Polyester fabric / polyvinyl chloride / hollow microsphere composite material and preparation method thereof

Abstract

This invention belongs to the field of composite material technology, specifically relating to a polyester fabric / polyvinyl chloride / hollow microsphere composite material and its preparation method. The invention discloses a polyester fabric / polyvinyl chloride / hollow microsphere composite material, comprising a polyester fabric base layer, a polyvinyl chloride layer, and hollow glass microspheres dispersed in the polyvinyl chloride layer. The hollow glass microspheres have a particle size of 50-70 μm, and their volume fraction in the polyvinyl chloride layer is 10%-30%. This invention also discloses a method for preparing this composite material, which exhibits excellent thermal insulation performance and promising market application prospects.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology, specifically relating to polyester fabric / polyvinyl chloride / hollow microsphere composite material and its preparation method. Background Technology

[0002] In recent years, global warming and the consumption of fossil fuels have received increasing attention, and thermal insulation materials are playing an increasingly important role. With the introduction of sustainable development strategies and the growing call for energy conservation and environmental protection, developing a thermally insulating automotive interior material is of significant practical importance. Therefore, improving the thermal insulation performance of polyester fabric / polyvinyl chloride composite materials is an urgent problem to be solved.

[0003] Hollow glass microspheres (HGM) are an attractive functional spherical filler for composite materials due to their isotropy, low density, good chemical stability, excellent moisture resistance, and thermal insulation properties. HGM is a micron-sized hollow glass sphere, an inorganic non-metallic material processed from borosilicate raw materials. It is a versatile and high-performance lightweight material. Its tiny spherical structure not only gives it excellent flowability—better dispersibility and flowability than sheet-like, needle-like, or irregularly shaped fillers, resulting in superior filling performance—but also endows it with isotropy. This characteristic allows it to effectively control shrinkage in all directions during the curing process when used as a filler in a matrix material, ensuring dimensional stability and preventing warping. The hollow structure of HGM also gives it low density and low thermal conductivity, making it an ideal filler for improving the thermal insulation performance of composite materials.

[0004] CN101418105B discloses a rigid polyvinyl chloride (PVC) material reinforced with hollow glass microspheres and its preparation method. The weight ratio of the components—PVC resin powder, hollow glass microspheres, coupling agent, heat stabilizer, lubricant, processing modifier, and impact modifier—is 100:1–50:0.1–10.0:0.5–3.0:0.2–5.0:0.1–5.0:0.1–10.0. This invention utilizes coupling compatibility and distribution technology to composite hollow glass microspheres with resin and directly injection mold them, resulting in a rigid PVC material reinforced with hollow glass microspheres that exhibits higher impact strength, water pressure and burst strength, and higher dimensional stability. However, there are currently no reports on using HGM to improve the thermal insulation performance of polyester fabric / PVC composites. Therefore, researching the application of HGM in improving polyester fabric / PVC composites is of great significance. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention explores the application of HGM in research to improve the thermal insulation performance of polyester fabric / PVC composite materials, and develops a novel thermal insulation composite material with good thermal insulation performance: polyester fabric / polyvinyl chloride / hollow microsphere composite material.

[0006] On one hand, the present invention discloses a polyester fabric / polyvinyl chloride / hollow microsphere composite material, the composite material comprising a polyester fabric base layer, a polyvinyl chloride layer and hollow glass microspheres dispersed in the polyvinyl chloride layer, wherein the particle size of the hollow glass microspheres is 50μm-70μm and the volume fraction of the hollow glass microspheres in the polyvinyl chloride layer is 10%-30%.

[0007] Furthermore, the hollow glass microspheres in the composite material are dispersed in the polyvinyl chloride layer in the form of a particle size gradient distribution and / or a volume fraction gradient distribution.

[0008] On the other hand, the present invention also discloses a method for preparing the composite material, the method comprising the following steps:

[0009] Step 1: Prepare a polyvinyl chloride-hollow microsphere mixture paste;

[0010] Step 2: Apply the polyvinyl chloride-hollow microsphere mixture paste prepared in Step 1 onto the polyester fabric using a hand lay-up process and spread it evenly.

[0011] Step 3: Place the polyester fabric coated with the mixed paste obtained in Step 2 into a drying device and heat it to cure.

[0012] Step 4: Cut and polish the composite material cured in Step 3 to obtain polyester fabric / polyvinyl chloride-hollow microsphere composite material.

[0013] Furthermore, the method for preparing the polyvinyl chloride-hollow microsphere mixed paste includes the following steps:

[0014] S1, Preparation of polyvinyl chloride resin mixture: Polyvinyl chloride paste resin EPVC, tributyl citrate TBC and epoxidized soybean oil ESO are mixed and stirred at the first speed for 30 minutes to prepare a uniform polyvinyl chloride resin paste mixture.

[0015] S2, weigh a certain amount of hollow glass microspheres HGM, add them to the well-stirred polyvinyl chloride resin paste mixture, and stir at a second speed less than the first speed for 60 minutes to obtain a polyvinyl chloride-hollow microsphere mixture paste.

[0016] Furthermore, in the method, the volume fraction of hollow glass microspheres (HGM) in step S2 is 10%-30%.

[0017] Furthermore, in the method, the volume fraction of hollow glass microspheres (HGM) in step S2 is 30%.

[0018] Furthermore, in the method, the particle size of the hollow glass microspheres (HGM) in step S2 is 50 μm-70 μm.

[0019] Furthermore, in the method, the particle size of the hollow glass microspheres (HGM) in step S2 is 70 μm.

[0020] Furthermore, in the method, the particle size of the hollow glass microspheres (HGM) in step S2 is a gradient particle size, wherein the gradient particle sizes are 50μm-70μm / 60μm / 50μm-70μm respectively.

[0021] Furthermore, in the method, the volume fraction of hollow glass microspheres (HGM) in step S2 is a gradient volume fraction, which is 10%-30% / 20% / 10%-30%.

[0022] Furthermore, in the method, the mass ratio of polyvinyl chloride paste resin (EPVC), tributyl citrate (TBC), and epoxidized soybean oil (ESO) in S1 is 100:130:7.

[0023] Compared with the prior art, the present invention has at least the following advantages or beneficial effects:

[0024] This invention applies HGM to the study of improving the thermal insulation performance of polyester fabric / PVC composite materials, developing a novel thermal insulation composite material with good thermal insulation properties. The preparation process of this novel composite material is disclosed, revealing that the hand lay-up molding process, which distributes hollow microspheres in a gradient distribution within the composite material, can significantly improve its thermal insulation performance. The measured results are as follows: Figure 13 The study showed that the thermal insulation performance was optimal when the volume fraction of HGM microspheres in insulating glass was 30% / 20% / 10%. Attached Figure Description

[0025] Figure 1 The images show the morphology of HGM particles of different sizes in this application.

[0026] Figure 2 This is a process flow diagram for this application.

[0027] Figure 3 This is a diagram showing the effect of HGM volume fraction on the bulk density of the composite material in this application.

[0028] Figure 4 The following figures show the effect of HGM volume fraction on the thermal insulation performance of the composite material in this application: (a) thermal conductivity; (b) thermal diffusivity.

[0029] Figure 5Infrared images of composite materials containing different volume fractions of HGM as described in this application.

[0030] Figure 6 The following are curves showing the surface temperature of composite materials containing different volume fractions of HGM as a function of time: (a) curve; (b) magnified view.

[0031] Figure 7 The figure shows the effect of HGM particle size on the bulk density of the composite material in this application.

[0032] Figure 8 The effect of HGM particle size on the thermal insulation performance of composite materials in this application is shown in (a) thermal conductivity and (b) thermal diffusivity.

[0033] Figure 9 The following are curves showing the surface temperature of the composite material containing HGM of different particle sizes as a function of time: (a) curve; (b) enlarged view.

[0034] Figure 10 The results show the test results of the effect of HGM particle size gradient distribution on the thermal insulation performance of the composite material.

[0035] Figure 11 SEM images of composite materials with different HGM particle size gradient distributions in this application: (a) Fabric / 60 / 60 / 60; (b) Fabric / 50 / 60 / 70; (c) Fabric / 70 / 60 / 50.

[0036] Figure 12 The diagram shows the thermal conduction of the composite material in this application; (a) Fabric / 60 / 60 / 60; (b) Fabric / 50 / 60 / 70; (c) Fabric / 70 / 60 / 50.

[0037] Figure 13 The effect of HGM volume fraction gradient distribution on the thermal insulation performance of the composite material in this application; (a) thermal conductivity and thermal diffusivity; (b) surface temperature change over time.

[0038] Figure 14 SEM images of composite materials with different HGM volume fraction gradient distributions in this application: (a) Fabric / 30% 20% / 10%; (b) Fabric / 10% 20% / 30%; (c) Fabric / 20% 20% / 20%. Detailed Implementation

[0039] The technical solution of the present invention will be described below with reference to the embodiments. However, the present invention is not limited to the following embodiments.

[0040] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings. However, the embodiments described are not intended to limit the present invention.

[0041] Unless otherwise specified, the experimental and detection methods described in the following embodiments are conventional methods; unless otherwise specified, the reagents and materials are commercially available.

[0042] The insulating glass microspheres were purchased from 3M, model VS5500.

[0043] Example 1

[0044] This embodiment describes the sieving of HGM.

[0045] To prepare HGM with different particle sizes, HGM was sieved multiple times using standard sieves of different mesh sizes. The conversion between standard sieve mesh size and particle size was based on the Taylor standard sieve system. Using a 200-mesh sieve aperture size of 0.074 mm as a baseline, multiplying or dividing by the square root of the principal modulus 2 to the power of n (n = 1, 2, 3…) yields sieve aperture sizes coarser or finer than 200 mesh. Multiplying or dividing by the fourth root of the secondary modulus 2 (1.1892) to the power of n yields a series of sieve sizes with even finer graduations. The specifications of the sieves used in this embodiment are shown in Table 1. Since HGM is a hard, hollow, thin-walled, and lightweight sphere, the sieving process must be conducted in a closed environment to prevent the scattered HGM particles from being difficult to collect.

[0046] Table 1 Specifications of Standard Sampling Sieves

[0047] Number of meshes (mesh) 320 270 260 250 240 200 Aperture (μm) 48 53 57 63 65 75

[0048] Using the sieves in Table 1, a series of sieves were used to sieve the VS5500 HGM, and HGM with average particle sizes of 50μm, 60μm and 70μm were obtained.

[0049] The bulk density of HGM particles of different sizes was tested using a 3H-2000PS series fully automatic surface and pore size analyzer. Bulk density, i.e., the ratio of the mass of HGM to its true volume (the true volume of HGM refers to the volume of the HGM aggregate after removing the volume of the pores between the microspheres), was determined. An airtightness test was performed before the test. During the test, the sample tube and filling rod were first installed, and the volume of the empty tube (V1) was measured. Then, the sample tube was disassembled, and the sample of mass M was loaded into the sample tube. The filling rod was then also loaded into the sample tube, and the volume of the sample tube after loading (V2) was measured. After the test, the true density ρ of the sample was calculated using the formula.

[0050] ρ=M / (V1-V2)

[0051] Each sample was tested 5 times, and the average value was taken.

[0052] HGM separated by different types of standard sieves was observed using field emission scanning electron microscopy. The results are as follows: Figure 1 As shown. Figure 1 In Figures (a), (b), and (c), HGM particles with diameters of 70 μm, 60 μm, and 50 μm are shown, respectively. As can be seen from the figures, the HGM particles sieved using the standard sieve are relatively uniform in size, indicating that the standard sieve has a good sieving effect on HGM and can be used for subsequent composite material preparation.

[0053] To further analyze the effect of particle size difference on HGM bulk density, the bulk density was measured using a 3H-2000PS series fully automatic surface and pore size analyzer, and the results are shown in Table 2.

[0054] Table 2. Bulk density of HGM with different particle sizes

[0055] Particle size (μm) 50±2 60±2 70±5 <![CDATA[Apparent density (g / cm 3 )]]> 0.3821±0.0016 0.3811±0.0019 0.3798±0.0017

[0056] It is easy to see from Table 2 that the bulk density of HGM particles of different sizes is all around 0.38 g / cm³. 3 The particle size fluctuates left and right. Compared with the density of 0.38 for HGM (VS5500 type) raw material given by 3M, this shows that the difference in HGM particle size has a negligible effect on its bulk density.

[0057] Example 2

[0058] This example demonstrates the preparation of a polyester fabric / polyvinyl chloride-hollow microsphere composite material.

[0059] (1) Preparation of polyvinyl chloride-hollow microsphere mixed paste

[0060] Polyvinyl chloride paste resin (EPVC), tributyl citrate (TBC) and epoxidized soybean oil (ESO) were mixed in a mass ratio of 100:130:7 and stirred at 1000 r / min for 30 min to obtain a PVC resin paste mixture.

[0061] Weigh a certain amount of HGM (VS5500 type) and slowly add it to the uniformly stirred PVC resin paste mixture. Stir at 600 r / min for 60 min to prepare PVC-HGM mixed pastes with HGM volume fractions of 0%, 10%, 20%, and 30%. Weigh out HGM prepared in Example 1 with average particle sizes of 50 μm, 60 μm, and 70 μm according to an HGM volume fraction of 30%, and then slowly add it to the uniform PVC resin paste mixture. Stir at 600 r / min for 60 min to prepare PVC-HGM mixed pastes with average particle sizes of 50 μm, 60 μm, and 70 μm.

[0062] (2) Preparation of polyester fabric / polyvinyl chloride-hollow microsphere composite material

[0063] Polyester fabric was used as the reinforcing material. The prepared PVC-HGM mixed paste was coated onto the polyester fabric and spread evenly using a scraper.

[0064] Polyester fabric coated with the mixed paste was placed in a drying oven or similar drying equipment and cured at 80°C for 2 hours. The cured composite material was then cut and polished to obtain a polyester fabric / polyvinyl chloride-hollow microsphere composite material.

[0065] The process flow diagram of this embodiment is as follows: Figure 2 As shown.

[0066] Example 3

[0067] This embodiment is a process optimization experiment for polyester fabric / polyvinyl chloride-hollow microsphere composite materials.

[0068] 3.1 Test on the effect of different HGM volume fractions on the properties of polyester fabric / polyvinyl chloride-hollow microsphere composite material.

[0069] Using the method of Example 2, four polyester fabric / polyvinyl chloride-hollow microsphere composite materials with a thickness of 1.6 mm and HGM (model VS5500) volume contents of 0%, 10%, 20%, and 30% were prepared respectively. These were used for performance testing of the composite materials prepared under the HGM volume fraction conditions.

[0070] 3.1.1 Density test of composite materials

[0071] The bulk density of the composite material prepared above was tested using the water displacement method, and the results are as follows: Figure 3 As shown, the bulk density of the composite material decreases with increasing HGM content in the matrix material. The composite material with a HGM volume fraction of 30% in the matrix has a bulk density of 0.883 g / cm³. 3Compared to the composite material with a volume fraction of 0 HGM in the matrix, the bulk density is 1.135 g / cm³. 3 This represents a 22.2% reduction. This indicates that the composite material with a 30% HGM volume fraction has better thermal insulation performance.

[0072] 3.1.2 Thermal insulation performance test of composite materials

[0073] The thermal conductivity, thermal diffusivity, and other properties of the material were tested using a Hotdisk thermal constant analyzer at 20°C. The test results are as follows: Figure 4 As shown.

[0074] Depend on Figure 4 As shown in Figure (a), the thermal conductivity of the composite material gradually decreases with increasing HGM volume fraction. The thermal conductivity of the composite materials with HGM volume fractions of 0%, 10%, 20%, and 30% in the matrix are 0.2247 W / (m·K), 0.1974 W / (m·K), 0.1802 W / (m·K), and 0.1656 W / (m·K), respectively. The thermal conductivity of the composite material with an HGM volume fraction of 30% is 26.30% lower than that of the composite material without HGM in the matrix. The decrease in thermal conductivity of the composite material indicates an improvement in its thermal insulation performance.

[0075] Depend on Figure 4 As can be seen in Figure (b), the thermal diffusivity of the composite material gradually decreases with increasing HGM volume fraction. The thermal diffusivity of the composite materials with HGM volume fractions of 0%, 10%, 20%, and 30% in the matrix are 0.2227 mm. 2 / s, 0.1866mm 2 / s, 0.1694mm 2 / s, 0.1523mm 2 The thermal diffusivity of the composite material with a volume fraction of 30% HGM is reduced by 31.61% compared to the composite material without HGM in the matrix. The reduced thermal diffusivity of the composite material also indicates improved thermal insulation performance.

[0076] To further analyze the influence of HGM volume fraction on the thermal insulation performance of composite materials, an infrared thermal imager was used to capture the surface temperature field distribution of the composite materials.

[0077] Under ambient temperatures of 23℃ and relative humidity of 55%, the infrared thermal imager's camera was fixed 50cm directly above the heating stage. The composite material sample was quickly placed onto the 40℃ electric heating stage using tweezers. Timing began the instant the sample was placed on the stage, recording the change in surface temperature distribution T of the composite material over time t. Images were acquired every 6 seconds. The results of image acquisition under the infrared thermal imaging system for composite material samples with HGM volume fractions of 0%, 10%, 20%, and 30% are shown below. Figure 5 As shown.

[0078] from Figure 5 It can be seen that from the moment the composite material sample first came into contact with the electric heating stage to 6 seconds, the infrared images of the four composite material samples with HGM volume fractions of 0%, 10%, 20%, and 30% all changed rapidly, indicating that the surface temperature of the composite material sample rose rapidly. As the contact time increased, the changes in the infrared images of the composite material sample tended to slow down, indicating that the temperature change on the surface of the composite material sample gradually leveled out.

[0079] To more intuitively compare and analyze the impact of HGM volume fraction on the thermal insulation performance of composite materials, we will... Figure 5 The temperature data represented by the mid-infrared images are placed in the same coordinate system, and plotted as follows: Figure 6 The curve shown.

[0080] from Figure 6 As can be seen in (a), the temperature of the composite material sample surface rises rapidly within the first 6 seconds, and the temperature change of the composite material sample surface tends to be gradual after 30 seconds. Figure 6 Figure (b) is a magnified view of the surface temperature change of the composite material sample over time from 0 to 6 seconds. It clearly shows that the composite material sample with an HGM volume fraction of 0 has the steepest slope of the temperature-time curve, followed by the sample with an HGM volume fraction of 10%, then the sample with an HGM volume fraction of 20%, and the sample with an HGM volume fraction of 30% has the steepest slope. A steeper slope of the temperature-time curve indicates a faster temperature rise within the same time period, meaning a faster rate of heat conduction and consequently, poorer thermal insulation performance. This shows that the thermal insulation performance of the four composite material samples with HGM volume fractions of 0%, 10%, 20%, and 30% increases sequentially.

[0081] Test results of the bulk density and thermal insulation performance of composite materials prepared with different HGM volume fractions showed that the composite material with an HGM volume fraction of 30% had the best performance.

[0082] 3.2 Test on the effect of different HGM particle sizes on the properties of polyester fabric / polyvinyl chloride-hollow microsphere composites

[0083] To further analyze the influence of HGM particle size on the density of composite materials, composite materials with an HGM volume fraction of 30% were prepared using HGM with average particle sizes of 50 μm, 60 μm, and 70 μm obtained by sieving, and their properties were tested.

[0084] 3.2.1 Test results of the effect of HGM particle size on the bulk density of composite materials

[0085] Test results are as follows Figure 7 As shown, the bulk density of the composite material decreases slightly with the increase of HGM particle size, indicating that the porosity inside the composite material with larger HGM particle size is higher than that inside the composite material with smaller HGM particle size. That is, as the HGM particle size increases, the porosity inside the composite material also increases accordingly.

[0086] 3.2.2 Test results of the effect of HGM particle size on the thermal insulation performance of composite materials

[0087] The thermal insulation properties of the three prepared composite materials were tested using a Hotdisk thermal constant analyzer and an infrared thermal imager, respectively. The results are as follows: Figure 8 and Figure 9 As shown.

[0088] Depend on Figure 8 It is evident that the thermal conductivity and thermal diffusivity of the composite material decrease with increasing HGM particle size. The thermal conductivity of the composite material with 70 μm HGM particles is 0.1594 W / (m·K), which is 7.27% lower than the 0.1719 W / (m·K) of the composite material with 50 μm particles. The thermal diffusivity of the composite material with 70 μm HGM particles is 0.1487 mm. 2 / s, the thermal diffusivity of the composite material with a specific particle size of 50μm is 0.1664mm. 2 / s, a decrease of 10.64%. The decrease in thermal conductivity and thermal diffusivity of the composite material indicates an improvement in its thermal insulation performance.

[0089] Depend on Figure 9As shown in (a), when the composite material is placed on an electric heating platform with a set temperature of 40℃, the surface temperature rises rapidly in the first 6 seconds, then rises slowly between 6 and 30 seconds, and finally stabilizes after 30 seconds. The surface temperatures of the composite material samples with HGM particle sizes of 50μm, 60μm, and 70μm stabilize at 42.05℃, 41.30℃, and 40.81℃, respectively, at 54 seconds. If the initial temperature of the materials is the same, the greater the surface temperature change after being placed on a heating platform at the same temperature for the same amount of time, the worse the thermal insulation performance. The initial temperatures of the three groups of composite material samples with HGM particle sizes of 50μm, 60μm, and 70μm are basically the same. After being placed on an electric heating platform at the same temperature for a certain period of time, the stable surface temperature decreases sequentially, indicating that the surface temperature change decreases sequentially and the thermal insulation performance improves sequentially. At the same time, from Figure 9 As can be seen in Figure (b), within 0 to 6 s, the slopes of the temperature-time curves of the three groups of composite material samples with HGM particle sizes of 50 μm, 60 μm, and 70 μm are 1.90, 1.85, and 1.77, respectively. The slopes decrease sequentially, indicating that the temperature change of the three groups of composite material samples with HGM particle sizes of 50 μm, 60 μm, and 70 μm slows down sequentially within 6 s after they first come into contact with the 40℃ electric heating table. This result also shows that the thermal insulation performance of the composite material improves with the increase of HGM particle size.

[0090] In summary, the analysis of data such as the thermal conductivity, thermal diffusivity, surface temperature change of the composite material over time when placed on an electric heating table, and the slope of the temperature-time curve in the initial period fully demonstrates that the thermal insulation performance of the composite material improves with the increase of HGM particle size.

[0091] 3.3 Influence of HGM Particle Size Gradient Distribution on the Thermal Insulation Performance of Composite Materials: Test Experiment

[0092] To further investigate the influence of HGM particle size gradient distribution on the thermal insulation performance of composite materials, three HGM particle size gradient distributions were designed: 60 / 60 / 60, 50 / 60 / 70, and 70 / 60 / 50. Three composite materials with these distributions (Fabric / 60 / 60 / 60, Fabric / 50 / 60 / 70, and Fabric / 70 / 60 / 50) were prepared using the hand lay-up method. The thermal insulation performance of the composite materials was tested using a Hotdisk thermal constant analyzer and an infrared thermal imager. The results are shown below. Figure 10 As shown.

[0093] Figure 10Figure (a) shows the effect of HGM particle size gradient distribution on the thermal conductivity and thermal diffusivity of the composite material. Among the three groups of composite materials with different HGM particle size gradient distributions, the thermal conductivity and thermal diffusivity of the Fabric / 70 / 60 / 50 composite material are 0.1487 W / (m·K) and 0.1231 mm, respectively. 2 The values ​​of / s are the lowest among the three groups of composite materials with HGM particle size distribution, indicating that the composite material with an HGM particle size gradient distribution of 70 / 60 / 50 has the best thermal insulation performance. The thermal conductivity and thermal diffusivity of the two groups of composite materials with HGM particle size gradient distributions of 60 / 60 / 60 and 50 / 60 / 70 are not significantly different, indicating that the thermal insulation performance of composite materials Fabric / 60 / 60 / 60 and Fabric / 50 / 60 / 70 are similar. Among the three composite materials with HGM particle size gradient distributions, the composite material Fabric / 70 / 60 / 50, which has the best thermal insulation performance, has a 10.15% lower thermal conductivity and a 20.42% lower thermal diffusivity than the composite material Fabric / 50 / 60 / 70, which has the worst thermal insulation performance. This shows that the HGM particle size gradient distribution has a significant impact on the thermal insulation performance of composite materials.

[0094] Figure 10 Figure (b) shows the effect of HGM particle size distribution on the surface temperature versus time of the composite material. Figure 10 As can be seen in (b), the trend of material surface temperature change with time is basically the same in the three groups of composite materials with different HGM particle size gradient distributions. They all start from the moment the composite material comes into contact with the electric heating table, the material surface temperature rises at a relatively fast rate, and then the rate gradually slows down until it stabilizes at a certain temperature.

[0095] Among the three groups of composite materials with different HGM particle size distributions, the surface temperature of Fabric / 70 / 60 / 50 composite material changed the slowest over time, and the lowest temperature at which it tended to stabilize, indicating that it had the best thermal insulation performance. The surface temperature changes of Fabric / 50 / 60 / 70 and Fabric / 60 / 60 / 60 composite materials over time were basically the same, and the temperatures at which they tended to stabilize were also very close, indicating that the thermal insulation performance of Fabric / 50 / 60 / 70 and Fabric / 60 / 60 / 60 composite materials was basically the same, and the thermal insulation performance of neither of these composite materials was as good as that of Fabric / 70 / 60 / 50 composite material.

[0096] Three composite materials with different HGM particle size distributions have the same composition, thickness, and bulk density, but their thermal insulation performance varies significantly. This is mainly attributed to their different internal structures. Figure 11Images (a), (b), and (c) are microscopic photographs of the cross-sectional structures of three composite materials with HGM particle size distributions of Fabric / 60 / 60 / 60, Fabric / 50 / 60 / 70, and Fabric / 70 / 60 / 50, respectively. Figure 11 As can be seen, the three composite materials with different HGM particle size distributions prepared by hand lay-up have a clear gradient distribution in their cross sections.

[0097] The heat conduction of three composite materials with HGM particle size distributions of Fabric / 60 / 60 / 60, Fabric / 50 / 60 / 70, and Fabric / 70 / 60 / 50 can be achieved through… Figure 12 Perform the analysis. Figure 11 Figures (a), (b), and (c) show the thermal conduction of composite materials with HGM particle size distributions of Fabric / 60 / 60 / 60, Fabric / 50 / 60 / 70, and Fabric / 70 / 60 / 50, respectively. The temperature difference is greatest at the surface of the material in contact with the external environment, where the tendency for heat transfer is strongest. As heat transfers from the external environment into the material's interior, the temperature difference decreases, and the tendency for heat transfer weakens. Figure 12 The thermal insulation performance of the Fabric / 60 / 60 / 60 composite material remains unchanged as the heat transfer tendency decreases. Figure 12 In the middle (b) composite material Fabric / 50 / 60 / 70, the thermal insulation ability gradually weakens as the heat transfer trend decreases. Figure 12 In (c), the thermal insulation capacity of the composite material Fabric / 70 / 60 / 50 gradually increases as the heat transfer trend weakens, indicating that the composite material Fabric / 70 / 60 / 50 exhibits significantly better thermal insulation performance than the composite materials Fabric / 60 / 60 / 60 and Fabric / 50 / 60 / 70.

[0098] 3.4 Test on the effect of HGM volume fraction gradient distribution on the thermal insulation performance of composite materials

[0099] To investigate the effect of HGM volume fraction gradient distribution on the thermal insulation performance of composite materials, three HGM volume fraction gradient distributions were designed: 20% / 20% / 20%, 10% / 20% / 30%, and 30% / 20% / 10%. Composite materials with these gradients (Fabric / 20% / 20% / 20%, Fabric / 10% / 20% / 30%, and Fabric / 30% / 20% / 10%) were prepared using the hand lay-up method. The thermal insulation performance of the composite materials was tested using a Hotdisk thermal constant analyzer and an infrared thermal imager. The results are shown below. Figure 13 As shown.

[0100] Figure 13 (a) shows the effect of HGM volume fraction gradient distribution on the thermal conductivity and thermal diffusivity of the composite material. Among the three groups of composite materials with different HGM volume fraction gradient distributions, the composite material with an average volume fraction distribution of Fabric / 20% / 20% / 20% has a thermal conductivity of 0.1802 W / (m·K) and a thermal diffusivity of 0.1694 mm. 2 The thermal conductivity and thermal diffusivity of both composite materials with HGM volume fraction gradient distributions (Fabric / 10% / 20% / 30% and Fabric / 30% / 20% / 10%) showed a decreasing trend. Among them, the Fabric / 30% / 20% / 10% composite material showed a greater decrease, with thermal conductivity and thermal diffusivity decreasing by 12.04% and 20.60%, respectively. The test results of thermal conductivity and thermal diffusivity indicate that the HGM volume fraction gradient distribution significantly improves the thermal insulation performance of the composite material.

[0101] Figure 13 (b) shows the effect of HGM volume fraction distribution on the surface temperature versus time relationship of the composite material. Figure 13 (b) It can be seen that among the three groups of composite materials with different HGM volume fraction gradient distributions, the composite material with a volume fraction gradient distribution (Fabric / 30% / 20% / 10%) exhibits the slowest temperature change over time and the lowest temperature at which it tends to stabilize, indicating that it has the best thermal insulation performance. The composite material with a uniform volume fraction distribution (Fabric / 20% / 20% / 20%) shows the fastest temperature change over time and the highest temperature at which it tends to stabilize, indicating that it has the worst thermal insulation performance. The composite material with a volume fraction gradient distribution (Fabric / 30% / 20% / 10%) shows a moderate temperature change over time. Analysis of the relationship between the surface temperature of the composite material and time shows that an HGM volume fraction gradient distribution can improve the thermal insulation performance of the composite material, with the Fabric / 30% / 20% / 10% distribution showing the best thermal insulation performance.

[0102] The reason why the three groups of composite materials with different HGM volume fraction distributions have significant differences in thermal insulation performance when they have the same thickness and bulk density is that their internal structures are different. Figure 14 These are microscopic images of the cross-sectional structures of three composite materials with HGM volume fraction gradients of 20% / 20% / 20%, 10% / 20% / 30%, and 30% / 20% / 10%. Figure 14 (a) and

[0103] (b) are cross-sectional views of composite materials with HGM volume gradient distributions of Fabric / 30% / 20% / 10% and Fabric / 10% / 20% / 30%, respectively. It can be seen that in the portion with a 30% HGM volume fraction, due to the higher aggregation degree of the hollow glass microspheres, a certain amount of pores appear between the HGM particles. The cross-section of the Fabric / 20% / 20% / 20% composite material with a uniform HGM volume fraction distribution is shown below. Figure 14 In (c), the HGM is uniformly distributed and relatively dispersed, with fewer pores between HGM particles. The presence of pores within the composite material can significantly improve its thermal insulation capacity; therefore, composite materials with a gradient distribution of HGM volume fraction exhibit better thermal insulation performance than those with a uniform distribution. Furthermore, the composite material with a Fabric / 30% / 20% / 10% distribution demonstrates the best thermal insulation performance.

[0104] As described above, the basic principles, main features, and advantages of the present invention have been well described. The above embodiments and specifications are merely descriptions of preferred embodiments of the present invention, and the present invention is not limited to the above embodiments. Various changes and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit and scope of the present invention should fall within the protection scope defined by the present invention.

Claims

1. A polyester fabric / polyvinyl chloride / hollow microsphere composite material, characterized in that, The composite material comprises a polyester fabric base layer, a polyvinyl chloride (PVC) layer, and hollow glass microspheres dispersed in the PVC layer. The hollow glass microspheres are dispersed in the PVC layer in the form of a particle size gradient distribution or a volume fraction gradient distribution, resulting in pores inside the composite material. The particle size gradient distribution is 70μm / 60μm / 50μm, and the volume fraction gradient distribution is 30% / 20% / 10%.

2. A method for preparing the composite material according to claim 1, characterized in that, Includes the following steps: Step 1: Prepare a polyvinyl chloride-hollow microsphere mixture paste; Step 2: Apply the polyvinyl chloride-hollow microsphere mixture paste prepared in Step 1 onto the polyester fabric using a hand lay-up process and spread it evenly. Step 3: Place the polyester fabric coated with the mixed paste obtained in Step 2 into a drying device and heat it to cure. Step 4: Cut and polish the composite material cured in Step 3 to obtain polyester fabric / polyvinyl chloride-hollow microsphere composite material.

3. The preparation method according to claim 2, characterized in that, The preparation method of the polyvinyl chloride-hollow microsphere mixture includes the following steps: S1. Preparation of polyvinyl chloride resin paste: Polyvinyl chloride paste resin EPVC, tributyl citrate TBC and epoxidized soybean oil ESO are mixed in a mass ratio of 100:130:7 and stirred at the first speed for 30 min to prepare a uniform polyvinyl chloride resin paste mixture. S2. Weigh a certain amount of hollow glass microspheres HGM and add it to the well-stirred polyvinyl chloride resin paste mixture. Stir at a second speed less than the first speed for 60 minutes to obtain a polyvinyl chloride-hollow microsphere mixture paste.

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