Method for producing ethylene-vinyl ester copolymer saponified pellets

Abstract

To provide a method for producing EVOH pellets having high dimensional stability and productivity.SOLUTION: There is provided a method for producing pellets of an ethylene-vinyl ester copolymer saponification product, which comprises: a coagulation step in which a solution of an ethylene-vinyl ester copolymer saponification product is extruded in a strand shape into a coagulation liquid to obtain a coagulated product; and a cutting step of cutting the coagulated product to obtain pellets, wherein in the solidification step, the discharge speed of the strand extruded into the coagulation liquid is 1.3 kg / (hour / hole) or more and the coagulation liquid contains at least one salt selected from the group consisting of an inorganic acid salt and an organic acid salt in an amount of 2 mass% or more and 25 mass% or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for producing saponified pellets of an ethylene-vinyl ester copolymer.

Background Art

[0002] The saponified product of an ethylene-vinyl ester copolymer (hereinafter sometimes abbreviated as EVOH) is a material excellent in oxygen barrier property, oil resistance, non-charging property, mechanical strength, etc., and is widely used after being formed into films, sheets, containers, etc. As a method for producing EVOH, a method of saponifying an ethylene-vinyl ester copolymer obtained by polymerizing ethylene and a vinyl ester such as vinyl acetate in an organic solvent containing alcohol in the presence of a saponification catalyst is common.

[0003] As a post-treatment method for an alcohol solution of saponified EVOH, a method of extruding the alcohol solution of EVOH in a strand shape into a coagulating liquid such as water or a water / methanol solution and then cutting the strand to produce pellets is widely used. At this time, stabilizing the cutability of the strand is important for preventing strand breakage and improving the dimensional stability of the pellets. Patent Document 1 describes that by containing a predetermined amount of carboxylate in the coagulating liquid, EVOH pellets with excellent size accuracy can be continuously produced. On the other hand, it is described that if the concentration of the carboxylate is too high or too low, inconveniences such as an increase in the curing time of the strand or strand breakage will occur.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] To increase the production rate of EVOH, it is necessary to increase the discharge rate of the EVOH solution during pelletizing. However, in conventional methods, increasing the discharge rate can lead to cutting errors when cutting the strands, resulting in decreased productivity and insufficient dimensional stability of the resulting pellets. For these reasons, there has been a need to improve the cutability of strands made of hydrated EVOH.

[0006] This invention was made to solve the above problems and aims to provide a method for manufacturing EVOH pellets with high dimensional stability and productivity. [Means for solving the problem]

[0007] The above problems are solved by providing a method for producing EVOH pellets, which includes a solidification step of obtaining a solid by extruding an EVOH solution in strand form into a solidifying liquid and allowing it to solidify, and a cutting step of cutting the solidified material to obtain pellets, wherein in the solidification step, the discharge rate of the strands extruded into the solidifying liquid is 1.3 kg / (hour·hole) or more, and the solidifying liquid contains 2% by mass or more and 25% by mass or less of at least one salt selected from the group consisting of inorganic salts and organic salts.

[0008] In this case, it is preferable that the coagulation solution contains water and methanol. It is also preferable that the salt contained in the coagulation solution is at least one selected from the group consisting of carboxylates, sulfates, nitrates, and carbonates. [Effects of the Invention]

[0009] The manufacturing method of the present invention produces EVOH pellets with high productivity because the strand-like solidified material containing EVOH has good cutability. The EVOH pellets thus obtained can be suitably used as a material for various molded products. [Modes for carrying out the invention]

[0010] The present invention relates to a method for producing EVOH pellets, comprising a solidification step of obtaining a solid by extruding an EVOH solution in strand form into a solidification liquid and allowing it to solidify, and a cutting step of cutting the solidified material to obtain pellets, wherein in the solidification step, the discharge rate of the strand extruded into the solidification liquid is 1.3 kg / (hour·hole) or more, and the solidification liquid contains 2% to 25% by mass of at least one salt selected from the group consisting of inorganic salts and organic salts. In this method, the cutability of the strand-shaped solidified material containing EVOH is good, resulting in high productivity and high dimensional stability of the resulting EVOH pellets. The present invention will be described in detail below.

[0011] First, the method for synthesizing EVOH will be described. EVOH is obtained by saponifying an ethylene-vinyl ester copolymer. As the vinyl ester, fatty acid vinyl esters such as vinyl acetate, vinyl propionate, and vinyl pivalate can be used, but vinyl acetate is preferred. Polymerization of ethylene and vinyl ester may be carried out by solution polymerization, suspension polymerization, emulsion polymerization, or bulk polymerization, but solution polymerization is preferred. It may also be carried out in a continuous or batch manner.

[0012] In solution polymerization, alcohols are preferred as the solvent, but other organic solvents capable of dissolving ethylene, vinyl esters, and ethylene-vinyl acetate copolymers (such as dimethyl sulfoxide) can also be used. Suitable alcohols include methanol, ethanol, 1-propanol, and 2-propanol, with methanol being industrially preferred.

[0013] As polymerization catalysts, azonitrile-based initiators such as 2,2-azobisisobutyronitrile, 2,2-azobis-(2,4-dimethylvaleronitrile), 2,2-azobis-(4-methyl-2,4-dimethylvaleronitrile), 2,2-azobis-(4-methoxy-2,4-dimethylvaleronitrile), and 2,2-azobis-(2-cyclopropylpropionitrile), as well as organic peroxide-based initiators such as isobutyryl peroxide, cumyl peroxyneodecanoate, diisopropyl peroxycarbonate, di-n-propyl peroxydicarbonate, t-butyl peroxyneodecanoate, lauroyl peroxide, benzoyl peroxide, and t-butyl hydroperoxide can be used.

[0014] The polymerization temperature is preferably 20 to 90°C, more preferably 40 to 70°C. The polymerization time (average residence time in the case of continuous polymerization) is preferably 2 to 15 hours, more preferably 3 to 11 hours. The polymerization rate is preferably 10 to 90 mol%, more preferably 30 to 80 mol%, relative to the input vinyl ester. The polymer concentration in the solution after polymerization is preferably 5 to 85% by mass, more preferably 20 to 70% by mass. The ethylene unit content of the ethylene-vinyl ester copolymer is the same as that of EVOH, which will be described later. In addition, the ethylene-vinyl ester copolymer can also be copolymerized with small amounts of other monomers, but the type and amount of other monomers used are the same as those used for EVOH, which will be described later.

[0015] After polymerization for a predetermined time and reaching a predetermined polymerization rate, a polymerization inhibitor is added as needed, and unreacted ethylene gas is evaporated and removed, followed by the removal of unreacted vinyl ester. As a method for removing unreacted vinyl ester from the ethylene-vinyl ester copolymer solution from which ethylene has been evaporated, for example, the copolymer solution is continuously supplied at a constant rate from the top of a column packed with Raschig rings, and an organic solvent vapor such as methanol is blown in from the bottom of the column, causing a mixed vapor of the organic solvent such as methanol and unreacted vinyl ester to distill out from the top of the column, and the copolymer solution from which the unreacted vinyl ester has been removed is taken out from the bottom of the column.

[0016] An alkaline catalyst is added to the ethylene-vinyl ester copolymer solution from which unreacted vinyl ester has been removed, and the vinyl ester component in the copolymer is saponified. The saponification method can be continuous or batch, but it is preferable to carry out the saponification reaction continuously using a tower reactor and collect the EVOH solution from the bottom of the tower. Sodium hydroxide, potassium hydroxide, alkali metal alcohols, etc., can be used as the alkaline catalyst. Alcohols such as methanol and ethanol are preferred as the solvent used for saponification, and methanol is more preferred industrially. When using a tower reactor, it is preferable to supply methanol vapor from the bottom of the tower and distill off methyl acetate from the top of the tower.

[0017] The preferred saponification conditions are as follows: The concentration of ethylene-vinyl ester copolymer in the reaction solution is preferably 10 to 50% by mass, and more preferably 20 to 45% by mass. The reaction temperature is preferably 70 to 150°C, and more preferably 80 to 140°C. The amount of catalyst used is preferably 0.005 to 1 equivalent, and more preferably 0.01 to 0.5 equivalents, relative to the number of moles of vinyl ester units. The reaction time (average residence time in the case of a continuous reaction) is preferably 10 minutes to 6 hours, and more preferably 15 minutes to 2 hours. The saponification reaction is carried out in this manner to obtain a solution of EVOH. The EVOH content in the solution is preferably 10 to 50% by mass, and more preferably 20 to 45% by mass.

[0018] The degree of saponification of the vinyl ester units of the EVOH obtained in this way is preferably 80 to 100 mol%. From the viewpoint of obtaining a molded product with excellent barrier properties, it is more preferably 95 mol% or more, even more preferably 98 mol% or more, and particularly preferably 99 mol% or more. If the degree of saponification is less than 80 mol%, the barrier properties, long-run properties, and moisture resistance may be poor.

[0019] In the present invention, the ethylene unit content of EVOH is preferably 20 to 60 mol% from the viewpoint of obtaining a molded product with excellent barrier properties and melt moldability. If the ethylene unit content is less than 20 mol%, melt moldability may be poor. More preferably, the ethylene unit content is 23 mol% or more. On the other hand, if the ethylene unit content exceeds 60 mol%, the barrier properties may be insufficient. More preferably, the ethylene unit content is 55 mol% or less, and even more preferably 50 mol% or less.

[0020] EVOH can also be copolymerized with small amounts of other monomers, as long as the objectives of the present invention are not hindered. Examples of copolymerizable monomers include alkenes such as propylene, butylene, pentene, and hexene; 3-acyloxy-1-propene, 3-acyloxy-1-butene, 4-acyloxy-1-butene, 3,4-diasiloxy-1-butene, 3-acyloxy-4-methyl-1-butene, 4-acyloxy-2-methyl-1-butene, and 4-acyloxy-3-methyl -1-butene, 3,4-diasiloxy-2-methyl-1-butene, 4-acyloxy-1-pentene, 5-acyloxy-1-pentene, 4,5-diasiloxy-1-pentene, 4-acyloxy-1-hexene, 5-acyloxy-1-hexene, 6-acyloxy-1-hexene, 5,6-diasiloxy-1-hexene, 1,3-diacetoxy-2-methyl Examples include alkenes having ester groups such as npropane or their saponides; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, and itaconic acid, or their anhydrides, salts, or mono- or dialkyl esters; nitriles such as acrylonitrile and methacrylonitrile; amides such as acrylamide and methacrylamide; olefin sulfonic acids such as vinylsulfonic acid, allylsulfonic acid, and methallylsulfonic acid, or their salts; vinylsilane compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(β-methoxy-ethoxy)silane, and γ-methacryloxypropylmethoxysilane; alkyl vinyl ethers, vinyl ketones, N-vinylpyrrolidone, vinyl chloride, and vinylidene chloride. When EVOH has other monomer units, the copolymerization amount is preferably 10 mol% or less, and more preferably 5 mol% or less.

[0021] The solvent used in the EVOH solution subjected to the solidification step is not particularly limited as long as it is a good solvent for EVOH, but a mixed solvent containing water and alcohol is preferred. That is, it is preferable to use a water / alcohol solution of EVOH in the solidification step. Here, the water / alcohol solution of EVOH refers to a solution in which EVOH is dissolved in the mixed solvent containing water and alcohol. Examples of alcohols that can be used in this case include methanol, ethanol, propanol, butanol, etc., with methanol being industrially preferred.

[0022] The method for producing the EVOH solution used in the solidification step is not particularly limited. The EVOH solution after the saponification reaction may be used directly in the solidification step, or a solvent may be added to the EVOH solution after the saponification reaction, or at least a portion of the solvent in the EVOH solution after the saponification reaction may be replaced with the same or a different solvent before being used in the solidification step.

[0023] As the water / alcohol solution of the EVOH to be subjected to the coagulation step, that obtained by replacing a part of the alcohol in the EVOH solution after the saponification reaction with water can be subjected to the coagulation step. At this time, as a method of replacing a part of the alcohol in the alcohol solution of the EVOH with water, a method of adding a mixed vapor of a solvent (alcohol) and water to the alcohol solution in a container and vaporizing the solvent (alcohol) from the solution is preferable. As the container at this time, a tower-type container such as a tray tower or a packed tower is preferable. In this case, the alcohol solution of the EVOH is introduced from the upper part of the tower, a mixed vapor of a solvent (alcohol) and water is introduced from the lower part of the tower-type container, and they are brought into countercurrent contact, and a mixed vapor of a solvent (alcohol) and water is led out from the upper part of the tower, and a part of the solvent present in the alcohol solution of the EVOH to be supplied is replaced with water, and a high-concentration water / alcohol solution of EVOH can be obtained from the bottom of the tower. Further, it is preferable that the water content in the mixed vapor is 20 to 70% by mass. The solvent used for the mixed vapor is preferably an alcohol having a boiling point of 130°C or lower, and examples of such an alcohol include alcohols such as methanol, ethanol, propanol, and butanol. An alcohol having a boiling point of 100°C or lower is more preferable, and among them, methanol is preferable in terms of being easily available, inexpensive, having a low boiling point, and being easy to handle. By performing solvent replacement in this way, a water / alcohol solution of EVOH can be obtained. The mass ratio of water / alcohol of the water / alcohol solution of the EVOH to be subjected to the coagulation step is preferably 10 / 90 to 60 / 40, and more preferably 20 / 80 to 50 / 5*.

[0024] The content of the EVOH in the EVOH solution to be subjected to the coagulation step is preferably 20 to 50% by mass. By setting the content of the EVOH within this range, the fluidity of the EVOH solution is ensured and efficient resin production is possible. From the viewpoint of increasing the production amount per unit time, the content is more preferably 25% by mass or more, and even more preferably 35% by mass or more. The content of components other than EVOH and the solvent in the EVOH solution is usually 10% by mass or less.

[0025] *There seems to be a typo in the original text where it says "50 / 5*". It should probably be "50 / 50". This has been noted in the translation as "50 / 5*".As the coagulation liquid used in the coagulation step, one containing a poor solvent for the EVOH is used. As the poor solvent, water and a mixed solvent containing water and alcohol are preferable, and a mixed solvent containing water and alcohol is more preferable. As the alcohol used in the mixed solvent, methanol, ethanol, propanol, etc. are used, but methanol is preferably used industrially. The mass ratio of water to alcohol (water / alcohol) contained in the mixed solvent is preferably 70 / 30 to 98 / 2. The mass ratio (water / alcohol) is more preferably 80 / 20 or more. The content of the poor solvent in the coagulation liquid is preferably 60% by mass or more, and more preferably 75% by mass or more. On the other hand, the content is preferably 98% by mass or less.

[0026] The coagulation solution must contain at least one salt selected from the group consisting of inorganic salts and organic salts in an amount of 2% to 25% by mass. Conventionally, a method of adding a predetermined amount of carboxylate salt to the coagulation solution was known as a way to improve the cutability of strands obtained by extruding an EVOH solution into the coagulation solution. However, when the discharge rate of the EVOH solution is increased to increase the production rate of EVOH, cutting errors occur when cutting the strands, which can reduce productivity or result in insufficient dimensional stability of the resulting pellets, and improvement was needed. In response to this, the inventors diligently studied how to improve the cutability and found that increasing the salt concentration and, as described later, increasing the discharge rate of the EVOH solution improves the cutability of the strands. Conventionally, it has been known that if the concentration of carboxylate salt in the coagulation solution is too high, the hardening time of the strands tends to increase and the cutability tends to decrease, so obtaining such an effect is truly surprising. Organic salts are preferred as the salt contained in the coagulation solution. Examples of organic salts include carboxylate salts and sulfonates, with carboxylate salts being preferred. Examples of the inorganic salt include sulfates, nitrates, carbonates, hydrochlorides, and phosphates, with sulfates, nitrates, and carbonates being particularly preferred. Furthermore, it is preferable that the cation constituting the salt is a cation of a metal belonging to Group 1 or Group 2 of the periodic table, and more preferably a cation of a metal belonging to Group 1 of the periodic table. Examples of metal cations belonging to Group 1 of the periodic table include sodium ions, potassium ions, and lithium ions, with sodium ions and potassium ions being preferred, and sodium ions being more preferred. Examples of metal cations belonging to Group 2 of the periodic table include calcium ions and magnesium ions. Specifically, sodium acetate is preferred from the viewpoint of ease of handling.

[0027] The salt content in the coagulation solution is 2% by mass or more, which improves the cutting performance. Furthermore, the salt content is 25% by mass or less from the viewpoint of suppressing salt precipitation in the coagulation solution.

[0028] The temperature of the coagulation solution is preferably between -10°C and 40°C. If the temperature is below -10°C, the coagulation solution may freeze. The temperature is more preferably above -5°C, and even more preferably above 0°C. On the other hand, if the temperature exceeds 40°C, the EVOH may not coagulate sufficiently. The temperature is more preferably below 30°C, even more preferably below 25°C, even more preferably below 20°C, and particularly preferably below 15°C.

[0029] The EVOH solution is extruded in a strand-like manner into the solidification liquid by a nozzle having any shape. The shape of the nozzle is not particularly limited, but a cylindrical shape is preferred. The inner diameter of the nozzle can be adjusted as appropriate depending on the diameter of the target EVOH pellet, but is usually 1 to 10 mm.

[0030] In the present invention, the discharge rate of the strands extruded into the solidification solution must be 1.3 kg / (hour / hole) or higher. This improves the production rate of EVOH, and as described above, by increasing the salt concentration in the solidification solution, the cutability of the strands remains stable even at high discharge rates, thus enabling the highly productive production of EVOH. Here, the discharge rate [kg / (hour / hole)] refers to the amount (kg) of strands (EVOH solution) extruded per hour from one nozzle hole (discharge port). From the viewpoint of further improving the production rate of EVOH, the discharge rate is preferably 1.8 kg / (hour / hole) or higher, and more preferably 2.5 kg / (hour / hole) or higher. On the other hand, from the viewpoint of further improving cutability, the discharge rate is preferably 10 kg / (hour / hole) or lower, and 5 k g / (hour / hole) or less is more preferable. In the present invention, the strand to be extruded does not necessarily have to be a single strand, and any number between several and several hundred strands can be extruded. That is, there does not have to be one nozzle (strand discharge port), and there can be any number between several and several hundred.

[0031] The contact time between the strand-shaped extruded EVOH and the coagulation solution is preferably 5 seconds or more. If the contact time is less than 5 seconds, the EVOH solution may not coagulate sufficiently. The contact time is more preferably 10 seconds or more, even more preferably 20 seconds or more, even more preferably 30 seconds or more, and particularly preferably 40 seconds or more. On the other hand, from the viewpoint of productivity, the contact time is preferably 30 minutes or less, more preferably 10 minutes or less, and even more preferably 5 minutes or less.

[0032] The EVOH extruded in strand form is pulled out of the coagulation bath by a take-up roller attached to the edge of the coagulation bath, then cut to obtain EVOH pellets. The take-up speed of the take-up roller can be adjusted to control the contact time with the coagulation liquid and the diameter of the resulting EVOH pellets. The take-up speed of the take-up roller is preferably 1.5 to 5.0 m / min, more preferably 2.0 to 4.5 m / min, and even more preferably 2.5 to 4.5 m / min.

[0033] The strand-like solidified material containing EVOH obtained in this way is cut to obtain EVOH pellets. The method of cutting the solidified material is not particularly limited, and methods using a strand cutter, hot cutter, underwater cutter, etc. are possible. Among these, it is preferable to cut the solidified material using a strand cutter. The length of the EVOH pellet immediately after cutting is preferably 1 to 10 mm. If the EVOH pellet is cylindrical, its diameter is preferably 1 to 10 mm.

[0034] From the standpoint of further improving cutability, the moisture content of the EVOH pellets immediately after cutting is preferably 30 to 80% by mass. A moisture content of 35% by mass or more is more preferable. On the other hand, a moisture content of 70% by mass or less is more preferable, 50% by mass or less is even more preferable, and 45% by mass or less is particularly preferable.

[0035] The resulting hydrated EVOH pellets may be subjected to washing and drying steps as needed. Washing solutions used in the washing step include water, aqueous solutions containing acids such as acetic acid, and aqueous solutions containing alcohols such as methanol. Drying methods for the hydrated EVOH pellets used in the drying step include hot air drying and infrared irradiation.

[0036] The hydrated EVOH pellets may be subjected to chemical treatment as necessary. This treatment may include impregnating the hydrated EVOH pellets with an aqueous solution containing an arbitrary additive. Examples of such additives include carboxylic acids, boron compounds, phosphoric acid compounds, alkali metal salts, and alkaline earth metal salts.

[0037] The resulting EVOH pellets are then molded into various types of molded products such as films, sheets, containers, pipes, and fibers by melt molding. [Examples]

[0038] The present invention will be described in more detail below using examples, but the present invention is not limited in any way by these examples.

[0039] [Evaluation Method] (1) Strand cutability evaluation In the manufacturing process of the hydrated EVOH pellets obtained in the examples and comparative examples, approximately 2,500 pellets were obtained by cutting 10m of strand-shaped hydrated EVOH (coagulated material) and visually inspected them, and evaluated for the following items. Can the strand be cut continuously? (Yes / No) • Number of times the cutter was stopped due to a cutting defect where pellets were stuck together for 3 cm or more in a row. • Number of pellets that are connected and cannot be cut (pieces) • Number of hydrated EVOH pellets with crushed cross-sections (pieces)

[0040] (2) Moisture content of water-containing EVOH pellets The moisture content of the hydrated EVOH pellets obtained in the examples and comparative examples immediately after cutting was measured using a Mettler HR73 halogen moisture meter.

[0041] (3) Dimensional stability 100 EVOH pellets were randomly selected from the examples and comparative examples, and their diameter and length were measured. The percentage of pellets whose diameter and length fell within ±0.2 mm of the average value was then determined.

[0042] [Examples] (Example 1) A container having a nitrogen inlet and a cylindrical nozzle with an inner diameter of 0.3 cm and a length of 6.0 cm was filled with an EVOH solution (water / methanol solution (mass ratio 50 / 50)) containing 40% by mass of EVOH (ethylene-vinyl acetate copolymer saponified product) with an ethylene unit content of 27 mol% and a degree of saponification of 99 mol%. By controlling the amount of nitrogen introduced through the nitrogen inlet, the EVOH solution was discharged in strand form from the cylindrical nozzle at a rate of 2 kg / (h·hole) into a solidification bath consisting of a 5°C water / methanol solution (mass ratio 95 / 5) containing 3% by mass of sodium acetate. A take-up roller attached to the end of the solidification bath was used to pull out the generated strand-shaped solidified material from the solidification solution so that the residence time in the solidification bath was 60 seconds. The strands pulled out from the solidification solution were cut with a cutter to obtain porous, water-containing EVOH pellets. A φ60mm / 100mm rotary blade with eight equally spaced blades was used to cut the strand. The rotation speed of the blade was adjusted so that the peripheral speed of the blade was the take-up speed + 0.05 m / min, and the strand was cut. The obtained water-containing EVOH pellets were evaluated for their cutability and water content according to the methods described in evaluation methods (1) and (2) above. The results are shown in Table 1. The water-containing EVOH pellets were washed in a water bath at 30°C for 1 hour, this was repeated four times, and then washed again in acetic acid water at 30°C for 1 hour. After drying, the EVOH pellets of the present invention (cylindrical white pellets with an average diameter of 3.8 mm and an average length of 4 mm) were obtained.

[0043] (Examples 2-7, Comparative Examples 1-4) Except for changing the discharge rate and coagulation bath conditions as shown in Table 1, hydrated EVOH pellets and EVOH pellets were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1. In Comparative Example 4, the salt concentration in the coagulation bath was too high, causing sodium acetate to precipitate in the coagulation bath, which prevented stable discharge of the strands, and therefore evaluation could not be performed.

[0044] [Table 1]

Claims

1. A method for producing ethylene-vinyl ester copolymer saponified pellets, comprising a solidification step of obtaining a solidified product by extruding a solution of ethylene-vinyl ester copolymer saponified into a solidification liquid in the form of strands and allowing it to solidify, and a cutting step of cutting the solidified product to obtain pellets, wherein in the solidification step, the discharge rate of the strands extruded into the solidification liquid is 1.3 kg / (hour / hole) or more and 5 kg / (hour / hole) or less, and the solidification liquid contains 2% by mass or more and 25% by mass or less of at least one salt selected from the group consisting of carboxylates, sulfates and nitrates.

2. The method for producing ethylene-vinyl ester copolymer saponified pellets according to claim 1, wherein the coagulation solution contains water and methanol.

3. A method for producing ethylene-vinyl ester copolymer saponified pellets according to claim 1 or 2, wherein the salt contained in the coagulation liquid is at least one selected from the group consisting of carboxylates, sulfates, nitrates, and carbonates.

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