Isocyanuric acid triglycidyl ester melt granulation production system and production method

Abstract

This invention relates to a melt granulation production system and method for triglycidyl isocyanurate (TGIC), belonging to the field of TGIC granulation technology. It solves the technical problems of high volatile residue and large dust content in the extrusion granulation process for TGIC granules, and the cumbersome process, high safety risks, immature technology, and unstable product quality in the melt granulation process for TGIC granules. The production system of this invention includes a melting kettle, a temporary storage kettle, a thin-film evaporator, a crystallizer, a feeder, and a steel belt granulator. This invention also provides a method for producing triglycidyl isocyanurate (TGIC) granules using this production system. This melt granulation production system and method are highly efficient, have good continuity, good safety, and produce TGIC granules that are free of powder, have stable and uniform quality, and high reliability.

Description

Technical Field

[0001] This invention belongs to the field of triglycidyl isocyanurate granulation technology, specifically relating to a melt granulation production system and method for triglycidyl isocyanurate (TGIC). Background Technology

[0002] Triglycidyl isocyanurate (TGIC), chemically known as (1H,3H,5H)-tris(2,3-epoxypropyl)-triazine-2,4,6-trione, is a high-performance curing agent. Due to its three epoxy groups and triazine ring structure, TGIC forms coatings with excellent heat resistance, weather resistance, chemical resistance, and high-temperature resistance when cross-linked and cured with acids or anhydrides. It is widely used in powder coatings, electronic inks, and packaging.

[0003] In existing technologies, the production methods of TGIC typically include steps such as synthesis, distillation, crystallization, wet extrusion granulation, and drying. Among these, wet powder extrusion granulation is a granulation method that uses physical extrusion, which easily leads to solvent residue, resulting in a long drying process. Furthermore, because the produced TGIC particles have insufficient strength, there is significant powder shedding during transportation and use, causing a large amount of dust.

[0004] To reduce dust and solvent residue in TGIC particles, melt granulation has been proposed for their production in recent years. For example, Chinese patent 101773806A discloses a melt granulation process and production line for triglycidyl isocyanate (TGIC). This process involves distilling the material in a distillation vessel at different temperatures under both atmospheric and vacuum conditions. After all the organic solvent has evaporated, the material is evenly transferred to a belt cooling conveyor for cooling and pulverization. However, this process still cannot effectively reduce solvent residue in the product, and the product still requires further crushing after passing through the belt cooler, making the process complex. Fine powder is still generated during crushing, and the particle size is uneven. For example, a Chinese patent discloses a production line and process for extruding and granulating dry powder of triglycidyl isocyanurate (publication number 103896929A). This granulation production line includes a vibrating dryer with a material inlet, a material outlet, and a gas outlet. The gas outlet of the vibrating dryer is connected to the inlet of a condenser, and the outlet of the condenser is sequentially connected to a solvent recovery tank and a gas induced draft fan I. The material outlet of the vibrating dryer is connected to the inlet of a dry powder cyclone separator via a conveying pipeline. A vent valve and a discharge valve are provided on the conveying pipeline. The bottom valve of the dry powder cyclone separator has coarse and fine powder outlets. The coarse powder outlet is connected to one inlet of the dry powder tank, and the fine powder outlet is connected to a bag filter. One end of the bag filter is connected to the induced draft fan II, and the other end is connected to the other inlet of the dry powder tank. The outlet of the dry powder tank is connected in sequence to the material extruder, tablet press, belt cooling conveyor, crusher, screening machine, and packaging machine. The inlet and outlet of the condenser are connected to the cooling water pipeline, and the jacket of the vibrating dryer is connected to the steam pipeline. However, this granulation production line uses TGIC wet materials dried into dry powder raw materials, resulting in a large amount of dust and a poor working environment. Similarly, the melt-granulated products require crushing and screening processes, which also generate dust and uneven particle size. Moreover, the process is cumbersome and energy-intensive. For example, a Chinese patent discloses a method for producing TGIC by granulation of molten steel strip (publication number 108299403A). This method involves adding epichlorohydrin, cyanuric acid, and tetramethylammonium chloride catalyst to a reaction vessel, heating and carrying out a synthesis reaction under normal pressure to obtain an intermediate product, then adding a solid alkali to carry out a cyclization reaction; filtering and allowing the cyclization reaction product to stand and separate into layers, heating and distilling the lower organic phase under reduced pressure; crystallizing and centrifuging the distilled material to obtain TGIC crystals containing volatile organic compounds; placing the TGIC crystals containing volatile organic compounds in a vacuum environment and heating them to obtain molten TGIC; dripping them onto a pre-cooled steel strip granulator, where the TGIC rapidly cools to form hard TGIC particles that are not prone to dust generation.However, this production method uses TGIC material containing methanol as the main volatile substance to remove solvent through heating and depressurization distillation. Because TGIC is a heat-sensitive substance, a large amount of molten material is prone to carbonization under prolonged high temperature, posing a safety risk. Furthermore, TGIC crystals containing volatile organic compounds are placed in a vacuum environment and heated in a single melting vessel, resulting in a thick accumulation of material. Only low-boiling-point volatile solvents can be removed, leading to high ECH residue in the product and substandard quality. For example, a Chinese patent discloses an integrated processing method for efficient TGIC devolatilization and melt extrusion granulation (publication number 114130303A). This processing method melts wet TGIC powder in a twin-screw extruder. The molten TGIC is conveyed to the outlet of the twin-screw extruder under the action of the twin screws. The melt is uniformly shaped into spherical liquids by the feeder head and drips onto the forming steel belt to form TGIC granules. Although this process can achieve dust-free preparation of granular TGIC, it is limited by the fact that the equipment is a vacuum system. The vacuum is unstable, the removal of solvent residue is unstable and incomplete, and the product quality is unstable. In addition, this processing method requires the input of TGIC powder seed crystals that do not contain epichlorohydrin and methanol, the product forming process is time-consuming, resulting in large equipment investment and low production efficiency.

[0005] In summary, the existing methods for preparing TGIC particles using melt granulation have several technical problems, including cumbersome procedures, high process safety risks, immature technology, and unstable product quality. Summary of the Invention

[0006] In view of this, in order to solve the technical problems of high volatile residue and large dust content in the extrusion granulation process for preparing TGIC particles, and the cumbersome process, high process safety risk, immature technology and unstable product quality in the melt granulation process for preparing TGIC particles, the present invention provides a melt granulation production system and method for triglycidyl isocyanurate.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows.

[0008] This invention provides a melt granulation production system for triglycidyl isocyanurate, comprising a melting kettle, a temporary storage kettle, a thin-film evaporator, a crystallizer, a distributor, and a steel strip granulator. The outlet of the melting kettle is connected to the inlet of the temporary storage kettle via a first pipe, the outlet of the temporary storage kettle is connected to the inlet of the thin-film evaporator via a second pipe, the outlet of the thin-film evaporator is connected to the inlet of a third melt pump via a third pipe, the outlet of the third melt pump is connected to the inlet of the crystallizer via a fourth pipe, the outlet of the crystallizer is connected to the inlet of the third melt pump via a fifth pipe, and the outlet of the crystallizer is connected to the inlet of the distributor via a sixth pipe. The steel strip granulator is located below the outlet of the distributor.

[0009] Preferably, the first pipeline is equipped with a first melt pump, the second pipeline is equipped with a second melt pump, and the sixth pipeline is equipped with a fourth melt pump.

[0010] Preferably, valves are provided on the first, second, third, and sixth pipes.

[0011] Preferably, the sixth pipeline is equipped with a digital remote pressure gauge.

[0012] Preferably, the production system further includes a first condenser and a first collection tank. One end of the first condenser is connected to the melting vessel, and the other end is connected to the first collection tank. The first condenser can condense the methanol volatilized in the melting vessel and store it in the first collection tank.

[0013] Preferably, the production system further includes a second condenser and a second collection tank. One end of the second condenser is connected to the thin-film evaporator, and the other end is connected to the second collection tank. The second condenser can condense the epichlorohydrin volatilized in the thin-film evaporator and store it in the second collection tank.

[0014] This invention also provides a method for producing triglycidyl isocyanurate by melt granulation, comprising the following steps:

[0015] Step 1: Add the wet powder of methanol-containing triglycidyl isocyanurate to the melting vessel;

[0016] Step 2: After holding the methanol-containing triglycidyl isocyanurate wet powder at 65-90℃ for 60-90 min, remove the methanol by distillation, and transfer the resulting molten material to a temporary storage vessel.

[0017] Step 3: First, preheat the thin film evaporator to 105-130℃ and control the pressure at -0.095--0.1 MPa. Then, continuously transfer the molten material in the temporary storage vessel to the thin film evaporator and remove epichlorohydrin under reduced pressure to obtain a transparent melt material.

[0018] Step 4: The transparent melt material is transported to the crystallizer through the third melt pump and held at 95-105℃ for 20-30 minutes. At the same time, the third melt pump pushes the transparent melt material in the crystallizer to circulate and cool it down to 80-95℃ at a cooling rate of 0.3-0.5℃ / min, controlling the light transmittance at 15-35%, to obtain the crystallized material.

[0019] Step 5: The crystalline material is conveyed to the distributor, and the pressure of the crystalline material is controlled at 0.15-0.45 MPa. The crystalline material is evenly dripped onto the steel belt granulator, cooled and shaped to obtain triglycidyl isocyanurate granules.

[0020] The temperature of the steel strip granulator gradually decreases along the direction of movement of the crystalline material, and the temperature range is 15 to 80°C.

[0021] Preferably, in step one, the methanol-containing triglycidyl isocyanurate wet powder is obtained as follows: cyanuric acid, epichlorohydrin, and the catalyst benzyltriethylammonium chloride are added to a reaction vessel at a mass ratio of 1:10-15:0.02-0.06, and heated to 100-110°C under normal pressure for a synthesis reaction. Then, caustic soda is added at a mass ratio of cyanuric acid to caustic soda of 1:1-1.3, and a cyclization reaction is carried out at 15-25°C. The obtained cyclization reaction product is filtered and separated into layers. The lower organic phase is distilled to recover epichlorohydrin, and the distilled material is crystallized with methanol, centrifuged, and the methanol-containing triglycidyl isocyanurate wet powder is added to a melting vessel.

[0022] Preferably, in step two, the temperature is maintained at 70–80°C for 60–90 minutes.

[0023] Preferably, in step two, the methanol removed by distillation is condensed in the first condenser and collected in the first collection tank.

[0024] Preferably, step two is carried out under stirring at a speed of 40-60 rpm.

[0025] Preferably, in step three, the preheating temperature is 110–120°C.

[0026] Preferably, in step three, the epichlorohydrin removed under reduced pressure is condensed in a second condenser and collected in a second collection tank.

[0027] Preferably, in step four, the crystallizer is supplied with circulating cooling water, and the flow rate of the cooling water is controlled by a valve.

[0028] Preferably, in step four, the stirring speed of the crystallizer is 15 to 30 rpm.

[0029] Preferably, in step four, the temperature is maintained at 95–100°C and then cooled to 83–90°C.

[0030] Preferably, in step four, the light transmittance is controlled to be between 20% and 30%.

[0031] Preferably, in step four, the self-circulation speed of the transparent melt material pushed by the third melt pump into the crystallizer is 30-60 L / min.

[0032] Preferably, in step five, the crystalline material is transported to the distributor by a fourth melt pump, the discharge rate of the fourth melt pump is 30-45 L / min, and the crystalline material is evenly dripped onto the steel strip granulator.

[0033] Preferably, in step five, taking the dripping point of the crystalline material as the starting point, the cooling temperature of the first 0% to less than 20% of the granulation section of the steel strip granulator is 50 to 80°C, the cooling temperature of the 20% to 40% length is 40 to 50°C, the cooling temperature of the greater than 40% to less than 65% length is 25 to 40°C, and the cooling temperature of the last 65% to 100% length is 15 to 25°C.

[0034] The principle of this invention is as follows: The melt granulation production system and method for triglycidyl isocyanurate of this invention first removes low-volatile organic solvent (methanol) by distillation in a melting kettle. After all the low-volatile organic solvent has been distilled off, the molten material in the melting kettle is transferred to a temporary storage kettle and pumped to a thin-film evaporator. In the thin-film evaporator, a continuous and short residence time is achieved to remove high-boiling-point solvent (epimchlorohydrin), reducing the residual solvent in the particles and avoiding the safety risks caused by carbonization of a large amount of molten material at high temperatures for a long time. The resulting transparent melt material is then conveyed to a crystallizer. Within the crystallizer, the jacket temperature is controlled by adjusting the pushing speed of the third melt pump and the flow rate of cooling water, thus controlling the cooling rate. If the cooling rate is too fast, the material easily solidifies within the crystallizer, making it difficult to control. If the cooling rate is too slow, the seed crystal formation is very slow, and prolonged heat preservation can cause the product to become sticky. Therefore, controlling the optimal cooling rate allows TGIC in the transparent melt to gradually form seed crystals at the optimal point, ensuring uniform seed crystal distribution and enabling rapid granulation. Extensive experimental data shows that when the material's transmittance reaches 15-35%, it remains in a relatively fluid molten state, resulting in the best product forming effect. At this point, the crystallized material is then passed through a distributor, with controlled discharge pressure, forming a uniform liquid that drips evenly onto the steel strip granulator for uniform granulation. Furthermore, this invention is the first to employ zoned gradient cooling of the dripping crystalline material during the granulation process of triglycidyl isocyanurate, which shortens the solidification time, reduces the adhesion of the product to the steel belt granulator, improves production efficiency, and enhances product quality.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] The triglycidyl isocyanurate melt granulation production system and method of the present invention have high production efficiency, good continuity, good safety, and the prepared TGIC particles are free of powder, have stable and uniform quality, and high reliability. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of the melt granulation production system for triglycidyl isocyanurate of the present invention.

[0039] In the diagram, 1. Melting vessel, 2. First melt pump, 3. Temporary storage vessel, 4. Second melt pump, 5. Thin film evaporator, 6. Third melt pump, 7. Crystallizer, 8. Feeder, 9. Fourth melt pump, 10. Digital remote pressure gauge, 11. Steel strip granulator, 12. First condenser, 13. First collection tank, 14. Second condenser, 15. Second collection tank. Detailed Implementation

[0040] To further understand the present invention, preferred embodiments of the present invention are described below. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0041] like Figure 1 As shown, the triglycidyl isocyanurate melt granulation production system of the present invention includes a melting kettle 1, a temporary storage kettle 3, a thin film evaporator 5, a crystallizer 7, a distributor 8, and a steel strip granulator 11; wherein, the outlet of the melting kettle 1 is connected to the inlet of the temporary storage kettle 3 through a first pipe, the outlet of the temporary storage kettle 3 is connected to the inlet of the thin film evaporator 5 through a second pipe, the outlet of the thin film evaporator 5 is connected to the inlet of the third melt pump 6 through a third pipe, the outlet of the third melt pump 6 is connected to the inlet of the crystallizer 7 through a fourth pipe, the outlet of the crystallizer 7 is connected to the inlet of the third melt pump 6 through a fifth pipe, and the outlet of the crystallizer 7 is connected to the inlet of the distributor 8 through a sixth pipe, and the steel strip granulator 11 is located below the outlet of the distributor 8.

[0042] In the above technical solution, preferably, a first melt pump 2 is provided on the first pipeline, a second melt pump 4 is provided on the second pipeline, and a fourth melt pump 9 is provided on the sixth pipeline.

[0043] In the above technical solution, it is preferred that valves are provided on the first, second, third and sixth pipes, and the valves are preferably solenoid valves.

[0044] In the above technical solution, it is preferable to install a digital remote pressure gauge 10 on the sixth pipeline.

[0045] In the above technical solution, the preferred production system further includes a first condenser 12 and a first collection tank 13. One end of the first condenser 12 is connected to the melting vessel 1, and the other end is connected to the first collection tank 13. The first condenser 12 can condense the methanol volatilized in the melting vessel 1 and store it in the first collection tank 13. Usually, the connections are made through pipelines, and preferably, valves are provided on the pipelines.

[0046] In the above technical solution, the preferred production system further includes a second condenser 14 and a second collection tank 15. One end of the second condenser 14 is connected to the thin-film evaporator 5, and the other end is connected to the second collection tank 15. The second condenser 14 can condense the epichlorohydrin volatilized in the thin-film evaporator 5 and store it in the second collection tank 15. The connections are usually made through pipes, and preferably, valves are installed on the pipes, preferably solenoid valves.

[0047] The method for producing triglycidyl isocyanurate by melt granulation of the present invention includes the following steps:

[0048] Step 1: Preparation of TGIC

[0049] The wet powder of methanol-containing triglycidyl isocyanurate was added to melting vessel 1;

[0050] Step 2: Melt distillation

[0051] The methanol-containing triglycidyl isocyanurate wet powder is kept at 65-90℃ for 60-90 min (usually achieved by heating hot water, such as water at 95-98℃, into the jacket of the melting vessel 1 for 40-60 min), and the methanol is removed by distillation. The resulting molten material is then transported to the temporary storage vessel 3.

[0052] Step 3: Vacuum distillation

[0053] First, preheat the thin film evaporator 5 to 105-130℃ and control the pressure at -0.095--0.1 MPa. Then, continuously transport the molten material in the temporary storage vessel 3 to the thin film evaporator 5 and remove epichlorohydrin under reduced pressure to obtain a transparent molten material.

[0054] Step 4: Melting and Crystallization

[0055] The transparent molten material is transported to the crystallizer 7 through the third melt pump 6 and held at 95-105℃ for 20-30 minutes. At the same time, the third melt pump 6 pushes the transparent molten material in the crystallizer 7 to circulate and cool it down to 80-95℃ at a cooling rate of 0.3-0.5℃ / min, controlling the light transmittance at 15-35%, to obtain the crystallized material.

[0056] Step 5: Granulation

[0057] The crystalline material is conveyed to the distributor 8, and the pressure of the crystalline material is controlled at 0.15-0.45 MPa. The crystalline material is then evenly dripped onto the steel belt granulator 11, cooled and shaped to obtain triglycidyl isocyanurate granules.

[0058] In the above technical solution, in step one, the methanol-containing triglycidyl isocyanurate wet powder is obtained as follows: cyanuric acid, epichlorohydrin, and the catalyst benzyltriethylammonium chloride are added to a reaction vessel at a mass ratio of 1:10-15:0.02-0.06, and heated to 100-110℃ under normal pressure for a synthesis reaction. Then, caustic soda is added at a mass ratio of cyanuric acid to caustic soda flakes of 1:1-1.3, and a cyclization reaction is carried out at 15-25℃. The obtained cyclization reaction product is filtered and separated into layers. The lower organic phase is distilled to recover epichlorohydrin, and the distilled material is crystallized with methanol, centrifuged, and the methanol-containing triglycidyl isocyanurate wet powder is added to melting vessel 1.

[0059] In the above technical solution, in step two, it is preferable to maintain the temperature at 70-80℃ for 60-90 minutes. The methanol removed by distillation is preferably condensed in the first condenser 12 and collected in the first collection tank 13. Preferably, step two is carried out under stirring at a stirring speed of 40-60 rpm. In step three, the preheating temperature is preferably 110-120℃. In step three, the epichlorohydrin removed under reduced pressure is preferably condensed in the second condenser 14 and collected in the second collection tank 15. In steps two and three of this invention, the low-volatility organic solvent (methanol) is first removed by distillation in the melting vessel 1. After all the low-volatility organic solvent has been distilled off, the molten material in the melting vessel 1 is transferred to the temporary storage vessel 3 and then transported to the thin-film evaporator 5 by the second melt pump 4. In the thin-film evaporator 5, the high-boiling-point solvent (epicochlorohydrin) is removed continuously and with a short residence time, reducing solvent residue and avoiding the risk of carbonization of a large amount of molten material at high temperature and long duration.

[0060] In the above technical solution, in step four, the preferred heating temperature is 95–100℃, the preferred cooling temperature is 83–90℃, and the transmittance is controlled at 20–30%. Preferably, the self-circulation speed of the transparent melt material pushed by the third melt pump 6 into the crystallizer 7 is 30–60 L / min. Preferably, the crystallizer 7 is supplied with circulating cooling water, and the flow rate of the cooling water is controlled by a valve, preferably a solenoid valve. In step four, the transparent melt is transported to the crystallizer 7. In the crystallizer 7, the driving force generated by the continuous external circulation of the third melt pump 6, combined with the cooling water controlling the cooling rate, gradually generates TGIC crystals in the transparent melt material and controls them at the optimal point. The crystals are evenly distributed, enabling rapid granulation. Furthermore, when the transmittance of the material reaches 15–35%, the material is still in a molten state with good fluidity. At this time, the crystallized material passes through the distributor 8 to form a uniform liquid, which is then evenly dripped onto the steel strip granulator 11 and uniformly granulated. If too little seed crystal is produced, the light transmittance will be low, the solidification time of the transparent melt will be long, and the transparent melt will be sticky. If too much seed crystal is produced, the transparent melt will have poor fluidity and be prone to wall formation, causing material blockage and safety issues.

[0061] In the above technical solution, in step five, the crystalline material is conveyed to the distributor 8 via the fourth melt pump 9. The discharge rate of the fourth melt pump 9 is 30-45 L / min. After passing through the distributor 8, the crystalline material is evenly dripped onto the steel strip granulator 11. The temperature of the steel strip granulator 11 gradually decreases along the direction of the crystalline material's movement, with a temperature range of 15-50℃. Specifically, taking the dripping point of the crystalline material as the starting point, the cooling temperature of the first 0% to less than 20% of the granulation zone of the steel strip granulator is 50-80℃, the cooling temperature of the 20% to 40% length is 40-50℃, the cooling temperature of the greater than 40% to less than 65% length is 25-40℃, and the cooling temperature of the last 65% to 100% length is 15-25℃. If the temperature of the first 20-40% is too high or too low, it will cause the TGIC product granules to take a long time to form and the product to become sticky. If the temperature in the back zone (65%–100%) is too high, the product will become sticky; if the temperature is too low, energy will be wasted.

[0062] The terminology used in this invention generally has the meanings commonly understood by those skilled in the art, unless otherwise stated. To enable those skilled in the art to better understand the technical solutions of this invention, the invention will be further described in detail below with reference to embodiments.

[0063] In the following embodiments, various processes and methods not described in detail are conventional methods known in the art. Unless otherwise specified, the materials, reagents, apparatus, instruments, equipment, etc., used in the following embodiments are commercially available.

[0064] The present invention will be further illustrated below with reference to the embodiments.

[0065] Example 1

[0066] Step 1: By weight, add 100 parts of cyanuric acid, 1200 parts of epichlorohydrin and 3 parts of benzyltriethylammonium chloride catalyst to the reaction vessel, heat to 100-110℃ under normal pressure to carry out the synthesis reaction, then add 105 parts of caustic soda flakes and carry out the cyclization reaction at 25℃. Filter the cyclization reaction product and separate the layers. Distill the lower organic phase to recover epichlorohydrin, and crystallize the distilled material with methanol. Centrifuge to obtain methanol-containing triglycidyl isocyanurate wet powder, which is added to melting vessel 1.

[0067] Step 2: After keeping the methanol-containing triglycidyl isocyanurate wet powder at 80°C for 60 minutes, the methanol is distilled off and recovered to the first collection tank 13. The resulting molten material is then transported to the temporary storage tank 3.

[0068] Step 3: First, preheat the thin film evaporator 5 to 110°C and control the pressure at -0.095 MPa. Then, continuously transport the molten material in the temporary storage vessel 3 to the thin film evaporator 5, remove epichlorohydrin under reduced pressure and recover it to the second collection tank 15 to obtain transparent molten material.

[0069] Step 4: The transparent melt material is transported to the crystallizer 7 through the third melt pump 6 and kept at 98℃ for 20 minutes. At the same time, the third melt pump 6 pushes the transparent melt material in the crystallizer 7 to circulate at a self-circulation speed of 30L / min. The temperature is reduced to 85℃ at a cooling rate of 0.4℃ / min, and the light transmittance is controlled at 25% to obtain the crystal material.

[0070] Step 5: The crystalline material is conveyed to the distributor 8, and the pressure of the crystalline material is controlled at 0.45 MPa. The fourth melt pump 9 rotates at a discharge rate of 30 L / min, and the crystalline material is evenly dripped onto the steel strip granulator 11 for cooling and shaping. The cooling temperature of the first 0% to less than 20% of the length in the granulation zone is 75℃, the cooling temperature of the 20% to 40% length is 50℃, the cooling temperature of the greater than 40% to less than 65% length is 40℃, and the cooling temperature of the last 65% to 100% length is 25℃, to obtain triglycidyl isocyanurate granules (semi-circular).

[0071] Example 2

[0072] Step one is the same as in Example 1;

[0073] Step 2: After keeping the methanol-containing triglycidyl isocyanurate wet powder at 70°C for 90 minutes, the methanol is distilled off and recovered to the first collection tank 13. The resulting molten material is then transported to the temporary storage tank 3.

[0074] Step 3: First, preheat the thin film evaporator 5 to 115°C and control the pressure at -0.1 MPa. Then, continuously transport the molten material in the temporary storage vessel 3 to the thin film evaporator 5, remove epichlorohydrin under reduced pressure and recover it to the second collection tank 15 to obtain transparent molten material.

[0075] Step 4: The transparent melt material is transported to the crystallizer 7 through the third melt pump 6 and kept at 95℃ for 30 minutes. At the same time, the third melt pump 6 pushes the transparent melt material in the crystallizer 7 to circulate at a self-circulation speed of 40L / min. The temperature is reduced to 83℃ at a cooling rate of 0.5℃ / min, and the light transmittance is controlled at 20% to obtain the crystal material.

[0076] Step 5: The crystalline material is conveyed to the distributor 8, and the pressure of the crystalline material is controlled at 0.3 MPa. The fourth melt pump 9 rotates at a discharge rate of 40 L / min, and the crystalline material is evenly dripped onto the steel strip granulator 11 for cooling and shaping. The cooling temperature of the first 0% to less than 20% of the granulation section is 65℃, the cooling temperature of the 20% to 40% of the length is 45℃, the cooling temperature of the greater than 40% to less than 65% of the length is 35℃, and the cooling temperature of the last 65% to 100% of the length is 20℃, to obtain triglycidyl isocyanurate granules (semi-circular).

[0077] Example 3

[0078] Step one is the same as in Example 1;

[0079] Step 2: After keeping the methanol-containing triglycidyl isocyanurate wet powder at 75°C for 80 minutes, the methanol is distilled off and recovered to the first collection tank 13. The resulting molten material is then transported to the temporary storage tank 3.

[0080] Step 3: First, preheat the thin film evaporator 5 to 120°C and control the pressure at -0.1 MPa. Then, continuously transport the molten material in the temporary storage vessel 3 to the thin film evaporator 5, remove epichlorohydrin under reduced pressure and recover it to the second collection tank 15 to obtain transparent molten material.

[0081] Step 4: The transparent melt material is transported to the crystallizer 7 through the third melt pump 6 and kept at 100℃ for 30 minutes. At the same time, the third melt pump 6 pushes the transparent melt material in the crystallizer 7 to circulate at a speed of 50L / min. The temperature is reduced to 90℃ at a cooling rate of 0.3℃ / min, and the light transmittance is controlled at 30% to obtain the crystal material.

[0082] Step 5: The crystalline material is conveyed to the distributor 8, and the pressure of the crystalline material is controlled at 0.3 MPa. The fourth melt pump 9 rotates at a displacement of 45 L / min, and the crystalline material is evenly dripped onto the steel strip granulator 11 for cooling and shaping. The cooling temperature of the first 0% to less than 20% of the granulation section is 60℃, the cooling temperature of the 20% to 40% of the length is 40℃, the cooling temperature of the greater than 40% to less than 65% of the length is 30℃, and the cooling temperature of the last 65% to 100% of the length is 15℃, to obtain triglycidyl isocyanurate granules (semi-circular).

[0083] Comparative Example 1

[0084] Similar to Example 1, except that the light transmittance is controlled at 50%.

[0085] Comparative Example 2

[0086] Similar to Example 1, only the temperature of each zone of the cooling and shaping steel strip was kept constant at 20°C.

[0087] Comparative Example 3

[0088] Similar to Example 1, except that the cooling temperature of the shaped steel strip is as follows: the cooling temperature for the first 0% to less than 20% of the granulation section is 75°C, the cooling temperature for the 20% to 40% of the length is 75°C, the cooling temperature for the greater than 40% to less than 65% of the length is 30°C, and the cooling temperature for the last 65% to 100% of the length is 20°C.

[0089] Comparative Example 4

[0090] Similar to Example 1, except that the cooling temperature of the shaped steel strip is as follows: the cooling temperature for the first 0% to less than 20% of the granulation section is 75°C, the cooling temperature for the 20% to 40% of the length is 45°C, the cooling temperature for the greater than 40% to less than 65% of the length is 40°C, and the cooling temperature for the last 65% to 100% of the length is 40°C.

[0091] Comparative Example 5

[0092] Similar to Example 1, except that the crystallizer was cooled to 85°C at a cooling rate of 0.1°C / min.

[0093] Comparative Example 6

[0094] Steps one through three are the same as in Example 1;

[0095] Step 4: Mix the transparent melt material with 2wt% TGIC dry powder evenly, convey it to the distributor 8 to form a uniform liquid, and drip it evenly onto the steel belt granulator 11. Cool and form at a cooling temperature of 50℃ to obtain triglycidyl isocyanurate granules.

[0096] Comparative Example 7

[0097] Step one is the same as in Example 1;

[0098] Step 2: The wet powder of triglycidyl isocyanurate containing methanol is stirred and kept at 80°C for 60 minutes. Then, it is heated to 90°C and kept at that temperature for 120 minutes. The organic solvent is removed by atmospheric distillation and collected in a collection tank. The solvent is then further removed under vacuum at a pressure controlled at -0.07 MPa. Finally, the molten material is evenly placed on a belt cooling conveyor for cooling and pulverization to obtain triglycidyl isocyanurate granules. (Refer to the specific embodiment of patent CN101773806A)

[0099] Comparative Example 8

[0100] Refer to Example 2 of patent CN108299403A.

[0101] Comparative Example 9

[0102] Comparative Example 2 is based on patent CN114130303A.

[0103] The TGIC particles obtained in Examples 1-3 and Comparative Examples 1-9 were measured, and the process parameters in the preparation methods of Examples 1-3 and Comparative Examples 1-9 were monitored. The results are shown in Table 1.

[0104] Table 1. Performance testing and method monitoring results of TGIC particles obtained in Examples 1-3 and Comparative Examples 1-9

[0105]

[0106]

[0107] As can be seen from Table 1, the TGIC melt granulation production methods of Examples 1-3 produce TGIC particles with low epichlorohydrin content and significantly better storage stability than the products produced by the methods of Comparative Examples 1-9. They also have the advantages of high production efficiency and a good working environment.

[0108] Obviously, the above embodiments are merely examples for clear illustration and are not intended to limit the scope of the embodiments. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all embodiments here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A method for producing triglycidyl isocyanurate by melt granulation, characterized in that, Includes the following steps: Step 1: Add the wet powder of methanol-containing triglycidyl isocyanurate to the melting vessel (1); Step 2: After keeping the methanol-containing triglycidyl isocyanurate wet powder at 65-90℃ for 60-90 min, remove the methanol by distillation, and transport the resulting molten material to a temporary storage vessel (3). Step 3: First, preheat the thin film evaporator (5) to 105-130℃ and control the pressure at -0.095--0.1Mpa. Then, continuously transport the molten material in the temporary storage vessel (3) to the thin film evaporator (5) and remove epichlorohydrin under reduced pressure to obtain a transparent melt material. Step 4: The transparent melt material is transported to the crystallizer (7) through the third melt pump (6) and kept at 95-105℃ for 20-30 minutes. At the same time, the third melt pump (6) pushes the transparent melt material in the crystallizer (7) to circulate and cool it down to 80-95℃ at a cooling rate of 0.3-0.5℃ / min. The light transmittance is controlled at 15-35% to obtain the crystal material. Step 5: The crystalline material is conveyed to the distributor (8), the pressure of the crystalline material is controlled at 0.15-0.45MPa, and the crystalline material is evenly dripped onto the steel belt granulator (11), cooled and shaped to obtain triglycidyl isocyanurate granules. The temperature of the steel strip granulator (11) gradually decreases along the direction of movement of the crystalline material, and the temperature range is 15 to 80°C.

2. The method for producing triglycidyl isocyanurate by melt granulation according to claim 1, characterized in that, In step one, the methanol-containing triglycidyl isocyanurate wet powder is obtained as follows: cyanuric acid, epichlorohydrin and the catalyst benzyltriethylammonium chloride are added to the reaction vessel at a mass ratio of 1:10-15:0.02-0.06, and heated to 100-110°C under normal pressure for synthesis reaction. Then, caustic soda is added at a mass ratio of cyanuric acid to caustic soda flakes of 1:1-1.3, and cyclization reaction is carried out at 15-25°C. The obtained cyclization reaction product is filtered and separated into layers. The lower organic phase is distilled to recover epichlorohydrin, and the distilled material is crystallized with methanol, centrifuged, and the methanol-containing triglycidyl isocyanurate wet powder is added to the melting vessel (1).

3. The method for producing triglycidyl isocyanurate by melt granulation according to claim 1, characterized in that, In step two, methanol is removed by distillation and then condensed in the first condenser (12) and collected in the first collection tank (13). In step three, the epichlorohydrin removed under reduced pressure is condensed in the second condenser (14) and collected in the second collection tank (15).

4. The method for producing triglycidyl isocyanurate by melt granulation according to claim 1, characterized in that, In step four, the third melt pump (6) pushes the transparent melt material in the crystallizer (7) at a self-circulation speed of 30-60 L / min; The crystallizer (7) is supplied with circulating cooling water, and the flow rate of the cooling water is controlled by a valve; Control the light transmittance to 20-30%.

5. The method for producing triglycidyl isocyanurate by melt granulation according to claim 1, characterized in that, In step five, the crystalline material is transported to the distributor (8) by the fourth melt pump (9). The discharge rate of the fourth melt pump (9) is 30-45 L / min, and the crystalline material is evenly dripped onto the steel strip granulator (11).

6. The method for producing triglycidyl isocyanurate by melt granulation according to claim 1, characterized in that, In step five, taking the dripping point of the crystalline material as the starting point, the cooling temperature of the first 0% to less than 20% of the granulation section of the steel strip granulator (11) is 50 to 80°C, the cooling temperature of the 20% to 40% length is 40 to 50°C, the cooling temperature of the greater than 40% to less than 65% length is 25 to 40°C, and the cooling temperature of the last 65% to 100% length is 15 to 25°C.

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