JP7577926B2 - Odor-absorbing laminate - Google Patents

Description

The present invention relates to an odor-adsorbing laminate capable of adsorbing any of the odorous substances, aldehydes, ketones, carboxylic acids, or alcohols, and to an odor-adsorbing packaging material and odor-adsorbing packaging body made using the odor-adsorbing laminate.

Packaging materials containing odor adsorbents have been proposed. In such packaging materials, odor adsorbents such as synthetic zeolite and activated carbon are kneaded into the resin material (Patent Document 1). However, such conventional packaging materials mainly adsorb odorous substances such as aldehydes and ketones, and are not intended to adsorb carboxylic acids or alcohols. Furthermore, they adsorb not only odors but also moisture in the air, and have the problem of releasing the odors once adsorbed, so they do not achieve a sufficient odor adsorption effect.
Packaging materials containing an odor adsorbent comprising a chemical adsorbent supported on an inorganic porous body are also known (Patent Document 2), but the main objects of adsorption are only odorous components having specific functional groups, and unless a resin material is selected, the materials are not capable of adequately adsorbing odorous components of organic substances that do not have functional groups.

Patent No. 2538487 JP 2014-233408 A

The present invention aims to solve the above problems and provide a laminate with excellent seal strength, which has excellent manufacturing suitability such as film-forming ability, filling machine suitability, and a high odor adsorption effect for a long period of time for the adsorption of any of the four odorous substances, namely aldehydes, ketones, carboxylic acids, or alcohols, and a packaging material and a package using said laminate.

As a result of various investigations, the present inventors have found that a laminate having a specific odor-absorbing sealant layer can achieve the above object.
The present invention is characterized in the following points.
1. An odor-adsorbing laminate capable of adsorbing odorous substances, such as aldehydes, ketones, carboxylic acids, or alcohols, comprising:
The odor-absorbing laminate includes at least a substrate layer and an odor-absorbing sealant layer,
the odor-absorbing sealant layer is a layer formed from an odor-absorbing sealant film containing an odor adsorbent and a heat-sealable resin;
The odor adsorbent comprises a hydrophobic zeolite.
Odor-absorbing laminate.
2. The odor-adsorbing laminate according to the above item 1, wherein the odor adsorbent further comprises one or more members selected from the group consisting of a metal-supported inorganic porous material, an amino group-supported inorganic porous material, and a hydroxyl group-supported inorganic porous material.
3. The odor-adsorbing laminate according to ¹ or 2 ^above , wherein the heat-sealable resin contains one or more resins selected from the group consisting of C4-LLDPE, C6-LLDPE, and C8-LLDPE, each having a density of 0.90 g/cm3 or more and 0.94 g/cm3 or less.
4. The odor adsorbent laminate according to any one of 1 to 3 above, wherein the odor adsorbent is melt-kneaded in advance with a heat sealable resin in a mass ratio of odor adsorbent/heat sealable resin of 0.5/99.5 to 40/60.
5. The odor absorbing sealant layer comprises a heat seal layer and an odor absorbing layer;
the heat seal layer is a layer containing the heat sealable resin and not containing the odor adsorbent,
The odor adsorption layer is a layer containing the odor adsorbent.
5. An odor-adsorbing laminate according to any one of 1 to 4 above.
6. The odor-absorbing laminate is
Base layer/heat seal layer/odor adsorption layer,
Base layer/odor absorbing layer/heat seal layer,
Base layer/heat seal layer/odor adsorption layer/heat seal layer,
6. The odor-adsorbing laminate according to claim 5, wherein the odor-adsorbing laminate is laminated in any one of the following configurations:
7. The odor adsorbing laminate according to the above item 5 or 6, wherein the content of the odor adsorbent in the odor adsorbing layer is 0.3% by mass or more and 15% by mass or less.
8. An odor-adsorbing packaging material produced using the odor-adsorbing laminate according to any one of 1 to 7 above.
9. An odor-absorbing package made from the odor-absorbing packaging material described in 8 above.

According to the present invention, it is possible to provide a laminate having excellent manufacturing suitability such as film-forming ability, suitability for filling machines, and a high odor adsorption effect for a long period of time for adsorbing any of the four odorous substances, namely aldehydes, ketones, carboxylic acids or alcohols, and excellent seal strength, as well as a packaging material and a package using said laminate.
In particular, since the laminate can adsorb any of the four odorous substances inherently contained in the resin contained therein, namely aldehydes, ketones, carboxylic acids, or alcohols, the laminate can be suitably used for packaging materials for medical instruments (surgical gowns, drapes, syringes, dialyzers, culture vessels, etc.), BIBs, and animal feed.
In addition, by adsorbing the above-mentioned odorous substances, it is possible to suppress changes in the flavor of the contents, suppress discomfort to the user, and maintain the health of the user.
Furthermore, it is possible to suppress inhibition of culture function in culture vessels and the like caused by the above-mentioned odorous substances.

FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of an odor-adsorbing laminate of the present invention. FIG. 2 is a schematic cross-sectional view showing one example of another embodiment of the layer structure of the odor-adsorbing laminate of the present invention. FIG. 2 is a schematic cross-sectional view showing another example of the layer structure of the odor-adsorbing laminate of the present invention. FIG. 2 is a diagram showing the adsorption mechanism of odorous substances of a hydroxyl group-supported inorganic porous material and an amino group-supported inorganic porous material.

The odor-adsorbing laminate of the present invention and the packaging material and packaging body produced using the odor-adsorbing laminate are described in detail below. Specific examples are given, but the present invention is not limited thereto.

<<Odor-absorbing laminate>>
The odor-adsorbing laminate of the present invention is an odor-adsorbing laminate for adsorbing odorous substances such as aldehydes, ketones, carboxylic acids or alcohols.
The layer structure of the odor-adsorbing laminate of the present invention includes at least a base layer and an odor-adsorbing sealant layer, as shown in Figure 1. The odor-adsorbing sealant layer is a surface layer of the odor-adsorbing laminate, and is used so as to come into contact with the contents of the package when the package is formed.
The odor-absorbing sealant layer is a layer containing an odor-absorbing agent and a heat-sealable resin, and is preferably formed from an odor-absorbing sealant film.
Furthermore, the laminate of the present invention can have high transparency depending on the application.

Furthermore, the odor-adsorbing laminate of the present invention can further comprise intermediate layers having various properties, if necessary.
Furthermore, each layer may be laminated via an adhesive layer.

The thickness of the odor-adsorbing laminate of the present invention is preferably 40 μm or more and 200 μm or less, and more preferably 45 μm or more and 190 μm or less. If it is thinner than the above range, it is prone to tearing, and if it is thicker than the above range, it is too rigid and is likely to be less suitable for packaging applications.

[Odor adsorption]
In the present invention, odor adsorption property refers to the ability to adsorb the odorous substance to be adsorbed.
The odor substances to be adsorbed in the present invention are aldehydes, ketones, carboxylic acids, or alcohols. Conventional odor-adsorbing laminates mainly adsorb aldehydes and ketones, but the present invention also adsorbs carboxylic acids and alcohols.
The above-mentioned odorous substances are often mainly odorous organic substances contained in the laminate, such as odorous organic substances contained in the raw materials that make up the laminate, odorous organic substances generated due to the thermal history when forming the laminate, and odorous organic substances generated by the decomposition of resin in the laminate due to sterilization treatment.

Specific examples of aldehyde compounds that are odorous substances to be adsorbed include formaldehyde, acetaldehyde, 2-methylpropanal, and 3-methylbutanal.
Specific examples of ketone compounds include acetone, MEK, MIBK, and 3,3-dimethyl-2-butanone.
Specific examples of carboxylic acid compounds include acetic acid, 2-methylpropanoic acid, 2,2-dimethylpropanoic acid, and isovaleric acid (3-methylbutanoic acid).
Specific examples of alcohol compounds include 2-methyl-2-propanol, 2-methylpropanol, ethanol, and 1-propanol.

(Filling machine suitability)
Filling machine suitability refers to the suitability for production without defects such as poor heat sealing or the occurrence of pinholes in a process using a filling machine that continuously produces odor-adsorbing packages and fills them with contents.

<Odor-absorbing sealant layer>
The odor-adsorbing sealant layer is a layer that imparts heat-sealing properties and odor-adsorbing properties to the odor-adsorbing laminate of the present invention, and contains a heat-sealing resin and an odor adsorbent. It may also contain other components.
The odor-adsorbing laminate of the present invention contains an odor adsorbent in the odor-adsorbing sealant layer that comes into contact with the contents, thereby efficiently reducing the concentration of odorous components in the content storage section of the odor-adsorbing package.
The odor absorbing sealant layer contains slip agents, antiblocking agents, antioxidants,
Solvents and other additives may also be included in small amounts, if desired.

Since the odor-adsorbing sealant layer is a layer that comes into contact with the content-accommodating portion of the odor-adsorbing package and the contents, the odor adsorption properties can be adjusted by the thickness of the odor-adsorbing sealant layer.
The thickness of the odor-adsorbing sealant layer is preferably 30 μm or more and 150 μm or less in order to have a good balance between heat-sealing property and odor-adsorbing property. If the thickness is thinner than the above range, the heat-sealing property and/or odor-adsorbing property may be insufficient, and if the thickness is thicker than the above range, the stiffness of the laminate may be too high.

The odor-adsorbing sealant layer may be composed of one layer containing a heat-sealable resin and an odor-adsorbing agent, or may be composed of two or more layers having the same and/or different compositions.
When the odor-adsorbing sealant layer has a multi-layer structure, it may have, for example, a layer containing an odor adsorbent (odor-adsorbing layer) and a layer containing a heat-sealable resin but not an odor adsorbent (heat-sealing layer).Furthermore, it may have layers with different types or amounts of odor adsorbents.
For example, high interlayer bond strength and/or high heat sealability can be achieved by including the above-described heat seal layer or a layer having a low odor adsorbent content on the exterior and/or interior surfaces of the odor absorbing sealant layer.
Specific examples of the stacking order of each layer of the odor-adsorbing laminate include base layer/heat seal layer/odor adsorbing layer, base layer/odor adsorbing layer/heat seal layer, base layer/heat seal layer/odor adsorbing layer/heat seal layer, etc.

In the odor adsorption sealant layer, the content of the odor adsorbent in the layer containing the odor adsorbent is preferably 0.3% by mass or more and 15% by mass or less. If the content is less than the above range, the odor adsorption effect is difficult to achieve, and if the content is more than the above range, film formability may be deteriorated.
For example, when the odor adsorption sealant layer is composed of one layer, the content of the odor adsorbent in the odor adsorption sealant layer is preferably 0.3% by mass or more and 15% by mass or less, as described above.
Furthermore, when the odor adsorbing sealant layer is constructed of multiple layers and includes a layer containing an odor adsorbent (odor adsorbing layer), the content of the odor adsorbent in the layer containing the odor adsorbent (odor adsorbing layer) is preferably 0.3 mass % or more and 15 mass % or less, and more preferably 0.5 mass % or more and 14 mass % or less.

The odor-adsorbing sealant layer can be formed by a known method. For example, the resin constituting the odor-adsorbing sealant layer may be melted and formed on another layer by (co)extrusion, or the odor-adsorbing sealant layer and the other layer may be formed simultaneously by a co-extrusion inflation method or the like. Alternatively, the odor-adsorbing sealant layer may be formed into a film by a conventional film-forming method such as an extrusion method, a cast molding method, a T-die method, a cutting method, or an inflation method, and then laminated via an adhesive or the like to form the film.
The film may be produced by any of the methods described above, but the inflation method is preferred.

The film may be unstretched, but may also be stretched uniaxially or biaxially by, for example, a tenter system or a tubular system to improve its strength, dimensional stability, and heat resistance.
For example, a biaxially stretched film can be obtained by longitudinally stretching the film by 2 to 4 times using a roll stretching machine at 50 to 100° C., further transversely stretching the film by 3 to 5 times using a tenter stretching machine in an atmosphere of 90 to 150° C., and subsequently heat-treating the film using the same tenter in an atmosphere of 100 to 240° C. The stretched film may be simultaneously biaxially stretched or sequentially biaxially stretched.
Among the above, a non-stretched single layer film or a non-stretched multilayer film is particularly preferred.

[Odor absorbent]
In the present invention, the odor adsorbent preferably contains hydrophobic zeolite.
It is more preferable that the inorganic porous material contains one or more materials selected from the group consisting of a metal-supported inorganic porous material, an amino group-supported inorganic porous material, and a hydroxyl group-supported inorganic porous material.
In the present invention, odor adsorbents that adsorb odors by chemical reaction, such as metal-supported inorganic porous materials, amino group-supported inorganic porous materials, and hydroxyl group-supported inorganic porous materials, are collectively referred to as "chemical adsorbent-supported inorganic porous materials."

(Hydrophobic Zeolite)
In the present invention, the hydrophobic zeolite has a function of mainly physically adsorbing odorous substances.
In the present invention, the hydrophobic zeolite used as the odor adsorbent more preferably has _{a SiO2} / _Al2O3 molar ratio of 400/1 to 10,000/1. When the molar ratio is within the above range, the balance between hydrophobicity and pore size is excellent, and better odor adsorption properties can be obtained.
The hydrophobic zeolite maintains its effect of adsorbing odorous components even when the laminate of the present invention is exposed to temperatures of 230° C. or higher.
The hydrophobic zeolite may have any external shape, such as a sphere, a rod, an ellipse, or the like, and may be in any form, such as a powder, a lump, or a granule. From the viewpoints of uniform dispersibility, kneading characteristics, film-forming properties, and the like, when dispersed in a resin, the powder form is preferred.

In the present invention, the average particle size of the hydrophobic zeolite can be appropriately selected from those having any average particle size depending on the application, but those having an average particle size of 0.01 μm to 15 μm are preferred. Here, the average particle size is a value measured by a dynamic light scattering method.
If the average particle size is smaller than the above range, the hydrophobic zeolite tends to aggregate and the dispersibility tends to decrease.If the average particle size is larger than the above range, the film-forming property of the layer containing the hydrophobic zeolite tends to be poor, so it tends to be difficult to add a large amount of hydrophobic zeolite, and the surface area is also reduced, so there is a possibility that a sufficient deodorizing effect cannot be obtained.

Unlike non-hydrophobic (hydrophilic) zeolites, in which odorous substances and water vapor are adsorbed at the same adsorption sites, hydrophobic zeolites are hydrophobic and therefore have difficulty adsorbing highly polar water molecules, but conversely have a high affinity for low polarity odor molecules, hydrophobic gases, and lipophilic gases (including solvent-based gases), which are easily adsorbed. Furthermore, due to the effect of alkali metals and alkaline earth metals such as Ca, Na, and K present on the zeolite surface, the zeolite surface exhibits basicity, making it easy to adsorb acidic gases through a neutralization reaction.

(Chemical adsorbent-supported inorganic porous material)
In the present invention, the chemical adsorbent-supported inorganic porous material is an inorganic porous material which supports a chemical adsorbent or a metal compound and has the function of mainly chemically adsorbing odorous substances. Examples of such materials include amino group-supported inorganic porous materials, hydroxyl group-supported inorganic porous materials, and metal-supported inorganic porous materials.
In the present invention, the chemical adsorbent used in the chemical adsorbent-supported inorganic porous material is a compound that has a reactive functional group that chemically reacts with and bonds to odorous substances and that can be supported on the inorganic porous material.
More specifically, it is a compound having a functional group that has the reactivity to bond with aldehydes, ketones, carboxylic acids, or alcohols, and examples of such compounds include compounds containing an amino group and compounds having a hydroxyl group.

As a method for supporting the chemical adsorbent, a known or conventional supporting method can be applied. For example, the chemical adsorbent can be supported by impregnating the inorganic porous body with a solution containing the chemical adsorbent described below and drying the same.
In the present invention, by using an inorganic porous material carrying a chemical adsorbent, the adsorption capacity per unit mass of the odor adsorbent can be significantly increased, and the content of the odor adsorbent in the laminate can be reduced. In addition, physical adsorption properties can be expected for the pores of the inorganic porous material or zeolite.
As a result, high adhesive strength and sealing strength can be obtained, and the excellent adhesive properties, coatability, and film-forming properties required for an adhesive layer can be maintained, and the excellent heat-sealing properties and film-forming properties required for a sealant layer can be maintained.

The inorganic porous material carrying the chemical adsorbent may have any external shape, such as a sphere, a rod, or an ellipse, and may be in any form, such as a powder, a lump, or a granule. From the viewpoints of the above-mentioned film-forming properties, uniform dispersibility, kneading properties, etc., a powder form is preferred.

The average particle size of the chemical adsorbent-supporting inorganic porous material can be appropriately selected depending on the application, but in the present invention, the average particle size is preferably 0.01 μm to 15 μm, more preferably 0.1 μm to 13 μm, and even more preferably 1 μm to 12 μm. Here, the average particle size is a value measured by dynamic light scattering.
If the average particle size is smaller than the above range, the chemical adsorbent-supporting inorganic porous material is likely to aggregate, and dispersibility tends to decrease.
If the average particle size is larger than the above range, the film-forming properties will be poor, making it difficult to incorporate a large amount of the chemical adsorbent-supporting inorganic porous material, and there is a possibility that a sufficient adsorption effect will not be obtained.
Specific examples of commercially available products that can be used as suitable odor adsorbents in the present invention include NS-241 and NS-231 (amino group-containing compound-supported inorganic porous material) manufactured by Toagosei Co., Ltd., and Dashlite M (amino group-containing compound-supported inorganic porous material) and Dashlite CZU (copper oxide and zinc oxide-supported inorganic porous material) manufactured by Sinanen Zeomic Co., Ltd.

The mechanism by which the chemical adsorbent-supporting inorganic porous material adsorbs odorous substances will be explained in more detail using specific examples shown in Figs. 4(a) and (b), but the present invention is not limited to these.
For example, Fig. 4(a) shows a case where a carboxylic acid odorant is chemically adsorbed to a hydroxyl group-supported inorganic porous body. The carboxyl group of the carboxylic acid odorant and the hydroxyl group of the hydroxyl group-supported inorganic porous body undergo a chemical reaction to bond, and the carboxylic acid odorant is adsorbed.
4(b) shows a case where an aldehyde odorant is chemically adsorbed to an amino group-supported inorganic porous material. The aldehyde group of the aldehyde odorant and the amino group of the amino group-supported inorganic porous material undergo a chemical reaction to bond, and the aldehyde odorant is adsorbed.

Since the chemical adsorbent-supporting inorganic porous material employs chemical adsorption, odorous substances once adsorbed are unlikely to be desorbed, and odor adsorption can be carried out efficiently.
Furthermore, since the odorants bind to specific functional groups of the chemical adsorbent, it is less susceptible to the effects of various substances that reduce odor adsorption capacity, such as water vapor.

(Amino group-supported inorganic porous material)
The amino group-supported inorganic porous material is an inorganic porous material having amino groups supported on the surface, and is capable of chemically adsorbing odorous substances that chemically react with the amino groups.
The amino group-supporting inorganic porous material can be prepared, for example, by using a compound containing an amino group.
Examples of compounds containing an amino group include alkylamines, cyclic amines, polyamines, and alcohol amines, such as ethylenediamine, tetramethylenediamine, metaphenylenediamine, diethylenetriamine, triethylenetriamine, tetraethylenepentamine, ethanolamine, piperazine, and piperidine.
The amino group-supported inorganic porous material has excellent adsorption performance for aldehydes and ketones.
Aldehydes and ketones react chemically with amino groups via the Schiff reaction and are adsorbed.

(Hydroxyl Group-Supported Inorganic Porous Material)
The hydroxyl group-supporting inorganic porous material is an inorganic porous material that supports hydroxyl groups on the surface, and is capable of chemically adsorbing odorous substances that chemically react with hydroxyl groups.
The hydroxyl group-supporting inorganic porous material can be prepared, for example, by using a compound containing a hydroxyl group.
Examples of compounds containing a hydroxyl group include metal hydroxides, such as sodium hydroxide, potassium hydroxide, magnesium hydroxide, and iron hydroxide.
The hydroxyl group-supporting inorganic porous material has excellent adsorption performance for carboxylic acids and amines.

(Metal-supported inorganic porous material)
The metal-supported inorganic porous material is an inorganic porous material that supports a metal element in the state of metal, metal ion, or metal oxide.
The metal species to be supported preferably contains one or more metals selected from the group consisting of copper, zinc, silver, platinum, iron and cobalt.
In the present invention, by using a metal-supported inorganic porous material, the adsorption capacity per unit mass of the odor adsorbent can be significantly increased, and the content in the laminate can be reduced. In addition, physical adsorption properties for the pores of the inorganic porous material can also be expected.
Furthermore, the metal-supported inorganic porous material may have any external shape, such as a spherical shape, a rod shape, an elliptical shape, or the like, and may be in any form, such as a powder shape, a lump shape, or a granular shape. From the viewpoints of the above-mentioned film-forming properties, uniform dispersibility, kneading properties, and the like, the powder shape is preferred.

The metal-supported inorganic porous material can be appropriately selected from those having any average particle size depending on the application, but in the present invention, those having an average particle size of 0.01 μm to 15 μm are particularly preferred, those having an average particle size of 0.1 μm to 13 μm are more preferred, and those having an average particle size of 1 μm to 12 μm are even more preferred. Here, the average particle size is a value measured by dynamic light scattering.
If the average particle size is smaller than the above range, the metal-supporting inorganic porous material is likely to aggregate, and dispersibility tends to decrease.
If the average particle size is larger than the above range, the film-forming properties will be poor, making it difficult to incorporate a large amount of the metal-supported inorganic porous material, and there is a possibility that a sufficient adsorption effect will not be obtained.

(Inorganic porous body used in chemical adsorbent-supporting inorganic porous body)
In the present invention, the inorganic porous material used for the chemical adsorbent-supporting inorganic porous material may be any inorganic compound having a large number of pores on its surface. Examples of such materials include zeolites, silicon dioxide, silicates, activated carbon, titania, inorganic phosphates such as calcium phosphate, alumina, aluminum hydroxide, magnesium hydroxide, and mixtures thereof. In particular, it is preferable to use aluminum hydroxide, zeolites, and silicates, which have a porous state with pore sizes that are effective for the molecular size or cluster size of the substance to be adsorbed, and which have a safety aspect.
In the above, the zeolite is preferably hydrophobic, and more preferably has a SiO ₂ /Al ₂ O ₃ molar ratio of 400/1 to 10,000/1.
In particular, it is preferable to use aluminum hydroxide, zeolite, and silicates, because they have a porous state with pores of an effective size relative to the molecular size or cluster size of the substance to be adsorbed, and from the standpoint of safety.

The external shape of the inorganic porous body may be any shape, such as a spherical shape, a rod shape, an ellipse shape, or the like, and may be in any form, such as a powder shape, a lump shape, or a granular shape. However, from the viewpoints of the above-mentioned film-forming properties, uniform dispersion, kneading properties, and the like, after the chemical adsorbent is supported to form the inorganic porous body supported by the chemical adsorbent, the powder shape is preferred.
The inorganic porous body can be appropriately selected from those having any average particle size depending on the application. In order to achieve the average particle size of the above-mentioned chemical adsorbent-supporting inorganic porous body, the average particle size is preferably 0.01 μm to 15 μm, more preferably 0.1 μm to 13 μm, and even more preferably 1 μm to 12 μm.

(Improved dispersion by making odor adsorbents into master batches)
The odor adsorbent may be directly mixed with other components of the odor adsorbing sealant layer, such as a heat-sealable resin, and melt-kneaded, but it is preferable to increase the dispersibility of the odor adsorbent in the odor adsorbing sealant layer by mixing the odor adsorbent with a thermoplastic resin at a high concentration and then melt-kneading (melt blending) to prepare a master batch, and then mixing this with other components of the odor adsorbing sealant layer in a ratio corresponding to the target content, and melt-kneading the master batch.
By employing the master batch method, even when an odor adsorbent that is prone to aggregation is used, the odor adsorbent can be efficiently and uniformly dispersed in the odor adsorbing sealant layer.

The mass ratio of the gas adsorbent to the thermoplastic resin in the master batch is not particularly limited, but is preferably from 0.5/99.5 to 40/60, and more preferably from 1/99 to 35/65.
As a method for kneading the odor adsorbent and the thermoplastic resin, a known or commonly used kneading method can be applied.
The thermoplastic resin used in the masterbatch may be of a type and content within a range that does not significantly adversely affect the heat sealability, film formability, odor adsorption properties, or low elution properties of the entire odor adsorbing sealant layer.

The MFR (melt flow rate) of the thermoplastic resin is preferably 0.2 g/10 min or more and 10 g/10 min or less. If the MFR is in this range, melt mixing with the odor adsorbent is easy, the odor adsorbent can be easily dispersed in the odor adsorbing sealant layer, and the film-forming properties of the odor adsorbing sealant layer can be easily maintained.

Specific examples of the thermoplastic resin include polyolefin resins such as general-purpose polyethylene, polypropylene, methylpentene polymer, and acid-modified polyolefin resins, and mixtures of these resins, but are not limited to these resins, and the type of thermoplastic resin can be selected depending on the purpose.
It is also possible and preferred to use the heat-sealable resin contained in the odor-adsorbing sealant layer as the thermoplastic resin.

[Heat sealable resin]
Examples of the heat-sealable resin contained in the odor-adsorbing sealant layer include polyolefins, olefin-based copolymers, copolymers of olefins and vinyl compounds, copolymers of olefins and various (meth)acrylic compounds, copolymers of olefins and unsaturated carboxylic acids, ionomer resins, terpolymer resins of olefins, various (meth)acrylic compounds, and various unsaturated carboxylic acids, polyethylene terephthalate (PET), polyacrylonitrile (PAN), etc. These may be used alone or in combination of two or more.
Among the above, polyolefins and olefin-based copolymers are preferred from the viewpoint of heat sealability, and olefin-based copolymers are more preferred.

(Polyolefin)
In the present invention, the polyolefin is a resin whose main chain is composed of repeating units derived from one or more types of monomers.
Examples of the polyolefin include polyethylene, polypropylene, methylpentene polymer, and cyclic polyolefin resin. Examples of the polyethylene include low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (MDPE), linear low-density polyethylene (LLDPE), and metallocene polyethylene. These may be used alone or in combination of two or more. Among the above polyolefins, LLDPE is particularly preferred.
Furthermore, among LLDPEs, it is preferable to use one or more types selected from the group consisting of C4-LLDPE, C6-LLDPE, and C8-LLDPE, each having a density of 0.90 g/ ^cm3 or more and 0.94 g/cm3 ^or less. If the density is lower than the above range, the film surface may become sticky and blocking may easily occur, resulting in a decrease in manufacturability, whereas if the density is higher than the above range, the flexibility of the film may decrease, resulting in an increase in the number of pinholes.

(Vinyl compounds)
The vinyl compound is a compound having a vinyl group, and specific examples thereof include vinyl acetate, vinyl alcohol, etc., and various (meth)acrylic compounds include (meth)acrylic acid, (meth)acrylic acid esters, etc. These may be used alone or in combination of two or more.

(Unsaturated Carboxylic Acid)
The unsaturated carboxylic acid is a carboxylic acid having an unsaturated carbon-carbon bond, and specific examples thereof include maleic acid, fumaric acid, and anhydrides thereof. These may be used alone or in combination of two or more.

<Base layer>
In the present invention, the base layer is a layer that imparts various properties to the odor-adsorbing laminate, such as imparting rigidity to the odor-adsorbing laminate, gas barrier properties, light-shielding properties, strength, etc.
The properties to be imparted depend on the type of contents to be packaged, as well as the mechanical strength, chemical resistance, solvent resistance, manufacturability, and other properties required in logistics, and various materials can be used.
The substrate layer preferably contains a thermoplastic resin, and more preferably uses a resin film obtained by filming a thermoplastic resin. For example, a known or commercially available film having gas barrier properties, light shielding properties, and high strength can be used. The film may be unstretched, uniaxially stretched, or biaxially stretched.
The base layer may also be made of a metal foil such as an aluminum foil.

When it is desired to improve the gas barrier properties of the odor-adsorbing laminate, it is preferable to use a silica-vapor-deposited film, an aluminum oxide-vapor-deposited film, or an aluminum foil, and the laminate can be produced by forming a silica-vapor-deposited film, an aluminum oxide-vapor-deposited film, etc. on at least one side of the above-mentioned resin film.
When it is desired to increase the strength of the odor-adsorbing laminate, a film having high strength can be used, and specifically, it is preferable to use a film made of PET, polybutylene terephthalate, or the like.
When it is desired to improve the light-shielding properties of the odor-adsorbing laminate, it is preferable to use aluminum foil.

Examples of the thermoplastic resin used in the base layer include polyethylene resins, polypropylene resins, cyclic polyolefin resins, polyvinyl alcohol, ethylene-vinyl alcohol copolymers, fluorine resins, polystyrene resins, acrylonitrile-styrene copolymers (AS resins), acrylonitrile-butadiene-styrene copolymers (ABS resins), polyvinyl chloride resins, fluorine resins, poly(meth)acrylic resins, polycarbonate resins, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate, polyamide (nylon) resins such as polyamide 6, polyamide 11, polyamide 12, polyamide 66, polyamide 610, polyamide 6T, polyamide 6I, polyamide 9T, polyamide M5T, and polyamide 6/66, polyimide resins, polyamideimide resins, polyarylphthalate resins, silicone resins, polysulfone resins, polyphenylene sulfide resins, polyethersulfone resins, polyurethane resins, acetal resins, and cellulose resins. Among the above, polyethylene terephthalate (PET) and polyamide (nylon) resins are preferred.
The substrate layer preferably contains one or more resins selected from the above, and may be composed of one layer or two or more layers having the same composition or different compositions.

The substrate layer in the present invention is preferably capable of imparting appropriate rigidity and gas barrier properties to the odor-adsorbing laminate. For example, an alumina-deposited PET film is preferred, and an alumina-deposited PET film with a barrier coat resin layer is more preferred.
stomach.

The thickness of the base layer can be appropriately determined by a person skilled in the art depending on the packaging application, but is preferably 6 μm or more and 150 μm or less, and more preferably 9 μm or more and 130 μm or less. In particular, when a resin film with a vapor deposition layer is used, it is even more preferable that the thickness be 10 μm or more and 50 μm or less.

The base layer may contain various modifying resins, plastic compounding agents, additives, etc., for the purpose of improving or modifying the processability, heat resistance, weather resistance, mechanical properties, dimensional stability, oxidation resistance, slipperiness, release properties, flame retardancy, mold resistance, electrical properties, strength, etc., of the odor-adsorbing laminate. In this case, these additives may be optionally contained in the base layer in amounts ranging from trace amounts to several tens of mass % depending on the purpose. In the present invention, general additives that may be optionally contained include lubricants, crosslinking agents, antioxidants, UV absorbents, light stabilizers, fillers, antistatic agents, lubricants, antiblocking agents, colorants such as dyes and pigments, etc.

In the present invention, the substrate layer may be a single layer or a multilayer film formed using a film forming method such as an extrusion method, a cast molding method, a T-die method, a cutting method, or an inflation method.

If necessary, it is preferable to subject the surface of the base layer to various surface treatments before lamination. Examples of surface treatments include corona treatment and ozone treatment.

<Adhesive Layer>
In the present invention, it is also possible to laminate the layers by providing an adhesive layer between the layers constituting the laminate and between layers within each layer.
Furthermore, before forming the adhesive layer, an anchor coat layer may be formed in advance on the surface of the layer to be adhered in order to improve adhesion.

The adhesive (adhesive composition) forming the adhesive layer may be of a heat-curing type, an ultraviolet-curing type, an electron beam-curing type, or the like, and may be in any form such as an aqueous type, a solution type, an emulsion type, a dispersion type, or the like. In addition, the adhesive may be in any form such as a film/sheet type, a powder type, a solid type, or the like, and the adhesive mechanism may be in any form such as a chemical reaction type, a solvent volatilization type, a thermal melting type, a thermal pressure type, or the like.
Examples of such adhesives include polyvinyl acetate adhesives such as polyvinyl acetate and vinyl acetate-ethylene copolymers, polyacrylic acid adhesives consisting of copolymers of polyacrylic acid and polystyrene, polyester, polyvinyl acetate, etc., cyanoacrylate adhesives, ethylene copolymer adhesives consisting of copolymers of ethylene and monomers such as vinyl acetate, ethyl acrylate, acrylic acid, methacrylic acid, etc., cellulose adhesives, polyurethane adhesives, polyester adhesives, polyamide adhesives, polyimide adhesives, polyolefin adhesives, amino resin adhesives consisting of urea resin or melamine resin, etc., phenol resin adhesives, epoxy adhesives, reactive (meth)acrylic adhesives, elastomer adhesives consisting of chloroprene rubber, nitrile rubber, styrene-butadiene rubber, etc., silicone adhesives, inorganic adhesives consisting of alkali metal silicates, low melting point glass, etc.

In one embodiment of the present invention, the adhesive layer may be a layer made of any of an adhesive for EC (extrusion coating), an adhesive for dry lamination, an adhesive for non-solvent lamination, and the like.
When an EC adhesive is used, although there are no particular limitations, for example, the adhesive is first heated and melted, expanded and stretched in the required width direction using a T-die or the like, extruded into a curtain shape, allowed to flow down onto the layer to be adhered, and then sandwiched between a rubber roll and a cooled metal roll, thereby simultaneously forming an adhesive layer and adhering and laminating to the layer to be adhered.

In another embodiment, the adhesive layer may be formed by sand lamination. In this case, the adhesive layer may be made of any resin that can be applied by heating and melting it in an extruder. Specifically, the resins listed above as thermoplastic resins having heat sealability can be preferably used.

When using a dry lamination adhesive, the adhesive dispersed or dissolved in a solvent is applied to one film and dried, and the other film is then placed on top of it to laminate. The adhesive is then cured by aging at 30 to 120°C for several hours to several days to bond and laminate the films together.

When using a non-solvent laminating adhesive, the adhesive itself is applied to the layer to be adhered without being dispersed or dissolved in a solvent, and then dried. The film that will form the other layer is then layered on top of it, and the adhesive is then aged at 30 to 120°C for several hours to several days to harden the adhesive and laminate it.

The adhesive for dry lamination or the adhesive for non-solvent lamination can be used by coating, for example, by roll coating, gravure roll coating, kiss coating, etc., and the coating amount is preferably 0.1 to 10 g/ ^m2 (dry state). By setting the coating amount within the above range, good adhesion can be obtained.

(Anchor coat layer)
The anchor coat layer can be formed from any anchor coat agent.
Examples of anchor coating agents that can be used include organic titanium-based, isocyanate (urethane-based), polyethyleneimine-based, acid-modified polyethylene-based, polybutadiene-based, polyacrylic-based, polyester-based, epoxy-based, polyvinyl acetate-based, cellulose-based, and other anchor coating agents.

<<Odor-absorbing packaging material>>
The odor-adsorbing packaging material of the present invention is a packaging material made from the odor-adsorbing laminate of the present invention, and may be the same as the odor-adsorbing laminate, and may further include various functional layers, printed layers, etc., as necessary.
The odor-absorbing packaging material of the present invention can also be subjected to lamination (dry lamination or extrusion lamination), bag making, and other post-treatment processes.

[Method of producing odor-adsorbing laminate or odor-adsorbing packaging material]
For example, an example of the production of an odor-adsorbing laminate (packaging material) having a layer structure of substrate layer/adhesive layer/odor-adsorbing sealant layer (heat seal layer/odor-adsorbing layer/heat seal layer) will be described.
The preparation method described below is merely an example and is not intended to limit the present invention.
As long as the layers are laminated in this order, the order in which the layers are formed and laminated may be arbitrary.
First, a heat sealable resin and a resin composition for an odor adsorbing layer are laminated by inflation film formation to obtain an odor adsorbing sealant film having a layer structure of heat seal layer/odor adsorbing layer/heat seal layer.
Next, an adhesive layer is formed on one of the corona-treated surfaces of the base layer resin film using an adhesive for dry lamination or the like.
Then, the adhesive layer with the resin film for base layer obtained above is laminated facing the odor-absorbing sealant film.
Next, an aging treatment is carried out as necessary.
In this manner, an odor absorbing laminate or odor absorbing packaging material can be made.

The lamination of each layer described above can be carried out by any method used in the production of ordinary packaging materials, such as a wet lamination method, a dry lamination method, a solventless dry lamination method, an extrusion lamination method, a T-die coextrusion molding method, a coextrusion lamination method, an inflation method, or the like.
The odor-adsorbing laminate or odor-adsorbing packaging material obtained above can be subjected to secondary processing for the purpose of imparting surface functions such as chemical functions, electrical functions, magnetic functions, mechanical functions, friction/wear/lubrication functions, optical functions, thermal functions, biocompatibility, etc.
Examples of secondary processing include embossing, painting, adhesive, printing, metallizing (plating, etc.), machining, surface treatment (antistatic treatment, corona discharge treatment, plasma treatment, photochromic treatment, physical vapor deposition, chemical vapor deposition, coating, etc.), and the like.

<<Odor-absorbing packaging material>>
The odor-adsorbing package of the present invention is a package made using the odor-adsorbing packaging material of the present invention.

[Method of producing odor-absorbing packaging material]
As an example of a method for producing an odor-adsorbing package, a method for producing a packaging bag by forming an odor-adsorbing packaging material into a bag will be given.
First, the odor-absorbing packaging material is folded or two sheets are overlapped so that the odor-absorbing sealant layers of the odor-absorbing packaging material face each other, and the peripheral edges are heat-sealed to prepare the odor-absorbing packaging material.
Examples of the shape of the packaging bag include side seal type, two-sided seal type, three-sided seal type, four-sided seal type, envelope seal type, palm seal type (pillow seal type), pleated seal type, flat bottom seal type, square bottom seal type, and gusset type.
As the heat sealing method, for example, known methods such as bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing, ultrasonic sealing, etc. can be used.

<Ingredients>
Details of the raw materials used in the examples are as follows.
[Film for base layer]
Barrier substrate film 1: IB-PET-PIR manufactured by Dai Nippon Printing Co., Ltd. Alumina-deposited PET film with a barrier coat resin layer. Thickness: 12 μm.

[Heat sealable resin]
Heat sealable resin 1: Ultzexx 1520L, manufactured by Prime Polymer Co., Ltd. C6-LLDPE, density 0.916 g/cm ³ , MFR 2.3 g/10 min.
Heat sealable resin 2: manufactured by Ube Maruzen Polyethylene Co., Ltd., Yumerit 720FT, C4-LLDPE, density 0.918 g/cm ³ , MFR 4 g/10 min.
Heat sealable resin 3: Ube Maruzen Polyethylene Co., Ltd., Yumerit 125NF, HAO-LLDPE (copolymerized LLDPE using higher α-olefins having 6 or more carbon atoms such as C6 and C8 as comonomers), density 0.924 g/cm ³ , MFR 2.2 g/10 min.;
Heat sealable resin 4: manufactured by Prime Polymer Co., Ltd., Hi-Zex 3300F, density 0.949 g/cm ³ , MFR 1.1 g/10 min.

[Odor absorbent]
Hydrophobic zeolite 1: Silton MT400, a hydrophobic zeolite manufactured by Mizusawa Chemical Industry Co., Ltd. SiO ₂ /Al ₂ O ₃ molar ratio = 400/1, average particle size = 5 to 7 μm.
Hydrophobic zeolite 2: Silton MT-8000, a hydrophobic zeolite manufactured by Mizusawa Chemical Industry Co., Ltd. _{SiO 2} /Al ₂ O ₃ molar ratio = 8000/1, average particle size = 0.8 μm.
General-purpose zeolite 1: Mizuka Sieves 5AP, a zeolite manufactured by Mizusawa Chemical Industries, Ltd. _{SiO 2} /Al ₂ O ₃ molar ratio = 2/1, average particle size 5 μm.
- Amino group-supporting inorganic porous material 1: Kesmon NS-241 manufactured by Toagosei Co., Ltd. Average particle size 3.5 μm.
- Hydroxyl group-supporting inorganic porous material 1: Kesmon NS-80E, manufactured by Toagosei Co., Ltd. Average particle size: 2 μm.
Metal-supported inorganic porous body 1: Dashlight CZU, manufactured by Sinanen Zeomic Co., Ltd. CuO, ZnO-supported zeolite, average particle size = 3 to 5 μm.

[glue]
DL Adhesive 1: Adlock RU004/H1, manufactured by Rock Paint Co., Ltd. Polyester adhesive

<Preparation and Evaluation of Laminate>
[Preparation of Masterbatch]
The masterbatch used in the odor absorbing sealant layer was prepared as follows.
(Preparation of Masterbatch 1)
Heat-sealable resin 1 and hydrophobic zeolite 1 were melt-blended in the following ratio to obtain master batch 1 (MB1).
Heat sealable resin 1 70 parts by weight Hydrophobic zeolite 1 30 parts by weight

[Preparation of Masterbatches 2 to 6]
According to the formulations in Table 1, melt blending was carried out in the same manner as for Masterbatch 1 to obtain Masterbatches 2 to 6 (MB2 to 6).

[Preparation of odor-adsorbing sealant layer resin composition]
By dry blending the raw materials in the compositions shown in Tables 2 and 3, odor-adsorbing sealant layer resin compositions 1 to 18 were obtained.

Example 1
The odor absorbing sealant layer resin composition 1 and heat sealable resin 1 obtained above were laminated by inflation film formation at 160° C. to obtain an odor absorbing sealant film 1 having the following three-layer structure.
Layer structure of odor adsorbing sealant film 1: heat seal layer/odor adsorbing layer/heat seal layer=heat sealable resin 1 (10 μm)/odor adsorbing sealant layer resin composition 1 (30 μm)/heat sealable resin 1 (10 μm).

Next, the odor-adsorbing sealant film 1 and barrier substrate film 1 obtained above were bonded together by dry lamination (coating amount: 3.5 g/ ^m2 , drying temperature: 70°C) using DL adhesive 1 to obtain an odor-adsorbing laminate 1 having the following layer structure.
The odor-adsorbing laminate 1 thus obtained was subjected to various evaluations.
Structure of odor-adsorbing laminate 1: substrate layer/adhesive layer/odor-adsorbing sealant layer [heat seal layer/odor-adsorbing layer/heat seal layer] = barrier substrate film 1 (12 μm)/DL adhesive 1 (coating amount: 3.5 g/m ² )/odor-adsorbing sealant layer (50 μm) [heat-sealable resin 1 (10 μm)/odor-adsorbing layer resin composition 1 (30 μm)/heat-sealable resin 1 (10 μm)]

<Examples 2 to 18, Comparative Examples 1 to 3>
Using the raw materials shown in Tables 4 to 7, the same procedures as in Example 1 were carried out to obtain odor-adsorbing laminates, which were then similarly evaluated.

<Summary of results>
All of the odor-adsorbing laminates of the present invention exhibited a balance of heat sealability, good adsorption to odorous substances, and good low odor properties.
The laminate of Comparative Example 1, which contained general-purpose zeolite instead of hydrophobic zeolite, showed insufficient odor adsorption performance. The laminate of Comparative Example 2, which did not contain an odor-adsorbing sealant layer, showed poor adsorption properties for odorous substances and low odor properties, and Comparative Example 3, which contained a high concentration of odor adsorbent, showed good adsorption properties for odorous substances and low odor properties, but showed poor film-forming properties.

<Evaluation method>
[Film-forming ability]
The appearance of the odor-adsorbing laminate was observed and evaluated sensorily according to the following criteria:
◯: A film can be formed without wrinkles or bumps occurring in the odor-adsorbing laminate.
×: Numerous wrinkles and bumps were generated in the odor-adsorbing laminate, making film formation difficult.

[Heat sealability]
The odor-absorbing laminate was cut into a piece of 10 cm x 10 cm, the odor-absorbing sealant layer faces were overlapped, and a 1 cm x 10 cm area was heat-sealed under the following conditions using a heat seal tester (TP-701-A manufactured by Tester Sangyo Co., Ltd.), with the ends not being heat-sealed or bonded, and being divided into two, to prepare a test piece for peel strength.
This test piece was cut into a strip of 15 mm width, and each bifurcated end was attached to a tensile tester to measure the peel strength (N/15 mm) under the conditions described below, and the pass/fail judgment was made according to the pass/fail judgment criteria described below.
Heat sealing conditions Temperature: 160°C
Pressure: 1 kgf/ ^cm2
Time: 1 second Test conditions Test speed: 300 mm/min Load range: 50 N
Pass/fail criteria: ◯: 30N/15mm or more, passed.
×: Less than 30N/15mm, not acceptable.

[Odor adsorption]
The odor adsorbing laminate was cut into a piece of 20 x 20 cm and placed in a gas sampling bag (GL Sciences Inc., SMART BAG PA AKK-10, pouch area A4 size). Furthermore, the gas sampling bag was filled with 1000 ml of a test mixed gas adjusted to 100 ppm acetaldehyde, 50 ppm acetic acid, and 200 ppm ethanol, and then sealed.
Then, the concentration of each gas component was measured after leaving it in a room temperature environment for 48 hours.
Acetaldehyde concentration: detector tube (Gastec Corporation, No. 92M)
Acetic acid concentration: detector tube (Gastec Corporation, No. 81)
Ethanol: detector tube (Gastec Corporation, No. 112L)

Reference Signs List 1: odor-adsorbing laminate 2: substrate layer 3: odor-adsorbing sealant layer 3a: heat seal layer 3b: odor-adsorbing layer 4: adhesive layer 10: chemical adsorbent-carrying inorganic porous body

Claims (5)

An odor-adsorbing laminate capable of adsorbing any one of four odorous substances, namely, aldehydes, ketones, carboxylic acids, and alcohols,
The odor-adsorbing laminate was cut into pieces of 20 x 20 cm and placed in a gas sampling bag. The gas sampling bag was then filled with 1,000 ml of a test mixed gas containing 100 ppm acetaldehyde, 50 ppm acetic acid, and 200 ppm ethanol, and sealed. After leaving the bag in an ambient temperature environment for 48 hours, in order to reduce the concentration of the ethanol gas component to 70 ppm or less,
The odor-absorbing laminate includes at least a substrate layer and an odor-absorbing sealant layer,
the substrate layer is an alumina-deposited PET film or an alumina-deposited PET film with a barrier coat resin layer;
the odor-absorbing sealant layer is a layer formed from an odor-absorbing sealant film containing an odor adsorbent and a heat-sealable resin;
the odor-adsorbing sealant layer includes a heat seal layer and an odor-adsorbing layer, the heat seal layer being a layer containing the heat sealable resin and not containing the odor adsorbent, and the odor adsorbing layer being a layer containing the odor adsorbent;
The thickness of the odor adsorption sealant layer is 30 μm or more and 150 μm or less,
The heat-sealable resin contains one or two types of resins selected from the group consisting of C4-LLDPE and C8-LLDPE, each having a density of 0.90 g/ ^cm3 or more and 0.94 g/cm3 ^or less,
The odor adsorbent comprises a hydrophobic zeolite having a _SiO2 / _{Al2O3 molar} ratio of 400/1 to 10,000/1;
The odor adsorbent further comprises one or more members selected from the group consisting of a metal-supported inorganic porous material, an amino group-supported inorganic porous material, and a hydroxyl group-supported inorganic porous material;
The odor-adsorbing laminate has a content of the hydrophobic zeolite in the odor-adsorbing sealant layer of 2.5% by mass or more and 15% by mass or less. 2. The odor-adsorbing laminate according to claim 1 , wherein the odor adsorbent is melt-kneaded in advance with a heat-sealable resin in a mass ratio of odor adsorbent/heat-sealable resin of 0.5/99.5 to 40/60. The odor-adsorbing laminate is
Base layer/heat seal layer/odor adsorption layer,
Base layer/odor absorbing layer/heat seal layer,
Base layer/heat seal layer/odor adsorption layer/heat seal layer,
3. The odor-adsorbing laminate according to claim 1 , wherein the odor-adsorbing laminate is laminated in any one of the following configurations: An odor-adsorbing packaging material produced using the odor-adsorbing laminate according to any one of claims 1 to 3 . 5. An odor-absorbing package made from the odor-absorbing packaging material of claim 4 .

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