2,2',3,3',5,5'-hexamethyl-diphenyl-4,4'-diol-bis(trimellitic acid anhydride) powder

Abstract

The present invention provides a powder of 2,2',3,3',5,5'-hexamethyl-biphenyl-4,4'-diol-bis(trimellitic anhydride) having good handling properties and a method for producing the same. As a solution, a powder of 2,2',3,3',5,5'-hexamethyl-biphenyl-4,4'-diol-bis(trimellitic anhydride) having an average particle diameter of 10 to 40 μm is provided.

Description

Technical Field

[0001] This invention relates to 2,2',3,3',5,5'-hexamethyl-biphenyl-4,4'-diol-bis(triphenylamine) powder. Background Technology

[0002] Polyimide not only possesses excellent heat resistance but also exhibits chemical resistance, radiation resistance, electrical insulation, and superior mechanical properties. Therefore, it is widely used in various electronic devices, including substrates for flexible printed circuits (FPCs), substrates for tape-automated bonding (TAB), protective films for semiconductor components, and interlayer insulating films for integrated circuits. In addition to these properties, polyimide has gained increasing importance in recent years due to its simple manufacturing methods, extremely high film purity, and ease of property modification using various available monomers.

[0003] The compound 2,2',3,3',5,5'-hexamethyl-biphenyl-4,4'-diol-bis(triphenylamine anhydride) represented by the following formula (A) (hereinafter sometimes referred to as "compound A") is a useful raw material for polyesterimide resins that possess a high glass transition temperature, a low coefficient of linear thermal expansion equivalent to that of metal foil, extremely low water absorption, high elastic modulus, sufficient toughness, and sufficient adhesion to metal foil (e.g., Patent Documents 1 and 2).

[0004] [Chemistry 1]

[0005]

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2014-001394

[0008] Patent Document 2: International Publication No. 2014 / 046180 Summary of the Invention

[0009] Patent documents 1 and 2 describe a powder of compound A, which is obtained by filtering and drying a slurry containing precipitate. However, as described in Comparative Example 1 below, the filtration operation of the powder is very time-consuming, and the filtered material is a paste containing a large amount of organic solvent, making it difficult to remove from the filtration device and transfer. Therefore, in addition to poor processability, it also requires a lot of time and energy to dry, making it unsuitable for industrial manufacturing.

[0010] The present invention is based on the above-described situation, and its objective is to provide a powder of compound A with good processability and a method for manufacturing the same.

[0011] In order to solve the above-mentioned problems, the inventors conducted in-depth research and found that, compared with the previous powders, the filterability of 2,2',3,3',5,5'-hexamethyl-biphenyl-4,4”-diol-bis(triphenyl benzoic anhydride) powder with a specific particle size range is improved, and the amount of organic solvent contained in the filtered powder is significantly reduced, thus completing the present invention.

[0012] The present invention is as follows.

[0013] 1. A powder of 2,2',3,3',5,5'-hexamethyl-biphenyl-4,4'-diol-bis(triphenylamine), characterized by being represented by the following formula (A), and having an average particle size of 10 μm to 40 μm.

[0014] [Chemistry 2]

[0015]

[0016] 2. The powder according to 1, characterized in that the following variation coefficient is 0.01 to 0.25.

[0017] [Variable coefficient]: The value obtained by dividing the standard deviation of the particle size distribution of the volume reference obtained by the wet laser diffraction particle size distribution measuring device by the average particle size of the powder.

[0018] The powder of the present invention can be easily filtered from a slurry containing the powder, and the filtration operation can be significantly shortened. Furthermore, the filtered material has a low organic solvent content and good processability. In addition, compared with the past, the drying time and energy required can be reduced. Therefore, compound A is suitable for industrial manufacturing and can improve production efficiency. Attached Figure Description

[0019] Figure 1 A graph illustrating the correlation between the product concentration (wt%) at 50°C and the nucleation time (minutes) in the "Confirmation of the Control Range of Product Concentration" of the embodiment and the "Control Range of Product Concentration" below.

[0020] Figure 2 A graph illustrating the correlation between product concentration (wt%) at 30°C and nucleation time (minutes) in the "Confirmation of the Control Range of Product Concentration" of the embodiment.

[0021] Figure 3 A graph illustrating the correlation between product concentration (wt%) and nucleation time (minutes) at 80°C in the "Confirmation of the Control Range of Product Concentration" of the embodiment.

[0022] Figure 4Microscopic images of the powder of the present invention obtained in Example 1 (top: 100x magnification, bottom: 1000x magnification).

[0023] Figure 5 Microscopic photographs (1000x magnification) of powder samples I, II, and III used in the "Filterability Evaluation of Powder of Compound A" in the examples. Detailed Implementation

[0024] The present invention will now be described in detail.

[0025] <Average Particle Size>

[0026] The 2,2',3,3',5,5'-hexamethyl-biphenyl-4,4'-diol-bis(triphenyltrihydric anhydride) powder of the present invention is characterized in that its average particle size is in the range of 10 μm to 40 μm.

[0027] In this invention, "average particle size" refers to the average particle size measured using a wet laser diffraction particle size distribution measuring device and calculated in a volume-based particle size distribution.

[0028] The average particle size of the powder of the present invention is preferably in the range of 10 μm to 35 μm, more preferably in the range of 10 μm to 30 μm, and particularly preferably in the range of 15 μm to 30 μm.

[0029] <Variable Coefficient>

[0030] The preferred variation coefficient of the powder in this invention is in the range of 0.01 to 0.25.

[0031] In this invention, the "variation coefficient" refers to the value obtained by dividing the standard deviation of the particle size distribution of the volume reference obtained by the wet laser diffraction particle size distribution measuring device by the average particle size of the powder.

[0032] The coefficient of variation of the powder of the present invention is preferably in the range of 0.01 to 0.2, more preferably in the range of 0.01 to 0.15, even more preferably in the range of 0.01 to 0.1, and particularly preferably in the range of 0.01 to 0.05.

[0033] <Method for manufacturing the powder of the present invention>

[0034] (reaction)

[0035] When compound a, represented by formula (a) in the following reaction formula, which serves as a raw material for compound A, is mixed with acetic anhydride, which is both a reaction matrix and a solvent, and a solvent used as needed, a rapid dehydration reaction of compound a occurs to generate compound A. The powder of the present invention can be manufactured by controlling the concentration of compound A in the liquid phase of the reaction solution (hereinafter referred to as "product concentration") while carrying out the dehydration reaction of compound a.

[0036] [Chemistry 3]

[0037]

[0038] The compound a represented by the above formula (a) as a starting material for compound A is 4-({4-[4-(3,4-dicarboxyphenylcarbonyloxy)-2,3,5-trimethylphenyl]-2,3,6-trimethylphenyl]oxycarbonyl}benzene-1,2-dicarboxylic acid, and the method for manufacturing this compound is described in prior art literature (International Publication No. 2020 / 080157), and can be synthesized by this method.

[0039] In order to manufacture the powder of the present invention, the purity of the raw materials, measured by gel permeation chromatography (GPC) as an area percentage, is not particularly limited, but is preferably 90% or more, more preferably 92% or more, further preferably 94% or more, and particularly preferably 95% or more.

[0040] In the method for producing compound A shown in the above reaction formula, a reaction catalyst may not be used; however, since the reaction proceeds rapidly when a reaction catalyst is used, it is preferred to use one. As the reaction catalyst, a basic catalyst or an acidic catalyst may be used; specifically, pyridine or pyridine hydrochloride may be used, for example. The amount of catalyst used is preferably 0.1% by weight or more relative to the weight of acetic anhydride, which is both the reaction matrix and solvent.

[0041] There are no particular limitations on the mixing method for the reaction catalyst. For example, it can be pre-mixed into the solvent before starting the above-mentioned dehydration reaction, or it can be added during the process of manufacturing the powder of the present invention through the above-mentioned dehydration reaction. In addition, the total amount of reaction catalyst used can be mixed at once, or it can be mixed in batches.

[0042] In the method for producing compound A as shown in the above reaction formula, acetic anhydride, used as both a reaction matrix and a solvent, is preferably used in an amount of 1 to 20 times the weight of the raw material compound a, more preferably in an amount of 1 to 15 times the weight, and even more preferably in an amount of 1 to 10 times the weight. Using an amount of acetic anhydride exceeding 20 times the weight of the raw material compound a is not preferred from a production efficiency perspective.

[0043] When reacting to produce the powder of the present invention, the crystals of compound A are first present in the reaction solution. This method is not limited; for example, the crystals of compound A can be mixed before the reaction to ensure their presence, or the concentration of the product can be increased by reacting a portion of compound a, which is a raw material, thereby causing crystals to precipitate and be present in the reaction solution.

[0044] The mixed crystals are not limited; powders of conventionally known compound A can be used, or powders of the present invention obtained by using powders of conventionally known compound A in order to remanufacture the powders of the present invention can be used. Furthermore, crystals whose coefficient of variation is adjusted by sieving or the like can also be used. In this case, to manufacture powders of compound A of the present invention with a small coefficient of variation, it is preferable to use powders with a small coefficient of variation.

[0045] (Control range of product concentration)

[0046] The reaction to generate compound A through the dehydration of compound a is carried out by controlling the concentration of the product within a range that is a lower limit relative to the solubility of compound A in the reaction solvent and an upper limit relative to the supersolubility of compound A in the reaction solvent. When the concentration of compound A is below the lower limit of the above-mentioned control range, a portion of the crystals of compound A contained in the reaction solution will dissolve, so it is preferable to control this state as much as possible. However, even if this state occurs, the reaction can continue while controlling the concentration of compound A within the above-mentioned control range to produce the powder of the present invention.

[0047] For example, when only acetic anhydride is used as the reaction solvent, the solubility of compound A is 0.02 wt% at 30°C, 0.05 wt% at 50°C, 0.14 wt% at 75°C, 0.18 wt% at 80°C, and 0.40 wt% at 100°C.

[0048] Supersolubility, also known as supersaturation, refers to the concentration of a dissolved solute that, according to kinetics, maintains a supersaturated state within a specific temperature and time range until nucleation occurs. Supersolubility is affected by factors such as stirring intensity, impurities, and crystallization rate, and therefore cannot be precisely defined; it is usually determined experimentally.

[0049] The oversolubility of compound A in the reaction solvent of this invention can be determined experimentally at the reaction temperature by experimentally determining the relationship between the product concentration calculated from the amount of compound a mixed and the time required from the start of mixing compound a until nucleation (hereinafter referred to as "nucleation time").

[0050] Regarding the upper limit of the product concentration controlled for manufacturing the powder of the present invention, specific examples can be given for illustration. For example, at 50°C, when only acetic anhydride is used as the solvent, the relationship between product concentration and nucleation time was experimentally determined, and the nucleation time was 5 minutes for a product concentration of 1.4 wt%, 15 minutes for 0.8 wt%, 35 minutes for 0.5 wt%, and 75 minutes for 0.3 wt%. From these values, it can be seen that... Figure 1 As shown, a curve (oversolubility curve) is displayed to show the correlation between product concentration (wt%) and nucleation time (min), with the product concentration controlled as the upper limit of this curve.

[0051] If the reaction exceeds this upper limit, the compound A generated in the reaction will nucleate, resulting in a finer powder, thus making it impossible to obtain the powder of the present invention.

[0052] That is, when the reaction solvent is only acetic anhydride and the reaction is carried out at 50°C, the lower limit of the control range of the product concentration is the solubility at this time, i.e., 0.05% by weight, and the upper limit is the supersolubility curve obtained as described above.

[0053] The solvent is not limited to acetic anhydride; other solvents that will not affect the reaction can be used in combination.

[0054] Examples of solvents that can be used together include ether solvents such as tetrahydrofuran, ketone solvents such as acetone, aromatic hydrocarbon solvents such as toluene, and aliphatic hydrocarbon solvents such as hexane.

[0055] At this point, in a mixed solvent containing a solvent that does not affect the reaction, the solubility and supersolubility of compound A are confirmed. The reaction can be carried out while controlling the product concentration within this range, as described above. Therefore, the powder of compound A of the present invention can be produced in the same manner. There is no limitation on the amount of solvent that does not affect the reaction; however, using too much is not preferable from a production efficiency perspective. Therefore, it is preferable to use less than 10 times the weight of the raw material compound a.

[0056] Regarding the reaction temperature range, when only acetic anhydride is used as the reaction solvent, the reaction is carried out in the range of 10–100°C, preferably in the range of 20–90°C, and particularly preferably in the range of 30–80°C. When using a solvent that will not affect the reaction, the boiling point of the solvent is taken into consideration, and the reaction is carried out within a temperature range that will not cause boiling. The temperature at which the reaction is carried out affects the lower limit of the solubility and the upper limit of the supersolubility within the control range of the product concentration; therefore, by confirming this effect in advance, the reaction can be carried out at a constant temperature or with varying temperatures. It is preferable to carry out the reaction at a constant temperature.

[0057] (Methods for controlling the concentration of products)

[0058] The control of the above-mentioned "product concentration" can be implemented by mixing compound a, which is used as a raw material, into the reaction solution while confirming the product concentration.

[0059] As a method to confirm the concentration of the product, for example, one could sample the liquid phase of the reaction solution and quantify the concentration of compound A by gel permeation chromatography or liquid chromatography.

[0060] There are no particular limitations on the mixing method of compound a, which is used as a raw material. For example, methods such as mixing the solid of compound a with the reaction liquid, or dispersing or dissolving the solid of compound a, which is used as a raw material, in acetic anhydride or a solvent that will not adversely affect the reaction and mixing it with the reaction liquid.

[0061] When manufacturing the powder of the present invention on an industrial scale, as a method for controlling the above-mentioned "product concentration" and mixing compound a, which is a raw material, into the reaction liquid, a powder metering device can be cited as an example. As a method for mixing the dispersion or solution of compound A, for example, mixing can be performed using a metering device from a tank of pre-prepared dispersion or solution.

[0062] As shown in Comparative Example 2 described later, when the dehydration reaction is carried out without controlling the "product concentration", powder with a small average particle size can be obtained.

[0063] (filter)

[0064] The reaction solution produced according to the above-described method for determining the "product concentration" contains the powder of the present invention, which can be separated by a filtration process. Conventional powders of compound A, as described in Comparative Example 1 below, are pastes containing a large amount of solvent even when the filtration process is lengthy. In contrast, the powder of the present invention exhibits superior filterability in this filtration process, allowing filtration to be completed in a shorter time compared to conventional powders. Furthermore, it contains less solvent after filtration, resulting in excellent processability.

[0065] (dry)

[0066] The drying of the powder of the present invention separated by filtration can be carried out at a temperature range of 40 to 120°C, or at atmospheric pressure or at reduced pressure, preferably at reduced pressure.

[0067] The powder of the present invention has less solvent adhering to it compared with conventional powders, thus shortening the drying time and allowing the process to be completed with less energy.

[0068] In addition, the above-mentioned processes such as reaction, filtration, and drying are preferably carried out in an inert gas environment (e.g., nitrogen or argon).

[0069] Example

[0070] The present invention will be described in more detail below through embodiments, but the present invention is not limited to these embodiments.

[0071] The analytical method of this invention is as follows.

[0072] 1. Determination of average particle size

[0073] Apparatus: Shimadzu SALD-2200 (Laser Diffraction Particle Size Distribution Measurement Apparatus) manufactured by Shimadzu Corporation

[0074] Measurement range: 1000~0.030μm

[0075] Dispersing solvent: distilled water + neutral detergent

[0076] Dispersion method: Ultrasonic dispersion

[0077] 2. Microscopic photographs of powders

[0078] Machine: KEYENCE VHX-1000

[0079] 3. Methods for confirming the concentration of the product

[0080] The concentrations of the products in the reaction solution in the examples were confirmed by the following analytical methods.

[0081] [Analysis Methods]

[0082] Equipment: TOSOH HLC-8320 GPC high-speed GPC device

[0083] Columns: 1 TSK gel guardcolumn HXL-L, 2 TSK gel G2000HXL, 1 TSK gel G3000HXL, 1 TSK gel G400

[0084] Flow rate: Pump Sam. 1.0 ml / min, 1 / 3 of Ref. Sam.

[0085] Mobile phase: Tetrahydrofuran

[0086] Column temperature: fixed at 40℃

[0087] Detector: Differential refractometer (RI) The RI detector is an instrument that detects the difference in refractive index between the solution on the sample side and the eluent on the reference side. The refractive index of the solution is correlated with the weight concentration of the solution.

[0088] Sample concentration: 0–100 mg / 50 ml (tetrahydrofuran solution)

[0089] Injection volume: 100μL

[0090] Calibration method for compound A: Calculated using a calibration curve prepared by GPC. When determining the concentration of the product of compound A, a sample solution is quickly obtained using a syringe heated to the same temperature as the solution to be measured. This sample is then quickly passed through a similarly heated filter (Econofilter, PTFE 13mm 0.45μm, Agilent Technologies) to remove precipitated compound A and unwanted substances.

[0091] The powder of compound A obtained by conventional manufacturing methods will be described below.

[0092] <Comparative Example 1: Powder of Compound A based on the manufacturing method described in Patent Document 2 above>

[0093] The manufacturing method described in "Synthesis Example 1" of Patent Document 2 above was expanded to an experimental scale of 8.5 times for verification testing, and powder of compound A was obtained through a "refining" process. In the "refining" process, when the powder was filtered by suction filtration using a suction device, after about 1 hour of depressurization, no liquid was discharged, and the filter material on the funnel was a paste containing a large amount of solvent.

[0094] The filter material was dried, and the weight change before and after drying confirmed that the filter material contained 49% by weight of solvent.

[0095] The average particle size of the dried powder was 4.8 μm, with a variation coefficient of 0.08.

[0096] The results of Comparative Example 1 show that the average particle size of the powder of Compound A obtained by conventional manufacturing methods is as small as 4.8 μm, the filtration operation requires a long time, and the filtrate contains a large amount of organic solvent.

[0097] Next, the method for manufacturing compound a will be explained.

[0098] <Reference Synthesis Example 1>

[0099] Add 242.5 g of trimellitic anhydride chloride and 714.3 g of tetrahydrofuran (THF) to a four-necked flask equipped with a thermometer, stirrer, and cooling tube, allowing the trimellitic anhydride chloride to dissolve completely while cooling. Add 135.3 g of 2,2',3,3',5,5'-hexamethyl-biphenyl-4,4'-diol, 908.5 g of THF, and 197.8 g of pyridine to an Erlenmeyer flask, dissolving at room temperature. Intermittently mix the solution in the four-necked flask, which has been cooled to 0–5°C, for 2 hours. Then, stir continuously for 2 hours, heat for 1 hour to reach 65°C, and stir continuously for 4 hours.

[0100] After the reaction was complete, the mixture was cooled to 40°C, mixed with 117.6 g of distilled water, and stirred continuously for 19 hours. Compound a was separated by centrifugation and filtration, washed with acetone, and 697.2 g of compound a containing solvent (THF, acetone) or pyridine hydrochloride was obtained. The powder was dried at 70°C for 3 hours under reduced pressure of approximately 1.5 kPa to obtain 441.3 g of compound a containing 34% by weight pyridine hydrochloride.

[0101] <Reference Synthesis Example 2>

[0102] Add 242.7 g of trimellitic anhydride chloride and 714.3 g of THF to a four-necked flask equipped with a thermometer, stirrer, and cooling tube, allowing the trimellitic anhydride chloride to dissolve completely while cooling. Add 135.3 g of 2,2',3,3',5,5'-hexamethyl-biphenyl-4,4'-diol, 909.6 g of THF, and 197.8 g of pyridine to an Erlenmeyer flask, dissolving at room temperature. Intermittently mix the solution in the four-necked flask, which has been cooled to 0–5°C, for 2 hours. Then, stir continuously for 2 hours, heat for 1 hour to reach 65°C, and stir continuously for 4 hours.

[0103] After the reaction was completed, the mixture was cooled to 40°C, mixed with 118.1 g of distilled water, and stirred continuously for 14 hours. The resulting compound a was separated by centrifugation and filtration, washed with acetone, and 892.7 g of compound a containing 42 wt% THF, acetone, and water, and 21 wt% pyridine hydrochloride was obtained.

[0104] <Reference Synthesis Example 3: Preparation of Compound a based on the ring-opening reaction of compound A>

[0105] 102.2 g of compound A, 306.5 g of THF, 153.4 g of water, and 1.1 g of 85% phosphoric acid, obtained by the same method as in Comparative Example 1, were added to a four-necked flask equipped with a thermometer, stirrer, and cooling tube. The mixture was heated to 65°C and stirred continuously for 3 hours. The temperature was then lowered to 60°C, and 0.1 g of seed crystals of compound a obtained in Reference Synthesis Example 1 were mixed in. 300 g of water was then added dropwise over 20 minutes, and the temperature was lowered to 15°C at a rate of 10°C / hour. The slurry was filtered by suction, and the resulting powder was dried under reduced pressure at 80°C and 2 kPa to obtain 73.9 g of compound a.

[0106] <Reference Synthesis Example 4>

[0107] Add 291.6 g of trimellitic anhydride chloride and 859.1 g of THF to a four-necked flask equipped with a thermometer, stirrer, and cooling tube, allowing the trimellitic anhydride chloride to dissolve completely while cooling. Add 162.7 g (0.602 mol) of 2,2',3,3',5,5'-hexamethyl-biphenyl-4,4'-diol, 1093.3 g of THF, and 238.1 g of pyridine to an Erlenmeyer flask, dissolving at room temperature. Intermittently mix the solution in the four-necked flask, which has been cooled to 0–5°C, for 2 hours. Then stir continuously for 2 hours. Then heat for 1 hour to bring the temperature of the liquid in the flask to 65°C, and stir continuously for 3.5 hours.

[0108] After the reaction was completed, the mixture was cooled to 25°C, mixed with 118.1 g of distilled water, heated to 40°C, and stirred continuously for 9 hours. Then, the generated compound a was separated by centrifugation and filtration, washed with acetone, and 875.1 g of compound a containing 34 wt% THF, acetone, and water, and 24 wt% pyridine hydrochloride was obtained.

[0109] (Confirmation of the control range for product concentration)

[0110] (1) Solubility (lower limit of the control range for product concentration)

[0111] The solubility of compound A relative to acetic anhydride was determined at the target temperature.

[0112] The results showed that the content was 0.02 wt% at 30°C, 0.05 wt% at 50°C, 0.14 wt% at 75°C, 0.18 wt% at 80°C, and 0.40 wt% at 100°C.

[0113] (2) Excess solubility (the upper limit of the control range of product concentration)

[0114] Add 30 g of acetic anhydride to a flask with a stir bar and heat to the target temperature (30°C, 50°C, 80°C). Change the weight by measuring the concentration, and mix 0.45–0.09 g of compound a prepared in Reference Synthesis Example 3 above into the flask. Before mixing compound a, pyridine at 37% by weight relative to compound a is pre-mixed into the acetic anhydride. Starting from the mixing of compound a, observe the concentration of the product of compound A while timing with a stopwatch. Analyze the product concentration using the above method when the solution begins to turn cloudy by visual inspection, or when it is difficult to observe visually. The time of concentration change is taken as the nucleation time, and the nucleation time of each product concentration is measured. Plot the product concentration (wt%) versus nucleation time (minutes) to create a solubility curve (…). Figures 1-3 ).

[0115] Figures 1-3In the diagram, the markers represent measured values, and the solid line represents the predicted supersolubility curve.

[0116] <Example 1>

[0117] 150.0 g of acetic anhydride was added to a four-necked flask equipped with a thermometer, stirrer, and cooling tube. 1.0 g of powder of compound A obtained in Comparative Example 1 (average particle size 4.8 μm, coefficient of variation 0.08) was added as seed crystals to suspend the seed crystals. Meanwhile, a mixture of 25.8 g of compound a prepared in Reference Synthesis Example 3 and 8.3 g of pyridine as a reaction catalyst was prepared beforehand. The temperature of the suspension in the flask was maintained at 30°C, and the prepared mixture was mixed while stirring. As a mixing method, 0.3 g was mixed every 30 minutes initially, and the mixing time intervals were gradually shortened to control the overall concentration so that it did not exceed the supersolubility curve obtained by the above method (when the product concentration was below 0.3 wt%, the product concentration could be controlled without exceeding the supersolubility curve by mixing the prepared mixture with an amount of compound a that increased the product concentration by 0.15 to 0.2 wt%).

[0118] After the reaction, 29.5g of the solvent-containing powder was separated from the slurry by suction filtration, and 23.6g of the target compound A powder was obtained by drying.

[0119] The weight change before and after drying confirmed that the filtered powder contained 20% by weight of solvent.

[0120] The average particle size of the obtained powder was 17.1 μm, with a coefficient of variation of 0.02. Furthermore, microscopic observation revealed that the powder exhibited a scaly appearance.

[0121] Figure 4 The image shows a microscope photograph of the obtained powder. The top image is magnified 100 times, and the bottom image is magnified 1000 times.

[0122] <Example 2>

[0123] Add 80.0 g of acetic anhydride to a four-necked flask equipped with a thermometer, stirrer, and cooling tube. Maintain the liquid temperature in the flask at 50°C, and mix 1.2 g of compound a prepared in Reference Synthesis Example 1 above while stirring. After about 1 hour and the precipitation of compound A crystals, mix 22.4 g of the same compound a. As a mixing method, first mix 0.4 g every 15 minutes, and gradually shorten the mixing time intervals to control the overall concentration of the product so as not to exceed the supersolubility curve obtained by the above method (when the product concentration is below 0.3 wt%, mixing an amount of compound a that increases the product concentration by 0.3 to 0.4 wt% can control the product concentration without exceeding the supersolubility curve). Then, raise the temperature to 90 to 95°C, stir continuously for 2 hours, and then cool to 30°C.

[0124] After the reaction of all compounds a was completed, 12.0 g of the slurry containing solvent was separated by suction filtration, and 11.2 g of the target compound A powder was obtained by drying.

[0125] The weight change before and after drying confirmed that the filtered powder contained 7% by weight of solvent.

[0126] The average particle size of the obtained powder was 17.1 μm, with a coefficient of variation of 0.02. Furthermore, microscopic observation revealed that the powder exhibited a scaly appearance.

[0127] <Example 3>

[0128] 1000.8 g of acetic anhydride was added to a four-necked flask equipped with a thermometer, stirrer, and cooling tube. The liquid temperature in the flask was maintained at 50°C, and 24.0 g of compound a prepared in Reference Synthesis Example 2 was mixed while stirring. After approximately 1 hour, and after crystals of compound A precipitated, 483.0 g of the same compound a was mixed. As a mixing method, 9.4 g was mixed every 15 minutes, with the mixing intervals gradually shortened to control the overall concentration so that it did not exceed the supersolubility curve obtained by the above method (when the product concentration is below 0.3 wt%, mixing an amount of compound a that increases the product concentration by 0.3–0.4 wt% can control the product concentration without exceeding the supersolubility curve). Then, the temperature was raised to 90–95°C, and after continuous stirring for 2 hours, it was cooled to 30°C.

[0129] After the reaction of all compounds a was completed, the slurry containing solvent was separated by centrifugation and filtration, yielding 270.0 g of powder.

[0130] A portion of the separated solvent-containing powder was removed and dried. The weight change before and after drying confirmed that the filtered powder contained 40% by weight of solvent.

[0131] The average particle size of the dried powder was 10.8 μm, with a variation coefficient of 0.03.

[0132] <Example 4>

[0133] Add 20.1 g of acetic anhydride to a four-necked flask equipped with a thermometer, stirrer, and cooling tube. Maintain the temperature inside the flask at 50°C and mix 0.5 g of compound a prepared in Reference Synthesis Example 2 above. After about 1 hour and the precipitation of crystals of compound A, mix 202.2 g of the same compound a and 379.4 g of acetic anhydride. As for the mixing method, for compound a, first mix 0.1 g of compound a every 30 minutes, and gradually shorten the mixing time interval and increase the amount mixed, controlling the overall concentration so that the product concentration does not exceed the supersolubility curve obtained by the above method (when the product concentration is less than 0.3% by weight, by mixing compound a with a product concentration of 0.3 to 0.4% by weight, the product concentration can be controlled without exceeding the supersolubility curve). On the other hand, regarding acetic anhydride, at the point when 0.8g of 202.2g of compound a is mixed, 30g of acetic anhydride is first mixed, and then acetic anhydride is mixed in such a way that the proportion of compound a in the flask does not exceed 36% until the total amount of acetic anhydride reaches 399.5g.

[0134] After the reaction of all compounds a and acetic anhydride was completed, 71.8 g of powder containing solvent was separated from the slurry by suction filtration, and 61.9 g of target compound A powder was obtained by drying.

[0135] The weight change before and after drying confirmed that the filtered powder contained 14% by weight of solvent.

[0136] The average particle size of the obtained powder was 20.6 μm, and the coefficient of variation was 0.02.

[0137] <Example 5>

[0138] The powder obtained in Example 4 was used as a seed crystal to further manufacture powder with a large average particle size.

[0139] 40.6 g of acetic anhydride, 0.1 g of pyridine, and 0.5 g of the undried powder of compound A prepared in Example 4 were added to a four-necked flask equipped with a thermometer, stirrer, and cooling tube. The temperature of the suspension in the flask was maintained at 50°C, and 13.3 g of compound a prepared in Reference Synthesis Example 3 was mixed. As a mixing method, 0.2 g was mixed every 10 minutes, and the mixing time intervals were gradually shortened to control the overall concentration of the product from not exceeding the supersolubility curve obtained by the above method (when the product concentration is below 0.3% by weight, mixing an amount of compound a that increases the product concentration by 0.3 to 0.4% by weight can control the product concentration without exceeding the supersolubility curve). In addition, during this mixing process, at the time point when 6.7 g of the 13.3 g of compound a was mixed, 40 g of acetic anhydride was mixed as a solvent and 0.10 g of pyridine was mixed as a catalyst.

[0140] After the reaction of all compounds a was completed, 12.9 g of the slurry containing solvent was separated by suction filtration, and 12.5 g of the target compound A powder was obtained by drying.

[0141] The weight change before and after drying confirmed that the filtered powder contained 3% by weight of solvent.

[0142] The average particle size of the obtained powder was 23.2 μm, and the coefficient of variation was 0.02.

[0143] <Example 6>

[0144] Add 100.5g of acetic anhydride to a four-necked flask equipped with a thermometer, stirrer, and cooling tube.

[0145] The liquid temperature in the flask was maintained at 80°C, and 2.1 g of compound a prepared in Reference Synthesis Example 2 was mixed while stirring. After about 2 hours, crystals precipitated, and then 51.0 g of the same compound a was mixed. As a mixing method, 0.7 g was mixed every 30 minutes, and the mixing time intervals were gradually shortened to control the overall concentration of the product not exceeding the supersolubility curve obtained by the above method (when the product concentration is below 0.45 wt%, mixing an amount of compound a that increases the product concentration by 0.1 to 0.2 wt% can control the product concentration without exceeding the supersolubility curve). Then, the temperature was raised to 90 to 95°C, and after stirring for 2 hours, it was cooled to 30°C. The slurry after the reaction was completed was filtered by suction to separate 17.7 g of powder containing solvent, and 15.6 g of target compound A powder was obtained by drying.

[0146] The weight change before and after drying confirmed that the filtered powder contained 12% by weight of solvent.

[0147] The average particle size of the dried powder was 13.1 μm, with a variation coefficient of 0.04.

[0148] <Comparative Example 2: Manufacturing powder of compound A by a manufacturing method that does not control the "product concentration">

[0149] 872.6 g of compound a and 1967.3 g of acetic anhydride, prepared in Reference Synthesis Example 4 above, were added to a four-necked flask equipped with a thermometer, stirrer, and cooling tube. The liquid in the flask was then heated to 100°C and stirred continuously for 2 hours, followed by cooling to 30°C. To recover the powder, the slurry after the reaction was completed was centrifuged and filtered by rotating the filter for 20 minutes. Although the liquid discharge became invisible, the filtrate was a paste containing a large amount of solvent.

[0150] A portion of the filter material was removed and dried. The change in weight before and after drying confirmed that the filter material contained 61% by weight of solvent.

[0151] The average particle size of the powder in the obtained filter media was 2.1 μm, with a variation coefficient of 0.23.

[0152] The results of Comparative Example 2 confirm that if the reaction is carried out without controlling the "product concentration" of compound A in the reaction system, a small powder with an average particle size of 2.1 μm is obtained. Similar to the powder of compound A obtained by conventional manufacturing methods, except that the filtration operation takes time, the precipitate obtained by filtration contains a large amount of organic solvent.

[0153] <The solvent content ratio for producing the filtered powder of compound A>

[0154] Regarding Compound A of Examples 1-6 and Comparative Examples 1 and 2 above, the average particle size (μm) of the powder, the proportion of solvent contained in the filtered powder (wt%), and the state of the filtered material after the filtration operation are summarized in Table 1 below.

[0155] [Table 1]

[0156]

[0157] As shown in Table 1, it can be seen that the powders of Examples 1 to 6 of the present invention, compared with the powder of Comparative Example 1 obtained by conventionally known methods and the powder of Comparative Example 2 obtained by methods without controlling the concentration of the product, have a lower solvent content and the state of the filter material after filtration is powder. Therefore, it can be seen that the processability during removal or transfer after filtration is good.

[0158] Since the filtered material after the filtration operation of the powder of the present invention is in powder form, it is suitable for industrial manufacturing. It is also easy to process when drying to remove the solvent attached to the powder, which can reduce the energy or time required for drying and can be manufactured efficiently.

[0159] In contrast, the filtrates from Compound A (Comparative Example 1), obtained by conventionally known methods but not as a specific example of this invention, and Compound A (Comparative Example 2), obtained by methods without controlling the concentration of the product, are paste-like substances containing a large amount of solvent, making handling difficult when removing or transferring them after filtration. Under these conditions, industrial manufacturing of Compound A is difficult due to the difficulty in filtering the powder, or the inherent difficulty in removing it from the filter, and the difficulty in transferring it, making it unsuitable for industrial manufacturing. Furthermore, it is known that drying to remove solvent adhering to the powder results in poor processability and the presence of a large amount of solvent, thus requiring a large amount of energy or time for drying, making it inefficient in manufacturing.

[0160] The results above show that the powder of the present invention can be effectively manufactured industrially and is very useful.

[0161] <Evaluation of the filterability of compound A powder>

[0162] To clarify the causal relationship between the average particle size of compound A and its filterability, the filterability was evaluated using the following guidelines.

[0163] (Evaluation Method)

[0164] The filterability of powder samples I (powder of Example 1), II, and III (powders with different average particle sizes obtained by the same method as Comparative Example 1) of compound A with average particle size shown in Table 2 below was evaluated by the following machine, operation, and filtration time (“filtration time”).

[0165] (device)

[0166] Prepare a filtration device based on a Kiriyama funnel (filter paper No. 5C) with a pressure reducing device (water flow aspirator), a pressure regulating valve, and a pressure gauge (PG-100HANDY MANOMETER manufactured by Copal Electrics).

[0167] (operate)

[0168] Mix 10g of powder with 34g of acetic anhydride in a beaker to prepare a slurry.

[0169] First, while depressurizing the pressure using a water-flow aspirator, the prepared slurry is fed into the Kiriyama funnel of the device to form a filter medium of uniform thickness, and the filtrate is recovered. Then, the recovered filtrate is rapidly injected again into the filter medium on the Kiriyama funnel, and the pressure inside the filtration device is controlled at 10 kPa to carry out filtration.

[0170] (Filtering time)

[0171] The filtration time is measured from the moment all the filtrate is poured onto the filter media until the filtrate is drawn out and the pressure begins to rise. This time, measured in seconds, is defined as the "filtration time" by temporarily reducing the pressure by suction and measuring the remaining time until the pressure starts to rise again.

[0172] The physical properties and filtration times (seconds) of the powder samples I, II, and III are summarized in Table 2 below.

[0173] also, Figure 5 The image shows microscope photographs (1000x magnification) of powder samples I, II, and III.

[0174] [Table 2]

[0175]

[0176] It was found that the filtration time required for Sample I of Example 1 of the present invention was reduced by about 2.7 to about 7.2 times compared to Sample II or Sample III of conventionally known powders that are different from the powders of the present invention.

[0177] Furthermore, it was confirmed that the amount of solvent contained in the powders of Examples 1 to 3 of the present invention was significantly reduced after the filtration operation compared with the powders of Comparative Examples 1 and 2. Therefore, in the subsequent drying process, the drying of the powder can be carried out in a short time, and the amount of energy required to evaporate the solvent is significantly reduced.

[0178] Therefore, the powder of the present invention can be implemented in industrial production in a significantly effective manner, and is thus extremely useful.

Claims

1. A 2,2',3,3',5,5'-hexamethyl-biphenyl-4,4'-diol-bis(triphenylamine) powder, characterized in that, It is represented by the following formula (A), and the average particle size is 10μm~40μm, with the following variation coefficient being 0.01~0.

1. [Variable coefficient]: The value obtained by dividing the standard deviation of the particle size distribution of the volume reference, measured by a wet laser diffraction particle size distribution measuring device, by the average particle size of the powder. [Chemistry 1] 。 2. The powder according to claim 1, characterized in that, The average particle size is in the range of 10 μm to 35 μm.

3. The powder according to claim 1, characterized in that, The average particle size is in the range of 10 μm to 30 μm.

4. The powder according to claim 1, characterized in that, The average particle size is in the range of 15μm to 30μm.

5. The powder according to claim 1, characterized in that, The variation coefficient is in the range of 0.01 to 0.05.

Images