PVB (polyvinyl butyral) film as well as preparation method and application thereof

Abstract

The invention relates to the technical field of laminated glass functional materials, in particular to a PVB (Polyvinyl Butyral) film as well as a preparation method and application thereof. The PVB film comprises a first PVB layer, a middle sound insulation and heat insulation visual optimization layer and a second PVB layer which are sequentially stacked. Wherein the first PVB layer and the second PVB layer comprise a high-butyl PVB base material, an ultraviolet light absorber, a silane coupling agent, an antioxidant and a plasticizer; the middle sound insulation and heat insulation visual optimization layer comprises basic PVB resin, sound insulation type PVB resin, a plasticizer, indium tin oxide slurry and an indole compound. The invention provides a comprehensive PVB film solution with high light resistance, heat and humidity resistance, excellent sound insulation and heat insulation, excellent mechanical strength and visual optimization through an innovative three-layer structural design and an accurate component proportion.

Description

Technical Field

[0001] This invention relates to the field of functional materials technology for laminated glass, and in particular to a PVB film, its preparation method, and its application. Background Technology

[0002] With the increasing demands for energy efficiency, quiet operation, and visual comfort in the automotive and construction industries, the functions of PVB (polyvinyl butyral) films used in laminated glass are becoming increasingly diversified. Currently, to simultaneously achieve sound insulation and heat insulation, the industry commonly attempts to add indium tin oxide (ITO) slurry to PVB films. However, ITO nanoparticles are difficult to disperse uniformly in the PVB resin matrix and are prone to agglomeration, forming localized high-concentration areas. This agglomeration leads to significant visual defects in laminated glass, typically manifested as a "blue hue" cast, resulting in a visual color difference (ΔE) often exceeding 3.0. Simultaneously, light scattering at the agglomerated particles causes increased haze, often reaching 2.0% or higher, severely affecting the uniformity of light transmission and visual clarity. This is unacceptable for applications with high visual safety requirements, such as automotive windshields.

[0003] To address these issues, some solutions have attempted to introduce organic dyes to adjust visual color differences. However, these dyes are prone to degradation under long-term ultraviolet radiation, leading to poor lightfastness and failing to meet long-term weather resistance requirements. Furthermore, some solutions have tried adding additives to improve ITO dispersion, but these additives tend to conflict with the damping and sound insulation system of PVB films, resulting in a significant decrease in the film's weighted sound insulation (RW value), sacrificing its core sound insulation performance. Summary of the Invention

[0004] The purpose of this invention is to address the problems existing in the prior art by providing a PVB film, its preparation method, and its application. Through an innovative three-layer structure design and precise component ratio, it provides a comprehensive PVB film solution that combines high light and humidity resistance, excellent sound and heat insulation, superior mechanical strength, and visual optimization.

[0005] To achieve the above objectives, the present invention provides a PVB film comprising a first PVB layer, an intermediate sound insulation and heat insulation visual optimization layer, and a second PVB layer stacked sequentially. The first PVB layer and the second PVB layer, by weight, respectively comprise: 100 parts of high-butyl PVB substrate, 0.01 to 0.8 parts of ultraviolet absorber, 0.05 to 0.5 parts of silane coupling agent, 0.05 to 0.3 parts of antioxidant, and 35 to 50 parts of plasticizer; The intermediate sound insulation, heat insulation, and visual optimization layer, by weight, includes: 100 parts of base PVB resin, 10-25 parts of sound-insulating PVB resin, 20-60 parts of plasticizer, 0.1-5 parts of indium tin oxide paste, and 0.05-0.5 parts of indole compound.

[0006] Preferably, the total thickness of the PVB film is 0.38~2.0mm; the thickness ratio of the first PVB layer, the intermediate sound insulation and heat insulation visual optimization layer, and the second PVB layer is 30~45:10~40:30~45.

[0007] Preferably, the high-butyl PVB substrate has a butyraldehyde condensation degree of 75-85 mol%, a vinyl alcohol unit content of 12-20 mol%, and a residual acetate unit content of less than or equal to 2 mol.

[0008] Preferably, the butyraldehyde condensation degree of the base PVB resin is 60-78 mol%, the vinyl alcohol unit content is 10-25 mol%, and the residual acetate unit content is less than or equal to 15 mol%. The butyraldehyde condensation degree of sound-insulating PVB resin is 55~75 mol; the vinyl alcohol unit content of sound-insulating PVB resin is higher than that of basic PVB resin, and the difference in vinyl alcohol unit content between sound-insulating PVB resin and basic PVB resin is 5~15 mol.

[0009] Preferably, the sound-insulating PVB resin has a particle size of 10-50 micrometers and a particle size distribution range of less than or equal to 2.0. The particle size of indium tin oxide in the indium tin oxide paste is 10~50nm, and the solid content of the indium tin oxide paste is 20~40%.

[0010] Preferably, the indole compound includes one or more of 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol, 2-2-hydroxy-5-benzylmethylbenzotriazole, 2-(2H-benzotriazol-2-yl)-4-methyl-6-(2-propenyl)phenol, and 2,4-di-tert-butyl-6-(5-chloro-2H-benzotriazol-2-yl)phenol.

[0011] The present invention also provides a method for preparing the aforementioned PVB film, comprising the following steps: S1. Mix the components contained in the middle sound insulation, heat insulation and visual optimization layer to obtain the middle layer premix; S2. The components contained in the first PVB layer, the intermediate premix, and the components contained in the second PVB layer are co-extruded to obtain a PVB film.

[0012] Preferably, in S1, the mixing temperature is 85~95℃ and the mixing time is 15~25min.

[0013] Preferably, in S2, during the co-extrusion process, the barrel temperatures corresponding to the components contained in the first PVB layer and the components contained in the second PVB layer are 150~180℃, and the barrel temperature corresponding to the intermediate layer premix is ​​140~170℃.

[0014] The present invention also provides the application of the PVB film or the PVB film prepared according to the preparation method of the PVB film in laminated glass.

[0015] The beneficial effects of this invention are as follows: 1. This invention provides a PVB film comprising a first PVB layer, a middle sound insulation, heat insulation, and visual optimization layer, and a second PVB layer stacked sequentially. This three-layer composite structure achieves synergistic effects through specialized division of labor: the first and second PVB layers primarily provide mechanical strength and weather resistance, while the middle layer is specifically responsible for sound insulation, heat insulation, and visual optimization, forming a comprehensive solution integrating five functions: strength, sound insulation, heat insulation, weather resistance, and visual appeal. The resulting PVB film maintains excellent mechanical properties while also possessing superior sound and heat insulation effects and visual comfort.

[0016] Furthermore, this invention introduces an indole compound into the intermediate layer. Through its dual mechanism of "inhibiting ITO aggregation" and "adjusting refractive index," it solves the problems of "blue hue shift" and "haze" caused by the addition of ITO nanoparticles. The indole compound can coordinate with the surface of ITO nanoparticles, effectively preventing localized uneven light transmission caused by their aggregation; at the same time, the addition of the indole compound also reduces interfacial light reflection. Experimental data confirms that the haze of the PVB film of this invention is less than or equal to 1.5%, the visual color difference is less than or equal to 2.0, and the light transmission uniformity is excellent, fully meeting the stringent requirements of high-precision vision applications such as automotive windshields.

[0017] 2. Through the synergistic effect of the base PVB resin and sound-insulating PVB resin in the intermediate layer, combined with uniformly dispersed ITO nanoparticles, excellent sound and heat insulation effects are achieved. Test results show that the weighted sound insulation RW of the PVB film of this invention is greater than or equal to 36dB, the infrared blocking rate is greater than or equal to 80%, and the damping coefficient of the intermediate layer is greater than or equal to 0.35, fully meeting the stringent requirements of high-end applications for quiet operation and energy saving.

[0018] 3. High-butyl PVB is used as the surface substrate. By controlling its molecular structure parameters, the high strength and high stability of the material are ensured. Examples show a surface tensile strength greater than or equal to 30 MPa and an interlayer peel strength greater than or equal to 18 N / 25 mm. After 1000 hours of humid heat cycling at 50°C / 95%RH, the adhesion strength retention rate to glass is greater than or equal to 85%, demonstrating excellent environmental durability.

[0019] 4. The surface UV absorber and the intermediate indole compound constitute a highly efficient weather-resistant system. The conjugated structure of the indole compound helps to capture free radicals, significantly reducing the degradation of ITO and PVB matrices by UV radiation. After 2000 hours of irradiation with a 750W quartz mercury lamp, the visible light transmittance change rate is less than or equal to 6.5%, the haze change is less than or equal to 0.3%, and the color difference change is small, demonstrating its optical stability under long-term use.

[0020] 5. The component system used in this invention has excellent compatibility and there is no risk of phase separation; at the same time, the invention ensures that the components are fully dispersed and firmly bonded between layers through a specific preparation process, and has good prospects for industrialization.

[0021] In summary, this invention provides a comprehensive PVB film solution that combines high light and humidity resistance, excellent sound and heat insulation, superior mechanical strength, and visual optimization through an innovative three-layer structure design and precise component ratio. Detailed Implementation

[0022] This invention provides a PVB film, comprising a first PVB layer, an intermediate sound insulation and heat insulation visual optimization layer, and a second PVB layer stacked sequentially. The first PVB layer and the second PVB layer, by weight, respectively comprise: 100 parts of high-butyl PVB substrate, 0.01 to 0.8 parts of ultraviolet absorber, 0.05 to 0.5 parts of silane coupling agent, 0.05 to 0.3 parts of antioxidant, and 35 to 50 parts of plasticizer; The intermediate sound insulation, heat insulation, and visual optimization layer, by weight, includes: 100 parts of base PVB resin, 10-25 parts of sound-insulating PVB resin, 20-60 parts of plasticizer, 0.1-5 parts of indium tin oxide paste, and 0.05-0.5 parts of indole compound.

[0023] In this invention, the total thickness of the PVB film is 0.38~2.0mm; the thickness ratio of the first PVB layer, the intermediate sound insulation and heat insulation visual optimization layer, and the second PVB layer is 30~45:10~40:30~45.

[0024] In this invention, the butyraldehyde condensation degree of the high-butyl PVB substrate is 75-85 mol%, the ethylene alcohol unit content is 12-20 mol%, and the residual acetate unit content is less than or equal to 2 mol.

[0025] In this invention, the ultraviolet absorber includes one or more of UV-1577, UV-1164, UV-400, UV-405, UV-1600, UV-479, UV-477, UV-460, UV-425, and triazine-5.

[0026] In this invention, the silane coupling agent includes γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0027] In this invention, the antioxidant includes antioxidant 1010.

[0028] In this invention, the plasticizer in the first PVB layer and the second PVB layer includes triethylene glycol diisooctanoate.

[0029] In this invention, the butyraldehyde condensation degree of the base PVB resin is 60-78 mol%, the vinyl alcohol unit content is 10-25 mol%, and the residual acetate unit content is less than or equal to 15 mol.

[0030] In this invention, the preparation method of the sound-insulating PVB resin includes the following steps: Polyvinyl alcohol (PVA) is pulverized by freeze drying to obtain powder with a particle size of 80-100 mesh. Pure water (450-550 parts by weight) is added to a reaction vessel, heated to 25-35°C, and stirring is started to form a vortex. PVA powder (80-120 parts by weight) is added, followed by 250-450 parts by weight of pure water. The inner wall is rinsed with a small amount of pure water (1-3 parts by weight). The mixture is stirred at 98-100°C for 1-2 hours to completely dissolve the PVA and obtain a PVA solution. The solution was cooled to 15-50°C, and 18-22 parts by weight of a 18-22% hydrochloric acid solution were added as a catalyst. The temperature was further lowered to 15-35°C, and the following materials were added: 40-50 parts by weight of butyraldehyde, 0.1-5 parts by weight of surfactant (OP-10), and 0.3-10 parts by weight of phase transfer agent (tetrabutylsodium bromide). The reaction was maintained at this temperature for 0.5-1.5 hours, and then the temperature was raised to 38-75°C. Based on the pH change of the reaction system, butyraldehyde and a 18-22% hydrochloric acid solution were added to maintain the pH value between 3.8 and 5, and the reaction was maintained at this temperature for 0-1.5 hours. Finally, an alkaline substance (28-32% NaOH solution) was added to adjust the pH to above 8, the reaction was terminated, and the solution was heated to 40-75°C. The obtained sample was then centrifuged and air-dried sequentially to obtain sound-insulating PVB resin.

[0031] In this invention, the butyraldehyde condensation degree of the sound-insulating PVB resin is 55-75 mol; the vinyl alcohol unit content of the sound-insulating PVB resin is higher than that of the basic PVB resin, and the difference in vinyl alcohol unit content between the sound-insulating PVB resin and the basic PVB resin is 5-15 mol.

[0032] In this invention, the particle size of the sound-insulating PVB resin is 10~50 micrometers, and the particle size distribution span ((D90-D10) / D50) is less than or equal to 2.0.

[0033] In this invention, the preparation method of indium tin oxide paste includes the following steps: Indium tin oxide, N-aminoethylpiperazine (AEP), 2-ethylhexanoic acid, acetylacetone, ethanol and triethylene glycol diisooctanoate (3G8) were mixed and ground at 12-16 r / s for 8-12 h using zirconia beads with a diameter of 0.1-0.3 mm as the grinding medium to obtain indium tin oxide slurry.

[0034] In this invention, the mass ratio of indium tin oxide, AEP, 2-ethylhexanoic acid, acetylacetone, ethanol and 3G8 is 8~12:0.5~1.5:1~3:2~4:3~5:75~85.

[0035] In this invention, the particle size of indium tin oxide in the indium tin oxide paste is 10~50nm, and the solid content (mass fraction of solid matter in the indium tin oxide paste) is 20~40%.

[0036] In this invention, the plasticizer in the intermediate sound insulation, heat insulation and visual optimization layer includes polyethylene glycol bis-2-ethylhexanoate, 4,5-epoxytetrahydrophthalic acid diglycidyl ester or triethylene glycol diisooctanoate, and the average degree of polymerization of polyethylene glycol bis-2-ethylhexanoate is 5 to 9.

[0037] In this invention, the indole compound includes one or more of 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol, 2-2-hydroxy-5-benzylmethylbenzotriazole, 2-(2H-benzotriazol-2-yl)-4-methyl-6-(2-propenyl)phenol, and 2,4-di-tert-butyl-6-(5-chloro-2H-benzotriazol-2-yl)phenol.

[0038] The present invention also provides a method for preparing the aforementioned PVB film, comprising the following steps: S1. Mix the components contained in the middle sound insulation, heat insulation and visual optimization layer to obtain the middle layer premix; S2. The components contained in the first PVB layer, the intermediate premix, and the components contained in the second PVB layer are co-extruded to obtain a PVB film.

[0039] In this invention, in S1, the mixing temperature is 85~95℃ and the mixing time is 15~25min.

[0040] In this invention, during the co-extrusion process in S2, the barrel temperatures corresponding to the components contained in the first PVB layer and the components contained in the second PVB layer are 150~180℃, respectively, and the barrel temperature corresponding to the intermediate layer premix is ​​140~170℃.

[0041] The present invention also provides the application of the PVB film or the PVB film prepared according to the preparation method of the PVB film in laminated glass.

[0042] The present invention also provides a laminated glass comprising two or more glass substrates and a functional interlayer (PVB film) sandwiched between adjacent glass substrates; the laminated glass is obtained by hot pressing at a temperature of 120~150℃ and a pressure of 0.3~0.5MPa.

[0043] The present invention will be further described below with reference to embodiments. Unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art. The features mentioned above or in the specific examples mentioned in this invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the invention and are not intended to limit the scope of the invention.

[0044] In the following embodiments and comparative examples of the present invention, the high-butyl PVB substrate and the basic PVB resin were provided by Anhui Wanwei Group Co., Ltd. In the preparation of sound-insulating PVB resin, the PVA used is PVA2488 from Chongqing Chuanwei Chemical Co., Ltd. of China Petrochemical Corporation. The preparation method specifically includes the following steps: Polyvinyl alcohol (PVA) is pulverized by freeze-drying to obtain powder with a particle size of 90 mesh; pure water (500 parts by weight) is added to the reaction vessel, heated to 30°C and stirred to form a vortex, PVA powder (100 parts by weight) is added, followed by 350 parts by weight of pure water, and the inner wall is rinsed with a small amount of pure water (2 parts by weight). The mixture is stirred at 99°C for 1.5 hours to completely dissolve the PVA and obtain a PVA solution. The solution was cooled to 50°C, and 20 parts by weight of a 20% hydrochloric acid solution were added as a catalyst. The temperature was further lowered to 25°C, and the following materials were added: 45 parts by weight of butyraldehyde, 2 parts by weight of surfactant (OP-10), and 5 parts by weight of phase transfer agent (tetrabutylsodium bromide). The reaction was maintained at this temperature for 1 hour, and then the temperature was raised to 50°C. Based on the pH change of the reaction system, 3 parts by weight of butyraldehyde and 3 parts by weight of a 20% hydrochloric acid solution were added to maintain the pH value of the system between 3.8 and 5. The reaction was maintained at this temperature for 0.5 hours. Finally, an alkaline substance (30% NaOH solution) was added to adjust the pH to 8.5, the reaction was terminated, and the solution was heated to 60°C. The obtained sample was then centrifuged and air-dried to obtain sound-insulating PVB resin.

[0045] The preparation method of indium tin oxide paste includes the following steps: mixing indium tin oxide, N-aminoethylpiperazine (AEP), 2-ethylhexanoic acid, acetylacetone, ethanol and triethylene glycol diisooctanoate (3G8), using zirconia beads with a diameter of 0.2 mm as the grinding medium, and grinding at 14 r / s for 10 h to obtain indium tin oxide paste; wherein, the mass ratio of indium tin oxide, AEP, 2-ethylhexanoic acid, acetylacetone, ethanol and 3G8 is 10:1:2:3:4:80.

[0046] Example 1 This embodiment provides a PVB film (thickness of 0.76 mm), comprising a first PVB layer, an intermediate sound insulation, heat insulation, and visual optimization layer, and a second PVB layer stacked sequentially (thickness ratio of 35.5:28.9:35.5).

[0047] The first PVB layer and the second PVB layer, by weight, each comprise: 100 parts of high-butyl PVB substrate (butyraldehyde condensation degree of 80 mol%, ethylene alcohol unit content of 18 mol%, and residual acetate unit content of 2 mol%), 0.2 parts of ultraviolet absorber (UV-1577), 0.15 parts of silane coupling agent (γ-(2,3-epoxypropoxy)propyltrimethoxysilane), 0.1 parts of antioxidant (antioxidant 1010), and 42 parts of plasticizer (triethylene glycol diisooctanoate).

[0048] The intermediate sound insulation and heat insulation visual optimization layer, by weight, includes: 100 parts of base PVB resin (butyraldehyde condensation degree of 75 mol%, vinyl alcohol unit content of 10 mol%, residual acetate unit content of 13 mol%), 15 parts of sound-insulating PVB resin (butyraldehyde condensation degree of 70 mol%, vinyl alcohol unit content of 15 mol%, particle size of 30 micrometers, particle size distribution span of 2.0%), 35 parts of plasticizer (triethylene glycol diisooctanoate), 1.5 parts of indium tin oxide paste (indium tin oxide paste with indium tin oxide particle size of 25 nm and solid content of 30%), and 0.3 parts of indole compound (2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol).

[0049] This embodiment also provides a method for preparing the above-mentioned PVB film, including the following steps: The base PVB resin, sound-insulating PVB resin, plasticizer, indium tin oxide paste, and indole compound are mixed at 90°C for 20 minutes to obtain the intermediate layer premix.

[0050] The components of the first PVB layer, the intermediate layer premix, and the components of the second PVB layer are fed into the barrel of a three-layer co-extruder. The barrel temperature corresponding to the components of the first and second PVB layers is set to 165°C, and the barrel temperature corresponding to the intermediate layer premix is ​​set to 155°C, to obtain PVB film.

[0051] Example 2 This embodiment provides a PVB film (1.14 mm thick), comprising a first PVB layer, an intermediate sound insulation, heat insulation, and visual optimization layer, and a second PVB layer stacked sequentially (thickness ratio of 35.1:29.8:35.1).

[0052] The first PVB layer and the second PVB layer, by weight, each comprise: 100 parts of high-butyl PVB substrate (butyraldehyde condensation degree of 82 mol%, ethylene alcohol unit content of 16 mol%, and residual acetate unit content of 2 mol%), 0.4 parts of ultraviolet absorber (UV-1164), 0.2 parts of silane coupling agent (γ-(2,3-epoxypropoxy)propyltrimethoxysilane), 0.2 parts of antioxidant (antioxidant 1010), and 42 parts of plasticizer (triethylene glycol diisooctanoate).

[0053] The intermediate sound insulation and heat insulation visual optimization layer, by weight, comprises: 100 parts of base PVB resin (butyraldehyde condensation degree of 70 mol%, vinyl alcohol unit content of 15 mol%, residual acetate unit content of 7 mol%), 20 parts of sound-insulating PVB resin (butyraldehyde condensation degree of 62 mol%, vinyl alcohol unit content of 20 mol%, particle size of 25 micrometers, particle size distribution span of 2.0%), 35 parts of plasticizer (triethylene glycol diisooctanoate), 2.5 parts of indium tin oxide paste (indium tin oxide paste with indium tin oxide particle size of 25 nm and solid content of 30%), and 0.25 parts of indole compound (2-2-hydroxy-5-benzylbenzotriazole).

[0054] This embodiment also provides a method for preparing the above-mentioned PVB film, including the following steps: The base PVB resin, sound-insulating PVB resin, plasticizer, indium tin oxide paste, and indole compound are mixed at 95°C for 20 minutes to obtain the intermediate layer premix.

[0055] The components of the first PVB layer, the intermediate layer premix, and the components of the second PVB layer are fed into the barrel of a three-layer co-extruder. The barrel temperature corresponding to the components of the first and second PVB layers is set to 165°C, and the barrel temperature corresponding to the intermediate layer premix is ​​set to 155°C, to obtain PVB film.

[0056] Comparative Example 1 This comparative example provides a PVB film that differs from Example 1 in that it omits the indole compound in the intermediate sound insulation, heat insulation, and visual optimization layer.

[0057] Comparative Example 2 This comparative example provides a PVB film that differs from Example 1 in that the weight percentage of indole compound in the intermediate sound insulation, heat insulation, and visual optimization layer is modified to 0.8 parts.

[0058] Experimental Example 1 The PVB films used in Examples 1-2 and Comparative Examples 1-2 were subjected to visual performance tests. Haze and initial visible light transmittance tests were conducted according to GB / T 2410-2008, and visual color difference was also tested. Measurements were taken according to GB / T7921-2014 standard under D65 light source and 10° viewing angle conditions. Test results show that the PVB film in Example 1 has a haze of 1.2% and a visual color difference of... (No blue hue), initial visible light transmittance 89.8%; In Example 2, the PVB film exhibited superior visual performance, with a haze of 1.0% and visual color difference. The initial visible light transmittance was 89.0%; while in Comparative Example 1 (without added indole compounds), the PVB film had a haze of 2.4% (with a noticeable hazy appearance), and visual color difference. (Blue hue bias), initial visible light transmittance 88.5%; In Comparative Example 2 (excess indole compound), although the PVB film had a haze of 1.1% and an initial visible light transmittance of 88.2%, the film was noticeably yellowish, with visual color difference. (Exceeds visual requirements).

[0059] Experimental Example 2 The PVB films from Examples 1-2 and Comparative Examples 1-2 were subjected to lightfastness tests. After being irradiated with a 750W quartz mercury lamp for 2000 hours, the color difference change (before and after irradiation) was measured. Difference), visible light transmittance change rate ((visible light transmittance before irradiation - visible light transmittance after irradiation) ÷ visible light transmittance before irradiation) The color difference of the PVB film in Example 1 was 3.6%, the visible light transmittance change rate was 5.6%, and the haze change rate was 0.2%, respectively, calculated by comparing the changes in color difference (100%) and haze (difference before and after irradiation). In Example 2, the color difference of the PVB film was 3.4%, the visible light transmittance change rate was 5.3%, and the haze change rate was 0.1%. In Comparative Example 1 (without indole compound), the color difference of the PVB film was 3.7. In Comparative Example 2 (with excess indole compound), the color difference of the PVB film was 6.2. These results fully verify that by controlling the indole compound within a suitable addition range, the present invention can significantly improve the lightfastness of PVB film while maintaining excellent optical performance under long-term illumination conditions.

[0060] Experimental Example 3 After 1000 hours of humid heat cycling at 50℃ and 95% relative humidity (RH), the adhesion strength retention rate between the PVB film and float glass was tested according to GB / T 15763.3-2009 standard. The results showed that the adhesion strength retention rate of the PVB film in Example 1 reached 92%, and the retention rate of the PVB film in Example 2 was even higher, reaching 94%. In contrast, the adhesion strength retention rate of the PVB film in Comparative Example 1 was 83%, and the retention rate of the PVB film in Comparative Example 2 was 84%. This indicates that compared with the comparative examples, the PVB film prepared in the embodiments of the present invention can still maintain excellent interfacial adhesion stability under harsh humid heat environment.

[0061] Experiment Example 4 The damping coefficient of the intermediate sound insulation and heat insulation visual optimization layer was measured under test conditions of 25℃ and 100Hz. The results showed that the damping coefficient of the intermediate layer in Example 1 was 0.40, and that in Example 2 it reached 0.42, indicating that the intermediate sound insulation and heat insulation visual optimization layer material of the present invention has excellent vibration energy dissipation ability.

[0062] The sound and heat insulation performance of PVB film was tested (weighted sound insulation RW according to GB / T 19889.3-2005, and infrared blocking rate measured in the 2500-25000nm band according to GB / T 2680-2021). The results showed that the RW value of the PVB film in Example 1 was 37.5dB, and the infrared blocking rate reached 86%; the performance of Example 2 was even more outstanding, with the RW value increasing to 38.2dB and the infrared blocking rate reaching 89%. In comparison, the RW value of Comparative Example 1 (without indole compound) was 37.3dB, and the infrared blocking rate was 85%; the RW value of Comparative Example 2 (with excess indole compound) decreased to 37.1dB, and the infrared blocking rate was 84%. This verifies that the present invention achieves a more efficient infrared blocking effect while maintaining excellent sound insulation performance by precisely controlling the amount of indole compound added.

[0063] Experimental Example 5 The strength of the PVB film was tested according to GB / T 2790-1995 standard. The tensile strength of the film surface in Example 1 was 32 MPa and the peel strength was 21.5 N / 25 mm. The tensile strength of the film surface in Example 2 was increased to 34 MPa and the peel strength reached 23.5 N / 25 mm. The tensile strength of the film surface in Comparative Example 1 was 32 MPa and the tensile strength of the film surface in Comparative Example 2 was 31 MPa.

[0064] Therefore, this invention uses the aforementioned PVB film, through an innovative three-layer structure design and precise component ratio, to provide a comprehensive PVB film solution that combines high light and humidity resistance, excellent sound and heat insulation, superior mechanical strength, and visual optimization.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A PVB film, characterized in that, It includes a first PVB layer, an intermediate sound insulation and heat insulation visual optimization layer, and a second PVB layer, which are stacked in sequence. The first PVB layer and the second PVB layer, by weight, respectively comprise: 100 parts of high-butyl PVB substrate, 0.01 to 0.8 parts of ultraviolet absorber, 0.05 to 0.5 parts of silane coupling agent, 0.05 to 0.3 parts of antioxidant, and 35 to 50 parts of plasticizer; The intermediate sound insulation, heat insulation, and visual optimization layer, by weight, includes: 100 parts of base PVB resin, 10-25 parts of sound-insulating PVB resin, 20-60 parts of plasticizer, 0.1-5 parts of indium tin oxide paste, and 0.05-0.5 parts of indole compound.

2. The PVB film according to claim 1, characterized in that, The total thickness of the PVB film is 0.38~2.0mm; the thickness ratio of the first PVB layer, the middle sound insulation and heat insulation visual optimization layer, and the second PVB layer is 30~45:10~40:30~45.

3. The PVB film according to claim 1, characterized in that, The high-butyl PVB substrate has a butyraldehyde condensation degree of 75-85 mol%, a vinyl alcohol unit content of 12-20 mol%, and a residual acetate unit content of less than or equal to 2 mol.

4. The PVB film according to claim 1, characterized in that, The basic PVB resin has a butyraldehyde condensation degree of 60-78 mol%, a vinyl alcohol unit content of 10-25 mol%, and a residual acetate unit content of less than or equal to 15 mol%. The butyraldehyde condensation degree of sound-insulating PVB resin is 55~75 mol; the vinyl alcohol unit content of sound-insulating PVB resin is higher than that of basic PVB resin, and the difference in vinyl alcohol unit content between sound-insulating PVB resin and basic PVB resin is 5~15 mol.

5. The PVB film according to claim 1, characterized in that, The particle size of the sound-insulating PVB resin is 10~50 micrometers, and the particle size distribution range is less than or equal to 2.

0. The particle size of indium tin oxide in the indium tin oxide paste is 10~50nm, and the solid content of the indium tin oxide paste is 20~40%.

6. The PVB film according to claim 1, characterized in that, Indole compounds include one or more of 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol, 2-2-hydroxy-5-benzylmethylbenzotriazole, 2-(2H-benzotriazol-2-yl)-4-methyl-6-(2-propenyl)phenol, and 2,4-di-tert-butyl-6-(5-chloro-2H-benzotriazol-2-yl)phenol.

7. The method for preparing PVB film according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Mix the components contained in the middle sound insulation, heat insulation and visual optimization layer to obtain the middle layer premix; S2. The components contained in the first PVB layer, the intermediate premix, and the components contained in the second PVB layer are co-extruded to obtain a PVB film.

8. The method for preparing PVB film according to claim 7, characterized in that, In S1, the mixing temperature is 85~95℃ and the mixing time is 15~25min.

9. The method for preparing PVB film according to claim 7, characterized in that, In S2, during the co-extrusion process, the barrel temperatures corresponding to the components contained in the first PVB layer and the components contained in the second PVB layer are 150~180℃, respectively, and the barrel temperature corresponding to the intermediate layer premix is ​​140~170℃.

10. The application of the PVB film according to any one of claims 1 to 6 or the PVB film prepared by the preparation method according to any one of claims 7 to 9 in laminated glass.