JP5601118B2 - Oxygen absorbing multilayer and container - Google Patents

Description

  The present invention provides an oxygen absorbing multilayer body that exhibits excellent oxygen absorption performance, does not have a decrease in strength due to oxidative degradation of the resin, has excellent resin processability, and does not generate odors, and an oxygen absorption formed by thermoforming the multilayer body. The present invention relates to a multilayer container.

  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, which shows an oxidation reaction with a polyamide resin and a transition metal catalyst, but a system in which transition metal is mixed with MXD6 Then, in order to preserve | save an object to be preserve | saved favorably using it as an oxygen absorption resin composition, there existed a case where oxygen absorption capability was 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

  The object of the present invention is to solve the above-mentioned problems, oxygen absorption performance, resin strength, resin processability, appearance, oxygen absorption multilayer body in which contents can be visually recognized, and oxygen absorption formed by thermoforming the multilayer body It is to provide a multilayer container.

  The inventors have blended specific polyamide resin, transition metal and polyolefin resin at a specific ratio, so that the oxygen absorption performance is excellent, the resin strength after storage is maintained, the thermoforming processability is excellent, and the appearance The present inventors have found that an oxygen-absorbing multilayer body that is excellent in content and whose contents can be visually confirmed can be obtained, and that an oxygen-absorbing multilayer container formed by thermoforming the multilayer body has been found.

  That is, the present invention provides an oxygen-absorbing multilayer comprising at least three layers: an oxygen-permeable layer made of a thermoplastic resin, an oxygen-absorbing resin layer containing a polyolefin resin, a transition metal catalyst, and a polyamide resin, and a gas barrier layer made of a gas-barrier substance. 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 transition metal catalyst in the oxygen-absorbing resin layer The oxygen-absorbing multilayer body is characterized in that the total content of the polyamide resin is 15 to 60% by weight based on the total amount of the oxygen-absorbing resin layer.

  The present invention also provides an oxygen-absorbing multilayer container formed by thermoforming the oxygen-permeable multilayer body with the oxygen-permeable layer inside.

  According to the present invention, an oxygen-absorbing multilayer body having high oxygen-absorbing performance, high moldability and transparency, and hardly undergoing strength deterioration due to oxidation of polyamide resin, and an oxygen-absorbing multilayer container formed by thermoforming the multilayer body Can provide.

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

  The thermoplastic resin used in the oxygen permeable layer of the present invention 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 melt flow rate (hereinafter referred to as MFR) of the thermoplastic resin is 1 to 35 g / 10 min at 200 ° C. and 2 to 45 g / 10 min at 240 ° C., considering the processability of the multilayer body. Preferably 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 thermoplastic resin used in the oxygen permeable 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.

In the present invention, the polyolefin resin used in the oxygen-absorbing resin layer includes various polyethylenes such as high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, ultra-low-density polyethylene, and polyethylene using a metallocene catalyst. Polypropylenes such as polystyrene, 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 oxygen-permeable layer in view of the processability of the resin and the adhesion with the oxygen-permeable 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.

  In consideration of the miscibility with the polyamide resin A, it is particularly preferable to add a maleic anhydride-modified polyolefin resin to the oxygen-absorbing resin layer. The addition amount of the maleic anhydride-modified product is preferably 1 to 30 wt%, particularly preferably 3 to 15 wt% with respect to the polyolefin resin.

  The polyolefin resin used in the oxygen-absorbing resin layer of the present invention includes coloring pigments such as titanium oxide, additives such as antioxidants, slip agents, antistatic agents, stabilizers, 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.

  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. 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.

Another method for producing the oxygen-absorbing resin composition of the present invention is preferably a method for producing an oxygen-absorbing resin composition in which a masterbatch containing a polyolefin resin and a transition metal catalyst and a polyamide resin are melt-kneaded.
The transition metal catalyst is kneaded with the polyolefin resin to produce a master batch, and then melt mixed with the polyamide resin A 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 absorption performance of the oxygen-absorbing resin layer is considered to be better when the polyamide resin having the oxygen-absorbing capacity is larger, but surprisingly, the polyamide resin A and the transition metal are mixed with the polyolefin resin, and at a certain ratio. It has been found that when blended, it exhibits 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 for producing the polyamide resin A include orthoxylylenediamine, paraxylylenediamine, and metaxylylenediamine, but paraxylylenediamine and metaxylylenediamine are preferably used from the viewpoint of oxygen absorption performance. Metaxylylenediamine is particularly preferably used. Metaxylylenediamine and paraxylylenediamine may be mixed. Furthermore, 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 include adipic acid, azelaic acid, sebacic acid, dodecanoic acid, isophthalic acid, terephthalic acid, and malonic acid. Among these, adipic acid, sebacic acid, and isophthalic acid are preferably used from the viewpoint of oxygen absorption performance. In addition, various aliphatic dicarboxylic acids and aromatic dicarboxylic acids may be incorporated as copolymerization components as long as they do not affect the performance.

  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 preparing polycondensation by adjusting the molar ratio of aromatic diamine and dicarboxylic acid 2) Method for reacting polyamide resin with carboxylic acid to seal 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 adjusting the molar ratio of aromatic diamine and dicarboxylic acid and carrying out polycondensation, dicarboxylic acid is used in excess 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.

  As the polyamide resin A, a polycondensation product of paraxylylenediamine, metaxylylenediamine and a mixture thereof with a mixture of adipic acid and sebacic acid, or a polycondensation product of a mixture of adipic acid and isophthalic acid is preferably used. . The molar ratio in the case of polycondensation of the diamine, adipic acid and sebacic acid is diamine: sebacic acid: adipic acid = 0.985-0.997: 0.3-0.7: 0.7-0. 3 is preferable, and 0.988 to 0.995: 0.4 to 0.6: 0.6 to 0.4 is particularly preferable. The molar ratio in the case of polycondensation of the diamine, adipic acid and isophthalic acid is diamine: adipic acid: isophthalic acid = 0.985 to 0.997: 0.7 to 0.97: 0.3 to 0.03 is preferable, and 0.988 to 0.995: 0.8 to 0.95: 0.2 to 0.05 is particularly preferable.

  When polyamide resin A and polyolefin resin are mixed, considering the processability, the MFR of polyamide resin A is preferably 3 to 20 g / 10 min at 200 ° C. and 4 to 25 g / 10 min at 240 ° C. It is done. 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 content of the polyamide resin A containing a transition metal catalyst 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. Is particularly preferred. When the content of the polyamide resin A including the transition metal catalyst in the oxygen-absorbing resin layer 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.
The masterbatch used in the present invention may be used and melt-kneaded with the polyolefin resin together with the polyamide resin A to obtain a desired polyamide resin A and a desired transition metal concentration.

  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 oxygen permeable layer is preferably less because the oxygen permeable layer becomes an isolation 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 oxygen permeable layer and the oxygen absorbing resin layer is preferably 1: 0.5 to 1: 3, and preferably 1: 1.5 to 1: 2. 5 is particularly preferred. 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 oxygen permeable layer in view 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 has at least three layers: an oxygen-permeable layer made of a thermoplastic resin, an oxygen-absorbing resin layer containing at least a polyolefin resin, a transition metal catalyst and a polyamide resin A, and a gas barrier layer made of a gas barrier material. Although they are laminated in this order, 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 and the oxygen-absorbing multilayer container of the present invention as a part or all of the sealing packaging container with the oxygen-permeable layer inside, in addition to oxygen that slightly enters from the outside of the container, oxygen in the container It is possible to prevent deterioration of the contents stored in the container due to oxygen.

  Since the oxygen-absorbing multilayer body and oxygen-absorbing multilayer container of the present invention can absorb oxygen regardless of the presence or absence of moisture in the object to be preserved, powder seasonings, powdered coffee, coffee beans, rice, tea, beans, rice cakes It can be suitably used for dried foods such as rice crackers, health foods such as pharmaceuticals and 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 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 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 pellet obtained by melt polymerization by the above method was charged into a rotary tumbler equipped with a heating device, and the inside of the tumbler was depressurized to 1 torr or less while rotating, and then 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-mentioned synthesis conditions using metaxylylenediamine: sebacic acid: adipic acid in a molar ratio of 0.992: 0.4: 0.6. (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 73 ° C., a melting point of 184 ° C., a semicrystallization time of 2000 seconds or more, a terminal amino group concentration of 17.5 μeq / g, a terminal carboxyl group concentration of 91.6 μeq / g, a number average molecular weight of 23500, and an MFR of 240 ° C. It was 11.0 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 0.34cc * 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 200 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 1A). 4040F ”, MFR 4.0 g / 10 min (measured according to JIS K7210), MFR 7.9 g / 10 min at 240 ° C., MFR 8.7 g / 10 min at 250 ° C., hereinafter referred to as LLDPE1), and cobalt stearate Polyamide 1A: LLDPE1 = 40: 60 was melt kneaded at 240 ° C. 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 4.4 g / 10 min at 240 ° C., MFR 5.2 g / 10 min at 250 ° C., hereinafter referred to as LLDPE2), and a two-layer two-layer film 1 (thickness; oxygen-absorbing resin layer) 20 μm / oxygen permeable layer 20 μm) was subjected to corona discharge treatment on the oxygen-absorbing resin layer surface at a width of 800 mm and 100 m / min 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 15%. Nylon film A (product name; manufactured by Toyobo Co., Ltd.) using urethane-type dry laminate adhesive (product name: “TM-319 / CAT-19B” manufactured by Toyo Morton Co., Ltd.) on the corona-treated surface side N1202 ”), aluminum foil and PET film (product name:“ E5102 ”manufactured by Toyobo Co., Ltd.) are laminated, and PET film (12) / adhesive (3) / aluminum foil (9) / adhesive (3) An oxygen-absorbing multilayer film comprising an oxygen-absorbing multilayer body of / nylon film A (15) / adhesive (3) / oxygen-absorbing resin (20) / LLDPE2 (20) was obtained. The numbers in parentheses mean the thickness of each layer (unit: μm). Next, a 15 × 20 cm three-sided sealed bag was produced with the LLDPE 2 layer side as the inner surface, filled with 200 g of a powder seasoning “Dashi no Moto” having a water activity of 0.35, sealed, and stored at 23 ° C. The oxygen concentration in the bag and the flavor of the powder seasoning were examined on the 7th day and after 1 month storage. These results are shown in Table 2.

(Example 2)
An oxygen-absorbing multilayer film was obtained in the same manner as in Example 1 except that the weight ratio during melt-kneading was changed to cobalt stearate-containing polyamide 1A: LLDPE1 = 55: 45. A storage test similar to 1 was conducted. These results are shown in Table 2.

(Example 3)
An oxygen-absorbing multilayer film was obtained 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 1A: LLDPE1 = 25: 75. A storage test similar to 1 was conducted. These results are shown in Table 2.

Example 4
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 0.992: 0.7: 0.3. (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 65 ° C., a melting point of 170 ° C., a semicrystallization time of 2000 seconds or more, a terminal amino group concentration of 19.2 μeq / g, a terminal carboxyl group concentration of 80.0 μeq / g, a number average molecular weight of 25200, and an MFR of 240 ° C. It was 10.1 g / 10 minutes. Moreover, when an unstretched film was produced from the obtained polyamide 2 alone and its oxygen permeability coefficient was determined, it was 0.68 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 200 ppm, and the resulting polyamide 2 and cobalt stearate mixture (hereinafter referred to as cobalt stearate-containing polyamide 2) was added to LLDPE1. Was melt-kneaded at a weight ratio of cobalt stearate-containing polyamide 2: LLDPE1 = 40: 60 at 240 ° C. 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 5)
Polyamide resin was synthesized by performing melt polymerization and solid phase polymerization under the above-described synthesis conditions using metaxylylenediamine: sebacic acid: adipic acid in a molar ratio of 0.992: 0.3: 0.7. (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 78 ° C., a melting point of 194 ° C., a semicrystallization time of 2000 seconds or more, a terminal amino group concentration of 19.5 μeq / g, a terminal carboxyl group concentration of 81.2 μeq / g, a number average molecular weight of 24500, and an MFR of 240 ° C. It was 10.5 g / 10 minutes. Moreover, when the unstretched film was produced with the obtained polyamide 3 simple substance and the oxygen permeability coefficient was calculated | required, it was 0.21cc * mm / (m < ² > * day * atm) (23 degreeC * 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 200 ppm, and LLDPE1 was added to the obtained polyamide 3 and cobalt stearate mixture (hereinafter referred to as cobalt stearate-containing polyamide 3). Was melt-kneaded at a weight ratio of cobalt stearate-containing polyamide 3: LLDPE1 = 40: 60 at 240 ° C. 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 6)
Polyamide resin was synthesized by using metaxylylenediamine: adipic acid in a molar ratio of 0.994: 1 and performing melt polymerization and solid phase polymerization under the above synthesis conditions (hereinafter, the polyamide resin was 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 84 ° C., a melting point of 237 ° C., a half crystallization time of 25 seconds, a terminal amino group concentration of 19.8 μeq / g, a terminal carboxyl group concentration of 67.0 μeq / g, and a number average molecular weight of 23,000. Moreover, since it was near melting | fusing point at 240 degreeC, MFR was not measurable, MFR of 250 degreeC was measured, and MFR in 250 degreeC was 14.4 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 0.09 cc · mm / (m ² · day · atm) (23 ° C. · 60% RH). there were. These results are shown in Table 1.

  Thereafter, addition of cobalt stearate to polyamide 4 and melt-kneading with LLDPE 1 were carried out in the same manner as in Example 1 except that the temperature at the time of melt-kneading was changed to 250 ° C. After obtaining the absorbent 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 7)
Metaxylylenediamine and paraxylylenediamine are mixed at a ratio of 8: 2, 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 the synthesis, 0.2 wt% of phthalic anhydride was added and melt kneaded at 270 ° C. with a twin-screw extruder to seal the terminal amino group (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 270 ° C., and the reaction time was 30 minutes. This polyamide 5 had a Tg of 85 ° C., a melting point of 255 ° C., a semicrystallization time of 24 seconds, a terminal amino group concentration of 23.5 μeq / g, a terminal carboxyl group concentration of 63.2 μeq / g, and a number average molecular weight of 18,900. Moreover, since it was near melting | fusing point at 260 degreeC, MFR was not able to be measured, MFR of 270 degreeC was measured, and MFR in 270 degreeC was 35.7 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.

  Thereafter, addition of cobalt stearate to polyamide 5 and melt-kneading with LLDPE 1 were carried out in the same manner as in Example 1 except that the temperature at the time of melt-kneading was changed to 270 ° C. After obtaining the absorbent 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 8)
Using xylylenediamine: adipic acid: isophthalic acid in a molar ratio of 0.991: 0.9: 0.1, a polyamide resin is synthesized by melt polymerization and solid phase polymerization under the above synthesis conditions. (Hereinafter, the polyamide resin is referred to as polyamide 6). 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 6 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 14.8 μeq / g, a terminal carboxyl group concentration of 67.2 μeq / g, and a number average molecular weight of 23,000. 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 15.4 g / 10min. An unstretched film was prepared from the obtained polyamide 6 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 6 and melt-kneading with LLDPE 1 were carried out in the same manner as in Example 1 except that the temperature during melt-kneading was 250 ° C. After obtaining the absorbent 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 9
An oxygen-absorbing multilayer film was obtained 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 1A: LLDPE1 = 17: 83. A storage test similar to 1 was conducted. These results are shown in Table 2.

(Example 10)
Cobalt stearate was added to LLDPE1 by a side feed to molten LLDPE1 with a twin screw extruder so that the cobalt concentration was 600 ppm. Furthermore, polyamide 1 was melt-kneaded at 240 ° C. in a weight ratio of polyamide 1: cobalt stearate-containing LLDPE1 = 40: 60 to the obtained mixture of LLDPE1 and cobalt stearate to obtain oxygen-absorbing resin pellets.

  Thereafter, after obtaining an oxygen-absorbing multilayer film in the same manner as in Example 1, a three-sided 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)
A film was produced 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 1A: LLDPE1 = 70: 30, and then a three-side sealed bag was produced and stored in the same manner as in Example 1. The test was conducted. These results are shown in Table 2.

(Comparative Example 2)
A film was produced in the same manner as in Example 1 except that it was not melt kneaded with LLDPE1 and the oxygen-absorbing resin layer was made only of cobalt stearate-containing polyamide 1A. A storage test was performed. These results are shown in Table 2.

(Comparative Example 3)
A polyamide resin was synthesized in the same manner as in Example 6 except that metaxylylenediamine: adipic acid was used in a molar ratio of 1: 1 (hereinafter, the polyamide resin is referred to as polyamide 7). Polyamide 7 had a Tg of 84 ° C., a melting point of 237 ° C., a half crystallization time of 25 seconds, a terminal amino group concentration of 42.4 μeq / g, a terminal carboxyl group concentration of 43.5 μeq / g, and a number average molecular weight of 23,300. Moreover, 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 14.1 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, in the same manner as in Example 6, cobalt stearate was added to polyamide 7, melt kneading with LLDPE1, etc., and a film was produced in the same manner as in Example 1. Then, a three-sided sealed bag was produced and carried out. 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 6 except that metaxylylenediamine: adipic acid was used at a molar ratio of 0.994: 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 8). Polyamide 8 had a Tg of 84 ° C., a melting point of 237 ° C., a half crystallization time of 25 seconds, a terminal amino group concentration of 31.4 μeq / g, a terminal carboxyl group concentration of 76.6 μeq / g, and a number average molecular weight of 18,500. Moreover, 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 31.2 g / 10min. An unstretched film was prepared from the obtained polyamide 8 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, in the same manner as in Example 6, the addition of cobalt stearate to polyamide 8 and melt-kneading with LLDPE1, 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.

(Example 11)
Two types of three-layer films (thickness: 10 μm / 20 μm / 10 μm) with oxygen-absorbing resin pellet A as a core layer and LLDPE2 as a skin layer were subjected to corona discharge treatment at a width of 800 mm and 110 m / min. A film roll was prepared.
Alumina-deposited PET film (product name: “GL-” manufactured by Toppan Printing Co., Ltd.) by extrusion lamination using linear low density polyethylene (product name: “Kernel KC580S” manufactured by Nippon Polyethylene Co., Ltd., hereinafter referred to as LLDPE3). ARH-F ”, 12) / laminate adhesive (3) / nylon film A (15) / urethane anchor coating agent (product name:“ A3210 / A3075 ”, 0.5) manufactured by Mitsui Chemicals, Inc./LLDPE3 An oxygen-absorbing multilayer film of (15) / LLDPE2 (10) / oxygen-absorbing resin (20) / LLDPE2 (10) was obtained. When this film was processed into a self-supporting bag (130 × 175 × 35 mm) of two side films and one bottom film with the LLDPE 2 layer side as the inner surface, the bag processability was good. The bag was filled with a total of 200 g together with a solution containing cucumber and acetic acid by high-speed automatic filling at a rate of 40 bags / min. As a result, the bag opening was good and heat sealing could be performed without any problem. 100 filled and sealed bags were boiled at 90 ° C. for 30 minutes, stored at 23 ° C., and the flavor of the cucumbers after 1 month and the appearance of the free-standing bags were examined. The cucumber was visible from the outside of the bag, the flavor and color of the cucumber were well maintained, and there was no abnormality in the appearance of the bag.

(Comparative Example 5)
An oxygen-absorbing resin pellet was prepared 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 1A: LLDPE1 = 80: 20. Similarly, an oxygen-absorbing multilayer film was produced and processed into a self-supporting bag. When 200 g in total was filled together with a solution containing cucumber and acetic acid in the same manner as in Example 11, the sealing strength of the bag was low, and in particular, peeling between the oxygen permeable layer and the oxygen absorbing resin layer occurred. The filled bag was boiled at 90 ° C. for 30 minutes as it was, but 62 bags were broken. When the same storage test as in Example 11 was performed on the remaining bag, the flavor and color tone of the cucumber were lowered. There was no abnormality in the appearance of the bag.

(Comparative Example 6)
Iron powder having an average particle diameter 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-based oxygen-absorbing resin composition A. An iron-based oxygen-absorbing resin composition A was used as a core layer, and an attempt was made to produce a two-kind / three-layer film in the same manner as in Example 11. However, irregularities of iron powder occurred on the film surface, and no film was obtained. Therefore, an iron-based oxygen-absorbing resin is used as an oxygen-absorbing resin layer on a 40 μm-thick linear low-density polyethylene film (product name: “Tosero TUX HC” manufactured by Tosero Co., Ltd., hereinafter referred to as LLDPE4). Composition A was extrusion laminated with a thickness of 20 μm to obtain a laminate film in which the oxygen-absorbing resin layer surface was subjected to corona discharge treatment.
The laminate film was laminated in the same manner as in Example 11, and the alumina-deposited PET film (12) / laminating adhesive (3) / nylon film A (15) / urethane anchor coating agent (0.5) / LLDPE3 (15 ) / Iron-based oxygen-absorbing resin (20) / LLDPE4 (40), an iron-based oxygen-absorbing multilayer film was produced and processed into a self-supporting bag in the same manner as in Example 11.
As in Example 11, when an attempt was made to fill a total of 200 g together with a solution containing cucumber and acetic acid, the bag openability was poor, and the contents spilled out and could not be filled in several bags. Further, after the boil treatment in the same manner as in Example 11, a storage test was conducted. However, since the cucumber was not visible from the outside of the bag, the bag was opened. Although the flavor and color tone of the cucumber were well maintained, the bag had irregularities and some delamination occurred.

(Example 12)
Instead of LLDPE1, an ethylene-propylene random copolymer (product name: “NOVATEC PP FW4BT” manufactured by Nippon Polypro Co., Ltd., MFR 6.5 g / 10 min at 230 ° C., MFR 8.3 g / 10 min at 240 ° C., hereinafter referred to as PP1 Oxygen-absorbing resin pellets B were obtained in the same manner as in Example 1 except that (notation) was used. Oxygen-absorbing resin layer 30 μm made of oxygen-absorbing resin pellet B and olefin polymer alloy (product name: “VMX X150F” manufactured by Mitsubishi Chemical Corporation), MFR 3.5 g / 10 min at 190 ° C., MFR 7.9 g / 10 at 240 ° C. The oxygen permeable layer of 30 μm was laminated to prepare a two-kind two-layer film. Subsequently, using a laminating adhesive, an ethylene-vinyl alcohol copolymer film (product name: “Eval EF-XL” manufactured by Kuraray Co., Ltd.) 15 μm and nylon film B (product name: manufactured by Toyobo Co., Ltd.) N1102 ”) layer 15 μm, nylon film B (15) / laminating adhesive (3) / ethylene-vinyl alcohol copolymer film (15) / laminating adhesive (3) / oxygen absorbing resin (30) / Oxygen-based polymer alloy (30) oxygen-absorbing multilayer film was obtained. The appearance of the film was good.

  Next, an ethylene-propylene random copolymer (product name: “NOVATEC PP EG7F” manufactured by Nippon Polypro Co., Ltd., MFR 1.3 g / 10 min (measured in accordance with JIS K7210), MFR 8.2 g / 10 at 240 ° C. Min., MFR 9.8 g / 10 min at 250 ° C., hereinafter referred to as PP2), PP2 (400) / maleic anhydride modified polypropylene (product name: “Admer QF500”, 15) manufactured by Mitsui Chemicals, Inc./ A sheet of ethylene-vinyl alcohol copolymer A (product name; “Eval L104B”, 40) manufactured by Kuraray Co., Ltd./maleic anhydride-modified polypropylene (product name; same as above, 15) / PP2 (400) was prepared. Was molded into a 70 cc cup with a drawing ratio of 2.5. The cup was filled with orange jelly, and the produced oxygen-absorbing multilayer film was sealed by using it as a cover material with the nylon film B layer side as the outer surface. The color tone of the contents was visible from the lid. The sealed container was heat-treated at 85 ° C. for 30 minutes and stored at 23 ° C. for 1 month. One month later, the container was opened, and it did not become a double lid. The opening was good, and the flavor and color of the contents were well maintained.

(Example 13)
Using an oxygen-absorbing multilayer film obtained in the same manner as in Example 12 and a 70 cc cup, hydrogen peroxide sterilization was performed by immersion. There was no abnormality in the oxygen-absorbing multilayer film during sterilization. The cup was hot-filled with strawberry jam kept at 80 ° C., and the oxygen-absorbing multilayer film was sealed as a lid with the nylon film B layer side outside. The sealed container was stored at 23 ° C. for 1 month. One month later, when the contents were visually confirmed from the lid material, the color tone was kept good. When the lid was opened, the opening was good and the flavor of the contents was well maintained without becoming a double lid.

(Comparative Example 7)
When an iron-based oxygen-absorbing multilayer film having an iron-based oxygen-absorbing resin layer obtained in the same manner as in Comparative Example 6 was sterilized with hydrogen peroxide by the same method as in Example 13, bubbles were generated in hydrogen peroxide, and sterilization was performed. Could not continue.

  As is clear from Examples 1 to 12, the oxygen-absorbing multilayer body of the present invention is excellent in oxygen-absorbing performance, workability and strength, and can be heat-treated, and an oxygen-absorbing multilayer using an iron-based oxygen absorber. It can be applied to foods that cannot be stored by the body, and is a storage container that can be sterilized with hydrogen peroxide. Moreover, it also has internal visibility, can confirm the color tone of the contents, etc., and can also be used for a container lid.

  The present invention provides a multilayer body having an oxygen-absorbing resin layer in which a specific polyamide, a transition metal catalyst and a polyolefin resin are blended at a specific ratio, thereby providing excellent oxygen absorption performance at low humidity and high humidity. The present invention relates to an oxygen-absorbing multilayer body that retains resin strength, has excellent processability, and can be applied to various containers and uses.

(Example 14)
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. Further, PP2 is added as a polyolefin resin to a mixture of the obtained polyamide 1 and cobalt stearate (hereinafter referred to as cobalt stearate-containing polyamide 1B) such that cobalt stearate-containing polyamide 1B: PP2 = 40: 60. Then, the mixture was melt-kneaded at 240 ° C. with a twin-screw extruder to obtain oxygen-absorbing resin pellets C.

  Next, using a four-kind 6-layer multi-layer sheet forming apparatus comprising a first to a fourth extruder, a feed block, a T die, a cooling roll, and a sheet take-up machine, the first extruder; PP2, the second extrusion Said oxygen-absorbing resin pellet C, third extruder; ethylene-vinyl alcohol copolymer B (product name: “Eval L171B” manufactured by Kuraray), and fourth extruder; polypropylene-based adhesive resin (product name: Mitsubishi) Chemical Co., Ltd. “Modic APP P604V”) was extruded to obtain an oxygen-absorbing multilayer sheet. The multilayer sheet is composed of PP2 (80) / oxygen absorbing resin (100) / adhesive layer (15) / ethylene-vinyl alcohol copolymer B (30) / adhesive layer (15) / PP2 (250) from the inner layer. Met. Further, the multilayer sheet obtained by coextrusion was a multilayer sheet having a good appearance without thickness unevenness.

Next, the obtained multilayer sheet was thermoformed into a tray-like container (inner volume 350 cc, surface area 200 cm ² ) with the inner layer inside using a vacuum forming machine. The obtained oxygen-absorbing multilayer container had good appearance with no thickness unevenness. This container was sterilized by ultraviolet sterilization, and 200 g of aseptic cooked rice immediately after cooking was placed in the container, and oxygen in the container was replaced with nitrogen gas to adjust the oxygen concentration to 0.5%. Next, PET film, MXD6 multilayer coextruded nylon film (product name: “Super Neal SP-R” manufactured by Mitsubishi Plastics), unstretched polypropylene film (product name: “Allomer UT21” manufactured by Okamoto Co., Ltd.) Gas barrier film dry-laminated with laminating adhesive (PET film (12) / laminating adhesive (3) / MXD6 multilayer coextruded nylon film (15) / laminating adhesive (3) / unstretched polypropylene film ( 60)) was used as a top film, and after sterilization with ultraviolet rays in the same manner as the container, the container was sealed and stored under conditions of 23 ° C. and 50% RH. The container was opened after measuring the oxygen concentration in the container 3 months after the start of storage, and the flavor of the cooked rice and the strength of the oxygen absorbing container were confirmed. The results are shown in Table 3.

(Example 15)
Except that the weight ratio at the time of melt-kneading was changed to cobalt stearate-containing polyamide 1B: PP2 = 60: 40, an oxygen-absorbing multilayer sheet was obtained in the same manner as in Example 14, and then an oxygen-absorbing multilayer container was prepared and carried out. The same storage test as in Example 14 was performed. The results are shown in Table 3.

(Example 16)
Except that the weight ratio at the time of melt-kneading was changed to cobalt stearate-containing polyamide 1B: PP2 = 25: 75, an oxygen-absorbing multilayer sheet was obtained in the same manner as in Example 14, and then an oxygen-absorbing multilayer container was produced. The same storage test as in Example 14 was performed. The results are shown in Table 3.

(Example 17)
An oxygen-absorbing multilayer sheet was obtained in the same manner as in Example 14 except that polyamide 2 was used in place of polyamide 1, and then an oxygen-absorbing multilayer container was prepared and a storage test similar to that in Example 14 was performed. The results are shown in Table 3.

(Example 18)
Cobalt stearate was added to PP2 to a melted PP2 by side feed with a twin screw extruder so that the cobalt concentration was 600 ppm. Furthermore, polyamide 1 was melt-kneaded at 240 ° C. in a weight ratio of polyamide 1: cobalt stearate containing PP2 = 40: 60 to the obtained mixture of PP2 and cobalt stearate to obtain oxygen-absorbing resin pellets.

  Thereafter, an oxygen-absorbing multilayer sheet was obtained in the same manner as in Example 14, an oxygen-absorbing multilayer container was prepared, and the same storage test as in Example 14 was performed. The results are shown in Table 3.

(Comparative Example 8)
Iron powder having an average particle diameter of 20 μm and calcium chloride were mixed at a ratio of 100: 1, and this and PP2 were kneaded at a weight ratio of 30:70 to obtain an iron-based oxygen-absorbing resin composition B. Subsequently, an iron-based oxygen-absorbing multilayer sheet was produced in the same manner as in Example 14 except that the iron-based oxygen-absorbing resin composition B was used for the oxygen-absorbing resin layer. The multilayer sheet is composed of PP2 (80) / iron-based oxygen absorbing resin B (100) / adhesive layer (15) / ethylene-vinyl alcohol copolymer B (30) / adhesive layer (15) / PP2 from the inner layer. (250). The obtained iron-based oxygen-absorbing multilayer sheet was thermoformed to produce a tray-like container, but it was difficult to process because a drawdown occurred. Moreover, since the produced container used iron powder, it was opaque and the external appearance was bad because of unevenness caused by the iron powder. However, since a container having an appearance was obtained, the same storage test as in Example 14 was performed. The results are shown in Table 3.

(Comparative Example 9)
The oxygen-absorbing multi-layer was formed in the same manner as in Example 14 except that it was not melt-kneaded with PP2, and the oxygen-absorbing resin layer was made of only the cobalt stearate-containing polyamide 1B and used for the oxygen-absorbing resin layer. After obtaining the sheet, an oxygen-absorbing multilayer container was prepared, and the same storage test as in Example 14 was performed. The results are shown in Table 3.

  As is clear from Examples 14-18, the oxygen-absorbing multilayer container of the present invention exhibits good moldability and oxygen-absorbing performance, is transparent, and can retain the strength of the container even after oxygen absorption. is there.

(Example 19)
Two types of three-layer films (thickness: 10 μm / 10 μm / 10 μm) with oxygen-absorbing resin pellet B as the core layer and PP1 as the skin layer were processed by corona discharge treatment on one side at a width of 800 mm and 100 m / min. did. The appearance of the obtained oxygen-absorbing multilayer film was good.

  The oxygen-absorbing multilayer film and a 200 μm polypropylene sheet (product name: “NS3451” manufactured by Sumitomo Bakelite) are dry-laminated using a gas barrier adhesive (product name: “MAXIVE” manufactured by Mitsubishi Gas Chemical Co., Ltd.) After producing an oxygen-absorbing multilayer sheet of PP1 (10) / oxygen-absorbing resin (10) / PP1 (10) / gas barrier adhesive (3) / polypropylene sheet (200) from the inner layer, Vacuum forming with the inner layer on the inside to form a press-through pack pocket (diameter 12 mm, depth 5 mm). In addition, urethane anchor coating agent (product name: “A3210” manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.) is coated on 25 μm aluminum foil, and polypropylene (product name: “F329RA” manufactured by Prime Polymer Co., Ltd.) is used as a heat seal material. Was extruded to a thickness of 25 μm to obtain an aluminum foil laminate of aluminum foil (25) / anchor coating agent (1) / polypropylene (25). The pocket was filled with 2 g of a vitamin C tablet having a water activity of 0.35, the aluminum foil laminate was heat-sealed and sealed, and stored at 23 ° C. When the oxygen concentration in the bag and the appearance after storage for 1 month were investigated, the oxygen concentration in the pocket was 0.1% or less, and the appearance of the vitamin C tablet was well maintained.

(Example 20)
In the same manner as in Example 14, an oxygen-absorbing multilayer sheet was produced. The multilayer sheet is composed of PP2 (90) / oxygen absorbing resin (80) / adhesive layer (15) / ethylene-vinyl alcohol copolymer B (30) / adhesive layer (15) / PP2 (250) from the inner layer. Met. Next, the multilayer sheet was thermoformed into a cup-shaped container (inner volume: 100 cc, surface area: 96 cm ² ) with the inner layer inside, using a vacuum forming machine. After spraying the container with mist of hydrogen peroxide, it was dried with hot air and sterilized. Thereafter, orange jam was filled, and the gas barrier film obtained in the same manner as in Example 14 was similarly sterilized with hydrogen peroxide, sealed using a top film, and stored at 23 ° C. The oxygen concentration in the container after storage for 1 month was 0.1% or less, and the orange jam retained the flavor.

(Comparative Example 10)
In the same manner as in Comparative Example 8, an iron-based oxygen absorbing multilayer sheet was produced. The multilayer sheet is composed of PP2 (90) / iron-based oxygen absorbing resin B layer (80) / adhesive layer (15) / ethylene-vinyl alcohol copolymer B (30) / adhesive layer (15) / from the inner layer. PP2 (250). Next, the iron-based oxygen-absorbing multilayer sheet was thermoformed to try to produce a cup-like container similar to that in Example 20, but it was difficult to process because drawdown occurred. However, since a container having an appearance was obtained, when atomized hydrogen peroxide was sprayed on the container, the iron powder exposed on the container end surface reacted with hydrogen peroxide, and sterilization was difficult. The iron powder on the end face was rusted after drying at.

  The present invention kneads a specific polyamide resin, transition metal and polyolefin resin at a specific ratio, so that the oxygen absorption performance at low humidity and high humidity is excellent, the resin strength after storage is maintained, and the processability is further improved. The present invention relates to an oxygen-absorbing multilayer container that is formed by thermoforming an oxygen-absorbing multilayer body that is excellent in and applicable to various containers and uses.

Claims (4)

An oxygen-absorbing multilayer body comprising at least three layers of an oxygen-permeable layer made of a thermoplastic resin, an oxygen-absorbing resin layer containing a polyolefin resin, a transition metal catalyst, and a polyamide resin, and a gas barrier layer made of a gas-barrier substance, 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 molar ratio at the time of obtaining the polyamide resin is defined as aromatic diamine: sebacic acid: Adipic acid = 0.985 to 0.997: 0.3 to 0.7: 0.7 to 0.3, or aromatic diamine: adipic acid: isophthalic acid = 0.985 to 0.997: 0.7 ～0.97: 0.3 to 0.03 and then, and the total amount of the total content of the transition metal catalyst and the polyamide resin of the oxygen-absorbing resin layer is an oxygen-absorbing resin layer Oxygen absorbing multi-layer body which is a 15 to 60 wt% against. The oxygen-absorbing multilayer body according to claim 1 , wherein paraxylylenediamine, metaxylylenediamine, or a mixture thereof is used as the aromatic diamine. The oxygen-absorbing multilayer body according to claim 1 or 2 , wherein the transition metal catalyst is cobalt stearate. An oxygen-absorbing multilayer container obtained by thermoforming the oxygen-permeable layer of the oxygen-absorbing multilayer body according to any one of claims 1 to 3 inside.