JP6792562B2 - Artificial leather base material, artificial leather and its manufacturing method - Google Patents

Description

The present invention relates to artificial leather having a texture and appearance similar to that of natural leather.

Conventionally, natural leather has been used as a high-class material in various fields such as clothing, bags, shoes, interior materials, and interior materials for vehicles. Since natural leather is expensive, artificial leather is widely used as a substitute. Artificial leather is mainly composed of an artificial leather base material in which a non-woven fabric is filled with a polymer elastic body. There are known silver-like artificial leather having a skin layer on the surface of such an artificial leather base material, and suede-like artificial leather in which fibers on the surface of the artificial leather base material are brushed.

Conventionally known general artificial leather base materials have many voids that are not filled with a polymer elastic body, so that they are less dense and full than natural leather. Therefore, when it is bent, it bends and bends, which is also called Poki-fold, and it folds without a sense of luxury. Further, as a method of producing a silver-like artificial leather in which a skin layer is provided on the surface of an artificial leather base material, a film for forming a skin layer is formed on a release paper, and the skin layer is artificially formed via an adhesive layer. A dry surface forming method that adheres to the surface of a leather base material is known. Further, a resin solution of a polymer elastic body for forming a grain surface resin layer on the surface of an artificial leather base material is applied by a method such as spray coating or reverse coating, and the resin solution is dried to form a grain surface resin layer. A direct coating method for forming a film is also known. In the dry surface forming method, the epidermis layer and the artificial leather base material are adhered to each other through the adhesive layer, so that the epidermis layer may be peeled off during use. Since the direct coating method does not bond the skin layer with an adhesive layer like the dry surface method, it has an excellent sense of unity between the grain resin layer and the artificial leather base material, and is also excellent in productivity. However, the direct coating method has a drawback that when applied to an artificial leather base material having many voids, the liquid sinks inside or the shape of the non-woven fabric emerges on the surface. These drawbacks of the direct coating method can be solved by increasing the thickness of the grain resin layer, but when the thickness of the grain resin layer is increased, the texture becomes rubber-like and tends to move away from the texture of natural leather. was there.

In order to solve the above-mentioned problems, there is a method of increasing the content ratio of the polymer elastic body in the non-woven fabric to reduce the voids, but when such a means is used, the artificial leather is made of the polymer elastic body. There was a problem that the repulsive feeling of the base material became high and the rubber-like and rigid texture became remarkable, which was far from the texture of natural leather.

By the way, conventionally, a technique of swelling nylon fibers with benzyl alcohol to soften them has been known (see Patent Documents 1 and 2 below). It has been known that a fabric having a soft texture can be obtained by swelling nylon fibers with benzyl alcohol by such a method.

Japanese Unexamined Patent Publication No. 2003-089984 JP-A-2003-08983

An object of the present invention is to provide artificial leather that has both a sense of fulfillment and suppleness like natural leather.

One aspect of the present invention includes a fiber entanglement of nylon-based ultrafine fibers of 1.5 dtex or less and a polymer elastic body impregnated in the fiber entanglement, and has an apparent density of 0.3 to 0.55 g / cm ³ . It is an artificial leather base material having a 20% strong vertical / horizontal ratio of 0.5 to 1.25 and a tear strength of 2.5 kgf / mm or more per 1 mm of thickness. A homogeneous artificial leather substrate with a relatively high apparent density and a 20% strong vertical / horizontal ratio of 0.5 to 1.25 provides a high sense of fulfillment and few large voids. A dense and highly smooth surface can also be formed. Further, since the tear strength per 1 mm of thickness is 2.5 kgf / mm or more, it is possible to maintain a supple texture in spite of a high sense of fulfillment. Further, when the grain surface resin layer is formed by using the direct coating method, the resin liquid for forming the grain surface resin layer is less likely to sink into the artificial leather base material, so that silver is not given a rubber-like texture. A surface resin layer can be formed.

Further, the artificial leather base material preferably has an elongation rate of 6.5% or less when the tensile speed is 200 mm / min and 1.8 kgf in the vertical direction.

Further, another aspect of the present invention is a silver-like artificial leather having a grain resin layer on at least one surface of the artificial leather base material, or a suede-like artificial leather in which at least one side of the artificial leather base material is brushed. is there. Further, the elongation set rate of the silver-like artificial leather described later is preferably 20 to 50%.

In addition, another aspect of the present invention includes a fiber entanglement of nylon-based ultrafine fibers of 1.5 dtex or less and a polymer elastic body impregnated in the fiber entanglement, and has an apparent density of 0.2 to 0.5 g. By immersing the untreated artificial leather base material at / cm ³ and the untreated artificial leather base material in a treatment liquid containing benzyl alcohol, the apparent shrinkage rate is adjusted to 5 to 40%. It is a method for producing an artificial leather base material including a step of shrinking. According to such a manufacturing method, the artificial leather base material as described above can be obtained.

The step of shrinking so that the apparent shrinkage rate is 5 to 40% is a step of immersing the untreated artificial leather base material in a treatment liquid containing 10 to 300 g / L of benzyl alcohol at 90 to 110 ° C. Is preferable.

Another aspect of the present invention is a step of preparing an artificial leather base material obtained by the above-mentioned method for producing an artificial leather base material, and a grain resin on at least one surface of the artificial leather base material by a direct coating method. It is a method for producing silver-like artificial leather including a step of forming a layer.

According to the present invention, it is possible to obtain an artificial leather base material which has a high feeling of fullness and a supple texture like natural leather and can form a dense and highly smooth surface with few large voids. Further, when the grain surface resin layer is formed by using the direct coating method, an artificial leather base material can be obtained in which the resin liquid for forming the grain surface resin layer is not excessively submerged.

The artificial leather base material of the present embodiment and the artificial leather using the same will be described in detail with reference to an example of a method for producing them. In the production of the artificial leather base material of the present embodiment, first, a fiber entanglement of nylon-based ultrafine fibers (hereinafter, also simply referred to as ultrafine fibers) of 1.5 dtex or less and a polymer elastic body impregnated in the fiber entanglement are used. An untreated artificial leather base material having an apparent density of 0.2 to 0.5 g / cm ³ is produced.

In the production of fiber entanglements, first, the thermoplastic resin that constitutes the sea component of the sea-island type composite fiber that can be selectively removed and the nylon that constitutes the island component of the sea-island type composite fiber that is the resin component that forms the ultrafine fiber. A sea-island type composite fiber is obtained by melt-spinning and stretching the based resin. In addition, in this embodiment, the case where the sea-island type composite fiber is used will be described in detail, but even if the ultrafine fiber generation type fiber other than the sea-island type composite fiber is used, or without using the ultrafine fiber generation type fiber, directly. Very fine fibers may be spun.

As the sea component thermoplastic resin, a thermoplastic resin having a different solubility in a solvent or a decomposition property in a decomposing agent from the island component resin is selected. Specific examples of the thermoplastic resin constituting the sea component include polyethylene, polypropylene, polystyrene, ethylene propylene resin, ethylene vinyl acetate resin, styrene ethylene resin, and styrene acrylic resin.

A nylon-based resin is used as the thermoplastic resin, which is a resin component that forms island components and forms ultrafine fibers. Specific examples of the nylon-based resin include 6-nylon, 6,6-nylon, 10-nylon, 11-nylon, 12-nylon, 6,12-nylon and the like. These may be used alone or in combination of two or more.

As a method for producing a fiber entanglement of ultrafine fibers, for example, a sea island type composite fiber is melt-spun to produce a web, the web is entangled, and then the sea component is selectively removed from the sea island type composite fiber. Examples thereof include methods for forming ultrafine fibers. As a method for producing a web, a method of forming a long fiber web by collecting long fibers of sea-island type composite fibers spun by a spunbond method on a net without cutting them, or cutting long fibers into staples. A method of forming a short fiber web can be mentioned. Among these, the long fiber web is particularly preferable because it is excellent in fineness and fullness. In addition, the formed web may be subjected to a fusion treatment in order to impart morphological stability.

Usually, in any step from removing the sea component of the web composed of sea-island type composite fibers to forming ultrafine fibers, fiber shrinkage treatment such as entanglement treatment and heat shrinkage treatment with water vapor is performed to make the fibers dense. It is preferable to carry out a chemical treatment. As the entanglement treatment, for example, a method is used in which about 5 to 100 layers of the obtained webs are stacked and the webs are entangled using a known non-woven fabric manufacturing method such as needle punching or high-pressure water flow treatment.

The sea component of the sea-island type composite fiber can be extracted or decomposed and removed at an appropriate stage after the web is formed. By such extraction removal or decomposition removal, the sea-island type composite fiber is made into ultrafine fibers to form fiber bundle-like ultrafine fibers.

The fineness of the ultrafine fibers is 1.5 dtex or less, 0.001 to 1.2 dtex, further 0.002 to 1.0 dtex, especially 0.005 to 0.8 dtex, and in particular 0.005 to 0.5 dtex. Is preferable. If the fineness is too high, the feeling of fineness becomes insufficient, and there is a tendency that a fiber entangled body having a feeling of coarseness is obtained. Further, fibers having too low fineness are difficult to produce, and the fibers tend to be bundled without being unraveled, resulting in high rigidity of the obtained fiber entanglement.

The fiber entangled body is impregnated with a polymer elastic body in any step. The ratio of the polymer elastic body to be impregnated is preferably 5 to 25 parts by mass, more preferably 8 to 20 parts by mass with respect to 100 parts by mass of the ultrafine fibers. When the amount of the polymer elastic body is too large, the repulsive feeling becomes high and the rubber feeling increases, so that the suppleness tends to decrease. On the other hand, if the amount is too small, creases remain when bent, and the quality tends to deteriorate.

The polymer elastic body is coagulated after impregnating a fiber entangled body of ultrafine fiber-generating fibers or a fiber entangled body made into ultrafine fibers with a resin solution such as a solution of the polymer elastic body or an emulsion. By doing so, impregnation is applied. The polymer elastic body may be a porous polymer elastic body or a non-porous polymer elastic body.

Specific examples of such a polymer elastic body include polyurethane, acrylic elastic body, silicone elastic body, diene elastic body, nitrile elastic body, fluorine elastic body, polystyrene elastic body, and polyolefin elastic body. Examples include a body, a polyamide-based elastic body, and a halogen-based elastic body. These may be used alone or in combination of two or more. Among these, polyurethane is preferable because it has excellent wear resistance and mechanical properties.

Specific examples of polyurethane include polycarbonate-based polyurethane, polyester-based polyurethane, polyether-based polyurethane, polycarbonate / ether-based polyurethane, and the like.

The polymer elastic body to which the fiber entanglement or impregnation is applied may contain a pigment or may be dyed with a dye. The pigment may be fixed to the fiber entanglement with a polymer elastic body as a binder, or may be kneaded with the fibers themselves forming the fiber entanglement, but the pigment must be fixed to the fiber entanglement with a polymer elastic body. Is preferable from the viewpoint of colorability and easy color matching.

The type of pigment is not particularly limited. Specific examples thereof include organic pigments such as diketopyrrolopyrrole pigments, quinacridone pigments, and anthraquinone pigments as red to orange pigments, and inorganic pigments such as iron oxide; as yellow pigments, isoindrin pigments. Organic pigments such as pigments, quinophthalone pigments, condensed azo pigments, and azo complex pigments, and inorganic pigments such as bismus yellow and titanium yellow; as green to blue pigments, copper phthalocyanine pigments, cobalt blue, navy blue, and ultra Inorganic pigments such as marine; carbon black and the like can be mentioned as black pigments. Such pigments may be used alone or in combination of two or more in order to adjust the color to a desired color.

In this way, an untreated artificial leather base material containing a fiber entanglement of polyamide-based ultrafine fibers of 1.5 dtex or less and a polymer elastic body impregnated in the fiber entanglement is produced. Then, the obtained untreated artificial leather base material is subjected to a thickness adjustment or flattening treatment by slicing treatment or buffing treatment as necessary. In this way, the untreated artificial leather substrate is prepared.

The thickness of the untreated artificial leather base material is preferably 0.15 to 3.0 mm, more preferably about 0.3 to 2.0 mm. Further, the basis weight of the untreated artificial leather base material is preferably about 50 to 1650 g / m ² , and more preferably about 90 to 1100 g / m ² from the viewpoint of obtaining an artificial leather base material having an excellent sense of fulfillment.

The apparent density of the untreated artificial leather base material is 0.2 to 0.5 g / cm ³ , further 0.25 to 0.4 g / cm ³ , especially 0.3 to 0.4 g / cm ³ , It is preferable that the degree is such that an artificial leather base material having an excellent sense of fulfillment can be obtained.

Next, the untreated artificial leather base material is treated with a treatment liquid containing benzyl alcohol. Specifically, it is immersed in a treatment solution containing 10 to 300 g / L of benzyl alcohol at a temperature of 90 to 110 ° C. By such a treatment, the untreated artificial leather base material is shrunk so that the apparent shrinkage rate is preferably 5 to 40%, and the mechanical strength of the nylon-based ultrafine fibers is reduced to improve the suppleness.

In the method for producing an artificial leather base material of the present embodiment, the concentration of benzyl alcohol in the treatment liquid and the temperature of the treatment liquid are important. That is, the artificial leather base material of the present embodiment can be obtained by treating the untreated artificial leather base material under a predetermined concentration and temperature condition.

As the treatment liquid containing benzyl alcohol, an aqueous liquid such as an emulsion containing benzyl alcohol is preferably used. Further, the treatment liquid containing benzyl alcohol may contain an antifoaming agent, a softener in a bath, a hit inhibitor and the like. For the treatment with the treatment liquid containing benzyl alcohol, a drum dyeing machine, a normal pressure zicker dyeing machine, a high pressure zicker dyeing machine, a liquid flow dyeing machine and the like are used.

The concentration of benzyl alcohol in the treatment liquid is preferably 10 to 300 g / L, more preferably 30 to 150 g / L, and particularly preferably 50 to 100 g / L. The maximum treatment temperature of the treatment liquid containing benzyl alcohol is 80 to 110 ° C., more preferably 90 to 110 ° C., and particularly preferably 100 to 110 ° C. When the concentration of benzyl alcohol is too high or the treatment temperature is too high, the untreated artificial leather base material contracts sufficiently and tightens to improve the sense of fulfillment, but the deterioration of the ultrafine fibers causes tear strength, etc. Mechanical properties tend to decline. On the other hand, when the concentration of benzyl alcohol is too low or the treatment temperature is too low, the untreated artificial leather base material does not shrink sufficiently and becomes difficult to tighten, and there is a tendency that a desired sense of fulfillment cannot be obtained.

The treatment time of the untreated artificial leather base material with the treatment liquid depends on the treatment temperature and the concentration of benzyl alcohol, but it is preferably maintained at the maximum temperature for 5 to 180 minutes, more preferably 20 to 60 minutes. If the treatment time at the maximum temperature is less than 5 minutes, the effect of the treatment is not sufficiently obtained, and if the treatment time at the maximum temperature exceeds 180 minutes, the productivity is lowered.

Further, it is preferable to perform soaping after the treatment with the treatment liquid containing benzyl alcohol. The conditions for soaping are not particularly limited, and examples thereof include conditions for treating with a soaping solution prepared by adding an alkaline agent such as caustic soda, soda ash or sodium tripolyphosphate, a surfactant or a chelating agent to water at room temperature to about 100 ° C. Be done. Further, it is preferable to perform soaping a plurality of times. For example, a soaping solution to which an alkaline agent or a surfactant is added is used for the first soaping, and the second soaping is performed so as to treat with water only. Is preferable. Further, following the treatment with the treatment liquid containing benzyl alcohol and soaping, post-processing treatment such as dyeing may be performed as necessary.

By treating the untreated artificial leather base material with a treatment liquid containing benzyl alcohol, the untreated artificial leather base material shrinks and the voids between the fibers are reduced. It also reduces the mechanical strength of nylon-based ultrafine fibers. In this way, the untreated artificial leather base material is changed to the artificial leather base material. The apparent shrinkage rate of the untreated artificial leather base material by the treatment at this time is preferably 5 to 40%, more preferably 10 to 25%, and particularly preferably 10 to 20%. The shrinkage rate is the average value of the shrinkage rates in the vertical direction and the horizontal direction. If the apparent shrinkage rate is too low, the fiber density of the ultrafine fibers contained in the untreated artificial leather base material tends not to be sufficiently densified. On the other hand, if the apparent shrinkage rate is too high, the mechanical strength of the ultrafine fibers contained in the untreated artificial leather base material tends to be too low, and the mechanical properties such as tear strength tend to be too low.

The artificial leather base material thus obtained contains a fiber entanglement of nylon-based ultrafine fibers of 1.5 dtex or less and a polymer elastic body impregnated in the fiber entanglement, and has an apparent density of 0.3 to 0. It is 55 g / cm ³ , the ratio of 20% strength in the vertical direction / horizontal direction is 0.5 to 1.25, and the tear strength per 1 mm of thickness is 2.5 kgf / mm or more. Such an artificial leather base material has a feeling of fullness and a supple texture like natural leather, and can form an extremely smooth surface.

The thickness of the artificial leather base material is not particularly limited, but is preferably 0.1 to 3 mm, more preferably about 0.3 to 2 mm. Further, the basis weight of the artificial leather base material is preferably about 50 to 1650 g / m ² , and more preferably about 90 to 1100 g / m ² from the viewpoint of obtaining an artificial leather having an excellent sense of fulfillment.

The apparent density of the artificial leather base material is 0.3 to 0.55 g / cm ³ , further 0.35 to 0.5 g / cm ³ , and particularly 0.4 to 0.5 g / cm ^3. Is preferable from the viewpoint that an artificial leather base material having an excellent sense of fulfillment can be obtained. If the apparent density of the artificial leather base material is too low, the feeling of fulfillment tends to be insufficient, and if it is too high, the suppleness tends to decrease.

Further, the ratio of the 20% strong vertical / horizontal direction of the artificial leather base material is 0.5 to 1.25, 0.6 to 1.2, and further 0.8 to 1.2. preferable. Here, the ratio of the vertical direction / horizontal direction with 20% strength is usually measured with the traveling direction in the manufacturing process where the 20% strength is highest as the vertical direction and the direction orthogonal to the vertical direction as the horizontal direction. It is a 20% strong ratio. Since the artificial leather base material having such a 20% strong vertical / horizontal direction ratio is a homogeneous base material, it is difficult for large voids to exist on the surface.

The tear strength per 1 mm of the thickness of the artificial leather base material is 2.5 kgf / mm or more, preferably 3.0 to 8.0 kgf / mm, and more preferably 3.0 to 6.0 kgf / mm. .. Within such a range, sufficient mechanical properties for practical use can be maintained. In addition, a test piece was prepared for each artificial leather base material in an arbitrary direction, a direction rotated by 45 degrees with respect to that direction, and a direction rotated by 90 degrees with respect to that direction. The value obtained by dividing the maximum value of the measured tear strengths by the thickness is defined as the tear strength per 1 mm.

Further, in the vertical direction, the elongation rate at a tensile speed of 200 mm / min and 1.8 kgf is preferably 6.5% or less, more preferably 6.0%, and particularly preferably 5.0% or less. Here, the elongation rate in the vertical direction is the elongation rate when the traveling direction in the manufacturing process is the vertical direction and the elongation rate becomes 1.8 kgf when pulled at a tensile speed of 200 mm / min in the vertical direction.

The artificial leather base material is subjected to thickness adjustment and flattening treatment by slicing treatment or buffing treatment as necessary, kneading softening treatment, blanking softening treatment, reverse seal brushing treatment, antifouling treatment, and hydrophilization treatment. , Lubricants treatment, softener treatment, antioxidant treatment, ultraviolet absorber treatment, fluorescent agent treatment, flame retardant treatment and other finishing treatments may be performed.

Further, such an artificial leather base material is finished into a silver-like artificial leather by imparting a silver surface resin layer to the surface. Further, the suede-like artificial leather is finished by raising the fibers on the surface layer of the fiber entangled body.

As a method of forming a grain resin layer on the artificial leather base material, a film for forming the skin layer is formed on the release paper, and the resin layer is adhered to the surface of the artificial leather base material via the adhesive layer. Silver is obtained by applying a resin solution of a polymer elastic body for forming a grain surface resin layer on the surface of an artificial leather base material by a dry surface forming method or a method such as spray coating or reverse coating, and drying the resin solution. A direct coating method for forming a film of a surface resin layer is known. Of these, the direct coat method is preferable in terms of excellent productivity, but when applied to an artificial leather base material having many voids, the liquid may sink inside or the shape of the non-woven fabric may emerge on the surface. There was a drawback of doing. These drawbacks of the direct coating method can be solved by increasing the thickness of the grain resin layer, but when the thickness of the grain resin layer is increased, the texture becomes rubber-like and tends to be separated from the texture of natural leather. There is.

The artificial leather base material of the present embodiment is shrunk by treating with a treatment liquid containing benzyl alcohol to reduce voids. Therefore, it is possible to form a surface having a dense fiber density and high smoothness. Further, on such a surface, even if the direct coating method is used, the resin liquid does not easily sink, so that a grain resin layer that is not too thick can be formed.

Examples of the resin component for forming the grain surface resin layer include polyurethane, acrylic elastic body, silicone elastic body, diene elastic body, nitrile elastic body, fluorine elastic body, polystyrene elastic body, and polyolefin elastic body. Examples thereof include an elastic body, a polyamide-based elastic body, and a halogen-based elastic body. Among these, polyurethane is preferable because it has excellent wear resistance and mechanical properties. Further, the resin component for forming the grain surface resin layer may contain a colorant, an ultraviolet absorber, a surfactant, a flame retardant, an antioxidant and the like, if necessary.

The thickness of the grain resin layer is preferably 10 to 1000 μm, more preferably 50 to 300 μm. Further, the grain resin layer may have a laminated structure in which a plurality of layers such as a base coat layer, a colored layer, and a top coat layer are appropriately laminated. Further, the grain surface resin layer may have a grain formed by embossing or the like.

Further, the obtained silver-tone artificial leather preferably has an elongation set rate of 20 to 50%, more preferably 30 to 40%, as defined as follows, from the viewpoint of excellent fulfillment.
[Extended set rate]
From the obtained silver-like artificial leather, a strip sample having a length of 20 cm and a width of 2.54 cm is prepared. Then, a marked line with a distance between the marked lines of 10 cm is drawn at a position of 5 cm from both ends in the length direction of the strip sample. Then, the strip sample is hung so that the length direction is vertical, a load of 8 kgf is applied for 10 minutes, the load is removed, and the strip sample is left for 10 minutes. This operation is repeated 5 times, and the distance between the marked lines (H1) with the load applied for 10 minutes at the 5th time and the distance between the marked lines (H2) after the load is removed and left for 10 minutes are measured. The direction of progress of the manufacturing process was the vertical direction, the direction perpendicular to the vertical direction was the horizontal direction, and three strip samples in each direction were measured, and the average value of a total of six H1 and H2 was obtained. Then, using the average value of H1 and H2, the elongation set rate is calculated by the following formula.
Extension set rate (%) = [(H2-10) / (H1-10)] × 100
Further, in the case of such an extension set rate, it is preferable to obtain shoes that are easy to fit on the foot, such as natural leather, especially when silver-like artificial leather is used as shoes. If the stretch set rate is too low, it becomes difficult to fit the shape of the foot when wearing the manufactured shoes, and the wearing feeling tends to be deteriorated. Further, when the stretch set rate exceeds 20%, the silver-like artificial leather is likely to be deformed to follow the shape of the foot when the manufactured shoes are worn. If it exceeds 50%, the silver-like artificial leather tends to stretch easily over time, and a gap tends to be easily formed between the shoe and the foot.

When the untreated artificial leather base material is treated with a treatment liquid containing benzyl alcohol, the elongation set rate is 20% even under the condition of 80 to 110 ° C. if the concentration of benzyl alcohol is less than 10 g / L. When the concentration of benzyl alcohol exceeds 300 g / L, the elongation set rate tends to exceed 50%.

The artificial leather obtained in this way is preferably used as a leather-like material for shoes, clothing, gloves, bags, balls, interiors, vehicle interiors, and the like.

The present invention will be described in more detail with reference to Examples. The scope of the present invention is not limited to the examples. In the following description, "part" or "%" is based on mass unless otherwise specified.

[Example 1]
6-Nylon and polyethylene are each melted by a uniaxial extruder, and the island component is 6-nylon, the sea component is high-fluidity low-density polyethylene, and the sea component / island component ratio = 50/50. The composite fiber was melt-spun with a composite spinning nozzle. Then, the obtained yarn was drawn, crimped, and cut to obtain a staple having a cut length of 51 mm and 3.5 dtex. The obtained staples were passed through a card to form a web by a cross wrapper method, and the staples were laminated. Next, a non-woven fabric having a basis weight of 530 g / m 2 was obtained by needle punching with a needle stick density of 980 punch / cm ² .

Then, after heating the obtained non-woven fabric, the polyethylene component was melt-fixed by pressing to smooth the surface of the non-woven fabric. Then, the non-woven fabric having a smooth surface was impregnated with a 13% dimethylformamide (DMF) solution of polyester polyurethane, and then immersed in a DMF aqueous solution to solidify the polyurethane into a sponge shape. Then, polyethylene, which is a sea component of the sea-island type composite fiber, was extracted and removed with toluene at 95 ° C., and then dried to obtain an intermediate of an artificial leather base material. Then, both sides of the intermediate were buffed with 400-count sandpaper to smooth the surface, thereby obtaining an untreated artificial leather base material (a1). The untreated artificial leather base material (a1) is composed of a fiber entanglement of 0.006 dtex ultrafine fibers and polyurethane impregnated in the fiber entanglement, with an apparent density of 0.353 g / cm ³ , a grain size of 476 g / m ² , and a thickness. It was an artificial leather base material with a thickness of 1.35 mm.

On the other hand, a treatment liquid containing 60 g / L of benzyl alcohol was prepared by adding an emulsified dispersion of benzyl alcohol to water, and the treatment liquid was transferred to a drum dyeing machine. Then, after the untreated artificial leather base material (a1) is washed and relaxed, it is immersed in the treatment liquid in the tank of the drum dyeing machine, the temperature is raised from 20 ° C. to 110 ° C. in about 40 minutes, and the temperature is raised at 110 ° C. for 40 minutes. The immersion was continued. Then, it was soaped and washed twice with hot water at 80 ° C.

Then, the untreated artificial leather base material (a1) after soaping was dyed. For dyeing, a drum dyeing machine was used to perform a dyeing treatment at 95 ° C. for 60 minutes with a dye solution containing a black acid dye, followed by soaping and then a fixing treatment using synthetic tannins. Then, after drying at 100 ° C., a dyed artificial leather base material (A) was obtained by performing a finishing set. The artificial leather base material (A) thus obtained is composed of a fiber entanglement of 0.006 dtex ultrafine fibers and polyurethane impregnated in the fiber entanglement, and has an apparent density of 0.43 g / cm ³ and a grain size of 636 g. It was an artificial leather base material with a thickness of / m ² and a thickness of 1.48 mm. The ratio of 20% strength in the vertical direction / horizontal direction is 1.15, the tear strength per 1 mm of thickness in the vertical direction is 3.8 kgf / mm, and the elongation rate in the vertical direction is 5.0%. there were. The apparent shrinkage of the treatment liquid containing benzyl alcohol was 16% in the vertical direction, 11% in the horizontal direction, and 13.5% on average.

The various characteristics of the artificial leather base material were measured as follows.

(Metsuke (g / m ² ))
The measurement was performed according to JIS L1913 "General short fiber non-woven fabric test method".

(Thickness (mm) and apparent density (g / cm ³ ))
The thickness was measured according to JIS L1913 "General short fiber non-woven fabric test method", and the apparent density was calculated from this value and the basis weight value.

(20% strong)
In the direction of travel in the manufacturing process, measured at a tensile speed of 100 mm / min using a 2.5 cm x 16 cm test piece cut out from an artificial leather base material in accordance with JIS L1096 8.12.1 "Tensile strength test". The stress-strain curves of certain vertical and horizontal directions were obtained. Then, the stress at the time of 20% extension from the stress-strain curve was read, and 20% strength was obtained.

(Tearing strength)
Using a 4 cm x 10 cm test piece cut out from the obtained artificial leather base material, the artificial leather base material is pulled according to the JISL1096 8.15.1 A-1 method (single tongue) "tear strength test". The tearing strength was determined by measuring the load when tearing at a speed of 100 mm / min. The test piece was prepared in each of the vertical direction and the horizontal direction, which are the traveling directions in the manufacturing process, and measured by them. Then, the value obtained by dividing the maximum value of the tear strength in the vertical direction by the thickness was defined as the tear strength per 1 mm.

(Vertical extension rate)
According to JIS L1096, a test piece was prepared in which the traveling direction (vertical direction) of the artificial leather base material manufacturing process was the longitudinal direction, with a gripping interval of 200 mm, a gripping width of 50 mm, and a tensile speed of 200 mm / min. The elongation at 8 kgf was measured with three samples. Then, the average value thereof was taken as the elongation rate (%) when the tensile speed was 1.8 kgf at a tensile speed of 200 mm / min in the vertical direction.

(Apparent shrinkage rate)
A 300 cm x 140 cm test piece is cut out from the obtained artificial leather base material, 50 cm x 50 cm (vertical x horizontal) is marked in the center, and the dimensional changes in the vertical and horizontal directions before and after treatment with the treatment liquid are measured. did. Then, the average value of the shrinkage rates in the vertical direction and the horizontal direction was calculated.

Then, a silver-like artificial leather was produced by forming a grain surface resin layer on the artificial leather base material (A) by a direct coating method. Specifically, by applying a polyurethane solution to the surface of the artificial leather base material (A) using a reverse coater, the water absorption time when 3 cc of water droplets were dropped was flattened to such that it was 3 minutes or more. A polyurethane layer having a film thickness of 14 μm was formed by applying a resin solution for forming an epidermis layer containing a pigment and polyurethane on the surface thereof. Then, a top coat (lacquer) adjusted to 30 cp with an Iwata cup (IWATA NK-2 12s) is applied to the surface of the polyurethane layer, and a top coat with a film thickness of 5 μm is formed as a part of the skin layer to give a silver tone. Obtained artificial leather. Then, the obtained silver-like artificial leather was evaluated as follows.

(Extended set rate)
A strip sample of 20 cm in length and 2.54 cm in width was prepared from silver-like artificial leather. Then, a marked line with a distance between the marked lines of 10 cm was drawn at a position of 5 cm from both ends in the length direction of the strip sample. Then, the strip sample was hung so that the length direction was vertical, a load of 8 kgf was applied for 10 minutes, the load was removed, and the strip sample was left for 10 minutes. This operation is repeated 5 times, and the distance between the marked lines (H1: cm) after the load is applied for 10 minutes for the 5th time and the distance between the marked lines (H2: cm) after the load is removed and left for 10 minutes are measured. did. The direction of progress of the manufacturing process was the vertical direction, the direction perpendicular to the vertical direction was the horizontal direction, and three strip samples in each direction were measured, and the average value of a total of six H1 and H2 was obtained. Then, using the average value of H1 and H2, the elongation set rate was calculated by the following formula.
Extension set rate (%) = [(H2-10) / (H1-10)] × 100

(Broken grain)
The obtained silver-like artificial leather was cut into 20 × 20 cm to prepare a sample. Then, the appearance was judged according to the following criteria by bending inward with the central portion as a boundary.
A: When folded, fine and fine creases and creases with a rounded and full feeling occurred. It was also excellent in drapeability.
B: The creases were rough and deep wrinkles with large buckling, and fine creases could not be obtained, resulting in a lack of fulfillment. It was also inferior in drapeability.
C: The sense of fulfillment was extremely low.

(Repulsion)
The obtained artificial leather was cut into 20 × 20 cm to prepare a sample. Then, after grasping the artificial leather with a hand like rolling it, the state when the hand was opened and released was judged as follows.
A: Like natural leather, it retains its shape when rolled.
B: The shape when rolled was retained for a while, and then gradually recovered to the original shape.
C: The shape when rolled by the repulsive force immediately recovered to the original shape.

The above evaluation results are shown in Table 1 below.

[Examples 2 to 9 and Comparative Examples 1 to 4]
In Example 1, the artificial leather base material and silver were subjected to the same steps as in Example 1 except that the concentration of benzyl alcohol in the treatment liquid and the temperature of the treatment liquid were changed as shown in Table 1 for treatment. Obtained conditioned artificial leather. Then, it was evaluated in the same manner. The results are shown in Table 1.

[Examples 10 to 12]
6-Nylon and polyethylene are each melted by a uniaxial extruder, and the island component is 6-nylon, the sea component is high-fluidity low-density polyethylene, and the sea component / island component ratio = 50/50. The composite fiber was melt-spun with a composite spinning nozzle. Then, the sea-island type composite fiber discharged from the composite spinning nozzle was blown onto the collection net while being stretched by an air flow of 3500 m / min to obtain a long fiber web of the sea-island type composite fiber. The basis weight of the obtained long fiber web was 36 g / m ² , and the fineness of the sea-island type composite fiber was 2 dtex. This long fiber web is continuously folded at regular intervals at a folding angle of 84 degrees with respect to the length direction of the web, so that 10 layers of webs are stacked, a laminated web having a width of 210 cm and a basis weight of 360 g / m ² . Got Then, the obtained laminated web was subjected to a needle punch of 1400 punch / cm ² using a 1-barb felt needle, and further passed between heating rolls and heat-pressed to obtain a basis weight of 650 g / m ² . An entangled non-woven fabric of sea-island type composite fibers having a thickness of 1.53 mm was obtained.

Then, after impregnating the entangled non-woven fabric of the sea-island type composite fiber with an 18% DMF solution of polyester polyurethane, the polyurethane was solidified into a sponge by immersing it in a DMF aqueous solution. Then, polyethylene, which is a sea component of the sea-island type composite fiber, was extracted and removed with toluene at 95 ° C., and then dried to obtain an intermediate of an artificial leather base material containing a fiber entanglement of fiber bundles of ultrafine elongated fibers. Further, in order to improve the slipperiness between the ultrafine fibers, the intermediate was added so as to be 1.8% with respect to the artificial leather base material from which a lubricant (aqueous dispersion of silicone oil) can be obtained. .. When the morphological angle of the laminated web immediately before the entanglement treatment was 45 degrees, the morphological angle immediately after applying the oil agent was 56 degrees. Next, a heat treatment was carried out under the conditions of 2% overfeed in the vertical direction (MD), 3% widening in the horizontal direction (TD), and an atmospheric temperature of 120 ° C. Then, both sides of the intermediate were buffed with 400-count sandpaper to smooth the surface, thereby obtaining an untreated artificial leather base material (b1). The untreated artificial leather base material (b1) is composed of a fiber entanglement of 0.1 dtex ultrafine fibers and polyurethane impregnated with the fiber entanglement, with an apparent density of 0.379 g / cm ³ , and a grain size of 553 g / m 2. It was an artificial leather base material having a thickness of 1.46 mm.

An untreated artificial leather base material (b1) was used instead of the untreated artificial leather base material (a1), and the concentration of benzyl alcohol in the treatment liquid and the temperature of the treatment liquid were treated as shown in Table 2. In the subsequent steps, the same steps as in Example 1 were carried out to obtain an artificial leather base material and a silver-based artificial leather. Then, it was evaluated in the same manner. The results are shown in Table 2.

[Example 13]
6-Nylon and polyethylene are each melted by a uniaxial extruder, and the island component is 6-nylon, the sea component is high-fluidity low-density polyethylene, and the sea component / island component ratio = 50/50. The composite fiber was melt-spun with a composite spinning nozzle. Then, the sea-island type composite fiber discharged from the composite spinning nozzle was blown onto the collection net while being stretched by an air flow of 3500 m / min to obtain a long fiber web of the sea-island type composite fiber. The basis weight of the obtained long fiber web was 36 g / m ² , and the fineness of the sea-island type composite fiber was 2 dtex. This long fiber web is continuously folded at regular intervals at a folding angle of 84 degrees with respect to the length direction of the web, so that 10 layers of webs are stacked, a laminated web having a width of 210 cm and a basis weight of 360 g / m ² . Got Then, the obtained laminated web was subjected to a needle punch of 1400 punch / cm ² using a 1-barb felt needle, and further passed between heating rolls and heat-pressed to obtain a basis weight of 650 g / m ² . An entangled non-woven fabric of sea-island type composite fibers having a thickness of 1.53 mm was obtained.

Then, after impregnating the entangled non-woven fabric of the sea-island type composite fiber with an 18% DMF solution of polyester polyurethane, the polyurethane was solidified into a sponge by immersing it in a DMF aqueous solution. Then, polyethylene, which is a sea component of the sea-island type composite fiber, was extracted and removed with toluene at 95 ° C., and then dried to obtain an intermediate of an artificial leather base material containing a fiber entanglement of fiber bundles of ultrafine elongated fibers. Further, in order to improve the slipperiness between the ultrafine fibers, the intermediate was added so as to be 1.8% with respect to the artificial leather base material from which a lubricant (aqueous dispersion of silicone oil) can be obtained. .. When the morphological angle of the laminated web immediately before the entanglement treatment was 45 degrees, the morphological angle immediately after applying the oil agent was 56 degrees. Next, a heat treatment was carried out under the conditions of 2% overfeed in the vertical direction (MD), 3% widening in the horizontal direction (TD), and an atmospheric temperature of 120 ° C. Then, both sides of the intermediate were buffed with 400-count sandpaper to smooth the surface, thereby obtaining an untreated artificial leather base material (c1). The untreated artificial leather base material (c1) is composed of a fiber entanglement of 0.2 dtex ultrafine fibers and polyurethane impregnated with the fiber entanglement, and has an apparent density of 0.36 g / cm ³ and a grain size of 450 g / m ^2. It was an artificial leather base material having a thickness of 1.25 mm.

An untreated artificial leather base material (c1) was used instead of the untreated artificial leather base material (a1), and the concentration of benzyl alcohol in the treatment liquid and the temperature of the treatment liquid were treated as shown in Table 3. In the subsequent steps, the same steps as in Example 1 were carried out to obtain an artificial leather base material and a silver-based artificial leather. Then, it was evaluated in the same manner. The results are shown in Table 3.

The artificial leather of the present invention is used as a substitute material for natural leather for shoes, clothing, gloves, bags, balls, interiors, vehicle applications, and the like.

Claims (8)

It contains a fiber entangled body of nylon-based ultrafine fibers of 1.5 dtex or less and a polymer elastic body impregnated with the fiber entangled body.
The apparent density is 0.3 to 0.55 g / cm ³ ,
The 20% strong vertical / horizontal ratio is 0.5-1.25.
An artificial leather base material having a tear strength of 2.5 kgf / mm or more per 1 mm of thickness. The artificial leather base material according to claim 1, wherein the elongation rate at a tensile speed of 200 mm / min and 1.8 kgf in the vertical direction is 6.5% or less. The artificial leather base material according to claim 1 or 2, wherein a grain resin layer having a direct coat formed on at least one surface of the artificial leather base material according to claim 1 or 2 is provided. A silver-like artificial leather in which a grain resin layer is laminated on at least one surface of the artificial leather base material according to any one of claims 1 to 3. The silver-like artificial leather according to claim 4, wherein the elongation set rate specified as follows is 20 to 50%.
[Extended set rate]
Create a strip sample with a length of 20 cm and a width of 2.54 cm. Then, a marked line with a distance between the marked lines of 10 cm is drawn at a position of 5 cm from both ends in the length direction of the strip sample. Then, the strip sample is hung so that the length direction is vertical, a load of 8 kgf is applied for 10 minutes, the load is removed, and the strip sample is left for 10 minutes. This operation is repeated 5 times, and the distance between the marked lines (H1) after the load is applied for 10 minutes for the 5th time and the distance between the marked lines (H2) after the load is removed and left for 10 minutes are measured. The direction of progress of the manufacturing process is the vertical direction, the direction perpendicular to the vertical direction is the horizontal direction, and three strip samples in each direction are measured, and the average value of a total of six H1 and H2 is obtained. Then, using the average value of H1 and H2, the elongation set rate is calculated by the following formula.
Extension set rate (%) = ((H2-10) / (H1-10)] × 100 A suede-like artificial leather in which at least one surface of the artificial leather base material according to any one of claims 1 to 3 is brushed. An untreated artificial leather base containing a fiber entanglement of nylon-based ultrafine fibers of 1.5 dtex or less and a polymer elastic body impregnated in the fiber entanglement, and having an apparent density of 0.2 to 0.5 g / cm ^3. a step of preparing the wood,
The untreated artificial leather substrate was immersed in the treatment liquid of 90 to 110 ° C. in aqueous benzyl alcohol of 10 to 300 g / L, process for producing an artificial leather substrate comprising the more Engineering performing soaping, the. A step of preparing an artificial leather base material obtained by the method for producing an artificial leather base material according to claim 7, and a step of preparing the artificial leather base material.
A method for producing a silver-like artificial leather, comprising a step of forming a grain resin layer on at least one surface of the artificial leather base material by a direct coating method.