JP4355233B2 - Oxygen absorber and oxygen-absorbing composition and packaging material using the same - Google Patents

Description

  The present invention relates to an oxygen absorbent, an oxygen-absorbing composition using the same, and a packaging material.

In order to stably store articles such as foods that are greatly deteriorated by oxygen, it is important to store them in an environment with little oxygen. In order to enable such storage, various oxygen absorbers have been proposed. As such an oxygen absorbent, an oxygen absorbent using an organic substance containing a carbon-carbon double bond is disclosed (for example, see Patent Documents 1 to 4).
Japanese Patent Laid-Open No. 5-115776 JP-A-9-241635 JP 2000-462 Japanese Patent Laid-Open No. 2000-5596

  However, conventionally proposed oxygen absorbents mainly use polymers as unsaturated compounds, and have a problem of low dispersibility when applied to resin compositions. In addition, the oxygen absorbers that have been proposed in the past have a problem that odor is likely to be generated with the absorption of oxygen.

  In view of such a situation, the present invention has an object to provide an oxygen absorbent that is easy to disperse in a resin and generates less odor due to absorption of oxygen, and an oxygen-absorbing composition using the same. To do.

To achieve the above object, the oxygen absorber of the present invention, seen containing an organic compound having an alicyclic structure containing an unsaturated bond, an oxygen absorption accelerator, wherein the organic compound is 2-methyl-1,3 -Cyclic trimer of butadiene.

  In the oxygen absorbent of the present invention, the oxygen absorption promoter may be at least one selected from the group consisting of a transition metal salt, a radical generator, and a photocatalyst.

The oxygen absorbing composition of the present invention includes a resin, an organic compound and an oxygen absorption promoter that are dispersed in the resin, the organic compound is a compound that have a alicyclic structure containing an unsaturated bond It is a cyclic trimer of 2-methyl-1,3-butadiene .

  In the oxygen-absorbing composition of the present invention, the resin may contain an ethylene-vinyl alcohol copolymer.

  Moreover, the packaging material of this invention contains the part which consists of an oxygen absorptive composition of the said invention.

  Since the molecular weight of the organic compound is small, the oxygen absorbent of the present invention can be easily dispersed in a resin or the like. In addition, the oxygen absorbent according to the present invention hardly releases a low molecular weight compound even when it is oxidized because the unsaturated bond portion to be oxidized forms a cyclic structure. For this reason, the oxygen absorbent of the present invention hardly generates odor even if it absorbs oxygen.

  Embodiments of the present invention will be described below. In addition, although the specific compound is illustrated as a compound which expresses a specific function in the following description, this invention is not limited to this. In addition, the materials exemplified may be used alone or in combination.

(Embodiment 1)
In Embodiment 1, the oxygen absorbent of the present invention will be described. The oxygen absorbent according to Embodiment 1 includes an organic compound having an alicyclic structure containing an unsaturated bond (carbon-carbon double bond) and a molecular weight of 3000 or less (hereinafter sometimes referred to as an organic compound (A)). And an oxygen absorption accelerator. Hereinafter, examples of the organic compound (A) will be described.

There is no limitation in particular in the ratio of an organic compound (A) and an oxygen absorption promoter, and it determines according to the material to be used and the intended purpose. In an example in which a transition metal salt is used as the oxygen absorption accelerator, the amount of the transition metal salt may be in the range of 10 ^{−4 to} 5 parts by weight with respect to 100 parts by weight of the organic compound (A). Moreover, when using a radical generating agent or a photocatalyst as an oxygen absorption accelerator, the amount of the oxygen absorption accelerator may be in the range of 0.1 to 100 parts by weight with respect to 100 parts by weight of the organic compound (A). Good.

  Representative examples of the unsaturated alicyclic hydrocarbon group contained in the organic compound (A) include, for example, a cyclohexenyl group (cyclohexenyl group), a cyclohexenylene group (cyclohexenylene group), a cyclooctenyl group (cycloclotenyl group), A cyclooctenylene group (cyclooctenylene group) is mentioned. In the alicyclic structure, it is preferable that the methylene group adjacent to the unsaturated bond is not substituted. According to such a configuration, high oxygen absorption ability can be obtained, and generation of low molecular compounds due to oxidation of organic compounds can be suppressed.

  The organic compound (A) may be a monocyclic compound containing one cyclic structure or a polycyclic compound containing a plurality of cyclic structures such as bicyclic hydrocarbons and tricyclic hydrocarbons. Good. The number of carbons constituting the ring structure is, for example, in the range of 5-12. A part of hydrogen bonded to carbon constituting the cyclic structure may have halogen, an alkyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. It may be substituted with a substituent such as an alkylaryl group, an alkoxy group, a carboxyl group, an acyl group, or a cyano group. The number of carbon-carbon double bonds contained in the cyclic structure can be selected as long as the cyclic structure does not become an aromatic ring. For example, a 5-membered ring or a 6-membered ring contains 1 or 2 carbon-carbon double bonds. In addition, as long as the organic compound (A) has an alicyclic structure containing an unsaturated bond, it may contain an alicyclic saturated hydrocarbon group or an aromatic hydrocarbon group.

  The organic compound (A) may be a cyclic multimer of a diene compound such as a 1,3-conjugated diene compound (hereinafter sometimes referred to as compound (A1)). The molecular weight of the compound (A1) is usually 3000 or less (for example, 500 or less). Examples of the 1,3-conjugated diene compound include butadiene, isoprene (2-methyl-1,3-butadiene), and chloroprene (2-chloro-1,3-butadiene). Examples of multimers include trimers, tetramers, and pentamers. More specifically, isoprene trimer, tetramer, pentamer and the like can be used as the compound (A1). Among these, it is preferable to use a trimer of isoprene because synthesis is easy.

  The organic compound (A) may contain a hetero atom. When the organic compound (A) contains a hetero atom, the organic compound (A) is easily dispersed in a polymer such as an ethylene-vinyl alcohol copolymer. Examples of the organic compound containing an oxygen atom as a hetero atom include, but are not limited to, at least one selected from acetals, esters, and alkoxysilane derivatives, alcohols, ethers, epoxides, aldehydes, ketones, carboxylic acids, It may be phosphoric acid. Examples of the organic compound containing a sulfur atom as a hetero atom include thioacetal, thioester, thioether, and thiocarboxylic acid. Examples of the organic compound containing a nitrogen atom as a hetero atom include amines, amides, imides, amino acids and the like. Three examples of the organic compound (A) containing an oxygen atom will be described below. In the following examples, the oxygen atom is included in the group bonded to the unsaturated alicyclic structure.

  In the first example, the organic compound (A) is an acetal, that is, a compound containing an acetal structure (hereinafter sometimes referred to as a compound (A2)). The molecular weight of the compound (A2) is usually 3000 or less (for example, 500 or less). When the compound (A2) includes a cyclic acetal structure, an effect of improving the thermal stability of the compound (A2) when dispersed in the resin can be expected.

  Examples of the cyclic acetal structure include a structure included in the formula (2) or the formula (3) described in Examples and a group in which a substituent is added thereto. Examples of the substituent include a hydroxyl group and an alkyl group. When it has a hydroxyl group as a substituent, since it is hard to volatilize, while being able to suppress bleed out from resin, affinity with polar resin improves. Moreover, when it has an alkyl group as a substituent, affinity with nonpolar resin improves. A group containing a cyclic acetal structure is bonded to an alicyclic hydrocarbon containing an unsaturated bond.

  A second example of the organic compound (A) containing an oxygen atom is an ester, that is, a compound containing an ester structure (hereinafter sometimes referred to as compound (A3)). The molecular weight of the compound (A3) is usually 3000 or less (for example, 1500 or less). Compound (A3) contains an unsaturated alicyclic hydrocarbon and an ester structure. For example, the compound (A3) includes an oligomer of an ester containing an unsaturated alicyclic hydrocarbon group.

  A third example of the organic compound (A) containing an oxygen atom is an alkoxysilane derivative, that is, a compound containing an alkoxysilyl group (hereinafter sometimes referred to as compound (A4)). The molecular weight of the compound (A4) is usually 3000 or less (for example, 500 or less). Examples of the alkoxysilyl group include a triethoxysilyl group and a trimethoxysilyl group. The portion other than the alicyclic structure containing an unsaturated bond and the alkoxysilyl group is not particularly limited. For example, halogen, an alkyl group which may have a substituent, and an aryl group which may have a substituent And may contain an atomic group such as an alkylaryl group, alkoxy group, carboxyl group, acyl group or cyano group which may have a substituent.

  The oxygen absorption promoter is an additive for promoting oxygen absorption. Oxidation of the organic compound (A) is promoted by the oxygen absorption promoter, and as a result, oxygen in the atmosphere is consumed. As the oxygen absorption accelerator, for example, at least one selected from the group consisting of an oxidation catalyst (for example, a transition metal salt), a radical generator, and a photocatalyst can be used.

  A transition metal salt can be used for the oxidation catalyst. Examples of the transition metal constituting the salt include iron, nickel, copper, manganese, cobalt, rhodium, titanium, chromium, vanadium, and ruthenium. Among these, iron, nickel, copper, manganese, and cobalt are preferable.

  Examples of the anion constituting the transition metal salt include an anion derived from an organic acid or chloride. Examples of the organic acid include acetic acid, stearic acid, dimethyldithiocarbamic acid, palmitic acid, 2-ethylhexanoic acid, neodecanoic acid, linoleic acid, toluic acid, oleic acid, resin acid, capric acid, and naphthenic acid. . Representative transition metal salts include, for example, cobalt 2-ethylhexanoate, cobalt neodecanoate, cobalt naphthenate, and cobalt stearate. Note that an ionomer may be used as the transition metal salt.

  Examples of the radical generator include N-hydroxysuccinimide, N-hydroxymaleimide, N, N′-dihydroxycyclohexanetetracarboxylic diimide, N-hydroxyphthalimide, N-hydroxytetrachlorophthalimide, N-hydroxytetrabromophthalimide, N-hydroxyhexahydrophthalimide, 3-sulfonyl-N-hydroxyphthalimide, 3-methoxycarbonyl-N-hydroxyphthalimide, 3-methyl-N-hydroxyphthalic acid Imido, 3-hydroxy-N-hydroxyphthalimide, 4-nitro-N-hydroxyphthalimide, 4-chloro-N-hydroxyphthalimide, 4-methoxy-N-hydroxyphthalimide, 4-dimethylamino -N-hydroxyph Luric acid imide, 4-carboxy-N-hydroxyhexahydrophthalic acid imide, 4-methyl-N-hydroxyhexahydrophthalic acid imide, N-hydroxyhetic acid imide, N-hydroxyhymic acid imide, N-hydroxytrimerit Examples include acid imide, N, N-dihydroxypyromellitic acid diimide, N-hydroxysuccinimide, N-hydroxymaleimide, N-hydroxyhexahydrophthalimide, N, N'-dihydroxycyclohexanetetracarboxylic Particularly preferred are acid diimide, N-hydroxyphthalimide, N-hydroxytetrabromophthalimide, and N-hydroxytetrachlorophthalimide.

  Examples of the photocatalyst include titanium dioxide, tungsten oxide, zinc oxide, cerium oxide, strontium titanate, and potassium niobate. These are usually used in the form of a powder. Among these, titanium dioxide is preferable because it has a high photocatalytic function, is recognized as a food additive, and is safe and inexpensive. The titanium dioxide is preferably anatase type, and 30 wt% or more (more preferably 50 wt% or more) of the titanium dioxide powder is preferably anatase type titanium dioxide. By using anatase type titanium dioxide, a high photocatalytic action can be obtained.

  The organic compound (A) and the oxygen absorption accelerator can be mixed in various forms. The mixed form is not particularly limited as long as the oxygen absorbing ability is exhibited. For example, the solvent may be removed after both are dissolved or dispersed in the solvent. It is also possible to use the solution as it is without removing the solvent. In this case, the dispersibility is improved, so that the oxygen absorption ability may be improved. Alternatively, the solvent in the liquid may be removed after applying or impregnating the carrier with the liquid in which both are dissolved or dispersed. As the carrier, for example, a porous carrier can be used, and specifically, silica gel, activated carbon, zeolite and the like can be used. Moreover, you may disperse | distribute both in a polymer | macromolecule.

(Embodiment 2)
In Embodiment 2, the oxygen-absorbing composition of the present invention will be described. The oxygen-absorbing composition of Embodiment 2 includes a resin, an organic compound dispersed in the resin, and an oxygen absorption accelerator. As the organic compound and the oxygen absorption accelerator, the organic compound (A) described in Embodiment 1 and the oxygen absorption accelerator can be used. That is, the composition of Embodiment 2 includes the oxygen absorbent described in Embodiment 1.

The amount of the organic compound (A) and the oxygen absorption accelerator contained in the composition of Embodiment 2 is not particularly limited, and is adjusted according to the material used and the purpose. In an example composition, the amount of the organic compound (A) may be in the range of 1 to 30 parts by weight with respect to 100 parts by weight of the resin. When a transition metal salt is used as the oxygen absorption accelerator, the amount of the transition metal salt may be in the range of 10 ^{−4 to} 5 parts by weight with respect to 100 parts by weight of the organic compound (A). Moreover, when using a radical generating agent or a photocatalyst as an oxygen absorption accelerator, the amount of the oxygen absorption accelerator may be in the range of 0.1 to 100 parts by weight with respect to 100 parts by weight of the organic compound (A). Good.

  The resin is selected according to the use of the composition. Typical resins include synthetic resins such as polyvinyl alcohol resins, polyamide resins, and polyacrylonitrile resins. Since these resins have high oxygen barrier properties, compositions suitable for packaging materials for articles in which deterioration due to oxygen is a problem can be obtained.

  For example, polyolefins such as polyethylene, polypropylene, poly-4-methyl-1-pentene, and poly-1-butene may be used as the resin other than the above. Further, an ethylene-propylene copolymer, polyvinylidene chloride, polyvinyl chloride, polystyrene, polycarbonate, or polyacrylate may be used. Polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate may also be used. Further, a copolymer of ethylene or propylene and another monomer may be used. Other monomers include, for example, α-olefins such as 1-butene, isobutene, 4-methyl-1-pentene, 1-hexene and 1-octene; non-ionic such as itaconic acid, methacrylic acid, acrylic acid and maleic anhydride. Saturated carboxylic acid, salt, partial or complete ester thereof, nitrile, amide, anhydride thereof; vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl octanoate, vinyl dodecanoate, vinyl stearate Carboxylic acid vinyl esters such as vinyl arachidonate; vinyl silane compounds such as vinyl trimethoxysilane; unsaturated sulfonic acids or salts thereof; alkyl thiols; and vinyl pyrrolidones.

  Polyvinyl alcohol resins saponify vinyl ester homopolymers or copolymers of vinyl esters and other monomers (particularly copolymers of vinyl esters and ethylene) using an alkali catalyst or the like. Can be obtained. Examples of the vinyl ester include vinyl acetate, but other fatty acid vinyl esters (vinyl propionate, vinyl pivalate, etc.) may be used.

  The saponification degree of the vinyl ester component of the polyvinyl alcohol resin is preferably 90 mol% or more, for example, 95 mol% or more. By setting the saponification degree to 90 mol% or more, it is possible to suppress a decrease in gas barrier properties under high humidity. Two or more kinds of polyvinyl alcohol resins having different saponification degrees may be used. The degree of saponification of the polyvinyl alcohol resin can be determined by a nuclear magnetic resonance (NMR) method.

  A suitable melt flow rate (MFR) of the polyvinyl alcohol resin (210 ° C. under 2160 g load, based on JIS K7210) is 0.1 to 100 g / 10 minutes, more preferably 0.5 to 50 g / 10 minutes, Preferably it is 1-30 g / 10min. When the melt flow rate is out of the range of 0.1 g to 100 g / 10 minutes, the workability when performing melt molding is often deteriorated.

  Among polyvinyl alcohol-based resins, ethylene-vinyl alcohol copolymer (EVOH) is characterized by being capable of melt molding and having good gas barrier properties under high humidity. The ratio of the ethylene unit to the EVOH structural unit is, for example, in the range of 5 to 60 mol% (preferably 10 to 55 mol%). By setting the proportion of ethylene units to 5 mol% or more, it is possible to suppress a decrease in gas barrier properties under high humidity. Moreover, high gas barrier property is acquired by the ratio of an ethylene unit being 60 mol% or less. The proportion of ethylene units can be determined by a nuclear magnetic resonance (NMR) method. In addition, you may use the mixture of 2 or more types of EVOH from which the ratio of an ethylene unit differs.

  Moreover, as long as the effect of this invention is acquired, EVOH may also contain a small amount of another monomer as a copolymerization component. Examples of such monomers include, for example, α-olefins such as propylene, 1-butene, isobutene, 4-methyl-1-pentene, 1-hexene, 1-octene; itaconic acid, methacrylic acid, acrylic acid Unsaturated carboxylic acids such as maleic anhydride and derivatives thereof; vinylsilane compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (β-methoxy-ethoxy) silane, γ-methacryloxypropyltrimethoxysilane; unsaturated sulfone Examples include acids or salts thereof; alkyl thiols; vinyl pyrrolidones. When EVOH contains 0.0002 to 0.2 mol% of a vinyl silane compound as a copolymerization component, it is easy to produce a homogeneous molded product when molding is performed by coextrusion molding or co-injection molding. As the vinylsilane compound, vinyltrimethoxysilane and vinyltriethoxysilane are preferably used.

  Note that a boron compound may be added to EVOH. This facilitates the production of a homogeneous molded product when molding is performed by coextrusion molding or co-injection molding. Examples of the boron compound include boric acids (for example, orthoboric acid), boric acid esters, borates, and borohydrides. Further, an alkali metal salt (for example, sodium acetate, potassium acetate, sodium phosphate) may be added to EVOH. This may improve interlayer adhesion and compatibility. Further, a phosphate compound (for example, sodium dihydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate, dipotassium hydrogen phosphate) may be added to EVOH. This may improve the thermal stability of EVOH. EVOH to which additives such as a boron compound, an alkali metal salt and a phosphorus compound are added can be produced by a known method.

  The type of polyamide resin is not particularly limited. For example, polycaproamide (nylon-6), polyundecanamide (nylon-11), polylauryllactam (nylon-12), polyhexamethylene adipamide (nylon-6) 6), aliphatic polyamide homopolymers such as polyhexamethylene sebacamide (nylon-6,12); caprolactam / laurolactam copolymer (nylon-6 / 12), caprolactam / aminoundecanoic acid copolymer ( Nylon-6 / 11), caprolactam / ω-aminononanoic acid copolymer (nylon-6 / 9), caprolactam / hexamethylene adipamide copolymer (nylon-6 / 6,6), caprolactam / hexamethylene adipa Mido / hexamethylene sebacamide copolymer (nylon-6 / 6, 6/6, 1 Aliphatic polyamide copolymers such as polymetaxylylene adipamide (MX-nylon), and aromatic polyamides such as hexamethylene terephthalamide / hexamethylene isophthalamide copolymer (nylon-6T / 6I). It is done. These polyamide resins can be used alone or in combination of two or more. Among these, polycaproamide (nylon-6) and polyhexamethylene adipamide (nylon-6, 6) are preferable.

  Examples of the polyacrylonitrile-based resin include a homopolymer of acrylonitrile and a copolymer of a monomer such as an acrylate ester and acrylonitrile.

  As long as the effect of the present invention is obtained, the composition of Embodiment 2 is an antioxidant, a plasticizer, a heat stabilizer (melting stabilizer), a photoinitiator, a deodorant, an ultraviolet absorber, an antistatic agent, a lubricant, At least one of additives such as a colorant, a filler, a filler, a pigment, a dye, a processing aid, a flame retardant, an antifogging agent, and a drying agent may be included.

  As the heat stabilizer (melt stabilizer), for example, one or more of a hydrotalcite compound and a metal salt of a higher aliphatic carboxylic acid (for example, calcium stearate or magnesium stearate) can be used. By using these compounds, it is possible to prevent the formation of gels and fish eyes during the production of the composition.

  When the oxygen absorbent of the present invention is used, the generation of odor accompanying oxygen absorption is greatly reduced. However, particularly when the composition is used as a packaging material for articles in which odor is a problem, the composition of the present invention may contain a deodorizing agent in order to further suppress the generation of odor.

  Examples of the deodorizer include zinc compounds, aluminum compounds, silicon compounds, iron (II) compounds, and organic acids.

  The composition of the present invention can be formed by mixing components such as an oxygen absorbent (that is, an organic compound (A) and an oxygen absorption accelerator), a resin, and an additive. The method of mixing each component and the order of mixing are not particularly limited. For example, all the components may be mixed simultaneously. Moreover, you may mix with resin, after mixing an organic compound (A), an oxygen absorption promoter, and an additive. Moreover, after mixing an organic compound (A) and an additive, you may mix with an oxygen absorption promoter and resin. Moreover, you may mix with an organic compound (A) and an additive, after mixing an oxygen absorption promoter and resin. Moreover, after mixing an organic compound (A), resin, and an additive, you may mix with an oxygen absorption promoter. Moreover, you may mix with an organic compound (A) and resin, after mixing an oxygen absorption promoter and an additive. Moreover, you may mix the mixture obtained by mixing an organic compound (A), resin, and an additive, and the mixture obtained by mixing an oxygen absorption promoter and resin.

  Specific methods for mixing include, for example, a method in which each component is dissolved in a solvent to prepare a plurality of solutions, and after these solutions are mixed, the solvent is evaporated, or other components are added to the molten resin. And kneading.

  The kneading can be performed using, for example, a ribbon blender, a high-speed mixer, a kneader, a mixing roll, an extruder, or an intensive mixer.

  The composition of the present invention can be formed into various forms, for example, films, sheets, containers and the like. These molded products can be used as packaging materials and oxygen scavengers. The composition of the present invention may be once molded into pellets, or may be directly molded by dry blending each component of the composition.

(Embodiment 3)
In Embodiment 3, the packaging material of the present invention will be described. The packaging material of the present invention includes a layer made of the oxygen-absorbing composition described in the second embodiment. This packaging material can be formed by processing the composition of Embodiment 2 into various shapes.

  The composition of Embodiment 2 may be formed into a shape such as a film, a sheet, and a pipe by, for example, a melt extrusion method. Moreover, you may shape | mold into a container shape by the injection molding method. Moreover, you may shape | mold into hollow containers, such as a bottle, by a hollow molding method. As the hollow molding, for example, extrusion hollow molding or injection hollow molding can be applied.

  The packaging material of Embodiment 3 may be composed of only a layer made of the composition of Embodiment 2 (hereinafter sometimes referred to as layer (A)), but a layer made of another material (hereinafter referred to as layer (B). ) In some cases). By setting it as a laminated body, characteristics, such as a mechanical characteristic, water vapor | steam barrier property, and oxygen barrier property, can further be improved. The material and number of layers (B) are selected according to the properties required for the packaging material.

  The structure of the laminated body is not particularly limited. Between the layer (A) and the layer (B), an adhesive resin layer (hereinafter sometimes referred to as a layer (C)) for bonding them may be disposed. The structure of the laminate is, for example, layer (A) / layer (B), layer (B) / layer (A) / layer (B), layer (A) / layer (C) / layer (B), layer ( B) / layer (C) / layer (A) / layer (C) / layer (B), layer (B) / layer (A) / layer (B) / layer (A) / layer (B), and layer (B) / layer (C) / layer (A) / layer (C) / layer (B) / layer (C) / layer (A) / layer (C) / layer (B). When the laminate includes a plurality of layers (B), they may be the same or different. The thickness of each layer of the laminate is not particularly limited. By setting the ratio of the thickness of the layer (A) to the thickness of the entire laminate in the range of 2 to 20%, it may be advantageous in terms of moldability and cost.

  The layer (B) can be formed of, for example, a thermoplastic resin or a metal. Examples of the metal used for the layer (B) include steel and aluminum. Although the thermoplastic resin used for a layer (B) is not specifically limited, For example, resin illustrated about the layer (A) can be used. For example, polyolefins such as polyethylene, polypropylene, poly-4-methyl-1-pentene, and poly-1-butene may be used. Further, an ethylene-propylene copolymer, polyvinylidene chloride, polyvinyl chloride, polystyrene, polyacrylonitrile, polycarbonate, polyacrylate, or ethylene-vinyl alcohol copolymer may be used. Polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate may also be used. Polyamides such as polycaproamide, polyhexamethylene adipamide, and polymetaxylylene adipamide may also be used. Further, a copolymer of ethylene or propylene and another monomer may be used. Other monomers include, for example, α-olefins such as 1-butene, isobutene, 4-methyl-1-pentene, 1-hexene and 1-octene; non-ionic such as itaconic acid, methacrylic acid, acrylic acid and maleic anhydride. Saturated carboxylic acid, salt, partial or complete ester thereof, nitrile, amide, anhydride thereof; vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl octanoate, vinyl dodecanoate, vinyl stearate Carboxylic acid vinyl esters such as vinyl arachidonate; vinyl silane compounds such as vinyl trimethoxysilane; unsaturated sulfonic acids or salts thereof; alkyl thiols; and vinyl pyrrolidones.

  The layer (A) and the layer (B) may be unstretched, or may be stretched or rolled uniaxially or biaxially.

  The adhesive resin used for the layer (C) is not particularly limited as long as it can bond the respective layers. For example, polyurethane-based, polyester-based one-pack or two-pack curable adhesive, unsaturated carboxylic acid or its anhydride (maleic anhydride, etc.) copolymerized or graft-modified into an olefin polymer (carboxylic acid modified) Polyolefin resin). When the layer (A) and the layer (B) contain a polyolefin resin, high adhesion can be realized by using a carboxylic acid-modified polyolefin resin. Examples of the carboxylic acid-modified polyolefin resin can be obtained by modifying a polymer such as polyethylene, polypropylene, copolymer polypropylene, ethylene-vinyl acetate copolymer, and ethylene- (meth) acrylate ester copolymer with carboxylic acid. Resin.

  You may mix | blend a deodorizing agent with at least 1 layer of the layer which comprises a laminated body. As the deodorizer, for example, the deodorizer exemplified in Embodiment 2 can be used.

  The manufacturing method of the laminated body of Embodiment 3 is not specifically limited, For example, it can form by a well-known method. For example, methods such as an extrusion lamination method, a dry lamination method, a solvent casting method, a co-injection molding method, and a co-extrusion molding method can be applied. As the coextrusion molding method, for example, a coextrusion lamination method, a coextrusion sheet molding method, a coextrusion inflation molding method, and a coextrusion blow molding method can be applied.

  When the packaging material of the present invention is a container having a multilayer structure, oxygen in the container is rapidly absorbed by disposing the layer made of the composition of Embodiment 2 in a layer close to the inner surface of the container, for example, the innermost layer. It becomes possible.

  Among the multilayer containers, the present invention is suitably used for multilayer containers having a total thickness of 300 μm or less, or multilayer containers manufactured by an extrusion blow molding method.

  A multilayer container having a total thickness of 300 μm or less is a container composed of a relatively thin multilayer structure such as a multilayer film, and is usually used in the form of a pouch or the like. Since it is flexible and easy to manufacture, has excellent gas barrier properties, and has a continuous oxygen absorption function, it is extremely useful for packaging products that are sensitive to oxygen and easily deteriorate. By setting the total layer thickness to 300 μm or less, high flexibility can be obtained. By setting the thickness of all layers to 250 μm or less, particularly 200 μm or less, higher flexibility can be obtained. In consideration of mechanical strength, the total layer thickness is preferably 10 μm or more, and more preferably 20 μm or more.

  In order to seal such a multilayer container, it is preferable that at least one surface layer of the multilayer film is a layer made of a heat-sealable resin. Examples of such a resin include polyolefin such as polyethylene and polypropylene. A multilayer container is obtained by filling the multilayer film processed into a bag shape with the contents and heat-sealing.

  On the other hand, the multilayer container manufactured by the extrusion blow molding method is usually used in the form of a bottle or the like. Since it has high productivity and excellent gas barrier properties and has a continuous oxygen absorption function, it is extremely useful for packaging products that are highly sensitive to oxygen and easily deteriorated.

  The thickness of the body of the bottle-type container is generally in the range of 100 to 2000 μm, and is selected according to the application. In this case, the thickness of the layer formed of the composition of Embodiment 2 can be set in the range of 2 to 200 μm, for example.

  The packaging material of the present invention may be a packing for a container (gasket), particularly a gasket for a container cap. In this case, a gasket is formed by the composition of Embodiment 2.

  Hereinafter, the present invention will be described in more detail with reference to examples.

  In Example 1, the oxygen absorption ability of a cyclic trimer of 2-methyl-1,3-butadiene (hereinafter sometimes referred to as IP trimer) was measured.

  An IP trimer was produced by the following method. First, 2 mmol of nickel tetracarbonyl, 2 mmol of tri-n-butylarsenic, and 20 mL (0.2 mol) of 2-methyl-1,3-butadiene were mixed and stirred at room temperature. After the generation of carbon monoxide stopped, 10 mmol of trimethylaluminum and 50 mL (0.5 mol) of 2-methyl-1,3-butadiene were added, and the reaction vessel was sealed and reacted at 80 ° C. for 12 hours, and then cooled. did. The resulting reaction mixture was extracted with ether with hydrochloric acid, washed with water, concentrated and distilled. In this way, an IP trimer represented by the formula (1) was obtained.

  Next, an oxygen absorbent was produced by the following method. First, in a nitrogen atmosphere, 1 g of IP trimer was dissolved in degassed hexane, and cobalt naphthenate was added so as to be 800 ppm in terms of metal. Next, hexane was distilled off. In this way, an oxygen absorbent was obtained. 0.1 g of this oxygen absorbent was placed in a bottle of 260 cc in a 50% RH room at 23 ° C., and the bottle was capped. This bottle was stored in a room at 23 ° C., and the oxygen absorption rate of the oxygen absorbent was measured by measuring the oxygen concentration in the bottle after a certain period of time.

  Further, as a comparative example, the same evaluation was performed by using polybutadiene manufactured by Aldrich instead of IP trimer.

  FIG. 1 shows the measurement results of IP trimer and polybutadiene. As is clear from FIG. 1, the IP trimer showed a good oxygen absorption capacity.

  In Example 2, the oxygen absorbing ability of an oxygen absorbent using a compound containing a cyclic acetal structure and an ester oligomer was measured.

  As a compound containing a cyclic acetal structure, a mixture of compounds represented by the following formulas (2) and (3) was used.

  Further, as the ester oligomer, those represented by the following formula (4) and those represented by the following formula (5) were used.

  The acetal compounds represented by the formulas (2) and (3) were produced by the following method. First, in a 3-neck flask having an internal volume of 100 mL, 55 mL of toluene, 22.0 g (0.2 mol) of 3-cyclohexenecarboxaldehyde, 18.4 g (0.2 mol) of glycerol, and 0.1 g of p-toluenesulfonic acid. Was allowed to react at 120 ° C. for 2 hours while removing generated water. The reaction was stopped when 3.6 g of water was separated, and the reaction mixture was cooled to room temperature. The reaction mixture was neutralized with 25% aqueous ammonia, and 25 mL of water was added to separate the organic layer. The obtained organic layer was washed successively with 25 mL of water and 25 mL of saturated brine, and then dried by adding anhydrous sodium sulfate. Next, toluene was distilled off under reduced pressure, followed by distillation under reduced pressure to obtain 22.1 g of the desired mixture of acetal compounds.

  The oligomer represented by Formula (4) was produced by the following method. First, 100 g of toluene, 14.2 g (0.1 mol) of 5-cyclohexene-1,1-dimethanol, 17.0 g (0.1 mol) of 4,5-dihydrotetrahydrophthalic acid were added to a three-necked flask having an internal volume of 300 mL. ) And 0.1 g of p-toluenesulfonic acid, and reacted at 120 ° C. for 6 hours while removing the water produced. The reaction was stopped when 1.9 g of water was separated, and the reaction mixture was cooled to room temperature. The reaction mixture was washed 3 times with 100 mL of water, and then toluene was distilled off under reduced pressure. In this way, 31.1 g of an oligomer represented by the formula (4) having a molecular weight of about 1500 was obtained.

  As the oligomer represented by the formula (5), instead of 14.2 g of 5-cyclohexene-1,1-dimethanol, 14.2 g (0.1 mol) of 5-cyclooctene-1,2-diol was used. Except this, it was prepared in the same manner as the oligomer of formula (4). In this way, 32.7 g of an oligomer represented by the formula (5) having a molecular weight of about 1500 was obtained.

  Next, an oxygen absorbent was produced by the following method. First, 1 g of the mixture of the acetal compounds or 1 g of the ester oligomer was dissolved in degassed toluene under a nitrogen atmosphere, and cobalt naphthenate was added so as to be 800 ppm in terms of metal. Next, toluene was distilled off. In this way, three types of oxygen absorbents were obtained. Three types of oxygen absorbents were obtained in the same manner except that N-hydroxyphthalimide (NHPI), which is a radical generator, was used instead of cobalt naphthenate. Furthermore, regarding the mixture of the acetal compound represented by the above formula (2) and the acetal compound represented by the formula (3), titanium dioxide powder (P-25, manufactured by Nippon Aerosil Co., Ltd.) instead of cobalt naphthenate. ) Was used in the same manner except that 1 and 10% by weight were used.

  0.1 g of these oxygen absorbents were put in a bottle of 260 cc in a 50% RH room at 23 ° C. and capped. When cobalt naphthenate and NHPI are used as the oxygen absorption accelerator, the bottle is stored in a thermostatic bath at 60 ° C., and the oxygen concentration in the bottle is measured after 7 days. Absorption was measured. When titanium dioxide is used as the oxygen absorption accelerator, this bottle is stored at 23 ° C. under a fluorescent lamp, and the oxygen absorption amount of the oxygen absorbent is determined by measuring the oxygen concentration in the bottle after 7 days. It was measured. The measurement results are shown in Table 1.

  In addition, the saturated oxygen absorption amount shown in Table 1 does not indicate the maximum oxygen absorption amount of the compounds of the formulas (2) to (5). By improving the dispersibility in the oxygen absorbent, the compounds of the formulas (2) to (5) exhibit higher oxygen absorption ability. For example, when the acetal mixture of formulas (2) and (3) and cobalt naphthenate were adsorbed on silica gel and the amount of saturated oxygen absorbed was measured, a value of 130 cc / g was obtained.

  In Example 3, the oxygen absorbent was measured by dispersing the oxygen absorbent in EVOH. For the measurement, a mixture of an acetal compound represented by the above formula (2) and an acetal compound represented by the formula (3), an ester compound represented by the above formula (5), and the following formula (6) A mixture of a compound represented by formula (7) and a compound represented by formula (8) below and a compound represented by formula (9) were used.

  A mixture of the compounds represented by formulas (6) and (7) was used except that 27.6 g (0.2 mol) of cyclooctenecarboxaldehyde was used instead of 22.0 g of 3-cyclohexenecarboxaldehyde. A mixture of compounds represented by formulas (2) and (3) was made in the same manner.

  A mixture of the compounds represented by formulas (8) and (9) is used except that 32.4 g (0.2 mol) of tricyclodecene carboxaldehyde is used instead of 22.0 g of 3-cyclohexene carboxaldehyde. These were prepared in the same manner as the method for producing the mixture of compounds represented by formulas (2) and (3).

  Next, the sheet | seat containing an oxygen absorbent composition was produced with the following method. First, in a nitrogen atmosphere, cobalt stearate was added to EVOH melted at 200 ° C. at a rate of 800 ppm in terms of metal, and the mixture was stirred and dispersed for 2 minutes. To this, the above compound was added at a ratio of 10% by weight and dispersed by stirring for 5 minutes.

  The oxygen absorbent-containing EVOH thus obtained was pressed into a sheet at 180 ° C. for 2 minutes. And the obtained sheet | seat was cut so that the mass might be set to 0.5g. In this way, four types of sheets containing the oxygen absorbent composition were produced. For comparison, a sheet made of only EVOH was produced by the above press working.

  Next, one sheet (0.5 g) was placed in a bottle with a capacity of 260 cc in a 50% RH room at 23 ° C. and capped. This bottle was stored in a constant temperature bath at 23 ° C., and the oxygen absorption rate of the oxygen-absorbing composition was measured by measuring the oxygen concentration in the bottle after a certain period of time. The measurement results are shown in FIG. In addition, the sheet | seat which consists only of EVOH showed almost no oxygen absorption during the test period.

  In Example 4, the generation of odor accompanying oxygen absorption was evaluated for the oxygen absorbent. In Example 4, evaluation was performed on a mixture of IP trimers and acetal compounds represented by formulas (2) and (3). Further, as a comparative example, the same evaluation was performed using polybutadiene and linolenic acid.

  An oxygen absorbent containing IP trimer and an oxygen absorbent containing polybutadiene were prepared in the same manner as in Example 1. An oxygen absorbent containing a mixture of acetal compounds was prepared in the same manner as in Example 2. An oxygen absorbent containing linolenic acid was produced in the same manner as in Example 1.

  The oxygen absorbent using polybutadiene and IP trimer was put into a bottle and stored at 60 degrees for 11 days, and the presence or absence of odor generation was evaluated. Moreover, about the oxygen absorbent using the mixture of an acetal compound and linolenic acid, it put into the bottle and stored at 23 degreeC for 14 days, and the presence or absence of generation | occurrence | production of an odor was evaluated. As a result, the oxygen absorbent using the IP trimer and the acetal compound had almost no odor. On the other hand, the oxygen absorbent using polybutadiene has a specific odor derived from the raw material and a burnt odor due to oxidative degradation. In addition, the oxygen absorbent using linolenic acid had a severe fishy odor.

  As mentioned above, although this invention was demonstrated, this invention is not limited to the said embodiment, Based on the technical idea of this invention, it can apply to other embodiment.

  The present invention can be applied to oxygen absorbers, oxygen-absorbing compositions, and packaging materials using them. In particular, it is suitably used as a packaging material for articles, such as foods, medicines, medical equipment, machine parts, and clothing, which are greatly affected by deterioration due to oxygen.

It is a graph which shows an example of oxygen absorption ability about the oxygen absorbent of this invention and the oxygen absorbent of a comparative example. It is a graph which shows an example of oxygen absorption ability about the sheet | seat containing the oxygen absorbent composition of this invention.

Claims (5)

An organic compound having an alicyclic structure containing an unsaturated bond, an oxygen absorption accelerator seen including,
An oxygen absorbent, wherein the organic compound is a cyclic trimer of 2-methyl-1,3-butadiene . The oxygen absorbent according to claim 1, wherein the oxygen absorption accelerator is at least one selected from the group consisting of a transition metal salt, a radical generator, and a photocatalyst. A resin, an organic compound and an oxygen absorption accelerator dispersed in the resin,
The organic compound is a compound which have a alicyclic structure containing an unsaturated bond, an oxygen absorbing composition which is a cyclic trimer of 2-methyl-1,3-butadiene. The oxygen-absorbing composition according to claim 3, wherein the resin contains an ethylene-vinyl alcohol copolymer. A packaging material comprising a portion made of the oxygen-absorbing composition according to claim 3 or 4 .