JP2001214378A - Leather-like sheet and method for producing the same - Google Patents

Abstract

(57) [Summary] [Problem] To provide a leather-like sheet having uniform elongation elasticity, extremely softness, low resilience and a sense of fulfillment as a stretchable nonwoven fabric. SOLUTION: An ultrafine fiber bundle A made of an elastic polymer dispersed in an ultrafine fiber bundle made of an inelastic polymer and a nonwoven fabric in which an ultrafine fiber bundle B made of an inelastic polymer are three-dimensionally entangled are mainly used. A leather-like sheet characterized in that the three-dimensional entangled structure formed by the ultrafine fiber bundle B is more relaxed than the three-dimensional entangled structure formed by the ultrafine fiber bundle A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leather-like sheet having elasticity and a texture very similar to natural leather. More specifically, the present invention does not substantially cause structural deformation even when repeatedly subjected to elongation deformation, that is, it has a flexible and fulfilling texture without resilience, having excellent elasticity and fiber entanglement. And a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, as a method of obtaining an entangled nonwoven fabric having excellent elasticity from an elastic fiber, a nonwoven fabric obtained by depositing short fibers obtained by flash-spinning polyurethane and adhering fiber intersections by self-adhesion or the like is known. Or JP-A-52-8177
As described in Japanese Unexamined Patent Publication, a long-fiber nonwoven fabric of polyurethane obtained by a spun bond method is known. However, in the case of these polyurethane nonwoven fabrics, since the fibers themselves are too strong and too flexible, it is difficult to form a sufficient fiber entangled body by a conventionally known entanglement such as needle punching or a fluid jet method.

[0003] For example, Japanese Patent Application Laid-Open No. 48-18579 discloses that elastic fibers 5 to 5 are elastic fibers.
A nonwoven fabric obtained by mixing 80% by weight with an inelastic fiber has been proposed. However, since elastic fibers differ in rigidity and elongation elasticity so as to be incomparable with inelastic fibers, it is extremely difficult to mix fibers sufficiently to obtain a good web with a card machine, and furthermore to obtain good bonding. It is. Japanese Patent Application Laid-Open No. 52-85575 describes a method of forming an entangled nonwoven fabric using a composite fiber comprising an inelastic polymer and an elastic polymer, and then peeling the nonwoven fabric from each component polymer. And the inelastic polymer are constrained in the same state, and therefore cannot have sufficient elasticity structurally.

[0004] Japanese Patent Publication No. 40-2792 discloses a nonwoven fabric obtained by blending a mixed spun fiber comprising an elastic polymer and an inelastic polymer, and dissolving the elastic polymer in the fiber constituting the obtained nonwoven fabric. Thereafter, a method of resolidifying the elastic polymer in the nonwoven fabric has been proposed. With this method, a nonwoven fabric having good entanglement can be obtained, but none of the nonwoven fabric has sufficient elasticity because the elasticity of the nonwoven fabric is governed by fibers made of an inelastic polymer.

[0005] As an example using a microelastic fiber bundle obtained by extracting and removing a sea component, Japanese Patent Publication No. 41742/1994 discloses an ultrafine elastic fiber bundle obtained by removing one component from a conjugate fiber and an inelastic fiber. There has been proposed a stretchable non-woven fabric in which pulp and cotton are mixed. Although this nonwoven fabric is excellent in entanglement, the ultrafine fiber bundle composed of only the ultrafine elastic fibers is difficult to obtain the effect as the ultrafine fibers because the adhesion between the microfine elastic fibers is easily generated, and the product specific gravity is high and hard. You can get only the texture.

Japanese Unexamined Patent Publication (Kokai) No. 61-201086 discloses that a sea component is removed from a nonwoven fabric of a composite sea-island fiber in which an ultrafine fiber made of an inelastic polymer and an ultrafine fiber made of an elastic polymer are present in the same sea component. Although it is described about a sheet that partially dissolves microfibers made of an elastic polymer and serves as a binder, the specific gravity of the elastic polymer becomes too high by bundling and bonding the ultrafine fiber bundles made of an inelastic polymer,
The soft texture of the ultrafine fibers cannot be obtained, and the elastic polymer is an ultrafine fiber, so that the stress becomes small and the desired high elasticity cannot be obtained.

[0007] Japanese Patent Application Laid-Open No. Hei 5-339863 discloses that an ultrafine fiber bundle made of an elastic polymer and an ultrafine fiber bundle made of an inelastic polymer remove sea components from a nonwoven fabric of a composite sea-island fiber having a side-by-side structure. Although a sheet is described in which a part of the ultrafine fibers is dissolved and used as a binder, bundle adhesion occurs in the ultrafine fiber bundle made of the elastic polymer and the specific gravity becomes too high, so that a soft texture of the ultrafine fibers can be obtained. In addition, since the elastic polymer is an ultrafine fiber, the stress is reduced, and the desired elasticity is not obtained.

Further, Japanese Patent Application Laid-Open No. 5-339864 discloses that ultrafine fiber bundles composed of an elastic polymer and an inelastic polymer are obtained by removing sea components from a nonwoven fabric of a composite sea-island fiber having a side-by-side structure to form ultrafine fibers composed of an elastic polymer. JP-A-60-31121 describes a sheet in which a core component composed of an elastic polymer and a microfiber component composed of an inelastic polymer are present in a sea component. A sheet obtained by removing a sea component from a nonwoven fabric of a composite core-sheath fiber comprising the components described in JP-A-63-31806.
Patent Document 7 discloses a sheet obtained by shrinking only an elastic polymer component of a nonwoven fabric in which an ultrafine fiber bundle or a fiber having a fine space made of an elastic polymer and a microfine fiber bundle or a fiber having a fine space made of an inelastic polymer are mixed. However, in these methods, since the elastic polymer having elasticity is structurally constrained by the inelastic polymer, not only cannot it have sufficient elasticity, but also the elastic polymer has a high density. Due to the presence in the sheet, the specific gravity becomes too high and a soft texture cannot be obtained.

Japanese Patent Application Laid-Open No. 61-15 / 1986 discloses an example in which elastic fibers, shrinkable inelastic fibers and non-shrinkable inelastic fibers are mixed.
No. 7632 describes a sheet obtained by subjecting a nonwoven fabric containing a mixture of a fiber bundle made of an elastic polymer, a contractile fiber made of an inelastic polymer, and a non-shrinkable fiber made of an inelastic polymer to a shrinkage treatment. After the shrinkage treatment causes the inelastic fibers with strong shrinkage to shrink in the non-woven structure, the elastic fiber bundles with weak shrinkage exist in a loose state in the non-woven structure, resulting in insufficient recovery after elongation. In addition, each of the non-elastic fibers is thick, and adhesion or sticking within the elastic fiber bundle cannot be suppressed, so that a soft texture cannot be obtained as a sheet. As described above, at present, a leather-like sheet having good workability and texture and elasticity has not been obtained.

[0010]

According to the known nonwoven fabric manufacturing methods, the leather has both entanglement and elasticity, and has a soft and rich texture without repulsion. No sheet was obtained. SUMMARY OF THE INVENTION An object of the present invention is to provide a leather-like sheet having uniform elongation elasticity, extremely softness, a small repulsion feeling and a feeling of fulfillment as a stretchable nonwoven fabric.

[0011]

According to the present invention, there is provided an ultrafine fiber bundle A in which ultrafine fibers made of an elastic polymer are dispersed in an ultrafine fiber bundle made of an inelastic polymer, and an ultrafine fiber bundle B made of an inelastic polymer. A leather-like sheet mainly composed of a three-dimensionally entangled nonwoven fabric, wherein the three-dimensional entangled structure formed by the ultrafine fiber bundle B is more relaxed than the three-dimensional entangled structure formed by the ultrafine fiber bundle A. Leather-like sheet. Further, the present invention also provides a highly shrinkable ultrafine fiber-generating fiber a in which an island component made of an elastic polymer is dispersed in a dispersion medium component containing an island component having a contraction ability made of an inelastic polymer, and an island component made of an inelastic polymer A step of preparing an entangled nonwoven fabric using the low-shrinkage ultrafine fiber-generating fibers b, a step of shrinking the entangled nonwoven fabric, a step of transforming the ultrafine fiber-generating fibers into ultrafine fibers, and a leather-like surface A method for producing a leather-like sheet, comprising a step of finishing.

That is, the microfiber-generating fiber a used in the present invention is a fiber having a structure in which island components made of an elastic polymer are dispersed in a sea component containing island components having a contractile ability made of an inelastic polymer. As a method of producing such a fiber, in a method of spinning a multi-core sheath fiber, a non-elastic polymer and an elastic polymer are used by using a spinning nozzle arranged so that a two-component core component is uniformly distributed in a fiber cross section. In the method of spinning by supplying each as a core component so as to be uniformly distributed in the fiber cross-section, an elastic polymer is supplied to the core component in the spinning method of the multi-core sheath fiber, and the inelastic fiber component polymer is used as the sheath component. There is a method of spinning by mixing and melting the chips of the sea component polymer, and if it is desired to obtain good elasticity, the elastic polymer is supplied to the core component in a multi-core sheath fiber spinning method, A preferred method is to mix and melt the chips of the inelastic fiber component polymer and the sea component polymer into the sheath component, and then supply and spin.

In this method, since the non-elastic fiber having contractility has a discontinuous structure in the length direction of the core-sheath fiber, a moderate displacement occurs between the non-elastic fibers having contractility when the core-sheath fiber elongates. This makes it easier to obtain a sheet with higher elongation. In addition, since the elastic fiber has a continuous structure in the length direction of the core-sheath fiber, the recovery force after the elongation of the core-sheath fiber becomes larger. The cross-sectional shape of the microfiber-generating fiber a may be a circular cross-section, an elliptical cross-section, a cocoon-shaped or other irregular cross-section, or a hollow fiber. In any case,
Any fiber may be used as long as it has a cross-sectional shape such that the elastic microfine fiber component is uniformly dispersed among the inelastic microfine fiber components having shrinkability uniformly dispersed in the sea component.

The preferred weight ratio of the inelastic ultrafine fiber component to the elastic ultrafine fiber component in the ultrafine fiber generating fiber a is 95/5.
５5/95, more preferably 85 / 15-30 / 70
It is. If the inelastic fiber exceeds 95%, the resulting sheet lacks flexibility, the elastic fiber is less likely to stick, and the fiber is less likely to stick out. It becomes something. By removing the sea component polymer constituting the microfine fiber-generating fiber a, the microfine fiber bundle A in which the microfine fibers made of the elastic polymer are dispersed and present in the microfine fiber bundle made of the inelastic polymer is formed.

The fineness of the ultrafine fibers constituting the ultrafine fiber bundles A is preferably 0.5 dtex or less, particularly preferably 0.1 dtex or less, and 0.001 dtex or more. If the single fiber fineness exceeds 0.5 decitex, the resilience is large and the texture becomes hard. In the present invention, the ratio of the thickness of the ultrafine fibers made of the inelastic polymer constituting the ultrafine fiber bundle A to the thickness of the ultrafine fibers made of the elastic polymer is preferably in the range of 1:10 to 1:50. The thickness of the ultrafine fibers referred to in the present invention is obtained by taking a micrograph of a cross section of the ultrafine fiber bundled fiber in a plane perpendicular to the fiber axis direction, and calculating the total decitex of the ultrafine fibers constituting the bundle by the microfine fiber. It is obtained by dividing by the number.

The ratio of the number of the ultrafine fibers made of the inelastic polymer constituting the ultrafine fiber bundled fiber A to the number of the ultrafine fibers made of the elastic polymer is 10: 1 to 50: 1 is preferred. The number of the ultrafine fibers constituting the ultrafine fiber bundles A is preferably 50 to 1000, as counted from a micrograph of the fiber cross section. In the present invention, the island component polymer composed of the inelastic polymer constituting the microfine fiber-generating fiber a needs to have high shrinkability, and specifically, the microfine fiber-generating fiber b
Is preferably 2 to 30 times the shrinkage ratio of the island component polymer composed of the inelastic polymer which constitutes the above, from the viewpoint of relaxing the microfine fiber bundle B and increasing the range of expansion and contraction.

The elastic polymer in the present invention means a polymer having a stretch elastic recovery of 50% or more after 1 minute when the polymer is formed into a fiber and the fiber is stretched by 50% at room temperature. The inelastic polymer means a polymer whose elongation elastic recovery measured in the same manner is less than 50% or whose critical elongation does not reach 50% at room temperature.

Examples of the inelastic polymer used for the island component of the ultrafine fiber-generating fiber a include polyethylene terephthalate or a copolymer based on it, polybutylene terephthalate or a copolymer based on it,
Polymers that can generate shrinkage, such as spinnable polyesters such as aliphatic polyesters or copolymers thereof, copolymerized nylons represented by nylon 610 and nylon 612, and other spinnable polyamides can be used. Fibers having shrinkage can be obtained by drawing the raw yarns obtained using these polymers in a low-temperature bath at 40 to 60 ° C and then drying at a low temperature of 50 ° C or lower.

On the other hand, examples of the elastic polymer used for the island component of the microfiber-generating fiber a include polymer diols having an average molecular weight of 500 to 3500 such as polyester diol, polyether diol, polyester ether diol, polylactone diol, and polycarbonate diol. A conjugated diene polymer or conjugated diene polymer block such as a polyurethane, polyisoprene, or polybutadiene obtained by reacting at least one selected from the group consisting of an organic diisocyanate and a chain extender having two active hydrogen atoms. And other polymers that can be spun and exhibit the above-mentioned rubber elastic behavior.

The polymer constituting the sea component of the microfiber-generating fiber a is a polymer having a different solubility or degradability in a specific solvent or decomposer from the highly shrinkable inelastic polymer and the elastic polymer of the island component. In addition, there are used those which have a thermoforming temperature range that does not cause a reaction or interaction between these polymers in a melted state, which would hinder spinning within a time required for spinning.
For example, polyethylene, polypropylene, ethylene propylene copolymer, ethylene vinyl acetate copolymer, polystyrene, styrene acrylic copolymer, at least one polymer selected from polymers such as styrene ethylene copolymer, spinnability, nonwoven fabric It is appropriately selected in consideration of the prevention of fiber cracking in the production process, the ease of selecting a solvent or a decomposer used for ultrafine treatment, and the like.

The ultrafine fiber generating fiber b used in the present invention is:
It is a fiber having a structure having island components composed of an inelastic polymer. Examples of a method for producing such a fiber include a method of spinning using a multi-core sheath fiber spinning nozzle, a method of mixing and melting and feeding a chip of an inelastic fiber component polymer and a sea component polymer, and spinning. is there. The cross-sectional shape of the fiber may be a circular cross-section, an elliptical cross-section, a cocoon-shaped or other irregular cross-section, or a hollow fiber. In any case,
Any fiber having a cross-sectional shape in which the inelastic ultrafine fiber component is uniformly dispersed in the sea component may be used. By removing the sea component polymer from the ultrafine fiber-generating fibers b, an ultrafine fiber bundle B made of an inelastic polymer is formed. The number of island components existing in the cross section of the ultrafine fiber generating fiber b is 15 to 100
Zero is preferred.

The fineness of single fibers of the ultrafine fibers constituting the ultrafine fiber bundle B is preferably 0.5 dtex or less, particularly preferably 0.1 dtex or less and 0.001 dtex or more. If the single fiber fineness exceeds 0.5 decitex, the resilience is large and the texture becomes hard.

The low-shrinkage inelastic polymer constituting the island component used for the microfine fiber-generating fiber B is, for example, polyethylene terephthalate or a copolymer based on it, polybutylene terephthalate or a copolymer based on it, or a fat. Polyesters such as aromatic polyesters or copolymers thereof, nylons 6, nylon 66, nylon 610, nylon 612, nylons represented by nylon 12, other spinnable polyamides, polyethylene, polypropylene, polybutylene, etc. Polyolefins, acrylic copolymers, polyvinyl alcohol and the like. The raw yarn obtained using these polymers is drawn in a high-temperature bath at 80 to 95 ° C, and then drawn at 100 to 1 ° C.
After setting the fixed length at 30 ° C., the fiber is dried at 80 to 100 ° C. to obtain a fiber with low shrinkage.

As the polymer constituting the sea component used for the microfiber-generating fiber b, the same polymer as the sea component of the microfiber-generating fiber a can be used.

The obtained ultrafine fiber-generating fibers a and b are subjected to processing steps such as drawing, heat setting, crimping, cutting, and opening by a conventionally known method to produce raw cotton. Such raw cotton is defibrated with a card after blending and formed into a random web or a cross wrap web with a weber. The webs are laminated as needed to the desired weight. The weight of the web varies depending on the intended use, but is generally 100-
A range of 3000 g / m2 is preferred.

In this case, the mixing amount of the microfine fiber-generating fibers a and b is determined by the ratio of the inelastic microfine fiber component and the elastic microfine fiber component in the entire fiber component when the sea component is removed from the microfine fiber generating fibers a and b. 95/5 to 5/95 in a suitable weight ratio
And more preferably in the range of 85/15 to 30/70, and the ultrafine fiber bundle A in the entire inelastic fiber component
The preferred ratio of the inelastic fiber component in the inside and the inelastic fiber component in the microfine fiber bundle B is 90/10 to 10/90, more preferably in the range of 80/20 to 20/80. If the total non-elastic ultrafine fiber component ratio exceeds 95%, the sheet obtained lacks flexibility, the elastic fibers are less likely to stick, and the fibers are liable to come off. On the other hand, if it is less than 5%, the texture is soft. However, it has low strength and is rubber-like. Further, when the ratio of the inelastic fibers in the ultrafine fiber bundle A in all the inelastic fiber components exceeds 90%, the specific gravity of the sheet increases and the sheet lacks flexibility, and the desired elasticity can be obtained. On the other hand, if it is less than 10%, the texture becomes soft, but the contraction of the microfiber-generating fiber a becomes weak, so that the desired elasticity cannot be obtained.

Next, a fiber entangled nonwoven fabric is formed by performing a fiber entanglement treatment by a known means. A preferred entanglement treatment is a needle punching method or a high-pressure water jet method. The number and conditions of the needle punches vary depending on the shape of the needle used and the thickness of the web, but are generally set in the range of 200 to 2500 punches / cm 2. If the needle punching conditions are too strong, the fiber cutting will increase rather than the fiber entanglement effect, causing structural destruction and increasing the web area,
This leads to a decrease in physical properties such as tear strength. When the entanglement is insufficient, physical properties such as peel strength of the obtained sheet are reduced, and the crimping when bending is deteriorated and the sense of fulfillment is insufficient.

In order to impart sufficient elasticity to the leather-like sheet obtained in the present invention and obtain flexibility, it is necessary to shrink the fiber-entangled nonwoven fabric. The degree of shrinkage is such that the area shrinkage ratio after shrinkage with respect to the area of the nonwoven fabric before shrinkage treatment is 10 to 50.
%. In this shrinkage treatment, it is preferable that the elastic fiber component shrinks more than the inelastic fiber component, which is the island component of the highly shrinkable microfine fiber-generating fiber a, but the shrinkage force of the elastic fiber component has a shrinking ability. It is weaker than the shrinkage force of the inelastic fiber component, and it is actually difficult to obtain sufficient shrinkage against the tension applied during the process.

In the present invention, the ultrafine fiber generating fiber a
Using the nonwoven fabric obtained by mixing the ultrafine fiber generating fiber b with the inelastic fiber in the microfine fiber generating fiber a, the microfine fiber generating fiber a is highly shrunk. The inelastic fiber component in the ultrafine fiber generating fiber a having a low contraction force due to the shrinkage of the ultrafine fiber generating fiber a present in the nonwoven fabric structure in a relaxed state, and the shrinkage-treated ultrafine fiber generating fiber a Since the elongation of the sheet increases in accordance with the amount of shrinkage, at the time of elongation of the sheet, high elongation is realized by utilizing the high shrinkage of the inelastic fibers in the microfine fiber bundle A and the displacement between the fibers. The dimensional stability of the sheet at the elongation limit is realized by the ultrafine fiber bundle B with low shrinkage, and the elongation recovery of the sheet is realized by using the recovery force of the elastic fibers in the ultrafine fiber bundle A. If the contracting force of the inelastic fiber component dispersed in the microfiber-generating fiber a is low, the inelastic fiber component will be in a state of tension even if the contraction treatment is performed under the condition that only the dispersed elastic fiber component also contracts. Although the ultrafine fiber-generating fiber a does not sufficiently shrink as a single fiber, in the present invention, the inelastic fiber component in the ultrafine fiber-generating fiber a has a high shrinkage, so that it is stable with the elastic fiber component. A good contractility can be obtained.

As described above, in the present invention, since the microfine fiber-generating fiber a has a higher contractile ability than the microfine fiber-generating fiber b, this state is inelastic when the sea component is removed later. The ultrafine fiber bundle B made of a polymer is in a relaxed state in the entangled nonwoven fabric structure, and the desired sheet elasticity and form stability and flexibility at the limit of elongation can be obtained. If the area shrinkage of the fiber-entangled nonwoven fabric is less than 10%, the desired elasticity cannot be obtained, and if it exceeds 50%, the apparent specific gravity of the nonwoven fabric becomes too high, so that a sheet having a soft texture cannot be obtained. .

The shrinkage rate of the microfiber-generating fiber a satisfying the above is 10% or more, preferably 20% or more. When the shrinkage rate of the microfiber-generating fiber a is less than 10%, the texture is soft, but the feeling of fulfillment is small, and the microfiber-generating fiber b exists in a contracted nonwoven fabric in a tensioned state. This makes it difficult to obtain the desired elasticity. The shrinkage rate of the microfiber-generating fiber b is 50% or less, preferably 30% or less of the shrinkage rate of the microfiber-generating fiber a. When the shrinkage rate of the microfine fiber-generating fiber b exceeds 50% of the shrinkage rate of the microfine fiber-generating fiber a, the microfine fiber-generating fiber b exists in a tensioned state in the fiber entangled nonwoven fabric structure after the shrinkage treatment. As a result, the texture becomes hard and it becomes difficult to obtain the desired elasticity.

Further, shrinking the microfiber-generating fiber a in the state of a non-woven fabric mixed with the microfiber-generating fiber b not only causes relaxation of the microfiber-generating fiber b in the nonwoven fabric structure. The elongation of the microfiber-generating fiber a increases in accordance with the amount of shrinkage as compared with the state before shrinkage, and thus has the effect of increasing the elongation of the sheet. The elongation of the ultrafine fiber generating fiber a after the shrinkage treatment is 60% or more, preferably 80% or more. When the elongation of the ultrafine fiber-generating fiber a after the shrinkage treatment is less than 60%, desired elasticity cannot be obtained. Further, since the ultrafine fiber generating fiber b exists in a relaxed state in the nonwoven fabric structure after the shrinkage treatment, the effect of the elongation of the ultrafine fiber generation type fiber b after the shrinkage treatment on the elasticity of the sheet is extremely small. Although it is small, if the elongation of the ultrafine fiber-generating fiber b after the shrinkage treatment is too low, the texture of the sheet is adversely affected.

Next, the fiber-entangled nonwoven fabric after the shrinkage treatment is treated with a solvent or a decomposer that does not dissolve or remarkably swell the ultrafine fiber components in the ultrafine fiber generating fibers a and b, thereby obtaining the ultrafine fiber generating fibers. The ultrafine fiber bundles A and B are generated by removing the sea components a and b.

As one embodiment of the final leather-like sheet,
It is also possible to make the fiber entangled nonwoven fabric contain a binder resin. By incorporating a binder resin, the properties of the leather-like sheet can be changed. Accordingly, the applied binder resin may be an elastic polymer or an inelastic polymer, or a polymer occupying an intermediate region between the two. However, when an artificial leather having high flexibility and elasticity is desired, it is preferable to use an elastic polymer. The content of the binder resin is appropriately increased or decreased depending on the elastic properties of the resin or the feeling of the intended final product, but is preferably 5% or less based on the ultrafine fiber component. If the amount of the binder resin is too large, the apparent specific gravity of the sheet becomes high, resulting in a paper-like or firm texture, a rubber-like resilience, and poor elasticity.

Specific examples of the elastic polymer used as the binder resin include polyester-based polyurethane,
Polyurethanes such as polyether polyurethane, polyester ether polyurethane, polylactone polyurethane, and polycarbonate polyurethane; polymers or copolymers of acrylic acid or acrylate; conjugated diene polymers or conjugated dienes such as polyisoprene and polybutadiene Examples of the polymer include polymers having a polymer block in the molecule, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, vinyl acetate polymer, and copolymer. When it is desired to use a resin having a small elastic behavior as a binder resin, a plasticized polymer of a vinyl chloride polymer or copolymer, polyamide or modified polyamide, ethylene-
Polymers such as a vinyl acetate copolymer are exemplified.

One or more of these polymers are selected and dissolved or dispersed in a solvent or dispersant that does not dissolve or significantly swell the fibers constituting the nonwoven fabric, and this solution is impregnated into the nonwoven fabric. The order of impregnating the solution or dispersion of the binder resin into the nonwoven fabric is as follows: (1) impregnate the fiber-entangled nonwoven fabric before the shrinkage treatment; (2) impregnate the fiber-entangled nonwoven fabric after the shrinkage treatment; The impregnation may be performed in any order of removing the sea component of the fiber constituting the combined nonwoven fabric and then impregnating. However, if a firm texture of elasticity and flexibility is desired, the binder may be arranged in the order of (2). Preferably, a resin is applied. Further, in the case of performing in the order of (3), it is preferable to impregnate a temporary fixing resin such as a water-soluble resin before impregnating the binder resin, since the ultrafine fibers are not fixed by the binder resin.

As a method of solidifying the binder resin from the binder resin solution or the dispersion liquid impregnated in the fiber entangled nonwoven fabric, a method of solidifying by heat treatment, a method of solidifying by hot water treatment, and a method of solidifying by treating in a salt aqueous solution There is a method of coagulation by treating in a non-solvent or a solvent-non-solvent mixture, but appropriate coagulation conditions may be adopted according to the characteristics of the binder resin.

The fiber entangled nonwoven fabric with or without the binder resin is treated with a solvent or a decomposer of the sea component of the ultrafine fiber-generating fiber to remove the sea component and transform into a microfiber bundle to form a fibrous base material. I do. When a solvent treatment for removing sea components is performed, the elastic polymer is often swollen by the solvent, and when the solvent is dried, a partial sticking occurs inside the microfine fiber bundle and in the fiber entangled portion. If such agglomeration does not occur, the elastic microfibers are partially agglutinated in the microfiber bundle A and in the fiber entangled portion by treatment or heat treatment with another suitable solvent or swelling agent. The agglutination treatment is to perform partial agglutination of the elastic microfine fibers and the inelastic microfine fibers inside the microfine fiber bundle A and agglutination of the microfine fiber bundles in the fiber entangled portion, and the elastic microfine fiber component is dissolved. Further, it is necessary to prevent the inelastic ultrafine fiber bundle B from being bound and integrated by infiltrating into the inelastic ultrafine fiber bundle B and resolidifying. When the inelastic ultrafine fiber bundle B is bound and integrated by the elastic fiber component, the fiber bundle becomes hard, the texture of the sheet becomes hard, and it becomes difficult to obtain the expected elasticity. When the sheet is partially adhered to the elastic ultrafine fibers or partially adhered to the inelastic ultrafine fibers and the elastic ultrafine fibers, the form stability of the sheet is improved, and the surface is raised to finish the suede-like leather-like sheet. The effect of preventing fluff from falling off is also improved.

Next, when the leather-like sheet of the present invention is to be subjected to a suede-like finish, at least one surface of the fibrous substrate is provided with a fiber raised surface mainly composed of ultrafine fibers. The method of forming the fiber nap can be performed by a conventionally known method such as buffing with a sandpaper, brushing of a needle cloth, or the like. The fibrous base having a fibrous nap formed on its surface is then dyed, but may be dyed by a usual method according to the material of the resin constituting the fibrous base. The dyed suede-like fibrous substrate is subjected to conventionally known finishing treatments such as kneading, softening and brushing to obtain a suede-like leather-like sheet product. The suede-finished leather-like sheet obtained in the present invention has excellent uniformity of nap fibers on the surface, is flexible and stretchable, and has a rich texture, and is used for clothing, shoes, interiors and the like. It is suitable for.

When a silver surface is to be formed on the surface of the leather-like sheet obtained by the present invention, another polymer is applied and a surface forming / coloring treatment or an embossing treatment is applied. The sheet is subjected to a softener treatment, a kneading treatment, a dyeing treatment, a flame retarding treatment, a water repellent / waterproofing treatment, a weather resistance / light stabilizing treatment as necessary.

[0041]

Next, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples. In the examples, parts and% relate to weight unless otherwise specified. The shrinkage of the drawn yarn, the area shrinkage of the nonwoven fabric, the elongation of the fiber, the apparent density of the sheet, the tensile strength and the elongation of the sheet were measured by the following methods.

[Method of Measuring Shrinkage of Stretched Yarn]
With a load of 0.0025 g applied per decitex, marks are made at 10 cm intervals in the length direction. It is left for 20 seconds in a state of applying a load of 0.005 g per decitex in warm water at a temperature for shrinking. Mark spacing C after shrinkage
(Cm) is measured by applying a load of 0.0025 g per decitex. Drawing yarn shrinkage (%) = (10−C) / 10 × 100 [Measurement method of area shrinkage of non-woven fabric] The length and width of the non-woven fabric before shrinkage, and the length of the non-woven fabric after leaving for 1 minute in the desired warm water Measure the length and width of the nonwoven. Area shrinkage rate (%) of nonwoven fabric = (length before shrinkage × width before shrinkage−height after shrinkage × width after shrinkage) / (length before shrinkage × width before shrinkage) × 100

[Elongation of fiber] A sample was cut into 90 cm, the chucks of the tensile tester were set at 10 cm, and the sample was pinched. The tensile speed was 100 mm / min, and the chart speed was 100 mm /.
The breaking elongation at a speed of minutes was measured. [Apparent density of sheet] The apparent density is obtained by dividing the weight per unit area (g / cm2) of the artificial leather body by the thickness (cm). The thickness is measured according to JIS L1096.

[Tensile strength / tensile elongation of sheet] length 16c
A test piece of mx 2.5 cm in width was set between chucks of a tensile testing machine at 5 cm, and the breaking strength and elongation at a tensile speed of 25 mm / min and a chart speed of 50 mm / min were measured.

Example 1 Using a multi-core / sheath 37-island spinning apparatus, a polyester polyurethane chip was inserted into the core component side extruder (a), and a 6,12 nylon chip was inserted into the sheath component side extruder (b). A mixture of 1: 1 and polyethylene chips was melt-spun at a discharge ratio of extruder (a): extruder (b) = 50: 50 to obtain a 10 dtex raw yarn. When observing the cross section of this yarn, the sheath component is in a state where the island component 6,12 nylon is dispersed in about 500 islands in the polyethylene sea component, and the core component is uniformly dispersed in the sheath component. Was in a state of being. Next, the composite fiber was placed in a warm bath at 60 ° C.
The fiber was stretched 5 times, crimped, and cut to a fiber length of 51 mm to obtain a staple fiber of a microfiber-generating fiber a having a fineness of 4 dtex. The shrinkage in hot water at 95 ° C. of the drawn yarn obtained after drawing at the time of producing the staple fiber was 30%, and the elongation after shrinkage was 93%. On the other hand, in the spinning,
The polyester-polyurethane chips on the core component side are stopped, and only the sheath component-side extruder (b) is mixed with a 6,12 nylon chip and a polyethylene chip at a ratio of 1: 1 and melt-spun to obtain a 5 dtex raw yarn. I got The stretched yarn obtained by stretching the original yarn under the same conditions as above had a shrinkage in hot water of 95 ° C. of 30%, and the inelastic island component had high shrinkage performance.

Further, melt spinning was performed using a mixture of 6 nylon chips and polyethylene chips in a ratio of 1: 1.
A raw fiber of 0 decitex was obtained. Observation of the cross section of this yarn shows that the island component 6 nylon is approximately 6 in the polyethylene sea component.
It was in a state of being dispersed in 00 islands. Next, the conjugate fiber was stretched 2.5 times in a hot bath at 85 ° C., crimped, and cut into a fiber length of 51 mm to obtain a staple fiber of an ultrafine fiber generating fiber b having a fineness of 4 dtex. The shrinkage in hot water at 95 ° C. of the drawn yarn collected after drawing at the time of producing the staple fiber was 1%, and the elongation after shrinkage was 62%.

Then, the staple fibers of the microfiber-generating fiber a and the microfiber-generating fiber b are mixed at a ratio of 1: 1 to prepare a web with a cross wrap weber, and needle punching is performed alternately from both sides of the web at a total of 2,000 punches / cm 2. To produce a fiber-entangled nonwoven fabric having a basis weight of about 780 g / m2. This fiber entangled nonwoven fabric was shrunk by hot water of 95 ° C. by 25% in area. The shrink-treated fiber entangled nonwoven fabric was dried, and polyethylene in the fiber entangled nonwoven fabric was removed with hot toluene. By this polyethylene removal treatment, fusion between the polyester-based polyurethane and the 6,12 nylon ultra-fine fibers in the ultra-fine fiber bundle A and gluing to the portion where the 6-nylon ultra-fine fibers and the polyester polyurethane ultra-fine fibers in the ultra-fine fiber bundle B are in contact. To form a bonding point, thickness 1.8mm,
A fibrous substrate having a weight of 650 g / m2 and an apparent specific gravity of 0.36 g / cm3 was obtained.

The thickness of the fibrous substrate was sliced into two parts, the sliced surface was buffed with sandpaper to adjust the thickness to 0.6 mm, and the other surface was subjected to grain size # 4.
A brush raising treatment was performed with a sandpaper No. 00 to obtain a fiber raised sheet. This sheet was dyed brown with a 1: 2 type gold-containing complex dye, dried, rubbed, and subjected to a hair styling treatment.
As shown in Fig. 7, a soft brown suede-like artificial leather having a uniform surface and excellent elasticity was obtained. Observation of this artificial leather with a microscope revealed that the three-dimensional entangled structure formed by the ultrafine fiber bundle B was more relaxed than the three-dimensional entangled structure formed by the ultrafine fiber bundle A. In the table, ◎ indicates a texture that felt super soft, ○ indicates a texture that felt soft, and X indicates a texture that felt hard. In addition, ○ in the sense of fulfillment indicates that there is no feeling of breakage, and X indicates a paper-like feeling.

[0049]

[Table 1]

Example 2 Using a multi-core / sheath 37-island spinning apparatus, a polyester-based polyurethane chip was used for the core-component-side extruder (P), and a polyethylene-terephthalate chip and polyethylene were used for the sheath-component-side extruder (Q). Of 1: 1 mixed chips
Extruder (P): Extruder (Q) = 50: 50
Was melt-spun to obtain an original yarn of 10 dtex. Observing the cross section of this yarn, the sheath component was found to contain approximately 800 island island polyethylene terephthalate in the polyethylene sea component.
The core component was in a state of being dispersed in the island component, and the core component was in a state of being uniformly dispersed in the sheath component. Next, this conjugate fiber was stretched 3.0 times at 60 ° C., crimped, and cut into a fiber length of 51 mm to obtain a staple fiber of a microfiber-generating fiber a having a fineness of 3.4 dtex. The contraction rate of the drawn yarn collected after drawing at the time of producing the staple fiber in hot water at 95 ° C. is 5
It was 0% and the elongation after shrinkage was 106%. On the other hand, in the spinning, the polyester-based polyurethane chips in the core component side extruder (P) are stopped, and the polyethylene terephthalate chips and the polyethylene chips are mixed 1: 1 only in the sheath component side extruder (Q). Melt spinning was performed to obtain an original yarn of 5 dtex. The contraction rate of the drawn yarn obtained by drawing the raw yarn under the same conditions as above in hot water at 95 ° C. is 50%.
And the island component of the inelastic body had high shrinkage performance.

Further, melt spinning was performed using a mixture of polyethylene terephthalate chips and polyethylene chips in a ratio of 1: 1 to obtain a 10 denier raw yarn. Observation of the cross section of the original yarn showed that the island component polyethylene terephthalate was dispersed in about 800 islands in the polyethylene sea component. Next, the conjugate fiber was stretched 3.0 times at 95 ° C., crimped, and cut into a fiber length of 51 mm to obtain a staple fiber of an ultrafine fiber generating fiber b of 3.4 dtex. The shrinkage in hot water at 95 ° C. of the drawn yarn collected after drawing at the time of producing the staple fiber was 5%, and the elongation after shrinkage was 54%.

Next, the staple fibers of the microfiber-generating fiber a and the microfiber-generating fiber b are mixed at a ratio of 1: 1 to prepare a web with a cross wrap weber, and needle punching of 2000 punches / cm 2 is alternately performed from both sides of the web. To obtain a fiber-entangled nonwoven fabric having a basis weight of about 570 g / m2. This fiber entangled nonwoven fabric was shrunk by 95% of hot water by 45% in area. The shrink-treated fiber entangled nonwoven fabric was dried, and polyethylene in the fiber entangled nonwoven fabric was removed with hot toluene. By this polyethylene removal treatment, fusion between the polyester-based polyurethane and the polyethylene terephthalate ultra-fine fibers in the ultra-fine fiber bundle A and adhesion by gluing to the portion where the polyethylene terephthalate ultra-fine fibers and the polyester polyurethane ultra-fine fibers in the ultra-fine fiber bundle B are in contact. Dots were formed to obtain a fibrous base material having a thickness of 1.8 mm, a weight of 650 g / m2, and an apparent specific gravity of 0.36 g / cm3.

The thickness of the fibrous substrate was sliced into two parts, the sliced surface was buffed with sandpaper to adjust the thickness to 0.6 mm, and the other surface was subjected to grain size # 4.
A brush raising treatment was performed with a sandpaper No. 00 to obtain a fiber raised sheet. This sheet was dyed brown with a disperse dye, dried, rubbed, and subjected to a hair treatment to obtain a soft brown suede-like artificial leather having a uniform surface and excellent elasticity as shown in Table 1. . Observation of this artificial leather with a microscope revealed that the three-dimensional entangled structure formed by the ultrafine fiber bundle B was more relaxed than the three-dimensional entangled structure formed by the ultrafine fiber bundle A.

Comparative Example 1 Using a multi-core / sheath 37-island spinning apparatus, a polyester-based polyurethane chip was used for the core-component-side extruder (P) and a 6-nylon chip was used for the sheath-component-side extruder (Q). A mixture of polyethylene chips in a ratio of 1: 1 was melt-spun at a discharge rate of extruder (P): extruder (Q) = 50: 50 to obtain an original yarn of 10 dtex. Observing the cross section of this yarn, the sheath component is in a state where the island component 6-nylon is dispersed in about 300 islands in the polyethylene sea component,
The core component was in a state of being uniformly dispersed in the sheath component. Next, the conjugate fiber was stretched 2.5 times, crimped, and cut into a fiber length of 51 mm to obtain a staple fiber of a microfiber-generating fiber a having a fineness of 4 dtex. The shrinkage in hot water at 95 ° C. of the drawn yarn collected after drawing at the time of producing the staple fiber was 3%, and the elongation after shrinkage was 61%.

Further, melt spinning was performed using a mixture of 6-nylon chips and polyethylene chips at a ratio of 1: 1 to obtain a 10 dtex raw yarn. Observation of a cross-sectional photograph of the original yarn revealed that about 600 islands of the island component 6-nylon were dispersed in the polyethylene sea component. Next, the conjugate fiber is stretched 2.5 times, crimped, and the fiber length 5
The resultant was cut into 1 mm to obtain staples of ultrafine fiber generating fibers b having a fineness of 4 dtex. The shrinkage in hot water at 95 ° C. of the drawn yarn collected after drawing at the time of staple preparation was 2%, and the elongation after shrinkage was 63%.

Then, the staple fibers of the microfiber-generating fiber a and the microfiber-generating fiber b are mixed at a ratio of 1: 1 to prepare a web with a cross wrap weber, and needle punching is performed alternately from both sides of the web at a total of 2,000 punches / cm 2. To produce a fiber entangled nonwoven fabric having a basis weight of about 1000 g / m2. This fiber entangled nonwoven fabric was shrunk by 4% in area with hot water of 95 ° C. The shrink-treated fiber entangled nonwoven fabric was dried, and polyethylene in the fiber entangled nonwoven fabric was removed with hot toluene. By this polyethylene removal treatment, fusion between the polyester-based polyurethane and the 6-nylon ultrafine fiber in the ultrafine fiber bundle A and adhesion at the portion where the 6-nylon ultrafine fiber and the polyester polyurethane ultrafine fiber in the ultrafine fiber bundle B are in contact. Thus, a fibrous base material having a thickness of 2.0 mm, a weight of 650 g / m 2 and an apparent specific gravity of 0.33 g / cm 3 was obtained.

The thickness of the fibrous substrate was sliced into two parts, the sliced surface was buffed with sandpaper to adjust the thickness to 0.6 mm, and the other surface was subjected to grain size # 4.
A brush raising treatment was performed with a sandpaper No. 00 to obtain a fiber raised sheet. This sheet was dyed brown with a 1: 2 type gold-containing complex dye, dried, rubbed, and treated with a hair treatment. As shown in Table 1, the texture was soft but poor in elasticity and poor in appearance. Leather was obtained. When this artificial leather was observed with a microscope, no difference was observed in the state of relaxation between the three-dimensional entangled structure formed by the ultrafine fiber bundle A and the three-dimensional entangled structure formed by the ultrafine fiber bundle B.

Comparative Example 2 Using a multi-core / sheath 37-island spinning apparatus, a polyester polyurethane chip was inserted into the core-side extruder (P), and 6,12-nylon was injected into the sheath-side extruder (Q). A mixture of chips and polyethylene chips in a ratio of 1: 1 was melt-spun with an extruder (P): extruder (Q) = 25: 75 to obtain a 10 dtex raw yarn. Observing the cross section of this yarn, the sheath component is in a state where the island component 6,12-nylon is dispersed in about 500 islands in the polyethylene sea component, and the core component is uniformly dispersed in the sheath component. I was in a state. Next, the conjugate fiber was stretched 2.5 times, crimped, and cut into a fiber length of 51 mm to obtain a staple fiber of a microfiber-generating fiber a having a fineness of 4 dtex.
95 of the drawn yarn collected after drawing during staple fiber production
The shrinkage in hot water at 20 ° C. was 20%, and the elongation after shrinkage was 87%.

Next, using a staple fiber of the microfiber-generating fiber a, a web was produced with a cross lap weber, and a total of 2,000 punches / cm was alternately formed from both sides of the web.
Needle punching of 2 is performed, and the basis weight is about 680 g / m2
Fiber entangled nonwoven fabric. 9
The area was shrunk by hot water of 5 ° C. by 35%. The shrink-treated fiber entangled nonwoven fabric was dried, and polyethylene in the fiber entangled nonwoven fabric was removed with hot toluene. By this polyethylene removal treatment, an adhesion point was formed by fusion between the polyester-based polyurethane and the 6,12-nylon ultrafine fibers in the ultrafine fiber bundle A. The thickness was 1.2 mm, the weight was 650 g / m2, and the apparent specific gravity was 0.54 g. / Cm3 was obtained.

The thickness of the fibrous base material is sliced into two parts, the sliced surface is buffed with sandpaper to adjust the thickness to 0.6 mm, and the other surface is subjected to grain size # 4.
A brush raising treatment was performed with a sandpaper No. 00 to obtain a fiber raised sheet. This sheet was dyed brown with a 1: 2 type gold-containing complex dye, dried, rubbed, and subjected to a hair styling treatment.
As shown in Fig. 7, although the surface was uniform, the apparent specific gravity was high, giving a paper-like texture, and a suede-like artificial leather having low elasticity was obtained.

[0061]

The leather-like sheet of the present invention has a low elongation stress in the elongation range where structural elongation change does not substantially occur, has elasticity, has a soft texture and is excellent in a sense of fulfillment. For shoes, shoes, bags, various gloves, etc.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yoshihiro Tanba 1621 Sazu, Kurashiki-shi, Okayama F-term (reference) 4F055 AA02 BA02 DA07 EA03 EA04 EA05 EA09 EA12 EA14 EA15 EA16 EA24 EA38 HA04 HA14

Claims (2)

[Claims] 1. A nonwoven fabric in which an ultrafine fiber bundle A in which ultrafine fibers made of an elastic polymer are dispersed in an ultrafine fiber bundle made of an inelastic polymer and an ultrafine fiber bundle B made of an inelastic polymer are three-dimensionally entangled. A leather-like sheet, characterized in that the three-dimensional entangled structure formed by the ultrafine fiber bundle B is more relaxed than the three-dimensional entangled structure formed by the ultrafine fiber bundle A. 2. The following steps (1) to (4): (1) Highly shrinkable ultrafine fibers in which an island component made of an elastic polymer is dispersed in a dispersion medium component containing an island component made of an inelastic polymer and having a contracting ability. A step of preparing an entangled non-woven fabric using the low-shrinkage ultrafine fiber-generating fiber b having an island component composed of the generating fiber a and an inelastic polymer, (2) a step of shrinking the entangled non-woven fabric, and (3) A method for producing a leather-like sheet, comprising sequentially performing the steps of transforming the ultrafine fiber-generating fibers a and b into ultrafine fiber bundles and (4) finishing the surface like leather.