A lampshade material and its preparation process

Abstract

This application relates to the field of high-transmittance plastics technology, specifically disclosing a lampshade material and its preparation process. It is prepared by mixing raw materials comprising the following parts by weight: 50-60 parts of polyethylene terephthalate, 3-5 parts of modified polyvinyl alcohol powder, 2-3 parts of polyisobutylene, 1-2 parts of toughening agent, 0.5-1 parts of glyceryl stearate, and 0.2-0.3 parts of compatibilizer. The modified polyvinyl alcohol powder is prepared by hydrophobizing polyvinyl alcohol, dispersing it in a mixed solvent, adding an inhibitor, heating and stirring, then adding glutaraldehyde dropwise, reducing the stirring speed and continuing stirring, vacuum degassing, coating, baking the wet film, storing it in liquid nitrogen, and finally shearing. The modified polyvinyl alcohol powder prepared in this application uses a small amount and can effectively enhance the water vapor barrier ability of polyethylene terephthalate.

Description

Technical Field

[0001] This application relates to the field of high-transmittance plastics technology, and more specifically, to a lampshade material and its preparation process. Background Technology

[0002] In automotive lighting systems, headlights are a critical component, and their performance and reliability directly affect driving safety and the driving experience. Given that headlights face complex and changing environmental conditions during operation, such as high temperatures, ultraviolet radiation, mechanical vibration, and humidity, the use of high-performance lens materials for protection is particularly important to ensure the stable operation of the internal optical components and extend their lifespan.

[0003] Among numerous materials, polyethylene terephthalate (PET) stands out as an ideal raw material for lampshade manufacturing due to its high light transmittance, excellent mechanical strength, and chemical resistance. However, PET materials also have certain limitations in practical applications, especially in environments with high humidity or large temperature differences. PET lampshades are susceptible to moisture penetration and corrosion; moisture condenses into liquid droplets on the inner wall of the lampshade, causing internal fogging and significantly reducing light transmittance. Furthermore, moisture promotes the electrochemical corrosion of the metal coating inside the lampshade, damaging its mirror structure and weakening its reflective and focusing capabilities. This dual effect severely reduces the lampshade's protective effectiveness for the core components of the vehicle headlight, impacting driving safety. Therefore, to improve the moisture barrier properties of PET, multilayer composite films are often used in actual production to enhance the moisture barrier capabilities of the PET material.

[0004] Chinese patent application CN115610056A discloses an improved high-barrier PET composite film. In this design, a PVDC protective layer, a polyvinyl chloride layer, and nano-fluoropolymer particles are sequentially assembled on a PET substrate. Through the synergistic effect of the multi-layered assembled film, the resulting composite material possesses high barrier properties and damage resistance.

[0005] While the aforementioned application documents demonstrate that multilayer film stacking can improve the overall barrier properties of composite materials, the stacking process leads to significant material waste and increases the complexity of composite material molding. Furthermore, the assembly of multiple film components reduces the material's light transmittance, affecting the lampshade's performance. Therefore, there is a need to develop a lampshade material that can reduce the amount of added components while effectively improving the moisture barrier properties of PET. Summary of the Invention

[0006] In order to further reduce the amount of additives used while improving the water vapor barrier ability of PET, this application provides a lampshade material and its preparation process.

[0007] In a first aspect, this application provides a lampshade material prepared by mixing raw materials comprising the following parts by weight: 50-60 parts of polyethylene terephthalate, 3-5 parts of modified polyvinyl alcohol powder, 2-3 parts of polyisobutylene, 1-2 parts of toughening agent, 0.5-1 part of glyceryl stearate, and 0.2-0.3 parts of compatibilizer.

[0008] The preparation steps of the modified polyvinyl alcohol powder include the following:

[0009] [S01] Take polyvinyl alcohol, heat and disperse it, irradiate it for the first time, then pass nitrogen gas through it, add a fluorocarbon source to initiate the treatment, then irradiate it a second time, let it stand, then centrifuge and take the precipitate, and purify it to obtain fluorinated modified polyvinyl alcohol.

[0010] [S02] Take fluorinated modified polyvinyl alcohol, disperse it with a mixed solvent, add an inhibitor, heat and stir, then add glutaraldehyde dropwise, reduce the stirring speed and continue stirring, degas under vacuum and coat the film, bake the wet film and store it in liquid nitrogen, and finally shear it to obtain the final product.

[0011] The polyvinyl alcohol acetoxy group content is 12.7%-15.2%;

[0012] The mixed solvent is obtained by mixing isopropanol and water in a volume ratio of 3:(0.5-1).

[0013] By adopting the above technical solution, polyvinyl alcohol and fluorocarbon source initiation treatment can be used to branch fluorinated alkyl groups on molecular links, and finally fluorinated modified polyvinyl alcohol can be obtained. The hydrophobic effect of polyvinyl alcohol can be improved by the low surface energy of fluorocarbon bond. Further addition of inhibitor treatment can reduce the agglomeration behavior of fluorinated modified polyvinyl alcohol during the coating process, promote the embrittlement process after the wet film dries, and obtain a more dispersed pulverized material after shearing treatment.

[0014] Preferably, in step [S01], the fluorocarbon source is one of trifluoroethyl methacrylate and hexafluorobutyl methacrylate;

[0015] The mass ratio of polyvinyl alcohol to fluorocarbon source used is 5:(0.5-0.6).

[0016] The initial irradiation treatment is performed by setting the power to 100-200W and continuing for 1-1.5 hours.

[0017] The secondary irradiation treatment is performed by setting the power to 350-420W and continuing for 30-45 seconds.

[0018] By employing the aforementioned technical solutions, irradiation and initiation treatment can effectively activate the side chains of polyvinyl alcohol (PVA) and promote the generation of free radicals. These free radicals further react with a fluorocarbon source containing a double bond structure, ultimately achieving the grafting of fluorinated groups onto the PVA side chains. Furthermore, secondary microwave irradiation, by increasing microwave power, can enhance the effective microwave energy absorption rate of the material's local area, accelerating the grafting reaction process and thus significantly improving grafting efficiency.

[0019] Preferably, in step [S02], the preparation step of the inhibitor includes the following: taking microcrystalline cellulose, dispersing it, adding citric acid, carrageenan and polyvinylpyrrolidone, stirring and heating to obtain the inhibitor;

[0020] The mass ratio of the microcrystalline cellulose, citric acid, carrageenan, and polyvinylpyrrolidone used is (2-3):(0.3-0.5):(0.1-0.2):(0.02-0.03).

[0021] The stirring and heating process in the preparation steps of the inhibitor is as follows: adjust the magnetic stirring speed to 100-300 rpm, the temperature to 45-50℃, and process for 1-2 minutes.

[0022] By employing the above technical solution, in the inhibitor system, microcrystalline cellulose can interact with the acetoxy groups on the polyvinyl alcohol (PVA) molecular chains. Through the physical isolation effect of its structure, it effectively blocks the formation of a large-scale hydrogen bond network between fluorinated PVA molecules. Simultaneously, other components of the inhibitor, through synergistic effects such as solvation, further restrict the aggregation behavior of the fluorinated PVA, ensuring its stable dispersion in the mixed solvent as clusters. The addition of the inhibitor weakens the entanglement and aggregation behavior of PVA, promoting the structural embrittlement process during wet film curing. Subsequent shearing treatment yields modified PVA pulverized material, which can be used to assist in constructing a moisture barrier during isothermal kneading.

[0023] Preferably, in step [S02], the mass-to-volume ratio of fluorinated modified polyvinyl alcohol, mixed solvent, inhibitor and glutaraldehyde is 10g:(60-75)ml:(0.4-0.5)g:(0.025-0.05)g.

[0024] By adopting the above technical solution, after the fluorinated modified polyvinyl alcohol is dispersed by the inhibitor, the citric acid in its components can work synergistically with the subsequently added glutaraldehyde to promote the stability of the micro-matrix structure of the fluorinated modified polyvinyl alcohol through aldol condensation in a heated environment.

[0025] Secondly, this application provides a process for preparing a lampshade material, characterized by comprising the following steps:

[0026] (1) Take modified polyvinyl alcohol powder, polyisobutylene and glyceryl stearate and stir to obtain a mixture for later use;

[0027] (2) Take polyethylene terephthalate, toughening agent and compatibilizer, mix them, melt them, knead them at a constant temperature, add the mixture and continue to process, then mold them and cool them to obtain the product;

[0028] The temperature conditions for the constant temperature kneading are 105-125℃.

[0029] By adopting the above technical solution, the modified polyvinyl alcohol powder is dispersed in the composite system under constant temperature and the mechanical action of a kneader. Under residual heat and kneading, the powder is further stretched, increasing the effective barrier area. The modified polyvinyl alcohol powder after kneading and dispersion can form a barrier in the composite system. When external moisture diffuses from the surface of the lampshade material inward, the moisture cannot directly penetrate the powder and can only slowly penetrate into the inner layer of the material in a more tortuous manner, reducing the rate of moisture penetration into the inner layer. The added polyisobutylene and other components can act as elasticizers in the composite system, dispersing the material stress caused by external loads. Through the entanglement effect of the methyl structure enriched by its molecular side chains, it combines with the adjacent modified polyvinyl alcohol powder to promote the formation of a flexible connection network and enhance the mechanical properties of the material.

[0030] In summary, this application has the following beneficial effects:

[0031] 1. This application employs polyvinyl alcohol (PVA) and a fluorocarbon source to initiate treatment, linking fluorinated alkyl groups to the side of the PVA molecule. The low surface energy of the fluorocarbon bond enhances the hydrophobic effect of PVA. After fluorination-modified PVA treatment, it is coated, dried, frozen, and sheared before being mixed with polyisobutylene and other components to obtain a mixture. During kneading and dispersion with the remaining material components, the modified PVA powder is further stretched under residual heat and kneading action, increasing its effective barrier area. The added polyisobutylene and other components act as elastic reinforcements, combining with the modified PVA powder in the dispersion system to promote the formation of a flexible network, compensating for the impact of the powder on the overall mechanical properties of the material. The dispersed modified PVA powder assists in constructing a barrier within the material, preventing water vapor from penetrating into the inner layers. Through the synergistic effect of the various components, the water vapor migration path becomes more tortuous, improving the water vapor barrier performance of PET while reducing the use of additives.

[0032] 2. In this application, an inhibitor is preferably used in combination with glutaraldehyde to promote the embrittlement process of the polyvinyl alcohol film. In the inhibitor system, microcrystalline cellulose can interact with the acetoxy groups on the polyvinyl alcohol molecular chain, effectively blocking the formation of a large-scale hydrogen bond network between fluorinated polyvinyl alcohol molecules through the physical isolation effect of its structure; and through the synergistic effect of solubilization and other components in the inhibitor, the aggregation behavior of fluorinated polyvinyl alcohol is further restricted, so that the fluorinated polyvinyl alcohol is stably dispersed only in the form of clusters in the mixed solvent. Subsequent shearing treatment can yield modified polyvinyl alcohol powder with better dispersion. Attached Figure Description

[0033] Figure 1 The results are the water contact angle test results of the test samples of Examples 2-3 and Comparative Examples 1-3 of this application.

[0034] Figure 2 The results of water vapor transmission rate tests on the test samples of Examples 1-4 and Comparative Examples 1-3 of this application are shown. Detailed Implementation

[0035] The technical solution of the present invention will be explained in detail below with reference to several representative embodiments.

[0036] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0037] Description of raw materials used in the embodiments and comparative examples of this invention:

[0038] Microcrystalline cellulose, aspect ratio ≥ 5;

[0039] Polyethylene terephthalate, industrial grade, molecular weight 30,000-50,000;

[0040] Polyvinyl alcohol, acetoxy group content 12.7%-15.2%, molecular weight 1500-2000;

[0041] Polyisobutylene, with a molecular weight of 30,000-45,000;

[0042] Toughening agent, model MR-502, supplied by Quansheng Polycarbonate Technology Co., Ltd.

[0043] Compatibilizer, model PP-6452, supplied by Shanghai Kaiyin Chemical Co., Ltd.

[0044] Preparation Example 1

[0045] Take 2g of microcrystalline cellulose, add deionized water to prepare a dispersion with a mass concentration of 2.5%, then add 0.3g of citric acid, 0.1g of carrageenan and 0.02g of polyvinylpyrrolidone, adjust the magnetic stirring speed to 100rpm, and treat at 45℃ for 1min to obtain the inhibitor.

[0046] 5g of polyvinyl alcohol (acetoxy content 12.7%) was mixed with 40ml of dimethyl sulfoxide and dispersed at 82℃ for 20min. Then, it was irradiated with microwave at 100W and stirred for 1h. After that, nitrogen gas was purged to remove air, 0.5g of trifluoroethyl methacrylate and 0.05g of potassium persulfate were added. The magnetic stirring speed was adjusted to 100rpm and treated for 10min. After irradiation with microwave at 350W for 30s, the treatment was stopped and allowed to stand for 10min. Then, it was centrifuged at 1000rpm for 30min. After filtration, the precipitate was collected, washed twice with cold water, and naturally cooled under a nitrogen atmosphere to obtain fluorinated modified polyvinyl alcohol.

[0047] Preparation Example 2

[0048] Take 2.4g of microcrystalline cellulose, add deionized water to prepare a dispersion with a mass concentration of 2.5%, then add 0.4g of citric acid, 0.15g of carrageenan and 0.03g of polyvinylpyrrolidone, adjust the magnetic stirring speed to 200rpm, and treat at 45℃ for 2min to obtain the inhibitor.

[0049] 5g of polyvinyl alcohol (acetoxy content 13.5%) was mixed with 40ml of dimethyl sulfoxide and dispersed at 90℃ for 25min. Then, it was irradiated with microwave at 150W and stirred for 1h. After that, nitrogen gas was purged to remove air, 0.5g of hexafluorobutyl methacrylate and 0.1g of potassium persulfate were added. The magnetic stirring speed was adjusted to 100rpm and treated for 15min. After irradiation with microwave at 400W for 40s, the treatment was stopped and allowed to stand for 10min. Then, it was centrifuged at 1500rpm for 30min. After filtration, the precipitate was collected, washed three times with cold water, and naturally cooled under a nitrogen atmosphere to obtain fluorinated modified polyvinyl alcohol.

[0050] Preparation Example 3

[0051] Take 3g of microcrystalline cellulose, add deionized water to prepare a dispersion with a mass concentration of 2.5%, then add 0.5g of citric acid, 0.2g of carrageenan and 0.02g of polyvinylpyrrolidone, adjust the magnetic stirring speed to 300rpm, and treat at 50℃ for 2min to obtain the inhibitor.

[0052] 5g of polyvinyl alcohol (acetoxy content 15.2%) was mixed with 40ml of dimethyl sulfoxide and dispersed at 95℃ for 30min. Then, it was irradiated with microwave at 200W and stirred for 1.5h. After that, nitrogen gas was purged to remove air, 0.6g of hexafluorobutyl methacrylate and 0.1g of potassium persulfate were added. The magnetic stirring speed was adjusted to 200rpm and treated for 20min. After irradiation with microwave at 420W for 45s, the treatment was stopped and allowed to stand for 30min. Then, it was centrifuged at 2000rpm for 30min. After filtration, the precipitate was collected, washed three times with cold water, and naturally cooled under a nitrogen atmosphere to obtain fluorinated modified polyvinyl alcohol.

[0053] Example 1

[0054] Take 30g of modified polyvinyl alcohol powder, 20g of polyisobutylene and 5g of glyceryl stearate, mix them, adjust the magnetic stirring speed to 300rpm, disperse for 5min to obtain the mixture.

[0055] Take 500g of polyethylene terephthalate, mix it with 10g of toughening agent and 2g of compatibilizer, add it to a high-speed mixer and treat for 5 minutes. Then transfer it to a twin-screw extruder, set the barrel temperature to 185℃, 220℃, 255℃, 260℃, 260℃, 265℃, 260℃, and 240℃ in sequence, and the screw speed to 230 rpm. Melt for 30 minutes. Then transfer the molten material to a 105℃ constant temperature kneader, set the motor power to 0.75kW, add the mixture, set the vacuum degree to -0.094MPa, and treat for 1 hour to obtain a mixed rubber. Finally, transfer the mixed rubber to an 82℃ pressure molding machine, set the molding pressure to 10MPa, hold for 20 minutes, and allow it to cool naturally at room temperature to obtain the lampshade material.

[0056] In this embodiment, the preparation steps of the modified polyvinyl alcohol powder are as follows:

[0057] 10g of fluorinated modified polyvinyl alcohol was dispersed in 60ml of mixed solvent, followed by the addition of 0.4g of inhibitor. The system temperature was raised to 80℃, and the magnetic stirring speed was adjusted to 200rpm for 10min. Then, 5ml of 0.5% glutaraldehyde was added dropwise at a rate of 1.2ml / min, and the magnetic stirring speed was reduced to 25rpm for 0.5h. Vacuum degassing was then performed for 5min to obtain a gel. The gel was then coated onto a silicone-coated glass surface using a spin coater at 2000rpm to obtain a wet film thickness of 35μm. The wet film was baked at 60℃ for 10min, then transferred to liquid nitrogen for 1h, and finally processed using a shear mill for 5min to obtain the final product.

[0058] In this embodiment, the fluorinated modified polyvinyl alcohol and the inhibitor were prepared in Preparation Example 1.

[0059] The mixed solvent is obtained by mixing isopropanol and deionized water in a volume ratio of 6:1.

[0060] Example 2

[0061] Take 40g of modified polyvinyl alcohol powder, 25g of polyisobutylene and 8g of glyceryl stearate and mix them. Adjust the magnetic stirring speed to 300rpm and disperse for 6min to obtain the mixture.

[0062] Take 550g of polyethylene terephthalate, mix it with 12g of toughening agent and 2.5g of compatibilizer, add it to a high-speed mixer and treat for 10min. Then transfer it to a twin-screw extruder, set the barrel temperature to 185℃, 220℃, 255℃, 260℃, 260℃, 265℃, 260℃, and 240℃ in sequence, and the screw speed to 250rpm. Melt for 32min. Then transfer the molten material to a 110℃ constant temperature kneader, set the motor power to 0.75kW, add the mixture, set the vacuum degree to -0.094MPa, and treat for 1.2h to obtain a mixed rubber. Finally, transfer the mixed rubber to a 90℃ pressure molding machine, set the molding pressure to 12MPa, hold for 25min, and allow it to cool naturally at room temperature to obtain the lampshade material.

[0063] In this embodiment, the preparation steps of the modified polyvinyl alcohol powder are as follows:

[0064] 10g of fluorinated modified polyvinyl alcohol was dispersed in 65ml of mixed solvent, followed by the addition of 0.5g of inhibitor. The system temperature was raised to 82℃, and the magnetic stirring speed was adjusted to 300rpm for 25min. Then, 7.5ml of 0.5% glutaraldehyde was added dropwise at a rate of 1.8ml / min, and the magnetic stirring speed was reduced to 30rpm for 0.5h. Vacuum degassing was then performed for 15min to obtain a gel. The gel was then coated onto a silicone-coated glass surface using a spin coater at 2500rpm to obtain a wet film with a thickness of 40μm. The wet film was baked at 65℃ for 20min, then transferred to liquid nitrogen for 1.5h, and finally processed using a shear mill for 10min to obtain the final product.

[0065] In this embodiment, the fluorinated modified polyvinyl alcohol and the inhibitor were prepared in Preparation Example 2.

[0066] The mixed solvent is obtained by mixing isopropanol and deionized water in a volume ratio of 3:1.

[0067] Example 3

[0068] Take 50g of modified polyvinyl alcohol powder, 30g of polyisobutylene and 10g of glyceryl stearate and mix them. Adjust the magnetic stirring speed to 300rpm and disperse for 10min to obtain the mixture.

[0069] Take 600g of polyethylene terephthalate, mix it with 20g of toughening agent and 3g of compatibilizer, add it to a high-speed mixer and treat for 20min. Then transfer it to a twin-screw extruder, set the barrel temperature to 185℃, 220℃, 255℃, 260℃, 260℃, 265℃, 260℃ and 240℃ respectively, and the screw speed to 275rpm. Melt for 45min. Then transfer the molten material to a 125℃ constant temperature kneader, set the motor power to 0.75kW, add the mixture, set the vacuum degree to -0.094MPa, and treat for 2h to obtain a mixed rubber. Finally, transfer the mixed rubber to a 95℃ pressure molding machine, set the molding pressure to 15MPa, hold for 30min, and let it cool naturally at room temperature to obtain the lampshade material.

[0070] In this embodiment, the preparation steps of the modified polyvinyl alcohol powder are as follows:

[0071] 10g of fluorinated modified polyvinyl alcohol was dispersed in 75ml of mixed solvent, followed by the addition of 0.5g of inhibitor. The system temperature was raised to 85℃, and the magnetic stirring speed was adjusted to 300rpm for 30min. Then, 10ml of 0.5% glutaraldehyde was added dropwise at a rate of 2.3ml / min, and the magnetic stirring speed was reduced to 50rpm for 1h. Vacuum degassing was then performed for 20min to obtain a gel. The gel was then coated onto a silicone-coated glass surface using a spin coater at 2500rpm to obtain a wet film thickness of 40μm. The wet film was baked at 70℃ for 30min, then transferred to liquid nitrogen for 2h, and finally processed using a shear mill for 10min to obtain the final product.

[0072] In this embodiment, the fluorinated modified polyvinyl alcohol and the inhibitor were prepared in Preparation Example 3.

[0073] The mixed solvent is obtained by mixing isopropanol and deionized water in a volume ratio of 3:1.

[0074] Example 4

[0075] The difference between this embodiment and Embodiment 1 is that the preparation steps of the modified polyvinyl alcohol powder are as follows:

[0076] 10g of fluorinated modified polyvinyl alcohol was dispersed in 72ml of mixed solvent, followed by the addition of 0.5g of inhibitor. The system temperature was raised to 85℃, and the magnetic stirring speed was adjusted to 300rpm for 30min. Then, 5ml of 0.5% glutaraldehyde was added dropwise at a rate of 1.8ml / min, and the magnetic stirring speed was reduced to 25rpm for 45min. Vacuum degassing was then performed for 20min to obtain a gel. The gel was then coated onto a silicone-coated glass surface using a spin coater at 2500rpm to obtain a wet film thickness of 35μm. The wet film was baked at 65℃ for 15min, then transferred to liquid nitrogen for 1h, and finally processed using a shear mill for 6min to obtain the final product.

[0077] In this embodiment, the fluorinated modified polyvinyl alcohol and the inhibitor were prepared in Preparation Example 2.

[0078] The remaining steps are the same as in Example 1.

[0079] Comparative Example 1

[0080] Take 500g of polyethylene terephthalate, mix it with 10g of toughening agent and 2g of compatibilizer, add it to a high-speed mixer and treat for 10min. Then transfer it to a twin-screw extruder, set the barrel temperature to 185℃, 220℃, 255℃, 260℃, 260℃, 265℃, 260℃, and 240℃ in sequence, and the screw speed to 230rpm. Melt for 40min. Then transfer the molten material to a 105℃ constant temperature kneader, set the motor power to 0.75kW, add 45g of polyvinyl alcohol (acetoxy content 12.7%), set the vacuum degree to -0.094MPa, and treat for 1.5h to obtain a mixed rubber. Finally, transfer the mixed rubber to a 90℃ pressure molding machine, set the molding pressure to 12MPa, hold for 20min, and allow it to cool naturally at room temperature to obtain the lampshade material.

[0081] The remaining steps are the same as in Example 1.

[0082] Comparative Example 2

[0083] Take 500g of polyethylene terephthalate, mix it with 10g of toughening agent and 2g of compatibilizer, add it to a high-speed mixer and treat for 5 minutes, then transfer it to a twin-screw extruder, set the barrel temperature to 185℃, 220℃, 255℃, 260℃, 260℃, 265℃, 260℃, and 240℃ in sequence, and the screw speed to 230 rpm, and melt for 30 minutes. Then transfer the molten material to a 105℃ constant temperature kneader, set the motor power to 0.75kW, then add 60g of modified polyvinyl alcohol powder, set the vacuum degree to -0.094MPa, and treat for 1 hour to obtain a mixed rubber. Finally, transfer the mixed rubber to an 82℃ pressure molding machine, set the molding pressure to 10MPa, hold for 20 minutes, and let it cool naturally at room temperature to obtain the lampshade material.

[0084] The remaining steps are the same as in Example 1.

[0085] Comparative Example 3

[0086] The difference between this comparative example and Example 1 is that the preparation steps of the modified polyvinyl alcohol powder are as follows:

[0087] Take 10g of fluorinated modified polyvinyl alcohol and disperse it in 60ml of mixed solvent. Then raise the system temperature to 80℃, adjust the magnetic stirring speed to 200rpm and stir for 15min. Then reduce the magnetic stirring speed to 25rpm and treat for 0.5h. Then vacuum degassing for 5min to obtain the adhesive solution. Then use a spin coater to coat the adhesive solution onto the silicone oil-coated glass surface at 2000rpm to obtain a wet film thickness of 35μm. The wet film is baked at 60℃ for 10min, then transferred to liquid nitrogen for 1h and finally treated with a shear mill for 5min to obtain the final product.

[0088] The remaining steps are the same as in Example 1.

[0089] Performance testing

[0090] Test sample preparation

[0091] The mixed adhesives from Examples 1-4 and Comparative Examples 1-3 were transferred to a cast film extruder. The discharge screw speed was controlled at 120 rpm and the casting roller temperature was 125°C to obtain a cast film. Subsequently, each group of cast film products was placed on a substrate, and the airflow velocity was controlled at 1.5 m / s and the temperature at 42°C. The film was then dried with hot air. Finally, a disc sampler was used to cut the film into discs with a diameter of Φ=50 mm to obtain test samples.

[0092] Apparent performance test

[0093] Table 1 Comparison of Apparent Performance Tests of Examples 1-4 and Comparative Examples 1-3

[0094]

[0095] The test results are shown in Table 2.

[0096] Table 2. Apparent performance test results of Examples 1-4 and Comparative Examples 1-3

[0097]

[0098] Analysis of Examples 1-4 and Comparative Examples 1-3, combined with Table 1-2, shows that Comparative Example 2 exhibits the highest tensile strength and lowest elongation at break, indicating that it is more prone to brittle fracture. This is because Comparative Example 2 directly incorporates modified polyvinyl alcohol pulverized material. Since the pulverized material is dispersed throughout the material, it reduces the overall material's ability to resist energy accumulation through chain transmission, making it more susceptible to damage from external forces. In contrast, Examples 1-3 and Comparative Example 3, due to the addition of elasticizers such as polyisobutylene during the preparation process, can interact with the pulverized material and other components to assist in energy... The yellowing value improves the mechanical properties of the material; the yellowing value can characterize the durability of the material, and the difference between the examples and the comparative examples is large, with a range of 1.2, indicating that the comparative example test samples showed obvious aging behavior; due to the difference in the polyvinyl alcohol treatment method, the aging behavior of the test sample in the test environment of Comparative Example 1 was accelerated; Comparative Example 3 did not add necessary additives such as inhibitors for embrittlement treatment, and the crushing effect after shearing treatment was not good. After the crushed material was mixed into PET, there was a dispersibility problem, which ultimately led to the increase in the yellowing value; among all test groups, Example 2 and Example 3 have better overall properties.

[0099] Water contact angle test

[0100] Referring to the relevant test methods in the national standard GB / T30693-2014, the water contact angle of each test sample from Examples 2-3 and Comparative Examples 1-3 was measured using a contact angle meter. 5 μL of ultrapure water was added to each test sample for each test, and the test was repeated three times for each group of test samples, with the average value taken.

[0101] Test results are as follows Figure 1 As shown.

[0102] Analysis of Examples 2-3 and Comparative Examples 1-3 in conjunction with Figure 1It can be seen that the modified polyvinyl alcohol powder prepared in the examples, when incorporated into the PET system and kneaded and dispersed, can significantly improve the hydrophobic properties of the material, resulting in a certain degree of hydrophobicity. After fluorination modification, the modified polyvinyl alcohol powder has a lower surface energy, and after dispersion, it can inhibit water molecule adhesion through its hydrophobic structure on the surface of the material, achieving a water-blocking effect. Among all test groups, Comparative Example 3, due to uneven mixing and dispersion, had difficulty in uniformly distributing the fluorinated modified polyvinyl alcohol on the surface of the test sample, thus slightly reducing the material's water contact angle. Comparative Example 1, which directly incorporated polyvinyl alcohol into the system, further reduced the material's water-blocking ability due to the hydrophilic structure of polyvinyl alcohol itself, making it easier to be wetted by water, resulting in the worst water-blocking effect.

[0103] Water vapor barrier test

[0104] Referring to the national standard GB / T1037-2021, the water vapor transmission rate of the test samples of Examples 1-4 and Comparative Examples 1-3 was tested. The test conditions were set as follows: temperature 23.0℃±0.5℃, relative humidity 90%±2%.

[0105] Test results are as follows Figure 2 As shown.

[0106] Analysis of Examples 1-4 and Comparative Examples 1-3 in conjunction with Figure 2 It can be seen that the water vapor transmission rate of the test group in the example was significantly lower than that in the comparative example, indicating that the water vapor barrier performance of the material using the example scheme is excellent. This is because the example scheme, with its dispersed modified polyvinyl alcohol pulverized material forming a barrier against the external water vapor environment, prevents water vapor molecules from directly penetrating the pulverized material when they reach it. Instead, the water vapor molecules bypass the pulverized material and diffuse into the inner layer of the material, thus extending the water vapor migration path and ultimately improving the material's water vapor barrier effect. In contrast, the test results of Comparative Example 1 are completely opposite to those of the example scheme. Due to the introduction of hydrophilic polyvinyl alcohol, it actually promotes the further penetration of water vapor from the material surface into the interior, greatly reducing the water vapor barrier capacity. Comparative Example 3, due to the lack of inhibitors, has a lower degree of modified polyvinyl alcohol pulverization, resulting in an incomplete water vapor barrier and therefore a less effective water vapor barrier than the example.

[0107] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A lampshade material, characterized in that, It is prepared by mixing the following raw materials in parts by weight: 50-60 parts of polyethylene terephthalate, 3-5 parts of modified polyvinyl alcohol powder, 2-3 parts of polyisobutylene, 1-2 parts of toughening agent, 0.5-1 part of glyceryl stearate, and 0.2-0.3 parts of compatibilizer; The preparation steps of the modified polyvinyl alcohol powder include the following: [S01] Take polyvinyl alcohol, heat and disperse it, irradiate it for the first time, then pass nitrogen gas through it, add a fluorocarbon source to initiate the treatment, then irradiate it a second time, let it stand, then centrifuge and take the precipitate, and purify it to obtain fluorinated modified polyvinyl alcohol. [S02] Take fluorinated modified polyvinyl alcohol, disperse it with a mixed solvent, add an inhibitor, heat and stir, then add glutaraldehyde dropwise, reduce the stirring speed and continue stirring, degas under vacuum and coat the film, bake the wet film and store it in liquid nitrogen, and finally shear it to obtain the final product. The preparation steps of the inhibitor include the following: take microcrystalline cellulose, disperse it, add citric acid, carrageenan and polyvinylpyrrolidone, stir and heat to obtain the inhibitor; The mass ratio of the microcrystalline cellulose, citric acid, carrageenan, and polyvinylpyrrolidone used is (2-3):(0.3-0.5):(0.1-0.2):(0.02-0.03). The stirring and heating process in the preparation steps of the inhibitor is as follows: adjust the magnetic stirring speed to 100-300 rpm, the temperature to 45-50℃, and process for 1-2 minutes.

2. The lampshade material according to claim 1, characterized in that, In step [S01], the polyvinyl alcohol acetoxy content is 12.7%-15.2%.

3. The lampshade material according to claim 1, characterized in that, In step [S01], the fluorocarbon source is one of trifluoroethyl methacrylate and hexafluorobutyl methacrylate.

4. The lampshade material according to claim 1, characterized in that, In step [S01], the mass ratio of polyvinyl alcohol to fluorocarbon source is 5:(0.5-0.6).

5. The lampshade material according to claim 1, characterized in that, In step [S01], the initial irradiation treatment is performed by setting the power to 100-200W and continuing for 1-1.5 hours. The secondary irradiation treatment is performed by setting the power to 350-420W and continuing for 30-45 seconds.

6. The lampshade material according to claim 1, characterized in that, In step [S02], the mixed solvent is obtained by mixing isopropanol and water in a volume ratio of 3:(0.5-1).

7. The lampshade material according to claim 1, characterized in that, In step [S02], the mass-volume ratio of fluorinated modified polyvinyl alcohol, mixed solvent, inhibitor and glutaraldehyde is 10g:(60-75)ml:(0.4-0.5)g:(0.025-0.05)g.

8. A process for preparing a lampshade material, using a lampshade material according to any one of claims 1-7, characterized in that, Includes the following steps: (1) Take modified polyvinyl alcohol powder, polyisobutylene and glyceryl stearate and stir to obtain a mixture for later use; (2) Take polyethylene terephthalate, toughening agent and compatibilizer, mix them, melt them, knead them at a constant temperature, add the mixture and continue to process, then mold them and cool them to obtain the product.

9. The manufacturing process of a lampshade material according to claim 8, characterized in that, The temperature conditions for the constant temperature kneading are 105-125℃.

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