Environmentally friendly multifunctional artificial leather material and preparation method thereof

Abstract

The present invention relates to the field of polymer composite materials, and discloses an environmentally friendly multifunctional artificial leather material and a preparation method thereof. A water-based polyurethane, a micro-foaming agent, a dispersant, a cross-linking agent and a modified ZnO@SiO2 are mixed to form a main mixture, which is coated on a polyester knitted fabric and subjected to static precipitation and thermal foaming treatment to obtain a finished product. A modified ZnO@SiO2 mixed system is prepared by a specific process, and ZnO nanoparticles are first prepared and then composite-modified. The present invention adopts water-based polyurethane, which significantly reduces the release of volatile substances such as VOCs compared to traditional materials and is more environmentally friendly; the unique formula and process give the material properties such as high temperature resistance, UV protection, waterproofness, and breathability. By dispersing and modifying the ZnO nanoparticles and allowing the modified substance to form a dense protective layer on the outer layer of the coating through static precipitation, the comprehensive performance of the material is further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer composite materials, and particularly relates to an environmentally friendly multifunctional artificial leather material and a preparation method thereof. Background Art

[0002] As an alternative to natural leather, artificial leather is widely used across various industries due to its advantages, including high production efficiency, low cost, and controllable appearance. However, with the continuous improvement of global environmental standards, the use of organic solvents and VOC emissions in the production of traditional artificial leather are gaining increasing attention. Traditional artificial leather materials are primarily based on polyurethane resins containing organic solvents. During processing and use, they release large amounts of volatile organic compounds (VOCs), posing a potential threat to human health and the environment.

[0003] Furthermore, ordinary artificial leather materials generally suffer from poor temperature resistance. They are susceptible to heat aging, becoming hard or brittle, and losing flexibility during use, making them unsuitable for high-temperature environments. This severely limits their use cases. Furthermore, due to their insufficient breathability and low comfort, traditional artificial leather is unsuitable for high-end furniture and automotive interior applications, such as seat coverings and wall coverings, which require high tactile and breathability qualities. This also limits their adoption in high-end settings.

[0004] Therefore, in an era of surging demand for leather, the development of an artificial leather material that has low VOCs emissions, high temperature resistance, UV protection, waterproofness, and good breathability has become an urgent need in the industry. Summary of the Invention

[0005] To address the shortcomings of the aforementioned prior art, the present invention provides an environmentally friendly, multifunctional artificial leather material and a method for preparing the same. This method utilizes waterborne polyurethane to prepare the artificial leather material, effectively reducing the release of volatile organic compounds (VOCs) and other volatile substances compared to conventional artificial leather, significantly enhancing its environmental friendliness. Furthermore, a formulation comprising a mixture of waterborne polyurethane, a microfoaming agent, a dispersant, a crosslinking agent, and a modified ZnO@SiO2 system has been developed to achieve properties such as high-temperature resistance, UV protection, water resistance, and excellent breathability.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] Provided is a method for preparing an environmentally friendly multifunctional artificial leather material, the method comprising the following steps:

[0008] S11, preparing the main mixture: weighing corresponding parts by mass of water-based polyurethane, micro-foaming agent, dispersant, cross-linking agent and modified ZnO@SiO2 mixed system, placing them in a high-speed mixer and mixing them evenly to form a main mixture;

[0009] S12, preparing a foamed composite layer: weighing a polyester knitted fabric of a corresponding mass percentage, and coating the main mixture described in step S11 on the surface of the polyester knitted fabric using a coating machine, with a coating thickness of 1 mm, a coating speed of 20 mm / min, and a temperature of 25° C., to form a foamed composite layer;

[0010] S13, standing and settling: the coating layer of the foamed composite layer prepared in step S12 is placed downward and allowed to stand for 10 minutes;

[0011] S14, thermal foaming treatment: placing the foamed composite layer in step S13 into a hot air drying tunnel at a temperature of 100° C. for 30 minutes to form a porous soft middle layer and solidify the surface structure to obtain an environmentally friendly artificial leather product.

[0012] The invention is further preferred as a preparation method of an environmentally friendly multifunctional artificial leather material.

[0013] Preferably, the amounts of waterborne polyurethane, microfoaming agent, dispersant, crosslinking agent, modified ZnO@SiO2 mixed system and polyester knitted fabric are: 80 parts by mass, 2 parts by mass, 50 parts by mass, 0.5 parts by mass, 10-15 parts by mass, and 100 parts by mass, respectively;

[0014] Preferably, the solid content of the waterborne polyurethane is: 35%;

[0015] Preferably, the microfoaming agent is: sodium bicarbonate, purity 99.9%;

[0016] Preferably, the dispersant is: deionized water;

[0017] Preferably, the cross-linking agent is isophorone diisocyanate with a purity of 99.9%.

[0018] Preferably, the preparation method of the modified ZnO@SiO2 mixed system comprises the following steps:

[0019] S21. Preparation of a modified ZnO@SiO2 mixed system: tetraethyl orthosilicate, anhydrous ethanol, deionized water I and nitric acid were weighed, reacted in a water bath at 60°C for 3 h, then allowed to stand at room temperature for 24 h, deionized water II was added, and the mixture was heated to 85°C to evaporate the anhydrous ethanol and nitric acid, and then sodium lauryl sulfate was added. ZnO nanoparticles with an average particle size of 4.5 nm were dispersed into the SiO2 aqueous solution by a high-speed disperser, and hexamethyldiazamethane was added and stirred by a disperser for 15 min, and then allowed to stand for aging for 1 day to obtain a modified ZnO@SiO2 mixed system.

[0020] Preferably, the added amounts of tetraethyl orthosilicate, anhydrous ethanol, deionized water I, nitric acid, deionized water II, sodium lauryl sulfate, ZnO nanoparticles and hexamethyldiazaalkane described in step S21 are: 15 mass parts, 40 mass parts, 1 mass part, 0.5 mass parts, 100 mass parts, 0.1 mass parts, 1 mass part and 0.2 mass parts, respectively.

[0021] Preferably, the stirring speed of the high-speed disperser in step S22 is 2000 rpm / min.

[0022] An environmentally friendly multifunctional artificial leather material is prepared according to the preparation method.

[0023] The beneficial effects of the present invention compared to the prior art are:

[0024] (1) The present invention uses waterborne polyurethane to prepare artificial leather materials, effectively reducing the release of volatile organic compounds (VOCs) and other volatile substances compared to the original artificial leather, thereby significantly improving its environmental friendliness. Furthermore, by studying the formulation and process of a mixed system of waterborne polyurethane, a microfoaming agent, a dispersant, a crosslinking agent, and a modified ZnO@SiO2, the artificial leather material exhibits properties such as high temperature resistance, UV protection, water resistance, and good air permeability.

[0025] (2) The present invention adds ZnO nanoparticles with an average particle size of 4.5 nm to the system. The particles absorb ultraviolet light and can be converted into visible light, thereby avoiding heat rise. However, particles of this particle size are very easy to agglomerate. In the present invention, a surfactant is added to the system and high-speed dispersion is performed to disperse the ZnO nanoparticles in the SiO2 system, and a modified ZnO@SiO2 mixed system is obtained by modification.

[0026] (3) The present invention precipitates the modified ZnO@SiO2 on the outer layer of the coating by static precipitation, and then heats and solidifies it to form a denser protective layer on the outermost layer, thereby having better high temperature resistance, UV protection, and waterproof performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a cross-sectional SEM image of the environmentally friendly multifunctional artificial leather material obtained in Example 1;

[0028] Figure 2 is a TEM image of the modified ZnO@SiO2 mixed system prepared in Example 1;

[0029] Figure 3 is a graph of VOC emissions over 72 hours for Examples 1-3 and Comparative Example 2;

[0030] Figure 4 is the absorbance spectrum of Examples 1-3, Comparative Example 1 and Comparative Example 4;

[0031] Figure 5 is the fluorescence emission spectra of Examples 1-3 and Comparative Example 1;

[0032] Figure 6 is the elongation of Examples 1-3 and Comparative Example 1 after heat treatment at 150°C;

[0033] Figure 7 is the air permeability value of Examples 1-3 and Comparative Example 3;

[0034] Figure 8 It is the water contact angle of Examples 1-3, Comparative Example 1 and Comparative Example 4. DETAILED DESCRIPTION

[0035] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is given in conjunction with the following embodiments. The following is merely an example and illustration of the concept of the present invention. Those skilled in the art may make various modifications, additions, or substitute similar methods for the specific embodiments described. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they shall fall within the scope of protection of the present invention.

[0036] The above preparation method of the present invention is described below through specific examples and comparative examples. Example 1

[0037] This embodiment provides an environmentally friendly multifunctional artificial leather material and a preparation method thereof, and the preparation steps are as follows:

[0038] S11, preparing a main mixture: weighing 80 parts by mass of waterborne polyurethane, 2 parts by mass of micro-foaming agent, 50 parts by mass of dispersant, 0.5 parts by mass of cross-linking agent and 10 parts by mass of modified ZnO@SiO2 mixed system, placing them in a high-speed blender and mixing them evenly to form a main mixture;

[0039] S12, preparing a foamed composite layer: weighing 100 parts by mass of polyester knitted fabric, and coating the main mixture described in step S11 on the surface of the polyester knitted fabric using a coating machine, with a coating thickness of 1 mm, a coating speed of 20 mm / min, and a temperature of 25° C., to form a foamed composite layer;

[0040] S13, standing and settling: the coating layer of the foamed composite layer prepared in step S12 is placed downward and allowed to stand for 10 minutes;

[0041] S14, thermal foaming treatment: placing the foamed composite layer in step S13 into a hot air drying tunnel at a temperature of 100° C. for 30 minutes to form a porous soft middle layer and solidify the surface structure to obtain an environmentally friendly artificial leather product.

[0042] In addition, the solid content of the waterborne polyurethane is: 35%;

[0043] The microfoaming agent is: sodium bicarbonate, purity 99.9%;

[0044] The dispersant is: deionized water;

[0045] The cross-linking agent is isophorone diisocyanate with a purity of 99.9%.

[0046] An environmentally friendly multifunctional artificial leather material is obtained through the preparation method.

[0047] The preparation method of the modified ZnO@SiO2 mixed system comprises the following steps:

[0048] S21. Preparation of a modified ZnO@SiO2 mixed system: Weigh 15 parts by mass of tetraethyl orthosilicate, 40 parts by mass of anhydrous ethanol, 1 part by mass of deionized water I and 0.5 parts by mass of nitric acid, react in a water bath at 60°C for 3 hours, then let it stand at room temperature for 24 hours, add 100 parts by mass of deionized water II, heat to 85°C, evaporate to remove anhydrous ethanol and nitric acid, then add 0.1 parts by mass of sodium lauryl sulfate, and then disperse 1 part by mass of ZnO nanoparticles with an average particle size of 4.5 nm into the SiO2 aqueous solution through a 2000 rpm high-speed disperser, then add 0.2 parts by mass of hexamethyldiazapine and stir through a disperser for 15 minutes, then let it stand and age for 1 day to obtain a modified ZnO@SiO2 mixed system. Example 2

[0049] The difference between this embodiment and embodiment 1 is that the amount of the modified ZnO@SiO2 mixed system in step S11 is 12 parts by mass. Example 3

[0050] The difference between this embodiment and embodiment 1 is that the amount of the modified ZnO@SiO2 mixed system in step S11 is 15 parts by mass. Comparative Example 1

[0051] The difference between this comparative example and Example 1 is that no modified ZnO@SiO2 mixed system is added. Comparative Example 2

[0052] The difference between this comparative example and Example 1 is that the added main material is solvent-based polyurethane. Comparative Example 3

[0053] The difference between this comparative example and Example 1 is that no microfoaming agent is added in the process of step S11. Comparative Example 4

[0054] The difference between this comparative example and Example 1 is that step S13 is not performed.

[0055] Figure 1 This is a cross-sectional SEM image of the environmentally friendly multifunctional artificial leather material produced in Example 1. Numerous pores can be seen within the material, while the interface is significantly denser than the interior. This demonstrates that the structure offers excellent air permeability, while the dense interface improves the material's resistance to high temperatures, UV rays, and water.

[0056] Figure 2 This is a TEM image of the modified ZnO@SiO2 mixed system prepared in Example 1. It can be seen that the method of this invention can produce a modified ZnO@SiO2 mixed system with good dispersion. Other experimental methods have also been explored, such as directly adding ZnO, where the acid in the SiO2 system reacts with the ZnO. Without the surfactant sodium dodecyl sulfate, the addition of ZnO nanoparticles produces precipitation.

[0057] Figure 3 This is a graph of the VOC emission of Examples 1-3 and Comparative Example 2 over a period of 72 hours. It can be seen that the VOC emission of all Examples is lower than that of the Comparative Example. Therefore, it is believed that the VOC emission of this formula is lower than that of traditional artificial leather and has better environmental protection.

[0058] Figure 4 These are the absorbance spectra of Examples 1-3, Comparative Example 1 and Comparative Example 4; it can be seen that the materials of Examples 1-3 have stronger ability to absorb ultraviolet rays and have better resistance to ultraviolet aging, which is because the ZnO material absorbs ultraviolet light.

[0059] Figure 5 It is the fluorescence emission spectrum of Examples 1-3 and Comparative Example 1; the fluorescence spectrum shows that ZnO nanoparticles can not only absorb ultraviolet light, but also convert ultraviolet light into visible light, thereby reducing the conversion of ultraviolet light absorbed by ZnO into heat and increasing the service life of the material.

[0060] Figure 6 It is the elongation of Examples 1-3, Comparative Example 1 and Comparative Example 4 after heat treatment at 150°C; it can be seen that Examples 1-3 have better high temperature resistance than the comparative examples.

[0061] Figure 7 It is the air permeability value of Examples 1-3 and Comparative Example 3; it can be seen that the air permeability of Examples 1-3 is better than that of Comparative Example 3.

[0062] Figure 8The water contact angles of Examples 1-3, Comparative Example 1, and Comparative Example 4 are shown. The water contact angles show that Examples 1-3 have higher water contact angles, indicating that water droplets roll off the material surface more easily, thereby improving the waterproof performance of the artificial leather material. In addition, Comparative Example 4 shows that step S13 of the embodiment is not performed, resulting in less deposition of the modified ZnO@SiO2 mixed system at the interface, resulting in a smaller water contact angle.

[0063] In addition, from Figure 4 、 Figure 6 and Figure 8 It can be concluded that the present invention precipitates the modified ZnO@SiO2 on the outer layer of the coating by static precipitation, and then heats and solidifies it to form a denser protective layer on the outermost layer, thereby having better high temperature resistance, UV protection, and waterproof performance.

[0064] In summary, the environmentally friendly multifunctional artificial leather material prepared by the present invention has low VOC emissions and low volatile matter content, resulting in enhanced environmental friendliness. Furthermore, the environmentally friendly multifunctional artificial leather material exhibits excellent properties such as high-temperature resistance, UV protection, water resistance, and breathability, ensuring excellent performance while maintaining environmental friendliness, making it suitable for use in the high-end leather industry.

Claims

1. A method for preparing an environmentally friendly multifunctional artificial leather material, characterized in that: The method comprises the following steps: S11, preparing the main mixture: weighing corresponding parts by mass of water-based polyurethane, micro-foaming agent, dispersant, cross-linking agent and modified ZnO@SiO2 mixed system, placing them in a high-speed mixer and mixing them evenly to form a main mixture; S12, preparing a foamed composite layer: weighing a polyester knitted fabric of a corresponding mass percentage, and coating the main mixture described in step S11 on the surface of the polyester knitted fabric using a coating machine, with a coating thickness of 1 mm, a coating speed of 20 mm / min, and a temperature of 25° C., to form a foamed composite layer; S13, standing and settling: the coating layer of the foamed composite layer prepared in step S12 is placed downward and allowed to stand for 10 minutes; S14, thermal foaming treatment: placing the foamed composite layer in step S13 into a hot air drying tunnel at a temperature of 100° C. for 30 minutes to form a porous soft middle layer and solidify the surface structure to obtain an environmentally friendly artificial leather product; The method for preparing the modified ZnO@SiO2 mixed system in step S11 comprises the following steps: S21. Preparation of a modified ZnO@SiO2 mixed system: tetraethyl orthosilicate, anhydrous ethanol, deionized water I and nitric acid were weighed, reacted in a water bath at 60°C for 3 h, then allowed to stand at room temperature for 24 h, deionized water II was added, and the mixture was heated to 85°C to evaporate the anhydrous ethanol and nitric acid, and then sodium lauryl sulfate was added. ZnO nanoparticles with an average particle size of 4.5 nm were dispersed into the SiO2 aqueous solution by a high-speed disperser, and hexamethyldiazamethane was added and stirred by a disperser for 15 min, and then allowed to stand for aging for 1 day to obtain a modified ZnO@SiO2 mixed system.

2. The method for preparing the environmentally friendly multifunctional artificial leather material according to claim 1, characterized in that: The amounts of waterborne polyurethane, micro-foaming agent, dispersant, cross-linking agent, modified ZnO@SiO2 mixed system and polyester knitted fabric are 80 parts by mass, 2 parts by mass, 50 parts by mass, 0.5 parts by mass, 10-15 parts by mass, and 100 parts by mass, respectively; The solid content of the waterborne polyurethane is: 35%; The microfoaming agent is: sodium bicarbonate, purity 99.9%; The dispersant is: deionized water; The cross-linking agent is isophorone diisocyanate with a purity of 99.9%.

3. The method for preparing the environment-friendly multifunctional artificial leather material according to claim 1, characterized in that: In the preparation method of the modified ZnO@SiO2 mixed system, the added amounts of tetraethyl orthosilicate, anhydrous ethanol, deionized water I, nitric acid, deionized water II, sodium lauryl sulfate, ZnO nanoparticles, and hexamethyldiazapine described in step S21 are: 15 mass parts, 40 mass parts, 1 mass part, 0.5 mass parts, 100 mass parts, 0.1 mass parts, 1 mass part, and 0.2 mass parts, respectively.

4. The method for preparing the environment-friendly multifunctional artificial leather material according to claim 1, characterized in that: In the preparation method of the modified ZnO@SiO2 mixed system, the stirring speed of the high-speed disperser in step S21 is 2000 rpm / min.

5. An environmentally friendly multifunctional artificial leather material prepared by the preparation method according to any one of claims 1 to 4.

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