Patent Application
20100068528
1. Field of the Invention
The present invention relates to a laminate and a laminate production apparatus and more particularly relates to a laminate in which an underlying layer is formed on a substrate and a thin film is formed on the underlying layer by a vacuum film forming method and a laminate production apparatus.
2. Description of the Related Art
A variety of functional films (functional sheets) such as optical films including gas barrier films, protective films, optical filters and reflection preventive films, are utilized for various devices including optical elements; display devices such as liquid crystal displays and organic EL displays; semiconductor devices; and thin-film solar cells.
In production of these functional films, film formation (thin-film formation) by a vacuum film forming method, such as sputtering, and plasma CVD (Chemical Vacuum Deposition) is utilized.
Generally, in order to efficiently form a film by a vacuum film forming method while securing high productivity, a film is continuously formed on a long-length substrate.
As equipment used to carry out such film formation, there has been known a so-called roll-to-roll film forming apparatus where a feed roll around which a long-length substrate (web-formed substrate) is wound and a take-up roll around which a film-formed substrate is wound, are used. In such a roll-to-roll film forming apparatus, a long-length substrate is intercalated from a feed roll up to a take-up roll in a predetermined path where the substrate passes through a film forming chamber, in which a film is formed on the substrate by plasma CVD, and a film is continuously formed on the conveyed substrate in the film forming chamber while feeding of the substrate from the feed roll being performed in synchronization with taking-up of the substrate on which surface the film has been formed by the take-up roll.
In the meantime, functional films such as gas barrier film and protective film are not always formed in a single layer. For instance, functional films (laminated films) are also known in which an organic film containing polymer as a main component is formed on a substrate such as a plastic film, and an inorganic film formed of an inorganic material is formed on the organic film.
By way of example, there is disclosed in Japanese Patent Application Laid-Open No. 2002-264274 a gas barrier film which comprises a laminate of an organic film formed by curing a composition containing a monomer or oligomer of hexafunctional acrylate or methacrylate, and an inorganic layer of an oxide selected from an aluminum oxide, a silicone oxide, an indium/tin complex oxide, and an indium/cerium complex oxide.
In order to produce a laminate in which an underlying layer is formed on a substrate such as a plastic film, and a thin film is formed on the underlying layer by a vacuum film forming method, there is a need to perform coating under atmospheric pressure and to perform vacuum film formation under vacuum conditions. Therefore, it has been necessary to transfer the substrate from a film forming apparatus for forming an underlying layer is formed under atmospheric pressure to another film forming apparatus capable of forming a thin film under vacuum conditions. Accordingly, there has been a disadvantage that the transfer of the substrate results in adhesion of dust to the substrate.
The present invention has been made in light of the present circumstances. The present invention aims to provide a laminate having a thin film formed on an underlying layer and a laminate production apparatus which are capable of preventing dust from attaching to a substrate during transfer of the substrate.
To achieve the above object, according to a first aspect of the present invention, there is provided a laminate production apparatus comprising an A zone comprising a feeding and taking-up device which feeds a long-length substrate from a substrate roll and which takes up a laminate in which an underlying layer and a thin film are formed over the long-length substrate, and a coating device which applies a coating liquid onto the substrate to form a coated film; a B zone comprising a drying device which heat-treats the coated film; and a C zone comprising a vacuum film forming device which forms the thin film on the underlying layer by a vacuum film forming method, and a taking-up and feeding device which takes up and feeds the long-length substrate on which surface the underlying layer is formed.
According to the first aspect of the present invention, it is possible to provide a laminate production apparatus capable of preventing dust from attaching to a substrate during transfer of the substrate. It should be noted that in the laminate production apparatus, during formation of the underlying layer, all the zones are maintained at about atmospheric pressure, and the long-length substrate is conveyed from the A zone to the B zone, and from the B zone to the C zone, and during formation of the thin film, all the zones are vacuum-drawn to be under reduced pressure, and the long-length substrate is conveyed from the C zone to the B zone, and from the B zone to the A zone, thereby producing a laminate.
According to a second aspect of the present invention, in the laminate production apparatus according to the first aspect of the present invention, the coating liquid contains a radiation curable monomer or oligomer, and the C zone further comprises an ultraviolet irradiation device which irradiates the coated film after the heat treatment to cure the coated film and form the underlying layer.
Thus, the underlying layer can be formed with the coating liquid containing the radiation curable monomer or oligomer by providing the ultraviolet irradiation device in the C zone.
According to a third aspect of the present invention, in the laminate production apparatus according to one of the first aspect and the second aspect of the present invention, the substrate is conveyed by a plurality of cylindrical rollers with a smooth surface, and the plurality of cylindrical rollers with a smooth surface convey the substrate with a surface of the substrate on which the underlying layer or the thin film is not formed being in contact with the plurality of cylindrical rollers with a smooth surface and with a surface of the substrate on which the underlying layer or the thin film is formed faced downward to the ground.
Because the substrate is conveyed with a plurality of cylindrical rollers with a smooth surface in a manner that a surface of the substrate on which the underlying layer or the thin film is not formed is in contact with the plurality of cylindrical rollers with a smooth surface and that a surface of the substrate on which the underlying layer or the thin film is formed faces downward to the ground, there is no need to use air floating rollers. Accordingly, cost for conveying a substrate becomes less expensive. Further, dust becomes hardly to attach to a surface of the substrate on which the underlying layer or the thin film is formed in the laminate production apparatus.
According to a fourth aspect of the present invention, in the laminate production apparatus according to any one of the first aspect to the third aspect of the present invention, during the formation of the underlying layer, cleaning air flows through the C zone from a top portion of the A zone, and during the formation of the thin film, the cleaning air is exhausted from a bottom portion of the C zone.
With such an air flow passage, dust becomes hardly to attach to a surface of the substrate on which the underlying layer or the thin film is formed in the laminate production apparatus.
According to a fifth aspect of the present invention, there is provided a laminate comprising multi-layers composed of the underlying layer and thin film formed by the laminate production apparatus according to any one of the first aspect to the fourth aspect.
The laminate production apparatus according to any one of the aspects of the present invention can be utilized, in particular, effectively in production of a laminate in which layers composed of an underlying layer and a thin film are formed in a stack.
According to the present invention, it is possible to provide a laminate and a laminate production apparatus each capable of preventing dust from attaching to a substrate during transfer of the substrate.
Hereinbelow, the preferred embodiments of the present invention will be described with reference to the accompanying drawings. The present invention will be described with reference to the preferred embodiments described below, however, various modifications may be made by a large number of techniques without departing from the spirit and scope of the present invention and embodiments other than the present embodiments may be utilized. Accordingly, all modifications within the present invention are included within the spirit and scope of the appended claims. Also, it should be noted that in the description of the present invention, the numerical range represented by means of “to” means a range including numerical values described before and after the numerical values described in “to”.
The following describes a laminate production apparatus according to the present invention. Note that the following is the case where a substrate for laminate is a film, however, the laminate of the present invention is not limited to a laminated film, and it is also applicable to the case where the substrate for laminate is a sheet.
As shown in
In the production of a laminate, by way of an example, a laminate (laminated film) 10 is produced by an organic film formation and an inorganic film formation. In the organic film formation, an organic film (underlying layer) 12 is formed on a surface of a substrate B, and in the inorganic film formation, an inorganic film (thin film) 14 is formed on a surface of the organic film 12.
The laminate production apparatus 20 of the present invention comprises, as illustrated in
The A zone is provided with a feeding and taking-up device 22 which feeds a long-length substrate B from a substrate roll and which takes up a laminate in which an underlying layer 12 and a thin film 14 are formed on the long-length substrate B, and a coating device 24 which applies a coating liquid containing a radiation curable monomer or oligomer onto the substrate to form a coated film.
The B zone is provided with a drying device 26 which heats the coated film that has been applied by the coating device 24.
The C zone is provided with a ultraviolet irradiation device 28 which cures the coated film that has been heated by the drying device 26 by ultraviolet radiation to form the underlying layer, a vacuum film forming device 30 which forms the thin film on the underlying layer by a vacuum film forming method, and a taking-up and feeding device 32 which takes up and feeds the long-length substrate B on which surface the underlying layer has been formed.
During the formation of the underlying layer 12, all the zones of A zone, B zone and C zone are maintained at about atmospheric pressure, and the long-length substrate B is conveyed from the A zone to the B zone, and from the B zone to the C zone.
In order to form an organic film, the coating device 24, drying device 26 and ultraviolet irradiation device 28 are used, a coating liquid which has been preliminarily prepared and contains a radiation curable monomer or oligomer is applied onto the substrate B by the coating device 24, dried by the drying device 26 and then polymerized by the ultraviolet irradiation device 28 to form the underlying layer 12.
In the organic film formation, the underlying layer is formed by roll-to-roll film forming method. The substrate B is loaded, as a substrate roll 40, into the feeding and taking-up device 22, an underlying layer is formed on its surface while being conveyed in a longitudinal direction, and the substrate B on whose surface the underlying layer is formed is taken up, as a roll 42, by a taking-up and feeding device 32.
The substrate B fed from the substrate roll 40 by the feeding and taking-up device 22 is first conveyed to the coating device 24. In the coating device 24, a surface of the substrate B is coated with a coating liquid which has been preliminarily prepared and contains a radiation curable monomer or oligomer to be formed as the underlying layer 12. As for the application of the coating liquid, all commonly used liquid coating methods can be employed.
The substrate B is subsequently conveyed to the drying device 26 in the B zone. The drying device 26, a solvent contained in the coating liquid which has been applied by the coating device 24 is dried. The heating of the coating liquid is not particularly limited, and all conventionally known heating means such as heating by a heater and heating by hot air can be used, as long as the means can heat the coating liquid depending on a conveyance speed of the substrate B and so on, before the substrate B reaches the ultraviolet irradiation device 28.
The substrate B is subsequently conveyed to the ultraviolet irradiation device 28 in the C zone. A drum 29 placed in the C zone rotates around a center axis in a clockwise direction in the figure.
In the ultraviolet irradiation device 28, the coating liquid which has been applied by the coating device 24 and heated and dried by the drying device 26 is exposed to UV (ultraviolet) rays so as to polymerize the radiation curable monomer or oligomer, thereby forming the underlying layer 12.
During the formation of the underlying layer 12, it is preferable that cleaning air be supplied from an air supplying device 48 positioned at a top portion of the A zone to flow in the direction of the C zone.
Note that when the underlying layer 12 is formed, the vacuum film forming device 30 is not used.
Next, as illustrated in
During the formation of the thin film, all the zones of A zone, B zone and C zone are vacuum-drawn to be under reduced pressure, and the long-length substrate B is conveyed from the C zone to the B zone, and from the B zone to the A zone to produce a laminate according to the embodiment of the present invention. The A zone, B zone and C zone respectively have a vacuum pumping device. Preferably, the C zone has a vacuum pumping device 50 at a bottom portion thereof. For the vacuum pumping device, a conventionally known vacuum pumping device may be used.
Similarly to the formation of the organic film, the formation of an inorganic film is carried out by roll-to-roll film forming method, in which a substrate B with an underlying layer 12 formed on a surface thereof is fed from a substrate roll 42, a thin film 14 is formed while the substrate being conveyed in a longitudinal direction, and a laminate 10 with the underlying layer 12 and the thin film 14 formed on its surface is then taken up in the form of a roll by a feeding and taking-up device 22.
In the inorganic film formation, the substrate roll 42 which takes up the substrate B on which surface the underlying layer 12 has been formed then undergoes formation of the thin film 14 by a vacuum film forming device 30.
Feeding of the substrate B from the taking-up and feeding device 32 is performed in synchronized with taking-up of the laminate 10 in the feeding and taking-up device 22, and the film formation of the thin film 14 on the substrate B is continuously performed while the long-length substrate B being conveyed in a longitudinal direction in a predetermined conveyance path.
In the C zone, the thin film 14 is formed on the surface of the substrate B (i.e. the surface of the underlying layer 12) using a vacuum film forming method, by a vacuum film forming device 30. When the vacuum film forming device 30 employs film formation by sputtering, plasma CVD or the like, a high-frequency power source, etc. is further provided in the C zone. A drum 29 in the C zone rotates around a center axis in a counterclockwise direction in the figure.
Also, in the case where film formation is performed by sputtering, plasma CVD or the like, the drum 29 may be grounded so as to function as a counter-electrode, or may be connected to a high-frequency power source.
The vacuum film forming device 30 is a device for forming the thin film (inorganic film) 14 on a surface of the substrate B (more specifically, on a surface of the underlying layer 12) by a vacuum film forming method. In this embodiment, here, the forming method of the inorganic film 14 is not particularly limited, and all conventionally known vacuum film forming methods (vapor-phase deposition methods), such as CVD, plasma CVD, sputtering, vacuum evaporation, and ion-plating may be employed.
The substrate B (i.e., a laminate) with the inorganic film 14 formed on its surface by the vacuum film forming device 30 while being supported and conveyed by the drum 29 is guided to a predetermined path by guide rollers 27 so as to pass through the B zone, and conveyed to the A zone to be taken up in the form of a roll by the feeding and taking-up device 22.
Note that in the film formation of the thin film (inorganic film) 14, an ultraviolet irradiation device 28, a drying device 26 and a coating device 24 are not used.
A laminate roll 40A which is taken up in the form of a roll can be subjected to film formation of an underlying layer and a thin film, in a similar manner as described above, or can be taken out from the laminate production apparatus 20 of the embodiment to put in use for a subsequent step.
In addition, the guide rollers 27 are preferably cylindrical rollers with a smooth surface. It is preferable that a plurality of cylindrical rollers with a smooth surface be set up so that the laminate is conveyed with a rear surface of a film-formed surface (surface on which the film has been formed) being contact with the plurality of cylindrical rollers with a smooth surface and with the film-formed surface facing downward to the ground. In other words, as illustrated in
As described above, the laminate production apparatus according to the embodiment of the present invention comprises: an A zone comprising a feeding and taking-up device which feeds a long-length substrate from a substrate roll and which takes up a laminate in which an underlying layer and a thin film are formed over the long-length substrate, and a coating device which applies a coating liquid containing a radiation curable monomer or oligomer onto the substrate to form a coated film; a B zone comprising a drying device which heat-treats the coated film; and a C zone comprising a ultraviolet irradiation device which cures the coated film which has been heated by ultraviolet radiation to form the underlying layer, a vacuum film forming device which forms a thin film on an underlying layer by a vacuum film forming method, and a taking-up and feeding device which takes up and feeds the long-length substrate on which surface the underlying layer has been formed. Therefore, the underlying layer and the thin film can be formed in a continuous operation in the production apparatus. Thus, the present embodiment can provide a laminate production apparatus capable of preventing dust from attaching to the substrate during transfer of the substrate.
It is preferable that the underlying layer (organic film) 12 has a high degree of smoothness and a high degree of film hardness. The smoothness of the surface of the underlying layer 12 is preferably, as an average surface roughness (Ra) per 10 μm square, 10 nm or less, more preferably 2 nm or less.
The film hardness of the underlying layer (organic film) 12 preferably is a certain degree or higher. The film hardness of the underlying layer 12 is preferably, as an indentation hardness measured by nanoindentation method, 100 N/mm2 or higher, more preferably 200 N/mm2 or higher. According to pencil hardness specified by JIS (Japanese Industrial Standards), the underlying layer 12 preferably has a pencil hardness of HB or higher, more preferably has a pencil hardness of H or higher.
In the present embodiment, the substrate B over which the underlying layer 12 and the thin film 14 are formed is not particularly limited, and all various types of substrates (base films) utilized for various types of functional films such as gas barrier film, optical film, and protective film may be used, as long as it can be used for forming the after-mentioned underlying layer 12 and forming the thin film 14 by vacuum firm formation, for example, various types of resin films such as PET (polyethylene terephthalate) film, various types of metal sheets such as aluminum sheet.
Also, the substrate B may be those with various films, such as a protective film, and an adhesive film, formed on a surface thereof.
The coated film forming the underlying layer (organic film) 12 is a film containing a radiation curable monomer or oligomer as the main component. Specifically, as a monomer or oligomer to be used herein, preferably, it has two or more ethylenically unsaturated double bonds and is a monomer or oligomer which is addition-polymerizable on exposure to light. As such monomers and oligomers, there may be exemplified compounds each having at least one addition-polymerizable ethylenically unsaturated group in its molecule and having a boiling point of 100° C. or higher at normal pressure. Specific examples thereof include monofunctional acrylates and monofunctional methacrylates such as polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, and phenoxyethyl(meth)acrylate; polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, trimethylolethane triacrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane diacrylate, neopentyl glycol di(meth)acrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, hexanediol di(meth)acrylate, trimethylolpropane tri(acryloyloxypropyl)ether, tri(acryloyloxyethyl) isocyanurate, tri(acryloyloxyethyl) cyanurate, and glycerin tri(meth)acrylate; and polyfunctional acrylates and polyfunctional methacrylates such as compounds obtained by adding ethylene oxide or propylene oxide to polyfunctional alcohol (e.g. trimethylolpropane, glycerin, etc.) and then (meth)acrylating the resulting product.
Further, as such monomers and oligomers, there may be exemplified, for example, polyfunctional acrylates and methacrylates such as urethane acrylates described in Japanese Examined Application Publication Nos. 48-41708 and 50-6034, and Japanese Patent Application Laid-Open No. 51-37193; polyester acrylates described in Japanese Patent Application Laid-Open No. 48-64183 and Japanese Examined Application Publication Nos. 49-43191 and 52-30490; and epoxy acrylates which are reaction products between epoxy resin and (meth)acrylic acid.
Among these, preferred are trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and dipentaerythritol penta(meth)acrylate.
Besides those described above, there may also be exemplified “polymerizable compound(s) B” described in Japanese Patent Application Laid-Open No. 11-133600 as suitable examples.
As a photopolymerization initiator or photopolymerization initiating system to be used herein, there may be exemplified vicinal polyketaldonyl compounds as disclosed in U.S. Pat. No. 2,367,660, acyloin ether compounds as disclosed in U.S. Pat. No. 2,448,828, aromatic acyloin compounds which are substituted with a hydrocarbon group at the α-position as disclosed in U.S. Pat. No. 2,722,512, polynuclear quinone compounds as disclosed in U.S. Pat. Nos. 3,046,127 and 2,951,758, a combination of triaryl imidazole dimer and p-aminoketone as disclosed in U.S. Pat. No. 3,549,367, benzothiazole compounds and trihalomethyl-s-triazine compounds as disclosed in Japanese Examined Application Publication No. 51-48516, trihalomethyl-triazine compounds as disclosed in U.S. Pat. No. 4,239,850, trihalomethyl oxadiazole compounds as disclosed in U.S. Pat. No. 4,212,976. Among these, trihalomethyl-s-triazine, trihalomethyl oxadiazole and triaryl imidazole dimer are particularly preferable.
Besides those described above, there may also be exemplified “polymerization initiator(s) C” described in Japanese Patent Application Laid-Open No. 11-133600 as suitable examples. The amount of the photopolymerization initiator relative to the total solid content of the coating liquid is preferably 0.01% by mass to 20% by mass, more preferably 0.5% by mass to 10% by mass. In the exposure to radiation for polymerization of a liquid crystalline compound, it is preferable to use ultraviolet rays. The amount of radiation energy is preferably 20 mJ/cm2 to 50 mJ/cm2, more preferably 100 mJ/cm2 to 2,000 mJ/cm2. In order to accelerate the photopolymerization reaction, the coating liquid may be exposed to radiation under application of heat.
As a film forming method of the underlying layer 12, conventional solution coating methods are exemplified. Employable solution coating methods are dip coating method, air-knife coating method, curtain coating method, roller coating method, wire bar coating method, gravure coating method, slide coating method or an extrusion coating method using a hopper as described in U.S. Pat. No. 2,681,294.
Note that the acrylate and methacrylate are liable to undergo polymerization inhibition due to oxygen in the air. Thus, in the present embodiment, when they are used for the organic film 12, it is preferable to lower the oxygen concentration or oxygen partial pressure in polymerization. In the case where the oxygen concentration in polymerization is lowered by a nitrogen substitution method, the oxygen concentration is preferably 2% or lower, more preferably 0.5% or lower. In the case where the oxygen partial pressure in polymerization is lowered by a pressure reduction method, the total pressure is preferably 1,000 Pa or lower, more preferably 100 Pa or lower. Especially preferred is UV polymerization with energy irradiation of 2 J/cm2 or higher under a reduced pressure of 100 Pa or lower.
In the present embodiment, the rate of polymerization of the monomer is preferably 80% or more, more preferably 85% or more, still more preferably 90% or more. The term “rate of polymerization” herein means the rate of reacted polymerizable groups to the total polymerizable groups (for example, in the case of acrylate or methacrylate, acryloyl groups and methacryloyl groups) in the monomer mixture.
When as a laminated film, a protective film is produced for use in various types of devices or apparatuses such as an organic EL display and a liquid crystal display, a silicon oxide film or the like may be formed as the thin film 14.
Furthermore, when as a laminated film, a light reflection-preventive film, a light reflective film or an optical film for use in various types of filters and the like is produced, a film composed of a material having or exhibiting intended optical properties may be formed as the thin film 14.
Among a variety of films, the present embodiment is most suitably utilized in particular for production of gas barrier film because it is possible to form the thin film 14 which is superior in terms of gas barrier properties because of superior surface smoothness of the organic film 12.
Note that the thin film 14 is not limited to a single layer, and may be a multilayer. When the thin film is formed as a multilayer, each individual layers may be identical to or different from each other.
Hereinabove, a laminate production apparatus according to the present embodiment has been described in detail, however, the present invention is not limited to the embodiments described above. The present invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. For instance, the above-mentioned embodiments describes the case where the coating liquid contains a radiation curable monomer or oligomer, however, an underlying layer according to the present invention is not limited to the case where the underlying layer coating liquid contains a radiation curable monomer or oligomer, and the underlying layer coating liquid may contain a thermosetting resin. In this case, the ultraviolet irradiation device 28 in the laminate production apparatus 20 illustrated in
| Number | Date | Country | Kind |
|---|---|---|---|
| 2008-238862 | Sep 2008 | JP | national |
