阅读说明：本技术 一种5万吨级产能规模以上的透明聚苯乙烯及其生产设备、工艺 (Transparent polystyrene with capacity of more than 5 ten thousand tons and production equipment and process thereof ) 是由 兰司 赵加昱 曹之勇 芮元庆 宋愚 于 2020-12-28 设计创作，主要内容包括：本发明公开了一种5万吨级产能规模以上的透明聚苯乙烯及其生产设备、工艺。本发明获得的透明聚苯乙烯产品的主要成分为式中n为聚合度,其范围在600-7000不等,随产品的类不同而不同。该透明聚苯乙烯,具有良好的透明性,维卡软化点在85-106摄氏度,常温下其拉伸强度为40-55Mpa,是一种热塑性材料。分子结构中含少量的特种结构大分子并且在大分子的间隙含有相当数量的烃类小分子使大分之间能够产生一定的滑移,使材料相比于其他工艺生产方法所得的产品具有良好透明和力学性能。生产过程中基本不产生工艺废水,所有的原料均回收循环利用,产生的少量工艺废气通过冷凝及专用设备吸附处理后达标排放,能达到良好的环境友好和节能降耗的效果。(The invention discloses transparent polystyrene with the capacity of more than 5 ten thousand tons and production equipment and a process thereof. The main component of the transparent polystyrene product obtained by the invention is Wherein n is the degree of polymerization, and the range of n is 600-7000, which varies with the product type. The transparent polystyrene has good transparency, the Vicat softening point is 85-106 ℃, the tensile strength is 40-55Mpa at normal temperature, and the transparent polystyrene is a thermoplastic material. The molecular structure contains a small amount of macromolecules with special structures and a considerable amount of hydrocarbon micromolecules in gaps among the macromolecules, so that certain slippage can be generated among the macromolecules, and the material is produced compared with other processesThe product obtained by the production method has good transparency and mechanical property. The production process does not basically generate process wastewater, all raw materials are recycled, and a small amount of generated process waste gas is subjected to condensation and adsorption treatment by special equipment and then is discharged after reaching standards, so that good effects of environmental friendliness, energy conservation and consumption reduction can be achieved.)

1. The equipment is characterized by comprising a TBC remover communicated with a styrene raw material feeding pipeline, a styrene feeding preheating and pre-polymerization reaction device, a styrene post-polymerization reaction device, a polymer preheating and two-stage devolatilization device, an unreacted monomer recovery device and a polymer particle cutting and drying device which are sequentially connected through pipelines; the styrene preheating and pre-polymerization reaction device comprises a styrene monomer feeding preheater, a pre-polymerization kettle top reflux condenser and a pre-polymerization polymer delivery pump, and is connected with the styrene post-polymerization reaction device; the styrene post-polymerization reaction device comprises a first post-polymerization kettle and a second post-polymerization kettle which are connected in series and have a stirring function, each post-polymerization kettle is respectively provided with a first post-polymerization kettle top reflux condenser, a second post-polymerization kettle top reflux condenser, a first post-polymerization polymer delivery pump and a second post-polymerization polymer delivery pump, and the second post-polymerization polymer delivery pump on the second post-polymerization kettle is connected with a polymer preheater; the polymer preheating and two-stage devolatilization device comprises a polymer preheater, a first devolatilization kettle and a second devolatilization kettle which are connected in sequence, wherein the first devolatilization kettle and the second devolatilization kettle are both provided with polymer delivery pumps, the delivery pump outlet pipeline of the polymer of the second devolatilization kettle is connected with a polymer granulating and drying device, and in addition, the first devolatilization kettle and the second devolatilization kettle are connected with an unreacted monomer recovery device; the unreacted monomer recovery device comprises a devolatilization condenser and a circulating liquid tank, and is provided with a recovery liquid pipeline for returning the recovery liquid to the styrene feeding preheating and prepolymerization reaction device.

2. The production facility of transparent polystyrene with capacity of 5 ten thousand tons or more as claimed in claim 1, wherein the TBC remover for styrene is a metal cylindrical metal container with elliptical heads at both ends, and has supporting plates inside, loading and unloading holes at the side for loading and unloading activated alumina, and material inlets and outlets at both ends for liquid material to enter and exit.

3. The apparatus for transparent polystyrene production with capacity of 5-million tons or more in scale according to claim 1, wherein the styrene preheating and prepolymerization reaction unit comprises a two-tube-pass tubular styrene feed preheater with a temperature control system and a prepolymerization reactor connected to the corresponding pipeline; the prepolymerization reactor is a kettle type reactor, is provided with an outer jacket and a stirring device, and has blades in the form of multilayer four-blade flat blades, multilayer four-blade inclined blades, multilayer two-blade flat blades, multilayer two-blade inclined blades, multilayer three-blade turbine blades, anchor blades, ribbon blades, screw blades or the combination of the above stirring blades; the operation type of the kettle type reactor is a fully mixed flow type and is provided with a kettle top reflux condenser, a material delivery pump, a temperature control system and a liquid level control system.

4. The production facility of transparent polystyrene having a capacity of 5-million tons or more as claimed in claim 1, wherein the postpolymerization apparatus is a tank reactor of a fully mixed flow type in which two tanks are connected in series by a pipeline; the full mixed flow type kettle reactor is provided with an outer jacket and a stirring device, the blade type of the full mixed flow type kettle reactor is a multilayer four-blade flat blade, a multilayer four-blade inclined blade, a multilayer two-blade flat blade, a multilayer two-blade inclined blade, a multilayer three-blade turbine blade, an anchor blade, a helical ribbon type blade, a screw type blade or a combination of the stirring type blades, and the full mixed flow type kettle reactor is matched with a kettle top reflux condenser, a material delivery pump, a temperature control system and a liquid level control system.

5. The production facility for transparent polystyrene with capacity of 5-ten-thousand-ton-scale or more according to claim 1, wherein the polymer preheating facility is a tubular heater suitable for heating high-viscosity materials with an inserted mixing element and provided with a corresponding temperature control system, and an operation device of a devolatilization unit consisting of a first devolatilization kettle and a second devolatilization kettle which are connected in series; the high-temperature and high-vacuum devolatilization kettle is a cylindrical container, wherein a lower end socket of a kettle body is provided with a jacket heated by high-temperature hot oil, a high-temperature oil external heating coil is welded outside a cylinder body, a melt feed port is arranged at the upper side part of the cylindrical container, a polymer distributor is arranged at the upper part of the cylinder body and is connected with the melt feed port, and the devolatilization kettle can resist the negative pressure operation of high temperature of 280 ℃ and high vacuum; two discharge ports are arranged at the bottom of the kettle and are connected with two polymer conveying pumps for conveying polymer melt outwards at high temperature; the polymer distributor is a long cylindrical cylinder with one closed end, overflow port in the upper part and holes in the lower part in certain diameter, amount and interval, and is installed horizontally to the upper part of the devolatilization reactor.

6. The apparatus for transparent polystyrene production with capacity of 5 ten-thousand tons or more according to claim 1, wherein the recovery unit of the unreacted monomer is a unit operation unit comprising a tubular devolatilization condenser, a vacuum pump set, a recycle liquid tank and a recycle liquid pump and having the functions of evacuating, condensing ethylbenzene/styrene, storing and delivering the recycle liquid, and is used for recycling the unreacted styrene and feeding it to the prepolymerization apparatus.

7. The production facility for transparent polystyrene with capacity of 5-million tons or more of claim 1, wherein the polymer pellet drying device is a combination of a pelletizer, a drying fan and a tail gas dust filter, and the melt output from the second devolatilizer through the polymer pump is cut into finished particles with a size suitable for packaging, storage and transportation through good matching with the polymer pump.

8. A production process based on the device of any one of claims 1 to 7, characterized in that the process comprises the following specific steps:

adding the main raw materials into a prepolymerization kettle, fully and uniformly mixing under the condition of continuous stirring, carrying out prepolymerization reaction at the reaction temperature of 80-130 ℃ of the prepolymerization kettle to reach a certain conversion rate, then sequentially conveying the reaction products to a first post polymerization kettle and a second post polymerization kettle by using a pump for reaction, and removing the reaction heat in the polymerization process through a kettle top reflux condenser on each kettle so as to ensure that a polymer with a specific polymerization degree is obtained at a specific reaction temperature required by the process; the total conversion rate is improved to 80% through the reaction of three kettles connected in series, then the polymer is heated to above 235 ℃ through a polymer preheater and enters a first devolatilization kettle, and most of unreacted monomers and solvent ethylbenzene are removed from the polymer at high temperature and high vacuum of less than 3 kPa; then conveying the polymer subjected to primary devolatilization to a second devolatilization device by a pump, still maintaining high temperature and high vacuum <2kPa, and reducing the content of residual volatile organic matters in the materials to be below 800 ppm; and then filtering the polymer, conveying the polymer to a granulator die head for extrusion and bracing, granulating and drying to obtain a polystyrene product, and collecting unreacted monomers and solvents and returning the monomers and solvents to the prepolymerization kettle for recycling.

9. A transparent polystyrene prepared on the basis of the apparatus of any one of claims 1 to 7, characterized in that the polystyrene is

A. Styrene: purity is more than 99.9%, colorless transparent liquid, dosage is 0.960-0.990;

B. industrial white oil: the flash point is higher than 240 ℃, and the dosage of the colorless transparent liquid is 0.001-0.040;

C. internal and external lubricants: paraffin, zinc stearate, calcium stearate, stearic acid amide and oleic acid amide, wherein the appearance of the lubricant is white particles or powder, the purity of the lubricant is more than 99.8 percent, and 2 or more than 2 additives in the lubricant are selected for compound use: the dosage is 0.001-0.005;

D. antioxidant: BHT, Irganox1076, Irganox1010, Irganox 1330: one of the components is selected, and the dosage is 0.001-0.010;

E. oil-soluble blue pigment violet: the dosage is 10-50 ppm;

F. ultraviolet absorbers and light stabilizers: tinuvin327, Tinuvin UVP, Tinuvin320, Tinuvin328, Tinuvin770 and Tinuvin622, and more than 2 ultraviolet absorbers and light stabilizers are compounded according to different product requirements and specification grades: the addition amount is 0.0001-0.005;

G. organic peroxide initiator: tert-butyl peroxybenzoate; t-butyl peroxypivalate; 1. 1 di-tert-butylperoxy-3, 5 trimethylcyclohexane; 1. 1 di-tert-butylperoxy-cyclohexane; tert-butyl peroxynonanoate, compounded with 2 initiators according to different product requirements and specification grades: the addition amount is 0.0001-0.001;

H. ethylbenzene: purity > 99.9%, and addition amount of 0.001-0.09.

Technical Field

The invention relates to the technical field of polystyrene materials, in particular to transparent polystyrene with the capacity of more than 5 ten thousand tons and production equipment and a process thereof.

Background

Polystyrene refers to a polymer synthesized from styrene monomer by free radical addition polymerization. Because of the characteristics of hard polystyrene, good rigidity, easy processing and forming, stable size, insulation and the like, and low price, the polystyrene is widely applied to the industries of light industry markets, packaging, electric industry, toys, buildings and the like. However, general-purpose polystyrene also has the disadvantage of being not impact resistant, which limits its use. Currently, the production of polystyrene uses an initiator to increase the polymerization rate and adjust the molecular weight distribution of the polymer to produce high-quality polystyrene. According to the practical production application experience, the product produced by the initiator technology has better optical property, mechanical property and temperature resistance, and can produce products with lower melting index, improve the productivity of a production line, improve the conversion rate and reduce the energy consumption. The transparent polystyrene is used for manufacturing light guide plates and diffusion plates of televisions and liquid crystal displays, extrusion application of large transparent advertising boards, high-end application of injection molding materials of large refrigerator internals with high strength and temperature resistance requirements and the like. The applications have higher requirements on the temperature resistance, the mechanical property and the optical property of the polystyrene material, and the transparency and the mechanical property of the currently produced polystyrene can not meet the requirement of the industry on high-quality transparent polystyrene products. In order to solve the problem, the research and development of new formula, new process and new technology are very meaningful.

Disclosure of Invention

The invention aims to realize the mass production of polystyrene with good optical performance and excellent mechanical performance, and provides transparent polystyrene with the capacity of more than 5 ten thousand tons and production equipment and process thereof.

The above-mentioned invention is realized by using the following formula, equipment and technological process:

transparent polystyrene (GPPS) with the capacity of more than 5 ten thousand tons and the specific formula is as follows:

A. styrene: purity is more than 99.9%, and dosage is 0.960-0.990.

B. Industrial white oil: the flash point is more than 240 ℃, and the dosage is 0.001-0.040.

C. Internal and external lubricants: paraffin, zinc stearate, calcium stearate, stearic acid amide, oleic acid amide, etc. in the form of white granule or powder, with purity higher than 99.8% and dosage of 0.001-0.005.

D. Antioxidant: BHT, Irganox1076, Irganox1010, Irganox1330, etc., in an amount of 0.0001-0.010.

E. Oil-soluble blue pigment (violet): the dosage is 10-50 ppm.

F. Ultraviolet absorbers and light stabilizers: tinuvin327, Tinuvin UVP, Tinuvin320, Tinuvin328, Tinuvin770, Tinuvin622, addition amount: 0.0001-0.005.

G. Organic peroxide initiator: tert-butyl peroxybenzoate; t-butyl peroxypivalate; 1. 1 di-tert-butylperoxy-3, 5 trimethylcyclohexane; 1. 1 di-tert-butylperoxy-cyclohexane; tert-butyl peroxynonanoate, etc., in an amount of 0.0001-0.005.

H. Ethylbenzene: purity > 99.9%, and addition amount of 0.001-0.09.

The equipment comprises a TBC remover communicated with a styrene raw material feeding pipeline, a styrene feeding preheating and pre-polymerization reaction device, a styrene post-polymerization reaction device, a polymer preheating and two-stage devolatilization device, an unreacted monomer recovery device and a polymer granulation drying device which are sequentially connected through pipelines; the styrene preheating and prepolymerization reaction device comprises a feeding preheater, a prepolymerization reactor kettle top reflux condenser and a prepolymerization polymer delivery pump, and is connected with the styrene post-polymerization reaction device; a feeding filter is arranged between the TBC remover and the feeding preheater, and in addition, the prepolymerization kettle is also connected with a dehydration tank, a water cutting tank and a hot oil circulating pump; the styrene post-polymerization reaction device comprises a first post-polymerization kettle and a second post-polymerization kettle which are connected in series and have a stirring function, each post-polymerization kettle is respectively provided with a first post-polymerization kettle top reflux condenser, a second post-polymerization kettle top reflux condenser, a first post-polymerization polymer delivery pump and a second post-polymerization polymer delivery pump, and the second post-polymerization polymer delivery pump on the second post-polymerization kettle is connected with a polymer preheater; the polymer preheating and two-stage devolatilization device comprises a polymer preheater, a first devolatilization kettle and a second devolatilization kettle which are sequentially connected, wherein the first devolatilization kettle and the second devolatilization kettle are both provided with polymer delivery pumps, an outlet pipeline of the polymer delivery pump of the second devolatilization kettle is connected with a polymer granulating and drying device, in addition, the first devolatilization kettle and the second devolatilization kettle are connected with an unreacted monomer recovery device, and a polymer filter is arranged between the polymer granulating and drying device and the polymer preheating and two-stage devolatilization device; the unreacted monomer recovery device comprises a devolatilization condenser and a circulating liquid tank, and is provided with a recovery liquid pipeline for returning the recovery liquid to the styrene feeding preheating and prepolymerization reaction device.

Furthermore, the TBC remover for styrene feeding is a metal cylindrical metal container with elliptical seal heads at two ends, a supporting plate is arranged in the metal cylindrical metal container, loading and unloading holes for filling or unloading activated alumina are formed in the side surface of the metal cylindrical metal container, and material inlets and material outlets are formed at two ends of the metal cylindrical metal container and used for feeding and discharging liquid materials.

Further, the styrene preheating and prepolymerization reaction device comprises a double-tube-pass tubular styrene feeding preheater with a temperature control system and a prepolymerization reactor (a CSTR kettle type reactor) connected with an application pipeline; the prepolymerization reactor is a kettle type reactor, is provided with an outer jacket and a stirring device, and has blades in the form of multilayer four-blade flat blades, multilayer four-blade inclined blades, multilayer two-blade flat blades, multilayer two-blade inclined blades, multilayer three-blade turbine blades, anchor blades, ribbon blades, screw blades or the combination of the above stirring blades; the operation type of the kettle type reactor is a fully mixed flow type and is provided with a kettle top reflux condenser, a material delivery pump, a temperature control system and a liquid level control system.

Further, the post-polymerization reaction device is two full-mixed flow type kettle reactors connected in series by pipelines; the full mixed flow type kettle reactor is provided with an outer jacket and a stirring device, the blade type of the full mixed flow type kettle reactor is a multilayer four-blade flat blade, a multilayer four-blade inclined blade, a multilayer two-blade flat blade, a multilayer two-blade inclined blade, a multilayer three-blade turbine blade, an anchor blade, a helical ribbon type blade, a screw type blade or a combination of the stirring type blades, and the full mixed flow type kettle reactor is matched with a kettle top reflux condenser, a material delivery pump, a temperature control system and a liquid level control system.

Further, the polymer preheating facility is a tubular heater which is provided with a corresponding temperature control system and is internally inserted with a mixing element and suitable for heating high-viscosity materials, and an operating device of a devolatilization unit which is composed of a first devolatilization kettle and a second devolatilization kettle which are connected in series; the high-temperature and high-vacuum devolatilization kettle is a cylindrical container, wherein a lower end socket of a kettle body is provided with a jacket heated by high-temperature hot oil, a high-temperature oil external heating coil is welded outside a cylinder body, a melt feed port is arranged at the upper side part of the cylindrical container, a polymer distributor is arranged at the upper part of the cylinder body and is connected with the melt feed port, and the devolatilization kettle can resist the negative pressure operation of high temperature of 280 ℃ and high vacuum; two discharge ports are arranged at the bottom of the kettle and are connected with two polymer conveying pumps for conveying polymer melt outwards at high temperature; the polymer distributor is a long cylindrical cylinder with one closed end, the upper part of the polymer distributor is provided with a discharge hole, the lower part of the polymer distributor is provided with small holes with specific diameters, quantities and intervals according to the process requirements, the distributor is horizontally arranged at the upper part of the devolatilization kettle, and when the polymer passes through the distributor, the polymer can be well dispersed into a fine strip bundle shape and vertically falls to the bottom of the devolatilization kettle; in particular to a cylindrical cylinder which is provided with small round holes with the diameter of 2mm, the number of the round holes is 2000, the round holes are spaced 2mm, the diameter of the cylindrical cylinder is 250mm, and the length of the cylindrical cylinder is 2000 mm.

Further, the unreacted monomer recovery device is a unit operation device which is composed of a group of tube type devolatilization condensers, a vacuum pump set, a circulating liquid tank and a circulating liquid pump and has the functions of vacuumizing, condensing ethylbenzene/styrene, storing and conveying circulating liquid, and is used for recycling unreacted styrene and adding the unreacted styrene into the prepolymerization reaction device.

Furthermore, the polymer granulating and drying device comprises a granulator, a water material conveying tank, a dryer, a vibrating screen and a water circulation system, and the melt output by the polymer pump from the second devolatilization kettle is cut into finished product particles with sizes suitable for packaging, storage and transportation by matching with the polymer pump.

The production method comprises the following steps: the main raw material styrene monomer, various auxiliary agents such as white oil, stearate, initiator and the like, a recovered monomer and supplementary ethylbenzene are added into a prepolymerization kettle according to a proportion, the raw materials are fully and uniformly mixed under the condition of continuous stirring, prepolymerization reaction is carried out at a specific reaction temperature (80-130 ℃) of the prepolymerization kettle to reach a certain conversion rate, then the mixture is sequentially conveyed to a first post-polymerization kettle and a first post-polymerization kettle by a pump for reaction, and the reaction heat in the whole polymerization process is removed through a kettle top reflux condenser on each kettle so as to ensure that a polymer with a specific polymerization degree is obtained at the specific reaction temperature required by the process. The total conversion rate is improved to 80% by the reaction of three kettles in series, then the polymer is heated to above 235 ℃ by a polymer preheater and enters a first devolatilization kettle, and most of unreacted monomers and solvent ethylbenzene are removed from the polymer under high temperature and high vacuum (<3 kPa). The polymer from the first devolatilization was then pumped to a second devolatilizer, where the residual volatile organic content of the batch was reduced to below 800ppm while maintaining high temperature and high vacuum (<2 kPa). And then, filtering the polymer, conveying the polymer to a die head of a granulator for extrusion and bracing, granulating and drying to obtain the polystyrene product, and collecting unreacted monomers and solvent and returning the monomer and solvent to a prepolymerization kettle for recycling.

Compared with the prior art, the invention has the following remarkable advantages:

1. the process has the advantages of high production capacity, high reaction conversion rate, high production efficiency of the reaction kettle and low energy consumption;

2. the molecular weight and the distribution of the obtained product are easy to control, and the injection-grade product with wide molecular weight distribution or the extrusion-grade product with narrow molecular weight distribution can be flexibly adjusted according to the requirements of the product, so that various application requirements are met;

3. the product has low residual monomer, low content of oligomer and colored impurities and high product transparency, and can be used for producing high-end optical-grade GPPS for light guide plate and light diffusion plate;

4. the adopted technical process produces less waste water and waste gas and has good environmental protection effect; the production process is safe and controllable, and the danger is small.

Drawings

FIG. 1 is a block diagram of a general polystyrene GPPS production process and equipment with capacity of more than 5 ten thousand tons.

FIG. 2 is a simplified diagram of a general polystyrene GPPS production process and equipment for a capacity scale of 5 ten thousand tons.

FIG. 3 is a GPC measurement result chart of molecular weight and distribution.

1. A TBC remover; 2. a feed filter; 3. a feed preheater; 4. a prepolymerization kettle; 5. a reflux condenser at the top of the prepolymerization kettle; 6. a dehydration tank; 7. a water cutting tank; 8. a hot oil circulating pump; 9. a pre-polymerized polymer delivery pump; 10. a first post polymerizer; 11. a reflux condenser at the top of the first postpolymerization kettle; 12. a first post-polymerization polymer delivery pump; 13. a second postpolymerization kettle; 14. a second postpolymerization kettle top reflux condenser; 15. a second post-polymerization polymer delivery pump; 16. a polymer preheater; 17. a first devolatilization kettle; 18. a second devolatilization kettle; 19. a devolatilization condenser; 20. a circulating liquid tank; 21. a circulating liquid pump; 22. a polymer filter; 23. a granulator; 24 a dryer; 25. a drying fan; 26. tail gas dust filter.

Detailed Description

The invention will be further explained with reference to the drawings

The transparent polystyrene adopted by the invention is as follows:

A. styrene: purity is more than 99.9%, and dosage is 0.960-0.990.

B. Industrial white oil: the flash point is higher than 240 ℃, and the dosage of the colorless transparent liquid is 0.001-0.040.

C. Internal and external lubricants: paraffin, zinc stearate, calcium stearate, stearic acid amide and oleic acid amide, wherein the appearance of the lubricant is white particles or powder, the purity of the lubricant is more than 99.8 percent, and 2 or more than 2 additives in the lubricant are selected for compound use: the dosage is 0.001-0.005.

D. Antioxidant: BHT, Irganox1076, Irganox1010, Irganox 1330: one of the components is selected, and the dosage is 0.001-0.010.

E. Oil-soluble blue pigment (violet): the dosage is 10-50 ppm.

F. Ultraviolet absorbers and light stabilizers: tinuvin327, Tinuvin UVP, Tinuvin320, Tinuvin328, Tinuvin770 and Tinuvin622, and more than 2 ultraviolet absorbers and light stabilizers are compounded according to different product requirements and specification grades: the addition amount is 0.0001-0.005.

G. Organic peroxide initiator: tert-butyl peroxybenzoate; t-butyl peroxypivalate; 1. 1 di-tert-butylperoxy-3, 5 trimethylcyclohexane; 1. 1 di-tert-butylperoxy-cyclohexane; tert-butyl peroxynonanoate, compounded with 2 initiators according to different product requirements and specification grades: the addition amount is 0.0001-0.001.

H. Ethylbenzene: purity > 99.9%, and addition amount of 0.001-0.09.

The specific process is detailed as follows, and the used device is shown in the attached figure 2:

step one, styrene treatment:

the styrene is subjected to water removal and polymerization inhibitor removal through a styrene TBC removal tower filled with activated alumina, so that the styrene can be used for preparing polymer products with stable color and luster and good transparency.

Step two, styrene preheating and prepolymerization:

mixing a styrene raw material with polymerization inhibitor removed and a circulating liquid returned from a recovery device, preheating the mixture by a feeding preheater preset in front of a prepolymerization kettle, and then adding the mixture into the prepolymerization kettle, wherein the preheating process is only used for heating the monomers fed into the prepolymerization kettle to a reaction temperature or maintaining the constant feeding temperature during the normal reaction of the prepolymerization kettle, and a heating medium of the preheater is medium temperature oil or high temperature oil returned by a system so as to ensure the normal and stable performance of the prepolymerization reaction; in order to enable the prepolymerization reactor to reach the reaction temperature, the jacket of the prepolymerization reactor is heated by using low-temperature oil and high-temperature oil when the prepolymerization reactor is started, and the high-temperature oil is usually cut off after the reaction of the prepolymerization reactor is normal and the temperature of the jacket is maintained at a set value required by the process; a kettle top reflux condenser of the prepolymerization kettle cools styrene steam volatilized in the reaction kettle through cooling water, and the condensate liquid is refluxed into the prepolymerization kettle so as to achieve the purposes of removing reaction heat and controlling the temperature of the prepolymerization kettle; when the prepolymerization reactor is started, high-temperature oil is generally introduced into a jacket of a polymer pump and a jacket of a reaction material conveying pipeline, once the reaction is normal, the high-temperature oil is switched into medium-temperature oil, and the jacket of the reaction reactor maintains the state of automatic control of cold and hot oil feeding at a set temperature; the prepolymerization reactor is provided with a special type stirrer, and the stirrer is started when the process requirement is met, so that the normal stirring and mixing effects of the reaction reactor are maintained, and the heat transfer is enhanced; in the production process, a polymer pump continuously and stably feeds materials from a prepolymerization kettle to a postpolymerization reaction device and maintains the liquid level of the reaction kettle at a set value; in the normal production process, each feeding component is accurately metered according to the proportion requirement of the components in the formula and then is added into a prepolymerization kettle (the formula of each component comprises styrene feeding, recycled liquid feeding, white oil and other various additives and auxiliaries) so as to meet the requirement of producing a polystyrene product with specific performance.

Step three, post-polymerization reaction:

the material after the prepolymerization is continuously and stably fed from a prepolymerization reactor to a post-polymerization reaction device through a polymer pump, and the post-polymerization reaction device is two full mixed flow reaction reactors connected in series. The reaction material pumped from the polymer pump of the prepolymerization reactor firstly enters a first post-polymerization reactor of a post-polymerization reaction device, a jacket of the first post-polymerization reactor heats the reaction reactor by using low-temperature oil and high-temperature oil in order to enable the post-polymerization reactor to reach the reaction temperature when the reaction is started, and the first post-polymerization reactor cuts off the high-temperature oil after the reaction is normal and maintains the temperature of the jacket at a set value required by the process; the kettle top reflux condenser of the first post-polymerization kettle cools the styrene steam volatilized in the reaction kettle through cooling water, and returns the condensate to the pre-polymerization kettle to take away the reaction heat and achieve the purpose of controlling the temperature of the reaction kettle; when the first post-polymerization kettle is started, high-temperature oil is generally introduced into a jacket of the polymer pump and a jacket of the reactant conveying pipeline, once the reaction is normal, the high-temperature oil is switched into medium-temperature oil, and the jacket of the reaction kettle maintains the state of automatic control of cold and hot oil feeding at a set temperature; the first post-polymerization kettle is provided with a stirrer with a special type, and when the process requirement is met, the stirrer is started to maintain the normal stirring and mixing effect of the reaction kettle and enhance heat transfer; in the production process, a polymer pump of the first post-polymerization kettle continuously and stably feeds materials from the first post-polymerization kettle to the second post-polymerization kettle and maintains the liquid level of the reaction kettle at a set value.

The reaction material pumped from the polymer pump of the first post-polymerization kettle enters a second post-polymerization kettle of the post-polymerization reaction device, the jacket of the second post-polymerization kettle is heated by using low-temperature oil and high-temperature oil in order to enable the pre-polymerization kettle to reach the reaction temperature when the second post-polymerization kettle is started, and the second post-polymerization kettle normally cuts off the high-temperature oil after the reaction is normal and maintains the temperature of the jacket at the set value required by the process; the kettle top reflux condenser of the second postpolymerization kettle cools the styrene steam volatilized in the reaction kettle through cooling water and returns the condensate to the prepolymerization kettle to take away the reaction heat and achieve the purpose of controlling the temperature of the reaction kettle; when the second post-polymerizer is started, high-temperature oil is generally introduced into the jacket of the polymer pump jacket and the sleeve of the reactant conveying pipeline, once the reaction is normal, the medium-temperature/high-temperature hot oil in the sleeve of the material conveying pipe from the second post-polymerizer to the polymer devolatilization device is switched to the medium-temperature oil according to the actual situation, the high-temperature oil in the rest part of pipelines and the hot oil for equipment heat preservation is switched to the medium-temperature oil, and the jacket of the reaction kettle maintains the state of automatic control of cold and hot oil feeding at the set temperature; the second post-polymerization kettle is provided with a special type stirrer, and when the process requirement is met, the stirrer is started to maintain the normal stirring and mixing action of the reaction kettle and enhance heat transfer; in the production process, a polymer pump continuously and stably conveys materials from the second post-polymerization kettle to the devolatilization device and maintains the liquid level of the reaction kettle at the set liquid level.

Step four, preheating and devolatilizing the polymer:

the reactant is output from the second post-polymerization kettle by a polymer pump and is sent to a polymer devolatilization device through a pipeline. The pipeline from the polymer pump of the second post-polymerization kettle to the polymer devolatilization device adopts a jacketed pipe insulated by hot oil, and medium/high temperature hot oil is introduced into the jacketed pipe of the pipeline; the material sent into the polymer devolatilization device enters a polymer preheater for preheating, the polymer preheater adopts a single-tube pass tubular heat exchanger, hot oil is heated to go through a shell pass and the material goes through a tube pass, a mixing member for enhancing heat transfer is arranged in each tube for improving the heat transfer effect, two end sockets at two ends of the preheater are provided with jackets, and the jackets are filled with the hot oil so as to improve the heating effect; the polymer is heated to a sufficient temperature by high-temperature hot oil on the shell side in a tube array of a polymer preheater and then enters a first devolatilization kettle.

The outer wall of the cylinder body of the first devolatilization kettle is provided with a coil pipe heated and insulated by high-temperature hot oil, and the lower seal head is provided with a jacket heated and insulated by the hot oil. When the polymer enters the first devolatilization kettle from the preheater, the polymer is dispersed into fine strands by a polymer distributor arranged in the devolatilization kettle, so that volatile monomers and organic matters in the polymer can be removed more easily at high temperature and under high vacuum. The first devolatilization kettle is provided with two polymer pumps for conveying polymer melt to the second devolatilization kettle, and a jacket of the polymer pumps, a heating oil pipe and a hot oil heat-insulating jacket of a material conveying pipe from the first devolatilization kettle to the second devolatilization kettle are all filled with high-temperature hot oil for heat insulation and heating.

The outer wall of the cylinder of the second devolatilization kettle is provided with a coil pipe heated by high-temperature hot oil and used for heat preservation, and the lower seal head is provided with a jacket used for heating and heat preservation by hot oil. When the polymer is sent into the second devolatilization kettle from the first devolatilization kettle, two polymer pumps are used for feeding, and when the polymer is sent into the second devolatilization kettle, the polymer respectively enters two polymer distributors arranged in the devolatilization kettle through two inlets to disperse the polymer into fine strips, so that volatile monomers and organic matters in the polymer can be easily removed at high temperature and high vacuum. The second devolatilization kettle is provided with two polymer pumps for conveying polymer melt to two granulators of a downstream granulating device, and high-temperature hot oil for heat preservation and heating is introduced into a jacket and a heating oil pipe of the polymer pump, a hot oil heating jacket of a polymer filter, a die head extrusion template heating jacket and a hot oil heat preservation jacket of a material conveying pipe from the second devolatilization kettle to the granulating device.

The polymer devolatilization device is provided with two sets of independent hot oil circulating systems. One set is a circulation control system for independently supplying oil to the polymer preheater, and supplies oil to the shell pass of the preheater and controls the temperature; the other set is a circulation control system for supplying hot oil to equipment such as a jacket of a seal head of a polymer preheater, jackets and coil pipes of two devolatilization kettles, a polymer conveying pipeline sleeve, a polymer pump jacket, a polymer filter, a heating jacket of an extrusion die head of a downstream granulator and the like, and the hot oil with specific oil temperature is supplied to the equipment.

Step five, preparing the melt into finished pellets:

the granulating device is complete equipment provided by a professional granulator manufacturer, and is matched with polymers output by two polymer pumps of two devolatilization kettles butted with two granulators which are adaptive to the capacity of the polystyrene production line, so that melts are prepared into finished granules.

The transparent polystyrene obtained by adopting the process and the formula has good transparency, the tensile strength of the transparent polystyrene is 40-55MPa at normal temperature, and the transparent polystyrene is a thermoplastic material and mainly comprises the following componentsWherein n is the degree of polymerization, and the range of n is different from 600-7000, which is different according to the types of the products; besides the main components, the material also contains 0-7% of white oil, 0-1% of stearate additives and a small amount of organic residues (less than 800ppm in total) of monomers and the like, the molecular structure contains a small amount of macromolecules with special structures, and a certain amount of small hydrocarbon molecules are contained in gaps among the macromolecules, so that certain slippage can be generated among the macromolecules, and the material has good mechanical properties and optical properties compared with products obtained by other process production methods.

Based on the formula, the invention specifically selects the following formula:

A. styrene: purity is more than 99.9%, colorless transparent liquid, dosage is 0.96.

B. Industrial white oil: the flash point is more than 240 ℃, and the dosage is 0.03.

C. Internal and external lubricants: paraffin, zinc stearate, oleamide and the like, the appearance is white particles or powder, the purity is more than 99.8 percent, and the total compound dosage of the three is 0.005.

D. Antioxidant: irganox1076 in an amount of 0.001.

E. Oil-soluble blue pigment (violet): the dosage is 0.00005.

F. Ultraviolet absorbers and light stabilizers: tinuvin327 and Tinuvin UVP,2 items are used in a compound way, and the total addition amount is as follows: 0.0015.

G. organic peroxide initiator: tert-butyl peroxybenzoate; t-butyl peroxypivalate; the 2 items are used in combination, and the total addition amount is 0.005.

H. Ethylbenzene: purity > 99.9%, addition 0.05.

The preparation process of the above formulation is provided below:

step one, styrene treatment:

styrene from fresh supply passes through a styrene TBC removing tower filled with activated alumina, and water and TBC in the styrene are removed by an adsorption method, so that a raw material which can be used for preparing downstream polymers with good color stability is obtained.

Step two, prepolymerization:

continuously and stably adding the material components (styrene, white oil, stearate, polyfunctional group reactive auxiliary agent, diluent ethylbenzene, peroxide initiator and the like) in proportion into a prepolymerization kettle, and fully and powerfully stirring (the axial power is 3 kw/m)³) Under the condition of uniformly mixing, the temperature in the prepolymerization reactor is controlled at 130 ℃, the pressure is 380mmHg and the liquid level is stabilized for reaction, and the heat of reaction is removed through a reflux condenser at the top of the reactor. After 4 hours of reaction, the prepolymerization reaction is completed, and the raw materials are continuously and stably added into the first post-polymerization kettle of the next stage through a prepolymerization polymer delivery pump.

Step three, first post-polymerization reaction:

the material delivered from the prepolymerization pump of the prepolymerization kettle enters a first post-polymerization kettle, and the material entering the first post-polymerization kettle is stirred strongly (the axial power is 3 kw/m)³) Then, the reaction was carried out under the conditions of a pressure of 400mmHg at 150 ℃ and a stable liquid level, and the heat of reaction was removed by a reflux condenser at the top of the first postpolymerization vessel.After 4 hours of reaction, the first post-polymerization reaction is completed, and the raw materials are continuously and stably added into a second post-polymerization kettle of the next stage through a polymer delivery pump.

Step four, second post-polymerization reaction:

the material from the first postpolymerization tank is pumped into the second postpolymerization tank, and the material is stirred strongly (3 kw/m)³) Then, the reaction was carried out under the conditions of a pressure of 350mmHg at 150 ℃ and a stable liquid level. The reaction heat was removed from the first two stages of the reactor via a second postpolymerization kettle overhead reflux condenser. And finishing the second post-polymerization reaction after reacting for 4 hours, wherein the solid content in the reaction material reaches 77 percent, the viscosity reaches 300000cp, and the reaction material is continuously and stably output from the second post-polymerization kettle through a polymer delivery pump and enters a polymer preheater. In the material preheater, the material is heated from the reaction temperature of 150 ℃ to the demonomerization temperature of 220 ℃ by an internal member for strengthening heat transfer in a tube array under the heating of high-temperature crude oil, and then enters a first devolatilization kettle of the next stage for demonomerization.

Step five, first-stage high-temperature vacuum demonomerization:

the reactants from the polymer preheater enter a first devolatilization kettle, the material temperature of the materials is 220 ℃, the materials are subjected to high-temperature and low-pressure flash evaporation in the kettle under the pressure of 2.0kpa, more than 95% of unreacted styrene monomers, inert diluents and volatile organic matters are evaporated in the first devolatilization kettle, and the evaporated materials are pumped into a recovery system by a vacuum pump and are condensed and collected. At the moment, the material solvent is removed due to flash evaporation, the temperature of the material is reduced by 15 ℃, so that the viscosity of the material is increased to 1000000cp, and in order to ensure that the temperature of the material is not reduced too much and the viscosity is increased too much, the external part and the bottom end socket of the devolatilization kettle are heated by adopting high-temperature hot oil for heat preservation, the material of the polymer is maintained above 220 ℃, so that the material has certain fluidity and can achieve good volatile matter removal effect. After the primary high-temperature vacuum dehydration, the content of the residual volatile solvent of the obtained polymer material is reduced to about 1.25 percent, the temperature is 220 ℃, the viscosity is increased to 1000000cp., and the material is pumped to a second devolatilization kettle through a polymer pump for secondary high-temperature vacuum dehydration.

Step six, secondary high-temperature vacuum demonomerization:

the temperature of the polymer material from the first devolatilization kettle entering the second devolatilization kettle is 220 ℃, the pressure in the kettle is controlled below 1.5kPa, the material is subjected to high-temperature and low-pressure flash evaporation, the residual 95 percent of unreacted styrene monomer, inert diluent and volatile organic matters are further removed in the second-stage devolatilization kettle, and the unreacted styrene monomer, the inert diluent and the volatile organic matters are pumped into a recovery system by a vacuum pump and are condensed and collected. At the moment, the material solvent is removed due to secondary flash evaporation, the temperature of the material is reduced by 3 ℃, so that the viscosity of the material is increased to 2500000cp, in order to ensure that the viscosity of the material is increased too much, the outer part of the devolatilization kettle and the bottom end socket are heated by adopting high-temperature hot oil for heat preservation, the material of the polymer is maintained between 220 ℃, certain fluidity is kept, and a good volatile matter removing effect can be achieved. After secondary high-temperature vacuum demonomerization, the content of residual volatile solvent in the obtained polymer material is reduced to below 0.08%, the temperature is maintained at 230 ℃, and the viscosity is increased to 2500000cp.

And step seven, pumping the material to a granulator through a polymer pump for granulation to obtain a finished product.

The transparent polystyrene prepared by the process and the proportion has good transparency, and the tensile strength of the transparent polystyrene is 43Mpa at normal temperature.

The GPC test, the light transmittance and color test and the mechanical property test of the product in the formula range prove that the product obtained by the process and the formula has good mechanical, optical and application characteristics. The test results were as follows:

product thermal performance test meter

Load deformation temperature test table

Secondly, the mechanical property of the product is as follows:

thirdly, the optical performance of the product is as follows:

fourthly, the molecular weight distribution and the melt index of the product are as follows:

GPC results