Manufacturing method of laminate film roll

Abstract

To provide a manufacturing method of a laminate film roll, which can efficiently suppress adhesion of dust with a simple operation without impairing a quality of a film.SOLUTION: There is provided a manufacturing method of a laminate film roll, wherein the laminate film roll is a roll of a laminate film in which a resin film and a protective film are laminated together. The manufacturing method includes a step of passing the resin film and the protective film in a superimposed state between a pair of sticking rolls and applying pressure to the resin film and the protective film with the sticking rolls. At least one of the pair of sticking rolls is a silicone rubber roll having a peripheral surface layer made of silicone rubber. The pressing step includes removing dust on a surface of the resin film, the protective film, or both thereof by the silicone rubber roll.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a laminate film roll.

Background Art

[0002] Generally, resin films used for industrial applications such as optical films need to protect their surfaces during operations such as transportation and storage. For such protection, it is widely practiced to laminate a protective film on the resin film to form a laminate film. Further, it is also widely practiced to wind a long laminate film of such a type around a winding core to form a laminate film roll. In particular, when forming a film into a film roll, the films are stacked on top of each other in the roll, and undesired physical effects such as displacement between the films and compression of the films occur in the roll. Therefore, it is particularly important to protect the surface of the film from such effects, and thus it is particularly important to laminate a protective film on the resin film for protection.

[0003] When laminating a protective film on a long resin film and winding it up to form a laminate film roll, it is common to continuously perform the operations of unwinding the long resin film and the long protective film, aligning their longitudinal directions, laminating them to form a laminate film, and further winding it into a roll in a conveyance path.

[0004] When continuously laminating a protective film on a long resin film, it is generally performed by passing them between a pair of laminating rolls and applying pressure. However, in these pressurizing steps and the steps before and after them, there may occur undesired phenomena such as dust adhering to the surface of the film, which degrades the quality of the resulting laminate film and its roll. Here, "dust" means all foreign matters that should be avoided from adhering to the film in the manufacture of the film and the film roll.

[0005] Specifically, if a film is transported and wound with dust attached thereto, the dust will press against the film during the transport process and in the wound roll, causing dents and impairing the quality of the film. In particular, if dust is caught in the film roll, dents will occur not only in the film where the dust is attached, but also on the core side and outside of the film, causing a defect called periodic dents, which will significantly impair the quality of the film roll.

[0006] In order to reduce the occurrence of such a phenomenon, it is known to provide a dust removal roll in combination with the laminating roll to remove dust from the peripheral surface of the laminating roll (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2013-109335 A Summary of the Invention [Problem to be solved by the invention]

[0008] In the case of removing dust during lamination, not only dust accumulated on the peripheral surface of the lamination roll, but also dust adhering to the film at other points in the film transport path can cause a deterioration in the quality of the laminated film and its roll. In particular, in the process of unwinding the resin film and the protective film and the process immediately downstream thereof, dust often enters the working space from the outside. Therefore, dust adhering to the film at a point located upstream of the transport path rather than the lamination process can be a major problem. In particular, while sufficient attention is paid to the adhesion of dust on the lamination surface (the surface of the resin film that contacts the protective film and the surface of the protective film that contacts the resin film) in the manufacturing process, it is required to efficiently remove dust from the surface opposite to the lamination surface by a simple operation. If a large number of dust removal rolls are provided for dust removal, the risk of deformation occurring on the film surface due to contact between the film and the dust removal roll increases.

[0009] Accordingly, an object of the present invention is to provide a method for manufacturing a laminated film roll that can efficiently suppress the adhesion of dust to the surface on the side opposite to the bonding surface at a location upstream of the bonding step in the conveyance path during the manufacture of the laminated film roll with a simple operation without deteriorating the quality of the film. **Means for Solving the Problems**

[0010] The inventor has conducted studies to solve the above-described problems. As a result, the inventor has conceived to solve the above problems by daringly adopting a silicone rubber roll to which dust is likely to adhere for the bonding roll itself, and has completed the present invention. That is, according to the present invention, the following are provided.

[0011] (1) A method for manufacturing a laminated film roll, wherein the laminated film roll is a roll of a laminated film obtained by laminating a resin film and a protective film, and the manufacturing method includes a step of passing the resin film and the protective film in a stacked state between a pair of bonding rolls and applying pressure to the resin film and the protective film with the bonding rolls, wherein at least one of the pair of bonding rolls is a silicone rubber roll whose peripheral surface layer is made of silicone rubber, and the step of applying pressure includes removing dust on the surface of the resin film, the protective film, or both of them with the silicone rubber roll. (2) The method for manufacturing a laminated film roll according to (1), further including removing dust adhering to the surface of the bonding roll by a dust removal roll provided in contact with one or both of the pair of bonding rolls. (3) The method for manufacturing a laminated film roll according to (1) or (2), wherein the resin film is a film of a cycloolefin resin. The method for manufacturing a laminate film roll according to any one of (1) to (3), wherein the protective film is a polyethylene resin film. The method for manufacturing a laminate film roll according to any one of (1) to (4), wherein the laminating roll provided on the protective film surface side is the silicone rubber roll. The method for manufacturing a laminate film roll according to any one of (2) to (5), wherein the dust removing roll is provided in contact with the silicone rubber roll, and the removal is performed on the silicone rubber roll. [[Effect of the Invention]]

[0012] According to the present invention, in the manufacture of a laminate film roll, adhesion of dust to the surface on the side opposite to the bonding surface at a location upstream of the bonding step in the conveyance path can be efficiently suppressed by a simple operation without deteriorating the film quality, and a method for manufacturing a laminate film roll is provided. [[Brief Description of the Drawings]]

[0013]

Figure 1

[0014] Hereinafter, the present invention will be described in detail with reference to embodiments, exemplifications, etc. However, the present invention is not limited to the embodiments and exemplifications shown below, and can be arbitrarily modified and implemented without departing from the scope of the claims of the present invention and its equivalent scope.

[0015] In the following description, expressions such as “(meth)acryl” mean acrylic, methacrylic, or a combination thereof. For example, a (meth)acrylic polymer means an acrylic polymer (a polymer of acrylic acid, acrylic acid ester, etc.), a methacrylic polymer (a polymer of methacrylic acid, methacrylic acid ester, etc.), or a combination thereof.

[0016] In the following description, the "long film" refers to a film having a length of at least five times or more, preferably ten times or more, the width of the film, and specifically, a film having a length such that it can be wound up in a roll shape for storage or transportation.

[0017] (Method for manufacturing a laminated film roll: Pressing step) The laminated film roll manufactured by the manufacturing method of the present invention is a roll of a laminate obtained by laminating a resin film and a protective film. The manufacturing method of the present invention includes a step of passing a resin film and a protective film in a stacked state between a pair of laminating rolls and pressing the resin film and the protective film with the laminating rolls.

[0018] FIG. 1 is a side view schematically showing an example of a manufacturing apparatus used in the manufacturing method of the present invention and a manufacturing method using the same. In FIG. 1, the manufacturing apparatus 10 includes a pair of laminating rolls 210 including an upper laminating roll 211 and a lower laminating roll 212. In this example, the upper laminating roll 211 is a laminating roll on the resin film side, and the lower laminating roll 212 is a laminating roll on the protective film side.

[0019] In the manufacturing apparatus 10, a resin film 111 and a protective film 112 are conveyed in the directions of arrows A111 and A112, respectively, using an appropriate conveying device (not shown). These are guided between the laminating rolls 210 and pass through the pressing position 220. When passing through the pressing position 220, they are stacked, and further pressed by the laminating roll 220 in the stacked state to form a laminated film 120.

[0020] In the pressing operation, the bonding roll rotates along the film conveyance direction and can be biased in the direction of pressing the film. In the example of FIG. 1, the upper bonding roll 211 and the lower bonding roll 212 rotate in the directions of arrow A211 and arrow A212, respectively, and are biased in the directions of arrow A211p and A212p, respectively, by an appropriate mechanism (not shown) such as a biasing mechanism to the rotating shaft member, thereby achieving pressing on the film.

[0021] In the manufacturing method of the present invention, at least one of the pair of bonding rolls is a silicone rubber roll. A silicone rubber roll is a roll whose peripheral surface layer is made of silicone rubber. In the silicone rubber roll, the material constituting the portion inside such a peripheral surface is not particularly limited, and an appropriate material can be selected from various viewpoints such as strength, cost, and weight.

[0022] In the example of FIG. 1, among the upper bonding roll 211 and the lower bonding roll 212, the lower bonding roll 212 is a silicone rubber roll. That is, in the lower bonding roll 212, the layer constituting the peripheral surface 212s is a layer made of silicone rubber. However, the present invention is not limited thereto, and the upper bonding roll may be a silicone rubber roll, or both the upper bonding roll and the lower bonding roll may be silicone rubber rolls. In particular, it is preferable that the bonding roll provided on the protective film side is a silicone rubber roll, thereby performing dust removal on the protective film side.

[0023] In the manufacturing method of the present invention, the pressing step includes removing dust on the surface of the resin film, the protective film, or both of them by the silicone rubber roll. In the example of FIG. 1, the lower bonding roll 212 is a silicone rubber roll, and the dust adhering to the lower surface 112d of the protective film 112 can be easily removed by the adhesive force of the silicone on the peripheral surface layer of the lower bonding roll 212.

[0024] Since the bonding roll is a silicone rubber roll, it is possible to efficiently suppress the adhesion of dust to the surface opposite to the bonding surface at a location upstream of the bonding process in the conveyance path with a simple operation while suppressing a deterioration in the quality of the film. Specifically, as the bonding roll for pressurization, by daringly adopting a silicone rubber roll to which dust is likely to adhere, it is possible to daringly transfer the dust on the film to the silicone rubber roll during the pressurization process. As a result, dust removal from the film can be efficiently performed with a simple operation that also serves as the pressurization process. Further, since dust removal is performed in combination with the operation for bonding using the bonding roll necessary for bonding, there are fewer members that directly contact the film compared to the case where an additional dust removal roll that directly contacts the film is provided. As a result, it is possible to reduce the possibility that the quality of the film is impaired.

[0025] By performing such dust removal from the film, it is possible to efficiently suppress the adhesion of dust to the surface opposite to the bonding surface at a location upstream of the bonding process in the conveyance path with a simple operation. By suppressing the adhesion of dust, it is possible to effectively reduce the occurrence of defects such as periodic indentations in the resulting laminated film roll.

[0026] The manufacturing method of the present invention preferably further includes removing dust adhering to the surface of the bonding roll by a dust removal roll provided in contact with one or both of a pair of bonding rolls. By removing the dust by such a dust removal roll, it is possible to remove the dust adhering to the bonding roll and effectively measure the reverse transfer of dust from the bonding roll to the film. Further, compared to the case where the dust removal roll directly contacts the film separately from the bonding roll, since there is less risk of deformation of the film due to the dust removal roll, it is possible to reduce the possibility that the quality of the film is impaired.

[0027] In the example of FIG. 1, a dust removal roll 221 is provided in contact with the lower bonding roll 212. The dust removal roll 221 rotates in the direction of arrow A213 and contacts the peripheral surface 212s of the lower bonding roll 212, thereby removing the dust present on the peripheral surface 212s of the lower bonding roll. By continuously performing the dust removal process, a large amount of dust may accumulate on the peripheral surface of the dust removal roll 221, or the dust removal ability of the dust removal roll 221 may decrease. In that case, for example, by replacing the dust removal roll 221, the dust removal ability can be restored. Such replacement can be performed without stopping the manufacturing process of the laminate film roll, so efficient manufacturing can be carried out.

[0028] As the dust removal roll, a roll having a layer of a material with a higher ability to adhere dust than silicone rubber as the peripheral surface layer can be appropriately adopted. Examples of the material of the peripheral surface layer include adhesive materials such as acrylic-based and urethane-based adhesives. As the dust removal roll, various commercially available products can be used. Examples of such commercially available products include the polymer rubber dust removal rolls (RUS series, HSS series, LPS series, SRR series, etc.) manufactured by YanGo, the "Gapless TM ULT" (trade name), "Gapless TM SRR" (trade name), which are adhesive tape rolls for dust transfer manufactured by YanGo, and the "AMS adhesive sheet roll (product name) / ARSP precut adhesive sheet roll (trade name)" manufactured by YanGo, and the adhesive rolls manufactured by TEKNEK.

[0029] (Method for manufacturing a laminate film roll: Other processes) After the pressing step, further processing can be performed on the obtained laminate film to obtain a laminate film roll. Specifically, downstream of the pressing step, a step of winding the laminate film by a winding device can be performed to obtain a laminated film roll. Further, as an optional step, dust removal by an additional dust removal roll may be performed downstream of the pressing step and upstream of the winding step.

[0030] (Resin film) A resin film applicable to the manufacturing method of the present invention will be described. The "resin film" referred to in this application is a film used for industrial applications such as optical films. Therefore, it is necessary to protect the surface state, and it is a film that is required to be protected by a protective film.

[0031] The resin film is usually a long film. By using a long film, it becomes possible to efficiently manufacture a laminated film roll using a laminating roll. When the resin film is a long film, the width of the film is preferably 500 mm or more, more preferably 1000 mm or more, while preferably 2500 mm or less, more preferably 2000 mm or less. The thickness of the resin film is preferably 5 μm or more, more preferably 10 μm or more, while preferably 200 μm or less, more preferably 150 μm or less.

[0032] Examples of the material constituting the resin film include various thermoplastic resins. Examples of thermoplastic resins include resins containing various polymers. Such polymers include hydrocarbon polymers, (meth)acrylic polymers, and polyesters.

[0033] A hydrocarbon polymer refers to a polymer in which at least a part of the repeating unit of the polymer is a hydrocarbon group. The ratio of the hydrocarbon group, which is the repeating unit, in the hydrocarbon polymer can be appropriately selected according to the purpose of use, but is preferably 55% by weight or more, more preferably 70% by weight or more, and particularly preferably 90% by weight or more.

[0034] As the hydrocarbon polymer, an alicyclic structure-containing polymer is preferred. An alicyclic structure-containing polymer is a polymer having an alicyclic structure in the repeating unit of the polymer, and may be either a polymer having an alicyclic structure in the main chain or a polymer having an alicyclic structure in the side chain. Among them, from the viewpoints of the mechanical strength, heat resistance, etc. of the obtained resin film, a polymer containing an alicyclic structure in the main chain is preferred.

[0035] Examples of the alicyclic structure include a saturated alicyclic hydrocarbon (cycloalkane) structure, an unsaturated alicyclic hydrocarbon (cycloalkene, cycloalkyne) structure, etc. Among them, from the viewpoints of mechanical strength, heat resistance, etc., a cycloalkane structure and a cycloalkene structure are preferable, and among them, a cycloalkane structure is particularly preferable.

[0036] When the number of carbon atoms constituting the alicyclic structure is preferably 4 or more, more preferably 5 or more, per alicyclic structure, and preferably 30 or less, more preferably 20 or less, particularly preferably 15 or less, the mechanical strength, heat resistance, and film formability are highly balanced and suitable.

[0037] The ratio of the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer can be appropriately selected according to the purpose of use, but is preferably 55% by weight or more, more preferably 70% by weight or more, particularly preferably 90% by weight or more. When the ratio of the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer is within this range, it is preferable from the viewpoints of transparency and heat resistance of the resin film.

[0038] Examples of the alicyclic structure-containing polymer include norbornene-based polymers, monocyclic cyclic olefin-based polymers, cyclic conjugated diene-based polymers, vinyl alicyclic hydrocarbon-based polymers, and hydrides thereof. Among these, norbornene-based polymers can be preferably used because of their good transparency and formability.

[0039] Examples of the norbornene-based polymer include a ring-opening polymer of a monomer having a norbornene structure, a ring-opening copolymer of a monomer having a norbornene structure and another monomer, or a hydride thereof; an addition polymer of a monomer having a norbornene structure, an addition copolymer of a monomer having a norbornene structure and another monomer, or a hydride thereof; and the like. Among these, a hydride of a ring-opening (co)polymer of a monomer having a norbornene structure can be particularly preferably used from the viewpoints of transparency, moldability, heat resistance, low hygroscopicity, dimensional stability, light weight, etc. The “(co)polymer” refers to a polymer and a copolymer.

[0040] Examples of the monomer having a norbornene structure include bicyclo[2.2.1]hept-2-ene (common name: norbornene), tricyclo[4.3.0.1 2,5 deca-3,7-diene (common name: dicyclopentadiene), 7,8-benzotricyclo[4.3.0.1 2,5 deca-3-ene (common name: methanotetrahydrofluorene), tetracyclo[4.4.0.1 2,5 .1 7,10 dodeca-3-ene (common name: tetracyclododecene), and derivatives of these compounds (for example, those having a substituent on the ring). Here, examples of the substituent include an alkyl group, an alkylene group, a polar group, etc. Further, these substituents may be the same or different, and a plurality of them may be bonded to the ring. The monomer having a norbornene structure may be used alone or in combination of two or more in any ratio.

[0041] Examples of the type of the polar group include a heteroatom or an atomic group having a heteroatom. Examples of the heteroatom include an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, a halogen atom, etc. Specific examples of the polar group include a carboxyl group, a carbonyloxycarbonyl group, an epoxy group, a hydroxyl group, an oxy group, an ester group, a silanol group, a silyl group, an amino group, a nitrile group, a sulfonic acid group, etc.

[0042] Examples of monomers having a norbornene structure and other monomers capable of ring-opening copolymerization include monocyclic olefins such as cyclohexene, cycloheptene, cyclooctene and their derivatives; cyclic conjugated dienes such as cyclohexadiene, cycloheptadiene and their derivatives; and the like. Other monomers capable of ring-opening copolymerization with the monomer having a norbornene structure may be used alone or in combination of two or more in any ratio.

[0043] The ring-opening polymer of the monomer having a norbornene structure and the ring-opening copolymer of the monomer having a norbornene structure and other monomers capable of copolymerization can be obtained, for example, by polymerizing or copolymerizing the monomer in the presence of a known ring-opening polymerization catalyst.

[0044] Examples of other monomers capable of addition copolymerization with the monomer having a norbornene structure include α-olefins having 2 to 20 carbon atoms such as ethylene, propylene, 1-butene and their derivatives; cycloolefins such as cyclobutene, cyclopentene, cyclohexene and their derivatives; non-conjugated dienes such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene; and the like. Among these, α-olefins are preferred, and ethylene is more preferred. Other monomers capable of addition copolymerization with the monomer having a norbornene structure may be used alone or in combination of two or more in any ratio.

[0045] The addition polymer of the monomer having a norbornene structure and the addition copolymer of the monomer having a norbornene structure and other monomers capable of copolymerization can be obtained, for example, by polymerizing or copolymerizing the monomer in the presence of a known addition polymerization catalyst.

[0046] Examples of the monocyclic cyclic olefin polymer include addition polymers of cyclic olefin monomers having a monocyclic structure such as cyclohexene, cycloheptene, cyclooctene and the like.

[0047] Examples of the cyclic conjugated diene polymer include polymers obtained by subjecting addition polymers of conjugated diene monomers such as 1,3-butadiene, isoprene, and chloroprene to a cyclization reaction; 1,2- or 1,4-addition polymers of cyclic conjugated diene monomers such as cyclopentadiene and cyclohexadiene; and hydrides thereof.

[0048] Examples of the vinyl alicyclic hydrocarbon polymer include polymers of vinyl alicyclic hydrocarbon monomers such as vinylcyclohexene and vinylcyclohexane and hydrides thereof; hydrides obtained by hydrogenating aromatic ring moieties contained in polymers obtained by polymerizing vinyl aromatic hydrocarbon monomers such as styrene and α-methylstyrene; hydrides of aromatic rings of copolymers such as random copolymers or block copolymers of vinyl alicyclic hydrocarbon monomers or vinyl aromatic hydrocarbon monomers and other monomers copolymerizable with these vinyl aromatic hydrocarbon monomers. Examples of the block copolymer include diblock copolymers, triblock copolymers, or multi-block copolymers having three or more blocks, and gradient block copolymers.

[0049] The molecular weight of the hydrocarbon polymer is appropriately selected according to the intended use, but is usually 10,000 or more, preferably 15,000 or more, more preferably 20,000 or more, and usually 100,000 or less, preferably 80,000 or less, more preferably 50,000 or less, in terms of weight average molecular weight (Mw) in terms of polyisoprene or polystyrene measured by gel permeation chromatography using cyclohexane as a solvent (however, toluene may be used if the sample is insoluble in cyclohexane). When the weight average molecular weight is in such a range, the mechanical strength and moldability of the film are highly balanced and suitable.

[0050] The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the hydrocarbon polymer is usually 1.2 or more, preferably 1.5 or more, more preferably 1.8 or more, and is usually 3.5 or less, preferably 3.0 or less, more preferably 2.7 or less. When the molecular weight distribution of the hydrocarbon polymer exceeds 3.5, the low molecular weight components increase, so the components with a short relaxation time increase. Even for films having the same in-plane retardation Re, it is presumed that the relaxation during high-temperature exposure becomes large in a short time, and the stability of the film may decrease. On the other hand, those with a molecular weight distribution below 1.2 may lead to a decrease in the productivity of the hydrocarbon polymer and an increase in cost.

[0051] The glass transition temperature of the hydrocarbon polymer can be appropriately selected according to the intended use, but is preferably 130 °C or higher, more preferably 135 °C or higher, and is preferably 150 °C or lower, more preferably 145 °C or lower. If the glass transition temperature is below 130 °C, the durability at high temperatures may deteriorate. Those above 150 °C have improved durability but may be difficult to process normally.

[0052] The thermoplastic resin constituting the resin film may contain any other components in addition to polymers such as polymers containing an alicyclic structure, as long as the effects of the present invention are not significantly impaired. Examples of the optional components include additives such as colorants such as pigments and dyes; fluorescent brighteners; dispersants; heat stabilizers; light stabilizers; ultraviolet absorbers; antistatic agents; antioxidants; lubricants; etc. Note that the optional components may be used alone or in combination of two or more in any ratio. However, the thermoplastic resin constituting the resin film preferably contains polymers such as polymers containing an alicyclic structure, generally in an amount of about 50% to 100%, or about 70% to 100%.

[0053] The resin film can be obtained by molding a resin by a known film molding method. Examples of the film molding method include, for example, a casting molding method, an extrusion molding method, an inflation molding method, etc. Among them, the melt extrusion method that does not use a solvent is preferable from the viewpoints of efficiently reducing the amount of residual volatile components, the global environment and the working environment, and excellent manufacturing efficiency. Examples of the melt extrusion method include an inflation method using a die, but a method using a T-die is preferable in terms of excellent productivity and thickness accuracy. The obtained film can be used as it is as the resin film to be used in the manufacturing method of the present invention, or may be subjected to a treatment such as stretching as necessary and then used as a film having optical anisotropy. Further, an arbitrary layer such as a lubricating layer or an antistatic layer may be formed on the surface of the obtained film and used.

[0054] (Protective film) The protective film that can be used in the manufacturing method of the present invention will be described. The "protective film" referred to in the present application is a film other than the "resin film" described above, and is a film that is adhered to the resin film to protect the surface of the resin film. As the protective film, a film called a masking film that can be detachably adhered to the resin film can be used.

[0055] As the masking film, a film made of a resin other than the resin constituting the resin film is used. In particular, the masking film is preferably formed of a resin having excellent transparency, mechanical strength, thermal stability, and moisture shielding properties. Examples of such resins include polyethylene resins; cellulose acetate resins such as triacetyl cellulose; polyester resins such as polyethylene terephthalate; polyethersulfone resins; polycarbonate resins; polyamide resins; polyimide resins; chain polyolefin resins; acrylic resins; methacrylic resins, etc. These resins may be used alone, or two or more kinds may be used in combination at an arbitrary ratio.

[0056] The thickness of the masking film is arbitrary, but is usually 5 μm or more, usually 500 μm or less, preferably 300 μm or less, and more preferably 150 μm or less.

[0057] As the masking film, commercially available products may be used. Examples of commercially available masking films include, as masking films mainly made of polyethylene (PE), products named "Force Field" manufactured by Tredegar Corporation (product numbers "FF1025 series", "FF1035 series", "PEARL series", etc.); products named "Toretec" manufactured by Toray Film Processing Co., Ltd. (series represented by product number "TR7332" and "A521 series", etc.); products named "Esperan" manufactured by Okura Industries Co., Ltd. (product numbers "KT series" and "PL series", etc.). Further, as a masking film mainly made of polyethylene terephthalate (PET), a product named "Master Tack" (product number "KB series", etc.) manufactured by Fujimori Kogyo Co., Ltd. can be mentioned.

[0058] (Use of the laminated film roll) From the laminated film roll obtained by the production method of the present invention, the laminated film can be unwound, and if necessary, the protective film can be peeled off from the laminated film, and the obtained resin film can be used for any purpose. The resin film can be used for various applications that require good film surface properties. In particular, it can be suitably used for applications of optical films such as retardation films and polarizer protective films.

Examples

[0059] Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to the examples shown below, and can be arbitrarily modified and implemented without departing from the scope of the claims of the present invention and its equivalent scope. Further, in the following description, "parts" and "%" representing amounts are based on weight unless otherwise specified. The operations described below were performed in an environment of normal temperature and pressure unless otherwise specified.

[0060] (Evaluation method) (Evaluation of periodic indentations) The laminate film was unwound from the laminate film rolls obtained in the examples and comparative examples, and two rectangular samples with a full width × length of 1 m were cut out. The protective film was peeled off from one of the cut-out samples to obtain a film for inspection. This inspection film was visually observed under the reflection of light from a three-wavelength fluorescent lamp to detect indentations. When indentations were detected, the remaining one sample was also inspected in the same manner to check whether indentations occurred at the same positions along the same line in the longitudinal direction of the film (the longitudinal direction when it was in a long shape) at the same period as the roll period of the film roll. When indentations occurred periodically at the same positions in the film width direction, it was determined that "periodic indentations" occurred in one row.

[0061] In one sample, if no periodic indentations occurred, it was determined as "good"; if the number of occurrences of periodic indentations was 2 rows or less, it was determined as "acceptable"; if it was 3 rows or more, it was determined as "unacceptable".

[0062] (Production Example 1: Unstretched resin film 30 μm) Pellets of a resin containing a norbornene-based polymer ("Zeonex": glass transition temperature 126°C, manufactured by Nippon Zeon Co., Ltd.) were dried at 100°C for 5 hours. These pellets were supplied to an extruder, melted in the extruder, passed through a polymer pipe and a polymer filter, and extruded in a sheet form onto a casting drum from a T-die. The extruded resin was cooled and cured on the casting drum. As a result, an unstretched film with a thickness of 30 μm and in a long shape was obtained.

[0063] (Production Example 2: Unstretched resin film 60 μm) The same operations as in Production Example 1 were performed except that the size of the opening of the T-die was changed, and an unstretched film with a thickness of 60 μm and in a long shape was obtained.

[0064] (Production Example 3: Transversely stretched resin film) The unstretched film obtained in Production Example 2 was continuously supplied to a tenter stretching machine. The unstretched film was stretched horizontally by the tenter stretching machine to obtain a long stretched film. In this stretching, the stretching angle formed by the stretching direction with respect to the longitudinal direction of the unstretched film was 90°, the stretching temperature was 135 °C, and the stretching ratio was 2.0 times. The orientation angle of the obtained stretched film was 90° with respect to the longitudinal direction, the in-plane retardation Re was 120 nm, and the thickness was 30 μm.

[0065] (Production Example 4: Obliquely Stretched Resin Film) The unstretched film obtained in Production Example 2 was continuously supplied to a tenter stretching machine. The unstretched film was stretched obliquely by the tenter stretching machine to obtain a long stretched film. In this stretching, the stretching angle formed by the stretching direction with respect to the longitudinal direction of the unstretched film was 45°, the stretching temperature was 143 °C, and the stretching ratio was 1.5 times. The orientation angle of the obtained stretched film was 45° with respect to the longitudinal direction, the in-plane retardation Re was 120 nm, and the thickness was 40 μm.

[0066] (Production Example 5: Longitudinally Stretched Resin Film) The unstretched film obtained in Production Example 2 was continuously supplied to a roll stretching machine. The unstretched film was subjected to free uniaxial stretching by the roll stretching machine to obtain a long stretched film. In this stretching, the stretching angle formed by the stretching direction with respect to the longitudinal direction of the unstretched film was 0°, the stretching temperature was 140 °C, and the stretching ratio was 1.4 times. The orientation angle of the obtained stretched film was 0° with respect to the longitudinal direction, the in-plane retardation Re was 120 nm, and the thickness was 50 μm.

[0067] (Example 1) Using the manufacturing apparatus 10 schematically shown in FIG. 1, a laminated film roll was manufactured. In the manufacturing apparatus 10, as the upper laminating roll 211 and the lower laminating roll 212, a urethane rubber roll and a silicone rubber roll were used, respectively. As the dust removing roll 221, a polymer rubber dust removing roll (manufactured by YanGo) was used. As the resin film 111, the unstretched resin film obtained in Production Example 1 was used. As the protective film 112, a long protective film (manufactured by Toray Film Processing Co., Ltd., "Toretec (registered trademark), polyethylene masking film, product number A521 series") was used.

[0068] Using a suitable conveying device (not shown), the resin film 111 and the protective film 112 were conveyed in the directions of arrows A111 and A112, respectively, guided between the laminating rolls 210, and passed through the pressing position 220. When passing through the pressing position 220, the resin film 111 and the protective film 112 were overlapped, and further pressed by the laminating roll 220 in the overlapped state to obtain a laminated film 120. The obtained laminated film 120 was wound by a winding device (not shown) to obtain a laminated film roll.

[0069] The obtained laminated film roll was evaluated for periodic indentations.

[0070] (Example 2) Except for the following changes, the same operations as in Example 1 were performed to obtain a laminated film roll and evaluate it. · As the upper laminating roll 211, a metal roll was used instead of the urethane rubber roll. · As the resin film 111, the horizontally stretched resin film obtained in Production Example 3 was used instead of the unstretched resin film obtained in Production Example 1. · As the protective film 112, "Force Field (registered trademark)" (polyethylene masking film, product number PEARL series) manufactured by Tredegar was used.

[0071] (Example 3) Except for the following changes, the same operations as in Example 1 were performed to obtain a laminated film roll and evaluate it. · As the resin film 111, instead of the unstretched resin film obtained in Production Example 1, the obliquely stretched resin film obtained in Production Example 4 was used. · As the protective film 112, “Master Tack (registered trademark)” (polyethylene terephthalate masking film, product number KB series) manufactured by Fujimori Kogyo Co., Ltd. was used.

[0072] (Example 4) Except for the following changes, the same operations as in Example 1 were performed to obtain a laminated film roll and evaluate it. · As the upper laminating roll 211, instead of the urethane rubber roll, a metal roll was used. · As the resin film 111, instead of the unstretched resin film obtained in Production Example 1, the longitudinally stretched resin film obtained in Production Example 5 was used. · As the protective film 112, “Esperan (registered trademark)” (polyethylene masking film, product number PL series) manufactured by Okura Kogyo Co., Ltd. was used.

[0073] (Example 5) Except for the following changes, the same operations as in Example 1 were performed to obtain a laminated film roll and evaluate it. · The dust removal roll 221 was not used.

[0074] (Comparative Example 1) Except for the following changes, the same operations as in Example 1 were performed to obtain a laminated film roll and evaluate it. · As the upper laminating roll 211, instead of the urethane rubber roll, a metal roll was used. · As the lower laminating roll 212, instead of the silicone rubber roll, a urethane rubber roll was used. · The dust removal roll 221 was not used.

[0075] (Comparative Example 2) Except for the following changes, the same operations as in Example 1 were performed to obtain a laminated film roll and evaluate it. · As the upper laminating roll 211, instead of the urethane rubber roll, a metal roll was used. · As the lower bonding roll 212, a urethane rubber roll was used instead of a silicone rubber roll. · As the protective film 112, “Force Field (registered trademark)” manufactured by Tredegar Corporation (polyethylene masking film, product number FF-1025 series) was used.

[0076] (Comparative Example 3) Except for the following changes, the same operations as in Example 1 were performed to obtain a laminated film roll and evaluate it. · As the lower bonding roll 212, a urethane rubber roll was used instead of a silicone rubber roll. · The dust removal roll 221 was not used. · As the resin film 111, instead of the unstretched resin film obtained in Production Example 1, the obliquely stretched resin film obtained in Production Example 4 was used. · As the protective film 112, “Master Tack (registered trademark)” manufactured by Fujimori Kogyo Co., Ltd. (polyethylene terephthalate masking film, product number KB series) was used.

[0077] The outlines of the operations of the examples and comparative examples and the evaluation results are shown in Table 1.

[0078]

Table 1

[0079] As is clear from the results of the examples and comparative examples, in the examples where the laminated film roll was manufactured by the manufacturing method that satisfied the predetermined conditions defined in the present application, favorable results with fewer periodic indentations were obtained compared to the comparative examples. In particular, in Examples 1 to 4 where the dust removal roll was also used, the suppression of periodic indentations could be performed particularly well.

Explanation of Signs

[0080] 10: Manufacturing apparatus 111: Resin film 112: Protective film 112d: Lower surface of the protective film 210: Bonding roll 211: Upper bonding roll 212: Lower bonding roll 212s: Peripheral surface of the lower bonding roll 220: Pressing position 221: Dust removal roll

Claims

1. A method for manufacturing a laminated film roll, wherein the laminated film roll is a roll of a laminated film obtained by laminating a resin film and a protective film, the manufacturing method comprises a step of passing the resin film and the protective film in a stacked state between a pair of laminating rolls and applying pressure to the resin film and the protective film with the laminating rolls, at least one of the pair of laminating rolls is a silicone rubber roll whose peripheral surface layer is made of silicone rubber, the step of applying pressure includes removing dust on the surface of the resin film, the protective film, or both of them with the silicone rubber roll, the method for manufacturing a laminated film roll.

2. The method for manufacturing a laminated film roll according to claim 1, further comprising removing dust adhering to the surface of the laminating roll by a dust removing roll provided in contact with one or both of the pair of laminating rolls.

3. The method for manufacturing a laminated film roll according to claim 1, wherein the resin film is a film of a cycloolefin resin.

4. The method for manufacturing a laminated film roll according to claim 1, wherein the protective film is a film of a polyethylene resin.

5. The method for manufacturing a laminated film roll according to claim 1, wherein the laminating roll provided on the protective film side is the silicone rubber roll.

6. The method for manufacturing a laminated film roll according to claim 2, wherein the dust removing roll is provided in contact with the silicone rubber roll and performs the removal with respect to the silicone rubber roll.

Images