Method for regulating molecular weight change of electronic grade acrylic resin

Abstract

This invention provides a method for controlling the molecular weight change of electronic-grade acrylic resins. The method utilizes mixture A for the polymerization reaction process and mixture D for controlling the reaction concentration to regulate the polymerization reaction. Mixture A includes monomer A, initiator, and organic solvent A; mixture B includes monomer B, organic solvent B, and a dehydrating agent. The specific steps of the method are as follows: S1: Under an inert gas atmosphere, mixture A is added to the reactor, and the temperature is raised to initiate the polymerization reaction; S2: Mixture B is added according to the reaction consumption rate, and during the polymerization reaction, the inert gas is continuously circulated in the reactor. This invention achieves the production of electronic-grade acrylic resins by employing a starved reactor, which on the one hand precisely controls the reaction concentration to regulate the molecular weight, and on the other hand utilizes a dehydrating agent to remove the heat of the reaction system and the moisture heated by azeotropic reaction with the dehydrating agent into the inert atmosphere.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and specifically to a method for regulating the molecular weight change of electronic-grade acrylic resins. Background Technology

[0002] Traditional processes for preparing bottom anti-reflective coating materials require the addition of monomers and initiators to a solution or emulsion, followed by a prolonged polymerization reaction under conditions such as heating and a nitrogen atmosphere, to achieve the desired molecular weight of acrylic resin. However, this process is problematic in the early stages due to the long initiator induction time and the unavoidable chain growth and termination reactions. Furthermore, the initial reaction is difficult to control, potentially leading to the formation of numerous short-chain polymers. Since the polymerization reaction is random copolymerization, traditional processes introduce new impurity ions and fail to meet electronic grade requirements.

[0003] In the prior art, various methods are disclosed to control molecular weight in order to prepare corresponding polymer materials. For example, CN1950401A discloses a method for preparing macromonomers by free radical initiation of aqueous emulsion polymerization in a polymerization reactor using at least one olefinic unsaturated monomer. This method utilizes a novel CCTP method with a hydrophobic Co chelate catalyst in an aqueous emulsion to form macromonomers. Therefore, when using this hydrophobic Co catalyst, this method allows for the preparation of very low molecular weight macromonomers using a significantly reduced amount of Co catalyst (compared to the amount of Co catalyst required to achieve comparable molecular weight reduction to date). Patent CN114044843A discloses that by using a single polymer as a base and reacting it with various functional alcohols, the molecular weight distribution can be well controlled, resulting in photoresist resins with controllable molecular weight and narrow distribution. Patent CN116323729A discloses a method for manufacturing carboxyl-containing resins with excellent batch-to-batch performance stability and controllable molecular weight. The control method includes the following steps: controlling the moisture content of a first liquid containing reaction product A, obtained by reacting an epoxy compound (a) with an unsaturated monobasic acid (b) in an organic solvent, to obtain a second liquid containing reaction product A; adding a polybasic acid dianhydride (c) and a polybasic acid monohydric acid (d) to the aforementioned second liquid containing reaction product A and reacting them to obtain a carboxyl-containing resin. Patent CN106432582A relates to a polymerization method for controlling the molecular weight distribution of acrylates using reactant concentration. By pre-adding a portion of monomer and solvent to the reactor and controlling the initiator concentration, free radical polymerization proceeds smoothly and slowly. Simultaneously, monomer is added dropwise to maintain the monomer concentration in the reactor within a stable range, ensuring the internal environment of the polymerization reaction remains essentially unchanged, thereby obtaining an acrylate pressure-sensitive adhesive with a narrow molecular weight distribution. Patent CN112694558A provides a method for controlling the molecular weight of methacrylic resin, comprising the following steps: placing the monomer of methacrylic resin in a glass bottle; adding a photoinitiator to the glass bottle and mixing it evenly to obtain a prepolymer, wherein the photoinitiator is miscible with the monomer of the methacrylic resin and the prepolymer does not contain a solvent; and irradiating the prepolymer in the glass bottle with light of a certain intensity to cause the prepolymer to undergo a photopolymerization reaction to obtain methacrylic resin. Summary of the Invention

[0004] The purpose of this invention is to provide a method for controlling the molecular weight change of electronic-grade acrylic resins. By employing a starved reactor, the reaction concentration is precisely controlled to regulate the molecular weight, while a dehydrating agent is used to remove the heat from the reaction system and the hot moisture that azeotropically enters the inert atmosphere with the dehydrating agent, thereby obtaining electronic-grade acrylic resins.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] On one hand, the present invention provides a method for regulating the molecular weight change of electronic grade acrylic resin, wherein the method uses a mixture A for the polymerization reaction process and a mixture B for controlling the reaction concentration to regulate the polymerization reaction;

[0007] The mixture A comprises monomer A, initiator and organic solvent A;

[0008] The mixture B comprises monomer B, organic solvent B, and water-removing agent.

[0009] Furthermore, the specific steps of the method are as follows:

[0010] S1: Under an inert gas atmosphere, mixture A is added to the reactor, and the temperature is raised to initiate a polymerization reaction;

[0011] S2: Mixture B is added according to the reaction consumption rate. During the polymerization reaction, the inert gas in the reactor is kept in continuous flow.

[0012] Furthermore, the location where the mixture B is added is inside the polymerization reaction system, and there are various ways to do so, such as using a replenishment tube to add the mixture B below the liquid surface of the polymerization reaction system.

[0013] Further, the mixture A is prepared as follows: monomer A, initiator, and organic solvent A are mixed uniformly under an inert gas atmosphere. Before being fed into the reactor, mixture A is in an unpolymerized form or a partially polymerized form.

[0014] Further, the mixture B is prepared as follows: monomer B, organic solvent B and dehydrating agent are mixed evenly under an inert gas atmosphere.

[0015] Furthermore, the concentration ratio of monomer A in mixture A to monomer B in mixture B is 1:1 to 10.

[0016] Furthermore, the mass ratio of the initiator to the dehydrating agent is 1 to 10:1.

[0017] Furthermore, the mass ratio of the monomer to the dehydrating agent is 100 to 1000:1, wherein the mass of the monomer is the sum of the masses of monomer A and monomer B.

[0018] Further, the volume ratio of the monomer to the organic solvent is 1:3 to 10, wherein the volume of the organic solvent is the sum of the volumes of organic solvent A and organic solvent B, and the mass of the monomer is the sum of the masses of monomer A and monomer B. The volume ratio of organic solvent A to organic solvent B is 1:1 to 10.

[0019] Furthermore, the reaction consumption rate is the replenishment rate of mixture B, which is the concentration change rate, i.e., 0.1% to 10% / min.

[0020] Furthermore, the polymerization reaction is carried out at a temperature of 50–90°C.

[0021] Furthermore, the reaction time of the polymerization reaction is 4 to 8 hours.

[0022] Furthermore, the initiator can be appropriately selected from existing azo-based free radical initiators, peroxide-based free radical initiators, redox-based free radical initiators, etc. Examples of azo-based free radical initiators include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylpentanitrile), and 2,2'-azobismethoxyisoheptanenitrile. Examples of peroxide-based free radical initiators include diisopropyl peroxide dicarbonate, bis(2-ethylhexyl) peroxide dicarbonate, and diethoxyethyl peroxide dicarbonate, etc.; perester compounds such as tert-butyl peroxyneodecanate, α-cumyl peroxyneodecanate, and tert-butyl peroxyneodecanate; acetylcyclohexylsulfonyl peroxide and diisobutyryl peroxide; and 2,4,4-trimethylpentyl-2-peroxyphenoxyacetic acid ester, etc.

[0023] Furthermore, the dehydrating agent can be selected from one or more of the following in the prior art: benzene, toluene, n-propanol, isobutanol, ethanol, isopropanol, chloroethanol, cyclohexane, chloroform, and carbon tetrachloride. The dehydrating agent can be any organic solvent that does not participate in the polymerization reaction.

[0024] Further, the organic solvent is selected from one or more of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, ethyl 2-hydroxypropionate, methyl 2-hydroxy-3-methylbutyrate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate, N,N-dimethylformamide, and N-methylpyrrolidone. The organic solvent can be any organic solvent that does not participate in the polymerization reaction.

[0025] Further, the monomer is selected from one or more of methyl methacrylate, butyl acrylate, 2-methyl-2-adamantyl methacrylate, butyrolactone methacrylate, 2-hydroxyethyl methacrylate, ethyl acrylate, butyl acrylate, isooctyl acrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, 2-carboxy-6-norbornyl lactone-5-methacrylate, 3-hydroxy-1-adamantyl methacrylate, 2-ethyl-2-adamantyl methacrylate, 2-hydroxyethyl methacrylate, and hydroxyethyl acrylate.

[0026] Furthermore, the inert gas is selected from gases such as nitrogen and argon that do not participate in the reaction under polymerization conditions. The inert gas is continuously flowing during the polymerization process, meaning that room-temperature inert gas continuously enters the reactor, while inert gas carrying water-carrying agents and moisture, and possessing a certain amount of heat, is continuously extracted from the reactor. Furthermore, the flow rate of the inert gas is 1–100 mL / min. The continuously flowing inert atmosphere not only removes heat from the reaction system but also carries away the water-carrying agents and moisture that have azeotropically entered the inert atmosphere.

[0027] Furthermore, the reactor can be any reactor, reaction device, or reaction system that achieves the starvation reaction, such as a starvation reactor.

[0028] Furthermore, the specific process of the method is as follows:

[0029] Pretreatment: Mixture A is prepared as follows: Under a nitrogen atmosphere, monomer A, initiator and organic solvent A are mixed evenly and set aside; Mixture B is prepared as follows: Under a nitrogen atmosphere, monomer B, organic solvent B and dehydrating agent are mixed evenly and set aside.

[0030] S1: Under a nitrogen atmosphere, mixture A is added to the starved reactor, the temperature is raised to 50-90℃, and the polymerization reaction is carried out at a stirring speed of 90-390 r / min (preferably 290 r / min) for 4-8 hours;

[0031] S2: Using a replenishment tube, mixture B is added to the polymerization reaction system below the liquid level at a reaction consumption rate of 0.1% to 10% / min. During the polymerization reaction, nitrogen gas is continuously circulated in the reactor. After the reaction is completed, electronic grade acrylic resin is obtained.

[0032] On the other hand, the acrylic resins, macromonomers, or graft copolymers prepared by the method of the present invention are used in coating applications.

[0033] On the one hand, the acrylic resins, macromonomers, or graft copolymers prepared by the method of the present invention are used in the field of graphic art applications, including film coatings and printing varnishes.

[0034] On the one hand, the use of acrylic resins, macromonomers, or graft copolymers prepared by the method described in this invention in adhesive applications.

[0035] This invention employs precise control of reactant concentrations to regulate product molecular weight, and ensures the use of inert gas and a dehydrating agent to control the reaction system temperature, thereby achieving the production of electronic-grade acrylic resins, macromonomers, or graft copolymers. Specifically, it involves:

[0036] ① Mixture A enters the reactor to initiate the polymerization reaction; Mixture B is added either by maintaining the same rate of replenishment as consumption or by directly introducing it into the polymerization reaction system. The method of adding mixture B consumes a certain amount of heat while simultaneously controlling the rate of polymerization, thus controlling the overall heat release of the polymerization reaction.

[0037] ②The water-removing agent of the present invention absorbs the water generated in the polymerization reaction system after being added to the system, so that the reaction system solution forms a microemulsion; the concentration of monomer expanding micelles is higher than that of polymer particles, so the possibility of free radicals in the reaction system entering the particles and terminating is smaller; on the other hand, the continuously flowing inert atmosphere not only removes the heat of the reaction system, but also removes the water-removing agent and water that are azeotropically added to the inert atmosphere.

[0038] Based on the combined effects of ① and ②, not only can the reaction temperature of the polymerization system be effectively controlled at 50–90℃ (preferably 70–90℃), but the molecular weight of the polymer in the polymerization reaction can also be controlled, which is beneficial for the production of electronic-grade acrylic resins.

[0039] The experimental environment conditions of this application embodiment are that the experiments are conducted in a clean room environment, and the process parameters also require that there be no metal devices.

[0040] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0041] 1. This invention utilizes the control of the feeding rate and feeding position of mixture B to regulate the molecular weight, thereby maintaining the dispersion.

[0042] 2: This invention utilizes a water-carrying agent and a circulating inert atmosphere to not only remove heat from the reaction system but also remove moisture from the reaction system, suppressing the generation of side reactions, while simultaneously controlling the temperature and reaction rate of the reaction system. Detailed Implementation

[0043] The technical solution of the present invention will be illustrated below with examples. The scope of protection sought by the present invention includes, but is not limited to, the following embodiments.

[0044] Preparation Examples

[0045] Mixture A is prepared as follows: Under a nitrogen atmosphere, monomer A, initiator and organic solvent A are mixed evenly and set aside.

[0046] Mixture B is prepared as follows: Under a nitrogen atmosphere, monomer B, organic solvent B, and dehydrating agent are mixed evenly and set aside.

[0047] S1: Under a nitrogen atmosphere, mixture A is added to the starved reactor, the temperature is raised to 50-90℃, and the polymerization reaction is carried out at a stirring speed of 290r / min for 4-8h.

[0048] S2: Using a replenishment tube, mixture B is added to the polymerization reaction system below the liquid surface at a reaction consumption rate of 0.1%–10% / min. During the polymerization reaction, nitrogen gas is continuously circulated in the reactor at a rate of 0.1 mL / min. After the reaction is completed, electronic-grade acrylic resin is obtained.

[0049] Example 1

[0050] Monomer A is methyl methacrylate; initiator is 2,2'-azobisisobutyronitrile; organic solvent A is ethylene glycol monomethyl ether; monomer B is methyl methacrylate; organic solvent B is ethylene glycol monomethyl ether;

[0051] The concentration ratio of monomer A in mixture A to monomer B in mixture B is 1:1; the volume ratio of monomer to organic solvent is 1:3; and the volume ratio of organic solvent A to organic solvent B is 1:1.

[0052] A method for controlling the molecular weight change of electronic-grade acrylic resins includes the following steps:

[0053] Pretreatment: Mixture A is prepared as follows: Under a nitrogen atmosphere, monomer A, initiator and organic solvent A are mixed evenly and set aside; Mixture B is prepared as follows: Under a nitrogen atmosphere, monomer B and organic solvent B are mixed evenly and set aside.

[0054] Resin synthesis: Under a nitrogen atmosphere, mixture A was added to a starved reactor, which was then placed in an oil bath. The rotor speed was adjusted to 290 r / min and the oil bath temperature to 60℃. Two pipes, a and b, were left in the starved reactor. Pipe a was connected below the liquid surface, and pipe b was placed above the liquid surface. Mixture B was added to the starved reactor at room temperature through port a at a rate of 1% / min. At the same time, gas was extracted from the top of the reactor through pipe b. Nitrogen gas was kept flowing through both devices during the reaction. The reaction time was 6 hours. After the reaction was completed, samples were extracted and subjected to GPC analysis.

[0055] Example 2

[0056] The difference from Example 1 is that the concentration ratio of monomer A in mixture A to monomer B in mixture B is 1:2; the acceleration rate is 0.8% / min.

[0057] Example 3

[0058] The difference from Example 1 is that the concentration ratio of monomer A in mixture A to monomer B in mixture B is 1:3; the acceleration rate is 1.2% / min.

[0059] Example 4

[0060] The difference from Example 1 is that the concentration ratio of monomer A in mixture A to monomer B in mixture B is 1:4; the acceleration rate is 3% / min.

[0061] Example 5

[0062] The difference from Example 1 is as follows:

[0063] The mixture B is prepared as follows: under a nitrogen atmosphere, monomer B, organic solvent B, and dehydrating agent are mixed evenly; the dehydrating agent is toluene.

[0064] The mass ratio of monomer to dehydrating agent is 100:1, the concentration ratio of monomer A in mixture A to monomer B in mixture B is 1:1, and the replenishment rate is 0.4% / min.

[0065] Example 6

[0066] The difference from Example 1 is as follows:

[0067] The mixture B is prepared as follows: under a nitrogen atmosphere, monomer B, organic solvent B, and dehydrating agent are mixed evenly; the dehydrating agent is toluene.

[0068] The mass ratio of monomer to dehydrating agent is 100:1, the concentration ratio of monomer A in mixture A to monomer B in mixture B is 1:2, and the replenishment rate is 0.8% / min.

[0069] Examples 7-16

[0070] The difference from Example 1 is as follows:

[0071]

[0072]

[0073]

[0074] Comparative Example 1

[0075] The difference from Example 1 is as follows:

[0076] The preparation method using traditional acrylic resins includes the following steps:

[0077] The monomer, organic solvent, and initiator were placed into the starved reactor at once. The starved reactor was then placed in an oil bath. The rotor speed was adjusted to 290 r / min and the oil bath temperature was set to 60°C. During the reaction, the apparatus was kept in a nitrogen atmosphere for 6 hours. After the reaction was completed, samples were taken for GPC sampling.

[0078] Comparative Example 2

[0079] The difference from Example 1 is as follows:

[0080] The preparation method using traditional acrylic resins includes the following steps:

[0081] The monomer, organic solvent, initiator, and dehydrating agent were placed into the starved reactor at once. The starved reactor was then placed in an oil bath. The rotor speed was adjusted to 290 r / min and the oil bath temperature was set to 60°C. During the reaction, the device was kept in a nitrogen atmosphere for 6 hours. After the reaction was completed, samples were taken for GPC sampling.

[0082] Comparative Example 3

[0083] The difference from Example 1 is as follows:

[0084] The preparation method using traditional acrylic resins includes the following steps:

[0085] The monomer, organic solvent, initiator, and dehydrating agent were placed into the starved reactor at once. The starved reactor was then placed in an oil bath. The rotor speed was adjusted to 290 r / min and the oil bath temperature was set to 60°C. During the reaction, the device was kept in a nitrogen atmosphere with continuous nitrogen flow. The reaction time was 6 hours. After the reaction was completed, samples were taken for GPC sampling.

[0086] Product sampling inspection for each embodiment:

[0087] The experimental results are shown in Table 1 below:

[0088] Table 1. Polymerization results under different conditions

[0089] Example Weight-average molecular weight / g·mol polydispersity Temperature rise reading Example 1 31701 2.56 7℃ Example 2 26584 2.44 6℃ Example 3 25957 2.25 5℃ Example 4 22467 2.21 4℃ Example 5 21891 2.17 3℃ Example 6 20794 2.13 3℃ Comparative Example 1 67234 3.21 10℃ Comparative Example 2 56379 2.84 8℃ Comparative Example 3 51056 2.75 8℃

[0090] In the reaction process of Examples 1 to 4, no dehydrating agent was used. The test results show that by adding mixture B and controlling the addition method, the molecular weight can be controlled relatively accurately, and the temperature rise effect can also be controlled to a certain extent.

[0091] By comparing Examples 1-2 with Examples 5-6, it can be seen that after adding the dehydrating agent, the temperature rise in the reactor is further controlled, and the molecular weight of the resulting polymer is also further controlled.

[0092] By comparing the results of Examples 1 and 6 with those of Comparative Examples 1 to 3, it can be seen that the molecular weight of the traditional method changes with the increase of temperature and the change of concentration. The method of this application can indeed accelerate the polymerization of monomers, and the reaction temperature is effectively controlled, which can slow down the polymerization explosion. At the same time, by adding mixture B, the polymerization reaction proceeds smoothly and the polymerization molecular weight is controlled more accurately.

[0093] The experimental environment of this application embodiment is a clean room environment, and the process parameters also require no metal devices; the purified electronic grade resin is detected by ICP-MS-MS, and the metal ion content is less than 50 ppb and the chloride ion content is less than 10 ppm.

[0094] Comparative Example 4

[0095] The difference from Example 1 is that the experimental environment was a standard laboratory, and the reaction vessel and sampling pipes a and b had low requirements for metal impurities. The purified ordinary-grade resin was analyzed by ICP-MS-MS, and the metal ion content was less than 10 ppm, the chloride ion content was less than 500 ppm, the product's Mw = 31701, and PDI = 2.56.

[0096] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for regulating the molecular weight change of electronic-grade acrylic resins, characterized in that, The method uses mixture A for the polymerization reaction process and mixture B for controlling the reaction concentration to regulate the polymerization reaction; The mixture A comprises monomer A, initiator and organic solvent A; The mixture B comprises monomer B and organic solvent B; The specific steps of the method are as follows: Pretreatment: Mixture A is prepared as follows: Under a nitrogen atmosphere, monomer A, initiator and organic solvent A are mixed evenly and set aside; Mixture B is prepared as follows: Under a nitrogen atmosphere, monomer B, organic solvent B and dehydrating agent are mixed evenly and set aside. S1: Under a nitrogen atmosphere, mixture A is added to the starved reactor, the temperature is raised to 50~90℃, and the polymerization reaction is carried out at a stirring speed of 90~390r / min for 4~8h. S2: Using a replenishment tube, mixture B is added to the surface of the polymerization reaction system at a reaction consumption rate of 0.1%~10% / min. During the polymerization reaction, nitrogen gas is continuously circulated in the reactor. After the reaction is completed, electronic grade acrylic resin is obtained. The monomers A and B are methyl methacrylate, the concentration ratio of monomer A to monomer B is 1:4, the acceleration rate is 3% / min, the initiator is 2,2'-azobisisobutyronitrile, the organic solvent A is ethylene glycol monomethyl ether, and the organic solvent B is ethylene glycol monomethyl ether.

2. The method according to claim 1, characterized in that, The mass ratio of the initiator to the dehydrating agent is 1~10:

1.

3. The method according to claim 1, characterized in that, The mass ratio of the monomer to the dehydrating agent is 100~1000:1, wherein the mass of the monomer is the sum of the masses of monomer A and monomer B.

4. The method according to claim 1, characterized in that, The volume ratio of the monomer to the organic solvent is 1:3 to 10, wherein the volume of the organic solvent is the sum of the volumes of organic solvent A and organic solvent B, and the mass of the monomer is the sum of the masses of monomer A and monomer B.

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