JP2009132441A - Packaging laminated material and packaging container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a packaging laminated material and a container which prevent the deterioration of quality and taste of contents due to the oxygen deterioration without receiving the effect of an atmosphere condition, exert an oxygen absorbing capability at a necessary timing, and show less deterioration in oxygen absorbing capability in a material manufacturing process. <P>SOLUTION: The packaging laminated material includes a deoxidation layer containingan deoxidation composition formed of a rare earth metal oxide having an oxygen vacancy, or preferably, a cerium oxide of 0.05 pts.wt. to 10 pts.wt., and a water- or moisture-degraded oxygen barrier resin of 100 pts.wt. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a packaging laminate material and container using a resin composition having oxygen absorption ability, and more specifically, prevents deterioration and taste deterioration due to oxygen deterioration of contents, and exhibits oxygen absorption ability at a necessary timing. The present invention relates to a packaging laminate material and a container that can be reduced and have little deterioration in oxygen absorption capacity in the process of producing the packaging laminate material.

For packaging containers for milk, juice, sake, shochu, mineral water and other beverages, for example, a web-like packaging material with a crease line attached to a laminate consisting of a paper layer / plastic layer is sealed by a longitudinal vertical line seal. Molded into a tube shape, filled with the contents in the tube-shaped packaging material, applied with a horizontal line seal in the transverse direction of the tube-shaped packaging material, first molded into a pillow-shaped primary shape, and the packaging material was strip-shaped In this case, it is cut into individual pieces at regular intervals, folded along a crease line, and formed into a final shape. The final shapes include brick shapes (parallelepipeds), hexagonal column shapes, octagonal column shapes, tetrahedral shapes, and the like.

In a gable top (roof type) paper packaging container, paper packaging material is cut into a predetermined shape, blanks sealed in the vertical direction of the container are obtained, and after the bottom of the blanks is sealed in the filling machine, milk is introduced from the top opening. Filled with juice or other beverage filling and sealed at the top. These packaging materials have the appearance design of the packaging container product printed on the surface thereof.

Packaging materials used for packaging container products are low density polyethylene (LDPE) / printing ink layer / paper layer / LDPE / aluminum foil (as gas barrier layer) / LDPE / LDPE, LDPE / printing ink layer / paper Layer / LDPE / LDPE, printing ink layer / LDPE / paper layer / LDPE / LDPE, LDPE / printing ink layer / paper layer / LDPE / aluminum foil / polyester (PET), etc. are known and are actually It is widely used.

In general, the above-mentioned packaging laminate is obtained by carrying a base paper roll of a paper layer into a printing machine, printing on the base paper surface, winding the printed paper again into a roll, feeding it to an extrusion laminator, and melting from an extrusion die. When a polyolefin (for example, LDPE or the like) is extruded onto the base paper surface and there is a gas barrier layer (aluminum foil or the like) in addition to the base paper, it is manufactured by extruding the molten polyolefin between the gas barrier layer and applying a laminate coating. When laminating the gas barrier layers as described above or adding other functional layers, instead of laminating all the layers at once, prepare a partial laminate (semi-material) separately. Then, it is formed into a roll shape, and these partial laminates are further laminated to obtain a final laminate.

Each layer of the packaging laminate has a function and a function. The paper layer assembled in the packaging container is provided with a plastic coating for liquid tightness on both sides of the paper layer to effectively protect the liquid absorbent fibrous paper layer from penetration by moisture. These laminated outer layers usually impart excellent heat sealability to the packaging material and, as mentioned above, consist of a thermoplastic material such as low density polyethylene.

A packaging laminate material consisting only of paper and a thermoplastic inner and outer layer lacks mechanical strength and is inferior in gas barrier properties, particularly oxygen gas, from the outside of the container. For example, when the liquid food is citrus fruit juice or the like and stored at room temperature for a long period of time, oxygen barrier properties are required in addition to aroma retaining properties such as fragrances and flavors. This liquid food penetrates oxygen through the carton walls and therefore loses their nutritional value. It is common to add a gas barrier layer to the laminate material to reduce oxygen penetration into the carton and minimize degradation of nutrients such as vitamin C.

  As described above, in order to maintain the quality of the content food, it is possible to prevent the fragrance, flavor, etc. of the content product from being transmitted to the outside through the packaging material, or the fragrance, flavor, etc. Gas that interferes with the quality of the contained product, preventing it from being absorbed by the packaging material that comes into contact with it, or preventing odors from oozing out of the packaged material into the contained product and inhibiting its fragrance, flavor, etc. The packaging material is required to have a gas barrier property that (such as oxygen gas) permeates the laminated material container wall of the packaging container and protects the contents product, and a packaging material having sufficient aroma retention and gas barrier properties is preferable.

Examples of the gas barrier material that imparts gas barrier properties to the packaging material include aluminum foil, EVOH (saponified ethylene-vinyl acetate copolymer, ethylene vinyl alcohol), PVOH (polyvinyl alcohol), and an inorganic oxide vapor deposition layer. Materials with excellent oxygen gas barrier properties are known.
In order to impart barrier properties including aroma retention to the packaging material or film, polyamide, so-called nylon is laminated on the packaging material or film.

In order to remove oxygen inside a sealed container, a so-called oxygen scavenger is used, in which a drug containing an oxidizable substance such as ascorbic acid, gallic acid, and reduced iron as an active ingredient is packaged in a gas-permeable sachet. Yes. In addition, a container has been proposed in which ascorbic acid or iron is added to the container resin layer to absorb and remove oxygen in the container (Patent Documents 1 and 3). A quality maintaining agent containing titanium dioxide having oxygen defects as an active ingredient has been proposed (Patent Document 2).
Japanese Unexamined Patent Publication No. 7-187255 Japanese Patent Laid-Open No. 11-12115 JP-A-6-190960

Iron-based oxygen absorbers may be heated by microwaves in microwave ovens, may not be compatible with microwave ovens, and may react with metal detectors for foreign matter inspection, and oxygen absorbers such as ascorbic acid Moisture is required to absorb oxygen, and the oxygen absorption capacity may be lowered by heat treatment such as retort treatment or heating in a blending step with a resin. Also, if the timing at which the packaging material or container is manufactured differs from the timing at which oxygen absorption should be performed (the timing at which the container is filled with the contents), for example, it is stored in the warehouse after the oxygen-absorbing packaging material is manufactured. In the case where the container is molded and filled with the contents, the oxygen absorption capacity may decrease during that time.

In this invention, the above inconveniences are eliminated, the deterioration and taste deterioration due to oxygen deterioration of the contents are not affected by atmospheric conditions, the oxygen absorption ability can be exhibited at the necessary timing, and in the material manufacturing process Provided are a laminated material for packaging and a container with little deterioration in oxygen absorption capacity.

The packaging laminated material of the present invention includes a deoxidation composition comprising 0.05 to 10 parts by weight of a rare earth metal oxide having oxygen defects and 100 parts by weight of moisture or water-degradable oxygen barrier resin. It has an oxygen layer.

In a preferred embodiment of the invention, the rare earth metal oxide is cerium oxide.

In a preferred embodiment of the present invention, the oxygen barrier resin is a partially / completely saponified product of an ethylene-vinyl acetate copolymer.

In a preferred embodiment of the present invention, the deoxidation layer has a sea-island structure of a water-permeable thermoplastic resin matrix and a deoxygenation composition wrapped in the matrix.

The packaging container for aqueous liquid according to the present invention includes a deoxygenating composition comprising 0.05 to 10 parts by weight of a rare earth metal oxide having oxygen defects and 100 parts by weight of moisture or water-degradable oxygen barrier resin. It has the innermost layer of the deoxidation layer.

In a container according to a preferred embodiment of the present invention, the deoxidation composition comprises 0.1 to 5 parts by weight of cerium oxide having oxygen defects and 100 parts by weight of a saponified ethylene-vinyl acetate copolymer.

The present invention having the above-described configuration functions and functions as follows.
The packaging laminate material of the present invention comprises a rare earth metal oxide having oxygen defects, and a preferred embodiment comprises 0.05 to 10 parts by weight of cerium oxide and 100 parts by weight of moisture or water-degradable oxygen barrier resin. It has a deoxidation layer containing a deoxidation composition.
A cerium oxide oxygen scavenger with oxygen defects is prepared according to the following chemical formula and exhibits an oxygen absorbing function:
Reduction with hydrogen results in cerium oxide with oxygen deficiency.
CeO ₂ + xH ₂ → CeO _2−x + xH ₂ O (↑)
This is enclosed in a package to absorb oxygen inside the package.
CeO _2-x + x / 2O ₂ → CeO ₂

On the other hand, the moisture or water-degradable oxygen barrier resin is more abundant than the rare earth metal oxide. Therefore, in the deoxygenated composition, the rare earth metal oxide is covered, and oxygen reaches the rare earth metal oxide. Without its oxygen absorption ability. The gas barrier performance of the oxygen barrier resin in this invention is deteriorated by moisture or water. When the deoxygenated composition comes into contact with moisture (water content), that is, when the container is filled with the content, the oxygen barrier resin has a reduced gas barrier property, and oxygen reaches the rare earth metal oxide. Exhibits oxygen absorption ability. Oxygen absorption ability can be exhibited at the required timing.

In a preferred embodiment of the invention, the rare earth metal oxide is cerium oxide.
Unlike iron, ascorbic acid, and the like, cerium oxide is not affected by atmospheric conditions and can prevent deterioration due to oxygen deterioration of the contents and taste reduction. In addition, unlike organic substances such as ascorbic acid, it is resistant to heat and has little deterioration in oxygen absorption capacity during the material production process.

In a preferred embodiment of the present invention, the oxygen barrier resin is a partially / completely saponified product of an ethylene-vinyl acetate copolymer.
EVOH significantly deteriorates its gas barrier property due to moisture or water, and when the contents are filled in the container, it lowers the gas barrier property and allows oxygen to reach the rare earth metal oxide to exert its oxygen absorbing ability. Demonstrate the ability to absorb oxygen when needed.

In a preferred embodiment of the present invention, the deoxidation layer has a sea-island structure of a water-permeable thermoplastic resin matrix and a deoxygenation composition wrapped in the matrix.
Oxygen barrier resin is more abundant than rare earth metal oxides, and therefore, in the deoxygenated composition, it covers the rare earth metal oxide, and oxygen does not reach the rare earth metal oxide and exhibits its oxygen absorption capacity. Not.

The packaging container for aqueous liquid according to the present invention comprises 0.05 to 10 parts by weight, preferably 0.1 to 5 parts by weight of a rare earth metal oxide having an oxygen defect, and a moisture or water-degradable oxygen barrier. It has the innermost layer of the deoxidation layer containing the deoxygenation composition which consists of 100 weight part of resin.
It is possible to prevent deterioration and taste deterioration due to oxygen deterioration of the contents without being affected by atmospheric conditions, to exhibit oxygen absorption ability at the necessary timing, and to reduce deterioration of oxygen absorption ability during the material manufacturing process. it can.

Hereinafter, embodiments of the present invention will be described in detail.
The rare earth metal oxide having oxygen defects in the present invention is obtained by heating in an oxygen-free atmosphere or irradiating with ultraviolet rays, and the production method is not particularly limited.

An example of rare earth metal oxide having oxygen defects is cerium oxide. In addition to rare earth metal oxides, titanium dioxide, zinc oxide, iron oxide, and the like are also included. In the case of titanium dioxide, crystal systems such as anatase type, rutile type and brookite type, wurtzite type in the case of zinc oxide, and crystal systems such as lanthanum oxide type and meteorite type in the case of cerium oxide.

The shape may be, for example, granular, spherical, plate-like, columnar, cylindrical, powdery, granular or the like, but is more preferably granular or powdery having a large surface area and a high oxygen absorption rate. In consideration of the dispersibility in the resin, the thickness is preferably about 10 nm to 10 μm.
The content of the rare earth metal oxide having oxygen defects is 0.05 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on the resin.
If it is less than this, sufficient oxygen absorption ability cannot be obtained, and if it is more than this, the added resin layer becomes brittle and the strength as a container may not be maintained. Further, the proportion of oxygen defects in the inorganic compound that forms oxygen defects is preferably such that oxygen is removed from 0.01% to 25% of the number of oxygen atoms in the compound. If the ratio of oxygen defects is lower than this, it becomes 1 ml or less per 1 mol of the compound and sufficient oxygen absorption capacity cannot be obtained, and if it is larger than this, a phenomenon that the oxygen absorption capacity decreases is not preferable.

Examples of the oxygen barrier resin containing the compound subjected to the reduction treatment include EVOH (ethylene vinyl alcohol), PVOH (polyvinyl alcohol), a condensation polymer (nylon-MXD6) of metaxylenediamine and adipic acid, or a blend polymer thereof. .

As a method for producing these resin compositions having oxygen absorbing ability, various predetermined blending amounts of materials set according to the final product molding method and the required oxygen absorbing ability are used, such as a ribbon mixer, a tumbler mixer, a Henschel mixer, etc. Using dry blending or blending a predetermined amount using each feeder pre-installed in a kneader, using a kneader such as a single screw extruder, twin screw extruder, or Banbury mixer And kneaded.

As a molding method of the resin composition having the oxygen absorbing ability obtained above, there is extrusion lamination molding and the like, which can be a single film or a multilayer body. It is also possible to obtain a laminate from the obtained film by dry lamination, wet lamination, or non-solvent lamination.
In addition to the deoxygenated composition, the deoxygenated layer containing the deoxygenated composition can be added and mixed with various resins and compounds depending on the application.
For example, in the case of the innermost layer, low density polyethylene by a high pressure method, polyethylene obtained by using a metallocene catalyst, and the like can be blended to form an innermost layer that can be heat sealed, and the number of layers can be reduced.

Examples will be described below.
A deoxygenated composition was prepared by dry blending cerium oxide having oxygen deficiency when reduced with hydrogen with ethylene-vinyl acetate copolymer saponified product (EVOH) with a kneader.
The compounding ratio consists of 1 part by weight of cerium oxide having oxygen defects and 100 parts by weight of a saponified ethylene-vinyl acetate copolymer.

[Test example]
The above deoxygenated composition corresponding to a volume of 200 ml is put in a pouch with a small amount of water, and the oxygen concentration in the upper part of the pouch is measured in a storage period of 0 days, 10 days, 100 days, and 200 days in an atmosphere of 23 ° C. did.
As a result, the oxygen concentrations (index,%) were 100%, 99%, 96%, and 95%, respectively. From this result, it can be seen that when the deoxygenated composition comes into contact with moisture, the gas barrier property of the oxygen barrier resin is lowered, and oxygen reaches the rare earth metal oxide and exhibits its oxygen absorbing ability.

[Reference example]
As a reference example, evaluation was performed in the same manner as in the above test example except that a small amount of water was not added to the pouch.
As a result, the oxygen concentration (index,%) was 100%, 100%, 99%, and 99%, respectively. From this result, it can be seen that the deoxygenated composition maintained the oxygen barrier property, oxygen did not reach the rare earth metal oxide, and the oxygen absorbing ability could not be exhibited.

In addition, this invention is not limited to this embodiment, It can change variously based on the meaning of this invention, and does not exclude them from the scope of the present invention.

The present invention can be applied to the production of laminated materials for packaging foods and the like.

Claims (6)

It has a deoxygenation layer containing a deoxygenation composition consisting of 0.05 to 10 parts by weight of a rare earth metal oxide having oxygen defects and 100 parts by weight of moisture or water-degradable oxygen barrier resin. Laminated material for packaging. The laminated material for packaging according to claim 1, wherein the rare earth metal oxide is cerium oxide. The packaging laminate material according to claim 1, wherein the oxygen barrier resin is a part / completely saponified product of an ethylene-vinyl acetate copolymer. The laminated material for packaging according to claim 1, wherein the deoxygenated layer has a sea-island structure of a water-permeable thermoplastic resin matrix and the deoxygenated composition wrapped in the matrix. It has an innermost layer of a deoxidation layer containing a deoxidation composition comprising 0.05 to 10 parts by weight of a rare earth metal oxide having oxygen defects and 100 parts by weight of moisture or water-degradable oxygen barrier resin. A packaging container for aqueous liquids. The packaging container according to claim 5, wherein the deoxygenated composition comprises 0.1 to 5 parts by weight of cerium oxide having oxygen defects and 100 parts by weight of a saponified ethylene-vinyl acetate copolymer.