CN112595033B - Preparation method of polycarbonate powder with stable color - Google Patents
Preparation method of polycarbonate powder with stable color Download PDFInfo
- Publication number
- CN112595033B CN112595033B CN202011454464.1A CN202011454464A CN112595033B CN 112595033 B CN112595033 B CN 112595033B CN 202011454464 A CN202011454464 A CN 202011454464A CN 112595033 B CN112595033 B CN 112595033B
- Authority
- CN
- China
- Prior art keywords
- carrier gas
- temperature
- polycarbonate powder
- dryer
- drying
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B3/00—Drying solid materials or objects by processes involving the application of heat
- F26B3/02—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air
- F26B3/06—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air the gas or vapour flowing through the materials or objects to be dried
- F26B3/08—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air the gas or vapour flowing through the materials or objects to be dried so as to loosen them, e.g. to form a fluidised bed
- F26B3/084—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air the gas or vapour flowing through the materials or objects to be dried so as to loosen them, e.g. to form a fluidised bed with heat exchange taking place in the fluidised bed, e.g. combined direct and indirect heat exchange
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B11/00—Machines or apparatus for drying solid materials or objects with movement which is non-progressive
- F26B11/12—Machines or apparatus for drying solid materials or objects with movement which is non-progressive in stationary drums or other mainly-closed receptacles with moving stirring devices
- F26B11/16—Machines or apparatus for drying solid materials or objects with movement which is non-progressive in stationary drums or other mainly-closed receptacles with moving stirring devices the stirring device moving in a vertical or steeply-inclined plane
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B21/00—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
- F26B21/001—Drying-air generating units, e.g. movable, independent of drying enclosure
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B21/00—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
- F26B21/06—Controlling, e.g. regulating, parameters of gas supply
- F26B21/10—Temperature; Pressure
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B25/00—Details of general application not covered by group F26B21/00 or F26B23/00
- F26B25/005—Treatment of dryer exhaust gases
Abstract
The invention relates to a preparation method of polycarbonate powder with stable color, which comprises the steps of firstly, putting crude polycarbonate powder into a fluidized bed dryer for drying, removing partial dichloromethane and water, and removing polycarbonate powder with the particle size of less than 100 mu m by a cyclone separator; then the mixture enters a paddle type dryer for drying, and dichloromethane, water and hydrogen chloride gas generated by decomposition of dichloromethane are further removed; and finally, drying in a tubular dryer, and deeply removing dichloromethane and water to obtain the polycarbonate powder with stable color. The invention integrates three drying modes of a fluidized bed, a paddle type dryer and a shell and tube dryer, and designs a dustproof distributor in the paddle type dryer, thereby effectively solving the problems of oxidation yellowing and color fluctuation of polycarbonate in the production process, and improving the quality of polycarbonate products, wherein the content of dichloromethane is lower than 200ppm, the content of water is lower than 200ppm, and the content of hydrochloric acid is lower than 0.1ppm.
Description
Technical Field
The invention belongs to the technical field of polycarbonate preparation, and relates to a preparation method of polycarbonate powder with stable color.
Background
Polycarbonate (PC for short) is a colorless and transparent thermoplastic material, and has excellent performances of colorless and transparency, high strength and elastic coefficient, high impact strength, wide application range, good fatigue resistance, good weather resistance and the like. However, the aromatic polycarbonate is easy to yellow in the production process, has poor color stability and seriously restricts the downstream application.
Patent CN 103640108B discloses that a two-stage drying process method is adopted to dry polycarbonate powder, hot nitrogen is adopted as carrier gas to dry, and the nitrogen is recycled, so that the problem of recycling dichloromethane solvent in the process of drying the polycarbonate powder is solved, and meanwhile, the hidden accident danger that dust in a polycarbonate drying system is flammable and explosive is avoided.
Patent CN 106459425B, which is a device for removing residual organic solvent from polycarbonate powder, controls the drying temperature to be 5 to 15 ℃ lower than the glass transition temperature of polycarbonate, whereby the polycarbonate powder is not welded to the wall surface in the dryer, and thus the polycarbonate powder can be dried efficiently without the risk of deteriorating the quality of the obtained polycarbonate molded article.
The polycarbonate drying method provided by the patent improves the quality of polycarbonate products to a certain extent, but fails to effectively solve the problems of easy yellowing and color fluctuation of the polycarbonate in the production process.
Disclosure of Invention
The invention aims to provide a preparation method of polycarbonate powder aiming at the problems in the prior art, which can effectively solve the problems of easy yellowing and color fluctuation in the existing polycarbonate production process.
In the process of researching a polycarbonate production process, the inventor finds that influencing factors on the color stability of a polycarbonate powder product mainly exist in the drying process, the polycarbonate powder is easy to soften and adhere to the inside of a dryer when the temperature is too high in the drying process, especially, the existence of particles with small particle sizes (< 100 microns) can aggravate the severity of the process, the heat exchange efficiency of the dryer is reduced, the operation cycle of the dryer is influenced, and if a skinned object stays in the dryer for a long time, decomposition and oxidation reactions can occur to cause color fluctuation. In addition, since the polycarbonate contains a small amount of methylene chloride, hydrochloric acid is easily generated by decomposition, and the generated hydrochloric acid not only corrodes equipment, but also easily causes decomposition and oxidation of the polycarbonate, and causes yellowing of the polycarbonate, thereby causing color fluctuation. Therefore, how to prevent the skinning and control the decomposition of dichloromethane to generate hydrochloric acid in the drying process are the key points for solving the color problem of the polycarbonate powder.
To achieve the above object, the present invention provides a method for preparing a color-stable polycarbonate powder, comprising the steps of:
1) Drying the crude polycarbonate powder in a fluidized bed dryer, removing partial dichloromethane and water, and removing polycarbonate powder with the particle size of less than 100 mu m by a cyclone separator;
2) The polycarbonate powder treated in the step 1) enters a paddle type dryer for drying, and dichloromethane, water and hydrogen chloride gas generated by dichloromethane decomposition are further removed;
3) And 2) drying the polycarbonate powder treated in the step 2) in a tubular dryer, and deeply removing dichloromethane and water to obtain the polycarbonate powder with stable color.
In the preparation method, in the step 1), the composition of the crude polycarbonate powder comprises 10-20% of dichloromethane and 20-30% of water by mass;
the coarse polycarbonate powder has a particle size distribution of 10 to 1000 μm, wherein the content of particles having a particle size of <100 μm is 5 to 10 wt.%.
The crude polycarbonate powder source is preferably prepared by preparing a PC slurry from a 18-20wt% solution of polycarbonate in methylene chloride by means of a kneader, removing methylene chloride to 10-20wt% by introducing steam into the PC slurry, and removing water to 20-30% by means of centrifugation.
In the preparation method, in the step 1), high-temperature gas is required to be introduced as a carrier gas and a heat source, and the temperature of the high-temperature gas is 100-140 ℃, preferably 110-120 ℃; the water on the surface of the polycarbonate is removed easily, and the carrier gas is used for removing the free water on the surface of the polycarbonate particles in a lower temperature region, so that the hydrochloric acid fluctuation caused by the generation of hydrochloric acid due to high water content in a subsequent high temperature region is avoided.
Preferably, the amount of the high-temperature gas is 1-3Nm in relation to the amount of the crude polycarbonate powder 3 /kg, preferably 1.4-2Nm 3 /kg；
Preferably, the high-temperature gas can be hot air, hot nitrogen and waste carrier gas from the step 2) paddle dryer and the step 3) tubular dryer, and preferably the waste carrier gas from the step 2) paddle dryer and the step 3) tubular dryer is adopted; the waste carrier gas in the subsequent drying step is recycled as the carrier gas and the heat source in the fluidized drying process, the extra waste gas amount is not increased, and the energy utilization rate can be improved.
In the preparation method, in step 1), the crude polycarbonate powder enters a fluidized bed dryer from the top, is in countercurrent contact with high-temperature gas for drying, then gas phase discharged from the top of the fluidized bed dryer enters a cyclone separator, polycarbonate powder with the particle size of more than or equal to 100 mu m is recycled through cyclone separation and returns to the fluidized bed dryer, and the polycarbonate powder discharged from the bottom of the fluidized bed dryer enters a paddle type dryer in step 2); in the step, in order to avoid the bonding of the polycarbonate particles due to the high dichloromethane content, the polycarbonate particles are fluidized, and the water on the surface of the polycarbonate powder is easily volatilized and removed in the state. Firstly, carrier gas is utilized to remove free water on the surface of the polycarbonate particles at a lower temperature region, so that color fluctuation caused by the fact that hydrogen chloride gas generated by decomposing dichloromethane is converted into hydrochloric acid due to high water content in the subsequent drying process of a high temperature region can be avoided.
Preferably, the gas phase after cyclone separation is subjected to fine powder capture by a fine powder capture tower, and then returned to the front-end process for re-dissolution and recovery, and the residual gas phase after capture is sent to a gas recovery system; in the gas phase after the cyclone separation, the content of the polycarbonate powder with the grain diameter less than 100 mu m is more than 90 wt%; the fines capture column is preferably a tray column. The polycarbonate powder with the grain diameter less than 100 mu m is removed from the polycarbonate powder, so that the problems that the fine powder load of a dryer is increased when the powder with the grain diameter less than 100 mu m circularly enters the dryer, and the color fluctuates due to decomposition and oxidation reactions caused by softening and skinning in the dryer can be avoided.
In the preparation method, in the step 1), the separation efficiency of the polycarbonate powder with the grain diameter of less than 100 mu m is more than 60 percent; polycarbonate powder discharged from the bottom of the fluidized bed dryer, wherein the content of particles having a particle size of <100 μm is less than 3% by weight.
In the preparation method, in the step 1), the drying is carried out at the temperature of 110-140 ℃, preferably 120-130 ℃, and the retention time is 0.1-5h, preferably 0.3-1h.
In the preparation method, in the step 1), the polycarbonate powder discharged from the bottom of the fluidized bed dryer comprises, by mass, 5-13% of dichloromethane, 4-10% of water and 0.6-1.5ppm of hydrogen chloride.
In the preparation method, in the step 2), high-temperature carrier gas is required to be introduced in the drying process, water volatilized by powder, dichloromethane, hydrogen chloride generated by decomposition of the dichloromethane and the like are diluted by the high-temperature carrier gas and are timely carried away, so that the drying effect is prevented from being influenced by recondensation in the dryer, and meanwhile, in the step, the paddle type dryer disperses particles by using the stirring paddle, so that the polycarbonate particles are prevented from being bonded due to high dichloromethane content in the drying process;
preferably, the high-temperature carrier gas is selected from high-temperature nitrogen, air and the like, and the temperature of the high-temperature carrier gas is preferably 100-140 ℃;
preferably, the waste carrier gas at the outlet of the paddle dryer in the step 2) can be used as the inlet carrier gas of the fluidized bed dryer in the step 1) to save the use amount of the carrier gas and the energy consumption.
In the step 2), the bottom of the paddle type dryer is also provided with carrier gas dustproof distributors, the number of the carrier gas dustproof distributors is 1-10, preferably 5-8, and the carrier gas dustproof distributors are preferably uniformly distributed at the bottom of the paddle type dryer. In the drying process, partial dichloromethane can be decomposed to generate hydrogen chloride gas under the influence of high-temperature carrier gas, and the hydrogen chloride gas and water form hydrochloric acid. Meanwhile, the carrier gas dustproof distributor can further remove particles with the particle size of less than 100 mu m in the polycarbonate powder.
Furthermore, the carrier gas dustproof distributor comprises an upper part and a lower part, wherein the upper part of the carrier gas dustproof distributor is provided with a double-layer tubular jacket, and the lower part of the carrier gas dustproof distributor is provided with a collecting tank; preferably, the height of the double-layer tubular jacket is 100-400mm, the collecting tank is a horizontal tank body, the diameter is more than 200m, and the length is more than 400mm; the collecting tank is also provided with a carrier gas inlet and a discharge port; preferably, the carrier gas inlet and discharge ports are connected to the exterior of the paddle dryer;
the double-layer tubular jacket comprises an inner tube, an outer tube and an interlayer formed between the two tubes, preferably, the diameter of the inner tube is 20-100mm, and the width of the interlayer is 1-10mm;
the upper end of the interlayer is sealed, and the lower end of the interlayer is communicated with the collecting tank; the upper end of the inner pipe is sealed, and the lower end of the inner pipe is communicated with the collecting tank;
the interlayer is horizontally provided with an annular baffle along an annular gap at a position 10-40mm away from the collecting tank, one end of the annular baffle is fixedly connected to the inner pipe wall, the other end of the annular baffle can rotate downwards along the outer pipe wall, a supporting rod is used for limiting, and the downward rotation angle of the annular baffle is controlled to be less than 45 degrees; the interlayer space is used for collecting the polycarbonate powder separated by the carrier gas dustproof distributor, the function principle is that when the polycarbonate powder accumulated on the annular baffle is less, the annular baffle is in a horizontal closed state, the amount of the accumulated powder is gradually increased, the annular baffle starts to rotate downwards under the action of gravity and is in an open state, the accumulated polycarbonate powder falls into the collecting tank from the annular baffle, and then the annular baffle returns to the horizontal closed state. The annular baffle can rotate downwards and reset along with the change of the accumulation amount of the polycarbonate powder, and the separated polycarbonate powder is collected into the collection tank.
The inner pipe is provided with inner layer distribution holes above the annular baffle, the aperture of the inner layer distribution holes is 0.05-0.3mm, and the opening density (based on the total area of the openings in unit area) is 10-20%. The outer pipe is provided with outer layer distribution holes above the annular baffle, the aperture of the outer layer distribution holes is 0.1-0.5mm, and the opening density (based on the total area of the openings in unit area) is 20-30%. The inner layer is provided with a smaller pore diameter, so that the blockage of pore channels by small-particle polycarbonate powder can be avoided, the outer layer is provided with a larger pore diameter so as to prevent larger-particle polycarbonate powder from entering the interlayer to block, and meanwhile, small particles with the particle size of 50-200 mu m in the polycarbonate powder are intercepted in the interlayer and collected into the collecting tank through the annular baffle.
In the carrier gas dustproof distributor arranged at the bottom of the paddle type dryer in the step 2), firstly, high-temperature carrier gas enters a collecting tank through a carrier gas inlet, then enters an inner pipe upwards, and enters the paddle type dryer through an inner layer distribution hole and an outer layer distribution hole in sequence, and polycarbonate powder dispersed in the stirring paddle dryer is contacted with the carrier gas dustproof distributor, wherein small particles with the particle size of 50-200 mu m enter an interlayer through the outer layer distribution hole, the small particles with the particle size of less than 100 mu m are deeply separated, and then are collected into the collecting tank through an annular baffle plate, and dichloromethane, water and hydrochloric acid volatilized from the powder can be timely carried away.
In the preparation method, in the step 2), the drying is carried out at the temperature of 110-140 ℃, preferably 120-130 ℃, and the retention time is 1-4h, preferably 2-3h.
The preparation process of the present invention, step 2), the polycarbonate powder discharged from the paddle dryer has a content of less than 0.14% by weight with a particle size of < 100. Mu.m.
In the preparation method, in the step 2), the polycarbonate powder discharged from the bottom of the paddle dryer contains 1-4.9% of dichloromethane, 1-3% of water and 0.1-0.3ppm of hydrogen chloride by total mass.
In the preparation method, in the step 3), high-temperature carrier gas is required to be introduced in the drying process, and the high-temperature carrier gas is used as the fluidizing gas and a heat source; and deeply drying and removing dichloromethane and water in the polycarbonate powder by adopting long retention time through the tubular heat exchanger to obtain a polycarbonate powder product with stable color.
Preferably, the high-temperature carrier gas is selected from high-temperature nitrogen, air and the like, and the temperature of the high-temperature carrier gas is preferably 100-140 ℃;
preferably, the waste carrier gas at the outlet of the tubular dryer in the step 3) can be used as the inlet carrier gas of the fluidized bed dryer in the step 1) to save the consumption of the carrier gas and energy consumption.
In the preparation method, in the step 3), the drying is carried out at the temperature of 120-160 ℃, preferably 130-140 ℃, and the retention time is 2-10h, preferably 5-8h.
The preparation process of the present invention, step 3), produces a color-stable polycarbonate powder product having a methylene chloride content of less than 200ppm, a water content of less than 200ppm and a hydrochloric acid (as hydrogen chloride) content of less than 0.1ppm.
Compared with the prior art, the technical scheme of the invention has the beneficial effects that:
according to the invention, three drying modes of a fluidized bed, a paddle type dryer and a shell and tube dryer are comprehensively applied by analyzing influence factors on the color stability of a polycarbonate powder product, and a dustproof distributor is newly designed in the paddle type dryer, so that particles with small particle size (less than 100 mu m) are effectively removed, and the problems of yellow crusts and color fluctuation caused by decomposition and oxidation reactions of the crusts are avoided. Meanwhile, the method also deeply removes dichloromethane, water and hydrogen chloride (hydrochloric acid) generated by decomposition in the drying process, effectively solves the problems of oxidation yellowing and color fluctuation in the production process of the polycarbonate, obtains polycarbonate powder with stable color, and improves the quality of the polycarbonate product.
Drawings
FIG. 1 is a schematic flow chart of the production process of the present invention;
in the figure: 1. crude polycarbonate powder, 2, polycarbonate powder discharged from the bottom of a fluidized bed dryer, 3, polycarbonate powder discharged from the bottom of a paddle dryer, 4, a color-stable polycarbonate powder product obtained from an outlet of a tubular dryer, 5, high-temperature carrier gas, 6, high-temperature carrier gas at an inlet of the tubular dryer, 7, high-temperature carrier gas at an inlet of the paddle dryer, 8, waste carrier gas at an outlet of the tubular dryer, 9, waste carrier gas at an outlet of the paddle dryer, 10, gas phase discharged from the top of the fluidized bed dryer, 11, polycarbonate powder with particle size of more than or equal to 100 mu m entrained by cyclone separation and recovery, 12, gas phase after cyclone separation and 13, residual gas phase after trapping;
FIG. 2 is a schematic view of the distribution of carrier gas dust distributors at the bottom of a paddle dryer;
in the figure: 20. a carrier gas dustproof distributor;
FIG. 3 is a schematic view of a carrier gas dust distributor;
in the figure: 21. inner layer distribution holes 22, outer layer distribution holes 23, annular baffles 24, outer pipe walls 25, inner pipe walls 26, inner pipe carrier gas channels 27, collecting grooves 29, discharge openings 30 and carrier gas inlets;
FIG. 4 is a schematic view of a double-tube jacket structure on the upper part of a carrier gas dustproof distributor;
in the figure: 23. annular baffle, 28, support rod;
FIG. 5 is a schematic diagram of inner pipe distribution holes of a double-layer tubular jacket on the upper part of a carrier gas dustproof distributor;
FIG. 6 is a schematic view of the outer pipe distribution holes of the double-layer pipe type jacket on the upper part of the carrier gas dustproof distributor;
FIG. 7 is a schematic view of the structure of a double-layer tubular jacket ring baffle on the upper part of a carrier gas dustproof distributor.
Detailed Description
The invention is further illustrated with reference to the following specific examples, without limiting the scope of the invention thereto.
Crude polycarbonate powder: preparing PC slurry from 18-20wt% of polycarbonate methylene chloride solution through a kneader, introducing steam into the PC slurry to remove methylene chloride to 10-20wt%, and centrifuging to remove water to 20-30 wt%.
Fluidized bed dryer: punier drying equipment ltd, ZLG1.5 × 7.5.
Paddle dryer: JG-185, a limited institute of chemical and mechanical engineering and Automation research design.
A shell and tube dryer: HZG-3400, a Chinesian chemical machinery and automated research and design institute Co.
A carrier gas dustproof distributor 20 is distributed at the bottom of the paddle type dryer (shown in figures 2-7), the carrier gas dustproof distributor 20 comprises an upper part and a lower part, the upper part of the carrier gas dustproof distributor is a double-layer tubular jacket with the height of 400mm, the lower part of the carrier gas dustproof distributor is a horizontal tank body collecting tank 27 with the diameter of 200mm and the length of 400mm; the collection tank 27 is provided with a carrier gas inlet 30 and a discharge port 29 connected to the outside of the paddle dryer;
the double-layer pipe type jacket comprises an inner pipe 25, an outer pipe 24 and an interlayer formed between the two pipes, the interlayer and the upper end of the inner pipe are sealed, and the lower end of the interlayer is communicated with the collecting tank;
the interlayer is arranged at a position 10mm away from the collecting tank, an annular baffle 23 is horizontally arranged along the annular gap, one end of the annular baffle 23 is fixedly connected to the inner pipe wall, the other end of the annular baffle 23 can rotate downwards along the outer pipe wall, the annular baffle 23 is limited by a supporting rod 28, and the downward rotation angle of the annular baffle 23 is controlled to be less than 45 degrees; the inner pipe 25 is provided with inner layer distribution holes 21 above the annular baffle 23, and the outer pipe 24 is provided with outer layer distribution holes 22 above the annular baffle 23.
Polycarbonate powder product test methods:
water content test in polycarbonate: 1.5g of powder is taken, and the weighing mass is accurately recorded. The powder is filled into a special bottle of a Karl-type furnace, and a bottle cap is pressed tightly, and the Karl-type furnace is connected with a coulometric method moisture meter. The heating treatment temperature of the Karl-kiln is set to be 120 ℃, and the sample mass is accurately input to measure the water content after blank measurement.
Determination of the methylene chloride content in polycarbonate: and taking 7.0g of the powder in a 20ml glass bottle, and accurately recording the mass of the sample. Thereafter, methanol was added to a glass vial to 15.0g and the dilution factor was accurately recorded. And covering a bottle cap, carrying out ultrasonic treatment for ten minutes, and standing for 24 hours. Thereafter, the liquid in the bottle was aspirated with a disposable syringe and filtered into a 1.5ml gas vial for gas chromatography detection. Quantification was performed using an external standard curve.
Determination of the hydrogen chloride content in the polycarbonate: taking 4.0g of powder in a 50ml disposable centrifuge tube, accurately transferring 15ml of dichloromethane by using a liquid transfer gun, and standing. After the powder is completely dissolved, a pipette is used to accurately pipette 25ml of pure water into the centrifuge tube. Shaking thoroughly, shaking for 10min, standing for layering, sucking upper water phase with disposable syringe, filtering, detecting chloride ion content by ion chromatography, and performing blank dichloromethane extraction test.
And (3) polycarbonate color number determination: taking 2kg of polycarbonate powder, drying at 140 ℃ for 4h, preparing sample pieces by adopting a continuous injection molding machine, heating the first 9 pieces at 200 ℃, keeping no stay in the injection molding machine, keeping 10-14 pieces in the injection molding machine for 10min, and putting the sample pieces into a colorimeter to read the color numbers.
In the following examples, the process flow used in the present invention is shown in FIG. 1.
Example 1
Crude polycarbonate powder, which contains 10% moisture and 20% methylene chloride and has a particle size distribution of 10 to 1000. Mu.m, wherein the content of particles having a particle size of <100 μm is 8% by weight and the color number YI 1.55.
1) crude polycarbonate powder enters a fluidized bed dryer from the top at the rate of 5000kg/h for drying, and simultaneously high-temperature carrier gas is introduced, wherein the flow rate of the high-temperature carrier gas from a paddle dryer in the subsequent step 2) and an exhaust carrier gas from a shell and tube dryer in the step 3) is 5000Nm 3 The temperature is 140 ℃, the crude polycarbonate powder and high-temperature gas are in countercurrent contact for drying, the drying temperature is 140 ℃, and the retention time is about 1h; then the gas phase discharged from the top enters a cyclone separator, the polycarbonate powder with the grain diameter of more than or equal to 100 mu m is recovered by cyclone separation and returned to a fluidized bed dryer, the gas phase after cyclone separation is captured by a fine powder capturing tower, and then returned to the front-end procedure for re-dissolution and recovery, and the residual gas phase after capturing is sent to a gas recovery system; the polycarbonate powder discharged from the bottom contained 10% of methylene chloride, 4% of water and 1.5ppm of hydrogen chloride;
in step 1), the separation efficiency of polycarbonate powder with a particle size of less than 100 μm is 62%; polycarbonate powder discharged from the bottom of the fluidized bed dryer, wherein the content of particles having a particle size of <100 μm is less than 3% by weight.
2) The polycarbonate powder treated in the step 1) enters a paddle type dryer from the upper part for drying, and high-temperature nitrogen at the temperature of 140 ℃ is dried at 4000Nm 3 Introducing carrier gas serving as carrier gas and a heat source from a carrier gas inlet of a carrier gas dustproof distributor positioned at the bottom, firstly introducing high-temperature carrier gas into a collecting tank through the carrier gas inlet, then upwards introducing the high-temperature carrier gas into an inner pipe, sequentially passing through an inner layer distribution hole and an outer layer distribution hole, introducing the high-temperature carrier gas into a paddle type dryer, simultaneously dispersing polycarbonate powder in the paddle dryer, contacting the polycarbonate powder with the carrier gas dustproof distributor, wherein small particles with the particle size of 50-200 mu m enter an interlayer through the outer layer distribution hole, and then passing through the interlayerThe annular baffle is collected in a collection tank and recovered through a discharge opening. Diluting with high-temperature nitrogen and timely carrying out water volatilized from powder, dichloromethane and hydrogen chloride generated by dichloromethane decomposition, wherein the temperature in the drying process is 140 ℃, the retention time is about 1h, the waste carrier gas at the outlet is used as the carrier gas at the inlet of the fluidized bed dryer in the step 1), and the polycarbonate powder discharged by the paddle type dryer contains 2.5 percent of dichloromethane, 1 percent of water and 0.3ppm of hydrogen chloride;
the bottom of the paddle type dryer adopts 10 carrier gas dustproof distributors, the inner diameter of each distributor is 20mm, and the width of each interlayer is 1mm. The aperture of the inner layer distribution holes is 0.05mm, the total area of the open holes in unit area is 10%, the aperture of the outer layer distribution holes is 0.1mm, and the total area of the open holes in unit area is 20%.
In the step 2), the separation efficiency of the polycarbonate powder with the particle size of less than 100 μm is 95%; polycarbonate powder discharged therefrom, wherein the content of particles with a particle size of <100 μm is less than 0.14 wt.%.
3) The polycarbonate powder treated in the step 2) enters a tubular drier for drying, and simultaneously 2000Nm 3 Introducing high-temperature air with the temperature of 140 ℃ as a carrier gas and a heat source, wherein the temperature in the drying process is 120 ℃, the retention time is about 10h, and the waste carrier gas at the outlet is used as the carrier gas at the inlet of the fluidized bed dryer in the step 1) and is discharged from the outlet to obtain polycarbonate powder with stable color, wherein the polycarbonate powder comprises 200ppm of dichloromethane, 200ppm of water, 0.1ppm of hydrogen chloride and the color number (YI: 1.60).
Example 2
The crude polycarbonate powder produced in the preceding step, which contains 20% of water and 30% of methylene chloride, has a particle size distribution of 10 to 1000. Mu.m, wherein the content of particles having a particle size of <100 μm is 10wt%, and has a color number YI of 1.55.
1) crude polycarbonate powder enters a fluidized bed dryer from the top for drying at 5000kg/h, and simultaneously high-temperature carrier gas is introduced, wherein the flow rate of the high-temperature carrier gas from a paddle dryer in the subsequent step 2) and a shell-and-tube dryer in the step 3) is 15000Nm 3 At 110 deg.C, the crude polycarbonate powder is dried by countercurrent contact with high-temperature gas at 120 deg.C for a residence time of about0.1h; then the gas phase discharged from the top enters a cyclone separator, polycarbonate powder with the grain diameter of more than or equal to 100 mu m is recovered through cyclone separation and returned to a fluidized bed dryer, the gas phase after cyclone separation is captured by a fine powder capturing tower, and then the gas phase returns to the front-end process for re-dissolution and recovery, and the residual gas phase after capturing is sent to a gas recovery system; polycarbonate powder discharged from the bottom, the composition of which comprises 10wt% of methylene chloride, 12wt% of water and 0.8wt% of hydrogen chloride;
in step 1), the separation efficiency of polycarbonate powder with a particle size of less than 100 μm is 70%; polycarbonate powder discharged from the bottom of the fluidized bed dryer, wherein the content of particles having a particle size of <100 μm is less than 3%.
2) The polycarbonate powder treated in the step 1) enters a paddle type dryer from the upper part for drying, and meanwhile, high-temperature nitrogen gas with the temperature of 110 ℃ is dried in 10000Nm 3 And h, introducing a carrier gas inlet of a carrier gas dustproof distributor positioned at the bottom to serve as a carrier gas and a heat source, introducing a high-temperature carrier gas into a collecting tank through the carrier gas inlet, then upwards introducing the high-temperature carrier gas into an inner pipe, sequentially passing through an inner layer distribution hole and an outer layer distribution hole, introducing the high-temperature carrier gas into a paddle type dryer, simultaneously dispersing polycarbonate powder in the paddle dryer, contacting the carrier gas dustproof distributor, wherein small particles with the particle size of 50-200 mu m enter an interlayer through the outer layer distribution hole, then collecting the small particles into a collecting tank through an annular baffle, and recovering the small particles through a discharge port. Diluting with high-temperature nitrogen, timely carrying out water volatilized from powder, dichloromethane and hydrogen chloride generated by dichloromethane decomposition, wherein the temperature in the drying process is 110 ℃, the retention time is about 2 hours, the waste carrier gas at the outlet is used as the inlet carrier gas of the fluidized bed dryer in the step 1), and the polycarbonate powder discharged by the paddle dryer contains 5wt% of dichloromethane, 2wt% of water and 0.2ppm of hydrogen chloride;
the bottom of the paddle type dryer adopts 10 carrier gas dustproof distributors, and the distributors are equidistantly distributed at the bottom of the dryer. The inner diameter of the distributor is 100mm, and the annular gap is 10mm. The inner layer has a pore diameter of 0.2mm, the opening density is 10% in terms of the total area of the openings per unit area, the outer layer has a pore diameter of 0.5mm, and the opening density is 20% in terms of the total area of the openings per unit area.
In the step 2), the separation efficiency of the polycarbonate powder with the particle size of less than 100 μm is 97%; polycarbonate powder discharged therefrom, wherein the content of particles with a particle size of <100 μm is less than 0.1 wt.%.
3) The polycarbonate powder treated in the step 2) enters a tubular drier for drying, and simultaneously the drying speed is 5000Nm 3 Introducing high-temperature nitrogen with the temperature of 110 ℃ as a carrier gas and a heat source, wherein the temperature in the drying process is 140 ℃, the retention time is about 5 hours, the waste carrier gas at the outlet is used as the carrier gas at the inlet of the fluidized bed dryer in the step 1), and the polycarbonate powder with stable color is obtained by discharging from the outlet, wherein the polycarbonate powder comprises 140ppm of dichloromethane, 180ppm of water, 0.1ppm of hydrogen chloride and the color number (YI: 1.60).
Example 3
The crude polycarbonate powder produced in the preceding step, which contains 15% of water and 25% of methylene chloride, has a particle size distribution of 10 to 1000. Mu.m, wherein the content of particles having a particle size of <100 μm is 10% by weight, and has a color number YI 1.55.
1) crude polycarbonate powder enters a fluidized bed dryer from the top for drying at 5000kg/h, and simultaneously high-temperature carrier gas is introduced, wherein the flow rate of the high-temperature carrier gas from a paddle dryer in the subsequent step 2) and a shell-and-tube dryer in the step 3) is 12500Nm 3 H, the temperature is 140 ℃, the crude polycarbonate powder and high-temperature gas are in countercurrent contact for drying, the drying temperature is 140 ℃, and the retention time is about 1h; then the gas phase discharged from the top enters a cyclone separator, polycarbonate powder with the grain diameter of more than or equal to 100 mu m is recovered through cyclone separation and returned to a fluidized bed dryer, the gas phase after cyclone separation is collected by a fine powder collecting tower, and then the gas phase returns to the front-end process for re-dissolution and recovery, and the residual gas phase after collection is sent to a gas recovery system; the polycarbonate powder discharged from the bottom contained 9% of methylene chloride, 6% of water and 1ppm of hydrogen chloride;
in step 1), the separation efficiency of polycarbonate powder with a particle size of less than 100 μm is 78%; polycarbonate powder discharged from the bottom of the fluidized bed dryer, wherein the content of particles having a particle size of <100 μm is less than 2.2% by weight.
2) The polycarbonate powder treated in the step 1) enters the paddle from the upper partDrying with a leaf dryer while using high temperature nitrogen at 140 deg.C in a range of 7500Nm 3 And h, introducing a carrier gas inlet of a carrier gas dustproof distributor positioned at the bottom to serve as a carrier gas and a heat source, introducing a high-temperature carrier gas into a collecting tank through the carrier gas inlet, then upwards introducing the high-temperature carrier gas into an inner pipe, sequentially passing through an inner layer distribution hole and an outer layer distribution hole, introducing the high-temperature carrier gas into a paddle type dryer, simultaneously dispersing polycarbonate powder in the paddle dryer, contacting the carrier gas dustproof distributor, wherein small particles with the particle size of 50-200 mu m enter an interlayer through the outer layer distribution hole, then collecting the small particles into a collecting tank through an annular baffle, and recovering the small particles through a discharge port. Diluting with high-temperature nitrogen and timely carrying out water volatilized from powder, dichloromethane and hydrogen chloride generated by dichloromethane decomposition, wherein the temperature in the drying process is 140 ℃, the retention time is about 1h, the waste carrier gas at the outlet is used as the carrier gas at the inlet of the fluidized bed dryer in the step 1), and the polycarbonate powder discharged by the paddle type dryer contains 3wt% of dichloromethane, 2wt% of water and 0.1ppm of hydrogen chloride;
5 distributors are adopted and are equidistantly distributed at the bottom of the dryer. The inner diameter of the distributor is 100mm, and the width of the interlayer is 5mm. The inner layer has a pore diameter of 0.05mm, the opening density is 20% in terms of the total area of the openings in unit area, the outer layer has a pore diameter of 0.5mm, and the opening density is 30% in terms of the total area of the openings in unit area.
In step 2), the separation efficiency of polycarbonate powder with a particle size of less than 100 μm is 93%; the polycarbonate powder discharged therefrom has a content of <100 μm particle size of less than 0.14 wt.%.
3) The polycarbonate powder treated in the step 2) enters a tubular drier for drying, and simultaneously the drying speed is 5000Nm 3 Introducing high-temperature nitrogen with the temperature of 160 ℃ as a carrier gas and a heat source, wherein the temperature in the drying process is 120 ℃, the retention time is about 10 hours, the waste carrier gas at the outlet is used as the carrier gas at the inlet of the fluidized bed dryer in the step 1), and the polycarbonate powder with stable color is obtained by discharging from the outlet, wherein the polycarbonate powder comprises 120ppm of dichloromethane, 100ppm of water, 0.1ppm of hydrogen chloride and the color number (YI: 1.56).
Example 4
The crude polycarbonate powder produced in the preceding step, which contains 20% water and 20% methylene chloride, has a particle size distribution of 10 to 1000. Mu.m, wherein the content of particles having a particle size of <100 μm is 5wt%, and a color number YI of 1.55.
1) crude polycarbonate powder enters a fluidized bed dryer from the top for drying at 5000kg/h, and simultaneously high-temperature carrier gas is introduced, wherein the flow rate of the high-temperature carrier gas from a paddle dryer in the subsequent step 2) and a shell-and-tube dryer in the step 3) is 15000Nm 3 The temperature is 100 ℃, the crude polycarbonate powder and high-temperature gas are in countercurrent contact for drying, the drying temperature is 100 ℃, and the retention time is about 0.3h; then the gas phase discharged from the top enters a cyclone separator, polycarbonate powder with the grain diameter of more than or equal to 100 mu m is recovered through cyclone separation and returned to a fluidized bed dryer, the gas phase after cyclone separation is collected by a fine powder collecting tower, and then the gas phase returns to the front-end process for re-dissolution and recovery, and the residual gas phase after collection is sent to a gas recovery system; polycarbonate powder discharged from the bottom, the composition of which contained 13wt% of methylene chloride, 14wt% of water and 1ppm of hydrogen chloride;
in step 1), the separation efficiency of polycarbonate powder with a particle size of less than 100 μm is 73%; polycarbonate powder discharged from the bottom of the fluidized bed dryer, wherein the content of particles with a particle size of <100 μm is less than 1.4%.
2) The polycarbonate powder treated in the step 1) enters a paddle type dryer from the upper part for drying, and meanwhile, high-temperature nitrogen at the temperature of 100 ℃ is dried in 10000Nm 3 And h, introducing a carrier gas inlet of a carrier gas dustproof distributor positioned at the bottom to serve as a carrier gas and a heat source, introducing a high-temperature carrier gas into a collecting tank through the carrier gas inlet, then upwards introducing the high-temperature carrier gas into an inner pipe, sequentially passing through an inner layer distribution hole and an outer layer distribution hole, introducing the high-temperature carrier gas into a paddle type dryer, simultaneously dispersing polycarbonate powder in the paddle dryer, contacting the carrier gas dustproof distributor, wherein small particles with the particle size of 50-200 mu m enter an interlayer through the outer layer distribution hole, then collecting the small particles into a collecting tank through an annular baffle, and recovering the small particles through a discharge port. Diluting with high-temperature nitrogen and timely carrying out water volatilized from powder, dichloromethane and hydrogen chloride generated by dichloromethane decomposition, wherein the temperature in the drying process is 140 ℃, the retention time is about 4 hours, and the waste carrier gas at the outlet is used as the fluidized bed drying in the step 1)The inlet carrier gas of the dryer comprises 1.3wt% of methylene dichloride, 1.4wt% of water and 0.2ppm of hydrogen chloride, wherein the polycarbonate powder discharged by the paddle dryer comprises the components of 1.3wt% of methylene dichloride;
1 distributor is adopted and is equidistantly distributed at the bottom of the dryer. The inner diameter of the distributor is 100mm, and the annular gap is 5mm. The inner layer has a pore diameter of 0.05mm, the opening density is 15% by the total area of the openings in unit area, the outer layer has a pore diameter of 0.2mm, and the opening density is 25% by the total area of the openings in unit area.
In the step 2), the separation efficiency of the polycarbonate powder with the particle size of less than 100 μm is 85%; polycarbonate powder discharged therefrom, wherein the content of particles with a particle size of <100 μm is less than 0.14 wt.%.
3) The polycarbonate powder treated in the step 2) enters a tubular drier for drying, and the drying speed is 5000Nm 3 The high-temperature nitrogen with the temperature of 100 ℃ is introduced as a carrier gas and a heat source, the temperature in the drying process is 120 ℃, the retention time is about 10 hours, the waste carrier gas at the outlet is used as the carrier gas at the inlet of the fluidized bed dryer in the step 1), and the polycarbonate powder with stable color is obtained by discharging from the outlet, wherein the polycarbonate powder comprises 200ppm of dichloromethane, 180ppm of water, 0.1ppm of hydrogen chloride and the color number (YI: 1.58).
Example 5
The crude polycarbonate powder produced in the preceding step, which contains 20% of water and 20% of methylene chloride, has a particle size distribution of 10 to 1000. Mu.m, wherein the content of particles having a particle size of < 100. Mu.m is 5wt%, and has a color number YI of 1.55.
1) crude polycarbonate powder enters a fluidized bed dryer from the top for drying at 5000kg/h, and simultaneously high-temperature carrier gas is introduced, wherein the flow rate of the high-temperature carrier gas from a paddle dryer in the subsequent step 2) and a shell-and-tube dryer in the step 3) is 15000Nm 3 H, the temperature is 120 ℃, the crude polycarbonate powder and high-temperature gas are in countercurrent contact for drying, the drying temperature is 120 ℃, and the retention time is about 0.3h; then the gas phase discharged from the top enters a cyclone separator, the polycarbonate powder with the grain diameter of more than or equal to 100 mu m is recovered by cyclone separation and returned to a fluidized bed dryer, the gas phase after cyclone separation is collected by a fine powder collecting tower, and then the gas phase returns to the front-end working procedure to be re-dissolved and returned to the front-end working procedureCollecting, and sending the residual gas phase after trapping into a gas recovery system; the polycarbonate powder discharged from the bottom contained 9wt% of methylene chloride, 10wt% of water and 0.3ppm of hydrogen chloride;
in step 1), the separation efficiency of polycarbonate powder with a particle size of less than 100 μm is 76%; polycarbonate powder discharged from the bottom of the fluidized bed dryer, wherein the content of particles having a particle size of <100 μm is less than 1.2% by weight.
2) The polycarbonate powder treated in the step 1) enters a paddle type dryer from the upper part for drying, and meanwhile, high-temperature nitrogen at the temperature of 120 ℃ is dried in 10000Nm 3 Introducing the carrier gas serving as a carrier gas and a heat source from a carrier gas inlet of a carrier gas dustproof distributor positioned at the bottom, introducing high-temperature carrier gas into a collecting tank through the carrier gas inlet, then upwards introducing the high-temperature carrier gas into an inner pipe, sequentially passing through inner-layer distribution holes and outer-layer distribution holes, introducing the high-temperature carrier gas into a paddle type dryer, simultaneously contacting polycarbonate powder dispersed in the paddle dryer with the carrier gas dustproof distributor, wherein small particles with the particle size of 50-200 mu m enter an interlayer through the outer-layer distribution holes, then collecting the small particles into a collecting tank through an annular baffle, and recovering the small particles through a discharge opening. Diluting with high-temperature nitrogen, timely carrying out water volatilized from powder, dichloromethane and hydrogen chloride generated by dichloromethane decomposition, wherein the temperature in the drying process is 120 ℃, the retention time is about 3h, the waste carrier gas at the outlet is used as the inlet carrier gas of the fluidized bed dryer in the step 1), and the polycarbonate powder discharged by the paddle type dryer contains 1.7wt% of dichloromethane, 2wt% of water and 0.1ppm of hydrogen chloride;
5 distributors are adopted and are equidistantly distributed at the bottom of the dryer. The inner diameter of the distributor is 40mm, and the annular gap is 1mm. The inner layer has a pore diameter of 0.05mm, the opening density is 15% by the total area of the openings in unit area, the outer layer has a pore diameter of 0.2mm, and the opening density is 25% by the total area of the openings in unit area.
In step 2), the separation efficiency of the polycarbonate powder with the particle size of less than 100 μm is 95%; the polycarbonate powder discharged therefrom has a content of <100 μm particle size of less than 0.05% by weight.
3) The polycarbonate powder treated in the step 2) enters a tubular drier for drying, and simultaneously the drying speed is 5000Nm 3 'Haitong' medicine for treating rheumatismHigh-temperature nitrogen with the temperature of 120 ℃ is used as a carrier gas and a heat source, the temperature in the drying process is 140 ℃, the retention time is about 8 hours, the waste carrier gas at the outlet is used as the carrier gas at the inlet of the fluidized bed dryer in the step 1), and the polycarbonate powder with stable color is obtained by discharging from the outlet, wherein the polycarbonate powder comprises 70ppm of dichloromethane, 100ppm of water, 0.1ppm of hydrogen chloride and the color number (YI: 1.58).
Example 6
The crude polycarbonate powder produced in the preceding step, which contains 20% water and 20% methylene chloride, has a particle size distribution of 10 to 1000. Mu.m, wherein the content of particles having a particle size of <100 μm is 5wt%, and a color number YI of 1.55.
1) crude polycarbonate powder enters a fluidized bed dryer from the top at 5000kg/h for drying, and simultaneously high-temperature carrier gas is introduced, wherein the high-temperature gas comes from the subsequent paddle type dryer in the step 2) and the waste carrier gas in the tube type dryer in the step 3), and the carrier gas flow rate is 15000Nm 3 H, the temperature is 120 ℃, the crude polycarbonate powder and high-temperature gas are in countercurrent contact for drying, the drying temperature is 120 ℃, and the retention time is about 3h; then the gas phase discharged from the top enters a cyclone separator, polycarbonate powder with the grain diameter of more than or equal to 100 mu m is recovered through cyclone separation and returned to a fluidized bed dryer, the gas phase after cyclone separation is collected by a fine powder collecting tower, and then the gas phase returns to the front-end process for re-dissolution and recovery, and the residual gas phase after collection is sent to a gas recovery system; polycarbonate powder discharged from the bottom, the composition of which contained 5wt% of methylene chloride, 7wt% of water and 0.6ppm of hydrogen chloride;
in step 1), the separation efficiency of polycarbonate powder with a particle size of less than 100 μm is 76%; polycarbonate powder discharged from the bottom of the fluidized bed dryer, wherein the content of particles with a particle size of <100 μm is less than 1.2 wt.%.
2) The polycarbonate powder treated in the step 1) enters a paddle type dryer from the upper part for drying, and meanwhile, high-temperature nitrogen at the temperature of 120 ℃ is dried in 10000Nm 3 Introducing the carrier gas serving as the carrier gas and a heat source from a carrier gas inlet of a carrier gas dustproof distributor positioned at the bottom, wherein the high-temperature carrier gas firstly enters a collecting tank through the carrier gas inlet, then enters an inner pipe upwards, and enters the paddle through an inner layer distribution hole and an outer layer distribution hole in sequenceThe polycarbonate powder dispersed in the stirring paddle dryer in the blade dryer is contacted with a carrier gas dustproof distributor, wherein small particles with the particle size of 50-200 mu m enter the interlayer through outer layer distribution holes, are collected in a collection tank through an annular baffle and are recovered through a discharge opening. Diluting with high-temperature nitrogen, timely carrying out water volatilized from powder, dichloromethane and hydrogen chloride generated by dichloromethane decomposition, wherein the temperature in the drying process is 120 ℃, the retention time is about 3h, the waste carrier gas at the outlet is used as the inlet carrier gas of the fluidized bed dryer in the step 1), and the polycarbonate powder discharged by the paddle type dryer contains 1.7wt% of dichloromethane, 2wt% of water and 0.1ppm of hydrogen chloride;
5 distributors are adopted and are equidistantly distributed at the bottom of the dryer. The inner diameter of the distributor is 80mm, and the annular gap is 10mm. The inner layer has a pore diameter of 0.05mm, the opening density is 15% of the total opening area per unit area, the outer layer has a pore diameter of 0.1mm, and the opening density is 25% of the total opening area per unit area.
In the step 2), the separation efficiency of the polycarbonate powder with the particle size of less than 100 μm is 65%; the polycarbonate powder discharged therefrom has a content of less than 0.08% with a particle size of <100 μm.
3) The polycarbonate powder treated in the step 2) enters a tubular drier for drying, and the drying speed is 5000Nm 3 Introducing high-temperature nitrogen with the temperature of 120 ℃ as a carrier gas and a heat source, wherein the temperature in the drying process is 140 ℃, the retention time is about 8 hours, the waste carrier gas at the outlet is used as the carrier gas at the inlet of the fluidized bed dryer in the step 1), and the polycarbonate powder with stable color is obtained by discharging from the outlet, wherein the polycarbonate powder comprises 100ppm of dichloromethane, 100ppm of water, 0.1ppm of hydrogen chloride and the color number (YI: 1.55).
Comparative example 1
The difference from example 1 was that, except for not using step 2) and not installing a carrier gas dust-proof distributor at the bottom of the paddle dryer, the polycarbonate powder obtained was identical in composition with 400ppm of methylene chloride, 500ppm of water, 10ppm of hydrogen chloride, color number (YI: 2.69), and 2.9wt% of particles having a particle diameter of < 100. Mu.m.
Comparative example 2
The difference from example 1 was only that drying was not carried out in the fluidized bed dryer of step 1), but the polycarbonate powder obtained had a composition containing 500ppm of methylene chloride, 400ppm of water, 0.2ppm of hydrogen chloride, a color number (YI: 2.01) and a content of particles having a particle size of <100 μm of 0.48% by weight.
Comparative example 3
The difference from example 1 was only that, instead of using the paddle dryer of step 2), a polycarbonate powder having a composition comprising 1200ppm of methylene chloride, 700ppm of water, 20ppm of hydrogen chloride, a color number (YI: 2.6) and a particle content of 3.0 wt.% of particles having a particle diameter of <100 μm was obtained in the same manner.
Comparative example 4
The difference from example 1 is that the fluidized bed dryer of step 1) is not used for drying, and the blade dryer of step 2) is not provided with a carrier gas dustproof distributor at the bottom, and the operation is the same, the polycarbonate powder obtained contains 1600ppm of methylene dichloride, 900ppm of water, 35ppm of hydrogen chloride, color number (YI: 3.6) and 4.5wt% of particles with the particle diameter less than 100 μm.
Claims (30)
1. A method of preparing a color stable polycarbonate powder, comprising the steps of:
1) Drying the crude polycarbonate powder in a fluidized bed dryer, removing partial dichloromethane and water, and removing polycarbonate powder with the particle size of less than 100 mu m by a cyclone separator;
2) The polycarbonate powder treated in the step 1) enters a paddle type dryer for drying, and further dichloromethane, water and hydrogen chloride gas generated by decomposition of dichloromethane are removed;
3) And (3) drying the polycarbonate powder treated in the step 2) in a tubular dryer, and deeply removing dichloromethane and water to obtain the polycarbonate powder with stable color.
2. The process according to claim 1, wherein in step 1), the crude polycarbonate powder has a composition comprising, by mass, 10 to 20% of methylene chloride and 20 to 30% of water;
the coarse polycarbonate powder has a particle size distribution of 10 to 1000. Mu.m, wherein the content of particles having a particle size of <100 μm is 5 to 10 wt.%.
3. The method according to claim 1, wherein in the step 1), a high temperature gas is introduced as a carrier gas and a heat source, and the temperature of the high temperature gas is 100-140 ℃.
4. The production method according to claim 3, wherein the high-temperature gas temperature is 110 to 120 ℃.
5. The method according to claim 1, wherein the drying in step 1) is carried out at a temperature of 110 to 140 ℃ and a residence time of 0.1 to 5 hours.
6. The method of claim 5, wherein the drying is carried out at a temperature of 120 to 130 ℃ and a residence time of 0.3 to 1 hour.
7. The method according to claim 3, wherein the high-temperature gas is used in an amount of 1 to 3Nm in relation to the amount of the crude polycarbonate powder 3 /kg。
8. The process according to claim 7, wherein the high-temperature gas is used in an amount of 1.4 to 2Nm in relation to the raw polycarbonate powder 3 /kg。
9. The method of claim 3, wherein the high temperature gas is selected from the group consisting of hot air, hot nitrogen, spent carrier gas from step 2) paddle dryers and step 3) shell and tube dryers.
10. The method of claim 9, wherein the high temperature gas uses a waste carrier gas from the step 2) paddle dryer and the step 3) shell and tube dryer.
11. The process according to claim 3, wherein the crude polycarbonate powder is introduced into the fluidized bed dryer from the top, and is dried by countercurrent contact with a high-temperature gas, and then the gas phase discharged from the top is introduced into a cyclone separator, and the polycarbonate powder having a particle size of 100 μm or more entrained therein is recovered by cyclone separation and returned to the fluidized bed dryer, and the polycarbonate powder discharged from the bottom is introduced into the paddle dryer of step 2).
12. The process according to claim 11, wherein the gas phase after the cyclone separation is recovered by collecting the polycarbonate powder entrained in the gas phase by a fines collection column and then returned to the front-end process for redissolution and recovery.
13. The production method according to claim 12, wherein the fines capture column is a tray column.
14. The process according to claim 1, wherein in step 1), the removal efficiency of the polycarbonate powder having a particle size of <100 μm is 60% or more; polycarbonate powder discharged from the bottom of the fluidized bed dryer, wherein the content of particles with a size of <100 μm is less than 3 wt.%;
the polycarbonate powder discharged from the bottom of the fluidized bed dryer had a composition comprising, by mass, 5 to 13% of methylene chloride, 4 to 10% of water and 0.6 to 1.5ppm of hydrogen chloride.
15. The preparation method according to claim 1, wherein in the step 2), a high-temperature carrier gas is introduced during the drying process, and the temperature of the high-temperature carrier gas is 100-140 ℃.
16. The method of claim 15, wherein the high temperature carrier gas is selected from the group consisting of high temperature nitrogen, air.
17. The method according to claim 1, wherein in step 2), the drying is carried out at a temperature of 110 to 140 ℃ and a residence time of 1 to 4 hours.
18. The method of claim 17, wherein the drying is carried out at a temperature of 120-130 ℃ and a residence time of 2-3 hours.
19. The preparation method according to claim 1, characterized in that in step 2), a carrier gas dustproof distributor is arranged at the bottom of the paddle type dryer, and the number of the carrier gas dustproof distributors is 1-10;
the carrier gas dustproof distributor comprises an upper part and a lower part, wherein the upper part of the carrier gas dustproof distributor is provided with a double-layer tubular jacket, and the lower part of the carrier gas dustproof distributor is provided with a collecting tank; the collecting tank is also provided with a carrier gas inlet and a discharge port;
the double-layer tubular jacket comprises an inner tube, an outer tube and an interlayer formed between the two tubes;
the upper end of the interlayer is sealed, and the lower end of the interlayer is communicated with the collecting tank; the upper end of the inner pipe is sealed, and the lower end of the inner pipe is communicated with the collecting tank;
the interlayer is horizontally provided with an annular baffle along the annular gap at a height of 10-40mm from the collecting tank, one end of the annular baffle is fixedly connected to the inner pipe wall, the other end of the annular baffle can rotate downwards along the outer pipe wall, and the downward rotation angle of the annular baffle is controlled to be less than 45 degrees by adopting a support rod for limiting;
the inner pipe is provided with inner layer distribution holes above the annular baffle, the aperture of the inner layer distribution holes is 0.05-0.3mm, and the hole opening density is 10-20% of the total area of the holes in unit area; the outer pipe is provided with outer layer distribution holes above the annular baffle, the aperture of the outer layer distribution holes is 0.1-0.5mm, and the hole density is 20-30% of the total area of holes in unit area.
20. The method of claim 19, wherein the number of the carrier gas dust-proof distributors is 5 to 8.
21. The method of claim 19, wherein the carrier gas dust distributor is evenly distributed at the bottom of the paddle dryer.
22. The preparation method according to claim 19, wherein the double-tube jacket has a height of 100-400mm, the collection tank has a horizontal tank shape, a diameter of 200mm or more and a length of 400mm or more.
23. A method of making as set forth in claim 19 wherein the carrier gas inlet and discharge ports are connected to the exterior of the paddle dryer.
24. The method of claim 19, wherein the inner tube diameter is 20 to 100mm and the interlayer width is 1 to 10mm.
25. The process according to claim 1, wherein in step 2) the polycarbonate powder discharged from the paddle dryer has a content of particles with a diameter <100 μm of less than 0.14% by weight;
the polycarbonate powder discharged from the bottom of the paddle dryer comprises, by mass, 1 to 4.9% of methylene chloride, 1 to 3% of water, and 0.1 to 0.3ppm of hydrogen chloride.
26. The preparation method according to claim 1, wherein in the step 3), a high-temperature carrier gas is introduced during the drying process, the temperature of the high-temperature carrier gas is 100-140 ℃, and the high-temperature carrier gas is used as a heat source.
27. The method of claim 26, wherein the high temperature carrier gas is selected from the group consisting of high temperature nitrogen, air.
28. The method of claim 1, wherein in step 3), the drying is carried out at a temperature of 120 to 160 ℃ and a residence time of 2 to 10 hours.
29. The method of claim 28, wherein the drying is carried out at a temperature of 130 to 140 ℃ and a residence time of 5 to 8 hours.
30. The method of claim 1, wherein in step 3), the color-stable polycarbonate powder has a methylene chloride content of less than 200ppm, a water content of less than 200ppm, and a hydrochloric acid content of less than 0.1ppm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011454464.1A CN112595033B (en) | 2020-12-10 | 2020-12-10 | Preparation method of polycarbonate powder with stable color |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011454464.1A CN112595033B (en) | 2020-12-10 | 2020-12-10 | Preparation method of polycarbonate powder with stable color |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112595033A CN112595033A (en) | 2021-04-02 |
| CN112595033B true CN112595033B (en) | 2022-11-08 |
Family
ID=75192188
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011454464.1A Active CN112595033B (en) | 2020-12-10 | 2020-12-10 | Preparation method of polycarbonate powder with stable color |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112595033B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114644776B (en) * | 2022-04-29 | 2023-09-01 | 聊城鲁西聚碳酸酯有限公司 | System and method for recycling polycarbonate powder |
| CN115364977A (en) * | 2022-07-22 | 2022-11-22 | 深圳市德力塑化工科技有限公司 | Preparation method and application of polycarbonate powder |
Citations (22)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1451718A (en) * | 1973-04-07 | 1976-10-06 | Buettner Schilde Haas Ag | Heat treatment of granulates |
| JP2000239372A (en) * | 1999-02-23 | 2000-09-05 | Mitsubishi Gas Chem Co Inc | Method for drying polycarbonate resin for optics |
| JP2001294294A (en) * | 2000-04-12 | 2001-10-23 | Taizo Miyazaki | Drying apparatus |
| JP2003277513A (en) * | 2002-03-27 | 2003-10-02 | Mitsubishi Rayon Co Ltd | Method of manufacturing granular diene-based graft polymer |
| CN101605643A (en) * | 2006-12-11 | 2009-12-16 | 布勒公司 | Produce the method for homogeneously crystallized polycondensate pellets |
| CN101675092A (en) * | 2007-05-04 | 2010-03-17 | 贝林格尔英格海姆法玛两合公司 | Method and device for cleaning an absorptive polyester |
| CN101722588A (en) * | 2008-10-29 | 2010-06-09 | 株式会社技术高 | drying hopper |
| CN102620526A (en) * | 2012-03-16 | 2012-08-01 | 甘肃银光聚银化工有限公司 | Method for drying poly carbonate (PC) |
| CN102645085A (en) * | 2012-02-24 | 2012-08-22 | 青岛科技大学 | Method for continuously drying polycarbonate |
| CN103640108A (en) * | 2013-12-14 | 2014-03-19 | 甘肃银光聚银化工有限公司 | Method for drying polycarbonate |
| CN104697296A (en) * | 2015-02-16 | 2015-06-10 | 聊城鲁西聚碳酸酯有限公司 | Drying system of water-bearing polycarbonate sheet and drying technology |
| CN104910401A (en) * | 2015-04-17 | 2015-09-16 | 聊城鲁西聚碳酸酯有限公司 | Polycarbonate and solvent separation system, and method thereof |
| EP2921273A1 (en) * | 2014-03-19 | 2015-09-23 | SIMAR GmbH | Method and device for drying polymeric granules |
| CN106459425A (en) * | 2014-05-30 | 2017-02-22 | 出光兴产株式会社 | Method for producing polycarbonate |
| CN206094839U (en) * | 2016-09-30 | 2017-04-12 | 福建华塑新材料有限公司 | Polycarbonate combined material desiccator |
| WO2017218885A1 (en) * | 2016-06-16 | 2017-12-21 | DSV Holdings, LLC | Extruded polycarbonate sticker for spacing wood |
| CN107685404A (en) * | 2016-08-04 | 2018-02-13 | 天华化工机械及自动化研究设计院有限公司 | A kind of carbonic ester high molecular polymer two-stage contact drying system and its drying process |
| CN109996833A (en) * | 2016-11-16 | 2019-07-09 | 株式会社日本触媒 | The manufacturing method of absorbent resin powder and the drying device and drying means of graininess aqueous gel |
| CN111793343A (en) * | 2020-07-13 | 2020-10-20 | 万华化学集团股份有限公司 | Polycarbonate composition and preparation method thereof |
| CN112460921A (en) * | 2020-12-14 | 2021-03-09 | 天华化工机械及自动化研究设计院有限公司 | Closed circulating type polycarbonate flocculus deep drying and devolatilizing device and process |
| CN214792406U (en) * | 2021-05-11 | 2021-11-19 | 福建华塑新材料有限公司 | Polycarbonate composite material drying machine |
| CN215002550U (en) * | 2020-12-14 | 2021-12-03 | 天华化工机械及自动化研究设计院有限公司 | Closed circulating type polycarbonate flocculus deep drying and devolatilizing device |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5922826A (en) * | 1995-01-31 | 1999-07-13 | Idemitsu Kosan Co., Ltd. | Process for producing polycarbonate |
| CN100404989C (en) * | 2002-12-18 | 2008-07-23 | 兰州瑞德干燥技术有限公司 | Nitrogen-cycle engineering plastic air current and fluidized bed drying method |
| KR100702436B1 (en) * | 2004-11-06 | 2007-04-03 | 주식회사 엘지화학 | Process for preparing polycarbonate-co-siloxane using spray-crystallizing method |
| EP2256146A1 (en) * | 2009-05-30 | 2010-12-01 | Bayer MaterialScience AG | Extremely pure polycarbonate having good natural colour and thermal resistance and a device and method for production of same |
| CN102435049B (en) * | 2011-10-27 | 2014-12-31 | 西王药业有限公司 | Anhydrous dextrose drying device and drying process |
| CN105176039A (en) * | 2015-10-01 | 2015-12-23 | 常州市奥普泰科光电有限公司 | Preparation method of polycarbonate with high ultraviolet resistance |
| CN108413719A (en) * | 2018-03-26 | 2018-08-17 | 天华化工机械及自动化研究设计院有限公司 | A method of volatile matter in polypropylene powder is removed using vacuum blade dryer |
-
2020
- 2020-12-10 CN CN202011454464.1A patent/CN112595033B/en active Active
Patent Citations (22)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1451718A (en) * | 1973-04-07 | 1976-10-06 | Buettner Schilde Haas Ag | Heat treatment of granulates |
| JP2000239372A (en) * | 1999-02-23 | 2000-09-05 | Mitsubishi Gas Chem Co Inc | Method for drying polycarbonate resin for optics |
| JP2001294294A (en) * | 2000-04-12 | 2001-10-23 | Taizo Miyazaki | Drying apparatus |
| JP2003277513A (en) * | 2002-03-27 | 2003-10-02 | Mitsubishi Rayon Co Ltd | Method of manufacturing granular diene-based graft polymer |
| CN101605643A (en) * | 2006-12-11 | 2009-12-16 | 布勒公司 | Produce the method for homogeneously crystallized polycondensate pellets |
| CN101675092A (en) * | 2007-05-04 | 2010-03-17 | 贝林格尔英格海姆法玛两合公司 | Method and device for cleaning an absorptive polyester |
| CN101722588A (en) * | 2008-10-29 | 2010-06-09 | 株式会社技术高 | drying hopper |
| CN102645085A (en) * | 2012-02-24 | 2012-08-22 | 青岛科技大学 | Method for continuously drying polycarbonate |
| CN102620526A (en) * | 2012-03-16 | 2012-08-01 | 甘肃银光聚银化工有限公司 | Method for drying poly carbonate (PC) |
| CN103640108A (en) * | 2013-12-14 | 2014-03-19 | 甘肃银光聚银化工有限公司 | Method for drying polycarbonate |
| EP2921273A1 (en) * | 2014-03-19 | 2015-09-23 | SIMAR GmbH | Method and device for drying polymeric granules |
| CN106459425A (en) * | 2014-05-30 | 2017-02-22 | 出光兴产株式会社 | Method for producing polycarbonate |
| CN104697296A (en) * | 2015-02-16 | 2015-06-10 | 聊城鲁西聚碳酸酯有限公司 | Drying system of water-bearing polycarbonate sheet and drying technology |
| CN104910401A (en) * | 2015-04-17 | 2015-09-16 | 聊城鲁西聚碳酸酯有限公司 | Polycarbonate and solvent separation system, and method thereof |
| WO2017218885A1 (en) * | 2016-06-16 | 2017-12-21 | DSV Holdings, LLC | Extruded polycarbonate sticker for spacing wood |
| CN107685404A (en) * | 2016-08-04 | 2018-02-13 | 天华化工机械及自动化研究设计院有限公司 | A kind of carbonic ester high molecular polymer two-stage contact drying system and its drying process |
| CN206094839U (en) * | 2016-09-30 | 2017-04-12 | 福建华塑新材料有限公司 | Polycarbonate combined material desiccator |
| CN109996833A (en) * | 2016-11-16 | 2019-07-09 | 株式会社日本触媒 | The manufacturing method of absorbent resin powder and the drying device and drying means of graininess aqueous gel |
| CN111793343A (en) * | 2020-07-13 | 2020-10-20 | 万华化学集团股份有限公司 | Polycarbonate composition and preparation method thereof |
| CN112460921A (en) * | 2020-12-14 | 2021-03-09 | 天华化工机械及自动化研究设计院有限公司 | Closed circulating type polycarbonate flocculus deep drying and devolatilizing device and process |
| CN215002550U (en) * | 2020-12-14 | 2021-12-03 | 天华化工机械及自动化研究设计院有限公司 | Closed circulating type polycarbonate flocculus deep drying and devolatilizing device |
| CN214792406U (en) * | 2021-05-11 | 2021-11-19 | 福建华塑新材料有限公司 | Polycarbonate composite material drying machine |
Non-Patent Citations (1)
| Title |
|---|
| 气流干燥过程的数值模拟;张道斌;《中国优秀硕士学位论文全文数据库 (工程科技Ⅰ辑)》;20130630;全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112595033A (en) | 2021-04-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112595033B (en) | Preparation method of polycarbonate powder with stable color | |
| CN105329892B (en) | Method for producing capacitive carbon from rice husks | |
| CN104072419B (en) | The purification process of a kind of caprolactam and purification devices | |
| CN1012812B (en) | Method for recovering gallium | |
| CN111333046B (en) | Resource recovery method and system for waste lithium iron phosphate anode based on hydrochloric acid circulation | |
| CN107640780A (en) | A kind of preparation method of high-purity hydrogen aluminum oxide | |
| CN107601450A (en) | A kind of production technology of coal tar pitch MCMB | |
| CN110054186A (en) | A method of it producing capacitance carbon desiliconization Sewage treatment and utilizes | |
| CN101481365B (en) | Method for preparing epoxy chloropropane by using hydrochloric acid water solution of dichlorohydrin | |
| WO2013018959A1 (en) | Method for manufacturing clean fuel, and reactor for extracting and separating organic components therefor | |
| CN112902557A (en) | Environment-friendly continuous boiling drying unit and working method thereof | |
| CN113646318A (en) | Preparation method of organotin sucrose complex | |
| CN108299403A (en) | A kind of TGIC production methods being granulated based on molten steel band | |
| CN209685657U (en) | A kind of polymer purification separation integrated device | |
| CN106955680A (en) | One kind oil refining spent bleaching clay continuous regeneration method | |
| CN207933043U (en) | The three aluminum hydride preparation systems with solvent recovery | |
| CN103318958B (en) | Separation and refining method of arsenic trioxide | |
| CN211864177U (en) | Phenolic resin sheet-pulling machine waste gas collection processing apparatus | |
| CN113856369A (en) | Efficient energy-saving washing and dedusting method for organic silicon monomer synthesis gas | |
| CN113651343A (en) | Method for preparing high-purity lithium carbonate by recycling lithium hydroxide for air purification | |
| CN113620320B (en) | Process for preparing high-purity lithium carbonate by adopting continuous carbonization method | |
| CN105504348B (en) | There are environmental benefit bead shaped particle shape antioxidant 1010 and its preparation method and application | |
| CN100998956A (en) | Recovery and apptied mechanically method of phase transfer catalyst | |
| CN105777550B (en) | The method that one kind being continuously synthesizing to 2,4- dinitroanisol | |
| CN1055680C (en) | Preparation of cyanuric chloride by gas-phase one-stage method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |