阅读说明：本技术 羟基丙烯酸树脂水分散体的连续生产方法 (Continuous production method of hydroxy acrylic resin aqueous dispersion ) 是由 冯春源 焦晓东 肖淑焕 芦潇 葛源 李小龙 娄智兴 刘太恩 焦玉坤 于 2020-12-29 设计创作，主要内容包括：本发明提供一种羟基丙烯酸树脂水分散体的连续生产方法,该生产方法在连续生产装置中完成连续聚合、连续中和、连续分散的过程,操作简单、安全性高、提高了生产效率,所得的羟基丙烯酸树脂水分散体的固含量为40～50％,平均分散粒径小、分散均匀,粘度不高于1000cP,单体残留低、VOC含量低、对环境安全友好。(The invention provides a continuous production method of a hydroxyl acrylic resin aqueous dispersion, which finishes the processes of continuous polymerization, continuous neutralization and continuous dispersion in a continuous production device, is simple to operate and high in safety, improves the production efficiency, and the obtained hydroxyl acrylic resin aqueous dispersion has the solid content of 40-50%, small average dispersed particle size, uniform dispersion, viscosity of not higher than 1000cP, low monomer residue, low VOC content and is safe and friendly to the environment.)

1. A continuous production method of an aqueous dispersion of a hydroxyacrylic resin, characterized in that the continuous production method is carried out in a continuous production apparatus comprising a mixing system (1), a continuous conveying system (2), a polymerization reaction unit (3), a neutralization unit (4), a dispersion unit (5), a receiving system (6), and a heat exchange system,

wherein the outlet of the mixing system (1) is connected with the inlet of the continuous conveying system (2), the outlet of the continuous conveying system (2) is connected with the inlet of the polymerization reaction unit (3), the outlet of the polymerization reaction unit (3) is connected with the inlet of the neutralization unit (4), the outlet of the neutralization unit (4) is connected with the inlet of the dispersion unit (5), the outlet of the dispersion unit (5) is connected with the inlet of the receiving system (6),

the solid content of the hydroxyl acrylic resin aqueous dispersion is 40-50%, and the viscosity is not higher than 1000 cP.

2. The continuous production method according to claim 1, wherein the mixing system (1) comprises at least a first mixer (1-1), a second mixer (1-2), and a third mixer (1-3), and the first mixer (1-1), the second mixer (1-2), and the third mixer (1-3) are used for mixing the first material-mixed liquid, the second material-mixed liquid, and the third material-mixed liquid, respectively;

the first material mixed liquor contains a monomer, the second material mixed liquor contains a solvent and an initiator, and the third material mixed liquor contains a monomer, a solvent and an initiator.

3. The continuous production method according to claim 1 or 2, wherein the heat exchange system comprises a material mixed liquor first-stage preheating system/dispersion cooling system (8), a material mixed liquor second-stage preheating system/resin cooling system (7), and a reaction temperature control system (9), wherein the material mixed liquor first-stage preheating and the dispersion cooling are performed by using the same heat exchange medium, and the material mixed liquor second-stage preheating and the resin cooling are performed simultaneously.

4. The continuous production process according to claim 1 or 2, wherein the polymerization reaction unit (3) is a continuous channel reactor in any combination of a microchannel reactor and a static tubular reactor, the microchannel reactor comprising at least one micro-reaction sheet;

the neutralization unit (4) comprises a neutralization reagent inlet, a resin inlet and a neutralized resin outlet; the dispersion unit (5) comprises a deionized water inlet, a neutralized resin inlet and a dispersion outlet.

5. The continuous production method according to claim 1 or 2, wherein the receiving system (6) comprises a receiver and a storage tank, the outlet of the dispersion unit (5) being connected to the inlet of the receiver and the outlet of the receiver being connected to the inlet of the storage tank.

6. The continuous production process according to claim 2, comprising the steps of:

step 1: preparing a first material mixed solution, a second material mixed solution and a third material mixed solution by using a monomer, a solvent and an initiator, and respectively entering a first mixer (1-1), a second mixer (1-2) and a third mixer (1-3) for mixing; the mass ratio of the monomer to the solvent to the initiator is 80-90: 10-20: 2-4;

step 2: continuously conveying the first material mixed solution and the second material mixed solution to the polymerization reaction unit (3) through the continuous conveying system (2), reacting at the temperature of 170-210 ℃, and continuously reacting with the third material mixed solution continuously conveyed to the polymerization reaction unit (3) through the continuous conveying system (2) at the temperature of 170-210 ℃ to obtain the hydroxy acrylic resin, wherein the total residence time of the first material mixed solution, the second material mixed solution and the third material mixed solution in the polymerization reaction unit (3) is 3-20 min;

and step 3: cooling the obtained hydroxyl acrylic resin to 100-130 ℃ by the material mixed liquid secondary preheating system/resin cooling system (7), then feeding the hydroxyl acrylic resin into the neutralization unit (4), and reacting the hydroxyl acrylic resin with a neutralization reagent continuously conveyed into the neutralization unit (4) for 10-100 seconds to obtain neutralized resin;

and 4, step 4: enabling the neutralized resin to continuously enter the dispersing unit (5), and mixing and dispersing the neutralized resin with deionized water continuously conveyed into the dispersing unit (5) for 30-120 seconds to obtain a hydroxy acrylic resin aqueous dispersion; the proportion of the deionized water in the hydroxyl acrylic resin water dispersion is 40-56%;

and 5: and enabling the hydroxyl acrylic resin aqueous dispersion to enter the receiving system (6), and enabling the hydroxyl acrylic resin aqueous dispersion to enter a storage tank after being cooled to 25-35 ℃ by the material mixed liquid primary preheating system/dispersion cooling system (8).

7. The continuous production method according to claim 6, wherein the first material mixture is preheated to 40 to 50 ℃ in the first mixer (1-1) by the material mixture first-stage preheating system/dispersion cooling system (8), the first material mixture is continuously conveyed to the polymerization reaction unit (3) by the continuous conveying system (2) and the material mixture second-stage preheating system/resin cooling system (7), and the first material mixture is preheated to 100 to 130 ℃ by the material mixture second-stage preheating system/resin cooling system (7).

8. The continuous production method according to claim 6, wherein the monomers in step 1 comprise 12-39% of hydroxyl monomers, 1.3-3% of carboxyl monomers, 10-80% of (meth) acrylate monomers and 5-50% of styrene based on the total monomer mass.

9. The continuous production method according to claim 8, wherein the hydroxyl monomer is one or more of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, and hydroxybutyl methacrylate; the carboxyl monomer is at least one of acrylic acid and methacrylic acid; the (methyl) acrylate monomer is one or more of methyl (methyl) acrylate, ethyl (methyl) acrylate, isooctyl (methyl) acrylate, butyl (methyl) acrylate and isobornyl (methyl) acrylate.

10. The continuous production method according to claim 6, wherein the solvent in step 1 is one or more selected from propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol butyl ether, propylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, toluene, xylene, No. 100 mineral spirits, butyl acetate, isobutyl acetate, n-butanol, and isobutanol; the initiator in the step 1 is one or more of di-tert-butyl peroxide, di-tert-amyl peroxide, diisopropyl peroxide, di-tert-butyl dicumyl peroxide and tert-butyl cumyl peroxide;

the neutralizing agent in the step 3 is one or more of N, N-dimethylethanolamine, N-methylmonoethanolamine, N-methyldiethanolamine, ethanolamine, diethanolamine and triethanolamine, and the neutralization degree of the hydroxyl acrylic resin is 70-90%.

Technical Field

The invention relates to a continuous production method of a hydroxy acrylic resin aqueous dispersion, in particular to a continuous production method of a low-viscosity hydroxy acrylic resin aqueous dispersion.

Background

The traditional solvent type polyurethane coating is widely applied in various fields due to various excellent performances, but the traditional solvent type polyurethane coating contains more organic solvents, is harmful to the environment and human health, and along with the increasing importance of people on environment protection, the application of the solvent type coating is also more and more limited, and the water-based coating belongs to the environment-friendly coating due to the fact that the main solvent is water, and has become the development trend of the coating industry. The hydroxyl acrylic resin aqueous dispersion is widely applied to the coating industry, and the two-component waterborne polyurethane prepared by reacting with an isocyanate curing agent has good weather resistance, glossiness, fullness and film forming property, can be used as a finishing coat, a varnish, an industrial baking paint, an anticorrosive coating and the like for the fields of woodware, automobiles, engineering machinery, rail transit, metal corrosion prevention, building internal and external walls, plastics, glass and the like, and has more relevant reports on the synthesis research of the hydroxyl acrylic resin aqueous dispersion in order to meet the application requirements of different fields.

Chinese patent publication No. CN101914185B discloses a method for producing an aqueous dispersion of a hydroxy acrylic resin, which discloses a method of stepwise polymerization and increasing the polymerization temperature to make the half-life of the initiator within several minutes. Although the rapid decomposition of the initiator at a higher temperature will increase the concentration of the free radicals and thus reduce the molecular weight and viscosity of the polymer, as is common knowledge of those skilled in the art, the batch preparation method has a great amplification effect during industrial scale-up, and not only has a high potential safety hazard during industrial production, but also increases the running cost and reduces the production efficiency. The reason is that in the industrial production, the production capacity of a batch of batch reactors is large, the material is in the range of several tons to dozens of tons, when the polymerization temperature is raised, the half-life period of the initiator is greatly shortened, the number of free radicals is rapidly increased in a short time, the polymerization reaction is rapidly carried out at a high temperature, and simultaneously a large amount of heat is released, if the dripping speed is high, the reaction is easy to lose control, a great safety risk exists, and in order to ensure the safety and controllability of the reaction, the heat is timely removed, the dripping speed can only be slowed down, and the flow of the heat exchange medium is increased. The components in the batch reactor become more and more complex along with the reaction, the components comprise unreacted monomers and polymers polymerized to different degrees, the mixed solution of the monomers and the initiator is continuously dripped, the monomers and the polymers are continuously polymerized while the monomers are polymerized, the molecular weight of the polymers is increased and uneven, and the larger the treatment amount is, the longer the dripping time is, the wider the molecular weight distribution of the obtained polymerization product is, and the larger the viscosity is.

Chinese patent publication No. CN111167395A discloses a system and method for continuously producing an aqueous dispersion of hydroxy acrylic resin, wherein a plurality of prepolymerization reactors connected in parallel are used to complete the polymerization of monomers, a high-speed mixer is used to achieve neutralization and preliminary dispersion, and a dispersion reactor and a static mixer are used to complete multiple dispersions, so that continuous production can be achieved as a whole.

According to the common knowledge of the skilled person, when the hydroxy acrylic resin is dispersed by adding water, a phase inversion process exists, the state of the dispersion is changed from water-in-oil to oil-in-water with the increase of the water amount, the viscosity of the dispersion is changed during the phase inversion process, and the process of firstly reducing, then increasing and then reducing is carried out, and a viscosity peak exists during the phase inversion process. Due to the viscosity change during the dispersion, the dispersion apparatus is required to be high and the conditions for the dispersion process are severe enough to provide a sufficiently strong shearing force, and the resulting aqueous dispersion of the hydroxyacrylic resin has a large and uneven particle size and poor stability. In order to improve dispersibility and reduce viscosity of the aqueous dispersion, there are generally used methods of: the use of chain transfer agents in the synthesis of resins has led to a reduction in the molecular weight of polymers, as described in chinese patents CN102161770B, CN103772597B, CN107163177B, CN 108530578A; the viscosity of the resin is reduced by using more solvent, such as CN 102161770B; increasing the amount of acidic monomer to increase the acid value of the resin allows the resin to generate more hydrophilic groups during the neutralization stage, such as chinese patent CN 101457005B; dispersing agents or emulsifiers such as vinyl sulfonate, which can participate in polymerization reaction, are added in the synthesis process of the resin to increase the hydrophilicity of the resin, such as Chinese patent CN 108530578A; reactive solvents such as glycidyl versatate, monoglycidyl ether, etc. are added to reduce the viscosity of the resin, as in chinese patents CN104356291A, CN106008790A, CN 108530578A. However, the chain transfer agents used in the resin synthesis process mostly have an irritating odor, which causes the final aqueous dispersion to have an irritating odor and also increases the cost; the more solvents can cause the VOC to be too high or increase the post-treatment process of the desolventizing, for example, Chinese patents CN102161770B, CN11107284A, CN111285957A, CN101649098B, CN109608575B and CN111040067A select to evaporate part or all of the organic solvent after the polymerization reaction and before the neutralization and dispersion, but when most of the solvent is evaporated, the viscosity of the resin is greatly improved, the difficulty of dispersion is increased, the neutralization and dispersion are not uniform, and the gelation phenomenon is easy to occur in the process of evaporating the solvent; the acid value of the resin is increased by increasing the using amount of the acidic monomer, so that the water resistance and alkali resistance of the resin are reduced, the water resistance of the resin is also reduced by adding the dispersing agent or the emulsifying agent, the water resistance of the prepared polyurethane coating is poor due to increasing the using amount of the acidic monomer and adding the dispersing agent or the emulsifying agent, and the application range is reduced; although the addition of the reactive solvent can reduce the viscosity of VOC and resin to a certain extent, the addition of the reactive solvent can also affect the performance of downstream coatings, so that a paint film becomes soft and the corrosion resistance is reduced. In the existing production technology, a kettle type process is mostly adopted in a polymerization stage, and an intermittent mode is mostly adopted in a dispersion stage, so that the aqueous dispersion with the solid content of 40-50%, the viscosity of less than 1000cp and the average particle size of about 100nm is difficult to obtain under the conditions that the dosage of a solvent is small, the dosage of an acidic monomer is small, and a chain transfer agent, a dispersing agent or an emulsifying agent, a reactive solvent (an active diluent) or additives are not added or are all very small in the resin synthesis process.

In order to solve the above problems, in the technical scheme disclosed in chinese patent publication No. CN111167395A, a high-speed mixer, a dispersion kettle and a static mixer are sequentially used to perform dispersion for multiple times, so as to overcome the problems of difficult dispersion and low single kettle yield caused by high viscosity point during phase transition, but the dispersion process is complicated, and the dispersion process still has a state of changing from oil-rich water to oil-poor water due to multiple additions of moisture, especially in the dispersion stage of the dispersion kettle, the process of transferring the dispersion after high-speed dispersion for a period of time from the bottom of the dispersion kettle to the second static mixer may have uneven discharge due to large cross-sectional area of the dispersion kettle and obvious back-mixing phenomenon, resulting in uneven dispersion. Chinese patent publication No. CN109608575A discloses a hydroxyl-containing polyacrylate secondary aqueous dispersion and a preparation method thereof, wherein a dispersion process of slowly dropping a copolymer into water is adopted in the disclosed technical scheme, and compared with a dispersion process of diluting resin with water, the dispersion system is always in an oil-in-water state, has no phase inversion and is easy to disperse, but the resin needs to be heated to a higher temperature in advance in the process of dropping the resin into a dilution tank and needs to be kept warm in the process of dropping, and the energy consumption is significantly increased in the operation process.

Disclosure of Invention

Problems to be solved by the invention

The invention provides a continuous production method of hydroxyl acrylic resin aqueous dispersion, and aims to solve the problems of high dispersion viscosity, large and uneven dispersion particle size, complex operation in a production process and poor safety in the prior production technology.

Means for solving the problems

[1] A continuous production method of an aqueous dispersion of a hydroxyacrylic resin, wherein the continuous production method is carried out in a continuous production apparatus comprising a mixing system 1, a continuous conveying system 2, a polymerization reaction unit 3, a neutralization unit 4, a dispersion unit 5, a receiving system 6, and a heat exchange system,

wherein the outlet of the mixing system 1 is connected with the inlet of the continuous conveying system 2, the outlet of the continuous conveying system 2 is connected with the inlet of the polymerization reaction unit 3, the outlet of the polymerization reaction unit 3 is connected with the inlet of the neutralization unit 4, the outlet of the neutralization unit 4 is connected with the inlet of the dispersion unit 5, the outlet of the dispersion unit 5 is connected with the inlet of the receiving system 6,

the solid content of the hydroxyl acrylic resin aqueous dispersion is 40-50%, and the viscosity is not higher than 1000 cP.

[2] The continuous production method according to [1], wherein the mixing system 1 comprises at least a first mixer 1-1, a second mixer 1-2, and a third mixer 1-3, and the first mixer 1-1, the second mixer 1-2, and the third mixer 1-3 are used for mixing the first material mixed solution, the second material mixed solution, and the third material mixed solution, respectively;

the first material mixed liquor contains a monomer, the second material mixed liquor contains a solvent and an initiator, and the third material mixed liquor contains a monomer, a solvent and an initiator.

[3] The continuous production method according to [1] or [2], wherein the heat exchange system comprises a material mixed liquid first-stage preheating system/dispersion cooling system 8, a material mixed liquid second-stage preheating system/resin cooling system 7, and a reaction temperature control system 9, wherein the material mixed liquid first-stage preheating and the dispersion cooling are performed by using the same heat exchange medium, and the material mixed liquid second-stage preheating and the resin cooling are performed simultaneously.

[4] The continuous production process according to [1] or [2], wherein the polymerization reaction unit 3 is a continuous channel reactor in which a microchannel reactor comprising at least one piece of a micro reaction sheet is arbitrarily combined with a static tubular reactor;

the neutralization unit 4 comprises a neutralization reagent inlet, a resin inlet and a neutralized resin outlet; the dispersion unit 5 comprises a deionized water inlet, a neutralized resin inlet and a dispersion outlet.

[5] The continuous production method according to [1] or [2], wherein the receiving system 6 comprises a receiver and a storage tank, an outlet of the dispersing unit 5 is connected with an inlet of the receiver, and an outlet of the receiver is connected with an inlet of the storage tank.

[6] The continuous production method according to [2], which comprises the steps of:

step 1: preparing a first material mixed solution, a second material mixed solution and a third material mixed solution by using a monomer, a solvent and an initiator, and respectively entering a first mixer 1-1, a second mixer 1-2 and a third mixer 1-3 for mixing; the mass ratio of the monomer to the solvent to the initiator is 80-90: 10-20: 2-4;

step 2: continuously conveying the first material mixed solution and the second material mixed solution to the polymerization reaction unit 3 through the continuous conveying system 2, reacting at the temperature of 170-210 ℃, and continuously reacting with the third material mixed solution continuously conveyed to the polymerization reaction unit 3 through the continuous conveying system 2 at the temperature of 170-210 ℃ to obtain the hydroxy acrylic resin, wherein the total residence time of the first material mixed solution, the second material mixed solution and the third material mixed solution in the polymerization reaction unit 3 is 3-20 min;

and step 3: cooling the obtained hydroxyl acrylic resin to 100-130 ℃ through the material mixed liquid secondary preheating system/resin cooling system 7, then feeding the hydroxyl acrylic resin into the neutralization unit 4, and reacting the hydroxyl acrylic resin with a neutralization reagent continuously conveyed into the neutralization unit 4 for 10-100 seconds to obtain neutralized resin;

and 4, step 4: enabling the neutralized resin to continuously enter the dispersing unit 5, and mixing and dispersing the neutralized resin and deionized water continuously conveyed into the dispersing unit 5 for 30-120 seconds to obtain a hydroxyl acrylic resin aqueous dispersion; the proportion of the deionized water in the hydroxyl acrylic resin water dispersion is 40-56%;

and 5: and enabling the hydroxyl acrylic resin aqueous dispersion to enter the receiving system 6, and enabling the hydroxyl acrylic resin aqueous dispersion to enter a storage tank after being cooled to 25-35 ℃ by the material mixed liquid primary preheating system/dispersion cooling system 8.

[7] The continuous production method according to [6], wherein the first material mixed solution is preheated to 40-50 ℃ in the first mixer 1-1 through the material mixed solution first-stage preheating system/dispersion cooling system 8, the first material mixed solution is continuously conveyed to the polymerization reaction unit 3 through the continuous conveying system 2 and the material mixed solution second-stage preheating system/resin cooling system 7, and the first material mixed solution is preheated to 100-130 ℃ through the material mixed solution second-stage preheating system/resin cooling system 7.

[8] The continuous production method according to [6], wherein the monomers in the step 1 comprise a hydroxyl monomer, a carboxyl monomer and optionally a (meth) acrylate monomer and styrene, wherein the hydroxyl monomer accounts for 12-39%, the carboxyl monomer accounts for 1.3-3%, the (meth) acrylate monomer accounts for 10-80%, and the styrene accounts for 5-50% of the total monomer mass.

[9] The continuous production method according to [8], wherein the hydroxyl monomer is one or more of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate and hydroxybutyl methacrylate; the carboxyl monomer is at least one of acrylic acid and methacrylic acid; the (methyl) acrylate monomer is one or more of methyl (methyl) acrylate, ethyl (methyl) acrylate, isooctyl (methyl) acrylate, butyl (methyl) acrylate and isobornyl (methyl) acrylate.

[10] The continuous production process according to [6], wherein the solvent in the step 1 is one or more selected from propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol butyl ether, propylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, toluene, xylene, No. 100 mineral spirits, butyl acetate, isobutyl acetate, n-butanol and isobutanol; the initiator in the step 1 is one or more of di-tert-butyl peroxide, di-tert-amyl peroxide, diisopropyl peroxide, di-tert-butyl dicumyl peroxide and tert-butyl cumyl peroxide;

the neutralizing agent in the step 3 is one or more of N, N-dimethylethanolamine, N-methylmonoethanolamine, N-methyldiethanolamine, ethanolamine, diethanolamine and triethanolamine, and the neutralization degree of the hydroxyl acrylic resin is 70-90%.

ADVANTAGEOUS EFFECTS OF INVENTION

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

1. the viscosity of the hydroxyl acrylic resin aqueous dispersion produced by the continuous production method is obviously reduced, the monomer and the initiator in the continuous production method of the hydroxyl acrylic resin aqueous dispersion are quickly mixed in a microchannel reactor of a continuous channel reactor, the phenomenon of local excess or deficiency of the initiator does not exist, the initiator is quickly decomposed to generate free radicals in a short time by adopting a high-temperature high-pressure mode, the polymerization reaction is quickly initiated, the time required by chain initiation is shortened, the length of a molecular chain is uniformly and quickly shortened to a certain extent in a reaction channel of plug flow in the whole chain growth process, the occurrence of branching is reduced, the finally obtained hydroxyl acrylic resin has smaller molecular weight, concentrated distribution and small viscosity, the resistance in the resin dispersion process is reduced to a certain extent, and the resistance in the resin dispersion process is further reduced by adopting a continuous dispersion mode at a higher temperature in a dispersion stage The dispersing process is easier to carry out, the average particle size of the dispersion obtained after forced shearing and dispersing is about 100nm, the dispersion is uniform, the viscosity can be reduced to below 1000cP when the solid content is 40-50%, and the hydrophilicity of the resin is not required to be improved by increasing the using amount of the carboxyl monomer, so that the acid value is reduced to a certain extent, the using amount of a neutralizing reagent is reduced, and the quality and downstream application performance of the hydroxyl acrylic resin aqueous dispersion are ensured.

2. The continuous production method of the hydroxyl acrylic resin water dispersion provided by the invention realizes continuous production, the whole production process can be automatically controlled, the operation is simple, the safety is high, energy is used mechanically in the production process, the energy consumption is reduced, the conversion rate of monomers is improved by adopting a high-temperature high-pressure sectional feeding and continuous reaction mode in a polymerization reaction stage, the monomer residue is not higher than 0.5%, the solvent consumption is low, the VOC content is not higher than 10%, and the method is safe and friendly to the environment.

Drawings

FIG. 1 is a schematic view of a continuous production process of an aqueous dispersion of a hydroxyacrylic resin according to the present invention.

Description of the reference numerals

1. The system comprises a material mixing system, 1-1, a first material mixer, 1-2, a second material mixer, 1-3, a third material mixer, 2, a continuous conveying system, 3, a polymerization reaction unit, 4, a neutralization unit, 5, a dispersion unit, 6, a receiving system, 7, a material mixed solution second-stage preheating system/resin cooling system, 8, a material mixed solution first-stage preheating system/dispersion cooling system, 9, a reaction temperature control system

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the drawings described herein are not to be construed as limiting the scope of the invention.

The invention provides a continuous production method of hydroxyl acrylic resin aqueous dispersion, which is carried out in a continuous production device, wherein the continuous production device comprises a mixing system 1, a continuous conveying system 2, a polymerization reaction unit 3, a neutralization unit 4, a dispersing unit 5, a receiving system 6 and a heat exchange system, wherein an outlet of the mixing system 1 is connected with an inlet of the continuous conveying system 2, an outlet of the continuous conveying system 2 is connected with an inlet of the polymerization reaction unit 3, an outlet of the polymerization reaction unit 3 is connected with an inlet of the neutralization unit 4, an outlet of the neutralization unit 4 is connected with an inlet of the dispersing unit 5, and an outlet of the dispersing unit 5 is connected with an inlet of the receiving system 6.

In the invention, each system and unit in the continuous production device for producing the hydroxyl acrylic resin aqueous dispersion are connected with an automatic control system, and the continuous automatic production of the hydroxyl acrylic resin aqueous dispersion can be realized by adopting automatic operation.

In the present invention, it should be noted that, unless explicitly stated or limited, the connection between each system and the unit should be understood in a broad sense, for example, it may be a direct pipe connection, a pipe connection connected with a pipe valve, an indirect connection through an intermediate medium, a fixed connection, or a detachable connection. The specific meaning of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the invention, the solid content of the hydroxyl acrylic resin aqueous dispersion is 40-50%, and the viscosity is not higher than 1000 cP.

In one embodiment of the present invention, the mixing system 1 at least comprises a first mixer 1-1, a second mixer 1-2, and a third mixer 1-3, wherein the first mixer 1-1, the second mixer 1-2, and the third mixer 1-3 are respectively used for mixing a first material mixed solution, a second material mixed solution, and a third material mixed solution; preferably, the first mixer 1-1 is a stirred tank with jacket heat exchange, and the second mixer 1-2 and the third mixer 1-3 are stirred tanks.

The first material mixed liquor contains a monomer, the second material mixed liquor contains a solvent and an initiator, and the third material mixed liquor contains a monomer, a solvent and an initiator.

In the invention, the heat exchange system comprises a material mixed liquid primary preheating system/dispersion cooling system 8, a material mixed liquid secondary preheating system/resin cooling system 7 and a reaction temperature control system 9, wherein the material mixed liquid primary preheating and the dispersion cooling are carried out by using the same heat exchange medium, and the material mixed liquid secondary preheating and the resin cooling are carried out simultaneously.

In the invention, the mixer is used for realizing the early-stage mixing of materials, and the early-stage mixing aims to realize that the materials which do not react with each other and can be mixed in advance are formed into a strand of material and then conveyed to the polymerization reaction unit 3 through the continuous conveying system 2, thereby achieving the aim of saving the input cost of equipment. The first material mixer 1-1 is used for mixing monomers, the second material mixer 1-2 is used for mixing a solvent and an initiator, and the third material mixer 1-3 is used for mixing the monomers, the solvent and the initiator. The reason why the first mixer 1-1 adopts the stirring kettle with the jacket for heat exchange is to preheat the first material mixed liquid.

In the present invention, the continuous conveying system 2 is used for realizing the continuous conveying of the materials and providing power for the flowing of the materials in the continuous production device. Because the polymerization reaction unit 3, the neutralization unit 4 and the dispersion unit 5 in the continuous production device are all static devices, the only power source is the continuous conveying system 2, and because the three units are of mixed structures, the materials generate certain resistance in the flowing process, and therefore certain pressure drop is generated; in addition, because the temperature in the reaction process is higher than the boiling point of the solvent and part of the monomers, a certain pressure needs to be provided in order to prevent the materials from vaporizing. Therefore, in order to realize that the material can enter the polymerization reaction unit 3 and smoothly pass through the neutralization unit 4 and the dispersion unit 5 to the receiving system 6, the continuous conveying system 2 preferably comprises at least four feed pumps having a pressure-resistant range, and the upper pressure-resistant limit of the feed pumps is not lower than 1.5 MPa. If the upper limit of the pressure resistance of the feed pump is lower than 1.5MPa, the power provided in the process of conveying the materials is limited, which can cause that the products can not smoothly enter the receiving system 6, or the feeding is stopped because the pressure of the whole continuous production device is higher than the upper limit of the pressure of the feed pump.

In the present invention, the polymerization reaction unit 3 is a continuous channel reactor. Preferably, the continuous channel reactor adopts a continuous channel reactor with any combination of a microchannel reactor and a static tubular reactor, and the microchannel reactor at least comprises one piece of micro reaction sheet; more preferably, the inlet of the polymerization unit 3 is arranged on the microchannel reactor and the outlet of the polymerization unit 3 is arranged on the static tubular reactor. The continuous channel reactor can be connected in a mode of a first group of microchannel reactors and a first static tubular reactor, and is sequentially combined with a second group of microchannel reactors and a second static tubular reactor in series.

The conventional batch kettle type reaction mostly adopts the method that a solvent is added into a reaction kettle in advance and preheated to a certain temperature, and then the monomer and the initiator are dripped for many times, and in order to ensure the controllable reaction and the product quality, a starvation method for reducing the dripping speed is adopted, so that the initiator with higher concentration is always kept in the monomer. However, in order to realize mass production, the reaction kettle adopted in industrial production generally has a large volume, and although the stirring form is continuously improved, the phenomena of uneven mixing and serious back mixing always exist in the reaction kettle, so that the polymerization degree of the resin, the difference of the resin structure and the molecular weight distribution are large, the molecular weight distribution is wide, and the viscosity of the resin is large, the later-stage dispersion is difficult, and the product quality is low and unstable.

According to the invention, for the synthesis of the hydroxyl acrylic resin, a large number of experimental researches show that whether the polymerization monomer and the initiator are fed separately or fed after being premixed, a forced mass transfer process is required in the early stage of the reaction, so that the free radicals generated by the rapid decomposition of the initiator at high temperature can be uniformly contacted with the monomer, the polymerization monomer is uniformly subjected to polymerization reaction in the process of flowing in a reaction channel, a molecular chain with more concentrated molecular weight is formed, the branching degree is reduced, and the molecular chain with higher polymerization degree is avoided. Therefore, the invention adopts the microchannel reactor as the front end of the continuous channel reactor, and the inlet of the polymerization reaction unit 3 is arranged on the microchannel reactor of the continuous channel reactor, thereby achieving the effect of rapid and uniform mixing and reaction under higher temperature, pressure and flow rate. Because the channel of the micro-reaction plate in the micro-channel reactor is thin and has a complex structure, mass production is difficult to realize, but the micro-reaction plate is combined with the static tubular reactor, and under the premise that free radicals generated by decomposition of the initiator and polymerization monomers are uniformly mixed and partially react, polymerization reaction liquid can rapidly flow in the tubular channel of plug flow after entering the static tubular reactor to keep uniform reaction. Thus, in one embodiment of the present invention, the outlet of the polymerization unit 3 is arranged on a static tubular reactor.

In the invention, the material of the micro-reaction sheet in the micro-channel reactor is made of an economic stainless steel material with good pressure-resistant effect, so that the rapid mixing can be realized, the static tubular reactor is a wound tube reactor or a tubular reactor, and the micro-channel reactor and the static tubular reactor can be commercially obtained on the market and are assembled according to the capacity requirement. In one embodiment of the invention, the characteristic dimension of the micro reaction plate in the micro-channel reactor is 3-8 mm, the effective liquid holding capacity of one micro reaction plate is 0.2-1L, the pipeline dimension of the static tubular reactor is 5-15 mm, and the effective liquid holding capacity is 1-200L.

In the present invention, the neutralization unit 4 includes a neutralization agent inlet, a resin inlet, and a neutralized resin outlet; the dispersion unit 5 comprises a deionized water inlet, a neutralized resin inlet and a dispersion outlet. Preferably, the neutralization unit 4 and the dispersion unit 5 both use a tube bundle reactor having a strong mixing function. The tube bundle type reactor is a commercially available or customized reactor with a static mixing structure in a reaction cavity, and can be selected according to the requirement of capacity. In one embodiment of the invention, the tube bundle reactor is made of an economical stainless steel material with good pressure resistance effect, and the reaction cavity is provided with a detachable insert mixing structure, so that the effective liquid holdup is 1-50L.

In the invention, the receiving system 6 comprises a receiver and a storage tank, the outlet of the dispersing unit 5 is connected with the inlet of the receiver, the outlet of the receiver is connected with the inlet of the storage tank, and preferably, the receiver is a pipe mixer with jacket heat exchange. The heat exchange medium of the first mixer 1-1 is the same as that of the receiver, and the heat exchange medium and the receiver are communicated by adopting a circulating pump serving as a material mixed solution first-stage preheating system/dispersion cooling system 8.

In the invention, the monomer polymerization needs to be carried out at a certain temperature, the polymerization process is an exothermic process, the polymerization reaction rate is higher at a higher reaction temperature, and more heat is released in the reaction, so that the reaction temperature is provided by the reaction temperature control system 9, and the reaction heat is removed in time. In addition, since the reaction temperature of the polymerization reaction unit 3 is high, the temperature of the hydroxy acrylic resin flowing out through the polymerization reaction unit 3 is high, and neutralization and dispersion cannot be directly performed, otherwise, the quality of the product is affected, and therefore, temperature reduction treatment is required. In addition, the equipment adopted for neutralization and dispersion after the temperature of the resin is reduced does not have the heat exchange function, so that the temperature of the finally obtained dispersion is higher than the normal temperature. In order to facilitate the storage of the dispersoid, the temperature of the dispersoid needs to be reduced to the temperature required by the storage, and in order to realize the full utilization of energy, the temperature reduction of the resin and the temperature reduction of the dispersoid are combined with the preheating of the monomer and are simultaneously realized.

In the invention, the heat exchange jacket of the receiver and the heat exchange jacket of the first mixer 1-1 are communicated through the circulating pump, the heat exchange medium flowing out of the receiver is pumped to the inlet of the heat exchange jacket of the first mixer 1-1 through the circulating pump and then returns to the inlet of the heat exchange medium of the receiver from the outlet of the heat exchange jacket of the first mixer, thereby forming a circulation, and realizing the first-stage preheating of the first material mixed solution and the cooling of the resin dispersoid through the heating and cooling processes of the heat exchange medium. Preferably, the heat exchange medium is water or silicone oil. The second-stage preheating of the first material mixed liquid and the cooling of the resin by the resin cooling system are preferably completed in the same heat exchange device (for example, the material mixed liquid second-stage preheating system/resin cooling system 7), so that the rapid cooling of the resin and the rapid heating of the material mixed liquid are realized. The heat exchange equipment is preferably a tubular heat exchanger.

In the invention, the materials for producing the hydroxyl acrylic resin aqueous dispersion are all industrial grade materials which are all commercially available; the various components of the continuous production apparatus employed, such as the piping, valves, controllers, feed pumps, microchannel reactors, static tubular reactors, receivers, etc., are commercially available or custom-made, but the entire continuous production apparatus is not commercially available or known to those skilled in the art.

In one embodiment of the present invention, as shown in fig. 1, the continuous production method of the aqueous dispersion of a hydroxyacrylic resin comprises the steps of:

step 1: preparing a first material mixed solution, a second material mixed solution and a third material mixed solution by using a monomer, a solvent and an initiator, and respectively entering a first mixer 1-1, a second mixer 1-2 and a third mixer 1-3 for mixing; the mass ratio of the monomer to the solvent to the initiator is 80-90: 10-20: 2-4;

step 2: continuously conveying the first material mixed solution and the second material mixed solution to the polymerization reaction unit 3 through the continuous conveying system 2, reacting at the temperature of 170-210 ℃, and continuously reacting with the third material mixed solution continuously conveyed to the polymerization reaction unit 3 through the continuous conveying system 2 at the temperature of 170-210 ℃ to obtain the hydroxy acrylic resin, wherein the total residence time of the first material mixed solution, the second material mixed solution and the third material mixed solution in the polymerization reaction unit 3 is 3-20 min;

and step 3: cooling the obtained hydroxyl acrylic resin to 100-130 ℃ through the material mixed liquid secondary preheating system/resin cooling system 7, then feeding the hydroxyl acrylic resin into the neutralization unit 4, and reacting the hydroxyl acrylic resin with a neutralization reagent continuously conveyed into the neutralization unit 4 for 10-100 seconds to obtain neutralized resin;

and 4, step 4: enabling the neutralized resin to continuously enter the dispersing unit 5, and mixing and dispersing the neutralized resin and deionized water continuously conveyed into the dispersing unit 5 for 30-120 seconds to obtain a hydroxyl acrylic resin aqueous dispersion; preferably, the proportion of the deionized water in the hydroxyl acrylic resin aqueous dispersion is 40-56%;

and 5: and enabling the hydroxyl acrylic resin aqueous dispersion to enter the receiving system 6, and enabling the hydroxyl acrylic resin aqueous dispersion to enter a storage tank after being cooled to 25-35 ℃ by the material mixed liquid primary preheating system/dispersion cooling system 8.

Preferably, the pressure of the polymerization reaction in the step 2 and the neutralization reaction in the step 3 is controlled to be 1-4 MPa by a back pressure device.

In the invention, the first material mixed solution is preheated to 40-50 ℃ in the first mixer 1-1 through the material mixed solution first-stage preheating system/dispersion cooling system 8, the first material mixed solution is continuously conveyed to the polymerization reaction unit 3 through the continuous conveying system 2 and the material mixed solution second-stage preheating system/resin cooling system 7, and the first material mixed solution is preheated to 100-130 ℃ through the material mixed solution second-stage preheating system/resin cooling system 7.

In the invention, the monomers in the step 1 comprise a hydroxyl monomer, a carboxyl monomer, an optional (methyl) acrylate monomer and styrene, wherein based on the total monomer mass, the hydroxyl monomer accounts for 12-39%, the carboxyl monomer accounts for 1.3-3%, the (methyl) acrylate monomer accounts for 10-80%, and the styrene accounts for 5-50%.

Preferably, the hydroxyl monomer is one or more of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate and hydroxybutyl methacrylate; the carboxyl monomer is at least one of acrylic acid and methacrylic acid; the (methyl) acrylate monomer is one or more of methyl (methyl) acrylate, ethyl (methyl) acrylate, isooctyl (methyl) acrylate, butyl (methyl) acrylate and isobornyl (methyl) acrylate.

Based on the total monomer mass, the hydroxyl monomer accounts for 12-39%, so that the hydroxyl value of the hydroxyl acrylic resin aqueous dispersion can be ensured to be 60-150 mg KOH/g. If the hydroxyl monomer is too little, the situation of chain scission blocking is easy to occur when the resin aqueous dispersion and the curing agent are crosslinked, if the hydroxyl monomer is too much, the crosslinking density of the groups is improved, the contact between the hydroxyl and isocyanate is difficult, and residual hydroxyl exists in the system, so that the water resistance of a paint film is reduced.

Based on the total monomer mass, the carboxyl monomer accounts for 1.3-3%. When the amount of the carboxyl monomer is too high, although the hydrophilicity of the resin is increased and the difficulty of resin dispersion is reduced, the water resistance of the polyurethane paint film is reduced, and when the amount of the carboxyl monomer is too low, the stability of the obtained aqueous dispersion is reduced and the phenomenon of delamination is easy to occur.

Based on the total monomer mass, the (methyl) acrylate monomer accounts for 10-80%, and the styrene accounts for 5-50%.

In the invention, the solvent in the step 1 is one or more of propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol butyl ether, propylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, toluene, xylene, No. 100 solvent oil, butyl acetate, isobutyl acetate, n-butyl alcohol and isobutyl alcohol, and the boiling point of the solvent is 110-170 ℃; solvents with lower boiling points and hydrophilicity and lipophilicity, such as propylene glycol methyl ether, propylene glycol ethyl ether and propylene glycol monomethyl ether acetate, are preferred, so as to avoid the problem that the residual time is too long due to too slow volatilization of the solvents in the product application process, and the influence on the product application is avoided.

In the invention, the initiator in the step 1 is one or more of di-tert-butyl peroxide, di-tert-amyl peroxide, diisopropyl peroxide, di-tert-butyl dicumyl peroxide and tert-butyl cumyl peroxide, and the decomposition temperature of the initiator is 170-200 ℃ when the half-life period of the initiator is 1min, so that the initiator can be rapidly decomposed to generate free radicals at the reaction temperature, the chain initiation process is shortened, and the polymeric molecules with shorter molecular chains are obtained.

Preferably, one specific embodiment of the step 1 comprises: enabling part of monomers to enter a first mixer 1-1, mixing and preheating to 40-50 ℃ to obtain a first material mixed solution; enabling the solvent and the initiator to enter a second mixer 1-2 for mixing to obtain a second material mixed solution; and the other part of the monomer, the solvent and the initiator enter a third mixer 1-3 to be mixed to obtain a third material mixed solution. The mass of the carboxyl monomer in the first material mixed solution accounts for 40-60% of the total mass of the carboxyl monomer, and the mass of the hydroxyl monomer, (methyl) acrylate monomer and styrene respectively accounts for 80-90% of the total mass of the corresponding various monomers; the mass of the solvent and the initiator in the second material mixed solution accounts for 80-90% of the total mass of the solvent and the total mass of the initiator; the mass of the carboxyl monomer in the third material mixed solution accounts for 40-60% of the total mass of the carboxyl monomer, the mass of the hydroxyl monomer, (methyl) acrylate monomer and styrene respectively accounts for 10-20% of the total mass of the corresponding monomers, and the mass of the solvent and the initiator respectively accounts for 10-20% of the total mass of the solvent and the initiator.

The purpose of adding the third material mixed solution is to feed the monomer and the initiator in a segmented manner, so that the production process is safer and more controllable, and in addition, the specific gravity of the carboxyl monomer in the third material mixed solution is higher than that of the carboxyl monomer in the first material mixed solution, so that the arrangement density of carboxyl at the tail end of a molecular chain can be improved, and the middle front end of the molecular chain also has more uniform carboxyl distribution.

Preferably, one specific embodiment of the step 2 comprises: the first material mixed liquor and the second material mixed liquor are conveyed to a first microchannel reactor (namely a polymerization reaction unit 3) of a continuous channel reactor comprising a first microchannel reactor, a first static tubular reactor, a second microchannel reactor and a second static tubular reactor which are sequentially connected in series through the continuous conveying system 2, and contact and mix with a third material mixed liquor continuously conveyed to the second microchannel reactor through the continuous conveying system 2 to continuously react through the first static tubular reactor, so that the hydroxyl acrylic resin is obtained at a discharge port of the second static tubular reactor.

In the invention, a neutralization reagent for neutralizing the resin is an amine compound, the neutralization reagent in the step 3 is one or more of N, N-dimethylethanolamine, N-methyl monoethanolamine, N-methyldiethanolamine, ethanolamine, diethanolamine and triethanolamine, and the neutralization degree of the hydroxyl acrylic resin is 70-90%.

As the amino group on the amine compound is easy to be oxidized, and the acrylate group is hydrolyzed under the conditions of overhigh dosage of a neutralizing reagent and higher temperature to cause the quality loss of a coating film, the operation of the conventional neutralizing process is to cool the resin to 60-90 ℃ in advance before neutralization. On the contrary, a continuous production mode is adopted in the invention, the reaction system is not contacted with air, a back pressure device connected behind the neutralization unit 4 ensures the pressure of the system, the local excess condition of a neutralization reagent and the volatilization and oxidation of amine compounds are avoided, the temperature in the neutralization process can be increased to a certain extent, and in order to ensure the smooth and rapid completion of the neutralization process and the comprehensive utilization of energy, the temperature in the neutralization process is 100-130 ℃.

The resin and the neutralizing agent enter a tube bundle type reactor with a strong mixing function at a high flow rate, and under the condition of too short retention time, carboxyl on a polymerization chain segment of the hydroxyl acrylic resin and the neutralizing agent do not react sufficiently, so that the water solubility of the resin is reduced, and the residual amine compound can influence the product quality and the environment, so that the retention time of the neutralization process adopted by the invention is 10-60 s. In addition, under the condition of over high neutralization degree, acrylate groups in the resin are easy to hydrolyze, the performance of a coating film is influenced, the water resistance is reduced, and under the condition of over low neutralization degree, the water solubility of the neutralized resin is low, and the subsequent dispersion process is influenced, so that the neutralization degree of the hydroxy acrylic resin adopted in the invention is 70-90%.

In order to obtain the hydroxyl acrylic resin aqueous dispersion with small particle size and uniform dispersion, the resin dispersion process adopts a tube bundle type reactor with a strong mixing function, and the dispersion process is carried out at the temperature of 60-80 ℃. Namely, the neutralized resin and deionized water enter a tube bundle reactor according to a certain proportion, in the process of material flowing, a water phase and an oil phase are continuously sheared to be strongly mixed, the resin and the water are in a state of more water and less oil at the moment of entering the mixer, and a transient water-in-oil state exists only under the condition that the mixing is not uniform at the initial stage of mixing, so that the viscosity of the dispersion generally tends to be reduced in the process of continuous dispersion, and an unobvious viscosity increasing stage exists only at the initial stage of dispersion. The hydroxyl acrylic resin obtained by the polymerization reaction unit 3 has narrow molecular weight distribution and relatively low viscosity, and the temperature in the dispersion stage is increased, so that the dispersion resistance is greatly reduced, the dispersion process is easier to carry out, in addition, due to the existence of a small amount of hydrophilic and lipophilic solvents, the water phase and the oil phase are easier to disperse, and under the condition, the resin and deionized water can rapidly disperse in the flowing process through a tube bundle type reactor at a higher flow speed, so that the obtained water dispersion has small particle size, is more uniform and better in stability, and the time for dispersion is shortened to a certain extent. The inventor finds that when the retention time in the dispersion process is too short and less than 30s, the obtained aqueous dispersion has poor dispersibility and poor stability, and needs to prolong the retention time in the dispersion process to a certain extent in order to improve the dispersibility of the aqueous dispersion, so that the retention time in the dispersion process is 30-120 s. Preferably, the proportion of the deionized water in the hydroxyl acrylic resin aqueous dispersion is 40-56%.

When the hydroxyl acrylic resin aqueous dispersion obtained by the dispersing unit 5 is stored, the storage temperature is not too high, if the storage temperature is higher than 35 ℃, water on the surface layer of a product evaporates to form a glue film with poor solubility on the surface, so that the product is wasted, and meanwhile, the storage temperature of the aqueous dispersion obtained by the invention is not too low, and the storage temperature is too low to damage the structure of the product, so that the storage temperature adopted by the invention is 25-35 ℃. The water dispersion obtained by the dispersion unit 5 enters a receiver of the receiving unit 6, and then passes through a tubular mixer with a jacket for heat exchange, so that the secondary dispersion effect can be achieved while uniform cooling is realized, and the cooled dispersion continuously flows into a storage tank for temporary storage.

More specifically, in the invention, the outlets of the blenders 1-1, 1-2 and 1-3 in the mixing system 1 are connected with the inlet of the continuous conveying system 2, the outlet of the continuous conveying system 2 is connected with the inlet of the microchannel reactor in the polymerization reaction unit 3, the resin outlet of the static tubular reactor in the polymerization reaction unit 3 is connected with the resin inlet of the tubular heat exchanger (i.e., the material mixed liquid second-stage preheating system/resin cooling system 7), the resin outlet of the tubular heat exchanger is connected with the resin inlet of the neutralizing unit 4, the resin outlet of the neutralizing unit 4 is connected with the resin inlet of the dispersing unit 5, the dispersion outlet of the dispersing unit 5 is connected with the dispersion inlet of the receiver in the receiving unit 6, and the outlet of the receiver is connected with the inlet of the storage tank in the receiving system.

An outlet of a heat exchange jacket of a receiver in the receiving system 6 is connected with an inlet of a circulating pump (namely, a material mixed liquid first-stage preheating system/dispersion cooling system 8), an outlet of the circulating pump is connected with an inlet of the heat exchange jacket of the first mixer 1-1, and an outlet of the heat exchange jacket of the first mixer 1-1 is connected with an inlet of the heat exchange jacket of the receiver; the outlet of the first mixer is connected with the material mixed liquid inlet of the tubular heat exchanger (namely, the material mixed liquid second-stage preheating system/resin cooling system 7), the material mixed liquid outlet of the tubular heat exchanger is connected with the inlet of the polymerization reaction unit 3, and the heat exchange channel of the continuous channel reactor in the polymerization reaction unit 3 is connected with the reaction temperature control system 9.

The present invention will be described in further detail with reference to specific examples, which include but are not limited to the following examples, and any modifications made to the details and forms of the technical solutions of the present invention without departing from the meaning and scope of the present application fall within the scope of the present invention.

In the present invention, the solid content is in mass% unless otherwise specified.

The determination of the solid content is carried out according to GB/T1725-2007; the viscosity is measured by adopting an NDJ-1 type rotary viscometer according to GB/T2794-2013; the acid value is measured according to GB/T2895-2008; the hydroxyl value is measured by reference to GB/T12008.3-2009; the particle size is measured according to GB/T11175-2002; VOC was determined with reference to GB/T23985-2009.

Example 1

7.5 parts by weight (hereinafter, the same) of methyl acrylate, 17 parts by weight of styrene, 11.24 parts by weight of ethyl acrylate, 18.73 parts by weight of isooctyl acrylate, 12.67 parts by weight of hydroxyethyl acrylate, and 0.44 part by weight of acrylic acid were uniformly mixed by a first mixer 1-1 to obtain a first material mixed solution. And uniformly mixing 12 parts of propylene glycol methyl ether and 1.6 parts of di-tert-butyl peroxide in a second mixer 1-2 to obtain a second material mixed solution. 1.87 parts of methyl acrylate, 4.25 parts of styrene, 2.8 parts of ethyl acrylate, 4.68 parts of isooctyl acrylate, 3.17 parts of hydroxyethyl acrylate, 0.66 part of acrylic acid, 3 parts of propylene glycol methyl ether and 0.4 part of di-tert-butyl peroxide are uniformly mixed in a third mixer 1-3 to obtain a third material mixed solution. The first mixer 1-1 is a stirring kettle with a jacket for heat exchange, and the second mixer 1-2 and the third mixer 1-3 are stirring kettles.

The first material mixed liquor is first preheated to 43 ℃ in the first mixer 1-1 through a circulating pump of a first-stage preheating system/dispersion cooling system 8 of the material mixed liquor, and then enters a tubular heat exchanger of a second-stage preheating system/resin cooling system 7 of the material mixed liquor through the continuous conveying system 2 at a flow rate of 68kg/h to be secondarily preheated to 113 ℃. The preheated first material mixed liquor and the second material mixed liquor simultaneously and continuously enter a first microchannel reactor of a polymerization reaction unit 3 (comprising two microchannel reactors and two static tubular reactors), react in the first microchannel reactor and the first static tubular reactor at the temperature of 190 ℃ and under the pressure of 2.6MPa, reaction liquid flows through the first microchannel reactor and the first static tubular reactor, then is mixed with third material mixed liquor entering a second microchannel reactor and continuously reacts in the second microchannel reactor and the second static tubular reactor, and the total residence time of the first material mixed liquor, the second material mixed liquor and the third material mixed liquor in the polymerization reaction unit 3 is 14 min. And obtaining hydroxyl acrylic resin at the outlet of the second static tubular reactor, continuously cooling the hydroxyl acrylic resin to 115 ℃ through the tubular heat exchanger, then enabling the hydroxyl acrylic resin to enter a tubular reactor serving as a neutralization unit 4, reacting the hydroxyl acrylic resin with N, N-dimethylethanolamine entering the tubular reactor at the same time at the flow rate of 0.95kg/h for 15s, enabling the neutralized resin and deionized water at the flow rate of 115.5kg/h to enter another tubular reactor serving as a dispersion unit 5 at the same time, rapidly dispersing the neutralized resin for 73s at the temperature of 67 ℃, enabling the obtained aqueous dispersion to continuously enter a tubular mixer serving as a receiving system 6, uniformly cooling the obtained aqueous dispersion to 28 ℃, and then enabling the obtained aqueous dispersion to enter a storage tank for temporary storage.

Wherein the primary preheating of the material mixed liquor and the temperature reduction of the dispersion are carried out by using the same heat exchange medium through the circulating pump, the secondary preheating of the material mixed liquor and the temperature reduction of the resin are carried out simultaneously in the tubular heat exchanger, and the polymerization reaction unit 3 controls the reaction temperature through a reaction temperature control system 9.

The obtained hydroxyl acrylic resin water dispersion has the solid content of 40 percent, the viscosity of 400cP, the acid value of 10mg KOH/g, the hydroxyl value of 90mg KOH/g, the average particle size of 97nm, the neutralization degree of 70 percent, the monomer residual quantity of 0.2 percent and the VOC content of 6.9mL/100 g.

Example 2

7.86 parts of methyl methacrylate, 14.62 parts of styrene, 11.78 parts of butyl acrylate, 19.64 parts of isooctyl acrylate, 10 parts of hydroxyethyl methacrylate, 7 parts of hydroxypropyl acrylate and 1.32 parts of methacrylic acid are uniformly mixed by a first mixer 1-1 to obtain a first material mixed solution. 11.2 parts of propylene glycol ethyl ether and 2.4 parts of di-tert-butyl peroxide are uniformly mixed in a second mixer 1-2 to obtain a second material mixed solution. 1.39 parts of methyl methacrylate, 2.58 parts of styrene, 2.08 parts of butyl acrylate, 3.47 parts of isooctyl acrylate, 3 parts of hydroxyethyl methacrylate, 1.32 parts of methacrylic acid, 2.8 parts of propylene glycol ethyl ether and 0.6 part of di-tert-butyl peroxide are uniformly mixed in a third mixer 1-3 to obtain a third material mixed solution. The first mixer 1-1 is a stirring kettle with a jacket for heat exchange, and the second mixer 1-2 and the third mixer 1-3 are stirring kettles.

The first material mixed liquor is preheated to 47 ℃ in the first mixer 1-1 through a circulating pump of a first-stage preheating system/dispersion cooling system 8 of the material mixed liquor in a first stage, and then enters a tubular heat exchanger of a second-stage preheating system/resin cooling system 7 of the material mixed liquor in a second-stage preheating system/resin cooling system 7 of the continuous conveying system at a flow rate of 73.1kg/h to be preheated to 124 ℃ in a second stage. The preheated first material mixed liquor and the second material mixed liquor simultaneously and continuously enter a first microchannel reactor of a polymerization reaction unit 3 (comprising two microchannel reactors and two static tubular reactors), react in the first microchannel reactor and the first static tubular reactor at the temperature of 200 ℃ and the pressure of 3.2MPa, reaction liquid flows through the first microchannel reactor and the first static tubular reactor, then is mixed with third material mixed liquor entering a second microchannel reactor and continuously reacts in the second microchannel reactor and the second static tubular reactor, and the total residence time of the first material mixed liquor, the second material mixed liquor and the third material mixed liquor in the polymerization reaction unit 3 is 11 min. And obtaining hydroxyl acrylic resin at the outlet of the second static tubular reactor, continuously cooling the hydroxyl acrylic resin to 122 ℃ through the tubular heat exchanger, then enabling the hydroxyl acrylic resin to enter a tubular reactor serving as a neutralization unit 4, reacting the hydroxyl acrylic resin with N-methyl monoethanolamine simultaneously entering the tubular reactor at the flow rate of 1.84kg/h for 10s, enabling the neutralized resin and deionized water at the flow rate of 108.9kg/h to simultaneously enter another tubular reactor serving as a dispersion unit 5, rapidly dispersing the neutralized resin for 30s at the temperature of 76 ℃, enabling the obtained aqueous dispersion to continuously enter a tubular mixer serving as a receiving system 6, uniformly cooling the obtained aqueous dispersion to 32 ℃, and then enabling the obtained aqueous dispersion to enter a storage tank for temporary storage.

Wherein the primary preheating of the material mixed liquor and the temperature reduction of the dispersion are carried out by using the same heat exchange medium through the circulating pump, the secondary preheating of the material mixed liquor and the temperature reduction of the resin are carried out simultaneously in the tubular heat exchanger, and the polymerization reaction unit 3 controls the reaction temperature through a reaction temperature control system 9.

The obtained aqueous dispersion of the hydroxyacrylic resin had a solid content of 42%, a viscosity of 500cP, an acid value of 20mg KOH/g, a hydroxyl value of 100mg KOH/g, an average particle diameter of 105nm, a neutralization degree of 80%, a monomer residue of 0.1%, and a VOC content of 6.6mL/100 g.

Example 3

6.77 parts of ethyl methacrylate, 22.43 parts of styrene, 16.92 parts of butyl methacrylate, 10.15 parts of isooctyl acrylate, 9.35 parts of hydroxypropyl acrylate, 12.2 parts of hydroxyethyl methacrylate and 1 part of acrylic acid are uniformly mixed by a first mixer 1-1 to obtain a first material mixed solution. 8.8 parts of propylene glycol butyl ether and 3.2 parts of di-tert-amyl peroxide are uniformly mixed in a second mixer 1-2 to obtain a second material mixed solution. 0.75 part of ethyl methacrylate, 2.49 parts of styrene, 1.88 parts of butyl methacrylate, 1.13 parts of isooctyl acrylate, 2.4 parts of hydroxypropyl acrylate, 0.66 part of acrylic acid, 2.2 parts of propylene glycol butyl ether and 0.8 part of di-tert-amyl peroxide are uniformly mixed in a third mixer 1-3 to obtain a third material mixed solution. The first mixer 1-1 is a stirring kettle with a jacket for heat exchange, and the second mixer 1-2 and the third mixer 1-3 are stirring kettles.

The first material mixed liquor is preheated to 42 ℃ in the first mixer 1-1 through a circulating pump of a first-stage preheating system/dispersion cooling system 8 of the material mixed liquor in a first stage, and then enters a tubular heat exchanger of a second-stage preheating system/resin cooling system 7 of the material mixed liquor in a second-stage preheating to 117 ℃ through a continuous conveying system 2 at a flow rate of 80.1 kg/h. The preheated first material mixed liquor and the second material mixed liquor simultaneously and continuously enter a first microchannel reactor of a polymerization reaction unit 3 (comprising two microchannel reactors and two static tubular reactors), react in the first microchannel reactor and the first static tubular reactor at the temperature of 180 ℃ and under the pressure of 1.7MPa, reaction liquid flows through the first microchannel reactor and the first static tubular reactor, then is mixed with third material mixed liquor entering a second microchannel reactor and continuously reacts in the second microchannel reactor and the second static tubular reactor, and the total residence time of the first material mixed liquor, the second material mixed liquor and the third material mixed liquor in the polymerization reaction unit 3 is 7 min. And obtaining hydroxyl acrylic resin at the outlet of the second static tubular reactor, continuously cooling the hydroxyl acrylic resin to 108 ℃ through the tubular heat exchanger, then enabling the hydroxyl acrylic resin to enter a tubular reactor serving as a neutralization unit 4, reacting the hydroxyl acrylic resin with N-methyldiethanolamine entering the tubular reactor at the same time at the flow rate of 2.47kg/h for 20s, enabling the neutralized resin and deionized water at the flow rate of 107.4kg/h to enter another tubular reactor serving as a dispersion unit 5 at the same time, rapidly dispersing the neutralized resin for 62s at the temperature of 66 ℃, enabling the obtained aqueous dispersion to continuously enter a tubular mixer serving as a receiving system 6, uniformly cooling the obtained aqueous dispersion to 28 ℃, and then enabling the obtained aqueous dispersion to enter a storage tank for temporary storage.

Wherein the primary preheating of the material mixed liquor and the temperature reduction of the dispersion are carried out by using the same heat exchange medium through the circulating pump, the secondary preheating of the material mixed liquor and the temperature reduction of the resin are carried out simultaneously in the tubular heat exchanger, and the polymerization reaction unit 3 controls the reaction temperature through a reaction temperature control system 9.

The obtained aqueous dispersion of a hydroxyacrylic resin had a solid content of 44%, a viscosity of 670cP, an acid value of 15mg KOH/g, a hydroxyl value of 120mg KOH/g, an average particle diameter of 107nm, a neutralization degree of 90%, a monomer residue of 0.2%, and a VOC content of 5.2mL/100 g.

Example 4

4.37 parts of isobornyl acrylate, 22.53 parts of styrene, 6.55 parts of ethyl acrylate, 10.9 parts of isooctyl methacrylate, 13.18 parts of hydroxypropyl methacrylate, 11.24 parts of hydroxybutyl acrylate and 0.8 part of methacrylic acid are uniformly mixed by a first mixer 1-1 to obtain a first material mixed solution. 10.2 parts of propylene glycol methyl ether acetate and 1.7 parts of di-tert-amyl peroxide are uniformly mixed in a second mixer 1-2 to obtain a second material mixed solution. 1.1 parts of isobornyl acrylate, 5.63 parts of styrene, 1.64 parts of ethyl acrylate, 2.73 parts of isooctyl methacrylate, 6.1 parts of hydroxypropyl methacrylate, 1.2 parts of methacrylic acid, 1.8 parts of propylene glycol methyl ether acetate and 0.3 part of di-tert-amyl peroxide are uniformly mixed in a third mixer 1-3 to obtain a third material mixed solution. The first mixer 1-1 is a stirring kettle with a jacket for heat exchange, and the second mixer 1-2 and the third mixer 1-3 are stirring kettles.

The first material mixed liquor is preheated to 40 ℃ in the first mixer 1-1 in the first stage by a circulating pump of a first-stage preheating system/dispersion cooling system 8 of the material mixed liquor, and then enters a tubular heat exchanger of a second-stage preheating system/resin cooling system 7 of the material mixed liquor in the second-stage preheating system/resin cooling system 1 at the flow rate of 70.4kg/h through a continuous conveying system 2 to be preheated to 101 ℃ in the second stage. The preheated first material mixed liquor and the second material mixed liquor simultaneously and continuously enter a first micro-channel reactor of a polymerization reaction unit 3 (comprising two micro-channel reactors and two static tubular reactors), react in the first micro-channel reactor and the first static tubular reactor at the temperature of 170 ℃ and the pressure of 1MPa, reaction liquid flows through the first micro-channel reactor and the first static tubular reactor, then is mixed with third material mixed liquor entering a second micro-channel reactor and continuously reacts in the second micro-channel reactor and the second static tubular reactor, and the total residence time of the first material mixed liquor, the second material mixed liquor and the third material mixed liquor in the polymerization reaction unit 3 is 20 min. And obtaining hydroxyl acrylic resin at the outlet of the second static tubular reactor, continuously cooling the hydroxyl acrylic resin to 100 ℃ through the tubular heat exchanger, then enabling the hydroxyl acrylic resin to enter a tubular reactor serving as a neutralization unit 4, reacting the hydroxyl acrylic resin with ethanolamine which simultaneously enters the tubular reactor at the flow rate of 1.06kg/h for 35s, enabling the neutralized resin and deionized water at the flow rate of 93.65kg/h to simultaneously enter another tubular reactor serving as a dispersion unit 5, rapidly dispersing the neutralized resin for 120s at the temperature of 60 ℃, continuously enabling the obtained aqueous dispersion to enter a tubular mixer serving as a receiving system 6, uniformly cooling the obtained aqueous dispersion to 25 ℃, and then enabling the obtained aqueous dispersion to enter a storage tank for temporary storage.

Wherein the primary preheating of the material mixed liquor and the temperature reduction of the dispersion are carried out by using the same heat exchange medium through the circulating pump, the secondary preheating of the material mixed liquor and the temperature reduction of the resin are carried out simultaneously in the tubular heat exchanger, and the polymerization reaction unit 3 controls the reaction temperature through a reaction temperature control system 9.

The obtained aqueous dispersion of a hydroxyacrylic resin had a solid content of 46%, a viscosity of 800cP, an acid value of 15mg KOH/g, a hydroxyl value of 135mg KOH/g, an average particle diameter of 92nm, a neutralization degree of 75%, a monomer residue of 0.25%, and a VOC content of 6.1mL/100 g.

Example 5

8.28 parts of methyl acrylate, 3.83 parts of styrene, 12.43 parts of ethyl acrylate, 20.7 parts of isooctyl acrylate, 29.5 parts of hydroxybutyl acrylate and 1 part of acrylic acid are uniformly mixed by a first mixer 1-1 to obtain a first material mixed solution. 8.5 parts of ethylene glycol ethyl ether and 2.6 parts of diisopropyl peroxide are uniformly mixed in a second mixer 1-2 to obtain a second material mixed solution. 1.46 parts of methyl acrylate, 0.68 part of styrene, 2.19 parts of ethyl acrylate, 3.65 parts of isooctyl acrylate, 5.2 parts of hydroxybutyl acrylate, 1 part of acrylic acid, 1.5 parts of ethylene glycol ethyl ether and 0.45 part of diisopropyl peroxide are uniformly mixed in a third mixer 1-3 to obtain a third material mixed solution. The first mixer 1-1 is a stirring kettle with a jacket for heat exchange, and the second mixer 1-2 and the third mixer 1-3 are stirring kettles.

The first material mixed liquor is preheated to 40 ℃ in the first mixer 1-1 in the first stage by a circulating pump of a first-stage preheating system/dispersion cooling system 8 of the material mixed liquor, and then enters a tubular heat exchanger of a second-stage preheating system/resin cooling system 7 of the material mixed liquor in the second-stage preheating system/resin cooling system at the flow rate of 76.5kg/h through a continuous conveying system 2 to be preheated to 109 ℃ in the second stage. The preheated first material mixed liquor and the second material mixed liquor simultaneously and continuously enter a first microchannel reactor of a polymerization reaction unit 3 (comprising two microchannel reactors and two static tubular reactors), react in the first microchannel reactor and the first static tubular reactor at 175 ℃ and under the pressure of 1.3MPa, after flowing through the first microchannel reactor and the first static tubular reactor, reaction liquid is mixed with third material mixed liquor entering a second microchannel reactor and continuously reacts in the second microchannel reactor and the second static tubular reactor, and the total residence time of the first material mixed liquor, the second material mixed liquor and the third material mixed liquor in the polymerization reaction unit 3 is 9 min. And obtaining hydroxyl acrylic resin at the outlet of the second static tubular reactor, continuously cooling the hydroxyl acrylic resin to 101 ℃ through the tubular heat exchanger, then enabling the hydroxyl acrylic resin to enter a tubular bundle reactor serving as a neutralization unit 4, reacting with diethanolamine simultaneously entering the tubular bundle reactor at the flow rate of 2.52kg/h for 80s, enabling the neutralized resin and deionized water at the flow rate of 90.8kg/h to simultaneously enter another tubular bundle reactor serving as a dispersion unit 5, rapidly dispersing for 58s at the temperature of 62 ℃, enabling the obtained aqueous dispersion to continuously enter a tubular mixer serving as a receiving system 6, uniformly cooling to 26 ℃, and then enabling the obtained aqueous dispersion to enter a storage tank for temporary storage.

Wherein the primary preheating of the material mixed liquor and the temperature reduction of the dispersion are carried out by using the same heat exchange medium through the circulating pump, the secondary preheating of the material mixed liquor and the temperature reduction of the resin are carried out simultaneously in the tubular heat exchanger, and the polymerization reaction unit 3 controls the reaction temperature through a reaction temperature control system 9.

The obtained hydroxyl acrylic resin water dispersion has the solid content of 48 percent, the viscosity of 1000cP, the acid value of 18mg KOH/g, the hydroxyl value of 150mg KOH/g, the average particle diameter of 113nm, the neutralization degree of 85 percent, the monomer residual quantity of 0.3 percent and the VOC content of 5.1mL/100 g.

Example 6

9.98 parts of methyl methacrylate, 13.77 parts of styrene, 14.97 parts of ethyl acrylate, 24.95 parts of isooctyl methacrylate, 14.26 parts of hydroxyethyl acrylate and 1.4 parts of methacrylic acid are uniformly mixed by a first mixer 1-1 to obtain a first material mixed solution. 8.5 parts of ethylene glycol monoethyl ether acetate and 3.4 parts of diisopropyl peroxide are uniformly mixed in a second mixer 1-2 to obtain a second material mixed solution. 1.1 parts of methyl methacrylate, 1.53 parts of styrene, 1.66 parts of ethyl acrylate, 2.77 parts of isooctyl methacrylate, 1.6 parts of hydroxyethyl acrylate, 1 part of methacrylic acid, 1.5 parts of ethylene glycol ethyl ether acetate and 0.6 part of diisopropyl peroxide are uniformly mixed in a third mixer 1-3 to obtain a third material mixed solution. The first mixer 1-1 is a stirring kettle with a jacket for heat exchange, and the second mixer 1-2 and the third mixer 1-3 are stirring kettles.

The first material mixed liquor is preheated to 42 ℃ in the first mixer 1-1 through a circulating pump of a first-stage preheating system/dispersion cooling system 8 of the material mixed liquor in a first stage, and then enters a tubular heat exchanger of a second-stage preheating system/resin cooling system 7 of the material mixed liquor in a second-stage preheating to 114 ℃ through a continuous conveying system 2 at a flow rate of 81 kg/h. The preheated first material mixed liquor and the second material mixed liquor simultaneously and continuously enter a first microchannel reactor of a polymerization reaction unit 3 (which comprises two microchannel reactors and two static tubular reactors), react in the first microchannel reactor and the first static tubular reactor at 185 ℃ and under the pressure of 1.5MPa, reaction liquid flows through the first microchannel reactor and the first static tubular reactor, then is mixed with third material mixed liquor entering a second microchannel reactor and continuously reacts in the second microchannel reactor and the second static tubular reactor, and the total residence time of the first material mixed liquor, the second material mixed liquor and the third material mixed liquor in the polymerization reaction unit 3 is 4 min. And obtaining hydroxyl acrylic resin at the outlet of the second static tubular reactor, continuously cooling the hydroxyl acrylic resin to 108 ℃ through the tubular heat exchanger, then enabling the hydroxyl acrylic resin to enter a tubular bundle reactor serving as a neutralization unit 4, reacting the hydroxyl acrylic resin with triethanolamine simultaneously entering the tubular bundle reactor at the flow rate of 2.85kg/h for 100s, enabling the neutralized resin and deionized water at the flow rate of 84kg/h to simultaneously enter another tubular bundle reactor serving as a dispersion unit 5, rapidly dispersing the neutralized resin for 53s at the temperature of 66 ℃, continuously enabling the obtained aqueous dispersion to enter a tubular mixer serving as a receiving system 6, uniformly cooling the obtained aqueous dispersion to 28 ℃, and then enabling the obtained aqueous dispersion to enter a storage tank for temporary storage.

Wherein the primary preheating of the material mixed liquor and the temperature reduction of the dispersion are carried out by using the same heat exchange medium through the circulating pump, the secondary preheating of the material mixed liquor and the temperature reduction of the resin are carried out simultaneously in the tubular heat exchanger, and the polymerization reaction unit 3 controls the reaction temperature through a reaction temperature control system 9.

The obtained aqueous dispersion of a hydroxyacrylic resin had a solid content of 50%, a viscosity of 900cP, an acid value of 18mg KOH/g, a hydroxyl value of 90mg KOH/g, an average particle diameter of 117nm, a neutralization degree of 70%, a monomer residue of 0.18%, and a VOC content of 5.3mL/100 g.

Example 7

1.3 parts of methyl acrylate, 3.2 parts of styrene, 15.5 parts of isooctyl acrylate, 25.8 parts of butyl acrylate, 16 parts of hydroxyethyl methacrylate and 0.66 part of acrylic acid are uniformly mixed by a first mixer 1-1 to obtain a first material mixed solution. 10 parts of propylene glycol methyl ether, 6 parts of No. 100 oil, 1 part of di-tert-butyl peroxide and 0.6 part of di-tert-amyl peroxide are uniformly mixed in a second mixer 1-2 to obtain a second material mixed solution. 2.58 parts of methyl acrylate, 0.8 part of styrene, 3.87 parts of isooctyl acrylate, 6.45 parts of butyl acrylate, 4 parts of hydroxyethyl methacrylate, 1 part of acrylic acid, 4 parts of propylene glycol methyl ether and 0.4 part of di-tert-amyl peroxide are uniformly mixed in a third mixer 1-3 to obtain a third material mixed solution. The first mixer 1-1 is a stirring kettle with a jacket for heat exchange, and the second mixer 1-2 and the third mixer 1-3 are stirring kettles.

The first material mixed liquor is preheated to 40 ℃ in the first mixer 1-1 in the first stage by a circulating pump of a first-stage preheating system/dispersion cooling system 8 of the material mixed liquor, and then enters a tubular heat exchanger of a second-stage preheating system/resin cooling system 7 of the material mixed liquor in the second-stage preheating system/resin cooling system at the flow rate of 68.8kg/h through the continuous conveying system 2 to be preheated to 115 ℃ in the second stage. The preheated first material mixed liquor and the second material mixed liquor simultaneously and continuously enter a first microchannel reactor of a polymerization reaction unit 3 (comprising two microchannel reactors and two static tubular reactors), react in the first microchannel reactor and the first static tubular reactor at the temperature of 195 ℃ and the pressure of 1.9MPa, reaction liquid flows through the first microchannel reactor and the first static tubular reactor, then is mixed with third material mixed liquor entering a second microchannel reactor and continuously reacts in the second microchannel reactor and the second static tubular reactor, and the total residence time of the first material mixed liquor, the second material mixed liquor and the third material mixed liquor in the polymerization reaction unit 3 is 10 min. And obtaining hydroxyl acrylic resin at the outlet of the second static tubular reactor, continuously cooling the hydroxyl acrylic resin to 117 ℃ through the tubular heat exchanger, then enabling the hydroxyl acrylic resin to enter a tubular reactor serving as a neutralization unit 4, reacting the hydroxyl acrylic resin with N, N-dimethylethanolamine entering the tubular reactor at the same time at the flow rate of 1.53kg/h for 40s, enabling the neutralized resin and deionized water at the flow rate of 103kg/h to enter another tubular reactor serving as a dispersion unit 5 at the same time, rapidly dispersing for 71s at the temperature of 71 ℃, enabling the obtained aqueous dispersion to continuously enter a tubular mixer serving as a receiving system 6, uniformly cooling to 30 ℃, and then enabling the aqueous dispersion to enter a storage tank for temporary storage.

Wherein the primary preheating of the material mixed liquor and the temperature reduction of the dispersion are carried out by using the same heat exchange medium through the circulating pump, the secondary preheating of the material mixed liquor and the temperature reduction of the resin are carried out simultaneously in the tubular heat exchanger, and the polymerization reaction unit 3 controls the reaction temperature through a reaction temperature control system 9.

The obtained hydroxyl acrylic resin water dispersion has the solid content of 40 percent, the viscosity of 300cP, the acid value of 15mg KOH/g, the hydroxyl value of 100mg KOH/g, the average particle size of 94nm, the neutralization degree of 80 percent, the monomer residual quantity of 0 percent and the VOC content of 9.8mL/100 g.

Example 8

4.41 parts of methyl methacrylate, 30.67 parts of styrene, 6.62 parts of butyl methacrylate, 11.03 parts of isooctyl acrylate, 20.35 parts of hydroxypropyl acrylate and 1 part of methacrylic acid are uniformly mixed by a first mixer 1-1 to obtain a first material mixed solution. 7.8 parts of propylene glycol butyl ether, 3 parts of butyl acetate and 2.7 parts of di-tert-butyl peroxide are uniformly mixed in a second mixer 1-2 to obtain a second material mixed solution. 0.78 part of methyl methacrylate, 5.41 parts of styrene, 1.17 parts of butyl methacrylate, 1.95 parts of isooctyl acrylate, 3.6 parts of hydroxypropyl acrylate, 1 part of methacrylic acid, 1.2 parts of propylene glycol butyl ether and 1 part of di-tert-butyl peroxide are uniformly mixed in a third mixer 1-3 to obtain a third material mixed solution. The first mixer 1-1 is a stirring kettle with a jacket for heat exchange, and the second mixer 1-2 and the third mixer 1-3 are stirring kettles.

The first material mixed liquor is preheated to 48 ℃ in the first mixer 1-1 in the first stage by a circulating pump of the first stage preheating system/dispersion cooling system 8 of the material mixed liquor, and then enters the tubular heat exchanger of the second stage preheating system/resin cooling system 7 of the material mixed liquor in the second stage preheating system/resin cooling system at the flow rate of 74.8kg/h through the continuous conveying system 2 for second stage preheating to 124 ℃. The preheated first material mixed liquor and the second material mixed liquor simultaneously and continuously enter a first microchannel reactor of a polymerization reaction unit 3 (comprising two microchannel reactors and two static tubular reactors), react in the first microchannel reactor and the first static tubular reactor at the temperature of 205 ℃ and the pressure of 3.4MPa, reaction liquid flows through the first microchannel reactor and the first static tubular reactor, then is mixed with third material mixed liquor entering a second microchannel reactor and continuously reacts in the second microchannel reactor and the second static tubular reactor, and the total residence time of the first material mixed liquor, the second material mixed liquor and the third material mixed liquor in the polymerization reaction unit 3 is 9 min. And obtaining hydroxyl acrylic resin at the outlet of the second static tubular reactor, continuously cooling the hydroxyl acrylic resin to 125 ℃ through the tubular heat exchanger, then enabling the hydroxyl acrylic resin to enter a tubular bundle reactor serving as a neutralization unit 4, reacting the hydroxyl acrylic resin with diethanolamine simultaneously entering the tubular bundle reactor at the flow rate of 1.86kg/h for 60s, enabling the neutralized resin and deionized water at the flow rate of 90.5kg/h to simultaneously enter another tubular bundle reactor serving as a dispersion unit 5, rapidly dispersing the neutralized resin for 46s at the temperature of 76 ℃, enabling the obtained aqueous dispersion to continuously enter a tubular mixer serving as a receiving system 6, uniformly cooling the obtained aqueous dispersion to 31 ℃, and then enabling the obtained aqueous dispersion to enter a storage tank for temporary storage.

Wherein the primary preheating of the material mixed liquor and the temperature reduction of the dispersion are carried out by using the same heat exchange medium through the circulating pump, the secondary preheating of the material mixed liquor and the temperature reduction of the resin are carried out simultaneously in the tubular heat exchanger, and the polymerization reaction unit 3 controls the reaction temperature through a reaction temperature control system 9.

The obtained aqueous dispersion of the hydroxyacrylic resin had a solid content of 46%, a viscosity of 620cP, an acid value of 15mg KOH/g, a hydroxyl value of 120mg KOH/g, an average particle diameter of 93nm, a neutralization degree of 90%, a monomer residual amount of 0.14%, and a VOC content of 6mL/100 g.

Example 9

6.6 parts of ethyl methacrylate, 17.42 parts of styrene, 9.89 parts of butyl methacrylate, 16.49 parts of isooctyl methacrylate, 27.48 parts of hydroxypropyl methacrylate and 0.88 part of acrylic acid are uniformly mixed by a first mixer 1-1 to obtain a first material mixed solution. 7.8 parts of propylene glycol butyl ether, 3 parts of dimethylbenzene and 3.6 parts of di-tert-butyl peroxide are uniformly mixed in a second mixer 1-2 to obtain a second material mixed solution. 0.73 part of ethyl methacrylate, 1.94 parts of styrene, 1.83 parts of butyl methacrylate, 1.1 parts of isooctyl methacrylate, 3 parts of hydroxypropyl methacrylate, 0.6 part of acrylic acid, 1.2 parts of propylene glycol butyl ether and 0.4 part of di-tert-butyl peroxide are uniformly mixed in a third mixer 1-3 to obtain a third material mixed solution. The first mixer 1-1 is a stirring kettle with a jacket for heat exchange, and the second mixer 1-2 and the third mixer 1-3 are stirring kettles.

The first material mixed liquor is preheated to 50 ℃ in the first mixer 1-1 in the first stage by a circulating pump of a first-stage preheating system/dispersion cooling system 8 of the material mixed liquor, and then enters a tubular heat exchanger of a second-stage preheating system/resin cooling system 7 of the material mixed liquor in the second-stage preheating system/resin cooling system 7 of the continuous conveying system at the flow rate of 79.2kg/h for second-stage preheating to 125 ℃. The preheated first material mixed liquor and the second material mixed liquor simultaneously and continuously enter a first micro-channel reactor of a polymerization reaction unit 3 (comprising two micro-channel reactors and two static tubular reactors), react in the first micro-channel reactor and the first static tubular reactor at the temperature of 210 ℃ and under the pressure of 4MPa, reaction liquid flows through the first micro-channel reactor and the first static tubular reactor, then is mixed with third material mixed liquor entering a second micro-channel reactor and continuously reacts in the second micro-channel reactor and the second static tubular reactor, and the total residence time of the first material mixed liquor, the second material mixed liquor and the third material mixed liquor in the polymerization reaction unit 3 is 3 min. And obtaining hydroxyl acrylic resin at the outlet of the second static tubular reactor, continuously cooling the hydroxyl acrylic resin to 115 ℃ through the tubular heat exchanger, then enabling the hydroxyl acrylic resin to enter a tubular bundle reactor serving as a neutralization unit 4, reacting the hydroxyl acrylic resin with diethanolamine simultaneously entering the tubular bundle reactor at the flow rate of 1.36kg/h for 90s, enabling the neutralized resin and deionized water at the flow rate of 87.7kg/h to simultaneously enter another tubular bundle reactor serving as a dispersion unit 5, rapidly dispersing the neutralized resin for 95s at the temperature of 80 ℃, enabling the obtained aqueous dispersion to continuously enter a tubular mixer serving as a receiving system 6, uniformly cooling the obtained aqueous dispersion to 35 ℃, and then enabling the obtained aqueous dispersion to enter a storage tank for temporary storage.

Wherein the primary preheating of the material mixed liquor and the temperature reduction of the dispersion are carried out by using the same heat exchange medium through the circulating pump, the secondary preheating of the material mixed liquor and the temperature reduction of the resin are carried out simultaneously in the tubular heat exchanger, and the polymerization reaction unit 3 controls the reaction temperature through a reaction temperature control system 9.

The obtained aqueous dispersion of the hydroxyacrylic resin had a solid content of 48%, a viscosity of 700cP, an acid value of 13mg KOH/g, a hydroxyl value of 135mg KOH/g, an average particle diameter of 101nm, a neutralization degree of 75%, a monomer residue of 0.1%, and a VOC content of 6.2mL/100 g.

Example 10

1.36 parts of methyl methacrylate, 36 parts of styrene, 3.4 parts of butyl methacrylate, 2.04 parts of isooctyl methacrylate, 27.75 parts of hydroxybutyl acrylate and 0.88 part of methacrylic acid are uniformly mixed by a first mixer 1-1 to obtain a first material mixed solution. 5 parts of propylene glycol butyl ether, 3 parts of n-butanol and 2.4 parts of di-tert-amyl peroxide are uniformly mixed in a second mixer 1-2 to obtain a second material mixed solution. 0.34 part of methyl methacrylate, 9 parts of styrene, 0.85 part of butyl methacrylate, 0.51 part of isooctyl methacrylate, 6.9 parts of hydroxybutyl acrylate, 0.88 part of methacrylic acid, 2 parts of propylene glycol butyl ether and 0.6 part of di-tert-amyl peroxide are uniformly mixed in a third mixer 1-3 to obtain a third material mixed solution. The first mixer 1-1 is a stirring kettle with a jacket for heat exchange, and the second mixer 1-2 and the third mixer 1-3 are stirring kettles.

The first material mixed liquor is preheated to 41 ℃ in the first mixer 1-1 in the first stage by a circulating pump of a first-stage preheating system/dispersion cooling system 8 of the material mixed liquor, and then enters a tubular heat exchanger of a second-stage preheating system/resin cooling system 7 of the material mixed liquor through a continuous conveying system 2 at a flow rate of 72kg/h for second-stage preheating to 113 ℃. The preheated first material mixed liquor and the second material mixed liquor simultaneously and continuously enter a first microchannel reactor of a polymerization reaction unit 3 (which comprises two microchannel reactors and two static tubular reactors), react in the first microchannel reactor and the first static tubular reactor at 185 ℃ and under the pressure of 1.5MPa, reaction liquid flows through the first microchannel reactor and the first static tubular reactor, then is mixed with third material mixed liquor entering a second microchannel reactor and continuously reacts in the second microchannel reactor and the second static tubular reactor, and the total residence time of the first material mixed liquor, the second material mixed liquor and the third material mixed liquor in the polymerization reaction unit 3 is 6 min. And obtaining hydroxyl acrylic resin at the outlet of the second static tubular reactor, continuously cooling the hydroxyl acrylic resin to 107 ℃ through the tubular heat exchanger, then enabling the hydroxyl acrylic resin to enter a tubular bundle reactor serving as a neutralization unit 4, reacting the hydroxyl acrylic resin with diethanol amine entering the tubular bundle reactor at the same time at the flow rate of 1.55kg/h for 38s, enabling the neutralized resin and deionized water at the flow rate of 108.4kg/h to enter another tubular bundle reactor serving as a dispersion unit 5 at the same time, rapidly dispersing the neutralized resin for 78s at the temperature of 64 ℃, enabling the obtained aqueous dispersion to continuously enter a tubular mixer serving as a receiving system 6, uniformly cooling the obtained aqueous dispersion to 27 ℃, and then enabling the obtained aqueous dispersion to enter a storage tank for temporary storage.

Wherein the primary preheating of the material mixed liquor and the temperature reduction of the dispersion are carried out by using the same heat exchange medium through the circulating pump, the secondary preheating of the material mixed liquor and the temperature reduction of the resin are carried out simultaneously in the tubular heat exchanger, and the polymerization reaction unit 3 controls the reaction temperature through a reaction temperature control system 9.

The obtained hydroxyl acrylic resin water dispersion has the solid content of 44%, the viscosity of 850cP, the acid value of 13mg KOH/g, the hydroxyl value of 150mg KOH/g, the average particle size of 114nm, the neutralization degree of 85%, the monomer residual quantity of 0.2% and the VOC content of 4.7mL/100 g.

Comparative example

The comparative example prepared the aqueous dispersion of hydroxyacrylic resin using the same material ratio as in example 7 under the conditions of conventional kettle-type operation optimized, and the specific procedure was as follows: adding 14 parts of propylene glycol methyl ether and 6 parts of No. 100 oil into a reaction kettle with a stirring device and a heat exchange device, heating to 140 ℃, dropwise adding a mixed solution of 1.3 parts of methyl acrylate, 3.2 parts of styrene, 15.5 parts of isooctyl acrylate, 25.8 parts of butyl acrylate, 16 parts of hydroxyethyl methacrylate, 0.66 part of acrylic acid and 1.6 parts of di-tert-amyl peroxide into the reaction kettle, and controlling the dropwise adding to be finished within 2 hours. After the dripping and heat preservation is finished for 2 hours, continuing to drip a mixed solution of 2.58 parts of methyl acrylate, 0.8 part of styrene, 3.87 parts of isooctyl acrylate, 6.45 parts of butyl acrylate, 4 parts of hydroxyethyl methacrylate, 1 part of acrylic acid and 0.4 part of di-tert-amyl peroxide, finishing the dripping for 30min, and preserving the heat for 1 hour. And (3) cooling the resin to 70 ℃, adding 1.53 parts of N-methyldiethanolamine at one time for neutralization for 20min under the condition of 2000r/min, and adding 103 parts of deionized water at one time for dispersion for 20min under the condition of 2000r/min after neutralization to obtain the hydroxyl acrylic resin aqueous dispersion.

The aqueous dispersion of a hydroxyacrylic resin obtained by the above-mentioned conventional reaction tank-type operation had a solid content of 39.2%, a viscosity of 3100cP, an acid value of 15mg KOH/g, a hydroxyl value of 100mg KOH/g, an average particle diameter of 169nm, a neutralization degree of 90%, a monomer-remaining amount of 0.96%, and a VOC content of 11.4mL/100 g.

Compared with example 7, under the condition of the same material ratio, the viscosity and the average particle diameter of the dispersion in the comparative example are obviously larger, in addition, the solid content of the dispersion is slightly reduced, the VOC content is correspondingly increased, and the monomer residue is higher.