JP7079270B2 - Method for Producing Ethylene-Vinyl Alcohol Copolymer-Containing Resin Composition - Google Patents

Description

The present invention relates to a resin composition containing an ethylene-vinyl alcohol copolymer as a main component, and a molded product and a packaging material using the resin composition.

Since the ethylene-vinyl alcohol copolymer (hereinafter referred to as "EVOH") has excellent gas barrier properties and melt moldability, it can be molded into films, sheets, pipes, tubes, bottles, etc. by various melt molding methods. It is widely used as a packaging material in the food and industrial fields where gas barrier properties are required. However, when EVOH is continuously melt-molded for a long time, the generation of kogation in the extruder cylinder, screw and die may become a problem. The generation of such kogation not only destabilizes the melt molding process, but also leads to deterioration of the quality such as the appearance and mechanical properties of the obtained molded product. Therefore, the operation is periodically stopped to disassemble the extruder. It was necessary to carry out cleaning. As a result, material loss has also occurred due to an increase in manufacturing costs and the suspension and restart of the extruder operation. Therefore, improvement of the problem of koge is required.

Various EVOH-containing resin compositions have been developed to improve the above problems. For example, Patent Document 1 describes a resin composition containing EVOH, a boron compound, sodium acetate and magnesium acetate. Then, according to the resin composition, it is described that the long-running property at the time of melt molding is improved. Patent Document 2 describes a resin composition containing EVOH and a conjugated polyene compound. Then, according to the resin composition, it is described that the generation of gels and lumps due to melt molding is suppressed. Patent Document 3 describes a resin composition containing EVOH, a specific carboxylic acid metal salt, and a hindered phenolic antioxidant. It is described that the resin composition has excellent thermal stability and suppresses the formation of an oxidizing gel at high temperatures. Patent Document 4 describes a resin composition containing EVOH and a specific unsaturated aldehyde. According to the resin composition, it is described that the generation of defects such as fish eyes and gel due to melt molding is suppressed, and the long-running property at the time of melt molding is improved.

Japanese Unexamined Patent Publication No. 11-60874 Japanese Unexamined Patent Publication No. 9-71620 Japanese Unexamined Patent Publication No. 4-227744 International Publication No. 2013/146961

On the other hand, it is widely practiced to recover trims and burrs generated during the production of melt-molded products, crush and melt them again, and use them. We have found that there is a problem that kogation occurs when the heat history is received. In recent years, the contents packaged using packaging materials have become more and more diversified, and the packaging materials are required to be particularly stable against acidic substances and basic substances. However, the present inventors have found that the above-mentioned EVOH-containing resin composition has a problem that it is easily colored under basic conditions, particularly high temperature conditions.

The present invention has been made based on the above circumstances, and an object thereof is to obtain EVOH which suppresses the generation of kogation even in a repeated melt molding process and has excellent color resistance under basic conditions. There is something in it.

As a result of diligent studies to solve the above problems, the present inventors have made a resin composition containing EVOH as a main component contain a compound having a specific structure, so that the koge can be formed even in a repeated melt molding process. It was found that the occurrence can be suppressed. Further, they have found that by controlling the content of the compound in an appropriate range, the generation of kogation is suppressed and the coloring resistance under basic conditions is also improved, which led to the present invention. The above problem is solved by the following invention.

(1) A resin composition containing an ethylene-vinyl alcohol copolymer (A) and a compound (B) represented by the following formula (X), wherein the ethylene unit content of the ethylene-vinyl alcohol copolymer (A) is high. Is 15 to 60 mol%, the saponification degree is 85 mol% or more, and the content of the compound (B) is 5 to 100 ppm.

(In formula (X), Z ¹ and Z ² are independently hydrogen atoms or methyl groups, respectively.)
(2) The resin according to (1), wherein the pH of the extract obtained by extracting 10 g of the resin composition with 50 ml of pure water at 95 ° C. for 8 hours is in the range of 4.0 to 5.5 at 20 ° C. Composition.
(3) The resin composition according to (1) or (2), further containing 100 to 400 ppm of a metal ion (C).
(4) The resin composition according to any one of (1) to (3), further containing 50 to 400 ppm of a carboxylic acid (D) having a pKa in the range of 3.5 to 5.5.
However, the content of the carboxylic acid (D) is determined by extracting 10 g of the resin composition with 50 ml of pure water at 95 ° C. for 8 hours, and then measuring the obtained extract by titration.
(5) A molded product containing the resin composition according to any one of (1) to (4).
(6) The molded product according to (5), which is a multi-layer structure including a layer made of the resin composition.
(7) A packaging material having the molded product according to (5) or (6).

The resin composition of the present invention suppresses the generation of kogation even in a repeated melt molding process, and is also excellent in coloring resistance under basic conditions. Moreover, since the resin composition of the present invention is economically provided, it can be applied to various packaging materials.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited thereto. Further, as the illustrated material, one kind may be used alone, or two or more kinds may be used in combination.

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

(In formula (X), Z ¹ and Z ² are independently hydrogen atoms or methyl groups, respectively.)

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 is preferably in the range of 4.0 to 5.5 at 20 ° C. When the pH of the extract is in this range, the pH buffering capacity of the resin composition is enhanced, and the melt moldability and coloring by an acidic substance or a basic substance can be further improved. The pH of the extract can be controlled by changing the type and content of the metal ion (C), the carboxylic acid (D), etc., which will be described later. Hereinafter, each component will be described.

<EVOH (A)>
EVOH (A) is the main component of the resin composition of the present invention. EVOH (A) is a copolymer having an ethylene unit and a vinyl alcohol unit as a main structural unit. EVOH (A) is usually obtained by polymerizing ethylene and vinyl ester and saponifying the obtained 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 monomeric units in EVOH (A)) should be in the range of 15-60 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 may be lowered, and the melt moldability may also be deteriorated. On the contrary, if the ethylene unit content of EVOH (A) exceeds 60 mol%, sufficient gas barrier properties may not be obtained.

The degree of saponification of EVOH (A) (that is, the ratio of the number of vinyl alcohol units to the total number of vinyl alcohol units and vinyl ester units in EVOH (A)) needs to be 85 mol% or more. The lower limit of the saponification degree of EVOH (A) is preferably 95 mol%, more preferably 99 mol%. On the other hand, the upper limit of the saponification degree of EVOH (A) is preferably 100 mol%, more preferably 99.99 mol%. If the saponification degree of EVOH (A) is less than 85 mol%, sufficient gas barrier properties may not be obtained, and thermal stability may be 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 mixed mass ratio is taken as the ethylene unit content. In this case, the difference in ethylene unit content between EVOHs having the farthest ethylene unit content is preferably 30 mol% or less, more preferably 20 mol% or less, still more preferably 15 mol% or less. Similarly, when EVOH (A) is composed of a mixture of two or more types of EVOH having different saponification degrees, the average value calculated from the mixed mass ratio is taken as the saponification degree 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. If a resin composition having a higher level of thermoformability and gas barrier properties is desired, an EVOH having an ethylene unit content of 24 mol% or more and less than 34 mol% and a saponification degree of 99 mol% or more is desired. (A-1) and EVOH (A-2) having an ethylene unit content of 34 mol% or more and less than 50 mol% and a saponification degree of 99 mol% or more are blended in a mass ratio (A-1 / A-). It is preferable to mix 2) so that it becomes 60/40 to 90/10 and use it as EVOH (A). The ethylene unit content and saponification degree of EVOH (A) can be determined by a nuclear magnetic resonance (NMR) method.

The lower limit of the melt flow rate (hereinafter, also simply referred to as "MFR"; temperature 210 ° C., load 2160 g) in accordance with JIS K 7210: 2014 of EVOH (A) is usually 0.1 g / 10 minutes, and the upper limit is usually. 50 g / 10 minutes.

EVOH (A) can contain monomer units other than ethylene units, vinyl alcohol units and vinyl ester units as copolymerization units as long as the object of the present invention is not impaired. Examples of the monomer include α-olefins such as propylene, 1-butene, isobutene, 4-methyl-1-pentene, 1-hexene and 1-octene; itaconic acid, methacrylic acid, acrylic acid and maleic acid. Unsaturated carboxylic acids such as, salts thereof, partial or complete esters thereof, nitriles thereof, amides thereof, anhydrides thereof; vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (β-methoxyethoxy) silane, γ-methacryloxypropyl. Examples thereof include vinylsilane compounds such as trimethoxysilane; unsaturated sulfonic acid or salts thereof; unsaturated thiols; and vinylpyrrolidones. The content of the monomer unit other than the ethylene unit, vinyl alcohol unit and vinyl ester unit in EVOH (A) is usually 5 mol% or less, preferably 2 mol% or less, and more preferably 1 mol% or less.

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

<Compound (B)>
The resin composition of the present invention contains the compound (B) represented by the following formula (X). By containing a predetermined amount of the compound (B) in the resin composition of the present invention, the generation of kogation is suppressed even in the repeated melt molding process. Although the reason for suppressing the generation of kogation is not clear, the compound (B) behaves like a lubricant, and the friction between the resin composition and the surface of the screw or die is reduced during melt molding of the resin composition of the present invention, resulting in a deteriorated resin. It is considered that this is because the adhesion of the resin and the local shear heat generation can be reduced. In addition, the resin composition of the present invention also has improved color resistance under basic conditions. The reason why the coloring resistance is improved is not clear, but it is considered that the adjacent nitrile group in the compound (B) interacts with the base component.

(In formula (X), Z ¹ and Z ² are independently hydrogen atoms or methyl groups, respectively.)

The content of the compound (B) in the resin composition needs to be in the range of 5 to 100 ppm. The lower limit of the content of compound (B) is preferably 10 ppm. On the other hand, the upper limit of the content of the compound (B) is preferably 60 ppm. When the content of the compound (B) is less than 5 ppm, the generation of kogation is not sufficiently suppressed in the repeated melt molding process, and the long-run property becomes insufficient. On the other hand, when the content of the compound (B) exceeds 100 ppm, the coloring resistance under basic conditions becomes insufficient, which may cause a problem. The content of compound (B) in the resin composition can be determined by a nuclear magnetic resonance (NMR) method.

<Metal ion (C)>
The resin composition of the present invention preferably further contains a metal ion (C). By containing the metal ion (C), the resin composition of the present invention has excellent interlayer adhesiveness when formed into a multi-layered molded product. The reason why the metal ion (C) improves the interlayer adhesion is not clear, but when the layer adjacent to EVOH (A) has a molecule having a functional group capable of reacting with the hydroxy group of EVOH (A), it is possible. It is considered that this bond formation reaction is accelerated by the metal ion (C). Further, by controlling the content ratio of the metal ion (C) and the carboxylic acid (D) described 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 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 resin composition is preferably 400 ppm, more preferably 350 ppm. When the content of the metal ion (C) in the resin composition is less than 100 ppm, the interlayer adhesiveness of the obtained multilayer structure may be insufficient. On the other hand, when the content of the metal ion (C) in the resin composition exceeds 400 ppm, the coloring resistance may be insufficient.

Examples of the metal ion (C) include an alkali metal ion, an alkaline earth metal ion, and other transition metal ions, and these may be used alone or in combination of two or more. .. Above all, it is preferable that the metal ion (C) contains an alkali metal ion, and it is more preferable that the metal ion (C) is composed of only an alkali metal ion. Since the metal ion (C) is composed of only alkali metal ions, not only the manufacturing method can be simplified, but also the interlayer adhesiveness of the multilayer structure can be further improved.

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

Examples of alkali metal salts that give alkali metal ions include aliphatic carboxylates of alkali metals such as lithium, sodium, and potassium, aromatic carboxylates, carbonates, hydrochlorides, nitrates, sulfates, phosphates, and metals. Examples include complexes. Of these, sodium acetate, potassium acetate, sodium phosphate, and potassium phosphate are more preferable because they are easily available.

The metal ion (C) may preferably contain an alkaline earth metal ion. When the metal ion (C) contains an alkaline earth metal ion, the thermal deterioration of EVOH (A) when the trim is reused may be suppressed, and the generation of gel and lumps in the molded product may be suppressed.

Examples of the alkaline earth metal ion include berylium, magnesium, calcium, strontium, and barium ions, but magnesium or calcium ions are preferable from the viewpoint of industrial availability.

Examples of alkaline earth metal salts that give alkaline earth metal ions include aliphatic carboxylates, aromatic carboxylates, carbonates, hydrochlorides, nitrates, sulfates, and phosphorus of alkaline earth metals such as magnesium and calcium. Examples thereof include acid salts and metal complexes.

<Carboxylic acid (D)>
The resin composition of the present invention preferably further contains a carboxylic acid (D) having a pKa in the range of 3.5 to 5.5. When the resin composition of the present invention contains the carboxylic acid (D), the melt moldability of the resin composition and the coloring resistance at high temperatures can be further improved. In particular, when the pKa of the carboxylic acid (D) is in the range of 3.5 to 5.5, the pH buffering capacity of the obtained resin composition is enhanced, and the coloring by an acidic substance or a basic substance can be further improved. It may be possible.

The lower limit of the content of the carboxylic acid (D) in the 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 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 temperatures may be insufficient. On the other hand, when the content of the carboxylic acid (D) in the resin composition exceeds 400 ppm, the melt moldability may be insufficient or the odor may become a problem. The content of the carboxylic acid (D) is determined by extracting 10 g of the resin composition with 50 ml of pure water at 95 ° C. for 8 hours, and then measuring the obtained extract by titration. Here, as the content of the carboxylic acid (D) in the resin composition, the carboxylic acid present as a salt in the extract is not taken into consideration.

Examples of the carboxylic acid (D) include monovalent carboxylic acid and polyvalent carboxylic acid, and these may be used alone or in combination of two or more. When the resin composition contains both a monovalent carboxylic acid and a polyvalent carboxylic acid as the carboxylic acid (D), the melt moldability and the coloring resistance at high temperatures may be significantly improved. Further, the polyvalent carboxylic acid may have three or more carboxyl groups. In this case, the coloring resistance of the resin composition of the present invention may be improved more effectively.

The monovalent carboxylic acid is a compound having one carboxyl group in the molecule. The monovalent carboxylic acid having a pKa in the range of 3.5 to 5.5 is not particularly limited, and is, for example, formic acid (pKa = 3.77), acetic acid (pKa = 4.76), and propionic acid (pKa = 4). .85), butylic acid (pKa = 4.82), caproic acid (pKa = 4.88), caproic acid (pKa = 4.90), lactic acid (pKa = 3.86), acrylic acid (pKa = 4.25). ), Methoxylic acid (pKa = 4.65), benzoic acid (pKa = 4.20), 2-naphthoic acid (pKa = 4.17) and the like. These carboxylic acids may further have substituents such as hydroxyl groups, amino groups and halogen atoms as long as pKa is in the range of 3.5 to 5.5. Among these, acetic acid is preferable because it is highly safe and easy to handle.

A polyvalent carboxylic acid is a compound having two or more carboxyl groups in the molecule. In this case, the pKa of at least one carboxyl group may be in the range of 3.5 to 5.5, for example, oxalic acid (pKa ₂ = 4.27), succinic acid (pKa ₁ = 4.20), fumal. 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), 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), tartrate acid (pKa ₂ = 4.40), glutamic acid (pKa ₂ = 4.07), aspartic acid (pKa = 3.90), etc. Can be mentioned.

<Other ingredients>
The resin composition of the present invention may contain other components as long as the effects of the present invention are not impaired. Other components include, for example, phosphoric acid compounds, boron compounds, thermoplastic resins other than EVOH (A), cross-linking agents, desiccants, antioxidants, antioxidants, oxygen absorbers, plasticizers, lubricants, heat stabilizers. (Melting stabilizers), processing aids, surfactants, deodorants, antistatic agents, UV absorbers, antifogging agents, flame retardants, pigments, dyes, fillers, fillers, reinforcing agents for various fibers, etc. Be done.

<Phosphoric acid compound>
When a phosphoric acid compound is contained, the lower limit of the content thereof in the resin composition is preferably 1 ppm, more preferably 10 ppm in terms of phosphoric acid root. 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 phosphoric acid root. By containing the phosphoric acid compound in this range, the thermal stability of the resin composition can be improved. In particular, it may be possible to suppress the generation and coloring of gel-like lumps during melt molding for a long period of time.

As the phosphoric acid compound, for example, various acids such as phosphoric acid and phosphoric acid and salts thereof can be used. The phosphate may be any of a first phosphate, a second phosphate, and a third phosphate. The cation species of the phosphate is not particularly limited, but it is preferable that the cation species is an alkali metal or an alkaline earth metal. Among them, as the phosphoric acid compound, sodium dihydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate, and dipotassium hydrogen phosphate are preferable.

<Boron compound>
When a boron compound is contained, the lower limit of the content thereof in the resin composition is preferably 5 ppm, more preferably 10 ppm in terms of elemental boron. On the other hand, the upper limit of the content in the resin composition is preferably 1000 ppm, more preferably 500 ppm in terms of elemental boron. By containing the boron compound in this range, the thermal stability of the resin composition during melt molding may be improved and the generation of gel-like lumps may be suppressed. In addition, the mechanical properties of the obtained molded product may be improved. It is speculated that these effects are due to the occurrence of chelate interactions between EVOH (A) and the boron compound.

Examples of the boron compound include boric acid, borate ester, borate, and boron hydride. Specifically, examples of boric acid include orthoboric acid (H ₃ BO ₃ ), metaboric acid, and tetraboric acid, and examples of boric acid esters include, for example, trimethyl borate and triethyl borate, boric acid. Examples of the salt include the alkali metal salt of boric acid, an alkaline earth metal salt, boric acid and the like. Of these, orthoboric acid is preferable.

Examples of the thermoplastic resin other than EVOH (A) include various polyolefins (polyethylene, polypropylene, poly1-butene, poly4-methyl-1-pentene, ethylene-propylene copolymer, ethylene and α-with 4 or more carbon atoms. A copolymer with an olefin, a copolymer of a polyolefin and maleic anhydride, an ethylene-vinyl ester copolymer, an ethylene-acrylic acid ester copolymer, or a modification obtained by graft-modifying these with an unsaturated carboxylic acid or a derivative thereof. Polyethylene, etc.), various polyamides (nylon 6, nylon 6.6, nylon 6/66 copolymer, nylon 11, nylon 12, polymethoxylylen adipamide, etc.), various polyesters (polyethylene terephthalate, polybutylene terephthalate, polyethylene na) Phthalates, etc.), polyvinyl chloride, polyvinylidene chloride, polystyrene, polyacrylonitrile, polyurethane, polycarbonate, polyacetal, polyacrylate, modified polyvinyl alcohol resin, and the like. The content of the thermoplastic resin in the resin composition is usually less than 30% by mass, preferably less than 20% by mass, and more preferably less than 10% by mass.

<Manufacturing method of resin composition>
The method for producing the resin composition of the present invention is a method in which the compound (B) can be uniformly mixed in EVOH (A), and the finally obtained resin composition contains 5 to 100 ppm of the compound (B). If so, it is not particularly limited. Preferred production methods include a copolymerization step (I) in which ethylene and vinyl ester are copolymerized to obtain an ethylene-vinyl ester copolymer, and a saponification step (I) in which the ethylene-vinyl ester copolymer is saponified to obtain EVOH (A). Includes step (II), granulation step (III) to obtain water-containing pellets of EVOH (A) by granulation operation, and drying step (IV) to dry the water-containing pellets to obtain a resin composition containing EVOH (A). After the copolymerization step (I), a method including a mixing step of mixing an ethylene-vinyl ester copolymer or an EVOH (A) with a compound (B) can be mentioned. In this case, the content of the compound (B) in the finally obtained resin composition can be easily controlled by adjusting the amount of the compound (B) added in the mixing step. Further, a washing operation for removing the compound (B) may be performed if necessary. The content of the compound (B) can be adjusted by a washing operation by adjusting the paste concentration and temperature at the time of precipitating the EVOH (A) paste in the granulation step (III), the composition and temperature of the coagulation bath, and thereafter. This can be done by appropriately adjusting the type, temperature, soaking time and number of times of the solution in which the water-containing pellet of EVOH (A) is immersed in the step. Further, the compound (B) is contained in the resin composition by adding a poor solvent little by little to a solution obtained by dissolving the dried resin composition in a good solvent, precipitating and precipitating the resin composition, and recovering the resin composition. Reducing the amount to a required amount is also effective as a method for adjusting the content of the compound (B).

As a mixing step of adding the compound (B) to the EVOH (A) after the copolymerization step (I), for example, a method of adding the compound (B) during or after the saponification reaction, and precipitating the paste of the EVOH (A). A method of impregnating the strands precipitated in the step of impregnating the compound (B), a method of impregnating the precipitated strands with the compound (B) after cutting the strands, and a compound (a compound) obtained by redissolving a dried EVOH (A) chip. A method of adding B), a method of melt-kneading a blend of two components of EVOH (A) and compound (B), and a powder of compound (B) in a melt of EVOH (A) from the middle of an extruder. A method of feeding as a solution or a dispersion and melt-kneading, compound (B) is mixed with a part of EVOH (A) at a high concentration to prepare a granulated master batch, and the master batch and EVOH (A) are combined. Examples thereof include a method of dry-blending and then melt-kneading.

Among these, from the viewpoint that a trace amount of the compound (B) can be uniformly dispersed in the EVOH (A), as a mixing step of adding the compound (B) to the EVOH (A), the compound (B) is added after the saponification reaction. The method of adding to EVOH (A) is preferable. Specifically, compound (B) is added to a solution obtained by dissolving EVOH (A) obtained in the saponification step in a good solvent such as a water / methanol mixed solvent, and the mixed solution is put into a poor solvent from a nozzle or the like. A resin composition in which the compound (B) is uniformly mixed with EVOH (A) by cutting the extruded and precipitated strands to obtain hydrous pellets, washing the pellets as necessary, and then drying the pellets. Pellets can be obtained.

As a method for incorporating each component other than the compound (B) into the resin composition of the present invention, for example, pellets of the above resin composition in which the compound (B) is mixed with EVOH (A) are mixed together with each component. A method of melt-kneading, a method of mixing each component at the same time as EVOH (A) and compound (B) when preparing pellets of the above resin composition, and a method of immersing the pellet of the above resin composition in a solution containing each component. There is a method of making it. At this time, both the hydrous pellet and the dry pellet can be used as the pellet of the resin composition.

<Copolymerization step (I)>
In the copolymerization step, in addition to the step of copolymerizing ethylene and vinyl ester, a polymerization inhibitor is added as necessary, and then unreacted ethylene and unreacted vinyl ester are removed to remove ethylene-vinyl ester copolymer weight. Includes the step of obtaining a coalesced solution. Examples of the copolymerization method of ethylene and vinyl ester include known methods such as solution polymerization, suspension polymerization, emulsion polymerization and bulk polymerization. Vinyl acetate is mentioned as a typical vinyl ester used for polymerization, but other aliphatic vinyl esters such as vinyl propionate and vinyl pivalate can also be used. In addition, a small amount of copolymerizable monomers can be copolymerized. The polymerization temperature is preferably 20 to 90 ° C, more preferably 40 to 70 ° C. The polymerization time is preferably 2 to 15 hours, more preferably 3 to 11 hours. The polymerization rate is preferably 10 to 90%, more preferably 30 to 80% with respect to the charged vinyl ester. The resin content in the solution after the polymerization is preferably 5 to 85% by mass, more preferably 20 to 70% by mass.

The initiator used in the copolymerization step (I) is not particularly limited, but it is preferable to use an azonitrile-based polymerization initiator. The radical generation rate and solubility in a solvent can be controlled by the molecular skeleton of the azonitrile-based polymerization initiator. In addition, the azonitrile-based polymerization initiator is less likely to cause decomposition induced by metal contact or the like, and is less susceptible to the influence of the solvent during decomposition. Therefore, by using the azonitrile-based polymerization initiator, the polymerization step can be carried out safely and stably. Examples of the azonitrile-based polymerization initiator include 4,4'-azobis (4-cyanovaleric acid), 1,1'-azobis (cyclohexane-1-carbonitrile), and 2,2'-azobis (2-methylbuty). Lonitrile), 2,2'-azobis (isobutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (4-methoxy-2,4-dimethylvalero) Nitrile) can be mentioned. Among these, 2,2'-azobis (2,4-dimethylvaleronitrile) and 2,2'-azobis (4-methoxy-2) can be rapidly promoted at a relatively low temperature. , 4-Dimethylvaleronitrile) can be preferably used.

<Saponification process (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, either a continuous method or a batch method can be adopted. Examples of the alkali catalyst include sodium hydroxide, potassium hydroxide, and alkali metal alcoholate. Further, after the saponification step, an acid such as acetic acid is generally added to neutralize the remaining alkaline catalyst.

<Granulation process (III)>
Examples of the granulation operation include (1) a method of extruding a solution of EVOH (A) into a low-temperature poor solvent to precipitate or solidify it, and immediately after that, or after further cooling and solidifying it, and (2) cutting EVOH (A). ) Is brought into contact with water vapor to obtain a water-containing resin composition of EVOH (A) in advance, and then the water-containing resin composition is cut. The water content in the water-containing pellets of EVOH (A) obtained by these methods is preferably 50 to 200 parts by mass, preferably 70 to 150 parts by mass with respect to 100 parts by mass of EVOH (A). Is more preferable.

<Drying process (IV)>
It is preferable to dry the water-containing pellets of EVOH (A) obtained in the granulation step to obtain dried pellets of EVOH (A). The amount of water in the dried pellets is preferably 1.0 part by mass or less, preferably 0.5 part by mass or less, with respect to 100 parts by mass of EVOH (A), for the purpose of preventing troubles during molding such as generation of voids. It is more preferably 0.3 parts by mass or less, and further preferably 0.3 parts by mass or less. Examples of the method for drying the water-containing pellets include static drying and fluid drying. These drying methods may be used alone or in combination of two or more. The drying treatment may be performed by either a continuous method or a batch method. When a plurality of drying methods are combined, a continuous method or a batch method can be freely selected for each drying method. It is also preferable to perform drying in a low oxygen concentration or anoxic state in that deterioration of the resin composition due to oxygen during drying can be reduced.

<Molded body>
A molded product containing the resin composition of the present invention is a preferred embodiment of the present invention. The resin composition of the present invention may be a molded body having a single-layer structure, or may be a molded body having a multi-layer structure having a layer made of the resin composition and another layer, that is, a multi-layer structure. can. Examples of the molding method include extrusion molding, thermoforming, malformed molding, hollow molding, rotary molding, and injection molding. The molded product of the present invention has a wide range of uses, and films, sheets, containers, bottles, tanks, pipes, hoses and the like are exemplified as suitable ones.

The following methods are exemplified as specific molding methods. Films, sheets, pipes, hoses, etc. can be obtained by extrusion molding. 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 tank, it can be obtained by hollow molding or rotary molding. Examples of the hollow molding include extrusion hollow molding in which a parison is obtained by extrusion molding and then blown to form the preform, and injection hollow molding in which a preform is formed by injection molding and then blown to form the preform. .. As a method for molding a flexible packaging material or a container, a method for obtaining a packaging material such as a multilayer film by extrusion molding and a method for thermoforming a multilayer sheet obtained by extrusion molding into a container-shaped packaging material are preferably used. ..

<Multi-layer structure>
A multilayer structure including a layer made of the resin composition of the present invention is a more preferred embodiment of the present invention. The multilayer structure is formed by laminating a layer made of the resin composition of the present invention and another layer. As the layer other than the resin composition layer, a layer made of a resin other than EVOH (A) is preferable. Further, the multilayer structure may further have a layer made of an adhesive resin. As the layer structure of the multilayer structure, when a layer made of a resin other than EVOH (A) is an x layer, the resin composition layer of the present invention is a y layer, and the adhesive resin layer is a z layer, 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. Can be mentioned. When a plurality of x-layers, y-layers, and z-layers are provided, the types may be the same or different. Further, a layer using a recovery resin made of scrap such as trim generated during molding may be separately provided, or the recovery resin may be blended with a layer made of a resin other than EVOH (A). The thickness and composition of each layer of the multilayer structure are not particularly limited, but the thickness ratio of the y layer to the total layer thickness is usually 2 to 20% from the viewpoint of moldability and cost.

As the resin used for the x layer, a thermoplastic resin is preferable from the viewpoint of processability and the like. Examples of the thermoplastic resin include various polyolefins (polyethylene, polypropylene, poly1-butene, poly4-methyl-1-pentene, ethylene-propylene copolymer, and a copolymer of ethylene and α-olefin having 4 or more carbon atoms. , Polypolymer of polyolefin and maleic anhydride, ethylene-vinyl ester copolymer, ethylene-acrylic acid ester copolymer, or modified polyolefin obtained by graft-modifying these with unsaturated carboxylic acid or a derivative thereof), various polyamides (Nylon 6, Nylon 6.6, Nylon 6/66 copolymer, Nylon 11, Nylon 12, Polymethoxylylen adipamide, etc.), Various polyesters (Polyethylene terephthalate, Polybutylene terephthalate, Polyethylene naphthalate, etc.), Polychloride Examples thereof include vinyl, polyvinylidene chloride, polystyrene, polyacrylonitrile, polyurethane, polycarbonate, polyacetal, polyacrylate and modified polyvinyl alcohol resin. The thermoplastic resin layer may be unstretched, or may be uniaxially or biaxially stretched or rolled. Among these thermoplastic resins, polyolefin is preferable in terms of moisture resistance, mechanical properties, economy, heat sealability and the like, and polyamide and polyester are preferable in terms of mechanical properties, heat resistance and the like.

The adhesive resin used for the z-layer is not particularly limited as long as it can adhere each layer, and polyurethane-based or polyester-based one-component or two-component curable adhesives, carboxylic acid-modified polyolefins, and the like are used. It is preferably used. The carboxylic acid-modified polyolefin is a polyolefin-based copolymer containing an unsaturated carboxylic acid or an anhydride thereof (maleic anhydride, etc.) as a copolymerization component; or a graft obtained by grafting an unsaturated carboxylic acid or an anhydride thereof onto a polyolefin. It is a copolymer.

Examples of the method for obtaining the multilayer structure of the present invention include co-extrusion molding, co-extrusion hollow molding, co-injection molding, extrusion laminating, co-extrusion laminating, dry laminating, solution coating and the like. The multilayer structure obtained by such a method is secondarily heated after being reheated in a range below the melting point of EVOH (A) by a method such as vacuum or pressure-pneumatic deep drawing, blow molding, or press molding. It may be processed and molded to obtain a desired molded body. Further, the multilayer structure is stretched by uniaxial or biaxial stretching after reheating within the range below the melting point of EVOH (A) by a roll stretching method, a pantograph stretching method, an inflation stretching method, or the like. You can also get a structure.

The resin composition of the present invention suppresses the generation of kogation even in a repeated melt molding process, and is also excellent in coloring resistance under basic conditions. Moreover, the resin composition of the present invention can be economically provided. Therefore, the resin composition of the present invention is molded into a film, a sheet, a container, or the like, and is suitably used as various packaging materials. A packaging material having a molded product containing the resin composition of the present invention is a preferred embodiment of the present invention.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. 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) to tetramethylsilane (TMS) as an internal standard and heavy dimethyl sulfoxide (DMSO-d ₆ ) containing trifluoroacetic acid (TFA) as an additive. Dissolve and measure at 80 ° C. using ¹ H-NMR (manufactured by Nippon Denshi Co., Ltd .: "GX-500") at 500 MHz, and the ethylene unit content is based on the peak intensity ratio of ethylene unit, vinyl alcohol unit, and vinyl ester unit. And the degree of saponification was calculated.

(2) Content of compound (B) The dried pellet was dissolved in DMSO-d ₆ containing TMS as an internal standard substance, and ¹ H-NMR at 500 MHz (manufactured by Nippon Denshi Co., Ltd .: “GX-500”) was used. The content of compound (B) is measured at 45 ° C. based on the ratio of the peak intensity of ethylene unit, vinyl alcohol unit and vinyl ester unit to the peak intensity of methyl hydrogen of methoxy group or methylene hydrogen of ethoxy group of compound (B). Asked for the amount. The peak of methyl hydrogen of the methoxy group or methylene hydrogen of the ethoxy group of the compound (B) was detected at around 3.13 ppm.

(3) Content of metal ion (C) 0.5 g of dried pellets was 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 the decomposition, the container was covered, and then further decomposed by heating at 150 ° C. for 10 minutes and then at 180 ° C. for 5 minutes by a wet decomposition apparatus, and then cooled to room temperature. This treatment liquid was transferred to a 50 mL volumetric flask and measured with pure water. The content of each metal ion in the dried pellet was quantified by measuring this solution with an ICP emission spectrophotometer. The contents of the phosphoric acid compound and the boron compound can also be quantified by the same method.

(4) Content of carboxylic acid (D) 10 g of dried pellets and 50 mL of pure water were put into a 100 mL Erlenmeyer flask with a stopper, a cooling condenser was attached, and the mixture was stirred 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 a 0.02 mol / L sodium hydroxide aqueous solution using phenolphthalein as an indicator.

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

(6) Evaluation of koge Using 2 kg of dried pellets, pelletizing was performed with a single-screw extruder (Toyo Seiki Co., Ltd. D2020, diameter 20 mmφ, L / D20, full flight screw) to obtain pellets melt-molded once. .. The temperature conditions were supply unit / compression unit / measurement unit / die = 175/215/225/220 ° C., and the screw rotation speed was 50 rpm. The obtained melt-molded pellets were pelletized again under the same conditions to obtain pellets melt-molded twice. In the same manner, pelletizing was repeated 5 times in total, and then purged (washed) with 500 g of high-density polyethylene in a single-screw extruder. Next, the screw was pulled out, the state of adhesion of kogation on the screw was visually confirmed, and then the sample was collected and weighed, and evaluated according to the following criteria A to D, which was used as an index for evaluation of kogation.
A: The color of the koge was pale yellow and the amount was less than 0.1 g. B: The color of the koge was yellow or brown and the amount was less than 0.1 g. C: The color of the koge was yellow or brown. The amount was 0.1 g or more and less than 0.3 g. D: The color of the koge was yellow or brown, and the amount was 0.3 g or more.

(7) Coloring resistance 100 g of dried pellets was immersed in 1000 g of a 0.1 mol / L sodium hydroxide aqueous solution, the container containing the pellets was covered, and the mixture was allowed to stand at 80 ° C. for 1 week. The YI (yellow index) value of the pellets before and after immersion was measured using "LabScan XE Sensor" manufactured by HunterLab, and the amount of increase in YI due to immersion was determined and evaluated according to the following criteria A to D. This evaluation result was used as an index of the coloring resistance of the resin composition under basic conditions. The YI value is an index showing the yellowness (yellowness) of the object, and the higher the YI value, the stronger the yellowness, while the lower the YI value, the weaker the yellowness and less coloring. ..
A: YI increase is less than 2 B: YI increase is 2 or more and less than 4 C: YI increase is 4 or more and less than 6 D: YI increase is 6 or more

(8) Appearance characteristics after melt molding Using 10 g of dried pellets, they were heated and melted at 220 ° C. for 6 minutes at 220 ° C. to prepare a disk-shaped sample having 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 according to the following criteria A to D. This evaluation result was used as an index of the appearance characteristics after melt molding.
A: YI is less than 8 B: YI is 8 or more and less than 13 C: YI is 13 or more and less than 20 D: YI is 20 or more

(9) Interlayer adhesiveness Dry pellets, linear low-density polyethylene (Novatec LL-UF943 manufactured by Nippon Polyethylene, hereinafter abbreviated as LLDPE) and adhesive resin (Vinel CXA417E10 manufactured by DuPont) were diluted to 7% with the above LLDPE. , Hereinafter abbreviated as Ad), a three-kind, five-layer multilayer film (LLDPE / Ad / EVOH / Ad / LLDPE = 50 μm / 10 μm / 10 μm / 10 μm / 50 μm) was formed. The extruder, extrusion conditions, and die used were as follows.
Extruder:
EVOH: Single-screw extruder (Toyo Seiki Co., Ltd. Lab machine ME type CO-EXT)
Diameter 20 mmφ, L / D20, full flight screw supply part / compression part / measuring part / die = 175/210/220/220 ° C.
LLDPE: Single-screw extruder (Plastic Engineering Laboratory Co., Ltd. GT-32-A)
Diameter 32 mmφ, L / D28, full flight screw supply part / compression part / measuring part / die = 150/200/210/220 ° C.
Ad: Single-screw extruder (Technobel Co., Ltd. SZW20GT-20MG-STD)
Diameter 20 mmφ, L / D20, full flight screw supply part / compression part / measuring part / die = 150/200/220/220 ° C.
Die: Coat hanger die for 3 types and 5 layers with a width of 300 mm (manufactured by Plastic Engineering Research Institute)

The multilayer film obtained 15 minutes after the start of the film formation was adjusted to a humidity of 23 ° C. and a relative humidity of 50% RH, and then had a length of 150 mm and a width of 15 mm along the extrusion direction. The sample was cut out. The peel strength of the sample was measured using an Autograph DCS-50M type tensile tester manufactured by Shimadzu Corporation (atmosphere of 23 ° C, 50% RH, tensile speed 250 mm / min, T-type peeling mode), and the following. It was evaluated according to the criteria of A to C. This evaluation result was used as an index of interlayer adhesive strength.
A: 500 g / 15 mm or more B: 300 g / 15 mm or more and less than 500 g / 15 mm C: 300 g / less than 15 mm

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

When the polymerization rate of vinyl acetate reached about 40%, sorbic acid was added and cooled to terminate the polymerization. Next, the reaction tank was opened to deethylene, and then supplied to the expulsion column. Unreacted vinyl acetate was removed from the top of the column by introducing methanol vapor from the lower part of the column, and a methanol solution of ethylene-vinyl acetate copolymer was used. Got This solution was charged into a saponification reactor, and a sodium hydroxide / methanol solution (80 g / L) was added so that the molar ratio of sodium hydroxide to the vinyl ester unit in the copolymer was 0.7, and methanol was added. Was added to adjust the copolymer concentration to 15%. The temperature of this solution was raised to 60 ° C., and the saponification reaction was carried out for about 4 hours while blowing nitrogen gas into the reactor. Then, acetic acid and water were added to the reaction solution to stop the saponification reaction, an EVOH suspension was obtained, and then the solution was drained by a centrifugal drainer. The operation of adding acetonitrile to the obtained EVOH so that the molar ratio of acetonitrile to all the monomer units in EVOH was 2, and then removing the liquid was repeated twice. Further, the operation of adding a large amount of water to the EVOH and removing the liquid was repeated. Then, it was dried at 60 ° C. for 24 hours to obtain a crudely dried EVOH having an ethylene unit content of 32 mol% and a saponification degree of 99.9 mol%.

[Synthesis Example 2]
A crude dried product of EVOH having an ethylene unit content of 32 mol% and a saponification degree of 99.9 mol% by the same operation as in Synthesis Example 1 except that the conditions at the time of polymerization of the ethylene-vinyl acetate copolymer were changed to the following. Got
・ Vinyl acetate: 83.0 kg
-Methanol: 26.6 kg
-Initiator: 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile) (2.5 g / L methanol solution), initial supply amount: 362 mL, continuous supply amount: 1120 mL / hr
-Polymerization temperature: 60 ° C
-Polymerization tank ethylene pressure: 3.6 MPa

[Synthesis Example 3]
A crude dried product of EVOH having an ethylene unit content of 44 mol% and a saponification degree of 99.9 mol% by the same operation as in Synthesis Example 1 except that the conditions at the time of polymerization of the ethylene-vinyl acetate copolymer were changed to the following. Got
-Vinyl acetate: 76.7 kg
-Methanol: 11.0 kg
-Initiator: 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile) (2.5 g / L methanol solution), initial supply amount: 510 mL, continuous supply amount: 1570 mL / hr
-Polymerization temperature: 60 ° C
-Polymerization tank ethylene pressure: 5.5 MPa

[Examples 1 to 9 and Comparative Examples 1 to 5]
The crude EVOH obtained in Synthesis Example 1 was placed in a mixed solvent of water / methanol = 40/60 (mass ratio) so as to have a solid content of 40%, and dissolved by stirring at 60 ° C. for 6 hours. rice field. The compound (B) in which Z ¹ and Z ² in the above formula (X) are hydrogen atoms was added to the obtained solution, and the mixture was further stirred for 1 hour, and then water / methanol adjusted to 0 ° C. from a nozzle having a diameter of 4 mm. = 90/10 (mass ratio) was continuously extruded into a precipitation bath to precipitate in the form of strands. This strand was introduced into a pelletizer to obtain porous hydrous pellets. The water-containing pellets were washed with an aqueous acetic acid solution and ion-exchanged water, and then immersed in an aqueous solution containing sodium acetate and acetic acid. The aqueous solution and the hydrous pellet were separated and drained, and then placed in a hot air dryer and dried at 80 ° C. for 3 hours and then at 110 ° C. for 35 hours to obtain dried pellets. The dry pellets were used for the analysis and evaluation described above. The resin composition having the composition shown in Table 1 was produced by adjusting the addition amount of the compound (B) and the concentration of each component of the aqueous solution for immersion treatment.

[Example 10]
Dry pellets were produced, analyzed and evaluated by the same operation as in Example 1 except that potassium acetate was used instead of sodium acetate.

[Example 11]
Dry pellets were produced and analyzed and evaluated by the same operation as in Example 1 except that sodium lactate was used instead of sodium acetate and lactic acid was used instead of acetic acid.

[Example 12]
Dry pellets were produced and analyzed and evaluated by the same operation as in Example 1 except that sodium trifluoroacetate was used instead of sodium acetate and trifluoroacetic acid was used instead of acetic acid.

[Example 13]
Dry pellets were produced, analyzed and evaluated by the same operation as in Example 1 except that the crude EVOH obtained in Synthesis Example 2 was used.

[Example 14]
Using the crude EVOH obtained in Synthesis Example 3 above, dry pellets were prepared by the same operation as in Example 1 except that a mixed solvent of water / methanol = 25/75 (mass ratio) was used for dissolution. It was manufactured, analyzed and evaluated.

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

Claims (7)

A method for producing a resin composition containing an ethylene-vinyl alcohol copolymer (A) and a compound (B) represented by the following formula (X).
An ethylene-vinyl alcohol copolymer (II) is obtained by saponifying an ethylene-vinyl ester copolymer to obtain an ethylene-vinyl alcohol copolymer (A), and a compound (B) is added to the ethylene-vinyl alcohol copolymer (B) after the saponification step (II). Including the mixing step added to A)
The ethylene unit content of the ethylene-vinyl alcohol copolymer (A) is 15 to 60 mol%, the saponification degree is 85 mol% or more, and the content of the compound (B) in the resin composition is 5 to 100 ppm. A method for producing a resin composition.

(In formula (X), Z ¹ and Z ² are independently hydrogen atoms or methyl groups, respectively.) A copolymerization step (I) of copolymerizing ethylene and a vinyl ester to obtain an ethylene-vinyl ester copolymer, and saponifying the ethylene-vinyl ester copolymer to obtain an ethylene-vinyl alcohol copolymer (A). A saponification step (II), a granulation step (III) for obtaining a hydrous pellet of the ethylene-vinyl alcohol copolymer (A) by a granulation operation, and a drying of the hydrous pellet to obtain an ethylene-vinyl alcohol copolymer (A). Including the drying step (IV) to obtain pellets of the containing resin composition,
The method for producing a resin composition according to claim 1, which comprises a mixing step of adding the compound (B) to the ethylene-vinyl alcohol copolymer (A) after the saponification step (II) . In the mixing step, compound (B) is added to a solution obtained by dissolving the ethylene-vinyl alcohol copolymer (A) obtained in the saponification step (II) in a water / methanol mixed solvent, and the mixed solution is dispensed from a nozzle. In the granulation step (III) in which the strands extruded into a poor solvent and precipitated are cut to obtain hydrous pellets, the hydrous pellets are dried, and the compound (B) is mixed with the ethylene-vinyl alcohol copolymer (A). The method for producing a resin composition according to claim 1 or 2, which comprises a drying step (IV) for obtaining pellets of the obtained resin composition . The invention according to any one of claims 1 to 3 , wherein the pH of the extract obtained by extracting 10 g of the resin composition with 50 ml of pure water at 95 ° C. for 8 hours is in the range of 4.0 to 5.5 at 20 ° C. Method for producing the resin composition of. The method for producing a resin composition according to any one of claims 1 to 4, wherein the resin composition further contains 100 to 400 ppm of a metal ion (C). The method for producing a resin composition according to any one of claims 1 to 5 , wherein the resin composition further contains 50 to 400 ppm of a carboxylic acid (D) having a pKa in the range of 3.5 to 5.5. .. A method for producing a molded product containing the resin composition, wherein the resin composition is obtained by the production method according to any one of claims 1 to 6 , and then the resin composition is molded.