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

Abstract

The invention discloses a processing lubricant composition for a high-weather-resistance polycarbonate hollow plate and a preparation method of the processing lubricant composition, and relates to the technical field of high polymer material modification and processing aids. The invention relates to a processing lubricant composition for a high-weather-resistant polycarbonate hollow plate. The processing lubricant composition is prepared from the following raw materials in parts by mass: 20 to 45 parts of a weather-resistant internal lubricant, 10 to 25 parts of a weather-resistant external lubricant, 2 to 10 parts of a low-migration smooth component, 0.3 to 2.0 parts of an anti-dripping thermal stability synergist, 0.5 to 6 parts of a weather-resistant stable component and 8 to 25 parts of a modified siloxane graft. And 20-55 parts of a dispersion phase. According to the invention, a modified siloxane graft containing a specific active functional group and a polycarbonate compatible chain segment is introduced, and a chemical anchoring mechanism is utilized, so that a lubricating component and a PC molecular chain are subjected to in-situ chemical bonding in a processing process. The problem that a traditional micromolecular lubricant is prone to migration and precipitation is solved, the atomization phenomenon on the surface of the hollow plate is effectively avoided, the long-term light transmittance of the plate is kept, and the mold cleaning period of an extrusion mold is remarkably prolonged.

Description

Technical Field

[0001] This invention relates to the field of polymer material modification and processing aids, specifically to a processing lubricant composition for high weather-resistant polycarbonate hollow boards and its preparation method. Background Technology

[0002] Polycarbonate (PC) hollow sheets, commonly known as sun sheets, are widely used in building skylights, agricultural greenhouses, highway sound barriers, and interior decoration due to their excellent light transmittance, high impact strength, good thermal insulation properties, and lightweight and easy installation. However, because polycarbonate molecules have relatively rigid chains, high melt viscosity, and relatively poor fluidity, and because the processing and molding temperatures are typically high (generally between 230 and 300°C), significant frictional resistance exists between the melt and the screw, barrel, and die flow channels during extrusion production, especially in the molding of complex multi-layer hollow structures. This not only leads to excessively high extrusion pressure and increased energy consumption but also easily causes quality defects such as difficulty in demolding, flow marks, clouding, or decreased surface smoothness.

[0003] To improve the processing rheology and release properties of polycarbonate, the industry typically adds processing lubricants to the resin. Existing lubricant systems mainly include fatty acid esters, fatty acid amides, polyethylene waxes, and traditional silicone oils. However, these existing technologies have significant drawbacks in practical applications: First, traditional small-molecule lubricants have limited compatibility with polycarbonate matrices and lack effective anchoring mechanisms. During high-temperature, high-shear extrusion processes or long-term storage and use of products, lubricant molecules easily migrate to the surface of the sheet. This "precipitation" phenomenon not only causes oil mist or white frost on the sheet surface, severely affecting the product's light transmittance and visual clarity, but also causes the precipitated low-molecular-weight substances to continuously accumulate at the die orifice, forming carbon deposits or dirt, forcing frequent production line shutdowns for cleaning, greatly reducing production efficiency and increasing maintenance costs.

[0004] Secondly, polycarbonate hollow sheets are mainly used in outdoor environments, where they are exposed to strong ultraviolet radiation and humid heat for extended periods. Many traditional lubricants have poor thermal stability and weather resistance, making them prone to degradation and discoloration during high-temperature processing, or inducing photo-oxidation reactions in the polycarbonate molecular chains during outdoor use, accelerating yellowing and embrittlement of the sheets, thus significantly shortening the product's lifespan.

[0005] Furthermore, using external lubricants such as high-viscosity dimethyl silicone oil solely for the purpose of achieving good mold release often leads to stress concentration due to uneven dispersion or poor compatibility, thereby impairing the impact resistance and interlayer bonding of the hollow board. Therefore, developing a processing lubricant composition that provides efficient lubrication and excellent mold release properties, while also exhibiting extremely low migration, superior weather resistance, and good compatibility with the polycarbonate matrix, has become a pressing technical challenge in the current manufacturing field of high-performance polycarbonate hollow boards. Summary of the Invention

[0006] The main objective of this invention is to overcome the shortcomings of existing lubricants, such as easy migration and atomization, insufficient weather resistance, and poor processing thermal stability, and to provide a high-weather-resistant polycarbonate hollow board processing lubricant composition and its preparation method. This invention achieves chemical anchoring through the synergistic effect of its components, particularly by utilizing modified components containing polycarbonate-compatible segments and active functional groups. This imparts excellent processing fluidity and release properties to polycarbonate while fundamentally solving the problems of surface atomization and mold contamination caused by lubricant precipitation. Furthermore, it significantly improves the light transmittance retention, thermal stability, and outdoor weather resistance of the finished hollow board product.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: a processing lubricant composition for high weather-resistant polycarbonate hollow boards, the raw materials of which include the following components in parts by weight: 20-45 parts of weather-resistant internal lubricant; 10-25 parts of weather-resistant external lubricant; 2-10 parts of low-migration slippery component; Anti-drip heat stabilizer 0.3-2.0 parts; 0.5-6 parts of weather-stabilizing component; 8-25 parts of modified siloxane graft; Dispersed phase 20-55 parts; The modified siloxane graft compound is prepared from the following raw materials in parts by weight: 35-55 parts of reactive terminal siloxane, 20-45 parts of siloxane grafting precursor, 0.05-0.50 parts of reaction control system, 0.10-0.80 parts of neutral stabilizer, and 10-25 parts of diluent. The neutral stabilizer is .

[0008] Furthermore, the weather-resistant internal lubricant is selected from at least one of pentaerythritol stearate, glyceryl monostearate, stearamide stearate, and stearamide.

[0009] Furthermore, the weather-resistant external lubricant is selected from at least one of the following: polyethylene wax, oxidized polyethylene wax, montan wax, stearic acid, and calcium stearate.

[0010] Furthermore, the low-migration slippery component is selected from at least one of: polytetrafluoroethylene micro powder, polyvinylidene fluoride powder, and perfluoropolyether.

[0011] Furthermore, the anti-dripping heat-stabilizing synergist is selected from at least two of the following: hindered phenolic antioxidant 1010, hindered phenolic antioxidant 1076, phosphite antioxidant 168, and phosphite antioxidant 626, with a mass ratio of 1:1.

[0012] Furthermore, the weather-stabilizing component is selected from at least one of the following: UV absorber UV-326, UV absorber UV-329, UV absorber UV-531, hindered amine light stabilizer 770, and hindered amine light stabilizer 622.

[0013] Furthermore, the dispersed phase is selected from at least one of the following: polycarbonate powder, polycarbonate and polyethylene terephthalate copolyester, and polycarbonate and polyethylene terephthalate copolyester.

[0014] Furthermore, the reactive terminal siloxane is selected from at least one of the following: single-terminated glycidyl ether polydimethylsiloxane, double-terminated glycidyl ether polydimethylsiloxane, single-terminated aminopropyl polydimethylsiloxane, and double-terminated aminopropyl polydimethylsiloxane.

[0015] Furthermore, the siloxane grafting precursor is selected from: amino-modified polysiloxanes with -RNH2 in the side chain, specifically: KF-393 and KF-859 (Shin-Etsu Chemical).

[0016] Furthermore, the structure of the siloxane grafting precursor is as follows: The Organic group is -RNHR'NH2.

[0017] Furthermore, the reaction regulation system includes a catalyst and an inhibitor; Furthermore, the catalyst is selected from at least one of: dibutyltin dilaurate, stannous octoate, triethylamine, and triethylenediamine; Furthermore, the inhibitor is selected from at least one of calcium stearate, epoxidized soybean oil, and triphenyl phosphite; Furthermore, the diluent is selected from at least one of the following: dioctyl sebacate, diisodecyl adipate, polyethylene glycol dimethyl ether, and polypropylene glycol dimethyl ether.

[0018] Furthermore, the preparation method of the modified siloxane graft is as follows: under inert gas protection, the reactive terminal siloxane, the siloxane grafting precursor and the diluent are added to a reaction vessel, heated to 90-120℃ and stirred evenly at 300-500 rpm; then the reaction control system is added, and the coupling grafting reaction is carried out at 100-115℃ for 1-3 hours; after the reaction is completed, the neutral stabilizer is added to terminate the side reaction, and stirring is continued for 30-50 minutes. After cooling to room temperature, the mixture is filtered through a filter screen to obtain the modified siloxane graft.

[0019] A method for preparing a processing lubricant composition for high weather-resistant polycarbonate hollow boards includes the following steps: 1) Premixing: According to the mass ratio, the weather-resistant internal lubricant, weather-resistant external lubricant, low-migration slip component, anti-drip heat stabilizer synergist, weather-resistant stabilizing component, modified siloxane graft and dispersed phase are put into a high-pressure mixer for mixing to obtain a premix; 2) Melt extrusion: The premixed material is added to a twin-screw extruder for melt granulation; 3) Cooling and pelletizing: After the extrudate is cooled in a water cooling tank, it is pelletized by a pelletizer and dried to obtain the processing lubricant composition for high weather-resistant polycarbonate hollow boards.

[0020] Furthermore, the mixing conditions described in step 1) are: temperature 40 to 60°C, rotation speed 800 to 1200 revolutions per minute, and mixing time 10 to 20 minutes.

[0021] Furthermore, in step 2), the temperature settings for each zone of the twin-screw extruder are as follows: Zone 1 180 to 200°C, Zone 2 210 to 230°C, Zone 3 230 to 250°C, Zone 4 240 to 260°C, Zone 5 240 to 260°C, and the die head temperature 230 to 250°C; the screw speed is controlled at 200 to 400 revolutions per minute.

[0022] Furthermore, the drying conditions described in step 3) are: drying at 80 to 100°C for 3 to 5 hours.

[0023] This invention provides a high-weather-resistant processing lubricant composition for polycarbonate hollow boards, comprising internal and external dual lubrication, a low-migration slippery framework, chemically anchored siloxanes, thermal / photochemical dual stabilization, and a dispersion carrier. This composition addresses issues encountered during PC hollow board extrusion, such as high friction and pressure, flow marks, uneven demolding, and problems caused by migration and precipitation of traditional lubricants leading to atomization, mold contamination, and yellowing and embrittlement due to insufficient weather resistance. On one hand, the weather-resistant internal lubricant preferentially penetrates the melt to reduce internal friction between chain segments / particles, while the weather-resistant external lubricant forms a stable slip layer at the melt-metal interface. Together, these components significantly reduce extrusion resistance and pressure, decrease flow marks, and improve demolding and surface gloss. Simultaneously, the introduction of low-migration slippery components provides a more inert, shear-resistant slippery phase, enhancing long-term low-friction and anti-adhesion capabilities, and reducing the tendency for carbon / fouling induced by low-molecular-weight accumulation at the die. Modified siloxane grafts containing active functional groups and PC-compatible segments trigger chemical anchoring during high-temperature, high-shear processing, enabling lubrication-related components to bond / anchor in situ with the PC molecular chain. This fundamentally blocks the pathways of traditional small-molecule lubricants due to poor compatibility, thereby maintaining long-term light transmittance and extending the mold clearing cycle. Regarding stability, the anti-dripping thermal stabilizer synergistically works with the neutral stabilizer in the graft to capture free radicals / decompose peroxides while passivating side reaction active sites, thus inhibiting the thermal degradation and hydrolysis of PC under high-temperature shear, preventing discoloration and mechanical degradation. Furthermore, the weather-resistant stabilizing components are microscopically compounded with the modified siloxane grafts to construct a multi-dimensional light protection network, improving UV shielding / absorption efficiency, inhibiting yellowing and embrittlement caused by photo-oxidation, and meeting the outdoor service requirements of hollow boards. The dispersed phase, acting as a carrier, works in conjunction with the grafted material to create a stable and uniform micro-dispersion of the aforementioned additives in a high-viscosity PC system. This avoids stress concentration and performance inhomogeneity caused by agglomeration, thereby solving the technical problem.

[0024] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention introduces modified siloxane grafts containing specific active functional groups and polycarbonate-compatible segments, utilizing a chemical anchoring mechanism to enable in-situ chemical bonding between the lubricating component and the PC molecular chain during processing. This solves the problem of easy migration and precipitation of traditional small-molecule lubricants, effectively avoids fogging on the surface of hollow boards, maintains the long-term light transmittance of the board, and significantly extends the mold cleaning cycle of the extrusion die.

[0025] 2. The synergistic effect of the components in this invention reduces internal friction of the melt and forms a stable slip layer at the interface between the melt and the mold, significantly reducing extrusion pressure, eliminating flow marks and clouding, and giving the product excellent demolding smoothness and surface gloss.

[0026] 3. By introducing a neutral stabilizer with a specific structure into the modified siloxane graft, the side reaction active sites during the modification process are passivated. It also produces a strong synergistic effect with the anti-dripping thermal stabilizer, effectively inhibiting the thermal degradation and hydrolysis of PC under high temperature and high shear, and preventing material discoloration and decline in mechanical properties.

[0027] 4. The microscopic combination of weather-resistant stabilizing components and modified siloxane grafts constructs a multidimensional photoprotection network in the polycarbonate matrix, enhancing the shielding and absorption efficiency of ultraviolet rays, effectively inhibiting yellowing and embrittlement caused by photo-oxidative degradation, and significantly improving the service life of polycarbonate hollow boards in harsh outdoor environments.

[0028] 5. The combination of the dispersed phase and the modified siloxane graft ensures the microscopic uniform dispersion of each functional additive in the high-viscosity polycarbonate matrix, avoids material defects caused by additive agglomeration, and guarantees the uniformity of the physical properties of the hollow board. Attached Figure Description

[0029] Figure 1 The infrared spectrum of the modified siloxane graft prepared in Example 2 of this invention is shown. Detailed Implementation

[0030] 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.

[0031] Preparation Example 1: Preparation of neutral stabilizers: ; Under nitrogen protection, 5 g of 3,5-di-tert-butyl-4-hydroxybenzyl alcohol and 90 ml of anhydrous dichloromethane were added to a round-bottom flask and stirred until uniformly dispersed. 4.12 g of CDI was dissolved in the remaining 60 ml of anhydrous DCM to prepare a solution, which was then slowly added dropwise to the reaction flask. After the addition was complete, the reaction mixture was stirred at room temperature for 2 hours. After the reaction was complete, the reaction solution was directly transferred to a separatory funnel. The organic phase was washed twice with 100 ml of water and then rapidly washed with 100 ml of saturated saline solution. The organic phase was dried over anhydrous sodium sulfate for 30 minutes. The drying agent was removed by filtration, and the filtrate was concentrated by rotary evaporation under reduced pressure to obtain the crude product. The crude product was purified by rapid column chromatography. The stationary phase was silica gel; the mobile phase was a gradient-eluted mixture of petroleum ether and ethyl acetate, with a volume ratio gradually changing from 10:1 to 4:1. The fraction containing the target product was collected, concentrated under reduced pressure, and dried under vacuum to give 6.07 g of solid product 3,5-di-tert-butyl-4-hydroxybenzyl 1H-imidazolium-1-carboxylic acid ester.

[0032] Mass spectrometry (MS+H) of 3,5-di-tert-butyl-4-hydroxybenzyl 1H-imidazol-1-carboxylic acid ester + :331.

[0033] ; Under nitrogen protection, 6.07 g of 3,5-di-tert-butyl-4-hydroxybenzyl 1H-imidazol-1-carboxylic acid ester, 2.83 g of (7-oxabicyclo[4.1.0]heptane-3-yl)methanol, and 50 mL of dichloromethane were added to a round-bottom flask and stirred until uniformly dispersed. Then, 2.75 g of DBU was added dropwise over 5 minutes with stirring, and the syringe and flask walls were rinsed with 10 mL of solution. The reaction was carried out at room temperature for 6 hours with stirring. After the reaction was complete, the reaction solution was transferred to a separatory funnel. The organic phase was washed once with 30 mL of 1 mol / L HCl aqueous solution, followed by washing once with 30 mL of saturated sodium bicarbonate aqueous solution and 30 mL of saturated brine. The organic layer was dried over anhydrous sodium sulfate for 30 minutes and filtered to remove the drying agent. The filtrate was evaporated under reduced pressure to remove the solvent, yielding the crude product. The crude product was purified by rapid column chromatography with silica gel as the stationary phase and a gradient-eluted mixture of petroleum ether and ethyl acetate in a volume ratio gradually changing from 10:1 to 5:1 as the mobile phase. The fraction containing the target product was collected, concentrated under reduced pressure, and dried under vacuum to obtain 5.76 g of (7-oxabicyclo[4.1.0]heptane-3-yl)methyl(3,5-di-tert-butyl-4-hydroxybenzyl) carbonate, which is a neutral stabilizer.

[0034] Mass spectrometry (MS+H) of (7-oxabicyclo[4.1.0]heptane-3-yl)methyl(3,5-di-tert-butyl-4-hydroxybenzyl) carbonate + 391; NMR of (7-oxabicyclo[4.1.0]heptane-3-yl)methyl(3,5-di-tert-butyl-4-hydroxybenzyl) carbonate - CDCl3: δ 7.18 (s, 2H), 5.23 (s, 1H), 5.08 (s, 2H), 4.05–3.98 (m, 2H), 3.19–3.12 (m, 2H), 1.95–1.80 (m, 2H), 1.70–1.48 (m, 3H), 1.44 (s, 18H), 1.35–1.10 (m, 2H).

[0035] Preparation Example 2: Preparation of modified siloxane graft A1: (1) Raw materials and proportions: Weigh the following raw materials by weight: a) 45 parts of dimethylsiloxane (reactive terminal siloxane) with glycidyl ether esters; b) 30 parts of KF-393 (siloxane grafting precursor); c) Diluent: 18 parts of dioctyl sebacate; d) Catalyst: 0.15 parts of dibutyltin dilaurate; e) Inhibitor: 0.10 parts of calcium stearate (calcium stearate); f) Prepare 0.40 parts of the neutral stabilizer obtained in Example 1.

[0036] (2) Reaction steps: Under inert gas (nitrogen) protection, a), b), and c) were added to a reaction vessel, heated to 105°C, and stirred at 400 rpm for 30 min to ensure homogeneity. Then d) and e) were added, and the temperature was raised to 110°C and held constant for 2 h for coupling grafting reaction. After the reaction, the temperature was lowered to below 80°C, f) (a neutral stabilizer) was added, and stirring continued for 40 min to capture residual active groups, suppress subsequent side reactions, and stabilize the system. After cooling to room temperature, the mixture was filtered through a 200-mesh filter to obtain modified siloxane graft A1. The infrared spectrum of modified siloxane graft A1 is shown below. Figure 1 .

[0037] Preparation Example 3: Preparation of modified siloxane graft A2: (1) Raw materials and proportions: Weigh the following raw materials by weight: a) 38 parts of single-terminated aminopropyl polydimethylsiloxane (reactive end-group siloxane); b) 40 parts of KF-859 (siloxane grafting precursor); c) Diluent: 12 parts of diisodecyl adipate; d) Catalyst: 0.10 parts of stannous octoate; e) Inhibitor: 0.08 parts of epoxidized soybean oil; f) Prepare 0.30 parts of the neutral stabilizer obtained in Example 1.

[0038] (2) Reaction steps: Under inert gas (argon) protection, a), b), and c) were added to a reaction vessel, heated to 95°C, and stirred at 350 rpm for 40 min to ensure homogeneity. Then d) and e) were added, and the temperature was raised to 105°C and maintained at this temperature for a coupling grafting reaction for 2.5 h. After the reaction was complete, the temperature was lowered to below 80°C, f) (a neutral stabilizer) was added, and stirring continued for 35 min to capture residual active groups, suppress subsequent side reactions, and stabilize the system. After cooling to room temperature, the mixture was filtered through a 200-mesh filter to obtain modified siloxane graft A2.

[0039] Preparation Example 4: Preparation of modified siloxane graft A3: (1) Raw materials and proportions: Weigh the following raw materials by weight: a) 52 parts of dual-terminated aminopropyl polydimethylsiloxane (reactive terminal siloxane); b) 25 parts of KF-393 (siloxane grafting precursor); c) Diluent: 22 parts polyethylene glycol dimethyl ether; d) Catalyst: 0.20 parts triethylamine; e) Inhibitor: 0.15 parts of triphenyl phosphite; f) Prepare 0.60 parts of the neutral stabilizer obtained in Example 1.

[0040] (2) Reaction steps: Under inert gas (nitrogen) protection, a), b), and c) were added to a reaction vessel, heated to 115°C, and stirred at 450 rpm for 25 min to ensure homogeneity. Then d) and e) were added, the temperature was adjusted to 112°C, and the coupling grafting reaction was carried out at this temperature for 1.5 h. After the reaction was completed, the temperature was lowered to below 80°C, f) (a neutral stabilizer) was added, and stirring continued for 45 min to capture residual active groups, suppress subsequent side reactions, and stabilize the system. After cooling to room temperature, the mixture was filtered through a 200-mesh filter to obtain modified siloxane graft A3.

[0041] Comparative preparation example 1: The preparation was carried out according to the same raw material ratio and reaction steps as in Preparation Example 2, except that the neutral stabilizer added in Preparation Example 2 was replaced with calcium stearate, while all other conditions remained unchanged; the inhibitor calcium stearate in the reaction control system remained unchanged at 0.10 parts, that is, the total amount of calcium stearate added in the system was 0.50 parts. After the reaction was completed, it was also filtered through a 200-mesh filter to obtain modified siloxane graft B1.

[0042] Comparative preparation example 2: The modified siloxane graft B2 was prepared by referring to the preparation method of Preparation Example 2, except that the neutral stabilizer was replaced with epoxidized soybean oil, and the rest remained the same as in Preparation Example 2.

[0043] Comparative preparation example 3: The modified siloxane graft B3 was prepared according to the preparation method of Preparation Example 2, except that the neutral stabilizer was not added, and the rest remained the same as in Preparation Example 2.

[0044] Comparative preparation example 4: The modified siloxane graft compound B4 was prepared by referring to the preparation method of Preparation Example 2, except that the siloxane graft precursor was not added, and the rest remained the same as in Preparation Example 2.

[0045] Example 1: Preparation of a processing lubricant composition for high weather-resistant polycarbonate hollow sheets: 1. Raw material components by weight: Weather-resistant internal lubricant: 30 parts pentaerythritol stearate; Weather-resistant external lubricant: 18 parts of oxidized polyethylene wax; Low-migration slippery component: 5 parts polytetrafluoroethylene micro powder; Anti-dripping heat stabilizer synergist: 1.0 part of a composition of hindered phenolic antioxidant 1010 and phosphite antioxidant 168 (mass ratio 1:1); Weather-stabilizing component: UV absorber UV-3263 parts; Modified siloxane grafts: 15 parts of the modified siloxane grafts A1 obtained in Preparation Example 2; Dispersed phase: 38 parts of polycarbonate powder.

[0046] 2. Preparation method: Premixing: According to the above-mentioned mass proportions, the weather-resistant internal lubricant, weather-resistant external lubricant, low-migration slip component, anti-drip heat stabilizer synergist, weather-resistant stabilizing component, modified siloxane graft A1, and polycarbonate powder are added together into a high-pressure mixer. The mixing conditions are set as follows: temperature 50℃, rotation speed 1000 rpm, and mixing time 15 minutes. After thorough mixing, a uniform premix is ​​obtained. Melt extrusion: The premixed material is added to a twin-screw extruder for melt granulation. The temperatures of each zone of the twin-screw extruder are set as follows: Zone 1 190℃, Zone 2 220℃, Zone 3 240℃, Zone 4 250℃, Zone 5 250℃, and the die head temperature is 240℃; the screw speed is controlled at 300 rpm. After melting, shearing, and mixing, the material is extruded. Cooling and pelletizing: After the extrudate is cooled to room temperature in a water cooling tank, it is cut into uniform pellets by a pelletizer. The pellets are then placed in a drying oven at 80-100℃ and dried at 90℃ for 4 hours to remove moisture and residual volatiles, thus obtaining the processing lubricant composition for high weather-resistant polycarbonate hollow boards.

[0047] Example 2: The preparation of a processing lubricant composition for high weather-resistant polycarbonate hollow boards is carried out by referring to the preparation method of Example 1, except that the modified siloxane graft A1 is replaced with modified siloxane graft A2, and the rest is the same as in Example 1.

[0048] Example 3: The preparation of a processing lubricant composition for high weather-resistant polycarbonate hollow boards is carried out by referring to the preparation method of Example 1, except that the modified siloxane graft A1 is replaced with modified siloxane graft A3, and the rest is the same as in Example 1.

[0049] Comparative Example 1: The preparation of a processing lubricant composition for high weather-resistant polycarbonate hollow boards is carried out by referring to the preparation method of Example 1, except that the modified siloxane graft A1 is replaced with modified siloxane graft B1, and the rest is the same as in Example 1.

[0050] Comparative Example 2: The preparation of a processing lubricant composition for high weather-resistant polycarbonate hollow boards is carried out by referring to the preparation method of Example 1, except that the modified siloxane graft A1 is replaced with modified siloxane graft B2, and the rest is the same as in Example 1.

[0051] Comparative Example 3: The preparation of a processing lubricant composition for high weather-resistant polycarbonate hollow boards is carried out by referring to the preparation method of Example 1, except that the modified siloxane graft A1 is replaced with modified siloxane graft B3, and the rest is the same as in Example 1.

[0052] Comparative Example 4: The preparation of a processing lubricant composition for high weather-resistant polycarbonate hollow boards is carried out by referring to the preparation method of Example 1, except that the modified siloxane graft A1 is replaced with modified siloxane graft B4, and the rest is the same as in Example 1.

[0053] Comparative Example 5: The preparation of a processing lubricant composition for high weather-resistant polycarbonate hollow panels is carried out by referring to the preparation method of Example 1, except that the modified siloxane graft A1 is replaced with bi-terminated glycidyl ether polydimethylsiloxane, and the rest is the same as in Example 1.

[0054] Comparative Example 6: The preparation of a processing lubricant composition for high weather-resistant polycarbonate hollow boards is carried out by referring to the preparation method of Example 1, except that the modified siloxane graft A1 is replaced with a mixture of di-terminated glycidyl ether polydimethylsiloxane and KF-393 in a mass ratio of 2:1, and the rest is the same as in Example 1.

[0055] Performance testing: 1. Sample Preparation: The PC resin and lubricant composition was put into a high-pressure mixer, the temperature was set at 50℃ and the speed at 1000 r / min, and the mixture was mixed for 15 min to obtain a uniform premix. The premix was then added to a twin-screw extruder, and the temperatures of each zone of the extruder were set as follows: Zone 1 190℃, Zone 2 220℃, Zone 3 240℃, Zone 4 250℃, Zone 5 250℃, and the die head temperature 240℃. The screw speed was 300 r / min. After melt extrusion, the mixture was water-cooled and pelletized, and then dried (90℃ / 4h) to obtain modified PC granules. The modified PC granules were injection molded into impact test strips (GB / T1843-2008 simple supported beam without notch) and tensile test strips (GB / T1040-2006 Type I). Hollow board samples: Hollow board samples of 100mm×100mm×4mm (uniform wall thickness, no obvious bubbles or cracks) were extruded through a hollow board extruder.

[0056] 2. Demolding force test: Fix the standard injection molded sample (100mm×10mm×4mm) inside the mold, and pull the sample out of the mold at a uniform speed using a tensile testing machine. Record the maximum tensile force as the demolding force. The data is shown in Table 1.

[0057] 3. Surface smoothness test: Refer to the test method of GB / T1031-2009 "Surface roughness parameters and their values ​​of plastics", randomly select 5 test points on the surface of the strip or hollow board sample (avoiding the edges) and test the Ra value. The data are shown in Table 1.

[0058] 4. Surface haze degree (haze change): Refer to the test method of GB / T2410-2008 "Determination of light transmittance and haze of transparent plastics"; test the initial haze (H0) of the hollow board sample; place the sample in a constant temperature and humidity chamber, set the temperature to 80℃ and the humidity to 50%RH, and age for 1000h; after cooling to room temperature, test the haze (H1) after aging, and calculate the haze increment ΔH=H1-H0. The data are shown in Table 1.

[0059] 5. Yellowing Index (YI) Test: Refer to the test method of GB / T2409-1980 "Test Method for Yellowing Index of Plastics"; test the initial yellowing index (YI0) of the test specimen; age for 2000h under the UV aging conditions of transmittance retention test; test the yellowing index (YI1) after aging, and calculate the yellowing index increment ΔYI=YI1-YI0. The data are shown in Table 1.

[0060] Table 1 Examples 1-3 exhibited the smallest haze increments. The modified siloxane grafts contain PC-compatible segments. During processing, these segments bond in situ with the PC chains, locking the lubricant components within the matrix and fundamentally solving the haze problem caused by the migration and release of small molecules. In contrast, the comparative examples lacked effective grafting structures or eliminated physical mixing, making the lubricant prone to migrating to the surface during high-temperature aging, resulting in a significant increase in ΔH.

[0061] Internal lubricant (forming pentaerythritol stearate) reduces intermolecular friction, while external lubricant creates a slip layer. Physical mixing (Comparative Example 6), although having a lubricating effect, suffers from poor compatibility, leading to localized concentrated or uneven surface distribution, resulting in a high Ra value and poor release force due to the lack of uniform molecular-level distribution.

[0062] The prepared neutral stabilizer combines a hindered phenolic antioxidant structure with ethylene oxide functionality. Comparative Examples 1-3 induced an acute or decreased reaction in PC at high temperatures, resulting in significant yellowing of the stabilizer, with Comparative Example 3 showing the most severe yellowing, demonstrating the crucial role of this specific structure in inhibiting photo-oxidation and thermal degradation.

[0063] 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 processing lubricant composition for high weather-resistant polycarbonate hollow sheets, characterized in that, Its raw materials include the following components in parts by weight: 20-45 parts of weather-resistant internal lubricant; 10-25 parts of weather-resistant external lubricant; 2-10 parts of low-migration slippery component; Anti-drip heat stabilizer 0.3-2.0 parts; 0.5-6 parts of weather-stabilizing component; 8-25 parts of modified siloxane graft; Dispersed phase 20-55 parts; The modified siloxane graft compound is prepared from the following raw materials in parts by weight: 35-55 parts of reactive terminal siloxane, 20-45 parts of siloxane grafting precursor, 0.05-0.50 parts of reaction control system, 0.10-0.80 parts of neutral stabilizer, and 10-25 parts of diluent. The neutral stabilizer is .

2. The processing lubricant composition for high weather-resistant polycarbonate hollow boards according to claim 1, characterized in that, The weather-resistant internal lubricant is selected from at least one of pentaerythritol stearate, glyceryl monostearate, stearamide stearate, and stearamide. The weather-resistant external lubricant is selected from at least one of the following: polyethylene wax, oxidized polyethylene wax, montan wax, stearic acid, and calcium stearate; The low-migration slippery component is selected from at least one of the following: polytetrafluoroethylene micro powder, polyvinylidene fluoride powder, and perfluoropolyether.

3. The processing lubricant composition for high weather-resistant polycarbonate hollow boards according to claim 1, characterized in that, The anti-drip heat stabilizer synergist is selected from at least two of the following: hindered phenolic antioxidant 1010, hindered phenolic antioxidant 1076, phosphite antioxidant 168, and phosphite antioxidant 626, with a mass ratio of 1:

1. The weather-resistant stabilizing component is selected from at least one of the following: UV absorber UV-326, UV absorber UV-329, UV absorber UV-531, hindered amine light stabilizer 770, and hindered amine light stabilizer 622. The dispersed phase is selected from at least one of the following: polycarbonate powder, polycarbonate and polyethylene terephthalate copolyester, and polycarbonate and polyethylene terephthalate copolyester.

4. The processing lubricant composition for high weather-resistant polycarbonate hollow boards according to claim 1, characterized in that, The reactive terminal siloxane is selected from at least one of the following: single-terminated glycidyl ether polydimethylsiloxane, double-terminated glycidyl ether polydimethylsiloxane, single-terminated aminopropyl polydimethylsiloxane, and double-terminated aminopropyl polydimethylsiloxane. The siloxane grafting precursor is selected from either KF-393 or KF-859.

5. The processing lubricant composition for high weather-resistant polycarbonate hollow boards according to claim 1, characterized in that, The reaction regulation system includes a catalyst and an inhibitor; The catalyst is selected from at least one of the following: dibutyltin dilaurate, stannous octoate, triethylamine, and triethylenediamine; The inhibitor is selected from at least one of calcium stearate, epoxidized soybean oil, and triphenyl phosphite.

6. The processing lubricant composition for high weather-resistant polycarbonate hollow boards according to claim 1, characterized in that, The diluent is selected from at least one of the following: dioctyl sebacate, diisodecyl adipate, polyethylene glycol dimethyl ether, and polypropylene glycol dimethyl ether.

7. A method for preparing a processing lubricant composition for high weather-resistant polycarbonate hollow sheets as described in any one of claims 1 to 6, characterized in that, Includes the following steps: 1) Premixing: According to the mass ratio, the weather-resistant internal lubricant, weather-resistant external lubricant, low-migration slip component, anti-drip heat stabilizer synergist, weather-resistant stabilizing component, modified siloxane graft and dispersed phase are put into a high-pressure mixer for mixing to obtain a premix; 2) Melt extrusion: The premixed material is added to a twin-screw extruder for melt granulation; 3) Cooling and pelletizing: After the extrudate is cooled in a water cooling tank, it is pelletized by a pelletizer and dried to obtain the processing lubricant composition for high weather-resistant polycarbonate hollow boards.

8. The method for preparing the processing lubricant composition for high weather-resistant polycarbonate hollow sheets according to claim 7, characterized in that, The mixing conditions described in step 1) are: temperature 40 to 60°C, rotation speed 800 to 1200 revolutions per minute, and mixing time 10 to 20 minutes.

9. The method for preparing the processing lubricant composition for high weather-resistant polycarbonate hollow sheets according to claim 7, characterized in that, The temperature settings for each zone of the twin-screw extruder described in step 2) are as follows: Zone 1 180 to 200℃, Zone 2 210 to 230℃, Zone 3 230 to 250℃, Zone 4 240 to 260℃, Zone 5 240 to 260℃, and the die head temperature 230 to 250℃; the screw speed is controlled at 200 to 400 revolutions per minute.

10. The method for preparing the processing lubricant composition for high weather-resistant polycarbonate hollow sheets according to claim 7, characterized in that, The drying conditions described in step 3) are: drying at 80 to 100°C for 3 to 5 hours.

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