Stabilizer composition and preparation method thereof, purification method of polycarbonate solution and preparation method of polycarbonate

Abstract

The invention relates to the field of chemical engineering, in particular to a stabilizer composition and a preparation method thereof, a purification method of a polycarbonate solution and a preparation method of polycarbonate. The stabilizer composition provided by the invention is formed by matching a multifunctional hindered phenol antioxidant, a high-temperature-discoloration-resistant hindered phenol antioxidant, a phenol-free high-phosphorus liquid spiro phosphite antioxidant, a carbon free radical scavenger, an inorganic acid absorbent and polycarbonate powder according to a certain proportion, the antioxidant is 2, 5-di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine, and the hindered phenol antioxidant resistant to high temperature discoloration is triethylene glycol bis [3-(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate]. The stabilizer composition provided by the invention can provide protection for polycarbonate in high-temperature treatment (solvent removal, extrusion, injection molding processing and the like) processes, and the yellowing resistance of polycarbonate in the high-temperature process is improved.

Description

Technical Field

[0001] This invention relates to the chemical industry, and in particular to a stabilizer composition and its preparation method, a method for purifying polycarbonate solutions, and a method for preparing polycarbonate. Background Technology

[0002] Aromatic polycarbonate (mainly bisphenol A type polycarbonate) is an engineering plastic with excellent comprehensive properties, including superior transparency, impact resistance, heat resistance, and dimensional stability. It is widely used in electronic and electrical equipment, building materials, optical media, packaging, the automotive industry, lenses, and medical devices. Currently, there are two main production processes for aromatic polycarbonate: phosgenation interfacial polycondensation and melt transesterification polycondensation. In the phosgenation interfacial polycondensation process, the polycarbonate solution obtained after polycondensation, separation, washing, and filtration is then desorbed to remove the organic solvent dichloromethane, yielding solid polycarbonate, which is then dried before being extruded.

[0003] For solvent removal processes, current industrial production often employs steam removal and heating evaporation. When using steam, the steam is hot and humid, typically above 200°C, with some areas reaching 300°C. Heating evaporation typically involves heating to 250-350°C. Both of these conditions easily cause polycarbonate degradation and yellowing. Some industrial solvent removal devices use long vaporization pipes (e.g., serpentine pipes), where the solvent is carried away by steam, allowing liquid polycarbonate to advance and eventually solidify. Prolonged exposure to the high temperature and humidity of these pipes can also damage polycarbonate and cause yellowing. Residual dichloromethane (tens to hundreds of ppm) in the polycarbonate system readily reacts with residual moisture to form hydrochloric acid. Residual sodium chloride reacts with residual or degraded bisphenol A to form hydrochloric acid, and chloride ions from residual sodium chloride also accelerate polycarbonate degradation and yellowing during solvent removal and subsequent processing, especially under high-temperature conditions. In addition, residual metallic impurities such as molybdenum, vanadium, zirconium, titanium, iron, chromium, and niobium from raw materials and equipment during the production process can also lead to a decrease in the color stability of polycarbonate and an increase in the yellow index.

[0004] All of the above adverse factors can damage polycarbonate, including yellowing, molecular chain breakage, cross-linking leading to gelation, and decreased transparency. Adding antioxidants can reduce the degree of yellowing of polycarbonate, such as antioxidants 1076, 1010, 168, 626, 9228, PEP-36, 1500, and DHOP (PDP). However, many defects still exist in practical applications. For example, 1076 easily turns green at high temperatures and has low antioxidant efficiency; 1010 easily turns yellow-orange at high temperatures, and its branched structure makes it easy to precipitate during solvent removal and subsequent processing of polycarbonate; 168 easily turns yellow at high temperatures, and has low phosphorus content and low antioxidant efficiency; 626 is easily hydrolyzed to form yellow viscous lumps, and easily turns yellow-red at high temperatures; PEP-36 has a large degree of yellow-red change at high temperatures; 168, 626, 9228, and PEP-36 are easy to precipitate onto the surface of polycarbonate products to form bloom, affecting light transmittance and surface smoothness, and can also precipitate onto the internal surface of equipment to form deposits, leading to black spots and other problems; 1500 contains bisphenol A and phenol residues, which affect human health, and has low phosphorus content and low antioxidant efficiency; DHOP (PDP) has many benzene rings in its molecular structure, making it easy to precipitate, and also contains phenol residues, and the precipitate easily turns red-orange at high temperatures.

[0005] Therefore, how to protect polycarbonate during solvent removal and subsequent processing, reduce or delay the oxidative degradation of polycarbonate caused by high temperature, hydrochloric acid, chloride ions and metal impurities, thereby improving its yellowing resistance and reducing the degree of yellowing, has become an urgent problem to be solved. Summary of the Invention

[0006] In view of this, the present invention provides a stabilizer composition and its preparation method, a method for purifying polycarbonate solutions, and a method for preparing polycarbonate. The stabilizer composition provided by the present invention can protect polycarbonate during high-temperature treatment (solvent removal, extrusion, and injection molding, etc.) and improve the resistance of polycarbonate to yellowing during high-temperature processes.

[0007] This invention provides a stabilizer composition comprising, by weight percentage:

[0008] Multifunctional hindered phenolic antioxidant: 7.2%–9.3%;

[0009] High-temperature resistant color-discoloration hindered phenolic antioxidant: 1.8%–2.4%;

[0010] Phenol-free, high-phosphorus liquid spirocyclic phosphite antioxidant: 7.2%–9.3%;

[0011] Carbon free radical scavenger: 1.4%–2.4%;

[0012] Inorganic acid absorbent: 3.2%–3.9%;

[0013] Polycarbonate powder: Balance;

[0014] in,

[0015] The multifunctional hindered phenolic antioxidant is N,N′-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine;

[0016] The high-temperature resistant color-discoloration-hindering phenolic antioxidant is triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate].

[0017] Preferably, the phenol-free high-phosphorus liquid spirocyclic phosphite antioxidant is at least one of pentaerythritol diisodecyl diphosphite and pentaerythritol diisodecithyl diphosphite.

[0018] Preferably, the carbon radical scavenger is N,N-bis(C 16 -C 18 Alkyl) hydroxylamine, amine, bis(C) 14 -C 24 At least one of alkyl(methyl) or N-oxide.

[0019] Preferably, the inorganic acid absorbent is synthetic magnesium aluminum hydrotalcite.

[0020] Preferably, the synthetic magnesium aluminum hydrotalcite has the following specifications: MgO / Al2O3 molar ratio of 4 to 5; average particle size D50 of 0.3 to 0.6 μm; particle volume percentage of particles with a particle size ≤ 1 μm ≥ 85%; and particle volume percentage of particles with a particle size ≥ 5 μm ≥ 0%.

[0021] The present invention also provides a method for preparing the stabilizer composition described in the above technical solution, comprising: mixing a multifunctional hindered phenolic antioxidant, a high-temperature resistant color-changing hindered phenolic antioxidant, a phenol-free high-phosphorus liquid spirocyclic phosphite antioxidant, a carbon free radical scavenger, an inorganic acid scavenger, and polycarbonate powder to obtain the stabilizer composition.

[0022] Preferably, the mixing sequence is as follows: first, the polycarbonate powder and the solid additives among the above-mentioned additives are mixed to obtain a solid mixture; then, the liquid additives among the above-mentioned additives are sprayed into the solid mixture to obtain a stabilizer composition.

[0023] This invention also provides a method for purifying a polycarbonate solution, comprising:

[0024] (A) A polycarbonate solution is mixed with a stabilizer composition to obtain a mixture;

[0025] (B) Remove the solvent from the mixture obtained in step (A) to obtain polycarbonate;

[0026] The stabilizer composition is the stabilizer composition described in the above technical solution or is prepared by the preparation method described in the above technical solution.

[0027] Preferably, the amount of stabilizer composition added is 5500 to 6500 ppm, based on the polycarbonate in the polycarbonate solution.

[0028] The present invention also provides a method for preparing polycarbonate, comprising:

[0029] S1. Prepare a polycarbonate solution;

[0030] S2. The polycarbonate solution is purified to obtain polycarbonate;

[0031] The purification process employs the purification method described in the above technical solution.

[0032] The stabilizer composition provided by this invention is formed by combining a multifunctional hindered phenolic antioxidant, a high-temperature resistant color-changing hindered phenolic antioxidant, a phenol-free high-phosphorus liquid spirocyclic phosphite antioxidant, a carbon free radical scavenger, an inorganic acid scavenger, and polycarbonate powder in a certain proportion. The multifunctional hindered phenolic antioxidant is N,N′-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine, and the high-temperature resistant color-changing hindered phenolic antioxidant is triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate]. The combined action of these stabilizers, after application during the solvent removal process of polycarbonate solution, can solve the degradation and yellowing problem of polycarbonate caused by high temperature, hydrochloric acid, chloride ions, and metal impurities during high-temperature treatments such as solvent removal. The resulting polycarbonate has a low yellow index and excellent anti-yellowing performance. Furthermore, the stabilizer composition of this invention is a single-package additive, making it convenient to add. Detailed Implementation

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0034] In this article, the technical features described in an open-ended manner include both closed technical solutions composed of the listed features and open technical solutions that include the listed features.

[0035] The term “and / or” as used herein includes any and all combinations of one or more of the related listed items.

[0036] In this document, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when a range refers to an integer, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0037] In this article, when referring to units for data ranges, if the unit is only followed by the right endpoint, it indicates that the units for the left and right endpoints are the same. For example, 0.3–0.6 μm means that the units for the left endpoint “0.3” and the right endpoint “0.6” are both μm.

[0038] In a first aspect, the present invention provides a stabilizer composition comprising, by weight percentage:

[0039] Multifunctional hindered phenolic antioxidant: 7.2%–9.3%;

[0040] High-temperature resistant color-discoloration hindered phenolic antioxidant: 1.8%–2.4%;

[0041] Phenol-free, high-phosphorus liquid spirocyclic phosphite antioxidant: 7.2%–9.3%;

[0042] Carbon free radical scavenger: 1.4%–2.4%;

[0043] Inorganic acid absorbent: 3.2%–3.9%;

[0044] Polycarbonate powder: Balance;

[0045] in,

[0046] The multifunctional hindered phenolic antioxidant is N,N′-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine;

[0047] The high-temperature resistant color-discoloration-hindering phenolic antioxidant is triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate].

[0048] In this invention, the multifunctional hindered phenolic antioxidant is N,N′-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine (CAS No.: 32687-78-8), and its source is not particularly limited; it can be a commercially available product or prepared according to known methods in the art. The multifunctional hindered phenolic antioxidant used in this invention contains both an acylhydrazine structure and a hindered phenolic hydroxyl group. On the one hand, the acylhydrazine structure can bind to metal impurities to form a stable complex, preventing metal impurities from catalyzing the degradation of polycarbonate. On the other hand, the hindered phenolic hydroxyl group can capture alkoxy radicals and hydroxyl radicals generated during the high-temperature degradation of polycarbonate, terminating the free radical chain reaction and improving the thermal stability of polycarbonate. Through the combination of these two functional groups in a specific structure, yellowing of polycarbonate caused by metal impurities and high temperatures can be avoided. In this invention, the content of the multifunctional hindered phenolic antioxidant is 7.2% to 9.3%, specifically 7.2%, 7.3%, 7.4%, 7.5%, 7.6%, 7.7%, 7.8%, 7.9%, 8.0%, 8.1%, 8.2%, 8.3%, 8.4%, 8.5%, 8.6%, 8.7%, 8.8%, 8.9%, 9.0%, 9.1%, 9.2%, and 9.3%.

[0049] In this invention, the high-temperature color-changing hindered phenolic antioxidant is triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate] (CAS No.: 36443-68-2). This invention does not impose any special restrictions on the source of the high-temperature color-changing hindered phenolic antioxidant; it can be a commercially available product or prepared according to known methods in the art. In this invention, using a small amount of the above-mentioned high-temperature color-changing hindered phenolic antioxidant in combination with a multifunctional hindered phenolic antioxidant exhibits excellent synergistic effects, significantly improving the thermal stability and anti-yellowing properties of polycarbonate. Its structure contains asymmetric hindered phenolic hydroxyl groups, resulting in excellent anti-yellowing properties against light and smoke. In this invention, the content of the high-temperature color-changing hindered phenolic antioxidant is 1.8% to 2.4%, specifically 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, and 2.4%.

[0050] The multifunctional hindered phenolic antioxidant and the high-temperature color-changing hindered phenolic antioxidant used in this invention exhibit excellent color stability at high temperatures and better color protection for polycarbonate. For example, after being kept at 270°C for 10 minutes, the multifunctional hindered phenolic antioxidant is milky white and the high-temperature color-changing hindered phenolic antioxidant is colorless and transparent, with only slight color change at the edges. In contrast, other hindered phenolic antioxidants (such as 1076, 1010, 3114, 1098, 1330, 1790, AO-80, CPL, etc.) show obvious color changes (such as yellow, green, yellow-orange, yellow-brown, reddish-brown, etc.), affecting the application effect of the product.

[0051] In this invention, the phosphorus content of the phenol-free, high-phosphorus liquid spirocyclic phosphite antioxidant is >9.5%, preferably at least one of pentaerythritol diisodecyl diphosphite (CAS No.: 26544-27-4) and pentaerythritol diisodedecyl diphosphite (CAS No.: 69439-68-5), more preferably pentaerythritol diisodecyl diphosphite. This invention does not impose any particular limitation on the source of the phenol-free, high-phosphorus liquid spirocyclic phosphite antioxidant; it can be a commercially available product or prepared according to methods known in the art. The phenol-free, high-phosphorus liquid spirocyclic phosphite antioxidant used in this invention decomposes the hydroperoxides generated by the degradation of polycarbonate through the trivalent phosphorus structure, thereby improving the thermal stability and anti-yellowing performance of polycarbonate during high-temperature treatment (solvent removal, extrusion, and injection molding, etc.). Its advantages are: (1) It does not contain aromatic ring structures, and has no residues of phenol, nonylphenol, or bisphenol A, making it resistant to migration, safe, healthy, and environmentally friendly; (2) It has a high phosphorus content (>9.5%), strong ability to decompose hydroperoxides, and excellent antioxidant performance. High; (3) Contains a pentaerythritol-based spirocyclic structure, exhibits excellent thermal stability, and is resistant to yellowing at high temperatures. For example, after being kept at 260°C for 10 minutes, its appearance is colorless and transparent or white, while most phosphite antioxidants (168, 626, PEP-36, triisodecyl phosphite, triisodeciyl phosphite, 705T, DHOP, etc.) or their high-temperature precipitates show varying degrees of discoloration (e.g., light yellow, uneven light yellow, yellow, yellowish-red, deep yellowish-red, reddish-orange, etc.). Based on the above advantages, the phenol-free, high-phosphorus liquid spirocyclic phosphite antioxidant can effectively inhibit the yellowing of polycarbonate caused by high-temperature oxidation, providing polycarbonate with excellent thermal stability and color stability. In this invention, the content of the phenol-free, high-phosphorus liquid spirocyclic phosphite antioxidant is 7.2% to 9.3%, specifically 7.2%, 7.3%, 7.4%, 7.5%, 7.6%, 7.7%, 7.8%, 7.9%, 8.0%, 8.1%, 8.2%, 8.3%, 8.4%, 8.5%, 8.6%, 8.7%, 8.8%, 8.9%, 9.0%, 9.1%, 9.2%, and 9.3%.

[0052] In this invention, the carbon radical scavenger is a high-temperature resistant, color-changing carbon radical scavenger, preferably N,N-bis(C 16 -C 18 Alkyl) hydroxylamine, amine, bis(C) 14 -C 24 At least one of alkyl(methyl) and N-oxide, preferably N,N-bis(C) 16 -C 18 Alkyl)hydroxylamine. Wherein, the N,N-bis(C) 16 -C 18The alkyl hydroxylamine is specifically at least one of N,N-bis(hydrogenated tallow alkyl) hydroxylamine (CAS No.: 143925-92-2) and N,N-bis(hydrogenated palm oil alkyl) hydroxylamine (CAS No.: 1374859-51-4). The amine, bis(C 14 -C 24 The alkyl)methyl, N-oxide is preferably an amine, bis(hydrogenated rapeseed oil alkyl)methyl, N-oxide (CAS No.: 204933-93-7). This invention does not impose any particular restriction on the source of the carbon radical scavenger; it can be a commercially available product or prepared according to methods known in the art. The high-temperature resistant yellowing carbon free radical scavenger used in this invention can capture carbon free radicals generated by the high-temperature degradation of polycarbonate, terminate the carbon free radical chain reaction, and prevent carbon free radicals from continuing to react and generate alkoxy free radicals, hydroperoxides, etc. to the greatest extent. At the same time, it can protect the phenolic hydroxyl groups generated by the degradation of polycarbonate, the phenolic hydroxyl groups of residual bisphenol A, and the phenolic hydroxyl groups of hindered phenolic antioxidants from being oxidized into yellow quinone compounds, thereby reducing the degree of yellowing of polycarbonate. Its advantages are: (1) high carbon free radical scavenging efficiency; (2) excellent anti-yellowing performance at high temperature. For example, after being kept at 260°C for 10 minutes, it did not show obvious yellowing, while benzofuranone-type carbon free radical scavengers had turned yellow-green; (3) the molecular structure has no aromatic ring structure and contains long carbon chains, so it has good compatibility and is resistant to precipitation when added to the polycarbonate system. In this invention, the content of the carbon free radical scavenger is 1.4% to 2.4%, specifically 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, and 2.4%.

[0053] In this invention, the inorganic acid absorbent is preferably synthetic magnesium aluminum hydrotalcite (CAS No.: 11097-59-9). The preferred specifications of the synthetic magnesium aluminum hydrotalcite are: an MgO / Al2O3 molar ratio of 4–5; an average particle size D50 of 0.3–0.6 μm; a particle size ≤1 μm volume percentage ≥85%; and a particle size ≥5 μm volume percentage of 0%. Specifically, the molar ratio can be 4.0, 4.24, 4.27, 4.29, 4.3, or 5.0. The average particle size D50 can specifically be 0.37 μm, 0.39 μm, 0.42 μm, 0.47 μm, or 0.6 μm. Specifically, the particle size ≤1 μm volume percentage can be 85%, 90%, 91.7%, 95.4%, 97.7%, or 98.2%.

[0054] The present invention does not impose any special restrictions on the source of the inorganic acid absorbent; it may be a commercially available product or prepared according to known methods in the art. The acid absorber synthesized by this invention, magnesium aluminum hydrotalcite, can absorb hydrochloric acid and chloride ions generated by the reaction between residual or degradation products in the polycarbonate system, thus avoiding the accelerated degradation of polycarbonate by hydrochloric acid and chloride ions and the resulting discoloration and performance degradation. Its advantages are: (1) It does not migrate during the solvent removal and subsequent processing and application of polycarbonate, ensuring the acid absorption effect; (2) It has high acid absorption efficiency, about 2 to 3 times that of organic stearate acid absorbers, so the amount added is low; (3) After absorbing hydrochloric acid and chloride ions, through anion exchange, chloride ions and water can be intercalated and fixed inside, so that chloride ions do not precipitate out. At the same time, it does not produce acidic protons, easily migrating stearic acid, and easily absorbing water substances, thus avoiding affecting the color, surface smoothness, transparency and other properties of polycarbonate; (4) It has a small particle size and is evenly dispersed in polycarbonate, which does not affect the melt pressure of polycarbonate in the subsequent extrusion granulation process or the appearance and transparency of the product. In this invention, the content of the inorganic acid absorbent is 3.2% to 3.9%, specifically 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, and 3.9%.

[0055] In this invention, the polycarbonate powder is an aromatic polycarbonate powder, preferably with a weight-average molecular weight of 12,000 to 40,000, specifically 12,000, 15,000, 19,000, 20,000, 21,000, 24,700, 26,000, 27,000, 30,800, 31,000, 35,000, or 40,000. The source of the polycarbonate powder is not particularly limited; it can be prepared according to known polycarbonate polymerization processes in the art, such as phosgenation interfacial polycondensation. In this invention, the amount of polycarbonate powder used is a margin, i.e., to make up to 100%.

[0056] Secondly, the present invention also provides a method for preparing the stabilizer composition described in the above technical solution, comprising: mixing a multifunctional hindered phenolic antioxidant, a high-temperature resistant color-changing hindered phenolic antioxidant, a phenol-free high-phosphorus liquid spirocyclic phosphite antioxidant, a carbon free radical scavenger, an inorganic acid absorber, and polycarbonate powder to obtain the stabilizer composition.

[0057] The types and amounts of the multifunctional hindered phenolic antioxidant, high-temperature resistant color-changing hindered phenolic antioxidant, phenol-free high-phosphorus liquid spirocyclic phosphite antioxidant, carbon free radical scavenger, inorganic acid absorber, and polycarbonate powder are all consistent with those described in the previous technical solution, and will not be repeated here.

[0058] In this invention, the mixing method is preferably stirring. The preferred mixing sequence is: first, mixing the polycarbonate powder and the solid additives from the above-mentioned additives to obtain a solid mixture; then, mixing the solid mixture with the liquid additives from the above-mentioned additives to obtain a stabilizer composition. Preferably, the method of mixing the solid mixture with the liquid additives from the above-mentioned additives is to spray the liquid additives into the solid mixture. More specifically, the mixing process includes: adding the polycarbonate powder and the solid additives from the above-mentioned additives to a stirring device, stirring thoroughly to ensure uniform mixing of the materials, obtaining a solid mixture; then, under stirring conditions, spraying the liquid additives from the above-mentioned additives into the solid mixture to ensure thorough and uniform mixing of the solid mixture and the liquid stabilizer, thereby obtaining the stabilizer composition.

[0059] Thirdly, the present invention also provides a method for purifying a polycarbonate solution, comprising:

[0060] (A) A polycarbonate solution is mixed with a stabilizer composition to obtain a mixture;

[0061] (B) Remove the solvent from the mixture obtained in step (A) to obtain polycarbonate;

[0062] The stabilizer composition is the stabilizer composition described in the preceding technical solution.

[0063] Regarding step (A):

[0064] The polycarbonate solution refers to the crude polycarbonate solution formed during the polycarbonate production process. In this invention, the polycarbonate solution is an aromatic polycarbonate solution prepared by phosgenation interfacial polycondensation, specifically an aromatic polycarbonate dichloromethane solution prepared by phosgenation interfacial polycondensation. The concentration of the polycarbonate solution is preferably 15wt% to 30wt%, specifically 15wt%, 20wt%, 25wt%, or 30wt%. The weight-average molecular weight of the polycarbonate in the polycarbonate solution is preferably 12,000 to 40,000, specifically 12,000, 15,000, 19,000, 20,000, 21,000, 24,700, 26,000, 27,000, 30,800, 31,000, 35,000, or 40,000.

[0065] In this invention, based on the polycarbonate in the polycarbonate solution, the amount of the stabilizer composition added is preferably 5500-6500 ppm, that is, the amount of the stabilizer composition added is 5500-6500 ppm of the mass of the polycarbonate in the polycarbonate solution, specifically 5500 ppm, 5550 ppm, 5600 ppm, 5650 ppm, 5700 ppm, 5750 ppm, 5800 ppm, 5850 ppm, 5900 ppm, 5950 ppm, 6000 ppm, 6050 ppm, 6100 ppm, 6150 ppm, 6200 ppm, 6250 ppm, 6300 ppm, 6350 ppm, 6400 ppm, 6450 ppm, and 6500 ppm.

[0066] In existing technologies, the process for preparing polycarbonate involves first obtaining a polycarbonate solution and then removing the solvent. This invention adds a stabilizer composition to the polycarbonate solution before performing the solvent removal step. The stabilizer composition used in this invention protects the polycarbonate from yellowing during high-temperature treatments (solvent removal, and subsequent extrusion and injection molding processes), preventing degradation and yellowing caused by factors such as high temperature, hydrochloric acid, chloride ions, and metallic impurities.

[0067] Regarding step (B):

[0068] In this invention, the solvent removal method in step (B) is not particularly limited and can be any conventional method in the art; for example, solvent removal by steam or solvent evaporation by heating is preferred. In the steam solvent removal method, the steam temperature is generally 160–230°C. The specific process for steam solvent removal adopts methods known in the art, such as introducing or injecting high-temperature steam into a polycarbonate solution in a reactor, where the solvent dichloromethane evaporates and vaporizes under stirring conditions, resulting in solid polycarbonate in the reactor; or mixing the polycarbonate solution with steam and introducing it into an alloy condenser tube similar to a "serpentine tube," where the solvent dichloromethane evaporates and vaporizes during material movement, forming solid polycarbonate on the tube wall. When using solvent evaporation by heating, the polycarbonate solution is generally heated to 250–350°C in a multi-stage evaporator to evaporate the solvent dichloromethane, obtaining solid polycarbonate.

[0069] Fourthly, the present invention also provides a method for preparing polycarbonate, comprising: S1, preparing a polycarbonate solution; S2, purifying the polycarbonate solution to obtain polycarbonate. The purification is performed using the purification method described in the above-mentioned technical solution.

[0070] Regarding step S1:

[0071] The polycarbonate solution refers to the crude polycarbonate solution formed during the polycarbonate production process. This invention does not impose any special limitations on the preparation process of the polycarbonate solution; any preparation method known in the art can be followed. In this invention, the polycarbonate solution is an aromatic polycarbonate solution prepared by phosgenation interfacial polycondensation, specifically an aromatic polycarbonate dichloromethane solution prepared by phosgenation interfacial polycondensation. The concentration of the polycarbonate solution is preferably 15wt% to 30wt%, specifically 15wt%, 20wt%, 25wt%, or 30wt%. The weight-average molecular weight of the polycarbonate in the polycarbonate solution is preferably 12,000 to 40,000, specifically 12,000, 15,000, 19,000, 20,000, 21,000, 24,700, 26,000, 27,000, 30,800, 31,000, 35,000, or 40,000.

[0072] Regarding step S2:

[0073] In this invention, the purification method described in the preceding technical solution is used, as shown in steps (A) to (B) above, and will not be repeated here.

[0074] Fifthly, the present invention also provides a polycarbonate obtained by the purification method or preparation method described in the foregoing technical solutions.

[0075] Compared with the prior art, the present invention has the following beneficial effects:

[0076] (1) The stabilizer composition of the present invention is a packaged chemical additive, which is convenient to add and use. At the same time, when applied in polycarbonate, the stabilizer components are more evenly dispersed, which can improve the effect of use.

[0077] (2) The stabilizer composition of the present invention can protect polycarbonate from degradation and yellowing caused by high temperature, hydrochloric acid, chloride ions and metal impurities during high temperature treatment (solvent removal, extrusion and injection molding, etc.) through the synergistic effect of multiple stabilizers, thereby improving the anti-yellowing performance of polycarbonate.

[0078] (3) The stabilizer composition of the present invention protects polycarbonate from yellowing, and each component has excellent thermal stability and high temperature resistance to discoloration, thus avoiding adverse effects on polycarbonate and its products due to high temperature discoloration.

[0079] (4) The stabilizer composition of the present invention does not contain phenol, nonylphenol and bisphenol A residues, and is safe, healthy and environmentally friendly.

[0080] To further understand the present invention, preferred embodiments are described below with reference to examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims. Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0081] Example 1

[0082] 1. Stabilizer composition raw material formulation:

[0083] N,N′-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine: 7.2%;

[0084] Diethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate]: 1.8%;

[0085] Pentaerythritol diisodecyl diphosphite: 7.2%;

[0086] N,N-bis(hydrogenated tallow alkyl)hydroxylamine: 1.4%;

[0087] Synthetic magnesium aluminum hydrotalcite: 3.2%;

[0088] Polycarbonate powder: Balance;

[0089] in,

[0090] The specifications of the synthetic magnesium aluminum hydrotalcite are as follows: MgO / Al2O3 molar ratio is 4.27; average particle size D50 is 0.37μm; particle size ≤1μm accounts for 97.7% of the volume; and particle size ≥5μm accounts for 0% of the volume.

[0091] The polycarbonate powder is an aromatic polycarbonate powder with a weight-average molecular weight of 19,000.

[0092] 2. Preparation of stabilizer composition:

[0093] Polycarbonate powder and the solid additives from the above-mentioned additives are added to a stirring device and stirred thoroughly to make the materials evenly mixed to obtain a solid mixture. Then, under stirring conditions, the liquid additives from the above-mentioned additives are sprayed into the solid mixture to make the solid mixture and liquid stabilizer evenly mixed to obtain a stabilizer composition.

[0094] 3. Purification of polycarbonate solution:

[0095] (A) Add 5500 ppm of the above stabilizer composition to a polycarbonate dichloromethane solution (concentration of 20 wt%, weight average molecular weight of 26000) to obtain a mixture;

[0096] (B) High-temperature steam at 200°C is injected into the above mixture to remove dichloromethane, yielding solid polycarbonate.

[0097] Example 2

[0098] 1. Stabilizer composition raw material formulation:

[0099] N,N′-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine: 9.3%;

[0100] Triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate]: 2.4%;

[0101] Pentaerythritol diisodecyl diphosphite: 9.3%;

[0102] N,N-Bis(hydrogenated palm oil alkyl)hydroxylamine: 2.4%;

[0103] Synthetic magnesium aluminum hydrotalcite: 3.9%;

[0104] Polycarbonate powder: Balance;

[0105] in,

[0106] The specifications of the synthetic magnesium aluminum hydrotalcite are as follows: MgO / Al2O3 molar ratio is 4.27; average particle size D50 is 0.37μm; particle size ≤1μm accounts for 97.7% of the volume; and particle size ≥5μm accounts for 0% of the volume.

[0107] The polycarbonate powder is an aromatic polycarbonate powder with a weight-average molecular weight of 19,000.

[0108] 2. Preparation of stabilizer composition: Same as in Example 1.

[0109] 3. Purification of polycarbonate solution:

[0110] (A) Add 6500 ppm of the above stabilizer composition to a polycarbonate dichloromethane solution (concentration of 20 wt%, weight average molecular weight of 26000) to obtain a mixture;

[0111] (B) High-temperature steam at 200°C is injected into the above mixture to remove dichloromethane, yielding solid polycarbonate.

[0112] Example 3

[0113] 1. Stabilizer composition raw material formulation:

[0114] N,N′-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine: 8.3%;

[0115] Triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate]: 2.1%;

[0116] Pentaerythritol diisodecyl diphosphite: 8.3%;

[0117] N,N-Bis(hydrogenated palm oil alkyl)hydroxylamine: 1.9%;

[0118] Synthetic magnesium aluminum hydrotalcite: 3.6%;

[0119] Polycarbonate powder: Balance;

[0120] in,

[0121] The specifications of the synthetic magnesium aluminum hydrotalcite are as follows: MgO / Al2O3 molar ratio is 4.27; average particle size D50 is 0.37μm; particle size ≤1μm accounts for 97.7% of the volume; and particle size ≥5μm accounts for 0% of the volume.

[0122] The polycarbonate powder is an aromatic polycarbonate powder with a weight-average molecular weight of 21,000.

[0123] 2. Preparation of stabilizer composition: Same as in Example 1.

[0124] 3. Purification of polycarbonate solution:

[0125] (A) Add 6000 ppm of the above stabilizer composition to a polycarbonate dichloromethane solution (concentration of 20 wt%, weight average molecular weight of 26000) to obtain a mixture;

[0126] (B) High-temperature steam at 200°C is injected into the above mixture to remove dichloromethane, yielding solid polycarbonate.

[0127] Example 4

[0128] 1. Stabilizer composition raw material formulation:

[0129] N,N′-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine: 7.5%;

[0130] Triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate]: 2.2%;

[0131] Pentaerythritol diisodecyl diphosphite: 8.5%;

[0132] N,N-Bis(hydrogenated palm oil alkyl)hydroxylamine: 2.0%;

[0133] Synthetic magnesium aluminum hydrotalcite: 3.6%;

[0134] Polycarbonate powder: Balance;

[0135] in,

[0136] The specifications of the synthetic magnesium aluminum hydrotalcite are as follows: MgO / Al2O3 molar ratio is 4.29; average particle size D50 is 0.39μm; particle size ≤1μm accounts for 98.2% of the volume; and particle size ≥5μm accounts for 0% of the volume.

[0137] The polycarbonate powder is an aromatic polycarbonate powder with a weight-average molecular weight of 21,000.

[0138] 2. Preparation of stabilizer composition: Same as in Example 1.

[0139] 3. Purification of polycarbonate solution:

[0140] (A) Add 5800 ppm of the above stabilizer composition to a polycarbonate dichloromethane solution (concentration of 20 wt%, weight average molecular weight of 26000) to obtain a mixture;

[0141] (B) High-temperature steam at 200°C is injected into the above mixture to remove dichloromethane, yielding solid polycarbonate.

[0142] Example 5

[0143] 1. Stabilizer composition raw material formulation:

[0144] N,N′-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine: 9.0%;

[0145] Triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate]: 1.9%;

[0146] Pentaerythritol diisodecyl diphosphite: 7.8%;

[0147] N,N-bis(hydrogenated tallow alkyl)hydroxylamine: 1.6%;

[0148] Synthetic magnesium aluminum hydrotalcite: 3.3%;

[0149] Polycarbonate powder: Balance;

[0150] in,

[0151] The specifications of the synthetic magnesium aluminum hydrotalcite are as follows: MgO / Al2O3 molar ratio is 4.29; average particle size D50 is 0.39μm; particle size ≤1μm accounts for 98.2% of the volume; and particle size ≥5μm accounts for 0% of the volume.

[0152] The polycarbonate powder is an aromatic polycarbonate powder with a weight-average molecular weight of 24,700.

[0153] 2. Preparation of stabilizer composition: Same as in Example 1.

[0154] 3. Purification of polycarbonate solution:

[0155] (A) Add 6200 ppm of the above stabilizer composition to a polycarbonate dichloromethane solution (concentration of 20 wt%, weight average molecular weight of 26000) to obtain a mixture;

[0156] (B) High-temperature steam at 200°C is injected into the above mixture to remove dichloromethane, yielding solid polycarbonate.

[0157] Example 6

[0158] 1. Stabilizer composition raw material formulation:

[0159] N,N′-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine: 8.5%;

[0160] Triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate]: 2.3%;

[0161] Pentaerythritol diisotridecyl diphosphite: 9.1%;

[0162] N,N-bis(hydrogenated tallow alkyl)hydroxylamine: 2.2%;

[0163] Synthetic magnesium aluminum hydrotalcite: 3.8%;

[0164] Polycarbonate powder: Balance;

[0165] in,

[0166] The specifications of the synthetic magnesium aluminum hydrotalcite are as follows: MgO / Al2O3 molar ratio is 4.29; average particle size D50 is 0.39μm; particle size ≤1μm accounts for 98.2% of the volume; and particle size ≥5μm accounts for 0% of the volume.

[0167] The polycarbonate powder is an aromatic polycarbonate powder with a weight-average molecular weight of 24,700.

[0168] 2. Preparation of stabilizer composition: Same as in Example 1.

[0169] 3. Purification of polycarbonate solution:

[0170] (A) Add 6400 ppm of the above stabilizer composition to a polycarbonate dichloromethane solution (concentration of 20 wt%, weight average molecular weight of 26000) to obtain a mixture;

[0171] (B) High-temperature steam at 200°C is injected into the above mixture to remove dichloromethane, yielding solid polycarbonate.

[0172] Example 7

[0173] 1. Stabilizer composition raw material formulation:

[0174] N,N′-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine: 7.8%;

[0175] Triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate]: 2.1%;

[0176] Pentaerythritol diisodecyl diphosphite: 8.2%;

[0177] N,N-Bis(hydrogenated palm oil alkyl)hydroxylamine: 1.5%;

[0178] Synthetic magnesium aluminum hydrotalcite: 3.4%;

[0179] Polycarbonate powder: Balance;

[0180] in,

[0181] The specifications of the synthetic magnesium aluminum hydrotalcite are as follows: MgO / Al2O3 molar ratio is 4.3; average particle size D50 is 0.42μm; particle volume percentage of particles ≤1μm is 95.4%; and particle volume percentage of particles ≥5μm is 0%.

[0182] The polycarbonate powder is an aromatic polycarbonate powder with a weight-average molecular weight of 27,000.

[0183] 2. Preparation of stabilizer composition: Same as in Example 1.

[0184] 3. Purification of polycarbonate solution:

[0185] (A) Add 5600 ppm of the above stabilizer composition to a polycarbonate dichloromethane solution (concentration of 20 wt%, weight average molecular weight of 26000) to obtain a mixture;

[0186] (B) High-temperature steam at 200°C is injected into the above mixture to remove dichloromethane, yielding solid polycarbonate.

[0187] Example 8

[0188] 1. Stabilizer composition raw material formulation:

[0189] N,N′-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine: 8.7%;

[0190] Diethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate]: 1.8%;

[0191] Pentaerythritol diisotridecyl diphosphite: 7.5%;

[0192] N,N-Bis(hydrogenated palm oil alkyl)hydroxylamine: 2.3%;

[0193] Synthetic magnesium aluminum hydrotalcite: 3.7%;

[0194] Polycarbonate powder: Balance;

[0195] in,

[0196] The specifications of the synthetic magnesium aluminum hydrotalcite are as follows: MgO / Al2O3 molar ratio is 4.3; average particle size D50 is 0.42μm; particle volume percentage of particles ≤1μm is 95.4%; and particle volume percentage of particles ≥5μm is 0%.

[0197] The polycarbonate powder is an aromatic polycarbonate powder with a weight-average molecular weight of 27,000.

[0198] 2. Preparation of stabilizer composition: Same as in Example 1.

[0199] 3. Purification of polycarbonate solution:

[0200] (A) Add 5900 ppm of the above stabilizer composition to a polycarbonate dichloromethane solution (concentration of 20 wt%, weight average molecular weight of 26000) to obtain a mixture;

[0201] (B) High-temperature steam at 200°C is injected into the above mixture to remove dichloromethane, yielding solid polycarbonate.

[0202] Example 9

[0203] 1. Stabilizer composition raw material formulation:

[0204] N,N′-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine: 9.3%;

[0205] Triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate]: 2.4%;

[0206] Pentaerythritol diisodecyl diphosphite: 7.2%;

[0207] N,N-bis(hydrogenated tallow alkyl)hydroxylamine: 1.4%;

[0208] Synthetic magnesium aluminum hydrotalcite: 3.9%;

[0209] Polycarbonate powder: Balance;

[0210] in,

[0211] The specifications of the synthetic magnesium aluminum hydrotalcite are as follows: MgO / Al2O3 molar ratio is 4.3; average particle size D50 is 0.42μm; particle volume percentage of particles ≤1μm is 95.4%; and particle volume percentage of particles ≥5μm is 0%.

[0212] The polycarbonate powder is an aromatic polycarbonate powder with a weight-average molecular weight of 27,000.

[0213] 2. Preparation of stabilizer composition: Same as in Example 1.

[0214] 3. Purification of polycarbonate solution:

[0215] (A) Add 6300 ppm of the above stabilizer composition to a polycarbonate dichloromethane solution (concentration of 20 wt%, weight average molecular weight of 26000) to obtain a mixture;

[0216] (B) High-temperature steam at 200°C is injected into the above mixture to remove dichloromethane, yielding solid polycarbonate.

[0217] Example 10

[0218] 1. Stabilizer composition raw material formulation:

[0219] N,N′-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine: 8.2%;

[0220] Triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate]: 2.0%;

[0221] Pentaerythritol diisodecyl diphosphite: 8.8%;

[0222] N,N-bis(hydrogenated tallow alkyl)hydroxylamine: 1.9%;

[0223] Synthetic magnesium aluminum hydrotalcite: 3.5%;

[0224] Polycarbonate powder: Balance;

[0225] in,

[0226] The specifications of the synthetic magnesium aluminum hydrotalcite are as follows: MgO / Al2O3 molar ratio is 4.24; average particle size D50 is 0.47μm; particle size ≤1μm accounts for 91.7% of the volume; and particle size ≥5μm accounts for 0% of the volume.

[0227] The polycarbonate powder is an aromatic polycarbonate powder with a weight-average molecular weight of 30,800.

[0228] 2. Preparation of stabilizer composition: Same as in Example 1.

[0229] 3. Purification of polycarbonate solution:

[0230] (A) Add 5750 ppm of the above stabilizer composition to a polycarbonate dichloromethane solution (concentration of 20 wt%, weight average molecular weight of 26000) to obtain a mixture;

[0231] (B) High-temperature steam at 200°C is injected into the above mixture to remove dichloromethane, yielding solid polycarbonate.

[0232] Example 11

[0233] 1. Stabilizer composition raw material formulation:

[0234] N,N′-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine: 8.9%;

[0235] Triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate]: 2.1%;

[0236] Pentaerythritol diisodecyl diphosphite: 7.6%;

[0237] Amine, bis(hydrogenated rapeseed oil alkyl)methyl, N-oxide: 2.0%;

[0238] Synthetic magnesium aluminum hydrotalcite: 3.8%;

[0239] Polycarbonate powder: Balance;

[0240] in,

[0241] The specifications of the synthetic magnesium aluminum hydrotalcite are as follows: MgO / Al2O3 molar ratio is 4.24; average particle size D50 is 0.47μm; particle size ≤1μm accounts for 91.7% of the volume; and particle size ≥5μm accounts for 0% of the volume.

[0242] The polycarbonate powder is an aromatic polycarbonate powder with a weight-average molecular weight of 30,800.

[0243] 2. Preparation of stabilizer composition: Same as in Example 1.

[0244] 3. Purification of polycarbonate solution:

[0245] (A) Add 6250 ppm of the above stabilizer composition to a polycarbonate dichloromethane solution (concentration of 20 wt%, weight average molecular weight of 26000) to obtain a mixture;

[0246] (B) High-temperature steam at 200°C is injected into the above mixture to remove dichloromethane, yielding solid polycarbonate.

[0247] Example 12

[0248] 1. Stabilizer composition raw material formulation:

[0249] N,N′-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine: 8.5%;

[0250] Triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate]: 2.2%;

[0251] Pentaerythritol diisodecyl diphosphite: 8.5%;

[0252] N,N-Bis(hydrogenated palm oil alkyl)hydroxylamine: 2.1%;

[0253] Synthetic magnesium aluminum hydrotalcite: 3.7%;

[0254] Polycarbonate powder: Balance;

[0255] in,

[0256] The specifications of the synthetic magnesium aluminum hydrotalcite are as follows: MgO / Al2O3 molar ratio is 4.24; average particle size D50 is 0.47μm; particle size ≤1μm accounts for 91.7% of the volume; and particle size ≥5μm accounts for 0% of the volume.

[0257] The polycarbonate powder is an aromatic polycarbonate powder with a weight-average molecular weight of 24,700.

[0258] 2. Preparation of stabilizer composition: Same as in Example 1.

[0259] 3. Purification of polycarbonate solution:

[0260] (A) Add 6050 ppm of the above stabilizer composition to a polycarbonate dichloromethane solution (concentration of 20 wt%, weight average molecular weight of 26000) to obtain a mixture;

[0261] (B) High-temperature steam at 200°C is injected into the above mixture to remove dichloromethane, yielding solid polycarbonate.

[0262] Comparative Example 1

[0263] The method was implemented according to Example 3, except that N,N′-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine was omitted from the stabilizer composition, and the amount omitted was made up with polycarbonate powder (the same applies to other comparative examples).

[0264] Comparative Example 2

[0265] The method was implemented according to Example 3, except that the triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate] was replaced with antioxidant 1010 in the stabilizer composition.

[0266] Comparative Example 3

[0267] The method was carried out according to Example 3, except that the diethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate was omitted from the stabilizer composition.

[0268] Comparative Example 4

[0269] The method was implemented according to Example 3, except that N,N′-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine was replaced with triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate] in the stabilizer composition, that is, all hindered phenols were replaced with a single triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate].

[0270] Comparative Example 5

[0271] The method was implemented according to Example 3, except that the diethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate] was replaced with N,N′-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine in the stabilizer composition, that is, all the hindered phenols were replaced with a single N,N′-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine.

[0272] Comparative Example 6

[0273] The method was implemented according to Example 3, except that pentaerythritol diisodecyl diphosphite was replaced with antioxidant 168 in the stabilizer composition.

[0274] Comparative Example 7

[0275] The method was implemented according to Example 3, except that pentaerythritol diisodecyl diphosphite was replaced with antioxidant PEP-36 in the stabilizer composition.

[0276] Comparative Example 8

[0277] The method was implemented according to Example 3, except that pentaerythritol diisodecyl diphosphite was omitted from the stabilizer composition.

[0278] Comparative Example 9

[0279] The method was implemented according to Example 3, except that N,N-bis(hydrogenated palm oil alkyl)hydroxylamine was replaced with antioxidant 136 in the stabilizer composition.

[0280] Comparative Example 10

[0281] The method was implemented according to Example 3, except that N,N-bis(hydrogenated palm oil alkyl) hydroxylamine was omitted from the stabilizer composition.

[0282] Comparative Example 11

[0283] The method was implemented according to Example 3, except that the synthetic magnesium aluminum hydrotalcite was replaced with calcium stearate acid absorber in the stabilizer composition.

[0284] Comparative Example 12

[0285] The method was implemented according to Example 3, except that the synthetic magnesium aluminum hydrotalcite was omitted from the stabilizer composition.

[0286] Product Testing :

[0287] The polycarbonates obtained in each example and comparative example were dried at 120°C for 4 hours, and then subjected to three extrusion evaluations and three dwell injection molding evaluations. The test results are shown in Table 1.

[0288] Evaluation of Triple Extrusion: Using a Nanjing JENT SHJ-36 twin-screw extruder at an extrusion temperature of 280℃, dried polycarbonate was extruded three times consecutively to obtain extruded granules. The yellow index of the extruded granules obtained after each extrusion was tested.

[0289] Evaluation of injection molding dwell time: Using a Guangdong Yizumi UN90SK injection molding machine, with an injection temperature of 300℃ and a mold temperature of 80℃, dried polycarbonate was directly injected and then injected with a 10-minute dwell time in the barrel to obtain injection-molded sheets with a thickness of 3mm. The yellow index and haze of the injection-molded sheets obtained under the two injection molding methods were tested.

[0290] Yellow Index Test: Performed using a Konica Minolta CM-5 spectrophotometer according to ASTM E313. Extruded granules were tested using the reflectance method, and injection-molded sheets were tested using the transmission method. A higher yellow index indicates a deeper yellow color.

[0291] Haze test: Performed using a Shanghai Instrument & Electronics SGW-820 haze meter according to ASTM D1003. Higher haze values ​​indicate lower transparency.

[0292] Table 1: Test results of each embodiment and comparative example

[0293]

[0294] As can be seen from the test results in the table above, the stabilizer compositions of the various embodiments of the present invention, after being applied in the solvent removal process of the polycarbonate solution, result in polycarbonate particles with low yellow index after subsequent multiple extrusion processes, and flakes with low yellow index and low haze after subsequent high-temperature injection molding and high-temperature dwell injection molding processes, which are superior to the comparative examples. This demonstrates that the stabilizer compositions of the present invention, after being applied in the solvent removal process of the polycarbonate solution, can provide protection for polycarbonate during high-temperature treatment (solvent removal, extrusion, and injection molding, etc.), resulting in excellent anti-yellowing properties and good heat resistance of polycarbonate during high-temperature processes.

[0295] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of these embodiments are merely to aid in understanding the method and core ideas of the present invention, including the best mode, and to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements similar to those expressed in the claims, or if they include equivalent structural elements that are not substantially different from those expressed in the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A stabilizer composition, characterized in that, By weight percentage, including: Multifunctional hindered phenolic antioxidant: 7.2%–9.3%; High-temperature resistant color-discoloration hindered phenolic antioxidant: 1.8%–2.4%; Phenol-free, high-phosphorus liquid spirocyclic phosphite antioxidant: 7.2%–9.3%; Carbon free radical scavenger: 1.4%–2.4%; Inorganic acid absorbent: 3.2%–3.9%; Polycarbonate powder: Balance; in, The multifunctional hindered phenolic antioxidant is N,N′-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine; The high-temperature resistant color-discoloration-hindering phenolic antioxidant is triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate].

2. The stabilizer composition according to claim 1, characterized in that, The phenol-free, high-phosphorus liquid spirocyclic phosphite antioxidant is at least one of pentaerythritol diisodecyl diphosphite and pentaerythritol diisodecithyl diphosphite.

3. The stabilizer composition according to claim 1, characterized in that, The carbon radical scavenger is N,N-bis(C 16 -C 18 Alkyl) hydroxylamine, amine, bis(C) 14 -C 24 At least one of alkyl(methyl) or N-oxide.

4. The stabilizer composition according to claim 1, characterized in that, The inorganic acid absorbent is synthetic magnesium aluminum hydrotalcite.

5. The stabilizer composition according to claim 4, characterized in that, The specifications of the synthetic magnesium aluminum hydrotalcite are as follows: MgO / Al2O3 molar ratio of 4 to 5; average particle size D50 of 0.3 to 0.6 μm; particle volume percentage of particles ≤1 μm ≥85%; and particle volume percentage of particles ≥5 μm ≥0%.

6. A method for preparing a stabilizer composition according to any one of claims 1 to 5, characterized in that, include: A stabilizer composition is obtained by mixing a multifunctional hindered phenolic antioxidant, a high-temperature resistant color-changing hindered phenolic antioxidant, a phenol-free high-phosphorus liquid spirocyclic phosphite antioxidant, a carbon free radical scavenger, an inorganic acid absorber, and polycarbonate powder.

7. The preparation method according to claim 6, characterized in that, The mixing sequence is as follows: first, the polycarbonate powder and the solid additives among the above additives are mixed to obtain a solid mixture; then, the liquid additives among the above additives are sprayed into the solid mixture to obtain a stabilizer composition.

8. A method for purifying a polycarbonate solution, characterized in that, include: (A) A polycarbonate solution is mixed with a stabilizer composition to obtain a mixture; (B) Remove the solvent from the mixture obtained in step (A) to obtain polycarbonate; The stabilizer composition is any one of the stabilizer compositions according to claims 1 to 5 or is prepared by any one of the preparation methods according to claims 6 to 7.

9. The purification method according to claim 8, characterized in that, Based on the polycarbonate in the polycarbonate solution, the amount of stabilizer composition added is 5500-6500 ppm.

10. A method for preparing polycarbonate, characterized in that, include: S1. Prepare a polycarbonate solution; S2. The polycarbonate solution is purified to obtain polycarbonate; The purification is performed using the purification method described in any one of claims 8 to 9.

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