JP4865542B2 - 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 using titanium dioxide have been disclosed (for example, JP-A-7-316342, JP-A-11-12115, JP-A-11-278845, JP-A-11-278845). 2000-86415, JP 2000-316547, JP 2000-344958, JP 2001-226207, JP 2002-320917).

  However, conventionally proposed oxygen absorbents have a problem of poor dispersibility when dispersed in a polymer. Further, there is a problem that the performance is greatly lowered when dispersed in a polymer.

  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 particles functioning as a photocatalyst and an organic compound (organic group) chemically adsorbed on the surface of the particles.

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

  In the oxygen absorbent of the present invention, the particles may contain titanium dioxide. In the oxygen absorbent of the present invention, the titanium dioxide may be anatase type titanium dioxide.

  In the oxygen absorbent of the present invention, the organic compound (A) may be at least one compound selected from the group consisting of carboxylic acids, esters, aldehydes, alkoxysilane derivatives, and amines. 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 α-position of a carbonyl group or an α-position of an ethylenic double bond ( Organic compounds having a methylene group at the allylic position are preferred. 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 organic compound (A) may be succinic acid.

  In addition, the method of the present invention for producing an oxygen absorbent includes a step of chemically adsorbing an organic compound on the surface of particles functioning as a photocatalyst.

  In the said manufacturing method, the said particle | grain may have a hydroxyl group on the surface, and the said organic compound may contain the functional group which reacts with a hydroxyl group.

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

  In the manufacturing method, the particles may contain titanium dioxide.

  The manufacturing method may include (i) a step of preparing a mixture including the organic compound, the 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 from which the organic solvent has been removed at a temperature equal to or higher than the boiling point of water may be included.

  The manufacturing method may include (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. . 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 above production method, the mixture may be heated under a nitrogen atmosphere or under reduced pressure.

  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 containing a resin and an oxygen absorbent dispersed in the resin, and the oxygen absorbent is the oxygen absorbent of the present invention. . In this oxygen-absorbing composition, the resin may contain an ethylene-vinyl alcohol copolymer.

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

  Since the oxygen absorbent of the present invention is in the form of particles, it can be easily dispersed uniformly in the resin. Moreover, in the oxygen absorbent of this invention, since the organic compound to be oxidized is chemisorbed on the photocatalyst particles, it exhibits a high oxygen absorption ability. Since the oxygen absorbent of the present invention is activated by light irradiation, the timing and intensity of the oxygen absorption ability can be controlled by controlling the time and amount of light irradiation. Moreover, since the expression of oxygen absorption ability can be suppressed by preventing light irradiation, storage and the like are easy.

  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 the photocatalyst 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. 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, 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 absorbing ability of the oxygen absorbent of the present invention and the comparative oxygen absorbent. 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 another example of the oxygen absorbing ability of the oxygen absorbent of the present invention. FIG. 4 is a graph showing another example of the oxygen absorbing ability of a press film made of the oxygen-absorbing composition of the present invention. FIG. 5 is a graph showing another example of the oxygen absorbing ability of a press film made of the oxygen-absorbing composition of the present invention. FIG. 6 is a graph showing another example of the oxygen absorption capacity of 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. Further, the exemplified materials 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 particles functioning as a photocatalyst (hereinafter referred to as photocatalyst particles) and an organic compound (organic group) chemically adsorbed on the photocatalyst particles. The organic compound chemically adsorbed on the photocatalyst particles may be an organic compound that is oxidized by the catalytic action of the photocatalyst particles. This organic compound is formed by the reaction of an organic compound containing a functional group that reacts with the surface of the photocatalyst particles (hereinafter sometimes referred to as organic compound (A)) with the surface of the photocatalyst particles. The ratio of the photocatalyst particles and the organic compound (A) adsorbed to 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 100 parts by weight of the photocatalyst particles may be in the range of 1 to 100 parts by weight, and is preferably 1 to 10 parts by weight.

  The average particle diameter of the photocatalyst particles is not particularly limited, but is preferably 1000 nm or less, and more preferably 500 nm or less. By setting the average particle size of the photocatalyst particles to 1000 nm or less, the photocatalytic function can be improved by increasing the surface area. Moreover, the dispersibility to a polymer | macromolecule can be improved by making an average particle diameter 1000 nm or less, and transparency can be provided.

  Examples of the material for the photocatalyst particles include titanium dioxide, tungsten oxide, zinc oxide, cerium oxide, strontium titanate, and potassium niobate. Among these, since the photocatalytic function is high, it is recognized as a food additive and is safe and inexpensive, it is preferable that the photocatalyst particles contain titanium dioxide, and particles composed solely of titanium dioxide are typically used. .

  When the photocatalyst particles are titanium dioxide particles, the particles are preferably anatase type titanium dioxide, and 30% by weight or more (more preferably 50% by weight or more) of the titanium dioxide powder (the whole particle) is anatase type titanium dioxide. Preferably there is. By using anatase type titanium dioxide particles, a high photocatalytic action can be obtained.

  The photocatalyst particles preferably have a functional group on the surface, and particularly preferably have a hydroxyl group. A typical example of such photocatalytic particles is titanium dioxide particles.

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 and the hydroxyl group react to form an organic compound that is chemically adsorbed on the photocatalyst particle. 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, as the organic compound (A), for example, at least one compound selected from the group consisting of carboxylic acids, esters, aldehydes, alkoxysilane derivatives, and amines can be used. Such an organic compound (A) is more efficiently oxidized by oxide ions (O ²⁻ ) and hydroxyl radicals (OH) than hydrocarbons having no functional group that reacts with the surface of the photocatalyst particles. Is done. The carboxylic acid may be in the form of a salt. Moreover, higher oxygen absorption ability may be obtained by using a compound containing a carbon-carbon double bond as the organic compound (A).

  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 photocatalyst 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 photocatalyst particle through the -C-O- moiety thereof. Moreover, when the functional group to react is an alkoxy silyl group, it couple | bonds with photocatalyst particle | grains in the part of -Si-O-. Moreover, when the functional group to react is an amino group, it couple | bonds with photocatalyst particle | grains by the nitrogen part.

  The organic compound (A) only needs to be oxidized by irradiating the photocatalyst particles with light. 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, high oxygen absorption ability can be obtained, and generation of low molecular compounds due to oxidation of organic compounds can be suppressed.

  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, glutaric acid, adipine Saturated aliphatic dicarboxylic acids such as acids and sebacic acids; unsaturated aliphatic carboxylic acids such as acrylic acid, propiolic acid, methacrylic acid, crotonic acid, oleic acid, maleic acid, and fumaric acid; aromatics such as benzoic acid, phthalic acid, and terephthalic acid Carboxylic acid is mentioned. Among these, when succinic acid is used, an effect that oxidation by a photocatalyst proceeds efficiently can be obtained.

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

  Moreover, as a typical aldehyde applicable as the organic compound (A), for example, acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, valeraldehyde, isovaleraldehyde, hexanal, octanal, 7-octenal, nonanal, decanal, crotonaldehyde , Senescence aldehyde, acrolein, methacrolein, nonane dial and the like.

  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, methylamine, ethylamine, propylamine, isopropylamine, butylamine, isobutylamine, secondary butylamine, tertiary butylamine, amylamine, isoamylamine, and tertiary amylamine. , 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, 1 8-diamino octane, 1,9-diaminononane and 1,10-diaminodecane and the like.

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

  In the oxygen absorbent according to Embodiment 1, it is important that the organic compound is chemisorbed (chemically bonded) to the surface of the photocatalyst 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, since the organic compound is chemically adsorbed on the surface of the photocatalyst particle in the oxygen absorbent of the present invention, the following effects can be obtained compared to the conventional oxygen absorbent in which the organic compound is not chemisorbed on the photocatalyst particle. It is done. (1) Unlike the case of physical adsorption, bleed-out hardly occurs even when dispersed in a resin. (2) The organic compound (A) can be prevented from volatilizing from the vacuum vent when blended with the resin. (3) Since the released organic compound is decomposed when blended with the resin, it is preferable to wash the oxygen absorbent before blending, but unlike the case of physical adsorption, the organic compound (A) is washed. Can be prevented from falling off the surface of the photocatalyst particles. (4) When compared after washing, the oxygen absorption capacity is higher by chemical adsorption than in physical adsorption. (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. The oxygen absorbent produced by this method is one of the oxygen absorbents of the present invention.

  The production method of the present invention includes a step of chemically 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.

  Below, two examples are given and demonstrated about the manufacturing method of this invention.

  In the first method, first, a mixture of an organic compound (A), photocatalyst particles, and an organic solvent is prepared (step 1a). The organic solvent only needs to be capable of uniformly dispersing or dissolving 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, ethyl acetate, and the like. Among these, by using hexane, toluene or the like, water generated when the organic compound (A) reacts with the hydroxyl group on the photocatalyst particle surface 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), the photocatalyst particles, and the organic solvent, there are cases where a part of the organic compound (A) can be chemically adsorbed to the photocatalyst particles by the step 2a.

  In the second method, first, a mixture containing the organic compound (A) and photocatalyst particles is prepared (step 1b). Next, the organic compound (A) is chemically adsorbed on the photocatalyst particles by heating the mixture (step 2b). In the second method, the organic compound (A) and the photocatalyst particles are usually mixed without using a solvent.

  When the 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, 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. preferable. 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 proportion of the organic compound (A) that is chemically adsorbed 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, it is preferable that the process 2a and the process 2b include the process heated at the temperature more 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 first, 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.

  It is preferable to perform the said process in the state which interrupted | blocked light (especially ultraviolet light). By performing the above process in a state where light is blocked, it is possible to prevent the performance of the oxygen absorbent from being deteriorated.

  According to the manufacturing method of Embodiment 2, the oxygen absorbent containing the photocatalyst particles in which the organic compound (A) is chemisorbed (chemically bonded) is obtained. In addition, the oxygen absorbent of the present invention (the oxygen absorbent of Embodiments 1 and 2) may be used alone or may be used by being dispersed in a resin or the like.

  In the oxygen absorbent according to the present invention, when irradiated with light, the organic compound is oxidized and exhibits oxygen absorbing ability. Therefore, it is preferable to prevent the organic compound adsorbed on the photocatalyst particles from being oxidized before the start of use by light irradiation. For this reason, in the oxygen absorbent of the present invention, it is important to prevent light (particularly ultraviolet light) from being irradiated before the start of use. When light is not irradiated before the start of use, the organic compound is not oxidized and the photocatalyst particles are not significantly changed. For example, when the photocatalyst particles are titanium dioxide particles, the amount of oxygen defects in the titanium dioxide particles before the start of use is preferably substantially the same as that before the organic compound is adsorbed. Specifically, before the start of use, the amount of oxygen atoms contained in the titanium dioxide particles after adsorbing the organic compound is 95 atoms of the amount of oxygen atoms contained in the titanium dioxide particles before adsorbing the organic compound. % Or more (preferably 99 atomic% or more).

(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.

  The amount of the oxygen absorbent contained in the composition of Embodiment 3 is not particularly limited and is adjusted according to the purpose. In the composition of an example, the amount of the oxygen absorbent can be in the range of 1 to 30 parts by weight, more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the resin.

  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 a high oxygen barrier property, a composition suitable for a material of a packaging material of an article 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 the polyvinyl alcohol-based resins, an ethylene-vinyl alcohol copolymer (hereinafter sometimes referred to as EVOH) has characteristics that it can be melt-molded and has 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, 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. 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.

  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)
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 resin used for a layer (B) is not specifically limited, For example, resin illustrated about a 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 having evaluated the oxygen absorption ability of the light absorber of this invention is shown. In Example 1, P-25 manufactured by Nippon Aerosil Co., Ltd. (including 73.5% anatase type and 26.5% rutile type) was used as the titanium dioxide powder.

(Sample 1)
A mixture was obtained by mixing 2.00 g of succinic acid and 18.00 g of titanium dioxide powder in a mortar. This mixture was stirred for 6 hours under a nitrogen stream (about 100 ml / min) while being heated to about 102 ° C. to 106 ° C. Next, it was dried under reduced pressure. In this way, titanium dioxide powder (sample 1) to which succinic acid was chemically adsorbed was produced.

(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 resulting powder was dried under reduced pressure. In this way, Sample 1 was washed to obtain Sample 2. In addition, it was 0.592g when the succinic acid in the filtrate of suction filtration was measured. Therefore, the succinic acid adsorbed on the powder of sample 2 was about 3% by weight of the whole powder of sample 2.

(Sample 3)
1.00 g of succinic acid was dissolved in 100 mL of THF, 9.00 g 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. In this way, titanium dioxide powder (sample 3) on which succinic acid was adsorbed was obtained. The amount of succinic acid in the filtrate of the suction filtration was 0.564 g. Therefore, the succinic acid adsorbed on the powder of sample 3 was about 4.4% by weight of the total powder of sample 3.

(Sample 4)
Sample 3 powder was washed in the same manner as Sample 2 to obtain Sample 4 powder. The succinic acid adsorbed on the powder of sample 4 was about 2% by weight of the total powder of sample 4.

(Production and evaluation of oxygen absorber)
About 4 types of said samples, 0.5g was each injected | thrown-in to the bottle of 85 cc capacity | capacitance in the room | chamber interior of 50% RH at 23 degreeC, and the bottle was sealed. Then, this bottle was stored at 23 ° C. while being irradiated with ultraviolet light, and the oxygen concentration in the bottle was measured after a certain period of time to calculate the oxygen absorption amount of the oxygen absorbent. A high-pressure mercury lamp (400 W) manufactured by Riko Science and Technology Co., Ltd. was used for ultraviolet irradiation. 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 is clear from FIG. 1, Samples 1 to 4 all showed oxygen absorption ability. However, as shown in the results of Sample 4, the characteristics of Sample 3 produced without heat treatment were greatly deteriorated by washing. On the other hand, as shown in the results of Sample 2, Sample 1 produced by heat treatment showed little deterioration in properties even after washing. Therefore, when compared after washing, Sample 2 had a higher oxygen absorption capacity than Sample 4. The reason why the decrease in oxygen absorption capacity due to washing in sample 2 is small is considered to be because more succinic acid is chemisorbed in the titanium dioxide powder of sample 1.

  Further, as a comparative example, when only the titanium dioxide powder was used and the oxygen absorption amount was measured, the oxygen absorption was hardly exhibited.

  Moreover, when the sample 1 was stored under the conditions where ultraviolet light was not irradiated and the oxygen absorption amount was measured, it showed almost no oxygen absorption. From this, it was found that the oxygen absorbent of the present invention can control the start of oxygen absorption by light irradiation.

(Infrared absorption spectrum measurement)
About the said samples 1-3, the infrared absorption spectrum was measured by ATR method. The measurement results are shown in FIG. As shown in FIG. 2, it was observed differences peak near 1650cm ^-1 ~1800cm ^-1.

  The reason why the oxygen absorption capacity and infrared absorption spectrum of Samples 1 to 4 are different is not clear at present, but it is considered that the amount of succinic acid adsorbed and the state of adsorption differ depending on the treatment method.

[Example 2]
In Example 2, the oxygen absorbent using the alkoxysilane compound represented by the following formula (1) as the organic compound (A) was evaluated.

  The compound of formula (1) was prepared by the following method. First, 50 mL of ethanol and 30.4 g (0.3 mol) of triethylamine were added to a 3-neck flask having an internal volume of 100 mL. While cooling this mixture with ice, 24.4 g (0.1 mol) of 2- (4-cyclohexenylethyl) trichlorosilane was added dropwise, and the mixture was cooled with ice for 1 hour, at room temperature for 1 hour, and further at 40 ° C. for 3 hours. Reacted. Thereafter, the precipitated hydrochloride was removed by filtration. Next, after distilling off ethanol under reduced pressure, 17.1 g of the compound of formula (1) was obtained by distillation under reduced pressure.

  The oxygen absorbent was produced by the following method. First, 1.916 g of the alkoxysilane compound of the formula (1) was dissolved in 100 mL of THF, and 17.244 g of titanium dioxide powder was further added thereto. Then, in a light-shielded state, THF was distilled off while stirring at 40 ° C. under reduced pressure. Next, the obtained powder was heated in an oil bath at 150 ° C. for 2 hours, allowed to cool, and further vacuum dried. In this way, an oxygen absorbent (sample 5) was obtained. 0.5 g of the obtained oxygen absorbent 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 in the state irradiated with the fluorescent lamp, and the oxygen absorption amount of the oxygen absorbent was measured by measuring the oxygen concentration in a bottle for every fixed period. As a result, the produced oxygen absorbent exhibited oxygen absorption of 0.7 cc / g in 1 day and 1.4 cc / g in 5 days.

[Example 3]
In Example 3, the oxygen absorbent using dimethyl succinate as the organic compound (A) was evaluated.

  The oxygen absorbent was produced by the following method. First, 2.00 g of dimethyl succinate and 18.00 g of titanium dioxide powder were mixed in a mortar to obtain a mixture. This mixture was stirred for 6 hours under a nitrogen stream (about 100 ml / min) while being heated to about 102 ° C. to 106 ° C. Next, it was dried under reduced pressure. In this way, a titanium dioxide powder (sample 6) in which succinic acid was chemically adsorbed was produced. 0.5 g of the obtained sample was put into a bottle with a capacity of 85 cc in a 50% RH room at 23 ° C., and the bottle was sealed. Then, this bottle was stored at 23 ° C. while being irradiated with ultraviolet light, and the oxygen concentration in the bottle was measured after a certain period of time to calculate the oxygen absorption amount of the oxygen absorbent. The evaluation results are shown in FIG.

[Example 4]
In Example 4, an example of producing a press film made of an oxygen-absorbing composition will be described.

(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 in a nitrogen atmosphere while blocking light. 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.

(Sample 8)
An oxygen absorbent was produced in the same manner as 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 compound.

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

(Evaluation of oxygen absorption capacity)
About the said samples 7 and 8, 0.5g was each injected | thrown-in to the bottle of capacity | capacitance 85cc in the room | chamber interior of 50% RH at 23 degreeC, and the bottle was sealed. And the bottle was stored at 23 degreeC in the state irradiated with a fluorescent lamp, the oxygen concentration in the bottle after progress for a fixed period was measured, and the oxygen absorption amount of the press film was evaluated. The evaluation results are shown in FIG. As shown in FIG. 4, Samples 7 and 8 both showed high oxygen absorption capacity.

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

  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 in a nitrogen atmosphere while blocking light. And the obtained mixture was pressed to about 100 micrometers in thickness with the compression molding machine, and the press film (sample 9) was produced.

(Evaluation of oxygen absorption capacity)
0.5 g of Sample 9 was put into a bottle with a capacity of 85 cc in a 50% RH room at 23 ° C., and the bottle was sealed. And the bottle was stored at 23 degreeC in the state irradiated with a fluorescent lamp, the oxygen concentration in the bottle after progress for a fixed period was measured, and the oxygen absorption amount of the press film was evaluated. The evaluation results are shown in FIG. As shown in FIG. 5, Sample 9 showed a high oxygen absorption capacity.

(Evaluation of oxygen absorption capacity by UV irradiation)
0.5 g of Sample 9 was put into a bottle with a capacity of 85 cc in a 50% RH room at 23 ° C., and the bottle was sealed. And this bottle was stored at 23 degreeC in the state irradiated with the ultraviolet light, and the oxygen absorption amount of a press film was evaluated by measuring the oxygen concentration in the bottle after progress for a fixed period. The evaluation results are shown in FIG. As shown in FIG. 6, sample 9 showed a high oxygen absorption capacity.

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

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

Claims (20)

And particles that function as a photocatalyst, an organic compound chemically adsorbed on the surface of the particles a including oxygen absorber,
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,
An oxygen absorbent , wherein the organic compound (A) is at least one compound selected from the group consisting of dicarboxylic acids, esters of dicarboxylic acids, aldehydes having a cyclohexene ring, and alkoxysilane derivatives having a cyclohexene ring . The oxygen absorbent according to claim 1, wherein the particles include titanium dioxide. The oxygen absorbent according to claim 2, wherein the titanium dioxide is anatase type titanium dioxide. The oxygen absorbent according to any one of claims 1 to 3, wherein the organic compound (A) is a dicarboxylic acid . The oxygen absorber according to any one of claims 1 to 3, wherein the organic compound (A) is succinic acid. An oxygen absorbent comprising particles functioning as a photocatalyst and an organic compound chemisorbed on the surface of the particles,
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,
The organic compound (A) is an unsaturated compound containing an unsaturated bond adjacent to an unsubstituted methylene group, and at least one selected from the group consisting of carboxylic acids, esters, aldehydes, alkoxysilane derivatives, and amines. One compound, oxygen absorber. The oxygen absorbent according to claim 6, wherein the particles include titanium dioxide. A method for producing an oxygen absorbent comprising a step of chemically adsorbing an organic compound on the surface of particles functioning as a photocatalyst ,
The method for producing an oxygen absorbent, wherein the organic compound is at least one compound selected from the group consisting of dicarboxylic acids, esters of dicarboxylic acids, aldehydes having a cyclohexene ring, and alkoxysilane derivatives having a cyclohexene ring. The method for producing an oxygen absorbent according to claim 8, wherein the particles have a hydroxyl group on the surface. The method for producing an oxygen absorbent according to claim 8 or 9, wherein the organic compound is a dicarboxylic acid . The method for producing an oxygen absorbent according to any one of claims 8 to 10, wherein the particles contain titanium dioxide. (I) preparing a mixture comprising the organic compound, the particles and an organic solvent;
(Ii) The method for producing an oxygen absorbent according to any one of claims 8 to 11, comprising a step of removing the organic solvent from the mixture.   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. (I) preparing a mixture containing the organic compound and the particles;
(II) The method for producing an oxygen absorbent according to any one of claims 8 to 11, comprising a step of chemically adsorbing the organic compound onto the particles by heating the mixture.   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 a boiling point of water. The method for producing an oxygen absorbent according to any one of claims 13 to 15, wherein the mixture is heated under a nitrogen atmosphere or under reduced pressure. The oxygen absorber manufactured with the manufacturing method of any one of Claims 8-16 . 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 7 and 17 .   The oxygen-absorbing composition according to claim 18, wherein the resin contains an ethylene-vinyl alcohol copolymer. A packaging material comprising a portion made of the oxygen-absorbing composition according to claim 18 or 19 .