JPH06316877A - Production of flexible artificial leather having high abrasion resistance - Google Patents

Abstract

PURPOSE:To obtain a flexible artificial leather having high abrasion resistance by mixing a specific inorganic neutral salt to a forcedly emulsified aqueous polyurethane emulsion having a specific particle diameter and applying the obtained treating liquid to a nonwoven sheet composed of a layer of ultrafine fibers. CONSTITUTION:A flexible artificial leather having excellent abrasion resistance can be produced by applying (A) a treating liquid produced by mixing an inorganic neutral salt (preferably Glauber's salt (Na2SO4.10H2O)) to a forcedly emulsified aqueous polyurethane emulsion having emulsion particle diameter of 0.1-2mum to (B) a nonwoven sheet produced e.g. by laminating and interlocking a nonwoven sheet made of ultrafine fibers having a single fiber fineness of <=0.5d as a surface fiber layer to a woven fabric made of a polyester fiber and heating and drying the applied emulsion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing artificial leather which is soft and has good wear resistance. More specifically, the present invention is
A water-based polyurethane emulsion is applied to a non-woven sheet material composed mainly of ultrafine fibers having a single fiber fineness of 0.5 denier or less as at least a surface fiber layer, and dried by heating to produce an artificial leather which is soft and has good abrasion resistance. Regarding the method.

[0002]

2. Description of the Related Art It is generally known that artificial leather is obtained by adding various polymer compounds to a non-woven sheet material composed mainly of ultrafine fibers, and the polymer compound in this case is artificial leather. In order to obtain a soft and elastic texture and durability, and physical properties such as a dimensional stability method, an elastic polymer compound such as polyurethane is often used.

In addition, these elastic polymer compounds are often applied as an organic solvent solution to a non-woven sheet material and wet-solidified. However, the organic solvent used at this time is often a highly flammable and highly toxic substance, and it is necessary to pay great attention to the recovery of the solvent in order to prevent the risk of fire and toxicity. Further, the solvent is also expensive, and there is a problem that it takes a lot of cost to recover the water from the dilute solution.

Due to these various problems, various studies have been made to shift the elastic polymer compound added to the non-woven sheet material from the organic solvent type to the water-based emulsion type, but the water-based emulsion type is still used. An artificial leather which has a satisfactory texture and physical properties when used and is excellent in nap quality has not been obtained.

The reason for this is that when an aqueous polymer emulsion is applied to a non-woven sheet material and dried by heating, the particles of the polymer emulsion dispersed in water are linked to the movement of water, and the non-woven sheet material is formed. Phenomenon that adheres intensively to the surface layer of an object,
This is because a so-called migration phenomenon occurs. That is, due to this migration phenomenon, a large amount of the emulsion substance adheres to the surface layer of the sheet-like material and hardly adheres to the inner layer, resulting in low physical properties (for example, abrasion resistance). Only artificial leather with a hard texture that is extremely wrinkled can be obtained.

Further, since a large amount of the emulsion substance adheres to the surface layer, it is difficult to form naps even if the surface layer is raised by buffing or the like, and there is a problem that a good nap quality cannot be obtained. Conventionally, various attempts have been made to suppress the migration phenomenon in order to solve the above problems.
For example, a synthetic emulsion containing a gelling agent and a heat-sensitive accelerator as disclosed in JP-A-52-28904 is adjusted to a heat-sensitive temperature of 45 ° C. or lower, impregnated into a fiber base cloth and heated to 90 ° C. or higher. There is a method of gelling in a hot water bath.

This method is certainly effective in suppressing migration and can be carried out on a laboratory scale, but on an actual production scale, the loss of the emulsion in the hot water bath cannot be ignored, and in particular, the lower the concentration of the emulsion, the more likely it is. It occurs violently, the degree of contamination in the hot water bath changes over time, and the gelling property changes subtly, making it impossible to produce stable quality. Furthermore, since the heat-sensitive temperature is low, the emulsion tends to become unstable under the influence of room temperature and water temperature, which change throughout the year, and a product of constant quality cannot be produced.

Further, the nonionic surfactant as the heat-sensitive accelerator has an action of weakening the adhesive force between the resin and the fiber, and its effect is remarkable when the emulsion concentration is as low as 10% or less. In such a case, the fiber cannot be endured only by the entanglement of the fibers, a slip phenomenon occurs, the abrasion resistance is extremely reduced, and in the case of a non-woven sheet without a reinforcing cloth due to a knitted fabric, cutting often occurs during dyeing. Also, it seems that this is due to the weak adhesion, but the resin itself fell off during dyeing,
There are major problems such as adhesion to the dyeing machine wall and redeposition on the product surface.

Japanese Unexamined Patent Publication (Kokai) No. 57-39286 discloses that the polyurethane emulsion itself has a heat-sensitive coagulation ability in order to eliminate such a harmful effect of the addition of the heat-sensitive agent.
However, in this method, it is important to set the hot atmosphere during solidification, and as shown in the examples, it is possible if it is gelation by hot water treatment, but heat transfer is poor in heat drying, so gel It is difficult to suppress migration because of poor chemicalization.

Further, in these prior arts, single yarn 2.0 to 8.0 is used.
It is effective only in the region of relatively thick fibers of about d, and in the region having an ultrafine fiber layer of 0.5d or less as in the present invention, capillarity is severe and migration of emulsion particles is more likely to occur. I can't. In addition, when the non-woven sheet has a high basis weight, the effect is remarkable. Furthermore, what can be said in common with these conventional techniques is that
Since the technical idea is premised on the impregnation with a high-concentration emulsion of 20% or more, the texture of the obtained artificial leather becomes hard as a whole. Thus, in either method,
It has not only been easy to process, but it has not been easy to simultaneously satisfy quality, especially wear resistance and texture.

[0011]

DISCLOSURE OF THE INVENTION The inventors of the present invention have achieved the present invention as a result of extensive studies to solve the above problems. That is, an object of the present invention is to provide a method for industrially producing artificial leather that is flexible and has good wear resistance, using an aqueous polyurethane emulsion.

[0012]

The object of the present invention is to force a non-woven sheet-like article comprising a fiber layer mainly containing ultrafine fibers having a single fiber fineness of 0.5 denier or less as a surface fiber layer. An emulsified nonionic emulsion,
The average particle size of the emulsion particles constituting it is 0.1
This is accomplished by dissolving and mixing inorganic salts in a water-based polyurethane emulsion having a thickness of 2.0 μm, applying a treatment liquid, and heating and drying.

The present invention will be described in detail below. If the non-woven sheet material used in the present invention has a fiber layer mainly composed of ultrafine fibers having a single fiber fineness of 0.5 denier or less as the surface fiber layer, what structure is used as the layer connected to the surface fiber layer? A sheet material may be used. For example, the entire non-woven sheet-like material may be constituted by a fiber layer having the same structure as the surface fiber layer, and as a layer connected to the surface fiber layer, one surface is entirely covered by the surface fiber layer and three-dimensionally entangled. You may arrange | position the layer which consists of the knitted fabric which exists. In the latter case, any constituent sheet-like material may be connected to the lower layer of the knitted fabric and arranged.

The fiber material of the ultrafine fibers having a single fiber fineness of 0.5 denier or less is not particularly limited as long as it is used for ordinary artificial leather. For example, polyethylene terephthalate (PET), nylon 6, Nylon 66,
Polyacrylonitrile or the like can be used. As the ultrafine fibers, those obtained by direct spinning by ordinary wet, dry and melt spinning methods, and further by melt blown method, method of extracting and removing one component from sea-island type fiber and polymer blended fiber, split fiber method and the like can be obtained. Things can be used.

In the present invention, a non-woven sheet material having a surface fiber layer mainly composed of ultrafine fibers having a single fiber fineness of 0.5 denier or less obtained by the above method is applied. When the monofilament fineness is 0.5 denier or more, the rigidity of the fiber is large and the nap of the surface is strong, so that it is not possible to obtain the high-grade surface quality, touch feeling, and lighting effect specific to artificial leather.

Further, a small amount of warm water-soluble short fibers (for example, vinylon) may be mixed in the non-woven sheet material as long as the object of the present invention is not impaired. In that case, the mixing ratio is set to 50% or less. When it is 50% or more, adverse effects such as a reduction in the gripping force of the polyurethane resin and the occurrence of bubbles during dyeing are highlighted. As a method for obtaining a non-woven sheet, a card, a cross layer,
It can be obtained by producing a non-woven web by a dry method such as a random weber, or by dispersing ultrafine fibers in water by a wet papermaking method, and entangled and integrated by needle punching and fluid entanglement treatment.

By dissolving inorganic salts as a heat-sensitive agent in a water-based polyurethane emulsion under certain limited conditions and mixing them, the heat transfer efficiency in conventional heating and drying is poor, and the inventors of the present invention have an extremely fine particle size of 0.5 d or less. It is possible not only to suppress the migration, which was difficult to achieve with a high basis weight sheet made of fiber, but also to achieve 20%.
The present invention has been completed by obtaining new knowledge that a film can be formed by gelation even in a low-concentration emulsion having a concentration of less than 1.

When the cross section of the non-woven sheet material obtained by the method of the present invention is observed by an electron microscope, the urethane resin whose migration is suppressed adheres directly to the fiber without interposing the crystals of the inorganic salt, It was observed that the fibers were bonded and fixed. The crystalline salt migrated and adhered to the surface of the resin or fiber, and further to the front and back surfaces of the non-woven sheet material. As a reminder, the gelled non-woven sheet-like product was washed with water and the salt was removed, and the product was observed again with an electron microscope, but no change was observed in the resin adhesion state.

From this, it is considered that the urethane particles are bonded in the process of gelation, solidify while solidifying the resin film, and the salt migrates as an aqueous solution of the salt. Therefore, the performance of the resin as a binder is considered to be sufficient.

According to the present invention, even if the water-based polyurethane emulsion is impregnated at a low concentration, the physical properties, especially abrasion resistance, are not significantly deteriorated.
It is considered that this is largely due to the adhesion state of the resin, and that the resin adhesion state is essentially different from that of the conventional method in which the heat sensitive agent is replaced with a surfactant or hot water gelation is performed. Thinking.

According to the present invention, it is possible to impregnate a water-based polyurethane emulsion at a low concentration, so that the softening of the texture can be achieved at a stretch. Furthermore, if the method of the present invention is applied to a base fabric in which a woven or knitted material is enclosed and reinforced inside a non-woven sheet material,
Even with an extremely low concentration emulsion of 3 to 5%, abrasion resistance performance that can withstand practical use can be imparted. Moreover, since the aqueous polyurethane emulsion has a low concentration, the unique soft texture possessed by the ultrafine fibers can be obtained. Can hold.

Of course, even if a high-concentration emulsion of 10% or more is impregnated, the texture does not become hard, but rather a solid feeling is obtained. In the field of furniture and other materials,
A high basis weight of 200 g / m ² or more is required, but even in that case, a wide range of concentration conditions can be applied, and particularly when combined with a high concentration condition of 10% or more, a high degree of wear resistance is imparted,
For that reason, the texture is flexible and chewy, and it is never paper-like.

The constituent conditions of the present invention will be described in more detail. The water-based polyurethane emulsion of the present invention is a nonionic emulsion that is forcibly emulsified in water with high mechanical shearing force in the presence of an emulsifier such as a nonionic emulsifier or anionic emulsifier, and the average particle diameter of the emulsion particles is 0. The most distinctive feature is that the urethane emulsion particles of 1 to 2.0 μm are rather large.

Examples of the forced emulsification method for obtaining the water-based polyurethane emulsion of the present invention include, for example, a phase inversion emulsification method in which a liquid polyurethane polymer of which the reaction is completed is emulsified with the emulsifier, and at the same time when the terminal isocyanate prepolymer is emulsified and / or thereafter. Examples thereof include a prepolymer method obtained by completing the chain extension reaction with a chain extender such as amines to obtain a high molecular weight, and the prepolymer method is particularly preferable in order to obtain a sheet having particularly good abrasion properties.

In order to improve the emulsification dispersibility, a nonionic hydrophilic group such as a polymer adduct such as ethylene oxide or propylene oxide is introduced into the side chain of the polymer molecular skeleton of polyurethane, or heat resistance is improved. In order to improve the properties and hot water resistance, modification means by modifying the polyurethane itself such as by reacting a trifunctional glycol such as trimethylolpropane, a trifunctional amine or the like to form a crosslinked structure is also suitably used in the present invention. .

However, an anionic water-based polyurethane emulsion in which an anionic hydrophilic group such as a carboxylic acid group is introduced into the polymer molecular skeleton to improve the emulsification dispersibility, on the contrary, not only lowers heat resistance and hot water resistance, However, the migration of emulsion particles during drying cannot be sufficiently suppressed, and the effect of the present invention cannot be obtained.

In the water-based polyurethane emulsion of the present invention, if the average particle size of the emulsion particles is less than 0.1 μm, migration during drying cannot be suppressed and the soft and abrasion-resistant artificial leather of the present invention cannot be obtained. Moreover, it is difficult to carry out the method of the present invention industrially and stably. On the other hand, if it exceeds 2.0 μm, the stability of the emulsion is deteriorated, but the film-forming property as a resin is poor, and the drop-off at the time of dyeing and the abrasion resistance cannot be satisfied.

The inorganic salts mixed and added to the emulsion are neutral salts of alkali metals or alkaline earth metals, which are monovalent or divalent sulfates, nitrates and chlorides.
For example, NaCl, Na ₂ SO ₄ , NaNO ₃ , CaS
O ₄ , CaCl ₂ , MgCl _{2 and the} like can be mentioned. In terms of process control, availability of raw materials, economic efficiency, and pollution, Na ₂ SO ₄ is most effective.

The addition concentration of the inorganic salt cannot be generally determined because the gelation property varies depending on the type of salt, but it is preferably 1 to 10% with respect to the emulsion. Even if the water-based polyurethane emulsion of the present invention is heated, it does not heat-coagulate at less than 20%, but it should be adjusted by adding the inorganic salts so that heat-sensitive gelation occurs when heated to a temperature of 80 ° C. or less. Is. Addition of a large amount of inorganic salts may cause the emulsion to gel at room temperature.

The following are examples of the composition of the polyurethane component constituting the water-based polyurethane emulsion of the present invention. Examples of the polyol component include polyester diols such as polyethylene adipate glycol and polybutylene adipate glycol; polyether glycols such as polyethylene glycol and polytetramethylene glycol; and polycarbonate diols. Examples of the isocyanate component include aromatic diisocyanates such as diphenylmethane-4,4′-diisocyanate; alicyclic diisocyanates such as dicyclohexylmethane-4,4′-diisocyanate; aliphatic diisocyanates such as hexamethylene diisocyanate.

As the chain extender, glycols such as ethylene glycol; ethylenediamine, 4,4'-
Examples thereof include diamines such as diaminodiphenylmethane. Then, a raw material polyurethane can be obtained by appropriately combining the above-mentioned various components.

In the emulsion, if necessary, a UV absorber, a stabilizer such as an antioxidant, a coloring agent such as a pigment, a surfactant such as a penetrant, an antifungal agent, a thickener, polyvinyl alcohol, CMC. A water-soluble polymer compound such as the above, a heat sensation accelerator such as a polyvinyl methyl ether type, and the like can be added. The water-based urethane emulsion to which the inorganic salt is added can be applied to the non-woven sheet material by any method such as a conventional impregnation method, a spray method and a coating method.

The applied amount (solid content) of the polyurethane resin constituting the water-based polyurethane emulsion may be any value depending on the purpose. Non-woven sheet material 10
It is 3 to 100 parts by weight with respect to 0 parts by weight. Further, as a specific method of heating and drying, any heating means such as hot air drying, infrared heating, and high frequency heating can be applied.
Hot air dryers such as pin tenters and clip tenters are generally used in consideration of the ease of maintenance.

The drying temperature is equal to or higher than the gelation temperature of the water-based polyurethane emulsion having heat sensitivity. Generally, the gelling temperature of the emulsion is preferably 60 to 80 ° C., because it does not gel before heating. At least 1 in order to maximize the performance of the gelled resin
10 ° C. is necessary, and is preferably 130 ° C. or higher. However, considering the heat resistance of the resin and the deterioration of the fiber, 180 ° C or higher should be avoided.

The non-woven sheet material to which the method of the present invention is applied can be directly put into a dyeing machine as an original fabric for artificial leather to be finished as a product. In particular, the use of a jet kneading machine is effective because the flexibility of the raised hair and the flexibility can be further increased. Further, prior to applying the water-based polyurethane emulsion of the present invention to the non-woven sheet material, coloring the non-woven sheet material in advance by dyeing or the like can prevent loss of dye exhausted to the emulsion substance. It is preferable because it can be done.

[0036]

The present invention is illustrated by the following examples, which do not limit the scope of the invention. The physical properties were measured after circular staining of each sample. The measuring method of each measured value used in the description of the examples is as follows. Average particle diameter: Measured at a disk rotation speed of 3000 rpm by an optical transmission method centrifugal sedimentation method using water as a dispersion medium using an automatic particle size measuring device manufactured by Horiba Ltd. It is represented by the median diameter measured on a volume basis.

Flexibility; L1079-A method (45 °
Cantilever method) Abrasion strength; L1096 method (Martindale method)

Example 1 A PET ultrafine fiber having a single fiber fineness of 0.1 denier was produced by the direct spinning method, and the length thereof was 5 m.
The short staple fibers cut into m were dispersed in water to obtain a papermaking slurry. This slurry was made into a paper to produce a nonwoven sheet having a basis weight of 50 g / m ² . The above-mentioned non-woven sheets were laminated on both sides of a plain woven fabric made of PET fiber of 75 denier / 36 filaments and having a basis weight of 50 g / m ² , and three-dimensionally entangled and integrated by jetting a high-speed water stream. High-speed water flow has a hole diameter of 0.1 m
It was jetted at a pressure of 30 kg / cm ² from a straight-flow jet nozzle of m.

The laminated sheet has a suction device on the lower surface 80
It was placed on a wire mesh and a high-pressure water stream was made to collide at a position 30 mm from the nozzle. This operation was performed from both the front and back sides of the laminated sheet to produce a sheet-like material having a basis weight of 150 g / m ² and a thickness of 0.55 mm. The surface of this sheet was buffed using # 400 emery paper at a paper speed of 700 m / min. To this, a polyether-based water-based polyurethane emulsion having an average particle size of 0.3 μm (Daiichi Kogyo Seiyaku Co., Ltd. “Superflex” forced emulsification type, nonionic solid content 45% by weight) was added at a concentration of 7% and Na ₂ S as a heat-sensitive agent.
A mixed solution containing O ₄ 5% was prepared.

When this prepared solution was heated with stirring, a gelled product was observed at 60 ° C. (By the way, the same emulsion of 7% concentration without addition of the heat sensitive agent was heated to 85 ° C., but no gelled product was formed. I was not able to admit.). The above sheet-shaped material was impregnated with this prepared solution, and was squeezed with a mangle so that the pickup rate was 150%. Then, it was heated and dried for 3 minutes in a pin tenter dryer at 130 ° C.

A part of this non-woven sheet was washed with water and dried before dyeing, and the cross section was observed with an electron microscope. As a result, it was found that the resin was evenly attached to the central layer. When the above-mentioned non-woven sheet was circularly dyed without washing with water and dried, a suede-like artificial leather having satisfactory physical properties and texture and excellent nap quality was obtained. The physical properties of this suede-like artificial leather are shown in Table 1.

Example 2 The non-woven sheet material used in Example 1 was prepared by adding the following three types of polyether-based water-based polyurethane emulsions (0.08 μm, 1.
4 μm, 2.2 μm) (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., “Superflex” forced emulsification type, nonionic, solid content 45% by weight) were each mixed to a concentration of 7%, and Na ₂ SO 4 was used as a heat-sensitive agent.
_The non-woven sheet is impregnated with a fixed solution of 45%,
A suede-like artificial leather was obtained in the same manner as in Example 1. The physical properties of these artificial leathers are shown in Table 1 as Examples 2-1, 2-2 and 2-3.

(Comparative Example 1) The experiment was carried out without adding Na ₂ SO ₄ as a heat-sensitive agent to 7% concentration of the water-based polyurethane emulsions having average particle diameters of 0.3 and 1.4 μm used in Examples 1 and 2, respectively. The same composition as in Example 1 was applied to the non-woven sheet, but all had a hard and wrinkle-prone texture,
The abrasion strength was also extremely poor and no surface nap was developed. The physical properties of this artificial leather are shown in Table 1.

[0044]

[Table 1]

(Comparative Example 2) An anionic water-based polyurethane emulsion having an average particle diameter of 0.3 and 1.4 μm was added to the non-woven sheet material used in Example 1 (“Superflex series, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.”). , Solid content 40%) 7%
The mixture was prepared and impregnated with Na ₂ SO ₄ 5% as a heat-sensitive agent to a concentration, squeezed at a pick-up rate of 150%, heat-dried for 3 minutes in a pin tenter dryer at 130 ° C., and then circular dyed without washing to finish.

However, in any of the particle sizes, the heat-sensitive gelation was insufficient, surface naps did not appear at all, and the cardboard-like hard texture was obtained. Further, the same experiment was conducted by changing the heat sensitive agent to 5% of MgCl ₂ , but the result was the same.

(Example 3) Using the same papermaking slurry as in Example 1, a nonwoven sheet having a basis weight of 120 g / m ² was produced. The non-woven sheet of 290 g / m ² was produced in the same manner as in Example 1 by laminating the non-woven sheet on both sides of a plain weave fabric made of PET fiber of 75 denier / 36 filament and having a basis weight of 50 g / m ² . The surface was buffed with # 400 emery paper.

To this, a polyether-based water-based polyurethane emulsion having an average particle size of 0.3 μm (“Superflex” forced emulsification type manufactured by Daiichi Kogyo Seiyaku Co., nonionic, solid content 45% by weight) was added as a heat-sensitive agent at a concentration of 7%. Na ₂ SO ₄ 5
%, And the solution was impregnated with a mangle to squeeze the pick-up rate to 170%. Then, it was heated and dried for 4 minutes by a pin tenter dryer at 150 ° C. This non-woven sheet was dyed with a circular dyeing machine without washing with water and dried to obtain a thick type suede-like artificial leather having a thickness of 1.00 mm. The feeling, abrasion resistance and surface nap quality were all satisfactory.

Example 4 To the non-woven sheet used in Example 1, 3 parts of a polyether-based water-based polyurethane emulsion having an average particle size of 0.6 μm (“Superflex” solid content of 43% by weight manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) was used. % And 15% concentration, and impregnated with a preparation liquid containing 6% NaCl as a heat-sensing agent, and the pick-up rate was reduced to 140% with a mangle. Then, it was heated and dried for 3 minutes by a pin tenter dryer at 140 ° C. This non-woven sheet was dyed with a circular dyeing machine without washing with water and dried to obtain a suede-like artificial leather having a thickness of 0.50 mm.

The physical properties shown in Table 2 are as follows. The one impregnated at a concentration of 3% has an extremely soft texture and wear resistance of 500.
It was perfect for light clothing at 0 times. Again 1
The product impregnated at a concentration of 5% had a high apparent density of the product and had a feeling of fulfillment, and was suitable for a clothing field where a finish was required without feeling a paper texture at all.

[0051]

[Table 2]

Example 5 A PET ultrafine fiber having a single fiber fineness of 0.1 denier was produced by the direct spinning method, and the length was 5 m.
It was cut into m pieces and dispersed in water to prepare a slurry for papermaking, and a sheet having a basis weight of 75 g / m ² was produced, which was used as a surface layer component.

As the back layer component, nylon 66 monofilament fineness 1.0 denier cut into 10 mm was similarly dispersed in water to prepare a sheet having a basis weight of 100 g / m ² . The two-component non-woven sheets were laminated, treated with a high-speed water stream having a pore diameter of 0.1 m at a water pressure of 40 kg / m ² , and three-dimensionally entangled and integrated. The sheet-like material was buffed with # 400 emery paper at a paper speed of 900 m / min for the ultrafine system layer on the surface.

This non-woven sheet material had an average particle size of 0.8 μm.
m Polyether water-based polyurethane emulsion (Daiichi Kogyo Seiyaku Co., Ltd., "Superflex" solid content 45% by weight) was impregnated with a preparation solution containing 9% concentration of NaCl 6% as a heat-sensitive agent, and picked up with a mangle of 130%. I narrowed it down to become. Then, it was heated and dried for 3 minutes in a pin tenter dryer at 130 ° C.

This was subjected to circular dyeing at 120 ° C. in a mixed bath of dispersion / acid dye without washing with water. The finished product without cutting for dyeing had good mechanical properties including surface quality, texture and abrasion resistance. This was suitable as a shoe material.

[0056]

As described above, since a specific water-based polyurethane emulsion is applied to a non-woven sheet material mainly composed of ultrafine fibers and heated and dried, it is possible to provide an artificial leather which is soft and has good abrasion resistance.

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Claims (2)

[Claims] 1. A non-ionic emulsion forcibly emulsified in a non-woven sheet material comprising a fiber layer mainly comprising ultrafine fibers having a single fiber fineness of 0.5 denier or less as a surface fiber layer, It is characterized in that it is obtained by applying a treatment liquid in which inorganic salts are dissolved and mixed to an aqueous polyurethane emulsion having an average particle diameter of emulsion particles constituting the same of 0.1 to 2.0 μm, and heating and drying the same. A method for producing artificial leather having good wear resistance. 2. The softener according to claim 1, wherein the inorganic salt is a neutral salt composed of an alkali metal or an alkaline earth metal and is a monovalent or divalent sulfate, nitrate or chloride. A method for producing artificial leather with good wear resistance.