JP5867684B2 - 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, and has a moist feel similar to that of genuine leather.

  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, car seat skin materials, and the like.

  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 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 filaments are split and impregnated with a polymer non-woven fabric being fixed 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 feel when touched with skin such as hands and legs, and feel sticky and even stick to the skin. It was. In other words, synthetic leather for automobile interior materials has not been obtained so far, although it is a synthetic leather, the level of increase in humidity in the palm of the hand is suppressed to the same level as that of genuine leather, and it has a moist feel similar to that of genuine leather.

  An object of the present invention is to solve the above-described conventional problems, and to provide a synthetic leather for automobile interior materials that is a synthetic leather and has a moist feel similar to that of genuine leather.

  As a result of intensive studies by the present inventors, in order to obtain a moist feeling, (a) less sticky feeling, (b) different from the feeling that the surface is slippery when touched, the surface is slimy, and a little resistance It was found that (c) a feeling of unevenness is small, there is no roughness, the texture is fine and smooth, and (d) it is soft to push. Finding measures to achieve each of the above-mentioned contents, and for car interior materials that are moist from 4 points of "stickiness", "smoothness and resistance", "smooth and fine texture", and "softness" It has reached the invention of synthetic leather.

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, At least one layer of the resin layer contains hygroscopic fine particles, the layer that becomes the outermost skin on the side touched by humans contains organic fine particles, and the palm moisture measured by the sweating simulation device increases 1 minute after the start of sweating (ΔH ) Is 18% RH or less, 1.47 N / cm ² load average surface friction coefficient (MIU) is 0.20 or more, surface roughness (SMD) is 2.5 μm or less, low load (0.098 N / cm ²⁾ ) The amount of compressive displacement is 0.16 mm or more. Thereby, the synthetic leather which has a moist touch is obtained.

The glass transition point (Tg) of the organic fine particles is preferably −10 ° C. or lower, the average particle diameter of the organic fine particles is 1 μm to 30 μm, and the content of the organic fine particles in the resin layer preferably is ^{0.5g / m 2 ~50g / m 2} . By adopting these configurations, a moist feel can be imparted at the moment when the synthetic leather is touched.

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.

The synthetic leather for automobile interior materials of the present invention contains hygroscopic fine particles in at least one resin layer, organic fine particles in the outermost layer, and the initiation of sweating in the palm of the hand by sweating simulation device measurement. The rise (ΔH) after 1 minute is 18% RH or less, the average surface friction coefficient (MIU) at 1.47 N / cm ² load is 0.20 or more, and the surface roughness (SMD) is 2.5 μm or less. Since the amount of compressive displacement at a low load (0.098 N / cm ² ) is 0.16 mm or more, it is possible to realize a moist feeling similar to that of genuine leather.

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, At least one layer of the resin layer contains hygroscopic fine particles, the outermost layer has organic fine particles, and the increase of the palmar humidity after the start of sweating (ΔH) measured by a sweating simulation apparatus is 18%. RH or less, average surface friction coefficient (MIU) at 1.47 N / cm ² load is 0.20 or more, surface roughness (SMD) is 2.5 μm or less, and low load (0.098 N / cm ² ) The amount of compression displacement is 0.16 mm or more. 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, it was found that the sticky feeling can be suppressed by containing hygroscopic fine particles in the resin layer and suppressing the increase (ΔH) in 1 minute after the start of perspiration of the palm to 18% RH or less. Furthermore, organic fine particles are contained in the outermost skin layer, the average surface friction coefficient (MIU) and the surface roughness (SMD) are adjusted, and the compression displacement at the time of low load (0.098 N / cm ² ) is controlled. Thus, the inventors have found that a synthetic leather having a moist feel can be obtained, thereby completing the present invention.

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 18% RH or less, preferably 16% RH or less, more preferably 15% RH or less. When the ΔH exceeds 18% RH, the sticky feeling as a synthetic leather for automobile interior materials becomes strong, and the moist feeling is lost. The lower limit of ΔH is not particularly limited, but is 0% RH.

Further, the average surface friction coefficient (MIU) at 1.47 N / cm ² load of the synthetic leather for automobile interior materials is 0.20 or more, more preferably 0.22 or more, and further preferably 0.25 or more. . The average surface friction coefficient is an index indicating the texture of the synthetic leather, and indicates that the greater the value, the greater the resistance and sliminess on the surface. When the average surface friction coefficient is 0.20 or more, the moist feeling of the synthetic leather for automobile interior materials becomes more excellent. The upper limit of the average surface friction coefficient is not particularly limited, but is usually 1.0.

  Moreover, the surface roughness (SMD) of the synthetic leather for automobile interior materials is 2.5 μm or less, more preferably 2.2 μm or less, and further preferably 2.0 μm or less. Surface roughness (SMD) is an index indicating the surface texture of synthetic leather (for example, roughness, roughness, unevenness). The smaller the value, the smaller the roughness, the less rough, unevenness, and the smoothness and texture. Gives a fine sensation and a moist feeling. Although the minimum of the said surface roughness (SMD) is not specifically limited, Usually, it is 1.0 micrometer or more.

In addition, the amount of compressive displacement of the synthetic leather for automobile interior materials at a low load (0.098 N / cm ² ) is 0.16 mm or more, more preferably 0.18 mm or more, and further preferably 0.20 mm or more. The amount of compressive displacement at low load (0.098 N / cm ² ) is an index indicating the softness of the synthetic leather, and the larger the value, the larger the amount of displacement, indicating that a soft feeling can be obtained. When a person touched an object, it was found that an object with a large amount of displacement with a little pushing force feels softer. Therefore, the amount of compression displacement at a low load (0.098 N / cm ² ) It was used as an index. The upper limit of the amount of compressive displacement at the low load (0.098 N / cm ² ) is not particularly limited, but is usually 1.0 mm or less.

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, and further preferably 350 g / m ² or more. As an upper limit, 700 g / m < ² > or less is preferable, More preferably, it is 650 g / m < ² > or less, More preferably, it is 600 g / m < ² > or less. When the weight per unit area is within the above range, the synthetic leather for automobile interior material is excellent in mechanical properties and lightweight.

Base material layer As the fiber constituting the base material layer of the nonwoven fabric or woven 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 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 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. Moreover, it is also possible to contain various additives, such as a matting agent, a pigment, antioxidant, a ultraviolet absorber, a light stabilizer, a crystal nucleating agent, a flame retardant, an acaricide, as needed.

The basis weight of the base material layer is preferably 50 g / m ² or more, more preferably 100 g / m ² or more, further preferably 150 g / m ² or more, preferably 450 g / m ² or less, more preferably 400 g / m ^2. m ² or less, more preferably 350 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 non-woven fabric having a two-layer structure in which the fineness of the fibers constituting the lower layer is 1.5 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. 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.

  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 heavy feeling and a high-class feeling, 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 if it is 150 g / m ² or less, mechanical entanglement with a needle punch or water punch with the lower layer is effective. Because it is done.

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 making the basis weight 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, it does not inhibit the excellent anti-skipping property due to the densification of the upper layer, This is because a heavy and excellent base material 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.

Resin layer The resin layer is formed from a synthetic resin, and may be a single layer or a multilayer. Examples of the synthetic resin forming each resin layer include a polyurethane resin, a polyamide resin, a polyacrylate resin, a polyvinyl acetate resin, and a 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 a terminal, a poly ε-caprolactone polyol, or It can be obtained by reacting a polycarbonate polyol or the like alone or with a mixture with an organic diisocyanate, and can be 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 an ethylene end added, and vinyl monomer grafted polyether polyol. . Examples of the polyester polyol include ethylene glycol, butylene glycol, hexylene glycol, diethylene glycol, dipropylene glycol, 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-toluylene 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, and the like. 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, etc., 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, it is preferable to use a silicone-modified polycarbonate polyurethane resin for the resin layer present on the outermost surface of the synthetic leather in order to improve the wear resistance 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. Specifically, the moisture absorption rate is more than 5% by mass, preferably 20% by mass, more preferably 35% by mass or more. The upper limit of the moisture absorption rate is not particularly limited, but is about 65% by mass.
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 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 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 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 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 And hydrazine derivatives such as guanidine and melamine.

  One of these other comonomer, compound having two or more polymerizable vinyl groups, and hydrazine-based 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. Moisture absorption / release fine particles can be obtained by caulking.

  As such moisture-absorbing / releasing fine particles, 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, etc. is obtained by hydrolysis. And those having been chemically converted to a type 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 Hygroscopic fine particles having a concentration of 0.0 mmol / g or more; (B) a comonomer composition containing 50% by mass or more of acrylonitrile, and further containing divinylbenzene or triallyl isocyanurate and other comonomer. Hydrolysis of the nitrile group of the acrylonitrile-based crosslinked polymer into which a crosslinked structure was introduced by copolymerization of Be those was allowed Manabu conversion, moisture sorption particles containing a 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 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. 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, still more preferably 20 g / m ² from the finish of synthetic leather, cost performance, and the like. ² or less.

The hygroscopic fine particles may be contained in at least one layer of the resin layer. When the resin layer is a multilayer, the hygroscopic fine particles may be contained only in any one layer, or may be contained in two or more layers. When the resin layer is a multilayer, the content of hygroscopic fine particles in the outermost layer is preferably 20 g / m ² or less, more preferably 10 g / m ² or less, and further preferably 5 g / m ² or less. By reducing the hygroscopic fine particle content in the outermost layer, the moist feeling of the synthetic leather becomes better.

When the outermost layer contains hygroscopic fine particles, the total content of the hygroscopic fine particles and the organic fine particles in the outermost layer is preferably 50 g / m ² or less, more preferably 30 g / m ² or less. More preferably, it is 20 g / m ² or less. By doing so, the number of particles contained in the outermost layer does not increase too much, and the roughness of the synthetic leather can be further reduced.

  When the resin layer is a multilayer, the layer containing hygroscopic fine particles is not particularly limited, but it is preferably contained other than the outermost layer (the outermost layer does not contain hygroscopic fine particles), and is contained in a layer adjacent to the outermost layer. More preferably. When the outermost layer does not contain hygroscopic fine particles, the resin layer formed on the layer containing the hygroscopic fine particles preferably has moisture permeability or hygroscopicity. Thereby, moisture is taken into the resin layer and absorbed by the hygroscopic fine particles.

Organic fine particles The organic fine particles mentioned above are various types such as urethane-based, acrylic-based, nylon-based, olefin-based, polytetrafluoroethylene-based fine particles and silicone-based fine particles made of a compound having a carbon atom in the basic skeleton of the structure. Organic fine particles are exemplified, but there is no particular limitation. However, unlike the hygroscopic fine particles, the organic fine particles are low in hygroscopicity. Specifically, the hygroscopicity is 5% by mass or less, preferably 3% by mass or less.
In the present invention, the glass transition point (Tg) of the organic fine particles is preferably −10 ° C. or lower, more preferably −20 ° C. or lower. When the glass transition point (Tg) of the organic fine particles is in the above range, not only the moist feeling of the synthetic leather for automobile interior materials is increased, but also the matte effect on the surface is obtained, and the design is further improved. When inorganic fine particles such as silica are used instead of organic fine particles, the matte effect on the surface can be obtained, but the surface feel is smooth and the moist feeling cannot be obtained.

  The difference (Tg−Tgr) between the glass transition point (Tg) of the organic fine particles and the glass transition point (Tgr) of the resin constituting the resin layer containing the organic fine particles is −100 ° C. to + 60 ° C. Is preferred. Within this range, resistance to resistance when touched by a person is preferable. The difference (Tg−Tgr) is more preferably −40 ° C. to + 30 ° C., and further preferably −20 ° C. to 20 ° C. Within this range, it is preferable because a sense of incongruity when touched by a person is reduced and a moist feeling is increased. The glass transition point (Tgr) of the synthetic resin forming the layer containing the organic fine particles is preferably −80 ° C. or higher, more preferably −60 ° C. or higher, further preferably −50 ° C. or higher. ° C or lower is preferable, more preferably -5 ° C or lower, and further preferably -10 ° C or lower.

  The particle diameter of the organic 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, when used on a member that is directly touched by a person, the surface roughness may not be preferred by consumers, so the average particle size is preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less. It is. The lower limit of the average particle size of the organic fine particles is not particularly limited, but is preferably 1 μm or more.

The content of the organic fine particles in the resin layer (when the resin layer is a multilayer, the total content contained in all the resin layers) is preferably 50 g / m ² or less. The content is not particularly limited, but is preferably 30 g / m ² or less, and more preferably 20 g / m ² or less, from the finish of synthetic leather, cost performance, and the like. The lower limit of the content of the organic fine particles is not particularly limited, but is preferably 0.5 g / m ² or more, more preferably 1 g / m ² or more, and further preferably 3 g / m ² or more. By containing the above amount, a moist feeling can be given at the moment when the synthetic leather is touched.

  The shape of the organic fine particles is not particularly specified, and any shape such as a spherical shape, a flat plate shape, a rod shape, an indeterminate shape, or an extremely different aspect ratio can be used without any problem. Moreover, if a glass transition point does not lose | disappear, it can also bridge | crosslink in order to provide solvent resistance. In order to impart functionality such as adhesiveness, the organic fine particles may be surface-treated with fatty acids, silane coupling agents, titanates and the like.

  The organic fine particles may be contained in the resin layer that is the outermost skin. The organic fine particles may be contained in a resin layer other than the outermost skin, but it is preferable to be contained only in the resin layer serving as the outermost skin.

  Examples of the synthetic leather for automobile interior materials of the present invention include, for example, (i) an embodiment having a single resin layer, the resin layer containing hygroscopic fine particles and organic fine particles; (ii) a multilayer resin layer And (iii) a multilayer resin layer, at least one layer does not contain hygroscopic fine particles and organic fine particles, and at least one layer contains hygroscopic fine particles, and the outermost layer contains organic fine particles. An embodiment in which hygroscopic fine particles are contained in at least one layer, and organic fine particles are contained in the outermost layer.

  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 for automobile interior materials, which is a synthetic leather and has excellent moisture absorption properties so as to keep the palm moisture level as high as genuine leather, and has a moist feel. is there. 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, 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 (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. Compression displacement at low load (0.098 N / cm ² ) The compression displacement of the sample was measured using a compression tester (KES-FB3) manufactured by Kato Tech. The pressure plate used was a 2 cm ² circular shape, and was compressed to 0.49 N / cm ² at a speed of 0.02 mm / sec, and the displacement amount at the time of 0.098 N / cm ² compression was measured.

1-4. Surface roughness (SMD)
Using a surface testing machine (KES-FB4) manufactured by Kato Tech Co., Ltd., the thickness fluctuation of the sample surface was measured. Measurement conditions were as follows: a load of 0.098 N was applied to a 0.5 mm diameter piano wire having a width of 5 mm, a friction distance of 30 mm, an analysis distance of 20 mm, and a sample moving speed of 1 mm / sec.

1-5. Paired comparative evaluation of stickiness, softness, graininess, and moist feeling by a monitor The stickiness, softness, graininess, and moistness of a sample were determined by a paired comparison method using 10 monitors.
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. And the sticky feeling after 1 minute, softness, rough feeling, and moist feeling as comprehensive evaluation were determined. Judge whether the left or right sample is more sticky, soft, rough, or moist as a comprehensive evaluation, and after paired comparison for all sample combinations, comply with Thurston's paired comparison method In addition, the stickiness, softness, roughness, and moist feeling were standardized by -2 to +2 points to score. In addition, the stickiness is higher when the score is higher, and the softness is higher as the score is higher. The soft feeling is higher as the score is higher. The higher the score, the closer to the moist feeling, but each alone could not express moist feeling, and the moist feeling was evaluated as a comprehensive evaluation. The higher the moist feeling, the higher the moist feeling.

1-6. Appearance Visually, the surface condition of the synthetic leather was confirmed, and it was confirmed that there were no defects, unevenness, and uneven coating.

1-7. 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.

1-8. 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)

1-9. Moisture absorption rate of particles The particles were sufficiently dried, and the mass (W ₀ ) in an absolutely dry state was measured. Next, the particles were conditioned for 24 hours in an environment of 20 ° C. and 65% RH, and the mass (W ₁ ) in the hygroscopic state was measured. From the mass in each state, the moisture absorption rate of the particles was calculated by the following formula.
Moisture absorption rate (% by mass) of particles = 100 × (W ₁ −W ₀ ) / W ₀

1-10. 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.

1-11. 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.

1-12. 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.

1-13. 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 Production Example 12)
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 are 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 for Production Examples 2 to 11 and 13 to 18)
Using a polyester filament of 84 dtex / 36f, a tricot knitted fabric with a basis weight of 300 g / m ² was obtained.

3. Hygroscopic 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. 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. The obtained hygroscopic fine particles No. The moisture absorption rate of 1 was 35 to 65% 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. The obtained hygroscopic fine particles No. The moisture absorption rate of 2 was 35 to 65% by mass.

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.

4). Organic fine particles 4-1. Organic fine particles No. 1 (Urethane fine particles, Art Pearl (registered trademark) series manufactured by Negami Kogyo Co., Ltd. Tg: -52 ° C., average particle size: 6 μm, moisture absorption of 3% by mass or less)
4-2. Organic fine particles No. 2 (Urethane fine particles, Art Pearl Series, Negami Kogyo Co., Ltd. Tg: −13 ° C., average particle size: 6 μm, moisture absorption of 3% by mass or less)
4-3. Organic fine particles No. 3 (Urethane-based fine particles, Art Pearl Series, Negami Kogyo Co., Ltd. Tg: -52 ° C., average particle size 35 μm, moisture absorption 3% by mass or less)

5. Inorganic fine particles No. 1 Talc (Nippon Talc Co., Ltd. Microace Series Average particle size: 5μm)

6). Synthetic resin 6-1. Urethane resin As the urethane resin, a non-yellowing polycarbonate type polyurethane having a 100% modulus of 2 to 10 MPa was used.

6-2. High slip urethane resin As the high slip urethane resin, a silicone-modified non-yellowing polycarbonate polyurethane (Tgr: −40 ° C. to −20 ° C.) having a 100% modulus of 5 to 10 MPa was used.

7). Manufacture of synthetic leather 7-1. 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, the PVA resin was replaced with hot water at 60 ° C., and dried with hot air at 120 ° C. After drying, the weight per unit area of urethane applied was 80 g / m ² to obtain wet synthetic leather. The total weight of wet synthetic leather was 260 g / m ² and the thickness was 0.8 mm. Further, the hygroscopic fine particles No. 1 are formed on a urethane resin dissolved in a solvent on a release paper. 1 is applied to the wet synthetic leather coated with a specified amount of adhesive, and then subjected to an aging treatment. A resin layer was laminated. Here, the total weight of the base material and the resin layer was 308 g / m ² and the thickness was 1.1 mm. Note that a polyurethane adhesive was used as the adhesive.
In addition, organic 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.

7-2. Production Example 2
The knitted fabric obtained above was adhered to a polyvinyl alcohol (PVA) resin having a mass ratio of 18% by the dip nip method of 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, the PVA resin was replaced with hot water at 60 ° C., and dried with hot air at 120 ° C. After drying, the weight per unit area of urethane applied was 80 g / m ² to obtain wet synthetic leather. The total weight of wet synthetic leather was 380 g / m ² and the thickness was 0.7 mm. Further, the hygroscopic fine particles No. 1 are formed on a urethane resin dissolved in a solvent on a release paper. The resin mixed with 1 is applied with a specified amount by a comma coater and dried to form a dry layer film, which is bonded to the wet synthetic leather coated with a specified amount of adhesive, and then subjected to an aging treatment, A resin layer was laminated. Here, the total weight of the base material and the resin layer was 428 g / m ² and the thickness was 0.8 mm. Note that a polyurethane adhesive was used as the adhesive.
The high lubricity urethane resin is coated with organic 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.

7-3. Production Examples 3-7
Synthetic leather was obtained in the same manner as in Production Example 2 except that the type and content of fine particles mixed with the urethane resin and the type and content of fine particles mixed with the highly lubricious urethane resin were changed.

7-4. Production Example 8
Synthetic leather was obtained in the same manner as in Production Example 2 except that the urethane resin was not mixed with fine particles, but the type and content of the fine particles mixed with the highly lubricious urethane resin were changed.

7-5. Production Example 9
Synthetic leather was obtained in the same manner as in Production Example 2 except that the kind and content of fine particles mixed with the urethane resin were changed and the fine lubricating urethane resin was not mixed with fine particles.

7-6. Production Example 10
Hygroscopic fine particles No. in urethane resin dissolved in solvent. 1. Organic fine particles No. 1 A resin mixed with 1 is applied on a release paper with a comma coater in a specified amount and dried. The film produced is bonded to the knitted fabric coated with an adhesive, and then subjected to an aging treatment to form a resin layer. did. Here, the total weight of the base material and the resin layer was 354 g / m ² and the thickness was 0.9 mm. Synthetic leather was obtained by applying a genuine leather-like texture using release paper.

7-7. Production Example 11
Hygroscopic fine particles No. in urethane resin dissolved in solvent. A resin mixed with 1 is applied on a release paper with a comma coater in a specified amount and dried. The film produced is bonded to the knitted fabric coated with an adhesive, and then subjected to an aging treatment to form a resin layer. did. Here, the total weight of the base material and the resin layer was 348 g / m ² and the thickness was 0.8 mm. The high lubricity urethane resin is coated with organic 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.

7-8. Production Example 12
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, the PVA resin was replaced with hot water at 60 ° C., and dried with hot air at 120 ° C. After drying, the weight per unit area of urethane applied was 80 g / m ² to obtain wet synthetic leather. The total weight of wet synthetic leather was 260 g / m ² and the thickness was 0.8 mm. Furthermore, PMMA fine particles No. 2 were added to a urethane resin dissolved in a solvent on a release paper. 1 is applied to the wet synthetic leather coated with a specified amount of adhesive, and then subjected to an aging treatment. A resin layer was laminated. Here, the total weight of the base material and the resin layer was 308 g / m ² and the thickness was 1.1 mm. Note that a polyurethane adhesive was used as the adhesive.
A specified amount of the high slip urethane resin was applied on the resin layer formed above by gravure coating to form the outermost layer. Synthetic leather was obtained by applying a genuine leather-like texture using release paper.

7-9. Production Example 13
The knitted fabric obtained above was adhered to a polyvinyl alcohol (PVA) resin having a mass ratio of 18% by the dip nip method of 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, the PVA resin was replaced with hot water at 60 ° C., and dried with hot air at 120 ° C. After drying, the weight per unit area of urethane applied was 80 g / m ² to obtain wet synthetic leather. The total weight of wet synthetic leather was 380 g / m ² and the thickness was 0.7 mm. Furthermore, PMMA fine particles No. 2 were added to a urethane resin dissolved in a solvent on a release paper. The resin mixed with 1 is applied with a specified amount by a comma coater and dried to form a dry layer film, which is bonded to the wet synthetic leather coated with a specified amount of adhesive, and then subjected to an aging treatment, A resin layer was laminated. Here, the total weight of the base material and the resin layer was 428 g / m ² and the thickness was 0.8 mm. Note that a polyurethane adhesive was used as the adhesive.
The high lubricity urethane resin is coated with organic 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.

7-10. Production Example 14
Synthetic leather was obtained in the same manner as in Production Example 12 except that the kind and content of fine particles mixed with the high slip urethane resin were changed.

7-11. Production Example 15
The knitted fabric obtained above was adhered to a polyvinyl alcohol (PVA) resin having a mass ratio of 18% by the dip nip method of 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, the PVA resin was replaced with hot water at 60 ° C., and dried with hot air at 120 ° C. After drying, the weight per unit area of urethane applied was 80 g / m ² to obtain wet synthetic leather. The total weight of wet synthetic leather was 380 g / m ² and the thickness was 0.7 mm. Further, the hygroscopic fine particles No. 1 are formed on a urethane resin dissolved in a solvent on a release paper. The resin mixed with 1 is applied with a specified amount by a comma coater and dried to form a dry layer film, which is bonded to the wet synthetic leather coated with a specified amount of adhesive, and then subjected to an aging treatment, A resin layer was laminated. Here, the total weight of the base material and the resin layer was 428 g / m ² and the thickness was 0.8 mm. Note that a polyurethane adhesive was used as the adhesive.
The high lubricity urethane resin is coated with inorganic 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.

7-12. Production Example 16
Synthetic leather was obtained in the same manner as in Production Example 15 except that fine particles were not mixed in the highly slippery urethane resin.

7-13. Production Example 17
Fine particles were not mixed with the urethane resin, and organic fine particles No. A synthetic leather was obtained in the same manner as in Production Example 15 except that 1 was mixed.

7-14. Production Example 18
Synthetic leather was obtained in the same manner as in Production Example 15 except that fine particles were not mixed in the urethane resin and the highly slippery urethane resin.

  Table 1 shows the composition of the synthetic leather obtained in Production Examples 1 to 18 and the evaluation results of the humidity in the palm, the average surface friction coefficient, the surface roughness, and the compression displacement at low load.

  Table 2 shows the subjective evaluation results of stickiness, softness, roughness, and moist feeling by the monitor. Stickiness is a positive score that is not sticky, softness and moistness are positive scores that are soft and moist, respectively, and the rough feeling is a positive score that is not rough. Indicates.

  From Table 1, it was confirmed that the value of the increase (ΔH) in the palm humidity after 1 minute of Production Examples 1 to 11, 15, and 16 was 18% RH or less. Also in the subjective evaluation of the monitors shown in Table 2, a non-sticky sensation is obtained in Production Examples 1 to 11, 15, and 16. On the other hand, in Production Examples 12, 13, 14, 17, and 18 in which hygroscopic fine particles are not mixed, the value of the increase (ΔH) in the palm moisture after 1 minute exceeds 18% RH. Even in the subjective evaluation, the stickiness evaluation tends to be bad.

  The average coefficient of friction (MIU) shows a value of 0.2 or more in Production Examples 1 to 11, 13, and 17, and is finished on a surface having a resistance feeling, and it is understood that the surface is finished with a moist feeling. In contrast, in Production Examples 12, 14, 15, 16, and 18, MIU is less than 0.2. Since organic fine particles are relatively soft, they have an effect of increasing MIU. However, those having no organic fine particles or those having inorganic fine particles have little effect of increasing MIU, and particularly inorganic fine particles are present. Because it tends to slip smoothly, things are finished with a moist surface.

  The surface roughness (SMD) shows a value of 2.5 μm or less in all the production examples, and it can be seen that all samples are finished to a good surface roughness level. Even in the subjective evaluation of the monitor, a result with no roughness was obtained.

  With respect to the low load compression displacement, in Production Examples 1 to 11, 13, and 17, a value of 0.16 mm or more is shown, and it can be seen that the displacement during low load compression is large. Also in the subjective evaluation of the monitor, in the production examples 1 to 11, 13, and 17, the softness is more than normal. On the other hand, in the production examples 12, 14, 15, 16, and 18, the displacement amount is less than 0.16 mm, and the monitor subjective evaluation is a negative score, and it is felt that it is not soft. I understand. The reason why the amount of compressive variation increases due to the addition of organic fine particles is not clear, but because organic fine particles are relatively soft and dispersed in the resin, the stress is dispersed and soft. The result is considered to be obtained. Although the inorganic fine particles are dispersed, it is considered that the dispersion of stress is not observed because the inorganic fine particles are relatively hard.

  The above results (ΔH: increase in palm humidity after 1 minute, MIU: average surface friction coefficient by special method, SMD: surface roughness, low load compression displacement, stickiness, softness, roughness, moist feeling: In addition to the subjective results by the monitor, the appearance and cost performance were evaluated in four stages (◎: very good, ○: good, Δ: normal, ×: poor). The results are shown in Table 3.

  From Table 3, Production Examples 1 to 11 show that the increase in palm humidity (ΔH) after 1 minute is 18% RH or less, the average coefficient of friction (MIU) is 0.2 or more, and the surface The roughness (SMD) is 2.5 μm or less, and the low load compression displacement is 0.16 mm or more. There is no problem in appearance and cost performance, and there is no stickiness in the subjective evaluation of the monitor. It can be seen that there is no feeling and a moist feeling is obtained. On the other hand, in Production Examples 12, 14, and 18, the SMD shows a good value and does not have a rough feeling, but the increase in ΔH is high, there is a sticky feeling, and the MIU value is low. In addition, the soft load is not obtained because the low load compression displacement amount is small, and a moist feeling is not obtained. In Production Examples 13 and 17, the MIU value, the SMD value, and the low load compressive displacement amount are good values, and there is no roughness and a soft tendency is obtained, but the increase in ΔH is high and there is a feeling of stickiness. The feeling that I did is not obtained. Production Examples 15 and 16 show good values in ΔH and SMD, and are finished without stickiness or roughness, but both MIU and low load compression displacement are small, and feel smooth and soft. The moist feeling is not obtained.

  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 (9)

A single layer or a nonwoven or woven or knitted fabric of the base layer has a multilayer structure, a synthetic leather resin layer is formed of single layer or multi-layer synthetic resin,
At least one of the resin layers contains hygroscopic fine particles, and the resin layer that is the outermost skin contains organic fine particles,
The content of hygroscopic fine particles in the resin layer serving as the outermost skin is 20 g / m ² or less,
The content of the hygroscopic fine particles of the resin layer is ^{5g / m 2 ~50g / m 2} ,
The increase (ΔH) in 1 minute after the start of sweating by measuring the sweating simulation apparatus is 18% RH or less,
1.47 N / cm ² load average surface friction coefficient (MIU) is 0.20 or more,
The surface roughness (SMD) is 2.5 μm or less,
A synthetic leather for automobile interior materials, wherein the amount of compressive displacement at a low load (0.098 N / cm ² ) is 0.16 mm or more.   The synthetic leather for automobile interior materials according to claim 1, wherein the glass transition point (Tg) of the organic fine particles is -10 ° C or lower.   The synthetic leather for automobile interior materials according to claim 1 or 2, wherein the average particle diameter of the organic fine particles is 1 µm to 30 µm. The content of the organic fine particles of the resin ^{layer, 0.5g / 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 the hygroscopic fine particles have an average particle diameter of 1 µm to 50 µm. The synthetic leather for automobile interior materials according to any one of claims 1 to 5, wherein the organic fine particles are urethane fine particles made of a compound having a carbon atom in the basic skeleton of the structure.   The synthetic leather for automobile interior materials according to any one of claims 1 to 6, wherein 50% by mass or more of the hygroscopic fine particles is obtained from an acrylic crosslinked polymer as a raw material. 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 1-7 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} , automobile interior materials for synthesis according to any one of claims 1-8 bursting strength is 400N~1000N and softness is 1mm~120mm leather.