Dynamic regulation and control method for producing PVC (Polyvinyl Chloride) resin by polymerization kettle, PVC resin and application of PVC resin to preparation of transparent product

Abstract

The invention discloses a dynamic regulation and control method for producing PVC (polyvinyl chloride) resin in a polymerization kettle, the PVC resin and application. Energy waste and generation of side reaction products are reduced through regulation and control of the dynamic initiator, and the reaction rate and the stability of product quality are improved; through gradient collaborative optimization of the dispersing agent, the dispersion effect of PVC resin particles is improved, and particle aggregation is reduced, so that the optical performance of downstream sheet products is improved; and a multivariable closed-loop linkage adjustment mechanism is utilized, so that the number of unstable structures in a molecular chain is reduced, the weather resistance and yellowing resistance of downstream sheet products are improved, and intelligentization and high efficiency of production are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of PVC resin polymerization reaction, in particular to a dynamic control method for producing PVC resin in a polymerization kettle and the application of the PVC resin and the PVC resin in preparing transparent products. Background Art

[0002] In the traditional PVC production process for transparent sheets, the polymerization system formula and process parameters are statically set and cannot be dynamically adjusted according to the reaction state, which easily leads to particle agglomeration. There is no dynamic correlation between the initiator dosage and the reaction rate, and the initiator waste rate is high (≥15%). The circulating water fluctuates by more than ±20%. These changes in factors lead to an unstable reaction system, which ultimately affects the product transparency, mechanical properties and production efficiency.

[0003] In existing technologies, dispersant ratios are fixed, and initiator dosage adjustments lack a dynamic response mechanism. This results in large fluctuations in circulating water usage, high energy consumption, and insufficient product uniformity. Existing technologies, such as the PVC formulation disclosed in patent publication number CN111333758A, use traditional dispersant components without integrating real-time monitoring data for process optimization. While patent publication number CN108976335A mentions closed-loop control, it fails to address the dynamic matching issues associated with multivariable coupling, resulting in insufficient process stability. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a dynamic control method for producing PVC resin in a polymerization kettle and the application of PVC resin and the use thereof in preparing transparent products, thereby improving the mechanical and optical properties of PVC products.

[0005] In the first aspect, the present invention provides a method for dynamic control of PVC resin production in a polymerization reactor, characterized by comprising dynamic initiator control, dispersant gradient coordinated optimization and linkage regulation, wherein:

[0006] Dynamic initiator regulation:

[0007] The circulating water flow, temperature and reaction rate in the polymerization kettle are monitored in real time by sensors. The real-time and historical data are used to establish an adaptive matching model between initiator dosage and reaction rate, and the initiator dosage is dynamically adjusted.

[0008] Dispersant Gradient Collaborative Optimization:

[0009] S1, monitor the particle size distribution of materials in the reactor and collect real-time DLS data stream;

[0010] S2. Perform decentralized status evaluation on the collected data stream:

[0011] When the aggregation index is less than 0.7, the particle size distribution is stable, the existing reaction parameters are maintained unchanged, and the polymerization reaction is completed;

[0012] When the aggregation index is ≥0.7 and the particle size distribution is unstable, a dispersant gradient is added in a coordinated manner. After the dispersant is added, steps S2-1 and S2-2 are repeated until the particle size distribution is stable.

[0013] Linkage adjustment: Real-time monitoring of the oxidation state and pH of the reaction system in the polymerization reactor, and linkage adjustment of the dosage of buffer and antioxidant.

[0014] Furthermore, the sensors used in dynamic initiator control include flow sensors, temperature sensors and reaction rate monitors. The flow sensors are installed at the inlet and outlet pipes of the circulating water of the polymerization kettle, the temperature sensors are distributed at different heights on the inner wall of the polymerization kettle, and the reaction rate monitor is integrated above the agitator blades of the polymerization kettle at 0.2 to 0.7 times the kettle diameter, with a radial range of 1000 mm to 1800 mm and a cutting angle of 0°±3°. A fiber optic free radical probe is used to detect the free radical concentration in real time.

[0015] Furthermore, the adaptive matching model is a nonlinear relationship model between the initiator dosage X and the reaction rate Y established based on the polymerization reaction time;

[0016] The established model expression is:

[0017] Y=f(X,T,Q)+∈ Y

[0018] Y=0.0148×√X×exp[8.86-2986.195 / (T+273)]+0.0026Q+∈Y

[0019] Wherein, Y is the reaction rate (% / min), X is the amount of initiator (ppm), T is the reaction temperature (°C), Q is the circulating water flow rate (maximum about 500-600m 3 / h), ∈Y is the error correction term (±0.05% / min), which is used to consider the impact of random factors or system conditions not included in the model on the reaction rate.

[0020] Furthermore, the conditions for particle size data collection and selection in the collaborative optimization of dispersant gradient are as follows: automatic sampling every 5 to 20 minutes, and calculation of D10, D50, D90, and D[4, 3] values ​​through scattered light intensity analysis of the online particle size analyzer; and elimination of abnormal values ​​caused by interference from bubbles or impurities.

[0021] Furthermore, the dispersant is divided into a main dispersant, an auxiliary dispersant and a reactive dispersant. The main dispersant is added before the polymerization reaction begins, the auxiliary dispersant is added in the early stage of the reaction, and the reactive dispersant is introduced in the middle stage of the reaction.

[0022] Furthermore, the main dispersant is a polymer dispersant; and / or the auxiliary dispersant is one or more of an inorganic nanomaterial dispersant, a functional surfactant, and a bio-based dispersant; and / or the reactive dispersant is a double-bond modified dispersant.

[0023] Furthermore, the monitoring parameters include pH value and free radical concentration, when the pH value deviates from the range, the buffer is added; when the free radical concentration exceeds the standard, the antioxidant is added; and / or, the pH value range is 6.5-7.5, the free radical concentration threshold range is 10 -9 ~10 -3 mol / L.

[0024] Furthermore, the buffer is any one or more of sodium bicarbonate, ammonium bicarbonate, and sodium hydroxide; and / or the antioxidant is any one of hindered phenol antioxidants, phosphite antioxidants, and thioester antioxidants.

[0025] In a second aspect, the present invention provides a PVC resin prepared by the above method, which has uniform particle size, particle size distribution concentration <0.7, particle size 130μm±5μm, aging 10 ...

[0026] In a third aspect, the present invention provides an application of the above-mentioned PVC resin, wherein the above-mentioned PVC resin is used to prepare a PVC sheet having a thickness of 1 to 10 mm, a tensile strength ≥50 MPa, a light transmittance ≥92.5%, and a haze ≤2.8%.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) Reduce energy waste and side reaction product generation through dynamic initiator regulation, and improve reaction rate and product quality stability;

[0029] (2) The dispersion effect of PVC resin particles is improved through the coordinated optimization of dispersant gradient, which reduces particle agglomeration and thus improves the optical properties of downstream sheet products;

[0030] (3) The use of a multi-variable closed-loop linkage adjustment mechanism reduces the number of unstable structures in the molecular chain, improves the weathering and yellowing resistance of downstream sheet products, and realizes intelligent and efficient production;

[0031] (4) The present invention makes the PVC resin particles uniform in size, with a distribution concentration of less than 0.7, a particle size of 130 μm ± 5 μm, an aging whiteness of more than 85, and a thermal stability time of more than 5 minutes, and improves the optical properties (light transmittance ≥ 92%, haze ≤ 3%) and mechanical properties (tensile strength ≥ 50 MPa) of the PVC sheet during processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A process flow chart for collaborative optimization of dispersant gradient in the dynamic control method for producing PVC resin in a polymerization kettle provided by the present invention;

[0033] Figure 2 This is a schematic diagram of the linkage adjustment of the polymerization kettle provided by the present invention for producing PVC resin. DETAILED DESCRIPTION

[0034] In order to fully understand the purpose, features and effects of the present invention, the present invention is described in detail through the following specific embodiments, but the present invention is not limited thereto.

[0035] Flow sensors are installed at the circulating water inlet and outlet pipes of the polymerization kettle to monitor the real-time changes in the circulating water flow rate. Several temperature sensors are distributed at different heights (such as the upper, middle and lower layers) on the inner wall of the polymerization kettle to monitor the temperature distribution of the reaction system in real time. The polymerization kettle is equipped with a stirrer with blades, and the reaction rate monitor is integrated at 0.2 to 0.7 times the diameter of the kettle above the stirrer blades, with a radial distance of 1000mm to 1800mm and a bevel angle of 0°±3°. A fiber optic free radical probe is used to detect the free radical concentration in real time. The flow sensor, temperature sensor and reaction rate monitor are all connected to the central control system in communication, and the detected data is transmitted to the central control system. The system establishes an adaptive matching model of initiator dosage and reaction rate based on historical data and real-time data, and dynamically adjusts the initiator dosage. Preferably, the central control system uses an industrial computer equipped with an adaptive matching model (based on a machine learning algorithm, and the training data is historical process data and real-time monitoring data). The accuracy of the flow sensor is ±1%, and the accuracy of the temperature sensor is ±0.5℃.

[0036] The present invention provides a method for dynamically controlling PVC resin in a polymerization reactor, comprising the following steps:

[0037] Dynamic initiator regulation:

[0038] The real-time monitoring data of the flow sensor, temperature sensor and reaction rate monitor are all transmitted to the central control system. The central control system establishes an adaptive matching model between initiator dosage and reaction rate based on historical data and real-time data, and dynamically adjusts the initiator dosage.

[0039] (1) Establishment of adaptive matching model:

[0040] Data preparation: Collect historical data, including circulating water flow (Q), temperature (T), reaction rate (Y), and the corresponding real-time initiator addition amount (X). Simultaneously, real-time data is collected through flow sensors, temperature sensors, and reaction rate monitors to provide data support for subsequent real-time optimization.

[0041] Model selection: A learning algorithm based on polymerization reaction time is used to establish a nonlinear relationship model between initiator dosage (X) and reaction rate (Y).

[0042] Model expression:

[0043] The established model expression is:

[0044] Y=f(X,T,Q)+∈ Y

[0045]

[0046] Wherein, Y is the reaction rate (% / min), X is the amount of initiator (ppm), T is the reaction temperature (°C), Q is the circulating water flow rate (maximum about 500-600m 3 / h), ∈Y is the error correction term (±0.05% / min), which is used to consider the impact of random factors or system conditions not included in the model on the reaction rate.

[0047] Real-time optimization: By analyzing historical data, the estimated values ​​of parameters such as initiator dosage, temperature, circulating water flow, and the corresponding error covariance matrix are initialized to evaluate and optimize the model parameters.

[0048] When the circulating water flow rate fluctuates by more than ±10%, the system immediately triggers the initiator gradient adjustment (±0.5kg / time), with a response time of ≤10 minutes. After the circulating water flow rate returns to normal, the reaction process continues to be controlled according to the model.

[0049] (2) Synergistic optimization of dispersant gradient, e.g. Figure 1 shown.

[0050] Dynamic light scattering technology is used to monitor particle size distribution data online. The system evaluates the dispersion state of the collected data stream and takes different measures to add dispersants with different functions to build a gradient dispersion network. Each dispersant component plays a role at different stages, inhibiting PVC particle agglomeration and improving particle dispersion uniformity. The specific steps are:

[0051] S1, monitor the particle size distribution of materials in the reactor and collect real-time DLS data stream;

[0052] S2. Perform decentralized status evaluation on the collected data stream:

[0053] When the conversion rate matches the particle size distribution and the aggregation index is less than 0.7, it indicates that the particle morphology is stable, the existing reaction parameters are maintained unchanged, and the polymerization reaction is completed;

[0054] When the conversion rate does not match the particle size distribution and the aggregation index is ≥0.7, it indicates that the particle morphology is unstable. A dispersant gradient is added in a coordinated manner. Auxiliary dispersants and reactive dispersants are added according to the reaction stage. After the dispersant is added, steps S2-1 and S2-2 are repeated until the particle size distribution is stable.

[0055] Specifically, an online particle size analyzer is used, and its accompanying online sampling device is integrated above the polymerization reactor agitator blade at 0.2 to 0.7 times the reactor diameter (radial range 1000 mm to 1800 mm, bevel angle 0° ± 3°). The detectors are positioned uniformly or symmetrically. This area is the turbulent zone where the materials are most evenly mixed, ensuring the overall representativeness of the sample. The optical signal of individual particles is detected to monitor the particle size distribution of PVC particles in the reaction system in real time (range: 5 μm to 500 μm). Particle size data collection and selection conditions: Automatic sampling every 5 to 20 minutes, and calculation of D10, D50, D90, and D[4,3] (volume particle size) values ​​through scattered light intensity analysis; outliers caused by air bubbles or impurities are eliminated (threshold: scattering intensity fluctuation of more than ±5%).

[0056] Dispersants are divided into primary dispersants, auxiliary dispersants and reactive dispersants according to their functions:

[0057] Primary dispersant: It prevents droplet aggregation through steric hindrance effect and is a polymer dispersant such as polyvinyl alcohol (PVA) and hydroxypropyl methylcellulose (HPMC).

[0058] Auxiliary dispersants: adjust interfacial tension and droplet size distribution, and form a synergistic effect with the main dispersant, such as inorganic nanomaterials, functional surfactants, and bio-based dispersants.

[0059] Preferably, inorganic nanomaterials include nano-silicon dioxide, nano-zinc oxide, nano-aluminum oxide, carbon nanotubes, graphene / alkyne quantum dots, etc.

[0060] Preferred functional surfactants include polyether-modified silicones (polyether-modified heptamethyltrisiloxane, bis-hydroxyethoxypropyl polydimethylsiloxane, polyether silicone copolymers), and fluorocarbon surfactants (perfluorooctyl polyether, perfluorooctyl sulfonyl fluoride, heptadecafluoro-1-octane sulfonyl fluoride).

[0061] Preferred bio-based dispersants: chitosan derivatives.

[0062] Reactive dispersants: Double-bond modified dispersants, which enhance interfacial stability through chemical bonding, such as mercapto-modified polyvinyl alcohol and polyurethane methacrylate.

[0063] Gradient addition strategy: add the main dispersant (0.5wt%~2.0wt%) before the start of the reaction, supplement the auxiliary dispersant (0.05wt%~0.35wt%) in the early stage of the reaction (conversion rate 10%~30%), and introduce the reactive dispersant (0.01wt%~0.15wt%) in the middle stage of the reaction (conversion rate 30%~50%).

[0064] (3) Linkage regulation (closed-loop regulation of buffers and antioxidants), such as Figure 2 shown.

[0065] By monitoring the oxidation state and pH of the reaction system in real time, the amount of buffer and antioxidant added is dynamically adjusted. The antioxidant dosage is automatically adjusted based on changes in free radical concentration during the reaction, while the buffer maintains the stability of the reaction environment, achieving a synergistic effect between the two.

[0066] Monitoring parameters include pH, free radical concentration (electrochemical sensor method) and temperature; the normal pH range is 6.5-7.5, and the free radical concentration threshold is 0.1 mol / L.

[0067] The buffer is any one of sodium bicarbonate, ammonium bicarbonate, and sodium hydroxide; the antioxidant is any one or more of hindered phenols, hindered amines, phosphites, and thioesters, wherein hindered phenols include 2,6-di-tert-butyl-4-methylphenol and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; phosphites include tris(2,4-di-tert-butylphenyl)phosphite; and thioesters include distearyl thiodipropionate.

[0068] When the pH deviates from the range, the buffer is automatically adjusted within a range of ±0.05% to 0.1%. When the free radical concentration exceeds the standard, the dosage of antioxidant is increased in batches within a range of ±0.01% to 0.05%.

[0069] Through linkage regulation, the number of unstable structures in the molecular chain is reduced, and the weather resistance and anti-yellowing performance of the transparent sheet are improved.

[0070] Example 1:

[0071] (1) Implementation of dynamic initiator control: A flow sensor (accuracy ±1%), a temperature sensor (accuracy ±0.5°C), and an online reaction rate monitor were installed in the polymerization reactor. The central control system used an industrial computer equipped with an adaptive matching model (based on a machine learning algorithm, with training data consisting of historical process data and real-time monitoring data).

[0072] The initial initiator dosage was 5 kg, and the reaction rate was 0.8% / min.

[0073] When real-time monitoring of circulating water flow fluctuations exceeding ±10%, the system triggers an adjustment mechanism, adjusting the initiator dosage by a gradient of ±5kg / time, with a response time of ≤10 minutes. After the adjustment, the reaction rate stabilizes at 0.85% / min, the circulating water flow fluctuations drop to ±5%, and the adaptive matching model is restored to control the reaction parameters.

[0074] The initiator waste rate was reduced from 15% to 5%, the transmittance of downstream sheet products increased to 92.5%, and the haze was reduced to 2.8%.

[0075] (2) Dispersant gradient collaborative optimization

[0076] The polymerization reaction temperature is 68°C, the stirring speed is set to 70 r / min, the initial dispersant dosage is 1.5 wt%, and in the early stage of the reaction (conversion rate 10% to 30%), the particle size is 80 μm ± 10 μm, the aggregation index is <0.7, the monitored particle size state is stable, and the existing parameters are maintained unchanged to complete the polymerization reaction.

[0077] The polymerization reaction temperature is 68°C, the stirring speed is set to 50r / min, the initial dispersant dosage is 0.5wt%, and in the early stage of the reaction (conversion rate 10% to 30%), the particle size is 100μm±10μm, the aggregation index is ≥0.7, the monitored particle size distribution is unstable, 0.05wt% to 0.35wt% of the auxiliary dispersant solution is added, and the particle size change is continuously monitored. In the middle stage of the reaction (conversion rate 30% to 50%), the particle size is stable at 120μm±10μm, the aggregation index is <0.7, the particle size state is stable, the existing parameters are maintained unchanged, and the polymerization reaction is completed.

[0078] The polymerization reaction temperature is 68.1°C, the stirring speed is set to 90r / min, the initial dispersant dosage is 2.0wt%, in the early stage of the reaction (conversion rate 10%~30%), the particle size is 75μm±10μm, the aggregation index is>0.7, the monitoring particle size distribution is unstable, 0.05wt%~0.35wt% of the auxiliary dispersant solution is added, and the particle size change is continuously monitored. In the middle stage of the reaction (conversion rate 30%~50%), the particle size is stable at 120μm±10μm, the aggregation index is>0.7, and 0.01wt%~0.15wt% of the reactive dispersant is added in the secondary stage. The particle size of 50% conversion rate is tested to be 135μm±10μm, the aggregation index is <0.7, the particle size state is stable, the existing parameters are maintained unchanged, and the polymerization reaction is completed.

[0079] The primary dispersant (polyvinyl alcohol) is used in an amount of 0.6 wt% of the total mass of the raw materials in the polymerization kettle; the auxiliary dispersant is nano-silicon dioxide (particle size 20 nm), used in an amount of 0.05 wt% of the total mass of the raw materials in the polymerization kettle; and the reactive dispersant is a double-bond modified dispersant, used in an amount of 0.05 wt% of the total mass of the raw materials in the polymerization kettle. The water-oil ratio is controlled to be 1:1-3, and the packing coefficient is 0.70-0.85.

[0080] The agglomeration rate of PVC particles is reduced by 60% compared with the existing technology. The particle size is uniform, the distribution concentration is below 0.7, and the finished product particle size is 130μm±5μm.

[0081] (3) Multivariable closed-loop linkage regulation

[0082] The pH value and free radical concentration (threshold 0.1 mol / L) of the polymerization reactor reaction system were monitored in real time.

[0083] When the pH deviates from the range (6.5-7.5), the buffer is automatically adjusted within a range of ±0.05% to 0.1%. When the free radical concentration exceeds the standard, the amount of antioxidant is increased in batches within a range of ±0.01% to 0.05%. Add by continuous dropwise addition or batch feeding.

[0084] The unstable structure of the molecular chain is reduced by 40%, the weather resistance of the product is improved, and the yellowing index is reduced from 2.25 to 1.12, a decrease of more than 50%.

[0085] The PVC resin prepared by the above method was tested according to GB / T 2913 "Test method for whiteness of plastics" and GB / T 2917.1 "Determination of hydrogen chloride and any other acidic products released by blends and products based on vinyl chloride homopolymers and copolymers at elevated temperatures - Congo red method." The thermal stability time was at least 5 minutes, and the aged whiteness was at least 85%.

[0086] Prepare PVC sheets with a thickness of 1 to 10 mm. Test the optical properties of the sheets in accordance with the group standard T / CCASC 3002-2023 "Polyvinyl Chloride Dynamic Thermal Stability Test - Double-Roller Mixing Method", with a light transmittance of ≥92% and a haze of ≤2.5%.

[0087] The sheet's mechanical properties were tested according to GB / T 1040, "Determination of Tensile Properties of Plastics." The sheet's tensile strength was increased to 52 MPa.

[0088] Finally, it should be noted that the above-listed embodiments are merely preferred embodiments of the present invention. Of course, those skilled in the art may make changes and modifications to the present invention. If these modifications and variations fall within the scope of the claims of the present invention and their equivalents, they should be considered to be within the scope of protection of the present invention.

Claims

1. A dynamic control method for producing PVC resin in a polymerization reactor, characterized in that: include: Dynamic initiator regulation: The circulating water flow, temperature and reaction rate in the polymerization kettle are monitored in real time by sensors. The real-time and historical data are used to establish an adaptive matching model between initiator dosage and reaction rate, and the initiator dosage is dynamically adjusted. Dispersant Gradient Collaborative Optimization: S1, monitor the particle size distribution of materials in the reactor and collect real-time DLS data stream; S2. Perform decentralized status evaluation on the collected data stream: When the aggregation index is less than 0.7, the particle size distribution is stable, the existing reaction parameters are maintained unchanged, and the polymerization reaction is completed; When the aggregation index is ≥0.7 and the particle size distribution is unstable, a dispersant gradient is added in a coordinated manner. After the dispersant is added, steps S2-1 and S2-2 are repeated until the particle size distribution is stable. Linkage adjustment: Real-time monitoring of the oxidation state and pH of the reaction system in the polymerization reactor, and linkage adjustment of the dosage of buffer and antioxidant.

2. The dynamic control method for producing PVC resin in a polymerizer according to claim 1, characterized in that: The sensors used in dynamic initiator control include flow sensors, temperature sensors and reaction rate monitors. The flow sensors are installed at the inlet and outlet pipes of the circulating water of the polymerization kettle. The temperature sensors are distributed at different heights on the inner wall of the polymerization kettle. The reaction rate monitor is integrated above the agitator blades of the polymerization kettle at 0.2 to 0.7 times the kettle diameter, with a radial range of 1000 mm to 1800 mm and a cutting angle of 0°±3°. A fiber optic free radical probe is used to detect the free radical concentration in real time.

3. The dynamic control method for producing PVC resin in a polymerizer according to claim 1, characterized in that: The adaptive matching model is a nonlinear relationship model between the initiator dosage X and the reaction rate Y established based on the polymerization reaction time; The established model expression is: Y=f(X,T,Q)+∈ Y Where Y is the reaction rate, % / min; X is the initiator dosage, ppm; T is the reaction temperature, °C; Q is the circulating water flow rate, with a maximum of approximately 500-600 m3 / h; ∈Y is the error correction term, ±0.05% / min, which is used to consider the impact of random factors or system conditions not included in the model on the reaction rate.

4. The dynamic control method for producing PVC resin in a polymerizer according to claim 1, wherein: The conditions for particle size data collection and selection in the collaborative optimization of dispersant gradient are as follows: automatic sampling every 5 to 20 minutes, calculation of D10, D50, D90, and D[4, 3] values ​​by scattered light intensity analysis of the online particle size analyzer; and elimination of abnormal values ​​caused by interference from bubbles or impurities.

5. The dynamic control method for producing PVC resin in a polymerizer according to claim 1, characterized in that: Dispersants are divided into main dispersants, auxiliary dispersants and reactive dispersants. The main dispersant is added before the polymerization reaction starts, the auxiliary dispersant is added in the early stage of the reaction, and the reactive dispersant is introduced in the middle stage of the reaction.

6. The dynamic control method for producing PVC resin in a polymerizer according to claim 5, characterized in that: The main dispersant is a polymer dispersant; and / or The auxiliary dispersant is one or more of an inorganic nanomaterial dispersant, a functional surfactant, and a bio-based dispersant; and / or Reactive dispersants are double bond modified dispersants.

7. The dynamic control method for producing PVC resin in a polymerizer according to claim 1, characterized in that: Linked adjustment of monitoring parameters including pH value and free radical concentration, when pH value deviates from the range, add buffer; when free radical concentration exceeds the standard, add antioxidant; and / or pH value range is 6.5~7.5, free radical concentration threshold range is 10 -9 ~10 -3 mol / L.

8. The dynamic control method for producing PVC resin in a polymerizer according to claim 1, characterized in that: The buffer is any one or more of sodium bicarbonate, ammonium bicarbonate, and sodium hydroxide; and / or The antioxidant is any one of hindered phenol antioxidants, phosphite antioxidants, and thioester antioxidants.

9. The high-transmittance PVC resin obtained by the method for dynamically controlling the production of PVC resin in a polymerization reactor according to any one of claims 1 to 8, characterized in that: The particle size is uniform, the particle size distribution concentration is less than 0.7, the particle size is 130μm±5μm, the aging whiteness is ≥85, and the thermal stability time is ≥5min.

10. An application of high light transmittance PVC resin, characterized in that: The high-transmittance PVC resin according to claim 9 is used to prepare a transparent PVC sheet product, wherein the PVC sheet has a thickness of 1 to 10 mm, a tensile strength of 50 MPa or more, a transmittance of 92.5% or more, and a haze of 2.8% or less.

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