PVB interlayer for anti-glare laminated glass and method for preparing the same

Abstract

The present application relates to the technical field of laminated glass interlayer film, in particular to a PVB interlayer film for anti-dazzling laminated glass and a preparation method thereof. The PVB interlayer film comprises a first PVB layer and a second PVB layer arranged in a stack; the first PVB layer comprises a spectral absorption material for selectively absorbing light in the wavelength range of 550-750 nm; the surface of the second PVB layer facing the first PVB layer is formed with pseudo-randomly distributed micro-protrusion scattering structures (composed of cross-linked polymer material). The present application organically combines spectral absorption type and physical structure type anti-dazzling technology, and constructs a double-layer in-depth defense system of "first absorption, then scattering". The two mechanisms act on the light path in succession, and the functions are complementary, so that the overall anti-dazzling effect far exceeds a single technical route, and the visual comfort and safety can be significantly improved while efficiently suppressing strong light dazzle.

Description

Technical Field

[0001] This invention relates to the field of interlayer film technology for laminated glass, and in particular to a PVB interlayer film for anti-glare laminated glass and its preparation method. Background Technology

[0002] Laminated glass is widely used in automotive windshields, building curtain walls, and other fields due to its excellent impact resistance and safety. However, when driving at night or in low-light conditions, the intense glare from oncoming vehicles' high beams severely affects the driver's visual clarity and reaction speed, posing a significant traffic safety hazard.

[0003] Currently, anti-glare technologies for laminated glass are mainly divided into two categories: (1) Spectral absorption type anti-glare technology: This type of technology usually adds specific wavelength absorbing dyes, such as ketone phthalocyanine compounds (CN105307997A), to the interlayer of polyvinyl butyral (PVB) to reduce glare intensity by selectively absorbing visible light in the 550-750nm range. However, this technology has obvious limitations: to achieve sufficient anti-glare effect, a high dye concentration is often required, which leads to a decrease in visible light transmittance, a non-neutral hue in the glass, and limited effectiveness in improving visual contrast in dark places (such as the ratio of relative dark visual brightness to relative light visual brightness (L's / Ls)). (2) Physical structure type anti-glare technology: This technology aims to suppress glare by physically scattering or modulating light through surface microstructures. However, existing technologies suffer from a mismatch with the anti-glare requirements of laminated glass. For example, some technologies (EP0563171B1) set a regularly arranged array of raised dots on the PVB surface, primarily to prevent self-adhesion of the film. However, their high dot coverage (10%-60%) and large size (approximately 200 μm in diameter) regular structure not only fails to optimize optical performance but may also generate diffraction glare due to periodic arrangement, thus exacerbating visual interference. On the other hand, although some technologies (such as CN116456930A, applied to ophthalmic implants) propose pseudo-random lattices to avoid regular diffraction, their application scenarios, material systems, and functional objectives are completely different from those of automotive laminated glass, making them unsuitable for direct reference or application in this field. Summary of the Invention

[0004] The purpose of this invention is to address the problems existing in the prior art by providing a PVB interlayer for anti-glare laminated glass and its preparation method. Through innovative double-layer composite structure design and precise multi-parameter coordinated control, it provides an anti-glare laminated glass solution with excellent comprehensive performance, stability, reliability and easy industrialization.

[0005] To achieve the above objectives, the present invention provides a PVB interlayer for anti-glare laminated glass, comprising a first PVB layer and a second PVB layer stacked together. The first PVB layer contains a spectral absorbing material for selectively absorbing light in the wavelength range of 550-750nm; The second PVB layer has a pseudo-randomly distributed micro-protrusion scattering structure on its surface facing the first PVB layer, and the micro-protrusion scattering structure is composed of a cross-linked polymer material.

[0006] Preferably, the spectral absorbing material includes at least one of phthalocyanine compound and vat compound; the content of the spectral absorbing material is 0.002-0.01 wt% based on the weight of PVB resin in the first PVB layer.

[0007] Preferably, the area coverage of the micro-bump scattering structure on the surface of the second PVB layer is 0.1-5%.

[0008] Preferably, the distribution of the micro-bump scattering structure is generated by the Poisson disk sampling algorithm, and the minimum distance between any two micro-bump centers is not less than 1.5 times the average diameter of the micro-bump.

[0009] Preferably, the average diameter of the micro-protrusions in the micro-protrusion scattering structure is 10-100 μm, the average height is 0.5-25 μm, and the surface density is 100-5000 per square centimeter.

[0010] Preferably, the absolute value of the difference between the refractive index of the crosslinked polymer material and the refractive index of the PVB matrix material of the second PVB layer is not greater than 0.005.

[0011] Preferably, the micro-protrusion scattering structure is compressed after the lamination process, with a compression ratio of 20-80%.

[0012] Preferably, the thickness ratio of the first PVB layer to the second PVB layer is 1-5:1-5.

[0013] The present invention also provides a method for preparing the PVB interlayer film for anti-glare laminated glass, comprising the following steps: S1. Prepare a first PVB layer containing the spectral absorption material; form the pseudo-randomly distributed micro-protrusion scattering structure on the surface of the second PVB layer through printing and curing processes; S2. The first PVB layer is laminated with a second PVB layer having a micro-protrusion scattering structure to obtain the PVB interlayer film for anti-glare laminated glass.

[0014] The present invention also provides a laminated glass comprising at least two glass plates and a PVB interlayer film for anti-glare laminated glass disposed between adjacent glass plates.

[0015] The beneficial effects of this invention are as follows: (1) This invention creatively combines spectral absorption and physical structure anti-glare technologies to construct a two-layer, in-depth defense system of "absorption first, scattering later". The incident glare is first selectively filtered out by the spectral absorption material in the first PVB layer to remove the energy of the key wavelength band of 550-750nm. The remaining stray light is further disrupted and modulated at the interface by the pseudo-random micro-protrusion scattering structure on the surface of the second PVB layer. These two mechanisms act sequentially and complement each other in the optical path, producing a synergistic effect of "1+1>2", which makes the overall anti-glare effect far exceed that of a single technology route. It can effectively suppress strong light glare while significantly improving visual comfort and safety.

[0016] (2) By precisely controlling the area coverage of the micro-protrusion scattering structure within a low range (0.1-5%), this invention achieves excellent light scattering capabilities while minimizing its obstruction of directly transmitted light. Simultaneously, by ensuring a high degree of matching between the refractive index of the cross-linked polymer material constituting the scattering structure and the refractive index of the PVB matrix (with an absolute difference not exceeding 0.005), the structure achieves "optical invisibility" after lamination, effectively avoiding additional light loss and increased haze caused by abrupt changes in interface refractive index. This enables laminated glass employing the interlayer film of this invention to simultaneously meet the stringent requirements of high visible light transmittance and low haze.

[0017] (3) Through the above-mentioned synergistic mechanism and precise optical design, this invention can not only suppress the glare of the light source, but also enhance the illumination of details of objects in dark places by optimizing the light path distribution, thereby increasing the L's / Ls ratio of the laminated glass to more than 1.0. This means that when encountering oncoming high beams, the driver can more clearly and comfortably identify the road conditions and obstacles ahead, greatly improving driving safety at night and in low-light environments.

[0018] (4) The micro-protrusion scattering structure on the surface of the second PVB layer is composed of cross-linked polymer material. After curing, this material forms a three-dimensional network structure that can withstand the high temperature and high pressure environment (compression ratio 20-80%) of the subsequent lamination process, and maintains its shape stability after compression without flowing, collapsing or dissolving. Therefore, its anti-glare function can be maintained stably and persistently throughout the entire life cycle of the laminated glass, overcoming the structural failure risk that may exist in non-cross-linked materials.

[0019] (5) The technical solution of this invention has a high degree of design flexibility. By independently adjusting the type and concentration of the first layer of spectral absorption material, the geometric parameters (size, density, coverage, shape) of the second layer of micro-protrusion structure, and the thickness ratio of the two layers, the anti-glare performance, transmittance, and color coordinates can be customized and optimized for different application scenarios (such as different climate zones and vehicle models). In addition, the micro-protrusion structure is prepared using mature printing and curing technology. This process has high precision and efficiency, can be perfectly integrated into the existing PVB film production process, and is easy to achieve large-scale, continuous, and low-cost industrial production, with good prospects for promotion. Detailed Implementation

[0020] This invention provides a PVB interlayer for anti-glare laminated glass, comprising a first PVB layer and a second PVB layer stacked together; the two together constitute a synergistic anti-glare system. The first PVB layer is a spectral absorption layer located on the side facing outdoors during use. This layer uses PVB resin as a matrix and contains plasticizers. Its key feature is that the first PVB layer contains spectral absorption materials for selectively absorbing light in the wavelength range of 550-750nm, thereby initially filtering out the energy in this wavelength range that is prone to causing dizziness. The second PVB layer is a physical scattering layer, located on the side facing indoors during use. This layer also uses PVB resin as a matrix and contains plasticizers. Its core improvement lies in the fact that the surface of the second PVB layer facing the first PVB layer has a pseudo-randomly distributed micro-protrusion scattering structure, which is composed of a cross-linked polymer material.

[0021] In this invention, the PVB resins of the first PVB layer and the second PVB layer are kept consistent in terms of basic parameters such as hydroxyl content and degree of acetylation. It is preferred to use PVB resins with the same parameters to ensure good interlayer compatibility. The hydroxyl content of the PVB resin is 18-25 mol%, the degree of acetylation is 1-5 mol%, and the degree of acetalization is 70-80 mol.

[0022] In this invention, the plasticizers used in the first PVB layer and the second PVB layer can be independently selected from at least one of the following: triethylene glycol di-2-ethylhexanoate (3GO), tetraethylene glycol di-2-ethylhexanoate (4GO), diethylene glycol di-2-ethylhexanoate (2GO), triethylene glycol diheptanoate, triethylene glycol dioctanoate, triethylene glycol dinonanoate, diethylene glycol dinonanoate, diethylene glycol dibenzoate (DEDB), tetraethylene glycol diheptanoate, tetraethylene glycol bis-n-heptanoate (4G7), dibutyl sebacate (DBS), triisononyl trimellitate (TINTM), N-ethyltoluenesulfonamide, and di(2-ethylhexyl) phthalate (DOP).

[0023] The working principle of this invention lies in the sequential synergistic effect of the two-layer structure: incident light (such as the high beam of an oncoming vehicle) first reaches the first PVB layer, where the spectral absorbing material preferentially absorbs the strong light energy in a specific wavelength band (550-750nm); the remaining light, upon transmission and reaching the interface between the two PVB layers, encounters the pseudo-random micro-protrusion scattering structure on the surface of the second PVB layer. This structure further scatters and modulates the light path. This sequence of "spectral absorption filtering first, followed by physical interface scattering" can most effectively disrupt and attenuate the light path that causes glare, thereby achieving highly efficient suppression of glare.

[0024] In this invention, the spectral absorbing material includes at least one of phthalocyanine compounds and vat compounds; based on the weight of PVB resin in the first PVB layer, the content of the spectral absorbing material is 0.002-0.01 wt%.

[0025] Specifically, the phthalocyanine compound may be selected from at least one of copper phthalocyanine (CAS: 147-14-8), iron phthalocyanine (CAS: 132-16-1), and zinc phthalocyanine (CAS: 14320-04-8); the vat compound may be selected from Vat Blue 4 (CAS: 81-77-6). In a preferred embodiment, the spectral absorption material comprises both a phthalocyanine compound and a vat compound, and the mass ratio of the two is 30-80:10-40.

[0026] In this invention, the area coverage of the micro-protrusion scattering structure on the surface of the second PVB layer is 0.1-5%, preferably 0.5-2%. This low coverage design is one of the core elements for balancing anti-glare effect and high light transmittance.

[0027] In this invention, the distribution of the micro-bump scattering structure is generated by a Poisson disk sampling algorithm to ensure pseudo-randomness, and the minimum distance between the centers of any two micro-bumps is not less than 1.5 times the average diameter of the micro-bumps, thereby effectively suppressing optical diffraction. The projected shape of the micro-bumps can be circular, elliptical, or polygonal, with a circular shape being the preferred option.

[0028] In this invention, the average diameter of the micro-protrusions in the micro-protrusion scattering structure is 10-100 μm, preferably 20-50 μm; the average height is 0.5-25 μm, preferably 5-15 μm; and the surface density is 100-5000 per square centimeter, preferably 500-2000 per square centimeter.

[0029] In this invention, the crosslinking polymer material is a radiation-curing resin. Preferably, the radiation-curing resin is an ultraviolet (UV) curing resin. More preferably, the UV curing resin is selected from aliphatic polyurethane acrylate oligomers with a Gardner color value < 1, a refractive index of 1.485-1.495, and a viscosity (26°C) of 110-130 Pa·s.

[0030] In this invention, the absolute value of the difference between the refractive index of the crosslinked polymer material and the refractive index of the PVB matrix material of the second PVB layer is not greater than 0.005, preferably not greater than 0.002, to ensure that the structure achieves optical invisibility after lamination. The PVB matrix material refers to a mixed system composed of PVB resin and additives such as plasticizers, antioxidants, and ultraviolet absorbers.

[0031] In this invention, the micro-protrusion scattering structure is compressed and stably embedded at the interface between two PVB layers after lamination. The compression ratio (defined as the ratio of height H2 after lamination to height H1 before lamination) is 20-80%, preferably 40-60%. Due to the use of cross-linked polymer materials, the structure can maintain the stability of its physical morphology after compression and continue to perform light scattering function.

[0032] In this invention, the thickness ratio of the first PVB layer to the second PVB layer is 1-5:1-5.

[0033] The present invention also provides a method for preparing the PVB interlayer film for anti-glare laminated glass, comprising the following steps: S1. Prepare a first PVB layer containing the spectral absorption material; form the pseudo-randomly distributed micro-protrusion scattering structure on the surface of the second PVB layer through printing and curing processes; S2. The first PVB layer is laminated with a second PVB layer having a micro-protrusion scattering structure, so that the micro-protrusion scattering structure is embedded between the two layers, to obtain the PVB interlayer film for anti-glare laminated glass.

[0034] In this invention, the method for preparing the first PVB layer specifically includes the following steps: (1) Grind the spectral absorption material to an average particle size of 30-60 nm. Take 10-30 parts by weight of the spectral absorption material, 40-80 parts by weight of the alcohol organic solvent and 1-10 parts by weight of the dispersing stabilizer and mix them. Grind and disperse the mixture for 1-3 hours to obtain a stable dispersion with an average particle size of 90-200 nm.

[0035] (2) Take an appropriate amount of the dispersion and mix it with 100 parts by weight of PVB resin, 10-50 parts by weight of plasticizer, 0-1 parts by weight of ultraviolet absorber, 0-1 parts by weight of antioxidant and 0.01-0.2 parts by weight of adhesion modifier. Knead the above mixture at 100-160℃ for 30-60 minutes, and then extrude it using a twin-screw extruder to obtain the first PVB layer.

[0036] In this invention, in step (1), the alcoholic organic solvent may be selected from at least one of methanol, ethanol, propanol, isopropanol, ethylene glycol, and diethylene glycol; the dispersing stabilizer may be selected from acetylacetone.

[0037] In this invention, in step (2), the ultraviolet absorber may be selected from at least one of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole (UV-P), 2-hydroxy-4-methoxybenzophenone (UV-9), 2-hydroxy-4-n-octyloxybenzophenone (UV-531), 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-benzotriazole (UV-320), 2'-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole (UV-326), and 2-(5-chloro-2H-benzotriazole-2-yl)-4,6-bis(1,1-dimethylethyl)phenol (UV-327); the antioxidant may be selected from 2,6-di-tert-butyl-p-cresol (BHT), butylated hydroxyanisole (BHA), and 2,6-di- The adhesive modifier is selected from at least one of the following: tert-butyl-4-ethylphenol, stearyl-β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tridecyl phosphite, tri(tetranyl) phosphite, triphenyl phosphite, trinonylphenyl phosphite, pentaerythritol diphosphite, bis(2,4-di-tert-butyl-6-methylphenyl)ethyl phosphite, 4,4'-butylidene-bis-(3-methyl-6-tert-butylphenol), and 1,1,3-tri-(2-methyl-hydroxy-5-tert-butylphenyl)butane; the adhesive modifier may be selected from at least one of magnesium carboxylate salts and potassium carboxylate salts having 2 to 16 carbon atoms, such as magnesium acetate, potassium acetate, magnesium propionate, potassium propionate, magnesium 2-ethylbutyrate, potassium 2-ethylbutyrate, magnesium 2-ethylhexanoate, and potassium 2-ethylhexanoate.

[0038] In this invention, the method for preparing the second PVB layer with a micro-protrusion scattering structure specifically includes the following steps: (1) Following the preparation method of the first PVB layer, the preparation and addition of the dispersion are omitted to obtain the second PVB layer base film; (2) Prepare a special UV-curable ink, which comprises, by weight: 85-95 parts UV-curable resin, 6-10 parts reactive diluent, and 1-3 parts photoinitiator. Mix all components evenly and degas. (3) Using a ceramic gravure roller designed according to the Poisson disk sampling algorithm, the UV-cured ink is precisely transferred to the preset surface of the second PVB layer base film; by controlling the process parameters, the formed micro-protrusion structure meets the following requirements: area coverage 0.1-5%, average diameter 10-100μm, average height 0.5-25μm, and surface density 100-5000 pieces / square centimeter. (4) Pass the printed film through a UV curing device at 700-900 mJ / cm 2 The ink is cured under irradiation energy to fully cross-link, thereby forming a stable pseudo-random micro-bump scattering structure on the surface of the second PVB layer.

[0039] In this invention, in step (2), the UV-curable resin can be selected from aliphatic polyurethane acrylate oligomers with a Gardner color of <1, a refractive index of 1.485-1.495, and a viscosity (26°C) of 110-130 Pa·s; the reactive diluent can be selected from N-vinylpyrrolidone (CAS No.: 88-12-0); and the photoinitiator can be selected from 2-hydroxy-2-methyl-1-phenyl-1-propanone (CAS No.: 7473-98-5).

[0040] The present invention also provides a laminated glass comprising at least two glass plates and a PVB interlayer film for anti-glare laminated glass disposed between adjacent glass plates.

[0041] 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.

[0042] 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.

[0043] In the comparative examples of the embodiments of the present invention, the relevant information of the raw materials used is as follows: The first PVB resin has a hydroxyl content of 25 mol%, a degree of acetylation of 5 mol%, and a degree of acetalization of 70 mol%; the second PVB resin has a hydroxyl content of 18 mol%, a degree of acetylation of 2 mol%, and a degree of acetalization of 80 mol%.

[0044] The preparation steps for aliphatic polyurethane acrylate oligomers are as follows (parts refer to parts by weight): (1) Add 72.5 parts of dried polytetramethylene ether glycol (PTMEG, number average molecular weight 2000 g / mol, moisture content less than 0.02%) to a dried 500 mL four-necked flask, start stirring (200 r / min), heat to 70 °C, and after PTMEG has completely melted into a transparent liquid, add 18.2 parts of hexamethylene diisocyanate and stir to mix evenly. Then add 0.03 parts of dibutyltin dilaurate catalyst and continue stirring for 10 min. Heat the system to 85 °C and react at a constant temperature for 2 h. During this period, take samples every 30 min and determine the NCO content by di-n-butylamine titration until the NCO mass fraction drops to 2.8% ± 0.1%, thus completing the preparation of the prepolymer.

[0045] (2) Cool the prepolymer to 70°C. Take another 9.3 parts of dried hydroxyethyl acrylate and 0.02 parts of p-hydroxyanisole polymerization inhibitor, mix them evenly in advance, add them to a constant pressure dropping funnel, and add them dropwise to the flask. The dropping rate is controlled at 1 drop / 2 s (about 30 min to complete the dropping), and the temperature of the reaction system is controlled not to exceed 75°C. After the dropping is completed, the reaction is kept at 70°C for 3 h. During this period, the NCO content is measured every 40 min until the NCO content is lower than 0.1%.

[0046] (3) After the reaction was complete, the system was cooled to 50°C, and a vacuum (-0.090 MPa) was turned on. The system was degassed at this temperature for 30 min to remove trace amounts of unreacted small molecule volatiles until no more bubbles were emitted. The vacuum and nitrogen were then turned off, and the product was poured into a dry, sealed plastic container while still hot under a dry environment. The product was then cooled to room temperature until it became a transparent, viscous liquid. The Gardner color of the obtained product was <1, and its viscosity at 26°C was 115 Pa·s.

[0047] Example 1 This embodiment provides a method for preparing a PVB interlayer for anti-glare laminated glass, including the following steps: Preparation of the first PVB layer: The spectral absorbing material (copper phthalocyanine and reduced blue 4, in a mass ratio of 50:10) was ground to an average particle size of 60 nm. 20 parts by weight of the spectral absorbing material, 50 parts by weight of an alcoholic organic solvent (isopropanol), and 3 parts by weight of a dispersing stabilizer (acetylacetone) were mixed. The mixture was ground and dispersed for 1 hour to obtain a stable dispersion with an average particle size of 150 nm.

[0048] Take an appropriate amount of the dispersion and mix it with 100 parts by weight of the first PVB resin, 40 parts by weight of the plasticizer (3GO), 0.2 parts by weight of the ultraviolet absorber (UV-326), 0.2 parts by weight of the antioxidant (BHT), and 0.1 parts by weight of the adhesion modifier (magnesium 2-ethylbutyrate). Based on the weight of the first PVB resin, the content of the spectral absorbing material is 0.0039 wt%. The above mixture is kneaded at 150°C for 40 min, and then extruded using a twin-screw extruder to obtain the first PVB layer, which has a thickness of 0.38 mm.

[0049] Fabrication of a second PVB layer with micro-bump scattering structure: Following the preparation method of the first PVB layer, the preparation and addition of the dispersion were omitted, and the second PVB layer base film was obtained; the thickness of the second PVB layer base film was 0.38 mm.

[0050] A dedicated UV-curable ink was formulated, comprising, by weight: 90 parts of a UV-curable resin (aliphatic polyurethane acrylate oligomer with a refractive index of 1.485, the absolute value of the difference in refractive index between it and the PVB matrix material of the second PVB layer is 0.002), 8 parts of an reactive diluent (N-vinylpyrrolidone), and 2 parts of a photoinitiator (2-hydroxy-2-methyl-1-phenyl-1-propanone). All components were mixed thoroughly and degassed.

[0051] Using a ceramic gravure roller designed based on the Poisson disk sampling algorithm, UV-curable ink is precisely transferred to a preset surface of the second PVB layer base film. By controlling the process parameters, the formed micro-protrusion structure meets the following requirements: a circular projected shape, an area coverage of 1%, a minimum distance between the centers of any two micro-protrusions of 1.6 times the average diameter of the micro-protrusions, an average diameter of 30 μm, an average height of 12 μm, and an area density of 1200 protrusions / cm².

[0052] The printed film is then passed through a UV curing device at 800 mJ / cm². 2 The ink is cured under irradiation energy to fully cross-link, thereby forming a stable pseudo-random micro-bump scattering structure on the surface of the second PVB layer.

[0053] The first PVB layer is laminated with a second PVB layer having a micro-protrusion scattering structure, so that the micro-protrusion scattering structure is embedded between the two layers, with a compression ratio of 58%, to obtain a PVB interlayer film for anti-glare laminated glass.

[0054] Example 2 This embodiment provides a method for preparing a PVB interlayer for anti-glare laminated glass. The difference from Embodiment 1 is that the "first PVB resin" is replaced with the "second PVB resin" (correspondingly, the absolute value of the difference in refractive index between the aliphatic polyurethane acrylate oligomer and the PVB matrix material of the second PVB layer is 0.003), and the "area coverage of the micro-protrusion structure is 4.5%".

[0055] Example 3 This embodiment provides a method for preparing a PVB interlayer for anti-glare laminated glass. The difference from Embodiment 1 is that the "projection shape of the micro-protrusion structure is modified to be elliptical (the ratio of the major axis to the minor axis is 2:1)".

[0056] Example 4 This embodiment provides a method for preparing a PVB interlayer for anti-glare laminated glass, which differs from Embodiment 1 in that the thickness of the first PVB layer is modified to be 0.5 mm and the thickness of the second PVB base film is 0.26 mm.

[0057] Comparative Example 1 This comparative example provides a method for preparing a PVB interlayer for anti-glare laminated glass. The difference from Example 1 is that "no micro-protrusion scattering structure is set on the surface of the second PVB layer", that is, the first PVB layer and the second PVB layer base film are directly laminated to obtain the PVB interlayer for anti-glare laminated glass.

[0058] Comparative Example 2 This comparative example provides a method for preparing a PVB interlayer for anti-glare laminated glass, which differs from Example 1 in that: "when preparing the special UV curing ink, the addition of the photoinitiator in Example 1 is omitted."

[0059] Experimental Example 1 The anti-glare laminated glass samples prepared in Examples 1-4 and Comparative Examples 1-2 were used with PVB interlayer films to prepare laminated glass samples. The specific processes are as follows: The aforementioned intermediate film was placed between two sheets of transparent float glass (300mm long × 300mm wide × 2mm thick) to obtain a laminate. The laminate was placed in a rubber bag and degassed under a vacuum of 2.6 kPa for 20 minutes. Then, while still degassed, it was transferred to an oven and vacuum-pressed at 90°C for 30 minutes to complete the pre-pressing. The pre-pressed laminate was then placed in an autoclave and pressed at 135°C and 1.2 MPa for 20 minutes to obtain laminated glass.

[0060] The above-mentioned laminated glass samples were subjected to performance tests. The specific methods and standards for each test are as follows: (1) Visible light transmittance (Y value of light source A, wavelength 380~780nm) The transmittance of a 50mm×50mm laminated glass in the wavelength range of 300~2500nm was measured using a spectrophotometer, and the transmittance of visible light in the range of 380~780nm was calculated according to the JIS R3211 (1998) standard.

[0061] (2) Haze The haze of laminated glass was measured according to JIS K6714 standard.

[0062] (3) Anti-glare rating A 300mm x 300mm laminated glass pane was placed 500mm from the subject's face, with the line of sight perpendicular to the glass. The subject observed a light source (high-pressure mercury lamp) at a distance of 25m for 5 seconds and evaluated the anti-glare performance. The evaluation used a 9-point scale proposed by De Boer (see Table 1), and the average score of 10 subjects was taken as the test result. All measurements were conducted in a dark room.

[0063] Table 1. 9-point scale standard

[0064] (4) Visibility in the dark (relative scotopic luminance L's and relative photopic luminance Ls) The scotopic luminance L' and photopic luminance L of a 300mm × 300mm laminated glass were measured using a spectroradiometer and a high-pressure mercury lamp. During measurement, the laminated glass was placed vertically at a distance of 500mm from the receiving part of the spectroradiometer along the light-receiving direction, and the light source was placed at a distance of 3500mm from the receiving part. Subsequently, the scotopic luminance L'0 and photopic luminance L0 were measured using the same method without the laminated glass. The photopic luminance was below 0.015 Cd / m² when the light source was off. 2 A dark room.

[0065] The calculation of scotopic luminance L', photopic luminance L, L'0, and L0 adopts the CIE standard relative visibility. Based on the measured values, relative scotopic luminance L's and relative photopic luminance Ls are calculated using the following formulas: Relative scotopic luminance L's = 100 × (scotopic luminance L') / (scotopic luminance L'0); Relative photopic luminance Ls = 100 × (photopic luminance L) / (photopic luminance L0). A higher L's / Ls ratio indicates better anti-glare performance and visibility in the dark.

[0066] The performance test results are recorded in Table 2.

[0067] Table 2 Performance Test Results

[0068] As shown in Table 2, Example 1, as the core example, employs a UV-cured cross-linked polyurethane matrix, demonstrating a good balance between transmittance, haze, and anti-glare performance (L's / Ls and subjective rating), thus verifying the superiority of the present invention. Example 2 shows that increasing the matrix coverage can further enhance the anti-glare effect, but at the cost of reduced transmittance and increased haze. Example 3 proves that, while maintaining a pseudo-random distribution, variations in the specific shape (elliptical) of the matrix are equally effective, illustrating the universality of the present invention. Example 4 shows that, while maintaining the total thickness, adjusting the thickness ratio between the two layers allows the product to maintain excellent performance, demonstrating the structural flexibility of the present invention. All examples (1-4) employing UV-cured cross-linked polyurethane matrices have an L's / Ls ratio ≥ 1.10, significantly higher than the comparative example, proving the good stability and repeatability of the present invention.

[0069] Therefore, this invention organically combines spectral absorption-type and physical structure-type anti-glare technologies to construct a two-layer, in-depth defense system of "absorption first, scattering later." These two mechanisms act sequentially and complement each other in the optical path, resulting in an overall anti-glare effect far exceeding that of a single technology approach. It can effectively suppress glare from strong light while significantly improving visual comfort and safety.

[0070] 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 PVB interlayer for anti-glare laminated glass, characterized in that, Includes a first PVB layer and a second PVB layer stacked together; The first PVB layer contains a spectral absorbing material for selectively absorbing light in the wavelength range of 550-750nm; The second PVB layer has a pseudo-randomly distributed micro-protrusion scattering structure on its surface facing the first PVB layer, and the micro-protrusion scattering structure is composed of a cross-linked polymer material.

2. The PVB interlayer for anti-glare laminated glass according to claim 1, characterized in that, The spectral absorbing material includes at least one of phthalocyanine compounds and vat compounds; the content of the spectral absorbing material is 0.002-0.01 wt% based on the weight of the PVB resin in the first PVB layer.

3. The PVB interlayer for anti-glare laminated glass according to claim 1, characterized in that, The area coverage of the micro-bump scattering structure on the surface of the second PVB layer is 0.1-5%.

4. The PVB interlayer for anti-glare laminated glass according to claim 1, characterized in that, The distribution of the micro-bump scattering structure is generated by the Poisson disk sampling algorithm, and the minimum distance between the centers of any two micro-bumps is not less than 1.5 times the average diameter of the micro-bumps.

5. The PVB interlayer for anti-glare laminated glass according to claim 1, characterized in that, The average diameter of the micro-protrusions in the micro-protrusion scattering structure is 10-100 μm, the average height is 0.5-25 μm, and the surface density is 100-5000 per square centimeter.

6. The PVB interlayer for anti-glare laminated glass according to claim 1, characterized in that, The absolute value of the difference between the refractive index of the crosslinked polymer material and the refractive index of the PVB matrix material of the second PVB layer is not greater than 0.

005.

7. The PVB interlayer for anti-glare laminated glass according to claim 1, characterized in that, The micro-bump scattering structure is compressed after the lamination process, with a compression ratio of 20-80%.

8. The PVB interlayer for anti-glare laminated glass according to claim 1, characterized in that, The thickness ratio of the first PVB layer to the second PVB layer is 1-5:1-5.

9. A method for preparing a PVB interlayer for anti-glare laminated glass according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1. Prepare a first PVB layer containing the spectral absorption material; form the pseudo-randomly distributed micro-protrusion scattering structure on the surface of the second PVB layer through printing and curing processes; S2. The first PVB layer is laminated with a second PVB layer having a micro-protrusion scattering structure to obtain the PVB interlayer film for anti-glare laminated glass.

10. A laminated glass, characterized in that, It includes at least two glass plates and a PVB interlayer for anti-glare laminated glass as described in any one of claims 1 to 8, placed between adjacent glass plates.

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