JP2013018166A - Laminate and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate which is obtained by sticking a polyimide resin film to a polyolefin resin film without using an adhesive, from which foreign matter, a residual solvent or the like does not ooze out, and which is excellent in strength, heat resistance, electrical insulation properties, chemical resistance and heat sealability.SOLUTION: The laminate is obtained by layering the polyimide resin film on the polyolefin resin film. In at least a part of the polyimide resin film and the polyolefin resin film, bonding is formed between an atom in the polyimide resin film and an atom in the polyolefin resin film, and the polyimide resin film and the polyolefin resin film are stuck to each other without interposing adhesive.

Description

  The present invention relates to a laminate, and more particularly, to a laminate in which a polyimide resin film and a polyolefin resin film are bonded without using an adhesive and a method for producing the same.

  Polyimide resins are used in electrical and electronic applications because of their excellent heat resistance, electrical insulation and chemical resistance, and excellent mechanical properties. For example, it is used to form insulating films and protective coatings on semiconductor devices, surface protective materials such as flexible circuit boards and integrated circuits, base resin, and fine circuit interlayer insulating films and protective films. . In these applications, in addition to the case where a polyimide resin film is used alone, a laminated body obtained by bonding a polyimide resin film and another resin film may be used.

  As a laminate of a polyimide resin film and another resin film, for example, it is attempted to laminate a polyimide resin film and a polyolefin resin film via an adhesive. By laminating a resin film having heat sealability such as a polyolefin resin film to a polyimide resin film to form a laminate, when laminating this laminate to other members, by heat sealing the resin film side, A laminate made of a polyimide resin film can be easily bonded to another member. However, in a laminate obtained by laminating and bonding, depending on the use environment of the laminate, the adhesive component may gradually elute or volatilize from the laminate, and there is a problem of contamination by the adhesive component. In addition, the adhesive itself may deteriorate due to long-term use, and the weather resistance of the laminate may become a problem particularly in applications exposed to ultraviolet rays and heat. In addition, in the laminating technique using an adhesive, since a resin component diluted in a solvent is generally applied, the solvent may remain after the laminated body is assembled into a final product. .

  In addition, it is conceivable that the polyolefin resin film is directly bonded to the polyimide resin film by heat sealing, but since the polyimide resin is a resin having excellent heat resistance, the molten polyolefin resin film is not fused to the polyimide resin film, A laminate in which both films are firmly adhered cannot be obtained.

  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 1) 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 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 different types of materials are bonded to each other, they can be bonded firmly to each other without using a laminate resin or the like by irradiating the film with an electron beam. And even if it is the laminated body which adhered conventionally with the adhesive like the laminated body of a polyimide resin film and a polyolefin resin film, according to electron beam irradiation, it is not necessary to use an adhesive agent A bond is formed between an atom on the polyimide resin film side and an atom on the polyolefin resin film side, or a bond is formed through an oxygen atom, a nitrogen atom or a hydroxyl group, and can be firmly bonded to each other. I got the knowledge. The present invention is based on this finding.

  Accordingly, an object of the present invention is a laminate in which a polyimide resin film and a polyolefin resin film are bonded without using an adhesive, and has excellent strength, heat resistance, electrical insulation, chemical resistance, and heat sealability. It is providing the laminated body which has this.

The laminate according to the present invention is a laminate in which a polyimide resin film and a polyolefin resin film are laminated,
In at least a part of the polyimide resin film and the polyolefin resin film, a bond is formed between an atom in the polyimide resin film and an atom in the polyolefin resin film, and the polyimide resin film and the polyolefin resin The film is bonded to the film without using an adhesive.

  Further, as an aspect of the present invention, at least part of the interface between the polyimide resin film and the polyolefin resin film, between the atoms in the polyimide resin film and the atoms in the polyolefin resin film, oxygen atoms, A bond is preferably formed through a nitrogen atom or a hydroxyl group.

  Moreover, as an aspect of the present invention, the polyimide resin film is preferably an aromatic polyimide resin film obtained from pyromellitic dianhydride and 4,4'-diaminodiphenyl ether.

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

Moreover, the production method as another aspect of the present invention is a method for producing a laminate in which a polyimide resin film and a polyolefin resin film are laminated,
At least one surface of the polyimide resin film and / or the polyolefin resin film is irradiated with an electron beam,
The polyimide resin film surface and / or the polyolefin resin film surface irradiated with the electron beam are superposed and bonded together.

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

  Moreover, as another aspect of the present invention, it is preferable to press the adhesion between the polyimide resin film and the polyolefin resin film, and the heating between the polyimide resin film and the polyolefin resin film is preferably performed. preferable.

  According to the present invention, in a laminate in which a polyimide resin film and a polyolefin resin film are laminated, a bond is formed between atoms in the polyimide resin film and atoms in the polyolefin resin film, or oxygen atoms, Since a bond is formed through a nitrogen atom or a hydroxyl group, a laminate in which the polyimide resin film and the polyolefin resin film are firmly bonded can be obtained even if the bonding is not performed through an adhesive. As a result, a laminate excellent in strength, heat resistance, electrical insulation, chemical resistance, and heat sealability can be realized.

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.

  Hereinafter, the laminated body by this invention is demonstrated, referring drawings. As shown in FIG. 1, the laminate according to the present invention has a structure in which a polyimide resin film 2 and a polyolefin resin film 1 are laminated without using an adhesive.

  By forming a bond between an atom of the polyolefin resin film 1 and an atom of the polyimide resin film 2 on at least a part of the adhesive surfaces of the polyolefin resin film 1 and the polyimide resin film 2, the polyolefin resin film 1 and the polyimide resin are formed. The film 2 is firmly bonded. Usually, even if a polyimide resin film is laminated on the surface of a polyolefin resin film, a hydrogen bond or a covalent bond is not formed between the two, so that the two cannot be bonded unless an adhesive is used. Moreover, in heat sealing, as mentioned above, it cannot be set as the laminated body which both films adhered firmly. In the present invention, as described later, the surface of the polyolefin resin film 1 and / or the polyimide resin film 2 is irradiated with an electron beam to generate radicals, and as shown in FIG. A bond is formed between the surface of the polyimide resin film 2 and the atoms on the surface of the polyolefin resin film 1 and the atoms on the surface of the polyimide resin film 2 through oxygen atoms and / or nitrogen atoms. By forming the film, the polyolefin resin film 1 and the polyimide resin film 2 are firmly bonded without using an adhesive. Further, radicals generated by electron beam irradiation and oxygen in the air are combined, and there may be OH groups on the surface of the polyolefin resin film 1 and / or the polyimide resin film 2, in which case the polyolefin resin film A hydrogen bond may be formed between 1 and the polyimide resin film 2. The generation of radicals by electron beam irradiation is confirmed by identifying the free radical species existing in the film after electron beam irradiation using an electron spin resonance apparatus (hereinafter also referred to as ESR). be able to.

  Further, in the laminate in which the polyimide resin film 2 and the polyolefin resin film 1 are bonded by electron beam irradiation, as shown in FIG. 2, bonds are formed between atoms in the polyimide resin film and atoms in the polyolefin resin film. Therefore, even if no adhesive is used, a laminate that does not peel can be obtained. 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 the polyimide resin film 2 and the polyolefin resin film 1 are bonded only by hydrogen bonding, when the laminate is immersed in water or an alcohol solution, the hydrogen bond formed between the two is broken and water or Since hydrogen bonds with alcohol hydrogen atoms or oxygen atoms are reformed, the adhesive force is lost and both films are peeled off. Therefore, it can be confirmed whether the adhesion is due to a covalent bond and a hydrogen bond or only due to a hydrogen bond.

  Hereinafter, the polyimide resin film and the polyolefin resin film constituting the laminate according to the present invention will be described.

<Polyimide resin film>
The polyimide resin film used in the present invention is a polyamic acid (polyamic acid) which is a polyimide precursor by polycondensing an aromatic tetracarboxylic acid anhydride and an aromatic diamine, and the resulting polyamic acid is A film formed from a polymer imidized by heating or using a catalyst.

  Aromatic tetracarboxylic acid anhydrides include carboxylic acid anhydrides such as 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetra. Carboxylic dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, 1,1-bis (2,3- Dicarboxyphenyl) ethane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 2,3,6,7-naphthalenetetracarboxylic Acid dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 1,2,5,6-naphthalene tetracarboxylic dianhydride, 3,4,9,10-perylene tetracarboxylic acid bis Nothing 1,2,7,8-phenanthrenetetracarboxylic dianhydride, oxydiphthalic dianhydride, pyromellitic dianhydride, 4,4'-hexafluoroisopropylidenediphthalic anhydride, etc. And dianhydrides of carboxylic acid compounds.

  As aromatic diamines, m-phenylenediamine, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, bis (3-aminophenyl) sulfide, (3-aminophenyl) (4-aminophenyl) Sulfide, bis (3-aminophenyl) sulfoxide, bis (4-aminophenyl) sulfoxide, (3-aminophenyl) (4-aminophenyl) sulfoxide, bis (3-aminophenyl) sulfone, bis (4-aminophenyl) Sulfone, (3-aminophenyl) (4-aminophenyl) sulfone, 3,3′-diaminobenzophenone, 3,4′-diaminobenzophenone, 3,3′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 1, 3-bis (3-aminophenoxy) Zen, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (3- Aminophenoxy) biphenyl, 4,4′-bis (4-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] ketone, bis [4 -(3-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4- (3-aminophenoxy) phenyl] sulfoxide, bis [4- (4-aminophenoxy) phenyl Sulfoxide, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) Enyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, 1,4-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (3-aminophenoxy) Benzoyl] benzene, 4,4′-bis [3- (4-aminophenoxy) benzoyl] diphenyl ether, 4,4′-bis [3- (3-aminophenoxy) benzoyl] diphenyl ether, 3,3′-diamino-4 , 4′-diphenoxybenzophenone, 4,4′-diamino-5,5′-diphenoxybenzophenone, 3,4′-diamino-4,5′-diphenoxybenzophenone, 3,3′-diamino-4-phenoxy Benzophenone, 4,4'-diamino-5-phenoxybenzophenone, 3,4'-diamino-4-phenoxybenzo Phenone, 3,4′-diamino-5′-phenoxybenzophenone, 3,3′-diamino-4,4′-dibiphenoxybenzophenone, 4,4′-diamino-5,5′-dibiphenoxybenzophenone, 3,4 '-Diamino-4,5'-dibiphenoxybenzophenone, 3,3'-diamino-4-biphenoxybenzophenone, 4,4'-diamino-5-biphenoxybenzophenone, 3,4'-diamino-4-biphenoxy Benzophenone, 3,4'-diamino-5'-biphenoxybenzophenone, 1,3-bis (3-amino-4-phenoxybenzoyl) benzene, 1,4-bis (3-amino-4-biphenoxybenzoyl) benzene 1,3-bis (4-amino-5-biphenoxybenzoyl) benzene, 1,4-bis (4-amino) 5-biphenoxybenzoyl) benzene, 1,3-bis (3-amino-4-biphenoxybenzoyl) benzene, 1,4-bis (3-amino-4-biphenoxybenzoyl) benzene, bis (trifluoromethyl) -1,1'-biphenyl-4,4'-diamine and the like.

  Among the combinations of the aromatic tetracarboxylic acid anhydride and the aromatic diamine, an aromatic polyimide resin obtained from pyromellitic dianhydride and 4,4′-diaminodiphenyl ether can be preferably used.

  Various additives such as a heat stabilizer and a flame retardant can be added to the polyimide resin during the manufacturing process or in the subsequent processing steps as necessary within a range not impairing the performance.

  The method for producing a film from the above polyimide resin is not particularly limited, and a known method can be adopted. For example, a polyamic acid solution obtained by polycondensation is cast on a substrate, such as casting, spin coating, roll coating, etc. After coating to an appropriate thickness by the method, the film is heated at a temperature of 100 to 300 ° C. to remove the solvent and imidize to obtain a film-like polyimide resin.

  A commercially available polyimide resin film may be used. For example, Kapton (manufactured by Toray DuPont), Apical (manufactured by Kaneka Chemical Co., Ltd.), or the like can be suitably used.

<Polyolefin resin film>
As the polyolefin resin film constituting the laminate of the present invention, low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene, polymethylpentene and the like alone, or polypropylene and low density polyethylene And a film made of a mixture of polypropylene and high-density polyethylene can be used. Polymethylpentene has excellent performance in gas permeability, chemical resistance, oil resistance, and the like. As such a resin film, you may use a commercially available thing, for example, a TPX film (made by Mitsui Chemicals) etc. can be used conveniently. 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. For example, phenol-based, phosphorus-based, hindered amine-based light absorbers, benzotriazole-based, benzophenone-based, and salicylic acid ester-based ultraviolet absorbers are used. it can.

  The laminated body in which the polyimide resin film and the polyolefin resin film are laminated and bonded as described above does not exude foreign matter or residual solvent even when the laminated body is used, and the strength, heat resistance, electrical insulation Excellent in chemical properties, chemical resistance and heat sealability.

<Method for producing laminate>
Next, a method for producing the laminate as described above will be described with reference to the drawings. First, the polyolefin resin film 1 and the polyimide resin film 2 described above are prepared (FIG. 3 (1)), and either or both of them 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, immediately after irradiating the film with an electron beam, it is preferable to press the overlapped polyolefin resin film 1 and polyimide resin film 2 using a roller 6 or the like as shown in FIG. Since the surfaces of both films 1 and 2 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 both films is small. . In this invention, since the contact area in the adhesive surface of both films increases by pressing the polyolefin resin film 1 and the polyimide resin film 2 with the roller 6 etc. immediately after irradiating an electron beam, adhesiveness improves. .

  After the polyolefin resin film 1 and the polyimide resin film 2 are overlaid, when pressing both the films 1 and 2, it is preferable to press both the films 1 and 2 while heating. By pressing while heating, the flexibility of the polyolefin resin film 1 and the polyimide resin film 2 is improved, and the contact area at the interface (adhesive surface) between the films 1 and 2 can be further increased. Will be improved. The heating temperature may be any temperature at which the film can be thermally deformed, depending on the type of material 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 superposing a polyolefin resin film and a polyimide resin film, the heating temperature is 80 to 180 ° C, preferably 100 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 overlap and press the polyolefin resin film 1 and the polyimide resin film 2, the heat roller 6 or the like can be suitably used as described above. Further, as shown in FIG. 4, even if the support roller 7 is placed at a position facing the heat roller 6 so that the stacked laminate can be pressed between the heat roller 6 and the support roller 7. Good. In this way, by placing the support roller 7 at a position facing the heat roller 6, the contact between the laminate (the laminate of the film 1 and the film 2) and the heat roller 6 is brought close to the line contact, and the heat roller 6. It is possible to minimize the deformation that occurs in the laminated body due to the heat from the.

  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 polyolefin resin film 1 and the polyimide resin film 2, the polyolefin resin film 1 and the polyimide resin film 2 are respectively guided to the electron beam irradiation position 3 by the guide rollers, and the electron beam 4 is connected to both the films 1. , 2 is continuously performed by pressing the two films 1 and 2 with the heat roller 6 after irradiation. Each of the polyolefin resin film 1 and the polyimide resin film 2 may be supplied in a roll form.

  When the electron beam irradiation device 3 irradiates the polyolefin resin film 1 and the polyimide resin film 2 with the electron beam 4, it is preferable to irradiate the electron beam 4 from the material side having 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 material, it can reach the other film or film when the electron beam is irradiated from either material side. The electron beam may not reach. In that case, the electron beam can reach the deep part of the other material by increasing the acceleration voltage of the electron beam. However, as the electron beam energy increases, the material (film) itself made of resin Unnecessary irradiation is performed and deteriorates. 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 polyolefin resin film is 25 μm or less and the thickness of the polyimide resin film is 50 μm or more, the electron beam is irradiated from the polyolefin resin film side. By adopting such an electron beam irradiation method, deterioration of the film can be minimized.

  When both the films 1 and 2 to be superimposed are thick, as shown in FIG. 5, another electron beam irradiation device is placed at a position facing the electron beam irradiation device 3 so that the electron beam can be irradiated from both. 3 'may be provided. According to this aspect, since the irradiation energy of the electron beam can be adjusted according to the thickness of the film, the films can be bonded to each other without deteriorating the 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 polyolefin resin film 1 and the polyimide resin film 2 are overlapped. First, a pair of supplied films (polyolefin resin film 1 and polyimide resin 2) are transferred to film 1 (2) by electron beam irradiation device 3 (3 ′) before both films 1 and 2 are overlaid. The electron beam 4 (4 ′) is irradiated. In the embodiment shown in FIG. 5, both the films 1 and 2 are overlapped so that the surfaces opposite to the electron beam irradiation side of the polyolefin resin film 1 and the polyimide resin film 2 face each other. The embodiment shown is different in that the films 1 and 2 are overlapped so that the surfaces on the electron beam irradiation side of the films 1 and 2 face each other. Thus, by superimposing the other film 2 on the surface of the film 1 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 electrons are respectively transferred to the polyolefin resin film 1 and the polyimide resin film 2 in the same manner as the embodiment shown in FIG. 5. Lines 4 and 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 polyolefin resin film 1 and the polyimide resin film 2 are overlapped and pressed by the heat roller 6 and then irradiated with an electron beam. First, the pair of supplied films 1 and 2 are led to a guide roller and overlapped. Subsequently, both the films 1 and 2 are pressed by the heat roller 6 and the support roller 7, and heating is performed by the heat roller 6. Then, the electron beam 4 is irradiated to the surface of the polyolefin resin film 1 and the polyimide resin film 2 by the electron beam irradiation apparatus 3, and both films 1 and 2 are adhere | attached continuously. Also in the embodiment shown in FIG. 7, a pair of electron beam irradiation devices 3 and 3 ′ are provided, and the electron beams 4 and 4 are respectively applied to both films 1 and 2 in the same manner as the embodiment shown in FIGS. You may irradiate. By these combinations, the film deterioration 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 30 to 400 kV, and more preferably about 40 to 200 kV, but it is preferable that the irradiation energy be lower. 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 5 to 2000 kGy, preferably 20 to 1000 kGy.

  As such an electron beam irradiation apparatus, conventionally known ones can be used. For example, a curtain type electron irradiation apparatus (LB1023, manufactured by I. Electron Beam Co., Ltd.) or 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 irradiation with an electron beam in the presence of oxygen generates ozone and may adversely affect the environment. 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 polyolefin resin film and the polyimide resin film obtained by the above-described adhesion method can realize an adhesive strength equal to or higher than that obtained by bonding using a conventional laminate resin. In addition, since no laminate resin or the like is used, foreign matter or residual solvent does not ooze out when the laminate is used, and the strength, heat resistance, dielectric properties, and electrical insulation are excellent.

<Preparation of film>
A polyimide resin film (Kapton H, manufactured by Toray DuPont) having a thickness of 50 μm was prepared as a polyimide resin film. In addition, the following two types of films were prepared as polyolefin resin films.
A: Film obtained by forming a linear low density polyethylene (Evolue SP2020, manufactured by Prime Polymer Co., Ltd.) to a thickness of 70 μm B: Film formed by forming a low density polyethylene (Novatech LD LF547C, manufactured by Nippon Polyethylene Co., Ltd.) to a thickness of 70 μm

Example 1
<Production of laminate>
Samples obtained by cutting each of the above films into a size of 150 mm × 75 mm are prepared and placed on a sample stage of an electron beam irradiation apparatus (line irradiation type low energy electron beam irradiation apparatus EES-L-DP01, manufactured by Hamamatsu Photonics Co., Ltd.). Juxtaposed. At this time, 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 kV
Absorbed dose: 200kGy
In-device oxygen concentration: 100 ppm or less

  After irradiating the electron beam, the sample was taken out from the apparatus, immediately overlapped so that both electron beam irradiation surface sides face each other, and both films were bonded by a thermal laminating method to obtain a laminate.

Example 2
In Example 1, a laminate was obtained in the same manner as in Example 1 except that the electron beam irradiation conditions were changed to the acceleration voltage and irradiation dose shown in Table 1.

Example 3
In Example 1, except that the polyolefin resin film used was changed to a B film, and the electron beam irradiation conditions were changed to the acceleration voltage and irradiation dose shown in Table 1, the laminate was prepared in the same manner as in Example 1. Obtained.

Comparative Example 1
A laminate was obtained in the same manner as in Example 1 except that electron irradiation was not performed. However, the obtained laminate was not bonded to the polyimide resin film and the polyolefin resin film.

Comparative Example 2
A laminate was obtained by a dry laminating method in which the two types of resin films used in Example 1 were bonded together via a two-component curable aromatic ester adhesive (Takelac A-3, manufactured by Mitsui Chemicals, Inc.).

<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.

  As is clear from the evaluation results in Table 1, the laminates of Examples 1 to 3 that were irradiated with the electron beam had an adhesive strength equivalent to or higher than that of the laminate of Comparative Example 2 bonded with an adhesive. Had. Moreover, the laminated bodies of Examples 1 to 3 maintain adhesiveness even after storage in water. From this result, it can be seen that in the laminates of Examples 1 to 3, the polyimide resin film and the polyolefin resin film are not bonded only by hydrogen bonds or intermolecular forces. Therefore, although indirectly, it can be inferred that a covalent bond is formed between an atom of the polyimide resin film and an atom in the polyolefin resin film.

DESCRIPTION OF SYMBOLS 1 Polyolefin resin film 2 Polyimide resin film 3, 3 'Electron beam irradiation apparatus 4, 4' Electron beam 5 Film base-material contact interface 6 Heat roller 7 Support roller

Claims (8)

A laminate in which a polyimide resin film and a polyolefin resin film are laminated,
In at least a part of the polyimide resin film and the polyolefin resin film, a bond is formed between an atom in the polyimide resin film and an atom in the polyolefin resin film, and the polyimide resin film and the polyolefin resin A laminate, wherein the film is bonded without using an adhesive.   At least part of the interface between the polyamide resin film and the polyolefin resin film, bonded between an atom in the polyamide resin film and an atom in the polyolefin resin film via an oxygen atom, a nitrogen atom, or a hydroxyl group The laminate according to claim 1, wherein   The laminate according to claim 1 or 2, wherein the polyimide resin film is an aromatic polyimide resin film obtained from pyromellitic dianhydride and 4,4'-diaminodiphenyl ether.   The laminate according to any one of claims 1 to 3, wherein the polyolefin resin film is a resin film made of polypropylene, polyethylene, or polymethylpentene. A method for producing a laminate in which a polyimide resin film and a polyolefin resin film are laminated according to any one of claims 1 to 4,
At least one surface of the polyimide resin film and / or the polyolefin resin film is irradiated with an electron beam,
A method comprising superposing and adhering the polyimide resin film surface and / or the polyolefin resin film surface irradiated with the electron beam.   The method according to claim 5, wherein electron beam irradiation is performed before and / or after the polyimide resin film and the polyolefin resin film are overlapped.   The method according to claim 5 or 6, wherein the adhesion between the polyimide resin film and the polyolefin resin film is performed under pressure.   The method according to any one of claims 5 to 7, wherein the adhesion between the polyimide resin film and the polyolefin resin film is performed by heating.

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