Wave-absorbing synthetic leather, preparation method and application thereof

Abstract

The application belongs to the technical field of synthetic leather, and particularly relates to a wave-absorbing synthetic leather as well as a preparation method and application thereof. The wave-absorbing synthetic leather is prepared by attaching a resin and wave-absorbing particle mixed slurry on a substrate; the wave-absorbing particle is a biomass-based porous carbon wave-absorbing agent or a biomass-based porous carbon and metal oxide composite wave-absorbing agent. The wave-absorbing synthetic leather is prepared by uniformly mixing a fabric resin, a wave-absorbing agent and wood powder, defoaming to obtain a slurry, attaching the slurry to a release paper, and then attaching the release paper to a substrate, drying and cooling, and then peeling off the release paper. The synthetic leather product prepared by the application not only has a smooth surface and good toughness of traditional leather, but also has good wave-absorbing effect. The method of the application has simple process, mild preparation conditions, is easy to operate, and the raw material source is cyclic and renewable, and the cost is low, which provides great potential for solving the problem of electromagnetic radiation or radiation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of synthetic leather, and particularly relates to a wave-absorbing synthetic leather and a preparation method and application thereof. BACKGROUND

[0002] The existing wave-absorbing synthetic leather process mainly selects graphene and carbon nanotubes and other commonly used high-performance functional fillers as carbon-based materials. The metal particles in the carbon-based composite material mainly select copper, silver, iron oxide, nickel, zinc and other nano metal powders as fillers. The preparation also includes the preparation of polyurethane, resin and the like, such as the preparation of a water-based polyurethane system and the preparation of other resins, and the doping of additives such as dispersants, surfactants, catalysts and defoamers in the slurry. Finally, after being mixed uniformly, the synthetic leather is obtained by being attached to the base through spraying, blade coating and dry lamination.

[0003] The raw material cost of the prior art is high, and the functional fillers (such as graphene, carbon nanotubes, nano silver, etc.) are expensive, which is one of the main factors leading to the increase in product cost. In addition, the additives (such as high-quality dispersants, catalysts, etc.) also increase the raw material procurement cost. In the cost-sensitive market field (such as the large-scale consumer product market), the high raw material cost limits the wide application of functional synthetic leather.

[0004] Secondly, in the prior art, the preparation process of the wave-absorbing functional leather involves multi-step reactions and complex operation procedures, whether it is the pre-treatment of carbon-based functional particles or the preparation of polyurethane.

[0005] Therefore, it is of great significance to develop a new wave-absorbing synthetic leather and a preparation method thereof. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a wave-absorbing synthetic leather using bio-based (coconut shell, peanut shell, loofah, corn cob, etc.) carbon materials as wave-absorbing particles, which has the characteristics of low cost, renewability, high specific surface area and porosity, and can be used as a substitute for carbon nanotube materials and graphene materials, in view of the deficiencies of the prior art.

[0007] Another problem to be solved by the present application is to provide a preparation method of the above-mentioned wave-absorbing synthetic leather, which uses resin and wave-absorbing particles to prepare a mixed slurry through a simple and mild method, without the need for high-temperature operation, the addition of other additives, and the need for too many complex process procedures, and finally the synthetic leather with wave-absorbing performance is obtained by simply attaching the base.

[0008] In order to solve the above technical problems, the present application discloses a wave-absorbing synthetic leather, which is prepared by attaching a resin and a wave-absorbing particle mixed slurry to a base material.

[0009] The microwave absorbing particles are biomass-based porous carbon microwave absorbers or biomass-based porous carbon and metal oxide composite microwave absorbers.

[0010] Specifically, the biomass-based carbon microwave absorber is sourced from one or more of coconut shells, peanut shells, loofah sponges, and corn cobs;

[0011] Preferably, the preparation method of the biomass-based porous carbon microwave absorber is as follows: the biomass material is ground into powder, mixed evenly with alkali, dried, then ground again, and then carbonized, washed, dried and ground again to obtain the biomass-based porous carbon microwave absorber.

[0012] More preferably, the preparation method of the biomass-based porous carbon and metal oxide composite microwave absorber is as follows: the above-mentioned biomass-based porous carbon microwave absorber is mixed evenly with FeCl3·6H2O, and polyethylene glycol and urea are added. After thorough mixing, the biomass-based porous carbon and metal oxide composite microwave absorber is prepared by solvothermal method.

[0013] The present invention also discloses a method for preparing the above-mentioned microwave-absorbing synthetic leather. The specific steps are as follows: the fabric resin, microwave-absorbing agent and wood powder are mixed evenly and defoamed to obtain a slurry. The slurry is poured onto release paper and then bonded to the substrate. After drying and cooling, it is peeled off from the release paper to obtain the microwave-absorbing synthetic leather.

[0014] Specifically, the amount of the microwave absorber added is 1-10% of the total mass of the fabric resin; the amount of the wood powder added is 3-15% of the total mass of the fabric resin.

[0015] Preferably, the amount of the microwave absorber added is 3% of the total mass of the fabric resin; and the amount of the wood powder added is 7% of the total mass of the fabric resin.

[0016] Specifically, the fabric resin comprises, by weight parts: 80-100 parts of HL-48 resin, 60-80 parts of DMF, 10-30 parts of methyl methacrylate, 10-18 parts of colorant 142, 0.2-0.5 parts of colorant 3809, 0.02-0.05 parts of colorant 3687, and 0.01-0.02 parts of colorant 2698;

[0017] Preferably, the fabric resin comprises, by weight parts: 90 parts HL-48 resin, 70 parts DMF, 20 parts methyl ester, 14 parts colorant 142, 0.32 parts colorant 3809, 0.045 parts colorant 3687, and 0.015 parts colorant 2698.

[0018] Specifically, the defoaming is vacuum defoaming. The specific steps are to defoam in a vacuum oven at room temperature and with a pressure of 100 Pa. The changes in bubbles are observed, and the whole process lasts for 5 to 30 minutes until no more bubbles are visible to the naked eye in the slurry. Finally, the pressure is returned to the same level as the external air pressure and the slurry is taken out.

[0019] Specifically, the drying conditions are: drying at 50~90℃.

[0020] This invention also protects the application of the aforementioned microwave-absorbing synthetic leather in the field of microwave absorption;

[0021] Preferably, the present invention protects the application of the microwave-absorbing synthetic leather in the field of Ku-band microwave absorption.

[0022] Specifically, in some embodiments of the present invention, microwave-absorbing synthetic leather was prepared by the above-described preparation method. By conducting microwave absorption tests in the Ku band and X band respectively, the best reflection loss RLmin of the microwave-absorbing synthetic leather was -55.4dB in the Ku band, while the reflection loss RLmin in the X band also exceeded -20dB, demonstrating the application prospects of the microwave-absorbing synthetic leather prepared by the present invention in the field of microwave absorption in the Ku band and X band. Beneficial effects

[0023] 1. Traditional synthetic leather typically lacks wave absorption capabilities, while the wave-absorbing synthetic leather of this invention achieves specific wave absorption properties. In areas with a high concentration of electronic equipment, it can reduce electromagnetic wave reflection and scattering, thereby lowering electromagnetic interference.

[0024] 2. The synthetic leather product obtained by this invention not only has the smooth surface and good toughness of traditional leather, but also has a good wave absorption effect.

[0025] 3. The method of the present invention is simple, the preparation conditions are mild, and it is easy to operate. The direct addition of functional particles to the resin reduces the complexity of the processing steps, while the resin also acts as a binder for the particles.

[0026] 4. The raw materials for this invention are recycled and renewable, and biomass-based carbon microwave absorbers are widely available and inexpensive. Combined with a simple, low-cost, lightweight, and scalable manufacturing method, biomass-derived hierarchical porous carbon is lightweight, durable, and has high microwave absorption performance, offering great potential for solving electromagnetic radiation or radiation problems, while also conforming to the current green development concept. Attached Figure Description

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0028] Figure 1This is a flowchart illustrating the preparation process of the microwave-absorbing synthetic leather of this invention;

[0029] Figure 2 This is a SEM image of the composite microwave absorbing agent 1 in Embodiment 1 of the present invention;

[0030] Figure 3 This is a SEM image of the microwave absorbing agent 2 in Embodiment 1 of the present invention;

[0031] Figure 4 The image shows the finished synthetic leather product 1 prepared in Example 2 of this invention;

[0032] Figure 5 The X-band absorption curves of the two types of microwave-absorbing synthetic leather in Embodiment 3 of the present invention are shown from left to right as finished synthetic leather of biomass 1 and finished synthetic leather of biomass 2.

[0033] Figure 6 The absorption curve of the biomass 1 finished synthetic leather in Example 3 of this invention in the Ku band;

[0034] Figure 7 The image shows the absorption curve of the biomass 2 finished synthetic leather in the Ku band in Example 3 of this invention. Detailed Implementation

[0035] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; unless otherwise specified, the reagents and materials are commercially available.

[0036] The raw materials in the following examples were procured as follows: Resin HL-48 was purchased from Fujian Chengjie Polymer Materials Co., Ltd., item number HL-48; Dimethylformamide (DMF) was purchased from Fujian Chengjie Polymer Materials Co., Ltd.; Fatty acid methyl ester (hereinafter referred to as methyl ester) was purchased from Pucheng Bomai Trading Co., Ltd.; Color powder 142 and color powder 2698 were purchased from Fujian Huapu Chemical Co., Ltd.; Color powder 3809 was purchased from Zhejiang Dali Industrial Co., Ltd.; Color powder 3687 was purchased from Fujian Dongli Chemical Industry Co., Ltd.; and Wood powder was purchased from Xiayi County Zhanyuan Wood Products Co., Ltd.

[0037] Example 1: Preparation of microwave absorbing agent

[0038] Preparation of Composite Microwave Absorber 1: First, the biomass material was alkali-activated. The biomass material used for Composite Microwave Absorber 1 was corn cob, and the alkali was KOH, with a mass ratio of corn cob to alkali of 2:1. The corn cob was ground into powder using a grinder, and 1g of the corn cob powder was set aside. An alkali solution of the corresponding concentration was prepared according to 100ml of KOH solution with a concentration of 5g / L. The corn cob powder and the alkali solution were mixed evenly under stirring. Then, the mixed solution was placed in an oven at 80℃ for drying. After drying, the material was cooled to room temperature and then ground until powder was obtained. The powder was placed in a tube furnace for carbonization, with the carbonization temperature set at 700℃ and the holding time at 3 hours. After carbonization, the carbonization product was repeatedly washed with water and dilute hydrochloric acid until the pH value reached neutral and excess salt was removed. Finally, the washed product was placed in an oven at 80℃ for drying and ground until there were no obvious large particles, thus obtaining porous corn cob carbon powder.

[0039] Next, spherical Fe3O4 / C composite microwave absorbing materials were prepared using a solvothermal method. First, 0.3 g of the prepared porous corn cob carbon powder was weighed and added to 50 mL of ethylene glycol, and then ultrasonically dispersed to ensure thorough and uniform dispersion. Then, 5 mmol of FeCl3·6H2O, 10 g of polyethylene glycol, and 1 g of urea were added to the uniformly dispersed solution. The mixture was mechanically stirred for 3 hours to ensure thorough mixing. Next, the resulting mixture was transferred to a polytetrafluoroethylene-lined container and reacted at 200 °C for 24 hours. After the reaction, the product was washed and filtered multiple times, and finally dried under vacuum for 12 hours to obtain the spherical Fe3O4 / C composite microwave absorbing material, named Composite Microwave Absorber 1.

[0040] Preparation of Wave Absorber 2: Wave Absorber 2 uses coconut shell as the biomass material and KOH as the alkali, with a mass ratio of coconut shell to alkali of 2:1. The coconut shell is ground into powder using a grinder, and 1g of the powder is set aside. An alkali solution of the appropriate concentration is prepared using 100ml of KOH solution with a concentration of 5g / L. The coconut shell powder and alkali solution are mixed evenly under stirring. After thorough mixing, the mixture is dried in an 80℃ oven. After cooling to room temperature, it is ground again, and the ground powder is carbonized in a tube furnace. The carbonization temperature is 600℃, and the holding time is 2 hours. Finally, the carbonized porous carbon is washed several times with water and dilute hydrochloric acid until the pH is neutral and excess salt is removed. It is then dried in an 80℃ oven. Finally, the dried coconut shell porous carbon is ground until there are no obvious large particles, yielding coconut shell porous carbon powder, named Wave Absorber 2.

[0041] The microstructure of the prepared composite microwave absorber 1 and microwave absorber 2 was characterized using scanning electron microscopy (SEM). Figure 2The image shows a SEM image of composite absorber 1. As can be seen, spherical Fe3O4 / C composite absorber material was successfully prepared via solvothermal precipitation. The smooth and uniformly distributed Fe3O4 particles are clearly visible growing on the carbon framework. In the composite absorber material, Fe3O4 acts as a magnetic loss agent, while the porous carbon from biomass 1 mainly acts as a dielectric loss agent. The synergistic effect of porous carbon and magnetic metal particles improves impedance matching, effectively achieving a multi-polarization loss mechanism to attenuate and scatter electromagnetic waves, resulting in better electromagnetic wave absorption.

[0042] Figure 3 The image shows the SEM image of absorber 2. As can be seen from the image, the absorber carbon material prepared from coconut shell powder exhibits an interconnected honeycomb porous structure, similar to a honeycomb. This structure greatly improves the incident rate of electromagnetic waves and enables multiple reflections and scattering of electromagnetic waves within the material. At the same time, it also enhances interfacial polarization loss, which is beneficial for the attenuation of electromagnetic waves and promotes the absorption effect.

[0043] Example 2: Preparation of microwave-absorbing synthetic leather

[0044] Weigh the fabric resin raw material and 7% (by weight of fabric resin) of wood powder according to Table 1. Mix them evenly, then add 3% (by weight of fabric resin) of composite microwave absorber 1 and microwave absorber 2 respectively. Stir thoroughly with a glass rod at room temperature until uniform, then let stand. Since a large number of bubbles are generated during the stirring process, which will result in an uneven surface in the final product, the prepared slurry is subjected to vacuum defoaming treatment. The specific steps are as follows: use a vacuum oven for defoaming treatment at room temperature and pressure around 100 Pa or lower. Observe the changes in bubbles at any time. The bubbles gradually grow, and you can see the small bubbles getting bigger and the large bubbles bursting. The whole process lasts 5 to 30 minutes until you can see no more bubbles growing in the slurry. Finally, return the pressure to the same level as the external air pressure and take out the slurry.

[0045] After the prepared slurry is vacuum defoamed until the surface is smooth and free of small bubbles, it is poured onto release paper. At the same time, a base material of about 3×5cm is cut and attached to the release paper. The mixture is then placed in an 80℃ oven to dry. After cooling, the release paper is peeled off from the finished leather to obtain biomass 1 finished synthetic leather and biomass 2 finished synthetic leather, respectively. Figure 4 This is a diagram of synthetic leather made from biomass 1.

[0046] Table 1. Fabric Resin Raw Materials

[0047] Raw materials Mass fraction Mass (kg) Resin HL-48 90 38 DMF 70 30 Methyl ester 20 8 Color powder 142 14 5.91 Color powder 3809 0.32 0.135 Color powder 3687 0.045 0.019 Color powder 2698 0.015 0.006

[0048] Example 3: Performance Testing of Biomass 1 Finished Synthetic Leather and Biomass 2 Finished Synthetic Leather

[0049] The absorption tests of the biomass-based synthetic leather products 1 and 2 prepared in Example 2 were performed using a vector network analyzer in the X-band (8.2~12.4GHz) and Ku-band (12.4~18GHz), respectively. Figure 5 The X-band absorption curves of synthetic leather products from biomass 1 and biomass 2 are shown. Figure 6 The Ku-band absorption curve of the finished biomass synthetic leather. Figure 7 The absorption curve of biomass 2 finished synthetic leather in the Ku band.

[0050] As shown in the figure, in the Ku band test of biomass 1 finished synthetic leather, the best reflection loss RLmin is -55.4dB when the matching thickness is 1mm. Figure 6 In the 1.5mm~5.5mm range, the absorption capacity does not exceed -10dB; compared to the finished synthetic leather from biomass 1, the finished synthetic leather from biomass 2 has slightly worse absorption performance. In the Ku band, the best reflection loss reaches -29.75dB when the matching thickness is 1mm. Figure 7 In summary, in the Ku band, both biomass 1 and biomass 2 synthetic leather products showed good wave absorption at 1 mm, indicating that the materials in this invention have excellent wave absorption capabilities even at relatively thin thicknesses.

[0051] The X-band (8.2~12.4GHz) absorption test results for biomass 1 and biomass 2 synthetic leather showed that their best absorption effect in the X-band was around -20dB. Figure 5 The absorption capacity of the two bands is lower than that of the Ku band. Secondly, compared with the absorption capacity of the Ku band, the matching thickness with the best absorption capacity in this band is greater than 1 mm. Compared with the previous band, the matching thickness of this band is slightly thicker and the absorption capacity is slightly worse.

[0052] The main characteristics of microwave absorbing materials are "thin," "light," "wide," and "strong." Different fabrics may have different microwave absorption effects at different thicknesses. Based on the results of the above embodiments, the microwave absorption capability of leather in this invention is manifested in the Ku band, with the optimal reflection loss RLmin being -55.4dB, which conforms to the concept of "strong" microwave absorbing materials. In this frequency band, the microwave absorption effect of synthetic leather in this invention is mainly manifested at 1mm, which conforms to the concept of "thin" microwave absorbing materials.

[0053] The main improvements of the product or method of this invention are as follows:

[0054] 1. Possesses wave absorption capability

[0055] In today's world of ubiquitous electronic devices, electromagnetic interference and radiation have become significant issues. Traditional synthetic leather typically lacks wave-absorbing capabilities, making it difficult to meet the demands of increasingly complex electromagnetic environments. This invention presents a wave-absorbing synthetic leather that achieves wave-absorbing properties, significantly reducing electromagnetic interference. It shows promising potential for applications in children's strollers, medical equipment, and military instrument packaging materials.

[0056] 2. Simple process

[0057] Compared to traditional coating processes, this invention features a tightly integrated and highly efficient workflow. The resin layer is directly adhered to the substrate, simplifying the process compared to the complex multi-step coating, drying, pre-drying, and curing processes found in some existing methods. This reduces energy consumption and time costs, improving production efficiency. Furthermore, the simplified process may reduce the risk of product quality instability caused by complex processes. Secondly, the integration of the biomass-based composite carbon microwave absorber with the synthetic leather substrate is optimized, reducing unnecessary pretreatment and waiting time. In the coating drying stage, the unique formula significantly increases the drying speed. Processes that previously required lengthy baking or resting periods can now achieve the desired drying effect in a shorter time, effectively shortening the overall production cycle, saving significant time and costs, and substantially improving production efficiency.

[0058] 3. Low cost

[0059] From the perspective of raw material costs, biomass-based carbon microwave absorbers are widely available and inexpensive, extracted and prepared from various waste biomass resources. Compared to some expensive or specialized synthetic microwave absorbers, this significantly reduces raw material procurement costs. In the production and processing stage, due to its excellent processing performance, the equipment requirements are relatively low, eliminating the need for complex and expensive processing equipment and special technological conditions, thus reducing equipment investment and operating costs. Furthermore, the synthetic leather coated with this material exhibits stable performance and low maintenance costs during subsequent use. All these factors combined make biomass-based carbon microwave absorber-coated synthetic leather highly competitive in terms of price, which is of great significance both for reducing production costs for large-scale manufacturers and for consumers to obtain more cost-effective products.

[0060] 4. Quantifiable

[0061] The amount of resin derived from this product's own fabric provides a foundation for the large-scale production of microwave-absorbing finished leather. Secondly, the "one-step" raw material preparation time strongly supports mass production of microwave-absorbing finished leather. Finally, regarding raw materials, biomass-based carbon microwave-absorbing agent-coated synthetic leather offers excellent quantifiable production conditions. Its production process exhibits high stability and repeatability, allowing for precise control of the quality and performance parameters of each batch during large-scale production. It enables the rapid and stable production of large quantities of standard-compliant products based on market demand, laying a solid foundation for the product's commercialization and widespread application.

[0062] This invention provides a method for preparing and applying microwave-absorbing synthetic leather. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A microwave-absorbing synthetic leather, characterized in that, The microwave-absorbing synthetic leather is made by attaching a mixture of resin and microwave-absorbing particles onto a substrate. The amount of microwave absorbing particles added is 3% of the total mass of the resin; the microwave absorbing particles are a biomass-based porous carbon and metal oxide composite microwave absorbing agent, which is prepared by: grinding biomass material into powder, mixing it evenly with alkali, drying it, then grinding it again, carbonizing it, washing it, drying it again, and grinding it again to obtain the biomass-based porous carbon microwave absorbing agent; mixing the biomass-based porous carbon microwave absorbing agent with FeCl3·6H2O evenly, adding polyethylene glycol and urea, mixing it thoroughly, and then preparing the biomass-based porous carbon and metal oxide composite microwave absorbing agent by solvothermal method; The amount of the biomass-based porous carbon microwave absorber is 0.3g; the amount of FeCl3·6H2O is 5mmol. The biomass material is corn cob; the metal oxide is Fe3O4; and the thickness of the microwave-absorbing synthetic leather is 1 mm.

2. The method for preparing the microwave-absorbing synthetic leather according to claim 1, characterized in that, The specific steps are as follows: after mixing the fabric resin, microwave absorbing particles and wood powder evenly and defoaming to obtain a slurry, the slurry is poured onto the release paper and then bonded to the substrate. After drying and cooling, it is peeled off from the release paper to obtain the microwave absorbing synthetic leather.

3. The preparation method according to claim 2, characterized in that, The amount of microwave absorbing particles added is 3% of the total mass of the fabric resin; the amount of wood powder added is 7% of the total mass of the fabric resin.

4. The preparation method according to claim 2, characterized in that, The defoaming is vacuum defoaming. The specific steps are to defoam in a vacuum oven at room temperature and pressure of 100 Pa, observe the changes in bubbles, and continue the process for 5 to 30 minutes until no more bubbles are visible to the naked eye in the slurry. Finally, the pressure is returned to the same level as the external air pressure and the slurry is taken out.

5. The preparation method according to claim 2, characterized in that, The drying conditions are as follows: drying at 50~90℃.

6. The application of the microwave-absorbing synthetic leather according to claim 1 in the field of microwave absorption.

7. The application according to claim 6, characterized in that, Application of the microwave-absorbing synthetic leather in the Ku-band microwave absorption field.

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