WO2005079974A1

WO2005079974A1 - Oxygen absorbent, method for producing same, and oxygen absorbing composition and packaging material using same

Info

Publication number: WO2005079974A1
Application number: PCT/JP2005/002332
Authority: WO
Inventors: Yoshihisa Tsuji; Mie Kodani; Tomoyuki Watanabe; Hideharu Iwasaki
Original assignee: Kuraray Co., Ltd.
Priority date: 2004-02-23
Filing date: 2005-02-16
Publication date: 2005-09-01
Also published as: JP4865542B2; JPWO2005079974A1; TW200533301A

Abstract

Disclosed is an oxygen absorbent which contains a particle functioning as a photocatalyst and an organic compound chemically adsorbed on the surface of the particle. Such an oxygen absorbent can be produced by a manufacturing process including a step for having an organic compound chemically adsorbed on the surface of a particle which functions as a photocatalyst. This oxygen absorbent enables to obtain a resin composition having a high oxygen-absorbing power. Also disclosed are an oxygen-absorbing resin composition and packaging material using this oxygen absorbent.

Description

Specification

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

Technical field

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

Background art

[0002] In order to stably store articles, such as foods, which are largely degraded by oxygen, it is important to store them in an environment with low oxygen content. Various oxygen absorbers have been proposed to enable such storage. As such an oxygen absorbent, an oxygen absorbent using titanium dioxide has been disclosed (for example, JP-A-7-316342, JP-A-11-12115, and JP-A-11-278845). JP-A-2000-86415, JP-A-2000-316547, JP-A-2000-344958, JP-A-2001-226207, and JP-A-2002-320917).

[0003] However, the oxygen absorbers conventionally proposed have a problem in that the dispersibility when dispersed in a polymer is poor. In addition, there is a problem that the performance is greatly reduced when dispersed in a polymer.

Disclosure of the invention

[0004] In view of such circumstances, the present invention provides an oxygen absorbent capable of constituting a resin composition having a high oxygen absorbing ability, a method for producing the same, and an oxygen-absorbing resin composition using the same. One of the purposes is to provide packaging materials.

[0005] In order to achieve the above object, the oxygen absorbent of the present invention includes particles that function as a photocatalyst, and an organic compound (organic group) chemically adsorbed on the surface of the particles.

In the oxygen absorber of the present invention, the organic compound is an organic compound formed by reacting an organic compound (A) containing a functional group that reacts with a hydroxyl group with a hydroxyl group on the surface of the particle.ても

[0007] In the oxygen absorbent of the present invention, the particles may contain titanium dioxide. The book above In the oxygen absorbent of the present invention, the titanium diacid may be an anatase-type titanium nitrate.

[0008] In the oxygen absorber of the present invention, the organic compound (A) may be at least one compound selected from the group consisting of a carboxylic acid, an ester, an aldehyde, an alkoxysilane derivative and an amine. The organic compound and the organic compound (A) are preferably organic compounds having a structure that is easily oxidized, for example, an organic compound having a methylene group at the _a- position of _a carbonyl group, or an α-form of an ethylenic double bond. Organic compounds having a methylene group at the (aryl) position are preferred. In the oxygen absorbent of the present invention, the formula weight of the organic compound may be 3000 or less. In the above oxygen absorber of the present invention, the organic compound (Α) may be succinic acid.

[0009] Further, the method of the present invention for producing an oxygen absorbent includes a step of adsorbing an organic compound on the surface of particles functioning as a photocatalyst.

[0010] In the above production method, the particles may have a hydroxyl group on the surface, and the organic compound may include a functional group that reacts with the hydroxyl group.

[0011] In the above production method, the organic compound may be at least one compound selected from the group consisting of a carboxylic acid, an ester, an aldehyde, an alkoxysilane derivative and an amine.

[0012] In the above production method, the particles may contain titanium dioxide.

[0013] The above-mentioned production method may include: (i) a step of preparing a mixture containing the organic compound, the particles, and an organic solvent; and (ii) a step of removing the organic solvent from the mixture. Yo!ヽ. In this case, a step of heating the mixture from which the organic solvent has been removed at a temperature equal to or higher than the boiling point of water may be included.

[0014] The production method includes: (I) a step of preparing a mixture containing the organic compound and the particles; and (II) a step of chemically adsorbing the organic compound to the particles by heating the mixture. 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.

[0015] In the above production method, the mixture may be heated under a nitrogen atmosphere or under reduced pressure.

[0016] Another oxygen absorbent of the present invention is the oxygen absorbent produced by the production method of the present invention. It is an absorbent.

[0017] The oxygen-absorbing composition of the present invention is an oxygen-absorbing composition comprising a resin and an oxygen-absorbing agent dispersed in the resin, wherein the oxygen-absorbing agent is the oxygen-absorbing composition of the present invention. It is an absorbent. In this oxygen-absorbing composition, the resin may include an ethylene-vinyl alcohol copolymer.

[0018] The packaging material of the present invention includes a portion composed of the oxygen-absorbing composition.

Since the oxygen absorbent of the present invention is in the form of particles, it is easy to uniformly disperse it in resin. In addition, the oxygen absorbent of the present invention exhibits high oxygen absorbing ability because the organic compound to be oxidized is chemically adsorbed on the photocatalyst particles. Since the oxygen absorbent of the present invention is activated by light irradiation, by controlling the timing and amount of light irradiation, it is possible to control the timing and intensity of the development of the oxygen absorbing ability. Further, by preventing the irradiation of light, the expression of oxygen absorption ability can be suppressed, so that storage and the like are easy.

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

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

Brief Description of Drawings

FIG. 1 is a graph showing an example of the oxygen absorbing ability of the oxygen absorbent of the present invention and the oxygen absorbent of the comparative example.

FIG. 2 is a view showing one example of an infrared absorption spectrum of the oxygen absorbent of the present invention.

FIG. 3 is a graph showing another example of the oxygen absorbing ability of the oxygen absorbent of the present invention.

[FIG. 4] FIG. 4 shows the oxygen absorbing ability of the press film which also provides the oxygen absorbing composition of the present invention. 6 is a graph showing an example of the above.

FIG. 5 is a graph showing another example of the oxygen-absorbing ability of a press film which also provides the oxygen-absorbing composition of the present invention.

FIG. 6 is a graph showing another example of the oxygen-absorbing ability of a press film which also provides the oxygen-absorbing composition of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described. In the following description, specific compounds are described as compounds that exhibit a specific function, but the present invention is not limited thereto. Further, the exemplified materials may be used alone or in combination unless otherwise specified.

(Embodiment 1)

Embodiment 1 describes the oxygen absorbent of the present invention. The oxygen absorbent of the present invention includes particles that function as a photocatalyst (hereinafter, referred to as photocatalyst particles) and an organic compound (organic group) chemically adsorbed to the photocatalyst particles. The organic compound chemically adsorbed on the photocatalyst particles may be any organic compound that is oxidized by the catalytic action of the photocatalyst particles. The organic compound is formed when an organic compound containing a functional group that reacts with the surface of the photocatalyst particles (hereinafter, may be referred to as “organic compound (A)”) reacts with the surface of the photocatalyst particles. The ratio between the photocatalyst particles and the organic compound (A) adsorbed on the photocatalyst particles 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 on the photocatalyst particles may be in the range of 1 part by weight to 100 parts by weight, preferably 1 part by weight to 10 parts by weight, per 100 parts by weight of the photocatalyst particles.

[0025] The average particle size of the photocatalyst particles is not particularly limited, but is preferably 100 nm or less, more preferably 500 nm or less, and more preferably 500 nm or less. By setting the average diameter of the photocatalyst particles to 100 nm or less, the photocatalytic function can be improved by increasing the surface area. Further, by setting the average particle size to 100 nm or less, dispersibility in a polymer can be improved, and transparency can be imparted.

[0026] Examples of the material of the photocatalyst particles include titanium dioxide, tungsten oxide, zinc oxide, cerium oxide, strontium titanate, and potassium niobate. Among these However, since it is recognized as a food additive with a high photocatalytic function and is safe and inexpensive, the photocatalyst particles preferably contain titanium dioxide, typically only the titanium dioxide. Particles are used.

When the photocatalyst particles are titanium dioxide particles, the particles are preferably at least 30% by weight of the titanium dioxide powder (the whole particles), which is preferably an anatase-type titanium dioxide powder (all particles). (More preferably 50% by weight or more) is preferably anatase-type titanium dioxide. By using anatase-type titanium dioxide particles, a high photocatalytic action can be obtained.

[0028] The photocatalyst particles preferably have a functional group on the surface, and particularly preferably have a hydroxyl group. Representative examples of such photocatalyst particles include titanium dioxide particles.

[0029] When the surface of the photocatalyst particle contains a hydroxyl group, the organic compound (A) containing a functional group that reacts with the hydroxyl group reacts with the hydroxyl group, so that the organic compound chemically adsorbed on the photocatalyst particle is converted. It is formed. Examples of the functional group having high reactivity with a hydroxyl group include a carboxy group, an ester group, an aldehyde group, an alkoxysilyl group, and an amino group. That is, as the organic compound (A), for example, at least one compound selected from the group consisting of a carboxylic acid, an ester, an aldehyde, an alkoxysilane derivative and an amine can be used. Such an organic compound (A) has a functional group that reacts with the surface of the photocatalyst particles, and is more efficient than a hydrocarbon by an oxide ion (O ² ) ゃ hydroxyl radical (OH). It is acidified. The carboxylic acid may be in the form of a salt. Further, by using a compound containing a carbon-carbon double bond as the organic compound (), higher oxygen absorbing ability may be obtained in some cases.

Normally, a part of the organic compound (A) (for example, a hydrogen atom or a hydroxyl group) forms water and the like when it reacts with a hydroxyl group on the surface of the photocatalyst particles, and is eliminated. For example, when the functional group to be reacted is a carboxyl group, an ester group or an aldehyde group, it is bonded to the photocatalyst particles by a C O— moiety thereof. When the reactive functional group is an alkoxysilyl group, the functional group is bonded to the photocatalyst particles at the -Si-O- portion or the like. When the functional group to be reacted is an amino group, it binds to the photocatalyst particles at the nitrogen portion or the like.

[0031] The organic compound (A) is one that is oxidized by irradiating the photocatalyst particles with light. Just fine. The organic compound (A) may be a saturated compound or an unsaturated compound. When the organic compound (A) is an unsaturated compound, it is preferable that the methylene group adjacent to the unsaturated bond is not substituted. According to such a configuration, a high oxygen absorbing ability can be obtained, and generation of a low-molecular compound due to oxidation of an organic compound can be suppressed.

[0032] Representative carboxylic acids applicable as the organic compound (A) include, for example, saturated aliphatic monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, and stearic acid; oxalic acid, malonic acid, succinic acid, and the like. Saturated aliphatic dicarboxylic acids such as daltaric acid, adipic acid and sebacic acid; unsaturated aliphatic carboxylic acids such as acrylic acid, propiolic acid, methacrylic acid, crotonic acid, oleic acid, maleic acid and fumaric acid; benzoic acid, phthalic acid, And aromatic carboxylic acids such as terephthalic acid. Among them, when succinic acid is used, an effect that oxidation by a photocatalyst proceeds efficiently is obtained.

[0033] Representative esters applicable as the organic compound (A) include the above-mentioned esters of carboxylic acids.

[0034] Typical aldehydes applicable as the organic compound (A) include, for example, acetoaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, valeraldehyde, isovaleraldehyde, hexanal, otatanal, 7- otatenal, nona Examples include nal, decanal, crotonaldehyde, senesionaldehyde, acrolein, methacrolein, and nonangial.

Examples of a typical alkoxysilane derivative applicable as the organic compound (A), that is, a compound having an alkoxysilyl group include, for example, a compound containing a trimethoxysilyl group ゃ a triethoxysilyl group. Although there is no particular limitation on the portion other than the alkoxysilyl group, for example, halogen, an alkyl group optionally having a substituent, an alkyl group optionally having a substituent, and a substituent Groups such as an alkyl group which may be substituted, an aryl group which may have a substituent, an alkylaryl group which may have a substituent, an alkoxy group, a carboxyl group, an acyl group and a cyano group. May be included.

[0036] Typical amines applicable as the organic compound (A) include, for example, methylamine, ethynoleamine, propylamine, isopropylamine, butynoleamine, isobutynoleamine, secondary butyramine, tertiary butyramine, Amylamine, isoamylamine Tertiary amylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, dimethylamine, getylamine, dipropylamine, dibutylamine, diisobutylamine, dipentylamine, dihexylamine, dioctylamine, ethyldiamine, 1,3-diamine. , 1,2-diaminopropane, 1,4-diaminobutane

, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane and the like.

[0037] Among these compounds, carboxylic acids can be strongly chemically adsorbed on the surface of the photocatalyst particles. Among carboxylic acids, dicarboxylic acids are preferred because they can be more strongly chemically adsorbed on the surface of the photocatalyst particles.

[0038] The molecular weight of the organic compound (A) is not particularly limited. However, by setting the formula weight of the organic compound chemically adsorbed to the photocatalyst particles to 3000 or less (for example, 500 or less), dispersion into the resin can be prevented. It will be easier. Therefore, the molecular weight of the organic compound (A) is preferably 3000 or less (for example, 500 or less).

[0039] In the oxygen absorbent of the first embodiment, it is important that the organic compound chemically adsorbs to the surface of the photocatalyst particles. Such chemisorption can be realized, for example, by the method of the second embodiment.

[0040] Since the oxygen absorbent of the present invention can be used in the form of a powder, it is easy to uniformly disperse it in resin. Therefore, a uniform oxygen-absorbing composition can be easily obtained. Further, in the oxygen absorbent of the present invention, since the organic compound is chemically adsorbed on the surface of the photocatalyst particles, the following effects are obtained as compared with the conventional oxygen absorbent in which the organic compound is not chemically adsorbed on the photocatalyst particles. can get. (1) Unlike physical adsorption, bleed-out hardly occurs even when dispersed in resin. (2) The organic compound (A) can be prevented from volatilizing from the vacuum vent when blended with the resin. (3) It is preferable to wash the oxygen absorbent before blending because the organic compound released when blended with the fat is decomposed. However, unlike the case of physical adsorption, the organic compound (A ) Can be prevented from falling off the surface of the photocatalytic particles. (4) When compared after washing, higher oxygen absorption capacity can be obtained by chemical adsorption than in the case of physical adsorption. (5) Unlike the case of physical adsorption, the obtained resin composition has reduced elution to a solvent. (Embodiment 2)

Embodiment 2 describes a method of the present invention for producing an oxygen absorbent. The oxygen absorbent produced by this method is one of the oxygen absorbents of the present invention.

[0042] The production method of the present invention includes a step of adsorbing an organic compound on the surface of particles functioning as a photocatalyst (photocatalyst particles). As the photocatalyst particles and the organic compound, the photocatalyst particles and the organic compound (A) described in Embodiment 1 can be used.

Hereinafter, the production method of the present invention will be described with reference to two examples.

[0044] In the first method, first, a mixture of the organic compound (A), the photocatalyst particles, and the organic solvent is prepared (step la). The organic solvent may be any as long as it can uniformly disperse or dissolve the organic compound and the photocatalyst particles. Examples of such an organic solvent include hexane, heptane, toluene, xylene, diisopropyl ether, tetrahydrofuran (THF), methylene chloride, chloroform, methyl acetate, and ethyl acetate. Among them, by using hexane, toluene or the like, water generated when the organic compound (A) reacts with the hydroxyl group on the surface of the photocatalyst 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 type of the organic compound (A), the photocatalyst particles and the organic solvent, a part of the organic compound (A) can be chemically adsorbed to the photocatalyst particles in step 2a.

In the second method, first, a mixture containing the organic compound (A) and the photocatalyst particles is prepared (step lb). Next, the organic compound (A) is chemically adsorbed on the photocatalyst particles by heating the mixture (step 2b). In the second method, usually, the organic compound (and the photocatalyst particles are mixed without using a solvent.

When a hydroxyl group is present on the surface of the photocatalyst particle and the organic compound (A) has a functional group that reacts with the hydroxyl group, in step 2a and step 2b, water generated by the reaction between the functional group and the hydroxyl group is removed. Is particularly preferred. By removing water, the reaction between the functional group of the organic compound (A) and the hydroxyl group of the photocatalyst particles can be promoted, and the ratio of the chemically adsorbed organic compound (A) can be increased. Therefore, heating in step 2a and step 2b In the case of performing the treatment, it is preferable to perform the treatment in an atmosphere from which water can be 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 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 water is removed in step 2a, the organic solvent and water may be removed separately or simultaneously. For example, after removing the organic solvent, the mixture containing the organic compound (A) and the photocatalyst particles may be heated at a temperature equal to or higher than the boiling point of water.

[0048] The above step is preferably performed in a state where light (particularly, ultraviolet light) is blocked. Performing the above steps in a state in which light is blocked can prevent the performance of the oxygen absorbent from deteriorating.

According to the production method of Embodiment 2, an oxygen absorbent containing photocatalyst particles to which organic compound (A) is chemically adsorbed (chemically bonded) can be obtained. The oxygen absorbent of the present invention (the oxygen absorbent of Embodiments 1 and 2) may be used alone or may be used by dispersing it in a resin or the like.

[0050] The oxygen absorber of the present invention oxidizes an organic compound when irradiated with light to exhibit oxygen absorbing ability. Therefore, it is preferable to prevent the organic compound adsorbed on the photocatalyst particles from being oxidized by light irradiation before the start of use. Therefore, in the oxygen absorbent of the present invention, it is important to prevent light (particularly ultraviolet light) from being irradiated before use. When light is not irradiated before the start of use, the organic compound is not oxidized, and the photocatalyst particles do not significantly change. For example, when the photocatalyst particles are titanium dioxide particles, the amount of oxygen vacancies in the titanium dioxide particles before the start of use is preferably substantially the same as that before the adsorption of the organic compound. Specifically, before the start of use, the amount of oxygen atoms contained in the titanium dioxide particles after the organic compound is adsorbed is included in the titanium dioxide particles before the organic compound is adsorbed. It is preferably at least 95 atomic% (preferably at least 99 atomic%) of the amount of oxygen atoms used.

(Embodiment 3)

Embodiment 3 describes the oxygen-absorbing composition of the present invention. The oxygen-absorbing composition of Embodiment 3 includes a resin (polymer compound) and an oxygen absorbent dispersed in the resin. No. The oxygen absorbent is the oxygen absorbent described in the first or second embodiment.

[0052] The amount of the oxygen absorbent contained in the composition of Embodiment 3 is adjusted according to the purpose of the present invention, which is not particularly limited. In one example of the composition, the amount of the oxygen absorbent can be in the range of 1 part by weight to 30 parts by weight, more preferably 1 part by weight to 10 parts by weight, based on 100 parts by weight of the resin.

[0053] The resin is selected according to the use of the composition. Typical resins include, for example, synthetic resins such as polybutyl alcohol-based resins, polyamide-based resins, and polyacrylonitrile-based resins. Since these resins have high oxygen nobility, a composition suitable for a material of a packaging material of an article in which deterioration by oxygen is a problem can be obtained.

As a resin other than the above, for example, polyolefin such as polyethylene, polypropylene, poly 4-methyl-1 pentene, and poly 1-butene may be used. Further, an ethylene propylene copolymer, polyvinyl chloride, polyvinylidene, polyvinyl chloride, polystyrene, polycarbonate, or polyatalylate may be used. Further, polyesters such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate may be used. Further, a copolymer of ethylene or propylene with 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; itaconic acid, methacrylic acid, acrylic acid, and maleic anhydride. Unsaturated carboxylic acids, their salts, their partial or complete esters, their tolyls, their amides, their anhydrides; butyl formate, butyl acetate, butyl propionate, butyl butyrate, burotatanoate, burdedecanoate, Examples thereof include vinyl stearate, burarachidonic acid, and carboxylic acid butyl esters; butylsilane-based compounds such as butyltrimethoxysilane; unsaturated sulfonic acids or salts thereof; alkylthiols; and butylpyrrolidones.

[0055] Polyvinyl alcohol-based resins include a homopolymer of a bullet ester or a copolymer of a bullet ester and another monomer (particularly, a copolymer of a vinyl ester and ethylene), an alkali catalyst or the like. And obtained by performing ken-dani using Examples of the vinyl ester include, for example, butyl acetate. Other fatty acid butyl esters (vinyl propionate, burival vivalate, etc.) may be used.

[0056] The saponification degree of the butyl ester component of the polybutyl alcohol-based resin is preferably 90 moles. %, For example, 95 mol% or more. By setting the degree of Kendy to 90 mol% or more, it is possible to suppress a decrease in gas nori properties under high humidity. Note that two or more types of polyvinyl alcohol resins having different degrees of saponification may be used! The degree of Kendy of a polyvinyl alcohol-based resin can be determined by a nuclear magnetic resonance (NMR) method.

[0057] Suitable melt flow rate (MFR) of polyalcohol-based resin (210 ° C, under a load of 2160g, JIS K7210 [based on this method]) 0.1 0.1 lOOg / 10 minutes, more preferred 0.5 to 50 g / 10 min, more preferably 1 to 30 g ZlO. If the melt flow rate is out of the range of 0.1 lg-100g / 10 minutes, the workability during melt molding often deteriorates.

[0058] Among polybutyl alcohol resins, an ethylene butyl alcohol copolymer (hereinafter sometimes referred to as EVOH) can be melt-molded and has good gas barrier properties under high humidity. Has features. Ratio of ethylene units to total structural units of EVOH, for example 5 to 60 mole ^_0/0 (preferably 10 55 mole ^_0/0) is in the range of. By setting the proportion of the ethylene unit to 5 mol% or more, it is possible to suppress a decrease in gas nori- ness under high humidity. Further, by the ratio of ethylene units and 60 mole ^_0/0 or less, a high gas barrier barrier property is obtained. The proportion of ethylene units can be determined by nuclear magnetic resonance (NMR). Note that a mixture of two or more types of EVOH having different ratios of ethylene units may be used.

[0059] Further, as long as the effects of the present invention can be obtained, EVOH may contain a small amount of another monomer as a copolymer component. Examples of such a monomer include α-olefins such as propylene, 1-butene, isobutene, 4-methyl-1-pentene, 1-hexene, and 1-otene; itaconic acid, methacrylic acid, acrylic acid, and maleic anhydride. Unsaturated carboxylic acids such as acids and derivatives thereof; silane compounds such as butyltrimethoxysilane, butyltriethoxysilane, butyltri (methoxy-ethoxy) silane, and γ-methacryloxypropyltrimethoxysilane; unsaturated sulfonic acid or Salts thereof; alkylthiols; and bulpyrrolidones. When EVOH contains 0.0002 to 0.2 mol% of the silane compound as a copolymer component, it is easy to produce a homogeneous molded product when molding is performed by coextrusion molding or coinjection molding. As the silane compound, vinyltrimethoxysilane and butyltriethoxysilane are preferably used. [0060] A boron compound may be added to EVOH. This facilitates production of a homogeneous molded product when molding is performed by co-extrusion molding or co-injection molding. Examples of the boron compound include boric acids (for example, orthoboric acid), borate esters, borate salts, and borohydrides. Further, an alkali metal salt (eg, sodium acetate, potassium acetate, sodium phosphate) may be added to EVOH. This may improve the interlayer adhesion and compatibility in some cases. Further, a phosphoric acid conjugate (eg, sodium dihydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate, and dihydrogen hydrogen phosphate) may be added to EVOH. This may improve the thermal stability of EVOH in some cases. EVOH to which a boron compound, an alkali metal salt, and a phosphorus compound are added, and an ivy additive can be produced by a known method.

[0061] The type of polyamide resin is not particularly limited. For example, polycaprolamide (nylon 6), polydecaneamide (nylon 11), polylauryl ratatam (nylon 12), polyhexamethylene adipa Aliphatic polyamide homopolymers such as amide (nylon 6, 6) and polyhexamethylene sebacamide (nylon 6, 12); Kyprolonatam Z-lau mouth lactam copolymer Kylon — 6Z12), Kyokuprolatatam Z aminoundecane Acid copolymer (nylon 6Z11), Proproratam Ζω Aminononanoic acid copolymer (Nylon 6Z9), Proproratam タ hexamethylene azinamide copolymer (nylon 6Ζ6, 6), Proproratatam Ζhexamethylene adipamide Ζ Aliphatic polyamide copolymers such as hexamethylene sebacamide copolymer (nylon 6-6, 6/6, 10); polymethaxylylene adipamide (MX ), Hexamethylene isophthalamide copolymer hexamethylene terephthalamide Taramido Z (aromatic poly amide nylon 6TZ6I) such like to. These polyamide resins can be used alone or in combination of two or more. Of these, polycaprolamide (nylon 6) and polyhexamethylene adipamide (nylon 6, 6) are preferred.

[0062] Examples of the polyacrylonitrile-based resin include a homopolymer of acrylonitrile and a copolymer of acrylonitrile with a monomer such as acrylate ester.

[0063] The composition of Embodiment 3 includes an antioxidant, a plasticizer, a heat stabilizer (melt stabilizer), a photoinitiator, a deodorant, an ultraviolet absorber, an antistatic agent, as long as the effects of the present invention can be obtained. Agents, lubricants, colorants, fillers, fillers, pigments, dyes, processing aids, flame retardants, antifoggants, and desiccants And may contain at least one of the additives.

[0064] As the heat stabilizer (melt stabilizer), for example, one or two or more of a talcite ligated product at the mouth and a metal salt of a higher aliphatic carboxylic acid (for example, calcium stearate / magnesium stearate) are used. be able to. By using these compounds, it is possible to prevent the occurrence of gels and fish eyes during the production of the composition.

[0065] Examples of the deodorant include a zinc compound, an aluminum compound, a silicon compound, an iron (II) compound, and organic acids.

[0066] The composition of the present invention can be formed by mixing an oxygen absorber, a resin, and an additive with one component. The method of mixing the components and the order of mixing are not particularly limited. For example, all 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. Further, the additive and the resin may be mixed and then mixed with the oxygen absorbent. Specific methods for mixing include, for example, dissolving each component in a solvent to prepare a plurality of solutions, mixing these solutions and evaporating the solvent, and adding another component to the molten resin. Is added and kneading is performed.

[0067] The kneading can be performed using, for example, a ribbon blender, a high-speed mixer, a co-kneader, a mixing roll, an extruder, or an intensive mixer.

[0068] 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. In addition, the composition of the present invention may be molded as pellets and may be directly molded by dry blending the components of the composition.

[0069] In the oxygen-absorbing composition of the present invention, the start of oxygen absorption can be controlled by controlling the irradiation of light (particularly, ultraviolet light).

(Embodiment 4)

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

[0071] The composition of Embodiment 3 may be formed into a shape such as a film, a sheet, and a pipe by, for example, a melt extrusion molding method. Further, it may be formed into a container shape by an injection molding method. Further, the hollow container may be formed into a hollow container 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.

[0072] The packaging material of Embodiment 4 may be composed of only a layer made of the composition of Embodiment 3 (hereinafter, layer (A) t, which may be used), but a layer made of another material ( Hereinafter, it may be referred to as a layer (B)). By forming a laminate, properties such as mechanical properties, water vapor barrier properties, and oxygen noria properties can be further improved. The material and number of layers (B) are selected according to the properties required for the packaging.

[0073] The structure of the laminate 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 the two may be arranged. The configuration of the laminate is, for example, layer (A) Z layer (B), layer (B) Z layer (A) Z layer (B), layer (A) Z layer (C) Z layer (B), layer ( B) Z layer (C) Z layer (A) Z layer (C) Z layer (B), layer (B) Z layer (A) Z layer (B) Z layer (A) Z layer (B), and layer (B) Z layer (C) Z layer (A) Z layer (C) Z layer (B) Z layer (C) Z layer (A) Z 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 total thickness of the laminate in the range of 2 to 20%, it may be advantageous in terms of moldability and cost.

[0074] The layer (B) can be formed of, for example, a thermoplastic resin or metal. Examples of the metal used for the layer (B) include steel and aluminum. The resin used for the layer (B) is not particularly limited. For example, the resin exemplified for the layer (A) can be used. For example, polyolefins such as polyethylene, polypropylene, poly 4-methylenol 1 pentene, and poly 1-butene may be used. Further, an ethylene propylene copolymer, polyvinylidene chloride, polyvinyl chloride, polystyrene, polyacrylonitrile, polycarbonate, polyacrylate, or ethylene butyl alcohol copolymer may be used. Further, a polyester such as polyethylene terephthalate, polybutylene terephthalate, or polyethylene naphthalate may be used. In addition, polycaprolamide, polyhexamethylene adipamide, A polyamide such as silylene adipamide may 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-otene; unsaturated carboxylic acids such as itaconic acid, methacrylic acid, acrylic acid, and maleic anhydride. Acid, its salts, its partial or complete esters, its -tolyl, its amides, its anhydrides; formic acid bur, bur acetate, bur propionate, burbutyrate, burotatanoate, burddecanoate, burstearate Examples include carboxylic acid bur esters such as burarachidonate; bur silane compounds such as bur trimethoxy silane; unsaturated sulfonates or salts thereof; alkyl thiols; and bul pyrrolidones.

[0075] The layer (Α) and the layer (Β) may be unstretched, or may be uniaxially or biaxially stretched or rolled! /.

[0076] 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 or polyester-based one-pack or two-pack curable adhesives, copolymers or graft-modified unsaturated carboxylic acids or their anhydrides (such as maleic anhydride) to olefin-based polymers (carboxylic acid-modified) Polyolefin resin) can be used. When the layer (Α) and the layer (Β) contain a polyolefin resin, high adhesiveness can be realized by using a carboxylic acid-modified polyolefin resin. Examples of the carboxylic acid-modified polyolefin resin include carboxylic acid-modified polymers such as polyethylene, polypropylene, copolymerized polypropylene, ethylene butyl acetate copolymer, and ethylene (meth) acrylate ester copolymer. Fats and oils.

[0077] A deodorant may be added to at least one of the layers constituting the laminate. As the deodorant, for example, the deodorant exemplified in Embodiment 3 can be used.

[0078] The method for producing the laminate of Embodiment 4 is not particularly limited, and can be formed, for example, by a known method. For example, methods such as extrusion lamination, dry lamination, solvent casting, co-injection molding, and co-extrusion molding can be applied. As the coextrusion molding method, for example, a coextrusion laminating 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, the composition of the third embodiment By arranging a layer near the inner surface of the container, for example, the innermost layer, it becomes possible to quickly absorb oxygen in the container.

[0080] Among the multilayer containers, the present invention is suitably used for a multilayer container having a total thickness of 300 m or less, or a multilayer container manufactured by an extrusion blow molding method.

[0081] A multilayer container having a total thickness of 300 m or less is a container having a relatively thin multilayer structure such as a multilayer film, and is usually used in the form of a voucher or the like. It is flexible, easy to manufacture, has excellent gas barrier properties, and has a continuous oxygen absorption function, making it extremely useful for packaging products that are sensitive to oxygen and easily deteriorate. By setting the total thickness to 300 / zm or less, high flexibility can be obtained. By setting the thickness of all layers to 250 μm or less, especially 200 μm or less, higher flexibility can be obtained. In consideration of mechanical strength, the total thickness is preferably at least 10 m, more preferably at least 20 m.

[0082] In order to seal such a multilayer container, at least one surface layer of the multilayer film is preferably a layer made of a heat sealable resin. Examples of such a resin include polyolefins such as polyethylene and polypropylene. The multi-layer container is obtained by filling the contents into a bag-shaped multi-layer film and heat sealing.

[0083] 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 sensitive to oxygen and easily deteriorate.

[0084] The thickness of the body of the bottle-shaped 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 composed of the composition of the second embodiment can be, for example, in the range of 211 to 200 μm.

[0085] The packaging material of the present invention may be a packing (gasket) for a container, particularly a gasket for a cap of a container. In this case, a gasket is formed by the composition of the third embodiment.

[0086] Hereinafter, the present invention will be described in more detail with reference to Examples. [Example 1]

Example 1 shows the result of evaluating the oxygen absorbing ability of the light absorber of the present invention. In Example 1, P-25 (including 73.5% of anatase type and 26.5% of rutile type) manufactured by Nippon Aerosil Co., Ltd. was used as the titanium dioxide powder.

[0088] (Sample 1)

2. OOg of succinic acid and 18.00 g of titanium dioxide powder were mixed in a mortar to obtain a mixture. The mixture was stirred for 6 hours while heating to about 102 ° C to 106 ° C under a nitrogen stream (about 100 mlZ). Next, it was dried under reduced pressure. Thus, a titanium dioxide powder to which succinic acid was chemically adsorbed (sample 1) was produced.

[0089] (Sample 2)

8. 433 g of the above sample 1 and 84 mL of tetrahydrofuran (THF) were mixed, stirred at room temperature for 1 hour, suction-filtered, and the obtained powder was dried under reduced pressure. Thus, Sample 2 was obtained by washing Sample 1. The succinic acid content in the filtrate of the suction filtration was 0.592 g. Therefore, succinic acid adsorbed on the powder of Sample 2 was about 3% by weight of the entire powder of Sample 2.

[0090] (Sample 3)

1. OOg of succinic acid was dissolved in 100 mL of THF, 9. OOg of titanium dioxide powder was added, and the mixture was stirred at room temperature for 2 hours. This liquid was subjected to suction filtration, and the obtained powder was dried under reduced pressure. Thus, succinic acid-adsorbed titanium dioxide powder (sample 3) was obtained. The succinic acid content in the filtrate obtained by suction filtration was 0.564 g. Therefore, succinic acid adsorbed on the powder of sample 3 was about 4.4% by weight of the entire powder of sample 3.

[0091] (Sample 4)

The powder of Sample 3 was washed in the same manner as in Sample 2 to obtain a powder of Sample 4. The succinic acid adsorbed on the powder of the sample 4 is used as about 2% by weight of the entire powder of the sample 4.

(Preparation and Evaluation of Oxygen Absorbent)

0.5 g of each of the above four types of samples was placed in a 85 cc capacity bottle in a room at 23 ° C and 50% RH, and the bottle was sealed. The bottle is exposed to ultraviolet light. It was stored at 23 ° C in a state, and the oxygen absorption amount of the oxygen absorbent was calculated by measuring the oxygen concentration in the bottle after a certain period of time. A high-pressure mercury lamp (400 W) manufactured by Riko Kagaku Sangyo Co., Ltd. was used for ultraviolet irradiation. Figure 1 shows the evaluation results.

[0093] The vertical axis in Fig. 1 shows the amount of oxygen absorbed per oxygen absorbent lg. As is evident from FIG. 1, all of Samples 1-4 showed oxygen absorption capacity. However, as shown in the results of Sample 4, the properties of Sample 3 prepared without heat treatment were significantly reduced by washing. On the other hand, as shown in the results of Sample 2, the properties of Sample 1 prepared by heat treatment were small even after washing. Therefore, when compared after washing, the oxygen absorption capacity of sample 2 was higher than that of sample 4. It is considered that the reason why the decrease in the oxygen absorption capacity due to the washing in Sample 2 is small is that more succinic acid is chemically adsorbed in the titanium dioxide powder of Sample 1.

[0094] Further, as a comparative example, when only the titanium dioxide powder was used and the amount of oxygen absorption was measured, it was found that almost no oxygen was absorbed.

[0095] In addition, when Sample 1 was stored under the conditions without irradiating ultraviolet light and the amount of oxygen absorption was measured, the sample showed almost no oxygen absorption. From this, it was a component that the oxygen absorbent of the present invention can control the start of oxygen absorption by light irradiation.

[0096] (Infrared absorption spectrum measurement)

The infrared absorption spectrum of the samples 13 to 13 was measured by the ATR method. Figure 2 shows the measurement results. As shown in FIG. 2, 1650cm- ¹ - difference at the peak of 1800cm around ¹ was found seen.

[0097] The reason why the oxygen absorption capacity and infrared absorption spectrum of Samples 14 to 14 are different is not clear at present, but it is considered that the adsorption amount and adsorption state of succinic acid differ depending on the treatment method. Can be

[Example 2]

In Example 2, an evaluation was made on an oxygen absorbent using the alkoxysilane conjugate represented by the following formula (1) as the organic compound (A). [0099] [Formula 1]

[0100] The compound of the formula (1) was produced by the following method. First, 50 mL of ethanol and 30.4 g (0.3 mol) of triethylamine were poured into a three-necked flask having an inner volume of 100 mL. While cooling this mixture on ice, 24.4 g (0.1 mol) of 2- (4-cyclohexyl-ruethyl) trichlorosilane was added dropwise, and the mixture was cooled for 1 hour under ice-cooling, 1 hour at room temperature, and further at 40 ° C. For 3 hours. Thereafter, the precipitated hydrochloride was removed by filtration. Next, ethanol was distilled off under reduced pressure, followed by distillation under reduced pressure to obtain 17.lg of the compound of the formula (1).

[0101] The oxygen absorbent was produced by the following method. First, 1.916 g of the alkoxysilane conjugate of the formula (1) was dissolved in THF100 mL, and 17.244 g of titanium dioxide powder was further added thereto. Then, in a light-shielded state, THF was distilled off under stirring at 40 ° C. under reduced pressure. Next, the obtained powder was heated at 150 ° C. for 2 hours in an oil bath, allowed to cool, and further dried under vacuum. Thus, an oxygen absorbent (sample 5) was obtained. 0.5 g of the obtained oxygen absorbent was put into a bottle having a capacity of 85 cc in a room at 23 ° C. and 50% RH, and the bottle was sealed. Then, the bottle was stored at 23 ° C. in a state irradiated with a fluorescent lamp, and the oxygen absorption amount of the oxygen absorbent was measured by measuring the oxygen concentration in the bottle at regular intervals. As a result, the prepared oxygen absorbent showed an oxygen absorption of 0.7 ccZg in one day and 1.4 ccZg in five days.

[0102] [Example 3]

In Example 3, evaluation was made on an oxygen absorbent using dimethyl succinate as the organic compound (A).

[0103] The oxygen absorbent was produced by the following method. First, 2. OOg of dimethyl succinate and 18. OOg of titanium dioxide powder were mixed in a mortar to obtain a mixture. The mixture was stirred for 6 hours while heating to about 102 ° C to 106 ° C under a nitrogen stream (about 100 mlZ). Next, it was dried under reduced pressure. In this manner, succinic acid chemically adsorbed titanium dioxide powder (sample 6) was prepared. Made. 0.5 g of the obtained sample was put into a 85 cc capacity bottle at 23 ° C. in a 50% RH room, and the bottle was sealed. Then, the bottle was stored at 23 ° C. in a state where it was irradiated with ultraviolet light, and the oxygen concentration of the oxygen absorbent was calculated by measuring the oxygen concentration in the bottle after a certain period of time. Figure 3 shows the evaluation results.

[Example 4]

Example 4 describes an example in which a press film made of the oxygen-absorbing composition was produced.

[0105] (Sample 7)

First, the oxygen absorbent (sample 5) described in Example 2 was produced. Next, 90 parts by weight of EVOH and 10 parts by weight of Sample 5 were mixed and melt-blended for 5 minutes. The blending was performed under a nitrogen atmosphere with the light blocked. Then, the obtained mixture was pressed with a compression molding machine to a thickness of about 100 μm to produce a press film (Sample 7).

[0106] (Sample 8)

An oxygen absorbent was produced in the same manner as in Sample 5, except that a compound represented by the following formula (2) (obtained from Tokyo Chemical Industry Co., Ltd.) was used instead of the alkoxysilane conjugate.

[0107] [Formula 2]

[0108] Next, a press film (sample 8) was produced in the same manner as in sample 7, except that this oxygen absorbent was used instead of sample 5.

[0109] (Evaluation of oxygen absorption capacity)

For each of Samples 7 and 8, 0.5 g was charged into a bottle having a capacity of 85 cc in a room at 23 ° C. and 50% RH, and the bottles were sealed. Then, the bottle was stored at 23 ° C under irradiation of a fluorescent lamp, the oxygen concentration in the bottle after a certain period of time was measured, and the oxygen absorption of the press film was evaluated. Figure 4 shows the evaluation results. As shown in FIG. 4, Samples 7 and 8 both exhibited high! ヽ oxygen absorption capacity. [Example 5]

In Example 5, another example in which a press film made of the oxygen-absorbing composition was produced will be described.

[0111] First, the oxygen absorbent (sample 1) described in Example 1 was produced. Next, 90 parts by weight of EVOH and 10 parts by weight of Sample 1 were mixed and melt-blended for 5 minutes. The blending was performed under a nitrogen atmosphere with the light blocked. Then, the obtained mixture was pressed with a compression molding machine to a thickness of about 100 μm to produce a press film (Sample 9).

[0112] (Evaluation of oxygen absorption capacity)

0.5 g of Sample 9 was placed in an 85 cc bottle in a room at 23 ° C and 50% RH, and the bottle was closed. Then, the bottle was stored at 23 ° C under irradiation with a fluorescent lamp, the oxygen concentration in the bottle after a certain period of time was measured, and the oxygen absorption amount of the press film was evaluated. Figure 5 shows the evaluation results. As shown in FIG. 5, Sample 9 exhibited high oxygen absorption capacity.

[0113] (Evaluation of oxygen absorption ability by UV irradiation)

0.5 g of Sample 9 was placed in an 85 cc bottle in a room at 23 ° C and 50% RH, and the bottle was closed. Then, this bottle was stored at 23 ° C. in a state where it was irradiated with ultraviolet light, and the oxygen absorption amount of the press film was evaluated by measuring the oxygen concentration in the bottle after a certain period of time. Figure 6 shows the evaluation results. As shown in FIG. 6, Sample 9 showed high oxygen absorption capacity.

[0114] Although the present invention has been described above, the present invention is not limited to the above embodiment, and can be applied to other embodiments based on the technical idea of the present invention.

Industrial applicability

[0115] The present invention can be applied to oxygen absorbers, oxygen-absorbing compositions, and packaging materials using them. In particular, it is suitably used as an article which is greatly affected by deterioration due to oxygen, for example, as a packaging material for food, medicine, medical equipment, machine parts, clothing and the like.

Claims

The scope of the claims

[I] An oxygen absorbent containing particles functioning as a photocatalyst and an organic compound chemically adsorbed on the surface of the particles.

2. The oxygen absorbent according to claim 1, wherein the organic compound is an organic compound formed by a reaction between an organic compound (A) containing a functional group that reacts with a hydroxyl group and a hydroxyl group on the surface of the particle. .

[3] The oxygen absorbent according to claim 2, wherein the particles contain titanium dioxide.

4. The oxygen absorber according to claim 3, wherein the titanium dioxide is an anatase-type titanium dioxide.

[5] The oxygen absorbent according to claim 2, wherein the organic compound (A) is at least one compound selected from the group consisting of a carboxylic acid, an ester, an aldehyde, an alkoxysilane derivative and an amine.

[6] The oxygen absorbent according to claim 1, wherein the formula weight of the organic compound is 3000 or less.

[7] The oxygen absorbent according to claim 6, wherein the organic compound (A) is succinic acid.

[8] A method for producing an oxygen absorbent, which comprises a step of adsorbing an organic compound on the surface of particles functioning as a photocatalyst.

9. The method for producing an oxygen absorbent according to claim 8, wherein the particles have a hydroxyl group on the surface, and the organic compound contains a functional group that reacts with the hydroxyl group.

10. The method for producing an oxygen absorbent according to claim 9, wherein the organic compound is at least one compound selected from the group consisting of a carboxylic acid, an ester, an aldehyde, an alkoxysilane derivative, and an amine.

[II] The method for producing an oxygen absorbent according to claim 9, wherein the particles include titanium dioxide.

[12] (i) a step of preparing a mixture containing the organic compound, the particles, and an organic solvent;

9. The method for producing an oxygen absorbent according to claim 8, comprising (ii) removing the organic solvent from the mixture.

13. The method for producing an oxygen absorbent according to claim 12, comprising a step of heating the mixture from which the organic solvent has been removed at a temperature equal to or higher than the boiling point of water.

[14] (I) a step of preparing a mixture containing the organic compound and the particles, 9. The method for producing an oxygen absorbent according to claim 8, comprising: (II) a step of chemically adsorbing the organic compound to the particles by heating the mixture.

15. The method for producing an oxygen absorbent according to claim 14, wherein the step (ii) includes a step of heating the mixture at a temperature equal to or higher than the boiling point of water.

16. The method for producing an oxygen absorbent according to claim 13, wherein the mixture is heated under a nitrogen atmosphere or under reduced pressure.

[17] An oxygen absorbent produced by the production method according to claim 8.

[18] An oxygen-absorbing composition comprising a resin and an oxygen absorbent dispersed in the resin, wherein the oxygen absorbent is the oxygen absorbent according to claim 1.

[19] The oxygen-absorbing composition according to claim 18, wherein the resin contains an ethylene butyl alcohol copolymer.

[20] A packaging material including a portion comprising the oxygen-absorbing composition according to claim 18.