JP2019214152A - Multilayer sheet, tray and package - Google Patents

Abstract

To provide a multilayer sheet excellent in oxygen barrier property and vapor barrier property, and further excellent in impact resistance.SOLUTION: There is provided a multilayer sheet having a vapor barrier layer 4, an oxygen barrier layer 2, and a pair of surface layers 5 and 6, in which the vapor barrier layer 4 contains a specific block copolymer of styrene and olefin, and a polyolefin resin, the surface layers 5 and 6 contain a polyolefin resin and vapor permeation amount under a condition of 40°C and 90%RH is 0.15 (g/mday) or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a multilayer sheet, a tray, and a package.

  Conventionally, paper, synthetic resin sheets or films, vapor-deposited films, laminates with synthetic resin films, aluminum packaging, and the like have been used as packaging materials for pharmaceuticals, medical products, foods, beverages, and the like. When used in the above-mentioned applications, it is a property that requires protection of the contents, especially barrier properties against water vapor and oxygen, and high barrier properties are required to protect the contents for a long time. ing.

  As a material satisfying both the water vapor barrier property and the oxygen barrier property as described above, a vapor-deposited film, an aluminum package, and the like can be given. 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 their use is limited.

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

  However, polyolefin-based resins have excellent water vapor barrier properties, but are inferior in oxygen barrier properties. Therefore, various problems such as generation of oxidation, deterioration, decay or rust of the contents may occur.

  In order to solve the above problem, for example, Patent Document 1 discloses a layer containing a resin having excellent oxygen barrier properties such as an ethylene-vinyl alcohol copolymer and nylon, and a resin containing a water vapor barrier property such as a polyolefin resin. And a resin laminate having the following layers.

Japanese Patent Publication No. 06-015227

  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 uses, the actual situation is that a further water vapor barrier property is required.

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

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

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

  In order to achieve the above object, the present invention employs the following configurations.

（式中、Ｒ^１及びＲ^２は、それぞれ独立に、炭素数１〜４のアルキル基であり、Ｒ^３及びＲ^４は、それぞれ独立に、水素原子又は炭素数１〜４のアルキル基であり、ｍ及びｎは、それぞれ独立に、１以上の整数であり、＊は、結合を表す。）。
［２］前記水蒸気バリア層が、高密度ポリエチレン、または高密度ポリエチレン及び石油樹脂の混合物を含む、［１］に記載の多層シート。
［３］前記石油樹脂が、ジシクロペンタジエンを用いて得られた重合体である、［２］に記載の多層シート。
［４］前記水蒸気バリア層が、更に、無機充填剤を含む、［１］乃至［３］のいずれか１つに記載の多層シート。
［５］前記式（１）−１で表される構成単位、前記式（１）−２で表される構成単位、及び前記式（１）−３で表される構成単位を有する化合物が、スチレン−イソブチレン−スチレンブロック共重合体である、［１］乃至［４］のいずれか１つに記載の多層シート。
［６］前記ポリオレフィン系樹脂が、高密度ポリエチレンである、［１］乃至［５］のいずれか１つに記載の多層シート。
［７］少なくとも一方の表面層と前記水蒸気バリア層とが、隣接して積層される、［１］乃至［６］のいずれか１つに記載の多層シート。
［８］前記表面層が、高密度ポリエチレンのみからなる、または高密度ポリエチレン及びポリプロピレンの混合物を含む、［１］乃至［７］のいずれか１つに記載の多層シート。
［９］前記表面層が、更に、下記式（２）−１で表される構成単位、下記式（２）−２で表される構成単位、及び下記式（２）−３で表される構成単位を有する化合物を含む、［１］乃至［８］のいずれか１つに記載の多層シート：

（式中、Ｒ^５及びＲ^６は、それぞれ独立に、炭素数１〜４のアルキル基であり、Ｒ^７及びＲ^８は、それぞれ独立に、水素原子又は炭素数１〜４のアルキル基であり、ｏ及びｐは、それぞれ独立に、１以上の整数であり、＊は、結合を表す。）。
［１０］２つの前記水蒸気バリア層を有し、当該水蒸気バリア層が前記表面層とそれぞれ隣接して積層される、［１］乃至［９］のいずれか１つに記載の多層シート。
［１１］前記多層シートの厚さが、５００μｍ以上、１５００μｍ以下である、［１］乃至［１０］のいずれか１つに記載の多層シート。
［１２］前記多層シートの引張衝撃強度が、１１０ｋＪ／ｍ^２以上である、［１］乃至［１１］のいずれか１つに記載の多層シート。
［１３］前記多層シートの、デュポン式落下衝撃試験機での衝撃強度が、１．５Ｊ以上である、［１］乃至［１２］のいずれか１つに記載の多層シート。
［１４］前記表面層と前記水蒸気バリア層との剥離強度が、１１Ｎ／１５ｍｍ以上である、［７］乃至［１３］のいずれか１つに記載の多層シート。
［１５］前記多層シートの、２５℃、６０％ＲＨの条件における酸素透過量が、０．３５ｃｃ／ｍ^２・ｄａｙ以下である、［１］乃至［１４］のいずれか１つに記載の多層シート。
［１６］［１］乃至［１５］のいずれか１つに記載の多層シートを成形したトレイ。
［１７］［１６］に記載のトレイと、蓋材と、を備える包装体。 [1] A multilayer sheet having a water vapor barrier layer, an oxygen barrier layer, and a pair of surface layers, wherein the surface layers are respectively laminated on both sides of an outermost layer, wherein the water vapor barrier layer has the following formula: (1) Including a compound having a structural unit represented by -1, a structural unit represented by the following formula (1) -2, and a structural unit represented by the following formula (1) -3, and a polyolefin-based resin Each of the pair of surface layers contains a polyolefin-based resin, and the multilayer sheet has a water vapor transmission rate of 0.4% at 40 ° C. and 90% RH measured by a cup method specified in JIS-Z0208. Multilayer sheet of 15 (g / m ² · day) or less:

(Wherein, R ¹ and R ² are each independently an alkyl group having 1 to 4 carbon atoms, and R ³ and R ⁴ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. , M and n are each independently an integer of 1 or more, and * represents a bond).
[2] The multilayer sheet according to [1], wherein the water vapor barrier layer contains high-density polyethylene or a mixture of high-density polyethylene and petroleum resin.
[3] The multilayer sheet according to [2], wherein the petroleum resin is a polymer obtained using dicyclopentadiene.
[4] The multilayer sheet according to any one of [1] to [3], wherein the water vapor barrier layer further contains an inorganic filler.
[5] A compound having a structural unit represented by the formula (1) -1, a structural unit represented by the formula (1) -2, and a structural unit represented by the formula (1) -3, The multilayer sheet according to any one of [1] to [4], which is a styrene-isobutylene-styrene block copolymer.
[6] The multilayer sheet according to any one of [1] to [5], wherein the polyolefin-based resin is a high-density polyethylene.
[7] The multilayer sheet according to any one of [1] to [6], wherein at least one surface layer and the water vapor barrier layer are stacked adjacent to each other.
[8] The multilayer sheet according to any one of [1] to [7], wherein the surface layer is made of only high-density polyethylene or contains a mixture of high-density polyethylene and polypropylene.
[9] The surface layer is further represented by a structural unit represented by the following formula (2) -1, a structural unit represented by the following formula (2) -2, and a structural unit represented by the following formula (2) -3. The multilayer sheet according to any one of [1] to [8], including a compound having a structural unit:

(Wherein, R ⁵ and R ⁶ are each independently an alkyl group having 1 to 4 carbon atoms, and R ⁷ and R ⁸ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. , O and p are each independently an integer of 1 or more, and * represents a bond.)
[10] The multilayer sheet according to any one of [1] to [9], having two water vapor barrier layers, wherein the water vapor barrier layers are laminated adjacent to the surface layer, respectively.
[11] The multilayer sheet according to any one of [1] to [10], wherein the thickness of the multilayer sheet is 500 μm or more and 1500 μm or less.
[12] The multilayer sheet according to any one of [1] to [11], wherein the multilayer sheet has a tensile impact strength of 110 kJ / m ² or more.
[13] The multilayer sheet according to any one of [1] to [12], wherein the multilayer sheet has an impact strength of 1.5 J or more in a DuPont drop impact tester.
[14] The multilayer sheet according to any one of [7] to [13], wherein the peel strength between the surface layer and the water vapor barrier layer is 11 N / 15 mm or more.
[15] The multilayer according to any one of [1] to [14], wherein the multilayer sheet has an oxygen permeability under a condition of 25 ° C. and 60% RH of 0.35 cc / m ² · day or less. Sheet.
[16] A tray formed from the multilayer sheet according to any one of [1] to [15].
[17] A package comprising the tray according to [16] and a lid.

（式中、Ｒ^１及びＲ^２は、それぞれ独立に、炭素数１〜４のアルキル基であり、Ｒ^３及びＲ^４は、それぞれ独立に、水素原子又は炭素数１〜４のアルキル基であり、ｍ及びｎは、それぞれ独立に、１以上の整数であり、＊は、結合を表す。）。 The multilayer sheet of the present invention is a multilayer sheet having a water vapor barrier layer, an oxygen barrier layer, and a pair of surface layers, wherein the surface layers are respectively laminated on both sides of an outermost layer, wherein the water vapor barrier layer Is a compound having a structural unit represented by the following formula (1) -1, a structural unit represented by the following formula (1) -2, and a structural unit represented by the following formula (1) -3, and a polyolefin And the pair of surface layers each contain a polyolefin-based resin, and the water vapor permeation amount of the multilayer sheet at 40 ° C. and 90% RH measured by a cup method specified in JIS-Z0208. However, since it is 0.15 (g / m ² · day) or less, it has excellent oxygen barrier properties and water vapor barrier properties, and also has excellent impact resistance.

(Wherein, R ¹ and R ² are each independently an alkyl group having 1 to 4 carbon atoms, and R ³ and R ⁴ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. , M and n are each independently an integer of 1 or more, and * represents a bond).

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

  In addition, since the package of the present invention includes the tray and the lid material, the package has excellent oxygen barrier properties and water vapor barrier properties, and also has excellent impact resistance.

It is a sectional view showing composition of a multilayer sheet which is one embodiment to which the present 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 secondarily forming the multilayer sheet, and a package including the tray will be described in detail. In addition, in the drawings used in the following description, in order to make the features easy to understand, there are cases where the portions that become the features are enlarged for the sake of convenience, and the dimensional ratios of the respective components are not always the same as the actual ones. Absent.

<Multilayer sheet>
First, an example of a 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 schematically configured to include 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, for packaging materials such as pharmaceuticals, preparations, infusion preparations, blood preparations, medical devices, cosmetics, quasi-drugs, foods, beverages, industrial members, and electronic components. it can.

  The oxygen barrier layer 2 is a resin layer that suppresses the transmission of oxygen and water vapor, and is provided to give the multilayer sheet 1 an oxygen barrier property and a water vapor barrier property. When the multilayer sheet 1 is formed 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 an ethylene-vinyl alcohol copolymer, polyamide, polyvinyl alcohol, polyacrylonitrile, and polyvinylidene chloride. Among them, ethylene-vinyl alcohol copolymers and polyamides are particularly preferable from the viewpoint of film-forming properties with the water vapor barrier layer 4. The oxygen barrier layer 2 may include one kind of the above resin or two or more kinds of the above resins. Further, an oxygen absorbing material may be used as the oxygen barrier layer 2.

  The thickness of the oxygen barrier layer 2 is not particularly limited, but is specifically, for example, preferably 12.5 μm or more and 225 μm or less, 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, when the thickness of the oxygen barrier layer 2 is 225 μm or less, it can be easily formed at the time of forming the container, 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 more remarkably exhibited.

  The thickness ratio of the oxygen barrier layer 2 is not particularly limited, but is specifically, for example, preferably 2.5% or more and 15% or less with respect to the total thickness of the multilayer sheet 1. More preferably, it is not less than 0.5% and not more than 10%. When the ratio of the thickness of the oxygen barrier layer 2 to the total thickness of the multilayer sheet 1 is 2.5% or more, the oxygen barrier property and the water vapor barrier property can be sufficiently exhibited. Further, when the thickness ratio of the oxygen barrier layer 2 is 15% or less with respect to the total thickness of the multilayer sheet 1, the thickness ratio of the water vapor barrier layer 4 can be maintained, and the water vapor barrier property can be maintained. And sufficient oxygen barrier properties can be exhibited. Further, when the ratio is 2.5% or more and 10% or less, the above effect can be more remarkably obtained.

  The bonding 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 bonded 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. Specifically, for example, an adhesive resin such as a maleic anhydride-modified olefin or the like, a resin mixed with a resin contained in the oxygen barrier layer 2 or the water vapor barrier layer 4, and the like are included.

  The water vapor barrier layer 4 is a resin layer that suppresses the transmission of water vapor, and is provided to give the multilayer sheet 1 a water vapor barrier property. The water vapor barrier layer 4 is laminated on both sides of the surface of the oxygen barrier layer 2 with an adhesive layer 3 interposed therebetween. Thereby, when the multilayer sheet 1 of the present embodiment is formed into a package, the contents can be protected and the permeation of water vapor into the package can be suppressed. As a result, a decrease in the oxygen barrier property due to moisture absorption of the oxygen barrier layer 2 can be suppressed. Further, since the intermolecular hydrogen bonding of the resin constituting the oxygen barrier layer 2 is prevented from being cut by water vapor and the molecular gap 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.

（式中、Ｒ^１及びＲ^２は、それぞれ独立に、炭素数１〜４のアルキル基であり、Ｒ^３及びＲ^４は、それぞれ独立に、水素原子又は炭素数１〜４のアルキル基であり、ｍ及びｎは、それぞれ独立に、１以上の整数であり、＊は、結合を表す。）。 The water vapor barrier layer 4 has a structural unit represented by the following formula (1) -1, a structural unit represented by the following formula (1) -2, and a structural unit represented by the following formula (1) -3. A compound (hereinafter, this compound may be referred to as compound (1)) and a polyolefin-based resin.
When the water vapor barrier layer 4 contains the compound (1), high impact resistance can be imparted to the multilayer sheet 1.

(Wherein, R ¹ and R ² are each independently an alkyl group having 1 to 4 carbon atoms, and R ³ and R ⁴ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. , M and n are each independently an integer of 1 or more, and * represents a bond).

The alkyl group having 1 to 4 carbon atoms in R ¹ and R ² is preferably linear or branched.
Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group.
R ¹ and R ² are preferably a methyl group.

The alkyl group having 1 to ⁴ carbon atoms in R ³ and R ⁴ is the same as the alkyl group having 1 to ⁴ carbon atoms in R ¹ and R ² .
R ³ and R ⁴ are preferably a hydrogen atom.

  Preferably, m and n are each independently an integer of 2 or more.

  The weight average molecular weight Mw of the compound (1) is preferably 5,000 to 500,000, more preferably 20,000 to 300,000, and still more preferably 50,000 to 200,000. When the weight average molecular weight is within the above range, the compound (1) can impart high impact resistance to the multilayer sheet 1. In addition, the weight average molecular weight is based on a polystyrene equivalent value by a gel permeation chromatography (GPC) method.

  Compound (1) is a total of 10 to 40% by mass of the structural unit represented by formula (1) -1 and the structural unit represented by formula (1) -3 based on the total mass of compound (1). It is preferred to include. In addition, in terms of improving the air permeability resistance and durability, the structural unit represented by the formula (1) -1 and the structural unit represented by the formula (1) -3 with respect to the total mass of the compound (1). More preferably, the total content of the constituent units is 10 to 30% by mass.

  Compound (1) is the total of the number of moles of the structural unit represented by the formula (1) -2 and the structural unit represented by the formula (1) -1 and the structural unit represented by the formula (1) -3 The molar ratio is preferably 40/60 to 95/5 from the viewpoint of the rubber elasticity of the compound (1).

  In view of the rubber elasticity of the compound (1) and handling (when the degree of polymerization is less than 10,000, the compound (1) becomes liquid), the compound (1) has a structural unit represented by the formula (1) -2. The polymerization degree is preferably from 10,000 to 150,000, and the total polymerization degree of the structural unit represented by the formula (1) -1 and the structural unit represented by the formula (1) -3 is 10,000. Preferably it is ~ 30,000.

  The glass transition point of compound (1) is preferably from -100 to 20C, more preferably from -80 to 5C, and even more preferably from -70 to 0C. When the glass transition point is within the above range, the compound (1) can impart high impact resistance to the multilayer sheet 1.

  Specific examples of the compound (1) include a styrene-isobutylene-styrene block copolymer and a styrene-2-methylbutene-styrene block copolymer. Of these, a styrene-isobutylene-styrene block copolymer is preferred.

  In the multilayer sheet 1 of the present embodiment, the content of the compound (1) is preferably 2.5% by mass or more and 30% by mass or less based on the total amount of the resin components contained in the water vapor barrier layer 4. More preferably, the content is 5.0% by mass or more and 20% by mass or less. When the content of the compound (1) is equal to or more than the above lower limit with respect to the total amount of the resin components contained in the water vapor barrier layer 4, high impact resistance can be exhibited. In addition, when the content of the compound (1) is equal to or less than the upper limit, the water vapor barrier property can be maintained.

  The water vapor barrier layer 4 contains a polyolefin resin. When the water vapor barrier layer 4 contains a polyolefin-based resin, impact resistance and barrier properties can be improved. Specific examples of the polyolefin-based resin include polyethylene and polypropylene. Of these, polyethylene is preferred, and high density polyethylene is more preferred from the viewpoints of impact resistance and barrier properties.

  Specifically, the content of the polyolefin-based resin in the steam barrier layer 4 is, for example, preferably 10 to 97.5% by mass, and more preferably 20 to 95% by mass with respect to the mass of the entire steam barrier layer 4. % Is more preferable. When the content of the polyolefin resin in the water vapor barrier layer 4 is within the above range with respect to the mass of the water vapor barrier layer 4, the effect of using the polyolefin resin is more remarkably obtained.

  In the water vapor barrier layer 4, the content ratio of the compound (1) (parts by mass) to the content of the polyolefin resin (parts by mass) is preferably 2.5: 97.5 to 50:50, More preferably, the ratio is 5.0: 95 to 45:55. When the content ratio is in such a range, the effect of using the compound (1) and the polyolefin-based resin together can be more remarkably obtained.

  As described above, the water vapor barrier layer 4 may include high-density polyethylene as the polyolefin-based resin, and in that case, may include a mixture of high-density polyethylene and petroleum resin. By including high-density polyethylene or petroleum resin in the resin component contained in the water vapor barrier layer 4, an extremely high water vapor barrier property can be imparted to the multilayer sheet 1.

  When the water vapor barrier layer 4 contains high-density polyethylene and does not contain petroleum resin, it may contain only high-density polyethylene other than the compound (1), or may contain either high-density polyethylene or petroleum resin. May also contain other components that do not apply.

  When the water vapor barrier layer 4 contains a mixture of high-density polyethylene and petroleum resin, it may contain only the mixture other than the compound (1), or corresponds to the mixture (that is, high-density polyethylene and petroleum resin). It may contain other components that do not.

  In this case, the content of the mixture in the water vapor barrier layer 4 is specifically, for example, preferably 30 to 97.5% by mass, and more preferably 35 to 97.5% by mass based on the total mass of the water vapor barrier layer 4. More preferably, it is 95% by mass. When the content of the mixture in the water vapor barrier layer 4 is within the above range with respect to the mass of the entire water vapor barrier layer 4, the effect of using the mixture is more remarkably obtained.

  When the water vapor barrier layer 4 contains a mixture of high-density polyethylene and petroleum resin, in this mixture, the content ratio of high-density polyethylene (parts by mass): content of petroleum resin (parts by mass) is 97.5. : 2.5 to 60:40, more preferably 95: 5 to 65:35. When the content ratio is in such a range, the effect of using the high-density polyethylene and the petroleum resin together is more remarkably obtained.

Note that the high-density polyethylene (HDPE) herein shall density refers to the polyethylene resin in the range of ^{0.941g / cm 3 ~0.970g / cm 3} . Among these, from the viewpoint of water vapor barrier property is preferably 0.950 g / cm ³ or more ones, 0.955 g / cm ³ or more is more preferable.

Here, the petroleum resin, petroleum naphtha and pyrolysis of ethylene, of the remaining fraction was collected fractions such as propylene and butadiene, refers primarily C ₅ based or resin obtained from C ₉ based fraction.

As the petroleum resin, an aliphatic petroleum resin, an aromatic hydrocarbon resin-based petroleum resin, an alicyclic saturated hydrocarbon resin-based petroleum resin, a copolymer petroleum resin, or the like can be used.
Above all, the petroleum resin is preferably an aliphatic hydrocarbon resin from the viewpoint of transparency and odor, more preferably a polymer obtained using dicyclopentadiene, and further preferably dicyclopentadiene. Is a hydrogenated dicyclopentadiene-based petroleum resin obtained by subjecting a compound to thermal polymerization and then subjecting it to a hydrogenation reaction. The content ratio of the structural unit derived from dicyclopentadiene to all the structural units in the petroleum resin is preferably 30% or more.

  The softening point of the petroleum resin (ring and ball method, conforming to JIS K2548) is preferably about 70 to 150 ° C, more preferably 90 to 140 ° C. When the softening point is 70 ° C. or higher, the balance between the adhesive performance and heat resistance of the composition to polyolefin is improved. When the softening point is 150 ° C. or lower, the production of the resin is facilitated and the production cost is advantageous, which is preferable.

  The number average molecular weight of the petroleum resin is preferably from 300 to 2,000, more preferably from 350 to 1,000. When the number average molecular weight is at least the above range, the adhesive performance such as the cohesive force of the resin composition will be good, and the water vapor barrier property will also be improved. When the number average molecular weight is equal to or less than the above range, the compatibility with the rubber-based polymer or the synthetic resin-based polymer of the base polymer is improved, and the production of the resin is facilitated, which is advantageous in terms of production cost. Is preferred. In addition, the number average molecular weight is based on a polystyrene conversion value by a gel permeation chromatography (GPC) method.

  Specifically, the content of the petroleum resin in the water vapor barrier layer 4 is, for example, preferably 40% by mass or less, and more preferably 5% by mass or more and 35% by mass with respect to the total mass of the water vapor barrier layer 4. It is more preferred that: When the content of the petroleum resin in the water vapor barrier layer 4 is 40% by mass or less based on the total weight of the water vapor barrier layer 4, the water vapor barrier property of the water vapor barrier layer 4 is improved, and the multilayer sheet 1 as a whole is obtained. Water vapor barrier properties 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 total mass of the water vapor barrier layer 4, the above-mentioned effect is more remarkably obtained.

  The water vapor barrier layer 4 contains the compound (1) in the resin component from the viewpoints of moldability into the multilayer sheet 1, moldability into the package, sealability with the lid material, adhesiveness with the adjacent layer, and cost. And one or more other resins that do not correspond to any of the above, the high-density polyethylene, and the petroleum resin. For example, the water vapor barrier layer 4 may include a polyolefin-based resin such as polypropylene, a cyclic olefin polymer, and a cyclic olefin copolymer; and a resin containing a halogen atom such as polyvinyl chloride, polyvinylidene chloride, and polychlorotrifluoroethylene. .

  The water vapor barrier layer 4 may further contain an inorganic filler. As the inorganic filler, specifically, for example, layered silicates such as talc, mica, montmorillonite, kaolin, clay, bentonite, hectorite, silica, calcium carbonate, magnesium carbonate, calcium sulfate, magnesium sulfate, barium sulfate , Glass filler, glass fiber, glass beads, titanium oxide, aluminum oxide, iron, zinc, aluminum and the like. Of these, talc and mica are preferred. The water vapor barrier layer 4 may include one kind of the inorganic filler or two or more kinds.

  When the water vapor barrier layer 4 contains an inorganic filler, extremely high water vapor barrier properties can be imparted to the multilayer sheet 1. The multilayer sheet 1 can also be colored by containing, for example, a pigment such as titanium oxide as an inorganic filler. On the other hand, when the water vapor barrier layer 4 contains an inorganic filler, impact resistance may be reduced. Therefore, from the viewpoint of suppressing a decrease in impact resistance, the content of the inorganic filler is preferably 40% by mass or less, and more preferably 35% by mass or less, based on the total mass of the water vapor barrier layer 4. More preferred.

  The thickness of one layer of the water vapor barrier layer 4 is not particularly limited, but specifically, for example, 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. 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-mentioned effect is more remarkably obtained.

  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, may be 45% or more and 87.5% or less with respect to the total thickness of the multilayer sheet 1. More preferably, it is 50% or more and 85% or less. When the ratio of the total thickness of the two layers of the water vapor barrier layer 4 to the total thickness of the multilayer sheet 1 is 45% or more, the sheet as a whole can sufficiently exhibit water vapor barrier properties. Further, when the ratio of the total thickness of the two layers of the water vapor barrier layer 4 to the total thickness of the multilayer sheet 1 is 87.5% or less, a sufficient oxygen barrier property is secured in addition to the water vapor barrier property. be able to. Further, when the above ratio is 50% or more and 85% or less, the above-mentioned effect is more remarkably obtained.

Specifically, the amount of water vapor permeated by the water vapor barrier layer 4 is, for example, preferably 0.6 g / m ² · day or less, and 0.55 g / m ² · day or less in an atmosphere of 40 ° C. and 90% RH. Is more preferable, and 0.5 g / m ² · day or less is particularly preferable. When the water vapor transmission rate 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 transmission rate to the oxygen barrier layer 2 decreases, and the oxygen barrier A decrease in the oxygen barrier property due to 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 transmission rate is 0.55 g / m ² · day or less and 0.5 g / m ² · day or less, the above-mentioned effect is more remarkably obtained.

  The measurement of the amount of water vapor permeated by the water vapor barrier layer 4 can be performed according to the method described in JIS-Z0208.

The pair of surface layers 5 and 6 are respectively provided as outermost layers on both sides of the multilayer sheet 1 in order to provide the multilayer sheet 1 with sealing properties, glossiness, and impact resistance. Here, the pair of surface layers 5 and 6 are laminated so as to be adjacent to the water vapor barrier layer 4 respectively.
In the multilayer sheet 1, if at least one of the pair of surface layers 5 and 6 is laminated adjacent to the water vapor barrier layer 4, the effect of providing the surface layer is higher, and as shown in FIG. If the layers 5 and 6 are both laminated adjacent to the water vapor barrier layer 4, the effect of providing the surface layer is further enhanced.

  Each of the pair of surface layers 5 and 6 contains a polyolefin-based resin. When both of the pair of surface layers 5 and 6 contain a polyolefin-based resin, impact resistance and barrier properties can be improved. Specific examples of the polyolefin-based resin include polyethylene and polypropylene. Of these, polyethylene is preferred, and high density polyethylene is more preferred from the viewpoints of impact resistance and barrier properties.

  When the multilayer sheet 1 is formed 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. At the same time as suppressing the variation, the sealing performance can be improved. On the other hand, the outer surface layer 6 (outer surface) imparts gloss and impact resistance, so that 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 5 serving as the inner surface (hereinafter, also referred to as “inner surface layer”) 5 may be composed of only high-density polyethylene, or may include a mixture of high-density polyethylene and polypropylene. By including the high-density polyethylene as an essential component in the resin contained in the inner surface layer 5, when the multilayer sheet 1 is formed into a tray, the sealing strength between the tray and the lid member and the adjoining portion are determined. Adhesion with the water vapor barrier layer can be sufficiently ensured.

When the inner surface layer 5 contains high-density polyethylene and does not contain polypropylene, it may contain only high-density polyethylene, or may contain other components that do not correspond to any of high-density polyethylene and polypropylene. It may be.
In this case, the content of the high-density polyethylene in the inner surface layer 5 is specifically, for example, preferably 50 to 100% by mass, and more preferably 70 to 100% by mass with respect to the mass of the entire inner surface layer 5. More preferably, it is mass%. When the content of the high-density polyethylene in the inner surface layer 5 is within the above range with respect to the mass of the entire inner surface layer 5, the effect of using the high-density polyethylene is more remarkably obtained.

When the inner surface layer 5 includes a mixture of high-density polyethylene and polypropylene, the inner surface layer 5 may include only the mixture, or may include other components that do not correspond to the mixture (that is, high-density polyethylene and polypropylene). Good.
In this case, the content of the mixture in the inner surface layer 5 is specifically, for example, preferably 50 to 100% by mass, and more preferably 70 to 100% by mass based on the total mass of the inner surface layer 5. % Is more preferable. When the content of the mixture in the inner surface layer 5 is within the above range with respect to the mass of the entire inner surface layer 5, the effect of using the mixture is more remarkably obtained.

  When the inner surface layer 5 contains a mixture of high-density polyethylene and polypropylene, in this mixture, the content ratio of high-density polyethylene (parts by mass): polypropylene content (parts by mass) is 10:90 to 95. : 5, more preferably 15:85 to 90:10. When the content ratio is in such a range, the effect of using high-density polyethylene and polypropylene together can be more remarkably obtained.

（式中、Ｒ^５及びＲ^６は、それぞれ独立に、炭素数１〜４のアルキル基であり、Ｒ^７及びＲ^８は、それぞれ独立に、水素原子又は炭素数１〜４のアルキル基であり、ｏ及びｐは、それぞれ独立に、１以上の整数であり、＊は、結合を表す。）。 The inner surface layer 5 further includes a structural unit represented by the following formula (2) -1, a structural unit represented by the following formula (2) -2, and a structural unit represented by the following formula (2) -3 (Hereinafter, this compound may be referred to as compound (2)).
When the inner surface layer 5 contains the compound (2), high impact resistance can be imparted to the multilayer sheet 1.

(Wherein, R ⁵ and R ⁶ are each independently an alkyl group having 1 to 4 carbon atoms, and R ⁷ and R ⁸ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. , O and p are each independently an integer of 1 or more, and * represents a bond.)

^{R 5} and ^{R 6} of formula (2) in -2, respectively, is the same as ^{R 1} and ^{R 2} of formula (1) -2.
R ⁷ and R ⁸ in the formula (2) -2 are the same as R ³ and R ⁴ in the formula (1) -2, respectively.
O in the formulas (2) -1 and (2) -3 is the same as m in the formulas (1) -1 and (1) -3.
P in the formula (2) -2 is the same as n in the formula (1) -2.

  The compound (2) contained in the inner surface layer 5 may be the same as or different from the compound (1) contained in the water vapor barrier layer 4.

  The inner surface layer 5 may contain, in addition to the polyolefin-based resin and the compound (2), a resin that can be bonded to the water vapor barrier layer 4 and 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 the like.

  The inner surface layer 5 may include one type of the above resin, or may include two or more types of the above resin. By selecting the above resin, when forming the multilayer sheet 1 into a tray, it is possible to sufficiently secure the sealing strength between the tray and the lid member.

  Further, it is preferable that the inner surface layer 5 does not contain an inorganic filler. When the resin layer containing the inorganic filler is used as the outermost layer of the multilayer sheet 1, the sealing strength between the tray on which the multilayer sheet 1 is formed and the lid member varies greatly, and there is a possibility that sufficient sealing properties may not be obtained. is there. On the other hand, by using the inner surface layer 5 containing no inorganic filler as the outermost layer of the multilayer sheet 1, variations in sealing strength can be suppressed, and sealing properties can be improved. In addition, as the inorganic filler, specifically, for example, layered silicates such as talc, mica, montmorillonite, kaolin, clay, bentonite, hectorite, silica, calcium carbonate, magnesium carbonate, calcium sulfate, magnesium sulfate, Examples include barium sulfate, glass filler, glass fiber, glass beads, titanium oxide, aluminum oxide, iron, zinc, and aluminum.

  Furthermore, since the inner surface layer 5 does not contain an inorganic filler, when the multilayer sheet 1 is bonded to the die lip during the production of the multilayer sheet 1, the productivity is reduced due to the inorganic filler or the like adhering to the die lip. 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 above-described water vapor barrier layer 4.

  On the other hand, the same resin as the inner surface layer 5 can be used as the resin contained in the surface layer 6 (hereinafter, also referred to as “outer surface layer”) 6 serving as the outer surface. Further, it is preferable that the outer surface layer 6 does not contain an inorganic filler similarly to 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 gloss of the multilayer sheet 1 may be lost. On the other hand, by setting the outer surface layer 6 containing no inorganic filler as the outermost layer of the multilayer sheet 1, the gloss 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 is specifically, for example, preferably from 6.25 μm to 375 μm, and more preferably from 12.5 μm to 330 μm. Is more preferable. When one of the surface layers 5 and 6 has a thickness of 6.25 μm or more, the sealing strength can be stabilized and the gloss can be sufficiently exhibited. When one of the surface layers 5 and 6 has a thickness of 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-described effect is more remarkably obtained.

  The ratio of the thickness of the pair of surface layers 5 and 6 is not particularly limited. Specifically, for example, the ratio is 2.5% or more and 50% or less with respect to the total thickness of the multilayer sheet 1. Is preferably 5% or more and 45% or less. If the ratio of the thickness of the pair of surface layers 5 and 6 to the total thickness of the multilayer sheet 1 is 2.5% or more, the sealing strength can be sufficiently stabilized and the gloss can be sufficiently exhibited. . Further, if the ratio is 50% or less with respect to the total thickness of the multilayer sheet 1, a sufficient water vapor barrier property can be secured. Further, when the ratio is 5% or more and 45% or less, the above-described effect is more remarkably obtained.

  The total thickness of the multilayer sheet 1 of the present embodiment is not particularly limited, but specifically, for example, 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 cycle for molding into a container can be shortened. Further, when the total thickness is 800 μm or more and 1350 μm or less, the above-mentioned effect is more remarkably obtained.

As the water vapor barrier property of the multilayer sheet 1 of the present embodiment, the water vapor transmission rate 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. in it is preferably not more than 0.13g ^/ m 2 · day, and more preferably less 0.10g ^/ m 2 · day.

When the multilayer sheet 1 has a water vapor permeation amount of 0.15 g / m ² · day or less under an atmosphere of 40 ° C. and 90% RH, when the multilayer sheet 1 is formed into a package, the content is reduced to an external moisture. Thus, the contents that are vulnerable to moisture can be stored 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, in the conventional package, the water vapor barrier property is low, and it is possible to extend the use period of the product that has been discarded in a short period of time, and it is possible to reduce the amount of waste. Therefore, it is possible to reduce the total cost of the product and the amount of disposal of the product and the package.

Furthermore, the water vapor permeation amount, 0.13g ^/ m 2 · day or less, not more than 0.10g ^/ m 2 · day, the effect is obtained more remarkably.

As the oxygen barrier property of the multilayer sheet 1 of the present embodiment, specifically, for example, it is preferable that the oxygen permeation amount is 0.35 cc / m ² · day or less under 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 multilayer sheet 1 has an oxygen permeation amount of 0.35 cc / m ² · day or less under an atmosphere of 25 ° C. and 60% RH, when the multilayer sheet 1 is formed into a package, the contents are removed from external oxygen. It is possible to sufficiently protect the contents, prevent the contents from oxidizing, deteriorating, decaying, rusting, etc., and preserve the contents for a long time. Further, 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 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 more remarkably obtained.

  The measurement of the amount of oxygen permeation of the multilayer sheet 1 is based on a method described in JIS K 7126B using an oxygen permeability measuring device (for example, “OX-TRAN MODEL 2/21” manufactured by MOCON). You can do it.

The impact resistance of the multilayer sheet 1 of the present embodiment, specifically, for example, tensile impact strength, is preferably 110 kJ / ^{m 2} or more, more preferably 150 kJ / ^{m 2} or more, 230KJ / M ² or more.

If the multilayer sheet 1 has a tensile impact strength of 110 kJ / m ² or more, when the multilayer sheet 1 is formed into a package, cracking of the package due to impact can be prevented.

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

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

  If the multilayer sheet 1 has an impact strength of 1.5 J or more in a DuPont drop impact tester, when the multilayer sheet 1 is formed into a package, the package can be prevented from cracking due to impact.

  Further, when the impact strength with the above-mentioned DuPont type drop impact tester is 2.1 J or more and 3.4 J or more, the above-mentioned effect is more remarkably obtained.

  In the multilayer sheet 1 of the present embodiment, the water vapor barrier layer 4 and the pair of surface layers 5 and 6 may each include high-density polyethylene. When both the water vapor barrier layer 4 and the pair of surface layers 5 and 6 contain high-density polyethylene, the effect of improving impact resistance and barrier properties is significantly increased. 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 adjacently, the pair of surface layers 5 and 6 and the water vapor barrier layer 4 Specifically, the peel strength is, for example, preferably 11 N / 15 mm or more, and more preferably 15 N / 15 mm or more.

  If 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 formed into a package, the multilayer sheet 1 and the water vapor barrier layer in the package are paired. Can be prevented to a higher degree from the surface layer.

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

  In the multilayer sheet 1, the peel strength between one of the pair of surface layers 5 and 6 and the water vapor barrier layer 4 may not satisfy the above-described condition. It is preferable that the peel strength between the layer and the water vapor barrier layer 4 satisfies the above conditions.

<Production method of multilayer sheet>
Next, a method for manufacturing the above-described multilayer sheet 1 will be described.
The method for producing the multilayer sheet 1 of the present embodiment is not particularly limited, but a co-extrusion T-die such as a feed block method or a multi-manifold method for melting and extruding a resin or the like as a raw material using several extruders. Method, air-cooled or water-cooled co-extrusion inflation method and laminating method. Among them, a method of forming a film by a co-extrusion T-die method is particularly preferable because it is excellent in controlling the thickness of each layer.

  As a subsequent step, a dry lamination method, an extrusion lamination method, a hot melt lamination method, a wet lamination method, a thermal (thermal) lamination method, etc., in which a single-layer sheet or film forming each layer is bonded using an appropriate adhesive, And a combination of these methods. Moreover, you may laminate | stack by the method by a coating.

  In addition, when adding the inorganic filler, it is better to use a material kneaded in advance with a kneader such as a twin-screw kneader, a kneader, or a Banbury mixer to improve the sheet performance and contamination due to scattering of the inorganic filler during sheet formation. This is more preferable because it can be prevented.

<Package>
Next, a package using the above-described 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 schematically configured to include a tray 12 and a lid 13.

  The package 11 of the present embodiment includes, as the contents 14, for example, medicines, preparations, infusion preparations, blood preparations, medical equipment, cosmetics, quasi-drugs, foods, beverages, industrial parts, electronic parts, electric appliances, and the like. It can be used for packaging. Further, it can also be used as a secondary packaging container of a primary package in which the above-mentioned contents 14 are packaged. Furthermore, since the multilayer sheet 1 has heat resistance, it can be applied to the contents 14 that need to be retorted or sterilized.

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

  The method of secondary forming the tray 12 from the multilayer sheet 1 is not particularly limited, but specific examples thereof include, for example, vacuum forming, pressure forming, pressure forming, plug assist pressure forming, plug assist pressure forming, plug assist pressure forming. Vacuum forming, plug forming, press forming, and the like are included.

  The lid member 13 is adhered to the surface layer 5 on the inner surface side at the edge portion 15 of the tray 12. Thereby, the storage space S is sealed. The material of the lid member 13 is not particularly limited as long as it can adhere to the tray 12. Specifically, for example, aluminum, a transparent vapor-deposited film and the like can be mentioned.

  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 stacked in this order from the storage space S side. This suppresses a decrease in the oxygen barrier property due to moisture absorption of the oxygen barrier layer 2 and maximizes the water vapor barrier property and the oxygen barrier property of the package 11, thereby extending the protection period of the contents 14. It becomes possible.

  Further, the package 11 of the present embodiment includes, from the storage space S side, the inner surface layer 5, the first water vapor barrier layer 4, the oxygen barrier layer 2, the second water vapor barrier layer 4, and the outer surface layer. 6 are preferably stacked 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. Thereby, the water vapor barrier property and the oxygen barrier property from the outside are sufficiently exhibited, and the water evaporation from the storage space S side can be prevented.

As described above, the multilayer sheet 1 of the present embodiment has a water vapor barrier layer, an oxygen barrier layer, and a pair of surface layers, and the surface sheet is laminated on both sides of the outermost layer. Wherein the water vapor barrier layer is represented by a structural unit represented by the following formula (1) -1, a structural unit represented by the following formula (1) -2, and a structural unit represented by the following formula (1) -3 A compound having a structural unit, wherein the pair of surface layers each include a polyolefin-based resin, and the multilayer sheet is measured at 40 ° C. and 90% RH, as measured by a cup method specified in JIS-Z0208. Since the water vapor transmission rate is 0.15 (g / m ² · day) or less, it is possible to provide the multilayer sheet 1 having excellent oxygen barrier properties and water vapor barrier properties, and also excellent impact resistance.

  Further, since the tray 12 of the present embodiment is obtained by subjecting the multilayer sheet 1 to secondary molding, the tray 12 has excellent oxygen barrier properties and water vapor barrier properties, and also has excellent impact resistance.

  In addition, according to the package 11 of the present embodiment, since the package 12 includes the tray 12 and the lid member 13, the package 11 has excellent oxygen barrier properties and water vapor barrier properties, and also has excellent impact resistance.

  As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to the embodiments, and includes a design and the like within a range not departing from the gist of the present invention. For example, the above-described multilayer sheet 1 has a 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. Additives such as dyes, pigments, flame retardants, deodorants, plasticizers, and dispersants may be added to one or more layers included 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, the above-described multilayer sheet 1 has been described as an example of the configuration including the outer surface layer 6, but is not limited thereto. For example, a configuration without the outer surface layer 6 may be employed.

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

  Further, in the above-described multilayer sheet 1, a configuration in which the pair of surface layers 5 and 6 and the water vapor barrier layer 4 are laminated adjacent to each other has been described as an example, 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.

<Preparation of multilayer sheet>
(Example 1)
A multilayer sheet having the configuration shown in FIG. 1 was produced by the following procedure.
First, an ethylene-vinyl alcohol copolymer (manufactured by Kuraray, product number: F101A) was prepared as a resin contained in the oxygen barrier layer.
In addition, maleic anhydride-modified polyethylene (manufactured by Mitsui Chemicals, Inc., product number: NF536) was prepared as a resin contained in the first and second adhesive layers.
Further, as the resin contained in the first and second water vapor barrier layers, styrene-isobutylene-styrene block copolymer (manufactured by Kaneka Corporation, product number: 102T-UC) and high-density polyethylene (manufactured by Asahi Kasei Chemical Company, product number: B161) ) Was prepared.
In the first and second water vapor barrier layers, the mixing ratio was adjusted so that the styrene-isobutylene-styrene block copolymer was 15% by mass and the high-density polyethylene was 85% by mass.
Also, high-density polyethylene (manufactured by Asahi Kasei Chemical Corporation, product number: B161) was prepared as a 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 Co-extrusion molding was performed in order to produce a multilayer sheet. When fixing the sheet to the cooling roll, an embossing 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)
A hydrogenated dicyclopentadiene-based petroleum resin (manufactured by JXTG Energy, product number: T-REZ OP501) was prepared as a resin contained in the first and second water vapor barrier layers.
In the first and second water vapor barrier layers, except that the mixing ratio was adjusted so that the styrene-isobutylene-styrene block copolymer was 15% by mass, the high-density polyethylene was 75% by mass, and the petroleum resin was 10% by mass. A multilayer sheet 1 was produced in the same manner as in Example 1.

Example 3
Talc (manufactured by Nippon Talc, product number K-1) was prepared as an inorganic filler contained in the first and second water vapor barrier layers.
In the first and second water vapor barrier layers, styrene-isobutylene-styrene block copolymer was mixed at 15% by mass, high-density polyethylene at 45% by mass, petroleum resin at 10% by mass, and talc at 30% by mass. A multilayer sheet 1 was produced in the same manner as in Example 2 except that the ratio was adjusted.

(Example 4)
A styrene-isobutylene-styrene block copolymer (manufactured by Kaneka Corporation, product number: 102T-UC) was prepared as a resin contained in the inner surface layer and the outer surface layer.
In the inner surface layer and the outer surface layer, a multilayer was prepared in the same manner as in Example 3 except that the mixing ratio was adjusted so that the styrene-isobutylene-styrene block copolymer was 10% by mass and the high-density polyethylene was 90% by mass. Sheet 1 was produced.

(Comparative Example 1)
Polypropylene (manufactured by Sumitomo Chemical Co., Ltd., product number: FH1016) was prepared as a resin contained in the first and second water vapor barrier layers, and the inner and outer surface layers.
Talc (manufactured by Nippon Talc, product number K-1) was prepared as an inorganic filler contained in the first and second water vapor barrier layers.
In the same manner as in Example 1 except that the resin contained in the first and second water vapor barrier layers was 75% by mass of polypropylene and 25% by mass of talc, and the resin contained in the inner surface layer and the outer surface layer was polypropylene. Thus, a multilayer sheet 1 was prepared.

(Reference Example 2)
Except for removing the styrene-isobutylene-styrene block copolymer from the resins contained in the first and second water vapor barrier layers, and adjusting the mixing ratio so that high-density polyethylene was 90% by mass and petroleum resin was 10% by mass. In the same manner as in Example 2, a multilayer sheet 1 was prepared.

(Comparative Example 2)
Excluding the styrene-isobutylene-styrene block copolymer from the resin contained in the first and second water vapor barrier layers, the high-density polyethylene was 60% by mass, the petroleum resin was 10% by mass, and the talc was 30% by mass. A multilayer sheet 1 was prepared in the same manner as in Example 3 except that the mixing ratio was adjusted.

<Evaluation of water vapor barrier properties>
The multilayer sheets and the water vapor barrier layer (single layer) produced in Examples 1 to 4, Comparative Examples 1 and 2, and Reference Example 1 were evaluated for water vapor barrier properties. The evaluation of the water vapor barrier property was performed by measuring the amount of water vapor transmission under an atmosphere of 40 ° C. and 90% RH. The results are shown in Table 1.
In addition, about the water vapor | steam barrier layer (single layer), the water vapor permeation amount was performed based on the method of JIS-Z0208 method.
The water vapor transmission rate of the multilayer sheet was measured according to the method described in JIS-Z0208.

<Evaluation of oxygen barrier properties>
The oxygen barrier properties of the multilayer sheets produced in Examples 1 to 4, Comparative Examples 1 and 2, and Reference Example 1 were evaluated. The oxygen barrier property was evaluated by measuring the amount of oxygen permeated in an atmosphere of 25 ° C. and 60% RH.
In addition, the measurement of the oxygen transmission rate was performed based on the method of JISK7126B method using the oxygen transmission rate measuring apparatus (for example, "OX-TRAN MODEL 2/21" by MOCON). . The results are shown in Table 1.

<Impact resistance: Evaluation of tensile impact test>
The multilayer sheets produced in Examples 1 to 4, Comparative Examples 1 and 2, and Reference Example 1 were evaluated for impact resistance. The evaluation of impact resistance was performed by measuring the tensile impact strength of the multilayer sheet according to the method described in JIS K 7160A. The results are shown in Table 1.

<Impact resistance: Evaluation of DuPont impact test>
Impact resistance was evaluated by measuring the impact strength of the multilayer sheets produced in Examples 1 to 4, Comparative Examples 1 and 2, and Reference Example 1. Specifically, a multilayer sheet is sandwiched between a shooting die of a Dupont-type drop impact tester (for example, “IM-4500” manufactured by Ueshima Seisakusho, etc.) and a pedestal, and a weight is dropped from a certain height. The multilayer sheet was subjected to impact deformation. The impact strength was calculated based on the following equation from the weight and the drop height when the multilayer sheet was cracked while changing the weight and the drop height of the weight. The results are shown in Table 1.
[Equation 1]
Impact strength (J) = mass of weight (kg) x g (gravitational acceleration) x drop height (m)

<Evaluation of peel strength>
The multilayer sheets produced in Examples 1 to 4, Comparative Examples 1 and 2, and Reference Example 1 were evaluated for peel strength. Specifically, a multilayer sheet is cut to a width of 15 mm, and the outermost layer (surface layer) and the adjacent layer (water vapor barrier layer) are pinched with tweezers to produce a gripping allowance, and an autograph (for example, The multilayer sheet was pulled at a speed of 200 mm / min using A & D, Inc., “RTF-1250” or the like, and the peel strength was measured. The results are shown in Table 1.

As shown in Table 1, according to the multilayer sheets of Examples 1 to 4, since the water vapor barrier layer and the inner surface layer and the outer surface layer contain high-density polyethylene (HDPE), the water vapor transmission amount is 0.1%. It was 15 g / m ² · day or less, and it was confirmed that it had a very excellent water vapor barrier property.
On the other hand, according to the multilayer sheet of Comparative Example 1, since the water vapor barrier layer contains polypropylene (PP), the water vapor transmission rate is 0.16 g / m ² · day, and 0.15 g / m ² -An extremely excellent water vapor barrier property of not more than day was not obtained.

According to the multilayer sheets of Examples 1 to 4, since the oxygen permeation amount was 0.35 cc / m ² · day or less, it was confirmed that the multilayer sheets had extremely excellent oxygen barrier properties.

According to the multilayer sheets of Examples 1 to 4, since the water vapor barrier layer contains a styrene-isobutylene-styrene block copolymer, the tensile impact strength is 110 kJ / m ² or more, and a DuPont drop impact tester is used. Was 1.5 J or more, and it was confirmed that the sample had extremely excellent impact resistance.

  According to the multilayer sheet of Example 2, since the water vapor barrier layer contained the styrene-isobutylene-styrene block copolymer, it was confirmed that the multilayer sheet of Reference Example 1 was superior in impact resistance.

  According to the multilayer sheet of Example 3, since the water vapor barrier layer contains the styrene-isobutylene-styrene block copolymer, it was confirmed that the multilayer sheet of Comparative Example 2 was superior in impact resistance.

  According to the multilayer sheet of Example 4, since the inner surface layer and the outer surface layer further contain a styrene-isobutylene-styrene block copolymer, the multilayer sheet has better impact resistance than the multilayer sheet of Example 3. It was confirmed.

  According to the multilayer sheets of Examples 1 and 2, since the water vapor barrier layer did not contain talc, it was confirmed that the multilayer sheets of Examples 3 and 4 had better impact resistance.

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

  DESCRIPTION OF SYMBOLS 1 ... Multilayer sheet, 2 ... Oxygen barrier layer, 3 ... Adhesion layer, 4 ... Steam 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 (17)

A water vapor barrier layer, an oxygen barrier layer, and a pair of surface layers, a multilayer sheet having the surface layers laminated on both sides of the outermost layer,
The water vapor barrier layer has a structural unit represented by the following formula (1) -1, a structural unit represented by the following formula (1) -2, and a structural unit represented by the following formula (1) -3. Including a compound, and a polyolefin-based resin,
The pair of surface layers each include a polyolefin-based resin,
A multilayer sheet having a water vapor transmission rate of 0.15 (g / m ² · day) or less under the conditions of 40 ° C. and 90% RH, measured by the cup method specified in JIS-Z 0208, for the multilayer sheet:

(Wherein, R ¹ and R ² are each independently an alkyl group having 1 to 4 carbon atoms, and R ³ and R ⁴ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. , M and n are each independently an integer of 1 or more, and * represents a bond).   The multilayer sheet according to claim 1, wherein the water vapor barrier layer comprises high density polyethylene or a mixture of high density polyethylene and petroleum resin.   The multilayer sheet according to claim 2, wherein the petroleum resin is a polymer obtained using dicyclopentadiene.   The multilayer sheet according to any one of claims 1 to 3, wherein the water vapor barrier layer further contains an inorganic filler.   The compound having the structural unit represented by the formula (1) -1, the structural unit represented by the formula (1) -2, and the structural unit represented by the formula (1) -3 is styrene-isobutylene. The multilayer sheet according to any one of claims 1 to 4, which is a styrene block copolymer.   The multilayer sheet according to any one of claims 1 to 5, wherein the polyolefin-based resin is a high-density polyethylene.   The multilayer sheet according to any one of claims 1 to 6, wherein at least one surface layer and the water vapor barrier layer are stacked adjacent to each other.   The multilayer sheet according to any one of claims 1 to 7, wherein the surface layer comprises only high-density polyethylene, or includes a mixture of high-density polyethylene and polypropylene. The surface layer further includes a structural unit represented by the following formula (2) -1, a structural unit represented by the following formula (2) -2, and a structural unit represented by the following formula (2) -3. The multilayer sheet according to any one of claims 1 to 8, comprising a compound having:

(Wherein, R ⁵ and R ⁶ are each independently an alkyl group having 1 to 4 carbon atoms, and R ⁷ and R ⁸ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. , O and p are each independently an integer of 1 or more, and * represents a bond.)   The multilayer sheet according to any one of claims 1 to 9, comprising two water vapor barrier layers, wherein the water vapor barrier layers are laminated adjacent to the surface layer, respectively.   The multilayer sheet according to claim 1, wherein the thickness of the multilayer sheet is 500 μm or more and 1500 μm or less. The tensile impact strength of the multilayer sheet is 110 kJ / m ² or more, the multilayer sheet according to any one of claims 1 to 11.   The multilayer sheet according to any one of claims 1 to 12, wherein an impact strength of the multilayer sheet with a DuPont drop impact tester is 1.5 J or more.   The multilayer sheet according to any one of claims 7 to 13, 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 14, wherein the multilayer sheet has an oxygen permeation amount under a condition of 25 ° C and 60% RH of 0.35 cc / m ² · day or less.   A tray formed by molding the multilayer sheet according to claim 1.   A package comprising the tray according to claim 16 and a lid.

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