JP5770349B2 - Laminated body and method for producing the same - Google Patents

Description

  The present invention relates to a laminate, and more specifically, a laminate film provided with a thermoplastic resin film, an aluminum oxide thin film layer and a gas barrier protective layer in this order and a polyolefin resin film are bonded without using an adhesive. The present invention relates to a laminate and a manufacturing method thereof.

  A package in which a film or the like is processed into a bag shape is used. In such a package, a multifunctional film in which various materials are laminated is used as a film to be used in order to develop a desired function depending on the contents to be filled. For example, in order to prevent deterioration of the contents due to ultraviolet rays, etc., a film having an ultraviolet absorption function is used, or in order to prevent the contents from being altered by oxygen, a gas-impermeable film or oxygen absorption is used. A film having a function is used.

  The package is generally performed by processing a long film, but in order to process it into a bag shape, the end portions of the films are overlapped and bonded. As a method of bonding films, a laminate resin (adhesive) is applied to the ends of the films to be bonded, and the films are pressed and sealed, or the two films are overlapped and heated at the ends. In general, a so-called heat sealing process is performed to add and fuse.

  Since heat sealing does not use a laminate resin or the like when bonding the films, the films can be bonded easily and simply. However, the heat sealing process is a method in which the films are partially melted or semi-melted, and the films are bonded to each other, so that different films, for example, a polyolefin film and a polyester film are bonded to each other. It cannot be bonded by heat sealing. In addition, in heat seal processing, it is necessary to use a film made of a resin that can be fused at a relatively low temperature. Therefore, a multilayer film in which a heat sealable resin layer such as polyolefin resin is provided on the outermost surface layer is used. (For example, JP-A-55-107428).

On the other hand, when films are bonded together by laminating, the components of the laminating resin are appropriately selected according to the type of film to be used (type of resin).
For example, when processing into a bag shape by bonding a polyester film and a nylon film, a urethane adhesive has been used (for example, JP-A-52-82594).

  However, in the case of a package made by bonding films made of different materials through a laminate resin, the laminate resin component may gradually elute or volatilize in the package, and the contents may be altered. In the medical field where cleanliness is important, contamination of the contents by the laminate resin may be a problem. In addition, the laminate resin itself may deteriorate due to long-term use of the package, and particularly in exterior applications that are used outdoors, the weather resistance of the laminated package may become a problem. In addition, in the laminating technique using an adhesive, since a resin component diluted in a solvent is generally applied, the solvent remains after laminating to form a final product such as a package. There was a case.

  By the way, surface modification of a material using radiation or an electron beam has been conventionally performed. For example, Japanese Patent Application Laid-Open No. 2003-119293 (Patent Document 3) proposes that a crosslinked composite fluororesin can be obtained by irradiating the fluororesin with radiation. In Journal of Photopolymer Science and Technology Vol.19, No. 1 (2006), pp123-127 (Non-patent Document 1), a polytetrafluoroethylene film and a polyimide film are laminated and an electron beam ( In the following, it has been proposed to bond each other by irradiating EB. In Material Transactions Vol.50, No.7 (2009), pp1859-1863 (Non-patent Document 2), the surface of the polycarbonate resin is covered with a nylon film, and an electron beam (hereinafter abbreviated as EB) may be applied from above. A technique for adhering a nylon film to a polycarbonate resin surface has been proposed. Furthermore, the Journal of the Japan Institute of Metals, Vol. 72, No. 7 (2008), pp 526-531 (Non-patent Document 3) can be bonded to each other by irradiating EB from a nylon film placed on silicone rubber. Is described.

JP-A-55-107428 JP 52-82594 A JP 2003-119293 A

Journal of Photopolymer Science and Technology Vol.19, No. 1 (2006), pp123-127 Material Transactions Vol.50, No. 7 (2009), pp1859-1863 Journal of the Japan Institute of Metals, Vol. 72, No. 7 (2008), pp 526-531

  The present inventors have now found that even when films made of different materials are bonded to each other, the films can be firmly bonded to each other without using a laminate resin or the like by irradiating the films with an electron beam. . And even if it is a laminate that has been bonded to each other with an adhesive, such as a laminate of a laminated film including a gas barrier protective layer and a polyethylene film, an adhesive is used according to electron beam irradiation. Even if it did not do, the knowledge that a covalent bond or a hydrogen bond was formed between the atom by the side of a lamination | stacking film and the atom by the side of a polyethylene film, and mutually adhered was acquired. The present invention is based on this finding.

  Therefore, an object of the present invention is a laminate in which a laminate film including a gas barrier protective layer and a polyolefin film are bonded without using an adhesive, and it has a weather resistance without leaching of foreign matters or residual solvents. Is to provide an excellent laminate.

A laminate according to the present invention comprises a thermoplastic resin film, an aluminum oxide thin film layer provided on at least one surface of the thermoplastic resin film, and a gas barrier protective layer provided on the aluminum oxide thin film layer. And the polyolefin resin film is a laminate in which the gas barrier protective layer and the polyolefin resin film are laminated so as to face each other,
The gas barrier protective layer comprises a film obtained by applying a solution containing at least a water-soluble polymer having a hydroxyl group and alkoxysilane,
In at least a part of the gas barrier protective layer and the polyolefin resin film, a covalent bond is formed between a silicon atom in the gas barrier protective layer and a carbon atom in the polyolefin resin film, and the gas barrier property The protective layer and the polyolefin resin film are bonded without using an adhesive.

  Further, as an aspect of the present invention, an oxygen atom or a hydroxyl group is covalently bonded to a carbon atom in the polyolefin resin film, and an oxygen atom and / or a hydroxyl group in the gas barrier protective layer and oxygen in the polyolefin resin film It is preferable that a hydrogen bond is formed between the atom or the hydroxyl group.

Further, as an aspect of the present invention, the alkoxysilane is represented by the following general formula:
R _1n Si (OR ₂ ) _m
(In the formula, R ₁ and R ₂ each independently represent an organic group having 1 to 8 carbon atoms, n represents an integer of 0 or more, m represents an integer of 1 or more, and n + m represents an Si atom. Represents the value.)
It is preferable to be represented by

  In one embodiment of the present invention, the water-soluble polymer having a hydroxyl group is selected from the group consisting of polyvinyl alcohol, polyvinyl pyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, sodium alginate, and an ethylene-vinyl alcohol copolymer. It is preferably a seed or a mixture of two or more.

  Moreover, as an aspect of the present invention, the polyolefin resin film is preferably a polyethylene film.

  Moreover, as an aspect of the present invention, the thermoplastic resin film is preferably a polyethylene terephthalate film.

Moreover, the production method as another aspect of the present invention is a method for producing a laminate in which a laminate film and a polyolefin resin film are laminated,
A gas barrier protective layer surface of a laminated film comprising a thermoplastic resin film, an aluminum oxide thin film layer provided on at least one surface of the thermoplastic resin film, and a gas barrier protective layer provided on the aluminum oxide thin film layer; and And / or irradiating at least one surface of the polyolefin resin film with an electron beam, and bonding the gas barrier protective layer surface irradiated with the electron beam of the laminated film and the polyolefin resin film surface. It is a feature.

  Moreover, as an aspect of the present invention, it is preferable to perform electron beam irradiation before and / or after the laminated film and the polyolefin resin film are overlaid.

  As another aspect of the present invention, it is preferable that an acceleration voltage of the electron beam irradiation is in a range of 40 to 120 kV.

  According to the present invention, in a laminated film comprising a thermoplastic resin film, an aluminum oxide thin film layer provided on at least one surface of the thermoplastic resin film, and a gas barrier protective layer provided on the aluminum oxide thin film layer Since a covalent bond and / or a hydrogen bond is formed between the atoms in the polyolefin resin film and the atoms in the polyolefin resin film, the laminated film and the polyolefin resin film are firmly bonded even if they are not bonded via an adhesive. A bonded laminate is obtained. As a result, it is possible to realize a laminate having excellent weather resistance without alien substances or residual solvent leaching.

It is the schematic sectional drawing which showed one Embodiment of the laminated body of this invention. It is the schematic cross section which expanded the interface (adhesion surface) of the laminated body. It is the schematic diagram which showed one Embodiment of the manufacturing method of the laminated body by this invention. It is the schematic schematic diagram which expanded a part of manufacturing process. It is the schematic diagram which showed another embodiment of the manufacturing method of the laminated body by this invention. It is the schematic diagram which showed another embodiment of the manufacturing method of the laminated body by this invention. It is the schematic diagram which showed another embodiment of the manufacturing method of the laminated body by this invention. The XPS spectrum of the gas barrier protective layer surface of the laminated film before electron irradiation. XPS spectrum of polyethylene film before electron irradiation. The XPS spectrum of the gas barrier protective layer surface of the laminated film after electron irradiation. XPS spectrum of polyethylene film after electron irradiation.

  Hereinafter, the laminated body by this invention is demonstrated, referring drawings. As shown in FIG. 1, the laminate 1 according to the present invention has a structure in which a laminate film 20 and a polyolefin resin film 10 are laminated without using an adhesive. The laminated film 20 includes a thermoplastic resin film 21, an aluminum oxide thin film layer 22 provided on at least one surface of the thermoplastic resin film 20, and a gas barrier protective layer 23 provided on the aluminum oxide thin film layer 22.

  The gas barrier protective layer 23 corresponding to the adhesion surface of the laminated film 20 to the polyolefin resin film 10 is a coating obtained by applying a solution containing at least a water-soluble polymer having a hydroxyl group and alkoxysilane. In the present invention, at least part of the adhesive surface, a covalent bond is formed between the silicon atom in the gas barrier protective layer and the carbon atom in the polyolefin resin film, so that the laminated film and the polyolefin resin film are Are firmly bonded. Usually, the surface of the gas barrier protective layer obtained by applying a solution containing a water-soluble polymer having a hydroxyl group such as polyvinyl alcohol and alkoxysilane is hydrophilic, while the surface of the polyolefin resin film is hydrophobic. Therefore, normally, the two cannot be bonded unless an adhesive is used. In the present invention, as will be described later, the surface of the gas barrier protective layer and / or the polyolefin resin film is irradiated with an electron beam to generate radicals. A covalent bond is formed between the silicon atom and the carbon atom in the polyolefin resin film 10, and the laminated film 20 and the polyolefin resin film 10 are firmly bonded without using an adhesive. Generation of radicals by electron beam irradiation can be confirmed by identifying free radical species present in the film after electron beam irradiation using an electron spin resonance apparatus (hereinafter also referred to as ESR). it can.

  The fact that a covalent bond is formed between atoms between the laminated film and the polyolefin resin film means that an X-ray photoelectron analyzer (hereinafter also referred to as XPS) or a Fourier transform infrared spectrometer (hereinafter also referred to as FTIR). )). For example, before bonding the laminated film and the polyolefin resin film, by measuring the surface state of each film by XPS, it is possible to confirm what atoms are present on the surface of each film before bonding. Then, both films were bonded by electron beam irradiation to form a laminate, and the laminate was forcibly separated to separate it into a laminate film and a polyolefin resin film, and again, the surface state of each film was measured by XPS. Check what atoms are present on the surface of each film. As a result, by confirming that there are atoms derived from the polyolefin resin film on the laminated film side or atoms derived from the laminated film on the polyolefin resin film side, is a covalent bond formed between both films? You can check if. Moreover, you may confirm whether supply bonds, such as a C-O bond, a C = O bond, and a Si-C bond, exist on the surface of the polyolefin resin film after peeling using FTIR.

  Moreover, as shown in FIG. 2, the laminate in which the laminate film 20 and the polyolefin resin film 10 are bonded by electron beam irradiation has oxygen atoms or hydroxyl groups covalently bonded to carbon atoms in the polyolefin resin film, and thus has a gas barrier property. Hydrogen bonds are formed between oxygen atoms and / or hydroxyl groups in the protective layer 23 and oxygen atoms or hydroxyl groups in the polyolefin resin film 10. Since the laminate according to the present invention is bonded to the laminate film and the polyolefin resin film by such a hydrogen bond or the above-described covalent bond, the laminate does not cause peeling even if no adhesive is used. can do. The presence of hydrogen bonds can be confirmed by immersing the laminate in water or an alcohol solution and confirming the presence or absence of peeling. When both films are bonded only by hydrogen bonds, when the laminate is immersed in water or an alcohol solution, hydrogen bonds formed between the atoms of both films are broken, and hydrogen atoms or oxygen of water or alcohol Since the atoms and hydrogen bonds are reformed, the adhesive force is lost and the two films are peeled off.

Hereinafter, the laminated film and polyolefin resin film which comprise the laminated body by this invention are demonstrated.
<Laminated film>
As shown in FIG. 1, the laminated film 20 includes a thermoplastic resin film 21, an aluminum oxide thin film layer 22 provided on at least one surface of the thermoplastic resin film 21, and a gas barrier protection provided on the aluminum oxide thin film layer 22. Layer 23 is included. Although not shown, the laminated film 20 may be one in which the aluminum oxide thin film 22 and the gas barrier protective layer 23 are provided not only on one surface of the thermoplastic resin film 21 but also on both surfaces.

  In the laminated film 20 used for the laminated body according to the present invention, the aluminum oxide thin film 21 and the gas barrier protective film 23 form, for example, a chemical bond, a hydrogen bond, or a coordinate bond by a hydrolysis / co-condensation reaction. Adhesiveness between the aluminum oxide thin film 22 and the gas barrier protective layer 23 is improved, and a better gas barrier effect can be exhibited by the synergistic effect of the two layers.

  As the thermoplastic resin film, any plastic film capable of supporting an aluminum oxide thin film can be used. For example, polyolefin resin such as polyethylene, polypropylene, polybutene, (meth) acrylic resin, Polyvinyl chloride resin, polystyrene resin, polyvinylidene chloride resin, saponified ethylene-vinyl acetate copolymer, polyvinyl alcohol, polycarbonate resin, fluorine resin, polyvinyl acetate resin, acetal resin, polyethylene terephthalate ( Various resins such as polyester resins such as PET), polyethylene naphthalate (PEN), and polybutylene naphthalate (PBN), polyamide resins such as nylon 6 and nylon 66, and the like can be used. Among these, polyethylene terephthalate (PET) is preferable, and transparent one is more preferable.

  The thermoplastic resin film may be uniaxially or biaxially stretched, and the thickness is preferably about 10 to 200 μm, particularly about 10 to 100 μm. If necessary, the surface may be coated with an anchor coating agent or the like to be subjected to a surface smoothing treatment or the like.

The aluminum oxide thin film layer was formed by forming an aluminum oxide thin film represented by the general formula: AlO _x (wherein x represents a number of 0.5 to 1.5) on the surface of the thermoplastic resin film. Is. As the aluminum oxide thin film represented by the above general formula, an aluminum oxide thin film in which the value of x increases in the depth direction from the film surface toward the inner surface can also be used. In the above, as the value of x, basically, x = 0.5 or more can be used. However, when x = less than 1.0, it is easy to be colored, and transparency, microwave oven Since it is inferior in suitability, it is preferable to use x = 1.0 or more. As the upper limit, those up to x = 1.5 in which aluminum and oxygen are completely oxidized can be used.

  The thickness of the aluminum oxide thin film is preferably selected and formed, for example, within a range of about 10 to 3000 mm, particularly about 60 to 1000 mm. The aluminum oxide thin film may be crystalline or amorphous.

  In the present invention, when the total light transmittance of the thermoplastic resin film constituting the laminated film is 100%, it is desirable to deposit aluminum oxide so that the total light transmittance after deposition is less than 90%, It is particularly preferable to deposit aluminum oxide so that the total light transmittance after deposition is 85% or more and less than 90% when the total light transmittance of the base film is 100%. When the total light transmittance after vapor deposition is 90% or more after vapor deposition, although the transparency is sufficient, the gas barrier property, particularly the gas barrier property against water vapor, may not be sufficiently high. Moreover, when the total light transmittance after vapor deposition is less than 85%, although the gas barrier property is excellent, the final transparency may not reach the total light transmittance of the thermoplastic resin film.

  Next, a method for forming an aluminum oxide thin film on a thermoplastic resin film will be described. As a method of forming an aluminum oxide thin film, for example, a physical vapor deposition method (Physical Vapor Deposition method, PVD method) such as a vacuum deposition method, a sputtering method, an ion plating method, or a plasma chemical vapor deposition method, Examples thereof include a chemical vapor deposition method (chemical vapor deposition method, CVD method) such as a thermal chemical vapor deposition method and a photochemical vapor deposition method. In addition, when manufacturing the film which consists of a transparent laminated body used for the packaging material, a vacuum vapor deposition method is mainly used and a plasma chemical vapor deposition method is also used partially.

In addition, for example, a composite film composed of two or more vapor-deposited films of different kinds of inorganic oxides can be formed by using both physical vapor deposition and chemical vapor deposition. In the case of forming an aluminum oxide thin film in which the value of x increases in the depth direction from the film surface to the inner surface, the aluminum oxide thin film is disclosed in Japanese Patent Application Laid-Open No. 10-226011 by the present applicant. It can be manufactured by the method. The degree of vacuum deposition chamber, before ^introduction of oxygen 10 ^-2 to 10 -8 mbar approximately, in ^particular, is preferably about 10 ^-3 to 10 -7 mbar, in the post-oxygen ^{introduction,} 10 -1 to 10 ^{- About 6} mbar, especially about 10 ⁻² to 10 ⁻⁵ mbar is preferable. The amount of oxygen introduced varies depending on the size of the vapor deposition machine. For the oxygen to be introduced, an inert gas such as argon gas, helium gas, nitrogen gas or the like may be used as a carrier gas within a range where there is no problem. As a conveyance speed of the thermoplastic resin film used as a base material, about 10-800 m / min, especially about 50-600 m / min are preferable.

  In the present invention, the surface of the aluminum oxide thin film formed as described above may be subjected to oxygen plasma treatment. The amount of oxygen introduced for the oxygen plasma treatment varies depending on the size of the vapor deposition apparatus and the like, but is usually about 50 sccm to 2000 sccm, and particularly preferably about 300 sccm to 800 sccm. Here, sccm means the average amount of oxygen introduced (cc) per minute in the standard state (STP: 0 ° C., 1 atm). For the oxygen to be introduced, an inert gas such as argon gas, helium gas, nitrogen gas or the like may be used as a carrier gas within a range where there is no problem. The method for forming the aluminum oxide thin film on the thermoplastic resin film and the method for subjecting the surface of the aluminum oxide thin film to oxygen plasma treatment as desired have been described above. However, these are examples, and the present invention is not limited to these methods. It is not limited to what was obtained.

  Next, the gas barrier protective layer provided on the aluminum oxide thin film formed as described above will be described. The gas barrier protective layer can be formed by coating with a solution containing at least a water-soluble polymer having a hydroxyl group and alkoxysilane. Examples of the water-soluble polymer having at least a hydroxyl group include polyvinyl alcohol, polyvinyl pyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, sodium alginate, ethylene-vinyl alcohol copolymer, and the like. Polyvinyl alcohol is preferred. These resins may be commercially available. For example, as an ethylene / vinyl alcohol copolymer, Kuraray Co., Ltd., Eval EP-F101 (ethylene content: 32 mol%), Nippon Synthetic Chemical Industry Co., Ltd., Soarnol D2908 (ethylene content; 29 mol%) and the like can be used. Also, as polyvinyl alcohol, RS-110 (degree of saponification = 99%, degree of polymerization = 1,000) manufactured by Kuraray Co., Ltd., Kuraray Poval LM-20SO (degree of saponification = 40%) manufactured by the same company. Degree of polymerization = 2,000), Gohsenol NM-14 (degree of saponification = 99%, degree of polymerization = 1,400) manufactured by Nippon Synthetic Chemical Industry Co., Ltd. can be used.

As alkoxysilane, the general formula:
R _1n Si (OR ₂ ) _m
(In the formula, R ₁ and R ₂ each independently represent an organic group having 1 to 8 carbon atoms, n represents an integer of 0 or more, m represents an integer of 1 or more, and n + m represents an Si atom. Can be suitably used. In the above formula, specific examples of the organic group represented by R ₁ include, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group. , T-butyl group, n-hexyl group, n-octyl group, and other alkyl groups. Specific examples of the alkoxysilane include, for example, tetramethoxysilane: Si (OCH ₃ ) ₄ , tetraethoxysilane: Si (OC ₂ H ₅ ) ₄ , tetrapropoxysilane: Si (OC ₃ H ₇ ) ₄ , tetrabutoxysilane. : Si (OC ₄ H ₉ ) ₄ or the like can be used.

  By mixing the above-mentioned water-soluble polymer and alkoxysilane, and further applying a solution to which a sol-gel method catalyst, water, and an organic solvent are added as desired, onto the surface of the aluminum oxide thin film, A gas barrier protective layer can be formed. Moreover, in this invention, the composite polymer layer which laminated | stacked two or more said coating films on the aluminum oxide thin film can also be formed.

  Moreover, in this invention, a silane coupling agent can be added to said coating liquid for gas barrier property protective layer formation, and the gas barrier property protective layer obtained by this is especially preferable. As the silane coupling agent, known organic reactive group-containing organoalkoxysilanes can be used. In particular, an organoalkoxysilane having an epoxy group is suitable, for example, γ-glycidoxypropyltrimethoxy. Silane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, or the like can be used. The above silane coupling agents may be used alone or in combination of two or more. In this invention, the usage-amount of the above silane coupling agents can be used within the range of about 1-20 mass parts with respect to 100 mass parts of said alkoxysilane.

  As a coating method of the coating solution for forming the gas barrier protective layer, conventionally known means such as roll coating such as gravure roll coater, spray coating, spin coating, dipping, brush, bar code, applicator and the like are used. . Although the thickness of the coating film varies depending on the type of the coating solution, the thickness after drying may be in the range of about 0.01 to 100 μm. However, if the thickness is 50 μm or more, cracks are likely to occur in the film. It is preferable to be set to ˜50 μm.

  As a sol-gel method catalyst for polycondensation with a coating solution, a tertiary amine that is substantially insoluble in water and soluble in an organic solvent is used. Specifically, for example, N, N-dimethylbenzylamine, tripropylamine, tributylamine, tripentylamine and the like can be used. In particular, N, N-dimethylbenzylamine is suitable, and 0.01 to 1.0 part by weight, particularly about 0.03 part by weight is used per 100 parts by weight of the total amount of alkoxysilane and silane coupling agent. It is preferable to do.

Moreover, an acid can also be used as a catalyst of a sol-gel method, for example, mineral acids, such as a sulfuric acid, hydrochloric acid, nitric acid, organic acids, such as an acetic acid and tartaric acid, and others can be used.
The amount of the acid used is preferably about 0.001 to 0.05 mol, particularly about 0.01 mol, relative to the total molar amount of alkoxysilane and the alkoxysilane content (for example, silicate moiety) of the silane coupling agent.

  Water contained in the coating solution is added in a proportion of 0.1 to 100 mol, preferably 0.8 to 2 mol, per 1 mol of the total molar amount of the solution alkoxide. Moreover, it is preferable that the polyvinyl alcohol and the ethylene-vinyl alcohol copolymer contained in the coating liquid for forming a gas barrier protective layer are in a state dissolved in a coating liquid containing the above-described alkoxysilane, silane coupling agent, etc. Therefore, an organic solvent may be appropriately selected and added. For example, as the organic solvent, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butanol and the like can be used.

<Polyolefin resin film>
As the polyolefin resin film constituting the laminate of the present invention, a simple substance such as low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene, or a mixture of polypropylene and low density polyethylene, A film made of a mixture of polypropylene and high-density polyethylene can be used. Moreover, although the thickness of a film can be suitably determined according to a use application, it is about 20-300 micrometers in general.

  Various conventionally known additives such as a light stabilizer, an ultraviolet absorber, an antioxidant, a filler, a lubricant, and the like can be appropriately added to the polyolefin resin film as necessary. Conventionally known light stabilizers and ultraviolet absorbers can be used, such as phenolic, phosphorous, and hindered amine light absorbers, and benzotriazole, benzophenone, and salicylic acid ester ultraviolet absorbers. Can be used.

  The laminated body in which the laminated film and the polyolefin resin film are bonded together as described above does not exude foreign matter or residual solvent even when the laminated body is used, and has excellent weather resistance. It can be suitably used for a packaging body used in the field, for example, a packaging body for filling and packaging a syringe packaging bag or a powder or granular medicine.

<Method for producing laminate>
Next, a method for producing the laminate as described above will be described with reference to the drawings. First, the laminated film 20 and the polyolefin resin film 10 described above are prepared (FIG. 3 (1)), and one or both of the two films are irradiated with an electron beam (FIG. 3 (2)). )). As a result, as shown in FIG. 3 (3), only the portions irradiated with the electron beam are bonded to each other.

  In the present invention, it is preferable to press the stacked films 10 and 20 using a roller 6 or the like as shown in FIG. 4 immediately after irradiating the film with an electron beam. Since the surfaces of the films 10 and 20 are uneven at the micro level as shown in FIG. 4, even if the films are overlapped, they are not completely adhered to each other, and the contact area at the contact interface between the films is small. In this invention, since the contact area in the adhesive surface of both films increases by pressing the films 10 and 20 with the roller 6 etc. immediately after irradiating an electron beam, adhesiveness improves.

  After the laminated film 20 and the polyolefin resin film 20 are overlapped, when the laminated body 1 is pressed, it is preferable to press both the films 10 and 20 while heating. By pressing while heating, the flexibility of the films 10 and 20 is improved, and the contact area at the interface (adhesion surface) of the films 10 and 20 can be further increased, so that the adhesion is further improved. The heating temperature may be any temperature at which the film can be thermally deformed, although it depends on the type of film to be used. For example, the heating can be performed at a temperature higher than the glass transition temperature of the resin constituting the film. For example, when a laminated film having a polyethylene terephthalate base material and a polyethylene film are laminated, the heating temperature is 80 to 180 ° C, preferably 130 to 160 ° C. If the heating temperature is too high, the generated radicals are deactivated, and a strong bond cannot be realized. The pressing force (contact pressure) may be increased, and the heating temperature can be lowered by increasing the contact pressure.

  In order to press the laminated body 1 which laminated | stacked the laminated | multilayer film 20 and the polyolefin resin film 10, the heat roller 6 etc. can be used conveniently as above mentioned. Further, as shown in FIG. 4, the support roller 7 may be placed at a position facing the heat roller 6 so that the superposed film can be pressed between the heat roller 6 and the support roller 7. . In this way, by placing the support roller 7 at a position facing the heat roller 6, the contact between the laminated body (10, 20) and the heat roller 6 is brought close to the line contact, and the heat roller 6 is laminated by heat. Deformation occurring in the body (10, 20) can be minimized.

  FIG. 5 is a schematic view showing another embodiment of the manufacturing method according to the present invention. In the process of laminating and adhering the laminated film 20 and the polyolefin resin film 10, each film 10, 20 is guided to the electron beam irradiation position 3 by a guide roller, and the film 10, 20 is irradiated with the electron beam 4 before being heated. The process of pressing the films 10 and 20 with the roller 6 is continuously performed. Each film 10, 20 may be supplied in roll form.

  When irradiating each film with the electron beam 4 from the electron beam irradiation apparatus 3, it is preferable to irradiate the electron beam 4 from the film side with a smaller thickness. Since the electron beam has the property that its transmission power increases as the acceleration voltage increases, depending on the thickness of the film, the electron beam may reach the other film when irradiated with the electron beam from one of the film sides. May not arrive. In that case, the electron beam can reach the deep part of the other film by increasing the acceleration voltage of the electron beam, but unnecessary irradiation is performed on the film itself as the electron beam energy increases. It will deteriorate. Therefore, when a thick film and a thin film are laminated and bonded, it is preferable to irradiate an electron beam from the thin film side without increasing the electron beam energy so much. For example, when the thickness of the laminated film is 25 μm or less and the thickness of the polyethylene resin film is 50 μm or more, the electron beam is irradiated from the laminated film side. By adopting such an electron beam irradiation method, deterioration of the film can be minimized.

  When the films 10 and 20 to be superimposed are both thick, another electron is placed at a position facing the electron beam irradiation device 3 so that an electron beam can be irradiated from both film sides as shown in FIG. A line irradiation device 3 ′ may be provided. According to this aspect, since the irradiation energy of an electron beam can be adjusted according to the thickness of a film, both films can be adhere | attached, without deteriorating a film.

  FIG. 6 is a schematic view showing an embodiment of another manufacturing method according to the present invention. In this embodiment, the electron beam irradiation is performed before the laminated film 20 and the polyolefin resin film 10 are overlapped. First, a pair of supplied films (laminated film 20 and polyolefin resin film 10) are transferred to film 10 (20) by electron beam irradiation device 3 (3 ′) before both films 10 and 20 are overlapped. The electron beam 4 (4 ′) is irradiated. In the embodiment shown in FIG. 7, both the films 10 and 20 are overlapped so that the surfaces opposite to the electron beam irradiation side of the films 10 and 20 face each other, whereas in the embodiment shown in FIG. The difference is that the films 10 and 20 are overlapped so that the surfaces of the films 10 and 20 on the electron beam irradiation side face each other. Thus, by superimposing the other film 20 on the surface of the film 10 irradiated with the electron beam, the irradiation energy of the electron beam can be made smaller regardless of the thickness of the film. As a result, the film Degradation due to electron beam irradiation can be further reduced.

  Also in the embodiment shown in FIG. 6, a pair of electron beam irradiation devices 3 and 3 ′ are provided, and in the same manner as in the embodiment shown in FIG. 5, an electron beam is supplied to each of the laminated film 20 and the polyolefin resin film 10. 4,4 ′ may be irradiated. By these combinations, the deterioration of the film can be further reduced and the adhesive strength can be improved.

  FIG. 7 is a schematic view showing another embodiment of the manufacturing method according to the present invention. In this embodiment, the laminated film 20 and the polyolefin resin film 10 are overlapped and pressed by the heat roller 6 and then irradiated with an electron beam. First, the pair of supplied films 10 and 20 are led to a guide roller and overlapped. Subsequently, both the films 10 and 20 are pressed by the heat roller 6 and the support roller 7, and heating is performed by the heat roller 6. Thereafter, the electron beam irradiation device 3 irradiates the surfaces of the films 10 and 20 with the electron beam 4 so that the films 10 and 20 are continuously bonded. In the embodiment shown in FIG. 7, a pair of electron beam irradiation devices 3 and 3 ′ are provided, and both the electron beams 4 and 20 are respectively applied to both films 10 and 20 similarly to the embodiment shown in FIGS. 5 and 6. 4 'may be irradiated. By these combinations, the deterioration of the film can be further reduced and the adhesive strength can be improved.

  The irradiation energy of the electron beam needs to be appropriately adjusted according to the film thickness and the like as described above. In the present invention, the electron beam is irradiated in an irradiation energy range of about 20 to 750 kV, preferably 25 to 400 kV, and more preferably about 30 to 300 kV. However, the irradiation energy is preferably lower, and 40 to 120 kV. Can do. Thus, by setting it as low irradiation energy, not only deterioration of a film can be suppressed, but since radical generation | occurrence | production of a film surface occurs more efficiently, stronger bond can be implement | achieved. The absorbed dose of the electron beam is 10 to 500 kGy, preferably 50 to 300 kGy, more preferably 75 to 125 kGy.

  As such an electron beam irradiation apparatus, a conventionally known apparatus can be used. For example, a line irradiation type low energy electron beam irradiation apparatus (EB-ENGINE, manufactured by Hamamatsu Photonics Co., Ltd.) can be preferably used.

When irradiating with an electron beam, the oxygen concentration is preferably 100 ppm or less. This is because, when an electron beam is irradiated in the presence of oxygen, ozone is generated, which adversely affects the environment and the surface of the laminated film reacts with ozone to change the gas barrier characteristics.
In order to reduce the oxygen concentration to 100 ppm or less, the film may be irradiated with an electron beam in a vacuum or in an inert gas atmosphere such as nitrogen or argon. For example, by filling the electron beam irradiation apparatus with nitrogen, A concentration of 100 ppm or less can be achieved.

  The laminate obtained by laminating the laminate film and the polyolefin resin film obtained by the above-described adhesion method can realize an adhesive strength equal to or higher than that obtained by using a conventional laminate resin. In addition, since no laminate resin or the like is used, foreign matter and residual solvent do not ooze out when using a laminate, and the weather resistance is excellent.

<Preparation of film>
Using a biaxially stretched polyethylene terephthalate film having a thickness of 12 μm, an aluminum oxide thin film was formed on one surface of the film so as to have a film thickness of 20 nm using a vapor deposition apparatus under the following conditions.
Deposition conditions:
Degree of vacuum in the deposition chamber (after introducing oxygen): 2 × 10 ⁻⁴ mbar
Vacuum degree in the winding chamber: 5 × 10 ⁻³ mbar
Electron beam power: 25kW

Next, a hydrolyzed liquid having the following composition II is added to a mixed liquid containing a polyvinyl alcohol solution having the following composition I, isopropyl alcohol and ion-exchanged water, and the mixture is sufficiently stirred to form a coating solution for forming a gas barrier protective layer. And prepared.
Composition I:
Polyvinyl alcohol 2.33 (mass%)
Isopropyl alcohol 2.70 (mass%)
Water 51.75 (mass%)
Composition II (hydrolyzed solution):
Ethyl silicate 16.60 (mass%)
Silane coupling agent 1.66 (mass%)
Isopropyl alcohol 3.90 (mass%)
0.5N hydrochloric acid aqueous solution 0.53 (mass%)
Water 20.53 (mass%)
Total 100.00 (mass%)

  The above coating liquid is coated on the aluminum oxide thin film by a gravure roll coating method, and then heat-treated at 180 ° C. for 60 seconds to form a gas barrier protective layer having a thickness of 0.2 μm (dry operation state). As a result, a laminated film was obtained.

Moreover, the following three types of films were prepared as polyolefin resin films.
(1) Unstretched linear low-density polyethylene film having a thickness of 70 μm (Evolue SP2020, manufactured by Prime Polymer Co., Ltd.)
(2) Random copolymerization type polypropylene film of 70 μm (Prime Polypro J232WA, manufactured by Prime Polymer Co., Ltd.)
(3) 70 μm thick block copolymer type polypropylene film (PF380A, manufactured by Acid Allomer Co., Ltd.)

Example 1
For the prepared laminated film and the polyethylene film of (1) above, a survey scan of the gas barrier protective layer surface of the laminated film and the surface of the polyethylene film is performed using an X-ray photoelectron analyzer (ESCA-5600, manufactured by Perkin Elmer). The elements present on the film surface were detected, and the detected element peaks were subjected to narrow scan to identify the binding state. The measurement conditions were as follows.
XPS measurement conditions:
Measurement area 0.4mmφ
X-ray used AlKα ray Acceleration voltage 10kV
Survey scan 1100-0eV

  The spectra obtained by XPS measurement for the laminated film and the polyethylene film were as shown in FIGS. 8 and 9, respectively. As shown in FIG. 8, it was confirmed that O atoms, C atoms, and Si atoms exist on the gas barrier protective layer surface of the laminated film. In addition, as shown in FIG. 9, it was confirmed that C atoms and O atoms exist on the polyolefin film surface.

<Production of laminate>
Samples obtained by cutting the laminated film and the polyethylene film of (1) above into a size of 150 mm × 90 mm were prepared, and an electron beam irradiation device (line irradiation type low energy electron beam irradiation device EES-L-DP01, Hamamatsu Photonics Co., Ltd.) Placed side by side on a sample stand. Under the present circumstances, the laminated | multilayer film was mounted so that the surface in which the gas barrier property protective layer was formed may become an upper surface. Further, in order to provide a portion where the sample is not irradiated with the electron beam, masking is performed on one end portion of both samples of about 5 to 10 mm.

Next, after purging with nitrogen gas so that the oxygen concentration in the chamber of the electron irradiation apparatus becomes 100 ppm or less, the surface of the sample was irradiated with an electron beam under the following electron beam irradiation conditions.
Voltage: 40-70kV
Current: 0.75 to 2.20 mA
Irradiation dose: 75-125 kGy
In-apparatus sample transport speed: 1 to 6 m / min In-apparatus oxygen concentration: 100 ppm or less

  After irradiating the electron beam, the sample was taken out from the apparatus, immediately overlapped so that the electron beam irradiation surface sides of both films faced each other, and a roll speed of 3 m / min was used using a rubber heating roll set at 150 ° C. Then, both films were bonded under a lamination condition of pressure 0.6 MPa to obtain a laminate.

In addition, in order to measure the radicals generated and the amount of radicals remaining in the obtained laminate, using an ESR measurement device (JES-TE200, manufactured by JEOL Ltd.), the spin concentration (that is, under the following measurement conditions) Radical concentration) was calculated.
ESR measurement conditions:
Measuring magnetic field 337 ± 15mT
Microwave power 1mW
Modulation magnetic field 0.2mT
Amplification factor 1000 times Standard sample DPPH standard sample

From the ESR measurement results, it was confirmed that 6.5 × 10 ¹⁶ atoms / g of radicals were present on the laminated film side of the laminate. Further, it was confirmed that 5.5 × 10 ¹⁷ radicals / g of radicals were present on the polyethylene film side.

<Identification of adhesion state of laminate>
In the obtained laminate, the following experiment was conducted in order to confirm that a covalent bond was formed between the silicon atom on the laminated film side and the carbon atom on the polyethylene film side. First, from the portion of the obtained laminate that has been masked so that it is not irradiated with an electron beam, both films are forcibly separated, separated into a laminate film and a polyethylene film, and each separated “lamination” The XPS measurement was performed on the “film” portion and the “polyethylene film” portion using the X-ray photoelectron analyzer in the same manner as described above, The present element was detected, and the detected element peak was subjected to narrow scan to identify the bonding state.

  The spectra obtained by XPS measurement on the release surface of the laminated film (that is, the gas barrier protective layer surface) and the release surface of the polyethylene film were as shown in FIGS. 10 and 11, respectively. As shown in FIG. 10, it was confirmed that Si atoms disappeared although O atoms and C atoms were present on the release surface (gas barrier protective layer surface) of the laminated film. Further, it was confirmed that the peak of the O atom was reduced as compared with the spectrum of FIG. Thus, since there is no Si atom on the gas barrier protective layer surface of the laminated film after peeling, only a part of O atoms and C atoms are present, the polyethylene film is forced to peel off both films. A part of the surface layer of the film remains on the laminated film side, and it can be assumed that Si atoms existing on the surface of the gas barrier protective layer are covered with the remaining polyethylene, and the atoms in the gas barrier protective layer of the laminated film It turns out that the covalent bond was formed between the atoms in polyethylene. Moreover, as shown in FIG. 11, it was confirmed that C atoms and O atoms exist on the release surface of the polyethylene film, but the polyethylene film surface state after the release (FIG. 11) Compared with the surface state of FIG. 9 (FIG. 9), the peak of O atoms was reduced and the abundance of O atoms was reduced. This is because when the O atoms in the polyethylene film existing before the electron beam irradiation formed a covalent bond with the atoms in the gas barrier protective layer of the laminated film by the electron beam irradiation, both the films were forcibly separated. It can be inferred that a part of the surface layer of the polyethylene film remains on the laminated film side, and the extreme surface layer of the polyethylene film is peeled off to form a clean surface (a surface where no O atom is present).

<Evaluation of adhesive strength of laminate>
The obtained laminate was cut into a strip shape with a width of 15 mm, and a 90 ° peel test was performed at a rate of 50 mm / min using a tensile tester (Tensilon Universal Material Tester RTC-1310A, manufactured by ORIENTEC). went. The evaluation results were as shown in Table 1 below.

Examples 2-17
Except for changing the irradiation conditions of the electron beam to the laminated film and the polyethylene film, and using a heat seal device (TP-701B, manufactured by Tester Sangyo Co., Ltd.) instead of the heat roll as the bonding method of both films. In the same manner as in Example 1, a laminate was obtained. The heat seal conditions were a seal temperature of 160 ° C., a seal pressure of 0.4 MPa, a seal time of 10 seconds, and a seal width of 15 mm. Two layers of the overlapped films were sealed to obtain a laminate. In addition, heat sealing was performed so that the heat-sealed part crossed the cross in the center part of both films. The acceleration voltage, absorbed dose, and heat seal conditions (temperature and time) of the changed electron beam were as shown in Table 1 below.

Example 18
A laminate was obtained in the same manner as in Example 1 except that the random copolymer type polypropylene film (2) was used instead of the polyethylene film (1) as the polyolefin film. In addition, the obtained laminate was evaluated for adhesion in the same manner as in Example 1.

Example 19
A laminate was obtained in the same manner as in Example 2, except that the random copolymer type polypropylene film (2) was used instead of the polyethylene film (1) as the polyolefin film. Further, the obtained laminate was subjected to adhesion evaluation in the same manner as in Example 2.

Example 20
A laminate was obtained in the same manner as Example 3 except that the random copolymer type polypropylene film (2) was used instead of the polyethylene film (1) as the polyolefin film. Further, the obtained laminate was subjected to adhesion evaluation in the same manner as in Example 3.

Example 21
A laminate was obtained in the same manner as in Example 4, except that the random copolymer type polypropylene film (2) was used instead of the polyethylene film (1) as the polyolefin film. Further, adhesion evaluation was performed on the obtained laminate in the same manner as in Example 4.

Example 22
A laminate was obtained in the same manner as in Example 12, except that the random copolymer type polypropylene film (2) was used instead of the polyethylene film (1) as the polyolefin film. Further, the obtained laminate was subjected to adhesion evaluation in the same manner as in Example 12.

Example 23
A laminate was obtained in the same manner as in Example 20 except that the heat sealing time at the time of adhesion between the laminated film and the random copolymer type polypropylene film was changed from 10 seconds to 5 seconds. Further, the obtained laminate was evaluated for adhesion in the same manner as in Example 20.

Example 24
A laminate was obtained in the same manner as in Example 1 except that the block copolymer type polypropylene film (3) was used instead of the polyethylene film (1) as the polyolefin film. In addition, the obtained laminate was evaluated for adhesion in the same manner as in Example 1.

Example 25
A laminate was obtained in the same manner as in Example 2 except that instead of the polyethylene film of (1) above, the block copolymer type polypropylene film of (3) above was used as the polyolefin film. Further, the obtained laminate was subjected to adhesion evaluation in the same manner as in Example 2.

Comparative Example 1
In Example 1, a laminate was prepared in the same manner as in Example 1 except that the electron beam irradiation was not performed, and adhesion evaluation was performed in the same manner as in Example 1. However, the obtained laminated body did not adhere to each other's film without performing a peel test.

Comparative Example 2
The laminated film and the polyethylene film used in Example 1 were superposed through a urethane adhesive having the following composition in place of electron beam irradiation, and the roll speed was set to 150 ° C. using a rubber heating roll. A laminate was prepared in the same manner as in Example 1 except that the two films were bonded together under a lamination condition of 3 m / min and a pressure of 0.6 MPa, and adhesion evaluation was performed in the same manner as in Example 1.
<Urethane adhesive composition>
Main agent: RU0004 (Rock Paint)
Hardener: H-1 (manufactured by Rock Paint)
Mixing ratio: main agent / curing agent = 7.47 / 1 (weight ratio)
Solvent: ethyl acetate

DESCRIPTION OF SYMBOLS 1 Laminated body 10 Polyolefin resin film 20 Laminated film 21 Thermoplastic resin film 22 Aluminum oxide thin film layer 23 Gas barrier property protective layer 3, 3 'Electron beam irradiation apparatus 4, 4' Electron beam 5 Film base material contact interface 6 Heat roller 7 Support roller

Claims (6)

A layered product in which a layer containing an alkoxysilane and a polyolefin resin film are laminated by being pressed at a temperature of 80 to 180 ° C. after being irradiated with an electron beam ,
In at least part of the layer containing the alkoxysilane and the polyolefin resin film, a covalent bond is formed between the silicon atom in the layer containing the alkoxysilane and the carbon atom in the polyolefin resin film, A laminate comprising an alkoxysilane-containing layer and the polyolefin resin film bonded without an adhesive. The laminate according to claim 1, wherein a covalent bond of C—O bond and / or C═O bond is further formed between the gas barrier protective layer and the polyolefin resin film . A method for producing a laminate in which an alkoxysilane-containing layer and a polyolefin resin film are laminated,
There line electron beam irradiation of at least one surface, a layer and / or the polyolefin resin film containing an alkoxysilane,
Between the silicon atom in the layer containing the alkoxysilane and the carbon atom in the polyolefin resin film, the layer containing the alkoxysilane and the polyolefin resin film are overlapped and pressed at a temperature of 80 to 180 ° C. Forming a covalent bond, and bonding the layer surface containing the alkoxysilane and the polyolefin resin film surface. The method according to claim 3 , wherein electron beam irradiation is performed before and / or after the layer containing the alkoxysilane and the polyolefin resin film are overlapped. The method according to claim 3 or 4 , wherein an acceleration voltage of the electron beam irradiation is in a range of 40 to 120 kV. The method according to any one of claims 3 to 5, wherein the electron beam irradiation is performed in an atmosphere having an oxygen concentration of 100 ppm or less.

Images