Laminated sealant film, laminate, lid material, and packaging container

Abstract

The present invention addresses the problem of providing a laminated sealant film and a laminate having easy-peel properties and an antifogging function. The present invention also addresses the problem of providing a lid material and a packaging container having easy-open properties or easy-disassembly properties. The present invention relates to a laminated sealant film including a sealant film and an inorganic thin film layer provided on the sealant film, wherein the water contact angle of the inorganic thin film layer is 60° or less, and the heat seal strength when the inorganic thin film layer is heat-sealed in a state of facing the sealant film is 2 N / 15 mm to 10 N / 15 mm. The present invention also relates to a laminate including the laminated sealant film and a biaxially stretched polyolefin layer or a biaxially stretched polyester layer laminated on the sealant film. The present invention also relates to a lid material and a packaging container in which the laminate is used.

Description

Laminated sealant film, laminate, lid material, and packaging container

[0001] The present invention relates to a laminate sealant film, a laminate, a lid material, and a packaging container. The laminate sealant film may relate to a laminate sealant film used in the packaging fields of foods, medicines, industrial products, etc.

[0002] Containers made of molded plastic film or sheet are used as materials for packaging foods and the like. When using a plastic container, a plastic lid is often attached to the flange of the container after the contents have been filled into the container. The packaging is completed by attaching the lid to the container, and functions such as protecting the contents and preventing leakage are provided. Furthermore, by providing an anti-fogging function to the inner surface of the lid, it is possible to impart a function to prevent fogging due to water vapor from fruits and vegetables. As a method for attaching the lid to the container, the heat sealing method is commonly used from the viewpoints of simplicity and hygiene.

[0003] When a polyolefin resin is used for the sealant layer, the polyolefin resin has good heat sealing properties, so the sealed area is strongly bonded, which can make it difficult to open the container.

[0004] Therefore, several methods have been proposed to make it easier to open or dismantle paper containers. For example, Patent Document 1 discloses a technology in which a sealant layer has two or more easy-peel layers made of a polyethylene resin blended with an elastomer component, thereby stably causing cohesive failure of the sealed portion, thereby enabling the container to be easily opened or dismantled by hand.

[0005] However, the method described in Patent Document 1 requires changing the raw material of the base film itself, and a dedicated lot must be prepared, which poses the problem that it cannot accommodate a wide variety of small lots.

[0006] Patent Document 2 discloses a technique for adjusting adhesive strength by forming a vapor-deposited layer of a tin compound on the sealing surface of the opening of a glass container for hermetic packaging. Patent Document 3 also discloses a method for weakening the sealing strength of the top seal by applying a release agent to a specific portion of the sealant layer, thereby facilitating opening and disassembly.

[0007] However, the methods described in Patent Documents 2 and 3 require treatment at specific locations, which makes the process complicated and increases material and process costs, making the methods expensive and problematic in terms of practicality.

[0008] Japanese Patent No. 6171557 Japanese Utility Model Application Laid-Open No. 5-46775 Japanese Patent No. 3255075

[0009] The problem to be solved by the present invention is to provide a laminated sealant film and a laminate having easy-peel properties and anti-fogging function.The problem to be solved by the present invention is also to provide a lid material and a packaging container that are easy to open or dismantle.

[0010] The present inventors have found that providing an inorganic thin film layer on a sealant film can impart easy peelability and anti-fogging properties to the sealant film. For example, the present inventors have found that laminating an inorganic thin film layer on a sealant film can make the sealant film easy to open or dismantle, thereby providing a lid material that has easy peelability from a container and anti-fogging properties due to increased hydrophilicity.

[0011] The present invention has the following configuration [1]: [1] A laminated sealant film including a sealant film and an inorganic thin film layer provided on the sealant film, wherein the inorganic thin film layer has a water contact angle of 60° or less, and when the inorganic thin film layers are heat-sealed with the inorganic thin film layers facing each other, the heat seal strength is 2 N / 15 mm to 10 N / 15 mm.

[0012] The present invention preferably further comprises the following configurations [2] and subsequent items. [2] The laminate sealant film according to [1], wherein the inorganic thin film layer is an inorganic vapor deposition layer. [3] The laminate sealant film according to [1] or [2], wherein the inorganic thin film layer has a thickness of 50 nm or less. [4] The laminate sealant film according to any one of [1] to [3], wherein the inorganic thin film layer has a thickness of 1 nm or more or 3 nm or more. [5] The laminate sealant film according to any one of [1] to [4], wherein the inorganic thin film layer has a thickness of 5 nm or more or 10 nm or more. [6] The laminate sealant film according to any one of [1] to [5], wherein the inorganic thin film layer has a thickness of 40 nm or less. [7] The laminate sealant film according to any one of [1] to [6], wherein the inorganic thin film layer contains silicon oxide. [8] The laminate sealant film according to any one of [1] to [7], wherein the inorganic thin film layer contains aluminum oxide. [9] The laminate sealant film according to any one of [1] to [8], wherein the sealant film has thermoplastic properties.

[10] The laminate sealant film according to any one of [1] to [9], wherein the sealant film comprises a thermoplastic polymer.

[11] The laminate sealant film according to any one of [1] to

[10] , wherein the thermoplastic polymer comprises at least one of a polyethylene resin and a polypropylene resin.

[12] The laminate sealant film according to any one of [1] to

[11] , wherein the thickness of the sealant film is 20 μm or more or 40 μm or more.

[13] The laminate sealant film according to any one of [1] to

[12] , wherein the thickness of the sealant film is 250 μm or less or 100 μm or less.

[14] The laminate sealant film according to any one of [1] to

[13] , wherein the heat seal strength is 9 N / 15 mm or less or 8 N / 15 mm or less.

[15] The laminate sealant film according to any one of [1] to

[14] , wherein the heat seal strength is 4 N / 15 mm or more or 5 N / 15 mm or more.

[16] The laminate sealant film according to any one of [1] to

[15] , wherein the water contact angle is 55° or less or 50° or less.

[17] A laminate comprising the laminate sealant film according to any one of [1] to

[16] , and a biaxially oriented polyolefin layer or a biaxially oriented polyester layer laminated on the surface of the sealant film opposite to the surface on which the inorganic thin film layer is provided.

[18] A lid material using the laminate according to

[17] .

[19] A packaging container comprising the laminate according to

[17] or the lid material according to

[18] .

[0013] According to the present invention, it is possible to provide a laminated sealant film and a laminate having easy-peel properties and anti-fogging functions. According to the present invention, it is also possible to provide a lid material and a packaging container having easy-opening or easy-disassembly properties.

[0014] [Laminate Sealant Film] The laminate sealant film according to an embodiment of the present invention comprises a sealant film and an inorganic thin film layer disposed on the sealant film. Moreover, the inorganic thin film layer has a water contact angle of 60° or less. Furthermore, the laminate sealant film according to an embodiment of the present invention has a heat seal strength of 2 N / 15 mm to 10 N / 15 mm when heat-sealed with the inorganic thin film layers facing each other. Because the laminate sealant film comprises an inorganic thin film layer disposed on the sealant film, when a first adherend (e.g., a substrate film) is heat-sealed to a second adherend (e.g., a cup) using the laminate sealant film as a sealant, the first adherend can be peeled from the second adherend with a light force. Here, "light force" refers to a force smaller than the force required to peel the first adherend from the second adherend when the first adherend is heat-sealed to the second adherend using the sealant film itself as the sealant. In other words, because the laminate sealant film comprises an inorganic thin film layer disposed on the sealant film, the laminate sealant film can have easy-peel properties. Because the laminate sealant film includes an inorganic thin film layer, it is possible to prevent or reduce the formation of water droplets on the surface of the laminate sealant film (specifically, on the surface of the inorganic thin film layer), and therefore, it is possible to prevent or reduce excessive fogging of the laminate sealant film due to water droplets that may form on the surface of the laminate sealant film. In other words, because the laminate sealant film includes an inorganic thin film layer, the laminate sealant film can have an anti-fogging function. Moreover, because the water contact angle of the inorganic thin film layer is 60° or less, it is possible to further prevent or reduce the formation of water droplets on the surface of the inorganic thin film layer, and therefore, it is possible to further prevent or reduce excessive fogging of the laminate sealant film due to water droplets that may form on the surface of the inorganic thin film layer. In other words, because the water contact angle of the inorganic thin film layer is 60° or less, the laminate sealant film can have an even better anti-fogging function. Furthermore, since the heat seal strength is 10 N / 15 mm or less, when a first adherend (for example, a base film) is heat-sealed to a second adherend (for example, a cup) using the laminated sealant film as a sealant, the first adherend can be peeled off from the second adherend with even less force.That is, since the heat seal strength is 10 N / 15 mm or less, the laminated sealant film can be peeled off with even less force, that is, it can have even better easy-peel properties.

[0015] The laminate sealant film according to an embodiment of the present invention includes a first surface and a second surface opposite to the first surface. In other words, both surfaces of the laminate sealant film, i.e., a pair of outer surfaces, are composed of the first surface and the second surface. The first surface of the laminate sealant film according to an embodiment of the present invention is formed by an inorganic thin film layer. On the other hand, the second surface of the laminate sealant film may be formed by a sealant film. The first surface of the laminate sealant film may be referred to as the "easy peel surface" or "sealing surface."

[0016] Hereinafter, the sealant film will be described first, followed by the inorganic thin film layer and other layers laminated thereon.

[0017] [Sealant Film] The thermoplastic polymer forming the sealant film may be any polymer capable of sufficiently exhibiting sealant adhesive properties. Examples of suitable polymers include polyethylene resins such as HDPE (high-density polyethylene), LDPE (low-density polyethylene), and LLDPE (linear low-density polyethylene), polypropylene resin, ethylene-vinyl acetate copolymer, ethylene-α-olefin random copolymer, and ionomer resin. The sealant film is preferably an unstretched film. When subjected to moist heat treatment such as retort treatment, it is preferably formed by dry lamination using a polypropylene resin. The sealant film may be thermoplastic. A thickness of 20 to 250 μm is typically recommended, and 40 to 100 μm is desirable when used as a packaging material. The transparency of the sealant film is not particularly limited, but when used as a packaging material requiring transparency, a light transmittance of 50% or more is desirable.

[0018] The sealant film may be a single-layer film made of one type of plastic, or a laminated film made of two or more types of plastic films. When a laminated film is used, the type of each film, the number of layers, the lamination method, etc. are not particularly limited, and can be arbitrarily selected from known methods depending on the purpose. In addition, the sealant film may be subjected to surface treatment such as corona discharge treatment, glow discharge, flame treatment, surface roughening treatment, etc., as long as it does not impair the purpose of the present invention, and may also be subjected to known anchor coating treatment, printing, decoration, etc.

[0019] The sealant film can be formed using, for example, an inflation method or a T-die method, with the T-die method being preferred for its increased transparency and ease of drafting. While the inflation method uses air as the cooling medium, the T-die method uses a cooling roll, making it an advantageous production method for increasing the cooling rate of the unstretched sheet. Increasing the cooling rate not only suppresses crystallization of the unstretched sheet, but also provides the advantage of easily controlling the load applied to stretching in the subsequent process. For these reasons, molding using the T-die method is more preferable.

[0020] The lower limit of the temperature of the cooling roll when casting the molten raw resin to obtain a non-oriented sheet is not particularly limited, but is preferably 15°C, more preferably 20°C. If the temperature is lower than the above, condensation may occur on the cooling roll, resulting in insufficient adhesion between the unstretched sheet and the cooling roll, which may cause thickness defects. The upper limit of the cooling roll is not particularly limited, but is preferably 50°C, more preferably 40°C. If the temperature exceeds the above, the transparency of the polyolefin resin film may deteriorate.

[0021] The method for stretching the non-oriented sheet is not particularly limited, and for example, an inflation method or a roll stretching method can be used, but the roll stretching method is preferred because of the ease of controlling the orientation.

[0022] When adhering a sealant film to a base film, polyurethane resin, polyisocyanate resin, polyester resin, ether resin, etc. can be used to bond the sealant film to the base film. When performing a moist heat treatment such as retort treatment, it is preferable to use a reaction product of polyurethane resin and polyisocyanate resin as the adhesive. The amount of application varies depending on the material of the film to be adhered, but is preferably 1 to 20 g / m ２ is preferable, and more preferably 2 to 10 g / m ２ and more preferably 3 to 6 g / m ２ The adhesion temperature is set depending on the thickness of the sealant film and the thickness of the adhesive, but is preferably 50 to 120°C, more preferably 55 to 100°C, and even more preferably 60 to 80°C.

[0023] The sealant film may be made from biomass-derived or recycled materials.

[0024] [Inorganic thin film layer] The laminate sealant film according to an embodiment of the present invention has an inorganic thin film layer on a sealant film, and the surface of the inorganic thin film layer is an easy-peel surface. That is, the inorganic thin film layer includes an easy-peel surface. According to an embodiment of the present invention, by the simple process of providing an inorganic thin film layer on a sealant film, easy peeling can be achieved regardless of the type of sealant film (for example, regardless of the raw material of the sealant film), and therefore, it is possible to easily handle a wide variety of products in small lots.

[0025] The inorganic thin film layer is a thin film made of a metal or an inorganic oxide. There are no particular limitations on the material that forms the inorganic thin film layer as long as it can be made into a thin film. However, from the viewpoint of transparency, inorganic oxides such as silicon oxide (silica), aluminum oxide (alumina), and a mixture of silicon oxide and aluminum oxide are preferred. Here, silicon oxide refers to SiO or SiO ２ and various silicon oxides such as AlO and Al ２ O ３ and the like, or mixtures thereof.

[0026] The thickness of the inorganic thin film layer is usually 1 to 100 nm, preferably 3 to 80 nm, and more preferably 5 to 50 nm. If the thickness of the inorganic thin film layer is less than 1 nm, it may be difficult to obtain satisfactory easy-peel properties. On the other hand, if the thickness is excessively greater than 50 nm, the sealant film surface will be deformed by the heat load during vapor deposition, and the corresponding improvement in hydrophilicity will not be obtained, which is actually disadvantageous in terms of performance.

[0027] The method for forming the inorganic thin film layer is not particularly limited, and any known vapor deposition method may be appropriately employed, such as a physical vapor deposition method (PVD method) such as vacuum deposition, sputtering, or ion plating, or a chemical vapor deposition method (CVD method). A typical method for forming the inorganic thin film layer will be described below using a silicon oxide / aluminum oxide thin film as an example. For example, when vacuum deposition is employed, SiO ２ and Al ２ O ３ or a mixture of SiO ２ A mixture of Al and Al is preferably used. These deposition raw materials are typically particles, and the particle size is preferably large enough to prevent pressure changes during deposition, with a preferred particle diameter of 1 mm to 5 mm. Heating can be performed using methods such as resistance heating, high-frequency induction heating, electron beam heating, and laser heating. It is also possible to introduce oxygen, nitrogen, hydrogen, argon, carbon dioxide, water vapor, or other reactive gases as reactive gases, or to employ reactive deposition using ozone addition, ion-assisted deposition, or other methods. Furthermore, film formation conditions can be freely modified, such as by applying a bias to the deposition target (specifically, the sealant film to be deposited) or by heating or cooling the deposition target. The deposition materials, reactive gases, bias, heating, and cooling of the deposition target can be similarly modified when using sputtering or CVD.

[0028] The heat seal strength of the easy-peel surface of the sealant film on which the inorganic thin film layer is formed is preferably 3 to 10 N / 15 mm, more preferably 4 to 9 N / 15 mm, and even more preferably 5 to 8 N / 15 mm. If it is higher than 10 N / 15 mm, for example, a packaging container including a lid material made using the laminated sealant film will be difficult to open, and if it is lower than 3 N / 15 mm, the contents of the packaging container will easily spill.

[0029] The more hydrophilic the surface of the lid material that comes into contact with the contents, the better the visibility of the contents, and the water contact angle is preferably 60° or less, more preferably 55° or less, and even more preferably 50° or less.

[0030] [Laminate] The laminate according to the embodiment of the present invention may include a laminate sealant film according to the embodiment of the present invention and a base film. The base film is laminated on the surface opposite the easy-peel surface of the laminate sealant film, i.e., the second surface. Therefore, at least one of the two surfaces of the laminate according to the embodiment of the present invention may be formed by an inorganic thin film layer of the laminate sealant film. That is, in the laminate according to the embodiment of the present invention, at least one surface may be the easy-peel surface. In one example, one surface of the laminate may be formed by an inorganic thin film layer of the laminate sealant film, and the other surface may be formed by a base film. Since the laminate according to the embodiment of the present invention includes a laminate sealant film, when a container (for example, a cup) is heat-sealed with the laminate, or when a container (for example, a cup) is heat-sealed with a lid made using the laminate, a packaging container that is easy to open or disassemble can be formed. In other words, a packaging container that is easy to open or disassemble can be formed.

[0031] [Substrate Film] As described above, a laminate may be formed by laminating the sealant film according to the embodiment of the present invention with a substrate film. For example, the substrate film may be a stretched film obtained by melt-extruding a plastic and, if necessary, stretching it in the machine direction (MD direction) and / or the width direction (TD direction), cooling, and heat setting. From the viewpoint of obtaining mechanical strength, a biaxially stretched film stretched in the machine direction and the width direction is preferred. Examples of plastics include polyamides such as nylon 4.6, nylon 6, nylon 6.6, and nylon 12; polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene-2,6-naphthalate; polyolefins such as polyethylene, polypropylene, and polybutene; as well as polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, wholly aromatic polyamide, polyamideimide, polyimide, polyetherimide, polysulfone, polystyrene, and polylactic acid. The substrate film preferably includes at least one of a biaxially stretched polyolefin layer and a biaxially stretched polyester layer.

[0032] The substrate film may have any thickness depending on the desired purpose and application, such as mechanical strength and transparency. The thickness is not particularly limited, but is usually recommended to be 5 to 250 μm, and when used as a packaging material, it is desirable to have a thickness of 10 to 60 μm.

[0033] The substrate film may be a monolayer film made of one type of plastic, or a laminated film in which two or more types of plastic films are laminated. When a laminated film is used, the type of each film, the number of layers, the lamination method, etc. are not particularly limited, and can be arbitrarily selected from known methods depending on the purpose. Furthermore, the substrate film may be subjected to surface treatment such as corona discharge treatment, glow discharge, flame treatment, surface roughening treatment, etc., as long as it does not impair the purpose of the present invention, and may also be subjected to known anchor coating treatment, printing, decoration, etc.

[0034] [Other Layers] The laminate according to the embodiment of the present invention may have at least one or more printed layers, other plastic substrates and / or paper substrates laminated between the substrate film and the laminate sealant film or on the outer side thereof.

[0035] As the printing ink for forming the printing layer, aqueous and solvent-based resin-containing printing inks are preferably used. Examples of resins used in printing inks include acrylic resins, urethane resins, polyester resins, vinyl chloride resins, vinyl acetate copolymer resins, and mixtures thereof. The printing ink may contain known additives such as antistatic agents, light-blocking agents, ultraviolet absorbers, plasticizers, lubricants, fillers, colorants, stabilizers, lubricants, defoamers, crosslinking agents, anti-blocking agents, and antioxidants. The printing method for forming the printing layer is not particularly limited, and known printing methods such as offset printing, gravure printing, and screen printing can be used. To dry the solvent after printing, known drying methods such as hot air drying, heat roll drying, and infrared drying can be used.

[0036] On the other hand, from the viewpoint of obtaining sufficient rigidity and strength of the laminate, other plastic substrates and paper substrates are preferably used, such as paper, polyester resin, polyamide resin, and biodegradable resin. In addition, in order to obtain a film with excellent mechanical strength, stretched films such as biaxially stretched polyester film and biaxially stretched nylon film are preferred.

[0037] As described above, the laminate sealant film according to the embodiment of the present invention has excellent easy peel properties and hydrophilicity, and is easy to produce and economical.

[0038] [Lid material] The lid material according to the embodiment of the present invention is produced using the laminate according to the embodiment of the present invention. The lid material according to the embodiment of the present invention includes the laminate according to the embodiment of the present invention. At least one of the two surfaces of the lid material according to the embodiment of the present invention can be formed by an inorganic thin film layer of the laminate (i.e., the inorganic thin film layer of the laminate sealant film). That is, in the lid material according to the embodiment of the present invention, at least one surface can be an easy-peel surface.

[0039] [Packaging Container] A packaging container according to an embodiment of the present invention includes at least one of a laminate according to an embodiment of the present invention and a lid material according to an embodiment of the present invention. The packaging container according to an embodiment of the present invention may include a container, and at least one of a laminate and a lid material heat-sealed to the container.

[0040] The laminate sealant film, laminate, lid material, and packaging container according to the embodiments of the present invention can be widely used for packaging various foods, pharmaceuticals, industrial products, etc.

[0041] In the above-described embodiment, the laminate sealant film is mainly used to produce a lid material. However, the use of the laminate sealant film is not limited to this. The laminate sealant film according to the embodiment of the present invention may be used to produce, for example, a pouch.

[0042] The present invention will be explained in more detail below by way of examples, but the present invention is not limited to the following examples and can be practiced by making appropriate modifications within the scope of the above and below-described aims, and all such modifications are included in the technical scope of the present invention.

[0043] The processing methods and evaluation and property measurement methods used in each of the examples and comparative examples are as follows.

[0044] (1) Thickness Measurement Conditions for Inorganic Thin Film Layer The thickness of the inorganic thin film layer was measured using a wavelength dispersive small fluorescent X-ray analyzer (Rigaku Corporation's "Supermini 200"). A sample with a known thickness was measured in advance, the amount of fluorescent X-ray emitted from the sample was determined, and the thickness of the inorganic thin film layer was calculated from a calibration curve of the thickness and the fluorescent X-ray intensity.

[0045] (2) Seal Strength Measurement Conditions Heat seal strength was measured in accordance with JIS Z1707. The specific procedure is briefly described below. The sealing conditions for the heat sealer, specifically the hot plate sealer, were an upper bar temperature of 160°C, a lower bar temperature of 100°C, a pressure of 0.2 MPa, and a time of 2 seconds. A measurement sample measuring 15 mm wide x 200 mm long was cut out from a laminated sealant film (hereinafter sometimes referred to as a "laminated film") in which an inorganic thin film layer was formed on a sealant film, and the surfaces of the inorganic thin film layers (easy-peel surfaces) were pressure-bonded together. Peel strength was measured at a tensile speed of 200 mm / min using a Shimadzu "Universal Tensile Tester DSS-100." Peel strength was measured as the strength per 15 mm (N / 15 mm). The average peel strength determined for three test pieces was taken as the heat seal strength.

[0046] (3) Contact angle measurement conditions: A contact angle meter DSA100S manufactured by KRUSS was used. 1 μL of water was dropped onto the inorganic thin film layer side seal surface (easy peel surface) under an atmosphere of 23° C. and 50% RH, and the contact angle was measured. Measurements were made at 10 points, and the average value was calculated.

[0047] (4) Anti-Fog Property Evaluation A 500 mL beaker was filled with water and heated to 52°C. A film (for example, a laminated film in Examples 1 to 8 and Comparative Example 3) was placed over the beaker so that the surface to be evaluated (for example, the easy-peel surface in Examples 1 to 8 and Comparative Example 3) faced the warm water side, and the beaker was then covered with a lid. The film was then left to stand for 30 minutes in an atmosphere of 5°C, removed from the beaker at room temperature, and visually evaluated on a three-point scale (good, fair, or bad). A film with 0 to 20% of the surface area covered by the film and the remainder forming a water film was evaluated as good, a film with 30 to 70% of the surface area covered by the film was evaluated as fair, and a film with 80 to 100% of the surface area covered by the film was evaluated as bad.

[0048] (5) Preparation of Laminates Various substrates were laminated onto the sealant film side of the laminate film in which an inorganic thin film layer was applied to the sealant film. For bonding, a dry lamination adhesive was used, obtained by mixing 28.9% by mass of the base agent ("TM569" manufactured by Toyo-Morton Co., Ltd.), 4.00% by mass of the curing agent ("CAT10L" manufactured by Toyo-Morton Co., Ltd.), and 67.1% by mass of ethyl acetate. A laminate was obtained by aging at 40 ° C for 4 days. The thickness of the adhesive layer formed with the two-component curing adhesive after drying was approximately 4 μm.

[0049] (6) Evaluation method for easy peeling properties Using a polyolefin cup, the cup and the inorganic thin film layer of the obtained laminate were heat-sealed in a state where they faced each other. For heat sealing, a "PACK SEALER" manufactured by Eishin Pack Kogyo Co., Ltd. was used, and the sealing conditions were a bar temperature of 180°C and a time of 2 seconds. The ease of peeling when peeling the obtained packaging container by hand was evaluated on a three-point scale (good, fair, and bad). Easy to peel was evaluated as good, a mixture of easy and difficult to peel parts was evaluated as fair, and difficult to peel was evaluated as bad.

[0050] The films and deposition materials used in each of the examples and comparative examples are described below.

[0051] Example 1: A 40 μm-thick unstretched polyethylene film (LLDPE) was used, and the roll was set in an electron gun-heated vapor deposition device with a roll-to-roll film running system so that vapor deposition would occur on the sealing surface, to produce an inorganic thin film layer. SiOx was used as the vapor deposition source. As a pre-deposition treatment, plasma treatment was performed in a vacuum system. SiOx was evaporated by electron gun heating, and SiOx vapor deposition was performed to obtain a laminate film. The obtained laminate film was measured for the thickness of the inorganic thin film layer, the contact angle of the inorganic thin film layer surface, the heat seal strength between the inorganic thin film layers, and the anti-fogging properties. Subsequently, a laminate was produced using a 12 μm-thick biaxially oriented polyethylene terephthalate film as a substrate, and a sensory evaluation of easy-peel properties was performed.

[0052] Example 2 A laminate film and a laminate were produced and evaluated in the same manner as in Example 1, except that the output during heating of the electron gun was changed and the film thickness of the inorganic thin film layer was changed.

[0053] Examples 3 and 4 Laminated films and laminates were produced and evaluated in the same manner as in Example 1, except that the deposition source was changed as shown in Table 1 and the output during electron gun heating was changed to give film thicknesses as shown in Table 1.

[0054] Examples 5 to 7 Laminated films and laminates were produced and evaluated in the same manner as in Example 1, except that the sealant film forming the inorganic vapor deposition layer was changed to a non-oriented polypropylene film (CPP) having a thickness of 30 μm, and the vapor deposition source and the film thickness of the inorganic thin film layer were changed as shown in Table 1.

[0055] Example 8 A laminate film and a laminate were produced and evaluated in the same manner as in Example 1, except that the base film was changed to a biaxially oriented polypropylene film.

[0056] Comparative Example 1 A laminate film and a laminate were prepared and evaluated in the same manner as in Example 1, except that no inorganic thin film layer was formed and only an unstretched polyethylene film was used. As a result, it was found that the heat seal strength was high, the laminate was difficult to peel, the contact angle of the sealed surface was high, and the laminate was hydrophobic, making it impossible to impart anti-fogging function.

[0057] Comparative Example 2 A laminate film and a laminate were produced and evaluated in the same manner as in Comparative Example 1, except that only a non-oriented polypropylene film (CPP) was used as the sealant film.

[0058] Comparative Example 3: Except for changing the output when heating the electron gun and making the film thickness of the inorganic thin film layer very thick, a laminate film and a laminate were produced and evaluated in the same manner as in Example 1. As a result, it was found that the surface of the laminate film was altered by the heat load during the formation of the inorganic thin film layer, the contact angle was high, it became hydrophobic, and anti-fogging function could not be imparted.

[0059]

[0060] INDUSTRIAL APPLICABILITY The present invention has industrial applicability because it can provide a laminate sealant film, a laminate, a lid material, or a packaging container.

Claims

1. A laminated sealant film comprising a sealant film and an inorganic thin film layer provided on the sealant film, wherein the inorganic thin film layer has a water contact angle of 60° or less, and when the inorganic thin film layers are heat sealed while facing each other, the heat seal strength is 2 N / 15 mm to 10 N / 15 mm.

2. The laminate sealant film according to claim 1, wherein the inorganic thin film layer is an inorganic vapor deposition layer.

3. The laminate sealant film according to claim 1, wherein the inorganic thin film layer has a thickness of 50 nm or less.

4. A laminate comprising the laminate sealant film according to claim 1 and a biaxially oriented polyolefin layer or a biaxially oriented polyester layer laminated on the surface of said sealant film opposite to the surface on which said inorganic thin film layer is provided.

5. A lid material using the laminate according to claim 4.

6. A packaging container comprising the laminate according to claim 4 or the lid material according to claim 5.

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