JP4926697B2 - Oxygen absorbent, method for producing the same, and oxygen-absorbing composition and packaging material using the same - Google Patents

Description

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

  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 oxygen absorbers, oxygen absorbers in which an organic compound is supported on an inorganic substance are disclosed (for example, JP-A-11-278845, JP-A-2000-462, JP-A-2000-5596). JP, 2000-86415, JP, 2002-320917, A).

  However, oxygen absorbers that have been proposed in the past have a problem in that the performance is greatly lowered when dispersed in a resin.

  In view of such circumstances, the present invention provides an oxygen absorbent capable of constituting a resin composition having a high oxygen absorption capacity, a method for producing the same, and an oxygen-absorbing resin composition and a packaging material using the same. One of the purposes.

  In order to achieve the above object, the oxygen absorbent of the present invention includes inorganic particles, an organic compound (organic group) chemically adsorbed on the inorganic particles, and an oxygen absorption accelerator.

  In the oxygen absorbent of the present invention, the organic compound is formed by reacting at least one organic compound (A) selected from the group consisting of carboxylic acid, ester, aldehyde, alkoxysilane derivative and amine with the inorganic particles. Organic compounds may be used.

  In the oxygen absorbent of the present invention, the organic compound may be an unsaturated organic compound.

  In the oxygen absorbent of the present invention, the organic compound may include a structure represented by the following formula (1).

[Wherein, R ¹ and R ² are each independently a hydrogen atom, an alkyl group, an alkyl group having a substituent, an aryl group, an aryl group having a substituent, an alkylaryl group, an alkylaryl group having a substituent, It is one selected from —COOR ³ , —OCOR ³ , a cyano group and a halogen atom. R ³ is one selected from an alkyl group, an alkyl group having a substituent, an aryl group, an aryl group having a substituent, an alkylaryl group, and an alkylaryl group having a substituent. ]

  In the oxygen absorbent of the present invention, the organic compound may include a structure represented by the following formula (2).

[Wherein, R ⁴ and R ⁵ each independently represents a hydrogen atom, an alkyl group, an alkyl group having a substituent, an aryl group, an aryl group having a substituent, an alkylaryl group, an alkylaryl group having a substituent, It is one selected from —COOR ³ , —OCOR ³ , a cyano group and a halogen atom. R ³ is one selected from an alkyl group, an alkyl group having a substituent, an aryl group, an aryl group having a substituent, an alkylaryl group, and an alkylaryl group having a substituent. ]

  In the oxygen absorbent of the present invention, the organic compound may have an unsaturated alicyclic structure.

  In the oxygen absorbent of the present invention, the formula amount of the organic compound may be 3000 or less.

  In the oxygen absorbent of the present invention, the inorganic particles may be composed of a layered inorganic compound.

  In the oxygen absorbent according to the present invention, the inorganic particles may have a hydroxyl group on the surface. In this case, the inorganic particles may be hydrotalcite particles.

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

  The production method of the present invention is a production method of an oxygen absorbent containing inorganic particles and an oxygen absorption accelerator, and includes a step of chemically adsorbing an organic compound to the inorganic particles.

  In the production method of the present invention, the organic compound may be an unsaturated organic compound.

  In the production method of the present invention, the inorganic particles may have a hydroxyl group on the surface, and the organic compound may have a functional group that reacts with the hydroxyl group.

  In the production method of the present invention, the organic compound may be at least one organic compound selected from the group consisting of carboxylic acids, esters, aldehydes, alkoxysilane derivatives, and amines.

  The production method of the present invention may include (i) a step of preparing a mixture containing the organic compound, the inorganic particles, and an organic solvent, and (ii) a step of removing the organic solvent from the mixture. In this case, a step of heating the mixture at a temperature equal to or higher than the boiling point of water may be included after the step (ii).

  The production method of the present invention includes (I) a step of preparing a mixture containing the organic compound and the inorganic particles, and (II) a step of chemically adsorbing the organic compound to the inorganic particles by heating the mixture. And may be included. In this case, the step (II) may include a step of heating the mixture at a temperature equal to or higher than the boiling point of water.

  In the production method of the present invention, the mixture may be heated under a nitrogen atmosphere or under reduced pressure.

  In the production method of the present invention, the inorganic particles may be composed of a layered inorganic compound.

  Another oxygen absorbent of the present invention is an oxygen absorbent produced by the production method of the present invention.

  The oxygen-absorbing composition of the present invention is an oxygen-absorbing composition comprising a resin and an oxygen absorbent dispersed in the resin, and the oxygen absorbent is the oxygen absorbent of the present invention.

  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 oxygen absorbent of the present invention is in the form of particles, it can be easily dispersed uniformly in the resin. Moreover, since the organic compound to be oxidized is chemically adsorbed on the inorganic particles, the oxygen absorbent of the present invention exhibits high oxygen absorption ability.

  Moreover, according to the production method of the present invention, an oxygen absorbent in which an organic compound to be oxidized is chemically adsorbed on inorganic particles can be easily obtained.

  Moreover, since the oxygen-absorbing resin composition of the present invention uses the oxygen absorbent of the present invention, the oxygen-absorbing resin composition exhibits high oxygen absorption ability and can suppress the occurrence of bleed out. In addition, when the oxygen absorbent is blended with the resin, the organic compound to be oxidized can be prevented from volatilizing from the vent. Further, even when the oxygen absorbent is washed before blending the oxygen absorbent with the resin, it is possible to prevent the organic compound to be oxidized from being removed. By using such a resin composition, a packaging material having high oxygen absorption ability, excellent moldability, and high food hygiene safety can be obtained. Further, by using such a packaging material, oxygen inside the package formed using the packaging material can be reduced.

FIG. 1 is a graph showing an example of the oxygen absorption capacity of the oxygen absorbents of the present invention and comparative examples. FIG. 2 is a diagram showing an example of an infrared absorption spectrum of the oxygen absorbent according to the present invention. FIG. 3 is a graph showing an example of the oxygen absorption capacity of the oxygen absorbent according to the present invention. FIG. 4 is a graph showing another example of the oxygen absorption capacity of the oxygen absorbent according to the present invention. FIG. 5 is a graph showing another example of the oxygen absorption capacity of the oxygen absorbent according to the present invention. FIG. 6 is a graph showing an example of oxygen absorption capacity for a press film made of the oxygen-absorbing composition of the present invention.

  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 unless otherwise specified.

(Embodiment 1)
In Embodiment 1, the oxygen absorbent of the present invention will be described. The oxygen absorbent of the present invention includes inorganic particles, an organic compound (organic group) chemically adsorbed on the inorganic particles, and an oxygen absorption accelerator. The organic compound is an unsaturated organic compound containing a carbon-carbon double bond when a transition metal salt or a radical generator is used as an oxygen absorption accelerator. In that case, 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. As such a configuration, for example, the organic compound may include a structure represented by the following formula (1) or (2).

[Wherein, R ¹ and R ² are each independently a hydrogen atom, an alkyl group, an alkyl group having a substituent, an aryl group, an aryl group having a substituent, an alkylaryl group, an alkylaryl group having a substituent, It is one selected from —COOR ³ , —OCOR ³ , a cyano group and a halogen atom. R ³ is one selected from an alkyl group, an alkyl group having a substituent, an aryl group, an aryl group having a substituent, an alkylaryl group, and an alkylaryl group having a substituent. ]

[Wherein, R ⁴ and R ⁵ each independently represents a hydrogen atom, an alkyl group, an alkyl group having a substituent, an aryl group, an aryl group having a substituent, an alkylaryl group, an alkylaryl group having a substituent, It is one selected from —COOR ³ , —OCOR ³ , a cyano group and a halogen atom. R ³ is one selected from an alkyl group, an alkyl group having a substituent, an aryl group, an aryl group having a substituent, an alkylaryl group, and an alkylaryl group having a substituent. ]
When R1, R2, R3, R4 and R5 are an alkyl group having a substituent, an aryl group having a substituent, or an alkylaryl group having a substituent, the substituent improves affinity with the resin. Are preferable, and examples thereof include a hydroxyl group and an alkoxy group having 1 to 10 carbon atoms.

The organic compound that is chemically adsorbed on the inorganic particles reacts with the organic compound having a functional group that reacts with the surface of the inorganic particles (hereinafter sometimes referred to as organic compound (A)) and the surface of the inorganic particles. It is formed. The ratio of the inorganic particles, the organic compound (A) chemically adsorbed to the inorganic particles, and the oxygen absorption accelerator is not particularly limited, and is determined according to the material used and the purpose of use. In one example, the amount of the organic compound (A) adsorbed to 100 parts by weight of the inorganic particles is in the range of 1 to 100 parts by weight, preferably in the range of 1 to 50 parts by weight. Moreover, when using a transition metal salt as an oxygen absorption promoter, 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.

  There is no limitation in particular in the average particle diameter of an inorganic particle, For example, it is 1000 nm or less, Preferably it is 500 nm or less. By setting the average particle size of the inorganic particles to 1000 nm or less, the organic compound (A) can be efficiently chemically adsorbed by increasing the surface area. Moreover, the dispersibility to resin can be improved and transparency can be provided.

  The inorganic particles preferably have a reactive functional group on the surface, and particularly preferably have a hydroxyl group on the surface. The inorganic particles are preferably made of a layered inorganic compound. Examples of the layered compound include layered double hydroxides such as hydrotalcite, layered clay minerals such as montmorillonite and kaolinite, layered silicates such as canemanite, layered metal phosphate, and layered copper hydroxide. . An oxygen-absorbing composition and a packaging material having a high gas barrier property can be produced by layer-separating particles composed of a layered compound. Further, by separating the layers, the surface area can be increased, a functional group having substantially high reactivity can be effectively used, and more organic compound (A) can be adsorbed. Especially, since hydrotalcite has many hydroxyl groups on the surface, the amount of the organic compound (A) adsorbed to it can be increased by using hydrotalcite as inorganic particles. Furthermore, since hydrotalcite is a neutral compound having both acid-base sites, even when dispersed in various resins, the composition can be stably formed without attacking the resin itself. Therefore, hydrotalcite can exhibit stable oxygen absorption even when used in an oxygen-absorbing composition.

  The organic compound (A) includes a functional group that reacts with the surface of the inorganic particle, and when the inorganic particle includes a hydroxyl group on the surface, the organic compound (A) includes a functional group that reacts with the hydroxyl group. Examples of the functional group having high reactivity with a hydroxyl group include a carboxyl group, an ester group, an aldehyde group, an alkoxysilyl group, and an amino group. That is, examples of the organic compound (A) include at least one compound selected from the group consisting of carboxylic acids, esters, aldehydes, alkoxysilane derivatives, and amines. When these compounds react with the hydroxyl groups on the surface of the inorganic particles, an organic compound chemically adsorbed on the surface of the inorganic particles is formed.

  Usually, a part of the organic compound (A) (for example, a hydrogen atom or a hydroxyl group) is eliminated by forming water or the like when reacting with the hydroxyl group on the surface of the inorganic particles. For example, when the reactive functional group is a carboxyl group, an ester group, or an aldehyde group, the functional group is bonded to the inorganic particles at the —C—O— moiety. In the case where the reactive functional group is an alkoxysilyl group, the functional group is bonded to the inorganic particles at the -Si-O- moiety. Moreover, when the functional group to react is an amino group, it will couple | bond with an inorganic particle by the nitrogen part.

  The organic compound (A) and the organic compound chemically adsorbed on the inorganic particles are selected from the group consisting of carboxylic acid, ester, aldehyde, alkoxysilane derivative, and amine including the structure represented by the above formula (1). May be at least one compound.

  In addition, the organic compound (A) and the organic compound chemically adsorbed on the inorganic particles include a group consisting of carboxylic acid, ester, aldehyde, alkoxysilane derivative, and amine, including the structure represented by the above formula (2). It may be at least one compound selected from the above.

  The organic compound (A) and the organic compound chemically adsorbed on the inorganic particles are carboxylic acid, ester, aldehyde, derivative and amine having an unsaturated alicyclic structure of 5 to 10 members. It may be at least one compound selected from the group consisting of By using a compound having an unsaturated alicyclic structure, it is possible to suppress the decomposition of the organic compound (A) during oxygen absorption and the generation of low molecular weight substances, thereby preventing the generation of odor accompanying oxygen absorption. Can be suppressed. Note that hydrogen bonded to carbon constituting the cyclic structure may be substituted with another substituent. When a plurality of substituents are present, they may be the same or different. Examples of the substituent include a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, a halogen atom, a cyclic substituent including a methylene group, and an oxymethylene group. Including cyclic substituents.

  Representative carboxylic acids applicable as the organic compound (A) include, for example, palmitoleic acid, oleic acid, linoleic acid, linolenic acid, arachidonic acid, docosahexaenoic acid, eicosapentaenoic acid, parinaric acid, dimer acid, linseed oil fatty acid, Examples include unsaturated carboxylic acids such as soybean oil fatty acid, tung oil fatty acid, sugar oil fatty acid, sesame oil fatty acid, cottonseed oil fatty acid, rapeseed oil fatty acid, fish oil fatty acid and tall oil fatty acid. Among these, since linolenic acid has three double bonds in the molecule, an oxygen absorber having a high oxygen absorption capacity per molecule and a high oxygen absorption capacity can be obtained. When a photocatalyst is used as the oxygen absorption accelerator, in addition to the unsaturated carboxylic acid, for example, saturated aliphatic monocarboxylic acid such as formic acid, acetic acid, propionic acid, butyric acid, stearic acid; oxalic acid, malonic acid, succinic acid Saturated aliphatic dicarboxylic acids such as glutaric acid, adipic acid, and sebacic acid; aromatic carboxylic acids such as benzoic acid, phthalic acid, and terephthalic acid are also applicable.

  Moreover, as typical ester applicable as an organic compound (A), ester of the said carboxylic acid is mentioned.

  Further, as typical aldehydes applicable as the organic compound (A), for example, crotonaldehyde, sensionaldehyde, pentenal, hexenal, 7-octenal, nonenal, decenal, 2,4-hexadienal, 3-cyclohexenecarbox Examples include aldehyde, 5-norbornene-2-carboxaldehyde, acrolein, methacrolein and the like. When using a photocatalyst as an oxygen absorption accelerator, in addition to the unsaturated aldehyde, for example, acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, valeraldehyde, isovaleraldehyde, hexanal, octanal, nonanal, decanal, nonane dial, etc. Saturated aliphatic aldehydes can also be applied.

  Moreover, as a typical alkoxysilane derivative applicable as the organic compound (A), that is, a compound having an alkoxysilyl group, for example, a compound containing a trimethoxysilyl group, a triethoxysilyl group, or the like can be given. The portion other than the alkoxysilyl group is not particularly limited. For example, it may have a halogen, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, or a substituent. An atomic group such as an alkynyl group, an aryl group that may have a substituent, an alkylaryl group that may have a substituent, an alkoxy group, a carboxyl group, an acyl group, or a cyano group may be included.

  Representative amines applicable as the organic compound (A) include, for example, allylamine, oleylamine, N-methylallylamine, diallylamine, N, N′-diethyl-2-butene-1,4-diamine, and N-allylcyclopentyl. Examples include amine, allylcyclohexylamine, and 2- (1-cyclohexenyl) ethylamine. When a photocatalyst is used as the oxygen absorption accelerator, in addition to the unsaturated amine, for example, methylamine, ethylamine, propylamine, isopropylamine, butylamine, isobutylamine, secondary butylamine, tertiary butylamine, amylamine, isoamylamine, tertiary Liamylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, diisobutylamine, dipentylamine, dihexylamine, dioctylamine, ethylenediamine, 1,3-diaminopropane, 1,2-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, Saturated aliphatic amines such as 1,8-diaminooctane, 1,9-diaminononane and 1,10-diaminodecane are also applicable.

  Among these compounds, carboxylic acid is preferable because it can be strongly adsorbed on the surface of the inorganic particles.

  The molecular weight of the organic compound (A) is not particularly limited. However, when the formula weight of the organic compound chemically adsorbed on the inorganic particles is 3000 or less (for example, 500 or less), dispersion into the resin is facilitated. Therefore, the molecular weight of the organic compound (A) is preferably 3000 or less (for example, 500 or less).

  The oxygen absorption promoter is an additive for promoting oxygen absorption. Oxidation of the organic compound (A) chemisorbed on the inorganic particles is promoted by the oxygen absorption promoter, and as a result, oxygen in the atmosphere is consumed. Since the oxygen absorbent of the present invention contains an oxygen absorption accelerator, the inorganic particles need not have a photocatalytic function. 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 thereof include acid imides and N, N-dihydroxypyromellitic acid diimide. Among these, N-hydroxysuccinimide, N-hydroxymaleimide, N-hydroxyhexahydrophthalimide, N, N'-dihydroxycyclohexanetetracarboxylic diimide, N-hydroxyphthalimide, N-hydroxytetra Bromophthalimide and N-hydroxytetrachlorophthalimide are particularly preferred.

  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 oxygen absorption accelerator may be simply mixed with the inorganic particles or may be adsorbed on the inorganic particles. In addition, the inorganic particles and the oxygen absorption accelerator may be dispersed in a dispersion medium such as a resin.

  In the oxygen absorbent according to Embodiment 1, it is important that the organic compound (A) is chemisorbed (chemically bonded) to the surface of the inorganic particles. Such chemisorption can be realized by the method of the second embodiment, for example.

  Since the oxygen absorbent of the present invention can be used in the form of powder, it can be easily dispersed uniformly in the resin. For this reason, a uniform oxygen-absorbing composition can be easily obtained. In addition, in the oxygen absorbent of the present invention, the organic compound (A) is chemically adsorbed on the surface of the inorganic particles. Therefore, compared to a conventional oxygen absorbent in which the organic compound is not chemically adsorbed on the inorganic particles, the following An effect is obtained. (1) Oxygen absorption ability higher than that of physical adsorption can be obtained by chemical adsorption. (2) Unlike the case of physical adsorption, bleed-out hardly occurs. (3) The organic compound (A) can be prevented from volatilizing from the vent when blended with the resin. (4) Although it is preferable to wash the oxygen absorbent before blending in order to prevent the liberated organic compound from being decomposed when blended with the resin, unlike the case of physical adsorption, the organic compound is used during washing. It can suppress that (A) falls off from the surface of an inorganic particle. (5) Unlike the case of physical adsorption, the obtained resin composition can suppress elution into a solvent.

(Embodiment 2)
In Embodiment 2, the method of the present invention for producing an oxygen absorbent will be described. In addition, the oxygen absorbent manufactured by the method of Embodiment 2 is one of the oxygen absorbents of this invention.

The production method of the present invention includes a step of chemically adsorbing an unsaturated organic compound to inorganic particles. The organic compound (A) and inorganic particles described in Embodiment 1 can be applied to the unsaturated organic compound and inorganic particles.
The inorganic particles are usually used in the form of a powder that is an aggregate of inorganic particles.

  Below, two examples are given and demonstrated about the process in case an inorganic particle has a hydroxyl group on the surface and an organic compound (A) has a functional group which reacts with a hydroxyl group.

  In the first method, first, a mixture of an organic compound (A), inorganic particles, and an organic solvent is prepared (step 1a). Any organic solvent may be used as long as it can uniformly disperse or dissolve the organic compound and the inorganic particles. Examples of such an organic solvent include toluene, xylene, diisopropyl ether, tetrahydrofuran (THF), methylene chloride, chloroform, methyl acetate, ethyl acetate and the like. Among these, hexane and toluene are preferable because water generated when the organic compound (A) reacts with the hydroxyl group on the surface of the inorganic particles can be removed by azeotropic dehydration.

  Next, the organic solvent is removed from the mixture (step 2a). The method for removing the organic solvent is not particularly limited, and for example, at least one of filtration, drying under reduced pressure, and heating can be applied. By selecting the types of the organic compound (A), inorganic particles, and organic solvent, there are cases where a part of the organic compound (A) can be chemically adsorbed onto the inorganic particles by the step 2a.

  In the second method, first, a mixture containing the organic compound (A) and inorganic particles is prepared (step 1b). Next, the organic compound (A) is chemically adsorbed onto the inorganic particles by heating the mixture (step 2b).

  In the method of the present invention, it is particularly preferable to remove water generated by the reaction between the functional group and the hydroxyl group in Step 2a and Step 2b. By removing water, the reaction between the functional group of the organic compound (A) and the hydroxyl group on the surface of the inorganic particles can be promoted, and the proportion of the organic compound (A) that is chemisorbed can be increased. Therefore, when heating is performed in Step 2a and Step 2b, it is preferably performed in an atmosphere in which water is easily removed, such as under a nitrogen atmosphere such as a nitrogen stream or under reduced pressure. Similarly, step 2a and step 2b preferably include a step of heating the mixture at a temperature equal to or higher than the boiling point of water. The heating is preferably performed at a temperature lower than the decomposition temperature of the organic compound (A). When removing water in step 2a, the organic solvent and water may be removed separately or simultaneously. For example, after removing the organic solvent, the mixture from which the organic solvent has been removed may be heated at a temperature equal to or higher than the boiling point of water.

  According to the said process, the inorganic substance particle which the organic compound (A) chemisorbed (chemical bond) is obtained. The oxygen absorption accelerator described in Embodiment 1 may be adsorbed on the inorganic particles together with the organic compound (A) during the above process, or may be adsorbed on the inorganic particles after the above process. Moreover, you may dry blend the inorganic particle and oxygen absorber which are obtained at the said process. Moreover, you may disperse | distribute the inorganic particle and oxygen absorber which are obtained at the said process to dispersion media, such as resin.

  In this way, the oxygen absorbent described in Embodiment 1 is obtained. In addition, the oxygen absorbents of Embodiments 1 and 2 may be used alone or may be used by being dispersed in a resin or the like.

(Embodiment 3)
In Embodiment 3, the oxygen-absorbing composition of the present invention will be described. The oxygen-absorbing composition of Embodiment 3 includes a resin (polymer compound) and an oxygen absorbent dispersed in the resin. The oxygen absorbent is the oxygen absorbent described in the first or second embodiment.

  There is no limitation in particular in the quantity of the oxygen absorber contained in the composition of Embodiment 3, It adjusts according to the objective. In an example composition, the amount of the oxygen absorbent with respect to 100 parts by weight of the resin is, for example, in the range of 1 to 30 parts by weight, and preferably in the range of 1 to 10 parts by weight.

  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 3 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 generation of gels and fish eyes during the production of the composition.

  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, inorganic particles adsorbed with an organic compound 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. Further, the oxygen absorbent and the additive may be mixed and then mixed with the resin, or the oxygen absorbent and the resin may be mixed and then mixed with the additive. Moreover, you may mix with an oxygen absorber, after mixing an additive and resin. In these cases, the inorganic particles adsorbed with the organic compound and the oxygen absorption accelerator may be mixed in advance, or may be separately mixed with other components at different stages.

  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 4)
In Embodiment 4, the packaging material of the present invention will be described. The packaging material of the present invention includes a portion made of the oxygen-absorbing composition described in the third embodiment. This portion may have any shape, for example, a layer shape, a bottle shape, or a cap shape. This packaging material can be formed by processing the composition of Embodiment 3 into various shapes.

  The composition of Embodiment 3 may be formed into a shape such as a film, a sheet, and a pipe, for example, by 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.

  Although the packaging material of Embodiment 4 may be comprised only by the layer (henceforth a layer (A)) which consists of a composition of Embodiment 3, the layer (henceforth a layer (B) which consists of another material). ) 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 3 can be used.

  The manufacturing method of the laminated body of Embodiment 4 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 comprising the composition of Embodiment 3 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 3.

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

[Example 1]
In Example 1, the result of evaluating the oxygen absorbing ability of the oxygen absorbent of the present invention is shown. In the preparation of the following samples, Kyowado-500 manufactured by Kyowa Chemical Industry Co., Ltd. was used as the hydrotalcite powder.

(Sample 1)
4.00 g of linolenic acid was dissolved in 150 mL of degassed hexane, 16.0 g of hydrotalcite powder was added, and hexane was distilled off at a bath temperature of 80 ° C. in a nitrogen atmosphere. Next, the powder was heated for 3 hours with stirring at a bath temperature of 110 ° C. in a nitrogen atmosphere. Next, the powder was dried under reduced pressure to obtain hydrotalcite powder (sample 1) to which linolenic acid was chemically adsorbed.

(Sample 2)
100 mL of degassed hexane was added to 9.78 g of the oxygen absorbent in Sample 1, and the mixture was stirred at room temperature for 2 hours, and then suction filtered. Thus, the powder (sample 2) which wash | cleaned sample 1 with hexane was obtained.

(Sample 3)
2.00 g of linolenic acid was dissolved in 100 mL of hexane, 8.00 g of hydrotalcite powder was added, and the mixture was stirred at room temperature for 2 hours. The mixed liquid was subjected to suction filtration, and the obtained powder was dried under reduced pressure. In this way, a hydrotalcite powder (sample 3) adsorbed with linolenic acid was obtained.

(Comparative sample 1)
2.00 g of linolenic acid was dissolved in 100 mL of hexane, 8.00 g of activated carbon (manufactured by Kuraray Chemical Co., Ltd., BP-20) was added, and the mixture was stirred at room temperature for 2 hours. The mixed liquid was subjected to suction filtration, and the obtained powder was dried under reduced pressure. Thus, activated carbon powder (Comparative Sample 1) on which linolenic acid was physically adsorbed was obtained.

(Production and evaluation of oxygen absorber)
About 10 times the weight of degassed hexane was added to each of the above four types of powders and hydrotalcite powder as comparative sample 2, and cobalt naphthenate was added and mixed to 800 ppm in terms of cobalt. . From the mixed liquid, the solvent was distilled off under reduced pressure, and the obtained powder was dried. About 4 types of oxygen absorbers obtained in this way, 0.5 g of each was put into a bottle with a capacity of 260 cc in a room of 50% RH at 23 ° C., and the bottle was sealed. And this bottle was stored at 23 degreeC, the oxygen concentration in the bottle after a fixed period passed was measured, and the oxygen absorption rate of the oxygen absorbent was computed. The evaluation results are shown in FIG.

  The vertical axis in FIG. 1 indicates the amount of oxygen absorbed per gram of oxygen absorbent. As shown in FIG. 1, Samples 1 to 3 showed higher oxygen absorption capacity than Comparative Sample 1 in which linolenic acid was physically adsorbed on activated carbon. However, Sample 3 was inferior in oxygen absorption capacity to Samples 1 and 2. Further, Sample 2 obtained by washing Sample 1 produced by heat treatment did not show a significant characteristic deterioration as compared with Sample 1. The reason why the decrease in oxygen absorption capacity due to washing in sample 2 is small is considered to be because a large amount of linolenic acid is chemisorbed on the hydrotalcite of sample 1. On the other hand, Comparative Sample 2 showed almost no oxygen absorption.

When the infrared absorption spectrum of Samples 1 to 3 was measured by the KBr tablet method, a difference was found in peaks (1500 cm ^{−1 to} 1700 cm ⁻¹ ) derived from C═O stretching vibration. FIG. 2 shows an infrared absorption spectrum.

  The reason why the oxygen absorption capacity and the infrared absorption spectrum of Samples 1 to 3 are different is not clear, but it is considered that the amount of linolenic acid adsorbed and the state of adsorption differ depending on the treatment method.

[Example 2]
In Example 2, another example in which the oxygen absorbent of the present invention was produced and evaluated will be described.

(Sample 4)
First, in a nitrogen atmosphere, 2.00 g of linolenic acid was added with 2.0 mL of a hexane solution of cobalt naphthenate (the concentration of cobalt naphthenate was 0.8 mg / mL in terms of Co) and stirred to obtain a first solution. It was. On the other hand, 8.00 g of hydrotalcite powder was added to 100 mL of hexane and stirred to obtain a second solution. Next, the first solution was added dropwise to the second solution and mixed in a nitrogen atmosphere. The resulting liquid was heated at a bath temperature of 80 ° C., hexane was distilled off, and further heated at 120 ° C. for 2 hours in an oil bath, and then allowed to cool. The obtained powder was dried under reduced pressure to obtain a powder (sample 4) in which linolenic acid was mainly chemically adsorbed on hydrotalcite.

  0.5 g of the oxygen absorbent thus obtained was put into a bottle with a capacity of 260 cc in a 50% RH room at 23 ° C., and the bottle was sealed. And this bottle was stored at 23 degreeC, the oxygen concentration in the bottle after a fixed period passed was measured, and the oxygen absorption rate of the oxygen absorbent was computed. The evaluation results are shown in FIG. As shown in FIG. 3, Sample 4 showed an oxygen absorption capacity equal to or higher than that of Sample 3.

[Example 3]
In Example 3, another example in which the oxygen absorbent of the present invention was produced and evaluated will be described.

(Sample 5)
Dissolve 4.00 g of linolenic acid in 150 mL of degassed hexane, add 16.0 g of Somasif ME (Coop Chemical Co., Ltd.), a synthetic mica, and distill off hexane at a bath temperature of 80 ° C. in a nitrogen atmosphere. did. Next, the powder obtained by distilling off hexane was heated for 3 hours with stirring at a bath temperature of 110 ° C. in a nitrogen atmosphere. Next, the powder was dried under reduced pressure to obtain Somasif ME powder (sample 5) in which linolenic acid was chemisorbed.

(Production and evaluation of oxygen absorber)
About 10 times the weight of degassed hexane was added to Sample 5, and cobalt naphthenate was further added and mixed so as to be 800 ppm in terms of cobalt. From the mixed liquid, the solvent was distilled off under reduced pressure, and the obtained powder was dried. 0.5 g of the oxygen absorbent thus obtained was put into a bottle with a capacity of 260 cc in a 50% RH room at 23 ° C., and the bottle was sealed. And this bottle was stored at 23 degreeC, the oxygen concentration in the bottle after a fixed period passed was measured, and the oxygen absorption rate of the oxygen absorbent was computed. The evaluation results are shown in FIG.

[Example 4]
In Example 4, another example in which the oxygen absorbent of the present invention was produced and evaluated will be described.

(Sample 6)
4.00 g of eicosapentaenoic acid ethyl ester was dissolved in 150 mL of degassed hexane, 16.0 g of hydrotalcite powder was added, and hexane was distilled off at a bath temperature of 80 ° C. in a nitrogen atmosphere. Next, the powder obtained by distilling off hexane was heated for 3 hours with stirring at a bath temperature of 110 ° C. in a nitrogen atmosphere. Next, the powder was dried under reduced pressure to obtain a hydrotalcite powder (sample 6) onto which eicosapentaenoic acid had been chemically adsorbed.

(Production and evaluation of oxygen absorber)
About 10 times the weight of degassed hexane was added to Sample 6, and cobalt naphthenate was further added to 800 ppm in terms of cobalt and mixed. From the mixed liquid, the solvent was distilled off under reduced pressure, and the obtained powder was dried. 0.5 g of the oxygen absorbent thus obtained was put into a bottle with a capacity of 260 cc in a 50% RH room at 23 ° C., and the bottle was sealed. And this bottle was stored at 23 degreeC, the oxygen concentration in the bottle after a fixed period passed was measured, and the oxygen absorption rate of the oxygen absorbent was computed. The evaluation results are shown in FIG.

[Example 5]
In Example 5, an example of producing a press film made of an oxygen-absorbing composition will be described.

(Sample 7)
First, the hydrotalcite powder (sample 1) chemically adsorbed with linolenic acid described in Example 1 was prepared. About 10 times the weight of degassed hexane was added to Sample 1, and cobalt naphthenate was further added to 800 ppm in terms of cobalt and mixed. From the liquid after mixing, the solvent was distilled off under reduced pressure, and the resulting powder was dried to obtain an oxygen absorbent. Next, 10 parts by weight of the oxygen absorbent thus obtained and 90 parts by weight of EVOH were mixed and melt blended for 5 minutes. Blending was performed under a nitrogen atmosphere. And the obtained mixture was pressed to about 100 micrometers in thickness with the compression molding machine, and the press film (sample 7) was produced.

  0.5 g of Sample 7 was put into a 85 cc bottle at 23 ° C. in a 50% RH room, and the bottle was sealed. And this bottle was stored at 23 degreeC, the oxygen concentration in the bottle after a fixed period passed was measured, and the oxygen absorption rate of the oxygen absorbent was computed. The evaluation results are shown in FIG.

  The embodiments of the present invention have been described above by way of examples, but the present invention is not limited to the above-described embodiments, and can be applied to other embodiments based on the technical idea of the present invention.

  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.

Claims (25)

An oxygen absorbent comprising inorganic particles, an organic compound chemisorbed on the inorganic particles, and an oxygen absorption accelerator,
The organic compound is an organic compound formed by the reaction of the organic compound (A) with the inorganic particles,
The organic compound (A) is an oxygen absorbent that is a carboxylic acid (excluding oleic acid and ricinoleic acid) or an ester of carboxylic acid, and has a molecular weight of 500 or less.   The oxygen absorbent according to claim 1, wherein the organic compound is an unsaturated organic compound. The oxygen absorbent according to claim 2, wherein the organic compound includes a structure represented by the following formula (1).
[Wherein, R ¹ and R ² are each independently a hydrogen atom, an alkyl group, an alkyl group having a substituent, an aryl group, an aryl group having a substituent, an alkylaryl group, an alkylaryl group having a substituent, It is one selected from —COOR ³ , —OCOR ³ , a cyano group and a halogen atom. R ³ is one selected from an alkyl group, an alkyl group having a substituent, an aryl group, an aryl group having a substituent, an alkylaryl group, and an alkylaryl group having a substituent. ] The oxygen absorbent according to claim 2, wherein the organic compound includes a structure represented by the following formula (2).
[Wherein, R ⁴ and R ⁵ each independently represents a hydrogen atom, an alkyl group, an alkyl group having a substituent, an aryl group, an aryl group having a substituent, an alkylaryl group, an alkylaryl group having a substituent, It is one selected from —COOR ³ , —OCOR ³ , a cyano group and a halogen atom. R ³ is one selected from an alkyl group, an alkyl group having a substituent, an aryl group, an aryl group having a substituent, an alkylaryl group, and an alkylaryl group having a substituent. ]   The oxygen absorbent according to claim 2, wherein the organic compound has an unsaturated alicyclic structure.   The oxygen absorbent according to claim 1, wherein the organic compound (A) is at least one selected from the group consisting of linolenic acid, eicosapentaenoic acid, and esters thereof.   The oxygen absorbent according to any one of claims 1 to 6, wherein the inorganic particles are made of a layered inorganic compound.   The oxygen absorbent according to any one of claims 1 to 7, wherein the inorganic particles have a hydroxyl group on a surface thereof.   The oxygen absorbent according to claim 8, wherein the inorganic particles are hydrotalcite particles.   The oxygen absorber according to any one of claims 1 to 9, wherein the oxygen absorption accelerator is at least one selected from a transition metal salt, a radical generator, and a photocatalyst. The organic compound (A), Ru carboxylic acid der unsaturated, oxygen-absorbing agent according to any one of claims 1 to 5. A method for producing an oxygen absorbent comprising inorganic particles and an oxygen absorption accelerator, comprising a step of chemically adsorbing an organic compound to the inorganic particles,
The method for producing an oxygen absorbent, wherein the organic compound is a carboxylic acid (excluding oleic acid and ricinoleic acid) or an ester of a carboxylic acid and has a molecular weight of 500 or less.   The method for producing an oxygen absorbent according to claim 12, wherein the organic compound is an unsaturated organic compound.   The method for producing an oxygen absorbent according to claim 12 or 13, wherein the inorganic particles have a hydroxyl group on the surface. (I) preparing a mixture containing the organic compound, the inorganic particles, and an organic solvent;
(Ii) The method for producing an oxygen absorbent according to any one of claims 12 to 14, comprising a step of removing the organic solvent from the mixture.   The method for producing an oxygen absorbent according to claim 15, further comprising a step of heating the mixture at a temperature equal to or higher than a boiling point of water after the step (ii). (I) preparing a mixture containing the organic compound and the inorganic particles;
(II) The method for producing an oxygen absorbent according to any one of claims 12 to 14, further comprising a step of chemically adsorbing the organic compound onto the inorganic particles by heating the mixture.   The method for producing an oxygen absorbent according to claim 17, wherein the step (II) includes a step of heating the mixture at a temperature equal to or higher than a boiling point of water.   The method for producing an oxygen absorbent according to any one of claims 16 to 18, wherein the mixture is heated under a nitrogen atmosphere or under reduced pressure.   The method for producing an oxygen absorbent according to any one of claims 12 to 19, wherein the inorganic particles are made of a layered inorganic compound. The organic compound is Ru carboxylic acid der unsaturated, method for producing the oxygen-absorbing agent according to any one of claims 12 to 20.   The oxygen absorbent manufactured by the manufacturing method of any one of Claims 12-21. An oxygen-absorbing composition comprising a resin and an oxygen absorbent dispersed in the resin,
An oxygen-absorbing composition, wherein the oxygen absorbent is the oxygen absorbent according to any one of claims 1 to 11 and 22.   The oxygen-absorbing composition according to claim 23, wherein the resin contains an ethylene-vinyl alcohol copolymer.   A packaging material comprising a portion made of the oxygen-absorbing composition according to claim 23 or 24.