JP5787740B2 - Resin composition and multilayer structure and molded article using the same - Google Patents

Description

  The present invention relates to a resin composition containing a saponified ethylene-vinyl ester copolymer as a main component, and more particularly to a resin composition excellent in flexibility and blocking resistance.

  The saponified ethylene-vinyl acetate copolymer (hereinafter sometimes referred to as “EVOH resin”) has a very strong intermolecular force due to hydrogen bonding between hydroxyl groups present in the polymer side chain. Therefore, since the crystallinity is high and the intermolecular force is high even in the amorphous part, gas molecules and the like cannot pass through the EVOH resin film. For these reasons, films using EVOH resin exhibit excellent gas barrier properties and are used as packaging films for water and food / beverage products, and packaging container materials. On the other hand, EVOH resin molded products have the disadvantage that they lack flexibility due to their high crystallinity.

In recent years, when used as a film container filled with liquid, such as a bag for a bag-in-box, the film can accommodate movement that folds the container or bends irregularly according to deformation or weight loss of the liquid inside. Flexibility is required. In environments where liquids that are irregularly shaped are filled for a long time and transported for a long time, the film container will be fatigued by repeated bending of the film due to deformation of the liquid for a long time. There may be pinholes.
Therefore, the film container having such specifications requires flexibility from the viewpoint of durability. The flexibility required in these cases is a characteristic different from hardness, impact resistance, and tensile strength.

  Conventionally, a styrene-based thermoplastic elastomer (B) containing an EVOH resin (A) having an ethylene content of 20 to 60 mol% as a matrix and not containing a polar group as a flexible component, and a styrene-based thermoplastic elastomer containing a polar group as a dispersant (C) An EVOH resin composition containing a hydrocarbon resin (D) having a number average molecular weight of 100 to 3000 and a softening point of 60 ° C. or higher and lower than 170 ° C. as a dispersion aid has been proposed. . (For example, patent document 1).

On the other hand, EVOH resin is excellent in transparency, gas barrier properties, fragrance retention, solvent resistance, oil resistance, etc., and taking advantage of these properties, food packaging materials, pharmaceutical packaging materials, industrial chemical packaging materials, agricultural chemical packaging It is used by being formed into a film or sheet of material or a container such as a bottle. In such molding, the film is usually formed into a film or sheet by melt molding. At this time, the EVOH resin is required to have slipperiness.
That is, the slipperiness between the apparatus wall surface in the molding machine (melting extruder) and the molten EVOH resin, the slipperiness between the apparatus such as a roll and a guide plate during the molding and the EVOH resin molding, Even when the obtained molded product such as a film or sheet is rolled and stored, the slipperiness (blocking resistance) between the molded products is required.

Conventionally, an EVOH resin composition containing an EVOH resin (A), inorganic fine particles (B) and a boron compound (C) has been proposed for the purpose of improving such blocking properties. (For example, patent document 2).
Here, the inclusion of inorganic fine particles in the resin reduces the contact area between devices such as rolls and guide plates at the time of molding and resin molded products and between molded products, so that blocking resistance is improved. It is possible.

JP 2011-6673 A JP 2000-265024 A

However, the EVOH resin composition as proposed in Patent Document 1 is insufficient in blocking resistance. Further, the EVOH resin composition as proposed in Patent Document 2 is insufficient in flexibility. Accordingly, an object of the present invention is to solve the problems of blocking resistance and flexibility, and to provide a resin composition having blocking resistance without impairing flexibility.

In general, when bending is applied to a molded product obtained from a resin composition in which inorganic fine particles are blended in a resin, there is a concern about the occurrence of cracks due to the stress due to the bending concentrated on the interface between the inorganic fine particles and the resin. For this reason, it has been considered undesirable to add inorganic fine particles to a resin composition that requires flexibility.
In the present invention, as a result of intensive studies in view of the above circumstances, an EVOH resin (A) having an ethylene content of 20 to 60 mol%, a styrenic thermoplastic elastomer (B) containing no polar group, and a styrenic thermoplastic containing a polar group. By adding inorganic fine particles (E) to the hydrocarbon resin (D) having an elastomer (C) having a number average molecular weight of 100 to 3000 and a softening point of 60 ° C. or higher and lower than 170 ° C. The present inventors completed the present invention by discovering that the inorganic fine particles were uniformly dispersed without unexpectedly impairing flexibility and having blocking resistance.

The resin composition of the present invention comprises an ethylene-vinyl ester copolymer saponified product (A) having an ethylene content of 20 to 60 mol% as a matrix, and a styrenic thermoplastic elastomer containing no polar group as a soft component ( B) is dispersed. Then, in dispersing the component (B), a styrenic thermoplastic elastomer (C) containing a polar group having affinity for both the component (A) and the component (B) is used as a dispersant. By using a hydrocarbon resin (D) having a number average molecular weight of 100 to 3000 and a softening point of 60 ° C. or higher and lower than 170 ° C. as a dispersion aid, the component (B) is refined and dispersed. Very good. Further, the inorganic fine particles (E) are uniformly dispersed in the resin composition.
As a result, a molded article using the resin composition of the present invention and a multilayer structure including at least one layer made of the resin composition of the present invention are flexible while maintaining the gas barrier property that is characteristic of the EVOH resin. It is possible to obtain a film having excellent blocking resistance.

In the present invention, one of the features is the use of inorganic fine particles (E), and this provides an unexpected effect that the resin composition does not impair the flexibility and has blocking resistance. It is what was done.

  Hereinafter, although it demonstrates in detail about the structure of this invention, these show an example of a desirable embodiment and are not specified by these content.

<Resin composition>
The resin composition of the present invention comprises a saponified ethylene-vinyl ester copolymer saponified product (A) having an ethylene content of 20 to 60 mol% as a main component and does not contain a polar group which is a flexible component as a subsidiary component. A thermoplastic elastomer (B) is dispersed. In dispersing the component (B), a styrenic thermoplastic elastomer (C) containing a polar group and having affinity for both the component (A) and the component (B) is added as a dispersant. By adding a hydrocarbon resin (D) having a number average molecular weight of 100 to 3000 and a softening point of 60 ° C. or higher and lower than 170 ° C. as a dispersion aid, the component (B) is refined and dispersed. Will be very good. Furthermore, the inorganic fine particles (E) are uniformly dispersed in the resin composition as an additive.
Hereinafter, each component will be described in order.

[EVOH resin (A)]
The EVOH resin (A) as the main component of the composition is a water-insoluble resin, and is a known resin obtained by saponifying a copolymer of ethylene and a vinyl ester monomer. Such vinyl ester monomers are typically vinyl acetate. The ethylene-vinyl ester copolymer is produced by any known polymerization method, for example, solution polymerization, suspension polymerization, emulsion polymerization, etc., and the saponification of the ethylene-vinyl ester copolymer can also be performed by a known method.

  The EVOH resin (A) used in the resin composition of the present invention has an ethylene structural unit content of usually 20 to 60 mol%, preferably 25 to 50 mol%, more preferably 27, as measured based on ISO14663. -35 mol%. If the content of the ethylene structural unit is too small, the molding processability and the bending resistance of the resin composition tend to be lowered. On the other hand, if the ethylene structural unit content is too high, the proportion of OH groups contained in the polymer chain inevitably decreases, and the gas barrier properties tend to decrease. In particular, in the resin composition of the present invention, it is necessary to set the ethylene content in the above range because it is necessary to ensure high gas barrier properties based on the EVOH resin.

  As the vinyl ester monomer, vinyl acetate is typically used from the viewpoint of market availability and good impurity treatment efficiency during production. Other examples include aliphatic vinyl esters such as vinyl formate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl versatate, and benzoic acid. Examples thereof include aromatic vinyl esters such as vinyl acid, and are usually aliphatic vinyl esters having 3 to 20 carbon atoms, preferably 4 to 10 carbon atoms, and particularly preferably 4 to 7 carbon atoms. These are usually used alone, but may be used as a mixture of two or more if necessary.

  The saponification degree of the vinyl ester component is a value measured based on JIS K6726 (however, EVOH resin is a solution uniformly dissolved in water / methanol solvent), and is usually 95 mol% or more, more preferably. Is 95 to 100 mol%, more preferably 98 to 100 mol%. This is because as the saponification degree decreases, the gas barrier property tends to decrease.

  Further, the melt flow rate (MFR) of the EVOH resin (A) is usually 0.1 to 200 g / 10 minutes, preferably 0.5 to 100 g / 10 minutes, at 230 ° C. and a load of 2160 g. Particularly preferably, it is 1 to 40 g / 10 min. When the MFR value is too small, that is, when the melt viscosity is high, uniform melt-kneading with the block copolymer (B) becomes difficult, which causes a decrease in the dispersibility of the block copolymer (B). On the other hand, when the MFR value is too large, the melt viscosity tends to be low, and stable melt extrusion tends to be difficult.

The EVOH resin (A) used in the resin composition of the present invention may be a mixture of two or more different ethylene contents, saponification degrees, and MFRs, as long as the EVOH resin satisfies the above requirements. .
Moreover, as EVOH resin used for this invention, you may copolymerize a further small amount of copolymerizable monomers in a copolymer. Examples of the copolymerizable monomer include α-olefins such as propylene, isobutene, α-octene, α-dodecene and α-octadecene, 3-buten-1-ol, 4-penten-1-ol, and 3-butene-1. Hydroxyl group-containing α-olefins such as 2-diol, esterified products thereof, acylated products such as α-olefin derivatives such as acylated products, unsaturated carboxylic acids or salts thereof, partial alkyl esters, complete alkyl esters, nitriles, amides, Copolymerization of comonomers such as anhydrides, unsaturated sulfonic acids or salts thereof, vinyl silane compounds, vinyl chloride, and styrene is also acceptable. Furthermore, it may be “post-modified” such as urethanization, acetalization, cyanoethylation, oxyalkyleneation and the like.
In particular, an EVOH resin copolymerized with a hydroxy group-containing α-olefin is preferable in terms of good secondary formability such as stretching and vacuum / pressure forming, among which an EVOH resin having a 1,2-diol in the side chain. Is preferred.

  In the EVOH resin (A) used in the present invention, a compounding agent generally blended into the EVOH resin, for example, a heat stabilizer, an antioxidant, an antistatic agent, a colorant, an ultraviolet ray, within a range not inhibiting the effects of the present invention. Absorber, lubricant, plasticizer, light stabilizer, surfactant, antibacterial agent, desiccant, antiblocking agent, flame retardant, crosslinking agent, curing agent, foaming agent, crystal nucleating agent, antifogging agent, biodegradation additive An agent, a silane coupling agent, an oxygen absorbent and the like may be contained.

The heat stabilizer is an organic acid such as acetic acid, propionic acid, butyric acid, lauric acid, stearic acid, oleic acid, behenic acid, or an alkali thereof for the purpose of improving various physical properties such as heat stability during melt molding. Metal salts (sodium, potassium, etc.), alkaline earth metal salts (calcium, magnesium, etc.), salts such as zinc salts; or inorganic acids such as sulfuric acid, sulfurous acid, carbonic acid, phosphoric acid, boric acid, or alkali metals thereof Additives such as salts (such as sodium and potassium), alkaline earth metal salts (such as calcium and magnesium), and zinc salts may be added.
Of these, it is particularly preferable to add boron compounds, acetates and phosphates including acetic acid, boric acid and salts thereof.

  When acetic acid is added, the amount added is usually 0.001 to 1 part by weight, preferably 0.005 to 0.2 part by weight, particularly preferably 0.010 to 100 parts by weight of EVOH resin (A). 0.1 parts by weight. If the amount of acetic acid added is too small, the effect of acetic acid content tends not to be obtained sufficiently, and conversely if too large, it tends to be difficult to obtain a uniform film.

  Moreover, when adding a boron compound, the addition amount is 0.001-1 weight part normally by boron conversion (after ashing and analyzing by ICP emission spectrometry) with respect to 100 weight part of EVOH resin (A). Yes, preferably 0.002 to 0.2 parts by weight, particularly preferably 0.005 to 0.1 parts by weight. If the addition amount of the boron compound is too small, the effect of adding the boron compound may not be sufficiently obtained. Conversely, if the addition amount is too large, it tends to be difficult to obtain a uniform film.

  In addition, the amount of acetate and phosphate (including hydrogen phosphate) added is usually in metal conversion (after ashing and analyzed by ICP emission spectrometry) with respect to 100 parts by weight of EVOH resin (A). 0.0005 to 0.1 part by weight, preferably 0.001 to 0.05 part by weight, particularly preferably 0.002 to 0.03 part by weight. If the amount added is too small, the content effect may not be sufficiently obtained, while if too large, it tends to be difficult to obtain a uniform film. In addition, when adding 2 or more types of salts to EVOH resin (A), it is preferable that the total amount exists in the range of said addition amount.

The method for adding acetic acid, a boron compound, acetate, and phosphate to the EVOH resin (A) is not particularly limited, and i) a porous precipitate of the EVOH resin (A) having a water content of 20 to 80% by weight. A method of bringing the porous EVOH resin into contact with an aqueous solution of the additive and then drying; ii) adding the additive to a uniform solution (water / alcohol solution, etc.) of the EVOH resin (A) And then extruding into a coagulating liquid in the form of a strand, then cutting the obtained strand into pellets and further drying treatment; iii) Extruding after mixing the EVOH resin (A) and additives together A method of melt-kneading with a machine, etc .; iv) When producing EVOH resin (A), the alkali (sodium hydroxide, potassium hydroxide, etc.) used in the saponification step is neutralized with an organic acid such as acetic acid, How or adjusting the amount of the water washing treatment of the organic acid and by-product salts, such as acetic acid, and the like.
In order to obtain the effects of the present invention more remarkably, the method i) and ii), which are excellent in the dispersibility of the additive, and the method iv) are preferred when an organic acid and a salt thereof are contained.

[Styrenic thermoplastic elastomer (B) containing no polar groups]
The styrenic thermoplastic elastomer (B) that does not contain a polar group used in the present invention is composed of a polymer block (b1) of a vinyl aromatic monomer that usually becomes a hard segment, and an unsaturated hydrocarbon that is a rubber component that usually becomes a soft segment. A compound having a polymer block of a compound and / or a hydrogenated block (b2) thereof and generally known as a styrenic thermoplastic elastomer can be used. (In the present invention, such a styrenic thermoplastic elastomer (B) that does not contain a polar group may be referred to as a “block copolymer (B)”. The polar group contains a polar group described later. (The polar group in the styrenic thermoplastic elastomer (C) is shown.)

  The styrenic thermoplastic elastomer (B) containing no polar group used in the present invention contains a vinyl aromatic monomer polymer block (b1) and an unsaturated hydrocarbon compound polymer block or a hydrogenated block (b2) thereof. A diblock structure represented by b1-b2, a triblock structure represented by b1-b2-b1 or b2-b1-b2, a tetrablock structure represented by b1-b2-b1-b2, Alternatively, it may be a polyblock structure in which b1 and b2 are linearly bonded to each other. Among these, the diblock structure represented by b1-b2, the triblock structure represented by b1-b2-b1, and the tetrablock structure represented by b1-b2-b1-b2 have flexibility and mechanical properties. It is preferable from the point.

  Specific examples of the monomer constituting the vinyl aromatic polymer block (b1) include styrene, α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, and p-methylstyrene. , Styrene derivatives such as t-butylstyrene, 2,4-dimethylstyrene, 2,4,6-trimethylstyrene, monofluorostyrene, difluorostyrene, monochlorostyrene, dichlorostyrene, methoxystyrene; vinylnaphthalene, vinylanthracene, indene, And vinyl aromatic compounds such as acetonaphthylene. Furthermore, if necessary, other copolymerizable monomers such as 1-butene, pentene, hexene, butadiene, isoprene, and methyl vinyl ether may be used together with these vinyl aromatic monomers.

  Of the monomers constituting such a polymer block (b1), styrene and styrene derivatives are preferable, and styrene is particularly preferable.

  The polymer block (b1) of the vinyl aromatic monomer may be a homopolymer block of the above vinyl aromatic monomer or a copolymer block of two or more kinds of vinyl aromatic monomers.

As an unsaturated hydrocarbon compound which comprises the polymer block (b2) of the said unsaturated hydrocarbon compound, it is a C2-C10 unsaturated aliphatic hydrocarbon compound normally, Specifically, C2-C2 6 alkene, C 4-6 diene, and conjugated diene are mentioned. Among these, C 4-6 conjugated diene is preferably used.
Examples of the conjugated diene compound include isoprene, butadiene, hexadiene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, and the like. Examples of the diene include hexadiene. The aliphatic hydrocarbon polymer block (b2) made of a diene compound may be obtained as a result of hydrogenation of the polymer block made of the conjugated diene compound. Examples of the alkene include ethylene, propylene, n-butylene, and isobutylene. The aliphatic hydrocarbon polymer block (b2) composed of these alkenes may be obtained as a result of hydrogenation of the polymer block composed of the conjugated diene or diene.

  The aliphatic hydrocarbon polymer block (b2) may be a homopolymer block composed of one of the above unsaturated aliphatic hydrocarbon monomers, or a random copolymer block composed of two or more unsaturated aliphatic hydrocarbon monomers. It may be. The soft segment is preferably a polymer block of conjugated diene or a hydrogenated block thereof.

  The hydrogenated block of the aliphatic hydrocarbon polymer block is formed by hydrogenation of a part or all of unsaturated bonds in the polymer block of diene and / or conjugated diene. For example, a polybutadiene block becomes an ethylene / butylene polymer block or a butadiene / butylene polymer block by hydrogenation. The polyisoprene block becomes an ethylene / propylene polymer block or the like by hydrogenation. Hydrogenation can be performed by a known method, and a specific vinyl bond moiety may be selectively hydrogenated.

  The block copolymer (B) used in the present invention is a combination of the vinyl aromatic monomer polymer block (b1) and the unsaturated hydrocarbon compound polymer block (b2), and the block structure is not particularly limited. Examples thereof include radial teleblock copolymers, multiblock copolymers, bimodal copolymers, and tapered block copolymers.

  The content of the vinyl aromatic structural unit (polymer block b1) in the block copolymer (B) is usually 5 to 50% by weight, preferably 10 to 40% by weight, more preferably 10 to 35% by weight. . When the content rate of a vinyl aromatic structural unit is moderately large, the difference of a refractive index with EVOH resin (A) becomes small, and there exists a tendency for transparency to improve. However, when the content rate of a vinyl aromatic structural unit is too large, there exists a tendency for the softness | flexibility of a block copolymer (B) itself to fall and to become difficult to obtain the bending resistance improvement effect of a resin composition. The smaller the vinyl aromatic structural unit content, the better the flex resistance. However, if the content is too small, the transparency of the film decreases and the compatibility with the EVOH resin (A) decreases. As a result, it becomes difficult to obtain the effect of improving the bending resistance.

  The content of the unsaturated hydrocarbon compound polymer block and / or the hydrogenated block thereof (polymer block b2) in the block copolymer (B) is usually 50 to 95% by weight, preferably 60 to 90%. % By weight, more preferably 65 to 90% by weight.

The polymer blocks (b1) and (b2) may be random copolymer blocks obtained by copolymerizing other copolymerizable monomers as necessary. Other copolymerization monomers are, for example, unsaturated hydrocarbons having 2 to 3 carbon atoms such as ethylene and propylene.
However, when other copolymerizable monomer is included, the content of the other copolymerizable monomer in each polymer block is preferably 10% by weight or less of each polymer block weight, and may be 5% by weight or less. More preferred.

  Specific examples of the block copolymer (B) having the above-described structure include styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), and hydrogenation of SBS. Block copolymer (SEBS), SIS hydrogenated block copolymer (SEPS), block copolymer (SBBS) in which vinyl bond part of butadiene block of SBS is hydrogenated, styrene-isobutylene-styrene triblock copolymer (SIBS), styrene-ethylene-butylene-crystalline polyolefin block copolymer (SEBC), and the like. Among these, SEBS which is excellent in thermal stability and weather resistance is preferably used. In SEBS, a polybutadiene block is converted to an ethylene / butylene copolymer block by hydrogenation.

The melt flow rate (MFR) of the block copolymer (B) is usually 0.01 to 200 g / 10 minutes, preferably 0.1 to 100 g / 10 minutes, at 230 ° C. and a load of 2160 g. It is preferably 1 to 50 g / 10 minutes, and particularly preferably 3 to 15 g / 10 minutes.
The closer the melt viscosity of the EVOH resin (A) and the block copolymer (B) are, the easier the melt kneading becomes and the resin composition in which the block copolymer (B) is uniformly dispersed in the EVOH resin Is easily obtained, and as a result, a resin composition excellent in bending resistance and transparency is easily obtained. Specifically, the MFR ratio (EVOH resin (A) / block copolymer (B)) measured under the conditions of 230 ° C. and a load of 2160 g is usually 0.1 to 10, preferably 0.5 to 4, and more. Preferably it is 0.7-3.

  As such a block copolymer (B), a commercially available product may be used. Examples of commercially available products include “Dynalon”, “JSR-TR”, and “JSR-SIS” manufactured by JSR; “Septon” and “Hypler” manufactured by Kuraray; “Quintac” manufactured by Nippon Zeon, Asahi Kasei “Tuftec” “Tufprene” manufactured by Clayton Polymer; “Kraton G” “Kraton D” “Cariflex TR” manufactured by Clayton Polymer; “Electrified STR” manufactured by Denki Kagaku; “Asaprene T” manufactured by Nippon Elastomer

[Styrenic thermoplastic elastomer containing polar groups (C)]
The styrenic thermoplastic elastomer (C) containing a polar group used in the present invention is a polymer block (c1) composed of an aromatic vinyl monomer unit and a polymer block obtained by polymerizing an unsaturated hydrocarbon compound or hydrogenation thereof. It is a block copolymer having a block (c2), and further a block copolymer having a polar group.

Specific examples of such a polar group include a carboxyl group, an amino group, an alkoxyl group, a hydroxyl group, an amide group, and an epoxy group. The carboxyl group includes an acid anhydride group that is a derivative of the carboxyl group. (In the present invention, the styrenic thermoplastic elastomer (C) containing such a polar group may be referred to as “modified block copolymer (C)”.)
The modified block copolymer (C) preferably has an appropriate reactivity with the EVOH resin (A). From this point, the modified block copolymer (C) has at least one polar group selected from the group consisting of a carboxyl group and an amino group. A block copolymer (C) is preferable, and a modified block copolymer (C) having a carboxyl group is more preferable.

The unsaturated hydrocarbon compound used in the polymer block of the aromatic vinyl or unsaturated hydrocarbon compound used in the polymer block of the aromatic vinyl constituting the block copolymer of the modified block copolymer (C) includes the above-mentioned block What was used with the copolymer (B) can be used.
The block copolymer of the modified block copolymer (C) and the block copolymer (B) may have the same monomer structure (ie, b1 and c1, b2 and c2) and block structure. , May be different.

  The modified block copolymer (C) having a polar group has an affinity for the EVOH resin (A) having a hydroxyl group that is a polar group. On the other hand, since the block copolymer portion of the modified block copolymer (C) has an affinity for the block copolymer (B), the modified block copolymer (C) is combined with the EVOH resin (A) and the block copolymer. It can serve as a compatibilizing agent for the polymer (B).

  In the case of carboxyl group modification, examples of the compound used for modification include unsaturated carboxylic acids or derivatives thereof, for example, α, β-unsaturated carboxylic acid and α, β-unsaturated carboxylic acid anhydride. For example, specifically, α, β-unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid; α, β-unsaturated dicarboxylic acids such as maleic acid, succinic acid, itaconic acid, and phthalic acid; glycidyl acrylate Α, β-unsaturated monocarboxylic acid esters such as glycidyl methacrylate, hydroxyethyl acrylate and hydroxymethyl methacrylate; α, β-unsaturated dicarboxylic acid anhydrides such as maleic anhydride, succinic anhydride, itaconic anhydride and phthalic anhydride Things can be mentioned.

  In the case of amino group modification, the compounds used for modification include 3-lithio-1- [N, N-bis (trimethylsilyl)] aminopropane, 2-lithio-1- [N, N-bis (trimethylsilyl)] aminoethane. , 3-lithio-2,2-dimethyl-1- [N, N-bis (trimethylsilyl)] aminopropane and the like, and examples of the unsaturated amine or a derivative thereof include vinylamine.

  In the case of alkoxyl group modification, examples of the compound used for modification include alkoxysilanes such as tetraethoxysilane, tetramethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, and dimethyldiphenoxysilane. Specific examples of the derivatives include alkyl vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, isobutyl vinyl ether, pentyl vinyl ether, and hexyl vinyl ether.

  In the case of hydroxyl group modification, examples of the compound used for modification include unsaturated alcohols or derivatives thereof, and specific examples thereof include 3-buten-1-ol, 4-penten-1-ol, and 5-hexene-1. -All etc. are mentioned.

  In the case of amide group modification, examples of the compound used for modification include unsaturated amides or derivatives thereof, such as N-vinylformamide, N-vinylacetamide, N-methyl-N-vinylformamide, N -Methyl-N-vinylacetamide, diacetone acrylamide, acrylamide, methacrylamide, polyoxyethylene (meth) acrylamide, polyoxyalkylene (meth) acrylamide such as polyoxypropylene (meth) acrylamide, and the like.

  In the case of epoxy group modification, examples of the compound used for modification include unsaturated epoxides or derivatives thereof, such as vinyl epoxides.

  Modification using the polar group-containing compound as described above includes, for example, a method of copolymerizing a part of the constituent monomers of the block copolymer in place of the polar group-containing compound, and a polar group-containing compound in a part of the side chain It is carried out by a method of introducing by radical addition or the like, or a method of post-modifying the block copolymer.

  The content of the polar group in the modified block copolymer (C) is usually 1.0 × 10 −3 to 1 mmol / g, preferably 5.0 × 10 −3 to 0.5 mmol / g, more preferably Is 1.0 × 10 −2 to 0.2 mmol / g, more preferably 1.0 × 10 −2 to 0.1 mmol / g. If the polar group content is too large, the affinity with the EVOH resin becomes too high, and a highly polymerized product is likely to be generated, and the MFR of the resin composition tends to decrease and the moldability tends to be insufficient. is there. In addition, viscosity deviation occurs in the resin composition, and when the resin composition is used as a film, streaks are likely to occur, and the bending resistance tends to be lowered.

In particular, when the modified block copolymer (C) has a carboxyl group, the content of the carboxyl group is such that the acid value measured by a titration method is usually 20 mgCH3ONa / g or less, preferably 1 to 15 mgCH3ONa / g. More preferably, it is 1 to 5 mg CH3ONa / g.
If the acid value is too high, the number of reaction points with the EVOH resin increases, so that a highly polymerized product is likely to be generated, and the MFR of the resin composition tends to decrease and the moldability tends to be insufficient. In addition, the occurrence of a highly polymerized product causes uneven viscosity in the resin composition, and when the resin composition is used as a film, streaks are likely to occur, and the flex resistance tends to decrease.

The melt flow rate (MFR) of the modified block copolymer (C) is usually 0.01 to 200 g / 10 minutes at 230 ° C. and a load of 2160 g, preferably 0.1 to 100 g / 10. Minute, preferably 1 to 50 g / 10 minutes, more preferably 2 to 15 g / 10 minutes.
The closer the melt viscosity of the EVOH resin (A) is to that of the modified block copolymer (C), the easier the melt kneading and the easier it is to obtain a resin composition with excellent flex resistance and transparency. Specifically, the MFR ratio (EVOH resin (A) / modified block copolymer (C)) measured at 230 ° C. under a load of 2160 g is usually 0.1 to 10, preferably 0.5 to 4. 0, more preferably 0.7 to 3.0.
The melt viscosity ratio between the block copolymer (B) and the modified block copolymer (C) is specifically, for example, the MFR ratio (block copolymer measured at 230 ° C. under a load of 2160 g). (B) / modified block copolymer (C)) is usually 0.1 to 10, preferably 0.5 to 4.0, more preferably 0.7 to 3.0.

  A commercial item may be used as this modified block copolymer (C). Examples of commercially available products include “Tough Tech” M series manufactured by Asahi Kasei Corporation, “Kraton” FG series manufactured by Kraton Polymer, and “f-Dynalon” series manufactured by JSR.

[Hydrocarbon resin (D)]
The hydrocarbon resin as component D used in the present invention is added as a dispersion aid and has a hydrocarbon number average molecular weight of 100 to 3000 and a softening point of 60 ° C. or higher and lower than 170 ° C. (Hereinafter, it may be simply referred to as “hydrocarbon resin (D)”). Such hydrocarbon resins usually belong to thermoplastic resins that are liquid or solid at room temperature.

  Specific examples of the D component include rosin resins (rosin, hydrogenated rosin, disproportionated rosin, modified rosin such as polymerized rosin, glycerin ester of modified rosin and rosin ester such as pentaerythritol ester) and terpene series. Natural hydrocarbon resins such as resins (terpene resins, aromatic modified terpene resins, hydrogenated terpene resins, terpene phenol resins); petroleum resins, coumarone indene resins, phenolic resins (alkylphenol resins, rosin-modified phenol resins, etc.), Examples thereof include synthetic hydrocarbon resins such as styrene resins and xylene resins.

  The above petroleum resin means one obtained by polymerizing a fraction containing an unsaturated hydrocarbon monomer by-produced by thermal decomposition of petroleum naphtha or the like, and specifically, an aliphatic petroleum resin (C5 petroleum resin). Aromatic petroleum resins (C9 petroleum resins), aliphatic / aromatic petroleum resins (C5 / C9 petroleum resins), and alicyclic petroleum resins (hydrogenated petroleum resins).

  Aliphatic petroleum resin (C5 petroleum resin) is a synthetic resin obtained by polymerizing the refined component of C5 fraction of petroleum naphtha cracked oil. Specific examples include Quinton 100 series (manufactured by ZEON Corporation). ), Escorez 1000 series (manufactured by ExxonMobil).

  Aromatic petroleum resin (C9 petroleum resin) is a synthetic resin obtained by polymerizing the refined components of C9 fraction of petroleum naphtha cracked oil. Specific examples include Petol (manufactured by Tosoh Corporation), Stone neopolymer (manufactured by Nippon Oil Corporation).

  Aliphatic / aromatic petroleum resin (C5 / C9 petroleum resin) is a synthetic resin obtained by copolymerizing the raw material blended with the above C5 fraction and C9 fraction. Examples include Tuck (manufactured by Tosoh Corporation), Toho High Resin (manufactured by Toho Chemical Industry Co., Ltd.), Quinton 100 series (manufactured by ZEON Corporation), and Scollets 2000 series (manufactured by ExxonMobil Corporation).

The alicyclic petroleum resin contains dicyclopentadiene extracted from hydrogenated petroleum resin obtained by hydrogenating the above aromatic petroleum resin or aliphatic / aromatic petroleum resin and C5 fraction. There is a synthetic resin obtained by synthesizing the main raw material.
Among them, the above-mentioned aromatic petroleum resins or hydrogenated petroleum resins obtained by hydrogenation of aliphatic / aromatic petroleum resins are representative. As a specific example, Alcon (manufactured by Arakawa Chemical Industries) , Imabe (manufactured by Idemitsu Kosan Co., Ltd.), Escorez 5000 series (manufactured by ExxonMobil Corp.), and the like. In the case of such a hydrogenated petroleum resin, the polarity of the resin differs depending on the hydrogenation rate, and there are mainly two types: a fully hydrogenated type with a hydrogenation rate of 90% or more and a partially hydrogenated type with a hydrogenation rate of less than 90%. being classified. Specific examples of the former include Alcon P grade (manufactured by Arakawa Chemical Co., Ltd.), Imabe P type (manufactured by Idemitsu Kosan Co., Ltd.) and the like. Specific examples of the latter include Alcon M grade (manufactured by Arakawa Chemical Industrial Co., Ltd.), Imarve S type (made by Idemitsu Kosan Co., Ltd.) and the like.

  As an alicyclic petroleum resin obtained by a method other than hydrogenation, specific examples of synthetic resins obtained by synthesizing dicyclopentadiene extracted from a C5 fraction as a main raw material include the Quinton 1000 series (Japan) Zeon) and Marcaretz M series (Maruzen Petrochemical).

In the present invention, it is preferable to use a petroleum resin from the viewpoint of improving the appearance and odorlessness such as transparency and color tone of the resin composition, more preferably using an alicyclic petroleum resin, especially water. It is preferable to use additive petroleum resin.
Further, the hydrogenation rate of the hydrogenated petroleum resin is not particularly limited, but considering the affinity with the hydrogenated block copolymer (B) such as SEBS or SEPS having a low polarity, it is a completely hydrogenated type. It is preferable to use a hydrogenated petroleum resin.

The number average molecular weight of component D is usually 100 to 3000, preferably 300 or more and less than 1500, and particularly preferably 400 or more and less than 1000. If the number average molecular weight is too small, it is liable to become liquid at the raw material charging part during melt mixing, and particularly when the liquid is low in viscosity, it tends to cause poor mixing, and the film transparency may be lowered due to poor dispersion, or D There is a possibility that the components are easily eluted from the molded product. Also, if the number average molecular weight is too large, it tends to be difficult to penetrate into the B component aggregates as a fluid during melt-kneading, and it becomes easy to separate from the EVOH resin due to the property of the D component, which is oleophilic. There is a risk of causing appearance defects such as spears and streaks.
The number average molecular weight can be calculated from a polystyrene-converted value obtained by gel permeation chromatography (GPC) measurement.

  The softening point of component D is usually 60 ° C. or higher and lower than 170 ° C., preferably 95 ° C. or higher and lower than 160 ° C., particularly preferably 120 ° C. or higher and lower than 150 ° C. When the softening point is too low, it tends to become a low-viscosity liquid in the raw material charging part during melt mixing, and cannot fully serve as a dispersion aid for the D component. As a result, due to poor dispersion of the B component, it is difficult to sufficiently improve the flex resistance and transparency. In addition, the problem that the D component easily elutes from the molded product is likely to occur. If the softening point is too high, the unmelted portion of the D component remains during melt mixing, the function as a dispersion aid is reduced, and sufficient flex resistance and transparency may not be obtained. Furthermore, foreign matters such as fish eyes may be generated in the film molding due to the remaining unmelted portion.

  In addition, as a measuring method of a softening point, the method based on JISK2207 (ring ball method) can be used.

As the hue of the D component, the Gardner number is usually 3 or less, preferably 2 or less, particularly preferably 1 or less. When the Gardner number exceeds 3, the yellowness of the resin composition becomes strong and the appearance characteristics may be deteriorated.
In the case of hydrogenated petroleum resin, the Hazen number is usually 200 or less, preferably 150 or less, particularly preferably 100 or less. When a Hazen number of 200 or less is used, a colorless and transparent resin composition having excellent appearance characteristics can be obtained.
In addition, as a measuring method of a hue, the method based on JIS K0071-1 (Hazen number) and JIS K0071-2 (Gardner number) can be used.

  Examples of the form of the component D at normal temperature include, but are not particularly limited to, powder, lump, flake, pellet (granular), and liquid. From the viewpoints of workability and meterability during mixing, flakes and pellets are preferable, and pellets are particularly preferable.

  The D component as described above not only has the effect that the B component can be finely dispersed in the sea of the EVOH resin, but also liquefies during melt molding, thereby reducing the viscosity of the composition during melting (MFR). It is also possible to increase the value). This is considered to bring about the following effects. That is, since the polar group-containing compound used in the polar group-modified vinyl polymer that is the C component, particularly the carboxyl group and the hydroxyl group in the EVOH resin can react, both functional groups react in the melt-kneading process. A degree of polymerization may be produced. The production of this highly polymerized product increases the melt viscosity, and shear heat generation is likely to occur in the extruder, and the highly polymerized product further increases, resulting in poor appearance such as streaks and fish eyes in the film molded product. May be incurred. However, if it becomes possible to reduce the viscosity of the composition at the time of melting by blending the D component, it is considered that the suppression of shearing heat generation and the generation of highly polymerized products are suppressed, and as a result, it can contribute effectively from the viewpoint of quality improvement. It is done.

  The inorganic fine particles (E) used in the present invention are not particularly limited, and examples thereof include silicon oxide, aluminum oxide, zirconium oxide, magnesium oxide, cerium oxide, tungsten oxide, molybdenum oxide, and composites thereof. At least one of these can be selected. Further, the particle diameter of these inorganic fine particles is preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm. If the particle diameter is less than 0.1 μm, the effect of improving blocking resistance is poor, and conversely exceeds 10 μm. In addition, gels, fish eyes and the like are generated in the molded product, resulting in an unfavorable appearance. Among the inorganic fine particles, silicon oxide (silicic acid) or silicon oxide-magnesium oxide (magnesium silicate) is preferably used from the viewpoint of compatibility with the EVOH resin.

[Combination ratio]
One of the features of the present invention is that the components (A) to (E) are blended in a specific ratio, and it is particularly important that the EVOH resin (A) exists as a matrix.
The EVOH resin is a main component, and the content in the entire resin composition is usually 60 to 99% by weight, preferably 65 to 90% by weight, more preferably 65 to 85% by weight, and further preferably 70 to 80% by weight. %.

The total sum of the components (B) and (C) relative to the EVOH resin (A) is usually greater than 50/50 and not more than 99/1 as a weight ratio (A) / [(B) + (C)], preferably 60/40 to 90/10, particularly preferably 70/30 to 85/15.
Moreover, the total content of the aromatic vinyl moiety of the block copolymer (B) and the modified block copolymer (C) with respect to the total weight of the resin composition of the present invention is usually 0.1 to 50% by weight, It is preferably 1 to 30% by weight, particularly preferably 2 to 20% by weight, particularly preferably 2 to 15% by weight.

  In the resin composition of the present invention, the weight ratio (A / B) of the EVOH resin (A) and the block copolymer (B) is usually 70/30 to 99/1, preferably 70/30 to 85/15, More preferably, it is 75 / 25-85 / 15. The EVOH resin (A) is a main component, and the EVOH resin (A) is present as a matrix by blending at a ratio twice or more that of the block copolymer (B), and the gas barrier inherent in the EVOH resin (A). Sex can be maintained.

The weight ratio (C / B) of the modified block copolymer (C) to the block copolymer (B) is usually 0.01 to 10, although it depends on the modification rate of the modified block copolymer (C). , Preferably 0.01 to 1, more preferably 0.05 to 0.8, still more preferably 0.1 to 0.5, particularly preferably 0.1 to 0.25, particularly preferably. It is 0.12-0.23.
In the resin composition of the present invention, the modified block copolymer (C) is used as a compatibilizer between the EVOH resin (A) and the block copolymer (B), and the blending ratio is adjusted as described above. As a result, a large number of small islands of the block copolymer (B) can be dispersed throughout the EVOH resin (A) as a matrix.

When the blending ratio (C / B) is too low, the compatibility between the EVOH resin (A) component and the block copolymer (B) component is insufficient, and thus the EVOH resin (A) component which is the main component. Formation of the continuous layer of the matrix becomes incomplete, and there is a risk that the bending resistance is lowered due to insufficient film toughness and the gas barrier property is lowered due to defects in the EVOH resin continuous layer.
If the blending ratio (C / B) is too high, it is difficult to obtain an effect of improving the bending resistance, but high polymerization is achieved by increasing the affinity between the EVOH resin (A) and the modified block copolymer (C). A refined product is likely to be generated, and the MFR of the resin composition tends to decrease, and the moldability tends to decrease. Moreover, generation | occurrence | production of highly polymerized substance causes the bias | inclination of the viscosity in a resin composition, it becomes easy to generate | occur | produce a streak in the film obtained by shaping | molding, and there exists a tendency for the bending resistance improvement effect to be impaired as a result. In addition, the resin composition is likely to be colored yellow.

In the present invention, it is also one of the features that a specific small amount of the component (D) and the component (E) is blended with the system in which the component (A), the component (B), and the component (C) are present.
The content of component (D) is usually 0.5 to 7.5% by weight, preferably 1 to 6% by weight, more preferably 2 to 2%, based on the total amount of components (A) to (D). 5% by weight. When there are too few compounding quantities of D component which is a dispersion | distribution adjuvant, it becomes difficult to obtain the compounding effect of (D). On the other hand, when it is too much, excessive hydrocarbon-based resin (D) is rejected, which may cause appearance defects such as film streaks and eyes.

  The content of the component (E) is usually 0.001 to 5% by weight, preferably 0.01 to 5% by weight, more preferably 0.05 to the total amount of the components (A) to (E). 1% by weight. When there are too few compounding quantities of E component, it becomes difficult to acquire the effect of blocking resistance. On the other hand, when too large, there exists a possibility that a softness | flexibility may fall.

  In the resin composition of the present invention blended at the blending ratio as described above, the block copolymer (B) is uniformly dispersed using the EVOH resin (A) as a matrix, and is excellent in melt moldability. Specifically, the melt flow rate (MFR) at 210 ° C. and 2160 g is usually 0.5 to 30 g / 10 min, preferably 2 to 20 g / 10 min, particularly preferably 2.5 to 15 g / min. 10 minutes, particularly preferably 3.0 to 5 g / 10 minutes. When the MFR as the resin composition falls within the above range, when supplied to an extruder, a discharge amount suitable for melt molding is obtained, and a film with less streaking and excellent appearance can be obtained.

[Other ingredients]
In the resin composition of the present invention, the EVOH resin (A), the block copolymer (B), and the modified block copolymer are within a range not inhibiting the effects of the present invention (for example, 2% by weight or less of the resin composition). In addition to the coalescence (C), an antioxidant, a lubricant, an antistatic agent, a colorant, an ultraviolet absorber, a plasticizer, a heat stabilizer, a light stabilizer, a surfactant, an antibacterial agent, and a desiccant as necessary. , An anti-blocking agent, a flame retardant, a crosslinking agent, a curing agent, a foaming agent, a crystal nucleating agent, an antifogging agent, an additive for biodegradation, a silane coupling agent, an oxygen absorber, etc. .

[Preparation of resin composition and molded product (single layer film)]
The resin composition of the present invention can be prepared by mixing the above components. Examples of such mixing methods include dry blending, melt mixing, and solution mixing. From the viewpoint of productivity, the melt mixing method is preferable.
As the melt mixing method, each component can be dry blended and then melted and mixed. For example, a known kneading apparatus such as a kneader ruder, an extruder, a mixing roll, a Banbury mixer, or a plast mill can be used. However, in general, it is industrially preferable to use a single-screw or twin-screw extruder, and it is also preferable to provide a vent suction device, a gear pump device, a screen device or the like as necessary.

  The melt kneading temperature is usually in the range of 170 to 250 ° C., preferably 180 to 240 ° C., particularly preferably 180 to 230 ° C. as the set temperature of the extruder and the die. If the temperature is too low, the resin tends to be in an unmelted state and the processing state tends to become unstable. If the temperature is too high, the resin composition is thermally deteriorated, resulting in the quality of the obtained molded product. Tend to decrease.

  The resin composition of the present invention having the above composition is excellent in bending resistance while maintaining the gas barrier properties inherent to the EVOH resin (A). Specifically, the oxygen gas permeation amount in a film having a thickness of 30 μm is usually 10 cc / m 2 · day · atm or less at 23 ° C. and 65% RH, and even if twisted 500 times with a gelbo flex tester, The generation amount of pinholes in an area of 476 cm <2> is usually 10 or less, and the MFR (210 [deg.] C., 2160 g) is usually 0.5-30 g / 10 minutes.

That is, the bending resistance in the present invention is not resistance to instantaneous external force such as impact, but resistance to fatigue gradually accumulated over a long time. One of such resistances is obtained by absorbing energy generated by bending and reducing accumulated fatigue.
In the resin composition of the present invention, the block copolymer (B), which is a soft component, plays a role of fatigue absorption, and further includes a styrenic thermoplastic elastomer (C) containing a polar group and a number average molecular weight of 100 to 3000. In addition, by using together the hydrocarbon resin (D) having a softening point of 60 ° C. or more and less than 170 ° C., the component (B) is uniformly and finely dispersed to further improve gas barrier properties and molding processability. It is considered that the effect of excellent transparency can be obtained.

<Multilayer structure>
The multilayer structure of the present invention is a multilayer structure having at least one layer composed of the resin composition of the present invention (hereinafter simply referred to as “resin composition layer”).
Although it does not specifically limit as resin which comprises layers other than the resin composition layer which comprises the multilayer structure of this invention, Thermoplastic resins other than EVOH resin are mentioned. For example, linear low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer, ionomer, ethylene-propylene copolymer, ethylene-α-olefin (carbon number) 4-20 α-olefin) copolymer, ethylene-acrylate copolymer, polypropylene, propylene-α-olefin (α-olefin having 4 to 20 carbon atoms) copolymer, polybutene, polypentene, and other olefins. Homologous polyolefin resins, polystyrene resins, polyesters, polyamides, copolymers such as homo- or copolymers, cyclic polyolefins, or those obtained by graft-modifying homo- or copolymers of these olefins with unsaturated carboxylic acids or esters thereof Polyamide, polyvinyl chloride, polyvinyl chloride Alkylidene, acrylic resin, vinyl ester resin, polyester elastomers, polyurethane elastomers, chlorinated polyethylene, layer is composed of thermoplastic resin such as chlorinated polypropylene. In addition to these resins, it may be a multilayer structure combined with paper, metal foil, uniaxial or biaxially stretched plastic film or sheet, woven fabric, non-woven fabric, metal wool, wood surface, aluminum or silica deposition. . Among these, polyolefin resins are preferable from the viewpoint of mechanical strength and moldability, and polyethylene and polypropylene are particularly preferable.

  Among these, a multilayer structure having a structure in which a thermoplastic resin layer having an excellent water barrier property is used as an outer surface layer and a resin composition layer is used as an intermediate layer is preferably used for packaging films and packaging containers having gas barrier properties. It is done. The thermoplastic resin having excellent water barrier properties is preferably a polyolefin resin, and particularly preferably polyethylene or polypropylene.

The method for producing the multilayer structure is roughly divided into a method in which the resin composition is melted (melt molding method), a method in which the resin composition is dissolved in a solvent (for example, solution coating method), and the like. Is done. Among these, the melt molding method is preferable from the viewpoint of productivity.
Specifically, for example, a method of melt-extruding a thermoplastic resin to a molded article (for example, a film or a sheet) of an EVOH resin composition, a method of melt-extruding a resin composition layer to a substrate such as a thermoplastic resin, a resin composition The method of coextruding a physical layer and a thermoplastic resin layer is mentioned, In detail, T-die extrusion, inflation extrusion, blow molding, profile extrusion, etc. are employ | adopted.
Furthermore, the EVOH resin composition film and a substrate such as a thermoplastic resin film are dry laminated using a known adhesive such as an organic titanium compound, an isocyanate compound, a polyethyleneimine compound, a polyester compound, or a polyurethane compound. And a method of laminating with an adhesive resin layer interposed therebetween.
In some cases, a co-injection method can also be employed.

  The adhesive resin constituting the adhesive resin layer is not particularly limited, and various resins can be used. Generally, an unsaturated carboxylic acid or an anhydride thereof is an olefin polymer (the above-mentioned broad sense). And a modified olefin polymer containing a carboxyl group obtained by chemically bonding to a polyolefin resin) by an addition reaction or a graft reaction. Specifically, maleic anhydride graft-modified polyethylene, anhydrous Preferred examples include one or a mixture of two or more selected from maleic acid graft-modified polypropylene, maleic anhydride graft-modified ethylene-ethyl acrylate copolymer, maleic anhydride graft-modified ethylene-vinyl acetate copolymer, and the like. It is done.

  As described above, the multilayer structure of the present invention is not particularly limited as long as it includes at least one resin composition layer according to the present invention, and its structure is not particularly limited. In order to prevent this, the resin composition layer is preferably an intermediate layer.

The layer structure of the multilayer structure is usually 3 when the resin composition layer is a (a1, a2,...) And the thermoplastic resin layer other than the EVOH resin is b (b1, b2,...). 20 layers, preferably 3 to 15 layers, particularly preferably 3 to 10 layers. For example, specifically, b / a / b, a / b / a, a1 / a2 / b, a / b1 / b2, b2 / b1 / a / b1 / b2, b2 / b1 / a / b1 / a / Arbitrary combinations such as b1 / b2 are possible.
When a recycling layer containing a mixture of a resin composition and a thermoplastic resin other than the EVOH resin, obtained by remelt molding an end portion or defective product generated in the process of manufacturing the multilayer structure, is R. B / a / R, R / b / a, b / R / a / b, b / R / a / R / b, b / a / R / a / b, b / R / a / R / a / R / b or the like is also possible.
Further, a known adhesive resin may be used between the layers of the multilayer structure.

  Among these, in order to prevent the gas barrier performance of the resin composition layer from being lowered, a multilayer structure in which the resin composition layer serves as an intermediate layer is most preferable so that moisture can be prevented from passing through the resin composition layer. For example, specifically, a multilayer structure having a thermoplastic resin layer / adhesive resin layer / resin composition layer / adhesive resin layer / thermoplastic resin layer as a structural unit is most preferable.

  The thickness of the multilayer structure of the present invention is usually 1-1500 μm, preferably 1-1000 μm, more preferably 10-700 μm. Moreover, the thickness of the thermoplastic resin layer in the multilayer structure is not particularly limited, but usually 0.1 to 1000 μm and 1 to 500 μm are preferable. Although the thickness of a resin composition layer is not specifically limited, Usually, 0.1-500 micrometers, Preferably it is 1-100 micrometers. The thickness of the adhesive resin layer is not particularly limited, but is usually 0.1 to 250 μm, preferably 0.1 to 100 μm.

  The thickness ratio of the thermoplastic resin layer / resin composition layer is usually more than 1 to 30, preferably 2 to 30, in the ratio of the thickest layers when there are a plurality of layers. The thickness ratio of the conductive resin layer / resin composition layer is usually 0.1 to 2, preferably 0.1 to 1.

  As described above, the multilayer structure of the present invention is a multilayer structure that is simply laminated with another thermoplastic resin or a base material, but may be stretched.

  For stretching, a known stretching method can be used. Examples thereof include uniaxial stretching and biaxial stretching. In the case of biaxial stretching, both a simultaneous biaxial stretching method and a sequential biaxial stretching method can be employed. The stretching temperature is the temperature of the multilayer structure (the temperature in the vicinity of the multilayer structure) and is usually selected from the range of about 40 to 170 ° C, preferably about 60 to 160 ° C. A draw ratio is 2-50 times normally by an area ratio, Preferably it is 2-20 times. Further, heat setting may be performed after the stretching treatment. Thereby, the dimensional stability of a stretched film can be improved. The heat setting can be carried out by known means, for example, by heating at 80 to 180 ° C., preferably 100 to 165 ° C., usually for about 2 to 600 seconds while maintaining the stretched film.

  The multilayer structure of the present invention thus obtained is processed into, for example, a tube shape or a bag shape, food such as mirin, soy sauce, sauce, noodle soup, edible oil, wine, juice, milk, mineral water, sake. Wide range of uses as packaging materials for various liquids such as beverages such as shochu, coffee, tea, pharmaceuticals, cosmetics, sodium hypochlorite, industrial chemicals such as developer and battery fluid, agricultural chemicals such as liquid fertilizer, and detergents It is possible to use. Among these, it is preferable to use as a bag-like container as a liquid container, and it is particularly preferable to use it as a bag for a bag-in-box.

The bag-in-box is a container in which a foldable plastic thin inner container is combined with an outer box (bag-in-box) having stackability, portability, inner container protection, and printability.
The base material for the exterior may be plastic or metal in addition to paper or cardboard, and examples of the shape include a box, a carton (square, rectangular parallelepiped), and a drum (cylinder).

  In some cases, it is also possible to obtain cups or tray-like multilayer containers from the multilayer structure of the present invention. In that case, usually a drawing method is employed, and specific examples include a vacuum forming method, a pressure forming method, a vacuum pressure forming method, a plug assist type vacuum forming method. Furthermore, when a tube or bottle-shaped multilayer container is obtained from a multilayer parison (a hollow tubular preform before blow), a blow molding method is adopted. Specifically, an extrusion blow molding method (double-head type, mold transfer type, Parison shift type, rotary type, accumulator type, horizontal parison type, etc.), cold parison type blow molding method, injection blow molding method, biaxial stretch blow molding method (extrusion type cold parison biaxial stretch blow molding method, injection type cold) Parison biaxial stretch blow molding method, injection molding inline biaxial stretch blow molding method, etc.). The obtained laminate is subjected to heat treatment, cooling treatment, rolling treatment, printing treatment, dry lamination treatment, solution or melt coating treatment, bag making processing, deep drawing processing, box processing, tube processing, split processing, etc. as necessary. Can do.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the description of the examples unless it exceeds the gist.
In the examples, “parts” means weight basis unless otherwise specified.

Example 1
[Production of resin composition pellets and film]
(EVOH resin composition 1)
As the EVOH resin (A), EVOH (Soeneol “DT2904RB” manufactured by Nippon Gosei Kagaku Co., Ltd. with ethylene content 29 mol%, saponification degree = 99.6 mol%, MFR = 4 g / 10 min (210 ° C., 2160 g)) is used. It was.

As the block copolymer (B), SEBS (styrene content 30% by weight, MFR = 5 (230 ° C., 2160 g), Tuftec “H1041” manufactured by Asahi Kasei Chemicals) is used, and as the modified block copolymer (C) , Modified SEBS (styrene content 30% by weight, MFR = 4.5 (230 ° C., 2160 g), polar group modified amount 1.9 × 10 −2 (mmol / g), Tuftec “M1911” manufactured by Asahi Kasei Chemicals Co., Ltd. was used. Is a hydrogenated block copolymer of SBS.
Modified SEBS contains a carboxyl group as a polar group in SEBS.

  The hydrocarbon resin (D) having a number average molecular weight of 100 to 3000 and a softening point of 60 ° C. or more and less than 170 ° C. is a hydrocarbon resin (softening point 125 ° C., Hazen number 30, number average molecular weight 750 Arakawa Chemical Industries "Arcon P125") was used. The softening point is a measured value based on JIS K2207 (ring and ball method), the Hazen number is a measured value based on JIS K0071-1, the Gardner number is a measured value based on JIS K0071-2, and the number average molecular weight. Is a polystyrene equivalent value obtained by gel permeation chromatography (GPC) measurement. As the hydrocarbon resin (D), “Arcon” manufactured by Arakawa Chemical Industries, Ltd. and “Quinton” 1000 series manufactured by Zeon Corporation were used.

EVOH resin 75 parts, SEBS 19 parts, modified SEBS 3 parts, hydrocarbon-based resin 3 parts are dry blended, the resulting resin composition is melt-kneaded under the following conditions, extruded into a strand, cut with a pelletizer, An EVOH resin composition 1 having a cylindrical pellet was obtained.
Extruder: Diameter (D) 30 mm, twin screw extruder, L / D = 42
Screen pack: 90/90 mesh Screw rotation speed: 160 rpm
Set temperature: C1 / C2 / C3 / C4 / C5 / C6-D = 150/200/220/220/220/220
-℃

(EVOH resin composition 2)
As the EVOH resin (A), EVOH (Soeneol “AT4406EB” manufactured by Nippon Synthetic Chemical Co., Ltd. with ethylene content 29 mol%, saponification degree = 99.6 mol%, MFR = 6 g / 10 min (210 ° C., 2160 g)) is used. It was.

  As the inorganic fine particles (E), plate-shaped hydrous magnesium silicate (silicon dioxide-magnesium oxide main component, average particle size 1.4 μm, manufactured by Hayashi Kasei Co., Ltd., “Micellton”) was used.

EVOH resin 96.7 parts, plate-like hydrous magnesium silicate 2.3 parts, and ethylene bis stearamide (“Alfro H50FP” manufactured by Nippon Oil & Fats Co., Ltd.) 1.0 parts as a lubricant are dry blended to obtain a resin composition obtained Was melt-kneaded under the following conditions, extruded into a strand, and cut with a pelletizer to obtain EVOH resin composition 2 in a cylindrical pellet.
Extruder: Diameter (D) 30 mm, twin screw extruder, L / D = 42
Screen pack: 90/90 mesh Screw rotation speed: 130rpm
Setting temperature: C1 / C2 / C3 / C4 / C5 / C6-D = 180/200/210/210/210 / 210- ° C.

  90 parts of EVOH resin composition 1 and 10 parts of EVOH resin composition 2 were dry blended to obtain a resin composition.

The obtained resin composition was formed into a film (thickness 30 μm) under the following conditions.
Extruder: Diameter (D) 40 mm, L / D = 28
Screw: Full flight type, Compression ratio: 3.5
Screen pack: 90/120/90 mesh Die: 450 mm wide, coat hanger type Setting temperature: C1 / C2 / C3 / C4 / A / D = 180/200/220/220/220/220 ° C.
Screw rotation speed: 10 rpm
Take-up speed: 3 m / min
Roll temperature: 80 ℃

  About the film obtained from the resin composition, blocking resistance and bending resistance were evaluated based on the following evaluation method.

[Measurement evaluation method]
(1) Blocking resistance A single-layer film having a thickness of 30 μm produced from the adjusted resin composition was subjected to a coefficient of friction according to JIS K7312 using an autograph manufactured by Shimadzu Corporation under the conditions of 20 ° C. and 50% RH. It was measured.

(2) Bending resistance A single size film of A4 size and thickness of 30 μm in a dry state prepared with the adjusted resin composition was used at 23 ° C. and 50% RH using a gelbo flex tester manufactured by Rigaku Corporation. A torsion test was conducted. The conditions of the gelboflex tester are twist: 440 °, 3.5 inches, and horizontal direction: 2.5 inches.
After the twist test was applied 500 times (40 cycles / min), the number of pinholes generated per 28 cm × 17 cm in the center of the single-layer film was counted. This test was tried five times, and the occurrence state (number of occurrences) of pinholes was visually observed and evaluated as follows.
○ ――― The average number of occurrences is 0 to less than 5 × ――― The average value of occurrences is 5 or more

Example 2 A resin composition was prepared and evaluated in the same manner as in Example 1 except that 80 parts of EVOH resin composition 1 and 20 parts of EVOH resin composition 2 were used in Example 1.

Comparative Example 1 A resin composition was prepared in the same manner as in Example 1 except that the EVOH resin composition 1 was changed to 100 parts in Example 1, and was similarly evaluated.

The evaluation results of Examples and Comparative Examples are summarized in Table 1.

  The resin composition obtained in Example 1 maintained excellent bending resistance as in Comparative Example 1. Moreover, it turns out that it is excellent in blocking resistance rather than the comparative example 1.

  Example 2 was obtained by increasing the proportion of the inorganic fine particle (E) component with respect to Example 1, but such a resin composition maintained the same excellent bending resistance as Example 1. . Moreover, it turns out that it is further excellent in blocking resistance than Example 1.

  Comparative Example 1 is a comparative example in which inorganic fine particles (E) were not blended. In the case where the inorganic fine particles (E) do not coexist, the melt resistance of the melt-formed film was greatly deteriorated.

Since the molded product obtained from the resin composition of the present invention is excellent in flexibility and blocking resistance, it is very useful as a liquid packaging material for a wide range of applications.

Claims (7)

Saponified ethylene-vinyl ester copolymer (A) having an ethylene content of 20 to 60 mol%, a styrenic thermoplastic elastomer (B) containing no polar group, a styrenic thermoplastic elastomer (C) containing a polar group, A resin composition comprising a hydrocarbon-based resin (D) having a number average molecular weight of 100 to 3000 and a softening point of 60 ° C. or higher and lower than 170 ° C., and inorganic fine particles (E). Saponified ethylene-vinyl ester copolymer having an ethylene content of 20 to 60 mol%, based on the total amount of the styrenic thermoplastic elastomer (B) containing no polar group and the styrenic thermoplastic elastomer (C) containing the polar group 2. The resin composition according to claim 1, wherein the content ratio (A) / [(B) + (C)] of (A) is greater than 50/50 and 99/1 or less (weight). The content ratio (C) / (B) of the styrenic thermoplastic elastomer (C) containing a polar group to the styrenic thermoplastic elastomer (B) containing no polar group is 0.01 to 10 (weight). The resin composition according to claim 1 or 2. Saponified ethylene-vinyl ester copolymer (A) having an ethylene content of 20 to 60 mol%, a styrenic thermoplastic elastomer (B) containing no polar group, a styrenic thermoplastic elastomer (C) containing a polar group, And the number average molecular weight is 100 to 3000, the number average molecular weight is 100 to 3000, and the softening point is 60 ° C. or more with respect to the total amount of the hydrocarbon-based resin (D) whose softening point is 60 ° C. or more and less than 170 ° C. The resin composition according to any one of claims 1 to 3, wherein the content of the hydrocarbon-based resin (D) that is lower than 170 ° C is 0.5 to 7.5% by weight. Saponified ethylene-vinyl ester copolymer (A) having an ethylene content of 20 to 60 mol%, a styrenic thermoplastic elastomer (B) containing no polar group, a styrenic thermoplastic elastomer (C) containing a polar group, And the content of the inorganic fine particles (E) with respect to the total amount of the hydrocarbon resin (D) and the inorganic fine particles (E) having a number average molecular weight of 100 to 3000 and a softening point of 60 ° C. or higher and lower than 170 ° C. It is 0.001 to 5 weight%, The resin composition in any one of Claims 1-4. The multilayer structure which has at least one layer containing the resin composition in any one of Claims 1-5. A molded article containing the resin composition according to claim 1.