JP5575481B2 - Retort packaging material and method for producing the same - Google Patents

Description

  The present invention relates to a molded article excellent in oxygen absorption, hot water resistance, heat resistance, impact resistance, flexibility and gas barrier properties. In particular, the present invention relates to a molded article made of a resin composition containing a thermoplastic resin having a carbon-carbon double bond and a modified ethylene-vinyl alcohol copolymer. Moreover, it is related with the method of manufacturing such a molded article.

  The ethylene-vinyl alcohol copolymer (hereinafter sometimes abbreviated as EVOH) has a very low gas permeation amount of various gases such as oxygen compared to other plastics, and has excellent gas barrier properties and good melt moldability. For this reason, it is widely used as a packaging material for stably storing contents such as foods and cosmetics whose quality changes with oxygen or the like for a long period of time. Recently, EVOH is also used for applications other than food containers such as fuel tanks, fuel pipes, and agricultural chemical containers because of its excellent chemical resistance and low permeability of various organic solvents. However, if the packaging material using EVOH is used for retort sterilization (usually 80 to 145 ° C., normal pressure to 0.2 MPa, in the presence of moisture), EVOH will be whitened and deformed, or the gas barrier properties will be reduced. There was a case.

  In order to improve the hot water resistance required for such retort sterilization, various methods have been proposed in the past for techniques for crosslinking EVOH. For example, Patent Document 1 describes that a compound having an epoxy group and an allyl group is blended in EVOH and then crosslinked by light or heat. Small and hardly cross-linked. This is presumably because the epoxy group hardly reacts with EVOH. Moreover, when manufacturing the said compound, since it is necessary to mix | blend a compound which has an epoxy group and an allyl group in large quantities, these compounds remain | survive and become a sanitary problem especially when using it for a food packaging container. There is concern.

  In Patent Document 2 and Patent Document 3, EVOH is added with at least one crosslinking agent and crosslinking aid selected from a polyfunctional allyl compound, a polyfunctional (meth) acrylic compound, a polyhydric alcohol, and a metal oxide. Although there is a description of irradiating a wire to crosslink, there is also a concern about sanitary problems due to residual additives. In addition, the cross-linking agent gelled by reacting with EVOH at the stage of melt kneading, and there was a problem in industrial long-term operation during resin production.

  Patent Document 4 describes that EVOH is added with a compound having two or more allyl ether groups, and is irradiated with an electron beam to crosslink, but this also has a sanitary problem because the additive remains. Conceivable.

  Patent Document 5 describes a method in which triallyl cyanurate and triallyl isocyanurate are used as a crosslinking agent, and these are melt-kneaded with EVOH and then irradiated with an electron beam to crosslink EVOH. When triallyl isocyanurate remains, particularly when used in food packaging containers, there are concerns about hygiene problems. Further, triallyl cyanurate and triallyl isocyanurate gelled by reacting with EVOH at the stage of melt kneading, and there was a problem in long-term operation.

  Patent Document 6 describes a method in which an EVOH film is brought into contact with water to be in a water-containing state and is crosslinked by irradiation with an electron beam. However, in this method, there is a problem that it is necessary to immerse the film in water for a long time, and high-speed production is difficult.

  Patent Document 7 describes that flexibility is improved while keeping gas barrier properties as much as possible by modifying EVOH with a specific epoxy compound. However, there is a problem that the melting point is greatly lowered by modification, and further improvement is necessary for use in applications requiring heat resistance. Patent Document 8 describes a resin composition comprising modified EVOH described in Patent Document 7 and unmodified EVOH.

  In addition, the gas barrier property of EVOH is never zero, and permeates a non-negligible amount of gas. In particular, EVOH is known to have reduced gas barrier properties under conditions such as during retort sterilization and immediately after treatment. In order to reduce such gas permeation, in particular oxygen permeation, which has a great influence on the contents of the package, in particular the quality of the food, and oxygen already present in the package at the time of packaging of the contents In order to absorb and remove oxygen, it is known to use an oxygen absorbent mixed with the packaging material.

  For example, as a compound suitable for oxygen absorption, a composition containing an ethylenically unsaturated hydrocarbon and a transition metal catalyst (see Patent Document 9) has been proposed. Moreover, the resin composition containing EVOH and an oxygen absorber is proposed (refer patent document 10, patent document 11, and patent document 12). In particular, since a resin composition containing EVOH can be melt-molded in the same manner as EVOH, it can be suitably used for various packaging materials.

  However, when a packaging material or a resin composition in which the above oxygen absorbent is mixed is used as a packaging material, the oxygen absorbent is decomposed as oxygen absorption proceeds, and an unpleasant odor may be generated. Therefore, there is still room for improvement in applications where odorlessness is required. As a result of repeated research to solve the above-mentioned problems, some of the inventors have obtained thermoplastic resins and transition metal salts that do not generate an unpleasant odor and have a carbon-carbon double bond substantially only in the main chain. It came to the invention of the oxygen-absorbing resin composition to contain (refer patent document 13). By using a packaging material containing EVOH containing such an oxygen-absorbing resin composition as a constituent component, oxygen entering the packaging material can be reduced even under conditions such as during retort sterilization and immediately after the treatment. It becomes possible.

  As described so far, it is known that by introducing a crosslink into EVOH, it is possible to prevent deterioration in performance and quality such as whitening, deformation, and deterioration of barrier properties of EVOH during retort sterilization treatment. On the other hand, barrier performance can be improved by mixing an oxygen absorbent into EVOH. However, these Patent Documents 1 to 13 use EVOH in combination with a crosslinking technique and an oxygen absorbent technique to prevent EVOH from being deformed or whitened during retort sterilization, and long in retort sterilization and subsequent storage. There is no idea of reducing the oxygen that enters the packaging material over time. Furthermore, in patent documents 1-5, when using for a food packaging container, there also exists a problem on hygiene. Therefore, there has been a demand for a technique that improves the hot water resistance of EVOH having a good gas barrier property, further improves the oxygen barrier property, and does not cause sanitary problems.

  On the other hand, in the field of food packaging containers, for retort packaging materials, breaking of packaging materials during filling of contents, retort sterilization processing, transportation, etc. is often a problem, which is excellent for packaging materials. Impact resistance and flexibility are required. That is, in addition to the above-mentioned performances such as hot water resistance and oxygen barrier properties, a material excellent in impact resistance and flexibility is desired. However, in the above prior art, when the EVOH film is subjected to a crosslinking treatment, its flexibility is generally lowered as compared with that before the crosslinking treatment. Moreover, in the resin composition which mixed the oxygen absorber, there is no description about the impact resistance.

JP 63-8448 A JP-A-5-271498 JP-A-9-157421 JP-A-9-234833 Japanese Patent Laid-Open No. 62-252409 JP 56-49734 A WO02 / 092643 WO03 / 072653 Japanese Patent Laid-Open No. 5-115776 JP 2001-106866 A JP 2001-106920 A JP 2002-146217 A Japanese Patent Laying-Open No. 2005-187808

  The present invention has been made to solve the above-mentioned problems, contains almost no harmful cross-linking agent, is excellent in hot water resistance, heat resistance, impact resistance and flexibility, and has oxygen absorption. It aims at providing the molded article excellent in gas barrier property. Moreover, it aims at providing the suitable manufacturing method for manufacturing such a molded article.

The above-mentioned problems include a thermoplastic resin (G) having a carbon-carbon double bond (hereinafter referred to as a thermoplastic resin (G)) and a modified ethylene-vinyl alcohol copolymer (C) (hereinafter referred to as a modified EVOH (C )) And a retort packaging material comprising a multilayer structure comprising a layer comprising a resin composition, wherein the modified EVOH (C) comprises an unmodified ethylene-vinyl alcohol copolymer (A) ( Hereinafter, it is obtained by modifying an unmodified EVOH (A)) with an epoxy compound (B) having a double bond (hereinafter referred to as an epoxy compound (B)). The amount of modification by the epoxy compound (B) is 0.1 to 10 mol% with respect to the monomer unit of the unmodified EVOH (A), and at least a part of the resin composition is crosslinked. retort It is solved by providing a packaging material.

  The thermoplastic resin (G) preferably has a carbon-carbon double bond substantially only in the main chain, and is particularly preferably polyoctenylene. In the present specification, “polyoctenylene” means a polymer obtained by ring-opening metathesis polymerization of cyclooctene in the presence of a metathesis polymerization catalyst, as will be described later.

  In a preferred embodiment, the epoxy compound (B) is allyl glycidyl ether. It is also a preferred embodiment that the resin composition further contains an unmodified ethylene-vinyl alcohol copolymer (D) (hereinafter referred to as unmodified EVOH (D)). It is preferable that the resin composition further contains a transition metal salt (H), preferably a cobalt salt. The resin composition may further contain a compatibilizer (I).

A preferred embodiment of the packaging material for retort of the present invention is a film or a sheet. Furthermore, retort lid and pouch are also preferred embodiments.

Furthermore, the above-described problems are a process of producing a resin composition by mixing a thermoplastic resin (G) and a modified ethylene-vinyl alcohol copolymer (C), a process of molding the resin composition, and a molded article. The problem is solved by providing a method for producing a packaging material for retort having a step of crosslinking at least a part of the resin composition .

In the method for producing a packaging material for retort according to the present invention, when the resin composition is produced, it is preferable to further mix unmodified EVOH (D). Further, a transition metal salt (H) or a compatibilizer (I) may be further mixed.

In the above manufacturing method, an electron beam, X-rays, gamma rays, or irradiated with at least one member selected from the group consisting of ultraviolet and visible light, to crosslink at least a portion of the resin composition is molded by heating This is a preferred embodiment.

  The molded product containing the thermoplastic resin (G) and the modified EVOH (C) of the present invention has excellent oxygen absorbability and hardly contains harmful crosslinking agents, and has hot water resistance, heat resistance, Excellent impact, flexibility and gas barrier properties. Therefore, it is suitable as a packaging container for products such as foods and cosmetics that are easily deteriorated by oxygen, and as a molded product requiring hot water resistance and heat resistance.

  The modified EVOH (C) used in the present invention is obtained by reacting an epoxy compound (B) with a hydroxyl group of unmodified EVOH (A).

  The ethylene content of the unmodified EVOH (A) used in the present invention is preferably 5 to 55 mol%, more preferably 20 to 55 mol%, still more preferably 25 to 50 mol%. When the ethylene content is less than 5 mol%, the water resistance is poor, and when it is greater than 60 mol%, the gas barrier property is inferior. The ethylene content of the resulting modified EVOH (C) is the same as the ethylene content of the raw EVOH (A) that is the raw material.

  The saponification degree of the unmodified EVOH (A) is preferably 90 mol% or more, preferably 98 mol% or more, and more preferably 99 mol% or more. When the saponification degree is less than 90 mol%, the gas barrier property and the thermal stability are inferior.

  Further, as will be described later, the modified EVOH (C) is preferably obtained by allowing the reaction between the unmodified EVOH (A) and the epoxy compound (B) in an extruder. EVOH (A) is exposed to heating conditions. At this time, if the unmodified EVOH (A) contains an excessive amount of alkali metal salt and / or alkaline earth metal salt, the resulting modified EVOH (C) may be colored. Moreover, problems, such as a viscosity fall of modified EVOH (C), arise and there exists a possibility that a moldability may fall. Moreover, when using a catalyst like the after-mentioned, in order to deactivate a catalyst, it is preferable that those addition amounts are as small as possible.

  In order to avoid the above problem, the alkali metal salt contained in the unmodified EVOH (A) is preferably 50 ppm or less in terms of metal element. In a more preferred embodiment, the alkali metal salt contained in the unmodified EVOH (A) is 30 ppm or less, more preferably 20 ppm or less in terms of metal element. Further, from the same viewpoint, the alkaline earth metal salt contained in the unmodified EVOH (A) is preferably 20 ppm or less, more preferably 10 ppm or less in terms of metal element, and 5 ppm or less. Is more preferable, and most preferably, the alkaline earth metal salt is not substantially contained in the unmodified EVOH (A).

  The suitable melt flow rate (MFR) (under 190 ° C. and 2160 g load) of the unmodified EVOH (A) used in the present invention is 0.1 to 100 g / 10 minutes, preferably 0.3 to 30 g / 10. Min, more preferably 0.5 to 20 g / 10 min. However, those having a melting point near 190 ° C. or exceeding 190 ° C. were measured under a load of 2160 g and at a plurality of temperatures higher than the melting point. The value is extrapolated to 190 ° C. Two or more kinds of unmodified EVOH (A) having different MFRs can also be mixed and used.

  The epoxy compound (B) used in the present invention preferably has one epoxy group and one or more double bonds in the molecule. That is, it is preferably a monovalent epoxy compound. The molecular weight is preferably 500 or less. Those having a plurality of epoxy groups have a problem of crosslinking during modification. The type of double bond is particularly preferably a vinyl group which is a monosubstituted olefin, and next preferably a vinylene group or a vinylidene group which is a disubstituted olefin. Next preferred are trisubstituted olefins. Tetrasubstituted olefins are not suitable for the purposes of the present invention due to poor reactivity.

  Moreover, what can remove easily the thing added excessively from modified | denatured EVOH (C) as an epoxy compound (B) is preferable. As the removal method, it is practical to volatilize and remove from the vent of the extruder. Therefore, the boiling point is preferably 250 ° C. or less, and more preferably 200 ° C. or less. Moreover, it is preferable that carbon number of an epoxy compound (B) is 4-10. Specific examples of such an epoxy compound having a double bond include 1,2-epoxy-3-butene, 1,2-epoxy-4-pentene, 1,2-epoxy-5-hexene, 1,2- Examples include epoxy-4-vinylcyclohexane, allyl glycidyl ether, methallyl glycidyl ether, and ethylene glycol allyl glycidyl ether, and particularly preferably allyl glycidyl ether. Moreover, it is also possible to wash and remove from the vent of an extruder, and it is also preferable in this case that an epoxy compound (B) is soluble in water.

  The reaction conditions of the epoxy compound (B) and the unmodified EVOH (A) are not particularly limited, but in the same manner as described in WO02 / 092643 (Patent Document 7), the unmodified EVOH (A ) Is preferably reacted with an epoxy compound (B) having a double bond. At this time, it is preferable to add a catalyst, and in that case, it is preferable to add a carboxylate as a deactivator after the reaction. It is preferable to add the epoxy compound (B) to the unmodified EVOH (A) in a molten state in the extruder because it can prevent volatilization of the epoxy compound (B) and easily control the reaction amount. The epoxy compound (B) having an excessively added double bond can be removed from the vent of the extruder. Furthermore, by washing the obtained pellets with warm water, the remaining epoxy compound (B) can be removed and at the same time, the remaining catalyst can be removed.

  It is preferable that the catalyst to be used contains a metal ion belonging to Groups 3-12 of the periodic table. The most important thing as a metal ion used for a catalyst is having moderate Lewis acidity. From this point, ions of metals belonging to Groups 3 to 12 of the periodic table are used. Among these, ions of metals belonging to Group 3 or Group 12 of the periodic table are preferable because they have appropriate Lewis acidity, and ions of zinc, yttrium, and gadolinium are more preferable. Among them, a catalyst containing zinc ions is optimal because it has an extremely high catalytic activity and the thermal stability of the resulting modified EVOH (C) is excellent.

  The addition amount of metal ions belonging to Groups 3 to 12 of the periodic table is preferably 0.1 to 20 μmol / g in terms of the number of moles of metal ions relative to the mass of unmodified EVOH (A). When it is too much, unmodified EVOH (A) may be gelled during melt-kneading, and is more preferably 10 μmol / g or less. On the other hand, if the amount is too small, the effect of adding the catalyst may not be sufficiently achieved, and the amount is more preferably 0.5 μmol / g or more. In addition, since the suitable addition amount of the ion of the metal which belongs to periodic table group 3-12 changes also with the kind of metal to be used and the kind of below-mentioned anion, it adjusts suitably also considering those points. Is done.

  The anion species of the catalyst containing a metal ion belonging to Groups 3 to 12 of the periodic table is not particularly limited, but it is preferable that the conjugate acid contains a monovalent anion which is a strong acid equal to or higher than sulfuric acid. This is because an anion in which the conjugate acid is a strong acid usually has a low nucleophilicity, so that it is difficult to react with the epoxy compound, and anion species are consumed by the nucleophilic reaction to prevent loss of catalytic activity. Further, by having such an anion as a counter ion, the Lewis acidity of the catalyst is improved and the catalytic activity is improved.

Monovalent anions in which the conjugate acid is a strong acid equivalent to or higher than sulfuric acid include sulfonate ions such as methanesulfonate ion, ethanesulfonate ion, trifluoromethanesulfonate ion, benzenesulfonate ion, and toluenesulfonate ion; chlorine Halogen ions such as ions, bromine ions and iodine ions; perchlorate ions; tetrafluoroborate ions (BF ₄ ⁻ ), hexafluorophosphate ions (PF ₆ ⁻ ), hexafluoroarsinate ions (AsF ₆ ⁻ ), hexafluoro Anions having four or more fluorine atoms such as antimonate ions; tetraphenylborate derivative ions such as tetrakis (pentafluorophenyl) borate ions; tetrakis (3,5-bis (trifluoromethyl) phenyl) borate; And carborane derivative ions such as cobalt (III) ions and bis (undecahydride-7,8-dicarboundecaborate) iron (III) ions. The Of these, sulfonic acid ions are preferable, and trifluoromethanesulfonic acid ions are most suitable.

  As described above, the catalyst used preferably contains a monovalent anion whose conjugate acid is a strong acid equal to or higher than sulfuric acid, but all the anion species in the catalyst must be the same anion species. There is no. Rather, it is preferable that the conjugate acid simultaneously contains an anion which is a weak acid.

  Examples of anions in which the conjugate acid is a weak acid include alkyl anions, aryl anions, alkoxides, aryloxy anions, carboxylates, and acetylacetonates and derivatives thereof. Of these, alkoxide, carboxylate, acetylacetonate and derivatives thereof are preferably used.

  It is preferable that the number of moles of an anion in which the conjugate acid is a strong acid equal to or higher than that of sulfuric acid is 0.2 to 1.5 times the number of moles of metal ions in the catalyst. When the molar ratio is less than 0.2 times, the catalytic activity may be insufficient, more preferably 0.3 times or more, and even more preferably 0.4 times or more. On the other hand, when the molar ratio exceeds 1.5 times, the modified EVOH (C) may be gelled, and is more preferably 1.2 times or less. The molar ratio is optimally 1 time. In addition, when the raw material unmodified EVOH (A) contains an alkali metal salt such as sodium acetate, the amount of the anion whose conjugate acid is a strong acid equal to or higher than that of sulfuric acid is consumed as much as it is neutralized. You can increase the number.

  The method for preparing the catalyst is not particularly limited. As a preferred method, a metal compound belonging to Groups 3 to 12 of the periodic table is dissolved or dispersed in a solvent, and the resulting solution or suspension is mixed with a conjugate acid in sulfuric acid. And a method of adding a strong acid such as sulfonic acid equivalent to or more than the above. Examples of the metal compound belonging to Groups 3 to 12 of the periodic table used as a raw material include alkyl metals, aryl metals, metal alkoxides, metal aryloxides, metal carboxylates, and metal acetylacetonates. Here, when adding a strong acid to the solution or suspension of such a metal compound, it is preferable to add little by little. The solution containing the catalyst thus obtained can be introduced directly into the extruder.

  The solvent for dissolving or dispersing the metal compound is preferably an organic solvent, particularly an ether solvent. This is because it hardly reacts even at the temperature in the extruder and the solubility of the metal compound is good. Examples of ether solvents include dimethyl ether, diethyl ether, tetrahydrofuran, dioxane, 1,2-dimethoxyethane, diethoxyethane, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and the like. As the solvent to be used, a solvent that is excellent in solubility of the metal compound, has a relatively low boiling point, and can be almost completely removed by the vent of the extruder is preferable. In that respect, diethylene glycol dimethyl ether, 1,2-dimethoxyethane and tetrahydrofuran are particularly preferred.

  In the above-described catalyst preparation method, instead of the strong acid to be added, an ester of a strong acid such as a sulfonic acid ester may be used. Since esters of strong acids are usually less reactive than strong acids themselves, they may not react with metal compounds at room temperature, but they are active in an extruder when placed in a high-temperature extruder maintained at around 200 ° C. A catalyst can be produced.

  As a method for preparing the catalyst, another method described below can be adopted. First, an aqueous catalyst solution is prepared by mixing the water-soluble metal compound and a strong acid such as a sulfonic acid having a conjugate acid equivalent to or higher than sulfuric acid in an aqueous solution. At this time, the aqueous solution may contain an appropriate amount of alcohol. The obtained catalyst aqueous solution is brought into contact with unmodified EVOH (A), and then dried to obtain unmodified EVOH (A) containing the catalyst. Specifically, a method of immersing unmodified EVOH (A) pellets, particularly porous hydrous pellets, in the catalyst aqueous solution is preferable. In this case, the dry pellets thus obtained can be introduced into an extruder.

  The catalyst deactivator used is not particularly limited as long as it reduces the function of the catalyst as a Lewis acid. Alkali metal salts are preferably used. In order to deactivate a catalyst containing a monovalent anion whose conjugate acid is a strong acid equal to or higher than sulfuric acid, it is necessary to use an alkali metal salt of an anion of an acid weaker than the conjugate acid of the anion. By doing so, the counter ion of the metal ion belonging to Groups 3 to 12 of the periodic table constituting the catalyst is exchanged with a weak acid anion, and as a result, the Lewis acidity of the catalyst is lowered. The cation species of the alkali metal salt used for the catalyst deactivator is not particularly limited, and sodium salt, potassium salt and lithium salt are preferred as examples. Also, the anionic species is not particularly limited, and carboxylates, phosphates and phosphonates are exemplified as suitable ones.

  The use of a salt such as sodium acetate or dipotassium monohydrogen phosphate as the catalyst deactivator can significantly improve the thermal stability, but it may still be insufficient depending on the application. This is because metal ions belonging to Groups 3 to 12 of the Periodic Table still have some activity as a Lewis acid and thus act as a catalyst for the decomposition and gelation of the modified EVOH (C). it is conceivable that. As a method for further improving this point, it is preferable to add a chelating agent that strongly coordinates to ions of metals belonging to Groups 3 to 12 of the periodic table. As a result of such a chelating agent being able to strongly coordinate to the ions of the metal, the Lewis acidity can be almost completely lost, and a modified EVOH (C) excellent in thermal stability can be provided. Moreover, the strong acid which is the conjugate acid of the anion contained in a catalyst can also be neutralized as mentioned above by the said chelating agent being an alkali metal salt.

  Suitable chelating agents used as catalyst deactivators include oxycarboxylates, aminocarboxylates, aminophosphonates and the like. Specifically, examples of the oxycarboxylate include disodium citrate, disodium tartrate, and disodium malate. Aminocarboxylates include nitrilotriacetic acid trisodium, ethylenediaminetetraacetic acid disodium, ethylenediaminetetraacetic acid trisodium, ethylenediaminetetraacetic acid tripotassium, diethylenetriaminepentaacetic acid trisodium, 1,2-cyclohexanediamine tetraacetic acid trisodium, ethylenediamine diacetate. Illustrative examples include monosodium acetate and monosodium N- (hydroxyethyl) iminodiacetic acid. Examples of aminophosphonates include nitrilotrismethylenephosphonic acid hexasodium, ethylenediaminetetra (methylenephosphonic acid) octasodium, and the like. Of these, polyaminopolycarboxylic acid is preferred, and an alkali metal salt of ethylenediaminetetraacetic acid is most preferred in terms of performance and cost.

  The addition amount of the catalyst deactivator is not particularly limited, and is appropriately adjusted according to the type of metal ion contained in the catalyst, the number of coordination sites of the chelating agent, etc., but the catalyst relative to the number of moles of metal ions contained in the catalyst It is preferable that the molar ratio of the deactivator is 0.2 to 10. If the ratio is less than 0.2, the catalyst may not be sufficiently deactivated, more preferably 0.5 or more, and even more preferably 1 or more. On the other hand, when the ratio exceeds 10, the resulting modified EVOH (C) may be colored, and the production cost may increase, more preferably 5 or less, and even more preferably 3 or less. It is.

  The method for introducing the catalyst deactivator into the extruder is not particularly limited. However, in order to uniformly disperse the catalyst deactivator, it is preferably introduced as a solution of the catalyst deactivator with respect to the molten modified EVOH (C). In consideration of the solubility of the catalyst deactivator and the influence on the surrounding environment, it is preferably added as an aqueous solution.

  The catalyst deactivator may be added to the extruder after melt-kneading unmodified EVOH (A) and epoxy compound (B) in the presence of the catalyst. However, it is preferable to add the catalyst deactivator after melt-kneading unmodified EVOH (A) and the epoxy compound (B) in the presence of a catalyst to remove the unreacted epoxy compound (B). As described above, when the catalyst deactivator is added as an aqueous solution, the catalyst deactivator is added before removing the unreacted epoxy compound (B). This is because water mixes in the epoxy compound (B), and the separation operation takes time. In addition, it is also preferable to remove moisture by a vent or the like after adding the aqueous solution of the catalyst deactivator.

  In the production method of modified EVOH (C), when a catalyst deactivator is used, a suitable production process includes (1) a melting step of unmodified EVOH (A); (2) epoxy compound (B) and catalyst (3) Step of removing unreacted epoxy compound (B); (4) Step of adding catalyst deactivator aqueous solution; (5) Step of removing moisture under reduced pressure Is done.

  From the viewpoint of carrying out the reaction smoothly, it is preferable to remove moisture and oxygen from the system. For this reason, you may remove a water | moisture content and oxygen using a vent etc. before adding an epoxy compound (B) in an extruder.

  The modification amount of the modified EVOH (C) by the epoxy compound (B) is in the range of 0.1 to 10 mol% with respect to the monomer unit of the unmodified EVOH (A), more preferably from 0.3 to It is in the range of 5 mol%, more preferably in the range of 0.5 to 3 mol%. When the amount of modification is 0.1 mol% or less, the effect of modification is small, and when it exceeds 10 mol%, there is a drawback that gas barrier properties and thermal stability are lowered.

  When the epoxy compound (B) having a double bond is reacted with unmodified EVOH (A), an epoxy compound (E) having no double bond may be added. Thereby, the crystallinity can be lowered while minimizing the degradation of the gas barrier property of EVOH, and the performance such as stretchability, thermoformability and flexibility can be improved. Specific examples of such an epoxy compound (E) having no double bond are described in WO 02/092643 (Patent Document 7). Among these, from the viewpoint of performance, epoxy ethane (ethylene oxide), 1, Monovalent epoxy compounds having a molecular weight of 500 or less, such as 2-epoxypropane (propylene oxide), 1,2-epoxybutane, and glycidol are preferable. It is preferable that carbon number of the epoxy compound (E) which does not have a double bond is 2-8.

  The method for adding the epoxy compound (E) having no double bond is not particularly limited. However, from the viewpoint of production efficiency, it is preferable to modify the unmodified EVOH (A), the epoxy compound (B) having a double bond, and the epoxy compound (E) having no double bond simultaneously. Specifically, a method of adding a mixture of an epoxy compound (B) having a double bond and an epoxy compound (E) having no double bond is exemplified as a suitable method. At this time, it is more preferable to add the catalyst at the same time.

  The amount of modification by the epoxy compound (E) having no double bond is preferably in the range of 0.1 mol% or more and 30 mol% or less with respect to the monomer unit of the unmodified EVOH (A). . The amount of modification by the epoxy compound (E) having no double bond is more preferably 20 mol% or less, and further preferably 15 mol% or less. When the amount of modification by the epoxy compound (E) having no double bond is increased, there is a problem that the gas barrier property is greatly lowered. From the viewpoint of improving effects such as stretchability, thermoformability, and flexibility, the amount of modification by the epoxy compound (E) having no double bond is more preferably 0.5 mol% or more, and still more preferably. Is 1 mol% or more.

  The preferred melt flow rate (MFR) of the modified EVOH (C) (190 ° C. under 2160 g load) is 0.1 to 100 g / 10 min, preferably 0.3 to 30 g / 10 min, more preferably 0.5 to 20 g / 10 min. However, those having a melting point near 190 ° C. or exceeding 190 ° C. were measured under a load of 2160 g and at a plurality of temperatures higher than the melting point. The value is extrapolated to 190 ° C.

  The molded article of the present invention contains a thermoplastic resin (G). Here, it is preferable that the thermoplastic resin (G) has a carbon-carbon double bond substantially only in the main chain. Here, the thermoplastic resin (G) “has a carbon-carbon double bond substantially only in the main chain” means that the carbon-carbon double bond existing in the main chain of the thermoplastic resin (G) is It is 90% or more of all carbon-carbon double bonds in the molecule, and the carbon-carbon double bond existing in the side chain is 10% or less of all carbon-carbon double bonds in the molecule. The carbon-carbon double bond present in the main chain is preferably 93% or more, more preferably 95% or more, and the carbon-carbon double bond present in the side chain is preferably 7% or less, More preferably, it is 5% or less.

  Since this thermoplastic resin (G) has a carbon-carbon double bond in its molecule, it can react with oxygen efficiently, and as a result, an oxygen absorbing function is obtained. In the present specification, the “carbon-carbon double bond” does not include a carbon-carbon double bond in an aromatic ring. The amount of the carbon-carbon double bond of the thermoplastic resin (G) is preferably 0.001 mol / g to 0.020 mol / g, more preferably 0.005 mol / g to 0.018 mol / g, Preferably it is 0.007 mol / g-0.012 mol / g. When the carbon-carbon double bond content is less than 0.001 mol / g, the resulting molded article tends to have an insufficient oxygen absorption function. When the content is 0.020 mol / g or more, this thermoplasticity When the resin (G) is molded together with other resins, coloring and shading tend to occur.

Examples of the thermoplastic resin (G) include polyoctenylene, polyheptenylene, polynorbornene, polycyclopentadiene, isoprene dimer hydrogenated ring-opened polymer, and the like. The isoprene dimer hydrogenated ring-opened polymer is represented by the following formula:
_{-CX = CX-CH 2 -CH 2} -CY 2 -CY 2 -CH 2 -CH 2 -
Here, one of the two X is a methyl group, the other is a hydrogen atom, and one of the four Y is a methyl group, and the remaining three are hydrogen atoms.

  The thermoplastic resin (G) may contain various hydrophilic groups. Here, the hydrophilic group is a hydroxyl group, an alkoxy group having 1 to 10 carbon atoms, an amino group, an aldehyde group, a carboxyl group, an epoxy group, an ester group, a carboxylic anhydride group, or a boron-containing polar group (for example, a boronic acid group). , Boronic acid ester group, boronic acid anhydride group, boronic acid base) and the like. These groups may exist in any part of the thermoplastic resin (G).

  The weight average molecular weight of the thermoplastic resin (G) is preferably 1,000 to 500,000, more preferably 10,000 to 250,000, and even more preferably 60,000 to 200,000. 000 range. When the weight average molecular weight of the thermoplastic resin (G) is less than 1,000 or more than 500,000, the moldability and handling properties of the resulting resin composition, strength and elongation when formed into a molded product The mechanical properties such as

  When using a thermoplastic resin (G) having a carbon-carbon double bond substantially only in the main chain, the carbon-carbon double bond and its allylic position are partially oxidized or cleaved by oxygen absorption. However, it is difficult to generate low molecular weight fragments as in the case where the carbon-carbon double bond in the side chain is cleaved, and it is difficult to generate odor substances.

  The thermoplastic resin (G) is preferably produced by a ring-opening metathesis polymerization of a cyclic olefin having 7 or more carbon atoms in an inert solvent in the presence of a polymerization catalyst and, if necessary, a chain transfer agent. Is done. This method has the advantage that there is no by-product of ethylene and the manufacturing process is not complicated.

  Examples of cyclic olefins having 7 or more carbon atoms include cyclomonoenes such as cycloheptene, cyclooctene, cyclononene, cyclodecene and norbornene; cyclodienes such as cyclooctadiene, cyclodecadiene, norbornadiene and dicyclopentadiene; and cyclododecatriene. And cyclotrienes. These may have a substituent such as an alkoxy group, a carbonyl group, an alkoxycarbonyl group, or a halogen atom. Among these, cyclooctene is preferable in consideration of availability and economy.

  Examples of the polymerization catalyst (x) for ring-opening metathesis polymerization include a catalyst (x-1) mainly composed of a transition metal halide and a transition metal carbene complex catalyst (x-2). The catalyst (x-1) containing a transition metal halide as a main component is a catalyst containing a transition metal halide as a main component and an organometallic compound other than a transition metal as a promoter.

As the transition metal halide, halides of Group 4 to 8 transition metals in the periodic table are preferable. For example, molybdenum halides such as MoBr ₂ , MoBr ₃ , MoBr ₄ , MoCl ₄ , MoCl ₅ , MoF ₄ , MoOCl ₄ , and MoOF _4. Compound: tungsten halogen such as WBr ₂ , WCl ₂ , WBr ₄ , WCl ₄ , WCl ₅ , WCl ₆ , WF ₄ , WI ₂ , WOBr ₄ , WOCl ₄ , WOF ₄ , WCl ₄ (OC ₆ H ₄ Cl ₂ ) _{2 halides;} VOCl 3, vanadium halides such VOBr _3; such as TiCl 4, titanium halides such as TiBr ₄ and the like.

  Examples of organometallic compounds other than transition metals that function as the promoter include trimethylaluminum, triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, triphenylaluminum, tribenzylaluminum, diethylaluminum monochloride, -Organoaluminum compounds such as n-butylaluminum monochloride, diethylaluminum monoiodide, diethylaluminum monohydride, ethylaluminum sesquichloride, ethylaluminum dichloride, methylaluminoxane, isobutylaluminoxane; tetramethyltin, diethyldimethyltin, tetraethyltin, Dibutyldiethyltin, tetrabutyltin, tetraoctyltin, trioctyls Fluoride, trioctyltin chloride, trioctyltin bromide, trioctyltin iodide, dibutyltin difluoride, dibutyltin dichloride, dibutyltin dibromide, dibutyltin diiodide, butyltin trifluoride, butyltin trichloride, butyltin tribromide, dibutyltin tria Organotin compounds such as iodide; Organolithium compounds such as methyllithium, ethyllithium, n-butyllithium, sec-butyllithium and phenyllithium; Organic sodium compounds such as n-pentylsodium; Methylmagnesium iodide, ethylmagnesium bromide , Methylmagnesium bromide, n-propylmagnesium bromide, tert-butylmagnesium chloride, arylmagnesium chloride Organomagnesium compounds such as Lido; organozinc compounds such as diethylzinc; organocadmium compounds such as diethylcadmium; trimethylboron, triethylboron, tri-n-butylboron, triphenylboron, tris (perfluorophenyl) boron, N, And organic boron compounds such as N-dimethylanilinium tetrakis (perfluorophenyl) borate and trityltetrakis (perfluorophenyl) borate.

  The transition metal carbene complex catalyst (x-2) is a carbene complex compound of Group 4 to 8 transition metals of the periodic table, such as a tungsten carbene complex catalyst, a molybdenum carbene complex catalyst, a rhenium carbene complex catalyst, a ruthenium carbene complex catalyst, and the like. Can be mentioned. Among these, a ruthenium carbene complex catalyst is preferable. Specific examples of the ruthenium carbene complex catalyst include benzylidene (1,3-dimesitylimidazolidine-2-ylidene) (tricyclohexylphosphine) ruthenium dichloride, (1,3-dimesitylimidazolidine-2-ylidene) ( 3-methyl-2-buten-1-ylidene) (tricyclopentylphosphine) ruthenium dichloride, benzylidene (1,3-dimesityl-octahydrobenzimidazol-2-ylidene) (tricyclohexylphosphine) ruthenium dichloride, benzylidene [1,3 -Di (1-phenylethyl) -4-imidazoline-2-ylidene] (tricyclohexylphosphine) ruthenium dichloride, benzylidene (1,3-dimesityl-2,3-dihydrobenzimidazol-2-ylidene) (tricyclide) Hexylphosphine) ruthenium dichloride, benzylidene (tricyclohexylphosphine) (1,3,4-triphenyl-2,3,4,5-tetrahydro-1H-1,2,4-triazol-5-ylidene) ruthenium dichloride, ( Heteroatom-containing carbene such as 1,3-diisopropylhexahydropyrimidin-2-ylidene) (ethoxymethylene) (tricyclohexylphosphine) ruthenium dichloride, benzylidene (1,3-dimesitylimidazolidine-2-ylidene) pyridine ruthenium dichloride Examples thereof include, but are not limited to, a ruthenium carbene complex in which a compound and a neutral electron donating compound are bonded.

  These polymerization catalysts can be used alone or in admixture of two or more. Among these, it is preferable to use a transition metal carbene complex catalyst (x-2) because it does not require a cocatalyst and is highly active.

  The amount of the polymerization catalyst used in the ring-opening metathesis polymerization is a molar ratio of the catalyst to the cyclic olefin monomer used for the polymerization reaction, and the catalyst: cyclic olefin monomer = 1: 100 to 1: 2,000,000, preferably Is in the range of 1: 500 to 1: 1,000,000, more preferably 1: 1,000 to 1: 700,000. If the catalyst amount is too large, it is difficult to remove the catalyst after the reaction, and if it is too small, sufficient polymerization activity may not be obtained.

  Examples of the chain transfer agent include α-olefins such as 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 2-butene, 2-pentene, 2-hexene, 3-hexene, 2- Internal olefins such as heptene, 3-heptene, 2-octene, 3-octene and 4-octene can be preferably used. These may be used alone or in combination.

  The amount of the chain transfer agent used is not particularly limited as long as it is an amount capable of producing a polymer having a sufficient molecular weight in the polymerization reaction. For example, the molar ratio of the chain transfer agent to the cyclic olefin is in the range of cyclic olefin: chain transfer agent = 1,000: 1 to 20: 1, preferably 800: 1 to 50: 1.

  Examples of the inert solvent include saturated aliphatic hydrocarbons such as hexane, heptane, octane, nonane, decane, dodecane, cyclohexane, cycloheptane, and cyclooctane; aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene, and methylene chloride. , Halogenated hydrocarbons such as chloroform and carbon tetrachloride; ethers such as diethyl ether, tetrahydrofuran and 1,4-dioxane can be used. In view of easy solvent removal and operability, it is preferable to use saturated aliphatic hydrocarbons.

  Although the usage-amount of a solvent is not specifically limited, Usually, it is 1-1000 mass times with respect to the cyclic olefin to be used, Preferably it is 2-200 mass times, More preferably, it is the range of 3-100 mass times.

  The temperature at which the ring-opening metathesis polymerization is carried out depends on the type and amount of the solvent used and is not necessarily constant, but is usually in the range of −78 ° C. to 200 ° C., preferably in the range of 10 ° C. to 150 ° C. It is. The polymerization is preferably carried out in an inert gas atmosphere.

  An example of the production method when the thermoplastic resin (G) is polyoctenylene is as follows. Polyoctenylene can be synthesized by a method of performing ring-opening metathesis polymerization using cyclooctene as a raw material and using the above-described catalyst. Specifically, for example, ring-opening metathesis polymerization is carried out in the presence of the above-described solvent using a polymerization catalyst such as benzylidene (1,3-dimesitylimidazolidine-2-ylidene) (tricyclohexylphosphine) ruthenium dichloride. It is preferable to do this. The polymerization is performed within 72 hours, although it varies depending on the melting point and boiling point of the solvent used.

  In the production of the thermoplastic resin (G), in the thermoplastic resin (G) obtained by the ring-opening metathesis polymerization, an oligomer of about 10-mer form from a dimer of the cyclic olefin as a raw material is produced. It is difficult to suppress. From the viewpoint of odor, the content of oligomers having a molecular weight of 1,000 or less is preferably 6% by mass or less. It is therefore recommended to remove such oligomers. The method for removing the oligomer is not particularly limited. For example, after removing the catalyst and solvent after completion of the polymerization, a method of introducing an inert gas such as nitrogen under heating, a method of heating under high vacuum, a method of azeotropic removal with an azeotropic solvent such as water, etc. .

  Further, after the polymerization is completed, the catalyst and the solvent are removed, and the obtained thermoplastic resin (G) is processed into a strand, chip or pellet by a method such as extrusion molding, and then the thermoplastic resin (G) having a molecular weight exceeding 1,000. Oligomer can be removed by washing in contact with an organic solvent that does not substantially dissolve. Examples of such solvents include alcohols such as methanol, ethanol, propanol and isopropanol; ketones such as acetone and methyl ethyl ketone; esters such as methyl acetate and ethyl acetate; ethers such as diethyl ether and tert-butyl methyl ether. The amount of the solvent used is not particularly limited, and usually a range of 1 to 10,000 times by mass with respect to the thermoplastic resin (G) is preferable, and a range of 10 to 1,000 times by mass is more preferable. From the viewpoint of operability, the range of 20 to 800 mass times is more preferable. The temperature at which the solvent is washed is not particularly limited, and is usually in the range of −10 ° C. to 80 ° C., and the range of 0 ° C. to 60 ° C. is more preferable in consideration of operability. The washing method is not particularly limited, and a method of immersing the thermoplastic resin (G) processed into strands, chips or pellets in a solvent, or dispersing the thermoplastic resin (G) processed into strands, chips or pellets in a solvent. A method of stirring, a method of fixing a thermoplastic resin (G) processed into a strand, a chip or a pellet as in a fixed bed system and circulating a solvent are included. After washing, the solvent is separated, and the remaining solvent is removed by distillation under reduced pressure or inert gas, whereby the thermoplastic resin (G) from which the oligomer has been removed is obtained. In this way, the thermoplastic resin (G) having an oligomer content of 6% by mass or less hardly causes the oligomer to elute from the resin and migrate to other materials even when retort sterilization is performed.

  Examples of the transition metal contained in the transition metal salt (H) include iron, nickel, copper, manganese, cobalt, rhodium, titanium, chromium, vanadium, and ruthenium. Among these, iron, nickel, copper, manganese, and cobalt are preferable, manganese or cobalt is more preferable, and cobalt is more preferable.

  The counter ion of the transition metal contained in the transition metal salt (H) is preferably an anion derived from an organic acid. Examples of the organic acid include acetic acid, stearic acid, dimethyldithiocarbamic acid, palmitic acid, and 2-ethylhexanoic acid. , Neodecanoic acid, linoleic acid, toluic acid, oleic acid, capric acid, naphthenic acid and the like. As the transition metal salt (H), cobalt 2-ethylhexanoate, cobalt neodecanoate and cobalt stearate are particularly preferable.

  The transition metal salt (H) is preferably 1 to 50,000 ppm in terms of transition metal, more preferably 5 to 10,000 ppm, based on the total mass of the modified EVOH (C) and the thermoplastic resin (G). More preferably, it mix | blends in 10-5,000 ppm. When the molded article of the present invention contains unmodified EVOH (D) in addition to the modified EVOH (C) and the thermoplastic resin (G), the transition metal salt (H) is modified EVOH (C), Based on the total mass of the thermoplastic resin (G) and the unmodified EVOH (D), 1 to 50,000 ppm, more preferably 5 to 10,000 ppm, more preferably 10 to 5, in terms of transition metal. It mix | blends in the range of 000 ppm. When the molded article of the present invention further contains a compatibilizer (I), the transition metal salt (H) is a modified EVOH (C), a thermoplastic resin (G), or an unmodified EVOH (D). And 1 to 50,000 ppm in terms of transition metal, more preferably 5 to 10,000 ppm, and still more preferably 10 to 5,000 ppm, based on the total mass of the compatibilizer (I). If the blending amount of the transition metal salt (H) is less than 1 ppm in terms of transition metal, the resulting molded product has insufficient oxygen absorption function. On the other hand, if it exceeds 50,000 ppm, the thermal stability decreases, and gel, May occur significantly.

  When the molded article of the present invention further contains unmodified EVOH (D) in addition to the thermoplastic resin (G) and the modified EVOH (C), the compatibility of these resins is improved, and the resulting molded article is obtained. For the purpose of giving a stable morphology, a compatibilizer (I) is contained as necessary. The type of the compatibilizer (I) is not particularly limited, and can be appropriately selected depending on the combination of the thermoplastic resin (G) and the modified EVOH (C) to be used.

  It is obtained by adding the compatibilizer (I) to improve the compatibility of the thermoplastic resin (G) with the modified EVOH (C) and, if necessary, the unmodified EVOH (D). The impact resistance and flexibility of the molded product can be further improved.

  Since the modified EVOH (C) and the unmodified EVOH (D) are highly polar resins, the compatibilizer (I) is preferably a hydrocarbon polymer containing a polar group. When the compatibilizer (I) is a hydrocarbon polymer containing a polar group, the compatibilizer (I), the thermoplastic resin (G), and Good affinity. Furthermore, the affinity between the compatibilizer (I) and the modified EVOH (C) or unmodified EVOH (D) is improved by the polar group of the compatibilizer (I). As a result, a stable morphology can be formed on the obtained molded body.

  Examples of monomers capable of forming a hydrocarbon polymer portion serving as a base of the hydrocarbon polymer containing the polar group include ethylene, propylene, 1-butene, isobutene, 3-methylpentene, 1-hexene, Α-olefins such as 1-octene; styrene, α-methylstyrene, 2-methylstyrene, 4-methylstyrene, 4-propylstyrene, 4-tert-butylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2 Styrenes such as ethyl-4-benzylstyrene, 4- (phenylbutyl) styrene, 2,4,6-trimethylstyrene, monofluorostyrene, difluorostyrene, monochlorostyrene, dichlorostyrene, methoxystyrene, tert-butoxystyrene; 1-vinylnaphthalene, 2-vinylnaphthalene And vinylnaphthalenes such as conjugated diene compounds such as butadiene, isoprene, 2,3-dimethylbutadiene, 1,3-pentadiene, and 1,3-hexadiene. One of these may contribute to the formation of the hydrocarbon polymer portion alone, or two or more monomers may contribute to the formation of the hydrocarbon polymer portion.

  The above monomers form the following hydrocarbon polymers: polyethylene (ultra low density polyethylene, low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene), polypropylene, ethylene-propylene copolymer Olefin polymers such as polymers; polystyrene, styrene-diene block copolymers (styrene-isoprene diblock copolymers, styrene-butadiene diblock copolymers, styrene-butadiene-styrene triblock copolymers, styrene -Isoprene-styrene triblock copolymer, etc.) and styrene polymers such as hydrogenated products thereof. Among these, styrene-diene block copolymers (styrene-isoprene diblock copolymer, styrene-butadiene diblock copolymer, styrene-butadiene-styrene triblock copolymer, styrene-isoprene-styrene triblock copolymer). Polymers etc.) and styrene polymers such as hydrogenated products thereof are preferred.

  Examples of polar groups include sulfur-containing groups such as sulfonic acid groups, sulfenic acid groups, and sulfinic acid groups; hydroxyl groups and epoxy groups; carbonyl group-containing groups such as ketone groups, ester groups, aldehyde groups, carboxyl groups, and acid anhydride groups; Nitrogen-containing groups such as nitro group, amide group, urea group and isocyanate group; phosphorus-containing groups such as phosphonic acid ester group and phosphinic acid ester group; boronic acid group, boronic acid ester group, boronic acid anhydride group, boronic acid And boron-containing groups such as bases.

  Among these, a carboxyl group and a boron-containing group are particularly preferable as the polar group when the compatibilizer (I) is a hydrocarbon polymer containing a polar group. Among these, when the polar group is a carboxyl group, the obtained molded product has high thermal stability. As mentioned above, when the transition metal salt (H) is excessively contained in the molded article of the present invention, its thermal stability may be reduced, but it is compatibilized having a carboxyl group together with the transition metal salt (H). When the agent (I) is contained, thermal stability is maintained.

  The method for producing a hydrocarbon-based polymer containing a polar group is not particularly limited. For example, the following methods can be mentioned: 1) The monomer capable of forming the hydrocarbon polymer portion is copolymerized with a monomer containing a polar group (or a group capable of forming the polar group). Method: 2) Method of using an initiator or a chain transfer agent having a polar group (or a group capable of forming the polar group) when polymerizing the monomer capable of forming the hydrocarbon polymer portion; 3) A method in which a monomer capable of forming the hydrocarbon polymer portion is subjected to living polymerization, and a monomer having a polar group (or a group capable of forming the polar group) is used as a terminator (terminal treatment agent); and 4 ) Polymerizing a monomer capable of forming the above hydrocarbon polymer portion to obtain a polymer, a reactive portion in the polymer, for example, a carbon-carbon double bond portion, a polar group (or the polar group) And a monomer having a group capable of forming a). In the method 1), when copolymerization is performed, any polymerization method of random copolymerization, block copolymerization, and graft copolymerization may be employed.

  Specific examples of the compatibilizer (I) having such a polar group are disclosed in detail in, for example, Patent Document 12. Among the disclosed compatibilizers (I), hydrogenated products of styrene-diene block copolymers having a boronic ester group are preferred. The compatibilizer (I) may be used alone or in combination of two or more.

  When the molded body of the present invention contains a thermoplastic resin (G) and a modified EVOH (C) as a resin component, when the total mass of the thermoplastic resin (G) and the modified EVOH (C) is 100% by mass, The thermoplastic resin (G) is preferably contained in a proportion of 1 to 30% by mass, and the modified EVOH (C) is preferably contained in a proportion of 70 to 99% by mass. More preferably, the thermoplastic resin (G) is 2 to 20% by mass and the modified EVOH (C) is 80 to 98% by mass. More preferably, the thermoplastic resin (G) is 3 to 15% by mass and the modified EVOH (C ) 85-97 mass%.

  When the molded product of the present invention contains a thermoplastic resin (G), a modified EVOH (C) and an unmodified EVOH (D) as the resin component, the thermoplastic resin (G) and the modified EVOH (C) When the total mass of unmodified EVOH (D) is 100 mass%, the thermoplastic resin (G) is 1 to 30 mass%, the modified EVOH (C) is 1 to 98 mass%, and the unmodified EVOH (D) Is preferably contained in a proportion of 1 to 98% by mass. More preferably, the thermoplastic resin (G) is 2 to 20% by mass, the modified EVOH (C) is 1 to 97% by mass, the unmodified EVOH (D) is 1 to 97% by mass, and more preferably the thermoplastic resin. (G) 3 to 15% by mass, modified EVOH (C) 1 to 96% by mass, and unmodified EVOH (D) 1 to 96% by mass.

  Further, when the molded product of the present invention contains a thermoplastic resin (G), a modified EVOH (C), an unmodified EVOH (D) and a compatibilizer (I) as a resin component, a thermoplastic resin (G ), Modified EVOH (C), unmodified EVOH (D) and compatibilizer (I) are 100% by mass, the thermoplastic resin (G) is 1 to 30% by mass, modified EVOH (C ) Is contained in an amount of 1-97.9% by mass, unmodified EVOH (D) is contained in an amount of 1-97.9% by mass, and the compatibilizer (I) is contained in an amount of 0.1-30% by mass. preferable. More preferably, the thermoplastic resin (G) is 2 to 20% by mass, the modified EVOH (C) is 1 to 96.8% by mass, the unmodified EVOH (D) is 1 to 96.8% by mass, the compatibilizer ( I) 0.2 to 20% by mass, more preferably 3 to 15% by mass of thermoplastic resin (G), 1 to 95.7% by mass of modified EVOH (C), 1 to 9% of unmodified EVOH (D) They are 95.7 mass% and compatibilizer (I) 0.3-10 mass%.

  When the ratio of the thermoplastic resin (G) is larger than 30% by mass, the gas barrier property against oxygen gas, carbon dioxide gas and the like of the obtained molded product tends to be lowered. On the other hand, when the ratio of the thermoplastic resin (G) is less than 1% by mass, the oxygen absorption function tends to be lowered.

  Various additives can be blended in the molded article of the present invention as necessary. Examples of such additives include sensitizers, curing agents, curing accelerators, antioxidants, plasticizers, ultraviolet absorbers, antistatic agents, colorants, and fillers. It can mix | blend in the range which does not inhibit the effect of invention. Specific examples of the additive include the following.

  Sensitizer: benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzyl diphenyl disulfide, tetramethyl thiuram monosulfide, azobisbutyronitrile, dibenzyl, diacetyl, acetophenone, 2,2-diethoxyacetophenone, benzophenone, 2-chlorothioxanthone, 2-methylthioxanthone and the like.

  Curing agents: methyl ethyl ketone peroxide, cyclohexane peroxide, cumene peroxide, benzoyl peroxide, dicumyl peroxide, t-butyl perbenzoate, and the like.

  Curing accelerator: amine such as methylaniline, dimethylaniline, diethylaniline, methyl-p-toluidine, dimethyl-p-toluidine, methyl-2-hydroxyethylaniline, di-2-hydroxyethyl-p-toluidine or hydrochloric acid thereof, Salts such as acetic acid, sulfuric acid and phosphoric acid.

  Antioxidant: 2,5-dibutyl-t-butylhydroquinone, 2,6-di-t-butyl-p-cresol, 4,4′-thiobis- (6-t-butylphenol), 2,2′-methylene -Bis- (4-methyl-6-butylphenol), octadecyl-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate, 4,4'-thiobis- (6-t- Butylphenol).

  Plasticizer: Dimethyl phthalate, diethyl phthalate, dibutyl phthalate, wax, liquid paraffin, phosphate ester, etc.

  UV absorber: ethylene-2-cyano-3,3′-diphenyl acrylate, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3′-t-butyl-) 5'-methylphenyl) 5-chlorotriazole, 2-hydroxy-4-methoxybenzophenone, (2,2'-dihydroxy-4-methoxybenzophenone) and the like.

  Antistatic agents: pentaerythritol monostearate, sorbitan monopalmitate, sulfated oleic acid, polyethylene oxide, carbowax and the like.

  Colorant: Carbon black, phthalocyanine, quinacridone, azo pigment, titanium oxide, bengara, etc.

  Filler: Glass fiber, mica, celite, calcium silicate, aluminum silicate, calcium carbonate, silicon oxide, montmorillonite, etc.

  The molding method for obtaining the molded product of the present invention to which an additive is added depending on the purpose is not particularly limited, and melt molding can be performed, or the molded product can be obtained by drying the solution. good. In the case of melt molding, each component may be supplied as it is to an extruder, melt kneaded and molded as it is. Each component may be melt-kneaded and pelletized once, and then molded, and a suitable means is appropriately employed.

  Although the molding temperature in melt molding varies depending on the melting point of each component, etc., the molten resin temperature is preferably about 120 ° C. to 250 ° C.

  As the melt molding method, any molding method such as an injection molding method, a compression molding method, and an extrusion molding method can be employed. Among these, examples of the extrusion molding method include a T-die method, a hollow molding method, a pipe extrusion method, a linear extrusion method, a modified die molding method, and an inflation method. The shape of the molded product is arbitrary, and may be not only pellets but also films, sheets, tapes, bottles, pipes, filaments, profile cross-section extrudates, and the like. Moreover, it is also possible to use the extrusion molded product obtained by the said extrusion molding method for secondary processes, such as uniaxial or biaxial stretching, or thermoforming.

  A preferred embodiment of the molded article of the present invention is a multilayer structure including a layer made of a resin composition containing a thermoplastic resin (G) and a modified EVOH (C). Specifically, it is a multilayer structure comprising the resin composition and having a layer in which at least a part of the resin composition is crosslinked and a layer made of a resin (F) other than the modified EVOH (C). .

  A method for producing a molded article made of such a multilayer structure is not particularly limited, and may be melt-molded, laminated using an adhesive or the like, or coated with a solution. In the case of melt molding, coextrusion molding, co-injection molding, extrusion coating, etc. are employed.

  The resin (F) is preferably a thermoplastic resin. Examples thereof include at least one selected from the group consisting of polyolefin, polyamide, polyester, polystyrene, polyurethane, polyvinylidene chloride, polyvinyl chloride, polyacrylonitrile, polycarbonate, acrylic resin and polyvinyl ester. Examples of polyolefins include low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer, ethylene-α-olefin (α-olefin having 3 to 20 carbon atoms) copolymer, ionomer, polypropylene, propylene ( [Alpha] -olefins having 4 to 20 carbon atoms) copolymers, polybutenes, polymethylpentenes and other olefins alone or copolymers, or these olefins alone or copolymers with unsaturated carboxylic acids or their anhydrides or esters. Examples include graft-modified ones. It is also preferable that the resin (F) is an elastomer.

  The layer structure of the multilayer structure includes C (C1, C2,...) As the layer made of the resin composition containing the thermoplastic resin (G) and the modified EVOH (C), and F (F1) as the resin (F) layer. , F2,..., When Ad is used as an adhesive layer provided as necessary, it is not only a two-layer structure of C / F, but also C / F / C, F if it is a film, sheet, or bottle shape. / C / F, F1 / F2 / C, F / C / F / C / F, C2 / C1 / F / C1 / C2, C / Ad / F, C / Ad / F / C, F / Ad / C / Ad / F, F / Ad / C / Ad / C / Ad / F, etc., and any configuration is possible. If filamentous, C and F are bimetal type, core (C) -sheath (F) type Any combination of core (F) -sheath (C) type or eccentric core-sheath type is possible. Moreover, the resin which improves the adhesiveness of both resin may be mix | blended.

  The molded product of the present invention is a product in which at least a part of the resin composition is crosslinked, and is produced by crosslinking at least a part of the resin composition that is a molded product obtained as described above. can do. Although the above-mentioned molded product before cross-linking can be cross-linked by leaving it in the air for a long time, usually, the molded product before cross-linking is obtained from electron beam, X-ray, γ-ray, ultraviolet ray and visible light. It is preferable to perform crosslinking by irradiating at least one selected from the group consisting of or heating.

  When an electron beam, X-ray or γ-ray is used, the absorbed dose is preferably 1 kGy or more. It is more preferably 1 kGy to 1 MGy, further preferably 5 kGy to 500 kGy, and particularly preferably 10 kGy to 200 kGy. When the absorbed dose is larger than 1 MGy, EVOH is decomposed, which causes problems such as a significant decrease in strength and coloring. On the other hand, when the absorbed dose is smaller than 1 kGy, desired performance such as hot water resistance cannot be obtained.

  As described above, when the molded article is crosslinked by irradiating it with an electron beam or the like, the side chain double bond of the modified EVOH (C) contributes to the crosslinking reaction. At this time, there is a concern that the double bond contained in the thermoplastic resin (G) also undergoes a crosslinking reaction, the double bond disappears, and the oxygen absorption performance is lowered. However, in the molded article of the present invention, when a thermoplastic resin (G) having a carbon-carbon double bond substantially only in the main chain is used, surprisingly, even after electron beam irradiation, oxygen No decrease in absorption performance was observed. The reason for this is not clear, but the carbon-carbon double bond present in the main chain is more reactive to radicals generated by irradiation with electron beams or the like than the carbon-carbon double bond present in the side chain. It is presumed that the absorbed dose as described above is not involved in the reaction.

  In addition, when the molded product of the present invention is a multilayer structure and is characterized by performing heat sterilization after filling the contents, as described above, improvement in hot water resistance causes whitening, deformation, and deterioration of barrier properties. It becomes difficult to occur. When this multi-layer structure is used as a food packaging material, suitable applications include lid materials, pouches, vacuum packaging, skin packs, deep-drawing packaging, rocket packaging, etc. Alternatively, it exhibits excellent performance as a tray-type container. Moreover, it can also process into a bottle shape or a tube shape. Further, when the molded product of the present invention is used as a packaging material for retort, in addition to suppressing the occurrence of the above-mentioned whitening, deformation, and decrease in barrier properties, in order to improve impact resistance and flexibility, Occurrence can be suppressed.

  A package having excellent storage stability can be obtained by filling the multilayer structure with the contents and then subjecting it to heat sterilization, particularly retort sterilization. For the retort sterilization treatment, various methods such as a recovery method, a replacement method, a steam method, a shower method, and a spray method are adopted. Immediately after the retort sterilization treatment, the packaging material obtained from the molded product of the present invention may become white and opaque, but after removing the surface water of the packaging material, it is made transparent by leaving it for a while. In the case where desiccation and gas barrier properties are desired to be restored more reliably, it is preferable to dry at 40 to 150 ° C. for 1 to 120 minutes. Other heat sterilization methods include a hot filling method.

  Applications of the molded article of the present invention are diverse. For example, extrusion molded products, thermoformed products, profiled molded products, extrusion blow molded products, injection molded products, flexible packaging materials, films, sheets, pipes, hoses, containers (particularly retort packaging containers) and the like are exemplified as suitable ones. The When the molded product is a multilayer structure, a coextruded film or sheet, a heat shrink film, a multilayer pipe (especially a fuel pipe or a hot water circulation pipe), a multilayer hose (especially a fuel hose), a multilayer container (especially a co-extruded film). Extrusion blow molding containers, co-injection molding containers, retort packaging containers, etc.) are exemplified as suitable ones. Especially, it is used especially suitably as a packaging material for retorts and a lid material for retorts.

  Hereinafter, the present invention will be specifically described with reference to examples and the like, but the present invention is not limited thereto. Analysis and evaluation in the following examples and comparative examples were performed as follows.

[1] Molecular structure of thermoplastic resin (G):
It was determined by ¹ H-NMR (nuclear magnetic resonance) measurement (using “JNM-GX-500” manufactured by JEOL Ltd.) using CDCl ₃ as a solvent.

[2] Number average molecular weight and weight average molecular weight of the thermoplastic resin (G):
The measurement was performed by gel permeation chromatography (GPC) and expressed as a polystyrene converted value. Detailed measurement conditions are as follows.
<Analysis conditions>
Apparatus: Shodex gel permeation chromatography SYSTEM-11
Column: KF-806L (Shodex), column temperature: 40 ° C
Mobile phase: Tetrahydrofuran, Flow rate: 1.0 ml / min Detector: RI, Filtration: 0.45 μm filter, Concentration: 0.1%

[3] Ethylene content and saponification degree of unmodified EVOH (A) and unmodified EVOH (D):
It was calculated by ¹ H-NMR (nuclear magnetic resonance) measurement using DMSO-d ₆ (using “JNM-GX-500” manufactured by JEOL Ltd.).

[4] Degree of modification of modified EVOH (C) A sample used for measurement was pulverized, a low molecular weight component was extracted with acetone, and then dried at 120 ° C for 12 hours. The sample is subjected to ¹ H-NMR measurement (using “JNM-GX-500” manufactured by JEOL Ltd.) using DMSO-d ₆ as a solvent, and an epoxy compound having a double bond is obtained in the obtained spectrum. The peak of methine position of double bond of reacted modified EVOH (5.9 ppm) or the peak of methylene position of double bond (5.2 ppm) and the peak of ethylene portion corresponding to the monomer unit of EVOH (1.4 ppm) The area ratio was calculated.

[5] Melt flow rate (MFR) of unmodified EVOH (A), unmodified EVOH (D) and modified EVOH (C)
Using a melt indexer L260 (manufactured by Techno Seven Co., Ltd.), the resin flow rate (g / 10 min) was measured at a load of 2.16 kg and a temperature of 190 ° C.

[6] Retort suitability (evaluation with a single layer film)
The film obtained by irradiating the electron beam or the film not irradiated with the electron beam obtained in each Example and Comparative Example was subjected to retort sterilization at 120 ° C. for 90 minutes, and the state of the film immediately after that was visually observed. Was evaluated as follows.
A: There is no dissolution of the film.
B: The film is slightly dissolved.
C .... The film dissolves, leaving no shape.

[7] Retort suitability (evaluation with multilayer film)
From the multilayer film obtained in each Example and Comparative Example, a pouch in which three sides were heat-sealed was prepared, water was added, and the remaining one side was heat-sealed and sealed to enclose water. Got. This pouch was subjected to retort sterilization at 120 ° C. for 90 minutes, and the state of the multilayer film immediately after that was visually evaluated as follows.
A: No whitening or delamination of film.
B: Whitening or delamination of the film is observed.

[8] Film impact (impact resistance)
The films obtained in each Example and Comparative Example were cut into 10 cm × 10 cm and conditioned at 23 ° C. and 50% RH. Using a film impact tester manufactured by Toyo Seiki Co., Ltd. under the same atmosphere, a 0.6 inch hemisphere was projected in the center of the film, and the value when the film was broken was measured.

[9] Flexibility (flexibility)
The films obtained in each Example and Comparative Example were cut into 210 mm × 297 mm and conditioned at 23 ° C. and 50% RH. Using a humidity-controlled film, make a cylindrical shape with a diameter of 3.5 inches under the same atmosphere, and fix both ends to a gelbo flex tester (manufactured by Rigaku Kogyo Co., Ltd.). A pitch of 440 degrees is added at the first 3.5 inches of the stroke, and a twist of 440 degrees is added for the first 2.5 inches of the stroke, and then the reciprocating motion of the linear and horizontal motion is repeated a certain number of times for one and two pinholes. The number of bendings that occurred was used as an index of bending resistance. It shows that as the number of times of bending until one pinhole is generated is increased, the bending resistance is excellent and the flexibility is excellent.

Synthesis Example 1 Synthesis of Thermoplastic Resin (G) (Polyoctenylene (G-1)) A 5-liter three-necked flask equipped with a stirrer and a thermometer was purged with nitrogen, and then 110 g of cyclooctene (1. 0 mol) and 624 g of heptane in which 187 mg (1.7 mmol) of cis-4-octene was dissolved. Next, a catalyst solution in which 8.48 mg (10 μmol) of benzylidene (1,3-dimesitylimidazolidine-2-ylidene) (tricyclohexylphosphine) ruthenium dichloride was dissolved in 1 g of toluene was prepared, and this was prepared using the above heptane solution. In addition, ring-opening metathesis polymerization was performed at 70 ° C. After 5 minutes, analysis by gas chromatography (manufactured by Shimadzu Corporation, GC-14B; column: manufactured by Chemical Inspection Association, G-100) confirmed the disappearance of cyclooctene. After adding 600 g of methanol to the obtained reaction liquid and stirring for 30 minutes at 40 ° C., the mixture was allowed to stand at 40 ° C. for 1 hour for liquid separation to remove the lower layer. After adding 600 g of methanol to the upper layer again and stirring at 40 ° C. for 30 minutes, the mixture was allowed to stand at 40 ° C. for 1 hour for liquid separation to remove the lower layer. Low boiling components such as heptane are distilled off from the upper layer under reduced pressure, and further dried at 50 Pa and 40 ° C. for 24 hours using a vacuum dryer, and contains an oligomer having a weight average molecular weight of 158,000 and a molecular weight of 1,000 or less. 101.2 g (yield 90%) of polyoctenylene having a rate of 8.5% was obtained. The ratio of the obtained polyoctenylene to the total carbon-carbon double bonds of the carbon-carbon double bonds in the side chain was 0%. In addition, the ratio with respect to this total carbon-carbon double bond is the amount of the carbon-carbon double bond in the main chain a (mol / g), and the amount of the carbon-carbon double bond in the side chain is b (mol). / G), 100 × b / (a + b).

  The total amount of polyoctenylene thus obtained was crushed to about 1 mm square, placed in a 500 ml separable flask equipped with a stirrer, a reflux tube and a thermometer, added with 300 g of acetone, and stirred at 40 ° C. for 3 hours. Acetone was removed by decantation, 300 g of acetone was added again, and the mixture was stirred at 40 ° C. for 3 hours. Acetone is removed by decantation, and then dried at 50 Pa and 100 ° C. for 6 hours using a vacuum dryer. Polyoctenylene having a weight average molecular weight of 163,000 and a molecular weight of 1,000 or less is 3.1%. (G-1) 96.1 g was obtained.

Synthesis Example 2 Synthesis of Compatibilizer (I) Weight average molecular weight 100,400, styrene / butadiene = 18/82 (mass ratio), 1,2-bond / 1,4-bond molar ratio of butadiene units = Styrene-butadiene-styrene having 47/53, hydrogenation rate of 97%, carbon-carbon double bond amount of 430 μmol / g, melt flow rate of 5 g / 10 min (230 ° C., 2160 g load), density of 0.89 g / cm ³ The hydrogenated triblock copolymer was supplied to the same-direction twin-screw extruder TEM-35B (manufactured by Toshiba Machine) at a rate of 7 kg / hr while replacing the inlet with nitrogen at 1 liter / min. The configuration and operating conditions of the twin screw extruder used for the reaction are as follows. Screw diameter: 37 mmφ, L / D: 52 (15 blocks), liquid feeder: C3 (liquid feeder 1) and C11 (liquid feeder 2), vent position: C6 (vent 1) and C14 (vent 2), screw configuration: Seal rings are used between C5-C6, C10-C11, and C12. Temperature setting: C1 (water cooling), C2-C3 (200 ° C), C4-C15 (250 ° C), die (250 ° C), screw Number of revolutions: 400 rpm. Next, a liquid mixture (TEAB / BBD = 29/71, mass ratio) of borane-triethylamine complex (TEAB) and boric acid 1,3-butanediol ester (BBD) is supplied from the liquid feeder 1 at a rate of 0.6 kg / hr. Then, 1,3-butanediol was supplied from the liquid feeder 2 at a rate of 0.4 kg / hr and continuously kneaded. During kneading, the pressure was adjusted so that the gauges of Vent 1 and Vent 2 showed about 2.7 kPa. As a result, a hydrogenated product of a modified styrene-butadiene-styrene triblock copolymer containing a boronic acid 1,3-butanediol ester group (BBDE) (compatibility agent (BB) at a rate of 7 kg / hr from the discharge port. I-1)) was obtained. The amount of boronic acid 1,3-butanediol ester group in the compatibilizer (I-1) was 210 μmol / g.

Synthesis Example 3 Synthesis of Modified EVOH (C) -1
28 parts by mass of zinc acetylacetonate monohydrate was mixed with 957 parts by mass of 1,2-dimethoxyethane to obtain a mixed solution. To this mixed liquid, 15 parts by mass of trifluoromethanesulfonic acid was added with stirring to obtain a catalyst solution.

  A TEM-35BS extruder (37 mmφ, L / D = 52.5) manufactured by Toshiba Machine Co., Ltd. was used, and a screw, three vents, and three pressure inlets were installed. The resin feed port was cooled with water, the temperature of the screw rotation portion was set to 200 ° C., and the operation was performed at a screw rotation speed of 300 rpm. EVOH (ethylene content 32 mol%, MFR 6.0 g / 10 min, potassium content 8 ppm, phosphate group content 20 ppm, saponification degree 99 mol% or more) is charged at 20.0 kg / hr from the resin feed port. Allyl glycidyl ether (AGE) was added from the pressure inlet at a rate of 1.76 kg / hr and the catalyst solution at a rate of 0.2 kg / hr. Sodium acetate 0.82% aqueous solution was added at a rate of 0.3 kg / hr from the second pressure inlet. Excess AGE was removed from the first vent under reduced pressure, water was added at a rate of 1 kg / hr from the third pressure inlet, and water and AGE were removed from the second and third vents under reduced pressure. As a result, a modified EVOH having an AGE modification amount of 1.0 mol%, an MFR of 2.0 g / 10 minutes, and a melting point of 171 ° C. (hereinafter referred to as modified EVOH (C-1)) was obtained. The obtained results are summarized in Table 1.

Synthesis Example 4 Synthesis of Modified EVOH (C) -2
A TEM-35BS extruder (37 mmφ, L / D = 52.5) manufactured by Toshiba Machine Co., Ltd. was used, and a screw, three vents, and three pressure inlets were installed. The resin feed port was cooled with water, the temperature of the screw rotation portion was set to 200 ° C., and the operation was performed at a screw rotation speed of 300 rpm. EVOH (ethylene content 32 mol%, MFR 6.0 g / 10 min, potassium content 8 ppm, phosphate group content 20 ppm, saponification degree 99 mol% or more) is charged at 20.0 kg / hr from the resin feed port. Allyl glycidyl ether (AGE) was added from the pressure inlet at a rate of 2.93 kg / hr, and the catalyst solution at a rate of 0.5 kg / hr. Sodium acetate 0.82% aqueous solution was added at a rate of 0.6 kg / hr from the second pressure inlet. Excess AGE was removed from the first vent under reduced pressure, water was added at a rate of 1 kg / hr from the third pressure inlet, and water and AGE were removed from the second and third vents under reduced pressure. As a result, a modified EVOH (hereinafter referred to as modified EVOH (C-2)) having an AGE modification amount of 1.7 mol%, an MFR of 2.0 g / 10 min, and a melting point of 166 ° C. was obtained. The obtained results are summarized in Table 1.

Example 1
(1) 8 parts by mass of polyoctenylene (G-1) obtained in Synthesis Example 1, 91 parts by mass of modified EVOH (C-1) obtained in Synthesis Example 3, and the compatibilizing agent (I -1) 1 part by mass and 0.42 part by mass of cobalt stearate (II) (400 ppm as cobalt atoms) were dry blended, and a 30 mmφ twin screw extruder (TEX-30SS-30CRW-2V manufactured by Nippon Steel Works) Was used, and the inside of the cylinder was melt-kneaded while purging with nitrogen, and pelletized using a pelletizer.

(2) The above pellets were melt-extruded from a coat hanger while purging the inside of the cylinder with nitrogen at 220 ° C. using a 20φ single screw extruder to obtain a single layer film having a thickness of 20 μm. This single layer film was irradiated with an electron beam of 100 kGy (acceleration voltage 200 kV) in a nitrogen atmosphere to crosslink the modified EVOH (C-1) in the film. The film after electron beam irradiation was subjected to retort sterilization treatment at 120 ° C. for 90 minutes. As a result, the film was not dissolved and the form was good.

(3) About 0.2 g of the film after electron beam irradiation obtained above was precisely weighed and placed in a standard bottle with an internal capacity of 85 ml filled with air at 23 ° C. and 50% RH. The air in the standard bottle contained 21:79 oxygen and nitrogen in a volume ratio. In order to set the internal relative humidity to 100% RH, a filter paper containing water was enclosed, the mouth of the standard bottle was sealed with an epoxy resin using a multilayer sheet containing an aluminum layer, and then allowed to stand at 60 ° C. After sealing, the internal air was sampled with a syringe over time, and the oxygen concentration of this air was measured using gas chromatography. The holes vacated in the multilayer sheet at the time of sampling were sealed with epoxy resin each time. The amount of oxygen absorbed under a 60 ° C., 100% RH atmosphere was determined by calculating the amount of oxygen decrease from the volume ratio of oxygen and nitrogen obtained by the measurement. The amount of oxygen absorbed (integrated amount) 30 days after the encapsulation was 61.5 cc / g.

(4) The film obtained after the electron beam irradiation (hereinafter referred to as E) obtained above is used as an intermediate layer, and a stretched polyamide film “EMBLEM ONBC” (trade name, Unitika Ltd., thickness 15 μm) on one surface thereof. ; Hereinafter simply abbreviated as ON) and unstretched polypropylene “RXC-18 # 60” (trade name, manufactured by Tosero Co., Ltd., thickness 60 μm; hereinafter simply abbreviated as CPP) on the opposite surface Adhesive (Takelac A385 (trade name, Takeda Pharmaceutical Company Limited): Takenate A50 (trade name, Takeda Pharmaceutical Company Limited): ethyl acetate = 24: 4: 53 (mass ratio); hereinafter simply referred to as Ad) And a multilayer film having a layer structure of ON / Ad / E / Ad / CPP was obtained. A bag having three sides heat-sealed was prepared from the multilayer film, and after water was added, the remaining one side was heat-sealed and sealed to obtain a pouch filled with water. When this pouch was subjected to a retort sterilization treatment at 120 ° C. for 90 minutes, no peeling between the intermediate layer and the inner and outer layers was confirmed, and the transparency of the intermediate layer was maintained.

(5) Sampling the multilayer film from the pouch after retort sterilization obtained by the same method as in (4) above, and measuring oxygen permeation amount (OTR) immediately after retort, after 1 day and after 1 month, It was less than the detection limit of 0.1 cc / m ² · day · atm, indicating excellent oxygen barrier properties. For OTR measurement, the sample was mounted under the conditions of 20 ° C. and 65/100% RH so that the ON side of the multilayer film was 65% RH and oxygen gas atmosphere, and the CPP side was 100% RH and nitrogen atmosphere. Measured. For the OTR measurement, a plurality of pouches subjected to retort sterilization in (4) above were prepared and stored under the same conditions, the bags were disassembled at a predetermined time, the multilayer film was taken out, and subjected to OTR measurement. The above results are summarized in Table 2.

(Example 2)
(1) 8 parts by mass of polyoctenylene (G-1) obtained in Synthesis Example 1, 45.5 parts by mass of modified EVOH (C-2) obtained in Synthesis Example 4, and “Eval F171B” (product) Name, manufactured by Kuraray Co., Ltd., ethylene content 32 mol%, MFR 1.6 g / 10 min (190 ° C., 2160 g load), saponification degree 99 mol% or more) 45.5 parts by mass, phase obtained in Synthesis Example 2 1 part by mass of a solubilizer (I-1) and 0.42 part by mass of cobalt stearate (II) (400 ppm as cobalt atoms) were dry blended, and a 30 mmφ twin screw extruder (TEX-30SS, manufactured by Nippon Steel Works) 30CRW-2V), the inside of the cylinder was melt-kneaded while purging with nitrogen, and pelletized using a pelletizer.

(2) The above pellets were melt-extruded from a coat hanger while purging the inside of the cylinder with nitrogen at 220 ° C. using a 20φ single screw extruder to obtain a single layer film having a thickness of 20 μm. This single layer film was irradiated with an electron beam of 100 kGy (acceleration voltage 200 kV) under a nitrogen atmosphere to crosslink the modified EVOH (C-2) in the film. The film after electron beam irradiation was subjected to retort sterilization treatment at 120 ° C. for 90 minutes. As a result, the film was not dissolved and the form was good.

(3) About 0.2 g of the film after electron beam irradiation obtained above was precisely weighed, and in the same manner as in Example 1 (3), at 60 ° C. in a 100% RH atmosphere, 30 days after the encapsulation. The amount of oxygen absorbed (integrated amount) was determined to be 62 cc / g.

(4) A multilayer film was obtained in the same manner as in Example 1 (4) using the film obtained as described above after irradiation with an electron beam as an intermediate layer. From this multilayer film, a pouch filled with water was obtained in the same manner as in Example 1 (4). When this pouch was subjected to retort sterilization at 120 ° C. for 90 minutes, no peeling between the intermediate layer and the inner and outer layers was confirmed. The transparency of the intermediate layer was maintained.

(5) Sampling the multilayer film from the pouch after retort sterilization obtained by the same method as in (4) above, and measuring oxygen permeation amount (OTR) immediately after retort, after 1 day and after 1 month, It was less than the detection limit of 0.1 cc / m ² · day · atm, indicating excellent oxygen barrier properties. For OTR measurement, the sample was mounted under the conditions of 20 ° C. and 65/100% RH so that the ON side of the multilayer film was 65% RH and oxygen gas atmosphere, and the CPP side was 100% RH and nitrogen atmosphere. Measured. For the OTR measurement, a plurality of pouches subjected to retort sterilization in (4) above were prepared and stored under the same conditions, the bags were disassembled at a predetermined time, the multilayer film was taken out, and subjected to OTR measurement. The above results are summarized in Table 2.

(Examples 3 to 10)
In Example 2 (1), instead of “Eval F171B” as unmodified EVOH, “Eval L171B” (trade name, manufactured by Kuraray Co., Ltd., ethylene content 27 mol%, MFR 4.1 g / 10 min (210 ° C., 2160 g) Except that the pellets were prepared at the blending mass ratio described in Table 2 using the load) and the saponification degree of 99 mol% or more, and the electron beam irradiation amount in Example 2 (2) was set to the value described in Table 2. In the same manner as in Example 2, the oxygen absorption amount of the single-layer film after electron beam irradiation, retort suitability evaluation, creation of a multilayer film and creation of a pouch filled with water, retort sterilization treatment of the pouch, and subsequent oxygen permeation amount (OTR) measurement was performed. The above results are summarized in Table 2.

(Comparative Examples 1-5)
In Example 2 (1), instead of “Eval F171B” as unmodified EVOH, “Eval L171B” (trade name, manufactured by Kuraray Co., Ltd., ethylene content 27 mol%, MFR 4.1 g / 10 min (210 ° C., 2160 g) Load) and a saponification degree of 99 mol% or more), pellets were prepared at the blending mass ratios described in Table 2, and the electron beam irradiation amount in Example 2 (2) was set to the values described in Table 2 ( Except that the electron beam may not be irradiated), the oxygen absorption amount of the film after irradiation with the electron beam, evaluation of retort suitability, creation of a multilayer film, and creation of a pouch enclosing water, pouch The retort sterilization treatment and the subsequent oxygen permeation (OTR) measurement were performed. The above results are summarized in Table 2.

(Example 11)
When the film impact was measured using the film after electron beam irradiation obtained in Example 4, it was 2.8 kg-cm. The film was subjected to retort sterilization at 120 ° C. for 90 minutes, and the film impact was measured at 23 ° C. and 50% RH. The result was 2.8 kg-cm.

  When the above-mentioned film after electron beam irradiation was used and a bending resistance (flexibility) test was conducted with a gelbo flex tester, the number of bendings until one pinhole was generated was 70 times. The results are summarized in Table 3.

(Comparative Example 6)
A film impact measurement and a bending resistance (flexibility) test were conducted in the same manner as in Example 11 except that the film after electron beam irradiation obtained in Comparative Example 2 was used. However, since the film was dissolved and the shape was not left by the retort sterilization treatment, the film impact measurement after the retort sterilization treatment was not performed. The results are summarized in Table 3.

(Comparative Example 7)
A film impact measurement and a bending resistance (flexibility) test were performed in the same manner as in Example 11 except that the film after electron beam irradiation obtained in Comparative Example 3 was used. The results are summarized in Table 3.

(Comparative Example 8)
A film impact measurement and a bending resistance (flexibility) test were performed in the same manner as in Example 11 except that the film after electron beam irradiation obtained in Comparative Example 5 was used. However, since the film was dissolved by the retort sterilization treatment and the shape did not remain, the film impact evaluation after the retort sterilization treatment was not performed. The results are summarized in Table 3.

Claims (16)

A retort packaging material comprising a multilayer structure comprising a layer comprising a resin composition comprising a thermoplastic resin (G) having a carbon-carbon double bond and a modified ethylene-vinyl alcohol copolymer (C). The modified ethylene-vinyl alcohol copolymer (C) is obtained by modifying an unmodified ethylene-vinyl alcohol copolymer (A) with an epoxy compound (B) having a double bond. The amount of modification by the epoxy compound (B) having a double bond is 0.1 to 10 mol% based on the monomer unit of the unmodified ethylene-vinyl alcohol copolymer (A), and the resin composition A packaging material for retort , characterized in that at least a part thereof is crosslinked. The packaging material for retorts according to claim 1, wherein the thermoplastic resin (G) having a carbon-carbon double bond has a carbon-carbon double bond substantially only in the main chain. The retort packaging material according to claim 2, wherein the thermoplastic resin (G) is polyoctenylene. The packaging material for retorts according to any one of claims 1 to 3, wherein the resin composition further contains an unmodified ethylene-vinyl alcohol copolymer (D). The retort packaging material according to any one of claims 1 to 4, wherein the resin composition further contains a transition metal salt (H). The retort packaging material according to claim 5, wherein the transition metal salt (H) is a cobalt salt. The retort packaging material according to any one of claims 1 to 6, wherein the resin composition further contains a compatibilizer (I). The packaging material for retorts according to any one of claims 1 to 7, wherein the epoxy compound (B) having a double bond is allyl glycidyl ether. It is a film or a sheet | seat, The packaging material for retorts in any one of Claims 1-8. It is a lid material for retorts, The packaging material for retorts in any one of Claims 1-9 . It is a pouch, The packaging material for retorts in any one of Claims 1-9. At least one of a step of mixing a thermoplastic resin (G) and a modified ethylene-vinyl alcohol copolymer (C) to produce a resin composition, a step of molding the resin composition, and a molded resin composition The manufacturing method of the packaging material for retorts in any one of Claims 1-11 which has the process of bridge | crosslinking a part. The manufacturing method of the packaging material for retorts of Claim 12 which mixes an unmodified | denatured ethylene-vinyl alcohol-type copolymer (D) further, when manufacturing the said resin composition. The manufacturing method of the packaging material for retorts of Claim 12 or 13 which mixes a transition metal salt (H) further, when manufacturing the said resin composition. The manufacturing method of the packaging material for retorts in any one of Claims 12-14 which mixes compatibilizer (I) further, when manufacturing the said resin composition. Electron beams, X-rays, gamma rays, or irradiated with at least one member selected from the group consisting of ultraviolet and visible light, according to claim 12 to 15 to crosslink at least a portion of the resin composition is molded by heating The manufacturing method of the packaging material for retorts in any one of these.