JP2885079B2 - Humidity control laminated bag - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a humidity control laminated bag which loses its practical value when it absorbs moisture, and is effective for packaging so-called moisture-insensitive foods.

[0002]

2. Description of the Related Art Conventionally, it has been widely practiced to enclose a desiccant in the packaging of an object to be humid, but the problem of erroneously eating the desiccant still remains. Is the current situation. Moreover, since the desiccant is used as a package, it is present as a dot in the container, so it is difficult to uniformly dehumidify the entire interior of the container. . Also, even if the moisture in the container is dehumidified with a desiccant, the moisture that passes through the container and does not block the moisture will increase over time, even if many desiccants are used. Can not. Also,
Films with an oxygen barrier layer laminated are widely used because the inclusions that oxygen penetrates and penetrates the bag are deteriorated, but ethylene-vinyl alcohol copolymer, a typical oxygen barrier material, is highly water sensitive. In addition, when water is contained, the oxygen barrier property is lost. Therefore, it has been proposed to arrange a hygroscopic layer in close contact with such an oxygen barrier layer which dislikes moisture and protect the oxygen barrier layer from water. For example, Japanese Patent Publication No. 61-34392 discloses a laminate of a polyolefin base film and an ethylene-vinyl alcohol film, and 20% by weight of silica gel in an adhesive for bonding the two.
It is described that the degree is added. Japanese Patent Application Laid-Open No.
Almost the same matters are described in JP-A-49750. In addition, Japanese Patent Application Laid-Open No. 64-384 discloses a method in which a superabsorbent resin film layer is laminated to contain water, and the water is used to react a substance contained in the laminated film to lower the temperature.
No. 60 is proposed. Further, a desiccant formed by kneading a desiccant into a synthetic resin to form a sheet is also disclosed in Japanese Patent Application Laid-Open No. 2-1073.
No. 1 discloses that lamination with a polyethylene film is used as an inner lining of a packaging can. However, none of the proposals describes that in order to adjust the humidity in the bag, moisture from the outside is shut off, and the moisture in the bag is removed by a moisture absorbent existing in the laminated film.

[0003]

SUMMARY OF THE INVENTION According to the present invention, the moisture absorption in a bag is fundamentally prevented by the moisture absorption in the bag by the film constituting the bag, and the moisture in the bag is eliminated by performing the dehumidification on the entire surface of the bag. And maintain the optimal temporal humidity stability over time by blocking the intrusion of moisture from the outside.

[0004]

Means for Solving the Problems The present invention provides a method comprising: sandwiching a heat absorbing film layer by co-extruding a moisture absorbing layer composed of a blend of a polyester resin layer, an aluminum foil, and a polyolefin and a zeolite; A bag formed by laminating an inner surface material layer and a polyester resin layer as an outermost layer and an inner surface material layer as an innermost layer, wherein the innermost heat-sealable resin layer ( The thickness of the sealant layer is smaller than the thickness of the moisture-absorbing layer, the average particle size of the zeolite in the moisture-absorbing layer is 5 to 70 μm, and the blending ratio of the zeolite is 0.1 to 50% by weight. 2. The heat-sealing film layer is made of low-density polyethylene, linear low-density polyethylene, ethylene-vinyl oxide copolymer, ethylene-acrylic acid copolymer. The humidity-controlling laminated bag according to item 1, which is one selected from a polymer, an ethylene-methacrylic acid copolymer, an ethylene-acrylate copolymer, and an ionomer. "

[0005]

According to the present invention, the use of a special laminated film provides a special humidity control effect. The humidity control laminated bag of the present invention is provided with a polyester resin (hereinafter referred to as PET) layer as the outermost layer. The polyester resin layer is suitable for the outermost layer because it has good gas barrier properties, excellent printability, and high strength.

Next to the polyester resin layer, aluminum (hereinafter A)
L). The AL foil has a good gas barrier property, has an action of blocking the passage of water vapor, and prevents external moisture from entering the bag.

A moisture absorbing layer is provided inside the AL foil. The moisture absorbing layer is formed of a blend of polyolefin and zeolite . The polyolefin low density polyethylene (L D
PE), linear low density polyethylene having (LLDP E), ethyl
Styrene-acrylic acid copolymer ( EAA ) , ethylene -acrylic acid
Lylic acid ester copolymer ( EAE ) , ionomer (I), ethylene-methacrylic acid copolymer (EMAA)
Etc. are used. As the hygroscopic agent, zeolite is most preferable because of its hygroscopicity and film properties.

The average particle size of the zeolite is preferably 5 to 70 μm, and if it is 5 μm or less, secondary particles having a large diameter tend to be formed due to agglomeration due to small particle size, the surface area becomes small, and the hygroscopicity becomes poor. If it is 70 μm or more, the surface area becomes small and the hygroscopic action becomes small, which is not preferable. Also Zeola
The amount of site is a 0.1 to 50 wt%, less hygroscopic effect is 0.1 wt% or less, since the foam to facilitate also the roughness of the film by moisture absorption is too large increases in 50 wt% or more Not preferred.

The moisture-absorbing layer is not the film containing zeolite as it is, but is disposed on the innermost layer as an inner surface material layer of a sandwich structure in which both surfaces are sandwiched and co-extruded with a heat-sealing film layer. Thus adjustment of the hygroscopic degree of the sandwich structure by coextrusion and zeolite
It covers the rough surface of the film by site formulation, prior to use
To stabilize production without losing moisture absorption capacity
It is. Therefore, the inner surface material is a heat-sealable resin layer /
It has a structure of a moisture absorbing layer / heat sealing resin layer . In this way was to place the human Toshiru of the film layer to the innermost surface, in addition that can be sealed and heat-sealed at the time of packaging, this film layer is because there is no danger to the touch to be packaged because there is no toxicity. The heat-sealable film layer in the present invention may be a low-density polyethylene (LDP).
E) Linear low density polyethylene (LLDPE), ethylene- vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-acrylate copolymer (EAE), ionomer, ethylene-meta A film layer of a polymer selected from acrylic acid copolymer (EMAA) is used. These polymers are suitable for the innermost layer of bags because they are non-toxic and have excellent heat sealing properties.

The basic structure of the laminated film forming the temperature-controlled laminated bag of the present invention is 12 μPET /
7 μAL / 70 μ coextruded layer and 12 μPET / 15 μLDPE / 7 with LDPE placed next to PET
The μAL / 70μ coextruded layer also shows good performance. In the laminated bag of the present invention, since the AL foil layer is disposed outside the moisture-absorbing layer, external moisture does not enter the bag. Therefore, the moisture-absorbing layer exclusively absorbs the moisture in the bag, and thus has a long hygroscopic property. Because it is sustained, the shelf life of foods and the like is significantly longer than conventional packaging. Further, since the film itself has a moisture absorbing action, there is no problem of accidental ingestion of the desiccant, and there is no discomfort when the desiccant is mixed in the food or the like.

[0011]

Next, the present invention will be described in detail with reference to examples.

Example 1 A bag was formed using a laminated film in which 12 μm PET was placed on the outermost layer, followed by 7 μm AL foil, and then 70 μm co-extruded layer. The co-extruded layer is 10μLDPE / 50μ
It is a zeolite layer / 10 μLDPE, and the zeolite layer is a layer in which zeolite having a particle size of 10 μ is blended with 1% by weight LDPE.

[0013] The configuration of Example 2-5 laminate film No. shown in Table 1 2 , 9, 10,
A laminated bag was made in the same manner as in Example 1 except that the bag was 11.

Comparative Examples 1 to 7 3-8 and 12
A laminated bag was made in the same manner as in Example 1 except for the above. Table 1 shows the film configuration and performance.

[0015]

[Table 1]

(Note) O to X in the column of evaluation have the following meanings. : Good △: inferior ×: bad Explanation of Comparative Example 3: The average particle size is large, the surface area to be adsorbed is small, and the hygroscopicity is deteriorated. No. 4: The average particle size is small and the cohesive force acts, resulting in a large particle size. No. 5: The moisture absorption layer is thin and the moisture absorption performance is small. No. 6: Since the sealant layer is thick and has low moisture permeability, the hygroscopic ability is inferior. No. 7: Moisture permeation from outside is large because no aluminum foil is laminated. No. No. 8; 12: Particle size because silica gel is used as a hygroscopic agent
But the film properties are poor. I in the table is an abbreviation for ionomer.

[0017]

As described above, the humidity-controlling laminated bag of the present invention maintains the moisture absorption in the bag for a long time, does not mix the desiccant into the package, and has no problems such as accidental eating and discomfort.

Claims (2)

(57) [Claims] 1. A method comprising: a. A polyester resin layer; b. Aluminum foil; c. An inner surface material layer in which a moisture absorbing layer composed of a blend of polyolefin and zeolite is laminated in the form of a sandwich by co-extrusion with a heat-sealing film layer, and a layer formed by laminating a polyester resin layer as the outermost layer and an inner surface material layer as the innermost layer The thickness of the innermost heat-sealable resin layer (sealant layer) constituting the inner surface material layer is thinner than the thickness of the moisture absorbing layer, and the average particle size of zeolite in the moisture absorbing layer is 5 to 5. A humidity-controlling laminated bag having a thickness of 70 µm and a blending ratio of zeolite of 0.1 to 50% by weight. 2. The heat-sealing film layer is made of low-density polyethylene, linear low-density polyethylene, ethylene-vinyl oxide copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-acrylic acid. It is a kind selected from ester copolymers and ionomers.
The humidity control laminated bag according to claim 1.