Electroless refrigeration leather and preparation process thereof

Abstract

The invention relates to non-electric refrigerating leather and a preparation process. The leather is formed by stacking an antifouling layer, an anti-aging layer, a refrigerating layer, a reflecting layer and a leather base cloth layer. By adding the composite cooling powder into the refrigeration layer, the infrared radiance of an atmosphere window wave band is remarkably improved, the leather surface temperature is effectively reduced, the reflecting layer uses particles compounded with high and low refractive indexes to construct a scattering interface, sunlight is efficiently reflected, the leather temperature is jointly reduced in cooperation with infrared radiation, and the problem of surface temperature accumulation of black leather is solved. The anti-aging layer is used for protecting the leather and preventing the service life of the leather from being shortened due to ultraviolet irradiation, and the thickness of each layer is optimally designed, so that the leather has excellent cooling effect, wear-resistant color fastness and aging resistance.

Description

Technical Field

[0001] This invention relates to the field of leather materials, and in particular to an electrically cooled leather and its preparation process. Background Technology

[0002] Traditional leather, especially when used in automotive interiors, outdoor seats, and frequently touched everyday items, generally suffers from two major technical shortcomings: First, its surface abrasion resistance and colorfastness are relatively low, and it is prone to wear and fading after long-term use, affecting its appearance and lifespan; second, in high-temperature environments, such as vehicles parked outdoors in summer or outdoor facilities, especially black leather, the surface absorbs heat significantly. In tropical and subtropical regions with high temperatures and radiation, the measured surface temperature can reach over 100°C. This not only easily causes contact burns to the human body, but also accelerates the aging process of the leather material, leading to hardening, cracking, and fading, seriously restricting its applicability and safety and comfort in high-temperature scenarios.

[0003] In summary, traditional leather has the following technical defects: black leather has a low solar reflectance and infrared emissivity, which makes it easy for heat to accumulate on the surface, resulting in a shortened service life and reduced abrasion resistance and color fastness. Summary of the Invention

[0004] This invention mainly proposes an electro-cooled leather and its preparation process, aiming to solve the problems of low solar reflectance and infrared emissivity of black leather in the prior art, excessively high surface temperature during use, short service life and poor abrasion resistance and color fastness.

[0005] One aspect of this invention is a non-electrically cooled leather, which is composed of an anti-fouling layer, an anti-aging layer, a cooling layer, a reflective layer, and a leather base fabric layer stacked together; The cooling layer comprises, by weight, 350-500 parts of waterborne polyurethane resin, 15-25 parts of crosslinking agent, 200-300 parts of composite cooling powder, 3-6 parts of leveling agent, 15-25 parts of dispersant, 8-12 parts of silane coupling agent, 1-3 parts of defoamer, 45-100 parts of pigment powder, and 80-120 parts of deionized water.

[0006] The cooling layer can effectively reduce the temperature of the leather. The composite cooling powder has a high infrared emissivity, which can emit infrared light radiation, thereby reducing the temperature of the leather.

[0007] Preferably, the composite cooling powder comprises, by mass parts: 60-80 parts CuFe2O4, 40-60 parts La2O3, 40-60 parts Yb2O3, 40-60 parts Al2O3 and 20-30 parts Cr2O3.

[0008] The composite cooling powder is made up of multiple materials that work together to increase the intensity of infrared radiation and the accuracy of the atmospheric window (8-13μm), thereby improving infrared radiation efficiency and effectively reducing the surface temperature of leather.

[0009] Preferably, the pigment powder comprises 35-70 parts Fe3O4, 10-20 parts MnO2, and 3-8 parts MgO by mass.

[0010] Pigment powder is a material that can color leather black, and MnO2 and MgO in it can work with the reflective layer to reflect sunlight and heat, thereby improving the problem of black leather absorbing more heat and having a higher surface temperature.

[0011] Preferably, the reflective layer comprises, by mass parts: 80-120 parts deionized water, 5-10 parts leveling agent, 20-30 parts dispersant, 400-600 parts waterborne polyurethane resin, 3-6 parts crosslinking agent, and 60-110 parts refractive particles.

[0012] The reflective layer contains refracting particles that can reflect most of the sunlight back, preventing heat from entering the leather and further reducing the leather's temperature.

[0013] Preferably, the refracting particles include high refractive index particles with a refractive index > 2 and low refractive index particles with a refractive index < 1.6; The high refractive index particles include: 20-30 parts TiO2, 5-10 parts ZrO2, 8-10 parts SiC, 6-8 parts Si3N4, and 8-10 parts ZnSe; The low refractive index particles include: 10-20 parts of BaSO4, 3-8 parts of SiO2, and 3-8 parts of CaCO3.

[0014] The reflective layer contains both high-refractive-index particles (refractive index > 2) and low-refractive-index particles (refractive index < 1.6), which can create a large number of refractive interfaces, increase the number of scattering events within the interfaces, and reduce the penetration power of sunlight.

[0015] Preferably, the anti-aging layer comprises, by weight, 80-120 parts of waterborne polyurethane resin and 1-5 parts of ultraviolet blocking agent.

[0016] The anti-aging layer can block ultraviolet rays, preventing them from penetrating and damaging the leather, and can significantly extend the lifespan of the leather.

[0017] Preferably, the antifouling layer comprises, by weight, 80-120 parts of waterborne polyurethane resin, 1-5 parts of silica, and 0.1-0.5 parts of antifouling additive.

[0018] The anti-fouling layer is the outermost layer of the leather, making the leather surface less prone to dirt and easy to clean, ensuring the long-term performance of the underlying material.

[0019] Preferably, the thickness of the anti-fouling layer is 10-15 μm, the thickness of the anti-aging layer is 25-30 μm, the thickness of the cooling layer is 50-300 μm, and the thickness of the reflective layer is 80-200 μm.

[0020] The thickness of the anti-fouling and anti-aging layers forms a complete and dense protective film, maintaining good transparency and showcasing the original color of the leather. The cooling and reflective layers are relatively thick, effectively preventing direct light penetration and increasing infrared emissivity and solar reflectance.

[0021] On the other hand, a process for preparing non-electrically cooled leather is proposed, the process including: S1. Preparation of the cooling layer: First, the leveling agent and the dispersant are mixed evenly, and then the composite cooling powder is added and stirred to disperse. Then, the waterborne polyurethane resin, the silane coupling agent, the pigment powder and the defoamer are added and stirred evenly to obtain the waterborne polyurethane cooling slurry. After crosslinking with the crosslinking agent, the water-based polyurethane cooling slurry is coated to prepare a cooling layer. S2. Preparation of the reflective layer: First, the leveling agent and the dispersant are stirred and mixed, then the refractive particles are added and stirred and dispersed, and then the waterborne polyurethane resin and the crosslinking agent are added and mixed to obtain a waterborne polyurethane reflective functional slurry; The reflective layer is obtained by coating the water-based polyurethane resin reflective slurry onto the cooling layer.

[0022] S3. Prepare the anti-aging layer: The waterborne polyurethane resin and the ultraviolet blocker are mixed and then coated onto the cooling layer to obtain the anti-aging layer. S4. Preparation of antifouling layer: The water-based polyurethane resin, the silica and the antifouling additive are mixed and then prepared in the anti-aging layer to obtain the antifouling layer; S5. Preparation of the leather base fabric layer: The leather base layer is obtained by coating the reflective layer with at least one of woven fabric, knitted fabric, nonwoven fabric and composite fabric, thereby obtaining the complete electrically refrigerated leather. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Appendix Figure 1 Side view of non-electrically cooled leather.

[0025] In the attached diagram: 1-Anti-fouling layer, 2-Anti-aging layer, 3-Cooling layer, 4-Reflective layer, 5-Leather base fabric layer. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other. At the same time, the raw materials mentioned below, unless otherwise specified, are all commercially available products; the process steps or preparation methods not mentioned in detail are all process steps or preparation methods known to those skilled in the art.

[0027] Preparation method of non-electrically cooled leather: S1, Cooling Layer: First, weigh 80-120 g of deionized water, then add 3-6 g of leveling agent (TEGO 410) and 15-25 g of dispersant (sodium polyacrylate). Stir and mix for 2 minutes, then pour in 200-300 g of composite cooling powder. Disperse at high speed for 30 minutes, then add 350-500 g of waterborne polyurethane resin, 8-12 g of silane coupling agent (γ-(2,3-epoxypropoxy)propyltrimethoxysilane), 45-100 g of pigment powder, and 1-3 g of defoamer (TEGO Foamex) in sequence. Continue stirring and dispersing for 20 minutes to obtain waterborne polyurethane cooling slurry.

[0028] The composite cooling powder includes 60-80 g CuFe2O4, 40-60 g La2O3, 40-60 g Yb2O3, 40-60 g Al2O3, and 20-30 g Cr2O3. The pigment powder includes 35-70 g Fe3O4, 10-20 g MnO2, and 3-8 g MgO.

[0029] Add 15-25 g of crosslinking agent (aziridine) to the water-based polyurethane cooling slurry, stir for 10 minutes, filter through a 200-mesh filter, and then apply the coating. Control the wet film thickness so that the coating thickness reaches 50-300 μm after drying and curing. Then bake at 80-100 ℃ for 5 minutes to cure and form a cooling layer.

[0030] The cooling layer of this invention achieves highly efficient non-electrical radiation cooling by introducing a composite cooling powder. This cooling powder is composed of multiple functional materials working synergistically: on the one hand, rare earth oxides (La2O3, Yb2O3) and transition metal oxides (CuFe2O4) are combined to significantly improve the infrared emissivity of the coating in the atmospheric window (8~13μm) band, ensuring efficient heat radiation; on the other hand, materials such as Al2O3 and Cr2O3 enhance the structural stability and spectral selectivity of the coating. This multi-component synergistic effect ensures infrared emission intensity while also improving the accuracy of the emission band, thereby maximizing radiative heat dissipation efficiency and significantly reducing the surface temperature of the leather.

[0031] Addressing the industry pain point of black leather's tendency to absorb heat, this invention introduces functional inorganic materials such as MnO2 and MgO into the pigment powder. This reduces the absorption of sunlight and allows heat to be efficiently radiated away with the help of a reflective layer. Therefore, the pigment powder, combined with a composite cooling powder, effectively solves the problem of increased surface temperature caused by heat absorption in traditional black leather. Furthermore, the cooling layer utilizes a silane coupling agent to enhance material performance, and combined with anti-fouling and anti-aging layers, extends the lifespan of the leather and achieves a colorfastness rating of 5.

[0032] S2. Preparation of the reflective layer: First, weigh 80-120 g of deionized water, then add 5-10 g of leveling agent (TEGO 410) and 20-30 g of dispersant (sodium polyacrylate). Stir and mix for 2 minutes. Then, add the following refractive particles: 3-8 g SiO2, 20-30 g TiO2, 5-10 g ZrO2, 10-20 g BaSO4, 8-10 g SiC, 6-8 g Si3N4, 8-10 g ZnSe, and 3-8 g CaCO3. Disperse at high speed for 30 minutes. Next, add 400-600 g of waterborne polyurethane resin and 3-6 g of crosslinking agent (aziridine). Continue stirring and dispersing for 20 minutes to obtain the waterborne polyurethane reflective functional slurry. Then, coat the waterborne polyurethane reflective functional slurry onto the cooling layer to a thickness of 80-100 μm. Finally, bake at 120 ℃ for 8 minutes to dry and cure, forming the reflective layer.

[0033] By utilizing the optical contrast of high and low refractive index particles to construct a dense scattering network, the combination of high and low refractive index particles can increase the refraction path of sunlight, increase the scattering of sunlight, and reduce the refraction intensity of sunlight, thereby reducing the absorption of leather and increasing the probability of it being reflected back to the outside.

[0034] The reflective layer works in conjunction with the cooling layer, radiating infrared light while reflecting sunlight. In addition, the reflective layer can further radiate the infrared light that is not fully radiated in the cooling layer, thereby improving radiation efficiency and reducing the heat absorbed by the leather.

[0035] S3. Prepare the anti-aging layer: Mix 80-120 g of waterborne polyurethane resin and 1-5 g of UV blocker (either benzimidazole sulfonic acid or benzophenone), apply the mixture to the cooling layer with a thickness of 25 μm, and then bake at 120 ℃ for 8 minutes to dry and cure to form an anti-aging layer.

[0036] The anti-aging layer can block ultraviolet rays, preventing them from penetrating and damaging the leather, and can significantly extend the lifespan of the leather.

[0037] S4. Prepare the antifouling layer: Mix 80-120 g of waterborne polyurethane resin, 1-5 g of silica and 0.1-0.5 g of antifouling additive (hydroxyl silicone oil), apply the mixture to the anti-aging layer with a coating thickness of 10 μm, and then bake at 120 ℃ for 8 minutes to dry and cure to form an antifouling layer.

[0038] The thickness of the anti-fouling layer and the anti-aging layer is just right to form a complete and dense protective film, maintaining good transparency, reflecting the original color of the leather, and protecting the leather together with the anti-aging layer.

[0039] S5. Preparation of leather base fabric: At least one of woven, knitted, nonwoven, and composite fabrics is coated onto the reflective layer to form the base fabric, with a coating thickness of 165–235 μm. The final product is an electrically cooled leather prepared by layering an anti-fouling layer, an anti-aging layer, a cooling layer, a reflective layer, and a base fabric layer.

[0040] Using woven fabric as the leather's framework enhances the leather's feel while also increasing its tensile and tear resistance.

[0041] Detection method: Infrared emissivity test: Tested using a Fourier transform infrared spectrometer according to GB / T 30127~2013.

[0042] Solar reflectance test: JG / T 235~2014 standard uses an ultraviolet-visible-near-infrared spectrophotometer for testing.

[0043] Service life test: The test standard is based on the accelerated aging method of artificial climate in GB / T 18244~2022, and the aging test is conducted using fluorescent ultraviolet lamps. The upper limit of the test time is 500 hours.

[0044] Color fastness to abrasion: Color fastness to abrasion was tested according to GB / T 39366-2020.

[0045] Surface temperature test: The leather surface temperature was measured after being exposed to a simulated solar light source for a certain period of time. 1. Test lamp source: PHILIPS, 375W CH IR2 230-250V; 2. Temperature measuring equipment: YOWEXA digital display four-channel thermocouple with a resolution of 0.01℃; 3. The test light source probe is positioned on the leather surface; 4. The straight-line distance between the test light and the leather is 80cm; 5. Simulated lamp illumination time: 15 minutes.

[0046] Example 1 S1. Preparation of the cooling layer: First, weigh 100 g of deionized water, then add 5 g of leveling agent TEGO 410 and 20 g of sodium polyacrylate and stir for 2 minutes. Then, pour in 250 g of composite cooling powder and disperse at high speed for 30 minutes. Next, add 400 g of waterborne polyurethane resin, 10 g of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, 55 g of pigment powder and 2 g of defoamer TEGOFoamex 810 in sequence, and continue stirring and dispersing for 20 minutes to obtain waterborne polyurethane cooling slurry.

[0047] The composite cooling powder includes 75 g CuFe2O4, 50 g La2O3, 50 g Yb2O3, 50 g Al2O3 and 25 g Cr2O3.

[0048] The pigment powder includes: 35 g Fe3O4, 10 g MnO2 and 10 g MgO.

[0049] After adding 20 g of aziridine to the waterborne polyurethane cooling slurry and stirring for 10 minutes, the mixture was filtered through a 200-mesh filter and then coated. The appropriate wet film thickness was controlled to ensure that the coating thickness was 100 μm after drying and curing. The coating was then baked at 120 °C for 8 minutes to dry and cure, forming a cooling layer.

[0050] S2. Preparation of the reflective layer: First, weigh 100 g of deionized water, then add 8 g of leveling agent TEGO 410 and 25 g of sodium polyacrylate and stir for 2 minutes. Next, add 5 g of SiO2, 30 g of TiO2, 6 g of ZrO2, 15 g of BaSO4, 8 g of SiC, 6 g of Si3N4, 8 g of ZnSe, and 5 g of CaCO3, and disperse at high speed for 30 minutes. Then, add 500 g of waterborne polyurethane resin and 4 g of aziridine, and continue stirring and dispersing for 20 minutes to obtain a waterborne polyurethane reflective functional slurry. Finally, coat the waterborne polyurethane reflective functional slurry onto the cooling layer to a thickness of 100 μm, and then bake at 120℃ for 8 minutes to dry and cure, forming a reflective layer.

[0051] S3. Prepare the anti-aging layer: 100 g of waterborne polyurethane resin and 4 g of benzimidazole sulfonic acid were stirred and mixed, and then coated on the cooling layer with a coating thickness of 25 μm. The mixture was then baked at 120°C for 8 minutes to dry and cure, forming an anti-aging layer.

[0052] S4. Prepare the antifouling layer: Mix 100 g of waterborne polyurethane resin, 2 g of silica and 0.2 g of hydroxyl silicone oil, apply the mixture to the anti-aging layer with a thickness of 10 μm, and then bake at 120°C for 8 minutes to dry and cure to form an anti-fouling layer.

[0053] S5. Preparation of leather base fabric: At least one of woven fabric, knitted fabric, nonwoven fabric, and composite fabric is coated onto the reflective layer to a thickness of 235 μm. The final product is an electrically cooled leather prepared by layering an anti-fouling layer, an anti-aging layer, a cooling layer, a reflective layer, and a leather base fabric.

[0054] Example 2 S1. Preparation of the cooling layer: First, weigh 100 g of deionized water, then add 5 g of leveling agent TEGO 410 and 20 g of sodium polyacrylate and stir for 2 minutes. Then, pour in 250 g of composite cooling powder and disperse at high speed for 30 minutes. Next, add 400 g of waterborne polyurethane resin, 10 g of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, 90 g of pigment powder and 2 g of defoamer (TEGOFoamex 810) in sequence and continue stirring and dispersing for 20 minutes to obtain waterborne polyurethane cooling slurry.

[0055] The composite cooling powder includes 75 g CuFe2O4, 50 g La2O3, 50 g Yb2O3, 50 g Al2O3 and 25 g Cr2O3.

[0056] The pigment powder includes: 70 g Fe3O4, 10 g MnO2 and 10 g MgO.

[0057] Add 20 g of aziridine to the waterborne polyurethane cooling slurry and stir for 10 minutes. Then filter the slurry through a 200-mesh screen and apply it to the coating. Control the appropriate wet film thickness to ensure that the coating thickness is 50 μm after drying and curing. Then bake at 120 ℃ for 8 minutes to further dry and cure the coating to form a cooling layer.

[0058] S2. Preparation of the reflective layer: First, weigh 100 g of deionized water, then add 8 g of leveling agent TEGO 410 and 25 g of sodium polyacrylate and stir for 2 minutes. Next, add 5 g of SiO2, 20 g of TiO2, 6 g of ZrO2, 15 g of BaSO4, 10 g of SiC, 8 g of Si3N4, 10 g of ZnSe, and 5 g of CaCO3, and disperse at high speed for 30 minutes. Then, add 500 g of waterborne polyurethane resin and 4 g of aziridine, and continue stirring and dispersing for 20 minutes to obtain a waterborne polyurethane reflective functional slurry. Finally, coat the waterborne polyurethane reflective functional slurry onto the cooling layer to a thickness of 80 μm, and then bake at 120℃ for 8 minutes to dry and cure, forming a reflective layer.

[0059] S3. Prepare the anti-aging layer: 100 g of waterborne polyurethane resin and 4 g of benzimidazole sulfonic acid were stirred and mixed, and then coated on the cooling layer with a coating thickness of 25 μm. The mixture was then baked at 120°C for 8 minutes to dry and cure, forming an anti-aging layer.

[0060] S4. Prepare the antifouling layer: Mix 100 g of waterborne polyurethane resin, 2 g of silica and 0.2 g of hydroxyl silicone oil, apply the mixture to the anti-aging layer with a thickness of 10 μm, and then bake at 120°C for 8 minutes to dry and cure to form an anti-fouling layer.

[0061] S5. Preparation of leather base fabric: At least one of woven fabric, knitted fabric, nonwoven fabric, and composite fabric is coated onto the reflective layer to a thickness of 165 μm. The final product is an electrically cooled leather prepared by layering an anti-fouling layer, an anti-aging layer, a cooling layer, a reflective layer, and a leather base fabric.

[0062] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that no composite cooling powder was added to the cooling layer in this comparative example.

[0063] The performance test data of the non-electric cooling leather prepared in Examples 1, 2 and Comparative Example 1 are shown in Table 1.

[0064] Table 1: As can be seen from Comparative Example 1, the lack of composite cooling powder in the leather prepared in this example resulted in a significant decrease in infrared emissivity, from 93% to 68%, and a substantial reduction in solar reflectivity. This is because the Al2O3 and Cr2O3 components in the composite cooling powder work synergistically with the reflective layer to reflect sunlight; the absence of the composite cooling powder also reduces solar reflectivity to a certain extent. Ultimately, this leads to a significant increase in the surface temperature of the leather.

[0065] Artificially accelerated aging resistance maintains good performance, exceeding 500 hours, as the anti-aging layer remains unchanged. The cooling layer utilizes a silane coupling agent to enhance material properties, working in conjunction with the anti-fouling and anti-aging layers to extend the leather's lifespan and achieve abrasion resistance and colorfastness rating of 5.

[0066] Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is that the non-electrically cooled leather prepared in this comparative example does not use pigment powder or uses conventional pigment powder. The performance test data of the non-electrically cooled leather are shown in Table 2.

[0067] Comparative Example 2-1: Based on Example 1, the black pigment powder component was removed.

[0068] Comparative Example 2-2: Formula for a conventional black pigment powder: 100g carbon black.

[0069] The performance test data of the non-electrically cooled leathers prepared in Comparative Examples 2-1 and 2-2 are shown in Table 2.

[0070] Table 2 From the data above, we can see that the black pigment powder used in Example 1 can effectively reduce the surface temperature of leather. The cooling effect is similar to that of the white leather with good natural reflectivity and low heat absorption in Comparative Example 2-1, indicating that the black leather prepared using the formula of this invention has excellent reflectivity and heat resistance.

[0071] The leather prepared using the black pigment powder in Embodiment 1 of this invention has a surface temperature that is 35°C lower than that prepared using traditional black pigment powder. This is because the pigment powder of this application, while providing melanin, can also work with the reflective layer to provide a certain solar reflectance, thereby reducing the absorption of sunlight by melanin. In contrast, using traditional black pigment powder would greatly increase the absorption rate of sunlight, thereby reducing the reflectance of sunlight and significantly increasing the surface temperature of the leather.

[0072] Comparative Example 3 The only difference between Comparative Example 3 and Example 1 is that no reflective layer was added to the non-electrically cooled leather prepared in this comparative example.

[0073] Comparative Example 4 The only difference between Comparative Example 4 and Example 1 is that the reflective layer was prepared using high-refractive-index particles alone and low-refractive-index particles alone.

[0074] Comparative Example 4-1 The only difference between Comparative Example 4-1 and Example 1 is that only high refractive index particles (refractive index > 2) are used in the reflective layer of Comparative Example 4-1: 30 g TiO2, 15 g ZrO2, 14 g SiC, 10 g Si3N4 and 10 g ZnSe.

[0075] Comparative Example 4-2 The only difference between Comparative Example 4-2 and Example 1 is that in Comparative Example 4-2, only low refractive index particles (refractive index < 1.6) were used in the reflective layer: 30 g SiO2, 34 g BaSO4 and 15 g CaCO3.

[0076] Comparative Example 5 The only difference between this comparative example and Example 1 is that the non-electrically cooled leather prepared in this comparative example did not have an anti-aging layer added.

[0077] The performance tests of the non-electrically cooled leathers prepared in Comparative Examples 3, 4-1, 4-2, and 5 are shown in Table 3.

[0078] Table 3 As shown in Comparative Example 3, the absence of a reflective layer significantly reduces the reflectivity of sunlight, thereby increasing the surface temperature of the leather. In Comparative Example 4-1, the addition of only high-refractive-index particles (refractive index > 2) produces a good reflectivity of sunlight, achieving a reflectivity of 50%. However, the reflectivity is slightly lower than the 55% of the leather prepared by combining high and low-refractive-index particles in Example 1. This is because the combination of high and low-refractive-index particles fills the spaces between high-refractive-index particles with low-refractive-index particles, increasing the refraction path of sunlight, increasing the scattering of sunlight, and slowing down the refraction intensity of sunlight, thereby reducing the absorption of the leather and increasing the probability of it being reflected back to the outside.

[0079] High-refractive-index particles refract sunlight more strongly, increasing the intensity of sunlight refraction to other layers and thus enhancing the leather's absorption of sunlight. Low-refractive-index particles, on the other hand, reflect sunlight less strongly, reducing the reflectivity of sunlight.

[0080] In Comparative Example 5, no anti-aging layer was added, but the sunlight reflectance and emissivity of the leather decreased. This is because the removal of the anti-aging layer made the leather unable to defend against ultraviolet light in the sun, thus shortening the service life of the leather. In the artificial accelerated aging test, the service life was only 100 hours, which is far less than the more than 500 hours that the leather in Example 1 could withstand in the artificial accelerated aging test.

[0081] Example 3 The only difference between this embodiment and Embodiment 1 is that the thickness of each layer in the non-electrically cooled leather prepared in this comparative example is different. The thickness data of each layer is shown in Table 4, and the effect data of different thicknesses are shown in Table 5.

[0082] Table 4 Table 5 The non-electric cooling leather prepared by this invention improves the leather's anti-aging properties, solar reflectance and infrared radiation performance by combining multiple layers of materials, reduces heat absorption on the leather surface, extends the leather's service life, and improves abrasion resistance and color fastness.

[0083] The thickness experiments show that as the thickness of the cooling and reflective layers increases, the infrared emissivity and solar reflectance improve. This is because it reduces the penetration of infrared and sunlight, thus increasing the efficiency of infrared radiation and solar reflection. However, at the same time, the thickness of the corresponding anti-aging and anti-fouling layers also needs to be increased to enhance UV protection, extend lifespan, and ultimately improve leather performance.

[0084] In the above experiments, when the thicknesses of the cooling layer and the reflective layer in Examples 3-4 reached 200μm and 140μm respectively, their thicknesses were greater than the 100μm thickness of the cooling layer and the 100μm thickness of the reflective layer in Example 1. However, the thicknesses of the anti-aging layer and the anti-fouling layer were slightly lower than those in Example 1. Although the accelerated aging test showed that when the thicknesses of the anti-aging layer and the anti-fouling layer were greater than 10μm and 6μm respectively, their accelerated service life was greater than 500h, the infrared emissivity, solar reflectance, and the reduction effect on the surface temperature of the leather were all lower than those in Example 1. Therefore, a certain thickness of anti-aging layer and anti-fouling layer is needed to work in conjunction with the cooling layer and the reflective layer to ensure the stability of their performance.

[0085] Example 4 The only difference between this embodiment and Embodiment 1 is that the mass of each component in the composite cooling powder used is different, as shown in Table 6, and the data of the prepared leather effect is shown in Table 7.

[0086] Table 6 Table 7 From the experimental results of Example 4, we can see that as the CuFe2O4 content decreases, the infrared emissivity and solar reflectance also gradually decrease. This is because CuFe2O4 has a high infrared emissivity, so a decrease in its content leads to a decrease in infrared emissivity. When the content is 0, the infrared emissivity drops to 60%. In addition, CuFe2O4 also contributes to some solar reflectance, affecting the solar reflectance of the leather. La2O3 also has a certain impact on the infrared emissivity of the leather; when the content decreases from 50g to 30g, the infrared emissivity decreases by about 6%.

[0087] Example 5 The only difference between this embodiment and Embodiment 1 is that the mass of each component in the pigment powder used in this embodiment is different, as shown in Table 8, and the leather effect data is shown in Table 9.

[0088] Table 8 Table 9 The experimental results of Example 5 show that, as the main color-adjusting raw material in the pigment powder, Fe3O4 gradually changes color from black to light gray as its content decreases. Secondly, a higher Fe3O4 content also reduces the reflectance of sunlight. Therefore, to balance the sunlight reflectance performance of the pigment powder, the contents of MnO2 and MgO must be appropriately matched to achieve both a suitable color and a certain increase in reflectance.

[0089] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A type of non-electrically cooled leather, characterized in that, It consists of an anti-fouling layer, an anti-aging layer, a cooling layer, a reflective layer, and a leather base fabric layer stacked together; The cooling layer comprises, by weight, 350-500 parts of waterborne polyurethane resin, 15-25 parts of crosslinking agent, 200-300 parts of composite cooling powder, 3-6 parts of leveling agent, 15-25 parts of dispersant, 8-12 parts of silane coupling agent, 1-3 parts of defoamer, 45-100 parts of pigment powder, and 80-120 parts of deionized water.

2. The non-electrically cooled leather as described in claim 1, characterized in that, The composite cooling powder comprises, by mass parts, 60-80 parts CuFe2O4, 40-60 parts La2O3, 40-60 parts Yb2O3, 40-60 parts Al2O3 and 20-30 parts Cr2O3.

3. The non-electrically cooled leather as described in any one of claims 1 or 2, characterized in that, The pigment powder comprises 35-70 parts Fe3O4, 10-20 parts MnO2, and 3-8 parts MgO by mass.

4. The non-electrically cooled leather as described in claim 3, characterized in that, The reflective layer comprises, by mass parts: 80-120 parts deionized water, 5-10 parts leveling agent, 20-30 parts dispersant, 400-600 parts waterborne polyurethane resin, 3-6 parts crosslinking agent, and 60-110 parts refractive particles.

5. The non-electrically cooled leather as described in claim 4, characterized in that, By mass fraction, the refracting particles include high refractive index particles with a refractive index > 2 and low refractive index particles with a refractive index < 1.6; The high refractive index particles include: 20-30 parts TiO2, 5-10 parts ZrO2, 8-10 parts SiC, 6-8 parts Si3N4, and 8-10 parts ZnSe; The low refractive index particles include: 10-20 parts of BaSO4, 3-8 parts of SiO2, and 3-8 parts of CaCO3.

6. The non-electrically cooled leather as described in claim 5, characterized in that, The anti-aging layer comprises, by weight, 80-120 parts of waterborne polyurethane resin and 1-5 parts of ultraviolet blocking agent.

7. The non-electrically cooled leather as described in claim 6, characterized in that, The antifouling layer comprises, by weight, 80-120 parts of waterborne polyurethane resin, 1-5 parts of silica, and 0.1-0.5 parts of antifouling additive.

8. The non-electrically cooled leather as described in claim 7, characterized in that, The thickness of the anti-fouling layer is 10~15μm, the thickness of the anti-aging layer is 25~30μm, the thickness of the cooling layer is 50~300μm, and the thickness of the reflective layer is 80~100μm.

9. A process for preparing electrically cooled leather, characterized in that, Using the non-electrostatic leather material as described in any one of claims 7-8, the preparation process includes: S1. Preparation of the cooling layer: First, the leveling agent and the dispersant are mixed evenly. Then, the composite cooling powder is added and stirred to disperse it. Next, the waterborne polyurethane resin, the silane coupling agent, the pigment powder, and the defoamer are added and stirred evenly to obtain the waterborne polyurethane cooling slurry. After crosslinking with the crosslinking agent, the water-based polyurethane cooling slurry is coated to prepare a cooling layer. S2. Preparation of the reflective layer: First, the leveling agent and the dispersant are stirred and mixed, then the refractive particles are added and stirred and dispersed, and then the waterborne polyurethane resin and the crosslinking agent are added and mixed to obtain a waterborne polyurethane resin reflective slurry; The reflective layer is obtained by coating the water-based polyurethane resin reflective slurry onto the cooling layer. S3. Prepare the anti-aging layer: The waterborne polyurethane resin and the ultraviolet blocker are mixed and then coated onto the cooling layer to obtain the anti-aging layer. S4. Preparation of antifouling layer: Waterborne polyurethane, the silica and the antifouling additive are mixed and then coated on the anti-aging layer to obtain the antifouling layer; S5. Preparation of the leather base fabric layer: The leather base layer is obtained by coating the reflective layer with at least one of woven fabric, knitted fabric, nonwoven fabric and composite fabric, thereby obtaining the complete electrically refrigerated leather.

Images