JP2008057062A - Leathery, sheet-like product and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a leathery, sheet-like product having fine images drawn by inkjet method or the like on the surface and practically sufficient physical properties. <P>SOLUTION: The leathery, sheet-like product has a porous layer on a fibrous base body and the surface of the porous layer has openings having ≥1μm diameter and images having ≥5 dot/mm resolution. Furthermore, it is preferable that the image is formed by pigment-based ink, the fibrous base body contains super fine fiber and the average diameter of the opening is 1-100μm. The method for producing the same is to open the porous layer on the fibrous base body and form the image on its surface by inkjet method. Furthermore, it is preferable that the porous layer is prepared by wet coagulation of a high molecular elastomer solution. Preferably, the method for opening the porous layer is to apply a solvent on the surface of the porous layer or to mechanically grind the surface of the porous layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a leather-like sheet having a fine image on its surface, and more particularly to a leather-like sheet having a clear image and excellent physical properties, and a method for producing the same.

  Conventionally, leather-like sheet-like materials have been used for a wide variety of purposes, and in particular, so-called silver-tone artificial leather having a polymer elastic layer on the surface has been devised in terms of appearance. As the appearance expression method, a method of applying a colored pattern on the surface of a sheet-like material by a conventionally known printing technique such as gravure printing or roller printing, a method of applying a colored pattern by transfer, or a colored pattern by printing or the like. The method of applying is adopted. These designs are expressed on the surface of the sheet-like material by designs such as gravure rolls, engraving rolls, screens for printing, etc. To change these colors and designs, engraving the design on the roll, and further adjusting the design. Need to repeat colors. Moreover, in these conventional methods, there is a limit to the range of expression and hue of the pattern, such as the restriction that only one color is colored in a single process, and it is a great deal to apply many delicate patterns to the surface of a sheet-like object. Had to spend money and time.

  On the other hand, in recent years, information patterns drawn on a computer by an ink jet printer can be printed in multiple colors in a short time in the printing field. This ink jet printing is characterized in that it can print various designs with various colors in a short time, unlike the conventional gravure printing, roller printing, transfer or textile printing described above. . However, unlike printing on paper, it is not easy to print on leather-like sheets, and various attempts have been made.

  For example, in Patent Document 1, an aqueous primer layer is formed on the surface of leather such as natural leather, and a microporous ink receiving layer containing alumina hydrate is further provided thereon, and the microporous ink receiving layer is provided. A leather product drawn on an ink-jet system is described. However, the porosity in this leather product is a nanometer order pore that depends on alumina hydrate, and the ink receptivity (dyeability) of the microporous ink receiving layer is not sufficient. Even when applied, a clear pattern is difficult to be formed, and the color tone of the pattern tends to be deep. Furthermore, in this method, the alumina hydrate constituting the microporous ink receiving layer is easily removed by friction, and is not practical enough to be applied to artificial leather processed into sports shoes and the like in terms of wear resistance. It was a thing.

In addition, attempts have been made to use pigment inks instead of dye-based inks as colorants. However, when a pattern is simply applied to the surface of leather using pigment ink, the pattern is applied. There was a problem that the adhesion between the layer and the adjacent layer was very weak due to the pigment particles that hindered adhesion. In particular, when a leather-like sheet is processed and molded into shoes, bags, etc., there is a problem that the bent part is peeled off or the image of the bent part is dropped. It was. That is, the present situation is that a leather-like sheet material that has a fine image on the surface and can withstand practical use has not been obtained.
JP 9-59700 A

  An object of the present invention is to provide a leather-like sheet having a fine image drawn by an inkjet method or the like on its surface and having practically sufficient physical properties.

  The leather-like sheet-like product of the present invention has a porous layer on a fibrous substrate, the surface of the porous layer has an opening having a diameter of 1 μm or more, and a resolution of 5 dots / mm or more on the surface. It has the image of this.

  Furthermore, the image is based on pigment-based ink, the pores of the porous layer communicate with the fibrous base, the fibrous base contains ultrafine fibers, and the polymer on the outermost surface. It is preferable that the elastic layer is formed, and that the average diameter of the apertures is 1 to 100 μm. Moreover, it is preferable that the surface is a silver tone or a nubuck tone.

Another method for producing a leather-like sheet according to the present invention is characterized in that a porous layer on a fibrous substrate is opened and an image is formed on the surface thereof by an ink jet method.
Furthermore, the porous layer is preferably obtained by wet coagulation of a polymer elastic body solution. Further, the method of opening the porous layer is preferably a method of applying a solvent to the surface of the porous layer or a method of mechanically grinding the surface of the porous layer.

  ADVANTAGE OF THE INVENTION According to this invention, the leather-like sheet-like material which has the fine design drawn by the inkjet system etc. on the surface, and has a practically sufficient physical property is provided.

The present invention is described in detail below.
The leather-like sheet material of the present invention has a porous layer on a fibrous substrate. As the fibrous base material used in the present invention, a fiber assembly or a composite fiber assembly in which this fiber assembly is impregnated with a polymer elastic body can be used, and those conventionally used for artificial leather are applicable. To do. The thickness is preferably 0.2 to 5 mm, more preferably 0.4 to 2.5 mm. Examples of the fiber assembly include non-woven fabrics and woven and knitted fabrics. Examples of the fibers constituting them include synthetic fibers such as polyester and polyamide, natural fibers such as cotton, hemp, and wool, or semi-synthetic fibers such as rayon. Moreover, these may be mixed 2 or more types.

  The fibrous base material preferably contains ultrafine fibers. Such a fibrous base material uses a non-woven fabric in which fibers having a single fiber fineness of 0.3 dtex or less, and further 0.1 to 0.0001 dtex are entangled as a fiber aggregate. By reducing the fineness of the single fiber, the surface of the obtained fibrous base becomes smooth, and it becomes possible to enhance the fine pattern drawn by the ink jet method or the like. Such a fiber having a single fiber fineness can be produced by a conventionally known method, and examples thereof include a sea-island spinning method, a mixed spinning method, and a split-type composite spinning method in synthetic fiber production. These fibers are made into a non-woven fabric by opening a relatively thick parent fiber before ultra-thinning into short fibers, then using a conventionally known card machine, entanglement with a needle machine, etc. It becomes a nonwoven fabric made of fibers. Methods for ultrafinening include extracting or decomposing components other than ultrafine fibers from the parent fibers obtained by the sea-island spinning method and the mixed spinning method, and the parent fibers obtained by the split-type composite spinning method as mechanical A method of chemically or chemically dividing can be employed. Typical examples of the polymer component to be extracted or decomposed and removed include polyethylene, polypropylene, polystyrene, and copolymers thereof, and examples of the polymer component that becomes an ultrafine fiber include polyesters such as polyethylene terephthalate and polyethylene naphthalate, and nylon. 6, polyamides such as nylon 6,6 and the like. In order to produce efficiently, it is preferable to make ultrafine nonwoven fabrics by spinning the split composite spinning and forming it directly into a web, then entangled with a needle machine or the like and mechanically splitting.

  Examples of the composite fiber assembly composed of a fiber assembly and a polymer elastic body used as a fibrous base material include the above-described fiber assembly impregnated with a polymer elastic body, solidified, and dried. Examples of the polymer elastic body include polyurethane, polyester elastomer, polyamide elastomer, polyolefin elastomer, and synthetic rubber such as polybutadiene and polyisoprene. Among these, polyurethane is preferably used from the viewpoints of wear resistance, elastic recovery, flexibility and the like. These polymer elastic bodies are used for impregnation as solutions or dispersions dissolved or dispersed in organic solvents. Preferably, these polymers are used for impregnation as an aqueous solution or water dispersion for the protection of the global environment and the working environment.

  In the present invention, it is essential to have a porous layer on the fibrous substrate and to have an opening having a diameter of 1 μm or more on the surface of the porous layer. The porosity in the porous layer of the present invention may be a communication hole or an independent hole, but it is preferable that the texture of the leather-like sheet is continuous. In particular, it is preferable that the pores of the porous layer communicate with the fibrous base material, resulting in a leather-like sheet having excellent breathability and moisture permeability.

The porous layer is preferably a layer made of a polymer elastic body. The thickness of the porous layer is preferably in the range of 0.05 mm to 1.5 mm. When the thickness is 0.05 mm or less, the unevenness of the fibrous layer cannot be completely concealed and it is difficult to obtain surface smoothness. Moreover, when the thickness of the layer is 1.5 mm or more, the texture as a leather-like sheet-like material becomes rubbery, which is not preferable. The density is preferably in the range of 0.2 to 0.7 g / cm ³ , more preferably 0.3 to 0.5 g / cm ³ , and the texture is improved. Examples of the polymer elastic body forming this layer include those used for the composite fiber assembly described above, and those having polyurethane as a main component are particularly preferable.

  As the polyurethane that can be used as a porous material, those used for artificial leather are suitable, and examples thereof include conventionally known thermoplastic polyurethanes obtained by polymerization reaction of organic diisocyanate, polymer diol and chain extender. it can. Organic diisocyanates include aliphatic, alicyclic or aromatic diisocyanates containing two isocyanate groups in the molecule, especially 4,4′-diphenylmethane diisocyanate, P-phenylene diisocyanate, toluylene diisocyanate, 1,5-naphthalene diisocyanate, Examples include xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, and the like. Examples of the polymer diol include at least one of polyester glycol obtained by condensation polymerization of glycol and aliphatic dicarboxylic acid, polylactone glycol obtained by ring-opening polymerization of lactone, aliphatic or aromatic polycarbonate glycol, or polyether glycol. Examples include polymer glycols having an average molecular weight of 500 to 4000 selected from seeds. Examples of chain extenders include diols having a molecular weight of 500 or less containing two hydrogen atoms capable of reacting with isocyanate, such as ethylene glycol, 1,4 butanediol, hexamethylene glycol, xylylene glycol, cyclohexanediol, and neopentyl glycol. Can be mentioned.

As a method for obtaining a porous layer using such a polymer elastic body, a conventionally known method can be employed. For example, a so-called wet coagulation method in which polyurethane is dissolved in an organic solvent that is a good solvent for polyurethane and is compatible with water, and this polyurethane solution is coated on a support with an arbitrary thickness and is immersed in a water bath to be porously solidified. Or a solution in which polyurethane is not compatible with water but dissolved or dispersed in an organic solvent that can dissolve or disperse polyurethane, or a dispersion is coated on the support with an arbitrary thickness to prevent water evaporation. A dry porous molding method that selectively evaporates the solvent, or a thermally expandable fine particle capsule dispersed in an aqueous solution of polyurethane or an aqueous dispersion, coated on a support with an arbitrary thickness, and dried while being thermally expanded. A method of swelling, or a prepolymer having an alcoholic hydrogen at the molecular end of a polyurethane A method in which an anate and water are mixed and immediately coated on a support in an arbitrary thickness, or a method in which an inert gas is dispersed in molten polyurethane to coat and foam on a support in an arbitrary thickness, or Examples thereof include a method in which a polyurethane solution or dispersion mixed with a chemical foaming agent is coated on a support with an arbitrary thickness. Among them, in order to obtain the porous material of the present invention, the wet coagulation method is particularly preferable because the shape of the pores can be easily controlled and the communication holes from the fibrous base material can be easily obtained.
A porous layer made of a polymer can be formed directly on the above-mentioned fibrous substrate by a coating method or the like.

  In the present invention, it is important that holes having a diameter of 1 μm or more are formed on the surface of the porous layer. In the present invention, a fine image is formed on the surface, but when the ink constituting the image enters into the holes present on the surface of the sheet-like material, unlike when the ink is simply applied to a flat surface, It is considered that the ink is prevented from dropping even when the surface is worn. Ink adhering to a flat surface is likely to be peeled off due to bending of the leather-like sheet, but the leather-like sheet of the present invention is difficult to cause such peeling and desorption of ink.

  The diameter of the aperture is essential to be 1 μm or more, preferably 3 to 150 μm, and most preferably 10 to 80 μm. When the pore diameter is less than 1 μm, the ink particles do not effectively enter the pores, so that the intended wear resistance or peel strength of the present invention cannot be obtained. In particular, when a pigment ink excellent in dyeing fastness and the like is used, the ink particle diameter is large, which is more remarkable. If the diameter of the opening is too large, the ink particles penetrate deeply into the hole, so that the fineness of the image is hindered and the resolution of the resulting leather-like sheet surface tends to be reduced. Therefore, the average diameter of the apertures is preferably in the range of 1 to 100 μm, and more preferably in the range of 5 to 70 μm.

The porous form present on the surface is also related to the surface state of the final leather-like sheet, and the leather-like sheet-like shape with silver has a smooth silver surface (polymer elastic layer). In the case of an article (artificial leather), there are few openings, for example, the number of openings on the silver surface is in the range of 100 to 5000 per 1 cm ² , and more preferably in the range of 500 to 3000. The average diameter of the apertures is preferably in the range of 5 to 70 μm, particularly preferably in the range of 10 to 30 μm, and an image with extremely high resolution can be formed. The total area of the apertures relative to the projected area of the surface is preferably 1% or less.
On the contrary, a nubuck-like surface, that is, a nubuck-like leather-like sheet-like material (artificial leather) having a surface as if the porous pores of the polymer elastic body are napped in natural leather. It is preferable that most of the surface is an aperture. Even when such a surface having a lot of nubuck-like irregularities is used, a fine pattern can be formed on the surface of the sheet-like material when ink released from one direction such as an ink jet is used. The influence does not significantly reduce the resolution of the image, and on the contrary, there is an effect that durability such as wear fastness is improved.

  The leather-like sheet material of the present invention has a porous layer having an aperture on the fibrous base as described above, and has an image having a resolution of 5 dots / mm or more on the surface thereof. It is preferable to have an image with a resolution of 10 dots / mm to 100 dots / mm. In order to print an image with such a fine resolution, it can be performed by using an inkjet printer of 360 dots / inch or 720 dots / inch. The image is preferably a pigment-based ink. When pigment-type ink is used, the particles are larger than dye-type ink, so that the light resistance and color transfer are excellent. In addition, since the image is formed on the surface having the opening portion, not the smooth surface of the leather-like sheet-like material as in the conventional case, the physical properties such as the adhesive strength are excellent. As the pigment, any of water-based, solvent-based, and UV-curing types can be used, and an appropriate one can be selected depending on the relationship with other surface treatments. However, in terms of wear resistance, UV-curing is possible. It is preferable to use a pigment-based ink.

  In the present invention, it is also preferable to have another polymer elastic body layer further outside the surface having the image. Such a polymer elastic body layer becomes a transparent or translucent protective layer, and can further improve the physical properties and texture of the leather-like sheet material, such as surface abrasion resistance. In the leather-like sheet-like material of the present invention, there are pores on the surface, there are irregularities, and the ink does not adhere much to the smooth surface, so a strong film is formed despite the presence of images. The In addition, it is possible to sufficiently obtain an interlayer adhesive force between the polymer elastic body layer serving as the protective film layer and the porous layer.

  Examples of the polymer elastic body used as the protective layer include polyurethane, polyester, polyester elastomer, polyamide, polyethylene, polypropylene, polyvinyl chloride, and polyvinylidene chloride.

  Such a polymer elastic body layer is formed by directly coating the surface of a sheet-like material having an image with an organic solvent solution, organic solvent dispersion, aqueous solution, or water dispersion of a polymer elastic body, followed by drying. As a coating method, knife coating, roll coating, spraying, gravure coating or the like can be employed. Alternatively, a polymer elastic body layer may be once formed on a release paper and adhered to a sheet-like material having an image. As an adhesive, conventionally known adhesives can be used, and among them, polyurethane-based materials can be used. An adhesive (polyisocyanate-based adhesive) is preferable, and either an organic solvent system or an aqueous system can be used.

  Another method for producing a leather-like sheet according to the present invention is a method in which a porous layer on a fibrous substrate is perforated and an image is formed on the surface thereof by an inkjet method. As the fibrous substrate and the porous layer, those described above can be used. The porous layer is preferably made of a polymer elastic body.

  As a method for obtaining such a porous layer, a conventionally known method can be adopted, but the porous layer is preferably obtained by wet coagulation of a polymer elastic body solution. In particular, the polyurethane is a good solvent for polyurethane and is dissolved in an organic solvent compatible with water, and this polyurethane solution is coated on a support with an arbitrary thickness, and is immersed in a water bath so as to be porous and solidified. Employing a solidification method is particularly preferable because the shape of the holes can be easily controlled and communication holes from the fibrous base material can be easily obtained. These porous layers can be formed directly on a fiber artificial leather substrate by coating or the like, or a porous film prepared on a peelable support is attached to a fibrous base material with an adhesive as a porous layer. May be combined.

Further, as a method for opening the porous layer on the fibrous substrate before forming an image, it is preferable to employ, for example, a method of applying a solvent to the surface of the porous layer or a method of mechanically grinding the surface of the porous layer. .
More specifically, the method of applying a solvent to open the porous layer is a good solvent, poor solvent, or good solvent as a component constituting the porous surface of the porous film formed on the fibrous base material. And a poor solvent mixed solvent or a mixed solvent of a good solvent and a non-solvent is applied with a gravure mesh roll to form an open hole. For example, when the component constituting the porous material is polyurethane, in order to make open pores appear on the surface of the porous polyurethane layer, the polyurethane good solvent, poor solvent, good solvent and It can be obtained by applying a mixed solvent of a poor solvent or a mixed solvent of a good solvent and a non-solvent with a gravure mesh roll.

  Here, the good solvent means a good solvent capable of dissolving polyurethane, for example, a component that is actually used. For example, dimethylformamide, tetrahydrofuran, dioxane and the like can be used for polyurethanes synthesized from aromatic organic diisocyanates. Examples include polar solvents. The poor solvent is a solvent that does not dissolve the components actually used but can swell. For example, in the case of polyurethane, ketones such as methyl ethyl ketone, alcohols such as isopropyl alcohol, and aromatic solvents such as toluene. Is mentioned. Further, the non-solvent is one that does not dissolve or swell the components actually used. For example, water is typically used for polyurethane. By selecting these solvents, it is possible to adjust the solubility with respect to the components constituting the porous material actually used, and it is possible to develop appropriate open pores. In this case, if a solvent having too strong solubility is used, an open hole once appears. However, due to its too strong solubility, the open hole is closed again in the process of evaporation drying of the solvent. On the other hand, when a solvent having too weak solubility is used, open pores do not appear.

When the method of applying this solvent is employed, an appropriately selected solvent is applied to the surface of the porous layer with a gravure mesh roll. In this case, the size of the mesh of the gravure mesh roll greatly affects the size of the diameter of the open hole to be formed. That is, if a roll with a fine mesh is used, an open hole with a relatively small diameter can be obtained, and if a roll with a coarse mesh is used, an open hole with a relatively large diameter can be obtained. Also, the coating pressure affects the size of the diameter of the open hole to be formed. That is, if the coating pressure is large, the obtained open hole has a large diameter, and if the coating pressure is small, the obtained open hole has a small diameter. As described above, by selecting an appropriate solvent, selecting a gravure mesh roll, and optimizing the coating pressure, an opening having a diameter of 1 μm or more can be expressed on the surface of the porous layer. The range is preferably 1 to 100 μm, more preferably 5 to 70 μm, and particularly preferably 10 to 30 μm. According to this method, a silver-like leather-like sheet (artificial leather) having a smooth silver surface (polymer elastic body layer) can be obtained, and the opening portion tends to be uniform and varies. Can be suppressed. In addition, it is easy to form an image with few apertures and extremely high resolution. The number of apertures on the silver surface is preferably in the range of 100 to 3000 per cm ² , and the total area of the apertures relative to the projected area of the surface is preferably 1% or less.

  Another method of mechanically grinding to open the porous layer is, more specifically, grinding the surface of the porous layer formed on the fibrous base material with a sandpaper or the like, a slicer, etc. In this method, the surface is cut off and the pores are exposed by removing the solid film portion on the porous surface.

  According to this method, it is possible to obtain a leather-like sheet-like material having a nubuck-like surface, that is, a surface as if the porous pores of the polymer elastic body are napped with natural leather. In this case, most of the surface of the leather-like sheet-like material is an aperture. Even if it has a surface with many nubuck-like irregularities, when an image is formed by the ink jet method, a fine pattern can be formed on the surface because the ink is released from one direction. The effect of this does not significantly reduce the resolution of the image, and conversely, durability such as wear fastness is improved.

  The production method of the present invention is a method for forming an image on the surface of the porous layer on the fibrous substrate thus opened by an inkjet method. The ink colorant is more preferably composed of a pigment in order to avoid light resistance and color shift. When pigment-type ink is used, the particles are larger than dye-type ink, so that the light resistance and color transfer are excellent. In addition, since the image is formed on the surface having the opening portion, not the smooth surface of the leather-like sheet-like material as in the prior art, the physical properties such as adhesive strength are excellent.

  The dispersion medium for the pigment ink may be either an organic solvent type, an aqueous type, or a UV curing type, and an appropriate one can be selected depending on the relationship with other surface treatments. In this respect, it is most preferable to use a UV curable pigment ink. The design can be arbitrarily selected, and characters, photographs, design drawings, etc. can be printed by a commonly used inkjet printer. The ink jet printer prints a pattern on the surface of the porous layer having a hole formed on the basis of data sent from an image development unit of a computer. The resolution of the printed image is preferably 5 dots / mm or more, and more preferably an image having a resolution of 10 dots / mm to 100 dots / mm. In order to print an image with such a fine resolution, it can be performed by using an inkjet printer of 360 dots / inch or 720 dots / inch. Although the printed leather-like sheet can be a product as it is, it is preferably heat-treated at 80 ° C. to 150 ° C. for about 20 to 60 seconds after forming an image with an ink jet printer.

  In the present invention, it is also preferable to provide another polymer elastic body on the outer side of the surface having the image. The thus formed and formed elastic polymer layer becomes a transparent or translucent protective layer, and can further improve the physical properties and texture of the leather-like sheet material, such as surface abrasion resistance. In the leather-like sheet-like material obtained by the production method of the present invention, there are openings on the surface, there are irregularities, and there is not much ink adhering to the smooth surface, so there is an image. A strong film is formed. In addition, a sufficient interlaminar adhesive force between the elastic polymer layer serving as the protective film layer and the porous layer can be obtained.

  The leather-like sheet-like material of the present invention thus obtained has fine patterns, and the leather-like sheet-like materials having these patterns are used for various applications such as wear resistance and artificial leather. It has physical properties such as peel strength that can withstand. The image given to the leather-like sheet-like material of the present invention can be freely and easily expressed as a design on the surface of the leather-like sheet-like material using a computer or the like connected to an inkjet printer. As a result, you can create your own design that emphasizes individuality in sports shoes, leather shoes, various competition balls, bindings, clothing, and furniture / vehicles that have traditionally used leather-like sheets. It will be useful.

  Hereinafter, the present invention will be described in detail by way of specific examples. In the examples, “parts” and “%” are based on weight, and the characteristic measurement values are obtained by the following method. In the following examples, light fastness, color transfer resistance, abrasion resistance and peel strength were measured by the following methods.

(Light fastness)
Observe the discoloration after carbon arc light irradiation for 50 hours in accordance with JIS-L0824. Grade 5 is the one with no change, and grade 1 is the one where the original design cannot be read. The original design was left but the fading color was judged as 3rd grade.

(Color resistance)
A surface of a leather-like sheet having a pattern printed by the ink jet method obtained in each example and comparative example on the surface, and a surface of a general white artificial leather having a surface formed of polyurethane, A6 size The color transition to the surface of the white artificial leather after observing the color transition to the surface of the white artificial leather after being allowed to stand in an atmosphere of 70 ° C. for 3 days with a uniform load of 2 kg was applied. The grade 5 was determined to be grade 1, and the white artificial leather colored almost on the entire surface was classified as grade 1 and those with an area of 30% to 50% colored as grade 3.

(Abrasion resistance)
In accordance with ASTM D-3886 method, HANDY ROLL P320J (manufactured by NORTON) was used as a sandpaper, and the number of times the exposed fiber layer of the worn part reached 10 mm in diameter.

(Stripping strength)
In accordance with JIS K6301 method, the film was peeled 100 mm at a pulling speed of 50 mm / min, and the average value of 5 minimum values for each 20 mm was represented by N / cm, and the peel strength was designated.

[Example 1]
<Creation of fiber assembly-1>
Nylon-6 (intrinsic viscosity 1.1 in m-cresol) dried at 120 ° C. was fed to an extruder and melted. Separately dried polyethylene terephthalate (at an intrinsic viscosity of 0.64 in o-chlorophenol) at 160 ° C. was melted with an extruder separate from the foregoing. Subsequently, the nylon-6 mixture melt flow was introduced into a spin block maintained at 275 ° C. at a conduit polymer temperature of 250 ° C., the polyethylene terephthalate melt flow at 300 ° C., and a rectangular shape having hollow forming discharge holes in a lattice arrangement. The two polymer melt flows are combined using a spinneret, combined and discharged at a rate of 2 g / min. / Hole, and an air pressure of 0.35 MPa (spinning speed converted from the discharge rate and composite fiber fineness is about 4860 m / min). Towed at high speed. The pulled composite fiber is subjected to a high voltage application treatment at −30 kV, collided with a dispersion plate together with an air flow, opened, and a net conveyor as a web composed of a split split composite fiber having a 16-split multi-layer laminated cross section. Collected 1m wide above. Subsequently, the obtained web was passed through a pair of upper and lower embossed calender rolls heated to 100 ° C. and thermally bonded. The resulting web is entangled with a needle punch, then immersed in water, lightly squeezed with a mangle, and then subjected to a separation-splitting treatment with a sheet-like material striking-type squeezing machine to give an ultrafine fiber nonwoven fabric with a basis weight of 210 g / m ² Got. Next, this nonwoven fabric was contracted in warm water at 70 ° C. to obtain an area of 60% of the area before contraction.
The obtained fiber assembly-1 had a basis weight of 350 g / m ² , a thickness of 1.0 mm, and a fineness of 0.15 dtex.

<Preparation of a fibrous substrate (composite structure) -1 having a polymer porous layer on its surface>
After impregnating the above-mentioned fiber assembly-1 with a 10% by weight polyurethane (Dainippon Ink Chemical Co., Ltd .; Crisbon TF50P) -dimethylformamide (hereinafter referred to as DMF) solution, the surface of the fiber assembly The excess solution is scraped off and immersed in water containing 5% DMF for 20 minutes to coagulate the polyurethane, and the DMF is thoroughly washed away with water and dried at 120 ° C. for 4 minutes to form a fibrous substrate (composite structure). Product).
The surface of the obtained fibrous base body (composite structure) having no porous layer was a mixture of fibers and polyurethane, having a basis weight of 455 g / m ² and a thickness of 1.0 mm.

20 parts by weight of polyurethane (manufactured by Dainippon Ink & Chemicals, Inc .; Chris Bon TF50P) -DMF solution (100 parts of Toray Dow Corning SH28PA as an additive on the surface of the fibrous base material having no porous layer Coating with a weight per unit area of 800 g / m ² , and then immersed in water containing 5% DMF for 20 minutes to coagulate the polyurethane and thoroughly wash away the DMF with water. Drying at 5 ° C. for 5 minutes gave a fibrous substrate-1 having a polymer porous layer having a polyurethane porous layer (wet porous layer) having a density of 0.39. The peel strength of the obtained substrate was 31.2 N / cm, and it was strong enough to be used in various uses of artificial leather including sports shoes.

<Creation of sheet-like material-1 having an aperture on the surface>
A mixture of methyl ethyl ketone 40% and dimethylformamide 60% was applied to the surface of the fibrous substrate-1 having the polyurethane porous layer described above with a gravure coating machine (using a 110 mesh roll) at a pressure of 4 kg / cm ^2. Dry and open the holes. When the surface of the obtained sheet-like material-1 was observed with a scanning electron microscope, 2050 open holes with an average of 30 μm were formed per square centimeter. The maximum diameter of the release hole was 55 μm.

<Creation of artificial leather (leather-like sheet) -1>
A landscape image with a resolution of 720 DPI (dots / inch) is printed on the surface of the sheet-like material-1 using an organic solvent-based pigment ink (ECO-SOLMAX) with an inkjet printer (SJ-545EX, manufactured by Roland). Then, heat treatment was performed at 120 ° C. for 1 minute to obtain artificial leather (leather-like sheet-like material) -1. The inks used were cyan ESL3-CY, magenta ESL3-MG, yellow ESL3-YE, light cyan ESL3-LC, light magenta ESL3-LM, and black ESL3-BK. The surface of the obtained artificial leather-1 was printed with a fine and clear image. In addition, when light fastness was measured, there was no change and it was favorable by the 5th grade determination. Moreover, there was no color transfer resistance and it was judged as grade 5 and was good. The peel strength was 30.7 N / cm, and the peeled portion was the interface between the nonwoven fabric layer and the polyurethane porous layer at the time of peel strength measurement before inkjet printing. The abrasion resistance was 370 times. The physical properties of Table 1 are shown.

[Example 2]
<Creation of sheet-like material-2 having an aperture on the surface>
Using the buffing machine on which the surface of the unopened polyurethane porous layer of the fibrous substrate (composite structure) -1 obtained in Example 1 was fitted with a 200-mesh sandpaper, The surface was ground by adjusting the number of rotations of the sandpaper loaded roll and the gap between the rolls so that the average was 50 μm. There were innumerable apertures obtained, and the maximum aperture diameter was 110 μm, with an average of 55 μm.

<Creation of artificial leather (leather-like sheet) -2>
A landscape image with a resolution of 720 DPI (dots / inch) is printed on the surface of the sheet-like material-2 using an organic solvent-based pigment ink (ECO-SOLMAX) with an inkjet printer (Roland, SJ-545EX). Then, heat treatment was performed at 120 ° C. for 1 minute to obtain artificial leather (leather-like sheet-like material) -2. The inks used were cyan ESL3-CY, magenta ESL3-MG, yellow ESL3-YE, light cyan ESL3-LC, light magenta ESL3-LM, and black ESL3-BK. The surface of the obtained artificial leather-2 was printed with a fine and clear image. In addition, when light fastness was measured, there was no change and it was favorable by the 5th grade determination. Moreover, there was no color transfer resistance and it was judged as grade 5 and was good. The peel strength was 31.2 N / cm, and the peeled portion was the interface between the nonwoven fabric layer and the polyurethane porous layer at the time of peel strength measurement before ink jet printing. Moreover, the wear resistance was 320 times. Table 1 also shows the physical properties.

[Examples 3 and 4]
<Creation of artificial leather (leather-like sheet) -3, 4>
On a release paper (R53 manufactured by Lintec Corporation), a thickening agent was mixed with 100 parts of a 33% aqueous dispersion of polyurethane resin, and the mixture prepared by stirring and adjusting the viscosity to 8000 CPS was coated at a weight of 90 g / m ² . The polymer elastic body film was formed by drying at a temperature of 70 ° C. for 2 minutes and at 110 ° C. for 2 minutes. Furthermore, the surface was coated with a preparation solution prepared by mixing a thickener with 100 parts of a water-dispersed polyurethane adhesive and adjusting the viscosity to 5000 CPS at a weight of 80 g / m ² . Next, after drying at 90 ° C. for 2 minutes, the release paper-like polymer elastic body and the artificial leather (leather-like sheet-like material) -1 obtained in Example 1 are superposed and heated at a temperature of 110 ° C. It was passed through a roll with a gap of 0.6 mm on the cylinder surface and pressed. Then, after leaving for 2 days in an atmosphere at a temperature of 60 ° C., the release paper was peeled off to obtain artificial leather (leather-like sheet-like material) -3.
Further, instead of using the artificial leather-1 obtained in Example 1, artificial leather (leather-like sheet-like material) − except that the artificial leather-2 obtained in Example 1 was used— 4 was obtained.
The obtained artificial leathers -3 and 4 both had good light fastness and color transfer resistance. The peel strength was also high, and the peeled portion was in the nonwoven fabric layer at the time of peel strength measurement before ink jet printing. Also, the wear resistance was good. Table 1 also shows the physical properties.

[Example 5]
<Creation of artificial leather (leather-like sheet) -5>
Instead of using an organic solvent pigment ink on the surface of the sheet-like material-2 having an aperture on the surface obtained in Example 2, an aqueous pigment ink (PM-4000PX, manufactured by EPSON) was used with an aqueous pigment ink ( Artificial leather (leather-like sheet) in the same manner as in Example 2 except that a landscape image with a resolution of 720 DPI (dots / inch) was printed using PX-P ink and then heat-treated at 120 ° C. for 1 minute. -5) was obtained. The inks used were cyan ICC23, magenta ICM23, yellow ICY23, light cyan ICLC23, light magenta ICLM23, gray ICGY23, photo black ICBK23, and matte black ICMB23. A fine and clear image was printed on the surface of the obtained artificial leather-5. In addition, when light fastness was measured, there was no change and it was favorable by the 5th grade determination. Moreover, there was no color transfer resistance and it was judged as grade 5 and was good. The peel strength was 30.8 N / cm, and the peeled portion was the interface between the nonwoven fabric layer and the polyurethane porous layer when the peel strength was measured before ink jet printing. Further, the wear resistance was 330 times. Table 1 also shows the physical properties.

[Example 6]
<Creation of artificial leather (leather-like sheet) -6>
Instead of using an organic solvent-based pigment ink on the surface of the sheet-like material-2 having an aperture on the surface obtained in Example 2, a UV curable pigment was used with an inkjet printer (RP-720UVZ, manufactured by Raster Printer). Artificial leather (leather) in the same manner as in Example 2 except that a landscape image having a resolution of 720 DPI (dots / inch) was printed using inks of the types (cyan, magenta, yellow, light cyan, light magenta, and black). Like sheet-like material) -6. A fine and clear image was printed on the surface of the obtained artificial leather-6. In addition, when light fastness was measured, there was no change and it was favorable by the 5th grade determination. Moreover, there was no color transfer resistance and it was judged as grade 5 and was good. The peel strength was 29.7 N / cm, and the peeled portion was the interface between the nonwoven fabric layer and the polyurethane porous layer when the peel strength was measured before inkjet printing. The abrasion resistance was 590 times. Table 1 also shows the physical properties.

[Comparative Example 1]
A fibrous substrate (composite structure) having a porous layer that is not opened on the surface, obtained in the middle of Example 1, instead of using a sheet-like material having an aperture on the surface of Example 1 for printing. Except for using -1, using an organic solvent pigment ink (ECO-SOLMAX) in an inkjet printer (Roland, SJ-545EX) in the same manner as in Example 1, the resolution of 720 DPI (dots / inch) A landscape image was printed to obtain artificial leather. The surface of the obtained artificial leather had a fine and clear image printed thereon. In addition, when light fastness was measured, there was no change and it was favorable by the 5th grade determination. Moreover, there was no color transfer resistance and it was judged as grade 5 and was good. However, the peel strength was as low as 5.2 N / cm, and the peeled portion was a pigment layer for ink jet printing, and was not a material that could withstand the use of each application as an artificial leather. The abrasion resistance was 10 times, which was caused by peeling of the pigment layer. Table 1 also shows the physical properties.

[Example 7]
<Creation of fiber assembly-2>
Nylon 6 and low density polyethylene were mixed at 50/50, melted and mixed with an extruder, mixed and spun at 290 ° C., drawn, treated with an oil agent and cut to obtain 5.5 dtex, 51 mm fiber. This was passed through the steps of a card, a cross wrapper, a needle locker, and a calendar to obtain a fiber assembly-2 having a weight of 400 g / m ² , a thickness of 1.6 mm, and an apparent density of 0.25 g / cm ³ .

<Preparation of a fibrous substrate (composite structure) -2 having a polymer porous layer on its surface>
The above fiber assembly-2 was dipped in 10% by weight of polyurethane (Dainippon Ink Chemical Co., Ltd .; Crisbon TF50P) -DMF solution, and then the excess solution on the surface of the fiber assembly was scraped off to obtain the substrate thickness. 20% by weight of polyurethane (manufactured by Dainippon Ink & Chemicals, Inc .; Chris Bon TF50P) -DMF solution (as additive, SH28PA manufactured by Toray Dow Corning) Was coated with a basis weight of 800 g / m ² , and then immersed in water containing 5% DMF to solidify the polyurethane, and the DMF was thoroughly washed away with water. Thereafter, the sheet was dried at 120 ° C. to obtain a sheet on which a polyurethane porous layer was formed. The obtained sheet was repeatedly compressed and relaxed in hot toluene at 90 ° C., the polyethylene component in the fiber was extracted and removed, and a polyurethane porous layer having a fine fiber of 0.003 dtex as a fibrous base material was formed. A fibrous substrate (composite structure) -2 having a polymer porous layer on the surface was prepared. The peel strength of the obtained fibrous base material-2 was 35.7 N / cm, and it was strong enough to withstand use in various uses of artificial leather including sports shoes.

<Creation of sheet-like material-3 having an aperture on the surface>
Using a 110 mesh gravure roll on the surface of the fibrous base material-2 having the polyurethane porous layer, 4 kg of a mixed solution of dimethylformamide: methyl ethyl ketone = 7: 3 is used with a gravure coating machine (using a 150 mesh roll). It was applied and dried at a pressure of / cm ² to open the holes. When the surface of the obtained sheet-like material-3 was observed with a scanning electron microscope, 1800 open holes / cm ² having an average value of 15 μm were formed. The maximum diameter of this open hole was 40 μm.

<Creation of artificial leather (leather-like sheet) -7>
Instead of using the sheet-like material-1 having an aperture on the surface of Example 1 for printing, an inkjet printer (SJ, manufactured by Roland Corporation) was used in the same manner as in Example 1 except that the sheet-like material-3 was used. -545EX) was used to print a landscape image with a resolution of 720 DPI (dots / inch) using an organic solvent pigment ink (ECO-SOLMAX) to obtain artificial leather (skin-like sheet-like material) -7. A fine and clear image was printed on the surface of the obtained artificial leather-7. In addition, when light fastness was measured, there was no change and it was favorable by the 5th grade determination. Moreover, there was no color transfer resistance and it was judged as grade 5 and was good. The peel strength was 36.2 N / cm, and the peel location was the interface between the nonwoven fabric layer and the polyurethane porous layer at the time of peel strength measurement before ink jet printing. Further, the wear resistance was 440 times. Table 2 shows the physical properties.

[Example 8]
<Creation of artificial leather (leather-like sheet) -8>
Instead of using an organic solvent pigment ink on the surface of the sheet-like material-3 having an aperture on the surface obtained in Example 7, an aqueous pigment ink (PM-4000PX, manufactured by EPSON) was used. Artificial leather (leather-like sheet) in the same manner as in Example 7 except that a landscape image with a resolution of 720 DPI (dots / inch) was printed using PX-P ink and then heat-treated at 120 ° C. for 1 minute. -8) was obtained. The inks used were cyan ICC23, magenta ICM23, yellow ICY23, light cyan ICLC23, light magenta ICLM23, gray ICGY23, photo black ICBK23, and matte black ICMB23. A fine and clear image was printed on the surface of the obtained artificial leather-8. In addition, when light fastness was measured, there was no change and it was favorable by the 5th grade determination. Moreover, there was no color transfer resistance and it was judged as grade 5 and was good. The peel strength was 30.5 N / cm, and the peeled portion was the interface between the nonwoven fabric layer and the polyurethane porous layer when the peel strength was measured before ink jet printing. Further, the wear resistance was 390 times. Table 2 also shows the physical properties.

[Example 9]
<Making Artificial Leather (Leather-like Sheet) -9>
Instead of using an organic solvent pigment ink on the surface of the sheet-like product-3 having an aperture on the surface obtained in Example 7, a UV curable pigment was used with an ink jet printer (Raster Printer, RP-720UVZ). Artificial leather (leather) in the same manner as in Example 7 except that a landscape image with a resolution of 720 DPI (dots / inch) was printed using the types of inks (cyan, magenta, yellow, light cyan, light magenta, and black). Like sheet) -9. A fine and clear image was printed on the surface of the obtained artificial leather-9. In addition, when light fastness was measured, there was no change and it was favorable by the 5th grade determination. Moreover, there was no color transfer resistance and it was judged as grade 5 and was good. The peel strength was 34.7 N / cm, and the peeled portion was the interface between the nonwoven fabric layer and the polyurethane porous layer when the peel strength was measured before ink jet printing. Further, the wear resistance was 1360 times. Table 2 also shows the physical properties.

[Example 10]
<Making Artificial Leather (Leather-like Sheet) -10>
Instead of using an organic solvent pigment ink on the surface of the sheet-like product-3 having an aperture on the surface obtained in Example 7, dye ink (IC5CL06, and an ink printer, manufactured by EPSON, PM3700C) Artificial leather (leather-like sheet-like material) -10 was obtained in the same manner as in Example 7 except that a landscape image with a resolution of 720 DPI (dots / inch) was printed using IC1BK05). The surface of the obtained artificial leather-10 was printed with a fine and clear image. However, when the light fastness was measured, the color was partially faded and was far from the original color. It was a judgment. Further, the color transfer resistance was also judged as a third grade, and the color was transferred to the surface of the white artificial leather. The peel strength was 32.9 N / cm, almost the same as that before printing with an ink jet printer, and the wear resistance was 410 times. Table 2 also shows the physical properties.

[Comparative Example 2]
A fibrous base material having a porous layer which is not opened on the surface, obtained in the middle of Example 7, instead of using the sheet-like material-3 having an aperture on the surface obtained in Example 7 for printing. (Composite Structure) -2 Using a dye ink (IC5CL06 and IC1BK05) with an inkjet printer (manufactured by EPSON, PM3700C) in the same manner as in Example 10 except that the composite structure-2 is used, a resolution of 720 DPI (dot / inch) An artificial leather was obtained. The surface of the resulting artificial leather was printed with a fine and clear image. However, when the light fastness was measured, the color was partially discolored and it was far from the original color. Met. Further, the color transfer resistance was also judged as a third grade, and the color was transferred to the surface of the white artificial leather. Further, the peel strength was as low as 11.5 N / cm, and the peeled portion was a pigment layer for ink jet printing, and it was not capable of withstanding the use of each application as artificial leather. Further, the wear resistance was 32 times, which was caused by peeling of the pigment layer. Table 2 also shows the physical properties.

Claims (12)

  A leather having a porous layer on a fibrous substrate, the surface of the porous layer having an opening having a diameter of 1 μm or more, and an image having a resolution of 5 dots / mm or more on the surface. Like sheet.   The leather-like sheet-like material according to claim 1, wherein the image is obtained from a pigment-based ink.   The leather-like sheet material according to claim 1 or 2, wherein the pores of the porous layer communicate with the fibrous base material.   The leather-like sheet material according to any one of claims 1 to 3, wherein the fibrous base material contains ultrafine fibers.   The leather-like sheet-like material according to any one of claims 1 to 4, wherein a polymer elastic layer is formed on the outermost surface.   The leather-like sheet material according to any one of claims 1 to 5, wherein an average diameter of the apertures is 1 to 100 µm.   The leather-like sheet-like material according to any one of claims 1 to 6, wherein the surface has a silver tone.   The leather-like sheet material according to any one of claims 1 to 6, wherein the surface is nubuck-like.   A method for producing a leather-like sheet-like material, wherein a porous layer on a fibrous substrate is opened and an image is formed on the surface thereof by an ink jet method.   The method for producing a leather-like sheet material according to claim 9, wherein the porous layer is obtained by wet coagulation of a polymer elastic body solution.   The method for producing a leather-like sheet-like material according to claim 9 or 10, wherein the method of opening the porous layer is a method of applying a solvent to the surface of the porous layer.   The method for producing a leather-like sheet according to claim 9 or 10, wherein the method of opening the porous layer is a method of mechanically grinding the surface of the porous layer.