Impact-resistant high-transparency acrylic sheet, and extrusion and calendering equipment and process thereof

Abstract

This invention relates to the field of polymer material processing technology, specifically to an impact-resistant, high-transparency acrylic sheet and its extrusion and calendering equipment and process, comprising the following components in parts by weight: 80-85 parts methyl methacrylate; 0.07-0.09 parts azobisisobutyronitrile; 0.001 parts hydroquinone; and 15-20 parts toughening masterbatch. The particle size of the toughening masterbatch is 2.0 mm to 2.5 mm, and the particle size difference between the polymethyl methacrylate particles and the toughening masterbatch is 0.2 mm to 0.5 mm. By combining a specific composite toughening masterbatch formula with precisely controlled particle size distribution, it can effectively resist the impact of door closing and object bumps, ensuring the structural integrity and durability of the components. The haze is ≤0.45%, which meets the stringent requirements for the "high-end" and transparent appearance of decorative parts such as A-pillars and trim strips, avoiding visual blurring caused by toughening.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer material processing, in particular to a high-performance polymethyl methacrylate (PMMA, commonly known as acrylic) plate and its manufacturing technology, and more particularly to an acrylic plate with excellent impact resistance and high light transmittance, and an integrated extrusion and calendering production equipment and process. BACKGROUND

[0002] Acrylic plate, i.e. polymethyl methacrylate plate, has a wide application potential in the field of automotive interior and exterior decoration (such as A-pillar cover plate, center console decorative strip, lamp decoration ring, intelligent surface cover plate, etc.) due to its high light transmittance, easy shaping, strong coloring ability and excellent surface gloss. Compared with traditional engineering plastics or glass, PMMA has more excellent visual transparency and design freedom, which is beneficial to improve the aesthetic quality and human-computer interaction experience of the interior. However, when it is applied to the field of automobile which has extremely strict requirements on material performance, the existing conventional acrylic plate or modification technology exposes the following bottlenecks, resulting in limited application range and questionable reliability: First, the comprehensive performance is difficult to balance. The existing technology for improving the toughness of the acrylic plate (such as adding rubber elastomer, MBS resin, etc.) can improve the impact strength to some extent, but often at the cost of sacrificing light transmittance and surface gloss, resulting in a significant increase in haze. For automotive applications that emphasize visual clarity and interior "high-grade", even slight fogging can seriously affect the appearance and functionality (such as optical display effect). At the same time, the conventional toughening scheme may cause the surface to be not wear-resistant and easy to scratch, affecting the service life due to the loss of hardness of the plate.

[0003] ‌Second, the weather resistance and aging performance are insufficient. Automotive components are subjected to high-intensity ultraviolet radiation, extreme temperature cycles (extreme heat and extreme cold), high humidity environments, and atmospheric pollutant erosion for a long time. Ordinary PMMA plate has poor impact resistance, and if ordinary toughening agents are added, the toughening components and the matrix may separate, migrate or degrade under thermal oxidative aging and light aging, causing the plate to become brittle, yellow or crack, not only deteriorating the appearance, but also possibly causing stress cracking and a sharp decrease in strength. Although light stabilizers and antioxidants are added in traditional technology, they often cannot effectively cooperate in the toughening system, and long-term durability cannot be guaranteed.

[0004] Third, unstable production processes affect product quality consistency. Conventional extrusion or casting processes typically involve mechanically mixing pre-prepared toughening masterbatch with PMMA particles and then melting it to form a final product. This method makes it difficult to guarantee absolutely uniform dispersion of the toughening agent in the PMMA matrix on a macroscopic scale, easily leading to particle size segregation, local agglomeration, and other phenomena. This results in uneven impact strength distribution and defects in the final product. Furthermore, because the raw material particle size is not precisely matched in conventional methods, particles of different densities and flowability are prone to stratification or "melt memory" during mixing, conveying, and melting. This causes significant fluctuations in key optical and mechanical properties (such as transmittance, haze, and impact strength) of automotive sheet metal between batches or within the same batch, failing to meet the stringent requirements of the automotive industry for component stability. Therefore, the disconnect between existing acrylic sheets in terms of toughness, light transmittance, weather resistance, and manufacturing process stability has become a key obstacle restricting their large-scale application in high-end automotive parts, especially in visual and intelligent surface components that simultaneously require "impact resistance, high light transmittance, high weather resistance, and stable performance." The industry urgently needs a systematic solution that not only resolves the contradiction between traditional toughening and light transmittance but also ensures the material's performance stability after long-term aging and enables high-quality industrial mass production.

[0005] Therefore, how to significantly improve the impact resistance of PMMA sheets without sacrificing their high light transmittance, and ensure their long-term stability under automotive-grade weather resistance requirements, has become a pressing technical challenge in this field. Summary of the Invention

[0006] To address the aforementioned technical challenges, this invention aims to provide an acrylic sheet with high impact resistance and excellent light transmittance, along with its preparation equipment and process. It fundamentally solves problems such as uneven mixing and agglomeration of toughening agents and the matrix, and enables continuous, efficient, and high-quality stable production.

[0007] To achieve the above-mentioned objectives, the present invention adopts the following systematic technical solution: In a first aspect, the present invention provides an impact-resistant, high-transmittance acrylic sheet.

[0008] The acrylic sheet is made of the following components in parts by weight: 80-85 parts methyl methacrylate, 0.07-0.09 parts azobisisobutyronitrile (AIBN) (as a polymerization initiator), 0.001 parts hydroquinone (BHT) (as a polymerization inhibitor), and 15-20 parts toughening masterbatch.

[0009] The toughening masterbatch includes components such as polymethyl methacrylate, acrylate, aliphatic polyether, pentaerythritol ester, phosphite, benzophenone-based UV absorbers, and lubricants, forming a composite toughening modification system.

[0010] To achieve uniform dispersion of the toughening agent in the matrix and prevent agglomeration, this invention creatively controls the particle size of the polymethyl methacrylate (PMMA) particles constituting the acrylic sheet to be between 2.5 mm and 3.0 mm, while the particle size of the toughening masterbatch is controlled to be between 2.0 mm and 2.5 mm. Furthermore, the particle size difference between the PMMA particles and the toughening masterbatch is precisely limited to the range of 0.2 mm to 0.5 mm. By controlling this specific particle size range and particle size difference, the two materials possess similar flowability and thermal melting behavior during subsequent melt blending, minimizing flow stratification and toughening agent agglomeration caused by differences in particle size and density. This is one of the key factors in ensuring that the sheet achieves high light transmittance and uniform high toughness.

[0011] Preferably, the toughening masterbatch has the following specific weight composition: 75 parts methyl methacrylate, 20 parts acrylate, 3 parts aliphatic polyether, 0.6 parts pentaerythritol ester, 0.8 parts phosphite, 0.4 parts benzophenone-based UV absorber, and 0.2 parts lubricant. This formulation ensures polarity matching between the toughening agent components and the PMMA matrix, excellent compatibility, and synergistic function of each component.

[0012] Furthermore, the toughening masterbatch also includes a polyether ester-based transparent antistatic agent. This antistatic agent can be prepared in situ and then added to form a stable conductive network, giving the board a long-lasting antistatic capability without affecting light transmittance.

[0013] Secondly, the present invention provides a dedicated extrusion calendering apparatus for preparing the above-mentioned impact-resistant, high-transparency acrylic sheet.

[0014] This device is a highly integrated, all-in-one system, characterized by including: Main body of the production unit: Constituting the main frame of the equipment.

[0015] The pre-preparation component's core function is to achieve "online preparation and screening" of toughening masterbatch. This component includes a screw conveyor granulation unit, a cooling unit, and a separation and conveying unit, all connected in sequence. Specifically, the screw conveyor granulation unit includes a screw conveyor with an inlet C, at the end of which a granulation screen is fixed; the cooling unit is a closed cooling circulation pipeline; and the separation and conveying unit includes a separation box and a built-in auger and separation screen. The pre-preparation component can directly process the raw material of toughening masterbatch into specific particles with a diameter of 2.0 mm to 2.5 mm online.

[0016] Dual feeding assembly: Located on the main body of the production unit, it includes two independent feeding hoppers A arranged side by side. One feeding hopper A is used to receive pre-prepared PMMA granules with a particle size of 2.5-3.0mm, while the other feeding hopper A is connected to the conveying end of the pre-preparation assembly via pipeline, specifically for receiving toughening masterbatch particles of a specific particle size after online preparation and screening. Each feeding hopper is equipped with an independent, servo motor-driven stirring and conveying mechanism, enabling precise metering and synchronous feeding of both materials.

[0017] Extrusion assembly: Includes a fixed shell and its internal screw conveyor. The fixed shell is connected to the bottom of two feeding hoppers to receive the proportionally mixed PMMA matrix and toughening masterbatch. Heating blocks are segmented on the outside of the fixed shell for gradient heating and melting of the material in different temperature zones. The drive motor of the screw conveyor is set to a low speed (e.g., 70 r / min) to reduce the damage to the heat-sensitive toughening agent molecular chains caused by high shear forces.

[0018] Calendering assembly: Located at the discharge end of the extrusion assembly, it is used to precisely roll-form the extruded molten sheet. Specifically, it includes a guide roller module and first, second and third rollers arranged in sequence to form a three-stage progressive calendering system.

[0019] This equipment structure enables continuous and automated production throughout the entire process, from online granulation and cooling screening of toughening masterbatch, to precise proportioning and low-temperature, low-speed melt blending with PMMA matrix, and finally to integrated calendering, ensuring process consistency and product quality stability.

[0020] Thirdly, the present invention provides a method for preparing impact-resistant, high-transmittance acrylic sheets using the above-mentioned equipment.

[0021] This method mainly includes the following steps: S1: Preparation of PMMA matrix with specific particle size: High-purity PMMA matrix with a particle size of 2.5-3.0 mm is obtained by bulk polymerization and gradient heating process.

[0022] S2: Online preparation of toughening masterbatch with specific particle size: The components of toughening masterbatch are fed into the pre-preparation component, extruded through a granulation screen, granulated, cooled online, and separated by liquid-solid separation to obtain toughening masterbatch particles with a particle size of 2.0-2.5mm, which are then directly conveyed to the feeding hopper A.

[0023] S3: Quantitative Mixing and Melt Extrusion: PMMA matrix (80-85 parts) and online-prepared toughening masterbatch (15-20 parts) are synchronously fed into the stationary shell of the extruder via a servo control system at a precise speed ratio (approximately 8:2). The screw conveyor operates at a low speed (e.g., 70 r / min), applying gentle shear mixing to the materials. Simultaneously, the stationary shell is heated in separate temperature zones along the extrusion direction (e.g., sequentially 190°C, 215°C, 225°C, 220°C), ensuring the materials are fully melted but not overheated during the blending process.

[0024] S4: Three-stage calendering: After being guided by the guide roller module, the extruded molten slab is progressively rolled through three rollers. The rollers of different widths can be replaced and the roller spacing can be adjusted according to the product specifications to finally obtain the sheet material with the target thickness and width.

[0025] S5: Finished Product Discharge: After the sheet material is cooled and shaped by calendering, it is discharged as the finished product.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. In this impact-resistant, high-transparency acrylic sheet and its extrusion and calendering equipment and process, the present invention combines a specific composite toughening masterbatch formula with precisely controlled particle size distribution, working synergistically with dedicated integrated equipment and processes. This successfully solves the material challenge of achieving both "high strength" and "high clarity" in automotive interior and exterior parts. The resulting sheet has a light transmittance of ≥92.5%, providing excellent optical clarity for in-vehicle display systems (such as dashboard light-transmitting panels); a simply supported beam impact strength of ≥15.5kJ / m², effectively resisting impacts from door closures and object collisions, ensuring the structural integrity and durability of components; and a haze of ≤0.45%, meeting the stringent requirements for a "high-end" and transparent surface appearance for decorative parts such as A-pillars and trim strips, avoiding visual blurring caused by toughening.

[0027] 2. In this impact-resistant high-transmittance acrylic sheet and its extrusion and calendering equipment and process, by strictly controlling the particle size of PMMA matrix (2.5-3.0mm) and toughening masterbatch (2.0-2.5mm) and the slight particle size difference (0.2-0.5mm), it is ensured that the two have similar fluidity, settling speed and heat-induced melting behavior when melt-blended. This eliminates material stratification, toughening agent agglomeration and phase separation from the source. This is the core mechanism for achieving high light transmittance and uniform toughening.

[0028] 3. In this impact-resistant, high-transparency acrylic sheet and its extrusion and calendering equipment and process, the equipment integrates online preparation, cooling, screening, and conveying functions of toughening masterbatch, realizing "on-demand preparation" and avoiding the storage, transportation, and uncontrollable particle size problems of traditional purchased masterbatch. Through the cooperation of dual feeding hoppers and servo motors, precise weight-based synchronous feeding of PMMA base particles and toughening masterbatch is achieved. Combined with low-speed (e.g., 70 r / min) spiral conveying and segmented gradient heating, the materials achieve molecular-level uniform mixing under gentle shearing and optimal melting temperature.

[0029] 4. In this impact-resistant, high-transparency acrylic sheet and its extrusion and calendering equipment and process, the toughening masterbatch components selected in this invention (pure acrylate, aliphatic polyether, pentaerythritol ester, etc.) are all polar or weakly polar compounds, exhibiting good compatibility with the PMMA matrix. They synergistically enhance low-temperature toughness, improve processing fluidity, and prevent thermal degradation and photo-oxidation, achieving a comprehensive and balanced improvement in the mechanical, optical, and weather-resistant properties of the sheet without significantly reducing the inherent advantages of PMMA. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the structure of the fixing shell of the present invention; Figure 3 This is a schematic diagram of the support platform of the present invention; Figure 4 This is a schematic diagram of the feeding tube of the present invention; Figure 5 This is a schematic diagram of the heating block of the present invention; Figure 6 This is a schematic diagram of the structure of the calendering box of the present invention; Figure 7 For the present invention Figure 6 Enlarged view of point A.

[0031] The meanings of the labels in the diagram are as follows: 1. Main body of production unit; 2. Calendering box; 3. Control panel; 4. Support platform; 5. Heating block; 6. Fixed shell; 7. Servo motor A; 8. Screw conveyor; 9. Feeding bucket A; 11. Servo motor B; 12. Agitating roller; 13. Conveying roller A; 14. Feed inlet A; 15. Feed inlet B; 16. Fixed base; 17. Servo motor C; 18. Screw conveyor; 19. Granulation screen; 20. Rotating toothed disc; 21. Scraper; 22. Drive tooth; 23. Feed inlet C; 24. Cooling pipe; 25. Separation box; 26. Separation screen; 27. DC motor; 28. Screw conveyor; 29. ​​Feeding pipe; 30. Pump pipe; 31. Discharge pipe; 32. Guide roller module; 33. First roller; 34. Second roller; 35. Third roller; 36. Plate outlet. Detailed Implementation

[0032] 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.

[0033] Example 1: Preparation of PMMA matrix 80–85 parts by weight of methyl methacrylate monomer, 0.07–0.09 parts by weight of azobisisobutyronitrile, an appropriate amount of n-butanethiol, and 0.001 parts by weight of hydroquinone were added to a reactor. The mixture was stirred at 80 rpm for 30 minutes at room temperature to ensure complete dissolution and homogeneity of all components. Subsequently, the reactor was evacuated to a vacuum of -0.09 MPa and held at this pressure for 15 minutes to thoroughly remove dissolved air and air bubbles from the monomer.

[0034] The reaction system was heated to 60°C and held at that temperature for 2.5 hours, while stirring at 80 rpm and monitoring the viscosity in real time. Heating was stopped when the viscosity of the mixture reached approximately 2000 Pa·s. The prepolymer mixture was then poured into a preheated flat mold for gradient polymerization. The polymerization program was as follows: 65°C for 4 hours, then heated to 75°C for 6 hours, and finally held at 85°C for 3 hours. Ventilation was maintained throughout the polymerization process to prevent localized overheating. After polymerization, the PMMA sheets were demolded and crushed and granulated. The granules were then sieved to obtain polymethyl methacrylate (PMMA) granules with a particle size of 2.5 mm to 3.0 mm.

[0035] Example 2: Online preparation of toughening masterbatch and board production This embodiment describes in detail the complete process of preparing acrylic sheets using the equipment of the present invention.

[0036] 2.1 Equipment Preparation and Start-up See Figure 1 The equipment is ready. First, inject clean circulating coolant (such as a water-ethylene glycol mixture) into the separation tank 25. Start the cooling system, and the coolant is pumped into the cooling pipe 24 through the pump pipe 30 to form a circulation loop. Feed the toughening masterbatch components described in Example 3 into the feed inlet C23 of the screw conveyor 18.

[0037] 2.2 Online Granulation of Toughening Masterbatch The servo motor C17 and drive gear 22 are started. The servo motor C17 drives the screw conveyor 18 to transport and pressurize the material forward. When the material is pushed to the granulation screen 19, it is squeezed into granules under pressure through the mesh. At the same time, the drive gear 22 drives the rotating toothed disc 20 to rotate, and the scraper 21 fixed to it rotates accordingly, scraping off the masterbatch particles attached to the outside of the granulation screen 19. The scraped masterbatch particles fall into the coolant in the cooling pipe 24 below, are rapidly cooled, and are flushed into the separation box 25 below with the coolant.

[0038] 2.3 Masterbatch Cooling and Separation The slurry entering the separation chamber 25 first impacts the inclined separation screen 26. The coolant flows back to the bottom of the separation chamber 25 through the mesh of the separation screen 26, while the solidified toughening masterbatch particles with a particle size of 2.0 mm to 2.5 mm are trapped on the separation screen 26.

[0039] The DC motor 27 is started, and its output drives the auger 28 to rotate. The auger 28 laterally conveys the toughening masterbatch particles trapped on the separating screen 26 to the feeding pipe 29. The feeding pipe 29 maintains a certain inclination angle and has a smooth inner wall. Under the action of gravity, the toughening masterbatch passes through the feeding pipe 29 and the inlet A14, directly and continuously entering a designated discharge bucket A9, completing the integrated process of "online preparation-cooling-screening-conveying" of the toughening masterbatch.

[0040] 2.4 Material Mixing and Extrusion The PMMA granules prepared in Example 1 with a particle size of 2.5-3.0 mm were fed into another parallel feeding bucket A9 through the feed inlet B15.

[0041] At this time, the servo motors B11 above the two feeding hoppers A9 are started. By precisely adjusting the speed ratio of the two servo motors B11 (set to 8:2 in this embodiment), the conveying rollers A13 at the bottom of the two feeding hoppers A9 rotate at the corresponding speed, thereby achieving the synchronous and uniform entry of PMMA matrix and online prepared toughening masterbatch into the fixed shell 6 below at the target weight ratio of 80-85:15-20 (i.e., about 8:2).

[0042] Subsequently, the servo motor A7 is started to drive the screw conveyor 8 to rotate at a low speed of 70 r / min. The purpose is to provide sufficient shear force to mix the materials while avoiding excessive shear heat and shear force, thereby protecting the toughening agent molecular structure from being damaged.

[0043] Simultaneously, multiple sets of heating blocks 5 provide segmented gradient heating to the fixed shell 6. Heat is transferred from the hopper towards the die head, with temperature settings such as: first segment (near the hopper) 190℃, second segment 215℃, third segment 225℃, and final segment (near the die head) 220℃. The die outlet temperature is maintained between 215℃ and 220℃. This gradient heating curve facilitates stable material heating, complete melting, and optimal mixing and homogenization in the melting segment. Under these mild blending conditions, PMMA matrix particles and toughening masterbatch with similar particle sizes achieve uniform dispersion at the molecular level, effectively preventing phase separation.

[0044] 2.5 Calendering The fully mixed and molten PMMA sheet blank, which is extruded from the end of the fixed shell 6 through the discharge pipe 31, enters the calendering box 2.

[0045] First, the billet passes through the guide roller module 32 for preliminary pre-rolling and directional alignment to ensure that the slab entering the main rolling zone has uniform thickness and is centered.

[0046] Next, the slab passes sequentially through the first pressure roller 33, the second pressure roller 34, and the third pressure roller 35, undergoing three stages of fine rolling. The roller gap at each stage can be precisely adjusted according to the thickness requirements of the final product. Furthermore, the lengths (i.e., working surface widths) of the first, second, and third pressure rollers can be selected and replaced according to the final sheet width specifications. Through this multi-stage adjustable rolling process, the thickness and width of the sheet are precisely controlled, resulting in uniform density and a high surface finish.

[0047] Finally, the formed acrylic sheet is discharged through the outlet 36 and enters the downstream cooling, traction and cutting processes to obtain the final impact-resistant and high-transmittance acrylic sheet product.

[0048] Example 3: Preparation of toughening masterbatch and polyether ester transparent antistatic agent The toughening masterbatch formulation of the present invention is as follows (based on 100 parts by weight of toughening masterbatch): 75 parts of methyl methacrylate (PMMA), 20 parts of acrylate, 3 parts of aliphatic polyether toughening agent, 0.6 parts of pentaerythritol ester (lubricant), 0.8 parts of phosphite ester (auxiliary antioxidant), 0.4 parts of benzophenone-based ultraviolet absorber, and 0.2 parts of lubricant.

[0049] Optional additions may include a transparent polyether ester antistatic agent. The following is an example of a specific preparation method for this antistatic agent and the all-acrylate in the toughening masterbatch: Preparation of transparent polyether ester antistatic agent: 100g caprolactam, 15g adipic acid, 60g polyethylene glycol (PEG), 5-15g glycidyl ether, and 1g zinc oxide were used as initial raw materials. First, 100g caprolactam, 15g adipic acid, and 1g zinc oxide were added to a three-necked flask, and nitrogen gas was introduced as a protective gas. The flask was heated under a nitrogen atmosphere, maintaining the reaction system temperature at 250℃ for 2 hours to prepare a bi-carboxyl-terminated polyamide prepolymer. Subsequently, 10g g glycidyl ether was added to the prepolymer, and the reaction temperature was controlled within the range of 230℃ to 250℃, with stirring for 4 hours. Afterward, a polycondensation reaction was carried out under high vacuum for 3 hours. Finally, the product was discharged and cooled to obtain a transparent sheet-like polyether ester antistatic agent.

[0050] Preparation of all-acrylate: 200 g of deionized water was added to the reactor. First, 0.48 g of sodium dodecylbenzene sulfate and 0.12 g of fatty alcohol polyoxyethylene ether were added to the reactor and stirred until completely dissolved, forming stable basic micelles. Next, 92 g of butyl acrylate, 1 g of ethylene glycol dimethacrylate (crosslinking agent), and 18 g of methacrylate were added to the reactor all at once. At this point, a pre-prepared mixture of ethylene glycol dimethacrylate and fatty alcohol polyoxyethylene ether was added dropwise to the reaction system at a precise rate of 0.1 g per minute to compensate for charge loss caused by monomer competitive adsorption. Then, while stirring at room temperature, ultrasonic treatment was applied to disperse and control the particle size of the latex particles, effectively preventing agglomeration. Next, the temperature inside the reactor was adjusted to 55°C to 60°C. 0.14 g of potassium persulfate (initiator) and 0.05 g of sodium bisulfite (accelerator) were added all at once to start the polymerization reaction. After the reaction has proceeded for 30 minutes, the remaining 0.06 g of potassium persulfate and 0.05 g of sodium bisulfite are added to the reaction system in three equal installments at regular time intervals. During this process, the addition rate is controlled by increasing the sampling frequency of the viscosity monitoring system to maintain a stable free radical concentration within the reaction system. Simultaneously, an intelligent temperature control system is activated to precisely control the reaction temperature fluctuation within ±0.5℃, and continuous stirring ensures uniform temperature within the reactor, preventing violent polymerization (explosive polymerization) caused by localized overheating. The entire heat preservation reaction stage lasts 1.5 to 2 hours. After the polymerization reaction is complete, the resulting emulsion is sent to a spray dryer for initial drying, followed by a secondary drying in a fluidized bed to finally obtain a powdered all-acrylate product.

[0051] Blending and granulation of toughening masterbatch: The polyether ester transparent antistatic agent prepared above (added according to the formula), all-acrylate powder, and other components (75 parts methyl methacrylate, 3 parts aliphatic polyether, 0.6 parts pentaerythritol ester, 0.8 parts phosphite, 0.4 parts benzophenone-based UV absorber, and 0.2 parts lubricant) are thoroughly premixed using a high-speed mixer (such as a high-speed agitator) according to the formula to ensure uniform distribution of each component powder. Subsequently, the mixed material is melt-extruded and underwater pelletized through a twin-screw extruder at a suitable screw speed and temperature range (e.g., 160℃-210℃). After cooling, dehydration, and sieving, toughening masterbatch with a particle size of 2.0 mm to 2.5 mm and uniform mixing of all components is obtained.

[0052] Example 4: Analysis of Acrylic Sheet Performance Test Results 1. Light transmittance performance Under normal temperature (25℃±2℃) and standard atmospheric pressure conditions, a 3mm thick sheet was tested using a 550nm visible light wavelength.

[0053] Data from this invention: Light transmittance is consistently ≥92.5% Comparative data: Light transmittance is only 89.5%~90.5% The core reason for the performance improvement: By precisely controlling the particle size difference (0.2~0.5mm) between PMMA matrix particles (2.5-3.0mm) and toughening masterbatch (2.0-2.5mm), combined with online precision granulation and rapid cooling processes, toughening agent agglomeration and phase separation defects caused by particle size / density differences are eliminated at the source. Simultaneously, a polarity-matched additive system (such as all-acrylate) significantly reduces light scattering at the phase interface, increasing light transmittance by more than 3%.

[0054] 2. Impact strength of simply supported beam (without notch) Tested on 3mm thick plates under normal temperature conditions and an impact velocity of 2.9m / s.

[0055] Data from this invention: Impact strength ≥ 15.5 kJ / m² Comparative data: Impact strength 8.5~10.0 kJ / m² The core reason for the performance improvement: The dual toughening mechanism works synergistically: 20 parts of all-acrylate "embedded" soften the PMMA molecular chain, enhancing matrix toughness; 3 parts of aliphatic polyether toughening agent improve low-temperature impact resistance. Particle size control technology ensures highly uniform dispersion of the toughening components, increasing impact strength by over 50%.

[0056] 3. Haze control capability Perform haze tests on 3mm plates without surface defects.

[0057] ‌Data of this invention: Haze ≤ 0.45% ‌Data of comparative example: Haze 0.8% - 1.0% ‌Core reason for performance improvement: The technical route of "ultrasonic dispersion + particle size control + online high-speed cooling granulation", combined with the built-in separation and screening mechanism of the equipment, almost completely eliminates the agglomeration of toughening agents. Low-speed spiral conveying (70r / min) and segmented gradient heating (190°C → 220°C) avoid high-shear degradation and reduce the generation of light scattering centers.

[0058] ‌4. Shore D hardness Measure the hardness of 3mm plates with a 15s indenter contact time.

[0059] ‌Data of this invention: Hardness ≥ 86 ‌Data of comparative example: Hardness 84 - 85 ‌Core reason for performance improvement: The total amount of additives is optimized to 4 - 5% of the total weight of the plate. On the premise that PMMA matrix particles are dominant (80 - 85 parts), it not only improves toughness but also maintains the rigidity of the polymer main chain, achieving a balance between hardness and toughness.

[0060] ‌5. Surface resistivity (antistatic property) Test the surface of clean plates in an environment with a humidity of 50% ± 5%.

[0061] ‌Data of this invention: ≤ 1.8×10¹¹Ω ‌Data of comparative example: ≥ 10¹ 4 Ω ‌Core reason for performance improvement: The in-situ added polyether ester antistatic agent migrates to the surface of the plate during melt blending, forming a continuous conductive network, reducing the resistivity by 3 orders of magnitude.

[0062] ‌6. Weather resistance (xenon lamp for 1000h) Detect the attenuation of light transmittance after accelerated aging with a 600W xenon lamp.

[0063] ‌Data of this invention: Light transmittance decrease ≤ 2.8% ‌Data of comparative example: Light transmittance decrease ≥ 4.5% (accompanied by yellowing) ‌Core reason for performance improvement: Aliphatic polyether toughening agents improve anti-aging ability, phosphite inhibits thermal-oxidative degradation, and benzophenone ultraviolet absorbers protect the main chain structure. The three form a synergistic protection system.

[0064] ‌7. Thickness tolerance control The thickness fluctuation was measured at 10 points on the target 3mm sheet material.

[0065] Data for this invention: Tolerance ≤ ±0.03mm Comparative data: Tolerance ≤ ±0.05mm The core reason for the performance improvement: The three-stage calendering system (guide rollers + three sets of pressure rollers) achieves a 40% improvement in thickness uniformity through progressive rolling and high-precision horizontal calibration.

[0066] 8. Melt Flow Rate (MFR) Stability Multiple parallel samples were tested at 230℃ / 2.16kg.

[0067] Data from this invention: Fluctuation value ≤ 0.3g / 10min Comparative data: fluctuation value ≤ 0.6g / 10min The core reason for the performance improvement: Pentaerythritol ester in toughening masterbatch optimizes melt flowability, segmented gradient heating (190℃→220℃) ensures stable thermal history, low-speed conveying reduces shear degradation, and MFR fluctuation is reduced by 50%.

[0068] Based on the above embodiments and performance tests, compared with the prior art, the impact-resistant high-transmittance acrylic sheet, its extrusion and calendering equipment and process of the present invention have the following advantages: By combining a specific composite toughening masterbatch formula with precisely controlled particle size distribution, and working synergistically with dedicated integrated equipment and processes, the material challenge of simultaneously achieving "high strength" and "high clarity" in automotive interior and exterior trim parts has been successfully solved. The resulting sheet material boasts a light transmittance of ≥92.5%, providing excellent optical clarity for in-vehicle display systems (such as dashboard light-transmitting panels); a simply supported beam impact strength of ≥15.5kJ / m², effectively resisting impacts from door closures and object collisions, ensuring the structural integrity and durability of components; and a haze of ≤0.45%, meeting the stringent requirements for a "premium" and transparent surface appearance for decorative components such as A-pillars and trim strips, avoiding visual blurring issues caused by toughening.

[0069] Through an innovative formula system, innovative core process, and innovative integrated equipment (online granulation, screening, and blending), the contradiction between toughening and light transmission, and between toughening and strength in traditional technologies has been resolved. This has enabled the sheet to achieve superior performance in key indicators such as light transmittance (≥92.5%), impact strength (≥15.5kJ / m²), and hardness (≥86) compared to traditional cast and ordinary extruded sheets, thus improving its overall performance and achieving a balance and transcendence of key properties.

[0070] The invention precisely defines the particle size of PMMA matrix (2.5-3.0 mm) and toughening masterbatch (2.0-2.5 mm) and their minute particle size difference of 0.2-0.5 mm. Combined with a mild and controllable online preparation and mixing environment formed by specialized equipment, it ensures the high consistency of gravity, flowability and melting behavior of different raw material components from a physical perspective. This reduces defects such as stratification, segregation and toughening agent agglomeration, which is the structural basis for obtaining high light transmittance and high toughness, and solves the problem of uneven dispersion at its root.

[0071] This equipment integrates the entire process from masterbatch granulation, screening, and conveying to batching, mixing, extrusion, and calendering, achieving highly efficient integrated operation from raw materials to semi-finished products to finished products. Through precise control methods such as dual servo motor synchronous proportioning, segmented gradient heating, low-speed extrusion (70 r / min), and three-stage calendering, it ensures the repeatability of the production process and the high stability of product quality, thereby improving the integration and stability of the production process.

[0072] By introducing a self-made polyether ester transparent antistatic agent, the board is endowed with excellent antistatic properties without affecting the light transmittance, thus expanding its application prospects in high-end fields such as precision electronics and cleanrooms.

[0073] In summary, this invention achieves systematic integration and innovation across four dimensions: formulation design, particle size control, equipment construction, and process parameters, providing a new path for the industrial-scale production of high-performance, multi-functional acrylic sheets.

[0074] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0075] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An impact-resistant, high-transmittance acrylic sheet, characterized in that, It is made from the following components in parts by weight: 80-85 parts of methyl methacrylate; Azobisisobutyronitrile (AIB) 0.07–0.09 parts; Hydroquinone 0.001 parts; 15-20 parts toughening masterbatch; The toughening masterbatch includes polymethyl methacrylate, acrylate, aliphatic polyether, pentaerythritol, phosphite, benzophenone-based UV absorbers, and lubricants. Furthermore, the particle size of the polymethyl methacrylate (PMMA) matrix constituting the acrylic sheet is 2.5 mm to 3.0 mm, the particle size of the toughening masterbatch is 2.0 mm to 2.5 mm, and the particle size difference between the PMMA matrix and the toughening masterbatch is 0.2 mm to 0.5 mm.

2. The impact-resistant, high-transmittance acrylic sheet according to claim 1, characterized in that: Based on the weight parts of the toughening masterbatch, its composition is as follows: 75 parts of methyl methacrylate; 20 parts of all-acrylate; 3 parts aliphatic polyether type; Pentaerythritol ester 0.6 parts; 0.8 parts of phosphite; 0.4 parts of benzophenone-based ultraviolet absorber; 0.2 parts of lubricant.

3. The impact-resistant, high-transmittance acrylic sheet according to claim 1, characterized in that: The toughening masterbatch also includes a polyether ester transparent antistatic agent.

4. The impact-resistant, high-transmittance acrylic sheet according to claim 1, characterized in that, The total weight of the full acrylate, the aliphatic polyether, the pentaerythritol ester, the phosphite, the benzophenone-based UV absorber, and the lubricant accounts for 4% to 5% of the total weight of the impact-resistant high-transmittance acrylic sheet.

5. An extrusion calendering apparatus for preparing impact-resistant, high-transmittance acrylic sheets as described in any one of claims 1 to 4, characterized in that, include: Main body of production equipment (1); A pre-preparation assembly is used to prepare toughening masterbatch particles of a specific particle size; the pre-preparation assembly includes a spiral conveying granulation unit, a cooling unit, and a separation conveying unit arranged in sequence. The dual feeding assembly is installed on the main body (1) of the production device and includes two feeding barrels A (9) arranged side by side. One feeding barrel A (9) is used to receive the polymethyl methacrylate granules, and the other feeding barrel A (9) is connected to the separation and conveying unit of the pre-prepared assembly through a feeding pipe (29) to receive the toughening masterbatch particles. Each of the two feeding barrels A (9) is provided with a controllable conveying roller A (13). The extrusion assembly includes a fixed shell (6) and a spiral conveyor (8) disposed therein, the fixed shell (6) being connected to the bottom of the two feeding hoppers A (9) to receive the mixed material; And a calendering assembly, located at the discharge end of the extrusion assembly, for performing multi-stage roll forming on the extruded material.

6. The impact-resistant, high-transparency acrylic sheet extrusion and calendering equipment according to claim 5, characterized in that, The spiral conveying granulation unit includes a feed inlet C (23), a spiral conveyor (18), a granulation screen (19), and a scraper assembly. The cooling unit includes a cooling pipe (24). The separation conveying unit includes a separation box (25), a separation screen (26), and an auger (28). The separation box (25) is connected to the cooling pipe (24), and the feeding pipe (29) is connected to the separation box (25).

7. The impact-resistant, high-transparency acrylic sheet extrusion and calendering equipment according to claim 5, characterized in that, The upper part of the two feeding buckets A (9) is respectively provided with a stirring roller (12) for stirring and preventing material bridging. The bottom of the stirring roller (12) is coaxially connected to the conveying roller A (13). The rotation of each conveying roller A (13) is driven by an independent servo motor B (11) to control the synchronous feeding ratio of the two materials.

8. The impact-resistant, high-transparency acrylic sheet extrusion and calendering equipment according to claim 5, characterized in that, The outer side of the fixed shell (6) of the extrusion assembly is provided with multiple sets of heating blocks (5) in sections. The bottom of the inner side of the main body (1) of the production device is fixedly connected to a support platform (4). The top of the outer side of the support platform (4) is fixedly connected to multiple sets of heating blocks (5). The drive servo motor A (7) of the spiral conveying rod (8) of the device body (1) is provided on one side (control panel 3) with a speed of 70 r / min. The calendering assembly includes a guide roller module (32) set in the calendering box (2) and a first roller (33), a second roller (34), and a third roller (35) arranged in sequence.

9. A method for preparing impact-resistant high-transparency acrylic sheets using an extrusion and calendering apparatus as described in any one of claims 5-8, characterized in that, Includes the following steps: S1: Prepare polymethyl methacrylate-based particles of a specific particle size; Methyl methacrylate monomer, azobisisobutyronitrile, n-butanethiol, and hydroquinone were added to a reactor, stirred, defoamed, heated, and polymerized. After demolding, the mixture was granulated to obtain polymethyl methacrylate granules with a particle size of 2.5 mm to 3.0 mm. S2: Use the extrusion and calendering equipment to prepare toughening masterbatch with a specific particle size online; Cooling liquid is injected into the separation box (25) of the pre-prepared component and circulated; each component of the toughening masterbatch is fed into the screw conveyor (18) through the feed port C (23), granulated by extrusion through the granulation screen (19), scraped off and fell into the cooling pipe (24) for cooling, and then separated by the separation screen (26) and conveyed to the feeding pipe (29) by the screw conveyor (28) to obtain toughening masterbatch with a particle size of 2.0 mm to 2.5 mm; S3: Quantitative mixing and melt extrusion; The polymethyl methacrylate granules prepared in step S1 are fed into one of the feeding buckets A (9) of the dual feeding assembly through the feed port B (15), and the toughening masterbatch prepared in step S2 is automatically fed into the other feeding bucket A (9); two sets of servo motors B (11) are started, and the rotational speed ratio of the two sets of conveying rollers A (13) is controlled to be 8:2, so that the polymethyl methacrylate granules and the toughening masterbatch enter the fixed shell (6) synchronously according to the corresponding weight ratio; the servo motor A (7) is started to drive the spiral conveyor rod (8) to rotate, and at the same time, the fixed shell (6) is heated in sections by the segmented heating blocks (5) so that the materials are fully melted and mixed before being extruded; S4: Calendering; After being guided by the guide roller module (32), the extruded molten material is subjected to three-stage roller pressing through the first roller (33), the second roller (34), and the third roller (35) in sequence. The roller spacing and model are adjusted to obtain a plate with the target thickness and width. S5: Finished product output, obtaining the impact-resistant, high-transparency acrylic sheet.

10. The impact-resistant, high-transmittance acrylic sheet according to claim 9, characterized in that, In step S3, the segmented heating temperatures of the fixed shell (6) are set sequentially along the material extrusion direction to 190°C, 215°C, 225°C, and 220°C, and the temperature at the mold outlet is controlled between 215°C and 220°C.

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