WO2017203912A1 - Oxygen scavenger - Google Patents

Abstract

An oxygen scavenger including fluorite-type cerium oxide particles having a reversible oxygen deficiency represented by CeO_x (where x is a positive number less than 2), the surface of the particles being covered by an inorganic oxide. The inorganic oxide preferably comprises at least one substance selected from M_yO_z (where M represents an element that does not undergo a valence change, and y and z represent positive numbers) and a composite oxide of element M and cerium oxide. The inorganic oxide also preferably comprises at least one substance selected from SiO₂, Al₂O₃, a composite oxide of Si and Ce, and a composite oxide of Al and Ce.

Description

Oxygen scavenger

The present invention relates to an oxygen scavenger.

As a conventional technique using cerium oxide having oxygen deficiency as an oxygen scavenger, for example, one described in Patent Document 1 is known. This document describes a resin composition having oxygen absorbing ability, which contains cerium oxide having oxygen deficiency and a thermoplastic resin. This resin composition has not only the ability to absorb oxygen, but also is not affected by the contents, has microwave suitability, and is suitable as a packaging material with little change in physical properties due to oxygen absorption. It is described in the literature.

As another technique of using cerium oxide having oxygen vacancies as an oxygen scavenger, the present applicant has previously described the removal of cerium oxide having oxygen vacancies and a powder having a specific surface area of 0.6 m ² / g or less. An oxygen agent was proposed (see Patent Document 2). The present applicant further includes a fluorite-type cerium oxide porous body represented by CeO _x (x represents a positive number less than 2) and having reversible oxygen vacancies, and has a specific surface area of 0.1. An oxygen scavenger with a median diameter of 6 to 1.8 m ² / g and a pore median diameter of 1.6 to 5.3 μm was also proposed (see Patent Document 3).

JP 2005-105194 A JP 2007-185653 A US Application Publication No. 2011/0886757

However, in this type of oxygen scavenger, improvement in practicality is demanded, and an oxygen scavenger whose performance is further improved as compared with the resin compositions having oxygen absorbing ability described in Patent Documents 1 to 3 is desired. ing.

Therefore, an object of the present invention is to provide an oxygen scavenger that can eliminate the various disadvantages of the above-described prior art.

The present invention includes fluorite-type cerium oxide particles having a reversible oxygen deficiency represented by CeO _x (x represents a positive number less than 2), and the surface of the particles is covered with an inorganic oxide. It provides a conventional oxygen scavenger.

FIG. 1 is a cross-sectional view showing the structure of a package containing the oxygen scavenger of the present invention. FIG. 2 is a cross-sectional view in the thickness direction showing one embodiment of a deoxygenated film having a multilayer structure. FIG. 3 is a cross-sectional view in the thickness direction showing another embodiment of the deoxidized film having a multilayer structure. FIG. 4 is a diagram showing element mapping results of the inorganic oxide-coated cerium oxide obtained in Example 1. FIG. 5 is a diagram showing element mapping results of the inorganic oxide-coated cerium oxide obtained in Example 5.

Hereinafter, the present invention will be described based on preferred embodiments thereof. The oxygen scavenger of the present invention includes particles of cerium oxide having reversible oxygen vacancies represented by CeO _x (x represents a positive number less than 2). Cerium oxide having oxygen vacancies is a substance having oxygen absorption sites due to reversible oxygen vacancies generated by forced extraction of oxygen. It is generally known that there are two types of oxygen deficiency possessed by cerium oxide: reversible deficiency and irreversible deficiency. The reversible deficiency is an oxygen deficiency possessed by the cerium oxide used in the present invention, and is generated when oxygen is forcibly extracted by treatment under strong reducing conditions. A reversible defect is a defect in which oxygen can be taken into a deficient site. In cerium oxide having a reversible defect, an unbalanced state of electric charge caused by oxygen deficiency is compensated by reducing a part of tetravalent cerium to trivalent. Trivalent cerium is unstable and easily returns to tetravalent. Therefore, by incorporating oxygen into the deficient site, trivalent cerium returns to tetravalent, and the charge balance is always kept at zero. On the other hand, an irreversible defect is formed by doping a metal inorganic oxide with an element having a valence lower than that of the metal. An irreversible defect, unlike a reversible defect, is not a defect caused by treatment under strong reducing conditions. The irreversible defect can be obtained, for example, by mixing an oxide of an element having a valence lower than the valence of the metal with a metal inorganic oxide and firing in the atmosphere. When the metal inorganic oxide is cerium oxide, the valence of cerium in cerium oxide having irreversible defects is all tetravalent. Therefore, oxygen is not taken into the deficient site. For example, when 20 mol% of Ca is dissolved in CeO ₂ (Ce _0.8 Ca _0.2 O _1.8 ), the average valence of the cation is 4 × 0.8 + 2 × 0.2 = 3.6. Therefore, the number of oxygen atoms for balancing the charge of oxygen with this valence is 3.6 / 2 = 1.8, and the number of necessary oxygen atoms is less than two. Oxygen deficiency occurs accordingly. However, this oxygen deficiency is not capable of absorbing oxygen. Thus, the irreversible defect is not caused by forced extraction of oxygen but is caused by charge compensation in cerium oxide.

The cerium oxide contained in the oxygen scavenger of the present invention has an oxygen absorbing ability in the living environment atmosphere. Here, the living environment atmosphere refers to a general atmosphere when storing products such as foods, electronic parts, and pharmaceuticals. The atmospheric pressure includes, for example, a reduced pressure state (vacuum packaging or the like) in a product packaging, and a pressurized state (pressurization / heat sterilization in retort processing, packaging shape maintenance use, or the like). The temperature includes about −50 ° C. (during frozen storage) to 130 ° C. (retort treatment of food). Therefore, high-temperature and / or high-pressure harsh atmosphere such as exhaust gas discharged from a power engine operating with fossil fuel is not included in this living environment atmosphere.

The cerium oxide contained in the oxygen scavenger of the present invention has an oxygen absorption site because oxygen is forcibly extracted from the crystal lattice by the reduction treatment of CeO ₂ and becomes an oxygen deficient state (CeO _2-x ). . Since this cerium oxide has a fluorite-type crystal structure, it is structurally stable and can stably hold oxygen absorption sites due to oxygen vacancies. In addition, since the oxygen ion conductivity is high, oxygen can enter and exit the crystal, and the oxygen absorption ability is good.

The cerium oxide having oxygen vacancies is suitable by reducing CeO ₂ in a strong reducing atmosphere having a high concentration of reducing gas such as hydrogen gas, acetylene gas or carbon monoxide gas and high-temperature heat treatment. Is obtained. The concentration of the reducing gas is preferably not less than the lower limit of explosion to 100% by volume, more preferably not less than 20% by volume and not more than 100% by volume. The treatment temperature is preferably 500 ° C. or higher, more preferably 700 ° C. or higher and 1200 ° C. or lower, more preferably 1000 ° C. or higher and 1050 ° C. or lower. The strongly reducing atmosphere is generally atmospheric pressure, but pressure conditions may be used instead. If the reduction time is a reduction method with good contact efficiency with a gas such as a rotary kiln, cerium oxide having oxygen deficiency can be obtained by reduction for about 5 minutes or more and about 1 hour or less. On the other hand, in the case of a batch-type gas flow furnace, cerium oxide having oxygen deficiency can be obtained by reduction for about 1 hour or more and about 3 hours or less.

In the present invention, the cerium oxide may be used in the form of a composite oxide by adding a specific element to the cerium oxide having oxygen vacancies and replacing it with a solid solution. As a result, the oxygen absorption amount can be significantly increased. Examples of the specific additive element include one or more elements selected from the group consisting of magnesium, calcium, strontium, barium, lanthanum, niobium, praseodymium, and yttrium. Among these elements, the use of one or more elements selected from the group consisting of yttrium, calcium and praseodymium is particularly preferable because the oxygen removal performance is further increased. These additive elements can be added to cerium oxide, for example, in the form of an oxide when the cerium oxide powder is produced, and can be dissolved in cerium oxide. The total addition amount of the additive elements is preferably set to 1 mol% or more and 20 mol% or less with respect to the number of moles of cerium from the viewpoint of sufficiently exhibiting the addition effect.

The surface of the particles of cerium oxide having oxygen vacancies used in the present invention is covered with an inorganic oxide. The inorganic oxide is located on the surface of the cerium oxide particles in a state of particles having a smaller particle diameter than the cerium oxide particles. Inorganic oxide particles are cerium oxide particles by various forces such as chemical bonding force by sintering, intermolecular force (van der Waals force), mechanical engagement force (anchor effect), and adhesive force by binder. It can be fixed to the surface of. The inorganic oxide particles preferably cover the surface of the cerium oxide particles in the form of a coating. This film is not a dense film that completely blocks the permeation of oxygen molecules but has oxygen permeability.

On the condition that the permeation of oxygen molecules is not completely blocked, the inorganic oxide particles may cover the entire surface uniformly and continuously without exposing the surface of the cerium oxide particles. Alternatively, the surface may be discontinuously coated so that a part of the surface of the cerium oxide particles is exposed. The distribution state of the inorganic oxide particles on the surface of the cerium oxide particles can be measured, for example, by element mapping using EDX.

As a result of intensive studies on the deoxygenation action of a composition containing cerium oxide having oxygen deficiency and a resin, when heat is applied while the cerium oxide having oxygen deficiency is in contact with the resin, the catalyst of the cerium oxide It was found that due to the action, the dissociation of C—H bonds in the resin was promoted, thereby generating H ₂ gas. The generation of H ₂ gas can cause peeling between films when considering a laminate of a film containing cerium oxide and resin having oxygen deficiency and another film, for example. Alternatively, the generation of H ₂ gas can be achieved when a composition containing oxygen-deficient cerium oxide and a resin is incorporated in layers like a printed wiring board or the like, or adhered to an electronic device without a gap like an electronic device sealing material. Also when it is made, it can cause peeling.

In addition, when the present inventors melt-kneaded a composition containing cerium oxide having oxygen deficiency and a resin, the heat applied at that time causes oxygen atoms in the resin to be extracted by the cerium oxide, causing the resin to decompose, It has been found that the phenomenon of the resulting cracked gas and smoke occurs. Therefore, the present inventor has found that inconvenience is caused by kneading cerium oxide having oxygen deficiency with a resin containing oxygen atoms in the molecule and forming a resin composition.

As described above, the use of a combination of cerium oxide having oxygen vacancies and a resin causes various inconveniences. It was found that these difficulties can be overcome by covering with. This reduces the chance of cerium oxide having oxygen vacancies coming into direct contact with the resin, so that the C—H bond in the resin is dissociated to generate H ₂ gas, or the oxygen atoms are extracted from the resin. It is possible to effectively prevent generation of cracked gas and smoke.

From the viewpoint of making the above effects more remarkable, for example, a metal oxide or a non-metal oxide can be used as the inorganic oxide. The inorganic oxide may be an oxide of a single element, a composite oxide of two or more metals, a composite oxide of two or more non-metals, or one or more metals and one or more types of metal. A complex oxide with a nonmetal may be used.

In addition, as the inorganic oxide, it is allowed to use a composite oxide generated by a reaction between cerium oxide itself to be coated and an element covering the cerium oxide. This composite oxide is formed by reacting the coating with cerium oxide in the step of firing after the surface coating of cerium oxide with the coating and the step of reducing treatment. For example it is also possible to use a later-described inorganic oxide M _y O _z and cerium oxide is a composite oxide produced by the reaction, complex oxide of element M and of cerium oxide. Examples thereof include a complex oxide of Si (derived from SiO ₂ ) and Ce and a complex oxide of Al (derived from Al ₂ O ₃ ) and Ce. These composite oxides can be used singly or in combination of two or more.

In particular, it is preferable to use M _y O _z (M represents an element that does not cause a valence change, and y and z represent a positive number) as the inorganic oxide. This is because the metal causing valence change is that it has not a little catalytic activity to generate a H ₂ gas from the resin is based on the present inventor has knowledge. Specifically, metal oxides that cause valence changes tend to have oxygen vacancies, and the outermost surface of the oxide has dangling bonds (bonding bonds), so that it is locally metallized. The present inventors have found that the C—H bond in the resin is easily dissociated due to the above. Therefore, dissociation of C—H bonds in the resin is effectively prevented by using an oxide of an element that does not cause a valence change as the inorganic oxide.

An element that does not cause a valence change is an element having a single oxidation number, and is preferably a metal or metalloid element. Specific examples of such elements include Al, Si, Ba, Ca, Cd, Er, Ga, Gd, Hf, Ho, In, La, Lu, Mg, Rb, Sn, Sr, Y, Zn, and Zr. Is mentioned. Of these, from the viewpoint of safety and economy, it is preferable to use oxides of Al and Si. Specifically, it is preferable to use SiO ₂ or Al ₂ O ₃ . Incidentally, the above M _y O _z may be used in combination alone one or two or more. Furthermore, at least one of said M _y O _z, may be used in combination with at least one inorganic oxide other than it.

In particular, as the inorganic oxide, it is preferable to use at least one selected from a composite oxide of M _y O _z and the element M and cerium oxide, and in particular, a composite oxide of SiO ₂ , Al ₂ O ₃ , Si and Ce. In addition, it is preferable to use at least one selected from a composite oxide of Al and Ce.

In the oxygen scavenger of the present invention, from the viewpoint of preventing the dissociation of C—H bonds in the resin and the prevention of drawing of oxygen atoms in the resin, the inorganic oxide is added to 100 parts by mass of cerium oxide having oxygen deficiency. The amount is preferably 3 to 50 parts by mass, more preferably 5 to 30 parts by mass, and even more preferably 7.5 to 15 parts by mass.

From the same viewpoint as described above, in the oxygen scavenger of the present invention, the particle diameter of the cerium oxide particles having oxygen deficiency coated with the inorganic oxide is not particularly limited, and those having various particle diameters can be used. It is. From the viewpoint of ease of film formation and high gas barrier properties, the average particle diameter D ₅₀ is preferably 0.05 μm or more and 50 μm or less, more preferably 0.1 μm or more and 40 μm or less, and more preferably 0.5 μm. More preferably, it is 25 μm or less.

The cerium oxide particles before being coated with the inorganic oxide preferably have an average particle diameter D ₅₀ of 0.05 μm or more and 50 μm or less, more preferably 0.1 μm or more and 40 μm or less. More preferably, it is 5 μm or more and 30 μm or less. The particle diameter of the inorganic oxide particles is the assumption that less than the average particle diameter D ₅₀ of the cerium oxide, from the efficiency of the coating, preferably at 2nm or more 10μm or less is 2nm or more 5μm or less Is more preferably 2 nm or more and 1 μm or less. The average particle diameter D ₅₀ of the particles by setting like this, it is possible to prevent the dissociation of the C-H bonds in the resin effectively, also to prevent withdrawal of oxygen atoms in the resin effectively be able to.

The above particle sizes are measured using a particle size distribution measuring apparatus using a laser diffraction / scattering method if the particle size is 0.1 μm or more, and the dynamic light scattering method (photon) if the particle size is less than 0.1 μm. It is measured using a particle size distribution measuring apparatus using a correlation method.

The cerium oxide particles having oxygen vacancies coated with an inorganic oxide are preferably produced by the following method. First, cerium oxide is produced by firing cerium-containing salts or hydrates thereof (hereinafter collectively referred to simply as “cerium-containing salts”). This cerium oxide has a fluorite-type structure represented by CeO ₂ , and contains cerium and oxygen in a substantially stoichiometric ratio. Therefore, this cerium oxide has no oxygen deficiency. The term “substantially” is used to allow the presence of trace amounts of inevitable impurities. The firing of the cerium-containing salt is preferably performed in the atmosphere. Firing is possible even in an oxidizing atmosphere without being in the air, but in consideration of production on an industrial scale, firing in the air is preferable.

In order to obtain the target cerium oxide having reversible oxygen deficiency, the firing temperature is preferably in the range of 500 ° C. to 1400 ° C., more preferably 600 ° C. to 1300 ° C., and the firing time is preferably Is in the range of 1 hour to 20 hours, more preferably 1 hour to 5 hours. By setting the calcination temperature within this range and setting the calcination time within this range, the calcination proceeds sufficiently and the oxidation of the cerium-containing salt proceeds successfully.

The cerium-containing salt is not particularly limited as long as it produces cerium oxide by firing. For example, cerium carbonate hydrate (hexahydrate, octahydrate, etc.), cerium nitrate, ammonium cerium nitrate, cerium sulfate, cerium sulfate, cerium hydroxide, cerium oxalate, cerium acetylacetonate, cerium trifluoromethanesulfonate, etc. Can be used. Of these, cerium carbonate and cerium hydroxide are preferably used.

Calcination of the cerium-containing salt can be performed, for example, while circulating air in a heating furnace in which the cerium-containing salt is allowed to stand. Alternatively, firing can be performed using a rotary kiln furnace or the like while flowing air under a state where the cerium-containing salt is fluidized (rolled). In any case, the cerium-containing salt to be fired is preferably adjusted in particle size using a pulverizer such as a ball mill as a pretreatment for firing.

The cerium oxide particles having no oxygen vacancies obtained as described above have a particle size D ₅₀ (volume cumulative particle size at a cumulative volume of 50 vol% by laser diffraction scattering type particle size distribution measurement method) of 0. The thickness is from 0.5 μm to 50 μm, preferably from 0.1 μm to 40 μm, and more preferably from 0.5 μm to 30 μm.

The inorganic oxide particles are adhered to the surface of the cerium oxide particles having no oxygen vacancies thus obtained. There is no restriction | limiting in particular in the attachment method, A various method is employable. As an example, a method of preparing a dispersion by stirring and mixing cerium oxide particles having no oxygen deficiency, inorganic oxide particles, and a medium, and subjecting the dispersion to spray drying treatment (spray drying treatment). Can be adopted. Alternatively, the inorganic oxide particles can be attached to the surface of the cerium oxide particles having no oxygen vacancies by simply drying the dispersion liquid and then drying it. In the composite particles thus obtained, the binding force between the cerium oxide particles and the inorganic oxide particles may not be sufficient. In such a case, the composite particles are preferably subjected to a firing step to sinter the cerium oxide particles and the inorganic oxide particles. In general, the firing is preferably performed in the air. Firing is possible even in an oxidizing atmosphere without being in the air, but in consideration of production on an industrial scale, firing in the air is preferable. The firing temperature is preferably in the range of 200 ° C. to 1400 ° C., more preferably in the range of 500 ° C. to 1200 ° C., and the firing time is preferably in the range of 1 hour to 20 hours, more preferably in the range of 2 hours to 5 hours. Is adopted. By setting the firing temperature within this range and setting the firing time within this range, sintering of the cerium oxide particles and the inorganic oxide particles proceeds sufficiently, and the bonding strength between the two is improved.

Next, the cerium oxide particles having the inorganic oxide particles attached thereto are subjected to a reduction firing step. As the reducing atmosphere, a hydrogen-containing atmosphere having a hydrogen concentration of preferably at least the lower explosion limit, more preferably at least 20% by volume is used. Of course, the hydrogen concentration may be 100% by volume. The temperature is 700 ° C. or higher and 1100 ° C. or lower, more preferably 800 ° C. or higher and 1050 ° C. or lower, more preferably 800 ° C. or higher and 1000 ° C. or lower. The time is preferably 1 minute or longer and 5 hours or shorter, more preferably 5 minutes. A range of 3 hours or less is employed. By adopting these conditions, oxygen is extracted from cerium oxide having no oxygen deficiency, and fluorite-type cerium oxide having reversible oxygen deficiency is obtained. Even when the entire surface of the cerium oxide particles is uniformly covered with an inorganic oxide, the coating made of the inorganic oxide has oxygen permeability. A fluorite-type cerium oxide having defects and capable of absorbing oxygen is obtained. The rate of temperature rise is preferably 0.5 ° C./min to 50 ° C./min, particularly 1 ° C./min to 30 ° C./min. The reducing atmosphere is generally atmospheric pressure (atmospheric pressure), but instead of this, pressurizing conditions or depressurizing conditions may be used. By appropriately controlling this reduction condition, the value of _x in CeO _x can be controlled.

The reduction treatment of cerium oxide having no oxygen deficiency can be performed, for example, while circulating a reducing gas in a heating furnace in which the cerium oxide is placed. Alternatively, the reduction can be performed using a rotary kiln furnace or the like while circulating the reducing gas in a state in which cerium oxide having no oxygen deficiency flows (rolls). In any case, when an atmosphere of 100% hydrogen is used as the reducing atmosphere, the flow rate is preferably 1 to 500 SCCM per gram of cerium oxide.

Particles of cerium oxide having oxygen vacancies (hereinafter, this cerium oxide is also referred to as “inorganic oxide-coated cerium oxide”), the surfaces of which are thus obtained, are covered with inorganic oxide particles. Can be used as an oxygen scavenger as it is. Specifically, it can be used as a deoxygenated package in which inorganic oxide-coated cerium oxide particles are encapsulated in a package having air permeability resistance. In this case, the inorganic oxide-coated cerium oxide can be encapsulated in the package in the form of a powder or in the form of a compact such as a tablet or flake obtained by pressurizing the powder. Alternatively, in the present invention, inorganic oxide-coated cerium oxide particles can be used in the form of a resin composition formed by mixing with various resins. Specifically, inorganic oxide-coated cerium oxide particles can be kneaded into a resin having oxygen permeability so as to obtain a deoxygenated resin composition. The deoxygenated resin composition may be used as a deoxygenated package by enclosing it in the package having air permeability resistance. As the resin, either a thermoplastic resin or a thermosetting resin may be used. The air resistance is measured according to JIS P8117 and is the time required for 100 mL of air to finish permeating through an area of 0.000642 m ² with a pressure difference of 1.23 kPa. Having air permeability resistance means that the time measured by the above method is 100,000 seconds or less.

The oxygen-absorbing package comprising the inorganic oxide-coated cerium oxide particles and the oxygen-absorbing package comprising the oxygen-absorbing resin composition may further include a desiccant or a deodorizing agent. . There is no restriction | limiting in particular in the shape of a package, A well-known shape can be selected suitably and can be used. For example, four-side seal bag, three-side seal bag, two-side seal bag, back-attached (joint palm) bag, gusset bag, tetra-pack package, pillow package, PTP package, blister package, bottle, cup, lid material, cap Various shapes of packages such as materials can be used.

FIG. 1 shows a schematic sectional view of a packaging container 10 for PTP or blister pack as an example of a package. The packaging container 10 for PTP or blister pack includes a film 11 for PTP or blister pack formed by laminating an oxygen absorption layer 12 and a gas barrier layer 13 and a base material 14 laminated on the oxygen absorption layer 12 side of this film. Have. The packaging container 10 is formed of PTP or blister pack film 11 and the base material 14 such as PTP molding so as to form a space for storing the content 15 defined by the oxygen absorbing layer 12 and the base material 14. It is manufactured by molding using a molding method. As the content 15, inorganic oxide-coated cerium oxide or a resin composition containing the same is used. The thickness of each layer is preferably 10 μm or more and 50 μm or less.

When the deoxygenated resin composition includes a thermoplastic resin, examples of the thermoplastic resin include linear low density polyethylene (LLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), and high density polyethylene. Polyethylene resins such as (HDPE) and ethylene-vinyl acetate copolymer (EVA) can be used. In addition, ordinary homopolymer polypropylene resins and copolymer polypropylene resins such as random copolymer polypropylene and block copolymer polypropylene can be used as the thermoplastic resin. From the viewpoint of ease of molding, it is advantageous to use polystyrene.

Thermoplastic resins can control the rate of deactivation of oxygen absorption capacity until the inorganic oxide-coated cerium oxide is packaged or incorporated into electronic devices by controlling its own oxygen permeability. . Specifically, polycarbonate (PC), ethylene-vinyl alcohol copolymer (EVOH), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyacetic acid are resins having lower oxygen permeability than polyethylene and polypropylene. Vinyl (PVAc), polyvinyl chloride (PVC), polyamides (nylon 6, nylon 11, nylon 12, nylon 66, nylon 610, nylon 6T, nylon 6I, nylon 9T, nylon M5T, nylon 612, nylon MXD), poly Use of vinylidene chloride (PVDC), polyvinylidene fluoride (PVDF), polyvinyl alcohol (PVA), polyacrylonitrile (PAN), polymethyl methacrylate resin (PMMA) to control the rate of deactivation of oxygen absorption capacity Possible it is.

On the other hand, when oxygen absorption is desired to be performed quickly, polydimethylsiloxane or polybutadiene which is a resin having high oxygen permeability can be used as the thermoplastic resin.

The thermoplastic resin used in the present invention is melt flow rate (MFR, JISK7210: 1999 compliant with Method A, at a measurement temperature of 190 ° C. and a load of 2.16 kg from the viewpoint of facilitating processing into a film or sheet. Measured) is preferably 10 g / 10 min or more and 50 g / 10 min or less. Moreover, when using for injection molding, the thermoplastic resin whose melt flow rate is 50.0 g / 10min or more is preferable. When used for extrusion molding, a thermoplastic resin having a melt flow rate of 10 g / 10 min or less is preferred.

When a thermosetting resin is used as the resin contained in the deoxygenated resin composition, it is advantageous in that the deoxygenated resin composition can cope with a complicated shape and the sealing property is improved particularly when the deoxygenated resin composition is incorporated into an electronic device. . Such thermosetting resins include phenolic resin (PF), epoxy resin (EP), melamine resin (MF), urea resin (urea resin, UF), unsaturated polyester resin (UP), alkyd resin, polyurethane ( PUR) and thermosetting polyimide (PI). In order to cure the thermosetting resin, in general, a compound having an oxygen-containing functional group such as a hydroxyl group is often used. Therefore, the conventional cerium oxide-based oxygen scavenger could not be used. Since the oxygen scavenger of the present invention effectively prevents the extraction of oxygen atoms, there is no adverse effect on the combined use with the thermosetting resin.

For example, when a thermoplastic resin is included, the deoxygenated resin composition is used in the form of strands or pellets obtained by finely cutting the strands, and is a raw material for various resin molded products. The resin composition is used in the form of various resin moldings molded from the pellets, for example, in the form of a deoxygenation functional film having a deoxygenation layer, or in the form of a deoxygenation functional tray or cup. Specifically, the shape of pellets, strands, films, or cups for organic EL lighting, organic EL displays, dye-sensitized solar cells, organic thin film solar cells, and electrochromic elements that are vulnerable to oxygen An electronic device can be obtained by disposing a deoxygenated resin composition containing a thermoplastic resin in a sheet shape between layers. On the other hand, when the deoxygenated resin composition contains, for example, a thermosetting resin, it can be molded to have an arbitrary shape according to the usage scene. For example, when the deoxygenated resin composition is an epoxy resin composition, it can be used in the form of a sealing material for electronic devices such as semiconductor elements.

In the above-described deoxygenated resin composition, the mixing ratio of the deoxidizer, that is, inorganic oxide-coated cerium oxide, and the thermoplastic resin or thermosetting resin can be selected from a wide range. For example, the compounding ratio of the inorganic oxide-coated cerium oxide and the thermoplastic resin or thermosetting resin is expressed by mass ratio from the viewpoint of maintaining the strength and moldability of the deoxygenated resin composition. The former: the latter = 10: It is preferably 90 to 80:20, more preferably 20:80 to 75:25, and still more preferably 30:70 to 75:25. When the oxygen-absorbing resin composition is used in a state where the proportion of the inorganic oxide-coated cerium oxide is large, for example, 50% by mass or more and 90% by mass or less with respect to the whole, MFR suitable for film molding is used as the resin. It is advantageous to select what has.

The oxygen scavenger of the present invention can be used in the form of a oxygen scavenging film having a oxygen scavenging layer containing the oxygen scavenger. This deoxygenated film can be obtained, for example, by molding the deoxygenated resin composition into a film. Further, the oxygen scavenger of the present invention has a multilayer structure in which a gas barrier layer having a gas barrier property is provided on one surface side of the oxygen scavenging layer, and an oxygen permeable layer having oxygen permeability is provided on the other surface side of the oxygen scavenging layer. It can also be used in the form of a deoxygenated film. In the present invention, even when the oxygen scavenger is used in the form of a film having such a multilayer structure, delamination due to generation of H ₂ gas is effectively prevented.

In the deoxygenated film having the multilayer structure, an adhesive layer for adhering both layers may be provided between the gas barrier layer and the oxygen permeable layer as necessary. In addition to or instead of this, a heat sealing adhesive layer may be provided on the outermost surface on the other surface side.

As said gas barrier layer, metal foil, such as aluminum foil and copper foil, can be used, for example. Alternatively, a gas barrier film such as ethylene-vinyl alcohol copolymer (EVOH) or polyimide can be used. This gas barrier film may be coated with polysilazane or colloidal silica. Alternatively, SiO ₂ or ZrO ₂ may be deposited on the gas barrier film.

As the adhesive layer for heat sealing, for example, polyolefin resin (LDPE, LLDPE, PP, EVA, etc.) can be used. Alternatively, an ethylene-vinyl alcohol copolymer comprising an island-and-sea structure resin composition containing EVOH and maleic anhydride-modified polyolefin resin, and forming a sea structure that is relatively continuous. A structure in which an island structure is formed can be used.

FIG. 2 shows another embodiment of a deoxygenated film having a multilayer structure. The multilayered oxygen-absorbing film 20 has thermoplastic resin layers 22a and 22b arranged on each surface of an oxygen-absorbing layer 21 containing an oxygen-absorbing agent, and a gas barrier layer 23 and a substrate outside the one thermoplastic resin layer 22a. The material film 24 has a structure laminated in this order. By laminating the gas barrier layer 23 and / or the base film 24, intrusion of gas such as oxygen can be blocked more reliably, and the strength of the deoxidized film 20 having a multilayer structure can be increased.

FIG. 3 shows still another embodiment of a deoxygenated film having a multilayer structure. The multilayered oxygen scavenging film 30 includes a oxygen scavenging layer 31 having a main oxygen scavenging layer 31a and a sub oxygen scavenging layer 31b that is disposed on each surface and assists the oxygen scavenging. A gas barrier layer 32 for preventing water vapor from entering from the outside air is disposed as an outermost layer on the outer side of one sub-deoxygenation layer 31b. The main oxygen scavenging layer 31a and / or the sub oxygen scavenging layer 31b can contain inorganic oxide-coated cerium oxide.

In the present invention, when a deoxygenated resin composition containing inorganic oxide-coated cerium oxide and a resin is used, for example, in the form of a film, the film is incorporated into an electronic device, for example, and used as an electronic device provided with the film. Can do. In this electronic device, there is a case where a large amount of heat is generated by the operation, but according to the present invention, even in such a case, dissociation of the C—H bond in the resin is effectively prevented. .

Various additives can be blended with the resin composition containing the inorganic oxide-coated cerium oxide and the resin for the purpose of enhancing various properties of the resin composition. For example, oxygen scavengers other than inorganic oxide-coated cerium oxide, desiccants, and acetic acid absorbents can be used. Examples of the oxygen scavenger other than the inorganic oxide-coated cerium oxide include a mixture of gallic acid and a transition metal compound, and a mixture containing a carbonate-based alkali compound such as potassium carbonate, sodium carbonate, calcium carbonate in the mixture. It is done. Examples of the desiccant include a deliquescent inorganic salt, a deliquescent organic compound, a superabsorbent resin, silica gel, and synthetic zeolite. As the acetic acid absorbent, for example, magnesium oxide, and magnesium oxide selected from ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic monomer copolymer, and ethylene-α-olefin copolymer that are compatible with acetic acid And those dispersed in a binder.

The oxygen scavenger of the present invention can be used as a oxygen scavenging adhesive by mixing it with an adhesive composition, for example, in addition to the resin mixing. Furthermore, the oxygen scavenger of the present invention can be mixed with an ink composition and used as an oxygen scavenging ink.

As described above, the oxygen scavenger of the present invention can be mixed with various substances and used as various compositions. Whether or not the composition contains the inorganic oxide-coated cerium oxide constituting the oxygen scavenger of the present invention is determined by, for example, thermally decomposing the composition to remove organic components and elemental mapping of the residue by EDX. This can be determined by surface analysis using XPS. Alternatively, it can also be determined by structural analysis of the residue by XRD. In the case of a substance whose structure is changed by thermal decomposition, the inorganic oxide is a single element oxide by directly analyzing the structure by XRD measurement for the resin composition of the resin and the oxygen scavenger. It is possible to identify whether it is a composite oxide of two or more elements, or a composite oxide formed by a reaction between cerium oxide itself and an element covering it.

In addition to having the function of removing oxygen in the atmosphere, the oxygen scavenger of the present invention also has a function of removing bad odors in the atmosphere. That is, the oxygen scavenger of the present invention also has a function as a deodorizer. The malodorous substances to be removed include a wide range, and examples include oxygen-containing compounds, nitrogen-containing compounds, sulfur-containing compounds, and hydrocarbons.
Examples of the oxygen-containing compound include aldehydes such as acetaldehyde, propionaldehyde, n-butyraldehyde and i-butyraldehyde, alcohols such as i-butanol, esters such as ethyl acetate, and ketones such as methyl isobutyl ketone and diacetyl. And organic carboxylic acids such as propionic acid, n-butyric acid, n-valeric acid and i-valeric acid.
Examples of the nitrogen-containing compound include amines such as ammonia and trimethylamine.
Examples of the sulfur-containing compound include methyl mercaptan, hydrogen sulfide, methyl sulfide, and methyl disulfide.
Examples of the hydrocarbon include aromatics such as toluene, styrene and xylene.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such examples. Unless otherwise specified, “%” means “mass%”.

[Example 1]
(1) Synthesis of cerium oxide having no oxygen deficiency 100 g of cerium carbonate was allowed to stand in a heating furnace and heated and baked while circulating air. Heating was started from room temperature, heated at a rate of temperature increase of 10 ° C./min, and after reaching 500 ° C., this temperature was maintained for 20 hours. Then, it naturally left to cool. The air flow rate was 1000 SCCM. Thus, a porous body of cerium oxide having no oxygen deficiency was obtained. Measurement by XRD confirmed that this cerium oxide was represented by CeO ₂ and had a fluorite-type crystal structure. This cerium oxide was pulverized by a ball mill. Particle size _{D 50} of the cerium oxide was 20 [mu] m.

(2) Adhesion of inorganic oxide Colloidal silica having a nominal particle size of 10 to 15 nm was used as the inorganic oxide. Colloidal silica sol “Snowtex” model ST-O) manufactured by Nissan Chemical Industries, Ltd. is weighed to 7.5 parts in terms of SiO ₂ with respect to 100 parts of cerium oxide powder. 1 hour after adjusting pure water and mixing cerium oxide powder, SNOWTEX, and pure water so that the total of the SiO ₂ components, that is, the mass of solids is 40 parts with respect to 100 parts of the mixed solution Stir above. While stirring so that the solid content of the dispersion did not cause precipitation, spray drying treatment was performed with a spray dryer (model GB210) manufactured by Yamato Scientific Co., Ltd. At this time, the hot air was controlled at an inlet temperature of 170 ° C., and the air volume was set to about 0.75 m ³ / min. The spraying method of the spray dryer employs a two-fluid nozzle system, and the dispersion is sent to the nozzle at a throughput of 10 mL / min as the first fluid, and compressed air is used as the second fluid at a pressure of 0.2 MPa. Sent to the nozzle. The powder after spray drying was collected and baked at 1000 ° C. for 2 hours to obtain a cerium oxide powder treated with SiO ₂ .

(3) Synthesis of cerium oxide having oxygen deficiency The cerium oxide (50 g) obtained in the previous item (2) was left in a heating furnace, and reduced by heating while circulating 100% hydrogen gas. Heating was started from room temperature, heated at a rate of temperature increase of 10 ° C./min, and after reaching 1000 ° C., this temperature was maintained for 1 hour. Then, it naturally left to cool. The circulation amount of hydrogen gas was 1000 SCCM. In this way, cerium oxide having reversible oxygen deficiency was obtained. As a result of measurement by XRD, it was confirmed that this cerium oxide has a fluorite-type crystal structure. Particle size _{D 50} in the cerium oxide was 20 [mu] m. As a result of elemental analysis, this cerium oxide was represented by CeO _1.75 . The result of element mapping of the obtained inorganic oxide-coated cerium oxide is shown in FIG. The observation magnification of the figure is 6000 times. In the figure, “Grey” indicates the SEM image of the particle, “SiK” indicates the presence mapping result of the Si element, and “CeL” indicates the presence mapping result of the Ce element. . The element mapping used was an FE-SEM “JSM-7001F” manufactured by JEOL Ltd. (JEOL) equipped with EDX “INCA PentaFETx3” as an EDX detector. As is apparent from the results shown in the figure, it can be seen that SiO ₂ uniformly covers the surface of the cerium oxide particles when viewed macroscopically.

(4) Production of resin composition A kneader system was used for production of the resin composition. This kneader system is composed of two types of quantitative feeders (for cerium oxide and resin), kneader “Asahi Tekko Co., Ltd., single-screw kneading extruder (Miracle KCK model L)”, tank, winding in order from upstream to downstream. A take-up machine, a cutter, and a collection container are arranged. All apparatuses have a structure capable of circulating and purging inert gas including nitrogen gas.
The kneading machine is composed of a feed part for feeding the input raw material into the kneading machine, a kneading part for applying shear stress to knead the raw material, a vent part for defoaming, a metering part for discharging with a screw, and a die part having a discharge port.

The operation described below was performed using the above system.
That is, first, nitrogen gas was circulated through all apparatuses until the oxygen concentration reached 0%. The inorganic oxide-coated cerium oxide obtained in the previous item (3) and low-density polyethylene (Excellen FX402, MFR 8.0 g / 10 min) manufactured by Sumitomo Chemical Co., Ltd. are filled into separate feeders, and the inorganic oxide-coated cerium oxide 60 The low-density polyethylene resin was quantitatively charged into the kneader so as to be 3.0 kg / h and 2.0 kg / h, respectively, at a ratio of 40 parts to the part. Next, the feed part of the kneading machine is heated to 50 ° C., the kneading part is heated to 125 ° C., the venting part is heated to 130 ° C., the metering part is heated to 135 ° C., and the die part is heated to 140 ° C. did. The hole diameter of the die part was 5 mmφ. The resin composition discharged from the die part was passed through a cooling water tank cooled to 10 ° C. by a chiller, and then passed through a winder and a cutter. By adjusting the winding speed of the winder and the rotation speed of the cutter blade, a master batch obtained by processing the resin composition into a cylindrical shape having a diameter of about 6 mm and a length of about 6 mm was obtained, and this was collected in a collection container. .

(5) Evaluation About the obtained master batch, the generation amount of hydrogen gas and the oxygen absorption amount were measured. The results are shown in Table 1 below. The measurement was performed by the following method.

[Hydrogen gas generation]
In a glove box having an inert gas atmosphere, 50 g of a master batch was put into an A4 size aluminum laminated bag equipped with a sampling cock of “Tedlar Bag” manufactured by AS ONE Co., Ltd., and the opening was sealed with a heat sealer. Next, 1000 mL of nitrogen gas was sealed in the bag through the sampling cock. The bag was taken out of the glove box, allowed to stand in a high temperature and humidity chamber “SH-222” manufactured by Espec, and stored at 85 ° C. for 24 hours. Thereafter, 1000 mL of dry air was added to the bag, and immediately, the concentration of hydrogen gas was measured using a Kitagawa-type hydrogen detector tube “137U” manufactured by Komyo Chemical Co., Ltd. For reference, in some tests, the hydrogen gas concentration was measured again after 96 hours. The reason why the dry air is added is due to the principle that the detection tube causes coloration by the reaction of H ₂ + O ₂ → H ₂ O.

[Oxygen absorption]
In a glove box having an inert gas atmosphere, 2 g of inorganic oxide-coated cerium oxide or cerium oxide having reversible oxygen vacancies was collected and included in a package having an air resistance of 100,000 seconds. Separately from this, a package having the same material and the same size and the same air resistance is prepared without encapsulating inorganic oxide-coated cerium oxide or cerium oxide having reversible oxygen deficiency. A package containing inorganic oxide-coated cerium oxide or cerium oxide having reversible oxygen vacancies is exposed to the atmosphere (25 ° C, 1 atm), and after 24 hours the mass is measured with a precision electronic balance (4 digits or more after the decimal point) Was measured. In addition, in order to correct the increase in mass due to moisture adsorbed on the package itself, the mass of the package that does not contain inorganic oxide-coated cerium oxide or cerium oxide having reversible oxygen deficiency is also measured, The mass was reduced from the mass of the package containing the inorganic oxide-coated cerium oxide or the cerium oxide having reversible oxygen deficiency. The amount of oxygen absorbed was calculated using the gas equation of state, where the increase in measured weight was the oxygen weight.

[Examples 2 to 4 and Comparative Example 1]
The amount of colloidal silica used in step (2) of Example 1 was changed so that the amount of SiO ₂ with respect to 100 parts of cerium oxide was as shown in Table 1. Except this, it carried out similarly to Example 1, and obtained the masterbatch. The same measurement as in Example 1 was performed on the obtained master batch. The results are shown in Table 1.

As is clear from the results shown in Table 1, it can be seen that the generation of hydrogen gas is suppressed in the master batch of each example compared to the master batch of the comparative example. It can be seen that the cerium oxide used in each Example and Comparative Example 1 absorbs oxygen.

Example 5
In this example, colloidal silica was attached to the surface of the cerium oxide particles by another method instead of the spray drying process employed in the step (2) of Example 1. The details are as follows.
Colloidal silica sol “Snowtex” (model ST-O) manufactured by Nissan Chemical Industries, Ltd. is 7.5 parts in terms of SiO ₂ with respect to 100 parts of the cerium oxide powder obtained in step (1) of Example 1. Weighed as follows. Next, the colloidal silica sol was diluted with pure water until the liquid absorption amount of the cerium oxide powder was reached. The liquid absorption amount is an amount until the supernatant starts to appear after the colloidal silica sol pure water diluted solution is absorbed by the cerium oxide powder.
The colloidal silica sol diluted to the liquid absorption amount was poured into the cerium oxide powder transferred into the container while stirring with a drug vessel, and after that, the solid was obtained by drying with a box type dryer at 120 ° C. for 12 hours. . This solid was pulverized with a “multi-mill (RD1-15 grinder type)” manufactured by Glow Engineering Co., Ltd. The crushing conditions were a gap between grinders of 50 μm and a rotation speed of 1700 rpm.
Thereafter, a master batch was obtained in the same manner as in Example 1. The same measurement as in Example 1 was performed on the obtained master batch. The results are shown in Table 2. In Table 2, the measurement results of Example 1 and Comparative Example 1 are also shown for comparison.
Moreover, the result of the element mapping of the obtained inorganic oxide covering cerium oxide is shown in FIG. Element mapping was performed in the same manner as in Example 1. The observation magnification is 6000 times. In the figure, “Grey” indicates the SEM image of the particle, “SiK” indicates the presence mapping result of the Si element, and “CeL” indicates the presence mapping result of the Ce element.

As is clear from the results shown in Table 2, it can be seen that the method of depositing colloidal silica does not affect the suppression of hydrogen gas generation. That is, it can be seen that the effect of suppressing the generation of hydrogen gas is exhibited no matter what method is used to attach colloidal silica.
Further, as is apparent from the results shown in FIG. 5, it can be seen that SiO ₂ uniformly coats the surface of the cerium oxide particles macroscopically.

Example 6
In this example, instead of the colloidal silica used in Example 1, alumina having a nominal particle size of 7 to 15 nm was used as the inorganic oxide.
Colloidal alumina sol (model AS-200) manufactured by Nissan Chemical Industries, Ltd. was weighed to 7.5 parts in terms of Al ₂ O ₃ with respect to 100 parts of cerium oxide powder. Next, the colloidal alumina sol was diluted with pure water until the liquid absorption amount of the cerium oxide powder was reached.
The colloidal alumina sol diluted to the liquid absorption amount was poured into the cerium oxide powder transferred into the container while stirring with a drug vessel, and then dried with a box-type dryer at 120 ° C. for 12 hours to obtain a solid. . This solid was pulverized with a “multi-mill (RD1-15 grinder type)” manufactured by Glow Engineering Co., Ltd. The crushing conditions were a gap between grinders of 50 μm and a rotation speed of 1700 rpm.
Thereafter, a master batch was obtained in the same manner as in Example 1. The same measurement as in Example 1 was performed on the obtained master batch. The results are shown in Table 3.

Example 7
In this example, instead of directly attaching alumina to the surface of the cerium oxide particles in Example 6, boehmite, which is a precursor of alumina, was attached and converted to alumina.
Boehmite sol (model AS-520) manufactured by Nissan Chemical Industries, Ltd. was weighed to 7.5 parts in terms of Al ₂ O ₃ with respect to 100 parts of cerium oxide powder. Except this, it carried out similarly to Example 6, and obtained the masterbatch. The same measurement as in Example 1 was performed on the obtained master batch. The results are shown in Table 3.

As is clear from the results shown in Table 3, it can be seen that even when alumina is used as the inorganic oxide, the effect of suppressing the generation of hydrogen gas is exhibited.

[Examples 8 to 11]
The amount of colloidal alumina used in Example 6 was changed, and the amount of Al ₂ O ₃ relative to 100 parts of cerium oxide was as shown in Table 4. Except this, it carried out similarly to Example 6, and obtained the masterbatch. The same measurement as in Example 1 was performed on the obtained master batch. The results are shown in Table 4. In Table 4, the measurement results of Example 6 and Comparative Example 1 are also shown for comparison.

As is clear from the results shown in Table 4, it can be seen that the generation of hydrogen gas is suppressed in the master batch of each example compared to the master batch of the comparative example.

Examples 12 and 13
In this example, the particle size of the cerium oxide particles used in Example 5 was changed.
In Example 12, the cerium oxide particles used in Example 5 were pulverized using a pin mill (Coloplex 160Z) manufactured by Hosokawa Micron Corporation through two passes at a rotation frequency of 30 Hz. Particle size D ₅₀ after grinding were as shown in Table 5.
In Example 13, the cerium oxide particles used in Example 5 were pulverized through one pass at a rotational frequency of 20 Hz using a pin mill (Coroplex 160Z) manufactured by Hosokawa Micron Corporation. Particle size D ₅₀ after grinding were as shown in Table 5.
Except this, it carried out similarly to Example 5, and obtained the masterbatch. The same measurement as in Example 1 was performed on the obtained master batch. The results are shown in Table 5. In Table 5, the measurement results of Example 5 and Comparative Example 1 are also shown for comparison.

[Comparative Examples 2 and 3]
In this comparative example, the particle size of the cerium oxide particles used in Example 1 is changed.
In Comparative Example 2, the cerium oxide particles used in Comparative Example 1 were pulverized through two passes at a rotation frequency of 30 Hz using a pin mill (Coloplex 160Z) manufactured by Hosokawa Micron Corporation. Particle size D ₅₀ after grinding were as shown in Table 5.
In Comparative Example 3, the cerium oxide particles used in Comparative Example 1 were pulverized through one pass at a rotational frequency of 20 Hz using a pin mill (Coroplex 160Z) manufactured by Hosokawa Micron Corporation. Particle size D ₅₀ after grinding were as shown in Table 5.
Except this, it carried out similarly to the comparative example 1, and obtained the masterbatch. The same measurement as in Example 1 was performed on the obtained master batch. The results are shown in Table 5.

As is apparent from the results shown in Table 5, even when the particle size of the cerium oxide particles was changed, the master batch of each example was less likely to generate hydrogen gas than the master batch of the comparative example. You can see that

Examples 14 and 15
In this example, the compounding ratio between the inorganic oxide-coated cerium oxide and the low-density polyethylene was changed in Example 5 to the values shown in Table 6. Except this, it carried out similarly to Example 5, and obtained the masterbatch. The same measurement as in Example 1 was performed on the obtained master batch. The results are shown in Table 6. In Table 6, the measurement results of Example 5 and Comparative Example 1 are also shown for comparison.

[Comparative Examples 4 and 5]
This comparative example changes the compounding ratio of inorganic oxide-coated cerium oxide and low-density polyethylene in Comparative Example 1 to the values shown in Table 6. Except this, it carried out similarly to the comparative example 1, and obtained the masterbatch. The same measurement as in Example 1 was performed on the obtained master batch. The results are shown in Table 6.

As is clear from the results shown in Table 6, even when the compounding ratio of the inorganic oxide-coated cerium oxide and the low density polyethylene was changed in a wide range, the master batch of each example was changed to the master batch of the comparative example. In comparison, it can be seen that the generation of hydrogen gas is suppressed.

[Examples 16 to 18]
In this example, instead of the low density polyethylene which is the resin used in Example 5, the resin shown in Table 7 was used. Except this, it carried out similarly to Example 5, and obtained the masterbatch. The same measurement as in Example 1 was performed on the obtained master batch. The results are shown in Table 7. Table 7 also shows the measurement results of Example 5 and Comparative Example 1 for comparison.

[Comparative Examples 6 to 8]
This comparative example is an example in which the resins shown in Table 7 were used in place of the low density polyethylene which is the resin used in Comparative Example 1. Except this, it carried out similarly to the comparative example 1, and obtained the masterbatch. The same measurement as in Example 1 was performed on the obtained master batch. The results are shown in Table 7.

As is clear from the results shown in Table 7, even when the type of resin is variously changed, the generation of hydrogen gas is suppressed in the master batch of each example compared to the master batch of the comparative example. I understand.

Examples 19 and 20
In this example, instead of the low density polyethylene which is the resin used in Example 5, the resins shown in Table 8 were used. The resin shown in the table is an oxygen-containing resin that has not been used together with cerium oxide having oxygen deficiency. 50 parts each of this resin and cerium oxide (CeO _1.75 ) having oxygen deficiency obtained by coating 7.5% of SiO ₂ obtained in Example 1 (3) under a nitrogen atmosphere in a glove box. The sample was weighed and manually kneaded on a hot plate (set temperature: 250 ° C.), and the presence of smoke and gas was visually observed. The results are shown in Table 8. When kneading cerium oxide having oxygen deficiency with a resin, in this test, from the viewpoint of safety, in a nitrogen atmosphere in a glove box without using a kneading extruder as in Example 1 (4). Then, a method of kneading on a small scale and visually confirming superiority or inferiority was adopted.

[Comparative Examples 9 and 10]
In this comparative example, instead of the SiO ₂ surface-coated cerium oxide used in Examples 19 and 20, cerium oxide (CeO _1.75 ) having oxygen deficiency without any surface coating was used. The obtained kneaded material was observed in the same manner as in Examples 19 and 20. The results are shown in Table 8.

As is clear from the results shown in Table 8, it can be seen that even in the case of using an oxygen-containing resin as the resin, the master batch of each example has suppressed the generation of smoke and gas. In contrast, in the master batches of each comparative example, cerium oxide having oxygen deficiency decomposes the resin by extracting oxygen atoms from the oxygen-containing resin, resulting in smoke generation and gas generation. Observed.

Example 21
In this example, an epoxy resin which is a thermosetting resin was used instead of the low density polyethylene used in Example 1. The epoxy resin was cured using the components shown in Table 9. The mixing of the inorganic oxide-coated cerium oxide and the epoxy resin was performed according to the following operation. Under a nitrogen atmosphere in the glove box, this epoxy resin and cerium oxide (CeO _1.75 ) having oxygen deficiency coated with 7.5% of SiO ₂ obtained in (3) of Example 1 were each 50 quality. Were weighed, kneaded manually, and cured on a hot plate (set temperature 250 ° C.). The presence or absence of gas generation during the curing was visually observed. The results are shown in Table 9.

[Comparative Example 11]
This comparative example is an example using an epoxy resin which is a thermosetting resin instead of the low density polyethylene used in Comparative Example 1. The epoxy resin was cured using the components shown in Table 9. Inorganic oxide-coated cerium oxide and epoxy resin were mixed in the same manner as in Example 21. About the resin composition obtained in this way, the presence or absence of gas generation during mixing was visually observed. The results are shown in Table 9.

As is clear from the results shown in Table 9, even when a thermosetting resin is used as the resin, the resin compositions of the examples can cure the resin and suppress gas generation. I understand. In contrast, in the resin composition of the comparative example, cerium oxide having oxygen deficiency decomposes the curing agent by extracting oxygen atoms from the hydroxyl group in the curing agent (phenol novolac resin). Gas evolution was observed.

According to the present invention, an oxygen scavenger (resin composition) having improved chemical stability when used in combination with a resin is provided.

Claims (17)

1. A fluorite-type cerium oxide particle having a reversible oxygen deficiency represented by CeO _x (where x represents a positive number less than 2) is included, and the surface of the particle is covered with an inorganic oxide. Oxygen agent.
2. The inorganic oxide is at least one selected from M _y O _z (M represents an element that does not cause a valence change, and y and z represent a positive number) and a composite oxide of the element M and cerium oxide. The oxygen scavenger according to claim 1.
3. _{3. The} oxygen scavenger according to claim 1, wherein the inorganic oxide is at least one selected from SiO ₂ , Al ₂ O ₃ , a composite oxide of Si and Ce, and a composite oxide of Al and Ce.
4. The oxygen scavenger according to any one of claims 1 to 3, comprising 3 to 50 parts by mass of the inorganic oxide with respect to 100 parts by mass of the cerium oxide.
5. A deoxidizing resin composition comprising the deoxidizing agent according to any one of claims 1 to 4 and a thermoplastic resin or a thermosetting resin.
6. 6. The oxygen-absorbing resin composition according to claim 5, wherein a mixing ratio of the oxygen-absorbing agent and the thermoplastic resin or the thermosetting resin is expressed by a mass ratio of the former: the latter = 10: 90 to 80:20. .
7. The deoxygenated resin composition comprises the thermoplastic resin;
   The oxygen-absorbing resin composition according to claim 5 or 6, which has a shape of a pellet, a strand, a film, or a cup.
8. The deoxygenated resin composition contains the thermosetting resin,
   The deoxygenated resin composition according to claim 5 or 6, which has an arbitrary shape according to a use scene.
9. The oxygen scavenger according to any one of claims 1 to 4 or the oxygen scavenging resin composition according to any one of claims 5 to 8 is encapsulated in a package having air permeability resistance. Deoxygenated packaging body.
10. The deoxygenated package according to claim 9, wherein the package further contains a desiccant or a deodorant.
11. A deoxygenated film having a deoxygenating layer containing the deoxidizing agent according to any one of claims 1 to 4.
12. Provided on the outermost surface on the other surface side, the deoxygenation layer, the gas barrier layer provided on the one surface side, the oxygen permeable layer provided on the other surface side, the adhesive layer provided between the layers. The deoxygenated film according to claim 11, further comprising an adhesive layer for heat sealing.
13. An electronic device comprising a film comprising the deoxygenated resin composition according to any one of claims 5 to 8.
14. An electronic device having the deoxygenated resin composition according to any one of claims 5 to 8.
15. The electronic device according to claim 14, wherein the deoxygenated resin composition is in the form of a film or in the form of a sealing material.
16. A deoxidizing adhesive comprising the deoxidizing agent according to any one of claims 1 to 4 and an adhesive composition.
17. A deoxygenated ink comprising the deoxidant according to any one of claims 1 to 4 and an ink composition.

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