TWI798322B - Method producing resin composition containing ethylene-vinyl alcohol copolymer and method for producing shaped article - Google Patents

Abstract

A resin composition comprising an ethylene-vinyl alcohol copolymer (A) and a compound (B) represented by the following formula (X), wherein the ethylene-vinyl alcohol copolymer (A) is ethylene The unit content is 15-60 mol%, the degree of saponification is above 85 mol%, and the content of compound (B) is 5-100ppm. This resin composition suppresses the occurrence of scorch even in repeated melt molding procedures, and is also excellent in coloring resistance under alkaline conditions.

(In formula (X), Z ¹ and Z ² are each independently a hydrogen atom or a methyl group).

Description

Method for producing resin composition containing ethylene-vinyl alcohol copolymer, and method for producing molded article

The present invention relates to a resin composition mainly composed of ethylene-vinyl alcohol copolymer, and molded articles and packaging materials using the above resin composition.

Ethylene-vinyl alcohol copolymer (hereinafter referred to as "EVOH") has excellent gas barrier properties and melt formability, and can be formed into films, sheets, pipes, pipes ( tube), bottles, etc., are widely used as packaging materials in the food field and industrial fields that require gas barrier properties. However, when the melt molding of EVOH is carried out continuously for a long time, there is a problem of scorching in the barrel, screw and die of the extruder. The occurrence of such scorch not only destabilizes the fusion molding process, but also affects the appearance and mechanical properties of the obtained molded body. Such as the reduction of quality, it is necessary to stop the operation regularly and carry out the disassembly and cleaning of the extruder. Therefore, an increase in manufacturing cost or material loss due to stop and restart of the extruder also occurs. Based on this, improvement of the charred problem is required.

In order to improve the above problems, various resin compositions containing EVOH have been developed. For example, Patent Document 1 describes a resin composition containing EVOH, a boron compound, sodium acetate, and magnesium acetate. Furthermore, it is described that the long-term workability at the time of melt molding is improved by this resin composition. Patent Document 2 describes a resin composition containing EVOH and a conjugated polyene compound. Furthermore, it is described that the resin composition suppresses the occurrence of gel and pitting caused by melt molding. Patent Document 3 describes a resin composition containing EVOH, a specific metal carboxylate, and a hindered phenolic antioxidant. Furthermore, it is described that the resin composition has excellent thermal stability and suppresses the formation of oxidative gel at high temperature. Patent Document 4 describes a resin composition containing EVOH and a specific unsaturated aldehyde. Furthermore, it is described that the resin composition suppresses the occurrence of defects such as fish eyes and gel caused by melt molding, and improves the long-term operability during melt molding.

[Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Laid-Open No. 11-60874

[Patent Document 2] Japanese Patent Application Laid-Open No. 9-71620

[Patent Document 3] Japanese Patent Application Laid-Open No. 4-227744

[Patent Document 4] International Publication No. 2013/146961

[Problems to be Solved by the Invention]

On the other hand, it is widely practiced to recover trimmed or burrs generated during the manufacture of melt-molded articles, crush and melt them again, and the present inventors found that the above-mentioned EVOH-containing resin composition was subjected to heat history many times. Sometimes, there is a problem of burning black. In addition, in recent years, the contents packaged by packaging materials have become more and more diversified, and the stability of acidic or alkaline substances in packaging materials has become particularly required. However, the present inventors have found that the above resin composition containing EVOH has the problem of easy coloring under alkaline conditions, especially high temperature conditions.

The present invention was completed based on the above circumstances, and an object of the present invention is to obtain an EVOH that suppresses the occurrence of scorch even in repeated melt molding procedures and that is excellent in coloring resistance under alkaline conditions. [means to solve the problem]

The inventors of the present invention have earnestly examined to solve the above-mentioned problems, and found that by including a compound having a specific structure in a resin composition mainly composed of EVOH, occurrence of scorch can be suppressed even in repeated melt molding processes. . In addition, the present invention has been achieved by controlling the content of the compound within an appropriate range to suppress the occurrence of scorch and improve coloring resistance under alkaline conditions. The above-mentioned problems are solved by the following inventions.

(1) A resin composition comprising an ethylene-vinyl alcohol copolymer (A) and a compound (B) represented by the following formula (X), the ethylene-vinyl alcohol copolymer (A) The content of ethylene units is 15-60 mol%, the degree of saponification is above 85 mol%, and the content of compound (B) is 5-100ppm.

(式(X)中，Z¹ 及Z² 各自獨立地為氫原子或甲基)。 (2)如(1)記載之樹脂組成物，其中以純水50ml、95℃、8小時萃取前述樹脂組成物10g而得之萃取液在20℃的pH為在4.0～5.5之範圍。 (3)如(1)或(2)記載之樹脂組成物，其係進一步含有100～400ppm的金屬離子(C)。 (4)如(1)～(3)中任一項記載之樹脂組成物，其係進一步含有50～400ppm的pKa在3.5～5.5之範圍的羧酸(D)。 惟，羧酸(D)之含量係藉由以純水50ml、95℃、8小時萃取前述樹脂組成物10g後，滴定所得之萃取液，測定而求得。 (5)一種成形體，其係包含如(1)～(4)中任一項記載之樹脂組成物。 (6)如(5)記載之成形體，其係包含由前述樹脂組成物所成之層的多層構造體。 (7)一種包裝材料，其係具有如(5)或(6)記載之成形體。 [發明的效果]

(In formula (X), Z ¹ and Z ² are each independently a hydrogen atom or a methyl group). (2) The resin composition described in (1), wherein the pH of the extract obtained by extracting 10 g of the aforementioned resin composition with 50 ml of pure water at 95° C. for 8 hours at 20° C. is in the range of 4.0 to 5.5. (3) The resin composition as described in (1) or (2), which further contains 100-400 ppm of metal ion (C). (4) The resin composition according to any one of (1) to (3), which further contains 50 to 400 ppm of carboxylic acid (D) having a pKa in the range of 3.5 to 5.5. However, the content of carboxylic acid (D) was determined by titrating the obtained extract after extracting 10 g of the aforementioned resin composition with 50 ml of pure water at 95° C. for 8 hours. (5) A molded article comprising the resin composition described in any one of (1) to (4). (6) The molded article according to (5), which is a multilayer structure including a layer composed of the aforementioned resin composition. (7) A packaging material having the molded body described in (5) or (6). [Effect of the invention]

The resin composition of the present invention suppresses the occurrence of scorch even in repeated melt molding procedures, and is also excellent in coloring resistance under alkaline conditions. In addition, since the resin composition of the present invention can be provided economically, it can be applied to various packaging materials.

[Mode of Carrying Out the Invention]

Embodiments of the present invention will be described below, but the present invention is not limited thereto. In addition, the illustrated material systems may be used alone or in combination of two or more.

＜Resin composition＞ The resin composition of the present invention contains EVOH (A) and a compound (B) represented by the following formula (X), and may contain other additives as necessary.

(In formula (X), Z ¹ and Z ² are each independently a hydrogen atom or a methyl group).

The pH of the extract obtained by extracting 10 g of the resin composition of the present invention with 50 ml of pure water at 95° C. for 8 hours at 20° C. is preferably in the range of 4.0 to 5.5. Since the pH of the extract is within this range, the pH buffering capacity of the resin composition is increased, further improving melt formability or coloring caused by acidic or alkaline substances. The pH of the extract can be controlled by changing the type or content of the metal ion (C) or carboxylic acid (D) described later. Hereinafter, each component is demonstrated.

＜EVOH(A)＞ EVOH (A) is the main component of the resin composition of this invention. EVOH (A) is a copolymer having ethylene units and vinyl alcohol units as main structural units. EVOH (A) is usually obtained by polymerizing ethylene and vinyl ester and saponifying the resulting ethylene-vinyl ester copolymer.

The ethylene unit content of EVOH (A) (ie, the ratio of the number of ethylene units to the total number of monomer units in EVOH (A)) must be in the range of 15 to 60 mol%. The lower limit of the ethylene unit content of EVOH (A) is preferably 20 mol%, more preferably 23 mol%. On the other hand, the upper limit of the ethylene unit content of EVOH (A) is preferably 55 mol%, more preferably 50 mol%. When the ethylene unit content of EVOH (A) is less than 15 mol %, the gas barrier property under high humidity is lowered, and the melt formability is also deteriorated. Conversely, when the ethylene unit content of EVOH (A) exceeds 60 mol%, sufficient gas barrier properties cannot be obtained.

The degree of saponification of EVOH (A) (ie, the ratio of the number of vinyl alcohol units to the total number of vinyl alcohol units and vinyl ester units in EVOH (A)) must be 85 mol% or more. The lower limit of the degree of saponification of EVOH (A) is preferably 95 mol%, more preferably 99 mol%. On the other hand, the upper limit of the degree of saponification of EVOH (A) is preferably 100 mol%, more preferably 99.99 mol%. When the degree of saponification of EVOH (A) is less than 85 mol%, sufficient gas barrier properties may not be obtained, and furthermore, thermal stability may become insufficient.

When EVOH (A) is composed of a mixture of two or more types of EVOH having different ethylene unit contents, the average value calculated from the mixture mass ratio is regarded as the ethylene unit content. At this time, the difference in ethylene unit content between the EVOHs whose ethylene unit content is the farthest is preferably 30 mol% or less, more preferably 20 mol% or less, and most preferably 15 mol% or less. Similarly, when EVOH (A) is composed of a mixture of two or more types of EVOH having different degrees of saponification, the average value calculated from the mixture mass ratio is regarded as the degree of saponification of the mixture. In this case, the difference in the degree of saponification between the farthest EVOHs is preferably 7% or less, more preferably 5% or less. When it is desired to obtain a resin composition with a higher balance between thermoformability and gas barrier properties, it is preferable to make the blending mass ratio (A-1/A-2) 60/40 to 90/10, Mixed EVOH (A-1) with an ethylene unit content of 24 mol% or more and less than 34 mol%, and a saponification degree of 99 mol% or more, and an ethylene unit content of 34 mol% or more and less than 50 mol% %, EVOH (A-2) with a degree of saponification of 99 mol% or more is used as EVOH (A). The ethylene unit content and saponification degree of EVOH (A) can be obtained by nuclear magnetic resonance (NMR) method.

The melt flow rate of EVOH (A) based on JIS K 7210:2014 (hereinafter, also referred to as "MFR"; temperature 210°C, load 2160g) has a lower limit of usually 0.1g/10min and an upper limit of usually 50g/10min .

EVOH (A) may contain monomer units other than ethylene units, vinyl alcohol units, and vinyl ester units as copolymerized units within the range that does not interfere with the object of the present invention. Examples of the aforementioned monomers include α-olefins such as propylene, 1-butene, isobutylene, 4-methyl-1-pentene, 1-hexene, and 1-octene; Unsaturated carboxylic acids such as acrylic acid, acrylic acid, maleic acid, etc., their salts, their partial or complete esters, their nitriles, their amides, and their anhydrides; vinyltrimethoxysilane, vinyltriethoxysilane, ethylene Vinyl silane compounds such as tris(β-methoxyethoxy)silane, g-methacryloxypropyltrimethoxysilane, etc.; unsaturated sulfonic acid or its salt; unsaturated thiols; Vinylpyrrolidones. The content of monomer units other than ethylene units, vinyl alcohol units and vinyl ester units in EVOH (A) is usually 5 mol% or less, preferably 2 mol% or less, more preferably 1 mol% or less.

The content of EVOH (A) in the resin composition of the present invention is usually at least 70% by mass, preferably at least 80% by mass, more preferably at least 90% by mass. By setting the content of EVOH (A) within this range, the melt moldability of the obtained resin composition is improved, and the molded article obtained therefrom is also excellent in gas barrier properties, oil resistance, and the like.

＜Compound (B)＞ The resin composition of this invention contains the compound (B) represented by following formula (X). The resin composition of the present invention suppresses occurrence of scorch even in repeated melt molding processes by containing a predetermined amount of the compound (B). Although the reason for the suppression of scorch is not clear, it is believed that the compound (B) acts as a lubricant, which reduces the friction between the resin composition and the surface of the screw or die during the melt molding of the resin composition of the present invention, thereby reducing deterioration Resin adhesion and local shear heat generation. In addition, the resin composition of the present invention also improves coloring resistance under alkaline conditions. Although the reason for improving the coloring resistance is not clear, it is considered that the adjacent nitrile groups in the compound (B) interact with the alkali component.

(In formula (X), Z ¹ and Z ² are each independently a hydrogen atom or a methyl group).

The content of the compound (B) in the aforementioned resin composition must be in the range of 5 to 100 ppm. The lower limit of the content of the compound (B) is preferably 10 ppm. On the other hand, the upper limit of the content of compound (B) is preferably 60 ppm. When the content of the compound (B) is less than 5 ppm, the generation of scorch is not sufficiently suppressed in the repeated melt molding process, and the long-term running performance becomes insufficient. On the other hand, when the content of the compound (B) exceeds 100 ppm, the coloring resistance under alkaline conditions may become insufficient and may become a problem. The content of the compound (B) in the resin composition can be obtained by a nuclear magnetic resonance (NMR) method.

＜Metal ion (C)＞ The resin composition of the present invention preferably further contains metal ions (C). Since the resin composition of the present invention contains the metal ion (C), it has excellent interlayer adhesion when it becomes a molded article with a multilayer structure. The reason why interlayer adhesion is increased by metal ions (C) is unknown, but it is estimated that one reason is that when the layer adjacent to EVOH (A) has a molecule having a functional group that can react with the hydroxyl group of EVOH (A), This bond forming reaction is accelerated by the metal ion (C). Moreover, by controlling the content ratio of the metal ion (C) and the carboxylic acid (D) mentioned later, the melt moldability and coloring resistance of the obtained resin composition can be further improved.

The lower limit of the content of the metal ion (C) in the aforementioned resin composition is preferably 100 ppm, more preferably 150 ppm. On the other hand, the upper limit of the content of the metal ion (C) in the aforementioned resin composition is preferably 400 ppm, more preferably 350 ppm. When the content of the metal ion (C) in the aforementioned resin composition is less than 100 ppm, the interlayer adhesion of the obtained multilayer structure may become insufficient. On the other hand, when content of the metal ion (C) in the said resin composition exceeds 400 ppm, coloring resistance may become inadequate.

Examples of the metal ion (C) include alkali metal ions, alkaline earth metal ions, and other transition metal ions, and these may be used alone or in combination of two or more. Among them, the metal ion (C) preferably contains alkali metal ions, more preferably consists of only alkali metal ions. Since the metal ions (C) are composed only of alkali metal ions, not only the simplification of the production method becomes possible, but also the interlayer adhesion of the multilayer structure can be further improved.

Examples of alkali metal ions include lithium, sodium, potassium, rubidium, and cesium ions, but sodium or potassium ions are preferred from the viewpoint of industrial acquisition.

Examples of alkali metal salts that donate alkali metal ions include aliphatic carboxylates, aromatic carboxylates, carbonates, hydrochlorides, nitrates, sulfates, and phosphoric acids of alkali metals such as lithium, sodium, and potassium. Salts, metal complexes. Among these, sodium acetate, potassium acetate, sodium phosphate, and potassium phosphate are more preferable from the viewpoint of easy acquisition.

It may be preferable that the metal ion (C) contains an alkaline earth metal ion. Since the metal ions (C) contain alkaline earth metal ions, thermal degradation of EVOH (A) at the time of recycling trimmings is suppressed, and the occurrence of gel and pitting of molded articles may be suppressed.

Examples of alkaline earth metal ions include beryllium, magnesium, calcium, strontium, and barium ions, but magnesium or calcium ions are preferred from the viewpoint of industrial ease of acquisition.

Examples of alkaline earth metal salts that impart alkaline earth metal ions include aliphatic carboxylates, aromatic carboxylates, carbonates, hydrochlorides, nitrates, sulfates, Phosphates, metal complexes.

＜Carboxylic acid (D)＞ It is preferable that the resin composition of this invention further contains the carboxylic acid (D) whose pKa is in the range of 3.5-5.5. By containing the carboxylic acid (D), the resin composition of the present invention can further improve the melt moldability of the resin composition or the coloring resistance at high temperature. In particular, since the pKa of the carboxylic acid (D) is in the range of 3.5 to 5.5, the pH buffering ability of the obtained resin composition is increased, and the coloring caused by acidic substances or alkaline substances may be further improved.

The lower limit of the content of the carboxylic acid (D) in the aforementioned resin composition is preferably 50 ppm, more preferably 100 ppm. On the other hand, the upper limit of the content of the carboxylic acid (D) in the aforementioned resin composition is preferably 400 ppm, more preferably 350 ppm. When the content of the carboxylic acid (D) in the resin composition is less than 50 ppm, the coloring resistance at high temperature may become insufficient. On the other hand, when the content of the carboxylic acid (D) in the aforementioned resin composition exceeds 400 ppm, melt moldability may become insufficient or odor may become a problem. The content of carboxylic acid (D) was determined by titrating the obtained extract after extracting 10 g of the aforementioned resin composition with 50 ml of pure water at 95° C. for 8 hours. Here, the carboxylic acid which exists as a salt in the said extract liquid is not considered as content of the carboxylic acid (D) in the said resin composition.

Examples of the carboxylic acid (D) include monocarboxylic acids and polycarboxylic acids, and these may be used alone or in combination of two or more. When the said resin composition contains both a monocarboxylic acid and a polyhydric carboxylic acid as a carboxylic acid (D), melt moldability and coloring resistance at high temperature may be remarkably improved. Moreover, polyhydric carboxylic acid may have 3 or more carboxyl groups. In this case, the coloring resistance of the resin composition of the present invention may be more effectively improved.

The so-called monocarboxylic acid is a compound having one carboxyl group in the molecule. The monocarboxylic acid having a pKa in the range of 3.5 to 5.5 is not particularly limited, for example, formic acid (pKa=3.77), acetic acid (pKa=4.76), propionic acid (pKa=4.85), butyric acid (pKa= 4.82), caproic acid (pKa=4.88), capric acid (pKa=4.90), lactic acid (pKa=3.86), acrylic acid (pKa=4.25), methacrylic acid (pKa=4.65), benzoic acid (pKa=4.20), 2-naphthoic acid (pKa=4.17), etc. These carboxylic acids may further have a substituent of a hydroxyl group, an amino group, or a halogen atom as long as the pKa is in the range of 3.5 to 5.5. Among these, acetic acid is preferable in terms of high safety and ease of handling.

The so-called polycarboxylic acid is a compound having two or more carboxyl groups in the molecule. In this case, the pKa of at least one carboxyl group should be in the range of 3.5 to 5.5, for example, oxalic acid (pKa ₂ =4.27), succinic acid (pKa ₁ =4.20), fumaric acid (pKa ₂ =4.44), Malic acid (pKa ₂ =5.13), glutaric acid (pKa ₁ =4.30, pKa ₂ =5.40), adipic acid (pKa ₁ =4.43, pKa ₂ =5.41), pimelic acid (pKa ₁ =4.71), ortho Phthalic acid (pKa ₂ =5.41), isophthalic acid (pKa ₂ =4.46), terephthalic acid (pKa ₁ =3.51, pKa ₂ =4.82), citric acid (pKa ₂ =4.75), tartaric acid (pKa ₂ =4.40), glutamic acid (pKa ₂ =4.07), aspartic acid (pKa=3.90), etc.

＜Other ingredients＞ The resin composition of this invention may contain other components within the range which does not impair the effect of this invention. Examples of other components include phosphoric acid compounds, boron compounds, thermoplastic resins other than EVOH (A), crosslinking agents, desiccants, oxidation accelerators, antioxidants, oxygen absorbers, plasticizers, lubricants, and heat stabilizers (melt stabilizers), processing aids, surfactants, deodorizers, antistatic agents, ultraviolet absorbers, antifogging agents, flame retardants, pigments, dyes, fillers, fillers, reinforcing agents for various fibers, etc. .

＜Phosphoric acid compound＞ When a phosphoric acid compound is contained, the lower limit of the content in the resin composition is preferably 1 ppm in terms of phosphate radicals, more preferably 10 ppm. On the other hand, the upper limit of the content of the phosphoric acid compound in the resin composition is preferably 200 ppm, more preferably 100 ppm in terms of phosphate radicals. By containing the phosphoric acid compound within this range, the thermal stability of the aforementioned resin composition can be improved. In particular, it may be possible to suppress the occurrence of gel pitting or coloration when melt molding is performed for a long period of time.

As said phosphoric acid compound, various acids, such as phosphoric acid and phosphorous acid, or salts thereof, etc. can be used, for example. The phosphate system may be any one of the first phosphate, the second phosphate, and the third phosphate. The cationic species of the phosphate is not particularly limited, but the cationic species is preferably an alkali metal or an alkaline earth metal. Among them, sodium dihydrogenphosphate, potassium dihydrogenphosphate, disodium hydrogenphosphate, and dipotassium hydrogenphosphate are preferable as the phosphoric acid compound.

＜Boron compounds＞ When a boron compound is contained, the lower limit of the content in the aforementioned resin composition is preferably 5 ppm in terms of boron element, more preferably 10 ppm. On the other hand, the upper limit of the content in the aforementioned resin composition is preferably 1000 ppm, more preferably 500 ppm in terms of boron element. By containing the boron compound within this range, the thermal stability of the resin composition during melt molding may be improved, and the occurrence of gel pitting may be suppressed. In addition, there are cases where the mechanical properties of the obtained molded body are improved. These effects are presumed to be due to the chelation interaction between EVOH(A) and boron compounds.

Examples of the boron compound include boric acid, boric acid esters, borate salts, and boron hydride. Specifically, examples of boric acid include orthoboric acid (H ₃ BO ₃ ), metaboric acid, and tetraboric acid, examples of boric acid esters include trimethyl borate and triethyl borate, examples of borates include Examples thereof include alkali metal salts or alkaline earth metal salts of the aforementioned boric acid, borax, and the like. Among these, orthoboric acid is preferred.

Examples of thermoplastic resins other than EVOH (A) include various polyolefins (polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene-propylene copolymer, ethylene and carbon Copolymers of α-olefins, polyolefins and maleic anhydride copolymers, ethylene-vinyl ester copolymers, ethylene-acrylic acid ester copolymers, or those grafted with unsaturated carboxylic acids or their derivatives modified polyolefin, etc.), various polyamides (nylon 6, nylon 6.6, nylon 6/66 copolymer, nylon 11, nylon 12, polym-xylylene adipamide, etc.), various polyesters (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), polyvinyl chloride, polyvinylidene chloride, polystyrene, polyacrylonitrile, polyamine-based Formate, polycarbonate, polyacetal, polyacrylate and modified polyvinyl alcohol resin, etc. The content of the aforementioned thermoplastic resin in the aforementioned resin composition is usually less than 30% by mass, preferably less than 20% by mass, more preferably less than 10% by mass.

＜Manufacturing method of resin composition＞ As the method for producing the resin composition of the present invention, as long as it is a method that can uniformly mix the compound (B) in the EVOH (A) so that the final obtained resin composition contains 5 to 100 ppm of the compound (B), there is no special restrictions. As a preferable production method, a method including the steps of: copolymerizing ethylene and vinyl ester to obtain an ethylene-vinyl ester copolymer (I), saponifying the ethylene-vinyl ester copolymer to obtain Saponification step (II) to obtain EVOH (A), granulation step (III) to obtain water-containing granules of EVOH (A) by granulation operation, and drying the water-containing granules to obtain a resin composition containing EVOH (A) The drying step (IV), after the copolymerization step (I), comprises a mixing step of mixing the ethylene-vinyl ester copolymer or EVOH (A) with the compound (B). At this time, by adjusting the amount of the compound (B) added in the aforementioned mixing step, the content of the compound (B) in the finally obtained resin composition can be easily controlled. In addition, a cleaning operation for removing the compound (B) may be performed as necessary. The adjustment of the content of compound (B) caused by the cleaning operation can be achieved by adjusting the paste concentration and temperature when the paste of EVOH (A) is precipitated in the granulation step (III), the composition and temperature of the coagulation bath, or In the subsequent step, the kind of solution, temperature, time and frequency of immersion of the water-containing particles of EVOH (A) are appropriately adjusted and carried out. Also, by adding a weak solvent little by little to a solution in which the dried resin composition is dissolved in a good solvent, the resin composition is precipitated and recovered, and the compound (B) in the resin composition is recovered. It is also an effective method to adjust the content of the compound (B) by reducing the content of the compound (B) to a necessary amount.

As a mixing step of adding compound (B) to EVOH (A) after the copolymerization step (I), for example, a method of adding compound (B) during saponification reaction or thereafter, in making EVOH (A) The method of impregnating the compound (B) in the strands (strand) precipitated in the step of extracting the paste, the method of cutting the strands separated out, and impregnating the compound (B) in the dried EVOH (A) The method of adding the compound (B) to the re-dissolving of the crushed material, the method of melting and kneading the two components of EVOH (A) and compound (B), and mixing the compound (B) from the extruder ) as a powder, solution or dispersion fed to the melt of EVOH (A) for melt kneading, the compound (B) is blended into a part of EVOH (A) at a high concentration to make a granulated Masterbatch, method of melt-kneading after dry-blending the masterbatch and EVOH (A), etc.

Among them, from the viewpoint of uniformly dispersing a small amount of compound (B) in EVOH (A), as a mixing step of adding compound (B) to EVOH (A), it is preferable to A method of adding compound (B) to EVOH (A) after the reaction. Specifically, compound (B) is added to a solution in which EVOH (A) obtained in the saponification step is dissolved in a good solvent such as a water/methanol mixed solvent, and the mixed solution is extruded from a nozzle or the like into a poor solvent, The precipitated strands are cut to obtain water-containing particles, washed if necessary, and then dried to obtain particles of a resin composition in which EVOH (A) is uniformly mixed with compound (B).

As a method of making the resin composition of the present invention contain components other than the compound (B), for example, mixing pellets of the above-mentioned resin composition in which the compound (B) is mixed with EVOH (A) is mixed with each component, The method of melt-kneading is a method of mixing the components simultaneously with EVOH (A) and the compound (B) when preparing the pellets of the above-mentioned resin composition. The pellets of the above-mentioned resin composition are immersed in a solution containing the components. method etc. At this time, as the particles of the above-mentioned resin composition, both water-containing particles and dry particles can be used.

＜Copolymerization step (I)＞ In addition to the copolymerization step of ethylene and vinyl ester, the copolymerization step may include adding a polymerization inhibitor if necessary, followed by removing unreacted ethylene and unreacted vinyl ester to obtain an ethylene-vinyl ester copolymer solution. Examples of the copolymerization method of ethylene and vinyl ester include well-known methods such as solution polymerization, suspension polymerization, emulsion polymerization, and bulk polymerization. Vinyl acetate is mentioned as a representative vinyl ester used in the polymerization, but other aliphatic vinyl esters such as vinyl propionate or trimethylvinyl acetate can also be used. In addition, a copolymerizable monomer may be copolymerized in a small amount. The polymerization temperature is preferably from 20 to 90°C, more preferably from 40 to 70°C. The polymerization time is preferably from 2 to 15 hours, more preferably from 3 to 11 hours. The polymerization rate is preferably from 10 to 90%, more preferably from 30 to 80%, based on the vinyl ester added. The resin content in the solution after polymerization is preferably from 5 to 85% by mass, more preferably from 20 to 70% by mass.

The initiator used in the copolymerization step (I) is not particularly limited, but an azonitrile-based polymerization initiator is preferably used. The generation rate of free radicals and the solubility in solvents can be controlled by the molecular skeleton of the azonitrile-based polymerization initiator. In addition, the azonitrile-based polymerization initiator is not easily decomposed by metal contact, and is not easily affected by solvents during decomposition. Therefore, by using the azonitrile-based polymerization initiator, the polymerization step can be performed safely and stably. Examples of the azonitrile-based polymerization initiator include 4,4'-azobis(4-cyanovaleric acid), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-Azobis(2-methylbutyronitrile), 2,2'-Azobis(isobutyronitrile), 2,2'-Azobis(2,4-Dimethylvaleronitrile) , 2,2'-Azobis(4-methoxy-2,4-dimethylvaleronitrile). Among these, 2,2'-azobis(2,4-dimethylvaleronitrile) and 2,2'-azobis Nitrobis(4-methoxy-2,4-dimethylvaleronitrile).

＜Saponification step (II)＞ Next, an alkali catalyst is added to the ethylene-vinyl ester copolymer solution, and the copolymer in the solution is saponified to obtain EVOH (A). As a saponification method, any one of a continuous method and a batch method can be employed. Examples of the alkali catalyst include sodium hydroxide, potassium hydroxide, and alkali metal alkoxides. Also, after the saponification step, it is common to add an acid such as acetic acid to neutralize the remaining alkali catalyst.

＜Granulation step (III)＞ As the granulation operation, for example, (1) extruding the solution of EVOH (A) into a low-temperature weak solvent to precipitate or solidify, and then cutting immediately after or after further cooling and solidifying Method, (2) A method of cutting the aqueous resin composition of EVOH (A) after contacting the solution of EVOH (A) with water vapor to obtain the aqueous resin composition of EVOH (A). The water content in the water-containing granules of EVOH (A) obtained by such methods is preferably 50 to 200 parts by mass, more preferably 70 to 150 parts by mass, relative to 100 parts by mass of EVOH (A).

＜Drying step (IV)＞ Preferably, dry granules of EVOH (A) are obtained by drying the aqueous granules of EVOH (A) obtained in the granulation step. The water content in the dry granules is preferably at most 1.0 parts by mass, more preferably at most 0.5 parts by mass, and most preferably at most 0.3 parts by mass, based on 100 parts by mass of EVOH (A) for the purpose of preventing voids and other troubles during molding. Parts by mass or less. As a drying method of the water-containing granule, static drying or flow drying is mentioned, for example. These drying methods may be used alone or in combination. The drying treatment can be carried out by either continuous method or batch method. When combining plural drying methods, continuous or batch methods can be freely selected for each drying method. Drying under a low oxygen concentration or an oxygen-free state is also preferable at the point of reducing deterioration of the resin composition caused by oxygen during drying.

＜Molded body＞ Molding system comprising the resin composition of the present invention is a suitable embodiment of the present invention. The resin composition of the present invention can also be a molded article with a single-layer structure, or a molded article with a multilayer structure having a layer made of the resin composition and other layers, that is, a multilayer structure. Examples of molding methods include extrusion molding, thermoforming, profile molding, hollow molding, rotational molding, and injection molding. The use of the molded article of the present invention involves various aspects, and films, sheets, containers, bottles, tanks, pipes, hoses, etc. can be exemplified as suitable ones.

As a specific molding method, the following methods can be illustrated. In the case of films, sheets, tubes, hoses, etc., it can be obtained by extrusion. If it is in the shape of a container, it can be obtained by injection molding. If it is a hollow container such as a bottle or a barrel, it can be obtained by hollow forming or rotational forming. Examples of hollow molding include extrusion hollow molding in which a parison is obtained by extrusion molding and then blow molded to form it, and injection molding in which a preform is formed by injection molding and then blow molded to form it. Hollow formed. As a method for forming flexible packaging materials or containers, it is preferable to use a method of obtaining packaging materials such as multilayer films by extrusion molding, and thermoforming the multilayer sheets obtained by extrusion molding to form container-shaped packaging materials. method.

＜Multilayer structure＞ A more suitable embodiment of the present invention is a layer structure system including a layer composed of the resin composition of the present invention. The multi-layer structure system is formed by laminating layers made of the resin composition of the present invention and other layers. As another layer other than the aforementioned resin composition layer, a layer made of a resin other than EVOH (A) is preferable. Moreover, the said multilayer structure may further have the layer which consists of adhesive resins. As the layer composition of this multilayer structure, if the layer made of resin other than EVOH (A) is regarded as x layer, the resin composition layer of the present invention is regarded as y layer, and the adhesive resin layer is regarded as z layer, then for example x/y, x/y/x, x/z/y, x/z/y/z/x, x/y/x/y/x, x/z/y/z/x /z/y/z/x etc. When plural x-layers, y-layers, and z-layers are provided, their types may be the same or different. In addition, a layer using recycled resin from scraps such as trimmings generated during molding may be provided separately, or the recycled resin may be blended into a layer made of resin other than EVOH (A). The thickness and composition of each layer of the multilayer structure are not particularly limited, but from the viewpoint of formability and cost, the thickness ratio of the y layer to the total layer thickness is usually 2 to 20%.

The resin used for the x layer is preferably a thermoplastic resin from the viewpoint of processability and the like. Examples of thermoplastic resins include various polyolefins (polyethylene, polypropylene, poly1-butene, poly4-methyl-1-pentene, ethylene-propylene copolymer, ethylene and a- Copolymers of olefins, copolymers of polyolefins and maleic anhydride, ethylene-vinyl ester copolymers, ethylene-acrylate copolymers, or modified polymers grafted with unsaturated carboxylic acids or their derivatives Olefin, etc.), various polyamides (nylon 6, nylon 6.6, nylon 6/66 copolymer, nylon 11, nylon 12, polym-xylylene adipamide, etc.), various polyesters (polyterephthalic acid Ethylene glycol, polybutylene terephthalate, polyethylene naphthalate, etc.), polyvinyl chloride, polyvinylidene chloride, polystyrene, polyacrylonitrile, polyurethane, polycarbonate Esters, polyacetals, polyacrylates and modified polyvinyl alcohol resins. Such a thermoplastic resin layer may be unstretched, or may be uniaxially or biaxially stretched or calendered. Among these thermoplastic resins, polyolefin is preferable in terms of moisture resistance, mechanical properties, economy, and heat sealability, and polyamide or polyester is preferred in terms of mechanical properties, heat resistance, etc. more appropriate.

The adhesive resin used for the aforementioned z-layer is not particularly limited as long as it can adhere to each layer, and polyurethane-based or polyester-based one-component or two-component curable adhesives, Carboxylic acid modified polyolefin, etc. Carboxylic acid modified polyolefin is a polyolefin copolymer containing unsaturated carboxylic acid or its anhydride (maleic anhydride, etc.) as a copolymerization component; or, it is obtained by grafting unsaturated carboxylic acid or its anhydride on polyolefin graft copolymer.

Examples of methods for obtaining the multilayer structure of the present invention include coextrusion molding, coextrusion hollow molding, coinjection molding, extrusion lamination, coextrusion lamination, dry lamination, and solution coating. Furthermore, for the multilayer structure obtained by such a method, by further vacuum or air pressure deep drawing, blow molding, press molding, etc., after reheating in the range below the melting point of EVOH (A), After secondary processing and forming, it can become the target forming body. In addition, for the multilayer structure, uniaxial or biaxial stretching may be carried out after reheating in the range below the melting point of EVOH (A) by roll stretching method, scaling stretching method, inflation stretching method, etc. An extended multilayer construct is obtained.

The resin composition of the present invention suppresses the occurrence of scorch even in repeated melt molding procedures, and is also excellent in coloring resistance under alkaline conditions. Also, the resin composition of the present invention can be provided economically. Therefore, the resin composition of the present invention can be formed into films, sheets, containers, etc., and is suitable for various packaging materials. A packaging material having a molded body containing the resin composition of the present invention is a suitable embodiment of the present invention. [Example]

Hereinafter, the present invention will be specifically described by means of examples, but the present invention is not limited by these examples at all. In addition, each analysis and evaluation in this Example was performed by the following method.

(1) Ethylene unit content and saponification degree of EVOH(A) ₆ ) was measured at 80°C using 500 MHz ¹ H-NMR (manufactured by JEOL Ltd.: "GX-500"), and obtained from the peak intensity ratios of ethylene units, vinyl alcohol units, and vinyl ester units. Ethylene unit content and saponification degree.

(2) Content of Compound (B) Dissolve the dried pellets in DMSO-d ₆ containing TMS as an internal standard substance, and use ¹ H-NMR at 500 MHz (manufactured by JEOL Ltd.: "GX-500"). Measured at 45°C, from the ratio of the peak intensity of the ethylene unit, vinyl alcohol unit, vinyl ester unit to the peak intensity of the methyl hydrogen of the methoxy group or the methylene hydrogen of the ethoxy group in the compound (B), find Show the content of compound (B). In addition, the peak of the methyl hydrogen of the methoxy group or the methylene hydrogen of the ethoxy group which the compound (B) has was detected around 3.13 ppm.

(3) Content of metal ions (C) 0.5 g of the dry granules were placed in a pressure vessel made of Teflon (registered trademark), 5 mL of concentrated nitric acid was added thereto, and the mixture was decomposed at room temperature for 30 minutes. After decomposing, put the lid on the aforementioned container, heat at 150°C for 10 minutes, and then heat at 180°C for 5 minutes with a wet-type decomposition device to further decompose, then cool down to room temperature, and transfer the treated liquid To a 50mL measuring bottle, adjust the volume with pure water. The solution was measured by an ICP emission spectrometer, and the content of each metal ion in the dry particles was quantified. Furthermore, the content of phosphoric acid compound and boron compound can also be quantified by the same method.

(4) Content of carboxylic acid (D) Put 10 g of dry granules and 50 mL of pure water into a 100 mL Erlenmeyer flask with a stopper, install a cooling condenser, and stir at 95° C. for 8 hours. After cooling the obtained extract to 20° C., the content of carboxylic acid (D) was quantified by titrating with 0.02 mol/L aqueous sodium hydroxide solution using phenolphthalein as an indicator.

(5) pH of the extract Put 10 g of dry granules and 50 mL of pure water into a 100 mL Erlenmeyer flask with a stopper, install a cooling condenser, and stir at 95° C. for 8 hours. The obtained extract was cooled to 20°C, and the pH was measured.

(6) Evaluation of scorched black Use 2 kg of dry granules to granulate with a single-screw extruder (D2020 from Toyo Seiki Co., Ltd., caliber 20 mmφ, L/D20, full-flight screw), to obtain granules that have been melt-molded once. The temperature conditions were supply part/compression part/measurement part/die=175/215/225/220° C., and the number of rotations of the screw was 50 rpm. The obtained melt-molded pellets were granulated again under the same conditions to obtain pellets melt-molded twice. After repeating the granulation five times in the same manner, it was rinsed (cleaned) in a single-screw extruder with 500 g of high-density polyethylene. Next, the screw was pulled out, and after visually checking the adhesion state of charred black on the screw, it was collected, weighed, and evaluated on the basis of the following A to D, which was used as an evaluation index of charred black. A: The color of burnt black is light yellow, and its amount is less than 0.1g B: The color of scorched black is yellow or brown, and the amount is less than 0.1g C: The color of scorched black is yellow or brown, and the amount is more than 0.1g and less than 0.3g D: The color of burnt black is yellow or brown, and the amount is 0.3 g or more

(7) coloring resistance 100 g of the dried granules were immersed in 1000 g of a 0.1 mol/liter sodium hydroxide aqueous solution, the lid of the container containing the granules was covered, and the mixture was left to stand at 80° C. for 1 week. Using "LabScan XE Sensor" manufactured by HunterLab, the YI (yellow index) value of the pellets before and after immersion was measured, and the increase in YI due to immersion was determined. Evaluation was performed on the basis of the following A to D criteria. This evaluation result was regarded as the indicator of the coloring resistance of the resin composition under alkaline conditions. Furthermore, the YI value represents an index of the yellowness (yellowness value) of the object. The higher the YI value, the stronger the yellowness. On the other hand, the lower the YI value, the weaker the yellowness, indicating less coloring. A: The increase of YI is less than 2 B: The increase of YI is more than 2 but less than 4 C: The increase of YI is more than 4 but less than 6 D: The increase of YI is more than 6

(8) Appearance characteristics after melt molding Use 10 g of dried pellets, heat and melt at 220°C for 6 minutes with a heating compression press to prepare a disk-shaped sample with a thickness of 3 mm. The YI value of the obtained disc-shaped sample was measured using "LabScan XE Sensor" manufactured by HunterLab, and evaluated on the basis of the following A to D criteria. This evaluation result was taken as an index of the appearance characteristic after melt molding. A: YI is less than 8 B: YI is 8 or more and less than 13 C: YI is more than 13 and less than 20 D: YI is 20 or more

(9) Interlayer connectivity Use dry particles, linear low-density polyethylene (Novatec LL-UF943 manufactured by Japan Polyethylene Corporation, hereinafter referred to as LLDPE) and adhesive resin (Bynel CXA417E10 manufactured by DuPont diluted to 7% by the above LLDPE, hereinafter referred to as Ad), Three kinds of 5-layer multilayer films (LLDPE/Ad/EVOH/Ad/LLDPE=50μm/10μm/10μm/10μm/50μm) were produced. The extruder, extrusion conditions, and the die used are as follows. Extrusion machine: EVOH: Single-screw extrusion machine (Toyo Seiki Co., Ltd. experimental machine ME type CO-EXT) Diameter 20mmφ, L/D20, full thread screw Supply section/compression section/measurement section/die head=175/210/220/220°C LLDPE: Uniaxial Extrusion Machine (GT-32-A, PLASTIC Engineering Research Institute Co., Ltd.) Diameter 32mmφ, L/D28, fully threaded screw Supply section/compression section/measurement section/die head=150/200/210/220°C Ad: Single-screw extrusion machine (TECHNOVEL SZW20GT-20MG-STD Co., Ltd.) Diameter 20mmφ, L/D20, full thread screw Supply part/compression part/measurement part/die head=150/200/220/220℃ Dies: 3 types of 300mm width hanger type dies for 5 layers (manufactured by PLASTIC Engineering Research Institute Co., Ltd.)

After starting the above-mentioned film production, the obtained multilayer film was conditioned for 15 minutes at a temperature of 23°C and a relative humidity of 50%RH, and then cut out a sample with a length of 150 mm and a width of 15 mm along the extrusion direction. Using the Autograph DCS-50M tensile testing machine manufactured by Shimadzu Corporation, the peel strength of the above-mentioned samples was measured (23°C, 50%RH environment, tensile speed 250mm/min, T-peel mode), using the following A ~ C criteria for evaluation. Take this evaluation result as an indicator of indirect effort. A: More than 500g/15mm B: More than 300g/15mm and less than 500g/15mm C: Less than 300g/15mm

[Synthesis Example 1] Polymerization of ethylene-vinyl acetate copolymer was carried out under the following raw materials and conditions using a 250 L pressurized reaction tank. ・Vinyl acetate: 105.0 kg ・Methanol: 38.3kg ・Initiator: 2,2'-azobis(2,4-dimethylvaleronitrile) (10.0g/L methanol solution), initial supply volume: 2440mL, continuous supply volume: none ・Polymerization temperature: 60℃ ・Polymerization tank ethylene pressure: 3.7MPa

When the polymerization rate of vinyl acetate reached about 40%, sorbic acid was added, and the polymerization was stopped by cooling. Next, after the reaction tank is opened to remove vinyl, it is supplied to the ejection tower, and unreacted vinyl acetate is removed from the top of the tower by introducing methanol vapor from the lower part of the tower to obtain a methanol solution of ethylene-vinyl acetate copolymer . Add this solution to the saponification reactor, and add sodium hydroxide/methanol solution (80 g/L) in such a way that the molar ratio of sodium hydroxide to the vinyl ester unit in the copolymer becomes 0.7, and add methanol to reduce the concentration of the copolymer to 0.7. Adjusted to 15%. The temperature of this solution was raised to 60° C., and the saponification reaction was carried out for about 4 hours while nitrogen gas was blown into the reactor. Then, acetic acid and water were added to the reaction solution to stop the saponification reaction, and the EVOH suspension was obtained, which was then deliquored by a centrifuge. After adding acetonitrile to the obtained EVOH so that the molar ratio of acetonitrile to all the monomer units in the EVOH becomes 2, the dehydration operation was repeated twice. Furthermore, a large amount of water was added to the aforementioned EVOH, and the dehydration operation was repeated. Next, by drying at 60° C. for 24 hours, a rough dry product of EVOH having an ethylene unit content of 32 mol % and a degree of saponification of 99.9 mol % was obtained.

[Synthesis Example 2] Except that the conditions for the polymerization of the above-mentioned ethylene-vinyl acetate copolymer were changed to the following, by the same operation as in Synthesis Example 1, a crude product of EVOH with an ethylene unit content of 32 mol% and a degree of saponification of 99.9 mol% was obtained. dry matter. ・Vinyl acetate: 83.0 kg ・Methanol: 26.6kg ・Initiator: 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (2.5g/L methanol solution), initial supply volume: 362mL, continuous supply volume: 1120mL /hr ・Polymerization temperature: 60℃ ・Polymerization tank ethylene pressure: 3.6MPa

[Synthesis Example 3] Except that the conditions during the polymerization of the aforementioned ethylene-vinyl acetate copolymer were changed to the following, by the same operation as in Synthesis Example 1, crude EVOH with an ethylene unit content of 44 mol% and a degree of saponification of 99.9 mol% was obtained. dry matter. ・Vinyl acetate: 76.7 kg ・Methanol: 11.0kg ・Initiator: 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (2.5g/L methanol solution), initial supply volume: 510mL, continuous supply volume: 1570mL /hr ・Polymerization temperature: 60℃ ・Polymerization tank ethylene pressure: 5.5MPa

[Examples 1 to 9 and Comparative Examples 1 to 5] Put the rough dry product of EVOH obtained in Synthesis Example 1 above into a mixture of water/methanol=40/60 (mass ratio) so that the solid content becomes 40%. In the solvent, it stirred and dissolved at 60 degreeC for 6 hours. Add the compound (B) in which Z ¹ and Z ² are hydrogen atoms in the above formula (X) to the obtained solution, and after stirring for 1 hour, continuously extrude water adjusted to 0°C from a nozzle with a diameter of 4mm /methanol=90/10 (mass ratio) in the precipitation bath, make it precipitate into strands. This strand is introduced into a granulator to obtain porous water-containing granules. After washing the water-containing particles with an aqueous acetic acid solution and ion-exchanged water, an immersion treatment was performed with an aqueous solution containing sodium acetate and acetic acid. The aqueous solution and the water-containing granules were separated and deliquified, then placed in a hot air dryer, dried at 80° C. for 3 hours, and then dried at 110° C. for 35 hours to obtain dry granules. Using the dried pellets, the above-mentioned analysis and evaluation were carried out. Furthermore, the resin composition of the composition described in Table 1 was manufactured by adjusting the addition amount of compound (B) and the density|concentration of each component of the aqueous solution for immersion treatment.

[Example 10] Except having used potassium acetate instead of sodium acetate, dry granules were manufactured by the same operation as Example 1, and analysis and evaluation were performed.

[Example 11] Except having used sodium lactate instead of sodium acetate, and lactic acid instead of acetic acid, dry granules were produced by the same operation as Example 1, and analysis and evaluation were performed.

[Example 12] Except having used sodium trifluoroacetate instead of sodium acetate and trifluoroacetic acid instead of acetic acid, dry particles were produced in the same manner as in Example 1, and analyzed and evaluated.

[Example 13] Except for using the roughly dried product of EVOH obtained in Synthesis Example 2 above, dry particles were produced in the same manner as in Example 1, and analyzed and evaluated.

[Example 14] Except using the rough dry product of EVOH obtained in Synthesis Example 3 above, and using a mixed solvent of water/methanol=25/75 (mass ratio) during dissolution, dry particles were produced and analyzed by the same operation as in Example 1 and evaluation.

Table 1 shows the composition and evaluation results of each resin composition in Examples and Comparative Examples.

Claims (7)

A method for producing a resin composition, which is a method for producing a resin composition comprising an ethylene-vinyl alcohol copolymer (A) and a compound (B) represented by the following formula (X), characterized in that it comprises ethylene-vinyl alcohol copolymer (A) Saponification of the vinyl ester copolymer to obtain the saponification step (II) of the ethylene-vinyl alcohol copolymer (A), and adding the compound (B) to the ethylene-vinyl alcohol copolymer (A) after the saponification step (II) In the mixing step, the content of ethylene units in the ethylene-vinyl alcohol copolymer (A) is 15-60 mol%, the degree of saponification is 85 mol% or more, and the content of the compound (B) in the aforementioned resin composition is 5-100ppm ;

(In formula (X), Z ¹ and Z ² are each independently a hydrogen atom or a methyl group). A method for producing a resin composition as claimed in claim 1, which comprises the step (I) of copolymerizing ethylene and vinyl ester to obtain an ethylene-vinyl ester copolymer, saponifying the aforementioned ethylene-vinyl ester copolymer to obtain ethylene-ethylene The saponification step (II) of the alcohol copolymer (A), the granulation step (III) of the water-containing granules of the ethylene-vinyl alcohol copolymer (A) obtained by the granulation operation, and the drying of the water-containing granules to obtain a drying step (IV) of particles of a resin composition containing ethylene-vinyl alcohol copolymer (A), and A mixing step comprising adding the compound (B) to the ethylene-vinyl alcohol copolymer (A) after the saponification step (II) is included. The method for producing a resin composition as claimed in item 1 or 2, wherein the aforementioned mixing step includes adding compound (B), and extrude the mixed solution from a nozzle into a weak solvent, cut the precipitated strands to obtain the granulation step (III) of water-containing particles, dry the aforementioned water-containing particles to obtain ethylene-ethylene-containing The step (IV) of drying the pellets of the resin composition in which the compound (B) is mixed with the base alcohol copolymer (A). The manufacturing method of the resin composition as claimed in item 1 or 2, wherein the pH of the extract obtained by extracting 10 g of the aforementioned resin composition with 50 ml of pure water at 95° C. for 8 hours at 20° C. is in the range of 4.0 to 5.5. The method for producing a resin composition according to claim 1 or 2, wherein the aforementioned resin composition further contains 100-400 ppm of metal ions (C). The method for producing a resin composition according to claim 1 or 2, wherein the resin composition further contains 50 to 400 ppm of carboxylic acid (D) with a pKa in the range of 3.5 to 5.5. A method of manufacturing a molded body comprising the aforementioned resin composition, which is to shape the aforementioned resin composition after obtaining the aforementioned resin composition by the manufacturing method of the resin composition according to any one of claims 1 to 6 .