A double-shaft agitator and a vinyl silicone oil production system

Abstract

This invention relates to a biaxial stirrer and a vinyl silicone oil production system. The vinyl silicone oil production system includes several storage tanks, a premixing vessel, a preheater, a catalyst high-pressure homogenizer, a biaxial stirrer, a pressure regulating valve, a terminator high-pressure homogenizer, a flash evaporator, and a first condenser, all connected sequentially by pipelines. The biaxial stirrer designed in this invention is applied to the synthesis of polysiloxanes, exhibiting excellent mixing and interface renewal capabilities for polysiloxanes. It solves the problem of poor mixing due to flow rate limitations in current industrial static pipeline reactors, resulting in a more uniform molecular weight distribution and more stable quality of the produced product.

Description

Technical Field

[0001] This invention relates to the field of vinyl silicone oil production, and in particular to a twin-shaft agitator and a vinyl silicone oil production system. Background Technology

[0002] Vinyl silicone oils, including vinyl-terminated methyl vinyl silicone oils, side-chain vinyl silicone oils, and methyl-terminated side-chain vinyl silicone oils, are mainly used in addition-type liquid silicone rubbers. In China, the production method for vinyl silicone oils employs an intermittent alkaline catalytic process. A measured amount of dehydrated cyclic polymer, catalyst, and end-capping agent are reacted in a reactor for a period of time. A terminator is then added to terminate the polymerization reaction, and low-boiling-point substances are removed by flash evaporation to obtain the product.

[0003] US Patent 4250290 discloses a continuous method for producing polysiloxanes using potassium silanolate as a catalyst, water as a chain terminator, and a static mixer as a reactor. Methylcyclosiloxane is dehydrated and heated before entering the static mixer, where potassium silanolate catalyst and water as a chain terminator are added sequentially. After the required residence time is reached, silicone-based phosphate is added for neutralization. After mixing, the mixture is heated and subjected to flash evaporation under reduced pressure to obtain the polysiloxane.

[0004] US Patent 4551515 discloses a method for the continuous production of high-viscosity polysiloxanes, which is as follows: after mixing and drying the cyclic compound and the end-capping agent (vinyl or methyl end-capping agent), the mixture is preheated to the polymerization temperature in a preheater. Then, potassium silanolate catalyst is added, and the mixture is mixed / prepolymerized in a static mixer. The mixture is then prepolymerized in a cylindrical scraper reactor, and polymerized in a screw extruder. The polymerization reaction is terminated by adding organosilicon phosphate at the appropriate time. After removing low-boiling substances under vacuum, the polysiloxane product is obtained.

[0005] US Patent 6184330 describes a continuous method for producing polysiloxanes. The entire production process consists of three continuous steps: First, in a static mixer, a hydroxyl-terminated polysiloxane condensation reaction, or a ring-opening reaction of cyclosiloxanes, or a mixture of hydroxyl-terminated polysiloxanes and cyclosiloxanes, is carried out under the action of phosphazenes. Second, a neutralization reaction is carried out in a screw extruder, or a static mixer or extruder. Third, low-boiling-point substances generated in the neutralization reaction are removed in a thin-film evaporator or extruder.

[0006] Chinese patent ZL201210478460.6 discloses a method for preparing vinyl silicone oil by using a static mixer as a reactor, methyl cyclic compounds, methyl vinyl cyclic compounds, methyl phenyl cyclic compounds, and end-capping agents as raw materials, polymerizing them under the action of a temporary catalyst, breaking down enzymes, and continuously removing impurities.

[0007] In summary, both domestic and international manufacturers have developed continuous production processes for polysiloxanes using static mixers as reactors. However, the mixing effect of static mixers is limited by the flow rate. Considering the limited residence time, the low flow rate in the pipeline reactor results in poor mixing, leading to a series of problems such as a wide molecular weight distribution of polymers and unstable product quality. Summary of the Invention

[0008] The purpose of this invention is to solve the problem of wide molecular weight distribution and unstable product quality of vinyl silicone oil.

[0009] A dual-shaft mixer includes two parallel stirring shafts, a first stirring shaft and a second stirring shaft, arranged within a first cylindrical body. Each stirring shaft and the first stirring shaft are equipped with a plurality of stirring components. Each stirring component includes a stirring disc and a stirring rod. The stirring disc is fixed to the first and second stirring shafts. Each stirring rod includes a stirring beam and a first vertical rod and a second vertical rod fixed to both ends of the stirring beam. The first and second vertical rods are perpendicular to the stirring beam. The stirring beam is vertically mounted on the outer circumference of the stirring disc and fits against the first cylindrical body, such that the first and second vertical rods are located on opposite sides of the stirring disc. The first and second vertical rods are perpendicular to and point towards either the first or second stirring shaft. A first upper end cover and a first lower end cover are provided at the ends of the first cylindrical body. The first and second stirring shafts extend out of the first cylindrical body through sealing components and are connected to a power mechanism.

[0010] Along the direction of the first stirring shaft and the second stirring shaft, the second vertical rod on the first stirring shaft is located between the stirring plate on the second stirring shaft and the first vertical rod, so that when the first stirring shaft and the second stirring shaft are rotated, the second vertical rod on the first stirring shaft engages with the first vertical rod on the second stirring shaft.

[0011] The first cylinder has a first material inlet on one side and a discharge screw on the other side; the discharge screw has a material outlet.

[0012] A vinyl silicone oil production system employing the above-mentioned biaxial stirrer includes a plurality of storage tanks, a premixing vessel, a preheater, a catalyst high-pressure homogenizer, a biaxial stirrer, a terminator high-pressure homogenizer, a pressure regulating valve, a flash evaporator, and a first condenser connected in sequence by pipelines.

[0013] Furthermore, the storage tank is also connected to the flash evaporator via a pipe equipped with a second condenser.

[0014] Furthermore, the catalyst high-pressure homogenizer includes a third stirring shaft arranged inside the second cylinder, the third stirring shaft having a plurality of first stirring blades, each first stirring blade consisting of a first frame blade and a first auxiliary blade; the second cylinder has a second upper end cover and a second lower end cover; the upper part of the second cylinder has a first feed pipe and the lower part has a first discharge pipe; the first feed pipe has a second material inlet and a catalyst inlet; one end of the third stirring shaft extends out of the second cylinder and is connected to a motor via a drive shaft and a reducer.

[0015] Furthermore, the first propeller is a two-stage propeller or a slant propeller.

[0016] Furthermore, the terminating agent high-pressure homogenizer includes a fourth stirring shaft arranged inside the third cylinder, the fourth stirring shaft having several second stirring blades, each consisting of a second frame blade and a second auxiliary blade; the third cylinder has a third upper end cover and a third lower end cover; the upper part of the third cylinder has a second feed pipe, and the lower part has a second discharge pipe; the feed pipe has a third material inlet and a terminating agent inlet; the middle part of the third cylinder has a carbon dioxide gas inlet; one end of the fourth stirring shaft extends out of the third cylinder and is connected to a motor via a drive shaft and a reducer.

[0017] Furthermore, the second propeller is a two-stage turbine propeller.

[0018] The beneficial effects of this invention are as follows:

[0019] 1. The biaxial stirrer designed in this invention is applied to the synthesis of polysiloxanes. It has good mixing and interface renewal capabilities for polysiloxanes, which solves the problem of poor mixing effect caused by flow rate limitation in current industrial static pipeline reactors. The resulting product has a more uniform molecular weight distribution and more stable quality.

[0020] 2. This invention designs a high-speed homogenizer for trace materials. Through a high-pressure homogenizer for the catalyst and a high-pressure homogenizer for the terminator, the catalyst and terminator can be mixed uniformly in a short time. Simultaneously, in the termination homogenization unit, a method of pre-termination with silicone phosphate ester and post-termination with gaseous carbon dioxide is adopted. This solves the problem of traditional methods that rely on excessive addition of the terminator to ensure complete catalyst termination, resulting in the polysiloxane becoming weakly acidic, thus improving the quality of the polymer. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the process flow of a vinyl silicone oil production system according to the present invention;

[0022] Figure 2 This is a schematic diagram of the catalyst high-pressure homogenizer structure of the present invention;

[0023] Figure 3 This is a schematic diagram of the structure of a dual-shaft stirrer according to the present invention;

[0024] Figure 4 This is a cross-sectional view of a twin-shaft stirrer according to the present invention;

[0025] Figure 5 This is a schematic diagram of the high-pressure homogenizer structure for the terminator of this invention;

[0026] Among them, storage tanks 1-1, 1-2, 1-3, and 1-4; premixing kettle 1-5; preheater 2; catalyst high-pressure homogenizer 3; second cylinder 3-1; second upper end cover 3-2-1; second lower end cover 3-2-2; first feed pipe 3-3; second material feed inlet 3-3-1; catalyst feed inlet 3-3-2; first discharge pipe 3-4; first stirring paddle 3-5; first frame paddle 3-5-1; first auxiliary paddle 3-5-2; third stirring shaft 3-6; dual-shaft agitator 4; first cylinder 4-1; first upper end cover 4-2-1; first lower end cover 4-2-2; first stirring shaft 4-3-1; second stirring shaft 4-3-2; and stirring component 4-4. 4-4-1 mixing disc; 4-4-2 mixing rod; 4-6-1 and 4-6-2 sealing components; 4-7 power mechanism; 4-8 first material inlet; 4-9 discharge screw; 5 high-pressure homogenizer for terminator; 5-1 third cylinder; 5-6 fourth mixing shaft; 5-5 second mixing paddle, 5-5-1 second frame paddle; 5-5-2 second auxiliary paddle; 5-2-2 third upper end cover; 5-2-1 third lower end cover; 5-3 second feed pipe, 5-4 second discharge pipe; 5-3-1 third material inlet; 5-3-2 terminator inlet; 5-7 carbon dioxide gas inlet; 6 flash evaporator; 7 first condenser; 8 second condenser; 9 pressure regulating valve. Detailed Implementation

[0027] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0028] refer to Figure 3-4This invention provides a biaxial stirrer 4, which solves the problem of poor mixing effect caused by flow rate limitation in current industrial static pipeline reactors. A biaxial stirrer 4 includes two parallel stirring shafts 4-3-1 and 4-3-2 arranged within a first cylinder 4-1. The first stirring shaft 4-3-1 is equipped with a plurality of stirring elements 4-4, and the second stirring shaft 4-3-2 is also equipped with a plurality of stirring elements 4-4. Each stirring element 4-4 includes a stirring disc 4-4-1 and a stirring rod 4-4-2. The stirring disc 4-4-1 is fixed to the first stirring shaft 4-3-1 and the second stirring shaft 4-3-2. The stirring rod 4-4-2 includes a stirring beam and a first vertical rod and a second vertical rod fixed to both ends of the stirring beam. The rod is perpendicular to the stirring beam, which is vertically mounted on the outer circumference of the stirring pan 4-4-1 and fits against the first cylinder 4-1, so that the first vertical rod and the second vertical rod are located on both sides of the stirring pan 4-4-1. The first vertical rod and the second vertical rod are perpendicular to and point towards the first stirring shaft 4-3-1 or the second stirring shaft 4-3-2. The first cylinder 4-1 is provided with a first upper end cover 4-2-2 and a first lower end cover 4-2-1. The first stirring shaft 4-3-1 and the second stirring shaft 4-3-2 extend out of the first cylinder 4-1 through sealing components 4-6-1 and 4-6-2 and are connected to the power mechanism 4-7.

[0029] Along the direction of the first stirring shaft 4-3-1 and the second stirring shaft 4-3-2, the second vertical rod on the first stirring shaft 4-3-1 is located between the stirring plate on the second stirring shaft 4-3-2 and the first vertical rod, so that when the first stirring shaft 4-3-1 and the second stirring shaft 4-3-2 are rotated, the second vertical rod on the first stirring shaft 4-3-1 meshes with the first vertical rod on the second stirring shaft 4-3-2;

[0030] The first cylinder 4-1 has a first material inlet 4-8 on one side and a discharge screw 4-9 on the other side; the discharge screw 4-9 has a material outlet.

[0031] refer to Figure 1 This invention provides a vinyl silicone oil production system using the aforementioned biaxial stirrer, comprising, in sequence, storage tanks 1-1, 1-2, 1-3, 1-4, a premixing vessel 1-5, a preheater 2, a catalyst high-pressure homogenizer 3, a biaxial stirrer 4, a terminator high-pressure homogenizer 5, a pressure regulating valve 9, a flash evaporator 6, and a first condenser 7 connected by pipelines; one of the storage tanks 1-4 is connected to the flash evaporator 6 via a condenser pipe equipped with a second condenser 8; alternatively, any one of the storage tanks 1-1, 1-2, and 1-3 can be selected for connection to the flash evaporator 6.

[0032] like Figure 2The catalyst high-pressure homogenizer 3 includes a third stirring shaft 3-6 arranged inside the second cylinder 3-1. The third stirring shaft 3-6 has several first stirring paddles 3-5. Each first stirring paddle 3-5 consists of a first frame paddle 3-5-1 and a first auxiliary paddle 3-5-2. The first auxiliary paddle 3-5-2 is a two-layer propulsion paddle or an inclined paddle. The second cylinder 3-1 has a second upper end cover 3-2-1 and a second lower end cover 3-2-2. The upper part of the second cylinder 3-1 has a first feed pipe 3-3, and the lower part has a first discharge pipe 3-4. The first feed pipe has a second material inlet 3-3-1 and a catalyst inlet 3-3-2. One end of the third stirring shaft 3-6 extends out of the second cylinder 3-1 and is connected to a motor through a drive shaft and a reducer.

[0033] like Figure 5 The terminating agent high-pressure homogenizer 5 includes a fourth stirring shaft 5-6 arranged inside the third cylinder 5-1. The fourth stirring shaft 5-6 has several second stirring paddles 5-5. The second stirring paddles 5-5 consist of a second frame paddle 5-5-1 and a second auxiliary paddle 5-5-2. The second auxiliary paddle 5-5-2 is a two-layer turbine paddle. The third cylinder 5-1 has a third upper end cover 5-2-2 and a third lower end cover 5-2-1. The upper part of the third cylinder 5-1 has a second feed pipe 5-3 and the lower part has a second discharge pipe 5-4. The feed pipe has a third material inlet 5-3-1 and a terminating agent inlet 5-3-2. The middle part of the third cylinder 5-1 has a carbon dioxide gas inlet 5-7. One end of the fourth stirring shaft 5-6 extends out of the third cylinder 5-1 and is connected to the motor through a drive shaft and a reducer.

[0034] The following steps are involved in its use:

[0035] Step 1: Prepare the end-capping agent, vinyl ring, mixed ring, and recycled low molecular weight ring into storage tanks (1-1, 1-2, 1-3, 1-4) respectively. After metering, the mixed ring and end-capping agent are fed into the premixing reactor 1-5. After being mixed evenly, the mixture flows through the preheater 2 and is preheated to the temperature required for the polymerization reaction. Then, it is mixed evenly with the metered catalyst through the catalyst high-pressure homogenizer 3.

[0036] Step 2: After the material exits the catalyst high-pressure homogenizer 3, it enters the twin-shaft stirrer 4 to carry out the polymerization-equilibrium reaction;

[0037] Step 3: After the expected residence time is reached, the material flows out from the twin-shaft agitator 4 and enters the terminator high-pressure homogenizer 5, where it is mixed with the metered terminator and homogenized under high pressure to terminate the polymerization reaction.

[0038] Step 4: After termination, the material enters flash evaporator 6 for depressurized flash evaporation to obtain vinyl silicone oil. The low molecular weight rings recovered from the top of the flash vapor are transported to low molecular weight ring storage tanks 1-4 and returned to the production system.

[0039] The molecular structural formula of vinyl silicone oil is: X(MeRSiO)m(Me2SiO)nMe2SiX, where X is one of methyl and vinyl, R is one or two of methyl and vinyl, 5000≥m + n≥80, m≥0, n≥0.

[0040] The cyclic siloxane raw material is one or several of methylcyclosiloxane (Me2SiO)x and methylvinylcyclosiloxane (MeViSiO)x, where x is 3 - 6; the water content is 10 - 80 ppm, more preferably 10 - 50 ppm, and even more preferably 10 - 20 ppm.

[0041] The end - capping agent is X(Me2SiO)nMe2SiX, where X is one or two of methyl and vinyl, 10 < n < 20; the water content is 10 - 80 ppm, more preferably 10 - 50 ppm, and even more preferably 10 - 20 ppm.

[0042] The catalyst is one of potassium siloxanol, sodium siloxanol, and cesium siloxanol, preferably potassium siloxanol.

[0043] The terminator is one or several of silicophosphates, liquid phosphate terminators, and gas terminators such as carbon dioxide.

[0044] In the pre - heater 2, the cyclic siloxane is pre - heated, and the pre - heating temperature of the cyclic siloxane is 160 - 220 °C, more preferably 170 - 220 °C, and even more preferably 190 - 220 °C.

[0045] The catalyst addition amount is 10 - 50 ppm, more preferably 10 - 30 ppm, and even more preferably 10 - 20 ppm. Its diluent is cyclic siloxane, and the mass concentration is controlled at 10 - 100 g / L, more preferably 10 - 50 g / L, and even more preferably 10 - 20 g / L.

[0046] The average residence time of the catalyst and the mixed cyclic siloxanes in high - pressure homogenization is preferably 5 - 20 min, more preferably 5 - 15 min, and even more preferably 5 - 10 min.

[0047] The polymerization reaction temperature is 160 - 220 °C, more preferably 170 - 220 °C, and even more preferably 190 - 220 °C.

[0048] The average residence time of polymerization is preferably 1 - 5 h, more preferably 1 - 3 h, and even more preferably 1 - 2 h.

[0049] The amount of liquid terminator added is 10-50 ppm, more preferably 10-30 ppm, and even more preferably 10-20 ppm. The diluent for the liquid terminator is a cyclosiloxane, with a mass solubility controlled at 10-100 g / L, more preferably 10-50 g / L, and even more preferably 10-20 g / L;

[0050] The gas terminator is carbon dioxide gas, and the feeding flow rate is 1-10 L / min, more preferably 1-8 L / min, and even more preferably 1-3 L / min.

[0051] The reaction termination temperature is 160-220℃, more preferably 170-220℃, and even more preferably 190-220℃.

[0052] The average residence time for terminating the reaction is 10-60 min, more preferably 10-40 min, and even more preferably 10-20 min.

[0053] The flash evaporation temperature is 160-220℃, more preferably 170-220℃, and even more preferably 190-220℃.

[0054] The absolute pressure for flash de-lowering is preferably 50-800 Pa, more preferably 50-600 Pa, and even more particularly preferably 50-200 Pa.

[0055] Premixing vessels 1-5 are conventional reaction equipment. The specific volume is set according to the material flow rate and residence time requirements. They are kept warm and stirred, with the stirring speed controlled at 50-300 rpm, more preferably 50-200 rpm, and even more preferably 50-100 rpm.

[0056] The catalyst high-pressure homogenizer 3 has a specific volume determined according to the material flow rate and residence time requirements. Internally, it includes a frame impeller + multi-layer propeller impeller, or an inclined impeller, preferably a frame impeller + two-layer propeller impeller, or an inclined impeller, and more preferably a frame impeller + two-layer propeller impeller. The feed section is located slightly above the straight section and consists of a single SV, SX, SH, SL, or SK type static premixer, preferably SV, SX, or SH type, more preferably SV or SX type.

[0057] The catalyst is stirred at a high pressure of 50-300 rpm, more preferably 100-300 rpm, and even more preferably 200-300 rpm.

[0058] The number of stirring components is 2-6, more preferably 2-5, and even more preferably 3-4;

[0059] The mixing speed of the twin-shaft mixer 4 is controlled at 50-200 rpm, more preferably 50-150 rpm, and even more preferably 50-100 rpm.

[0060] The terminator high-pressure homogenizer 5 has a specific volume determined according to the material flow rate and residence time requirements. Internally, it includes a frame impeller with multiple layers of turbine impellers, or a slanted impeller, preferably a frame impeller with two layers of turbine impellers, or a slanted impeller, and more preferably a frame impeller with two layers of propeller impellers. The feed section is located slightly above the straight section and consists of a static premixer of type SV, SX, SH, SL, or SK, preferably type SV, SX, or SH, and more preferably type SV or SX.

[0061] The terminating agent is stirred at a high pressure of 50-300 rpm, more preferably 100-300 rpm, and even more particularly preferably 200-300 rpm.

[0062] The pressure of high-pressure homogenization of the catalyst, polymerization, and terminating agent is the same, and is automatically set and adjusted by a regulating valve. The pressure is 0.5-1.5 MPa, more preferably 0.6-1.5 MPa, and even more preferably 0.7-1.2 MPa.

[0063] The flash evaporator 6 is a conventional device.

[0064] In the embodiment:

[0065] Determination of molecular weight of vinyl silicone oil: Based on the relative molecular weight range of the sample, prepare polystyrene and low molecular weight cyclosiloxane standards, establish a suitable fitting calibration curve, then weigh an appropriate amount of sample, dissolve it in toluene, prepare a sample test solution with a mass concentration of 2 mg / ml, and test it using a gel permeation chromatograph with a differential detector. Finally, use the established calibration curve to calculate the molecular weight and molecular weight distribution of the sample.

[0066] Determination of vinyl content: Weigh 2–10 g (accurate to 0.0001 g) of the sample into a 250 mL iodine flask, add 40 mL of carbon tetrachloride to dissolve the sample, and add 10 mL of iodine bromide solution using a pipette and shake well. React in the dark for 1 hour, then add 50 mL of water and 5 mL of potassium iodide solution. Shake well for 2–3 minutes, then titrate with 0.1 mol / L sodium thiosulfate standard titration solution. Vigorous shaking is necessary during titration. When the upper layer is yellow and the lower layer is pale pink, add 2 mL of starch indicator and titrate with 0.1 mol / L sodium thiosulfate standard titration solution until the blue color just fades.

[0067] Determination of volatile matter in vinyl silicone oil: Using a balance accurate to 0.001g, weigh approximately 2g of polysiloxane in a 75mm diameter glass petri dish, place it in a 150℃ forced-air oven for 3 or 4 hours, weigh it again, and calculate the proportion of mass loss to the initial mass.

[0068] Turbidity determination: The determination shall be carried out in accordance with GB / T 5750.4 (scattering method - formalazine standard).

[0069] The invention will be further explained below with reference to the process flow diagram and structural diagram.

[0070] Example 1: Continuous Preparation of Polyvinyl Silicone Oil

[0071] In this embodiment, a schematic diagram of the process flow of a vinyl silicone oil production system is shown below. Figure 1 As shown; Schematic diagram of catalyst high-pressure homogenizer 3. Figure 2 As shown; a schematic diagram of the twin-shaft stirrer 4 is shown below. Figure 3-4 As shown; Schematic diagram of the high-pressure homogenizer 5 for terminating agent is shown below. Figure 5 As shown.

[0072] Step 1: Prepare the end-capping agent Vi (Me2SiO) 10-20 (water content ~20ppm), vinyl cyclic compound (MeViSiO) 3-4 (water content ~20ppm), methyl mixed cyclic compound (Me2SiO) 4-5 (water content ~30ppm), and recovered low molecular weight cyclic compound separately into storage tanks (1-1, 1-2, 1-3, 1-4). Then, meter and feed the end-capping agent 2.04kg / h, vinyl cyclic compound 1.1kg / h, methyl mixed cyclic compound 86kg / h, and recovered low molecular weight cyclic compound 14kg / h into premixing reactors 1-5, maintain the temperature, control the stirring speed at 80rpm, and maintain an average residence time of 2h. After mixing, the annular material flows through preheater 2 and is preheated to 200±5℃. Then, it enters catalyst high-pressure homogenizer 3 through the second material inlet 3-3-1. The metered potassium silanolate catalyst, with a controlled flow rate of 3.3 mL / min (mass solubility 10 g / L), enters catalyst high-pressure homogenizer 3 through catalyst inlet 3-3-2. The two materials are initially premixed through an SV-type static mixer with a length of 30 cm and a diameter of 50 mm, and further homogenized under high pressure in catalyst high-pressure homogenizer 3 until uniformly mixed. The stirring paddle 3-5 of catalyst high-pressure homogenizer 3 is a combination of frame paddle 3-5-1 and two-layer propeller paddle 3-5-2, with a controlled stirring speed of 200 rpm and a mixing residence time of 5 min.

[0073] Step 2: The mixed cyclic material flows out of the catalyst high-pressure homogenizer 3 from the first discharge pipe 3-4 and enters the twin-shaft stirrer 4 through the feed port 4-8 to carry out the polymerization-equilibrium reaction. The polymerization pressure is controlled at 0.9MPa, the temperature at 193±5℃, the reactor stirring speed at 60rpm, and the average polymerization residence time at 1h.

[0074] Step 3: After reaching the expected residence time, the polymer material flows out of the twin-shaft agitator 4 from outlet 4-9 and enters the terminator high-pressure homogenizer 5 through the third material inlet 5-3-1. The flow rate of the terminator silicone phosphate is controlled at 4.0 mL / min (mass concentration 10 g / L), and it enters the terminator high-pressure homogenizer 5 through the terminator inlet 5-3-2. The two materials are initially pre-mixed through an SX-type static mixer with a length of 30 cm and a diameter of 50 mm, and then further homogenized under high pressure through the terminator high-pressure homogenizer 5. The carbon dioxide terminator is homogenized under high pressure through the carbon dioxide gas inlet 5-7, with the flow rate controlled at 1 L / min, until the mixture is homogeneous and the reaction is uniform. The second agitator 5-5 of the terminator high-pressure homogenizer 5 is a combination of a frame paddle 5-5-1 and two-layer turbine paddles 5-5-2, with the stirring speed controlled at 250 rpm and the residence time at 10 min.

[0075] Step 4: After termination, the material enters flash evaporator 6 for reduced pressure flash evaporation, with the temperature controlled at 190±5℃ and the vacuum at 60Pa, to obtain vinyl silicone oil with a viscosity of 98600cp, molecular weight distribution of 1.74, vinyl content of 1.02%, volatile matter of 0.58%, and turbidity of 0.8NUT. The flash evaporation low molecular weight cyclic vapor is condensed and recovered at the top and transported to low molecular weight cyclic storage tanks 1-4, returning to the production system.

[0076] Example 2: Continuous preparation of vinyl-terminated silicone oil

[0077] In this embodiment, a schematic diagram of the process flow of a vinyl silicone oil production system is shown below. Figure 1 As shown; Schematic diagram of catalyst high-pressure homogenizer 3. Figure 2 As shown; a schematic diagram of the twin-shaft stirrer 4 is shown below. Figure 3-4 As shown; Schematic diagram of the high-pressure homogenizer 5 for terminating agent is shown below. Figure 5 As shown.

[0078] Step 1: Prepare the end-capping agent Vi(Me2SiO)10-20Me2SiVi (water content ~20ppm), methyl mixed cyclic (Me2SiO)4-5 (water content ~30ppm), and molten methylphenyl mixed cyclic (Ph2ViSiO)3 (water content ~30ppm) separately into storage tanks (1-1, 1-2, 1-3, 1-4). Then, meter and feed the end-capping agent (3.2kg / h), methyl mixed cyclic (83kg / h), and recovered low-molecular-weight cyclic (17kg / h) into premixing reactors (1-5), maintain the temperature, control the stirring speed at 100rpm, and maintain an average residence time of 2h. After mixing, the cyclic material is preheated to 203±5℃ in a preheater, and then enters the catalyst high-pressure homogenizer 3 through inlet 3-3-1. The metered potassium silanolate catalyst, with a controlled flow rate of 3.3mL / min (mass solubility 10g / L), enters the catalyst high-pressure homogenizer 3 through inlet 3-3-2. The two materials are initially premixed through an SV-type static mixer with a length of 30cm and a diameter of 50mm, and then further homogenized under high pressure in the catalyst high-pressure homogenizer until uniformly mixed. The catalyst high-pressure homogenizer's agitator 3-5 is a combination of a frame agitator 3-5-1 and a two-layer propeller agitator 3-5-2, with a controlled stirring speed of 250rpm and a mixing residence time of 5min.

[0079] Step 2: The mixed cyclic material flows out of the catalyst high-pressure homogenizer 3 from the discharge port 3-4 and enters the twin-shaft agitator 4 through the feed port 4-8 to carry out the polymerization-equilibrium reaction. The polymerization pressure is controlled at 0.8MPa, the temperature at 200±5℃, the reactor stirring speed at 80rpm, and the average polymerization residence time at 1h.

[0080] Step 3: After reaching the expected residence time, the polymer material flows out of the twin-shaft agitator 4 from outlet 4-9 and enters the terminator high-pressure homogenizer 5 through polymer material inlet 5-3-1. The flow rate of the terminator silicone phosphate is controlled at 4.0 mL / min (mass concentration 10 g / L), and it enters the terminator high-pressure homogenizer 5 through inlet 5-3-2. The two materials are initially pre-mixed through an SX-type static mixer with a length of 30 cm and a diameter of 50 mm, and then further homogenized under high pressure through the terminator homogenizer. The carbon dioxide terminator is introduced through inlet 5-7, with the flow rate controlled at 2 L / min, and is homogenized under high pressure until the mixture is uniform and the reaction is homogeneous. The agitator 5-5 of the terminator homogenizer is a combination of a frame paddle 5-5-1 and two-layer turbine paddles 5-5-2, with the stirring speed controlled at 300 rpm and the residence time at 10 min.

[0081] Step 4: After termination, the material enters flash evaporator 6 for reduced pressure flash evaporation, with the temperature controlled at 195±5℃ and the vacuum at 60Pa, to obtain end-vinyl silicone oil with a viscosity of 21500cp, molecular weight distribution of 1.72, vinyl content of 0.286%, volatile matter of 0.47%, and turbidity of 0.8NUT. The flash evaporation low molecular weight cyclic vapor is condensed and recovered at the top and transported to low molecular weight cyclic storage tanks 1-4, returning to the production system.

[0082] Example 3: Continuous preparation of methyl silicone oil

[0083] In this embodiment, a schematic diagram of the process flow of a vinyl silicone oil production system is shown below. Figure 1 As shown; Schematic diagram of catalyst high-pressure homogenizer 3. Figure 2 As shown; a schematic diagram of the twin-shaft stirrer 4 is shown below. Figure 3-4 As shown; Schematic diagram of the high-pressure homogenizer 5 for terminating agent is shown below. Figure 5 As shown.

[0084] Step 1: Prepare the end-capping agent Me(Me2SiO) 10-20 (water content ~20ppm), methyl mixed cyclic compound (Me2SiO) 4-5 (water content ~30ppm), and the recovered low molecular weight cyclic compound separately into storage tanks (1-1, 1-2, 1-3). Then, meter and feed the end-capping agent 1.38kg / h, methyl mixed cyclic compound 85kg / h, and recovered low molecular weight cyclic compound 15kg / h into premixing reactors 1-5, maintain the temperature, control the stirring speed at 100rpm, and maintain an average residence time of 2h. After mixing, the cyclic material is preheated to 200±5℃ in a preheater, and then enters the catalyst high-pressure homogenizer 3 through inlet 3-3-1. The metered potassium silanolate catalyst, with a controlled flow rate of 3.3mL / min (mass solubility 10g / L), enters the catalyst high-pressure homogenizer 3 through inlet 3-3-2. The two materials are initially premixed through an SV-type static mixer with a length of 30cm and a diameter of 50mm, and then further homogenized under high pressure in the catalyst high-pressure homogenizer until uniformly mixed. The catalyst high-pressure homogenizer's agitator 3-5 is a combination of a frame agitator 3-5-1 and a two-layer propeller agitator 3-5-2, with a controlled stirring speed of 300rpm and a mixing residence time of 5min.

[0085] Step 2: The mixed cyclic material flows out of the catalyst high-pressure homogenizer 3 from the discharge port 3-4 and enters the twin-shaft agitator 4 through the feed port 4-8 to carry out the polymerization-equilibrium reaction. The polymerization pressure is controlled at 1.1MPa, the temperature at 195±5℃, the reactor stirring speed at 50rpm, and the average polymerization residence time at 1h.

[0086] Step 3: After reaching the expected residence time, the polymer material flows out of the twin-shaft agitator 4 from outlet 4-9 and enters the terminator high-pressure homogenizer 5 through polymer material inlet 5-3-1. The flow rate of the terminator silicone phosphate is controlled at 4.0 mL / min (mass concentration 10 g / L), and it enters the terminator high-pressure homogenizer 5 through inlet 5-3-2. The two materials are initially pre-mixed through an SX-type static mixer with a length of 30 cm and a diameter of 50 mm, and then further homogenized under high pressure in the terminator homogenizer. The carbon dioxide terminator is homogenized under high pressure through inlet 5-7 at a controlled flow rate of 3 L / min until the mixture and reaction are uniform. The agitator 5-5 of the terminator homogenizer is a combination of a frame paddle 5-5-1 and a two-layer turbine paddle 5-5-2, with the stirring speed controlled at 200 rpm and the residence time at 10 min.

[0087] Step 4: After termination, the material enters flash evaporator 6 for reduced pressure flash evaporation, with the temperature controlled at 193±5℃ and vacuum, to obtain methyl silicone oil with a viscosity of 337000cp, molecular weight distribution of 1.76, volatile matter of 0.32%, and turbidity of 0.85NUT. The flash evaporation low molecular weight cyclic vapor is condensed and recovered at the top and transported to low molecular weight cyclic storage tanks 1-4, returning to the production system.

[0088] Comparative Example 1

[0089] This comparative example, Figure 1 In the process flow shown, the twin-shaft agitator 4 is replaced with a static pipeline reactor, and the catalyst high-pressure homogenizer 3 and the terminator high-pressure homogenizer 5 are replaced with static mixers.

[0090] Step 1: Prepare the end-capping agent Vi (Me2SiO) 10-20 (water content ~20ppm), vinyl cyclic compound (MeViSiO) 3-4 (water content ~20ppm), methyl mixed cyclic compound (Me2SiO) 4-5 (water content ~30ppm), and recovered low molecular weight cyclic compound separately into storage tanks (1-1, 1-2, 1-3, 1-4). Then, meter and feed the end-capping agent 2.04kg / h, vinyl cyclic compound 1.1kg / h, methyl mixed cyclic compound 86kg / h, and recovered low molecular weight cyclic compound 14kg / h into premixing reactors 1-5, maintain the temperature, control the stirring speed at 80rpm, and maintain an average residence time of 2h. After mixing, the mixed ring material is preheated to 200±5℃ by a preheater, and then enters a static mixer. The metered potassium silanolate catalyst is controlled at a flow rate of 3.3mL / min (mass solubility 10g / L) and enters the static mixer through a nozzle. The two materials are mixed through an SV-type static mixer with a length of 30cm and a diameter of 50mm.

[0091] Step 2: The mixed cyclic material and potassium silanolate catalyst are mixed in a static mixer and then flow out into an SX-type static pipeline reactor with a length of 4.0 meters and a diameter of 150 mm through the feed inlet to carry out the polymerization-equilibrium reaction. The polymerization pressure is controlled at 0.9 MPa, the temperature at 193±5℃, and the average polymerization residence time is 1 hour.

[0092] Step 3: After reaching the expected residence time, the polymer material flows out of the outlet of the static pipeline reactor and enters the terminal static mixer. The flow rate of the terminator, silicon-based phosphate ester, is controlled at 4.0 mL / min (mass concentration 10 g / L), and it enters the terminal static mixer through a nozzle. The two materials are mixed through an SX-type static mixer with a length of 30 cm and a diameter of 50 mm. The carbon dioxide terminator enters another SX-type static mixer with a length of 30 cm and a diameter of 50 mm through the inlet, with the flow rate controlled at 1 L / min. After passing through the two static mixers connected in series, the material flows into the SX-type pipeline reactor with a length of 1.0 m and a diameter of 100 mm to terminate the reaction, with a final residence time of 10 min.

[0093] Step 4: After termination, the material enters flash evaporator 6 for reduced pressure flash evaporation, with the temperature controlled at 190±5℃ and the vacuum at 60Pa, to obtain vinyl silicone oil with a viscosity of 96200cp, molecular weight distribution of 1.94, vinyl content of 1.03%, volatile matter of 0.58%, and turbidity of 0.8NUT. The flash evaporation low molecular weight cyclic vapor is condensed and recovered at the top and transported to low molecular weight cyclic storage tanks 1-4, returning to the production system.

[0094] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A vinyl silicone oil production system, characterized in that, It includes several storage tanks, a premixing kettle, a preheater, a catalyst high-pressure homogenizer, a twin-shaft agitator, a terminator high-pressure homogenizer, a pressure regulating valve, a flash evaporator, and a first condenser, which are connected in sequence by pipelines. The dual-shaft agitator includes two parallel agitation shafts, a first agitation shaft and a second agitation shaft, arranged within a first cylindrical body. Each agitation shaft and a second agitation shaft is equipped with several agitation components. Each agitation component includes a mixing disc and a mixing rod. The mixing disc is fixed to the first and second agitation shafts. The mixing rod includes a mixing beam and a first vertical rod and a second vertical rod fixed to both ends of the mixing beam. The first and second vertical rods are perpendicular to the mixing beam. The mixing beam is vertically mounted on the outer circumference of the mixing disc and fits against the first cylindrical body, such that the first and second vertical rods are located on opposite sides of the mixing disc. The first cylinder body is provided with a first upper end cover and a first lower end cover at its end. The first and second stirring shafts extend out of the first cylinder body through sealing components and are connected to a power mechanism. Along the direction of the first and second stirring shafts, a second vertical rod on the first stirring shaft is located between the stirring disc on the second stirring shaft and the first vertical rod, so that when the first and second stirring shafts are rotated, the second vertical rod on the first stirring shaft engages with the first vertical rod on the second stirring shaft. One side of the first cylinder body has a first material inlet, and the other side has a discharge screw. The discharge screw has a material outlet. The terminating agent high-pressure homogenizer includes a fourth stirring shaft arranged inside a third cylinder, the fourth stirring shaft having several second stirring blades, each consisting of a second frame blade and a second auxiliary blade; the third cylinder has a third upper end cover and a third lower end cover; the upper part of the third cylinder has a second feed pipe, and the lower part has a second discharge pipe; the second feed pipe has a third material inlet and a terminating agent inlet; the middle part of the third cylinder has a carbon dioxide gas inlet; one end of the fourth stirring shaft extends out of the third cylinder and is connected to a motor via a drive shaft and a reducer.

2. The vinyl silicone oil production system according to claim 1, characterized in that, The storage tank is also connected to the flash evaporator via a pipe equipped with a second condenser.

3. The vinyl silicone oil production system according to claim 1, characterized in that, The catalyst high-pressure homogenizer includes a third stirring shaft arranged inside a second cylinder, the third stirring shaft having a plurality of first stirring blades, each first stirring blade consisting of a first frame blade and a first auxiliary blade; the second cylinder has a second upper end cover and a second lower end cover; the upper part of the second cylinder has a first feed pipe and the lower part has a first discharge pipe; the first feed pipe has a second material inlet and a catalyst inlet; One end of the third stirring shaft extends out of the second cylinder and is connected to the motor via a drive shaft and a reducer.

4. A vinyl silicone oil production system according to claim 3, characterized in that, The first propeller is either a two-stage propeller or a slant propeller.

5. A vinyl silicone oil production system according to claim 1, characterized in that, The second propeller is a two-stage turbine propeller.

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