US3908060A

US3908060A - Artificial leather and method of preparation

Info

Publication number: US3908060A
Authority: US
Inventors: Kaoru Okazaki; Akira Higuchi; Naoki Imaeda
Original assignee: Toray Industries Inc
Current assignee: Toray Industries Inc
Priority date: 1972-10-17
Filing date: 1974-03-18
Publication date: 1975-09-23
Anticipated expiration: 1992-09-23

Abstract

Artificial leather is composed of four layers: a fibrous substrate, a urethane polymer layer (III) containing finely divided inorganic particles, a thinner urethane polymer layer (II) consisting of at least about 80% by weight of polyurethane, and a coating layer (I) consisting of at least about 80% by weight of polyurethane.

Description

United States Patent [1 1 Okazaki et al.

[4 1 Sept. 23, 1975 ARTIFICIAL LEATHER AND METHOD OF PREPARATION Inventors: Kaoru Okazaki; Akira Higuchi;

Naoki Imaeda, all of Otsu, Japan Assignee:

Filed: Mar. 18, 1974 Appl. No.: 451,915

Related US. Application Data Division of Ser. No. 298,449, Oct. 17, 1972, Pat. No. 3,841.897.

US. Cl. 428/246; 428/303; 428/304; 428/323; 428/334; 428/337; 428/903, 428/904; 427/373; 427/412 Int. Cl. 844D l/l4 Field of Search 117/76 T, 76 R, 161 KP, 117/47 H; 161/89,158, 170,190, DIG. 2

Toray Industries, Inc., Tokyo, Japan- [56] References Cited UNITED STATES PATENTS 3,481,767 12/1969 Craven et al 117/76 T 3,537,871 11/1970 Kaneko 117/76 T 3,632,417 1/1972 Brasen 117/76 T Primary Examiner-William D. Martin Assistant Examiner-.lanyce A. Bell [57] ABSTRACT 25 Claims, 3 Drawing Figures US Patent Sept. 23,1975 3,908,060

35cm 3cm 35cm F'ig. 3

ARTIFICIAL LEATHER AND METHOD OF PREPARATION This is a division of application Ser. No. 298,449, filed Oct. 17, 1972, and now U.S. Pat. No. 3,841,897.

This invention is concerned with artificial leather and a method for its preparation. More particularly, this invention relates to an artificial leather which, when bent or flexed, forms creases having an appearance which is just the same as that of natural leather, and even German Box Calf, which is a very high class of natural upper leather. The creases are equal to those of the leather without any processing such as finishing, embossing, transfer-coating, etc. These creases are formed easily and reversibly when the leather is bent, and disappear casily and reversibly when the leather is flattened out again.

PRIOR ART In general, to obtain artificial leather, a fibrous substrate has been prepared from a non-woven fabric, or a woven or knitted fabric impregnated with an impregnating composition. On the surface of this substrate a microporous polymeric coating layer is applied to provide a composite structure having two layers. It is said that peculiar properties of artificial leather such as water vapor permeability. water vapor absorption, surface smoothness, appearance and feeling, etc. are obtained owing to the microporous structure mentioned above, and the mechanical properties of artificial leather depend mainly upon the structure of the fibrous substrate. The ease of forming creases, and the appearance of the creases obtained by bending or flexing, depend directly on the nature of the microporous coating layer and indirectly related to the structure of the fibrous substrate.

Hitherto, studies of microporous'structures and the relation between the structure of the microporous coating'layer and the properties of leather have been reported, but little is known with respect to the appearance of creases of artificial leather as compared to natural leather.

For instance. in British patent 1,133,606 mention is made concerning a homogeneous and microporous artificial leather having good water vapor permeability and water vapor absorption, and the fibrous substrate composing one part of the artificial leather was obtained by impregnating a fibrous material with a composition containing synthetic polymer, a definite amount of non-solvent for the synthetic polymer. For each 100 parts of synthetic polymer there were added from 5 to 80 parts of an inorganic compound having a mean particle diameter of 40 2.000 mu, which is virtually insoluble in the solvent and non-solvent for the synthetic polymer. The artificial leather prepared by using the above substrate is superior with respect to water vapor permeability and water; vapor absorption, but the appearance of creases and the ease of their formation were the same as in artificial. leathers hitherto obtained.

Although prior studies on artificial leather have been made. there has been almost no valuable achievement relating to the appearance of creases in artificial leather to simulate creases in natural leather. particularly German Box Calf. for example, as a result of bending or flexing.

Accordingly. it is an object of this invention to procal and physical properties such as water vapor permeability. tear and scuff resistance, tensile strength and elongation, etc., as compared to artificial leather hitherto obtained, and (b) good appearance of creases as compared to natural leather, particularly German Box Calf, for example, upon bending or flexing. Another vide an artificial leather having excellent (a) mechaniobject of this invention is to provide a manufacturing method which is advantageous in industrial production.

The foregoing and other objects of this invention can achieved by preparing artificial leather consisting of following coating layers (I), (II), (III), and a fibrous substrate, as will now be described in detail.

The coating layer (I) has a thickness of about 0.001 to 0.1 mm and a 20 /1 modulus of about 5 to 100 kg/cm and consists of a polymer composition containing at least about wt% of polyurethane.

The coating layer (II), obtained by the wetcoagulating method, has a thickness of about 0.01 to 0.3 mm, consists of polymer composition which contains 0 to 50 parts by weight of inorganic particles for each parts by weight of polymer (coagulation stabilizer is excluded from this polymer this definition is used through to the end). These inorganic particles have a mean particle diameter of about 0.03 to 5.0 micron, and are insoluble in water, and the polymer consists of at least about 80 wt% of polyurethane.

Coating layer (III), obtained by the wet-coagulating method, has a thickness of about 0.1 to 3.0 mm, consists of polymer composition which contains about 50 to 300 parts by weight of inorganic particles for each 100 parts by weight of polymer (coagulation stabilizer is excluded from this polymer this definition is used through to the end), and these inorganic particles have a mean particle of about 0.03 to 5.0 micron, and are insoluble in water, and the polymer consists of at least about 60 wt% of polyurethane.

In describing the relative proportions in coating layers (II) and (111) above, we have excluded any protecting agent from our consideration, but it is to be understood that an agent is usually added. This understanding will be followed throughout this specification, and in the claims. Z

The role of the agglutination protecting agent is to protect the microporous structure from changing to a non-porous structure.

The fibrous substrate has a thickness of about 0.3 to 3.0 mm and consists of at least a polymer and a fabric, which may be non-woven, knitted or woven. Coating layers (1), (II). (III) and the fibrous substrate are joined to one another in order, by the method to be described in detail hereinafter.

DRAWINGS In FIG. 1 an example of the cross-sections of the arti ficial leather of this invention is illustrated. In this FIG., (I) is the coating layer (1), (2) is the coating layer (II), (3) is the coating layer (III) and (4) is the fibrous substrate composed of a fabric impregnated with a polymer composition. The multi-coating layer consists of coating layers (1), (II), and (Ill).

FIG. 2 shows the measurement of 6, the creaseforming angle referred to in tests of the artificial leather 5.

FIG. 3 is a diagrammatic illustration of a part of a method for testing flexibility resistance of artificial leather.

The polymer contained in coating layer (I) and (II) used in this invention is composed of (a) polyurethane or (b) more than about 80 wt% of polyurethane and less than about 20 wt% of a polymer selected from the group consisting of polyvinyl chloride, polyvinylidene chloride. polyvinyl acetate, polyacrylic acid, alkylpolyacrylate. polymethacrylic acid, alkylpolymethacrylate, and copolymers consisting of at least of one of the above mentioned polymer segments, and mixtures of the above mentioned polymers.

The polymer contained in coating layer (Ill) used in this invention is composed of (c) polyurethane or (d) more than about 60 wt% of polyurethane and less than about 40 wt% of such polymers are mentioned in (b).

The polyurethane contained in coating layers (I), (II) and (III) used in this invention is (c) the product of reaction of polymer diols, di-isocyanates and diamines and/or lower molecular diols, wherein the polymer diol is selected from the group consisting of poly-etherdiols, poly-ester-diols and poly-ether-ester-diols.

The polymer contained in the impregnating composition used in this invention is as follows: (f) the polyurethane of (c) or (g) a polymer selected from the group consisting of polyvinyl chloride, copolymers of vinyl chloride and vinyl acetate, polyacrylic acid and its csters, and polymethacrylic acid and its esters, or (h) mixtures of more than about 50 wt% of polyurethane of (e) and less than about 50 wt% of the polymers mentioned in (g).

In polymer compositions for coating layers (I), (II), (III) and impregnating compositions, such addition compounds as pigments, dyes, anti-oxidants, pulp powders, fiber powders, etc. may be added.

The inorganic compounds contained in the above coating compositions (II) and (III), used in this invention, are as follows: calcium carbonate, titanium oxide, zinc oxide, kaolinite, carbonates (such as zinc carbonate, cadmium carbonate, copper carbonate, barium carbonate, etc.), oxides (such as chromium oxide, aluminum oxide, antimony oxide, cobalt oxide, tin oxide, iron oxide, etc.), sulfates (such as calcium sulfate, barium sulfate, etc.), phosphates (such as zinc phosphate, aluminium phosphate, calcium monohydrogen phosphate, ferrous phosphate, barium phosphate, etc.), silicates (such as cobalt silicate, magnesium silicate, potassium alumino silicate, kaolin, etc.) and mixtures of at least two of the above mentioned inorganic compounds.

Small amounts of impurities in inorganic compounds may be tolerated, so far as they do not disturb the objects of this invention. Particularly preferable inorganic compounds used in this invention are calcium carbonate, titanium oxide, zinc oxide and kaolinite.

The inorganic compounds for coating layers (II) and (Ill) used in this invention, must be insoluble in water and organic solvents, so that said inorganic compounds do not dissolve out of the coating layers (II) and (III). However, some substance in coating layer (II) and (III) must dissolve during the process of coating polymer composition (I) on the surface of coating layer (II). This causes the surface of coating layer (II) to become rough, and as a result of this process, creases are formed when the artificial leather thus obtained is bent or flexed.

Considering the cause of the formation of creases as above mentioned, the amount ofinorganic compounds, and the mean particle diameter of the inorganic compounds, are very important in order to obtain various kinds of creases with precision control.

The satisfactory range of the mean particle diameter of said inorganic compounds in coating layers (II) and (III) is about 0.03 to 5.0 micron, more satisfactory about 0.10 to 3.0 micron, and most satisfactory about 0.5 to 2.0 micron. In the case of a diameter larger than about 5.0 micron, the appearance of creases is no longer that of natural leather, and the state of dispersion of inorganic compounds in polymer composition for coating layer, flexibility resistance and scuff resistance become worse, and suitable physical properties and homogeneous structure of the leather cannot be obtained. In the case of a diameter of smaller than about 0.03 micron, the appearance of creases is not that of natural leather, and water vapor permeability and softness become worse. This will be confirmed in a detailed explanation in describing the following experiments. They show the criticality of the above mentioned ranges of mean particle diameter.

The satisfactory range of the amount of inorganic compounds in coating layer (III) is about 50 to 300 parts by weight for each parts by weight of polymer in the coating layer, more satisfactory about 80 to 200 parts, and most satisfactory about to parts. In the case of an amount of more than 300 parts in the coating layer (III), the mechanical properties of coating layer (III), such as tensile strength, elongation, tear and scuff resistance, etc., become worse, and the durability of the artificial leather also becomes worse. In the case of an amount of less than about 50 parts in the coating layer (III), the appearance of creases is not that of natural leather, and the appearance and feel are similar to those of rubber, and the properties and performance of the artificial leather in this case are those of artificial leather hitherto obtained.

The satisfactory range of thickness of coating layer (III) is about O.l to 3.0 mm, more satifactory about 0.3 to 2.0 mm, and most satisfactory about 0.5 to 1.0 mm. In to case of a thickness of coating layer (Ill) larger than about 3.0 mm, and comparatively less inorganic compounds in the coating layer (III) at the same time, the properties of artificial leather obtained are similar to those of rubber. In the case of a thickness of coating layer (III) larger than about 3.0 mm and comparatively more inorganic compounds in coating layer (III) at the same time, the mechanical properties of the coating layer and the artificial leather become worse. In the case of a thickness of coating layer (III) smaller than about 0.1 mm, the smoothness of the artificial leather become worse and the appearance of creases in the artificial leather obtained is not that of natural leather. A detailed explanation follows.

A satisfactory range of amounts of inorganic compounds in coating layer (II) is about 0 to 50 parts by weight for each 100 parts by weight of polymer in coating layer (II), more satisfactory about 0 to 20 parts, and the most satisfactory none at all. In the case of an amount more than 50 parts in the coating layer (II), the appearance of creases of artificial leather obtained is not that of natural leather. A detailed explanation follows.

A satisfactory range of thickness of coating layer (II) is about 0.01 to 0.3 mm, more satisfactory about 0.03 to 0.25 mm, and the most satisfactory about 0.05 to 0.2 mm. The detailed explanation appears in the following reports of experiments.

Coating layer (I) is prepared by a dry-coagulating method. Coating layer (I) is coated on coating layer II) and dried to remove solvent. The satisfactory range of thickness of coating layer (I) is about 0.001 to 0.1 mm, more satisfactory about 0.003 to 0.05 mm, and the most satisfactory about 0.005 to 0.02 mm. And the satisfactory range of 20% modulus of coating layer (I) is about 5 to I00 kglcm more satisfactory about to 70 kg/cm and the most satisfactory about to 50 kg/cm The method of the measurement of modulus is described hereinafter. In the case of a thickness of coating layer of smaller than 0.001 mm, the color and luster of the artificial leather is unsatisfactory, and creases cannot be formed, and scuff resistance decreases. In the case of a thickness of coating layer (I) larger than 0.3 mm, the appearance of creases and the feeling and appearance of the artificial leather obtained are not those of natural leather (the appearance of creases becomes too small), and water vapor permeability and flexibility resistance become worse, and the touch of the artificial leather becomes hard. In the case of a 20% modulus of coating layer (I) larger than 100 kg/cm the appearance of creases of artificial leather obtained is not that of natural leather, and the ease of forming creases, the ease in shoemaking, scuff resistance and flexibility resistance become worse. In the case of a 20% modulus of coating layer smaller than 5 kg/cm the appearance of creases of artificial leather obtained is not that of natural leather, the touch of artificial leather is like rubber, and the ease of forming creases decreases. A detailed explanation appears in the following experiments.

Coating layer (II) and (III) are prepared by a wetcoagulating method, and the detailed method of preparation of coating layer (II) and (III) is described hereinaftter. In this invention coating layers (II) and (III) can be prepared from a polymer composition excluding nonsolvents such as water. But when the polymer composition is used as a coating layer immediately after the polymer composition has been prepared, a small amount of non-solvent such as water in the polymer composition may be permitted.

One of the characteristics of this invention is that the artificial leather of this invention has a multi-layer structure composed of coating layers (I), (II) and (III). This multi-layer structure with a fibrous substrate brings about the appearance of the creases like that of natural leather, particularly German Box Calf.

The satisfactory range of thickness of the multi-layer coating (I), (II) and (III) of this invention is about 0.1 to 3.6 mm, more satisfactory about 0.3 to 2.0 mm. and the most satisfactoryabout 0.5 to 1.5 mm. In the case ofa thickness of the' multi-layer oflarger than about 3.6 mm, the appearance and feel of the artificial leather obtained are not like those of natural leather. In the case of a thickness of the multi-layer of less than about 0.1 mm, the appearance of creases of the artificial leather obtained is not that of natural leather.

The apparent density of coating layer (III) ,is larger than that of coating layer (II). A satisfactory range of the apparent density difference between coating layer (III) and (II) is about 0.05 to 0.8 g/cm, more satisfactory about 0.07 to 0.6 g/cm", and the most satisfactory about 0.08 to 0.4 g/cm In the case of an apparent density difference of more than 0.8 g/cm or less than 0.05 g/cm between coating layer (III) and (II), the appearance of the creases and the feel and appearance of the artificial leather obtained are not like those of natural leather. and the softness, the draping properties, the flexibility resistance, the ease in shoemaking and the ease of forming creases of the artificial leather decreasess. Aa detailed explanation appears hereinafter.

The relation of value of PU concentration in the polymer to the physical properties of artificial leather is shown in the detailed reports of experiments hereinafter.

The easeof forming creases is expressed by the crease-forming angle described in the following method of measurement, see FIG. 2. When the leather is bent top-coat-side (surface) in, in the shape of V, creases of the leather are observed at the bottom of the Vvalley. A larger crease-forming angle means it was easier to form creases. Therefore, the satisfactory range of the'crease-forming angle of the artificial leather obtain'ed is more than an approximately 40 angle, more satisfactory more than an approximately 60 angle, andthe most satisfactory more than approximately an angle. The crease-forming angle of German Box Calf, known as the highest class of natural upper leather, is about a 60 angle.

The fibrous substrate of this invention is prepared as follows. A well known fibrous web is needle-punched and impregnated with a polymer composition containing a polymer such as polyurethane and adding agent, and then we't-coagulated. In this process it is better that the surface of fibrous substrate be treated to flatten the fibers in order to obtain good artificial leather of this invention having a large value of flexibility resistance. It is satisfactory to use fibers of 0.01 to 1.0 denier, because the value of flexibility resistance of the artificial leather of this invention using the fibrous substrate,

composed of ultra fine fiber bundles as one of the components, in which a denier of each fiber is 0.01 to 1.0, is larger than that of the artificial leather obtained from fibers of ordinary denier. When using this ultra fine fiber to obtain good or better appearance and feel of the artificial leather, a satisfactory thickness of the fibrous substrate is about 0.3 to 3.0 mm, and more satisfactory about 0.5' to 1.5 mm.

The satisfactory range of the viscosities of dimethyl formamide solution with 25 wt% of polyurethane used in the coating layer (I) and the impregnating composition are about 50 to 3,000 poises at 20C, more satisfactory about to 1,500 poises, and the most satisfactory about 300 to 800 poises, And the satisfactory range of viscosities of dimethyl formamide solution with 25 wt% of polyurethane used in coating layers (II) and (III) are about 200 to 5,000 poises, more satisfactory about 500 to 3,000 poises and the most satisfactory about 800 to 2,000 poises, all measured at 20 C. A detailed explanation is provided hereinafter.

A satisfactory value of flexibility resistance of the artificial leather of this invention is more than about 10 X l0 times, more satisfactory more than about 15 X 10 times, and the most satisfactory more than about 20 X 10 times. Shoes made of artificial leather having less than 10 X 10 times of flexibility resistance are unsatisfactory, because cracks on the shoe surface arise easily. Therefore the above mentioned range of flexibility resistance is desirable.

A satisfactory range of water vapor permeability of the artificial leather of this invention is more than about 3 mg/cm hr., more satisfactory more than about 5 mg/cm hr., and the most satisfactory more than about 8 mg/cm hr. It is unsatisfactory to use artificial leather having less than 3 mg/cm hr. of water vapor permeability, because shoes made from the artificial leather tend to moisten the feet in ordinary use.

The following steps are used in the method of the artificial leather of this invention.

Step (1) The coating composition (II) for coating layer (II) is uniformly coated on a release support such as plastic film, glass plate, steel plate, or paper, so as to attain a thickness of about 0.01 to 0.3 mm of the coating layer (II) consisting of the coating composition (II).

Step 2 The coating composition (III) for coating layer (III) is uniformly coated on the coating layer (II) in Step (1 so as to attain a thickness of about 0.1 to 3.0 mm of the coating layer (III) consisting of the coating composition (III).

Step (3) On the other hand, the non-woven, or woven or knitted fabric is impregnated with an impregnating composition and then coagulated by immersing in a liquid which is a non-solvent for the polymer. The product of this step is immersed in a solution composed of nonsolvent and solvent for the polymer in the impregnating composition. In this way the wet-treated fibrous subfactory, and the other properties of the product, such as water vapor permeability, softness, repulsive elasticity, ease in shoemaking, wearing comfort, etc. are very poor. This other alternate method is that the material obtained in Step (I) to (2) is dried, which makes the material nonporous, and meanwhile the wet fibrous substrate in Step (3) is also dried, and on the surface of dried coating layer (III) an adhesive agent is coated, and with this the above dried fibrous substrate is joined,

10 and then on the dried coating layer (II) thus obtained,

the coating composition (I) is coated according to Step (6).

As mentioned above, it is preferable to adopt selected conditions and processes in order to obtain the artificial leather of this invention.

There are the following methods instead of Step (5). Namely, (a) the solvent which is contained in the coating layer (II), (III) and wet-fibrous substrate is extracted and washed, and the release support is stripped from the coating layer (II), and then dried, and (b) the strate is obtained. This is then applied to the surface of characteristic in method the coating layer (III) obtained in Step (2), and pressed lightly.

Step (4) The material obtained in Step (3) is immersed and coagulated in a coagulating liquid for a definite time at a definite temperature, to obtain a microporous structure of coating layer (II) and (III), and to unite the coating (II) and (III) with the fibrous substrate.

Step (5) The release support is stripped from the surface of the coating layer (II), and the solvent which is contained in the coating layer (II), (III) and wet-fibrous substrate is extracted and washed and then dried.

Step (6) The coating composition (1) for coating layer (I) is coated on the surface of the coating layer (II) so as to attain 0.001 to 0.1 mm in thickness of the coating layer (I), and then dried.

However, in contrast to this invention, an artificial leather obtained by the following alternative method has no crease on the surface at all, and the properties such as the flexibility resistance (3 X 10 times), the scuff resistance (300 g), the heat resistance (105 C), the surface smoothness, the color and luster of the surface and so on, become worse extremely. This alternative method is that the coating composition (I) of Step (6), instead of the coating composition (II) of Step (I) is coated on the release support, and then the coating composition (II) of Step (I) is coated on the coating layer (I) and then the coating composition (III) of Step (2) is coated on this, and then the treatment of Steps (3) to (5) is carried out in order.

The case of forming creases in the artificial leather obtained by another alternate method is very unsatis- The method of Step (5), however, can be preferable industrially to either method (a) or (b), because the extracting and washing times are shortened to less than half .of that in (a) or (b), the productive capacity increases more, the equipment is simpler and proper equipment will be able to resolve the problem of shrinkage.

The measurements of the values of physical properties in this invention are described as follows:

I. The thickness of coating layers This value is measured from a microphotograph of the cross-section of each coating layer.

2. Water vapor permeability (WVP)" This value is measured by the Calcium Chloride-cup method which is defined by Japanese Industrial Standard (JIS) K-6549, which measurement comprises setting a circular sample having an area of 28.3 cm on a measuring cup including 10 g of solid calcium chloride inside, sealing tiightly with melted paraffin which solidifies immediately, and maintaining for 4 hours in an atmosphere of i0.5 C and i 5 percent of relative humidity.

The weights of the cup containing the sample at the initial time and after 4 hours are measured, and then water vapor permeability is calculated by the following equation:

(weight of scaled cup after maintaining for 4 hours at 40 C and 90% RH.)

ple by using the sample size and thickness. The difference of the apparent density (apparent density difference) among layers is obtained as follows.

By the wet-coagulating method each mono-coating layer is prepared individually from the corresponding composition, corresponding to each layer in the multicoating layer, and the apparent density of each layer is measured by the above mentioned method and the apparent density difference is calculated. The apparent density is the average value of 10 samples.

4. 20% modulus This value is defined as the stress at 20% elongation expressed as kg/cm and it may be by a measure of the softness, whose measurement comprises maintaining the sample having a size of 2 cm X 13 cm for at least 24 hours in an atmosphere of 20 C and 65% R. H, applying the sample to a tensile testing apparatus, measuring at the condition of a pulling speed of 10 cm/min, a chart speed of l cm/min (test length of 10 cm and test width of 2 cm) and reading the stress at 20% elongation from the load-elongation curve thus obtained on the chart. For example, in the case of a dry coagulating coating layer (I), a mixture of 100 parts of DMF solution with 25 wt% polyurethane and 20 parts of carbon black dispersion of 18% by weight is coated on a polyethylene terephthalate film at a thickness of 2.0 mm and dried for 1 hour at 100 C. The resulting dry film is cut into pieces (above mentioned size) and the 20% modulus is measured under the above conditions.

5. Flexibility resistance (De Mattia Flex Test resistance) This value is defined as flexibility resistance measured by De Mattia Flex Tester whose measurement comprises folding the sample (4 X 10 cm) into two and flexing the folded sample several times in the fingers, as shown in FIG. 3, applying the sample to the De Mattia Tester to attain a test length of 3 cm and to attain an extension of 25% at the maximum amplitude, and flexing the sample at 18,000 times per hour. The flexibility resistance is expressed as the number of times until a surface crack develops on the sample. This test is more severe than that of the so-called Nikka Flex Tester observed at a low temperature (5 C), because the latter is a non-tension test, so the value of flexibility resistance measured by the De Mattia Test is lower than that measured by the Nikka Flex Tester. For examaple, in the case of side leather, the value obtained by use of the De Mattia Flex Tester is 400,000 times, but that by the Nikka Flex Tester is 1,500,000 times. De Mattia Flex Test resistance is abbreviated as DM resistance." DM resistance is expressed as an average of five samples.

6. Appearance of creases This value is expressed by the comparison with the appearance of creases in German Box Calf. This comprises bending the leather in such a way that the top coating is the inside, and evaluating the appearance of creases in comparison with that of German Box Calf by observing the length, the width, the depth and the direction of the creases. The creases of German Box Calf are qualitatively small and relatively shallow, and appear in all directions. If necessary, a photograph of creases may be used as the judgment reference.

7. Crease-forming angle This value is defined as 0, the angle of bending is shown in FIG. 2. It is defined as the angle of bending when creases appear clearly. 6 is the crease-forming angle and is also a measure of the ease of forming creases. A larger angle 0 means that the leather forms creases more easily.

8. Scuff (scratch) resistance This value is defined as the lowest load (grams) on the following needle which hurts the surface of a sample (5 X 5 cm) cemented to the regular position of the standard Clemence Scratch Resistance Tester. The head of the needle which contacts the sample has a diameter of 1 mm.

9. Heat resistance This value is defined as the softening point of the coating layer measured -by a penetrometer.

this specification, various abbreviations have been and will hereinafter be resorted to for the sake of clarity and brevity. These abbreviations are as follows:

Table of Abbreviations Exp. Experiment Comp. Comparison C.C. Coating composition C.L. Coating layer PU 25%/DMF soln DMF solution with 25 wt% polyurethane CB DMF dispersion with 15 wt% carbon black cone concentration PVC Polyvinyl chloride DOP Dioctyl phthalate CaCO Calcium carbonate A. Density Diff. Apparent density difference .R. Flexibility resistance W.V.P. Water vapor permeability App. of crease Appearance of crease C.F.Z. Crease-forming angle B.V. dye DMF solution with ID wt% black violet dye A-sol A-solution B-sol B-solution H.R. Heat resistance S.R. Scuff resistance Feel. 8L App. Feeling and appearance Thick. Thickness A.L. Artificial leather St. of Disp. of CaCO; State of dispersion of CaCO; Sur. Sm. Surface smoothness Eas. in Shoemak. Ease in shoemaking Fit. to foot Foot fitting characteristics NOTE: Part(s) used in the following description means part(s) by weight unless specifically designated otherwise.

EXPERIMENT l A. Preparation of non-woven fabric 40 parts of Nylon-6 staple fibers, of 3 denier and having a length of 51 mm, and parts of polyethylene terephthalate staple fiber of 5 denier and having a length of 51 mm, were respectively opened and then mixed. The mixed staple fiber was treated in crosslapping equipment to obtain a web and then was needlepunched to obtain a non-woven fabric. This non-woven fabric was heat pressed with a calender roll to obtain a non-woven fabric having a unit area weight of 200 g/m and a thickness of 0.8 mm.

B. Preparation of impregnating composition C. Preparation of coating composition According to the combination component and the combination amount in Table 1, each component was mixed to obtain coating composition (I), (I1) and (III).

Coating Composition (1): PU, main component as polymer, carbon black (CB) as black pigment made by poises of viscosity at 20 C. Coating layer (I) is prepared from coating composition (1).

Coating Composition (11): According to Table 1, each component was mixed to 6btain the A-solution and the B-solution. And the Asolution was added to the PU-DMF (25:75 by weight) solution, and then the B-solution was added to the above mixture and then stirred. Thus the coating composition was obtained. The viscosity of the coating composition (11) was 700 poises at 20 C. Coating layer (II) was prepared from coating composition (11).

Coating Composition (111): According to Table 1, each component was mixed to obtain the A-solution and the B-solution. The A-solution was added to the PU-DMF (:75 by weight) solution, and then the B- solution was added to the above mixture and stirred, and then about 150 parts of calcium carbonate per 100 parts of total polymer was added to the above mixture. Thus coating composition (III) was obtained. The viscosity of coating composition (III) was 1,300 poises at 20 C. Coating layer (111) was prepared from coating composition (III).

The definition of mer) is as follows:

(PU concentration)/( total poly- This definition is used throughout this specification. Each (PU concentration)/(total polymer) is 100.00 wt%, 80.01 wt%, 49.99 wt% and 30.00 wt% in Experiment [-1, I-2, Comparison I-1 and I-2 respectively.

D. Preparation ofartificial leather Non-woven fabric which was heat pressed and immersed in the above obtained impregnating composition, was squeezed in a mangle to obtain a non-woven fabric having 100 parts of impregnating composition for 100 parts of non-woven fabric, and then was immersed in water to coagulate the PU. Then this impregnated sheet was immersed in the mixed solution of DMF and water (:30 by weight) and was again squeezed in a mangle to obtain a wet-treated fibrous substrate having 100 parts of the above mixed solution per 100 parts of non-woven fabric.

Meanwhile, coating composition (11) in Table l was coated at a thickness of 0.5 mm polyethylene terephthalate film with a reverse roll coater and the coating composition (III) in Table l was coated at a thickness of 1.5 mm on the above layer of 0.5 mm in thickness with a doctor knife coater. On this layer from the above coating composition (11) and (III) the above obtained wet-treated fibrous substrate was put immediately and pressed lightly, then immersed in water to coagulate. Then this sheet material was washed with hot water of C for 30 mins, then washed with water at room temperature, and then dried at 120 C for 30 mins.

Next the polyethylene terephthalate film was stripped from the above sheet material, then coating composition (1) in Table I was coated on the surface of coating layer (11) which was contacted with a polyethylene terephthalate film with a gravure roll (roll mesh number: 180. depth: 46 microns) and finally dried. This gravure roll coating was repeated 5 times in all. A mu1ticoating layer composed of the coating layers (III), (II), (I) and the fibrous substrate were united to obtain artificial leather of this invention. The combi- (PU concemmfion) (PU Gone) 40 nation component and its amount corresponding to the (owl pmymcr) (mm polymer) coating layer (1), (II) and (III) are shown on Table 1. A n The properties of thls artificial leather are shown in PU other polymer X (WI/l Table 2 Table I (Exp. I)

Combination component and its amount for Coating Composition (1), (11). (111) C.C. (1) Exp I C.C. (11) Exp I C.C. (III) Exp 14 Exp 1'2 Com. I-1 Corn. 1-2

PU 25% DMF soln 28.38 PU 25% DMF soln 66.40 PU 25% DMF soln 54.22 43.38 27.11 16. 27 CB 28.38 A Coagulation 2.16 A Coagulation 1.76 1.41 0.88 0.55

soln stabilizer soln stabilizer B.V. Dye soln 0.68 DMF toluene (3/1) 42.56 DMF 27.78 DMF 20.70 21.92 22.74 23.28 B PVC 0.00 PVC 0 2.71 6.78 9.49 DOP 0.00 B DOP 0 1.36 3.39 4.74 soln DMF 0.00 soln DMF 0 6.09 16.26 23.04 CB 2.50 CB 2.04 2.04 2.04 2.04 CaCO; 0.00 CaCO 20.33 20.33 20.33 20.33 PU conc PU conc PU conc rota] polymer (wt%) 100.00 total polymer (wt%) 100.00 total p y (wt%) 100.00 80.01 49.99 30.00 CaCO; CaCO CaCO, total polymer X 0.00 total polymer X 100 0.00 mm] Polymer X 100 149.98 149.98 149.95 149.95

CaCO; mean particle diameter is 1.4 micron PU concentration/ total polymer of Coating Composition (111) and properties of the artificial leather Exp [-1 Exp 1-2 Comp l-l Comp [-2 PU conc total polymer of CC. (111) V I PU (PU+PVC) X 100 (wt%) 100.00 80.00 49.99 30.00 thickness C.L. (1) (mm) 0.008 0.008 0.008 0.008

C.L. (ll) (mm) 0.20 0.20 0.20 0.20 CL. (111) (mm) 0.70 0.68 0.62 0.55 leather (mm) 1.708 1.688 1.628 1.558 A. Density Diff. between C.L.(l) and C.L.(ll) (g/cm) 0.12 0.15 0.39 0.47 modulus of C.L. (l) (kg/cm) 24.75 24.75 24.75 24.75 F.R. (X 10) 43.3 40.5 8.2 1.6 W.V.P. (mg/cmlhr) 15.5 12.8 3.1 1.9 softness C) O A x softness (20 C) O x xx App. of Creases x xx C.F.A. (degree) 95 95 45 20 C.L.(l) coating layer (1) appearance just the same as that of German Box Calf (the highest grade of natural leather) 0 appearance just the same as Calf (higher grade of natural leather) A appearance just the same as Kip (middle grade of natural leather) x appearance is the same as side leather (lower grade of natural leather) xx no crease formed This definition is used throughout this specification. softness more soft 0 soft A slightly soft x not soft This definition is also used throughout this specification.

EXPERIMENT II Four kinds of artificial leather were prepared under the same conditions and using the same methods as Experiment 1, except that the combination component andthe amount of its coating composition (11) were changed as shown in Table 3. And coating composition ([11) in Experiment l-l was used as coating composition (Ill). The relation of coating composition (11) to the properties of artificial leather is shown in Table 3.

EXPERIMENT 111 Four kinds of artificial leather were prepared under the same conditions and using the same methods as Experiment 1, except that the combination component and the amount of its coating composition (1) were changed as shown in Table A. And coating composition (Ill) in Experiment l-l was used as coating composition (Ill). The result is shown in Table 4.

EXPERIMENT IV Table 3 (Exp. 11)

Combination component and amount of coating composition (11) and properties of artificial leather product Expll-l Expl1-2 Compll-l Compll-2 PU 25% DMF soln 66.40 53.12 33.20 19.92 A Coagulation stabilizer 2.16 1.73 1.08 0.65 sol DMF 27.78 22.16 13.89 8.33 8 PVC 0 3.32 8.30 11.62

DOP 0 1.66 4.15 5.81 sol DMF 0 14.58 36.30 50.82

CB 2.50 2.50 2.50 2.50 CaCO 0 0 0 0 PU conc total polymer. (C.C. (11), wt%) 100.00 80.00 50.00 30.00

CaCO PU PVC X 0 0 0 0 App. of Crease x xx C.F.A. (degrees) 98 84 40 20 ER. (X10 times) 43.5 39.5 7.5 1.0 W.V.P. (mg/cm hr.) 15.3 10.5 5.1 1.5 softness O A x Combination component and amount of coating composition (I) Explll-l Explll-Z Complll-l Comp1l1-2 PU 25% DMF soln 28.38 22.75 14.19 8.51 PVC 0.00 1.42 3.55 4.97 DOP 0.00 0.71 1.78 2.48 DMF 0.00 14.24 35.70 49.98 CB 28.38 24.12 17.74 13.48 B.V. dye 0.68 0.58 0.43 0.32 DMF toluene (3/1) 42.56 36.18 26.61 20.22 My; 100 80 02 49 98 29 98 tom! polymer of C.C. (1) (wt%) App of Crease x xx C.F.A. 95 88 42 HR. (C) 250 230 120 70 F.R. (X 10 times) 45.5 38.2 15.7 0.3 S.R. (g) 1500 1300 800 500 Feel and App x xx Table 5 (Exp. IV)

Amount of CaCO; in C. C. (111) and properties of artificial leather product Comp IV-l Exp 1V-1 Exp 1V-2 Exp IV-3 Exp 1V-4 Exp 1V-5 Exp 1V-6 Comp 1V-2 parts of CaCO; per 100 parts of polymer in C.C. (I11) 50 80 120 160 200 300 400 thick. ofC.L. (1) (mm) 0.008 0.008 0.008 0.008 0.008 0.008 0.008 0.008 thick. of C.L. (11) (mm) 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 thick. of C.L. (111) (mm) 0.51 0.55 0.60 0.69 0.70 0.70 0.73 0.75 thick. of A.L. (mm) 1.418 1.458 1.508 1.598 1.608 1.608 1.638 1.658 St. of Disp. of CaCO, 0 O 0 x A.Density Diff (C.L.(l1).(1l|) 0.01 0.06 0.08 0.12 0.16 0.20 0.24 0.29

(gl m) 20% modulus of C.L.(I) (kg/cm) 24.80 24.80 24.80 24.80 24.80 24.80 24.80 24.80 App. of Crease x O Q O x C.F.A. (degree) 20 65 80 105 1 10 85 80 50 F.R. (X 10 times) 49.1 45.0 43.7 45.5 48.0 43.0 37.8 10.0 W.V,P. (mg/cm hr.) 3.3 5.0 10.2 15.5 15.5 16.0 17.6 18.0 softness x A O O x Sur. Srn. A O 0 O x Eas. in Shoemak. x O O 0 o x Fit to foot x A O (0) x St. Disp. of CaCO Eas. in Shoemak. Sur. Sm. Foot fitting properties @z better better @z better better 0: good 0: good 0: good 0: good A: bad A: bad A: bad A: bad

x worse x worse x worse it worse EXPERIMENT v mer were used in coating composition (II). And coating According to Experiment I, 4 kinds of artificial leather were prepared except that in coating composition (11) 0, 40, 70 and 100 parts ofinorganic compound per 100 parts of total polymer were used respectively. And coating composition (11]) in Experiment 1-1 was used as coating composition (111). In order to obtain a good appearance of creases, as large crease-forming angle, as strong flexibility resistance and as good water vapor permeability as in Experiment 1V. to use from 0 to parts of the above mentioned inorganic compound were satisfactory, more satisfactory from 0 to 20 parts and the most satisfactory 0 part.

EXPERIMENT V1 According to Experiment I, 8 kinds of artificial leather were prepared except that in coating composition (11) and (111), 0.01, 0.03, 0.10, 0.50. 2.00, 3.00, 5.00 and 10.00 micron of mean particle diameter of inorganic compound particle were used, and that 20 parts of inorganic compound for 100 parts of all polycomposition (III) in Experiment [-1 was used as coating composition (Ill). The properties of the artificial leather thus obtained and the state of dispersion of inorganic compound in the coating composition (II) and (III) are shown in Table 6.

EXPERIMENT V11 Titanium oxide, zinc oxide, kaolinite and zinc carbonate instead of calcium carbonate in Experiment I were mixed into coating composition (II) and (111) respectively as shown in Table 7, and 4 kinds of artificial leather were prepared according to Experiment 1 except that in coating composition (11) 20 parts of inorganic compound for parts of total polymer were used. And as for coating composition (111) the same combination amount as in Experiment [-1 was used. The result is shown in Table 7, which shows that these 4 kinds of inorganic compounds above mentioned and calcium carbonate used in Experiment 1 to V1 are particularly superior.

Mean particle diameter of CaCO, in C.C. (11) and (111) and the properties of the artificial leather 1 Comp Vl-l Exp Vl-l Exp V1-2 Exp V1-3 Exp Vl-4 Exp Vl-5 Exp Vl-6 Comp Vl-2 mean particle diameter of CaCO; (micron) 0.01 0.03 0.10 0.50 2.00 3.00 5.00 8.00 thick. of C.L. (I) (mm) 0.009 0.009 0.009 0.009 0.009 0.009 0.009 0.009 thick. of C.L. (11) (mm) 0.18 0.19 0.20 0.20 0.20 0.22 0.22 0.24 thick. of C.L. (111) (mm) 0.63 0.65 0.68 0.70 0.70 0.71 0.72 0.72 thick. of A.L. (mm) 1.519 1.549 1.589 1.609 1.609 1.639 1.649 1.669 St. of Disp. of caco, A O 0 O A X A. Density Diff. between 0.16 0.15 0.17 0.15 01.8 0.13 0.13 0.12 C.L.(111) and (11) (g/cm) 20% modulus of C.L.(1)(kglcm) 25.5 25.5 25.5 25.5 25.5 25.5 25.5 25.5 App. of crease x O O A X C.F.A. (degree) 20 60 80 105 100 80 60 30 ER. (X 10 times) 10.4 38.5 45.5 46.0 42.5 40.1 35.5 2.5 W.V.P. (mg/cm hr.) 5.5 10.5 13.0 15.5 16.0 16.0 16.0 12.0 softness x O 0 O O X Sur. Sm. x O O 0 A x Table 7 (Exp. V11) Kind of inorganic compound in C.C. (11) and (111) and the properties for artificial leather ExpVll-l ExpVl1-2 ExpVl1-3 ExpV11-4 Kind of inorganic compound (inorg. comp.) ZnO TiO, ZnCO Kaolinite mean particle diameter 1.5 0.9 1.3 0.9

(micron) St. of Disp. of inorg. comp. thick. of C.L. (1) (mm) 0.01 0.01 0.01 0.01 thick. of C.L. (11) (mm) 0.20 0.18 0.20 0.19 thick. of C.L. (111) (mm) 0.68 0.68 0.66 0.67 thick. of A.L. (mm) 1.59 1.57 1.57 1.57 A. density Diff. (glcm) 0.17 0.18 0.15 0.15

(C.L.(llMlll) modulus of C.L.(l) 2 23.5 23.5 23.5 23.5

(kg/cm App. of crease 7 C.F.A. (degree) 105 105 95 105 F.R. (X 10 times) 40.5 38.5 41 8 42.0 W.V.P (mg/cm hr.) 15.5 14.5 15 0 15.0 softness Sr. Sm. Eas. in Shoemak. Fit. to foot EXPERIMENT V111 Eight kinds of PU shown in Table 8 were used in coating composition (1). of PU solution was prepared by picking up the proper ratios of NCO/OH on the addition reaction and by changing the mean molecular weight of polymer diol. The values of various 20% moduli of PU thus obtained are shown in Table 8. Thus 20% modulus of coating layer (1) was changed as shown in Table 8. Eight kinds of artificial leather were prepared according to Experiment 1 and Experiment l-l except for using polyurethane mentioned above for coating composition (1).

20% modulus of coating layer (1) was effective to appearance of creases, crease-forming angle, and flexibility resistance of artificial leather as shown in Table 9. To obtain good results above mentioned, from 5 to 100 kg/cm of 20% modulus of coating layer (1) was satisfactory, more satisfactory from 10 to 70 kg/cm and the most satisfactory from 15 to kglcm EXPERlMENT lX With the same conditions as in Experiment 1 and Experiment l-l except that coating layer (11), and (111) whose apparent densities were different from each .other were prepared, 8 kinds of artificial leather were Table 8 (Exp. V111) Various kinds of PU and their 20% Modulus (NCO/ Viscosity Kinds of PU (OH) 25% PU/DMF 20% Modulus mole ratio soln (poise) (kg/cm") PEG-DPMDl-TMD 2 700 3 PEG-DPMDI-MBA 2 750 5 PTHF-DPMDl-TMD 2 660 10 PCL/PEA-DPMDl- 2 720 15 MBA PEA-DPMDl-MBA 3 650 50 PBA DPMD1-MBA' 4 680 PCL/PEA-DPMD1- 5 705 MBA Table 8 (Exp. VlIl)Continued Various kinds of PU and their 20% Modulus Table 1 l-l shows that it is necessary to make the thickness of coating layer (1) from 0.001 to 0.1 mm. On the conditions of Table 11-2, 8 kinds of artificial leather (from Experiment X-7 to X-l2 and Comparison X-3 to X-4 as shown in Table 11-2) were prepared according to Experiment I and Experiment I-l except that the thickness of coating layer (11) was changed and that the value of the thickness of coating layer (I) and (III) was kept as shown in Table 1 1-2 which is a favorable value according to this invention. Table 1 1-2 shows that it is necessary to make the thickness of coating layer (11) from about 0.01 to about 0.30 mm.

Using the conditions of Table 1 1-3, 8 kinds of artificial leather (from Experiment X-13 to X-18 and Comparison X-5 to X-6 as shown in Table 11-3) were prepared according to Experiment I and Experiment l-l Table 9 (Exp. VIII) 20% modulus of C. L. (I) and the properties of artificial leather Comp Exp Exp Exp Exp Exp Exp Comp VIII-1 Vlll-l VIII-2 VIII-3 VIII-4 V11l5 VIII-6 Vlll-Z 20% modulus of C.L. I

(kg/cm) 3 5 1O 15 100 200 thick. of C.L. (1) (mm) 0.008 0.008 0.008 0.008 0.008 0.008 0.008 0.008 thick. of C.L. (11) (mm) 0.20 0.19 0.20 0.21 0.20 0.18 0.20 0.19 thick. of C.L. (111) (mm) 0.71 0.70 0.70 0.69 0.69 0.70 0.70 0.71 thick. of leather (mm) 1.618 1.598 1.608 1.608 1.598 1.588 1.608 1.508 A. density Diff. between I l 16 015 015 017 017 013 015 O 14 C.L. (111) and (11) (g cm 0. App. of crease X 0 O O O X C.F.A. (degree) 15 6O 110 110 70 45 F.R. (X 10 times) 44.5 44.2 43.6 45.0 48.5 42.7 40.1 9.5 W.V.P. (mg/cm hr.) 15.0 15.0 15.3 16.5 15.5 15.0 15.5 15.2 softness O O X Table 10 (Exp. IX)

Apparent density difference of C. L. (111) and (I1) and properties of artificial leather Comp Exp Exp Exp Exp Exp Exp Comp lX-l lX-l 1X-2 lX-3 1X-4 1X-5 1X-6 1X-2 A. Density Diff. between C.L. (Ill) and (II) (g/Cm) 0.00 0.05 0.07 0.08 0.40 0.60 0.80 1.00 thick. of C.L. (1) (mm) 0.009 0.009 0.009 0.009 0.009 0.009 0.009 0.009 thick. of C.L. (ll) (mm) 0.20 0.19 0.20 0.18 0.20 0.19 0.20 0.22 thick. of C. L. (III) (mm) 0.69 0.70 0.70 0.70 0.55 0.53 0.21 0.10 thick. of A.L. (mm) 1.599 1.599 1.609 1.589 1.559 1.429 1.119 1.029 20% modulus of C. L. (l)

' (kg/cm) 23.8 23.8 23.8 23.8 23.8 23.8 23.8 23.8 App. of crease x A O A x C.F.A. (degree) 15 60 95 65 25 F.R. (X 10 times) 2.0 18.5 30.7 46.5 48.0 35.0 20.0 5.0 W.V.P. (mg/cm hr.) 15.0 15.2 15.5 15.0 15.0 10.0 8.4 2.1 softness x A 0 O A x repulsive elasticity x A 0 Q A x Eas. in shoemak. x O O 0 O x Fit. to foot x A O 0 A x Repulsive elasticity x strongest A stronger O strong weak EXPERIMENT X except that the thickness of coating layer (111) was changed and that the value of the thickness of coating layer (1) and (II) was kept as shown in Table 11-3, which is favorable value according to this invention. Table 1 1-3 shows that it is necessary to make the thickness of the coating layer (111) from about 0.10 to about 3.00 mm. It was found that the favorable thickness of fibrous substrate was from about 0.3 to 3.0 mm and that a more favorable thickness was from about 0.5 to 1.5 mm for shoes, bags, sheets, interior materials, etc., for ease of processing, although the optimum thickness of the thickness above mentioned gave good results.

An artificial leather consisting of coating layer (1). (III) and fibrous substrate without coating layer (II) was prepared, but flexibility resistance of this artificial leather was very poor (0.2 X times), and shoes made of this artificial leather were so poor that cracks 10 occurred in about one day when the shoes were worn. Also, their scuff resistance was very weak (200 g), and the shoes were easily scratched when worn.

EXPERIMENT XI Artificial leather was prepared according to Experiment I and Experiment I-1 except that the kinds and the amounts of polymer excluding PU used in coating composition (I), (II) and (III) were changed. Polyvinyl 2O chloride, copolymer of vinyl chloride and vinyl acetate,

and polybutyl acrylate were used as the polymer above mentioned. The amount of each polymer was 0, and wt% in the case of coating composition (1) and (II), and O, 40 and wt% in the case of coating composition (111). In the case of coating composition (1) and (II) it was found from this experiment that no difference among these kinds of polymer was observed, and that it was necessary to keep the amount of polymer except for PU..less than about 20 wt% to obtain good artificial leather according to this invention. And in the case of coating composition (III), it was found that no difference among these kinds of polymer was also observed, and that it was necessary to keep the amount of polymer, except for PU, less than about 40 wt% to obtain good artificial leather of this invention.

Addition of these polymers excluding PU improved scuff resistance (by 100 to 200 g in comparison with zero addition), ease in shoemaking and repulsive elasticity. An artificial leather with poor properties was obtained by using polystyrene as the polymer above mentioned.

Thickness of C. L. (I) and properties of artificial leather Table 11-1 (Exp. X)

Comp xp Exp Exp Exp Exp Exp Comp X-l X-I X-2 X-3 X-4 X-5 X-6 X-2 thick. ofC.L. (1) (mm) 0.0005 0.001 0.003 0.005 0.02 0.05 0.10 0.50 thick. of C.L. (II) (mm) 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 thick. 0fC.L. (111) (mm) 0.69 0.69 0.69 0.69 0.69 0.69 0.69 0.69 thick. of A.L. (mm) 1.5705 1.561 1.573 1.565 1.58 1.62 1.65 2.05 20% modulus of C.L. (I) (kg/cm) 25.5 25.5 25.5 25.5 25.5 25.5 25.5 25.5 A. Density Diff. between C.L. (111) and (11) (g/cm 0.15 0.16 0.16 0.15' 0.15 0.17 0.15 0.16 App. of crease x A O Q A x C.F.A. (degree) 5 42 60 120 105 8 Sur. Sm. x A 0 0 A x Color'and luster of surface x A O F.R. (X 10 times) 2.0 11.5 36.3 42.5 53.0 50.7 38.4 20.1 W.V.P. (mg/cm hr.) 16.3 16.3 15.7 15.5 14.1 10.3 7.0 0.1 softness 0 A x 1-1.R. C) 1 10 150 200 280 280 280 280 280 SR. (g) 500 800 900 1200 1500 1500 1500 1500 Color and luster of surface better good A bad x worse Table 11-2 (Exp. X)

Thickness of C. L. (11) and properties of artificial leather Comp Exp Exp Exp Exp Exp Exp Comp X-3 X-7 X-8 X-9 X-10 X-l 1 X-12 X-4 thick. of C. L. (1) (mm) 0.009 0.009 0.009 0.009 0.009 0.009 0.009 0.009 thick. of C. L. (11) (mm) 0.005 0.01 0.03 0.05 0.20 0.25 0.30 1.0 thick. of C. L. (111) (mm) 0.69 0.69 0.69 0.69 0.69 0.69 0.69 0.69 thick. of A. L (mm) 1.404 1.419 1.429 1.449 1.589 1.649 1.679 1.699 20% modulus of C. L. (I)

(kg/cm) 25.5 25.5 25.5 25.5 25.5 25.5 25.5 25.5 A. Density Diff. between C.L. (I11) and (11) (g/cm) 0.16 0.15 0.15 0.17 0.16 0.16 0.17 0.15 App. of crease 0 A x C.F.A. (degree) 85 90 80 60 15 F.R. (X 10 times) 1.8 12.5 28.7 39.8 45.5 48.2 48.6 49.5 W.V.P. (mg/cm hr.) 10.2 10.6 14.3 16.0 15.8 15.1 10.3 8.0 S.R. (g) 400 800 1000 1400 1400 1400 1400 1400 softness O A x Repulsive elasticity 8 O 2 x Eas. in'Shoemak. x O x Fit. to foot O O Q g O A x Table ll-3 (Exp. X)

Thickness of C. L. (111) and properties of artificial leather Comp Exp Exp Exp Exp Exp Exp Com X-S X-13 X-14 X-15 X-16 X-17 X-18 X-6 thick. of C. L. (1) (mm) 0.009 0.009 0.009 0.009 0.009 0.009 0.009 0.009 thick. OTC. L. (11) (mm) 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 thick of C. L. (111) (mm) 0.05 0.10 0.30 0.50 1.00 2.00 3.00 5.00 thick. of A. L. (mm) 0.939 0.989 1.179 1.389 1.879 2.879 3.889 5.869 20% modulus of C. L (I) (kg/cm) 25.5 25.5 25.5 25.5 25.5 25.5 25.5 25.5 A. Density Diff. between C.L. (I11) and (II) (g/cm) 0.15 0.15 0.15 0.16 0.16 0.15 0.14 0.15 App. of crease x A O A x C.F.A. (degree) 13 43 65 98 107 110 105 75 F.R. (X times) 3.5 11.0 29.5 36.8 41.4 28.8 28.1 8.6 W.V.P. (mg/cm hr.) 15.4 15.7 15.0 14.7 13.5 10.2 3.4 5.4 $.R. (g) 1200 1200 1300 1400 1400 800 700 200 softness O A A repulsive elasticity O O O A A Eas. in shoemak. x A 0 0 A x Fit. to foot x A O O O O A A EXPERIMENT XII PU used for impregnating composition were changed.

The following PU used in coating composition (1), (II) and (III) was chosen.

1. polyester PU (prepared from the following starting material (a), (b) and (c) (a) polymer diol: PCL, PEA, PBA, polyethylene butylene adipate diol (b) di-isocyanate (c) di-amine and/or lower molecular diol 2. polyether PU (a) polymer diol: PTHF, PPG (polypropylene glycol), polypropylene-tetra-methylene-oxide glycol (b) di-isocyanate (c) di-amine and/or lower molecular diol 3. polyether-ester PU a. polymer diol: ether-ester-diol, obtained from polytetra-methylene oxide glycol, :phthalic acid and ethylene glycol, and other ether-ester-diols b. di-isocyanate c. di-amine and/or lower molecular diol 4. PU combined with (l), (2) and (3) a. polymer diol: mixture of polymer diol of l (2) and (3) b. di-isocyanate c. di-amine and/or lower molecular diol The following PU was chosen as representative and an artificial leather was prepared according to Experiment I and coating composition (III), according to Experiment I-l.

l. PCL-DPMDl-MBA 2. PTHF-DPMDI-MBA 3. PDEGA-DPMDI-MBA (PDEGA ethylene oxide glycol adipate) 4. PTHF PCL-DPMDI-MBA (PTHF/PCL 75/25 (mol/mol)) The artificial leather obtained from the above PU (l), (2), (3) and (4) brought good results according to this invention. Especially in the case of( l an artificial leather with good scuff resistance was obtained, in the case of (2), with good softness and water vapor permeability, in the case of (3), with good flexibility resistance and softness, and in the case of (4). with good scuff resistance, softness and water vapor permeability.

poly di- EXPERIMENT XIII In this experiment the viscosity of the DMF solution with wt% of PU used for coating layer (1). (II) and (Ill), and the viscosity of DMF solution with 25 wt% of Namely, for coating layer (1) and the impregnating composition both of these viscosities were 10, 50, 100, 300, 800, 1500, 3,000 and 5,000 poises at 20C, and for coating layer (11) and (III) they were 100, 200, 500, 800, 2,000, 3,000, 5,000 and 8,000 poises at 20C. By using said DMF solution with 25 wt% of PU, coating compositions (I), (II), (III) and the impregnating composition were prepared. The polymer used for coating compositions (I), (II), (III) and impregnating composition was the same kind as PU as used in Experiment 1. Thus artificial leathers were prepared according to Experiment I and Experiment [-1. As a result it was found that, when the viscosities mentioned below were used, the resulting artificial leather had a satisfactory appearance of creases, a large crease-forming angle, superior flexibility resistance, strong scuff resistance, wonderful softness, great repulsive elasticity, etc., all at the same time.

Namely, the satisfactory extent of the viscosity of the DMF solution with 25 wt% of PU used for the coating layer (1) and the impregnating composition was from about 50 to 3,000 poises at 20 C, more satisfactory from about 100 to l,500 poises and most satisfactory from about 300 to 800 poises. And the satisfactory range of viscosity of the DMF solution with 25 wt% of PU used for the coating layers (11) and (111) was from about 200 to 5,000 poises at 20 C, more satisfactory from about 500 to 3,000 poises, and the most satisfactory from about 800 to 2,000 poises.

1n the preparation of coating layers (11) and (111), it is important to obtain a microporous structure by the wet-coagulating method. And it is also important that the state of dispersion of the inorganic compound in the coating composition should be substantially homogeneous. For the reason mentioned above, it is considered that good results were obtained in the range of viscosities mentioned above.

EXPERIMENT XIV By making a web of polyethylene terephthalate staple fibers of ultra fine fiber bundle in which each fiber had a denier of 0.08, and needle-punching the web, a nonwoven fabric was made. Artificial leather was prepared according to Experiment I. Coating composition (ill) in Experiment I-l was used as coating composition (Ill).

The resulting artificial leather was superior in softness and flexibility resistance X 10 times) and the appearance and feel of this artificial leather were just the same as that of German Box Calf. The appearance of creases and the crease-forming angle were almost the same as Experiment I. The ease in shoemaking was superior. The shoes from this artificial leather gave no discomfor when worn.

EXPERIMENT XV The surface ofwet-treated fibrous substrate was flattened by the dispersion liquid of poly-ethyl acrylate and water (30:70 by weight), and then on this surface, coating layers (II) and (III) were applied and pressed. Thus, artificial leather was prepared according to Experiment I. Coating composition (III) in Experiment I-l was used as coating composition (III). The appearance of creases of this artificial leather was superior, the crease-forming angle was 105 the flexibility resistance was very excellent (65 X times), and the scuff resistance was excellent (2000g). When the above mentioned flattening treatment was not done, the flexibility resistance was 40'to 45 X 10 times, and the scuff resistance was from 1,300 to 1,500 g.

EXPERIMENT XVI Flattening treatment of surface of the fibrous substrate in Experiment XV is explained as follows.

There are many ways of carrying this treatment into effect, and the following examples are representative. (Experiment was carried out according to Experiment I and Experiment I-l I. The surface of wet-treated fibrous substrate in Experiment I was flattened by coating with PU and/or a dispersion liquid composed of alkyl'poly-acylate and water. On this flattened surface, the surface of coatinglayer-(III)-side of multi-layer material of coating layer (II) and (III) was applied, and pressed lightly, then immersed into water to coagulate. Then, on the surface of coatingjayer (II), coating layer (I) was applied. Thus, artificial leather was prepared.

2. In the process wet-treated fibrous substrate and a multi-layer material of coating layers (II) and (III) was joined and pressed, a part of coating layer III) was buried into'the fibrous substrate by regulating the pressure during the pressing operation, and the surface of coating layer (II) was smoothed, and then this material was immersed in water to cause coagulation. Finally, on the surface of coating layer (II), coating layer (I) was applied. Thus, artificial leather was prepared.

3. Drying the wet-treated fibrous substrate, on one side of this fibrous substrate, the layer of the solution of'the polymer=used in ('1) or the dispersion liquid of the polymer used in (l) was applied and dried. The flattening of the surface of the fibroussubstrate was thus accomplished. On this flattened surface of the fibrous substrate, the multi-layer of coating layers (II) and (III) was applied and then, on the surface of coating layer (II), coating layer (I) was applied. Thus, artificial leather was prepared.

The artificial leather obtained by the method of l) and (2) above mentioned had superior flexibility resistance, scuff resistance, and water vapor permeability. The properties of the artificial leather obtained by the method of (3) were as superior as those of l) and (2) except for water vapor permeability.

Example: I

65 X 10 times 16.0 mg/cm hr. 1800 g The flexibility resistance of the artificial leather containing ultra fine fiber bundles and with flattening treatment was very excellent (more than 100 X 10" times).

The following is claimed:

1. Artificial leather comprising a fibrous substrate having a thickness of about 0.3 to 3.0 mm, said fibrous substrate comprising a sheet of ultra fine fiber bundles and polymer impregnated therein, in which the denier 'of each fiber is about 0.01 to 1.0 denier, and coating layers (III), (II) and (I) adhered in that order to the surface of said substrate, with the coating layer (III) immediately on the surface of the substrate,

a. the coating layer (III) having a thickness of about 0.1 to 3.0 mm, and comprising a wet coagulated polymer composition which contains about .50 to 300 parts by weight of inorganic particles per 100 parts by weight of polymer, said inorganic particles having a mean particle diameter of about 0.03 to 5.0 micron and being essentially insoluble in water, and the polymer in this polymer composition consisting of at least about 60 percent by weight of polyurethane,

b. the coating layer (II) having a thickness of about 0.01 to 0.3 mm, and comprising a wet coagulated polymer composition which contains about 0 to 50 parts by weight of inorganic particles per 100 parts by weight of polymer, said inorganic particles having a mean particle diameter of about 0.03 to 5.0 micron and being essentially insoluble in water, and the polymer in this polymer composition consisting of at least about 80 percent by weight of polyurethane, and

. the coating layer (I) having a thickness of about 0.001 to 0.1 mm and having a 20% modulus of about 5 to 100 kg/cm and comprising a drycoagulated polymer composition, consisting essentially of at least about 80 percent by weight of polyurethane.

2. The artificial leather as claimed in claim 1, wherein the thickness of said fibrous substrate is about 0.5 to 1.5 mm and the fibrous substrate comprises polymer and non-woven fabric composed of said ultra fine fiber bundles.

3. Artificial leather as defined in claim 1, wherein the thickness of said fibrous substrate is about 0.5 to 1.5 mm, the thickness of said coating layer (I) is about 0.003 to 0.05 mm, the 20% modulus of said coating layer (1) is about 10 to kglcm the thickness of said coating layer (II) is about 0.03 to 0.25 mm, said coating layer (II) contains about 0 to 20 parts by weight of inorganic compound particles per 100 parts by weight of polymer, these inorganic particles having a mean particle diameter of about 0.1 to 3.0 micron, and being essentially insolublein water, the thickness of said coating layer (III) is about 0.3 to 2.0 mm, said coating layer (III) contains about to 200 parts by weight of inorganic compound particles per parts by weight of polymer, and these inorganic compound particles having a mean particle diameter of about 0.1 to 3.0 micron and being essentially insoluble in water.

4. Artificial leather as claimed in claim 1, wherein the thickness of said coating layer (I) is about 0.005 to 0.02

to 50 kg/cm the thickness of said coating layer (11) is about 0.05 to 2.0 mm, said coating layer (II) is essentially free of inorganic particles, the thickness of said coating layer (111) is about 0.5 to 1.0 mm, said coating layer (111) contains about 120 to 160 parts by weight of inorganic compound particles per 100 parts by weight of polymer, and these inorganic compound particles have a mean particle diameter of about 0.5 to 2.0 micron and are essentially insoluble in water.

5. Artificial leather as claimed in claim 1, wherein said polymer contained in said coating layers (I) and (II) is composed of more than 80 wt% of polyurethane and less than wt% of another polymer selected from the group consisting of polyvinyl chloride, poly- -mm, the 20% modulus of said coating layer (1) isabout layers (-II) and (III) are about 800 to 2.000 poises at 20 10. Artificial leather as claimed in claim 1, wherein the inorganic compound contained in said coating layvinylidene chloride, poly-vinyl acetate, poly-acrylic acid, alkylpolyacrylate, poly-methacrylic acid, alkylpoly-methacrylate, a copolymer consisting of at least one of the above mentioned polymer segments, and mixtures of the above mentioned polymer, and said polymer contained in said coating layer (111) is composed of more than about 60 percent by weight of polyurethane and less than about 40 percent by weight of such other polymer.

6. Artificial leather as claimed in claim 1, wherein the polyurethane contained in said coating layer (I), (II) and (III) is the reaction product of a polymer diol, diisocyanate and di-amine and/or lower molecular diol,

- wherein the polymer diol is at least one kind of polymer diol from the group composed of poly-ether-diol, polyester-diol and poly-ether-estendiol, and the polymer impregnated in said sheet is selected from the group consisting of said polyurethane, polyvinyl chloride, copolymer of vinyl chloride and vinyl acetate, polyacrylic acid and its ester, and poly-meth-acrylic acid and its ester, and a mixture of more than about 50 percent by weight of said. polyurethane and less than about 50 percent by weight of said other polymer.

7. Artificial leather as claimed in claim 1, wherein a dimethyl 'formamide solution with percent by weight polyurethane is used in said coating layer (I) and said impregnating composition, having a viscosity of about 50 to 3,000 poises at 20C, and dimethyl formamide solutions with 25 wt% are used in said coating layers (11) and (III), having a viscosity of about 200 to 5,000 poises at 20 C.

8. Artificial leather as claimed in claim 1, wherein the viscosities of dimethyl formamide solution with 25 wt% of polyurethane used in said coating layer (I) and said impregnating composition are about 100 to 1,500 poises at 20 C, and the viscosities of dimethyl formamide solution with 25 wt% of polyurethane used in said coating layers (11) and (III) are about 500 to 3,000 poises at 20 C.

9. Artificial leather as claimed in claim I, wherein the viscosities of dimethyl formamide solution with 25 wt% of polyurethane used in said coating layer (I) and said impregnation composition are about 300 to 800 poises at 20 C, and the viscosities of dimethyl formamide solution with 25 wt% of polyurethane used in said coating ers (II) and (III) is selected from the group consisting I of calcium carbonate, zinc oxide. titanium oxide, zinc carbonate and kaolinite, and mixtures thereof.

11. Artificial leather as claimed in claim 1, wherein the apparent density difference between coating layers (III) and (II) is about 0.05 to 0.8 g/cm, and the apparent density of said coating layer (III) is larger than that of said coating layer (II).

12. Artificial leather as claimed. in claim I, wherein the apparent density difference between said coating layers (III) and (II) is about 0.07 to 0.6 g/cm". and the apparent density of said coating layer (111) is larger than that of said coating layer (11).

l3. Artificial leather as claimed in claim 1, wherein the apparent density difference between said coating layers (III) and (II) is about 0.08 to 0.4 g/cm, and the apparent density of said coating layer (III) is larger than that of said coating layer (II).

14. Artificial leather as claimed in claim 1, having a crease-forming angle of more than about 40.

15. Artificial leather as claimed in claim 1, having a 3 crease-forming angle of more than about 60.

16. Artificial leather as claimed in claim 1, havinga crease-forming angle of more than about 17. Artificial leather as claimed in claim 1, wherein the water vapor permeability is more than about 3.0 mg/cm hr. and the flexibility resistance is more than about 10 X 10 times.

18. Artificial leather as claimed in claim 1, wherein the water vapor permeability is'more than about 5.0

-mg/cm hr. and the flexibility resistance is more than about 15 X 10 times.

19. Artificial leather as claimed in claim 1, wherein the water vapor permeability is more than about 8.0 mg/cm hr. and the flexibility resistance is more than about 20 X 10 times.

20. Artificial leather as claimed inclaim 1, wherein the entire thickness of the multi-layer composed of said coating layers (11) and (111), not including said fibrous substrate, is about 0.1 to 3.6 mm.

21. Artificial leather as claimed in claim 1, wherein the entire thickness of the multi-layer composed of said coating layers (11) and (111), not including said fibrous substrate, is about 0.3 to 2.0 mm.

22. Artificial leather as claimed in claim 1, wherein the entire thickness of the multi-layer composed of said coating layers (11) and (III), not including said fibrous substrate, is about 0.5 to 1.5 mm.

23. Artificial leather as defined in claim 1, wherein layer (111) is thicker than layer (11).

24. Artificial leather as defined in claim 1, wherein layer (11) is thicker than layer (I).

25. Artificial leather as defined in claim 1, wherein layer (111) is thicker than layer (11) and wherein layer (II) is thicker than layer (1).

Claims

1. ARTIFICIAL LEATHER COMPRISING A FIBROUS SUBSTRATE HAVING A THICKNESS OF ABOUT 0.3 TO 3.0 MM, SAID FIBROUS SUBSTRATE COMPRISING A SHEET OF ULTRA FINE FIBER BUNDLES AND POLYMER IMPREGNATED THEREIN, IN WHICH THE DENIER OF EACH FIBER IS ABOUT 0.01 TO 1.0 DENIER, AND COATING LAYERS (III), (II) AND (I) ADHERED IN THAT ORDER TO SURFACE OF SAID SUBSTRATE, WITH THE COATING LAYER (III) IMMEDIATELY ON THE SURFACE OF THE SUBSTRATE, A. THE COATING LAYER (III) HAVING A THICKNESS OF ABOUT 0.1 TO 3.0 MM, AND COMPRISING A WET COAGULATED POLUMER COMPOSITION WHICH CONTAINS ABOUT 50 TO 300 PARTS BY WEIGHT OF INORGANIC PARTICLES PER 100 PARTS BY WEIGHT OF POLYMER, SAID INORGANIC PARTICLES HAVING A MEAN PARTICLE DIAMETER OF ABOUT 0.03 TO 5.0 MICRON AND BEING ESSENTIALLY INSOLUBLE IN WATER, AND THE POLYMER IN THIS POLUMER COMPOSITION CONSISTING OF AT LEAST ABOUT 60 PERCENT BY WEIGH OF POLYURETHANE, B. THE COATING LAYER (II) HAVING A THICKNESS OF ABOUT 0.01 TO 0.3 MM, AND COMPRISING A WET COAGULATED POLYMER COMPOSITION WICH CONTAINS ABOUT 0 TO 50 PARTS BY WEIGHT OF INORGANIC PARTICLES PER 100 PARTS BY WEIGHT OF POLYMER, SAID INORGANIC PAERTICLES HAVING A MEAN PARTICLE DIAMETER OF ABOUT 0.03 TO 5.0 MICRON AND BEING ESSENTIALLY INSOLUBLE IN WATER, AND THE POLYMER IN THIS POLYMER COMPOSITION CONSISTING OF AT LEAST ABOUT 80 PERCENT BY WEIGHT OF POLYURETHANE, AND C. THE COATING LAYER (I) HAVING A THICKNESS OF ABOUT 0.001 TO 0.1 MM AND HAVING A 20% MODULUS OF ABOUT 5 TO 200 KG/CM2, AND COMPRISING A DRY-COAGULATED POLYMER COMPOSITION, CONSISTING ESSENTIALLY OF AT LEAST ABOUT 80CENT BY WEIGHT OF POLYURETHANE.

3. Artificial leather as defined in claim 1, wherein the thickness of said fibrous substrate is about 0.5 to 1.5 mm, the thickness of said coating layer (I) is about 0.003 To 0.05 mm, the 20% modulus of said coating layer (I) is about 10 to 70 kg/cm2, the thickness of said coating layer (II) is about 0.03 to 0.25 mm, said coating layer (II) contains about 0 to 20 parts by weight of inorganic compound particles per 100 parts by weight of polymer, these inorganic particles having a mean particle diameter of about 0.1 to 3.0 micron, and being essentially insoluble in water, the thickness of said coating layer (III) is about 0.3 to 2.0 mm, said coating layer (III) contains about 80 to 200 parts by weight of inorganic compound particles per 100 parts by weight of polymer, and these inorganic compound particles having a mean particle diameter of about 0.1 to 3.0 micron and being essentially insoluble in water.

4. Artificial leather as claimed in claim 1, wherein the thickness of said coating layer (I) is about 0.005 to 0.02 mm, the 20% modulus of said coating layer (I) is about 15 to 50 kg/cm2, the thickness of said coating layer (II) is about 0.05 to 2.0 mm, said coating layer (II) is essentially free of inorganic particles, the thickness of said coating layer (III) is about 0.5 to 1.0 mm, said coating layer (III) contains about 120 to 160 parts by weight of inorganic compound particles per 100 parts by weight of polymer, and these inorganic compound particles have a mean particle diameter of about 0.5 to 2.0 micron and are essentially insoluble in water.

5. Artificial leather as claimed in claim 1, wherein said polymer contained in said coating layers (I) and (II) is composed of more than 80 wt% of polyurethane and less than 20 wt% of another polymer selected from the group consisting of polyvinyl chloride, poly-vinylidene chloride, poly-vinyl acetate, poly-acrylic acid, alkylpolyacrylate, poly-methacrylic acid, alkyl-poly-methacrylate, a copolymer consisting of at least one of the above mentioned polymer segments, and mixtures of the above mentioned polymer, and said polymer contained in said coating layer (III) is composed of more than about 60 percent by weight of polyurethane and less than about 40 percent by weight of such other polymer.

6. Artificial leather as claimed in claim 1, wherein the polyurethane contained in said coating layer (I), (II) and (III) is the reaction product of a polymer diol, di-isocyanate and di-amine and/or lower molecular diol, wherein the polymer diol is at least one kind of polymer diol from the group composed of poly-ether-diol, poly-ester-diol and poly-ether-ester-diol, and the polymer impregnated in said sheet is selected from the group consisting of said polyurethane, polyvinyl chloride, copolymer of vinyl chloride and vinyl acetate, polyacrylic acid and its ester, and poly-meth-acrylic acid and its ester, and a mixture of more than about 50 percent by weight of said polyurethane and less than about 50 percent by weight of said other polymer.

7. Artificial leather as claimed in claim 1, wherein a dimethyl formamide solution with 25 percent by weight polyurethane is used in said coating layer (I) and said impregnating composition, having a viscosity of about 50 to 3,000 poises at 20*C, and dimethyl formamide solutions with 25 wt% are used in said coating layers (II) and (III), having a viscosity of about 200 to 5,000 poises at 20* C.

8. Artificial leather as claimed in claim 1, wherein the viscosities of dimethyl formamide solution with 25 wt% of polyurethane used in said coating layer (I) and said impregnating composition are about 100 to 1,500 poises at 20* C, and the viscosities of dimethyl formamide solution with 25 wt% of polyurethane used in said coating layers (II) and (III) are about 500 to 3,000 poises at 20* C.

9. Artificial leather as claimed in claim 1, wherein the viscosities of dimethyl formamide solution with 25 wt% of polyurethane used in said coating layer (I) and said impregnation composition are about 300 to 800 poises at 20* C, and the viscosities of dimethyl formamide solution with 25 wt% of polyurethane used in said coating layers (II) and (III) are about 800 to 2,000 poises at 20* C.

10. Artificial leather as claimed in claim 1, wherein the inorganic compound contained in said coating layers (II) and (III) is selected from the group consisting of calcium carbonate, zinc oxide, titanium oxide, zinc carbonate and kaolinite, and mixtures thereof.

11. Artificial leather as claimed in claim 1, wherein the apparent density difference between coating layers (III) and (II) is about 0.05 to 0.8 g/cm3, and the apparent density of said coating layer (III) is larger than that of said coating layer (II).

12. Artificial leather as claimed in claim 1, wherein the apparent density difference between said coating layers (III) and (II) is about 0.07 to 0.6 g/cm3, and the apparent density of said coating layer (III) is larger than that of said coating layer (II).

13. Artificial leather as claimed in claim 1, wherein the apparent density difference between said coating layers (III) and (II) is about 0.08 to 0.4 g/cm3, and the apparent density of said coating layer (III) is larger than that of said coating layer (II).

14. Artificial leather as claimed in claim 1, having a crease-forming angle of more than about 40*.

15. Artificial leather as claimed in claim 1, having a crease-forming angle of more than about 60*.

16. Artificial leather as claimed in claim 1, having a crease-forming angle of more than about 80*.

17. Artificial leather as claimed in claim 1, wherein the water vapor permeability is more than about 3.0 mg/cm2 hr. and the flexibility resistance is more than about 10 X 104 times.

18. Artificial leather as claimed in claim 1, wherein the water vapor permeability is more than about 5.0 mg/cm2 hr. and the flexibility resistance is more than about 15 X 104 times.

19. Artificial leather as claimed in claim 1, wherein the water vapor permeability is more than about 8.0 mg/cm2 hr. and the flexibility resistance is more than about 20 X 104 times.

20. Artificial leather as claimed in claim 1, wherein the entire thickness of the multi-layer composed of said coating layers (II) and (III), not including said fibrous substrate, is about 0.1 to 3.6 mm.

21. Artificial leather as claimed in claim 1, wherein the entire thickness of the multi-layer composed of said coating layers (II) and (III), not including said fibrous substrate, is about 0.3 to 2.0 mm.

22. Artificial leather as claimed in claim 1, wherein the entire thickness of the multi-layer composed of said coating layers (II) and (III), not including said fibrous substrate, is about 0.5 to 1.5 mm.

23. Artificial leather as defined in claim 1, wherein layer (III) is thicker than layer (II).

24. Artificial leather as defined in claim 1, wherein layer (II) is thicker than layer (I).

25. Artificial leather as defined in claim 1, wherein layer (III) is thicker than layer (II) and wherein layer (II) is thicker than layer (I).