Lubricant composition for processing high-weather-resistance polycarbonate hollow plate and preparation method of lubricant composition

Abstract

The invention discloses a lubricant composition for processing a high-weather-resistance polycarbonate hollow plate and a preparation method of the lubricant composition, and belongs to the technical field of high polymer material processing aids. The lubricant composition for processing the high-weather-resistance polycarbonate hollow plate comprises the following raw material components in parts by mass: 40-60 parts of a main lubricant, 10-20 parts of an auxiliary lubricating flowable agent, 10-25 parts of a modified weather-resistant dispersion carrier, 2-5 parts of an auxiliary heat stabilizer and 1-3 parts of a weather-resistant reinforcing agent. The novel weather-resistant dispersion carrier is matched with the polycarbonate matrix in structural compatibility and polar interaction / interfacial compatibilization effect, so that the dispersity of the lubricant dispersion composition in the matrix is remarkably improved. Local gathering of the lubricating agent is effectively avoided, the defects of oil spots and cloud-like stripes on the surface of the hollow plate are thoroughly eliminated, and therefore the surface flatness and optical isolation of a product are greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of polymer processing aids technology, specifically relating to a lubricant composition for processing high weather-resistant polycarbonate hollow sheets and its preparation method. Background Technology

[0002] Polycarbonate (PC) hollow sheets inherit excellent light transmittance, impact resistance, and thermal insulation properties, and are widely used in architectural lighting, greenhouses, and advertising signage. During the processing of polycarbonate hollow sheets, the high viscosity of the polycarbonate melt often necessitates the addition of lubricants to improve flowability, lower processing temperature, and prevent material buildup in the mold. Currently, the industry commonly uses pentaerythritol stearate (PETS) as the primary lubricant, combined with auxiliary lubricants and dispersants to form a lubricant composition. Existing dispersants are mostly ordinary polycarbonate powder or low-polyethylene wax, whose main function is to act as a physical guide, assisting the lubricant in dispersing within the polycarbonate matrix. However, in the actual production of high-weather-resistant polycarbonate hollow sheets, existing technologies still have the following significant drawbacks: First, insufficient uniform dispersion. Traditional physical conformal carriers struggle to achieve complete compatibility between lubricants and the polycarbonate matrix on localized surfaces. During high-speed collisions, lubricant mixing can easily lead to localized aggregation, resulting in "oil spots" or hazy streaks on the product surface, severely impacting the optical interface and surface quality of the hollow board. Secondly, they exhibit poor weather resistance and processing stability. Although existing formulations often include large amounts of absorbents (such as benzotriazole compounds) or antioxidants, these additives are often merely physical additions to the lubrication system. During high-temperature processing, small-molecule additives are prone to oxidation, yellowing, or volatilization. Furthermore, during later use, absorbents easily migrate to the surface and are lost, shortening the weather resistance life of the hollow board. Finally, existing carriers have limited functionality. Most carriers only act as physical supports, lacking chemical bonding with the polycarbonate matrix and functional additives. They cannot simultaneously improve processing fluidity while providing auxiliary reinforcement for the long-term weather resistance of the product. Therefore, developing a dispersion carrier capable of achieving dispersion and possessing chemical characteristics to enhance weather resistance has become a pressing technical challenge in the polycarbonate hollow board processing field. Summary of the Invention

[0003] This invention aims to solve the technical problems of poor dispersion uniformity, easy formation of "oil spots," and insufficient weather resistance due to easy migration and loss of weather-resistant agents in the processing of polycarbonate hollow sheets in the prior art. It provides a lubricant composition and preparation method for processing high-weather-resistant polycarbonate hollow sheets. Uniform dispersion at the molecular / microscale is achieved through polar interactions and compatibilizer effects, and the migration tendency of additives is reduced, significantly improving the processing stability, optical structure, and long-term weather resistance of the hollow sheets.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The present invention provides a lubricant composition for processing high weather-resistant polycarbonate hollow boards, comprising the following raw material components in parts by weight: 40-60 parts of main lubricant, 10-20 parts of auxiliary lubricating flow agent, 10-25 parts of modified weather-resistant dispersion carrier, 2-5 parts of auxiliary heat stabilizer, and 1-3 parts of weather-resistant reinforcing agent; The modified weather-resistant dispersion carrier is prepared from polycarbonate oligomers, γ-aminopropyltriethoxysilane (KH-550), 2-(2'-hydroxy-5'-methylphenyl)benzotriazole (UV-BZT), polyethylene glycol 400 (PEG-400) and long-chain antioxidants; The long-chain antioxidant is 2,2-bis(((3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)oxy)methyl)propane-1,3-dimethyl distearate.

[0005] Furthermore, the primary lubricant is selected from at least one of pentaerythritol stearate (PETS), stearamide stearate (SSAm), and linoleic acid ester (HAE).

[0006] Furthermore, the auxiliary lubricating fluid is selected from at least one of stearamide (SA), erucamide (EA), ethylene bis-stearamide (EBS), calcium stearate (CaSt), and zinc stearate (ZnSt).

[0007] Furthermore, the auxiliary heat stabilizer is selected from at least one of tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168, TDP), pentaerythritol diphosphite (antioxidant 626), and pentaerythritol diphosphite (antioxidant 1330).

[0008] Furthermore, the weather-resistant reinforcing agent is selected from at least one of 2-(2'-hydroxy-3',5'-di-tert-pentylphenyl)benzotriazole (UV-328), 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole (UV-327), and 2-(2H-benzotriazole-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (UV-234).

[0009] Furthermore, the raw materials for preparing the modified weather-resistant dispersion carrier include, by weight, 70-80 parts of polycarbonate oligomer, 5-8 parts of γ-aminopropyltriethoxysilane, 6-9 parts of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 3-5 parts of polyethylene glycol 400, and 0.5-1 parts of long-chain antioxidant; the number average molecular weight of the polycarbonate oligomer is 1000-3000.

[0010] A method for preparing a lubricant composition for processing high weather-resistant polycarbonate hollow sheets includes the following steps: Premixing process: Mix the main lubricant, auxiliary lubricating flow agent, modified weather-resistant dispersion carrier, auxiliary heat stabilizer and weather-resistant reinforcing agent; Melt granulation process: The mixed materials are melted, extruded, and granulated using an extruder; Post-processing steps: Remove dust from the particles and dry them.

[0011] Furthermore, the modified weather-resistant dispersion carrier is prepared by the following steps: premixing polycarbonate oligomer, polyethylene glycol 400 and long-chain antioxidant to obtain a premix; adding the premix to an extruder, and adding γ-aminopropyltriethoxysilane and 2-(2'-hydroxy-5'-methylphenyl)benzotriazole through side feeding for melt mixing and dispersion treatment and extrusion granulation; drying the granulated particles; and pulverizing the dried particles.

[0012] Furthermore, in the preparation of the modified weather-resistant dispersion carrier, the extruder barrel temperature for melt mixing and dispersion treatment is 180-200℃ in zone one, 220-240℃ in zone two, and 230-250℃ in zone three, while the die head temperature is 220-230℃; the particle size after pulverization is 100-200 mesh.

[0013] Furthermore, the temperature of the premixing process is 40-60℃, and the mixing time is 20-40 minutes.

[0014] Furthermore, in the melt granulation process, the temperatures of each zone of the extruder are 160-180℃ in zone one, 190-210℃ in zone two, 200-220℃ in zone three, and 190-200℃ at the die head.

[0015] This invention systematically solves the technical problems of uneven lubricant dispersion, surface oil spots, and insufficient weather resistance during the processing of high-weather-resistant polycarbonate hollow sheets through a multi-component coupled design at three levels: chemical compatibility, structural synergy, and functional synergy. Specifically, the main lubricant and auxiliary lubricating flow agent form a synergistic effect of layered slip and interfacial friction reduction during the melt processing stage, significantly reducing the viscosity of the polycarbonate melt and stabilizing its flow behavior. At the same time, the introduced modified weather-resistant dispersion carrier, with polycarbonate oligomers as the skeleton, transforms the lubricant from a traditional physical dispersion to an interfacial compatibilized and stable state plus a molecular-level / fine dispersion state through the polar / hydrogen bonding interaction between silane and the system and interfacial wetting and compatibilization. This fundamentally inhibits the migration and local enrichment of the lubricant during high-speed extrusion, thereby eliminating oil spots and cloud-like streaks. Furthermore, benzotriazole weather-resistant components and long-chain antioxidants are directionally introduced and stably present in the carrier molecular chain, forming a synergistic antioxidant-UV-resistant system under high processing temperatures and subsequent light exposure. This system inhibits the thermo-oxidative degradation of polycarbonate on the one hand, and significantly reduces the volatilization and migration loss of small-molecule weather-resistant additives on the other. Thus, this invention achieves simultaneous improvement in processing stability, surface quality, and long-term weather resistance through the synergistic effect of lubrication, dispersion, thermal stability, and weather resistance enhancement, comprehensively solving the core problem of existing technologies that struggle to balance dispersibility and weather resistance.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention utilizes a novel weather-resistant dispersion carrier, leveraging its compact structure and polar interactions / interfacial compatibility with the polycarbonate matrix, to significantly improve the dispersibility of the lubricant dispersion composition within the matrix. This effectively prevents localized lubricant aggregation, completely eliminating "oil spots" and cloud-like streaks on the surface of the hollow board, thereby greatly enhancing the surface smoothness and optical isolation of the product.

[0017] 2. This invention achieves compatibilization and stabilization of weather-resistant additives, as well as reduced migration / volatilization due to interactions, solving the problems of easy volatility and migration of small molecule additives in traditional physical addition methods. This chemical approach endows polycarbonate hollow boards with excellent long-term anti-aging properties, effectively adsorbing yellowing and embrittlement during long-term outdoor use, and significantly extending the product's lifespan.

[0018] 3. This invention exhibits excellent processing and thermal stability. Through the synergistic effect of specific long-chain antioxidants and the lubrication system, it effectively inhibits thermal oxidative degradation during high-temperature oxidation, ensuring the color stability of the finished product. Simultaneously, it improves the dynamic balance of the lubrication system at the mold interface, significantly reducing material accumulation in the mold, extending the continuous production cycle, improving production efficiency, and reducing production costs. Attached Figure Description

[0019] Figure 1The NMR spectrum of 2,2-bis(((3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)oxy)methyl)propane-1,3-dimethyl distearate, the long-chain antioxidant of the present invention.

[0020] Figure 2 The infrared spectrum is a comparison of the modified weather-resistant dispersion carrier A1 prepared in Example 2 of this invention with the polycarbonate oligomer. Detailed Implementation

[0021] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely 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.

[0022] Preparation Example 1: Preparation of long-chain antioxidant: 2,2-bis(((3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)oxy)methyl)propane-1,3-dimethyl distearate: The chemical structure of 2,2-bis(((3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)oxy)methyl)propane-1,3-dimethyl distearate is as follows: .

[0023] Step 1: In a dry flask, add 5.00 g of pentaerythritol, 21.42 g of stearic acid, 0.21 g of p-toluenesulfonic acid monohydrate, and 50 mL of toluene as solvent. Install a Dean-Stark water separator at the mouth of the flask and connect a condenser. Raise the system temperature to 130 °C under a nitrogen atmosphere and react for 14 hours with stirring. After the reaction is complete, stop heating and cool the reaction solution to room temperature. After cooling, transfer the reaction solution to a separatory funnel. The sample was washed twice with 30 mL of saturated sodium bicarbonate aqueous solution, once with 30 mL of distilled water, and finally once with 30 mL of saturated brine. The organic phase was dried with anhydrous sodium sulfate for 30 minutes, and the desiccant was removed by filtration. The solvent toluene was removed by rotary evaporation of the filtrate under reduced pressure to obtain a crude product solid. The crude product was purified by silica gel column chromatography (eluent gradient: n-hexane to a mixed solution of n-hexane and ethyl acetate, with a volume ratio of 80:20). The target component was collected and evaporated to dryness. After vacuum drying, 15.97 g of pentaerythritol distearate was obtained.

[0024] The structure of pentaerythritol is: ; The structure of stearic acid is: ; The structure of pentaerythritol distearate is: .

[0025] MS+Na of pentaerythritol distearate + :691; NMR of pentaerythritol distearate 1 HNMR (Chloroform-d)δ: 4.17(s,4H),3.80(dd,2H),3.59(d,4H),2.30(t,4H),1.60(s,4H),1.37-1.20(m,56H),0.97-0.82(m,6H).

[0026] Step 2: In a dry flask, 15.97 g of pentaerythritol distearate, 14.62 g of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, and 240 ml of anhydrous toluene were added sequentially. 0.45 g of p-toluenesulfonic acid monohydrate was added with stirring. The system temperature was raised to 130 °C under a nitrogen atmosphere, and the reaction was carried out for 14 hours with stirring. After the reaction was complete, the mixture was cooled to room temperature, and the reaction solution was poured into a separatory funnel. The solution was washed twice with 100 ml of saturated sodium bicarbonate aqueous solution, and then once each with 100 ml of deionized water and 100 ml of saturated saline solution. The organic phase was dried over anhydrous sodium sulfate for 30 minutes and then filtered. The filtrate was rotary evaporated under reduced pressure to remove most of the toluene solvent, yielding the crude product. The crude product was purified by silica gel column chromatography using a gradient elution of a mixed solution of n-hexane and ethyl acetate (ratio from 10:1 to 5:1). The fraction containing the target product was collected, concentrated under reduced pressure, and dried under vacuum to finally obtain 19.47g of 2,2-bis(((3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)oxy)methyl)propane-1,3-dimethyl distearate.

[0027] The structure of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid is: .

[0028] MS+Na of 2,2-bis(((3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)oxy)methyl)propane-1,3-dimethyl distearate + :1211; NMR of 2,2-bis(((3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)oxy)methyl)propane-1,3-dimethyl distearate 1 HNMR (Chloroform-d)δ, such as Figure 1 As shown: 7.02(s,4H),5.08(s,2H,),4.12(s,8H),2.85(t,4H),2.60(t,4H),2.3 0(t,4H),1.58-1.62(m,4H),1.42(s,36H),1.25(m,56H),0.88(t,6H).

[0029] Preparation Example 2: Preparation of a modified weather-resistant dispersion carrier: 1) Weigh the following raw materials by weight: polycarbonate oligomer: 75 parts, number average molecular weight of 2000; γ-aminopropyltriethoxysilane: 6 parts; 2-(2'-hydroxy-5'-methylphenyl)benzotriazole: 7 parts; polyethylene glycol 400: 4 parts; long-chain antioxidant: 0.8 parts.

[0030] 2) Add polycarbonate oligomer, polyethylene glycol 400 and long-chain antioxidant into a high-speed mixer and premix for 20 minutes at 40°C and 900 r / min to obtain a premix.

[0031] 3) Transfer the premix to a twin-screw extruder, and simultaneously feed γ-aminopropyltriethoxysilane and 2-(2'-hydroxy-5'-methylphenyl)benzotriazole into the extruder barrel at a constant speed through a side feeder. Control the temperature of each section of the extruder barrel: Zone 1 190℃, Zone 2 230℃, Zone 3 240℃, and the die head temperature 225℃. The screw speed is 65 r / min, and the residence time is 75 minutes. Perform melt mixing and compatibilization treatment reaction and then extrude and granulate.

[0032] 4) Place the extruded granules in a vacuum drying oven and dry them for 5 hours at a temperature of 90℃ and a vacuum degree of -0.09MPa.

[0033] 5) The dried particles are pulverized to a particle size of 150 mesh by an ultra-micro pulverizer to obtain modified weather-resistant dispersion carrier A1.

[0034] Infrared spectra of modified weather-resistant dispersion carrier A1 and polycarbonate oligomers are shown below. Figure 2 As shown, approximately 1770cm -1 A strong absorption peak for the carbonate group C=O appears at 1220-1180 cm⁻¹. -1 and approximately 1100cm -1 The surrounding area is absorbed by the stretching vibrations of carbonate (COC), approximately 1600 cm. -1 and 1500cm -1 Absorption due to aromatic ring skeletal vibration, 2960 cm⁻¹ -1 and 2870cm -1 The vicinity exhibits aliphatic CH stretching vibrations; compared to unmodified polycarbonate oligomers, the modified weather-resistant dispersion carrier shows improved performance at approximately 3400 cm⁻¹.-1 A broad peak appears / enhances at 1100-1030 cm⁻¹ (-OH / -NH stretching vibration). -1 The absorption region is significantly enhanced (due to the superposition of Si-O-Si / Si-OC and CO vibrations in PEG), and is particularly strong in the 800-850 cm⁻¹ region. -1 Silane-related absorption is observed, along with 2920 / 2850 cm⁻¹. -1 -CH2- absorption is enhanced and occurs at approximately 1735 cm⁻¹ -1 The presence of shoulder peaks or weak peaks of ester group C=O indicates the success of silane grafting and the introduction of weather-resistant additives / PEG.

[0035] Preparation Example 3: Preparation of a modified weather-resistant dispersion carrier: 1) Weigh the following raw materials by weight: polycarbonate oligomer: 70 parts, number average molecular weight of 2000; γ-aminopropyltriethoxysilane: 5 parts; 2-(2'-hydroxy-5'-methylphenyl)benzotriazole: 6 parts; polyethylene glycol 400: 3 parts; long-chain antioxidant: 0.5 parts.

[0036] 2) Add polycarbonate oligomer, polyethylene glycol 400 and long-chain antioxidant into a high-speed mixer and premix for 15 minutes at 30°C and 800 r / min to obtain a premix.

[0037] 3) Transfer the premix to a twin-screw extruder, add silane and benzotriazole to the side feed, and control the extruder temperature as follows: Zone 1 180℃, Zone 2 220℃, Zone 3 230℃, Die head temperature 220℃, screw speed 50r / min, residence time 60 minutes.

[0038] 4) The particles were dried at 80℃ and under a vacuum of -0.08MPa for 4 hours.

[0039] 5) Pulverize to 100 mesh to obtain modified weather-resistant dispersion carrier A2.

[0040] Preparation Example 4: Preparation of a modified weather-resistant dispersion carrier: 1) Weigh the following raw materials by weight: polycarbonate oligomer: 80 parts, number average molecular weight of 2000; γ-aminopropyltriethoxysilane: 8 parts; 2-(2'-hydroxy-5'-methylphenyl)benzotriazole: 9 parts; polyethylene glycol 400: 5 parts; long-chain antioxidant: 1 part.

[0041] 2) Premixing conditions: temperature 50℃, rotation speed 1000r / min, time 30 minutes.

[0042] 3) Extruder temperature: Zone 1 200℃, Zone 2 240℃, Zone 3 250℃, Die head temperature 230℃, Screw speed 80r / min, Residence time 90 minutes.

[0043] 4) Drying conditions: Dry at 100℃ and -0.1MPa vacuum for 6 hours.

[0044] 5) Pulverize to 200 mesh to obtain modified weather-resistant dispersion carrier A3.

[0045] Comparative preparation example 1: This preparation example is used to prepare a modified weather-resistant dispersion carrier. The preparation method is the same as that of Preparation Example 2, except that no long-chain antioxidant is added. The other raw material ratios and preparation processes are exactly the same as those of Preparation Example 2, and comparative carrier B1 is obtained.

[0046] Comparative preparation example 2: This preparation example is used to prepare a modified weather-resistant dispersion carrier. The preparation method of Preparation Example 2 is used, except that the long-chain antioxidant is replaced with antioxidant 1010. The other raw material ratios and preparation processes are exactly the same as those in Preparation Example 2, and comparative carrier B2 is obtained.

[0047] Comparative preparation example 3: This preparation example is used to prepare a modified weather-resistant dispersion carrier. The preparation method of Preparation Example 2 is used, except that the long-chain antioxidant is replaced with antioxidant BHT. The other raw material ratios and preparation processes are exactly the same as those in Preparation Example 2, and comparative carrier B3 is obtained.

[0048] Comparative preparation example 4: This preparation example is used to prepare a modified weather-resistant dispersion carrier. The preparation method of Preparation Example 2 is the same as that of Preparation Example 2 except that γ-aminopropyltriethoxysilane is not added. The other raw material ratios and preparation processes are exactly the same as those of Preparation Example 2, and comparative carrier B4 is obtained.

[0049] Example 1: A lubricant composition for processing high weather-resistant polycarbonate hollow sheets, comprising the following raw material components (by weight): Primary lubricant (pentaerythritol stearate, PETS): 50 parts; Auxiliary lubricating fluid (ethylene bis-stearamide, EBS): 15 parts; Modified weather-resistant dispersion carrier A1: 18 parts; Auxiliary heat stabilizer (tris(2,4-di-tert-butylphenyl) phosphite, antioxidant 168): 3.5 parts; Weather resistance enhancer (2-(2'-hydroxy-3',5'-di-tert-pentylphenyl)benzotriazole, UV-328): 2 parts.

[0050] Preparation method: 1) Premixing process: Put the above components into a high-speed mixer and mix for 30 minutes at a temperature of 50℃ and a speed of 650r / min; 2) Melt granulation process: The mixture is fed into a twin-screw extruder, and the temperature is controlled as follows: Zone 1 170℃, Zone 2 200℃, Zone 3 210℃, and Die head 195℃. The screw speed is 50r / min, and the mixture is extruded and granulated. 3) Post-processing: After dust removal by cyclone separation, the product is dehumidified and dried at 60°C for 4 hours, and then packaged to obtain the finished lubricant composition.

[0051] Example 2: A lubricant composition for processing high weather-resistant polycarbonate hollow sheets, referring to the raw material composition and preparation method of Example 1, except that the modified weather-resistant dispersion carrier A1 is replaced with the modified weather-resistant dispersion carrier A2, and the rest remains the same as in Example 1.

[0052] Example 3: A lubricant composition for processing high weather-resistant polycarbonate hollow sheets, referring to the raw material composition and preparation method of Example 1, except that the modified weather-resistant dispersion carrier A1 is replaced with the modified weather-resistant dispersion carrier A3, and the rest remains the same as in Example 1.

[0053] Example 4: A lubricant composition for processing high weather-resistant polycarbonate hollow sheets, comprising the following raw material components (by weight): The raw material components are as follows: Main lubricant (same as in Example 1): 60 parts; Auxiliary lubricating fluid (same as in Example 1): 20 parts; Modified weather-resistant dispersion carrier A1: 25 parts; Auxiliary heat stabilizer (same as in Example 1): 5 parts; Weather resistance enhancer (same as Example 1): 3 parts.

[0054] The preparation method is the same as in Example 1, except that the premixing temperature is 60°C and the temperature of the first zone of the extruder is 180°C.

[0055] Comparative Example 1: A lubricant composition for processing high weather-resistant polycarbonate hollow sheets, referring to the raw material composition and preparation method of Example 1, except that the modified weather-resistant dispersion carrier A1 is replaced with the modified weather-resistant dispersion carrier B1, and the rest remains the same as in Example 1.

[0056] Comparative Example 2: A lubricant composition for processing high weather-resistant polycarbonate hollow sheets, referring to the raw material composition and preparation method of Example 1, except that the modified weather-resistant dispersion carrier A1 is replaced with the modified weather-resistant dispersion carrier B2, and the rest remains the same as in Example 1.

[0057] Comparative Example 3: A lubricant composition for processing high weather-resistant polycarbonate hollow sheets, referring to the raw material composition and preparation method of Example 1, except that the modified weather-resistant dispersion carrier A1 is replaced with the modified weather-resistant dispersion carrier B3, and the rest remains the same as in Example 1.

[0058] Comparative Example 4: A lubricant composition for processing high weather-resistant polycarbonate hollow sheets, referring to the raw material composition and preparation method of Example 1, except that the modified weather-resistant dispersion carrier A1 is replaced with the modified weather-resistant dispersion carrier B4, and the rest remains the same as in Example 1.

[0059] Performance testing: 1. Sample Preparation: First, the lubricant compositions of the examples and comparative examples were added to high weather-resistant polycarbonate resin with a number-average molecular weight of 20,000-30,000 at a ratio of 0.8% by mass of PC resin, and thoroughly mixed. Polycarbonate hollow sheets were extruded using a twin-screw extruder, with uniform specifications: thickness 10mm, width 500mm, and a triangular ribbed hollow structure. The extrusion process parameters were as follows: extruder zone temperatures: Zone 1 180℃, Zone 2 230℃, Zone 3 250℃, Zone 4 260℃, die head temperature 255℃; screw speed: 45r / min; traction speed: 2.5m / min; cooling water temperature: 25±2℃. Test samples were cut from the middle area of ​​the formed hollow sheet (avoiding the edge by 50mm). All samples were placed at a constant temperature and humidity of 23±2℃ and 50±5%RH for 24 hours before testing.

[0060] 2. Dispersion and Surface Defect Test: Under natural light (illuminance 800-1000 lx), place the hollow board sample flat and observe surface defects such as "oil spots" and "cloudy streaks" at a distance of 50 cm from the sample. Rate them according to the following standards: Grade 0: No oil spots or cloud-like patterns, smooth and uniform surface; Level 1: Very slight cloud-like texture, only visible at close range (within 30cm), no oil spots; Level 2: Obvious cloud-like patterns or a small number (≤3 per m) 2 Fine oil spots (diameter ≤ 0.5 mm); Level 3: Severe or numerous cloud-like patterns (>3 / m) 2 Oil spots (diameter > 0.5 mm) are shown in Table 1.

[0061] 3. Using a roughness tester (stylus type), according to ISO4287-2022 standard, 10 test points were randomly selected on the sample surface (the distance between each point is ≥2cm) to test Ra (arithmetic mean roughness), and the average value was taken. The data are shown in Table 1.

[0062] 4. Weather resistance test: Placed in a xenon lamp aging test chamber, aging conditions are: irradiation intensity 0.51W / m 2 (At 340nm wavelength); Blackboard temperature: 65±3℃; Relative humidity: 60±5%RH; Aging cycle: 2000h; According to ISO21920-2:2021 standard, the CIELab values ​​of the samples before and after aging were tested using a colorimeter, and the total color difference ΔE was calculated. ab, the data is shown in Table 1.

[0063] Table 1 Examples 1-4 all exhibited a surface defect level of 0 and extremely low Ra values, demonstrating excellent surface smoothness. In contrast, Comparative Example 4, which lacked a key component, resulted in physical aggregation of the lubricant in the matrix due to the absence of silane's interfacial compatibilizing and polar effects. This led to the formation of obvious "oil spots" or "cloudy streaks" (defect level predicted as 3) on the product surface. The presence of these surface defects also significantly increased its roughness Ra.

[0064] Comparative Example 1, lacking long-chain antioxidants, exhibited the highest color difference after aging. Lacking effective thermal stability protection, the PC matrix underwent severe thermo-oxidative degradation during high-temperature processing and subsequent light exposure. Comparative Examples 2 and 3 used the general-purpose antioxidant 1010 and BHT, respectively. While showing improvement over Comparative Example 1, they were still significantly inferior to the examples. BHT, in particular, exhibited the worst weather resistance due to its small molecular weight, volatility, and susceptibility to a "pink discoloration" reaction. The examples used specific long-chain antioxidants with large molecular weights, strong migration resistance, and the ability to be chemically stabilized on the carrier molecular chains, effectively preventing the loss of additives. Therefore, the examples showed a color difference of only about 1.2-1.3 after 2000 hours of aging, maintaining excellent optical performance.

[0065] 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. A lubricant composition for processing high weather-resistant polycarbonate hollow sheets, characterized in that, The raw material components include the following parts by weight: 40-60 parts of main lubricant, 10-20 parts of auxiliary lubricating flow agent, 10-25 parts of modified weather-resistant dispersion carrier, 2-5 parts of auxiliary heat stabilizer, and 1-3 parts of weather-resistant reinforcing agent; The modified weather-resistant dispersion carrier is prepared from polycarbonate oligomers, γ-aminopropyltriethoxysilane, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, polyethylene glycol 400 and long-chain antioxidants; The long-chain antioxidant is 2,2-bis(((3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)oxy)methyl)propane-1,3-dimethyl distearate.

2. The lubricant composition for processing high weather-resistant polycarbonate hollow sheets according to claim 1, characterized in that, The primary lubricant is selected from at least one of pentaerythritol stearate, stearamide stearate, and lycine ester.

3. The lubricant composition for processing high weather-resistant polycarbonate hollow sheets according to claim 1, characterized in that, The auxiliary lubricating fluid is selected from at least one of stearamide, erucamide, ethylene bis-stearamide, calcium stearate, and zinc stearate.

4. The lubricant composition for processing high weather-resistant polycarbonate hollow sheets according to claim 1, characterized in that, The auxiliary heat stabilizer is selected from at least one of tris(2,4-di-tert-butylphenyl) phosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, and bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite. The weather-resistant enhancer is selected from at least one of 2-(2'-hydroxy-3',5'-di-tert-pentylphenyl)benzotriazole, 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole, and 2-(2H-benzotriazole-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol.

5. The lubricant composition for processing high weather-resistant polycarbonate hollow sheets according to claim 1, characterized in that, The raw materials for preparing the modified weather-resistant dispersion carrier include, by weight, 70-80 parts of polycarbonate oligomer, 5-8 parts of γ-aminopropyltriethoxysilane, 6-9 parts of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 3-5 parts of polyethylene glycol 400, and 0.5-1 parts of long-chain antioxidant; the number average molecular weight of the polycarbonate oligomer is 1000-3000.

6. A method for preparing a lubricant composition for processing high weather-resistant polycarbonate hollow sheets as described in any one of claims 1-5, characterized in that, Includes the following steps: Premixing process: Mix the main lubricant, auxiliary lubricating flow agent, modified weather-resistant dispersion carrier, auxiliary heat stabilizer and weather-resistant reinforcing agent; Melt granulation process: The mixed materials are melted, extruded, and granulated using an extruder; Post-processing steps: Remove dust from the particles and dry them.

7. The method for preparing the lubricant composition for processing high weather-resistant polycarbonate hollow sheets according to claim 6, characterized in that, The modified weather-resistant dispersion carrier is prepared by the following steps: premixing polycarbonate oligomer, polyethylene glycol 400 and long-chain antioxidant to obtain a premix; adding the premix to an extruder, and adding γ-aminopropyltriethoxysilane and 2-(2'-hydroxy-5'-methylphenyl)benzotriazole through side feeding to carry out a melt grafting reaction and extrusion granulation; drying the granulated particles; and crushing the dried particles.

8. The method for preparing the lubricant composition for processing high weather-resistant polycarbonate hollow sheets according to claim 7, characterized in that, In the preparation of the modified weather-resistant dispersion carrier, the extruder barrel temperature for the melt grafting reaction is 180-200℃ in zone one, 220-240℃ in zone two, and 230-250℃ in zone three, while the die head temperature is 220-230℃; the particle size after pulverization is 100-200 mesh.

9. The method for preparing the lubricant composition for processing high weather-resistant polycarbonate hollow sheets according to claim 6, characterized in that, The temperature of the premixing process is 40-60℃, and the mixing time is 20-40 minutes.

10. The method for preparing the lubricant composition for processing high weather-resistant polycarbonate hollow sheets according to claim 6, characterized in that, In the melt granulation process, the temperatures of each zone of the extruder are 160-180℃ in zone one, 190-210℃ in zone two, 200-220℃ in zone three, and 190-200℃ at the die head.

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