A preparation device of modified organic pigment nanocrystals for photoresist

Abstract

The application discloses a preparation device for modified organic pigment nanocrystals of photoresist, which comprises a conveying pipeline, a circulating tank, a product tank, a first high-pressure pump, a third high-pressure pump, a CO2 pipeline and a continuous synthesis device, the continuous synthesis device comprises N recovery tanks and back pressure valves, the back pressure valves are connected with the N recovery tanks respectively, a smoothly movable piston is arranged in each recovery tank, a first heating device is arranged on the conveying pipeline, the conveying pipeline is communicated with the circulating tank through the first high-pressure pump, the first high-pressure pump is used for pumping the solution of the organic pigment and a good solvent in the circulating tank into the conveying pipeline, the CO2 pipeline is connected with the lower regions in the N recovery tanks respectively, and the recovery tanks are injected with ultrapure water for controlling pressure balance. The application can realize the continuous and stable synthesis of the organic pigment nanocrystals, realizes mass production of the organic pigment nanocrystals, and has the characteristics of controllable nanocrystal size, high dispersibility, low cost, stable effect, good reproducibility and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of semiconductors, and relates to a preparation technology of color photoresist, in particular to a preparation device of modified organic pigment nanocrystals for photoresist. BACKGROUND

[0002] In the field of flat panel display, TFT-LCD (Thin Film Transistor-Liquid Crystal Display) is the mainstream of the market, and CF (Color Filter) is a key device for realizing color display of TFT-LCD, which enables liquid crystal display to realize colorization and determines the display quality of color image of the display. In the process of pursuing high quality and high definition of display effect, innovation and improvement of high-quality CF in terms of material and preparation technology are necessary. The nanocrystallization technology of organic pigment as the main constituent material and the technology of uniformly dispersing the same in color photoresist are the most critical part.

[0003] The quality of color filter mainly depends on the photoresist performance of pigment and its coating process, and the photoresist pigment is one of the most important influencing factors as a colorant. In order to fully exert the coloring power and brightness and obtain good light emission characteristics, the organic pigment particles must be dispersed in the photoresist in a fine, uniform and stable state as much as possible. At present, the main means is to select high light emission efficiency and high quality organic pigment, and to obtain pigment dispersion body-color color paste with fine and stable particle size through grinding and high-efficiency dispersion treatment. The dispersion state and particle size of the pigment determine whether the final coating layer has high transmittance and high contrast.

[0004] Organic pigments are widely used in coatings, printing inks, pigments for color copiers, inkjet printing inks and displays CF, which have become indispensable parts in modern life. Among them, as a representative of continuous pursuit of high performance, the thinning of CF is a typical example. With the high pixelization of digital cameras, the progress and popularization of high-definition display technology of 4K & 8K, the thinning of CF in CCD optical sensor and display unit in display screen has also become a necessary condition for high quality and high performance. The thickness of CF is closely related to the particle size of organic pigment, which is an important component material. The manufacturing technology of organic pigment nanoparticles with controllable particle size at the nanometer level and independent dispersion has been concerned and continuously developed.

[0005] In the synthesis of organic pigment nanocrystals, experiments have shown that it is difficult to obtain organic pigment particles below 200 nm by grinding in a top-down processing method. If the evaporation method in an inert gas is used in a bottom-up processing method, due to the heating conditions accompanying vaporization, it is difficult to apply to organic compounds with poor heat resistance. Therefore, research on gas phase organic pigment nanocrystals is not active, and there are few practical applications from the point of view of large size corresponding equipment & complex and high cost process. Compared with the gas phase method, the reprecipitation method, which is simple to operate, inexpensive, and almost suitable for the manufacture of all organic pigment nanocrystals, is proposed and widely used in related research. Figure 1 The specific experimental operation is as follows: select the best solvent for the organic pigment, dissolve the organic pigment in the solvent to prepare a 0.1-30 mM solution, use a microsyringe to take 50-1000 ul of the organic pigment solution, and inject it into the poor solvent of the organic pigment under high-speed stirring conditions. Adjust the experimental conditions to easily obtain organic pigment nanoparticles with a particle size of 50 nm or less and a relatively narrow particle size distribution (the particle size distribution can be further narrowed by centrifugal separation). For organic pigments that are not soluble in water, the poor solvent is usually ultrapure water, and the good solvent is usually an organic solvent such as acetone, alcohol, or ester that is soluble in water; for organic pigments that are soluble in water, the poor solvent is usually a saturated hydrocarbon such as hexane, cyclohexane, and decalin, and the reprecipitation method is synthesized in a reverse phase. The biggest point of the above reprecipitation method of organic pigment nanoparticles is that after the injection of the organic pigment solution, the good solvent can quickly diffuse and dissolve in the poor solvent, and the organic pigment will quickly precipitate (precipitate) in the poor solvent; by changing various experimental conditions, the size of the nanoparticles can be controlled and adjusted. There are many control factors in the reprecipitation method for controlling the size of organic pigment nanoparticles, such as the state (type, amount, concentration) of the injection solution and the poor solvent, the injection conditions (injection speed, pressure, needle aperture, stirring speed, etc.), and the presence or absence of a surface modifier. Among these factors that affect the size of the nanocrystals, the concentration of the injection solution and the temperature of the poor solvent are the most important.

[0006] In summary, the reprecipitation method can relatively easily obtain organic pigment nanoparticles using the solubility difference between good solvents and poor solvents. However, this method also has limitations, such as the limited solubility of organic pigments in good solvents, the use of large amounts of organic solvents during the process, and the generation of wastewater contaminated with organic solvents, which increases the cost of manufacturing organic pigment nanoparticles due to low yield, recovery of organic solvents, and environmental requirements for wastewater treatment with organic pollution. Figure 2To solve these problems, researchers have used the characteristics of supercritical CO2 to propose and verify the so-called supercritical CO2 anti-solvent method, English abbreviation GAS (Gas Antisolvent) method or SAS (Supercritical Antisolvent) method is also suitable for the synthesis of almost all organic pigment nanoparticles. This method is to dissolve the organic pigment in a suitable organic solvent, and use the feature that the solubility of the target substance in supercritical CO2 is greatly reduced. When the solution containing the organic pigment and the supercritical CO2 fluid are contacted at the nozzle, the nanocrystals of the organic pigment are precipitated, and the size of the target nanoparticles can be controlled. Because supercritical CO2 is miscible with organic solvents, and the rapid expansion and gasification of supercritical CO2 after pressure reduction can increase the supersaturation of organic pigment nanocrystals by more than ten thousand times, this method is more likely to obtain small-sized organic pigment nanoparticles than the previous reprecipitation method. At the same time, CO2 can be recycled, eliminating the need to treat organic contaminated wastewater and reducing the cost of organic solvent recovery. In addition, supercritical CO2 can be mixed with alcohols in large proportions, and we can choose appropriate organic modifier molecules to uniformly disperse in the mixed fluid of supercritical CO2 and alcohol. When the organic pigment-containing organic solution is contacted with supercritical CO2, a layer of organic modifier molecules is precipitated on the surface of the organic pigment nanoparticles. Because it is still in a supercritical fluid state at the moment of contact, the organic modifier molecules will uniformly disperse around the precipitated nanoparticles and adsorb on the particle surface during rapid pressure reduction. Because of its presence, organic pigment nanoparticles are not easy to agglomerate (even if they do, they are easy to disperse again), and crystallization will not continue to grow, so the particle size distribution is relatively narrow. The nanocrystals are precipitated instantaneously during rapid pressure reduction, and quickly pass through the subcritical state that is prone to form surface defects and introduce impurities, making it easy to obtain nanocrystals with high luminescent efficiency.

[0007] Both the reprecipitation method and the supercritical CO2 anti-solvent method can relatively easily obtain organic pigment nanoparticles, and the solubility of supercritical CO2 for organic modifiers and the miscibility of supercritical CO2 with organic solvents in a large proportion make the supercritical CO2 anti-solvent method also suitable for implementing appropriate surface modification of organic pigment nanoparticles to increase the independent dispersibility of nanoparticles. However, both methods can only be implemented in batch mode, and the concentration of the good solution of the organic pigment is very low, and the yield of the nanoparticles is also low, which cannot correspond to the mass production of organic pigment nanoparticles. The reprecipitation method has the problem of treatment of organic contaminated wastewater, and the supercritical CO2 anti-solvent method must solve the problem of safe operation of high-temperature and high-pressure large-capacity equipment if it is to be implemented in mass production. SUMMARY

[0008] The application aims at overcoming the problem that it is difficult to mass-produce organic pigment nanocrystals in the prior art, and provides a preparation device for modified organic pigment nanocrystals for photoresists, which can realize continuous and stable synthesis of organic pigment nanoparticles, improve the yield of nanoparticles, realize mass production of organic pigment nanocrystals, and has the characteristics of controllable nanocrystal size, high dispersibility, low cost, stable effect, good reproducibility and the like.

[0009] The application provides a preparation device for modified organic pigment nanocrystals for photoresists, which comprises a conveying pipeline, a circulating tank, a product tank, a first high-pressure pump, a third high-pressure pump, a CO2 pipeline and a continuous synthesis device, the continuous synthesis device comprises N recovery tanks and back pressure valves arranged in parallel, the back pressure valves are respectively connected with the N recovery tanks, each recovery tank is divided into an upper cabin and a lower cabin, a piston capable of smoothly moving is arranged between the upper cabin and the lower cabin, a first heating device is arranged on the conveying pipeline, the conveying pipeline is communicated with the circulating tank through the first high-pressure pump, the first high-pressure pump is used for pumping the solution of organic pigment and good solvent in the circulating tank into the conveying pipeline, the first heating device is used for heating the solution of organic pigment and good solvent to a subcritical state of the maximum solubility of the organic pigment, the conveying pipeline is respectively connected with the lower cabins in the N recovery tanks, the CO2 pipeline is respectively connected with the lower cabins in the N recovery tanks, the CO2 pipeline is connected with a supercritical CO2 source through the third high-pressure pump, the CO2 pipeline is also connected with a modifier source, the upper cabin in the recovery tank is injected with ultrapure water for controlling pressure balance, and the product tank is arranged at the bottom of the N recovery tanks and used for receiving the dispersion liquid of the organic pigment nanoparticles after surface modification.

[0010] Further, the continuous synthesis device further comprises a circulating tank, the back pressure valves are connected with the circulating tank, the conveying pipeline is connected with the lower cabin in the circulating tank, the upper cabin in the circulating tank is filled with ultrapure water, and the bottom of the circulating tank is connected with the circulating tank. The purpose of injecting ultrapure water is to realize pressure balance in the circulating tank and ensure that the set pressure of the back pressure valve can also be maintained in the circulating tank, so as to realize pressure balance of the whole continuous synthesis device system and ensure that the pressure of the whole system can be stably maintained at the same set pressure during synthesis of the organic pigment nanocrystals.

[0011] Further, the bottom of the circulating tank is provided with a ball valve, and the subcritical fluid of the organic pigment in the circulating tank can be recovered into the circulating tank through the ball valve.

[0012] Further, a filter is arranged at the inlet of the back pressure valve, and the filter is used to prevent the back pressure valve from being easily blocked or the system pressure from being unstable during continuous synthesis of the nanocrystals.

[0013] Further, a second heating device is arranged between the third high-pressure pump and the recovery tank, and is used to ensure that the mixed fluid after the subcritical fluid containing the organic pigment is contacted with the supercritical CO2 is still in a supercritical state.

[0014] Further, a rapid decompression device is arranged between the N recovery tanks and the product tank, and is used to realize decompression of the recovery tank, so that the dispersion liquid of the organic pigment nanoparticles can flow into the product tank quickly.

[0015] Further, a cooling device is arranged on the conveying pipeline, and the temperature and the rapid injection amount of the supersaturated organic pigment subcritical solution can significantly affect the precipitation of the organic pigment nanoparticles and the particle size, and the cooling device can be used to precisely control the suitable precipitation conditions.

[0016] Further, a second high-pressure pump is connected and arranged at the outlet of the first heating device on the conveying pipeline, and is used to guide the stable dispersion liquid of the normal-temperature organic pigment in the good solvent in the circulating tank into the conveying pipeline.

[0017] Based on the above device, the application provides a preparation method of modified organic pigment nanocrystals for photoresist, comprising the following steps:

[0018] S1: adjusting the saturation of the organic pigment in the good solvent, then filtering and placing in the circulating tank for standby;

[0019] S2: guiding the good solvent solution of the standby organic pigment in the circulating tank into the pipeline by the first high-pressure pump for heating, and heating to the subcritical state of the maximum solubility of the organic pigment;

[0020] S3: providing a continuous synthesis device, which comprises N recovery tanks and a back pressure valve, and the N recovery tanks are respectively a No. 1 recovery tank, a No. 2 recovery tank,..., and an N recovery tank; each recovery tank is divided into an upper cabin and a lower cabin, and a piston capable of smoothly moving is arranged between the upper cabin and the lower cabin; the upper cabin of the recovery tank is injected with ultrapure water for pressure balance; the system pressure is set by the back pressure valve; and the pressure of the upper cabin and the lower cabin in the recovery tank is adjusted to the system pressure by the piston.

[0021] The determined modifier and the supercritical CO2 are mixed to form supercritical CO2 containing a determined modifier concentration; the supercritical CO2 containing the determined modifier concentration is injected into the lower cabin of the N recovery tanks by the third high-pressure pump until the pressure of the ultrapure water in the upper cabin reaches balance;

[0022] The subcritical fluid of the heated organic pigment is guided into the lower cabin of the recovery tank by the electromagnetic valve, and is sequentially injected into the N recovery tanks according to a determined time.

[0023] S4: The subcritical fluid containing the organic pigment in the recovery tank is contacted with supercritical CO2 containing a certain modifier concentration, and the organic pigment nanocrystals are precipitated by using the large difference in solubility of the organic pigment between the subcritical good solvent and supercritical CO2, and at the same time, the surface of the organic pigment nanocrystals is modified by the modifier carried by the supercritical CO2 by using the feature that the surface tension of supercritical CO2 is zero;

[0024] S5: In each recovery tank, the dispersion liquid of the surface-modified organic pigment nanoparticles is obtained after a set time, the bottom electromagnetic valve of the recovery tank is opened to transfer the dispersion liquid containing the organic pigment nanoparticles to the product tank, and after the nanoparticle dispersion liquid in all the recovery tanks is collected into the product tank, the recovery tanks are replenished with ultrapure water and supercritical CO2 containing a certain modifier concentration, which are sequentially supplied into the upper and lower compartments of each recovery tank, and the next round of product preparation is performed.

[0025] Further, the continuous synthesis device further comprises a circulating tank of the good solvent solution of the organic pigment, and when the recovery tank is in the state of replenishment in step S5, or before the good solvent solution of the organic pigment reaches the stable subcritical condition in step S2, the subcritical fluid of the organic pigment generated in the lower compartment of the circulating tank is received through the pipeline, and the good solvent solution of the organic pigment in the lower compartment of the circulating tank is recovered into the circulating tank through the ball valve.

[0026] Further, the upper compartment of the circulating tank is filled with ultrapure water to ensure that the pressure of the entire system can be stably maintained at the same set pressure during the synthesis of the organic pigment nanocrystals.

[0027] Further, a filter is arranged at the inlet of the back pressure valve to prevent the back pressure valve from being easily blocked or the system pressure from being unstable during the continuous synthesis of the nanocrystals.

[0028] Further, the solution of the organic pigment and the good solvent is heated by the first heating device in step S2, and the second heating device is arranged between the third high-pressure pump and the recovery tank, which is used to ensure that the mixed fluid after the subcritical fluid containing the organic pigment is contacted with supercritical CO2 is still in a supercritical state under different high-pressure pump flow rate ratio conditions.

[0029] Further, the product tank in step S5 is pre-filled with a small amount of liquid CO2 before collecting the dispersion liquid of the organic pigment nanoparticles, so that when all the liquid in the recovery tank is moved to the product tank, the CO2 in the product tank cannot be liquefied.

[0030] Further, a quick pressure reducing device is arranged between the recovery tank and the product tank, which can reduce the pressure in the recovery tank, so that the dispersion liquid of the organic pigment nanoparticles can quickly flow into the product tank.

[0031] Further, a cooling device is arranged on the conveying pipeline, which can precisely control the suitable precipitation conditions of the organic pigment nanoparticles by adjusting the temperature and the quick injection amount of the supersaturated organic pigment subcritical solution.

[0032] Based on the preparation device, the application further provides another preparation method of the modified organic pigment nanocrystal for photoresist, which comprises the following steps:

[0033] A1: dissolve a slight excess of the organic pigment in a good solvent, then filter and put into a circulating tank for standby;

[0034] A2: if the heat resistance of the organic pigment is poor and the solubility in the good solvent is also limited, the organic solvent is separately introduced into the pipeline system by the first high-pressure pump and heated to high temperature, and the stable dispersion liquid of the organic pigment in the good solvent at normal temperature introduced by the second high-pressure pump is mixed at the temperature control point T1, so that the solution containing the organic pigment can reach the subcritical fluid state with high solubility in the shortest possible time after mixing;

[0035] A3: provide a continuous synthesis device, which comprises N recovery tanks and a back pressure valve, and the N recovery tanks are respectively No. 1 recovery tank, No. 2 recovery tank,..., and No. N recovery tank, each recovery tank is divided into an upper cabin and a lower cabin, a smooth movable piston is arranged between the two cabins, the upper cabin of the recovery tank is injected with ultrapure water for pressure balance, the system pressure is set by the back pressure valve, and the pressure in the recovery tank is adjusted to the system pressure by the piston;

[0036] The modifier and the supercritical CO2 are mixed to form supercritical CO2 containing a certain concentration of the modifier; the supercritical CO2 containing the certain concentration of the modifier is injected into the lower cabin of the N recovery tanks by the third high-pressure pump until the pressure of the ultrapure water in the upper cabin reaches balance;

[0037] The heated subcritical fluid containing the organic pigment is introduced into the lower cabin of the recovery tank by the electromagnetic valve, and is sequentially injected into the N recovery tanks according to the certain time;

[0038] A4: The subcritical fluid of organic pigment in the recovery tank is contacted with supercritical CO2 containing a certain modifier concentration, and the organic pigment nanocrystals are precipitated by using the great difference in solubility of the organic pigment between the subcritical good solvent and supercritical CO2, and meanwhile, the surface of the organic pigment nanocrystals is modified by the modifier carried by the supercritical CO2 due to the feature of zero surface tension of the supercritical CO2;

[0039] A5: The dispersion liquid of the surface-modified organic pigment nanoparticles is obtained in each recovery tank when a set time is reached, the bottom electromagnetic valve of the recovery tank is opened to transfer the dispersion liquid containing the organic pigment nanoparticles into the product tank, and when the nanoparticle dispersion liquid in all the recovery tanks is collected into the product tank, the recovery tanks are replenished with ultrapure water and supercritical CO2 containing a certain modifier concentration, which are sequentially supplied into the upper and lower compartments of each recovery tank, and the next round of product preparation is performed.

[0040] The back pressure valve in the application is used to set the pressure of the whole system, the upper and lower compartments in the recovery tank are designed to separate the dispersion liquid containing nanoparticles from the pure water system maintaining the pressure, and the nanoparticles are prevented from contacting the back pressure valve as much as possible to protect the back pressure valve from being blocked or damaged due to the mixing of nanoparticles, and the pressure in the recovery tank can be adjusted by the movement of the piston to maintain the whole system at the set pressure of the back pressure valve.

[0041] In the application, the upper part of the recovery tank is connected with the pure water tank through a pure water conveying pipeline and an electromagnetic valve. The lower part of the recovery tank is connected with a conveying pipeline (a fine tube containing an organic crystalline subcritical solution) through an electromagnetic valve, and there is only one electromagnetic valve on the pipeline leading to the recovery tank which can be in the ON state and can be sequentially switched by the controller at a certain time. The purpose of this is to continuously synthesize nanocrystals under stable conditions.

[0042] The application utilizes the great difference in solubility of the organic pigment between the subcritical good solvent and supercritical CO2 to precipitate the organic pigment nanocrystals, and selectively performs surface modification of the nanocrystals by using the solubility of supercritical CO2 for organic compounds and the feature of zero surface tension to make the nanocrystals more easily form a stable and uniform dispersion liquid in the subsequent color resist color paste.

[0043] The principle of selectively performing surface modification of the nanocrystals is as follows: the systems of photoresists are different, and the resins and solvents in the color paste are also different, and in order to realize uniform and stable dispersion of the nanopigment in different photoresist systems, the surface of the nanopigment needs to be modified to be suitable for the resins and solvents. The good solubility of supercritical CO2 (or with a small amount of lower alcohol) for low molecular organic compounds and the feature of zero surface tension can provide the possibility for such selective and effective modification.

[0044] The present application adopts the method of continuously injecting a small amount of subcritical state fluid of organic solvent in which as much organic pigment as possible is dissolved into a supercritical CO2 fluid in which modifier molecules are dissolved in a proper concentration, and then rapidly releasing CO2 gas (which can be recycled in mass production) by rapid decompression, while the surfaces of all precipitated particles are coated with modifier molecules to form proper surface modification.

[0045] Advantages: Compared with the prior art, the present application has the following advantages:

[0046] 1. The present application forms a complete set of process preparation procedures through the construction of a tubular supercritical fluid continuous synthesis device, realizes the perfect combination of reprecipitation method and supercritical CO2 antisolvent method, improves the performance of organic pigment nanocrystals, realizes the continuous synthesis of organic pigment nanocrystals, solves the technical problems of intermittent operation and poor reproducibility of nanocrystal synthesis in the existing reprecipitation method and supercritical CO2 antisolvent method, and meets the mass production demand of organic pigment nanocrystals.

[0047] 2. The present application essentially provides a continuous synthesis method of nanometer pigments, thereby avoiding the safety operation problems caused by the use of large-capacity high-temperature high-pressure vessels in general intermittent supercritical CO2 antisolvent method for mass production. The fine tube supercritical fluid continuous synthesis system provided by the present application disperses the large-capacity equipment required for mass production into multiple small-capacity recovery tanks for continuous and stable operation, which not only solves the safety operation problem of high-temperature high-pressure large-capacity equipment in the supercritical CO2 antisolvent method for mass production, but also can increase the number of recovery tanks according to the production capacity, and has the function of adjustable mass production capacity.

[0048] 3. The present application takes advantage of the huge difference in solubility of organic pigments between subcritical good solvents and supercritical CO2, and at the same time of the precipitation of organic pigment nanocrystals, uses the solubility and zero surface tension of supercritical CO2 for organic compounds to selectively implement the surface modification of nanocrystals, so that it is easier to form a stable and uniform dispersion liquid in the subsequent color photoresist color paste, thereby improving the performance of color photoresist.

[0049] 4. In the present application, the supercritical CO2 containing a certain concentration of modifier and the subcritical fluid of organic pigment can maintain the supercritical state of the mixed fluid, so that the modifier can better complete the surface modification of nanocrystals and improve the use effect of organic pigment nanocrystals.

[0050] 5、The size of the organic pigment synthesized / processed in the present application is smaller, and the particle size distribution is narrower, and it is easier to form uniform and stable dispersion. From the display effect of the final product, its color gamut is wider, color uniformity & saturation is higher, and the pass rate contrast is also higher, and more fine color display effect can be achieved. The organic pigment processing method used in the present application is suitable for the synthesis of all organic pigment nanoparticles with crystallinity. The preparation method of the organic pigment nanoparticles has the characteristics of controllable nanocrystal size, high dispersibility, low cost, stable effect, good reproducibility, etc. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 is a schematic diagram of the reprecipitation method;

[0052] Figure 2 is a schematic diagram of the supercritical CO2 anti-solvent method;

[0053] Figure 3 is a schematic diagram of the tubular supercritical fluid continuous synthesis device in the present application. DETAILED DESCRIPTION

[0054] The present application will be further illustrated below in conjunction with the drawings and specific examples, and it should be understood that these examples are only used to illustrate the present application and are not used to limit the scope of the present application. After reading the present application, those skilled in the art can make various equivalent modifications of the present application, which all fall within the scope defined by the appended claims.

[0055] Example 1:

[0056] As Figure 3As shown, the embodiment provides a tubular supercritical fluid continuous synthesis device, which comprises a conveying pipeline 1, a circulating tank 2, a product tank 12, a non-pulsating first high-pressure pump 3, a non-pulsating third high-pressure pump 10, a CO2 cylinder 11, a back pressure valve 14, four recovery tanks connected in parallel, which are a No. 1 recovery tank, a No. 2 recovery tank, a No. 3 recovery tank and a No. 4 recovery tank, a circulating tank, which is a No. 5 circulating tank here; the back pressure valve 14 is connected with the No. 1 to No. 4 recovery tanks and the No. 5 circulating tank, a filter 13 is arranged at the inlet of the back pressure valve 14, each of the four recovery tanks is provided with a high-speed magnetic stirring or an ultrasonic device to ensure that the substances in the recovery tank can be uniformly dispersed instantaneously, each of the four recovery tanks is divided into an upper cabin and a lower cabin, a smooth-moving piston 7 is arranged between the upper cabin and the lower cabin, the upper part of the recovery tank is connected with a pure water tank through a pure water conveying pipeline and a solenoid valve, the lower part of the recovery tank is connected with the conveying pipeline 1 (a thin tube containing an organic crystalline subcritical solution) through a solenoid valve, a first heating device 4 is arranged on the conveying pipeline 1, the inlet end of the first heating device 4 is connected with the non-pulsating first high-pressure pump 3 through the conveying pipeline 1, a nitrogen-treated pipeline 5 is arranged between the outlet end of the first heating device 4 and the conveying pipeline 1 to perform nitrogen treatment to improve the corrosion resistance of the inner wall of the stainless steel tube to the supercritical fluid, the conveying pipeline 1 is connected with the lower cabin of the recovery tank and the No. 5 circulating tank, a cooling device 6 is further arranged on the conveying pipeline 1, the CO2 cylinder 11 is connected with a CO2 pipeline 9 through the non-pulsating third high-pressure pump 10, a second heating device 8 is arranged on the CO2 pipeline 9, the CO2 pipeline 9 is connected with the lower cabin of each of the four recovery tanks, the upper cabin of the recovery tank is injected with super-pure water for pressure balance through a water pump, the bottom of each of the four recovery tanks is connected with the product tank 12 through a coaxial nozzle, and a rapid pressure reduction device 17 is arranged between the four recovery tanks and the product tank 12, the bottom of the No. 5 circulating tank is provided with a ball valve 15, and the outlet of the ball valve 15 is located above the circulating tank 2.

[0057] The above-mentioned tubular supercritical fluid continuous synthesis device in the embodiment is used for preparing modified organic pigment nanocrystals, and the specific preparation method is as follows:

[0058] The organic pigment in this embodiment is Pc-G (CAS No. 14832-14-5), and the good solvent is DMSO (CAS No. 67-68-5), both of which are reagent grade with a purity of 99.9%. The source of liquefied CO2 is a 40L CO2 steel cylinder 11 with an industrial purity of 99.8%. The Pc-G concentration is set at 40mg / ml, the back pressure valve 14 pressure is set at 20MPa, the flow rate of the non-pulsating first high-pressure pump 3 is set at 3ml / min, and T1 = 90°C. The recovery tank is controlled by an electromagnetic valve on the pipeline to switch every 10s, which is equivalent to 0.5ml of DMSO solution containing Pc-G organic pigment being injected into 50ml of supercritical CO2 through a 22G syringe needle. The purpose of the sequential switching is to quickly and uniformly precipitate the organic pigment in the super-high-ratio non-good solvent (here referring to supercritical CO2), so as to obtain organic nanocrystals with stable physical properties in continuous synthesis.

[0059] Reference Figure 3 , specifically including the following steps:

[0060] 1) Adjust the solubility of the organic pigment in the good solvent to a slightly supersaturated solution at room temperature, and then transfer it to the circulating tank 2 after filtration (no obvious precipitate is observed) for use;

[0061] 2) Set the system pressure through the back pressure valve 14, and adjust the pressure in the upper and lower compartments of each recovery tank to the set system pressure through the movement of the piston 7. Mix the supercritical CO2 in the CO2 steel cylinder 11 with the modifier (oleic acid amine / anhydrous ethanol = 0.01g / 1ml) on the CO2 pipeline 9 to form supercritical CO2 containing a certain concentration of modifier (1ml of oleic acid amine ethanol / 100ml of supercritical CO2), and then heat it to 70°C through the second heating device 8. Then, the supercritical CO2 is introduced into the lower compartments of the No. 1 recovery tank, the No. 2 recovery tank, the No. 3 recovery tank and the No. 4 recovery tank respectively through the control of the electromagnetic valve, and the ultrapure water is injected into the upper compartments of the four recovery tanks through the high-pressure water pump, so that the pressure in the four recovery tanks is balanced, and the pressure in the four recovery tanks can be maintained at the system pressure set by the back pressure valve 14;

[0062] 3) The organic pigment in this embodiment has good heat resistance and sufficient solubility in the good solvent. The solution of the organic pigment and the good solvent in the circulating tank 2 is introduced into the delivery pipeline 1 through the non-pulsating first high-pressure pump 3, and heated to the subcritical state of the maximum solubility of the organic pigment through the first heating device 4. In this embodiment, T1 = 90°C;

[0063] 4) The subcritical fluid of the heated organic pigment is fully homogenized through the nitrogenized stainless steel pipeline 5, and then injected into the lower compartments of the four recovery tanks through the electromagnetic valve control in the set sequence.

[0064] The lower chamber of the four recovery tanks contains subcritical fluid of organic pigment, which is in contact with supercritical CO2 containing a certain modifier concentration. The organic pigment nanocrystals are precipitated by using the large difference in solubility of the organic pigment between the subcritical good solvent and supercritical CO2. At the same time, the surface of the organic pigment nanocrystals is modified by the modifier carried by the supercritical CO2 by using the feature that the surface tension of supercritical CO2 is zero;

[0065] 5) After a set time (5 seconds after the injection of the DMSO solution of the organic pigment in this embodiment) is reached in each recovery tank, a dispersion of the surface-modified organic pigment nanoparticles is obtained. Under the action of the rapid pressure reduction device 17, the bottom electromagnetic valve of the recovery tank is sequentially opened to transfer and collect the dispersion containing the organic pigment nanoparticles into the product tank 12. The product tank 12 can be pre-filled with a small amount of liquid CO2. When all the liquids in the recovery tanks are moved to the product tank, the CO2 in the product tank 12 cannot be completely liquefied;

[0066] When the nanoparticle dispersions in all the recovery tanks are collected into the product tank 12, the dispersion in the product tank 12 is transferred to other containers through the discharge valve, and the discharge valve and the rapid pressure reduction device are closed, preparing for the collection of the next round of products;

[0067] The four recovery tanks are replenished with ultrapure water and supercritical CO2 containing a certain modifier concentration, which are sequentially replenished into the upper and lower chambers of the recovery tanks, preparing for the next round of product preparation.

[0068] During the replenishment of the recovery tanks, or during the period when the solution of the good solvent containing the organic pigment has not yet reached the stable subcritical condition after heating, the subcritical fluid of the organic pigment generated in the delivery pipeline 1 is introduced into the lower part of the No. 5 circulating tank. The upper chamber of the No. 5 circulating tank is injected with ultrapure water by a water pump to achieve pressure balance in the No. 5 circulating tank, so that the entire system can be maintained at a set pressure condition. The purpose of this is to maintain the uniformity and stability of the experimental conditions of the system during each round of product preparation. The subcritical fluid of the organic pigment (i.e., the solution of the organic pigment and the good solvent) in the No. 5 circulating tank is cooled and depressurized and then returned to the circulating tank 2 through the ball valve 15 for recycling.

[0069] Example 2:

[0070] As Figure 3As shown, the embodiment provides a tubular supercritical fluid continuous synthesis device, which comprises a conveying pipeline 1, a circulating tank 2, a product tank 12, a first high-pressure pump 3, a second high-pressure pump 16 (slurry pump, uniform suspension can also stabilize the feeding), a third high-pressure pump 10, a CO2 cylinder 11, a back pressure valve 14, four recovery tanks connected in parallel, which are a No. 1 recovery tank, a No. 2 recovery tank, a No. 3 recovery tank and a No. 4 recovery tank, a circulating tank, which is a No. 5 circulating tank here; the back pressure valve 14 is connected with the No. 1-4 recovery tanks and the No. 5 circulating tank, and a filter 13 is arranged at the inlet of the back pressure valve 14; each of the four recovery tanks is provided with a high-speed magnetic stirring or an ultrasonic device to ensure that the substances in the recovery tank can reach a uniform dispersion state instantaneously, and each of the four recovery tanks is divided into an upper cabin and a lower cabin, and a piston 7 capable of smoothly moving is arranged between the upper cabin and the lower cabin; a first heating device 4 is arranged on the conveying pipeline 1, the inlet end of the first heating device 4 is connected with the first high-pressure pump 3 through the conveying pipeline 1, the outlet end of the first heating device 4 is connected with the second high-pressure pump 16, the upper cabin of the recovery tank is connected with a pure water tank through a pure water conveying pipeline and a solenoid valve, the lower cabin of the recovery tank is connected with the conveying pipeline 1 (a thin pipeline containing an organic pigment subcritical solution) through a solenoid valve, a nitrogenized stainless steel pipeline 5 is arranged between the outlet end of the first heating device 4 and the conveying pipeline 1, the stainless steel pipeline 5 is used to improve the corrosion resistance of the inner wall of the stainless steel pipeline to the supercritical fluid, the conveying pipeline 1 is connected with the lower cabin of the recovery tank and the No. 5 circulating tank, a cooling device 6 is further arranged on the conveying pipeline 1, the CO2 cylinder 11 is connected with a CO2 pipeline 9 through the third high-pressure pump 10, a second heating device 8 is arranged on the CO2 pipeline 9, the CO2 pipeline 9 is connected with the lower cabin of each of the four recovery tanks, and the upper cabin of the recovery tank is injected with ultrapure water for pressure balance through a water pump, the bottom of each of the four recovery tanks is connected with the product tank 12 through a coaxial nozzle, and a rapid decompression device 17 is arranged between the four recovery tanks and the product tank 12, the bottom of the No. 5 circulating tank is provided with a ball valve 15, and the outlet of the ball valve 15 is located above the circulating tank 2.

[0071] The above-mentioned tubular supercritical fluid continuous synthesis device in the embodiment is used for preparing modified organic pigment nanocrystals, and the specific preparation method is as follows:

[0072] In the embodiment, Pc-G (CAS No. 14832-14-5) is selected as the organic pigment, DMSO (CAS No. 67-68-5) is selected as the good solvent, and the purity of the reagent grade is 99.9%, the source of liquefied CO2 is a 40L CO2 cylinder 11 with an industrial purity of 99.8%, the concentration of the dispersion liquid of Pc-G is set to 80mg / ml, the pressure of the back pressure valve 14 is set to 20MPa, the flow rate of the first high-pressure pump 3 is set to 3ml / min, the flow rate of the second high-pressure pump is set to 1ml / min, and T1=120℃.

[0073] Referring to Figure 3 , specifically comprising the following steps:

[0074] 1) Pc-G of a set concentration is dissolved & dispersed in DMSO, and then introduced into the system by a non-pulsating second high-pressure pump 16; pure DMSO solvent is introduced into the system by a non-pulsating first high-pressure pump 3, mixed with the Pc-G DMSO dispersion at room temperature at a T1 temperature control point, and rapidly heated to 120°C;

[0075] 2) The system pressure (20 MPa) is set by a back pressure valve 14, the pressure in the upper and lower compartments of each recovery tank is adjusted to the set system pressure by the movement of the piston 7, the supercritical CO2 in the CO2 cylinder 11 and the modifier are mixed on the CO2 pipeline 9 to form supercritical CO2 containing a certain modifier concentration, and after heating to 70°C by the second heating device 8, they are introduced into the lower compartments of the No. 1 recovery tank, the No. 2 recovery tank, the No. 3 recovery tank and the No. 4 recovery tank respectively by the control of the electromagnetic valve, and the ultrapure water is injected into the upper compartments of the four recovery tanks by the water pump, so that the pressure in the four recovery tanks is balanced, and the pressure in the four recovery tanks can be maintained at the system pressure set by the back pressure valve 14;

[0076] 3) This embodiment is suitable for organic pigments with poor heat resistance and limited solubility in good solvents. An organic solvent is introduced into the pipeline system by a non-pulsating first high-pressure pump 3, heated to a specified high temperature by a first heating device 4, and at the same time, a stable dispersion of the organic pigment in the good solvent at room temperature is introduced into the pipeline system by a non-pulsating second high-pressure pump 16, so that the high-temperature organic solvent and the stable dispersion of the organic pigment in the good solvent at room temperature are mixed at the temperature control point T1, so that the organic pigment reaches a subcritical fluid state with high solubility in the shortest possible time after mixing;

[0077] 4) After the subcritical fluid containing the organic pigment after heating is homogenized by the nitrogenized stainless steel pipeline 5, it is injected into the lower compartments of the four recovery tanks in a set order by the control of the electromagnetic valve;

[0078] The subcritical fluid of the organic pigment in the lower compartments of the four recovery tanks is in contact with the supercritical CO2 containing a certain modifier concentration, and the organic pigment nanocrystals are precipitated by taking advantage of the large difference in solubility between the organic pigment in the subcritical good solvent and the supercritical CO2, and at the same time, the surface of the organic pigment nanocrystals is modified by the modifier carried by the supercritical CO2 by taking advantage of the zero surface tension of the supercritical CO2;

[0079] 6) After the set time (5 seconds after the injection of the DMSO solution of the organic pigment in this embodiment) is reached in each recovery tank, the dispersion of the surface-modified organic pigment nanoparticles obtained is transferred to the product tank 12 under the action of the rapid decompression device 17, and the bottom electromagnetic valve of each recovery tank is sequentially opened to collect the dispersion containing the organic pigment nanoparticles in the product tank 12. The product tank 12 can be pre-filled with a small amount of liquid CO2, and when all the liquid in the recovery tanks is moved to the product tank, the CO2 in the product tank 12 cannot be completely gassed;

[0080] When the nanoparticle dispersions in all the recovery tanks are collected in the product tank 12, the dispersion in the product tank 12 is transferred to other containers through the discharge valve, and the discharge valve and the rapid decompression device are closed;

[0081] The four recovery tanks are replenished with ultrapure water and supercritical CO2 containing a certain concentration of the modifier, which are sequentially added to the upper and lower compartments of each recovery tank, respectively, for the next round of product preparation.

[0082] During the replenishment of the recovery tanks, or during the period when the solution of the good solvent containing the organic pigment has not yet reached the stable subcritical condition after heating, the subcritical fluid of the organic pigment generated in the delivery pipeline 1 is introduced into the lower part of the No. 5 circulating tank, and ultrapure water is injected into the upper compartment of the No. 5 circulating tank through the water pump to achieve pressure balance in the No. 5 circulating tank, so that the entire system can be maintained at a set pressure condition. The purpose of this is to maintain the uniformity and stability of the experimental conditions of the system during each round of product preparation. The solution of the good solvent containing the organic pigment in the No. 5 circulating tank is cooled and decompressed, and then returned to the circulating tank 2 through the ball valve 15. After the organic pigment is added to a set concentration in a proportion, it is recycled for use.

[0083] Compared with Embodiment 1, in the case where the supercritical temperature of the solvent in Embodiment 1 is too low or the heat resistance of the organic pigment is poor, the early warming condition may cause the early precipitation of the organic pigment in the supercritical state (causing pipeline blockage) or decomposition of the organic pigment. The operation mode adopted in this embodiment is beneficial to expanding the adjustment range of various conditions after the mixing of the two fluids and accurately adjusting the temperature control of each section of the pipeline, which can effectively solve the above-mentioned problems, but the recovery efficiency of the organic pigment nanocrystals may be lower than that of Embodiment 1.

[0084] Embodiment 3:

[0085] In this embodiment, the Pc-G nanocrystals are synthesized by the precipitation method shown in Embodiment 1, Embodiment 2, and Figure 1

[0086] ​The process of the precipitation method is as follows: the concentration of the DMSO solution of Pc-G is 40 mg / 1 ml, the temperature is 60°C, the pushing speed of the micro-injector is 6 ml / 1 min, the model of the injector needle tube is 19G, the volume ratio of distilled water to the DMSO solution of Pc-G is 300:1, the speed of the magnetic stirrer in the container of distilled water is set to be no less than 800 rpm, after the dropping of the DMSO solution of Pc-G is completed, the stirring is continued for 20 min and then stopped, and the super-speed centrifuge is used for recovery.

[0087] The performance comparison data of the finally obtained Pc-G nanocrystals are shown in the following table:

[0088]

[0089] The particle size in the above table is the test result of the nanoparticle size instrument

[0090] As shown in the above table, the particle size of the Pc-G nanocrystals obtained in Examples 1 and 2 is smaller, the particle size distribution is narrower, and it is easier to form a uniform and stable dispersion, and the final dispersion state is obviously better than that of the precipitation method.

[0091] Example 4:

[0092] In this example, the precipitation methods shown in Examples 1, 2 and Figure 1 The performance comparison data of the color paste prepared from the Pc-G nanocrystals are as follows:

[0093] The preparation method of the color paste is as follows:

[0094] Sand grinding: in a vertical sand mill with a capacity of 0.25 L, 20 g of Pc-G pigment and 200 g of zirconium balls (0.3 mm), 30 g of diethylene glycol (DEG), and 2 g of dioctyl sodium sulfosuccinate (DSS) are added and maintained at 40°C, and sand grinding is performed for 6 hours. After sand grinding, the pigment is washed with water to a conductivity of less than 0.08 us / cm, and the purpose of water washing is to wash away the soluble impurities and DEG, and DSS is coated on the Pc-G pigment by sand grinding; after centrifugation, drying is performed at 80°C to obtain modified Pc-G pigment.

[0095] Dispersion ratio: 14.29 g of acrylic resin (solid content 35%), 7.14 g of dispersant BYK2001 (solid content 46%), 68.57 g of solvent PMA (propylene glycol methyl ether acetate), and 10 g of modified Pc-G pigment are added in a stainless steel container according to the above ratio, 150 g of 0.2 mm zirconium balls are added, and the mixture is dispersed in a shaker for 4 hours to obtain a color paste for evaluation.

[0096] Sample preparation and testing: 1 ml of the color paste was spin-coated on a standard glass sheet at 1200 rpm. The coated glass sheet was placed on a hot plate at 120°C for 1 min, and then heated in an oven at 230°C for 30 min. The colorimetric values (x, y) and brightness (Y) were measured, and the contrast ratio was measured using a contrast meter.

[0097] Comparative Example Example 1 Example 2 Precipitation method x 0.2247 0.2705 0.2628 0.2536 y 0.442 0.442 0.442 0.442 Brightness (Y) 48.9 68.2 61.8 57.1 Contrast 6535 12967 12145 10894 Pass rate 91.3％ 93.9％ 93.6％ 92.5％

[0098] The comparative examples were obtained by directly grinding and dispersing commercially available Pc-G pigments according to the above procedure.

[0099] As shown by the comparison data in the above table, the brightness, contrast ratio and transmittance of Examples 1 and 2 are superior to those of the comparative examples and the precipitated method.

Claims

1. An apparatus for preparing modified organic pigment nanocrystals for photoresist, characterized in that, The system includes a conveying pipeline, a circulation tank, a product tank, a first high-pressure pump, a third high-pressure pump, a CO2 pipeline, and a continuous synthesis unit. The continuous synthesis unit includes parallel-connected recovery tanks and a back pressure valve, each connected to one of the recovery tanks. Each recovery tank is divided into an upper compartment and a lower compartment, with a smoothly movable piston between the upper and lower compartments. A first heating device is installed on the conveying pipeline. The conveying pipeline is connected to the circulation tank via the first high-pressure pump. The first high-pressure pump pumps the solution of organic pigments and good solvents from the circulation tank into the conveying pipeline. A heating device is used to heat the solution of organic pigment and good solvent to the subcritical state of maximum solubility of organic pigment. The delivery pipeline is connected to the lower compartment of the recovery tank. The CO2 pipeline is connected to the lower compartment of the recovery tank. The CO2 pipeline is connected to a supercritical CO2 source through a third high-pressure pump. The CO2 pipeline is also connected to a modifier source. The upper compartment of the recovery tank is filled with ultrapure water for controlling pressure balance. The product tank is located at the bottom of the recovery tank to receive the dispersion of surface-modified organic pigment nanoparticles.

2. The apparatus for preparing modified organic pigment nanocrystals for photoresist according to claim 1, characterized in that, The continuous synthesis apparatus also includes a circulation tank, a back pressure valve connected to the circulation tank, a delivery pipeline connected to the lower compartment inside the circulation tank, an upper area inside the circulation tank filled with ultrapure water, and a circulation trough connected to the bottom of the circulation tank.

3. The apparatus for preparing modified organic pigment nanocrystals for photoresist according to claim 2, characterized in that, A ball valve is installed at the bottom of the circulation tank.

4. The apparatus for preparing modified organic pigment nanocrystals for photoresist according to claim 1, characterized in that, A filter is installed at the inlet of the back pressure valve.

5. The apparatus for preparing modified organic pigment nanocrystals for photoresist according to claim 1, characterized in that, A second heating device is provided between the third high-pressure pump and the recovery tank. The second heating device is used to ensure that the mixed fluid containing organic pigments remains in a supercritical state after contact with supercritical CO2.

6. The apparatus for preparing modified organic pigment nanocrystals for photoresist according to claim 1, characterized in that, A rapid pressure reduction device is installed between the recycling tank and the product tank.

7. The apparatus for preparing modified organic pigment nanocrystals for photoresist according to claim 2, characterized in that, A cooling device is installed on the delivery pipeline.

8. The apparatus for preparing modified organic pigment nanocrystals for photoresist according to claim 1, characterized in that, A second high-pressure pump is connected to the outlet of the first heating device on the conveying pipeline. The second high-pressure pump is used to introduce the stable dispersion of room-temperature organic pigments in a good solvent into the conveying pipeline.

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