Solid bisphenol A-bis (diphenyl phosphate) as well as preparation method and application thereof

Abstract

The invention relates to a preparation method of solid bisphenol A-bis (diphenyl phosphate), which comprises the following steps: (1) carrying out esterification reaction on phosphorus oxychloride and bisphenol A in the presence of a catalyst; (2) adding phenol, and carrying out an end-capping reaction to obtain liquid bisphenol A-bis (diphenyl phosphate); and (3) dissolving the liquid bisphenol A-bis (diphenyl phosphate) in ethanol, freezing, and freeze-drying in vacuum to obtain the solid bisphenol A-bis (diphenyl phosphate). The solid bisphenol A-bis (diphenyl phosphate) obtained by the preparation method disclosed by the invention is convenient to store, has better performance in a flame retardant test, and can improve the mechanical properties of materials.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical industry, relates to C07F9 / 6574, and particularly relates to a preparation method of halogen-free phosphorus flame retardant, and particularly relates to a solid bisphenol A-bis(diphenyl phosphate) and a preparation method and application thereof. BACKGROUND

[0002] Bisphenol A-bis(diphenyl phosphate) (BDP for short) is an important phosphorus flame retardant, and has good matrix compatibility, is not easy to volatilize, is low in toxicity, has good and relatively long-lasting flame retardant effect. At present, various phosphate flame retardants have been developed. The first generation of triphenyl phosphate has good flame retardant performance, but its carcinogenicity and volatility limit its use. In order to solve this problem, BDP and resorcinol bis(diphenyl) phosphate (RDP) have been developed. At present, the main BDP manufacturers are Zhejiang Wansheng Chemical Co., Ltd., Japan ADEKA and Shandong Xuru New Material Co., Ltd. The industrial production of BDP is generally that trichloro-phosphine reacts with bisphenol A under the catalysis of Lewis acid to obtain bisphenol A tetrachloro bisphosphate, and then the end-capping reaction is carried out by using phenol to obtain BDP. The addition of BDP into engineering plastics is a great success in improving the flame retardant performance, and is suitable for flame-retardant oxygen-containing engineering plastics such as polycarbonate (PC), acrylonitrile-butadiene-styrene copolymer (ABS), polypropylene (PP) and polybutylene terephthalate (PBT).

[0003] Although BDP has a wide application background and broad market, BDP flame retardant products are almost high-viscosity liquids, which limits its application. The liquid BDP of commercial products has the following shortcomings: 1. A liquid quantitative pressure pump is needed when used; 2. Heat preservation is needed to ensure fluidity and prevent solidification during transportation and long-term storage; 3. Plasticizing effect is obvious, which reduces the heat distortion temperature of the base material; and 4. Long-term storage is easy to oxidize.

[0004] Patent CN101671439B discloses a method for preparing high-molecular-weight bisphenol A tetraphenyl bisphosphate, specifically a method for synthesizing solid BDP (SBDP). This reaction generates highly polymerized SBDP through transesterification. Although solid BDP is obtained and meets industrial production requirements in terms of product quality and environmental protection, the reaction conditions are difficult and the cost is high. Patent EP1264855A1 proposes using porous SiO2 (silica) to adsorb liquid BDP, producing a free-flowing powder to overcome the aforementioned shortcomings of liquid BDP. However, this method yields a product with a BDP content of 60-70%, reducing the flexibility of formulation and affecting the physical properties of downstream products. Shandong Xurui New Material Co., Ltd. disclosed a method for crystallizing solid phosphate ester flame retardants in patent CN117986293A. Specifically, a liquid product is added dropwise to water, and after the addition is complete, it is filtered, pulverized, dried, and crystallized to obtain a solid powdered phosphate ester flame retardant. This method reduces safety risks, eliminates volatile solvents, and effectively reduces pollution, but the process loss is relatively high. Currently, the main disclosed methods convert liquid products into solids through crystallization, but this yield is lower and the process is more complex.

[0005] To address the aforementioned issues, existing technologies urgently need improvement. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a solid bisphenol A-bis(diphenyl phosphate), its preparation method, and its applications. The solid bisphenol A-bis(diphenyl phosphate) obtained by the preparation method is easy to store, performs better in flame retardant tests, and can improve the mechanical properties of materials.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a method for preparing solid bisphenol A-bis(diphenyl phosphate), the method comprising: (1) Phosphorus oxychloride and bisphenol A undergo esterification in the presence of a catalyst; (2) Phenol was added to carry out the end-capping reaction to obtain liquid bisphenol A-bis(diphenyl phosphate); (3) Dissolve liquid bisphenol A-bis(diphenyl phosphate) in ethanol, freeze and freeze dry under vacuum to obtain solid bisphenol A-bis(diphenyl phosphate).

[0008] Preferably, in step (3), the mass ratio of the liquid bisphenol A-bis(diphenyl phosphate) to the ethanol is 1:(0.1~0.5), more preferably 1:(0.1~0.3), and even more preferably 1:0.2.

[0009] Preferably, the freezing temperature is -60 ~ -100℃, and more preferably -80℃.

[0010] Preferably, the vacuum freeze-drying temperature is -60 ~ -100℃; the drying time is 4 ~ 8 hours.

[0011] Preferably, in the step (1), the catalyst is selected from one or more of anhydrous magnesium chloride, anhydrous aluminum chloride, zinc chloride, iron chloride, titanium tetrachloride, preferably anhydrous magnesium chloride.

[0012] Preferably, the molar ratio of the phosphorus oxychloride to the catalyst is (30 ~ 300) : 1, preferably (45 ~ 260) : 1.

[0013] Preferably, in the step (1), the esterification reaction temperature is 80 ~ 120℃.

[0014] Preferably, the esterification reaction time is 4 ~ 6 hours.

[0015] Preferably, the molar ratio of the phosphorus oxychloride to the bisphenol A is (3 ~ 7) : 1, preferably (4 ~ 5) : 1.

[0016] Preferably, the step (1) specifically comprises: pre-mixing the phosphorus oxychloride and the catalyst; and then adding the bisphenol A to perform the esterification reaction.

[0017] Preferably, the pre-mixing temperature is 40 ~ 50℃.

[0018] Preferably, the temperature is controlled at 60 ~ 80℃ when the bisphenol A is added.

[0019] Preferably, the step (1) further comprises: after the esterification reaction is completed, removing the excess phosphorus oxychloride by vacuum distillation.

[0020] Preferably, the pressure during the vacuum distillation is -0.1 MPa, the time is 1 ~ 2 hours, and the temperature is 100 ~ 140℃.

[0021] Preferably, during the reaction process of the step (1), nitrogen protection is performed until the nitrogen protection is removed after the esterification reaction is completed.

[0022] Preferably, in the step (2), the temperature is controlled at 120 ~ 140℃, preferably 120℃, when the phenol is added.

[0023] Preferably, the speed is controlled at 1.5 ~ 2 g / min when the phenol is added.

[0024] Preferably, after the phenol is added, the end-capping reaction temperature is 140 ~ 160℃.

[0025] Preferably, the reaction time of the end-capping reaction is 4-6 hours after the phenol is added.

[0026] Preferably, the molar ratio of the phosphorus oxychloride to the phenol is 1:(1-2), preferably 1:(1-1.5).

[0027] Preferably, after step (2), the method further comprises: after the end-capping reaction is completed, removing the excess phenol by distillation under reduced pressure, dissolving in a solvent, and then removing the solvent after alkaline washing and water washing to obtain liquid bisphenol A-bis(diphenyl phosphate).

[0028] Preferably, the pressure during the distillation under reduced pressure is -0.1 MPa, the time is 1-2 hours, and the temperature of the distillation under reduced pressure is 70-90°C, preferably 80°C.

[0029] Preferably, the solvent is selected from aromatic hydrocarbons and / or alkanes, preferably aromatic hydrocarbons and alkanes.

[0030] Preferably, the aromatic hydrocarbon solvent is selected from one or more of toluene, o-xylene, m-xylene, p-xylene, chlorobenzene, mesitylene, preferably toluene.

[0031] Preferably, the alkane solvent is selected from one or more of methylcyclohexane, cyclopentane, n-heptane, n-hexane, preferably methylcyclohexane.

[0032] Preferably, the mass ratio of the aromatic hydrocarbon to the alkane is 1:(0.1-5), preferably 1:(0.5-2).

[0033] Preferably, the temperature is controlled to be 20-30°C when dissolving in the solvent.

[0034] Preferably, the water washing temperature is 50-90°C, preferably 70°C.

[0035] Preferably, the solvent removal is removal of the excess solvent under reduced pressure.

[0036] Preferably, the reduced pressure is reduced to -0.1 MPa.

[0037] The application also provides a solid bisphenol A-bis(diphenyl phosphate) prepared by the preparation method described in any of the above.

[0038] Preferably, the solid bisphenol A-bis(diphenyl phosphate) comprises the following components by mass: bisphenol A-bis(diphenyl phosphate) monomer 84-89%, bisphenol A-bis(diphenyl phosphate) dimer 10-13%, The mass ratio of the bisphenol A-bis(diphenyl phosphate) monomer to the bisphenol A-bis(diphenyl phosphate) dimer is (6~9):1.

[0039] Preferably, the solid bisphenol A-bis(diphenyl phosphate) further comprises the following components in parts by weight: Bisphenol A-bis(diphenyl phosphate) trimer 0.6~2.0%, Triphenyl phosphate 0.4~0.5%.

[0040] Preferably, the solid bisphenol A-bis(diphenyl phosphate) comprises the following components in parts by weight: Bisphenol A-bis(diphenyl phosphate) monomer 85-88%, Bisphenol A-bis(diphenyl phosphate) dimer 10-12%, Bisphenol A-bis(diphenyl phosphate) trimer 1.1~1.5%, Triphenyl phosphate 0.45~0.5%.

[0041] Preferably, the mass ratio of the bisphenol A-bis(diphenyl phosphate) monomer to the bisphenol A-bis(diphenyl phosphate) dimer is (6.7~8.7):1.

[0042] The present invention also provides the application of solid bisphenol A-bis(diphenyl phosphate) prepared according to any of the above preparation methods in modified flame retardant materials.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a method for preparing solid bisphenol A-bis(diphenyl phosphate), eliminating the drawback of reduced mechanical properties after the addition of traditional liquid bisphenol A-bis(diphenyl phosphate) to materials. Solid bisphenol A-bis(diphenyl phosphate) increases its stability and avoids problems such as oxidation during long-term storage. Furthermore, by controlling the reaction temperature (80~120℃) between phosphorus oxychloride and bisphenol A, the degree of polymerization of bisphenol A-bis(diphenyl phosphate) can be precisely controlled, optimizing the ratio of BDP monomer to BDP dimer.

[0044] 2. The solid bisphenol A-bis(diphenyl phosphate) prepared by the method of this invention exhibits excellent performance in flame retardant tests and can improve the mechanical properties of the material. Solid bisphenol A-bis(diphenyl phosphate) enables the PC / ABS system to achieve a V-0 flame retardant rating, and comprehensively improves mechanical properties, with a higher limiting oxygen index. Increasing the proportion of BDP monomer and BDP dimer optimizes flexural modulus and limiting oxygen index, but slightly reduces impact toughness; decreasing the proportion of BDP monomer and BDP dimer optimizes impact toughness, but slightly reduces flexural modulus. In particular, when the ratio of BDP monomer to BDP dimer is moderate, the flame retardant and mechanical properties of the material are synergistically optimized. Therefore, the degree of polymerization ratio of solid bisphenol A-bis(diphenyl phosphate) can be balanced according to the actual application scenario. Detailed Implementation

[0045] To make the technical solution and beneficial effects of the present invention more apparent and understandable, a detailed description is provided below by listing specific embodiments. Unless otherwise defined, the technical and scientific terms used herein have the same meanings as those in the technical field to which this application pertains.

[0046] This invention provides a method for preparing solid bisphenol A-bis(diphenyl phosphate), the method comprising: (1) Phosphorus oxychloride and bisphenol A undergo esterification in the presence of a catalyst; (2) Phenol was added to carry out the end-capping reaction to obtain liquid bisphenol A-bis(diphenyl phosphate); (3) Dissolve liquid bisphenol A-bis(diphenyl phosphate) in ethanol, freeze and freeze dry under vacuum to obtain solid bisphenol A-bis(diphenyl phosphate).

[0047] In some embodiments, in step (3), the mass ratio of the liquid bisphenol A-bis(diphenyl phosphate) to the ethanol is 1:(0.1~0.5), for example, 1:0.1, 1:0.11, 1:0.12, 1:0.13, 1:0.14, 1:0.15, 1:0.16, 1:0.17, 1:0.18, 1:0.19, 1:0.2, 1:0.3, 1:0.4, 1:0.5, etc.

[0048] In some embodiments, in step (3), the mass ratio of the liquid bisphenol A-bis(diphenyl phosphate) to the ethanol is 1:(0.1~0.3).

[0049] In some embodiments, in step (3), the mass ratio of the liquid bisphenol A-bis(diphenyl phosphate) to the ethanol is 1:0.2.

[0050] In some embodiments, in step (3), the freezing temperature is -60 ~ -100℃.

[0051] In some embodiments, in step (3), the freezing temperature is -70 ~ -90°C.

[0052] In some embodiments, in step (3), the freezing temperature is -80°C.

[0053] In some embodiments, in step (3), the drying temperature of the vacuum freeze drying is -60 ~ -100℃, and the drying time is 4 ~ 8 hours.

[0054] In some embodiments, in step (3), the drying temperature of the vacuum freeze drying is -70 to -90°C, and the drying time is 5 to 7 hours.

[0055] In some embodiments, in step (3), the drying temperature of the vacuum freeze-drying is -80°C and the drying time is 6 hours.

[0056] In some embodiments, in step (1), the catalyst is selected from one or more of anhydrous magnesium chloride, anhydrous aluminum chloride, zinc chloride, ferric chloride, and titanium tetrachloride.

[0057] In some embodiments, in step (1), the catalyst is selected from anhydrous magnesium chloride.

[0058] In some embodiments, in step (1), the molar ratio of phosphorus oxychloride to the catalyst is (30~300):1.

[0059] In some embodiments, in step (1), the molar ratio of phosphorus oxychloride to the catalyst is (45~260):1.

[0060] In some embodiments, in step (1), the molar ratio of phosphorus oxychloride to the catalyst is (100~200):1, for example, 100:1, 105:1, 110:1, 115:1, 120:1, 121:1, 122:1, 123:1, 124:1, 124.1:1, 124.2:1, 124.3:1, 124.4:1, 124.5:1, 124.6:1, 124.7:1, 124.8:1, 124.9:1, 125:1, 130:1, 135:1, 140:1, 145:1, 150:1, 160:1, 170:1, 180:1, 190:1, 200:1, etc.

[0061] In some embodiments, the reaction temperature of the esterification reaction in step (1) is 80~120°C.

[0062] In some embodiments, the reaction time of the esterification reaction in step (1) is 4 to 6 hours.

[0063] In some embodiments, in step (1), the molar ratio of phosphorus oxychloride to bisphenol A is (3~7):1. For example, 3:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, 3.6:1, 3.7:1, 3.8:1, 3.9:1, 4:1, 4.1:1, 4.2:1, 4.3:1, 4.4:1, 4.5:1, 4.6:1, 4.61:1, 4.62:1, 4.63:1, 4.64:1, 4.65:1, 4.66:1, 4.67:1, 4... 68:1, 4.69:1, 4.7:1, 4.8:1, 4.9:1, 5:1, 5.1:1, 5.2:1, 5.3:1, 5.4:1, 5.5:1, 5.6:1, 5.7:1, 5.8:1, 5.9:1, 6:1, 6.1:1, 6.2:1, 6.3:1, 6.4:1, 6.5:1, 6.6:1, 6.7:1, 6.8:1, 6.9:1, 7:1, etc.

[0064] In some embodiments, in step (1), the molar ratio of phosphorus oxychloride to bisphenol A is (4~5):1.

[0065] In some embodiments, step (1) specifically includes: premixing phosphorus oxychloride with a catalyst; then adding bisphenol A to carry out an esterification reaction.

[0066] In some embodiments, the premixing temperature is 40~50°C.

[0067] In some embodiments, the premixing temperature is 40°C.

[0068] In some embodiments, the temperature is controlled at 60-80°C when the bisphenol A is added.

[0069] In some embodiments, the temperature is controlled at 60°C when the bisphenol A is added.

[0070] In some embodiments, step (1) is followed by: after the esterification reaction is complete, removing excess phosphorus oxychloride by vacuum distillation.

[0071] In some embodiments, the pressure during vacuum distillation is -0.1 MPa, the time is 1 to 2 hours, and the temperature is 100 to 140°C, such as 100°C, 110°C, 120°C, 130°C, 140°C, etc.

[0072] In some embodiments, the temperature during vacuum distillation is 110°C.

[0073] In some embodiments, nitrogen protection is provided during the reaction process of step (1) until the esterification reaction is complete, after which the nitrogen protection is removed.

[0074] In some embodiments, in step (2), the temperature is controlled at 120~140°C when phenol is added.

[0075] In some embodiments, in step (2), the temperature is controlled at 120°C when phenol is added.

[0076] In some embodiments, the rate at which phenol is added in step (2) is controlled to be 1.5~2 g / min.

[0077] In some embodiments, after the addition of phenol is completed, the reaction temperature of the capping reaction is 140~160°C.

[0078] In some embodiments, after the addition of phenol, the capping reaction takes 4 to 6 hours.

[0079] In some embodiments, the molar ratio of phosphorus oxychloride to phenol is 1:(1~2), for example: 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.31, 1:1.32, 1:1.33, 1:1.34, 1:1.35, 1:1.36, 1:1.37, 1:1.38, 1:1.39, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2.0, etc.

[0080] In some embodiments, the molar ratio of phosphorus oxychloride to phenol is 1:(1~1.5).

[0081] In some embodiments, step (2) is followed by: after the end-capping reaction is complete, removing excess phenol by vacuum distillation, then dissolving it in a solvent, and then washing it with alkali and water to remove the solvent, thereby obtaining liquid bisphenol A-bis(diphenyl phosphate).

[0082] In some embodiments, the pressure during vacuum distillation is -0.1 MPa, the time is 1 to 2 hours, and the temperature during vacuum distillation is 70 to 90°C.

[0083] In some embodiments, the temperature of the vacuum distillation is 80°C.

[0084] In some embodiments, the solvent is selected from aromatic hydrocarbons and / or alkanes.

[0085] In some embodiments, the solvent is selected from aromatic hydrocarbons and alkanes.

[0086] In some embodiments, the solvent is selected from aromatic hydrocarbons and alkanes in a mass ratio of 1:(0.1~5), for example, 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1.0, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2.0, 1:3.0, 1:4.0, 1:5.0, etc.

[0087] In some embodiments, the solvent is selected from aromatic hydrocarbons and alkanes in a mass ratio of 1:(0.5~2).

[0088] In some embodiments, the solvent is selected from aromatic hydrocarbons and alkanes in a mass ratio of 1:(1~2).

[0089] In some embodiments, the solvent is selected from aromatic hydrocarbons and alkanes in a mass ratio of 1:1.

[0090] In some embodiments, the aromatic hydrocarbon solvent is selected from one or more of toluene, o-xylene, m-xylene, p-xylene, chlorobenzene, and mesitylene.

[0091] In some embodiments, the aromatic hydrocarbon solvent is selected from toluene.

[0092] In some embodiments, the alkane solvent is selected from one or more of methylcyclohexane, cyclopentane, n-heptane, and n-hexane.

[0093] In some embodiments, the alkane solvent is selected from methylcyclohexane.

[0094] In some embodiments, the solvent is selected from toluene and methylcyclohexane.

[0095] In some embodiments, the solvent is selected from toluene and methylcyclohexane in a mass ratio of 1:1.

[0096] In some embodiments, the temperature is controlled at 20~30°C when the solvent is added for dissolution, for example, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, etc.

[0097] In some embodiments, the temperature is controlled at 25°C when the solvent is added for dissolution.

[0098] In some embodiments, the water washing temperature is 50~90°C.

[0099] In some embodiments, the water washing temperature is 60~80℃, for example, 60℃, 61℃, 62℃, 63℃, 64℃, 65℃, 66℃, 67℃, 68℃, 69℃, 70℃, 71℃, 72℃, 73℃, 74℃, 75℃, 76℃, 77℃, 78℃, 79℃, 80℃, etc.

[0100] In some embodiments, the water washing temperature is 70°C.

[0101] In some embodiments, the desolventizing is the removal of excess solvent under reduced pressure.

[0102] In some embodiments, the pressure reduction is reduced to -0.1 MPa.

[0103] The present invention also provides a solid bisphenol A-bis(diphenyl phosphate) prepared according to any one of the above preparation methods.

[0104] In some embodiments, the solid bisphenol A-bis(diphenyl phosphate) comprises the following components in parts by weight: Bisphenol A-bis(diphenyl phosphate) monomer 84-89%, Bisphenol A-bis(diphenyl phosphate) dimer 10-13%, The mass ratio of the bisphenol A-bis(diphenyl phosphate) monomer to the bisphenol A-bis(diphenyl phosphate) dimer is (6~9):1, for example, 6:1, 6.1:1, 6.2:1, 6.3:1, 6.4:1, 6.5:1, 6.6:1, 6.7:1, 6.8:1, 6.9:1, 7.0:1, 7.1:1, 7.2:1, 7.3:1, 7.4:1, 7.5:1, 7.6:1, 7.7:1, 7.8:1, 7.9:1, 8.0:1, 8.1:1, 8.2:1, 8.3:1, 8.4:1, 8.5:1, 8.6:1, 8.65:1, 8.7:1, 8.8:1, 8.9:1, 9.0:1, etc.

[0105] In some embodiments, the solid bisphenol A-bis(diphenyl phosphate) further includes the following components in parts by weight: Bisphenol A-bis(diphenyl phosphate) trimer 0.6~2.0%, Triphenyl phosphate 0.4~0.5%.

[0106] In some embodiments, the solid bisphenol A-bis(diphenyl phosphate) comprises the following components in parts by weight: Bisphenol A-bis(diphenyl phosphate) monomer 85-88%, Bisphenol A-bis(diphenyl phosphate) dimer 10-12%, Bisphenol A-bis(diphenyl phosphate) trimer 1.1~1.5%, Triphenyl phosphate 0.45~0.5%.

[0107] In some embodiments, the mass ratio of the bisphenol A-bis(diphenyl phosphate) monomer to the bisphenol A-bis(diphenyl phosphate) dimer is (6.7~8.7):1.

[0108] The present invention also provides the application of solid bisphenol A-bis(diphenyl phosphate) prepared according to any of the above preparation methods in modified flame retardant materials.

[0109] Where specific experimental steps or conditions are not specified in the embodiments, they can be performed according to the conventional experimental steps or conditions described in the literature in this field. All materials used are commercially available conventional products, including but not limited to the materials used in the embodiments of this invention.

[0110] The method of the present invention will be described below through specific embodiments. It should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0111] Example 1 Add 0.6 g of anhydrous magnesium chloride and 120 g of phosphorus oxychloride to a four-necked flask. Heat to 40 °C and stir until the solid is completely dissolved. Heat to 60 °C and add 38.7 g of bisphenol A. After the addition is complete, heat to 80 °C and hold for 4 h. Then heat to 110 °C and reduce the pressure to -0.1 MPa for 1 h to remove excess phosphorus oxychloride. Heat to 120 °C and start adding 100 g of phenol dropwise. After the addition is complete within 1 h, heat to 140 °C and hold for 4 h. Cool to 80 °C and reduce the pressure to -0.1 MPa for 1 h to remove excess phenol. After cooling to room temperature, add 80 g of a mixed solvent of toluene and methylcyclohexane (mass ratio 1:1). Then add 50 mL of 10% NaOH solution to wash. Keep at 70 °C for half an hour and wash with water in layers. Finally, reduce the pressure to -0.1 MPa to remove excess water and solvent to obtain a colorless, transparent, viscous liquid, bisphenol A-bis(diphenyl phosphate).

[0112] The above-mentioned viscous liquid bisphenol A-bis(diphenyl phosphate) was dissolved in approximately 100g of ethanol solution (0.2 times its mass) to form a homogeneous phase. The solution was then placed in an ultra-low temperature freezer and frozen (-80°C). The solution was then placed in a freeze dryer and set at -80°C for 6 hours. The solvent was removed by vacuum freeze drying. Once the product solidified into a block, it was pulverized and sieved to obtain uniform solid granular powder, which is the solid bisphenol A-bis(diphenyl phosphate).

[0113] Example 2 Add 0.6 g of anhydrous magnesium chloride and 120 g of phosphorus oxychloride to a four-necked flask. Heat to 40 °C and stir until the solid is completely dissolved. Heat to 60 °C and add 38.7 g of bisphenol A. After the addition is complete, heat to 100 °C and hold for 4 hours. Then heat to 110 °C and reduce the pressure to -0.1 MPa for 1 hour to remove excess phosphorus oxychloride. Heat to 120 °C and start adding 100 g of phenol dropwise. After the addition is complete within 1 hour, heat to 140 °C and hold for 4 hours. Cool to 80 °C and reduce the pressure to -0.1 MPa for 1 hour to remove excess phenol. After cooling to room temperature, add 80 g of a mixed solvent of toluene and methylcyclohexane (mass ratio 1:1). Then add 50 mL of 10% NaOH solution for washing. Keep at 70 °C for half an hour and wash with water in layers. Finally, reduce the pressure to -0.1 MPa to remove excess water and solvent to obtain a colorless, transparent, viscous liquid, bisphenol A-bis(diphenyl phosphate).

[0114] The above-mentioned viscous liquid bisphenol A-bis(diphenyl phosphate) was dissolved in approximately 100g of ethanol solution (0.2 times its mass) to form a homogeneous phase. The solution was then placed in an ultra-low temperature freezer and frozen (-80°C). The solution was then placed in a freeze dryer and set at -80°C for 6 hours. The solvent was removed by vacuum freeze drying. Once the product solidified into a block, it was pulverized and sieved to obtain uniform solid granular powder, which is the solid bisphenol A-bis(diphenyl phosphate).

[0115] Example 3 Add 0.6 g of anhydrous magnesium chloride and 120 g of phosphorus oxychloride to a four-necked flask. Heat to 40 °C and stir until the solid is completely dissolved. Heat to 60 °C and add 38.7 g of bisphenol A. After the addition is complete, heat to 120 °C and hold for 4 hours. Then heat to 110 °C and reduce the pressure to -0.1 MPa for 1 hour to remove excess phosphorus oxychloride. Heat to 120 °C and start adding 100 g of phenol dropwise. After the addition is complete within 1 hour, heat to 140 °C and hold for 4 hours. Cool to 80 °C and reduce the pressure to -0.1 MPa for 1 hour to remove excess phenol. After cooling to room temperature, add 80 g of a mixed solvent of toluene and methylcyclohexane (mass ratio 1:1). Then add 50 mL of 10% NaOH solution to wash. Keep at 70 °C for half an hour and wash with water in layers. Finally, reduce the pressure to -0.1 MPa to remove excess water and solvent to obtain a colorless, transparent, viscous liquid, bisphenol A-bis(diphenyl phosphate).

[0116] The above-mentioned viscous liquid bisphenol A-bis(diphenyl phosphate) was dissolved in approximately 100g of ethanol solution (0.2 times its mass) to form a homogeneous phase. The solution was then placed in an ultra-low temperature freezer and frozen (-80°C). The solution was then placed in a freeze dryer and set at -80°C for 6 hours. The solvent was removed by vacuum freeze drying. Once the product solidified into a block, it was pulverized and sieved to obtain uniform solid granular powder, which is the solid bisphenol A-bis(diphenyl phosphate).

[0117] Comparative Example 1 Add 0.6 g of anhydrous magnesium chloride and 120 g of phosphorus oxychloride to a four-necked flask. Heat to 40 °C and stir until the solid is completely dissolved. Heat to 60 °C and add 38.7 g of bisphenol A. After the addition is complete, heat to 80 °C and hold for 4 h. Then heat to 110 °C and reduce the pressure to -0.1 MPa for 1 h to remove excess phosphorus oxychloride. Heat to 120 °C and start adding 100 g of phenol dropwise. After the addition is complete within 1 h, heat to 140 °C and hold for 4 h. Cool to 80 °C and reduce the pressure to -0.1 MPa for 1 h to remove excess phenol. After cooling to room temperature, add 80 g of a mixed solvent of toluene and methylcyclohexane (mass ratio 1:1). Then add 50 mL of 10% NaOH solution to wash. Keep at 70 °C for half an hour and wash with water in layers. Finally, reduce the pressure to -0.1 MPa to remove excess water and solvent to obtain a colorless, transparent, viscous liquid, BDP.

[0118] Comparative Example 2 Add 0.6 g of anhydrous magnesium chloride and 120 g of phosphorus oxychloride to a four-necked flask. Heat to 40 °C and stir until the solid is completely dissolved. Heat to 60 °C and add 38.7 g of bisphenol A. After the addition is complete, heat to 100 °C and hold for 4 hours. Then heat to 110 °C and reduce the pressure to -0.1 MPa for 1 hour to remove excess phosphorus oxychloride. Heat to 120 °C and start adding 100 g of phenol dropwise. After the addition is complete within 1 hour, heat to 140 °C and hold for 4 hours. Cool to 80 °C and reduce the pressure to -0.1 MPa for 1 hour to remove excess phenol. After cooling to room temperature, add 80 g of a mixed solvent of toluene and methylcyclohexane (mass ratio 1:1). Then add 50 mL of 10% NaOH solution to wash. Keep at 70 °C for half an hour and wash with water in layers. Finally, reduce the pressure to -0.1 MPa to remove excess water and solvent to obtain a colorless, transparent, viscous liquid, BDP.

[0119] Comparative Example 3 Add 0.6 g of anhydrous magnesium chloride and 120 g of phosphorus oxychloride to a four-necked flask. Heat to 40 °C and stir until the solid is completely dissolved. Heat to 60 °C and add 38.7 g of bisphenol A. After the addition is complete, heat to 120 °C and hold for 4 hours. Then heat to 110 °C and reduce the pressure to -0.1 MPa for 1 hour to remove excess phosphorus oxychloride. Heat to 120 °C and start adding 100 g of phenol dropwise. After the addition is complete within 1 hour, heat to 140 °C and hold for 4 hours. Cool to 80 °C and reduce the pressure to -0.1 MPa for 1 hour to remove excess phenol. After cooling to room temperature, add 80 g of a mixed solvent of toluene and methylcyclohexane (mass ratio 1:1). Then add 50 mL of 10% NaOH solution to wash. Keep at 70 °C for half an hour and wash with water in layers. Finally, reduce the pressure to -0.1 MPa to remove excess water and solvent to obtain a colorless, transparent, viscous liquid, BDP.

[0120] Comparative Example 4 Add 0.6 g of anhydrous magnesium chloride and 120 g of phosphorus oxychloride to a four-necked flask. Heat to 40 °C and stir until the solid is completely dissolved. Heat to 60 °C and add 38.7 g of bisphenol A. After the addition is complete, heat to 140 °C and hold for 4 hours. Then heat to 110 °C and reduce the pressure to -0.1 MPa for 1 hour to remove excess phosphorus oxychloride. Heat to 120 °C and start adding 100 g of phenol dropwise. After the addition is complete within 1 hour, heat to 140 °C and hold for 4 hours. Cool to 80 °C and reduce the pressure to -0.1 MPa for 1 hour to remove excess phenol. After cooling to room temperature, add 80 g of a mixed solvent of toluene and methylcyclohexane (mass ratio 1:1). Then add 50 mL of 10% NaOH solution to wash. Keep at 70 °C for half an hour and wash with water to separate the layers. Finally, reduce the pressure to -0.1 MPa to remove excess water and solvent to obtain a colorless, transparent, viscous liquid, BDP.

[0121] Experimental Example The final products prepared in Examples 1-3 and Comparative Examples 1-4 of this invention were separated and determined by high performance liquid chromatography. The contents of bisphenol A-bis(diphenyl phosphate) monomer (BDP monomer) and triphenyl phosphate (TPP) were determined by area normalization method. The results are shown in Table 1.

[0122] The detection was performed using high-performance liquid chromatography (HPLC) under the following conditions: Column: Eclipse XDB-C18, 4.6μm×250mm; Detector: Ultraviolet variable detector; Detection wavelength: 254nm; Column temperature: 25℃ (±2℃); Flow rate: 1.0~1.8 mL / min; Injection volume: 20 μL; Mobile phase: Mobile phase A: Acetonitrile, Mobile phase B: Water; The gradient elution procedure is as follows: .

[0123] Table 1. Results of BDP content detection

[0124] The platinum-cobalt color number of the product was determined using an SH810 fully automatic platinum-cobalt colorimeter; the phosphorus content of the product was measured using spectrophotometry; and the viscosity of the product was measured using an Anton Paar ViscoQC rotational viscometer. The results are shown in Table 2.

[0125] Table 2 Other parameter indicators

[0126] As shown in Tables 1 and 2, the ratio of BDP monomer to BDP dimer is mainly determined by the reaction temperature of phosphorus oxychloride with bisphenol A; the higher the temperature, the easier it is for polymers to form. At reaction temperatures of 80℃ to 120℃, the ratio of BDP monomer to BDP dimer is 6 to 9. When the esterification reaction temperature exceeds 120℃, reaching 140℃, the ratio of BDP monomer to BDP dimer becomes severely imbalanced, less than 6, and the sample becomes very sticky and severely yellow; therefore, no further testing was conducted.

[0127] The final products obtained from Examples 1-3 and Comparative Examples 1-3 of this invention were used to prepare modified flame-retardant materials according to the standard PC / ABS formulation. The main formulation included PC-1225, ABS-757K, BDP, MBS-722, antioxidants 1076 and 168, and PETS (pentaerythritol stearate). Flame-retardant and mechanical properties were tested. The PC / ABS formulation is shown in Table 3, and the test results of flame-retardant and mechanical properties are shown in Table 4.

[0128] Limiting oxygen index (%) test: The minimum oxygen concentration required for the material to sustain combustion is determined according to GB / T 2406.2-2009 standard.

[0129] Vertical burning test: Tested according to GB / T 8333-2022 standard.

[0130] Table 3 PC / ABS Formulation

[0131] Table 4. Test results of flame retardant and mechanical properties

[0132] As shown in Table 4, the solid bisphenol A-bis(diphenyl phosphate) prepared by the method of this invention exhibits improved flame retardant properties. Solid bisphenol A-bis(diphenyl phosphate) consistently achieves a V-0 flame retardant rating in the PC / ABS system, and also comprehensively improves mechanical properties, with a higher limiting oxygen index. For BDP monomers: increasing the proportion of BDP dimers optimizes flexural modulus and limiting oxygen index, but slightly reduces impact toughness; for BDP monomers: decreasing the proportion of BDP dimers optimizes impact toughness, but slightly reduces flexural modulus. Therefore, the degree of polymerization ratio of solid bisphenol A-bis(diphenyl phosphate) can be balanced according to the actual application scenario.

[0133] It should be understood that the above embodiments are exemplary and are not intended to encompass all possible implementations included in the claims. Various modifications and changes can be made to the above embodiments without departing from the scope of this disclosure. Similarly, the various technical features of the above embodiments can be arbitrarily combined to form other embodiments of the present invention that may not be explicitly described. Therefore, the above embodiments only illustrate several implementations of the present invention and do not limit the scope of protection of this patent.

Claims

1. A method for preparing solid bisphenol A-bis(diphenyl phosphate), characterized in that, The preparation method includes: (1) Phosphorus oxychloride and bisphenol A undergo esterification in the presence of a catalyst; (2) Phenol was added to carry out the end-capping reaction to obtain liquid bisphenol A-bis(diphenyl phosphate); (3) Dissolve liquid bisphenol A-bis(diphenyl phosphate) in ethanol, freeze and freeze dry under vacuum to obtain solid bisphenol A-bis(diphenyl phosphate).

2. The preparation method according to claim 1, characterized in that, In step (3), the mass ratio of the liquid bisphenol A-bis(diphenyl phosphate) to the ethanol is 1:(0.1~0.5), preferably 1:(0.1~0.3), and more preferably 1:0.2; Preferably, the freezing temperature is -60 ~ -100℃, and more preferably -80℃; Preferably, the drying temperature of the vacuum freeze drying is -60 ~ -100℃; the drying time is 4 ~ 8 hours.

3. The preparation method according to claim 1, characterized in that, In step (1), the catalyst is selected from one or more of anhydrous magnesium chloride, anhydrous aluminum chloride, zinc chloride, ferric chloride, and titanium tetrachloride, preferably anhydrous magnesium chloride; Preferably, the molar ratio of phosphorus oxychloride to the catalyst is (30~300):1, more preferably (45~260):

1.

4. The preparation method according to claim 1, characterized in that, In step (1), the reaction temperature of the esterification reaction is 80~120℃; Preferably, the esterification reaction takes 4 to 6 hours; Preferably, the molar ratio of phosphorus oxychloride to bisphenol A is (3~7):1, more preferably (4~5):

1.

5. The preparation method according to claim 1, characterized in that, The specific steps (1) include: premixing phosphorus oxychloride with a catalyst; then adding bisphenol A to carry out an esterification reaction; Preferably, the premixing temperature is 40~50℃; Preferably, the temperature is controlled at 60~80°C when adding the bisphenol A; Preferably, after step (1), the method further includes: after the esterification reaction is complete, removing excess phosphorus oxychloride by vacuum distillation; Preferably, the pressure during vacuum distillation is -0.1 MPa, the time is 1 to 2 hours, and the temperature is 100 to 140°C. Preferably, during the reaction process of step (1), nitrogen protection is provided until the esterification reaction is complete, after which the nitrogen protection is removed.

6. The preparation method according to claim 1, characterized in that, In step (2), the temperature is controlled at 120~140℃ when phenol is added, preferably 120℃; Preferably, the rate at which phenol is added is controlled to be 1.5~2 g / min; Preferably, after the addition of phenol is completed, the reaction temperature of the end-capping reaction is 140~160℃; Preferably, after the addition of phenol, the reaction time for the capping reaction is 4 to 6 hours; Preferably, the molar ratio of phosphorus oxychloride to phenol is 1:(1~2), more preferably 1:(1~1.5).

7. The preparation method according to claim 1, characterized in that, Step (2) also includes: after the end-capping reaction is complete, excess phenol is removed by vacuum distillation, then dissolved in a solvent, and after alkali washing and water washing, the solvent is removed to obtain liquid bisphenol A-bis(diphenyl phosphate); Preferably, the pressure during vacuum distillation is -0.1 MPa, the time is 1 to 2 hours, and the temperature during vacuum distillation is 70 to 90°C, preferably 80°C. Preferably, the solvent is selected from aromatic hydrocarbons and / or alkanes, and more preferably aromatic hydrocarbons and alkanes; Preferably, the aromatic hydrocarbon solvent is selected from one or more of toluene, o-xylene, m-xylene, p-xylene, chlorobenzene, and mesitylene, with toluene being the most preferred; Preferably, the alkane solvent is selected from one or more of methylcyclohexane, cyclopentane, n-heptane, and n-hexane, with methylcyclohexane being the most preferred. Preferably, the mass ratio of the aromatic hydrocarbon to the alkane is 1:(0.1~5), more preferably 1:(0.5~2); Preferably, the temperature is controlled at 20~30℃ when dissolving in the solvent; Preferably, the water washing temperature is 50~90℃, and more preferably 70℃; Preferably, the solvent removal is performed by removing excess solvent under reduced pressure; Preferably, the pressure reduction is reduced to -0.1 MPa.

8. A solid bisphenol A-bis(diphenyl phosphate) prepared by the preparation method according to any one of claims 1 to 7.

9. The solid bisphenol A-bis(diphenyl phosphate) according to claim 8, characterized in that, The solid bisphenol A-bis(diphenyl phosphate) comprises the following components in parts by weight: Bisphenol A-bis(diphenyl phosphate) monomer 84-89%, Bisphenol A-bis(diphenyl phosphate) dimer 10-13%, The mass ratio of the bisphenol A-bis(diphenyl phosphate) monomer to the bisphenol A-bis(diphenyl phosphate) dimer is (6~9):1; Preferably, the solid bisphenol A-bis(diphenyl phosphate) further comprises the following components in parts by weight: Bisphenol A-bis(diphenyl phosphate) trimer 0.6~2.0%, Triphenyl phosphate 0.4~0.5%; Preferably, the solid bisphenol A-bis(diphenyl phosphate) comprises the following components in parts by weight: Bisphenol A-bis(diphenyl phosphate) monomer 85-88%, Bisphenol A-bis(diphenyl phosphate) dimer 10-12%, Bisphenol A-bis(diphenyl phosphate) trimer 1.1~1.5%, Triphenyl phosphate 0.45~0.5%; Preferably, the mass ratio of the bisphenol A-bis(diphenyl phosphate) monomer to the bisphenol A-bis(diphenyl phosphate) dimer is (6.7~8.7):

1.

10. The application of solid bisphenol A-bis(diphenyl phosphate) prepared by the preparation method according to any one of claims 1 to 7 or solid bisphenol A-bis(diphenyl phosphate) according to any one of claims 8 to 9 in modified flame retardant materials.

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