Transfer film laminate and method for producing same

Abstract

Provided is a transferring film laminate which is for transferring an oriented liquid crystal compound layer, and by which the optical characteristics of the oriented liquid crystal compound layer can be inspected in the state of a film laminate on which a surface protection film remains laminated.　This transferring film laminate 1, which is for transferring an oriented crystal compound layer 3 to an object and in which a release film 2, the oriented liquid crystal compound layer 3, and a surface protection film 4 are laminated in this order, satisfies (A)-(C) below.　(A) The maximum value of the angle between the main orientation direction of the surface protection film 4 and the longitudinal direction of the transferring film laminate 1 is at most 14 degrees, or, the maximum value of the angle between the main orientation direction of the surface protection film 4 and the width direction orthogonal to the longitudinal direction of the transferring film laminate 1 is at most 14 degrees.　(B) The in-plane retardation of the release film 2 is 0-50 nm.　(C) The in-plane retardation of the surface protection film 4 is at least 100 nm.

Description

[Technical Field]

[0001] The present invention relates to a transfer film laminate for transferring an aligned liquid crystal compound layer. More specifically, the present invention relates to a transfer film laminate for transferring an aligned liquid crystal compound layer, which is used when producing a polarizing plate or retardation plate such as a circular polarizing plate having a retardation layer made of an aligned liquid crystal compound layer laminated thereon, or when producing a polarizing plate having a polarizing layer made of an aligned liquid crystal compound layer. [Background technology]

[0002] Conventionally, image display devices have arranged a circular polarizer on the viewer-side panel surface of an image display panel to reduce reflection of external light. This circular polarizer is composed of a laminate of a linear polarizer and a retardation film such as λ / 4. External light directed toward the panel surface of the image display panel is converted into linearly polarized light by the linear polarizer and then converted into circularly polarized light by the subsequent retardation film such as λ / 4. When the circularly polarized external light is reflected on the surface of the image display panel, the direction of rotation of the polarization plane is reversed. This reflected light is then converted into linearly polarized light by the retardation film such as λ / 4 in the direction blocked by the linear polarizer, and then blocked by the subsequent linear polarizer, thereby suppressing the reflected external light from escaping to the outside. To reduce reflection of external light based on this principle, a circular polarizer is used in which a retardation film such as λ / 4 is laminated to a polarizer.

[0003] As the retardation film, a retardation film made of a simple substance such as a cyclic olefin (Patent Document 1), a polycarbonate (Patent Document 2), or a stretched film of triacetyl cellulose (Patent Document 3) is used. Furthermore, a retardation film of a laminate having a retardation layer made of a liquid crystal compound on a transparent film is also used (Patent Documents 4 and 5). These documents state that the liquid crystal compound may be transferred when providing a retardation layer made of a liquid crystal compound.

[0004] Furthermore, a method for producing a retardation film by transferring a retardation layer made of a liquid crystal compound onto a transparent film is described in Patent Document 6. A method is also known in which a retardation layer made of a liquid crystal compound such as λ / 4 is provided on a transparent film by such a transfer method to produce a λ / 4 film (Patent Documents 7 and 8).

[0005] In these transfer methods, a transfer film laminate having a retardation layer provided on a release film is prepared, and the retardation layer is transferred to an object to obtain a retardation film. Usually, the transfer film laminate is prepared as a long roll, but in order to prevent the retardation layer from being scratched and to facilitate winding, a surface protective film is sometimes attached to the retardation layer before winding.

[0006] The retardation layer needs to be inspected for proper optical properties, and it has been desired to be able to inspect it in the state of a transfer film laminate. However, in the state where the surface protective film is laminated as described above, it is difficult to perform a precise inspection required for inspecting the optical properties of the retardation layer due to the influence of the retardation of the surface protective film itself. Furthermore, although it was possible to inspect the retardation layer in a state before laminating the surface protective film, there was a problem that the retardation layer surface was easily damaged due to frequent contact between the retardation layer surface and the transport roll in the path leading to the inspection process after providing the retardation layer on the release film and the path until the surface protective film is bonded after the inspection process. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-56322 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-144943 [Patent Document 3] Japanese Patent Application Laid-Open No. 2004-46166 [Patent Document 4] Japanese Patent Application Laid-Open No. 2006-243653 [Patent Document 5] Japanese Patent Application Laid-Open No. 2001-4837 [Patent Document 6] Japanese Patent Application Publication No. 4-57017 [Patent Document 7] Japanese Patent Application Laid-Open No. 2014-071381 [Patent Document 8] Japanese Patent Application Publication No. 2017-146616 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a transfer film laminate for transferring an aligned liquid crystal compound layer, which allows the optical properties of the aligned liquid crystal compound layer to be inspected while the film laminate is in the state where a surface protective film is laminated, and a method for manufacturing the same. [Means for solving the problem]

[0009] The transfer film laminate of the present invention, which has been able to achieve the above-mentioned object, and the method for producing the same, have the following gist.

[0010] [1] A transfer film laminate for transferring an oriented liquid crystal compound layer to an object, the transfer film laminate comprising a release film, an oriented liquid crystal compound layer, and a surface protective film laminated in this order, the transfer film laminate satisfying the following (A) to (C): (A) The maximum value of the angle between the main orientation direction of the surface protection film and the longitudinal direction of the transfer film laminate, measured at the following five measurement points in the width direction of the surface protection film, is 14 degrees or less, or the maximum value of the angle between the main orientation direction of the surface protection film and the width direction perpendicular to the longitudinal direction of the transfer film laminate, measured at the following five measurement points in the width direction of the surface protection film, is 14 degrees or less. <Measurement points> The five measurement points are: a first point 5 cm inward from one end of the surface protection film in the width direction of the surface protection film; a second point 5 cm inward from the other end of the surface protection film; a third point which is the midpoint between the first point and the second point; a fourth point which is the midpoint between the first point and the third point; and a fifth point which is the midpoint between the second point and the third point. (B) The release film has an in-plane retardation of 0 to 50 nm. (C) The in-plane retardation of the surface protective film is 100 nm or more.

[0011] [2] The transfer film laminate according to [1], wherein the peel strength between the aligned liquid crystal compound layer and the surface protection film is 0.005 to 2 N / 25 mm.

[0012] [3] A method for producing the transfer film laminate according to [1] or [2], laminating the release film, the aligned liquid crystal compound layer, and the surface protection film to form a transfer film laminate; A manufacturing method characterized by including, after the step of forming the transfer film laminate, a step of inspecting the alignment state of the oriented liquid crystal compound layer using at least one of the following specific optical systems (1) to (4). <Specific optical system> (1) (a) A light source is arranged on the side of the transfer film laminate facing the surface protective film, a first linear polarizer is arranged between the transfer film laminate and the light source, a second linear polarizer is arranged on the side of the transfer film laminate facing the release film, and a retardation plate is arranged between the transfer film laminate and the second linear polarizer, or (b) A light source is arranged on the side of the transfer film laminate facing the release film, a first linear polarizer is arranged between the transfer film laminate and the light source, a second linear polarizer is arranged on the side of the transfer film laminate facing the surface protection film, and a retardation plate is arranged between the transfer film laminate and the first linear polarizer. (2) A light source is arranged on the side of the transfer film laminate facing the release film or the side facing the surface protective film, and a linear polarizing plate is arranged on the side of the transfer film laminate where the light source is not arranged or between the transfer film laminate and the light source. (3) A light source is arranged on the side of the transfer film laminate facing the surface protection film, a reflector is arranged on the side of the transfer film laminate where the light source is not arranged, and a linear polarizer is arranged between the transfer film laminate and the light source. (4) A light source is arranged on the side of the transfer film laminate facing the release film or the side facing the surface protective film, a reflector is arranged on the side of the transfer film laminate where the light source is not arranged, and a linear polarizer is arranged between the transfer film laminate and the light source or between the transfer film laminate and the reflector. [Effects of the Invention]

[0013] The transfer film laminate of the present invention has the effect that, because the release film and surface protective film have predetermined properties, the optical properties of the oriented liquid crystal compound layer can be inspected while the film laminate is in the state in which the surface protective film is laminated.

[0014] Furthermore, according to the method for manufacturing a transfer film laminate of the present invention, in the step of inspecting the orientation state of the oriented liquid crystal compound layer after the step of forming a transfer film laminate by laminating a release film, an oriented liquid crystal compound layer, and a surface protection film, the orientation state of the oriented liquid crystal compound layer can be inspected while the film laminate is in its state by using the above-mentioned specific optical system. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view of a transfer film laminate according to one embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of a transfer film laminate according to another embodiment of the present invention. [Figure 3] 1 is a plan view of a surface protective film according to one embodiment of the present invention, showing measurement points for the main orientation direction of the surface protective film. [Figure 4] 1 illustrates a cross-sectional view of a specific optical system according to an embodiment of the present invention. [Figure 5] 3 illustrates a cross-sectional view of a specific optical system according to another embodiment of the present invention. [Figure 6] 10 shows a cross-sectional view of a specific optical system according to yet another embodiment of the present invention. [Figure 7] 10 shows a cross-sectional view of a specific optical system according to yet another embodiment of the present invention. [Figure 8] 10 shows a cross-sectional view of a specific optical system according to yet another embodiment of the present invention. [Figure 9] 10 shows a cross-sectional view of a specific optical system according to yet another embodiment of the present invention. [Figure 10] 10 shows a cross-sectional view of a specific optical system according to yet another embodiment of the present invention. [Figure 11] 10 shows a cross-sectional view of a specific optical system according to yet another embodiment of the present invention. [Figure 12] 10 shows a cross-sectional view of a specific optical system according to yet another embodiment of the present invention. [Figure 13] 10 shows a cross-sectional view of a specific optical system according to yet another embodiment of the present invention. [Figure 14] 10 shows a cross-sectional view of a specific optical system according to yet another embodiment of the present invention. [Figure 15] 1 shows a plan view of a sample of a transfer film laminate used in a reference example of the present specification. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention will be described below based on the embodiments with reference to the drawings. However, the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the purpose described above and below, and all such modifications are included within the technical scope of the present invention. In addition, hatching and component symbols may be omitted in each drawing for convenience. In such cases, reference should be made to the specification or other drawings. Furthermore, the dimensions of each component in the drawings may differ from the actual dimensions.

[0017] [Transfer film laminate] A transfer film laminate 1 according to an embodiment of the present invention will be described with reference to Figs. 1 to 3. Figs. 1 and 2 show cross-sectional views of the transfer film laminate 1 in a thickness direction perpendicular to the longitudinal and width directions. The transfer film laminate 1 of the present invention is intended to transfer an aligned liquid crystal compound layer 3 to an object such as another transparent resin film or a polarizing plate, and as shown in Fig. 1, a release film 2, an aligned liquid crystal compound layer 3, and a surface protective film 4 are laminated in this order, and the release film 2 and the surface protective film 4 satisfy the following (A) to (C). (A) The maximum value of the angle between the main orientation direction of the surface protection film 4 measured at the following five measurement points in the width direction (TD) of the surface protection film 4 and the longitudinal direction (MD) of the transfer film laminate 1 is 14 degrees or less, or the maximum value of the angle between the main orientation direction of the surface protection film 4 measured at the following five measurement points in the width direction (TD) of the surface protection film 4 and the width direction (TD) perpendicular to the longitudinal direction of the transfer film laminate 1 is 14 degrees or less. <Measurement points> The five measurement points are: a first point 401, which is 5 cm inward from one end of the surface protection film 4 in the width direction (TD) of the surface protection film 4; a second point 402, which is 5 cm inward from the other end of the surface protection film 4; a third point 403, which is the midpoint between the first point 401 and the second point 402; a fourth point 404, which is the midpoint between the first point 401 and the third point 403; and a fifth point 405, which is the midpoint between the second point 402 and the third point 403. (B) The in-plane retardation of the release film 2 is 0 to 50 nm. (C) The in-plane retardation of the surface protective film 4 is 100 nm or more.

[0018] The transfer film laminate 1 according to the embodiment of the present invention has a longitudinal direction (MD) and a width direction (TD) perpendicular to the longitudinal direction, and the release film 2, the aligned liquid crystal compound layer 3, and the surface protective film 4 have the same longitudinal direction (MD) and width direction (TD) as above. In addition, the film formation direction when the transfer film laminate 1, the release film 2, the aligned liquid crystal compound layer 3, and the surface protective film 4 are formed coincides with the longitudinal direction (MD).

[0019] The release film 2 may be a release substrate film 20 provided with a release layer 20a as shown in FIG. 2 , or may be a release substrate film 20 alone as long as the release substrate film 20 itself has releasability. As shown in FIG. 2 , the surface protective film 4 preferably includes at least a surface protective substrate film 40 and an adhesive layer 40a. An easy-adhesion layer may be provided on the surface of the surface protective substrate film 40 on which the adhesive layer 40a is provided. The easy-adhesion layer can be provided by applying an easy-adhesion layer coating liquid to the surface protective substrate film 40 and then drying it. For example, the easy-adhesion layer coating liquid can be prepared as a solution (dispersion) of water, alcohol, or the like, with a resin component such as polyurethane, polyester, acrylic resin, or polyolefin as the main component. The easy-adhesion layer coating liquid may further contain fine particles, a crosslinking agent, or a surfactant, as necessary. Furthermore, the surface of the surface protective substrate film 40 on which the adhesive layer 40a is provided may be subjected to corona treatment.

[0020] The surface protective film 4 may further have a release layer (not shown) on the side opposite to the adhesive layer 40a. The adhesive layer 40a or the release layer may be provided on the surface protective base film 40 by in-line or offline coating, or may be provided by co-extrusion during film production. The surface protective base film 40 may be configured as either a single layer or multiple layers by co-extrusion.

[0021] The oriented liquid crystal compound layer 3 may be provided directly on the release film 2, or may be provided on an alignment control layer which is further provided on the release film 2.

[0022] The peel strength between the surface protective film 4 and the aligned liquid crystal compound layer 3 is preferably 0.005 N / 25 mm or more, more preferably 0.01 N / 25 mm or more, even more preferably 0.03 N / 25 mm or more, and particularly preferably 0.05 N / 25 mm or more. The peel strength between the surface protective film 4 and the aligned liquid crystal compound layer 3 is preferably 2 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.

[0023] By setting the lower limit of the peel strength between the surface protective film 4 and the aligned liquid crystal compound layer 3 to the above value, problems such as inadvertent peeling of the surface protective film 4 are unlikely to occur during the winding process, unwinding process, and transfer process of the aligned liquid crystal compound layer 3. Furthermore, by setting the upper limit of the peel strength between the surface protective film 4 and the aligned liquid crystal compound layer 3 to the above value, problems such as the aligned liquid crystal compound layer 3 on the release film 2 being taken away by the surface protective film 4 when the surface protective film 4 is peeled off can be prevented. Furthermore, a high processing speed can be ensured in each process requiring peeling of the surface protective film 4 and in the process of transferring the aligned liquid crystal compound layer 3, making it easier to perform stable processing.

[0024] The peel strength between the surface protective film 4 and the aligned liquid crystal compound layer 3 can be set within the above range by selecting a pressure-sensitive adhesive having an appropriate composition suited to the aligned liquid crystal compound layer 3 .

[0025] The transfer film laminate 1, in which an oriented liquid crystal compound layer 3 is provided on a release film 2 and a surface protective film 4 is bonded to the side of the oriented liquid crystal compound layer 3 opposite the release film 2, is preferably wound up into a roll.

[0026] [Surface protection film] The surface protection film 4 according to the embodiment of the present invention is preferably stretched to impart strength, and is preferably oriented in a certain direction by stretching. The maximum value of the angle between the main orientation direction measured at the following five measurement points and the longitudinal direction of the surface protection film 4 is 14 degrees or less, or the maximum value of the angle between the main orientation direction measured at the following five measurement points and the width direction of the surface protection film 4 is 14 degrees or less. <Measurement points> The five measurement points are: a first point 401, which is 5 cm inward from one end of the surface protection film 4 in the width direction (TD) of the surface protection film 4; a second point 402, which is 5 cm inward from the other end of the surface protection film 4; a third point 403, which is the midpoint between the first point 401 and the second point 402; a fourth point 404, which is the midpoint between the first point 401 and the third point 403; and a fifth point 405, which is the midpoint between the second point 402 and the third point 403.

[0027] Since the transfer film laminate 1 according to an embodiment of the present invention has the same longitudinal direction (MD) and width direction (TD) as the surface protection film 4, the maximum value of the angle between the main orientation direction measured at the above-mentioned five measurement points and the longitudinal direction (MD) of the transfer film laminate 1 is 14 degrees or less, or the maximum value of the angle between the main orientation direction measured at the above-mentioned five measurement points and the width direction (TD) of the transfer film laminate 1 is 14 degrees or less.

[0028] A specific method for measuring the angle will be described below with reference to Fig. 3. Fig. 3 is a plan view of a surface protection film 4 according to one embodiment of the present invention, and the double-headed arrows in the surface protection film 4 indicate the main orientation direction of the surface protection film 4 measured at each location.

[0029] The transfer film laminate 1 is pulled out from the roll and the surface protective film 4 is peeled off, and five measurement points are taken in the width direction (TD) of the surface protective film 4: a first point 401 located 5 cm inward from one end of the surface protective film 4; a second point 402 located 5 cm inward from the other end of the surface protective film 4; a third point 403 located at the midpoint between the first point 401 and the second point 402, i.e., the midpoint in the width direction of the surface protective film 4; a fourth point 404 located at the midpoint between the first point 401 and the third point 403; and a fifth point 405 located at the midpoint between the second point 402 and the third point 403. The main orientation direction of the surface protective film 4 at each point is the slow axis direction of the surface protective film 4 determined using a molecular orientation meter. Next, to determine whether the main alignment direction of the entire surface protective film 4 is closer to the longitudinal direction or the width direction, the angle θ3 formed by the main alignment direction at the third point 403, which is the midpoint between the first point 401 and the second point 402, is determined to be 45 degrees or less with respect to the longitudinal direction, or greater than 45 degrees but less than 90 degrees (the main alignment direction is less than 45 degrees with respect to the width direction). If the angle is 45 degrees or less with respect to the longitudinal direction, the angles θ1 to θ5 between the main alignment direction and the longitudinal direction are measured at five points, the first point 401 to the fifth point 405. If the main alignment direction is less than 45 degrees with respect to the width direction, the angles between the main alignment direction and the width direction are measured at the five points, the first point 401 to the fifth point 405 (not shown). These angles are expressed as positive values ​​when the main alignment direction is clockwise with respect to the longitudinal or width direction, and negative values ​​when it is counterclockwise with respect to the longitudinal or width direction. In each case, the angle measured at five points (points 1 to 5) 401 to 405 is determined to be the maximum value, with the largest absolute value. Furthermore, the point with the largest angle difference from the main alignment direction measured at the five points is determined, and the angle between the two main alignment directions is determined to be the angular difference in the width direction of the main alignment direction. For example, in the case of surface protection film 4 shown in FIG. 3, if θ1 is +13 degrees, θ2 is −10 degrees, θ3 is +4 degrees, θ4 is +10 degrees, and θ5 is −4 degrees, then the maximum value is θ1, which is 13 degrees, and the angular difference in the width direction is the difference between θ1 and θ2, which is 13 degrees − (−10 degrees) = 23 degrees.

[0030] The lower limit of the maximum value of the angle between the main alignment direction of the surface protective film 4 and the longitudinal direction or width direction of the transfer film laminate 1 measured at five points, the first point 401 to the fifth point 405, is preferably 0 degrees. The upper limit of the maximum value of the angle between the main alignment direction of the surface protective film 4 and the longitudinal direction or width direction of the transfer film laminate 1 measured at five points, the first point 401 to the fifth point 405, is 14 degrees, preferably 11 degrees, more preferably 7 degrees, even more preferably 5 degrees, particularly preferably 4 degrees, and most preferably 3 degrees. In this case, the direction of the angle is not taken into consideration, and the angle shown above is an absolute value. If the maximum value of the angle between the main alignment direction of the surface protective film 4 and the longitudinal direction or width direction of the transfer film laminate 1 measured at five points, the first point 401 to the fifth point 405, is within the above range, the alignment state of the aligned liquid crystal compound layer 3 can be evaluated in the state of the film laminate with the surface protective film 4 laminated thereon. If the above range is exceeded, the linearly polarized light passing through the surface protective film 4 becomes elliptically polarized light with a small ellipticity when evaluating the alignment state of the aligned liquid crystal compound layer 3, which may make it difficult to evaluate the alignment state of the aligned liquid crystal compound layer 3. The details of the step of inspecting the aligned liquid crystal compound layer 3 will be described later.

[0031] The lower limit of the angular difference in the width direction of the main alignment direction measured at five points, the first point 401 to the fifth point 405, on the surface protective film 4 is preferably 0 degrees. The upper limit of the angular difference in the width direction of the main alignment direction measured at five points, the first point 401 to the fifth point 405, on the surface protective film 4 is preferably 7 degrees, more preferably 6 degrees, and even more preferably 4 degrees. When the angular difference in the width direction of the main alignment direction measured at five points, the first point 401 to the fifth point 405, on the surface protective film 4, is within the above range, the uniformity of the alignment state of the aligned liquid crystal compound layer 3 can be evaluated in the state of the film laminate with the surface protective film 4 laminated thereon. When the angular difference exceeds the above range, non-uniformity in transmitted light in the width direction of the transfer film laminate 1 is likely to occur due to the influence of the surface protective film 4, making it difficult to evaluate the uniformity of the alignment state of the aligned liquid crystal compound layer 3.

[0032] The reason why the orientation direction of the surface protection film 4 is distorted in the width direction is thought to be that when the film is stretched in the width direction within a tenter during production, a force that shrinks the film in the longitudinal direction acts in the stretching zone and heat setting zone.However, while the edges of the film are fixed with clips, the center of the film is not fixed, which causes a bowing phenomenon in which the film is distorted into a bow shape at the exit of the tenter.

[0033] In order to reduce the distortion in the orientation direction and achieve the above properties, the stretching temperature, stretching ratio, stretching speed, heat setting temperature, temperature in the relaxation step, ratio in the relaxation step, temperature distribution in the width direction of each temperature, etc. may be appropriately adjusted.

[0034] If the orientation direction does not fall within the above-specified range across the entire width of the produced film, it is preferable to use a portion that falls within the above-specified range, such as near the center of a stretched wide film. Furthermore, since stronger uniaxial orientation tends to reduce distortion in the orientation direction, it is also a preferred method to use weak biaxially stretched or uniaxially stretched films. In particular, weak biaxially or uniaxially stretched films, in which the longitudinal direction is the main orientation direction, are preferred.

[0035] The strength of the orientation is expressed by the refractive index n x and the refractive index in the fast axis direction, n y It can be expressed as the difference between

[0036] When the surface protection substrate film 40 is a polyethylene terephthalate (PET) film, the refractive index in the slow axis direction n x - refractive index n in the fast axis direction y The lower limit of is 0.005, more preferably 0.01, even more preferably 0.02, particularly preferably 0.03, and most preferably 0.04. If it is less than the above, stable and uniform alignment may be difficult. In addition, the refractive index n x - refractive index n in the fast axis direction y The upper limit of is preferably 0.15, more preferably 0.13, and even more preferably 0.12. If the upper limit exceeds the above range, it may be difficult to achieve the numerical value in reality.

[0037] When the surface protection substrate film 40 is a polypropylene (PP) film, the refractive index in the slow axis direction n x - refractive index n in the fast axis direction y The lower limit of is 0.0005, more preferably 0.001, even more preferably 0.002, particularly preferably 0.005, and most preferably 0.01. If it is less than the above, it may be difficult to achieve stable and uniform alignment. In addition, the refractive index n x - refractive index n in the fast axis direction y The upper limit of is preferably 0.08, more preferably 0.06, and even more preferably 0.05. If the upper limit exceeds the above range, it may be difficult to achieve the numerical value in reality.

[0038] The in-plane retardation of the surface protective film 4 is 100 nm or more, preferably 200 nm or more, more preferably 300 nm or more, and even more preferably 500 nm or more. The in-plane retardation of the surface protective film 4 is preferably 10,000 nm or less, more preferably 8,000 nm or less, and even more preferably 6,000 nm or less. The surface protective film 4 has an in-plane retardation due to being stretched as described above. If the in-plane retardation is within this range, the optical properties of the oriented liquid crystal compound layer 3 can be inspected in the state of the transfer film laminate 1 on which the surface protective film 4 is laminated, while ensuring the strength as a surface protective film.

[0039] In the case of weak biaxial stretching, it is preferable that the main orientation direction is the direction of stretching in the latter stage. In the case of uniaxial stretching, the stretching direction may be the longitudinal direction, which is the flow direction of the film production, or the width direction perpendicular to it. In the case of biaxial stretching, it may be simultaneous biaxial stretching or sequential biaxial stretching. Stretching in the longitudinal direction is preferably performed using a group of rolls with different speed differences, and stretching in the width direction is preferably performed using a tenter.

[0040] In addition, by increasing the draft ratio when the molten resin is extruded onto a cooling roll in the form of a sheet, it is possible to impart orientation to the film.

[0041] The surface protection film 4 is industrially supplied in the form of a wound film roll. The lower limit of the roll width of the surface protection film 4 is preferably 30 cm, more preferably 50 cm, even more preferably 70 cm, particularly preferably 90 cm, and most preferably 100 cm. The upper limit of the roll width of the surface protection film 4 is preferably 500 cm, more preferably 400 cm, and even more preferably 300 cm.

[0042] The lower limit of the roll length of the surface protective film 4 is preferably 100 m, more preferably 500 m, and even more preferably 1000 m. The upper limit of the roll length of the surface protective film 4 is preferably 100,000 m, more preferably 50,000 m, and even more preferably 30,000 m.

[0043] The roll width and length of the surface protection film 4 are preferably the same as the roll width and length of the transfer film laminate 1 .

[0044] Resins used for the surface protection base film 40 of the surface protection film 4 are preferably polyester (PES), polyamide (PA), polypropylene (PP), cyclic polyolefin (COP), and triacetyl cellulose (TAC), and polyester and polypropylene are more preferred. Among polyesters, polyethylene terephthalate (PET) is particularly preferred.

[0045] When the surface substrate film 40 is a stretched PET film, the lower limit of the stretching ratio in the longitudinal direction is preferably 1.5. The upper limit of the stretching ratio in the longitudinal direction is preferably 6, more preferably 5.5, and even more preferably 5. The lower limit of the stretching ratio in the width direction is preferably 1.5. The upper limit of the stretching ratio in the width direction is preferably 6, more preferably 5.5, and even more preferably 5. Stretching in the longitudinal direction is preferably performed using a continuous roll, and stretching in the width direction is preferably performed using a tenter.

[0046] The lower limit of the heat setting temperature is preferably 150°C, more preferably 170°C. If the temperature is lower than this, the heat shrinkage rate of the obtained film may not decrease. The upper limit of the heat setting temperature is preferably 240°C, more preferably 230°C. If the temperature exceeds this, it may lead to resin deterioration.

[0047] The lower limit of the width direction relaxation rate is preferably 0.1%, more preferably 0.5%. If it is less than this, the heat shrinkage rate may not decrease. The upper limit of the width direction relaxation rate is preferably 8%, more preferably 6%, and even more preferably 5%. If it exceeds this, sagging may cause poor flatness or uneven thickness.

[0048] When the surface protection substrate film 40 is a stretched PP film, it can be obtained in the same manner as above by adjusting the temperature and stretch ratio to suit PP.

[0049] Furthermore, when orientation is imparted by increasing the draft ratio, the draft ratio is preferably 1.5 times or more, more preferably 2.0 times or more, even more preferably 2.5 times or more, and particularly preferably 3.0 times or more. The draft ratio is preferably 20 times or less, more preferably 15 times or less, and even more preferably 10 times or less. If the draft ratio is too high, the thickness uniformity may deteriorate.

[0050] The surface protection film 4 may be provided with an adhesive layer 40a, which may be made of conventional adhesives such as rubber-based, acrylic-based, or polyolefin-based. 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. Examples of polyolefin-based adhesives include ethylene-propylene rubbers such as EPM and EPDM, those containing these as soft segments and polyethylene or polypropylene as hard segments, and blends of ethylene-propylene rubber with polyethylene or polypropylene. These adhesives may contain various adhesive strength regulators and stabilizers such as tackifiers, fatty acid esters, fatty acid bisamides, polyglycerin, silicone oil, and silicone resin.

[0051] Methods for providing the adhesive layer 40a include coating the surface protection base film 40 with the adhesive layer, and co-extruding the resin of the base film and the resin of the adhesive layer when forming the surface protection base film 40.

[0052] The surface protective film 4 may be provided with a release layer, and examples of the release layer include release layers made of alkyd resin, amino resin, olefin resin, long-chain acrylate copolymer acrylic resin, silicone resin, silicone-modified acrylic resin, fluororesin, etc. Methods for providing the release layer include a method of coating the surface protective base film 40 with the release layer, and a method of co-extruding the resin of the base film and the resin of the release layer when the surface protective base film 40 is formed.

[0053] The thickness of the surface protection film 4 is preferably 5 to 100 μm, more preferably 8 to 50 μm, and particularly preferably 10 to 40 μm. By setting the thickness within the above range, a surface protection film with excellent handleability and economical efficiency can be obtained. The thickness of the adhesive layer 40a is preferably 1 to 10 μm. The thickness of the release layer is preferably 0.1 to 10 μm.

[0054] [Release film] The in-plane retardation of the release film 2 is 0 to 50 nm, more preferably 0 to 30 nm, and particularly preferably 0 to 15 nm. By setting it within the above range, it becomes easy to inspect the optical properties such as the retardation and alignment direction of the oriented liquid crystal compound layer 3 in the state of the transfer film laminate 1.

[0055] The thickness of the release film 2 is preferably 5 to 100 μm, more preferably 8 to 70 μm, and particularly preferably 10 to 50 μm. By setting the thickness within the above range, the transfer film laminate 1 can be made easy to handle and economical.

[0056] There are no particular restrictions on the resin used for the release substrate film 20 of the release film 2, as long as it is a low birefringence resin that can maintain the strength required for a transfer film, but cellulose-based, polyolefin-based, and acrylic-based resins are preferred, and triacetyl cellulose (TAC) and cyclic polyolefin (COP) are particularly preferred.

[0057] The film-forming method for the release substrate film 20 is not limited as long as the in-plane retardation is within the above range, and examples thereof include a casting method in which a resin is dissolved in a solution and spread on a metal belt or the like to remove the solvent, and a melt-casting method in which the dissolved resin is extruded onto a cooling roll or a metal belt. Also, an unstretched film obtained by these methods may be stretched under conditions in which the in-plane retardation does not exceed the specified range.

[0058] The release film 2 may have a release layer 20a provided on the release substrate film 20. The resin, manufacturing method, and preferred thickness of the release layer 20a are the same as those in the case where a release layer is provided on the surface protective film 4.

[0059] [Alignment liquid crystal compound layer] The oriented liquid crystal compound layer 3 of the transfer film laminate 1 according to the embodiment of the present invention is transferred to an object to form various functional layers. For example, an absorptive polarizing layer using a liquid crystal compound and a dichroic dye, a circularly polarizing layer (circularly polarized reflective layer) using a cholesteric liquid crystal compound, and a retardation layer using a liquid crystal compound are preferred. Examples of retardation layers using a liquid crystal compound include a λ / 4 retardation layer and a λ / 2 retardation layer.

[0060] The retardation layer is formed using a material suited to each function and a molding method suited to that material, and examples of such methods include wet coating, vapor deposition, sputtering, dry film formation such as chemical vapor deposition (CVD), etc. After coating, heating or radiation curing for crosslinking may be performed.

[0061] An absorptive polarizing layer and a retardation layer using a liquid crystal compound, which are preferred embodiments of the oriented liquid crystal compound layer 3 of the present invention, will be described below.

[0062] (Aligned liquid crystal compound layer / absorptive polarizing layer) The absorptive polarizing layer preferably comprises 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.

[0063] Dichroic dyes have maximum absorption wavelengths (λ ) in the range of 300 to 700 nm. MAX) is preferred. Examples of such dichroic dyes include acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes, and anthraquinone dyes, with azo dyes being preferred. Examples of azo dyes include monoazo dyes, bisazo dyes, trisazo dyes, tetrakisazo dyes, and stilbene azo dyes, with bisazo dyes and trisazo dyes being preferred. The dichroic dyes may be used alone or in combination, but in order to adjust the color tone to an achromatic color, it is preferred to combine two or more types, and more preferably three or more types. It is particularly preferred to combine three or more types of azo compounds.

[0064] From the viewpoint of achieving 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 %, even more preferably 1.0 to 15 mass %, and particularly preferably 2.0 to 10 mass %.

[0065] The absorptive polarizing layer preferably contains a liquid crystal compound to efficiently align the dichroic dye. The liquid crystal compound is preferably a polymerizable liquid crystal compound to fix the alignment state. The polymerizable liquid crystal compound is a compound that has a polymerizable group and exhibits liquid crystallinity. The polymerizable group refers to a group that participates in a polymerization reaction, and is preferably a photopolymerizable group. Here, the photopolymerizable group refers to a group that can undergo polymerization reaction with an active radical or acid generated from a photopolymerization initiator, as described below. Examples of the polymerizable group include an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group, and an oxetanyl group, and more preferably an acryloyloxy group. The compound exhibiting liquid crystallinity may be a thermotropic liquid crystal or a lyotropic liquid crystal. Among thermotropic liquid crystals, either a nematic liquid crystal or a smectic liquid crystal may be used. Among these, a smectic liquid crystal compound is preferred, and a higher-order smectic liquid crystal compound is more preferred. When the liquid crystal layer formed by the polymerizable liquid crystal compound is in a high-order smectic phase, an absorptive polarizing layer having a higher degree of orientational order can be produced.

[0066] 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, Lub et al. Recl. Trav. Chim. Pays-Bas, 115, 321-328 (1996), and the like.

[0067] From the viewpoint of increasing the alignment 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.

[0068] The absorptive polarizing layer can be provided by applying a composition coating to the release 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 processing agent, and the like.

[0069] The composition coating may be applied onto the release film 2 or onto the orientation control layer described in detail below, and then may be dried, heated and cured as necessary.

[0070] The thickness of the polarizing layer 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.

[0071] The absorption axis direction of the polarizing layer is the alignment direction of the liquid crystal compound, and the preferred alignment direction can be determined depending on the object on which the polarizing layer is to be placed, but generally it is preferable that it be parallel, perpendicular, or 45 degrees to the longitudinal direction of the transfer film laminate.

[0072] (Alignment liquid crystal compound layer / retardation layer) The retardation layer, which is another preferred example of the oriented liquid crystal compound layer 3 of the present invention, is a layer in which a liquid crystal compound is aligned. 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.

[0073] The retardation layer may be of various types depending on 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 depending on the type of retardation layer, such as in-plane horizontal orientation, vertical orientation, tilted orientation, or orientation in which the tilt angle of the tilted orientation changes in the thickness direction, and the type of liquid crystal compound. For example, in the case of a circular polarizer, an A plate and a λ / 4 retardation layer with a retardation of 120 to 150 nm or a λ / 2 retardation layer with a retardation of 240 to 300 nm are selected.

[0074] Conventionally, polarizers have generally been made by stretching polyvinyl alcohol in the longitudinal direction and absorbing iodine or a dichroic dye of an organic compound, and the absorption axis of the polarizer is in the longitudinal direction. When the retardation layer is used alone as a λ / 4 retardation layer of a circular polarizer, the λ / 4 retardation layer is laminated so that its slow axis (orientation direction) is at 45 degrees to the absorption axis of the polarizer. Therefore, in consideration of roll-to-roll transfer processing, it is preferable that the slow axis of the λ / 4 retardation layer is at 45 degrees to the longitudinal direction of the transfer film laminate.

[0075] Furthermore, when the retardation layer of the circular polarizer is a composite λ / 4 retardation layer formed by laminating a λ / 4 retardation layer and a λ / 2 retardation layer, each retardation layer is arranged at an angle (10 to 80 degrees) to the absorption axis of the polarizer so that both retardation layers can collectively convert linearly polarized light into circularly polarized light. Taking this angle into consideration, it is preferable that each retardation layer in the transfer film laminate is also arranged at an angle to the longitudinal direction.

[0076] Examples of the retardation layer can be found in JP-A-2008-149577, JP-A-2002-303722, WO 2006 / 100830, JP-A-2015-64418, and the like.

[0077] 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, etc.

[0078] The retardation composition coating may be applied onto the release film 2 or onto the orientation control layer described in detail below, and then may be dried, heated and cured as necessary.

[0079] The thickness of the retardation layer is 0.1 to 10 μm, preferably 0.3 to 7 μm, and more preferably 0.5 to 5 μm.

[0080] (Orientation control layer) As described above, the oriented liquid crystal compound layer 3 such as a polarizing layer or a retardation layer may be provided directly on the release film 2, or an orientation control layer may be provided on the release film 2, and the oriented liquid crystal compound layer 3 may be provided on the orientation control layer. In the present invention, the polarizing layer, retardation layer, circularly polarized light reflective layer, etc. may contain an orientation control layer.

[0081] The alignment control layer 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 precision.

[0082] The alignment control layer may be any layer that can achieve the desired alignment of the oriented liquid crystal compound layer 3. Methods for providing the alignment control layer with alignment control ability include, for example, rubbing the surface, oblique deposition of an inorganic compound, and formation of a layer with microgrooves. Furthermore, a method of forming a photo-alignment control layer that orients molecules by irradiating them with polarized light to create an alignment function is also preferred. Below, a rubbed alignment control layer and a photo-alignment control layer are described as examples of preferred alignment control layers.

[0083] Examples of polymer materials used for the alignment control layer formed by rubbing treatment include polyvinyl alcohol and its derivatives, polyimide and its derivatives, acrylic resin, polysiloxane derivatives, etc. After applying a rubbing treatment alignment control layer coating liquid containing these polymer materials to a release film 2, the coating is dried by heating, etc., and then the coating surface is rubbed with a rubbing roller made of a raised cloth of fibers such as nylon, polyester, or acrylic, thereby producing an alignment control layer.

[0084] The thickness of the rubbed 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.

[0085] It is also possible to provide the surface of the release film 2 with the function of an orientation control layer by directly rubbing the release film 2 .

[0086] Another preferred example of the alignment control layer is a photo-alignment layer, which is an alignment film imparted with alignment control ability by applying a coating liquid containing a polymer or monomer having a photoreactive group and a solvent to a release film 2 and then irradiating the coating with polarized light, preferably polarized ultraviolet light. The photoreactive group is a group that exhibits liquid crystal alignment ability upon light irradiation. Specifically, it induces a photoreaction that is the origin of liquid crystal alignment ability, such as molecular alignment induction or isomerization reaction, dimerization reaction, photocrosslinking reaction, or photodecomposition reaction, upon light irradiation. Among these photoreactive groups, those that undergo dimerization or photocrosslinking reaction are preferred because they have excellent alignment control ability and maintain the liquid crystal state of the aligned liquid crystal compound 3. The photoreactive group capable of undergoing the above reaction is preferably a group containing an unsaturated bond, particularly a double bond, and particularly preferably a group containing at least one bond selected from the group consisting of a C=C bond, a C=N bond, an N=N bond, and a C=O bond.

[0087] Among these, photoreactive groups capable of undergoing photodimerization are preferred, with cinnamoyl and chalcone groups being preferred because they require a relatively small amount of polarized light irradiation for photoalignment and are also more likely to produce a photoalignment control layer with excellent thermal and temporal stability. Furthermore, polymers having photoreactive groups are particularly preferred, with cinnamoyl groups at the end of the polymer side chain forming a cinnamic acid structure. Examples of main chain structures include polyimide, polyamide, (meth)acrylic, and polyester.

[0088] Specific examples of the optical alignment control layer include those described in JP 2006-285197 A, JP 2007-76839 A, JP 2007-138138 A, JP 2007-94071 A, JP 2007-121721 A, JP 2007-140465 A, JP 2007-156439 A, JP 2007-133184 A, and JP 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.

[0089] By irradiating the photo-alignment layer obtained by the above method with polarized light in a predetermined oblique direction, a photo-alignment layer having the ability to control alignment in a predetermined direction can be obtained.

[0090] The oriented liquid crystal compound layer 3 may be a single layer or may be a multi-layer structure of two or more layers. When the oriented liquid crystal compound layer 3 is a multi-layer structure, it is preferable to provide an alignment control layer on a previously provided oriented liquid crystal compound layer, and then provide a next oriented liquid crystal compound layer on top of that. In addition, an interlayer protective layer such as a radiation-curable acrylic resin layer may be provided between or on the oriented liquid crystal compound layers.

[0091] [Manufacturing method] The present invention also provides a method for manufacturing the transfer film laminate 1. The manufacturing method according to an embodiment of the present invention will be described with reference to Figs. 4 to 14. The manufacturing method of the present invention includes the steps of forming the transfer film laminate 1 by laminating a release film 2, an aligned liquid crystal compound layer 3, and a surface protective film 4, and, after the step of forming the transfer film laminate 1, inspecting the alignment state of the aligned liquid crystal compound layer 3 using at least one of the following specific optical systems (1) to (4). <Specific optical system> The specific optical system of the present invention is based on the following technical concept and is intended to perform inspection without disturbing the polarization state. -Do not place a surface protection film on the optical path where it is necessary to maintain the circular polarization characteristics. When placing a surface protection film in an optical path portion where linear polarization properties must be maintained, place it so that the vibration direction of the linearly polarized light is parallel or perpendicular to the main orientation axis of the surface protection film. Specifically, the following (1) to (4) can be mentioned. (1)(a) A light source 5 is arranged on the side of the transfer film laminate 1 facing the surface protective film 4, a first linear polarizer 61 is arranged between the transfer film laminate 1 and the light source 5, a second linear polarizer 62 is arranged on the side of the transfer film laminate 1 facing the release film 2, and a retardation plate 7 is arranged between the transfer film laminate 1 and the second linear polarizer 62, or (b) A light source 5 is arranged on the side of the transfer film laminate 1 facing the release film 2, a first linear polarizer 61 is arranged between the transfer film laminate 1 and the light source 5, a second linear polarizer 62 is arranged on the side of the transfer film laminate 1 facing the surface protective film 4, and a retardation plate 7 is arranged between the transfer film laminate 1 and the first linear polarizer 61. (2) A light source 5 is arranged on the side of the transfer film laminate 1 facing the release film 2 or the side facing the surface protective film 4, and a linear polarizer 6 is arranged on the side of the transfer film laminate 1 where the light source 5 is not arranged or between the transfer film laminate 1 and the light source 5. (3) A light source 5 is arranged on the side of the transfer film laminate 1 facing the surface protective film 4, a reflector 8 is arranged on the side of the transfer film laminate 1 where the light source 5 is not arranged, and a linear polarizer 6 is arranged between the transfer film laminate 1 and the light source 5. (4) A light source 5 is arranged on the side of the transfer film laminate 1 facing the release film 2 or the side facing the surface protective film 4, a reflector 8 is arranged on the side of the transfer film laminate 1 where the light source 5 is not arranged, and a linear polarizer 6 is arranged between the transfer film laminate 1 and the light source 5 or between the transfer film laminate 1 and the reflector 8.

[0092] According to the manufacturing method of the present invention, after forming a transfer film laminate 1 by laminating a release film 2, an oriented liquid crystal compound layer 3, and a surface protective film 4, the alignment state of the oriented liquid crystal compound layer 3 can be inspected in the state of the film laminate as it is.

[0093] When the aligned liquid crystal compound layer 3 is a retardation layer 31, the alignment state of the liquid crystal compound layer 3 is preferably inspected by the above-mentioned specific optical system (1) or (3), and when the aligned liquid crystal compound layer 3 is a polarizing layer 32, the alignment state of the aligned liquid crystal compound layer 3 is preferably inspected by the above-mentioned specific optical system (2) or (4). The specific optical systems (1) to (4) will be described below with reference to Figs. 4 to 14.

[0094] The type of light source 5 is not particularly limited, but it is preferably a surface-emitting light source that uses a white LED as a light source. While the components are depicted as being spaced apart in FIGS. 4 to 14, they may also be in close contact with each other. For example, the light source 5 may be placed horizontally on a flat surface with its light-emitting surface facing upward, and the components may be stacked on top of it in the order shown in FIGS. 4 to 14. Furthermore, the linear polarizer 6 and the retarder 7 may be incorporated into the light source 5 or the detector (not shown).

[0095] The specific optical system (1)(a) will be described with reference to Fig. 4. In the embodiment shown in Fig. 4, a light source 5 is disposed on the side of the transfer film laminate 1 facing the surface protection film 4. A first linear polarizer 61 is disposed between the transfer film laminate 1 and the light source 5, which allows linearly polarized light having an electric field oscillation direction in the main alignment direction of the surface protection film 4 or a direction perpendicular to the main alignment direction, or parallel to the longitudinal direction or width direction of the transfer film laminate 1 to be irradiated onto the transfer film laminate 1 from the surface protection film 4 side. A second linear polarizer 62 is disposed on the side of the transfer film laminate 1 facing the release film 2, and a retardation plate 7 is disposed between the transfer film laminate 1 and the second linear polarizer 62.

[0096] When the retardation plate 7 cancels the retardation caused by the aligned liquid crystal compound layer 3, the second linear polarizer 62 is preferably arranged so as to satisfy a crossed Nicol relationship with the first linear polarizer 61.

[0097] Furthermore, when the retardation plate 7 adds a further retardation to the retardation generated by the oriented liquid crystal compound layer 3 and converts the linearly polarized light having a vibration direction of 90 degrees to the linearly polarized light that has passed through the first linear polarizer 61, it is preferable that the second linear polarizer 62 is arranged so as to satisfy a parallel Nicol relationship with the first linear polarizer 61.

[0098] In the above optical system, light emitted from the light source 5 is linearly polarized by the first linear polarizer 61 and enters the transfer film laminate 1 from the surface protection film 4 side. The incident light is elliptically polarized by the oriented liquid crystal compound layer 3 of the transfer film laminate 1, but the light that passes through the retardation plate 7 becomes linearly polarized. When this light passes through the second linear polarizer 62, if the retardation layer of the oriented liquid crystal compound layer 3 has an orientation that generates the designed retardation, it will enter an extinction state. If light leakage is observed without entering an extinction state at this time, it will be understood that the retardation layer of the oriented liquid crystal compound layer 3 does not have the designed orientation.

[0099] Thus, the retarder 7 converts light passing through the aligned liquid crystal compound layer 3 into linearly polarized light when the retardation layer of the aligned liquid crystal compound layer 3 is as designed, but does not convert the light into linearly polarized light when the retardation layer of the aligned liquid crystal compound layer 3 is not as designed. Therefore, the second linear polarizer 62 does not cause the light to be extinguished. Therefore, by checking whether the extinction state is present, it is possible to inspect whether the retardation layer of the aligned liquid crystal compound layer 3 has the designed alignment. According to the manufacturing method of the present invention, the main alignment direction of the surface protective film 4 forms an angle of a predetermined value or less with the longitudinal direction or width direction of the transfer film laminate 1. Therefore, after forming the transfer film laminate 1, it is possible to inspect the alignment state of the aligned liquid crystal compound layer 3 while the film laminate is in its laminated state. Furthermore, because linearly polarized light is incident on the surface protective film 4, even if the surface protective film 4 has a retardation of a predetermined value or more, it is possible to inspect the alignment state of the aligned liquid crystal compound layer 3 while the film laminate is in its laminated state without being affected by the surface protective film 4.

[0100] The specific optical system (1)(b) will be described with reference to Fig. 5. In the embodiment shown in Fig. 5, a light source 5 is arranged on the side of the transfer film laminate 1 facing the release film 2. A first linear polarizer 61 is arranged between the transfer film laminate 1 and the light source 5, and a retardation plate 7 is arranged between the first linear polarizer 61 and the transfer film laminate 1. A second linear polarizer 62 is arranged on the side of the transfer film laminate 1 facing the surface protection film 4.

[0101] Even in this case, if the oriented liquid crystal compound layer 3 cancels the phase difference caused by the retardation plate 7, it is preferable that the second linear polarizer 62 is arranged to satisfy a crossed Nicol relationship with the first linear polarizer 61.

[0102] Furthermore, when the aligned liquid crystal compound layer 3 adds a phase difference to the phase difference generated by the retardation plate 7 to convert the linearly polarized light having a vibration direction of 90 degrees relative to the linearly polarized light that has passed through the first linear polarizer 61, it is preferable that the second linear polarizer 62 is disposed so as to satisfy a parallel Nicol relationship with the first linear polarizer 61. As a result, elliptically polarized light generated by the retardation plate 7 is incident on the aligned liquid crystal compound layer 3, but light that is incident on the surface protective film 4 becomes linearly polarized. The light that has passed through the surface protective film 4 is extinguished by the second linear polarizer 62, and if the aligned liquid crystal compound layer 3 has an orientation that generates a designed phase difference, an extinction state is observed. If the orientation is not as designed, light leakage is observed, and therefore the alignment state of the aligned liquid crystal compound layer 3 can be inspected.

[0103] 5, since the main orientation direction of the surface protective film 4 has an angle of a predetermined value or less with respect to the longitudinal direction or width direction of the transfer film laminate 1, it becomes possible to inspect the orientation state of the aligned liquid crystal compound layer 3 in the state of the film laminate after forming the transfer film laminate 1. Moreover, since linearly polarized light converted by the aligned liquid crystal compound layer 3 is incident on the surface protective film 4, even if the surface protective film 4 has a retardation of a predetermined value or more, it becomes possible to inspect the orientation state of the aligned liquid crystal compound layer 3 in the state of the laminate without being affected by the retardation.

[0104] The light emitted from the light source 5 through the first linear polarizer 61 is preferably linearly polarized light parallel or perpendicular to the main alignment direction of the surface protective film 4. "Parallel" to the main alignment direction of the surface protective film 4 is preferably in the range of -10 to +10 degrees, more preferably -7 to +7 degrees, even more preferably -5 to +5 degrees, particularly preferably -3 to +3 degrees, and most preferably -2 to +2 degrees. "Perpendicular" to the main alignment direction of the surface protective film 4 is preferably 80 to 100 degrees, more preferably 83 to 97 degrees, even more preferably 85 to 95 degrees, particularly preferably 87 to 93 degrees, and most preferably 88 to 92 degrees. If the angle exceeds the above range, polarized light incident on or passing through the retardation layer of the aligned liquid crystal compound layer 3 is affected by the retardation of the surface protective film 4 and disturbed, which may prevent accurate inspection.

[0105] Although the angle of the linearly polarized light to be irradiated may be adjusted each time in accordance with the main orientation direction of the surface protective film 4, this makes the inspection cumbersome. Therefore, it is also preferable to perform the inspection by fixing the irradiated linearly polarized light parallel or perpendicular to the longitudinal direction of the surface protective film 4. Here, "parallel" or "perpendicular" has the same meaning as above.

[0106] Furthermore, it is also possible to set up a plurality of linear polarizers and retardation plates with different angles and retardation, and to detect in which direction and by how much the retardation or alignment direction of the retardation layer has shifted.

[0107] Of the above, the embodiment of FIG. 4 in which the light source 5 is disposed on the surface protection film 4 side of the transfer film laminate 1 and linearly polarized light is irradiated from the surface protection film 4 side is preferred because the optical system can be easily adjusted.

[0108] When the aligned liquid crystal compound layer 3 is a polarizing layer 32, it is preferable to inspect the alignment state of the aligned liquid crystal compound layer 3 by the above-mentioned specific optical system (2). The specific optical system (2) will be described below with reference to Figs. 6 to 9.

[0109] A light source 5 is disposed on the side of the transfer film laminate 1 facing the release film 2 or the side facing the surface protective film 4. A linear polarizer 6 that satisfies a crossed Nicol relationship with the polarizing layer of the oriented liquid crystal compound layer 3 is disposed on the side of the transfer film laminate 1 where the light source 5 is not disposed or between the transfer film laminate 1 and the light source 5.

[0110] In the embodiment of FIG. 6 , the light source 5 is disposed on the side of the transfer film laminate 1 facing the surface protective film 4, and the linear polarizer 6 is disposed on the side of the transfer film laminate 1 opposite to the light source 5. As a result, unpolarized light (natural light) emitted from the light source irradiates the transfer film laminate 1, and light polarized by the polarizing layer of the aligned liquid crystal compound layer 3 enters the linear polarizer 6. Since the linear polarizer 6 satisfies a crossed Nicol relationship when the polarizing layer of the aligned liquid crystal compound layer 3 is changed as designed, the linear polarizer 6 will be in an extinction state when the polarizing layer of the aligned liquid crystal compound layer 3 is as designed, but will not be in an extinction state when the polarizing layer of the aligned liquid crystal compound layer 3 is not as designed. Therefore, by checking whether or not the extinction state is present, it is possible to inspect whether the polarizing layer of the aligned liquid crystal compound layer 3 has the designed orientation. Thus, according to the manufacturing method of the present invention, after forming the transfer film laminate 1, it is possible to inspect the alignment state of the aligned liquid crystal compound layer 3 while it is still in the laminate state.

[0111] In the embodiment of Fig. 7, a linear polarizer 6 is disposed between the transfer film laminate 1 and the light source 5. The principle is the same as in Fig. 6, and in the case of Fig. 7, light linearly polarized by the linear polarizer 6 is incident on the transfer film laminate 1, but the linear polarizer 6 is arranged to satisfy a crossed Nicol relationship with the polarizing layer of the aligned liquid crystal compound layer 3, so that if the polarizing layer of the aligned liquid crystal compound layer 3 is as designed, the light will be extinct, and if it is not as designed, the light will not be extinct and light leakage will be detected.

[0112] 8 and 9, the case where the light source 5 is arranged on the release film 2 side of the transfer film laminate 1 is similar to the case of the above-mentioned Figures 6 and 7. In Figure 8, the transfer film laminate 1 is irradiated with unpolarized light (natural light), and in Figure 9, the transfer film laminate 1 is irradiated with linearly polarized light from a linear polarizer 6, and the extinction state is examined, thereby enabling the polarizing layer of the oriented liquid crystal compound layer 3 to be inspected.

[0113] 7 and 8, the light incident on the surface protective film 4 is preferably linearly polarized light parallel or perpendicular to the main orientation direction of the surface protective film 4. Here, the ranges of parallel and perpendicular are as described above. Furthermore, as described above, it is preferable to inspect the surface protective film 4 with the irradiated linearly polarized light fixed parallel or perpendicular to the longitudinal direction of the surface protective film 4.

[0114] Therefore, the embodiments of Figures 7 and 8 are preferably applied to a transfer film laminate 1 in which the absorption axis of the polarizer of the oriented liquid crystal compound layer 3 is parallel or perpendicular to the longitudinal direction of the surface protective film 4.

[0115] 6 and 9 are not limited by the direction of the absorption axis of the polarizer in the aligned liquid crystal compound layer 3. Therefore, the transfer film laminate 1 in which the absorption axis of the polarizer in the aligned liquid crystal compound layer 3 is at an angle other than parallel or perpendicular, such as 45 degrees, to the longitudinal direction of the surface protective film 4, is preferably the embodiment in Fig. 6 or 9. Note that the transfer film laminate 1 in which the absorption axis of the polarizer in the aligned liquid crystal compound layer 3 is parallel or perpendicular to the longitudinal direction of the surface protective film 4 may be any of the embodiments in Fig. 6 to Fig. 9.

[0116] Furthermore, by providing a plurality of polarizing plates with different angles, it is possible to detect in which direction and to what extent the alignment direction of the oriented liquid crystal compound layer 3 has shifted.

[0117] Of the above, when irradiating non-polarized light (natural light), it is preferable to irradiate from the surface protection film 4 side (embodiment shown in Figure 6), because there is no birefringent layer between the polarizer of the oriented liquid crystal compound layer 3 and the linear polarizing plate 6, and the extinction state in crossed Nicols can be measured more precisely. When irradiating linearly polarized light, it is preferable to irradiate from the release film 2 side (embodiment shown in Figure 9).

[0118] In the above, inspection using a transmission optical system has been described, but a reflection optical system (specific optical systems (3) and (4)) will be described with reference to FIGS.

[0119] The embodiment of Fig. 10 is preferably used when the transfer film laminate 1 is used to transfer a λ / 4 retardation layer 31. In the embodiment of Fig. 10, a light source 5 is arranged on the surface protection film 4 side of the transfer film laminate 1, and a reflector 8 is arranged on the release film 2 side. The reflector 8 is preferably a specularly reflective plate such as a mirror-finished aluminum plate, stainless steel plate, aluminum-deposited glass, or silver-deposited glass. A linear polarizer 6 is arranged between the transfer film laminate 1 and the light source 5. The absorption axis of the linear polarizer 6 is arranged in a relationship with the λ / 4 retardation layer 31 of the aligned liquid crystal compound layer 3 to form a circular polarizer.

[0120] Unpolarized light (natural light) emitted from the light source 5 is converted into linearly polarized light by the linear polarizer 6, and is further converted into circularly polarized light by the λ / 4 retardation layer 31. This circularly polarized light is reflected by the reflector as circularly polarized light with the opposite rotation. The reflected circularly polarized light is converted by the λ / 4 retardation layer 31 into linearly polarized light whose vibration direction differs by 90 degrees from the original linearly polarized light, and reaches the linear polarizer 6. If the oriented liquid crystal compound layer 3 has the designed retardation, the linearly polarized light that reaches it cannot pass through the linear polarizer 6 and is extinguished; if it does not have the designed retardation, the extinguishing state does not occur and light leakage is detected.

[0121] In the embodiment of Fig. 10, the light emitted from the light source 5 through the linear polarizer 6 is preferably linearly polarized light parallel or perpendicular to the main alignment direction of the surface protective film 4. Here, the ranges of parallel and perpendicular are as described above. Furthermore, as described above, it is also preferable to inspect the surface protective film 4 with the irradiated linearly polarized light fixed parallel or perpendicular to the longitudinal direction of the surface protective film 4.

[0122] In addition, by providing a plurality of polarizing plates with different angles, it is possible to detect the direction and the degree of deviation of the alignment direction of the oriented liquid crystal compound layer 3. Furthermore, by providing a plurality of retardation plates with a retardation of about 5 to 50 nm between the transfer film laminate 1 and the reflector 8, it is also possible to detect the degree of deviation of the retardation of the oriented liquid crystal compound layer 3.

[0123] The embodiments of FIGS. 11 to 14 are suitably used when the aligned liquid crystal compound layer 3 is the polarizing layer 32. In the embodiment of FIGS.

[0124] A light source 5 is disposed on the side of the transfer film laminate 1 facing the release film 2 or the side facing the surface protective film 4. A reflector 8 is provided on the side of the transfer film laminate 1 where the light source 5 is not disposed. The reflector 8 may be a specular reflector or a diffuse reflector. A diffuse reflector is preferred in that it allows measurement to be performed while avoiding surface reflections from the transfer film laminate 1 or the linear polarizer 6 during detection. Examples of diffuse reflectors include a foamed resin sheet, a white pigment-containing resin sheet, a plate coated with a white pigment-containing paint, and a white ceramic plate. A linear polarizer 6 is disposed between the transfer film laminate 1 and the reflector 8 or between the transfer film laminate 1 and the light source 5. The polarizing layer of the aligned liquid crystal compound layer 3 and the linear polarizer 6 are preferably in a crossed Nicol relationship.

[0125] In the embodiment of FIG. 11 , the light source 5 is disposed on the side of the transfer film laminate 1 facing the surface protective film 4, and the reflector 8 and linear polarizer 6 are disposed on the side of the transfer film laminate 1 where the light source 5 is not disposed. As a result, unpolarized light (natural light) emitted from the light source 5 is irradiated onto the transfer film laminate 1, and light polarized by the polarizing layer of the aligned liquid crystal compound layer 3 is incident on the linear polarizer 6. If the polarizing layer of the aligned liquid crystal compound layer 3 is as designed, the linear polarizer 6 will cause an extinction state. However, if the polarizing layer of the aligned liquid crystal compound layer 3 is not as designed, the extinction state will not occur. In the extinction state, almost no light reaches the reflector 8, and even the very small amount of light that reaches the reflector 8 and is reflected is in an extinction state when observed from the light source side because the linear polarizer 6 and the polarizing layer of the aligned liquid crystal compound layer 3 are in a crossed Nicol configuration. On the other hand, if the extinction state is insufficient, light reaches the reflector 8, and the reflected light also passes through the linear polarizer 6 and the polarizing layer of the aligned liquid crystal compound layer 3, resulting in light leakage. In this way, by checking whether or not the extinction state exists, it is possible to inspect whether the polarizing layer of the oriented liquid crystal compound layer 3 has the orientation as designed, and it is possible to inspect the orientation state of the oriented liquid crystal compound layer 3 while it is in the laminate state.

[0126] In the embodiment of Fig. 12, a linear polarizer 6 is disposed between the transfer film laminate 1 and the light source 5. The principle is the same as in Fig. 11, and in the case of Fig. 12, light linearly polarized by the linear polarizer 6 is incident on the transfer film laminate 1, but the linear polarizer 6 is arranged to satisfy a crossed Nicol relationship with the polarizing layer of the aligned liquid crystal compound layer 3, so that if the polarizing layer of the aligned liquid crystal compound layer 3 is as designed, the light will be extinct, and if it is not as designed, the light will not be extinct and light leakage will be detected.

[0127] 13 and 14, when the light source 5 is arranged on the release film 2 side of the transfer film laminate 1, the same applies as in the above-mentioned Figures 11 and 12. In Figure 13, unpolarized light (natural light) is irradiated onto the transfer film laminate 1, and in Figure 14, linearly polarized light from a linear polarizer 6 is irradiated onto the transfer film laminate 1, and the extinction state is examined, thereby enabling the polarizing layer of the oriented liquid crystal compound layer 3 to be inspected.

[0128] 12 and 13, the light incident on the surface protective film 4 is preferably linearly polarized light parallel or perpendicular to the main orientation direction of the surface protective film 4. Here, the ranges of parallel and perpendicular are as described above. Furthermore, as described above, it is also preferable to inspect the surface protective film 4 with the linearly polarized light fixed parallel or perpendicular to the longitudinal direction of the surface protective film 4.

[0129] Furthermore, by providing a plurality of polarizing plates with different angles, it is possible to detect in which direction and by how much the alignment direction of the oriented liquid crystal compound layer 3 has shifted.

[0130] The embodiments of FIGS. 12 and 13 are preferably applied to a transfer film laminate 1 in which the absorption axis of the polarizer of the aligned liquid crystal compound layer 3 is parallel or perpendicular to the longitudinal direction of the surface protective film 4.

[0131] 11 and 14 are not limited by the direction of the absorption axis of the polarizer of the aligned liquid crystal compound layer 3. Therefore, the transfer film laminate 1 in which the absorption axis of the polarizer of the aligned liquid crystal compound layer 3 is at an angle other than parallel or perpendicular, such as 45 degrees, with respect to the longitudinal direction of the surface protective film 4 is preferably the embodiment of Fig. 11 or 14. Note that the transfer film laminate 1 in which the absorption axis of the polarizer of the aligned liquid crystal compound layer 3 is parallel or perpendicular to the longitudinal direction of the surface protective film 4 may be any of the embodiments of Fig. 11 to 14.

[0132] Of the above, when irradiating non-polarized light (natural light), it is preferable to irradiate from the surface protection film 4 side (embodiment shown in Figure 11), because there is no birefringent layer between the polarizer of the oriented liquid crystal compound layer 3 and the linear polarizer 6, and the extinction state in crossed Nicols can be measured more precisely. When irradiating linearly polarized light, it is preferable to irradiate from the release film 2 side (embodiment shown in Figure 14).

[0133] This application claims the benefit of priority to Japanese Patent Application No. 2019-148469, filed on August 13, 2019. The entire content of the specification of Japanese Patent Application No. 2019-148469, filed on August 13, 2019, is incorporated herein by reference. [Example]

[0134] 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 practiced with appropriate modifications within the scope of the above and below-described aims, all of which are included in the technical scope of the present invention.

[0135] The evaluation of each property in the examples was carried out by the following methods.

[0136] (1) Angle of the main orientation direction The transfer film laminate was pulled from the roll and the surface protection film was peeled off. The orientation direction was determined at five points: a first point 5 cm inward from one end of the surface protection film; a second point 5 cm inward from the other end of the surface protection film; a third point midway between the first and second points; a fourth point midway between the first and third points; and a fifth point midway between the second and third points. The main orientation direction was determined as the slow axis direction of the surface protection film using a molecular orientation meter (MOA-6004, manufactured by Oji Scientific Instruments Co., Ltd.). Next, the main orientation direction of the entire surface protection film at the third point, i.e., the midpoint in the width direction of the surface protection film, was examined to determine whether it was closer to the machine direction (MD) or the transverse direction (TD). If the main orientation direction of the entire surface protection film was closer to the machine direction, the angle between the orientation direction and the machine direction was determined at each of the five points. On the other hand, when the main orientation direction of the entire surface protection film was close to the width direction, the angle between the main orientation direction and the width direction was determined at each of the five locations.

[0137] These angles were expressed as positive values ​​when the main orientation direction was clockwise relative to the longitudinal direction or width direction, and negative values ​​when it was counterclockwise. In each case, the value at the point with the largest absolute value among the angles measured at five points was taken as the maximum value. In addition, among the main orientation axes measured at five points, the point with the main orientation axis that had the largest angle difference from the main orientation axis at the point with the maximum value was determined, and the angle between the two main orientation axes was taken as the angle difference in the width direction of the main orientation axes.

[0138] (2) Refractive index of surface protection film A 4 cm × 2 cm rectangle was cut out as a measurement sample so that the slow axis direction determined in (1) above was parallel to the long side. The refractive index of this sample was measured using two perpendicular axes (refractive index in the slow axis direction: n x , fast axis (refractive index in the direction perpendicular to the slow axis direction): n y ) was determined using an Abbe refractometer (manufactured by Atago Co., Ltd., NAR-4T, measurement wavelength 589 nm).

[0139] (3) Film thickness Measurement was carried out using an electric micrometer (Militron 1245D, manufactured by Fineruf Co., Ltd.).

[0140] (4) In-plane retardation As with (2), the refractive index of the release film is n x , n y Find (n x -n y ) × d (film thickness: nm) was taken as the in-plane retardation. When the film was optically isotropic and the orientation direction was not determined, the film was cut so that the width direction of the film was parallel to the long side direction of the rectangular sample.

[0141] (5) Peel strength between the alignment liquid crystal compound layer and the surface protection film A laminate of surface protection film / aligned liquid crystal compound layer (λ / 4 retardation layer) / release film (TAC film) was cut to a width of 25 mm and a length of 160 mm to prepare a sample. The length direction of the sample was the width direction of the TAC film. An NT cutter L type was used for cutting.

[0142] The TAC film side of the sample was attached to an acrylic plate of the same width and length as the 1 mm-thick sample using double-sided tape. The surface protective film was peeled off from a section approximately 20 mm from one end of the sample, and a biaxially oriented polyester film measuring 25 mm in width, 160 mm in length, and 50 μm in thickness was attached to the peeled section using double-sided tape. The oriented liquid crystal compound layer (λ / 4 retardation layer) / release film (TAC film) laminate was held together with the acrylic plate in the lower chuck of a tensile tester, and the edge opposite the biaxially oriented polyester film surface protective film was held in the upper chuck. The peel strength was measured at a 180° peel angle at a speed of 300 mm / min. The tester used was a Shimadzu Autograph® AG-X. The average strength was calculated from 2 seconds to 25 seconds after peeling began. Measurements were performed at five points on the sample, and the average was used as the peel strength. The temperature in the measurement chamber was 24°C. The samples were left in a room at 24°C and a relative humidity of 50% for 24 hours after the surface protection film was attached.

[0143] (6) Light leakage A first linear polarizer was placed on a surface-emitting light source using a white LED containing a yellow phosphor. A laminate consisting of a surface protective film, an aligned liquid crystal compound layer (λ / 4 retardation layer), and a release film (TAC film) was placed on top of the first linear polarizer, with the surface protective film facing the first linear polarizer and the absorption axis direction of the first linear polarizer parallel to the longitudinal direction of the sample laminate. A retardation plate (λ / 4 film) made of a stretched cyclic polyolefin film was then placed on top of the first linear polarizer, with its main axis oriented at 45 degrees to the absorption axis of the first polarizer and perpendicular to the slow axis direction of the λ / 4 retardation layer (the direction in which the λ / 4 retardation of the sample laminate was canceled by the retardation of the retardation plate (λ / 4 film)). A second linear polarizer was then placed on top of the second linear polarizer, with its absorption axis perpendicular to that of the first linear polarizer (so that they were in a crossed Nicol relationship). The extinction state was observed in this state. Specifically, the extinction state of the brightest part of the sample laminate was compared with that of the standard sample according to the following criteria: The standard sample was a λ / 4 retardation layer / release film (TAC film) laminate without a surface protective film attached. ◎: The quenching state was equivalent to that of the standard sample. ○: Slightly more transmitted light than the standard sample was observed. △: Light transmitted through the standard sample was observed, but it was possible to evaluate the phase difference state. ×: The transmitted light was greater than that of the standard sample, making it difficult to evaluate the phase difference state.

[0144] (7) Brightness uniformity Under the same conditions as in (6) above, the uniformity of the extinction state within the sample laminate was evaluated according to the following criteria. ⊚: The brightness was almost the same over the entire sample laminate. ○: There was a slight difference in brightness. △: There was a small difference in brightness. ×: The difference in brightness was large.

[0145] (8) Handling The ease of cutting out a sample for measuring peel strength and setting the sample on the measuring device was judged according to the following criteria. ◯: During normal handling, the surface protection film did not peel off during cutting or setting. △: The surface protection film sometimes peeled off during cutting or setting, making it necessary to remake the sample. ×: The surface protection film peeled off with even a slight force when cutting out or setting, and it was necessary to make many samples again in order to perform the measurement.

[0146] (9) Ease of peeling A laminate of surface protection film / aligned liquid crystal compound layer (λ / 4 retardation layer) / release film (TAC film) was cut into an A4 size piece, and the surface protection film was peeled off by hand from a corner in a diagonal direction at a constant speed over about 3 seconds. The ease of peeling was evaluated according to the following criteria. ○: Smooth peeling was possible within 3 seconds. △: Some force was required for peeling, but peeling was possible within 3 seconds. ×: Peeling required force, and peeling within 3 seconds was difficult.

[0147] (10) Damage to the alignment liquid crystal compound layer After the evaluation of the ease of peeling (9) above, the laminate of the aligned liquid crystal compound layer (λ / 4 retardation layer) / release film (TAC film) was visually observed in the same manner as in the evaluation of light leakage to see if the λ / 4 retardation layer was taken up by the surface protective film and was missing. ◯: The entire surface was in an extinction state, and there was no defect in the λ / 4 retardation layer. x: There were some areas that were not extinguished, and there were defective areas in the λ / 4 retardation layer.

[0148] Surface protection film manufacturing [Manufacturing of easy-adhesion layer] (Manufacturing of polyurethane resin) Polyurethane resin D-1, composed of an aliphatic polycarbonate polyol, was produced by the following procedure. 43.75 parts by mass of 4,4-diphenylmethane diisocyanate, 12.85 parts by mass of dimethylolbutanoic acid, 153.41 parts by mass of polyhexamethylene carbonate diol with a number-average molecular weight of 2000, 0.03 parts by mass of dibutyltin dilaurate, and 84.00 parts by mass of acetone as a solvent were added to a four-neck flask equipped with a stirrer, Dimroth condenser, nitrogen inlet tube, silica gel drying tube, and thermometer. The mixture was stirred at 75°C for 3 hours under a nitrogen atmosphere, and it was confirmed that the reaction solution had reached the required amine equivalent. Next, the reaction solution was cooled to 40°C, and 8.77 parts by mass of triethylamine was added to obtain a polyurethane prepolymer solution. Next, 450 g of water was added to a reaction vessel equipped with a homodisperser capable of high-speed stirring, and the temperature was adjusted to 25°C. The mixture was stirred for 2000 min. -1 While stirring and mixing at 50°C, the polyurethane prepolymer solution was added and dispersed in water. Then, acetone and a portion of the water were removed under reduced pressure to prepare a water-soluble polyurethane resin (D-1) with a solids concentration of 35% by mass. The glass transition temperature of the resulting polyurethane resin was -30°C.

[0149] (Production of oxazoline-based crosslinking agents) A flask equipped with a thermometer, nitrogen gas inlet tube, reflux condenser, dropping funnel, and stirrer was charged with a mixture of 58 parts by mass of ion-exchanged water and 58 parts by mass of isopropanol as an aqueous medium, and 4 parts by mass of a polymerization initiator (2,2'-azobis(2-amidinopropane) dihydrochloride). The dropping funnel was charged with a mixture of 16 parts by mass of 2-isopropenyl-2-oxazoline as a polymerizable unsaturated monomer having an oxazoline group, 32 parts by mass of methoxypolyethylene glycol acrylate (average number of moles of ethylene glycol added: 9 moles, Shin-Nakamura Chemical Co., Ltd.), and 32 parts by mass of methyl methacrylate, and the mixture was added dropwise over 1 hour at 70°C under a nitrogen atmosphere. After the dropwise addition, the reaction solution was stirred for 9 hours and then cooled to obtain a water-soluble resin having an oxazoline group with a solids concentration of 40% by mass.

[0150] (Preparation of coating solution for easy adhesion layer) The following coating materials were mixed to prepare a coating solution for an easy-adhesion layer. Water 55.62% by mass Isopropanol 30.00% by mass Polyurethane resin (D-1) 11.29% by mass Oxazoline crosslinking agent (E-1) 2.26% by mass Particles 0.71% by mass (Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass) Particles 0.07% by mass (Silica sol with an average particle size of 450 nm, solid content of 40% by mass) Surfactant 0.05% by mass (Silicone-based, solid content 100% by mass) (Solid content concentration 10% by mass)

[0151] [Preparation of uniaxially stretched PET film (Film A)] PET resin pellets with an intrinsic viscosity of 0.62 were fed into an extruder as a raw material for the film, extruded from a die into a sheet, and then wound around a casting drum at a surface temperature of 30°C using an electrostatic casting method, followed by cooling and solidification to produce an unstretched film. Next, a coating solution for an easy-adhesion layer was applied to both sides of this unstretched PET film by a reverse roll method, with the coating amount after drying being 0.12 g / m. 2 After applying the coating so that the coating was uniform, the coating was introduced into a dryer and dried at 80°C for 20 seconds.

[0152] The unstretched film with this coating layer formed was introduced into a tenter stretching machine, and while the edges of the film were held with clips, it was introduced into a hot air zone at 135°C and stretched 3.5 times in the width direction. Next, while maintaining the stretched width in the width direction, it was treated at 225°C for 30 seconds, and then both edges of the cooled film were cut with a shear blade to obtain Film A with a width of 1000 mm and a thickness of 50 μm.

[0153] [Preparation of biaxially stretched PET film (Film B)] An unstretched film obtained in the same manner as for Film A, except for changing the thickness, was heated to 105°C using a group of heated rolls and an infrared heater, and then stretched 3.2 times in the running direction using a group of rolls with different peripheral speeds.After that, an easy-adhesion layer was applied in the same manner as for Film A, and then stretched in the width direction to obtain Film B with a width of 1000 mm and a thickness of 50 μm.

[0154] [Preparation of uniaxially oriented polypropylene film (Film C)] Polypropylene resin pellets with MFR=7 were fed into an extruder and extruded from the die in the form of a sheet, which was then wrapped around a casting drum with a surface temperature of 60°C and cooled to solidify. The film surface was then corona-treated to obtain Film C with a width of 1000 mm and a thickness of 38 μm. The draft ratio during casting was 4.8 times.

[0155] [Preparation of biaxially oriented polypropylene film (Film D)] Polypropylene resin pellets with an MFR of 2.5 were fed into an extruder, extruded through a die into a sheet, and then wrapped around a casting drum at a surface temperature of 20°C for cooling and solidification. The resulting unstretched film was heated to 120°C using a group of rolls with different peripheral speeds and stretched 4.5 times in the running direction, then introduced into a tenter stretching machine. While holding the film's edges with clips, the film was introduced into a hot air zone at 155°C and stretched 8.0 times in the width direction. Next, while maintaining the stretched width in the width direction, the film was treated at 160°C for 30 seconds. Both ends of the cooled film were then cut with a shear blade, and one side was subjected to corona treatment to obtain Film D, 1000 mm wide and 38 μm thick.

[0156] [Coating of adhesive layer] An adhesive solution having the following composition was applied to one side of films A to D so that the thickness after drying was 5 μm to form an adhesive layer, thereby producing surface protection films A to D. The adhesive layer was provided on the adhesive layer surface of films A and B, and on the corona-treated surface of films C and D. (Adhesive solution composition) 100 parts by weight of acrylic adhesive resin (SK Dyne 1499M manufactured by Soken Chemical & Engineering Co., Ltd.) Isocyanate curing agent (Soken Chemical & Engineering Co., Ltd. D-90) 2.0 parts by mass

[0157] Example 1 [Preparation of Laminate for Transferring λ / 4 Retardation Layer] (Preparation of release film with orientation control layer formed) An alignment control layer coating composition with the following composition was applied to a triacetyl cellulose (TAC) film with an in-plane retardation of 12 nm, a thickness of 40 μm, and a width of 1000 mm 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 resulting film was then treated with a rubbing roll wrapped with a nylon napped cloth to obtain a substrate film laminated with an alignment control layer. Rubbing was performed at an angle of 45 degrees to the film formation direction (longitudinal direction) of the TAC film. Fully saponified polyvinyl alcohol (weight average molecular weight 800) 2 parts by mass Ion-exchanged water 100 parts by mass Surfactant 0.5 parts by mass

[0158] (Formation of Aligned Liquid Crystal Compound Layer) Subsequently, a solution for forming a retardation layer (aligned liquid crystal compound layer) having the following composition was applied to the rubbed surface by bar coating, dried at 110°C for 3 minutes, and cured by irradiating with ultraviolet light to form a λ / 4 retardation layer on the TAC film. Rod-shaped liquid crystal compound (BASF LC242) 92 parts by mass Trimethylolpropane triacrylate 5 parts by mass Irgacure 379 3 parts by weight Surfactant 0.1 parts by mass Methyl ethyl ketone 250 parts by mass

[0159] (Laminating surface protection film) The surface protective film A was attached to the λ / 4 retardation layer surface of the obtained TAC film laminated with the λ / 4 retardation layer, and the film was taken up into a roll with a length of 200 m. The film formation direction (longitudinal direction) of the TAC film laminated with the λ / 4 retardation layer and the film formation direction (longitudinal direction) of the surface protective film were the same.

[0160] Comparative Example 1 A transfer film laminate was obtained in the same manner as in Example 1, except that the surface protective film was changed to B.

[0161] Example 2 A transfer film laminate was obtained in the same manner as in Example 1, except that the surface protective film was changed to C.

[0162] Comparative Example 2 A transfer film laminate was obtained in the same manner as in Example 1, except that the surface protective film was changed to D.

[0163] The evaluation results of the obtained transfer film laminate (laminate of surface protective film / λ / 4 retardation layer / TAC film) are shown in Table 1. These evaluations were carried out on a sample that was unwound from a roll and cut to a length of 700 mm.

[0164] [Table 1]

[0165] The experiment described in the following Reference Example was conducted to determine the angle between the main alignment direction of the surface protection film and the longitudinal direction or width direction of the transfer film laminate required to achieve a satisfactory result in the evaluation of light leakage (6) above. This will be explained with reference to Figure 15. Figure 15 shows a plan view of a surface protection film attached to a film having an aligned liquid crystal compound layer formed on a release film, with the longitudinal directions of the film and the film attached such that they form an angle θ. Because it is difficult to manufacture a surface protection film with a main alignment direction at various desired angles, samples were prepared in which the longitudinal direction of the surface protection film was attached to the film having the aligned liquid crystal compound layer at an angle θ with respect to the longitudinal direction of the film having the aligned liquid crystal compound layer, thereby forming an angle θ between the main alignment direction and the longitudinal direction of the film having the aligned liquid crystal compound layer.

[0166] Reference examples 1~4 The TAC film laminated with the λ / 4 retardation layer obtained in Example 1 was cut to a length of 700 mm, and surface protection film A cut to a length of 700 mm was attached to the surface of this λ / 4 retardation layer. When attaching, the angles θ between the longitudinal direction of the TAC film and the longitudinal direction of the surface protection film were set to the angles shown in Table 2. The evaluation results of light leakage of the transfer film laminates obtained in Reference Examples 1 to 4 are shown in Table 2.

[0167] [Table 2]

[0168] In Reference Example 4, in which the angle between the longitudinal direction of the TAC film and the longitudinal direction of the surface protection film was 15 degrees, the light leakage evaluation was found to be poor. [Explanation of symbols]

[0169] 1: Transfer film laminate 2: Release film 20: Release base film 20a: Release layer 3: Alignment liquid crystal compound layer 31: Retardation layer 32: Polarizing layer 4: Surface protection film 40: Surface protection base film 40a: adhesive layer 401: First location 402: Second location 403: Third location 404: Location 4 405: Location 5 5:Light source 6: Linear polarizer 61: First linear polarizer 62: Second linear polarizer 7: Retardation plate 8:Reflector MD: Longitudinal direction (film-forming direction) TD: Width direction

Claims

1. A transfer film laminate for transferring an oriented liquid crystal compound layer to an object, the transfer film laminate comprising a release film, an oriented liquid crystal compound layer, and a surface protective film laminated in this order, the transfer film laminate satisfying the following (A) to (D): (A) The maximum value of the angle between the main orientation direction of the surface protection film and the longitudinal direction of the transfer film laminate, measured at the following five measurement points in the width direction of the surface protection film, is 14 degrees or less, or the maximum value of the angle between the main orientation direction of the surface protection film and the width direction perpendicular to the longitudinal direction of the transfer film laminate, measured at the following five measurement points in the width direction of the surface protection film, is 14 degrees or less. <Measurement points> The five measurement points are: a first point 5 cm inward from one end of the surface protection film in the width direction of the surface protection film; a second point 5 cm inward from the other end of the surface protection film; a third point which is the midpoint between the first point and the second point; a fourth point which is the midpoint between the first point and the third point; and a fifth point which is the midpoint between the second point and the third point. (B) The release film has an in-plane retardation of 0 to 50 nm. (C) The in-plane retardation of the surface protective film is 100 nm or more. (D) The surface protection film has a surface protection substrate film and an adhesive layer, and the adhesive layer is provided directly on the surface of the surface protection substrate film facing the aligned liquid crystal compound layer, or the adhesive layer is provided directly via an easy-adhesion layer.

2. A transfer film laminate as described in Claim 1, wherein the adhesive layer of the surface protection film is directly laminated to the oriented liquid crystal compound layer.

3. A transfer film laminate as described in claim 1 or 2, wherein the oriented liquid crystal compound layer is an absorptive polarizing layer.

4. A transfer film laminate as described in claim 1 or 2, wherein the oriented liquid crystal compound layer includes a λ / 4 phase difference layer, and the slow axis of the λ / 4 phase difference layer is arranged at an angle of 10 to 80 degrees relative to the longitudinal direction of the transfer film laminate.

5. A transfer film laminate described in any one of claims 1 to 4, wherein the oriented liquid crystal compound layer is provided by coating on the release film or on an orientation control layer provided on the release film.

6. 6. The transfer film laminate according to claim 1, wherein the peel strength between the oriented liquid crystal compound layer and the surface protective film is 0.005 to 2 N / 25 mm.

7. A method for producing the transfer film laminate according to any one of claims 1 to 6, laminating the release film, the aligned liquid crystal compound layer, and the surface protection film to form a transfer film laminate; A manufacturing method characterized by having a step of inspecting the alignment state of the oriented liquid crystal compound layer using at least one of the following specific optical systems (1) to (4) after the step of forming the transfer film laminate. <Specific optical system> (1) (a) A light source is arranged on the side of the transfer film laminate facing the surface protective film, a first linear polarizer is arranged between the transfer film laminate and the light source, a second linear polarizer is arranged on the side of the transfer film laminate facing the release film, and a retardation plate is arranged between the transfer film laminate and the second linear polarizer, or (b) A light source is arranged on the side of the transfer film laminate facing the release film, a first linear polarizing plate is arranged between the transfer film laminate and the light source, a second linear polarizing plate is arranged on the side of the transfer film laminate facing the surface protection film, and a retardation plate is arranged between the transfer film laminate and the first linear polarizing plate. (2) A light source is arranged on the side of the transfer film laminate facing the release film or the side facing the surface protective film, and a linear polarizing plate is arranged on the side of the transfer film laminate where the light source is not arranged or between the transfer film laminate and the light source. (3) A light source is arranged on the side of the transfer film laminate facing the surface protection film, a reflector is arranged on the side of the transfer film laminate where the light source is not arranged, and a linear polarizing plate is arranged between the transfer film laminate and the light source. (4) A light source is arranged on the side of the transfer film laminate facing the release film or the side facing the surface protective film, a reflector is arranged on the side of the transfer film laminate where the light source is not arranged, and a linear polarizer is arranged between the transfer film laminate and the light source or between the transfer film laminate and the reflector.

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