JP2015168907A - Artificial leather - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an artificial leather which does not have a sticky feeling as a real leather does, has a dry touch, is unlikely to become hot in sunlight even if it is black or deep in color, and is excellent in fading resistance.SOLUTION: The artificial leather comprises a substrate layer, a resin layer provided on the substrate layer; and an outermost surface layer provided on the resin layer. The resin layer contains hygroscopic fine particles and an infrared ray reflection pigment. The outermost surface layer contains 0.2 g/mor more and 1 g/mor less of the hygroscopic fine particles.

Description

  The present invention relates to a synthetic leather that is synthetic leather but does not feel sticky like genuine leather, has a smooth texture, and is not easily heated under sunlight even when it is black or dark.

  Conventionally, black or dark synthetic leather is preferably used for design in automobile interior materials such as instrument panel materials and car seat skin materials, and motorcycle seat materials. In this case, synthetic leather is preferably black or dark. In order to exhibit color, carbon black pigments having inexpensive and stable physical properties have been widely used. However, since carbon black pigments have a high infrared absorptivity, the use of synthetic leather containing these for the above-mentioned purposes raises the problem that the surface temperature rises significantly when exposed to sunlight for a long time. there were.

  Therefore, as a skin material that does not heat even when exposed to sunlight, a skin material in which an infrared reflective pigment is contained in a synthetic resin layer instead of a carbon black pigment has been proposed (Patent Document 1). However, a skin material using an infrared reflective pigment has a problem in fading resistance, and when used as a sheet material, color transfer may occur due to repeated rubbing.

  On the other hand, in recent years, with the real intentions of consumers increasing, synthetic leather is required to have a tactile sensation closer to that of genuine leather (for example, a smooth tactile sensation that is not sticky like genuine leather). As a synthetic leather that meets such demands, a synthetic leather has been proposed in which an outermost layer containing hygroscopic fine particles in a resin is provided on a base material layer such as a nonwoven fabric (Patent Document 2).

JP 2001-114149 A Japanese Patent No. 4912493

  In the present invention, in view of the circumstances as described above, there is no sticky feeling like genuine leather, it has a smooth texture, it is not easily heated under sunlight even in black or dark color, and it is also resistant to fading The challenge was to provide excellent synthetic leather.

  As a result of intensive studies to solve the above problems, the present inventors have provided a resin layer containing an infrared reflective pigment on a base material layer, and further, an outermost layer containing hygroscopic fine particles on the resin layer It has been found that the temperature rise due to infrared absorption can be suppressed by the resin layer, and good fading resistance can be obtained with the outermost layer without causing color transfer even by repeated rubbing. However, in this case, if the outermost layer contains moisture-absorbing fine particles that do not have a sticky feeling like genuine leather and can sufficiently express the smooth touch, a new problem arises that the outermost layer is whitened. I also found. Therefore, as a result of further studies to avoid the problem of whitening, moisture contained in both the resin layer and the outermost layer is contained in the hygroscopic fine particles so that the moisture absorbed can be transmitted to the base material layer. By controlling the content of the hygroscopic fine particles in the outermost layer to a specific amount or less, it was found that white leather was prevented and there was no stickiness like genuine leather, and a smooth touch could be expressed, and the present invention was completed. did.

That is, the synthetic leather according to the present invention includes a base material layer, a resin layer provided on the base material layer, and an outermost layer provided on the resin layer, and the resin layer is hygroscopic. Fine particles and an infrared reflective pigment are contained, and the outermost layer contains hygroscopic fine particles of 0.2 g / m ² or more and 1 g / m ² or less. The outermost layer preferably contains a urethane resin.

  In a preferred embodiment of the synthetic leather of the present invention, when a friction test is performed with a load of 4.9 N using a Gakushin type friction tester with a dry cloth or sweat cloth attached to the friction element, in a gray scale for contamination specified in JIS-L0805. The number of frictions for maintaining the fourth grade is 500 times or more in the case of dry cloth, and 200 times or more in the case of sweat cloth. In a preferred embodiment of the synthetic leather of the present invention, when light is irradiated from a distance of 90 cm using a 400 W metal halide lamp, the average surface temperature from 5 minutes to 10 minutes after the start of irradiation is less than 60 ° C. . Furthermore, in a preferred embodiment of the synthetic leather of the present invention, the increase (ΔH) in the palmar humidity after 1 minute of sweating is 20% RH or less in the sweat test by the sweat simulation apparatus.

  Since the synthetic leather of the present invention contains an infrared reflective pigment in the resin layer, even if it is black or dark, it is difficult to be heated under sunlight, and the outermost layer is provided on the resin layer. Therefore, it is excellent in fading resistance. In addition, the synthetic leather of the present invention has hygroscopic fine particles in both the resin layer and the outermost layer and the content of the hygroscopic fine particles in the outermost layer is controlled to a specific amount or less, so that it does not whiten, Thus, there is no stickiness and a smooth touch can be expressed.

  The synthetic leather of the present invention includes a base material layer, a resin layer provided on the base material layer, and an outermost layer provided on the resin layer. Hereinafter, each layer will be described.

1. Base material layer The base material layer is not particularly limited, but usually a nonwoven fabric or a woven or knitted fabric is preferably used. The base material layer may be a single layer or may have a multilayer structure.
Synthetic fibers made of thermoplastic resin are preferable as the fibers constituting the nonwoven fabric or woven or knitted fabric, but natural fibers, regenerated fibers, semi-synthetic fibers, inorganic fibers (glass fibers, etc.), etc. are blended or mixed as necessary. May be fine.

  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 copolymerization component; 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 multi-component systems such as a core-sheath type, an eccentric core-sheath type, a parallel type, and a sea-island type in addition to those of a single component type, and the cross-sectional shape of the fiber There are no particular restrictions.

  The constituent fibers of the nonwoven fabric or woven or knitted fabric contain various additives such as matting agents, pigments, antioxidants, ultraviolet absorbers, light stabilizers, crystal nucleating agents, flame retardants, and mite-proofing agents as necessary. Can be impregnated.

  When a woven or knitted fabric is used as the base material layer, the weaving method of the woven fabric and the knitting method of the knitted fabric are not particularly limited. For example, in the case of a knitted fabric, knitted fabrics such as circular knitting and warp knitting can be mentioned, and warp knitting is particularly preferable, and tricot knitted fabric and raschel knitted fabric are more preferable. Woven knitted fabrics are thin and lightweight, and in the case of woven fabrics, they have the advantage of being excellent in strength and abrasion, and in the case of knitted fabrics, there are advantages that they have both extensibility and soft texture.

  When using a nonwoven fabric as a base material layer, either a short fiber nonwoven fabric or a long fiber nonwoven fabric may be used, but a long fiber nonwoven fabric is preferable from the viewpoint of securing better mechanical properties. The method for producing the nonwoven fabric is not particularly limited, but preferably, a spunbond method or a melt blow method is used for a long-fiber nonwoven fabric, and a carding method or an airlay method is used for a short-fiber nonwoven fabric. As the nonwoven fabric, in particular, 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 suitable.

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 or less, more preferably 350 g / m ² or less. If the basis weight of the base material layer is within the above range, a synthetic leather that is lightweight and excellent in mechanical properties can be obtained.

  The thickness of the base material layer is preferably 500 μm or more and 1000 μm or less, more preferably 700 μm or more and 900 μm or less. If the thickness of the base material layer is within the above range, a synthetic leather that is lightweight and excellent in mechanical properties can be obtained.

2. Resin layer The resin layer in the present invention contains hygroscopic fine particles and an infrared reflective pigment together with a synthetic resin. By containing hygroscopic fine particles in the resin layer in addition to the outermost layer to be described later, it is possible to sufficiently develop a tactile sensation such as smooth leather without stickiness. In addition, instead of carbon black pigment, which has been widely used to develop black or dark color, it has been exposed to sunlight for a long time by adding infrared reflective pigment to make the resulting synthetic leather black or dark. However, the effect is that it is difficult to get hot.

  The thickness of the resin layer is not particularly limited, but if it is too thin, durability such as abrasion resistance may be insufficient, and is preferably 10 μm or more, and more preferably 20 μm or more. On the other hand, if the thickness of the resin layer is too thick, the handleability and lightness during post-processing may be impaired. Therefore, the thickness is preferably 100 μm or less, more preferably 70 μm or less.

2.1. Synthetic resin Although the synthetic resin which comprises a resin layer is not restrict | limited in particular, For example, a polyurethane resin, a polyamide resin, a polyacrylate resin, a polyvinyl acetate resin, a polyacrylonitrile resin etc. are mentioned. These synthetic resins may be used alone or in combination of two or more. Among these, a polyurethane resin is preferable.

  The component of the polyurethane resin is generally called a polyurethane resin or a polyurethane urea resin, and includes a polyalkylene ether glycol having a molecular weight of 400 to 4000, a polyester polyol having a hydroxyl group at the terminal, a polyε-caprolactone polyol, a polycarbonate polyol, etc. Or what is obtained by mixing and making it react with organic diisocyanate is mentioned. If necessary, these can be chain-extended with a compound having two active hydrogens (chain extender).

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, vinyl monomer grafted polyether polyol, and the like. .
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 fumar. What is obtained by making it react with carboxylic acids, such as an acid, a phthalic acid, and trimellitic acid, so that a terminal may become a hydroxyl acid is mentioned.
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- or 2,6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, and xylylene diisocyanate; 1,6-hexa Aliphatic isocyanates such as methylene diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, 3-isocyanate methyl-3,5,5′-trimethylcyclohexyl isocyanate, 2,6-diisocyanate methyl caproate, and the like. May be used alone or in combination of two or more.

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

  As the polyurethane resin, a polycarbonate-based polyurethane resin using a polycarbonate polyol as a constituent component is preferable because of excellent hydrolysis resistance. In particular, in order to improve the strength of synthetic leather and enhance durability, it is preferable to use a silicone-modified polycarbonate-based polyurethane resin (high slip urethane resin).

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

2.2. Hygroscopic fine particles As the name suggests, hygroscopic fine particles are fine particles having hygroscopic properties. The moisture absorption rate of the hygroscopic fine particles is preferably more than 5% by mass, more preferably 20% by mass or more, and further preferably 35% by mass or more. The upper limit of the moisture absorption rate is not particularly limited, but is about 65% by mass. Specific examples of such fine particles preferably include those obtained using an acrylic cross-linked polymer as a raw material. The hygroscopic fine particles are preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 90% by mass or more, and particularly preferably 100% by mass using the acrylic crosslinked polymer as a raw material. . The hygroscopic fine particles may be only one type or two or more types.

  The acrylic crosslinked polymer is an acrylic monomer such as (meth) acrylic acid; (meth) acrylic acid ester such as methyl (meth) acrylate and ethyl (meth) acrylate; (meth) acrylic amide; Or an acrylic copolymer obtained by copolymerizing a comonomer composition such that (meth) acrylonitrile or the like is added to the acrylonitrile monomer having at least a polymerizable vinyl group and a nitrile group, if necessary, with another comonomer. It means the one in which a crosslinked structure is introduced into the polymer. In addition, an acrylic acid type monomer or an acrylonitrile type monomer may be used individually by 1 type, and may use 2 or more types together.

  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-styrene sulfonate, etc. A sulfonic acid-containing monomer and a salt thereof, vinyl compounds such as styrene and vinyl acetate, vinylidene compounds, and the like can be used. In addition, another copolymerization monomer may be used individually by 1 type, and may use 2 or more types simultaneously.

  For the introduction of the cross-linked structure, a compound having two or more polymerizable vinyl groups as a copolymer component for forming a cross-linked structure is further added to the comonomer composition for obtaining the acrylic polymer. A method of copolymerization 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. In addition, the compound which has a 2 or more polymerizable vinyl group may be used individually by 1 type, and may use 2 or more types simultaneously.

  When the acrylic polymer is an acrylonitrile polymer obtained by copolymerizing a copolymer monomer composition obtained by adding another copolymer monomer 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. In addition, a hydrazine type compound may be used individually by 1 type, and may use 2 or more types simultaneously. The method for introducing the crosslinking into the acrylonitrile polymer by using the hydrazine compound is not particularly limited, but means for treating the hydrazine compound concentration at 1 to 80% by mass at a temperature of 50 to 120 ° C. for 0.2 to 10 hours. Is industrially preferred.

  Each of the acrylic crosslinked 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. Thus, hygroscopic fine particles can be obtained.

  The particle diameter of the hygroscopic fine particles is not particularly limited as long as it does not impair the mechanical properties of the resulting synthetic leather, and can be appropriately selected depending on the application. However, since the surface roughness may not be preferred by consumers depending on the application, the volume average particle size is preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less. The lower limit of the volume average particle diameter of the hygroscopic fine particles is not particularly limited, but is preferably 1 μm or more.

The content of the hygroscopic fine particles in the resin layer is preferably 0.5 g / m ² or more, more preferably 1 g / m ² or more, further preferably 2 g / m ² or more, and further preferably 3 g / m ^2. As described above, more preferably 4 g / m ² or more. If the content of the hygroscopic fine particles in the resin layer is too small, stickiness may not be sufficiently suppressed, and a tactile sensation such as genuine leather may not be obtained. From the viewpoint of tactile sensation, the higher the content of hygroscopic fine particles in the resin layer, the better. However, if it is too much, the bending resistance tends to decrease, and the hue expressed by the infrared reflective pigment is thin. It may change (for example, black becomes gray) and it may become difficult to express a desired color. Therefore, in order to develop flex resistance and a desired color, the content of the hygroscopic fine particles in the resin layer is preferably 16 g / m ² or less, more preferably 15 g / m ² or less, and still more preferably. It is 10 g / m ² or less, particularly preferably 5 g / m ² or less.

2.3. Infrared reflective pigment In the present invention, the infrared reflective pigment refers to a sample film produced by the following film production method, having an average reflectance of 780 to 1800 nm (near infrared region) of 20% or more and 400 to 760 nm (visible). This means a pigment having an average absorptance in the light region of 70% or more, and is usually black or dark.
[Method for producing sample film for measuring reflectance and transmittance]
7 parts by mass of a pigment, 100 parts by mass of a polyurethane resin (for example, polycarbonate-based polyurethane resin: “Crisbon (registered trademark) NY-373” manufactured by DIC Corporation, solid content concentration: 20% by mass), and a solvent (for example, dimethylformamide ( DMF)) The coating solution obtained by mixing 40 parts by weight was applied to the release paper so that the dry film thickness was 20 μm, dried, and the release paper was peeled off from the obtained film with release paper to obtain a sample. Let's get a film.

The average reflectance in the near-infrared region and the average absorptance in the visible light region are measured using, for example, a self-recording spectrophotometer (“UV-3150” manufactured by Shimadzu Corporation), and the transmittance and reflection from the wavelength region of 300 nm to 1800 nm. It can be obtained by measuring the spectrum of the rate, calculating the absorptance by the following formula, and calculating the average value in the corresponding wavelength region.
Absorptivity = 100− (transmittance + reflectance)

The infrared reflective pigment can be selected from organic pigments such as quinone, perylene, azomethine, and phthalocyanine, and inorganic pigments such as titanium oxide, iron oxide, and complex oxide. There may be only 1 type of infrared reflective pigment, and 2 or more types may be sufficient as it.
Specific examples of the infrared reflecting pigment include commercially available products such as “Daipyroxide (registered trademark) black # 9590” manufactured by Dainichi Seika Kogyo Co., Ltd., “Black 30C933” manufactured by Shepherd Color Japan, Asahi Kasei Kogyo Co., Ltd. “Black 6350” manufactured by the company, “Black 10C924” manufactured by Shepherd Color Japan, and the like.

  The content of the infrared reflective pigment may be appropriately set so as to exhibit a desired color, but is 15 parts by mass or more and 60 parts by mass with respect to 100 parts by mass of the synthetic resin (solid content) forming the resin layer. It is preferable that it is below, More preferably, it is 20 to 50 mass parts, More preferably, it is 25 to 40 mass parts. If the amount of the infrared reflecting pigment is too small, there is a possibility that a synthetic leather with a desired color cannot be obtained.

2.4. Other components In addition to the infrared reflective pigment, the resin layer may contain a colored pigment for toning. The color pigment for toning has an average reflectance of less than 20% at 780 to 1800 nm (near infrared region) or 400 to 760 nm (visible light region) with respect to the sample film produced by the above-mentioned film production method. If an average absorptivity becomes less than 70%, it will not restrict | limit in particular, A well-known pigment can be used. Preferably, a pigment having an average reflectance in the near-infrared region of 20% or more and an average absorption in the visible light region of less than 70% can easily suppress an increase in temperature under sunlight. When the color pigment for toning is also contained, it is preferable that the total content with the infrared reflective pigment is within the range of the content of the infrared reflective pigment.

  The resin layer may further contain known additives such as a flame retardant, an antioxidant, a lubricity-imparting agent, an ultraviolet absorber, and a leveling agent as long as the effects of the present invention are not impaired.

3. Outermost layer The outermost layer in the present invention contains hygroscopic fine particles together with the synthetic resin. By containing hygroscopic fine particles in both the resin layer and the outermost layer, a tactile sensation like smooth leather without stickiness can be sufficiently expressed.

  The thickness of the outermost layer is not particularly limited, but if it is too thin, there is a possibility that the color fading resistance may be lowered. Therefore, it is preferably 0.5 μm or more, more preferably 1 μm or more. On the other hand, if the thickness of the outermost layer is too thick, the bending resistance may be lowered. Therefore, the thickness is preferably 8 μm or less, more preferably 5 μm or less.

3.1. Synthetic resin For the synthetic resin constituting the outermost layer, see 2.1. This is the same as described above for the synthetic resin. The preferred resin as the synthetic resin constituting the outermost layer is the polyurethane resin. In particular, in order to improve the texture of the synthetic leather, a silicone-modified polycarbonate polyurethane resin (high slip urethane resin) is preferred.
In addition, the synthetic resin which comprises a resin layer, and the synthetic resin which comprises an outermost layer may use the same thing, and may use a different thing. For example, when importance is attached to the adhesion between the two layers, it is preferable that the synthetic resin constituting the resin layer and the synthetic resin constituting the outermost layer are the same, and the resin layer and the outermost layer are different from each other ( In the case of forming by a coating method), it is preferable to select a resin having processing characteristics suitable for each forming method according to the forming method of each layer.

3.2. Hygroscopic fine particles Except for the content of hygroscopic fine particles in the outermost layer, 2.2. This is the same as described above for the hygroscopic fine particles.
The hygroscopic fine particles in the resin layer and the hygroscopic fine particles in the outermost layer may be the same or different.

It is important that the content of the hygroscopic fine particles in the outermost layer is 0.2 g / m ² or more and 1 g / m ² or less. If the content of the hygroscopic fine particles in the outermost layer is less than the above range, stickiness is not sufficiently suppressed, and a tactile sensation like genuine leather cannot be obtained. Since the whitening property is deteriorated and the synthetic leather is whitened, a synthetic leather having a desired color (particularly black or dark) cannot be obtained. The content of the hygroscopic fine particles in the outermost layer is preferably 0.3 g / m ² or more and 0.9 g / m ² or less, more preferably 0.5 g / m ² or more and 0.8 g / m ^2. It is as follows. In the present invention, since the hygroscopic fine particles exist in both the outermost layer and the resin layer, even if the amount of the hygroscopic fine particles to be present in the outermost layer is very small as in the above range, the absorbed moisture remains. Since it is quickly transmitted to the base material layer through the hygroscopic fine particles in the resin layer, it is possible to sufficiently suppress the sticky feeling.

  The content of the hygroscopic fine particles in the resin layer and the content of the hygroscopic fine particles in the outermost layer is a mass ratio, and the value of the resin layer / outermost layer is preferably 1 or more and 100 or less, more preferably It is 2 or more and 50 or less, more preferably 35 or less, and particularly preferably 30 or less. If it is out of the range, the bending resistance or the whitening resistance may be lowered.

The total amount of the hygroscopic fine particles in the resin layer and the hygroscopic fine particles in the outermost layer is preferably 1.3 g / m ² or more and 21 g / m ² or less, more preferably 1.5 g / m ² or more, It is 16 g / m ² or less, more preferably 3 g / m ² or more and 10 g / m ² or less. In the present invention, even if the amount of the hygroscopic fine particles present in the outermost layer is very small as described above, it becomes possible to sufficiently suppress the stickiness, and as a result, the hygroscopicity contained in the synthetic leather. The total amount of fine particles can be reduced.

4). Manufacturing method The synthetic leather of this invention can be manufactured by joining between a base material layer and a resin layer, and joining between a resin layer and an outermost layer. The bonding method of each layer is not particularly limited. For example, each component constituting the resin layer or the outermost layer is liquefied with a solvent as necessary to prepare a coating solution, and after applying this, the solvent is removed by drying or the like. Or dry process such as reacting resin; laminating method in which a resin film is prepared using a coating solution containing each component constituting the resin layer or outermost layer, and this is applied; constituting the resin layer or outermost layer And a wet method in which a coating liquid obtained by liquefying each component is introduced into a coagulation bath and then solidified. In particular, the lamination method is preferably employed for the bonding between the base material layer and the resin layer, and the dry method is preferably employed for the bonding between the resin layer and the outermost layer.

There is no restriction | limiting in particular as a solvent in the case of employ | adopting the said dry method, What is necessary is just to select suitably from well-known solvents according to the kind etc. of synthetic resin to contain.
In the case of adopting the laminating method, a known adhesive can be used as an adhesive for adhering the resin film. For example, if the base material layer and the resin layer are joined, a polyurethane adhesive is used. Is preferable in terms of adhesive strength. Examples of the polyurethane-based adhesive include polyether-based, polyester-based, polycarbonate-based, or a composite type thereof. In any case, 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 of the present invention may be embossed or textured on the surface (outermost layer) as necessary. This makes it possible to obtain a desired appearance.

5. Properties of Synthetic Leather The basis weight of the synthetic leather of the present invention 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, it is 450 g / m < ² > or less. When the basis weight is within the above range, the synthetic leather is lightweight and excellent in mechanical properties.

  The thickness of the synthetic leather of the present invention is not particularly limited, but if it is too thin, durability during practical use may be insufficient, so 0.4 mm or more is preferable, and more preferably 0.5 mm or more. On the other hand, if the thickness of the synthetic leather is too thick, the handleability and lightness during post-processing may be impaired, so that it is preferably 4 mm or less, more preferably 3 mm or less.

  In a preferred embodiment of the synthetic leather of the present invention, when a friction test is performed with a load of 4.9 N using a Gakushin type friction tester with a dry cloth or sweat cloth attached to the friction element, in a gray scale for contamination specified in JIS-L0805. The number of frictions for maintaining the fourth grade is 500 times or more in the case of dry cloth, and 200 times or more in the case of sweat cloth. If the number of frictions for maintaining the fourth grade in the friction test is in the above range, sufficient fading resistance can be exhibited even when used for sheet materials and the like where repeated rubbing cannot be avoided. In the case of dry cloth, more preferably 800 times or more, still more preferably 1000 times or more, and in the case of sweat cloth, more preferably 250 times or more, further preferably 300 times or more. The method and evaluation of this friction test will be described in detail in Examples.

  In a preferred embodiment of the synthetic leather of the present invention, when light is irradiated from a distance of 90 cm using a 400 W metal halide lamp, the average surface temperature from 5 minutes to 10 minutes after the start of irradiation is less than 60 ° C. More preferably, it is 59 degrees C or less, More preferably, it is 58 degrees C or less. When the average surface temperature when irradiated with light under such specific conditions is within the above range, the surface can be touched by hand even when exposed to sunlight for a long time, but exceeds the above range. The surface becomes so hot that it cannot be touched by hand. The method for measuring the average surface temperature during light irradiation will be described in detail in Examples.

  In a preferred embodiment of the synthetic leather of the present invention, the increase (ΔH) of the palmar humidity after 1 minute of sweating in the sweat test by the sweat simulation apparatus is 20% RH or less. ΔH is more preferably 18% RH or less, further preferably 16% RH or less, and particularly preferably 15% RH or less. When the ΔH exceeds 20% RH, the sticky feeling becomes strong and the tactile feeling tends to be insufficient. The lower limit of ΔH is not particularly limited, but is 0% RH.

The sweating simulation device measurement is a model evaluation method that takes into consideration the practical environment in which constant water vapor and heat are always supplied to the interior material surface layer, and using a sweating simulation measurement device (manufactured by Toyobo Co., Ltd.), the amount of water supply: 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, The temperature and humidity of the space between the sample and the sample are measured.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. Of course, it is possible to implement them, and they are all included in the technical scope of the present invention.
The properties of the synthetic leather obtained in Examples and Comparative Examples were evaluated by the following methods.

<Fade resistance>
Using a Gakushin type friction testing machine (friction testing machine type II) described in JIS L0849 ("RT-300" manufactured by Daiei Kagaku Seisakusho Co., Ltd.), a friction piece (shape: R45 mm, size: 20 mm x 20 mm) A dry cloth (friction white cotton cloth (JIS L0803: cotton (for friction) No. 3-3)) or sweat cloth (a cloth in which artificial sweat liquid of the same mass as the dry cloth is immersed) A friction test is performed in which the friction element is reciprocated at 4.9 N, and the friction of the white cotton cloth for friction is shown in Table 1 below as shown in Table 1 below. In contrast to the gray scale, the number of frictions maintaining the fourth grade was evaluated. For example, if the number of frictions that have reached the third grade or lower for the first time is 200 times, the number of frictions for maintaining the fourth grade is 100 times. If dry cloth is used, the number of frictions is 1000 times, and if sweat cloth is used, the number of frictions is 300 times. If the class is grade 4 or 5, then “1000 times or more” or “300 times or more” is set. . When using dry cloth, if the number of frictions for maintaining the fourth grade is 500 times or more, when using sweat cloth, if the number of frictions for maintaining the fourth grade is 200 times or more, it has good fading resistance. I can say that.
The artificial sweat solution was prepared by adding 8 g of disodium phosphate (crystal), 8 g of sodium chloride and 5 g of acetic acid to 1 L of distilled water and dissolving them.

<Inside palm humidity rise (ΔH)>
Using a sweating simulation measuring device (manufactured by Toyobo Co., Ltd.), water supply amount: 140 g / m ² · hr, hot plate temperature: 37 ° C., sample-hot plate distance: 0.5 cm, environmental temperature and humidity: 20 ° C. × 65% RH, sweat pattern: A sweat test was conducted under the condition of sweating for 5 minutes from the start of the test, and the humidity in the space between the hot plate and the sample (the surface on the outermost layer side of the synthetic leather) was measured as the humidity in the palm. 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, 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.

<Stickiness>
The stickiness of the synthetic leather sample was determined by a paired comparison method using 10 monitors. That is, a 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, the left and right palms of the monitor were placed on the left and right samples on the car seat seat surface for 1 minute, and the stickiness after 1 minute was judged. Specifically, it is determined whether the left or right sample is more sticky, and after paired comparison judgment with all sample combinations, it is standardized by -2 to +2 points according to Thurston's paired comparison method, and scored The evaluation was based on the following criteria. In addition, it shows that it is not sticky, so that a score is high.
◎: 1.0 point or more ○: 0.5 point or more, less than 1.0 point Δ: 0 point or more, less than 0.5 point ×: less than 0 point

<Average surface temperature and thermal feeling>
Synthetic leather sample cut out to 11 cm in length × 15 cm in width is placed on a urethane pad 11 cm in length × 15 cm in width × 1 cm in thickness so that the base material layer of the synthetic leather sample is in contact with the urethane pad and warmed up for 30 minutes or more. Using a raised 400W metal halide lamp, irradiate light at a distance of 90 cm vertically from the sample surface for 10 minutes or more, measure the surface temperature of the center of the sample every 10 seconds from the start of irradiation, and start irradiation for 5 minutes. The average surface temperature from after to 10 minutes later was defined as the average surface temperature. And based on this average surface temperature, the thermal sensation was evaluated according to the following criteria.
◎: Less than 58 ° C ○: 58 ° C or more and less than 60 ° C Δ: 60 ° C or more and less than 62 ° C x: 62 ° C or more

<Whitening resistance>
A synthetic leather sample was penetrated with a leather sewing needle (14th / JIS B9012: 2000) from the surface (outermost layer side), and the degree of whitening around the needle hole was visually observed and judged according to the following criteria: .
○: Whitening is not recognized ×: Whitening is recognized

<Flexibility>
In accordance with JIS K6545, a bend resistance test was conducted on a synthetic leather sample using a bend resistance tester, and the presence or absence of cracks was confirmed every 10,000 times with one reciprocation. It was evaluated by the number of times that the crack was not generated). The test was conducted up to 100,000 times. If no crack occurred at that time, the test was set to “100,000 times or more”. If the number of times that the JIS 5 grade is maintained is 20,000 times or more, it can be said that the bending resistance is excellent.

Example 1
The resin layer forming composition prepared with the following composition was coated on a release paper with a comma coater (registered trademark) manufactured by Hirano Techseed Co., Ltd. and dried to prepare a resin layer film having a thickness of 35 μm.
[Composition for resin layer formation]
Urethane resin (“crisbon (registered trademark) NY-373” manufactured by DIC: 20 mass% solid content): 100 parts by mass • Infrared reflective pigment (“Black 10C924” manufactured by Shepherd Color Japan): 100 mass% solid content, Average reflectance 37% of wavelengths 780-1800 nm, average absorption 75% of wavelengths 400-760 nm): 7 parts by mass Toning pigment (“N-DYM8510 Green” manufactured by Dainichi Seika Kogyo Co., Ltd.): solid content 100% by mass , Average reflectance 14.5% at a wavelength of 780-1800 nm, average absorptance 80% at a wavelength of 400-760 nm): 1 part by mass Hygroscopic fine particles ("Tuffic (registered trademark) HU720SF" manufactured by Nippon Exlan Industries Co., Ltd.): Table Appropriately adjusted to the content described in 2. Solvent (dimethylformamide): 35 parts by mass

Next, an adhesive ("Rezamin (registered trademark) UD-8373" manufactured by Dainichi Seika Kogyo Co., Ltd.) is applied to the surface of the obtained resin layer film on the resin layer side using a comma coater (registered trademark) manufactured by Hirano Techseed Co., Ltd. at 160 g / A laminate of a base material layer and a resin layer was prepared by applying m ² , attaching a polyester tricot cloth as a base material layer to the coated surface, and performing an aging treatment (held at 60 ° C. for 24 hours).

Next, the release paper on the resin layer side of the obtained laminate is peeled off, and the outermost layer-forming composition prepared with the following blending composition is applied to this surface with a gravure coater so as to have a dry film thickness of 3 μm and dried. Synthetic leather was obtained. The properties of the obtained synthetic leather were as shown in Table 2.
[Composition for outermost layer formation]
Urethane resin ("Rezaroid (registered trademark) Lu889 (HM)" manufactured by Dainichi Seika Kogyo Co., Ltd .: solid content 18% by mass): 100 parts by mass-Hygroscopic fine particles ("Tuffic (registered trademark) HU720SF" manufactured by Nippon Exlan Industry Co. ): Adjusted so as to have the content shown in Table 2. Crosslinking agent (“Rezamin (registered trademark) NE-crosslinking agent” manufactured by Dainichi Seika Kogyo Co., Ltd .: solid content 75% by mass): 2 parts by mass

(Examples 2-5 and Comparative Examples 1-4)
Example 1 except that the amount of hygroscopic fine particles in the resin layer forming composition and the amount of hygroscopic fine particles in the outermost layer forming composition were changed to the contents shown in Table 2, respectively. Thus, a synthetic leather was obtained. The properties of the obtained synthetic leather were as shown in Table 2.

(Comparative Example 5)
Other than changing the amount of hygroscopic fine particles in the resin layer forming composition to the content shown in Table 2 and not providing the outermost layer (the laminate of the base material layer and the resin layer is a synthetic leather) Produced a synthetic leather in the same manner as in Example 1. The properties of the obtained synthetic leather were as shown in Table 2.

(Comparative Example 6)
The amount of hygroscopic fine particles in the resin layer forming composition and the amount of hygroscopic fine particles in the outermost layer forming composition are changed so as to have the contents shown in Table 2, respectively, and in the resin layer forming composition 7 parts by mass of the infrared reflective pigment and 1 part by mass of the toning pigment were added to a carbon black pigment (“Seika Seven (registered trademark) BS780 (S)” manufactured by Dainichi Seika Kogyo Co., Ltd.): solid content 30% by mass, wavelength 780 to Synthetic leather was obtained in the same manner as in Example 1 except that it was changed to 7 parts by mass (average reflectance 3% at 1800 nm). The properties of the obtained synthetic leather were as shown in Table 2.

(Comparative Example 7)
A synthetic leather was obtained in the same manner as in Comparative Example 6 except that the outermost layer was not provided (a laminate of the base material layer and the resin layer was a synthetic leather). The properties of the obtained synthetic leather were as shown in Table 2.

Claims (5)

A base material layer, a resin layer provided on the base material layer, and an outermost layer provided on the resin layer,
The synthetic leather, wherein the resin layer contains hygroscopic fine particles and an infrared reflecting pigment, and the outermost layer contains hygroscopic fine particles of 0.2 g / m ² or more and 1 g / m ² or less.   The synthetic leather according to claim 1, wherein the outermost layer contains a urethane resin.   When a friction test is performed with a load of 4.9 N using a Gakushin type friction tester with a dry cloth or sweat cloth on the friction element, the number of frictions to maintain the grade 4 in the gray scale for contamination specified in JIS-L0805 is The synthetic leather according to claim 1 or 2, which is 500 times or more in a case, and 200 times or more in the case of a sweat cloth.   The average surface temperature from 5 minutes to 10 minutes after the start of irradiation is less than 60 ° C when irradiated with light from a distance of 90 cm using a 400 W metal halide lamp. Synthetic leather as described.   The synthetic leather according to any one of claims 1 to 4, wherein in a sweat test using a sweat simulation apparatus, an increase (ΔH) in the palmar humidity after 1 minute of sweating is 20% RH or less.