JPH07229071A - Production of artificial leather using aqueous polyurethane resin - Google Patents

Abstract

PURPOSE:To obtain artificial leather having excellent surface elegance, flexibility and improved wear resistance, capable of extremely suppressing removal of a polyurethane resin during liquid flow dyeing, having no stain caused by the removal of the resin by providing a nonwoven sheetlike material consisting essentially of ultrafine fibers with a compound aqueous polyurethane emulsion. CONSTITUTION:In producing artificial leather by providing a nonwoven sheetlike material containing a fiber layer consisting essentially of ultrafine fibers having <=0.5 denier fineness of single fiber as a surface fiber layer with an aqueous polyurethane emulsion and drying by heating and using a treating solution prepared by predissolving an inorganic salt in the aqueous polyurethane emulsion and mixing, an aqueous polyurethane emulsion having <=12% dissolution ratio of a resin film prepared by drying the aqueous polyurethane emulsion in N,N- dimethylformamide and tack of <=1.2g/cm bond strength after dry heat treatment at 130 deg.C is used to provide a method for producing artificial leather using an aqueous polyurethane 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 using a water-based polyurethane resin, and more particularly, when dyeing an artificial leather raw material made of a water-based polyurethane resin with a jet dyeing machine, urethane is used at the time of dyeing. TECHNICAL FIELD The present invention relates to a method for producing artificial leather that causes less resin loss and does not cause stains on the dyeing machine due to the urethane resin that is removed.

[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 composed mainly of ultrafine fibers and processing them to obtain artificial leather. An elastic polymer compound such as polyurethane is often used in order to obtain a soft and elastic texture as artificial leather and physical properties such as durability and dimensional stability. Moreover, these elastic polymer compounds are often applied as a solution dissolved in an organic solvent to a non-woven sheet-like material and wet-solidified. However, the organic solvent used at this time is often a flammable and highly toxic substance, and in order to prevent the risk of fire and toxicity, it was necessary to pay great attention to the recovery of the solvent. Further, the solvent is also expensive, and there is a drawback that it takes a lot of cost to recover the water from the dilute solution.
Due to these various drawbacks, various studies have been made to shift the elastic polymer compound applied to the nonwoven sheet-like material from the organic solvent type to the water-based polyurethane emulsion type. However, in the case of water-based polyurethane, it is necessary to apply sufficient heat for film formation, and the texture tends to be a hard one with a core like paper. Further, there is a problem that the migration of the emulsion particles in the drying step is severe and it is difficult to form an elegant surface which is a characteristic of artificial leather.

In the past, 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 in a laboratory scale, but in the actual production scale, the dropping of the emulsion into the hot water bath cannot be ignored, and especially in the case of low-concentration emulsion. The dropout occurs so much that the degree of contamination in the hot water bath changes with time and the gelation 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 a 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 this case, the entanglement of the fibers in the non-woven sheet cannot withstand it, and a slip phenomenon occurs between the fibers, resulting in the falling of the naps on the product surface and the abrasion resistance being extremely reduced, and the reinforcing cloth made of knitted fabric. In the case of non-woven sheets, cutting often occurs during dyeing. Further, although it is thought that this is due to the weak adhesion, the resin itself falls off during dyeing, causing a serious problem such as sticking to the wall of the dyeing machine or redepositing on the product surface.

The inventors of the present invention have previously made a nonionic urethane emulsion that has been forcibly emulsified and has an average particle size of 0.1 to 2.0.
Disclosed is a method for producing artificial leather, characterized in that a neutral salt containing a monovalent or divalent metal is dissolved and mixed as a heat-sensing agent in μm and heated and dried (Japanese Patent Application No. 5-124650).
issue). By this method, it was possible to make the artificial leather made of water-based polyurethane soft to the touch, strengthen mechanical properties centering on abrasion resistance, achieve high-grade surface quality, and make progress toward practical use. However, even in this method, there is a problem that the urethane resin falls off because it cannot withstand the hot water kneading action in the jet dyeing, which is the mainstream of dyeing of textile products including artificial leather. When the dyeing temperature is 130 ° C., the dropout phenomenon is particularly remarkable. The urethane resin that has fallen off agglomerates due to bubbles and feather dust in the dyeing bath, clogging the strainer part or adhering to the vapor phase machine wall and contaminating the dyeing machine. If the pollution progresses further, a part of it may be peeled off from the machine wall, or the cloth may be rubbed and redeposited on the cloth to cause stains.

Further, the physical properties of the artificial leather product are greatly deteriorated, and especially the deterioration of abrasion resistance is larger than expected, resulting in a poor feeling of fulfillment. Therefore, in some cases, it is necessary to attach the extra amount in anticipation of the dropout amount, resulting in high cost. In order to avoid such a trouble at the time of dyeing, there is also a method of impregnating and applying an aqueous polyurethane resin after dyeing (dying) before impregnating the aqueous polyurethane. However, the artificial leather made by this method generally lacks in feeling of fulfillment, has a strong core, and is not suitable for the field of clothing requiring a high degree of fashionability.
Reducing the amount of urethane resin impregnated in order to solve the texture that leaves the core not only gives the fabric a unique feeling of elasticity and no feeling of fullness, but it also has consumption performance such as abrasion resistance and dimensional stability. Will be significantly impaired. or,
Since the urethane resin is heated and dried at a high temperature of 100 ° C. or higher after dyeing, there is a possibility that the dyeing fastness may be deteriorated particularly in a dark color, and the dye formulation is naturally limited. As described above, a true industrial production technique has not yet been established for the artificial leather provided with the water-based polyurethane resin.

[0007]

DISCLOSURE OF THE INVENTION An object of the present invention is to dye an artificial leather raw material provided with a water-based polyurethane resin with a jet dyeing machine so that the urethane resin does not drop off at the time of dyeing, and the dropped urethane resin machine is used. It is an object of the present invention to provide a method for producing artificial leather that does not cause contamination due to adhesion to walls.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a non-woven sheet comprising, as a surface fiber layer, a fiber layer mainly composed of ultrafine fibers having a single fiber fineness of 0.5 denier or less. When an artificial leather is produced by applying a water-based polyurethane emulsion to a granular material and heating and drying, a method using a treatment liquid prepared by dissolving and mixing pre-cure inorganic salts as the water-based polyurethane emulsion in a method using a water-based polyurethane emulsion. The resin film made by drying has a solubility of 12% or less in N · N dimethylformamide (hereinafter DMF) and has an adhesive strength of 1.2 g / cm or less after 130 ° C. dry heat treatment. It is achieved by doing.

Generally, in the film formation of water-based polyurethane, a resin film is formed by bonding the emulsion particles by heating and drying. The strength of the film formation is different from the temperature during drying,
It largely depends on the polymer composition and the concentration of the surfactant added for emulsification. As a matter of course, if the film formation is weak, the adhesive performance as a binder and the strength and physical properties as a film are insufficient, and the film cannot be withstood and rubbed by hot water at 100 ° C. or higher, especially 130 ° C., and will fall off. .
As a result of intensive studies on the strength of film formation and the detachability by dyeing and kneading, the present inventors have found that the strength of film formation is closely related to the DMF dissolution rate. It is generally considered that the water-based polyurethane resin film is insoluble in DMF because it is crosslinked by heat. However, it has a strong swelling effect.
When immersed in the MF solution, the film swells and the weakly bonded portions are dissolved, so the strength of film formation can be expressed by the dissolution rate. As an example, in FIG. 1, 4,4'-dicyclohexylmethane diisocyanate (H ₁₂ MDI) and polytetramethylene glycol (PTMG) are used as basic skeletons.
Two types of nonionic water-based polyurethane emulsions having an average particle size of 0.5 μm and having different content ratios of surfactants for emulsification were used, and the heat treatment temperature of the resin film and DMF
The relationship of the dissolution rate is shown. The surfactant content is 10% for A type and 4 for B type based on the solid content of polyurethane resin.
%. It can be seen that the DMF dissolution rate decreases and the film formation is strengthened by decreasing the content of the surfactant and increasing the heat treatment temperature.

According to the study by the present inventors, when the heat treatment temperature of the resin film is 120 ° C. as a standard, the DMF dissolution rate of the resin film is 12% or less, preferably 8% or less, the liquid flow rate is 130 ° C. The dropout rate in dyeing can be kept to 10% or less in terms of polyurethane resin. The reason why 120 ° C. is used is that the dyeing temperature is 130 ° C. at the maximum and the performance of the resin is rigorously evaluated by adopting a heat treatment condition lower than the dyeing temperature in evaluating the resin film performance. Therefore, if the DMF dissolution rate is 12% or less at the heat treatment temperature of 120 ° C. or less, the film forming performance as a resin can be considered to be further excellent, which is effective for high-speed production at the time of increasing production.

A value of 10% or less of the dropping rate of the urethane resin in the jet dyeing at 130 ° C. corresponds to the dropping rate of the solvent-based polyurethane, and the film-forming property of the water-based polyurethane resin is comparable to the performance of the solvent-based polyurethane resin. You can think of it as being at a level. Solvent-based polyurethane has a non-zero rate in hot water spray dyeing, let alone considering that the molecular weight of polyurethane polymer polymerized by water dispersion through a surfactant is not as high as that of solvent-based polyurethane. It can be said that polyurethane is at an amazing level. This drop-off rate hardly changes even when a film is formed by a heat-sensitive gelling method containing a neutral salt. This is because the polyurethane resin and the salt are phase-separated in the process of gelation by heating and drying, and the salt does not hinder the film formation.

Another important point for achieving the object of the present invention is that the polyurethane resin does not have tackiness. By using an aqueous polyurethane resin whose DMF solubility is limited, most of the dropouts due to dyeing can be prevented, but as long as it has a molecular weight distribution as a polyurethane polymer, some of the low molecular weight regions are severe. Being under a liquid massage cloth, the bond is easily broken, and it is almost impossible to completely eliminate the drop. What is important is that the resin that has fallen off is not tacky and does not adhere to the dyeing machine. Especially when considering polyester as a material, it is desirable that the adhesiveness is low at a maximum of 130 ° C. In the actual dyeing process, the dyes are added one after another, so even if they are slightly dropped, if they are strongly adhered, they will adhere to the gas phase wall or dead part in the dyeing machine and cause contamination by accumulated deposits. According to a study by the present inventors, the adhesive strength as tackiness is 130.
If it is 1.2 g / cm 2 or less by dry heat treatment at 0 ° C., adhesion inside the machine can be substantially suppressed. The value of 1.2 g / cm is a level at which almost no sticky feeling is felt even if the polyurethane resin film dry-heat-treated at 130 ° C. is touched with a finger. At 2.0 g / cm, it feels quite sticky.

Next, the liquid kneading dyeing of the synthetic leather raw fabric produced by the method of the present invention will be described. The kneading effect by the liquid flow is determined by the nozzle structure, the liquid flow injection clearance (clearance), and the nozzle pressure. There are various nozzle structures according to the characteristics of the cloth, but a general structure is one that generates a vortex while jetting the cloth at an angle of 45 ° to 60 ° with respect to the running of the cloth. Since the flow rate of the circulation pump is constant, the relationship between the clearance (l) and the nozzle pressure (P) is (l). (P) = constant, regardless of the nozzle structure.
Therefore, the larger the clearance, the lower the maximum nozzle pressure. If the nozzle structure is fixed, the effect of the nozzle pressure is greater than the effect of the clearance on the kneading effect. The lower the pressure, the weaker the kneading effect, the poorer the runnability of the fabric, and the more spotted or wrinkled. Although it is in the direction of reduction for the loss of polyurethane, it is not the preferred direction in order to obtain a drapeable, full-textured feel and good brushing fluttering. Also, if the pressure becomes too high, the fabric will be severely damaged and the commercial value will be lost, and the running of the fabric will become unstable and uncontrollable. An appropriate pressure range is 0.
It is 5 to 2.5 kg / cm ² .

Next, the constitutional conditions of the present invention will be described.
The non-woven sheet material used in the present invention has a fiber layer mainly composed of ultrafine fibers having a monofilament degree of 0.5 denier or less as a surface fiber layer, and as a layer connected to the surface fiber layer. Any constituent sheet may be used. For example, a non-woven sheet-like material may be composed of 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 with the surface fiber layer and the three-dimensional entanglement is performed. You may arrange | position the layer which consists of the knitted fabric. In the latter case, an arbitrary constituent sheet may be connected to the lower layer of the knitted fabric and arranged. A non-woven sheet having a knitted fabric layer has sufficient strength and dimensional stability even against a kneaded cloth during dyeing, and a low polyurethane resin amount is preferable because it is low in cost and has a soft texture. . 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, and examples thereof include polyethylene terephthalate (PET), nylon 6 and nylon 66. , Polyacrylonitrile, etc. can be used.

The ultrafine fibers are those directly spun by ordinary wet, dry and contact spinning methods, further melt blown method, a method of extracting and removing one component from sea-island type fibers and polymer blend fibers, and split fibers. Those obtained by the thread method or the like can be used. In the present invention, a non-woven sheet-like 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 used. When the single fiber fineness is 0.5 denier or more, the rigidity of the fiber is high and the nap of the surface is strong, so that it is possible to obtain a high-grade surface quality, a feeling of touch, and a writing effect specific to artificial leather. Absent. Further, it is possible to mix a small amount of warm water-soluble short fibers (for example, vinylon) into the non-woven sheet material within the range not impairing the object of the present invention. The non-woven sheet material is a non-woven web formed from the above-mentioned various ultrafine fibers by a dry method such as a card, a cross layer, a random webber, or a wet papermaking method in which the ultrafine fibers are dispersed in water. Is manufactured, and is entangled and integrated by a needle punch, a fluid entanglement treatment, or the like.

The water-based polyurethane emulsion of the present invention is a nonionic emulsion which is forcibly emulsified in water with high mechanical shearing force in the presence of an emulsifier such as a nonionic emulsifier or a weak anionic emulsifier, and its emulsion particles. Has an average particle diameter of 0.1 to 2.0 μm, which is slightly larger than normal urethane emulsion particles. 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 having completed the reaction is emulsified with the emulsifier, and a terminal isocyanate is preliminarily emulsified and / or simultaneously with an amine. Examples thereof include a prepolymer method obtained by completing the chain extension reaction with a chain extender such as a class of compounds to obtain a polymer having 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 emulsifying dispersibility, an ethylene oxide or propylene oxide adduct or a weak carboxylic acid group is introduced into the side chain of the polymer molecular skeleton of polyurethane, and heat resistance and hot water resistance are added. For the purpose of improving, trifunctional glycol such as trimethylolpropane
Modification means by modification of the polyurethane itself, such as reaction with a trifunctional amine or trifunctional amine to form a crosslinked structure, is also suitably used in the present invention. In the water-based polyurethane emulsion of the present invention, the average particle size of emulsion particles is 0.1.
If it is less than μm, 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, such as monovalent or divalent sulfates, nitrates and chlorides. For example NaC
1, Na ₂ SO ₄ , NaNO ₃ , CaSO ₄ ,
Examples thereof include CaCl ₂ and MgCl ₂ . 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. Addition of a large amount of inorganic salts may cause the emulsion to gel at room temperature. Examples of the composition of the polyurethane component that constitutes the water-based polyurethane emulsion of the present invention include the following. Polyester diols such as polyethylene adipate glycol and polyethylene adipate glycol as the polyol component; polyethylene glycol, polytetramethylene glycol and other polyether glycols
Examples thereof include polycarbonate and bonnetdiol. As the isocyanate component, diphenylmethane-4,
Aromatic diisocyanate such as 4'-diisocyanate;
Examples thereof include 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, ultraviolet absorbers, stabilizers such as antioxidants, coloring agents such as pigments, alcohols such as penetrants, surfactants, anti-microscopic agents, thickeners, polyvinyl alcohols, etc. Le, CMC
A water-soluble polymer compound such as the above, a thermal sensation accelerator such as polyvinyl methyl ether type, and the like can be added. Nonwoven cloth of water-based polyurethane emulsion with addition of inorganic salts
As a method for applying to the cake-like material, any method such as a conventional impregnation method, a spray method and a coating method can be used. The applied amount (solid content) of the polyurethane resin constituting the water-based polyurethane emulsion may be any value depending on the purpose. Generally, it is 3 to 100 parts by weight based on 100 parts by weight of the non-woven sheet material.

Further, as a specific method of heating and drying, any heating means such as hot air drying, infrared heating, high frequency heating can be applied, but in view of the amount of equipment investment and the ease of maintenance, a pin tenter or a clip is used. A hot air dryer such as a tenter is generally used. 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 above emulsion is preferably set to 60 to 80 ° C., because it does not gel before heating. In order to fully exhibit the performance of the gelled resin, at least 110 ° C is necessary, and preferably 130 ° C or higher. However, considering the heat resistance of the resin and the deterioration of the fiber, 180 ℃
You should avoid the above.

[0021]

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

DMF dissolution rate: A stock solution of an aqueous polyurethane resin emulsion is coated on a glass plate with an applicator of 0.25 mm and dried in a greenhouse at 25 ° C. for 20 hours to form a film. Next, the above film together with the glass plate is put in a hot air dryer at 120 ° C. and heat treated for 20 minutes. Remove the polyurethane film from the glass plate, 1
Weight cut to a size of 0 cm square (W ₁ )
To measure. Next, after soaking in DMF stock solution (25 ° C.) for 6 hours, it was dried in a dryer at 60 ° C. and weighed (W ₂ ).
To measure. The dissolution rate is calculated from the weight loss of the polyurethane resin excluding the surfactant. Adhesiveness: A heat-treated film is prepared as described above. This polyurethane film was treated for 30 minutes in hot water of 130 ° C. assuming a dyeing step, and then treated at 80 ° C. for 15 minutes in a solution of caseisoda, thiourea dioxide and 2 g / l each, 60 Dry in a dryer at ℃. Onto this film, a non-woven sheet made of a polyester made of ultrafine fibers of 0.5 d / f or less was overlaid, sandwiched between glass plates in a sandwich shape, and treated in a hot air dryer at 130 ° C. for 30 minutes. At this time, the load of the glass plate applied to the film was constant at 15 g / cm ² . Take out the integrated film and non-woven sheet and cut it to a width of 2.5 cm, and measure the strength of the adhesive surface with a tensile strength and elongation measuring machine.

Flexibility; L-1079-A method (45 ° C.
Cantilever method) Abrasion strength; L-1096 method (Martindale method) Breaking strength; L-1096-A method (strip method) Tear strength; L-1096-D method (Pendulum method) (Example 1) A PET ultrafine fiber having a single fiber fineness of 0.1 denier was produced by the direct spinning method, and fine short fibers cut into a length of 5 mm were dispersed in water to prepare a papermaking thriller. This thriller was made into a paper to produce a non-woven sheet having a basis weight of 50 g / m ² . 75 denier / 36 filament PET
The above-mentioned non-woven sheet was laminated on both sides of a plain woven fabric made of fibers and having a basis weight of 50 g / m ² , and three-dimensionally entangled and integrated by jetting a high-speed water stream. The high-speed water stream was jetted at a pressure of 30 kg / cm ² from a straight-flow jet nozzle having a hole diameter of 0.1 mm.

The laminated sheet has a suction device 80 on the lower surface.
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 is performed from both front and back sides of the laminated sheet, and the basis weight is 150 g / m ² and the thickness is 0.55 mm.
A sheet-like product was produced. The surface of this sheet was buffed using a # 400 emery paper at a paper speed of 700 m / min. In addition to this
"Perflex" (forced emulsification type nonionic solids 45
%) A polyether-based water-based polyurethane emulsion having an average particle size of 0.5 μm, a DMF dissolution rate of 7%, an adhesive strength of 1.0 g / cm and a concentration of 6%, and a heat-sensitive agent of Na ₂ SO ₄ 3%. Impregnated with the mixed solution containing
Squeeze 1 so that the pickup rate is 150% with the mangle
It heat-dried for 3 minutes with a pin tenter dryer of 30 degreeC. A nozzle pressure of 1.0 g / cm was applied to this artificial leather fabric using a circular dyeing machine set to a bath ratio of 1:30 in a 70 l bath.
After dyeing with a blue-type disperse dye at a concentration of 10% at 130 ° C. for 30 minutes, thiourea dioxide and caseisodea at 2 g / l for each 8 g
After reducing and washing at 0 ° C. for 15 minutes, it was dried and finished. At this time, the removal rate of the urethane resin was as small as 5% as calculated from the weight change before and after dyeing. Also, after dyeing, a ^# 20 strainer was taken out and the adhered matter was observed, but there was almost no adhered matter, and it was possible to clean by simple water washing. The physical properties of the obtained artificial leather were as follows, and had a full-feeling texture and a high-quality feeling with raised brushing and fluttering.

[0025]

[Table 1]

Comparative Example 1 A non-woven sheet similar to that used in Example 1 was DM-coated with "Super Flex" manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.
Finished by processing, dyeing, and finishing under the same conditions as in Example 1 using the same polyether-based water-based polyurethane emulsion as in Example 1 except that the F dissolution rate is 14% and the tackiness is 3.5 g / cm in terms of adhesive strength. . The polyurethane resin dropout rate was 40%, which was surprisingly high. Adhesive deposits were found on the 20 ^# strainer after dyeing and could not be removed unless it was rubbed firmly with a wire brush. The physical properties of the obtained artificial leather are as follows, and it was a long nap that was rough with a fluffy texture without a tight texture.

[0027]

[Table 2]

(Example 2) The same artificial leather raw material as in Example 1 was dyed and finished with a circular dyeing machine at a nozzle pressure of 2.0 g / cm. At this time, the polyurethane resin dropout rate is 6%
After all it was few. 20 ^# There was no deposit on the strainer, and simple washing with water was sufficient. The physical properties of the obtained artificial leather were as follows, showing a graceful litting effect without leaving brushing or damage due to a soft texture with excellent drape property while leaving a fulfilling feeling.

[0029]

[Table 3]

(Comparative Example 2) The non-woven sheet used in Example 1
"Super Flex" series manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.
Polyester-based water-based polyurethane emulsion with a mean particle size of 1.0 μm (forced emulsification type nonionic fixed component 5
(0%), the DMF dissolution rate was 6%, which was good, but the tackiness showing a high adhesive strength of 5 g / cm was processed under the same conditions as in Example 1 and dyed and finished. The polyurethane resin dropout rate of this product was as low as 7%,
The 20 ^# strainer cannot be removed by simple washing with water and was cleaned with a wire brush. I could foresee that it would obviously cause a problem when a large amount of dyeing is performed.

Example 3 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 sheet was cut into m pieces and dispersed in water to prepare a papermaking slurber, and a sheet having a basis weight of 75 g / m ² was produced and used as a surface layer component. As the back layer component, a nylon 66 monofilament fineness 1.0 denier cut into 10 mm was similarly dispersed in water to produce a sheet having a basis weight of 100 g / m ² . The two-component non-woven sheet was 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. This sheet is a # 400 emery paper.
The ultrafine yarn layer on the surface was buffed with a paper at a paper speed of 900 m / min. This non-woven sheet has an average particle size of 0.8 μm.
m Polyether-based water-based polyurethane emulsion (Daiichi Kogyo Seiyaku Co., Ltd. "Superflex" solid content 45
%) DMF dissolution rate 6%, adhesive strength 1.2 g
One having a performance of / cm was prepared by adding NaCl 5% as a heat-sensing agent at a concentration of 11% and squeezed with a mangle so that the pickup rate was 120%. Then, it was heated and dried for 3 minutes by a pin tenter dryer at 130 ° C. This product was dyed and finished under the same dyeing conditions as in Example 1. The product was finished without cutting in the dyeing machine, and there was no problem with the urethane resin falling rate of 5%. Cleaning the strainer after dyeing was also easy because there were almost no deposits and no tackiness. The physical properties of the obtained artificial leather are as follows, and it was suitable as a backing material for shoes because it had a feeling of volume and sufficient mechanical strength.

[0032]

[Table 4]

(Comparative Example 3) The non-woven sheet used in Example 3
In addition, the DMF dissolution rate is 22%, and the tackiness is 1.2 in terms of adhesive strength.
g / cm. Other conditions were the same as in Example 3 except that the same aqueous polyether urethane emulsion was used. However, it could not be cut and finished as a product during dyeing.

[0034]

As described above, by adding a specific water-based polyurethane emulsion to a non-woven sheet-like material composed mainly of ultrafine fibers, the drop-off of polyurethane resin during jet dyeing can be greatly suppressed and dropped. Since there is no resin contamination, it is possible to provide an artificial leather that is industrially and stably, has an elegant surface quality, and is flexible and has good wear resistance.

[Brief description of drawings]

FIG. 1 shows the relationship between resin film, heat treatment temperature and DMF dissolution rate for two types having different surfactant contents.

Claims (1)

[Claims] 1. A water-based polyurethane emulsion is applied to a non-woven sheet-like material comprising a fiber layer mainly containing ultrafine fibers having a single fiber fineness of 0.5 denier or less as a surface fiber layer and heated and dried. When manufacturing artificial leather,
In the method using a treatment liquid in which inorganic salts are previously dissolved and mixed in the water-based polyurethane emulsion, the solubility of the resin film prepared by drying the water-based polyurethane emulsion in N / N dimethylformamide is 12% or less, and The adhesive strength after dry heat treatment at 130 ° C is 1.
A method for producing artificial leather using a water-based polyurethane resin, which comprises using a water-based polyurethane emulsion of 2 g / cm or less.