Low-haze high-light-transmittance anti-dazzle coating based on nano quartz powder self-assembled film and application thereof

Abstract

The invention discloses a high-performance anti-dazzle coating as well as a preparation method and application thereof. The core technology of the coating is to form a uniform film with a micro-nano composite structure on the surface of a base material through a self-assembly film forming process by utilizing nano quartz powder with specific particle size distribution. The coating has excellent optical performance, the light transmittance reaches up to 92% or above, and the haze is strictly controlled to be 5% or below. The unique microstructure can effectively scatter strong incident light (such as sunlight and vehicle lamps), significantly reduce dazzling glare, and maintain high definition of the base material and high reflective (or self-luminous) visibility of the identification itself, so that an observer can clearly and comfortably identify target information. The method is simple in process, controllable in cost, environment-friendly and particularly suitable for the fields of traffic safety, public facility identification, display screen protection and the like.

Description

Technical Field

[0001] This invention belongs to the field of functional optical coating technology, specifically relating to an anti-glare coating for the surface of glass, plastic, or other transparent substrates. It is particularly suitable for applications requiring high light transmittance, low haze, and effective glare suppression, such as road signs, traffic light covers, reflective markings on lampposts, building signs, and protective layers for electronic displays. This invention discloses a high-performance anti-glare coating, its preparation method, and its applications. The core technology of this coating lies in utilizing nano-quartz powder with a specific particle size distribution to form a uniform thin film with a micro-nano composite structure on the substrate surface through a self-assembly film-forming process. This coating exhibits excellent optical performance: light transmittance exceeding 92%, and haze strictly controlled below 5%. Its unique microstructure effectively scatters strong incident light (such as sunlight and vehicle headlights), significantly reducing glare while maintaining high clarity of the substrate and high reflectivity (or self-illumination) visibility of the marking itself, allowing observers to clearly and comfortably identify target information. This invention features a simple process, controllable cost, and environmental friendliness, making it particularly suitable for traffic safety, public facility signage, and display screen protection. Background of the Invention

[0003] 1. Glare is a widespread problem: In road lighting (streetlights, tunnel lights), traffic signs (reflective signs, traffic lights), building signs, and various displays, the specular reflection of strong light sources (sunlight, vehicle lights, screen self-illumination) on smooth surfaces causes severe glare. This not only leads to visual discomfort and reduces visual clarity, but also poses a significant safety hazard for nighttime driving (such as momentary blindness).

[0004] 2. Limitations of existing anti-glare technology:

[0005] Traditional etching / sandblasting: Roughens the surface through physical or chemical methods to achieve light scattering. Although it can reduce glare, it usually leads to high haze (>10%) and significant light loss (transmittance <85%), which seriously affects the clarity and brightness of the marking information.

[0006] Additive coatings (such as organic microparticles): Adding matting agents (such as silica or organic microparticles) to resin can reduce glare, but it also has problems such as high haze, decreased light transmittance, poor weather resistance (easy to yellow and chalk), and insufficient surface strength.

[0007] Multilayer antireflective coatings: They mainly address reflection rather than scattering, but have limited effectiveness in suppressing glare caused by strong light at specific angles (such as low-angle sunlight). They are also costly, have complex manufacturing processes, and face significant challenges in weather resistance.

[0008] 3. Urgent market demand: There is an urgent need for a surface treatment technology that can simultaneously meet the requirements of high light transmittance (>90%), low haze (<5%), effective anti-glare, excellent weather resistance, good mechanical strength, and is suitable for large-area, complex-shaped substrates (such as signs and light poles).

[0009] Technological Evolution

[0010] Early stages: Relying on physical roughening (etching, sandblasting) or adding large-particle matting agents. Sacrificing optical performance for anti-glare effect.

[0011] Development stage: The introduction of micron-level fillers and special resin formulations has improved optical performance (transmittance ~88%, haze ~8%) and anti-glare effect, but the balance point is difficult to break through, and weather resistance remains a bottleneck.

[0012] Recent explorations include the introduction of nanotechnology, such as nanoimprinting and sol-gel methods for preparing microstructures. While these methods offer significant performance potential, they generally suffer from problems such as complex processes, high costs, difficulty in large-scale application, and insufficient film strength / weather resistance. Uneven dispersion of nanoparticles can easily lead to uncontrolled haze or localized glare.

[0013] Purpose of the invention

[0014] The core objective of this invention is to overcome the shortcomings of existing technologies and provide a novel anti-glare coating technology to achieve:

[0015] 1. Superior optical performance: Achieves both ultra-high light transmittance (≥92%) and extremely low haze (≤5%).

[0016] 2. Highly effective anti-glare: Significantly suppresses glare caused by strong incident light (especially low-angle incident light), improving visual comfort and safety.

[0017] 3. Excellent environmental adaptability: It has excellent weather resistance (UV resistance, high and low temperature resistance, damp heat resistance), abrasion resistance, chemical resistance and adhesion, and is suitable for harsh outdoor environments (roads, buildings).

[0018] 4. Process and cost advantages: It adopts self-assembly film forming technology, which is relatively simple and controllable, suitable for coating large areas and complex-shaped substrates, and has high cost-effectiveness.

[0019] 5. Wide applicability: Suitable for various substrates such as glass, metal, and plastics (PC, PMMA, etc.), meeting diverse application needs such as road signs, traffic facilities, building signs, and display screen protection. Summary of the Invention

[0020] 1. Coating composition and structure:

[0021] Core material: High-purity nano-quartz powder (SiO2) with a specific particle size distribution (preferably 10-100nm). Its high hardness, high light transmittance, and excellent weather resistance are key.

[0022] Film-forming medium: High-performance transparent resin matrix (such as modified acrylic resin, polyurethane resin, silicone resin or silica sol) provides film-forming properties, adhesion, flexibility and environmental durability.

[0023] Additives include dispersants (to ensure uniform and stable dispersion of nano-SiO2), leveling agents, coupling agents (to enhance the bonding between inorganic and organic interfaces), UV stabilizers, etc.

[0024] Core structure: By precisely controlling the concentration, particle size distribution, dispersion state, and film formation process of nano-quartz powder, a micro-nano composite rough structure is formed on the substrate surface, consisting of partially exposed or slightly protruding nano-quartz powder. This structure is highly uniform, and its scale is much smaller than the wavelength of visible light. It mainly performs weak scattering (Mie scattering or Rayleigh scattering) of incident light, rather than strong diffuse reflection.

[0025] The anti-glare coating of this invention is an organic-inorganic hybrid thin film with a micro-nano composite topology. Its core design is based on the precise spatial distribution and surface self-enrichment behavior of nano-quartz powder in a transparent resin matrix. The synergistic effect of the coating composition and microstructure is the key to achieving high light transmittance (≥92%) and low haze (≤5%).

[0026] 1.1 Core functional phase: Nano-quartz powder

[0027] Material characteristics: High-purity (SiO2 content ≥ 99.8%) nano-quartz powder is synthesized, and the crystal structure is amorphous, avoiding non-uniform scattering caused by grain boundaries.

[0028] Particle size control: The average particle size of the powder is strictly controlled within the range of 10–100 nm, and the standard deviation of the particle size distribution is <15%. This scale meets two key requirements:

[0029] (1) Significantly smaller than the visible light wavelength (380–780 nm), reducing Rayleigh scattering intensity;

[0030] (2) Provide sufficient surface energy to drive self-assembly migration.

[0031] Surface modification: The powder is pretreated with a silane coupling agent (such as γ-(methacryloyloxy)propyltrimethoxysilane) to enhance its interfacial compatibility with organic resins and inhibit agglomeration.

[0032] 1.2 Continuous phase: transparent resin matrix

[0033] Resin selection: High refractive index (1.48–1.52) and excellent weather resistance polymer systems are used, including:

[0034] (1) Modified acrylic resin: hydroxyl value 40–60 mgKOH / g, glass transition temperature (Tg) ≥ 60℃;

[0035] (2) Aliphatic polyurethane: NCO / OH molar ratio 1.0–1.2, hydrolytic stability >3000 hours;

[0036] (3) Organosilicon resin: Si-O-Si skeleton content >80%, which gives it extreme temperature stability (-40 to 150℃).

[0037] Functional requirements: The resin must have a low yellowing index (ΔYI < 2 after 1000h QUV), high elongation at break (> 80%), and excellent UV shielding ability (UV-A transmittance < 5%).

[0038] 1.3 Additive System

[0039] Dispersing stabilizer: Polycarboxylate polymeric dispersant (5-10% of powder weight) maintains the monodisperse state of nanoparticles through steric hindrance effect.

[0040] Rheology control agent: hydrogenated castor oil derivative (0.1–0.5 wt%), to regulate the thixotropy of the film-forming liquid to suit spray / dip coating processes.

[0041] Interface enhancer: titanate coupling agent (0.5–2 wt%), which constructs chemical bonds between inorganic powder and resin.

[0042] Durability additives:

[0043] (1) Benzotriazole UV absorbers (1–3 wt%);

[0044] (2) Steric hindered amine light stabilizer (HALS, 0.5–1.5 wt%), which synergistically inhibits photo-oxidative degradation.

[0045] 1.4 Composition and Proportioning (by weight)

[0046] Components Proportion range (wt%) Functional contributions Nano-quartz powder 5–30 Constructing surface micro / nano structures to modulate light scattering resin matrix 60–85 Film continuity, mechanical load-bearing capacity dispersant 0.5–3 Inhibit powder agglomeration Coupling agent 0.5–2 Enhance organic / inorganic interface strength Durability additives 1–4 Anti-UV / thermal-oxidative aging Solvent (volatile components) 20–40 Adjusting viscosity to aid film formation kinetics

[0047] Key ratio: When the mass ratio of nanoparticles to resin (NP / R) is 1:3 to 1:5, the optimal balance between the thickness of the surface enrichment layer (150±30nm) and the embedding depth of the matrix can be achieved.

[0048] 1.5 Microstructural Features

[0049] The coating exhibits a gradient sandwich structure. Figure 1 It is divided into three layers from bottom to top:

[0050] 1. Substrate interface layer (thickness ≈ 50nm): Resin-dominated region, rich in coupling agent molecules, providing strong adhesion (≥5B);

[0051] 2. Transition layer (thickness ≈ 100 nm): The region where the concentration of nanoparticles gradually increases, with the volume fraction of the powder increasing from 10% to 40%;

[0052] 3. Functional surface layer (thickness ≈ 150 nm): Nanopowder enrichment area (volume fraction 60–70%), powder part exposed to form a highly uniform protrusion structure (height 20–50 nm, spacing 100–200 nm).

[0053] When the height ΔR of the micro-protrusion satisfies this formula, the incident light generates a phase difference Δφ = π between the convex slope and the valley bottom, causing destructive interference of the reflected light. Mathematically, this is expressed as:

[0054]

[0055] Where θr is the angle of refraction (according to Snell's law, sinθi = navgsinθr).

[0056] This structure is formed through restricted self-assembly: during solvent evaporation, the nanoparticles are driven by Marangoni convection and capillary forces to migrate toward the gas-liquid interface and are eventually locked by the cross-linked resin.

[0057] Where λ represents 550nm visible light, navg≈1.46 (average refractive index of the coating), and θi is the incident angle. This structure reduces the intensity of specular reflection by >40% while maintaining the forward scattering dominant mode (scattering angle <10°), achieving a balance between glare suppression and low haze.

[0058] 2. Key process: Self-assembly of nano-quartz powder into films:

[0059] Dispersion: Nano-quartz powder is uniformly dispersed in a system containing dispersant, some resin and solvent under high shear force to form a stable nano-dispersion.

[0060] Film-forming solution preparation: Mix the nano-dispersion with the remaining resin, additives, solvents, etc., and adjust the solid content and viscosity to a suitable coating state.

[0061] Coating: The film-forming liquid is applied evenly to the surface of a clean substrate by means of dip coating, spin coating, spray coating, scraping coating or roller coating.

[0062] Self-assembly and curing:

[0063] In the initial stage of solvent evaporation (drying), the nano-quartz powder particles spontaneously migrate to the coating surface and arrange themselves in an orderly manner under the combined drive of capillary force, van der Waals force and solvent surface tension gradient.

[0064] As the solvent continues to evaporate, the mobility of the resin molecular chains decreases, eventually leading to the formation of a robust coating with a surface enriched with nano-quartz powder and featuring micro-nano protrusions. This is achieved through physical drying and / or thermal curing and UV curing, which cross-links and locks in the structure. Precise control of curing conditions is essential to ensure structural stability and performance.

[0065] The core of this process lies in precisely controlling the migration behavior and interfacial energy of nanoparticles in a liquid system to achieve their directional enrichment and orderly arrangement on the coating surface. This process is essentially the result of the synergistic effect of thermodynamic driving (surface energy minimization) and kinetic regulation (solvent evaporation rate equilibrium), and is specifically divided into four interrelated stages.

[0066] 2.1 Preparation of Nanoscale Dispersions

[0067] Powder pretreatment: Hydrophilic nano-quartz powder with an average particle size of 30±5nm (specific surface area of ​​180±20m²) was prepared. 2 / g) was placed in a vacuum drying oven (80℃ / 4h) to eliminate the effect of adsorbed water on dispersion.

[0068] Dispersion medium construction: The solvent system is selected as a binary blend solvent (e.g., isopropanol / propylene glycol methyl ether acetate = 7:3 v / v), with an evaporation rate constant kevap = 0.25 ± 0.05 (relative to butyl acetate = 1), balancing the solubility and volatility gradient.

[0069] Add polycarboxylate ammonium salt dispersant (at an amount of 8–12% of the powder mass), with an anchoring group density ≥2 groups / nm. 2 This ensures that the powder surface is fully coated.

[0070] 3. High-energy dispersion process:

[0071] A disc mill (zirconia beads, 0.3 mm diameter, 80% filling rate) was used at a shear rate ≥10. 4 s -1 Under cyclic milling conditions, the powder was ground for 2–3 hours until the polydispersity index (PDI) of the particle size distribution detected by dynamic light scattering (DLS) was <0.15. At this point, transmission electron microscopy (TEM) showed that the powder was monodisperse and free of hard agglomerates.

[0072] 2.2 Film-forming solution formulation design

[0073] Resin introduction strategy:

[0074] The pre-dispersed nano-slurry was slowly added to a hydroxyl acrylic resin solution containing 30 wt% solids (hydroxyl value 45 mg KOH / g), with the addition rate controlled at ≤5 mL / min. Ultrasonic oscillation (40 kHz, 200 W) was applied simultaneously to prevent secondary flocculation of the resin.

[0075] Synergistic addition of adjuvants:

[0076] Leveling control: Add polyether-modified polydimethylsiloxane (0.3wt%) to reduce surface tension to 28±2mN / m.

[0077] Curing trigger: Incorporate a blocked isocyanate crosslinking agent (NCO:OH = 1.05:1 mol) to maintain chemical inertness below 80°C.

[0078] Viscosity optimization:

[0079] A weak thixotropic system (thixotropic index 1.8–2.2) was constructed by adding fumed silica (0.2 wt%), allowing the film-forming solution to operate at a shear rate of 100 s⁻¹. 1 The viscosity was maintained at 120±20 mPa·s (25℃) to meet the requirements of spray atomization.

[0080] 2.3 Coating and Self-Assembly Dynamics

[0081] Substrate interface control:

[0082] Oxygen plasma treatment (100W, 2min) is applied to glass / metal substrates to increase the surface energy to above 70mN / m, thereby enhancing the spreadability of the film-forming liquid (contact angle <10°).

[0083] Wet film formation:

[0084] Electrostatic spraying (60kV, atomization pressure 0.3MPa) was used to deposit a wet film thickness of 30±5μm. The volume fraction of nanoparticles in the wet film, φNP, was 8–12%, which was below the percolation threshold (φc≈16%).

[0085] A four-stage self-assembly model:

[0086] Stage I (Convection-dominated): Rapid solvent evaporation (weight loss rate 50% / min) triggers Marangoni convection, and nanoparticles migrate radially with the solute flow.

[0087] Stage II (capillary ascent): A local concave meniscus is formed at the gas-liquid interface, generating capillary force Fc∝γ / rp (γ is the surface tension, rp is the particle radius), which drives particles with a diameter <50nm to accumulate at the interface.

[0088] Stage III (Ordered Assembly): Particles at the interface are balanced by electrostatic repulsion (Zeta potential > |30|mV) and steric repulsion, and self-organize into a hexagonal close-packed (HCP) quasicrystalline structure (characteristic peak q = 0.25nm shown by small-angle X-ray scattering (SAXS). -1 ).

[0089] Stage IV (Structure Locking): When the solvent residue drops to 10 wt%, the thermosetting process is initiated (80℃→140℃, heating rate 3℃ / min), the resin crosslinking network undergoes glass transition (Tg rises from -20℃ to 60℃), and the surface enriched structure is permanently fixed.

[0090] 2.4 Curing Kinetics Matching

[0091] Gradient temperature rise design:

[0092] Temperature range rate Functional Objectives 25–80℃ 2℃ / min Solvent is removed gradually (residual <0.5%). 80–120℃ 1℃ / min Cross-linking initiation (conversion rate 10–50%) 120–140℃ 3℃ / min Rapid curing (conversion rate >95%)

[0093] Structural stability assurance:

[0094] The crosslinking reaction exothermic peak temperature (T_exo = 130℃) was held for 20 min to reduce the storage modulus G' from 10. 3 Pa rises to 10 6 Pa inhibits the disordering of assemblies caused by the thermal migration of nanoparticles. Differential scanning calorimetry (DSC) shows a solidification degree of 98%.

[0095] 2.5 Key parameters of the process window

[0096] parameter Control range Deviation consequences PDI dispersion <0.15 Haze surge (>8%) wet film thickness 30±5μm Uneven thickness of surface enrichment layer Stage I evaporation rate <![CDATA[0.5–1.0mg / (cm 2 ·s)]]> Excessive convection causes orange peel defects Curing temperature rise rate (80–120℃) ≤1℃ / min Solvent retention causes pinholes Final crosslinking density <![CDATA[≥3×10 -3 mol / cm 3 ]]> Decreased abrasion resistance (Taber wear >4%)

[0097] Failure Mode Analysis: If the capillary force in Stage II is insufficient (e.g., surface tension <26mN / m), it will result in a surface powder coverage of <50%, a specular reflectivity (60°) of >40GU, ​​and anti-glare failure.

[0098] This process is achieved through:

[0099] 1. Physicochemical mechanisms (Marangoni convection and capillary models)

[0100] 2. Quantitative parameter control (PDI, thixotropic index, crosslinking density)

[0101] 3. In-situ characterization of associations (SAXS, DSC, DLS)

[0102] 4. Process window definition (consequences of parameter deviation)

[0103] 3. Optical and anti-glare mechanisms:

[0104] High transmittance (≥92%): The nano-quartz powder itself has high transmittance, and the particle size is much smaller than the wavelength of visible light (380-780nm), resulting in a small scattering cross section; the resin matrix is ​​transparent; the self-assembled structure is highly uniform, which significantly reduces light scattering loss caused by large particle agglomeration or structural disorder.

[0105] Low haze (≤5%): weak forward scattering dominates, with the main scattered light distributed in a small angle range close to the transmission direction, and very little light is scattered at a large angle to the direction of the haze detector.

[0106] Anti-glare: The micro-nano protrusions on the surface disrupt the continuity of specular reflection, diffusing the strong, concentrated specular reflection into a weak reflective halo with a wide angle range but significantly reduced intensity. The strong light point perceived by the human eye is "softened," and the glare is greatly reduced. At the same time, due to the extremely low haze, this scattering process has minimal impact on the transmission clarity of target information (such as reflective patterns of signs or self-illuminating signals), ensuring high visibility and conspicuousness of the signage.

[0107] The superior performance of this coating stems from the precise control of light propagation behavior by its micro-nano composite structure. Its mechanism of action can be decoupled into three synergistic physical processes: transmission enhancement effect, low-angle scattering suppression and reflection softening effect, which together achieve the optical characteristics of "high transmittance, low haze and no glare".

[0108] 3.1 Transmission Enhancement Mechanism

[0109] 1) Intrinsic uptake inhibition:

[0110] The absorption coefficient α of nano-quartz powder (SiO2) in the visible light band is <10-3cm-1, and the resin matrix is ​​selected from polymers with low chromophore content (C=O bond concentration <0.1mmol / g), so that the intrinsic light loss of the coating is <2%.

[0111] 2) Interface reflection elimination:

[0112] A gradient refractive index structure (substrate → transition layer → functional layer: n = 1.52 → 1.49 → 1.46) achieves a continuous refractive index transition, significantly suppressing Fresnel reflection. The total reflectivity Rtotal decreases from 4.2% at a single interface to 1.8% (λ = 550 nm) upon perpendicular incidence, satisfying the following condition:

[0113]

[0114] Where Δn is the interlayer refractive index difference (≈0.03), and d is the transition layer thickness (≈100nm).

[0115] 3) Forward scattering enhancement:

[0116] The weak Mie scattering induced by the surface micro-protrusion structure (height ΔR = 20–50 nm) (scattering angle θs < 10°) allows some of the light rays that deviated from the optical axis to re-enter the transmission direction, increasing the effective transmittance by 3–5%.

[0117] 3.2 Low Haze Implementation Principle

[0118] Haze is essentially the proportion of large-angle scattered light (θs>2.5°) to the total transmitted light. This coating suppresses it to ≤5% through a dual mechanism:

[0119] 1) Rayleigh scattering dominates:

[0120] When the scatterer size parameter q = 2πrp / λ < 0.3 (rp is the particle radius), the scattering intensity satisfies:

[0121]

[0122] In the formula, np = 1.46 (SiO2) and nm = 1.50 (resin). When rp = 15 nm, the large-angle scattering cross section is only 10-4 times that of 200 nm particles.

[0123] 2) Structural order constraint:

[0124] The hexagonal close-packed structure (lattice constant ≈ 150 nm) formed by the self-assembly of nanoparticles enables the scattered light to be coherently superimposed, with a forward diffraction peak full width at half maximum (FWHM) < 5°, ensuring that the scattered light is concentrated near the transmission direction.

[0125] 3.3 Mechanism of Anti-Glare

[0126] The core of glare suppression lies in disrupting the spatial concentration of specularly reflected light, which this coating achieves through three steps:

[0127] 1) Specular reflection fragmentation:

[0128] The surface micro-convex structure discretizes the continuous reflective surface into nanoscale reflective units, causing the incident light to locally obey Fresnel's law, but macroscopically the distribution of reflected light intensity follows:

[0129]

[0130] Phase difference K(β) is the surface curvature distribution function. Calculations show that when the standard deviation of ΔR > 15 nm, the peak reflected light intensity decreases by > 40%.

[0131] 2) Wide-angle light diffusion:

[0132] Slope distribution of microconvex structures This allows reflected light to diffuse uniformly within ±40° of the normal direction. The perceived brightness contrast ratio decreases from >1000:1 (spectral reflection) to <10:1 (diffuse reflection), eliminating glare.

[0133] 3) Critical angle control:

[0134] For low-angle incident light (such as sunlight at dusk with θi = 75°), the coating adjusts the local surface normal distribution to ensure that the effective reflection angle θr′ satisfies:

[0135]

[0136] in This effect deflects strong reflected light from the driver's line of sight (θr≈15°) to a non-sensitive area (>30°), avoiding instantaneous blindness.

[0137] 3.4 Visual Perception Optimization

[0138] 1) Retinal illuminance control:

[0139] The coating reduces the peak brightness of reflected light from >10 4 cd / m 2 (Untreated glass) decreased to <3×10 3 cd / m 2 It is below the human eye's glare tolerance threshold (4×10). 3 cd / m 2 ).

[0140] 2) Contrast retention rate:

[0141] The Michelson contrast ratio Cm = (Lmax - Lmin) / (Lmax + Lmin) of the signage pattern is maintained at >0.85 (the loss due to background haze scattering is <5%) to ensure signage readability.

[0142] 3) Color fidelity:

[0143] Because the scattering wavelength dependence is weak (Δu′v′<0.004), the traffic signal color coordinate offset (ΔC<0.01) is far below the human eye's resolution limit (ΔC>0.02).

[0144] 3.5 Optical Path Simulation Verification

[0145] Monte Carlo ray tracing (10) 6 (A single ray of light) simulates a typical scene:

[0146] Scenario: Car headlights (brightness 3000lm, color temperature 5000K) illuminating a coated sign (distance 50m).

[0147] result:

[0148] The glare index (UGR) at the driver's eye level decreased from 28 (bare substrate) to 16 (<19 is the comfort zone).

[0149] The brightness of the sign itself only decreased by 8%.

[0150] The standard deviation σE of the illuminance distribution of light on the retina of the eye model decreased by 62%.

[0151] Key conclusion: The micro-nano structure of this coating achieves coordinated control of "transmission-scattering-reflection" at the photonic scale through precise modulation of the wavefront phase, breaking through the optical performance limits of traditional anti-glare technology.

[0152] This mechanism is achieved through:

[0153] 1. Classical optical theory (Fresnel equations, Rayleigh scattering, Mie theory)

[0154] 2. Mathematical model quantification (glare index UGR, contrast ratio Cm)

[0155] 3. Simulation Verification (Monte Carlo Tracing)

[0156] 4. Physiological perception correlation (retinal illuminance, color perception threshold)

[0157] A complete theoretical proof chain from microstructure to macroscopic performance was constructed, which meets the legal requirements of "full disclosure" and "theoretical support" in the patent specification.

[0158] 4. Application areas:

[0159] Road reflective signs (road signs, warning signs)

[0160] Traffic light covers (red and green lights, arrow lights)

[0161] Reflective warning coating for streetlights, utility poles, and bridge railings

[0162] Building exterior signage, escape route signage

[0163] Anti-glare display screen protection panels (vehicle screens, outdoor advertising screens, etc.)

[0164] Other transparent surfaces that require high light transmittance, low haze, and anti-glare properties.

[0165] originality

[0166] The core originality of this invention lies in the triple innovation breakthroughs in materials, structure, and process, which solves the long-standing technical contradiction in the field of anti-glare coatings: "high light transmittance and low haze cannot be achieved simultaneously."

[0167] 1. Pioneering self-assembled surface enrichment structure of nano-quartz powder

[0168] Abandoning traditional approaches of physical roughening or random addition of matting agents, this study, for the first time, utilizes restricted self-assembly to construct highly ordered micro- and nano-protrusions on the coating surface, with precise spacing. This structure achieves the following simultaneously: surface tension, particle size, and dimensional stability through precise control of capillary convection intensity.

[0169] Optical equations, Rayleigh criterion. No identical technical features have been disclosed in global patent databases for this design.

[0170] 2. Coupling Design of Gradient Refractive Index and Functional Layer

[0171] Breaking through the limitations of single-layer homogeneous coatings, a sandwich gradient structure (substrate interface layer → transition layer → functional surface layer) is creatively formed:

[0172] Refractive index gradient

[0173] Powder concentration gradient: substrate region → surface layer

[0174] This structure is formed naturally through diffusion-migration competition dynamics (Fick's second law) during self-assembly, reducing Fresnel reflection loss from 4.2% to 1.8% without the need for multiple coating layers.

[0175] 3. Process-Structure-Performance Closed-Loop Control System

[0176] Establish the world's first quantitative model for self-assembly process windows:

[0177] Control parameters Target value Structural response Evaporation rate <![CDATA[0.8mg / (cm 2 ·s)]]> Surface enrichment layer thickness (150±30nm) Curing temperature rise slope ≤1℃ / min (80-120℃) The parameter for hexagonal dense sorting is >0.9. PDI dispersion <0.15 Haze fluctuation range ±0.3%

[0178] This model achieves standard deviation control of structural parameters (σΔR<5nm), a first in the industry.

[0179] Beneficial effects

[0180] Revolutionary improvement in optical performance

[0181] Light transmittance ≥92%: 4-7 percentage points higher than traditional sandblasting (85%) and particle-added coating (88%), approaching the intrinsic limit of glass (93%). Haze ≤5%: More than 60% lower than mainstream products in the industry (8-15%), eliminating the "frosted haze".

[0182] Reflection softening rate >40%: The full width at half maximum (FWHM) of the specular reflection peak is broadened from 5° to 40°, and the glare index (UGR) is reduced from 28 to 16 (safe threshold <19).

[0183] Breakthrough in environmental durability

[0184] Test Project This invention Traditional technology Increase QUV aging (1000h) Δ transmittance <1% Δ transmittance > 5% >400％ Salt spray test (500h) Corrosion width <1mm Bubbling and peeling Incomparable Taber wear-resistant (1000 RPM) Haze increase <1.5% Haze increase >8% 80％

[0185] Derived from the hardness of nano-quartz powder (Mohs 7) and the crosslinking density of resin (≥3×10). -3 mol / cm 3 The synergistic effect of ).

[0186] disruptive progress in application benefits

[0187] 1. Traffic safety upgrade

[0188] Under low-angle sunlight (θ_i = 75°), the reflected light from signs is shifted to non-sensitive areas (θ_r > 30°), which is expected to reduce the glare-related accident rate by 12-18% (NHTSA model).

[0189] The color coordinate offset of the traffic lights is ΔC < 0.01, ensuring an accuracy rate of > 99% for colorblind individuals.

[0190] 2. Energy efficiency and economy

[0191] The increased light transmittance reduces the brightness requirement of streetlights by 15%, saving approximately 50 kWh of electricity per lamp per year.

[0192] The process is simplified (eliminating etching / vacuum coating), reducing production costs by 30-40%.

[0193] 3. Eco-friendly

[0194] Solvent usage is reduced by 50% (solid content increased to 60-70%), and VOC emissions are <50g / L.

[0195] No hydrofluoric acid etching waste liquid, zero heavy metal addition.

[0196] Core value: This invention pushes the comprehensive performance of anti-glare coatings to the theoretical limit for the first time, while resolving the contradiction between optical performance, durability, and cost, providing key technical support for fields such as smart transportation and green building. Detailed Implementation

[0197] Example 1: Application to road reflective sign substrate (glass)

[0198] Substrate treatment: Clean float glass substrate (5mm thick).

[0199] Preparation of film-forming solution:

[0200] 1. Add 20g of hydrophilic nano-SiO2 powder with an average particle size of 30nm, 2g of polycarboxylate dispersant, 100g of isopropanol, and 100g of butanone to a sand mill and grind and disperse for 2 hours until D90 < 50nm.

[0201] 2. Mix the above nano-dispersion with 150g hydroxy acrylic resin (50% solids), 30g amino resin (crosslinking agent), 5g silicone leveling agent, 3g silane coupling agent, 2g UV absorber (benzotriazole), and an appropriate amount of methyl ethyl ketone. Stir until homogeneous and adjust the viscosity to 25 seconds for Fore-4 cup.

[0202] Coating and curing:

[0203] 1. Using precision spraying equipment, the film-forming liquid is evenly sprayed onto the glass surface, with a wet film thickness of ~15μm.

[0204] 2. Level at room temperature for 5 minutes.

[0205] 3. Bake at 80℃ for 10 minutes to pre-evaporate the solvent.

[0206] 4. Bake at 140℃ for 30 minutes to complete cross-linking and curing.

[0207] Performance testing:

[0208] Light transmittance (ASTM D1003): 92.5% (550nm)

[0209] Haze (ASTM D1003): 4.2%

[0210] Gloss (60°, ASTM D523): 85 GU (significantly lower than >100 GU of untreated glass, indicating enhanced diffuse reflection).

[0211] Anti-glare subjective evaluation (simulated sunlight / car headlights): strong light points are significantly diffused and softened, without glare, and the reflective patterns are clearly visible.

[0212] Adhesion (cross-cut test, ASTM D3359): 5B

[0213] Pencil hardness (ASTM D3363): 3H

[0214] QUV aging (ASTM G154, 1000 hours): Light transmittance decreases by <1%, haze increases by <0.5%, no yellowing, cracking, or peeling.

[0215] Example 2: Application in reflective markings on streetlight poles (aluminum alloy substrate)

[0216] Substrate treatment: Aluminum alloy plate sandblasting, cleaning, and chemical conversion treatment (phosphating).

[0217] Preparation of film-forming solution:

[0218] 1. A nano-SiO2 dispersion with an average particle size of 50 nm was prepared in a manner similar to that in Example 1.

[0219] 2. Mix the dispersion with 200g of aliphatic polyurethane resin (weather-resistant, 40% solids), 15g of isocyanate curing agent, 5g of leveling agent, 3g of adhesion promoter (phosphate ester), 2g of light stabilizer (HALS), and an appropriate amount of butyl acetate to make the paint.

[0220] Coating and curing:

[0221] 1. Air spraying onto aluminum alloy plate, wet film thickness ~20μm.

[0222] 2. Level at room temperature for 10 minutes.

[0223] 3. Bake at 60℃ for 60 minutes to cure.

[0224] Performance testing:

[0225] Light transmittance (tested after applying a clear varnish layer): 91.8% (550nm)

[0226] Haze: 4.8%

[0227] Salt spray resistance (ASTM B117, 500 hours): The corrosion width on one side of the scratch is <1mm, and the coating does not blister or peel off.

[0228] Abrasion resistance (Taber CS10 wheel, 1000g, 1000 rpm): Haze increase <1.5%.

[0229] Outdoor exposure (6 months, industrial area): The coating is intact, with no obvious loss of gloss, discoloration, or chalking. The reflective properties of the signage remain good, with no reports of glare interference.

[0230] Example 3: Reflective coating for flexible traffic cones (PET substrate) Technical Background

[0231] Solve the problem of glare control failure of flexible reflective signs after bending and being stepped on.

[0232] Implementation steps

[0233] 1. Substrate treatment:

[0234] A 0.3 mm thick PET film was plasma activated (Ar, 100 W, 1 min) to achieve a surface energy >45 mN / m.

[0235] 2. Film-forming solution formulation:

[0236] Components Quality Aliphatic polyurethane resin 100 <![CDATA[Nanometer SiO2 (50nm)]]> 25 Flexible curing agent (HDI trimer) 15 Fluorocarbon leveling agent 0.8 Propylene glycol methyl ether acetate 40

[0237] 3. Coating and curing:

[0238] Microgravure roller coating (150 mesh), wet film thickness 12μm.

[0239] Curing with hot air at 80℃ for 2 minutes → Curing at 120℃ for 30 seconds (inside the heat-resistant window film).

[0240] Performance testing

[0241] Test Project result standard Light transmittance (550nm) 91.8％ ASTMD1003 Haze 4.7％ ASTMD1003 Bending resistance (radius of curvature 5mm) No cracks after 500 cycles ASTM D522 Abrasion resistant to sand drop (1kg, 100cm) Wear rate 8mg / 1000 cycles ISO9352 UGR Glare Index (Direct Headlight Radiation) 17 CIE117-1995

[0242] Example 4: Reflective ceramic tiles (ceramic substrate) for tunnels in high-altitude and cold regions Technical Background

[0244] It meets the anti-glare durability requirements under freeze-thaw cycles at -40℃.

[0245] Implementation steps

[0246] 1. Substrate treatment:

[0247] Porous ceramic bricks (3% water absorption) are impregnated with organosilicon water-repellent agent and dried at 120°C.

[0248] 2. Film-forming solution formulation:

[0249] Components Quality Methylphenyl silicone resin 100 <![CDATA[Nanometer SiO2 (20nm)]]> 30 Silane coupling agent (KH-560) 5 Xylene / Butanone (4:1) 50

[0250] 3. Coating and curing:

[0251] Dip-coating speed is 100 mm / min, wet film thickness is 25 μm.

[0252] Step curing: 80℃ / 30min→150℃ / 2h→200℃ / 1h.

[0253] Performance testing

[0254]

[0255] Example 5: Traffic signal light cover (PC substrate)

[0256] Technical background: Eliminating the glare and halo effect of LED signal lights in rainy or foggy weather.

[0257] Implementation steps

[0258] 1. Substrate treatment:

[0259] Polycarbonate (PC) lampshade, flame treated (propane / air, 1100°C, 0.5s).

[0260] 2. Film-forming solution formulation:

[0261] Components Quality UV-curable acrylic resin 100 <![CDATA[Nanometer SiO2 (40nm)]]> 18 Photoinitiator (TPO) 3 Fluorine-modified acrylic leveling agent 1.2 Butyl acetate 35

[0262] 3. Coating and curing:

[0263] Spin coating (1500 rpm, 30 s), wet film thickness 8 μm.

[0264] UV curing: Mercury lamp (365nm, 600mJ / cm²) 2 ).

[0265] Performance testing

[0266] Test Project result standard Light transmittance (red / green / blue light bands) 93.2％ / 92.8％ / 92.5％ CIE203-2012 Color coordinate offset Δu'v' (650nm) <0.002 SAEJ578 Damp heat aging (85℃ / 85%RH) 1000hΔYI<1.0 IEC60068-2-78 Rain and fog simulation (spraying + strong light) No rainbow pattern / halo Self-built optical darkroom Chemical resistance (gasoline wipe) No dissolution after 100 cycles ISO2812-2

[0267] Comparison of Examples and Summary of Advantages

[0268]

[0269]

[0270] Innovative verification: Light transmittance > 91.8% + haze < 5% + UGR < 19 were achieved on five types of substrates (rigid / flexible / porous / heat resistant / optical grade), proving the universality of the technology and breaking through the boundaries of industry applications.

[0271] 1. Flexible scenario (traffic cones - dynamic bending)

[0272] 2. Extreme environments (high-altitude tunnels - freeze-thaw impact)

[0273] 3. Precision optics (signal light cover - color fidelity)

[0274] We have developed a comprehensive anti-glare solution covering all scenarios, from road infrastructure to mobile warning equipment, and strengthened the scope of patent protection and market application value.

[0275] Summary of Invention Points and Advantages

[0276] 1. Performance Breakthrough: For the first time in the field of anti-glare coatings, it simultaneously achieves top optical indicators of ≥92% light transmittance and ≤5% haze, perfectly balancing the core contradiction between "clear visibility" and "comfortable glare-free".

[0277] 2. Technological Innovation: It is the first to utilize the self-assembly of nano-quartz powder to form a surface micro-nano structure to achieve highly efficient anti-glare. The mechanism is clear and the effect is significantly better than traditional roughening or additive technologies.

[0278] 3. Process advantages: The self-assembly film forming process is relatively simple, controllable, and easy to scale up for production. It is suitable for complex shapes and large-area substrates (such as long pole-shaped light poles) and has outstanding cost-effectiveness.

[0279] 4. Superior Durability: Based on the high hardness and high stability of nano-quartz powder and the optimized resin system, the coating has excellent weather resistance, abrasion resistance, chemical resistance and mechanical strength, fully meeting the requirements for long-term use in harsh outdoor environments.

[0280] 5. Wide range of applications: The technology is highly versatile and can be widely applied to multiple key areas such as traffic safety (signs, traffic lights, light poles), building signage, and display screen protection, significantly improving public safety and visual experience.

[0281] The "quartz powder anti-glare screen coating" technology provided by this patent, with its unique design concept and excellent comprehensive performance, offers an efficient, reliable and economical solution to the glare problem in the field of outdoor signage and display, and has broad market prospects and social benefits.

[0282] Instruction manual with accompanying drawings

[0283] Figure 1Comparison of optical properties (transmittance spectrum, haze value) between the coating of this invention (solid line) and the ordinary frosted coating (dashed line).

[0284] Figure 2 Comparison of the glare effect of the coating of this invention (right) and the uncoated substrate (left) under strong light irradiation.

[0285] Figure 3 Example 1: Aging resistance performance curve of the coating (transmittance, haze vs. aging time).

Claims

1. An anti-glare coating, characterized in that, The coating comprises a transparent resin matrix and nano-quartz powder (SiO2) dispersed therein, wherein the average particle size of the nano-quartz powder is in the range of 10-100 nm; after curing, the surface of the coating forms a micro-nano protrusion structure composed of nano-quartz powder; the coating has a light transmittance ≥92% and a haze ≤5% in the visible light range.

2. The anti-glare coating according to claim 1, characterized in that, The nano-quartz powder is enriched on the coating surface through a self-assembly process and forms the micro-nano protrusion structure.

3. The anti-glare coating according to claim 1 or 2, characterized in that, The transparent resin matrix is ​​selected from acrylic resin, polyurethane resin, silicone resin, silica sol, or a combination thereof.

4. A method for preparing the anti-glare coating as described in any one of claims 1-3, characterized in that, The steps include: dispersing nano-quartz powder in a solvent containing a dispersant to form a nano-dispersion; mixing the nano-dispersion with a transparent resin and additives to form a film-forming liquid; and coating the film-forming liquid onto the surface of a substrate. By controlling the solvent evaporation process, nano-quartz powder migrates to the coating surface and self-assembles; the coating is cured to lock in the surface micro-nano structure.

5. The method according to claim 4, characterized in that, The curing methods include heat curing, ultraviolet light curing, or room temperature air drying.

6. An article comprising a substrate and an anti-glare coating as described in any one of claims 1-3 attached to at least one surface of the substrate.

7. The article of claim 6, characterized in that, The substrate is one of glass, metal, or plastic; the product is a road sign, traffic light cover, street lamp pole, utility pole, building sign, or display screen protective panel.

8. The application of the article according to claim 6 or 7 in suppressing glare while maintaining high light transmittance and visibility, particularly in the field of outdoor traffic safety or public facility signage.

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