WO2006095640A1 - Powdery oxygen absorbent material and process for producing the same - Google Patents

Abstract

A powdery oxygen absorbent material that has the properties of being responsive to metal detectors, being responsive to microwave ovens and moisture unwanted, and that exhibits an amount of oxygen absorbed and rate of oxygen absorption equal to or greater than those of iron based oxygen absorbent materials. There is provided a powdery oxygen absorbent material characterized by containing thermoplastic polymer (A) of 10 to 400 Mooney viscosity which in the measuring by differential scanning calorimeter (DSC) has no crystal melting peak or has a melting point of < 75°C, the thermoplastic polymer containing an allyl hydrogen and/or a hydrogen bonded with tertiary carbon in its molecule, and oxidation accelerating component (B), and characterized by having a specific surface area of ≥ 60 cm2/g.

Description

 Specification

 Powdered oxygen absorber and method for producing the same

 Technical field

 [0001] The present invention relates to a powdery oxygen absorbent material that can be suitably used for storage of metal products, foods, pharmaceuticals, photographic films, old documents, paintings, electronic products and the like.

 Background art

 [0002] These products were stored for the purpose of preventing deterioration of various products that are easily affected by oxygen, such as metal products, food, pharmaceuticals, photographic films, old documents, paintings, and electronic products. A deoxidizing material for removing oxygen in a packaging container or a packaging bag has been conventionally used.

 [0003] As a deoxidizing material, an iron-based oxygen absorbing material is mainly used, but an oxygen absorbing material mainly composed of catechol, ascorbic acid, and a resin that easily reacts with oxygen has also been proposed.

 [0004] The main reason why iron-based oxygen absorbers are used is that oxygen absorption per lg of iron-based oxygen absorber is 68cc, and the oxygen absorption rate is 18cc / (g'hr). This is the main factor.

 [0005] On the other hand, when iron-based oxygen absorbers are applied to packages such as foods, foreign objects cannot be detected by metal detectors, and there is a possibility of discharge and ignition by heating with a microwave oven, etc. The problem is also pointed out.

 [0006] To solve this problem, an oxygen absorbing material has been proposed which mainly contains a resin that easily reacts with catechol, ascorbic acid or oxygen. In particular, oxygen absorbers based on resins that easily react with oxygen do not require moisture for oxygen absorption reactions and can be used in low humidity environments.

[0007] Patent Document 1 discloses a powdery oxygen absorbent material (hereinafter referred to as Prior Art 1) composed of a liquid butadiene polymer, tall oil fatty acid, soybean oil fatty acid cobalt and zeolite, and Patent Document 2 includes a butadiene oligomer, Powdered oxygen absorbent material (hereinafter referred to as Conventional Technology 2) crosslinked by adding cobalt stearate and organic peroxide (di-2-t-butylperoxyisopropylbenzene). Patent Document 3 is obtained by emulsion polymerization. In addition, spherical particles of syndiotactic 1, 2 polybutadiene (hereinafter referred to as Conventional Technology 3) have been proposed. These oxygen absorbers The collecting material can absorb oxygen without the need for moisture. However, in the conventional technology 1, the conventional technology 2, and the conventional technology 3, the oxygen absorption performance of the iron-based oxygen absorber, that is, the amount of oxygen absorbed per gram of oxygen absorber is 68 cc, and the oxygen absorption rate is iron-based. Actually, only inferior to 18cc / (g * hr) of oxygen absorbing material is obtained.

[0008] Patent Document 1: Japanese Patent Laid-Open No. 29741

 Patent Document 2: Japanese Patent Laid-Open No. 11-70331

 Patent Document 3: JP-A-9-291120

 Disclosure of the invention

 Problems to be solved by the invention

[0009] The present invention is a powder that can be applied to a metal detector, can be applied to a microwave oven, has no characteristics of moisture, and has an oxygen absorption rate and an oxygen absorption amount higher than those of iron-based oxygen absorbers. It aims at providing a gaseous oxygen absorber.

 Means for solving the problem

 [0010] As a result of intensive studies to solve the above problems, the present inventors have found that Mooney viscosity is

 10 to 400 and has no crystalline melting peak as measured with a differential scanning calorimeter (DSC) or has a melting point of less than 75 ° C., i.e. substantially non-crosslinked, substantially amorphous By using a thermoplastic resin having hydrogen in its molecule and hydrogen bonded to tertiary carbon in the molecule, it is possible to achieve iron that cannot be achieved by the prior art by applying appropriate additive formulations and appropriate shapes. The present inventors have found that a powdery oxygen absorber having an oxygen absorption rate and an oxygen absorption amount equal to or higher than those of the system oxygen absorber can be obtained, and the present invention has been made.

 [0011] That is, the present invention is as follows.

(1) Allyl hydrogen and Z or Class 3 having Mooney viscosity of 10 to 400 and no crystal melting peak or melting point of less than 75 ° C as measured by differential scanning calorimetry (DSC) A powdery oxygen absorbent comprising a thermoplastic polymer (A) having hydrogen bonded to carbon in a molecule and an oxidation promoting component (B), and having a specific surface area force of S60 cm ² Zg or more.

 (2) The powdery oxygen absorbent as described in (1) above, wherein the thermoplastic polymer (A) has a viscosity of 20 to 150.

(3) Polymer or copolymer in which thermoplastic polymer (A) contains 50% by weight or more of butadiene units The powdery oxygen absorbent according to (1) or (2) above, which is a body.

 (4) The thermoplastic polymer (A) is a block or random structure copolymer comprising 50 to 99% by weight of butadiene units and 1 to 50% by weight of styrene units. ) To (3), the powdery oxygen absorbent according to any one of the above.

 (5) The thermoplastic polymer (A) contains 50 to:! OOOppm of antioxidant (C), characterized in that the above (1) to (4) Powdered oxygen absorber.

 (6) The thermoplastic polymer (A), the oxidation promoting component (B), and the thermoplastic polymer (A) contain fine particles (D) that have adhesion but are difficult to adhere to each other. (1) to (5) above, wherein the particle diameter is 10 xm to 5 mm, and at least a part of the fine particles (D) is located on the surface of the powder (A) and (B) The powdery oxygen absorber according to any one of the above.

 (7) A method for producing a powdery oxygen absorbent comprising the following steps.

Step (X): Allyl hydrogen having a viscosity of 10 to 400 and having no crystal melting peak as measured with a differential scanning calorimeter (DSC) or having a melting point of less than 75 ° C. and / or Alternatively, a process of melting and mixing the thermoplastic polymer (A) having hydrogen bonded to tertiary carbon in the molecule and the oxidation promoting component (B) in a heated and molten state.

Process (Y): Process of pulverizing the molten mixture obtained in process (X)

Step (Z): A step of exposing the molten mixture obtained in step (X) or the pulverized material obtained in step (Y) to radiation of 2 kyrogray or more.

Step (S): A step of storing the molten mixture or powdered product in a low oxygen atmosphere.

The invention's effect

 The powdered oxygen absorbent material of the present invention can be used in a low humidity environment, which is a characteristic of a resin-based oxygen absorbent material, can detect foreign matter with a metal detector, and can be used without any problems even when placed in a microwave oven. It has the effect of having both characteristics such as points and oxygen absorption and oxygen absorption rate superior to those of iron-based oxygen absorbers. Furthermore, unlike conventional iron-based and organic oxygen-absorbing materials, it has an effect of absorbing oxygen even in a carbon dioxide atmosphere, and is particularly preferable because it can be applied to gas replacement packaging using carbon dioxide.

Brief Description of Drawings FIG. 1 is a diagram showing oxygen absorption curves of Example 1 and Comparative Examples 1 to 4.

 FIG. 2 is a graph showing the relationship between the amount of antioxidant (C) added in Example 3 and the induction period of the powdered oxygen absorber.

 Explanation of symbols

 [0014] 1 Oxygen absorption curve of powdery oxygen absorber of Example 1

 2 Oxygen absorption curve of powdered oxygen absorber of Comparative Example 1

 3 Oxygen absorption curve of powdered oxygen absorber of Comparative Example 2

 4 Oxygen absorption curve of powdered oxygen absorber of Comparative Example 3

 5 Oxygen absorption curve of iron-based oxygen absorber of Comparative Example 4

 ♦ When using a phenolic antioxidant as the antioxidant in Example 3

 □ In the case of using Zio antioxidant as the antioxidant of Example 3

 BEST MODE FOR CARRYING OUT THE INVENTION

[0015] The present invention will be specifically described below.

 First, it will be shown using FIG. 1 that the present invention is superior in oxygen absorption performance compared to the prior arts 1 to 3.

 [0017] FIG. 1 shows the oxygen absorption amount obtained from the oxygen concentration for each elapsed time in a container containing each powdery oxygen absorbent according to the oxygen absorption measurement method described later. It is the figure taken on the axis. Curve 1 in FIG. 1 is the oxygen absorption curve of the powdered oxygen absorber of the present invention (Example 1), curve 2 is the oxygen absorption curve of the powdered oxygen absorber of the prior art 1 (Comparative Example 1), and curve 3 is Oxygen absorption curve of powdered oxygen absorber of Conventional Technology 2 (Comparative Example 2), Curve 4 is the oxygen absorption curve of powdered oxygen absorber of Conventional Technology 3 (Comparative Example 3), Curve 5 is a commercially available iron-based oxygen absorber The oxygen absorption curve of the material (Comparative Example 4) is shown.

[0018] Here, when the oxygen concentration reaches saturation, the oxygen absorption amount per lg of powdered oxygen absorbent is defined as “saturated oxygen absorption amount” (unit: cc / g), and the maximum slope of the oxygen absorption curve Was defined as “maximum oxygen absorption rate” (unit: cc / (g′hr)). If the saturated oxygen absorption amount is large, the amount of oxygen absorbing material to be used can be reduced, so that the product can be made inconspicuous and the cost can be reduced. If the maximum oxygen absorption rate is large and / or the time until the oxygen absorption rate is maximum is short, This is especially preferred when used for fast-scratched foods such as doll-yaki, side dishes and lunch boxes. In general, sachet-type oxygen absorbers sold in the market generally take less than 4 hours to reach the maximum oxygen absorption rate. Is set to

In FIG. 1, in the powdery oxygen absorbent material of the present invention shown as curve 1, oxygen absorption starts immediately after the start of measurement, 18 cc / g oxygen is absorbed 0.5 hours later, and 0.5 hours later In a relatively short time, the oxygen absorption rate reached its maximum, and the maximum oxygen absorption rate was 38 cc / (g'hr). After 0.5 hours, the oxygen absorption rate gradually decreased, but the oxygen absorption reached 190 ccZg after 24 hours, almost saturated after about 48 hours, and the saturated oxygen absorption reached 230 ccZg. .

[0020] On the other hand, in the commercially available iron-based oxygen absorber shown as curve 5, the oxygen absorption rate reaches its maximum after 0.5 hours and reaches 18 cc / (g'hr), and the oxygen absorption reaches almost saturation after about 24 hours. At that time, the amount of saturated oxygen absorbed was 68 ccZg.

[0021] Therefore, it can be seen that the powdered oxygen absorbing material of the present invention is very excellent in oxygen absorbing characteristics as compared with commercially available iron-based oxygen absorbing materials.

[0022] On the other hand, in the prior art 1 shown as curve 2, the oxygen absorption amount is 2 cc / g even after 4 hours, and the maximum oxygen absorption rate is lc after 16 hours from the start of measurement. c / (g'hr). Also, the oxygen absorption reached saturation after 3 days, and the saturated oxygen absorption at that time was 41 cc / g.

[0023] Next, in the prior art 2 shown as curve 3, the maximum oxygen absorption rate at which the initial oxygen absorption amount until 8 hours after the start of measurement is lower than that of commercially available iron-based oxygen absorbers is 14 cc / (g'hr) It was. In addition, the oxygen absorption reached saturation after 3 days, and the saturated oxygen absorption at that time was 13

It was 2cc / g.

 [0024] Furthermore, in the prior art 3 shown as curve 4, the oxygen absorption performance was hardly exhibited after 24 hours, and the maximum oxygen absorption rate was approximately OccZ (g'hr). The oxygen absorption reached almost saturation after 30 days, and the saturated oxygen absorption at that time was 18 cc / g.

[0025] As described above, it can be seen that the present invention has a marked effect compared to the prior art.

[0026] Furthermore, unlike the conventional iron-based oxygen absorbers and organic oxygen absorbers, the powdered oxygen absorber of the present invention absorbs oxygen even in an atmosphere containing carbon dioxide. Carbon dioxide is bacteriostatic In order to have an effect, it is often used for gas replacement packaging, which is one of CA packaging (Controlled Atmosphere Packaging) or MA packaging (Modified Atomosphere Packaging) for maintaining freshness. Therefore, the powdery oxygen absorbent material of the present invention has the advantage that it can be applied to gas replacement packaging in which conventional oxygen absorbent materials cannot be used.

 [0027] The components constituting the powdery oxygen absorbing material of the present invention will be described below.

 (1 1 1) Thermoplastic resin (A)

 Thermoplastic resin (A) having hydrogen in the molecule and hydrogen bonded to Z or tertiary carbon are polybutadiene, polyisoprene, butadiene / isoprene copolymer, styrene / butadiene copolymer, styrene Z isoprene. Copolymer, butadiene / isoprene / styrene copolymer, copolymer of ethylene and cyclic alkylene, resin containing cyclohexene group, polypropylene, ethylene Z propylene copolymer, MXD6 polyamide (metaxylene / nylon adipate) ) And the like are exemplified as a resin mainly composed of at least one selected from the group consisting of. Those having 1,2-bonds and 1,4 bonds, such as polybutadiene and polyisoprene, may be single or mixed. In addition, those having Cis- and Trans structures may be single or mixed.

 [0028] Among these, a polymer containing 50% by weight or more of butadiene units preferred by polybutadiene, polyisoprene, and styrene / butadiene copolymer from the viewpoint of high oxygen absorption and oxygen absorption rate, or A copolymer is more preferred.

Of these, from the viewpoint of a high oxygen absorption rate, a block or random structure copolymer comprising 50 to 99% by weight of butadiene units and 1 to 50% by weight of styrene units is preferable 60 to copolymers of block structure consisting of 80 weight _^0/0 of butadiene units and 20 to 40 weight _^0/0 of styrene unit are more preferred. The reason for this is not clear, but it is thought that the oxygen absorption rate is improved because the styrene unit part becomes the oxygen permeation path and oxygen diffusion is improved. In addition, the inclusion of a styrene unit as the copolymer component is also preferable from the viewpoint of making the mixture of the thermoplastic polymer (A) and the oxidation promoting component (B) brittle and making the pulverization process easy.

[0030] In addition, those having different stereoregularities such as isotactic, syndiotactic and atactic may each be single or mixed. Among these, from the viewpoint of oxygen absorption performance, Those with atactic structure are preferred.

 [0031] In addition, a copolymer of ethylene and a cyclic alkylene and a resin containing a cyclohexene group are also preferable, and an ethylene / vinylcyclohexene copolymer, an ethylene / cyclopentene copolymer, and an ethylene / cyclopentene / 4 are particularly preferable. —Buylcyclohexene copolymer, ethylene / methyl acrylate, Z cyclohexenyl methyl acrylate copolymer, cyclohexenyl methyl acrylate / ethylene copolymer, cyclohexenyl methyl methacrylate Z styrene copolymer And cyclohexenylmethyl attalate homopolymer or methyl acrylate z-cyclohexenyl methyl acrylate copolymer.

 [0032] The thermoplastic resin (A) is a random copolymer or a block copolymer with another monomer, which may be a homopolymer, for the purpose of improving characteristics and the like. It may be a blend with other polymers.

 [0033] The thermoplastic resin (A) of the present invention has a Mooney viscosity of 10 to 400 for exhibiting excellent oxygen absorption performance. Within this range, the shape of the powdery oxygen absorber can be maintained without supporting the thermoplastic resin (A) on the carrier, and excellent oxygen absorption performance can be exhibited. In addition, the handleability of the powdery oxygen absorber is improved. Furthermore, since it is difficult for the particles to be fused, it is possible to develop excellent high-temperature storage suitability. The Mooney viscosity is preferably 20 to 300, more preferably 20 to 150.

 [0034] Mooney viscosity is affected by various factors such as the molecular weight, molecular weight distribution, branched structure, entanglement, and point density of the polymer. Since these various factors affect the Mooney viscosity in a complicated manner, it is difficult to determine them uniquely from only the Mooney viscosity value.

 [0035] Further, by adding a peroxide to the thermoplastic resin (A), heating the thermoplastic resin (A), and further irradiating the thermoplastic resin (A) with an electron beam, radiation, or the like. The one that is bridged over has a Mooney viscosity of over 400. Here, “substantially crosslinked” refers to a state in which a thermoplastic resin subjected to crosslinking treatment does not dissolve even when immersed in toluene at 25 ° C. for 24 hours. The powdery oxygen absorber of the present invention dissolves easily when immersed in toluene.

[0036] In the present invention, the viscosity of the resin layer 121 means that the thermoplastic resin (A) constituting the powdered oxygen absorbing material of the present invention is dissolved in powdered oxygen by a reprecipitation method as described later. Separated from the material, JIS K6 According to 300, preheating time is 1 minute, rotor rotation time is 4 minutes, and measured with Mooney viscometer under test temperature of 100 ° C.

 [0037] Here, the viscosity of the thermoplastic resin (A) has almost no effect even if it contains an oxidation promoting component (B) described later in an amount within the range of the present invention. Even if the oxidation promoting component (B) remains, it can be measured in the state where it is.

[0038] If there is a concern that the oxygen absorber absorbs oxygen before the measurement and the Mooney viscosity changes, a Fourier transform near-infrared spectrophotometer (hereinafter referred to as FT) is used. The peak of the carboxyl group generated by the oxygen absorption reaction (abbreviated as _IR) (for example, l YlOcnT ¹ peak) was divided by the 1, 4 trans group peak (967 cm- ¹ ) of the thermoplastic resin (A). It is necessary to obtain the oxygen absorption value from the following formula 1 based on the value, and to correct the Mooney viscosity before absorbing oxygen based on this value. If the peak of the 1,4 trans group is unclear, use the peak of the 1,4 cis group or the bull group.

(Equation 1) Oxygen absorption amount value (cc / g) = {FT -IR peak height of 1710 cm ^{_ 1} was measured (cm) / FT-967 cm ^{_ 1} peak height measured by IR (cm)} X Factor H

 The coefficient H is a value determined by experiment, and is 504, for example, when the thermoplastic resin (A) is polybutadiene.

 [0039] The thermoplastic resin (A) of the present invention has a crystal melting peak or a crystal melting peak when measured with a differential scanning calorimeter (DSC) for exhibiting excellent oxygen absorption performance. In this case, the melting point is less than 75 ° C.

 [0040] A crystal melting peak having a melting point of 75 ° C or higher is not preferable because the molecular motion of the resin is limited and the oxygen absorption performance deteriorates. For the same reason, the melting point is preferably less than 5 ° C, more preferably less than 50 ° C, and even more preferably no crystal melting peak.

[0041] In addition, the thermoplastic resin (A) of the present invention preferably has a crystal melting energy of less than lOOmjZmg from the viewpoint of preventing the molecular motion of the resin from being restricted and deteriorating the oxygen absorption performance. . For the same reason, the crystal melting energy is preferably less than 50 mj / mg, more preferably the crystal melting energy is 20 mjZmg, and even more preferably no crystal melting peak. [0042] The crystal melting peak (melting point) and crystal melting energy in the present invention are obtained from a DSC curve measured by differential scanning calorimetry, and this measuring method is as follows.

 [0043] The thermoplastic resin (A) constituting the powdery oxygen absorbing material of the present invention is separated from the powdered oxygen absorbing material by a dissolution reprecipitation method, and a sample of about 10 mg from _50 ° C to 200 ° C according to JIS K7121. Increase the temperature at a rate of 10 ° C / min between ° C and hold for 5 minutes, then decrease the temperature from 200 ° C to _50 ° C at a rate of 10 ° C / min, hold for 5 minutes and then further _ The melting point is the crystal melting peak temperature of the DSC curve obtained at the second temperature increase from 50 ° C to 200 ° C at a rate of 10 ° CZ. In addition, according to JIS K7122, the energy per unit weight of the area enclosed by a straight baseline drawn from the melting start temperature to the melting end temperature in this DSC curve was defined as the crystal melting energy.

 [0044] Here, the DSC measurement of the thermoplastic resin (A) has almost no effect even if it contains an oxidation promoting component (B) to be described later in an amount within the range of the present invention. The measurement may be performed with the oxidation promoting component (B) remaining.

 (1 2) Oxidation promoting component (B)

 The oxidation promoting component (B) has a catalytic action for promoting the oxidation of the thermoplastic resin (A) in the presence of oxygen. As the oxidation accelerating component (B), an oxidation catalyst such as a transition metal catalyst, a zinc compound or an aluminum compound is preferably used, as is known in the auto-oxidation of ordinary organic compounds. Also included are initiators such as photoinitiators and thermal initiators, and exothermic agents.

[0045] Here, the transition metal catalyst is a metal salt selected from the first, second or third transition series of the periodic table, which can be easily interconverted between at least two oxidation states. Preferable specifically, manganese (II) or (111), iron (II) or (111), cobalt (II) or (III), nickel (II) or (III), copper (I) or (II) Rhodium (II), (III) or (IV), silver (I) or (II), and norenium (II) or (III). The oxidation state of the metal at the time of introduction is not limited to the active form. Suitable counterions for this metal include salt ions, acetate ions, stearate ions, palmitate ions, 2-ethylhexanoate ions, neodecanoate ions, oleate ions, linoleate ions, Linolenic acid ion, ota Examples thereof include tyrate ion or naphthenate ion. Examples of these salts include cobalt 2-ethylhexanoate (II), cobalt oleate (II), cobalt neodecanoate (II), cobalt naphthenate, copper naphthenate, and iron naphthenate. it can. Further, silver oxide, titanium oxide, zinc oxide, zinc naphthenate, antibacterial agents containing silver ions, and the like are also preferable examples.

 [0046] Further, when the oxidation promoting component (B) is a metal fatty acid salt or the like, the component containing a carbon-carbon unsaturated bond in the fatty acid portion is the oxidation promoting component (B) in the powdery oxygen absorbent. Is incorporated into the resin structure, and the powdered oxygen absorbent component force catalyst is less likely to leak, which is preferable.

 [0047] Examples of oxidation catalysts for aluminum compounds include alkylaluminum such as triethylaluminum, triisobutylaluminum, jetylaluminum chloride, ethylaluminum sesquichloride, ethylaluminum dichloride, and tri-n_octylaluminum. Examples can be exemplified.

 [0048] Examples of the photoinitiator include a radical photopolymerization initiator, a cationic photopolymerization initiator, an anion photopolymerization initiator, and the like, and benzophenone, anthraquinone, naphthoquinone, and benzoquinone are preferred. It is done.

 [0049] The content of the oxidation promoting component (B) is preferably 0.0001 wt% or more and 5 wt% or less in the thermoplastic resin (A). Preferably it is 0.001 to 3 weight%. In the case of a transition metal catalyst, based on the metal content (excluding ligands, counterions, etc.), preferably in the thermoplastic resin (A), preferably from 0.0001% to 5% by weight More preferably, it is in the range of 0.001 wt% to 2 wt%, more preferably 0.01 wt% to 1.5 wt%.

 [0050] However, since the powdery oxygen absorber of the present invention increases the reactivity with oxygen by increasing the specific surface area, the larger the specific surface area, the less the oxidation promoting component (B) may be. In some cases, only a small amount of the polymerization catalyst remaining in the resin (A) can be an effective oxidation catalyst.

 (1 1 3) Other ingredients

The powdery oxygen absorber of the present invention may include various components exemplified below. (1 3-1) Antioxidant (C) Antioxidants (c) are all substances that block the oxidative degradation or crosslinking of polymers, such as phenolic antioxidants, phosphoric antioxidants, phenolic antioxidants, hindered amine antioxidants, and An example is a rataton antioxidant.

 [0051] In the powdery oxygen absorbing material of the present invention, it is preferable that the antioxidant (C) is contained in the thermoplastic polymer (A) in an amount of 50 ppm to 1000 ppm.

 [0052] If the amount of the antioxidant (C) is too large, the oxygen absorption reaction of the powdery oxygen absorbent is hindered, and the induction period becomes very long. On the other hand, if the abundance is too small, the thermoplastic polymer is oxidized during the molding calorie such as the melt mixing step in the production method of the preferred powdery oxygen absorbent material of the present invention described later, and the oxygen as the powdery oxygen absorbent material. Absorption performance is reduced, or the induction period is too short, so that it is exposed to oxygen when used by the user. Oxygen absorption characteristics are consumed. For these reasons, the amount of added calories in the antioxidant IJ (C) is preferably 50 ppm to 1000 ppm force S, more preferably 100 ppm to 800 ppm force S.

 Here, the induction period refers to the time from when the powdered oxygen absorber is exposed to oxygen until the start of useful oxygen absorption. In other words, it is the period from when the user wants an oxygen absorption effect and starts using the powdered oxygen absorber until it begins to develop useful oxygen absorption performance, and is the waiting period until the effect is achieved by the user. is there. This induction period is preferably a few hours to a few days, depending on the application. In particular, when it is used for fast-scratched foods such as buns, fruit cakes, doll baked foods, side dishes and lunch boxes, this induction period should be shorter than 6 hours as an example. Also, if the induction period is too short, the oxygen is absorbed during the period from when the user exposes the powdered oxygen absorber to oxygen until it is packaged with various items that are susceptible to alteration by oxygen (user working time). As an example in which absorption characteristics are consumed, a length of a certain length or more is preferable, 30 minutes or more is preferable.

[0054] In controlling the induction period, the antioxidant (C) is preferably one having a radical scavenging effect, more preferably one having a peroxy radical scavenging effect. These include phenolic antioxidants and hindered amine antioxidants. [0055] Examples of phenolic antioxidants include 2,6bis (2'-hydroxy-3'-t-butyl-5-methylbenzyl) -4 methylphenol, 4,4-methylene bis (6-t-butyl-2- Methyl phenol), 4,4-methylene bis (2, 6-di-tert-butylenophenol), 2,6-di-t_butyl _4_methyl phenol, 4, mono-bis-bis (6_t_butyl _3_methyl phenol), 4, 1-Butylidenebis (6_t_Butyl_3_Methylphenol), 2, 2 '—Methylenebis (4-methyl-6_t_Butylphenol), 2, 2'—Methylenebis (4-ethyl) _6_t _Butylphenol), 2, 6 —Di _t_Butyl _4_Ethylphenol, 1, 1,3-Tris (2-methyl _4—Hydroxy _5_t_Butylphenyl) butane, n-octadecyl 1_ (4-Hydroxy _3,5 -Di_t_butylphenyl) pro Onate, tetrakis [methylene mono 3_ (3,5-di-t_butyl _4-hydroxyphenyl) propionate] methane, 2,5-di-t-amylhydroquinone, 2,5-di-di-t-butylhydroquinone, hydroquinone, p-methoxyphenol, 2_t butylhydroquinone, n-octadecyl-3-(-hydroxy-3,5--di-t-butylphenol) propionate, triethyleneglycol bis [3- (3-t-butylphenol 5-methyl-4-hydroxyphenyl) Propionate], 1, 6-hexanediol —bis [3— (3, (3,5 di-tert-butyl 4-hydroxyphenyl) propionate], 2,4 bis- (n-octylthio) -6- (4-hydroxy 3,5 —Di-tert-butylanilino) —1, 3, 5-triazine, pentaerythrityl tetrakis [3— (3, 5-didibutynole 4-hydroxypheninole Propionate], 2, 2 thiodiethylenebis [3— (3,5—di-tert-butyl 4-hydroxyphenyl) propionate], octadecyl-3— (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, N, N '—hexamethylenbis (3,5-di-t_butyl_4-hydroxymonohydrocinnamamide), 3,5_di-t-butyl _4-hydroxy monobenzylphosphonate monojetyl ester, 1 , 3, 5 — Trimethylolene 2, 4, 6_tris (3, 5_dibutyl _4-hydroxybenzyl) benzene, 2, 4_bis [(octylthio) methyl] _o_cresol, other tocopherols, etc. And tocol derivatives.

[0056] Examples of phosphorus antioxidants include triphenyl phosphite, tris (2-ethylhexyleno) phosphite, tridecino phosphite, tris (tridecino) phosphite, tetra (trideci Nore) 4, A '—isopropylidene didiphenol diphosphite, trilauryl monotrithiophosphite, tris (2,4 di-t-butylphenyl) phosphite, tris (nonilated-phenenole) phosphite, distearyl pentaerythritol Examples include diphosphite, 2,2-methylenebis (4,6-di_t_butylphenyl) octyl phosphite, and bis (2,6-di_t_butyl monomethylphenyl) pentaerythritol monodiphosphite.

 [0057] Examples of thio antioxidants include tetrakis [methylene _ 3 _ (dodecylthio) propionate] methane, Ni _ dibutyl 1 dithio 1 force rubamate, Zn_dibutyl 1 dithio 1 force rubamate, Cd_ethyl 1 phenyl 1 dithiol rubamate, thiourea, 2_menolecapto-benzimidazole, dilauryl thiodipropionate, distearyl thiodipropionate pionate.

 [0058] Examples of hindered amine antioxidants include dimethyl succinate _ 1 _ (2-hydroxyethynole) _ 4-hydroxy-1,2,2,6,6-tetramethylpiperidine polycondensate, poly [{(6 1, 3,3 tetramethylbutyl) amino 1,3,5 triazine 1,2,4-diyl)} {((2,2,6,6 tetramethyl-1-piperidyl) imino} hexamethylene {(2, 2, 6,6 tetramethyl-1-4-piperidyl) imino}], N, N'-bis (3-aminopropyl) ethylenediamine-1,2,4-bis [N butynole N- (1, 2, 2, 6, 6-pentamethyl 1-piperidyl) amino] 6-chloro-1,3,5-triazine condensate.

 [0059] Examples of the rataton antioxidant include a reaction product of 3hydroxy-5,7-di-butyl-furan-2-one and o-xylene.

 [0060] When two or more types of antioxidants are used in combination, phenolic antioxidants are added at 50 ppm to 1000 ppm, and other types of antioxidants are added at 50 ppm or more to ensure stable processing. This is preferable because it is easy to achieve both high performance and high oxygen absorption performance.

 (1— 3— 2) Fine particles (D)

 The fine particles (D) give and maintain an appropriate shape to the main agent composed of the thermoplastic resin (A) and the oxidation promoting component (B), and are at least as described above under the conditions at the time of production and storage of the powdery oxygen absorbent. The main agent has a function of making it difficult to adhere to each other.

[0061] At least a partial force of the fine particles (D) is integrated with the main agent so as to be positioned on at least a part of the surface of the main agent. This prevents the adhesion of the main ingredients Become. Preferably, the fine particles (D) are positioned over the entire surface of the main agent.

 The fine particles (D) preferably have an average primary particle size of 0.01 μm to 1 mm, more preferably 0.05 μm to 500 μm, and still more preferably 0.1 μm. m to 100 μm. Within such a range, irregularities occur on the surface of the powdery oxygen absorber, and adhesion between the powdery oxygen absorbers is prevented and as a result, a large surface area is secured.

 [0063] For the same reason, the value S1 .:! To 500,000 obtained by dividing the average particle size of the main agent by the primary particle size of the fine particles (D) is preferably S, more preferably 2 to: 10000, more preferably 5 to 1000. Within this range, the fine particles (D) form irregularities on the surface of the oxygen absorber (A), and adhesion between the powdery oxygen absorber particles is less likely to occur.

 [0064] As such fine particles (D), inorganic particles (D1) or organic particles (D2) may be used as long as they are ordinary solid particles that do not easily adhere to each other in a high temperature environment (for example, 40 ° C). But it ’s okay. Whether or not it is difficult to adhere to each other is determined by placing the primary particles of the fine particles (D) in a container and leaving them at 40 ° C for 1 day, and then observing them with secondary microscopes by observation with an optical microscope or electron microscope. It can be judged by whether or not aggregation occurs.

 [0065] As used herein, adhesion means that two different types of substances adhere to each other by forces such as mechanical interaction, physical interaction, chemical interaction, and electrostatic interaction. Yeah.

 [0066] The content of the fine particles (D) in the powdery oxygen absorbent is such that the content of the fine particles (D) is small in view of increasing the stoichiometric oxygen absorption per unit weight of the oxygen absorbent. Although it is preferable, when the content of the fine particles (D) is small, the adhesion preventing effect between the powdery oxygen absorbent particles tends to be small. The content range of the fine particles (D) is 10 to 1000 parts by weight, preferably 30 to 450 parts by weight, with respect to 100 parts by weight of the thermoplastic resin (A) in the powdery oxygen absorbent. Part. Examples of the inorganic particles (D1) include particles of metals, metal compounds, and other inorganic substances.

 [0067] Examples of the metal particles include iron powder, aluminum powder, gold powder, copper powder, magnesium powder, and magnesium powder (alloy powder of aluminum and magnesium), preferably iron powder and aluminum powder. It is.

[0068] Examples of the metal compound particles include oxide, hydroxide, aluminate, aluminosilicate, sulfate, phosphate, and the like. Preferably, aluminum compound particles More preferred are aluminum oxide and hydroxide particles. Aluminum oxide and hydroxide particles include α-alumina, γ-alumina, r-aminoremina, δ-alumina, χ-alumina, ρ-alumina, anhydrous aluminum compounds such as activated alumina, and Al (OH) or AlO. -Gibbsite, bayerite, norstranda represented by 3H O

 3 2 3 2

 It is represented by trihydrate of aluminum compounds such as Ito and Α10 (ΟΗ) or Al〇 · · 〇

 2 3 2

 Monohydrate of aluminum compounds such as rube-mite and diaspore, and todite (

And particles such as 5A1 Η · Η〇) and anoreminagenore (A1〇 ηΗ Ο). More preferred

2 3 2 2 3 2

 Examples thereof include boehmite and activated alumina particles. Other preferred examples include particles such as zeolite.

 [0069] As particles of other inorganic substances, silica gel, activated clay, activated carbon, pearlite, sand, rock, metamorphic rock, igneous rock, sedimentary rock, granite, carbide, chromium oxide, diamond, nitrided nitride, zirconia, boron nitride , Etc., and preferably particles such as activated carbon and pearlite.

 [0070] Examples of the organic particles (D2) include resin powder, food powder, and other organic particles.

[0071] The resin powder may be thermoplastic resin particles or thermosetting resin particles. For example, polyethylene, polytetrafluoroethylene, polypropylene, polyvinyl chloride, polystyrene, polyvinyl alcohol, polyacrylonitrile, poly 1 Butene, poly (vinyl acetate), poly (vinyl fluoride), poly (4-methylpentene) 1, poly (vinylidene chloride), poly (vinylidene fluoride), poly (methyl methacrylate), poly (chlorotrichloroethylene), polybutadiene, polyisoprene, polychloroprene, poly (3-hydroxybutyrate) , Poly-3-hydroxyvalerate, polylactic acid, poly ε-force prolacton, polyethylene succinate, polybutylene succinate, polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate Polyamide 1-4 Polycyclohexylene dimethylene terephthalate, Polyamide 6, Polyamide 12, Polyamide 46, Polyamide 66, Polyamide 610, Polyphenylene terephthalanolamide, Polymetaphenylene diisophthalamide, Polyoxymethylene, Polyethylene Koxide, Polyphenylene oxide, Polyphenylene sulfide, Polyethersulfone, Polyetheretherketone, Polydimethylolsiloxane, Polycarbonate, Polyurethane, Polyimide, Epoxy resin, Urine Examples thereof include powders of an organic resin, a melamine resin, a phenol resin, an unsaturated polyester resin, acrylonitrile monobutadiene styrene, styrene acrylonitrile, ethylene acetate vinyl, and the like. Natural rubber latex, styrene butadiene rubber latex, nitrile rubber latex, chloroprene rubber latex, isoprene rubber latex, DPL (depolymerization latex), EPDM (ethylene propylene rubber), acrylic emulsion, polyurethane latex, etc. The latex is also a preferred example.

[0072] Examples of the food powder include boiled and dried, kelp, sesame or cherry shrimp, or powder such as wheat flour, udon powder, buckwheat flour, coffee powder or tea powder. Examples include flour. Examples of other organic particles include paper and grass powder.

 (1-3_3) Deodorant, Deodorant (E)

 In addition, a deodorant or a deodorant (E) may be added to the powdery oxygen absorbent of the present invention during or after production. This is because a decomposition reaction occurs when the oxidation reaction of the thermoplastic resin (A) proceeds, which may generate malodors such as low molecular weight aldehydes, ketones, esters, etc., and is suitable for removing such odors. It is.

 [0073] Examples of the deodorizer include activated carbon, zeolite, amorphous silica, cyclodextrin, sepiolite, ceramics, silica gel, and the like, which are obtained by chemically treating activated carbon with a substance such as amines, for example, manufactured by Nippon Environment Chemicals Co., Ltd. The granular birch GAAx is a preferred example.

 [0074] Deodorants include polyalkylene imines such as polyethyleneimine, vitamin E, tocophenol, titanium oxide, hydrazine derivatives, ammine compounds (pentaethylenehexamine, triethylenetetramine, polybuluoxazoline, Etc.), inorganic base compounds (calcium oxide, calcium hydroxide, calcium carbonate, etc.), flavonoid deodorants, polyphenol, turpentine oil, active aluminum oxide, magnesium silicate, aluminum silicate, etc.

[0075] The structure of the powdery oxygen absorbent of the present invention will be described below.

 (2-1) Shape

The oxygen absorbing material of the present invention is powdery. Here, the powdery state means “Kona-like state (Iwanami Shoten "From Kanjitsu 2nd edition)", Kona means "Smashed and crushed. Powder (From Iwanami Shoten 2nd edition)". As long as it is in powder form, it may be in any form such as powder form, fine particle form, granular form, spherical form, plate form, columnar form, cylindrical form, needle form, granular form, flake form, fibrous form, etc. A shape such as a powder, a fine particle, a plate, a needle, or a flake is easy to come into contact with.

 (2-2) Specific surface area

The powdery oxygen absorber of the present invention has a specific surface area force of 60 cm ² Zg or more, preferably 600 cm ² / g or more, more preferably, from the viewpoint of the effective surface area that should contribute to oxygen absorption, by the Kr gas adsorption method. More than 2000cm ² Zg.

 (2-3) Particle size

 The powdered oxygen absorbent material of the present invention was obtained by the method described later for reasons such as the oxygen absorption performance of the powdered oxygen absorbent material, ease of handling, and difficulty in powder leakage when placed in a sachet. The average particle size is generally from 0.01 / im to 5 mm, preferably from 0.01 μΐη to 1ιηπι.

 [0076] In the powdery oxygen absorbent material which does not contain the fine particles (D) and is composed of the thermoplastic resin (Α) and the oxidation accelerator (Β), the primary particle diameter is about 0.01 to about 10 μΐη, preferably Is from 0.01 μ ΐη to 5 / ι m. Further, a structure in which these primary particles are aggregated to form aggregated particles (aggregated structure) is preferable from the viewpoint of oxygen absorption performance and structural stabilization. The average particle size of the aggregated particles is generally 0.01 / im to 5 mm, preferably 0.1 / im to 3 mm, and more preferably 1 / im to 1 mm. In particular, a structure in which at least a part of primary particles having a relatively small particle size of 0.1 μΐη or less is located on at least a part of the surface of a relatively large primary particle having a particle size of about 10 / im. If it exists, it becomes easier to maintain the structure of the powdery oxygen absorber.

[0077] In the powdery oxygen absorbent containing fine particles (D), the primary particle diameter of the main agent composed of the thermoplastic resin (A) and the oxidation promoting component (B) is about 0.01 to 111111, preferably Is from 0.02 to 100 zm, more preferably from 0.05 to lO xm. The average particle diameter of the aggregated particles is usually 0.01 μπι to 5ιηιη, preferably 10 μm to 5 mm, and more preferably 10 μm to 3 mm. [0078] Hereinafter, a preferred method for producing the powdery oxygen absorbent material of the present invention will be described.

[0079] The method for producing a powdery oxygen absorbent according to the present invention comprises the following steps (X), (Y), (Z), (S), (X), (Y) or (X), (Y ), (Z) or (X), (Z), (Y) or (X), (Y), (S) or (X), (S), (Y) or (X), (Y ), (Z), (S) or (X), (Y), (s), (z) or (X), (Z), (Y), (S) or (X), (S), (Y), (Z) or (X), (Z), (S), (Y) or (X), (S), (Z), (Y) are preferably performed in this order.

 Step (X): a step of mixing the thermoplastic resin (A) and the oxidation promoting component (B),

Step (Y): Step of making the above mixture into a powdery shape with a specific surface area of 60 cm ² / g or more Step (Z): Radiation of ² kg or more of the above mixture or the powdered shape Exposure to and / or heating,

 Step (S): Step of storing the mixture or powdered product in a low-oxygen atmosphere Hereinafter, each step will be described in detail.

 (3-1) Process (X)

 The step (X) in the present invention is a step in which the thermoplastic resin (A) and the oxidation promoting component (B) are physically stirred or dissolved by heat, a solvent or the like and mixed.

 [0080] As described above, this step (X) may be omitted when only a trace amount of the polymerization catalyst remaining in the thermoplastic resin (A) becomes an effective oxidation catalyst.

 [0081] Further, as described above, it is preferable that the antioxidant polymer (C) is contained in an amount of 50 ppm to:! OOOppm relative to the thermoplastic polymer (A). Antioxidant (C) is added to, and if it is too much, antioxidant (C) is reduced. In order to reduce the antioxidant (C), the thermoplastic resin (A) is dissolved in a good solvent of the thermoplastic resin (A), and then the thermoplastic resin (A) is a poor solvent and oxidized in the next stage. Examples thereof include a method in which a substance that is a good solvent for the inhibitor (C) is added to precipitate only the thermoplastic resin (A), a so-called dissolution reprecipitation method, an extraction method using a Soxhlet extraction apparatus, and the like. When the oxidation promoting component (B) is added, it may be added before or after the separation step of the antioxidant (C), but it is preferable to add it after.

[0082] A preferred method and method of step (X) is a method of melt-mixing the thermoplastic polymer (A) and the oxidation promoting component (B) in a heated and melted state. [0083] As a concrete method for melting, melt-blending and mixing, there are thermothermoplastic plastic resin resin ((AA)), acid Add the oxidation promotion promoting component ((BB)) to the specified blending ratio, and if necessary, add other additions. In addition to the objects, use Henchen Schermi-Mixixar, Reribobon Blender, VV Type Blender, etc. to mix evenly and uniformly. After mixing, such as Baban Bambari-ri Mixer, Ninida Dader, Roller, Single-shaft or Double-Two-shaft, etc. A method for mixing and kneading using a kneading and kneading machine can be illustrated as an example. .

 [0084] In order to disperse and disperse the acid oxidation promotion promoting component ((BB)) evenly when mixing uniformly. In addition, fluid flow dynamic paraffins (for example, Susumoiiruru, etc., manufactured by Matsumatsumura-Muraishi Petroleum Institute, Ltd.), Mine Mineral Lulu Oil, etc. May be added. .

[0085] The temperature of the kneading and kneading of each component is determined by the temperature at which the thermothermoplastic plastic-polymer composite ((AA)) is in a melt-melt-melt state. It would be fine if the temperature was correct, but it would be possible to take into account such factors as the deterioration of resin resin fats and the use of bridge bridges to make Gegerl. It would be desirable if it is less than 228800 ° CC for preference and less than 225500 ° CC for more preference. . Furthermore, the order of mixing and kneading order of each component and the method of mixing are the following: Thermothermoplastic plastic-polymerized polymer ((AA)), Promotion of acid oxidation promotion A method of mixing the kneaded ingredients ((BB)) and other other ingredients together and kneading and kneading, ((AA)), ( (BB)) After mixing and kneading a part of the other components, the remaining components including other components are included. Examples of how to knead and knead the ingredients can be illustrated by examples. .

 ((33-22)) Process schedule ((YY))

The process ((YY)) in the present invention means the thermothermoplastic plastic polymer composite ((AA)) and acid oxidation as described above. Mixing and mixing the mixture of the accelerating and promoting component ((BB)) in the process of the polymerization polymerization process as will be described later. According to other methods such as the method of obtaining a compound, etc., the powder with a specific surface area of 6600ccmm ²² // gg or more This is the process of forming a powdery shape. . Examples of the shape and shape of the above-mentioned mixed mixture are, for example, peperretto-like, sushitoto-like, film-like, liquid-liquid, lump-like, cotton-like Examples include shapes, fibers, fibers, beverles, slab rubs, flakes, kukuramram, and powderer. .

 [0086] The powdered soot according to the present invention is, for example, the Atotomize method, the Memelrutos spippining method, the rotating rotating electrode method Cool with a cold refrigerant medium such as pulverized powder by mechanical and mechanical process, powdered powder by chemical process and liquid nitrogen nitride. A powder powder manufacturing method such as a method of pulverizing and pulverizing the powder ((freeze-freezing and pulverizing and pulverizing method)), etc. can be used. . Examples of methods that can be used as desired are the powder pulverization method and the freeze-frozen and pulverized powder pulverization method by mechanical mechanical processing. .

[0087] As a method of pulverizing and pulverizing according to mechanical and mechanical processes, for example, for example, Jojo Clarashasher, Loro Lulu Mimir, Kakatta Tami Mi Lulu, Hahan Mamma Mi Milulu, Pippin Mi Minorelle, Ato Toma My Isaichi, Bobono Norre Mimino Norre, Planetary Bobo Lurumi LULU Graly indander, stone millstone, cold-frozen frozen powder crushed system system, nitrogen nitrogen gagasu powder crushed system system, chemical chemistry powder crushed system Soot

[0088] Further, as a method of obtaining a mixture in the polymerization step, a method of producing by suspension polymerization, a method of producing by emulsion polymerization, and a solution in which a polymer produced by solution polymerization is dissolved in a medium such as water. Examples of the preferred method include emulsion polymerization and the like.

 (3-3) Process (Z)

 The step (Z) in the present invention is a step in which the mixture or the powdery product is exposed to radiation of at least 2 chloroplasts and Z or heated.

 Here, the radiation includes ionizing radiation such as gamma rays, X-rays, alpha rays, beta rays, electron rays, acceleration ions, neutron rays, preferably gamma rays and electron rays. Gamma rays are preferred.

 [0090] The absorbed dose is usually at least 2 kGy or more, preferably 5 to 1000 kGy, more preferably 20 to 300 kGy. Treatment with less than 2 kGy does not shorten the induction period much, and if it exceeds 10 OOkGy, there is a high possibility that the oxygen absorption performance will decrease due to the generation of gel due to the crosslinking reaction, and the productivity will decrease. Become.

 [0091] Examples of the method of exposure to radiation include, for example, the above mixture or a powder-like product in a degassed state or nitrogen, carbon dioxide and a mixed gas thereof, and, if necessary, oxygen at a partial pressure of less than 20%. Examples include a method of exposing to radiation in a container or bag in a state filled with an inert gas such as a gas mixed in (1).

 [0092] The heating temperature varies depending on the heating time. Generally, the heating temperature is 100 ° C to 300 ° C, preferably 110 ° C to 200 ° C. When the treatment is performed at a temperature lower than 100 ° C, the induction period is not shortened so much, and when the temperature exceeds 300 ° C, thermal decomposition or fusion of the above-mentioned mixture or powdered oxygen absorbent occurs, resulting in a decrease in productivity. Is likely to occur. The heating time is generally 0.1 second to 1 hour, preferably 0.5 second to 30 minutes, more preferably 1 second to 10 minutes.

 [0093] The heating method may be, for example, a method in which hot air of an inert gas is directly blown onto the mixture or the oxygen absorbent material in a powder form, a degassing state or a state in which the inert gas is filled, Examples of the method include heating in a bag and vacuum heating.

(3-4) Process (S) The step (s) in the present invention is a step of storing the above mixture or the powdered product in a low oxygen atmosphere.

 Here, “preserving in a low oxygen atmosphere” means, for example, packaging using a barrier packaging material, and using an inert gas replacement method and Z or other deoxidizing material as necessary. The powdery oxygen absorbing material is a step of storing it in a low oxygen concentration atmosphere. Here, the low oxygen concentration means that the oxygen concentration is less than 20%, preferably less than 5%, and more preferably less than 1%. This step (S) is preferable because it has the effect of shortening the induction period of the powdered oxygen absorber.

 [0095] The storage period varies depending on the storage temperature, the components constituting the powdered oxygen absorber and the production method, but is generally 1 day to several years, preferably 3 days to 6 months. More preferably, it is 1 week to 3 months. The treatment period of less than 1 day does not shorten the induction period so much, and if it exceeds several years, there is a high possibility that adhesion of powdery oxygen absorbers and a decrease in productivity due to an extended inventory retention period will occur. Become. As an example of a preferable storage period, for example, when the thermoplastic polymer (A) is a styrene / butadiene copolymer, it is 20 days, and this length is the same as the stock storage period when the powdered oxygen absorbent is distributed. Therefore, stock storage at the time of distribution also serves as the step (S) and is particularly preferable.

 [0096] The temperature during storage is generally 0 ° C to 100 ° C, preferably 5 ° C to 80 ° C, more preferably 10 ° C to 60 ° C. When the treatment is performed at a temperature lower than 0 ° C, the induction period is not shortened so much, and when the temperature exceeds 100 ° C, the oxygen absorbing materials are fused with each other, and the possibility that productivity is lowered is increased.

 [0097] Among the combinations of these steps, the thermoplastic polymer (A) and the oxidation promoting component (B) are melt-mixed in a heated and melted state (X), the molten mixture is pulverized (Y), the melt A method for producing a powdery oxygen absorbent comprising the step (Z) of exposing the mixture or pulverized product to gamma rays of 2 kg or more and the step (S) of storing the molten mixture or pulverized product in a low oxygen atmosphere is particularly preferred. It is an example.

[0098] Next, the powdered oxygen absorbing material of the present invention is used as a deoxidizing material in the form of being powdered and placed in a breathable sachet, or a compression molded piece or a piece mixed with a thermoplastic resin. Can be used as a deoxidizing material in the form of a sachet, used as a deoxidizing material in the form of a label, card, packing, etc., or mixed with a thermoplastic resin to deoxidize films, sheets, etc. The raw packaging material can be used in various forms for some or all of packaging bags and packaging containers.

 [0099] When the deoxidized material is placed in a breathable sachet, polyethylene, a copolymer of propylene and olefin, an ethylene monobutyl monomer copolymer, polypropylene, polystyrene, a copolymer of styrene and olefin, Examples thereof include a state in which an oxygen absorbing material is encapsulated in a polymer such as polyester, which has a large oxygen permeation amount, or a sachet made of paper, non-woven cloth, fine cloth, microporous film, or a multilayered body thereof. In addition, the sachet may be perforated from the viewpoint of air permeability.

 [0100] In the case of a film or sheet, it may be composed only of the layer (L1) containing the powdery oxygen absorber, but at least one layer (L2) or more composed of other materials. Even a laminated film composed of L2 is composed of thermoplastic polyester resin, thermoplastic polyurethane resin, thermoplastic polyolefin resin (LDPE (low density polyethylene), VLDPE (very low density polyethylene), LLDPE (linear low density polyethylene), HDPE). (High-density polyethylene), propylene resin, butene-1 resin, etc.), polyamide resin, polyvinyl chloride, styrene resin, ethylene acetate copolymer, ethylene (meth) alkyl acrylate copolymer, ethylene (meta ) Acrylic acid copolymer and ethylene (meth) acrylic acid ionomer.

 [0101] Further, a laminated film obtained by laminating a layer (L3) having an oxygen barrier property on the powdery oxygen absorbing material-containing layer (L1) is a preferred embodiment. L1 is configured to be positioned closer to the package than L3. L3 includes EVOH (ethylene-vinyl alcohol copolymer), PVDC (polyvinylidene chloride), PET (polyethylene terephthalate), PBT (polybutylene terephthalate), PTT (polytetramethylene terephthalate), PEN (polyethylene naphthalate). ), PVA (polybutyl alcohol), PAN (polyacrylonitrile), PA (polyamide) and copolymers thereof, and the like, and a resin composition containing an inorganic layered compound such as clay may be used. The film surface or intermediate layer may be coated with a barrier organic material or an inorganic material such as alumina, silica or amorphous carbon.

[0102] The powdery oxygen absorber of the present invention can be applied to food, medicine, test kits, medical equipment, iron pipes, capacitors, dry batteries packaging, bottle cap seals, labels, etc. The

 Example

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

 First, the measurement method and evaluation method used in the present invention are summarized below.

 <Various viscosity>

 The viscosity of the powdery oxygen absorber of the present invention (ML1 + 4Z100 ° C) was obtained by adding 250 g of toluene to 30 g of the powdered oxygen absorbent of the present invention and dissolving it, and removing unnecessary components with a glass filter or the like. Thereafter, methanol lOOOg was added to this solution and reprecipitated to separate the thermoplastic resin (A) from the powdery oxygen absorber, and 35 ° C using a vacuum dryer DP63 (trade name) manufactured by Yamato Scientific Co., Ltd. Then, after drying for 48 hours in vacuum, using a murine and viscometer MVR-1130 (trade name) manufactured by Ueshima Seisakusho, preheating time 1 minute according to JIS K6300, rotor rotation time 4 minutes, The measurement was performed at a test temperature of 100 ° C.

 <Crystal melting peak (melting point) and crystal melting energy>

 The crystal melting peak (melting point) of the powdered oxygen absorber of the present invention was determined by adding 250 g of toluene to 30 g of the powdered oxygen absorber of the present invention and dissolving it, removing unnecessary components with a glass filter etc., and then adding methanol to this solution. lOOOg is collected and re-precipitated to separate the thermoplastic resin (A) from the powdered oxygen absorber and vacuum dried at 35 ° C for 48 hours using the Yamato Kagaku vacuum dryer DP63 (trade name). Using a Perkin Elmer differential scanning calorimeter “PYRI S DIAMOND DSC” (trade name), approximately 10 mg of a sample between _50 ° C and 200 ° C according to JIS K7121 Temperature is increased at a rate of 10 ° C / min, held for 5 minutes, then from 200 ° C to 50 ° C, the temperature is decreased at a rate of 10 ° C / min, and further maintained for 5 minutes _ 50 ° C The crystal melting peak temperature of the DSC curve obtained at the second temperature increase from 10 to 200 ° C at a rate of 10 ° CZ was used.

[0104] Further, in accordance with JIS K7122, the energy per unit weight of the area surrounded by a straight base line drawn from the melting start temperature to the melting end temperature on this DSC curve was defined as the crystal melting angle 军 energy.

 <Specific surface area>

The specific surface area of the powdered oxygen absorber of the present invention is a pore distribution / specific surface area manufactured by Shimadzu Corporation. Using the measuring device ASAP-2010 (trade name), the powdery oxygen absorbent material of the present invention is taken in a standard cell and degassed at a temperature of 35 ° C for about 6 hours in the sample pretreatment section of the device. Measurements were made using the BET approximation by the Kr gas adsorption method.

 <Average particle size>

 The average particle size was determined by randomly selecting 50 particles using the results of observation of secondary electrons in high vacuum mode with JEOL's scintillation electron microscope i¾JSM_5600LV (trade name).

Then, the diameter of a circle having the same area as the area occupied by each particle in the photograph was obtained, and the simple average value thereof was obtained.

 [0105] The average particle size required is the average particle size of the aggregated particles, not the average particle size of the primary particles.

 Saturated oxygen absorption (Vos)>

A sample of about 0. lg of powdered oxygen absorbent, the wall thickness is oxygen permeation amount 30 cm ³ / at ^{80 xm (m 2 'day'} MPa) less than a is polyvinylidene chloride made barrier with the volume of 200 cm ³ The container was sealed and replaced with a mixed gas having an oxygen capacity of 21% and nitrogen of 79% by volume. After that, place these containers under conditions of a temperature of 23 ° C and humidity of 17% RH, and monitor the time-dependent changes in oxygen concentration in the containers using the PBI gas concentration measuring device Dansensor CheckMate9900 (trade name). The oxygen absorption amount was calculated. The oxygen absorption per lg oxygen absorber when the oxygen concentration reached saturation was defined as the saturated oxygen absorption (Vos, unit: cc / g).

 <Maximum oxygen absorption rate (Ros), induction period>

 In the curve (oxygen absorption curve) with the oxygen absorption obtained by the above oxygen absorption measurement method on the vertical axis and the elapsed time on the horizontal axis (oxygen absorption curve), the maximum slope is the maximum oxygen absorption rate (Ros, unit Was defined as ccZ (g 'hr)).

[0106] Further, in the above oxygen absorption measurement method, the period (unit: hr or day) from the start of measurement until the oxygen concentration in the container was 20.6% or less was defined as the induction period.

 <Quantification method of antioxidants>

Add antioxidant to 3g of powdered oxygen absorber as standard, reprecipitate chlorophenol / methanol, concentrate the filtrate to dryness, solidify to 10ml with methanol, and remove sampnore. Created. Using this liquid chromatograph 600 (trade name) manufactured by Waters, the sample was Microbonder Pack C18 as a column, methanol: water = 80:20 (start), linear gradient (0-5 minutes), Methanol: water = 100: 0 (5 to 20 minutes), flow rate is lml / min, injection volume is 30 μ1, and the detector is Waters UV detector 996 (trade name) (detection wavelength 285 nm) The liquid chromatograph was measured by the standard addition method.

[Example 1]

Polybutadiene rubber manufactured by Asahi Kasei Chemicals Co., Ltd. having a Mooney viscosity of 55. Gen 55AE (trade name) (hereinafter abbreviated as BR), 25 g of toluene as a good solvent was added to 3 g and stirred well to completely dissolve. Next, 250 g of methanol as a poor solvent was added while stirring well to precipitate the polymer mass, the supernatant liquid was removed using filter paper, and this operation was repeated three times to obtain a precipitate. BR obtained by the above-described dissolution and reprecipitation method as thermoplastic resin (A) is dissolved in 12 g of toluene, and naphthenic acid cobalt 0 · 05 g (0% as cobalt atom) manufactured by Wako Pure Chemical Industries, Ltd. is used as oxidation promoting component (B). - what was stirring well with the addition of 1 wt _^0/0), placed in a glass petri dish with a diameter of 8.5 cm, by Ri at 35 ° C in Yamato scientific Co., Ltd. of vacuum dryer DP63 (trade name), 48 By vacuum drying for a time, a transparent sheet having a thickness of about 300 μm was obtained. Next, using a freezer mill SPEX6700 (trade name) manufactured by SPEX, the sheet lg was placed in a pulverizing tube filled with nitrogen gas, cooled with liquid nitrogen for 10 minutes, and then freeze-ground for 5 minutes. A powdery oxygen absorber was obtained. This powdery oxygen absorbent material was a white solid powder and did not stick even when returned to room temperature, and had a shape that was easy to handle. Further, when the powdery oxygen absorbing material was observed with a scanning electron microscope, it was found that particles having a size of several μm to about 1000 μm were mixed. Further, when the particles were further enlarged, it was observed that primary particles of about 0.5 / im to about 5 μm aggregated. The structure in which such small and large particles coexist and fine particles aggregate together keeps the contact area with oxygen large and prevents adhesion between powders, contributing to excellent oxygen absorption performance. It is considered a thing. The powder oxygen absorber had a specific surface area of 2,920 cm ² / g and an average particle size of 0.95 mm. DSC measurement of the powdery oxygen absorber did not have a crystal melting peak. The powdery oxygen absorber was completely dissolved within a day after soaking in toluene to the extent that it did not retain its original shape and was not substantially crosslinked. [0108] The powdery oxygen absorber was evaluated by the above method. As a result, Vos = 230cc / g, Ros = 38cc / (g'hr), and an excellent oxygen absorption amount and oxygen absorption rate were exhibited. It was.

 [0109] Further, the powdery oxygen absorber lg and activated carbon granular white birch GAAx manufactured by Nippon Enviguchi Chemicals

 (Product name) 0.5 g filled in a sachet made of bag material with an air permeability of 8,000 seconds in accordance with the Gurley tester method (iIS _P_ 8117) (hereinafter referred to as sachet sample) Omi Air Air Service Co., Ltd. Sampling Bag. Flex Sampler F (trade name) was placed on the air and filled with air to absorb oxygen and sniff the air in the bag a day later. However, no unpleasant odor was felt. The formaldehyde detector FP_30 (trade name) manufactured by Riken Keiki Co., Ltd. was used to measure the formaldehyde in the air in the bag, and it was below the detection limit (0. Olppm).

 [0110] In addition, the Dora-yaki weighing about 80 g and the above sachet sample are sealed in the above sampling bag, and after one day, the oxygen concentration in the barrier bag is measured and the odor of the air in the bag is smelled. The oxygen concentration was 0.1% and the sachet Sampnole absorbed oxygen and did not feel an unpleasant odor. In addition, the Dora-yaki and small sachet samples are sealed in a barrier bag made of PP / PA / EVOH / LL DPE and left for a day to measure the oxygen concentration in the barrier bag (0.1%). After heating in a microwave oven, I smelled the odor of the air in the bag.

 [Comparative Example 1]

 Following the production method of Example 1 of Patent Document 1, 0.5 g of liquid polybutadiene having a molecular weight of 10,000 and a viscosity of less than 5 is 0.5 g, 0.5 g of soybean oil manufactured by Wako Pure Chemical Industries, Ltd. A mixture of 0.2 g of cobalt naphthenate manufactured by Yakuhin Kogyo Co., Ltd. is impregnated in 5 g of activated carbon manufactured by Wako Pure Chemical Industries, Ltd., and 0.5 g of slaked lime is applied to the surface of the impregnated activated carbon to absorb powdered oxygen. Made the material.

[0111] The powder oxygen absorber was evaluated by the above method. As shown in Fig. 1, Vos = 41cc / g, Ros = lccZ (g'hr), and the powder oxygen of the present invention. It was inferior to the absorbent material. As described above, when components having a Mooney viscosity of less than 5 and lower than the Mooney viscosity of the present invention are used for the oxygen absorption reaction, it is easy to reattach the powders to each other, or oxygen such as a carrier. If the main component contains components unrelated to the absorption reaction, The oxygen absorption capacity and oxygen absorption speed were lower than the oxygen absorbent material of the present invention due to the reason that the oxygen absorption performance was relatively low.

 [Comparative Example 2]

In the mixing process of Example 1, in addition to 0.05 g of cobalt naphthenate, organic peroxide di- 2 _t_butylperoxyisopropylbenzene (trade name: perbutyl P) 0.3 g from Nippon Oil & Fats Co., 60 ° A mixture was prepared in the same manner except that it was mixed at C. The mixture was heated at 180 ° C. for 10 minutes in a nitrogen-substituted container and then cooled. This was pulverized in the same manner as in the pulverization step of Example 1 to prepare a powdery oxygen absorbent. This powder oxygen absorber had a viscosity of more than 400 and could not be measured. It did not dissolve at all in toluene. The powder oxygen absorber had a specific surface area of 2,850 cm ² Zg and an average particle size of 0.82 mm.

[0112] The powdery oxygen absorber was evaluated by the above-described method. As a result, Vos = 132cc / g and Ros = 14ccZ (g'hr). As described above, the oxygen absorption amount is reduced because the double bond necessary for the oxygen absorption reaction is reduced or the molecular motion is restricted due to the cross-linking of the powdery oxygen absorber. The oxygen absorption rate was lower than that of the oxygen absorbing material of the present invention.

 [Comparative Example 3]

 According to the production method of Example 1 of Patent Document 3, a powdery oxygen absorbent was prepared from 0.8 mmol of naphthenic acid cobalt salt, 2.4 mmol of triethylaluminum, 240 ml of butadiene, and 1.6 mmol of carbon disulfide. The powdery oxygen absorber had a spherical shape with a diameter of 200 μΐη, a melting point of 147 ° C., and a Mooney viscosity exceeding 400, which was not measurable.

[0113] When the powdery oxygen absorbent was evaluated by the above method, Vos was 18 cc / g and Ros was substantially zero.

[0114] Thus, in the powdery oxygen absorber having a melting point of 147 ° C, which is higher than the melting point of the powdery oxygen absorber of the present invention, the amount of oxygen absorbed due to the reason that molecular motion is limited. The oxygen absorption rate was lower than that of the oxygen absorbent material of the present invention.

 [Comparative Example 4]

As a result of evaluating the iron-based oxygen absorber AGELESS ZP-50 (trade name) manufactured by Mitsubishi Gas Chemical Company using the above method, Vos = 68cc / g and Ros = 18cc / (g'hr). [Example 2]

In Example 1, instead of 0.05 g of cobalt naphthenate, 0.03 g of silver oxide (1) 0.03 g (1.0% by weight as silver atoms) manufactured by Wako Pure Chemical Industries, Ltd. was used, and the oxygen absorbing material was used in exactly the same manner. Created. The powdery oxygen absorber had a specific surface area of 9,450 cm ² Zg and an average particle size of 0.78 mm.

 [0115] The powdered oxygen absorber was evaluated by the above method. Vos = 153cc / g, Ros = 19ccZ (g * hr), and showed an excellent oxygen absorption amount and oxygen absorption rate. .

 [Example 3]

 In the mixing step of Example 1, for the BR obtained by the dissolution reprecipitation method, as a antioxidant (C), a phenolic antioxidant manufactured by Ciba 'Specialty' Chemicals · IRGANOX 1076 (trade name) (octadecyl) 1- (3,5-di-tert-butyl-4-hydroxyphenyl) propylene disulfide) added to 260ppm, 650ppm, 1300ppm, 1800ppm, added by Sumitomo Chemical Co., Ltd. In the same manner as in Example 1, the amount of added calorie of the Zio-based antioxidant 'Sumilizer TPS (trade name) (distealino reci-gi diplopi genius 卜-卜) was changed to 100 ppm, 250 ppm, 500 ppm, 180 Oppm. A powdery oxygen absorber was prepared. Their specific surface area and average particle diameter were substantially the same as those in Example 1.

 [0116] When the powdery oxygen absorber was evaluated by the above method, all samples had Vos of about 230 cc / g and Ros of about 38 cc / (g-hr).

 [0117] Here, the induction period of these powdery oxygen absorbers is shown together in Fig. 2, and the induction period can be controlled by the antioxidant (C).

 [0118] Fig. 2 is a graph in which the vertical axis represents the induction period of the powdery oxygen absorbent, and the horizontal axis represents the amount of antioxidant (C) added. In the figure, “♦” indicates that the phenolic antioxidant is added, and “Mouth” indicates that the phenolic antioxidant is added.

 In FIG. 2, the induction time can be controlled by adding the antioxidant (C).

[0120] In particular, in the case of the phenolic antioxidants marked with "♦" in the figure, a linear relationship is observed between the amount of the phenolic antioxidant added and the induction period, and the desired induction time is controlled. It turns out that it is easy. In the case of phenolic antioxidants, the amount added is 50 ~: 1, In case of OOOppm, the induction period is about 3 hours to 3 days.

 [Example 4]

 According to the manufacturing method of SB rubber latex in Example 2 of JP-A-05-017507, 1,3-butadiene 18.0 parts by weight, Atalilonitrinore 2.0 parts by weight, t-dodecyl mercaptan 0.1 Parts by weight, disproportionated potassium rosin acid salt 0.067 parts by weight, beef tallow saponified fossil sapon 0.03 parts by weight, sodium persulfate 0.075 parts by weight, caustic soda 0.03 parts by weight, sodium bicarbonate 0.10 parts by weight 60.0 parts by weight of ionic water was put into an autoclave whose inside was evacuated to vacuum, and polymerized at 65 ° C. by an emulsion polymerization method.

 [0121] Initiation of polymerization 2. 5 hours power 5 hours over 1 hour, 1,3_butadiene 70.0 parts by weight, styrene 10.0 parts by weight, t-dodecyl mercaptan 0.3 parts by weight, disproportionation Rosin acid potassium salt 0.67 parts by weight, beef fat saponified fossil ken 0.33 parts by weight, sodium persulfate 0.1 parts by weight, caustic soda 0.05 parts by weight, sodium bicarbonate 0.15 parts by weight, oxidized 0.5 parts by weight of zinc naphthenate (product name: naphthex Zn8% T) manufactured by Nippon Kagaku Sangyo Co., Ltd. as the accelerating component (B) and 50.0 parts by weight of deionized water Were polymerized with continuous addition to the autoclave to produce a powdery oxygen absorbent.

[0122] The average particle size of the powder-like oxygen-absorbing material 3. 5 / im, the specific surface area is 19, 500cm ² / g, the melting point had no. Further, the powder oxygen absorber had a viscosity of 80. The dried powdery oxygen absorber was evaluated by the above method. As a result, Vos = 140cc / g, Ros = 26cc / (g′hr), and an excellent oxygen absorption amount and oxygen absorption rate were exhibited. It was.

 [Example 5]

Wako Pure Chemical Industries Co., Ltd. Cobalt Naphthenate Co. 1.67% by weight (0.1% by weight as cobalt atom) to Asahi Kasei Chemicals Co., Ltd. After mixing until uniform in a blender, these mixtures were melt-kneaded at 215 ° C using a twin screw extruder PCM_45 (trade name) manufactured by Ikekai Tekko. The strand-shaped resin composition coming out of the die is water-cooled, then cut into pellets using a water-cooled pelletizer KN-150 (trade name) manufactured by Katsu Seisakusho, and then placed in an oxygen barrier bag. Stored sealed. Next, the pellets were pulverized using a disc grinder pulverizer GPC_140 (trade name) manufactured by Nishimura Machinery Co., Ltd. Created. This powdery oxygen absorbing material was a light blue solid powder and did not stick even when returned to room temperature, and had a shape that was easy to handle. When this powdery oxygen absorber was observed with a scanning electron microscope, it had a structure in which particles having a size of about 20 μm to about 1 mm were mixed. Further, when this particle was further enlarged, it was observed that primary particles of about 0.5 zm to about 20 zm aggregated. The powdery oxygen absorber had an average particle size of 0.78 mm and a specific surface area of 2,400 cm ² Zg. Further, the content of the antioxidant in the powdery oxygen absorbent was analyzed by the above-mentioned method and found to be 410 ppm. DSC measurement of the powdery oxygen absorber showed no crystal melting peak.

 [0123] The powdery oxygen absorber was deaerated and packaged in an oxygen barrier bag made of EVH / Ny, and irradiated with 240 kGy of Kobanoleto-60 gamma rays. After the irradiation, the viscosity of the powdery oxygen absorbent was measured and found to be 165.

 [0124] When the powdery oxygen absorber was evaluated by the above method, Vos = 102cc / g, Ros = 20cc / (g'hr), induction period was 4 hours, and excellent oxygen absorption amount And the oxygen absorption rate.

 [0125] When the powdery oxygen absorber was left in the atmosphere at 25 ° C and relative humidity 20% RH for 4 hours and then evaluated by the above method, the amount of oxygen absorbed and the rate of oxygen absorption changed. Natsuki.

 [Example 6]

 Implementation An oxygen absorbent was prepared in exactly the same manner as in Example 5, except that the gamma, line f, and amount of fountain were changed to 30 kGy, 120 kGy, and 500 kGyi. The powder viscosities of the powdery oxygen absorbers were 135, 150, and 180, respectively. The powdered oxygen absorbers were evaluated by the above method. These oxygen-absorbing materials had a Vos of approximately 102cc / g and a Ros of approximately 20cc / (g-hr). The power that was not.

[0126] On the other hand, the induction period is 30, 120, 240, and 500, while the induction period is 24 hours, 8 hours, 4 hours, and 0.5 hours, respectively. It was found that the induction period can be controlled easily.

 [Example 7]

The powdered oxygen absorbing material of Example 5 was further deoxidized material Ageless ZP— It was deaerated and packed in an oxygen barrier bag made by EVOH / Ny with 200 (trade name) and stored at 40 ° C for 10, 20, 30, and 60 days. When the powdered oxygen absorber after storage was evaluated by the above method, Vos was approximately 102cc / g, Ros was approximately 20cc / (g'hr), and the force was not affected by the low oxygen atmosphere storage period. It was.

[0127] On the other hand, focusing on the induction period, the induction period is 4 hours, 2 hours, 1 hour, respectively for the low oxygen atmosphere preservation period 0 days, 10 days, 20 days, 30 days, 60 days. It was 1 hour and 1 hour, and the induction period became shorter as the low oxygen atmosphere preservation period became longer, and it became almost constant after 20 days.

 Industrial applicability

[0128] The powdery oxygen absorbing material of the present invention can be suitably used in the field of preservation of metal products, foods, pharmaceuticals, photographic films, old documents, pictures, electronic products and the like.

Claims

The scope of the claims

[1] Allyl hydrogen and Z or tertiary carbon with Mooney viscosity of 10 to 400 and no crystalline melting peak or melting point less than 75 ° C as measured by differential scanning calorimetry (DSC) A powdery oxygen absorbent comprising a thermoplastic polymer (A) having hydrogen bonded to the molecule and an oxidation promoting component (B) and having a specific surface area of 60 cm ² / g or more.

 [2] The powdery oxygen absorbent according to claim 1, wherein the thermoplastic polymer (A) has a viscosity of 20 to 150.

 [3] The powdery oxygen absorbent according to claim 1 or 2, wherein the thermoplastic polymer (A) is a polymer or copolymer containing 50% by weight or more of butadiene units.

 [4] The thermoplastic polymer (A) is a block or random structure copolymer comprising 50 to 99% by weight of butadiene units and:! To 50% by weight of styrene units. Item 4. The powdery oxygen absorber according to any one of Items 1 to 3.

 [5] The powdery oxygen absorbent according to any one of claims 1 to 4, characterized in that the thermoplastic polymer (A) contains 50-: OOOOppm of antioxidant (C).

 [6] The thermoplastic polymer (A), the oxidation promoting component (B), and the thermoplastic polymer (A) contain fine particles (D) that have adhesion but are difficult to adhere to each other. The particle size is 10 zm to 5 mm, and at least a part of the fine particles (D) is located on the surface of the powder (A) and (B) force. The powdery oxygen absorber according to crab.

 [7] A method for producing a powdery oxygen absorbent comprising the following steps.

 Step (X): Allyl hydrogen having a viscosity of 10 to 400 and having no crystal melting peak as measured with a differential scanning calorimeter (DSC) or having a melting point of less than 75 ° C. A process of melt-mixing a thermoplastic polymer (A) having hydrogen bonded to Z or tertiary carbon in its molecule (A) and an oxidation promoting component (B) in a heated and melted state.

 Step (Y): Step of pulverizing the molten mixture obtained in step (X)

 Step (Z): A step of exposing the molten mixture obtained in step (X) or the pulverized material obtained in step (Y) to radiation of 2 kyrogray or more.

 Step (S): A step of storing the molten mixture or powdered product in a low oxygen atmosphere.