friction coefficient measuring instrument (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 specifications (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 roughness was standardized from -2 to +2 points to score. 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 size 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 size was determined from the particle size 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 It was converted into a weight per 1 m ³ from the basis weight 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 Initial stress was defined as stress at 5% elongation in tensile strength measured according to JIS-L 1913 (2010). Specifically, five test pieces having a width of 5 cm and a length of 30 cm were prepared, and a tensile test was performed on each of them 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. Rupture strength of non-woven fabric This was in accordance with JIS-L 1913 (2010) burst strength method B (constant speed extension method). 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. Flexibility of nonwoven fabric 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. Further, 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 450 parts of acrylonitrile, 50 parts of methyl acrylate and 1181 parts of water were charged into a 2 liter autoclave, di-tert-butyl peroxide as a polymerization initiator was added in an amount of 0.5% based on 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. Subsequently, 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, 10 parts of sodium hydroxide is added thereto, and a hydrolysis reaction is performed at 90 ° C. for 2 hours, followed by washing, dehydration and drying, and acrylic crosslinking. Polymer fine particles were obtained. The average particle diameter 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, non-yellowing polycarbonate type polyurethane having a 100% modulus of 2 MPa or more and 10 MPa or less 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 MPa 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 to 25 g / m ^2, and dry the film to be a dry layer, and apply an adhesive (about 30 g / m ² ). 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 was applied onto the release paper with a comma coater so as to be 25 g / m ² and dried to prepare a film. This film was laminated 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.

5-3. 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 palm humidity and the average surface friction coefficient. 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.

In addition, 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, there was a tendency that the increase in the palm humidity in Production Example 2 was the smallest, and then the increase in the palm humidity was seen in the order of Production Examples 6, 1, 3, and 5. 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 the content of hygroscopic fine particles in the outermost layer is larger than in other production examples, and it is presumed that the hygroscopic performance is excellent. 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, in Production Example 13, the average surface friction coefficient was 0.4 or more, and a tendency to be difficult to slip was observed. Further, in all samples of Production Examples 9 to 16, the increase in palm humidity after 1 minute exceeded ΔH 20% RH, which was 5% RH higher than Reference Example 1 (genuine leather). Incidentally, it is usually said that a person can experience a difference of 5% RH or more. Therefore, it can be said that the synthetic leathers of Production Examples 9 to 16 have a great stickiness when compared with genuine leather. Among these, it can be seen that Production Example 13 has a high surface friction resistance and does not give a smooth feeling.

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 inferred 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 the palmar humidity after 1 minute was 20% RH or less, and there was no stickiness and a smooth feel was obtained. Thus, the 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 leathers 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 automotive interior materials of the present invention is useful for automotive 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 (8)

1. Synthetic leather 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 knitted fabric having a single layer or multilayer structure,
   The resin layer contains hygroscopic fine particles, and
   A synthetic leather for automobile interior materials characterized in that an increase in palm humidity (ΔH) 1 minute after the start of sweating is 20% RH or less in the measurement of palm humidity with a sweating simulation device for synthetic leather.
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.
3. The synthetic leather for automobile interior materials according to claim 1 or 2, wherein an average surface friction coefficient (MIU) at a load of 1.47 N / cm ² is 0.25 or less.
4. The synthetic leather for automobile interior materials according to any one of claims 1 to 3, wherein the hygroscopic fine particles have an average particle diameter of 1 µm to 50 µm.
5. The synthetic leather for automobile interior materials according to any one of claims 1 to 4, wherein the content of the hygroscopic fine particles in the resin layer is 2 g / m ² or more and 50 g / m ² or less.
6. The synthetic leather for automobile interior materials according to any one of claims 1 to 5, wherein 50% by mass or more of the hygroscopic fine particles is made from an acrylic crosslinked polymer.
7. 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 basis weight of the upper layer is 40 g / m ² or more and 150 g / m ² or less, and the fineness of the fibers constituting the upper layer is 0.0001 dtex or more and 0.5 dtex or less,
   The automobile interior material according to any one of claims 1 to 6, wherein the basis weight of the lower layer is 40 g / m ² or more and 200 g / m ² or less, and the fineness of the fibers constituting the lower layer is 1.5 dtex or more and 10.0 dtex or less. Synthetic leather.
8. The base material layer is a nonwoven fabric having a single layer or a multilayer structure,
   The automobile interior according to any one of claims 1 to 7, wherein the nonwoven fabric has a density of 120 kg / m ³ or more and 250 kg / m ³ or less, a burst strength of 400 N or more and 1000 N or less, and a bending resistance of 1 mm or more and 120 mm or less. Synthetic leather for materials.

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