KR19990069779A - Solvent-free polyurethane synthetic leather, its manufacturing method and manufacturing apparatus - Google Patents

Abstract

The present invention relates to a solvent-free polyurethane (PU) synthetic leather that does not use an organic solvent in the manufacturing process, and to a manufacturing method and a manufacturing apparatus thereof, and more specifically, to a polyol mixture which is a solvent-free polyurethane raw material ( After the raw material A) and the diisocyanate prepolymer (raw material B) are prepared, these raw materials are mixed and stirred, and coated before the polyurethane forming reaction starts, thereby making polyurethane (PU) synthetic leather.

The present invention does not cause pollution due to the use of the organic solvent by producing a PU synthetic leather by directly reacting the raw materials without using an organic solvent, there is no fear that the organic solvent harmful to the human body remains in the synthetic leather product.

In addition, according to the present invention, a thermosetting polyurethane resin is formed, which is superior in terms of physical properties and texture and close to natural leather, compared to conventional synthetic leather products using thermoplastic resins. Since this is done integrally, it is possible to simplify the work process, shorten the working time and improve productivity.

Description

Solvent-free polyurethane synthetic leather, its manufacturing method and manufacturing apparatus

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic polyurethane-free (PU) synthetic leather that does not use an organic solvent in the manufacturing process, and to a manufacturing method and a manufacturing apparatus thereof. After each of the raw materials B), these raw materials are mixed and agitated at high speed, and are coated instantaneously before the polyurethane forming reaction is started, thereby producing a polyurethane (PU) synthetic leather.

Polyurethane is a generic term for a polymer compound having a large number of urethane bonds (-NHCOO-) in its chemical structure, and urethane bonds are highly reactive and -NCO groups (isocyanate) and active hydrogen, as shown in Scheme 1 below. It is formed by the addition reaction of the compound with -OH group.

Most polyurethanes are made of three basic starting materials: diisocyanate, polymer polyol, and chain extender. The diisocyanate and polymer polyol react to form soft segments In addition, the diisocyanate and the chain extender react to form a hard segment, so that the soft and hard segments exist in one molecule.

Until now, polyurethane resins for coating fabrics are mostly in solution form and are usually classified into one-component resins (or skins), two-component resins (or adhesives), and crosslinking agents. One-component and two-component resins are linear high molecular weights obtained by the polyaddition reaction of polymer diols and chain extenders with about the same moles of diisocyanates as DMF (N, N-Dimethyl formide) and MEK (Methyl ethyl ketone). ) And "polyurethane-organic solvent solution" mainly composed of organic solvents such as TOL (Toluene). Hereinafter, in the present invention, the solution type polyurethane resin means "polyurethane-organic solvent solution."

When one-component resin (skin) removes the solvent, it forms a film and shows excellent film properties by itself. At this time, the film is formed by evaporating the solvent by heating and drying to form a film. By forming a film by means of " wet resin ". As a solvent for wet resins, DMF, which is highly soluble in polyurethane and well mixed with water, is used.

The two-component resin (adhesive) does not form a film alone even if the solvent is removed. A crosslinking agent must be added to form a crosslingked structure to form a film. Generally, it takes about 24 to 48 hours at 50 to 60 ° C for the two-component resin to fully cure (or crosslink).

The crosslinking agent is the addition of 3 moles of trimethyl propane (TMP), 3 moles of TDI (2,4, -Toluene diisocyanate), IPDI (Isophorone diisocyanate), and HDI (Hexamethylene diisocyanate). Since it has a group, it reacts with a two-component resin whose terminal is -OH to form a network structure.

Conventionally, a method of manufacturing a polyurethane synthetic leather is a process using mostly a solution-type polyurethane resin ("polyurethane-organic solvent solution"), usually a solution-type polyurethane resin on a base material such as woven fabric, knitted fabric, non-woven fabric, or release paper It was applied to produce synthetic leather. Such conventional synthetic leather manufacturing methods are classified into a dry method and a wet method.

As shown in Fig. 1, the one-component polyurethane resin is applied to a release paper, and then dried in a heat chamber to form a film by evaporating the solvent, and the two-component polyurethane resin is coated on the formed film, and then the fabric is knitted with a backing material. It is a method of manufacturing synthetic leather by adhering a nonwoven fabric, drying, and then crosslinking in a warm room for one day.

In addition, in the wet method, as shown in FIG. 2, the one-component polyurethane resin is applied to a backing material such as woven fabrics, knitted fabrics, and nonwoven fabrics, and then passed through the water to extract an organic solvent to solidify the polyurethane resin to form a solid film. This is a method of obtaining a synthetic leather by drying in a heat chamber, in which the fine pores of the fine cells are formed in the portion where the organic solvent escapes.

As described above, in the conventional method for manufacturing PU synthetic leather, organic solvents are essentially used in the process, but the use of such organic solvents causes environmental pollution problems worldwide, and organic solvents are known as carcinogenic substances. There was a problem in that it is harmful to the human body if it remains in the final product synthetic leather.

Therefore, although research is being conducted worldwide on the manufacture of solvent-free PU synthetic leather, it is difficult to manufacture a suitable raw material, difficulty in the manufacturing process due to rapid curing of the raw material, product non-uniformity, deterioration of the product compared with conventional synthetic leather, etc. The situation was not practical because of the problem.

Accordingly, the present invention is to provide a solvent-free PU synthetic leather that does not use an organic solvent in the manufacturing process, a manufacturing method and a manufacturing apparatus thereof. In addition, the present invention is to provide a solvent-free PU synthetic leather and its manufacturing method and apparatus that are excellent in physical properties, texture, texture and closer to natural leather compared to conventional synthetic leather using an organic solvent. To this end, in the present invention, a polymer mixture (raw material A) and a diisocyanate prepolymer (raw material B), which are raw materials without using an organic solvent, are prepared, and then the raw materials are directly reacted under the absence of an organic solvent to form a strong polyurethane bond. After mixing and stirring the raw materials, the coating is instantaneously made in the liquid state before the reaction starts to make synthetic leather.

In addition, the present invention is to provide a method for producing a solvent-free PU synthetic leather with a simplified work process by using a specific device capable of instantaneous high-speed mixing, stirring, and coating of raw materials.

1 is a process chart showing a manufacturing process of PU synthetic leather according to the conventional dry method,

2 is a process chart showing a manufacturing process of the PU synthetic leather according to the conventional wet method,

3 is a process chart showing a coating process according to a manufacturing method of a solvent-free PU synthetic leather according to the present invention,

Figure 4a is an illustration of a coating process using a roll coater,

Figure 4b is an illustration of a coating process using a modified roll coater according to the present invention,

Figure 4c is an illustration of a coating process using a release paper coater according to the present invention,

Figure 4d is an illustration of a coating process using a belt-type release paper coater according to the present invention,

5 is a block diagram of a mixing apparatus according to the present invention,

6 is a front view showing a portion of the mixing chamber of the mixing device according to the present invention;

Figure 7a is a front view showing a discharge port portion of the mixing device according to the present invention,

Figure 7b is a side view showing the discharge port portion of the mixing device according to the present invention.

<Description of the symbols for the main parts of the drawings>

11: coater

12a: 1-component polyurethane resin (skin) 12b: 2-component polyurethane resin (adhesive)

13: raw material mixture liquid according to the present invention (raw material A + raw material B)

14: release paper 15: substrate

16: heat seal 17: polyurethane molding film

18: coagulation tank (DMF aqueous solution) 19: turning roll

20: washing tank (water) 21: mixing device

22: roll coater 23a: deformed roll coater

23b: Release paper coater 23c: Belt type release paper coater

24: mixed impeller 25: discharge port

26: inlet for spreading the mixed material 27: mixing chamber

28: tank A 29: tank B

30: strainer 31: raw material transfer pipe

32: raw material feed pump 33: side block

34: motor 35: power transmission belt

36: pulley 37: power transmission shaft

38: mixed raw material discharged 39: screw for raw material stirring

40: nitrogen gas 41: speed conversion motor

Conventional solution type polyurethane resins are obtained by reacting diisocyanate with a polymer polyol in an organic solvent. In contrast, the solvent-free polyurethane resin according to the present invention, without using an organic solvent to directly react the diisocyanate and polyol to make a urethane bond (Scheme 2); By forming cross linking using H ₂ O, a thermosetting resin having a high heat resistance is formed. H ₂ O generates CO ₂ to act as a blowing agent and at the same time yield -NH _{2 as a} by-product (Scheme 3); The resulting -NH ₂ reacts with the -NCO group to form a thermosetting urea bond (Scheme 4); This urea bond (-NHCONH-) is further subjected to biuret reaction with -NCO to form a crosslink (Scheme 5) (Scheme 6); The -NCO group is an allophanate reaction with the -NHCOO group (urethane group) to form a network structure (Scheme 7). These bonds, which are crosslinks, simultaneously form crosslinks with each other (Scheme 8); In addition, they form intermolecular hydrogen bonds with a strong binding force (Scheme 9).

As a result of the reaction, urethane bonds, urea bonds, crosslinks, and intermolecular hydrogen bonds of -OH and -NCO coexist as a whole, thereby forming a thermosetting polymer material having strong intermolecular bonds.

Accordingly, the solvent-free polyurethane resin according to the present invention exhibits excellent heat resistance, wear resistance, and high elasticity as compared with a solution-type polyurethane resin, which is a thermoplastic resin in which a urethane bond is linearly formed.

In the present invention, first, a polyol mixture (raw material A) and a diisocyanate prepolymer (raw material B), which are solvent-free polyurethane raw materials, are prepared, and then mixed and agitated, and when stirred in a liquid state before a strong polyurethane bond is formed and cured. Solvent-free PU synthetic leather is made by coating onto a release paper or substrate in a short time.

The manufacturing method of the solvent-free PU synthetic leather of this invention is largely three processes, (1) Process of making a polyol mixture (raw material A) and a diisocyanate prepolymer (raw material B); (2) mixing and stirring raw materials A and B in a chemical equivalent molar ratio, and (3) coating. Hereinafter, each process is explained in full detail.

(1) Manufacturing process of polyol mixture (raw material A) and diisocyanate prepolymer (raw material B)

A polyol mixture (raw material A) and a diisocyanate prepolymer (raw material B), which are solvent-free polyurethane raw materials, are prepared, respectively.

1) Preparation of a Polyol Mixture (Raw A)

Raw material A by mixing a catalyst and a small amount of water in a polyol selected from a polyester polyol containing a hydroxyl group having a molecular weight of 100 to 10000, a polyether polyol, a modified polyether polyol, a polythioether polyol and a polyol mixed with two or more thereof Make a phosphorus polyol mixture. In this case, the catalyst is used to react polyol and diisocyanate, and a conventional catalyst such as a tertiary amine catalyst such as TEDA (Triethylene diamine) or a metal catalyst such as Sn may be used.

However, when using such a conventional catalyst, the reaction between the polyol and the diisocyanate prepolymer (raw material B) proceeds rapidly, and the viscosity and form of the mixed solution begin to change after about 5-8 seconds after mixing and stirring, so that the coating is very short. Must be done within Therefore, in the present invention, it is preferable to use a delayed catalyst that can delay the reaction between the polyol and the diisocyanate prepolymer more than such a conventional catalyst.

As such a delayed catalyst, a cyclic amidine-based catalyst may be used, and the delayed catalyst may be a urethane reaction, a foaming reaction, and a cross linking reaction of a raw material. Delay. In the present invention, it is preferable to use the delayed catalyst so that the reaction occurs after about 20-30 seconds after mixing and stirring.

The water (H ₂ O) contained in the polyol mixture reacts with diisocyanate to generate CO ₂ and thus acts as a blowing agent, and at the same time yields -NH _{2 as a} by-product (Scheme 3).

In addition, the polyol mixture may further be mixed with a suitable blowing agent in order to adjust the thickness at the time of coating. In addition, a foam stabilizer may be added to adjust the size and structure of the cell to be formed. As the foam stabilizer, a silicone-based surfactant may be used. In addition, a chain extender may be added to control softness, curing time, and the like, and various PU synthetic leathers may be selectively added according to desired functions and preferences. Can be prepared.

2) Preparation of Diisocyanate Prepolymer (Raw B)

Partial reaction of the polyol with organic polyisocyanate yields a diisocyanate prepolymer having a free NCO content of 10-20% at the end (Scheme 10). In this case, a polyester polyol containing a hydroxyl group having a molecular weight of 100 to 10000, a polyether polyol, a modified polyether polyol, a polythioether polyol, or a polyol mixed with two or more thereof may be used. As the organic polyisocyanate, an aliphatic, aromatic, cyclic aliphatic, araliphatic polyisocyanate, etc. may be used. Among these, highly reactive alkene diisocyanate, aromatic diisocyanate, cyclic aliphatic diisocyanate, and araliphatic It is more preferable to use diisocyanate.

(2) Process of mixing and stirring raw materials A and B at precise chemical equivalent molar ratio

The raw material A (polyol mixture) and raw material B (diisocyanate prepolymer) which were manufactured by the process (1) are mixed and stirred by accurate chemical equivalent molar ratio.

Mixing and stirring of the raw materials A and B can be performed by hand, but for more accurate mixing and stirring, it is preferable to use a predetermined mixing device 21 according to the present invention. If raw materials are not mixed in the correct chemical equivalence molar ratio, unreacted raw materials will be left and the quality of the product will be degraded. Therefore, the raw materials should be mixed as accurately as possible.

A preferred embodiment of the mixing apparatus 21 used in the present invention will be described with reference to FIG. The mixing apparatus 21 used in the present invention includes two or more tanks 28 and 29 capable of dividing and feeding the raw materials, and a raw material conveying pipe for transferring the raw materials from the tanks 28 and 29 to the mixing chamber 27 ( 31), the mixing chamber 27 for stirring the transferred raw material and the discharge port 25 for discharging the stirred raw material from the mixing chamber 27, the raw material conveying pipe 31 is the tank (28,29) A raw material conveying pump 32 and a speed converting motor 41 having a speed adjusting function for precisely conveying each raw material in a desired amount from the raw material; The mixing chamber 27 is provided with a mixing impeller 24 for mixing and stirring raw materials at high speed; The discharge port 25 is characterized in that for discharging the stirred raw material from the mixing chamber (27). In addition, the mixing device 21 may maintain a constant temperature and pressure so that the reaction occurs uniformly.

In the present invention, the raw material A liquid and the liquid B are added to the tank A 28 and the tank B 29 provided in the mixing device 21, respectively, and then transferred to the mixing chamber 27 at an accurate chemical equivalent molar ratio. Mix and stir at high speed (preferably 5000-10000 RPM). As for the said mixing and stirring process, it is more preferable to carry out by the constant temperature of 20-60 degreeC, and the constant pressure of 1 kgf / cm <2>.

The raw materials A and B maintain a liquid phase at room temperature, and when the two raw materials are mixed, they react to form a solid. Therefore, after mixing and stirring, the coating should be carried out in the liquid state before the reaction between the two raw materials. Therefore, mixing, stirring, and discharging should be carried out quickly and integrally, and the discharged mixed liquid should be put on the substrate or release paper and coated quickly.

(3) coating process

The mixed and stirred raw material mixture liquid 13 discharged at the process (2) is put on a release paper or a base material, and it is coated using the coater 11 (FIG. 3).

As described above, since the reaction proceeds rapidly after mixing and stirring the raw materials to form a solid polyurethane bond, the coating should be carried out within a short time in the liquid state before the reaction starts. If the coating is not completed within a predetermined time, the curing of the mixed raw material proceeds to form a semi-solid agglomerate, resulting in uneven coating surface and uneven coating thickness.

Therefore, the coating process of the present invention should be selected a method that can perform a coating more quickly, if the coating method that can be completed before the raw material is cured by the addition of the raw material and the coating is integrated into the coating method of the present invention. Suitable. In addition, the conventional coating method such as gravure print mainly used for the application of the solution-type polyurethane resin is not suitable for the coating method of the present invention because the time required for coating is long.

One example of a coating method suitable for the present invention is a method of coating using a roll coater 22 which rotates at a low speed after inserting the raw material mixture 13 onto a substrate (or a release paper) as shown in FIG. 4A. Coating method using the roll coater 22 ". The roll coater 22 is designed in the present invention to solve the problem of a general coater, that is, the coating material remains on the coater and it is hardened to make the coating surface uneven and the coating thickness not constant. (22) "Coating method using" is to rotate the lower part of the roll coater 22, which is coated with the cured coating material, and raise it upward so that the new part contacts the coating material so that the cured raw material does not pass through the coater. It is characterized in that the coating.

Further, as a coating method suitable for the present invention, "coating method using the modified roll coater 23a" (FIG. 4B), "coating method using the release paper coater 23b" (FIG. 4C), " Coating method using a belt release paper coater 23c "(FIG. 4D), etc. are mentioned.

In the coating process of the present invention, the amount of coating material introduced and the speed of the release paper become important factors, and the preferred temperature of the raw material and the release paper in the present coating process is 20 to 60 ° C. After the coating is heated in a heat chamber for about 1 minute and 30 seconds, the reaction temperature rises to about 120 ° C. and when matured at 100 to 150 ° C. for 2 to 5 minutes, a fully cured PU synthetic leather product is obtained.

PU synthetic leather having a variety of appearance can be produced by a conventional post-processing treatment for the solvent-free PU synthetic leather prepared by the above method. That is, after finishing the non-solvent PU synthetic leather obtained in the step (3) by pressing with an embossing roller or by adding a pattern or color by surface treatment to reinforce the physical properties or appearance of the surface or by buffing the surface with sand paper to make suede. By treatment, PU synthetic leather having various appearances can be manufactured using the conventional post-processing equipment as it is.

Hereinafter, the present invention will be described in more detail with reference to examples which do not limit the present invention.

Example 1

Preparation of Raw Material A

(1) Preparation Example 1

64.3 parts by weight of polyester polyol, 0.1 part by weight of a silicone surfactant, 0.01 part by weight of H ₂ O and 0.4 part by weight of a delayed catalyst (cyclic amidine-based) were mixed and stirred to prepare a polyol mixture.

(2) Preparation Example 2

49.2 parts by weight of polyether polyol, 0.6 parts by weight of a silicon foam stabilizer, 0.7 parts by weight of H ₂ O and 0.3 parts by weight of a delayed catalyst (cyclic amidine-based) were mixed and stirred to prepare a polyol mixture.

(3) Preparation Example 3

55.2 parts by weight of polyester polyol, 1.2 parts by weight of a silicon foam stabilizer, 0.9 parts by weight of H ₂ O and 0.2 parts by weight of a delayed catalyst (cyclic amidine-based) were mixed and stirred to form a polyol mixture.

Example 2

Preparation of Raw Material B

(1) Preparation Example 1

A partial reaction of the polyester polyol containing a hydroxyl group having a molecular weight of 100 to 10000 with an aromatic diisocyanate produced a diisocyanate prepolymer having a free NCO content of 18% at the end (Scheme 10).

(2) Preparation Example 2

The polyether polyol containing a hydroxyl group having a molecular weight of 100 to 10000 was partially reacted with an alkene diisocyanate to prepare a diisocyanate prepolymer having a free NCO content of 17% at the end.

(3) Preparation Example 3

A polyester polyol containing a hydroxyl group having a molecular weight of 100 to 10000 was partially reacted with a cyclic aliphatic diisocyanate to prepare a diisocyanate prepolymer having a free NCO content of 19% at the end.

Example 3

Mixing and stirring raw materials A and B

(1) Mixing example 1

Raw material A made in Preparation Example 1 of Example 1 (Polyol mixture: 64.3 parts by weight of polyester polyol, 0.1 part by weight of silicon foam stabilizer, 0.01 part by weight of H ₂ O and 0.4 part by weight of delayed catalyst (cyclic amidine)) To tank A 28 of mixing device 21; 35.2 parts by weight of raw material B (diisocyanate prepolymer) prepared in Preparation Example 1 of Example 2 was introduced into tank B 29 of the mixing apparatus 21; These raw materials are transferred to the mixing chamber 27 at the correct chemical equivalent molar ratio; A mixed solution of a solvent-free raw material was prepared by mixing and stirring at high speed using a mixed impeller. At this time, mixing and stirring were performed under a constant temperature of 40 ° C. and a constant pressure of 1 kgf / cm 2.

(2) Mixing Example 2

Raw material A (polyol mixture: 49.2 parts by weight of polyether polyol, 0.6 parts by weight of silicone foam stabilizer, 0.7 parts by weight of H ₂ O) and a retardant prepared in Preparation Example 2 of Example 1 in tank A 28 of mixing device 21 0.3 part by weight of a type catalyst (cyclic amidine)); Solvent-free raw materials in the same manner as in Mixing Example 1, except that 49.5 parts by weight of raw material B (diisocyanate prepolymer) prepared in Production Example 2 of Example 2 was added to tank B 29 of the mixing apparatus 21. Mixed solution was prepared.

(3) Mixing Example 3

Raw material A (polyol mixture: 55.2 parts by weight of polyester polyol, 1.2 parts by weight of silicon foam stabilizer, 0.9 parts by weight of H ₂ O, and delay) prepared in Preparation Example 3 of Example 1 in tank A 28 of mixing device 21 0.2 part by weight of a type catalyst (cyclic amidine-based catalyst); Solvent-free raw materials in the same manner as in Mixing Example 1, except that 42.5 parts by weight of raw material B (diisocyanate prepolymer) prepared in Preparation Example 3 of Example 2 was added to tank B 29 of the mixing apparatus 21. Mixed solution was prepared.

Example 4

Coating of Raw Material Mixture

(1) "Coating Method Using Modified Roll Coater 23a" (FIG. 4B),

As shown in FIG. 4B, the raw material mixture solution 13 was introduced onto the release paper 14 (or the substrate), and then coated using the modified roll coater 23a according to the present invention. The deformed roll coater 23a is provided with a plurality of coating blades in one coater in a rotatable manner. After coating with the lower coating blade, the coated coating blade is rotated upward and the new coating coating is rotated. By contacting the blade with the coating material is characterized in that the cured raw material does not pass through the coater.

(2) "Coating Method Using Release Paper Coater 23b" (FIG. 4C),

As shown in FIG. 4C, the raw material mixture solution 13 was introduced onto the release paper 14 (or the substrate) and then coated using the release paper coater 23b. Release paper coater (23b) is devised in the present invention, it is characterized in that by using the turning roll 19 to continuously supply a new release paper, the release paper on which the raw material mixture solution is deposited.

(3) "Coating Method Using Belt-Type Release Paper Coater 23c" (Fig. 4D)

As shown in FIG. 4D, the raw material mixture solution 13 was introduced onto the release paper 14 and then coated using a belt-type release paper coater 23c. The belt release paper coater 23c is an improvement on the release paper coater 23b, and the release paper is rotated in a belt form so that it is not necessary to separately supply and recover the release paper. In this case, the release paper with the raw material mixture is rotated and the raw material is rotated. By hardening the mixed solution, removing it and using it again, the same effect as supplying a new release paper is provided.

According to the present invention, there is no environmental pollution due to the use of the organic solvent by producing a PU synthetic leather by directly reacting the raw materials in a short time without using an organic solvent, and there is a fear that organic solvents harmful to human body remain in the synthetic leather product There will be no.

In addition, according to the present invention, since the mixing, stirring and coating of the raw materials are made in a short time, the work process can be simplified, the working time can be shortened, and the productivity can be improved, and various products can be produced using the conventional post-processing equipment as it is. Can be.

In addition, according to the present invention, since the thermosetting polyurethane resin is formed, it is possible to obtain a product closer to natural leather and more excellent in physical properties and texture than conventional synthetic leather products using a thermoplastic resin.

Claims (10)

Solvent-free PU prepared by preparing a polyol mixture and a diisocyanate prepolymer, a solvent-free polyurethane raw material, and then mixing and stirring them in a chemical equivalent molar ratio, and coating on a release paper or a substrate in a liquid state after stirring, before forming a strong polyurethane bond. As synthetic leather; The polyol mixture comprises at least one polyol, a catalyst that activates the reaction between the polyol and the diisocyanate and a small amount of water; The diisocyanate prepolymer is prepared by partially reacting a polyol and an organic polyisocyanate, and is a solvent-free polyurethane synthetic leather, characterized in that the free NCO content of the terminal is 10 to 20%. The solvent-free polyurethane synthetic leather according to claim 1, wherein the mixing is in a ratio of 40 to 65 parts by weight of the polyol mixture and 35 to 60 parts by weight of the diisocyanate prepolymer. (1) Process of preparing polyol mixture and diisocyanate prepolymer which are solvent-free polyurethane raw materials; (2) mixing and stirring the polyol mixture prepared in the step (1) and the diisocyanate prepolymer in an accurate chemical equivalent molar ratio; And (3) A method for producing a solvent-free polyurethane synthetic leather comprising a step of coating a raw material mixed solution 13 mixed and stirred in the step (2) on a release paper or a substrate; The polyol mixture is prepared by mixing at least one polyol with a catalyst and a small amount of water to activate the reaction between the polyol and the diisocyanate; The diisocyanate prepolymer is prepared by partially reacting a polyol and an organic polyisocyanate, and has a free NCO content of 10-20% at the end of the solvent-free polyurethane synthetic leather. Manufacturing method. The polyol of claim 3, wherein the polyol is selected from the group consisting of polyester polyols containing hydroxyl groups having a molecular weight of 100 to 10000, polyether polyols, modified polyether polyols, polythioether polyols, and polyols mixed with two or more thereof. A method for producing a solvent-free polyurethane synthetic leather, characterized in that any one polyol. The method for producing a solvent-free polyurethane synthetic leather according to claim 3, wherein the catalyst is a delayed catalyst capable of further delaying the reaction between the polyol and the diisocyanate prepolymer. The method for producing a solvent-free polyurethane synthetic leather according to claim 3, wherein the coating is performed using a roll coater (22). The method for producing a solvent-free polyurethane synthetic leather according to claim 3, wherein the coating is performed using a modified roll coater (23a). The method for producing a solvent-free polyurethane synthetic leather according to claim 3, wherein the coating is performed using a release paper coater (23b). The method for producing a solvent-free polyurethane synthetic leather according to claim 3, wherein the coating is performed using a belt type release paper coater (23c). A device for mixing, stirring and coating a polyol mixture, which is a solvent-free polyurethane raw material, and a diisocyanate prepolymer integrally, The apparatus includes two or more tanks 28 and 29 capable of dividing and feeding the raw materials, a raw material conveying pipe 31 for transferring the raw materials from the tanks 28 and 29 to the mixing chamber 27, and mixing the transferred raw materials. A stirring chamber 27, a discharge port 25 for discharging the stirred raw material from the mixing chamber 27, and a roll coater 22 for coating the raw material introduced into the substrate or the release paper from the discharge port 25 Lost; The raw material conveying pipe 31 is attached to the raw material transfer pump 32 and the speed conversion motor 41 having a speed adjusting function for transferring each raw material from the tanks 28 and 29 to a desired amount; The mixing chamber (27) is a manufacturing apparatus of solvent-free polyurethane synthetic leather, characterized in that the mixing impeller (24) for mixing and stirring the raw material at high speed.