Multilayer composite functional PVB laminated glass intermediate film and preparation method thereof

Abstract

The invention relates to the technical field of laminated glass manufacturing, in particular to a multilayer composite functional PVB laminated glass intermediate film and a preparation method thereof. The sandwich structure of the outer layer A (hard layer), the middle layer (light diffusion functional layer) and the outer layer B (viscous layer) is creatively adopted, and the three core functions of light diffusion, high impact resistance and high adhesion are decoupled in the physical space and distributed to the three functional layers with independent structures and formulas. By means of the design, each layer can be subjected to optimized formula design according to the function target of the layer, and the fundamental contradiction that various properties cannot be collaboratively optimized in a single formula system is solved from the source. Through the structural innovation, the core safety performance of the middle film and the laminated glass can be greatly improved compared with that of a traditional single-layer light diffusion film while the excellent light diffusion effect is ensured.

Description

A multilayer composite functionalized PVB sandwich glass interlayer film and its preparation method Technical Field

[0001] This invention relates to the field of laminated glass manufacturing technology, and in particular to a multilayer composite functionalized PVB laminated glass interlayer film and its preparation method. Background Technology

[0002] Polyvinyl butyral (PVB) interlayer is a key material in the manufacture of safety laminated glass. It bonds two or more panes of glass together, preventing fragments from scattering and providing basic safety protection when the glass breaks. However, with the increasing demands for glass functionality in building curtain walls, automotive sunroofs, interior partitions, and display devices, the market demand for laminated glass has expanded beyond basic safety performance to include intelligent light control capabilities. For example, in some lighting structures, it is often necessary to convert direct, strong light into uniform, soft, diffused light to eliminate glare, protect privacy, and improve visual comfort.

[0003] Currently, to achieve the light diffusion function of laminated glass, the industry generally adopts the technical solution of incorporating inorganic light diffusion particles (such as titanium dioxide, zinc oxide, etc.) into a single-layer PVB interlayer. However, this method of achieving functional composite in a single homogeneous system has the following insurmountable technical defects: (1) Contradiction between mechanical properties and optical functions: As a rigid filler, the light diffusion particles have a significant modulus difference with the flexible PVB matrix. When subjected to impact, they are prone to become stress concentration points, inducing crack propagation, which leads to a decrease in the toughness, tear resistance and energy absorption capacity of the interlayer, thereby weakening the overall impact resistance and penetration resistance of the laminated glass. (2) Reduction in interfacial bonding reliability: In order to achieve an effective light diffusion effect, a certain amount of light diffusion particles need to be added to the PVB film. If these particles are distributed at the bonding interface between PVB and glass, they will physically hinder the polar hydroxyl groups in the PVB molecular chain from forming sufficient chemical bonds and hydrogen bond networks with the glass surface, resulting in a decrease in bonding strength, a deterioration in long-term weather resistance (such as resistance to damp heat aging), and a risk of delamination. (3) Limitations of formulation design and performance compromises: In a single PVB layer, high impact resistance requires high modulus and high glass transition temperature, which usually requires formulations with high degree of polymerization, high degree of acetalization and low plasticizer content; while high adhesion requires retaining more hydroxyl groups and using higher plasticizer content to improve adhesion and damping performance. These performance goals have inherent conflicts at the molecular structure level. The addition of light-diffusing particles further exacerbates the difficulty of formulation design, often resulting in products that are difficult to balance optical effects, mechanical strength and interfacial adhesion, and cannot achieve synergistic optimization of the three.

[0004] Therefore, existing light-diffusing PVB interlayers based on single-layer blending modification, due to the inherent limitations of their homogeneous structure, are unable to meet the stringent requirements for the overall performance of laminated glass in high-end applications. The industry urgently needs a novel interlayer structure design that can fundamentally overcome these performance bottlenecks. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the prior art by providing a multilayer composite functionalized PVB sandwich glass interlayer film and its preparation method. By designing a functional partition structure of "outer layer A (rigid layer), intermediate layer (light diffusion functional layer) and outer layer B (adhesive layer)," and combining it with co-extrusion and hot-pressing layer synthesis processes, light diffusion, high impact resistance, and high adhesion performance are decoupled in physical space and optimized separately. Ultimately, synergistic fusion is achieved at the interface molecular level, thereby overcoming the fundamental contradiction in existing single-layer blending modification technologies that are difficult to synergistically improve comprehensive performance.

[0006] To achieve the above objectives, the present invention provides a multilayer composite functionalized PVB interlayer glass interlayer, wherein the interlayer comprises, along its thickness direction, an outer layer A, an intermediate layer, and an outer layer B; the outer layer A comprises a first PVB resin and a first plasticizer; the first PVB resin has a viscosity-average degree of polymerization of 3000-4000 and an acetal degree of 68-80 mol%; the weight ratio of the first PVB resin to the first plasticizer is 100:(20-30); the intermediate layer comprises a second PVB resin, a second plasticizer, and light-diffusing particles; the absolute value of the refractive index difference between the light-diffusing particles and the intermediate layer matrix without the particles is ≥0.20; the outer layer B comprises a third PVB resin and a third plasticizer; the third PVB resin has an acetal degree of 60-68 mol%; the weight ratio of the third PVB resin to the third plasticizer is 100:(35-45).

[0007] Preferably, the haze value of the intermediate layer is ≤20%.

[0008] Preferably, the average particle size of the light-diffusing particles is 20-50 nm; the weight ratio of the second PVB resin to the light-diffusing particles is 100:(0.001-0.04).

[0009] Preferably, the light-diffusing particles are selected from at least one of titanium dioxide, zinc oxide, silicon dioxide, and organic polymer microspheres.

[0010] Preferably, the outer layer A further includes rigid nano-reinforcing particles; the rigid nano-reinforcing particles are selected from at least one of surface-treated nano-silica, surface-treated nano-alumina, and surface-treated nano-silicon carbide; the weight ratio of the first PVB resin to the rigid nano-reinforcing particles is 100:(0.5-3).

[0011] Preferably, the outer layer B further includes an adhesion modifier; the adhesion modifier is selected from at least one of magnesium acetate and potassium acetate; the weight ratio of the third PVB resin to the adhesion modifier is 100:(0.01-0.1).

[0012] Preferably, the first plasticizer is selected from triethylene glycol diisonononate, and the third plasticizer is selected from triethylene glycol di(2-ethylhexanoate).

[0013] The present invention also provides a method for preparing the multilayer composite functionalized PVB interlayer glass interlayer, comprising the following steps: S1. providing a mixture of outer layer A, interlayer and outer layer B respectively; S2. melting and plasticizing the three mixtures respectively, and co-extruding to form a three-layer composite melt sheet; S3. hot-pressing the three-layer composite melt sheet to obtain the multilayer composite functionalized PVB interlayer glass interlayer.

[0014] Preferably, in S3, the temperature of the hot-pressing lamination is 150-170℃ and the pressure is 5-15MPa.

[0015] The present invention also provides a laminated glass comprising at least two glass plates and the aforementioned multilayer composite functionalized PVB laminated glass interlayer film disposed between adjacent glass plates.

[0016] The beneficial effects of the present invention are as follows: (1) The present invention creatively adopts a sandwich structure of “outer layer A (hard layer), middle layer (light diffusion functional layer) and outer layer B (adhesive layer)”, which decouples the three core functions of light diffusion, high impact resistance and high adhesion in physical space and assigns them to three functional layers with independent structure and formulation. This design allows each layer to be optimally formulated according to its functional objectives, thus solving the fundamental contradiction that multiple properties cannot be synergistically optimized in a single formulation system.

[0017] (2) Thanks to the above-mentioned structural innovation, the interlayer film and laminated glass prepared by this invention can significantly improve the core safety performance compared with traditional single-layer light diffusion film while ensuring excellent light diffusion effect. Specifically, the high hardness design of the outer layer A can effectively disperse impact stress. Combined with the energy absorption mechanism of the three layers, the impact breakage height of the laminated glass is greatly increased. The high bonding formula of the outer layer B, combined with its high damping characteristics, ensures excellent and long-lasting bonding strength with the glass. Through the optimized hot-pressing fusion process, the three-layer interface forms a strong and tough bond mainly based on molecular chain entanglement. The interlayer peel strength is high, which ensures the integrity of the multilayer structure under stress.

[0018] (3) In this invention, the light-diffusing particles are completely encapsulated inside the interlayer, keeping them away from the bonding interface between the glass and the interlayer. This design fundamentally eliminates the physical barrier problem caused by the distribution of particles at the bonding interface in traditional methods, avoiding the resulting risks such as decreased bonding strength and deterioration in resistance to humid heat aging. Therefore, the laminated glass of this invention has better long-term environmental reliability and greatly reduces the safety risks caused by interface delamination.

[0019] (4) The core of the preparation method of this invention lies in "co-extrusion + hot pressing lamination" to achieve interfacial fusion. This process is based on mature plastic processing technology. Through optimized control of key parameters such as temperature and pressure, molecular-level fusion between the three layers can be achieved, and the process window is clear and stable. The entire process is efficient and continuous, highly compatible with the existing PVB film extrusion and laminated glass production industry chain, does not require complex or expensive special equipment, is easy to achieve large-scale stable production, and is conducive to the rapid promotion and application of the product. Detailed Implementation

[0020] This invention provides a multilayer composite functionalized PVB sandwich glass interlayer film, wherein the interlayer film comprises, along its thickness direction, an outer layer A, an intermediate layer, and an outer layer B. The outer layer A comprises a first PVB resin and a first plasticizer; the first PVB resin has a viscosity-average degree of polymerization (the average degree of polymerization measured by the viscometry method) of 3000-4000 and an acetal degree of 68-80 mol%; the weight ratio of the first PVB resin to the first plasticizer is 100:(20-30). The intermediate layer comprises a second PVB resin, a second plasticizer, and light-diffusing particles; the absolute value of the refractive index difference between the light-diffusing particles and the intermediate layer matrix without these particles is ≥0.20. The outer layer B comprises a third PVB resin and a third plasticizer; the third PVB resin has an acetal degree of 60-68 mol%, and the weight ratio of the third PVB resin to the third plasticizer is 100:(35-45).

[0021] In this invention, "intermediate layer matrix without the particles" refers to a homogeneous polymer system formed by mixing the second PVB resin and the second plasticizer in a specified ratio, which serves as a reference for calculating the refractive index difference with the light-diffusing particles.

[0022] In this invention, the interlayer film is arranged in the laminated glass in the following order: the side facing the external impact source or the outer glass plate is the outer layer A (rigid layer), followed by the intermediate layer (light diffusion functional layer) moving inwards, and the innermost side bonded to the inner glass plate is the outer layer B (adhesive layer). Through targeted formulation design and subsequent process control, a strong interfacial fusion can be achieved between the layers, thereby forming a synergistic whole.

[0023] In this invention, the outer layer A, as a rigid layer, directly faces external impact. Its core design is to maximize the rigidity of the material and the ability to disperse impact energy, which is achieved through the following collaborative design: (1) Resin structure design: A first PVB resin with high viscosity, average degree of polymerization (3000-4000), and high acetal content (68-80 mol%) is selected. This high molecular weight and low hydroxyl content give the resin intrinsic high modulus and low creep, laying a solid mechanical foundation for the outer layer A.

[0024] (2) Plasticizing system design: A low-addition plasticizer is used, with its weight ratio to the first PVB resin controlled within the range of 100:(20-30), for example, triethylene glycol diisonononate (3GIN). This design moderately improves the resin's processing fluidity while maximizing the rigidity of the polymer network, thereby increasing the glass transition temperature (Tg) of the material and ensuring that it exhibits a higher instantaneous modulus under impact loads, effectively resisting deformation.

[0025] (3) Functional Synergy and Interface Effect: Through the above formulation design, the outer layer A has high hardness characteristics, which can efficiently disperse stress in the initial stage of impact, inhibit crack initiation and rapid propagation, thereby providing a "protective shield" for the internal functional layers. In addition, this layer and the adjacent intermediate layer need to achieve a strong and tough bond through the mutual diffusion and entanglement of interface molecular chains in the subsequent hot pressing lamination process, so as to ensure the integrity and synergy of the multilayer structure under stress.

[0026] In this invention, the intermediate layer, as a light diffusion functional layer, is the core carrier for realizing optical functions. Its design needs to ensure excellent light diffusion effect while maintaining mechanical coherence with adjacent layers. Specifically, this is achieved through the following methods: (1) Resin matrix design: A second PVB resin with balanced performance is selected, whose degree of polymerization (usually 1400-2500) and acetal degree (usually 65-75 mol%) are between those of the resins of outer layer A and outer layer B. This design ensures good compatibility between the intermediate layer and adjacent layers, laying the foundation for the formation of a stable interface and stress transfer.

[0027] (2) Achievement of optical function: By introducing light-diffusing particles with an absolute value of refractive index difference ≥0.20 from the intermediate layer matrix and precisely controlling their addition amount, the haze value of the intermediate layer is ≤20%, thereby obtaining a soft and uniform light diffusion effect. The key is that these particles are completely encapsulated inside the intermediate layer, fundamentally avoiding direct contact between them and the outer glass, and eliminating the risk of reduced bonding strength due to the presence of particles at the bonding interface.

[0028] (3) Mechanical synergy: The intermediate layer, located between the inner and outer layers, is protected by both outer layer A and outer layer B. The light-diffusing particles inside it will not become a weak point in the overall structure. At the same time, the relatively soft resin matrix of this layer can effectively transfer and dissipate the impact energy dispersed from outer layer A, achieving a smooth transition and synergy of mechanical properties.

[0029] In this invention, the outer layer B serves as an adhesive layer directly bonded to the inner glass plate. Its design aims to achieve the ultimate and durable interfacial adhesion while possessing excellent viscoelastic damping characteristics. Specifically, this is achieved through the following synergistic design: (1) Resin structure design: A third PVB resin with a low acetal content (60-68 mol%) is used. This structure retains more hydroxyl groups (-OH), providing a chemical basis for forming strong hydrogen bonds with the glass surface, which is the key to achieving high bonding strength.

[0030] (2) Plasticizing system design: A high content of plasticizer is used, with a weight ratio of 100:(35-45) to the third PVB resin, for example, triethylene glycol di(2-ethylhexanoate) (3GO). The high plasticizer content significantly enhances the mobility of the resin chain segments and lowers the glass transition temperature (Tg). This not only improves the adhesion of the interlayer at room temperature, making it easier to adhere to the glass surface, but also endows the layer with outstanding viscoelastic damping properties, which can efficiently absorb and dissipate energy from impact and vibration.

[0031] (3) Functional Synergy and Overall Effect: The strong interfacial adhesion ensures that the glass and the interlayer form a complete whole, allowing impact energy to be effectively transferred from the glass to the entire interlayer system. At the same time, the high damping characteristics of this layer and the high rigidity of the outer layer A form a mechanical complement, jointly constructing a broadband energy absorption and dissipation mechanism, thereby significantly improving the overall safety performance of the laminated glass.

[0032] In this invention, the haze value of the intermediate layer is ≤20%.

[0033] In this invention, the average particle size of the light-diffusing particles is 20-50 nm; the weight ratio of the second PVB resin to the light-diffusing particles is 100:(0.001-0.04).

[0034] In this invention, the light-diffusing particles are selected from at least one of titanium dioxide, zinc oxide, silicon dioxide, and organic polymer microspheres, and more preferably titanium dioxide.

[0035] Nanoscale light-diffusing particles can efficiently scatter visible light, thereby effectively suppressing specular reflection and glare on glass surfaces. This property can effectively eliminate light pollution caused by glass reflection and create a uniform and soft diffuse reflection effect, thus improving visual comfort.

[0036] In this invention, the organic polymer microspheres may be selected from polymethyl methacrylate (PMMA) microspheres, polystyrene (PS) microspheres, styrene-acrylate copolymer microspheres, cross-linked polyacrylate microspheres, or silicone resin microspheres; their refractive index must meet the aforementioned refractive index difference requirement with the intermediate layer matrix (second PVB resin + second plasticizer), and their glass transition temperature or thermal decomposition temperature should be higher than the processing temperature of the intermediate film to ensure the stability of the spherical structure and optical properties during processing.

[0037] In this invention, the outer layer A further includes rigid nano-reinforcing particles; the rigid nano-reinforcing particles are selected from at least one of surface-treated nano-silica, surface-treated nano-alumina, and surface-treated nano-silicon carbide; the weight ratio of the first PVB resin to the rigid nano-reinforcing particles is 100:(0.5-3).

[0038] In this invention, the surface treatment is not limited to a specific type and can be performed using at least one of silane coupling agents, titanate coupling agents, or aluminate coupling agents, with the aim of improving the dispersion of particles in the matrix and the interfacial bonding force.

[0039] In this invention, the outer layer B further includes an adhesion modifier; the adhesion modifier is selected from at least one of magnesium acetate and potassium acetate; the weight ratio of the third PVB resin to the adhesion modifier is 100:(0.01-0.1).

[0040] In this invention, the first plasticizer is selected from triethylene glycol diisonononate (3GIN), and the third plasticizer is selected from triethylene glycol di(2-ethylhexanoate) (3GO).

[0041] This invention also provides a method for preparing the multilayer composite functionalized PVB interlayer glass interlayer film. The core of this method lies in achieving high-strength interfacial fusion between the three layers through a specific process, rather than conventional physical lamination. Specifically, it includes the following steps: S1. Providing mixtures of outer layer A, interlayer, and outer layer B respectively; S2. Melting and plasticizing the three mixtures separately, and co-extruding them to form a three-layer composite melt sheet; S3. Hot-pressing the three-layer composite melt sheet to obtain the multilayer composite functionalized PVB interlayer glass interlayer film.

[0042] In this invention, during step S3, the temperature for hot-pressing lamination is 150-170°C, and the pressure is 5-15 MPa. This range of process parameters is crucial for ensuring the success of multilayer lamination. Its core lies in precisely controlling the temperature and pressure to promote sufficient molecular chain diffusion and entanglement at the interface of PVB layers with different formulations, achieving true "fusion" rather than simple physical bonding.

[0043] Temperature Control (150-170℃): This temperature range is set above the glass transition temperature of each PVB resin layer, while being below its rapid thermal degradation temperature. Under these conditions, PVB molecular chains have sufficient mobility to diffuse and entangle across the interlayer interfaces. Too low a temperature leads to insufficient molecular chain diffusion and weakened interfacial bonding; too high a temperature may cause plasticizer volatilization or resin degradation. Pressure Control (5-15MPa): Applying sufficient pressure is crucial to ensuring tight contact between layers, eliminating microbubbles at the interfaces, and providing the physical driving force for molecular chain segments to penetrate the interfaces. Uniform and stable pressure helps avoid internal stress or uneven thickness, thus ensuring lamination quality. Synergistic Effect: Within this optimized process window, a gradient interface dominated by the physical entanglement structure of molecular chains is formed between the three layers, with a bonding strength far exceeding that of adhesive-based bonding interfaces. This not only ensures the integrity of the multilayer structure during long-term use and harsh environments but also allows the three layers to truly function as a cohesive whole, a core element in achieving the non-separation and synergistic effect of the three-layer structure during service.

[0044] In this invention, in step S3, after hot pressing and lamination, the resulting film is sequentially cooled, trimmed, and rolled up to obtain a multilayer composite functionalized PVB interlayer glass interlayer film.

[0045] The present invention also provides a laminated glass comprising at least two glass plates and the aforementioned multilayer composite functionalized PVB laminated glass interlayer film disposed between adjacent glass plates.

[0046] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0047] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0048] In the following embodiments and comparative examples of the present invention, "parts" refers to "parts by weight".

[0049] Example 1 This example provides a method for preparing a multilayer composite functionalized PVB interlayer glass interlayer (total thickness 0.76 mm, with equal thickness of each layer), including the following steps: Outer layer A: Take 100 parts of PVB resin with an average viscosity of 3500 and an acetal degree of 75 mol%, add 25 parts of plasticizer (3GIN), and 1 part of nano-silica treated with γ-aminopropyltriethoxysilane (KH-550). (The preparation process of nano-silica treated with KH-550 includes: dispersing nano-silica in a mixed solvent of ethanol and water.) A dispersion was formed in a mixture of ethanol and water at a volume ratio of 9:1. KH-550 was added to this dispersion, and the pH of the system was adjusted to 4.5 with acetic acid. The mixture was stirred at 65°C for 3 hours. After the reaction was completed, the nano-silica treated with KH-550 was obtained by centrifugation, washing, and drying. The nano-silica, mixed solvent, and KH-550 were mixed in a mass-to-volume ratio of 1 g:100 mL:0.02 g, along with 0.5 parts of stabilizer (0.25 parts of antioxidant 1076 + 0.25 parts of UV absorber UV-328), and were thoroughly mixed.

[0050] Intermediate layer: Take 100 parts of PVB resin with an average viscosity of 2000 and an acetal degree of 70 mol%, add 35 parts of plasticizer (20 parts 3GIN + 15 parts 3GO), 0.015 parts of light-diffusing particles (rutile titanium dioxide with an average particle size of 35 nm), and 0.5 parts of stabilizer (0.25 parts antioxidant 1076 + 0.25 parts ultraviolet absorber UV-328), and mix thoroughly. The absolute value of the refractive index difference between the light-diffusing particles and the intermediate layer matrix without these particles is 1.22, and the haze value of the intermediate layer is 18.5%.

[0051] Outer layer B: Take 100 parts of PVB resin with an average viscosity of 1700 and an acetal degree of 65 mol%, add 40 parts of plasticizer (3GO), 0.05 parts of adhesion modifier (0.025 parts magnesium acetate + 0.025 parts potassium acetate) and 0.5 parts of stabilizer (0.25 parts antioxidant 1076 + 0.25 parts ultraviolet absorber UV-328), and mix evenly.

[0052] Preparation and Lamination: The mixtures of the three formulations were melt-plasticized separately in a twin-screw extruder, and then co-extruded through a three-layer co-extrusion die to form a three-layer composite melt sheet. This sheet was then immediately fed into a hot press roller device and hot-pressed at 160℃ and 10MPa for 5 minutes to ensure full fusion of the interlayer interfaces. Finally, after cooling, edge trimming, and winding, a multilayer composite functionalized PVB interlayer glass interlayer with a total thickness of 0.76mm was obtained.

[0053] Example 2 This example provides a method for preparing a multilayer composite functionalized PVB interlayer glass interlayer film (total thickness 0.76 mm, each layer has equal thickness), which differs from Example 1 in that: (1) In the outer layer A, the amount of nano-silica treated with KH-550 is adjusted to 2 parts, and the amount of plasticizer (3GIN) is adjusted to 28 parts.

[0054] (2) In the intermediate layer, the number of light-diffusing particles is adjusted to 0.01 parts; the haze value of the intermediate layer is 12.0%.

[0055] (3) In the outer layer B, the amount of adhesion regulator is adjusted to 0.08 parts (0.04 parts magnesium acetate + 0.04 parts potassium acetate).

[0056] Example 3 This example provides a method for preparing a multilayer composite functionalized PVB interlayer glass intermediate film (total thickness 0.76 mm, each layer has equal thickness), which differs from Example 1 in that: (1) In the outer layer A, the amount of nano-silica treated with KH-550 is adjusted to 1.5 parts.

[0057] (2) In the intermediate layer, the proportion of light-diffusing particles is adjusted to 0.02 parts, and the type of light-diffusing particles is adjusted to polymethyl methacrylate microspheres with an average particle size of 3.0 μm. The absolute value of the refractive index difference between the light-diffusing particles and the intermediate layer matrix without these particles is 0.21, and the haze value of the intermediate layer is 15.5%.

[0058] (3) In the outer layer B, the amount of adhesion regulator is adjusted to 0.05 parts (the weight ratio of magnesium acetate to potassium acetate is 2:1).

[0059] Comparative Example 1: This comparative example provides a method for preparing a PVB interlayer (0.76 mm thick), comprising the following steps: 100 parts of PVB resin with an average viscosity of 2000 and an acetal degree of 70 mol%, are taken, and 35 parts of plasticizer (20 parts of 3GIN + 15 parts of 3GO), 0.015 parts of light-diffusing particles (rutile titanium dioxide with an average particle size of 35 nm), 0.05 parts (0.025 parts of magnesium acetate + 0.025 parts of potassium acetate), and 0.5 parts of stabilizer (0.25 parts of antioxidant 1076 + 0.25 parts of ultraviolet absorber UV-328) are added and mixed evenly. The mixture is melted and plasticized at 160°C, extruded through a single-layer extrusion die under a pressure of 8 MPa, cooled and shaped by a casting roller at 22°C, and finally wound up to obtain a PVB interlayer with a thickness of 0.76 mm.

[0060] Comparative Example 2 provides a method for preparing a PVB interlayer glass (total thickness 0.76 mm, with each layer having equal thickness), which differs from Example 1 in that the interlayer is omitted.

[0061] In Experiment 1, the intermediate films obtained in Examples 1-3 and Comparative Examples 1-2 were respectively made into laminated glass samples, and their performance was compared and tested.

[0062] (1) Sample preparation: Take two clean float glass plates with a size of 300mm×300mm×3mm, place the cut intermediate film in the middle, and perform pre-compression treatment (in a vacuum bag, under the conditions of 98kPa and 95℃ for 13min) and final compression treatment (placed in an autoclave, under the conditions of 135℃ and 1.2MPa for 30min). After the treatment is completed, cool to obtain the laminated glass sample.

[0063] (2) Test methods and standards: Haze: According to GB / T 2410-2008, the laminated glass samples were tested using a haze meter, and the results were expressed as a percentage.

[0064] Pummel adhesion rating: According to industry-standard methods, the sample is frozen at -18°C and then struck, and rated based on the area of ​​glass fragments remaining (0-10).

[0065] Drop ball impact breakage height: According to GB / T 9962-2022, a drop ball impact test was conducted using a steel ball with a mass of 2.26 kg, and the maximum drop height from which the sample was not penetrated was recorded.

[0066] Interlayer peel strength: According to GB / T 2790-1995, a 180° peel test was performed at a rate of 100 mm / min, and the results are expressed in N / cm.

[0067] The test results are recorded in Table 1.

[0068] Table 1 Test Results

[0069] As shown in Table 1, the three-layer composite structure of this invention (Examples 1, 2, and 3) successfully overcomes the performance bottleneck of the single-layer blended modified film (Comparative Example 1), significantly improving the core safety performance of laminated glass—impact resistance and interfacial bonding reliability—while ensuring effective light diffusion. Meanwhile, Comparative Example 2 demonstrates that optical performance cannot be achieved without a dedicated intermediate layer, and its two-layer structure is inferior to the three-layer composite structure of this invention in terms of mechanical synergy. This invention, through structural innovation and process optimization, provides an effective technical path for achieving high-performance light-diffusing laminated glass.

[0070] Therefore, this invention employs the aforementioned multilayer composite functionalized PVB interlayer glass interlayer and its preparation method. By designing a functional partition structure of "outer layer A (rigid layer), intermediate layer (light diffusion functional layer), and outer layer B (adhesive layer)," and combining it with co-extrusion and hot-pressing layer synthesis processes, light diffusion, high impact resistance, and high adhesion properties are decoupled in physical space and optimized separately. Ultimately, synergistic fusion is achieved at the interface molecular level, thereby overcoming the fundamental contradiction in existing single-layer blending modification technologies that make it difficult to synergistically improve comprehensive performance.

[0071] Finally, it should be noted that the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A multilayer composite functionalized PVB interlayer glass interlayer, characterized in that, The intermediate film comprises, along its thickness direction, an outer layer A, an intermediate layer, and an outer layer B. The outer layer A comprises a first PVB resin and a first plasticizer. The first PVB resin has a viscosity-average degree of polymerization of 3000-4000 and an acetal degree of 68-80 mol%. The weight ratio of the first PVB resin to the first plasticizer is 100:(20-30). The intermediate layer comprises a second PVB resin, a second plasticizer, and light-diffusing particles. The absolute value of the refractive index difference between the light-diffusing particles and the intermediate layer matrix without these particles is ≥0.

20. The outer layer B comprises a third PVB resin and a third plasticizer. The third PVB resin has an acetal degree of 60-68 mol%, and the weight ratio of the third PVB resin to the third plasticizer is 100:(35-45).

2. The multilayer composite functionalized PVB interlayer glass interlayer according to claim 1, characterized in that, The haze value of the intermediate layer is ≤20%.

3. The multilayer composite functionalized PVB interlayer glass interlayer according to claim 1, characterized in that, The average particle size of the light-diffusing particles is 20-50 nm; the weight ratio of the second PVB resin to the light-diffusing particles is 100:(0.001-0.04).

4. The multilayer composite functionalized PVB interlayer glass interlayer according to claim 1 or 3, characterized in that, The light-diffusing particles are selected from at least one of titanium dioxide, zinc oxide, silicon dioxide, and organic polymer microspheres.

5. The multilayer composite functionalized PVB interlayer glass interlayer film according to claim 1, characterized in that, The outer layer A also includes rigid nano-reinforcing particles; the rigid nano-reinforcing particles are selected from at least one of surface-treated nano-silica, surface-treated nano-alumina, and surface-treated nano-silicon carbide; the weight ratio of the first PVB resin to the rigid nano-reinforcing particles is 100:(0.5-3).

6. The multilayer composite functionalized PVB interlayer glass interlayer according to claim 1, characterized in that, The outer layer B also includes an adhesion modifier; the adhesion modifier is selected from at least one of magnesium acetate and potassium acetate; the weight ratio of the third PVB resin to the adhesion modifier is 100:(0.01-0.1).

7. The multilayer composite functionalized PVB interlayer glass interlayer according to claim 1, characterized in that, The first plasticizer is selected from triethylene glycol diisonononate, and the third plasticizer is selected from triethylene glycol di(2-ethylhexanoate).

8. A method for preparing a multilayer composite functionalized PVB interlayer glass interlayer as described in any one of claims 1 to 7, characterized in that, Includes the following steps: S1. Provide mixtures of outer layer A, intermediate layer and outer layer B respectively; S2. Melt and plasticize the three mixtures respectively, and co-extrude them to form a three-layer composite melt sheet; S3. Hot-press the three-layer composite melt sheet to obtain the multi-layer composite functionalized PVB interlayer glass interlayer film.

9. The preparation method according to claim 8, characterized in that, In S3, the temperature of the hot-pressed lamination is 150-170℃ and the pressure is 5-15MPa.

10. A laminated glass, characterized in that, It includes at least two glass plates and a multilayer composite functionalized PVB interlayer glass interlayer film as described in any one of claims 1 to 7, placed between adjacent glass plates.

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