JP2011136552A - Oxygen absorbing multilayered body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such problems that resin processing property is bad, applied usage is restricted and oxygen absorbing performance is inferior in the conventional oxygen absorbing resin. <P>SOLUTION: The oxygen absorbing multilayered body is made by laminating at least three layers of a sealant layer comprising a polyolefin resin, an oxygen absorbing resin layer comprising a polyolefin resin, a transition metal catalyst, an epoxy group-containing ethylene copolymer and a polyamide resin, and a gas barrier layer made of a gas barrier substance in this order, wherein the polyamide resin is a polyamide resin in which the concentration of a terminal amino group obtained by polycondensation of an aromatic diamine and a dicarboxylic acid is 30 μeq/g or less, the content of the epoxy group-containing ethylene copolymer in the oxygen absorbing resin layer is 2 to 40 wt.% per the total amount of the oxygen absorbing resin layer, and the sum content of the transition metal catalyst and the polyamide resin is 15 to 60 wt.% per the total amount of the oxygen absorbing resin layer. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an oxygen-absorbing multilayer body that exhibits excellent oxygen-absorbing performance, has no strength reduction due to oxidative degradation of the resin, has excellent resin processability, and does not generate odor.

  Conventionally, containers such as metal cans, glass bottles, and various plastic packages are known as packaging containers, but quality deterioration due to oxygen in the packaging containers is a problem. For this reason, in recent years, as one of the deoxygenation packaging technologies, a container is constituted by a multilayer material in which an oxygen absorption layer composed of an oxygen absorption resin composition in which an iron-based oxygen absorber is blended with a thermoplastic resin is provided. Development of packaging containers in which the gas barrier property is improved and the container itself is provided with an oxygen absorbing function has been performed. For example, an oxygen-absorbing multilayer film is a thermoplastic in which an oxygen absorbent is dispersed between a conventional gas-barrier multilayer film in which a heat seal layer and a gas barrier layer are laminated, and optionally through an intermediate layer made of a thermoplastic resin. It is used as a resin layer with an oxygen absorption layer added to the outside to prevent oxygen permeation, and to absorb oxygen in the container. It is manufactured using a method (see Patent Document 1).

  However, those using oxygen absorbers such as iron powder are detected by metal detectors used for detecting foreign substances such as food, and the internal visibility is insufficient due to the problem of opacity. There was a problem that it cannot be used for beverages such as alcohol whose flavor is impaired. In addition, since the oxidation reaction of iron powder is used, the effect of oxygen absorption can be exhibited only when the material to be preserved is a high moisture type.

  On the other hand, in a composition composed of a polymer and having an oxygen scavenging property, a resin composition comprising a polyamide, particularly a xylylene group-containing polyamide and a transition metal, is known as an oxidizable organic component, and a resin composition having an oxygen scavenging function or There are also examples of oxygen absorbers obtained by molding the resin composition, packaging materials, and multilayer laminated films for packaging (see Patent Documents 2 to 6).

  However, a resin composition containing a transition metal catalyst and oxidizing a polyamide resin or the like to develop an oxygen absorbing function oxidizes the xylylene group-containing polyamide resin, resulting in a decrease in strength due to oxidative degradation of the resin, and the packaging container itself There is a problem that the strength of the glass is reduced.

  Furthermore, there is an example of MXD6, which is a polyamide obtained by polycondensation of metaxylylenediamine and adipic acid, as an example showing an oxidation reaction with a polyamide resin and a transition metal catalyst. In a system in which transition metal is mixed with MXD6, For use as an oxygen-absorbing resin composition and preserving the material to be stored well, the oxygen-absorbing ability may be low. In addition, a system in which transition metal is mixed with MXD6 usually uses a blend of a polyester resin such as polyethylene terephthalate (hereinafter referred to as PET) or a resin having a relatively high melting point such as nylon 6.

Japanese Patent Laid-Open No. 9-234832 Japanese Patent Laid-Open No. 5-140555 JP 2001-252560 A JP 2003-341747 A JP 2005-119893 A JP 2001-179090 A

  An object of the present invention is to provide an oxygen-absorbing multilayer body excellent in oxygen-absorbing performance, resin strength, interlayer strength, and resin processability, which solves the above problems.

  By using a resin composition in which a specific polyamide resin, a transition metal catalyst, a polyolefin resin, and an epoxy group-containing ethylene copolymer are blended at a specific ratio, the oxygen absorption performance is obtained by the present inventors. It has been found that an oxygen-absorbing multilayer body excellent in workability, retaining resin strength after storage, and having excellent workability and interlayer strength can be obtained.

  That is, the present invention includes at least three layers of a sealant layer made of a polyolefin resin, a polyolefin resin, a transition metal catalyst, an oxygen absorbing resin layer containing an epoxy group-containing ethylene copolymer and a polyamide resin, and a gas barrier layer made of a gas barrier substance. Are laminated in this order, and the polyamide resin is a polyamide resin having a terminal amino group concentration of 30 μeq / g or less obtained by polycondensation of aromatic diamine and dicarboxylic acid, and oxygen The content of the epoxy group-containing ethylene copolymer in the absorption resin layer is 2 to 40% by weight with respect to the total amount of the oxygen absorption resin layer, and the total content of the transition metal catalyst and the polyamide resin is the oxygen absorption resin The oxygen-absorbing multilayer body is characterized by being 15 to 60% by weight based on the total amount of the layer.

  According to the present invention, it is possible to provide an oxygen-absorbing multilayer body having an oxygen-absorbing resin layer that has high oxygen-absorbing performance, molding processability and interlayer strength, and hardly undergoes strength deterioration due to oxidation of polyamide resin.

  The oxygen-absorbing multilayer body of the present invention is obtained by laminating at least three layers of a sealant layer, an oxygen-absorbing resin layer, and a gas barrier layer in this order, and is obtained by polycondensation of an aromatic diamine and a dicarboxylic acid on the oxygen-absorbing resin layer. Oxygen-absorbing resin composition containing a polyamide resin having a terminal amino group concentration of 30 μeq / g or less (hereinafter referred to as “polyamide resin A”), a transition metal catalyst, a polyolefin resin, and an epoxy group-containing ethylene copolymer This is an oxygen-absorbing multilayer body made of a material. In addition, the multilayer body of the present invention can be used for applications in which all or part of the container body, lid, and packaging material are formed with the sealant layer inside. Details of each layer and each composition of the oxygen-absorbing multilayer body will be described below.

  Polyolefin resins used in the sealant layer of the present invention include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, ultra-low-density polyethylene, various polyethylenes such as polyethylene using a metallocene catalyst, polystyrene, polymethyl Polypropylenes such as pentene, propylene homopolymer, propylene-ethylene block copolymer and propylene-ethylene random copolymer can be used alone or in combination. These polyolefin resins include ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, if necessary. A polymer, an ethylene-methyl methacrylate copolymer, or a thermoplastic elastomer may be added. The melt flow rate of polyolefin resin (hereinafter referred to as MFR) is preferably 1 to 35 g / 10 min at 200 ° C. and 2 to 45 g / 10 min at 240 ° C. in consideration of the processability of the multilayer body. Used. In addition, MFR as used in this specification is MFR of the said resin measured on the conditions of the load of 2160g in specific temperature using the apparatus based on JISK7210, unless there is particular notice, "g / 10. Expressed with the measured temperature in units of minutes.

  The polyolefin resin used in the sealant layer of the present invention includes coloring pigments such as titanium oxide, antioxidants, slip agents, antistatic agents, stabilizers, additives such as lubricants, calcium carbonate, clay, mica, silica, etc. A filler, a deodorant and the like may be added. In particular, it is preferable to add an antioxidant in order to recycle and reprocess offcuts generated during production.

In the present invention, the polyolefin resin used for the oxygen-absorbing resin layer includes high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, ultra-low-density polyethylene, various polyethylenes such as polyethylene by metallocene catalyst, polystyrene Polypropylenes such as polymethylpentene, propylene homopolymer, propylene-ethylene block copolymer, propylene-ethylene random copolymer can be used alone or in combination. These polyolefin resins include ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, if necessary. A polymer, an ethylene-methyl methacrylate copolymer, or a thermoplastic elastomer may be added. The polyolefin resin of the oxygen-absorbing resin layer is preferably the same type as the polyolefin resin of the sealant layer, considering the processability of the resin and the adhesion to the sealant layer. The MFR of the polyolefin resin is preferably 1 to 35 g / 10 minutes at 200 ° C. and 2 to 45 g / 10 minutes at 240 ° C. in consideration of film processability. In terms of oxygen absorption performance, the oxygen permeability coefficient is preferably 80 to 200 cc · mm / (m ² · day · atm) (23 ° C. · 60% RH), and when a polyolefin resin having an oxygen permeability coefficient in this range is used, Good oxygen absorption performance can be obtained.

  The polyolefin resin used in the oxygen-absorbing resin layer of the present invention includes coloring pigments such as titanium oxide, antioxidants, slip agents, antistatic agents, stabilizers, additives such as lubricants, calcium carbonate, clay, mica, A filler such as silica or a deodorant may be added. In particular, it is preferable to add an antioxidant in order to recycle and reprocess offcuts generated during production.

  As the epoxy group-containing ethylene copolymer used in the present invention, an ethylene copolymer containing ethylene and a glycidyl ester of α, β-unsaturated carboxylic acid as a copolymerization component is preferably exemplified. Examples of the α, β-unsaturated carboxylic acid include methyl acrylate, ethyl acrylate, butyl acrylate, vinyl acetate, vinyl propionate, methyl methacrylate, ethyl methacrylate, butyl methacrylate and the like. In particular, methyl acrylate, ethyl acrylate, and vinyl acetate are preferable.

  Examples of the epoxy group-containing ethylene copolymer include a copolymer composed of ethylene units and glycidyl methacrylate units, a copolymer composed of ethylene units, glycidyl methacrylate units and methyl acrylate units, ethylene units, glycidyl methacrylate units and ethyl acrylate. Examples thereof include a copolymer composed of units, a copolymer composed of ethylene units, glycidyl methacrylate units, and vinyl acetate units.

  Addition of an epoxy group-containing ethylene copolymer to the oxygen-absorbing resin layer improves the adhesion (interlayer strength) between the oxygen-absorbing resin layer and the adjacent layer when an oxygen-absorbing multilayer body is formed. The sealing strength when bag making is also improved. The content of the epoxy group-containing ethylene copolymer in the oxygen-absorbing resin layer is preferably 2 to 40% by weight, particularly preferably 5 to 30% by weight. If the content of the epoxy group-containing ethylene copolymer is less than 2% by weight, there is no effect of improving the interlayer strength, and if it is more than 40% by weight, the cost of the film is increased and the odor of the film and the recycling of the scraps are adversely affected. Effect. The MFR of the epoxy group-containing ethylene copolymer is preferably 3 to 25 g / 10 minutes at 200 ° C. and 4 to 35 g / 10 minutes at 240 ° C. in consideration of the processability of the film.

  Examples of the transition metal catalyst used in the present invention include compounds of a first transition element such as Fe, Mn, Co, and Cu. Further, transition metal organic acid salts, chlorides, phosphates, phosphites, hypophosphites, nitrates and the like alone or a mixture thereof can be cited as examples of transition metal catalysts. Examples of the organic acid include salts of C2-C22 aliphatic alkyl acids such as acetic acid, propionic acid, octanoic acid, lauric acid, stearic acid, or malonic acid, succinic acid, adipic acid, sebacic acid, hexahydrophthalic acid A salt of a dibasic acid, a salt of butanetetracarboxylic acid, benzoic acid, toluic acid, o-phthalic acid, isophthalic acid, terephthalic acid, trimesic acid alone or a mixture thereof. Among the transition metal catalysts, an organic acid salt of Co is preferable from the viewpoint of oxygen absorption, and Co stearate is particularly preferable from the viewpoint of safety and workability.

  The transition metal catalyst is preferably added to the polyamide resin A and then mixed with the polyolefin resin and the epoxy group-containing ethylene copolymer. The transition metal catalyst is preferably added so that the concentration of all transition metals in the catalyst with respect to the polyamide resin A is 10 ppm to 5000 ppm, preferably 50 ppm to 3000 ppm. In this case, compared with the case where the addition amount is out of the above range, the oxygen absorption performance of the polyamide resin A can be improved, and the deterioration of the resin processability due to the decrease in the viscosity can be prevented.

As another method for producing the oxygen-absorbing resin composition of the present invention, an oxygen-absorbing resin composition in which a masterbatch containing a polyolefin resin and a transition metal catalyst is melt-kneaded with a polyamide resin and an epoxy group-containing ethylene copolymer is used. A production method is preferred.
The transition metal catalyst is kneaded with the polyolefin resin to produce a master batch, and then melt-mixed with the polyamide resin A and the epoxy group-containing ethylene copolymer to obtain an oxygen-absorbing resin composition. The transition metal catalyst is added so that the concentration of all transition metals in the catalyst with respect to the polyolefin resin is preferably 200 ppm to 5000 ppm, more preferably 300 ppm to 3000 ppm. In this case, the oxygen absorption performance of the polyamide resin A can be enhanced as compared with the case where the addition amount is out of the above range. Moreover, when it exceeds 5000 ppm, it may become difficult to manufacture a masterbatch, and it may become impossible to manufacture what has a uniform property. If a transition metal catalyst is added to the polyamide resin A, the resin processability is deteriorated due to a decrease in the viscosity of the polyamide resin A.

  The polyamide resin A of the oxygen-absorbing resin layer is at least a polyamide resin having a terminal amino group concentration of 30 μeq / g or less obtained by polycondensation of aromatic diamine and dicarboxylic acid. Details of the polyamide resin A will be described.

  The oxygen absorbing performance of the oxygen absorbing resin layer is considered to be better when there is more polyamide resin having oxygen absorbing ability. Surprisingly, polyamide resin A, transition metal, polyolefin resin, and epoxy group-containing ethylene copolymer It was found that when oxygen was mixed and blended at a certain ratio, it exhibited a high oxygen absorption capacity.

  The polyamide resin A in the present invention is obtained by polycondensation of an aromatic diamine and a dicarboxylic acid. The polycondensation of the aromatic diamine and the dicarboxylic acid can be carried out by melt polymerization in which the aromatic diamine and dicarboxylic acid are melted, solid phase polymerization in which the polyamide resin pellets are heated under reduced pressure, or the like.

  Examples of the aromatic diamine in obtaining the polyamide resin A include orthoxylylenediamine, paraxylylenediamine, and metaxylylenediamine, but paraxylylenediamine, metaxylylenediamine, or these from the viewpoint of oxygen absorption performance. A mixture is preferably used, and metaxylylenediamine is particularly preferably used. In addition, various aliphatic diamines and aromatic diamines may be incorporated as copolymerization components as long as the performance is not affected.

  Examples of the dicarboxylic acid for obtaining the polyamide resin A include adipic acid, azelaic acid, sebacic acid, dodecanoic acid, isophthalic acid, terephthalic acid, and malonic acid. Among these, from the viewpoint of oxygen absorption performance, adipic acid, sebacic acid, isophthalic acid or a mixture thereof is preferable, and a mixture of adipic acid and sebacic acid or a mixture of adipic acid and isophthalic acid is particularly preferable. The molar ratio in the case of using a mixture of adipic acid and sebacic acid is preferably sebacic acid: adipic acid = 0.3-0.7: 0.7-0.3, and 0.4-0.6: 0.6 -0.4 is particularly preferred. Further, when using a mixture of adipic acid and isophthalic acid, adipic acid: isophthalic acid is preferably 0.7 to 0.97: 0.3 to 0.03, and 0.8 to 0.95: 0.2 to 0 .05 is particularly preferred. In addition, various aliphatic dicarboxylic acids and aromatic dicarboxylic acids may be incorporated as copolymerization components as long as the performance is not affected.

  The polyamide resin A in the present invention is a polyamide resin having a terminal amino group concentration of 30 μeq / g or less obtained by polycondensation of at least an aromatic diamine and a dicarboxylic acid, but has a terminal amino group concentration of 25 μeq / g or less. And oxygen absorption performance are improved, and it is more preferably 20 μeq / g or less because oxygen absorption performance is further improved. Thus, the oxygen absorption performance tends to improve as the terminal amino group concentration decreases, and it is preferable to reduce the concentration as much as possible. However, in consideration of economic rationality, the lower limit is 5 μeq / g or more. It is preferable to do. If the terminal amino group concentration is higher than 30 μeq / g, good oxygen absorption performance cannot be obtained.

In order to reduce the terminal amino group concentration of the polyamide resin to 30 μeq / g or less,
1) Method for carrying out polycondensation by adjusting the molar ratio of aromatic diamine and dicarboxylic acid 2) Method for reacting polyamide resin with carboxylic acid to seal the terminal amino group 3) Method for solid-phase polymerization of polyamide resin These methods are preferably carried out, and these methods can be carried out alone or in combination. In particular, the combination of the methods 1), 3), 2) and 3) is preferable because a polyamide resin having better oxygen absorption performance and moldability at the time of producing a multilayer body can be obtained. Hereinafter, these methods will be described.

  1) In the method of carrying out polycondensation by adjusting the molar ratio of aromatic diamine and dicarboxylic acid, dicarboxylic acid is used excessively with respect to aromatic diamine. Specifically, aromatic diamine and dicarboxylic acid are used. The molar ratio (aromatic diamine / dicarboxylic acid) is preferably 0.985 to 0.997, particularly preferably 0.988 to 0.995. When the molar ratio is less than 0.985, it is difficult to increase the degree of polymerization of the polyamide resin.

  2) In the method of reacting the polyamide resin with carboxylic acid to seal the terminal amino group, the terminal amino group concentration of the polyamide resin is reacted with the carboxylic acid to adjust the terminal amino group concentration. The carboxylic acid to be used is not particularly limited, but a carboxylic anhydride is preferable, and specifically, phthalic anhydride, maleic anhydride, benzoic anhydride, glutaric anhydride, itaconic anhydride, citraconic anhydride, acetic anhydride, anhydrous Examples include butyric acid, isobutyric anhydride, trimellitic anhydride, pyromellitic anhydride, and the like. The polyamide resin and the carboxylic acid can be reacted by, for example, a method of adding at the time of melt polymerization or a method of adding a carboxylic acid to the polyamide resin obtained by melt polymerization and then melt-kneading the polyamide resin. In order to increase the degree of polymerization, melt kneading is preferred.

  3) In the method of solid-phase polymerization of polyamide resin, the terminal amino group concentration is adjusted by further subjecting the polyamide resin obtained by melt polymerization to a solid-phase polymerization reaction. Solid phase polymerization proceeds by heating polyamide resin pellets under reduced pressure. The pressure during the solid phase polymerization is preferably 100 torr or less, and more preferably 30 torr or less. Further, the temperature at the time of solid phase polymerization needs to be 130 ° C. or higher, more preferably 150 ° C. or higher, and preferably 10 ° C. or higher, more preferably 15 ° C. or lower than the melting point of the polyamide resin. The solid state polymerization time is preferably 3 hours or more. By performing solid phase polymerization, the terminal amino group concentration of the polyamide resin is decreased, the molecular weight is increased, and the viscosity can be adjusted.

  As the polyamide resin A of the present invention, those having low crystallinity are preferably used. Specifically, those having a low crystallinity with a half-crystallization time of 150 seconds or more, or those having no melting point peak when the melting point is measured by DSC are preferable. When the half crystallization time of the polyamide resin A is 150 seconds or more, higher oxygen absorption performance can be obtained.

  Further, the polyamide resin A preferably has a low melting point and glass transition temperature (hereinafter referred to as Tg) in consideration of processability and oxygen absorption performance with a polyolefin resin. The melting point of the polyamide resin A is preferably 200 ° C. or lower, more preferably 190 ° C. or lower or a resin having no melting point. Tg is preferably 90 ° C. or lower, and particularly preferably 80 ° C. or lower.

The oxygen permeability coefficient of the polyamide resin A is preferably 0.2 to 1.5 cc · mm / (m ² · day · atm) (23 ° C. · 60% RH), and 0.3 to 1.0 cc · mm / (m ² · day · atm) (23 ° C. · 60% RH) is more preferable. When the oxygen permeability coefficient is 0.2 to 1.5 cc · mm / (m ² · day · atm) (23 ° C. · 60% RH), when the polyamide resin A and the polyolefin resin are blended, higher oxygen absorption performance is obtained. can get.

  When the polyamide resin A, the polyolefin resin, and the epoxy group-containing ethylene copolymer are mixed, the MFR of the polyamide resin A is 3 to 20 g / 10 minutes at 200 ° C. and 4 to 25 g at 240 ° C. in consideration of processability. / 10 minutes are preferably used. In this case, when the resin is processed at a temperature where the difference between the MFR of the polyolefin resin and the MFR of the polyamide resin A is ± 20 g / 10 minutes, preferably ± 10 g / 10 minutes, the kneaded state becomes good, and a film or sheet is obtained. In this case, a processed product having no problem in appearance can be obtained. The MFR of the polyamide resin A can be adjusted by adjusting the molecular weight, for example. Examples of a method for adjusting the molecular weight include a method of adding a phosphorus compound as a polymerization accelerator and a method of solid-phase polymerization after melt polymerization of the polyamide resin A.

  The polyamide resin A obtained by polycondensation of an aromatic diamine and a dicarboxylic acid is preferably synthesized by a method that undergoes two steps of solid phase polymerization after melt polymerization. The number average molecular weight of the polyamide resin A is preferably 18000 to 27000, particularly preferably 20000 to 26000.

  You may add a stabilizer etc. to the polyamide resin A obtained by this invention suitably. In particular, phosphorus compounds are preferably used as stabilizers, and specifically, diphosphites are preferable. The phosphorus compound is preferably not more than 200 ppm, particularly preferably not more than 100 ppm because the polyamide resin A is stable and affects the oxygen absorption performance.

The total content of the transition metal catalyst and the polyamide resin A in the oxygen absorbing resin layer is 15 to 60% by weight, preferably 17 to 60% by weight, more preferably 20 to 60% by weight, and 25 to 50% by weight. Particularly preferred. When the content of the polyamide resin A containing the transition metal catalyst in the oxygen-absorbing resin composition is less than 15% by weight or exceeds 60% by weight, the oxygen-absorbing ability is lowered. On the other hand, if it exceeds 60% by weight, resin degradation due to oxidation of the polyamide resin A occurs, causing problems such as strength reduction.
When melt-kneading the master batch of the present invention, the polyamide resin A and the epoxy group-containing ethylene copolymer, the content of the polyamide resin A and the transition metal concentration can be adjusted by simultaneously adding the polyolefin resin.

  As the gas barrier material used in the gas barrier layer of the present invention, a gas barrier thermoplastic resin, a gas barrier thermosetting resin, various deposited films such as silica, alumina, and aluminum, and a metal foil such as an aluminum foil can be used. Examples of the gas barrier thermoplastic resin include ethylene-vinyl alcohol copolymer, MXD6, and polyvinylidene chloride. Examples of the gas barrier thermosetting resin include a gas barrier epoxy resin such as “MAXIVE” manufactured by Mitsubishi Gas Chemical Co., Ltd.

  Although there is no restriction | limiting in particular in the thickness of an oxygen absorption resin layer, 5-200 micrometers is preferable and 10-100 micrometers is especially preferable. In this case, as compared with the case where the thickness is out of the above range, the oxygen absorbing resin layer can further improve the performance of absorbing oxygen and can prevent the workability and the economy from being impaired. Further, the thickness of the sealant layer is preferably smaller because the sealant layer becomes a separation layer from the oxygen-absorbing resin layer, but is preferably 5 to 200 μm, particularly preferably 10 to 80 μm. In this case, as compared with the case where the thickness is out of the above range, the oxygen absorption rate of the oxygen-absorbing resin layer can be further increased, and the workability can be prevented from being impaired.

  As the gas barrier resin, the thickness when the thermoplastic resin is used for the gas barrier layer is preferably 5 to 200 μm, particularly preferably 10 to 100 μm. Further, when a thermosetting resin such as an amine-epoxy curing agent is used for the gas barrier adhesive layer as the gas barrier resin, 0.1 to 100 μm is preferable, and 0.5 to 20 μm is particularly preferable. When the thickness is within the above range, the gas barrier property can be further improved and the workability and economy can be prevented from being impaired as compared with the case where the thickness is not within the above range.

  Considering the processability of the deoxidizing multilayer body, the thickness ratio of the sealant layer and the oxygen-absorbing resin layer is preferably 1: 0.5 to 1: 3, particularly 1: 1 to 1: 2.5. preferable. Furthermore, in consideration of processability, it is preferable to interpose an intermediate layer made of polyolefin resin between the gas barrier layer and the oxygen-absorbing resin layer. The thickness of the intermediate layer is preferably substantially the same as the thickness of the sealant layer from the viewpoint of workability. In this case, considering variations due to processing, the thickness is the same if the thickness ratio is within ± 10%.

  The oxygen-absorbing multilayer body of the present invention includes a sealant layer made of a polyolefin resin, an oxygen-absorbing resin layer containing at least a polyolefin resin, an epoxy group-containing ethylene copolymer, a transition metal catalyst and a polyamide resin A, and a gas barrier made of a gas barrier substance. At least three layers are laminated in this order, but other layers may be added.

  For example, in order to prevent damage to the gas barrier layer and pinholes, it is preferable to provide a protective layer made of a thermoplastic resin inside and outside the gas barrier layer. Examples of the resin used for the protective layer include polyethylenes such as high density polyethylene, polypropylenes such as propylene homopolymer, propylene-ethylene random copolymer, propylene-ethylene block copolymer, nylon 6, nylon 6,6 and the like. Polyamides, polyesters such as PET, and combinations thereof.

  About the manufacturing method of an oxygen absorption multilayer body, well-known methods, such as a co-extrusion method, various lamination methods, and various coating methods, can be utilized according to the property of various materials, the process objective, a process process, etc. For example, for film or sheet molding, a resin composition melted through a T die, a circular die, or the like is extruded from an attached extruder, or an oxygen absorbing film or sheet is coated with an adhesive. There is a method of manufacturing by bonding to a film or sheet. In addition, by using an injection machine, molten resin can be molded into a multilayer container having a predetermined shape by co-injection or sequential injection into an injection mold through a multilayer multiple die.

  The oxygen-absorbing multilayer body of the present invention can be prepared as a film, processed into a bag shape and a lid material, and used. In addition, a paper base material can be laminated on the outer layer of the gas barrier layer to be used as an oxygen-absorbing paper container. In consideration of processability when laminated with a paper base material to obtain a paper container, the inner portion of the gas barrier layer is preferably 60 μm or less, particularly preferably 50 μm or less. When the internal thickness is larger than that of the gas barrier layer, a problem arises in processability to a container when a paper base material is laminated and formed into a container shape.

  Further, the oxygen-absorbing multilayer body of the present invention is produced as a sheet, and a predetermined method such as tray, cup, bottle, tube, PTP (press-through pack) or the like is formed by a molding method such as vacuum forming, pressure forming, or plug assist molding. It can be thermoformed into a shaped oxygen absorbing multilayer container. Moreover, the obtained oxygen absorption multilayer container can perform 80-100 degreeC boil processing, 100-135 degreeC semi-retort, a retort, and a high retort process. Moreover, it is preferably used for a microwave cooking-compatible pouch that fills a bag-like container with contents such as food, provides an opening, and releases steam from the opening when cooking with a microwave oven. it can.

  By using the oxygen-absorbing multilayer body of the present invention in a part or all of the sealing packaging container with the sealant layer on the inside, the oxygen in the container is absorbed in addition to oxygen that slightly enters from the outside of the container. It is possible to prevent deterioration of the contents stored in the container.

  Since the oxygen-absorbing multilayer body of the present invention can absorb oxygen regardless of the presence or absence of moisture in the object to be preserved, it can dry powder seasonings, powdered coffee, coffee beans, rice, tea, beans, rice crackers, rice crackers, etc. It can be suitably used for foods, pharmaceuticals, health foods such as vitamins, and industrial materials such as electronic parts. In addition, the oxygen-absorbing multilayer body of the present invention is different from the conventional oxygen-absorbing multilayer body using iron powder in order to sterilize containers such as alcoholic beverages, carbonated beverages, acetic acid-containing foods that cannot be stored in the presence of iron. It can use suitably for the use which sterilizes hydrogen peroxide.

  Other items to be preserved include processed rice such as polished rice, cooked rice, red rice and rice cake, cooked foods such as soup, stew and curry, confectionery such as fruit, sheep, pudding, cake and buns, tuna and fish shellfish. Fish products such as cheese, butter and other dairy products, meat, salami, sausage, ham and other processed meat products, carrots, potatoes, asparagus, shiitake mushrooms, and eggs.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In the examples and comparative examples, various physical property values were measured by the following measuring methods and measuring apparatuses.

(Measurement method of Tg)
Tg was measured according to JIS K7122. The measuring apparatus used was “DSC-60” manufactured by Shimadzu Corporation.

(Measuring method of melting point)
The melting point was determined by measuring the DSC melting peak temperature according to ISO11357. The measuring apparatus used was “DSC-60” manufactured by Shimadzu Corporation.

(Measurement method of number average molecular weight)
The number average molecular weight was measured by GPC-LALLS. As a measuring apparatus, “Shodex GPC-2001” manufactured by Showa Denko KK was used.

(Measurement method of MFR)
The MFR of each resin is measured under a load of 2160 g at a specific temperature using an apparatus in accordance with JIS K7210 (“Melt Indexer” manufactured by Toyo Seiki Seisakusho Co., Ltd.), and the value is described together with the temperature. (Unit: “g / 10 min”). In addition, when MFR was measured based on JISK7210, it was described that much.

(Measurement method of oxygen permeability coefficient)
The oxygen transmission coefficient was measured using “OX-TRAN-2 / 21” manufactured by MOCON under the conditions of 23 ° C., 60% RH and a cell area of 50 cm ² .

(Method for measuring terminal amino group concentration)
0.5 g of sample was dissolved in 30 mL of phenol / ethanol = 4/1 (volume ratio), 5 mL of methanol was added, and an automatic titrator with 0.01 N hydrochloric acid as a titrant (“COM-2000” manufactured by Hiranuma Seisakusho) Titration with The same operation titrated without adding a sample was used as a blank, and the terminal amino group concentration was calculated from the following formula.
Terminal amino group concentration (μeq / g) = (A−B) × f × 10 / C
(A: titer (mL), B: blank titer (mL), f: factor of normal solution, C: sample amount (g)).

(Measurement method of terminal carboxyl group concentration)
0.5 g of a sample was dissolved in 30 mL of benzyl alcohol, 10 mL of methanol was added, and titrated with an automatic titration apparatus (“COM-2000” manufactured by Hiranuma Seisakusho) with 0.01 N sodium hydroxide solution as a titrant. The same operation titrated without adding a sample was used as a blank, and the terminal carboxyl group concentration was calculated from the following formula.
Terminal carboxyl group concentration (μeq / g) = (A−B) × f × 10 / C
(A: titer (mL), B: blank titer (mL), f: factor of normal solution, C: sample amount (g)).

(Measurement method of semi-crystallization time)
When the pellet is melted at each temperature and the resin is crystallized at each temperature, the time for all to crystallize is called the crystallization time, and the time for reaching 50% crystallization is called the semi-crystallization time. The half crystallization time was measured by the depolarized intensity method. That is, when the sample pellets are irradiated with light and the sample pellets are crystallized, the amount of light transmission decreases and becomes stable when the amount of light transmission is stabilized. The time is defined as the crystallization time, and the amount of light transmission is 50%. The time to reach was defined as the half crystallization time. Although the crystallization time and the half crystallization time differ depending on the measurement temperature, in the following description, among the half crystallization times at each temperature, the one with the shortest half crystallization time is referred to as “half crystallization time”. Described. In addition, a “polymer crystallization rate measuring apparatus MK-701 type” manufactured by Kotaki was used to measure the crystallization time and the semi-crystallization time.

(Synthesis conditions by melt polymerization of polyamide resin)
After heating and melting the dicarboxylic acid in a reaction can at 170 ° C., the aromatic diamine is gradually and continuously added so that the molar ratio of the dicarboxylic acid to the dicarboxylic acid is about 1: 1 while stirring the contents. And the temperature was raised to 240 ° C. After completion of the dropwise addition, the temperature was raised to 260 ° C. or higher and the reaction was continued. After completion of the reaction, the inside of the reaction can was slightly pressurized with nitrogen, the strand was extruded from a die head having holes, and pelletized with a pelletizer.

(Synthesis conditions by solid phase polymerization of polyamide resin)
The pellets obtained by melt polymerization by the above method were charged into a rotary tumbler equipped with a heating device, the pressure inside the tumbler was reduced to 1 torr or less while rotating, and the operation of bringing the pressure to normal pressure with nitrogen was performed three times. Thereafter, the inside of the apparatus was heated while rotating the tumbler to 30 torr or less, the inside of the apparatus was adjusted to 150 ° C. or more, and the reaction was performed at that temperature for a predetermined time. Then, it cooled to 60 degreeC and obtained the polyamide resin.

(Example 1)
Polyamide resin was synthesized by performing melt polymerization and solid phase polymerization under the above synthesis conditions using metaxylylenediamine: sebacic acid: adipic acid in a molar ratio of 0.993: 0.45: 0.55. (Hereinafter, the polyamide resin is referred to as polyamide 1). The dropping time was 2 hours, the reaction time for melt polymerization was 1 hour, the pressure in the apparatus during solid phase polymerization was 1 torr or less, the polymerization temperature was 160 ° C., and the polymerization time was 4 hours. Polyamide 1 has a Tg of 72 ° C., a melting point of 175 ° C., a semi-crystallization time of 2000 seconds or more, a terminal amino group concentration of 14.5 μeq / g, a terminal carboxyl group concentration of 65.2 μeq / g, a number average molecular weight of 25,000, and an MFR of 240 ° C. It was 10.8 g / 10 minutes. Moreover, when the unstretched film was produced with the obtained polyamide 1 single-piece | unit and the oxygen permeability coefficient was calculated | required, it was 0.40cc * mm / (m < ² > * day * atm) (23 degreeC * 60% RH). . These results are shown in Table 1.

  Cobalt stearate was added to polyamide 1 as a transition metal catalyst by a side feed to molten polyamide 1 with a twin screw extruder so as to have a cobalt concentration of 400 ppm. Furthermore, linear low density polyethylene (product name: Ube Maruzen Polyethylene Co., Ltd.) “Umerit” is used as a polyolefin resin in a mixture of the obtained polyamide and cobalt stearate (hereinafter referred to as cobalt stearate-containing polyamide 1). 4040F ", MFR 4.0 g / 10 min (measured according to JIS K7210), 240 ° C. MFR 7.9 g / 10 min, 250 ° C. MFR 8.7 g / 10 min, hereinafter referred to as LLDPE1), and epoxy group-containing As an ethylene copolymer, an ethylene-glycidyl methacrylate copolymer (product name: “Bond First E” manufactured by Sumitomo Chemical Co., Ltd.), MFR 3.0 g / min (measured in accordance with JIS K7210), MFR 10.0 g at 240 ° C. / 10 minutes, 250 ° C. MFR 11.1 g / 10 minutes, hereinafter referred to as EGMA Is melt kneaded at 240 ° C. in a weight ratio of cobalt stearate-containing polyamide 1: LLDPE1: EGMA = 40: 50: 10 to obtain oxygen-absorbing resin pellets A.

  The obtained oxygen-absorbing resin pellet A was used as an oxygen-absorbing resin layer, and linear low-density polyethylene (product name: “Novatech LL UF641” manufactured by Nippon Polyethylene Co., Ltd.), MFR 2.1 g / 10 min (according to JIS K7210) Measurement), MFR 6.4 g / 10 min at 240 ° C., MFR 8.8 g / 10 min at 250 ° C., hereinafter referred to as LLDPE2)), a two-layer / three-layer film 1 (thickness: intermediate LLDPE2) Layer 10 μm / oxygen-absorbing resin layer 20 μm / sealant LLDPE2 layer 10 μm) was subjected to corona discharge treatment at 60 m / min with a width of 760 mm to produce a film roll. The film roll had no uneven thickness such as bumps, the appearance of the obtained film was good, and the HAZE was 18%. Nylon film A (product name: Toyobo Co., Ltd.) using urethane-type dry laminate adhesive (product name: “AD-817 / CAT-RT86L-60” manufactured by Toyo Morton Co., Ltd.) on the corona-treated surface side “N1202”) and alumina-deposited PET film (product name: “GL-ARH-F” manufactured by Toppan Printing Co., Ltd.) are laminated, and alumina-deposited PET film (12) / adhesive (3) / nylon film A ( 15) An oxygen-absorbing multilayer film composed of an oxygen-absorbing multilayer body of / adhesive (3) / LLDPE2 (10) / oxygen-absorbing resin (20) / LLDPE2 (10) was obtained. The numbers in parentheses mean the thickness of each layer (unit: μm). Next, a 10 cm x 15 cm three-sided sealed bag with the sealant layer side as the inner surface was prepared. After hot filling with 60 g of pineapple and 60 g of fruit syrup at 80 ° C, it was sealed so that the headspace air volume was 5 cc. A boil treatment for 30 minutes was performed. Thereafter, the remaining specimen was stored at 40 ° C., and the flavor and color of the pineapple after 1 month, 3 months, and 6 months, and the seal strength after 6 months of storage were investigated. These results are shown in Table 2.

(Example 2)
After obtaining an oxygen-absorbing multilayer film in the same manner as in Example 1 except that the weight ratio at the time of melt-kneading was changed to cobalt stearate-containing polyamide 1: LLDPE1: EGMA = 40: 55: 5, a three-side sealed bag was prepared. Then, the same storage test as in Example 1 was performed. These results are shown in Table 2.

(Example 3)
After obtaining an oxygen-absorbing multilayer film in the same manner as in Example 1 except that the weight ratio at the time of melt kneading was changed to cobalt stearate-containing polyamide 1: LLDPE1: EGMA = 40: 40: 20, a three-side sealed bag was produced. Then, the same storage test as in Example 1 was performed. These results are shown in Table 2.

Example 4
After obtaining an oxygen-absorbing multilayer film in the same manner as in Example 1 except that the weight ratio at the time of melt-kneading was changed to cobalt stearate-containing polyamide 1: LLDPE1: EGMA = 40: 25: 35, a three-side sealed bag was produced. Then, the same storage test as in Example 1 was performed. These results are shown in Table 2.

(Example 5)
After obtaining an oxygen-absorbing multilayer film in the same manner as in Example 1 except that the weight ratio at the time of melt-kneading was changed to cobalt stearate-containing polyamide 1: LLDPE1: EGMA = 55: 35: 10, a three-side sealed bag was prepared. Then, the same storage test as in Example 1 was performed. These results are shown in Table 2.

(Example 6)
After obtaining an oxygen-absorbing multilayer film in the same manner as in Example 1 except that the weight ratio during melt-kneading was changed to cobalt stearate-containing polyamide 1: LLDPE1: EGMA = 25: 70: 5, a three-side sealed bag was prepared. Then, the same storage test as in Example 1 was performed. These results are shown in Table 2.

(Example 7)
After obtaining an oxygen-absorbing multilayer film in the same manner as in Example 1 except that the weight ratio at the time of melt-kneading was changed to cobalt stearate-containing polyamide 1: LLDPE1: EGMA = 17: 73: 10, a three-side sealed bag was prepared. Then, the same storage test as in Example 1 was performed. These results are shown in Table 2.

(Example 8)
Polyamide resin was synthesized by performing melt polymerization and solid phase polymerization under the above-mentioned synthesis conditions using metaxylylenediamine: sebacic acid: adipic acid in a molar ratio of 0.993: 0.3: 0.7. (Hereinafter, the polyamide resin is referred to as polyamide 2). The dropping time was 2 hours, the reaction time for melt polymerization was 1 hour, the pressure in the apparatus during solid phase polymerization was 1 torr or less, the polymerization temperature was 160 ° C., and the polymerization time was 4 hours. Polyamide 2 has a Tg of 73 ° C., a melting point of 194 ° C., a crystallization time of 2000 seconds or more, a terminal amino group concentration of 15.8 μeq / g, a terminal carboxyl group concentration of 64.5 μeq / g, a number average molecular weight of 25200, and an MFR of 240 ° C. It was 11.0 g / 10 minutes. In addition, an unstretched film was prepared from the obtained polyamide 2 alone, and its oxygen permeability coefficient was determined to be 0.21 cc · mm / (m ² · day · atm) (23 ° C. · 60% RH). . These results are shown in Table 1. .

  Thereafter, in the same manner as in Example 1, cobalt stearate was added so as to have a cobalt concentration of 400 ppm, and the obtained polyamide 2 and cobalt stearate mixture (hereinafter referred to as cobalt stearate-containing polyamide 2) was added to LLDPE1. And EGMA were melt kneaded at 240 ° C. in a weight ratio of cobalt stearate-containing polyamide 2: LLDPE1: EGMA = 40: 50: 10 to obtain oxygen-absorbing resin pellets. Further, after obtaining an oxygen-absorbing multilayer film in the same manner as in Example 1, a three-side sealed bag was produced, and the same storage test as in Example 1 was performed. These results are shown in Table 2.

Example 9
Polyamide resin was synthesized by performing melt polymerization and solid phase polymerization under the above-mentioned synthesis conditions using metaxylylenediamine: sebacic acid: adipic acid in a molar ratio of 0.993: 0.7: 0.3. (Hereinafter, the polyamide resin is referred to as polyamide 3). The dropping time was 2 hours, the reaction time for melt polymerization was 1 hour, the pressure in the apparatus during solid phase polymerization was 1 torr or less, the polymerization temperature was 160 ° C., and the polymerization time was 4 hours. Polyamide 3 has a Tg of 65 ° C., a melting point of 170 ° C., a semicrystallization time of 2000 seconds or more, a terminal amino group concentration of 16.2 μeq / g, a terminal carboxyl group concentration of 66.2 μeq / g, a number average molecular weight of 24500, and an MFR of 240 ° C. It was 10.8 g / 10 minutes. In addition, an unstretched film was prepared from the obtained polyamide 3 alone, and its oxygen permeability coefficient was determined to be 0.84 cc · mm / (m ² · day · atm) (23 ° C. · 60% RH). . These results are shown in Table 1. .

  Thereafter, in the same manner as in Example 1, cobalt stearate was added so as to have a cobalt concentration of 400 ppm, and LLDPE1 was added to the obtained mixture of polyamide 3 and cobalt stearate (hereinafter referred to as cobalt stearate-containing polyamide 3). And EGMA were melt-kneaded at 240 ° C. in a weight ratio of cobalt stearate-containing polyamide 3: LLDPE1: EGMA = 40: 50: 10 to obtain oxygen-absorbing resin pellets. Further, after obtaining an oxygen-absorbing multilayer film in the same manner as in Example 1, a three-side sealed bag was produced, and the same storage test as in Example 1 was performed. These results are shown in Table 2.

(Example 10)
Polyamide resin was synthesized by performing melt polymerization and solid phase polymerization under the above-mentioned synthesis conditions using metaxylylenediamine: adipic acid: isophthalic acid in a molar ratio of 0.992: 0.95: 0.05. (Hereinafter, the polyamide resin is referred to as polyamide 4). The dropping time was 2 hours, the reaction time for melt polymerization was 1 hour, the pressure in the apparatus during solid phase polymerization was 1 torr or less, the polymerization temperature was 205 ° C., and the polymerization time was 4 hours. This polyamide 4 had a Tg of 94 ° C., a melting point of 228 ° C., a half crystallization time of 300 seconds, a terminal amino group concentration of 14.2 μeq / g, a terminal carboxyl group concentration of 69.2 μeq / g, and a number average molecular weight of 24,000. Since it was near melting | fusing point at 240 degreeC, MFR was not able to be measured, MFR of 250 degreeC was measured, and MFR in 250 degreeC was 13.5 g / 10min. An unstretched film was prepared from the obtained polyamide 4 alone, and the oxygen permeability coefficient was determined. The oxygen permeability coefficient was 0.08 cc · mm / (m ² · day · atm) (23 ° C. · 60% RH). there were. These results are shown in Table 1. .

  Thereafter, the addition of cobalt stearate to polyamide 4 and melt-kneading with LLDPE1 and EGMA were performed in the same manner as in Example 1 except that the temperature at the time of melt-kneading was 250 ° C. After obtaining an oxygen-absorbing multilayer film, a three-side sealed bag was prepared and the same storage test as in Example 1 was performed. These results are shown in Table 2.

(Example 11)
Metaxylylenediamine and paraxylylenediamine are mixed at a ratio of 7: 3. These diamines and adipic acid are used in a molar ratio of 1: 1, and only a melt polymerization is performed under the above synthesis conditions to obtain a polyamide resin. After synthesis, the terminal amino group concentration was measured (the terminal amino group concentration was 36.7 μeq / g). Next, after adding 1.5 equivalents of phthalic anhydride as a terminal blocking agent to the terminal amino group concentration, it is melt-kneaded at 270 ° C. with a twin-screw extruder to seal the terminal amino group to obtain a polyamide resin. Synthesized (hereinafter, the polyamide resin is referred to as polyamide 5). However, the dropping time was 2 hours, the polymerization temperature after completion of dropping of metaxylylenediamine in melt polymerization was 277 ° C., and the reaction time was 30 minutes. This polyamide 5 had a Tg of 87 ° C., a melting point of 259 ° C., a half crystallization time of 18 seconds, a terminal amino group concentration of 26.1 μeq / g, a terminal carboxyl group concentration of 78.0 μeq / g, and a number average molecular weight of 20,400. Moreover, since it was near melting | fusing point at 250 degreeC, MFR was not able to be measured, MFR of 270 degreeC was measured, and MFR in 270 degreeC was 28.4 g / 10min. An unstretched film was prepared from the obtained polyamide 5 alone, and the oxygen permeability coefficient was determined. The oxygen permeability coefficient was 0.13 cc · mm / (m ² · day · atm) (23 ° C. · 60% RH). there were. These results are shown in Table 1.

(Example 12)
Cobalt stearate was added to LLDPE by side feed to the melted LLDPE with a twin screw extruder so that the cobalt concentration was 600 ppm. Further, polyamide 1 was melt-kneaded at 240 ° C. in a weight ratio of polyamide 1: cobalt stearate-containing LLDPE 1: EGMA = 40: 50: 10 to the obtained mixture of LLDPE and cobalt stearate, and oxygen-absorbing resin pellets Got.

  After obtaining an oxygen-absorbing multilayer film in the same manner as in Example 1, a three-side sealed bag was prepared and the same storage test as in Example 1 was performed. These results are shown in Table 2.

  Thereafter, the addition of cobalt stearate to polyamide 5 and melt-kneading with LLDPE1 and EGMA were carried out in the same manner as in Example 1 except that the temperature during melt-kneading was changed to 270 ° C. After obtaining an oxygen-absorbing multilayer film, a three-side sealed bag was prepared and the same storage test as in Example 1 was performed. These results are shown in Table 2.

(Comparative Example 1)
An oxygen-absorbing multilayer film was obtained in the same manner as in Example 1 except that EGMA was not used and the weight ratio at the time of melt kneading was changed to cobalt stearate-containing polyamide 1: LLDPE1 = 40: 60. The same storage test as in Example 1 was performed. These results are shown in Table 2.

(Comparative Example 2)
A three-side sealed bag was prepared after obtaining an oxygen-absorbing multilayer film in the same manner as in Example 1 except that the weight ratio during melt-kneading was changed to cobalt stearate-containing polyamide 1: LLDPE1: EGMA = 10: 85: 5. Then, the same storage test as in Example 1 was performed. These results are shown in Table 2.

(Comparative Example 3)
After obtaining an oxygen-absorbing multilayer film in the same manner as in Example 1 except that the weight ratio at the time of melt-kneading was changed to cobalt stearate-containing polyamide 1: LLDPE1: EGMA = 70: 20: 10, a three-side sealed bag was prepared. Then, the same storage test as in Example 1 was performed. These results are shown in Table 2.

(Comparative Example 4)
A polyamide resin was synthesized in the same manner as in Example 1 except that the molar ratio of metaxylylenediamine: sebacic acid: adipic acid was 0.999: 0.45: 0.55 (hereinafter referred to as the polyamide resin). Is denoted as polyamide 6). This polyamide 6 had a Tg of 72 ° C., a melting point of 175 ° C., a half crystallization time of 2000 seconds or more, a terminal amino group concentration of 37.1 μeq / g, a terminal carboxyl group concentration of 50.2 μeq / g, and a number average molecular weight of 22500. Moreover, MFR in 240 degreeC was 15.0 g / 10min. Moreover, when an unstretched film was prepared from the obtained polyamide 6 alone and its oxygen permeability coefficient was determined, it was 0.40 cc · mm / (m ² · day · atm) (23 ° C. · 60% RH). . These results are shown in Table 1. .

  Thereafter, in the same manner as in Example 1, addition of cobalt stearate to polyamide 6 and melt kneading with LLDPE1 and EGMA, etc. were carried out to produce a film in the same manner as in Example 1, and then a three-side sealed bag was produced. The same storage test as in Example 1 was performed. These results are shown in Table 2.

(Comparative Example 5)
A polyamide resin was synthesized in the same manner as in Example 1 except that metaxylylenediamine and adipic acid were used in a molar ratio of 0.995: 1 and the polymerization time for solid phase polymerization was 2 hours (hereinafter referred to as “polyamide resin”). The polyamide resin is expressed as polyamide 7). Polyamide 7 had a Tg of 78 ° C., a melting point of 237 ° C., a half crystallization time of 25 seconds, a terminal amino group concentration of 33.3 μeq / g, a terminal carboxyl group concentration of 75.6 μeq / g, and a number average molecular weight of 20000. Moreover, since it was near melting | fusing point at 240 degreeC, MFR was not able to be measured, MFR of 260 degreeC was measured, and MFR in 260 degreeC was 25.9 g / 10min. An unstretched film was prepared from the obtained polyamide 7 alone, and the oxygen permeability coefficient was determined. The oxygen permeability coefficient was 0.09 cc · mm / (m ² · day · atm) (23 ° C. · 60% RH). there were. These results are shown in Table 1. .

  Thereafter, except that the temperature at the time of melt kneading was changed to 260 ° C., the addition of cobalt stearate to polyamide 7 and the melt kneading with LLDPE 1 and EGMA were carried out in the same manner as in Example 1. After manufacturing, a three-side sealed bag was produced and the same storage test as in Example 1 was performed. These results are shown in Table 2.

  As is clear from Examples 1 to 12, the oxygen-absorbing multilayer body of the present invention is excellent in oxygen absorption performance, processability, and strength, and can retain high sealing strength when processed into a bag or the like. Therefore, the color tone of the contents could be confirmed.

  In contrast, in Comparative Example 1 in which the epoxy group-containing ethylene copolymer was not added to the oxygen-absorbing resin layer, the sealing strength was lowered after boiling.

  On the other hand, compared with Example 1, in Comparative Example 4 in which the molar ratio of diamine to dicarboxylic acid was increased and in Comparative Example 5 in which the solid phase polymerization time was shortened, the terminal amino group concentration exceeded 30 μeq / g, which was good. Oxygen absorption performance could not be obtained. In Comparative Example 5, the appearance of the film was also deteriorated.

(Example 13)
In the same manner as in Example 1, a two-kind three-layer film 1 was produced, and this was used for extrusion laminating with low-density polyethylene (product name: “Mirason 18SP” manufactured by Mitsui Chemicals, Inc.), and bleached kraft paper (tsubo 340 g / m ² ) / urethane-based dry laminate adhesive (product name: “AD-817 / CAT-RT86L-60” manufactured by Toyo Morton Co., Ltd., 3) / alumina-deposited PET film (product name: letterpress printing ( "GL-ARH-F", 12) / urethane anchor coating agent ("EL-557A / B", 0.5) manufactured by Toyo Morton Co., Ltd./low density polyethylene (20) / LLDPE2 (10) An oxygen-absorbing multilayer paper base material of / oxygen-absorbing resin composition (20) / LLDPE2 (10) was obtained. This base material was formed into a 1-liter paperbell-top type paper container. The moldability of the container was good. This paper container was filled with rice shochu, sealed, and stored at 23 ° C. The oxygen concentration in the paper container after 1 month and 3 months was 0.1% or less, and the flavor of the rice shochu was well maintained.

(Example 14)
In place of LLDPE1, ethylene-propylene block copolymer (product name: “NOVATEC FG3DC” manufactured by Nippon Polypro Co., Ltd., MFR 9.5 g / 10 min at 230 ° C., MFR 10.6 g / 10 min at 240 ° C., hereinafter referred to as PP) Oxygen-absorbing resin composition was obtained in the same manner as in Example 1 except that was used. Subsequently, a two-type three-layer film 2 (thickness: 15 μm / 30 μm / 15 μm) was prepared in the same manner as in Example 1 except that the oxygen-absorbing resin composition was used as a core layer and the skin layer was replaced with PP instead of LLDPE2. did. The obtained film had a HAZE of 64%. Urethane vapor-deposited PET (product name: Toppan Printing Co., Ltd.) was used on the corona-treated surface side using urethane-based dry laminate adhesive (product name: “AD-817 / CAT-RT86L-60” manufactured by Toyo Morton Co., Ltd.). “GL-ARH-F”, 12) / adhesive (3) / nylon (product name: “N1202”, 15 manufactured by Toyobo Co., Ltd.) / Adhesive (3) / PP (15) / oxygen absorbing resin An oxygen-absorbing multilayer film of composition (30) / PP (15) was obtained. Using this oxygen-absorbing multilayer film, a 10 × 20 cm three-side sealed bag was prepared, a circular steaming port having a diameter of 2 mm was provided in a part thereof, and the periphery of the steaming port was temporarily attached with a label seal. . The bag was filled with curry containing carrot and meat, sealed, retort cooked at 124 ° C. for 30 minutes, heat sterilized, and stored at 23 ° C. The stew inside the bag was visible. One month later, the bag was heated as it was for about 4 minutes in a microwave oven, and after about 3 minutes, the bag was inflated, the temporarily attached label seal part was peeled off, and it was confirmed that steam was emitted from the steaming port. After cooking, when the flavor of the curry and the color of the carrot were investigated, the appearance of the carrot was kept well, and the flavor of the curry was good.

(Comparative Example 6)
Iron powder having an average particle size of 20 μm and calcium chloride were mixed at a ratio of 100: 1 and kneaded at a weight ratio of LLDPE1 of 30:70 to obtain an iron powder-based oxygen-absorbing resin composition A. The iron powder-based oxygen-absorbing resin composition A was used as a core layer, and an attempt was made to produce a two-layer / three-layer film in the same manner as in Example 1. However, irregularities of the iron powder occurred on the film surface, and no film was obtained. Therefore, an iron powder-based oxygen-absorbing resin composition A was extruded and laminated at a thickness of 20 μm as an oxygen-absorbing layer on LLDPE2 having a thickness of 40 μm, and a laminate film was obtained in which the oxygen-absorbing layer surface was subjected to corona discharge treatment. This laminated film was laminated with bleached kraft paper in the same manner as in Example 13, and bleached kraft paper (basis weight 340 g / m ² ) / urethane-based dry laminating adhesive (product name: “AD-817, manufactured by Toyo Morton Co., Ltd.). / CAT-RT86L-60 ", 3) / Alumina-deposited PET film (Product name:" GL-ARH-F ", Toppan Printing Co., Ltd., 12) / Urethane anchor coating agent (" EL "manufactured by Toyo Morton Co., Ltd.) -557A / B ", 0.5) / low density polyethylene (product name:" Mirason 18SP ", 20) manufactured by Mitsui Chemicals, Inc./iron powder oxygen absorbing resin composition A (20) / LLDPE (40) An attempt was made to produce a gobeltop paper container made of an oxygen-absorbing multilayer paper base material, but it was thick and it was difficult to produce the corners of the paper container. The container production speed was reduced and defective products were finally removed to obtain a container. Thereafter, a preservation test of rice shochu was conducted in the same manner as in Example 13, but an aldehyde odor was generated at the time of opening, and the flavor was remarkably lowered.

(Comparative Example 7)
An iron powder-based oxygen-absorbing resin composition B was obtained in the same manner as in Comparative Example 6 except that PP was used instead of LLDPE1. Similarly, a laminated film of the iron powder-based oxygen-absorbing resin composition B (20) / PP (40) was prepared in the same manner as in Comparative Example 6 except that PP was used instead of LLDPE2, and the oxygen-absorbing layer surface was then corona. Discharge treatment was performed. Thereafter, in the same manner as in Example 14, alumina-deposited PET (product name: “GL-ARH-F”, 12 manufactured by Toppan Printing Co., Ltd.) / Adhesive (3) / nylon (product name: manufactured by Toyobo Co., Ltd.) An oxygen-absorbing multilayer film of “N1202”, 15) / adhesive (3) / iron powder-based oxygen-absorbing resin composition B (20) / PP (40) was obtained. As a result of conducting the same test as in Example 14 using the obtained oxygen-absorbing multilayer film, the flavor was well maintained, but the contents were not visible, and there was bubble-like unevenness on the surface during microwave heating. Occurred.

  As is clear from Examples 13 and 14, the oxygen-absorbing resin composition of the present invention is excellent in processability into a paper container, and can be used for storing an alcoholic beverage or cooking a microwave oven even when a fume throat is attached. It became a good storage container. Moreover, it also has internal visibility, and the color tone of the contents could be confirmed.

  The present invention provides a multilayer body having an oxygen-absorbing resin layer in which a specific polyamide resin, a transition metal, a polyolefin resin, and an epoxy group-containing ethylene copolymer are blended at a specific ratio, thereby reducing oxygen at low humidity and high humidity. The present invention provides an oxygen-absorbing multilayer body that is excellent in absorption performance, retains the resin strength after storage, has excellent workability and interlayer strength, and can be applied to various containers and uses.

Claims (6)

  At least three layers of a sealant layer made of a polyolefin resin, a polyolefin resin, a transition metal catalyst, an oxygen absorbing resin layer containing an epoxy group-containing ethylene copolymer and a polyamide resin, and a gas barrier layer made of a gas barrier material are laminated in this order. The polyamide resin is a polyamide resin having a terminal amino group concentration of 30 μeq / g or less obtained by polycondensation of an aromatic diamine and a dicarboxylic acid, and the oxygen resin in the oxygen absorbing resin layer. The content of the epoxy group-containing ethylene copolymer is 2 to 40% by weight based on the total amount of the oxygen absorbing resin layer, and the total content of the transition metal catalyst and the polyamide resin is based on the total amount of the oxygen absorbing resin layer. An oxygen-absorbing multilayer body characterized by being 15 to 60% by weight.   The oxygen-absorbing multilayer body according to claim 1, wherein adipic acid, sebacic acid, isophthalic acid or a mixture thereof is used as the dicarboxylic acid.   3. The oxygen-absorbing multilayer body according to claim 1, wherein para-xylylenediamine, metaxylylenediamine, or a mixture thereof is used as the aromatic diamine.   The oxygen-absorbing multilayer body according to any one of claims 1 to 3, wherein the transition metal catalyst is cobalt stearate.   5. The molar ratio of the dicarboxylic acid in obtaining the polyamide resin is sebacic acid: adipic acid = 0.3 to 0.7: 0.7 to 0.3. 5. 2. The oxygen-absorbing multilayer body according to 1.   The molar ratio of the dicarboxylic acid when obtaining the polyamide resin is set to adipic acid: isophthalic acid = 0.7 to 0.97: 0.3 to 0.03. 2. The oxygen-absorbing multilayer body according to 1.