JP2006130716A - Laminate and container using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminate not causing the occurrence of a crack in a titanium dioxide added resin layer due to volumetric expansion, the leakage of content, the occurrence of foreign taste and the like because titanium dioxide having an oxygen defect is used as an oxygen absorbent material. <P>SOLUTION: The titanium dioxide added resin layer having the oxygen defect inside a barrier layer at the time of formation of a container is provided to the laminate for the container composed of at least paper, the barrier layer and a sealant layer. It is especially preferable that the content of titanium dioxide in the titanium dioxide added resin layer having the oxygen defect is 0.5-50 wt.% or the ratio of the oxygen defect of titanium dioxide having the oxygen defect is 0.01-25% of the number of oxygen atoms in titanium dioxide. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a so-called container in which paper, a barrier material, and a heat-sealable sealant material are laminated and further molded by heat sealing.

  More specifically, the present invention provides a container that prevents the contents from being deteriorated by oxygen and aerobic microorganisms, insects, etc., can be stored for a long period of time, and has excellent usability.

  A so-called paper container obtained by laminating paper, a barrier material, and a heat-sealable sealant, and further molded and sealed by heat sealing is widely used mainly as a liquid container. As a shape, there are a brick-shaped so-called brick type, a roof top-shaped gable top type, and a cylindrical paper container. In any case, a heat-sealable resin layer is provided in the innermost layer (and also in the outermost layer as required), a container is formed by heat sealing, the contents are filled, and further sealed by heat sealing.

  Since oxygen causes oxidative deterioration of the contents and the growth of aerobic microorganisms such as mold, these containers are laminated with a barrier material such as aluminum foil, and then inert gas such as nitrogen is added. Fills the head space and tries to remove oxygen. In some cases, a filling method that does not provide a head space by a sealing method called a sub-surface seal is used.

  As an example of a typical configuration, aluminum foil (Al) is used for the barrier layer, polyethylene (PE) is used for the sealant layer, and "polyethylene (PE) / printing / paper / polyethylene (PE) / aluminum" from the outer layer of the container. Foil (Al) / polyethylene (PE) ”. Recently, a barrier material obtained by depositing alumina or silica on a base film such as a polyester film has been used as a barrier material. Further, there may be a case where the dissolved oxygen in the filling itself is removed and filled.

On the other hand, for the purpose of removing 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, or reduced iron as an active ingredient is wrapped in a gas-permeable sachet. Has been. Recently, a quality retainer containing titanium dioxide having oxygen defects as an active ingredient has been proposed. This absorbs oxygen in the container and can suppress the growth of microorganisms by photocatalysis. (Patent Document 1)
Patent documents are as follows.
Japanese Patent Laid-Open No. 11-12115 Japanese Unexamined Patent Publication No. 7-187255

  However, it is impossible to completely block the mixing of oxygen at the time of filling and the ingress of oxygen over time. For example, in a barrier layer such as aluminum foil, pinholes are generated and oxygen enters during container manufacturing, filling and packaging, and transportation. Oxygen also enters from the heat seal portion of the container. Further, industrially, a gas replacement packaging method for removing all the oxygen concentration in the head space of the container has not been developed.

In addition, oxygen scavengers cannot be used because the components are eluted in the liquid. Also, if there is a sachet in the liquid food, it cannot be used because there is a possibility of accidental ingestion.

  Therefore, as a means for removing oxygen that enters or remains inside the container, a container has been proposed in which iron is added to the container resin layer to absorb and remove oxygen in the container (Patent Document 2).

  However, when iron is oxidized, it changes to iron oxide. For this reason, cracks of the added resin layer due to volume expansion may occur, and rust seepage and contents may leak out. In addition, the eluted iron ions may be combined with food ingredients to produce a nasty taste.

  In addition, due to its physical properties, when it is heated in a microwave oven, it sparks. Therefore, foods filled and packaged in an iron-based oxygen absorbent-added container have a drawback that they cannot be heated by a microwave oven.

  Similarly, since the metal detector reacts, there is a disadvantage that it cannot be applied to the metal detector after filling and packaging.

  Similarly, containers using aluminum foil as a barrier layer are not suitable for heating in a microwave oven or using a metal detector.

  The present invention solves the above problems.

  The invention of claim 1 is characterized in that a laminated body for containers comprising at least paper, a barrier layer, and a sealant layer is provided with a titanium dioxide-added resin layer having oxygen defects inside the barrier layer when used as a container. It is related with the laminated body to perform.

  The invention according to claim 2 is characterized in that the titanium dioxide content in the titanium dioxide-added resin layer having oxygen defects is 1 to 100 parts by mass with respect to 100 parts by mass of the thermoplastic resin. It is about.

  The invention of claim 3 is characterized in that the proportion of oxygen defects in titanium dioxide having oxygen defects is 0.01% to 25% of the number of oxygen atoms in titanium dioxide. It is related with the laminated body of.

  The invention according to claim 4 relates to the laminate according to claims 1 to 3, wherein the barrier layer is made of a transparent vapor deposition film.

  The invention according to claim 5 relates to the laminate according to any one of claims 1 to 4, wherein the titanium dioxide having oxygen defects is a crystal form of anatase.

  The invention of claim 6 relates to a container characterized in that at least a part of the container has a heat-sealed portion using the laminate of claims 1 to 5.

  According to the invention of claim 1 and claim 6 corresponding thereto, since titanium dioxide having oxygen defects is used as the oxygen-absorbing material, cracks in the added resin layer due to volume expansion, leakage of contents, and strange taste There is no such thing as the occurrence of

  According to the invention of claim 2 and claim 6 corresponding thereto, it is possible to maintain the physical properties of the container and obtain an oxygen-absorbing container.

  According to the invention of claim 3 and claim 6 corresponding thereto, the oxygen inside the container is efficiently removed by using titanium dioxide having an oxygen defect ratio of 0.01% to 50%. It is possible to absorb.

  According to the invention of claim 4 and claim 6 corresponding thereto, it not only has suitability for microwave ovens and suitability for metal detectors, but also has excellent suitability for incineration at the time of disposal.

  According to the invention of claim 5 and claim 6 corresponding thereto, it is possible to have an antibacterial action by generating active oxygen by light.

  In this case, at least a part of the container does not need to be configured by the laminated body according to any one of claims 1 to 5. For example, only the barrel of the cylindrical container is configured by the laminated body of the present invention. This means that only the seam is heat sealed, and the top and bottom are made of separate materials and connected.

  The laminate for containers composed of at least paper, a barrier layer, and a sealant layer, and the container according to the present invention can be obtained by providing a layer containing oxygen defects inside the container of the barrier layer.

  As a method of providing a layer containing titanium dioxide having oxygen defects, titanium dioxide having oxygen defects is kneaded into the resin layer disposed inside the container of the barrier layer, or the coating agent or adhesive has oxygen defects. Titanium may be dispersed. For example, “polyethylene (PE) / printing / paper / polyethylene (PE) / aluminum foil (Al) / titanium dioxide-kneaded polyethylene (PE) having oxygen defects”, “polyethylene (PE) / printing / paper / Polyethylene (PE) / aluminum foil (Al) / titanium dioxide-kneaded polyethylene (PE) / polyethylene (PE) having oxygen defects ”,“ polyethylene (PE) / printing / paper / polyethylene (PE) / aluminum foil (Al) / Dispersed titanium dioxide with oxygen defects / Adhesive with dispersed titanium dioxide with oxygen defects / Polyethylene (PE), and "Polyethylene (PE) / Printing / Paper / Polyethylene (PE) / Aluminum foil (Al) / Dispersed titanium dioxide with oxygen defects Adhesive / titanium dioxide kneaded polyethylene (PE) / polyethylene (PE) with oxygen defects ” It is.

  In addition, the barrier layer must be at least an oxygen barrier material. In addition to the aluminum foil, the base layer is coated with a transparent vapor deposition film, a base layer or the like, which is coated with a physical vapor deposition method or a chemical vapor deposition method. Coated film in which acrylic material, silica-based material and vinylidene chloride copolymer (PVDC) are coated on the material, for example, ethylene vinyl acetate alcohol copolymer (EVOH) or vinylidene chloride copolymer (PVDC) with low oxygen permeability ) Resin film can be used.

  In particular, transparent vapor-deposited films coated with silica or alumina by vapor deposition do not emit harmful substances during incineration, have no barrier dependency on humidity, and are suitable for microwave ovens and metal detectors. It is preferably used from the above.

The sealant layer may be any material that can be heat-sealed. Polyolefins such as low-density polyethylene and polypropylene, which are usually used as sealant materials, have an oxygen permeability of about 25 μm. Since it is 70,000 to 500,000 (ml / m ² · day · MPa), even if a sealant layer is disposed inside the container of the titanium dioxide-containing layer having oxygen defects, it does not interfere with the oxygen absorption capacity. Absent.

  Titanium dioxide having oxygen defects is obtained by heating ordinary titanium dioxide in an oxygen-free atmosphere or irradiating with ultraviolet rays, and the production method is not particularly limited.

  The titanium dioxide having oxygen defects used in the present invention may be a crystalline form such as rutile or brookite or an amorphous form, more preferably an anatase form. Anatase-type titanium oxide has photocatalytic activity. When a transparent vapor-deposited film or a low-oxygen-permeable resin transparent film is used for the barrier layer, active oxygen species are generated by the light transmitted through the paper, resulting in a bactericidal effect. There is an advantage that a deodorizing effect can be obtained.

  The shape is not particularly limited, and may be granular, spherical, plate-like, columnar, cylindrical, powdery, granular, etc., but has a large surface area and a granular or powdery form having a high oxygen absorption rate. Are more preferred.

  The size of titanium dioxide having oxygen defects used in the present invention is not particularly limited, but is preferably about 10 nm to 10 μm in consideration of dispersibility in a resin or coating agent, photocatalytic activity, and the like.

  The content of titanium dioxide having oxygen defects used in the present invention is preferably 1 to 100 parts by mass with respect to 100 parts by mass of the thermoplastic resin. If it is less than this, it will not be possible to obtain a sufficient oxygen absorption capacity, and if it is more than this, the additive resin layer will become brittle and the strength as a container may not be maintained.

  The proportion of oxygen defects in the titanium dioxide having oxygen defects used in the present invention is preferably that from which 25% of oxygen is released from 0.01% of the number of oxygen atoms in titanium dioxide. If the ratio of oxygen defects is lower than this, it becomes 1 ml or less per 1 mol of titanium dioxide 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.

  Since the laminate according to the present invention has a normal configuration except that a titanium dioxide-added resin layer having oxygen defects is provided on the inner side of the barrier layer when used as a container, it can be manufactured with existing equipment.

  Moreover, since the laminated body by this invention can be shape | molded and filled with the existing equipment, it is economical.

  Using an alumina-deposited polyester film for the barrier layer, from the outer layer, “polyethylene (PE) (1) / printing / paper (2) / polyethylene (PE) (3) / alumina-deposited polyester film (4) / oxygen defects” A laminated body (FIG. 1) having a composition of “polyethylene (PE) (50 μm) (5) / polyethylene (PE) (15 μm) (6)” added with 25 wt% titanium dioxide) was obtained.

  As the titanium dioxide having oxygen defects used, one having a particle diameter of 200 nm from which 10% of oxygen of anatase-type titanium dioxide was released was used.

Furthermore, the obtained laminated body was used and the cylindrical container shown in FIG. 2 was created by the heat seal method. The area in contact with the contents was about 210 cm ² , and the “alumina-deposited polyester film / PE” constituent film was laminated on the joint (14) of the body portion by the heat seal method to protect the end face (15). .
<Test 1>
The obtained container is filled with water (250 ml) from the drinking mouth (16), and the alumina vapor-deposited polyester film / PE-structured film is heat-sealed and sealed (17). 21) was obtained. The head space capacity was about 10 ml. The dissolved oxygen concentration of the filled water was 7.5 ppm.

This was stored at 25 ° C. for 1 week, and the oxygen concentration in the head space was measured using an oxygen concentration meter, and the dissolved oxygen concentration of water was measured using a dissolved oxygen meter. The results are shown in Table 1.
<Test 2>
The resulting container was similarly filled with a beverage and sealed. The head space capacity was about 10 ml.

  As the beverage, orange juice was used, which was sterilized at 98 ° C. for 30 seconds using a plate-type sterilizer in an aseptic environment.

This was stored in a 34 ° C. environment for 3 months, and the oxygen concentration, dissolved oxygen concentration, and amount of reduced ascorbic acid in the headspace were measured. The indophenol method was used to measure the amount of reduced ascorbic acid. Moreover, it evaluated by sensory evaluation. The state of the packaging material was also observed.
<Test 3>
The sample used in Test 1 was heated in a household microwave oven (600 W), and the suitability of the microwave oven was evaluated. The observation results are shown in Table 3.
<Test 4>
The obtained container was similarly filled with physiological saline (250 ml) supplemented with 1,000 cfu / ml of bacteria and sealed.

  As bacteria, Staphylococcus aureus and Escherichia coli were used.

  This was irradiated in a 35 ° C. environment with a fluorescent tube at 1,000 lx, stored for 1 week, and the number of bacteria was measured by a plate method using a standard agar medium.

  The results for Staphylococcus aureus are shown in Table 4, and the results for Escherichia coli are shown in Table 5, respectively.

  The result of Test 1 showed that the container made of the laminate having the titanium dioxide-containing layer having oxygen defects according to the present invention absorbs oxygen in the same manner as the iron-based oxygen absorption container used conventionally. .

  According to the results of Test 2, the container made of the laminate having the titanium dioxide-containing layer having oxygen defects according to the present invention has no occurrence of pinholes due to “rust” found in the iron-based oxygen absorbent, It was shown that it was excellent in preservability. In addition, it was considered that the decrease in the oxygen concentration in the head space and the dissolved oxygen in Comparative Examples 2 and 3 decreased because the oxygen contained in the filling was used for the oxidation of the components.

  As a result of Test 3, the container using the laminate according to the present invention in which the barrier layer is a transparent vapor-deposited film showed suitability for a microwave oven.

  The result of Test 4 showed that the container using the laminate according to the present invention using anatase-type titanium dioxide having oxygen defects has antibacterial performance when irradiated with light.

Using an aluminum foil with a thickness of 9 μm for the barrier layer, from the outer layer, “polyethylene (PE) / printing / paper / polyethylene (PE) / aluminum foil (Al) / polyethylene (PE) added with 25% by weight of titanium dioxide having oxygen defects” (50 μm) / polyethylene (PE) (15 μm) ”laminate was obtained.

  The used titanium dioxide having oxygen defects has a particle diameter of 200 nm from which 10% of oxygen of anatase titanium dioxide has been released.

  Other than that, a cylindrical container was produced in the same manner as in Example 1.

<Comparative Example 1>
Using an alumina-deposited polyester film for the barrier layer, from the outer layer, “polyethylene (PE) / printing / paper / polyethylene (PE) / alumina-deposited polyester film / polyethylene (PE) added with 10% by weight of reduced iron (50 μm) / polyethylene” A (PE) (15 μm) ”laminate was obtained.

  The reduced iron used is reagent grade iron powder. Moreover, what added 1 weight% of sodium chloride as a reaction accelerator was used for the polyethylene layer 10 weight% reduction iron addition.

  Other than that, a cylindrical container was produced in the same manner as in Example 1.

<Comparative example 2>
Using an aluminum foil with a thickness of 9 μm for the barrier layer, a laminate having a structure of “polyethylene (PE) / printing / paper / polyethylene (PE) / aluminum foil (Al) / polyethylene (PE) (65 μm)” is obtained from the outer layer. It was.

  Other than that, a cylindrical container was produced in the same manner as in Example 1.

<Comparative Example 3>
Using an alumina-deposited polyester film for the barrier layer, a laminate having a structure of “polyethylene (PE) / printing / paper / polyethylene (PE) / alumina-deposited polyester film / polyethylene (PE) (65 μm)” was obtained from the outer layer. .

  Other than that, a cylindrical container was produced in the same manner as in Example 1.

  INDUSTRIAL APPLICABILITY The present invention is used in the technical field related to so-called containers that are formed by laminating paper, a barrier material, and a heat-sealable sealant, and further forming by heat sealing.

FIG. 1 is a partially enlarged sectional view showing an example of a laminate according to the present invention. FIG. 2 is a partially broken side view, a plan view, and a bottom view showing an example of the container according to the present invention. FIG. 3 is a plan view after filling and sealing the container of FIG. 2 according to the present invention. 4 is a perspective view of the container of FIG. 3 according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 3, 6: Polyethylene layer 2: Paper 4: Barrier layer 5: Titanium dioxide addition resin layer having an oxygen defect 14: Joint part of trunk | drum 15: "Alumina vapor deposition polyester film / PE" Constituent film 16: Drinking mouth 17 : Alumina-deposited polyester film / PE film

Claims (6)

  A laminate comprising a container laminate comprising at least paper, a barrier layer, and a sealant layer, and a titanium dioxide-added resin layer having oxygen defects inside the barrier layer when the container is formed.   The laminate according to claim 1, wherein the titanium dioxide content in the titanium dioxide-added resin layer having oxygen defects is 1 to 100 parts by mass with respect to 100 parts by mass of the thermoplastic resin.   The laminate according to claim 1 or 2, wherein the proportion of oxygen defects in titanium dioxide having oxygen defects is 0.01% to 25% of the number of oxygen atoms in titanium dioxide.   4. The laminate according to claim 1, wherein the barrier layer is made of a transparent vapor deposition film.   The laminate according to any one of claims 1 to 4, wherein the titanium dioxide having oxygen defects is a crystal form of anatase.   A container having a heat-sealed portion using at least a part of the container using the laminate according to claim 1.

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