Methods for producing polymer and resin composition

Abstract

The present invention provides methods for efficiently producing a polymer and a resin composition, which can be operated by a small number of unskilled operators and require less labor of the operators. A method for producing a polymer according to the present invention includes a polymerization step in which a polymer raw material containing a monomer (a) is supplied into a polymerization reactor and is subjected to a polymerization reaction to obtain a polymer (A). The polymerization step includes a polymerization reaction control process in which a state variable that indicates the behavior of the polymerization reaction is controlled by adjusting manipulated variables for controlling the polymerization reaction. The manipulated variables and the state variable are continuous or intermittent operation data obtained from a measurement device and other incidental facilities that are attached to a production facility. The polymerization reaction control process includes: a process (I) for predicting the transition of the state variable from the present to the future; and a process (II) for determining and executing a manipulated variable and a manipulated amount that are to be adjusted from the present to the future on the basis of data obtained in the process (I).

Description

Methods for producing polymers and resin compositions

[0001] This invention relates to a method for producing polymers and resin compositions.

[0002] Generally, in polymer production, the polymerization reaction in a polymerization reactor is controlled by adjusting operational variables that control the polymerization reaction, using state variables that represent the behavior of the polymerization reaction as indicators. Since these state variables change continuously moment by moment due to disturbances such as fluctuations in the temperature and supply rate of the monomers that are the raw materials for the polymer, and ambient temperature, the operator monitors the state variables and adjusts the operational variables as appropriate to control the polymerization reaction. For example, in the continuous production of vinyl polymers, first, polymer raw materials (vinyl monomers, etc.) are supplied to the polymerization reactor, and the polymer production conditions are operated according to past operating conditions to carry out the polymerization reaction. Next, in this operating state, the current value of the state variable is compared with the preset target value of the state variable, and the difference between the current value and the target value is confirmed. Then, the operational variables are adjusted to correct this difference.

[0003] However, the above manufacturing method requires an operator to monitor state variables and adjust control variables. In addition, quality evaluation of the final resin composition and inspection of the equipment that embodies the polymer and resin composition manufacturing method must be carried out in parallel, which requires a great deal of effort and makes it difficult to efficiently manufacture polymers and resin compositions. Furthermore, when adjusting control variables, the operator must determine and execute the amount and timing of manipulation of the control variables using past state variables as indicators, but it is difficult to accurately predict how these operations will change the state variables in the future. As a result, if the amount or timing of manipulation of the control variables is not appropriate, the polymerization reaction may become unstable, resulting in defective products, or the polymerization reaction may become uncontrollable, leading to runaway polymerization. This poses a significant risk in terms of quality and safety, and also results in a high psychological burden on the operator. For these reasons, controlling the polymerization reaction requires many years of experience and intuition, and it is necessary to assign a highly skilled and experienced operator to the task.

[0004] In order to solve the above problems, a method for producing a polymer that controls a polymerization reaction has been proposed by creating a simulation program for predicting a polymerization reaction and calculating and executing set values of manipulated variables thereby. For example, in Patent Document 1, a method for determining polymerization conditions by performing a virtual experiment in a simulation program using a polymerization reaction rate constant obtained by conducting an experiment in advance is disclosed.

[0005] Japanese Patent Application Laid-Open No. 2004-91688

[0006] In the method for producing a polymer disclosed in the above patent document, although it is possible to efficiently calculate polymerization conditions, disturbances such as fluctuations in the temperature and supply amount of a monomer which is a raw material of the polymer and external air temperature exist in production equipment, and thus it is necessary to correct the polymerization conditions in consideration of these. Further, when the polymerization conditions are corrected, the degree of influence on the polymerization reaction changes moment by moment due to changes in the polymerization reaction rate and the residence time in the system from the polymerization reaction until a polymer is obtained, and thus it is necessary to correct the polymerization conditions again. Therefore, in production by production equipment, it is necessary for a skilled operator to appropriately adjust the manipulated variable in consideration of the degree of influence on the polymerization reaction due to the above disturbance factors and the control delay due to the polymerization reaction rate and the residence time, and it has not been possible to efficiently obtain a polymer.

[0007] Therefore, an object of the present invention is to provide an efficient method for producing a polymer and a resin composition that can be operated by a small number of unskilled operators and that requires little labor of the operators.

[0008] As a result of intensive studies to solve the above problems, the present inventors have found that in a polymerization reaction control process that controls state variables representing the behavior of a polymerization reaction by adjusting manipulated variables for controlling the polymerization reaction, a process (I) for predicting the transition of state variables from the present to the future and a process (II) for determining and executing the manipulated variable and the operation amount to be adjusted from the present to the future based on the data obtained in the process (I) can solve the above problems, and have completed the present invention.

[0009] That is, the present invention has the following configuration: (1) A method for producing a polymer, comprising a polymerization step of supplying a polymer raw material containing monomer (a) to a polymerization reactor and causing a polymerization reaction to obtain a polymer (A), wherein the polymerization step includes a polymerization reaction control process that controls state variables representing the behavior of the polymerization reaction by adjusting operational variables that control the polymerization reaction, the operational variables and state variables being continuous or intermittent operating data obtained from measuring instruments and other ancillary equipment attached to the manufacturing facility, and the polymerization reaction control process comprising a process (I) of predicting the changes in state variables from the present to the future, and a process (II) of determining and executing operational variables and operational amounts to be adjusted from the present to the future based on the data obtained in process (I), the method for producing a polymer, (2) The method for producing a polymer according to (1), wherein the operational variable is at least one selected from the group consisting of a set pressure in the polymerization reactor, a rate at which polymer (A) is discharged from the polymerization reactor, a set value for the amount of polymerization initiator supplied, and a set value for the amount of chain transfer agent supplied, the method for producing a polymer, according to (1), (3) The method for producing a polymer according to (1) or (2), wherein the monomer (a) comprises at least one selected from the group consisting of an aromatic vinyl monomer (a1) and a vinyl cyanide monomer (a2). (4) The method for producing a polymer according to (3), wherein the monomer (a) further comprises a monomer (a3) ​​copolymerizable with the aromatic vinyl monomer (a1) and the vinyl cyanide monomer (a2). (5) The method for producing a polymer according to (4), wherein the monomer (a3) ​​is an unsaturated carboxylic acid alkyl ester monomer. (6) The method for producing a polymer according to any one of (1) to (5), wherein process (I) predicts the trend of future operating data based on the results of chemical engineering, statistics, or both. (7) The method for producing a polymer according to any one of (1) to (6), wherein process (II) determines the control variables and control amounts to be adjusted based on model predictive control.(8) A method for producing a resin composition, comprising the steps of producing a polymer (A) by a polymer production method described in any one of (1) to (7) above, and a melt-kneading step of melt-kneading the polymer (A) to produce a resin composition, wherein the method includes a step of calculating the physical properties of the final resin composition obtained from the operating data acquired in the step of producing the polymer (A) and the melt-kneading step, and in the step of producing the polymer (A), the step of process (II) determines the operating variables and operating amounts to be adjusted from the present to the future based on the data obtained in the step of process (I) and the step of process (III). (9) The method for producing a resin composition according to (8), wherein the step of process (III) calculates the physical properties of the final resin composition based on a soft sensor. (10) A method for producing the resin composition according to (8) or (9), wherein the physical properties of the resin composition are at least one selected from the group consisting of tensile strength, flexural strength, Izod impact strength, Charpy impact strength, temperature of deflection under load, MFR, YI, and HAZE, measured by a method conforming to JIS, ISO, or ASTM.

[0010] The present invention relates to a polymerization reaction control process in which state variables representing the behavior of a polymerization reaction are controlled by adjusting operational variables that control the polymerization reaction. This process is characterized by predicting the changes in state variables from the present to the future, using the prediction results as indicators to quickly determine and execute the operational variables and amounts to be adjusted from the present to the future, thereby controlling the polymerization reaction. According to the manufacturing method of the present invention, polymers can be efficiently obtained by a small number of operators, and the work efficiency and quality are not affected by the skill level of the operators. Furthermore, since the manufacturing method of the resin composition of the present invention calculates the physical properties of the final resin composition obtained from the operating data, the quality measurement work of the resin composition that was conventionally performed by operators is unnecessary, making it possible to obtain the resin composition more efficiently.

[0011] Figure 1 is a flow sheet showing one embodiment of the method for producing a polymer according to the present invention. Figure 2 is a flow sheet showing one embodiment of the method for producing a resin composition according to the present invention.

[0012] The methods for producing the polymers and resin compositions of the present invention will be described in detail below. However, the present invention is not limited to the embodiments described below and can be modified as needed.

[0013] In this specification, (meth)acrylate means acrylate or methacrylate. Also, in this specification, "mass" is synonymous with "weight."

[0014] (Method for producing polymers) The method for producing polymers according to an embodiment of the present invention (hereinafter also referred to as this embodiment) includes a polymerization step of supplying polymer raw materials containing monomer (a) to a polymerization reactor and causing a polymerization reaction to obtain polymer (A). Here, the polymerization step includes a polymerization reaction control process that controls state variables representing the behavior of the polymerization reaction by adjusting operational variables that control the polymerization reaction, and the operational variables and state variables are continuous or intermittent operating data obtained from measuring instruments and other ancillary equipment attached to the manufacturing facility. The polymerization reaction control process includes a process (I) that predicts the changes in state variables from the present to the future, and a process (II) that determines and executes the operational variables and manipulated amounts to be adjusted from the present to the future based on the data obtained in process (I), and the method for producing polymers according to the present invention controls the polymerization reaction by these processes (I) and (II). That is, the method for producing polymers according to this embodiment focuses on the fact that the changes in state variables from the present to the future can be predicted with high accuracy from operating data, and based on this prediction result, it determines and executes the operational variables and manipulated amounts to be adjusted from the present to the future, thereby efficiently obtaining polymers.

[0015] In the present invention, "state variables" indicate the behavior of the polymerization reaction and are arbitrarily determined as parameters for monitoring the state of the polymerization reaction, taking into account the characteristics of the manufacturing method. Examples include the power of the stirrer installed in the polymerization reactor, the liquid level in the polymerization reactor, and the temperature. "Operational variables" are parameters adjusted to control the behavior of the polymerization reaction, i.e., the state variables, and are arbitrarily determined, taking into account the characteristics of the manufacturing method. Examples of operational variables include the amount of polymerization initiator supplied (polymerization initiator concentration), the amount of chain transfer agent supplied (chain transfer agent concentration), the pressure inside the polymerization reactor, and the residence time. Preferably, the operational variable is at least one selected from the group consisting of the set pressure inside the polymerization reactor, the rate at which polymer (A) is discharged from the polymerization reactor, the set value of the polymerization initiator supply, and the set value of the chain transfer agent supply.

[0016] The polymer (A) produced by the polymer production method of this embodiment is not particularly limited and may contain unreacted substances, oligomers, solvents, etc. Examples of polymer (A) include polyvinyl chloride, polyethylene, polypropylene, AS resin (acrylonitrile-styrene copolymer), MAS resin (methyl methacrylate-acrylonitrile-styrene copolymer), ABS resin (acrylonitrile-butadiene-styrene copolymer), MABS resin (methyl methacrylate-acrylonitrile-butadiene-styrene copolymer), AES resin (acrylonitrile-ethylene propylene-styrene copolymer), ASA resin (acrylonitrile-styrene-methyl acrylate copolymer), PMMA (polymethyl methacrylate), polystyrene, high-impact polystyrene, EVA (ethylene-vinyl acetate copolymer), polyamide, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polylactic acid, etc., with AS resin and MAS resin being particularly preferred.

[0017] The polymerization method for polymer (A) produced by the polymer production method of this embodiment is not particularly limited, and examples include radical polymerization, cationic polymerization, anionic polymerization, coordination polymerization, polycondensation polymerization, polyaddition polymerization, and living polymerization, with radical polymerization being particularly preferred. The polymerization may be continuous polymerization or batch polymerization.

[0018] As shown in Figure 1, the manufacturing apparatus for the polymer manufacturing method of this embodiment comprises a pipe 1 for supplying polymer raw materials containing monomer (a), a polymerization reactor 3 for carrying out a polymerization reaction, and a polymer discharge device 4 for discharging the reactant (polymer (A)) obtained in the polymerization reactor from the polymerization reactor 3. The polymer (A) discharged from the polymerization reactor 3 by the polymer discharge device 4 is sent out through pipe 5. The polymerization reactor 3 is preferably equipped with a stirrer 2 in order to ensure that the polymerization reaction proceeds uniformly within the polymerization reactor. Examples of stirrers 2 include impeller blades and static mixers, with impeller blades being particularly preferred. Examples of impeller blades include paddle blades, turbine blades, propeller blades, bull margin blades, multi-stage blades, anchor blades, maxblend blades, and double helical blades.

[0019] Monomer (a) is appropriately selected depending on the target polymer. Examples of monomer (a) include vinyl monomers, monomers copolymerizable with vinyl monomers, and olefin monomers. These monomers may be used individually or as a mixture of two or more.

[0020] Examples of vinyl monomers include aromatic vinyl monomers (a1) and vinyl cyanide monomers (a2). Examples of aromatic vinyl monomers (a1) include styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, t-butylstyrene, o-ethylstyrene, o-chlorostyrene, o,p-dichlorostyrene, or mixtures of two or more of these, with styrene and α-methylstyrene being particularly preferred. Examples of vinyl cyanide monomers (a2) include acrylonitrile, methacrylonitrile, ethacrylonitrile, or mixtures of two or more of these, with acrylonitrile being particularly preferred. Vinyl monomers may be used individually or in combination of two or more.

[0021] Examples of monomers copolymerizable with vinyl monomers (a3) ​​include unsaturated carboxylic acids such as acrylic acid and methacrylic acid, unsaturated alkyl carboxylic acid esters such as methyl acrylate and methyl methacrylate, unsaturated dicarboxylic acids such as maleic acid, unsaturated dicarboxylic acid anhydrides such as maleic anhydride, N-substituted maleimides such as N-phenylmaleimide, and unsaturated amides such as acrylamide, but unsaturated alkyl carboxylic acid ester monomers are preferred. One monomer copolymerizable with vinyl monomers (a3) ​​may be used alone, or two or more may be used in combination.

[0022] Examples of unsaturated carboxylate alkyl ester monomers include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, 2,3,5-trimethylhexyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, and lauryl (meth) Examples include acrylate, tridecyl (meth)acrylate, 4-ethyl-5-methyloctyl (meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, eicosyl (meth)acrylate, behenyl (meth)acrylate, naphthyl (meth)acrylate, pyrenyl (meth)acrylate, biphenylyl (meth)acrylate, anthryl (meth)acrylate, phenanthryl (meth)acrylate, trityl (meth)acrylate, dicyclopentanyl (meth)acrylate, isobornyl (meth)acrylate, etc., but methyl (meth)acrylate is preferred.

[0023] Examples of olefinic monomers include olefins such as ethylene and propylene; and α-olefins such as 1-butene, isobutene, 1-pentene, 3-methyl-1-butene, 1-hexene, 1-octene, and 1-decene-1 (for example, α-olefins with 2 to 12 carbon atoms). These may be used individually or in combination of two or more.

[0024] The polymer raw material preferably contains a vinyl monomer as monomer (a), and more preferably contains at least one selected from the group consisting of aromatic vinyl monomers (a1) and vinyl cyanide monomers (a2). Furthermore, it is even more preferable to contain at least one selected from the group consisting of aromatic vinyl monomers (a1) and vinyl cyanide monomers (a2), and a monomer (a3) ​​copolymerizable with these vinyl monomers.

[0025] The type and amount of monomer (a) can be adjusted as appropriate according to the target polymer and are arbitrary.

[0026] The polymer raw material may contain monomers other than monomer (a) described above, polymerization initiators, chain transfer agents, solvents, etc.

[0027] Examples of monomers other than monomer (a) include conjugated diene monomers such as butadiene, isoprene, and chloroprene.

[0028] When producing polymer (A) using the polymer production method of this embodiment, it is possible to perform thermal polymerization without using a polymerization initiator, to perform initiator polymerization using a polymerization initiator, or to perform thermal polymerization and initiator polymerization in combination. Peroxides or azo compounds can be used as polymerization initiators.

[0029] Specific examples of peroxides include benzoyl peroxide, cumene hydroperoxide, dicumyl peroxide, diisopropylbenzene hydroperoxide, t-butyl hydroperoxide, t-butylcumyl peroxide, t-butyl peroxyacetate, t-butyl peroxybenzoate, t-butyl peroxyisopropyl carbonate, di-t-butyl peroxide, t-butyl peroctate, 1,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, and t-butylperoxy-2-ethylhexanoate.

[0030] Specific examples of azo compounds include azobisisobutyronitrile, azobis(2,4-dimethylvaleronitrile), 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile, 2-cyano-2-propylazoformamide, 1,1'-azobiscyclohexane-1-carbonitride, azobis(4-methoxy-2,4-dimethylvaleronitrile), dimethyl2,2'-azobisisobutyrate, 1-t-butylazo-1-cyanocyclohexane, 2-t-butylazo-2-cyanobutane, and 2-t-butylazo-2-cyano-4-methoxy-4-methylpentane.

[0031] Furthermore, when producing polymer (A) by the polymer production method of this embodiment, it is preferable to add chain transfer agents such as alkyl mercaptan, carbon tetrachloride, carbon tetrabromide, dimethylacetamide, dimethylformamide, and triethylamine for the purpose of adjusting the degree of polymerization. Examples of alkyl mercaptans used in this embodiment include n-octyl mercaptan, t-dodecyl mercaptan, n-dodecyl mercaptan, n-tetradecyl mercaptan, and n-octadecyl mercaptan, among which n-octyl mercaptan, t-dodecyl mercaptan, and n-dodecyl mercaptan are particularly preferred as chain transfer agents.

[0032] When continuous solution polymerization is selected as the polymerization reaction to obtain polymer (A), a solvent is used in addition to the monomer (a) mentioned above. The solvent used may also contain a saturated amount of water. Examples of solvents include hydrocarbon solvents such as toluene, ethylbenzene, and xylene, and polar solvents such as methyl ethyl ketone, methyl isobutyl ketone, butyl alcohol, and tetrahydrofuran. Among these, polar solvents are preferred, more preferably solvents having a ketone group such as methyl ethyl ketone or methyl isobutyl ketone, and even more preferably methyl ethyl ketone due to the solubility of polymer (A).

[0033] Other polymer raw materials can be used, either one or more of each.

[0034] As shown in Figure 1, the polymer raw material containing monomer (a) is supplied from piping 1 to the polymerization reactor 3, and polymerization is carried out by stirring the polymer raw material with a stirrer 2 to produce the desired polymer (polymer compound). The polymerization reaction can be controlled by adjusting polymerization conditions such as the temperature inside the polymerization reactor, the pressure inside the polymerization reactor, the amount of polymerization initiator supplied (polymerization initiator concentration), the amount of chain transfer agent supplied (chain transfer agent concentration), and the residence time.

[0035] In this embodiment, the polymer raw materials may be supplied to the polymerization reactor continuously or intermittently, and the polymerization method may be bulk polymerization, solution polymerization, emulsion polymerization, or suspension polymerization.

[0036] <Polymerization Reaction Control Process> As described above, polymer (A) is produced by a manufacturing method that includes a polymerization step. In the polymer manufacturing method of this embodiment, the state variables, i.e., the polymerization reaction, are controlled by predicting the changes in state variables from the present to the future (process (I)), and then determining and executing the operational variables and amounts to be adjusted from the present to the future based on this prediction result (process (II)).

[0037] (Process (I)) In Process (I) of the polymer manufacturing method of this embodiment, calculation methods based on chemical engineering, statistics, etc., are used to predict the future changes in state variables from the changes in instrumental variables and state variables from the past to the present. That is, in Process (I), the changes in future operating data are predicted based on the calculation results of chemical engineering, statistics, or both. The period from the past to the present and from the present to the future is appropriately determined according to empirical rules and the manufacturing time of the target polymer (manufacturing time based on the reaction rate of the polymerization reaction, etc.).

[0038] Examples of calculation methods based on chemical engineering include mass balance and heat balance, while examples of calculation methods based on statistics include linear regression analysis, logistic regression analysis, decision tree analysis, and neural networks. These calculation methods may be used individually or in combination of two or more. Furthermore, these calculation methods can be performed using publicly known programs, such as AVEVA PRO / II Simulation (manufactured by AVEVA Corporation).

[0039] (Process (II)) In process (II) of the polymer manufacturing method of this embodiment, the control variables and control amounts to be adjusted from the present to the future are determined based on the data obtained in process (I). Then, the control amounts are adjusted by changing the output values ​​of the automatic valves and control valves attached to the manufacturing equipment. In this embodiment, it is preferable to utilize model predictive control as a method for determining the control variables and control amounts to be adjusted from the present to the future.

[0040] Model predictive control is a method that calculates the future response of the control output value (state variable) based on changes in the control input value (operated variable), and determines the control input value based on this calculation result. In model predictive control, first, the future response of the control output value is calculated using a predictive model of the controlled object (Step 1). Next, the control input value is determined by solving an optimization problem so that the difference between the future response of the control output value and a predetermined target value is minimized over a period from the present to the future (Step 2). Then, by repeating Step 1 and Step 2, the control output value is brought closer to the target value and controlled. Here, the period from the present to the future is the calculation period for the future response, and is arbitrarily set considering the residence time and polymerization reaction rate in the polymerization reactor. Model predictive control can be performed using known programs, such as SORTiA-MPC (manufactured by Azbil Corporation).

[0041] In this embodiment, the polymer manufacturing method controls the state variables in the polymerization step using a polymerization reaction control process that includes the above processes (I) and (II), thereby reducing variations in quality and enabling efficient polymer production.

[0042] (Method for Manufacturing a Resin Composition) The present invention also provides a method for manufacturing a resin composition, in which a polymer (A) is obtained by a manufacturing method including a polymerization step, and then a resin composition is manufactured by removing unreacted substances, solvents, etc. That is, the method for manufacturing a resin composition according to an embodiment of the present invention includes a step of manufacturing a polymer (A) by the polymer manufacturing method described above, and a melt-kneading step of manufacturing a resin composition by melt-kneading the obtained polymer (A). The method for manufacturing a resin composition according to this embodiment includes a process (III) for calculating the physical properties of the final resin composition obtained from the operating data acquired in the step of manufacturing the polymer (A) and the melt-kneading step, and in the step of manufacturing the polymer (A), based on the data obtained in process (I) and process (III), process (II) determines the operating variables and operating amounts that should be adjusted from the present to the future.

[0043] In the melt-kneading process, a polymer (B) different from polymer (A) may be mixed with polymer (A) to produce a resin composition.

[0044] The polymer (B) is not particularly limited. For example, polyvinyl chloride, polyethylene, polypropylene, AS resin (acrylonitrile-styrene copolymer), MAS resin (methyl methacrylate-acrylonitrile-styrene copolymer), ABS resin (acrylonitrile-butadiene-styrene copolymer), MABS resin (methyl methacrylate-acrylonitrile-butadiene-styrene copolymer), AES resin (acrylonitrile-ethylene propylene-styrene copolymer), ASA resin (acrylonitrile-styrene-methyl acrylate copolymer), PMMA (polymethyl methacrylate), polystyrene, impact-resistant polystyrene, EVA (ethylene-vinyl acetate copolymer), polyamide, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polylactic acid, etc. can be mentioned.

[0045] Among them, the polymer (B) is preferably a graft copolymer (B1) obtained by graft-polymerizing a monomer (b) containing an aromatic vinyl monomer (b1) and a vinyl cyanide monomer (b2) in the presence of a rubber-like polymer.

[0046] The rubber-like polymer constituting the graft copolymer (B1) is a diene rubber, an acrylic rubber, an ethylene rubber, etc. Specific examples include polybutadiene, poly(butadiene-styrene), poly(butadiene-acrylonitrile), polyisoprene, poly(butadiene-methyl acrylate), poly(butadiene-methyl methacrylate), poly(butadiene-ethyl acrylate), ethylene-propylene rubber, ethylene-propylene-diene rubber, poly(ethylene-isobutylene), poly(ethylene-methyl acrylate), etc. These rubber-like polymers are used as one kind or a mixture of two or more kinds. Among these rubber-like polymers, diene rubbers are preferably used, and among the diene rubbers, polybutadiene, poly(butadiene-styrene), poly(butadiene-acrylonitrile), and ethylene-propylene rubber are particularly preferably used.

[0047] As the aromatic vinyl monomer (b1), styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, t-butylstyrene, o-ethylstyrene, o-chlorostyrene, o,p-dichlorostyrene, or a mixture of two or more thereof can be mentioned. In particular, styrene and α-methylstyrene are preferably used. As the vinyl cyanide monomer (b2), acrylonitrile, methacrylonitrile, ethacrylonitrile, or a mixture of two or more thereof can be mentioned. In particular, acrylonitrile is preferably used. The aromatic vinyl monomer (b1) and the vinyl cyanide monomer (b2) may each be used alone or in combination of two or more.

[0048] Further, the monomer (b) may be composed of the aromatic vinyl monomer (b1) and the vinyl cyanide monomer (b2), or may contain the aromatic vinyl monomer (b1), the vinyl cyanide monomer (b2), and a monomer (b3) copolymerizable with these.

[0049] As the monomer (b3), for example, unsaturated carboxylic acids such as acrylic acid and methacrylic acid, alkyl esters of unsaturated carboxylic acids such as methyl acrylate and methyl methacrylate, unsaturated dicarboxylic acids such as maleic acid, unsaturated dicarboxylic acid anhydrides such as maleic anhydride, N-substituted maleimides such as N-phenylmaleimide, and unsaturated amides such as acrylamide can be mentioned. Among them, alkyl ester monomers of unsaturated carboxylic acids are preferred. Each of the monomers (b3) may be used alone or in combination of two or more.

[0050] Examples of unsaturated carboxylate alkyl ester monomers include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, 2,3,5-trimethylhexyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, and lauryl (meth) Examples include acrylate, tridecyl (meth)acrylate, 4-ethyl-5-methyloctyl (meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, eicosyl (meth)acrylate, behenyl (meth)acrylate, naphthyl (meth)acrylate, pyrenyl (meth)acrylate, biphenylyl (meth)acrylate, anthryl (meth)acrylate, phenanthryl (meth)acrylate, trityl (meth)acrylate, dicyclopentanyl (meth)acrylate, isobornyl (meth)acrylate, etc., but methyl (meth)acrylate is preferred.

[0051] Furthermore, depending on the properties required for the resin composition, additional steps may be taken to add various stabilizers such as antioxidants (hindered phenols, sulfur-containing organic compounds, phosphorus-containing organic compounds, etc.), heat stabilizers (phenols, acrylates, etc.), UV absorbers (benzotriazoles, benzophenones, salicylates, etc.), light stabilizers (organicickels, hindered amines, etc.), lubricants (metal salts of higher fatty acids, higher fatty acid amides, etc.), plasticizers (phthalates, phosphate esters, etc.), halogen-containing compounds (polybrominated diphenyl ethers, tetrabromobisphenol-A, brominated epoxy oligomers, brominated polycarbonate oligomers, etc.), phosphorus compounds, flame retardants / flame retardant additives (antimony trioxide, etc.), antistatic agents, carbon black, titanium dioxide, pigments and dyes, and liquids such as water, silicone oil, and liquid paraffin. Additionally, additional steps may be taken to add reinforcing agents and fillers such as glass fibers, glass flakes, glass beads, carbon fibers, and metal fibers. There are no particular restrictions on the method of adding these additives, and they can be added continuously together with polymer (B).

[0052] As shown in Figure 2, the manufacturing apparatus for carrying out the resin composition manufacturing method of this embodiment includes a pipe 6 for supplying polymer raw materials containing monomer (a), a polymerization reactor 8 for performing a polymerization reaction, a second extruder (polymer addition section) 13 for supplying polymer (B), a first extruder 11 for melt-kneading polymer (A) and polymer (B) obtained in the polymerization reactor 8 to produce a resin composition, and a granulator 14 for granulating the resin composition. The polymer (A) obtained in the polymerization reactor 8 is discharged from the polymerization reactor 8 by a polymer discharge device 9 and sent to the first extruder 11 by pipe 10. The first extruder 11 is provided with a vent 12 upstream of the connection part to the second extruder 13, allowing unreacted material, oligomers, solvents, etc. to be discharged from the vent 12. Furthermore, the polymerization reactor 8 is preferably equipped with a stirrer 7 in order to uniformly carry out the polymerization reaction within the polymerization reactor, and the above-mentioned stirrer 7 is an example of such a stirrer 7, and other preferred stirrers are also similar.

[0053] <Polymerization Reaction Control Process> The method for producing the resin composition of this embodiment includes a process (III) for calculating the physical properties of the final resin composition from the operating data obtained in the process of producing the polymer (A) and the melt-kneading process. In the method for producing the resin composition of this embodiment, the state variables, i.e., the polymerization reaction, are controlled by predicting the changes in state variables from the present to the future (process (I)), calculating the physical properties of the final resin composition from the operating data (process (III)), and determining and executing the operational variables and amounts to be adjusted from the present to the future based on the data obtained in process (I) and process (III) (process (II)).

[0054] (Process (III)) In process (III) of the resin composition manufacturing method of this embodiment, the physical properties of the final resin composition obtained are calculated from the operating data using a calculation method based on statistics or the like. The operating data obtained in the process of manufacturing polymer (A) consists of operational variables and state variables as described above, and is continuous or intermittent operating data obtained from measuring instruments and other ancillary equipment attached to the manufacturing equipment. Similarly, the operating data obtained in the melt-kneading process consists of continuous or intermittent operating data obtained from measuring instruments and other ancillary equipment attached to the manufacturing equipment, and includes, for example, extruder power, extruder screw rotation speed, extruder barrel temperature, extruder outlet pressure, polymer (B) flow rate, and additive flow rate.

[0055] As a method for calculating the physical properties of the resin composition ultimately obtained from these operating data, it is preferable to utilize soft sensors. A soft sensor is a device that mathematically calculates the relationship between measured values ​​of variables that can be measured relatively easily and a target state variable. In this embodiment, it is preferable to utilize soft sensors and use a statistical model selected and used with the operating data obtained in the polymer (A) manufacturing process and the melt-kneading process to create a formula for predicting the physical properties of the resin composition.

[0056] The statistical model described above is not particularly limited, but any statistical model commonly used in soft sensor construction, such as linear or nonlinear models, can be used. However, linear models may suffer from overfitting, resulting in lower accuracy, so nonlinear models are preferred. When using soft sensors, as described above, the relationship between the measured values ​​of the measured variables and the target state variables is learned from past data, and an estimation formula is created in advance. Then, the target state variables are calculated online from the measured values ​​of the variables measured online and the estimation formula. Overfitting occurs when the estimation formula created from this past data is applied to the unknown online data that should actually be predicted, and the state variables predicted from the estimation formula do not match the actual state variables. Therefore, in this embodiment, a nonlinear model is preferred as a statistical model with good accuracy.

[0057] The physical properties of the resin composition calculated by process (III) include, for example, tensile strength, flexural strength, Izod impact strength, Charpy impact strength, temperature of deflection under load, MFR (Melt Flow Rate), YI (yellowness), and haze, measured by a method conforming to JIS, ISO, or ASTM. At least one of these properties should be selected from the group. In particular, it is preferable to calculate MFR, which is the most important physical property that serves as a measure of the moldability of the resin composition and the rigidity of the product after molding.

[0058] The following describes in more detail the method for producing the polymer and the resin composition of the present invention, with reference to examples, but these examples do not limit the present invention in any way.

[0059] (Reference Example) Method for producing graft copolymer (B1) (emulsion polymerization) 50 parts by mass (on a solids basis) of polybutadiene latex (rubber particle size 0.3 μm, gel content 85%), 180 parts by mass of pure water, 0.4 parts by mass of sodium formaldehyde sulfoxylate, 0.1 parts by mass of sodium ethylenediaminetetraacetate, 0.01 parts by mass of ferrous sulfate, and 0.1 parts by mass of sodium phosphate were charged into a reaction vessel. After purging with nitrogen, the temperature was controlled to 65°C, and under stirring, a mixture of 11.5 parts by mass of styrene, 4.0 parts by mass of acrylonitrile, 34.5 parts by mass of methyl methacrylate, and 0.3 parts by mass of n-dodecyl mercaptan was continuously added dropwise over 4 hours. Simultaneously, a mixture of 0.25 parts by mass of cumene hydroperoxide, 2.5 parts by mass of sodium oleate (an emulsifier), and 25 parts by mass of pure water was continuously added dropwise over 5 hours. After the dropwise addition was completed, the mixture was held for another hour to finish polymerization. The latex-like product after polymerization was poured into 2000 parts by mass of 95°C water with 1.0 part by mass of sulfuric acid while stirring to allow it to coagulate. Then, it was neutralized with alkali, washed, centrifuged, and dried to prepare a powder-like graft copolymer (B1).

[0060] (Example) The manufacturing apparatus used to carry out the method for producing the resin composition is shown in Figure 2. Polymer raw materials consisting of 72 parts by mass of methyl methacrylate (MMA), 24 parts by mass of styrene (ST), 4 parts by mass of acrylonitrile (AN), 0.014 parts by mass of 1,1-di(t-butylperoxy)cyclohexane (polymerization initiator), and 0.215 parts by mass of n-octyl mercaptan (chain transfer agent) were continuously supplied to a polymerization reactor 8 (capacity 20 L) equipped with a helical ribbon blade as the stirring blade 7, and continuous polymerization was carried out. At this time, the liquid volume in the polymerization reactor 8 and the supply rate of the polymer raw materials were set so that the residence time in the polymerization reactor 8 was 4 hours, and polymer (A) containing 30 parts by mass of unreacted material relative to polymer (A) was obtained. Polymer (A) was fed to a first extruder 11 equipped with a vent 12, and unreacted material etc. was removed from the vent 12. Next, the graft copolymer (B1) prepared in the reference example was supplied from the second extruder 13, which was connected to the first extruder 11 midway (downstream of the vent 12), at an addition ratio of 30 parts by mass per 100 parts by mass of polymer (A). After mixing polymer (A) and graft copolymer (B1) downstream of the first extruder 11, the molten resin composition was discharged in strand form from the outlet of the first extruder 11 and granulated by a pelletizer acting as a granulator 14 to obtain resin composition pellets.

[0061] In the polymerization process for producing polymer (A), the polymerization reaction control process automatically adjusts the set pressure in the polymerization reactor, the rate at which polymer (A) is discharged from the polymerization reactor, the set value for the polymerization initiator supply, and the set value for the chain transfer agent supply by: (I) predicting the change in state variables from the present to 4 hours later based on the changes in operational variables and state variables from 4 hours ago to the present; (II) determining the operational variables and amounts to be adjusted from the present to 4 hours later; and (III) calculating the MFR of the final resin composition from the operating data.

[0062] In process (I), based on calculations of mass balance and heat balance, the changes in operational and state variables from four hours prior to the present were used to predict the changes in state variables four hours later, with a 5-minute period. The state variables predicted by process (I) were the power of the stirrer installed in the polymerization reactor, the liquid level in the polymerization reactor, and the temperature.

[0063] In process (III), a regression equation was created to predict the MFR of the resin composition from operating data using a soft sensor, and the MFR of the resin composition was predicted at 5-minute intervals based on this regression equation.

[0064] In process (II), based on the data obtained in processes (I) and (III), the control variables and amounts to be adjusted four hours from the present were determined in a 5-minute cycle. The polymerization reaction was then automatically controlled by automatically changing the control settings of the control variables in the Distributed Control System (DCS). The control variables used were the set pressure in the polymerization reactor, the rate at which polymer (A) was discharged from the polymerization reactor, the set value for the polymerization initiator supply, and the set value for the chain transfer agent supply.

[0065] As a result of continuing operation for one day under the above conditions, we were able to efficiently obtain the resin composition without requiring skilled operators to monitor state variables and adjust control variables, or operators to evaluate the quality of the resin composition.

[0066] Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible without departing from the intent and scope of the invention. This application is based on Japanese Patent Application No. 2024-168811, filed on September 27, 2024, which is incorporated herein by reference in its entirety.

[0067] 1, 5, 6, 10: Piping 2, 7: Agitator 3, 8: Polymer reactor 4, 9: Polymer discharge device (gear pump) 11: First extruder 12: Vent 13: Second extruder (polymer addition section) 14: Granulator (pelletizer)

Claims

1. A method for producing a polymer, comprising a polymerization step of supplying a polymer raw material containing monomer (a) to a polymerization reactor and causing a polymerization reaction to obtain a polymer (A), wherein the polymerization step includes a polymerization reaction control process that controls state variables representing the behavior of the polymerization reaction by adjusting operational variables that control the polymerization reaction, the operational variables and state variables being continuous or intermittent operating data obtained from measuring instruments and other ancillary equipment attached to the manufacturing facility, and the polymerization reaction control process comprising a process (I) of predicting the changes in state variables from the present to the future, and a process (II) of determining and executing operational variables and manipulated amounts to be adjusted from the present to the future based on the data obtained in process (I), the method for producing a polymer.

2. The method for producing a polymer according to claim 1, wherein the operating variable is at least one selected from the group consisting of the set pressure in the polymerization reactor, the rate at which the polymer (A) is discharged from the polymerization reactor, the set value for the polymerization initiator supply, and the set value for the chain transfer agent supply.

3. The method for producing a polymer according to claim 1, wherein the monomer (a) comprises at least one selected from the group consisting of aromatic vinyl monomers (a1) and vinyl cyanide monomers (a2).

4. The method for producing a polymer according to claim 3, wherein the monomer (a) further comprises a monomer (a3) ​​copolymerizable with an aromatic vinyl monomer (a1) and a vinyl cyanide monomer (a2).

5. The method for producing a polymer according to claim 4, wherein the monomer (a3) ​​is an unsaturated carboxylic acid alkyl ester monomer.

6. The method for producing a polymer according to claim 1, wherein process (I) predicts the trend of future operating data based on the results of chemical engineering, statistics, or both.

7. The method for producing a polymer according to claim 1, wherein process (II) determines the control variables and amounts to be adjusted based on model predictive control.

8. A method for producing a resin composition, comprising the steps of: producing a polymer (A) by a polymer production method described in any one of claims 1 to 7; and a melt-kneading step of producing a resin composition by melt-kneading the polymer (A), the method comprising a step (III) of calculating the physical properties of the final resin composition obtained from the operating data acquired in the step of producing the polymer (A) and the melt-kneading step, wherein in the step of producing the polymer (A), the step (II) determines the operating variables and operating amounts to be adjusted from the present to the future based on the data obtained in the step (I) and the step (III).

9. The method for producing a resin composition according to claim 8, wherein process (III) calculates the physical properties of the resin composition finally obtained based on a soft sensor.

10. A method for producing the resin composition according to claim 8, wherein the physical properties of the resin composition are at least one selected from the group consisting of tensile strength, flexural strength, Izod impact strength, Charpy impact strength, temperature of deflection under load, MFR, YI, and HAZE, measured by a method conforming to JIS, ISO, or ASTM.

Images