JP4884661B2 - Artificial leather and method for producing the same - Google Patents

Description

  The present invention relates to an artificial leather excellent in stretchability. More specifically, the present invention does not substantially cause structural deformation even when repeatedly stretched and deformed, that is, it has excellent stretchability, form retention, form stability and form recovery, and has a flexible and fulfilling texture. Has artificial leather. Furthermore, when raising at least one side is formed, it is related to a raised artificial leather that is excellent in uniformity of the raised state and excellent in texture, stretchability and drape, or at least one of When a coating layer is formed on the surface, it is not only excellent in texture, stretchability, and drape, but also related to artificial leather with silver that has excellent surface smoothness and peel strength even with an extremely thin coating layer It is. Moreover, this invention relates to the manufacturing method of the said artificial leather.

  A napped sheet in which napped fibers are formed on at least one surface of a fiber fabric such as a woven or knitted fabric or a non-woven fabric, or a fibrous base material having a foamed structure of an elastic polymer is expressed by the length of napped fibers or the fineness of texture. In recent years, it has been produced in large quantities as a nap-like or nubuck raised sheet because its appearance, texture and feel are similar to those of natural leather suede or nubuck. In particular, a known suede tone or nubuck tone in which napped fibers made of ultrafine fiber bundles are present on the surface of a fiber substrate made of a fiber entangled nonwoven fabric made of ultrafine fiber bundles and an elastic polymer contained therein. Napped-toned artificial leather is superior, including the elegantness of the raised surface, soft touch, full texture, light draping, and the fraying of the yarn found on the woven fabric substrate at the sheet cutting edge. It is a material that not only has characteristics and is similar to natural leather in terms of structure, but also has performance equivalent to or higher than that of natural leather in terms of quality.

In the field of napped-toned artificial leather, further improvement in quality is required. Appearance such as suede or nubuck, soft hand, aesthetics such as excellent texture and draping, touch, and comfort. There is a need to provide high-quality products that satisfy all the characteristics related to.
For example, a nonwoven fabric obtained by entanglement of a fiber made of an elastic polymer (elastic fiber) and a fiber made of a non-elastic polymer (non-elastic fiber) in order to obtain a napped artificial leather having elasticity and excellent texture An entangled nonwoven fabric excellent in elasticity, which is contracted in an area ratio of 10 to 80%, is known. (For example, see Patent Document 1). However, the artificial leather obtained from the proposed elastic fiber and non-elastic fiber is excellent in drape because the elastic fiber is all in the fiber state and is flexible. Since the binder effect to be retained was small, the passing through the raising process by buffing or the like was poor, the fluffiness was rough, and the appearance of the suede or nubuck was far from it.
In addition, artificial leather using a composite fiber that generates two or more types of elastic fibers having different melting points and an ultrafine non-elastic fiber generating fiber has been proposed (for example, patent literature). 2). However, the low-melting point elastic fiber constituting the artificial leather melts only to give a low binder effect, and the binder effect is insufficient. And these methods could not produce artificial leather with a suede-like appearance.

In addition, impregnating polyurethane into a nonwoven fabric consisting only of sea-island fibers that generate inelastic ultrafine fibers, removing the sea components by solvent extraction, etc. to generate inelastic ultrafine fibers, and then dyeing treatment results in excellent appearance It has been proposed that an artificial leather can be obtained (see, for example, Patent Document 2). However, since elastic fibers are not contained in the nonwoven fabric, structural changes occur when repeated elongation and deformation are performed. Moreover, since the impregnated polyurethane resin is present in the form of a foamed sheet inside the nonwoven fabric, an artificial leather excellent in soft hand, texture and drapeability could not be obtained.
In the methods described in Patent Document 1 and Patent Document 2 described above, although the artificial leather is given stretchability, a fiber raised surface having an excellent appearance cannot be obtained. Moreover, according to the method described in Patent Document 3, an excellent appearance can be obtained, but it has been difficult to obtain excellent stretchability, texture and drape.

Japanese Patent Publication No. 01-41742 Japanese Examined Patent Publication No. 03-16427 Japanese Patent Publication No. 05-65627

  An object of the present invention is an artificial leather comprising a fiber-entangled nonwoven fabric in which fibers made of an elastic polymer and ultrafine fibers made of an inelastic polymer are mixed, and has excellent stretchability, texture, and drapeability, and a method for producing the same, and further appearance It is to provide a napped-tone artificial leather and an artificial leather with silver.

In order to achieve the above object, the present inventors have intensively studied and found the method described below to arrive at the present invention. That is, the present invention relates to an artificial leather composed of an ultrafine fiber composed of an inelastic polymer having an average fiber diameter of 5 μm or less and an elastic polymer, and the elastic polymer is mainly composed of the inelastic fiber in the thickness direction of the artificial leather. An entangled nonwoven fabric structure is formed with ultrafine fibers made of a polymer, and a part of the elastic polymer is integrated with the entangled nonwoven fabric structure on at least one surface of the artificial leather and is continuous in the surface direction. It is an artificial leather characterized by forming a quality layer. And it is preferable that the elastic polymer of a fiber form is a partly porous state, and it is preferable to have the structure where the fine fiber which consists of non-elastic polymers, and the fiber which consists of elastic polymers partially adhered. Further, the artificial leather is a napped-tone artificial leather in which at least a porous layer of the artificial leather is formed with napped fibers mainly composed of ultrafine fibers made of an inelastic polymer, and at least the porous layer of the artificial leather This is a silver-tone artificial leather having a coating layer on the surface on which is formed.

Moreover, this invention is a manufacturing method of the artificial leather characterized by performing the process of following I-III sequentially.
I. At least a part of the fiber made of an elastic polymer is present on the surface, the fiber (A) capable of generating a fiber made of the elastic polymer and the fiber capable of generating an ultrafine fiber made of an inelastic polymer having an average fiber diameter of 5 μm or less A step of producing an entangled nonwoven fabric comprising (B),
II. A liquid containing at least a good solvent for the elastic polymer is applied to at least one surface of the entangled nonwoven fabric, and at least the elastic polymer in the fiber (A) present in the surface layer portion is partially dissolved, and then the Applying a liquid containing at least a poor solvent for the elastic polymer, and III. A step of generating fibers made of an elastic polymer and ultrafine fibers made of an inelastic polymer having an average fiber diameter of 5 μm or less from the fibers (A) and (B), respectively.

  The artificial leather of the present invention is an artificial leather that does not substantially undergo structural deformation even when repeatedly stretched and deformed, that is, has excellent stretchability and fiber entanglement, and has a soft and solid texture. When the napped surface is formed on at least one surface, the napped surface artificial leather is excellent in the appearance of the napped surface and excellent in texture, stretchability and drape. In addition, this artificial leather is excellent in texture, stretchability and drape when a coating layer mainly composed of an elastic polymer is formed on at least one surface. It is also useful as an artificial leather that is the base of artificial leather with silver that has excellent surface smoothness and excellent peeling strength of the coating layer, and is applicable to a wide range of applications such as clothing, furniture, shoes, and bags. it can.

The present invention is described in detail below.
Fiber made of elastic polymer (elastic fiber) is melt-spun by elastic polymer alone or melted by combining elastic polymer and at least one kind of spinnable polymer having different chemical or physical properties. It is obtained by dividing the spun multicomponent fiber or by extracting and removing at least one polymer from the multicomponent fiber. The multi-component fiber is a fiber (hereinafter simply referred to as fiber (A)) in which an elastic fiber-forming component is present on at least a part of its surface, and elastic fiber can be generated by division, extraction operation, or the like. . The fiber (A) is not particularly limited as long as it is a composite fiber having a structure in which an elastic polymer is present on a part of its surface, but sea island type fibers, split type fibers and the like are preferable. Among these, sea-island type fibers are more preferable, and sea-island type mixed spun fibers are more preferable because elastic polymers are likely to be randomly present as island components on a part of the surface of the fiber. On the surface of the fiber (A), the area ratio occupied by the elastic polymer is preferably 0.1 to 95%, and more preferably 1 to 70%. If it is 0.1% or more, the elastic fibers are easily made partially porous, and a partially fused state between the elastic fibers is easily obtained. Moreover, the fall of process passability, such as card passability resulting from the property of an elastic polymer, can be prevented as it is 95% or less.

Examples of the elastic polymer include at least one selected from polymer polyols having a number average molecular weight of 500 to 3500 such as polyester polyol, polyether polyol, polyester ether polyol, polylactone polyol, and polycarbonate polyol, and 4,4′-. Aromatic, alicyclic, and aliphatic organic polyisocyanates such as diphenylmethane diisocyanate, tolylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, hexamethylene diisocyanate, and 1,4-butanediol; Polyurethanes obtained by reacting with chain extenders having two active hydrogen atoms such as ethylenediamine; polyesters such as polyester elastomers and polyetherester elastomers Steal elastomers; Polyamide elastomers such as polyetheresteramide elastomer and polyesteramide elastomer; Conjugated diene polymers such as polyisoprene and polybutadiene; Block copolymers having conjugated diene polymer blocks such as polyisoprene and polybutadiene in the molecule Polymers; and elastomers having rubber elastic behavior that can be melt-spun. Among them, polyurethanes are most preferable in view of high flexibility, low resilience and high friction resistance, high adhesion to non-elastic ultrafine fibers, and excellent heat resistance and durability.
It should be noted that an additive such as a pigment such as carbon black or a thermal stability improver of the resin can be added to the elastic polymer within a range not impairing the effects of the present invention.

  The sea component polymer (the polymer to be extracted or decomposed and removed) of the fiber (A), which is a multicomponent fiber, needs to be different from the island component polymer in solubility in a solvent or decomposability in a decomposing agent. For example, the solubility or decomposability is larger than the island component polymer, the compatibility or affinity with the island component polymer is small, and the melt viscosity is smaller than the melt viscosity of the island component polymer, or the surface tension of the island component polymer is A polymer having a surface tension smaller than that is preferably used as the sea component polymer. Examples of such polymers include easily soluble polymers such as polyethylene, polystyrene, modified polystyrene, and ethylene propylene copolymer, and easily modified (copolymerized) polyethylene terephthalate modified with sodium sulfoisophthalate and polyethylene glycol. Examples thereof include melt-spinnable polymers such as degradable polymers.

  Does an ultrafine fiber made of an inelastic polymer (inelastic ultrafine fiber) divide a multicomponent fiber made of an inelastic polymer and at least one spinnable polymer having different chemical or physical properties from the inelastic polymer? Alternatively, it can be obtained by extracting and removing at least one kind of polymer from the multicomponent fiber. The multicomponent fiber is a fiber capable of generating an inelastic ultrafine fiber having an average fiber diameter of 5 μm or less by division, extraction operation, or the like (hereinafter sometimes simply referred to as fiber (B)). The average fiber diameter of the ultrafine fibers generated from the fiber (B) of the present invention needs to be 5 μm or less, preferably 3 μm or less, more preferably 1.5 μm or less. When the average fiber diameter exceeds 5 μm, the texture with softness and fullness is inferior, and when it is made of artificial leather, the overall appearance is very rough, and the texture is smooth and natural leather. It becomes inferior to a high-class feeling such as touch. The lower limit of the average fiber diameter of the fiber (B) is not particularly limited, but is preferably 0.01 μm or more from the viewpoint of color developability and physical properties.

Examples of non-elastic polymers include melt-spinnable polyamides such as nylon-6, nylon-66, nylon-10, nylon-11, nylon-12, and copolymers thereof; polyethylene terephthalate, polytrimethylene terephthalate, Examples thereof include melt-spinnable polyesters such as polybutylene terephthalate and cationic dyeable modified polyethylene terephthalate; and melt-spinnable polyolefins such as polypropylene and copolymers thereof. You may use the said polymer individually or in mixture of 2 or more types of polymer.
When the fiber (B) is a sea-island type fiber, the inelastic polymer constituting the island component needs to be separated into microfibers without unnecessarily fusing the generated inelastic ultrafine fibers. Therefore, when both the fiber (A) and the fiber (B) are sea-island fibers, an inelastic polymer is selected so that at least the inelastic ultrafine fibers are not fused together by solvent treatment for extracting and removing sea components. It is preferable to do. Specifically, a polymer having a solvent swelling rate of 10% by mass or less in the sea component removal treatment is preferable.
In addition, an additive such as a pigment typified by carbon black or the like or a thermal stability improver of a resin can be added to the inelastic polymer as long as the effects of the present invention are not impaired.

The fiber (B) is not particularly limited as long as it is a composite fiber capable of generating an inelastic ultrafine fiber having an average fiber diameter of 5 μm or less, but sea island type fibers, split type fibers and the like are preferable. The content of the inelastic polymer in the fiber (B) is preferably 10 to 90% by mass, and more preferably 30 to 70% by mass.
The sea component polymer of the fiber (B) is basically the same as that of the fiber (A), and the polymers described for the fiber (A) can be used. The sea component of the fiber (B) and the fiber (A) may be different polymers. However, in order to efficiently remove the sea component, the same kind of polymer is preferable.
From the viewpoint of melt spinning stability, it is preferable to select a polymer having a melting point suitable for the melt spinning temperature of the elastic polymer as the non-elastic polymer, the polymer constituting the sea component of the fiber (A) and the fiber (B). . For example, when polyurethane is used as the elastic polymer, the melting point of the non-elastic polymer and the polymer constituting the sea component is about 230 ° C. or less, and when using a polyester elastomer or polyamide elastomer as the elastic polymer, it is non-elastic. The melting point of the polymer and the polymer constituting the sea component is preferably selected to be about 260 ° C. or lower.

  The fiber (A) and the fiber (B) can be obtained by a known spinning method, and are made into a nonwoven fabric by a known method. For example, after drawing the fiber (A) and the fiber (B), crimping, cutting and applying an oil agent are applied, and after blending (mixing) at a desired ratio, the card is defibrated and a web is formed through the webber. . In this case, the ratio of blending (mixing) of the fibers (A) and the fibers (B) is such that the elastic polymer: inelastic polymer is 20:80 to 80:20 by mass ratio. It is preferable in terms of excellent properties and texture, and is preferable in that the napped state of the napped artificial leather is good. When the ratio of the elastic polymer is 20% by mass or more, the stretchability of the obtained artificial leather becomes good, and when it is 80% by mass or less, it is possible to avoid the effect of raising the hair from being hardly expressed, It is possible to prevent an insufficient napped state from being rubber-like.

Next, the obtained web is laminated to a desired weight and thickness, and then entangled with a known method such as needle punching or high-speed water flow to obtain an entangled nonwoven fabric. The entangled nonwoven fabric is preferably heat-treated at a temperature in the range of 50 to 150 ° C. or heat-treated with hot water in the range of 50 to 95 ° C. to obtain excellent stretchability. The shrinkage rate is determined by the fiber type, the mass ratio of the elastic polymer and the non-elastic polymer, the spinning conditions and the stretching conditions of the fibers (A) and (B). The area shrinkage ratio of the entangled nonwoven fabric is 5 to 50% in that the appearance and stretchability of the resulting artificial leather are improved, and further, the structure of the artificial leather is not substantially changed even after repeated elongation and deformation. It is preferable to be in the range.
Further, if necessary, the entangled nonwoven fabric may be temporarily fixed with a resin that can be dissolved and removed, such as a water-soluble paste such as a polyvinyl alcohol resin. Moreover, you may heat-press the surface of this entangled nonwoven fabric by a well-known method from the point which improves the smoothness of a surface and provides the lighting effect which was further excellent in the napped-tone artificial leather.
The thickness of the obtained entangled nonwoven fabric can be arbitrarily selected depending on the use of artificial leather and the like, and is not particularly limited. However, in the case of one layer, the thickness is preferably about 0.2 to 10 mm. More preferably, it is about 4-5 mm. Density is preferably ^{0.20~0.65g / cm 3, 0.25~0.55g / cm} 3 is more preferable. When it is 0.20 g / cm ³ or more, it is possible to avoid a feeling of napping of the fibers and further decrease in mechanical properties. It can avoid that the texture of the artificial leather obtained as 0.65 g / cm ³ or less becomes hard.

A known elasticity comprising a solution that does not dissolve the elastic polymer constituting the fiber (A) within the obtained entangled nonwoven fabric so as not to impair the effect of the present invention in order to enhance the shape retention of the obtained entangled nonwoven fabric. A polymer may be added. In that case, the mass ratio of the elastic polymer to the fibers constituting the entangled nonwoven fabric is preferably 0.1 to 10%, more preferably 0.5 to 5%. When the elastic polymer is polyurethane, it is preferably applied as a polyurethane emulsion.
Next, a liquid containing at least a good solvent for the elastic polymer is applied to at least one surface of the entangled nonwoven fabric, and at least the elastic polymer in the fiber (A) present in the surface layer portion is partially dissolved, It is necessary to apply a liquid containing at least a poor solvent for the elastic polymer.
That is, a treatment liquid A containing at least a good solvent for the elastic polymer constituting the fiber (A) is applied to at least one surface of the entangled nonwoven fabric, and a part of the elastic polymer is applied to the surface or end surface of the fiber (A). The elastic polymer in the fiber (A) partially present on the surface is partially dissolved by utilizing the exposed surface of the fiber, and then a treatment liquid B containing a poor solvent for the elastic polymer is applied. It is important to form a porous layer by solidifying the dissolved elastic polymer into a porous state. Furthermore, it is preferable to fuse the elastic polymers partially.

Examples of the solvent for the elastic polymer include, when the elastic polymer is polyurethane, good solvents for polyurethane such as N, N-dimethylformamide (DMF), dioxane, alcohols, etc., among which DMF is preferable. The treatment liquid A may be a combination of a good solvent and a poor solvent for the elastic polymer, and may further be an elastic polymer solution containing an elastic polymer in the treatment liquid A. The elastic polymer solution is preferably an elastic polymer solution similar to the elastic polymer constituting the fiber. For example, when the elastic polymer constituting the fiber is polyurethane, the elastic polymer solution is also a polyurethane solution. It is preferable at the point which forms a layer easily.
The concentration of the elastic polymer is preferably 1 to 30% by mass and more preferably 1 to 10% by mass in terms of solid content. When it is 30% by mass or less, although depending on the amount of impregnation, the elastic polymer solution is applied and submerged in the entangled nonwoven fabric, so that the elastic fiber and / or the non-elastic microfiber are fixed by the excess elastic polymer. Therefore, it is possible to prevent the degree of freedom from being lost and to prevent the drapeability and stretchability of the resulting artificial leather from being lowered.

  In addition, the elastic polymer (a) present due to the application of the elastic polymer solution in the obtained artificial leather, the fibrous form present due to the fiber (A) used during the production of the entangled nonwoven fabric, and a part The mass ratio with the elastic polymer (b) taking the porous form is preferably (a) / (b) = 0/100 to 30/100, more preferably 0.5 / 100 to 10/100. is there. By setting the ratio of the elastic polymer (a) to 30 or less, the elastic fiber and / or the non-elastic ultrafine fiber is fixed by the elastic polymer and loses the degree of freedom, and the drapeability and stretchability of the resulting artificial leather are reduced. Can be prevented.

Further, when the treatment liquid A contains an elastic polymer, the thickness of the porous layer formed on the surface layer portion by application of the treatment liquid A is desirably 60% or less of the total thickness constituting the artificial leather. More preferably, it is 40% or less. In addition, the thickness of the porous layer said here is the thickness which added the thickness of each porous layer of both surfaces, when the porous layer is formed in both surfaces. By making the thickness of the porous layer 60% or less of the total layer thickness, it is possible to prevent the texture, drapability and stretchability of the resulting artificial leather from being lowered.
When the treatment liquid A contains an elastic polymer, for example, at least one polymer diol having an average molecular weight of 500 to 3000 selected from polyester diol, polyether diol, polyether ester diol, polylactone polyol, polycarbonate diol, and the like , 4,4′-diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate and other aromatic, alicyclic, and aliphatic organic polyisocyanates, ethylene glycol, ethylenediamine, and the like Polyurethane obtained by reacting at least one low molecular weight compound having two or more active hydrogen atoms in a predetermined molar ratio is preferably used as the elastic polymer. Moreover, you may add polymers, such as a synthetic rubber and a polyester elastomer, to a polyurethane as needed. In the treatment liquid A containing an elastic polymer, additives such as a colorant, a coagulation regulator, and an antioxidant may be blended as necessary.

Next, it is important to apply to the entangled nonwoven fabric coated with the treatment liquid A a liquid containing at least a poor solvent for the elastic polymer (hereinafter also referred to as the treatment liquid B). And as a poor solvent of an elastic polymer, the non-solvent with respect to the polyurethane represented by water etc. is mentioned when an elastic polymer is a polyurethane. After the treatment liquid A is applied to at least one surface of the entangled nonwoven fabric, the treatment liquid B is impregnated to solidify the partially dissolved elastic polymer in a porous state. When solidifying, it is preferable to form a porous layer in which melted elastic polymers existing in different places are partially fused to each other and the fibers (A) are partially fused.
The ratio of the elastic solvent forming component existing on the surface of the fiber (A) is increased by a known spinning method, the amount of the treatment liquid A impregnated is increased, and the ratio of the good solvent to the elastic polymer in the treatment liquid A is further increased. It is preferable to form the porous layer in a state in which a network structure is partially generated by adjusting the number of the fusion points of the fibers (A). Furthermore, it is preferable to form a porous layer in which the elastic polymer solution and the elastic polymer constituting the fiber are mixed after coagulation. By forming the porous layer, the resulting artificial leather is stretchable and does not substantially undergo structural deformation even when repeatedly stretched and deformed, and is excellent in texture and drape.
Here, the porous state means a fine sponge state formed when the elastic polymer is wet-solidified. When the elastic fiber generated from the fiber (A) is partially porous, the texture and drape of the resulting artificial leather are excellent.

  Examples of a method for applying the treatment liquid A containing at least a good solvent for the elastic polymer constituting the fiber (A) on at least one surface of the entangled nonwoven fabric include a knife coating method, a blade coating method, a lip coating method, and a rod coating. Various known coating methods such as a method, a reverse roll coating method, a gravure roll coating method, a kiss coating method, and a spray coating method may be used. Among these, the blade coating method and the lip coating method can be applied only to the surface layer portion of the entangled nonwoven fabric, and moreover, a low-concentration and low-viscosity liquid can be easily and uniformly applied to the surface of the fiber (A). A gravure roll coating method, a spray coating method and the like are preferably used.

  In addition, when the elastic fiber forming component exposed on the surface or end face of the fiber (A) is partially dissolved by applying the treatment liquid A to at least one surface of the entangled nonwoven fabric, dissolution more than necessary is required. In order to avoid this, the treatment with the treatment liquid A is preferably performed at 10 to 60 ° C. for 30 seconds to 4 minutes. Immediately after the treatment or after removing the excess treatment liquid A, the treatment liquid B is applied. The treatment liquid B can be impregnated by the method described above. The treatment with the treatment liquid B is preferably performed at 25 to 50 ° C. for 10 to 30 minutes, and the application amount of the treatment liquid B is 100 parts by mass or more with respect to 100 parts by mass of the total elastic polymer contained in the entangled nonwoven fabric. It is preferable in terms of the solidification stability of the elastic fiber forming component.

The entangled nonwoven fabric is treated with the treatment liquid A and the treatment liquid B as described above and then dried, and then elastic fibers and inelastic ultrafine fibers are generated from the fibers (A) and fibers (B). When the fiber (A) and the fiber (B) are sea-island type fibers, it is preferably treated with a liquid that dissolves or decomposes sea components by a method such as immersion. For example, when the sea component is polyethylene or polystyrene, toluene is used, and when the sea component is an easily alkali-degradable polyester, an aqueous caustic soda solution is used. The amount of the dissolved or decomposed solution used is preferably 100 parts by mass or more with respect to 100 parts by mass of the total amount of the sea component polymer, the treatment temperature is preferably 5 to 50 ° C., and the treatment time is preferably 5 to 40 minutes. .
By this treatment, the sea component is removed from the fiber (A) and the fiber (B). The fibers (A) are converted into elastic fibers that are partially porous. The generated elastic fibers are partially fused together to form a network structure. The fibers (A) present in at least the surface layer part are aggregates of fibers made of an elastic polymer partially in a porous state, and the fibers made of the elastic polymer, or the elastic polymer and part of the treatment liquid A By partly fusing, a part of the elastic polymer forms a porous layer integrated with the entangled nonwoven structure in at least one surface layer portion of the artificial leather. Further, the fiber (B) is transformed into an inelastic ultrafine fiber or a fiber bundle thereof. The elastic fiber and the inelastic ultrafine fiber may be partially adhered by reducing the sea component ratio of the fiber (A) and the fiber (B) or exposing the island component to the surface by a known spinning technique. preferable.

  The average single fiber fineness of the elastic fiber generated from the fiber (A) is preferably 0.01 to 2 dtex, and more preferably 0.01 to 0.5 dtex. Further, the average fiber diameter of the inelastic ultrafine fibers generated from the fiber (B) needs to be 5 μm or less, preferably 3 μm or less, more preferably 1.5 μm or less. When the average fiber diameter exceeds 5 μm, the texture with softness and fullness is inferior, and when it is made of artificial leather, the overall appearance is very rough, and the texture is smooth and natural leather. It becomes inferior to a high-class feeling such as touch. The lower limit of the average fiber diameter of the fiber (B) is not particularly limited, but is preferably 0.01 μm or more from the viewpoint of color developability and physical properties.

In the present invention, “the elastic fiber is partially porous” means that after extracting or decomposing and removing the inelastic ultrafine fiber, the surface of the artificial leather or a slice plane parallel to the surface is scanned with a scanning electron microscope. When observed, it refers to a state in which 10 to 100% of the elastic fiber surface has a porous structure. The term “elastic fiber fusion” refers to a state in which the elastic polymer is partially bonded to each other or to the elastic polymer of the treatment liquid A by melting the elastic polymer. The degree of fusion of the elastic fiber is evaluated by the density of the fused part. When observed with a scanning electron microscope in the same manner as described above, the density of the fused portions is preferably 1 to 10 locations / 2 mm ² , and more preferably ² to 8 locations / 2 mm ² . Within the above range, even if the obtained artificial leather is repeatedly stretched and deformed, the structural change hardly occurs and the stretchability is excellent. Further, the “network structure” means that at least one other elastic fiber is fused two-dimensionally or three-dimensionally in a branch shape to one elastic fiber, and the at least one other elastic fiber is Furthermore, it refers to a structure in which it is fused or in contact with another elastic fiber. The existence ratio of the network structure is evaluated by the existence density. When observed with a scanning electron microscope in the same manner as described above, the density of the structure is preferably 1 to 50 locations / 5 mm ² , and more preferably 2 to 40 locations / 5 mm ² . Within the above range, even if the obtained artificial leather is repeatedly stretched and deformed, it is substantially free from structural deformation and excellent in elasticity. Preferably, the elastic polymer fiber and the non-elastic polymer fiber are brought into close contact with each other by a method of increasing the ratio of the elastic polymer constituting the fiber (A) by a known spinning technique or a method of exposing the elastic polymer to the surface. By making it easy, it has a structure in which ultrafine fibers made of an inelastic polymer and fibers made of an elastic polymer are partially adhered.

The fiber (B) is transformed into an inelastic ultrafine fiber or a fiber bundle thereof. The elastic fiber and the inelastic ultrafine fiber may be partially adhered by reducing the sea component ratio of the fiber (A) and the fiber (B) or exposing the island component to the surface by a known spinning technique. preferable. The average single fiber fineness of the elastic fiber generated from the fiber (A) is preferably 0.01 to 2 dtex, and more preferably 0.01 to 0.5 dtex. Further, the average fiber diameter of the inelastic ultrafine fibers generated from the fiber (B) needs to be 5 μm or less, preferably 3 μm or less, more preferably 1.5 μm or less. When the average fiber diameter exceeds 5 μm, the texture with softness and fullness is inferior, and when it is made of artificial leather, the overall appearance is very rough, and the texture is smooth and natural leather. It becomes inferior to a high-class feeling such as touch. The lower limit of the average fiber diameter of the fiber (B) is not particularly limited, but is preferably 0.01 μm or more from the viewpoint of color developability and physical properties. The fibers (B) are transformed into ultrafine fibers or fiber bundles made of an inelastic polymer.
Moreover, the porous layer integrated with the entangled nonwoven fabric structure means a state in which an elastic polymer and an inelastic polymer forming the porous layer are mixed and integrated. The method for confirming the porous layer can be confirmed by observing a sliced state in the thickness direction with a scanning electron microscope after extracting or decomposing and removing ultrafine fibers made of an inelastic polymer. Such a structural form of the elastic polymer can be observed as it is in the form of artificial leather, but it is preferable to remove the ultrafine fiber made of the non-elastic polymer by a method that does not swell, dissolve, or melt the elastic polymer. Can be observed easily and clearly. When the inelastic polymer is nylon, it can be removed using a phenol-based solvent.

Hereinafter, the partial porous state of the elastic fibers, the partial fusion of the elastic fibers, and the porous layer integrated with the entangled nonwoven fabric will be further described with reference to the drawings.
FIG. 1 is a drawing-substituting electron micrograph showing a cross section of the artificial leather of the present invention after removing only inelastic ultrafine fibers. In FIG. 1, by removing only ultrafine fibers made of non-elastic polymer from the artificial leather of the present invention, the fiber made of elastic polymer is at least partially porous in the surface layer portion, and further made of fiber made of the elastic polymer. An example of the cross-sectional form which forms the porous layer which fuse | melted partially and was integrated with this entangled nonwoven fabric structure in the surface layer part is shown.
FIG. 2 is a drawing-substitute electron micrograph showing an example of a cross-sectional form of the artificial leather of the present invention. From FIG. 1 and FIG. 2, the artificial leather of the present invention has fibers made of an elastic polymer in at least the surface layer portion of the entangled nonwoven fabric in a porous state, and a part of the elastic polymer is at least one of the artificial leather. It can be confirmed that a porous layer integrated with the entangled nonwoven fabric structure is formed in the surface layer portion.

The artificial leather obtained by making the entangled nonwoven fabric ultrafine may be sliced into a plurality of pieces in a direction parallel to the main surface, if necessary. Napped artificial leather can be obtained by raising the surface of at least one surface of the artificial leather, preferably the surface of the porous layer, to form a raised surface composed mainly of ultrafine fibers. The napped surface is formed by a known method such as buffing with a sand paper. Applying a good solvent for elastic polymer, a solvent or a solution combining a good solvent and a poor solvent or a known binder resin, etc. to the surface by a gravure treatment, spray treatment, coater treatment, etc. By fixing the elastic fiber present in the fiber, it becomes easy to form napped fibers mainly composed of inelastic ultrafine fibers. Such a treatment before the raising treatment is preferable because the writing property and the surface touch become more excellent.
As described above, the napped-tone artificial leather thus obtained is composed of ultrafine fibers made of an inelastic polymer having an average fiber diameter of 5 μm or less and an elastic polymer, and the main body of the elastic polymer is the thickness direction of the artificial leather. A porous structure in which an entangled nonwoven fabric structure is formed with ultrafine fibers made of the inelastic polymer in the form of fibers over the entire layer, and a part of the elastic polymer is integrated with the entangled nonwoven fabric structure on the surface of artificial leather Since it forms a layer, it has good stretchability, texture and drape that are not found in conventional artificial leather, and is excellent in surface touch, lighting effect and appearance.

Moreover, it can also be set as the silver-finished artificial leather by forming a coating layer in the single side | surface of an artificial leather, Preferably, the surface of a porous layer. The thickness of the coating layer is preferably as thin as 10 to 100 μm so as not to impair stretchability, drape, and texture. And since the porous layer which consists of an elastic polymer is formed as a surface layer of artificial leather, even if the thickness of a coating layer is thin, the silver-like artificial leather excellent in surface smoothness is obtained, and also a coating layer A material having excellent peel strength can be obtained.
The artificial leather of the present invention can be applied to a wide range of uses such as clothing, furniture, shoes and bags. In particular, the artificial leather of the present invention is particularly useful in the field of high-grade silver products and high-grade suede products.

Next, embodiments of the present invention will be described by way of examples, but the present invention is not limited to these examples.
In the examples, “part” and “%” relate to mass unless otherwise specified. Moreover, the measurement of average single fiber fineness and each evaluation were performed as follows.

(1) Average fiber diameter The surface or cross section of artificial leather is observed with an electron microscope at a magnification of about 500 to 2000 times to measure the fiber diameter, and the average fiber diameter or average fiber fineness (decitex) is determined from the measured value. Asked. In addition, when the fiber cross section was not circular, the cross-sectional area was converted into a perfect circle and regarded as the fiber diameter.

(2) napping feeling, napping uniformity, color spots, texture Obtained by combining the napping feeling of the raised surface of the artificial leather, the napping uniformity, the overall color spots, touch, flexibility, and fullness. The texture of the artificial leather is evaluated by touching the raised surfaces of the dyed raised artificial leather obtained in the following examples or comparative examples (10 persons) with the appearance and hands of artificial leather. Thus, the case where the target was a high-quality natural leather suede-like smooth and uniform appearance and texture was evaluated in three stages of ○, Δ, and ×, and comprehensive evaluation was made based on these evaluations. Natural leather suede-like smooth appearance, touch and texture were evaluated as A, natural leather suede was slightly inferior to practical use but B was not practically problematic, and case was inferior to natural leather suede and poor in commercial value as C.

Poly-3-methyl-1,5-pentaneadipate glycol having an average molecular weight of 2,000, 4,4′-diphenylmethane diisocyanate, polyethylene glycol and 1,4-butanediol so that the nitrogen percentage based on isocyanate is 4.3% Polyester polyurethane was obtained by melt polymerization. The melt viscosity was 5000 poise. 50 parts of the above polyester-based polyurethane pellets (island component elastic polymer) and 50 parts of low-density polyethylene pellets (sea component) dried to a water content of 50 ppm or less are melt-kneaded with a screw kneader, melt-spun at 230 ° C., and a fineness of 14 dtex. The sea-island type mixed spun fiber (A ₀ ) in which polyurethane is partially present on the surface was obtained. Also, 50 parts of nylon-6 pellets (island component inelastic polymer) and 50 parts of polyethylene pellets (sea component) are melt-kneaded with a screw kneader, melt-spun at 280 ° C., and sea-island mixed spun fiber having a fineness of 10 dtex. (B ₀ ) was obtained. Fiber (A ₀ ) and fiber (B ₀ ) are mixed (mixed) so that the mass ratio of the polyester polyurethane fiber and nylon fiber after ultra-thinning is 40:60, and co-stretched 2.5 times. Then, crimped and cut to obtain staple fibers in which 7 dtex fibers (A ₁ ) and 4 dtex fibers (B ₁ ) each having a fiber length of 51 mm were mixed (mixed).

Next, after the mixed cotton fiber (mixed fiber) is defibrated with a card, it is made into a web with a cross wrap webber and processed with 1500 punch / cm ² with a needle needle of 1 barb, whereby an intertwined nonwoven fabric having a basis weight of 800 g / m ² ( I). This entangled nonwoven fabric (I) was contracted by hot water at 95 ° C. by an area ratio of 30% to obtain an entangled nonwoven fabric (II). Then, after impregnating a water-based polyurethane emulsion composition containing a polyether polyurethane solid content concentration of 2% (amount of polyurethane applied to the entangled nonwoven fabric (II) 1%) and heat treatment, the entangled nonwoven fabric (II ) Is dried and dried in a dryer to soften the sea component polyethylene and partially bond the fibers to have a thickness of 2.63 mm, a basis weight of 1040 g / m ² and a density of 0.395 g / cm ^3. A good entangled nonwoven fabric (III) was obtained.

Next, a 4% solution of polycarbonate-based polyurethane dissolved in a DMF solvent was applied on both sides of the entangled nonwoven fabric (III) by 250 g / m ² by a roll coater method, and then poured into a 40% CMF 30% DMF aqueous solution. The DMF present in the entangled nonwoven fabric was further replaced with water by washing with water. Next, the polyethylene in the fiber (A ₁ ) and fiber (B ₁ ) is dissolved and removed in a 90 ° C. hot toluene bath (extra fine fiber treatment), and is present in the entangled nonwoven fabric in 90-100 ° C. hot water. Toluene was azeotroped with water, replaced with water, and dried while being set to a predetermined width to obtain artificial leather (I) having a thickness of about 1.3 mm.
In the obtained artificial leather (I), the average fiber diameter of the ultrafine fibers made of nylon is about 1.1 μm, and when the surface and the cross section are observed with an electron microscope, the fibers made of polyurethane are partially porous. In addition, there are places where the fibers are partly fused together, and an entangled nonwoven fabric structure is formed with ultrafine fibers made of nylon over the entire artificial leather layer, and both the front and back sides of the artificial leather are made of polyurethane. A porous layer in which a part of the layer was integrated with the entangled nonwoven fabric structure was observed. Furthermore, a state in which the polyurethane fibers are partly in close contact with the nylon ultrafine fibers was observed throughout the entire artificial leather layer, particularly in the surface layer portion.

This artificial leather (I) is divided into two slices at the center in the thickness direction, and the divided surface is first ground by a buffing machine using a sandpaper of abrasive grain number # 180 to obtain a thickness of 0.50 mm. Then, the opposite side of the dividing surface (that is, the surface side before dividing) was subjected to raising treatment with a buffing machine using sandpaper with abrasive grain number # 400 to obtain undyed napped artificial leather. Next, the napped-tone artificial leather was dyed brown under the following conditions, and further subjected to a stagnation treatment and a hair styling treatment with a brushing roll.
Dyeing machine Wins dye Ilgaran Brown 2RL (Ciba Specialty Chemicals Co., Ltd.) owf 4%
Irgaran Yellow 2GL (Ciba Specialty Chemicals Co., Ltd.) owf 1%
Auxiliary agent Leberan NK-D (manufactured by Maruhishi Oil Chemical Co., Ltd.)
Bath ratio 1:20
Dyeing temperature x time 90 ° C x 60 minutes

  After brushing the napped leather-like sheet dyed brown, the brown napped leather-like sheet excellent in draping property was obtained by stretching the hair with a brushing roll. The obtained napped leather-like sheet was excellent in stretchability, and no structural change occurred even when the 30% elongation was repeated 10 times. In addition, it had a soft and fulfilling texture and excellent drape. The other evaluation results are shown in Table 1.

A 20% solution of a polycarbonate-based polyurethane dissolved in a DMF solvent was coated on each side of the entangled nonwoven fabric (III) obtained in Example 1 by 500 g / m ² as a silver surface layer by a roll coater method. The solution was put into a 30% aqueous solution of DMF and further washed with water to replace DMF present in the entangled nonwoven fabric with water. Next, after the polyethylene in the fiber (A ₁ ) and the fiber (B ₁ ) is dissolved and removed in a 90 ° C. toluene bath, the toluene present in the entangled nonwoven fabric in hot water at 90 to 100 ° C. is mixed with water. It was azeotropically substituted with water and dried while being set to a predetermined width to obtain an artificial leather with a silver thickness of about 1.3 mm.

  In the obtained artificial leather with silver, the average fiber diameter of the ultrafine fibers made of nylon is about 1.1 μm, and when the surface and cross section are observed with an electron microscope, there is a foamed silver surface layer of coated polyurethane, The fibers made of polyurethane in the entangled nonwoven fabric under the silver layer are partially porous, and the fibers are partially fused, and the whole entangled nonwoven fabric portion of the artificial leather The entangled nonwoven fabric structure was formed with ultrafine fibers made of nylon. Further, a structure in which a porous layer in which a part of polyurethane was integrated with the entangled nonwoven fabric structure was observed under the silver surface layer of the artificial leather. Furthermore, the state in which the fibers made of polyurethane are partly in close contact with the nylon ultrafine fibers is observed in various places throughout the entangled nonwoven fabric of artificial leather, especially under the silver layer and opposite to the silver layer of the entangled nonwoven fabric. It was observed intensively in the back layer part. The evaluation results are shown in Table 2.

  100 parts of silicon-modified polyether polyurethane (Dai Nippon Ink Chemical Co., Ltd., NY214, 100% modulus 40%, solid content 20%) as a coating layer on a release paper with grain (Lintec Corporation TP R-8) The polyurethane resin solution consisting of 20 parts of black pigment (Dailac L6910N, manufactured by Dainippon Ink and Chemicals, Inc.), 30 parts of DMF, and 30 parts of methyl ethyl ketone was applied so that the average thickness of the coating layer after drying was 40 microns. The coating layer was obtained by heating at 100 ° C. for 5 minutes. On top of that, a two-component curable polyether-based polyurethane solution is applied so that the average thickness of the adhesive layer after drying is 30 microns, dried at 50 ° C. for 3 minutes, and the coated surface is still sticky. In the state where the artificial leather (I) of Example 1 is divided into two parts at the center in the thickness direction, the divided surface is ground by a buffing machine in which sandpaper of abrasive grain number # 180 is set. The film was pasted with a thickness of 0.50 mm, dried at 100 ° C. for 2 minutes, and then allowed to stand at 40 ° C. for 3 days, after which the release paper was peeled off. Further, in order to impart flexibility, a softening agent (Nikka Silicon AM-204, solid content 20%) manufactured by Nikka Chemical Co., Ltd. was impregnated with a 5% aqueous solution so that the impregnation rate was 50%, and a tumbler dryer was used at 70 ° C 40 Treated for minutes. The obtained artificial leather with silver has not only excellent drape while having a soft texture and elasticity, but also excellent surface smoothness and excellent peel strength even with an extremely thin coating layer. It was a thing. The other evaluation results are shown in Table 2.

Comparative Example 1
The entangled nonwoven fabric (III) obtained in Example 1 was impregnated in a 4% solution of polycarbonate polyurethane dissolved in a DMF solvent, and then poured into a 30% aqueous DMF solution at 40 ° C. and further washed with water to entangle the nonwoven fabric. The DMF present therein was replaced with water. Next, after the polyethylene in the fiber (A ₁ ) and the fiber (B ₁ ) is dissolved and removed in a 90 ° C. toluene bath, the toluene present in the entangled nonwoven fabric in hot water at 90 to 100 ° C. is mixed with water. It was azeotroped, replaced with water, and dried while being set to a predetermined width to obtain an artificial leather having a thickness of about 1.3 mm.
In the obtained artificial leather, the average fiber diameter of the ultrafine fibers made of nylon is about 1.1 μm, and when the surface and cross section are observed with an electron microscope, the fibers made of polyurethane are partially porous in all layers. In addition, while forming an entangled nonwoven fabric structure with ultrafine fibers made of nylon over the entire layer, a network structure in which the fibers are partially fused was formed. Furthermore, the state in which some of the fibers made of polyurethane were in close contact with the nylon ultrafine fibers was observed throughout the artificial leather.
The obtained artificial leather was subjected to split treatment, split surface grinding treatment, surface raising treatment, dyeing treatment, kneading treatment, and hair styling treatment in the same manner as in Example 1 to obtain napped artificial leather. This napped-tone artificial leather was inferior in smoothness compared to Example 1, and the level of stretchability and drape did not reach the level of Example 1. The other evaluation results are shown in Table 1.

Comparative Example 2
A 4% solution of polycarbonate polyurethane dissolved in a DMF solvent was artificially coated with a thickness of about 1.3 mm in the same manner as in Example 1 except that the entangled nonwoven fabric (III) was not impregnated, coagulated, and washed with water. Got leather. When the surface and cross section of the obtained artificial leather are observed with an electron microscope, the fibers made of an elastic polymer are in a non-porous state, and the fibers made of the elastic polymer are not fused together. Did not have.
This artificial leather was divided into two in the thickness direction, and the divided surface was ground with a buffing machine to obtain an artificial leather having a thickness of 0.52 mm. The side opposite to the divided surface of the artificial leather was brushed with sandpaper having an abrasive grain count of # 400 to obtain undyed napped artificial leather. The obtained napped-toned artificial leather had unstable napped state and low processability.
Thereafter, dyeing was carried out under the same dyeing conditions as in Example 1 to obtain a velor napped artificial leather with a brown fluffy appearance and a rough fluffy appearance and a rough appearance. The obtained napped-tone artificial leather was excellent in drape and stretchability, but its form stability after repeated 30% elongation was inferior to that in Example 1. The texture was flexible but lacked in fulfillment. The evaluation results are shown in Table 1.

Comparative Example 3
Defibered with a card using all 4 dtex short fibers (B ₁ ), then formed into a web with a cross-wrap webber, and then processed with a 1 barb needle punch needle at 1500 punches / cm ^2. Thus, an intertwined nonwoven fabric having a basis weight of 800 g / m ² was obtained. The obtained entangled nonwoven fabric is heat-treated with a drier to soften the sea component polyethylene to partially bond the fibers to have a thickness of 2.65 mm, a basis weight of 850 g / m ² and a density of 0.32 g / cm ³ . A composite nonwoven fabric (III) was obtained. The entangled nonwoven fabric was impregnated with a 13% DMF solution of polyether polyurethane, and then poured into a 30% aqueous DMF solution at 40 ° C., and further washed with water to replace the DMF present in the entangled nonwoven fabric with water. Next, after the polyethylene in the fiber (B ₁ ) is dissolved and removed in a 90 ° C. toluene bath, the toluene present in the entangled nonwoven fabric is azeotroped with water in hot water at 90 to 100 ° C. Substituting and drying while being set to a predetermined width provides an artificial leather in which non-fibrous polyurethane is present in a porous state in the entangled space of the entangled nonwoven fabric made of nylon 6 ultrafine fibers having a thickness of 1.3 mm. It was. When the ultrafine fibers of nylon 6 were dissolved and removed from this artificial leather, a foamed sheet made of polyurethane was obtained. The average fiber diameter of the ultrafine fibers of nylon 6 in the obtained artificial leather is about 1.1 μm, and when the surface and cross section are observed with an electron microscope, there is a polyurethane having a fibrous structure as described above. I did not.
The obtained artificial leather was subjected to split treatment, split surface grinding treatment, surface raising treatment, dyeing treatment, kneading treatment, and hair styling treatment in the same manner as in Example 1 to obtain napped artificial leather. This napped-tone artificial leather was inferior in elasticity and drape. The evaluation results are shown in Table 1.

Comparative Example 4
The artificial leather obtained in Comparative Example 2 was dry-formed in the same manner as in Example 3. The obtained artificial leather was inferior in unity and smoothness as compared with Example 3. The evaluation results are shown in Table 2.

The drawing substitute electron micrograph which shows one example of the cross-sectional form after removing only the fiber which consists of an inelastic polymer of the artificial leather of this invention. The drawing substitute electron micrograph which shows an example of the cross-sectional form of the artificial leather of this invention.

Claims (6)

An artificial leather comprising an ultrafine fiber made of an inelastic polymer having an average fiber diameter of 5 μm or less and an elastic polymer, wherein the elastic polymer is mainly composed of the inelastic polymer in the form of a fiber over the entire thickness direction of the artificial leather. And a part of the elastic polymer is integrated with the entangled nonwoven structure on at least one surface of the artificial leather and forms a continuous porous layer in the surface direction. Artificial leather characterized by The artificial leather according to claim 1, wherein the elastic polymer in a fiber form is partially porous. The artificial leather according to claim 1 or 2, wherein the ultrathin fiber made of an inelastic polymer and the fiber made of an elastic polymer are partially adhered. The napped-tone artificial leather in which the napped | maintenance mainly composed of the ultrafine fiber which consists of an inelastic polymer is formed in the surface in which at least the porous layer of the artificial leather of any one of Claims 1-3 was formed. The artificial leather with silver which has a coating layer in the surface in which at least the porous layer of the artificial leather of any one of Claims 1-3 was formed. The manufacturing method of artificial leather characterized by sequentially performing the following steps I to III.
I. At least a part of the fiber made of an elastic polymer is present on the surface and a fiber (A) capable of generating a fiber made of the elastic polymer and a fiber capable of generating an ultrafine fiber made of an inelastic polymer having an average fiber diameter of 5 μm or less ( A step of producing an entangled nonwoven fabric comprising B),
II. A liquid containing at least a good solvent for the elastic polymer is applied to at least one surface of the entangled nonwoven fabric, and at least the elastic polymer in the fiber (A) present in the surface layer portion is partially dissolved, and then the Applying a liquid containing at least a poor solvent for the elastic polymer, and III. A step of generating fibers made of an elastic polymer and ultrafine fibers made of an inelastic polymer having an average fiber diameter of 5 μm or less from the fibers (A) and (B), respectively.

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