JP2014198799A - Oxygen-absorbing resin composition and oxygen-absorbing laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oxygen-absorbing resin composition and an oxygen-absorbing laminate, which have excellent oxygen-absorbing property and can be used suitably for forming a packaging material used for packing contents such as food, beverage, medicine, and the like which deteriorate in the presence of oxygen.SOLUTION: The oxygen-absorbing resin composition comprises an oxygen-absorbing resin comprising a cyclized conjugated diene polymer and a base resin comprising at least one thermoplastic resin selected from polyolefins and aliphatic polyamides, wherein a content of calcium stearate, as a content of calcium element derived from the calcium stearate, is 5 μg/g or less. The oxygen-absorbing laminate comprises an oxygen-absorbing layer comprising the oxygen-absorbing resin composition and a neighboring resin layer comprising a thermoplastic resin laminated on the oxygen-absorbing layer, wherein a content of calcium stearate of the neighboring resin layer, as a content of calcium element derived from the calcium stearate, is 20 μg/g or less.

Description

  The present invention relates to an oxygen-absorbing resin composition and an oxygen-absorbing laminate, and more particularly, for packaging contents that have excellent oxygen-absorbing properties and deteriorate due to the presence of oxygen, such as foods, beverages, and pharmaceuticals. The present invention relates to an oxygen-absorbing resin composition and an oxygen-absorbing laminate that are suitably used for constituting the packaging material.

  Foods, beverages, pharmaceuticals, and the like are required to be stored so as not to come into contact with oxygen as much as possible because quality deterioration occurs when they come into contact with oxygen. Therefore, an inert gas such as nitrogen is also filled in a container or package for storing foods, beverages, pharmaceuticals, and the like. However, this method has a problem that the cost is increased at the time of manufacturing, and once the bag is opened, air flows in from the outside, and it is impossible to prevent quality deterioration thereafter. For this reason, various studies have been conducted on techniques for removing oxygen remaining in containers or packaging.

  In recent years, as a technique for removing oxygen, a technique in which a container or package is formed using a resin material having oxygen absorbability and oxygen is absorbed by the container or the package itself has attracted attention. Various types of resin materials having oxygen absorptivity have been studied. As one of widely used resin materials, for example, as described in Patent Document 1, a resin that can undergo an oxidation reaction is used. Examples include those to which a transition metal catalyst such as a transition metal salt that promotes an oxidation reaction is added.

  However, a resin material having an oxygen absorptivity to which a transition metal catalyst is added has a problem that a strong odor is likely to be generated with the absorption of oxygen. Oxygen-absorbing resin materials are used as containers and packaging for foods, beverages, pharmaceuticals, and the like, so the generation of odor is a serious problem.

  Then, utilization of resin which can exhibit oxygen absorptivity without mix | blending a transition metal catalyst is examined. For example, in Patent Document 2, when a polyester resin having a specific alicyclic structure is subjected to radiation treatment, it exhibits oxygen absorbing ability without blending a transition metal catalyst, and is suitably used as a material for an oxygen-absorbing container. It is disclosed that an oxygen-absorbing resin can be obtained. Further, in Patent Document 3, the conjugated diene polymer cyclized product exhibits oxygen absorbing ability without blending a transition metal catalyst, and is suitably used as a material for oxygen-absorbing molded articles such as packaging containers. It is disclosed.

  However, the materials disclosed in Patent Document 2 and Patent Document 3 tend to have insufficient oxygen absorption capacity as compared with the oxygen-absorbing resin material to which a transition metal catalyst is added. Therefore, for these materials, investigations for improving the oxygen absorption ability are performed without blending a transition metal catalyst. For example, in Patent Document 4, based on the knowledge that an antioxidant adversely affects the oxygen absorption performance of an oxygen-absorbing resin, in an oxygen-absorbing layer made of an oxygen-absorbing resin and a layer laminated adjacent thereto, the antioxidant is prevented. An oxygen-absorbing multilayer body in which the content of each agent is not more than a specific value has been proposed.

JP 2001-106866 A International Publication No. 2005/105887 International Publication No. 2007/094247 JP 2009-12443 A

  However, even the oxygen-absorbing multilayer body disclosed in Patent Document 4 may lack its oxygen-absorbing ability, and further improvements have been desired.

  Accordingly, the present invention provides an oxygen-absorbing resin that has an excellent oxygen-absorbing property and that is suitably used to construct a packaging material for packaging contents that deteriorate due to the presence of oxygen, such as foods, beverages, and pharmaceuticals. An object is to provide a composition and an oxygen-absorbing laminate.

  As a result of diligent research to achieve the above object, the present inventors have found that calcium stearate blended as a lubricant in many commercially available resins tends to inhibit oxygen absorption of conjugated diene polymer cyclized products. I found out. And when a conjugated diene polymer cyclized product and polyolefin or aliphatic polyamide are mixed to constitute an oxygen-absorbing resin composition, a layer of the oxygen-absorbing resin composition and a layer made of another resin are laminated. In the case of constituting an oxygen-absorbing laminate, if the other resin that is substantially free of calcium stearate is selected and used, the oxygen-absorbing ability of the oxygen-absorbing resin composition is remarkably improved. I found. The present invention has been completed based on this finding.

  Thus, according to the present invention, an oxygen-absorbing resin that is a conjugated diene polymer cyclized product and a base resin that is at least one thermoplastic resin selected from polyolefins and aliphatic polyamides, Is provided as an oxygen-absorbing resin composition having a calcium element content derived from calcium stearate of 5 μg / g or less.

  In the above oxygen-absorbing resin composition, the antioxidant content is preferably 200 μg / g or less.

  Moreover, according to the present invention, an oxygen-absorbing laminate comprising an oxygen-absorbing layer comprising the above-described oxygen-absorbing resin composition and an adjacent resin layer comprising a thermoplastic resin laminated on the oxygen-absorbing layer. An oxygen-absorbing laminate in which the content of calcium stearate in the adjacent resin layer is 20 μg / g or less as a calcium element content derived from calcium stearate is provided.

  In the oxygen-absorbing laminate, it is preferable that the antioxidant content of the adjacent resin layer is 500 μg / g or less.

  According to the present invention, an oxygen-absorbing resin that has an excellent oxygen-absorbing property and is suitably used for constituting a packaging material for packaging contents that deteriorate due to the presence of oxygen, such as foods, beverages, and pharmaceuticals. Compositions and oxygen-absorbing laminates are provided.

  The oxygen-absorbing resin composition of the present invention comprises an oxygen-absorbing resin that is a conjugated diene polymer cyclized product, and a base resin that is at least one thermoplastic resin selected from polyolefins and aliphatic polyamides. Is. In the oxygen-absorbing resin composition of the present invention, the conjugated diene polymer cyclized product used as the oxygen-absorbing resin is obtained by subjecting the conjugated diene polymer to a cyclization reaction in the presence of an acid catalyst. It has a ring structure containing at least one carbon-carbon double bond.

  The conjugated diene polymer used for obtaining the conjugated diene polymer cyclized product includes a conjugated diene monomer homopolymer, a copolymer of two or more conjugated diene monomers, and a conjugated diene monomer. Copolymers with other monomers copolymerizable with this can be used. The conjugated diene monomer is not particularly limited, and specific examples thereof include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-phenyl-1,3-butadiene, 1, Examples include 3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 4,5-diethyl-1,3-octadiene, and 3-butyl-1,3-octadiene. These monomers may be used individually by 1 type, and may be used in combination of 2 or more type.

  Examples of other monomers copolymerizable with the conjugated diene monomer include styrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, 2,4-dimethylstyrene, ethylstyrene, and p-tert. Fragrances such as butyl styrene, α-methyl styrene, α-methyl-p-methyl styrene, o-chloro styrene, m-chloro styrene, p-chloro styrene, p-bromo styrene, 2,4-dibromo styrene, vinyl naphthalene Group vinyl monomers, chain olefin monomers such as ethylene, propylene and 1-butene, cyclic olefin monomers such as cyclopentene and 2-norbornene, 1,5-hexadiene, 1,6-heptadiene, 1,7 Non-conjugated diene monomers such as octadiene, dicyclopentadiene, 5-ethylidene-2-norbornene, ( Examples include (meth) acrylic acid esters such as methyl (meth) acrylate and ethyl (meth) acrylate, and other (meth) acrylic acid derivatives such as (meth) acrylonitrile and (meth) acrylamide. These monomers may be used individually by 1 type, and may be used in combination of 2 or more type. The copolymerization mode is not particularly limited, and may be, for example, a block copolymer, a graft copolymer, or a random copolymer.

  Specific examples of the conjugated diene polymer include natural rubber (NR), styrene-isoprene rubber (SIR), styrene-butadiene rubber (SBR), polyisoprene rubber (IR), polybutadiene rubber (BR), isoprene-isobutylene copolymer Examples thereof include a combined rubber (IIR), an ethylene-propylene-diene copolymer rubber (EPDM), a butadiene-isoprene copolymer rubber (BIR), a styrene-isoprene block polymer, and a styrene-butadiene block polymer. Among these, polyisoprene rubber, polybutadiene rubber, and styrene-isoprene block polymer are preferably used, polyisoprene rubber and styrene-isoprene block polymer are more preferably used, and polyisoprene rubber is most preferably used. These conjugated diene polymers may be used individually by 1 type, and may be used in combination of 2 or more type.

  The content of the conjugated diene monomer unit in the conjugated diene polymer is not particularly limited, but is usually 40 mol% or more, preferably 60 mol% or more, more preferably 80 mol% or more. The production method of the conjugated diene polymer may be in accordance with a conventional method. For example, using a suitable catalyst such as a Ziegler polymerization catalyst, an alkyl lithium polymerization catalyst, a radical polymerization catalyst, etc. By polymerizing the monomer, a conjugated diene polymer can be obtained. A conjugated diene polymer obtained by polymerization with a Ziegler polymerization catalyst and then metathesis decomposition using a catalyst such as ruthenium or tungsten can also be used.

  Further, the microstructure of the conjugated diene monomer unit in the conjugated diene polymer is not particularly limited, and the cis-1,4 structure, trans-1,4 structure, vinyl-1,2 structure and vinyl-3,4 structure are not limited. Each may be present in any proportion.

  The conjugated diene polymer cyclized product can be obtained by cyclizing the conjugated diene polymer as described above in the presence of an acid catalyst. Known acid catalysts can be used for the cyclization reaction. Specific examples thereof include sulfuric acid; fluoromethanesulfonic acid, difluoromethanesulfonic acid, p-toluenesulfonic acid, xylenesulfonic acid, alkylbenzenesulfonic acid having an alkyl group having 2 to 18 carbon atoms, anhydrides and alkyl esters thereof, and the like. Organic sulfonic acid compounds: boron trifluoride, boron trichloride, tin tetrachloride, titanium tetrachloride, aluminum chloride, diethylaluminum monochloride, ethylammonium chloride, aluminum bromide, antimony pentachloride, tungsten hexachloride, iron chloride, etc. A Lewis acid. These acid catalysts may be used alone or in combination of two or more. Moreover, you may use together a tertiary butyl chloride and a trichloroacetic acid as a promoter. Among these, an organic sulfonic acid compound is preferably used, and p-toluenesulfonic acid and xylenesulfonic acid are more preferably used. The usage-amount of an acid catalyst is 0.05-10 weight part normally per 100 weight part of conjugated diene polymers, Preferably it is 0.1-5 weight part, More preferably, it is 0.3-2 weight part.

  The cyclization reaction is usually performed by dissolving the conjugated diene polymer in a solvent. The solvent is not particularly limited as long as it does not inhibit the cyclization reaction, but is an aromatic hydrocarbon such as benzene, toluene, xylene, ethylbenzene; n-pentane, n-hexane, n-heptane, n-octane, etc. Hydrocarbon solvents such as aliphatic hydrocarbons; alicyclic hydrocarbons such as cyclopentane and cyclohexane; are preferably used. The boiling point of these solvents is preferably 70 ° C. or higher. The solvent used for the polymerization reaction of the conjugated diene polymer and the solvent used for the cyclization reaction may be of the same type. In this case, an acid catalyst for cyclization reaction can be added to the polymerization reaction solution after completion of the polymerization reaction, and the cyclization reaction can be carried out following the polymerization reaction. The amount of the solvent used is such that the solid content concentration of the conjugated diene polymer is usually 5 to 60% by weight, preferably 20 to 40% by weight.

  The cyclization reaction can be carried out under any pressure of pressure, reduced pressure and atmospheric pressure, but it is desirable to carry out under atmospheric pressure from the viewpoint of easy operation. When the cyclization reaction is performed in a dry air flow, particularly in an atmosphere of dry nitrogen or dry argon, side reactions caused by moisture can be suppressed. The reaction temperature and reaction time in the cyclization reaction are not particularly limited. The reaction temperature is usually 50 to 150 ° C., preferably 70 to 110 ° C., and the reaction time is usually 0.5 to 15 hours, preferably 2 to 10 hours. After carrying out the cyclization reaction, the acid catalyst is deactivated and the acid catalyst residue is removed by a conventional method, and then the solvent is removed to obtain a solid conjugated diene polymer cyclized product.

  The unsaturated bond reduction rate of the conjugated diene polymer cyclized product used as the oxygen-absorbing resin is not particularly limited, but is preferably 45% or more, more preferably 50 to 80%, 55 It is particularly preferred to be ˜75%. By using a conjugated diene polymer cyclized product having an unsaturated bond reduction rate in such a range, it is possible to satisfactorily suppress the generation of odor accompanying oxygen absorption of the oxygen-absorbing resin composition. In addition, as the conjugated diene polymer cyclized product, two or more conjugated diene polymer cyclized products having different unsaturated bond reduction rates may be used in combination.

  The unsaturated bond reduction rate of the conjugated diene polymer cyclized product is an index representing the degree to which the unsaturated bond is reduced by the cyclization reaction in the conjugated diene monomer unit portion in the conjugated diene polymer. It is a numerical value obtained by That is, by proton NMR analysis, in the conjugated diene monomer unit portion in the conjugated diene polymer, the ratio of the peak area of the proton directly bonded to the double bond to the peak area of all protons is measured before and after the cyclization reaction, respectively. Calculate the reduction rate. Specifically, the unsaturated bond reduction rate of the conjugated diene polymer cyclized product can be determined as described below. That is, in the conjugated diene monomer unit portion in the conjugated diene polymer, the total proton peak area before the cyclization reaction is SBT, the peak area of the proton directly bonded to the double bond is SBU, and the total proton after the cyclization reaction Assuming that the peak area is SAT and the peak area of the proton directly bonded to the double bond is SAU, the peak area ratio (SB) of the proton directly bonded to the double bond before the cyclization reaction is expressed by the formula: SB = SBU / SBT The peak area ratio (SA) of protons directly bonded to the double bond after the cyclization reaction is represented by the formula: SA = SAU / SAT. The unsaturated bond reduction rate is obtained by the formula: unsaturated bond reduction rate (%) = 100 × (SB−SA) / SB.

  The unsaturated bond reduction rate of the conjugated diene polymer cyclized product can be adjusted by appropriately selecting the amount of acid catalyst, reaction temperature, reaction time, etc. in the cyclization reaction of the conjugated diene polymer.

  The weight average molecular weight of the conjugated diene polymer cyclized product is usually 1000 to 1,000,000, preferably 50,000 to 500,000, more preferably as a standard polystyrene conversion value measured by gel permeation chromatography. 80,000-300,000. The weight average molecular weight of the conjugated diene polymer cyclized product can be adjusted by appropriately selecting the weight average molecular weight of the conjugated diene polymer subjected to the cyclization reaction. In addition, when the conjugated diene polymer cyclized product is a conjugated diene / aromatic vinyl monomer copolymer cyclized product, the weight average molecular weight of the aromatic vinyl polymer block may be 1000 to 300,000. preferable. By appropriately setting the weight average molecular weight of the conjugated diene polymer cyclized product, the solution viscosity at the time of the cyclization reaction becomes appropriate, and the workability and mechanical strength of the obtained oxygen-absorbing resin composition are improved. It becomes good.

  The content of the gel in the conjugated diene polymer cyclized product is usually 10% by weight or less, preferably 5% by weight or less, and particularly preferably substantially free of gel, as the content of toluene insolubles. . When there is much content of gel, the workability of the oxygen-absorbing resin composition obtained may worsen.

  The glass transition temperature of the conjugated diene polymer cyclized product is not particularly limited, but is usually 0 ° C or higher, preferably 20 ° C or higher, and more preferably 40 to 80 ° C. The glass transition temperature of the conjugated diene polymer cyclized product is to adjust the reduction rate of unsaturated bond of the conjugated diene polymer cyclized product according to the type of conjugated diene polymer used to obtain the conjugated diene polymer cyclized product. It can be adjusted by.

  In the oxygen-absorbing resin composition of the present invention, it is preferable to use a conjugated diene polymer cyclized product mixed with a fatty acid. By adding a fatty acid to the conjugated diene polymer cyclized product, the oxygen absorption of the conjugated diene polymer cyclized product can be improved. Although the fatty acid mix | blended with a conjugated diene polymer cyclization thing is not specifically limited, A C18-44 higher unsaturated fatty acid or a higher saturated fatty acid is suitable. Specific examples of higher unsaturated fatty acids having 18 to 44 carbon atoms include linear unsaturated fatty acids such as oleic acid, eicosenoic acid, erucic acid, 2-methyl-9-octadecenoic acid, 2-methyl-2-eicosenoic acid, etc. Multimers of unsaturated fatty acids such as branched unsaturated fatty acids and dimer acids. Specific examples of higher saturated fatty acids having 18 to 44 carbon atoms include linear saturated fatty acids such as stearic acid, arachidic acid, behenic acid and lignoceric acid, isostearic acid, isoarachidic acid, isobehenic acid and isolignoceric acid. Examples thereof include hydrogenated products of multimers of unsaturated fatty acids such as branched saturated fatty acids and dimer acid hydrogenated products. Among these, hydrogenated products of erucic acid or dimer acid are preferably used. These fatty acids may be used alone or in combination of two or more. Although the compounding quantity of a fatty acid is not specifically limited, It is 20 weight% or less normally with respect to the weight of a conjugated diene polymer cyclization thing, Preferably it is 0.1-10 weight%.

  In the oxygen-absorbing resin composition of the present invention, a softening agent may be blended with the conjugated diene polymer cyclized product. By blending a softening agent into the conjugated diene polymer cyclized product, the minimum temperature at which the conjugated diene polymer cyclized product can sufficiently exhibit the oxygen absorbing ability can be adjusted. As the softening agent, a liquid material having a glass transition temperature of −30 ° C. or less is preferably used. Specific examples thereof include hydrocarbon oils such as isoparaffinic oil, naphthenic oil, liquid paraffin, polybutene, Olefin polymers (low molecular weight) such as polyisobutylene, atactic polypropylene, ethylene-α-olefin copolymers (linear low density polyethylene (LLDPE), linear ultra-low density polyethylene (LVLDPE), etc.); polyisoprene And hydrides (low molecular weight) of conjugated diene polymers such as butadiene and polybutadiene; hydrides (low molecular weight) of styrene-conjugated diene polymers. These softeners may be used alone or in combination of two or more. The blending amount of the softening agent is not particularly limited, but is usually 15% by weight or less, preferably 5% by weight or less based on the weight of the conjugated diene polymer cyclized product.

  A transition metal catalyst can be added to the conjugated diene polymer cyclized product (oxygen-absorbing resin) used in the present invention for the purpose of exerting its oxygen-absorbing ability or improving its oxygen-absorbing ability. As the transition metal catalyst, a known transition metal compound can be used as an oxidation catalyst. For example, salts of transition metals such as manganese, iron, cobalt, nickel, copper, rhodium, and ruthenium can be given as typical examples. Can do. Examples of transition metal salt forms include chloride, acetate, stearate, palmitate, ethyl 2-ethylhexanoate, neodecanoate, and naphthoate. However, in the present invention, it is preferable to use a conjugated diene polymer cyclized product that does not substantially contain a transition metal catalyst from the viewpoint of suppressing the generation of odor accompanying oxygen absorption.

The oxygen absorption rate of the oxygen-absorbing resin used in the present invention is not particularly limited, but the oxygen absorption rate at 30 ° C. is preferably 0.01 cc / 100 cm ² · day or more. Here, the oxygen absorption rate of the oxygen-absorbing resin is such that the target oxygen-absorbing resin is a film having a thickness of 20 μm, and the film is placed in a constant volume of dry air at 30 ° C. and atmospheric pressure. In addition, the oxygen capacity (unit: cc) that the film absorbs per unit area (100 cm ² ) per day (24 hours) shall be expressed.

  The base resin that is a component of the oxygen-absorbing resin composition of the present invention is at least one thermoplastic resin selected from polyolefins and aliphatic polyamides. The polyolefin that can be used as the base resin is a thermoplastic resin having an olefin as a main repeating unit, and is a homopolymer of α-olefin, a copolymer of two or more α-olefins, and α-olefin and α-olefin. Any of copolymers with monomers other than olefins may be used, and these (co) polymers may be modified. Specific examples of polyolefins include homopolymers or copolymers of α-olefins such as ethylene and propylene, such as linear low density polyethylene (LLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), Α-olefin homopolymers such as high density polyethylene (HDPE), polyethylene such as metallocene polyethylene, polypropylene, metallocene polypropylene, polymethylpentene, polybutene; copolymers of ethylene and other α-olefins such as ethylene-propylene Random copolymer, ethylene-propylene block copolymer, ethylene-butene-1 copolymer, ethylene-propylene-butene-1 copolymer, and ethylene-cyclic olefin copolymer; α-olefin as a main component, α -Olefin and potassium Copolymers with sulphonic acid unsaturated alcohols and saponified products thereof, for example, ethylene-vinyl acetate copolymers, ethylene-vinyl alcohol copolymers; α-olefins mainly composed of α-olefins and α, β-unsaturated Copolymer with saturated carboxylic acid ester or α, β-unsaturated carboxylic acid, for example, ethylene-α, β-unsaturated carboxylic acid ester copolymer (ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid) Methyl copolymers, etc.), ethylene-α, β-unsaturated carboxylic acid copolymers (ethylene-acrylic acid copolymers, ethylene-methacrylic acid copolymers, etc.); α-olefins (co) such as polyethylene and polypropylene The polymer may be unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid and / or An acid-modified olefin resin modified with the anhydride; an ionomer resin in which Na ion or Zn ion is allowed to act on a copolymer of ethylene and methacrylic acid; and a mixture thereof.

  The aliphatic polyamide that can be used as the base resin is an aliphatic polyamide that is a thermoplastic resin that does not substantially contain an aromatic ring structure in its molecular structure. Specific examples of the aliphatic polyamide include polyamide 6, polyamide 66, polyamide 6/66, polyamide 6/10, polyamide 11 and polyamide 12. In addition, the at least 1 thermoplastic resin selected from polyolefin and aliphatic polyamide may be used individually by 1 type, and may use 2 or more types together.

  The mixing ratio of the oxygen-absorbing resin and the base resin in the oxygen-absorbing resin composition is not particularly limited, but the weight ratio of the oxygen-absorbing resin / base resin is preferably 20/80 to 50/50. 25/75 to 45/55 is more preferable. When the weight ratio of oxygen-absorbing resin / base resin is within this range, the balance between oxygen-absorbing property and moldability of the obtained oxygen-absorbing resin composition is particularly good.

  As described later, the oxygen-absorbing resin composition of the present invention has been described above as long as the content of calcium stearate in the oxygen-absorbing resin composition is not more than a specific value as the calcium element content derived from calcium stearate. You may mix | blend other components other than a thing. Specific examples of components other than resins that can be blended include antioxidants; lubricants; heat stabilizers; compatibilizers; ultraviolet absorbers; colorants; pigments; neutralizers; plasticizers such as phthalates and glycol esters Fillers such as alumina and titanium oxide; tackifiers; surfactants; leveling agents; UV absorbers; light stabilizers; dehydrating agents; pot life extenders (acetylacetone, methanol, methyl orthoacetate, etc.); Agents;

  In the oxygen-absorbing resin composition of the present invention, the content of calcium stearate needs to be 5 μg / g or less as the calcium element content derived from calcium stearate, and preferably 3 μg / g or less. More preferably, it is 2 μg / g or less. In the oxygen-absorbing resin composition of the present invention, when the calcium stearate content is a specific amount or less, inhibition of oxygen absorption of the oxygen-absorbing resin by calcium stearate is suppressed, and as a result, it has excellent oxygen absorbability. It will be a thing. In the present invention, the calcium element content derived from calcium stearate is measured by inductively coupled plasma emission spectroscopy (ICP-AES method).

  The method of setting the calcium element content derived from calcium stearate in the oxygen-absorbing resin composition of the present invention to a specific value or less is not particularly limited, but for each component for constituting the oxygen-absorbing resin composition, the steer A method of selecting a calcium phosphate that is substantially free of calcium phosphate or has a very low concentration even if it is included is simple. When this method is followed, many commercially available thermoplastic resins contain calcium stearate as a lubricant, so select an oxygen-absorbing resin or base resin that is substantially free of calcium stearate. It is particularly important to do.

  The oxygen-absorbing resin composition of the present invention may contain an antioxidant. However, if there is too much content of antioxidant, there is a possibility that oxygen absorption of the oxygen-absorbing resin may be inhibited, so that the antioxidant content in the oxygen-absorbing resin composition is 200 μg / g or less. Is more preferably 150 μg / g or less, and particularly preferably 100 μg / g or less. In addition, in this invention, antioxidant content shall be measured by a high performance liquid chromatography (HPLC) in principle.

  The type of the antioxidant is not particularly limited as long as it is normally used in the field of resin materials and rubber materials. Typical examples of such antioxidants include hindered phenol-based, phosphorus-based and lactone-based antioxidants. These antioxidants can also be used in combination of two or more. Among these, it is preferable to use a phosphorus-based antioxidant. In addition to these antioxidants, an amine light stabilizer (HALS) may be further added.

  In obtaining the oxygen-absorbing resin composition, the method for mixing the oxygen-absorbing resin, the base resin, and other components added as necessary is not particularly limited, and a known method may be adopted. From the viewpoint of simplicity and cost, a melt-kneading method is preferably used.

  The apparatus used when the melt-kneading method is adopted when obtaining the oxygen-absorbing resin composition is not particularly limited. For example, a continuous intensive mixer, a kneading type twin-screw extruder (same direction or different direction), Continuous type kneaders such as mixing rolls and kneaders; Batch type kneaders such as high-speed mixers, Banbury mixers, intensive mixers, pressure kneaders, etc .; An apparatus using a rotating disk; a single-screw extruder provided with a kneading part (Dalmage, CTM, etc.); and a simple kneader such as a ribbon blender or a Brabender mixer. The kneading temperature is not particularly limited, but is preferably 160 to 260 ° C, and more preferably 180 to 240 ° C.

  The oxygen-absorbing resin composition of the present invention obtained as described above can be suitably used for various applications as an oxygen-absorbing material. Among them, contents such as foods, beverages, and pharmaceuticals can be used. It is particularly suitably used as a packaging material for packaging.

  When the packaging material is constituted using the oxygen-absorbing resin composition of the present invention, the form is not particularly limited, for example, a form serving as a material for packaging materials such as a film, a sheet, a parison, a preform, a tube, It can be in the form of packaging materials such as bottles, cups, bags, and trays.

  What is necessary is just to shape | mold into the shape of a film according to the shaping | molding method of a well-known resin film, when making the oxygen absorptive resin composition of this invention into a film form. For example, after dissolving the oxygen-absorbing resin composition of the present invention in a solvent, a film can be obtained by a solution casting method in which a solution is applied and dried on a substantially flat surface. Also, for example, the oxygen-absorbing resin composition of the present invention is melt-kneaded with an extruder and then extruded into a predetermined shape through a T-die, a circular die (ring die), etc. Film etc. are obtained. As the extruder, a kneader such as a single screw extruder, a twin screw extruder, or a Banbury mixer can be used. When the oxygen-absorbing resin composition of the present invention is formed into a film, the film may be stretched or stretched in one or more directions.

  The form of the film when the oxygen-absorbing resin composition of the present invention is made into a film is not particularly limited, and may be, for example, a monolayer consisting only of the oxygen-absorbing resin composition of the present invention, The layer formed by laminating other layers on the layer composed of the oxygen-absorbing resin composition of the present invention as an oxygen-absorbing layer may be used. However, when another layer made of a thermoplastic resin is laminated adjacent to the layer of the oxygen-absorbing resin composition of the present invention, if the layer to be laminated contains calcium stearate in a specific amount or more, oxygen There exists a possibility that the oxygen absorption of an absorptive resin composition may be inhibited. Therefore, it is preferable that the calcium stearate content of the other layer made of the thermoplastic resin laminated adjacent to the layer of the oxygen-absorbing resin composition of the present invention is not more than a specific amount. That is, the oxygen-absorbing laminate of the present invention has an oxygen-absorbing layer made of the oxygen-absorbing resin composition of the present invention and an adjacent resin layer made of a thermoplastic resin laminated on the oxygen-absorbing layer. In the oxygen-absorbing laminate, the content of calcium stearate in the adjacent resin layer is 20 μg / g or less as the content of calcium element derived from calcium stearate. In the present invention, the “adjacent resin layer” is a layer made of a thermoplastic resin, and is a layer laminated so as to be in direct contact with the oxygen-absorbing layer made of the oxygen-absorbing resin composition of the present invention or the present invention. Means a layer laminated on an oxygen-absorbing layer comprising the oxygen-absorbing resin composition only through a layer (adhesive layer described later) that functions to improve adhesion between the oxygen-absorbing layer and the adjacent resin layer. Shall.

  In the oxygen-absorbing laminate of the present invention, the content of calcium stearate in the adjacent resin layer needs to be 20 μg / g or less as the calcium element content derived from calcium stearate, and 10 μg / g. g or less is preferable, and 5 μg / g or less is more preferable. In the oxygen-absorbing laminate of the present invention, the oxygen absorption of the oxygen-absorbing layer comprising the oxygen-absorbing resin composition of the present invention is inhibited by the content of calcium stearate in the adjacent resin layer being a specific amount or less. As a result, it has excellent oxygen absorption.

  The adjacent resin layer may contain an antioxidant, but if the content of the antioxidant in the adjacent resin layer is too large, the oxygen absorption of the oxygen-absorbing layer may be inhibited. Therefore, the antioxidant content of the adjacent resin layer is preferably 500 μg / g or less, more preferably 300 μg / g or less, and particularly preferably 100 μg / g or less. In addition, as an antioxidant which can be added to an adjacent resin layer, the same thing as what was illustrated as an antioxidant which can be added to an oxygen absorptive resin composition can be mentioned.

  In the oxygen-absorbing laminate of the present invention, the function performed by the adjacent resin layer is not particularly limited as long as the thermoplastic resin to be used can perform, and the adjacent resin layer includes, for example, a sealing material layer, a protective layer, and an oxygen barrier. It can function as a layer. Moreover, what is necessary is just to determine the kind of thermoplastic resin which comprises an adjacent resin layer according to the function made into the objective.

  The sealing material layer is a layer having a function of forming a space that is cut off from the outside of the packaging container in the packaging container constituted by the oxygen-absorbing laminate by being melted by heat and bonded to each other (heat sealed) It is. Examples of the material used for forming the sealing material layer include a thermoplastic resin that can be easily heat-sealed, and specific examples thereof include homopolymers of ethylene and homopolymers of α-olefins such as propylene, for example, , Low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, metallocene polyethylene, polypropylene, polymethylpentene, polybutene; copolymers of ethylene and α-olefins, for example, ethylene-propylene copolymers; Copolymers mainly composed of α-olefin, such as α-olefin and vinyl acetate, acrylic acid ester, methacrylic acid ester, such as ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene- Methyl methacrylate copolymer, ethylene-acrylic acid Polymers, poly-α-olefin resins such as ethylene-methacrylic acid copolymers; α-olefin (co) polymers such as polyethylene and polypropylene, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid Acid-modified poly α-olefin resin modified with an unsaturated carboxylic acid such as; an ionomer resin in which Na ion or Zn ion is allowed to act on a copolymer of ethylene and methacrylic acid; and a mixture thereof.

  The protective layer is a layer mainly provided in the outermost layer of the oxygen-absorbing laminate for the purpose of imparting heat resistance and printability to the oxygen-absorbing laminate. Examples of the thermoplastic resin used for the protective layer include ethylene polymers such as high-density polyethylene; propylene polymers such as propylene homopolymer, propylene-ethylene random copolymer, propylene-ethylene block copolymer; polyamide 6, polyamide 66 Polyamides such as copolyamide 6/66, polycaproamide, polyhexamethylene adipamide, polymetaxylylene adipamide; polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate; polyvinylidene chloride; polyvinyl chloride Polystyrene, polyacrylonitrile, polycarbonate, polyacrylate, polyketone, and the like.

  The oxygen barrier layer is mainly on the outside of the oxygen-absorbing layer for the purpose of reducing the amount of oxygen entering the oxygen-absorbing layer and the inside of the packaging container from the outside of the packaging container composed of the oxygen-absorbing laminate. It is a layer to be provided. Examples of the thermoplastic resin that can be used when the oxygen barrier layer is made of a thermoplastic resin include polyvinyl alcohol resins such as polyvinyl alcohol and ethylene-vinyl alcohol copolymers, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyamide 6 , Polyamide 66, polyamide 610, polyamide 11, polyamide 12, polyamide MXD6, copolymer polyamide 6/66 and other polyamide resins, polyaramid resins, polycarbonate resins, polystyrene resins, polyacetal resins, fluororesins, polyethers, adipate esters, Caprolactone ester-based, polycarbonate-based thermoplastic polyurethane, polyvinylidene chloride, polyvinyl chloride and other halogenated vinyl resins, polyacrylonitrile , Ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, etc. An acid-modified polyolefin resin obtained by modifying polyethylene or α-olefin (co) polymer with an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid or itaconic acid; a copolymer of ethylene and methacrylic acid Examples thereof include ionomer resins in which Na ions and Zn ions are allowed to act on polymers, and mixtures thereof.

  To the thermoplastic resin constituting the adjacent resin layer, an ultraviolet absorber; a colorant; a pigment; a neutralizer; a filler such as calcium carbonate, alumina, titanium oxide; a tackifier; Surfactant; leveling agent; ultraviolet absorber; light stabilizer; dehydrating agent; pot life extending agent (acetylacetone, methanol, methyl orthoacetate, etc.); repellent improver;

  In the oxygen-absorbing laminate of the present invention, the thickness of the oxygen-absorbing layer is not particularly limited and may be set according to the required amount of oxygen absorption, but is usually 5 to 100 μm, preferably 10 to 10 μm. It is set within a range of 30 μm. Further, the thickness of the adjacent resin layer may be set according to the intended function and the like, and is not particularly limited, but is usually set in the range of 20 to 80 μm, preferably 30 to 70 μm.

  Even if the oxygen-absorbing laminate of the present invention is a two-layer body in which the adjacent resin layer is laminated on one side of the oxygen-absorbing layer, the three layers in which the adjacent resin layer is laminated on both sides of the oxygen-absorbing layer It may be a body, or a multilayer body in which another layer is further laminated thereon. Moreover, you may interpose the layer which fulfill | performs the adhesive improvement function of these two layers, ie, an adhesive bond layer, between arbitrary layers.

  The material of the adhesive layer may be determined according to the material of the two layers that need to improve adhesion, and is not particularly limited. For example, polyolefin such as polyethylene and polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylic Acid copolymers, ethylene-ethyl acrylate copolymers, ethylene-methacrylic acid copolymers, ethylene-methyl methacrylate copolymers, and these polymers include unsaturated carboxylic acids such as maleic anhydride and the like Those modified with an anhydride (addition, grafting, etc.) may be mentioned. Among these, a polymer modified with an unsaturated carboxylic acid or an anhydride thereof is preferably used, and a polyolefin modified with an unsaturated carboxylic acid or an anhydride thereof is particularly preferably used. Although the thickness of an adhesive bond layer is not specifically limited, Usually, it sets in the range of 2-10 micrometers.

  The method for producing the oxygen-absorbing laminate of the present invention is not particularly limited, and each layer constituting the laminate may be obtained as a single layer film, which may be laminated, or the laminate may be directly formed. As a method for directly forming an oxygen-absorbing laminate, a known co-extrusion method can be used, for example, extrusion using a number of extruders and multilayer multiple dies according to the type of material constituting each layer. Should be done. Specific examples of the coextrusion molding method include a coextrusion lamination method, a coextrusion sheet molding method, a coextrusion inflation molding method, a coextrusion cast molding method, and a coextrusion blow molding method.

  When the oxygen-absorbing laminate is produced by a coextrusion molding method, the temperature of the material constituting each layer is preferably molded as 160 to 260 ° C, more preferably 180 to 240 ° C. If the molding temperature is too low, the laminate may be uneven in thickness or cut. If the molding temperature is too high, the laminate may be cut. The film winding speed during production of the laminate is not particularly limited, but is usually 10 to 200 m / min, preferably 20 to 100 m / min. If the winding speed is too low, the production efficiency may be deteriorated. If the winding speed is too high, the laminate cannot be cooled sufficiently, and may be fused at the time of winding.

  Another layer may be further laminated on the laminate obtained by the coextrusion molding method to obtain the target oxygen-absorbing laminate. In particular, when an oxygen barrier layer using an inorganic material such as a metal or metal oxide having a higher oxygen barrier property is laminated as an oxygen barrier layer, a dry laminate method, a wet laminate method, a non-solvent lamination method, etc. It is preferable to laminate an oxygen barrier layer on a laminate including an oxygen-absorbing layer and an adjacent resin layer using a lamination method. As an example of the oxygen barrier layer to be laminated in this way, a resin film in which a metal foil such as aluminum or a metal oxide such as silica or alumina is deposited can be given. The metal oxide vapor-deposited film may be provided with an overcoat layer formed of, for example, a polyvinyl alcohol / silane compound-based material for the purpose of further improving the oxygen barrier property, or vapor-deposited with other films. A primer layer may be provided in order to improve the adhesion with the film.

  The total thickness of the oxygen-absorbing laminate of the present invention is not particularly limited, but is usually less than 800 μm, preferably 50 to 400 μm.

  The oxygen-absorbing laminate of the present invention may be subjected to post-processing such as embossing as necessary. The oxygen-absorbing laminate can be used in various forms of packaging containers and packaging materials, such as pouches (bags), boxes, cups, etc., packaging films, lids It can be used as a packaging material.

  The oxygen-absorbing laminate of the present invention is preferably used as a packaging material for packaging contents that deteriorate due to oxygen. Examples of contents that deteriorate due to oxygen include seasonings, sauces, soy sauce, dressings, liquid soup, seasonings such as mayonnaise, miso, grated spices, pasty foods such as jam, cream, chocolate paste, liquid soup, Liquid foods typified by liquid processed foods such as boiled foods, pickles and stews, raw noodles such as buckwheat noodles, udon and ramen, boiled noodles, polished rice, conditioned rice, and unwashed rice Processed rice products such as cooked rice, gomoku rice, red rice, rice bran, high-moisture foods such as powdered soup, powdered seasonings such as dashi-no-moto, dried vegetables, coffee beans, coffee powder, tea, grains Low-moisture foods such as confectionery, other solid and solution chemicals such as pesticides and insecticides, liquid and paste pharmaceuticals, lotions, cosmetic creams, and milk , Hair dressing, mention may be made of hair dye, shampoo, soap, detergent and the like. The oxygen-absorbing laminate of the present invention can also be suitably used as a packaging material to which heat sterilization treatment such as retort treatment and boil treatment is applied. Examples of contents to which heat sterilization such as retort processing and boil processing are applied include curry, soup, stew, rice cake, pasta sauce, rice bowl ingredients, hamburger, meatballs, food such as nursing food and infusions, etc. Can be mentioned.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. In addition, unless otherwise indicated, the part and% in each example are a basis of weight.

  Various measurements were performed according to the following methods.

[Weight average molecular weight (Mw) of cyclized conjugated diene polymer]
It calculated | required as polystyrene conversion molecular weight using the gel permeation chromatography. Tetrahydrofuran was used as an elution solvent.

[Reduction rate of unsaturated bond of cyclized conjugated diene polymer]
(I) M.M. A. Golub and J.M. Heller, Can. J. et al. Chem. 41, 937 (1963). And (ii) Y. Tanaka and H.M. Sato, J .; Polym. Sci: Poly. Chem. Ed. 17, 3027 (1979). It was determined by proton NMR measurement with reference to the method described in the literature. In the conjugated diene monomer unit portion in the conjugated diene polymer, the total proton peak area before the cyclization reaction is SBT, the peak area of the proton directly bonded to the double bond is SBU, and the total proton after the cyclization reaction Assuming that the peak area is SAT and the peak area of the proton directly bonded to the double bond is SAU, the peak area ratio (SB) of the proton directly bonded to the double bond before the cyclization reaction is expressed by the formula: SB = SBU / SBT The peak area ratio (SA) of protons directly bonded to the double bond after the cyclization reaction is represented by the formula: SA = SAU / SAT. Therefore, the unsaturated bond reduction rate is obtained by the formula: unsaturated bond reduction rate (%) = 100 × (SB−SA) / SB.

〔Glass-transition temperature〕
Using a differential scanning calorimeter (“EXSTAR 6000 DSC” manufactured by Seiko Instruments Inc.), the measurement was performed in a nitrogen stream at a heating rate of 10 ° C./min.

[Calcium element content]
About 0.6 g of a sample (pellet for the oxygen-absorbing resin composition, cut out from the molded film for the sealing material layer) is taken in a volumetric flask, and this is subjected to wet decomposition with nitric acid, and then made up to 7 mL with ultrapure water. A sample solution was prepared by measuring up, and an inductively coupled plasma emission spectroscopy was applied thereto, and the calcium element content (unit: μg / g) was calculated from the spectral intensity at a wavelength of 396.847 nm. The measurement conditions of inductively coupled plasma emission spectrometry were as follows, and the calibration curve was prepared with a mixed standard solution for ICP-AES (“XSTC-22” manufactured by Nishishin Shoji Co., Ltd.).
Analyzer: “SPS5100” manufactured by SII Nano Technology
Carrier gas: Argon gas nebulizer flow rate: 0.75 L / min Plasma flow rate: 15.0 L / min Auxiliary flow rate: 1.5 L / min

[Antioxidant content]
About 1.3 g of a sample (pellet for the oxygen-absorbing resin composition, and cut out from the molded film for the sealing material layer) was extracted with a Soxhlet extractor using diethyl ether as an extraction solvent. Next, after the extract was concentrated, 200 μL of toluene was added to adjust the whole, and the volume was made up to 5 mL with acetonitrile. The solution was subjected to ultrasonic irradiation for 30 seconds, filtered through a disk filter having a pore size of 0.2 μm, and analyzed by high performance liquid chromatography using the filtrate as a sample. (Unit: μg / g) was calculated. The measurement conditions for high performance liquid chromatography are as follows.
Analyzer: Agilent Technologies "Agilent 1200 Series"
Column: “ZORBAX XDB-C8” manufactured by Agilent Technologies
Column temperature: 40 ° C
Solvent: acetonitrile: water = 70: 30 (0-3 minutes), acetonitrile: water = 92: 8 (3 minutes-)
Flow rate: 0.75 mL / min

[Oxygen absorption]
After completely expelling the air in the pouch as a sample, 100 mL of water, 10 mL of air, and a nondestructive oxygen concentration glass sensor (“Oxygen sensor PSt3” manufactured by PreSens) were enclosed in the pouch. Subsequently, this pouch was retorted at 121 ° C. for 30 minutes using a steam heating retort treatment device (“Retort High Pressure Steam Sterilizer RK-3030” manufactured by Alp). And about the pouch immediately after a retort process, the oxygen concentration in a pouch was measured using the nondestructive oxygen concentration meter ("Fibox3" by PreSens). The lower the oxygen concentration, the better the oxygen absorption.

[Production example]
Polyisoprene (cis-1,4 units 73%, trans-1,4 units 22%, 3,4) cut into 10 mm square in a pressure-resistant reactor equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube -Unit 5%, weight average molecular weight 243,100) 100 parts were charged together with 374 parts cyclohexane. After purging the inside of the reactor with nitrogen, the mixture was heated to 75 ° C. and the polyisoprene was completely dissolved in cyclohexane with stirring, and then p-toluenesulfonic acid (in toluene, so that the water content was 150 ppm or less, The cyclization reaction was carried out while adding 0.90 parts of a 15% toluene solution and controlling the temperature not to exceed 80 ° C. After reacting for 7 hours, 25% aqueous sodium carbonate solution containing 0.59 parts of sodium carbonate was added to stop the reaction. After removing water by azeotropic reflux dehydration at 80 ° C., the catalyst residue in the system was removed with a glass fiber filter having a pore size of 2 μm. Cyclohexane was distilled off from the resulting solution, and further toluene was removed by vacuum drying to obtain a solid conjugated diene polymer cyclized product. The conjugated diene polymer cyclized product had a weight average molecular weight of 189,100, an unsaturated bond reduction rate of 62.6%, and a glass transition temperature of 56 ° C.

The obtained solid conjugated diene polymer cyclized product was obtained by using a single-screw kneading extruder (40φ, L / D = 25, die diameter 3 mm × 1 hole, manufactured by Ikekai Co., Ltd.), cylinder 1: 140 ° C., cylinder 2: 150 ° C., cylinder 3: 160 ° C., cylinder 4: 170 ° C., die temperature: 170 ° C., kneading conditions of 25 rpm, and pelletized.
[Example 1]
26.5 parts of conjugated diene polymer cyclized pellets obtained in Production Example, a small amount of hindered phenolic antioxidant (pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) Propionate]), but with no lubricant added substantially 70 parts of a random copolymer of ethylene and propylene ("Novatec PP EG7C" manufactured by Nippon Polypro Co., Ltd.) and erucic acid (manufactured by NOF Corporation) 3.5 parts using a biaxial kneader ("ZE40A" manufactured by Berstolf), cylinder 1: 180 ° C, cylinder 2: 200 ° C, cylinder 3: 200 ° C, cylinder 4: 200 ° C, die temperature 200 ° C The pellets of the oxygen-absorbing resin composition of Example 1 were obtained by kneading and pelletizing under the condition of 180 rpm. Using this pellet as a sample, the calcium element content and the antioxidant content in the oxygen-absorbing resin composition were measured. The calcium element content was 2.0 μg / g, and the antioxidant content was 42 μg / g. there were.

  Subsequently, the oxygen-absorbing resin composition obtained as described above and a small amount of a hindered phenol-based antioxidant (pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) Propionate]), but with no lubricant added, random copolymer of ethylene and propylene (“Novatech PP EG7C” manufactured by Nippon Polypro Co., Ltd .; calcium element content 2.8 μg / g, antioxidant) The content of the agent is 60 μg / g), the cylinder temperature is 230 to 250 ° C., the adapter temperature is 250 ° C., the die temperature is 250 ° C., the rotational speed is 12 rpm, the take-up speed is 1.5 m / min, Multi-layer T die-cast molding using an extrusion molding machine equipped with a die (manufactured by Soken Co., Ltd., die width 300 mm, aperture 25 mm) By performing, a film comprising two layers of an oxygen-absorbing layer composed of an oxygen-absorbing resin composition having a thickness of 20 μm and a sealing material layer (thickness of 50 μm) composed of a random copolymer of ethylene and propylene having a thickness of 50 μm. Obtained. Next, an adhesive for urethane dry lamination (“TM251 / CAT-RT88” manufactured by Toyo Morton Co., Ltd.) was applied to the oxygen-absorbing layer side of the obtained film, and a transparent silica vapor deposited film (manufactured by Mitsubishi Plastics, Inc. “ Tech barrier TXR ”) and heat seal the sealing material layer using a hot laminator (“ EXCELAM-3550 ”manufactured by GMP) while adhering each layer by a dry laminating method at a roll temperature of 90 ° C. This is a three-sided seal, and is composed of an oxygen-absorbing laminate having an oxygen barrier layer / adhesive layer / oxygen-absorbing layer / sealing material layer composed of a transparent silica vapor-deposited film from the outside and having a size of 100 mm. A pouch of Example 1 having a size of 150 mm was obtained. And when this pouch was used as a sample and this pouch was subjected to oxygen absorption evaluation, the oxygen concentration of the pouch immediately after the retort treatment was 2.6%. Composition of oxygen-absorbing resin composition in Example 1, calcium element content and antioxidant content of oxygen-absorbing resin composition, material of sealing material layer, calcium element content of sealing material layer and antioxidant The contents and the results of the oxygen absorption evaluation are summarized in Table 1.

[Example 2]
In obtaining the oxygen-absorbing resin composition, 45 parts of the conjugated diene polymer cyclized pellets obtained in the production example and a small amount of hindered phenol antioxidant (pentaerythritol tetrakis [3- (3,5-di- tert-butyl-4-hydroxyphenyl) propionate]) but with no lubricant added substantially 55 parts of a random copolymer of ethylene and propylene (“Novatech PP EG7C” manufactured by Nippon Polypro Co., Ltd.) Except for kneading, an oxygen-absorbing resin composition was obtained in the same manner as in Example 1. When the calcium element content and the antioxidant content in the oxygen-absorbing resin composition were measured, the calcium element content was 1.5 μg / g, and the antioxidant content was 33 μg / g. Subsequently, except having used this oxygen absorptive resin composition, it carried out similarly to Example 1, and obtained the pouch comprised by the oxygen absorptive laminated body. When this pouch was subjected to oxygen absorption evaluation, the oxygen concentration of the pouch immediately after the retort treatment was 4.9%. Composition of oxygen-absorbing resin composition in Example 2, calcium element content and antioxidant content of oxygen-absorbing resin composition, material of sealing material layer, calcium element content of sealing material layer and antioxidant The contents and the results of the oxygen absorption evaluation are summarized in Table 1.

Example 3
30 parts of conjugated diene polymer cyclized pellets obtained in Production Example and 70 parts of copolymerized polyamide 6/66 resin ("UBE Nylon 5034X14" manufactured by Ube Industries, Ltd.) substantially free of lubricant and antioxidant Using a twin-screw kneader ("ZE40A" manufactured by Belstolf), cylinder 1: 180 ° C, cylinder 2: 200 ° C, cylinder 3: 200 ° C, cylinder 4: 200 ° C, die temperature 200 ° C, rotation speed 150 rpm The pellets of the oxygen-absorbing resin composition of Example 3 were obtained by kneading and pelletizing under the above conditions. Using this pellet as a sample, the calcium element content and the antioxidant content in the oxygen-absorbing resin composition were measured. The calcium element content was 1 μg / g, and the antioxidant content was 0 μg / g. .

  Subsequently, the oxygen-absorbing resin composition obtained as described above, a small amount of a hindered phenol antioxidant (pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate) ], But a random copolymer of ethylene and propylene ("Novatech PP EG7C" manufactured by Nippon Polypro Co., Ltd.) and a modified polyolefin resin ("Admer QF551" manufactured by Mitsui Chemicals) ), A cylinder temperature of 190 to 215 ° C., an adapter temperature of 215 ° C., a die temperature of 215 ° C., a rotational speed of 12 rpm, a take-up speed of 1.5 m / min, and a take-up roll temperature of 40 ° C. Multi-layer T-die casting is performed by a machine (manufactured by Souken Co., Ltd., die width 300 mm, aperture 25 mm) Thus, an oxygen-absorbing layer composed of an oxygen-absorbing resin composition (thickness 20 μm) / an adhesive layer composed of a modified polyolefin resin (thickness 5 μm) / a sealing material layer composed of a random copolymer of ethylene and propylene ( A film composed of three layers having a thickness of 50 μm was obtained. Next, an urethane dry laminate adhesive (“TM251 / CAT-RT88” manufactured by Toyo Morton Co., Ltd.) was applied to the oxygen-absorbing layer side of the resulting three-layer film, and a transparent silica vapor deposited film (Mitsubishi) Resin Co., Ltd. “Tech Barrier TXR”) and a hot laminator (GMP “EXCELAM-3550”) are used, and each layer is adhered by a dry laminating method at a roll temperature of 90 ° C. The oxygen-absorbing laminate having a configuration of an oxygen barrier layer / adhesive layer / oxygen-absorbing layer / adhesive layer / sealing material layer made of a transparent silica-deposited film from the outside. Thus, a pouch of Example 3 having a size of 100 mm × 150 mm was obtained. When this pouch was subjected to oxygen absorption evaluation, the oxygen concentration of the pouch immediately after the retort treatment was 3.0%. Composition of oxygen-absorbing resin composition in Example 3, calcium element content and antioxidant content of oxygen-absorbing resin composition, material of sealing material layer, calcium element content of sealing material layer and antioxidant The contents and the results of the oxygen absorption evaluation are summarized in Table 1.

Example 4
Instead of a random copolymer of ethylene and propylene (“Novatech PP EG7C” manufactured by Nippon Polypro Co., Ltd.), a hindered phenol antioxidant (pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate]), but with substantially no lubricant added ("Prime Polypro F107" manufactured by Prime Polymer, containing calcium element) A pouch composed of an oxygen-absorbing laminate was obtained in the same manner as in Example 1 except that the amount was 1 μg / g and the antioxidant content was 420 μg / g). When this pouch was subjected to oxygen absorption evaluation, the oxygen concentration of the pouch immediately after the retort treatment was 5.4%. Composition of oxygen-absorbing resin composition in Example 4, calcium element content and antioxidant content of oxygen-absorbing resin composition, material of sealing material layer, calcium element content of sealing material layer and antioxidant The contents and the results of the oxygen absorption evaluation are summarized in Table 1.

[Comparative Example]
In obtaining an oxygen-absorbing resin composition, instead of a copolymerized polyamide 6/66 resin (“UBE Nylon 5034X14” manufactured by Ube Industries Co., Ltd.) to which an antioxidant and a lubricant are not substantially added, an antioxidant is substantially used. In the same manner as in Example 2, except that a copolymerized polyamide 6/66 resin ("UBE Nylon 5034B" manufactured by Ube Industries, Ltd.) to which calcium stearate was added as a lubricant was used. An absorbent resin composition was obtained. When the calcium element content and the antioxidant content in the oxygen-absorbing resin composition were measured, the calcium element content was 9.1 μg / g, and the antioxidant content was 0 μg / g. Next, a pouch composed of an oxygen-absorbing laminate was obtained in the same manner as in Example 2 except that this oxygen-absorbing resin composition was used. When this pouch was subjected to oxygen absorption evaluation, the oxygen concentration of the pouch immediately after the retort treatment was 14.0%. Composition of oxygen-absorbing resin composition in this comparative example, calcium element content and antioxidant content of oxygen-absorbing resin composition, material of sealing material layer, calcium element content of sealing material layer, and antioxidant content The amount and the results of the oxygen absorptivity evaluation are summarized in Table 1.

[Reference Example 1]
The oxygen-absorbing resin composition obtained in Example 1 has a cylinder temperature of 230 to 250 ° C., an adapter temperature of 250 ° C., a die temperature of 250 ° C., a rotation speed of 12 rpm, a take-up speed of 1.5 m / min, and a take-up roll temperature of 60 ° C. A single-layer film made of an oxygen-absorbing resin composition having a thickness of 20 μm is obtained by performing T-die casting with an extrusion molding machine (manufactured by Soken Co., Ltd., die width 300 mm, caliber 25 mm) provided with a T die Obtained. Next, a hindered phenolic antioxidant (pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate]) and a polypropylene with calcium stearate added as a lubricant was formed. A urethane-based dry laminate adhesive (Toyo Morton Co., Ltd.) on one side of a commercially available unstretched polypropylene film (“Pyrene Film CTP1146” manufactured by Toyobo Co., Ltd., calcium element content 43 μg / g, antioxidant content 1310 μg / g) Manufactured by "TM251 / CAT-RT88") and a transparent silica vapor-deposited film ("Tech Barrier TXR" manufactured by Mitsubishi Plastics, Inc.) coated with the same urethane-based dry laminate adhesive, Single layer comprising an oxygen-absorbing resin composition 3 layers by heat sealing the sealing material layer on the film, using a hot laminator ("EXCELAM-3550" manufactured by GMP) and bonding each layer by dry laminating method at a roll temperature of 90 ° C. Constructed from an oxygen-absorbing laminate having a structure of an oxygen barrier layer composed of a transparent silica vapor-deposited film / adhesive layer / oxygen-absorbing layer / adhesive layer / non-stretched polypropylene film. A pouch of Reference Example 1 having a size of 100 mm × 150 mm was obtained. When this pouch was subjected to oxygen absorption evaluation, the oxygen concentration of the pouch immediately after the retort treatment was 12.1%. Composition of oxygen-absorbing resin composition in Reference Example 1, content of calcium element and antioxidant in oxygen-absorbing resin composition, material of sealing material layer, content of calcium element in sealing material layer and antioxidant The contents and the results of the oxygen absorption evaluation are summarized in Table 1.

[Reference Example 2]
Instead of a random copolymer of ethylene and propylene (“Novatech PP EG7C” manufactured by Nippon Polypro Co., Ltd.), a hindered phenol antioxidant (pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate]) and polypropylene to which calcium stearate is added as a lubricant ("Prime Polypro F-300SP" manufactured by Prime Polymer Co., Ltd., calcium element content 29 μg / g) A pouch composed of an oxygen-absorbing laminate was obtained in the same manner as in Example 1 except that the antioxidant content was 610 μg / g)). When this pouch was subjected to oxygen absorption evaluation, the oxygen concentration of the pouch immediately after the retort treatment was 8.8%. Composition of oxygen-absorbing resin composition in Reference Example 2, content of calcium element and antioxidant in oxygen-absorbing resin composition, material of sealing material layer, content of calcium element in sealing material layer and antioxidant The contents and the results of the oxygen absorption evaluation are summarized in Table 1.

  As can be seen from the results shown in Table 1, the oxygen-absorbing resin composition having a low calcium element content derived from calcium stearate, like the oxygen-absorbing resin compositions of Examples 1 to 4, has excellent oxygen absorption. It can be said that it has sex. On the other hand, the oxygen-absorbing resin composition of the comparative example derived from calcium stearate and having a large calcium element content is inferior in oxygen-absorbing property as compared with the oxygen-absorbing resin compositions of Examples 1 to 4. It can be said that it is a thing. In addition, referring to Reference Examples 1 and 2, even when an oxygen-absorbing resin composition having a low calcium element content derived from calcium stearate is used as the oxygen-absorbing layer of the oxygen-absorbing laminate, it is laminated on it. When the content of calcium element derived from calcium stearate in the sealing material layer (adjacent resin layer) is large, it can be said that the excellent oxygen absorptivity of the oxygen-absorbing resin composition is not sufficiently exhibited. Therefore, when an oxygen-absorbing resin composition having a low calcium element content derived from calcium stearate is used as the oxygen-absorbing layer of the oxygen-absorbing laminate, the material of the adjacent resin layer such as a sealing material layer is also calcium stearate. It can be said that it is desirable that the derived calcium element content is small.

Claims (4)

  An oxygen-absorbing resin that is a conjugated diene polymer cyclized product and a base resin that is at least one thermoplastic resin selected from polyolefins and aliphatic polyamides, and the calcium stearate content in calcium stearate An oxygen-absorbing resin composition having a calcium element content derived from 5 μg / g or less.   The oxygen-absorbing resin composition according to claim 1, wherein the antioxidant content is 200 µg / g or less.   An oxygen-absorbing laminate comprising an oxygen-absorbing layer comprising the oxygen-absorbing resin composition according to claim 1 and an adjacent resin layer comprising a thermoplastic resin laminated on the oxygen-absorbing layer. An oxygen-absorbing laminate in which the content of calcium stearate in the adjacent resin layer is 20 μg / g or less as a calcium element content derived from calcium stearate.   The oxygen-absorbing laminate according to claim 3, wherein the antioxidant content of the adjacent resin layer is 500 μg / g or less.