JP2002339262A - Method for producing synthetic leather and the resultant synthetic leather - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a synthetic leather having stable processability and soft touch feeling and also high abrasion resistance, and to provide a method for producing the synthetic leather by coating method. SOLUTION: This method for producing a synthetic leather is characterized by comprising the steps of subjecting a fibrous base material to the treatment of including 20-100 wt.% of water thereinto and coating the resultant hydrous fibrous base material with a polyurethane resin solution or polyureaurethane resin solution followed by drying to form a resin coating film on the fibrous base material. The objective synthetic leather obtained by this method is thus provided.

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 synthetic leather and synthetic leather, and more particularly to a method for streamlining the production process and reducing the production process cost as compared with conventional synthetic leather. The present invention relates to a method for producing synthetic leather excellent in quality and synthetic leather. The synthetic leather obtained by the present invention is suitable for all uses of synthetic leather such as interior materials for automobiles, seat materials for motorcycles, furniture, curtains, clothing, gloves, shoes and the like.

[0002]

2. Description of the Related Art Conventional methods for producing synthetic leather include:
Create a polyurethane resin or polyurea urethane resin film on release paper in advance, apply an adhesive to this,
There are a dry method in which a film and a fiber base material are bonded, and a coating method in which a polyurethane resin or a polyureaurethane resin solution is directly applied to a cloth.

In addition, a polyurethane resin or a polyureaurethane resin is applied to a fiber base material, a microporous layer is formed by coagulation in water to form a wet base, and a polyurethane resin or a polyurethane resin previously formed on release paper in the same manner as in the dry method. There is a wet method of bonding the skin using a polyurea urethane resin film and a heat laminating or adhesive, but the wet method usually requires time for coagulation in water, and the amount of the polyurethane resin or the polyurea urethane resin solution used also increases. For,
As manufacturing costs rise, it is difficult to supply products at low cost.

[0004] The dry method and the coating method have a simplified production process as compared with the wet method, and are useful for suppressing production costs and supplying inexpensive products. However, synthetic leather by a dry method requires release paper to form a skin layer, and an adhesive is used to bond a film formed on the release paper. For this adhesive, a mixture of a polyurethane resin solution and an isocyanate-based crosslinking agent is usually used, and it is necessary to crosslink the adhesive by aging in a temperature atmosphere of about 40 ° C. for 24 to 48 hours. For this reason, the equipment and cost for keeping the temperature warm, and the time required for aging are long, and a certain number of days are required for the delivery date of the product.

[0005] On the other hand, an adhesive which is extremely fast in crosslinking and does not require aging has been developed. In this case, however, the crosslinking reaction is so rapid that the resin solution before coating thickens in a short time.
At the present time, equipment that can be applied simultaneously with mixing is required, and it is currently difficult to use the equipment except for limited manufacturers.

In the case of directly coating a fiber base material with a polyurethane resin or a polyurea urethane resin solution, the production cost can be reduced without using a release paper and an adhesive, but the resin solution permeates the fiber base material. There are restrictions such as selection of a fiber base material which is likely to occur, has a smooth surface and a high fiber density, and sets a high viscosity of a resin solution to be used. For example, for a base cloth of dry synthetic leather, a brushed cloth is often used because of its excellent properties such as flexibility, voluminous feel and tear strength, but a polyurethane resin or a polyureaurethane resin solution is applied to a raised surface such as a brushed cloth. In the case of coating, the texture after drying becomes hard because the resin solution easily permeates, and the value of the product is reduced, and the product is significantly unvalued.

[0007]

SUMMARY OF THE INVENTION In the present invention, when a fiber base material is coated with a polyurethane resin or a polyureaurethane resin solution, for example, the resin solution easily penetrates like a brushed cloth. Even on fiber base materials that cannot be made with synthetic leather by the coating method,
An object of the present invention is to provide a synthetic leather having stable workability and a soft texture, and a method of manufacturing the synthetic leather by preventing the resin solution from soaking, thereby enabling the production of synthetic leather by a coating method.

[0008]

The above object is achieved by the present invention described below. That is, in the present invention, the fiber base is subjected to a treatment for containing 20 to 100% by weight of water, and the water-containing fiber base is subjected to a polyurethane resin or a polyurea urethane resin (hereinafter, both are also simply referred to as “polyurethane resin”). A) a method of producing a synthetic leather, which comprises coating a solution and drying to form a resin film on a fiber base material;
And a synthetic leather obtained by the method.

According to the present invention, as a result of extensive studies to prevent the penetration of the polyurethane resin solution into the fiber base material and to obtain a synthetic leather having stable workability and a soft texture, the fiber base material contains water. By applying the treatment and applying the polyurethane resin solution in a state of being hydrated and drying, a synthetic leather having a soft texture in which the resin solution is prevented from seeping into the fiber base material can be obtained. If the surface lacks smoothness in this state,
A method of performing embossing by a conventionally known method and smoothing the surface and performing a surface treatment as necessary, or a method of applying a resin solution after embossing repeatedly and performing a surface treatment as necessary to obtain a smooth surface design Synthetic leather having excellent properties can be obtained, and the above problem can be solved.

Further, the synthetic leather according to the present invention has a cross-sectional structure in which the resin film and the fiber base material are in close contact with each other and have few bubbles, as shown in FIG. Compared with the conventional dry-processed synthetic leather, which has many air bubbles between the fiber base material and the adhesive layer shown in FIG. Synthetic leather with excellent properties can be obtained. Further, according to the present invention, by using the fiber base material used by the dry method, and manufacturing a synthetic leather similar to the dry method by the coating method, the cost of the release paper is omitted, and the aging of the adhesive is performed. Eliminating the process makes it possible to provide synthetic leather with reduced manufacturing costs, such as a reduction in the manufacturing process time and equipment required for aging.

[0011]

Next, the present invention will be described in more detail with reference to preferred embodiments. The fiber base material used in the present invention may be a material conventionally used in the production of synthetic leather, for example, synthetic fibers such as polyester, polyamide, and polyacrylonitrile; natural fibers such as cotton and hemp; rayon; Single or blended fibers such as regenerated fibers and the like, or conventionally known nonwoven fabrics may be mentioned. These may be raised on both sides or one side, or may be used on both sides.

[0012] In the method of treating the fiber base with water, the fiber base is immersed in water, and the water content is 20 to 10% based on the weight of the fiber base.
Squeeze with a mangle or the like so that it becomes 0% by weight. The higher the water content, the higher the effect of preventing the penetration of the resin solution.However, if the water content is too high, the adhesiveness between the fiber base material and the polyurethane resin is reduced, or water seeps out of the fiber base material during coating, and the resin solution is removed. The water content is more preferably set to about 60 to 90% by weight because streaks are generated in the coating because the coating cannot be applied uniformly. At this time, in order to impart functionalities such as water repellency and flame retardancy to the fibrous base material, various additives such as a water repellent, a flame retardant, and an antistatic agent are added to water containing water to obtain a synthetic material. Various functions can be imparted to leather.

In the present invention, the resin to be coated on the fiber base material is a polyurethane resin solution used in the production of synthetic leather or has both a urethane bond and a urea bond.
In a so-called polyurea urethane resin, a known long-chain diol and an isocyanate compound and, if necessary, a chain extender, diol, diamine, hydrazide and the like are optionally combined and reacted in a non-solvent or a solvent by a known and commonly used method. can get. The compounds used are not particularly limited, but only typical ones are exemplified.

As the long-chain polyol, polycarbonate diols, polyether diols, polyester diols and the like can be used alone or as a mixture or a copolymer.

Representative examples of polycarbonate diols include diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol,
A reaction product of a diol such as 1,4-cyclohexanedimethanol with a dialkyl carbonate such as dimethylene carbonate or diethylene carbonate or a cyclic carbonate such as ethylene carbonate is exemplified.

Typical examples of polyether diols include compounds obtained by ring-opening polymerization of a single or a mixture of three or four-membered ether compounds such as ethylene oxide, propylene oxide, and tetrahydrofuran. Is mentioned.

Representative examples of the polyester diol include:
Dibasic acids (eg, succinic acid, glutaric acid, adipic acid, sebacic acid, fumaric acid, maleic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, tartaric acid,
Oxalic acid, malonic acid, pimelic acid, suberic acid, curtaconic acid, azelaic acid, etc.) or their anhydrides and glycols (eg, ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, 1, 2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl -1,5-pentanediol,
1,8-octanediol, 1,9-nonanediol,
Aliphatic glycols such as neopentyl glycol; 1,4
Alicyclic glycols such as cyclohexanedimethanol;
Aromatic glycols such as xylylene glycol; C1 to C
18, alkyldialkanolamines such as alkyldiethanolamine, etc.)
For example, polyethylene adipate, polybutylene adipate, condensed polyester polyols such as polyhexamethylene adipate, or polylactone diol, polycaprolactone diol, polymethyl valerolactone obtained by ring-opening polymerization of lactone using the diols and the like as an initiator Lactone-based polyester diols such as diols.

In addition, polyacryl diol, polyolefin diol, polybutadiene diol, oil-modified diol, and the like can be used. Although the molecular weight of the long-chain polyol is not particularly limited, the weight-average molecular weight (measured by GPC) is in the range of 300 to 10,000.
00-5000 is appropriate and preferred.

Representative examples of the isocyanate compound include:
1,6-hexamethylene diisocyanate (HDI),
2,2,4-trimethylhexamethylene diisocyanate, lysine methyl ester diisocyanate, methylene diisocyanate, isopropylene diisocyanate,
Lysine diisocyanate, 1,5-octylene diisocyanate, aliphatic isocyanate of dimer acid diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, isophorone diisocyanate (IPDI),
Hydrogenated tolylene diisocyanate, methylcyclohexane diisocyanate, alicyclic isocyanate of isopropylidene dicyclohexyl-4,4'-diisocyanate, 2,4- or 2,6-tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthylene diisocyanate, xylylene diisocyanate (XDI), triphenylmethane triisocyanate, tris (4-phenyl isocyanate) thiophosphate, tolidine diisocyanate, p-phenylene diisocyanate, diphenyl ether diisocyanate, diphenyl sulfone diisocyanate Neat aromatic isocyanates, MDI, TD
Adducts obtained by reacting I, HDI, XDI, IPDI, etc. with dihydric or trihydric alcohols, HDI and IPDI
Etc., uretdione such as TDI, TD
And isocyanurates such as HDI and IPDI.

Representative examples of the diol compound used as a chain extender include ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, 1,2-propanediol, 1,3-propanediol, and 1,2. -Butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8
Aliphatic glycols such as -octanediol, 1,9-nonanediol and neopentyl glycol; alicyclic glycols such as bishydroxymethylcyclohexane and cyclohexane-1,4-diol; and aromatic glycols such as xylylene glycol. Can be

Representative examples of the diamine compound used as a chain extender include ethylenediamine, diaminopropane,
Diaminobutane, hexamethylenediamine, trimethylhexamethylenediamine, diaminopropylamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, N-
Aminoethylpiperazine, bis-aminopropylpiperazine, polyoxyethylenediamine, polyoxypropylenediamine, polyoxyethylenepropylenediamine, polyoxyethylenetriamine, polyoxypropylenetriamine, isophoronediamine, 1,3-bisaminomethylcyclohexane, 4,4 -Diaminocyclohexylmethane, diaminobenzene, m-xylenediamine.

Representative examples of the hydrazide compound used as a chain extender include carbodihydrazide, adipic hydrazide, sebacic dihydrazide, dodecane diacid dihydrazide, and isophthalic dihydrazide.
In addition, alkanolamines such as monoethanolamine and diethanolamine or polyhydric alcohols such as glycerin and trimethylolpropane can be used. The use of a polyhydric alcohol or isocyanate compound having three or more functional groups reduces the solubility of the resulting resin and the fluidity of the resin solution, and significantly impairs coating suitability. It is preferable to use the compound of

In addition, a silicone-modified polyurethane or polyureaurethane resin or an acrylic-modified polyurethane or polyureaurethane resin can be used alone or in combination, and the chemical structure is not particularly limited.

The organic solvent for dissolving the resin can be added at any stage, such as at the start of the reaction of the resin raw material, during the reaction, or after the reaction. As the solvent to be added, a conventionally known solvent typified by dimethylformamide (DMF) can be used. However, in order to improve the drying property after application of the resin solution, methanol, ethanol, isopropyl alcohol (IPA), toluene (TOL), It is preferable to use a solvent having a boiling point lower than that of water, such as methyl ethyl ketone (MEK) and ethyl acetate, alone or as a mixture of two or more. This is because, when the resin solution is coated on the water-containing treated fiber substrate and dried, the solvent in the resin solution can be scattered earlier than the water of the fiber substrate, and furthermore, the permeation of the resin solution is prevented. And a smoother film can be formed.

These resins are usually provided with a coloring agent such as a pigment, and various additives such as a cross-linking agent, a cross-linking accelerator, a flame retardant, an antioxidant, a hydrolysis-resistant agent, silica, a fine polymer powder, and a filler. In addition, other known resins such as a nitrocellulose resin, an acrylic resin, and an acrylonitrile-butadiene resin can be added.

The resin solution to be used for coating may be added with the above-mentioned resin solution and additives such as the above-mentioned coloring agents such as pigments, flame retardants, thickeners, etc. in accordance with the intended use. Adjust the viscosity to use. As a diluting solvent at this time, a solvent having a boiling point lower than that of water, such as methanol, ethanol, isopropyl alcohol, toluene, methyl ethyl ketone, and ethyl acetate, is used to improve the drying property after application of the resin solution. It is preferable that the pressure be at least 30 dPa · S or more in order to prevent intrusion. Such a resin solution can be obtained and used under a trade name (manufactured by Dainichi Seika Kogyo Co., Ltd.) such as “Rezamin” as described in Examples.

As a method for coating the resin solution, a method using a knife coater, a roll coater, a comma coater or the like on a water-containing fiber base material can be used. The clearance at this time is adjusted in consideration of the unevenness of the fiber base material, and is preferably in the range of 100 μm to 1000 μm. At this time, a smoother synthetic leather can be obtained by imparting smoothness to the fiber base material application surface using a hot roll or the like before or after the water-containing treatment of the fiber base material.

The drying conditions after the application of the resin solution are not particularly limited.
By gradually increasing the drying temperature from a temperature of 00 ° C. or less (preferably 50 to 80 ° C.), the solvent can be scattered while the fiber base material is kept in a water-containing state, and the resin solution is more prevented from seeping. A coating can be easily formed on a fiber base material. Subsequently, the solvent and water are completely scattered at about 120 ° C. to obtain a film (silver layer) on the fiber base material. The thickness of the resin film to be formed when this is generally about 10~150μm about.

The synthetic leather obtained in the above manufacturing process can be used as a product as it is. For example, it is used for a portion where a resin layer is hidden, such as clothing and backing material of a bag, and has a waterproof function and a reinforcing fiber. Functions and the like can be provided. To further impart functionality, the obtained silver surface layer can be overcoated with a resin solution, and the first and second or third layer resin solutions may be the same or different. For example, it is possible to improve the wear resistance of the resin film by forming a silver surface layer using a non-silicone modified polyurea urethane resin solution for the lower layer and applying the silicone modified polyurea urethane resin solution to the outermost skin layer. it can. In this case, the thickness of the outermost layer is about 5 to 100 μm. Subsequently, a conventionally known embossing method is used to give a smoothness to the silver surface layer to narrow down the surface, or to adjust the gloss by a surface treatment method using a gravure printer, to prevent blocking, to have a smooth surface. And synthetic leather having excellent design properties can be obtained. Incidentally, the resin solution to be repeatedly applied may be applied after embossing, and in this case, in order to prevent re-dissolution of the surface smoothed by embossing,
It is preferable to minimize the DMF content of the resin solution to be repeatedly applied.

[0030]

EXAMPLES The present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited by these examples. In the examples and comparative examples, “parts” or “%” are all based on weight unless otherwise specified. Example 1 Resazin NE-8851 [manufactured by Dainichi Seika Kogyo Co., Ltd., 100% modulus, 6 MPa, non-yellowing type polycarbonate-based polyureaurethane resin solution (solvent-based IPA / TOL = 50 /
50 (weight ratio, the same applies hereinafter), solid content 25%)] 100
To 5 parts by weight of a mixed solvent (IPA) / TOL = 50/50 (weight ratio, the same applies hereinafter) and stirred. Next, 10 parts of Seika Seven BS-780 (S) BLACK (manufactured by Dainichi Seika Kogyo Co., Ltd .: black colorant) was added and stirred, and the solution viscosity was 200 dPa.
-Resin solution 1 of S / 20 ° C was prepared.

Next, a thickness of 550 μm and a basis weight of 165 g /
Moss with brushed tricot m ² (after Moss peeling, the thickness 300
μm, a basis weight of 87 g / m ² ) are immersed in water and squeezed with a mangle so that the weight ratio of the fiber base material to water becomes 100: 80 (pickup 80%). Immediately use a roll coater,
The resin solution 1 is coated on the raised surface with a clearance of 500 μm. After drying at 70 ° C. for 3 minutes, drying at 130 ° C. for 5 minutes, and then embossing with an embossing roll containing embossing heated to 155 ° C., the synthetic leather of the present invention was obtained.
The thickness of the resin film of this synthetic leather is about 100 μm,
The synthetic leather had good surface smoothness, flexibility and adhesiveness.

Example 2 A synthetic leather of the present invention was obtained by the same processing method as in Example 1 except that the pickup was treated with 60% of water. The obtained synthetic leather was a synthetic leather having a degree of feeling of texture that was slightly more than that of the synthetic leather obtained in Example 1, and was almost the same as the other synthetic leathers with good surface smoothness and adhesiveness.

Example 3 Rezamine NES-8852 [manufactured by Dainichi Seika Kogyo Co., Ltd., 100
% Modulus 6MPa silicone-modified non-yellowing polycarbonate-based polyureaurethane resin solution (solvent-based IP
(A / TOL = 50/50, solid content: 25%)] 100 parts of a mixed solvent of IPA / TOL = 50/50 is added and stirred. Next, Seika Seven BS-780 (S) BLACK
10 parts (manufactured by Dainichi Seika Kogyo Co., Ltd .: black colorant) were added and stirred to prepare a resin solution 2 having a solution viscosity of 200 dPa · S / 20 ° C.

Next, water is immersed in the tricot used in Example 1 and squeezed with a mangle so that the pickup becomes 80%. Immediately, using a roll coater, the resin solution 1 is coated on the raised surface with a clearance of 350 μm.
After drying at 70 ° C. for 3 minutes, drying is performed at 130 ° C. for 2 minutes. Subsequently, the resin solution 2 was applied repeatedly with a clearance of 150 μm,
After drying at 70 ° C. for 2 minutes, it is dried at 130 ° C. for about 10 minutes. Next, embossing was performed with a grained embossing roll heated to 155 ° C. to obtain a synthetic artificial leather having excellent surface smoothness, a smooth surface, a soft texture, and excellent wear resistance. The thickness of the first resin film was about 70 μm, and the thickness of the outermost film was about 30 μm.

Example 4 Resamine NE-8851 [manufactured by Dainichi Seika Kogyo: 100% modulus, 6 MPa, non-yellowing type polycarbonate-based polyureaurethane resin solution (solvent-based IPA / TOL = 50 /
50, solid content 25%)] IPA / TOL = 5 in 100 parts
30 parts of a 0/50 mixture is added and stirred. Next, 10 parts of Seika Seven BS-780 (S) BLACK (manufactured by Dainichi Seika Kogyo Co., Ltd .: black colorant) was added and stirred, and the solution viscosity was 30.
A resin solution 3 of dPa · S / 20 ° C. was prepared.

Next, water is immersed in a raising cloth (polyester-rayon) having a thickness of 850 μm on one side, and squeezed with a mangle so that the pickup becomes 80%. Immediately using a roll coater, resin solution 1 with a clearance of 350μ
m. After drying at 70 ° C for 3 minutes, 130 ° C
Dry for 2 minutes. Next, embossing is performed with a embossing roll containing embossing heated to 155 ° C., followed by applying the resin solution 3 again with a clearance of 150 μm, drying at 70 ° C. for 2 minutes, and drying at 130 ° C. for about 10 minutes to obtain a surface lubricity. Synthetic leather with excellent surface resistance, smooth surface, soft texture and good abrasion resistance was obtained. The thickness of the first resin film is about 70 μm, and the thickness of the outermost film is about 30 μm.
Met.

COMPARATIVE EXAMPLE 1 The synthetic leather of the comparative example was prepared in the same manner as in Example 1 except that the resin solution 1 was applied to the tricot used in Example 1 and the process of hydrating the tricot was omitted. Produced. As a result, at the same time as the application of the resin solution 1, the resin solution 1 began to permeate into the tricot, resulting in an extremely hard synthetic leather with fibers appearing on the surface.

Comparative Example 2 A synthetic leather of a comparative example was prepared by the same processing method as in Example 1 except that the pickup was subjected to a water-containing treatment at 120%. As a result, at the start of coating, the mixture 1
Was not applied on the tricot, and a phenomenon of slipping on the tricot was observed. For this reason, the obtained synthetic leather had good flexibility, but lacked processing stability in which the resin was exfoliated in the portion where the liquid mixture slipped.

COMPARATIVE EXAMPLE 3 The resin solution 1 was applied to the brushed cloth used in Example 4, and the process of synthesizing the comparative example was carried out in the same manner as in Example 1 except that the step of humidifying the brushed cloth was omitted. Created leather. As a result, at the same time as the application of the resin solution 1, the resin solution 1 began to seep into the raising cloth, and the raised leather appeared on the surface, resulting in an extremely hard synthetic leather with severe irregularities.

Comparative Example 4 Resamine NE-8851 [manufactured by Dainichi Seika Kogyo Co., Ltd .: 100% modulus, 6 MPa, non-yellowing type polycarbonate-based polyureaurethane resin solution (solvent-based IPA / TOL = 50 /
50, 25% solids)] and add 15 parts of DMF to 100 parts and stir. Next, Seika Seven BS-780 (S) BLA
Add 10 parts of CK (colorant), stir and add solution viscosity 60
A resin solution 4 of dPa · S / 20 ° C. is prepared. 100 parts of Rezamin UD-8351 (a two-pack polycarbonate polyurethane resin solution manufactured by Dainichi Seika Kogyo) and Rezamin UD
-10 parts of a cross-linking agent (manufactured by Dainichi Seika Kogyo, cross-linking agent) and 5 parts of Rezamine UD-103 accelerator (manufactured by Dainichi Seika Kogyo, cross-linking accelerator)
And 30 parts of MEK and 10 parts of DMF were added and stirred to prepare a resin solution 5 having a solution viscosity of 170 dPa · S / 20 ° C.

Next, release paper (EV130, manufactured by Lintec Corporation)
After drying the resin solution 4 on the TPSG R-8), the thickness is 3
It is applied to a thickness of 0 μm and dried at 100 ° C. for 2 minutes. Next, the resin solution 5 was overlaid and applied so that the thickness after drying was 70 μm, so that the film thickness after drying was equal to that of Example 4 and Comparative Example 3. Immediately by using a laminator, the lamination is applied to the raised surface of the raised cloth used in Example 4 and Comparative Example 3 (lamination clearance 50).
% (50% of the thickness of the cloth and brushed cloth)]. After drying at 120 ° C. for 3 minutes and aging at 40 ° C. for 48 hours, the release paper was peeled off to obtain a smooth and soft synthetic leather by a dry method.

Table 1 below shows the evaluation results of the texture, abrasion resistance and appearance of the synthetic leathers obtained in each of the above Examples and Comparative Examples.

<Measurement and Evaluation Methods> The texture was evaluated by touch based on the following evaluation criteria. 5: Extremely excellent flexibility. 4: Excellent flexibility. 3: Somewhat hard. 2: Hard. 1: Extremely hard.

2. Abrasion resistance test method JIS L-0823 (friction tester for color fastness test)
Using a Gakushin type abrasion tester specified in JIS L
-No. 6 canvas of 0823, width 30mm, length 250mm
And fix it on the sample table of the tester so that wrinkles do not occur. Next, each of the synthetic leathers of the example and the comparative example was cut into a size of 20 mm in width and 50 mm in length, and this test piece was firmly attached to a friction element. The pressing load of the friction element is 1000 gf, the stroke is 100 mm, and the speed is 3
The test was performed at 0 reciprocations / minute, and the surface state of the test specimen during 3000 reciprocations was visually observed and evaluated according to the following evaluation criteria. ；: No change is observed on the outermost surface of the synthetic leather. Δ: A state in which the resin on the outermost surface of the synthetic leather has been shaved by abrasion. ×: A state in which the resin on the outermost surface of the synthetic leather was shaved and a raised cloth appeared.

[0045]

As described above, in the conventional coating of a fiber base material with a polyurethane or polyureaurethane resin solution, a fiber base having a high fiber density and a smooth base material is selected in order to prevent penetration of the resin solution. Despite restrictions such as thin coating of high-viscosity resin solution, according to the present invention, by impregnating the fiber base material with water, it is possible to prevent the resin solution from penetrating and expand the width of the usable fiber base material. At the same time, it was possible to obtain synthetic leather having a soft texture.

For example, a brushed cloth easily penetrates a resin solution, and therefore prevents the resin solution from penetrating even on a fiber base material on which synthetic leather cannot be produced by a conventional coating method. Production of synthetic leather by the coating method was made possible, and synthetic leather excellent in abrasion resistance having stable workability and a soft texture was obtained.

Further, since the synthetic leather similar to the dry method can be obtained by the coating method according to the present invention, the cost for the release paper can be reduced, and the adhesive which requires the aging step can be eliminated, thereby significantly reducing the production time. The equipment required for shortening and aging can be eliminated, and an economic effect of reducing manufacturing costs can be obtained.

[Brief description of the drawings]

FIG. 1 is a scanning electron micrograph of a cross section illustrating an example of the synthetic leather of the present invention.

FIG. 2 is a scanning electron micrograph of a cross section illustrating synthetic leather by a conventional dry method.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Isao Kondo 1-7-6 Nihombashi Bakurocho, Chuo-ku, Tokyo Dai-Nisseika Industry Co., Ltd. F-term (reference) 4F055 AA03 BA13 DA02 EA04 EA05 EA06 EA24 FA16 GA02 HA06 4L033 AA02 AA03 AA05 AA07 AA08 AB07 AC11 AC15 CA36 CA50 CA59

Claims (5)

[Claims] 1. A fiber base material is subjected to a treatment for containing 20 to 100% by weight of water, a water-containing fiber base material is coated with a polyurethane resin or a polyureaurethane resin solution, and dried to form a resin film. A method for producing synthetic leather, wherein the method is formed on a substrate. 2. The method for producing synthetic leather according to claim 1, wherein the obtained synthetic leather is further subjected to embossing and / or surface treatment. 3. The method for producing a synthetic leather according to claim 1, wherein the coating of the resin solution is performed twice or more to provide two or more resin coatings. 4. A resin solution to be coated for the first time,
The method for producing synthetic leather according to claim 3, wherein the non-silicone-modified polyurethane resin or polyurea urethane resin solution is used, and the resin solution to be coated last is a silicone-modified polyurethane resin or polyurea urethane resin solution. 5. A synthetic leather excellent in abrasion resistance, obtained by the method according to any one of claims 1 to 4.