JP2023065062A - Artificial leather and manufacturing method thereof - Google Patents

Abstract

To provide a suede-like artificial leather, which is excellent in pattern retention and provided with arbitrary pattern, and a manufacturing method thereof.SOLUTION: A suede-like artificial leather has raised hair appearance including at least an outer surface fiber layer constituting an outer surface and elastomer. The outer surface has a colored portion of at least one color or more. The outer surface has a pattern consisting of the colored portion. The outer surface fiber layer is continuously colored to depth of 0.30 mm or more in a thickness direction from the outer surface at the colored portion. The outer surface fiber layer is formed of ultra fine fibers having average diameter of 2.0 μm or more and 4.5 μm or less. The suede-like artificial leather and a manufacturing method of the suede-like artificial leather are provided.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to artificial leather and its manufacturing method.

Artificial leather, which is mainly composed of a fiber sheet formed by entangling a fiber web, has excellent features such as easy care, functionality, and homogeneity, which are difficult to achieve with natural leather. It is suitably used for clothing, shoes, bags, and also for interior materials, automobiles, aircraft, railroad vehicles, and other sheet covering materials and interior materials, and clothing materials such as ribbons and emblem base materials. there is

Among them, it is demanded to impart arbitrary color tone and pattern to surface materials and interior materials such as automobile seats as a means of imparting unique design properties. For example, dyeing with a jet dyeing machine or the like is generally used as a means for imparting an arbitrary color tone to artificial leather. By dyeing brushed artificial leather with a brushed surface with a liquid jet dyeing machine, it is possible to dye it in any color according to the dyeing recipe. Furthermore, the kneading effect of liquid jet dyeing creates a luxurious, flexible texture and suede-like texture. You can get a feeling of brushed. On the other hand, in dyeing with a jet dyeing machine, the substrate is dyed in a state in which it is uniformly impregnated with a dyeing solution, so that the entire artificial leather obtained is dyed in a single color. The outer surface is the surface that is expected to come into contact with or be visually recognized when the material or the like is used as a product (for example, in the case of automobile seats, the surface that comes into contact with the human body or clothing).

Inkjet printing is being considered as a means of adding arbitrary patterns to artificial leather. Patent Literature 1 below describes ink-jet printing on fibrous structures containing microfibers of 1 denier or less. By using inkjet printing, any design can be printed on the outer surface of the fiber structure. In addition, it is described that a large amount of dye is required for sufficient dyeing of ultrafine fibers, but the amount of dye used can be reduced because inkjet printing is limited to coloring the outer surface of the fiber structure.
In Patent Document 2 below, after uniformly coloring the entire sheet-like material to be an artificial leather with a pigment in a single color, the outer surface of the sheet-like material is ink-jet printed. This avoids exposure of uncolored fibers at the edges, which is one of the problems of inkjet printing. Further, it is described that when the outer surface printed by ink-jet printing is scraped by abrasion, the fiber layer colored with the pigment is exposed on the abraded surface after abrasion, so that the quality is less likely to be impaired.

Japanese Patent Publication No. 7-88635 JP 2018-127736 A

An artificial leather to which an arbitrary pattern is applied by inkjet printing is required to maintain the pattern similar to that of the outer surface before abrasion even if the outer surface is scraped by friction. In this specification, the ability of the outer surface after abrasion to maintain the same pattern as that of the outer surface before abrasion is also referred to as pattern retention.
Patent Literatures 1 and 2 do not consider the maintenance of the design on the outer surface after abrasion (design retention). Further, in Patent Document 2, a binder is used for fixing the pigment, and the obtained artificial leather has a hard texture, so there is room for improvement.

In view of the level of such prior art, the problem to be solved by the present invention is to provide an artificial leather with an arbitrary pattern, which is excellent in pattern retention, and a method for producing the same.

In order to solve the above problems, the present inventors have conducted extensive research and repeated experiments. As a result, in artificial leather to which an arbitrary pattern is applied by inkjet printing, a colored portion is formed to a predetermined depth or more in the thickness direction from the outer surface. By making the fibers exist continuously and making the average diameter of the fibers constituting the fiber layer in the colored portion within a predetermined range, the exposure of uncolored fibers or uneven coloring on the worn surface is suppressed, and the outer surface before abrasion and the The present inventors have unexpectedly found that the same pattern is maintained, that is, the pattern retainability is improved, and have completed the present invention.

That is, the present invention is as follows.
[1] A suede-like artificial leather having a brushed appearance that includes at least an outer surface fiber layer that constitutes the outer surface and a polymeric elastic body,
The outer surface has at least one colored portion,
The outer surface has a pattern composed of the colored portion,
In the colored portion, the outer surface fiber layer is colored continuously from the outer surface to a depth of 0.30 mm or more in the thickness direction, and
A suede-like artificial leather, wherein the outer surface fiber layer is composed of ultrafine fibers having an average diameter of 2.0 μm or more and 4.5 μm or less.
[2] The suede-like artificial leather according to [1], wherein the ultrafine fibers are polyester fibers.
[3] The suede-like artificial leather according to [1] or [2], which has a stiffness value of 28 cm or less.
[4] The suede-like artificial leather described in any one of [1] to [3] above, wherein the suede-like artificial leather is a sheet-like material composed of two or more layers including at least a woven or knitted scrim and the outer surface fiber layer. suede-like artificial leather.
[5] the following steps:
(1) A step of forming a fiber web from ultrafine fibers having an average diameter of 2.0 μm or more and 4.5 μm or less;
(2) entangling the resulting fibrous web to obtain a fibrous sheet;
(3) optionally raising the outer surface of the obtained fiber sheet;
(4) filling the resulting fiber sheet with an elastic polymer to obtain a sheet;
(5) Raising the outer surface of the sheet material obtained in step (4) when step (3) is not performed;
(6) A step of continuously inkjet-printing the obtained sheet-like material to a depth of 0.30 mm or more in the thickness direction from the outer surface; and (7) reducing and washing the inkjet-printed sheet-like material. , obtaining a patterned artificial leather;
The method for producing a suede-like artificial leather according to any one of [1] to [4] above.

The artificial leather according to the present invention is an artificial leather with an arbitrary pattern that is excellent in pattern retention, and is used for interiors, automobiles, aircraft, railway vehicles, etc. It can be suitably used for products and the like.

FIG. 4 is a schematic diagram of color depth measurement; 1 is a schematic diagram of fiber average diameter measurement; FIG. This is a design A for inkjet printing.

Embodiments of the present invention will be described in detail below, but the present invention is not limited to the embodiments. Also, the various values in this disclosure, unless otherwise specified, are the values obtained by the methods described in the Examples section of this disclosure or equivalent methods understood by those skilled in the art.

<artificial leather>
One embodiment of the present invention is a suede-like artificial leather having a brushed appearance that includes at least an outer surface fiber layer that constitutes the outer surface and a polymeric elastic body,
The outer surface has at least one colored portion,
The outer surface has a pattern composed of the colored portion,
In the colored portion, the outer surface fiber layer is colored continuously from the outer surface to a depth of 0.30 mm or more in the thickness direction, and
The suede-like artificial leather, wherein the outer surface fiber layer is composed of ultrafine fibers having an average diameter of 2.0 μm or more and 4.5 μm or less.

In this specification, "artificial leather" refers to "a special non-woven fabric (mainly a fiber layer having a random three-dimensional structure, made of polyurethane (PU) resin or similar flexible impregnated with a polymeric elastic body having In addition, according to the definition of JIS-6601, artificial leather is classified according to its appearance into "smooth" leather with grain-like appearance and "nap" leather with suede, velor, etc. appearance. The artificial leather of the embodiment relates to what is classified as "nap" (that is, suede-like artificial leather having a brushed appearance). The suede-like appearance can be formed by buffing (raising) the outer surface (also referred to as the front surface) of the artificial leather with sandpaper or the like. In this specification, the outer surface of the artificial leather is the surface that is exposed to the outside when the artificial leather is used (for example, the surface that comes into contact with the human body or clothes in the case of use as a chair). In one aspect, in the case of suede-like artificial leather, the outer surface of the artificial leather is raised or raised by buffing or the like. Among these, the present invention relates to suede-like artificial leather.

Synthetic fibers can be used as fibers constituting the artificial leather of the present embodiment. For example, polyester fibers such as polyethylene terephthalate, polybutylene terephthalate, and polytrimethylene terephthalate, as well as synthetic fibers such as polyamide fibers such as nylon 6, nylon 66, and nylon 12 are suitable as fibers constituting artificial leather. Among them, polyester fiber does not turn yellow even when exposed to direct sunlight for a long time, and has excellent color fastness when considering applications that require durability such as car seats. point is preferable. Further, from the viewpoint of reducing environmental load, chemically recycled or material recycled polyethylene terephthalate, polyethylene terephthalate using a plant-derived raw material, or the like is more preferable.

The artificial leather of this embodiment has a colored portion on the outer surface. The colored portion is a portion that can be visually determined to be colored by being composed of colored fibers or by containing a coloring agent in the elastic polymer that is the binder of the fibers. Among them, the coloring of the fiber is caused by the coloring agent fixed on the surface of the fiber or diffused and permeated inside the fiber. Examples of the coloring agent include various dyes and pigments such as direct dyes, sulfur dyes, reactive dyes, acid dyes, metal-containing (metal complex salt) dyes, disperse dyes, and cationic dyes, or mixtures containing them (eg ink). and is not limited to that type. Equipment used for coloring includes various dyeing machines such as jet dyeing machines, wince dyeing machines, cheese dyeing machines, jigger dyeing machines, and various printing machines such as inkjet printers and roller printing machines. In this specification, "coloring" refers to coloring in general regardless of the type of coloring agent, and "dyeing" refers to coloring using a coloring agent containing a dye regardless of the equipment used.

The artificial leather of this embodiment has at least one colored portion on its outer surface, and the colored portion forms a pattern. More specifically, the design is defined by the color difference between one colored portion and a colored portion of a different color or a non-colored portion (having the color of the undyed fibers). In addition, "color difference" indicates that each color is different from each other. Specifically, when there are two kinds of colors (color A and color B), "color difference" means L ^* , a ^* , and b ^* (described later) of any two points (point A and point B) in each color. means that at least one of the following formulas (1), (2), and (3) is satisfied.
|L ^* _A -L ^* _B |>5 Expression (1)
|a ^* _A −a ^* _B |>5 Expression (2)
|b ^* _A −b ^* _B |>5 Expression (3)
When there are three or more colors, the "color difference" means at least one of the above formulas (1), (2), and (3) as color A and color B for all combinations of two colors. It refers to satisfying any one expression.
In addition, for example, when the color boundary is complicated or when the color boundary is not clear (gradation, etc.), L ^* , a ^* , and b ^* of each color can be measured with good reproducibility using a colorimeter (described later). When it is difficult to do so, set an arbitrary point A on the colored part on the outer surface of the artificial leather, and on a circle with a diameter of 4 cm centered on point A (and on the colored part), and each Select any three points (point B1, point B2, and point B3) whose line segments connecting the points form an equilateral triangle, and three combinations of the point A and the three points B are all expressed by the above formula (1) , Formula (2), and Formula (3).

L ^* , a ^* , and b ^* at a point on the colored portion of the outer surface of the artificial leather of the present embodiment were measured using a spectrophotometer ("SPECTROPHOTOMETER CM-5" manufactured by KONICA MINOLTA) under the following conditions: can be obtained by colorimetry.
Measurement type: reflection measurement (Ref)
Measurement diameter: φ8mm
SCI/SCE: SCE (Excluded)
Color system: L*a*b*ΔE*ab
Field of view: 10°
Main light source: D65
Second light source: None Automatic white calibration: ON
The above L ^* , a ^* , and b ^* are arithmetic mean values of five consecutive measurements per point.

A “design” is a contoured figure or pattern formed by the “color difference” between one colored portion and a colored portion of a different color or an uncolored portion (having the color of the undyed fiber). The pattern is, for example, a striped pattern, a lattice pattern, or a geometric pattern consisting of straight contours such as them, a pattern having curved contours such as marble, characters, symbols, illustrations or photographs of animals, plants, or landscapes. When the outline of the pattern matches the outer shape of the fiber, for example, a melange tone made of a plurality of types of fibers with different degrees of dyeing is not a pattern.

The outer surface fiber layer of the artificial leather of this embodiment is colored continuously from the outer surface to a depth of 0.30 mm or more in the thickness direction in the colored portion. Since the outer surface fiber layer is continuously colored in the colored portion to a depth of 0.30 mm or more in the thickness direction from the outer surface, the outer surface is scraped by friction and the exposed wear surface has no uncolored fibers. It becomes the same pattern as the outer surface. In order for the outer surface fiber layer to be continuously colored in the colored portion from the outer surface to a depth of 0.30 mm or more in the thickness direction, for example, a method for increasing ink permeability during inkjet printing is adopted (described later). is preferred.
In addition, when the artificial leather whose entire artificial leather is colored with color A is provided with a colored portion with another color B, color B is continuously colored from the outer surface to a depth of 0.30 mm or more in the thickness direction. shall be required.
The thickness of the colored portion of the outer surface fiber layer of the artificial leather that is continuously colored from the outer surface is preferably 0.40 mm or more, more preferably 0.50 mm or more. Although the upper limit of the thickness of the outer surface fiber layer in which the outer surface fiber layer is colored continuously from the outer surface in the colored portion is not particularly defined, from the viewpoint of developing wear resistance and reducing the amount of ink (economic efficiency), it is 0.70 mm or less. is preferably

The average diameter of the ultrafine fibers forming the fiber layer in the colored portion on the outer surface of the artificial leather of the present embodiment is 2.0 μm or more and 4.5 μm or less. By setting the average diameter to 2.0 μm or more, the inter-fiber voids of the fiber layer constituting the artificial leather become an appropriate size, and the colorant more easily permeates from the outer surface in the thickness direction during inkjet printing. Excellent pattern retention. In addition, an artificial leather having good abrasion resistance, color development property by dyeing, and light fastness can be obtained. On the other hand, by setting the average diameter to 4.5 μm or less, the voids between the fibers of the fiber layer constituting the artificial leather are distributed more uniformly, and the colorant more uniformly permeates from the outer surface in the thickness direction during inkjet printing. , The uneven coloring of the worn surface of the outer surface scraped by friction is suppressed, and the pattern retention is excellent. In addition, since the number density of the fibers is high, an artificial leather having a high density, a smooth surface touch, and a better surface quality can be obtained. The average diameter of the ultrafine fibers forming the fiber layer in the colored portion of the outer surface of the artificial leather is preferably 2.0 μm or more and 4.3 μm or less, more preferably 2.0 μm or more and 4.1 μm or less.

Moreover, the thickness of the outer surface fiber layer of the artificial leather of the present embodiment is preferably 0.30 mm or more. When the thickness of the outer surface fiber layer is 0.30 mm or more, a sufficient number of ultrafine fibers constituting the outer surface fiber layer are entangled with each other, and the outer surface is less likely to be scraped by friction. The thickness of the outer surface fiber layer is more preferably 0.50 mm or more, still more preferably 0.70 mm or more. The thickness of the outer surface fiber layer is preferably 2.0 mm or less from the viewpoint of soft texture.

<Manufacturing method of artificial leather>
Another embodiment of the invention comprises the steps of:
(1) A step of forming a fiber web from ultrafine fibers having an average diameter of 2.0 μm or more and 4.5 μm or less;
(2) entangling the resulting fibrous web to obtain a fibrous sheet;
(3) optionally raising the outer surface of the obtained fiber sheet;
(4) filling the resulting fiber sheet with an elastic polymer to obtain a sheet;
(5) Raising the outer surface of the sheet material obtained in step (4) when step (3) is not performed;
(6) A step of continuously inkjet-printing the obtained sheet-like material to a depth of 0.30 mm or more in the thickness direction from the outer surface; and (7) reducing and washing the inkjet-printed sheet-like material. , obtaining a patterned artificial leather;
The method for producing a suede-like artificial leather according to any one of the above [1] to [4].
Each step will be described in order below.
In this specification, a fibrous web is defined as a nonwoven fabric made of fibers, a fibrous sheet is defined as a fiber web integrated by an entangling process, and a sheet-like material is defined as a fibrous sheet filled with an elastic polymer. Colored sheet material is distinguished from artificial leather. In addition, the fiber layer constituting the artificial leather is not limited to a single layer. For example, an artificial leather obtained using a fiber sheet obtained by integrating a three-layer structure laminate in which a fiber web, a scrim, and a fiber web are laminated in this order by an entangling process is composed of two fiber layers separated by a scrim. be done. Moreover, when the artificial leather includes two or more fiber layers, the structures are not limited to the same. For example, by configuring the fiber layer on the outer surface side with ultrafine fibers that are easy to obtain a smooth touch, and configuring the fiber layer on the opposite side of the outer surface with flame-retardant fibers that have a large diameter and are difficult to obtain a smooth touch. , it is possible to obtain an artificial leather imparted with flame retardancy while maintaining a smooth touch on the outer surface.

<Step of Forming Fiber Web from Fiber>
As a method for producing a fiber web of ultrafine fibers having an average diameter of 2.0 μm or more and 4.5 μm or less, a direct spinning method (for example, a spunbond method and a meltblown method) or a fiber web is formed using short fibers. methods (for example, dry methods such as carding method and airlaid method, and wet methods such as paper making method), all of which can be suitably used. In addition, the fiber web produced by the papermaking method using a raw material obtained by converting directly spun fibers into short fibers has small unevenness in basis weight, excellent uniformity, and is easy to obtain uniform raising, so the surface quality of artificial leather is improved. It is suitable in terms of improvement.

When a method using short fibers (staple) is selected, the short fiber length is preferably 13 mm or more and 102 mm or less, more preferably 25 mm or more and 76 mm or less, further preferably by a dry method (carding method, airlaid method, etc.). It is 38 mm or more and 76 mm or less, preferably 1 mm or more and 30 mm or less, more preferably 2 mm or more and 25 mm or less, still more preferably 3 mm or more and 20 mm or less by a wet method (paper making method or the like). The aspect ratio (L/D), which is the ratio of the length (L) to the diameter (D), of the short fibers used in wet processes (papermaking, etc.) is preferably 500 or more and 2000 or less, more preferably 700 or more. 1500 or less. Such an aspect ratio ensures good dispersibility and openability of the short fibers in the slurry when the short fibers are dispersed in water to prepare the slurry, and good strength of the fiber layer. Compared with the dry method, the fiber length is shorter and the single fibers are easily dispersed, so that it is less likely to cause a pilling appearance due to friction, which is preferable. For example, the fiber length of short fibers with a diameter of 4 μm is preferably 2 mm or more and 8 mm or less, more preferably 3 mm or more and 6 mm or less.

As the fibers constituting the fiber layer constituting the artificial leather, that is, the fibers constituting the fiber web, islands-in-the-sea composite fibers and fibers produced by a direct spinning method can be used. Fibers produced by a direct spinning method are preferable in that a fiber layer in which the fibers are dispersed as single fibers can be easily obtained.
Using ultra-fine fibers such as sea-island composite fibers (for example, copolyester as the sea component and regular polyester as the island component, etc.), fine fiber processing (dissolving the sea component of the sea-island composite fiber) , removal by decomposition, etc.) exist as fiber bundles in the fiber layer, and are not dispersed as single fibers. As an example, a sea-island composite staple fiber whose island component is equivalent to a single fiber fineness of 0.2 dtex and has 24 islands/1 f is prepared, and after forming a fiber web from the sea-island composite staple fiber, a fiber sheet is subjected to needle punching or the like. After filling the fiber sheet with PU resin, the sea component is dissolved or decomposed to obtain a sheet-like material composed of ultrafine fibers with a single fiber fineness equivalent to 0.2 dtex. In this case, 24 single fibers are present in the fiber layer in the state of a fiber bundle (equivalent to 4.8 dtex in the converged state).

In the present specification, the term "fibers are dispersed as single fibers" means that the fibers do not form fiber bundles such as the island component in the sea-island composite fiber. When the fiber layer is composed of fibers in which single fibers are dispersed, the surface smoothness is excellent, for example, the raising of the outer surface of the artificial leather raised by buffing or the like tends to be uniform, and the PU resin is used. Even when the adhesion rate of is relatively low, a pill-like appearance called pilling due to friction is less likely to occur, so an artificial leather having superior surface quality and abrasion resistance can be obtained. In addition, when the fibers are dispersed as single fibers, the spacing between the fibers is narrow and tends to be uniform. Less unevenness. As a method for dispersing fibers into single fibers, there is a method in which fibers manufactured by a direct spinning method are made into a fiber web by a papermaking method, and a method in which the sea component of a fiber sheet made of a sea-island composite fiber is dissolved or decomposed to form an ultrafine fiber bundle. After generating, the surface of the ultrafine fiber bundle is subjected to a water flow dispersion treatment to promote the formation of single fibers of the ultrafine fiber bundle.

<Step of Entangling Fiber Web to Obtain Fiber Sheet>
As an entangling method for integrating the fibrous web with the fibrous sheet, a hydroentangling treatment called a needle punching method or a spunlace method can be employed. By these entangling methods, one fiber sheet can be obtained from one fiber web. Laminates of webs may be consolidated to obtain a single fibrous sheet. In addition, for the purpose of increasing the mechanical strength such as the dimensional stability, tensile strength, tear strength, etc. of the fiber sheet and the artificial leather obtained using the fiber sheet, a laminate of one or more fiber webs and a scrim is integrated. to obtain a single fiber sheet. When the laminate is entangled, needle punching or hydroentangling treatment is preferably performed from both the outer surface side and the opposite side of the outer surface, since the peel strength between the fiber web and the scrim tends to increase. . Also, for example, in the case of a laminate having a three-layer structure in which a fibrous web, a scrim, and a fibrous web are laminated in this order, the entanglement treatment may be performed from both the outer surface side and the opposite side of the outer surface.

In the needle punch method, the number of barbs of the needle used is preferably 1-9. By setting the number of barbs to 1 or more, an entangling effect can be obtained and fiber damage can be suppressed. By setting the number of barbs to 9 or less, damage to the fibers can be reduced, and needle marks left on the artificial leather can be reduced, so that the appearance of the product can be improved.
Considering the entanglement of fibers and the effect on product appearance, the total depth of the barbs (the length from the tip of the barb to the bottom of the barb) is preferably 0.05 mm or more and 0.10 mm or less. When the total depth of the barbs is 0.05 mm or more, good hooking on the fibers can be obtained, and efficient fiber entangling becomes possible. Moreover, since the total depth of the barbs is 0.10 mm or less, needle marks remaining on the artificial leather are reduced, and the quality is improved. Considering the balance between the strength of the barb portion and the fiber entanglement, the total depth of the barb is more preferably 0.06 mm or more and 0.08 mm or less.
When fibers are entangled by a needle punch method, the range of punch density is preferably 300/cm ² or more and 6000/cm ² or less, and 1000/cm ² or more and 6000/cm ² or less. is more preferred.

When the fiber sheet is made of islands-in-the-sea composite fibers, for example, it is immersed in water at a temperature of 98° C. for 2 minutes to shrink, and dried at a temperature of 100° C. for 5 minutes to obtain a fiber sheet before sea removal. can.
The sea-removal treatment can be carried out by immersing the islands-in-the-sea fiber in a solvent and squeezing the solution. As a solvent for dissolving the sea component, an alkaline aqueous solution such as sodium hydroxide can be used when the sea component is copolyester or polylactic acid. From the viewpoint of environmental friendliness of the process, the sea removal treatment with an alkaline aqueous solution such as sodium hydroxide is preferred.
The hydroentanglement treatment is preferable in that it eliminates the risk of metal contamination caused by needle punching and can make the fiber sheet more dense. Moreover, when obtaining one fiber sheet from two or more fiber webs, the same fiber web may be used for the fiber webs.

The scrim can be, for example, a woven or knitted fabric, and is preferably made of the same polymer system as the fibers that make up the fiber layer of the artificial leather in terms of the same color when dyed. For example, if the fibers are polyester-based, the fibers forming the scrim are also preferably polyester-based, and if the fibers are polyamide-based, the fibers forming the scrim are also preferably polyamide-based. The scrim in the case of a knitted fabric is preferably a single knit knitted at 22 gauge or more and 28 gauge or less. If the scrim is a woven fabric, higher dimensional stability and strength can be achieved than a knitted fabric. The texture of the woven fabric may be a plain weave, a twill weave, a satin weave, or the like, but a plain weave is preferable from the viewpoint of cost and process aspects such as entanglement.

The threads that make up the fabric may be monofilaments or multifilaments. The monofilament fineness of the yarn is preferably 5.5 dtex or less in order to easily obtain a flexible artificial leather. As for the form of the yarn constituting the woven fabric, it is preferable to twist multifilament raw yarn such as polyester or polyamide, or textured yarn subjected to false twisting at a twist number of 0 to 3000 T/m. The multifilament may be a usual one, for example, 33dtex/6f, 55dtex/24f, 83dtex/36f, 83dtex/72f, 110dtex/36f, 110dtex/48f, 167dtex/36f, 166dtex/48f of polyester, polyamide, etc. It is preferably used. The threads that make up the woven fabric may be multifilament long fibers. The weaving density of the threads in the woven fabric is preferably 30 threads/inch or more and 150 threads/inch or less, more preferably 40 threads/inch or more and 100 threads/inch or less, in order to obtain an artificial leather that is flexible and has excellent mechanical strength. be. The basis weight of the woven fabric is preferably 20 g/m ² or more and 150 g/m ² or less in order to provide good mechanical strength and appropriate feel. In addition, the presence or absence of false twist processing in the fabric, the number of twists, the single fiber fineness of the multifilament, the weave density, etc., in addition to the entanglement with the constituent fibers of the fiber layer and the flexibility of the artificial leather, seam strength, tear strength, Since it also contributes to mechanical properties such as tensile strength and stretchability, it may be appropriately selected according to the target properties and application.

<Step of Raising Outer Surface of Fiber Sheet or Sheet-like Material (Step (3) or (5))>
In this step, a nap-raising treatment can be performed in order to form raised naps on the outer surface of the fiber sheet or sheet-like material. Raising treatment can be performed by a grinding method using sandpaper, a roll sander, or the like.
A lubricant such as a silicone dispersion may be applied to the fibrous sheet or sheet-like material prior to the raising treatment. By applying a lubricant such as a silicone dispersion to the fiber sheet or sheet-like material, it becomes possible to easily raise the surface by grinding, and the surface quality becomes very good. In addition, applying an antistatic agent before the raising treatment is a preferable mode for making it difficult for grinding dust generated from the fiber sheet or sheet-like material by grinding to accumulate on the sandpaper.

<Step of filling a fiber sheet with an elastic polymer to obtain a sheet-like article>
In this step, the fiber sheet can be filled with the elastic polymer in order to obtain a sheet-like article filled with the elastic polymer. Polyurethane (PU) resin is preferable as the polymeric elastic body, and it is easy to fill the fiber sheet with PU resin in a fine form, and even with a small amount of adhesion, it is easy to obtain the required performance as artificial leather such as texture and mechanical properties. Further, the water-dispersed PU resin is more preferable because it does not require the use of an organic solvent and can reduce the environmental load. That is, the water-dispersible PU resin can be impregnated into the fiber sheet in the form of a dispersion in which the PU resin is dispersed with a desired particle size. can be well controlled.

When a water-dispersible PU resin is used, a fiber sheet is impregnated with a PU resin dispersion and then dried to obtain a sheet-like article filled with the PU resin. In a typical embodiment, the PU resin is impregnated in the form of an impregnating liquid, such as a dispersion (eg, in the case of water dispersion). The concentration of the PU resin solid content in the impregnating liquid can be, for example, 3% by mass or more and 35% by mass or less. It is preferable to prepare the impregnation liquid and impregnate the fiber sheet so that the ratio of the PU resin to 100% by mass of the fiber sheet is 5% by mass or more and 50% by mass or less. When the ratio of the PU resin to 100% by mass of the fiber sheet is 5% by mass or more, the PU resin functions as a binder between the fibers, and the mechanical strength of the artificial leather can be easily obtained. In addition, by setting the ratio of the PU resin to 50% by mass or less with respect to 100% by mass of the fiber sheet, the PU resin tends to have an appropriate size, the penetration of the ink in inkjet printing is less likely to be hindered, and uneven coloring of the colored part is suppressed. be done. The ratio of the PU resin to 100% by mass of the fiber sheet is more preferably 5% by mass or more and 40% by mass or less, and still more preferably 5% by mass or more and 30% by mass or less.

[Water-dispersed polyurethane resin]
Water-dispersible PU resins are forcibly emulsified PU resins that are forcibly dispersed and stabilized using surfactants, and PU resins that have a hydrophilic structure in the PU molecular structure, and can be dispersed in water without the presence of surfactants. It is classified as a self-emulsifying PU resin that disperses and stabilizes in Although any of them may be used in the present embodiment, it is preferable to use a forced emulsification type PU resin from the viewpoint of imparting heat-sensitive coagulability, which will be described later.
Further, as the water-dispersed PU resin dispersion, one having heat-sensitive coagulability is preferable. By using a water-dispersed PU resin dispersion having heat-sensitive coagulability, the PU resin can be applied uniformly in the thickness direction of the fiber sheet. Heat-sensitive coagulability refers to the property of the PU resin dispersion to solidify when it reaches a certain temperature (heat-sensitive coagulation temperature) when it is heated. In the production of a sheet material filled with PU resin, after applying a PU resin dispersion to a fiber sheet, it is coagulated by dry heat coagulation, wet heat coagulation, hot water coagulation, or a combination thereof, and dried to form a fiber. The sheet is provided with PU resin. Dry heat coagulation is a practical method for coagulating water-dispersed PU resin dispersions that do not exhibit heat-sensitive coagulation in industrial production. occurs, and the texture of the sheet material filled with the PU resin tends to harden.

The thermal solidification temperature of the water-dispersed PU resin dispersion is preferably 40° C. or higher and 90° C. or lower. By setting the thermal solidification temperature to 40° C. or higher, the stability of the PU resin dispersion during storage is improved, and adhesion of the PU resin to the machine during operation can be suppressed. Further, by setting the thermal solidification temperature to 90° C. or lower, it is possible to suppress the migration phenomenon of the PU resin in the fiber sheet.
A coagulation accelerator may be added as appropriate to achieve the thermal coagulation temperature as described above. Examples of coagulation accelerators include inorganic salts such as sodium sulfate, magnesium sulfate, calcium sulfate, and calcium chloride, and radical reaction initiators such as sodium persulfate, potassium persulfate, ammonium persulfate, azobisisobutyronitrile, and benzoyl peroxide. agents.

A fiber sheet can be impregnated or coated with a water-dispersed PU resin dispersion, and the PU resin can be coagulated by dry heat coagulation, wet heat coagulation, hot water coagulation, or a combination thereof. The wet heat coagulation temperature should be equal to or higher than the thermal coagulation temperature of the PU resin, preferably 40° C. or higher and 200° C. or lower. By setting the wet heat solidification temperature to 40° C. or higher, more preferably 80° C. or higher, the time until the PU resin solidifies can be shortened, and the migration phenomenon can be further suppressed. On the other hand, by setting the wet heat solidification temperature to 200° C. or less, more preferably 160° C. or less, thermal deterioration of the PU resin can be prevented. The temperature for hot water coagulation is set to be equal to or higher than the thermosensitive coagulation temperature of the PU resin, preferably 40° C. or higher and 100° C. or lower. By setting the temperature for hot water solidification in hot water to 40° C. or higher, more preferably 80° C. or higher, the time until the PU resin solidifies can be shortened, and the migration phenomenon can be further suppressed. The dry heat coagulation temperature and the drying temperature are preferably 80°C or higher and 180°C or lower. By setting the dry heat coagulation temperature and the drying temperature to 80° C. or higher, more preferably 90° C. or higher, the productivity is excellent. On the other hand, by setting the dry heat coagulation temperature and drying temperature to 180° C. or less, more preferably 160° C. or less, thermal deterioration of the PU resin can be prevented.

A cross-linking agent can be used in combination with the water-dispersible PU resin for the purpose of improving durability such as resistance to moist heat, abrasion resistance, and hydrolysis resistance. It is preferable to add a cross-linking agent in order to improve the durability during liquid jet dyeing processing, suppress the shedding of fibers, and obtain excellent surface quality. The cross-linking agent may be an external cross-linking agent that is added as an additive component to the PU resin, or an internal cross-linking agent that previously introduces a reactive group capable of forming a cross-linked structure into the structure of the PU resin.
Water-dispersible PU resins used in artificial leather generally have a crosslinked structure to provide dyeing processing resistance, so they tend to be difficult to dissolve in organic solvents such as N,N-dimethylformamide. Therefore, for example, after the artificial leather is immersed in N,N-dimethylformamide at room temperature for 12 hours to dissolve the PU resin, when the cross section is observed with an electron microscope or the like, it is found to be resinous without a fiber shape. If the substance remains, it can be judged that the resinous substance is a water-dispersible PU resin.

The PU resin is preferably obtained by reacting a polymer diol, an organic diisocyanate and a chain extender.
Examples of polymer diols that can be used include polycarbonate-based, polyester-based, polyether-based, silicone-based, and fluorine-based diols, and copolymers in which two or more of these are combined may also be used. From the viewpoint of hydrolysis resistance, polycarbonate diols, polyether diols, or combinations thereof are preferably used. Moreover, from the viewpoint of light resistance and heat resistance, polycarbonate-based diols, polyester-based diols, or combinations thereof are preferably used. Furthermore, from the viewpoint of cost competitiveness, polyether diols, polyester diols, or combinations thereof are preferably used.
Polycarbonate-based diols can be produced by transesterification reaction between alkylene glycol and carbonate, reaction between phosgene or chloroformate and alkylene glycol, and the like.

Examples of alkylene glycol include direct glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol and 1,10-decanediol. chain alkylene glycols; branched alkylene glycols such as neopentyl glycol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-methyl-1,8-octanediol; Alicyclic diols such as 4-cyclohexanediol; aromatic diols such as bisphenol A;
Polyester-based diols include polyester diols obtained by condensing various low-molecular-weight polyols and polybasic acids.
Examples of low molecular weight polyols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,2-dimethyl-1,3-propane, Diol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, cyclohexane-1,4-diol, cyclohexane One or more selected from -1,4-dimethanol can be used. Adducts obtained by adding various alkylene oxides to bisphenol A can also be used.
Examples of polybasic acids include succinic acid, maleic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, and hexahydro One or two or more selected from the group consisting of isophthalic acid can be mentioned.

Polyether-based diols include, for example, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and copolymerized diols in which these are combined.
The number average molecular weight of the polymer diol is preferably 500 or more and 4000 or less. By setting the number average molecular weight to 500 or more, more preferably 1500 or more, it is possible to prevent the texture from becoming hard. Further, by setting the number average molecular weight to 4000 or less, more preferably 3000 or less, the strength of the PU resin can be maintained satisfactorily.
Examples of organic diisocyanates include aliphatic diisocyanates such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate and xylylene diisocyanate; aromatic diisocyanates such as diphenylmethane diisocyanate and tolylene diisocyanate; may be used. Among them, aliphatic diisocyanates such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, and isophorone diisocyanate are preferably used from the viewpoint of light resistance.
As the chain extender, an amine-based chain extender such as ethylenediamine and methylenebisaniline, or a diol-based chain extender such as ethylene glycol can be used. A polyamine obtained by reacting a polyisocyanate with water can also be used as a chain extender.

The impregnating liquid containing PU resin (for example, water-dispersed PU resin) may optionally contain stabilizers (ultraviolet absorbers, antioxidants, etc.), flame retardants, antistatic agents, pigments (carbon black, etc.), etc. Additives may be added. The total amount of these additives present in the artificial leather is, for example, 0.1 parts by mass or more and 10.0 parts by mass or less, or 0.2 parts by mass or more and 8.0 parts by mass or less with respect to 100 parts by mass of the PU resin. , or 0.3 parts by mass or more and 6.0 parts by mass or less. Such additives are distributed in the PU resin of the artificial leather. In this disclosure, values when referring to PU resin size and mass ratio to fiber sheet are intended to include additives (if used).

<Step of continuous inkjet printing on a sheet-like material to a depth of 0.30 mm or more in the thickness direction from the outer surface>
The outer surface of the artificial leather of this embodiment is colored for the purpose of enhancing the value of the sensory aspect (that is, the visual effect). The colorant may be selected according to the type of fibers that make up the fiber sheet. For example, disperse dyes can be used for polyester fibers, and acid dyes and metallized dyes are used for polyamide fibers. can be used, and combinations thereof can be used. In the case of dyeing with a disperse dye, reduction cleaning may be performed after dyeing. As a dyeing method, a conventional method well known to dyeing processors can be used. As a dyeing method, a jet dyeing machine can be used because the sheet-like material can be softened by giving a kneading effect at the same time as dyeing the sheet-like material, but any pattern can be applied to the outer surface of the artificial leather. Inkjet printing is preferred because it can be applied. Ink jet printing can be performed using an ink jet printer.

The ink used for inkjet printing may contain at least a dye as a colorant. The ink is prepared to have a predetermined color by blending a coloring agent.

As the dye, disperse dyes are preferable from the viewpoint of excellent color developability and light resistance. Specific examples of disperse dyes include, for example, benzeneazo dyes (monoazo, disazo, etc.), heterocyclic azo dyes (thiazolazo, benzothiazoleazo, quinolineazo, pyridineazo, imidazoleazo, thiophenazo, etc.), anthraquinone dyes, and condensation dyes. dyes (quinophthalin, styryl, coumarin, etc.) and the like.

Further, in inkjet printing, it is preferable to pretreat the outer surface of the sheet-like material with a pretreatment agent before inkjet printing. By applying the pretreatment, bleeding of the dye can be suppressed, making it easier to form a sharp pattern, and a pattern with high density and clear colors can be printed.

Examples of pretreatment agents include water-soluble polymers, anti-reduction agents, pH adjusters, and polyvalent metal salts. Specific examples of water-soluble polymers include sodium alginate, locust bean, modified starch, and carboxymethylcellulose (CMC). Specific examples of anti-reduction agents include sodium m-nitrobenzenesulfonate and sodium chlorate. Specific examples of pH adjusters include malic acid, citric acid, tartaric acid, sodium monophosphate, and the like. Specific examples of polyvalent metal salts include aluminum sulfate, aluminum chloride, magnesium sulfate, barium chloride, and the like. In addition, it is not limited to the above, and as an anti-bleeding agent, diallyldimethylammonium chloride polymer, N-aziridyl-N'-alkyl urea, wax, chelating agent, dispersant, polyhydric alcohol such as polyglycerin, etc. may also include Further, the pretreatment agent may be an aqueous solution or dispersion liquid using water as a solvent, or an emulsion (half emulsion) using turpentine or the like.

Prior to inkjet printing, the sheet may be washed using a jet dyeing machine. By washing the sheet material using a jet dyeing machine, organic substances and inorganic salts that are undesirable to remain in the product can be removed, and the artificial leather can be easily softened by the kneading effect. The washing of the sheet-like material using the jet dyeing machine can be performed with water, but for example, in order to impart performance such as flame retardancy, chemicals or auxiliary agents may be added to the water. good.

For the purpose of coloring the fiber layer from the outer surface of the artificial leather to an arbitrary depth, a method of increasing ink permeability during inkjet printing may be employed. As the method, for example, a method of penetrating the ink by suctioning negative pressure from the opposite side of the printing surface of the base material in the ink ejection section of the inkjet printer can be used.

After inkjet printing, the ink is preferably fixed to the substrate by drying. When an ink containing a disperse dye is used as a colorant, after fixing the ink to the base material, the base material may be heated with dry heat or wet heat to diffuse and fix the disperse dye inside the base material. preferable.

<Step of obtaining artificial leather by reducing and washing the inkjet-printed sheet-like material>
Artificial leather filled with polyurethane resin is preferably subjected to soaping and optionally reduction washing (ie washing in the presence of a chemical reducing agent) to remove excess dye.
When the artificial leather is colored or dyed using an inkjet printer, it is preferable to perform soaping and, if necessary, reduction washing with a jet dyeing machine. Carrying out reduction washing with a liquid jet dyeing machine has the advantage of being able to efficiently remove organic substances and inorganic salts that are not desirable to remain in the product together with washing, and the fact that it is easy to achieve softening of artificial leather due to the rubbing effect. is preferred.

[Artificial leather]
When the artificial leather of the present embodiment is composed of only a single fiber layer (outer surface fiber layer), the fabric weight of the fibers constituting the fiber layer is preferably 40 g/ m ² or more and 500 g/m ² or less, more preferably 50 g/m ² or more and 370 g/m ² or less, still more preferably 60 g/m ² or more and 320 g/m ² or less.
When the artificial leather is composed of a three-layer structure in which a fiber layer, a scrim, and a fiber layer are laminated in this order, the fabric weight of the fibers constituting the outer surface fiber layer is preferably 10 g/m ² or more and 200 g/m ² or less, more preferably 30 g/m ² or more and 170 g/m ² or less, and still more preferably 60 g/m ² or more and 170 g/m ² or less. In addition, the basis weight of the fibers constituting the fiber layer on the side opposite to the outer surface is preferably 10 g/m ² or more and 200 g/m ² or less, more preferably 20 g/m ² from the viewpoint of cost and ease of production. It can be set to 170 g/m 2 or more and 170 g/m ² or less. The basis weight of the scrim is preferably 20 g/m ² or more and 150 g/m 2 or less, more preferably 20 g/m ² or ^more and 130 g/m ² or less, still more preferably, from the viewpoint of mechanical strength and entanglement between the fiber layer and the scrim. is 30 g/m ² or more and 110 g/m ² or less.
The PU resin-filled artificial leather has a basis weight of preferably 50 g/m ² or more and 550 g/m ² or less, more preferably 60 g/m ² or more and 400 g/m ² or less, and still more preferably 70 g/m ² or more and 350 g/m 2 or more. ² or less.

[Flexibility value]
The artificial leather preferably has a stiffness value of 28 cm or less. When the stiffness value of the artificial leather is 28 cm or less, it tends to have a soft texture. The stiffness value of the artificial leather is more preferably 27 cm or less, more preferably 26 cm or less. Although there is no particular lower limit for the stiffness and flexibility of the artificial leather, it is preferably 20 cm or more from the viewpoint of mechanical strength.

The artificial leather of this embodiment can be used as a surface material for furniture, chairs, wall materials, seats in vehicles such as automobiles, trains, aircraft, ceilings, interiors, etc. Interior materials, shirts, jackets, casual Shoes, sports shoes, men's shoes, women's shoes, uppers, trims, etc., bags, belts, wallets, etc., clothing materials used for some of them, industrial materials such as wiping cloths, polishing cloths, CD curtains, etc. It can also be suitably used as

EXAMPLES The present invention will be specifically described below based on examples and comparative examples, but the examples do not limit the scope of the present invention. For the artificial leather samples using the fiber sheets according to Examples and Comparative Examples, each physical property, quality, etc. were evaluated and judged using the following procedures and methods.

(1) Thickness of artificial leather The thickness of artificial leather is measured by randomly selecting 4 points separated by 5 cm or more from each other with a thickness measuring instrument ("PEACOCK MODEL-H" manufactured by Ozaki Seisakusho). Average value.

(2) Depth of the Colored Portion in the Thickness Direction of the Cross Section of the Artificial Leather Ten regions including the outer surface to the boundary of the colored portion are randomly selected from the thickness direction cross section of the artificial leather. The 10 regions are photographed at a magnification of 50 using a microscope (Keyence "VHX-950F") so that the long side of the image is parallel to the surface direction of the artificial leather, and 10 images are obtained. For each of the 10 images, as shown in FIG. 1, 9 line segments parallel to the short sides of the image are drawn on each image so that each image is divided into 10 equal parts. Visually determine the boundary between the colored portion and the non-colored portion on each line segment, determine the distance L on the line segment from the boundary to the outer surface, and calculate the nine distances L per image Calculate the average value. From the arithmetic average values of the 10 images, the arithmetic average value is calculated and taken as the depth of the colored portion in the thickness direction in the cross section of the artificial leather.

(3) Average diameter (μm) of fibers constituting the outer surface fiber layer
The average diameter of the fibers that make up the outer surface fiber layer is obtained by photographing a cross section in the thickness direction of the artificial leather at a magnification of 1500 using a scanning electron microscope (SEM, "JSM-5610" manufactured by JEOL Ltd.). 100 fibers constituting the outer surface fiber layer of the artificial leather are randomly selected from one captured image, the cross-sectional diameter of the single fiber is measured, and the arithmetic mean value of the measured values of 100 fibers is obtained.
When the observation shape of the cross section of the single fiber is not circular, the fiber diameter is the distance between the outer circumferences on a straight line perpendicular to the midpoint of the longest diameter of the single fiber cross section.
FIG. 2 is a conceptual diagram explaining how to obtain the fiber diameter. For example, when the cross section A of the fiber is elliptical as shown in FIG. 2, the fiber diameter is defined as the distance c between the outer circumferences on a straight line b perpendicular to the midpoint p of the longest diameter a of the cross section A in the observed image.

(4) Pattern Retention of Abraded Surface of Artificial Leather Outer Surface by Friction From the colored portion of the outer surface of artificial leather, select any two regions having similar patterns. Cut out a sample containing one region of them, Martindale test (testing machine: James H. Heal "New Martindale abrasion tester (model: 1609 (9 pieces)) wear cloth: James H. Heal "ABRASIVE CLOTH1575W") to obtain a sample containing a wear surface scraped by friction. The conditions for the Martindale test are as follows.
Sample basis weight 200 g/m ² or more: 20,000 friction times, load 12 kPa
Sample basis weight less than 200 g/m ² : 20,000 rubbing times, load 9 kPa.
Next, a total of 20 evaluators, 10 adult males and 10 adult females in good health, were used to evaluate the design of the worn surface of the sample compared with another area that was not used for the sample, visually and sensory. By evaluation, it is judged in five stages according to the following evaluation criteria. The design retention of the worn surface of the artificial leather that has been scraped by friction is judged to be good (acceptable) if it is in the range of 3.0 to 5.0.
[Evaluation criteria]
Grade 5: The pattern on the worn surface is visible.
Grade 4: A rating between grades 5 and 3.
Grade 3: The pattern on the worn surface is slightly visible.
Grade 2: An evaluation between Grade 3 and Grade 1.
Grade 1: The pattern on the worn surface cannot be visually recognized.
Even if the pattern on the worn surface remains, if the fibers are significantly dropped or the pilling is remarkable, and the surface quality is not preferable, it is out of the grade.
In addition, the value obtained by rounding off the arithmetic average value of the evaluation results of the above 20 persons for one sample is taken as the grade of the design retention of the worn surface of the outer surface of the artificial leather that has been scraped by friction.

(5) Calculation of stiffness value A sample is cut into a square of 20 cm x 20 cm and used as a measurement sample. A measurement sample is placed on a horizontal plane, and apexes A, B, C, and D of a square are placed on top of each other and apexes A and C facing each other on a diagonal line are superimposed. Vertex A is placed on a horizontal plane, vertex C is superimposed on vertex A, then vertex C is gradually moved away from vertex A along diagonal line AC while in contact with the measurement sample, and vertex C is the measurement sample surface. A point away from is defined as a point E, and the distance between the point E and the vertex C is defined as a stiffness value of 1. The stiffness value 2 is measured in the same manner as described above, replacing the vertex A with the vertex B and the vertex C with the vertex D, respectively. The arithmetic average value of stiffness value 1 and stiffness value 2 is taken as the stiffness value of the sample. When the artificial leather is a single layer, the average value of 10 samples is taken as the texture (flexibility value). When the artificial leather has a structure of two or more layers, 5 samples measured with the outer surface fiber layer of the artificial leather facing up, and 5 samples measured with the fiber layer on the opposite side of the outer surface facing up. The average value for is taken as the stiffness value of the sample.

[Base material A-1]
A polyethylene terephthalate fiber with an average single fiber diameter of 3.9 μm was produced by a melt spinning method and cut into 5 mm lengths (hereafter, polyethylene terephthalate fibers with an average single fiber diameter of 4 μm cut into 5 mm lengths are referred to as “PET (Also known as ultra-fine short fibers.) The PET ultrafine short fibers were dispersed in water and a fiber web having a basis weight of 140 g/m ² was produced by a papermaking method, which was used as the outer surface fiber layer.
In the same manner, PET ultrafine short fibers were dispersed in water to produce a fiber web having a basis weight of 60 g/m ² by a papermaking method, and this was used as the fiber layer on the opposite side of the outer surface.
A scrim (plain weave fabric) of 166 dtex/48 f polyethylene terephthalate fibers with a basis weight of 95 g/m ² was inserted between the outer surface fiber layer and the fiber layer on the opposite side of the outer surface to form a three-layer laminate.
Next, a high-speed water jet using a straight jet nozzle is jetted to the three-layer laminate at a pressure of 4 MPa from the outer surface side and 3 MPa from the opposite side of the outer surface to entangle the fiber layers into a scrim. After being entangled and integrated, it was dried at 100° C. using an air-through type pin tenter dryer to obtain a fiber sheet having a three-layer structure.
Next, the outer surface of the fiber sheet was raised using #400 emery paper.
Subsequently, the fiber sheet was impregnated with a water-dispersed polyurethane resin impregnating solution shown in Table 1 below, dried by heating at 130°C using a pin tenter dryer, and then immersed in hot water heated to 90°C. After drying, anhydrous Glauber's salt was extracted and removed to obtain a sheet material filled with a water-dispersed polyurethane resin as a substrate A-1. The ratio of the water-dispersible PU resin to the total mass of fibers in this sheet was 10% by mass.

[Base material A-2]
The average diameter of the single fibers used in the fiber web is 3.2 μm, the fabric weight of the fiber web constituting the outer surface fiber layer is 80 g/m ² , and the fabric weight of the spine constituting the fiber layer on the opposite side of the outer surface is 30 g. A sheet-like product was obtained as a substrate A- ² in accordance with the method described for the substrate A-1, except that the basis weight was 1/m 2 . The ratio of the water-dispersible PU resin to the total mass of fibers in this sheet was 10% by mass.

[Base material A-3]
A sheet-like material was obtained as a substrate A-3 in accordance with the method described for the substrate A-1, except that the average diameter of the single fibers used in the fiber web was 4.8 μm. The ratio of the water-dispersible PU resin to the total mass of fibers in this sheet was 10% by mass.

[Base material A-4]
A gray sheet was used as the base material A-4 in accordance with the method described for the base material A-1, except that the water-dispersed polyurethane resin impregnation liquid for impregnating the fiber sheet contained the pigments shown in Table 2 below. I got something. The ratio of the water-dispersible PU resin to the total mass of fibers in this sheet was 10% by mass.

[Base material B-1]
Polyethylene terephthalate obtained by copolymerizing 8 mol% of sodium 5-sulfoisophthalate is used as the sea component, and polyethylene terephthalate is used as the island component. A sea-island composite fiber having 16 islands/1 f and an average fiber diameter of 18 μm was obtained. The obtained islands-in-the-sea composite fiber was cut into a fiber length of 51 mm, stapled, passed through a card and a cross wrapper to form a fiber web, and needle-punched to obtain a fiber sheet. The resulting fiber sheet was immersed in hot water at 95° C. to shrink and dried at 100° C. for 5 minutes using the pin tenter dryer to obtain a single-layer fiber sheet with a basis weight of 600 g/m ² .
The resulting fiber sheet was immersed in an aqueous sodium hydroxide solution with a concentration of 10 g/L heated to 95° C. for 25 minutes to remove the sea component from the islands-in-sea composite fiber. The average diameter of single fibers constituting the fiber sheet after sea removal was 3.9 μm.
Next, the fiber sheet is impregnated with a water-dispersed polyurethane resin impregnating solution shown in Table 3 below, and wet-heat coagulated at 100° C. for 5 minutes, and then dried at 130° C. to 150° C. for 2 to 6 minutes using a pin tenter dryer. It was dried with hot air.
Thereafter, the sheet was immersed in hot water heated to 95° C. to extract and remove the impregnated anhydrous sodium sulfate, thereby obtaining a sheet-like article filled with the water-dispersible PU resin. The ratio of the water-dispersible PU resin to the total mass of fibers in this sheet was 30% by mass.
Then, using a halving machine having an endless band knife, the sheet material was halved perpendicularly to the thickness direction, and the non-halved surface was raised using #400 emery paper. As No. 1, a sheet material having a basis weight of 330 g/m 2 was obtained.

[Base material B-2]
A sheet-like material was obtained as a base material B-2 in accordance with the method described for the base material B-1, except that the basis weight of the sheet-like material after being cut in half was adjusted to 150 g/m ² . The ratio of the water-dispersible PU resin to the total mass of fibers in this sheet was 30% by mass.

[Base material B-3]
Substrate B was prepared according to the method described in Substrate B-1, except that a sea-island composite fiber having an average single fiber diameter of 2.5 μm was used for the fiber web. A sheet was obtained as -3. The ratio of the water-dispersible PU resin to the total mass of fibers in this sheet was 30% by mass.

[Base material B-4]
Substrate B was prepared according to the method described in Substrate B-1, except that sea-island composite fibers having an average single fiber diameter of 1.0 μm were used for the fiber web. A sheet was obtained as -4. The ratio of the water-dispersible PU resin to the total mass of fibers in this sheet was 30% by mass.

[Inkjet printing (penetration means: suction)]
The substrate was immersed in a bath filled with a pretreatment agent (CMC, polyacrylic acid, polyglycerin, water mixture) and dried at 120° C. for 3 minutes. Next, using an inkjet printing machine ("MonnaLisa" manufactured by Seiko Epson), the dye is set, and the opposite side of the outer surface of the substrate is printed from the slit of the suction box directly below the inkjet ejection unit and connected to the suction pump. Ink jet printing was applied to the outer surface of the substrate while the side was being sucked at −5 kPa to obtain a printed surface on which the pattern A shown in FIG. 3 was spread as a repeating unit. Next, by reduction washing using a liquid jet dyeing machine, unfixed dyes, organic substances and inorganic salts that are not desirable to remain in the product are removed, and the soft cloth is made by rubbing effects, and then dried to create an arbitrary pattern. was printed on the outer surface of the artificial leather.

[Inkjet printing (penetration means: none)]
The substrate was immersed in a bath filled with a pretreatment agent (CMC, polyacrylic acid, polyglycerin, water mixture) and dried at 120° C. for 3 minutes. Next, using an inkjet printer ("MonnaLisa" manufactured by Seiko Epson), a dye is set and inkjet printing is performed on the outer surface of the base material to obtain a printed surface on which the pattern A shown in FIG. 3 is spread as a repeating unit. rice field. Next, by reduction washing using a liquid jet dyeing machine, unfixed dyes, organic substances and inorganic salts that are not desirable to remain in the product are removed, and the soft cloth is made by rubbing effects, and then dried to create an arbitrary pattern. was printed on the outer surface of the artificial leather.

[Example 1]
The substrate A was colored according to the method of ink-jet printing (permeation means: suction), and an artificial leather printed with pattern A shown in FIG. 3 as a repeating unit spread over the printed surface was obtained. The evaluation results are shown in Table 4 below.

[Examples 2 to 5, Comparative Examples 1 to 5]
An artificial leather having a pattern A printed on the surface was obtained in the same manner as in Example 1 except that the base material and permeation means (suction or none) shown in Table 4 below were used. The evaluation results are shown in Table 4 below.

From the above results, in each example, compared to the general dyeing method, the design is excellent, the uncolored fibers on the worn surface are less exposed, and the uneven coloring on the worn surface is small. It can be seen that an excellent artificial leather was obtained.

The artificial leather obtained by the method for producing artificial leather according to the present invention has excellent design properties and excellent pattern retention compared to general dyeing methods, so it can be used for interiors, automobiles, aircraft, railway vehicles, etc. It can be suitably used for furnishing products such as sheet covering materials or interior materials. Specifically, the artificial leather according to the present invention can be used as a surface material for furniture, chairs, wall materials, seats, ceilings, and interiors in vehicles such as automobiles, trains, and aircraft. Shirts, jackets, casual shoes, sports shoes, men's shoes, women's shoes uppers, trims, etc., bags, belts, wallets, etc. Clothing materials used for some of them, wiping cloths, polishing cloths, CD curtains It can be suitably used as an industrial material such as.

L _i Distance from the boundary of the colored part to the outer surface in the cross section in the thickness direction of the artificial leather ( _i = 1 to 9)
A Cross section of fiber a Longest diameter P Middle point of longest diameter a b Straight line perpendicular to a at P c Distance between outer circumferences on b (fiber diameter)

Claims (5)

A suede-like artificial leather having a brushed appearance that includes at least an outer surface fiber layer that constitutes the outer surface and a polymeric elastic body,
The outer surface has at least one colored portion,
The outer surface has a pattern composed of the colored portion,
In the colored portion, the outer surface fiber layer is colored continuously from the outer surface to a depth of 0.30 mm or more in the thickness direction, and
A suede-like artificial leather, wherein the outer surface fiber layer is composed of ultrafine fibers having an average diameter of 2.0 μm or more and 4.5 μm or less. The suede-like artificial leather according to claim 1, wherein said ultrafine fibers are polyester fibers. The suede-like artificial leather according to claim 1 or 2, having a stiffness value of 28 cm or less. The suede-like artificial leather according to any one of claims 1 to 3, wherein the suede-like artificial leather is a sheet-like material composed of two or more layers including at least a woven or knitted scrim and the outer surface fiber layer. leather. The following steps:
(1) A step of forming a fiber web from ultrafine fibers having an average diameter of 2.0 μm or more and 4.5 μm or less;
(2) entangling the resulting fibrous web to obtain a fibrous sheet;
(3) optionally raising the outer surface of the obtained fiber sheet;
(4) filling the resulting fiber sheet with an elastic polymer to obtain a sheet;
(5) Raising the outer surface of the sheet material obtained in step (4) when step (3) is not performed;
(6) A step of continuously inkjet-printing the obtained sheet-like material to a depth of 0.30 mm or more in the thickness direction from the outer surface; and (7) reducing and washing the inkjet-printed sheet-like material. , obtaining a patterned artificial leather;
The method for producing a suede-like artificial leather according to any one of claims 1 to 4, comprising.

Images