JP7331338B2 - Oxygen-absorbing laminate and packaging material and packaging bag using the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a laminate that exhibits excellent oxygen gas absorption when irradiated with ultraviolet rays, and a packaging material and a packaging bag produced using the laminate.

When filling a packaging bag with contents, it is important to prevent quality deterioration and mold growth due to oxidation of the contents. etc. may occur, and it is required to exhibit oxygen absorption performance from the same day after filling the contents.

In order to prevent quality deterioration due to mold growth and oxidation of the contents inside the packaging bag, it is effective to reduce the oxygen gas concentration in the air inside the packaging bag. To prevent the infiltration of oxygen gas from the outside, purge the inside of the packaging bag with nitrogen gas, etc., and leave various oxygen absorbers in the packaging bag together with the contents. method has been adopted.

However, even if a packaging bag having a high oxygen barrier property is used, it is difficult to obtain a continuous oxygen concentration reduction effect, and there is a risk that the oxygen scavenger will be misused as the content, which is not a satisfactory situation.

Furthermore, Patent Documents 1 and 2 propose adhesives for packaging materials having oxygen absorption performance, but when the adhesives are used in laminates, oxygen absorption occurs immediately after production Therefore, there is a problem that the oxygen absorption performance deteriorates before the content is filled into the packaging bag using the laminate.

In addition, Patent Document 3 proposes a resin having high oxygen absorbability by incorporating a transition metal or a radical scavenger into a diene resin. It is used differently from packaging materials.

Patent document 4 also proposes an adhesive using a diene resin, but the adhesive does not have oxygen absorption performance, and the interlayer adhesion is also problematic.

JP 2017-105910 A Japanese Patent No. 5671816 Japanese Patent Application Laid-Open No. 2006-335809 Japanese Patent No. 5097373

The present invention has been intensively studied in view of the above, and a laminate that exhibits excellent lamination strength and excellent oxygen gas absorption that is exhibited immediately after being filled with contents by being irradiated with ultraviolet rays, and An object of the present invention is to obtain a packaging bag that can prevent contents from being deteriorated by oxygen gas by using a packaging material comprising the laminate.

The present invention has found that when the sealant layer contains more than 50 ppm of antioxidant, the expression of oxygen absorption performance is delayed, and the packaging laminate of the present invention has at least: A packaging laminate having a specific substrate layer, an oxygen-absorbing adhesive layer, and a sealant layer.

The present invention is characterized by the following points.
1. A laminate for packaging, comprising at least a substrate layer, an oxygen-absorbing adhesive layer, and a sealant layer,
The base material layer and the sealant layer are respectively laminated on the outermost surface of the laminate,
The oxygen-absorbing adhesive layer is a layer formed from an oxygen-absorbing adhesive made of a resin composition containing at least an adhesive, an oxygen-absorbing resin, and an oxidation-promoting catalyst,
The oxygen-absorbing resin comprises a hydroxyl-terminated conjugated diene-based resin,
The oxidation-promoting catalyst consists of a transition metal carboxylate,
The content of the antioxidant in the sealant layer is 50 ppm or less,
A layered product for packaging, wherein the layered product exhibits oxygen absorption performance when irradiated with ultraviolet rays.
2. 2. The laminate according to 1 above, wherein the adhesive is a polyol-based adhesive.
3. The hydroxyl-terminated conjugated diene-based resin is a (co)polymer or a mixture containing a structure derived from a 1,4-adduct of 1,3-butadiene and/or a structure derived from a 1,4-adduct of isoprene. 3. The laminate according to 1 or 2 above, characterized in that
4. 4. The laminate as described in any one of 1 to 3 above, wherein the hydroxyl-terminated conjugated diene-based resin is modified with polyester.
5. 5. The laminate according to any one of 1 to 4 above, wherein the hydroxyl-terminated conjugated diene resin is modified with an isocyanate compound.
6. 6. The laminate as described in any one of 1 to 5 above, wherein the resin composition further contains a curing agent.
7. 7. The laminate as described in 6 above, wherein the curing agent is a polyisocyanate-based curing agent.
8. The content of the carboxylate transition metal salt is characterized in that the mass of the transition metal constituting the carboxylate transition metal salt is 20 to 2000 ppm in the solid content of the oxygen-absorbing adhesive. 8. The laminate according to any one of 1 to 7.
9. 9. The laminate according to any one of 1 to 8 above, further comprising a reinforcing layer between the base material layer and the sealant layer.
10. Furthermore, a laminate including a metal element-containing barrier layer,
10. The laminate as described in any one of 1 to 9 above, wherein the oxygen-absorbing adhesive layer is laminated between the metal element-containing barrier layer and the sealant layer.
11. 11. The laminate as described in any one of 1 to 10 above, wherein the base material layer or the reinforcing layer includes the metal element-containing barrier layer.
12. 12. The laminate as described in 10 or 11 above, wherein the metal element-containing barrier layer is one or more selected from the group consisting of a metal foil, a metal vapor deposition film, and a metal oxide vapor deposition film.
13. 13. A packaging material produced from the laminate according to any one of 1 to 12 above.
14. 14. A packaging bag made from the packaging material described in 13 above.

The laminate for packaging of the present invention exhibits excellent lamination strength, the ability to absorb oxygen gas on the same day when the content is filled with ultraviolet irradiation as a trigger, and the oxygen gas barrier property, and is composed of the laminate. A packaging bag produced using a packaging material is excellent in reducing the oxygen concentration in the packaging bag, and thus can prevent quality deterioration due to mold generation and oxidation of the contents in the packaging bag.

Furthermore, since there is no need to store various oxygen absorbers in the packaging bag together with the contents, the packaging process can be simplified, the cost and weight of the packaging bag filling can be reduced, and misuse of oxygen absorbers can be prevented. , it is possible to reduce the amount of dust composed of the oxygen scavenger.

It is a schematic sectional drawing which shows the example about the layer structure of the laminated body of this invention. FIG. 4 is a schematic cross-sectional view showing another example of the layer structure of the laminate of the present invention. FIG. 4 is a schematic cross-sectional view showing another example of the layer structure of the laminate of the present invention. FIG. 4 is a schematic cross-sectional view showing another example of the layer structure of the laminate of the present invention.

The laminate for packaging, the packaging material, and the packaging bag of the present invention will be described in detail below. The present invention will be described by showing a specific example, but the present invention is not limited to this.

<Laminate>
The laminate for packaging of the present invention has a layer structure in which at least a substrate layer, an oxygen-absorbing adhesive layer, and a sealant layer are laminated in this order, and the substrate layer and the sealant layer are each , is laminated on the outermost surface of the laminate.

Between each layer, if necessary, a reinforcing layer for reinforcing various characteristics of the laminate, a metal element-containing barrier layer for improving gas barrier properties, and a general-purpose adhesive layer may be included. can.

However, when the metal element-containing barrier layer is included, at least an oxygen-absorbing adhesive layer must be laminated between the metal element-containing barrier layer and the sealant layer.

When a packaging bag is produced using the laminate for packaging of the present invention, the sealant layer is the layer in the packaging bag that is in contact with the content storage space. In this situation, in order for the oxygen-absorbing adhesive layer to efficiently absorb the oxygen gas in the contents-housing space, the oxygen-absorbing adhesive layer should be positioned closer to the contents-housing space than the metal-element-containing barrier layer. must be stacked. The oxygen-absorbing adhesive layer need not be adjacent to the metallic element-containing barrier layer.

As long as there is at least one oxygen-absorbing adhesive layer at the close position, another oxygen-absorbing adhesive layer is laminated at a position farther from the content storage space than the other metal element-containing barrier layers. may

Furthermore, in the laminate for packaging of the present invention, the content of the antioxidant in the sealant layer must be 50 ppm or less.

If the content of the antioxidant in the sealant layer is more than 50 ppm, the development of the oxygen absorption performance of the oxygen-absorbing adhesive layer is hindered and delayed, and it may become difficult to develop the performance on the same day even when irradiated with ultraviolet rays. be.

The lower limit of the content is ideally zero ppm, but considering practical management, a sufficient effect can be exhibited at about 1 ppm.

Specific examples of antioxidants include phenols, lactones, thioethers, gallic acid compounds, ascorbic acid, erythorbic acid, catechin, dibutylhydroxytoluene, tocopherol, citric acid, butylhydroxyanisole, and phosphite compounds. , hindered amines, and aromatic amines.

When the laminate for packaging of the present invention is irradiated with ultraviolet rays, the oxygen-absorbing adhesive layer in the laminate exhibits oxygen absorption performance on the same day, and the laminate exhibits oxygen absorption performance. By this trigger function, it is possible to prevent the oxygen absorption performance from being consumed and deteriorated during the period from the laminate to the packaging bag filling, and to develop the oxygen absorption performance on the same day.

Ultraviolet irradiation of preferably 200 to 1000 mJ/cm ² , more preferably 300 to 700 mJ /cm ² from a general sterilizing ultraviolet lamp is sufficient.

However, since the oxygen absorption performance may be expressed to some extent by the heat of the normal indoor atmosphere, sunlight, indoor lamp light, etc., when laminating the laminate or performing aging treatment, etc., It is preferable to carry out the reaction under a low temperature, under an ultraviolet-cut fluorescent lamp, under an inert gas atmosphere, or the like.

[Base material layer]
In the present invention, the base material layer can function as a support layer for the laminate, or can impart external environment resistance such as stain resistance and cut resistance as the outermost surface layer of the packaging bag.

A resin film or sheet generally used as a base layer can be used for the base layer.

Specific resins include polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate; polyamide resins such as nylon 6, nylon 66, and MXD6 (polymetaxylylene adipamide); cellophane; polyolefin resins such as polyethylene resins, polypropylene resins and acid-modified polyolefin resins; polystyrene resins; polyurethane resins; acetal resins;

Moreover, it is preferably a uniaxially or biaxially stretched resin film or resin sheet.

The substrate layer may be composed of one layer or two or more layers. In the case of two or more layers, the layers may have the same composition or may have different compositions.

Depending on the type of contents when the package is produced and the use conditions such as the presence or absence of heat treatment after filling the contents, a suitable one can be freely selected and used. Resins and polyamide resins are preferred.

In particular, uniaxially or biaxially oriented polyethylene terephthalate film or sheet, biaxially oriented polypropylene film or sheet, and the like are suitable.

The resin film or resin sheet used for the base material layer has workability, heat resistance, weather resistance, mechanical properties, dimensional stability, oxidation resistance, slipperiness, releasability, flame retardancy, and resistance to heat. Addition of lubricants, cross-linking agents, antioxidants, UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, etc. to plastics for the purpose of improving mold resistance, electrical properties, strength, etc. Agents, additives, and the like can be added, and the amount added can be arbitrarily added according to the purpose within a range that does not adversely affect other performances.

In addition, in order to improve the adhesiveness, the surface of the substrate layer or the film or sheet constituting the substrate layer is subjected to corona discharge treatment, ozone treatment, oxygen gas, nitrogen gas, or the like in advance before lamination. Physical treatment such as low-temperature plasma treatment and glow discharge treatment, or chemical treatment such as oxidation treatment using chemicals may be performed.

[Oxygen-absorbing adhesive layer]
In the laminate of the present invention, the oxygen-absorbing adhesive layer is a layer formed from an oxygen-absorbing adhesive, and has a function as an adhesive and a function of absorbing oxygen gas.

The thickness of the oxygen-absorbing adhesive layer is preferably 1 g/m ² or more and 6 g/m ² or less, or 1 μm or more and 6 μm or less, in the case of dry lamination adhesive, and is preferably 3 g/m 2 or more and 6 g/m 2 or less. It is more preferably m ² or more and 5 g/m ² or less, or 3 μm or more and 5 μm or less.

If the oxygen-absorbing adhesive layer is thinner than the above range, sufficient oxygen absorption performance may not be obtained.

When an oxygen-absorbing adhesive for dry lamination is used, the oxygen-absorbing adhesive layer is formed by applying and drying the oxygen-absorbing adhesive and laminating.

[Oxygen-absorbing adhesive]
The oxygen-absorbing adhesive consists of a resin composition containing at least an adhesive, an oxygen-absorbing resin, and an oxidation-promoting catalyst, and may optionally contain a curing agent and polyester. . Various types of oxygen-absorbing adhesives can be used, and dry lamination adhesives and non-solvent adhesives may be used.

Furthermore, the oxygen-absorbing adhesive can contain tackifiers, tackifiers, leveling agents, ultraviolet absorbers, antifoaming agents, pigments, and the like within limits that do not impair the required performance.
(glue)
As the adhesive contained in the oxygen-absorbing adhesive, various adhesives can be used, and for example, polyol-based, polyester-based, epoxy-based, acrylic-based, and the like can be used. Among these, polyols are preferred.

(oxygen-absorbing resin)
The oxygen-absorbing resin in the present invention is a resin composed of a hydroxyl-terminated conjugated diene-based resin.

A hydroxyl group-terminated conjugated diene resin is a hydroxyl group-terminated conjugated diene resin and/or a modified resin of a hydroxyl group-terminated conjugated diene resin, and may be a single resin or a mixture of two or more resins. .

Various compounds can be used as the modifier for modifying the hydroxyl-terminated conjugated diene resin, but among them, it is preferable to use a polyester or an isocyanate-based compound.

The above modification is preferably obtained by chemical reaction through urethanization, esterification, amidation, allophanatization, etc. using various chain extenders under an inert gas atmosphere. It is more preferable to obtain by a method through

As for the modified ratio of the hydroxyl group-terminated conjugated diene resin and the polyester, the mass ratio of the hydroxyl group-terminated conjugated diene resin/polyester is preferably 20 to 80/100.

If the mass ratio is smaller than the above range, it is likely to be difficult to exhibit sufficient oxygen absorption performance, and if it is larger than the above range, adhesion tends to be insufficient.

(hydroxyl-terminated conjugated diene resin)
The hydroxyl-terminated conjugated diene resin in the present invention is a polymer obtained by addition (co)polymerization reaction of monomers having conjugated carbon-carbon double bonds.

Specific examples of monomers having a conjugated carbon-carbon double bond include isoprene and 1,3-butadiene.

These monomers adopt various addition (co)polymerization forms, for example, 1,3-butadiene can adopt 1,2 addition or 1,4 addition, and The structure and the position of the carbon-carbon double bond are different.

The resulting hydroxyl group-terminated conjugated diene resin may have various addition (co)polymerization forms in the molecule, or may be a mixture of molecules with different addition (co)polymerization forms.

From the viewpoint of the reaction rate with oxygen molecules, both the cis-position and the trans-position are sufficient as the stereoisomer, but it is preferable that there are many cis-positions. Moreover, it is preferable that many carbon-carbon double bonds are present on the main chain.

In the present invention, in particular, the hydroxyl-terminated conjugated diene resin includes a structure derived from a 1,4-adduct of 1,3-butadiene and/or a structure derived from a 1,4-adduct of isoprene, (co) Polymers or mixtures are preferred.

(polyester)
As the polyester resin used in the present invention, regardless of the presence or absence of carbon-carbon double bonds, general polyesters used in ordinary laminate adhesive resin compositions can be used.

For polyester, considering the glass transition temperature, flexibility, adhesiveness, etc. required as an adhesive, compatibility with hydroxyl-terminated conjugated diene resins, and the optimum polyester according to the intended use conditions and physical properties can be selected.

(chain extender)
When obtaining an oxygen-absorbing resin by chemically bonding a hydroxyl-terminated conjugated diene-based resin and a polyester, it is preferable to use various chain extenders.

When urethane-forming a hydroxyl group-terminated conjugated diene resin and a polyester, various known isocyanate compounds can be used as a chain extender.

Specifically, for example, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, norbornene diisocyanate, tolylene diisocyanate, hydrogenated tolylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, and buret forms thereof , trimethylolpropane adduct, nurate and the like can be used.

Among these, chain extension with diisocyanate, which is bifunctional, is preferable from the viewpoint of coatability and adhesive strength.

When the hydroxyl-terminated conjugated diene resin and the polyester are allophanatized, allophanate forms of the various known isocyanate compounds described above can be used as the chain extender.

When esterifying a hydroxyl-terminated conjugated diene resin and a polyester, a carboxylic acid such as maleic acid or fumaric acid can be used as a chain extender.

When a hydroxyl-terminated conjugated diene resin and polyester are amidated, an amine component can be added together with a carboxylic acid such as maleic acid or fumaric acid as a chain extender.

(oxidation promotion catalyst)
In the present invention, the oxidation-promoting catalyst is a component that promotes the oxygen-absorbing action of the oxygen-absorbing resin, and is composed of a transition metal carboxylate.

Specific examples of transition metals include cobalt, manganese, iron, nickel and copper, and specific examples of carboxylic acids include stearic acid, naphthenic acid and octylic acid.

Examples of transition metal carboxylates include salts of combinations of these transition metals and carboxylic acids, and one of them may be used alone, or two or more of them may be used in combination. Among them, cobalt octylate is preferred because it has a large oxygen absorption promoting effect.

The content of the transition metal carboxylate in the oxygen-absorbing adhesive is preferably 10 ppm or more and 6000 ppm or less, preferably 100 ppm, based on the solid content of the oxygen-absorbing adhesive, in terms of the mass of the transition metal component constituting the salt. 1000 ppm or less is more preferable. If it is less than the above range, the oxygen absorption performance may become insufficient, and if it is more than the above range, a large amount of oxygen absorption performance may be consumed before the contents are filled into the packaging bag.

(curing agent)
The curing agent is not particularly limited as long as it functions as a curing agent for oxygen-absorbing resins and adhesives, and various known compounds can be used.

For example, when the oxygen-absorbing resin or adhesive has a hydroxyl group, it is preferable to use a polyisocyanate-based curing agent as the curing agent.

The polyisocyanate-based curing agent in the present invention may have two or more isocyanate groups in one molecule, and either aromatic polyisocyanate or aliphatic polyisocyanate-based curing agent can be used.

Specifically, hexamethylene diisocyanate, isophorone diisocyanate, xylene diisocyanate, norbornene diisocyanate, hydrogenated diphenylmethane diisocyanate, and trimethylolpropane adducts, buret bodies, allophanate bodies, and isocyanurate bodies (trimers) of these mentioned.

As the polyisocyanate-based curing agent, one of these may be used alone, or two or more thereof may be mixed and used. Among these, the biuret form of hexamethylene diisocyanate is preferred.

The content of the curing agent in the oxygen-absorbing adhesive is the functional group of the curing agent/the functional group of (oxygen-absorbing resin + adhesive) for the functional groups involved in curing in the total oxygen-absorbing adhesive. It is preferably contained so that the molar ratio is 0.8 or more and 3.0 or less.

For example, when the oxygen-absorbing resin or adhesive has hydroxyl groups and the curing agent is a polyisocyanate-based curing agent, the content of the polyisocyanate-based curing agent in the oxygen-absorbing adhesive is It is preferable that the molar ratio of NCO group/OH group in the adhesive is 1.0 or more and 3.0 or less.

If the molar ratio is smaller than the above range, sufficient adhesiveness may not be obtained.

(diluent)
The diluent added when the oxygen-absorbing adhesive is used as an adhesive for dry lamination is preferably a solvent that does not react with the components constituting the oxygen-absorbing adhesive. Typically, ethyl acetate is preferred. For example, when a polyisocyanate-based curing agent is contained, water and alcohol cannot be used because they react with isocyanate groups.

[Sealant layer]
In the laminate of the present invention, the sealant layer is the outermost layer having heat-sealability by containing a heat-sealable resin, and when a packaging bag is produced using a packaging material comprising the laminate, the contents It becomes the layer in contact with the storage space.

The present invention has found that when the sealant layer contains more than 50 ppm of antioxidant, the development of oxygen absorption performance is delayed.

The sealant layer may be composed of one layer or two or more layers. In the case of two or more layers, the layers may have the same composition or may have different compositions.

However, it is preferable that the layer forming the outermost surface of the content-resistant agingless laminate contains a resin having excellent heat-sealing properties.

Whether the sealant layer is a layer laminated by (co)extrusion lamination or a layer laminated by film lamination, the film is laminated via a (co)extrusion lamination layer by sand lamination. It may be a laminated layer.

As specific heat-sealing resins, thermoplastic resins can be used, for example, polyethylene (PE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear (linear) low density polyethylene (LLDPE), metallocene polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-ethyl (meth)acrylate copolymer, ethylene-(meth)acrylic acid copolymer, Polyolefin resins such as ethylene-propylene copolymer, methylpentene polymer, polyethylene or polypropylene modified with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, ethylene-(meth) ) acrylic acid ester-unsaturated carboxylic acid terpolymer resin, cyclic polyolefin resin, cyclic olefin copolymer, polyethylene terephthalate (PET), polyacrylonitrile (PAN) and the like.

among these. The sealant layer preferably contains a polyethylene-based resin, more preferably linear low-density polyethylene (LLDPE) or low-density polyethylene (LDPE), as a heat-sealable resin.

The sealant layer has, as required, workability, heat resistance, weather resistance, mechanical properties, dimensional stability, antioxidant properties, slip properties, release properties, flame retardancy, anti-mold properties, electrical properties, For the purpose of improving and modifying the strength, etc., plastic compounding agents and additives such as lubricants, cross-linking agents, antioxidants, ultraviolet absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, and pigments are added. The addition amount can be arbitrarily added according to the purpose within a range that does not adversely affect other performances.

In order to improve adhesion, the sealant layer or the surface of the film or sheet constituting the sealant layer may be subjected to corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas, nitrogen gas, or the like in advance before lamination. Physical treatment such as treatment, glow discharge treatment, or chemical treatment such as oxidation treatment using chemicals may be performed.

[Reinforcement layer]
In the present invention, the reinforcing layer is a layer further laminated between the base material layer and the sealant layer, if necessary.

The reinforcing layer is a layer that functions as a support layer for the sealant layer, and can reinforce the tensile strength, bending strength, impact strength, puncture strength, breaking strength, toughness, rigidity, etc. of the laminate.

The reinforcing layer may be composed of one layer or two or more layers. In the case of two or more layers, the layers may have the same composition or may have different compositions.

The reinforcing layer is preferably formed from a resin film. However, whether the resin film is a resin film formed by (co)extrusion lamination or a resin film formed by lamination of films, the film is laminated via the (co)extrusion lamination layer. It may also be a resin film formed by sand lamination applied.

The resin contained in the reinforcing layer is not particularly limited as long as it can function as a support layer, and the same type of resin as that of the base layer can be used. It preferably contains a copolymer.

Reinforcing layer, if necessary, has properties such as workability, heat resistance, weather resistance, mechanical properties, dimensional stability, antioxidant properties, lubricity, release properties, flame retardancy, mold resistance, electrical properties, and strength. Add plastic compounds and additives such as lubricants, cross-linking agents, antioxidants, UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, and pigments for the purpose of improving and modifying The addition amount can be arbitrarily added according to the purpose within a range that does not adversely affect other performances.

In order to improve adhesion, the surface of the reinforcing layer or the film or sheet constituting the reinforcing layer may be subjected to corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas or nitrogen gas, etc. in advance before lamination. Physical treatment such as treatment, glow discharge treatment, or chemical treatment such as oxidation treatment using chemicals may be performed.

[Barrier layer containing metal element]
In the present invention, the metal element-containing barrier layer is a layer that is further laminated as necessary, and is a layer that functions as a gas barrier layer.

The metal element-containing barrier layer is one selected from the group consisting of a metal foil such as an aluminum foil, a metal vapor deposition film such as an aluminum vapor deposition film, and a metal oxide vapor deposition film such as an aluminum oxide vapor deposition film and a silicon oxide vapor deposition film. Alternatively, it is preferably a layer composed of two or more kinds.

The metal element-containing barrier layer may be composed of one layer or two or more layers. In the case of two or more layers, the layers may have the same composition or may have different compositions. Further, the layers may be laminated via an adhesive layer, or two or more layers may be laminated separately.

The metal-element-containing barrier layer can be included in or between layers such as the substrate layer, the laminated side surface of the substrate layer, the reinforcing layer, or the surface of the reinforcing layer, and the resin constituting the substrate layer or the reinforcing layer. An aluminum evaporated film, an aluminum oxide evaporated film, a silicon oxide evaporated film, or the like may be formed on a film or a resin sheet by vapor deposition, or a metal foil may be formed by adhering a metal foil in each layer or on the surface of each layer.

When laminating the metal element-containing barrier layer with other layers, they can be adhered with an adhesive layer. Preferably, the adhesive layer is a dry lamination adhesive layer.

<Packaging material>
The packaging material of the present invention is a packaging material produced from the laminate for packaging of the present invention, and if necessary, it is possible to have layers having various functions in addition to the laminate of the present invention. . Then, similarly to the laminate of the present invention, by being irradiated with ultraviolet rays, it is possible to express oxygen absorption performance on the same day after filling the contents.

<Packaging bag>
The packaging bag of the present invention is a packaging bag made from the packaging material of the present invention. Then, similarly to the laminate of the present invention, by being irradiated with ultraviolet rays, it is possible to express oxygen absorption performance on the same day after filling the contents.

For example, the packaging material of the present invention is folded in two, or two packaging materials are prepared, the surfaces of the sealant layers are placed on top of each other, and the peripheral edges are formed into, for example, a standing pouch type or a side seal type. , 2-side seal type, 3-side seal type, 4-side seal type, envelope seal type, palm seal type (pillow seal type), pleated seal type, flat bottom seal type, square bottom seal type, gusset type, etc. It is possible to heat-seal with the resin to produce various forms of packaging bags.

<Raw materials>
- PET film 1: Biaxially oriented PET film manufactured by Toyobo Co., Ltd. 12 μm thick.
・Transparent vapor-deposited PET film 2: IB-PET manufactured by Dai Nippon Printing Co., Ltd. Transparent alumina deposited PET film. 12 μm thick.
· LLDPE film 1: N-165 manufactured by Aicello Co., Ltd. Unstretched LLDPE film. 40 μm thick. Antioxidant content of 50 ppm or less.
- LLDPE film 2: Unstretched LLDPE film. 40 μm thick. Antioxidant content 770ppm.
- CPP film 1: P1128 manufactured by Toyobo Co., Ltd.; Unstretched CPP film. 40 μm thick. Antioxidant content of 50 ppm or less.
- CPP film 2: unstretched CPP film. 40 μm thick. Antioxidant content 550 ppm.
- Nylon film 1: Biaxially oriented nylon film manufactured by Unitika Ltd. 15 μm thick.

- Oxygen-absorbing adhesive 1: Adjusted as follows.
• DL Adhesive 1: A two-liquid curable polyester urethane adhesive manufactured by Toyo-Morton Co., Ltd.
DL Adhesive 2: A composition obtained by removing the oxidation promoting catalyst from the oxygen-absorbing adhesive 1.
- Aluminum foil 1: 7 μm thick aluminum foil.
- Hydroxyl-terminated polyisoprene 1: Hydroxyl-terminated 1,4-addition polymer of isoprene.
- Hydroxyl-terminated polybutadiene 1: hydroxyl-terminated 1,2-addition polymer of 1,3-butadiene.

[Preparation of oxygen-absorbing adhesive 1]
The following raw materials were mixed and reacted at an internal temperature of 80 to 90° C. for 6 hours under a nitrogen atmosphere with stirring to obtain an oxygen-absorbing resin.
Polyester 1000 parts by mass Hydroxyl-terminated conjugated diene resin Hydroxy-terminated polyisoprene 1 600 parts by mass Hydroxyl-terminated polybutadiene 1 400 parts by mass As a urethane chain extender Xylene diisocyanate 80 parts by mass

Then, in a nitrogen atmosphere, the following were mixed to obtain an oxygen-absorbing adhesive 1.

Oxygen-absorbing resin obtained above 1000 parts by mass As an oxidation promoting catalyst 4% cobalt octylate ethyl acetate solution 24.2 parts by mass As a polyisocyanate curing agent Biuret form of hexamethylene diisocyanate 100 parts by mass As a diluent Ethyl acetate 1500 part by mass

[Example 1]
The vapor-deposited surface of the transparent vapor-deposited PET film 2 was coated with the oxygen-absorbing adhesive 1 in a dry coating amount of 3.0 g/m ^{2 ,} dried, and then bonded to the LLDPE film 1 by dry lamination.
And it cured at 40 degreeC for 3 days, obtained the laminated body, and implemented various evaluations.

[Example 2]
The DL adhesive 1 was applied to the vapor deposition surface of the transparent vapor deposition PET film 2 so that the dry coating amount was 3.0 g/m ² , dried, and then bonded to the nylon film 1 by dry lamination.
Next, the oxygen-absorbing adhesive 1 was applied to the surface of the nylon film 1 so that the dry coating amount was 3.0 g/m ² , dried, and then laminated with the LLDPE film 1 by dry lamination. After curing for 3 days, a laminate was obtained. Then, various evaluations were carried out in the same manner as in Example 1.

[Example 3]
A laminate was obtained in the same manner as in Example 2, except that the DL adhesive 1 was changed to the oxygen-absorbing adhesive 1, and evaluated in the same manner.

[Example 4]
A laminate was obtained in the same manner as in Example 2 except that the transparent vapor-deposited PET film 2 was changed to the PET film 1, and the nylon film 1 was changed to the aluminum foil 1, and the laminate was evaluated in the same manner.

[Example 5]
A laminate was obtained in the same manner as in Example 1 except that the LLDPE film 1 was changed to the CPP film 1 and evaluated in the same manner.

[Comparative Example 1]
A laminate was obtained in the same manner as in Example 1 except that the oxygen-absorbing adhesive 1 was changed to the DL adhesive 1, and the laminate was evaluated in the same manner.

[Comparative Example 2]
A laminate was obtained in the same manner as in Example 5 except that the oxygen-absorbing adhesive 1 was changed to the DL adhesive 1, and the laminate was evaluated in the same manner.

[Comparative Example 3]
A laminate was obtained in the same manner as in Example 1 except that the oxygen-absorbing adhesive 1 was changed to the DL adhesive 2, and the laminate was evaluated in the same manner.

[Comparative Example 4]
A laminate was obtained in the same manner as in Example 1 except that the LLDPE film 1 was changed to the LLDPE film 2, and the laminate was evaluated in the same manner.

[Comparative Example 5]
A laminate was obtained in the same manner as in Example 2 except that LLDPE film 1 was changed to LLDPE film 2, and evaluated in the same manner.

[Comparative Example 6]
A laminate was obtained in the same manner as in Example 4 except that LLDPE film 1 was changed to LLDPE film 2, and evaluated in the same manner.

[Comparative Example 7]
A laminate was obtained in the same manner as in Example 5, except that CPP film 1 was changed to CPP film 2, and evaluated in the same manner.

<Evaluation method>
[Laminate strength]
The laminate strength at the interface between the sealant layer and the adhesive layer of the resulting laminate was measured using a tensile tester.

[Measurement of oxygen absorption performance]
After irradiating the obtained laminate with ultraviolet rays of 500 mJ/cm ² from the surface of the sealant layer using a UV irradiation machine, a package was prepared by a three-way heat seal method so that the inner dimension was 135 mm × 70 mm. of air, oxygen sensor chip (non-destructive oxygen sensor chip manufactured by Precision Sensing) is enclosed, and the oxygen concentration in the packaging bag after storage for 14 days in a constant temperature bath at 25 ° C. is measured using a non-destructive oxygen concentration meter. It was measured and the oxygen absorption amount was calculated.

[Summary of evaluation results]
All examples exhibited excellent laminate strength and excellent oxygen absorption immediately upon UV irradiation.
However, Comparative Examples 1 to 3, which do not have the oxygen-absorbing adhesive layer according to the present invention, do not absorb oxygen, and Comparative Examples 4 to 7, which have a high antioxidant content in the sealant layer, can be used on the same day. It did not show oxygen absorption.

Reference Signs List 1 Laminate 2 Base material layer 3 Oxygen-absorbing adhesive layer 4 Sealant layer 5 Reinforcement layer 6 Metal element-containing barrier layer 7 General-purpose adhesive layer

Claims (12)

A laminate for packaging, comprising at least a substrate layer, an oxygen-absorbing adhesive layer, and a sealant layer in this order ,
The base material layer and the sealant layer are respectively laminated on the outermost surface of the laminate,
The oxygen-absorbing adhesive layer is a layer formed from a resin composition containing at least an adhesive, an oxygen-absorbing resin, and an oxidation-promoting catalyst,
The adhesive is a polyol-based adhesive,
The oxygen-absorbing resin is composed of a hydroxyl-terminated conjugated diene resin, and the hydroxyl-terminated conjugated diene resin is a hydroxyl-terminated conjugated diene resin and/or a modified resin of a hydroxyl-terminated conjugated diene resin, and is one type of resin. or a mixture of two or more resins,
The oxidation-promoting catalyst consists of a transition metal carboxylate,
The content of the carboxylate transition metal salt in the oxygen-absorbing adhesive layer is such that the mass of the transition metal component constituting the salt is 100 ppm or more and 1000 ppm or less relative to the solid content of the oxygen-absorbing adhesive,
The thickness of the oxygen-absorbing adhesive layer is 3 g/m ² or more and 5 g/m ² or less, or 3 μm or more and 5 μm or less,
The content of the antioxidant in the sealant layer is 1 ppm to 50 ppm,
The laminate does not exhibit oxygen absorption performance before it ^is irradiated with ultraviolet rays before being filled with contents. A laminate for packaging, characterized in that it expresses. The hydroxyl-terminated conjugated diene resin is a (co)polymer or mixture containing a structure derived from a 1,4-adduct of 1,3-butadiene and/or a structure derived from a 1,4-adduct of isoprene. The laminate according to claim 1 , characterized by: 3. The laminate according to claim 1 , wherein the hydroxyl-terminated conjugated diene resin is modified with polyester. 3. The laminate according to claim 1 , wherein the hydroxyl-terminated conjugated diene resin is modified with an isocyanate compound. The laminate according to any one of claims 1 to 4 , wherein the resin composition further contains a curing agent. 6. The laminate according to claim 5 , wherein the curing agent is a polyisocyanate curing agent. The laminate according to any one of claims 1 to 6 , further comprising a reinforcing layer between the base material layer and the sealant layer. Furthermore, a laminate including a metal element-containing barrier layer,
8. The laminate according to any one of claims 1 to 7 , wherein the oxygen-absorbing adhesive layer is laminated between the metal element-containing barrier layer and the sealant layer. 9. The laminate according to any one of claims 1 to 8 , wherein the base material layer or the reinforcing layer includes the metal element-containing barrier layer. 10. The laminate according to claim 8 , wherein the metal element-containing barrier layer is one or more selected from the group consisting of a metal foil, a metal vapor deposition film, and a metal oxide vapor deposition film. . A packaging material made from the laminate according to any one of claims 1-10 . A packaging bag made from the packaging material according to claim 11 .

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