Preparation method of waterborne polyurethane environment-friendly mirror leather

Abstract

The invention discloses a preparation method of waterborne polyurethane environment-friendly mirror leather, which comprises the following steps: sequentially coating a release film mirror surface with a waterborne polyurethane surface layer, a waterborne polyurethane middle layer and a solvent-free polyurethane bottom layer; the coated waterborne polyurethane surface layer, waterborne polyurethane middle layer and solvent-free polyurethane bottom layer are a dry-method surface layer, a dry-method middle layer and a dry-method bottom layer in sequence; after the solvent-free polyurethane bottom layer is dried at 130 DEG C for 1.5-2 minutes, base cloth is attached to the bottom layer; after lamination, high-temperature drying and rolling are carried out; after curing at normal temperature for 24 hours, separating the product from the release film by using a stripping paper inspection machine; the surface layer is made of aliphatic polyether anion polyurethane resin and has good transparency and bending resistance and excellent performance, the solvent-free polyurethane mirror surface resin does not foam and is high in transparency and excellent in bending, the glass-transition temperature Tg is smaller than or equal to-15 DEG C, and the mirror surface leather is glossy and transparent.

Description

Technical Field

[0001] The invention relates to the field of mirror leather, and more specifically to a method for preparing waterborne polyurethane environmentally friendly mirror leather. Background Art

[0002] Mirror leather has a smooth and translucent outer surface and beautiful style. It is an important raw material for leather shoes and leather clothes. The existing mirror leather needs to use solvents in the preparation process. The evaporation of solvents pollutes the environment, the working environment is poor, and it is easy to affect the health of workers. Summary of the invention

[0003] In order to overcome the above-mentioned defects of the prior art, the present invention provides a method for preparing a waterborne polyurethane environmentally friendly mirror leather to solve the problems existing in the above-mentioned background technology.

[0004] The present invention provides the following technical solutions:

[0005] A method for preparing waterborne polyurethane environmentally friendly mirror leather comprises the following steps:

[0006] (1) The surface layer has a modulus of 70-100 KPa, a solid content of 20%-40%, and a structure of aliphatic polyether anionic polyurethane resin. The aliphatic polyether anionic polyurethane resin has good transparency and bending resistance, excellent performance, and Tg≤-15°C; 0.5-1.5 of leveling agent, 0.5-1.5 of thickener, and 2-10 of color paste are added according to the weight percentage of the resin. The compatibility of the leveling agent and the resin is high, and the mixture is evenly mixed to obtain a water-based polyurethane surface layer;

[0007] (2) The middle layer has a modulus of 30-50 KPa, a solid content of 20%-40%, and a structure of aliphatic polyester polyether polyurethane resin. The aliphatic polyester polyether polyurethane resin has a low glass transition temperature, Tg of -30°C, and has good adhesion to the solvent-free polyurethane resin. 0.5-1.5 of leveling agent, 0.5-1.5 of thickener, and 2-10 of color paste are added according to the weight percentage of the resin, and the mixture is evenly mixed to obtain a water-based polyurethane middle layer;

[0008] (3) The bottom layer is a solvent-free polyurethane mirror resin with a modulus of 70-100 KPa. The solvent-free polyurethane mirror resin does not foam, has a strong sense of transparency, excellent tortuosity, and a glass transition temperature Tg≤-15°C. The solvent-free polyurethane mirror resin includes a solvent-free polyurethane resin A and a solvent-free polyurethane resin B. According to the ratio of solvent-free polyurethane resin A100 and solvent-free polyurethane resin B100, additives a0.2 and additives b0.05 are added, and the mixture is evenly mixed to obtain a solvent-free polyurethane bottom layer;

[0009] (4) coating a waterborne polyurethane surface layer, a waterborne polyurethane middle layer and a solvent-free polyurethane bottom layer on the mirror surface of the release film in sequence, wherein the waterborne polyurethane surface layer, the waterborne polyurethane middle layer and the solvent-free polyurethane bottom layer after coating are a dry surface layer, a dry middle layer and a dry bottom layer in sequence;

[0010] (5) After baking at 130°C for 1.5-2 minutes, the base fabric is laminated on the bottom layer;

[0011] (6) After lamination, high temperature drying, rolling, or peeling;

[0012] (7) After aging at room temperature for 24 hours, use a peeling paper tester to separate the product and the release film.

[0013] The viscosity of the waterborne polyurethane surface layer in step (1) is adjusted to 500-1500 CPS.

[0014] The leveling agent, thickener and color paste described in step (2) have low VOC, which is required to be less than 50 PPM. VOC is a volatile organic compound. Reducing the amount of VOC is beneficial to home environmental protection and health.

[0015] The viscosity of the waterborne polyurethane intermediate layer in step (2) is adjusted to 500-1500 CPS.

[0016] The solvent-free polyurethane resin A described in step (3) is a polyether polyol resin structure or a polyester polyol resin structure; the solvent-free polyurethane resin B is an isocyanate prepolymer resin structure.

[0017] The solvent-free polyurethane mirror resin in step (3) is cast using an online solvent-free casting machine, which has an automatic arbitrary feeding device and can automatically stop heating when the specified temperature is reached, so that the mixing is uniform and the production efficiency is high.

[0018] The coating amounts of the waterborne polyurethane surface layer, the waterborne polyurethane middle layer and the solvent-free polyurethane bottom layer in step (4) are 50-100 g / m 2 , 70-130g / m 2 and 250-350g / m 2 .

[0019] The waterborne polyurethane surface layer and the waterborne polyurethane middle layer described in step (4) are subjected to gradient drying in sequence after coating. The gradient drying temperature is 80-100° C. and the temperature gradient is 10° C.

[0020] The base fabric in step (5) is a woven fabric, a knitted fabric or a non-woven fabric.

[0021] The high temperature drying time in step (6) is 5-10 minutes, and the high temperature drying temperature is 140°C.

[0022] Technical effects and advantages of the present invention:

[0023] 1. The preparation method of the waterborne polyurethane environmentally friendly mirror leather of the present invention is a one-step release paper transfer film method, which has high preparation efficiency and does not add any solvent in the whole preparation process, thus obtaining a solvent-free waterborne polyurethane environmentally friendly mirror leather.

[0024] 2. The surface layer is made of aliphatic polyether anionic polyurethane resin, which has good permeability and resistance to bending, excellent performance, solvent-free polyurethane mirror resin does not foam, has strong permeability, excellent bending, glass transition temperature Tg≤-15℃, and the mirror leather is glossy and translucent.

[0025] 3. The modulus of the waterborne polyurethane surface layer resin used in the present invention is 70-100KPA, the modulus of the middle layer waterborne polyurethane resin is 30-50KPA, and the modulus of the bottom layer solvent-free polyurethane resin is 70-100KPA. Only resins in the above modulus range can achieve a crease-free mirror effect. The glass transition temperature Tg≤-15°C of the resin is particularly proposed, and the key indicators of tortuosity are clearly defined, and the modulus and glass transition temperature, which are the key indicators of mirror leather effect and physical properties, are effectively combined. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a structural schematic diagram of a method for preparing waterborne polyurethane environmentally friendly mirror leather.

[0027] Figure 2 The present invention is the first preparation flow chart of the method for preparing water-based polyurethane environmentally friendly mirror leather.

[0028] Figure 3 The second preparation flow chart of the preparation method of water-based polyurethane environmentally friendly mirror leather. DETAILED DESCRIPTION

[0029] Embodiment 1:

[0030] A method for preparing waterborne polyurethane environmentally friendly mirror leather comprises the following steps:

[0031] (1) The surface layer is aliphatic polyether anionic polyurethane resin with a modulus of 100 KPa and a solid content of 40%, and a leveling agent 1, a thickener 1, and a color paste 3 are added according to the weight percentage of the resin, and mixed evenly to obtain a water-based polyurethane surface layer;

[0032] (2) The middle layer has a modulus of 30 KPa, a solid content of 40%, and a structure of aliphatic polyester polyether polyurethane resin. 0.5% of leveling agent, 1.5% of thickener, and 5% of color paste are added according to the weight percentage of the resin, and mixed evenly to obtain a water-based polyurethane middle layer;

[0033] (3) The bottom layer is a solvent-free polyurethane mirror resin with a modulus of 70 KPa, and an additive a0.2 and an additive b0.05 are added to the solvent-free polyurethane resin A100 and the solvent-free polyurethane resin B100 of the polyester polyol resin structure, and the mixture is uniformly mixed to obtain a solvent-free polyurethane bottom layer;

[0034] (4) coating a water-based polyurethane surface layer, a water-based polyurethane middle layer, and a solvent-free polyurethane bottom layer on the mirror surface of the release film in sequence, wherein the coating amounts of the water-based polyurethane surface layer, the water-based polyurethane middle layer, and the solvent-free polyurethane bottom layer are 70 g / m 2 , 100g / m 2 and 300g / m 2 After coating, the waterborne polyurethane surface layer, the waterborne polyurethane middle layer and the solvent-free polyurethane bottom layer are respectively a dry surface layer, a dry middle layer and a dry bottom layer;

[0035] The waterborne polyurethane surface layer, waterborne polyurethane middle layer and solvent-free polyurethane bottom layer after coating should be dried in a gradient manner in turn. The gradient drying temperature is 80-100℃ and the temperature gradient is 10℃.

[0036] (5) After baking at 130°C for 2 minutes, the base fabric is laminated on the bottom layer;

[0037] (6) After lamination, high temperature drying is performed for 7 minutes at a temperature of 140°C and then rolled up;

[0038] (7) After aging at room temperature for 24 hours, use a peeling paper tester to separate the product and the release film.

[0039] Embodiment 2:

[0040] A method for preparing waterborne polyurethane environmentally friendly mirror leather comprises the following steps:

[0041] (1) The surface layer is aliphatic polyether anionic polyurethane resin with a modulus of 100 KPa and a solid content of 30%, and a leveling agent 1, a thickener 1, and a color paste 3 are added according to the weight percentage of the resin, and mixed evenly to obtain a water-based polyurethane surface layer;

[0042] (2) The middle layer has a modulus of 50 KPa, a solid content of 40%, and a structure of aliphatic polyester polyether polyurethane resin. 0.5% of leveling agent, 1.5% of thickener, and 5% of color paste are added according to the weight percentage of the resin, and mixed evenly to obtain a water-based polyurethane middle layer;

[0043] (3) The bottom layer is a solvent-free polyurethane mirror resin with a modulus of 70 KPa, and an additive a0.2 and an additive b0.05 are added to the solvent-free polyurethane resin A100 and the solvent-free polyurethane resin B100 of the polyester polyol resin structure, and the mixture is uniformly mixed to obtain a solvent-free polyurethane bottom layer;

[0044] (4) coating a water-based polyurethane surface layer, a water-based polyurethane middle layer, and a solvent-free polyurethane bottom layer on the mirror surface of the release film in sequence, wherein the coating amounts of the water-based polyurethane surface layer, the water-based polyurethane middle layer, and the solvent-free polyurethane bottom layer are 70 g / m 2 , 100g / m 2 and 300g / m 2 After coating, the waterborne polyurethane surface layer, the waterborne polyurethane middle layer and the solvent-free polyurethane bottom layer are respectively a dry surface layer, a dry middle layer and a dry bottom layer;

[0045] The waterborne polyurethane surface layer, waterborne polyurethane middle layer and solvent-free polyurethane bottom layer after coating should be dried in a gradient manner in turn. The gradient drying temperature is 80-100℃ and the temperature gradient is 10℃.

[0046] (5) After baking at 130°C for 2 minutes, the base fabric is laminated on the bottom layer;

[0047] (6) After lamination, high temperature drying is performed for 7 minutes at a temperature of 140°C and then rolled up;

[0048] (7) After aging at room temperature for 24 hours, use a peeling paper tester to separate the product and the release film.

[0049] Embodiment three:

[0050] A method for preparing waterborne polyurethane environmentally friendly mirror leather comprises the following steps:

[0051] (1) The surface layer is aliphatic polyether anionic polyurethane resin with a modulus of 70 KPa and a solid content of 40%, and a leveling agent 1, a thickener 1, and a color paste 3 are added according to the weight percentage of the resin, and mixed evenly to obtain a water-based polyurethane surface layer;

[0052] (2) The middle layer has a modulus of 50 KPa, a solid content of 40%, and a structure of aliphatic polyester polyether polyurethane resin. 0.5% of leveling agent, 1.5% of thickener, and 5% of color paste are added according to the weight percentage of the resin, and mixed evenly to obtain a water-based polyurethane middle layer;

[0053] (3) The bottom layer is a solvent-free polyurethane mirror resin with a modulus of 70 KPa, and an additive a0.2 and an additive b0.05 are added to the solvent-free polyurethane resin A100 and the solvent-free polyurethane resin B100 according to the ratio of polyether polyol resin structure, and the mixture is evenly mixed to obtain a solvent-free polyurethane bottom layer;

[0054] (4) coating a water-based polyurethane surface layer, a water-based polyurethane middle layer, and a solvent-free polyurethane bottom layer on the mirror surface of the release film in sequence, wherein the coating amounts of the water-based polyurethane surface layer, the water-based polyurethane middle layer, and the solvent-free polyurethane bottom layer are 70 g / m 2 , 100g / m 2 and 300g / m 2After coating, the waterborne polyurethane surface layer, the waterborne polyurethane middle layer and the solvent-free polyurethane bottom layer are respectively a dry surface layer, a dry middle layer and a dry bottom layer;

[0055] The waterborne polyurethane surface layer, waterborne polyurethane middle layer and solvent-free polyurethane bottom layer after coating should be dried in a gradient manner in turn. The gradient drying temperature is 80-100℃ and the temperature gradient is 10℃.

[0056] (5) After baking at 130°C for 2 minutes, the base fabric is laminated on the bottom layer;

[0057] (6) After lamination, high temperature drying is performed for 7 minutes at a temperature of 140°C and then rolled up;

[0058] (7) After aging at room temperature for 24 hours, use a peeling paper tester to separate the product and the release film.

[0059] The samples manufactured in Example 1, Example 2 and Example 3 were subjected to peeling test, bending test, wear resistance and other physical property tests, and the results are shown in Table 1:

[0060] Among them, the peeling test method refers to the following standard: SATRA TM410, peeling 25-50N / 3CM;

[0061] Wear resistance test method, reference standard: ASTM D3884;

[0062] Tortuosity test method, reference standard: ISO 5402-1

[0063] It can be seen from the data in Table 1 that the mirror leather of the present invention has good peeling performance, excellent bending performance and excellent wear resistance.

[0064] Table 1

[0065]

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing waterborne polyurethane environmentally friendly mirror leather, characterized in that: The following steps are involved: (1) The surface layer is aliphatic polyether anionic polyurethane resin with a modulus of 70-100 KPa and a solid content of 20%-40%, and 0.5-1.5 of leveling agent, 0.5-1.5 of thickener, and 2-10 of color paste are added according to the weight percentage of the resin, and the mixture is evenly mixed to obtain a water-based polyurethane surface layer; (2) The middle layer has a modulus of 30-50 KPa, a solid content of 20%-40%, and a structure of aliphatic polyester polyether polyurethane resin. 0.5-1.5 of leveling agent, 0.5-1.5 of thickener, and 2-10 of color paste are added according to the weight percentage of the resin, and mixed evenly to obtain a water-based polyurethane middle layer; (3) The bottom layer is a solvent-free polyurethane mirror resin with a modulus of 70-100 KPa, the solvent-free polyurethane mirror resin includes a solvent-free polyurethane resin A and a solvent-free polyurethane resin B, and an additive a of 0.2 and an additive b of 0.05 are added according to the ratio of solvent-free polyurethane resin A 100 and solvent-free polyurethane resin B 100, and the mixture is evenly mixed to obtain a solvent-free polyurethane bottom layer; (4) coating a waterborne polyurethane surface layer, a waterborne polyurethane middle layer and a solvent-free polyurethane bottom layer on the mirror surface of the release film in sequence, wherein the waterborne polyurethane surface layer, the waterborne polyurethane middle layer and the solvent-free polyurethane bottom layer after coating are a dry surface layer, a dry middle layer and a dry bottom layer in sequence; (5) After baking at 130°C for 1.5-2 minutes, the base fabric is laminated on the bottom layer; (6) After lamination, high temperature drying and rolling; (7) After aging at room temperature for 24 hours, use a peeling paper tester to separate the product and the release film.

2. The method for preparing the waterborne polyurethane environmentally friendly mirror leather according to claim 1, characterized in that: The viscosity of the waterborne polyurethane surface layer in step (1) is adjusted to 500-1500 CPS.

3. The method for preparing the waterborne polyurethane environmentally friendly mirror leather according to claim 1, characterized in that: The VOC of the leveling agent, thickener and color paste described in step (2) is less than 50PPM.

4. The method for preparing the waterborne polyurethane environmentally friendly mirror leather according to claim 1, characterized in that: The viscosity of the waterborne polyurethane intermediate layer in step (2) is adjusted to 500-1500 CPS.

5. The method for preparing the waterborne polyurethane environmentally friendly mirror leather according to claim 1, characterized in that: The solvent-free polyurethane resin A described in step (3) is a polyether polyol resin structure or a polyester polyol resin structure; the solvent-free polyurethane resin B is an isocyanate prepolymer resin structure.

6. The method for preparing the environmentally friendly waterborne polyurethane mirror leather according to claim 1, characterized in that: The solvent-free polyurethane mirror resin in step (3) is cast using an online solvent-free casting machine.

7. The method for preparing the waterborne polyurethane environmentally friendly mirror leather according to claim 1, characterized in that: The coating amounts of the waterborne polyurethane surface layer, the waterborne polyurethane middle layer and the solvent-free polyurethane bottom layer in step (4) are 50-100 g / m 2 , 70-130g / m 2 and 250-350g / m 2 .

8. The method for preparing the environmentally friendly waterborne polyurethane mirror leather according to claim 1, characterized in that: The waterborne polyurethane surface layer and the waterborne polyurethane middle layer described in step (4) are subjected to gradient drying in sequence after coating. The gradient drying temperature is 80-100° C. and the temperature gradient is 10° C.

9. The method for preparing the waterborne polyurethane environmentally friendly mirror leather according to claim 1, characterized in that: The base fabric in step (5) is a woven fabric, a knitted fabric or a non-woven fabric.

10. The method for preparing the environmentally friendly waterborne polyurethane mirror leather according to claim 1, characterized in that: The high temperature drying time in step (6) is 5-10 minutes, and the high temperature drying temperature is 140°C.

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