JP7059648B2 - Multi-layer sheets, trays and packaging - Google Patents

Description

The present invention relates to multilayer sheets, trays and packages.

Conventionally, as packaging materials for pharmaceuticals, medical products, foods, beverages and the like, paper, synthetic resin sheets or films, thin-film vapor deposition films, laminates with synthetic resin films, aluminum packaging and the like have been used. When used in the above applications, it has characteristics that require protection against water vapor and oxygen, especially barriers to water vapor and oxygen, and high barriers are required to protect the contents over the long term. ing.

Examples of those satisfying both the water vapor barrier property and the oxygen barrier property as described above include a vapor-deposited film and aluminum packaging. However, although these can be used as a specific package such as a pouch shape, it is difficult to mold them into an arbitrary shape with a molding machine or the like, and the usage is limited.

On the other hand, as a form of a packaging container, a packaging form in which a sheet made of synthetic resin is used as a bottom material and then a film and an aluminum foil are heat-sealed as a lid material is often used. As the synthetic resin sheet as the bottom material, a polyolefin-based resin having excellent moldability, productivity, chemical resistance, and water vapor barrier property is particularly used.

However, the polyolefin-based resin is excellent in water vapor barrier property, but inferior in oxygen barrier property. Therefore, various problems such as oxidation, deterioration, putrefaction, or rusting of the contents may occur.

In order to solve the above problem, for example, Patent Document 1 contains a layer containing a resin having an excellent oxygen barrier property such as an ethylene-vinyl alcohol copolymer and nylon, and a resin having an excellent water vapor barrier property such as a polyolefin. A resin laminate comprising a layer is disclosed.

Special Fair No. 06-015227 Gazette

However, the resin laminate disclosed in Patent Document 1 has a problem that the oxygen barrier property and the water vapor barrier property are not sufficient. In particular, in some applications such as medical use, the actual situation is that further water vapor barrier properties are required.

Further, the resin laminate disclosed in Patent Document 1 has a problem that cracks occur due to an impact, and improvement in impact resistance has been required.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a multilayer sheet having excellent oxygen barrier property and water vapor barrier property, and also having excellent impact resistance.

Another object of the present invention is to provide a tray and a package having excellent oxygen barrier property and water vapor barrier property and also excellent impact resistance.

In order to achieve the above object, the present invention has adopted the following configuration.

[1] A multi-layer sheet having a water vapor barrier layer, an oxygen barrier layer, and a pair of surface layers, wherein the surface layers are laminated on both sides of the outermost surface layer, and the water vapor barrier layer and the pair. The surface layer contains high-density polyethylene, and the water vapor permeation amount of the multilayer sheet under the conditions of 40 ° C. and 90% RH measured by the cup method specified in JIS-Z 0208 is 0.15 (g / g / g /. A multi-layer sheet having m ² · day) or less.
[2] The multilayer sheet according to [1], wherein the water vapor barrier layer comprises only high-density polyethylene or contains a mixture of high-density polyethylene and petroleum resin.
[3] The multilayer sheet according to [2], wherein the petroleum resin is a polymer obtained by using dicyclopentadiene.
[4] The multilayer sheet according to any one of [1] to [3], wherein at least one surface layer and the water vapor barrier layer are laminated adjacent to each other.
[5] The multilayer sheet according to any one of [1] to [4], wherein the surface layer comprises only high-density polyethylene or contains a mixture of high-density polyethylene and polypropylene.
[6] The multilayer sheet according to any one of [1] to [5], which has two water vapor barrier layers and the water vapor barrier layer is laminated adjacent to the surface layer.
[7] The multilayer sheet according to any one of [1] to [6], wherein the thickness of the multilayer sheet is 500 μm or more and 1500 μm or less.
[8] The multilayer sheet according to any one of [1] to [7], wherein the tensile impact strength is 110 kJ / m ² or more.
[9] The multilayer sheet according to any one of [1] to [8], wherein the impact strength of the DuPont type drop impact tester is 1.5 J or more.
[10] The multilayer sheet according to any one of [4] to [9], wherein the peel strength between the surface layer and the water vapor barrier layer is 11 N / 15 mm or more.
[11] The multilayer sheet according to any one of [1] to [10], wherein the oxygen permeation amount under the conditions of 25 ° C. and 60% RH is 0.35 cc / m ² · day or less.
[12] A tray formed from the multilayer sheet according to [1].
[13] A package comprising the tray according to [12] and a lid material.

The multilayer sheet of the present invention has a water vapor barrier layer, an oxygen barrier layer, and a pair of surface layers, and the surface layers are laminated on both sides of the outermost surface layer, respectively, and the water vapor barrier layer and the pair. The surface layer contains high-density polyethylene, and the water vapor permeation amount of the multilayer sheet under the conditions of 40 ° C. and 90% RH measured by the cup method specified in JIS-Z 0208 is 0.15 (g / g / g / g /. Since it is m ² · day) or less, it is excellent in oxygen barrier property and water vapor barrier property, and is also excellent in impact resistance.

Further, since the tray of the present invention is obtained by secondary molding the above-mentioned multilayer sheet, it is excellent in oxygen barrier property and water vapor barrier property, and is also excellent in impact resistance.

Further, since the package of the present invention includes the tray and the lid material, it is excellent in oxygen barrier property and water vapor barrier property, and is also excellent in impact resistance.

It is sectional drawing which shows the structure of the multilayer sheet which is one Embodiment to which this invention is applied. It is sectional drawing which shows the structure of the package which is one Embodiment to which this invention is applied.

Hereinafter, a multilayer sheet according to an embodiment to which the present invention is applied, a tray obtained by secondary molding the multilayer sheet, and a package provided with the tray will be described in detail. In addition, in the drawings used in the following explanation, in order to make the features easy to understand, the featured parts may be enlarged for convenience, and the dimensional ratios of each component may not be the same as the actual ones. not.

<Multi-layer sheet>
First, an example of the configuration of a multilayer sheet according to an embodiment to which the present invention is applied will be described.
FIG. 1 is a schematic cross-sectional view of a multilayer sheet 1 according to an embodiment to which the present invention is applied. As shown in FIG. 1, the multilayer sheet 1 of the present embodiment is roughly configured with an oxygen barrier layer 2, an adhesive layer 3, a water vapor barrier layer 4, and a pair of surface layers 5 and 6. ..
The multilayer sheet 1 of the present embodiment can be used, for example, as a packaging material for pharmaceuticals, pharmaceuticals, infusion preparations, blood products, medical devices, cosmetics, quasi-drugs, foods, beverages, industrial parts, electronic parts and the like. can.

The oxygen barrier layer 2 is a resin layer that suppresses the permeation of oxygen and water vapor, and is provided to impart oxygen barrier properties and water vapor barrier properties to the multilayer sheet 1. Further, when the multilayer sheet 1 is molded into a package, it is possible to suppress the permeation of oxygen and water vapor into and out of the package.

Specific examples of the resin contained in the oxygen barrier layer 2 include ethylene-vinyl alcohol copolymers, polyamides, polyvinyl alcohols, polyacrylonitrile, polyvinylidene chloride and the like. Among these, ethylene-vinyl alcohol copolymer and polyamide are particularly preferable from the viewpoint of film forming property with the water vapor barrier layer 4. The oxygen barrier layer 2 may contain one type of the above resin, or may contain two or more types of the resin. Further, an oxygen absorber may be used as the oxygen barrier layer 2.

The thickness of the oxygen barrier layer 2 is not particularly limited, but specifically, for example, it is preferably 12.5 μm or more and 225 μm or less, and more preferably 12.5 μm or more and 150 μm or less. When the thickness of the oxygen barrier layer 2 is 12.5 μm or more, the oxygen barrier property and the water vapor barrier property can be sufficiently exhibited. Further, since the thickness of the oxygen barrier layer 2 is 225 μm or less, it is easy to mold at the time of container molding, and the elongation as a sheet can be maintained. Further, when the thickness is 12.5 μm or more and 150 μm or less, the above effect can be exhibited more remarkably.

The ratio of the thickness of the oxygen barrier layer 2 is not particularly limited, but specifically, for example, it is preferably 2.5% or more and 15% or less with respect to the total thickness of the multilayer sheet 1. More preferably, it is 5.5% or more and 10% or less. When the ratio of the thickness of the oxygen barrier layer 2 is 2.5% or more with respect to the total thickness of the multilayer sheet 1, the oxygen barrier property and the water vapor barrier property can be sufficiently exhibited. Further, when the ratio of the thickness of the oxygen barrier layer 2 is 15% or less with respect to the total thickness of the multilayer sheet 1, the ratio of the thickness of the water vapor barrier layer 4 can be maintained, and the water vapor barrier property can be maintained. And the oxygen barrier property can be sufficiently expressed. Further, when the ratio is 2.5% or more and 10% or less, the above effect can be obtained more remarkably.

The adhesive layer 3 is provided between the oxygen barrier layer 2 and the water vapor barrier layer 4 in order to bond the oxygen barrier layer 2 and the water vapor barrier layer 4. By laminating the oxygen barrier layer 2, the adhesive layer 3, and the water vapor barrier layer 4 in this order, the oxygen barrier layer 2 and the water vapor barrier layer 4 can be adhered to each other via the adhesive layer 3.

The material of the adhesive layer 3 is not particularly limited as long as it can bond the oxygen barrier layer 2 and the water vapor barrier layer 4. Specific examples thereof include an adhesive resin such as a maleic anhydride-modified olefin, a resin mixed with a resin contained in the oxygen barrier layer 2 and the water vapor barrier layer 4, and the like.

The water vapor barrier layer 4 is a resin layer that suppresses the permeation of water vapor, and is provided to impart water vapor barrier properties to the multilayer sheet 1. The water vapor barrier layer 4 is laminated on both sides of the surface of the oxygen barrier layer 2 with one layer each via the adhesive layer 3. As a result, when the multilayer sheet 1 of the present embodiment is molded into a package, the contents can be protected and the permeation of water vapor into the package can be suppressed. Further, as a result, it is possible to suppress a decrease in oxygen barrier property due to moisture absorption of the oxygen barrier layer 2. Further, since the intermolecular hydrogen bonds of the resin constituting the oxygen barrier layer 2 are prevented from being cleaved by water vapor and the molecular gaps of the resin constituting the oxygen barrier layer 2 can be maintained in a narrow state, the oxygen barrier layer 2 has a water vapor barrier property. Can be expressed.

The water vapor barrier layer 4 contains high density polyethylene. This makes it possible to impart high water vapor barrier properties to the multilayer sheet 1.

In addition to the above high-density polyethylene, the water vapor barrier layer 4 is a polyolefin resin other than high-density polyethylene such as polypropylene, cyclic olefin polymer, and cyclic olefin copolymer; petroleum resin; polyvinyl chloride, polyvinylidene chloride, and polychlorotrifluoro. It may contain a resin or the like containing a halogen atom such as polyethylene.

In the present specification, high-density polyethylene (HDPE) refers to a polyethylene resin having a density in the range of 0.941 g / cm ³ to 0.970 g / cm ³ . Among these, those having a water vapor barrier property of 0.950 g / cm ³ or more are preferable, and those of 0.955 g / cm ³ or more are more preferable.

The multilayer sheet 1 of the present embodiment preferably has a high-density polyethylene content of 60% by mass or more, and 65% by mass or more and 95% by mass, based on the total amount of the resin components contained in the water vapor barrier layer 4. The following is more preferable. When the content of the high-density polyethylene is 60% by mass or more with respect to the total amount of the resin component contained in the water vapor barrier layer 4, high water vapor barrier property can be exhibited. Further, when the content of the high-density polyethylene is 65% by mass or more and 95% by mass or less, the above effect can be obtained more remarkably, and other resin components can be added to add water vapor barrier property to the water vapor barrier layer 4. Properties other than can be imparted.

The water vapor barrier layer 4 may be made of only high-density polyethylene, or may contain a mixture of high-density polyethylene and petroleum resin. By including high-density polyethylene as an essential component in the resin component contained in the water vapor barrier layer 4, it is possible to impart extremely high water vapor barrier properties to the multilayer sheet 1.

Here, the petroleum resin refers to a resin obtained mainly from C5 or _{C9 fractions} among the remaining fractions obtained by thermally decomposing petroleum naphtha and collecting fractions such as ethylene, propylene and butadiene.

As the petroleum resin, an aliphatic type, an aromatic hydrocarbon resin type, an alicyclic saturated hydrocarbon resin type, a copolymerization type and the like can be used, but the aliphatic hydrocarbon resin is used from the viewpoint of transparency and odor. It is preferable, more preferably, a hydrogenated dicyclopentadiene-based petroleum resin obtained by thermally polymerizing dicyclopentadiene and then subjecting it to a hydrogenation reaction. The content ratio of the constituent unit derived from dicyclopentadiene to all the constituent units in the petroleum resin is preferably 30% or more.

The softening point of the petroleum resin (ring ball method, according to JIS K2548) is preferably about 70 to 150 ° C, more preferably 90 to 140 ° C. By setting the softening point to 70 ° C. or higher, the balance between the adhesive performance and the heat resistance of the composition with respect to the polyolefin is improved. It is preferable to set the softening point to 150 ° C. or lower because the resin can be easily manufactured and is advantageous in terms of manufacturing cost.

The number average molecular weight of the petroleum resin is preferably 300 to 2000, more preferably 350 to 1000. By setting the number average molecular weight to the above range or more, the adhesive performance such as the cohesive force of the resin composition is improved, and the water vapor barrier property is also improved. When the number average molecular weight is not more than the above range, the compatibility of the base polymer with the rubber-based polymer or the synthetic resin-based polymer is good, the resin can be easily manufactured, and the manufacturing cost is also advantageous. Therefore, it is preferable. The number average molecular weight is based on the polystyrene conversion value obtained by the gel permeation chromatography (GPC) method.

Specifically, the content of the petroleum resin in the water vapor barrier layer 4 is preferably 40% by mass or less, preferably 5% by mass or more, and 35% by mass with respect to the total mass of the water vapor barrier layer 4. The following is more preferable. When the content of the petroleum resin in the water vapor barrier layer 4 is 40% by mass or less with respect to the total mass of the water vapor barrier layer 4, the water vapor barrier property of the water vapor barrier layer 4 is improved, and the multi-layer sheet 1 as a whole The water vapor barrier property can be dramatically improved. Further, when the content of the petroleum resin in the water vapor barrier layer 4 is 5% by mass or more and 35% by mass or less with respect to the mass of the entire water vapor barrier layer 4, the above effect can be obtained more remarkably.

The water vapor barrier layer 4 contains high-density polyethylene and petroleum in the resin component from the viewpoints of moldability to the multilayer sheet 1, moldability to the package, sealing property with the lid material, adhesiveness to the adjacent layer, and cost. It may contain one or more kinds of resins other than the resin.

The water vapor barrier layer 4 may contain an inorganic filler. Specifically, the content of the inorganic filler in the water vapor barrier layer 4 is preferably 5% by mass or less with respect to the total mass of the water vapor barrier layer 4, for example. When the content of the inorganic filler in the water vapor barrier layer 4 is 5% by mass or less with respect to the total mass of the water vapor barrier layer 4, it is possible to suppress a decrease in impact resistance. Specific examples of the inorganic filler include layered silicates such as talc, mica, montmorillonite, kaolin, clay, bentonite, and hectrite, silica, calcium carbonate, magnesium carbonate, calcium sulfate, magnesium sulfate, and the like. Examples thereof include barium sulfate, glass filler, glass fiber, glass beads, titanium oxide, aluminum oxide, iron, zinc and aluminum.

The thickness of one layer of the water vapor barrier layer 4 is not particularly limited, but specifically, for example, it is preferably 112.5 μm or more and 660 μm or less, and more preferably 125 μm or more and 640 μm or less. When the thickness of one layer of the water vapor barrier layer 4 is 112.5 μm or more, the water vapor barrier property can be sufficiently exhibited. Further, when the thickness of one layer of the water vapor barrier layer 4 is 660 μm or less, the multilayer sheet 1 can be easily formed into a package. Further, when the thickness is 125 μm or more and 640 μm or less, the above effect can be obtained more remarkably.

The ratio of the total thickness of the two layers of the water vapor barrier layer 4 is not particularly limited, but specifically, for example, it may be 45% or more and 87.5% or less with respect to the total thickness of the multilayer sheet 1. It is more preferably 50% or more and more preferably 85% or less. When the ratio of the total thickness of the two layers of the water vapor barrier layer 4 is 45% or more with respect to the total thickness of the multilayer sheet 1, the water vapor barrier property can be sufficiently exhibited as the whole sheet. Further, since the ratio of the total thickness of the two layers of the water vapor barrier layer 4 is 87.5% or less with respect to the total thickness of the multilayer sheet 1, sufficient oxygen barrier property is ensured in addition to the water vapor barrier property. be able to. Further, when the ratio is 50% or more and 85% or less, the above effect can be obtained more remarkably.

Specifically, the water vapor permeation amount of the water vapor barrier layer 4 is preferably 0.6 g / m ² · day or less, preferably 0.55 g / m ² · day or less in an atmosphere of 40 ° C. and 90% RH or less. Is more preferable, and 0.5 g / m ² · day or less is particularly preferable. When the water vapor permeation amount of the water vapor barrier layer 4 is 0.6 g / m ² · day or less in an atmosphere of 40 ° C. and 90% RH, the water vapor permeation amount to the oxygen barrier layer 2 decreases, and the oxygen barrier The deterioration of the oxygen barrier property due to the moisture absorption of the layer 2 is suppressed, and the oxygen barrier layer 2 can sufficiently exhibit the water vapor barrier property. Further, when the water vapor permeation amount is 0.55 g / m ² · day or less and 0.5 g / m ² · day or less, the above effect can be obtained more remarkably.

The water vapor permeation amount of the water vapor barrier layer 4 can be measured according to the method described in JIS-Z 0208 method.

The pair of surface layers 5 and 6 are provided so as to be the outermost layers on both sides of the multilayer sheet 1 in order to impart sealing property, glossiness, and impact resistance to the multilayer sheet 1. Here, the pair of surface layers 5 and 6 are laminated so as to be adjacent to the water vapor barrier layer 4, respectively.

The pair of surface layers 5 and 6 both contain high density polyethylene. Impact resistance and barrier properties can be improved by including at least one of the pair of surface layers 5 and 6 containing high-density polyethylene.

When molding the multilayer sheet 1 into a tray, for example, when the surface layer 5 is provided on the inner side (inner surface), the surface layer 5 exerts a function of imparting a sealing property, so that the sealing strength between the tray and the lid material is increased. At the same time as suppressing the variation, the sealing property can be improved. On the other hand, since the surface layer 6 on the outer side (outer surface) imparts glossiness and impact resistance, the gloss of the tray is improved to give an excellent appearance, and the tray is prevented from cracking due to impact. can do.

The surface layer (hereinafter, also referred to as “inner surface layer”) 5 to be the inner surface may be made of only high-density polyethylene or may contain a mixture of high-density polyethylene and polypropylene, but has a high density. It is preferably made of polyethylene only. By including high-density polyethylene as an essential component in the resin contained in the inner surface layer 5, when the multilayer sheet 1 is molded into a tray, the sealing strength between the tray and the lid material and adjacent to the tray are obtained. Sufficient adhesion to the water vapor barrier layer can be ensured.

In addition to the high-density polyethylene and polypropylene, the inner surface layer 5 may contain a water vapor barrier layer 4 and a resin that can be adhered to a lid material (when molded into a tray). Specifically, for example, polyolefin resins other than high-density polyethylene such as cyclic olefin polymers and cyclic olefin copolymers; polyester resins; resins containing halogen atoms such as polyvinyl chloride, polyvinylidene chloride, and polychlorotrifluoroethylene. And so on.
The inner surface layer 5 may contain one type of the above resin, or may contain two or more types of the resin. By selecting the above resin, when the multilayer sheet 1 is molded into a tray, the sealing strength between the tray and the lid material can be sufficiently ensured.

Further, it is preferable that the inner surface layer 5 does not contain an inorganic filler. That is, the inner surface layer 5 is preferably a layer made of only a resin or a layer made of only a mixture of high-density polyethylene and polypropylene. When the resin layer containing the inorganic filler is used as the outermost layer of the multilayer sheet 1, the variation in the sealing strength between the tray on which the multilayer sheet 1 is molded and the lid material becomes large, and there is a possibility that sufficient sealing properties cannot be obtained. be. On the other hand, by using the inner surface layer 5 containing no inorganic filler as the outermost layer of the multilayer sheet 1, it is possible to suppress variations in the sealing strength and improve the sealing property. Specific examples of the inorganic filler include layered silicates such as talc, mica, montmorillonite, kaolin, clay, bentonite, and hectrite, silica, calcium carbonate, magnesium carbonate, calcium sulfate, and sulfate. Examples thereof include magnesium, barium sulfate, glass filler, glass fiber, glass beads, titanium oxide, aluminum oxide, iron, zinc and aluminum.

Further, since the inner surface layer 5 does not contain the inorganic filler, when the multilayer sheet 1 adheres to the die lip during the production of the multilayer sheet 1, the inorganic filler or the like adheres to the die lip, resulting in a decrease in productivity. Can be prevented.

The resin contained in the inner surface layer 5 may be the same as or different from the resin contained in the water vapor barrier layer 4 described above.

On the other hand, as the resin contained in the surface layer (hereinafter, also referred to as “outer surface layer”) 6 to be the outer surface, the same resin as the inner surface layer 5 can be used. Further, it is preferable that the outer surface layer 6 does not contain an inorganic filler, like the inner surface layer 5. When the resin layer containing the inorganic filler is used as the outermost layer of the multilayer sheet 1, the glossiness of the multilayer sheet 1 may be lost. On the other hand, by using the outer surface layer 6 containing no inorganic filler as the outermost layer of the multilayer sheet 1, the glossiness of the multilayer sheet 1 can be sufficiently ensured.

The thickness of one of the surface layers 5 and 6 is not particularly limited, but specifically, for example, it is preferably 6.25 μm or more and 375 μm or less, and 12.5 μm or more and 300 μm or less. Is more preferable. When the thickness of one of the surface layers 5 and 6 is 6.25 μm or more, the sealing strength can be stabilized and the glossiness can be sufficiently exhibited. Further, when the thickness of one of the surface layers 5 and 6 is 375 μm or less, the water vapor barrier property can be sufficiently exhibited. Further, when the thickness is 12.5 μm or more and 300 μm or less, the above effect can be obtained more remarkably.

The ratio of the total thickness of the pair of surface layers 5 and 6 is not particularly limited, but specifically, for example, it is 2.5% or more and 50% or less with respect to the total thickness of the multilayer sheet 1. It is preferable, and it is more preferable that it is 5% or more and 40% or less. When the ratio of the total thickness of the pair of surface layers 5 and 6 is 2.5% or more with respect to the total thickness of the multilayer sheet 1, the sealing strength can be stabilized and the glossiness can be sufficiently exhibited. .. Further, when the ratio is 50% or less with respect to the total thickness of the multilayer sheet 1, sufficient water vapor barrier property can be ensured. Further, when the ratio is 5% or more and 40% or less, the above effect can be obtained more remarkably.

The total thickness of the multilayer sheet 1 of the present embodiment is not particularly limited, but specifically, for example, it is preferably 500 μm or more and 1500 μm or less, and more preferably 800 μm or more and 1350 μm or less. When the total thickness of the multilayer sheet 1 is 500 μm or more, both the water vapor barrier property and the oxygen barrier property can be sufficiently exhibited. Further, when the total thickness of the multilayer sheet 1 is 1500 μm or less, the molding cycle into the container shape can be shortened. Further, when the total thickness is 800 μm or more and 1350 μm or less, the above effect can be obtained more remarkably.

As for the water vapor barrier property of the multilayer sheet 1 of the present embodiment, the water vapor permeation amount under the conditions of 40 ° C. and 90% RH measured by the cup method specified in JIS-Z 0208 is 0.15 g / m ² · day or less. Is. The water vapor permeation amount is preferably 0.13 g / m ² · day or less, and more preferably 0.10 g / m ² · day or less.

When the multilayer sheet 1 is molded into a package because the water vapor permeation amount of the multilayer sheet 1 in an atmosphere of 40 ° C. and 90% RH is 0.15 g / m ² · day or less, the content is external moisture. It becomes possible to sufficiently protect from the water vapor, and it becomes possible to store the contents sensitive to moisture for a long period of time. Further, when the content contains a liquid, it is possible to prevent evaporation of water from the content, and it is possible to maintain the liquid concentration of the content for a long period of time.

As a result, the conventional package has a low water vapor barrier property, and it is possible to extend the period of use of the product that has been discarded in a short period of time, and it is possible to reduce the amount of waste. Therefore, the total cost of the product and the amount of waste of the product and the package can be reduced.

Further, when the water vapor permeation amount is 0.13 g / m ² · day or less and 0.10 g / m ² · day or less, the above effect can be obtained more remarkably.

The water vapor permeation amount of the multilayer sheet 1 can be measured according to the method described in the JIS-Z 0208 method.

Specifically, as the oxygen barrier property of the multilayer sheet 1 of the present embodiment, it is preferable that the oxygen permeation amount is 0.35 cc / m ² · day or less in an atmosphere of 25 ° C. and 60% RH. , 0.30 cc / m ² · day or less, and particularly preferably 0.25 cc / m ² · day or less.

If the oxygen permeation amount of the multilayer sheet 1 in an atmosphere of 25 ° C. and 60% RH is 0.35 cc / m ² · day or less, when the multilayer sheet 1 is molded into a package, the contents are separated from external oxygen. It is possible to sufficiently protect the contents, prevent oxidation, deterioration, putrefaction, rust and the like of the contents, and can store the contents for a long period of time. In addition, since the contents can be stored for a long period of time without using an antioxidant, it is possible to save the trouble of enclosing the antioxidant in the package and at the same time prevent accidental ingestion of the antioxidant.

Further, when the oxygen permeation amount is 0.30 cc / m ² · day or less and 0.25 cc / m ² · day or less, the above effect can be obtained more remarkably.

The oxygen permeation amount of the multilayer sheet 1 is measured according to the method described in JIS K 7126B method using an oxygen permeation rate measuring device (for example, "OX-TRAN MODEL 2/21" manufactured by MOCON). Can be done.

Specifically, as the impact resistance of the multilayer sheet 1 of the present embodiment, for example, the tensile impact strength is preferably 110 kJ / m ² or more, more preferably 150 kJ / m ² or more, and 230 kJ. It is more preferably / m ² or more.

When the tensile impact strength of the multilayer sheet 1 is 110 kJ / m ² or more, when the multilayer sheet 1 is molded into a package, it is possible to prevent the package from being cracked due to the impact.

Further, when the tensile impact strength is 150 kJ / m ² or more and 230 kJ / m ² or more, the above effect can be obtained more remarkably.

As for the impact resistance of the multilayer sheet 1 of the present embodiment, specifically, for example, the impact strength of the DuPont type drop impact tester is preferably 1.5 J or more, preferably 2.1 J or more. Is more preferable, and 3.4 or more is further preferable.

When the impact strength of the multilayer sheet 1 in the DuPont type drop impact tester is 1.5 J or more, when the multilayer sheet 1 is molded into a package, it is possible to prevent the package from being cracked by the impact.

Further, when the impact strength of the DuPont type drop impact tester is 2.1 J or more and 3.4 J or more, the above effect can be obtained more remarkably.

As described above, in the multilayer sheet 1 of the present embodiment, the water vapor barrier layer 4 and the pair of surface layers 5 and 6 both contain high-density polyethylene. When the water vapor barrier layer 4 and the pair of surface layers 5 and 6 both contain high-density polyethylene, the effect of improving the impact resistance and the barrier property is remarkably enhanced. Further, when the pair of surface layers 5 and 6 and the water vapor barrier layer 4 are laminated adjacent to each other, the adhesion between the pair of surface layers 5 and 6 and the water vapor barrier layer 4 is improved. be able to.

In the multilayer sheet 1 of the present embodiment, when the pair of surface layers 5 and 6 and the water vapor barrier layer 4 are laminated adjacent to each other, the pair of surface layers 5 and 6 and the water vapor barrier layer 4 are laminated. Specifically, the peel strength is preferably, for example, 11N / 15 mm or more, and more preferably 15N / 15 mm or more.

When the peel strength between the pair of surface layers 5 and 6 and the water vapor barrier layer 4 in the multilayer sheet 1 is 11 N / 15 mm or more, when the multilayer sheet 1 is molded into a package, the pair is paired with the water vapor barrier layer in the package. It is possible to prevent peeling from the surface layer of the water vapor to a higher degree.

Further, when the peel strength is 15 N / 15 mm or more, the above effect can be obtained more remarkably.

<Manufacturing method of multilayer sheet>
Next, the method for manufacturing the multilayer sheet 1 described above will be described.
The method for manufacturing the multilayer sheet 1 of the present embodiment is not particularly limited, but is a coextrusion T-die such as a feed block method or a multi-manifold method in which a resin or the like as a raw material is melt-extruded by several extruders. Examples thereof include a method, an air-cooled type or a water-cooled type coextrusion inflation method and a laminating method. Among them, the method of forming a film by the coextrusion T-die method is particularly preferable because it is excellent in controlling the thickness of each layer.

Subsequent steps include a dry laminating method, an extrusion laminating method, a hot melt laminating method, a wet laminating method, a thermal (heat) laminating method, etc., in which a single-layer sheet or film forming each layer is bonded together using an appropriate adhesive. And those methods are used in combination. Further, it may be laminated by a coating method.

In addition, when adding an inorganic filler, it is better to use one that has been pre-kneaded with a kneader such as a twin-screw kneader, a kneader, or a Banbury mixer for sheet performance and contamination due to scattering of the inorganic filler during sheet film formation. It is more preferable because it can prevent.

<Packaging>
Next, a package using the above-mentioned multilayer sheet 1 will be described. FIG. 2 is a schematic cross-sectional view of a package 11 according to an embodiment to which the present invention is applied. As shown in FIG. 2, the package 11 of the present embodiment is roughly configured with a tray 12 and a lid material 13.

The package 11 of the present embodiment contains, for example, pharmaceuticals, pharmaceuticals, infusion preparations, blood products, medical devices, cosmetics, quasi-drugs, foods, beverages, industrial parts, electronic parts, electrical appliances, etc. as the contents 14. It can be used when packaging. It can also be used as a secondary packaging container for a primary package in which the contents 14 are packaged. Further, since the multilayer sheet 1 has heat resistance, it can be applied even to the contents 14 that require retort, sterility, or the like.

The tray 12 is obtained by secondary molding the multilayer sheet 1. Specifically, by denting the multilayer sheet 1, the storage space S and the edge portion 15 are formed around the storage space S.

The method for secondary forming the tray 12 from the multilayer sheet 1 is not particularly limited, but specifically, for example, vacuum forming, vacuum forming, vacuum forming, plug-assisted vacuum forming, plug-assisted vacuum forming, plug-assisted vacuum forming. Examples include vacuum forming, plug forming, press forming and the like.

The lid material 13 is adhered to the surface layer 5 on the inner surface side at the edge portion 15 of the tray 12. As a result, the storage space S is sealed. The material of the lid material 13 is not particularly limited as long as it adheres to the tray 12. Specific examples thereof include aluminum and transparent vapor-deposited films.

In the package 11 of the present embodiment, the oxygen barrier layer 2, the water vapor barrier layer 4, and the outer surface layer 6 are preferably laminated in this order from the storage space S side. As a result, the deterioration of the oxygen barrier property due to the moisture absorption of the oxygen barrier layer 2 is suppressed, and the water vapor barrier property and the oxygen barrier property of the package 11 are maximized, so that the protection period of the content 14 can be extended. It will be possible.

Further, the package 11 of the present embodiment has an inner surface layer 5, a first water vapor barrier layer 4, an oxygen barrier layer 2, a second water vapor barrier layer 4, and an outer surface layer from the storage space S side. It is preferable that 6 and 6 are laminated in this order. That is, it is preferable that the water vapor barrier layers 4 and 4 are provided on both sides of the oxygen barrier layer 2. As a result, it is possible to sufficiently exhibit the water vapor barrier property and the oxygen barrier property from the outside, and at the same time, prevent the evaporation of water from the storage space S side.

As described above, the multilayer sheet 1 of the present embodiment has the water vapor barrier layer 4, the oxygen barrier layer 2, and the pair of surface layers 5 and 6, and the surface layers are on both sides of the outermost layer. 5 and 6 are laminated, respectively, and the water vapor barrier layer 4 and the pair of surface layers 5 and 6 both contain high-density polyethylene (HDPE) and are measured by the cup method specified in JIS-Z 0208. Since the water vapor permeation amount under the conditions of 40 ° C. and 90% RH is 0.15 (g / m ² · day) or less, it is excellent in oxygen barrier property and water vapor barrier property, and also has excellent impact resistance. Sheet 1 can be provided.

Further, since the tray 12 of the present embodiment is obtained by secondary molding the multilayer sheet 1, it is excellent in oxygen barrier property and water vapor barrier property, and is also excellent in impact resistance.

Further, according to the package 11 of the present embodiment, since the tray 12 and the lid material 13 are provided, the oxygen barrier property and the water vapor barrier property are excellent, and the impact resistance is also excellent.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs and the like within a range that does not deviate from the gist of the present invention. For example, the above-mentioned multilayer sheet 1 has a crystal nucleating agent, a petroleum resin, an antistatic agent, an ultraviolet absorber, a lubricant, an antioxidant, a light stabilizer, an antiblocking agent, and a surfactant as long as the basic performance is not impaired. , Dyes, pigments, flame retardants, deodorants, plasticizers, dispersants and the like may be added to one or more layers contained in the multilayer sheet 1. By including such a layer, it is possible to improve the productivity of the multilayer sheet 1 and the package 11, prevent deterioration, and impart distinctiveness.

Further, although the configuration in which the multilayer sheet 1 described above includes the outer surface layer 6 has been described as an example, the present invention is not limited to this. For example, the configuration may not include the outer surface layer 6.

Further, the above-mentioned multilayer sheet 1 has been described as an example of a configuration in which two layers each of an adhesive layer 3 and a water vapor barrier layer 4 are provided, but the present invention is not limited thereto. For example, the adhesive layer 3 and the water vapor barrier layer 4 may be provided with only one layer each, or may be provided with two or more layers each.

Further, the above-mentioned multilayer sheet 1 has been described as an example of a configuration in which a pair of surface layers 5 and 6 and a water vapor barrier layer 4 are laminated adjacent to each other, but the present invention is not limited thereto. For example, another layer may be inserted between the pair of surface layers 5 and 6 and the water vapor barrier layer 4.

Hereinafter, the effects of the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

<Making a multi-layer sheet>
(Example 1)
A multilayer sheet having the configuration shown in FIG. 1 was produced by the following procedure.
First, as a resin for the oxygen barrier layer, an ethylene-vinyl alcohol copolymer (manufactured by Kuraray Co., Ltd., product number: F101A) was prepared.
Further, as the resin of the first and second adhesive layers, maleic anhydride-modified polyethylene (manufactured by Mitsui Chemicals, Inc., product number: NF536) was prepared.
Further, as the resin of the first and second water vapor barrier layers, high-density polyethylene (manufactured by Asahi Kasei Chemical Co., Ltd., product number: B161) was prepared.
Further, high-density polyethylene (manufactured by Asahi Kasei Chemical Co., Ltd., product number: B161) was prepared as the resin for the inner surface layer and the outer surface layer.

Next, the inner surface layer, the first water vapor barrier layer, the first adhesive layer, the oxygen barrier layer, the second adhesive layer, the second water vapor barrier layer, and the outer surface layer are formed. Multi-layer sheets were produced by co-extrusion in order. At that time, when fixing the sheet to the cooling roll, an embossed touch roll was used, and the fixing pressure was set to 0.2 MPa.

The total thickness of the multilayer sheet was 1000 μm. The ratio of the thickness of each layer to the total thickness of the multilayer sheet is 10% for the inner surface layer, 35.0% for the first water vapor barrier layer, 2.5% for the first adhesive layer, and 5 for the oxygen barrier layer. %, The second adhesive layer was 2.5%, the second water vapor barrier layer was 35.0%, and the outer surface layer was 10%.

(Example 2)
The multilayer sheet 1 was produced in the same manner as in Example 1 except that the resins of the first and second water vapor barrier layers were 92% by mass of high-density polyethylene and 8% by mass of petroleum resin.
As the petroleum resin, a hydrogenated dicyclopentadiene petroleum resin (manufactured by JXTG Energy Co., Ltd., product number: T-REZ OP501) was used.

The total thickness of the multilayer sheet was 1000 μm. The ratio of the thickness of each layer to the total thickness of the multilayer sheet is 10% for the inner surface layer, 35.0% for the first water vapor barrier layer, 2.5% for the first adhesive layer, and 5 for the oxygen barrier layer. %, The second adhesive layer was 2.5%, the second water vapor barrier layer was 35.0%, and the outer surface layer was 10%.

(Example 3)
The multilayer sheet 1 was produced in the same manner as in Example 2 except that the total thickness of the multilayer sheet was changed from 1000 μm to 1300 μm.

(Comparative Example 1)
The resin of the inner surface layer and the outer surface layer is polypropylene (manufactured by Sumitomo Chemical Co., Ltd., product number: FH1016), and the resin of the first and second water vapor barrier layers is polypropylene (manufactured by Sumitomo Chemical Co., Ltd., product number: FH1016) 72 mass. A multilayer sheet 1 was produced in the same manner as in Example 1 except that% and talc (manufactured by Nippon Tarku Co., Ltd., product number K-1) were 28% by mass.

The total thickness of the multilayer sheet was 1000 μm. The ratio of the thickness of each layer to the total thickness of the multilayer sheet is 10% for the inner surface layer, 35% for the first water vapor barrier layer, 2.5% for the first adhesive layer, and 5.0 for the oxygen barrier layer. %, The second adhesive layer was 2.5%, the second water vapor barrier layer was 35%, and the outer surface layer was 10%.

(Comparative Example 2)
The resin of the inner surface layer and the outer surface layer is a mixture of polypropylene (manufactured by Sumitomo Chemical Co., Ltd., product number: FS2011DG2) and high-density polyethylene (manufactured by Asahi Kasei Chemical Co., Ltd., product number: B161) (polypropylene 85 parts by mass, high-density polyethylene 15 parts by mass). The resin of the first and second steam barrier layers is high-density polyethylene (manufactured by Asahi Kasei Chemical Co., Ltd., product number: B161) 59% by mass, petroleum resin 8.0% by mass, talc (manufactured by Nippon Tarku Co., Ltd., product number K-). 1) The multilayer sheet 1 was produced in the same manner as in Example 1 except that the content was 33% by mass.
As the petroleum resin, a hydrogenated dicyclopentadiene petroleum resin (manufactured by JXTG Energy Co., Ltd., product number: T-REZ OP501) was used.

The total thickness of the multilayer sheet was 1000 μm. The ratio of the thickness of each layer to the total thickness of the multilayer sheet is 10% for the inner surface layer, 35% for the first water vapor barrier layer, 2.5% for the first adhesive layer, and 5.0 for the oxygen barrier layer. %, The second adhesive layer was 2.5%, the second water vapor barrier layer was 35%, and the outer surface layer was 10%.

<Evaluation of water vapor barrier property>
The water vapor barrier properties were evaluated for the multilayer sheets prepared in Examples 1 to 3 and Comparative Examples 1 and 2 and the water vapor barrier layer (single layer). The water vapor barrier property was evaluated by measuring the amount of water vapor permeation in an atmosphere of 40 ° C. and 90% RH. The results are shown in Table 1.
For the water vapor barrier layer (single layer), the amount of water vapor permeation was based on the method described in JIS-Z 0208 method.
Further, for the multilayer sheet, the water vapor permeation amount was carried out in accordance with the method described in the JIS-Z 0208 method.

<Evaluation of oxygen barrier property>
The oxygen barrier properties of the multilayer sheets prepared in Examples 1 to 3 and Comparative Examples 1 and 2 were evaluated. The oxygen barrier property was evaluated by measuring the amount of oxygen permeation in an atmosphere of 25 ° C. and 60% RH.
The oxygen permeation amount was measured by using an oxygen permeation rate measuring device (for example, "OX-TRAN MODEL 2/21" manufactured by MOCON) in accordance with the method described in JIS K 7126B method. .. The results are shown in Table 1.

<Impact resistance: Evaluation of tensile impact test>
The impact resistance of the multilayer sheets produced in Examples 1 to 3 and Comparative Examples 1 and 2 was evaluated. The impact resistance was evaluated by measuring the tensile impact strength of the multilayer sheet in accordance with the method described in the JIS K 7160A method. The results are shown in Table 1.

<Impact resistance: Evaluation of DuPont impact test>
The impact resistance was evaluated by measuring the impact strength of the multilayer sheets produced in Examples 1 to 3 and Comparative Examples 1 and 2. Specifically, a multi-layer sheet is sandwiched between the shooting type of a DuPont type drop impact tester (for example, "IM-4500" manufactured by Ueshima Seisakusho) and the cradle, and the weight is dropped from a certain height. The multi-layer sheet was impact-deformed. The impact strength was calculated from the mass and drop height of the weight when the multilayer sheet was cracked by changing the mass and drop height of the weight based on the following formula.
Impact strength (J) = Weight mass (kg) x g (gravitational acceleration) x drop height (m)
The results are shown in Table 1.

<Evaluation of peel strength>
The peel strength was evaluated for the multilayer sheets produced in Examples 1 to 3 and Comparative Examples 1 and 2. Specifically, a multilayer sheet is cut to a width of 15 mm, and the layers between the outermost layer (surface layer) and the adjacent layer (water vapor barrier layer) are pinched with tweezers to create a gripping allowance, and an autograph (for example, for example). The multilayer sheet was pulled at a speed of 200 mm / min with A & D Co., Ltd. (“RTF-1250”, etc.), and the peel strength was measured.

As shown in Table 1, according to the multilayer sheets of Examples 1 to 3, since the water vapor barrier layer contains high-density polyethylene (HDPE), the water vapor permeation amount is 0.15 g / m ² · day or less, which is extremely high. It was confirmed that it has an excellent water vapor barrier property.

Further, according to the multilayer sheets of Examples 1 to 3, it was confirmed that the oxygen barrier property was very excellent because the oxygen permeation amount was 0.35 cc / m ² · day or less.

Further, according to the multilayer sheets of Examples 1 to 3, it was confirmed that the inner surface layer and the outer surface layer contain high density polyethylene (HDPE), so that the impact resistance is also excellent.

On the other hand, according to the multilayer sheet of Comparative Example 1, since polypropylene (PP) is used as the water vapor barrier layer, the water vapor permeation amount is 0.16 g / m ² · day, and 0.15 g / m. ^A very excellent water vapor barrier property of 2.day or less could not be obtained.

Further, according to the multilayer sheet of Comparative Example 2, since the water vapor barrier layer contains high-density polyethylene (HDPE), a very excellent water vapor barrier property of 0.15 g / m ² · day or less was obtained, but water vapor. It was confirmed that the impact resistance was inferior to that of Examples 1 to 3 because the amount of water vapor used in the barrier layer was large and polypropylene (PP) was used for the inner surface layer and the outer surface layer.

The multilayer sheet of the present invention can be used as a packaging material for pharmaceuticals, pharmaceuticals, infusion preparations, blood products, medical devices, foods, beverages, industrial parts, electronic parts and the like. Further, the tray and package of the present invention may be used for packaging pharmaceuticals, cosmetics, quasi-drugs, pharmaceuticals, infusion preparations, blood products, medical devices, foods, beverages, industrial parts, electronic parts, etc. be.

1 ... Multilayer sheet, 2 ... Oxygen barrier layer, 3 ... Adhesive layer, 4 ... Water vapor barrier layer, 5 ... Surface layer (inner surface layer), 6 ... Surface layer (outer surface layer), 11 ... Package, 12 ... Tray , 13 ... lid material, 14 ... contents, 15 ... edge, S ... storage space

Claims (9)

It is a multilayer sheet having a water vapor barrier layer, an oxygen barrier layer, and a pair of surface layers, and the surface layers are laminated on both sides of the outermost layer.
The water vapor barrier layer is laminated on both sides of the surface of the oxygen barrier layer, and the pair of surface layers are laminated adjacent to the water vapor barrier layer, respectively.
The water vapor barrier layer and the pair of surface layers both contain high density polyethylene.
The content of the high-density polyethylene in the water vapor barrier layer is 92% by mass or more with respect to the total amount of the resin components contained in the water vapor barrier layer.
The pair of surface layers consists only of high density polyethylene.
The water vapor permeation amount of the multilayer sheet under the conditions of 40 ° C. and 90% RH measured by the cup method specified in JIS-Z 0208 is 0.15 (g / m ² · day) or less.
A multi-layer sheet having an impact strength of 1.5 J or more in the DuPont type drop impact tester of the multi-layer sheet. The multilayer sheet according to claim 1, wherein the water vapor barrier layer comprises only high-density polyethylene or contains a mixture of high-density polyethylene and petroleum resin. The multilayer sheet according to claim 2, wherein the petroleum resin is a polymer obtained by using dicyclopentadiene. The multilayer sheet according to any one of claims 1 to 3 , wherein the thickness of the multilayer sheet is 500 μm or more and 1500 μm or less. The multilayer sheet according to any one of claims 1 to 4 , wherein the tensile impact strength is 110 kJ / m ² or more. The multilayer sheet according to any one of claims 1 to 5 , wherein the peel strength between the surface layer and the water vapor barrier layer is 11 N / 15 mm or more. The multilayer sheet according to any one of claims 1 to 6 , wherein the oxygen permeation amount under the conditions of 25 ° C. and 60% RH is 0.35 cc / m ² · day or less. A tray formed from the multilayer sheet according to claim 1. A packaging body comprising the tray according to claim 8 and a lid material.

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