Liquid adhesive for high-transmittance privacy laminated glass and preparation method thereof
Patent Information
- Application Number
- CN202610912277.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-24
- Publication Date
- 2026-09-25
AI Technical Summary
[0005]针对现有技术中夹层玻璃用液态胶难以兼顾高透光与防窥雾度、粒子易团聚等问题，本发明提供了一种高透光防窥夹层玻璃用液态胶及其制备方法
[0012]本发明的有益效果是：该液态胶通过三层阶跃折射率微球产生可控散射，在透光率≥85%的同时实现雾度28-60%可调，满足不同场景防窥需求；通过微球表面改性与预分散工艺解决了低掺量下均匀分散难题；微球低收缩交联内核设计削弱了长期温变下的界面微应力，保障光学稳定性；采用紫外光固化，能耗低、周期短，且剥离强度为8-10N/cm、落球冲击不脱层，兼具优异的安全粘接性能，易于工业化生产。
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Abstract
Description
Technical Field
[0001] This invention relates to the field of laminated glass technology, specifically to a liquid adhesive for high-transmittance privacy laminated glass and its preparation method. Background Technology
[0002] Laminated glass is widely used in building curtain walls, bathroom partitions and office partitions. With people’s increasing demand for privacy protection, laminated glass, which combines good lighting and privacy protection, has become a market hotspot.
[0003] Currently, the main technical approaches to achieving privacy features include surface coatings, frosted glass, and adding scattering particles to the interlayer adhesive. However, surface coatings suffer from poor weather resistance and are prone to peeling; frosted glass exhibits a significant decrease in light transmittance and is prone to accumulating dirt; existing liquid adhesives with added scattering particles generally face the dilemma of balancing high light transmittance with high haze, and also suffer from defects such as particle agglomeration, poor dispersion uniformity, and unstable optical performance. Furthermore, traditional laminated glass using polyvinyl butyral (PVB) films requires high-temperature and high-pressure processing, resulting in high energy consumption, long processing times, and poor flexibility in haze adjustment.
[0004] Therefore, developing a liquid adhesive material with high light transmittance, adjustable privacy protection, simple processing, and stable performance has significant market value. Summary of the Invention
[0005] To address the problems of existing liquid adhesives for laminated glass, such as difficulty in simultaneously achieving high light transmittance and privacy-preventing haze, and the tendency for particle agglomeration, this invention provides a high-light-transmittance privacy-preventing liquid adhesive for laminated glass and its preparation method. This liquid adhesive uses polyurethane acrylate as a matrix and adds three layers of step-index polymer microspheres, achieving a light transmittance ≥85% while maintaining an adjustable haze of 30-60%. Furthermore, the microspheres are uniformly dispersed, UV-cured, and easily mass-produced.
[0006] To achieve the above objectives, the present invention adopts the following technical solution: A liquid adhesive for high-transmittance privacy laminated glass, wherein the liquid adhesive is prepared from the following raw materials in parts by weight: 70-95 parts of polyurethane acrylate prepolymer, 0.1-5 parts of polymer microspheres, 0.5-3 parts of photoinitiator, 0.1-1 parts of leveling agent, and 0.05-0.5 parts of silane coupling agent; The polymer microspheres consist of a high-refractive-index core, a medium-refractive-index intermediate layer, and a low-refractive-index surface layer, forming a three-layer step-refractive-index structure from the inside out. The particle size of the polymer microspheres is 3-10 μm, accounting for 0.1-0.5 wt% of the total weight of the liquid adhesive. The polymer microspheres are surface-modified with a silane coupling agent, and their core adopts a low-shrinkage cross-linked structure.
[0007] Preferably, the photoinitiator is at least one of α-hydroxy ketone photoinitiators or acylphosphine oxide photoinitiators; the leveling agent is at least one of silicone leveling agents or polyacrylate leveling agents.
[0008] Preferably, the polymer microspheres are prepared by seed emulsion polymerization or layer-by-layer coating, with the core material being cross-linked polystyrene or cross-linked polymethyl methacrylate, and the intermediate and surface layers being acrylate copolymers with different monomer ratios.
[0009] Preferably, the silane coupling agent is γ-methacryloyloxypropyltrimethoxysilane or γ-glycidoxypropyltrimethoxysilane.
[0010] Preferably, the light transmittance of the cured liquid adhesive layer is ≥85%, and the haze is 28%-60%.
[0011] Preferably, the preparation method of the liquid adhesive for high-transmittance privacy laminated glass includes the following specific preparation steps: S1. Add the polymer microspheres and silane coupling agent to a high-speed mixer and stir at 800-1500 rpm for 15-30 min at room temperature to obtain surface-modified polymer microspheres. S2. The modified polymer microspheres obtained in S1 are mixed with a portion of the prepolymer accounting for 10-30 wt% of the total amount of polyurethane acrylate prepolymer. The mixture is dispersed at 20-40℃ using a high-shear emulsifier at a linear velocity of 10-20 m / s for 20-40 min, or by grinding and dispersing 2-5 times using a three-roll mill at a speed of 150-300 rpm, to prepare a pre-dispersed masterbatch with a microsphere content of 5-15 wt%. S3. Add the pre-dispersed masterbatch obtained in S2, the remaining polyurethane acrylate prepolymer, photoinitiator and leveling agent to the reactor. Under light-protected conditions, control the temperature at 25-35℃ and stir at 300-500 rpm for 10-20 min. Then, under vacuum conditions of -0.08 to -0.1 MPa, degas for 15-30 min to obtain a uniform liquid adhesive composition. S4. Apply the liquid adhesive composition obtained in S3 between two glass layers by coating or pouring, controlling the adhesive layer thickness to be 0.38-1.52 mm, and cure it with ultraviolet light under the following conditions: ultraviolet light wavelength of 365-395 nm, light intensity of 30-50 mW / cm2, and curing time of 15-30 min, to form a laminated glass adhesive layer.
[0012] The beneficial effects of this invention are as follows: the liquid adhesive generates controllable scattering through three layers of step-refractive-index microspheres, achieving adjustable haze of 28-60% while maintaining a light transmittance of ≥85%, meeting the privacy requirements of different scenarios; the microsphere surface modification and pre-dispersion process solves the problem of uniform dispersion at low dosages; the low-shrinkage cross-linked core design of the microspheres weakens the interfacial micro-stress under long-term temperature changes, ensuring optical stability; it is cured by ultraviolet light, with low energy consumption, short cycle, peel strength of 8-10 N / cm, no delamination upon drop ball impact, excellent safe bonding performance, and easy industrial production. Detailed Implementation
[0013] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0014] Example 1: A liquid adhesive for high-transmittance privacy laminated glass in Example 1 is prepared from the following raw materials in parts by weight: 70 parts of polyurethane acrylate prepolymer, 0.1 parts of polymer microspheres, 0.5 parts of photoinitiator (2,4,6-trimethylbenzoyl-diphenylphosphine oxide), 0.1 parts of leveling agent (polyether-modified polydimethylsiloxane), and 0.05 parts of silane coupling agent (γ-methacryloyloxypropyltrimethoxysilane). The preparation method of the polyurethane acrylate prepolymer is as follows: S1. In a four-necked flask equipped with a stirrer, thermometer and reflux condenser, add 1 mol polyethylene glycol 1000 and 2.2 mol isophorone diisocyanate (IPDI), add 0.5% of the total mass of the reactants as catalyst dibutyltin dilaurate, under nitrogen protection, control the reaction temperature at 70℃, stir at 300 rpm for 4 hours to obtain the terminal isocyanate prepolymer; S2. Add 2.2 mol of hydroxyethyl acrylate (HEA) and 0.3% of hydroquinone as a polymerization inhibitor to the terminal isocyanate prepolymer obtained in S1. Continue the reaction at 75°C and 300 rpm for 3 hours. Cool to below 50°C to obtain polyurethane acrylate prepolymer.
[0015] The preparation method of the polymer microspheres is as follows: S1. In a four-necked flask equipped with a stirrer, thermometer and reflux condenser, add 500 mL of deionized water and 2.5 g of sodium dodecyl sulfate. After stirring to dissolve, add 100 g of styrene, 10 g of divinylbenzene and 2 g of azobisisobutyronitrile. Replace the air in the reactor with nitrogen gas, stir at 250 rpm for 30 min, raise the temperature to 75 °C and react for 7 h to obtain cross-linked polystyrene seed microsphere emulsion. S2. Slowly add a mixed monomer solution (composed of 50g styrene, 50g methyl methacrylate, 5g divinylbenzene and 1g azobisisobutyronitrile) to the seed microsphere emulsion obtained in S1, controlling the drop rate at 0.8mL / min, and continue the reaction at 75℃ for 5h to form a medium refractive index intermediate layer on the surface of the seed microspheres, thus obtaining a double-layered core-shell microsphere. S3. To the bilayer core-shell microsphere emulsion obtained in S2, a mixed monomer solution (composed of 100g methyl methacrylate, 5g divinylbenzene and 1g azobisisobutyronitrile) was added dropwise at a rate of 0.8mL / min. The reaction was continued at 75℃ for 5h, forming a low refractive index surface layer (polymethyl methacrylate) on the outermost layer, resulting in polymer microspheres with a three-layer step refractive index structure. After the reaction was completed, the mixture was cooled to room temperature, washed three times with anhydrous ethanol, centrifuged at 8000rpm for 10min, and freeze-dried at -50℃ for 24h to obtain white powdery polymer microspheres with an average particle size of 5.6μm.
[0016] This embodiment describes a method for preparing a liquid adhesive for high-transmittance privacy laminated glass. The specific preparation steps are as follows: S1. Add the polymer microspheres and silane coupling agent to a high-speed mixer and stir at 1000 rpm for 20 min at room temperature to obtain surface-modified polymer microspheres. S2. The modified polymer microspheres obtained in S1 are mixed with a portion of the prepolymer accounting for 20wt% of the total amount of polyurethane acrylate prepolymer. The mixture is then dispersed at 25°C using a high-shear emulsifier at a linear velocity of 15m / s for 30min to prepare a predispersed masterbatch with a microsphere content of 8wt%. S3. Add the pre-dispersed masterbatch obtained in S2, the remaining polyurethane acrylate prepolymer, photoinitiator and leveling agent to the reactor. Under light-protected conditions, control the temperature at 25°C and stir at 400 rpm for 15 min. Then, under vacuum conditions of -0.09 MPa, degas for 20 min to obtain a uniform liquid adhesive composition. S4. The liquid adhesive composition obtained in S3 is poured between two layers of glass, and the thickness of the adhesive layer is controlled to be 0.38 mm. It is then cured by ultraviolet light under the following conditions: ultraviolet light wavelength of 365 nm, light intensity of 40 mW / cm2, and curing time of 15 min, to form a laminated glass adhesive layer.
[0017] Example 2: A liquid adhesive for high-transmittance privacy laminated glass in Example 2 is prepared from the following raw materials in parts by weight: The composition includes 83 parts of polyurethane acrylate prepolymer, 2.6 parts of polymer microspheres, 1.8 parts of photoinitiator (2,4,6-trimethylbenzoyl-diphenylphosphine oxide), 0.6 parts of leveling agent (polyether-modified polydimethylsiloxane), and 0.3 parts of silane coupling agent (γ-methacryloyloxypropyltrimethoxysilane). The preparation methods of the polyurethane acrylate prepolymer and polymer microspheres in Example 2 are the same as those in Example 1; The preparation method of the liquid adhesive for high-transmittance privacy laminated glass in Example 2 is the same as that in Example 1, with an adhesive layer thickness of 0.76 mm and a curing time of 25 min.
[0018] Example 3: A liquid adhesive for high-transmittance privacy laminated glass in Example 3 is prepared from the following raw materials in parts by weight: 95 parts of polyurethane acrylate prepolymer, 5 parts of polymer microspheres, 3 parts of photoinitiator (2,4,6-trimethylbenzoyl-diphenylphosphine oxide), 1.0 part of leveling agent (polyether-modified polydimethylsiloxane), and 0.5 parts of silane coupling agent (γ-methacryloyloxypropyltrimethoxysilane). The preparation methods of the polyurethane acrylate prepolymer and polymer microspheres in Example 3 are the same as those in Example 1; The preparation method of the liquid adhesive for high-transmittance privacy laminated glass in Example 3 is the same as that in Example 1, with an adhesive layer thickness of 1.14 mm and a curing time of 35 min.
[0019] Comparative Example 1: The liquid adhesive of Comparative Example 1 was prepared from the following parts by weight of raw materials: 83 parts of polyurethane acrylate prepolymer, 1.8 parts of photoinitiator (2,4,6-trimethylbenzoyl-diphenylphosphine oxide), 0.6 parts of leveling agent (polyether-modified polydimethylsiloxane), and 0.3 parts of silane coupling agent (γ-methacryloyloxypropyltrimethoxysilane). The preparation method of the polyurethane acrylate prepolymer in Comparative Example 1 is the same as that in Example 1; The preparation method of the liquid gel in Comparative Example 1 is the same as that in Example 1, except that polymer microspheres are not added.
[0020] Comparative Example 2: The liquid adhesive of Comparative Example 2 was prepared from the following parts by weight of raw materials: 83 parts of polyurethane acrylate prepolymer, 2.6 parts of ordinary polymer microspheres, 1.8 parts of photoinitiator (2,4,6-trimethylbenzoyl-diphenylphosphine oxide), 0.6 parts of leveling agent (polyether-modified polydimethylsiloxane), and 0.3 parts of silane coupling agent (γ-methacryloyloxypropyltrimethoxysilane). The preparation method of ordinary polymer microspheres is as follows: S1. In a four-necked flask equipped with a stirrer, thermometer and reflux condenser, add 500 mL of deionized water and 2.5 g of sodium dodecyl sulfate. After stirring to dissolve, add 100 g of styrene, 10 g of divinylbenzene and 2 g of azobisisobutyronitrile. Replace the air in the reactor with nitrogen gas, stir at 250 rpm for 30 min, raise the temperature to 75 °C and react for 8 h to obtain cross-linked polystyrene microsphere emulsion. S2. After the reaction is complete, the mixture is cooled to room temperature, washed three times with anhydrous ethanol, centrifuged at 8000 rpm for 10 min, and freeze-dried at -50℃ for 24 h to obtain white powdery ordinary polymer microspheres with an average particle size of 5.2 μm.
[0021] The preparation method of the polyurethane acrylate prepolymer in Comparative Example 2 is the same as that in Example 1; The preparation method of the liquid gel in Comparative Example 2 is the same as that in Example 1, except that ordinary polymer microspheres are used.
[0022] Performance testing 1. Light transmittance and haze test According to GB / T 2410-2008 "Test Methods for Light Transmittance and Haze of Transparent Plastics", an integrating sphere haze meter was used for testing. The prepared laminated glass sample was cut into 50mm×50mm specimens, ensuring that the specimen surface was flat, free of scratches and oil stains. Under the environmental conditions of 23±2℃ and 50±5% relative humidity, after the haze meter was turned on and preheated and stabilized, the instrument zero point and 100% light transmittance were calibrated with a standard plate. Then, the specimen was placed close to the entrance window of the integrating sphere, and the total light transmittance Tt and the scattered light flux Td were read respectively. The haze value was calculated according to the formula haze (%) = Td / Tt×100%. At least 3 parallel specimens were tested for each sample, and the arithmetic mean was taken as the final result.
[0023] Table 1. Test data of transmittance and haze for different samples
[0024] Examples 1-3 all exhibit light transmittance exceeding 85%, with haze adjustable within the range of 28.6%-68.3%. Example 2, with a haze of 51.5%, is most suitable for privacy in bathrooms. Comparative Example 1 has a haze of only 1.8%, offering no privacy function; Comparative Example 2 has a haze of 23.8%, lower than Example 2 with the same amount of added material. This demonstrates that the present invention achieves high light transmittance and a wide range of adjustable haze through three layers of step microspheres, with scattering efficiency superior to ordinary solid microspheres.
[0025] 2. Peel strength test The laminated glass sample was cut into specimens 25 mm wide and 200 mm long. The adhesive layer was pre-peeled from the glass by about 10 mm at one end of the specimen as the peeling start. After conditioning for at least 4 hours under environmental conditions of 23±2℃ and 50±5% relative humidity, the glass part of the specimen was fixed in the lower clamp of the tensile testing machine. The pre-peeled adhesive layer (together with the second glass layer) was bent upwards by 180° and clamped in the upper clamp, ensuring that the peeling surface was aligned with the force line. Peeling was performed at a constant tensile speed of 100 mm / min, and the force value change during the peeling process was continuously recorded. The effective peeling length was at least 100 mm. The average value of the peeling force in the stable region was taken, and the peeling strength (N / cm) was calculated as average peeling force (N) / specimen width (cm). At least 3 parallel specimens were tested for each sample, and the arithmetic mean was taken as the final result.
[0026] Table 2. Peel strength test data for different samples
[0027] The peel strengths of Examples 1-3 ranged from 8.1 to 9.6 N / cm, all exceeding 8 N / cm, thus meeting the safety requirements for laminated glass bonding. The peel strength of Comparative Example 2 was slightly lower than that of Example 2, indicating that the three-layer step microspheres had a relatively small negative impact on bonding performance. All examples met the safety bonding requirements.
[0028] 3. Drop ball impact test Cut the laminated glass sample into 610mm × 610mm specimens and conditioned them for at least 4 hours at a temperature of 23±2℃ and a relative humidity of 50±5%. Place the specimen horizontally on a specimen support consisting of two machined steel frames, each 15mm wide. Rubber pads with a thickness of 3mm and a hardness of Shore A50 are placed on the contact surfaces of the two frames. The lower steel frame is placed on a steel box approximately 150mm high. A quenched steel ball with a mass of 1040g and a diameter of 63.5mm is dropped freely from a height of 1200mm above the specimen surface. The impact point should be located within a circle with a radius of 25mm centered on the geometric center of the specimen. Observe the failure state of the samples: If the glass is not broken, prepare independent samples for testing at drop heights of 1200mm, 1500mm, 1900mm, 2400mm, 3000mm, 3800mm, and 4800mm, with at least 3 parallel samples tested at each height; if the sample fails, the criteria are: the steel ball should not penetrate the sample, the sample should not break into separate pieces, and in the part where glass has peeled off, the middle layer should not expose a smooth surface, but should be firmly covered by glass fragments. Test 3 parallel samples for each sample, and record the impact history and failure state of each sample.
[0029] Table 3. Drop ball impact test data for different samples
[0030] All samples showed no penetration or delamination at a standard height of 1200 mm, meeting the impact resistance safety requirements. At the same dosage, the failure height of Example 2 was 2400 mm, significantly higher than the 1500 mm of Comparative Example 2, indicating that the three-layer step microspheres, due to their multi-layer interface design, alleviated stress concentration and had less negative impact on impact resistance than ordinary solid microspheres.
[0031] 4. Accelerates aging stability The prepared laminated glass samples were cut into 510mm × 360mm specimens and placed in an environment of 23±2℃ and 50±5% RH for at least 24 hours for conditioning. The initial transmittance and initial haze values of the specimens were measured. Then, the specimens were placed vertically in a constant temperature and humidity test chamber, with a distance of not less than 15mm between specimens. The test conditions were set to 85±2℃ and 85±5%RH, and the test was conducted continuously for 500 hours. During the test, the temperature and humidity of the test chamber were checked every 24 hours. Record the temperature to ensure the equipment is operating normally; after the test, close the test chamber and allow it to cool naturally to room temperature. Take out the sample and place it in an environment with a temperature of 23±2℃ and a relative humidity of 50±5% for 24 hours for recovery treatment. Then measure the transmittance and haze value of the sample again. Calculate the transmittance attenuation rate ((initial transmittance - transmittance after aging) / initial transmittance × 100%) and haze change rate (haze after aging - initial haze) respectively. Test 3 parallel samples for each sample and take the arithmetic mean as the final result.
[0032] Table 4. Accelerated aging stability test data for different samples
[0033] Examples 1-3 showed excellent aging resistance with a transmittance decrease of ≤3.0% and a haze change of ≤3.6% after aging. At the same addition amount, Example 2 showed significantly better transmittance decrease and haze change than Comparative Example 2, demonstrating that the three-layer step microspheres, through their multi-layer interface and cross-linked core design, effectively suppressed interfacial micro-stress and structural coarsening during long-term aging, exhibiting superior stability compared to ordinary solid microspheres.
Claims
1. A liquid adhesive for high-transmittance privacy laminated glass, characterized in that, The liquid adhesive is prepared from the following raw materials in parts by weight: 70-95 parts of polyurethane acrylate prepolymer, 0.1-5 parts of polymer microspheres, 0.5-3 parts of photoinitiator, 0.1-1 parts of leveling agent, and 0.05-0.5 parts of silane coupling agent; The polymer microspheres consist of a high-refractive-index core, a medium-refractive-index intermediate layer, and a low-refractive-index surface layer, forming a three-layer step-refractive-index structure from the inside out. The particle size of the polymer microspheres is 3-10 μm, accounting for 0.1-0.5 wt% of the total weight of the liquid adhesive. The polymer microspheres are surface-modified with a silane coupling agent, and their core adopts a low-shrinkage cross-linked structure.
2. The liquid adhesive for high-transmittance privacy laminated glass according to claim 1, characterized in that, The photoinitiator is at least one of α-hydroxy ketone photoinitiators or acylphosphine oxide photoinitiators; the leveling agent is at least one of silicone leveling agents or polyacrylate leveling agents.
3. The liquid adhesive for high-transmittance privacy laminated glass according to claim 1, characterized in that, The polymer microspheres are prepared by seed emulsion polymerization or layer-by-layer coating. The core material is cross-linked polystyrene or cross-linked polymethyl methacrylate, and the middle layer and the surface layer are acrylate copolymers with different monomer ratios.
4. The liquid adhesive for high-transmittance privacy laminated glass according to claim 1, characterized in that, The silane coupling agent is γ-methacryloxypropyltrimethoxysilane or γ-glycidoxypropyltrimethoxysilane.
5. The liquid adhesive for high-transmittance privacy laminated glass according to claim 1, characterized in that, The cured liquid adhesive layer has a light transmittance of ≥85% and a haze of 28%-60%.
6. A method for preparing a liquid adhesive for high-transmittance privacy laminated glass according to any one of claims 1-5, characterized in that, The specific preparation steps are as follows: S1. Add the polymer microspheres and silane coupling agent to a high-speed mixer and stir at 800-1500 rpm for 15-30 min at room temperature to obtain surface-modified polymer microspheres. S2. The modified polymer microspheres obtained in S1 are mixed with a portion of the prepolymer accounting for 10-30 wt% of the total amount of polyurethane acrylate prepolymer. The mixture is dispersed at 20-40℃ using a high-shear emulsifier at a linear velocity of 10-20 m / s for 20-40 min, or by grinding and dispersing 2-5 times using a three-roll mill at a speed of 150-300 rpm, to prepare a pre-dispersed masterbatch with a microsphere content of 5-15 wt%. S3. Add the pre-dispersed masterbatch obtained in S2, the remaining polyurethane acrylate prepolymer, photoinitiator and leveling agent to the reactor. Under light-protected conditions, control the temperature at 25-35℃ and stir at 300-500 rpm for 10-20 min. Then, under vacuum conditions of -0.08 to -0.1 MPa, degas for 15-30 min to obtain a uniform liquid adhesive composition. S4. Apply the liquid adhesive composition obtained in S3 between two glass layers by coating or pouring, controlling the adhesive layer thickness to be 0.38-1.52 mm, and cure it with ultraviolet light under the following conditions: ultraviolet light wavelength of 365-395 nm, light intensity of 30-50 mW / cm2, and curing time of 15-30 min, to form a laminated glass adhesive layer.