High-light-transmittance weather-proof impact-resistant striped sound insulation board

Abstract

The invention relates to the technical field of multi-layer material preparation, in particular to a high-light-transmittance weather-proof impact-resistant striped sound insulation board. The problem that transparency, weather resistance and sound insulation effect of a traditional stripe material are difficult to consider at the same time is solved. The light scattering and absorption center is reduced and high transparency and low haze are realized through reactive extrusion of the recycled material, combination of high-temperature adsorption activated carbon, multi-stage high vacuum and deep purification of a reactive decolorizing agent, and matching of transparent dispersion diffusion master batch and a compatilizer. The surface layer adopts the core-shell weather-resistant master batch and the secondary high-energy UV fluorosilicone curing coating for double shielding of ultraviolet and inhibition of photodegradation and yellowing; styrene-maleic anhydride damping resin is introduced into the middle layer, and uniform inclined micropores and asymmetric stripes formed by supercritical CO2 are combined, so that the medium and low frequency sound insulation index is improved; the bottom layer is repaired and guaranteed to be durable in impact resistance by virtue of a core-shell toughening agent and molecular chain extension; the defects of traditional products are overcome, and the service life requirement of sound barriers for expressways and rail transit is met.

Description

Technical Field

[0001] This invention relates to the field of multilayer material preparation technology, specifically to a high-transmittance, weather-resistant, and impact-resistant striped sound insulation board. Background Technology

[0002] Transparent multi-layer barrier materials are widely used in places with high visibility requirements, such as highway curves, bridges, overpasses, and high-speed rail platforms, because they do not obstruct the driver's and passenger's view, do not create a sense of oppression, and have a good landscape coordination. At present, the mainstream transparent multi-layer barrier materials are polycarbonate (PC) striped endurance boards or PC sun boards, which have a regularly arranged longitudinal or diagonal striped structure on their surface.

[0003] Compared to opaque multilayer barrier materials such as metal and concrete, striped multilayer panels have significant advantages. They have high light transmittance, which can effectively reduce the feeling of tunnels and enclosed spaces. The striped structure can transform oncoming vehicle lights from point light sources to soft surface light sources, greatly reducing nighttime glare. They are lightweight and easy to install, and have low requirements for bridge loads, making them the preferred transparent multilayer barrier material recommended in my country.

[0004] However, existing striped multilayer panels still exhibit numerous objective problems during long-term outdoor service. Firstly, their weather resistance is insufficient. Ordinary UV coatings, under the influence of strong ultraviolet radiation, acid rain, and temperature fluctuations, show significant yellowing, a sharp increase in haze, and surface powdering and cracking after 5-8 years, resulting in a significant decrease in light transmittance and severely impacting the landscape effect and driving visibility safety. Secondly, their impact resistance is poor. Ultraviolet aging causes the PC molecular chains to break, making them prone to cracking or even penetration by hail or flying stones, posing significant safety hazards. Thirdly, sound insulation and light transmittance are difficult to balance. Increasing the panel thickness or number of cavities to improve sound insulation significantly reduces light transmittance, and the traditional striped structure has limited attenuation of low- and mid-frequency traffic noise. Fourthly, the striped grooves easily accumulate dust, bird droppings, and rainwater residue, making cleaning difficult. After long-term use, uneven light transmittance in certain areas leads to high maintenance costs. Fifthly, existing products mostly use virgin PC resin, resulting in high raw material costs and a large carbon footprint, which is incompatible with the national "dual carbon" goals and circular economy requirements. The aforementioned problems result in the actual service life of existing striped multilayer boards being only 8-12 years, far below the 30-year design life of multilayer barrier materials. Frequent replacements not only cause huge economic losses but also generate a large number of waste PC boards, creating new environmental pollution.

[0005] To address this, a high-transmittance, weather-resistant, and impact-resistant striped sound insulation board is proposed to meet the requirements for long-term stability, safety, and environmental protection of multi-layer barrier materials. Summary of the Invention

[0006] The purpose of this invention is to provide a high-transmittance, weather-resistant, and impact-resistant striped sound insulation board. It utilizes recycled material reactive extrusion, combined with high-temperature adsorption activated carbon, multi-stage high vacuum, and reactive decolorizing agents for deep purification. This, along with transparent dispersion diffusion masterbatch and compatibilizer, reduces light scattering and absorption centers, achieving high transparency and low haze. The surface layer employs a core-shell weather-resistant masterbatch and a secondary high-energy UV fluorosilicone curing coating for double UV shielding, inhibiting photodegradation and yellowing. The middle layer introduces styrene-maleic anhydride damping resin, combined with uniform oblique micropores and asymmetric stripes formed by supercritical CO2, enhancing mid-to-low frequency sound insulation. The bottom layer utilizes core-shell toughening agents and molecular chain extension repair to ensure durable impact resistance. This addresses many pain points of traditional products and meets the lifespan requirements of sound barriers for highways and rail transit.

[0007] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a high-transmittance, weather-resistant, and impact-resistant striped sound insulation board, which consists of three layers, from top to bottom: a surface layer, a middle layer, and a bottom layer; the raw materials for preparing the surface layer, middle layer, and bottom layer include polycarbonate and recycled polymethyl methacrylate. The recycled polycarbonate and polymethyl methacrylate (PMMA) base material is obtained by recycling, sorting, crushing, melting, and chain extension of polycarbonate and PMMA; In the recycling process of S1. recycled PC / PMMA base material, the temperature distribution in the twin-screw reactive extruder is 180-210-240-255-265-270-265-260-255-250-240℃, the screw speed is 450rpm, and the three-stage vacuum is -0.092MPa / -0.095MPa. The core-shell weather-resistant masterbatch was obtained by melt reaction extrusion under conditions of -0.098 MPa and residence time of 3.5 min; during the preparation of the functional masterbatch, the extrusion temperature distribution of the Φ75 twin-screw extruder was 240-260-280-290-275℃; during the melt blending process, the temperature distribution was 240-260-275-280-275℃, the screw speed was 380 rpm, and the melt blending was carried out under vacuum of -0.095 MPa. The masterbatch was then granulated underwater to obtain the core-shell weather-resistant masterbatch.

[0008] S3. During the three-layer co-extrusion molding and post-processing, the main machine temperature is 230-250-270-282-288-285-280-275℃, the auxiliary machine temperature is 225-245-265-275-280-275-270℃, the die head temperature is 280℃, the main machine screw speed is 410rpm, the auxiliary machine speed is 280rpm, and the vacuum level is -0.098MPa. The vacuum adsorption roller has a size of Φ480mm and a vacuum degree of -0.070MPa; At a traction speed of 7.1 m / min, with online edge trimming, the material is cut into standard lengths of 4 m or 6 m to obtain a fully transparent, long-lasting, weather-resistant, impact-resistant, damping striped sound insulation board based on 100% recycled PC / PMMA. The amount of activated carbon added does not affect the achievement of high light transmittance.

[0009] The raw materials for preparing the surface, intermediate, and bottom layers also include functional masterbatches; the functional masterbatches consist of transparent dispersion diffusion masterbatches and core-shell weather-resistant masterbatches. Transparent dispersion diffusion masterbatch was obtained by melt co-extrusion in a Φ75 (L / D=52) twin-screw extruder after mixing optical-grade PMMA, PMMA-coated nano-BaSO4, a fluorine surface treatment agent, and ethylene-butyl acrylate dispersant. PMMA-coated nano-BaSO4 was prepared by in-situ suspension polymerization, where 100 parts of nano-barium sulfate (particle size 50-80 nm, CAS: 7727-43-7) were dispersed in 300 parts of methyl methacrylate (MMA) monomer and ultrasonically dispersed for 30 min. 1.5 parts of azobisisobutyronitrile (AIBN) initiator and 3 parts of stearic acid modifier were added. The mixture was stirred at 75℃ under nitrogen protection for 4 hours, followed by centrifugation, ethanol washing, and vacuum drying at 80℃ to obtain core-shell structured particles with a PMMA graft layer thickness of 10-15 nm. The fluorine surface treatment agent was dodecafluoroheptyl methacrylate (CAS: 2261-99-6).

[0010] After melting the surface layer, intermediate layer, and bottom layer raw materials separately, supercritical carbon dioxide is injected during the melting and extrusion process of the intermediate layer raw material. It is then combined with the surface and bottom layer melts via a distributor, rolled to form a striped structure, and then shaped and cooled in three stages. After being completely immersed in a fluorosilane solution for 3 minutes, it is UV cured and finished to obtain a high-transmittance, weather-resistant, and impact-resistant striped sound insulation board. The fluorosilane solution consists of 5% by mass of 1H,1H,2H,2H-perfluorooctyltriethoxysilane hydrolysate and 95% solvent. The solvent consists of 65% trimethylolpropane triacrylate, 25% 1,6-hexanediol diacrylate, 8% photoinitiator Irgacure 184, and 2% leveling agent polyether-modified silicone oil (Dow Corning DC-67). The preparation method of the 1H,1H,2H,2H-perfluorooctyltriethoxysilane hydrolysate is as follows: 1H,1H,2H,2H-perfluorooctyltriethoxysilane (CAS: 51851-37-7), anhydrous ethanol, deionized water and glacial acetic acid were mixed in a mass ratio of 100:50:15:1 and magnetically stirred at 25°C for 4 hours to carry out a pre-hydrolysis reaction to obtain the product.

[0011] A small amount of ethanol introduced during pre-hydrolysis acts as a co-solvent, enabling the polar silanol oligomers to be miscible with the acrylate monomers. Under the thermal effects of impregnation and subsequent UV curing, the active silanol groups undergo a condensation reaction with the functional groups on the PC / PMMA substrate surface to form anchoring points; simultaneously, the perfluorinated long chains migrate to the coating surface to achieve hydrophobicity, while the acrylate monomers rapidly crosslink to form an interpenetrating network, thereby achieving dual adhesion of chemical bonding and physical locking.

[0012] Through a three-stage cooling process, the sheet material exits the machine at 230°C. Direct rapid cooling would generate significant internal stress due to the temperature difference between the surface and core exceeding 80°C, leading to stripe collapse or bulging. The three-stage progressive cooling allows the surface layer to solidify slowly first (85°C, still above PCTg), maintaining the stripe shape, and then gradually cooling to below 50°C for complete shaping. Stripe height tolerance can be controlled within ±0.05mm. If cooled directly to below 50°C, the PC molecular chains do not have enough time to relax, resulting in microcracks at the stripe roots, causing whitening and haze after light refraction. The three-stage process allows sufficient time for the molecular chains to arrange themselves in an orderly manner, reducing haze. The middle layer features supercritical CO2 micro-foaming. If the surface layer is too cold while the core temperature is still above 180°C, the internal and external pressure difference would crush the micropores. The three-stage process ensures slow cooling of the core, allowing the micropores to solidify before complete cooling, improving pore size uniformity and Rw stability.

[0013] Preferably, the core-shell weather-resistant masterbatch is obtained by melt blending polymethyl methacrylate, benzotriazole UV absorber (UV-326) and maleic anhydride-grafted polymethyl methacrylate; then, the surface of the core-shell weather-resistant masterbatch is coated with dodecafluoroheptyl methacrylate and vinyltrimethoxysilane, and after adding an initiator, it is reacted and extruded.

[0014] Preferably, the raw materials for preparing the intermediate layer also include styrene-maleic anhydride damping resin and hollow glass microspheres. The styrene-maleic anhydride damping resin has a glass transition temperature of 138℃, forming an extremely wide damping plateau with PC (Tg 148℃) and PMMA (Tg 105℃) (tanδ > 0.5 from -20℃ to +100℃), achieving a high loss factor (tanδ 0.7-0.8) at room temperature. Vibration energy is efficiently converted into heat dissipation, significantly improving sound insulation. The hollow glass microspheres have a CAS number of 65997-17-3 and a true density of 0.46 g / cm³. 3 It has a refractive index of 1.51 and is well-matched when blended with PC1.586 and PMMA1.491; its thermal conductivity is 0.10-0.12 W / m·K.

[0015] Preferably, the underlying raw materials also include surface-activated short-cut carbon fibers.

[0016] Preferably, the surface-activated chopped carbon fiber is obtained by activating chopped carbon fiber after soaking in nitric acid.

[0017] The preparation method of SMA compatibilizer is as follows: Step 1 - Preparation of monomer solution: In a 500mL four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen inlet, add 400 parts of dry toluene, 70.4 parts of styrene monomer and 29.6 parts of maleic anhydride monomer, start stirring, protect the system with nitrogen, heat to 60℃, stir for 30min, and ensure that MAH is completely dissolved.

[0018] Step 2 - Random copolymerization reaction: At 60°C, 0.3 parts of benzoyl peroxide (BPO) initiator were added to the reaction system in three portions at 15-minute intervals, with each addition being an even distribution. The reaction temperature was slowly increased to 85°C and maintained at this temperature for 6 hours. During the reaction, a slight positive pressure of nitrogen was maintained, and the stirring speed was 300 rpm to ensure uniform reaction. After 6 hours of reaction, 0.1 parts of antioxidant octadecyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate (Irganox1076) stabilizer were added, and the reaction system was cooled to 50°C.

[0019] Step 3 - Separation, Purification and Drying: The reaction solution was slowly added dropwise to 10 times its volume of anhydrous methanol under stirring to precipitate. The precipitate (i.e., SMA copolymer) was collected by filtration through a Buchner funnel. The collected precipitate was placed in a vacuum oven at 80°C and dried for 24 hours until the mass was constant. The dried polymer was crushed and passed through an 80-mesh sieve to obtain SMA compatibilizer powder; the grafting rate was 8%.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. By introducing high-temperature adsorption activated carbon through the reactive extrusion stage of recycled materials and combining it with multi-stage high-vacuum deep purification technology, ink, degraded color base and colored small molecules are removed. At the same time, with the synergistic effect of transparent dispersion diffusion masterbatch and highly active compatibilizer, the light scattering and absorption centers inside the melt are reduced, so that the board has high transparency and low haze. This solves the problem of graying and yellowing that occurs when recycled materials are used to make transparent sound barrier boards, and maintains the landscape transparency and driving visibility requirements under service conditions.

[0021] 2. A dual shielding system is adopted, consisting of a surface core-shell weather-resistant masterbatch and a secondary high-energy UV fluorosilicone curing coating. The weather-resistant masterbatch is enriched on the surface to form a UV absorption layer. Combined with the high cross-linking density of the coating, it blocks the penetration of ultraviolet rays into the interior of the substrate, inhibits photofrigh's rearrangement and molecular chain oxidative degradation, and improves the weather resistance of the board, so that it does not yellow or powder under UV and acid rain environments.

[0022] 3. Through the compatibility design of the core-shell toughening agent and the PC / PMMA blend system, combined with the chain extension and repair technology of recycled material molecular chains, the chain entanglement density is maintained. At the same time, the surface weather-resistant system prevents the inward diffusion of ultraviolet aging, improves the impact strength retention rate after aging, and enables the board to resist hail and flying stone impacts during outdoor service, thus extending the service life of the sound barrier.

[0023] 4. High Tg styrene-maleic anhydride damping resin is introduced into the intermediate layer and compatibility with the base material is achieved to form a high loss factor constrained damping structure. At the same time, the uniform oblique micropores controlled by supercritical CO2 and the asymmetric stripes work together to establish a sound wave multiple reflection-viscous energy dissipation path, which improves the attenuation ability of low and medium frequency traffic noise and enhances the sound insulation of the single panel.

[0024] 5. By integrating the weather-resistant layer, damping micro-foamed functional layer, and impact-resistant reinforcement layer through a three-layer co-extrusion process, combined with the asymmetric stripes formed by online vacuum adsorption rollers and shaping molds, and the self-cleaning performance provided by the secondary UV fluorosilicone coating, a synergistic effect of high light transmittance, weather resistance, impact resistance, sound insulation and easy cleaning is achieved. This solves the problem of insufficient single performance of traditional striped sound insulation panels and meets the design life requirements of sound barriers for highways and rail transit. Attached Figure Description

[0025] Figure 1 This is a process flow diagram for the preparation of the high-transmittance, weather-resistant, and impact-resistant striped sound insulation board of the present invention. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Please see Figure 1 This invention provides a high-transmittance, weather-resistant, and impact-resistant striped sound insulation board, the technical solution of which is as follows: Example 1 S1. Deep purification and molecular chain repair of recovered PC / PMMA base materials. The initial weight-average molecular weight (Mw) of the recovered materials is in the range of 45,000 to 65,000 g / mol, and the initial yellow index (YI) value is less than 15. The recovered materials are first sorted and crushed into 6 to 8 mm particles, and then vacuum dried at 150℃ and -0.095 MPa for 6 hours. Subsequently, 100 parts of recovered PC particles, 100 parts of recovered PMMA particles, 1.5 parts of reactive decolorizing agent (bisphenol A, bis(diphenyl phosphate) BDP and phosphite in a 1:1 mass ratio), and high-temperature adsorption activated carbon powder (specific surface area greater than 1800 m²) are added.2 The mixture was formulated with 4.0 parts of epoxy chain extender (average particle size D50 of 150 μm), 0.6 parts of SMA compatibilizer, 4.5 parts of ethyltriphenylphosphine bromide, 0.05 parts of ethyltriphenylphosphine bromide, and 0.8 parts of antioxidant compound. The mixture was melt-reacted in a Φ58 twin-screw extruder (L / D ratio L / D = 56), with the temperature controlled between 180 and 270 °C, a screw speed of 450 rpm, a triple vacuum of -0.098 MPa, and a residence time of 3.5 min. After underwater hot-face pelletizing, ultra-clean R-PC / PMMA recycled base material was obtained, with a PC to PMMA mass ratio of 1:1. S2. Preparation of Functional Masterbatch The functional masterbatch comprises a three-layer transparent dispersion diffusion masterbatch and a core-shell weather-resistant masterbatch. The transparent dispersion diffusion masterbatch is obtained by melt co-extrusion at 270-290℃ in a Φ75 (L / D=52) twin-screw extruder after mixing 60 parts optical-grade PMMA, 35 parts PMMA-coated nano-BaSO4, 3 parts fluorine surface treatment agent, and 2 parts ethylene-butyl acrylate dispersant. The core-shell weather-resistant masterbatch is first prepared by melt blending 60 parts optical-grade PMMA, 30 parts benzotriazole UV absorber, 5 parts hindered amine HALS, 0.8 parts antioxidant, and 4.2 parts MAH-grafted PMMA in a Φ65 (L / D=48) twin-screw extruder at 240-280℃. Subsequently, 100 parts of core-shell weather-resistant masterbatch were used as the main material, and 12 parts of dodecafluoroheptyl methacrylate (DFMA), 5 parts of vinyltrimethoxysilane (A-171), 0.3 parts of initiator benzoyl tert-butyl peroxide, and 0.2 parts of zinc stearate were added to the side feed zone. The mixture was reacted and extruded in a Φ75 twin-screw extruder at a speed of 380 rpm and a vacuum of -0.095 MPa, ultimately yielding core-shell masterbatch with an average particle size of 150 nm and a fluorine content of 5.2%.

[0028] S3. Three-layer co-extrusion molding and post-processing: First, the 1:1 base material prepared in S1 was adjusted by adding pure PC to form the required PC / PMMA ratio for the three layers: surface layer 52:48, middle layer 65:35, and bottom layer 70:30. The surface layer also contained 15 parts core-shell weather-resistant masterbatch, 8 parts transparent dispersion diffusion masterbatch, 1.8 parts nano-TiO2 (R-960 coated type), 0.8 parts HALSTinuvin 622, and SMA compatibility. The intermediate layer also includes 18 parts of styrene-maleic anhydride damping resin Dylark 332, 12 parts of core-shell weather-resistant masterbatch, 10 parts of transparent dispersion diffusion masterbatch, 5.5 parts of hollow glass microspheres 3MK46, and 4.5 parts of SMA compatibilizer; the bottom layer also includes 20 parts of core-shell weather-resistant masterbatch, 4.5 parts of surface-activated short-cut carbon fiber, 6 parts of transparent dispersion diffusion masterbatch, and 3.5 parts of SMA compatibilizer; the total amount of PC and PMMA in each layer is 100 parts.

[0029] All formulations were dried at 120℃ for 8 hours using forced air drying. The surface-activated chopped carbon fibers used in the bottom layer were obtained by activating carbon fibers (average particle size 7-10μm) by soaking them in 15% nitric acid for 30 minutes and then drying them. The three layers were fed to the Φ120 main extruder and the Φ75 auxiliary extruder for melt co-extrusion, with the main and auxiliary machine temperatures controlled at 230-288℃ and 225-280℃ respectively, and the die head temperature at 280℃. During extrusion, a four-level vacuum (-0.098MPa) was maintained, and supercritical CO2 was injected into the middle layer through zone 9 at a continuous injection rate of 20g / min. The melt formed a three-layer structure through a three-layer distributor. The melt first entered a vacuum adsorption roller at 95℃, where it was rolled to form a striped structure, and then entered a precision shaping die for final shaping and cooling. Cooling was performed in three stages: the first stage was at 85℃ for 15 seconds, the middle stage at 65℃ for 20 seconds, and the last stage at 50℃ for 25 seconds. After exiting the molding die, the sheet material immediately enters an impregnation tank containing UV monomers and fluorosilane solution, and undergoes double-sided impregnation at 14500 mJ / cm². 2 UV light irradiation for 25 seconds cures the material, forming a long-lasting, self-cleaning, weather-resistant film. Finally, through traction, edge trimming, and cutting, a fully transparent, long-lasting, weather-resistant, impact-resistant, damping striped sound insulation board is obtained; its final thickness is 0.7mm for the surface layer, 9.6mm for the middle layer, and 0.7mm for the bottom layer.

[0030] Examples 2-5 Unlike Example 1, the following preparation conditions were changed, as shown in Table 1.

[0031]

[0032] Comparative Examples 1-6 Except for some parameter adjustments, the preparation methods described below are consistent with those in Example 1.

[0033] Comparative Example 1 No high-temperature activated carbon was added, and 3.5 parts of PC and PMMA were mixed in equal proportions as a supplementary material.

[0034] Comparative Example 2 No surface core-shell weather-resistant masterbatch was added, and 13 parts of PC and PMMA were mixed in equal proportions as a supplementary material.

[0035] Comparative Example 3 The highest temperature in the reactive extrusion zone of the recycled material is 310℃.

[0036] Comparative Example 4 The melt blending temperature is 240-250℃.

[0037] Comparative Example 5 Foaming is carried out solely through chemical foaming, i.e., by adding 0.5% azodicarbonamide AC as the intermediate layer for chemical foaming, without introducing supercritical CO2.

[0038] Comparative Example 6 The UV-cured fluorosilicone energy density is 13000 mJ / cm².

[0039] Test Example 1 The light transmittance of the striped sound insulation boards prepared in the examples and comparative examples was tested. Referring to GB / T2410-2008 "Determination of Light Transmittance and Haze of Transparent Plastics", a WGT-S transmittance / haze meter (Shanghai Precision Instruments Co., Ltd.) was used for testing with a D65 standard light source and a uniform sample thickness of 10 mm. The instrument was preheated for 30 minutes and zeroed and calibrated using a standard black tube and white board. A clean, scratch-free 10 mm thick board sample was vertically placed into the sample chamber. The transmittance (τ) and haze values ​​were read separately, repeated three times, and the average was taken. The test was conducted at 23℃ and 50% relative humidity. The test results are summarized in Table 2.

[0040]

[0041] The test results above show that the light transmittance of Examples 1-5 is ≥89.2%, and the haze is ≤3.1%, which fully meets the mandatory requirements of JT / T646-2016 "Technical Requirements for Highway Sound Barrier Materials" for transparent sound barrier panels, which stipulates a light transmittance of ≥85% and a haze of ≤5%. Through activated carbon and three-stage high-vacuum deep decolorization, colored degradation products in the recycled material are removed. Transparent dispersion diffusion masterbatch and highly active SMA compatibilizer reduce the refractive index difference between PC and PMMA, eliminating phase separation scattering. Supercritical CO2 controls the micropore size, making it much smaller than the visible light wavelength to avoid Mie scattering. A secondary UV fluorosilicone coating forms a smooth surface, further reducing surface scattering, thus ensuring that the material ultimately has good light transmittance.

[0042] In Comparative Example 1, residual ink, pyrolysis products of the aluminum plating layer, styrene yellowing groups, phenolic oxides, and other colored small molecules in the recycled material were not completely removed. These formed numerous absorption and scattering centers in the melt, resulting in severe graying and yellowing, and reduced light transmittance. In Comparative Example 3, excessively high temperatures triggered secondary thermo-oxidative degradation of PC / PMMA, producing new quinone and stilbene chromophores. Simultaneously, molecular chain breakage released small volatile molecules, forming microbubbles and carbonization points within the board. This dual absorption and scattering caused reduced light transmittance. In Comparative Example 4, excessively low temperatures prevented the damping resin from fully melting and diffusing with the base material and MBS core-shell particles, forming phase-separated micro-regions of tens of micrometers. This resulted in stratification between the PC-rich and PMMA-rich regions, and the difference in refractive index directly caused strong scattering, significantly increasing haze. In Comparative Example 5, uneven decomposition of the chemical foaming agent led to macropores and co-pores. The pore size approached the visible light wavelength, triggering strong Mie scattering; simultaneously, the rough pore walls further increased diffuse reflection. In Comparative Example 6, insufficient curing energy resulted in low cross-linking degree of the fluorosilicone coating, with minor surface irregularities remaining, slightly increasing surface scattering; however, it had little impact on light transmittance during the new board stage.

[0043] Test Example 2 The striped sound insulation panels prepared in the examples and comparative examples were subjected to weathering tests, specifically in accordance with GB / T16422.2-2022 "Laboratory Light Source Exposure Test Methods for Plastics - Part 2: Xenon Arc Lamp". A Ci5000 xenon lamp aging test chamber (Atlas) was used, equipped with a 5000W water-cooled xenon arc lamp. The black standard temperature was 65℃, the chamber temperature was 40℃, the relative humidity was 50%, the irradiance was 0.55W / m²@340nm, and the continuous exposure was 8000h - equivalent to about 12 years of natural outdoor exposure in southern regions. Each cycle was 24h, with 102min of light exposure and 18min of light exposure while spraying water.

[0044] The yellowing index was determined using a Colori7 spectrophotometer (X-Rite) before and after aging, with a D65 light source, 10° field of view, and SCI mode, according to GB / T3979-2008, measuring Δb* (color difference along the blue-yellow axis, a positive value indicates yellowing). Five points were measured for each sample group, and the average value was taken. The test results are shown in Table 3.

[0045]

[0046] The test results above show that after 8000 hours of xenon lamp aging, the yellowing index Δb of Examples 1-5 is only 0.7-1.8, which fully meets the 20-year weather resistance requirement of the sound barrier industry (Δb≤3.0). The high-load core-shell weather-resistant masterbatch on the surface of the material in the examples is enriched on the surface in the melt to form an effective barrier layer. Combined with the secondary UV fluorosilicone highly cross-linked coating, it doubles the blocking of ultraviolet rays from penetrating into the substrate. At the same time, the recycled material is thoroughly treated with activated carbon and high vacuum to remove phenolic and quinone precursor colorants, eliminating the source of yellowing from the source.

[0047] Comparative Example 1: The lack of activated carbon resulted in a large amount of residual phenolic oxides and degradation molecules in the recycled material, which were rapidly oxidized into quinone chromophores under ultraviolet light, accelerating yellowing. Comparative Example 2: Completely lacking a surface-layered core-shell weather-resistant masterbatch, ultraviolet light directly penetrated the surface of the board, triggering PC photo-Fries rearrangement and producing a large number of chromophore structures, resulting in the most severe yellowing. Comparative Example 3: Excessive high temperature during the reaction stage of the recycled material produced a large number of newly formed quinone and stilbene structures. These structures themselves are strong chromophores, which were activated in the early stages of aging, exacerbating yellowing. Comparative Example 4: The excessively low temperature of the main unit had little impact on weather resistance, mainly because the weather-resistant layer still functioned independently on the surface. Comparative Example 5: Little impact on weather resistance. Comparative Example 6: Severely insufficient UV curing energy, low cross-linking degree of the fluorosilicone coating, high ultraviolet transmittance, rapid powdering and peeling of the weather-resistant layer, loss of shielding function, and a sharp increase in yellowing.

[0048] Test Example 3 The striped sound insulation boards prepared in the examples and comparative examples were subjected to impact resistance tests. Referring to GB / T1843-2008 "Determination of Impact Strength of Notched Cantilever Beams in Plastics", the tests were conducted using a ZBC1400-2 pendulum impact testing machine at 23℃ and 50% relative humidity. Lateral impact was performed with a pendulum energy of 5.5J. The sample size was 80mm × 10mm × 10mm, with a type A notch (depth 2mm, tip radius 0.25mm), a span of 60mm, and 10 samples per group. The average value was taken. The impact performance was tested after 8000h accelerated aging under a xenon lamp (GB / T16422.2-2022 Method A), and the weather resistance was evaluated by the strength retention rate; the test results are shown in Table 4.

[0049]

[0050] The test results above show that the impact strength retention rate after aging in Examples 1-5 reached 90.5%-96.8%, far exceeding the industry standard of 70%-80%. The core-shell ACR / MBS toughening agent provides durable toughening; the PC / PMMA blend system forms wide-temperature-range damping to absorb impact energy; and the surface weather-resistant masterbatch and high-energy UV fluorosilicone coating effectively block ultraviolet light penetration, preventing photodegradation and breakage of molecular chains. Simultaneously, the recycled material, after chain extension and repair, restores its molecular weight to its original level, resulting in high chain entanglement density, ultimately leading to excellent weather resistance of the striped sound insulation board.

[0051] Comparative Examples 1 and 5 show that colored impurities and supercritical CO2 have relatively little impact on the final impact strength and weather resistance. Comparative Example 2, with its core-shell weather-resistant masterbatch without a surface layer, experienced direct UV irradiation of the substrate, inducing photofries rearrangement and chain breakage, resulting in aging embrittlement and a significant decrease in impact retention. Comparative Example 3, with its recycled material reacting at excessively high temperatures, led to a secondary decrease in molecular weight and reduced chain entanglement, resulting in a sharp increase in brittleness after aging and the lowest retention rate. Comparative Example 4, with its excessively low melt extrusion temperature, resulted in poor compatibility between the core-shell toughening agent and the base material, uneven particle dispersion, localized agglomeration, and the formation of stress concentration points, significantly reducing impact strength after aging. Comparative Example 6, with insufficient UV curing, resulted in inadequate cross-linking of the fluorosilicone coating, significantly increased UV transmittance, and rapid surface photodegradation, leading to a significant deterioration in overall impact resistance in the later stages of aging.

[0052] Test Example 4 The sound insulation performance of the striped sound insulation panels used in the examples and comparative examples was tested. Specifically, the methods were followed according to GB / T19889.3-2005 "Acoustic Measurement of Sound Insulation of Buildings and Building Components - Part 3: Laboratory Measurement of Airborne Sound Insulation of Building Components"; The system used was a B&K4206 dual reverberation chamber system, a B&K2270 sound level meter, and a Norsonic Nor276 power 1 / 3 octave band analyzer. The sample installation area was 10 m² (3.3 m × 3.0 m); the volume of the sound-generating chamber was 220 m³, and the volume of the receiving chamber was 180 m³; the background noise was ≤15 dB(A), the temperature was 23 ± 2℃, and the relative humidity was 50 ± 5%; the frequency range was 100 Hz-5000 Hz (1 / 3 octave band); the sound source was pink noise.

[0053] The single-value weighted sound insulation Rw (including C and Ctr spectral correction coefficients) was calculated according to Appendix A of GB / T50121-2005 "Standard for Evaluation of Building Sound Insulation"; the sound insulation was measured once on the front and back of each sample and the average value was taken. According to GB / T18258-2000 "Determination of Loss Factor and Storage Modulus of Damping Materials by Dynamic Mechanical Analysis (DMA)", a TA Instruments Q800 dynamic mechanical analyzer was used. The sample size was 35mm×12mm×4mm (cut from the plate). The test mode was single cantilever beam mode, the frequency was 1Hz, corresponding to the main frequency band of traffic noise; the temperature scan range was -50℃ to 150℃, and the heating rate was 3℃ / min; the tanδ peak value under normal service conditions at 25℃ was taken as the evaluation index; 5 samples were taken in each group, and the average value was taken. The final test results are shown in Table 5.

[0054]

[0055] The test results above show that the weighted sound insulation Rw of Examples 1-5 reaches 31.4-33.8dB, which is 6-9dB higher than that of traditional solid PC boards, exceeding the requirement of ≥30dB in JT / T646-2016. The damping loss factor tanδ reaches 0.62-0.78, which is highly positively correlated with Rw. The high Tg styrene-maleic anhydride damping resin in the middle layer of the striped sound insulation board of Examples forms a wide temperature range high loss factor with PC / PMMA, realizing constrained damping vibration reduction. The uniform oblique closed-pore microporous structure is formed by supercritical CO2 and chemical foaming. The sound waves are reflected multiple times and dissipated by viscosity in the pores. The stripes and internal micropores work together to form a multi-level sound wave diffraction-dissipation path, which is most significant for attenuating traffic noise in the 200-1000Hz range.

[0056] In Comparative Example 1, the absence of activated carbon had almost no impact on sound insulation because colored impurities do not change the material density and damping characteristics. Comparative Example 2, lacking a surface weather-resistant masterbatch, had no impact on sound insulation, and its contribution was negligible. Comparative Example 4, with its excessively low melting temperature, resulted in severe phase separation between the damping resin and the base material, reducing the damping loss factor and causing the constraint damping structure to fail. Comparative Example 5, lacking supercritical CO2 and relying solely on chemical foaming, exhibited the most significant issues: uneven micropore size and severe co-occurrence, disrupting the sound wave viscous energy dissipation path. The damping loss factor tanδ showed a highly linear positive correlation with the weighted sound insulation Rw. Comparative Examples 4 and 5 represent two typical mechanisms: "damping resin compatibility failure" and "micropore uniformity failure," respectively, directly leading to a significant decrease in both tanδ and Rw. This fully demonstrates that precise control of the main unit temperature and supercritical CO2 is a core and indispensable process for achieving high sound insulation. The synergistic effect of the above preparation and process schemes results in the striped sound insulation board of this invention possessing excellent light transmittance, weather resistance, good mechanical strength, and sound insulation performance.

[0057] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0058] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A high-transmittance, weather-resistant, and impact-resistant striped sound insulation board, characterized in that: The high-transmittance, weather-resistant, and impact-resistant striped sound insulation board consists of three layers, from top to bottom: a surface layer, a middle layer, and a bottom layer; the raw materials for preparing the surface layer, the middle layer, and the bottom layer include recycled polycarbonate and polymethyl methacrylate. The recycled polycarbonate and polymethyl methacrylate base material is obtained by recycling, sorting, crushing, melting and chain extension of polycarbonate and polymethyl methacrylate; The raw materials for preparing the surface layer, the intermediate layer, and the bottom layer also include functional masterbatch; the functional masterbatch is composed of transparent dispersion diffusion masterbatch and core-shell weather-resistant masterbatch; After melting the surface material, intermediate layer material and bottom layer material separately, supercritical carbon dioxide is injected during the melting and extrusion process of the intermediate layer material. Then, it is combined with the surface and bottom layer melts through a distributor, rolled to form a striped structure, and then shaped and cooled in three stages. After impregnation, it is cured with ultraviolet light and finished to obtain a high light transmittance, weather-resistant and impact-resistant striped sound insulation board.

2. A high-transmittance, weather-resistant, and impact-resistant striped sound insulation board according to claim 1, characterized in that: The core-shell weather-resistant masterbatch is obtained by melt blending polymethyl methacrylate, benzotriazole UV absorber and maleic anhydride-grafted polymethyl methacrylate; then, the core-shell weather-resistant masterbatch is coated with dodecafluoroheptyl methacrylate and vinyltrimethoxysilane, and then reacted and extruded after adding an initiator.

3. A high-transmittance, weather-resistant, and impact-resistant striped sound insulation board according to claim 1, characterized in that: The raw materials for preparing the surface layer also include nano-titanium dioxide, polysuccinic acid-(4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol) ester, and a compatibilizer.

4. A high-transmittance, weather-resistant, and impact-resistant striped sound insulation board according to claim 3, characterized in that: The compatibilizer is obtained by solution polymerization.

5. A high-transmittance, weather-resistant, and impact-resistant striped sound insulation board according to claim 4, characterized in that: The solution polymerization reaction involves dissolving styrene monomer and maleic anhydride monomer to form a monomer solution. Random copolymerization was carried out after adding the initiator to the monomer solution in portions. The obtained product was added to anhydrous methanol to precipitate, filtered, dried, and pulverized.

6. A high-transmittance, weather-resistant, and impact-resistant striped sound insulation board according to claim 1, characterized in that: The raw materials for preparing the intermediate layer also include styrene-maleic anhydride damping resin and hollow glass microspheres.

7. A high-transmittance, weather-resistant, and impact-resistant striped sound insulation board according to claim 1, characterized in that: The raw materials for preparing the bottom layer also include surface-activated short-cut carbon fibers.

8. A high-transmittance, weather-resistant, and impact-resistant striped sound insulation board according to claim 7, characterized in that: The surface-activated chopped carbon fiber is obtained by activating chopped carbon fiber by soaking it in nitric acid; the light transmittance of the high-transmittance, weather-resistant, and impact-resistant striped sound insulation board is 89.2%-91.5%.

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