Oxygen absorber and resin composition

Abstract

The present invention aims to develop an oxygen absorber and a resin packaging material with oxygen absorption capacity that are colorless (white), odorless, do not react to metal detectors, are transparent even when blended with resin, and have oxygen absorption performance greater than that of iron powder. Solution: The following formula (1) TIFF0007765116000003.tif12134 (In the formula, M represents at least one selected from divalent Fe, Mn, and Co; A represents at least one n-valent organic acid and / or organic ligand (n is 0 or an integer ranging from 1 to 4); x and z each represent a value within the following ranges, 0

Description

[Technical Field]

[0001] The present invention relates to a novel inorganic oxygen absorber and an oxygen-absorbing resin composition containing the same. More specifically, the present invention relates to an oxygen absorber containing, as an active ingredient, a solid solution in which divalent white hydroxides of Mg and / or Ca are substituted with at least one element selected from divalent Fe, Mn, and Co, and to an oxygen-absorbing resin composition containing the same. [Background technology]

[0002] Foods, medicines, cosmetics, electronic components, etc. are subject to quality deterioration due to oxidation by oxygen in the air. As a countermeasure, oxygen absorbers are enclosed in the packaging. As oxygen absorbers, metal powder-based oxygen absorbers using metal powders such as Fe, Mn, Co, etc., especially iron powder, as the main reactive agent are commonly used from the viewpoints of non-toxicity, cost, and oxygen absorption capacity.

[0003] Metal powder (1), typified by iron powder, the most common oxygen absorber, has low oxygen absorption capacity on its own and requires moisture, so it is used in combination with an alkali metal halide or alkaline earth metal halide as an activator, and is packaged together with the packaged object, such as food, in a packaging material, such as a resin film. However, there are problems such as reaction to metal detectors used for foreign body inspection, ignition when used in a microwave oven, and being mistaken for food and accidentally ingested (Patent Document 1).

[0004] Inorganic oxygen absorbers, other than metal powder, include (2) sulfites, bisulfites, and dithionites, and (3) oxygen-deficient compounds such as cerium oxide and partially reduced titanium oxide. However, like metal powder, (2) requires moisture and has problems such as odor transfer to food and toxicity. (3) is expensive, has strong coloring, poor transparency, and low oxygen absorption capacity.

[0005] Organic oxygen absorbers include (4) L-ascorbic acid, sorbic acid and its salts, sugars such as glucose, reducing polyhydric alcohols such as catechol and pyrogallol, unmodified polybutadiene having an aliphatic unsaturated bond, and maleic anhydride-modified polybutadiene (Patent Document 2). Organic absorbers have lower oxygen absorption capacity than iron powder, and require the addition of moisture, alkali, transition metals, etc. Many of them have heat resistance lower than the resin processing temperature, and may foam when processed into a resin film.

[0006] Oxygen-absorbing resin compositions containing iron powder or the like are also known, but there are no colorless and transparent compositions (Patent Document 3). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 4-90848 [Patent Document 2] Japanese Patent Application Publication No. 2018-021128 [Patent Document 3] Japanese Patent Application Publication No. 11-080555 Summary of the Invention [Problem to be solved by the invention]

[0008] To provide a new oxygen absorber and a transparent oxygen-absorbing resin package which can reduce the oxygen concentration in a package to the same level as iron powder, is colorless (white), odorless, does not react to a metal detector, can be used in a microwave oven, and is colorless and transparent even when mixed with a resin. [Means for solving the problem]

[0009] The present invention relates to a compound represented by the following formula (1): [ka] (In the formula, M represents at least one selected from divalent Fe, Mn, and Co; A n-represents an n-valent [n is an integer in the range of 0 or 1 to 4] organic acid and / or organic ligand, and x and z are in the following ranges respectively: 0 < x < 0.3, preferably 0.01 ≤ x ≤ 0.2, particularly preferably 0.02 ≤ x ≤ 0.1, 0 ≤ z < 0.2, preferably 0.001 ≤ z ≤ 0.005, particularly preferably 0.002 ≤ z ≤ 0.002), an oxygen absorber containing a magnesium hydroxide-based solid solution and / or a calcium hydroxide-based solid solution as an active ingredient.

[0010] The inventor focused on the fact that the hydroxides of divalent Fe, Mn, and Co have weak coloring and are essential minerals. However, the hydroxides of divalent Fe, Mn, and Co have the problem of being extremely easily oxidized. A further problem is that dehydration decomposition starts at about 200°C or lower, so foaming occurs during the kneading and molding processes with resins and cannot be used for resins. As a result of intensively developing new materials to solve these problems, it was discovered that by dissolving at least one selected from divalent Fe, Mn, and Co in the hydroxides of Ca and / or Mg, which have high whiteness and high decomposition temperature, all problems can be solved.

[0011] The oxygen absorber of the present invention has the following characteristics. (A) Ca and Mg are essential minerals required in moderate amounts, and their hydroxides are substances with high safety approved as food additives. Divalent Fe, Mn, and Co are essential minerals required in trace amounts. Therefore, since the solid solution of formula (1) can be composed only of essential minerals, it has high safety and is suitable for resin materials for food packaging. (B) The hydroxides of divalent Fe, Mn, and Co are colored, but the solid solution of formula (1) is colorless or white to gray, and has high whiteness in the region where the solid solution amount is small. (C) Since the dehydration decomposition start temperature of the solid solution of formula (1) is about 250°C or higher, foaming during resin processing can be prevented. (D) The performance of the solid solution of formula (1) as an oxygen absorber is superior to that of iron powder in both oxygen absorption rate and capacity. Moreover, while iron powder requires the coexistence of moisture and a pro-oxidant such as sodium chloride to exhibit high oxygen absorption performance, the solid solution of formula (1) does not necessarily require a pro-oxidant. Even without the coexistence of moisture, oxidants, etc., its oxygen absorption performance is superior to that of iron powder. [Effects of the Invention]

[0012] The oxygen absorber of the present invention provides the following benefits: (1) Its oxygen absorption capacity is superior to that of existing oxygen absorbers. (2) It is possible to manufacture colorless and highly transparent resin packaging containers or bags, which allows the contents of the package to be visually confirmed. (3) It eliminates the labor and equipment required for filling and sealing highly breathable small pouches and co-packing these pouches with food, etc., which is currently required for mainstream oxygen absorbers. (4) It does not react to metal detectors used for foreign object inspection, improving the efficiency of packaging work. (5) Microwave ovens are available. [Brief explanation of the drawings]

[0013] [Figure 1] Oxygen absorption rate in glass containers DETAILED DESCRIPTION OF THE INVENTION

[0014] The crystal structure of the oxygen absorber of the present invention represented by formula (1) belongs to a hexagonal Cd(OH)2-type structure. The solid solution of formula (1) is a substitutional solid solution in which a portion of Mg and / or Ca is substituted with at least one selected from divalent Fe, Mn, and Co. It also includes a solid solution between Mg and Ca. While hydroxides of divalent M alone in solid solution are colored blue, brown, or pink, the solid solution oxygen absorber of formula (1) of the present invention has a strong white color when the amount of solid solution is small, and when the amount of solid solution exceeds 10 mol%, the white color decreases and the color changes to gray.

[0015] As the divalent easily oxidizable metal M which is the part that absorbs oxygen, Fe, Mn, and Co can be used. However, since Co is likely to be slightly pink-colored even after solid solution and is expensive, Fe and Mn are preferred. Since Fe has a smaller ionic radius than Mn, the solid solution range is wider than that of Mn, the thermal stability is higher than that of Mn, and it is cheaper than Mn, so it is most preferred.

[0016] The solid solution range x is 0 < x < 0.3, preferably 0.01 ≤ x ≤ 0.2, and particularly preferably 0.02 ≤ x ≤ 0.1. When the solid solution amount exceeds 0.2, the whiteness, oxidation resistance (storage stability), and heat resistance (thermal decomposition temperature) tend to decrease.

[0017] The oxygen absorber of formula (1) of the present invention further includes an OH-substituted solid solution in which a part of the OH groups is substituted with an organic acid and / or an organic ligand. In the case of partial substitution of the OH groups with an organic acid, there is an effect of making the crystal thickness thinner. In the case of partial substitution with an organic ligand, the crystal width can be made larger and the thickness can be made thinner (higher aspect ratio). The improvement of the aspect ratio has an effect of enhancing the gas barrier performance.

[0018] The organic acid for solid solution is monovalent or divalent, preferably monovalent. Preferred organic acids include carboxylic acids such as formic acid, acetic acid, propionic acid, benzoic acid, and sulfonic acids such as methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid.

[0019] Preferred organic ligands include monovalent oxycarboxylic acids such as glycolic acid and lactic acid, and amines such as ethylenediamine and triethanolamine.

[0020] The smaller the primary particles (crystallites, plate-like) of the oxygen absorber of the present invention, the faster the oxygen absorption rate, but the storage stability becomes worse, so an appropriate size is preferred. The width of the primary particles is 0.1 μm to 10 μm, preferably 0.2 μm to 10 μm, and particularly preferably 0.5 μm to 5 μm. The thinner the thickness of the primary particles, the better the transparency of the resin and the improvement of the gas barrier property, so it is preferably 0.2 μm or less, and particularly preferably 0.1 μm or less. The less the secondary particles aggregate, the better the transparency of the resin, which is preferable. Therefore, the average secondary particle size is in the range of 0.1 to 15 μm, preferably 0.2 to 10 μm, and particularly preferably 0.5 to 6 μm.

[0021] The oxygen absorber of the present invention is an inorganic crystal, and therefore does not itself allow gases such as oxygen to pass through. The larger the width of the primary particle, which is plate-like, and the higher the aspect ratio (10 or more, preferably 20 or more, particularly preferably 50 or more), the greater the gas barrier function (gas barrier properties) of the oxygen absorber of the present invention against permeation of gases including oxygen. Therefore, when the oxygen absorber of the present invention is kneaded into a resin and formed into a film, this resin film can have gas barrier properties not only against oxygen but also against all gases including HO. Therefore, the oxygen absorber of the present invention exhibits gas barrier properties superior to those of conventional oxygen absorbers due to the physical gas barrier properties resulting from the plate-like crystal shape and the chemical oxygen scavenging properties of the divalent Fe and Mn contained in the plate-like crystals.

[0022] Resins containing the oxygen absorbent of the present invention are transparent. Magnesium hydroxide solid solutions are particularly preferred because they have a refractive index closest to that of resins.

[0023] (Manufacturing method) The oxygen absorber of formula (1) of the present invention can be produced by a conventionally known method (see, for example, Japanese Patent Application Laid-Open No. 5-209084). (1) To a mixed aqueous solution of (A) a water-soluble Mg and / or Ca salt and (B) at least one water-soluble divalent salt selected from Fe, Mn, and Co, or to a mixed aqueous solution of A and B, (C) an organic acid and / or organic ligand is further added in an amount of less than 10 mol % per mole of the total of the divalent metals A and B, where the organic acid may be an alkali metal salt of an organic acid or an organic acid salt such as ammonium. (2) To the mixed aqueous solution (1) of (A) and (B) or (A), (B), and (C), an alkali is added to cause coprecipitation, followed by hydrothermal treatment, filtration, washing (water washing, etc.), drying, pulverization, classification, etc., as appropriate, to produce the absorber.

[0024] The amount of alkali added in the coprecipitation reaction is 0.5 equivalents or more, preferably 0.6 to 1.0 equivalents, and particularly preferably 0.7 to 0.9 equivalents, relative to the total equivalent of the divalent metal, and the temperature is 0 to 100° C., preferably 10 to 40° C., and particularly preferably 10 to 30° C. The hydrothermal treatment temperature is 100° C. or higher, preferably 120 to 250° C., and particularly preferably 150 to 200° C., and the time is 1 hour or more, preferably 2 to 10 hours, and particularly preferably 3 to 6 hours.

[0025] Specific examples of water-soluble divalent metal compounds include halides such as magnesium chloride, magnesium bromide, ferrous chloride, manganese chloride, and cobalt chloride; nitrates such as magnesium nitrate, ferrous nitrate, manganese nitrate, and cobalt nitrate; sulfates such as magnesium sulfate, ferrous sulfate, manganese sulfate, and cobalt sulfate; and organic acid salts such as magnesium acetate, magnesium propionate, ferrous acetate, manganese acetate, and cobalt acetate.

[0026] (1) Specific examples of alkali compounds include sodium hydroxide, potassium hydroxide ammonia water, calcium hydroxide, etc.

[0027] Specific examples of the organic acid and / or organic ligand compound used in (C) include monocarboxylic acids such as formic acid, acetic acid, and propionic acid, and sulfonic acids such as methanesulfonic acid and benzenesulfonic acid. Specific examples of the organic ligand compound include oxycarboxylic acids such as glycolic acid, lactic acid, and glyceric acid, amines such as ethylenediamine and triethanolamine, and polyhydric alcohols such as ethylene glycol and glycerin.

[0028] (Surface treatment) The oxygen absorber of formula (1) of the present invention can be given various functions by surface treatment. For example, to improve compatibility with resins and acid resistance, it is possible to use (a) higher fatty acids such as lauric acid and stearic acid, (b) alkali metal salts of the higher fatty acids, (c) anionic surfactants such as sodium dialkylsulfosuccinate, alkyl ether sulfate, 2-ethylhexyl alkyl sulfate ester sodium salt, sodium acylmethyl taurate, sodium alkylbenzenesulfonate, and oleoyl sarcosine, and (d) acid types / or alkali metal salts / or amino acids of mono- or diesters of orthophosphoric acid and stearyl alcohol. (e) silane-based coupling agents such as vinylethoxysilane and γ-aminopropyltrimethoxysilane; (f) titanate-based coupling agents such as isopropyltriisostearoyltitanate; (g) aluminum-based coupling agents such as acetoalkoxyaluminum diisopropylate; (h) fatty acid esters of polyhydric alcohols such as sorbitan monostearate; and (i) alkali metal salts of polycarboxylic acids and polysulfonic acids such as sodium polyacrylate and sodium polystyrene sulfonate.

[0029] To improve heat resistance, silica coating is performed by chemical adsorption of water glass followed by the addition of acid, silica coating by hydrolysis of methyl silicate, ethyl silicate, etc., silicone coating with silicone oil, etc. To enhance ultraviolet absorption and / or scattering, coating with fine particles of titanium oxide, zinc oxide, cerium oxide, etc. can be used.

[0030] The surface treatment is preferably carried out by a wet or dry method. The wet method is a method in which the oxygen absorber of the present invention is dispersed in a solvent such as water or alcohol, and a surface treatment agent is added to the dispersion while stirring. The dry method is a method in which a surface treatment agent is added to the powdered oxygen absorber of the present invention while stirring using a high-speed stirrer such as a Henschel mixer. The amount of surface treatment is appropriately selected and determined depending on the purpose, but the preferred range is generally 0.5 to 10 wt % based on the weight of the oxygen absorber of the present invention.

[0031] (Resin composition) The oxygen-absorbing resin composition of the present invention contains 0.1 to 300 parts by weight, preferably 1 to 200 parts by weight, and particularly preferably 5 to 150 parts by weight of the oxygen absorbent of the present invention per 100 parts by weight of resin. The optimal amount varies depending on the purpose. For example, if the purpose is oxygen absorption alone, it is 1 to 50 parts by weight, and if the purpose is gas barrier, it is 50 to 200 parts by weight.

[0032] (Processing method) There are no particular restrictions on the method of mixing and kneading with the resin, other than avoiding contact with the air as much as possible and taking care to prevent oxidation. Any method can be used as long as it allows the two to be mixed uniformly. For example, mixing and kneading can be done using a single-screw or twin-screw extruder, an open roll, a Banbury mixer, etc. There are also no particular restrictions on the molding method, and any known molding means can be used depending on the types of resin and rubber, the type of molded product, etc. Examples of molding means include extrusion molding, cast molding, inflation extrusion molding, blow molding, melt spinning, injection molding, injection blow molding, coextrusion blow molding, etc. Films, sheets, etc. can also be uniaxially or biaxially stretched.

[0033] Films and sheets formed from the resin composition of the present invention include single-layer films and multilayer films. These films can be used as various packaging materials. Generally, in the case of a single layer, the oxygen absorber of the present invention can be loaded into the resin at a high concentration to serve as a gas barrier layer. In the case of a multilayer film, the oxygen absorber of the present invention can be loaded into the resin at a relatively low concentration to serve as an oxygen absorbing layer. For example, a five-layer laminate film may be used, consisting of an adhesive (sealant) layer made of polyolefin (polypropylene, polyethylene, etc.) on the inside of the oxygen absorbing layer (for packaging food, etc.), a gas barrier layer made of EVOH (ethylene-vinyl alcohol copolymer), inorganic (silica, alumina, aluminum, etc.) vapor-deposited resin film, MXD6, aluminum foil, etc. on the outside, and an outermost outer layer made of PET, nylon, etc. The multilayer structure can have two or more layers, with no upper limit, and a paper layer can also be used.

[0034] (Type of resin) The resin used in the present invention means resin and / or rubber, and examples thereof include (A) thermoplastic resins such as polyethylene, copolymers of ethylene and other α-olefins, copolymers of ethylene and vinyl alcohol, vinyl acetate, ethyl acrylate or methyl acrylate, polybutene-1, poly-4-methylpentene-1, polystyrene, copolymers of styrene and acrylonitrile, copolymers of ethylene and propylene diene rubber or butadiene, polyvinyl acetate, polyvinyl alcohol, polyacrylate, polymethacrylate, polyurethane, polyester, polyether, polyamide, ABS, polycarbonate, polyvinyl chloride, chlorinated polyethylene, and chlorinated polypropylene; (B) thermosetting resins such as phenolic resin, melamine resin, epoxy resin, unsaturated polyester resin, and alkyd resin; and (C) rubbers such as EPDM, SBR, NBR, butyl rubber, chloroprene rubber, isoprene rubber, chlorosulfonated polyethylene rubber, silicone rubber, fluororubber, chlorinated butyl rubber, epichlorohydrin rubber, and chlorinated polyethylene rubber.

[0035] Preferred resins are thermoplastic resins such as polypropylene, polyethylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, polyamide, polystyrene and polyester.

[0036] The resin used in the adhesive layer preferably contains a carboxylic acid-modified polyolefin. The carboxylic acid-modified polyolefin is preferably a modified polyolefin polymer containing a carboxyl group formed by chemically bonding an ethylenically unsaturated carboxylic acid, its ester, or its anhydride to an olefin polymer. Linear low-density polyethylene and ethylene-vinyl acetate copolymer are particularly preferred olefin polymers.

[0037] In addition to the oxygen absorber, the resin composition of the present invention can contain other commonly used additives, such as antioxidants, ultraviolet absorbers, lubricants, crosslinking agents, light stabilizers, antistatic agents, pigments, and reinforcing agents such as magnesium hydroxide with a high aspect ratio, which can be appropriately selected and blended. The blending amounts of these additives are preferably in the range of 0.001 to 5 parts by weight per 100 parts by weight of the resin other than the reinforcing agents, and 5 to 200 parts by weight of the reinforcing agents.

[0038] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the examples, (A) primary particle size, (B) average secondary particle size, and (C) oxygen absorption amount were measured by the methods described below. (A) Primary particle size

[0039] The powder is sieved through a 60 mesh screen and dispersed in water with ultrasound for 5 minutes. The maximum width and thickness of five primary particles are measured using a scanning electron microscope (SEM), and the arithmetic mean value is used. (B) Average secondary particle diameter

[0040] A sample dispersed in the same manner as in (A) is measured with a laser diffraction particle size distribution analyzer (LA960 manufactured by Horiba), and the 50% cumulative secondary particle diameter is taken as the average secondary particle diameter. (C) Oxygen absorption amount (deoxygenation rate)

[0041] 880 mL of air (oxygen concentration 20.9%) and 3 g of oxygen absorber, or 3 g of oxygen absorber and 1 g of water, were placed in a glass bottle, which was then sealed with a lid equipped with an oxygen sensor. The change in the oxygen concentration in the air was measured at room temperature using a RIKEN KEIKI oxygen monitor. [Example]

[0042] All water used for dissolving metal salts was deionized water, which had been boiled to remove dissolved oxygen. 500 mL of a mixed aqueous solution of magnesium chloride and ferrous chloride (Fujifilm Wako Pure Chemical Industries, Ltd.) (Mg = 2.0 mol / L, Fe = 0.05 mol / L, 20 °C) and 1.8 g of a sodium lactate aqueous solution (Musashino Chemical Laboratory, concentration: 50 wt%) were placed in a 1 L four-neck flask. After replacing the atmosphere with nitrogen gas, 205 mL of a sodium hydroxide (Fujifilm Wako Pure Chemical Industries, Ltd.) aqueous solution (8 M / L, 20 °C) was added with stirring to cause coprecipitation.

[0043] The coprecipitate was transferred to a 1 L Hastelloy C autoclave, the atmosphere was replaced with nitrogen gas, and then hydrothermal treatment was performed at 200°C for 4 hours. After cooling to room temperature, it was filtered under reduced pressure in a nitrogen atmosphere and washed with water. The resulting cake was placed in a vacuum dryer and dried at 120°C for 2 hours. The dried product was white and was sieved through a 60-mesh sieve, after which XRD and compositional analysis were performed.

[0044] Although the XRD pattern is slightly shifted to the lower angle side, it shows the same diffraction pattern as magnesium hydroxide, indicating that this substance is a magnesium hydroxide solid solution. The sieved powder was dissolved in hydrochloric acid, and magnesium was separated and quantified by chelate titration, and divalent and trivalent iron by absorptiometry (Handbook of Analytical Chemistry, edited by the Chemical Society of Japan, Maruzen Publishing, p. 185). The chemical composition was as follows: Lactic acid was quantified by absorptiometry. Mg 0.94 Fe(2+) 0.06 (OH) 1.99 (C3H5O3) 0.01 (Trivalent iron was almost zero%) The primary particle width of this solid solution was 3.1 μm, the thickness was 21 nm, and the average secondary particle diameter was 2.6 μm. An oxygen absorption test was conducted using the sieved powder, and the oxygen concentration after 24 hours was 12.8% without added water and 5.0% with added water. This translates to oxygen absorption per gram of 23 cc / g and 47 cc / g, respectively. [Example]

[0045] The same procedure as in Example 1 was repeated, except that the ferrous chloride concentration was changed to 0.25 mol / L, the amount of sodium hydroxide was changed to 225 mL, sodium lactate was omitted, and the hydrothermal treatment temperature was changed to 150°C. The dried product was almost white, and its XRD showed the same tendency as in Example 1, indicating that it was a magnesium hydroxide-based solid solution. The chemical composition obtained by the method of Example 1 was as follows: Mg 0.88 Fe(2+) 0.12 (OH)2 (iron trivalent is 0.1% of total iron) The dried primary particles had a width of 1.2 μm, a thickness of 20 nm, and an average secondary particle diameter of 1.5 μm. An oxygen absorption test was conducted in the presence of water, and the oxygen concentration after 24 hours was 8.2%, which is equivalent to 37 cc / g per 1 g. [Example]

[0046] The same procedure as in Example 1 was repeated, except that ferrous chloride was replaced with cobalt chloride, sodium lactate was omitted, and the amount of sodium hydroxide was changed to 240 mL. The dried product was almost white, and XRD showed the same tendency as in Example 1, indicating that it was a magnesium hydroxide-based solid solution. The chemical composition obtained by the method in Example 1 was as follows: Mg 0.94 Co(2+) 0.06 (OH)2 The primary particle width of the dried material was 3.7 μm, the thickness was 90 nm, and the average secondary particle diameter was 3.9 μm. An oxygen absorption test was conducted in the presence of water, and the oxygen concentration after 24 hours was 11.8%, which is equivalent to 27 cc / g per 1 g. [Example]

[0047] The same procedure as in Example 1 was repeated, except that manganese nitrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was used instead of ferrous chloride. The dried product was almost white, and XRD showed the same tendency as in Example 1, indicating that it was a magnesium hydroxide-based solid solution. After dissolving the dried product in hydrochloric acid, the Mg and Mn contents were quantified by chelate titration, and the chemical composition was investigated, with the results shown below. Mg0.94 Mn 0.06 (OH)2 The primary particle width of the dried material was 2.5 μm, the thickness was 62 nm, and the average secondary particle diameter was 2.9 μm. When the dried material was subjected to an oxygen absorption test in the presence of water, the oxygen concentration after 24 hours was 11.2%. The oxygen absorption per 1 g was 45 cc / g. [Example]

[0048] 76 g of commercially available slaked lime was added to 600 mL of deionized water and dispersed using a stirrer. Then, 100 mL of an aqueous solution of ferrous chloride (1.0 mol / L) was added with stirring and the reaction was allowed to proceed. The resulting reaction slurry was filtered under reduced pressure, washed with water, and vacuum dried in the same manner as in Example 1. The dried product was slightly grayish-white, and although the XRD spectrum was slightly shifted to the high-angle side, it showed the same diffraction pattern as calcium hydroxide. Therefore, it is a solid solution of calcium hydroxide with the same Cd(OH)2 structure as magnesium hydroxide, in which some of the Ca has been replaced by divalent iron. Chemical analysis was performed using the same method as in Example 1 to determine the composition, and the results are as follows: Ca 0.9 Fe 0.1 (OH)2 (iron trivalent 0.2%) The primary particles of this solid solution had a width of 0.3 μm, a thickness of 120 nm, and an average secondary particle diameter of 1.2 μm. After sieving, the powder was subjected to an oxygen absorption test with the addition of water, and the oxygen concentration after 24 hours was 15.0%. Converted to an oxygen absorption amount per 1 g, it is 17 cc / g. [Comparative Example 1]

[0049] An oxygen absorption test was conducted using iron powder (Fujifilm Wako Pure Chemical Industries, Ltd.). The oxygen concentration after 24 hours was 17.1% for the powder alone and 11.9% for the powder with water added. The oxygen absorption per gram was 11cc / g and 26cc / g, respectively. Comparative Example 2

[0050] The same procedure was followed as in Example 1, except that the ferrous chloride concentration was changed to 0.6 mol / L and the hydrothermal treatment temperature was changed to 150°C. The dried product was light brown in color, and XRD showed the same magnesium hydroxide diffraction pattern as in Example 1, with the strongest peak at approximately 11°C, which is believed to be Mg-Fe(3+) hydrotalcite. Therefore, this dried product is a mixture of a magnesium hydroxide solid solution containing divalent iron and Mg-Fe(3+) hydrotalcites. An oxygen absorption test was performed on this dried powder with the addition of water, and the oxygen concentration after 24 hours was 16.4%. Therefore, the oxygen absorption per gram was 13 cc / g. (Oxygen absorber-containing resin) [Example]

[0051] The undried cake obtained by the method of Example 1 was placed in a 1 L four-neck flask together with approximately 500 mL of water, the air was replaced with nitrogen gas, and the mixture was dispersed using a stirrer and heated to approximately 80°C. 100 mL of an aqueous solution of 1.5 g of sodium stearate at approximately 80°C was added to the mixture while stirring, and the mixture was stirred for approximately 10 minutes to perform a surface treatment. The mixture was then filtered under a nitrogen stream, washed with water, and vacuum dried at 120°C for 1 hour.

[0052] The dried product was sieved through a 60 mesh sieve, and 8 g of the sieved product was mixed with 72 g of polypropylene (Prime Polymer, J707EG) and 0.15 g of an antioxidant (IRGANOX1010), and then melt-kneaded using a Brabender at 170°C for 10 minutes. The resulting melt was then kneaded using a press molding machine at a pressure of 50 kg / cm. 2 The resin was then pressure molded at 180°C for 5 minutes to produce a 1mm x 140mm x 160mm resin plate. This molded plate was then cut with scissors to approximately 5mm x 5mm x 1mm, and 30g of this (containing 3g of oxygen absorber) was used to conduct an oxygen absorption test. The oxygen concentration after 24 hours was 13.0% without the addition of moisture and 5.0% with the addition of moisture. The oxygen absorption per gram was 23mL / g and 47mL / g, respectively. [Example]

[0053] The change in oxygen absorption amount over time of the oxygen absorbent powder of the present invention (Example 1), the resin blended with the oxygen absorbent of the present invention (Example 6), and iron powder (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), a representative conventional oxygen absorber, was measured and the results are shown in Figure 1. From Figure 1, it can be seen that the oxygen absorbent of the present invention, even when blended with a resin, is superior to iron powder, a representative conventional oxygen absorber. [Example]

[0054] The surface-treated dry powder of the oxygen absorber of the present invention, prepared by the method described in Example 6, was mixed with linear low-density polyethylene (Prime Polymer, 1020L) for film at a weight ratio of 40:60. The mixture was melt-kneaded in a twin-screw extruder equipped with a feeder capable of purging with nitrogen gas, extruded into strands, and then cut into pelletizers to obtain oxygen-absorbing resin pellets. These pellets and LLDPE were molded into a three-layer film using a T-die method with an extruder (L / D = 28). The three-layer structure was LLDPE (12.5 μm thick), oxygen-absorbing resin layer (25 μm thick), and LLDPE (12.5 μm thick), with the oxygen-absorbing layer sandwiched between the LLDPE layers. The light transmittance of this film was measured using a spectrophotometer to find 98% at 700 nm and 81% at 450 nm, demonstrating high transparency.

[0055] To evaluate the gas barrier properties, the oxygen permeability was measured using the isobaric method. The result was 190 cc / m² / day, which is a significant reduction compared to the oxygen permeability of LLDPE (4750 cc / m² / day). The present invention may also be configured as follows. [Item 1] The following formula (1) (Mg and / or Ca) 1-x (M) x (OH) 2-nZ (A n- ) z (1) (However, in the formula, M represents at least one selected from divalent Fe, Mn, and Co, A represents at least one selected from organic acids and / or organic ligands with n valence [n is an integer in the range of 0 or 1 to 4], and x and z are in the following ranges respectively, 0 < x < 0.3, preferably 0.01 ≤ x ≤ 0.2, particularly preferably 0.02 ≤ x ≤ 0.1, 0 ≤ z < 0.1, preferably 0.001 ≤ z ≤ 0.05, particularly preferably 0.002 ≤ z ≤ 0.02) An oxygen absorber containing a magnesium hydroxide-based solid solution and / or a calcium hydroxide-based solid solution represented by the formula as an active ingredient. [Item 2] An oxygen absorber containing a magnesium hydroxide-based solid solution having Mg and / or Ca as Mg in formula (1) of Item 1 as an active ingredient. [Item 3] The oxygen absorber according to any one of Items 1 to 2, wherein M in formula (1) is divalent Fe. [Item 4] The oxygen absorber according to any one of Items 1 to 3, wherein A in formula (1) of Item 1 is at least one selected from lactic acid, glycolic acid, ethylenediamine, and triethanolamine. [Item 5] The oxygen absorber according to any one of Items 1 to 4, wherein the range of x in formula (1) of Item 1 is 0.01 ≤ x ≤ 0.2. [Item 6] The oxygen absorber according to any one of Items 1 to 5, wherein the lateral width of the primary particles is 0.5 μm or more. [Item 7] The oxygen absorber according to any one of Items 1 to 6, wherein the lateral width of the primary particles is 1 μm or more. [Item 8] The oxygen absorber according to any one of Items 1 to 7, which is surface-treated with at least one surface treatment agent selected from the group consisting of higher fatty acids, anionic surfactants, silane-based, titanium-based, and aluminum-based coupling agents, phosphate esters, esters of polyhydric alcohols and fatty acids, silicone oil, and water glass. [Item 9] An oxygen-absorbing and / or gas-barrier resin composition containing 0.01 to 300 parts by weight of the oxygen absorber according to any one of Items 1 to 8 per 100 parts by weight of the resin. [Item 10] A resin packaging body or a resin container containing the oxygen absorber according to any one of Items 1 to 9. [Item 11] Item 9. A method for producing an oxygen absorber according to any one of Items 1 to 8, characterized in that, under non-oxidizing atmospheric conditions that avoid contact with oxygen as much as possible throughout the entire production process, (1) a mixed aqueous solution (A+B) of (A) a water-soluble metal salt of Mg and / or Ca and (B) at least one water-soluble metal salt selected from divalent Fe, Mn, and Co, or (C) a mixed aqueous solution (A+B+C) to which an organic acid, (including an alkali metal salt and / or ammonium salt of an organic acid) and / or an organic ligand has been added in an amount of 10 mol % or less based on the total moles of the divalent metal, is added, (2) an alkali is added with stirring to cause a coprecipitation reaction, (3) the mixture is hydrothermally treated at 100°C or higher, and (4) the mixture is filtered, washed with water, and dried. [Section 12] Item 12. The method according to item 11, wherein the temperature and time of the hydrothermal treatment are 150°C to 250°C and 1 hour to 10 hours, respectively.

Claims

1. The following formula (1) (Mg and / or Ca) 1－ｘ (M) ｘ (OH) 2－ｎＺ (A ｎ－ ) ｚ (1) In the formula, M represents at least one selected from divalent Fe, Mn, and Co, A represents at least one n-valent organic acid and / or organic ligand (n is 0 or an integer of 1 to 4), and x and z are within the following ranges: 0<x≦0.2 and 0≦z<0.

1.

1. An oxygen absorber comprising, as an active ingredient, a magnesium hydroxide-based solid solution and / or a calcium hydroxide-based solid solution represented by the formula:

2. 2. The oxygen absorber according to claim 1, wherein the Mg and / or Ca is Mg.

3. 2. The oxygen absorber according to claim 1, wherein M is divalent Fe.

4. 2. The oxygen absorber according to claim 1, wherein A is at least one selected from the group consisting of lactic acid, glycolic acid, ethylenediamine, and triethanolamine.

5. 2. The oxygen absorber according to claim 1, wherein x is in the range of 0.01≦x≦0.

2.

6. 2. The oxygen absorber according to claim 1, wherein the width of the primary particles is 0.5 μm or more.

7. 2. The oxygen absorber according to claim 1, wherein the width of the primary particles is 1 μm or more.

8. 2. The oxygen absorber according to claim 1, which is surface-treated with at least one surface treatment agent selected from the group consisting of higher fatty acids, anionic surfactants, silane-based, titanium-based and aluminum-based coupling agents, phosphate esters, esters of polyhydric alcohols and fatty acids, silicone oil and water glass.

9. 9. An oxygen-absorbing and / or gas-barrier resin composition comprising 0.01 to 300 parts by weight of the oxygen absorbent according to any one of claims 1 to 8 per 100 parts by weight of resin.

10. A resin packaging material or a resin container containing the oxygen absorber according to any one of claims 1 to 8.

11. 9. A method for producing the oxygen absorber according to claim 1, wherein the method comprises the steps of: (1) preparing a mixed aqueous solution (A+B) of (A) a water-soluble metal salt of Mg and / or Ca and (B) at least one water-soluble metal salt selected from divalent Fe, Mn, and Co; or (C) preparing a mixed aqueous solution (A+B+C) to which 10 mol % or less of an organic acid or an alkali metal salt and / or ammonium salt of an organic acid, and / or an organic ligand has been added, based on the total moles of the divalent metals, under non-oxidizing atmospheric conditions in which contact with oxygen is avoided as much as possible throughout the entire production process; (2) adding an alkali to the mixed aqueous solution (A+B+C) with stirring to cause a coprecipitation reaction; (3) hydrothermal treatment at 100°C or higher; and (4) filtering, washing with water, and drying.

12. The method according to claim 11, wherein the temperature and time of the hydrothermal treatment are 150°C to 250°C and 1 hour to 10 hours, respectively.

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