JP2001163373A - One-side absorption type deoxidation multi-layer body - Google Patents

Abstract

(57) [Problem] To provide a one-sided absorption type deoxidized multilayer body having a strong bonding force between layers. An oxygen-absorbing layer (C layer) made of a thermoplastic resin containing a deoxygenating composition, and a concealing layer made of a thermoplastic resin containing a poorly water-soluble inorganic filler on one side of the C layer. (B layer) and a heat seal layer (A layer) made of an oxygen-permeable thermoplastic resin, and the other side of the C layer is made of a nonporous thermoplastic resin to which a rubber-based polymer is added. A buffer layer (D layer) and a barrier layer (E
Layer) arranged on one side, and a single-sided absorption type deoxidized multilayer body. [Effect] The interlayer strength between the deoxidized layer and the barrier layer is large.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a film or sheet having a deoxidizing function. More specifically, food,
Single-sided absorption deoxygenated multilayer body used to construct a deoxidizer or deoxygenation container with the purpose of preventing oxidation of various products that are easily affected by oxygen, such as pharmaceuticals and metal products. About.

[0002]

2. Description of the Related Art Food, pharmaceuticals, and metal products
For the purpose of preventing the oxidation of various products which are easily deteriorated under the influence of oxygen, a deoxidizer for removing oxygen has been conventionally used. The form initially developed as the oxygen absorber and still in use today is one in which a granular or powdered oxygen-absorbing composition is packed in a small pouch. In order to improve this, a film or sheet in which a deoxidizing composition is fixed has been considered as a safe deoxygenating body which is easier to handle and has a wider application range and does not cause problems such as accidental eating.

[0003] In order to form a film or sheet, it is convenient to use a thermoplastic resin as a matrix component to form a composite with a granular or powdery deoxidizing composition. However, if the composite film or sheet is used as it is, there is a risk that the content of the oxygen-absorbing composition may be contaminated by the oxygen-absorbing composition due to the contact between the oxygen-absorbing body and the content, particularly the contact with a liquid. As a countermeasure, it is sufficient to cover this single-layer oxygen-absorbing layer with another shielding layer or a shielding package, but in order to take advantage of the characteristics of the film or sheet, the oxygen-absorbing layer must be covered with another shielding layer. Is ideally configured to be tightly covered.
No. 2941 and the like. Furthermore, if the oxygen-absorbing layer is made porous at the time of stretching and has a multilayer structure in which the upper surface is protected by a non-porous layer, the oxygen-absorbing rate is high, and an oxygen-absorbing film or sheet is produced without exposure or elution of the oxygen absorber. What can be done is shown in Japanese Patent Application Laid-Open Nos. 9-234811 and 10-264279.

In such a deoxidizing film or sheet, a low oxygen permeable barrier layer for preventing invasion of oxygen outside the container is generally bonded or fused to the opposite side of the deoxidizing layer. However, there is a problem that the adhesion between the oxygen-absorbing layer and the barrier layer is poor due to the oxygen-absorbing composition added to the oxygen-absorbing layer. To solve this problem, refer to
Japanese Patent Application Laid-Open No. 234842/1990 and Japanese Patent Application Laid-Open No. 9-40024 propose that a smoothing resin layer is provided between a deoxygenated laminate and a barrier layer. In particular, in the case of a film or sheet in which the oxygen-absorbing layer is made porous, the unevenness of the oxygen-absorbing layer is significantly larger than that in which the oxygen-absorbing layer is not made porous, and there is a problem that it is difficult to improve the adhesiveness by merely providing a thermoplastic resin layer. Japanese Patent Application Laid-Open No. 9-234811 discloses a method in which a thermoplastic resin layer called a buffer layer is provided between a porous deoxygenation layer and a barrier layer. However, in these methods, the adhesive strength between the deoxidizing layer and the barrier layer may be insufficient, and in order to obtain high adhesive strength, it is necessary to increase the thickness of the smoothing resin layer or the buffer layer. There are cases. In particular, this problem was remarkable in a film or sheet in which the deoxidized layer was made porous. The problem to be solved by the present invention is to provide a single-sided absorption type oxygen-absorbing multilayer body in which the adhesion between the oxygen-absorbing layer and the barrier layer is strong.

[0005]

Means for Solving the Problems The inventors provided a buffer layer made of a thermoplastic resin between a deoxygenation layer and a barrier layer,
It has been found that the above problem can be solved by adding a rubber additive to the buffer layer, and the present invention has been completed. That is, the single-sided absorption type oxygen-absorbing film or sheet of the present invention is provided with an oxygen-permeable resin layer (A layer) on one side of a resin layer (C layer) containing the oxygen-absorbing composition. On the other side of the layer, a non-porous buffer layer (D layer) and a barrier layer with low oxygen permeability (E layer) are arranged, and in order to improve the adhesion between the E layer and the D layer, It is characterized in that a rubber-based additive is added to the layer. If necessary, a concealing layer (B layer) containing a poorly water-soluble inorganic filler may be provided between the C layer and the A layer,
Further, the C layer, the B layer, or both layers may be made porous.

The heat seal layer (layer A) is a layer located on the inner surface side of the container and forming a deoxidizing container together with an adjacent layer containing another heat sealable resin as a matrix component. To increase the oxygen absorption rate, the oxygen permeability coefficient should be 1 × 10
^-13 [cm ³ · cm / cm ² · sec · Pa] or more, and 1 × 10 ^-12
[Cm ³ · cm / cm ² · sec · Pa] or more is preferable.

The resin constituting the heat seal layer may be not only a polymer polymerized from a single monomer species but also a mixture of various copolymers and resins, and a non-polar or low-polar polymer is preferable. Further, as long as the oxygen permeability of the entire heat seal layer satisfies the above range, the heat seal layer itself may be composed of a plurality of layers. The heat seal layer is preferably non-porous because heat seal strength can be kept high. In addition, for the heat seal layer, it is preferable to use the same resin as the matrix component of the adjacent layer, and when different resins are used, they are compatible to the extent that they can be thermally fused. Thermoplastic resins are preferred.

Examples of specific resins used for the heat seal layer include ethylene, propylene, 1-butene,
-Homopolymers and copolymers of olefins such as -methyl-1-pentene, ethylene-vinyl acetate copolymer, polybutadiene, polyisoprene, styrene-butadiene copolymers and hydrogenated products thereof, and various silicone resins. And modified products, grafts, and mixtures thereof. The maximum value of the thickness of the heat seal layer is determined by the required performance of the object to be deoxidized represented by the oxygen permeability and the oxygen permeability coefficient of the resin. However, it can be manufactured stably so that pinholes etc. do not occur,
In addition, if it is ensured that pinholes and tears do not occur even in contact with the contents in normal use, it is desirable that the thickness be as thin as possible than the maximum value.
About 50 μm is preferable.

As the oxygen-absorbing composition used in the oxygen-absorbing layer (C layer), known oxygen-absorbing compositions can be used. Among them, metal powders such as iron powder, aluminum powder and silicon powder, ferrous salts, etc. Of oxygen or phenols such as inorganic salts, ascorbic acid and salts thereof, catechol and glycerin are preferred. The maximum particle diameter of the oxygen-absorbing composition may be smaller than the thickness of the oxygen-absorbing layer, and is finer in order to increase the oxidation rate and not damage other layers (no penetration). Is desirable. Usually, the maximum particle size is 200μm or less, more preferably 100μm
Selected from: The amount of the deoxidizing composition in the C layer is preferably from 10 to 60 wt%, more preferably from 30 to 55 wt%. The oxygen scavenging layer may be continuously made porous by stretching. As the oxygen-absorbing composition to be added to the oxygen-absorbing layer, a solid oxygen-absorbing composition or an oxygen-absorbing composition in which a liquid oxygen-absorbing composition is supported on a suitable granular substance can be used.
Further, an inorganic filler that is hardly soluble (including insoluble) in water may be added to the deoxygenation layer as a porosification aid.

The concealing layer (layer B) is a layer made of a thermoplastic resin containing a poorly water-soluble inorganic filler, and is located between the deoxidizing layer (layer C) and the heat sealing layer (layer A). And a layer for hiding the deoxygenation layer from the outside. The filler used in the concealing layer (B layer) is not particularly limited as long as it is an inorganic filler that is hardly soluble (including insoluble) in water. Examples of such a filler include silica, alumina, diatomaceous earth, titania, barium sulfate, and the like. Titania is most preferably used in terms of concealment. Further, when the concealing layer is made to be stretched and porous, hardness, handling, and ground silica are preferable in terms of price.
It is preferable to use α-alumina, and it is most preferable to use them together with titania. Further, since the concealing layer is provided between the heat seal layer and the deoxidizing layer, it is preferable that the particle size of the filler is as small as possible so as not to penetrate the heat seal layer.

As the material constituting the nonporous buffer layer (D layer), the same resin as the resin used for the matrix component of the deoxidized layer or a resin compatible with the resin is used. Homopolymers and copolymers of olefins such as ethylene, propylene, 1-butene, 4-methyl-1-pentene, ethylene-vinyl acetate copolymer, polybutadiene, polyisoprene, styrene-butadiene copolymer and hydrogen thereof Additives and various silicone resins are exemplified. Further, these modified products, grafts, and mixtures may be used.

The rubber-based polymer to be added to the layer D is not particularly limited as long as it can improve the adhesiveness to the layer E by being added. Specifically, tensile strength of 40 MPa or less, elongation at break of 600% or more,
A resin having a JISA hardness of 90 or less. Examples of such a rubber-based polymer include styrene-butadiene rubber or a hydrogenated product thereof, acrylonitrile-butadiene rubber,
Butyl rubber, chloroprene rubber, butadiene rubber, isoprene rubber, fluoro rubber, silicone rubber, urethane rubber, acrylic rubber, ethylene-α olefin copolymer,
Ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-butene-α-olefin copolymer, ethylene-propylene-diene copolymer, styrene-isoprene-styrene copolymer, styrene-butadiene-styrene copolymer Styrene-ethylene-butylene-styrene copolymer, or a mixture thereof. In particular, when an ethylene-propylene copolymer or an ethylene-1-butene copolymer is added, the adhesive strength is improved. The added amount of the rubber-based polymer is preferably 10 to 90% by weight of the D layer, more preferably 30 to 70% by weight. If the thickness of the D layer is too small, the effect of improving the adhesiveness cannot be obtained, and if it is too large, the total thickness of the film is undesirably large. The preferred thickness is 5 to 50 μm, more preferably 10 to 30 μm.

The resin used for the deoxidizing layer and the concealing layer is not particularly limited as long as it can easily mix and disperse a deoxidizing composition such as iron powder or a poorly water-soluble inorganic filler. Rather, it should be selected in consideration of the good compatibility with the heat seal layer and the buffer layer, the operating temperature range of the deoxidized multilayer film and sheet, and the like. According to the example. Layer A, B
The resin used for the layer, the C layer, and the D layer is preferably the same type of resin, and may be different as long as the adjacent layers have compatibility.

The barrier layer (E layer) is made of a gas barrier material and has a function of preventing oxygen from entering from outside the container. Materials constituting the barrier layer (E layer) include polyesters such as polyethylene terephthalate, polyamides such as nylon 6, nylon MXD6, chlorine-containing resins such as polyvinyl chloride and polyvinylidene chloride, and ethylene-vinyl alcohol copolymer. And low-oxygen-permeability resins such as aluminum and other metal foils or metal-deposited resins; and inorganic-oxide-deposited resins such as silicon oxide.

The material constituting each layer can maintain the deoxidizing rate of the oxygen-absorbing film and sheet and the prevention of the dissolution of the oxygen-absorbing composition. In addition, various substances can be added. Examples of the additive include pigments and dyes for coloring or hiding, stabilizing components for preventing oxidation and decomposition, antistatic components, moisture absorbing components, deodorizing components, plasticizing components, flame retarding components, and the like. Is mentioned. Similarly, a layer such as a printing layer, an easy-opening layer, and an easy-peeling layer can be added as long as the performance as a deoxidizing film or sheet is not adversely affected.

In the lamination of each layer constituting the present invention,
Known lamination methods such as ordinary coextrusion, extrusion coating, and extrusion lamination can be used. The continuous porous resin layer refers to a resin layer having a large number of voids and having continuous voids so that the voids communicate with each other to penetrate the resin layer. Although various methods can be adopted as the method, stretching the resin layer containing the deoxidizing composition and the resin layer containing the poorly water-soluble inorganic filler is also suitable from the viewpoint of productivity.

In the stretching, any of uniaxial stretching, biaxial simultaneous stretching, and biaxial sequential stretching may be used, as is generally known. Further, the deoxidizing layer or the concealing layer filled with the poorly water-soluble inorganic filler or only the both may be stretched, and the respective layers may be laminated later by adhesion or fusion, vapor deposition, etc. Alternatively, in the case of a resinous barrier layer, the film may be stretched after laminating from the heat seal layer to the barrier layer. The stretching ratio is preferably 2 to 20 times.

When a low oxygen permeability barrier layer is added later, the same layer is bonded or fused by a usual method such as heat lamination, dry lamination, extrusion coating, etc. to form a final multilayer structure. Can be.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The deoxidizing film and sheet of the present invention are used as a deoxidizing packaging material having a gas barrier property on one side and an oxygen absorbing property on the other side. It is used in various forms for some or all of bags and packaging containers. For example, it can be used for a top seal film of a packaging container or a packaging bag. The content can be not only solid but also liquid or a mixture of solid and liquid.

[0020]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Example 1 An oxygen-absorbing composition obtained by spraying an aqueous solution containing 2 parts by weight of calcium chloride to 100 parts by weight of iron powder having a maximum particle size of about 50 μm, drying by heating and coating, and polypropylene (Nippon Polychem Co., Ltd.) ) FW3E, melt flow rate 7.0g / 1
0 min), kneaded with a 30 mm diameter twin screw extruder, extruded from a strand die, cooled, and cut with a pelletizer to obtain pellets of a deoxidizing resin composition. The composition of the oxygen-absorbing resin composition is 50% by weight of the oxygen-absorbing composition and 50% by weight of polypropylene.

Titania as a poorly water-soluble inorganic filler,
And polypropylene (FW3E, manufactured by Nippon Polychem Co., Ltd.)
After melt blending the melt flow rate (7.0g / 10min),
The mixture was kneaded with a 30 mm diameter twin-screw extruder, extruded from a strand die, cooled, and then cut with a pelletizer to obtain pellets of a white resin composition. The composition of the white resin composition is 10% by weight of titania and 90% by weight of polypropylene.

As a heat seal layer, polypropylene (FW3E manufactured by Nippon Polychem Co., Ltd., melt flow rate 7.0 g)
/ 10min) and ethylene-hydrogenated butadiene rubber (JSR
A 1: 1 mixture in a weight ratio of 1320P (manufactured by Nippon Polychem Co., Ltd., FW3E manufactured by Nippon Polychem Co., Ltd., melt flow rate). 7.0g / 10min) and ethylene-propylene copolymer (P0 manufactured by Mitsui Chemicals, Inc.)
680) was laminated by co-extrusion to obtain a laminate consisting of four layers. The thickness of each layer of the laminate was 50 μm for the heat seal layer / 50 μm for the concealment layer / 100 μm for the deoxygenation layer / 50 μm for the buffer layer. Next, an aluminum foil was used as a barrier layer on the buffer layer with a urethane-based adhesive (A-515 manufactured by Takeda Pharmaceutical Co., Ltd., the curing agent was A-50, the mixing ratio was
10: 1) to obtain a deoxidized multilayer film.

Cut out the deoxidized multilayer film to a width of 15 mm,
Separation between buffer layer and barrier layer, Autograph
Using a Shimadzu AG-5000B) T-peel test,
The laminate strength was measured. Laminate strength is 1.62 kgf
/ 15mm.

Example 2 In place of polypropylene, linear low-density polyethylene (SP2040 manufactured by Mitsui Chemicals, Inc., melt flow rate 4.0 g)
/ 10 min) was used to prepare a deoxidizing resin composition pellet in the same manner as in Example 1, and silica (average particle size: 5 μm) was used as a poorly water-soluble inorganic filler, and linear low density was used as a thermoplastic resin. Polyethylene (SP204 manufactured by Mitsui Chemicals, Inc.)
0, melt flow rate 4.0g / 10min)
A white resin composition pellet was obtained in the same manner as in Example 1.
The white resin composition is silica 50 wt%, polypropylene 50 w
t%.

The same linear low-density polyethylene as that of the oxygen-removing layer was used as the heat-sealing layer, and a weight ratio of ethylene-1-butene copolymer (EBM2041P manufactured by JSR Corporation) was 1:
The white resin composition is used as a concealing layer, the deoxidizing resin composition is used as a deoxidizing layer, and a linear low-density polyethylene having the same structure as the heat sealing layer is used as a buffer layer (Mitsui Chemicals, Inc. ) SP2040) and ethylene-1
A total of four layers of a 1: 1 mixture by weight of a butene copolymer (2041P, manufactured by JSR Corporation) were laminated by co-extrusion to obtain a laminate composed of four layers, and then stretched four times in the uniaxial direction. The thickness of each layer of the laminate was 20 μm for the heat seal layer / 40 μm for the concealment layer / 50 μm for the oxygen scavenging layer / 10 μm for the buffer layer. Further, an aluminum foil is used as a barrier layer on the buffer layer with a urethane-based adhesive (AD-585, Toyo Morton, CAT-
10, and a mixing ratio of 10: 1) to obtain a deoxygenated multilayer film.

Cut out the deoxidized multilayer film to a width of 15 mm,
Separation between buffer layer and barrier layer, Autograph
Using a Shimadzu AG-5000B) T-peel test,
The laminate strength was measured. Laminate strength 1.46 kgf
/ 15mm.

Example 3 The composition of the buffer layer was as follows: 50% by weight of linear low-density polyethylene, ethylene-propylene copolymer (P06 manufactured by Mitsui Chemicals, Inc.).
80) A deoxidized multilayer film was obtained in the same manner as in Example 2 except that the content was changed to 50% by weight. When the laminate strength of the obtained deoxidized multilayer film was measured, it was 1.11 kgf / 15 mm.

Comparative Example 1 The composition of the buffer layer was changed to 100 w
The same procedure as in Example 1 was performed, except that t% was used. When the lamination strength of the obtained deoxidized multilayer film was measured,
It was 80 kgf / 15 mm.

Comparative Example 2 The composition of the buffer layer was changed to linear polyethylene containing no additives.
The procedure was the same as in Example 2 except that 100 wt% was used. When the laminate strength of the obtained deoxygenated multilayer film was measured, it was 0.68 kgf / 15 mm.

[0031]

As described above, the oxygen-absorbing film or sheet is generally composed of a gas barrier film having one side having oxygen absorbing ability and the other side having low oxygen permeability. Therefore, lamination of the deoxidizing film and the barrier film is indispensable, and the performance of the film largely depends on the laminating strength. The present invention relates to improving the lamination strength of a deoxidized multilayer film and a barrier film, and has an effect of greatly improving the performance of a deoxidized film.

According to the present invention, there is provided a single-sided absorption-type oxygen-absorbing multilayer body having a high bonding strength between layers because the bonding strength between the oxygen-absorbing layer and the barrier layer is improved and a high adhesive strength is obtained. Therefore, it is not necessary to increase the thickness of the smoothing resin layer or the buffer layer or the thickness of the entire multilayer body. In particular, in the case of a film or sheet having a porous oxygen absorbing layer, the effect of improving the bonding strength between the oxygen absorbing layer and the barrier layer is remarkable.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Noriyuki Kimura 6-1-1 Shinjuku, Katsushika-ku, Tokyo Mitsubishi Gas Chemical Co., Ltd. Tokyo Research Laboratory F-term (reference) 3E067 AA11 AB01 AB81 BA24A BB14A BB15A BB16A BB18A BB22A BB25A BB26A CA04 CA24 EE25 EE32 EE33 EE34 EE35 GB13 4F100 AA00E AA00H AA06H AA21H AB02H AB10 AB33 AK01A AK01B AK01C AK01E AK07 AK51G AK64 AK64C AK73 AN00C AN00H AR00D BA04 BA05 BA07 BA10B BA10D CA09A CA13E CA23C CB00 DC11A DC11E DE01E DE01H DJ06A DJ06E EJ37 GB23 GB66 JB16A JB16B JB16C JB16E JD02D JD03B JD14 JK01 JK11C JL00 JL12B JN02E

Claims (6)

[Claims] An oxygen-absorbing layer (C layer) made of a thermoplastic resin mixed with an oxygen-absorbing composition, and a heat-sealing layer (A) made of an oxygen-permeable thermoplastic resin on one side of the C layer. Layer), and on the other side of the C layer, a buffer layer (D layer) made of a nonporous thermoplastic resin to which a rubber-based polymer is added.
And a barrier layer (E layer) composed of a gas barrier material and a single-sided absorption deoxidized multilayer body. 2. A deoxygenation layer (C layer) and a heat seal layer (A)
The multilayer body according to claim 1, wherein a concealing layer (layer B) made of a thermoplastic resin mixed with a poorly water-soluble inorganic filler is disposed between the layers. 3. The rubber-based polymer added to the buffer layer (D layer) is an ethylene-propylene copolymer or ethylene-1
The multilayer body according to claim 1, which is a -butene copolymer. 4. The multilayer body according to claim 1, wherein the oxygen scavenging layer (C layer) comprises a continuous porous resin composition. 5. The multilayer body according to claim 2, wherein the concealing layer (B layer) comprises a continuous porous resin composition. 6. The deoxidizing layer (C layer) or the hiding layer (B layer)
5. A continuous porous resin layer stretched 2 to 20 times.
Or the multilayer body of 5.