CN110256612B - Preparation method of chlorinated polyvinyl chloride - Google Patents
Preparation method of chlorinated polyvinyl chloride Download PDFInfo
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- CN110256612B CN110256612B CN201910614160.8A CN201910614160A CN110256612B CN 110256612 B CN110256612 B CN 110256612B CN 201910614160 A CN201910614160 A CN 201910614160A CN 110256612 B CN110256612 B CN 110256612B
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2/00—Processes of polymerisation
- C08F2/12—Polymerisation in non-solvents
- C08F2/16—Aqueous medium
- C08F2/18—Suspension polymerisation
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F8/00—Chemical modification by after-treatment
- C08F8/18—Introducing halogen atoms or halogen-containing groups
- C08F8/20—Halogenation
- C08F8/22—Halogenation by reaction with free halogens
Abstract
The invention provides a chlorinated polyA method for preparing vinyl chloride, said method comprising the steps of: preparing a suspension solution and performing chlorination reaction; the chlorination reaction comprises a first-stage chlorination and a second-stage chlorination; the CPVC resin prepared by the method has the advantages of dry powder fluidity of 15-25s, elastic modulus of 2654-2816MPa, high rigidity, tensile strength of 52-58MPa and impact strength of 17-22kJ/m of simple beam2(ii) a The comprehensive performance is excellent; according to the invention, no initiator is added, so that the influence of initiator residues on the color and the thermal stability of the product is reduced; meanwhile, the reaction time is short, and the chlorination reaction time is 125-150 min. The concentration of hydrochloric acid is increased to more than 22% in the chlorination process, the purification process reduces impurities, the impurities can be recycled, the redundant parts can be sold, the method is directly applied to metal metallurgy, organic synthesis, calcium chloride production and the like, the comprehensive utilization of the hydrochloric acid is realized, and the method is environment-friendly and energy-saving.
Description
Technical Field
The invention provides a preparation method of chlorinated polyvinyl chloride, belonging to the technical field of chlorinated polyvinyl chloride preparation.
Background
The CPVC resin is obtained after PVC is subjected to chlorination modification, the physical and mechanical properties, corrosion resistance, deformation resistance, flame retardance, smoke suppression and the like of the CPVC resin are greatly improved, particularly the heat resistance is improved, the application of the CPVC resin is expanded to the high-performance field, and the CPVC resin is applied to heat-resistant water pipes, pressure-resistant and corrosion-resistant industrial pipelines and fire-fighting pipelines with high flame retardance requirements, and has obvious advantages.
At present, the chlorinated polyvinyl chloride is mainly produced by an aqueous phase suspension method, and the method generates low-concentration dilute hydrochloric acid, has low utilization value and large treatment difficulty, and is not an environment-friendly process. CN105461833A discloses an acid phase method for producing chlorinated polyvinyl chloride resin, which comprises heating the prepared suspension to 70-80 deg.C, adding initiator, and performing chlorination reaction at 110 deg.C. The reaction temperature of the process is high and the decomposition tendency of the product is aggravated. CN104558305B discloses a process for synthesizing chlorinated polyvinyl chloride by acid phase suspension method, which comprises using acid phase as reaction medium, adding polyvinyl chloride, dispersant A, dispersant B and initiator, slowly heating to emulsify to 80 deg.C, and starting chlorination reaction from 85 deg.C. In order to ensure the smooth reaction, the initiator is added, and the ratio of the polyvinyl chloride to the initiator is 10:0.015, so that the photo-thermal stability of the PVC is reduced, and the quality of a final product is adversely affected.
The CPVC is synthesized by the existing acid phase method, and the defects are as follows:
(1) in order to ensure that the initiator is added during the reaction, the residue of the initiator can reduce the photo-thermal stability of PVC and can also reduce the thermal stability and the service life of a final product, and the reaction speed is slow and the reaction time is long without adding the initiator;
(2) under an acid phase system, products are easy to agglomerate and agglomerate in the reaction process; the dry powder flowability of the prepared CPVC resin is poor;
(3) the rigidity and the deformation resistance of the prepared product are reduced, and the product is not beneficial to installation and use.
Disclosure of Invention
In order to solve the technical problem, the invention provides a preparation method of chlorinated polyvinyl chloride, which realizes the following purposes:
(1) in the chlorination process, no initiator is added, so that the influence of the initiator residue on the product quality is reduced; meanwhile, the reaction time is shortened;
(2) the product agglomeration and caking in the reaction process are prevented, and the free flowability of the CPVC resin is improved;
(3) the elastic modulus of the product is improved, and the rigidity and the deformation resistance are enhanced.
In order to solve the technical problems, the invention adopts the following technical scheme:
a method for preparing chlorinated polyvinyl chloride, comprising the steps of: preparing a suspension solution and performing chlorination reaction; the chlorination reaction comprises a first-stage chlorination and a second-stage chlorination.
The preparation method comprises the steps of preparing a suspension solution, adding a hydrochloric acid solution, PVC resin, a dispersing agent and an anti-sticking agent into a chlorination kettle, and uniformly stirring to prepare the suspension solution. The amount of the dispersant is 0.02-1.0% of the PVC resin, preferably 0.1-0.8%, and the amount of the anti-sticking agent is 0.08-1.6% of the PVC resin, preferably 0.4-1.5%; the solid-liquid ratio (the weight ratio of the PVC resin to the hydrochloric acid solution) is 1:3-1: 9.
The concentration of the hydrochloric acid solution is 16-21% (weight ratio).
The polymerization degree range of the PVC resin is 500-2500, the optimized selection range is 650-1500, and the more preferable selection range is 650-1300; the average particle size range is 160-230 μm, and the optimal selection is 180-210 μm; the apparent density is 0.55g/ml-0.65 g/ml.
The high and low degree of polymerization represents the molecular weight of the PVC resin and is a main factor influencing the performance of products. The granularity and apparent density of PVC affect the loading factor and load of the chlorination reaction and have an effect on the granularity of the CPVC resin. Fine particles, high dispersion difficulty, easy agglomeration and caking of the product, poor flowability of the CPVC dry powder, coarse particles, uneven chlorination and reduced product quality.
The dispersing agent is one or two of sodium dodecyl benzene sulfonate, sodium polymethacrylate, a copolymer of ethylene oxide and propylene oxide, polyvinylpyrrolidone and polyether surfactant;
the anti-sticking agent is one of talcum powder, silicon dioxide and silicone oil;
and (3) performing chlorination reaction, vacuumizing to-0.06 to-0.08 MPa, and removing oxygen in the kettle. Opening a steam valve to heat, simultaneously opening a chlorine valve to introduce chlorine, setting the initial temperature of the reaction to be 40-50 ℃, the ending temperature of the reaction to be 80-100 ℃, preferably 81-95 ℃, the set pressure to be 0.3-0.4MPa, and the weight ratio of the chlorine introduction amount to the PVC resin to be 0.4-0.9.
And in the first-stage chlorination, chlorine is uniformly introduced from the initial temperature, the chlorine introduction and the temperature rise are carried out simultaneously, when the chlorine introduction time is 1.5h, the pressure in the kettle reaches the set pressure, the chlorine introduction amount reaches 50% -80%, preferably 55-75% of the total chlorine introduction amount, and the reaction temperature is 80% -98%, preferably 81.5-95.7% of the termination temperature.
And (3) in the second stage, chlorination, heating at a constant speed, continuously introducing chlorine gas, and maintaining the reaction pressure constant at a set pressure.
In the first stage of chlorination, the heating rate is 1.5-2 ℃/5 min;
and in the second stage of chlorination, the heating rate is 0.5-1.2 ℃/5min, and the reaction time is 35-60 min.
The preparation method also comprises post-treatment, wherein the chlorinated polyvinyl chloride is deacidified, dehydrated and dried to obtain a chlorinated polyvinyl chloride finished product. The obtained hydrochloric acid solution enters a hydrochloric acid storage tank after being purified.
The product obtained by the reaction is uniformly chlorinated, the dry powder fluidity of the CPVC resin is less than 26s, the elastic modulus is more than or equal to 2500MPa, the rigidity is good, and the comprehensive performance is excellent.
The solid suspended substance in the purified hydrochloric acid solution is less than or equal to 10 mg/L.
Compared with the prior art, the invention has the beneficial effects that:
(1) the CPVC resin prepared by the method has the advantages of dry powder fluidity of 15-25s, elastic modulus of 2654-2816MPa, high rigidity, tensile strength of 52-58MPa and impact strength of 17-22kJ/m of simple beam2(ii) a The comprehensive performance is excellent.
(2) According to the invention, no initiator is added, so that the influence of initiator residues on the color and the thermal stability of the product is reduced; meanwhile, the reaction time is short, and the chlorination reaction time is 125-150 min.
(3) The concentration of hydrochloric acid is increased to more than 22% in the chlorination process, the purification process reduces impurities, the impurities can be recycled, the redundant parts can be sold, the method is directly applied to metal metallurgy, organic synthesis, calcium chloride production and the like, the comprehensive utilization of the hydrochloric acid is realized, and the method is environment-friendly and energy-saving.
Detailed Description
Example 1:
(1) preparation of the suspension solution
In the chlorination kettle, 4m of the solution is added3Diluted hydrochloric acid, concentration 19% (weight ratio), PVC resin 700kg, used PVC resin polymerization degree of 1000, particle average diameter of 200 μm, apparent density of 0.6 ml/g. 4Kg of sodium polymethacrylate and 6Kg of talcum powder are uniformly stirred to prepare a suspension solution.
(2) Chlorination reaction
Setting the initial reaction temperature to be 48 ℃, the termination reaction temperature to be 85 ℃ and the reaction pressure to be less than or equal to 0.35 MPa.
A. First stage chlorination
Vacuumizing to-0.065 MPa, reacting at 48 deg.C, introducing chlorine gas, and heating. After chlorine was introduced for 1.5 hours, the amount of chlorine introduced was 305kg, the reaction temperature was 76.5 ℃ and the pressure reached 0.35 MPa.
The heating rate is 1.6 ℃/5 min;
B. second stage chlorination
Adjusting the heating rate to 1 ℃/5min, continuously introducing chlorine gas, and keeping the reaction pressure at 0.35 MPa;
the temperature is raised to 85 ℃, and the reaction is finished, wherein the reaction time is 43 min.
The total amount of chlorine gas introduced in the two stages was 470Kg, and the chlorine content of the resulting chlorinated polyvinyl chloride resin was 67.5% (by weight).
(3) Post-treatment
Deacidifying, dehydrating and drying the chlorinated polyvinyl chloride to obtain a chlorinated polyvinyl chloride resin finished product, wherein the fluidity of dry powder is 19 s. The obtained product has the test performance, and the tensile elastic modulus is 2750 MPa; the tensile strength is 53MPa, and the impact strength of the simply supported beam is 20kJ/m2；
The obtained hydrochloric acid solution enters a hydrochloric acid storage tank after being purified. The solid suspended substance in the purified hydrochloric acid solution is less than or equal to 10 mg/L.
Example 2
(1) Preparation of the suspension solution
In the chlorination kettle, 4m of the solution is added3Diluted hydrochloric acid, concentration 17.3% (weight ratio), PVC resin 960kg, polymerization degree of used PVC resin 1300, average particle diameter of particles 180 μm, apparent density 0.63 g/ml. 400g of polyvinylpyrrolidone, 600g of copolymer of ethylene oxide and propylene oxide and 3.8Kg of silicone oil are stirred uniformly to prepare a suspension solution.
(2) Chlorination reaction
Setting the initial reaction temperature at 50 deg.c, the final reaction temperature at 95 deg.c and the pressure not more than 0.4 MPa.
A. First stage chlorination
Vacuumizing to-0.080 MPa,The reaction temperature is 50 ℃, chlorine is introduced, and the chlorine introduction and the temperature rise are carried out simultaneously. After chlorine is introduced for 1.5h, the chlorine introducing amount is 264kg, the reaction temperature is 81.5 ℃, and the pressure reaches 0.4 MPa.
The heating rate was 1.75 deg.C/5 min.
B. Second stage chlorination
Adjusting the heating rate to 1.2 ℃/5min, continuously introducing chlorine gas, and keeping the reaction pressure at 0.4 MPa;
the temperature is raised to 95 ℃, and the reaction is finished for 56 min.
The total amount of chlorine gas introduced in the two stages is 480Kg, and the chlorine content of the obtained chlorinated polyvinyl chloride resin is 65.1% (weight ratio).
(3) Post-treatment
Deacidifying, dehydrating and drying the chlorinated polyvinyl chloride to obtain a chlorinated polyvinyl chloride resin finished product, wherein the fluidity of dry powder is 15 s. The obtained product has the test performance that the tensile elastic modulus is 2816MPa, the tensile strength is 58MPa, and the impact strength of a simply supported beam is 22kJ/m2；
The obtained hydrochloric acid solution enters a hydrochloric acid storage tank after being purified. The solid suspended substance in the purified hydrochloric acid solution is less than or equal to 10 mg/L.
Example 3
(1) Preparation of the suspension solution
In the chlorination kettle, 4m of the solution is added3Diluted hydrochloric acid, concentration 21% (weight ratio), PVC resin 510kg, polymerization degree of used PVC resin 650, average particle diameter of particles 220 μm, apparent density 0.56 g/ml. 4Kg of a copolymer of ethylene oxide and propylene oxide and 7.5Kg of silica were uniformly stirred to prepare a suspension.
(2) Chlorination reaction
Setting the initial reaction temperature at 42 deg.c, the final reaction temperature at 81 deg.c and the pressure not more than 0.3 MPa.
A. First stage chlorination
Vacuumizing to-0.070 MPa, controlling the reaction temperature to be 42 ℃, introducing chlorine and heating simultaneously, introducing chlorine for 1.5h, controlling the chlorine introducing amount to be 300kg, controlling the reaction temperature to be 77.5 ℃, and controlling the pressure to be 0.3 MPa.
The heating rate was 1.97 deg.C/5 min.
B. Second stage chlorination
Adjusting the heating rate to 0.5 ℃/5min, continuously introducing chlorine gas, and keeping the reaction pressure at 0.3 MPa;
the temperature is raised to 81 ℃, and the reaction is finished for 35 min.
The total amount of chlorine gas introduced in the two stages is 400Kg, and the chlorine content of the obtained chlorinated polyvinyl chloride resin is 69.1% (weight ratio).
(3) Post-treatment
Deacidifying, dehydrating and drying the chlorinated polyvinyl chloride to obtain a chlorinated polyvinyl chloride resin finished product, wherein the fluidity of dry powder is 25 s. The obtained product has the test performance that the tensile elastic modulus is 2654MPa, the tensile strength is 52MPa, and the impact strength of the simply supported beam is 17.6kJ/m2，
The obtained hydrochloric acid solution enters a hydrochloric acid storage tank after being purified. The solid suspended substance in the purified hydrochloric acid solution is less than or equal to 10 mg/L.
Comparative example 1
(1) Preparation of the suspension solution
In the chlorination kettle, 4.1m is added3Stirring dilute hydrochloric acid with concentration of 20% (weight ratio), PVC resin 850Kg, sodium methacrylate 5Kg, benzoyl peroxide 1.5Kg and pulvis Talci 7Kg to prepare suspension, raising temperature to 60 deg.C, soaking and emulsifying for 30 min;
the polymerization degree of the PVC resin is 700, and the average particle size range is 120 mu m; the apparent density was 0.52 g/ml.
(2) Chlorination reaction
Pressing the suspension solution into a chlorination kettle, sealing, introducing nitrogen with the pressure of 0.1MPa for 30min, vacuumizing to-0.06 MPa, and discharging oxygen in the chlorination kettle.
During the chlorination, the initial reaction temperature T0 was 60 ℃, the temperature T1 was 90 ℃, the temperature T2 was 100 ℃ and the final reaction temperature T3 was 110 ℃. Setting the total chlorine passing amount to be 570kg, the chlorine passing amount in a T0-T1 interval to be 208kg, the chlorine passing time to be 1.3h, the chlorine passing amount in a T1-T2 interval to be 253kg, the chlorine passing time to be 1.1h, the chlorine passing amount in a T2-T3 interval to be 109kg and the chlorine passing time to be 1.3 h. And (5) after chlorine introduction, keeping the temperature for 10 min. The pressure in the kettle is less than or equal to 0.4MPa in the reaction process.
(3) Post-treatment
Deacidifying, dehydrating and drying chlorinated polyvinyl chloride to obtain a chlorinated polyvinyl chloride resin finished product, wherein the chlorine content of the obtained chlorinated polyvinyl chloride resin is 67.8 percent (weight ratio), the dry powder fluidity is 40s, and the obtained product has tensile elasticity for testing performanceThe modulus is 2289MPa, the tensile strength is 55MPa, and the impact strength of the simply supported beam is 13kJ/m2。
Comparative example 1 added initiator, need to pass the infiltration process at the same time, initial temperature and final temperature are higher than this invention, chlorine introduction, temperature rise control and pressure control are different from this invention in chlorination reaction, chlorinated polyvinyl chloride resin prepared by it, the dry powder fluidity is not good, tensile elastic modulus is low, the rigidity is reduced, the impact strength of the simple beam is also reduced, meanwhile, chlorination reaction time is 3.86 h.
Claims (3)
1. A preparation method of chlorinated polyvinyl chloride is characterized by comprising the following steps: the preparation method comprises the following steps: preparing a suspension solution and performing chlorination reaction; the chlorination reaction comprises a first-stage chlorination and a second-stage chlorination;
the chlorination reaction has the initial reaction temperature of 40-50 deg.c, the reaction terminating temperature of 80-100 deg.c and the chlorine introducing amount to PVC resin weight ratio of 0.4-0.9;
the first-stage chlorination is characterized in that chlorine gas is uniformly introduced from the initial temperature, the chlorine gas introduction and the temperature rise are carried out simultaneously, when the chlorine introduction time is 1.5h, the pressure in the kettle reaches the set pressure, the chlorine introduction amount reaches 50% -80% of the total chlorine introduction amount, and the reaction temperature is 80% -98% of the termination temperature;
the set pressure is 0.3-0.4 MPa;
in the first stage of chlorination, the heating rate is 1.5-2 ℃/5 min;
in the second stage, chlorination is carried out, the temperature is raised at a constant speed, chlorine is continuously introduced, and the reaction pressure is kept constant at a set pressure;
in the second stage of chlorination, the heating rate is 0.5-1.2 ℃/5min, and the reaction time is 35-60 min;
preparing a suspension solution, adding a hydrochloric acid solution, PVC resin, a dispersing agent and an anti-sticking agent, and uniformly stirring to prepare the suspension solution; the mass concentration of the hydrochloric acid solution is 16-21%;
the dosage of the dispersing agent is 0.02-1.0% of the PVC resin, the dosage of the anti-sticking agent is 0.08-1.6% of the PVC resin, and the weight ratio of the PVC resin to the hydrochloric acid solution is 1:3-1: 9.
2. The process for the preparation of chlorinated polyvinyl chloride according to claim 1, characterized in that: the polymerization degree of the raw material PVC resin is 500-2500; the average particle size ranges from 160 μm to 230 μm, and the apparent density ranges from 0.55g/ml to 0.65 g/ml.
3. The process for the preparation of chlorinated polyvinyl chloride according to claim 1, characterized in that:
the dispersing agent is one or two of sodium dodecyl benzene sulfonate, sodium polymethacrylate, polyvinylpyrrolidone and polyether surfactant;
the anti-sticking agent is one of talcum powder, silicon dioxide and silicone oil.
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| KR20160140619A (en) * | 2014-03-31 | 2016-12-07 | 세키스이가가쿠 고교가부시키가이샤 | Production method for chlorinated vinyl chloride resin |
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