Leather-like sheet

Abstract

To provide a leather-like sheet that is hard to be heated by solar radiation and has a colored resin layer in deeper black.SOLUTION: A leather-like sheet has a fiber base material and a colored resin layer stacked on the fiber base material. The colored resin layer contains polyurethane and 3 to 20 g / m2 of infrared reflecting black pigment having average dispersion particle size of 1 to 10 μm. The infrared reflecting black pigment has spectral reflectance of average 8% or less in the range of wave length of 650 to 780 nm and average 40% or more in the range of 780 to 2500 nm in the leather-like sheet.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a leather-like sheet having a dark colored resin layer. [Background technology]

[0002] A leather-like sheet comprising a fiber substrate and a grain-finish resin layer laminated on the fiber substrate is used as a material for bags, clothing, shoes, etc. The grain-finish resin layer is colored in various colors, but dark colors such as black are particularly widely used.

[0003] However, in recent years, due to the rise in temperature caused by global warming, there is a strong demand for measures against the summer heat. Generally, dark colors such as black tend to absorb infrared rays such as near-infrared rays, and are therefore easily heated by solar radiation. For this reason, it is desirable to make it difficult for leather-like sheets having a dark-colored resin layer to become heated by solar radiation.

[0004] Several such techniques have been proposed. For example, the following Patent Document 1 discloses a coating film comprising a base layer, a resin layer provided on the base layer, and an outermost layer provided on the resin layer, the resin layer containing hygroscopic fine particles and an infrared reflective pigment, and the outermost layer containing 0.2 g / m 2 More than 1g / m 2 This paper discloses a synthetic leather containing the following hygroscopic fine particles. This synthetic leather contains an infrared reflective pigment in the resin layer, so that even if it is black or a dark color, it does not heat up easily in sunlight, and has excellent resistance to fading because it has an outermost layer on the resin layer. This paper also discloses that the infrared reflective pigment has an average reflectance of 20% or more in the wavelength range of 780 to 1800 nm, and an average absorptance of 70% or more in the wavelength range of 400 to 760 nm.

[0005] Also, for example, Patent Document 2 listed below discloses a dark-colored sheet material having a resin layer on a sheet substrate, the resin layer containing a black pigment having an average absorptance of 30% or less in the wavelength region of 780 to 1800 nm, and an infrared reflective pigment having an average transmittance of 30% or more in the wavelength region of 380 to 780 nm and an average reflectance of 20% or more in the wavelength region of 780 to 1800 nm. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2015-168907 A [Patent Document 2] JP 2013-75366 A Summary of the Invention [Problem to be solved by the invention]

[0007] In the sheet material obtained by the above-mentioned conventional technology, by using an infrared reflective black pigment that easily reflects infrared rays, the resin layer that colors the surface can be colored a dark black color and can also be made less susceptible to heat generation due to solar radiation. However, when the resin layer is colored a dark black color using a conventional infrared reflective black pigment, the L * a * b * a, which is an index of redness in the color system * In addition, by using a resin layer in which a black pigment such as carbon black having a high blackness is used in combination with an infrared reflecting black pigment, it is possible to color the resin layer in a blackish deep color with a high blackness, but in this case, there is a problem that the carbon black absorbs infrared rays, thereby reducing the effect of blending the infrared reflecting black pigment in preventing heat absorption.

[0008] The present invention aims to solve such problems, that is, to provide a leather-like sheet having a colored resin layer of a deep black color with a high blackness that is less likely to become heated by solar radiation and is less likely to become reddish. [Means for solving the problem]

[0009] A common black pigment such as carbon black has a small average dispersed particle diameter, which increases the specific surface area, and the visible light absorption efficiency is increased, resulting in a black color with high blackness. Therefore, in the case of an infrared reflective black pigment, it is expected that the smaller the average dispersed particle diameter is, the higher the blackness will be. However, the inventors have noticed that the smaller the average dispersed particle diameter is in the infrared reflective black pigment, the more reddish the dark color is developed. The inventors have considered that, in the case of an infrared reflective black pigment, when the average dispersed particle diameter in the resin layer is too small and the specific surface area is large, the infrared reflective black pigment also slightly reflects red light and far-red light of 650 to 800 nm adjacent to the near infrared, resulting in a reddish dark color with reduced blackness. Based on such findings, the present invention has been conceived.

[0010] That is, one aspect of the present invention is a leather-like sheet comprising a fiber substrate and a colored resin layer laminated on the fiber substrate, the colored resin layer being made of polyurethane and a 3-20 g / m2 fiberglass fiber sheet having an average dispersed particle size of 1-10 μm. 2 and an infrared reflective black pigment, the infrared reflective black pigment having an average spectral reflectance of 8% or less in the wavelength range of 650 to 780 nm and an average spectral reflectance of 40% or more in the wavelength range of 780 to 2500 nm. Such a leather-like sheet is resistant to heat from solar radiation and has a low reflection coefficient of 100%. * a * b * a in color system *It is possible to provide a leather-like sheet having a dark colored resin layer with a low reflectivity and a low redness. The infrared reflective black pigment reflects infrared rays, but also slightly reflects red visible light and far-red light with wavelengths of about 650 to 780 nm adjacent to the infrared wavelength range. In the present invention, an infrared reflective black pigment having a specific spectral reflectance is used, and the average dispersed particle diameter is controlled to 1 to 10 μm, thereby reducing the reflection of red visible light and far-red light with wavelengths of about 650 to 780 nm when the infrared reflective black pigment reflects infrared rays, thereby obtaining a leather-like sheet having a dark black colored resin layer that is less likely to heat up due to solar radiation and has a high blackness. That is, by dispersing the infrared reflective black pigment with an average dispersed particle diameter of 1 to 10 μm, the specific surface area is appropriate, so that visible light and far-red light are sufficiently absorbed, and diffuse reflection due to the dispersed particle diameter being too large can be suppressed.

[0011] In addition, the leather-like sheet is L * a * b * In the color system, lightness L * Value ≦ 30, a * Having a surface with a value of L≦1 * a * b * a in color system * This is preferred from the viewpoint of producing deep colors such as blacks that have low color values ​​and are less likely to be reddish.

[0012] Furthermore, it is preferable that the leather-like sheet has an average solar reflectance of 30% or more in the wavelength range of 780 to 2500 nm, since this can adequately suppress temperature rise due to solar radiation.

[0013] In addition, the colored resin layer does not contain any pigment other than the infrared reflective black pigment, or does not contain any pigment other than the infrared reflective black pigment at a concentration of 0.3 g / m 2 It is preferable to include the black pigment in the range below, since this does not significantly impair the reflection of infrared rays by the infrared reflective black pigment. Effect of the Invention

[0014] According to the present invention, a leather-like sheet having a highly black, deep-colored resin layer that is resistant to heat generation due to solar radiation can be obtained. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is an explanatory diagram for explaining a method for measuring the surface temperature when the surface of the leather-like sheet used in the examples was irradiated with a white infrared heat lamp. [Diagram 2] FIG. 2 is a spectrum obtained by measuring the spectral reflectance of the infrared reflective black pigment used in the examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] An embodiment of the leather-like sheet according to the present invention will be described in detail. The leather-like sheet of this embodiment is a leather-like sheet comprising a fiber base material and a colored resin layer laminated on the fiber base material. The colored resin layer is made of polyurethane and a 3 to 20 g / m 2 The infrared reflective black pigment has an average dispersed particle size of 1 to 10 μm in the colored resin layer, and has a spectral reflectance of 8% or less in the wavelength range of 650 to 780 nm and 40% or more in the wavelength range of 780 to 2500 nm.

[0017] As the fiber substrate, there can be used, without any particular limitation, conventionally known artificial leather substrates used in the manufacture of artificial leathers, synthetic leather substrates used in the manufacture of synthetic leathers, such as nonwoven fabrics, woven fabrics, knitted fabrics, or substrates obtained by impregnating these with a polymeric elastomer such as polyurethane, etc.

[0018] The type of fiber forming the fiber base material is not particularly limited, and specific examples include nylon fibers, polyester fibers, polyolefin fibers, polyurethane fibers, and the like.

[0019] The fineness of the fibers forming the fiber substrate is not particularly limited, and may be, for example, a regular fiber having a fineness of more than 1 dtex or an ultrafine fiber having a fineness of less than 1 dtex. The form of the fibers is also not particularly limited, and may be a solid fiber or a fiber having voids such as a hollow fiber or a lotus root-shaped fiber.

[0020] The thickness of the fiber base material is not particularly limited, and may be, for example, about 0.3 to 3 mm, or about 0.5 to 1.5 mm.

[0021] The leather-like sheet of the present embodiment includes a colored resin layer laminated directly or indirectly to a fiber substrate. In this embodiment, "indirectly laminated" means that the colored resin layer in this embodiment is bonded via another resin layer such as an adhesive layer.

[0022] The colored resin layer is made of polyurethane and 3 to 20 g / m 2 The infrared reflective black pigment has an average dispersed particle size of 1 to 10 μm in the colored resin layer. The infrared reflective black pigment has a spectral reflectance of 8% or less on average in the wavelength range of 650 to 780 nm and 40% or more on average in the wavelength range of 780 to 2500 nm, as described below.

[0023] The infrared reflective black pigment is a black pigment that has a higher reflectance in the infrared region than ordinary pigments. The infrared reflective black pigment of this embodiment is a black pigment that has an average of 8% or less in the wavelength range of 650 to 780 nm and an average of 40% or more in the wavelength range of 780 to 2500 nm in the spectrum of spectral reflectance obtained by measuring a wavelength range of 400 to 2500 nm using a 6 mm thick film containing infrared reflective black pigment powder and polyurethane in a ratio of 50:50, and measuring the spectrum with a spectroscopic analyzer equipped with an integrating sphere. According to the above-mentioned measuring method, since the concentration of the infrared reflective black pigment in the film is sufficiently high, it is possible to measure the original spectrum of the infrared reflective black pigment's spectral reflectance that does not depend on the dispersed particle size.

[0024] The infrared reflective black pigment of this embodiment has a spectral reflectance of 8% or less, preferably 6% or less, on average, in the wavelength range of 650 to 780 nm, and 40% or more, preferably 50% or more, on average, in the wavelength range of 780 to 2500 nm. When the infrared reflective black pigment has a spectral reflectance of 8% or less on average in the wavelength range of 650 to 780 nm, a dark colored resin layer that is less likely to take on reddish color is formed. In addition, when the infrared reflective black pigment has a spectral reflectance of 40% or more on average in the wavelength range of 780 to 2500 nm, a colored resin layer that is less likely to take on heat due to solar radiation is formed.

[0025] Examples of such infrared reflective black pigments include Ca-Ti-Mn composite oxides, Cu-Bi composite oxides, and Fe-Cr composite oxides. A specific example of the infrared reflective black pigment of Ca-Ti-Mn composite oxides is Typek Black SG-101 manufactured by Ishihara Sangyo Kaisha, Ltd. A specific example of the infrared reflective black pigment of Cu-Bi composite oxides is Dipyroxide Black #9581 manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd. A specific example of the infrared reflective black pigment of Fe-Cr composite oxides is Dipyroxide Black #9596 manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd. Among these, the infrared reflective black pigment of Ca-Ti-Mn composite oxides and the infrared reflective black pigment of Cu-Bi composite oxides are preferred because they do not contain chromium, which imposes a burden on the environment.

[0026] The colored resin layer is a polyurethane-based resin with the above-mentioned infrared reflective black pigment at 3 to 20 g / m 2 The infrared reflective black pigment is dispersed in the resin, and the average dispersed particle size of the infrared reflective black pigment is 1 to 10 μm. The term "mainly composed of polyurethane" means that 50% by mass or more, further 70% by mass or more, particularly 90% by mass or more, and even more particularly 100% by mass of the resin is polyurethane. The resin other than polyurethane is not particularly limited.

[0027] The polyurethane contained in the colored resin layer is obtained by reacting urethane raw materials including a polymer polyol, an organic polyisocyanate, and a chain extender. Polyurethane is prepared as an organic solvent solution containing, for example, N,N-dimethylformamide (DMF), methyl ethyl ketone (MEK), acetone, toluene, or the like as a solvent, an aqueous dispersion such as an emulsion, or a melt.

[0028] Specific examples of polymer polyols include polyether polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and polymethyltetramethylene glycol; polycarbonate polyols such as polyhexamethylene carbonate diol, poly(3-methyl-1,5-pentylene carbonate) diol, polypentamethylene carbonate diol, and polytetramethylene carbonate diol; polyester polyols such as polyethylene adipate diol, polybutylene adipate diol, polypropylene adipate diol, polybutylene sebacate diol, polyhexamethylene adipate diol, poly(3-methyl-1,5-pentylene adipate) diol, poly(3-methyl-1,5-pentylene sebacate) diol, and polycaprolactone diol, or copolymers thereof. These may be used alone or in combination of two or more.

[0029] Specific examples of organic polyisocyanates include diisocyanates that are difficult to yellow, such as aromatic diisocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylene diisocyanate; and non-yellowing diisocyanates such as aliphatic or alicyclic diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate. These may be used alone or in combination of two or more. Also, polyfunctional isocyanates such as trifunctional isocyanates and tetrafunctional isocyanates may be used in combination, if necessary.

[0030] Specific examples of the chain extender include diamines such as hydrazine, ethylenediamine, propylenediamine, hexamethylenediamine, nonamethylenediamine, xylylenediamine, isophoronediamine, piperazine and its derivatives, adipic acid dihydrazide, and isophthalic acid dihydrazide; triamines such as diethylenetriamine; tetramines such as triethylenetetramine; diols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-bis(β-hydroxyethoxy)benzene, and 1,4-cyclohexanediol; triols such as trimethylolpropane; pentaols such as pentaerythritol; aminoalcohols such as aminoethyl alcohol and aminopropyl alcohol. These may be used alone or in combination of two or more. During the chain extension reaction, monoamines such as ethylamine, propylamine, and butylamine; carboxyl group-containing monoamine compounds such as 4-aminobutanoic acid and 6-aminohexanoic acid; and monools such as methanol, ethanol, propanol, and butanol may be used in combination with the chain extender.

[0031] For example, when an organic solvent solution of polyurethane is used, an infrared reflective black pigment dispersion is prepared by dispersing an infrared reflective black pigment in an organic solvent solution of polyurethane, and the dispersion is applied to a release paper in a predetermined thickness and then dried to form a polyurethane film for forming the colored resin layer.

[0032] Such an infrared reflective black pigment dispersion is prepared, for example, by mixing an organic solvent solution of polyurethane with an infrared reflective black pigment, and adjusting the dispersion state of the infrared reflective black pigment as described below using a dispersing machine such as a bead mill or a ball mill. For example, in the case of dispersion treatment using a ball mill, the conditions are not particularly limited, and are appropriately adjusted depending on the concentration of the polyurethane and the infrared reflective black pigment, and the diameter and type of the dispersion media such as glass beads. In addition, it is preferable to perform the dispersion treatment for about 10 to 30 minutes until a predetermined dispersion state is achieved. In addition, after preparing the dispersion state of the infrared reflective black pigment, an organic solvent solution of polyurethane may be mixed as necessary to further adjust the concentration of the infrared reflective black pigment.

[0033] The colored resin layer of the present embodiment may be a layer having a homogeneous composition, or may be a laminate of a plurality of colored resin layers having different compositions in terms of the types and blending ratios of polyurethane or infrared reflective black pigment, or may be a layer having a homogeneous composition, the layer being made up of a surface layer, an intermediate layer, or the like.

[0034] The colored resin layer of this embodiment has a thickness of 3 to 20 g / m 2 , preferably 5 to 15 g / m 2 The content of the infrared reflective black pigment in the colored resin layer is 3 g / m 2 If the content of the infrared reflective black pigment in the colored resin layer is less than 20 g / m, the reflectance to infrared rays decreases, and the temperature rise due to solar radiation cannot be sufficiently suppressed. 2 If it exceeds this value, the wear resistance decreases.

[0035] The colored resin layer contains infrared reflective black pigment at 3 to 20 g / m 2 As long as the infrared reflective black pigment is contained, its thickness is not particularly limited, but it is preferably 10 to 80 μm, and more preferably 20 to 70 μm. If the colored resin layer is too thin, the infrared reflective black pigment is added to 3 g / m 2 It tends to be difficult to incorporate more than this amount.

[0036] The content of the infrared reflective black pigment in the colored resin layer is 3 to 20 g / m 2 The content is not particularly limited as long as it is contained, but it is preferably 5 to 40 mass %, and more preferably 10 to 30 mass %. If the content of the infrared reflective black pigment is too low, the infrared reflective black pigment is increased to 3 g / m 2 If the content is too high, mechanical properties such as wear resistance and bending resistance tend to decrease.

[0037] In this embodiment, the infrared reflective black pigment is dispersed in the colored resin layer so as to have an average dispersed particle diameter of 1 to 10 μm, preferably 1.5 to 8 μm. By having the average dispersed particle diameter of the infrared reflective black pigment in this range, diffuse reflection of light on the surface of the infrared reflective black pigment particles is suppressed, making it easier to form a colored resin layer with a deep black color with high blackness.

[0038] When the average particle size of the infrared reflective black pigment dispersed in the colored resin layer is less than 1 μm, the surface of the infrared reflective black pigment particles tends to diffusely reflect light, resulting in increased reflection of red light and far-red light in the range of 650 to 780 nm, and the colored resin layer tends to be formed with a low degree of blackness due to the strong redness. When the average particle size of the infrared reflective black pigment exceeds 10 μm, the specific surface area of ​​the infrared reflective black pigment becomes too small to absorb visible light sufficiently, and the colored resin layer tends to be formed with a low degree of blackness. In addition, the mechanical properties of the film of the colored resin layer are reduced, resulting in a decrease in abrasion resistance.

[0039] The colored resin layer does not contain any pigment other than the infrared reflective black pigment described above, or the content of the pigment other than the infrared reflective black pigment is 0.3 g / m2 or less, depending on the type of pigment. 2 The colored resin layer preferably contains a pigment other than an infrared reflective black pigment in an amount of 0.3 g / m 2 If the content exceeds this range, pigments other than the infrared reflective black pigment may preferentially absorb infrared light, which tends to reduce the reflectance to infrared light and makes it difficult to suppress a rise in temperature due to solar radiation.

[0040] In addition, when the colored resin layer contains a pigment other than the infrared reflective black pigment, the pigment is not particularly limited as long as it does not have too high an absorption efficiency of near infrared rays in the wavelength range of 780 to 2500 nm. Specific examples of the pigment include anthraquinone pigments, diketopyrrolopyrrole pigments, and perylene pigments such as perylene black.

[0041] The leather-like sheet of this embodiment is a leather-like sheet comprising a fiber substrate and a colored resin layer laminated on the fiber substrate. It may also comprise layers other than the colored resin layer, such as an adhesive layer. As long as it does not impair the effects of the present invention, it may also comprise a clear layer, which is an uncolored resin layer and has a thickness of about 1 to 10 μm, on the surface of the colored resin layer, as necessary.

[0042] In order to form a colored resin layer on the surface of a fiber base material, for example, the following dry surface forming method can be used.

[0043] An adhesive is applied to the colored resin layer formed on the release paper, and the solvent is completely or incompletely removed and dried. Then, the adhesive laminated on the colored resin layer formed on the release paper is attached to the surface of the fiber substrate and pressed, and the adhesive is cured to bond the fiber substrate and the colored resin layer via the adhesive layer. Then, the release paper is peeled off from the surface of the colored resin layer to obtain a leather-like sheet having the fiber substrate and the colored resin layer laminated on the fiber substrate.

[0044] The leather-like sheet of the present embodiment thus obtained has a colored resin layer containing the infrared reflective black pigment as described above, and thus has a characteristic of being L * a * b * In the color system, lightness L * Value ≦ 30, a * It is preferred to have surfaces with a value ≦1.

[0045] In addition, L * a * b * In the color system, lightness L * Value ≦ 30, a *The term "having a surface with a value of ≦1" means that the L * a * b * The lightness calculated from the coordinate values ​​of the color system is L * value ≦30, and the chromaticity index a * The value is a * It means that the value is ≦ 1. Lightness L * The value is L * Value ≦30, and furthermore, L * It is preferable that the chromaticity index a is ≦25 in terms of high color intensity. * The value is a * Value ≦ 1, even a * A value of ≦0.7 is preferred since it results in a deep black color with low redness and high blackness.

[0046] The leather-like sheet of this embodiment is provided with a colored resin layer containing the infrared-reflecting black pigment as described above, and thus a leather-like sheet is obtained that is less susceptible to heat absorption by solar radiation and has a colored resin layer of a dark color such as a black color with a high degree of blackness.

[0047] The leather-like sheet of the present embodiment described above is preferably used as a grain-finished leather-like sheet that resembles natural leather and is used as a skin material for bags, clothing, shoes, etc. In particular, when used as a material for bags, clothing, or shoes that cover the body, it is possible to prevent them from becoming too hot. EXAMPLES

[0048] The present invention will be described in more detail below with reference to examples, although the scope of the present invention is not limited to these examples in any way.

[0049] First, the evaluation methods used in the present examples will be summarized. (Average dispersed particle size of black pigment) Using a scanning electron microscope (JSM-IT500 manufactured by JEOL Ltd.), a 2000x SEM photograph of the cross section in the thickness direction of the colored resin layer of the test piece cut out from the leather-like sheet was taken. 2 The particle diameters Rn of n particles of all black pigments observed within the range were measured. The longest part of the observed black pigment was taken as the particle diameter. In addition, when multiple particles aggregate to form secondary particles, the longest part of the secondary particle was taken as the particle diameter. In addition, when there were multiple types of particles within the SEM photographing range, a qualitative analysis was performed in advance by EDS elemental analysis within the SEM photographing range to identify the black pigments to be the subject of particle diameter measurement.

[0050] Then, the volume Vn of each of the n particles was calculated from the particle diameter Rn obtained using the following formula: Note that each volume Vn was calculated assuming that the particle was spherical.

[0051] Volume of black pigment particles Vn = 4 / 3 × π × (Rn / 2) 3 The n volumes Vn obtained were arranged in ascending order of particle diameter Rn, and the cumulative sum was calculated to obtain the volume cumulative frequency. The particle diameter at which the volume cumulative frequency was 50% was determined as the dispersed particle diameter (D 50 The above measurements were carried out at five arbitrary points on the leather-like sheet, and the dispersed particle diameters (D 50 ) was taken as the average dispersed particle size.

[0052] (Average reflectance of infrared reflective black pigment) 30 parts by mass of infrared reflective black pigment powder, 100 parts by mass of a polyether polyurethane solution with a solid content of 30% by mass (Rezamin ME-8116 manufactured by Dainichi Seikagaku Kogyo Co., Ltd.), and 50 parts by mass of DMF were put into a cylindrical sealed container together with a dispersion medium (glass beads φ1.5 mm). Then, the cylindrical sealed container was set in a test disperser manufactured by Toyo Seiki Seisakusho Co., Ltd., and a dispersion treatment was performed for 5 minutes. In this way, an infrared reflective black pigment dispersion liquid containing infrared reflective black pigment and polyether polyurethane in a ratio of 50:50 was prepared. Then, the infrared reflective black pigment dispersion liquid was applied to white paper using a 6 mil applicator, and dried for 10 minutes in a hot air dryer at 90°C to form an evaluation film. As the white paper, the white part of a hiding ratio test paper having a white part and a black part as specified in 4.1.2 [Method B (hiding ratio test paper)] of JIS K 5600-4-1:1999 was used.

[0053] Then, a spectrophotometer was used to measure the reflectance of the surface of the evaluation film in the wavelength range of 400 to 2500 nm, thereby obtaining a spectrum of the spectral reflectance. As the spectrophotometer, a V-770 spectrophotometer equipped with an ISN-923 integrating sphere manufactured by JASCO Corporation was used. From the spectrum of the spectral reflectance, the average of the spectral reflectance in each of the ranges of 650 to 780 nm and 780 to 2500 nm was calculated.

[0054] In addition, polyether polyurethane was used as a binder to prepare the evaluation film, and in the average value of the spectral reflectance measured as described above, the light absorption by the polyether polyurethane is substantially negligible.

[0055] (L * Value and a * (measurement of value) The reflectance spectrum of the surface of the leather-like sheet was measured using a spectrophotometer. The spectrophotometer used was a U-3010 manufactured by Hitachi High-Technologies Corporation. From the obtained reflectance spectrum, the L * a* b * The coordinate values ​​of the color system were calculated. Three average positions were selected evenly from the test piece, and the reflectance spectrum was measured. * Value and a * The values ​​were averaged.

[0056] (Solar reflectance) A spectrophotometer was used to measure the reflectance of the surface of the leather-like sheet in the wavelength range of 780 to 2500 nm, to obtain a spectrum of the spectral reflectance. The spectrophotometer used was a V-770 spectrophotometer equipped with an ISN-923 integrating sphere manufactured by JASCO Corporation. The average of the spectral reflectance in the wavelength ranges of 650 to 780 nm and 780 to 2500 nm was calculated as the solar reflectance.

[0057] (Surface temperature when irradiated with a white infrared heat lamp) The surface temperature during irradiation with a white infrared heat lamp was measured using a device conforming to ASTM D 4803-97. Specifically, the measurement was performed as follows. In a room adjusted to an atmospheric temperature of 23.9 ± 2.8 ° C., a surface temperature measurement box 10 was prepared in which a white hard calcium silicate hydrate plate 2 having a thickness of 25.4 mm was provided on the inner wall of a wooden housing 1 with the top and front open as shown in FIG. 1. Then, at a position 152 ± 25 mm from the inner wall of the surface temperature measurement box 10 and an equal distance from both side walls, the surface of the colored resin layer side was placed facing up so that the center of the leather-like sheet test piece 4 cut into a 76 × 76 mm square was located. Then, a 250 W white infrared heat lamp 3 was placed at a height of 394 ± 25 mm from the center position of the test piece. Then, the white infrared heat lamp 3 was turned on to irradiate light, and the surface temperature of the test piece 20 minutes after the start of irradiation was measured using a non-contact thermometer.

[0058] (Wear resistance: Taber abrasion) A test piece of the leather-like sheet cut into a circle with a diameter of 13 cm was set on the turntable of a Taber Abrasion Tester (manufactured by Taber Instrument Corp.) with the colored resin layer side facing up. The colored resin layer side was abraded 1000 times at 60 rpm with two abrasion wheels (H-22 (manufactured by Daito Electron Co., Ltd.)). The load was set at 500 g. The change in the surface condition of the test piece of the leather-like sheet was evaluated according to the following criteria. Grade 5: No change in appearance observed Grade 4: Changes in gloss and scratches were observed on the surface of the colored resin layer, but the adhesive layer was not exposed. Grade 3: Part of the colored resin layer was worn away, and less than 10% of the adhesive layer or fiber base material was exposed. Grade 2: Part of the colored resin layer was worn away, and the adhesive layer or fiber base material was exposed over a range of 10% to less than 50%. Grade 1: Part of the colored resin layer has worn away, exposing 50% or more of the adhesive layer or fiber base material.

[0059] The production of the fiber base material used in this example will be described below. (Manufacturing of fiber base material) A melt conjugate spinning die was used, which was designed to use a water-soluble thermoplastic polyvinyl alcohol as the sea component, a PET modified with 6 mol% isophthalic acid as the island component, 25 islands per fiber, and a sea component / island component ratio of 25 / 75 (mass ratio), and islands-in-sea type conjugate fiber filaments were extruded from the die at 260° C. Then, the ejector pressure was adjusted so that the spinning speed was 4000 m / min, and islands-in-sea type conjugate fibers with an average fineness of 2.5 dtex were collected on a net, resulting in a weight per unit area of ​​30 g / m. 2 Thus, a web of long fibers was obtained.

[0060] The web was then cross-wrapped to pile up 12 layers, which were then sprayed with a needle breakage prevention oil. Then, the web was cut with a 6-barb needle to achieve 2000 punches / cm. 2 An entangled web was obtained by needle punching at a punch density of 0.1 mm.

[0061] The entangled web was then heat-shrunk by steam. Specifically, first, 30% by mass of moisture based on the mass of the sea component was added to the entangled web, and then the web was heat-treated for 80 seconds in a heated steam atmosphere at a relative humidity of 90% and a temperature of 110° C. The area shrinkage rate at this time was 45%.

[0062] Next, the heat-shrunk web was impregnated with a dispersion of an anionic self-emulsifying aqueous polyurethane (100% modulus 3.0 MPa). The concentration of the aqueous polyurethane dispersion was such that the mass ratio of the aqueous polyurethane to the island component was 10 / 90. The aqueous polyurethane dispersion was gelled in a water vapor atmosphere to prevent migration, and then dried at 120°C for 10 minutes.

[0063] The web impregnated with the aqueous polyurethane was then immersed in hot water at 95°C for 30 minutes to remove the sea component and form ultrafine fibers, which were then dried at a temperature of 120°C for 10 minutes to obtain a 2.1 mm thick fiber substrate containing a nonwoven fabric of 0.1 dtex ultrafine fibers. The 2.1 mm thick fiber substrate was then sliced ​​along a plane approximately parallel to its surface to obtain a 1.0 mm thick fiber substrate containing a nonwoven fabric of 0.1 dtex ultrafine fibers, with a basis weight of 530 g / cm. 3 Thus, a fiber substrate of 100 g was obtained.

[0064] The infrared reflective black pigments used in this example are summarized below: Figure 2 shows the spectra obtained by measuring the spectral reflectance of each infrared reflective black pigment. Infrared reflective black pigment made of Ca-Ti-Mn composite oxide: Typec Black SG-101 manufactured by Ishihara Sangyo Kaisha, Ltd., which has an average spectral reflectance of 4.9% in the wavelength range of 650 to 780 nm and 56.0% in the wavelength range of 780 to 2500 nm. Infrared reflective black pigment of Cu-Bi composite oxide: Dipyroxide Black #9581 manufactured by Dainichi Seika Chemicals Co., Ltd., which has an average spectral reflectance of 5.1% in the wavelength range of 650 to 780 nm and 57.2% in the wavelength range of 780 to 2500 nm. Infrared reflective black pigment of Fe-Co-Cr composite oxide: Dipyroxide Black #9590 manufactured by Dainichi Seika Chemicals Co., Ltd., which has an average spectral reflectance of 4.2% in the wavelength range of 650 to 780 nm and 26.5% in the wavelength range of 780 to 2500 nm. Infrared reflective black pigment made of Ni-Fe composite oxide: Black 10C924 manufactured by Shepherd Color Japan Co., Ltd., which has an average spectral reflectance of 10.7% in the wavelength range of 650 to 780 nm and 48.7% in the wavelength range of 780 to 2500 nm. [Example 1] 50 parts by mass of infrared reflective black pigment of Ca-Ti-Mn composite oxide, 15 parts by mass of a solution containing polyether polyurethane with a solid content of 30% by mass (PEt-based PU solution), and 35 parts by mass of DMF were put into a cylindrical sealed container together with a dispersion medium (glass beads φ1.5 mm). Then, the mixture was dispersed for 10 minutes using a test disperser manufactured by Toyo Seiki Seisakusho Co., Ltd., to prepare an infrared reflective black pigment dispersion. The PEt-based PU solution used was Resamine ME-8116 manufactured by Dainichi Seikagaku Kogyo Co., Ltd.

[0065] Then, 10 parts by mass of the infrared reflective black pigment dispersion, 100 parts by mass of the PEt-based PU solution, 30 parts by mass of DMF, and 10 parts by mass of MEK were mixed together to prepare a composition for a colored resin layer.

[0066] Then, the colored resin layer composition was applied onto the release paper in a wet coating amount of 130 g / m so that the thickness after drying would be 30 μm. 2 A surface layer was formed by applying the same colored resin layer composition to the surface of the surface layer formed on the release paper, and drying the composition at 120° C. for 2 minutes. An intermediate layer was formed by applying the same colored resin layer composition to a dry thickness of 30 μm on the surface of the surface layer formed on the release paper, and drying the composition at 120° C. for 2 minutes. As the release paper, EV130TPDR-8 manufactured by Lintec Corporation was used.

[0067] In this way, polyurethane and 12 g / m 2 and an infrared reflective black pigment, was formed to a thickness of 60 μm.

[0068] Meanwhile, a polyurethane solution for forming an adhesive layer was prepared by mixing 100 parts by mass of a polyether-based polyurethane solution with a solid content of 60% by mass (Rezamin UD-8310NTT manufactured by Dainichi Seikagaku Kogyo Co., Ltd.), 10 parts by mass of an isocyanate crosslinking agent (NE crosslinking agent manufactured by Dainichi Seikagaku Kogyo Co., Ltd.), 2 parts by mass of a crosslinking accelerator (UD-103 accelerator manufactured by Dainichi Seikagaku Kogyo Co., Ltd.), 30 parts by mass of DMF, and 20 parts by mass of MEK.

[0069] Then, a polyurethane solution for forming an adhesive layer was wet-coated on the surface of the colored resin layer formed on the release paper in an amount of 150 g / m 2 The adhesive was applied to the surface of a fiber substrate in a semi-dried state, and then dried for 5 minutes at 130°C. In order to promote the crosslinking reaction of the adhesive layer, the adhesive was heated for 48 hours in a dryer at an atmospheric temperature of 60°C. The release paper was then peeled off to obtain a leather-like sheet, which is an artificial leather.

[0070] The properties of the resulting leather-like sheet were evaluated by the following methods. The evaluation results are shown in Table 1.

[0071] [Table 1]

[0072] [Example 2] A colored resin layer composition was prepared in the same manner as in Example 1, except that 2.3 parts by mass of the infrared reflective black pigment dispersion was mixed instead of 10 parts by mass of the infrared reflective black pigment dispersion. 2 A leather-like sheet was obtained and evaluated in the same manner as in Example 1, except that a colored resin layer having a thickness of 60 μm containing the infrared reflective black pigment was formed. The results are shown in Table 1. [Example 3] A colored resin layer composition was prepared in the same manner as in Example 1, except that 17 parts by mass of the infrared reflective black pigment dispersion was mixed instead of 10 parts by mass of the infrared reflective black pigment dispersion. 2 A leather-like sheet was obtained and evaluated in the same manner as in Example 1, except that a colored resin layer having a thickness of 60 μm containing the infrared reflective black pigment was formed. The results are shown in Table 1. [Example 4] A leather-like sheet was obtained and evaluated in the same manner as in Example 1, except that the dispersion treatment time for preparing the infrared reflective black pigment dispersion was changed from 10 minutes to 20 minutes. The results are shown in Table 1. [Example 5] A leather-like sheet was obtained and evaluated in the same manner as in Example 1, except that the dispersion treatment time for preparing the infrared reflective black pigment dispersion was changed from 10 minutes to 5 minutes. The results are shown in Table 1. [Example 6] A colored resin layer composition was prepared in the same manner as in Example 1, except that 0.38 parts by mass of a perylene black dispersion was further mixed.

[0073] The perylene black dispersion was prepared by the following method. 20 parts by mass of perylene black (Paliogen Black S0084, manufactured by BASF), 15 parts by mass of a solution containing polyether-based polyurethane with a solid content of 30% by mass (PEt-based PU solution), and 35 parts by mass of DMF were charged into a cylindrical sealed container together with a dispersion medium (glass beads φ1.5 mm). Then, the mixture was dispersed for 30 minutes using a test disperser manufactured by Toyo Seiki Seisakusho Co., Ltd., to prepare a perylene black dispersion. The PEt-based PU solution used was Resamine ME-8116 manufactured by Dainichi Seiki Color & Chemicals Co., Ltd.

[0074] In this way, polyurethane and 12.0 g / m 2 of infrared reflective black pigment and 0.2 g / m 2 A leather-like sheet was obtained and evaluated in the same manner as in Example 1, except that a colored resin layer containing 100% perylene black and 100% perylene black was formed to a thickness of 60 μm. The results are shown in Table 1. [Example 7] A composition for a colored resin layer was prepared in the same manner as in Example 1, except that 0.75 parts by mass of a perylene black dispersion was further mixed. 2 of infrared reflective black pigment and 0.4 g / m 2 A leather-like sheet was obtained and evaluated in the same manner as in Example 1, except that a colored resin layer containing 100% perylene black and 100% perylene black was formed to a thickness of 60 μm. The results are shown in Table 1. [Example 8] In Example 1, to prepare a colored resin layer composition for an intermediate layer, 1.3 parts by mass of a carbon black dispersion (Seika Seven DUT-4794, manufactured by Dainichi Seika Chemicals Mfg. Co., Ltd., solid content 24%) was added instead of the infrared reflective black pigment dispersion, and the infrared reflective black pigment content in the colored resin layer was 6.0 g / m 2 and carbon black content of 0.5 g / m 2 Except for adjusting the hue by using the above-mentioned method, an artificial leather was obtained and evaluated in the same manner as in Example 1. The results are shown in Table 2. [Example 9] In Example 1, 21 parts by mass of carbon black dispersion was added to the colored resin layer composition for the intermediate layer instead of the infrared reflective black pigment dispersion, and the infrared reflective black pigment content in the colored resin layer was 12 g / m 2 and carbon black content of 6.0 g / m 2 Except for adjusting the hue by using the above-mentioned method, an artificial leather was obtained and evaluated in the same manner as in Example 1. The results are shown in Table 2. [Example 10] An artificial leather was obtained and evaluated in the same manner as in Example 1, except that the infrared reflective black pigment was not mixed into the colored resin layer composition for the intermediate layer in Example 1. The results are shown in Table 1. [Example 11] A leather-like sheet was obtained and evaluated in the same manner as in Example 1, except that an infrared reflective black pigment of Cu-Bi composite oxide was used instead of the infrared reflective black pigment of Ca-Ti-Mn composite oxide in Example 1. The results are shown in Table 1. [Comparative Example 1] A colored resin layer composition was prepared in the same manner as in Example 1, except that 1.5 parts by mass of the infrared reflective black pigment dispersion was mixed instead of 10 parts by mass of the infrared reflective black pigment dispersion. 2 A leather-like sheet was obtained and evaluated in the same manner as in Example 1, except that a colored resin layer having a thickness of 60 μm containing the infrared reflective black pigment was formed. The results are shown in Table 2.

[0075] [Table 2]

[0076] [Comparative Example 2] A colored resin layer composition was prepared in the same manner as in Example 1, except that 25.0 parts by mass of the infrared reflective black pigment dispersion was mixed instead of 10 parts by mass of the infrared reflective black pigment dispersion. 2 A leather-like sheet was obtained and evaluated in the same manner as in Example 1, except that a colored resin layer having a thickness of 60 μm containing the infrared reflective black pigment was formed. The results are shown in Table 2. [Comparative Example 3] A leather-like sheet was obtained and evaluated in the same manner as in Example 1, except that the dispersion treatment time for preparing the infrared reflective black pigment dispersion was changed from 10 minutes to 40 minutes. The results are shown in Table 2. [Comparative Example 4] An artificial leather was obtained and evaluated in the same manner as in Example 1, except that no dispersing media was used when preparing the infrared reflective black pigment dispersion liquid and the dispersion treatment time was changed to 5 minutes. The results are shown in Table 2. [Comparative Example 5] In Example 11, except that the dispersion treatment time for preparing the infrared reflective black pigment dispersion was changed from 10 minutes to 40 minutes, a leather-like sheet was obtained and evaluated in the same manner as in Example 1. The results are shown in Table 2. [Comparative Example 6] A leather-like sheet was obtained and evaluated in the same manner as in Example 1, except that an infrared reflective black pigment of Fe-Co-Cr composite oxide was used instead of the infrared reflective black pigment of Ca-Ti-Mn composite oxide in Example 1. The results are shown in Table 2. [Comparative Example 7] A leather-like sheet was obtained and evaluated in the same manner as in Example 1, except that an infrared reflective black pigment of Ni-Fe composite oxide was used instead of the infrared reflective black pigment of Ca-Ti-Mn composite oxide in Example 1. The results are shown in Table 2. [Comparative Example 8] A colored resin layer composition was prepared in the same manner as in Example 7, except that 1.3 parts by mass of a phthalocyanine green dispersion was further mixed.

[0077] The phthalocyanine green dispersion was prepared by the following method. 20 parts by mass of phthalocyanine green (N-DYM8510 Green, manufactured by Dainichi Seiki Chemicals Mfg. Co., Ltd., solid content 100%), 15 parts by mass of a solution containing polyether-based polyurethane with a solid content of 30% by mass (PEt-based PU solution), and 35 parts by mass of DMF were charged into a cylindrical sealed container together with a dispersion medium (glass beads φ1.5 mm). Then, the mixture was dispersed for 30 minutes using a test disperser manufactured by Toyo Seiki Mfg. Co., Ltd. to prepare a phthalocyanine green dispersion. The PEt-based PU solution used was Resamine ME-8116 manufactured by Dainichi Seiki Chemicals Mfg. Co., Ltd.

[0078] In this way, polyurethane and 12.0 g / m 2 of infrared reflective black pigment and 0.6 g / m 2 A leather-like sheet was obtained and evaluated in the same manner as in Example 1, except that a colored resin layer containing phthalocyanine green and having a thickness of 60 μm was formed. The results are shown in Table 1. [Comparative Example 9] In Example 1, a carbon black dispersion (Seika Seven DUT-4794, manufactured by Dainichi Seika Chemicals Mfg. Co., Ltd., solid content 24%) was used instead of the infrared reflective black pigment in the surface layer, and the carbon black content was 12.0 g / m 2A leather-like sheet was obtained and evaluated in the same manner as in Example 1, except that the colored resin layer was formed as described above. The results are shown in Table 2.

[0079] Referring to Table 1, the colored resin layer is composed of polyurethane and 3 to 20 g / m 2 The leather-like sheets obtained in Examples 1 to 11 each contain an infrared reflective black pigment having an average dispersed particle size of 1 to 10 μm and a spectral reflectance of 8% or less in the wavelength range of 650 to 780 nm and 40% or more in the wavelength range of 780 to 2500 nm. * Value ≦ 30 and a * The leather-like sheet developed a deep black color with little redness (value ≦1), and the surface temperature did not increase easily when irradiated with a white infrared heat lamp simulating solar radiation, and it also had excellent abrasion resistance.

[0080] On the other hand, the colored resin layer is 3 g / m 2 The leather-like sheet obtained in Comparative Example 1, which does not contain the above infrared reflective black pigment, is L * A deep color such as a value of ≦30 could not be obtained, and the surface temperature was easily raised when irradiated with a white infrared heat lamp. 2 The leather-like sheet obtained in Comparative Example 2, which contained an infrared reflective black pigment exceeding 1 μm, was extremely poor in abrasion resistance. * A value of ≧1 indicates a strong reddish color with a low blackness.

[0081] In addition, the leather-like sheet obtained in Comparative Example 4, in which the average dispersed particle diameter of the infrared reflective black pigment in the colored resin layer exceeded 10 μm, was less likely to have a high surface temperature when irradiated with a white infrared heat lamp. * The leather-like sheet had a low blackness of ≥30 and was also poor in abrasion resistance.

[0082] In addition, the leather-like sheet obtained in Comparative Example 7, which used an infrared reflective black pigment with an average spectral reflectance of more than 8% in the wavelength range of 650 to 780 nm, *In order to reduce the redness of the leather-like sheet obtained in Comparative Example 7, phthalocyanine green was further mixed to obtain a * The leather-like sheet obtained in Comparative Example 8, in which the hue was adjusted to have a value of ≦1, did not adequately suppress the rise in surface temperature when irradiated with a white infrared heat lamp. [Explanation of symbols]

[0083] 1 Case 2. Hard calcium silicate hydrate plate 3 White Infrared Heat Lamps 4. Leather-like sheet test piece 10 Surface temperature measurement box

Claims

1. A leather-like sheet comprising a fiber substrate and a colored resin layer laminated on the fiber substrate, The colored resin layer is made of polyurethane and a 3 to 20 g / m ２ and an infrared reflective black pigment, The infrared reflective black pigment has an average spectral reflectance of 8% or less in the wavelength range of 650 to 780 nm and an average spectral reflectance of 40% or more in the wavelength range of 780 to 2500 nm.

2. L ＊ a ＊ b ＊ In the color system, L ＊ Value ≦ 30, a ＊ 2. The leather-like sheet according to claim 1, having a surface with a value ≦1.

3. 3. The leather-like sheet according to claim 1, having a surface with an average solar reflectance of 30% or more in the wavelength range of 780 to 2500 nm.

4. The colored resin layer does not contain any pigment other than the infrared reflective black pigment, or does not contain any pigment other than the infrared reflective black pigment in an amount of 0.3 g / m ２ The leather-like sheet according to any one of claims 1 to 3, comprising the following ranges:

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