Sheet for press-through package and press-through package

Abstract

To provide a sheet for a press-through package using a polyolefin resin that can demonstrate excellent imaging clarity.SOLUTION: A sheet for a press-through package comprises: an outer layer (A) mainly composed of a polypropylene resin; and an inner layer (B) adjacent to the outer layer (A). The inner layer (B) contains a high-density polyethylene resin and a low-density polyethylene resin, and an arithmetic mean height (Sa) of the surface of the outer layer (A) is 700 nm or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a sheet for a press-through package and a press-through package. [Background technology]

[0002] In the pharmaceutical and food packaging field, PTPs (press-through packages) are used to package solid drugs such as capsules and tablets.

[0003] PTP is a type of packaging in which a pocket for storing solid agents such as capsules is formed, for example, by applying pressure forming, vacuum forming, plug forming, etc. to a transparent sheet, and after storing the capsules in the pocket, a foil or film made of a material that can be easily torn or opened by hand, such as aluminum foil, is laminated as a lid material to integrate the two. By using PTP, the solid agents or food stored in the pocket of the transparent sheet can be directly confirmed with the naked eye before opening, and when opening, the contents can be easily removed by pressing the solid agents in the pocket with a finger to break the lid material.

[0004] Polyvinyl chloride (hereinafter sometimes referred to as "PVC") has traditionally been used as the raw material for the sheets used in PTPs, due to its excellent thermoformability, rigidity at room temperature, impact resistance, transparency, etc. However, PVC has problems such as generating hydrogen chloride gas depending on the combustion method, which deteriorates the combustion furnace and causes environmental pollution. In addition, PVC sometimes has insufficient moisture resistance, and there has been a demand for an alternative material to PVC from the perspective of long-term storage of contents.

[0005] The use of polypropylene resin and polyethylene resin as alternative materials to PVC is being considered. For example, Patent Document 1 describes: (A) a polypropylene resin having a density of 0.935 g / cm3 as measured according to JIS K7112; 3The present invention discloses a polyolefin-based sheet having a layer (I) formed from a thermoplastic resin composition containing the above polyethylene resin, (B) a crystal nucleating agent, (C) at least one thermoplastic resin selected from the group consisting of petroleum resins, terpene resins, coumarone-indene resins, rosin-based resins, and hydrogenated derivatives thereof, and (D) a thermoplastic resin that is incompatible with (A) and has a storage modulus (E') at 24°C of 1000 MPa or more.

[0006] Patent Document 2 discloses a multilayer film including an inner layer and a base layer, in which the inner layer and the base layer are laminated together, and in which, when the peel strength of the inner layer is peeled from the base layer in the multilayer film is A and the breaking strength of the inner layer in the multilayer film is B, A is equal to or greater than B. Patent Document 2 discloses an example in which the inner layer is made of polypropylene and the base layer contains polypropylene, polyethylene, and the like. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2021-161189 A [Patent Document 2] JP 2022-100097 A Summary of the Invention [Problem to be solved by the invention]

[0008] As described above, the PTP is formed by forming a pocket portion for storing a solid agent such as a capsule in a press-through package sheet, storing the capsule or tablet in the pocket portion, and then laminating a lid material such as aluminum foil. In addition to transparency for enhancing the visibility of the capsule or tablet contained therein, the press-through package sheet may be required to have image clarity that allows the letters or patterns printed on the inner surface of the lid material such as aluminum foil to be clearly visible. However, the image clarity of conventional press-through package sheets may be insufficient, and improvements have been required.

[0009] The present inventors have therefore carried out investigations with the aim of providing a press-through packaging sheet using a polyolefin resin and capable of exhibiting excellent image clarity. [Means for solving the problem]

[0010] Examples of specific embodiments of the present invention are given below.

[0011] [1] A plastic bag having an outer layer (A) mainly composed of polypropylene resin and an inner layer (B) adjacent to the outer layer (A), The inner layer (B) contains a high-density polyethylene resin and a low-density polyethylene resin, A sheet for press-through packaging, wherein the arithmetic mean height (Sa) of the surface of the outer layer (A) is 700 nm or less. [2] The sheet for press-through packaging according to [1], wherein the inner layer (B) further contains a polypropylene resin. [3] The sheet for press-through packaging according to [1] or [2], wherein the content of the high-density polyethylene resin in the inner layer (B) is 60 mass% or less based on the total mass of the inner layer (B). [4] The press-through packaging sheet according to any one of [1] to [3], wherein the high-density polyethylene resin has a melt flow rate of 0.3 g / 10 min or more, measured at a measurement temperature of 190° C. and a measurement load of 2.16 kg. [5] The sheet for press-through packaging according to any one of [1] to [4], wherein the inner layer (B) contains a tackifier resin. [6] The sheet for press-through packaging according to any one of [1] to [5], wherein the outer layer (A) contains a tackifier resin. [7] The sheet for press-through packaging according to any one of [1] to [6], wherein the content of the low-density polyethylene in the inner layer (B) is 20 to 70 mass% based on the total mass of the inner layer (B). [8] The sheet for press-through packaging according to any one of [1] to [7], wherein the outer layer (A) has a thickness of 15 μm or more. [9] The water vapor transmission rate measured at 40°C and 90% relative humidity in accordance with JIS K7129-2:2019 is 0.6g / (m 2 The sheet for press-through packaging according to any one of [1] to [8], wherein the time required for the sheet to be used is within 24 hours.

[10] The sheet for press-through packaging according to any one of [1] to [9], having a total haze of 33% or less.

[11] The sheet for press-through packaging according to any one of [1] to

[10] , having an external haze of 30% or less.

[12] The sheet for press-through packaging according to any one of [1] to

[11] , wherein at least one selected from the group consisting of high-density polyethylene resins and low-density polyethylene resins is biomass polyethylene.

[13] The press-through package sheet according to any one of [1] to

[12] , which is for pharmaceutical packaging.

[14] A press-through package comprising the sheet for press-through packaging according to any one of [1] to

[13] and a lid material in combination.

[15] A method for producing a laminated laminated laminate comprising co-extruding a resin composition for forming an outer layer (A) containing a polypropylene resin as a main component and a resin composition for forming an inner layer (B) containing a high-density polyethylene resin and a low-density polyethylene resin, and laminating the outer layer (A) and the inner layer (B); A method for producing a sheet for press-through packaging, in which the arithmetic mean height (Sa) of the surface of the outer layer (A) after lamination is 700 nm or less. Effect of the Invention

[0012] According to the present invention, a press-through package sheet using a polyolefin resin and capable of exhibiting excellent image clarity can be obtained. Also, according to the present invention, a press-through package can be provided in which characters and patterns printed on the inner surface of the lid material can be clearly seen. [Brief description of the drawings]

[0013] [Figure 1]FIG. 1 is a cross-sectional view illustrating one embodiment of a sheet for press-through packaging. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention will be described in detail below. The following description may be based on a representative embodiment or a specific example, but the present invention is not limited to such an embodiment. In this specification, when "X to Y" (X and Y are any numbers) is expressed, it includes "X or more and Y or less" as well as "preferably greater than X" or "preferably smaller than Y" unless otherwise specified. In addition, when "X or more" (X is any number) or "Y or less" (Y is any number) is expressed, it also includes "preferably greater than X" or "preferably less than Y". In the following description, "film" and "sheet" are not clearly distinguished from each other, and when "film" is referred to, it includes "sheet", and when "sheet" is referred to, it includes "film".

[0015] (Press-through packaging sheet) The present embodiment relates to a press-through package sheet (hereinafter also referred to as "the present press-through package sheet") comprising an outer layer (A) mainly composed of polypropylene resin, and an inner layer (B) adjacent to the outer layer (A), the inner layer (B) containing a high-density polyethylene resin and a low-density polyethylene resin, and the arithmetic mean height (Sa) of the surface of the outer layer (A) is 700 nm or less.

[0016] In this specification, "main component" means the resin that has the highest mass proportion among the resins constituting each layer, and can be assumed to account for, for example, 50 mass% or more, 60 mass% or more, 70 mass% or more, 80 mass% or more, 90 mass% or more, or 100 mass% of the resins constituting each layer.

[0017] The arithmetic mean height (Sa) of the surface of the outer layer (A) is preferably 700 nm or less, more preferably 600 nm or less, even more preferably 500 nm or less, even more preferably 400 nm or less, even more preferably 300 nm or less, and particularly preferably 250 nm or less. The lower limit of the arithmetic mean height (Sa) of the surface of the outer layer (A) is not particularly limited, and may be 0 nm.

[0018] As shown in FIG. 1, the press-through package sheet 10 includes an outer layer 4 (outer layer (A)) and an inner layer 2 (inner layer (B)) adjacent to the outer layer 4. The press-through package sheet 10 may include one outer layer 4 and one inner layer 2, or may include the outer layer 4, the inner layer 2, and the outer layer 4 in this order. The outer layer 4 and the inner layer 2 are preferably laminated so as to be in direct contact with each other, and the press-through package sheet 10 is more preferably a co-extruded sheet. By laminating the outer layer 4 and the inner layer 2 so as to be in direct contact with each other, the transparency of the press-through package sheet can be more effectively increased, and further, the press-through package sheet can be made thinner. In addition, by forming the press-through package sheet 10 from the outer layer 4 and the inner layer 2, a press-through package sheet having barrier properties, formability, adhesion to a lid material such as aluminum foil, and the like can be obtained.

[0019] The present press-through package sheet may be composed of two layers, an outer layer (A) and an inner layer (B), may be a multi-layer sheet having multiple outer layers (A) and / or inner layers (B), or may be a multi-layer sheet having layers other than the outer layer (A) and the inner layer (B). Examples of laminated structures include outer layer (A) / inner layer (B), outer layer (A) / other layer / inner layer (B), outer layer (A) / inner layer (B) / outer layer (A), outer layer (A) / other layer / inner layer (B) / other layer / outer layer (A), outer layer (A) / inner layer (B) / outer layer (A) / other layer, other layer / outer layer (A) / inner layer (B) / outer layer (A) / other layer, outer layer (A) / inner layer (B) / outer layer (A) / other layer, other layer ...other layer, other layer / inner layer (B) / other layer / outer layer (A) / other layer / inner layer (B) / other layer, and other layer / inner layer (B) / other layer / outer layer (A) / other layer / inner layer (B) / other layer.

[0020] Since the press-through package sheet has the above-mentioned configuration, it can exhibit excellent image clarity. Specifically, in a press-through package formed using the press-through package sheet, the characters and patterns printed on the inner surface of the lid can be clearly seen. For this reason, for example, by printing the product name and warnings on the inner surface of the lid, it is possible to provide appropriate information to the subject and caregiver who will be vaccinated with the capsule or tablet. In addition, if a delicate pattern is applied to the inner surface of the lid, it is possible to improve the design of the press-through package.

[0021] The image clarity (optical comb slit width 0.5 mm) of the press-through package sheet is preferably 3% or more, more preferably 5% or more, more preferably 10% or more, even more preferably 15% or more, even more preferably 20% or more, even more preferably 25% or more, and particularly preferably 30% or more. The upper limit of the image clarity (optical comb slit width 0.5 mm) of the press-through package sheet is not particularly limited and may be 100%. The image clarity of the press-through package sheet is a value measured in accordance with JIS K7374:2007. For example, ICM-1T (manufactured by Suga Test Instruments) can be used as an image clarity measuring device. Note that image clarity is also called image sharpness.

[0022] In conventional press-through package sheets, when multiple layers are laminated, fine irregularities may occur between the inner layer and the outer layer due to differences in the resin types constituting each layer. However, in the present press-through package sheet, the occurrence of fine irregularities between the inner layer and the outer layer has been successfully suppressed. In this embodiment, the arithmetic mean height (Sa) of the surface of the outer layer (A) is set to a predetermined value or less by suppressing the occurrence of fine irregularities between the inner layer and the outer layer, and as a result, a press-through package sheet with excellent image clarity has been successfully obtained. In this embodiment, the arithmetic mean height (Sa) of the surface of the outer layer (A) can be adjusted, for example, by appropriately controlling the viscosity and compounding ratio of the resin types constituting the inner layer and the outer layer.

[0023] In addition, since the press-through package sheet has the above-mentioned structure, it also has excellent barrier properties. Specifically, when the water vapor transmission rate of the press-through package sheet is kept low, the barrier properties can be evaluated as being good. The water vapor transmission rate of the press-through package sheet is 0.8 g / (m 2 24 hours) or less, and 0.6g / (m 2 It is more preferable that the water vapor transmission rate of the press-through packaging sheet is 0 g / (m 2 The water vapor transmission rate of the press-through package sheet is a value measured at a temperature of 40° C. and a relative humidity of 90% in accordance with JIS K7129-2:2019. As a measuring device for the water vapor transmission rate, for example, PERMATRAN W 3 / 31 (manufactured by MOCON) can be used.

[0024] Furthermore, this press-through packaging sheet also has excellent transparency. There is concern that the transparency may decrease by mixing polyethylene resin and polypropylene resin in the inner layer (B), but this press-through packaging sheet keeps the haze value low and achieves a high total light transmittance. Note that transparency and image clarity are different evaluation indices, and there are cases where image clarity is poor even if transparency is high.

[0025] The total light transmittance of the sheet for press-through packaging is preferably 70% or more, more preferably 80% or more, and even more preferably 85% or more. The upper limit of the total light transmittance of the sheet for press-through packaging is not particularly limited and may be 100%. If the total light transmittance of the sheet for press-through packaging is within the above range, the design of the press-through package can be improved, and the visibility of the contents can be improved. The total light transmittance of the sheet for press-through packaging is a value measured in accordance with JIS K7136:2000.

[0026] The total haze of the press-through package sheet is preferably 50% or less, more preferably 45% or less, even more preferably 40% or less, even more preferably 35% or less, even more preferably 33% or less, and particularly preferably 30% or less. The lower limit of the total haze of the press-through package sheet is not particularly limited and may be 0%. If the total haze of the press-through package sheet is within the above range, the design of the press-through package can be improved, and the visibility of the contents can be further improved. The total haze of the press-through package sheet is a value measured in accordance with JIS K7136:2000.

[0027] The external haze of the press-through package sheet is preferably 30% or less, more preferably 25% or less, even more preferably 20% or less, even more preferably 15% or less, and particularly preferably 10% or less. The lower limit of the external haze of the press-through package sheet is not particularly limited and may be 0%. If the external haze of the press-through package sheet is within the above range, the image clarity of the press-through package sheet can be more effectively improved while increasing the transparency of the press-through package sheet. The external haze of the press-through package sheet is a value measured in accordance with JIS K7136:2000.

[0028] The internal haze of the press-through package sheet is preferably 50% or less, more preferably 40% or less, even more preferably 30% or less, even more preferably 28% or less, and particularly preferably 25% or less. The lower limit of the internal haze of the press-through package sheet is not particularly limited and may be 0%. If the internal haze of the press-through package sheet is within the above range, the design of the press-through package can be improved, and the visibility of the contents can be further improved. The internal haze of the press-through package sheet is a value measured in accordance with JIS K7136:2000.

[0029] The total thickness of the press-through package sheet is preferably 10 μm or more, more preferably 15 μm or more, and even more preferably 20 μm or more. The total thickness of the press-through package sheet is preferably 1000 μm or less, more preferably 900 μm or less, and even more preferably 800 μm or less. By setting the total thickness of the press-through package sheet within the above range, the barrier property and moldability can be more effectively improved.

[0030] In the present press-through package sheet, from the viewpoint of barrier properties and image clarity, it is preferable that the thickness of the inner layer (B) is equal to or greater than the thickness of the outer layer (A). In particular, when biomass polyethylene is used for the inner layer (B), the biomass degree of the press-through package sheet can be increased by increasing the ratio of the inner layer (B) in the press-through package sheet. Specifically, when the thickness of the outer layer (A) is 1, the thickness of the inner layer (B) is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more. In addition, the upper limit of the thickness of the inner layer (B) is not particularly limited, but when the thickness of the outer layer (A) is 1, the thickness of the inner layer (B) is preferably 20 or less, more preferably 15 or less, even more preferably 10 or less, and especially preferably 8 or less. In addition, when the press-through package sheet has a plurality of outer layers (A) and inner layers (B), the above thickness is the thickness of each layer.

[0031] The present invention may also relate to a roll-shaped body obtained by winding up a press-through package sheet into a roll. Since the press-through package sheet has appropriate strength and flexibility, it can be stored or distributed in the form of a roll.

[0032] <Outer layer (A)> The outer layer (A) constituting the present press-through packaging sheet is a layer containing a polypropylene resin as a main component. The outer layer (A) preferably further contains a tackifier resin.

[0033] The thickness of the outer layer (A) is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. The thickness of the outer layer (A) is preferably 200 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less. By making the thickness of the outer layer (A) within the above range, the adhesion to the lid material and the moldability can be more effectively improved.

[0034] From the viewpoint of preventing the unevenness occurring between the inner layer and the outer layer from being transferred to the surface of the outer layer (A), the thickness of the outer layer (A) is preferably 15 μm or more, more preferably 20 μm or more, more preferably 25 μm or more, more preferably 30 μm or more, more preferably 35 μm or more, and particularly preferably 40 μm or more.

[0035] <<Polypropylene resin>> The polypropylene resin may be a polypropylene having a single composition, i.e., a propylene homopolymer, or may be a random copolymer or a block copolymer in which propylene is copolymerized with a copolymerization component. In addition, a mixture of these may also be used as the polypropylene resin.

[0036] The copolymerization component is typically, for example, ethylene or 1-butene, with ethylene being preferred.

[0037] In addition, when the above-mentioned copolymer is used, the content of the copolymerization component in the copolymer is preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and even more preferably 1.5% by mass or more, based on the total mass of the copolymer. In addition, the content of the copolymerization component is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less, based on the total mass of the copolymer. If the content of the copolymerization component in the copolymer is within the above range, it is possible to impart suitable barrier properties and transparency to the sheet while maintaining good film-forming properties.

[0038] As the polypropylene resin, homopolypropylene consisting of a single component and propylene-ethylene random copolymer are more preferable, and homopolypropylene is particularly preferable, because they can impart suitable barrier properties and transparency to the sheet while maintaining good film-forming properties.

[0039] The polymerization method for the polypropylene resin is not particularly limited, and may be carried out by a conventional method. The catalyst used in the polymerization is also not particularly limited, and may be any of the conventional catalysts.

[0040] The melt flow rate (hereinafter also referred to as "MFR") of the polypropylene resin measured in accordance with JIS K7210:2014 at 230°C and a load of 2.16 kg is preferably 0.3 g / 10 min or more, more preferably 0.5 g / 10 min or more, and even more preferably 0.8 g / 10 min or more. The melt flow rate at 230°C and a load of 2.16 kg is preferably 20 g / 10 min or less, more preferably 10 g / 10 min or less, and even more preferably 8 g / 10 min or less. If the MFR of the polypropylene resin is within the above range, stable film-forming properties are obtained, and a press-through packaging sheet having good mechanical properties is easily obtained.

[0041] The density of polypropylene resin measured according to JIS K7112:1999D is 0.850 to 0.950 g / cm 3 It is preferable that the density is 0.870 to 0.930 g / cm 3 More preferably, it is 0.890 to 0.910 g / cm 3 By setting the density of the polypropylene resin within the above range, the barrier property of the press-through packaging sheet can be more effectively improved.

[0042] The number average molecular weight (Mn) of the polypropylene resin is preferably 30,000 or more, more preferably 50,000 or more. There is no particular upper limit to the number average molecular weight (Mn) of the polypropylene resin, but from the viewpoint of extrusion moldability, it is preferably 200,000 or less, particularly 150,000 or less. By setting the number average molecular weight (Mn) of the polypropylene resin within the above range, stable film formability can be obtained, and a press-through packaging sheet with good mechanical properties can be easily obtained.

[0043] The weight average molecular weight (Mw) of the polypropylene resin is preferably 200,000 or more, more preferably 250,000 or more, and even more preferably 300,000 or more. The weight average molecular weight (Mw) of the polypropylene resin is preferably 1,500,000 or less, and more preferably 1,000,000 or less. By setting the weight average molecular weight (Mw) of the polypropylene resin within the above range, stable film formability is obtained, and a press-through packaging sheet having good mechanical properties is easily obtained.

[0044] The molecular weight distribution (Mw / Mn) calculated from the weight average molecular weight (Mw) and number average molecular weight (Mn) of the polypropylene resin is preferably 3.5 or more, more preferably 4.0 or more, and even more preferably 4.5 or more. The molecular weight distribution (Mw / Mn) is preferably 20 or less, and more preferably 15 or less. By making the molecular weight distribution (Mw / Mn) equal to or more than the lower limit, the molding processability of the sheet is improved and the tearing of the sheet is easily suppressed. By making the molecular weight distribution (Mw / Mn) equal to or less than the upper limit, the inclusion of components with extremely low molecular weights can be suppressed, and the bleeding of components with extremely low molecular weights and the formation of unmelted components with extremely high molecular weights during molding can be suppressed. Here, the weight average molecular weight (Mw), number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) can be calculated using a high temperature GPC system (Viscotek triple detector HT-GPC model SG system) manufactured by Malvern Instruments, using orthodichlorobenzene as the solvent, a measurement temperature of 140°C, RI detector (reference flow method) and polystyrene equivalent molecular weight.

[0045] The content of the polypropylene resin is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, based on the total mass of the outer layer (A). The content of the polypropylene resin is preferably 99% by mass or less, more preferably 98% by mass or less, based on the total mass of the outer layer (A). By setting the content of the polypropylene resin within the above range, the adhesion and moldability of the press-through package sheet to the lid material tend to be improved. Furthermore, by setting the content of the polypropylene resin within the above range, good film-forming properties and impact resistance can be maintained, and the interlayer strength between the outer layer (A) and the inner layer (B) can be increased.

[0046] <<Tackifying resin>> The outer layer (A) preferably further contains a tackifier resin in addition to the polypropylene resin.

[0047] Examples of the tackifier resin include petroleum resins, rosin resins such as rosin diol resins and rosin ester resins, terpene resins, phenol resins, xylene resins, coumarone resins, chroman-indene resins, ketone resins and modified resins (hydrogenated derivatives) thereof, and acrylic oligomers. The weight average molecular weight of the acrylic oligomer is not particularly limited, but is preferably 1000 to 30000, more preferably 3000 to 15000. Among them, the tackifier resin preferably contains at least one selected from the group consisting of petroleum resins, terpene resins, chroman-indene resins, rosin resins, and hydrogenated derivatives thereof, and is particularly preferably a terpene resin or a petroleum resin.

[0048] Examples of the petroleum resin include petroleum resins such as C5 petroleum resins, C9 petroleum resins, C5-C9 copolymer petroleum resins, alicyclic hydrocarbon petroleum resins such as dicyclopentadiene petroleum resins, and hydrogenated derivatives thereof. Among these, hydrogenated derivatives of C9 petroleum resins are preferred.

[0049] Examples of the terpene resin include terpene resins such as α-pinene polymers, β-pinene polymers, and dipentene polymers, and modified terpene resins such as terpene phenol resins, styrene-modified terpene resins, and hydrogenated terpene resins.

[0050] The coumarone-indene resin may be, for example, a thermoplastic synthetic resin obtained by purifying a 160 to 180° C. fraction of tar and polymerizing it with coumarone having 8 carbon atoms and indene having 9 carbon atoms as main monomers.

[0051] Examples of the rosin-based resin include unmodified rosins such as tall rosin, gum rosin, and wood rosin, polymerized rosin, disproportionated rosin, hydrogenated rosin, maleic acid-modified rosin, and fumaric acid-modified rosin, as well as esterified rosin resins obtained by modifying these with glycerin, pentaerythritol, ethylene glycol, or the like.

[0052] As the tackifier resin, it is preferable to use a hydrogenated derivative from the viewpoint of exhibiting good compatibility when mixed with polypropylene resin and further improving color tone, thermal stability, barrier properties, etc. In particular, it is preferable to use a petroleum resin or terpene resin having a hydrogenation rate (hydrogenation rate) of 95% or more and substantially free of polar groups such as hydroxyl groups, carboxy groups, and halogens, or unsaturated bonds such as double bonds, and it is more preferable to use a petroleum resin.

[0053] The softening point of the tackifier resin is preferably 80°C or higher, more preferably 90°C or higher, and even more preferably 100°C or higher. The softening point of the tackifier resin is preferably 150°C or lower. When the softening point of the tackifier resin is within the above range, the compatibility of the tackifier resin is increased, and a sheet with excellent transparency is easily obtained. When the softening point of the thermoplastic resin is within the above range, blocking of the raw material pellets during sheet formation can be prevented, and productivity tends to be good.

[0054] The content of the tackifier resin is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, based on the total mass of the outer layer (A). The content of the tackifier resin is preferably 40% by mass or less, more preferably 30% by mass or less, based on the total mass of the outer layer (A). In particular, the content of the terpene resin or petroleum resin is preferably within the above range. By setting the content of the tackifier resin within the above range, it is possible to maintain good film-forming properties and impact resistance, and also to more effectively increase the interlayer adhesion between the outer layer (A) and the inner layer (B).

[0055] <Inner layer (B)> The inner layer (B) constituting the present press-through packaging sheet is a layer containing a high-density polyethylene resin and a low-density polyethylene resin.

[0056] The inner layer (B) may further contain a polypropylene resin. For example, when waste materials such as scraps generated during the production of the press-through packaging sheet are collected and reused, the inner layer (B) preferably contains a polypropylene resin, which is the same resin as the main component of the outer layer (A). In addition, by the inner layer (B) containing a polypropylene resin, which is the same resin as the main component of the outer layer (A), interlayer adhesion can also be effectively improved. In addition, the inner layer (B) preferably further contains a tackifier resin.

[0057] The thickness of the inner layer (B) is preferably 50 μm or more, more preferably 60 μm or more, and even more preferably 70 μm or more. The thickness of the inner layer (B) is preferably 400 μm or less, more preferably 350 μm or less, and even more preferably 300 μm or less. By setting the thickness of the inner layer (B) within the above range, it is possible to more effectively improve moldability and barrier properties while improving image clarity.

[0058] <<Polyethylene resin>> The inner layer (B) contains a high-density polyethylene resin and a low-density polyethylene resin (hereinafter, the high-density polyethylene resin and the low-density polyethylene resin are collectively referred to as "polyethylene resin"). The polyethylene resin may be a polyethylene homopolymer, or a polyethylene copolymer, which is a copolymer of ethylene and a monomer component other than ethylene. A mixture of these may also be used as the polyethylene resin. In this specification, when distinguishing between polyethylene resin and polypropylene resin, polyethylene resin is one that contains more than 50% by mass of ethylene units as monomer units constituting the resin, and polypropylene resin is one that contains more than 50% by mass of propylene units as monomer units constituting the resin.

[0059] Examples of the copolymerization component include α-olefin monomers and non-olefin monomers having a functional group, and among these, α-olefin monomers are preferred.

[0060] The α-olefin monomer may be an α-olefin having 3 to 20 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, Examples of the α-olefin monomer include 3-methyl-1-butene, 4-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, and 12-ethyl-1-tetradecene. These may be used alone or in combination of two or more. Among them, it is preferable to use propylene, 1-butene, 1-hexene, and 1-octene as the α-olefin monomer from the viewpoints of industrial availability, various characteristics, and economic efficiency.

[0061] When the above copolymer is used, the content of the copolymerization component in the copolymer is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and even more preferably 0.5% by mass or more, based on the total mass of the copolymer. The content of the copolymerization component is preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 25% by mass or less, and particularly preferably 20% by mass or less, based on the total mass of the copolymer. In particular, it is preferable that the content of the α-olefin monomer is within the above range. If the content of the copolymerization component in the copolymer is within the above range, the moisture resistance and transparency of the press-through package sheet can be further improved.

[0062] As the polyethylene resin, it is preferable to use an ethylene homopolymer or a copolymer of ethylene and at least one kind of α-olefin monomer selected from the group consisting of propylene, 1-butene, 1-hexene, and 1-octene.

[0063] The polymerization method for the polyethylene resin is not particularly limited, and may be any conventional method known in the art. The catalyst used in the polymerization is also not particularly limited, and any conventional catalyst may be used.

[0064] The inner layer (B) contains a high-density polyethylene resin. The density of the high-density polyethylene resin measured in accordance with JIS K7112:1999D is 0.930 g / cm 3 It is preferable that the content is 0.935 g / cm or more. 3 More preferably, it is 0.940 g / cm or more. 3 More preferably, it is 0.945 g / cm or more. 3 It is particularly preferable that the density is 0.930 g / cm or more. 3 Polyethylene resins with a density of 0.980 g / cm3 or higher are called high density polyethylene resins. 3 It is preferable that:

[0065] The content of the high-density polyethylene resin contained in the inner layer (B) is preferably 60% by mass or less, more preferably 55% by mass or less, and even more preferably 50% by mass or less, based on the total mass of the inner layer (B). The content of the high-density polyethylene resin contained in the inner layer (B) is preferably 5% by mass or more, more preferably 10% by mass or more, based on the total mass of the inner layer (B). By making the content of the high-density polyethylene resin in the inner layer (B) equal to or less than the above upper limit, it is possible to suppress the occurrence of fine irregularities between the outer layer (A) and the inner layer (B), and as a result, it is easy to make the arithmetic mean height (Sa) of the surface of the outer layer (A) equal to or less than a predetermined value. By making the content of the high-density polyethylene resin in the inner layer (B) equal to or more than the above lower limit, it is possible to more effectively increase the strength and barrier property of the press-through packaging sheet.

[0066] The melt flow rate (MFR) of the high-density polyethylene resin measured at a measurement temperature of 190°C and a measurement load of 2.16 kg according to JIS K7210:2014 is preferably 0.3 g / 10 min or more, more preferably 0.5 g / 10 min or more, and even more preferably 0.8 g / 10 min or more. The melt flow rate (MFR) of the high-density polyethylene resin measured at a measurement temperature of 190°C and a measurement load of 2.16 kg is preferably 20 g / 10 min or less, more preferably 10 g / 10 min or less, and even more preferably 8 g / 10 min or less. If the MFR of the high-density polyethylene resin is the above-mentioned lower limit value or more, the difference in viscosity during melting between the resin composition forming the outer layer (A) and the resin composition forming the inner layer (B) can be reduced, and the occurrence of fine irregularities between the outer layer (A) and the inner layer (B) can be suppressed. As a result, it is easy to control the arithmetic mean height (Sa) of the surface of the outer layer (A) to a predetermined value or less. When the MFR of the high-density polyethylene resin is equal to or less than the above upper limit, stable film-forming properties are obtained, and a press-through packaging sheet having good mechanical properties is easily obtained.

[0067] The number average molecular weight (Mn) of the high-density polyethylene resin is preferably 5,000 or more, more preferably 7,500 or more, and even more preferably 10,000 or more. There is no particular upper limit to the number average molecular weight (Mn) of the high-density polyethylene resin, but from the viewpoint of extrusion moldability and film formability, it is preferably 150,000 or less, and more preferably 100,000 or less. By setting the number average molecular weight (Mn) of the high-density polyethylene resin within the above range, stable film formability can be obtained and the occurrence of fine irregularities between the outer layer (A) and the inner layer (B) can be suppressed, and as a result, it becomes easy to set the arithmetic mean height (Sa) of the surface of the outer layer (A) to a predetermined value or less.

[0068] The weight average molecular weight (Mw) of the high-density polyethylene resin is preferably 50,000 or more, more preferably 100,000 or more, and even more preferably 200,000 or more. There is no particular upper limit to the weight average molecular weight (Mw) of the high-density polyethylene resin, but from the viewpoint of extrusion moldability and film formability, it is preferably 2,000,000 or less, and more preferably 1,000,000 or less. By setting the weight average molecular weight (Mw) of the high-density polyethylene resin within the above range, stable film formability can be obtained and the occurrence of fine irregularities between the outer layer (A) and the inner layer (B) can be suppressed, and as a result, it becomes easy to set the arithmetic mean height (Sa) of the surface of the outer layer (A) to a predetermined value or less.

[0069] The molecular weight distribution (Mw / Mn) calculated from the weight average molecular weight (Mw) and number average molecular weight (Mn) of the high density polyethylene resin is preferably 2 or more, more preferably 3 or more, and even more preferably 4 or more. The molecular weight distribution (Mw / Mn) is preferably 50 or less, more preferably 30 or less. By setting the molecular weight distribution (Mw / Mn) to the above lower limit or more, the molding processability of the sheet is improved and tearing of the sheet is easily suppressed. By setting the molecular weight distribution (Mw / Mn) to the above upper limit or less, the inclusion of components with extremely low molecular weights can be suppressed, and the bleeding of components with extremely low molecular weights and the formation of unmelted components with extremely high molecular weights during molding can be suppressed. Here, the weight average molecular weight (Mw), number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) can be calculated using a high temperature GPC system (Viscotek triple detector HT-GPC model SG system) manufactured by Malvern Instruments, using orthodichlorobenzene as the solvent, a measurement temperature of 140°C, RI detector (reference flow method) and polystyrene equivalent molecular weight.

[0070] The inner layer (B) contains a low-density polyethylene resin. The density of the low-density polyethylene resin measured in accordance with JIS K7112:1999D is 0.930 g / cm 3 Preferably, it is less than 0.928 g / cm 3 More preferably, it is 0.926 g / cm or less. 3 More preferably, it is 0.925 g / cm or less. 3 It is particularly preferable that the density is 0.930 g / cm or less. 3 Polyethylene resins with a density less than 0.900 g / cm are called low-density polyethylene resins. 3 More preferably, it is equal to or greater than this.

[0071] The content of the low-density polyethylene resin in the inner layer (B) is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, based on the total mass of the inner layer (B). The content of the low-density polyethylene resin is preferably 70% by mass or less, more preferably 65% ​​by mass or less, and even more preferably 60% by mass or less, based on the total mass of the inner layer (B). By setting the content of the low-density polyethylene resin in the inner layer (B) within the above range, it is possible to suppress the occurrence of fine irregularities between the outer layer (A) and the inner layer (B), which results in the arithmetic mean height (Sa) of the surface of the outer layer (A) being easily set to a predetermined value or less, and further has the advantage of facilitating processing when forming a pocket portion of a press-through package.

[0072] When the content of the high-density polyethylene resin contained in the inner layer (B) is P and the content of the low-density polyethylene resin contained in the inner layer (B) is Q, the value of P / Q is preferably 3 or less, more preferably 2.5 or less, and even more preferably 2 or less. Moreover, the value of P / Q is preferably 0.1 or more, more preferably 0.3 or more, and even more preferably 0.5 or more. By setting the value of P / Q within the above range, the image clarity, strength, and barrier properties of the press-through packaging sheet can be more effectively improved.

[0073] The melt flow rate (MFR) of the low-density polyethylene resin measured in accordance with JIS K7210:2014 at a measurement temperature of 190°C and a measurement load of 2.16 kg is preferably 0.2 g / 10 min or more, more preferably 0.4 g / 10 min or more, and even more preferably 0.5 g / 10 min or more. The melt flow rate (MFR) of the low-density polyethylene resin measured at a measurement temperature of 190°C and a measurement load of 2.16 kg is preferably 10 g / 10 min or less, more preferably 8 g / 10 min or less, and even more preferably 5 g / 10 min or less. If the MFR of the low-density polyethylene resin is within the above range, stable film formability can be obtained, and a press-through packaging sheet having good mechanical properties can be easily obtained. Furthermore, when the MFR of the low-density polyethylene resin is within the above range, the generation of fine irregularities between the outer layer (A) and the inner layer (B) can be suppressed, and as a result, the arithmetic mean height (Sa) of the surface of the outer layer (A) can be easily controlled to a predetermined value or less.

[0074] The number average molecular weight (Mn) of the low-density polyethylene resin is preferably 5,000 or more, more preferably 7,500 or more, and even more preferably 10,000 or more. There is no particular upper limit to the number average molecular weight (Mn) of the low-density polyethylene resin, but from the viewpoint of extrusion moldability and film formability, it is preferably 150,000 or less, and more preferably 100,000 or less. By setting the number average molecular weight (Mn) of the low-density polyethylene resin within the above range, stable film formability can be obtained and the occurrence of fine irregularities between the outer layer (A) and the inner layer (B) can be suppressed, and as a result, it becomes easy to set the arithmetic mean height (Sa) of the surface of the outer layer (A) to a predetermined value or less.

[0075] The weight average molecular weight (Mw) of the low-density polyethylene resin is preferably 50,000 or more, more preferably 100,000 or more, and even more preferably 150,000 or more. There is no particular upper limit to the weight average molecular weight (Mw) of the low-density polyethylene resin, but from the viewpoint of extrusion moldability and film formability, it is preferably 2,000,000 or less, and more preferably 1,000,000 or less. By setting the weight average molecular weight (Mw) of the low-density polyethylene resin within the above range, stable film formability can be obtained and the occurrence of fine irregularities between the outer layer (A) and the inner layer (B) can be suppressed, and as a result, it becomes easy to set the arithmetic mean height (Sa) of the surface of the outer layer (A) to a predetermined value or less.

[0076] The molecular weight distribution (Mw / Mn) calculated from the weight average molecular weight (Mw) and number average molecular weight (Mn) of the low density polyethylene resin is preferably 2 or more, more preferably 3 or more, and even more preferably 4 or more. The molecular weight distribution (Mw / Mn) is preferably 50 or less, more preferably 30 or less. By setting the molecular weight distribution (Mw / Mn) to the above lower limit or more, the molding processability of the sheet is improved and tearing of the sheet is easily suppressed. By setting the molecular weight distribution (Mw / Mn) to the above upper limit or less, the inclusion of components with extremely low molecular weights can be suppressed, and the bleeding of components with extremely low molecular weights and the formation of unmelted components with extremely high molecular weights during molding can be suppressed.

[0077] At least one selected from the high-density polyethylene resin and the low-density polyethylene resin may be a petroleum-derived polyethylene resin, but is preferably a biomass polyethylene. In a preferred embodiment, both the high-density polyethylene and the low-density polyethylene are preferably biomass polyethylene. Biomass polyethylene refers to a polyethylene resin that uses at least a part of a biomass-derived (plant-derived) raw material as a raw material and is obtained by chemical or biological synthesis using renewable biomass resources as a raw material. Biopolyethylene has the characteristic that, even if it is incinerated, it does not increase the carbon dioxide concentration in the atmosphere due to the carbon neutrality of biomass.

[0078] The biomass polyethylene preferably uses plant-derived ethylene derived from bioethanol obtained from a plant raw material. That is, the biomass polyethylene is preferably a polymer of a monomer containing biomass-derived ethylene. The biomass polyethylene does not have to contain 100% by mass of biomass-derived ethylene. The monomer as the raw material of the biomass polyethylene may further contain a fossil fuel-derived ethylene monomer and / or a fossil fuel-derived α-olefin monomer, and may further contain a biomass-derived α-olefin monomer. As the biomass-derived α-olefin, it is preferable to use an α-olefin having 3 to 20 carbon atoms, and butylene, hexene, or octene is preferable. Butylene, hexene, or octene can be easily produced by polymerization of ethylene, which is a raw material derived from biomass. The MFR, density, molecular weight, etc. of the biomass polyethylene are preferably the same as the MFR, density, molecular weight, etc. of the above-mentioned polyethylene resin.

[0079] The biomass degree of the inner layer (B) is preferably 10% or more, more preferably 15% or more, and even more preferably 20% or more. The biomass degree of the inner layer (B) may be 100%. Here, the biomass degree (carbon concentration derived from biomass in biomass polyethylene) is a value measured by measuring the content of carbon derived from biomass by radioactive carbon (C14). Since carbon dioxide in the atmosphere contains a certain proportion of C14 (105.5 pMC), it is known that the C14 content in plants that grow by taking in carbon dioxide from the atmosphere is about 105.5 pMC. It is also known that fossil fuels contain almost no C14. Therefore, the proportion of carbon derived from biomass can be calculated by measuring the proportion of C14 contained in the total carbon atoms in the inner layer (B). The biomass degree can be calculated by the following method. "Biomass content of inner layer (B)" (%) = "Biomass content of resin made from biomass resources" (%) x "mass proportion of resin made from biomass resources in inner layer (B)" Increasing the biomass content of the inner layer (B) not only reduces the burden on the environment, but also more effectively enhances the barrier properties of the press-through packaging sheet.

[0080] Specific examples of high-density polyethylene resin products include petroleum-derived polyethylene resins such as Asahi Kasei's "Suntech HD" series, Japan Polypropylene's "Novatec HD" series, and Prime Polymer's "Evolue H" series. Examples of high-density biomass polyethylene include Braskem's "Green Polyethylene" series.

[0081] Specific examples of low-density polyethylene resin products include petroleum-derived polyethylene resins such as the "Suntech LD" series manufactured by Asahi Kasei Corporation and the "Novatec LD" series manufactured by Japan Polypropylene Corporation. Examples of low-density biomass polyethylene include the "Green Polyethylene" series manufactured by Braskem.

[0082] <<Polypropylene resin>> The inner layer (B) preferably contains a polypropylene resin. The polypropylene resin that the inner layer (B) may contain is the same as the polypropylene resin that the outer layer (A) may contain.

[0083] The content of the polypropylene resin is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, based on the total mass of the inner layer (B). The content of the polypropylene resin is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less, based on the total mass of the inner layer (B). By keeping the content of the polypropylene resin within the above range, it is possible to maintain good film-forming properties and impact resistance, and further to increase the interlayer adhesion between the outer layer (A) and the inner layer (B).

[0084] <<Tackifying resin>> The inner layer (B) preferably contains a tackifier resin. When the inner layer (B) contains a tackifier resin, the tackifier resin that the inner layer (B) may contain is the same as the tackifier resin that the outer layer (A) may contain. In this embodiment, the interlayer adhesion between the outer layer (A) and the inner layer (B) can be more effectively improved by containing a tackifier resin in both the outer layer (A) and the inner layer (B).

[0085] The content of the tackifier resin is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, based on the total mass of the inner layer (B). The content of the tackifier resin is preferably 40% by mass or less, more preferably 30% by mass or less, based on the total mass of the inner layer (B). In particular, the content of the terpene resin or petroleum resin is preferably within the above range. By setting the content of the tackifier resin within the above range, it is possible to maintain good film-forming properties and impact resistance, and also to more effectively increase the interlayer adhesion between the outer layer (A) and the inner layer (B).

[0086] <Optional ingredients> Each of the outer layer (A) and the inner layer (B) may contain various additives as necessary. Examples of additives include crystal nucleating agents, heat stabilizers, antioxidants, ultraviolet absorbers, light stabilizers, nucleating agents, antibacterial and antifungal agents, antistatic agents, lubricants, etc. These may be used alone or in combination of two or more.

[0087] Examples of the crystal nucleating agent include dibenzylidene sorbitol (DBS) compounds, 1,3-O-bis(3,4 dimethylbenzylidene) sorbitol, dialkylbenzylidene sorbitol, diacetals of sorbitol having at least one chlorine or bromine substituent, di(methyl- or ethyl-substituted benzylidene) sorbitol, bis(3,4-dialkylbenzylidene) sorbitol having a substituent forming a carbon ring, aliphatic, alicyclic, and aromatic carboxylic acids, dicarboxylic acids, or polybasic polycarboxylic acids, and organic acids such as their anhydrides and metal salts. Metal salt compounds, cyclic bis-phenol phosphates, bicyclic dicarboxylic acids and salt compounds such as disodium bicyclo[2.2.1]heptene dicarboxylate, etc., saturated metal or organic salt compounds of bicyclic dicarboxylates such as bicyclo[2.2.1]heptane dicarboxylate, etc., 1,3:2,4-O-dibenzylidene-D-sorbitol, 1,3:2,4-bis-O-(m-methylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(m-ethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(m-isopropyl benzylidene)-D-sorbitol, 1,3:2,4-bis-O-(mn-propylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(mn-butylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(p-methylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(p-ethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(p-isopropylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(pn-propylbenzylidene)-D-sorbitol, 1,3 :2,4-bis-O-(pn-butylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(2,3-dimethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(2,4-dimethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(2,5-dimethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(3,4-dimethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(3,5-dimethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(2,3-diethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(2,4-diethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(2,5-diethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(3,4-diethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(3,5-diethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(2,4,5-trimethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(3,4,5-trimethyl benzylidene)-D-sorbitol, 1,3:2,4-bis-O-(2,4,5-triethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(3,4,5-triethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(p-methyloxycarbonylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(p-ethyloxycarbonylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(p-isopropyloxycarbonylbenzylidene)-D-sorbitol, 1,3:2,4-bis- O-(on-propyloxycarbonylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(on-butylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(o-chlorobenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(p-chlorobenzylidene)-D-sorbitol, 1,3:2,4-bis-O-[(5,6,7,8,-tetrahydro-1-naphthalene)-1-methylene]-D-sorbitol, 1,3:2,4-bis-O-[(5,6,7,8,-tetrahydro-2-naphthalene)-1-methylene ]-D-sorbitol, 1,3-O-benzylidene-2,4-Op-methylbenzylidene-D-sorbitol, 1,3-Op-methylbenzylidene-2,4-O-benzylidene-D-sorbitol, 1,3-O-benzylidene-2,4-Op-ethylbenzylidene-D-sorbitol, 1,3-Op-ethylbenzylidene-2,4-O-benzylidene-D-sorbitol, 1,3-O-benzylidene-2,4-Op-chlorobenzylidene-D-sorbitol, 1,3-Op-chlorobenzylidene-2,4-O-benzylidene-D-sorbitol, 1,3-O-benzylidene-2,4-O-(2,4-dimethylbenzylidene)-D-sorbitol, 1,3-O-(2,4-dimethylbenzylidene)-2,4-O-benzylidene-D-sorbitol, 1,3-O-benzylidene-2,4-O-(3,4-dimethylbenzylidene)-D-sorbitol, 1,3-O-(3,4-dimethylbenzylidene)-2,4-O-benzylidene-D-sorbitol, 1,3-Op-methyl-benzylidene diacetal compounds such as 1,3-p-ethyl-benzylidene-2,4-p-methylbenzylidene-D-sorbitol, 1,3-p-ethyl-benzylidene-2,4-p-methylbenzylidene-D-sorbitol, 1,3-p-methyl-benzylidene-2,4-op-chlorobenzylidene-D-sorbitol, and 1,3-p-chloro-benzylidene-2,4-op-methylbenzylidene-D-sorbitol; sodium 2,2'-methylene-bis-(4,6-di tert-butylphenyl) phosphate, aluminum bis[2,2'-methylene-bis-(4-6-di-tert-butylphenyl) phosphate], sodium 2,2-methylenebis(4,6-di-tert-butylphenyl) phosphate, fatty acids such as caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, margaric acid, stearic acid, nonadecanoic acid, arachic acid, behenic acid, and montanic acid, fatty acid amides such as oleic acid amide, erucic acid amide, stearic acid amide, and hebenic acid amide, fatty acid metal salts such as magnesium stearate, zinc stearate, and calcium stearate, inorganic particles such as silica, talc, kaolin, and calcium carbide, higher fatty acid esters such as glycerol and glycerin monoester, and similar substances. These may be used alone or in combination of two or more. Among these, fatty acid amides such as oleic acid amide, erucic acid amide, stearic acid amide, and hebenic acid amide, and fatty acid metal salts such as magnesium stearate, zinc stearate, and calcium stearate are particularly preferred.

[0088] Specific examples of crystal nucleating agents include the "Gelall D" series manufactured by New Japan Chemical Co., Ltd., the "Adeka STAB" series manufactured by Asahi Denka Kogyo Co., Ltd., the "HYPERFORM HPN-20E", "HL3-4", and "Millad" series manufactured by Milliken Chemical Co., Ltd., the "IRGACLEAR" series manufactured by BASF, and "Rikemaster CN-001" and "Rikemaster CN-002" manufactured by Riken Vitamin Co., Ltd. Among these, those that are particularly effective in improving transparency include "HYPERFORM HPN-20E" and "HL3-4" manufactured by Milliken Chemical Co., Ltd., and "Rikemaster CN-001" and "Rikemaster CN-002" manufactured by Riken Vitamin Co., Ltd.

[0089] Each of the outer layer (A) and the inner layer (B) may contain other resins in addition to polypropylene resin and polyethylene resin, so long as the effect of the present invention is not impaired. Examples of other resins include polyester resins such as polyethylene terephthalate, polyethylene-2,6-naphthalate, polypropylene terephthalate, and polybutylene terephthalate; polyolefin resins such as cyclopolyolefin and polymethylpentene; cellulose derivatives such as acetyl cellulose, nitrocellulose, acetyl butyl cellulose, ethyl cellulose, and methyl cellulose; vinyl resins such as vinyl acetate and its copolymers, vinyl chloride and its copolymers, and vinylidene chloride and its copolymers; acetal resins such as polyvinyl formal and polyvinyl butyral; acrylic resins such as polyacrylic acid esters and their copolymers, and methacrylic resins such as polymethacrylic acid esters and their copolymers; polystyrene resins; polyamide resins; and polycarbonate resins. These may be composed of one or a combination of two or more.

[0090] When each of the outer layer (A) and the inner layer (B) contains other resins, the content of the other resins is preferably 40 mass% or less, more preferably 30 mass% or less, and even more preferably 20 mass% or less, relative to the total mass of each layer.

[0091] <Arbitrary layer> The press-through packaging sheet may further have an optional layer on the outer layer (A), such as a barrier layer, an adhesive layer, a printing layer, etc.

[0092] For example, the barrier layer preferably contains a fluorine-based resin, such as polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether (EPA), tetrafluoroethylene-ethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), chlorotrifluoroethylene-ethylene copolymer (ECTFE), etc.

[0093] The barrier layer may contain various additives other than the fluorine-based resin, if necessary. Examples of the additives include heat stabilizers, antioxidants, ultraviolet absorbers, light stabilizers, nucleating agents, antibacterial and antifungal agents, antistatic agents, lubricants, etc. These may be used alone or in combination of two or more.

[0094] When the press-through packaging sheet has an adhesive layer, the adhesive layer is preferably a layer that bonds the outer layer (A) and any layer laminated on the outer layer (A). Examples of adhesives constituting such adhesive layers include polyester resins, polyester urethane resins, urethane resins, and epoxy resins. Among them, the adhesive is preferably a polyester resin, a polyurethane resin, or both of these resins, from the viewpoint of increasing adhesion with the outer layer (A).

[0095] When the present press-through packaging sheet has an adhesive layer, it is preferable to coat an adhesive on the outer layer (A) to form an adhesive layer, and then form any optional layer such as a barrier layer.

[0096] (Method of manufacturing press-through package sheet) The method for producing the press-through package sheet preferably includes a step of melt-mixing the resin composition for forming the outer layer (A) containing a polypropylene resin as a main component and the resin composition for forming the inner layer (B) containing a high-density polyethylene resin and a low-density polyethylene resin, respectively, in a single-screw or twin-screw extruder, co-extruding the resin composition through a T-die, and quenching and solidifying the resin composition through a cast roll. This makes it possible to obtain a press-through package sheet having the outer layer (A) and the inner layer (B). The press-through package sheet may be a non-stretched sheet, or may be a stretched sheet obtained by stretching the sheet in a uniaxial or biaxial direction. However, from the viewpoint of formability, the press-through package sheet is preferably a non-stretched sheet. Here, in this specification, the non-stretched sheet means a sheet that is not actively stretched for the purpose of increasing the strength of the sheet, and for example, a sheet that is stretched less than twice as long by a stretching roll during extrusion molding is included in the non-stretched sheet.

[0097] The press-through packaging sheet thus obtained does not require an adhesive layer between the outer layer (A) and the inner layer (B), and can be excellent in productivity and cost. From the viewpoint of adhesion, it is preferable that the outer layer (A) and the inner layer (B) each contain a tackifier resin. It is also preferable that the resin composition for forming the inner layer (B) contains a polypropylene resin.

[0098] (Press-through package manufacturing method) The press-through package sheet can be formed into various shapes by, for example, vacuum forming, pressure forming, pressure vacuum forming, press forming, plug forming, or other thermoforming. For example, the press-through package sheet is suitable for press-through packages because it has excellent barrier properties, formability, and transparency, and can exhibit particularly excellent image clarity. In other words, the press-through package sheet is suitable as a base material for PTP (press-through package). PTP is "a packaging material consisting of a sheet-like base material with a recess (pocket) for inserting tablets or capsules, and a sheet-like lid material that seals the recess, and which allows tablets, etc. to be removed by pressing the recess to open it."

[0099] The method for producing a press-through package includes a step of forming a large number of protruding molded portions (also called "recesses") that form pockets in the sheet for press-through packaging. There are no particular limitations on the inner diameter and depth of the recesses, but for example, the diameter is 5 to 20 mm, and the depth is 1 to 10 mm, and a typical example is a diameter of about 9 mm and a depth of about 4 mm. The number of recesses formed is 500 to 5000 per m. 2 In the step of forming the protruding molded portion (also referred to as a "recess"), the surface thickness constituting the recess may be appropriately controlled, and for example, the central thickness of the side wall portion may be molded to be 30% to 98% of the central thickness of the top wall portion (also referred to as a "bottom surface portion") constituting the recess.

[0100] For example, when manufacturing a PTP base material, the press-through package sheet is heated and softened, and then various molding methods such as plug molding, compressed air molding, vacuum molding, etc. Since the press-through package sheet can be molded with precision even for protruding parts with small diameters, it is particularly useful to employ the plug molding method. In other words, the manufacturing method for the press-through package preferably includes a step of plug molding the press-through package sheet.

[0101] Among the molding methods using plugs, it is preferable to adopt an air-assisted plug molding method that combines air assist and plug molding as a preliminary molding, and a plug pressure molding method that raises and lowers the plug at an appropriate timing during pressure air injection to assist moldability. Among these, it is particularly preferable to adopt an air-assisted plug molding method from the viewpoint of thickness control. For example, when manufacturing a PTP base material, the press-through package sheet is heated and softened with a heating plate before molding, the sheet is sandwiched between a mold, and pressure air is injected while the plug is raised and lowered to form a number of pockets (for example, a diameter of about 9 mm and a depth of about 4 mm) in the sheet surface along the concave shape of the mold. It is preferable that the plug is abutted from the press-through package sheet side of the press-through package sheet.

[0102] In addition to subjecting this press-through packaging sheet to thermoforming, it is also possible to laminate aluminum foil, aluminum vapor deposition film, plastic film (e.g., biaxially oriented polypropylene film, polyamide film, ethylene-vinyl alcohol copolymer film, polyvinylidene chloride film), etc., on the front surface, back surface, or both surfaces of the sheet. It is also possible to form a composite sheet by laminating aluminum foil or various films on the front surface, back surface, or both surfaces of the sheet, and then thermoforming the composite sheet.

[0103] Furthermore, in order to improve the design and secondary processability of the product, the sheet surface may be embossed or matte-finished. In this case, a mirror-like sheet may be prepared and then processed with an embossing roll or matte-finish roll, or the cast roll may be replaced with an embossing roll or matte-finish roll during extrusion molding of the press-through package sheet. As long as the purpose of the present invention is not impaired, the sheet surface may be coated with an antistatic agent, silicone, wax, or the like. In addition, a film may be formed using a surface protection sheet for the purpose of preventing scratches, and a printed layer may also be provided. The means for forming the printed layer may be a known means.

[0104] The PTP base material produced as described above can be combined with a lid material to form a PTP.

[0105] The lid material may be a material generally used for PTPs, such as aluminum foil, film, or other conventionally known material. The contents of the PTP are not particularly limited as long as they can be stored in the pocket, such as tablets or capsules.

[0106] (Press-through package) The present invention also relates to a press-through package formed by combining the above-mentioned press-through package sheet with a lid material. The press-through package is a package obtained by placing contents such as capsules in pockets formed in the press-through package sheet, and then sealing and integrating the pockets with a lid material.

[0107] The contents stored in the press-through package are not particularly limited as long as they can be stored in the pocket, such as tablets and capsules. Examples of the contents include medicines, foods, and supplements. Among them, the contents of the press-through package are preferably medicines, and the press-through package sheet is preferably for use in pharmaceutical packaging. The press-through package sheet is particularly suitable for use in pharmaceutical packaging because it has excellent barrier properties, moldability, and transparency. EXAMPLES

[0108] The features of the present invention will be described in more detail below with reference to examples and comparative examples. The materials, amounts used, ratios, processing contents, processing procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the specific examples shown below.

[0109] <Raw materials> The raw materials used in the examples and comparative examples will be described below.

[0110] [Polypropylene resin] (PP-1): Homopolypropylene (density = 0.90 g / cm 3 , MFR = 2.1g / 10min (2.16kgf, measured at 190℃), MFR = 5.0g / 10min (2.16kgf, measured at 230℃), Mn = 90,000, Mw = 530,000, Mw / Mn = 5.9) (PP-2): Homopolypropylene (density = 0.90 g / cm 3 , MFR = 0.9g / 10min (2.16kgf, measured at 190℃), MFR = 2.3g / 10min (2.16kgf, measured at 230℃) Mn = 110,000, Mw = 620,000, Mw / Mn = 5.4)

[0111] [Polyethylene resin] (PE-1): High density polyethylene (density = 0.952 g / cm 3 , MFR=0.1g / 10min (2.16kgf, measured at 190℃), Mn=22,000, Mw=610,000, Mw / Mn=27.5) (PE-2): High density polyethylene (density = 0.956 g / cm 3 , MFR=0.34g / 10min (2.16kgf, measured at 190℃), Mn=32,000, Mw=470,000, Mw / Mn=15.0) (PE-3): High density polyethylene (density = 0.948 g / cm 3 , MFR=1.0g / 10min (2.16kgf, measured at 190℃), Mn=34,000, Mw=330,000, Mw / Mn=9.7) (PE-4): High density polyethylene (density = 0.953 g / cm 3 , MFR=2.0g / 10min (2.16kgf, measured at 190℃), Mn=39,000, Mw=280,000, Mw / Mn=7.0) (PE-5): Low-density polyethylene (density = 0.923 g / cm 3 , MFR=2.7g / 10min (2.16kgf, measured at 190℃), Mn=22,000, Mw=190,000, Mw / Mn=8.7)

[0112] [Tackifier resin] (Tackifier resin-1): Hydrogenated derivative of C9 petroleum resin (density = 0.999 g / cm 3 , softening point=125℃) (Tackifier resin-2): Terpene resin (density = 0.98 g / cm 3 , softening point=125℃)

[0113] The physical properties of the above raw materials were measured by the following methods. (density) JIS K7112:1999D method (MFR) JIS K7210:2014 method (Mn, Mw, Mw / Mn) The calculation was performed using a high-temperature GPC system (Viscotek triple detector HT-GPC model SG system) manufactured by Malvern Instruments, with the solvent used being orthodichlorobenzene, the measurement temperature being 140° C., the detector being RI (reference flow method), and the molecular weight calculated in terms of polystyrene. (softening point) The softening point was measured using an automatic softening point measuring device (APS-MG2 type manufactured by Meitec Corporation) according to the JIS K2207:1996 method.

[0114] <Example 1> To prepare a resin composition for forming an outer layer, (PP-2) and (tackifier resin-2) were dry-blended in a mixing mass ratio of 90:10, and then kneaded at 230° C. using a 40 mmφ single-screw extruder. To prepare a resin composition for forming an inner layer, (PP-2), (PE-2), (PE-5) and (tackifier resin-2) were dry-blended in a mass ratio of 20:25:40:15, and then kneaded at 230°C using a 40 mmφ single-screw extruder. Each layer was extruded from a T-die so that the thickness ratio of the outer layer to the inner layer was outer layer:inner layer:outer layer=1:10:1, and then quenched with a casting roll at about 45° C. to produce a sheet with a thickness of 250 μm.

[0115] <Examples 2 to 7> A sheet was produced in the same manner as in Example 1, except that the raw material blending composition of the resin composition for forming each layer and the lamination ratio of the outer layer and the inner layer were changed as shown in Table 1.

[0116] <Comparative Examples 1 and 2> A sheet was produced in the same manner as in Example 1, except that the raw material blending composition of the resin composition for forming each layer and the lamination ratio of the outer layer and the inner layer were changed as shown in Table 1.

[0117] (Measurement and Evaluation Methods) <Arithmetic mean height of surface (Sa)> The arithmetic mean height (Sa) of the sheet was measured using a white light interferometer "Contour GTX" (manufactured by Bruker Japan) at an eyepiece magnification of 1.0x and an objective lens magnification of 5x, and was determined by measuring the arithmetic mean height and root mean square height of the surface.

[0118] <Total Haze · Internal Haze · External Haze> The haze of the sheets obtained in the examples and comparative examples was measured using a haze meter in accordance with JIS K7136:2000.

[0119] <Evaluation of image clarity> The image clarity of the sheets obtained in the Examples and Comparative Examples was evaluated in accordance with JIS K7374: 2007. The image clarity was measured using an ICM-1T (manufactured by Suga Test Instruments Co., Ltd.) using the following evaluation criteria. A: 5% or more B: Less than 5%

[0120] [Table 1]

[0121] The sheets (samples) obtained in the Examples had good image clarity, whereas the comparative examples had poor image clarity with an arithmetic mean height (Sa) of the surface of the outer layer (A) exceeding 700 nm. [Explanation of symbols]

[0122] 2. Inner layer 4 Outer layer 10 Sheets for press-through packaging.

Claims

1. The present invention provides a sheet-type laminated ... The inner layer (B) contains a high-density polyethylene resin and a low-density polyethylene resin, The sheet for press-through packaging, wherein the arithmetic mean height (Sa) of the surface of the outer layer (A) is 700 nm or less.

2. The press-through packaging sheet according to claim 1 , wherein the inner layer (B) further contains a polypropylene resin.

3. 2. The sheet for press-through packaging according to claim 1, wherein a content of the high-density polyethylene resin contained in the inner layer (B) is 60 mass % or less based on a total mass of the inner layer (B).

4. 2. The press-through packaging sheet according to claim 1, wherein the high-density polyethylene resin has a melt flow rate of 0.3 g / 10 min or more measured at a measurement temperature of 190° C. and a measurement load of 2.16 kg.

5. The sheet for press-through packaging according to claim 1 , wherein the inner layer (B) contains a tackifier resin.

6. The sheet for press-through packaging according to claim 1 , wherein the outer layer (A) comprises a tackifier resin.

7. The press-through packaging sheet according to claim 1, wherein the content of the low-density polyethylene contained in the inner layer (B) is 20 to 70 mass% based on the total mass of the inner layer (B).

8. The sheet for press-through packaging according to claim 1 , wherein the outer layer (A) has a thickness of 15 μm or more.

9. The water vapor transmission rate measured at a temperature of 40°C and a relative humidity of 90% in accordance with JIS K7129-2:2019 is 0.6 g / (m ２ The press-through packaging sheet according to claim 1, wherein the heat resistance is 24 hours or less.

10. 2. The press-through packaging sheet according to claim 1, having a total haze of 33% or less.

11. 2. The sheet for press-through packaging according to claim 1, having an external haze of 30% or less.

12. The press-through packaging sheet according to claim 1, wherein at least one selected from the high-density polyethylene resin and the low-density polyethylene resin is a biomass polyethylene.

13. The press-through packaging sheet according to claim 1, which is for pharmaceutical packaging.

14. A press-through package comprising the press-through package sheet according to any one of claims 1 to 13 in combination with a lid material.

15. The method includes co-extruding an outer layer (A)-forming resin composition containing a polypropylene resin as a main component and an inner layer (B)-forming resin composition containing a high-density polyethylene resin and a low-density polyethylene resin, and laminating the outer layer (A) and the inner layer (B), The method for producing a sheet for press-through packaging, wherein the arithmetic mean height (Sa) of the surface of the outer layer (A) after lamination is 700 nm or less.

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