JP2002126508A - Oxygen absorption material for blending resin, oxygen absorbing resin composition and oxygen absorbing packaging material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oxygen absorption material for blending a resin, in which an oxygen absorbing resin composition having excellent dispersibility of reductive iron powder is obtained by being blended with a matrix resin, to obtain an oxygen absorbing resin composition using the same, and to provide an oxygen absorbing packaging material having excellent outward appearance obtained by reducing the agglomerate of reductive iron powder. SOLUTION: In the oxygen absorption material for blending the resin containing reductive iron powder as a main component, fine powder for enhancing dispersibility of reductive iron powder is incorporated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxygen absorbing material for blending a resin, an oxygen absorbing resin composition using the same, and an oxygen absorbing packaging material. More specifically, an oxygen-absorbing material for resin blending, in which an oxygen-absorbing resin composition excellent in dispersibility of reducing iron powder is obtained by being blended in a matrix resin, an oxygen-absorbing resin composition using the same And an oxygen-absorbing packaging material.

[0002]

2. Description of the Related Art Conventionally, after filling contents such as foods and medicines into containers such as pouches, cups and trays, the purpose of the invention is to prevent the quality of the contents from deteriorating due to residual oxygen in the containers.
BACKGROUND ART Oxygen-absorbing packaging materials such as films and sheets made of an oxygen-absorbing resin composition utilizing an oxidation-reduction reaction are known. Such an oxygen-absorbing packaging material is, for example,
No. 21083, and 50 to 40 parts by weight per 100 parts by weight of a thermoplastic resin (matrix resin).
It was composed of an oxygen-absorbing resin composition containing 0 parts by weight of 100 mesh or more reducing iron powder, 2 parts by weight or more of 100 mesh or more sodium chloride, and 5 parts by weight or more of a hydrophilic filler. . On the other hand, Japanese Patent Laid-Open No.
Japanese Patent Application Publication No. JP-A-2003-115139 discloses an oxygen absorber in which a solid such as polyethylene having a heat of fusion of 190 mJ / mg or more and a melting point of 80 ° C. to 150 ° C. is added to an oxygen absorber.

[0003]

However, in the conventional oxygen absorbent disclosed in Japanese Patent Publication No. 7-21083 mentioned above, it is easy to uniformly mix the reducing iron powder into the thermoplastic resin. However, there was a problem that the reduced iron powder easily aggregated in the thermoplastic resin. In addition, although a hydrophilic filler was added, it was added to increase the water content in the oxygen-absorbing resin composition, and was not added to improve the dispersibility of the reducing iron powder. . On the other hand, in the oxygen absorber disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 10-130463, solid such as polyethylene is added to the oxygen absorber. The solid is not added to improve the dispersibility of the reducible iron powder by suppressing the oxidation reaction of the oxygen absorbent by suppressing the contact with the air by covering the air, thereby suppressing heat generation.

[0004] Therefore, in the conventional oxygen-absorbing packaging material, molding defects such as pinholes during film formation and appearance defects of the oxygen-absorbing packaging material occur due to agglomerates of reducing iron powder. The problem was seen. In addition, in order to prevent the formation of aggregates of the reducing iron powder, it is necessary to strictly control the average particle size of the reducing iron powder to be used or to excessively lengthen the dispersion time of the reducing iron powder. There were also manufacturing problems. Further, in a container that requires easy peelability, there is also a problem that the heat seal that gives the easy peelability is affected. Then, the inventor of the present invention diligently studied such a problem, and found that the reducing iron powder contained in the thermoplastic resin (matrix resin) by containing fine powder for improving the dispersibility of the reducing iron powder. It was found that they can be mixed uniformly.
That is, an object of the present invention is to provide an oxygen-absorbing resin composition excellent in moldability and an oxygen-absorbing packaging material excellent in appearance by reducing the number of aggregates of the reducing iron powder.

[0005]

According to the present invention, there is provided an oxygen absorber containing a reducing iron powder as a main component, the resin comprising a fine powder for improving the dispersibility of the reducing iron powder. An oxygen absorber for compounding is provided, and the above-mentioned problems can be solved. That is, when such an oxygen absorbing material for compounding a resin is mixed with the matrix resin, the reducing iron powder can be uniformly mixed in the matrix resin without agglomerating, and the oxygen absorbing resin composition having excellent moldability. An oxygen-absorbing packaging material having excellent properties and appearance can be provided.

Further, in constituting the oxygen absorbing material for blending a resin of the present invention, the content of the fine powder is preferably in the range of 2 to 10% by weight based on the amount of the reducing iron powder. By limiting the content of the fine powder in this manner, the number of aggregates per unit area of the reducing iron powder can be further reduced, and the mixing of the reducing iron powder and the fine powder becomes easy, As a result, the production of the oxygen absorbing material for resin blending becomes easy.

Further, in constituting the oxygen absorbing material for resin blending of the present invention, the average particle size of the fine powder is 0.01 to 50 μm.
m. By limiting the average particle size of the fine powder in this way, the number of aggregates per unit area of the reducing iron powder can be further reduced,
Mixing of the reducing iron powder and the fine powder becomes easy, and as a result, the production of the oxygen absorbing material for blending resin becomes easy.

Another aspect of the present invention is an oxygen-absorbing resin composition containing any of the above-described oxygen-absorbing materials for resin blending and a matrix resin. With such a configuration, the number of agglomerates of the reducing iron powder is reduced, no pinholes are generated, an oxygen absorbing layer having a uniform thickness can be easily formed, and oxygen having excellent moldability is obtained. An absorbent resin composition can be provided.

In constituting the oxygen-absorbing resin composition of the present invention, it is preferable that the fine powder is the same kind of resin as the matrix resin. By using the same type of the fine powder and the matrix resin as described above, the compatibility between the two resins is improved, the interface between the two resins is not present, and the dispersibility of the reducing iron powder can be further improved. With
Adhesion between an oxygen-absorbing layer composed of an oxygen-absorbing resin composition and an adjacent layer can be improved.

Another embodiment of the present invention is an oxygen-absorbing packaging material including an oxygen-absorbing layer comprising the above-described oxygen-absorbing resin composition. With this configuration, the number of aggregates of the reducing iron powder is reduced, and an oxygen-absorbing packaging material having excellent appearance can be provided.

[0011]

Embodiments of the present invention will be specifically described below with reference to the drawings. The drawings referred to merely schematically show the sizes, shapes, and arrangements of the components to the extent that the present invention can be understood, and are not limited to the illustrated examples.

[First Embodiment] A first embodiment is directed to an oxygen absorbing material for resin blending containing a reducing iron powder as a main component, and a fine powder for improving the dispersibility of the reducing iron powder. Is an oxygen absorber for compounding a resin. Hereinafter, the reductive iron powder and the salt, which are the main components, and the fine powder for improving the dispersibility of the reducible iron powder will be described separately.

1. Reducing Iron Powder (1) Type 1 Any type of reducing iron powder (oxygen absorbent) may be used as long as it is an iron powder obtained by a reduction method. Reduced iron powder obtained by heat-treating a scale using a furnace while using a reducing material, or reduced iron obtained by further reducing or finishing heat-treating in hydrogen gas or decomposed ammonia gas It is preferred to use a powder. Such a reducing iron powder can be easily oxidized by a salt, water and oxygen described later, and as a result, can exhibit excellent oxygen absorption performance. In addition, since such a reducing iron powder is porous and has a large surface area, it can exhibit excellent oxygen absorption performance over a long period of time.

Examples of the iron compound which is a raw material of the reducing iron powder include FeOOH, Fe (OH) ₃ , FeC
l ₃ , FeSO ₄ , and iron oxide. Examples of the iron oxide include ilmenite, magnetite, limonite, siderite, pyrite, α-Fe ₂ O ₃ , γ-Fe ₂ O ₃ , and Fe ₃ O _4. No. In addition, as a reducing agent for obtaining the reducing iron powder, coke may be mentioned, but a reducing gas such as hydrogen ammonia may also be used. Further, examples of a furnace for obtaining the reducing iron powder include a fluidized-bed furnace, a rotary kiln, and a tunnel kiln. The finish reduction or finish treatment for obtaining the reducing iron powder is 400 to
It is preferably performed at a temperature of about 900 ° C., and the reduction firing of the iron compound is generally preferably performed at a temperature of about 400 to 1,300 ° C.

(2) Type 2 As the reducing iron powder, it is preferable to use the reducing iron powder obtained by the following production method alone or in combination with the above-mentioned reducing iron powder. 1) Reducing iron powder obtained by electrolytic deposition of iron from an aqueous solution containing iron ions 2) Reducing iron powder obtained by spraying (atomizing) molten iron into a non-oxidizing atmosphere 3) Pure metallic iron Iron powder obtained by crushing iron 4) Reduced iron powder obtained by steam pyrolysis of carbonyl iron

(3) Trace elements The content of copper in the reducible iron powder is set to a value of 150 ppm or less, and the content of sulfur in the reducible iron powder is set to 500 pp.
It is preferable to set the value to m or less. The reason for this is that by limiting the amount of the trace elements in this way, it is possible to prevent the deterioration of the matrix resin to be mixed and to improve the flavor retention. Therefore, it is more preferable that the content of copper in the reducing iron powder be set to a value of 100 ppm or less and the content of sulfur in the reducing iron powder be set to a value of 300 ppm or less.

(4) Physical properties The specific surface area of the reducing iron powder is set to a value of 0.5 m ² / g or more,
It is preferable that the apparent density be 3 g / cm ³ or less. The reason is that when the specific surface area is less than 0.5 m ² / g, or when the apparent density exceeds ³ g / cm ³ , the oxygen absorption rate by the reducing iron powder may decrease. Therefore, the specific surface area of the reducing iron powder is set to a value of 1.0 m ² / g or more, and the apparent density is set to 2 g / cm ^3.
The following values are more preferable.

(5) Average Particle Size The average particle size of the reducing iron powder is preferably in the range of 1 to 50 μm, more preferably in the range of 2 to 40 μm, and more preferably in the range of 3 to 30 μm. More preferred. The reason is that, when the average particle size of the reducing iron powder is out of these ranges, the dispersibility of the reducing iron powder may be reduced or the oxygen absorption may be reduced when blended in the matrix resin. That's why. The average particle size of the reducing iron powder can be measured by a laser scattering method.

2 Salts (1) Kinds Salts (sometimes referred to as metal halides) are generally water-soluble compounds, and are the first, second and third groups of the periodic table.
A chloride containing a Group B, Group 4B or Group 8 metal is preferably used. The reason for this is that by adding such a salt, the reducing iron powder can be easily oxidized and exhibit excellent oxygen absorption. More specifically,
Sodium chloride, potassium chloride, calcium chloride, zinc chloride, aluminum chloride, ferric chloride (FeCl ₃ ),
A single salt such as tin chloride (SnCl ₂ ) or a combination of two or more thereof may be mentioned, and a more preferable salt among these compounds is sodium chloride (salt).

(2) Mixing ratio In the oxygen-absorbing resin composition, the mixing ratio (weight ratio) of the reducing iron powder and the salt is 100: 0.1 to 100: 3.
It is preferably a value in the range of 0, and 100: 1 to 1
More preferably, the value is in the range of 00:10. The reason for this is that by setting the mixing ratio of the reducing iron powder and the salt to a value within such a range, an excellent oxygen absorption rate can be obtained, and also excellent water resistance and mechanical properties can be obtained. is there.

3. Fine powder for improving dispersibility of reducible iron powder (1) Type 1 As fine powder for improving dispersibility of reducible iron powder (hereinafter sometimes simply referred to as fine powder), inorganic powder is used. It is preferable to mix a system-based fine powder and an organic-based fine powder, or any one of them. By adding these fine powders, the dispersibility when the reducing iron powder is mixed with the matrix resin can be dramatically improved. Further, as such inorganic fine powder, synthetic silica or the like, and on the other hand, as organic fine powder, polyolefin fine particles such as polyethylene and polypropylene, polyamide fine particles, polyester fine particles, acrylic fine particles, or one or more of these. Combinations.

(2) Type 2 The type of the fine powder is preferably the same resin as the matrix resin in the oxygen-absorbing resin composition described below. With this configuration, the compatibility between the fine powder and the matrix resin is improved, and no interface exists between the two resins. Therefore, the dispersibility of the reducing iron powder can be further improved, and the adhesion between the oxygen-absorbing layer made of the oxygen-absorbing resin composition and an adjacent layer can be improved. For example, when the matrix resin is made of low-density polyethylene from the viewpoint of easy tearing, fine particles are selected by matching low-density polyethylene fine particles, and when using polypropylene from the viewpoint of retort resistance, fine polypropylene particles are selected. It is particularly preferred to do so.

(3) Average Particle Size The average particle size of the fine powder is preferably set to a value within the range of 0.01 to 50 μm. This is because if the average particle size of the fine powder is less than 0.01 μm, it may be difficult to improve the dispersibility of the reducing iron powder,
If the average particle size of the fine powder exceeds 50 μm, on the contrary, the dispersibility of the reducing iron powder may decrease, or the mixing property with the matrix resin may decrease. Therefore, the average particle size of the fine powder is more preferably set to a value in the range of 0.1 to 30 μm, and further preferably to a value in the range of 1 to 20 μm.

It is preferable that the average particle size of the fine powder is determined in consideration of the average particle size of the reducing iron powder. Specifically,
The ratio (d1 / d2) of the average particle size (d1) of the fine powder to the average particle size (d2) of the reducing iron powder is preferably in the range of 1/100 to 2. The reason is that if d1 / d2 is larger than 2, it may be difficult to improve the dispersibility of the reducing iron powder, whereas d1
If / d2 is smaller than 1/100, it may be difficult to mix the fine powder with the reducing iron powder.

(4) Addition amount The addition amount of the fine powder is set to 1
When it is set to 00% by weight, it is preferably in the range of 2 to 10% by weight, more preferably in the range of 2.5 to 10% by weight, and still more preferably in the range of 3 to 10% by weight. . The reason is that the amount of the fine powder added is 2
If the content is less than 10% by weight, the dispersibility of the reducing iron powder is insufficiently improved, and the number of aggregates per unit area may increase. If the amount of the fine powder exceeds 10% by weight, it becomes difficult not only to mix the fine powder with the reducing iron powder but also to mix the oxygen absorbing material for resin blending into the matrix resin. It is because it becomes.

This point will be described in more detail with reference to FIG. In FIG. 2, the abscissa indicates the amount (% by weight) of the polyethylene fine powder in the oxygen absorber for resin blending, and the ordinate indicates the aggregates per unit area of the oxygen-absorbing resin composition. The numbers (pieces / m ² ) are shown. In addition, as a measured aggregate, for convenience, the diameter is 100 μm to 30 μm.
It is intended to be of 0 μm. As is easily understood from FIG. 2, the larger the amount of the fine powder added in the oxygen absorbing material for resin blending, the more the number of aggregates per unit area of the oxygen absorbing resin composition tends to be significantly reduced. Was. For example, when no fine powder is added, the number of such aggregates is 34 /
m ² , when 1.5% by weight of fine powder was added to the oxygen absorber for resin blending, the number of such aggregates was 1
The number decreased to 9 particles / m ² , and when 3% by weight of fine powder was further added, the number of such aggregates was reduced to 0 particles / m ² . Therefore, the number of aggregates per unit area (pieces / m ² ) of the oxygen-absorbing resin composition can be easily controlled by adjusting the amount (% by weight) of the fine powder in the oxygen absorbing material for resin blending. It was confirmed.

(5) Addition method In addition, when a fine powder is mixed with a reducing iron powder to form an oxygen absorbing material for blending a resin, for example, a V-type blender, a conical blender, a super mixer, a Henschel mixer or the like is used. And dry blending. Specifically, for example, after a fine powder and a reducing iron powder are stored in a mixing chamber using a V-type blender, the frequency (5
To 100) times / min, and the stirring time is preferably in the range of 5 minutes to 24 hours. In addition, when the stirring temperature is 10
It is preferable to set it to the range of ６０60 ° C., more preferably to the range of 20-50 ° C. Prior to such dry blending, it is also preferable that the salt is firmly adhered to the surface of the reducing material, for example, the reducing iron powder, by an adhesion treatment in advance. That is, it is preferable to mix the reducing iron powder and the salt in advance using dry milling, for example, using a vibration mill, a ball mill, a tube mill, a super mixer, or the like. By pre-mixing the reducing iron powder and the salt in this way, the oxygen absorbing properties of the reducing iron powder can be more effectively exhibited. In addition, since the same effect can be obtained, as the adhesion treatment, the surface of the reducing iron powder,
It is also preferred to wet coat the salt. Such wet coating is performed by spraying an aqueous solution of a salt or a solution of an organic solvent (for example, ethanol, acetone, or ether) onto the reducing material, or impregnating these solutions with the reducing material and then removing the solvent. Is preferred.

[Second Embodiment] A second embodiment is an oxygen-absorbing resin composition containing an oxygen-absorbing material for blending a resin and a matrix resin. Hereinafter, the matrix resin which is a feature of the second embodiment will be mainly described.

(1) Type of matrix resin Examples of the matrix resin include low-density polyethylene (LDPE) and linear low-density polyethylene (LLDP).
E), polyolefin resins such as high-density polyethylene (HDPE), polypropylene, poly 1-butene, poly 4-methyl-1-pentene; ethylene-vinyl acetate copolymer; polyamide resins; Alternatively, a combination of two or more types may be used.

Further, as the matrix resin, a rubber material or a thermoplastic elastomer can be used. For example, ethylene-propylene rubber (EPR), ethylene-propylene-diene rubber (EPDM) and the like can be mentioned.

The matrix resin described above preferably has excellent oxygen permeability because it can rapidly absorb oxygen. Therefore, olefin resins, for example, low-density polyethylene and linear low-density polyethylene are particularly suitable. In other words, such an olefin-based resin is a resin having a relatively low water retention property, but the coexistence of a salt makes it possible to smoothly supply water necessary for oxygen absorption.
Also, among the thermoplastic elastomer resins described above,
EPR and E also have excellent oxygen permeability.
PDM is particularly suitable.

Addition amount The amount of the matrix resin to be added was adjusted according to the
It is preferable that the content be in the range of 50 to 10,000 parts by weight per 00 parts by weight. The reason for this is that if the amount of the matrix resin is less than 50 parts by weight, the moldability of the oxygen-absorbing resin composition may decrease, while the amount of the matrix resin added is 10,000 parts by weight. If the amount exceeds the part, the amount of the reducing iron powder is relatively reduced, and the oxygen absorbability may be reduced. Therefore,
The amount of matrix resin to be added should
It is more preferably in the range of 100 to 5,000 parts by weight, more preferably in the range of 200 to 2,000 parts by weight, per 100 parts by weight.

(2) Additives In the oxygen-absorbing resin composition,
It is preferable to incorporate a known oxidation promoter or moisture retaining agent. These oxidation promoters may be blended in the thermoplastic resin in the form of oxygen absorbent particles, or may be blended in the thermoplastic resin separately from the oxygen absorbent particles.

[Third Embodiment] In a third embodiment, as shown in FIG. 1, an outer layer 6 and a second adhesive layer 4 are arranged from above.
b, the gas barrier layer 5, the oxygen absorbing layer 3, and the inner layer (concealing layer) 2, and a first adhesive between the gas barrier layer 5 and the oxygen absorbing layer 3 as an optional component. An oxygen-absorbing packaging material 1 comprising an agent layer 4a and a flattening layer 7, which is used as a film-shaped pouch, a cup, a sealing lid for a tray, or a sheet-shaped material for the cup or tray container. The third embodiment is characterized in that the oxygen absorbing layer 3 is made of the oxygen absorbing resin composition according to the second embodiment. Hereinafter, the oxygen-absorbing packaging material 1 of the third embodiment will be specifically described.

(1) Outer Layer (Protective Layer) The protective layer of the oxygen-absorbing packaging material is provided for mechanically protecting the oxygen-absorbing layer and supporting a barrier layer described later. For this purpose, a layer composed of a continuous layer of thermoplastic resin (impermeable layer) can be suitably used. As the thermoplastic resin constituting such a protective layer, it is preferable to use the same resin as the resin constituting the oxygen absorption layer described later, but more preferably, mechanical strength, piercing resistance, or heat resistance It is appropriate to use a more excellent one. For this reason, olefin-based resins, nylon-based resins, polyester-based resins, and the like stretched uniaxially or biaxially are more preferably used.

(2) Barrier Layer A barrier layer (sometimes referred to as a gas barrier layer) is provided to prevent intrusion of oxygen and the like in the air. For this purpose, a metal foil, a gas barrier resin, or An inorganic vapor-deposited film is used. Examples of such metal foils include light metal foils such as aluminum and aluminum alloys, iron foils, steel foils, tin foils, and steel foils such as surface-treated steel foils.

As the gas barrier resin, a thermoplastic resin having a low oxygen permeability coefficient and capable of being thermoformed is preferable. Examples of such a gas barrier resin include an ethylene-vinyl alcohol copolymer and polyamides. For example, when the gas barrier resin is an ethylene-vinyl alcohol copolymer, the ethylene content is preferably 20 to 60 mol%, and the saponification degree is preferably 96 mol% or more. When the barrier layer is the above-mentioned metal foil or gas barrier resin, the barrier layer is laminated on the above-mentioned outer layer. In this case, as shown in FIG. 1, a first adhesive composed of an adhesive is used. The barrier layer 4 and the outer layer 2 are stacked using the layer 4a.

Examples of the inorganic vapor-deposited film include a resin film obtained by vapor-depositing silica, alumina, etc. on the above-mentioned outer layer film. Is preferred.
That is, the vapor deposition layer serves as a barrier layer, and the resin film layer serves as the outer layer described above.

(3) Oxygen Absorbing Layer The same contents as in the second embodiment can be adopted.

(4) Inner Layer Oxygen Permeability Coefficient and Water Vapor Permeability Coefficient As an inner layer of the oxygen-absorbing packaging material, 7.5 × 10 ^-15 to
2.3 × 10 ^-12 cm ³ · cm / cm ² · sec · Pa
(25 ° C., 100% RH, hereinafter the same measurement conditions) and 7.5 × 10 ^{−14 to} 1.5.
× 10 ⁻¹⁰ cm ³ · cm / cm ² · sec · Pa (25
It is preferable to use a thermoplastic resin having a water vapor transmission coefficient of (° C., hereinafter the same measurement conditions). The reason is that the oxygen permeability coefficient is 7.5 × 10 ⁻¹⁵ cm ³ · cm / cm ² · s
If the value is less than ec · Pa, the permeation amount of oxygen decreases,
Oxygen absorption may decrease, while oxygen permeability coefficient is 2.3 × 10 ⁻¹² cm ³ · cm / cm ² · sec · P
If the value is larger than a, the oxygen absorbency may be deactivated early. Further, the water vapor transmission coefficient is 7.
When it is less than 5 × 10 ⁻¹⁴ cm ³ · cm / cm ² · sec · Pa, the activation of the oxygen absorbent may be remarkably reduced, while the water vapor transmission coefficient is 1.5 × 10 ⁻¹⁰ cm ³ · Pa. c
If the value is greater than m / cm ² · sec · Pa, the water resistance may decrease.

Heat Sealability As the inner layer in contact with the oxygen-absorbing layer, the oxygen-absorbing packaging material 1 of the present embodiment is sealed in a container such as a pouch, a cup or a tray, or in a container such as the cup or a tray. It has heat sealing properties because it is used for sealing lids. Therefore, since the melting point is relatively low and heat sealing can be performed in a short time, the resin constituting the inner layer may be low-density polyethylene, medium-density polyethylene, or high-density polyethylene, linear low-density polyethylene, or isotactic. Polypropylene, ethylene-propylene copolymer, polybutene-1, ethylene-butene-1 copolymer, propylene-butene-1 copolymer, ethylene-propylene-butene-1 copolymer, ethylene-vinyl acetate copolymer, And ion-crosslinked olefin copolymers (ionomers), or blends of these resins.

Hiding Agent The inner layer preferably contains a hiding agent, for example, a white pigment, for the purpose of hiding the oxygen absorbing layer from being colored by the reducing iron powder. Titanium dioxide is preferred as such a white pigment because of its high hiding power, and more preferred is titanium dioxide having an anatase-type crystal structure. Further, the compounding amount of the concealing agent is adjusted to 100 parts of the constituent resin of the inner layer.
The value is preferably in the range of 1 to 20 parts by weight per part by weight. The reason for this is that if the compounding amount of the concealing agent is less than 1 part by weight, the concealing property may be reduced. On the other hand, if the compounding amount of the concealing agent exceeds 20 parts by weight, it is uniformly dispersed. This is because it may be difficult.

(5) Flattening Layer When laminating the barrier layer and the oxygen absorbing layer described above, unevenness due to the oxygen absorbing agent is formed on the surface of the oxygen absorbing layer, which may cause poor adhesion and poor appearance. In order to prevent this, it is preferable to interpose a flattening layer. As a resin constituting such a flattening layer, the same kind of resin as that used for the oxygen absorbing layer described above can be used.
When a transparent or translucent resin film of ethylene-vinyl alcohol copolymer, polyamide, or the like, or a resin film on which silica or the like is deposited is used as the barrier layer, an inner layer is formed on the flattening layer. It is preferable to blend a concealing agent, for example, a white pigment such as titanium dioxide, for the purpose of concealing the coloring of the oxygen absorbing layer by the reducing iron powder in the same manner as described above.

(6) Adhesive Layer As the adhesive layer, an ion-crosslinked olefin copolymer, maleic anhydride-grafted polyethylene, maleic anhydride-grafted polypropylene, acrylic acid-grafted polyolefin, etc. are used for bonding the above-mentioned barrier layer and flattening layer. Singly or in combination of two or more. Further, since a more excellent adhesive force can be obtained, carbonyl (-C
The (好 ま し い O)-) group is preferably contained in the main chain or side chain at a concentration of 1 to 700 milliequivalents (meq) / 100 g resin. Further, when the above-described barrier layer is previously laminated on the protective layer, it is also preferable to use a thermosetting adhesive such as an isocyanate-based resin or an epoxy-based resin.

(7) Object Oxygen-absorbing packaging material is mainly used as a container material, and its form is applied to a pouch (bag), cup, tray or a sealing lid for sealing the above cup, tray, bottle, etc. , And can exhibit excellent storage stability. Also,
The target content is useful for foods such as cooked rice, retort foods such as curry and stew, dry foods such as tea leaves, semi-dry foods such as fresh confectionery, castella, pharmaceuticals such as infusion bags and compresses, and cosmetics.

[0046]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail based on embodiments. Needless to say, the present invention is not limited to the description of the examples, and various changes can be made without impairing the object of the present invention.

Example 1 1: Preparation of Oxygen-Absorbing Wrapping Material (Film) (a) Preparation of Oxygen-Absorbing Material for Mixing Resin Using a V-type blender, fine polyethylene powder having an average particle diameter of 6 μm (Sumitomo Seimitsu) (Flow beads) and average particle size 2
5 μm of reduced iron powder and an oxygen absorbent composed of sodium chloride were dry-blended under the conditions of a vibration frequency of 30 times / minute, a stirring time of 30 minutes and a stirring temperature of 25 ° C. The blend ratio is
Polyethylene fine powder 2wt%, oxygen absorber 98w
t%.

(B) Preparation of Oxygen-Absorbing Resin Composition The oxygen-absorbing material for compounding resin was supplied to a twin-screw extruder from a screw type compactor, and LDPE (Sumitomo Chemical Co., Ltd. L2
After melt-mixing with 11), the mixture was pelletized to prepare an oxygen-absorbing resin composition. The blend ratio was 30 wt% for the oxygen absorber for resin blending and 70 wt% for LDPE.

(C) Preparation of Oxygen-Absorbing Wrapping Material Using a co-extrusion blown film molding apparatus, a three-layer co-extruded film composed of an inner layer, an oxygen absorbing layer and a flattening layer having the following constitution was prepared. Inner layer: LDPE (Sumitomo Chemical Co., Ltd. L211) 10
20 μm thick composed of a composition containing 15 parts by weight of titanium oxide (titanium white) having an average particle size of 2.5 μm per 0 parts by weight.
m concealing layer Oxygen absorbing layer: thickness 2 composed of the oxygen absorbing resin composition
5 μm layer Flattening layer: 15 μm thick layer made of LDPE (Sumitomo Chemical Co., Ltd. L211) The flattening layer of the three-layer coextruded film was subjected to corona treatment, and then a urethane-based adhesive was applied. Then, aluminum foil (7μ) was obtained by dry lamination.
m), a urethane-based adhesive layer and a polyethylene terephthalate film (12 μm) were sequentially laminated to obtain an oxygen-absorbing packaging material.

2: Evaluation (a) Evaluation of Mixing Suitability of Oxygen Absorber for Resin into Matrix Resin After performing melt mixing using a twin-screw extruder for 4 hours continuously,
Residual state of oxygen absorber for resin blending on screw surface in compactor (Fixed state of polyethylene fine powder)
Was visually evaluated. The evaluation was made in the following three stages. Excellent: No sticking Good: There is some sticking, but continuous mixing is impossible.

(B) Evaluation of film-forming properties The number of pinholes per unit area in the three-layer coextruded film was visually measured. The evaluation was made in the following three stages. Yu: No pinhole Good: 0.1 pieces / m ² less than not: 0.1 pieces / m ² or more

(C) Number of Aggregates of Oxygen-Absorbing Packaging Material The number of agglomerates (particle size of 100 μm or more) in the oxygen-absorbing layer of the obtained oxygen-absorbing packaging material for evaluation was visually measured. .

(D) Appearance characteristics Using the obtained oxygen-absorbing packaging material for evaluation, 65 mm × 7
8mm pouch is made and appearance characteristics are visually excellent, good,
The evaluation was made on a three-point scale.

Example 2 The addition amount of the polyethylene fine particles in the oxygen absorbing material for resin blending in Example 1 was 3% by weight.
Other than that, an oxygen-absorbing packaging material was prepared and evaluated in the same manner as in Example 1.

Example 3 The addition amount of the polyethylene fine particles in the oxygen absorbing material for resin blending in Example 1 was 5% by weight.
Other than that, an oxygen-absorbing packaging material was prepared and evaluated in the same manner as in Example 1.

Example 4 An oxygen-absorbing packaging material was prepared in the same manner as in Example 1, except that the amount of the polyethylene fine particles in the oxygen-absorbing material for resin blending in Example 1 was changed to 10% by weight. evaluated.

[Comparative Example 1] The addition amount of the polyethylene fine particles in the oxygen absorbing material for resin blending in Example 1 was 0% by weight.
Other than the above, an oxygen-absorbing packaging material was prepared and evaluated in the same manner as in Example 1.

Comparative Example 2 An oxygen-absorbing packaging material was prepared in the same manner as in Example 1, except that the amount of the polyethylene fine particles in the oxygen-absorbing material for resin blending in Example 1 was changed to 0.5% by weight. Was evaluated.

Comparative Example 3 An oxygen-absorbing packaging material was produced in the same manner as in Example 1, except that the amount of the polyethylene fine particles in the oxygen-absorbing material for resin blending in Example 1 was changed to 1.5% by weight. Was evaluated.

Comparative Example 4 An oxygen-absorbing packaging material was prepared and evaluated in the same manner as in Example 1, except that the amount of the polyethylene fine particles in the oxygen-absorbing material for resin blending in Example 1 was changed to 11% by weight. did. The results obtained in the above Examples and Comparative Examples are shown in Table 1 and FIG.

[0061]

[Table 1]

[0062]

According to the oxygen-absorbing material for compounding a resin of the present invention, by containing fine powder for improving the dispersibility of the reducing iron powder, it is possible to reduce the reduction when mixed with the oxygen-absorbing packaging material. It is possible to provide an oxygen-absorbing wrapping material which has less agglomerates of conductive iron powder and excellent appearance. In addition, since the reduced iron powder is not aggregated by the action of the added fine powder, the handleability of the oxygen absorber for blending resin is also facilitated. Furthermore, according to such an oxygen absorber for compounding a resin, it is not necessary to strictly control the average particle size of the reducing iron powder, and moreover, since the reducing iron powder can be dispersed in a short time, it is economical. Thus, an oxygen-absorbing resin composition can be produced. Further, according to the oxygen-absorbing resin composition of the present invention, the number of agglomerates of the reducing iron powder contained is reduced, and an oxygen-absorbing layer having a uniform thickness can be easily formed. Further, according to the oxygen-absorbing packaging material of the present invention, the number of agglomerates of the reduced iron powder contained therein is reduced, and an oxygen-absorbing packaging material having excellent appearance can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of an oxygen-absorbing packaging material according to a third embodiment.

FIG. 2 is a graph showing the relationship between the amount of fine powder added (% by weight) and the number of aggregates per unit area (pieces / m ² ).

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 oxygen absorbing packaging material 2 inner layer 3 oxygen absorbing layer 4 a first adhesive layer 4 b second adhesive layer 5 gas barrier layer 6 outer layer 7 flattening layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 3/08 C08K 3/08 7/00 7/00 C08L 101/00 C08L 101/00 // A23L 3 / 3436 501 A23L 3/3436 501 F term (reference) 3E086 AB01 AD01 AD05 AD06 BA04 BA15 BA35 BB05 CA01 CA28 4B021 LA17 MC04 MK10 4F100 AB02A AB02H AK01A AK04A AT00B BA02 BA10A BA10B DE01A DE01H GB20A14 Y20 ACA BA03 CA37 DA03 EA07 FA20 FA25 FA37 4J002 AA001 AA002 BB021 BB022 BB061 BB111 BB112 BB151 BB171 BG002 CF001 CF002 CL001 CL002 DA086 DJ017 FD012 FD017 FD206 GG02

Claims (6)

[Claims] 1. An oxygen absorbing material for resin blending containing reducing iron powder as a main component, wherein the oxygen absorbing material contains fine powder for improving the dispersibility of the reducing iron powder. Absorbent. 2. The oxygen absorber according to claim 1, wherein the content of the fine powder is in the range of 2 to 10% by weight based on the amount of the reducing iron powder. 3. An average particle size of the fine powder is 0.01 to 5
3. The method according to claim 1, wherein the thickness is within a range of 0 μm.
The oxygen absorbing material for blending a resin according to the above. 4. An oxygen-absorbing resin composition comprising the resin-mixed oxygen absorbing material according to claim 1 and a matrix resin. 5. The oxygen-absorbing resin composition according to claim 4, wherein the fine powder is a resin of the same kind as the matrix resin. 6. An oxygen-absorbing packaging material comprising an oxygen-absorbing layer comprising the oxygen-absorbing resin composition according to claim 4 or 5.