A binary composite plasticized gradient structure PVB interlayer film and its preparation method, and laminated glass

Abstract

This invention relates to the field of interlayer technology in laminated glass, and particularly to a binary composite plasticized gradient structure PVB interlayer, its preparation method, and laminated glass. The interlayer has a three-layer gradient structure, consisting of a first surface layer, a middle sound-insulating layer, and a second surface layer from the outside in. Both the first and second surface layers contain a first PVB resin and a first composite plasticizer, which includes diethylene glycol dibenzoate and 3GO. The middle sound-insulating layer contains a second PVB resin and a second composite plasticizer, which includes a mixture of diethylene glycol dibenzoate and 3GH. This invention, through innovative material formulation and structural design, provides a PVB interlayer solution that balances high weather resistance, excellent sound insulation, strong adhesion, low plasticizer migration tendency, and additional heat insulation functions. It also includes a stable and efficient preparation method, effectively overcoming the limitations of existing technologies where performance cannot be synergistically improved.

Description

Technical Field

[0001] This invention relates to the field of interlayer film technology in laminated glass, and in particular to a binary compound plasticized gradient structure PVB interlayer film, its preparation method, and laminated glass. Background Technology

[0002] Laminated glass, as an important safety material, is widely used in the automotive and construction industries, and its performance mainly depends on the polyvinyl butyral (PVB) interlayer. The key to optimizing the performance of PVB interlayers lies in the design of the plasticizing system. Currently, commonly used PVB interlayer plasticizing systems mainly employ single ester plasticizers, such as triethylene glycol di-2-ethylhexanoate (3GO) or triethylene glycol di-2-ethylbutyrate (3GH). While these plasticizers can meet the basic flexibility requirements of the interlayer to some extent, they still have the following significant drawbacks in practical applications: First, single plasticizers are difficult to adapt to the differentiated performance requirements of each layer in a gradient structure interlayer. A gradient structure typically includes a surface layer and an interlayer. The surface layer requires high dimensional stability and anti-aging properties to suppress the formation of end voids, while the interlayer needs excellent damping characteristics to achieve efficient sound insulation. Single ester plasticizers cannot simultaneously address both of these properties, preventing the full realization of the design advantages of the gradient structure. Secondly, during long-term use, traditional ester plasticizers are prone to migration and volatilization, which leads to the gradual embrittlement of the interlayer and a decrease in adhesion, affecting the long-term safety and service life of laminated glass.

[0003] While existing technologies have attempted to improve performance by adjusting plasticizer content or through simple compounding, no dedicated compounding system has been developed to specifically match the functional requirements of each layer in a gradient structure. Furthermore, traditional preparation processes have not been optimized for compounded plasticizer systems, easily leading to uneven dispersion of the plasticizer in PVB resin, affecting the performance consistency and stability of the final product. Therefore, existing technologies still lack a plasticizer system and corresponding preparation method that can truly adapt to gradient structure PVB interlayer films, possessing high stability, high sound insulation, strong adhesion, and long-term aging resistance. Summary of the Invention

[0004] The purpose of this invention is to address the problems existing in the prior art by providing a binary compound plasticized gradient structure PVB interlayer film, its preparation method, and laminated glass. Through innovative material formulation and structural design, this invention provides a PVB interlayer film solution that can balance high weather resistance, excellent sound insulation, strong adhesion, low plasticizer migration tendency, and additional heat insulation function.

[0005] To achieve the above objectives, the present invention provides a binary compound plasticized gradient structure PVB interlayer film, wherein the interlayer film has a three-layer gradient structure, consisting of a first surface layer, a middle sound insulation layer, and a second surface layer from the outside to the inside. Both the first surface layer and the second surface layer contain a first PVB resin and a first compound plasticizer, wherein the first compound plasticizer includes diethylene glycol dibenzoate and 3GO; The intermediate sound insulation layer comprises a second PVB resin and a second compound plasticizer, wherein the second compound plasticizer comprises a mixture of dibenzoyl diol esters and 3GH; the mixture of dibenzoyl diol esters comprises dipropylene glycol dibenzoate, diethylene glycol dibenzoate and propylene glycol dibenzoate.

[0006] 3GO is triethylene glycol di-2-ethylhexanoate, CAS number 94-28-0; 3GH is triethylene glycol di-2-ethylbutyrate, CAS number 105-72-6; propylene glycol dibenzoate, CAS number 19224-26-1.

[0007] In an optional embodiment, the diol dibenzoate mixture comprises dipropylene glycol dibenzoate, diethylene glycol dibenzoate and propylene glycol dibenzoate in a mass ratio of (75~85):(10~20):(3~7).

[0008] In an optional embodiment, in the first compound plasticizer, the mass ratio of diethylene glycol dibenzoate to 3GO is 1:(2~3); and the mass ratio of the first PVB resin to the first compound plasticizer is 100:(25~32).

[0009] In an optional embodiment, in the second compound plasticizer, the mass ratio of the dibenzoyl diol mixture to 3GH is 1:(1~2); the mass ratio of the second PVB resin to the second compound plasticizer is 100:(60~75).

[0010] In an optional embodiment, the first PVB resin has a weight-average molecular weight of 180,000 to 220,000, a hydroxyl content of 10 to 26 mol%, a degree of acetylation of 0.5 to 12 mol%, and a degree of acetalization of 65 to 75 mol.

[0011] In an optional embodiment, the second PVB resin has a weight-average molecular weight of 65,000 to 85,000, a hydroxyl content of 12 to 25 mol%, a degree of acetylation of 7 to 12 mol%, and a degree of acetalization of 68 to 75 mol%.

[0012] In an optional embodiment, the first surface layer and the second surface layer further comprise an ultraviolet shielding agent, an antioxidant, and a metal salt, respectively; the ultraviolet shielding agent is selected from 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole; the antioxidant includes 2,6-di-tert-butyl-p-cresol and tris(2,4-di-tert-butylphenyl) phosphite, with a mass ratio of 2,6-di-tert-butyl-p-cresol to tris(2,4-di-tert-butylphenyl) phosphite of (1.5~2.5):1; the metal salt includes magnesium acetate and potassium 2-ethylhexanoate, with a mass ratio of magnesium acetate to potassium 2-ethylhexanoate of 1:(1.5~2.5).

[0013] In an optional embodiment, the mass fractions of the ultraviolet shielding agent in the first surface layer and the second surface layer are 0.3-0.6%, the mass fractions of the antioxidant are 0.1-0.3%, and the content of the metal salt is 40-80 ppm.

[0014] In an optional embodiment, the intermediate sound insulation layer further comprises heat-insulating particles; the heat-insulating particles are selected from cesium-doped tungsten oxide (CsO2). 0.33 WO3); the average particle size of the heat-insulating particles is 0.02~0.05μm.

[0015] In one optional implementation, the mass fraction of heat-insulating particles in the intermediate sound insulation layer is 1.5 to 3%.

[0016] In one optional embodiment, the thickness ratio of the first surface layer, the intermediate sound insulation layer, and the second surface layer is (35~45):(10~30):(35~45); the total thickness of the intermediate film is 0.6~1.5mm.

[0017] The present invention also provides a method for preparing the aforementioned binary composite plasticized gradient structure PVB interlayer film, comprising the following steps: S1. Prepare the first surface layer premix, the middle sound insulation layer premix, and the second surface layer premix respectively; S2. The first surface layer premix, the middle sound insulation layer premix, and the second surface layer premix are melt-extruded separately and co-extruded to form a gradient structure melt film; S3. The gradient structure molten film is sequentially subjected to casting, cooling, and curing treatments to obtain the binary compound plasticized gradient structure PVB intermediate film.

[0018] In an optional implementation, S1 specifically includes the following steps: (1) Raw material pretreatment The first PVB resin and the second PVB resin were dried at a temperature of 80~90℃ and a vacuum degree of -0.08~-0.09MPa for 4~6 hours to remove the moisture contained in the resin.

[0019] Diethylene glycol dibenzoate and 3GO were mixed at a mass ratio of 1:(2~12) and stirred for 15~20 min at a temperature of 60~70℃ and a rotation speed of 300~500 r / min until homogeneous, to obtain the first compound plasticizer. The mixture of diethylene glycol dibenzoate and 3GH were mixed at a mass ratio of 1:(1~2) and stirred for 15~20 min at a temperature of 60~70℃ and a rotation speed of 300~500 r / min until homogeneous, to obtain the second compound plasticizer.

[0020] Add the heat-insulating particles to 3GH (the mass ratio of heat-insulating particles to 3GH is 1: (5~15)) and disperse them at high speed for 30~40 min at a temperature of 60~70℃ and a rotation speed of 2000~3000 r / min. After dispersion, grind the particles until the particle size is ≤0.05μm to obtain the heat-insulating particle dispersion.

[0021] (2) Preparation of premixes for each layer Preparation of the first / second surface layer premix: The first PVB resin, the first compound plasticizer and other additives (ultraviolet shielding agent, antioxidant and metal salt) are mixed for 30 to 40 minutes at a temperature of 80 to 90°C and a rotation speed of 500 to 800 r / min to obtain the first surface layer premix and the second surface layer premix.

[0022] Preparation of intermediate sound insulation layer premix: The second PVB resin and the second compound plasticizer are mixed at a temperature of 75~85℃ and a rotation speed of 600~900r / min for 20~30min. Then, the heat insulation particle dispersion is added and the mixture is mixed for another 15~20min to obtain the intermediate sound insulation layer premix.

[0023] In an optional embodiment, in S2, the melt extrusion temperatures of the first surface layer premix and the second surface layer premix are 160~180℃, respectively; and the melt extrusion temperature of the intermediate sound insulation layer premix is ​​150~170℃.

[0024] In an optional embodiment, in S2, after melt extrusion, the material is filtered through a 150-250 mesh metal filter to remove impurities and unmelted particles. Then, the filtered molten material is conveyed to a three-layer co-extrusion die. At a die temperature of 170-185°C, the first surface layer, the middle sound insulation layer, and the second surface layer are sequentially composited and tightly bonded through the precise distribution of the flow channels inside the die, forming a gradient structure melt film with good interface fusion and stable structure.

[0025] In an optional embodiment, in step S3, the gradient-structured molten film is cast onto a three-section cooling roller assembly for gradient cooling and shaping. The temperatures of each cooling roller section are controlled sequentially as follows: first section 80-90°C, second section 50-60°C, and third section 25-35°C; the film traction speed is controlled at 1.5-3 m / min. Through the combination of gradient cooling and uniform traction, the film material is cooled and shaped slowly and uniformly.

[0026] In an optional embodiment, in S3, the cooled and shaped membrane material undergoes the following post-processing steps in sequence: (1) Thickness measurement and trimming: The membrane material is continuously measured using an online laser thickness gauge with a thickness measurement accuracy of ±0.005mm. Based on the thickness measurement results, the membrane material is trimmed on both sides using an edge trimming machine to control its width to 1.2~1.5m and the edge straightness error to ≤0.5mm / m, so as to ensure that the membrane material size is consistent. (2) Embossing treatment: The trimmed film material is fed into the embossing roller and embossed under the conditions of 40~50℃ and 0.3~0.5MPa to form a uniform embossed pattern with a pattern depth of 5~10μm to enhance the adhesion between the film material and the glass. (3) Traction and winding: The traction tension is controlled at 50~80N by the tension controller so that the embossed film is wound onto the paper core. The winding speed is synchronized with the traction speed. During the winding process, the edge control system is used to ensure that the winding alignment error is ≤1mm.

[0027] In an optional embodiment, in S3, the curing treatment is carried out at a temperature of 20-25°C, a relative humidity of 25-35%, and a time of 66-78 hours.

[0028] The present invention also provides a laminated glass comprising two glass substrates disposed opposite each other, and a binary composite plasticized gradient structure PVB interlayer sandwiched between the two glass substrates.

[0029] In an optional embodiment, the method for preparing the laminated glass includes the following steps: The first glass substrate, the intermediate film, and the second glass substrate are sequentially stacked and placed in a vacuum laminator. They are pre-pressed for 30-40 minutes at a temperature of 90-100°C and a vacuum degree of -0.09 to -0.095 MPa to fully expel interlayer air. The pre-pressed composite is then transferred to an autoclave and subjected to high-temperature and high-pressure pressing at 120-140°C and 1.2-1.5 MPa for 60-90 minutes to form a strong and dense bond between the intermediate film and the glass substrate, thereby obtaining the laminated glass.

[0030] This invention provides a binary composite plasticized gradient structure PVB interlayer film, its preparation method, and laminated glass. By constructing a specific three-layer gradient structure and a matching exclusive composite plasticizing system, the following beneficial effects are achieved: (1) The plasticizing network structure of PVB resin was optimized by using a compound plasticizing system of diethylene glycol dibenzoate and 3GO in the first and second surface layers. This system not only imparts suitable flexibility to the surface layer, but also significantly improves its dimensional stability and creep resistance, thereby effectively suppressing end voids caused by film shrinkage under long-term environmental stresses such as light, heat, and humidity, and greatly improving the long-term weather resistance and appearance reliability of laminated glass.

[0031] (2) By using a compound plasticizing system of dibenzoyl diol esters and 3GH in the intermediate sound insulation layer, the damping loss factor of the layer is significantly improved by utilizing the high internal friction characteristics of the dibenzoyl diol esters. This design effectively enhances the absorption and dissipation capacity of the intermediate layer for sound wave vibration energy, thereby enabling the laminated glass to exhibit excellent sound insulation performance in the mid-to-low frequency range (such as 315Hz).

[0032] (3) The diethylene glycol dibenzoate / 3GO compound plasticizer system used in the surface layer, in synergy with the metal salt additives, optimizes the polarity distribution and interfacial characteristics of the PVB resin, thereby significantly improving the initial bonding strength between the interlayer and the glass substrate. In addition, the selected plasticizers, such as diethylene glycol dibenzoate and diethylene glycol dibenzoate mixtures, have a low migration tendency due to their large molecular structure and excellent compatibility with PVB resin. Combined with the gradient structure design (low plasticizer content in the surface layer), the migration and volatilization of plasticizers during long-term use are inhibited from both the formulation and structure perspectives, effectively maintaining the flexibility and long-term bonding reliability of the interlayer.

[0033] (4) This invention creatively combines a highly stable surface layer (matched with high weight-average molecular weight PVB resin and diethylene glycol dibenzoate / 3GO system) with a highly damping intermediate layer (matched with low weight-average molecular weight PVB resin, diethylene glycol dibenzoate mixture / 3GH system and functional heat-insulating particles) in an optimized thickness ratio. This integrated design of "gradient structure - exclusive compound - functional filler" enables a single intermediate membrane to simultaneously possess multiple properties such as anti-aging, high sound insulation, strong adhesion, low migration and high-efficiency infrared heat insulation, solving the technical contradiction that it is difficult to achieve all the properties in traditional technologies.

[0034] (5) The raw material pretreatment and premixing processes designed for this compound plasticizing system ensure the uniform dispersion and fusion of each component (especially various plasticizers, PVB resin, and functional fillers). Optimized layered melt extrusion temperature, three-stage gradient cooling process, and precise online thickness measurement, embossing, and winding post-processing steps effectively control the rheological matching of each melt layer, the interlayer interface fusion quality, and the dimensional accuracy and internal stress distribution of the final film. The entire preparation method is stable and controllable, suitable for continuous industrial production, and can guarantee a high degree of consistency and repeatability of product performance.

[0035] In summary, this invention provides a PVB interlayer solution that combines high weather resistance, excellent sound insulation, strong adhesion, low plasticizer migration tendency, and additional heat insulation function through innovative material formulation and structural design. It also includes a stable and efficient preparation method, which effectively overcomes the limitations of existing technologies in synergistic performance improvement. Detailed Implementation

[0036] 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.

[0037] 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.

[0038] In the following embodiments and comparative examples of the present invention, the dibenzoyl diol mixture includes dipropylene glycol dibenzoate, diethylene glycol dibenzoate and propylene glycol dibenzoate, with a mass ratio of 80:15:5.

[0039] Example 1 This embodiment provides a binary compound plasticized gradient structure PVB interlayer film.

[0040] (1) Structural design: The intermediate membrane is a three-layer gradient structure with a total thickness of 0.8 mm. The thickness of the first surface layer and the second surface layer is 0.32 mm, and the thickness of the middle sound insulation layer is 0.16 mm.

[0041] (2) Raw material composition The first and second surface layers (with identical compositions) consist of: 100 parts by weight of a first PVB resin (weight-average molecular weight 200,000, hydroxyl content 22 mol%, degree of acetylation 1 mol%, degree of acetalization 68 mol%); 28 parts by weight of a first compound plasticizer (diethylene glycol dibenzoate and 3GO, mass ratio 1:2.5); a UV shielding agent (2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole); an antioxidant (2,6-di-tert-butyl-p-cresol and tris(2,4-di-tert-butylphenyl) phosphite, mass ratio 2:1); and a metal salt (magnesium acetate and potassium 2-ethylhexanoate, mass ratio 1:2). The surface layer contains 0.4% UV shielding agent, 0.2% antioxidant, and 50 ppm metal salt.

[0042] Intermediate sound insulation layer: 100 parts by weight of second PVB resin (weight average molecular weight 75,000, hydroxyl content 18 mol%, acetylation degree 9 mol%, acetalization degree 70 mol%); 68 parts by weight of second compound plasticizer (a mixture of dibenzoyl diol esters and 3GH, in a mass ratio of 1:1.5); heat insulation particles (Cs 0.33 WO3 (with an average particle size of 0.03 μm). The heat-insulating particles in the middle sound-insulating layer comprise 2% of the total mass.

[0043] (3) Preparation Raw material pretreatment: The first and second PVB resins were dried at 85℃ and -0.085MPa for 5 hours. Diethylene glycol dibenzoate and 3GO were stirred at 65℃ and 400 rpm for 17 minutes to obtain the first compound plasticizer. A mixture of diethylene glycol dibenzoate and 3GH was stirred at 65℃ and 400 rpm for 17 minutes to obtain the second compound plasticizer. Insulating particles were added to 3GH (mass ratio of insulating particles to 3GH: 1:12) and dispersed at 65℃ and 2500 rpm for 35 minutes. After dispersion, the particles were ground to a particle size ≤0.05μm to obtain an insulating particle dispersion.

[0044] Preparation of premixes for each layer: The first PVB resin, the first compound plasticizer, and other additives (UV shielding agent, antioxidant, and metal salt) were mixed at 85°C and 650 r / min for 35 min to obtain the first surface layer premix and the second surface layer premix. The second PVB resin and the second compound plasticizer were mixed at 80°C and 750 r / min for 25 min, and then the heat insulation particle dispersion was added and the mixture was mixed for another 17 min to obtain the intermediate sound insulation layer premix.

[0045] Melt extrusion, co-extrusion composite: The first and second surface layer premixes are melt-extruded at 170°C, while the middle sound insulation layer premixes are melt-extruded at 160°C. Each melt is then filtered through a 200-mesh metal filter. After filtration, the melts are fed into a three-layer co-extrusion die, with the die temperature controlled at 175°C, and distributed through the flow channel to form a three-layer gradient melt film.

[0046] Casting cooling and post-processing: The molten film was cast onto a three-section cooling roller assembly at temperatures of 85℃, 55℃, and 30℃ respectively, with a traction speed of 2 m / min. After cooling, the film was measured for thickness online using laser technology (accuracy ±0.005 mm), and the edges were trimmed to a width of 1.35 m. Then, it was embossed at 45℃ and 0.4 MPa, with a pattern depth of 7.5 μm. After embossing, the traction tension was controlled at 60 N for winding, with a winding alignment error ≤1 mm.

[0047] Aging process: After winding, the membrane material was placed in an environment of 23℃ and 30% relative humidity for 72 hours to obtain a binary composite plasticized gradient structure PVB interlayer membrane.

[0048] Example 2 This embodiment provides a binary compound plasticized gradient structure PVB interlayer film.

[0049] (1) Structural design: The intermediate membrane is a three-layer gradient structure with a total thickness of 1.0 mm. The thickness of the first surface layer and the second surface layer is 0.4 mm, and the thickness of the middle sound insulation layer is 0.2 mm.

[0050] (2) Raw material composition The first and second surface layers (with identical compositions) consist of: 100 parts by weight of a first PVB resin (weight-average molecular weight 190,000, hydroxyl content 20 mol%, degree of acetylation 0.8 mol%, degree of acetalization 67 mol%); 30 parts by weight of a first compound plasticizer (diethylene glycol dibenzoate and 3GO, mass ratio 1:3); a UV shielding agent (2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole); an antioxidant (2,6-di-tert-butyl-p-cresol and tris(2,4-di-tert-butylphenyl) phosphite, mass ratio 2:1); and a metal salt (magnesium acetate and potassium 2-ethylhexanoate, mass ratio 1:2). The surface layer contains 0.5% UV shielding agent, 0.25% antioxidant, and 60 ppm metal salt.

[0051] Intermediate sound insulation layer: 100 parts by weight of second PVB resin (weight average molecular weight 70,000, hydroxyl content 16 mol%, acetylation degree 8 mol%, acetalization degree 69 mol%); 72 parts by weight of second compound plasticizer (a mixture of dibenzoyl diol esters and 3GH, in a mass ratio of 1:2); heat insulation particles (Cs 0.33 WO3 (with an average particle size of 0.04 μm). The heat-insulating particles in the middle sound-insulating layer comprise 2.5% of the total mass.

[0052] (3) Preparation Raw material pretreatment: The first and second PVB resins were dried at 88℃ and -0.085MPa for 5 hours. Diethylene glycol dibenzoate and 3GO were stirred at 68℃ and 400 rpm for 17 minutes in a specific ratio to obtain the first compound plasticizer. A mixture of diethylene glycol dibenzoate and 3GH was stirred at 68℃ and 400 rpm for 17 minutes in a specific ratio to obtain the second compound plasticizer. Insulating particles were added to 3GH (mass ratio of insulating particles to 3GH: 1:10) and dispersed at 68℃ and 2800 rpm for 35 minutes. After dispersion, the particles were ground to a particle size ≤0.05μm to obtain an insulating particle dispersion.

[0053] Preparation of premixes for each layer: The first PVB resin, the first compound plasticizer, and other additives (UV shielding agent, antioxidant, and metal salt) were mixed at 85°C and 650 r / min for 35 min to obtain the first surface layer premix and the second surface layer premix. The second PVB resin and the second compound plasticizer were mixed at 80°C and 750 r / min for 25 min, and then the heat insulation particle dispersion was added and the mixture was mixed for another 17 min to obtain the intermediate sound insulation layer premix.

[0054] Melt extrusion, co-extrusion composite: The first and second surface layer premixes are melt-extruded at 175°C, while the middle sound insulation layer premix is ​​melt-extruded at 165°C. Each melt is then filtered through a 200-mesh metal screen. After filtration, the melts are fed into a three-layer co-extrusion die, with the die temperature controlled at 180°C. The melts are then distributed and compounded into a three-layer gradient melt film through the flow channel.

[0055] Casting cooling and post-processing: The molten film was cast onto a three-section cooling roller assembly at temperatures of 88℃, 58℃, and 32℃, with a traction speed of 2.5 m / min. After cooling, the film was measured online using laser thickness measurement (accuracy ±0.005 mm) and trimmed to a width of 1.35 m. Then, it was embossed at 48℃ and 0.4 MPa, with a pattern depth of 7.5 μm. After embossing, the traction tension was controlled at 70 N for winding, with a winding alignment error ≤1 mm.

[0056] Aging process: After winding, the membrane material was placed in an environment of 23℃ and 30% relative humidity for 72 hours to obtain a binary composite plasticized gradient structure PVB interlayer membrane.

[0057] Example 3 This embodiment provides a binary compound plasticized gradient structure PVB interlayer film.

[0058] (1) Structural design: The intermediate membrane is a three-layer gradient structure with a total thickness of 1.2 mm. The thickness of the first surface layer and the second surface layer is 0.45 mm, and the thickness of the middle sound insulation layer is 0.3 mm.

[0059] (2) Raw material composition The first and second surface layers (with the same composition) consist of: 100 parts by weight of a first PVB resin (weight-average molecular weight of 210,000, hydroxyl content of 24 mol%, degree of acetylation of 1.2 mol%, degree of acetalization of 70 mol%); 26 parts by weight of a first compound plasticizer (diethylene glycol dibenzoate and 3GO, in a mass ratio of 1:2); a UV shielding agent (2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole); an antioxidant (2,6-di-tert-butyl-p-cresol and tris(2,4-di-tert-butylphenyl) phosphite, in a mass ratio of 2:1); and a metal salt (magnesium acetate and potassium 2-ethylhexanoate, in a mass ratio of 1:2). The surface layer contains 0.3% UV shielding agent, 0.15% antioxidant, and 40 ppm metal salt.

[0060] Intermediate sound insulation layer: 100 parts by weight of second PVB resin (weight average molecular weight 80,000, hydroxyl content 20 mol%, degree of acetylation 10 mol%, degree of acetalization 72 mol%); 65 parts by weight of second compound plasticizer (a mixture of dibenzoyl diol esters and 3GH, in a mass ratio of 1:1); heat insulation particles (Cs 0.33 WO3 (with an average particle size of 0.02 μm). The heat-insulating particles in the middle sound-insulating layer comprise 1.8% of the total mass.

[0061] (3) Preparation Raw material pretreatment: The first and second PVB resins were dried at 82℃ and -0.085MPa for 5 hours. Diethylene glycol dibenzoate and 3GO were stirred at 62℃ and 400 rpm for 17 minutes in a specific ratio to obtain the first compound plasticizer. A mixture of diethylene glycol dibenzoate and 3GH was stirred at 62℃ and 400 rpm for 17 minutes in a specific ratio to obtain the second compound plasticizer. Insulating particles were added to 3GH (mass ratio of insulating particles to 3GH: 1:15) and dispersed at 62℃ and 2200 rpm for 35 minutes. After dispersion, the particles were ground to a particle size ≤0.05μm to obtain an insulating particle dispersion.

[0062] Preparation of premixes for each layer: The first PVB resin, the first compound plasticizer, and other additives (UV shielding agent, antioxidant, and metal salt) were mixed at 85°C and 650 r / min for 35 min to obtain the first surface layer premix and the second surface layer premix. The second PVB resin and the second compound plasticizer were mixed at 80°C and 750 r / min for 25 min, and then the heat insulation particle dispersion was added and the mixture was mixed for another 17 min to obtain the intermediate sound insulation layer premix.

[0063] Melt extrusion, co-extrusion composite: The first and second surface layer premixes are melt-extruded at 165°C, while the middle sound insulation layer premixes are melt-extruded at 155°C. Each melt is then filtered through a 200-mesh metal screen. After filtration, the melts are fed into a three-layer co-extrusion die, with the die temperature controlled at 172°C. The melts are then distributed and compounded into a three-layer gradient melt film through the flow channel.

[0064] Casting cooling and post-processing: The molten film was cast onto a three-section cooling roller assembly at temperatures of 82℃, 52℃, and 28℃ respectively, with a traction speed of 1.8 m / min. After cooling, the film was measured online using laser thickness measurement (accuracy ±0.005 mm) and trimmed to a width of 1.35 m. Then, it was embossed at 42℃ and 0.4 MPa, with a pattern depth of 7.5 μm. After embossing, the traction tension was controlled at 55 N for winding, with a winding alignment error ≤1 mm.

[0065] Aging process: After winding, the membrane material was placed in an environment of 23℃ and 30% relative humidity for 72 hours to obtain a binary composite plasticized gradient structure PVB interlayer membrane.

[0066] Example 4 This embodiment provides a binary compound plasticized gradient structure PVB interlayer film.

[0067] (1) Structural design: The intermediate membrane is a three-layer gradient structure with a total thickness of 0.7 mm. The thickness of the first surface layer and the second surface layer is 0.25 mm, and the thickness of the middle sound insulation layer is 0.2 mm.

[0068] (2) Raw material composition The first and second surface layers (with the same composition) consist of: 100 parts by weight of a first PVB resin (weight-average molecular weight of 180,000, hydroxyl content of 18 mol%, degree of acetylation of 0.6 mol%, degree of acetalization of 66 mol%); 32 parts by weight of a first compound plasticizer (diethylene glycol dibenzoate and 3GO, in a mass ratio of 1:2.5); a UV shielding agent (2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole); an antioxidant (2,6-di-tert-butyl-p-cresol and tris(2,4-di-tert-butylphenyl) phosphite, in a mass ratio of 2:1); and a metal salt (magnesium acetate and potassium 2-ethylhexanoate, in a mass ratio of 1:2). The surface layer contains 0.6% UV shielding agent, 0.3% antioxidant, and 80 ppm metal salt.

[0069] Intermediate sound insulation layer: 100 parts by weight of second PVB resin (weight average molecular weight 65,000, hydroxyl content 14 mol%, acetylation degree 7 mol%, acetalization degree 68 mol%); 75 parts by weight of second compound plasticizer (a mixture of dibenzoyl diol esters and 3GH, in a mass ratio of 1:1.5); heat insulation particles (Cs 0.33 WO3 (with an average particle size of 0.05 μm). The heat-insulating particles in the middle sound-insulating layer comprise 3% of the total mass.

[0070] (3) Preparation Raw material pretreatment: The first and second PVB resins were dried at 90℃ and -0.085MPa for 5 hours. Diethylene glycol dibenzoate and 3GO were stirred at 70℃ and 400 rpm for 17 minutes in a specific ratio to obtain the first compound plasticizer. A mixture of diethylene glycol dibenzoate and 3GH was stirred at 70℃ and 400 rpm for 17 minutes in a specific ratio to obtain the second compound plasticizer. Insulating particles were added to 3GH (mass ratio of insulating particles to 3GH: 1:8) and dispersed at 70℃ and 3000 rpm for 35 minutes. After dispersion, the particles were ground to a particle size ≤0.05μm to obtain an insulating particle dispersion.

[0071] Preparation of premixes for each layer: The first PVB resin, the first compound plasticizer, and other additives (UV shielding agent, antioxidant, and metal salt) were mixed at 85°C and 650 r / min for 35 min to obtain the first surface layer premix and the second surface layer premix. The second PVB resin and the second compound plasticizer were mixed at 80°C and 750 r / min for 25 min, and then the heat insulation particle dispersion was added and the mixture was mixed for another 17 min to obtain the intermediate sound insulation layer premix.

[0072] Melt extrusion, co-extrusion composite: The first and second surface layer premixes are melt-extruded at 180°C, while the middle sound insulation layer premix is ​​melt-extruded at 170°C. Each melt is then filtered through a 200-mesh metal screen. After filtration, the melts are fed into a three-layer co-extrusion die, with the die temperature controlled at 185°C. The melts are then distributed and compounded into a three-layer gradient melt film through the flow channel.

[0073] Casting cooling and post-processing: The molten film was cast onto a three-stage cooling roller assembly with roller temperatures of 90℃, 60℃, and 35℃ respectively, and a traction speed of 3 m / min. After cooling, the film was measured for thickness online using laser technology (accuracy ±0.005 mm), and the edges were trimmed to a width of 1.35 m. Then, it was embossed at 50℃ and 0.4 MPa, with a pattern depth of 7.5 μm. After embossing, the traction tension was controlled at 80 N for winding, with a winding alignment error ≤1 mm.

[0074] Aging process: After winding, the membrane material was placed in an environment of 23℃ and 30% relative humidity for 72 hours to obtain a binary composite plasticized gradient structure PVB interlayer membrane.

[0075] Comparative Example 1 This comparative example provides a PVB interlayer film, which differs from Example 1 only in that the first compound plasticizer is modified to a single 3GO (28 parts by weight), and the second compound plasticizer is modified to a single 3GH (68 parts by weight).

[0076] Comparative Example 2 This comparative example provides a PVB interlayer film, which differs from Example 1 only in that: the first compound plasticizer is modified to a mixture of glycol dibenzoate and 3GH in a mass ratio of 1:1.5 (28 parts by weight), and the second compound plasticizer is modified to diethylene glycol dibenzoate and 3GO in a mass ratio of 1:2.5 (68 parts by weight).

[0077] Comparative Example 3 This comparative example provides a PVB interlayer film, which differs from Example 1 only in that: the first compound plasticizer is modified to 3GO and 3GH in a mass ratio of 4:1 (28 parts by weight), and the second compound plasticizer is modified to 3GO and 3GH in a mass ratio of 4:1 (68 parts by weight).

[0078] Experimental Example 1 The intermediate films prepared in Examples 1-4 and Comparative Examples 1-3 were respectively made into laminated glasses, and the specific steps are as follows: The first glass substrate, the intermediate film, and the second glass substrate are sequentially stacked and placed in a vacuum laminator for pre-pressing at 95°C and -0.093MPa for 35 minutes. The pre-pressed composite is then transferred to an autoclave and subjected to high-temperature and high-pressure pressing at 130°C and 1.35MPa for 75 minutes to form a strong and dense bond between the intermediate film and the glass substrate, thereby obtaining the laminated glass.

[0079] The following performance tests were performed on the obtained laminated glass and interlayer: (1) First light irradiation test: Four cycles of test were conducted according to the method described in patent CN110352181A, and the void state at the end of the intermediate film was observed and recorded. The test conditions were as follows: after irradiating xenon light for 144 hours at a black plate temperature of 83℃, a tank temperature of 50℃, and a humidity of 50%RH, the film was immersed in pure water at 80℃ for 24 hours (water tank depth 15cm), and then dried at 23℃ and 50% humidity for 4 hours. This constituted one cycle; the xenon light irradiance was 180W / m². 2 (Wavelength 300~400nm), using an internal quartz filter and an external quartz #275 filter (cutoff value 275nm); when the visible light transmittance of the two glass plates is the same, irradiation is performed from the side of the first glass plate, and when they are different, irradiation is performed from the side with higher transmittance.

[0080] (2) Second light irradiation test: Seven cycles of test were conducted according to the method described in patent CN110352181A, and the void state at the end of the intermediate membrane was observed and recorded. The test conditions were the same as those in (1) above.

[0081] (3) Molecular weight retention rate and distribution change ratio: The weight-average molecular weight (M) of PVB resin before and after the first light irradiation test was determined by GPC method. w ) and number-average molecular weight (M n ), calculate the molecular weight retention rate (M after the experiment) w / M before the test w ×100%) and the distribution change ratio (M after the experiment) w / M n Divide by M before the experiment w / M n Similarly, the molecular weight retention rate and distribution change ratio before and after the second light irradiation test were determined using the same method.

[0082] (4) Sound insulation performance: The sound insulation performance at 315Hz frequency at 23℃ was tested according to GB / T 18696.2-2002 standard.

[0083] (5) Visible light transmittance: measured in the wavelength range of 380~780nm according to JIS R3211:1998 standard.

[0084] (6) Bond strength: Tested in accordance with GB / T 14683-2017 standard.

[0085] (7) Infrared blocking rate: The infrared blocking rate in the wavelength range of 780~2500nm was tested.

[0086] (8) Plasticizer migration rate: After the intermediate film is aged in an environment of 80°C for 1000 hours, the residual amount of plasticizer on the surface is measured and the migration rate is calculated.

[0087] The performance test results are recorded in Table 1.

[0088] Table 1 Performance Test Results

[0089] As shown in Table 1, the binary composite plasticized gradient structure PVB interlayer membranes prepared by the present invention (Examples 1-4) are significantly superior to those of Comparative Examples 1-3 in many key performance indicators. The present invention successfully solves the technical problems of traditional PVB interlayer membranes, such as poor aging resistance, insufficient sound insulation, easy plasticizer migration, and difficulty in achieving multiple functions, by constructing a proprietary binary composite plasticizing system of "diethylene glycol dibenzoate / 3GO for the surface layer" and "diethylene glycol dibenzoate mixture / 3GH for the interlayer," and synergizing it with a three-layer gradient structure, specific resin molecular weight, functional particles, and optimized processes. This results in a high-performance PVB interlayer membrane with excellent anti-porosity, good sound and heat insulation effects, strong adhesion, and high long-term stability.

[0090] Therefore, through innovative material system design and process optimization, this invention provides a PVB interlayer and laminated glass with excellent comprehensive performance and long-term durability, effectively overcoming the shortcomings of existing technologies and having important application value in high-end safety glass fields such as automobiles and buildings.

[0091] 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 binary composite plasticized gradient structure PVB interlayer film, characterized in that, The intermediate membrane has a three-layer gradient structure, consisting of a first surface layer, a middle sound-insulating layer, and a second surface layer from the outside to the inside. Both the first surface layer and the second surface layer contain a first PVB resin and a first compound plasticizer, wherein the first compound plasticizer includes diethylene glycol dibenzoate and 3GO; The intermediate sound insulation layer comprises a second PVB resin and a second compound plasticizer, wherein the second compound plasticizer comprises a mixture of dibenzoyl diol esters and 3GH; the mixture of dibenzoyl diol esters comprises dipropylene glycol dibenzoate, diethylene glycol dibenzoate and propylene glycol dibenzoate.

2. The binary composite plasticized gradient structure PVB interlayer film according to claim 1, characterized in that, In the first compound plasticizer, the mass ratio of diethylene glycol dibenzoate to 3GO is 1:(2~3); the mass ratio of the first PVB resin to the first compound plasticizer is 100:(25~32).

3. The binary composite plasticized gradient structure PVB interlayer film according to claim 1, characterized in that, In the second compound plasticizer, the mass ratio of the dibenzoyl diol mixture to 3GH is 1:(1~2); the mass ratio of the second PVB resin to the second compound plasticizer is 100:(60~75).

4. The binary composite plasticized gradient structure PVB interlayer film according to claim 1, characterized in that, The first PVB resin has a weight-average molecular weight of 180,000 to 220,000 and a hydroxyl content of 10 to 26 mol; the second PVB resin has a weight-average molecular weight of 65,000 to 85,000 and a hydroxyl content of 12 to 25 mol.

5. The binary composite plasticized gradient structure PVB interlayer film according to claim 1, characterized in that, The first and second surface layers also contain ultraviolet shielding agents, antioxidants, and metal salts, respectively; the intermediate sound insulation layer also contains heat-insulating particles.

6. The binary composite plasticized gradient structure PVB interlayer film according to claim 1, characterized in that, The thickness ratio of the first surface layer, the intermediate sound insulation layer, and the second surface layer is (35~45):(10~30):(35~45); the total thickness of the intermediate film is 0.6~1.5mm.

7. A method for preparing a binary compound plasticized gradient structure PVB interlayer as described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Prepare the first surface layer premix, the middle sound insulation layer premix, and the second surface layer premix respectively; S2. The first surface layer premix, the middle sound insulation layer premix, and the second surface layer premix are melt-extruded separately and co-extruded to form a gradient structure melt film. S3. The gradient structure molten film is sequentially subjected to casting, cooling, and curing treatments to obtain the binary compound plasticized gradient structure PVB intermediate film.

8. The method according to claim 7, characterized in that, In S2, the melt extrusion temperatures of the first surface layer premix and the second surface layer premix are 160~180℃, respectively; the melt extrusion temperature of the intermediate sound insulation layer premix is ​​150~170℃.

9. The method according to claim 7, characterized in that, In S3, the aging process is carried out at a temperature of 20-25°C, a relative humidity of 25-35%, and a time of 66-78 hours.

10. A laminated glass, characterized in that, It includes two glass substrates arranged opposite each other, and a binary composite plasticized gradient structure PVB interlayer film as described in any one of claims 1 to 6 sandwiched between the two glass substrates.

Images