KR101622621B1 - Synthetic leather for eco-friendly mat and method of manufacturing the same - Google Patents

Abstract

The synthetic leather for an environmentally friendly mat according to the present invention comprises: (i) a fiber substrate layer 10; (ii) an adhesive layer formed on the fiber substrate layer 10 and formed of a two-component polyurethane adhesive having methyl ethyl ketone as a sole solvent (20) and (iii) a surface film layer (30) formed on the adhesive layer (20) and formed by dry coating an anionic polyurethane water dispersion.
In the present invention, an anionic polyurethane aqueous solution is applied and dried on a release paper to form a surface film layer 30, and a two-component polyurethane adhesive solution of methyl ethyl ketone sole solvent is applied and dried on the surface film layer 30 The adhesive layer 20 is formed on the adhesive layer 20 and the fiber substrate layer 10 is laminated on the adhesive layer 20 by a laminating method to dry and aged the adhesive layer 20. The release paper is peeled off from the surface film layer 30, Manufacture synthetic leather for environmentally friendly mat.
The present invention is environmentally friendly, and has excellent surface durability and weatherability since virtually no volatile organic compounds (VOC) harmful to human bodies remain.
Therefore, the present invention is useful as a playroom mat material and the like in which eco-friendliness is particularly required.

Description

Synthetic leather for eco-friendly mat and method for manufacturing the same

The present invention relates to a synthetic leather for environmentally friendly mat which does not substantially contain volatile organic compounds (VOC) harmful to human bodies and a method for producing the synthetic leather. More specifically, the present invention relates to an aqueous leather- (MEK) as a solvent is used as the adhesive layer, the content of volatile organic substances remaining in the product is very small at less than 10 ppm, so that the playroom mat (MAT), and a process for producing the same.

Generally, silver-based synthetic leather is made by wet or dry coating a polyurethane resin on a fiber substrate layer. The polyurethane resin is obtained by polymerizing a polyol, a diisocyanate and a chain extender under a solvent, and dimethylformamide (DMF) and methyl ethyl ketone (MEK) are most widely used because of their good solubility. Such a solvent type polyurethane resin has good film forming processability, excellent physical properties such as abrasion strength, good light fastness and heat resistance, and has been used for a long time in the synthetic leather industry. However, since an organic solvent harmful to human body is used, There is an environmental problem such that the solvent remains in the product.

Synthetic leather is used for various purposes such as clothing, furniture, and shoes. Recently, however, the application range has also been expanded to use as a matting material for a living room or a playroom. The most important consideration when used for this purpose is the human hazards of volatile organic compounds. Dimethylformamide (DMF) stimulates skin, eyes, and mucous membranes, causing liver dysfunction or suspected carcinogens. Toluene causes dermatitis or headache and chronic anemia or gastrointestinal disorders .

In order to solve such a problem, Korean Patent No. 10-1434918 discloses a polyurethane resin comprising methyl ethyl ketone (MEK) as a sole solvent without using dimethylformamide (DMF) And an adhesive layer. However, the polyurethane resin for the surface film layer is polymerized in a high molecular weight under dimethylformamide (DMF) having a strong dissolving power, and there is a problem that the reaction is very difficult in the absence of dimethylformamide (DMF). Korean Patent No. 10-1317873 proposes a method of heating and discharging a pellet of a thermoplastic polyurethane (TPU) elastomer to form a film-like sheet and bonding it with a fiber base layer with ethyl vinyl acetate (EVA) as a solvent have. However, the thermoplastic polyurethane (TPU) has a problem in that it has a low elastic recovery rate and heat resistance, and it is also difficult to mix colors to match colors.

On the other hand, although applications are not limited to use for environmentally friendly mats, attempts have been made to apply aqueous polyurethane to synthetic leather. Korean Patent Registration No. 10-0606950 discloses a polyether polyol having a low content of monools, that is, a high purity of polyether polyol, an excellent bendability and strength, and an improved water resistance and a tacky property of the film . Korean Patent Laid-Open Publication No. 10-2013-0098895 discloses a water-based aqueous composition for a skin layer which is improved in wet heat resistance, hydrolysis resistance and adhesion property at a proper mixing ratio of polyether copolymer polyol, polytetramethylene ether glycol (PTMG) and polycarbonate diol (PCD) A method of synthesizing polyurethane is proposed.

The object of the present invention is to provide a process for producing a synthetic leather for environmentally friendly mats in which the use of an organic solvent is fundamentally excluded or in which a harmful substance hardly remains in the final product by allowing a solvent having a low boiling point to be easily discharged during the process .

Another object of the present invention is to provide a synthetic leather which is particularly environmentally friendly and has excellent surface durability and weatherability due to the absence of any remaining harmful substances and is particularly useful as a playroom mat material.

In order to achieve the above object, in the present invention, an anionic polyurethane water dispersion is applied and dried on a release paper to form a surface film layer 30, and 2 of methyl ethyl ketone sole solvent A liquid type polyurethane adhesive solution is applied and dried to form an adhesive layer 20. The fiber substrate layer 10 is laminated on the adhesive layer 20 by a laminating method and dried and aged. 30) and then heat-treated to produce the synthetic leather for environmentally friendly mat.

At this time, the anionic polyurethane water dispersion liquid is prepared by reacting one kind of polyol selected from a polyether glycol and a mixture of polyether glycol and polycarbonate diol, an alicyclic diisocyanate, an aliphatic diisocyanate and an ionic diol having a carboxyl group to produce an isocyanate terminal Of urethane prepolymer, then neutralizing the subsequently prepared urethane prepolymer with an amine-based neutralizing agent, forcibly dispersing the resulting urethane prepolymer in water, and then continuing the chain extension reaction with diamine.

In the present invention, an aqueous polyurethane containing no organic solvent is applied as a surface film layer, and an adhesive made of methyl ethyl ketone (MEK), which is easily volatilized due to its low boiling point, is easily discharged during the process. Accordingly, the synthetic leather of the present invention is excellent in surface durability and weatherability, and is extremely useful for a playroom mat in which environmental friendliness is particularly required because volatile organic substances including solvents are extremely small. The present invention also has the effect of contributing to the purification of the working process by applying the aqueous polyurethane.

1 is a schematic cross-sectional view of a synthetic leather for environmentally friendly mat according to the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The method for producing a synthetic leather for environmentally friendly mat according to the present invention comprises the steps of (i) mixing one polyol selected from a polyether glycol and a mixture of a polyether glycol and a polycarbonate diol, an ionic compound having an alicyclic diisocyanate, an aliphatic diisocyanate and a carboxyl group The urethane prepolymer at the end of the isocyanate is reacted with the lower diol, and the urethane prepolymer thus produced is neutralized with an amine-based neutralizing agent and then forcedly dispersed in water, followed by chain extension reaction with diamine to obtain an anionic polyurethane water dispersion ; (Ii) coating and drying an anionic polyurethane water dispersion prepared as described above on a release paper to form a surface film layer 30; (Iii) applying and drying a two-component polyurethane adhesive solution of methyl ethyl ketone as a sole solvent on the surface film layer 30 prepared as described above to form an adhesive layer 20; And (iv) laminating, drying and aging the fiber substrate layer 10 on the adhesive layer 20 by a laminating method, peeling the release paper from the surface film layer 30, and then performing heat treatment.

In addition, the method for producing an eco-friendly mat synthetic leather according to the present invention is characterized in that the anionic polyurethane water dispersion is applied to the anionic polyurethane water dispersion before being coated on the release paper, wherein the anionic polyurethane water dispersion is selected from the group consisting of a thickener, Further comprising the step of mixing one or more additives.

Specifically, in the present invention, an isocyanate-terminated urethane prepolymer is obtained by reacting one kind of polyol selected from a polyether glycol and a mixture of polyether glycol and polycarbonate diol, an alicyclic diisocyanate, an aliphatic diisocyanate and an ionic lower diol having a carboxyl group The urethane prepolymer thus prepared is neutralized with an amine-based neutralizing agent and then force-dispersed in water, followed by chain extension reaction with diamine to prepare an anionic polyurethane water dispersion.

The molar ratio of the aliphatic diisocyanate to the aliphatic diisocyanate was adjusted to 40 to 80: 60 to 20, and the reaction was performed at 80 to 100 Deg.] C for 2 to 4 hours, and neutralization is carried out at a temperature of about 80 [deg.] C. Forcible dispersion in water is carried out by adding ion exchange water in a water dispersion tank at about 60 deg. It is preferable to conduct for about 2 hours.

As one embodiment of the present invention for producing an anionic polyurethane water dispersion, 0.9 mole of polytetramethylene ether glycol (PTMG) having a molecular weight (Mn) of 2,000, 0.1 mole of a polycarbonate diol having a molecular weight of 2,000, 1.0 mole of dimethylolbutanooic acid (DMBA), 1.0 mole of isophorone diisocyanate (IPDI) and 1.25 mole of hexamethylene diisocyanate (HDI) were charged into the reaction vessel and reacted at 90 deg. C for 3 hours to prepare an isocyanate terminal urethane prepolymer. A polyurethane water dispersion having a solid content of 35% and a viscosity of 500 cps (25 캜) was prepared using 0.52 mole of triethylamine (TEA) as a neutralizing agent and 0.75 mole of ethylenediamine (ED) as a chain extender.

Polyethylene glycol (PEG), polypropylene glycol (PPG), polytetramethylene glycol (PTMG) and the like having a molecular weight (Mn) of 800 to 3,000 are widely used industrially as the polyether glycol (a ₁ ) In the invention, polytetramethylene glycol (PTMG) is most preferable in terms of hydrolysis resistance and film durability. As the polycarbonate diol (a ₂ ), polypentamethylene carbonate diol (PPCD) having a molecular weight of 1,000 to 3,000, polyhexamethylene carbonate diol (PHCD) and the like are suitable. That is, a polycarbonate diol (PCD) having a straight chain alkylene group having 4 to 10 carbon atoms or a polycarbonate diol (PCD) having a branched alkylene group having 4 to 10 carbon atoms is preferable. Examples of the diisocyanates (b ₁ and b ₂ ) include isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (H ₁₂ MDI), and trans-1,4-cyclohexane diisocyanate Alicyclic diisocyanate is suitable, and as the aliphatic diisocyanate, hexamethylene diisocyanate (HDI) is suitable.

  In the present invention, the molar ratio of NCO (diisocyanate): OH (polyol) is preferably controlled in the range of 1.4 to 1.7: 1. This is to control the molecular weight of the urethane prepolymer at an appropriate level. The ionic lower diol may be a diol having a carboxyl group or a sulfone group, and most preferably dimethylolbutanic acid (DMBA) or dimethylolpropionic acid (DMPA) is commercially available. In the present invention, the molar ratio of the polyol (total of polyether glycol and polycarbonate diol): ionic lower alcohol is preferably 1.8 to 2.5: 1. In this range, the dispersion state of the urethane prepolymer can be optimized. Examples of the neutralizing agent include diethylamine, triethylamine, N-methyldiamine, and the like. As the chain extender, hydrazine, ethylenediamine, 1,4-cyclohexanediamine, adipic hydrazide and the like can be used. Ethylenediamine is most preferable in consideration of polymerization reactivity and film durability.

Next, the anionic polyurethane water dispersion prepared as described above is coated on a release paper and dried to form a surface film layer 30.

More preferably, the anionic polyurethane water dispersion thus prepared is applied to the anion-based polyurethane water dispersion before coating the release paper with at least one additive selected from a thickener, an anti-aggregation agent, a cross-linking agent and an aqueous pigment, And then the prepared compounding liquid may be coated on a release paper and dried to form the surface film layer 30. [

Specifically, as the thickening agent to be added to the anionic polyurethane dispersion, a cellulose-based material such as carboxymethylcellulose, hydroxyethylcellulose, and methylcellulose can be used, and a polyacrylate or a urethane-based thickener can be used. The amount to be used is preferably 0 to 2 parts by mass per 100 parts by mass of the aqueous dispersion depending on the viscosity of the aqueous dispersion.

In order to prevent agglomeration of the aqueous dispersion particles and improve flowability (leveling property), silicone surfactants, particularly polyether modified polydimethylsiloxane, are useful. The amount is preferably 0.5 to 4 parts by mass per 100 parts by mass of the aqueous dispersion.

Addition of a small amount of polyisocyanate, aziridine, carbodiimide, or melamine as a crosslinking agent can improve the water resistance and chemical resistance of the urethane coating. Among them, it is effective to add 0 to 5 parts by mass of aliphatic polyisocyanate or carbodiimide to 100 parts by mass of the aqueous dispersion.

Addition of a small amount of silicone surfactant has an effect of improving the tackiness of the coating, and addition of an antistatic agent can alleviate the generation of static electricity in the coating process. A light stabilizer or an antioxidant may be emulsified in water.

When the compounding liquid is coated on the release paper and dried, preliminary drying is carried out at a temperature of 70 ° C for 2 minutes and secondary drying at about 110 ° C is advantageous for smoothness of the film. When the thickness of the film is 10 to 50 탆, sufficient physical properties are exhibited. When a film thickness of 50 mu m or more is required, coating and drying may be repeated twice.

As an embodiment of producing the surface film layer 30, 10 parts of an aqueous pigment (Toner), 0.5 part of a cellulose-based thickener, and 1.5 parts of a silicone-based coagulation inhibitor were mixed with 100 parts of the anionic polyurethane water dispersion to prepare a blend And then dried at 70 DEG C for 2 minutes and at 110 DEG C for 2 minutes to prepare a film sheet having a film thickness of 40 mu m. The tensile strength of this film was 410 kg / cm 2, elongation 815%, modulus of 100% 30 kg / cm 2, softness and excellent physical properties. The water resistance, heat resistance and light resistance of the film sheet were evaluated as follows.

   1) Water resistance was evaluated as hydrolysis resistance.

    : The film was immersed in a 10% NaOH aqueous solution (25 ° C) for 24 hours.

   2) Evaluation of heat resistance

    : Heat treatment was carried out in a 100 ° C oven for 120 hours.

   3) Light resistance evaluation (UV-test)

    : Irradiated with a 300 W lamp at 50 캜 (black panel temperature) for 120 hours.

After the hydrolysis and heat treatment, the film was in good condition without any yellowing, shrinkage, dissolution and stickiness, and retained its strong physical properties.

As a result of evaluating the light resistance with a UV tester, yellowing was hardly generated with a color difference (DELTA E) of 0.5 or less, and there was no problem in using it as a surface film layer for a matte.

Next, a two-component polyurethane adhesive solution of methyl ethyl ketone as a sole solvent is applied and dried on the surface film layer 30 prepared as described above to form the adhesive layer 20, and then the adhesive layer 20 is formed. The fiber base layer 10 is laminated by a laminating method, dried and aged, and then the release paper is peeled off from the surface film layer 30 and then heat-treated to produce an eco-friendly synthetic leather for a mat.

Two-component polyurethane adhesives usually use dimethylformamide (DMF) and methyl ethyl ketone (MEK) as the main agent. However, in the present invention, a polyurethane adhesive made of methyl ethyl ketone (MEK), which has a relatively low boiling point of 79.6 ° C. and is easily volatilized, is used without dimethylformamide (DMF) solvent which is difficult to volatilize due to its high boiling point. In the present invention, a polyether-based, polycarbonate-based, polyether / polycarbonate copolymer-based polyurethane adhesive is suitable. The solid concentration is preferably 55 to 70%, and when formed into a film, a soft type having a 100% modulus of 15 to 30 kg / cm 2 is preferable.

10 to 20 parts by mass of an isocyanate crosslinking agent and 1 to 5 parts by mass of a crosslinking accelerator are mixed with 100 parts by mass of a polyurethane adhesive, and a small amount of pigment is added to the mixture. Adding 3 to 10 parts by mass of calcium carbonate, talc or the like to the compounding liquid can improve the volume feeling and drape property of the product. If it is added in an amount of 10 parts by mass or more, the adhesive strength may drop sharply. The step of coating the adhesive compounding liquid on the aqueous dispersion film layer and drying and laminating the fiber bubble paper can be continuously performed.

A polyester tricot or circular knitted fabric having a weight of about 200 to 350 g / y (54 inches wide) is suitable for the mat of the present invention.

When the adhesive compound solution is dried for about 2 minutes at about 90 ° C, it is semi-dry, and the evaporation rate of the solvent is about 70 to 90%. The adhesive strength is improved by drying the laminate in this state at about 130 ° C. After that, after aging for 24 hours or more in the aging chamber, the release paper is peeled off. The exfoliated product is further heat-treated at a temperature of 130 ° C or more for 3 minutes or more by using a hot-air drying tenter to completely volatilize the remaining solvent. In addition to the synthetic leather of the present invention thus prepared, an aqueous surface treatment agent can be applied thinly by spraying or gravure roll. This process is useful for improving the touch of the surface or for correcting the color of the final product.

As shown in FIG. 1, the synthetic leather for environmentally friendly mat according to the present invention comprises (i) a fibrous substrate layer 10, (ii) a fibrous substrate layer 10 formed on the fibrous substrate layer 10 and containing methyl ethyl ketone as a sole solvent (Ii) an adhesive layer 20 formed of a two-component polyurethane adhesive; and (iii) a surface film layer 30 formed on the adhesive layer 20 and formed by dry coating an anionic polyurethane water dispersion.

The anionic polyurethane water dispersion is prepared by reacting one kind of polyol selected from a polyether glycol and a mixture of polyether glycol and polycarbonate diol, an alicyclic diisocyanate, an aliphatic diisocyanate and an ionic diol having a carboxyl group to obtain urethane A prepolymer is prepared, and then the urethane prepolymer which is subsequently produced is neutralized with an amine-based neutralizing agent and then forcedly dispersed in water, followed by chain extension reaction with diamine.

The thickness of the surface film layer 30 is 10 to 50 占 퐉 and the thickness of the adhesive layer 20 is 20 to 50 占 퐉 and the weight per unit area of the fiber base layer 10 having a width of 54 inches is 200 to 350 g / (Yard).

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples.

Example  One

≪ Preparation of polyurethane water dispersion >

  0.9 mole of polytetramethylene ether glycol (PTMG) having a molecular weight (Mn) of 2,000, 0.1 mole of polycarbonate diol having a molecular weight (Mn) of 2,000 and 0.5 mole of dimethylol butanone acid (DMBA) 1.0 mole of isophorone diisocyanate (IPDI) and 1.25 mole of hexamethylene diisocyanate (HDI) were charged into the reactor and reacted for 3 hours to prepare an isocyanate-terminated urethane prepolymer. At this time, the content of unreacted NCO group at the terminal was 2.8%. After cooling to 80 ° C, 0.52 mole of triethylamine (TEA) was added, neutralized for 30 minutes, transferred to a 60 ° C water bath, forcedly dispersed by ion exchange water, and 0.75 mole of ethylenediamine (ED) Extension reaction was carried out.

The polyurethane water dispersion thus prepared exhibited no change in apparent viscosity even after storage for more than 2 months with a white emulsion having a solid concentration of 35%, a pH of 7 to 8 and a viscosity of 500 cps.

≪ Preparation of synthetic leather &

0.5 part of a cellulose type thickening agent and 1.5 parts of a white aqueous pigment were added to 100 parts of the aqueous dispersion, and the mixture was thoroughly stirred and then applied on a release paper. The resultant was dried at 70 캜 for 2 minutes and at 110 캜 for 2 minutes to form a film having a thickness of 30 탆 Was formed. Subsequently, 15 parts of an isocyanate crosslinking agent, 3 parts of a crosslinking accelerator, 5 parts of calcium carbonate, 5 parts of a pigment (Toner), 5 parts of a methyl ethyl ketone for dilution (MEK ), Dried at 90 DEG C for 2 minutes, kneaded with a polyester ring circular knitted fabric having a weight of 270 g / y, and further dried at 130 DEG C for 2 minutes.

After aging for 48 hours in the aging chamber at 70 ° C, the release paper was peeled off and heat-treated in a hot-air drying tenter at 130 ° C for 3 minutes to completely discharge the residual solvent. Thereafter, the non-ionic aqueous surface treatment agent was applied by thinly coating with a gravure roll and finished. The final synthetic leather product had a finish of 0.68 mm and a unit weight of 280 g / y (54 inches wide).

Table 1 shows the results of evaluating the physical properties of the manufactured synthetic leather.

Example  2

(PTMG) having a molecular weight of 2,000 and 1.5 mole of isophorone diisocyanate (IPDI) were used as the polyol in the production of the anionic polyurethane water dispersion, A polyurethane water dispersion and a synthetic leather were prepared under the same conditions and in the same manner as in Example 1, except that 0.75 mole of methylene diisocyanate (HDI) was used.

The prepared polyurethane dispersion was a white emulsion having a solid concentration of 35% and a viscosity of 40 cps and showed no apparent viscosity change even after storage for 2 months or more.

Table 1 shows the results of evaluating the physical properties of the manufactured synthetic leather.

Comparative Example  One

Except that the amount of isophorone diisocyanate (IPDI) was changed to 2.25 moles instead of hexamethylene diisocyanate (HDI) in the preparation of an anionic polyurethane water dispersion, the same procedure as in Example 1 was repeated to prepare a polyurethane aqueous dispersion and a synthetic leather .

Table 1 shows the results of evaluating the physical properties of the manufactured synthetic leather.

Comparative Example  2

Except that 2.32 moles of hexamethylene diisocyanate (HDI) was used instead of isophorone diisocyanate (IPDI) in the production of an anionic polyurethane water dispersion, a polyurethane water dispersion and a synthetic leather .

Table 1 shows the results of evaluating the physical properties of the manufactured synthetic leather.

Evaluation items Example 1 Example 2 Comparative Example 1 Comparative Example 2 Assessment Methods Surface Wear Intensity
(Taber, H-22,500 g) 800 times ↑ 700 times ↑ 1,000 times ↑ 300 times ↑ ASTM D4060 Adhesive strength (kg / cm) 1.5 1.8 1.3 1.8 ASTM D2724 I hydrolyse No appearance change No appearance change No appearance change Tacky
Somewhat more 10% NaOH, * 25 < 0 > C * 24HR UV test (DELTA E: 50 DEG C * 300W * 120HR)) 0.1 0.2 0.1 0.2 ASTM G154

The synthetic leather prepared in Examples 1 and 2 was excellent in durability such as surface abrasion strength and adhesive strength for a mat. The synthetic leather produced in Comparative Example 1 was excellent in physical properties, but the surface film layer was rather hard and the overall feel of the product was poor (hard). On the other hand, the product manufactured in Comparative Example 2 had insufficient durability such as abrasion strength, and the stickiness of the film layer was rather strong, so that rolling workability of winding the fabric was not good.

Comparative Example  3

Synthetic leather was produced using ordinary solvent-type polyurethane without using a polyurethane water dispersion.

Specifically, 10 parts by weight of dimethylformamide (DMF), 60 parts by weight of methyl ethyl ketone (MEK), and 10 parts by weight of polytetramethylene ether glycol (PTMG) based polyurethane having a viscosity of 70% And 15 parts by weight of a pigment toner were blended to prepare a coating solution. The coating solution thus prepared was coated on a release paper and dried at 110 DEG C for 2 minutes and at 130 DEG C for 2 minutes. The steps after the adhesive application step were carried out in the same manner as in Example 1.

  The residual amounts of VOC (volatile organic substances) of the synthetic leather produced by Example 1 and Comparative Example 3 of the present invention were evaluated by GC-MS method and are shown in Table 2. In the synthetic leather produced by Example 1, no volatile organic substances were detected within the detection limit.

Measuring substance Example 1 Comparative Example 3 MDL DMF (mg / kg) N.D. 21.9 10 MEK (mg / kg) N.D. 7.84 One Toluene (mg / kg) N.D. N.D. One

* N.D (not-detected): means not detected within the detection limit.

* MDL (Method Detection Limit): detection limit

10: fiber substrate layer 20: adhesive layer
30: surface film layer

Claims (12)

delete delete delete delete delete (I) an isocyanate-terminated urethane prepolymer is prepared by reacting one polyol selected from polyether glycol and a mixture of polyether glycol and polycarbonate diol, an alicyclic diisocyanate, an aliphatic diisocyanate and an ionic lower diol having a carboxyl group Next, the step of neutralizing the subsequently prepared urethane prepolymer with an amine-based neutralizing agent, forcibly dispersing the resulting urethane prepolymer in water, followed by chain extension reaction with diamine to prepare an anionic polyurethane water dispersion;
(Ii) coating and drying an anionic polyurethane water dispersion prepared as described above on a release paper to form a surface film layer 30;
(Iii) applying and drying a two-component polyurethane adhesive solution of methyl ethyl ketone as a sole solvent on the surface film layer 30 prepared as described above to form an adhesive layer 20; And
(Iv) a step of laminating, drying and aging the fiber substrate layer 10 on the adhesive layer 20 by a laminating method, peeling the release paper from the surface film layer 30, and then performing heat treatment By weight of the synthetic leather. 7. The method according to claim 6, wherein the anionic polyurethane water dispersion prepared is mixed with at least one additive selected from the group consisting of a thickener, an anti-aggregation agent, a cross-linking agent and an aqueous pigment, The method of manufacturing a synthetic leather for an environmentally friendly mat according to claim 1, 7. The method of claim 6, wherein the molar ratio of polyether glycol: polycarbonate diol is adjusted to 70 to 100: 0 to 30 during the urethane prepolymer reaction. The method of claim 6, wherein the molar ratio of alicyclic diisocyanate to aliphatic diisocyanate is adjusted to 40 to 80: 60 to 20 during the urethane prepolymer reaction. 7. The method of claim 6, wherein the molar ratio of the polyol: ionic lower diol is controlled to 1.8 to 2.5: 1.0 during the urethane prepolymer reaction. 7. The method of claim 6, wherein the molar ratio of diisocyanate (NCO): polyol (OH) is adjusted to 1.4 to 1.7: 1.0 in the urethane prepolymer reaction. The method of claim 6, wherein the aging is performed at 60 to 80 ° C for at least 24 hours, and the heat treatment is performed at 130 to 140 ° C for at least 3 minutes.

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