KR20200096126A - Method of producing ethylene-carboxylic acid compolymer - Google Patents

Abstract

In a method for producing an ethylene-carboxylic acid copolymer of embodiments of the present invention, a carboxylic acid monomer and a polar co-solvent are separately introduced into a mixing portion or stored alongside each other in a supply portion to form a mixture. The mixture and ethylene are injected into a reactor and copolymerized. The reaction kinetic properties of the carboxylic acid monomer and the polar co-solvent can be controlled to inhibit byproduct formation.

Description

Method for producing an ethylene-carboxylic acid copolymer TECHNICAL FIELD [METHOD OF PRODUCING ETHYLENE-CARBOXYLIC ACID COMPOLYMER}

The present invention relates to a method for producing an ethylene-carboxylic acid copolymer.

For example, ethylene-carboxylic acid copolymers such as ethylene-acrylic acid copolymers are used in various applications such as sealing materials, adhesives, packing materials, and optical films.

The ethylene-carboxylic acid copolymer may be prepared by polymerizing ethylene and a carboxylic acid-based compound (eg, acrylic acid, methacrylic acid, etc.) as a comonomer through a continuous reactor.

Carboxylic acid-based compounds have higher self-reactivity than ethylene, and can be self-polymerized when exposed to high temperatures during supply through flow paths, pumps, compressors, and the like. Accordingly, clogging of the flow path or the like may cause damage to the polymerization facility. In order to prevent such self-polymerization, crystallization of a carboxylic acid-based compound may occur when the operating temperature of the equipment is lowered.

When supplying a carboxylic acid-based compound, a co-solvent may be used together to prevent crystallization and suppress fouling in a facility. However, when using a polar solvent as a co-solvent, a by-product may be generated by reacting with a carboxylic acid-based compound.

In addition, for example, when a continuous process is performed under severe polymerization conditions of high temperature and high pressure, detailed component analysis and reaction analysis of by-products in the flow path may be substantially difficult.

Therefore, it is necessary to control the polymerization process and process parameters that can suppress additional by-products while preventing self-polymerization of the carboxylic acid-based compound.

For example, U.S. Patent Publication No. 6,852,792 discloses an aqueous dispersion for sealing comprising an ethylene-acrylic acid copolymer, but does not recognize the above-described requirements for designing a polymerization process.

US Patent Publication No. 6,852,792

One object of the present invention is to provide a method for producing an ethylene-carboxylic acid copolymer having improved process reliability and polymerization efficiency.

In a method for preparing an ethylene-carboxylic acid copolymer according to exemplary embodiments, a mixture of a carboxylic acid monomer and an organic solvent-based polar cosolvent is formed. The mixture and ethylene are injected into a reactor for copolymerization. In forming the mixture of the carboxylic acid monomer and the organic solvent-based polar cosolvent, the Reaction Progress Index (RPI) defined by the following Equation 1 is adjusted to a range of 1.5 to 1.3×10 ⁷ sec·K. By controlling the amount of side reaction products of the carboxylic acid monomer and the polar co-solvent.

[Equation 1]

와

는 카르복실산 단량체와 극성 공용매가 혼합되어 도입되는 유로에서의 각각 극성 공용매 및 카르복실산 단량체의 초기 몰 농도이고, t는 상기 카르복실산 단량체 및 상기 극성 공용매의 접촉시간을 나타내며, T는 상기 카르복실산 단량체 및 상기 극성 공용매의 에틸렌과 반응전 접촉 평균 온도임).(Equation 1

Wow

Is the initial molar concentration of the polar co-solvent and the carboxylic acid monomer in the flow path into which the carboxylic acid monomer and the polar co-solvent are mixed and introduced, t represents the contact time of the carboxylic acid monomer and the polar co-solvent, T Is the average contact temperature before reaction with ethylene of the carboxylic acid monomer and the polar cosolvent).

In some embodiments, the reaction progression index may range from 14.9 to 1.3×10 ⁵ sec·K.

In some embodiments, the mixture can be discharged.

In some embodiments, the discharge pressure of the mixture may be greater than the mixing pressure of the carboxylic acid monomer and the polar co-solvent.

In some embodiments, the discharge pressure may be greater than the pressure in the reactor.

In some embodiments, the mixture may be formed by introducing each of the carboxylic acid monomer and the polar co-solvent into the mixing unit. The mixture may be moved from the mixing unit to the discharge unit through a transfer passage, and the mixture may be discharged from the discharge unit through a discharge passage.

In some embodiments, the temperature of the mixture is above the crystallization temperature of the carboxylic acid monomer, and may be maintained below the self-polymerization temperature of the carboxylic acid monomer.

In some embodiments, the mixture can be contacted with ethylene before being injected into the reactor.

In some embodiments, a reaction inhibitor between the carboxylic acid monomer and the polar co-solvent may be injected into the mixture.

In some embodiments, the reaction inhibitor may include an amine-based compound.

In some embodiments, a chain transfer agent may be injected into the mixture through the shear passage of the reactor.

In some embodiments, the chain transfer agent may include a non-polar organic compound.

In some embodiments, the chain transfer agent may include methyl ethyl ketone or isobutane.

In some embodiments, Equation 2 below may be satisfied.

[Equation 2]

및

는 각각 상기 반응기의 상기 전단 유로에서의 상기 극성 공용매 및 상기 사슬 전달제의 몰 농도이고,(In formula 2,

And

Is the molar concentration of the polar cosolvent and the chain transfer agent in the shear flow path of the reactor, respectively,

와

는 200℃에서의 상기 극성 공용매 및 상기 사슬 전달제의 에틸렌에 대한 사슬 전달 계수(Cs)임).

Wow

Is the chain transfer coefficient (Cs) for ethylene of the polar cosolvent and the chain transfer agent at 200°C).

In some embodiments, the carboxylic acid monomer includes acrylic acid, and the polar co-solvent may include ethanol.

In the method for preparing an ethylene-carboxylic acid copolymer according to exemplary embodiments, a polar co-solvent may be used as a carrier fluid for the carboxylic acid monomer. The crystallization temperature of the mixture of polar co-solvent and carboxylic acid monomer can be lower than the crystallization temperature of pure carboxylic acid monomer. Accordingly, it is possible to prevent a decrease in process yield or process efficiency due to self-polymerization due to crystallization or crystallization.

According to exemplary embodiments, side reactions between the carboxylic acid monomer and the polar co-solvent can be suppressed while appropriately controlling the reactivity ability by adjusting the parameters of the carboxylic acid monomer and the polar co-solvent. Therefore, it is possible to prevent side reaction products generated from carboxylic acid monomers to prevent deterioration of physical properties of the polymer product, and to prevent the residual of side reaction products in the product. In addition, the copolymerization yield, conversion rate, and molecular weight and molecular weight distribution of the product can be appropriately controlled.

According to exemplary embodiments, for example, side reaction products can be effectively suppressed without reducing process efficiency by adjusting process conditions without adding a separate analysis facility for identifying side reaction products in a high temperature and high pressure flow path.

1 is a schematic process flow diagram illustrating a method of manufacturing an ethylene-carboxylic acid copolymer according to exemplary embodiments.
2 is a schematic process flow diagram illustrating a method of manufacturing an ethylene-carboxylic acid copolymer according to some exemplary embodiments.
3 to 11 are graphs showing the amount of ethyl acrylate generated over time.

Embodiments of the present invention provides a method for preparing an ethylene-carboxylic acid copolymer capable of inducing copolymerization with ethylene by supplying a carboxylic acid monomer together with a polar co-solvent, and suppressing side reactions caused by the polar co-solvent.

Hereinafter, preferred embodiments of the present invention are presented, but these embodiments are merely illustrative of the present invention and do not limit the scope of the appended claims, and various examples of the embodiments within the scope and technical scope of the present invention. It is obvious to those skilled in the art that changes and modifications are possible, and it is natural that such modifications and modifications fall within the scope of the appended claims.

1 is a schematic process flow diagram for explaining a method for preparing an ethylene-carboxylic acid copolymer according to exemplary embodiments.

Referring to FIG. 1, a carboxylic acid monomer and a polar co-solvent may be supplied to the introduction unit. For example, a carboxylic acid monomer and a polar co-solvent may be supplied to the mixing unit 30 from the carboxylic acid monomer supply unit 10 and the co-solvent supply unit 20, respectively.

The carboxylic acid monomer may include an unsaturated carboxylic acid capable of a chain polymerization reaction. According to exemplary embodiments, (meth)acrylic acid or an ester thereof (eg, (meth)acrylate) may be used as the carboxylic acid monomer. In the present application, (meth)acrylic acid is used as a term encompassing methacrylic acid and acrylic acid.

The polar co-solvent is mixed with the carboxylic acid monomer and transferred to the reactor, and crystallization and self-polymerization of the carboxylic acid monomer can be suppressed.

For example, the crystallization temperature of the polar co-solvent and carboxylic acid monomer mixture can be lower than the crystallization temperature of the pure carboxylic acid monomer. Accordingly, an allowable range of process temperature that can prevent crystallization can be increased. Therefore, it is possible to lower the operating temperature of the equipment without causing crystallization, thereby reducing the self-polymerization of the carboxylic acid monomer.

According to exemplary embodiments, a polar organic solvent such as an alcohol-based solvent, an ether-based solvent, or a ketone-based solvent may be used as the polar co-solvent. For example, ethanol, methanol, propanol, butanol, and the like may be used as the alcohol-based solvent.

In one preferred embodiment, ethanol, acetone and/or ethyl acetate can be used as the polar co-solvent.

According to exemplary embodiments, water may be excluded from the polar co-solvent. When water is used as a polar co-solvent, it is possible to accelerate the polymerization of the carboxylic acid monomer itself. Accordingly, according to embodiments of the present invention, the crystallization temperature can be reduced without promoting self-polymerization by using the above-described organic solvent-based polar cosolvent.

However, when using a polar co-solvent, a by-product may be generated by reacting with a carboxylic acid monomer. For example, when acrylic acid is used as the carboxylic acid monomer and ethanol is used as the polar co-solvent, ethyl acrylate and water by esterification may be produced as by-products.

In addition, when acrylic acid is used as the carboxylic acid monomer and ethyl acetate is used as the polar co-solvent, ethyl acrylate may be produced as a by-product by trans-esterification.

Since ethyl acrylate is a polymerizable material, it is possible to reduce the content of acrylic acid in the chain when preparing the ethyl-acrylic acid copolymer (EAA) copolymer. In addition, when ethyl acrylate participates in polymerization instead of acrylic acid in the chain, the adhesive strength of the resulting copolymer product may be reduced, and due to its bulky properties, crystal formation of the polymer may be inhibited and the melting point may be lowered. The low melting point may cause a blocking phenomenon in which pellet-type polymer products stick together.

Ethyl acrylate may react with water and release ethanol by hydrolysis when exposed to high temperatures. Therefore, when it is included as a by-product in the copolymer product, it is possible to cause residues such as bubbles and bubbles on the inside or the surface of the processed product.

In addition, ethyl acrylate may cause odor even in a small amount as an off-flavor material, and when it is contained in a large amount as a by-product, it may be difficult to be used for a purpose such as food packaging. Accordingly, when the ethylene-carboxylic acid copolymer is used as a food packaging material, the residual content of ethyl acrylate in the product is regulated to less than 6 ppm according to the EU food contact regulations.

In addition, in order to secure the possibility of controlling the side reaction product in advance, the case where the side reaction product remains at 6 ppm in the final product is assumed to be calculated using the plant process simulation model, and the actual side reaction product is, for example, 600 ppm in the discharge unit 40 It is necessary to control to the following level.

In addition, when ethyl acrylate is generated by an ester reaction, water is also generated, so that dimerization of the carboxylic acid monomer and self polymerization may be accelerated by water as described above.

In order to suppress or reduce side effects due to side reactions due to the above-described polar co-solvent input, according to exemplary embodiments, as described later, for example, a mixing unit 30 and a discharge unit 40 are included in the car. The mixing and transport properties of the carboxylic acid monomer and the polar co-solvent in the flow path where the carboxylic acid monomer and the polar co-solvent are transported together can be controlled.

In the ethylene-carboxylic acid copolymer manufacturing process, it is not easy to predict the degree of occurrence of side reaction products due to co-injection through pilot/laboratory equipment. In fact, when the side reaction product evaluation according to the introduction of ethanol was conducted through a pilot/laboratory test for preparing an ethylene-carboxylic acid copolymer, the residual amount of side reaction products in the product was not detectable. However, it was confirmed that ethyl acrylate in the final product was detected at a significant level as a result of injecting the same level of molar ratio of ethanol as a co-solvent into the actual polymerization process.

Therefore, it is necessary to control and design process variables to suppress side reaction products without separate analysis equipment and reaction analysis for analysis results.

[Equation 1]

와

는 카르복실산 단량체와 극성 공용매가 혼합되어 도입되는 유로 혹은 저장부에서의 각각 카르복실산 단량체 및 극성 공용매의 초기 몰농도를 나타낸다. In Equation 1

Wow

Denotes the initial molar concentrations of the carboxylic acid monomer and the polar co-solvent, respectively, in the flow path or the storage unit into which the carboxylic acid monomer and the polar co-solvent are mixed and introduced.

t represents the contact time of the carboxylic acid monomer and the polar co-solvent. For example, t may refer to the time until the carboxylic acid monomer and the polar co-solvent are introduced into the mixing unit 30 and then discharged from the discharge unit 40 to meet the ethylene stream 55.

T can represent the contact average temperature of the carboxylic acid monomer and the polar co-solvent. For example, T is the initial temperature when the carboxylic acid monomer and the polar co-solvent are mixed in the mixing unit 30 and the average temperature of the temperature discharged from the discharge unit 40 and heated by pressurization before meeting the ethylene stream. Can be represented. For example, T is the arithmetic mean of the temperature in the mixing unit 30 and the temperature in the discharge passage 45, or the temperature in the storage tank 65 (see FIG. 2) and the temperature in the discharge passage 80 May refer to the arithmetic mean of.

는 극성 공용매 사용에 의한 부반응 속도에 관련된 인자일 수 있다. 예를 들면, T 및

의 각각의 값이 커지면 에스테르화 반응이 가속될 수 있다. t는 카르복실산 단량체 및 극성 공용매의 부반응이 발생할 수 있는 반응 시간과 관련된 인자일 수 있다.T and

May be a factor related to the side reaction rate due to the use of a polar cosolvent. For example, T and

The esterification reaction may be accelerated when the value of each is increased. t may be a factor related to the reaction time at which a side reaction of the carboxylic acid monomer and the polar co-solvent can occur.

According to exemplary embodiments, the RPI may be adjusted in the range of 1.5 to 1.3×10 ⁷ sec·K. When the value of RPI is less than 1.5 sec·K, the effect of reducing the crystallization temperature by the polar cosolvent may not be sufficiently implemented. When the RPI exceeds 1.3×10 ⁷ sec·K, the esterification reaction proceeds excessively, so that the above-described side effects may occur, and may not be implemented as a commercial product in excess of the regulatory range for side reaction products.

In one preferred embodiment, the RPI value can be adjusted in the range of 14.9 to 1.3×10 ⁵ sec·K.

, t 및 T 각각은 상술한 RPI 범위를 만족하도록 조절되며, 특정 범위로 제한되지 않을 수 있다.

, t and T each are adjusted to satisfy the above-described RPI range, it may not be limited to a specific range.

As described above, as described in Equation 1, the RPI, which combines the process factor affecting the reaction rate and the process time at which the reaction can proceed at the reaction rate, is used as a process control variable in the process of using various polar cosolvents. I can. Accordingly, comprehensive side reaction control can be implemented without installing a separate analysis facility for suppressing side reactions of the carboxylic acid monomer and without analyzing the reactions to the analysis results.

In addition, the amount of side reaction products at a desired level can be easily controlled through RPI regulation. For example, as described with reference to FIGS. 3 to 11, the relationship between the RPI and the side reaction product (eg, ethyl acrylate) may substantially satisfy linear. Therefore, the amount of side reaction products can be easily finely adjusted with high reliability by adjusting the RPI value.

Referring to FIG. 1 again, the carboxylic acid monomer and the polar co-solvent are separately separated from the carboxylic acid monomer supply unit 10 and the co-solvent supply unit 20, and may be separately supplied to the mixing unit 30.

For example, the carboxylic acid monomer and the polar cosolvent may individually enter the mixing unit 30 through the first flow path 15 and the second flow path 25, respectively. Therefore, it is possible to suppress the esterification reaction by reducing the contact time of the carboxylic acid monomer and the polar co-solvent.

In some embodiments, one or more additives such as a polymerization initiator, a reaction inhibitor, and an antioxidant may be supplied to the mixing unit 30 or the storage tank 65 together.

The polymerization initiator may use initiators known in the polymer polymerization field. For example, a peroxide or peroxy-based compound, an azobis-based compound, or the like can be used as the polymerization initiator.

Reaction inhibitors may further be included to inhibit side reactions of the carboxylic acid monomer and polar co-solvent. For example, a reaction inhibitor may inhibit ester production through a competitive reaction with alcohol.

In some embodiments, an amine-based compound may be used as a reaction inhibitor. Examples of the amine-based compound include an alkyl amine such as trimethyl amine.

In some embodiments, the input molar ratio of the reaction inhibitor to the carboxylic acid monomer may be 10 ^-6 to 10 ^-3 . Within this range, esterification can be sufficiently suppressed without lowering the polymerization reaction efficiency.

The carboxylic acid monomer and the polar co-solvent mixed through the mixing unit 30 may be discharged for copolymerization with ethylene through the discharge channel 45 by moving to the discharge unit 40 through the transfer channel 35.

The discharge part 40 may include discharge equipment, such as a pump and a compressor.

According to exemplary embodiments, the temperature at the mixing portion 30 and the discharge portion 40 (for example, mixing temperature and discharge temperature) is higher than the crystallization temperature of the carboxylic acid monomer and self polymerization of the carboxylic acid is It can be lower than the temperature that occurs.

For example, the temperature in the mixing portion 30 and the discharge portion 40 can be adjusted within a range of 20 to 100°C, respectively.

According to exemplary embodiments, the discharge pressure of the carboxylic acid monomer and the polar co-solvent (for example, the discharge pressure from the discharge portion 40) may be greater than the inlet pressure or the mixing pressure at the mixing portion 30. have.

In some embodiments, the discharge pressure may be greater than the copolymerization reaction pressure in reactor 60.

For example, the discharge pressure may be maintained in the range of 1100 to 2500 bar. Preferably, the discharge pressure may range from 1300 to 2300 bar.

Ethylene may be moved through the third flow passage 55 to contact the mixture of carboxylic acid monomer and polar co-solvent supplied through the discharge flow passage 45. Subsequently, copolymerization of the carboxylic acid monomer and ethylene in the reactor 60 proceeds to prepare an ethylene-carboxylic acid copolymer (eg, EAA copolymer).

In some embodiments, the aforementioned polymerization initiator may be introduced together into the reactor 60 through the third flow path 55 or through a separate flow path.

In one embodiment, the polymerization initiator is not introduced into the mixing unit 30, but can be introduced only into the reactor 60. Therefore, it is possible to prevent the self-polymerization of the carboxylic acid monomer by the polymerization initiator from being promoted first.

In some embodiments, during the polymerization process, for example, a chain transfer agent may be introduced through the third flow path 55. The molecular weight and molecular weight distribution of the polymer product can be easily controlled to a desired range through a chain transfer agent.

Polar cosolvents can also have a chain transfer effect on the polymerization of ethylene-carboxylic acid comonomers. Therefore, by adjusting the amount of the chain transfer agent and the polar co-solvent in consideration of the chain transfer coefficient (Cs) of the polar co-solvent, the polar co-existence while effectively controlling the molecular weight and molecular weight distribution of the ethylene-carboxylic acid copolymer The effect of every injection can be realized.

The chain transfer agent may include, for example, a non-polar organic compound such as isobutane and propine, or a polar organic compound such as methyl ethyl ketone, isopropylaldehyde, and vinyl acetate.

In some embodiments, the polar cosolvent interacts with the chain transfer agent inside the reactor to influence molecular weight control.

)는 반응기 전단 유로(예를 들면, 제3 유로(55))에서의 극성 공용매와 사슬 전달제의 농도, 각각의 사슬 전달계수를 종합적으로 고려하여 식 2의 범위를 만족하도록 조절될 수 있다.In some embodiments, the input concentration of the polar co-solvent included in the reaction progress index (

) Can be adjusted to satisfy the range of Equation 2 by comprehensively considering the concentration of the polar co-solvent and the chain transfer agent in the reactor shear flow path (eg, the third flow path 55), and the respective chain transfer coefficients. .

[Equation 2]

및

는 각각 반응기 전단 유로에서의 극성 공용매와 사슬 전달제(CTA)의 각각의 몰 농도이다.

와

는 200℃에서의 극성 공용매와 사슬 전달제(CTA)의 에틸렌에 대한 사슬이동계수(Cs value)이다.

And

Is the respective molar concentration of the polar co-solvent and chain transfer agent (CTA) in the reactor shear flow path, respectively.

Wow

Is the chain transfer coefficient (Cs value) for ethylene of the polar co-solvent and chain transfer agent (CTA) at 200°C.

The chain transfer coefficient is a constant representing the reactivity of the chain transfer agent that terminates the polymer polymerization reaction, and the larger the chain transfer coefficient value, the less the amount of chain transfer agent required to reduce the molecular weight of the polymer in the polymer polymerization process.

Specific values of the chain transfer coefficient can be found in Polymer Science & Technology, Joel R. Fried, 2006, 2nd edition, p.34~39, Handbook of polymer synthesis part A, Hans R. Kricheldorf, 1991, p. 3-5, Polymer science and engineering, David J. Williams, p. 103-104 et al.

For example, when it is outside the numerical range related to chain delivery expressed by Equation 2, chain termination may be excessively activated or chain extension may be excessively performed, making it difficult to implement molecular weight control.

,

를 고려하여 식 2의 범위를 만족하도록

,

를 조절함으로써 고분자 제품의 분자량 및 분자량 분포에 대한 극성 공용매의 영향을 컨트롤 할 수 있다. 예를 들면, 식 2의

를 만족하도록 식 1에서의 주입부에서의 극성 공용매의 농도(

)를 조절할 수 있다.According to exemplary embodiments,

,

Considering to satisfy the range of Equation 2

,

By controlling the effect of the polar co-solvent on the molecular weight and molecular weight distribution of the polymer product can be controlled. For example, in Equation 2

The concentration of the polar cosolvent at the injection part in Equation 1 so that

) Can be adjusted.

As shown in FIG. 1, the mixture of the carboxylic acid monomer and the polar co-solvent is mixed with ethylene before being injected into the reactor 60 to improve polymerization efficiency in the reactor 60. In one embodiment, a mixture of a carboxylic acid monomer and a polar cosolvent, and ethylene may be injected together into the reactor 60.

For example, the polymerization temperature in the reactor 60 may be 170 to 270 ^o C. The pressure in the reactor 60 may be 1100 to 2500 bar.

According to exemplary embodiments, the content of ethylene (for example, the content of ethylene-derived units or blocks) in the total weight of the ethylene-carboxylic acid copolymer is 60 to 98% by weight and the carboxylic acid content (for example , The content of units or blocks derived from carboxylic acids) may be 2 to 40% by weight. Within the above range, the self-polymerization of the carboxylic acid monomer, the purity reduction due to the by-products of the ester can be sufficiently prevented. In a preferred embodiment, the ethylene content may be 75 to 97.5% by weight, and the carboxylic acid content (eg, the content of carboxylic acid-derived units or blocks) may be 2.5 to 25% by weight.

For example, the weight average molecular weight of the copolymer produced from the reactor 60 may be 8,000 to 1,000,000.

According to the exemplary embodiments described above, it is possible to reduce crystallization and self polymerization of the carboxylic acid monomer while suppressing side reactions by controlling the reaction kinetic properties between the carboxylic acid monomer and the polar cosolvent. Accordingly, the above-described side effects due to by-products such as ethyl acrylate can be prevented or reduced while improving the yield and purity of the ethylene-carboxylic acid copolymer.

The above-described ethylene-carboxylic acid copolymer may be commercialized in the form of, for example, pellets, and used as an adhesive film, a sealing material, an insulating coating layer, a packaging film, and the like.

2 is a schematic process flow diagram for explaining a method for preparing an ethylene-carboxylic acid copolymer according to some exemplary embodiments.

Referring to FIG. 2, the carboxylic acid monomer and the polar co-solvent may be stored and supplied together in the storage tank 65. For example, a mixture of a carboxylic acid monomer and a polar co-solvent from the storage tank 65 may be transferred to the discharge portion 75 through the transfer channel 70. The mixture may be discharged from the discharge portion 75 through the discharge flow path 80.

Ethylene stored in the ethylene supply unit 50 may be moved through the third flow path 55 to contact a mixture of a carboxylic acid monomer and a polar co-solvent supplied through the discharge flow path 80. Subsequently, copolymerization of the carboxylic acid monomer and ethylene in the reactor 60 proceeds to prepare an ethylene-carboxylic acid copolymer (eg, EAA copolymer).

Even in the embodiment of FIG. 2, a process may be designed and performed to satisfy the RPI range according to the exemplary embodiments described above. For example, in equation 1, t may represent the contact time of the carboxylic acid monomer and the polar co-solvent after introduction into the storage tank 65 and until it meets ethylene.

In some embodiments, a chain transfer agent may be supplied to satisfy Equation 2 through the third flow passage 55.

Hereinafter, embodiments of the present invention will be further described with reference to specific experimental examples. The examples and comparative examples included in the experimental examples are only illustrative of the present invention and are not intended to limit the scope of the appended claims, and various changes and modifications to the examples are possible within the scope and technical thought scope of the present invention. It is obvious to those skilled in the art, and it is natural that such modifications and corrections fall within the scope of the appended claims.

Experimental Example 1

Acrylic acid (AA) (containing 200 ppm MEHQ (mono methyl ether hydroquinone) as inhibitor, 99.5% purity, Alfa Aeser) and ethanol (EtOH) (99.5%) to simulate the occurrence of side reaction products due to contact with carboxylic acid monomer and polar cosolvent Purity, Sigma Aldrich) The amount of ethyl acrylate generated in the mixture was sampled over time and the internal standard was added, and then measured with a gas chromatography-flame ionization detector (GC-FID).

In Experimental Examples 1-1 to 1-9, the EtOH/AA mixing ratio and the contact temperature were adjusted as described in Table 1.

3 to 11 are graphs showing the amount of ethyl acrylate generated over time in Experimental Examples 1-1 to 1-9, respectively.

Referring to FIGS. 3 to 11, it was possible to observe the tendency of ethyl acrylate to occur linearly with time. The relationship between the amount of ethyl acrylate generated (y) according to the time (x) derived according to the linear regression analysis is described in FIGS. 3 to 11, respectively.

Specifically, in the same temperature condition, the larger the EtOH/AA molar ratio, and the higher the reaction temperature in the same EtOH/AA molar ratio, the more the production of ethyl acrylate was promoted.

It is necessary to secure a process operation range capable of preventing self-polymerization and crystallization of the carboxylic acid monomer by lowering the crystallization temperature of the mixture in the discharge part 40 through the introduction of a polar co-solvent. Accordingly, the minimum contact time (or residence time) of the mixture was set to 0.1 seconds in order to properly mix the carboxylic acid monomer and the polar co-solvent to be introduced into the reactor 60.

As described above, the allowable level of ethyl acrylate in the discharge section 40 in the plant process simulation model to satisfy the 6 ppm standard of side reaction product (ethyl acrylate) in the final product was set to 600 ppm.

The reaction progress index (RPI) (lower limit) according to the minimum contact time for each experiment of 0.1 seconds and the RPI (upper limit) at the contact time corresponding to the upper limit of the ethyl acrylate generation of 600 ppm were calculated and listed in Table 1.

Reactant molar ratio Reaction temperature (℃) Reaction progress index
(RPI)(sec.K) Acrylic acid
(AA) Polar cosolvent
(EtOH) Lower limit
(Contact time 0.1 second) maximum Experimental Example 1-1 One One 25 29.8 1.3 E+07 Experimental Example 1-2 6 One 25 5.0 4.6 E+06 Experimental Example 1-3 20 One 25 1.5 3.9 E+06 Experimental Example 1-4 One One 50 32.3 1.8 E+06 Experimental Example 1-5 6 One 50 5.4 5.7 E+05 Experimental Example 1-6 20 One 50 1.6 4.5 E+05 Experimental Example 1-7 One One 75 34.8 3.1 E+05 Experimental Example 1-8 6 One 75 5.8 9.4 E+04 Experimental Example 1-9 20 One 75 1.7 7.4 E+04

Referring to Table 1, when the RPI is adjusted between 1.5 and 1.3Х10 ⁷ sec·K, the amount of side reaction products (ethyl acrylate) is easily managed below the target value while securing a wide process operation range through the introduction of a polar co-solvent. You can confirm that you can. When the RPI is less than 1.5, a polar cosolvent cannot be effectively introduced into the reactor effectively. When the RPI exceeds 1.3Х10 ⁷ sec·K, it exceeds the controllable regulatory range of ethyl acrylate in the final product and may cause the above-described side effects.

On the other hand, the RPI (lower limit) with the minimum contact time set to 1 second in order to secure a sufficient range of process operation through the polar cosolvent and the RPI (upper limit) at the contact time to satisfy the actual ethyl acrylate regulation standard of 6ppm are calculated. Thus, it is described in Table 2. Specifically, the contact time corresponding to 6 ppm was calculated through a relational expression of the amount of ethyl acrylate generated (y) according to the time (x) described in FIGS. 3 to 11, respectively.

Reactant molar ratio Reaction temperature (℃) Reaction progress index
(RPI)(sec.K) Acrylic acid
(AA) Polar cosolvent
(EtOH) Lower limit
(Contact time 1 second) maximum
(Ethyl acrylate 6ppm) Experimental Example 1-1 One One 25 298 1.3 E+05 Experimental Example 1-2 6 One 25 49.7 4.6 E+04 Experimental Example 1-3 20 One 25 14.9 3.9 E+04 Experimental Example 1-4 One One 50 323 1.8 E+05 Experimental Example 1-5 6 One 50 53.8 5.7 E+03 Experimental Example 1-6 20 One 50 16.2 4.5 E+03 Experimental Example 1-7 One One 75 348 3.1 E+03 Experimental Example 1-8 6 One 75 58 9.4 E+02 Experimental Example 1-9 20 One 75 17.4 7.4 E+02

Referring to Table 2, when the RPI is adjusted between 14.9 and 1.3Х10 ⁵ sec·K, it can be seen that the amount of side reaction products can be suppressed to less than the actual standard while increasing the contact time of the polar co-solvent realistically.

Experimental Example 2

Through the process simulation model of the ethylene-acrylic acid copolymer polymerization process, the molar concentration of the chain transfer agent and the polar co-solvent in the reactor 60 shear flow path was measured, and thus the value of Equation 2 described above was calculated.

Description Polar co-solvent Chain transfer agent (CTA) Equation 2 value division [C](mol/L) Cs value division [C](mol/L) Cs value Experimental Example 2-1 isobutane 0.3067 0.0136 0.004 Experimental Example 2-2 MEK 0.0614 0.0750 0.005 Experimental Example 2-3 ethanol 0.2982 0.0135 isobutane 0.3016 0.0136 0.008 Experimental Example 2-4 ethanol 0.4731 0.0135 isobutane 0.1754 0.0136 0.009

As described above, the molecular weight and molecular weight distribution of the copolymer can be appropriately adjusted within the numerical range of Equation 2. Moreover, the influence on the molecular weight distribution by use of a polar cosolvent can be appropriately controlled within the numerical range of Equation 2.

For example, when the numerical value of Equation 2 is less than the lower limit (0.003 mol/L), the total amount of the compound acting as a chain transfer function in the reactor becomes insufficient, so that the average molecular weight of the product may be too large or the molecular weight distribution may be too wide. When the numerical value of Equation 2 is greater than the upper limit (0.01 mol/L), the total amount of the compound that has a chain transfer function in the reactor increases, and the average molecular weight of the product may be too small or the molecular weight distribution may be too narrow.

Referring to Table 3, through the chain transfer agent function of the polar co-solvent itself, it can be confirmed that even if the polar co-solvent is newly introduced, the content of the chain transfer agent can be reduced to maintain the calculated value of Equation 2 within the range of Equation 2. Can be.

10: carboxylic acid monomer supply unit 20: polar cosolvent supply unit
15: first euro 25: second euro
30: mixing unit 35, 70: transfer flow path
40, 75: discharge part 45, 80: discharge flow path
50: ethylene supply part 55: third flow path
60: reactor 65: storage tank

Claims (15)

Forming a mixture of a carboxylic acid monomer and an organic solvent-based polar co-solvent; And
Injecting the mixture and ethylene into a reactor to copolymerize,
In the step of forming a mixture of the carboxylic acid monomer and the organic solvent-based polar cosolvent, the Reaction Progress Index (RPI) defined by the following Equation 1 is in the range of 1.5 to 1.3×10 ⁷ sec·K. Controlling the amount of side reaction products of the carboxylic acid monomer and the polar co-solvent by adjusting, the method for producing an ethylene-carboxylic acid copolymer:
[Equation 1]

(Equation 1

Wow

Is an initial molar concentration of the polar co-solvent and the carboxylic acid monomer , t denotes the contact time of the carboxylic acid monomer and the polar co-solvent, and T is ethylene of the carboxylic acid monomer and the polar co-solvent. It is the average contact temperature before overreaction). The method according to claim 1, wherein the reaction progress index is 14.9 to 1.3 × 10 ⁵ sec·K range, a method for producing an ethylene-carboxylic acid copolymer. The method of claim 1, further comprising discharging the mixture. The method of claim 3, wherein the discharge pressure of the mixture is greater than the mixing pressure of the carboxylic acid monomer and the polar co-solvent. The method of claim 4, wherein the discharge pressure is greater than the pressure in the reactor. The method according to claim 3, wherein the step of forming the mixture comprises introducing the carboxylic acid monomer and the polar co-solvent into a mixing unit, respectively,
The step of discharging the mixture may include moving the mixture from the mixing unit to the discharge unit through a transfer flow path; And
A method for producing an ethylene-carboxylic acid copolymer comprising discharging the mixture from the discharge portion through a discharge passage. The method according to claim 1, wherein the temperature of the mixture is above the crystallization temperature of the carboxylic acid monomer, and is maintained below the self-polymerization temperature of the carboxylic acid monomer, a method for producing an ethylene-carboxylic acid copolymer. The method of claim 1, wherein the mixture is contacted with ethylene before being injected into the reactor. The method of claim 1, further comprising injecting a reaction inhibitor between the carboxylic acid monomer and the polar co-solvent into the mixture. The method for producing an ethylene-carboxylic acid copolymer according to claim 9, wherein the reaction inhibitor comprises an amine-based compound. The method according to claim 1, further comprising the step of injecting a chain transfer agent through the shear flow path of the reactor to the mixture, a method for producing an ethylene-carboxylic acid copolymer. The method of claim 11, wherein the chain transfer agent comprises a non-polar organic compound. The method of claim 12, wherein the chain transfer agent comprises methyl ethyl ketone or isobutane. The method for producing an ethylene-carboxylic acid copolymer according to claim 11, which satisfies the following formula:
[Equation 2]

(In formula 2,

And

Is the molar concentration of the polar cosolvent and the chain transfer agent in the shear flow path of the reactor, respectively,

Wow

Is the chain transfer coefficient (Cs) for ethylene of the polar cosolvent and the chain transfer agent at 200°C). The method according to claim 1, wherein the carboxylic acid monomer comprises acrylic acid, and the polar co-solvent comprises ethanol.

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