A polycarbonate-based light-guiding composition, and a method of preparing and using the same

Abstract

The present application relates to the technical field of polycarbonate light guide products, and specifically discloses a polycarbonate-based light guide composition, a preparation method and application thereof.The polycarbonate-based light guide composition comprises the following raw materials: linear polycarbonate, an antioxidant with a specific structure, a lubricant and a stabilizer; the content of small molecules (referring to a molecular weight of ≤4000 Da) of the linear polycarbonate is ≤4.5 wt%.The present application controls the content of small molecules of the linear polycarbonate, realizes long-term and stable light transmittance of the polycarbonate-based light guide composition, and through the addition of a small amount of the antioxidant with the specific structure and the synergistic effect of other additives, significantly reduces the yellowing index of the light guide composition, so that the polycarbonate-based light guide composition has excellent yellowing resistance, and meanwhile effectively avoids the loss of the linear polycarbonate in mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of polycarbonate light guide products, and in particular to a polycarbonate-based light guide composition, its preparation method, and its application. Background Technology

[0002] Polycarbonate is a colorless and transparent engineering plastic with advantages such as good toughness, ease of processing, and impact resistance, and is widely used in light guides, lenses, optical instruments, and automotive light strips. However, when used in optical devices, the light transmittance of polycarbonate, one of the indicators of transparency, is lower than that of polymethyl methacrylate (PMMA). Therefore, when using polycarbonate as a light guide or display panel light source, problems such as low light brightness and yellowing occur. How to prepare polycarbonate light guide products with better optical properties has become a research hotspot.

[0003] Currently, the main approaches to improving the optical performance of polycarbonate light guides are: reducing the content of chromophores (such as potassium and sodium ions), adding a second polymer (such as polyalkylene glycols, polyalkylene glycol fatty acid esters, polyether polyols, or polyester polyol auxiliaries), and adding antioxidants (such as phosphite antioxidants). However, although existing polycarbonate light guides possess a certain degree of resistance to yellowing, they still cannot meet the current requirements for light transmittance and yellowing resistance in the field, given the trends towards thinner, lighter, more labor-saving, and more precise optical devices. Furthermore, existing polycarbonate light guides have low impact strength and are not durable enough for practical use. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a polycarbonate-based light guide composition, its preparation method, and its application. By improving the purity of polycarbonate, introducing antioxidants with specific structures, and combining them with lubricants and stabilizers, the polycarbonate-based light guide composition retains excellent light transmittance and yellowness index even after processing at high temperatures, and also exhibits good mechanical properties.

[0005] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows: In a first aspect, the present invention provides a polycarbonate-based light guide composition comprising the following raw materials: linear polycarbonate, antioxidant, lubricant, and stabilizer; The linear polycarbonate has a small molecule content ≤ 4.5 wt%; the antioxidant has the structural formula shown in Formula I:

[0006] Formula I.

[0007] Compared to existing technologies, the polycarbonate-based light guide composition provided by this invention significantly improves the optical performance of the polycarbonate-based light guide composition by limiting the content of small molecules (molecular weight ≤ 4000 Da) of linear polycarbonate. The use of antioxidants with specific structures significantly improves the light transmittance of the polycarbonate-based light guide composition, reduces the yellowness index, and enhances thermal stability. After using the antioxidants provided by this invention, the polycarbonate-based light guide composition still exhibits excellent optical performance and resistance to yellowing after heat retention injection molding.

[0008] Preferably, the polycarbonate-based light guide composition comprises the following raw materials in parts by weight: 100 parts linear polycarbonate, 0.01 to 0.1 parts antioxidant, 0.1 to 0.5 parts lubricant, and 0.1 to 1 parts stabilizer.

[0009] More preferably, the polycarbonate-based light guide composition comprises the following raw materials in parts by weight: 100 parts linear polycarbonate, 0.02 to 0.07 parts antioxidant, 0.15 to 0.4 parts lubricant, and 0.2 to 0.6 parts stabilizer.

[0010] More preferably, the polycarbonate-based light guide composition comprises the following raw materials in parts by weight: 100 parts linear polycarbonate, 0.03 to 0.06 parts antioxidant, 0.2 to 0.4 parts lubricant, and 0.2 to 0.5 parts stabilizer.

[0011] This invention, by limiting the raw materials and their proportions, achieves both synergistic effects and effective cost control. Experiments show that as the antioxidant content increases, the light transmittance of the polycarbonate-based light guide composition increases, while the yellowness index decreases.

[0012] Preferably, the linear polycarbonate has a small molecule content ≤4.01wt%, a weight-average molecular weight (Mw) ≥20500Da, and a polymer dispersibility index (PDI) ≤1.68.

[0013] More preferably, the linear polycarbonate has a small molecule content ≤3.5wt%, a weight-average molecular weight of 20550Da~20800Da, and a polymer dispersibility index of 1.62~1.66.

[0014] Preferably, the linear polycarbonate is a bisphenol A type aromatic polycarbonate.

[0015] Preferably, under test conditions of 300°C and 1.2kg load, the melt index of the linear polycarbonate is 5g / 10min to 65g / 10min.

[0016] More preferably, under test conditions of 300°C and 1.2kg load, the melt index of the linear polycarbonate is 10g / 10min to 55g / 10min, more preferably 20g / 10min to 40g / 10min, and even more preferably 30g / 10min to 35g / 10min.

[0017] Preferably, the method for preparing the linear polycarbonate includes the following steps: Step 1: Add high-purity bisphenol A to sodium hydroxide solution to obtain bisphenol A sodium salt solution; Phosgene is added to dichloromethane to obtain a phosgene solution; Step 2: Add the sodium bisphenol A solution and the phosgene solution to a tubular reactor for the first reaction; add a capping agent for the second reaction; adjust the pH of the reaction system to 10.5-11.5 for the third reaction; add dichloromethane and the first catalyst for the fourth reaction to obtain the linear polycarbonate.

[0018] This invention provides a method for preparing linear polycarbonate. A sodium bisphenol A solution is used as the aqueous phase, and a phosgene solution as the oil phase. A tubular reactor is employed to mix the aqueous and oil phases, and linear polycarbonate is obtained through polymerization under the action of a capping agent and a first catalyst. The raw material, bisphenol A, has high purity and low levels of impurities such as phenol, 2,4-isomers, and triphenols, ensuring a low content of small molecules in the linear polycarbonate. This guarantees that the polycarbonate-based light guide composition obtained from the linear polycarbonate has long-lasting and stable light transmittance. This invention uses an insulated tubular reactor, making the polymerization method simple and rapid, significantly shortening the polymerization time. Simultaneously, the obtained linear polycarbonate has a high heat resistance rating, and the low content of small molecules in the polymer system allows for effective control of the molecular weight and structure of the polycarbonate.

[0019] More preferably, in step 1, the purity of the high-purity bisphenol A is ≥99.9wt%, and the residual amount of phenol is ≤0.01wt%.

[0020] More preferably, the purity of the recrystallized bisphenol A is ≥99.95wt%, and the residual amount of phenol is ≤0.001wt%.

[0021] More preferably, in step 1, the high-purity bisphenol A is obtained by recrystallization of bisphenol A from toluene.

[0022] More preferably, the mass-to-volume ratio of bisphenol A and toluene is (40~80) g:(150~200) mL.

[0023] More preferably, the recrystallization temperature is 110°C to 120°C.

[0024] For example, in step 1, the mass concentration of the sodium hydroxide solution is 5wt%~8wt%.

[0025] More preferably, in step 1, the molar ratio of high-purity bisphenol A to sodium hydroxide in the bisphenol A sodium salt solution is 1:(2~2.1).

[0026] More preferably, in step 1, the phosgene concentration in the phosgene solution is 13wt%~16wt%.

[0027] More preferably, in step 1, the molar ratio of phosgene to high-purity bisphenol A is (1.1~1.3):1.

[0028] More preferably, in step 2, the capping agent is an 8wt%~12wt% p-tert-butylphenol solution.

[0029] More preferably, in step 2, the first catalyst is a 5wt%~8wt% triethylamine solution.

[0030] More preferably, in step 2, the time for the first reaction is 5 min to 6 min.

[0031] More preferably, the molar ratio of p-tert-butylphenol (PTBP) in the capping agent to bisphenol A sodium salt (BPA-Na) in the bisphenol A sodium salt solution is (5~5.5):100.

[0032] More preferably, in step 2, the reaction time of the second reaction is 5.5 min to 6.5 min.

[0033] More preferably, in step 2, the time for the third reaction is 4 min to 5 min.

[0034] More preferably, in step 2, the concentration of the reaction system after adding the dichloromethane is 12wt%~15wt%.

[0035] More preferably, in step 2, the amount of triethylamine (TEA) in the first catalyst is 900 ppm to 1100 ppm of the mass of the reaction system.

[0036] More preferably, in step 2, the time for the fourth reaction is 3 min to 4 min.

[0037] Preferably, the method for preparing the antioxidant includes the following steps: Under an inert atmosphere, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl ester and a second catalyst were added to a solvent, phosphorus trichloride was added, and a fifth reaction was carried out at 45℃~55℃. A sixth reaction was carried out at 110℃~130℃ to obtain the antioxidant.

[0038] The above reaction equation is shown in Equation II:

[0039] Formula II.

[0040] More preferably, the second catalyst comprises pyromellitic trimethylamide and pyridine in a molar ratio of (0.9~1.1):1.

[0041] More preferably, the solvent includes xylene.

[0042] More preferably, the molar ratio of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl ester, the second catalyst, the solvent, and phosphorus trichloride is (4.5~5.5):(4.5~5.5):(18~22):1.

[0043] More preferably, the time for the fifth reaction is 5h to 7h.

[0044] More preferably, the time for the sixth reaction is 7h to 9h.

[0045] For example, after the sixth reaction, the process also includes: removing the solvent by vacuum distillation, followed by silica gel column chromatography (eluent is dichloromethane and methanol in a volume ratio of (40~80):1) to obtain the antioxidant.

[0046] Preferably, the lubricant includes at least one of the following: fatty alcohol lubricants, metal soap lubricants, fatty acid lubricants, fatty acid ester lubricants, lignite acid, lignite acid derivative lubricants, amide wax lubricants, saturated hydrocarbon lubricants, polyolefin wax, polyolefin wax derivative lubricants, organosilicon lubricants, silicone powder lubricants, or organofluorine lubricants.

[0047] More preferably, the lubricant is at least one of fatty acid ester lubricants.

[0048] More preferably, the fatty acid ester lubricant includes at least one of pentaerythritol tetrastearate (PETS), triglycerides, butyl stearate, or dioctyl adipate.

[0049] More preferably, the fatty alcohol lubricant includes at least one of octanol, decanol, dodecanol, tetradecyl alcohol, octadecyl alcohol, or eicosyl alcohol.

[0050] More preferably, the metal soap lubricant includes at least one of calcium stearate, calcium palmitate, zinc stearate, or zinc palmitate.

[0051] More preferably, the fatty acid lubricant includes at least one of stearic acid, palmitic acid, oleic acid, linoleic acid, or lauric acid.

[0052] More preferably, the linalool derivative lubricant includes at least one of linalool glycosamide or linalool glyceryl ester.

[0053] More preferably, the amide wax lubricant includes at least one of hydroxymethylstearamide or fatty acid diacetamide.

[0054] More preferably, the saturated hydrocarbon lubricant includes at least one of n-octacosane, isohexadecane, and decahydronaphthalene.

[0055] More preferably, the polyolefin wax derivative lubricant includes at least one of maleic anhydride-grafted polyethylene wax, acrylic acid-grafted polypropylene wax, polyethylene wax carboxylic ester, or polyethylene wax amide.

[0056] More preferably, the silicone lubricant includes at least one of phenyl silicone oil or amino silicone oil.

[0057] More preferably, the organofluorine lubricant includes at least one of perfluoropolyether or polychlorotrifluoroethylene.

[0058] Preferably, the stabilizer includes phosphorous acid, epoxy resin, and polytetrahydrofuran.

[0059] More preferably, the epoxy resin includes at least one of bisphenol A type epoxy resin, bisphenol F type epoxy resin, or hydrogenated bisphenol A type epoxy resin.

[0060] More preferably, the epoxy resin is a bisphenol A type epoxy resin.

[0061] More preferably, the mass ratio of phosphorous acid, epoxy resin and polytetrahydrofuran is 2:(2.5~3.5):(4~6).

[0062] By specifying the specific types of lubricants and stabilizers, this invention can further ensure that linear polycarbonate is easy to demold during extrusion injection molding and reduce molecular hydrolysis.

[0063] Secondly, the present invention provides a method for preparing the polycarbonate-based light guide composition, comprising the following steps: S100. Mix linear polycarbonate, antioxidant, lubricant and stabilizer evenly to obtain a premix; S200. Using a twin-screw extruder, the premixed material is melted, extruded, filtered, and pelletized to obtain a polycarbonate-based light guide composition.

[0064] The method for preparing the polycarbonate-based light guide composition provided by the present invention involves adding premixed material to a twin-screw extruder using a loss-in-weight feeder and a starvation feeding method. The temperature of the processing zone is controlled, and the material is fully melted under the conveying and shearing action of the screw. The material is then extruded, filtered, and pelletized to obtain the polycarbonate-based light guide composition.

[0065] Preferably, in S200, the melting temperature is 200℃~285℃.

[0066] More preferably, in S200, the melting temperature is 220℃~280℃.

[0067] Preferably, in S200, the main motor speed of the twin-screw extruder is 150 rpm to 500 rpm.

[0068] Preferably, in S200, a melt filter is connected to the rear end of the extrusion device of the twin-screw extruder, and the sieve size of the melt filter is 200 mesh to 300 mesh.

[0069] This invention improves the purity of the polycarbonate-based light guide composition by adding a melt filter at the rear end of the extrusion device, which is beneficial to improving optical performance.

[0070] Thirdly, the present invention provides a polycarbonate light guide article, comprising the aforementioned polycarbonate-based light guide composition.

[0071] Preferably, the polycarbonate light guide product includes at least one of automotive lamp light guides, automotive light strips, or automotive interior products.

[0072] The present invention has the following beneficial effects: This invention achieves long-lasting and stable light transmittance of polycarbonate-based light guide compositions by controlling the purity of bisphenol A, the raw material for the synthesis of linear polycarbonate. By adding a small amount of antioxidant with a specific structure, which works synergistically with other additives, the yellowing index of the light guide composition is significantly reduced, giving the polycarbonate-based light guide composition excellent yellowing resistance, while effectively avoiding the loss of mechanical properties of linear polycarbonate.

[0073] Regarding the preparation method of linear polycarbonate, this invention further reduces the content of cyclic oligomers by controlling the concentration and amount of each material; by using a tubular reactor, the polymerization reaction is simpler and faster, resulting in linear polycarbonate with higher heat resistance and mechanical strength, and better control over the molecular weight and structure of polycarbonate. Detailed Implementation

[0074] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0075] In the embodiments and comparative examples of this invention, all products are commercially available. Bisphenol A type epoxy resin was purchased from Maclean Company, model E-51; bisphenol F type epoxy resin was purchased from Maclean Company, model E-44; and hydrogenated bisphenol A type epoxy resin was purchased from Maclean Company, model E-45.

[0076] Example 1 This embodiment provides a linear polycarbonate (denoted as PC-1), the preparation method of which includes the following steps: Step 1: Add 50g of bisphenol A to 200mL of toluene and recrystallize at 120℃ until completely dissolved (approximately 5-8 minutes). Cool to room temperature to obtain high-purity bisphenol A (purity 99.9wt%, phenol residue 7ppm). Add the high-purity bisphenol A to a 6wt% sodium hydroxide solution to obtain a sodium bisphenol A solution (molar ratio of high-purity bisphenol A to sodium hydroxide 1:2.05).

[0077] Phosgene was added to dichloromethane to obtain a 14.5 wt% phosgene solution.

[0078] Step 2: Add bisphenol A sodium salt solution and phosgene solution to a tubular reactor (molar ratio of phosgene to high-purity bisphenol A is 1.18:1) for the first reaction. After 5 min 40 s, add 10 wt% PTBP solution (molar ratio of PTBP to BPA-Na is 5.2:100) for the second reaction. After 5 min 55 s, adjust the pH of the reaction system to 11 for the third reaction. After 4 min 35 s, add dichloromethane to dilute to 15 wt% (concentration of the reaction system), then add 6 wt% triethylamine solution (the amount of TEA is 1000 ppm of the reaction system mass) for the fourth reaction. After 3 min 20 s, separate the solid and liquid phases to obtain linear polycarbonate PC-1.

[0079] PC-1 was acid-washed and washed with water until the conductivity of the aqueous phase was below 10 μS / cm. The contents of bisphenol A in the aqueous phase and chloroformate in the oil phase were tested. The molecular weight, PDI, and small molecule content of PC-1 (the portion with a molecular weight less than 4000 Da was considered the small molecule content) were measured using a GPC gel chromatograph (Shimadzu RESERVOIR TRAY). The mobile phase was tetrahydrofuran, the flow rate was 1 mL / min, polystyrene was used as a standard, the column temperature was 40℃, and the test time was 30 min. The test results are shown in Table 1.

[0080] Example 2 This embodiment provides a linear polycarbonate (denoted as PC-2), the preparation method of which includes the following steps: Step 1: Add 80g of bisphenol A to 150mL of toluene and recrystallize at 110℃ until completely dissolved. Cool to room temperature to obtain high-purity bisphenol A (purity 98.7wt%, phenol residue 32ppm). Add the high-purity bisphenol A to a 7wt% sodium hydroxide solution to obtain a sodium bisphenol A solution (molar ratio of high-purity bisphenol A to sodium hydroxide 1:2.1).

[0081] Phosgene was added to dichloromethane to obtain a 15 wt% phosgene solution.

[0082] Step 2: Add bisphenol A sodium salt solution and phosgene solution to a tubular reactor (molar ratio of phosgene to high-purity bisphenol A is 1.25:1) for the first reaction. After 5 min 20 s, add 12 wt% PTBP solution (molar ratio of PTBP to BPA-Na is 5.4:100) for the second reaction. After 6 min, adjust the pH of the reaction system to 11 for the third reaction. After 4 min 30 s, add dichloromethane to dilute to 14 wt%, then add 7 wt% triethylamine solution (the amount of TEA is 1050 ppm of the reaction system mass) for the fourth reaction. After 3 min 40 s, separate the solid and liquid phases to obtain linear polycarbonate PC-2.

[0083] PC-2 was acid-washed and water-washed until the conductivity of the aqueous phase was below 10 μS / cm. The contents of bisphenol A in the aqueous phase and chloroformate in the oil phase were tested. The molecular weight, PDI and small molecule content of PC-2 were measured using GPC gel chromatography (test conditions were the same as in Example 1). The test results are shown in Table 1.

[0084] Comparative Example 1 This comparative example provides a linear polycarbonate (denoted as PC-3), the preparation method of which includes the following steps: Step 1: Add bisphenol A (purity of 98.0 wt%, phenol residue of 48 ppm) to a 5 wt% sodium hydroxide solution to obtain a bisphenol A sodium salt solution (molar ratio of bisphenol A to sodium hydroxide is 1:2).

[0085] Phosgene was added to dichloromethane to obtain a 14 wt% phosgene solution.

[0086] Step 2: Add bisphenol A sodium salt solution and phosgene solution to a tubular reactor (molar ratio of phosgene to high-purity bisphenol A is 1.13:1) to carry out the first reaction. After 5 min 30 s, add 8 wt% PTBP solution (molar ratio of PTBP to BPA-Na is 5.1:100) to carry out the second reaction. After 6 min, adjust the pH of the reaction system to 11 to carry out the third reaction. After 4 min 30 s, add dichloromethane to dilute to 14 wt%, and then add 5 wt% triethylamine solution (the amount of TEA is 950 ppm of the reaction system mass) to carry out the fourth reaction. After 3 min 30 s, separate the solid and liquid to obtain linear polycarbonate PC-3.

[0087] PC-3 was acid-washed and water-washed until the conductivity of the aqueous phase was below 10 μS / cm. The contents of bisphenol A in the aqueous phase and chloroformate in the oil phase were tested. The molecular weight, PDI and small molecule content of PC-3 were measured using GPC gel chromatography (test conditions were the same as in Example 1). The test results are shown in Table 1.

[0088] Table 1. Chemical residues and molecular weight results for PC-1 to PC-3

[0089] As can be seen from Table 1, with the increase of bisphenol A purity, the content of small molecules in the synthesized linear polycarbonate sample decreased significantly, from 4.65% to 3.29%.

[0090] Example 3 This embodiment provides an antioxidant as shown in Formula I, the preparation method of which includes the following steps: Under an inert atmosphere, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl ester and a second catalyst (trimethylammonium pyridine in a molar ratio of 1:1) were added to xylene and mixed thoroughly. Phosphorus trichloride (the molar ratio of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl ester, the second catalyst, xylene, and phosphorus trichloride was 5:5:20:1) was added dropwise at 50°C. After reacting at this temperature for 6 hours, the temperature was raised to 120°C and the reaction was continued for 8 hours. The solvent was removed by vacuum distillation, and the antioxidant was obtained by silica gel column chromatography with a yield of 85.2%.

[0091] 1H NMR spectrum: 1 H NMR (400 MHz, CDCl3, 298 K, δ in ppm): 6.89 (6H, s), 4.21(6H, t), 2.90 (6H, t), 2.54 (6H, t), 1.62 (6H, m), 1.42 (60H, m), 1.28 (84H,m), 0.86 (9H, t).

[0092] Carbon NMR spectrum: 13 C NMR (100 MHz, CDCl3, 298 K, δ in ppm): 171.5, 146.8,143.5, 130.9, 124.0, 66.1, 35.8, 34.6, 31.4, 29.2, 26.0, 22.8, 14.3.

[0093] High-resolution mass spectrometry: HRMS (ESI, m / z ): [M +H] + calc. for C 105 H 184 O9P + , 1620.3678;found, 1620.3672.

[0094] Elemental analysis: EA : [C 105 H 183 O9P] calc. for C, 77.82%; H, 11.38%; O, 8.89%; P, 1.91%; found, C, 77.78%; H, 11.42%; O, 8.91%; P, 1.89%.

[0095] Example 4 This embodiment provides an antioxidant as shown in Formula I, the preparation method of which includes the following steps: Under an inert atmosphere, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl ester and a second catalyst (trimethylammonium pyromellitic acid and pyridine in a molar ratio of 1.1:1) were added to xylene and mixed thoroughly. Phosphorus trichloride (the molar ratio of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl ester, the second catalyst, xylene, and phosphorus trichloride was 4.5:4.5:18:1) was added dropwise at 55°C. After reacting at this temperature for 5.5 h, the temperature was raised to 115°C and the reaction was continued for another 8.5 h. The solvent was removed by vacuum distillation, and the antioxidant was obtained by silica gel column chromatography with a yield of 85.0%.

[0096] Example 5 This embodiment provides a polycarbonate-based light guide composition comprising the following raw materials in parts by weight: 100 parts of linear polycarbonate (PC-1) from Example 1, 0.02 parts of antioxidant from Example 3, 0.15 parts of lubricant (PETS), and 0.2 parts of stabilizer. The stabilizer is composed of phosphorous acid, bisphenol A type epoxy resin, and polytetrahydrofuran in a mass ratio of 2:2.5:4.

[0097] The preparation method of the above-mentioned polycarbonate-based light guide composition includes the following steps: S100. Add linear polycarbonate, antioxidant, lubricant and stabilizer to a high-speed mixer and mix for 5 minutes to obtain a premix.

[0098] S200. The premixed material is added to a twin-screw extruder. The processing temperature is controlled at 200℃~275℃ and the main machine speed is 200rpm. A melt filter with a sieve size of 300 mesh is connected to the rear end of the extrusion device of the twin-screw extruder. The premixed material is melted, extruded, filtered, and pelletized. Then it is dried at 70℃ for 4h to obtain a polycarbonate-based light guide composition.

[0099] Example 6 This embodiment provides a polycarbonate-based light guide composition comprising the following raw materials in parts by weight: 100 parts of linear polycarbonate (PC-1) from Example 1, 0.04 parts of antioxidant from Example 3, 0.3 parts of lubricant (tetradecyl alcohol), and 0.4 parts of stabilizer. The stabilizer is composed of phosphorous acid, bisphenol A type epoxy resin, and polytetrahydrofuran in a mass ratio of 2:3.5:6.

[0100] The preparation method of the above-mentioned polycarbonate-based light guide composition includes the following steps: S100. Add linear polycarbonate, antioxidant, lubricant and stabilizer to a high-speed mixer and mix for 7 minutes to obtain a premix.

[0101] S200. The premixed material is added to a twin-screw extruder, and the processing temperature is controlled at 210℃~275℃ and the main machine speed is 300rpm. A melt filter with a screen size of 300 mesh is connected to the rear end of the extrusion device of the twin-screw extruder to melt, extrude, filter, and pelletize the premixed material. Then it is dried at 80℃ for 3.5h to obtain a polycarbonate-based light guide composition.

[0102] Example 7 This embodiment provides a polycarbonate-based light guide composition comprising the following raw materials in parts by weight: 100 parts of linear polycarbonate (PC-1) from Example 1, 0.07 parts of antioxidant from Example 3, 0.4 parts of lubricant (calcium palmitate), and 0.6 parts of stabilizer. The stabilizer is composed of phosphorous acid, bisphenol A type epoxy resin, and polytetrahydrofuran in a mass ratio of 2:3:5.

[0103] The preparation method of the above-mentioned polycarbonate-based light guide composition includes the following steps: S100. Add linear polycarbonate, antioxidant, lubricant and stabilizer to a high-speed mixer and mix for 8 minutes to obtain a premix.

[0104] S200. The premixed material is added to a twin-screw extruder, and the processing temperature is controlled at 200℃~280℃ and the main machine speed is 400rpm. A melt filter with a screen size of 300 mesh is connected to the rear end of the extrusion device of the twin-screw extruder to melt, extrude, filter, and pelletize the premixed material. Then it is dried at 90℃ for 3~4h to obtain a polycarbonate-based light guide composition.

[0105] Example 8 This embodiment provides a polycarbonate-based light guide composition comprising the following raw materials in parts by weight: 100 parts of linear polycarbonate (PC-2) from Example 2, 0.05 parts of antioxidant from Example 3, 0.2 parts of lubricant (PETS), and 0.3 parts of stabilizer. The stabilizer is composed of phosphorous acid, bisphenol F epoxy resin, and polytetrahydrofuran in a mass ratio of 2:3:5.

[0106] The preparation method of the above-mentioned polycarbonate-based light guide composition includes the following steps: S100. Add linear polycarbonate, antioxidant, lubricant and stabilizer to a high-speed mixer and mix for 10 minutes to obtain a premix.

[0107] S200. The premixed material is added to a twin-screw extruder, and the processing temperature is controlled at 220℃~285℃ and the main machine speed is 500rpm. A melt filter with a 200-mesh sieve is connected to the rear end of the extrusion device of the twin-screw extruder to melt, extrude, filter, and pelletize the premixed material. Then it is dried at 100℃ for 3 hours to obtain a polycarbonate-based light guide composition.

[0108] Example 9 This embodiment provides a polycarbonate-based light guide composition comprising the following raw materials in parts by weight: 100 parts of linear polycarbonate (PC-1) from Example 1, 0.05 parts of antioxidant from Example 4, 0.35 parts of lubricant (linalool ethylenediamide), and 0.5 parts of stabilizer. The stabilizer is composed of phosphorous acid, hydrogenated bisphenol A epoxy resin, and polytetrahydrofuran in a mass ratio of 2:3:5.

[0109] The preparation method of the above polycarbonate-based light guide composition is the same as that in Example 7, and will not be repeated here.

[0110] Comparative Example 2 This comparative example provides a polycarbonate-based light guide composition, the raw material composition and ratio of which are similar to those of Example 6, except that PC-1 is replaced with an equal mass of PC-3 from Comparative Example 1. All other conditions are the same as in Example 6 and will not be repeated here.

[0111] The preparation method of the above polycarbonate-based light guide composition is the same as that in Example 6, and will not be repeated here.

[0112] Comparative Example 3 This comparative example provides a polycarbonate-based light guide composition, the raw material composition and ratio of which are similar to those of Example 6, except that the antioxidant of Example 3 is omitted. All other conditions are the same as in Example 6 and will not be repeated.

[0113] The preparation method of the above polycarbonate-based light guide composition is the same as that in Example 6, and will not be repeated here.

[0114] Comparative Example 4 This comparative example provides a polycarbonate-based light guide composition, whose raw material composition and ratio are similar to those of Example 7, except that the antioxidant in Example 3 is replaced with equal masses of antioxidant 1076 and antioxidant 626, with a mass ratio of antioxidant 1076 to antioxidant 626 of 1:4. All other conditions are the same as in Example 7 and will not be repeated here.

[0115] The preparation method of the above polycarbonate-based light guide composition is the same as that in Example 7, and will not be repeated here.

[0116] Comparative Example 5 This comparative example provides a polycarbonate-based light guide composition, the raw material composition and ratio of which are similar to those of Example 7, except that the antioxidant in Example 3 is replaced with an equal mass of antioxidant B900. All other conditions are the same as in Example 7 and will not be repeated.

[0117] The preparation method of the above polycarbonate-based light guide composition is the same as that in Example 7, and will not be repeated here.

[0118] Comparative Example 6 This comparative example provides a polycarbonate-based light guide composition, the raw material composition and ratio of which are similar to those of Example 7, except that the antioxidant in Example 3 is replaced with an equal mass of antioxidant 1076. All other conditions are the same as in Example 7 and will not be repeated.

[0119] The preparation method of the above polycarbonate-based light guide composition is the same as that in Example 7, and will not be repeated here.

[0120] Comparative Example 7 This comparative example provides a polycarbonate-based light guide composition, whose raw material composition and ratio are similar to those of Example 9, except that the stabilizer is omitted. All other conditions are the same as in Example 9 and will not be repeated.

[0121] The preparation method of the above polycarbonate-based light guide composition is the same as that in Example 7, and will not be repeated here.

[0122] Comparative Example 8 This comparative example provides a method for preparing a polycarbonate-based light guide composition, the steps of which are similar to those in Example 7, except that: the extrusion unit of the twin-screw extruder is not connected to a melt filter at the rear end, and the extruded material is directly pelletized without filtration. All other conditions are the same as in Example 7 and will not be repeated.

[0123] The raw material composition and ratio of the above polycarbonate-based light guide composition are the same as those in Example 7, and will not be repeated here.

[0124] Application examples This application example provides an automotive light guide component. The polycarbonate-based light guide compositions of Examples 5-9 and Comparative Examples 2-8 are injection molded into structural components with an oblong top view, measuring 200 mm in length, 30 mm in width, and 11 mm in height. Each polycarbonate-based light guide composition is placed in an injection molding machine with a mold temperature of 60°C-90°C, a barrel temperature of 250°C-280°C, an injection speed of 30 mm / s-100 mm / s, and an injection pressure of 30 bar-100 bar.

[0125] Verification test 1. The melt index, transmittance, haze, yellow index and notched impact strength of the polycarbonate-based light guide compositions of Examples 5-9 and Comparative Examples 2-8 were tested according to the reference standards ISO1133, ISO 13468, ISO 14782, ASTM E313 transmission method and ISO 180 respectively. The test results are shown in Tables 2 and 3.

[0126] Table 2 Performance test results of the polycarbonate-based light guide compositions of the examples and comparative examples 1

[0127] Table 3 Performance test results of the polycarbonate-based light guide compositions of the examples and comparative examples 2

[0128] As can be seen from Tables 2 and 3: (1) Compared with antioxidant B900, antioxidant 1076 and antioxidant 626 compound and antioxidant 1076, the polycarbonate-based light guide composition has good light transmittance and yellowness index after using the antioxidant shown in Formula I, and its thermal stability is better.

[0129] (2) As the antioxidant content increases, the light transmittance of the polycarbonate-based light guide composition increases, while the yellowing index decreases.

[0130] (3) By strictly controlling the content of phenol in the linear polycarbonate synthesis raw materials, polycarbonate with a light transmittance of more than 90% and a yellowness index of ≤0.9 can be obtained, and the mechanical properties of the polycarbonate-based light guide composition are not lost.

[0131] (4) The addition of stabilizers improves the processing stability of linear polycarbonate, stabilizes the melt index, and makes linear polycarbonate molecules less prone to degradation.

[0132] (5) Increasing the area of ​​the filter at the back end of the extrusion to improve the purity of the sample is beneficial to the optical performance of the polycarbonate-based light guide composition. As the purity of bisphenol A increases, the optical performance of the polycarbonate-based light guide composition also increases.

[0133] 2. The performance parameters (transmittance, haze, yellow index and notched impact strength) of the polycarbonate-based light guide compositions of Examples 5-9 and Comparative Examples 2-8 after high-temperature heat retention were tested according to the reference standards ISO 13468, ISO 14782, ASTM E313 transmission method and ISO 180 respectively. The test results are shown in Tables 4 and 5.

[0134] Table 4 Performance test results of various polycarbonate-based light guide compositions at 320℃ (0 min)

[0135] Table 5. Performance test results of various polycarbonate-based light guide compositions after 30 minutes at 320℃.

[0136] 3. The transmittance, haze, and yellow index of each automotive light guide component in the corresponding test cases were tested according to the reference standards ISO 13468, ISO 14782, ASTM E313 transmission method and ISO 180 respectively. The test results are shown in Table 6.

[0137] Table 6 shows the performance test results of various automotive light guide components in the application examples.

[0138] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A polycarbonate-based light guide composition, characterized in that, It includes the following raw materials: linear polycarbonate, antioxidants, lubricants, and stabilizers; The linear polycarbonate has a small molecule content ≤ 4.5 wt%; the antioxidant has the structural formula shown in Formula I: Formula I.

2. The polycarbonate-based light guide composition according to claim 1, characterized in that, The polycarbonate-based light guide composition comprises the following raw materials in parts by weight: 100 parts linear polycarbonate, 0.01 to 0.1 parts antioxidant, 0.1 to 0.5 parts lubricant, and 0.1 to 1 parts stabilizer.

3. The polycarbonate-based light guide composition as described in claim 1, characterized in that, The linear polycarbonate has a small molecule content ≤4.01wt%, a weight-average molecular weight ≥20500Da, and a polymer dispersibility index ≤1.68; The linear polycarbonate is a bisphenol A type aromatic polycarbonate; Under test conditions of 300℃ and 1.2kg load, the melt index of the linear polycarbonate is 5g / 10min to 65g / 10min.

4. The polycarbonate-based light guide composition according to any one of claims 1 to 3, characterized in that, The method for preparing the linear polycarbonate includes the following steps: Step 1: Add high-purity bisphenol A to sodium hydroxide solution to obtain bisphenol A sodium salt solution; Phosgene is added to dichloromethane to obtain a phosgene solution; Step 2: Add the sodium bisphenol A solution and the phosgene solution to a tubular reactor for the first reaction; add a capping agent for the second reaction; adjust the pH of the reaction system to 10.5-11.5 for the third reaction; add dichloromethane and the first catalyst for the fourth reaction to obtain the linear polycarbonate.

5. The polycarbonate-based light guide composition according to claim 4, characterized in that, In step 1, the high-purity bisphenol A is obtained by recrystallization of bisphenol A from toluene; the purity of the high-purity bisphenol A is ≥99.9 wt%, and the residual amount of phenol is ≤0.01 wt%. In step 1, the molar ratio of high-purity bisphenol A to sodium hydroxide in the bisphenol A sodium salt solution is 1:(2~2.1), the mass concentration of phosgene in the phosgene solution is 13wt%~16wt%, and the molar ratio of phosgene to high-purity bisphenol A is (1.1~1.3):1; In step 2, the capping agent is an 8wt%~12wt% p-tert-butylphenol solution, and the first catalyst is a 5wt%~8wt% triethylamine solution; The molar ratio of p-tert-butylphenol in the capping agent to sodium bisphenol A in the sodium bisphenol A solution is (5~5.5):100; in step 2, the concentration of the reaction system after adding dichloromethane is 12wt%~15wt%, and the amount of triethylamine in the first catalyst is 900ppm~1100ppm of the mass of the reaction system. In step 2, the first reaction takes 5 to 6 minutes, the second reaction takes 5.5 to 6.5 minutes, the third reaction takes 4 to 5 minutes, and the fourth reaction takes 3 to 4 minutes.

6. The polycarbonate-based light guide composition according to claim 1, characterized in that, The method for preparing the antioxidant includes the following steps: Under an inert atmosphere, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl ester and a second catalyst were added to a solvent, phosphorus trichloride was added, and a fifth reaction was carried out at 45℃~55℃. A sixth reaction was carried out at 110℃~130℃ to obtain the antioxidant.

7. The polycarbonate-based light guide composition according to claim 6, characterized in that, The second catalyst comprises pyromellitic trimethylamide and pyridine in a molar ratio of (0.9~1.1):1, and the solvent comprises xylene; The molar ratio of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl ester, the second catalyst, the solvent, and phosphorus trichloride is (4.5~5.5):(4.5~5.5):(18~22):1; The fifth reaction takes 5 to 7 hours, and the sixth reaction takes 7 to 9 hours.

8. The polycarbonate-based light guide composition according to claim 1, characterized in that, The lubricant includes at least one of the following: fatty alcohol lubricants, metal soap lubricants, fatty acid lubricants, fatty acid ester lubricants, lignite acid, amide wax lubricants, saturated hydrocarbon lubricants, polyolefin waxes, organosilicon lubricants, silicone powder lubricants, or organofluorine lubricants. The stabilizer comprises phosphorous acid, epoxy resin, and polytetrahydrofuran in a mass ratio of 2:(2.5~3.5):(4~6).

9. A method for preparing the polycarbonate-based light guide composition according to any one of claims 1 to 8, characterized in that, Includes the following steps: S100. The linear polycarbonate, antioxidant, lubricant and stabilizer are mixed evenly to obtain a premix. S200. Using a twin-screw extruder, the premixed material is melted, extruded, filtered, and pelletized to obtain a polycarbonate-based light guide composition.

10. A polycarbonate light guide product, characterized in that, The polycarbonate-based light guide composition includes the polycarbonate-based light guide composition according to any one of claims 1 to 8 or the polycarbonate-based light guide composition prepared by the method of preparing the polycarbonate-based light guide composition according to claim 9.

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