JPH0881886A - Production of nubuck-tone artificial leather - Google Patents

Abstract

PURPOSE: To obtain a nubuck-tone artificial leather having soft handle and excellent surface characteristics such as coloring properties on the surface and buckling resistance without requiring extremely fining treatment at two stages. CONSTITUTION: A web is formed from conjugate fibers comprising two or more polymers and subjected to needle punching in the direction of thickness of the web to make an interlaced synthetic fibrous base. The interlaced synthetic fibrous base is impregnated with a first elastic polymer, compressed and squeezed. Immediately after the operation, before recovery of the compression, the interlaced synthetic fibrous base is impregnated with a second elastic polymer, compressed and squeezed and the first and the second elastic polymers are coagulated. Then the conjugate fibers constituting the interlaced fibrous base are extremely fined. The non-napped surface of the interlaced fibrous base is provided with a liquid containing a solvent for the second elastic polymer and the second elastic polymer is partially dissolved or swollen. The liquid is removed, the interlaced fibrous base is solidified and the surface of the interlaced fibrous base treated with the solvent-containing liquid is treated with a paraffin.

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 a nubuck-like artificial leather, and more particularly to a surface nubuck which does not require a two-step fiber microfine treatment and eliminates a rubber-like appearance and texture. The present invention relates to a method for producing a nubuck-like artificial leather which is excellent in feeling and particularly has excellent surface properties such as surface coloring, buckling resistance (wrinkle resistance of the surface), which is soft in texture.

[0002]

2. Description of the Related Art As a conventional method for producing artificial leather having a napped appearance, for example, a fiber assembly such as a woven fabric, a knitted fabric or a non-woven fabric is impregnated with a high molecular polymer and coagulated, and then the surface thereof is polished. The way is done.

Further, in order to control the appearance of the artificial leather, the napped fiber length is changed, the apparent density of the fiber aggregate is regulated, the impregnation amount of the elastic polymer is increased, and the buff condition is controlled. Is commonly practiced.

However, in these methods, the napped fiber length becomes long, and a good appearance can be obtained as a suede or velour-like artificial leather, but an artificial leather having a dignified appearance as a nubuck tone with a short fiber length is obtained. I can't get it.

In order to solve this problem, as a method of shortening the napped fiber length, for example, Japanese Patent Laid-Open No. 3-161576.
Japanese Patent Laid-Open Publication No. 2004-242242 discloses a step of expressing the ultrafine fibers from the composite fibers in the surface layer portion, and then applying a polymer elastic body to coagulate them, and mainly to make the composite fibers in the inner layer into ultrafine fibers. A method consisting of a step process has been proposed.

[0006] However, in this method, the step of making the composite fiber extremely thin has two steps, the number of steps is increased and the operation becomes complicated, and the polymer elastic body is added after the fiber is made extremely thin. There is a problem that the polymer elastic body is firmly bonded to the ultrafine fibers in the outermost surface layer, and the appearance and the feel become rubber-like.

On the other hand, in JP-B-61-32432, a liquid which is a solvent for the elastic polymer and a non-solvent for the fibers is applied to the surface of the suede-like sheet, and a part of the elastic polymer is added. It has been proposed to dissolve or swell and then re-solidify, followed by raising or styling. However, this method is intended to prevent the falling of surface fluff of the napped sheet in the fiber napped suede with long naps on the napped surface, and a method for producing a nubuck-like artificial leather like the present invention. Is completely different.

Furthermore, Japanese Patent Publication No. 63-5518 discloses that
By forming at least two non-porous layers on the surface of the base sheet material by coating, surface performance, flexibility, drapeability,
It is described that the color tone is improved. However, in such a coating method, due to the buffing treatment, it is not possible to obtain a nubuck-like artificial leather having short naps, a high surface fiber density, and excellent homogeneity of the napped state,
Further, when the non-porous layer is formed, the air permeability is deteriorated and the inside of the leather becomes damp.

[0009]

SUMMARY OF THE INVENTION Therefore, the present invention has two features.
It does not require a step-by-step ultrafine treatment of the fiber, eliminates the rubber-like appearance and texture, and has an excellent surface nubuck feeling. In particular, the texture is soft, and the surface properties such as surface coloring and buckling resistance are excellent. It is an object of the present invention to provide a method for producing a nubuck-like artificial leather.

[0010]

According to the present invention, as means for solving the above-mentioned problems, at least (a) 2
Forming a web from ultrafine fiber composite fibers comprising one or more high molecular weight polymers, and (b) in the thickness direction of the web, 50
Needle punching is performed at a barb-through punching number of 0 to 3000 / cm ² to prepare an entangled fibrous base material, and (c) the entangled fibrous base material is impregnated with the first elastic polymer, Compression squeeze to 60-90% of the thickness of the substrate, (d) immediately after that, before the compression is restored, a second elastic polymer is applied and impregnated while the compression is restored. Compression squeeze to 70 to 95% of the thickness of the above to solidify the first and second elastic polymers, and (e) after that, the composite fibers constituting the entangled fibrous base material are extremely thinned, f)
Then, after applying a liquid containing the solvent of the second elastic polymer to the non-puffed surface of the entangled fibrous base material to dissolve or swell a part of the second elastic polymer, There is provided a method for producing a nubuck-like artificial leather, characterized in that the liquid is removed and solidified, and (g) a solvent-containing liquid-treated surface of the entangled fibrous base material is subjected to a buffing treatment.

In the method of the present invention, the ultrafine composite fiber is a composite fiber formed by composite spinning, mixed spinning or the like from two or more kinds of high molecular weight polymers having different properties, and at least one kind of composite fiber is used. Dissolving and removing high molecular weight polymers,
Alternatively, a material that can be made extremely fine by splitting due to physical or chemical action is used.

Particularly, a composite fiber composed of two or more kinds of high molecular weight polymers having different solvent solubility (for example, sea-island type composite fiber)
It is preferable to dissolve and remove at least one kind of high molecular weight polymer from among the above to make it ultrafine.

In the method of the present invention, specific examples of the high molecular weight polymer forming the ultrafine fibers include polyamides such as nylon 6, nylon 66 and nylon 12, and polyesters such as polyethylene terephthalate and polybutylene terephthalate.

In addition to these ultrafine fiber-forming high molecular weight polymers, high molecular weight polymers having different properties (for example, solvent solubility) used as a dissolution-removing component and a binding component, in addition to the above polyamide and polyester, Polyethylene, copolymerized polyethylene with vinyl compounds such as vinyl acrylate and vinyl acetate, polypropylene, high molecular weight polyethylene glycol, polystyrene,
Examples thereof include copolymerized polystyrene and polyacrylate in which vinyl compounds such as vinyl acrylate and vinyl acetate are copolymerized.

Further, as a combination of high molecular weight polymers for splitting by physical or chemical action, polyamides such as nylon 6, nylon 66 and nylon 12 and polyesters such as polyethylene terephthalate and polybutylene terephthalate are used. And a combination thereof.

The composite fiber is applied to a known card, random webber, cross layer or the like to form a web.

The web thus obtained is subjected to needle punching at a barb penetration punching number of 500 to 3000 lines / cm ² , preferably 800 to 2000 lines / cm ² in the thickness direction of the web. , Creating an entangled fibrous base material. Barb punch punching number 500 /
When it is less than cm ² , the entanglement of the entangled fibrous base material is insufficient, the strength is insufficient, and the choke mark property of the finished base material is also insufficient, resulting in a poor nubuck-like appearance.
On the other hand, if the number is more than 3000 fibers / cm ² , the entangled fibrous base material is excessively subjected to needle punching, the damage is increased, the base material is sagged, and the strength is lowered, which is not preferable.

Here, the number of barb penetrating punches is
It is a numerical value converted into a value per 1 cm ² when punching is performed using a needle having at least one barb and a first barb of the needle penetrates in a thickness direction of the web.

In the method of the present invention, the entangled fibrous base material thus prepared by needle punching is impregnated with the first elastic polymer to obtain 60 to 90% of the thickness of the base material.
Compression squeeze immediately after, and immediately before compression is restored, a second elastic polymer is applied and impregnated while recovering compression and compression squeezed to 70-95% of the thickness of the substrate, The first and second elastic polymers are solidified.

Examples of the first and second elastic polymers include polyurethane elastomers, polyurea elastomers, polyurethane / polyurea elastomers, polyacrylic acid resins, acrylonitrile / butadiene elastomers, styrene / butadiene elastomers. Among them, polyurethane elastomers are mentioned. Polyurethane-based elastomers such as polyurea elastomer, polyurethane-polyurea elastomer and the like are preferable. These polyurethane elastomers include at least one polymer glycol selected from polyether glycol, polyester glycol, polyester ether glycol, polycaprolactone glycol, polycarbonate glycol, etc. having an average molecular weight of 500 to 4000, and 4,4 '
-Organic diisocyanates such as diphenylmethane diisocyanate, xylylene diisocyanate, tolylene diisocyanate, dicyclohexylmethane diisocyanate, and isophorone diisocyanate, and low-molecular glycols, diamines, hydrazines, or organic acid hydrazides,
It is obtained by reacting with a chain extender selected from hydrazine derivatives such as amino acid hydrazide.

The first elastic polymer and the second elastic polymer are
The same elastic polymer may be used, but different elastic polymers are preferably used. In particular, the first elastic polymer does not contain a polyoxyethylene chain, or 5 because it has good coagulability and can economically produce a nubuck leather sheet having a soft texture.
% Or less is preferably a polyurethane elastomer containing a polyoxyethylene chain in the polymer, and further,
In order to color the inside, it is preferable to contain an organic pigment and / or an inorganic pigment.

The second elastic polymer is a polyurethane elastomer containing a polyoxyethylene chain in an amount of 5 to 30% in the polymer in order to improve the dyeability and light fastness of the surface layer of the leather sheet. A polyurethane elastomer composed of an alicyclic and / or aliphatic isocyanate is preferable. In the former case, if the polyoxyethylene chain is less than 5%, sufficient dyeing property cannot be obtained, and if it exceeds 30%, wet swelling becomes too large.

Further, in order to impregnate each of the elastic polymers into a entangled fibrous base material, the entangled fibrous material is usually used in the form of an organic solvent solution or dispersion (including an aqueous emulsion) of the elastic polymer. The base material is impregnated, and the concentration is preferably 7 to 20% for the first elastic polymer, more preferably 10 to 18%, and the concentration for the second elastic polymer is the first. A concentration that is 5% or less higher than the concentration of the elastic polymer is preferable. With this combination, a softer texture as a nubuck-like artificial leather can be obtained, and moreover, the denseness of the nubuck-like surface and the fiber nap density can be increased,
It is possible to obtain a nubuck-like artificial leather that is more excellent in surface color development and buckling resistance.

In the method of the present invention, after the entangled fibrous base material is impregnated with the first elastic polymer, the thickness of the base material is 6
Compression squeeze to 0-90%, immediately afterwards, before the compression is restored, the second elastic polymer is applied and impregnated while recovering the compression to 70-95% of the thickness of the substrate. It is necessary to squeeze the compression.

By such treatment, the ratio of the first elastic polymer to the fibers of the lower layer of the entangled fibrous base material is
Fiber: First elastic polymer = 90: 10 to 50:50, maintaining a soft texture as artificial leather, and second elasticity to the fiber of the surface layer of about 0.1 to 0.5 mm from the surface Polymer ratio is fiber: second elastic = 75: 25
Within the range of 40:60, the layer is more densely formed than the lower layer,
A nubuck-like surface having an excellent appearance can be obtained.

If the entangled fibrous base material is impregnated with the first elastic polymer and compression squeezed to less than 60% of the base material thickness, it is difficult to squeeze stably.
When the compression squeeze exceeds about%, the amount of the second elastic polymer to be processed thereafter becomes small, the first elastic polymer is mixed on the surface, and the coloring property due to dyeing is uneven, and The nubuck feeling is inferior and the buckling resistance is also inferior. Further, the first elastic polymer is impregnated and compression squeezed, and after the compression is restored, the second elastic polymer is impregnated.
Not only is the impregnation amount of the second elastic polymer reduced,
It is not suitable because the impregnation becomes uneven.

Further, when the compression squeeze after impregnating with the second elastic polymer is less than 70% of the substrate thickness, the impregnated amount of the second elastic polymer becomes small, and the surface nubuck feeling, It is unsuitable because it is inferior in dyeing color development and buckling resistance. If it exceeds 95%, the amount of the second elastic polymer adhering to the surface layer is too large and it is buffed later. To
It will be difficult to obtain a uniform nubuck-like surface and the texture will be hard.

The impregnated elastic polymer is then coagulated in the entangled fibrous base material. As a concrete method for coagulating the elastic polymer, any of known wet coagulation method and dry coagulation method may be used. Further, the solidified state of the elastic polymer in the entangled fibrous base material is preferably porous.

After the entangled fibrous base material is impregnated with the elastic polymer and solidified, at least one high-molecular polymer is dissolved and removed, or the composite is formed by a known method such as cleavage by physical or chemical action. Makes fibers very fine. Particularly, in the method of the present invention, it is preferable to use a composite fiber composed of two or more kinds of high molecular weight polymers having different solvent solubility, and to dissolve and remove at least one high molecular weight polymer to make it ultrafine. .

For example, in a sea-island type composite fiber containing a polyester or polyamide as an island component and a vinyl polymer as a sea component, for example, benzene, toluene, xylene, trichloroethane, tetrachloroethane or the like is used as a dissolution remover of the sea component. To be Further, in a composite fiber in which polyester and polyamide are arranged so as to be able to be ultrafine, when one component is dissolved and removed, or when swelling and splitting, as a dissolution remover or swelling agent for polyester, for example, water An aqueous alkaline solution such as sodium oxide or potassium hydroxide is used, and examples of the dissolution remover or swelling agent for polyamide include lower alcohol solutions of alkali metal salts or alkaline earth metal salts, and acids such as formic acid, sulfuric acid, and hydrochloric acid. Used.

The average fineness of the ultrafine fibers constituting the entangled fibrous base material after the ultrafine treatment is preferably 0.4 denier or less in order to obtain a homogeneous and textured surface appearance, and particularly preferably 0. It is 001-0.2 denier.

The non-napped surface of the entangled fibrous base material composed of the ultrafine fibers thus produced, that is, the surface which has not been napped, is directly treated with the liquid containing the solvent for the second elastic polymer. . When treated with such a liquid after the nap treatment, the texture of the surface of the finally obtained sheet becomes hard and the napped state of the surface becomes inhomogeneous, and the nubuck artificial leather targeted by the present invention is obtained. Absent.

The liquid containing the solvent for the second elastic polymer may be a good solvent for the elastic polymer such as dimethylformamide, diethylformamide, dimethylacetamide, tetrahydrofuran or dioxane, or water, alcohol,
A mixture of methyl ethyl ketone and a part of the second elastic polymer is preferably used. The liquid containing the solvent of these second elastic polymers, because it is necessary to dissolve or swell a part of the second elastic polymer, the solvent,
It is desirable to contain at least 50% or more, preferably 70% or more.

The method of applying the liquid containing the solvent of the second elastic polymer to the surface of the ultrafine entangled fibrous base material is not particularly limited, and for example, coating with a gravure coater or spray coater, or Examples include a method in which the liquid is applied to the surface of a support such as a release paper, and contacted and integrated with the surface of the entangled fibrous base material before drying to transfer the liquid. In this step, it is preferable to apply the liquid while lightly nipping the base material with a gravure roll or the like.

Then, the liquid containing the solvent of the second elastic polymer is removed, and a liquid removal treatment is performed in order to solidify the second elastic polymer. Examples of the liquid removal treatment method include a dry method using a hot air dryer and a wet method of immersing in a liquid such as water. The dry method uses a liquid containing the second elastic polymer. It is preferable because the amount can be reduced and the effect of fixing fibers is large. It is preferable to repeat the application of the liquid and the removal of the liquid at least 2 to 6 times. The higher the number, the higher the homogeneity. However, if the number of times exceeds 6, the surface tends to become hard. The amount of liquid applied to the non-napped surface of the entangled fibrous base material is 10 to 6 per time.
It is preferably 0 g / m ² . Liquid application amount is 10g
If it is less than / m ² , the surface napped fiber length becomes long, making it difficult to obtain the desired nubuck-like artificial leather.
If it exceeds / m ² , the surface becomes hard and it takes time to remove the liquid.

By this liquid application process and liquid removal process,
After the second elastic polymer is dissolved or swelled, it is re-solidified,
Enhancing the bond between the ultrafine fibers and the elastic polymer on the surface of the entangled fibrous base material to hold down the fibers, and by the buffing treatment described later, it has sharp choke mark properties, short hairs, and a napped state is uniform. It becomes possible to manufacture artificial leather having an excellent surface nubuck feeling.

Then, the surface of the entangled fibrous base material treated as described above is subjected to a buffing treatment. Before the buffing treatment, the surface is treated with a smooth or small embossing roll, a calender roll, a flat plate press or the like. May be. Buffing can be performed by a conventional method using sandpaper, a brush, a grindstone, or the like. However, if you do buffing with something that is too coarse or buffing for a long time, the treated surface will be rough and you will not be able to obtain the target nubuck-like artificial leather, so be careful I won't. When using sandpaper, the abrasive particles should be 240 mesh or more, preferably 4 mesh or more.
It is desirable that the mesh is finer than 00 mesh.

After the buffing process is performed as described above,
It can be dyed and colored in any color, and can be treated with a softening agent, a water repellent, a slime agent or the like, if necessary.

[0039]

In the method of the present invention, 500 to 3000 lines / cm ²
Since the fibers are sufficiently entangled by performing needle punching with the number of barb penetrating punches, the entangled fibrous base material having sufficient strength, excellent choke mark property, and no damage or fatigue is obtained.

Further, the first elastic polymer is impregnated, compression squeezed to 60 to 90% of the thickness of the substrate, and immediately thereafter, the second elastic polymer is applied before the compression is restored. ,
Impregnation is performed while recovering compression, and the thickness of the base material is 70 to
By compressing and squeezing to 95% to solidify the first and second elastic polymers, the structure of the elastic polymer and the fiber is optimized, and when the buffing process is performed, short fluff and short surface fiber density are obtained. It is possible to obtain a nubuck-like artificial leather which has a high degree of nap and is excellent in the uniformity of the napped state. Furthermore, since the impregnation of the elastic polymer and the compression squeeze are performed in two stages, the surface layer and the lower layer of the base material can be set to have optimum characteristics, and for example, the lower layer of the base material can be artificial leather. It is possible to have a structure suitable for giving a soft texture to the surface layer, and a surface layer having excellent dyeing property, light fastness, buckling resistance, etc., and a structure suitable for giving a uniform nubuck-like surface. Become.

Further, after the ultrafine treatment, the non-napped surface of the substrate is treated with the liquid containing the solvent of the second elastic polymer, so that the ultrafine fibers and the elastic polymer are bonded on the treated surface. The fibers can be pushed up to a higher extent, and in combination with the above-mentioned requirements, the buffing treatment makes it possible to produce a nubuck-like artificial leather having an excellent surface nubuck feeling.

Further, in the method of the present invention, the ultrathinning of the composite fiber is performed in one step, and the ultrathinning treatment in two steps is not required.

Moreover, since the entangled fibrous base material is impregnated with the elastic polymer and coagulated, the composite fiber is ultrafine, and therefore, the prior art which is produced to apply the elastic polymer after the fiber is ultrafine. It is possible to completely eliminate the problem of (2), that is, the elastic polymer is firmly bonded to the ultrafine fibers in the outermost surface layer, and the appearance and the feel become rubber-like.

[0044]

The present invention will be described in detail below with reference to examples.

[Examples 1 to 3 and Comparative Examples 1 and 2] Nylon 6 and polyoxyethylene ether-modified low density polyethylene were chip-blended at a compounding ratio of 50:50, and were mixed and spun to have a fineness of 6 denier and a fiber length of 51 mm. A composite fiber was obtained. The resulting composite fiber was made into a web by a card and a cross layer. A needle rocker equipped with 3 barb needles was used for this web, and needle punching was performed with the number of barb penetrating punches shown in Table 1.
After heating for 4 minutes in a hot air oven at 0 ° C., nipping was performed with a cooling press roll to prepare an entangled fiber substrate material having an apparent density of 0.30 g / cm ³ , a thickness of 1.87 mm and a basis weight of 560 g / m ² . .

Next, a polybutylene adipate having a molecular weight of 1400 was reacted with polytetramethylene ether glycol having a molecular weight of 2050, 4,4'-diphenylmethane diisocyanate and ethylene glycol, and the nitrogen content based on isocyanate was 4. A dimethylformamide solution (concentration 15%) of 2% polyurethane elastomer (first elastic polymer) was prepared, and a brown toner for coloring was added thereto.

The above-mentioned pressed entangled fibrous base material was dipped in this solution to be impregnated with the polyurethane elastomer solution, and between a doctor blade made of Swedish steel having a thickness of 0.2 mm and a metal rotating roll. Compression squeezed to 70% of fibrous base material thickness.

Then, before the compression of the fibrous base material is recovered, a 17% dimethylformamide solution of the same polyurethane elastomer as the above-mentioned first elastic polymer is degassed and supplied, and while the compression is recovered, the second It was impregnated as an elastic polymer and compression squeezed to 80% of the thickness of the fibrous base material in the same manner as above.

Thereafter, the polyurethane elastomer was solidified by immersing it in a 10% dimethylformamide aqueous solution. Then, it was thoroughly washed in warm water of 40 ° C. and dried in a hot air oven of 120 ° C. to obtain an elastic polymer-impregnated base material having a fiber / polyurethane elastomer ratio of 75:25.

Next, dipping and nip were repeated on this base material in toluene at 80 ° C. to dissolve and remove polyethylene, and the composite fiber was ultrafine. After that, toluene contained in the base material is removed azeotropically in warm water at 90 ° C.
The fibers were dried in a hot air drier at 0 ° C. to the equilibrium moisture content of the fibers or less. The average fineness of the obtained nylon 6 ultrafine fibers is 0.0
It was 3 denier.

Then, about 20 g / m ^{2 of} dimethylformamide was applied to the surface of the base material using a gravure coater and dried in a hot air dryer at 120 ° C.
Buffing processing was performed with a buffing machine equipped with 400 mesh sandpaper.

The fibrous base material subjected to the buffing treatment is
A gold-containing dye (Kayakaran Brown 2GL200) was dyed in an aqueous solution containing 10% of the substrate weight and having a bath ratio of 1/20, and fixed with tannic acid.

The characteristics of the sheet thus obtained are as shown in Table 1, and the number of barb punchings is 500 to 30.
In the case of 00 lines / cm ² (Examples 1 to 3), a nubuck-like sheet having excellent surface coloring properties, buckling resistance, good texture and appearance was obtained. On the other hand, the number of barb punches is 5.
When it is less than 00 lines / cm ² (Comparative Example 1), the strength is insufficient and the bending durability is poor, and the surface nub feel is also poor.
When it exceeds 00 lines / cm ² (Comparative Example 2), the damage due to needle punching becomes large, and sagging occurs,
Furthermore, even if the number of needle punching is increased more than this,
The surface nubuck feel was almost unchanged, and the production efficiency was inferior.

[0054]

[Table 1]

In Table 1, ⊚ indicates extremely good, ∘ indicates good, and x indicates bad.

[Examples 4 to 7, Comparative Examples 3 to 6] Nylon 6 and polyethylene having a melt index of 20 were mixed with each other.
Melt extrusion was carried out from two extruders with a composition of 0:50, and a hollow splittable conjugate fiber having a fineness of 4.8 denier and a fiber length of 51 mm, which was bonded to 48 splits by a composite spinneret, was obtained. The obtained composite fiber was applied to a card and a cross layer to prepare a web. 3 on this web
Using a needle rocker equipped with a barb needle,
Needle punching was performed at a barb-through punching number of 2200 / cm ² , heated in a hot air oven at 150 ° C. for 4 minutes, and then nipped by a cooling press roll to give an apparent density of 0.32 g / cm ³ and a thickness of 1.75 mm. , Weight 560g
A entangled fiber matrix material of / m ² was obtained.

Next, a polyurethane elastomer having a nitrogen content of 4.0% based on isocyanate obtained by reacting polytetramethylene ether glycol having a molecular weight of 2050, 4,4'-diphenylmethane diisocyanate and ethylene glycol (first A dimethylformamide solution (concentration: 13%) of one elastic polymer) was prepared, and a blue toner for coloring was added thereto.

The above-mentioned pressed entangled fibrous base material was dipped in this solution to impregnate it with a polyurethane elastomer solution, and between a doctor blade made of Swedish steel having a thickness of 0.2 mm and a metal rotating roll. As shown in Table 2, compression squeezing was performed by changing the squeeze rate with respect to the thickness of the fibrous base material.

Next, before the compression of the fibrous base material is restored, polytetramethylene ether glycol having a molecular weight of 2050, polyethylene glycol having a molecular weight of 1540,
Polyurethane elastomer obtained by reacting 4,4'-diphenylmethane diisocyanate and ethylene glycol with a nitrogen content of 4.0% and a polyethylene glycol content of 15% based on isocyanate (second elastic polymer ) Dimethylformamide solution (concentration 15)
%) Is degassed and supplied, and impregnated while recovering the compression, and between the doctor blade and the metal rotating roll,
As shown in Table 2, compression squeezing was performed by changing the squeeze rate with respect to the thickness of the fibrous base material.

Then, the polyurethane elastomer was coagulated by immersing it in a 10% dimethylformamide aqueous solution. Then, it was thoroughly washed in warm water of 40 ° C and dried in a hot air oven of 120 ° C to obtain an elastic polymer-impregnated base material.

Next, dipping and nip were repeated on this substrate in toluene at 80 ° C. to dissolve and remove polyethylene, and the composite fiber was ultrafine. After that, toluene contained in the base material is removed azeotropically in warm water at 90 ° C.
The fibers were dried in a hot air drier at 0 ° C. to the equilibrium moisture content of the fibers or less. The average fineness of the obtained nylon 6 ultrafine fibers is 0.1.
It was denier.

Then, about 20 g / m ^{2 of} dimethylformamide was applied to the surface of the base material using a gravure coater and dried in a hot air dryer at 120 ° C.
Buffing processing was performed with a buffing machine equipped with 600 mesh sandpaper.

The fibrous base material subjected to the buffing treatment is
A gold-containing dye (Kayakaran Navy 2GL200) was dyed in an aqueous solution containing 15% of the substrate weight and having a bath ratio of 1/20, and then fixed with tannic acid.

The properties of the sheet thus obtained are as shown in Table 2 and the compression squeeze after impregnation of the first elastic polymer was made 60 to 90% of the substrate thickness and impregnated with the second elastic polymer. When the subsequent compression squeeze was set to 70 to 95% of the substrate thickness (Examples 4 to 7), a nubuck-like sheet with excellent texture and appearance, which was excellent in surface coloration and buckling resistance, was obtained. It was On the other hand, when the compression squeeze after impregnation with the first elastic polymer was set to less than 60% of the substrate thickness (Comparative Example 3), wrinkles were likely to occur during squeeze. When the compression squeeze after impregnation with the first elastic polymer exceeds 90% of the substrate thickness (Comparative Example 4), and the compression squeeze after impregnation with the second elastic polymer is 70% of the substrate thickness. When it is less than (Comparative Example 5), the impregnated amount of the second elastic polymer is small, the first elastic polymer is mixed on the surface, and the coloring property due to dyeing is uneven, resulting in a nubuck-like appearance. Was inferior, and the buckling resistance was also inferior. Furthermore,
When the compression squeeze after impregnation with the second elastic polymer was made to exceed 95% of the substrate thickness (Comparative Example 6), the amount of the second elastic polymer attached to the surface layer was too large, When it was buffed later, it was difficult to obtain a uniform nubuck-like surface and the texture was hard.

[0065]

[Table 2]

In Table 2, ⊚ indicates extremely good, ∘ indicates good, and x indicates bad.

COMPARATIVE EXAMPLE 7 In Example 7, the first elastic polymer solution was impregnated, compression squeezed to restore the compression of the fibrous base material, and then the second elastic polymer solution was impregnated. The treatment was performed under the same conditions as in Example 7 except that the treatment was performed.
The obtained sheet had a reduced amount of the second elastic polymer impregnated, the first elastic polymer was mixed on the surface, and uneven coloring was caused by dyeing, resulting in a poor nubuck-like appearance. Moreover, the buckling resistance was inferior.

Example 8 Instead of the polyurethane elastomer used as the second elastic polymer in Example 7, polytetramethylene ether glycol having a molecular weight of 2050, polyethylene glycol having a molecular weight of 1540, 4,
4'-diphenylmethane diisocyanate, p, p'-
Dimethylformamide solution of polyurethane elastomer having a nitrogen content of 4.0% and a polyethylene glycol content of 15% based on isocyanate obtained by reacting diaminocyclohexylmethane (concentration 15%)
Was used, and the other conditions were the same as in Example 7 for the treatment. The obtained sheet was excellent in surface color development and buckling resistance, exhibited a good nubuck-like appearance, and was particularly excellent in light fastness.

[Comparative Example 8] In Example 7, the treatment was performed under the same conditions as in Example 7, except that the substrate after the ultrathinning treatment was not coated with dimethylformamide by gravure roll. The obtained sheet had long surface napped fiber length, lacked sharp chalk mark properties, did not have a nubuck-like appearance, but rather had a suede-like appearance.

[Comparative Example 9] In Example 7, dimethylformamide was applied by gravure roll after buffing treatment on the surface of the base material after the ultrathinning treatment, but the surface texture became hard and the napped state was obtained. However, a good nubuck-like sheet could not be obtained.

[Examples 9 to 14] Nylon 6 and polyoxyethylene ether-modified low density polyethylene were chip-blended at a compounding ratio of 50:50, and fineness was 6 by mixing and spinning.
A composite fiber having a denier and a fiber length of 51 mm was obtained. The resulting composite fiber was made into a web by a card and a cross layer. A needle rocker equipped with a 3 barb needle was used for this web, and the number of punches through the barb was 18
Needle punching at 00 / cm ² and 150 ℃
After being heated for 4 minutes in the hot air oven of No. 1 and nipping with a cooling press roll, the apparent density was 0.30 g / cm ³ , and the thickness was 1.
An entangled fiber substrate material having a weight of 87 mm and a basis weight of 560 g / m ² was prepared.

Next, polyhexamethylene carbonate having a molecular weight of 1800 was reacted with polytetramethylene ether glycol having a molecular weight of 2050, 4,4'-diphenylmethane diisocyanate and ethylene glycol,
A dimethylformamide solution (concentration changed as shown in Table 3) of a polyurethane elastomer (first elastic polymer) having a nitrogen content of 4.2% based on isocyanate was prepared, and a brown toner for coloring was prepared with this solution. Was added.

The above-mentioned pressed entangled fibrous base material was dipped in this solution to be impregnated with the polyurethane elastomer solution, and between a doctor blade made of Swedish steel having a thickness of 0.2 mm and a metal rotating roll. Compression squeezed to 70% of fibrous base material thickness.

Next, before the compression of the fibrous base material is restored, polytetramethylene ether glycol having a molecular weight of 2050, polyethylene glycol having a molecular weight of 1540,
Polyurethane elastomer obtained by reacting 4,4'-diphenylmethane diisocyanate and ethylene glycol with a nitrogen content of 4.0% and a polyethylene glycol content of 15% based on isocyanate (second elastic polymer ) Dimethylformamide solution (concentration changed as shown in Table 3) was degassed and supplied, and impregnated while recovering the compression, and the thickness of the fibrous base material between the doctor blade and the metal rotating roll. Compressed and squeezed to 90%.

Thereafter, the polyurethane elastomer was solidified by immersing it in a 10% dimethylformamide aqueous solution. Then, it was thoroughly washed in warm water of 40 ° C and dried in a hot air oven of 120 ° C to obtain an elastic polymer-impregnated base material.

Then, dipping and nip were repeated on this base material in toluene at 80 ° C. to dissolve and remove polyethylene, and the composite fiber was ultrafine. After that, toluene contained in the base material is removed azeotropically in warm water at 90 ° C.
The fibers were dried in a hot air drier at 0 ° C. to the equilibrium moisture content of the fibers or less. The average fineness of the obtained nylon 6 ultrafine fibers is 0.0
It was 3 denier.

Then, about 20 g / m ^{2 of} dimethylformamide was applied to the surface of the base material using a gravure coater and dried in a hot air drier at 120 ° C.
Buffing processing was performed with a buffing machine equipped with 600 mesh sandpaper.

The fibrous base material subjected to the buffing treatment is
A gold-containing dye (Kayakaran Brown 2GL200) was dyed in an aqueous solution containing 15% with respect to the weight of the base material and having a bath ratio of 1/20, and fixed with tannic acid.

The properties of the sheet thus obtained are as shown in Table 3, and the solution concentration of the first elastic polymer was 7 to 2
0% and the solution concentration of the second elastic polymer is 5% or less higher than that of the first elastic polymer (Examples 10 to 1).
In 2), a nubuck-like sheet having excellent surface coloring and buckling resistance, good texture, and appearance was obtained, but when the solution concentration of the first elastic polymer became low (Example 9), napped hair was obtained. Was longer and the surface nubuck feeling tended to be slightly inferior.
When the difference between the solution concentrations of both elastic polymers is 0 (Example 13), the effect of improving the buckling resistance is not so great,
When the difference in concentration exceeds 5% (Example 14), when the viscosity becomes too high, defects such as pinholes are likely to occur and the texture tends to be slightly hard.

[0080]

[Table 3]

In Table 3, ⊚ is extremely good and ∘.
Indicates good, and Δ indicates slightly poor, but practically no problem.

[0082]

According to the production method of the present invention, it is not necessary to carry out a two-step fiber ultra-thinning process, the rubber-like appearance and texture are eliminated, and the surface nubuck feeling is excellent.
In particular, it is possible to produce a nubuck-like artificial leather that has a soft texture and is excellent in surface properties such as surface coloring and buckling resistance.

Claims (5)

[Claims] 1. A web is formed from at least (a) ultrafine fiber composite fibers composed of two or more high molecular weight polymers, and (b) 500 to 3000 strands / cm ^{2 in} the thickness direction of the web. Needle punching is performed by the number of punches through the barb to prepare an entangled fibrous base material, and (c) the entangled fibrous base material is impregnated with the first elastic polymer to obtain a thickness of the base material. Compression squeeze to 60-90%, (d) immediately after that, before compression is restored, a second elastic polymer is applied,
Impregnation is performed while recovering compression, and the thickness of the base material is 70 to
Compress and squeeze to 95% to solidify the first and second elastic polymers, (e) after which the conjugated fibers that make up the entangled fibrous base material are ultrafine, and (f) after which A liquid containing a solvent for the second elastic polymer is applied to the non-napped surface of the entangled fibrous base material to dissolve or swell a part of the second elastic polymer, and then the liquid is removed. And solidify (g)
A method for producing a nubuck-like artificial leather, which comprises subjecting a solvent-containing liquid-treated surface of the entangled fibrous base material to a buffing treatment. 2. The first elastic polymer is a polyurethane elastomer containing no polyoxyethylene chains or containing 5% or less of polyoxyethylene chains in the polymer, and an organic pigment and / or an inorganic pigment. The method for producing a nubuck-like artificial leather according to claim 1, which comprises: 3. The method for producing a nubuck-like artificial leather according to claim 1, wherein the second elastic polymer is a polyurethane elastomer containing 5 to 30% of polyoxyethylene chains in the polymer. 4. The method for producing a nubuck-like artificial leather according to claim 1, wherein the second elastic polymer is a polyurethane elastomer composed of an alicyclic and / or aliphatic isocyanate. 5. The first elastic polymer is impregnated with a solution or dispersion having a concentration of 7 to 20%, and the second elastic polymer is added at a concentration higher than that of the solution or dispersion of the first elastic polymer. The method for producing a nubuck-like artificial leather according to any one of claims 1 to 4, further comprising impregnating with a solution or dispersion having a high concentration of 5% or less.