Method for manufacturing film laminate

Abstract

The purpose of the invention is to provide a film layered body, production method therefor, and method for transferring an functional layer onto an object which make it possible to reduce the amount of waste, prevent problems during winding, and provide functional layers with few defects.　The invention provides an elongated film layered body 1 formed by layering a base material film 2 and a surface protection film 4, wherein both edge portions of the surface protection film 4 in the width direction have been knurled.

Description

[Technical field]

[0001] The present invention relates to a film laminate having a surface protective film laminated thereon, and more particularly to a film laminate that can effectively utilize the width direction of the film and reduce waste. [Background technology]

[0002] As a method for providing a functional layer having various functions on an object, a transfer method for transferring a functional layer formed on a base film is known, and in recent years, the transfer method has been used in many fields. Examples of the functional layer include a surface decoration layer such as a printed layer or a metal deposition layer, an optical functional layer such as an anti-glare layer, an anti-reflection layer, a polarizing layer, and a retardation layer, a thin film layer, a thin film substrate layer of a circuit such as a ceramic layer, a circuit layer, a catalyst layer such as a fuel cell, and a barrier layer.

[0003] In these fields, functional layers are required to be thinner and more precise, and accordingly, the surface of the release substrate film on which the functional layer is formed is also required to have high precision and smoothness.

[0004] Generally, these release substrate films are manufactured and used as long rolls. In order to stably wind the film into a roll, the surface of the film needs to have a certain degree of roughness, but the film to which the functional layer is transferred needs to have high smoothness, which can make winding difficult.

[0005] As a method for facilitating winding of a film and preventing misalignment during winding and surface damage, knurling applied to the widthwise edges of the film as shown in Patent Document 1 is known.

[0006] In addition, when a film having a retardation layer or a polarizing layer made of a liquid crystal compound on a base film is stored in a rolled state, extremely high pressure is applied to the film on the core side at parts where the thickness has increased slightly due to slight thickness unevenness in the film or at steps in the film at the beginning of winding, which may disrupt the orientation of the liquid crystal compound that constitutes the retardation layer or the polarizing layer. In order to prevent this, knurling is sometimes performed.

[0007] When providing a functional layer on a base film, particularly when providing a functional layer on a release base film, if the base film is knurled, the knurled portion may become an obstacle to processing processes such as coating, transfer, and vapor deposition, as well as transportation, so the knurled portion has been slit and removed before processing.

[0008] Furthermore, release substrate films provided with functional layers are often knurled before being wound up, and when multiple functional layers are provided, the knurled portions are repeatedly removed, which requires the preparation of release substrate films that are significantly wider than the width of the final product, and also results in a large amount of waste due to the slitting and removal of the knurled portions, which is not only economically disadvantageous but also undesirable in terms of environmental protection. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2011-248198 A Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention has been made in light of the above-mentioned problems. An object of the present invention is to provide a film laminate for transfer to provide a functional layer on an object, which reduces waste, prevents trouble during winding, and allows a functional layer with fewer defects to be provided, a method for producing the same, and a method for transferring a functional layer to an object. [Means for solving the problem]

[0011] The film laminate of the present invention, which has been able to achieve the above object, and the method for producing the same, and the method for transferring a functional layer to an object, are summarized as follows.

[0012] [1] A long film laminate in which a base film and a surface protective film are laminated, characterized in that knurling is applied to both widthwise ends of the surface protective film.

[0013] [2] The film laminate according to [1], wherein the base film is not subjected to knurling.

[0014] [3] The film laminate according to [1] or [2], wherein a functional layer is disposed between the base film and the surface protective film.

[0015] [4] The film laminate according to [3], wherein the base film is a release film and the functional layer is a transferable thin film optical element.

[0016] [5] The film laminate according to [4], wherein the thin film optical element is an oriented liquid crystal compound layer.

[0017] [6] A method for manufacturing a film laminate, comprising the steps of: preparing the film laminate described in [1]; peeling a surface protective film from a base film of the film laminate; providing a functional layer on the surface of the base film on which the surface protective film was laminated; and bonding a surface protective film to the surface on which the functional layer is provided.

[0018] [7] A method for transferring a functional layer, comprising the steps of: producing a film laminate by the manufacturing method described in [6]; peeling a surface protective film from the film laminate; bonding the functional layer surface of the film laminate to an object to be transferred; and peeling the base film from the object to be transferred. Effect of the Invention

[0019] By using the film laminate of the present invention, when providing a functional layer on an object, the amount of waste can be reduced and problems that occur during winding can be prevented, making it possible to provide a functional layer with fewer defects on the object. [Brief description of the drawings]

[0020] [Figure 1] 1 is a cross-sectional view of a film laminate according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view of the film laminate of FIG. 1 as viewed from the surface protection film side. [Diagram 3] 1 is a cross-sectional view of a substrate film according to one embodiment of the present invention. [Figure 4] FIG. 2 is a cross-sectional view of a substrate film according to another embodiment of the present invention. [Diagram 5] FIG. 2 is a cross-sectional view of a substrate film according to yet another embodiment of the present invention. [Figure 6] 2 illustrates a cross-sectional view of a film stack according to another embodiment of the present invention. [Figure 7] 1 is a cross-sectional view of a functional layer laminate film according to one embodiment of the present invention. [Figure 8] 3 shows a cross section of a functional layer laminate film according to another embodiment of the present invention. [Figure 9] 3 illustrates a cross-sectional view of a film laminate according to yet another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The present invention will be described below based on the embodiments with reference to the drawings, but the present invention is not limited to the following embodiments, and can be modified as long as it satisfies the purpose described above and below, and all of these are included in the technical scope of the present invention. In addition, hatching and component symbols may be omitted in each drawing for convenience, but in such cases, the specification and other drawings shall be referred to. Also, the dimensions of components in the drawings may differ from the actual dimensions.

[0022] A film laminate 1 according to an embodiment of the present invention will be described with reference to Figs. 1 to 6. Fig. 1 shows a cross-sectional view in the thickness direction of a film laminate 1 according to one embodiment of the present invention, and Fig. 2 shows a plan view of the film laminate 1 in Fig. 1 as viewed from the surface protective film 4 side. Fig. 3 shows a cross-sectional view in the thickness direction of a base film 2 according to one embodiment of the present invention, Fig. 4 shows a cross-sectional view in the thickness direction of a base film 2 according to another embodiment of the present invention, and Fig. 5 shows a cross-sectional view in the thickness direction of a base film 2 according to yet another embodiment of the present invention. Also, Fig. 6 shows a cross-sectional view in the thickness direction of a film laminate 1 according to another embodiment of the present invention.

[0023] The film laminate 1 is a long film in which a base film 2 and a surface protection film 4 are laminated, and knurling is applied to both ends of the surface protection film 4 in the width direction, and the surface protection film 4 has knurled portions 4b at both ends in the width direction.

[0024] The film laminate 1 has a longitudinal direction (MD) and a transverse direction (TD) perpendicular to the longitudinal direction, and the base film 2 and the surface protective film 4 have the same longitudinal direction (MD) and transverse direction (TD) as described above. In addition, the film formation direction when the film laminate 1, the base film 2, and the surface protective film 4 are formed coincides with the longitudinal direction (MD).

[0025] [Base film] The base film 2 serves as a base material for laminating the functional layer 3 described below, and preferably has a release surface 2a with releasability so that the functional layer 3 can be peeled off after being attached to an object.

[0026] The resin used for the base film 2 is not particularly limited as long as it can maintain the strength required for the base film, but among them, polyester, polycarbonate, polystyrene, polyamide, polypropylene, cyclic polyolefin, triacetyl cellulose, and polyfluoroethylene are preferred, and polyethylene terephthalate, cyclic polyolefin, and triacetyl cellulose are particularly preferred.

[0027] The base film 2 may be a single layer or a multi-layer structure. In the case of a multi-layer structure, it may be formed by co-extrusion. Examples of the multi-layer structure include the release surface 2a side layer 20A / back surface side layer 20B, the release surface 2a side layer 20A / intermediate layer 20C / release surface 2a side layer 20A, and the release surface 2a side layer 20A / intermediate layer 20C / back surface side layer 20B, as shown in Figs. 3 to 5. The release surface 2a side layer 20A has releasability, and the back surface side layer 20B does not have to have releasability. Here, having releasability means that when the functional layer 3 provided on the base film 2 is transferred to an object, the peel strength between the functional layer 3 and the base film 2 is such that the functional layer 3 is transferred without remaining on the base film 2. The peel strength between the functional layer 3 and the base film 2 varies depending on various conditions such as the adhesive strength between the functional layer 3 and the object, the film strength of the functional layer 3, and the surface strength of the object, but is preferably 10 N / 25 mm or less, and more preferably 8 N / 25 mm or less. The peel strength between the functional layer 3 and the base film 2 is preferably 0.05 N / 25 mm or more, but must exceed the peel strength between the surface protective film 4 and the functional layer 3, which will be described later.

[0028] The thickness of the base film 2 is preferably 5 μm or more, more preferably 7 μm or more, and is preferably 80 μm or less, more preferably 60 μm or less.

[0029] The base film 2 may be a stretched film or an unstretched film. In the case of a stretched film, it may be uniaxially stretched, weakly biaxially stretched (stretched in two axial directions, but weakly in one direction), or biaxially stretched.

[0030] As shown in FIG. 6, the base film 2 may have a release layer 20a on the base film base layer 20. However, if the base film 2 itself has low adhesion to the functional layer 3 and has sufficient releasability without providing the release layer 20a, the release layer 20a may not be provided. If the adhesion is too low, the adhesion may be adjusted by performing a corona treatment on the surface. The release layer 20a can be formed using a known release agent, and preferred examples include alkyd resin, amino resin, long-chain acrylic acrylate, silicone resin, and fluororesin. These can be appropriately selected according to the adhesion with the functional layer.

[0031] The base film 2 may be provided with an antistatic layer, an oligomer or monomer precipitation prevention layer, a surface smoothing layer, etc. The thickness of the release layer, antistatic layer, precipitation prevention layer, surface smoothing layer, etc. is preferably 10 μm or less, more preferably 7 μm or less. Also, it is preferably 0.1 μm or more, particularly preferably 0.3 μm or more. Unless otherwise specified, the base film 2 includes the release layer, antistatic layer, precipitation prevention layer, surface smoothing layer, etc.

[0032] The release surface 2a (surface of the release surface layer 20A) of the base film 2 is preferably smooth. In the present invention, the "release surface 2a" of the base film means the surface of the base film on which a functional layer to be transferred is intended to be provided. When an antistatic layer, a deposition prevention layer, a flattening coating layer, a release layer, or the like is provided, if a functional layer is provided thereon, the surfaces of these layers (surfaces in contact with the functional layer) are the "release surface 2a" of the base film.

[0033] The lower limit of the three-dimensional arithmetic mean roughness (SRa) of the release surface 2a of the base film 2 is preferably 1 nm, more preferably 2 nm. If it is less than the above, it may be difficult to achieve the numerical value in reality. The upper limit of the SRa of the release surface 2a of the base film 2 is preferably 30 nm, more preferably 25 nm, even more preferably 20 nm, particularly preferably 15 nm, and most preferably 10 nm.

[0034] The lower limit of the three-dimensional ten-point average roughness (SRz) of the release surface 2a of the base film 2 is preferably 5 nm, more preferably 10 nm, and even more preferably 13 nm. The upper limit of SRz of the release surface 2a of the base film 2 is preferably 200 nm, more preferably 150 nm, even more preferably 120 nm, particularly preferably 100 nm, and most preferably 80 nm.

[0035] The lower limit of the maximum height (SRy: maximum peak height SRp of the release surface + maximum valley depth SRv of the release surface) of the release surface 2a of the base film 2 is preferably 10 nm, more preferably 15 nm, and even more preferably 20 nm. The upper limit of SRy of the release surface 2a of the base film 2 is preferably 300 nm, more preferably 250 nm, even more preferably 150 nm, particularly preferably 120 nm, and most preferably 100 nm.

[0036] The base film 2 is industrially supplied in the form of a wound film roll. The lower limit of the roll width is preferably 300 mm, more preferably 500 mm, and even more preferably 600 mm. The upper limit of the roll width is preferably 5000 mm, more preferably 4000 mm, and even more preferably 3000 mm.

[0037] The lower limit of the roll length is preferably 100 m, more preferably 500 m, and even more preferably 1000 m. The upper limit of the roll length is preferably 100,000 m, more preferably 50,000 m, and even more preferably 30,000 m.

[0038] [Surface protection film] A surface protective film 4 is laminated to the release surface 2a of the base film 2, and the film is wound into a roll. Knurling is applied to the ends in the width direction of the surface protective film 4. By laminating the surface protective film 4, it is possible to prevent the release surface 2a of the base film 2 from being scratched, and by applying knurling to the surface protective film 4, it is possible to prevent wrinkles from occurring, making it easier to wind up, and also to prevent the film from shifting during storage, transportation, etc. in the wound state.

[0039] As shown in FIG. 6, the surface protective film 4 may have a surface protective film base layer 40 provided with an adhesive layer 40a.

[0040] Examples of the surface protection film substrate layer 40 include resin films and paper, with resin films being preferred. Suitable examples of resins used in the resin film include polyolefins, polyesters, polyamides, polyurethanes, and the like, with polyolefins being preferred being polypropylene and polyethylene, and polyesters being preferred being polyethylene terephthalate. These may be copolymerized to adjust various physical properties such as the flexibility of the film. The resin film may be an unstretched film or a stretched film. In the case of a stretched film, it may be uniaxially stretched or biaxially stretched.

[0041] The adhesive layer 40a of the surface protection film 4 can use conventional adhesives such as rubber-based, acrylic-based, and polyolefin-based adhesives. Examples of rubber-based adhesives include natural rubber, butadiene rubber, isoprene rubber, and styrene-based block copolymer elastomers such as SBS, SIS, SEBS, and SEPS. Examples of acrylic-based adhesives include crosslinked copolymers of methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Examples of crosslinking agents include isocyanate compounds, epoxy compounds, metal chelating agents, and compounds containing multiple double bonds.

[0042] Examples of polyolefin-based rubbers include ethylene-propylene rubbers such as EPM and EPDM, rubbers that use these as soft segments and polyethylene or polypropylene as hard segments, and blends of ethylene-propylene rubber with polyethylene or polypropylene.

[0043] These adhesives may contain various adhesion regulators and stabilizers, such as tackifiers, fatty acid esters, fatty acid bisamides, polyglycerin, silicone oil, and silicone resins.

[0044] The adhesive may be provided by coating the surface protective film substrate layer 40, or by co-extruding the substrate resin and the resin that will become the adhesive layer when forming the surface protective film substrate layer 40.

[0045] The peel strength of the surface protective film 4 is preferably 0.01 N / 25 mm or more, more preferably 0.03 N / 25 mm or more, and even more preferably 0.05 N / 25 mm or more. The peel strength is preferably 2.0 N / 25 mm or less, more preferably 1.5 N / 25 mm or less, even more preferably 1.0 N / 25 mm or less, particularly preferably 0.7 N / 25 mm or less, and most preferably 0.5 N / 25 mm or less. The adhesive strength of the surface protective film 4 is the adhesive strength when the surface protective film 4 is peeled from the film laminate 1 consisting of the base film 2 and the surface protective film 4, or the film laminate 1 having the functional layer 3 between the base film 2 and the surface protective film 4. The adhesive strength of the surface protective film 4 can be adjusted by the composition and thickness of the adhesive.

[0046] By setting the peel strength at the above level, problems such as inadvertent peeling of the surface protective film 4 are less likely to occur during the winding process, the unwinding process, the process of peeling the surface protective film 4 from the base film 2 and providing the base film 2 with the functional layer 3, and the process of peeling the surface protective film 4 from the base film 2 laminated with the functional layer 3 and attaching it to an object. Furthermore, by setting the peel strength at the above level or less, a high processing speed can be ensured in each process that requires peeling of the surface protective film 4, reducing problems such as the functional layer 3 being taken up by the surface protective film 4, and making it easier to perform stable processing.

[0047] The total thickness of the surface protective film 4 is preferably 5 μm or more, more preferably 10 μm or more, and is preferably 100 μm or less, more preferably 80 μm or less.

[0048] The thickness of the adhesive layer 40a is preferably 1 μm or more, more preferably 2 μm or more, and is preferably 50 μm or less, more preferably 30 μm or less. However, the thickness of the adhesive layer 40a is preferably 70% or less of the thickness of the surface protective film 4, more preferably 50% or less, and is preferably 5% or more, more preferably 10% or more.

[0049] [Knurl processing] The surface protection film 4 is knurled at both ends in the width direction, and the surface protection film 4 has knurled portions 4b at both ends in the width direction. The width of the knurled portions 4b is preferably 5 mm or more, more preferably 7 mm or more, and particularly preferably 10 mm or more. The width of the knurled portions 4b is preferably 50 mm or less, more preferably 40 mm or less, and particularly preferably 30 mm or less.

[0050] The knurling may be performed from the end in the width direction of the surface protection film 4, but is preferably performed with a gap of 2 mm or more inward from the end, and more preferably with a gap of 3 mm or more. The gap between the knurled portion 4b and the end of the surface protection film 4 is preferably 30 mm or less, more preferably 20 mm or less, and even more preferably 10 mm or less. By providing the gap, the knurling can be performed reliably.

[0051] The height of the knurling is preferably 0.5 μm or more, more preferably 1 μm or more, and even more preferably 1.5 μm or more. The height of the knurling is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 12 μm or less.

[0052] By setting the width, the distance from the outermost end, and the height of the knurled portion 4b within the above ranges, stable winding can be achieved and winding deviation can be effectively prevented. In addition, when the substrate film 2 is provided with an oriented liquid crystal compound layer 30 as the functional layer 3, the oriented state of the oriented liquid crystal compound layer 30 can be maintained.

[0053] Methods for performing knurling include (1) a method of passing a surface protection film 4 between a pair of knurls having a protrusion and a matching recess to give a wavy shape, (2) a method of passing a surface protection film 4 between a knurl having a protrusion and a flat knurl to provide a raised portion pushed aside by the protrusion around the recess, (3) a method of irradiating a laser to provide a raised portion around the recess, and (4) a method of providing a convex portion using a hot melt resin or an ultraviolet irradiated resin. In knurling using knurling, the knurling may be heated or the portion of the film to which the knurls are to be applied may be irradiated with infrared rays to make it easier to perform the knurling.

[0054] The shape of the convex and concave portions of the knurled surface may be any shape, such as a circle, an ellipse, a triangle, a square, a rhombus, a trapezoid, a pentagon, a hexagon, or a polygon having more than one side, or may be a combination of a plurality of these shapes.

[0055] The distance between adjacent convex portions or concave portions is preferably 100 μm or more, more preferably 200 μm or more, and is preferably 5 mm or less, and further preferably 3 mm or less, in terms of the closest distance between adjacent convex portions or concave portions.

[0056] The arrangement of the convex portions and concave portions may be aligned vertically and horizontally, or may be a staggered arrangement in which adjacent concave-convex arrangements are shifted by a half period, or a diagonal arrangement in which adjacent concave-convex arrangements are shifted by 1 / 3 or 1 / 4. The convex portions formed by knurling are preferably provided on the surface of the surface protection film 4 that is not bonded to the base film 2 or the functional layer 3.

[0057] The knurling may be performed in advance during the production of the surface protection film 4, or may be performed immediately before unrolling the surface protection film 4 that has not been knurled and bonding it to the base film 2. Alternatively, the knurling may be performed only on the surface protection film 4 in a state where the base film 2 and the surface protection film 4 are bonded together. In this case, the above methods (2), (3), and (4) are preferred.

[0058] It is preferable that knurling is not performed on the base film 2. By not performing knurling on the base film 2, the functional layer 3 can be provided on the base film 2 by effectively utilizing the entire width of the base film 2, thereby improving productivity and reducing the amount of waste.

[0059] The width of the surface protective film 4 is preferably in the range of −30 to +30 mm relative to the width of the base film 2, more preferably −20 to +20 mm, and particularly preferably −10 to +10 mm. Most preferably, the width of the surface protective film 4 is the same as the width of the base film 2.

[0060] In addition, it is preferable that the position of the knurling process on the surface protection film 4 be adjusted in accordance with the width of the base film 2 .

[0061] [Functional Layer] It is preferable that a functional layer 3 is disposed between the substrate film 2 and the surface protective film 4. The functional layer 3 will be described with reference to Fig. 7 and Fig. 8. Fig. 7 shows a cross-sectional view of a functional layer laminate film 5 according to one embodiment of the present invention, and Fig. 8 shows a cross-sectional view of a functional layer laminate film 5 according to another embodiment of the present invention.

[0062] A film laminate 1 consisting of a base film 2 and a surface protective film 4 wound into a roll is unwound and the surface protective film 4 is peeled off, and a functional layer 3 is provided on the surface of the base film 2 on which the surface protective film 4 was laminated, i.e., the release surface 2a, to obtain a functional layer laminate film 5 as shown in Figure 7.

[0063] Examples of the functional layer 3 include surface decoration layers such as printed layers and metal deposition layers, thin-film optical elements such as antiglare layers, antireflection layers, polarizing layers, and retardation layers, thin-film substrate layers of circuits such as thin-film layers and ceramic layers, circuit layers such as metals, electrode surface (catalyst) layers of fuel cells, primary batteries, and secondary batteries, and barrier layers, and the like. The functional layer 3 is preferably a thin-film optical element. In particular, an aligned liquid crystal compound layer 30 is preferable, and among these, a polarizing layer or a retardation layer is suitable as the functional layer 3. Since the base film 2 has releasability, it is possible to transfer the functional layer 3 such as the aligned liquid crystal compound layer 30 to an object.

[0064] The functional layer 3 may be provided directly on the base film 2, or may be provided on an orientation control layer 3a which is further provided on the base film 2, as shown in FIG.

[0065] The polarizing layer is preferably an absorptive polarizing layer using a liquid crystal compound and a dichroic dye, a circular polarizing layer (circularly polarized reflective layer) using a cholesteric liquid crystal compound, or a retardation layer using a liquid crystal compound. The retardation layer using a liquid crystal compound is preferably a λ / 4 retardation layer or a λ / 2 retardation layer. The retardation layer is made of a material suited to the respective functions and formed by a molding method suited to the material, and examples of the method include wet coating, vapor deposition, sputtering, CVD, and other dry film formation methods. Wet coating may be heated for crosslinking or cured by radiation after drying.

[0066] An absorptive polarizing layer and a retardation layer using a liquid crystal compound, which are preferred embodiments of the oriented liquid crystal compound layer 30 of the present invention, will be described below.

[0067] (Absorptive polarizing layer) The absorptive polarizing layer is preferably made of a liquid crystal compound and a dichroic dye, which is a dye having different absorbance in the long axis direction and the short axis direction of the molecule.

[0068] Dichroic dyes have maximum absorption wavelengths (λ MAX ) is preferred. Examples of such dichroic dyes include acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes, and anthraquinone dyes, among which azo dyes are preferred. Examples of azo dyes include monoazo dyes, bisazo dyes, trisazo dyes, tetrakisazo dyes, and stilbene azo dyes, and bisazo dyes and trisazo dyes are preferred. The dichroic dyes may be used alone or in combination, but it is preferred to combine two or more types in order to adjust the color tone to make it achromatic. It is more preferred to combine three or more types, and it is particularly preferred to combine three or more types of azo compounds.

[0069] From the viewpoint of obtaining good orientation of the dichroic dye, the content of the dichroic dye in the absorptive polarizing layer is preferably 0.1 to 30 mass %, more preferably 0.5 to 20 mass %, further preferably 1.0 to 15 mass %, and particularly preferably 2.0 to 10 mass %.

[0070] The absorptive polarizing layer preferably contains a liquid crystal compound for efficiently orienting the dichroic dye. The liquid crystal compound is preferably a polymerizable liquid crystal compound for fixing the orientation state. The polymerizable liquid crystal compound is a compound having a polymerizable group and exhibiting liquid crystallinity. The polymerizable group means a group involved in a polymerization reaction, and is preferably a photopolymerizable group. Here, the photopolymerizable group means a group that can undergo a polymerization reaction by an active radical or an acid generated from a photopolymerization initiator described later. As the polymerizable group, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group, and an oxetanyl group are preferable, and an acryloyloxy group is more preferable. The compound exhibiting liquid crystallinity may be a thermotropic liquid crystal or a lyotropic liquid crystal, and among the thermotropic liquid crystals, it may be a nematic liquid crystal or a smectic liquid crystal. Among them, a smectic liquid crystal compound is preferable, and a high-order smectic liquid crystal compound is more preferable. When the liquid crystal layer formed by the polymerizable liquid crystal compound has a high-order smectic phase, an absorptive polarizing layer having a higher degree of orientational order can be produced.

[0071] Specific preferred polymerizable liquid crystal compounds include those described in, for example, JP 2002-308832 A, JP 2007-16207 A, JP 2015-163596 A, JP 2007-510946 A, JP 2013-114131 A, WO 2005 / 045485 A, and Lub et al. Recl. Trav. Chim. Pays-Bas, 115, 321-328 (1996).

[0072] From the viewpoint of increasing the alignment property of the polymerizable liquid crystal compound, the content of the polymerizable liquid crystal compound in the absorptive polarizing layer is preferably 70 to 99.5% by mass, more preferably 75 to 99% by mass, even more preferably 80 to 97% by mass, and particularly preferably 83 to 95% by mass.

[0073] The absorptive polarizing layer can be provided by applying a composition coating to the substrate film 2. The composition coating may contain a solvent, a polymerization initiator, a sensitizer, a polymerization inhibitor, a leveling agent, a polymerizable non-liquid crystal compound, a crosslinking agent, and the like.

[0074] The composition coating may be applied onto the substrate film 2 or onto the orientation control layer 3a described in detail below, and may then be dried, heated and cured as necessary.

[0075] The thickness of the polarizing film formed from the composition coating is 0.1 to 5 μm, preferably 0.3 to 3 μm, and more preferably 0.5 to 2 μm.

[0076] (phase contrast layer) The retardation layer, which is another preferred example of the oriented liquid crystal compound layer 30 of the present invention, is a layer in which a liquid crystal compound is oriented. As the liquid crystal compound, a discotic liquid crystal compound, a rod-shaped liquid crystal compound, etc. are used. The liquid crystal compound used in the retardation layer is also preferably a polymerizable liquid crystal compound.

[0077] The retardation layer may be of various types according to the purpose, such as a positive or negative A plate, a positive or negative C plate, or an O plate. The orientation is also selected according to the type of retardation layer, such as in-plane horizontal orientation, vertical orientation, tilt orientation, and orientation in which the tilt angle of the tilt orientation changes in the thickness direction, and the type of liquid crystal compound. For example, in the case of a circular polarizing plate, a λ / 4 retardation layer with a retardation of 120 to 150 nm and a λ / 2 retardation layer with a retardation of 240 to 300 nm are selected as the A plate.

[0078] Examples of the retardation layer can be seen in JP-A-2008-149577, JP-A-2002-303722, WO 2006 / 100830, JP-A-2015-64418, and the like.

[0079] The retardation layer may be provided by applying a retardation composition paint, and the retardation composition paint may contain a solvent, a polymerization initiator, a sensitizer, a polymerization inhibitor, a leveling agent, a polymerizable non-liquid crystal compound, a crosslinking agent, and the like.

[0080] The retardation composition coating material may be applied onto the substrate film 2 or onto the orientation control layer 3a described in detail below, and may then be dried, heated and cured as necessary.

[0081] The thickness of the retardation layer is from 0.1 to 10 μm, preferably from 0.3 to 7 μm, and more preferably from 0.5 to 5 μm.

[0082] (Orientation control layer) As described above, the oriented liquid crystal compound layer 30 such as a polarizing layer or a retardation layer may be provided directly on the base film 2, but an orientation control layer 3a may be provided on the base film 2, and the oriented liquid crystal compound layer 30 may be provided on the orientation control layer 3a. In the present invention, the polarizing layer, the retardation layer, the circularly polarized light reflective layer, etc. may include an orientation control layer.

[0083] The alignment control layer 3a controls the alignment direction of the liquid crystal compound, and can provide a polarizing layer, a retardation layer, a circularly polarized light reflective layer, or the like with higher accuracy.

[0084] The alignment control layer 3a may be any alignment control layer that can bring the aligned liquid crystal compound layer 30 into a desired alignment state. Methods for imparting alignment control ability to the alignment control layer 3a include, for example, rubbing treatment on the surface, oblique deposition of an inorganic compound, and formation of a layer having microgrooves. In addition, a method of forming a photoalignment control layer that generates an alignment function by orienting molecules by irradiation with polarized light is also preferred. Below, a rubbing treatment alignment control layer and a photoalignment control layer are described as examples of preferred alignment control layer 3a.

[0085] Examples of polymer materials used for the alignment control layer 3a formed by rubbing treatment include polyvinyl alcohol and its derivatives, polyimide and its derivatives, acrylic resins, polysiloxane derivatives, etc. After applying a rubbing treatment alignment control layer coating solution containing these polymer materials onto a release film 2, the coating is dried by heating, etc., and then the coating surface is rubbed with a rubbing roller made of raised fabric of fibers such as nylon, polyester, and acrylic, to prepare the alignment control layer 3a.

[0086] The thickness of the rubbing treatment alignment control layer is preferably 0.01 to 10 μm, more preferably 0.05 to 5 μm, and particularly preferably 0.1 to 1 μm.

[0087] It is also possible to provide the surface of the base film 2 with an orientation control layer function by directly performing a rubbing treatment on the base film 2 .

[0088] Another preferred example of the alignment control layer 3a is an alignment film in which a coating liquid containing a polymer or monomer having a photoreactive group and a solvent is applied to the base film 2, and the coating liquid is irradiated with polarized light, preferably polarized ultraviolet light, to impart alignment control ability. The photoreactive group is a group that generates liquid crystal alignment ability by light irradiation. Specifically, it generates a photoreaction that is the origin of liquid crystal alignment ability, such as molecular orientation induction or isomerization reaction, dimerization reaction, photocrosslinking reaction, or photodecomposition reaction, which occurs by light irradiation. Among such photoreactive groups, those that cause dimerization reaction or photocrosslinking reaction are preferred in terms of excellent alignment control ability and maintaining the liquid crystal state of the aligned liquid crystal compound layer 30. As the photoreactive group that can cause the above reaction, a group containing an unsaturated bond, especially a double bond, is preferred, and a group having at least one selected from the group consisting of a C=C bond, a C=N bond, an N=N bond, and a C=O bond is particularly preferred.

[0089] Among them, photoreactive groups capable of causing photodimerization are preferred, and cinnamoyl and chalcone groups are preferred because they require a relatively small amount of polarized light irradiation for photoalignment and can easily produce a photoalignment control layer with excellent thermal stability and stability over time. Furthermore, as a polymer having a photoreactive group, a polymer having a cinnamoyl group at the end of the polymer side chain that has a cinnamic acid structure is particularly preferred. Examples of the main chain structure include polyimide, polyamide, (meth)acrylic, and polyester.

[0090] Specific examples of the optical alignment control layer include those described in JP-A-2006-285197, JP-A-2007-76839, JP-A-2007-138138, JP-A-2007-94071, JP-A-2007-121721, JP-A-2007-140465, JP-A-2007-156439, JP-A-2007-133184, and JP-A-2009 Examples of the orientation control layers include those described in JP-A-109831, JP-A-2002-229039, JP-A-2002-265541, JP-A-2002-317013, JP-T-2003-520878, JP-T-2004-529220, JP-A-2013-33248, JP-A-2015-7702, and JP-A-2015-129210.

[0091] By irradiating the thus obtained pre-alignment optical alignment control layer with polarized light in a predetermined oblique direction with respect to the longitudinal direction of the base film 2, an optical alignment control layer is obtained in which the orientation control direction is oblique with respect to the longitudinal direction of the long base film 2. By adjusting the angle of the irradiated polarized light, the orientation control direction of the optical alignment control layer can be adjusted as desired.

[0092] [Manufacturing method] The present invention also provides a method for producing the transfer film laminate 1. The production method according to the embodiment of the present invention includes the steps of preparing the film laminate 1, peeling the surface protective film 4 from the base film 2 of the film laminate 1, providing a functional layer 3 on the surface of the base film 2 on which the surface protective film 4 was laminated, and bonding the surface protective film 4 or another surface protective film to the surface on which the functional layer 3 is provided.

[0093] The film laminate 1 is obtained as a long object and wound up as a roll. At this time, the surface protective film 4 is laminated and wound up, which can prevent damage to the surface of the base film 2 to which the functional layer 3 is laminated. The surface protective film is knurled, which can prevent problems such as wrinkles during winding and can prevent misalignment during storage, transportation, etc. in the wound state.

[0094] The surface protective film 4 is peeled off from the base film 2 of the film laminate 1, and the functional layer 3 is provided on the surface of the base film 2 on which the surface protective film 4 was laminated. Since the surface of the base film 2 on which the functional layer 3 is provided is protected by the surface protective film 4, it is possible to provide a high-performance functional layer 3.

[0095] It is preferable that knurling is not performed on the side of the base film 2 on which the functional layer 3 is laminated. Since knurling is not performed on the side of the base film 2 on which the functional layer 3 is laminated, the knurled portion can be used without slitting and removing it in the step of transferring the functional layer 3 to an object or in the next step of providing another functional layer on the functional layer 3.

[0096] A surface protective film is laminated to the surface on which the functional layer 3 is provided, to obtain a film laminate 1 having the functional layer 3, as shown in Fig. 9. The surface protective film in this case may be the surface protective film 4 that was included in the original film laminate 1, or may be a different surface protective film. Even in the case of a different surface protective film, it is preferable that the surface protective film laminated to the functional layer 3 has been subjected to knurling in the same manner as the surface protective film 4.

[0097] By laminating a knurled surface protection film, it is possible to prevent damage to the functional layer 3 and to prevent problems such as wrinkles during winding, and misalignment during storage, transportation, etc. in the wound state. Furthermore, when the functional layer 3 is a porous body or a liquid crystal compound layer, it is possible to prevent deterioration of the functional layer 3 caused by localized high pressure on the winding core side.

[0098] The length and width of the film laminate 1 on which the functional layer 3 is laminated are the same as the preferred length and width of the base film 2, and the length and width of the surface protective film 4 are also the same as above.

[0099] [Transfer method] The present invention further provides a method for transferring the functional layer 3. The transfer method according to the embodiment of the present invention includes the steps of producing a film laminate 1 having a functional layer 3 laminated thereon by the above-mentioned production method, peeling off the surface protective film from the film laminate 1, bonding the functional layer 3 surface of the film laminate 1 to an object to be transferred, and peeling off the base film 2 from the object to be transferred.

[0100] In the process of transferring the functional layer 3 to an object, the roll of the film laminate 1 having the functional layer 3 laminated thereon and the surface protective film is unwound from the roll, and the surface protective film is peeled off. An adhesive or pressure-sensitive adhesive is provided on the functional layer 3 from which the surface protective film has been peeled off, and after it has been attached to the object, the base film 2 is peeled off.

[0101] The object is not particularly limited, but is preferably a long object such as a film or sheet processed by roll-to-roll. For example, for optical applications, transparent films, polarizing plates, retardation films, circular polarizing plates, etc. can be mentioned. For optical applications, the object provided with the functional layer 3 can be used as, for example, an anti-reflection film, an anti-glare film, a polarizing plate, a retardation plate, a circular polarizing reflector, a polarizing plate with an optical compensation layer, a circular polarizing plate, a brightness improvement film, a polarizing plate with a brightness improvement layer, a circular polarizing plate with a brightness improvement layer, etc.

[0102] This application claims the benefit of priority based on Japanese Patent Application No. 2019-148470, filed on August 13, 2019. The entire content of the specification of Japanese Patent Application No. 2019-148470, filed on August 13, 2019, is incorporated by reference into this application. EXAMPLES

[0103] The present invention will be described below with reference to examples. The present invention is not limited to the following examples, and can of course be modified within the scope of the above and below-described aims, and all such modifications are within the technical scope of the present invention.

[0104] The properties in the examples were evaluated by the following methods.

[0105] (1) Height of knurling Using a Fuji Work Handy-0.1 thickness meter, the knurled parts on both ends of the surface protection film were measured at 5 locations 3 cm apart, for a total of 10 locations, and the average value was taken as the knurled part thickness. The film thickness was also measured at a location 1 cm from the center of the knurled parts on both ends, and the average value of the 10 locations was taken as the film thickness. The height of the knurled part was determined by subtracting the film thickness from the knurled part thickness.

[0106] (2) Three-dimensional surface roughness SRa, SRz, and SRy Using a stylus-type three-dimensional roughness meter (SE-3AK, manufactured by Kosaka Laboratory Co., Ltd.), measurements were taken over a measurement length of 1 mm with a cutoff value of 0.25 mm in the longitudinal direction of the film under conditions of a needle radius of 2 μm and a load of 30 mg, with a needle feed speed of 0.1 mm / sec., and the film was divided into 500 points at a pitch of 2 μm, and the height of each point was recorded in a three-dimensional roughness analyzer (SPA-11). The same operation was performed continuously 150 times at intervals of 2 μm in the width direction of the film, that is, over a width of 0.3 mm in the width direction of the film, and the data was recorded in the analyzer. Next, the center surface average roughness (SRa), ten-point average roughness (SRz), and maximum height (SRy) were determined using the analyzer.

[0107] (3) Peel strength of surface protection film The surface protection film / substrate film laminate and the surface protection film / functional layer / substrate film laminate obtained in the Examples and Comparative Examples were cut to a width of 25 mm and a length of 160 mm to prepare samples. The length direction of the sample was the width direction of the substrate film.

[0108] The substrate film surface of the sample was laminated and attached to an acrylic plate of the same width and length as the 1 mm thick sample using double-sided tape. The surface protection film was peeled off from a portion of about 20 mm at one end of the sample, and a biaxially oriented polyester film of width 25 mm, length 160 mm, and thickness 50 μm was attached to the peeled portion of the surface protection film using double-sided tape. The substrate film or the functional layer / substrate film laminate of the portion where the surface protection film was peeled off was held together with the acrylic plate by the lower chuck of a tensile tester, and the end of the opposite side where the biaxially oriented polyester film surface protection film was attached was held by the upper chuck, and the peel strength was measured when peeled off at 180 degrees at a speed of 300 mm / min. The tester used was Shimadzu Corporation's "Autograph (registered trademark)" (AG-X), and the average value was calculated from 2 seconds to 25 seconds after the start of peeling in the measurement. The measurement was performed on five samples, and the average value was taken as the peel strength. The temperature in the measurement room was 24°C. The samples used were those which had been left for 24 hours in a room at 24°C and a relative humidity of 50% after the surface protection film had been attached.

[0109] [Example] (Manufacture of surface protection films) An antistatic surface protection film having a width of 100 cm was prepared, which had an acrylic adhesive layer of 7 μm on a 32 μm thick unstretched polypropylene (CPP) film substrate.

[0110] (Production of base film) Polyethylene terephthalate (PET) resin pellets with an intrinsic viscosity of 0.62 dl / g were dried under reduced pressure (1 Torr) at 135°C for 6 hours, then fed to an extruder and melted at 285°C. This molten polymer was filtered through a stainless steel sintered filter medium (nominal filtration accuracy of 10 μm particles, 95% cut), extruded from a die in the form of a sheet, and then wrapped around a casting drum with a surface temperature of 30°C using an electrostatic casting method, cooled and solidified to produce an unstretched film.

[0111] The unstretched film was introduced into a tenter stretching machine, and while the ends of the film were held by clips, it was introduced into a hot air zone at a temperature of 125°C and stretched 4.0 times in the width direction. Next, while maintaining the width stretched in the width direction, it was heat set at a temperature of 210°C for 10 seconds and further relaxed by 3.0%. After that, both ends of the film cooled to 130°C were cut with a shear blade and stretched at 0.5 kg / mm 2 The edges were cut off under a tension of 0.05 mm and then wound up to obtain a uniaxially oriented PET film (width 100 cm) with a film thickness of 50 μm. A surface protective film was attached to one side to obtain a film roll (film laminate 100a) with a length of approximately 500 m.

[0112] (Knurl processing) Just before laminating the surface protection film to the base film, knurling was performed on the surface of the surface protection film opposite to the surface to which the base film was to be laminated, using a heated knurling machine (180°C) for knurling, which has a quadrangular pyramid shape. The knurling process is as follows. The back roll of the heated knurling machine is a roll that has been surface-treated with a fluororesin. <Knurl processing> Height: 4.7μm Distance between recesses: 1.0mm Distance from film edge: 5mm Width: 15mm

[0113] The adhesive strength of the surface protection film to the base film was 0.11 N / 25 mm.

[0114] The surface roughness of the release surface of the base film (the surface to which the surface protective film was attached) was as follows. Center surface average roughness (SRa): 2 nm Ten-point average roughness (SRz): 11 nm Maximum height (SRy): 17 nm

[0115] (Coating of functional layer) The film laminate 100a was unwound from the roll of the film laminate 100a, the surface protection film was peeled off, and then a coating material for an orientation control layer having the following composition was applied to the surface of the base film where the surface protection film had been attached, using a bar coater, and dried at 80°C for 5 minutes to form a film with a thickness of 200 nm. The surface of the obtained film was then treated with a rubbing roll wrapped with a nylon napped cloth, to obtain a base film laminated with an orientation control layer. Rubbing was performed at an angle of 45 degrees to the film roll unwinding direction (longitudinal direction (MD)). Fully saponified polyvinyl alcohol (weight average molecular weight 800) 2 parts by weight Ion-exchanged water 100 parts by weight Surfactant 0.5 parts by weight

[0116] Subsequently, a solution for forming a retardation layer (liquid crystal compound layer) having the following composition was applied to the rubbed surface by a bar coating method. It was dried at 110°C for 3 minutes and cured by irradiation with ultraviolet light to form a λ / 4 retardation layer on the substrate film, thereby obtaining a functional layer laminate film 100. Rod-shaped liquid crystal compound (BASF LC242) 92 parts by weight Trimethylolpropane triacrylate 5 parts by weight Irgacure 379 3 parts by weight Surfactant 0.1 parts by weight Methyl ethyl ketone 250 parts by mass

[0117] The orientation control layer and the λ / 4 retardation layer were coated at intervals of about 10 mm from both ends of the substrate film in the width direction.

[0118] A surface protection film different from the film laminate 100a was attached to the λ / 4 retardation layer surface of the obtained functional layer laminate film 100, to obtain a film roll (film laminate 100b) having a length of about 500 m.

[0119] Just before laminating the surface protection film, the surface protection film was subjected to knurling using the same equipment as described above. The knurling was performed as follows. <Knurl processing> Height 5.3μm Distance between recesses: 1.0mm Distance from film edge: 5mm Width: 10mm

[0120] The adhesive strength of the surface protective film to the functional layer laminate film 100 was 0.17 N / 25 mm.

[0121] (Transfer of functional layer) After unwinding the film laminate 100b and peeling off the surface protective film, an ultraviolet-curing adhesive was applied to the functional layer surface (coating width 980 mm), attached to a polarizing plate (width 1000 mm), cured by irradiating with ultraviolet light, and then wound up into a roll. The polarizing plate used was Cosmoshine SRF (R) manufactured by Toyobo Co., Ltd., which had an anti-reflection layer as a protective film on one side of a 5 μm-thick polarizer made of polyvinyl alcohol (PVA) with iodine adsorbed thereon, and the functional layer was attached to the polarizing plate surface.

[0122] The obtained roll-shaped laminate is a laminate of polarizer protective film / polarizer / λ / 4 retardation layer / orientation control layer / substrate film, and can be used as a circular polarizing plate by peeling off the substrate film. Specifically, for example, after peeling off the substrate film, an optical adhesive sheet is laminated on the surface of the orientation control layer, the widthwise end is slit by 20 mm and removed, cut to the required length, and attached to the surface of an organic EL panel, whereby an anti-reflection circular polarizing plate can be provided on an organic EL display device. In this case, the width of the original substrate film is 1000 mm, whereas the width of the final circular polarizing plate is 960 mm, and the substrate film can be used efficiently.

[0123] The peel strength when peeling the base film from the laminate was 1.2 N / 25 mm. The peel strength was measured by attaching the polarizer protective film surface of the laminate to an acrylic plate and measuring the peel strength according to the peel strength of a surface protective film.

[0124] (Disturbance in the retardation layer on the core side) The film laminate 100b was unwound, and two samples measuring 10 cm x 10 cm were cut out from the part directly above the end of the film at the beginning of the winding at the 5th turn from the core. After peeling off the surface protection film of the samples, the two samples were aligned and overlapped, sandwiched between two polarizing plates arranged in parallel Nicol, and light was irradiated from below to observe the extinction state. There was no unevenness in the extinction state, and no disturbance of the retardation layer due to local pressure on the core side caused by knurling was observed.

[0125] [Comparative Example] (Production of base film) The base film was prepared in the same manner as in the example, but when the base film was wound up, knurling was performed using a heated knurling machine (270°C) for knurling in which a quadrangular pyramid shape was provided on the base film. The knurling process is as follows. The back roll of the heated knurling machine is a roll that has been subjected to mirror finishing. The base film was wound up without laminating a surface protection film (film 200a). <Knurl processing> Height 4.5μm Distance between recesses: 1.0mm Distance from film edge: 5mm Width: 10mm

[0126] (Coating of functional layer) The film 200a was unwound from the above-mentioned roll body, and the knurled portions on both ends were slit to a width of 20 mm and removed.After that, an orientation control layer and a retardation layer were provided on the knurled surface of the film 200a in the same manner as in the Example, and the film was wound into a roll to obtain the functional layer laminated film 200.

[0127] Just before winding, the wire was knurled using the same equipment as above. The knurling process is as follows. <Knurl processing> Height 5.0μm Distance between recesses: 1.0mm Distance from film edge: 5mm Width: 10mm

[0128] (Transfer of functional layer) The functional layer laminate film 200 was unwound, and the knurled portions at both ends were slit to a width of 20 mm and removed, and then the film was attached to a polarizing plate and wound into a roll in the same manner as in the Example. The width of the adhesive coating was 900 mm, and the width of the polarizing plate was 920 mm.

[0129] The obtained roll-shaped laminate can be used as a circular polarizing plate by peeling off the base film as in the Examples, but when the optical pressure-sensitive adhesive sheet is laminated thereon and the widthwise end is slit by 20 mm and removed as in the Examples, the final width of the circular polarizing plate is 880 mm, which is not an efficient use of the base film. [Explanation of symbols]

[0130] 1: Film laminate 2: Base film 2a: Release surface 20A: Release side layer 20B: Back side layer 20C: Middle layer 20: Base film base layer 20a: Release layer 3: Functional layer 3a: Orientation control layer 30: Alignment liquid crystal compound layer 4: Surface protection film 4b: Knurled part 40: Surface protection film base layer 40a: Adhesive layer 5: Functional layer laminated film

Claims

1. A method for producing a film laminate, comprising the steps of: A step of preparing a long-length film laminate in which a base film and a surface protective film are laminated, the material constituting the base film being at least one selected from the group consisting of polyester, polycarbonate, polystyrene, polyamide, polypropylene, cyclic polyolefin, triacetyl cellulose, and polyfluoroethylene, the surface protective film being knurled at both ends in the width direction, and the base film not being knurled; peeling the surface protective film from the base film of the film laminate; providing a functional layer on the surface of the base film on which the surface protective film was laminated; and a step of attaching a surface protection film to the surface on which the functional layer is provided.

2. A method for transferring a functional layer, comprising the steps of: Producing a film laminate by the method of claim 1; peeling the surface protective film from the film laminate; A step of bonding a functional layer surface of the film laminate to an object to be transferred; and peeling the base film from the object to be transferred.

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