JP2014065979A - Leather-like sheet and method of producing leather-like sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a leather-like sheet having excellent flexibility, surface appearance, and sense of fulfillment similar to those of natural leather.SOLUTION: A leather-like sheet includes a fiber entangled body composed of fibers having an average single fiber fineness of 0.001-10 dtex and a polymer elastomer contained therein. The fiber entangled body has at least one of an ultrafine fiber bundle and a hollow fiber. The polymer elastomer is obtained by solidifying a urethane resin composition comprising a water soluble polyoxyalkylene-based compound, an organic acid ammonium salt or an inorganic acid ammonium salt and a self-emulsifiable aqueous polyurethane resin which is self-emulsified with an anionic group. An average distance between an outer fiber of the ultrafine fiber bundle or the hollow fiber and the polymer elastomer is 1 μm or greater.

Description

  The present invention relates to a leather-like sheet comprising a fiber entangled body and a polymer elastic body contained therein, and a method for producing the same, and in particular, a leather-like sheet having excellent flexibility, surface appearance and mechanical properties, and a method for producing the same. About.

Leather-like sheets, typified by artificial leather, are widely used in clothing, general materials, and sports products because they are lighter and easier to handle than natural leather. Artificial leather that has been widely used conventionally is manufactured, for example, as follows.
First, sea-island type composite fibers composed of two types of polymers with different solvent solubility are stapled (short fibers), and then converted into a web using a card, a cross wrapper, a random weber, etc., and needle punch, etc. The fibers are entangled with each other to obtain a nonwoven fabric. Next, the obtained nonwoven fabric is impregnated with a polymer elastic body such as polyurethane. Then, one of the polymers is dissolved and removed from the sea-island type composite fiber, so that only the fiber made of the other polymer is left to be made extremely fine. In this way, an artificial leather containing a nonwoven fabric composed of ultrafine fibers of short fibers and a polymer elastic body is obtained. It is widely recognized in various product markets that products using an artificial leather material obtained by this method can obtain an excellent texture due to the texture and appearance peculiar to ultrafine fibers.

  On the other hand, in recent years, there has been a demand for a solvent-free manufacturing process for the use of organic solvents because of the concern of adverse effects on human bodies and the environment. For example, a fiber using a water-soluble polymer component as an extraction component of an ultrafine fiber generating fiber or a hollow fiber generating fiber has been studied. Moreover, in the artificial leather manufacturing method, a water-based polymer elastic body has been studied as a resin impregnated inside the three-dimensional entangled nonwoven fabric.

  However, a substrate for artificial leather produced by a conventional solvent-free process has not been obtained with a hard texture and satisfactory appearance. In particular, the entangled nonwoven fabric is crushed in the thickness direction by external force such as tension or compression when making the multicomponent fiber ultrafine or hollow, and further stretched in the longitudinal direction by the tension of the treatment process, There is a problem that the ultrafine fibers or the ultrafine fibers and the polymer elastic body adhere to each other and the texture is cured. Therefore, various methods have been proposed so far in order to obtain a flexible texture and a high-quality appearance.

For example, a method of adding PVA to an aqueous emulsion such as polyurethane in order to increase the flexibility of artificial leather by releasing the emulsion and fibers when impregnating the aqueous emulsion into a nonwoven fabric is known (for example, Patent Documents). 1).
Conventionally, there is a method of using an impregnating solution for impregnating a base material or a compound having water repellency for the pretreatment. Specifically, there are known a method of impregnating a nonwoven fabric substrate before impregnation with a water repellent and then impregnating with an aqueous polyurethane, or a method of impregnating a substrate with an aqueous polyurethane liquid to which a water repellent compound is added. A method for introducing a water-repellent group into an aqueous polyurethane skeleton is also known (see, for example, Patent Documents 2 to 5).
Furthermore, a method of reducing the frictional force by containing inorganic particles in an aqueous polyurethane liquid having heat-sensitive gelation (for example, Patent Document 6), and a method of adding a foaming agent to an aqueous polyurethane liquid having heat-sensitive gelation (for example, Patent Document 7), and a method of adding a plasticizer to an aqueous polyurethane liquid having heat-sensitive gelling properties (for example, Patent Document 8).

Japanese Examined Patent Publication No. 6-55999 Japanese Patent No. 4025425 Japanese Patent No. 4788551 JP 2008-174868 A JP 2009-52165 A JP 2011-214210 A JP 2011-6834 A

However, the method disclosed in Patent Document 1 is a method of impregnating ultrafine fibers with a mixture of aqueous polyurethane and PVA, and a large amount of PVA is mixed in order to prevent adhesion between fibers or between fibers and aqueous polyurethane. There is a problem that the viscosity of the impregnating liquid becomes high and the workability of the impregnation step is lowered.
In addition, the methods disclosed in Patent Documents 2 to 5 make it difficult to uniformly impregnate the base material with the polymer elastic body due to the properties of the water repellent, and the film-forming property of the aqueous polyurethane may be lowered. . Thereby, the entangled nonwoven fabric is crushed in the thickness direction and further stretched in the vertical direction by the tension of the treatment process, and the physical properties and appearance of the leather-like sheet are not sufficient.
Furthermore, the methods disclosed in Patent Documents 6 and 7 cannot prevent adhesion between fibers or fibers and aqueous polyurethane, and there is a problem that the effect of improving the texture and appearance is not sufficient. Further, the method disclosed in Patent Document 8 is that the aqueous polyurethane is more easily crushed in the thickness direction by an external force such as tension or compression when the multicomponent fiber is turned into an ultrafine fiber or hollowed, and the fibers or Adhesion between fibers and aqueous polyurethane cannot be prevented, and there is a problem that the effect of improving the texture and appearance is not sufficient.

  That is, in the thickness range of 0.3 to 3.0 mm that is generally used in each field of artificial leather, there is a demand for flexible products that are lighter and have excellent mechanical properties. The above-described solventless production method cannot produce artificial leather that satisfies these requirements.

  The present invention has been made in view of the above problems, and can be manufactured by a method that does not require an organic solvent during the process, and is excellent in flexibility, surface appearance, mechanical properties, and natural leather. The aim is to obtain a similar leather-like sheet.

Therefore, as a result of intensive studies, the present inventors have made it possible to release a polymer elastic body and a fiber by using a urethane resin composition having a specific composition, even if it is a water-based elastic material. As a result, it was found that a leather-like sheet having excellent properties, surface appearance, and mechanical properties could be obtained.
That is, the present invention provides the following (1) to (9).
(1) A leather-like sheet comprising a fiber entangled body composed of fibers having an average single fiber fineness of 0.001 to 10 dtex, and a polymer elastic body contained therein, wherein the fiber entangled body is extremely fine A self-emulsifying aqueous solution having at least one of a fiber bundle and a hollow fiber, wherein the polymer elastic body is self-emulsified with a water-soluble polyoxyalkylene compound, an organic acid ammonium salt or an inorganic acid ammonium salt, and an anionic group A leather-like sheet obtained by solidifying a urethane resin composition containing a polyurethane resin, wherein an average distance between the outer peripheral fibers of the ultrafine fiber bundle or the hollow fibers and the polymer elastic body is 1 μm or more.
(2) The fiber entangled body is composed of an ultrafine fiber bundle or a hollow fiber, and the proportion of the outer peripheral portion of the ultrafine fiber bundle or hollow fiber having an average distance from the polymer elastic body of 1 μm or more is the ultrafine fiber bundle or hollow The leather-like sheet according to (1), which is 60% or more of the outer peripheral portion of the fiber.
(3) The self-emulsifying aqueous polyurethane resin according to (1) or (2), wherein 50% by mass or more of the polyol component is a polycarbonate-based polyol and 50% by mass or more of the diisocyanate component is hydrogenated MDI. Leather-like sheet.
(4) The leather-like sheet according to any one of (1) to (3), wherein the self-emulsifying water-based polyurethane resin has a storage elastic modulus of 10 to 500 MPa at 20 ° C. and 100 ° C. when solidified into a film. .
(5) The self-emulsifying aqueous polyurethane resin has a weight swelling rate of 8% or less in hot water treatment at 90 ° C. when solidified into a film, and a polymer obtained by solidifying the urethane resin composition into a film The elastic body is a leather-like sheet according to any one of the above (1) to (4), wherein the weight swelling ratio in hot water treatment at 90 ° C. is 50% or less.
(6) The leather-like sheet according to any one of (1) to (5), wherein the water-soluble polyoxyalkylene compound contains 60% by mass or more of polyoxyethylene units.
(7) The leather-like sheet according to any one of (1) to (6), further comprising a silver-tone resin layer having a thickness of 1 to 300 μm on the surface of the leather-like sheet.
(8) The leather-like sheet according to any one of the above (1) to (7), wherein the fibers present on the surface of the leather-like sheet are napped.
(9) A treatment for dissolving the water-soluble thermoplastic resin is performed on an entangled sheet including a composite fiber composed of a water-soluble thermoplastic resin and a water-insoluble thermoplastic resin, and the average single fiber fineness is 0. A step of forming a fiber entangled body having at least one of an ultrafine fiber bundle composed of fibers of 0.001 to 10 dtex and a hollow fiber, and impregnating and drying and solidifying a urethane resin composition in the fiber entangled body or entangled sheet The urethane resin composition comprises a water-soluble polyoxyalkylene compound, an organic acid ammonium salt or an inorganic acid ammonium salt, and a self-emulsifying aqueous polyurethane resin self-emulsified with an anionic group, A polymer elastic body obtained by solidifying a urethane resin composition and contained in the fiber entangled body, and an outer peripheral fiber of an ultrafine fiber bundle or Method for producing a leather-like sheet the average distance between the air-fiber is 1μm or more.

  The leather-like sheet of the present invention can be produced by a method that does not require an organic solvent during the process, and is excellent in flexibility, surface appearance, mechanical properties, and can be similar to natural leather. .

Hereinafter, embodiments of the present invention will be described in detail.
The leather-like sheet | seat which concerns on this invention is a leather-like sheet | seat which consists of a fiber entanglement body and the polymeric elastic body contained in the inside, Comprising: This fiber entanglement body has a microfiber bundle or a hollow fiber.

<Fiber entanglement>
The fiber entangled body is composed of fibers having an average single fiber fineness of 0.001 to 10 dtex, and the average single fiber fineness is preferably 0.01 to 5 dtex, particularly in the range of 0.02 to 0.3 dtex. It is preferable that In the fiber entangled body, when the average fineness is less than 0.001 dtex, the fibers are converged without being dissolved, and as a result, the flexibility and surface appearance of the obtained fiber bundle entangled body tend to be lowered. . Moreover, when larger than 10 dtex, there exists a tendency for a softness | flexibility and a surface appearance to be inferior.
The fiber entangled body has an ultrafine fiber bundle or a hollow fiber, whereby the leather-like sheet obtained can be excellent in flexibility, surface appearance, lightness, and the like. The ultrafine fiber bundle or hollow fiber is preferably made of long fibers. In addition, a long fiber is a fiber manufactured without passing through a cutting process like manufacturing a short fiber.

The resin constituting the fibers of the fiber entangled body is not particularly limited as long as it is a thermoplastic resin capable of forming fibers. Specifically, for example, aromatic polyesters such as polyethylene terephthalate (PET), isophthalic acid modified polyethylene terephthalate, dimethylisophthalic acid modified polyethylene terephthalate, sulfoisophthalic acid modified polyethylene terephthalate, polytrimethylene terephthalate polybutylene terephthalate, polyhexamethylene terephthalate An aliphatic polyester such as polylactic acid, polyethylene succinate, polybutylene succinate, polybutylene succinate adipate, polyhydroxybutyrate-polyhydroxyvalerate copolymer; polyamide 6, polyamide 66, polyamide 10, polyamide 11, polyamide 12, polyamides such as polyamide 6-12; polyethylene, polypropylene (PP), polybutene, Modified polyvinyl alcohol ethylene units containing 25 to 70 mole%; Rimechirupenten, polyolefins such as chlorinated polyolefin-polyurethane elastomer, polyamide elastomer, and thermoplastic elastomers such as polyester elastomers.
Among the above resins, modified PET such as PET and isophthalic acid modified PET, polylactic acid, polyamide 6, polyamide 12, polyamide 6-12, polypropylene and the like are preferable.

  In addition, it is preferable that a fiber entangled body consists of the fiber entangled body which has substantially single fineness spun | spun continuously, and there are few variations in fineness. In such a case, the strength of the fiber entangled body is high, and the surface appearance when dyed is preferable from the point of uniformity. In addition, the fiber entangled body having a substantially single fineness produced continuously means that the different types of nonwoven fabrics spun separately are not bonded together. When formed from a fiber entanglement obtained by entanglement of webs made of different fiber components with different fiber composition, ultrafine fiber fineness, fiber bundle fineness, fiber cross-sectional structure, etc., peel strength Tends to be insufficient.

The ultrafine fiber bundle or hollow fiber is formed by dissolving a water-soluble thermoplastic resin among composite fibers composed of a water-soluble thermoplastic resin and a water-insoluble thermoplastic resin.
Specifically, examples of the ultrafine fiber bundle include those obtained from sea-island type composite fibers using a water-soluble thermoplastic resin as a sea component. Examples of the hollow fiber include those obtained from a hollow composite fiber using a water-soluble thermoplastic resin as an island component. These sea-island type composite fibers or hollow type composite fibers are made into ultrafine fiber bundles or hollow fibers by dissolving a water-soluble thermoplastic resin in hot water.
The sea-island type composite fiber or the hollow type composite fiber is obtained by melt-spinning a water-soluble thermoplastic resin and a water-insoluble thermoplastic resin having low compatibility with the water-soluble thermoplastic resin and then combining them. The fineness of the sea-island composite fiber or the hollow composite fiber is preferably 0.5 to 15 dtex, and more preferably 0.5 to 3 dtex from the viewpoint of industrial properties.

The water-soluble thermoplastic resin is preferably a thermoplastic resin that can be dissolved and removed with water, an alkaline aqueous solution, an acidic aqueous solution, or the like and that can be melt-spun. Specific examples of such water-soluble thermoplastic resins include, for example, polyvinyl alcohol resins (PVA resins); modified polyesters containing polyethylene glycol and / or sulfonic acid alkali metal salts as copolymerization components; polyethylene oxide, etc. Is mentioned. Among these, PVA-based resins are particularly preferably used for the following reasons.
When a PVA-based resin is used as the water-soluble thermoplastic resin component of the composite fiber, the formed ultrafine fiber is greatly crimped. By this, the fiber bundle entanglement body with a high fiber density is obtained.
The water-insoluble thermoplastic resin and the water-soluble thermoplastic resin may contain various additives. Specific examples of the additive include, for example, a catalyst, an anti-coloring agent, a heat-resistant agent, a flame retardant, a lubricant, an antifouling agent, a fluorescent whitening agent, a matting agent, a coloring agent, a gloss improving agent, an antistatic agent, and an aromatic agent. , Deodorants, antibacterial agents, acaricides, inorganic fine particles and the like.

<Polymer elastic body>
In the present invention, the elastic polymer contained in the fiber entangled body is a water-soluble polyoxyalkylene compound, an organic acid ammonium salt or an inorganic acid ammonium salt, and a self-emulsifying aqueous polyurethane self-emulsified with an anionic group. A urethane resin composition containing a resin is solidified, and the average distance between the outer peripheral fibers or hollow fibers of the ultrafine fiber bundle and the polymer elastic body is 1 μm or more.
Here, the polymer elastic body is, for example, contained in the fiber entangled body by impregnating the fiber entangled body with a urethane resin composition further containing a diluent and then drying and solidifying the fiber entangled body. As the diluent, it is preferable to use a dispersed aqueous liquid in which a self-emulsifying aqueous polyurethane resin is dispersed.

When the average distance between the outer peripheral fibers or hollow fibers of the ultrafine fiber bundle and the polymer elastic body is less than 1 μm, the fibers are constrained by the polymer elastic body, so that the flexibility is lowered and the surface appearance is also reduced. Is inferior. Preferably, the average distance between the outer peripheral fiber or hollow fiber of the ultrafine fiber bundle and the polymer elastic body is 2 μm or more. The average distance is not particularly limited, but is preferably 20 μm or less, more preferably 10 μm or less.
The average distance between the ultrafine fiber bundle outer peripheral fiber or hollow fiber and the polymer elastic body is obtained by cutting the obtained leather-like sheet in the thickness direction and observing the cut surface using a scanning electron microscope (SEM). .

When the fiber-entangled body of the leather-like sheet is composed of ultrafine fiber bundles, the ratio of the outer peripheral portion of the ultrafine fiber bundle having an average distance from the polymer elastic body of 1 μm or more is 60% of the outer peripheral portion of the ultrafine fiber bundle. % Or more is preferable. Further, when the fiber-entangled body of the leather-like sheet is composed of hollow fibers, the ratio of the outer peripheral part of the hollow fiber whose average distance to the polymer elastic body is 1 μm or more is 60% or more of the outer peripheral part of the hollow fiber. It is preferable that
By setting the ratio of the outer periphery of the fiber 1 μm or more away from the polymer elastic body to 60% or more, the fiber is less likely to be restrained by the polymer elastic body, and the flexibility and surface appearance are improved. These proportions are preferably 80% or more, more preferably 95% or less.
The ratio of the average distance between the outer peripheral portion of the ultrafine fiber bundle or hollow fiber and the polymer elastic body is 1 μm or more. The obtained leather-like sheet is cut in the thickness direction and observed using a scanning electron microscope (SEM). Is required.

Further, the polymer elastic body contained in the leather-like sheet may have holes having an average pore diameter of 5 μm or less, and one or more holes may be present in a 10 μm square of the polymer elastic body. Since the self-emulsifying aqueous polyurethane resin of the present invention is harder than conventional polyurethane, it is preferable to have fine pores in terms of softening the obtained leather-like sheet. And by making the average pore diameter 5 μm or less, the film-forming property of polyurethane is improved, and the collapse in the thickness direction of the polymer elastic body and the leather-like sheet and the elongation in the vertical direction due to the processing process tension are suppressed. Thus, the flexibility and surface appearance of the obtained leather-like sheet can be improved. The polymer elastic body preferably has 5 or more holes having an average pore diameter of 3.0 μm or less. The number of holes is not particularly limited, but it is preferably 25 or less per 10 μm square.
Furthermore, it is better that the polymer elastic body does not have pores having a pore diameter larger than 10 μm, and even if it has, it is preferably 5% or less with respect to 0.2 to 10 μm pores. Thus, by having few holes exceeding 10 μm, the film-forming property of the polymer elastic body tends to be good, the porous structure is not easily crushed, and the leather-like sheet tends to have a soft texture.
The average pore diameter and the number of pores were determined by cutting the obtained leather-like sheet in the thickness direction, observing the cut surface with a scanning electron microscope (SEM), and measuring 10 μm square on the polymer elastic body existing on the cut surface. The arithmetic average value of the hole diameters of all the holes is calculated, and the number of holes of 0.2 to 10 μm is counted.
In the present invention, as described above, the urethane resin composition contains a water-soluble polyoxyalkylene compound and an organic acid ammonium salt or an inorganic acid ammonium salt, so that it is impregnated and solidified (for example, during heat-sensitive gelation). In addition, the polymer elastic body tends to have a porous structure. In addition, by using a self-emulsifying water-based polyurethane resin that is self-emulsified with a relatively hard anionic group, the porous structure is formed in each step such as a step of making a multicomponent fiber ultrafine or hollow. It becomes difficult to be crushed. For this reason, the porous structure is maintained even after various manufacturing processes, whereby a large number of pores having an average pore diameter of 5 μm or less can be formed in the polymer elastic body.

<Urethane resin composition>
Next, each component contained in the urethane resin composition will be described in detail.
[Self-emulsifying aqueous polyurethane resin]
A self-emulsifying aqueous polyurethane resin that is self-emulsified with an anionic group is relatively hard and has a low hot water swelling rate compared to other polyurethane resins. Therefore, the adhesion between the polymer elastic body and the fiber can be suppressed in the drying process of the urethane resin composition and the treatment process such as hot water treatment for making the multicomponent fiber ultrafine or hollow. Furthermore, the collapse in the thickness direction of the polymer elastic body and the leather-like sheet and the elongation in the vertical direction due to the treatment process tension can be suppressed. Therefore, the outer peripheral fiber or hollow fiber of the ultrafine fiber bundle is released from the polymer elastic body, and the average distance between the outer peripheral fiber or hollow fiber of the ultrafine fiber bundle and the polymer elastic body is easily set to 1 μm or more. It becomes easier to obtain leather-like sheets.

Moreover, in this invention, it is preferable that the storage elastic modulus in 20 degreeC and 100 degreeC at the time of film-forming and solidifying the said self-emulsification type | mold aqueous polyurethane resin is 10-500 Mpa.
In the ultrafine process or the hollowing process, the polymer elastic body, particularly the water-based polymer elastic body, has a problem that it easily swells with a treatment liquid such as water, hot water, or an alkaline solution and adheres to the fiber. By setting the storage elastic modulus at 20 ° C. and 100 ° C. to 10 MPa or more, in the treatment process such as hydrothermal treatment to make the fiber ultrafine or hollow, the adhesion between the polymer elastic body and the fiber is further suppressed. Further, it is easy to make the average distance between the above-mentioned fibers and the polymer elastic body 1 μm or more by suppressing the crushing in the thickness direction and the elongation in the vertical direction due to the treatment process tension. Furthermore, it becomes easy to form a porous structure.
Moreover, it becomes easy to form a polymer elastic body on a fiber by making the storage elastic modulus in 20 degreeC and 100 degreeC into 500 Mpa or less. Therefore, it is possible to prevent the polymer elastic body from falling off or the flexibility of the resulting leather-like sheet from being lowered in the process of hot water treatment or the like in which the multicomponent fiber is made ultrafine or hollow. The
In this invention, in order to acquire the said effect, it is preferable that it is a storage elastic modulus of 10-500 MPa in both 20 degreeC and 100 degreeC. From the above viewpoint, the storage elastic modulus at 20 ° C. and 100 ° C. is more preferably 20 to 300 MPa.
It is also preferable that the glass transition temperature found from the peak temperature of the loss elastic modulus of the polymer elastic body is 0 ° C. or less because the polymer elastic body can be easily formed into a film.
The storage elastic modulus at 20 ° C. and 100 ° C. of the self-emulsifying water-based polyurethane resin of the present invention is measured using a dynamic viscoelasticity measuring device by drying the aqueous liquid of the self-emulsifying water-based polyurethane resin to prepare a film sample. The storage elastic modulus was calculated. In addition, when using 2 types of self-emulsification type | mold water-based polyurethane resins, it prepares and measures a sample separately, respectively, and makes the sum multiplied by the mass ratio the value of the elasticity modulus of a self-emulsification type water-based polyurethane resin.

  The average particle size in the aqueous dispersion of the self-emulsifying water-based polyurethane resin is 0 because the film forming property of the polymer elastic body is good and the thickness reduction and elongation in the ultrafine fiber treatment and hollowing treatment are small. It is preferably 0.01 to 0.5 μm, more preferably 0.03 to 0.3 μm, and particularly preferably 0.05 to 0.2 μm. The average particle diameter is a value obtained by measuring an aqueous dispersion with a refractometer or the like.

  As a self-emulsifying aqueous polyurethane resin self-emulsified with an anionic group used in the present invention, a high-molecular polyol having an average molecular weight of 200 to 6000, an organic polyisocyanate, and a chain extender in a predetermined molar ratio. Various polyurethane-type resins obtained by making it react are mentioned.

Specific examples of the polymer polyol include, for example, polyether polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, poly (methyltetramethylene glycol) and copolymers thereof; polybutylene adipate diol, polybutylene sebacate Polyester polyols such as diol, polyhexamethylene adipate diol, poly (3-methyl-1,5-pentylene adipate) diol, poly (3-methyl-1,5-pentylene sebacate) diol, polycaprolactone diol, and the like The copolymer: linear polycarbonate polyol such as polyhexamethylene carbonate diol, polypentamethylene carbonate diol, polytetramethylene carbonate diol, (3-Methyl-1,5-pentylene carbonate) Polycarbonate polyol selected from branched polycarbonate polyol such as diol, alicyclic polycarbonate polyol such as polycyclohexane carbonate and copolymer thereof, and copolymer Polyester carbonate polyol etc. are mentioned. Moreover, you may use together polyfunctional alcohols, such as a trifunctional alcohol and a tetrafunctional alcohol, or short chain alcohols, such as ethylene glycol, as needed. These may be used alone or in combination of two or more.
In the present invention, in particular, a polycarbonate polyol such as a branched polycarbonate or an amorphous polycarbonate polyol obtained by copolymerizing a plurality of polycarbonates, an alicyclic polycarbonate polyol, or a linear polycarbonate polyol is a polymer polyol. It is preferable to contain 50 mass% or more. In addition, as a polyol copolymerized or mixed with a polycarbonate-based polyol, a polyether-based polyol is preferable because a leather-like sheet excellent in balance between flexibility and fullness can be obtained.

Specific examples of the organic polyisocyanate include, for example, non-yellowing diisocyanates such as aliphatic or alicyclic diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, and 4,4′-dicyclohexylmethane diisocyanate; 2,4-tri Examples thereof include aromatic diisocyanates such as range isocyanate, 2,6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, and xylylene diisocyanate polyurethane. Moreover, you may use together polyfunctional isocyanates, such as trifunctional isocyanate and tetrafunctional isocyanate, as needed. These may be used alone or in combination of two or more.
In the present invention, 4,4′-dicyclohexylmethane diisocyanate (hereinafter abbreviated as hydrogenated MDI) is preferably contained in an amount of 50% by mass or more of diisocyanate. When 50% by mass or more of hydrogenated MDI is contained, the polymer elastic body has excellent mechanical properties, and drops or swells when the extracted component of the ultrafine fiber generating fiber or hollow fiber generating fiber is extracted and removed. In addition, the average distance between the outer peripheral fiber or hollow fiber of the ultrafine fiber bundle and the polymer elastic body tends to be 1 μm or more. Isophorone diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, and xylylene diisocyanate are also preferable because of excellent mechanical properties.

In particular, in the self-emulsifying aqueous polyurethane resin of the present invention, it is preferable that 50% by mass or more of the polyol component is a polycarbonate-based polyol and 50% by mass or more of the diisocyanate component is hydrogenated MDI. As a result, the self-emulsifying aqueous polyurethane resin of the present invention tends to be an aqueous polyurethane having a storage elastic modulus of 10 to 500 MPa at 20 ° C. and 100 ° C. at the time of film formation, and the mechanical properties of the polymer elastic body are excellent. It will be a thing. Further, when extracting and removing components to be extracted from the ultrafine fiber generating fiber or hollow fiber generating fiber, the polymer elastic body is less likely to drop off and swell, and the average of the above-described fibers and the polymer elastic body. The distance is easily set to 1 μm or more, and the porous structure is easily maintained.
From the above viewpoint, in the self-emulsifying aqueous polyurethane resin, the polycarbonate polyol is more preferably 80% by mass or more of the polyol component, and the hydrogenated MDI is more preferably 80% by mass or more of the diisocyanate component. .

  Specific examples of the chain extender include, for example, diamines such as hydrazine, ethylenediamine, propylenediamine, hexamethylenediamine, nonamethylenediamine, xylylenediamine, isophoronediamine, piperazine and derivatives thereof, adipic acid dihydrazide, and isophthalic acid dihydrazide; Triamines such as diethylenetriamine; tetramines such as triethylenetetramine; ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-bis (β-hydroxyethoxy) benzene, 1,4 -Diols such as cyclohexanediol; Triols such as trimethylolpropane; Pentaols such as pentaerythritol; Aminoethyl alcohol, Aminopropyl alcohol Which amino alcohols and the like. These may be used alone or in combination of two or more. Among these, hydrazine, piperazine, ethylenediamine, hexamethylenediamine, isophoronediamine and derivatives thereof, and triamines such as diethylenetriamine are used in combination from the viewpoint of mechanical properties and 90 ° C hot water swelling. preferable. In addition, during the chain extension reaction, together with the chain extender, monoamines such as ethylamine, propylamine, and butylamine; carboxyl group-containing monoamine compounds such as 4-aminobutanoic acid and 6-aminohexanoic acid; methanol, ethanol, propanol, butanol, etc. Monools may be used in combination.

The self-emulsifying aqueous polyurethane resin used in the present invention is self-emulsified with an anionic group by containing a carboxyl group, a sulfonic acid group, a sulfamic acid group, two or more selected from these, or a salt thereof. It is preferable. Introducing an anionic group into a self-emulsifying aqueous polyurethane resin includes, for example, a compound having a carboxyl group and having two or more active hydrogens, a compound having a sulfonic acid group and having two or more active hydrogens, sulfamic acid A compound having a group and having two or more active hydrogens or a salt of a compound selected from these is used.
More specifically, examples of the compound having a carboxyl group and having two or more active hydrogens include 2,2-bis (hydroxymethyl) propionic acid, 2,2-bis (hydroxymethyl) butanoic acid, 2, Examples include a method of introducing an anionic group such as a carboxyl group into a polyurethane skeleton using a carboxyl group-containing diol such as 2-bis (hydroxymethyl) heptanoic acid or 2,2-bis (hydroxymethyl) octanoic acid. It is done. Also, sulfonic acid diols such as 3- (2,3-hydroxypropoxy) -1-propanesulfonic acid, or sulfamic acid diols such as N, N-bis (2-hydroxyalkyl) sulfamic acid and its alkyl ether adducts are used. An anionic group may be introduced as a compound having a sulfonic acid group or a sulfamic acid group and having two or more active hydrogens. Two or more of these may be used in combination. Among them, it is preferable to use a compound having a carboxyl group and having two or more active hydrogens in terms of mechanical properties and 90 ° C. hot water swelling.

Further, a salt of a compound having a carboxyl group and having two or more active hydrogens, a salt of a compound having a sulfonic acid group and having two or more active hydrogens, or two or more active hydrogens having a sulfamic acid group Examples of the salt of the compound having a salt include ammonium salts, amine salts, alkali metal salts, and combinations of two or more thereof.
Examples of the amine salt include salts of primary monoamines such as methylamine, ethylamine, propylamine and octylamine; salts of secondary monoamines such as dimethylamine, diethylamine and dibutylamine; trimethylamine, triethylamine, triethanolamine, N- Methyldiethanolamine, N.I. Examples of the alkali metal salt include salts of tertiary monoamines such as N-dimethylethanolamine, N-methylpiperidine, N-methylmorpholine, benzyldimethylamine, α-methylbenzyldimethylamine and N-dimethylaniline. And salts such as sodium, potassium and lithium.

Conventionally, as an aqueous polyurethane, a forced emulsification polyurethane emulsified with a surfactant such as a nonionic surfactant as an emulsifier, or a compound having a nonionic group such as a polyoxyethylene group is copolymerized with the polyurethane, and a nonionic group is obtained. Self-emulsifying type polyurethanes that self-emulsify with the use of the above are also known.
However, forced emulsification polyurethane has its film-forming property lowered or swelled in water due to the remaining emulsifier. Self-emulsifying polyurethane that self-emulsifies with nonionic groups is also easily swollen in water. Therefore, the polymer elastic bodies using these polyurethanes fall off in subsequent steps, for example, a drying step of the urethane resin composition, or a treatment step such as a hydrothermal treatment for making the multicomponent fiber ultrafine or hollow. It becomes easy to do. Furthermore, when these polyurethanes are used, the polymer elastic body and the leather-like sheet are crushed in the thickness direction or greatly stretched in the longitudinal direction by the treatment process tension, and the outer peripheral fibers or hollow fibers of the ultrafine fiber bundle and the polymer elasticity The body becomes difficult to release. Therefore, the above-mentioned forcedly emulsified polyurethane and aqueous polyurethane that self-emulsifies with a nonionic group are not suitable for the present invention.
In the self-emulsifying aqueous polyurethane resin self-emulsified with an anionic group used in the present invention, the content of polyalkylene glycol groups having 2 or less alkylene carbon atoms is preferably 1% by mass or less. Preferably it is 0.5 mass% or less. The self-emulsifying aqueous polyurethane resin of the present invention can improve the film-forming property of the aqueous polyurethane by self-emulsifying with an anionic group instead of an emulsifier or nonionic group.
Polyurethane containing a siloxane bond in the polymer skeleton is also known, but the polyurethane is easy to solidify while maintaining the state of aqueous polyurethane particles or secondary agglomerated particles, and the polyurethane is liable to have poor film-forming properties. . And in the process of hot water treatment or the like in which the multicomponent fiber is made into ultrafine fibers or hollowed out, the polymer elastic body easily falls off. Furthermore, the elongation in the vertical direction due to the crushing in the thickness direction or the processing process tension tends to increase. Therefore, the ratio of the siloxane bond contained in the self-emulsifying aqueous polyurethane resin skeleton is preferably 3% by mass or less, more preferably 1% by mass or less.

[Ammonium salt]
In the present invention, an organic acid ammonium salt or an inorganic acid ammonium salt is mixed with the urethane resin composition, whereby the polymer elastic body is obtained by solidifying the urethane resin composition heat-gelled with the ammonium salt. Become. Thus, when heat-sensitive gelled with an ammonium salt and solidified, the average distance between the outer peripheral fibers or hollow fibers of the ultrafine fiber bundle and the polymer elastic body tends to be 1 μm or more. In other words, even in a treatment process such as hydrothermal treatment in which multicomponent fibers are made into ultrafine fibers or hollowed out, swelling and adhesion of the polymer elastic body hardly occur, and the resulting leather-like sheet tends to have excellent flexibility and surface appearance. It becomes.
Moreover, the urethane resin composition of the present invention is easily solidified without maintaining the particle state (or secondary agglomerated state) of the self-emulsifying aqueous polyurethane resin by heat-sensitive gelation with an ammonium salt. In addition, it becomes difficult to form pores in the particle gap due to solidification while maintaining the particle state. Specifically, when the leather-like sheet is cut and observed with an electron microscope, it is preferably about 0.1 to 1 μm, more preferably about 0.2 to 0.5 μm of an aqueous polyurethane primary particle, or secondary. It is preferable that particles resulting from the aggregated particles are not observed, and it is more preferable that no particles are observed.
In addition, the organic acid ammonium salt or inorganic acid ammonium salt is formed by lowering the pH of the aqueous liquid by raising the temperature of the aqueous liquid from room temperature (23 ° C.) to about 40 to 100 ° C. It is preferable to reduce the property. Thereby, the migration described later can be suppressed.
Conventionally, a method for heat-sensitive gelation of an aqueous polyurethane emulsified with a surfactant such as a nonionic surfactant with an alkali metal salt or an alkaline earth metal salt by lowering the cloud point of the surfactant is known. Yes. However, this method tends to solidify the polyurethane in a state where the film-forming property of the polyurethane is lowered and the particle state (or secondary aggregation state) of the aqueous polyurethane resin is maintained. In addition, the aqueous polyurethane in the method tends to swell and falls off in a treatment process such as hot water treatment to make the multicomponent fiber into ultrafine fibers or hollow, and further, collapse in the thickness direction or treatment process The elongation in the longitudinal direction of the tension increases, and it becomes difficult to release the microfiber bundle outer peripheral fibers or hollow fibers and the polymer elastic body.
0.1-30 mass parts is preferable with respect to 100 mass parts (solid content) of self-emulsification type aqueous polyurethane resins, and, as for ammonium salt, it is still more preferable that it is 0.5-20 mass parts.

Examples of the inorganic acid in the ammonium salt of inorganic acid include perchloric acid, carbonic acid, sulfuric acid, persulfuric acid, sulfurous acid, phosphoric acid, and nitric acid. Specific ammonium salts of inorganic acids include ammonium persulfate, ammonium perchlorate, ammonium carbonate, ammonium sulfate, ammonium hydrogen sulfate, ammonium sulfite, ammonium hydrogen sulfite, ammonium hydrogen phosphate, ammonium dihydrogen phosphate, ammonium nitrate, and the like. It is done. Among these, ammonium sulfate, ammonium hydrogen phosphate, diphosphoric acid phosphate are excellent because they are safe to handle, have problems of volatilization during drying, are easy to remove after drying, and have excellent migration control effects. At least one selected from ammonium hydrogen is preferred.
Examples of the organic acid in the ammonium salt of organic acid include saturated fatty acids such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, capric acid, stearic acid; unsaturated fatty acids such as oleic acid and linoleic acid; benzoic acid, Aromatic carboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid; saturated dicarboxylic acids such as malic acid, citric acid, succinic acid, malonic acid, succinic acid and adipic acid; unsaturated carboxylic acids such as fumaric acid and maleic acid; lactic acid Acrylic acid, polyacrylic acid, polymaleic acid and the like. Among them, it is selected from carboxylic acids having 1 to 4 carbon atoms because of safety in handling, problems of volatilization during drying, ease of removal after drying, and excellent migration suppressing effect, and further, it tends to be a strong gel. At least one selected from the above is preferred.

[Water-soluble polyoxyalkylene compounds]
In the present invention, the water-soluble polyoxyalkylene compound is mixed with the urethane resin composition as described above. When a water-soluble polyalkylene compound is mixed with a urethane resin composition, the average distance between the outer peripheral fibers or hollow fibers of the ultrafine fiber bundle and the polymer elastic body is likely to be 1 μm or more, and the ratio of the average distance of 1 μm or more is 60%. %, And the resulting leather-like sheet tends to be excellent in flexibility and surface appearance. Although the detailed reason is unknown, the water-soluble polyoxyalkylene compound aggregates during the solidification process of the water-based polyurethane and moves to the surface of the polymer elastic body to prevent adhesion to the fiber. It is presumed that the effect of releasing from the fiber can be easily developed without impairing the properties, and thereby the above effect can be obtained.
In particular, when the polymer elastic body is a self-emulsifying aqueous polyurethane resin that is self-emulsified with an anionic group and is used in combination with an ammonium salt, the effect becomes remarkable. The effect of the aqueous polyurethane resin is more easily exhibited when the weight swelling ratio in a 90 ° C. hot water treatment described later is 8% or less and the storage elastic modulus at 20 ° C. and 100 ° C. is 10 to 500 MPa. When the water-soluble polyoxyalkylene compound is not mixed, the average distance between the outer peripheral fiber or hollow fiber of the ultrafine fiber bundle and the polymer elastic body tends to be larger than 1 μm, and the flexibility and the surface appearance are deteriorated.
Moreover, 0.5-50 mass parts is preferable with respect to 100 mass parts (solid content) of a self-emulsification type aqueous polyurethane resin, and, as for a water-soluble polyoxyalkylene type compound, it is still more preferable that it is 1-30 mass parts. By setting the upper limit value or less, it is prevented that the texture and surface appearance change with time due to bleeding, and there are also problems such as tackiness, stickiness and texture hardening due to the remaining of the compound. Less likely to occur. Moreover, it becomes easy to exhibit the effect of this compound by setting it as more than a lower limit.

The cloud point of the water-soluble polyoxyalkylene compound is preferably 60 ° C. or higher, and more preferably 70 ° C. or higher. In addition, the molecular weight of the water-soluble polyoxyalkylene compound is preferably 5,000 to 500,000, and more preferably 10,000 to 300,000 in terms of number average molecular weight because the effects of the present invention are easily obtained. Further, the water-soluble polyalkylene glycol compound is preferably in a solid state at 25 ° C., or 5000 mPa · sec or more, more preferably 10,000 mPa · sec or more. In the present invention, by using a water-soluble polyoxyalkylene compound having the above characteristics, the effects of the present invention can be easily obtained. For example, the flexibility, surface appearance, mechanical properties of a leather-like sheet of a polymer elastic body, and the like. The characteristics can be made excellent.
In addition, in this specification, the number average molecular weight was calculated | required by carrying out the gel permeation chromatography (GPC) measurement on the following conditions.
Column: Showa Denko Co., Ltd. "Shodex GPC KF-806M" and "Shodex GPC KF-802.5" connected in series in this order.
Solvent: Tetrahydrofuran Measurement temperature: 35 ° C
Detector: Differential refractive index (RI) detector Standard material: Polymethyl methacrylate

  In the present invention, the water-soluble polyoxyalkylene compound refers to a compound having at least one polyoxyalkylene unit. The water-soluble polyoxyalkylene compound is a nonionic compound, and since the effects of the present invention are more easily obtained, the polyoxyalkylene unit preferably contains 50% by mass or more of polyoxyalkylene units. It is more preferable to contain it by mass% or more. More specifically, it is preferable to contain 60% by mass or more of polyoxyethylene units, and more preferably 70% by mass or more of polyoxyethylene units. Moreover, it is preferable that an alkyl group unit is less than 40 mass%.

  Specific water-soluble polyoxyalkylene compounds include, for example, linear polyoxyalkylene glycols such as polyethylene glycol, polyoxypropylene glycol, and polyoxybutylene glycol, and random copolymers or block copolymers thereof; polyglycerin, Polyoxyalkylene glycerin such as polyoxyethylene glycerin, polyoxypropylene glyceryl ether, polyoxybutylene glyceryl ether and the random copolymer or block copolymer thereof; polyoxyethylene diglyceryl ether, polyoxypropylene diglyceryl ether, polyoxy Polyoxyalkylene diglyceryl ethers such as butylene diglyceryl ether and random or block copolymers thereof; polyoxyethylene Polyoxyalkylene trimethylolpropane, such as trimethylolpropane, polyoxypropylenetrimethylolpropane, polyoxybutylenetrimethylolpropane, and random or block copolymers thereof; polyoxyethylene pentaerythritol ether, polyoxypropylene pentaerythritol ether , Polyoxyalkylene pentaerythritol ethers such as polyoxybutylene pentaerythritol ether and random copolymers or block copolymers thereof; polyoxyalkylene sorbits such as polyoxyethylene sorbitol, polyoxypropylene sorbitol, polyoxybutylene sorbitol and random thereof Copolymer or block copolymer; polyoxyethylene methyl glucoside, poly Polyoxyglucosides such as oxypropylene methyl glucoside and polyoxybutylene methyl glucoside and random copolymers or block copolymers thereof; polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether Polyoxyethylene monoalkyl ether, polyoxypropylene butyl ether, polyoxypropylene myristyl ether, polyoxypropylene cetyl ether, polyoxypropylene stearyl ether, polyoxypropylene lanolin alcohol ether and other polyoxyalkylene alkyl ethers and their random copolymer Polymer or block copolymer; polyoxyethylene sorbitan ether, polyoxyp Polyoxysorbitan ethers such as lopyrene sorbitan ether and polyoxybutylene sorbitan ether and random copolymers or block copolymers thereof; polyoxyethylene hydrogenated castor oil, polyoxypropylene hydrogenated castor oil, polyoxybutylene hydrogenated castor oil, and other poly Oxyalkylene hydrogenated castor oil and its random copolymer or block copolymer, polyoxyethylene coconut oil alkylamine, polyoxyethylene oleylamine, polyoxyethylene stearylamine, polyoxyethylene coconut oil fatty acid monoethanolamide, polyoxyethylene coconut Polyoxyalkylene alkylamines such as oil fatty acid amide, polyoxyethylene coconut oil didiethanolamide, polyoxyethylene lauric acid monoethanolamide, Such as xylene alkylene alkyl amides. Moreover, as long as it contains 1 or more types of alkylene glycol, you may contain other groups, such as a hydroxyl group or the esterified product of a hydroxyl group. Moreover, although it is preferable to comprise only a nonionic group, you may contain an anion group and a cation group in part.

  On the other hand, as a method for releasing a polymer elastic body from a fiber, a method using a silicone compound is also known. However, the silicone compound tends to inhibit the film-forming property of the polyurethane, and makes it easy for the polyurethane to fall off in a treatment process such as hot water treatment in which the multicomponent fiber is made into ultrafine fibers or hollowed out. Furthermore, the polymer elastic body is crushed in the thickness direction, and the elongation in the vertical direction tends to increase with the treatment process tension. Therefore, the content of the silicone compound is preferably 3% by mass or less, more preferably 1% by mass or less of the leather-like sheet.

[Weight swelling ratio]
The self-emulsifying aqueous polyurethane resin of the present invention preferably has a weight swelling ratio of 8% or less in 90 ° C. hot water treatment when the film is solidified. Moreover, it is preferable that the film which consists of a polymeric elastic body obtained by film-forming and solidifying the said urethane resin composition has a weight swelling rate in a 90 degreeC hot-water process of 50% or less.
The self-emulsifying aqueous polyurethane resin of the present invention may swell with a treatment liquid such as water, hot water or an alkaline solution in the ultrafine process or hollow process, and may easily adhere to the fiber. By using a material having low water swellability, swelling adhesion between the polymer elastic body and the fibers can be suppressed in a treatment process such as hot water treatment in the ultrafine process or hollow process. Further, the polymer elastic body and the leather-like sheet can be prevented from being crushed in the thickness direction and stretched in the vertical direction due to the treatment process tension. Therefore, the outer peripheral fiber or hollow fiber of the ultrafine fiber bundle is released from the polymer elastic body, and a leather-like sheet having a soft texture can be obtained. And it becomes easy for the average distance of the outer periphery fiber or hollow fiber of a microfiber bundle, and a polymeric elastic body to be 1 micrometer or more. In addition, the porous structure of the polymer elastic body can be easily maintained.
The weight swelling rate when the self-emulsifying aqueous polyurethane resin is solidified into a film is more preferably 5% or less, and further preferably 0.1% to 5%.
The weight swelling ratio of the polymer elastic body obtained from the urethane resin composition is preferably 50% or less, and more preferably 2% to 30%.
In the present invention, organic acid ammonium salt or inorganic acid ammonium salt is mixed with water-based polyurethane self-emulsified with an anionic group, so that swelling property with water or hot water can be suppressed, and the urethane resin composition described above can be used. It becomes easy to obtain a weight swelling rate. Further, in the self-emulsifying water-based polyurethane resin, 50% by mass or more of the polyol component is polycarbonate polyol, 50% by mass or more of the diisocyanate component is hydrogenated MDI, and the storage elastic modulus at 20 ° C. and 100 ° C. is 10 By setting it to ˜500 MPa, the self-emulsifying water-based polyurethane resin self-emulsified with an anionic group has low swelling property with water or hot water, and the weight swelling rate is easily obtained.
In the present invention, the weight swelling ratio in the hot water treatment at 90 ° C. is that the film obtained by film-forming and solidifying the aqueous liquid of the self-emulsifying aqueous polyurethane resin or the urethane resin composition is heat-treated at 120 ° C. for 5 minutes, It is determined by measuring the weight swelling rate immediately after treatment with hot water at 90 ° C. for 60 minutes.

[Thickening polysaccharide]
The urethane resin composition preferably further contains a thickening polysaccharide.
By mixing the thickening polysaccharide with the urethane resin composition, it becomes easy to improve the releasability between the fiber and the polymer elastic body. This is because the urethane resin composition contains a thickening polysaccharide, so that the viscosity of the aqueous dispersion impregnated in the fiber entangled body is hardly lowered even when the temperature is increased by the heat-sensitive gelation treatment. It is presumed that the cause is that the contraction is suppressed.
The average distance between the outer peripheral fibers or hollow fibers of the ultrafine fiber bundle and the polymer elastic body tends to be 1 μm or more, and the average distance between the outer peripheral fibers or hollow fibers of the ultrafine fiber bundle and the polymer elastic body is 1 μm or more. The ratio tends to be 60% or more. Furthermore, one or more holes having an average pore diameter of 5 μm or less of the polymer elastic body are likely to be present in a 10 μm square of the polymer elastic body, and thereby the flexibility and surface appearance of the obtained leather-like sheet may be excellent. . In particular, the polymer elastic body contains a self-emulsifying aqueous polyurethane resin that is self-emulsified with an anionic group, and has a weight swelling ratio of not more than 8% at 90 ° C. hot water treatment, and storage elasticity at 20 ° C. and 100 ° C. The effect becomes significant when the rate is 10 to 500 MPa.
Moreover, it is preferable to mix | blend 0.1-10 mass parts with respect to 100 mass parts (solid content) of self-emulsification type water-based polyurethane resin, Furthermore, 0.2-5 mass parts is blended.
By setting it to these upper limit values or less, the compound bleeds with time, and the texture and surface appearance are prevented from changing with time. Also, the tackiness, stickiness and texture due to the remaining thickening polysaccharides are prevented. Problems such as curing are less likely to occur. Furthermore, the viscosity of the impregnating liquid can be set to an appropriate value. Moreover, it becomes easy to exhibit the effect of this compound by setting it as more than a lower limit.

Examples of thickening polysaccharides include cellulose derivatives such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl hydroxypropyl cellulose, and carboxymethyl cellulose; starch derivatives such as soluble starch, carboxymethyl starch, and methyl starch; sodium alginate , Alginic acid such as propylene glycol alginate; guar gum, carrageenan, galactan, gum arabic, locust bin gum, quince seed, tragacanth gum, pectin, mannan, starch, xanthan gum, dextran, succinoglucan, curdlan, hyaluronic acid and its salts, etc. Natural polysaccharides; natural proteins such as casein, gelatin, collagen, and albumin; polyoxyethylene methyl group Course (mono, di or tri) laurate, polyoxyethylene methyl glucose (mono, di or tri) myristate, polyoxyethylene methyl glucose (mono, di or tri) palmitate, polyoxyethylene methyl glucose (mono, di or tri) ) Stearate, polyoxyethylene methyl glucose (mono, di or tri) isostearate, polyoxyalkylene non-ionic polymers such as polyoxyethylene methyl glucose (mono, di or tri) oleate, and mixtures thereof It is done. Examples of commercially available products include HEC AX-15 (manufactured by Sumitomo Seika Chemicals Co., Ltd., hydroxyethyl cellulose), Kelzan (manufactured by Sanki Co., Ltd., polymer polysaccharide (xanthan gum)), and the like.
These thickening polysaccharides can be used alone or in combination of two or more.

The molecular weight of the thickening polysaccharide is preferably 1,000 to 500,000 and more preferably 5,000 to 200,000 in terms of number average molecular weight.
In addition, when the thickening polysaccharide is mixed, it is preferable to pass through a washing step after impregnating the urethane resin composition in order to suppress bleed of the thickening polysaccharide with time and generation of stickiness due to moisture absorption.

[Crosslinking agent]
The urethane resin composition may further contain a crosslinking agent containing two or more functional groups capable of reacting with the functional group of the monomer unit forming the polyurethane in the molecule. The polymer elastic body forms a cross-linked structure with a cross-linking agent, and its water absorption rate, adhesion to fibers and hardness are controlled. Examples of the crosslinking agent include carbodiimide compounds, epoxy compounds, oxazoline compounds, or self-crosslinking compounds such as polyisocyanate compounds and polyfunctional block isocyanate compounds.

[Polymer elastic material]
The urethane resin composition of the present invention includes a polymer elastic material such as rubber and thermoplastic elastomer other than the self-emulsifying water-based polyurethane resin that is self-emulsified with an anionic group in a category that does not impair the effects of the present invention. May be. Examples of such rubber and thermoplastic elastomer include diene rubber (butadiene rubber, isoprene rubber, chloroprene rubber, styrene-butadiene rubber, etc.), nitrile rubber (nitrile rubber, hydrogenated nitrile rubber, etc.), acrylic rubber, and the like. (Acrylic rubber, etc.), urethane rubber (polyether urethane rubber, polyester urethane rubber, etc.), silicone rubber, olefin rubber (ethylene-propylene rubber, etc.), fluorine rubber, polystyrene elastomer (styrene-butadiene block copolymer, styrene) -Isoprene block copolymer, styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, acrylonitrile-butadiene-styrene copolymer, acrylonitrile-styrene Polymers, hydrogenated products or epoxidized products thereof), polyolefin elastomers (such as copolymers of olefins and rubber components such as propylene-ethylene / propylene rubber copolymers, or hydrogenated products thereof), polyurethanes Elastomer (polyether urethane elastomer, polyester urethane elastomer, polyether ester urethane elastomer, polycarbonate urethane elastomer, polyether carbonate urethane elastomer, polyester carbonate urethane elastomer, etc.), polyester elastomer (polyether ester elastomer, polyester ester elastomer, etc.), polyamide Elastomers (such as polyester amide elastomers and polyether ester amide elastomers) ), Such as halogen-based elastomer (vinyl chloride-based elastomer) and the like. These may be used alone or in combination of two or more. Preferably, it is a self-emulsifying aqueous polyurethane resin in which 60% by mass or more, more preferably 80% by mass or more of the polymer elastic material is self-emulsified with an anionic group.

In the present invention, even if the urethane resin composition contains a rubber other than the self-emulsifying water-based polyurethane resin as a polymer elastic material, a physical property of the polymer elastic material is preferably not impaired, For example, the storage elastic modulus at 20 ° C. and 100 ° C. of the polymer elastic material is preferably 10 to 500 MPa, and more preferably 20 to 300 MPa. Further, the weight swelling ratio in the 90 ° C. hot water treatment of the polymer elastic material is preferably 8% or less, more preferably 5% or less, and further preferably 0.1% to 5%. .
In addition, since the measuring method of the storage elastic modulus and weight swelling rate of a polymeric elastic material is the same as that of a self-emulsifying polyurethane resin, a description thereof will be omitted.

  Urethane resin compositions include the above-mentioned thickening polysaccharides, water-soluble polyoxyalkylene compounds, ammonium salts, nonionic water-soluble compounds, nonionic surfactants, anionic surfactants, cationic surfactants, etc. May be mixed to adjust the solidified state of the polymer elastic body and the release state from the fiber entangled body.

  The urethane resin composition may contain various additives other than the various materials described above. Specific examples of additives include, for example, softeners, water repellents, catalysts, anti-coloring agents, heat-resistant agents, flame retardants, lubricants, antifouling agents, fluorescent whitening agents, matting agents, coloring agents, and gloss improvers. , Antistatic agents, fragrances, deodorants, antibacterial agents, acaricides, inorganic fine particles and the like.

<Surface treatment of leather-like sheet>
Various treatments may be applied to the surface of the leather-like sheet. For example, it is also preferable that a silver-tone resin layer is further provided on the surface of the leather-like sheet. The thickness of the silver tone resin layer is, for example, 1 to 300 μm. It is also preferred that the fibers present on the surface of the leather-like sheet are napped.

The apparent density of the leather-like sheet is not particularly limited, but a range of 0.2 to 0.8 g / cm ³ is excellent in balance between fullness and flexibility, and has mechanical properties and shape retention. From the point which is excellent in it. Moreover, the thickness of the leather-like sheet is not particularly limited, but is preferably in the range of about 0.3 to 4 mm from the viewpoint of obtaining a texture excellent in balance between fullness and flexibility.

  The ratio of the elastic polymer contained in the leather-like sheet is preferably in the range of 1 to 60 parts by mass, more preferably 5 to 40 parts by mass, with respect to 100 parts by mass of the fiber entangled body. 30 parts by mass is particularly preferable. In addition, by making the content rate of a polymeric elastic body below the said upper limit, there exists a tendency for a rubber feeling to become difficult to become strong and for a feeling to become favorable. Moreover, it becomes easy to make a softness | flexibility and surface appearance favorable by making elongation and thickness in a manufacturing process favorable by setting it as the said lower limit or more.

<Manufacturing method>
Next, an embodiment of the method for producing a leather-like sheet of the present invention will be described.
The leather-like sheet manufacturing method of the present embodiment includes, for example, a fiber sheet composed of a composite fiber such as a sea-island composite fiber or a hollow composite fiber, which is composed of a water-soluble thermoplastic resin and a water-insoluble thermoplastic resin. The fiber sheet manufacturing process (1) to be manufactured, the entanglement process (2) in which a plurality of fiber sheets are entangled and entangled, and the entangled sheet is subjected to wet heat shrinkage or hot water as necessary. A shrinking treatment step (3) for creating a shrinking web by shrinking, and a water-soluble thermoplastic resin of a composite fiber such as a sea-island composite fiber or a hollow composite fiber is dissolved in hot water, thereby producing an ultrafine fiber bundle. Or the fiber bundle entanglement formation process or hollow fiber entanglement formation process (4) which forms the fiber entanglement body of a hollow fiber is provided. In addition, the fiber entangled body is impregnated with a urethane resin composition and dried and solidified, and the polymer entangled body contains a polymer elastic body impregnation step (5) and a post-processing step (6) for performing surface treatment. Prepare. Hereinafter, each step will be described in detail.

(1) Fiber sheet manufacturing process As this process, a spunbond sheet comprising sea-island type composite fibers or hollow type composite fibers obtained by melt spinning a water-soluble thermoplastic resin and a water-insoluble thermoplastic resin is used as a fiber sheet. Manufacturing is mentioned as an example. Hereinafter, a method for forming the spunbond sheet will be described in detail.

  After the water-soluble thermoplastic resin and the water-insoluble thermoplastic resin are combined by melt spinning, a spunbond sheet made of composite fibers of long fibers is obtained by stretching and depositing by a spunbond method.

First, a water-soluble thermoplastic resin and a water-insoluble thermoplastic resin are melted and kneaded by separate extruders, and melted composite spinning that simultaneously discharges molten resin strands from different spinnerets, thereby using sea-island composite fibers or hollow molds. A composite fiber is formed. The mass ratio of the water-soluble thermoplastic resin to the water-insoluble thermoplastic resin is preferably 5/95 to 50/50, and more preferably 10/90 to 40/60. Is preferable from the viewpoint that a good fiber entangled body can be obtained and the fiber formability is excellent.
In the melt composite spinning, the number of islands in the composite fiber is preferably 4 to 4000 islands / fiber, and more preferably 10 to 1000 islands / fiber, the fiber entangled body having a small single fiber fineness and good physical properties. Is more preferable in that it is obtained.

After the composite fiber is cooled by a cooling device, it is drawn by a high-speed air stream at a speed corresponding to a take-up speed of 1000 to 6000 m / min so as to obtain a desired fineness using a suction device such as an air jet nozzle. Then, the spunbond sheet is formed by depositing the drawn conjugate fiber on the movable collection surface. At this time, the spunbond sheet may be partially crimped as necessary. The basis weight of the spunbond sheet is preferably in the range of ^{20 to} 500 g / m ^{2 from} the viewpoint of obtaining a homogeneous fiber bundle entangled body and excellent productivity.

(2) Entanglement process Next, (1) an intertwined sheet is formed by overlapping and intertwining a plurality of fiber sheets obtained in the fiber sheet manufacturing process. Hereinafter, an example of an entanglement process for forming an entangled sheet by overlapping a plurality of obtained spunbond sheets and intertwining them will be described.
The entangled sheet is formed by performing an entanglement treatment using a known nonwoven fabric manufacturing method such as needle punching or high-pressure water flow treatment.

First, a silicone oil agent or a mineral oil oil agent such as a needle breakage prevention oil agent, an antistatic oil agent or an entanglement improving oil agent is applied to the spunbond sheet. In order to reduce the basis weight unevenness, an oil agent may be applied after two or more spunbond sheets are overlapped with a cross wrapper.
After the oil agent is applied, for example, an entanglement process is performed in which the spunbond sheet is entangled three-dimensionally by a needle punch process. The needle condition is selected from the number of barbs of the needle needle and the kick-up depth. Moreover, it adjusts with the number of needle punches, needle punch depth, the kind and usage-amount of oil agent, etc.

The entangled sheet is preferably entangled to have a mass ratio of 1.2 times or more, more preferably 1.5 times or more, with respect to the basis weight of the spunbond sheet before the entanglement step. is there. The upper limit is not particularly limited, but is preferably 4 times or less from the viewpoint of avoiding an increase in manufacturing cost due to a decrease in processing speed. In addition, the basis weight of the entangled sheet is appropriately selected according to the thickness of the target fiber entangled body, and specifically, for example, the handling property is in the range of 100 to 1500 g / m ² . From the point which is excellent in it.
The delamination force of the entangled sheet is preferably 7 kg / 2.5 cm or more, more preferably 9 kg / 2.5 cm or more. By setting the delamination force to be equal to or higher than these lower limit values, the shape retainability is improved, the fiber is less lost, and the sense of fullness and surface appearance of the resulting leather-like sheet are improved. Note that the delamination force is a measure of the degree of three-dimensional entanglement. By setting the delamination force to be equal to or greater than the above lower limit, the fiber density of the fiber entangled body can be sufficiently increased. The upper limit of the delamination strength of the entangled sheet is not particularly limited, but is preferably 30 kg / 2.5 cm or less from the viewpoint of entanglement treatment efficiency.

(3) Wet heat shrinkage treatment step Next, a shrinkage treatment step for producing a shrinkage entangled sheet (shrink web) by subjecting the obtained entangled sheet to wet heat shrinkage or hot water shrinkage will be described. The shrinkage treatment process is a process performed as necessary, and may be omitted. The shrinkage treatment step is a step of manufacturing a shrinkage-entangled sheet having a further increased degree of entanglement in order to make the fiber density of the fiber-entangled body obtained by shrinking the entangled sheet containing long fibers finer.
The wet heat shrinkage treatment is preferably performed under water absorption conditions such as steam heating and hot water treatment.
The steam heating condition is preferably a heat treatment for 60 to 600 seconds at an atmospheric temperature in the range of 60 to 130 ° C. and a relative humidity of 50% or more, more preferably 90% or more. In the case of such heating conditions, it is preferable because the entangled sheet can be contracted at a high contraction rate. In addition, by making relative humidity more than the said lower limit, the water | moisture content which contacted the fiber will be dried over comparatively long time, and it will become possible to fully shrink | contract.
The hydrothermal treatment conditions are preferably in the range of 50 to 130 ° C, more preferably in the range of 60 to 95 ° C. When the temperature is equal to or higher than these lower limits, the film is contracted at a high contraction rate. Moreover, there exists a tendency for shrinkage | contraction to become uniform easily because temperature becomes below an upper limit.

In the shrinking treatment, the entangled sheet may be shrunk so that the area shrinkage rate is preferably 20% or more, more preferably 30% or more. By contracting at a high contraction rate, a contracted web having a high fiber density and an even higher degree of fiber entanglement can be obtained.
The area shrinkage rate (%) is expressed by the following formula (1):
(Area of sheet surface before shrinking process−Area of sheet surface after shrinking process) / Area of sheet surface before shrinking process × 100 (1)
Is calculated by The said area means the average area of the area of the surface of a sheet | seat, and the area of a back surface.
Further, the fiber density may be increased by further heating and shrinking the shrink web obtained by the wet heat shrink treatment at a temperature equal to or higher than the heat deformation temperature of the composite fiber. In addition, the density of the fiber of the surface side and a back surface side can also be adjusted by carrying out a heating roll or heat-pressing on the surface side and a back surface side from different sides.

(4) Fiber bundle or hollow fiber entangled body formation process Next, the fiber bundle or hollow fiber which forms the entangled body of an ultrafine fiber bundle or a hollow fiber by melt | dissolving the water-soluble thermoplastic resin of a composite fiber in hot water The entangled body forming step will be described.
The ultrafine fiberization or hollow fiberization treatment is performed by dissolving and removing the water-soluble thermoplastic resin by subjecting the entangled sheet (or shrinkage entangled sheet) to hot water heat treatment with water, an alkaline aqueous solution, an acidic aqueous solution, or the like. It is a process of decomposing and removing.
As a specific example of the hot water heat treatment conditions, for example, as a first stage, after being immersed in hot water at 65 to 90 ° C. for 5 to 300 seconds, further as a second stage, hot water at 85 to 100 ° C. It is preferable to perform the treatment for 100 to 600 seconds. However, the hot water heat treatment need not be performed under two-stage treatment conditions, and may be performed under any one of the conditions. Moreover, in order to improve dissolution efficiency, you may perform the nip process by a roll, a high pressure water flow process, an ultrasonic process, a shower process, a stirring process, a stagnation process, etc. as needed.

(5) Impregnation step of polymer elastic body The leather-like sheet according to the present embodiment provides ultrafine fibers or hollow fibers to impart shape stability and thickness retention of the fiber entangled body and improve the texture and surface appearance. The purpose is to increase the morphological stability of the fiber bundle entangled body or to adjust the mechanical properties and texture of the fiber bundle entangled body before performing the treatment, or after performing the ultrafine fiber or hollow fiber treatment. As mentioned above, the entangled sheet or fiber entangled body is impregnated with the urethane resin composition and dried and solidified to contain the polymer elastic body in the entangled sheet or fiber entangled body.
For the impregnation of the urethane resin composition, it is preferable to use the urethane resin composition that is an aqueous liquid as the impregnating liquid, but other than the aqueous liquid may be used.

  Below, the case where the urethane resin composition which is aqueous liquid is used as an impregnation liquid is demonstrated in detail as an impregnation method of a polymeric elastic body. As the aqueous liquid, an aqueous solution obtained by dissolving a self-emulsifying aqueous polyurethane resin for forming a polymer elastic body in an aqueous medium such as water, or a self-emulsifying aqueous polyurethane for forming a polymer elastic body. Examples thereof include an aqueous dispersion in which a resin is dispersed in an aqueous medium such as water. The aqueous dispersion includes a suspension dispersion and an emulsion dispersion. In particular, from the viewpoint of excellent water resistance, it is more preferable to use an aqueous dispersion as described above.

As a method of impregnating the fiber entangled sheet with the urethane resin composition, for example, a method of applying the urethane resin composition to the fiber entangled sheet using a knife coater, a bar coater, or a roll coater, or a urethane resin composition And a method of immersing the fiber entangled sheet.
The polymer elastic body can be solidified by drying the fiber entangled sheet impregnated with the urethane resin composition. As a drying method, a method of heat treatment in a drying apparatus at 50 to 200 ° C., a method of heat treatment in a dryer after infrared heating, a method of heat treatment in a dryer after steam treatment, or drying after ultrasonic heating Examples thereof include a method of performing heat treatment with a machine, a method of combining these, and the like. Among them, the method of heat-treating with a dryer after steaming is preferable because the polymer elastic body and the fiber are easy to release and the film forming property of the polymer elastic body is easily maintained.
The urethane resin composition impregnated in the fiber entangled body is preferably gelled by being heated to about 40 to 100 ° C. before drying.

  The viscosity of the impregnating solution is preferably less than 10 Pa · s, more preferably less than 1 Pa · s, and more preferably less than 0.1 Pa · s, because the impregnation uniformity is excellent and the texture and surface appearance of the obtained leather-like sheet are uniform. Less than is particularly preferred. The viscosity of the impregnating liquid of the urethane resin composition immediately after preparation can be measured at 20 ° C. and 6 revolutions / minute using a single cylindrical rotational viscometer.

In the drying step after impregnating the fiber entangled sheet with the urethane resin composition that is an aqueous liquid, the water-based polyurethane resin migrates to the surface layer of the fiber entangled sheet, so that a uniform filling state is obtained. It may be difficult to obtain. In the present invention, the above-mentioned organic acid ammonium salt or inorganic acid ammonium salt, which is an ammonium salt whose pH is lowered by raising the temperature from room temperature to about 40 to 100 ° C., is added to the urethane resin composition, thereby , The water dispersion stability of the urethane resin composition at about 40 to 100 ° C. can be reduced, and migration can be suppressed.
Also, adjusting the particle size of the water-based polyurethane; reducing the water dispersion stability by adjusting the type and amount of the anionic group of the polymer elastic body; monovalent or divalent alkali metal salt or alkaline earth In combination with a metal salt, a nonionic emulsifier, an associative water-soluble thickener, an associative thermosensitive gelling agent such as a water-soluble silicone compound, or a water-soluble polyurethane compound at 40 to 100 ° C. Migration can also be suppressed by reducing water dispersion stability; In addition, you may make it migrate so that a polymeric elastic body may be unevenly distributed on the surface as needed. Further, the polymer elastic body may be preferentially fixed to the front surface side by setting the drying method and the applying method as different conditions on the front surface side and the back surface side.

When the polymer elastic body is applied to the fiber entangled body before the ultra-fine fiber treatment of the sea-island composite fiber or before the hollow composite fiber is hollowed, the fiber is removed when the water-soluble thermoplastic resin is removed. The voids formed inside the bundle or hollow fiber (the gap between the fiber and the polymer elastic body, the hole in the polymer elastic body, the gap inside the fiber, etc.) are maintained as a void even in the leather-like sheet, The fiber entangled body and the polymer elastic body are easily released. Therefore, it is preferable that the polymer elastic body is applied to the fiber entangled body before the ultra-fine fiber treatment for the sea-island type composite fiber or before the hollow type composite fiber is hollowed.
However, in the conventional water-based polyurethane, a polymer elastic body is applied before the sea-island type composite fiber is subjected to ultrafine fiber treatment or before the hollow type composite fiber is hollowed to form voids in the leather-like sheet. However, in the ultra-thinning process and the hollowing process, the polymer elastic body swells or deforms, and there is a problem that the elastic material adheres to the fibers or the pores are crushed and the voids disappear. Since the polymer elastic body used in the present invention is less swelled and deformed, it is possible to effectively maintain voids generated by extracting and removing the water-soluble thermoplastic resin.

  The polymer elastic body contained in the leather-like sheet may be impregnated in the fiber bundle as long as the average distance between the outer peripheral fiber of the ultrafine fiber bundle or the hollow fiber and the polymer elastic body is 1 μm or more. It may be attached to the outside of the bundle. When the polymer elastic body is impregnated in the fiber bundle, the rigidity can be adjusted by restraining the ultrafine fibers constituting the fiber bundle. The ratio of the polymer elastic body impregnated in the fiber bundle is 0 to 5% by mass with respect to the total amount of the polymer elastic body impregnated in the fiber bundle entangled body and the fiber bundle. preferable. When the ratio of the polymer elastic body existing in the ultrafine fiber bundle is 5% by mass or less, the flexibility and the surface appearance tend to be improved without excessively focusing the ultrafine fibers.

[Post-processing of leather-like sheet]
The fiber bundle entangled body obtained as described above is usually subjected to desired post-processing such as raising treatment, silver surface treatment, softening treatment, bipartite treatment, molding treatment, dyeing treatment, etc. according to various applications. Used.
The leather-like sheet of this embodiment preferably has a peel strength of 3.0 kg / 1.0 cm or more.
For example, when producing a silver-tone artificial leather, a coating layer made of a polymer elastic body is formed on the surface of the fiber bundle entangled body.
As a method for forming a coating layer made of a polymer elastic body, a method in which a dispersion or solution of a polymer elastic body is directly applied to the surface of a fiber bundle entangled body, or a coating layer formed on a release paper is used. A method of bonding to the surface of the fiber bundle entangled body is used. As the polymer elastic body used for forming the coating layer, a polymer elastic body conventionally used for the production of silver surface artificial leather can be used without any particular limitation. The thickness of the coating layer is not particularly limited, and specifically, for example, it is preferably in the range of 2 to 300 μm, more preferably 3 to 100 μm or less, particularly 3 to 80 μm, particularly 3 to 50 μm.

In addition, for example, in the case of producing napped-toned artificial leather, it has been conventionally used in the production of napped-toned artificial leather in which the surface of the fiber bundle entangled body is fluffed by buffing treatment using sandpaper or a needle cloth. The method is used.
Moreover, you may dye | stain a silver surface artificial leather and a nap-like artificial leather in any step of an ultrafine fiber formation process. In addition, if necessary, mechanical padding or shrinkage treatment in a dry state, relaxation treatment in a wet state using a dyeing machine or washing machine, softening agent treatment, flame retardant or antibacterial agent, deodorant, repellent A functional treatment such as a water / oil repellent, a treatment containing a silicone-based resin or a silk protein-containing treatment agent, a touch modifier such as a gripping resin, or a finishing treatment such as a colorant or an enamel coating resin may be performed.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the scope of the present invention is not limited to these examples. In the examples, parts and% are based on mass unless otherwise specified.

First, the evaluation methods used in this example will be described together.
<Average single fiber fineness>
The cross-sectional area of 100 fibers randomly selected with an optical microscope was measured, and the number average was obtained. From the average value of the fiber cross-sectional area and the specific gravity of the fiber, the fineness was calculated. In addition, the specific gravity of the fiber was measured based on JIS L1015 8.14.2 (1999).
<Weight swelling ratio of urethane film>
A film having a thickness of 250 μm ± 50 μm obtained by drying and solidifying an aqueous liquid of a self-emulsifying polyurethane resin at 50 ° C. was heat-treated at 120 ° C. for 5 minutes with a hot air dryer, and then 20 ° C. and 65% RH. Samples left for 1 day under these conditions were used as dry samples. Further, after the dried sample was further immersed in hot water at 90 ° C. for 60 minutes, an excess water droplet on the outermost surface of the film was immediately wiped off with JK Wiper 150-S (manufactured by Crecia Co., Ltd.). It was. The masses of the dried sample and the hot water swelling sample were measured, and the hot water swelling rate was determined according to the following formula.
Weight swelling rate (%) = [(mass of hot water swelled sample−mass of dried sample) / mass of dried sample] × 100
<Weight swelling ratio of composition film>
The urethane resin composition is made into a film while being gelled at 90 ° C. and 60% RH atmosphere, then heat-treated with a hot air dryer at 120 ° C. for 5 minutes, and then left at 20 ° C. and 65% RH for 1 day. This was used as a dry sample. Further, after the dried sample was further immersed in hot water at 90 ° C. for 60 minutes, an excess water droplet on the outermost surface of the film was immediately wiped off with JK Wiper 150-S (manufactured by Crecia Co., Ltd.). It was. The masses of the dried sample and the hot water swelling sample were measured, and the hot water swelling rate was determined according to the following formula.
Weight swelling rate (%) = [(mass of hot water swelled sample−mass of dried sample) / mass of dried sample] × 100

<Storage elastic modulus at 20 ° C. and 100 ° C.>
A film having a thickness of 250 μm ± 50 μm obtained by drying an aqueous dilution of a self-emulsifying water-based polyurethane resin at 50 ° C. was heat-treated with a hot air dryer at 120 ° C. for 5 minutes, and then 4 cm long × 0.5 cm wide A film sample was prepared. Then, after measuring the sample thickness with a micrometer, using a dynamic viscoelasticity measuring device (DVE Rheospectr, manufactured by Rheology Co., Ltd.), a frequency of 11 Hz and a temperature rising rate of 3 ° C./min. The dynamic viscoelasticity of the sample at 100 ° C. was measured, and the storage elastic modulus was calculated. In addition, when using 2 types of self-emulsification type polyurethane resins, the sample was created and measured separately, respectively, and the sum multiplied by the mass ratio was used as the value of the elastic modulus of the polymer elastic body.

<Average distance between peripheral fiber or hollow fiber of ultrafine fiber bundle and polymer elastic body>
The obtained leather-like sheet was cut in the thickness direction using a cutter blade to form a cut surface in the thickness direction. The obtained cut surface is dyed with osmium oxide, and the cut surface is randomly selected by a scanning electron microscope (SEM) at 10 locations on the cut surface, the ultrafine fiber bundle or hollow fiber perpendicular to the cut surface Was observed at a magnification of 1500 and an image was taken. In the obtained image, the average distance between the outer peripheral portion of the ultrafine fiber bundle or the outer peripheral portion of the hollow fiber and the polymer elastic body was determined. In addition, it calculated | required similarly about 20 total fiber bundles (or 20 hollow fibers) 2 pieces (or 2 pieces) per each image, and made the average of 20 measured values the average distance.
<Percentage of fibers with an average distance of 1 μm or more>
Similar to the above average distance measurement, images were taken at each of the 10 sections of the cut surface, and for 20 fiber bundles or 20 hollow fibers, out of the outer periphery of the ultrafine fiber bundle or hollow fiber, The ratio (%) of the part whose average distance is 1 μm or more was determined. In addition, it calculated | required similarly about 20 fiber bundles or 20 hollow fibers, and made the average of 20 measured value the ratio (%).
<Average pore diameter and the number of holes present in 10 μm square>
The obtained leather-like sheet was cut in the thickness direction using a cutter blade to form a cut surface in the thickness direction. And the obtained cut surface was dye | stained with osmium oxide, the said cut surface was observed by 1500 times about each 10 places selected at random with the scanning electron microscope (SEM), and the image | photographed image | photographed. And the diameter of all the holes was measured in the 10 micrometer square of the part applicable to the polymer elastic body of each image, and the average value was calculated | required. Moreover, the number of 0.2-10 micrometers holes in 10 micrometers square was also calculated | required. In addition, it calculated | required similarly in each image of 10 places, and made the average of those measured values the average hole number and the average hole diameter.

<Texture judgment>
A test piece obtained by cutting a leather-like sheet into about 20 cm square was used as an evaluation sample. Five panelists engaged in the handling of artificial leather touched the texture of the test piece and evaluated it according to the following criteria, and the evaluation given by the most panelists was taken as the texture evaluation result.
A: Compared to B, which is a general texture, an ideal texture that has a relatively very good fulfillment and softness. B: Artificial leather widely used as an upper material for sports shoes. General texture C: texture that is too hard or difficult to use for sports shoes

<Folding folds of artificial leather with silver tone>
A test piece cut out to about 20 cm square was used as an evaluation sample. The shape of the crease generated when the surface of the evaluation sample was valley-folded so that the upper and lower ends were aligned in the vertical direction was visually observed. And it determined with the following references | standards.
A: Dense and uniform wrinkles were generated on the folded surface similar to cowhide leather.
B: On the folded surface, a general fold wrinkle often observed in an upper material of a sports shoe, or a partial crease wrinkle occurred.
C: Rough wrinkles such as corrugated cardboard were generated on the folded surface.

<Evaluation of surface appearance of suede-like artificial leather>
Five panelists engaged in handling artificial leather visually evaluated the appearance of the suede-like artificial leather according to the following criteria, and the evaluation given by the most panelists was used as the appearance evaluation result.
A: The density of the napped surface is extremely high as a whole, and it is smooth without any roughness when touched with a hand.
B: The density of the napped surface is slightly rough as a whole, or is relatively high as a whole, but the density is clearly low and the rough parts are scattered. is there.
C: It is a rough raised surface as a whole, and there is considerable roughness when touched by hand.

[Example 1]
Modified PVA (sea component) and isophthalic acid-modified polyethylene terephthalate (island component) having a modification degree of 6 mol% were set at 260 ° C. so that the mass ratio of sea component / island component was 25/75. It was discharged from a base for melt composite spinning (number of islands: 25 islands / fiber). Then, by adjusting the ejector pressure so that the spinning speed was 3800 m / min, sea-island composite fibers having an average fineness of 2.5 dtex were deposited on the net, and a spunbond sheet having a basis weight of 27 g / m ² was obtained.

Next, twelve obtained spunbond sheets were stacked, and a web having a total basis weight of 325 g / m ² was produced by cross wrapping. And the mineral oil type oil agent was sprayed on the web as a needle | hook breaking prevention oil agent.
Then, using a bed plate punching device, needle punching was performed at 1500 punches / cm ² using needle needles with needle number 40 (9 barbs, kick-up depth 60 μm). Thereafter, needle punching was performed at 1000 punch / cm ² using a needle with needle number 42 (6 barbs, kick-up depth 40 μm) to obtain a long-fiber nonwoven fabric of sea-island type composite fibers. In addition, the area shrinkage ratio of the web by needle punching was 30%. The basis weight of the entangled sheet after needle punching was 450 g / m ² , and the delamination strength of the entangled sheet was 10 kg / 2.5 cm.
Next, the resulting entangled sheet was subjected to a wet heat shrinkage treatment at 90 ° C. in a 60% RH atmosphere for 30 seconds, and then subjected to a hot press treatment at 120 ° C. to reduce the thickness by 15%, thereby producing a shrink web. did. The area shrinkage rate of the shrink web was 44%, and the shrink web after pressing had a basis weight of 850 g / m ² , a thickness of 1.5 mm, and an apparent density of 0.61 g / cm ³ .

  Next, a self-emulsifying type polycarbonate-based polyurethane resin self-emulsified with an anionic group (weight swelling ratio 4.0% at 90 ° C. hot water, 20 ° C. storage elastic modulus 200 MPa, 100 ° C. storage elastic modulus 50 MPa, loss elastic modulus 1 part ammonium sulfate, 100 parts polyoxyethylene polyoxypropylene per 100 parts solid dispersion of 20% solids with a peak temperature of -24 ° C, polycarbonate polyol 100% polyol component, hydrogenated MDI component 100% diisocyanate component) An aqueous liquid of a urethane resin composition was prepared by mixing 5 parts of glycol (containing 85% polyoxyethylene units). The urethane resin composition had a weight swelling rate of 8% in 90 ° C. hot water. The shrink web was immersed in the aqueous liquid, and then heat-treated in a 90 ° C., 50% RH atmosphere for 30 seconds to form a heat-sensitive gel, and then dried at 140 ° C. And the modified | denatured PVA was melt | dissolved and removed by further immersing the shrink web after the process for 10 minutes in 95 degreeC hot water, and the leather-like sheet | seat was obtained by drying at 120 degreeC after that.

The leather-like sheet had an average single fiber fineness of ultrafine fibers of 0.1 dtex, a basis weight of 600 g / m ² , a thickness of 1.05 mm, and an apparent density of 0.57 g / cm ³ . Further, when the cross section in the thickness direction of the leather-like sheet was observed with a scanning electron microscope (1500 times magnification), the average distance between the polymer elastic body and the peripheral fibers of the ultrafine fiber bundle was 6.0 μm. The ratio of the fibers in the outer peripheral portion of the ultrafine fiber bundle having an average distance of 1 μm or more is 90%, the average pore diameter of the holes formed in the polymer elastic body is 3.0 μm, and the number of the holes is high. The number of elastic bodies was 12 per 10 μm square. At this time, pores having a pore diameter larger than 10 μm were not observed. The mass ratio of the fiber entangled body to the polymer elastic body was 86:14. The obtained leather-like sheet was evaluated according to the above evaluation method. The results are shown in Table 1.

The surface of the leather-like sheet obtained above was buffed with # 320 and further dyed in gray with 2% owf disperse dye. Further, a suede-like leather-like sheet was obtained by raising the surface by finishing buffing. In addition, there was almost no loosening and fraying of fibers during dyeing, and no loosening of fibers during buffing.
The suede-like leather-like sheet had a basis weight of 540 g / m ² , a thickness of 0.95 mm, and an apparent density of 0.57 g / cm ³ . In addition, the flexibility, the feeling of fullness, the feeling of surface fluff, and the dense crease state were good. The obtained suede-like leather-like sheet was evaluated according to the above evaluation method. The results are shown in Table 1.

A 30 μm-thick silver surface layer is formed by coating an aqueous polyurethane for the skin layer on the release paper and drying, and further, an aqueous polyurethane for the adhesive layer is coated on the surface of the silver surface layer and then dried to a thickness of 70 μm. An adhesive layer was formed. Then, a dry surface-forming treatment was performed by dry laminating the adhesive layer and the buffed surface on the surface of the leather-like sheet obtained above. The release paper was peeled off to obtain a leather-like sheet of artificial silver leather. The silver-tone artificial leather had a basis weight of 650 g / m ² , a thickness of 1.03 mm, and an apparent density of 0.63 g / cm ³ . In addition, the flexibility, the crease feeling, and the rounded volume feeling were good. The obtained silver-tone artificial leather was evaluated according to the above evaluation method. The results are shown in Table 1.

[Example 2]
A base for molten composite spinning (modified number of islands: 25 islands) of modified PVA (island components) and nylon 6 (sea components) set to 260 ° C. so that the mass ratio of sea components / island components is 50/50. Fiber). Then, the hollow composite fiber having an average fineness of 2.5 dtex was obtained by adjusting the ejector pressure so that the spinning speed was 3800 m / min.
And without performing wet heat shrinkage treatment, self-emulsifying type polycarbonate polyurethane resin (weight swelling ratio 3.5% at 90 ° C. hot water, 20 ° C. storage elastic modulus 450 MPa, 100 ° C. storage elastic modulus 100 MPa, peak of loss elastic modulus At a temperature of -23 ° C, polycarbonate polyol is 100% of the polyol component, hydrogenated MDI component is 100% of the diisocyanate component) and a solid content of 15% aqueous dispersion, 1.5 parts of ammonium sulfate, polyoxyethylene glycol ( Example 1 except that the shrink web was immersed in an aqueous liquid of a urethane resin composition obtained by mixing 7 parts of a polyoxyethylene unit 100% and 0.5 parts of a hydroxyalkyl cellulose thickener. The same process was performed. The urethane resin composition had a weight swelling ratio of 15% with 90 ° C. hot water.
The obtained leather-like sheet had an average single fiber fineness of hollow fibers of 1.0 dtex, a basis weight of 340 g / m ² , a thickness of 1.10 mm, and an apparent density of 0.31 g / cm ³ . Further, when the cross section in the thickness direction of the leather-like sheet was observed with a scanning electron microscope (magnification 1500 times), the average distance between the polymer elastic body and the hollow fiber was 4.0 μm, and the average distance between the polymer elastic body and the polymer elastic body. The ratio of the outer peripheral portion of the hollow fiber having a diameter of 1 μm or more is 70%, the average pore diameter of the holes formed in the polymer elastic body is 1.5 μm, and the number is 2 per 10 μm square of the polymer elastic body. It was. Moreover, the hole whose hole diameter is larger than 10 micrometers was not observed.
The mass ratio of the fiber entangled body to the polymer elastic body was 75:25. The obtained leather-like sheet was evaluated according to the above evaluation method. Moreover, the silver-tone artificial leather was produced by the method similar to Example 1, and evaluated according to the said evaluation method. The results are shown in Table 1.

[Comparative Example 1]
Instead of the self-emulsifying type polyurethane resin of Example 1, an aqueous polycarbonate polyurethane self-emulsified with a polyethylene glycol component (weight swelling rate at 90 ° C. hot water 10%, 20 ° C. storage modulus 200 MPa, 100 ° C. storage modulus 20 MPa In the same manner as in Example 1, except that peak temperature of loss modulus -30 ° C, polycarbonate polyol and polyethylene glycol 40/60 of polyol component and hydrogenated MDI component 100% of diisocyanate component were used. Like sheet, suede-like artificial leather. The urethane resin composition of Comparative Example 1 had a weight swelling rate of 120% with 90 ° C. hot water.
When the cross section in the thickness direction of the obtained leather-like sheet was observed with a scanning electron microscope (1500 times magnification), the polymer elastic body and the outer peripheral fiber of the ultrafine fiber bundle were bonded together, and the polymer elastic body and the ultrafine fiber were bonded. The average distance between the outer peripheral fibers of the fiber bundle is 0.2 μm, the ratio of the fibers in the outer peripheral portion of the ultrafine fiber bundle with an average distance of 1 μm or more to the polymer elastic body is 30%, and no holes can be observed in the polymer elastic body It was.
Moreover, the obtained suede-like artificial leather had a weight per unit area of 450 g / m ² , a thickness of 0.90 mm, an apparent density of 0.50 g / cm ³ , a large longitudinal elongation in the sea component extraction process, and a large decrease in thickness. . Then, the obtained leather-like sheet and the suede-like artificial leather were evaluated according to the above evaluation method. The results are shown in Table 2. The suede-like artificial leather had a hard and papery texture.

[Comparative Example 2]
Instead of the self-emulsifying type polyurethane resin of Example 1, an anionic self-emulsifying type polycarbonate polyurethane (weight swelling ratio at 90 ° C. hot water 6%, 20 ° C. storage elastic modulus 80 MPa, 100 ° C. storage elastic modulus 8 MPa, loss elasticity Using a water-soluble polyoxyalkylene compound (polyoxyethylene poly) with a peak temperature of -28 ° C., polycarbonate polyol being 100% of the polyol component, isophorone diisocyanate and hydrogenated MDI component being 60/40 of the diisocyanate component A leather-like sheet and a suede-like artificial leather were obtained in the same manner as in Example 1 except that a water-soluble silicone compound was used instead of (oxypropylene glycol). In addition, the weight swelling rate in the 90 degreeC hot water of the urethane resin composition of the comparative example 2 was 70%.
When the cross section in the thickness direction of the leather-like sheet was observed with a scanning electron microscope (1500 times magnification), the outer peripheral fibers of the polymer elastic body and the ultrafine fiber bundle were bonded, and the polymer elastic body and the ultrafine fiber bundle were The average distance between the outer peripheral fibers was 0.5 μm, the ratio of the outer peripheral portion of the ultrafine fiber bundle having an average distance from the polymer elastic body of 1 μm or more was 40%, and no pore diameter could be observed in the polymer elastic body.
The obtained suede-like artificial leather had a weight per unit area of 480 g / m ² , a thickness of 0.92 mm, an apparent density of 0.52 g / cm ³ , a large longitudinal elongation in the sea component extraction step, and a large decrease in thickness. Then, the obtained leather-like sheet and the suede-like artificial leather were evaluated according to the above evaluation method. The results are shown in Table 2. The suede-like artificial leather had a hard and papery texture.

[Comparative Example 3]
Instead of the self-emulsifying type polyurethane resin of Example 1, an emulsifier emulsifying type polycarbonate polyurethane (weight swelling ratio at 90 ° C. hot water 15%, 20 ° C. storage elastic modulus 900 MPa, 100 ° C. storage elastic modulus 550 MPa, loss elastic modulus The same as in Example 1 except that polycarbonate polyol is 100% of the polyol component, hydrogenated MDI component is 100% of the diisocyanate component, and sodium sulfate is used instead of ammonium sulfate. A leather-like sheet and a suede-like artificial leather were obtained by the method. The urethane resin composition of Comparative Example 3 had a weight swelling rate of 60% with 90 ° C. hot water.
When the cross section in the thickness direction of the leather-like sheet was observed with a scanning electron microscope (1500 times magnification), the average distance between the polymer elastic body and the outer peripheral fibers of the ultrafine fiber bundle was 6.0 μm, and the average of the polymer elastic body The ratio of the fibers in the outer peripheral part of the ultrafine fiber bundle having a distance of 1 μm or more was 90%, the average pore diameter of the polymer elastic body was 2.5 μm, and the number was 6/10 μm square of the polymer elastic body. Further, particles having an average particle size of 0.3 μm were observed.
The obtained suede-like artificial leather had a basis weight of 590 g / m ² , a thickness of 1.05 mm, and an apparent density of 0.56 g / cm ³ . Then, the obtained leather-like sheet and the suede-like artificial leather were evaluated according to the above evaluation method. The results are shown in Table 2. The suede-like artificial leather had a hard texture.

  According to the present invention, a leather-like sheet having flexibility, surface appearance, and fullness like natural leather can be obtained. Artificial leather using the leather-like sheet is preferably used as a material for leather-like products such as shoes, balls, furniture, vehicle seats, clothing, gloves, baseball gloves, bags, belts and bags.

Claims (9)

A leather-like sheet composed of a fiber entangled body composed of fibers having an average single fiber fineness of 0.001 to 10 dtex, and a polymer elastic body contained therein,
The fiber entangled body has at least one of an ultrafine fiber bundle and a hollow fiber, and the polymer elastic body is self-emulsified with a water-soluble polyoxyalkylene compound, an organic acid ammonium salt or an inorganic acid ammonium salt, and an anionic group. A urethane-like composition comprising a self-emulsifying water-based polyurethane resin, wherein the average distance between the outer peripheral fiber or the hollow fiber of the ultrafine fiber bundle and the polymer elastic body is 1 μm or more Sheet.   The fiber entangled body is composed of an ultrafine fiber bundle or a hollow fiber, and the ratio of the outer peripheral portion of the ultrafine fiber bundle or the hollow fiber whose average distance from the polymer elastic body is 1 μm or more is the outer periphery of the ultrafine fiber bundle or the hollow fiber. The leather-like sheet according to claim 1, which is 60% or more of the part.   3. The leather-like sheet according to claim 1, wherein in the self-emulsifying aqueous polyurethane resin, 50% by mass or more of the polyol component is a polycarbonate-based polyol, and 50% by mass or more of the diisocyanate component is hydrogenated MDI.   The leather-like sheet according to any one of claims 1 to 3, wherein the self-emulsifying aqueous polyurethane resin has a storage elastic modulus of 10 to 500 MPa at 20 ° C and 100 ° C when the film is solidified.   The self-emulsifying water-based polyurethane resin has a weight swell ratio of 8% or less in 90 ° C. hot water treatment when solidified into a film, and a polymer elastic body obtained by solidifying the urethane resin composition into a film is The leather-like sheet according to any one of claims 1 to 4, wherein a weight swelling ratio in a hot water treatment at 90 ° C is 50% or less.   The leather-like sheet according to any one of claims 1 to 5, wherein the water-soluble polyoxyalkylene compound contains 60% by mass or more of polyoxyethylene units.   The leather-like sheet according to any one of claims 1 to 6, further comprising a silver-tone resin layer having a thickness of 1 to 300 µm on the surface of the leather-like sheet.   The leather-like sheet according to any one of claims 1 to 7, wherein the fibers present on the surface of the leather-like sheet are subjected to napping treatment. For an entangled sheet including a composite fiber composed of a water-soluble thermoplastic resin and a water-insoluble thermoplastic resin, a treatment for dissolving the water-soluble thermoplastic resin is performed, and the average single fiber fineness is 0.001 to 0.001. Forming a fiber entangled body having at least one of ultrafine fiber bundles and hollow fibers composed of fibers of 10 dtex;
A step of impregnating and drying and solidifying a urethane resin composition in the fiber entangled body or entangled sheet,
The urethane resin composition includes a water-soluble polyoxyalkylene compound, an organic acid ammonium salt or an inorganic acid ammonium salt, and a self-emulsifying aqueous polyurethane resin self-emulsified with an anionic group,
A leather-like sheet obtained by solidifying the urethane resin composition and having an average distance of 1 μm or more between the polymer elastic body contained in the fiber entangled body and the peripheral fibers or hollow fibers of the ultrafine fiber bundle Manufacturing method.