JP2002080647A - Deoxidizing agent resin composition and sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a deoxidizing resin sheet, for preventing contamination of foods and the like by powder leakage, eating by mistake, and the like encountered in the case of a deoxidizing agent in a pouch, which sheet suitably preserves foods while inhibiting generation of hydrogen and is free from an offensive odor and the like. SOLUTION: The deoxidizing resin sheet comprises a deoxidizing resin composition comprising 15-75 pts.wt. of a polyolefin resin and 25-85 pts.wt. of an iron-based deoxidizing agent comprising iron, a metal halide and an inorganic sulfate, where the compounded amount of the inorganic sulfate in the iron-based deoxidizing agent is such that the ratio of the weight of sulfur contained in the inorganic sulfate to the weight of iron is not less than 500 ppm but not more than 5,000 ppm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxygen-absorbing composition for use in an oxygen-absorbing sheet formed by mixing a thermoplastic resin and an iron-based oxygen absorber into a mixed sheet, and more particularly to a thermoplastic resin. The present invention relates to an oxygen absorber composition characterized in that, when using an oxygen absorber sheet formed by mixing and sheeting an iron-based oxygen absorber with an iron-based oxygen absorber, generation of hydrogen can be suppressed without generating an offensive odor or an off-flavor.

[0002]

2. Description of the Related Art Conventionally, as an oxygen scavenger for maintaining the freshness of foods and the like, an oxygen scavenger composition obtained by mixing an iron-based main ingredient and an accelerating aid according to the intended use, or an organic sodium ascorbate solution An oxygen-absorbing composition impregnated with an inorganic agent, activated carbon, or the like, is partially or entirely packaged in a small bag-shaped oxygen-absorbing agent packaged with a breathable packaging material, together with food, etc. It is enclosed and used with certain packaging materials.

[0003] The oxygen absorber composition packaged in these oxygen absorber packages is powdery or granular, so that if a consumer accidentally damages a small bag of oxygen absorber with a blade or the like, There is a possibility that the oxygen scavenger composition may be scattered from the small bag and contaminate the stored food. Food manufacturers who use oxygen absorbers also cut the body of the bag-shaped oxygen absorber due to misadjustment of the dosing machine when adding the oxygen absorber when attaching it to food, It was possible that things could be scattered and contaminated on food packaging lines.

[0004] JP-A-2-072851 and JP-A-2-229840 disclose the composition of a deoxidizer in a thermoplastic resin in order to avoid the risk due to the above-mentioned contents being powdery. An oxygen absorber sheet made by kneading and extruding the material into a sheet,
A form of oxygen scavenger utilizing the same has been disclosed. These series of oxygen absorber sheets are more susceptible to powder leakage and accidental ingestion, as compared to pouch-shaped oxygen absorbers in which the powdered oxygen absorber composition is directly packaged. It can be said that it is much better because it is difficult.

The oxygen absorber using the conventional oxygen-absorbing resin composition has excellent properties as described above against powder leakage, but the resin and iron powder are kneaded. For this reason, the oxygen-absorbing resin composition sometimes emits an odor, which may deteriorate the taste and flavor of the food.
As suppression of odor, JP-A-2-298579 describes that an ethylene-vinyl alcohol copolymer is mixed with a deoxidizer having a copper content of 150 ppm or less and a sulfur content of 500 ppm or less. Japanese Patent Application Laid-Open No. 10-230160 describes the type of antioxidant to be incorporated into a resin.

[0006]

In the above-mentioned prior art, it is described that generation of odor from the oxygen-absorbing resin composition is suppressed. However, a product using the oxygen-absorbing resin composition has a high moisture content. When applied to food or medical products, or when the oxygen-absorbing resin composition is left in a humid atmosphere,
Hydrogen was sometimes generated. If the generation of hydrogen is high,
Inflating the food packaging bag to which the product oxygen absorber is applied to impair the appearance, or inflating the collective packaging bag of the product using the oxygen-absorbing resin composition which is usually in a degassed state to distinguish it from the pinhole of the outer bag. There was a problem that it became difficult to adhere.
An object of the present invention is to provide an oxygen-absorbing resin composition that can effectively suppress the generation of hydrogen while effectively suppressing the odor generated from the oxygen-absorbing resin composition.

[0007]

Means for Solving the Problems In the oxygen-absorbing resin composition obtained by mixing and forming a thermoplastic resin and an iron-based oxygen-absorbing agent into a sheet, inorganic sulfuric acid is contained in the oxygen-absorbing resin composition. It has been found that by including a salt, an oxygen-absorbing resin composition is provided which can suppress the generation of odor of the oxygen-absorbing resin composition and also the generation of hydrogen.

[0008] The present invention relates to a polyolefin resin 15-75.
Parts by weight, and a resin composition comprising 25 to 85 parts by weight of an iron-based oxygen absorber comprising iron, a metal halide and an inorganic sulfate, and a blending amount of the inorganic sulfate in the iron-based oxygen absorber. Is a deoxidized resin composition in which the weight of sulfur contained in the inorganic sulfate is 500 ppm or more and 5,000 ppm or less with respect to the weight of iron. The present invention also provides a deoxidized sheet comprising the deoxidized resin composition and a method for producing the same.

Japanese Patent Application Laid-Open No. 2-298579 describes that an oxygen scavenger having a sulfur content of 500 ppm or less is added to an ethylene-vinyl alcohol copolymer.
The present inventors have found that a resin composition comprising a polyolefin resin and an iron-based oxygen absorber, the weight of sulfur in the inorganic sulfate is 500 ppm or more and 5,000 pp with respect to the weight of iron in the iron-based oxygen absorber.
It has been found that by adding an inorganic sulfate in a weight ratio of not more than m, no odor is generated and generation of hydrogen is suppressed.

[0010] The deoxidized packaging for food and medical products using the oxygen-absorbing resin composition of the present invention has a reduced amount of hydrogen generated during storage compared to the packaging using the conventional oxygen-absorbing resin composition. Therefore, it has excellent storage stability. In addition, a product having excellent stability can be provided also in a collective package of products using the deoxygenated resin composition.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The concrete constitution of the present invention will be described below. The present invention is characterized in that an iron-based oxygen-absorbing resin composition contains an inorganic sulfate. In this case, the sulfur content (in terms of S) of the inorganic sulfate is iron weight of the iron-based oxygen-absorbing composition. For 5
It is preferably used in the range of 00 ppm to 5,000 ppm. If the sulfur content of the inorganic sulfate is less than 500 ppm with respect to iron, the effect of suppressing hydrogen generation is small, and if it is more than 5,000 ppm, stable extrusion pressure cannot be obtained when sheeting the oxygen-absorbing resin composition, resulting in stable production. It is not preferable because it cannot be done.

In the iron-based oxygen scavenger composition, the main component is iron powder,
A composition in which the accelerating aid is a metal halide and further added with an inorganic sulfate is used. The type of iron powder is not particularly limited, and reduced iron powder, sprayed iron powder, and electrolytic iron powder are used. Usually, the particle size is 200 μm or less, preferably 150 μm, so that the sheet can be easily extruded and stretched during sheet formation.
The following are used: Examples of the promoting aid used include metal chlorides such as sodium chloride, calcium chloride, iron chloride, and magnesium chloride; metal bromides such as sodium bromide, potassium bromide, and iron bromide; potassium iodide; and calcium iodide. And metal halides such as metal iodides.

[0013] The metal halide, which is a promoter, serves to increase the rate at which iron reacts with oxygen. The weight ratio of the metal halide to the iron in the oxygen scavenger composition is 0.1 to 20% by weight, preferably 0.1 to 5% by weight. It is preferable that the surface of the iron powder is coated with a metal halide or a metal halide is dispersed and attached.

As the inorganic sulfate, a water-soluble and water-insoluble inorganic sulfate is used. Specifically, calcium sulfate, barium sulfate, magnesium sulfate, sodium sulfate, potassium sulfate, aluminum sulfate or ferrous sulfate or These combinations are exemplified. It is necessary to add the inorganic sulfate so that the sulfur concentration in the inorganic sulfate is not less than 500 ppm and not more than 5,000 ppm with respect to iron in the oxygen scavenger composition. When the sulfur concentration in the inorganic sulfate is less than 500 ppm with respect to the iron in the oxygen scavenger composition, the effect of suppressing hydrogen generation is small when the sulfur concentration in the inorganic sulfate is less than 500 ppm. At the time of extrusion, classification is observed, and the extrusion pressure fluctuates, which makes it difficult to form a continuous and highly accurate sheet, which is not preferable.

[0015] In order to improve the dispersion, the inorganic sulfate to be blended has a particle size of 1/2 or less of the iron powder used, preferably 1% or less.
A particle size of / 5 or less is used. The iron powder-based oxygen absorber composition may be a mere mixture of the above components, but is preferably one in which the surface of iron powder or a mixture of iron powder and activated carbon is coated or dispersed and adhered with a metal halide salt and an inorganic sulfate. . If necessary, components such as activated carbon and poorly water-soluble fillers can be added to the present oxygen absorber composition.

The method of blending the inorganic sulfate is not particularly limited as long as it is uniformly dispersed in the oxygen-absorbing resin composition or oxygen-absorbing sheet, and examples thereof include the following methods.
A method of coating the accelerating aid after mixing the iron powder and the inorganic sulfate, extruding together with the thermoplastic resin after drying, and forming a sheet,
After coating or mixing the iron powder and the accelerating aid, the inorganic sulfate is mixed and uniformly dispersed and then extruded together with the thermoplastic resin to form a sheet, or after mixing the iron powder and the accelerating aid, the inorganic sulfate is added. And a thermoplastic resin, and then forming an extruded sheet with a deoxidizing composition containing a main agent. Further, it may be added by dispersing it in a thermoplastic resin when forming the sheet.
In the case of calcium sulfate, which coagulates by reacting with moisture, or in the case of coagulation by a combination of a promoter and an inorganic sulfate, it is preferable to select conditions for mixing under drying.

The polyolefin to be blended with the iron-based oxygen scavenger composition in the present invention includes polyethylenes exemplified by low density polyethylene, medium density polyethylene, linear low density polyethylene and high density polyethylene, polypropylene homopolymer, propylene -Polypropylenes exemplified by ethylene block copolymers and propylene-ethylene random copolymers, polyolefins by metallocene catalysts such as metallocene polyethylene and metallocene polypropylene, polymethylpentene, ethylene-vinyl acetate copolymer and ethylene-α-olefin Elastomers exemplified by the copolymer or a mixture thereof are exemplified. Among them, a propylene-ethylene random copolymer, a propylene-ethylene block copolymer, a low-density polyethylene, a linear low-density polyethylene or a metallocene polyethylene is particularly preferable.

The oxygen-absorbing resin composition of the present invention contains 15 to 75 parts by weight of a polyolefin resin and 25 to 8 parts by weight of an iron-based oxygen absorber.
5 parts by weight, and the above amount of inorganic sulfate. The deoxygenated sheet can be easily produced, for example, by the method described in JP-A-2-72851. That is, 25 to 75 parts by weight of the above-mentioned thermoplastic resin is added with 25 parts of an iron powder-based oxygen absorber.
It is kneaded, melted, sheeted and stretched in a proportion of up to 85 parts by weight. The stretching ratio is preferably 1.5 to 12 times. The thickness of the deoxidizing sheet is preferably in the range of 0.2 to 3 mm, and is appropriately selected in consideration of the required oxygen absorbing performance, workability, loadability and the like.

The oxygen-absorbing resin composition obtained in the present invention is generally used as an oxygen-absorbing sheet partially or wholly coated with a gas-permeable packaging material. The form of the oxygen-absorbing sheet can be roughly divided into two forms: a form in which the oxygen-absorbing sheet is wrapped using a gas-permeable packing material, and a form in which the air-permeable packing material and the oxygen-absorbing sheet are laminated and covered. Divided. Specific examples of the deoxygenation sheet include the following. However, the present invention is not limited to these.

1) A form in which a deoxidized sheet is wrapped with a breathable wrapping material. One side is polyethylene terephthalate / polyethylene, the other side is a water-resistant nonwoven fabric ("Tyvek" manufactured by DuPont,
"Luxer" manufactured by Asahi Kasei Corporation, etc.), a deoxygenation sheet is sandwiched between two packaging materials, and the periphery is heat sealed.

2) A label type in which a deoxidized sheet is combined with a breathable packaging material and an adhesive material. For example, a base layer having an adhesive layer / a deoxygenating sheet / a gas-permeable layer are laminated in this order, and a gas-permeable layer is directly formed on the periphery at the periphery.
Label-type form adhered to the adhesive layer, a label-type form integrated with a display label laminated in the order of breathable adhesive layer / breathable packaging material layer / deoxygenation sheet / adhesive layer / display label layer.

3) Mounted form in which the deoxidized sheet is laminated or wrapped with a breathable packaging material. As the breathable packaging material, a packaging material for a conventional oxygen absorber packaging body can be used. For example, a packaging material in which a perforated film is laminated on paper, a water-resistant nonwoven fabric ("Tyvek" manufactured by DuPont,
"Luxa" manufactured by Asahi Kasei Corporation, etc.), various microporous membranes ("Duragard" Celanese, "NF Sheet" Tokuyama Soda)
Co., Ltd., "Nitoflon" manufactured by Nitto Denko Corporation, etc.), and the above-mentioned water-resistant nonwoven fabric, a packaging material obtained by laminating a porous film on a microporous film, and the like, which are further subjected to water resistance and oil resistance treatment. Can also be used.

[0023]

Next, the present invention will be described in more detail with reference to examples.
Note that the present invention is not limited to this embodiment.

Example 1 Production of deoxidized sheet: iron powder (average particle size 70 μm) 100
After adding and mixing 0.5 parts by weight of barium sulfate with respect to parts by weight, a solution obtained by dissolving 2 parts by weight of calcium chloride in 2 parts by weight of water was spray-mixed and dried with hot air to obtain an iron-based oxygen-absorbing composition. . After mixing 100 parts by weight of the iron-based oxygen scavenger composition and 40 parts by weight of high-density polyethylene, the mixture was heated and melted at 190 ° C. and formed into a sheet by an extruder. This sheet is 1
It is stretched 8 times in the longitudinal direction at 10 ° C, and has a 0.5mm thickness
Manufactured. Manufacture of oxygen-absorbing packaging: 30 mm x 30 mm of the resulting oxygen-absorbing sheet
mm size, one side is a 50 mm x 50 mm polyethylene terephthalate / polyethylene film, the other side is 50 mm
It was covered with a packaging material of a water-resistant non-woven fabric (manufactured by Tyvek, DuPont) having a size of 50 mm × 50 mm, and heat-sealed on each of its four sides by 5 mm to prepare a card-type oxygen-absorbing resin package.

The produced oxygen-absorbing sheet package and absorbent cotton containing 5 ml of water are sealed in a gas barrier bag composed of an aluminum / nylon / polyethylene laminated film together with 25 ml of air, and stored in the bag after storage at 35 ° C. for 3 days. The hydrogen and oxygen concentrations were measured.

Example 2 Production of deoxidized sheet: iron powder (average particle size 70 μm) 100
A solution obtained by dissolving 2 parts by weight of calcium chloride in 2 parts by weight of water was spray-mixed with respect to parts by weight, dried with hot air, and then added with 2.5 parts by weight of anhydrous calcium sulfate to obtain an iron-based oxygen-absorbing composition. . After mixing 100 parts by weight of the iron-based oxygen scavenger composition and 40 parts by weight of high-density polyethylene, the mixture was heated and melted at 190 ° C. and formed into a sheet by an extruder. This sheet was stretched 8 times in the longitudinal direction at 110 ° C., and processed into the same form as in Example 1 except that an oxygen deoxygenated sheet having a thickness of 0.5 mm was produced. Created body. The obtained card-type oxygen-absorbing resin package was sealed in a gas barrier bag together with absorbent cotton containing 5 ml of water and 100 ml of air at 25 ° C. 90
After storing for one day, the hydrogen and oxygen concentrations were measured, and the package was opened and the odor was confirmed.

Example 3 Production of deoxidized sheet: iron powder (average particle size 50 μm) 100
A solution prepared by dissolving 1 part by weight of sodium chloride and 1 part by weight of sodium sulfate in 4 parts by weight of hot water was mixed by spraying and dried with hot air to obtain an iron-based oxygen scavenger composition. After mixing 60 parts by weight of the iron-based oxygen scavenger composition and 40 parts by weight of linear low-density polyethylene, the mixture was heated and melted at 150 ° C., and formed into a sheet by an extruder. This sheet was stretched 6 times in the longitudinal direction at 95 ° C., and processed into the same form as in Example 1 except that an oxygen deoxygenated sheet having a thickness of 0.5 mm was produced. Created body. 100 ml of absorbent cotton and air containing 5 ml of water in the obtained card-type deoxygenated resin package.
At the same time, it was sealed in a gas barrier bag, and after storing at 30 ° C. for 10 days, the hydrogen and oxygen concentrations were measured, and then the bag was opened to confirm the odor.

Comparative Example 1 Production of deoxidized sheet: iron powder (average particle size 70 μm) 100
A solution prepared by dissolving 2 parts by weight of calcium chloride in 2 parts by weight of water was spray-coated and dried with hot air to obtain an iron-based oxygen scavenger composition. After mixing 100 parts by weight of the iron-based oxygen absorber composition and 40 parts by weight of high-density polyethylene,
And heat-melted, and formed into a sheet by an extruder. This sheet is stretched 8 times in the machine direction at 110 ° C. to a thickness of 0.5 mm.
Except for producing the oxygen-deoxygenated sheet of Example 1, processing was performed in the same manner as in Example 1, and hydrogen generation and odor were confirmed under the same conditions using the obtained card-type deoxygenated resin package.

Comparative Example 2 Production of deoxidized sheet: iron powder (average particle size 70 μm) 100
A solution prepared by dissolving 2 parts by weight of calcium chloride in 2 parts by weight of water was spray-mixed with 700 parts by weight of powder sulfur added to and mixed with parts by weight, and dried with hot air to obtain an iron-based oxygen scavenger composition. After mixing 100 parts by weight of the iron-based oxygen absorber composition and 40 parts by weight of high-density polyethylene, the mixture was heated and melted at 190 ° C.
The film was formed into a sheet by an extruder. This sheet is 110
The same process as in Example 1 was carried out except that the sheet was stretched eight times in the machine direction at a temperature of 0.5 ° C. to produce a 0.5 mm-thick oxygen deoxygenation sheet.
Using the obtained card-type deoxygenated resin package, hydrogen generation and odor were confirmed under the same conditions.

Comparative Example 3 Production of deoxidized sheet: iron powder (average particle size 70 μm) 100
A solution prepared by dissolving 2 parts by weight of calcium chloride in 2 parts by weight of water with respect to parts by weight was spray-mixed, dried with hot air, and then added with 5 parts by weight of barium sulfate to obtain an iron-based oxygen scavenger composition. After mixing 100 parts by weight of the iron-based oxygen-absorbing composition and 40 parts by weight of high-density polyethylene, the mixture was heated and melted at 190 ° C., and an attempt was made to form a sheet by an extruder. No pressure was obtained, and it was impossible to stably perform continuous film formation.

[0031]

[Table 1]

[0032]

According to the oxygen-absorbing resin composition of the present invention, the generation of hydrogen is suppressed by adding an iron-based oxygen-absorbing agent containing a certain amount of an inorganic sulfate to the polyolefin resin composition, and the generation of off-flavor is reduced. Absent. A deoxidized sheet can be produced from the deoxidized resin composition of the present invention without any problem. INDUSTRIAL APPLICABILITY The oxygen-absorbing sheet of the present invention suppresses generation of hydrogen and does not generate off-flavors, and thus is suitably used for preserving foods.

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Claims (4)

[Claims] 1. A resin composition comprising 15 to 75 parts by weight of a polyolefin resin and 25 to 85 parts by weight of an iron-based oxygen scavenger comprising iron, a metal halide and an inorganic sulfate. The amount of the inorganic sulfate in the agent is,
The weight of sulfur contained in inorganic sulfate is based on the weight of iron
A deoxidized resin composition having a weight ratio of 500 ppm to 5,000 ppm. 2. An oxygen-absorbing resin sheet comprising the oxygen-absorbing resin composition according to claim 1. 3. A method for producing an oxygen-absorbing resin sheet, comprising: extruding the oxygen-absorbing resin composition according to claim 1 after melt-kneading; 4. A process for producing an oxygen-absorbing resin sheet, comprising melt-kneading the oxygen-absorbing resin composition according to claim 1, extruding, forming a sheet, and stretching.