Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
  • B32B37/02—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by a sequence of laminating steps, e.g. by adding new layers at consecutive laminating stations
  • B32B37/025—Transfer laminating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
  • B32B7/04—Interconnection of layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
  • B32B7/04—Interconnection of layers
  • B32B7/06—Interconnection of layers permitting easy separation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
  • B32B7/04—Interconnection of layers
  • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/30—Polarising elements
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
  • G02F1/13363—Birefringent elements, e.g. for optical compensation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
  • B32B37/14—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers
  • B32B37/26—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers with at least one layer which influences the bonding during the lamination process, e.g. release layers or pressure equalising layers
  • B32B2037/268—Release layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2305/00—Condition, form or state of the layers or laminate
  • B32B2305/55—Liquid crystals

Definitions

• the present invention relates to a laminate for transferring a thin film layer. More specifically, when transferring a thin film layer including a layer in which a liquid crystal compound is oriented, which is used in the production of a polarizing plate such as a circular polarizing plate or a retardation plate or a polarizing plate having a polarizing layer made of a liquid crystal compound.
• a polarizing plate such as a circular polarizing plate or a retardation plate or a polarizing plate having a polarizing layer made of a liquid crystal compound.
• the present invention relates to a laminate preferably used in the above.
• This transfer method is not limited to the conventional transfer of patterns, but in recent years, in the fields of optics, electrical and electronic fields, etc., a retardation layer, a polarizing layer, an absorption layer such as ultraviolet rays and infrared rays, a reflection layer, an electromagnetic wave shield layer, and an electrode
• a method has been adopted in which a thin film layer having various functions such as a layer, an antireflection layer, and a refractive index adjusting layer is provided on an object by transfer.
• a circularly polarizing plate is conventionally arranged on the panel surface of the image display panel on the viewer side in order to reduce the reflection of external light.
• This circular polarizing plate is composed of a laminate of a linear polarizing plate and a retardation film such as ⁇ / 4, and converts external light toward the panel surface of the image display panel into linearly polarized light by the linear polarizing plate, followed by ⁇ /. It is converted to circularly polarized light by a retardation film of 4 mag.
• a single retardation film such as cyclic olefin (Patent Document 1), polycarbonate (Patent Document 2), and a stretched film of triacetyl cellulose (Patent Document 3) is used.
• a retardation film a retardation film of a laminate having a retardation layer made of a liquid crystal compound on a transparent film is used (Patent Documents 4 and 5). In the above, when providing a retardation layer (liquid crystal compound layer) made of a liquid crystal compound, it is described that the liquid crystal compound may be transferred.
• Patent Document 6 a method of producing a retardation film by transferring a retardation layer made of a liquid crystal compound to a transparent film is known in Patent Document 6 and the like.
• a method is also known in which a retardation layer made of a liquid crystal compound such as ⁇ / 4 is provided on a transparent film by such a transfer method to form a ⁇ / 4 retardation film (Patent Documents 7 and 8).
• a transfer laminate in which a retardation layer in which a liquid crystal compound is oriented is provided on a releasable base film for transfer (hereinafter, may be simply referred to as a base film) is prepared, and this transfer is performed.
• the retardation layer of the laminate is bonded to a target film or the like and transferred.
• the transfer laminate is produced as a long roll, but when it is wound as a roll, a masking film may be attached to a phase difference layer and wound up in order to protect the phase layer (patented).
• Document 9 When the retardation layer is transferred to the object using the roll of the transfer laminate, the masking film is peeled off and the object and the retardation layer are bonded to each other with an adhesive or the like.
• the base film of the transfer laminate may be wound up as a roll while being laminated without being peeled off, but it is peeled off before it becomes the final product, such as when it is attached to an image display cell. NS.
• an object of the present invention is a transfer laminate for transferring a thin film layer, which can form a transfer product in which defects such as pinholes and transfer defects are suppressed. It is what we are trying to provide.
• the present inventors have defects such as pinholes in a retardation layer laminated polarizing plate (circular polarizing plate) manufactured by using a transparent resin film as a base film for transfer.
• a retardation layer laminated polarizing plate circular polarizing plate
• the transfer laminate to which the masking film is attached is stored in a roll state, and the transfer laminate is obtained from this roll. It has been found that pinholes occur when the masking film is peeled off in the process of unwinding and transferring to the object, or when the base film is peeled off.
• the laminate for thin film layer transfer of the present invention has the following points.
• the releasable base film, the thin film layer, and the masking film are laminated in this order, and are characterized by satisfying the following formulas (1), (2), and (3). 0.01 ⁇ Y / X ⁇ 0.7 (1)
• X Peeling strength between the releasable base film and the thin film layer
• Y Peeling strength between the thin film layer and the masking film
• Sku ⁇ 40 (2)
• Sku Kurtosis of the release surface of the releasable base film
• Sq Root mean square roughness of the release surface of the release base film
• the thin film layer transfer laminate of the present invention preferably further satisfies the following formula (4). -1.0 ⁇ Sk ⁇ 2.0 (4) Sk: Releasability The skewness of the release surface of the base film
• the thin film layer transfer laminate of the present invention preferably further satisfies the following formula (5). 0.005N / 25mm ⁇ Y ⁇ 2.0N / 25mm (5)
• the thin film layer preferably contains a layer in which a liquid crystal compound is oriented.
• the thin film layer transfer laminate for transferring the thin film layer of the present invention is excellent in handleability, and in particular, the thin film layer can be easily transferred to an object by roll-to-roll. Furthermore, by using the thin film layer transfer laminate of the present invention, it is possible to obtain a transferred product in which the occurrence of defects such as pinholes and transfer defects is suppressed.
• the resin constituting the base film raw material of the releasable base film is not particularly limited as long as it can maintain the strength as a transfer base material, but among them, polyester, polycarbonate, polystyrene, polyamide, polypropylene, and cyclic polyolefin. , Triacetyl cellulose is preferable, and polyethylene terephthalate, cyclic polyolefin, and triacetyl cellulose are particularly preferable.
• the releasable base film includes a layer to be post-processed, such as a coat layer to be added as needed, to the base film raw fabric obtained in the film forming step.
• the base film raw material refers to a form used for producing a laminate for transferring a liquid crystal compound, and the base film raw material refers to a state obtained in a film forming process.
• the base film raw fabric may be composed of a single layer or a plurality of layers by coextrusion. In the case of a plurality of layers, only one surface is a release surface [release surface side layer (A)] / [back surface side layer (B)], and both sides are release surfaces and another intermediate is in between.
• the configuration of the [release surface side layer (A)] / [intermediate layer (C)] / [release surface side layer (A)] having the layer (C), and only one surface is the release surface and the mold is released. Examples thereof include a configuration of a [release surface side layer (A)] / [intermediate layer (C)] / [back surface side layer (B)] having an intermediate layer (C) between the front surface and the back surface side layer.
• the "release surface side layer" of the base film raw fabric means the layer on the side where the release surface exists among each layer of the resin constituting the base film raw fabric.
• the film even when the film is a single layer, it may be referred to as a release surface side layer.
• the back surface side layer and the release surface side layer, which will be described later, are the same layer.
• the release surface side layer may be simply referred to as a surface layer.
• the base film raw fabric may be a stretched film or an unstretched film.
• stretching either uniaxial stretching, weak biaxial stretching (stretching in the biaxial direction but weak in one direction), or biaxial stretching may be used, but the orientation direction is constant over a wide range in the width direction.
• Uniaxial stretching or weak biaxial stretching is preferable in terms of being able to do so.
• weak biaxial stretching it is preferable that the main orientation direction is the stretching direction of the subsequent stage.
• the stretching direction may be the flow direction (longitudinal direction) of film production or the direction orthogonal to the flow direction (lateral direction).
• stretching in the longitudinal direction is preferably stretched by roll groups having different speed differences, and stretching in the lateral direction is preferably tenter stretching.
• the raw material of the base film is polyethylene terephthalate, it is preferably a stretched film.
• the base film raw fabric may be an easy-adhesion coating, a release coating, an antistatic coating, or the like at the time of film formation.
• the releasable base film is industrially supplied in rolls around which the film is wound.
• the lower limit of the roll width is preferably 30 cm, more preferably 50 cm, still more preferably 70 cm, particularly preferably 90 cm, and most preferably 100 cm.
• the upper limit of the roll width is preferably 5000 cm, more preferably 4000 cm, further preferably 3000 cm, even more preferably 500 cm, particularly preferably 400 cm, and most preferably 300 cm.
• 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.
• the lower limit of the thickness of the releasable base film is preferably 3 ⁇ m, more preferably 5 ⁇ m, further preferably 8 ⁇ m, particularly preferably 10 ⁇ m, and most preferably 12 ⁇ m.
• the upper limit of the thickness is preferably 150 ⁇ m, more preferably 100 ⁇ m, further preferably 80 ⁇ m, particularly preferably 70 ⁇ m, and most preferably 60 ⁇ m. Within the above range, it is easy to handle and economically advantageous in terms of cost.
• the release surface of the releasable base film is preferably smooth.
• the "release surface" of the releasable base film is intended to provide a thin film layer (for example, a liquid crystal compound layer) to be transferred on the surface of the releasable base film. Means the surface.
• the parameters of each roughness of the present invention are in accordance with ISO 25178, using a non-contact surface shape measurement system (VertScan R550H-M100 manufactured by Ryoka System Co., Ltd.) under the following conditions. It was measured.
• Measurement condition WAVE mode
• Objective lens 50x 0.5 x
• Tube lens Measurement area: 187 ⁇ m x 139 ⁇ m
• Surface correction 4th correction
• Interpolation processing Complete interpolation ISO parameter processing: S-Filter 1 ⁇ m designation
• the thin film layer transfer laminate of the present invention satisfies the following formula (2).
• Sk is a Kurtosis of the release surface of the release base film.
• Kurtosis which is one of the roughness parameters, is an index showing the sharpness of the height distribution, and the larger the value, the sharper it is, and the larger the value is when there are sharp peaks or valleys.
• the upper limit of the Kurtosis (Sku) of the release surface of the releasable base film of the present invention is 40.
• the upper limit of the Sku is more preferably 30, still more preferably 20, particularly preferably 15, and most preferably 12.
• the lower limit of Sku is not particularly defined, but 1.0 is preferable, more preferably 2.0, still more preferably 3.0, and Sku is particularly preferably more than 3.0. It is also acceptable to be 0 or more, 4.5 or more, or 5.0 or more.
• the masking film When transferring the thin film layer to the target film using the thin film layer transfer laminate, the masking film is peeled off, and the releasable base film is peeled off before the final product is produced.
• the Sk on the release surface of the releasable base film By setting the Sk on the release surface of the releasable base film to the above range, smooth peeling becomes possible, and the liquid crystal compound layer remains on the convex part of the masking film or the base film, or this part is a trigger. It is possible to effectively suppress transfer defects such as a region where the streaky liquid crystal compound layer is not transferred. Further, if the Sku is more than 3.0, 4.0 or more, 4.5 or more, or 5.0 or more, the unevenness of the release surface of the release base film has a certain degree of sharpness. , It is possible to prevent the release base film from sticking to the thin film layer and perform smooth peeling.
• the thin film layer transfer laminate of the present invention satisfies the following formula (3).
• Sq is the root mean square roughness of the release surface of the release base film.
• the upper limit of the root mean square roughness (Sq) of the release surface of the releasable base film is 20 nm, preferably 15 nm, more preferably 10 nm, still more preferably 7 nm, and most preferably 5 nm.
• the lower limit of Sq is not particularly defined, but is preferably 0.5 nm or more, more preferably 0.8 nm or more, and particularly preferably 1.0 nm or more.
• the thin film layer transfer laminate of the present invention preferably satisfies the following formula (4). -1.0 ⁇ Sk ⁇ 2.0 (4)
• Sk is the skewness of the release surface of the release base film.
• Skewness which is one of the roughness parameters, is an index showing the symmetry of the height distribution. When the value is 0, it indicates that the height distribution is vertically symmetrical, and when the value is positive, the surface has many peaks. , When the value is negative, it indicates that the surface has many valleys.
• the lower limit of the skewness (Ssk) of the release surface of the releasable base film is preferably -1.0, more preferably -0.7, and even more preferably -0.5, particularly. It is preferably ⁇ 0.3.
• the releasable base film can be stably wound.
• the upper limit of Ssk on the release surface of the releasable base film is preferably 2.0, more preferably 1.7, still more preferably 1.5, and particularly preferably 1.3. Most preferably, it is 0.6. By setting the above range, transfer defects can be further suppressed. Further, since the surface of the release base film can be a surface having a certain number of peaks rather than valleys, it is possible to suppress the release base film from sticking to the thin film layer and perform smooth peeling.
• the upper limit of the arithmetic mean roughness (Sa) of the release surface of the releasable base film is preferably 15 nm, more preferably 10 nm, still more preferably 5 nm, particularly preferably 4 nm, and most preferably. Is 3 nm.
• the lower limit of Sa on the release surface of the releasable base film is preferably 0.2 nm, more preferably 0.4 nm, and even more preferably 0.5 nm.
• the upper limit of the developing area (Sdr) of the interface of the release surface of the releasable base film is preferably 0.0015%, more preferably 0.001%, and further preferably 0.0007%. By setting the above or less, it is possible to suppress problems such as defects in the thin film layer itself when the thin film layer is provided on the releasable base film, and transfer defects during transfer.
• the lower limit of the developed area (Sdr) of the interface is preferably 0.0001%. Sdr is an index showing how large the area of the actual interface is with respect to the area seen from the upper part, and tends to be large when there are many small irregularities and when the inclination of the irregularities is steep. It is considered that the smaller the Sdr, the less the catch during transfer, and the more the transfer defect can be suppressed.
• the lower limit of the average (Spc) of the principal curvatures of the peaks of the release surface of the releasable base film is preferably 1 (1 / mm), more preferably 3 (1 / mm), and even more preferably. It is 5 (1 / mm), particularly preferably 7 (1 / mm), and most preferably 8 (1 / mm). It can be done by making it more than the above.
• the upper limit of the average (Spc) of the principal curvatures of the peaks of the release surface of the releasable base film is preferably 100 (1 / mm), more preferably 80 (1 / mm), and even more preferably.
• Spc is an index showing the curvature of the apex of the protrusion, and the larger the value, the sharper the apex, and the smaller the value, the smoother the apex. It is considered that if the apex of the roughness of the release surface of the releasable base film is smooth, the catching at the time of transfer can be reduced and the transfer failure can be suppressed.
• it may be a negative value depending on the software used, but the above range may be applied as an absolute value.
• the surface layer contains substantially no particles for smoothing.
• substantially free of particles means that the particle content is less than 50 ppm, preferably less than 30 ppm.
• the surface layer may contain particles in order to increase the slipperiness of the surface.
• the lower limit of the surface particle content is preferably 10 ppm, more preferably 50 ppm, and even more preferably 100 ppm.
• the upper limit of the surface particle content is preferably 20000 ppm, more preferably 10000 ppm, still more preferably 8000 ppm, and particularly preferably 6000 ppm. If it exceeds the above, the roughness of the surface layer may not be within a preferable range.
• the lower limit of the surface particle size is preferably 0.005 ⁇ m, more preferably 0.01 ⁇ m, and even more preferably 0.02 ⁇ m.
• the upper limit of the surface particle size is preferably 1 ⁇ m, more preferably 0.5 ⁇ m, still more preferably 0.3 ⁇ m, and particularly preferably 0.1 ⁇ m. If it exceeds the above, the roughness of the surface layer may not be within the preferable range, and even if the smoothing coating is applied, the roughness of the release surface may not be within the preferable range.
• the surface layer does not contain particles or the particles have a small particle size
• the lower layer contains particles
• the roughness of the release surface layer may increase due to the influence of the particles in the lower layer.
• the lower limit of the surface layer thickness is preferably 0.1 ⁇ m, more preferably 0.5 ⁇ m, further preferably 1 ⁇ m, particularly preferably 3 ⁇ m, and most preferably 5 ⁇ m.
• the upper limit of the surface layer thickness is preferably 97%, more preferably 95%, and even more preferably 90% with respect to the total thickness of the releasable base film.
• the particle-free intermediate layer is substantially free of particles, and the particle content is less than 50 ppm, preferably less than 30 ppm.
• the lower limit of the thickness of the intermediate layer is preferably 10%, more preferably 20%, still more preferably 30% with respect to the total thickness of the releasable base film.
• the upper limit is preferably 95%, more preferably 90%.
• a flattening coat may be provided.
• the resin used for the flattening coat include those generally used as a resin for a coating agent such as polyester, acrylic, polyurethane, polystyrene, and polyamide. It is also preferable to use a cross-linking agent such as melamine, isocyanate, epoxy resin, or oxazoline compound. These are applied and dried as a coating agent dissolved or dispersed in an organic solvent or water. Alternatively, in the case of acrylic, it may be coated without a solvent and cured by radiation.
• the flattening coat may be an oligomer block coat. When the release layer is provided with a coat, the release layer itself may be thickened.
• the lower limit of the thickness of the surface flattening coat layer is preferably 0.01 ⁇ m, more preferably 0.1 ⁇ m, further preferably 0.2 ⁇ m, and particularly preferably 0.3 ⁇ m. If it is less than the above, the flattening effect may be insufficient.
• the upper limit of the thickness of the surface flattening coat layer is preferably 10 ⁇ m, more preferably 7 ⁇ m, further preferably 5 ⁇ m, and particularly preferably 3 ⁇ m. Even if it exceeds the above, a further flattening effect may not be obtained.
• the flattening coat may be provided as an in-line coat during the film forming process, or may be separately provided offline.
• Sk or Sk may not satisfy the above-mentioned preferable range. In that case, it can be within the range by referring to the above guideline.
• the base film raw material is mainly a stretched film
• the film is not formed by a casting method in which a dope prepared by dissolving triacetyl cellulose or the like in a solvent is developed on a metal belt or the like and the solvent is dried.
• a stretched film by adding the particles, unevenness due to the particles is generated on the upper surface (opposite surface of the metal belt) as the solvent is removed, so that the roughness can be adjusted.
• the above (a) to (i) are preferable methods.
• a filter is applied during the production of the raw material resin, and a filter is applied to the dope to remove agglomerated particles and foreign substances.
• the dope contains particles
• unevenness due to the particles may appear on the metal belt surface. It is also preferable to peel off. Roughness can also be adjusted at the timing of these peelings. Further, when stretching and drying in a tenter with a small amount of solvent contained, the roughness can be adjusted by a stretching ratio or the like. When particles are not contained, the roughness of the metal belt may be adjusted so that the metal belt surface is the back surface. Further, the roughness may be transferred to the surface while being dried while being passed between rolls having different roughness.
• the roughness can be adjusted by adding particles.
• particles having a coefficient of thermal expansion different from that of the film resin, such as inorganic particles it is possible to form irregularities on the surface due to the added particles due to heat shrinkage that occurs during cooling.
• the cooling roll may be roughened to transfer the roughness and used as the back surface. Roughness may be transferred between rolls having different roughness at a temperature of Tg or more of the film resin. Further, even in the case of an unstretched film, the above (a) to (i) are preferable methods.
• the lower limit of the arithmetic mean roughness (Sa) of the surface (back surface) opposite to the release surface of the releasable base film is preferably 1.0 nm, more preferably 1.3 nm, and even more preferably. It is 1.5 nm.
• the upper limit of Sa on the back surface is preferably 50 nm, more preferably 40 nm, and even more preferably 30 nm.
• the lower limit of the root mean square roughness (Sq) of the back surface of the releasable base film is preferably 1.3 nm, more preferably 1.5 nm, still more preferably 1.8 nm, and particularly preferably. It is 2.0 nm.
• the upper limit of Sq on the back surface is preferably 70 nm, more preferably 60 nm, still more preferably 50 nm, and particularly preferably 45 nm.
• the releasable base film can be easily wound, and even when the releasable base film is stored in the wound state, unwinding and blocking occur. Furthermore, it is difficult, and even when the unevenness of the back surface is transferred to the front surface, the state of surface roughness can be maintained within an appropriate range.
• the Sku on the back surface of the releasable base film is preferably larger than the Sku on the releasable surface.
• the lower limit of (Sku on the back surface) / (Sku on the release surface) is preferably 1.2, more preferably 1.4, and even more preferably 1.5.
• the upper limit of (Sku on the back surface) / (Sku on the release surface) is preferably 40, more preferably 30, still more preferably 25, and particularly preferably 20.
• the upper limit of the Sku on the back surface of the releasable base film is preferably 200, more preferably 170.
• the lower limit of the Sku on the back surface is preferably 3, more preferably 5, and even more preferably 7.
• the Ssk on the back surface of the releasable base film is preferably larger than the Ssk on the releasable surface.
• the lower limit of the absolute value of (Ssk on the back surface) / (Ssk on the release surface) is preferably 1.2, more preferably 1.5, still more preferably 1.8, and particularly preferably 2. ..
• the upper limit of (Ssk on the back surface) / (Ssk on the release surface) is preferably 20, more preferably 17, and even more preferably 15.
• the lower limit of Ssk on the back surface of the releasable base film is preferably -3, more preferably -1, but more than 0 is preferable for stable winding, and further 1 or more. Is preferable.
• the upper limit of Ssk on the back surface of the releasable base film is preferably 20, more preferably 15, still more preferably 12, and particularly preferably 10.
• the back surface side layer (back surface layer) of the base film raw fabric contains specific particles.
• a base film that contains particles in the intermediate layer of the original fabric, and reduce the thickness by assuming that the back surface layer side (back surface layer) does not contain particles.
• a flattening coat is provided.
• an easy-to-slip coat is provided.
• the lower limit of the particle size of the back surface layer is preferably 0.01 ⁇ m, more preferably 0.05 ⁇ m, and further preferably 0.1 ⁇ m. If it is less than the above, the slipperiness is deteriorated and winding failure may occur.
• the upper limit of the particle size of the back surface layer is preferably 5 ⁇ m, more preferably 3 ⁇ m, and even more preferably 2 ⁇ m. If it exceeds the above, the back surface may become too rough.
• the lower limit of the back surface layer particle content is preferably 50 ppm, more preferably 100 ppm. If it is less than the above, the slippery effect due to the addition of particles may not be obtained.
• the upper limit of the back layer particle content is preferably 10000 ppm, more preferably 7000 ppm, and even more preferably 5000 ppm. If it exceeds the above, the back surface may become too rough.
• the lower limit of the back surface layer thickness is preferably 0.1 ⁇ m, more preferably 0.5 ⁇ m, further preferably 1 ⁇ m, particularly preferably 3 ⁇ m, and most preferably 5 ⁇ m.
• the upper limit of the back surface layer thickness is preferably 95%, more preferably 90%, and even more preferably 85% with respect to the total thickness of the releasable base film.
• the particle size and the amount of particles added in the intermediate layer are the same as those in the back surface layer.
• the lower limit of the thickness of the back surface layer is preferably 0.5 ⁇ m, more preferably 1 ⁇ m, and even more preferably 2 ⁇ m.
• the upper limit of the thickness is preferably 30 ⁇ m, more preferably 25 ⁇ m, and even more preferably 20 ⁇ m.
• the back surface of the base film raw fabric is rough, it is also preferable to provide a flattening coat.
• a flattening coat those listed in the surface flattening coat can be used in the same manner.
• the lower limit of the thickness of the back surface flattening coat layer is preferably 0.01 ⁇ m, more preferably 0.03 ⁇ m, and further preferably 0.05 ⁇ m. If it is less than the above, the flattening effect may be reduced.
• the upper limit of the thickness of the back surface flattening coat layer is preferably 10 ⁇ m, more preferably 5 ⁇ m, and even more preferably 3 ⁇ m. Even if it exceeds the above, the effect of flattening will be saturated.
• the back surface side of the base film raw fabric may not contain particles, and an easy-slip coat layer containing particles may be provided on the back surface side. Further, when the roughness of the back surface of the base film raw fabric is small, an easy-to-slip coat layer may be provided.
• the lower limit of the particle size of the back surface slippery coat layer is preferably 0.01 ⁇ m, more preferably 0.05 ⁇ m. If it is less than the above, slipperiness may not be obtained.
• the upper limit of the particle size of the back surface slippery coat layer is preferably 5 ⁇ m, more preferably 3 ⁇ m, still more preferably 2 ⁇ m, and particularly preferably 1 ⁇ m. If it exceeds the above, the roughness of the back surface may be too high.
• the lower limit of the particle content of the back surface slippery coat layer is preferably 0.1% by mass, more preferably 0.5% by mass, still more preferably 1% by mass, and particularly preferably 1.5% by mass. Most preferably, it is 2% by mass. If it is less than the above, slipperiness may not be obtained.
• the upper limit of the particle content of the back surface slippery coat layer is preferably 20% by mass, more preferably 15% by mass, and further preferably 10% by mass. If it exceeds the above, the roughness of the back surface may be too high.
• the lower limit of the thickness of the back surface easy-slip coat layer is preferably 0.01 ⁇ m, more preferably 0.03 ⁇ m, and further preferably 0.05 ⁇ m.
• the upper limit of the thickness of the back surface slippery coat layer is preferably 10 ⁇ m, more preferably 5 ⁇ m, further preferably 3 ⁇ m, particularly preferably 2 ⁇ m, and most preferably 1 ⁇ m.
• the releasable base film of the present invention is a stretched film
• the film is formed by a casting method in which a dope obtained by dissolving triacetyl cellulose or the like in a solvent is developed on a metal belt or the like and the solvent is dried.
• the unstretched film by adding the particles, unevenness due to the particles is generated on the upper surface (opposite surface of the metal belt) as the solvent is removed, so that the roughness can be adjusted.
• the dope contains particles
• unevenness due to the particles may appear on the metal belt surface. It is also preferable to peel off. Roughness can also be adjusted at the timing of these peelings. Further, when stretching and drying in a tenter with a small amount of solvent contained, the roughness can be adjusted by a stretching ratio or the like. When particles are not contained, the roughness of the metal belt may be adjusted so that the metal belt surface is the back surface. Further, the roughness may be transferred to the surface while being dried while being passed between rolls having different roughness.
• the roughness can be adjusted by adding particles.
• particles having a coefficient of thermal expansion different from that of the film resin, such as inorganic particles it is possible to form irregularities on the surface due to the added particles due to heat shrinkage that occurs during cooling.
• the cooling roll may be roughened to transfer the roughness and used as the back surface. Roughness may be transferred between rolls having different roughness at a temperature of Tg or more of the film resin.
• the roughness of these unstretched films can be adjusted by a smooth coating or an easy-slip coating containing particles.
• the thin film layer preferably contains a layer in which the liquid crystal compound is oriented.
• the thin film layer may be a retardation layer, a polarizing layer, an absorption layer such as ultraviolet rays or infrared rays, a reflection layer, an electromagnetic wave shield layer, an electrode layer, an antireflection layer, a refractive index adjusting layer, or the like.
• These thin film layers may be a single layer or a plurality of layers.
• the lower limit of the thickness of the thin film layer is preferably 0.001 ⁇ m, more preferably 0.005 ⁇ m, and even more preferably 0.01 ⁇ m.
• the upper limit of the thickness is preferably 20 ⁇ m, more preferably 10 ⁇ m, still more preferably 7 ⁇ m, particularly preferably 5 ⁇ m, and most preferably 4.5 ⁇ m.
• the total thickness is preferably in the above range.
• liquid crystal compound layer which is a thin film layer suitable for the present invention.
• the liquid crystal compound layer is used as a retardation layer or a polarizing layer, and in this case, the liquid crystal compound layer needs to be coated and oriented on the releasable base film.
• a method of orienting a method of giving an orientation control function by rubbing treatment or the like on the lower layer (separation surface) of the liquid crystal compound layer, or a method of directly orienting the liquid crystal compound by irradiating polarized ultraviolet rays or the like after applying the liquid crystal compound. There is.
• orientation control layer Further, a method in which an orientation control layer is provided on the releasable base film and a liquid crystal compound layer is provided on the orientation control layer is also preferable.
• the orientation control layer may be any orientation control layer as long as the liquid crystal compound layer can be brought into a desired orientation state.
• a preferred example is a photo-orientation control layer that orients molecules by irradiation with polarized light to generate an orientation function.
• a method for forming the rubbing treatment orientation control layer will be described.
• a coating material for forming a rubbing treatment orientation control layer containing the above polymer material is applied onto the release surface of a releasable base film, and then heat-dried to obtain an orientation control layer before the rubbing treatment.
• the coating material for forming a rubbing orientation control layer may have a cross-linking agent.
• the solvent for the coating material for forming the rubbing treatment orientation control layer can be used without limitation as long as it dissolves the polymer material.
• Specific examples include water, alcohol solvents, ester solvents, ketone solvents, aromatic hydrocarbon solvents, ether solvents and the like. These solvents may be used alone or in combination.
• the thickness of the rubbing treatment orientation control layer is preferably 0.01 to 10 ⁇ m, more preferably 0.05 to 5 ⁇ m, and particularly preferably 0.1 ⁇ m to 1 ⁇ m.
• the rubbing treatment can generally be carried out by rubbing the surface of the polymer layer with paper or cloth in a certain direction.
• a rubbing roller of a brushed cloth made of fibers such as nylon, polyester, and acrylic is used to rub the surface of the orientation control layer.
• the photo-orientation control layer is a coating containing a polymer or monomer having a photoreactive group and a solvent (paint for forming a photo-orientation control layer) applied to the release surface of a releasable base film, and is polarized, preferably. It refers to an alignment film that is given an orientation-regulating force by irradiating it with polarized ultraviolet light.
• the photoreactive group is a group that produces a liquid crystal alignment ability by irradiation with light.
• a group having at least one selected from the above is particularly preferable.
• a photoreactive group capable of causing a photodimerization reaction is preferable, and a photo-alignment layer in which a cinnamoyl group and a chalcone group require a relatively small amount of polarization for photo-orientation and is excellent in thermal stability and temporal stability is obtained. It is preferable because it is easy to obtain.
• a polymer having a photoreactive group a polymer having a cinnamoyl group such that the terminal portion of the side chain of the polymer has a cinnamic acid structure is particularly preferable.
• the structure of the main chain include polyimide, polyamide, (meth) acrylic, polyester, and the like.
• the direction of the orientation regulating force of the optical orientation control layer can be arbitrarily adjusted.
• the orientation control layer is peeled off together with the liquid crystal compound layer and transferred. Further, the alignment control layer and the liquid crystal compound layer may be collectively referred to as a liquid crystal compound layer.
• the liquid crystal compound layer is not particularly limited as long as the liquid crystal compound is oriented. Specific examples include a polarizing film (polarizer) containing a liquid crystal compound and a dichroic dye, a retardation layer containing a rod-shaped or discotic liquid crystal compound, and a circularly polarized light reflecting layer having a cholesteric liquid crystal structure containing a rod-shaped liquid crystal compound. Can be mentioned.
• polarizer polarizing film
• the polarizing film has a function of passing polarized light in only one direction and contains a dichroic dye.
• the dichroic dye refers to a dye having a property in which the absorbance in the major axis direction and the absorbance in the minor axis direction of the molecule are different.
• the dichroic dye preferably has an absorption maximum wavelength ( ⁇ MAX) in the range of 300 to 700 nm.
• a bicolor dye examples include an acridine dye, an oxazine dye, a cyanine dye, a naphthalene dye, an azo dye and an anthraquinone dye, and among them, the azo dye is preferable.
• the azo dye examples include a monoazo dye, a bisazo dye, a trisazo dye, a tetrakisazo dye and a stilbene azo dye, and preferably a bisazo dye and a trisazo dye.
• the dichroic dyes may be used alone or in combination, but in order to adjust the color tone (achromatic color), it is preferable to combine two or more kinds, and it is more preferable to combine three or more kinds. In particular, it is preferable to combine three or more kinds of azo compounds.
• Preferred azo compounds include dyes described in JP-A-2007-126628, JP-A-2010-168570, JP-A-2013-101328, and JP-A-2013-210624.
• the dichroic dye is a dichroic dye polymer introduced into the side chain of a polymer such as acrylic.
• dichroic dye polymers include polymers listed in JP-A-2016-4055 and polymers obtained by polymerizing compounds [Chemical formula 6] to [Chemical formula 12] in JP-A-2014-206682.
• the content of the dichroic dye in the polarizing film is preferably 0.1 to 30% by mass, more preferably 0.5 to 20% by mass in the polarizing film from the viewpoint of improving the orientation of the dichroic dye. , 1.0 to 15% by mass is more preferable, and 2.0 to 10% by mass is particularly preferable.
• the polarizing film further contains a polymerizable liquid crystal compound in order to improve the film strength, the degree of polarization, and the film homogeneity.
• the polymerizable liquid crystal compound also includes a film after polymerization.
• the polymerizable liquid crystal compound is a compound having a polymerizable group and exhibiting liquid crystallinity.
• the polymerizable group means a group involved in the polymerization reaction, and is preferably a photopolymerizable group.
• the photopolymerizable group refers to a group that can undergo a polymerization reaction with an active radical, an acid, or the like generated from a photopolymerization initiator described later.
• Examples of the polymerizable group include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxylanyl group, an oxetanyl group and the like.
• an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxylanyl group and an oxetanyl group are preferable, and an acryloyloxy group is more preferable.
• the liquid crystal compound may be a thermotropic liquid crystal or a riotropic liquid crystal, and may be a nematic liquid crystal or a smectic liquid crystal in the thermotropic liquid crystal.
• a smectic liquid crystal compound is preferable in that higher polarization characteristics can be obtained, and a higher-order smectic liquid crystal compound is more preferable.
• the liquid crystal phase formed by the polymerizable liquid crystal compound is a higher-order smectic phase, a polarizing film having a higher degree of orientation order can be produced.
• Specific preferred polymerizable liquid crystal compounds include, for example, JP-A-2002-308832, JP-A-2007-16207, JP-A-2015-163596, JP-A-2007-510946, JP-A-2013-114131. No., WO2005 / 045485, Lub et al. Recl. Trav. Chim. Examples thereof include those described in Pays-Bas, 115, 321-328 (1996) and the like.
• the content ratio of the polymerizable liquid crystal compound in the polarizing film is preferably 70 to 99.5% by mass, more preferably 75 to 99% by mass, and further preferably 75 to 99% by mass in the polarizing film from the viewpoint of increasing the orientation of the polymerizable liquid crystal compound. It is preferably 80 to 97% by mass, and particularly preferably 83 to 95% by mass.
• the polarizing film can be provided by applying a coating for forming a polarizing film.
• the coating material for forming a polarizing film may contain a solvent, a polymerization initiator, a sensitizer, a polymerization inhibitor, a leveling agent, a polymerizable non-liquid crystal compound, a cross-linking agent and the like.
• the polymerizable non-liquid crystal compound is preferably one that copolymerizes with the polymerizable liquid crystal compound.
• (meth) clearates can be mentioned.
• the (meth) clearates may be monofunctional or polyfunctional.
• polyfunctional (meta) clearates the strength of the polarizing film can be improved.
• a polymerizable non-liquid crystal compound it is preferably 1 to 15% by mass, more preferably 2 to 10% by mass, and particularly preferably 3 to 7% by mass in the polarizing film. If it exceeds 15% by mass, the degree of polarization may decrease.
• cross-linking agent examples include a polymerizable liquid crystal compound and a compound capable of reacting with a functional group of a polymerizable non-liquid crystal compound, and examples thereof include an isocyanate compound, a melamine, an epoxy resin, and an oxazoline compound.
• the polarizing film is provided by applying the polarizing film forming paint directly on the releasable base film or the orientation control layer, and then drying, heating, and curing as necessary.
• Heat treatment can be performed to more strongly orient the dichroic dye and the polymerizable liquid crystal compound in the polarizing film.
• the heating temperature is preferably in the temperature range in which the polymerizable liquid crystal compound forms a liquid crystal phase.
• the coating film for forming a polarizing film contains a polymerizable liquid crystal compound
• the curing method include heating and light irradiation, and light irradiation is preferable.
• the dichroic dye can be fixed in an oriented state.
• the curing is preferably carried out in a state where the polymerizable liquid crystal compound has a liquid crystal phase formed therein, and may be cured by irradiating light at a temperature indicating the liquid crystal phase.
• the light in the light irradiation include visible light, ultraviolet light and laser light. Ultraviolet light is preferable because it is easy to handle.
• the polarizing film By applying the polarizing film forming paint on the alignment control layer, the polarizing film is oriented along the orientation direction of the alignment layer, and as a result, the polarizing film has a polarization transmission axis in a predetermined direction.
• the polarizing film can be oriented by irradiating polarized light to cure the liquid crystal compound and the dye. At this time, polarized light in an oblique direction with respect to the longitudinal direction of the releasable base film is irradiated. Further, it is preferable that the dichroic dye is firmly oriented along the orientation direction of the polymer liquid crystal by heat treatment at that time.
• the thickness of the polarizing film is preferably 0.1 to 5 ⁇ m, more preferably 0.3 to 3 ⁇ m, and even more preferably 0.5 to 2 ⁇ m.
• Phase difference layer Typical examples of the retardation layer are those provided for optical compensation between the polarizer of the liquid crystal display device and the liquid crystal cell, and ⁇ / 4 layer and ⁇ / 2 layer of a circular polarizing plate.
• the liquid crystal compound a rod-shaped liquid crystal compound, a discotic liquid crystal compound, or the like can be used depending on the purpose, such as a positive or negative A plate, a positive or negative C plate, or an O plate.
• the liquid crystal compound used for these retardation layers is preferably a polymerizable liquid crystal compound having a polymerizable group such as a double bond in terms of being able to fix the orientation state.
• rod-shaped liquid crystal compound examples include JP-A-2002-030042, JP-A-2004-204190, JP-A-2005-263789, JP-A-2007-119415, JP-A-2007-186430, and special publications. Examples thereof include rod-shaped liquid crystal compounds having a polymerizable group described in Kaihei 11-513360.
• m and n are integers of 2 to 6 and Ph1 and Ph2 are 1,4-phenyl groups (Ph2 may have a methyl group at the 2-position).
• NPh is a 2,6-naphthyl group.
• These rod-shaped liquid crystal compounds are commercially available from BASF as LC242 and the like, and they can be used. A plurality of these rod-shaped liquid crystal compounds may be used in combination at any ratio.
• Examples of the discotic liquid crystal compound include a benzene derivative, a tolucene derivative, a cyclohexane derivative, an aza-crown derivative, a phenylacetylene macrocycle, and the like, and various ones are described in JP-A-2001-155866. Is preferably used.
• a compound having a triphenylene ring represented by the following general formula (1) is preferably used as the discotic compound.
• R 1 to R 6 are independently represented by hydrogen, halogen, alkyl group, or —X (where X is an alkyl group, an acyl group, an alkoxybenzyl group, or an epoxy-modified group.
• R 1 to R 6 are preferably acryloyloxy-modified alkoxybenzyl groups represented by the following general formula (2) (where m is 4 to 10).
• the retardation layer can be provided by applying a paint for forming a retardation layer.
• the retardation layer forming coating material may contain a solvent, a polymerization initiator, a sensitizer, a polymerization inhibitor, a leveling agent, a polymerizable non-liquid crystal compound, a cross-linking agent and the like. As these, those described in the orientation control layer and the liquid crystal polarizer can be used.
• a retardation layer is provided by applying a paint for forming a retardation layer on a release surface or an orientation control layer of a releasable base film, and then drying, heating, and curing.
• a paint for forming a retardation layer on a release surface or an orientation control layer of a releasable base film, and then drying, heating, and curing.
• the conditions described in the orientation control layer and the liquid crystal polarizer are used as preferable conditions.
• the circularly polarized light reflecting layer is preferably a cholesteric liquid crystal oriented liquid crystal compound.
• the liquid crystal compound the rod-shaped liquid crystal compound mentioned in the above retardation layer can be mentioned as a preferable example.
• a chiral agent In order to orient the liquid crystal compound of the circularly polarized light reflecting layer in a cholesteric liquid crystal, it is preferable to add a chiral agent to the liquid crystal compound.
• the chiral agent has the function of inducing the helical structure of the cholesteric liquid crystal phase.
• Examples of chiral agents include Liquid Crystal Device Handbook (Chapter 3, 4-3, TN, Chiral Auxiliary for STN, 199 pages, edited by the 142nd Committee of the Japan Society for the Promotion of Science, 1989), JP-A-2003-287623, JP. Examples thereof include the compounds described in JP-A-2002-302487, JP-A-2002-80478, JP-A-2002-80851, JP-A-2010-181852, and JP-A-2014-034581.
• the chiral agent generally contains an asymmetric carbon atom, but an axial asymmetric compound or a surface asymmetric compound that does not contain an asymmetric carbon atom can also be used as the chiral agent.
• Examples of axial or asymmetric compounds include binaphthyl, helicene, paracyclophane and derivatives thereof.
• the chiral agent may be a liquid crystal compound.
• the chiral agent preferably has a polymerizable group. By having the same polymerizable group as the liquid crystal compound, the cholesteric liquid crystal structure can be immobilized together with the liquid crystal compound.
• an isosorbide derivative, an isomannide derivative, or a binaphthyl derivative can be preferably used.
• an isosorbide derivative a commercially available product such as LC-756 manufactured by BASF may be used.
• the chiral agent is preferably 0.01 mol% to 200 mol%, more preferably 1 mol% to 30 mol%, based on the total molar amount of the polymerizable liquid crystal compound.
• the circularly polarized light reflecting layer can be provided on the releasable base film in the same manner as the above retardation layer.
• a plurality of liquid crystal compound layers may be provided on the releasable base film.
• a plurality of retardation layers, a plurality of circularly polarized light reflecting layers, a polarizing layer and a retarding layer, a polarizing layer and a circularly polarized light reflecting layer, and a circularly polarized light reflecting layer and a retardation layer may be provided.
• an interlayer protective coating layer is provided between the polarizer and the retardation layer, between the retardation layer and the circularly polarized light reflecting layer, above the retardation layer, between the retardation layers, etc. to prevent the transfer of components of each layer.
• These interlayer protection coating layers may also be provided on the releasable base film together with the retardation layer, the polarizing layer, and the circularly polarized light reflecting layer and transferred to the object.
• the interlayer protection coat layer examples include a transparent resin coating layer.
• the transparent resin is not particularly limited to polyvinyl alcohol, ethylene vinyl alcohol copolymer, polyester, polyurethane, polyamide, polystyrene, acrylic resin, epoxy resin and the like.
• a cross-linking agent may be added to these resins to form a cross-linked structure.
• a photocurable composition such as a hard coat may be cured.
• the interlayer protection coat layer may be subjected to a rubbing treatment, and a liquid crystal compound layer may be provided on the interlayer protection coat layer without providing an orientation control layer.
• a masking film is bonded on the thin film layer (the surface of the thin film layer opposite to the surface facing the releasable base film).
• the masking film is composed of at least a base material layer and an adhesive layer, and the adhesive layer surface of the masking film is directly bonded onto the thin film layer or the interlayer protective coating layer.
• the base material of the masking film is preferably a resin film, and examples of the film material include polypropylene, polyethylene, polyester, polyamide, and polyurethane. Of these, polypropylene, polyethylene and polyethylene terephthalate are preferable. These may be copolymerized in order 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.
• Conventional adhesives such as rubber, acrylic, and polyolefin can be used for the adhesive layer of the masking film.
• the rubber type include rubbers such as natural rubber, butadiene rubber and isoprene rubber, and styrene block copolymer elastomers such as SBS, SIS, SEBS and SEPS.
• SBS styrene block copolymer elastomers
• the acrylic system the copolymer weight of methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, etc.
• Examples include cross-linked coalescing.
• the cross-linking agent include isocyanate compounds, epoxy compounds, metal chelating agents, and compounds containing a plurality of double bonds.
• polyolefin-based material examples include ethylene-propylene rubber such as EPM and EPDM, those in which these are soft segments and polyethylene or polypropylene is used as a hard segment, and blends of ethylene-propylene rubber and polyethylene or polypropylene.
• Various adhesive strength modifiers and stabilizers such as tack fire, fatty acid esters, fatty acid bisamides, polyglycerin, silicone oil, and silicone resin may be added to these pressure-sensitive adhesives.
• Examples of the adhesive include a method of applying the adhesive to a resin film as a base material and a method of co-extruding the resin of the base material and the resin to be an adhesive layer at the time of forming the resin film.
• the masking film has a thin film layer provided on the releasable base film, is bonded before being wound up, and then wound up in a roll shape.
• the present invention is a laminate in which a releasable base film, a thin film layer, and a masking film are laminated in this order, and the peel strength between the releasable base film and the thin film layer is X (N / 25 mm).
• the peel strength between the thin film layer and the masking film is Y (N / 25 mm)
• the following formula (1) is satisfied. 0.01 ⁇ Y / X ⁇ 0.7 (1)
• the lower limit of Y / X is more preferably 0.02, further preferably 0.03, particularly preferably 0.04, and most preferably 0.05.
• the upper limit of Y / X is more preferably 0.6, further preferably 0.5, particularly preferably 0.4, and most preferably 0.35.
• Y / X to the above value or more, stable handling is possible without the masking film being unnecessarily peeled off when handling the thin film layer transfer laminate, such as winding, unwinding, and slitting. Further, when the thin film layer is transferred to the object using the thin film layer transfer laminate, the releasable base film is easily peeled off, and pinholes and transfer defects are less likely to occur in the thin film layer at the time of peeling.
• the masking film can be easily peeled off when the masking film is peeled off from the thin film layer transfer laminate, and pinholes or the thin film layer can be peeled off in the liquid crystal compound layer at the time of peeling. It becomes difficult to get up.
• the peel strength Y between the thin film layer and the masking film preferably satisfies the following formula (5). 0.005N / 25mm ⁇ Y ⁇ 2.0N / 25mm (5)
• the lower limit of the peel strength Y between the thin film layer and the masking film is preferably 0.005 N / 25 mm, more preferably 0.01 N / 25 mm, further preferably 0.03 N / 25 mm, and particularly preferably 0. It is .05N / 25mm.
• the upper limit of the peel strength Y is preferably 2.0 N / 25 mm, more preferably 1.5 N / 25 mm, still more preferably 1.2 N / 25 mm, and even more preferably 1.0 N / 25 mm. Yes, particularly preferably 0.7 N / 25 mm, most preferably 0.5 N / 25 mm.
• the peel strength Y between the thin film layer and the masking film By setting the peel strength Y between the thin film layer and the masking film to the above or higher, stable handling is possible without the masking film being unnecessarily peeled off during winding, unwinding, slitting, etc. of the thin film layer transfer laminate. It will be possible. Further, by setting the peel strength Y between the thin film layer and the masking film to the above or less, the releasable base film can be easily peeled off when the thin film layer is transferred to the object using the thin film layer transfer laminate. , Pinholes and transfer defects are less likely to occur in the thin film layer during peeling.
• the peel strength Y between the thin film layer and the masking film can be adjusted according to the composition of the thin film layer and the like, the composition of the adhesive of the masking film, the coating conditions, and the like.
• the lower limit of the peel strength X between the thin film layer and the releasable base film is preferably 0.01 N / 25 mm, more preferably 0.03 N / 25 mm, and further preferably 0.05 N / 25 mm. Particularly preferably, it is 0.07 N / 25 mm.
• the upper limit of the peel strength X between the thin film layer and the releasable base film is preferably 2.0 N / 25 mm, more preferably 1.5 N / 25 mm, and further preferably 1.2 N / 25 mm. It is particularly preferably 1.0 N / 25 mm, and most preferably 0.8 N / 25 mm.
• the peel strength X between the thin film layer and the releasable base film is determined by surface treatment such as corona treatment of the releasable base film and release layer according to the composition of the thin film layer, the conditions at the time of coating, and the like. It can be adjusted by changing the composition, etc.
• the transfer target of the thin film layer is not particularly limited, but is preferably a film or a sheet, and examples thereof include a resin film, a glass film, a resin sheet, a glass plate, and a metal plate. Of these, a resin film is preferable.
• the thin film layer is a liquid crystal compound layer
• a polarizing film is transferred to produce a polarizing plate, and a retardation layer is transferred.
• the retardation layer and the polarizer, which are used as a retardation film are transferred to form a polarizing plate for circularly polarized light or an optical compensation layer, and the circularly polarized light reflecting layer and the retardation layer ( ⁇ / 4 retardation layer) are transferred to improve brightness. Examples include the use of a film.
• a circularly polarized light reflecting layer and a retardation layer in which a retardation layer is transferred to a polarizing plate of circularly polarized light or an optical compensation layer laminate for a polarizing plate. Is transferred to obtain a brightness-improving layer laminated polarizing plate.
• a phase difference is obtained for a liquid crystal display cell, for an organic EL display cell or the like in which a polarizing layer or a retardation layer and a polarizing layer are transferred and a polarizing layer is directly laminated on the liquid crystal display cell, a phase difference is obtained.
• a mode such as transferring a layer and a polarizing layer, a circularly polarized light reflecting layer, a retardation layer, and a polarizing layer to laminate an antireflection circularly polarized light layer or a circularly polarized light layer with a brightness improving layer to form an image display panel. Can be mentioned.
• the retardation layer and the polarizing layer, the circularly polarized light reflecting layer and the retarding layer and the polarizing layer are transferred to the surface cover sheet of the image display device to transfer the antireflection circularly polarized light layer and the brightness improvement.
• Examples thereof include laminating circularly polarized light layers with layers to obtain a surface cover sheet with an antireflection function for an organic EL display device and the like.
• the transfer is preferably performed by roll-to-roll, but if the transfer target is a non-long object such as an image display cell, a panel, or a surface cover sheet for reasons such as aligning the optic axis, perform the transfer with a single sheet. May be good.
• a ⁇ / 4 retardation layer made of a liquid crystal compound is provided on the release surface of the releasable base film, and a masking film is bonded to obtain a roll-shaped laminate for thin film layer transfer.
• the thin film layer transfer laminate is unwound from the roll, the masking film is peeled off, the ⁇ / 4 retardation layer and the linear polarizing plate are bonded together with an adhesive or the like, the releasable base film is peeled off, and circularly polarized light is formed. Get the board.
• the front retardation of the ⁇ / 4 retardation layer is preferably 100 to 180 nm. More preferably, it is 120 to 150 nm.
• the angle between the orientation axis (slow phase axis) of the ⁇ / 4 retardation layer and the width direction of the releasable base film (direction orthogonal to the film forming running direction of the film) is preferably 45 degrees, and there is an error. It is preferably in the range of 43 to 47 degrees including.
• the ⁇ / 4 retardation layer may be a composite ⁇ / 4 retardation layer in which the ⁇ / 4 retardation layer and the ⁇ / 2 retardation layer are combined.
• the front retardation of the ⁇ / 2 retardation layer is preferably 200 to 360 nm. More preferably, it is 240 to 300 nm.
• the ⁇ / 4 retardation layer and the ⁇ / 2 retardation layer are circularly polarizing plates and are arranged at an angle such that the retardation is ⁇ / 4 in total.
• the angle ( ⁇ ) between the orientation axis (slow phase axis) of the ⁇ / 2 retardation layer and the transmission axis of the polarizer is preferably 5 to 20 degrees, more preferably 7 to 17 degrees, and ⁇ .
• the angle between the orientation axis (slow phase axis) of the / 2 retardation layer and the orientation axis (slow phase axis) of the ⁇ / 4 retardation layer is preferably in the range of 2 ⁇ + 45 degrees ⁇ 10 degrees, more preferably 2 ⁇ + 45 degrees ⁇ 5. It is in the range of degrees, more preferably in the range of 2 ⁇ + 45 degrees ⁇ 3 degrees.
• the width direction is the transmission axis, so the width direction of the releasable base film (the direction orthogonal to the film forming running direction of the film). ) Is also preferably in the above range.
• a ⁇ / 4 retardation layer and a ⁇ / 2 retardation layer may be provided on a releasable base film and transferred thereof, or they may be transferred separately.
• a ⁇ / 4 retardation layer and a ⁇ / 2 retardation layer may be provided on the releasable base film and these may be transferred.
• a retardation layer such as a C plate layer may be provided. Also in this case, the entire retardation layer may be provided on the releasable base film and transferred, or may be transferred separately.
• the linear polarizing plate to be transferred is not particularly limited, but a linear polarizing plate in which a polarizing element protective film is provided on both sides or one side of the polarizer is preferable.
• the polarizer protects the polarizer produced by stretching a PVA-based film alone or by applying PVA to an unstretched base material such as polyester or polypropylene and stretching the entire base material.
• Examples thereof include those transferred to a film and those in which a polarizer composed of a liquid crystal compound and a dichroic dye is coated or transferred to a polarizer protective film, and all of them are preferably used.
• the polarizer protective film generally known ones such as TAC, acrylic, COP, polycarbonate, and polyester can be used. Of these, TAC, acrylic, COP, and polyester are preferable. Polyethylene terephthalate is preferable as the polyester. In the case of polyester, an in-plane retardation of 100 nm or less, particularly a zero retardation film of 50 nm or less, or a high retardation polyester film of 3000 nm to 30,000 nm is preferable.
• an adhesive As a method of pasting, conventionally known ones such as an adhesive and an adhesive can be used.
• an adhesive a polyvinyl alcohol-based adhesive, an ultraviolet curable adhesive such as acrylic or epoxy, and a heat-curable adhesive such as epoxy or isocyanate (urethane) are preferably used.
• the adhesive include acrylic, urethane, and rubber adhesives. It is also preferable to use an optical transparent adhesive sheet without an acrylic base material.
• the thickness of the circularly polarizing plate thus obtained is preferably 120 ⁇ m or less. It is more preferably 100 ⁇ m or less, further 90 ⁇ m or less, particularly 80 ⁇ m or less, and most preferably 70 ⁇ m or less.
• the retardation layer / releasable film laminate at the part where the surface masking film was peeled off was grasped together with the acrylic plate with the lower chuck of the tensile tester, and the opposite end to which the surface masking film of the biaxially stretched polyester film was bonded.
• the part was grasped by the upper chuck, and the peeling strength when peeled by 180 degrees at a speed of 300 mm / min was measured.
• An autograph (registered trademark) (AG-X) manufactured by Shimadzu Corporation was used as a testing machine, and the average value from 2 seconds to 25 seconds after the start of peeling was determined by measurement. It was carried out at 5 points of the sample, and the average value was taken as the peel strength.
• the temperature in the measurement room was 24 ° C.
• Transfer workability was evaluated from the viewpoints of peeling of the masking film during cutting and handling, ease of peeling of the masking film, and ease of peeling of the base film. ⁇ : There was no problem in either case. ⁇ : There was some problem in one of them, and attention was required for the transfer work. X: There was a problem in one of them, and the transfer work was difficult.
• a pressure esterification reaction was carried out. Then, the esterification reaction can was returned to normal pressure, and 0.014 parts by mass of phosphoric acid was added. Further, the temperature was raised to 260 ° C. over 15 minutes, and 0.012 parts by mass of trimethyl phosphate was added. Then, after 15 minutes, the dispersion treatment was carried out with a high-pressure disperser, and after 15 minutes, the obtained esterification reaction product was transferred to a polycondensation reaction can, and a polycondensation reaction was carried out under reduced pressure at 280 ° C.
• PET (X1) polyethylene terephthalate resin
• the intrinsic viscosity of PET (X1) was 0.62 dl / g, the content of the ester cyclic trimer was 1.05% by mass, and the inert particles and internally precipitated particles were substantially not contained.
• PET (X2) Manufacturing of particle-free polyester resin
• the amount of antimony trioxide added was 0.017 parts by mass, magnesium acetate tetrahydrate was added at the same time as the addition of antimony trioxide, and the Naslon filter was changed to one with a 95% cut diameter of 20 ⁇ m.
• a polyethylene terephthalate resin (PET (X2)) was obtained in the same manner as in PET (X1) except for the above.
• silica particles manufactured by Fuji Silysia Chemical Ltd.
• a viscose rayon filter having a 95% cut diameter of 30 ⁇ m.
• a polyurethane resin D-1 containing an aliphatic polycarbonate polyol as a constituent was produced by the following procedure. In a four-necked flask equipped with a stirrer, Dimroth condenser, nitrogen introduction tube, silica gel drying tube, and thermometer, 43.75 parts by mass of 4,4-diphenylmethane diisocyanate, 12.85 parts by mass of dimethylolbutanoic acid, number.
• coating liquid 1 for easy adhesive layer The following coating agents were mixed to prepare a coating liquid for an easy-adhesion layer.
• Particle B 0.07% by mass Silica sol with an average particle size of 500 nm, solid content concentration of 40% by mass
• Surfactant 0.05% by mass Silicone type, solid content concentration 100% by mass
• coating liquid 2 for easy adhesive layer The following coating agents were mixed to prepare a coating liquid for an easy-adhesion layer.
• Surfactant 0.05% by mass Silicone type, solid content concentration 100% by mass
• PET (X1) resin pellets containing no particles are dried under reduced pressure (1 Torr) at 135 ° C. for 6 hours, and then supplied to the extruder 1 to supply the opposite surface layer (back surface).
• a PET (X1) resin pellet and a polyester (PET (XSi)) resin pellet containing particles are used, and the particle content of the opposite surface layer (back surface layer) becomes a predetermined value shown in Table 1.
• the blended product in such a ratio was dried and supplied to the extruder 2 and melted at 285 ° C.
• molten polymers are each filtered through a filter medium of a stainless sintered body (nominal filtration accuracy of 10 ⁇ m particles 95% cut), laminated with a two-type two-layer confluence block, extruded into a sheet from a mouthpiece, and then extruded.
• An unstretched film was produced by winding it around a casting drum having a surface temperature of 30 ° C. and cooling and solidifying it using an electrostatic application casting method. At this time, the discharge amount of each extruder was adjusted so that the thickness of the release layer and the back surface layer became the predetermined values shown in Table 1.
• This unstretched film was guided to a tenter stretching machine, and while gripping the end of the film with a clip, it was guided to a hot air zone having a temperature of 125 ° C. and stretched 4.0 times in the width direction.
• heat fixing treatment was performed at a temperature of 210 ° C. for 10 seconds, and further relaxation treatment of 3.0% was performed.
• the PET (X1) surface is subjected to corona treatment , wound around the core with a tension of 0.5 kg / mm 2 , and uniaxially oriented PET with a film thickness of 50 ⁇ m.
• a film (width 1800 cm, length 5000 m) was obtained.
• the central portion of the obtained film was slit to a width of 50 cm to obtain a film roll (film A) having a length of about 500 m.
• the PET (X1) surface was used as the release surface.
• a film roll (film B1) was obtained in the same manner except that the PET (XSi) resin pellet was changed to PET (XCa) among the raw materials for the opposite surface layer (back surface layer). Further, the film in which the strength of the corona treatment was increased was designated as the film B2, and the film in which the corona treatment was not performed was designated as B3.
• a film roll (film C) was obtained in the same manner as in Example 2 except that the thickness ratio was changed.
• PET (X1) pellets are supplied to an extruder as a raw material for a film, extruded into a sheet from a mouthpiece, and then wound around a casting drum having a surface temperature of 30 ° C. using an electrostatic application casting method to be cooled and solidified. A stretched film was produced. Next, the coating liquid 1 for the easy-adhesion layer was applied to one side of this unstretched PET film so that the coating amount after drying was 0.12 g / m 2 , and then guided to a dryer and dried at 80 ° C. for 20 seconds.
• the unstretched film on which this coating layer was formed was guided to a tenter stretching machine, and while gripping the end of the film with a clip, it was guided to a hot air zone at a temperature of 135 ° C. and stretched four times in the width direction.
• the film was treated at a temperature of 225 ° C. for 30 seconds while maintaining the width stretched in the width direction, and then both ends of the cooled film were cut with a shear blade to form a film A on the opposite surface of the coating layer.
• corona treatment and slitting were performed to obtain a film roll (film D) having a width of 50 cm and a length of about 500 m.
• the corona-treated surface was used as the release surface.
• film E A film roll (film E) was obtained in the same manner as in film D except that PET (X2) was used as a raw material for film.
• a film F having a coating layer on both sides was obtained in the same manner as the film D except that the coating liquid 1 for an easy-adhesion layer was applied to both sides. No corona treatment was performed.
• a film G having easy-adhesive layers on both sides was obtained in the same manner as the film D except that the easy-adhesive layer coating liquid 1 was applied to one side and the easy-adhesive layer coating liquid 2 was applied to the other side.
• the coating liquid 2 coating surface for the easy-adhesion layer of this film was used as the release surface. No corona treatment was performed.
• PET (X1) resin pellets and polyester (PET (XSi)) resin pellets containing particles are blended at a ratio such that the particle content becomes a predetermined value shown in Table 1 and dried.
• the film was supplied to the extruder 2 and extruded into a sheet from a mouthpiece, and then wound around a casting drum having a surface temperature of 30 ° C. using an electrostatic application casting method to be cooled and solidified to produce an unstretched film.
• the unstretched film was guided to a tenter stretching machine, and while gripping the end portion of the film with a clip, the unstretched film was guided to a hot air zone having a temperature of 135 ° C.
• the film was treated at a temperature of 225 ° C. for 30 seconds, and then both ends of the cooled film were cut with a shear blade and corona-treated to perform uniaxial orientation with a film thickness of 50 ⁇ m.
• a PET film (width 1800 cm, length 5000 m) was obtained.
• corona treatment and slitting were performed in the same manner as in film A to obtain a film roll (film H) having a width of 50 cm and a length of about 500 m.
• the corona treatment was performed on the surface that was in contact with the casting drum when the resin was extruded, and the corona treatment surface was used as the release surface.
• a film having an easy-adhesion layer on one side was obtained by using the coating liquid 2 for an easy-adhesion layer on one side of the film H in the same manner as in the method of film D.
• a coating agent having the following composition was applied to the easy-adhesion layer surface of the obtained film and dried in a heating oven at 150 ° C. for 3 minutes to obtain Film I having a flattening coating layer. The flattening layer surface was used as the release surface.
• the following coating agents were mixed to prepare a flattening coating agent.
• the coating agent was filtered through a 2 ⁇ m filter, and the air during drying was filtered through a HEPA filter having a 95% cut diameter of 1 ⁇ m and then further filtered through a HEPA filter having a 99.9% cut diameter of 0.3 ⁇ m with high precision. I used the one. Further, the coating agent was applied to the film in a class 1,000 environment.
• the coating / drying process was performed in the same environment.
• ⁇ / 4 retardation layer 1 (Preparation of ⁇ / 4 retardation layer 1) (Formation of rubbing treatment orientation control layer) After unwinding the above film as a base film and performing corona treatment on the release surface, a coating for a rubbing treatment orientation control layer having the following composition is applied using a bar coater, dried at 80 ° C. for 5 minutes, and has a thickness of 200 nm. Formed a film. Subsequently, the surface of the obtained film was treated with a rubbing roll wrapped with a brushed nylon cloth to obtain a transfer orientation film in which a rubbing treatment orientation control layer was laminated.
• the base film is hung diagonally with respect to the rubbing roll, and the transport speed of the base film and the number of rotations of the rubbing roll are adjusted so that the rubbing direction is 45 degrees with respect to the width direction of the base film.
• Rod-shaped liquid crystal compound (LC242 manufactured by BASF) 75 parts by mass 20 parts by mass of the compound represented by the following formula (3) Trimethylolpropane Triacrylate 5 parts by mass Irgacure 379 3 parts by mass Surfactant 0.1 parts by mass Methyl ethyl ketone 250 parts by mass
• Example 13 Comparative Example 5 A ⁇ / 4 retardation layer was provided on the films B2 and B3 by the method of Preparation 2 of the following ⁇ / 4 retardation layer, and the masking films were laminated and wound. Table 1 shows the details of Examples and Comparative Examples and the evaluation results.
• ⁇ / 4 retardation layer 2 (Preparation of ⁇ / 4 retardation layer 2) (Formation of light treatment orientation control layer)
• a coating material for a photoalignment layer having the following composition was applied to one side of a base film using a bar coater and dried at 80 ° C. for 1 minute to form a film having a thickness of 150 nm. Subsequently, it was irradiated with polarized UV light to obtain a base film on which a photoalignment layer was laminated. The polarization direction of the UV light was 45 degrees with respect to the longitudinal direction of the film.
• a polarizing plate having a length of 46 cm and a width of 60 cm (a polarizing element in which iodine is adsorbed on a stretched film of polyvinyl alcohol is protected by a 60 ⁇ m thick polarizer film made of triacetyl cellulose and an 80 ⁇ m thick polarizer made of polyethylene terephthalate.
• a polarizing element in which iodine is adsorbed on a stretched film of polyvinyl alcohol is protected by a 60 ⁇ m thick polarizer film made of triacetyl cellulose and an 80 ⁇ m thick polarizer made of polyethylene terephthalate.
• Comparative Example 6 A film roll (film J) without a coating layer was obtained in the same manner as the film E except that the coating liquid 1 for the easy-adhesion layer was not applied. Table 1 shows the film thickness and the roughness parameters of the release surface. The obtained film roll had air bubbles and wrinkles, and was not suitable for use as a releasable base film.

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