Ethylene-(meth) acrylate copolymer, method for producing same, and composition

Abstract

The ethylene-(meth) acrylate copolymer according to the present invention has a decomposition initiation temperature of 350 DEG C or more as measured by thermogravimetric-differential thermal measurement in air at a temperature rise rate of 20.0 DEG C / min.

Description

Technical Field

[0001] The present invention relates to an ethylene-(meth)acrylate copolymer, a method for producing the same, and a composition. Background Art

[0002] Polymers are used in molded articles for various purposes. For example, Patent Documents 1 and 2 describe a coating layer for an electric wire formed from a polymer composition.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Laid-Open No. 8-50810

[0006] Patent Document 2: Japanese Patent Laid-Open No. 2020-015812 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] However, when a film is formed from a polymer, defects in a shape similar to that of fish eyes (hereinafter sometimes referred to as "fish eyes") sometimes occur in the film.

[0009] The present invention has been made in view of such circumstances, and an object thereof is to provide an ethylene-(meth)acrylate copolymer capable of forming a film with a reduced number of fish eyes, and a composition using the same. Another object of the present invention is to provide a method for producing the above ethylene-(meth)acrylate copolymer.

[0010] Means for Solving the Problems

[0011] The present invention relates to an ethylene-(meth)acrylate copolymer. For this ethylene-(meth)acrylate copolymer, the decomposition start temperature measured by thermogravimetry-differential thermal measurement under air and at a heating rate of 20.0 °C / minute is 350 °C or higher. According to such an ethylene-(meth)acrylate copolymer, a film with a reduced number of fish eyes can be formed.

[0012] Preferably, the above ethylene-(meth)acrylate copolymer has a weight average molecular weight Mw of 90,000 or less, and the content of the structural unit derived from (meth)acrylate is 20 to 30% by mass. According to such an ethylene-(meth)acrylate copolymer, a film with a reduced number of fish eyes can be formed, and the fluidity during molding in the form of a film can be improved and the transparency of the film can be improved.

[0013] The present invention also relates to a composition comprising: polymer particles containing the above ethylene-(meth)acrylate copolymer, and a silicon compound attached to the surface of the polymer particles. According to such a composition, a film with a reduced number of fisheyes can be formed, and the mutual adhesion of the polymer particles can be reduced.

[0014] Relative to the mass of the polymer particles, the above composition preferably contains a silicon compound in an amount of 20 mass ppm or more in terms of dimethylsiloxane conversion. Thereby, the mutual adhesion of the polymer particles can be further reduced.

[0015] The above ethylene-(meth)acrylate copolymer is preferably an ethylene-methyl methacrylate copolymer.

[0016] The present invention also relates to a method for producing an ethylene-(meth)acrylate copolymer, which uses a tank reactor having an upper reaction zone and a lower reaction zone and in which a fluid flows from the upper reaction zone to the lower reaction zone, polymerizes ethylene and (meth)acrylate, and supplies streams F1 to Fn (n is an integer of 2 or more) containing ethylene and (meth)acrylate to the tank reactor at ratios R1 to Rn and temperatures T i 1 to T i n. The temperature is measured at a position downstream of the midpoint in the flow direction of the lower reaction zone. When this temperature is designated as T4, ΔT calculated by the following formula (I) 2 is 150°C or higher. According to such a method, the above ethylene-(meth)acrylate copolymer can be easily produced.

[0017] [Mathematical formula 1]

[0018]

[0019] [The ratio Rk (k is an integer of 1 or more and n or less) represents the mass flow rate of the stream Fk relative to the total mass flow rate of the streams F1 to Fn.]

[0020] In the above method for producing an ethylene-(meth)acrylate copolymer, it is preferred that at least one of the streams F1 to Fn is supplied to the upper reaction zone and at least one of the streams F1 to Fn is supplied to the lower reaction zone. Further, in the above method for producing an ethylene-(meth)acrylate copolymer, n is preferably 3 or more.

[0021] In the above method for producing an ethylene-(meth)acrylate copolymer, it is preferred that the temperature is measured at a position upstream of the midpoint in the flow direction of the lower reaction zone. When this temperature is designated as T3, ΔT calculated by the following formula (II) 1 is 12°C or higher.

[0022] ΔT1 =T4 [°C] - T3 [°C] … (II)

[0023] Advantages of the Invention

[0024] According to the present invention, an ethylene-(meth)acrylate copolymer capable of forming a film with a reduced number of fish eyes, and a composition using the same can be provided. Further, according to the present invention, a method for producing the above ethylene-(meth)acrylate copolymer can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a diagram for explaining a method for producing an ethylene-(meth)acrylate copolymer. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, embodiments of the present invention will be described in detail with appropriate reference to the drawings as needed. The dimensional ratios in the drawings are not limited to the ratios shown in the drawings.

[0027] [Ethylene-(meth)acrylate copolymer]

[0028] For the ethylene-(meth)acrylate copolymer of the present embodiment, the decomposition start temperature measured by thermogravimetry-differential thermal analysis (TG-DTA) under the conditions of air and a heating rate of 20.0 °C / minute is 350 °C or higher. According to such an ethylene-(meth)acrylate copolymer, a film with a reduced number of fish eyes can be formed.

[0029] The decomposition start temperature can be obtained by the following method: using a high-temperature type differential thermal and thermogravimetric simultaneous measurement device, and using the weight reduction curve measured under the conditions of an air atmosphere, a flow rate of 200 ml / minute, and a heating rate of 20.0 °C / minute, and according to JIS K7120, setting the temperature of the intersection of the mass line before the start of measurement and the tangent line with the maximum slope of the TG curve as the decomposition start temperature, and thus obtaining it.

[0030] More specifically, the decomposition start temperature can be determined based on the following steps 1 to 3.

[0031] 1: Draw a line (a-b) parallel to the horizontal axis passing through the mass 0 before the start of the test heating.

[0032] 2: Draw a tangent line (c-d) so that the slope between the inflection points in the TG curve becomes the maximum.

[0033] 3: Take the temperature of the intersection point of the line (a-b) and the tangent line (c-d) as the decomposition start temperature.

[0034] From the viewpoint of being more likely to further reduce fish eyes, the above decomposition start temperature can be, for example, 355°C or higher, or can be 360°C or higher. The above decomposition start temperature can be, for example, 500°C or lower, can be 450°C or lower, or can be 400°C or lower. The above decomposition start temperature can be, for example, 350 to 500°C, can be 355 to 450°C, or can be 360 to 400°C.

[0035] In this specification, “(meth)acrylate” means the general term for acrylate and methacrylate.

[0036] Examples of the (meth)acrylate include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, hexyl methacrylate, octyl methacrylate, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, tert-butyl acrylate, and isobutyl acrylate.

[0037] Examples of the above ethylene-(meth)acrylate copolymer include ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-n-propyl acrylate copolymer, ethylene-isopropyl acrylate copolymer, ethylene-n-butyl acrylate copolymer, ethylene-tert-butyl acrylate copolymer, ethylene-isobutyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl methacrylate copolymer, ethylene-n-propyl methacrylate copolymer, ethylene-isopropyl methacrylate copolymer, ethylene-n-butyl methacrylate copolymer, ethylene-tert-butyl methacrylate copolymer, and ethylene-isobutyl methacrylate copolymer.

[0038] From the viewpoint of being more likely to improve the transparency of the film, the content of the structural unit derived from (meth)acrylate in the above ethylene-(meth)acrylate copolymer can be, for example, 5% by mass or more, can be 10% by mass or more, or can be 20% by mass or more. From the viewpoint of maintaining the crystallinity of the ethylene-(meth)acrylate copolymer, the content of the structural unit derived from (meth)acrylate in the above ethylene-(meth)acrylate copolymer can be, for example, 50% by mass or lower, can be 40% by mass or lower, or can be 30% by mass or lower. The content of the structural unit derived from (meth)acrylate in the above ethylene-(meth)acrylate copolymer can be, for example, 5 to 50% by mass, can be 10 to 40% by mass, or can be 20 to 30% by mass.

[0039] The content of the structural unit derived from ethylene in the above ethylene-(meth)acrylate copolymer may be, for example, 50% by mass or more, may be 60% by mass or more, or may be 70% by mass or more. The content of the structural unit derived from ethylene in the above ethylene-(meth)acrylate copolymer may be, for example, 95% by mass or less, may be 90% by mass or less, or may be 80% by mass or less. The content of the structural unit derived from (meth)acrylate in the above ethylene-(meth)acrylate copolymer may be, for example, 50 to 95% by mass, may be 60 to 90% by mass, or may be 70 to 80% by mass.

[0040] From the viewpoint of easy film formation, the weight-average molecular weight Mw of the above ethylene-(meth)acrylate copolymer may be, for example, 10,000 or more, may be 20,000 or more, or may be 30,000 or more. From the viewpoint of easily improving the fluidity during molding, the weight-average molecular weight Mw of the above ethylene-(meth)acrylate copolymer may be, for example, 250,000 or less, may be 90,000 or less, or may be 80,000 or less. The weight-average molecular weight Mw of the above ethylene-(meth)acrylate copolymer may be, for example, 10,000 to 250,000, may be 20,000 to 90,000, or may be 30,000 to 80,000.

[0041] The weight-average molecular weight (Mw) refers to the value determined by measuring using gel permeation chromatography (GPC) under the following conditions with polystyrene as the standard substance.

[0042] Measuring equipment: HLC-8321 (product name, manufactured by Tosoh Corporation, GPC / HT type)

[0043] Separation column: Two TSKgel GMH6-HT (column size: inner diameter 7.5 mm, length 300 mm) and two TSKgel GMH6-HTL (column size: inner diameter 7.5 mm, length 300 mm)

[0044] Column temperature: 140 °C

[0045] Mobile phase: o-dichlorobenzene (manufactured by Wako Pure Chemical Industries, Ltd.) (wherein, 0.025% by weight of BHT (manufactured by Wako Pure Chemical Industries, Ltd.) is contained as an antioxidant)

[0046] Flow rate: 1.0 mL / minute

[0047] Sample concentration: 30 mg / 20 mL

[0048] Sample injection volume: 0.4 mL

[0049] Detector: Differential refractometer

[0050] Standard specimen: TSK standard polystyrene manufactured by Tosoh Corporation

[0051] From the viewpoint of easily improving the fluidity during film formation and the transparency of the film, the weight-average molecular weight Mw of the above ethylene-(meth)acrylate copolymer is preferably 90,000 or less, and the content of the structural unit derived from (meth)acrylate is preferably 20 to 30% by mass.

[0052] For the above ethylene-(meth)acrylate copolymer, the melt flow rate (MFR) measured according to the method specified in JIS K7210-1995 under the conditions of a load of 21.18 N and a temperature of 190 °C can be, for example, 500 g / 10 minutes or less, can be 300 g / 10 minutes or less, and can also be 200 g / 10 minutes or less. This melt flow rate can be, for example, 1 g / 10 minutes or more.

[0053] From the viewpoints of less odor and high thermal decomposition temperature, the above ethylene-(meth)acrylate copolymer is preferably an ethylene-methyl methacrylate copolymer.

[0054] [Composition]

[0055] The composition of the present embodiment includes: polymer particles containing the above ethylene-(meth)acrylate copolymer, and a silicon compound adhered to the surface of the polymer particles. The composition of the present embodiment is, for example, a particulate composition. According to the composition of the present embodiment, a film with a reduced number of fish eyes can be formed, and the mutual adhesion of polymer particles can be reduced. Therefore, according to this composition, a film with few fish eyes can be stably manufactured at a high production rate.

[0056] The content of the ethylene-(meth)acrylate copolymer in the polymer constituting the polymer particles can be, for example, 90% by mass or more, can be 95% by mass or more, and can also be 99% by mass or more. The content of the ethylene-(meth)acrylate copolymer relative to the total mass of the polymer particles can be, for example, 90 to 100% by mass, can be 95 to 100% by mass, can be 99 to 100% by mass, and can also be 100% by mass.

[0057] The above polymer particles are, for example, granules. The particle size of the above polymer particles is not limited and can be, for example, 0.01 mm or more, can be 0.1 mm or more, and can also be 1 mm or more. This particle size can be, for example, 20 mm or less, can be 10 mm or less, and can also be 5 mm or less. The particle size of the above polymer particles can be 0.01 to 20 mm, can be 0.1 mm to 10 mm, and can also be 1 mm to 5 mm.

[0058] Examples of the silicon compound include siloxanes typified by polydimethylsiloxane, silicon monoxide, silicon dioxide, silicic acid, silicon nitride, silicon carbide, silicate, silicon tetrachloride, silane, cyclic siloxane, and the like.

[0059] In the above composition, from the viewpoint of further easily reducing the mutual adhesion of the polymer particles, a silicon compound may be contained in an amount of, for example, 20 mass ppm or more, 25 mass ppm or more, or 30 mass ppm or more in terms of dimethylsiloxane conversion relative to the mass of the polymer particles. In the above composition, a silicon compound may be contained in an amount of, for example, 300 mass ppm or less, 200 mass ppm or less, or 100 mass ppm or less in terms of dimethylsiloxane conversion relative to the mass of the polymer particles. In the above composition, a silicon compound may be contained in an amount of, for example, 20 to 300 mass ppm, 25 to 200 mass ppm, or 30 to 100 mass ppm in terms of dimethylsiloxane conversion relative to the mass of the polymer particles. In the above composition, it is preferable to contain a silicon compound in an amount of 20 mass ppm or more in terms of dimethylsiloxane conversion relative to the mass of the polymer particles.

[0060] Here, the mass of the silicon compound in terms of dimethylsiloxane conversion means the mass of dimethylsiloxane having the same amount of Si atoms as the above silicon compound.

[0061] [Method for producing ethylene-(meth)acrylate copolymer]

[0062] The ethylene-(meth)acrylate copolymer of the present embodiment can be produced, for example, by a method including a polymerization step of polymerizing ethylene and (meth)acrylate using an initiator.

[0063] The type of the initiator is not particularly limited, and examples thereof include tert-butyl perpivalate, tert-butyl peroxy-2-ethylhexanoate, and tert-butyl peroxyisopropyl carbonate. The initiator may be used alone or in combination of two or more.

[0064] It is considered that for an ethylene-(meth)acrylate copolymer having a decomposition start temperature of 350°C or higher, the randomness of the structural units derived from (meth)acrylate is high. Therefore, it is considered preferable to adjust the conditions in the polymerization step, for example, in such a way as to increase the randomness of the structural units derived from (meth)acrylate. As the conditions that can be adjusted, for example, the supply method of the raw materials containing ethylene and (meth)acrylate, the supply method, type, and amount of the initiator, the reaction temperature, and the reaction pressure can be considered.

[0065] Next, an example of the method for producing an ethylene-(meth)acrylate copolymer will be described.

[0066] In this method, a trough-shaped reactor having an upper reaction zone and a lower reaction zone with fluid flowing from the upper reaction zone to the lower reaction zone is used to polymerize ethylene and (meth)acrylate. The ethylene and (meth)acrylate are polymerized respectively under the conditions of ratios R1 to Rn and temperatures T i 1 to T i n. Streams F1 to Fn (n is an integer of 2 or more) containing ethylene and (meth)acrylate are supplied to the trough-shaped reactor. The temperature is measured at a position downstream of the midpoint in the flow direction of the lower reaction zone. When this temperature is designated as T4, ΔT calculated by the following formula (I) 2 is 150°C or higher. According to such a method, the ethylene-(meth)acrylate copolymer of the present embodiment can be easily produced.

[0067] [Mathematical formula 2]

[0068]

[0069] [The ratio Rk (k is an integer of 1 or more and n or less) represents the mass flow rate of the stream Fk relative to the total mass flow rate of the streams F1 to Fn.]

[0070] In this method, the temperature is measured at a position upstream of the midpoint in the flow direction of the lower reaction zone. When this temperature is designated as T3, ΔT calculated by the following formula (II) 1 is preferably 12°C or higher.

[0071] ΔT 1 = T4 [°C] - T3 [°C] … (II)

[0072] ΔT 2 For example, it can be 155°C or higher, it can be 160°C or higher, and it can also be 165°C or higher. ΔT 2 For example, it can be 200°C or lower, it can be 195°C or lower, and it can also be 190°C or lower.

[0073] ΔT 1 For example, it can be 14°C or higher, it can be 16°C or higher, and it can also be 18°C or higher. ΔT 1 For example, it can be 30°C or lower, it can be 28°C or lower, and it can also be 25°C or lower.

[0074] T4 can be 200°C or higher, for example, it can be 210°C or higher, and it can also be 220°C or higher. T4 can be 300°C or lower, for example, it can be 275°C or lower, and it can also be 250°C or lower.

[0075] T3 can be, for example, above 188°C, above 198°C, or above 208°C. T3 can be, for example, below 288°C, below 263°C, or below 238°C.

[0076] Temperature T i 1 to T i n can be, for example, above 50°C. Temperature T i 1 to T i n can be, for example, below 100°C.

[0077] The mass ratio of ethylene to (meth)acrylate in the material flows F1 to Fn (ethylene / (meth)acrylate) can be, for example, 10 or more. The mass ratio of ethylene to (meth)acrylate in the material flows F1 to Fn (ethylene / (meth)acrylate) can be, for example, 50 or less.

[0078] For this method, it is preferred to supply at least one of the material flows F1 to Fn to the upper reaction zone and at least one of the material flows F1 to Fn to the lower reaction zone.

[0079] In this method, n is preferably 3 or more. n can be, for example, 5 or less, or can be 3.

[0080] For example, in this method, a Figure 1 manufacturing apparatus 100 as such can be used.

[0081] Figure 1 The manufacturing apparatus 100 shown mainly includes a reactor 10. The reactor 10 is a trough-shaped reactor having an upper reaction zone and a lower reaction zone, and in which fluid flows from the upper reaction zone to the lower reaction zone. The reactor 10 is divided into two reaction zones (an upper reaction zone and a lower reaction zone) by a baffle (baffle 5). Thereby, the situation where the polymer obtained by the reaction flows from the lower reaction zone to the upper reaction zone is suppressed. In addition, the reactor 10 is equipped with a stirrer (not shown) for stirring the inside of the reactor, and the baffle 5 is connected to this stirrer.

[0082] The reactor 10 has five inlets (10t, 10a, 10b, 10c, 10d) and one outlet (10e). A raw material containing ethylene and (meth)acrylate is supplied from three of the inlets (inlets 10t, 10a, and 10b), and initiators (initiators 1 and 2) are supplied from two inlets (inlets 10c and 10d). The inlet 10t is provided at the upper part of the tower. The inlets 10a and 10c are provided in a region above the baffle 5 (upper reaction region). In addition, the inlets 10b and 10d are provided in a region below the baffle 5 (lower reaction region). In the reactor 10, ethylene and (meth)acrylate are copolymerized by the initiator. The polymer obtained by the reaction is discharged to the pipeline LB through the outlet 10e provided at the bottom of the reactor 10.

[0083] Ethylene and (meth)acrylate respectively pass through pipelines L1 and L2 and merge, and then are pressurized to a specified pressure by a compressor (not shown). Next, they are distributed to pipelines L3 (feed stream F3), L4 (feed stream F2), and L5 (feed stream F1) equipped with heat exchangers HE3, HE2, and HE1, and are supplied to the reactor 10 from the inlets 10b, 10a, and 10t. The initiator 1 is supplied to the reactor 10 from the inlet 10c through the pipeline L6. The initiator 2 is supplied to the reactor from the inlet 10d through the pipeline L7.

[0084] The reactor 10 is successively equipped with four thermometers TR1, TR2, TR3, and TR4 from above the reactor. The thermometers TR1 and TR2 are provided in a region above the baffle 5, and TR3 and TR4 are provided in a region below the baffle 5. The thermometer TR1 measures the temperature T1 at a position upstream of the midpoint in the flow direction of the upper reaction region, the thermometer TR2 measures the temperature T2 at a position downstream of the midpoint in the flow direction of the upper reaction region, the thermometer TR3 measures the temperature T3 at a position upstream of the midpoint in the flow direction of the lower reaction region, and the thermometer TR4 measures the temperature T4 at a position downstream of the midpoint in the flow direction of the lower reaction region. In addition, the inlet 10c of the initiator 1 is provided close to the thermometer TR1, and the inlet 10d of the initiator 2 is provided close to the thermometer TR3.

[0085] It is considered that for the above manufacturing apparatus 100, it is easy to adjust the supply ratio and temperature of each of the raw materials (raw materials containing ethylene and (meth)acrylate) supplied from the inlets 10t, 10a, and 10b, and the type and amount of the initiators supplied to the inlets 10c and 10d. Therefore, it is considered that the ethylene-(meth)acrylate copolymer of the present embodiment can be easily manufactured according to such an apparatus.

[0086] Next, an example of a method for manufacturing an ethylene-(meth)acrylate copolymer using the manufacturing apparatus 100 will be described.

[0087] First, the streams F1 to F3 containing ethylene and (meth)acrylate are respectively supplied to the reactor 10 via pipelines L5, L4 and L3 at ratios R1 to R3 and temperatures T i 1 to T i 3. Here, R1 represents the mass flow rate of stream F1 relative to the total mass flow rate of streams F1 to F3, R2 represents the mass flow rate of stream F2 relative to the total mass flow rate of streams F1 to F3, and R3 represents the mass flow rate of stream F3 relative to the total mass flow rate of streams F1 to F3.

[0088] The temperature T i 1 to T i 3, and the mass ratio of ethylene to (meth)acrylate (ethylene / (meth)acrylate) in streams F1 to F3 can be set appropriately.

[0089] The ratios R1 to R3 are not limited. The ratio of the stream supplied to the upper reaction zone to the stream supplied to the lower reaction zone (mass flow rate of the stream supplied to the upper reaction zone / mass flow rate of the stream supplied to the lower reaction zone) can be, for example, 1 / 3 to 3 / 1, can be 1 / 2 to 2 / 1, can be 2 / 3 to 3 / 2, or can be 1 / 1.

[0090] In addition, the initiator is supplied to the reactor 10 via pipelines L6 and L7. The initiator can be, for example, the above-mentioned initiator. The initiator supplied from pipeline L6 and the initiator supplied from pipeline L7 can be the same or different.

[0091] In the reactor 10, ethylene and (meth)acrylate are polymerized under the condition that ΔT calculated by the following formula (Ia) 2 is 150 °C or higher.

[0092] ΔT 2 = T4 [°C] - (R1 × T i 1 [°C] + R2 × T i 2 [°C] + R3 × T i 3 [°C])... (Ia)

[0093] ΔT 2 For example, it can be 155 °C or higher, can be 160 °C or higher, or can be 165 °C or higher. ΔT 2 For example, it can be 200 °C or lower, can be 195 °C or lower, or can be 190 °C or lower.

[0094] The pressure inside the reactor 10 is not limited and can be set to, for example, 160 to 200 MPa.

[0095] ΔT calculated by the following formula (IIa)1 Preferably, it is 12 °C or higher.

[0096] ΔT 1 = T4 [°C] - T3 [°C] … (IIa)

[0097] ΔT 1 For example, it can be 14 °C or higher, it can be 16 °C or higher, or it can be 18 °C or higher. ΔT 1 For example, it can be 30 °C or lower, it can be 28 °C or lower, or it can be 25 °C or lower.

[0098] T4 can be, for example, 200 °C or higher, it can be 210 °C or higher, or it can be 220 °C or higher. T4 can be, for example, 300 °C or lower, it can be 275 °C or lower, or it can be 250 °C or lower.

[0099] T3 can be, for example, 188 °C or higher, it can be 198 °C or higher, or it can be 208 °C or higher. T3 can be, for example, 288 °C or lower, it can be 263 °C or lower, or it can be 238 °C or lower.

[0100] In addition, T1 and T2 can be set to 200 to 250 °C, for example.

[0101] After the obtained ethylene-(meth)acrylate copolymer is withdrawn through pipeline LB, it is purified as needed.

[0102] [Method for manufacturing the composition]

[0103] The composition of the present embodiment can be manufactured, for example, by a method including a granulation step of granulating an ethylene-methyl methacrylate copolymer (for example, into particles), and an attachment step of attaching a silicon compound to the obtained particles. The granulation step and the attachment step can be carried out sequentially or simultaneously.

[0104] As a specific example of this method, there can be mentioned: a method of supplying a composition containing an ethylene-methyl methacrylate copolymer to an extruder, and then cutting the composition extruded from the extruder while cooling it with cooling water containing a silicon compound.

[0105] The preferred embodiments of the present invention have been described above, but the present invention is not limited thereto.

[0106] The present invention relates to the following matters.

[0107] [1] An ethylene-(meth)acrylate copolymer, for which the decomposition start temperature measured by thermogravimetry-differential thermal measurement under air and at a heating rate of 20.0 °C / minute is 350 °C or higher.

[0108] [2] The ethylene-(meth)acrylate copolymer according to [1] has a weight-average molecular weight Mw of 90,000 or less, and the content of the structural unit derived from (meth)acrylate is 20 to 30% by mass.

[0109] [3] A composition comprising: polymer particles containing the ethylene-(meth)acrylate copolymer according to [1] or [2], and a silicon compound attached to the surface of the polymer particles.

[0110] [4] In the composition according to [3], in the above composition, the silicon compound is contained in an amount of 20 mass ppm or more in terms of dimethylsiloxane, relative to the mass of the polymer particles.

[0111] [5] The ethylene-(meth)acrylate copolymer according to [1] or [2] is an ethylene-methyl methacrylate copolymer.

[0112] [6] A method for producing an ethylene-(meth)acrylate copolymer, which uses a tank reactor having an upper reaction zone and a lower reaction zone and in which a fluid flows from the upper reaction zone to the lower reaction zone, and polymerizes ethylene and (meth)acrylate, wherein feeds F1 to Fn (n is an integer of 2 or more) containing ethylene and (meth)acrylate are supplied to the tank reactor at ratios R1 to Rn and temperatures T i 1 to T i n, and the temperature is measured at a position downstream of the midpoint in the flow direction of the lower reaction zone. When this temperature is set as T4, ΔT calculated by the following formula (I) 2 is 150°C or more.

[0113] [Mathematical formula 3]

[0114]

[0115] [The ratio Rk (k is an integer from 1 to n) represents the mass flow rate of the feed Fk relative to the total mass flow rate of the feeds F1 to Fn.]

[0116] [7] In the method for producing an ethylene-(meth)acrylate copolymer according to [6], at least one of the feeds F1 to Fn is supplied to the upper reaction zone, and at least one of the feeds F1 to Fn is supplied to the lower reaction zone.

[0117] [8] In the method for producing an ethylene-(meth)acrylate copolymer according to [6] or [7], n is 3 or more.

[0118] [9]The production process of ethylene-(meth)acrylate copolymer according to any one of [6] to [8], wherein the temperature is measured at a position upstream of the midpoint in the flow direction of the lower reaction zone, and when this temperature is designated as T3, ΔT calculated by the following formula (II) 1 is 12°C or higher,

[0119] ΔT 1 = T4 [°C] - T3 [°C] … (II)

[0120] [Examples]

[0121] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the following examples.

[0122] [Example 1]

[0123] Ethylene and methyl methacrylate were copolymerized using Figure 1 the production equipment to produce ethylene-methyl methacrylate copolymer. For the raw materials supplied to inlets 10t, 10a, and 10b, the ethylene / methyl methacrylate ratio (mass ratio) in the composition was set to 15.7, and the pressure was set to 169 MPa.

[0124] 3 / 8 of the total mass flow rate per unit time of the raw materials supplied to reactor 10 was supplied to reactor 10 from inlet 10t, 1 / 8 from inlet 10a, and 4 / 8 from inlet 10b. That is, the ratios R1, R2, and R3 of the material flows F1, F2, and F3 were set to 3 / 8, 1 / 8, and 4 / 8, respectively. In addition, the supply temperatures of the raw materials were: inlet 10t (T i 1) was 60°C, inlet 10a (T i 2) was 60°C, and inlet 10b (T i 3) was 92°C.

[0125] In addition, tert-butyl perpivalate was supplied from inlet 10c, and a mixture of tert-butyl 2-ethylhexanoate peroxide and tert-butyl isopropyl carbonate peroxide was supplied from inlet 10d.

[0126] The reaction pressure inside the reactor was set to 169 MPa. In addition, the temperatures inside the reactor were measured using thermometers TR1 to TR4. The temperature of thermometer TR1 was designated as T1, the temperature of thermometer TR2 was designated as T2, the temperature of thermometer TR3 was designated as T3, and the temperature of thermometer TR4 was designated as T4, as shown in Table 1 respectively. T3 is the temperature measured at a position upstream of the midpoint in the flow direction of the lower reaction zone, and T4 is the temperature measured at a position downstream of the midpoint in the flow direction of the lower reaction zone.

[0127] The reaction temperature T4 near the outlet 10e (polymer extraction outlet) at the lower part of the reactor is 234 °C. Additionally, if the difference between T4 and T3 (T4 [°C] - T3 [°C]) in the lower reaction region of the trough-shaped reactor is defined as ΔT 1 , then ΔT 1 is 20.5 °C. According to the ratios (R1 to 3) and temperatures (T i 1 to 3) of the raw materials supplied from inlets 10t, 10a, and 10b, and ΔT calculated based on T4 2 is 157.8 °C.

[0128] Here, ΔT 2 is calculated as follows.

[0129] ΔT 2 = T4 [°C] - (R1 × T i 1 [°C] + R2 × T i 2 [°C] + R3 × T i 3 [°C])

[0130] The produced ethylene-methyl methacrylate copolymer is supplied to the extruder via pipeline LB. The copolymer extruded from the extruder is granulated while being cooled with cooling water containing a silicon compound and cut. Thus, granules containing ethylene-methyl acrylate copolymer particles and the silicon compound attached to the surface of the particles are obtained. As the cooling water containing a silicon compound, cooling water containing 0.82 L of DETACK Fortis EC9052A (component containing a silicon compound) per 1 ton of the mass of the ethylene-methyl methacrylate copolymer is used. The amount of the silicon compound in the obtained granules is 40 mass ppm in terms of dimethyl silicone conversion relative to the mass of the copolymer particles.

[0131] [Example 2]

[0132] Ethylene and methyl methacrylate are copolymerized using the Figure 1 manufacturing apparatus to produce an ethylene-methyl methacrylate copolymer. For the raw materials supplied to inlets 10t, 10a, and 10b, the ethylene / methyl methacrylate ratio (mass ratio) in the composition is set to 18.2, and the pressure is set to 170 MPa.

[0133] 3 / 8 of the total mass flow rate per unit time of the raw materials supplied to reactor 10 is supplied to reactor 10 from inlet 10t, 1 / 8 is supplied to reactor 10 from inlet 10a, and 4 / 8 is supplied to reactor 10 from inlet 10b. That is, the ratios R1, R2, and R3 of the material flows F1, F2, and F3 are set to 3 / 8, 1 / 8, and 4 / 8, respectively. Additionally, the supply temperatures of the raw materials are: inlet 10t (T i 1) is 59 °C, inlet 10a (T i2) is 60 °C, inlet 10b (T i 3) is 91 °C.

[0134] In addition, tert-butyl perpivalate is supplied from inlet 10c, and a mixture of tert-butyl peroxy-2-ethylhexanoate and tert-butyl peroxyisopropyl carbonate is supplied from inlet 10d.

[0135] The reaction pressure in the reactor is set to 170 MPa. The temperatures T1, T2, T3, and T4 are measured in the same manner as in Example 1, and ΔT 1 and ΔT 2 are calculated. The results are shown in Table 1.

[0136] The produced ethylene-methyl methacrylate copolymer is supplied to an extruder via pipeline LB. The copolymer extruded from the extruder is granulated while being cooled with cooling water containing a silicon compound and cut. Thus, granules containing ethylene-methyl acrylate copolymer particles and a silicon compound attached to the surface of the particles are obtained. As the cooling water containing a silicon compound, cooling water containing 0.35 L of DETACK Fortis EC9052A (a component containing a silicon compound) per 1 ton of the mass of the ethylene-methyl methacrylate copolymer is used. The amount of the silicon compound in the obtained granules is 4 mass ppm in terms of dimethyl silicone conversion relative to the mass of the copolymer particles.

[0137] [Example 3]

[0138] Using Figure 1 a production apparatus, ethylene and methyl methacrylate are copolymerized to produce an ethylene-methyl methacrylate copolymer. For the raw materials supplied to inlets 10t, 10a, and 10b, the ethylene / methyl methacrylate ratio (mass ratio) in the composition is set to 23.2, and the pressure is set to 175 MPa.

[0139] 3 / 8 of the total mass flow rate per unit time of the raw materials supplied to reactor 10 is supplied to reactor 10 from inlet 10t, 1 / 8 is supplied to reactor 10 from inlet 10a, and 4 / 8 is supplied to reactor 10 from inlet 10b. That is, the ratios R1, R2, and R3 of the material flows F1, F2, and F3 are set to 3 / 8, 1 / 8, and 4 / 8, respectively. In addition, the supply temperatures of the raw materials are: inlet 10t (T i 1) is 60 °C, inlet 10a (T i 2) is 60 °C, inlet 10b (T i 3) is 83 °C.

[0140] In addition, tert-butyl perpivalate is supplied from inlet 10c, and a mixture of tert-butyl peroxy-2-ethylhexanoate and tert-butyl peroxyisopropyl carbonate is supplied from inlet 10d.

[0141] The reaction pressure inside the reactor was set at 175 MPa. Temperatures T1, T2, T3, and T4 were measured in the same manner as in Example 1, and ΔT was calculated. 1 and ΔT 2 . The results are shown in Table 1.

[0142] The ethylene-methyl methacrylate copolymer produced was supplied to the extruder via pipeline LB. Granules were produced in the same manner as in Example 1, except that DETACK Fortis EC9052A (a component containing a silicon compound) was not added to the cooling water. That is, the copolymer extruded from the extruder was cooled with cooling water not containing a silicon compound while being cut, whereby ethylene-methyl methacrylate copolymer particles (granules) not adhering with a silicon compound were obtained.

[0143] [Example 4]

[0144] Using Figure 1 the production apparatus, ethylene and methyl methacrylate were copolymerized to produce an ethylene-methyl methacrylate copolymer. For the raw materials supplied to inlets 10t, 10a, and 10b, the ethylene / methyl methacrylate ratio (mass ratio) in the composition was set at 45.6, and the pressure was set at 191 MPa.

[0145] 3 / 8 of the total mass flow rate per unit time of the raw materials supplied to reactor 10 was supplied to reactor 10 from inlet 10t, 1 / 8 was supplied to reactor 10 from inlet 10a, and 4 / 8 was supplied to reactor 10 from inlet 10b. That is, the ratios R1, R2, and R3 of the material flows F1, F2, and F3 were set at 3 / 8, 1 / 8, and 4 / 8, respectively. In addition, the supply temperatures of the raw materials were: inlet 10t (T i 1) was 57 °C, inlet 10a (T i 2) was 60 °C, and inlet 10b (T i 3) was 59 °C.

[0146] In addition, tert-butyl perpivalate was supplied from inlet 10c, and a mixture of tert-butyl peroxy-2-ethylhexanoate and tert-butyl peroxyisopropyl carbonate was supplied from inlet 10d.

[0147] The reaction pressure inside the reactor was set at 191 MPa. Temperatures T1, T2, T3, and T4 were measured in the same manner as in Example 1, and ΔT was calculated. 1 and ΔT 2 . The results are shown in Table 1.

[0148] The produced ethylene-methyl methacrylate copolymer is supplied to an extruder via pipeline LB. Granules were produced in the same manner as in Example 1, except that DETACK Fortis EC9052A (a component containing a silicon compound) was not added to the cooling water. That is, the copolymer extruded from the extruder was cooled with cooling water not containing a silicon compound while being cut, whereby ethylene-methyl methacrylate copolymer particles (granules) not attached with a silicon compound were obtained.

[0149] [Comparative Example 1]

[0150] Using Figure 1 manufacturing equipment, ethylene and methyl methacrylate were copolymerized to produce an ethylene-methyl methacrylate copolymer. For the raw materials supplied to inlets 10t, 10a, and 10b, the ethylene / methyl methacrylate ratio (mass ratio) in the composition was set to 21.6, and the pressure was set to 155 MPa.

[0151] Three-eighths of the total mass flow rate per unit time of the raw materials supplied to reactor 10 was supplied to reactor 10 from inlet 10t, one-eighth was supplied to reactor 10 from inlet 10a, and four-eighths was supplied to reactor 10 from inlet 10b. That is, the ratios R1, R2, and R3 of the material flows F1, F2, and F3 were set to 3 / 8, 1 / 8, and 4 / 8, respectively. In addition, the supply temperatures of the raw materials were: 60 °C for inlet 10t (T i 1), 60 °C for inlet 10a (T i 2), and 87 °C for inlet 10b (T i 3).

[0152] In addition, tert-butyl perpivalate was supplied from inlets 10c and 10d.

[0153] The reaction pressure inside the reactor was set to 155 MPa. Temperatures T1, T2, T3, and T4 were measured in the same manner as in Example 1, and ΔT 1 and ΔT 2 were calculated. The results are shown in Table 1.

[0154] The produced ethylene-methyl methacrylate copolymer is supplied to an extruder via pipeline LB. Granules were produced in the same manner as in Example 1, except that DETACK Fortis EC9052A (a component containing a silicon compound) was not added to the cooling water. That is, the copolymer extruded from the extruder was cooled with cooling water not containing a silicon compound while being cut, whereby ethylene-methyl methacrylate copolymer particles (granules) not attached with a silicon compound were obtained.

[0155] [Comparative Example 2]

[0156] Using Figure 1The raw materials supplied to the inlets 10t, 10a and 10b had an ethylene / methyl methacrylate ratio (mass ratio) of 18.4 and a pressure of 155 MPa.

[0157] Of the total mass flow rate per unit time of the raw materials supplied to the reactor 10, 3 / 8 is supplied to the reactor 10 from the inlet 10t, 1 / 8 is supplied to the reactor 10 from the inlet 10a, and 4 / 8 is supplied to the reactor 10 from the inlet 10b. That is, the ratios R1, R2, and R3 of the streams F1, F2, and F3 are set to 3 / 8, 1 / 8, and 4 / 8, respectively. In addition, the supply temperature of the raw materials is: the inlet 10t (T i 1) is 60℃, inlet 10a (T i 2) 60°C, inlet 10b (T i 3) is 86℃.

[0158] In addition, tert-butyl peroxypivalate was supplied from inlets 10c and 10d.

[0159] The reaction pressure in the reactor was set to 155 MPa. The temperatures T1, T2, T3 and T4 were measured in the same manner as in Example 1, and ΔT was calculated. 1 and ΔT 2 The results are shown in Table 1.

[0160] The generated ethylene-methyl methacrylate copolymer was supplied to the extruder via the pipeline LB. The copolymer extruded from the extruder was cut while being cooled with cooling water not containing a silicon compound in the same manner as in Example 3, thereby obtaining ethylene-methyl methacrylate copolymer particles to which no silicon compound was attached. CHEMIPEARL V200 (manufactured by Mitsui Chemicals, Inc.) was directly sprayed on the obtained particles, thereby obtaining particles to which 800 mass ppm of CHEMIPEARL was attached relative to the mass of the copolymer particles.

[0161] [Comparative Example 3]

[0162] use Figure 1 The ethylene-methyl methacrylate copolymer was produced by copolymerizing ethylene and methyl methacrylate in the production apparatus. The raw materials supplied to the inlets 10t, 10a and 10b had an ethylene / methyl methacrylate ratio (mass ratio) of 18.3 and a pressure of 195 MPa.

[0163] Three-eighths of the total mass flow rate per unit time of the raw materials supplied to the reactor 10 is supplied to the reactor 10 from the inlet 10t, one-eighth is supplied to the reactor 10 from the inlet 10a, and four-eighths is supplied to the reactor 10 from the inlet 10b. That is, the ratios R1, R2, and R3 of the material streams F1, F2, and F3 are set to 3 / 8, 1 / 8, and 4 / 8, respectively. In addition, the supply temperature of the raw materials is: the inlet 10t (T i 1) is 57 °C, the inlet 10a (T i 2) is 55 °C, and the inlet 10b (T i 3) is 53 °C.

[0164] In addition, tert-butyl peroxypivalate is supplied from the inlets 10c and 10d.

[0165] The reaction pressure inside the reactor is set to 195 MPa. The temperatures T1, T2, T3, and T4 are measured in the same manner as in Example 1, and ΔT 1 and ΔT 2 are calculated. The results are shown in Table 1.

[0166] The produced ethylene-methyl methacrylate copolymer is supplied to an extruder via the pipeline LB and granulated by the underwater cutting method. After granulation without adding DETACK Fortis EC9052A to the cooling water, CHEMIPEARL V200 (manufactured by Mitsui Chemicals) is directly sprayed, whereby particles attached with 800 mass ppm of CHEMIPEARL are obtained.

[0167] The produced ethylene-methyl methacrylate copolymer is supplied to an extruder via the pipeline LB. The copolymer extruded from the extruder is cooled with cooling water without a silicon compound and cut in the same manner as in Example 3, whereby ethylene-methyl acrylate copolymer particles (granules) not attached with a silicon compound are obtained.

[0168]

[0169] (Evaluation)

[0170] The obtained particles are evaluated based on the following description. The results are shown in Table 2.

[0171] [Decomposition start temperature]

[0172] The decomposition start temperature is obtained as follows: Using a high-temperature differential thermal gravimetry simultaneous measurement device and using the weight reduction curve measured under the conditions of an air atmosphere, a flow rate of 200 ml / min, and a heating rate of 20.0 °C / min, and based on JIS K7120, the temperature at the intersection of the mass line before the start of measurement and the tangent line of the maximum slope of the TG curve is set as the decomposition start temperature, and thus obtained.

[0173] More specifically, the decomposition start temperature was determined based on the following steps 1 to 3.

[0174] 1: Draw a line (a - b) parallel to the horizontal axis passing through the mass 0 before the start of the test heating.

[0175] 2: Draw a tangent line (c - d) in such a way that the slope between the inflection points in the TG curve becomes the maximum.

[0176] 3: Take the temperature of the intersection point of the line (a - b) and the tangent line (c - d) as the decomposition start temperature.

[0177] [Weight - average molecular weight]

[0178] For the weight - average molecular weight (Mw), it was measured using gel permeation chromatography (GPC) under the following conditions, and polystyrene was determined as the standard substance for determination.

[0179] Measurement equipment: HLC - 8321 (product name, manufactured by Tosoh Corporation, GPC / HT type)

[0180] Separation columns: Two TSKgel GMH6 - HT (column size: inner diameter 7.5 mm, length 300 mm) and two TSKgel GMH6 - HTL (column size: inner diameter 7.5 mm, length 300 mm)

[0181] Column temperature: 140 °C

[0182] Mobile phase: o - dichlorobenzene (manufactured by Wako Pure Chemical Industries, Ltd.) (wherein, 0.025 wt% of BHT (manufactured by Wako Pure Chemical Industries, Ltd.) is contained as an antioxidant)

[0183] Flow rate: 1.0 mL / minute

[0184] Sample concentration: 30 mg / 20 mL

[0185] Sample injection volume: 0.4 mL

[0186] Detector: Differential refractometer

[0187] Standard sample: TSK standard polystyrene (16 points) manufactured by Tosoh Corporation

[0188] It should be noted that the molecular weight calculation uses the data processing software Empower3 manufactured by Waters Corporation.

[0189] [Content of structural units derived from methyl methacrylate (MMA) (unit: mass%)]

[0190] Make a tablet, and for the infrared absorption spectrum measured at 1700 cm -1The absorbance of the characteristic absorption of the carbonyl (C=O) groups appearing on the left and right is corrected by thickness, and the content of the structural unit derived from methyl methacrylate (MMA) (MMA content) is determined by the calibration curve method.

[0191] [Quantification of the amount of silicon compound (unit: mass ppm)]

[0192] To 1 g of the particles, 35 mL of diethyl ether and 5 mL of saturated NaCl solution are added, and the mixture is shaken for extraction. The resulting solution is filtered to obtain a filtrate. After evaporating the obtained filtrate, the residue is dissolved in kerosene to obtain a kerosene solution. The obtained kerosene solution is subjected to ICP-AES measurement. On the other hand, a calibration curve is prepared using polydimethylsiloxane of KF-96-100CS manufactured by Shin-Etsu Chemical Co., Ltd. By using this calibration curve, the amount of the silicon compound attached to the particles in terms of dimethylsiloxane is calculated. The amount of silicon compound in Table 2 represents the amount of the silicon compound in terms of dimethylsiloxane (unit: mass ppm) relative to the mass of the ethylene-methyl acrylate copolymer particles.

[0193] [Fish eye (FE) evaluation method]

[0194] An extruder equipped with a single-screw type screw having a diameter of 30 mm and an L / D of 28 (L is the length of the barrel of the extruder, D is the diameter of the barrel of the extruder) is used to melt-knead the resin under the conditions of 170 °C in Example 4 and 130 °C otherwise. In Example 4, it is extruded from a casting die head (250 mm wide) adjusted to 170 °C, and otherwise extruded from a casting die head (250 mm wide) adjusted to 130 °C. Then, it is cooled and solidified by being pulled with a cooling roll at 20 °C, and a casting film with a total thickness of 100 μm is wound up. The obtained film is used with a desktop CCD camera defect inspection machine (manufactured by Mamiya-OP Co., Ltd.), the sample film is spread on the stage, and the number of fish eyes (FE) with a diameter of 200 μm or more (FE count) is measured. The measurement area is set to 16.35 cm × 12 cm (0.02 m 2 ), and the light quantity is set to 70. The value of the FE count (unit: pieces / 0.02 m 2 ) is preferably small.

[0195] [Melt flow rate (MFR) (unit: g / 10 minutes)]

[0196] The measurement is carried out according to the method specified in JIS K7210-1995 under the conditions of a load of 21.18 N and a temperature of 190 °C.

[0197] [Internal haze (Haze) (unit: %)]

[0198] Using a compression molding machine of type NF-37HH / C (heating / cooling two-stage type) manufactured by Shindo Metal Industry Co., Ltd., the obtained granules were formed into a pressed sheet with a thickness of 1 mm under the conditions of heating temperature: 150 °C, preheating time: 5 minutes, heating time: 5 minutes, pressure during pressing: 5 MPa, cooling temperature: 30 °C, and cooling time: 5 minutes. Using the formed pressed sheet, the internal haze as a measure of transparency was measured using a digital haze meter (manufactured by Suga Test Instruments Co., Ltd.). The internal haze was calculated by filling a quartz cell with a dimethyl phthalate solution, immersing the specimen therein, and measuring the haze of the entire cell.

[0199] [Amount of mutual adhesion]

[0200] 120 g of the granules were put into a cylinder with a diameter of 7.5 cm and a height of 8 cm and left standing in an oven at 40 °C for 4 days. Then, a piston with a diameter of 7.3 cm and an area of 42 cm 2 and a 1-kg weight were placed on top of the cylinder, and it was left standing in an oven at 5 °C for 2 days. After standing, it was taken out of the oven at 5 °C, the piston and the weight were removed, and when the cylinder was lifted, it was visually observed whether the granules adhered to each other, and the evaluation was carried out according to the following criteria.

[0201] A: No mutual adhesion at all

[0202] B: Slight mutual adhesion of several grains was observed

[0203] C: Small mutual adhesion blocks were observed

[0204]

[0205] Explanation of reference numerals

[0206] 5... Baffle, 10... Reactor, 10t, 10a, 10c, 10b, 10d... Inlets, 10e... Outlet, 100... Manufacturing apparatus, LB, L1, L2, L3, L4, L5, L6, L7... Pipelines, HE1, HE2, HE3... Heat exchangers, TR1, TR2, TR3, TR4... Thermometers.

Claims

1. An ethylene-(meth)acrylate copolymer, for which the decomposition start temperature measured by thermogravimetry-differential thermal analysis under air and at a heating rate of 20.0 °C / minute is 350 °C or higher.

2. The ethylene-(meth)acrylate copolymer according to claim 1, wherein, the weight average molecular weight Mw is 90,000 or less, and the content of the structural unit derived from (meth)acrylate is 20% by mass to 30% by mass.

3. A composition comprising: polymer particles containing the ethylene-(meth)acrylate copolymer according to claim 1 or 2; and a silicon compound attached to the surface of the polymer particles.

4. The composition according to claim 3, wherein, in the composition, the silicon compound is contained in an amount of 20 mass ppm or more in terms of dimethylsiloxane conversion relative to the mass of the polymer particles.

5. The ethylene-(meth)acrylate copolymer according to claim 1 or 2, which is an ethylene-methyl methacrylate copolymer.

6. A method for producing an ethylene-(meth)acrylate copolymer, using a trough-shaped reactor having an upper reaction zone and a lower reaction zone and through which a fluid flows from the upper reaction zone to the lower reaction zone, and polymerizing ethylene and (meth)acrylate, wherein, At ratios R1 to Rn and temperatures T i 1 to T i n, feed streams F1 to Fn containing ethylene and (meth)acrylate are supplied to a trough-shaped reactor, where n is an integer of 2 or more. Measure the temperature at a position downstream of the midpoint of the flow direction in the lower reaction zone. When this temperature is set as T4, ΔT calculated by the following formula (I) 2 is 150 °C or higher. the ratio Rk represents the mass flow rate of the feed stream Fk relative to the total mass flow rate of the feed streams F1 to Fn, and k is an integer of 1 or more and n or less.

7. The method for producing an ethylene-(meth)acrylate copolymer according to claim 6, wherein, at least one of the feed streams F1 to Fn is supplied to the upper reaction zone, and at least one of the feed streams F1 to Fn is supplied to the lower reaction zone.

8. The method for producing an ethylene-(meth)acrylate copolymer according to claim 6 or 7, wherein, n is 3 or more.

9. The method for producing an ethylene-(meth)acrylate copolymer according to claim 6 or 7, wherein, Measure the temperature at a position upstream of the midpoint of the flow direction in the lower reaction zone. When this temperature is set as T3, ΔT calculated by the following formula (II) 1 is 12 °C or higher. ΔT 1 = T4 [°C] - T3 [°C] …(II).

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