JP5540731B2 - Artificial leather and method for producing the same - Google Patents

Description

  The present invention relates to an artificial leather that not only has high strength and excellent shape stability but also has little napped fiber density unevenness and a method for producing the same.

  Artificial leather has been used for various purposes such as a veneer for vehicle seats, interiors, shoes, bags and gloves. Among them, artificial leather used for vehicle seat overlays and interiors is composed of woven and knitted fabrics, non-woven fabrics made of ultrafine fibers, and polymer elastic bodies in order to obtain form stability and high strength. Various methods have been proposed for the specific manufacturing method.

  The general manufacturing method of these artificial leather is as follows. After making ultrafine fibers or composite fibers that can be made ultrafine into a web, woven or knitted fabric is laminated on them, and the fibers are entangled by needle punching or water jet punching with a high-speed fluid to remove one component in the composite fibers and remove ultrafine fibers. There is known a method of obtaining a flexible artificial leather by imparting an elastic polymer such as polyurethane to the obtained sheet base after the conversion.

  In particular, the needle punch method can be strongly entangled between the nonwoven fabric and the woven fabric compared to the water jet punch method with a thin entangled effect inside the sheet substrate, while the woven fabric is caught and damaged by the needle needle barb, Physical properties and quality, such as a decrease in physical property improvement effect and single yarns that make up a fabric with a different fineness from the ultrafine fibers that form the nonwoven fabric layer protrude from the surface of the artificial leather with a needle punch, making the artificial leather feel rough and hard. There was a problem that should be improved.

  Against this background, a method has been proposed in which the number of twists of the warp and weft constituting the woven fabric is set to 700 T / m or more, and the single yarn constituting the woven fabric is not easily caught by the needle needle barb and the texture is not hardened. (See Patent Document 1).

  Also proposed is a method of reducing the roughness of the tactile sensation due to the exposure of the fibers constituting the fabric, by setting the single fiber fineness of the single yarn constituting the fabric to 0.05 denier or more and 5.0 denier or less and making it an ultrafine fiber. (See Patent Document 2). However, the above-mentioned method regulates the structure of the woven fabric to suppress the damage and exposure to the surface of the woven fabric and eliminate the defects. However, the density of napped fibers greatly affects the tactile feel of the surface in artificial leather. No method has been proposed for eliminating the unevenness.

  In addition, as a method for improving the napped fiber density, the fiber density on the sheet surface is increased by the strong shrinkage force of the woven or knitted fabric, and then the woven or knitted fabric is peeled off to obtain a dense and high-grade quality and a good touch. Has been proposed (see Patent Document 3). However, in artificial leather in which a nonwoven fabric and a woven or knitted fabric are intertwined and integrated, due to the difference in shrinkage between the nonwoven fabric and the woven or knitted fabric, there is a means to achieve a textured surface quality and excellent quality of the artificial leather. The current situation is that it has not been issued.

JP 2001-164475 A JP-A-5-132878 JP 2003-13368 A

  The object of the present invention is not only the conventional high-strength and excellent shape stability, but also fiber density unevenness in an artificial leather in which an elastic polymer is applied as a binder to a non-woven fabric made of ultrafine fibers and a sheet substrate made of woven fabric. An object of the present invention is to provide an artificial leather having a small flat feeling.

  As a result of intensive investigations to achieve the above-mentioned problems, the inventors of the present invention have decided to use ultrafine fiber bundles in order to suppress the napped fiber density unevenness that contributes to the feeling of high-quality napped surfaces unique to artificial leather and lighting effects. The present inventors have found that it is important to suppress the shrinkage rate of an artificial leather base sheet in a finishing process such as dyeing after applying an elastic polymer to be captured.

That is, the artificial leather of the present invention is the artificial leather in which an elastic polymer is applied as a binder to a non-woven fabric composed of ultrafine fibers and a sheet substrate composed of a woven fabric, and the above-mentioned fabric difference between overlapping heights of adjacent twist cross sections of the fabric. The artificial leather is characterized in that the quotient of the twisted yarn diameter is 0.25 or less.

In addition, a method for producing artificial leather obtained by dyeing an artificial leather base sheet in which an elastic polymer is added as a binder to a sheet substrate obtained by intertwining and integrating a nonwoven fabric composed of ultrafine fibers according to the present invention. , as the fabric, using a 120 ° C. fabric area shrinkage ratio is less than 10% 1% at a temperature of, controlling the shrinkage ratio in the artificial leather base sheet of the dyeing process such that 14% or less than 1% it is a manufacturing method of artificial leather shall be the feature to be. That is, the shrinkage of the artificial leather base sheet is suppressed in the dyeing step after the binder is applied so that the quotient of the overlapping heights of adjacent twisted yarn cross sections of the fabric and the twisted yarn diameter of the fabric is 0.25 or less.

In addition, a method for producing artificial leather obtained by dyeing an artificial leather base sheet in which an elastic polymer is added as a binder to a sheet substrate obtained by intertwining and integrating a nonwoven fabric composed of ultrafine fibers according to the present invention. is a method for producing artificial leather you characterized in that through the at least the following I~III steps.
I. A short fiber web made of ultrafine fiber-generating fibers and a woven fabric having an area shrinkage of 1% to 10% at a temperature of 120 ° C. are laminated, and the nonwoven fabric and the woven fabric are intertwined and integrated by a needle punching process. Obtaining a sheet substrate.
II. After removing the elution component of the ultrafine fiber generating fiber of the sheet base obtained in the step I, the polymer elastic body is applied, or after the polymer elastic body is applied, the elution component of the ultrafine fiber generating fiber is added. The process of obtaining the artificial leather base sheet before the dyeing process ground and raised by sandpaper after removing.
III. A step of obtaining artificial leather by performing fluid flow dyeing on the artificial leather base sheet obtained in Step II and controlling the shrinkage before and after dyeing to be 1 % or more and 14% or less.

  According to the present invention, it is possible to obtain an artificial leather having not only high strength and excellent shape stability, but also a flat feeling with little uneven napped fiber density on the surface. Furthermore, according to the present invention, since the napped fiber density becomes uniform, it is possible to impart a uniform feeling to the color of the product.

FIG. 1 is a drawing-substituting photograph for explaining a method of measuring a difference in height where adjacent twisted yarn cross sections overlap. FIG. 2 is a drawing-substituting photograph showing the surface of the artificial leather obtained in the present invention (Example 1). FIG. 3 is a drawing-substituting photograph showing the surface of the artificial leather obtained in Comparative Example 1.

  The artificial leather of the present invention is an artificial leather composed of a sheet substrate in which a nonwoven fabric mainly composed of ultrafine fibers and a woven fabric are intertwined and an elastic polymer, and has less distortion of fibers constituting the fabric in the artificial leather. .

The artificial leather of the present invention is an artificial leather in which an elastic polymer is applied as a binder to a non-woven fabric composed of ultrafine fibers and a sheet substrate composed of a woven fabric, as will be described later. By suppressing the shrinkage of the material sheet, the quotient of the overlapping height difference between adjacent twist cross sections of the fabric and the twist yarn diameter of the fabric is set to 0.25 or less. The shrinkage before and after dyeing is controlled to be 1 or more and 14% or less.

In the present invention, in order to make the quotient of the overlapping height difference of adjacent twisted yarn cross sections of the woven fabric and the twisted yarn diameter of the woven fabric less than 0.25, the artificial leather base sheet is subjected to liquid dyeing and dyeing as described later. Control is performed so that the contraction rate before and after becomes 1 to 14%.

The fabric used for the artificial leather of the present invention has a dry heat shrinkage rate of 1% to 10% at a temperature of 120 ° C. in order to suppress distortion of the sheet substrate due to shrinkage of the fabric after application of the elastic polymer. Thus, it is important to adjust the weave density, the twisted yarn diameter, the single fiber fineness, the number of twists, and the like of the fibers constituting the twisted yarn, which are related to the shrinkage rate of the fabric.

  The single yarn constituting the woven fabric used for the artificial leather of the present invention includes a single yarn made of a synthetic fiber such as a polyester fiber or a polyamide fiber, but it may be the same material as the ultrafine fiber in terms of dyeing fastness. preferable. Examples of the form of the single yarn include filament yarn and spun yarn, and preferably these strong twisted yarns are used. In addition, filament yarn is preferably used for the spun yarn because it causes surface fluff to fall off.

When using a strongly twisted yarn, the number of twists is preferably 1000 T / m or more and 4000 T / m or less, more preferably 1500 T / m or more and 3500 T / m or less. When the number of twists is less than 1000 T / m, the number of single fibers constituting the twisted yarn by needle punching increases, and the physical properties of the product tend to deteriorate and the single fibers are exposed to the product surface. Moreover, when the number of twists is greater than 4000 T / m, the single fiber breakage can be suppressed, but the twisted yarn constituting the woven fabric becomes too hard, and thus tends to cause hardening of the texture . Further, by increasing the number of twists, not only suppress shrinkage in the longitudinal direction of the whole twisted yarn constituting the fabric due to shrinkage of the twisting, aspect ratio twisted yarn is reduced, the friction weft intersections of the fabric is reduced Thus, the shrinkage rate of the fabric can be suppressed.

The diameter of the twist yarn is preferably not 100μm or 200μm or less, more preferably 120μm or more 180μm or less. And 100μm smaller than the diameter of the yarn twist, distortion of the fabric when contraction in the dyeing process is increased. Also shows the diameter of the thread is greater than 200μm twisting, but is suppressed in distortion of the fabric in the dyeing process, the entangled nonwoven webs and woven fabrics by the needle punching is insufficient, tends to form stability of the product is reduced .

Single fiber fineness of the fibers constituting the twisted yarn, 3.5 dtex or less are preferred over 0.01 dtex, more preferably not more than 1.0dtex than 0.1 dtex. By reducing the fineness of the single fiber, the shrinkage stress generated in one single fiber of the fabric at the time of shrinkage in the dyeing process is reduced, and the entire sheet base due to the shrinkage of the fabric at the time of contraction of the sheet base after applying the polymer elastic body Can be alleviated. Further, by reducing the single fiber fineness, the flatness of the diameter of the twisted yarn constituting the woven fabric is increased, and there is an effect of alleviating strain in the artificial leather. When the single fiber fineness is smaller than 0.01 dtex, there are many single fiber breaks due to needle punching, which is not preferable in terms of deterioration of physical properties of the product. When the single fiber fineness is larger than 3.5 dtex, the exposure of the fibers constituting the fabric to the product surface is conspicuous due to the difference in dyeability with the ultrafine fibers constituting the nonwoven fabric, and the product quality tends to be lowered.

As described above, the woven density, twisted yarn diameter, single fiber fineness and number of twists related to the shrinkage of the fabric, especially the weave density and single fiber fineness are adjusted, and the dry heat shrinkage of the fabric at a temperature of 120 ° C. is 1%. By suppressing the area shrinkage of the artificial leather base sheet to 1% or more and 14% or less in the dyeing process after applying the elastic polymer, which causes uneven napped fiber density unevenness of the artificial leather by setting the content to 10% or less. it can.

By applying an elastic polymer to a sheet substrate made of a nonwoven fabric and a woven fabric, the bundle of ultrafine fibers is restrained, so that the dispersibility of napped fibers is fixed. Therefore, suppressing the shrinkage of the artificial leather substrate sheet after application of the elastic polymer leads to reduction in napped fiber density unevenness.

  The woven fabric used in the present invention may be woven with an arbitrary woven structure such as a plain weave, twill weave and satin weave, but a plain woven fabric is preferably used in consideration of the thickness and production cost of the fabric.

  The thickness of the woven fabric is preferably 0.10 mm or more and 0.40 mm or less, more preferably 0.15 mm or more and 0.30 mm or less. If the thickness of the woven fabric is smaller than 0.10 mm, the shape stability of the artificial leather is poor, and if the thickness is larger than 0.40 mm, distortion in the artificial leather of the woven fabric is large, and the napped fiber density unevenness tends to be large, and the quality tends to decrease. Show.

  The woven density of the woven fabric used in the present invention is adjusted so as to be 50 / inch to 100 / inch in the artificial leather. When the weaving density of the fabric in the artificial leather is less than 50 / inch, the strain of the fabric is relieved, but the shape stability tends to be lacking. Moreover, when the woven density of the woven fabric in the artificial leather is larger than 100 / inch, the woven fabric is distorted and the texture tends to be hard. Further, by reducing the woven density in the design of the woven fabric, the warp and weft intersections of the woven fabric are reduced, and the shrinkage rate of the woven fabric can be suppressed.

  The ultrafine fiber used in the artificial leather of the present invention can express an ultrafine fiber having a single fiber fineness of 1.0 dtex or less in order to enhance the performance as an artificial leather, that is, flexibility, tactile sensation, appearance quality, strength properties and the like. A configuration is preferred.

  Polymers constituting the ultrafine fibers include fiber types such as polyesters such as polyethylene terephthalate, polybutylene terephthalate and polyester elastomer, polyamides such as nylon 6, nylon 66 and polyamide elastomer, polyurethanes, polyolefins and acrylonitriles. However, polyester and polyamide polymers are preferably used from the viewpoint of practical performance.

  The unemployed fabric used for the artificial leather of the present invention is a short fiber nonwoven fabric obtained by forming a laminated web using a card or a cross wrapper and then needle punching or water jet punching, and a spunbond method. Or a non-woven fabric obtained by a papermaking method can be employed. Among them, the short fiber nonwoven fabric is preferably used because a napped fiber length is uniform and good.

  The preferred thickness of the nonwoven fabric is preferably 0.6 mm or more and 3.9 mm or less, more preferably 1.0 mm or more and 3.0 mm or less. If the thickness of the nonwoven fabric is smaller than 0.6 mm, the soft texture of the artificial leather is impaired, and if the thickness is larger than 3.9 mm, the shape stability of the artificial leather due to the inserted fabric tends to be poor.

  Examples of the elastic polymer used in the artificial leather of the present invention include polyurethane, polyurea, polyurethane / polyurea elastomer, polyacrylic acid, acrylonitrile / butadiene elastomer, and styrene / butadiene elastomer. Polyurethane is preferably used.

  In addition, the elastic polymer may contain an elastomer resin such as polyester, polyamide, and polyolefin, an acrylic resin, and an ethylene-vinyl acetate resin. The elastic polymer may be either dissolved in an organic solvent or dispersed in water.

With respect to a suitable use ratio of the elastic polymer, the weight of the elastic polymer with respect to the weight of the sheet substrate is preferably 10% by weight or more and 200% by weight or less, more preferably 20% by weight or more and 180% by weight or less. If the weight of the elastic polymer is less than 10% by weight, the fibers fall off from the artificial leather, and if the weight of the elastic polymer is more than 200% by weight, the texture of the artificial leather tends to be hard.

  In addition, the elastic polymer used in the present invention may include pigments such as carbon black, dye antioxidants, antioxidants, light-proofing agents, antistatic agents, dispersants, softeners, coagulation modifiers, difficulty if necessary. Additives such as a flame retardant, an antibacterial agent and a deodorizer may be blended.

<Manufacturing method of artificial leather>
Next, a method for producing the artificial leather of the present invention will be described.

  In the present invention, as a means for obtaining a nonwoven fabric in which ultrafine fiber bundles are entangled, it is preferable to use ultrafine fiber generating fibers such as sea-island type composite fibers. Since it is practically difficult to produce a nonwoven fabric directly from ultrafine fibers, a nonwoven fabric is first produced from ultrafine fiber-generating fibers, and ultrafine fibers are generated from the ultrafine fiber-generating fibers in this nonwoven fabric. A nonwoven fabric in which the bundles are intertwined can be obtained.

  The ultra-fine fiber generation type fiber is a sea-island type in which two-component thermoplastic resins with different solvent solubility are used for the sea component and the island component, and the sea component is dissolved and removed using a solvent, etc. It is possible to employ a peelable composite fiber that splits fibers into ultrafine fibers by alternately arranging fibers or two-component thermoplastic resin radially or in a multilayer shape on the fiber cross section, and separating and separating each component.

  For sea-island type fibers, sea-island type composite fibers that use a sea-island type composite base to spun two components of the sea component and the island component, and mixed spinning that mixes and spins the two components of the sea component and the island component are spun. Although there are fibers, etc., the sea-island type composite fiber is particularly useful because it can obtain ultrafine fibers of uniform fineness, and can obtain a sufficiently long ultrafine fiber that contributes to the strength of the sheet (fiber entanglement). Preferably used.

  As the sea component of the sea-island fiber, polyethylene, polypropylene, polystyrene, copolymerized polyester obtained by copolymerizing sodium sulfoisophthalic acid, polyethylene glycol, or the like, and polylactic acid can be used.

  The sea component may be dissolved and removed at any stage after the elastic polymer is applied, after the elastic polymer is applied, or after the raising treatment.

  As a method for obtaining a nonwoven fabric, as described above, a method of entanglement of a fiber web with a needle punch or a water jet punch, a spunbond method, a melt blow method, a papermaking method, etc. can be adopted, and among them, the ultrafine fiber as described above In forming the bundle, a method of undergoing a treatment such as a needle punch or a water jet punch is preferable. In the present invention, as described above, a short fiber nonwoven fabric obtained by applying these, a long fiber nonwoven fabric obtained from a spunbond method or a melt blow method, a nonwoven fabric obtained by a papermaking method, or the like can be employed. Among them, the short fiber nonwoven fabric is preferably used because a napped fiber length is uniform and good.

  In addition, a needle punch, a water jet punch or the like is preferably used for the lamination and integration of the nonwoven fabric and the fabric.

  In the needle punching process, the number of barbs is preferably 1-9. By making the number one or more, efficient fiber entanglement becomes possible. On the other hand, fiber damage can be suppressed by setting the number to 9 or less. When the number of barbs is more than 9, fiber damage becomes large, and needle marks may remain on the sheet substrate, resulting in poor appearance of the product.

  The total depth of the barb is preferably 0.05 to 0.09 mm. By setting the total depth of the barb to 0.05 mm or more, a sufficient catch on the fiber bundle can be obtained, so that efficient fiber entanglement is possible. Considering the balance between the strength of the barb portion and the fiber entanglement, the total depth of the barb is preferably 0.06 mm or more and 0.08 mm or less.

  When laminating and integrating a woven fabric and an ultrafine fiber generating fiber nonwoven fabric, the weft yarn of the fabric is loosened due to the sheet width contraction by the needle punch at the time of lamination, and is brought into the inner layer portion of the nonwoven fabric by the needle barb, and the product surface The fabric fibers are easily exposed. On the other hand, since the warp is always in a tension state due to the process tension, it is difficult to bring the warp into the nonwoven fabric inner layer by the needle barb. From these facts, it is preferable that the barb direction of the needle is directed in a direction in which the weft is not easily caught. Specifically, when the angle parallel to the weft of the woven fabric is 0 ° and the angle parallel to the warp that is perpendicular to it is 90 °, the needle barb is preferably directed to | 0 ° to 35 ° | , More preferably | 0 ° to 20 ° |, still more preferably | 0 ° to 10 ° |.

  In addition, the needle barb used may change in shape due to wear by needle punching a woven fabric and a non-woven fabric, and may cause deterioration in physical properties of the sheet substrate due to fiber damage. In order to avoid this, it is preferable to apply a film having wear resistance to the needle. Specifically, it is possible to use a punching needle in which a portion from the needle tip to at least the farthest barb is covered with a wear-resistant coating.

  Specifically, the coating covering the tip of the needle is preferably a coating made of a material having excellent wear resistance and low friction characteristics such as hard chrome or DLC (diamond-like carbon), and is particularly common and relatively low. A costly hard chrome coating is preferably used. Further, the thickness of the film is preferably about 1 to 7 μm, and most preferably 2 to 5 μm in consideration of the size of the barb. The hardness of the coating is preferably 500 Hv or more and 4500 Hv or less, and most preferably 600 Hv to 2000 Hv.

Further, it is desirable that preliminary entanglement is given before the nonwoven fabric and the woven fabric are entangled and integrated in order to further prevent the generation of wrinkles when the nonwoven fabric and the woven fabric are separated and integrated with the needle punch. As described above, when a method of preliminarily entangling with a needle punch is employed, it is effective that the punch density is 20 lines / cm ² or more, and preferably 100 lines / cm ^2. Pre-entanglement is preferably given at the above punch density, and more preferably pre-entanglement is given at a punch density of 300 / cm ^{2 to} 1300 / cm ² . When the pre-entanglement is 20 punches / cm ² or less, the width of the non-woven fabric remains narrowed due to the needle punch at the time of entanglement with the fabric and the subsequent needle punch. This is because the fabric may be wrinkled and a smooth sheet substrate may not be obtained. In addition, when the pre-entanglement punch density is 1300 / cm ² or more, generally, the nonwoven fabric itself is excessively entangled, and there is room for sufficient movement to sufficiently form the entanglement with the fibers constituting the woven fabric. This is because it decreases, which is disadvantageous for realizing a non-integral integrated structure in which the nonwoven fabric and the fabric are firmly intertwined.

In the present invention, when the woven fabric and the nonwoven fabric are entangled and integrated, the punch density range is preferably 300 / cm ^{2 to} 6000 / cm ^2, and 1000 / cm ^{2 to} 3000 / cm ^2. It is a more preferable embodiment.

  For the entanglement of the nonwoven fabric and the woven fabric, the woven fabric is laminated on one side or both sides of the nonwoven fabric, or the woven fabric is sandwiched between a plurality of nonwoven fabric webs, and the fibers are entangled with each other by a needle punch to form a sheet substrate. .

  The thickness of the sheet substrate obtained by needle punching is preferably 1.0 mm or more and 4.0 mm or less, and more preferably 1.5 mm or more and 3.5 mm or less. If the thickness is less than 1.0 mm, the sheet base becomes too soft and difficult to process, and if the thickness is greater than 4.0 mm, the sheet base tends to harden and difficult to process.

  Moreover, when performing a water jet punch process, it is preferable to perform water in the state of a columnar flow. Specifically, water may be ejected from a nozzle having a diameter of 0.05 to 1.0 mm at a pressure of 1 to 60 MPa.

The apparent density of the ultrafine fiber generating fiber nonwoven fabric after the needle punching process or the water jet punching process is preferably 0.15 to 0.30 g / cm ³ . By setting the apparent density to 0.15 g / cm ³ or more, an artificial leather having sufficient form stability and dimensional stability can be obtained. On the other hand, when the apparent density is 0.30 g / cm ³ or less, a sufficient space for imparting the elastic polymer can be maintained.

  From the viewpoint of densification, the ultrafine fiber generating fiber nonwoven fabric obtained in this way is preferably shrunk by dry heat or wet heat or both, and further densified.

  As the solvent for dissolving the easily soluble polymer (sea component) from the ultrafine fiber generating fiber, if the sea component is a polyolefin such as polyethylene or polystyrene, an organic solvent such as toluene or trichloroethylene is used. In the case of a copolyester, an alkaline aqueous solution such as sodium hydroxide can be used. The ultrafine fiber generation processing (sea removal treatment) can be performed by immersing a non-woven fabric made of ultrafine fibers in a solvent and squeezing it.

  In the present invention, N, N′-dimethylformamide, dimethyl sulfoxide, or the like is preferably used as a solvent used when polyurethane is imparted as an elastic polymer, but water-dispersed polyurethane in which polyurethane is dispersed as an emulsion in water. It may be a liquid.

  The elastic polymer solution is substantially provided by applying the elastic polymer to the sheet substrate by immersing a sheet substrate (fiber entangled body) made of a nonwoven fabric and a woven fabric in an elastic polymer solution dissolved in a solvent, and then drying. To solidify and solidify. In the case of a solvent-based polyurethane solution, it can be solidified by immersing it in an insoluble solvent, and in the case of a water-dispersed polyurethane liquid having gelling properties, a dry coagulation method for drying after gelation, etc. Can be solidified. In drying, the sheet substrate (fiber entangled body) and the elastic polymer may be heated at a temperature that does not impair the performance.

The artificial leather of the present invention may be raised at least on one side. The napping treatment can be performed using sandpaper, a roll sander or the like. In particular, by using sandpaper, uniform and dense napping can be formed. Furthermore, in order to form uniform napping on the surface of the artificial leather base sheet , it is preferable to reduce the grinding load. In order to reduce the grinding load, for example, it is more preferable that the number of buffing stages is multistage buffing with three or more stages, and the number of sandpaper used in each stage is in the range of 150 to 600 of JIS regulations. It is.

  Dyeing is preferably carried out using a high-temperature and high-pressure dyeing machine in order to soften the texture of the artificial leather base sheet to be dyed using disperse dyes, cationic dyes and other reactive dyes. The dyeing temperature is preferably 80 ° C to 150 ° C, more preferably 110 ° C or higher. If necessary, a finishing treatment such as a softening agent such as silicone, an antistatic agent, a water repellent, a flame retardant, and a light proofing agent may be performed. The finishing treatment may be performed after dyeing or in the same bath as dyeing.

  In the present invention, it is important to suppress the shrinkage rate after the application of the binder to suppress the texture of the raised surface unique to artificial leather, the uneven density of the raised fiber contributing to the lighting effect, specifically the dyeing process. The shrinkage rate of the artificial leather base sheet (raw machine) dyed in step 1 is controlled to 1% to 14% and dyed. The shrinkage rate is preferably 5% or more and 8% or less.

  As a method for suppressing the shrinkage rate in the finishing step such as dyeing, there is a method for suppressing the area shrinkage rate of the artificial leather base sheet after the elastic polymer is applied. Specifically, it is possible to suppress shrinkage of the artificial leather base sheet in the dyeing process, such as a method of lowering the dyeing temperature, a method of heat setting the artificial leather base sheet with a calender roll before the dyeing process, In the case of dyeing with a dye, since the dyeing property is lowered and the texture becomes hard, it is important to design the fabric so that the dry heat shrinkage rate is 1% or more and 10% or less in the design of the fabric. This can be achieved by adjusting the hot water shrinkage rate according to the woven density, single yarn diameter, single fiber fineness, and number of twists of the woven fabric.

  In addition, a woven fabric having a shrinkage rate of 1% or more and 10% or less in the dyeing process may be applied by a method of improving the crystallinity of the fiber and suppressing the shrinkage by heat setting during the production of the woven fabric.

  The dry heat shrinkage is preferably 5% or more and 9% or less.

  The artificial leather of the present invention not only has high strength and excellent shape stability, but also has a quality with little napped fiber density unevenness, and thus can be suitably used for a wide range of applications from furniture, chairs and vehicle interior materials to clothing.

  EXAMPLES Next, although an Example is given and this invention is demonstrated in more detail, this invention is not limited by these Examples.

[Measuring method and processing method for evaluation]
(1) Woven density of woven fabric A cross section perpendicular to the thickness direction of the artificial leather is observed at a magnification of 50 times with a scanning electron microscope (VE-7800 manufactured by SEM Keyence), and exists per 2.54 cm length. The number of yarn cross sections was evaluated.

(2) the diameter fabric twisting of the fabric was observed by 100 times magnification scanning electron microscope (SEM Keyence VE-7800 type) to evaluate the diameter of the twisted yarn by the average values measured 10 points.

(3) The quotient of the difference in height and the diameter of the twisted yarns of adjacent twisted yarn sections (referred to as parameter A)
Regarding the difference in height where the cross sections of the twisted yarn overlap, the cross section of the artificial leather is observed with a scanning electron microscope (VE-7800 manufactured by SEM Keyence Co., Ltd.) at a magnification of 50x, and the warp cross section and the weft cross section can be clearly observed. As shown in FIG. 1A, 10 overlapping heights of adjacent twisted yarn cross-sections were measured and evaluated by an average value.

The parameter A was evaluated by the second digit of the decimal point by the quotient of the above-described height difference of the twisted yarn cross sections and the actually measured twisted yarn diameter. The smaller the value of the parameter A, the more the distortion of the fabric in the artificial leather is suppressed, and the napped fiber density unevenness is reduced.

(4) Shrinkage rate of artificial leather base sheet in dyeing process Compare the width and length of artificial leather base sheet before dyeing process with the width and length of artificial leather after dyeing process, and calculate area shrinkage rate did.

(5) Dry heat shrinkage of fabric The area shrinkage of the fabric was calculated from the rate of change in the length and width of the fabric after heating the fabric (10 cm × 10 cm) at 120 ° C. for 20 minutes with a dryer.

(6) Surface quality evaluation It is evaluated by sensory inspection of 10 subjects. Eight or more people judged to be excellent (double circle), 5 to 7 people judged good (single circle), 3 to 4 people judged good (triangle), 2 or less people Were judged to be excellent, and each was classified as (X). Double circle and single circle were accepted.

[Example 1]
<Raw cotton>
Polyethylene terephthalate is used as an island component, polystyrene is used as a sea component, and a sea-island type composite base having 16 islands is used, and melt spinning is performed at an island / sea weight ratio of 80/20 at a spinning temperature of 285 ° C. It was drawn and crimped at a draw ratio of 3.0, and then cut into a length of 51 mm to obtain a raw material of sea-island type composite fiber having a single fiber fineness of 4.2 dtex.

<Entanglement of nonwoven fabric and woven fabric (sheet substrate)>
Using the above-mentioned sea-island type composite fiber, a laminated web is formed through a card and cross wrapping process, and needles are punched at a rate of 100 / cm ^{2 in} order to suppress fabric wrinkles due to sudden width changes after the fabrics are bonded. I punched. Thereafter, at 140μm diameter twisted yarn is in history both (110 dtex-288 filaments), number of twists 2000T / m, in weaving density is 80 × per inch 66 (vertical × horizontal), with dry heat shrinkage ratio of 8.8% A plain weave fabric was inserted above and below the laminated web. Thereafter, needle punching was performed at a punch number of 3000 / cm ² to obtain a sheet substrate.

<Artificial leather>
The sheet substrate is shrunk with hot water at a temperature of 96 ° C., impregnated with a 5% PVA (polyvinyl alcohol) aqueous solution, and dried with hot air at a temperature of 110 ° C. for 10 minutes. 4% by weight of a sheet substrate was obtained. This sheet substrate was immersed in trichlorethylene to dissolve and remove sea components, and a sea removal sheet in which ultrafine fibers and fabric were entangled was obtained. The seawater-free sheet comprising the nonwoven fabric and the woven fabric made of ultrafine fibers thus obtained is immersed in a DMF (dimethylformamide) solution of polyurethane adjusted to a solid content concentration of 12%, and then in an aqueous solution having a DMF concentration of 30%. To solidify the polyurethane. Thereafter, PVA and DMF are removed with hot water and dried with hot air at a temperature of 110 ° C. for 10 minutes, whereby an artificial leather base having a polyurethane weight of 27% by weight with respect to the total weight of the ultrafine fibers made of island components and the fabric is obtained. A material sheet was obtained.

The artificial leather base sheet thus obtained was cut in half in the direction perpendicular to the thickness direction, and the half-cut surface was ground with an endless sandpaper having sandpaper count 240 to form a raised surface. The thus obtained artificial leather base sheet before the dyeing process is subjected to shrinkage treatment and dyeing simultaneously under a temperature condition of 120 ° C. using a liquid dyeing machine, and then dried with a dryer. Got artificial leather. The artificial leather thus obtained was measured for parameter A for evaluating the strain of the fabric. As a result, the warp was 0.22 and the weft was 0.09, both of which were 0.25 or less, as shown in FIG. Thus, there was little unevenness of napped fiber density, and it had a quality with a flat feeling. The results are shown in Table 1.

[Example 2]
<Raw cotton>
In the same manner as in Example 1, a sea-island composite fiber raw cotton having a single fiber fineness of 4.2 dtex and a fiber length of 51 mm was obtained.

<Entanglement of nonwoven fabric and woven fabric (sheet substrate)>
The inserted fabric between nonwoven, with 160μm diameter twisted yarn is in history both (144dtex-408 filaments), number of twists 1200T / m, in weaving density per inch 74 × 63 (vertical × horizontal), dry heat shrinkage A sheet substrate was obtained in the same manner as in Example 1 except that the woven fabric was changed to a woven fabric having a plain weave structure of 7.8%.

<Artificial leather>
Artificial leather was obtained in the same manner as Example 1. As a result of measuring the parameter A for evaluating the distortion of the fabric, the artificial leather has a warp of 0.11 and a weft of 0.08, both of which are 0.25 or less, and there is little unevenness in napped fiber density and a flat feeling. Had quality. The results are shown in Table 1.

[Example 3]
<Raw cotton>
In the same manner as in Example 1, a sea-island composite fiber raw cotton having a single fiber fineness of 4.2 dtex and a fiber length of 51 mm was obtained.

<Entanglement of nonwoven fabric and woven fabric (sheet substrate)>
The inserted fabric between nonwoven diameter of twisting at 150μm (124dtex-3000 filaments) in the background both twist number 2000T / m, in weaving density per inch 82 × 66 (vertical × horizontal), dry heat shrinkage A sheet substrate was obtained in the same manner as in Example 1 except that the woven fabric was changed to a woven fabric having a plain weave structure of 7.0%.

<Artificial leather>
Artificial leather was obtained in the same manner as Example 1. As a result of measuring the parameter A for evaluating the strain of the fabric, the artificial leather has a warp of 0.12 and a weft of 0.11, both of which are 0.25 or less, and there is little unevenness of napped fiber density and a flat feeling. Had quality. The results are shown in Table 1.

[Example 4]
<Raw cotton>
In the same manner as in Example 1, a sea-island composite fiber raw cotton having a single fiber fineness of 4.2 dtex and a fiber length of 51 mm was obtained.

<Entanglement of nonwoven fabric and woven fabric (sheet substrate)>
The inserted fabric between the nonwoven, the diameter of the twisted yarns are circumstances both at 130 .mu.m (110 dtex-288 filaments), number of twists 3700T / m, in weaving density per inch 80 × 70 (vertical × horizontal), dry heat shrinkage A sheet substrate was obtained in the same manner as in Example 1 except that the woven fabric was changed to a woven fabric having a plain weave structure of 6.5%.

<Artificial leather>
Artificial leather was obtained in the same manner as Example 1. As a result of measuring the parameter A for evaluating the strain of the woven fabric, the artificial leather has a warp of 0.18 and a weft of 0.09, both of which are 0.25 or less, and there is little unevenness in napped fiber density and a flat feeling. Had quality. The results are shown in Table 1.

[Example 5]
<Raw cotton>
By using polyethylene terephthalate as the island component, copolymerized polyethylene terephthalate copolymerized with 8 mol% of 5-sodium isophthalic acid as the sea component, and using a sea-island type composite base with 16 islands, After melt spinning at a weight ratio of 60/40 at a spinning temperature of 285 ° C., the island is stretched at a draw ratio of 3.0 times and crimped, then cut to a length of 51 mm, and a sea island type with a single fiber fineness of 5.0 dtex A raw fiber of composite fiber was obtained.

<Entanglement of nonwoven fabric and woven fabric (sheet substrate)>
Except for using the above raw cotton, in the same manner as in Example 1, at 140μm in diameter of twine are circumstances co (110 dtex-288 filaments), twist number 2000T / m, 80 weave density per inch × 66 (vertical A sheet substrate was obtained using a woven fabric of (××).

<Artificial leather leather>
Sodium sulfate as a heat-sensitive gelling agent is added to the nonionic forced emulsification type polyurethane emulsion (polycarbonate), which is a water-dispersed polyurethane liquid, in an amount of 4% by mass relative to the polyurethane solid content, so that the polyurethane liquid concentration becomes 10% by mass. A water-dispersed polyurethane liquid was prepared. The sheet base obtained as described above is provided with the water-dispersed polyurethane liquid, dried with hot air at a drying temperature of 120 ° C. for 5 minutes, and the polyurethane weight relative to the total weight of the ultrafine fibers made of island components and the woven fabric. Of 30% by weight of artificial leather base sheet was obtained.

The polyurethane-coated sheet obtained as described above was immersed in a 40 g / L sodium hydroxide aqueous solution heated to a temperature of 90 ° C. and treated for 30 minutes to dissolve and remove sea components from the sea-island composite fibers. Then, half-cut perpendicularly to the thickness direction using a half-cutting machine with an endless band knife, and the non-half-cut surface is ground in three steps using JIS # 320 sandpaper to form napped hair to form an artificial leather base sheet Was made. The artificial leather base sheet before the dyeing process thus obtained was subjected to shrinkage treatment and dyeing at the same time under a temperature of 120 ° C. with a liquid dyeing machine, and then dried with a drier to produce artificial artificial leather. Got leather. As a result of measuring the parameter A for evaluating the strain of the woven fabric for this artificial leather, the warp was 0.13 and the weft was 0.12, both in the same manner as in Example 1, both of which were 0.25 or less, and the napped fiber density unevenness There were few, and it had the quality with a flat feeling.

[Comparative Example 1]
<Raw cotton>
In the same manner as in Example 1, a sea-island composite fiber raw cotton having a single fiber fineness of 4.2 dtex and a fiber length of 51 mm was obtained.

<Entanglement of nonwoven fabric and woven fabric (sheet substrate)>
The inserted fabric, diameter of twisted warp and weft yarns 120 [mu] m (84 dtex-72 filaments), number of twists 2500T / m, except that the weaving density was changed to fabric 96 × 76 per inch (via × weft) In the same manner as in Example 1, a sheet substrate was obtained. The dry heat shrinkage of the fabric was 10.6%.

<Artificial leather leather>
Using the above sheet base, artificial leather was obtained in the same manner as in Example 1. With respect to this artificial leather, the parameter A for evaluating the strain of the fabric was measured. As a result, the warp was 0.77 and the weft was 0.30, both of which were 0.25 or more. The surface quality was noticeable and uneven. The results are shown in Table 1.

[Comparative Example 2]
<Raw cotton>
In the same manner as in Example 1, a sea-island composite fiber raw cotton having a single fiber fineness of 4.2 dtex and a fiber length of 51 mm was obtained.

<Entanglement of nonwoven fabric and woven fabric (sheet substrate)>
Inserted fabrics, twisted diameter is warp 120 [mu] m, the weft 140 .mu.m (warp 110 dtex-24 filaments, the weft 110 dtex-288 filaments), the warp twist number is 1800T / m, the weft 2000T / m, weave density per inch 77 A sheet substrate was obtained in the same manner as in Example 1 except that the fabric was changed to a fabric of × 66 (warp × weft). The dry heat shrinkage of the fabric was 12.3%.

<Artificial leather>
To obtain an artificial leather leather in the same manner as in Example 1. As a result of measuring the parameter A for evaluating the distortion of the fabric of this artificial leather, the wefts were 0.35 and 0.25 or more, the napped fiber density unevenness was conspicuous, and the surface quality was uneven. The results are shown in Table 1.

A. Overlapping height difference between adjacent thread sections

Claims (4)

In an artificial leather in which an elastic polymer is added as a binder to a sheet substrate in which a nonwoven fabric made of ultrafine fibers and a woven fabric are entangled and integrated, a difference in height between adjacent twisted yarn cross sections of the woven fabric and a twisted yarn diameter of the woven fabric Artificial leather characterized by having a quotient of 0.25 or less.   The artificial leather according to claim 1, wherein the woven density of the woven fabric is 50 / inch or more and 100 / inch or less. Producing claim 1 or 2 wherein the artificial leather artificial leather base sheet elastic polymer sheet substrate non-woven fabric and woven fabric made of ultrafine fibers formed by integrally entangled is granted as a binder stained and in the method, as the fabric area shrinkage with 10% or less of the fabric than 1% at a temperature of 120 ° C., controlled shrinkage at the artificial leather base sheet of the dyeing process to be 1 or more than 14% method of manufacturing to that artificial leather, characterized in that. Producing claim 1 or 2 wherein the artificial leather artificial leather base sheet elastic polymer sheet substrate non-woven fabric and woven fabric made of ultrafine fibers formed by integrally entangled is granted as a binder stained and in the method, a manufacturing method of that artificial leather to, characterized in that through the at least the following I~III process.
I. A short fiber web made of ultrafine fiber-generating fibers and a woven fabric having an area shrinkage of 1% to 10% at a temperature of 120 ° C. are laminated, and the nonwoven fabric and the woven fabric are intertwined and integrated by a needle punching process. Obtaining a sheet substrate.
II. After removing the elution component of the ultrafine fiber generating fiber of the sheet base obtained in the step I, the polymer elastic body is applied, or after the polymer elastic body is applied, the elution component of the ultrafine fiber generating fiber is added. The process of obtaining the artificial leather base sheet before the dyeing process ground and raised by sandpaper after removing.
III. A step of obtaining artificial leather by performing fluid flow dyeing on the artificial leather base sheet obtained in Step II and controlling the shrinkage before and after dyeing to be 1 % or more and 14% or less.