TW202019689A - Optical film - Google Patents

Abstract

An objective of the present invention is to provide an optical film capable of satisfactorily peeling a surface protective film even when it has a notch.

As a solution, the optical film of the present invention includes a polarizing plate and a surface protective film that is detachably bonded to one surface of the polarizing plate, the surface protective film has a base material layer and an adhesive layer. The optical film has a square shape or a rounded square shape having a notch on at least one side in a plan view. The optical film has a glue notch portion formed so that at least an end portion of the surface of the adhesive layer on the polarizing plate side is located 15 μm or more inside from the end portion of the base material layer, the glue notch portion is formed on at least a portion of one side having a notch.

Description

Optical film

The present invention relates to optical films.

When manufacturing the polarizing plate or when the polarizing plate is circulating on the market, a surface protective film that can be peeled off may be attached to the polarizing plate to protect the surface. Such a surface protective film is usually peeled off and removed when the polarizing plate is assembled in a device such as a display device or after the assembly is completed.

[Prior Technical Literature]

[Patent Literature]

[Patent Literature 1] Japanese Patent Laid-Open No. 2004-170907

In mobile terminals such as smartphones and tablet computers that use polarizers, the display (display section) may not be square, but may have a cutout formed on a part of the side forming the square. In the display with such a cutout, it will fit with the shape of the display Polarizing plate with cutout. Since the polarizing plate is circulated by laminating a surface protective film on one surface and an optical film of a peeling film covering the adhesive layer for polarizing plate on the other surface, the surface protective film also has a cutout.

When assembling the polarizing plate to the display, first, the peeling film is peeled off from the optical film and the optical film is bonded to the display element via the exposed adhesive layer. Next, the polarizing plate is assembled to the display by peeling the surface protective film from the optical film.

The optical film having a cutout has a problem that it is not easy to peel off the surface protective film. Specifically, the peeling tape is attached to the surface protective film of the optical film (for example, refer to the symbol “39” shown in FIG. 2), and sometimes the surface is pulled up by holding the peeling tape The protective film peeled off. At this time, if there is a region where the direction in which the peeling tape is pulled up does not match the direction in which the surface protective film is pulled up, the peeling tape may be removed from the surface protective film, and the surface protective film cannot be peeled from the optical film.

An object of the present invention is to provide an optical film capable of peeling a surface protective film well even if it has a cutout.

The present invention provides the following optical films.

[1] An optical film comprising a polarizing plate and a surface protective film releasably attached to one surface of the polarizing plate, wherein,

The aforementioned surface protection film has a base material layer and an adhesive layer,

In a plan view, the optical film is a square or a rounded square with a cutout on at least one side.

The optical film has a defect portion formed by making at least the surface end of the adhesive layer on the polarizing plate side 15 μm or more inward from the end of the base material layer,

The deficiencies are formed on at least a part of one side of the cutout.

[2] The optical film according to [1], wherein the optical film of the cutout portion has a concave shape recessed toward a side facing the side having the cutout portion when the optical film is viewed in plan.

[3] The optical film according to [1] or [2], wherein the square or rounded square is a rectangle or a rounded rectangle, and one side having the cutout is at least one of short sides.

[4] The optical film according to [2] or [3], wherein the deficiencies are formed in a range of 15% or more of the length of one side of the notch.

[5] The optical film according to any one of [2] to [4], wherein the deficiencies are continuously formed in a range of 15% or more of the length of one side of the cutout.

[6] The optical film according to any one of the items [1] to [5], wherein the optical film further has a hole portion, and the deficiencies are further formed in at least a part of the peripheral portion of the hole portion.

[7] The optical film according to [6], wherein the deficiencies are formed in at least one side having the notch in the peripheral portion of the hole.

[8] An optical film comprising a polarizing plate and a surface protective film releasably attached to one surface of the polarizing plate, wherein,

The aforementioned surface protection film has a base material layer and an adhesive layer,

The aforementioned optical film system has: a hole, and

A defect portion formed by at least a surface end portion of the adhesive layer on the polarizing plate side 15 μm or more inward from the end portion of the base material layer,

The deficiencies are formed in at least a part of the surrounding portion of the hole.

[9] The optical film according to any one of [6] to [8], wherein the deficiencies are formed all around the hole.

[10] The optical film according to any one of [1] to [9], wherein the deficiencies are such that the surface end of the adhesive layer on the polarizing plate side is closer to the surface of the adhesive layer The surface end portion on the base material layer side is formed closer to the inner side.

[11] The optical film according to any one of [1] to [10], wherein the peeling force between the polarizing plate and the surface protective film is 0.10 N/25 mm or less.

[12] The optical film according to any one of [1] to [11], wherein the optical film has a polarizing plate adhesive layer on the polarizing plate side.

According to the optical film of the present invention, the surface protective film can be peeled off satisfactorily even if there is a cutout.

10, 50, 60, 70, 80, 90 ‧‧‧ optical film

10a to 10d, 50a, 60a, 70a, 70c

11, 51, 61a, 61b, 71, 73, 81

12, 17‧‧‧ lack of department

16‧‧‧ Hole

20, 21‧‧‧ Polarizer

30、33‧‧‧Surface protective film

31, 34‧‧‧ substrate layer

32、35‧‧‧Adhesive layer

39‧‧‧ Stripping tape

40‧‧‧Cutting device

41‧‧‧Up pressure tool

42‧‧‧Lower holding tool

43‧‧‧Pushing appliances

44‧‧‧rotating table

45、46‧‧‧Cutting rotating body

h1‧‧‧Width of cut

h2‧‧‧Depth of cut

L1, L2‧‧‧Distance

Pab, Pbc, Pcd, Pda

Fig. 1 (a) is a schematic plan view schematically showing an example of the optical film of the present invention, Fig. 1 (b) is a MM' cross-sectional view in (a), and Fig. 1 (c) is in (a) NN' section view.

FIG. 2 is a schematic plan view schematically showing an example of the step of peeling the surface protective film from the optical film of the present invention.

FIG. 3 is a schematic perspective view schematically showing an example of a cutting device used for manufacturing the optical film of the present invention.

4(a) to (d) are schematic plan views schematically showing other examples of the optical film of the present invention.

Fig. 5(a) is a schematic plan view schematically showing still another example of the optical film of the present invention, and Fig. 5(b) is a Q-Q' cross-sectional view in (a).

Fig. 6 is a schematic plan view schematically showing still another example of the optical film of the present invention.

FIG. 7 is a diagram showing an image obtained by observing the surface of the surface protection film on the side of the adhesive layer using an optical microscope.

Fig. 8 is a schematic plan view of optical films obtained in Examples and Comparative Examples.

(Form for implementing the invention)

Hereinafter, preferred embodiments of the optical film of the present invention will be described with reference to the drawings. In addition, the scope of the present invention is not limited by the embodiments described herein, and does not impair the gist of the present invention. Various changes can be made within the scope.

[First Embodiment]

Figures 1 (a) to (c) are schematic diagrams schematically showing an example of an optical film. Figure 1 (a) is a plan view, and Figure 1 (b) is M- in Figure 1 (a). M'cross-sectional view, Fig. 1(c) is a NN' cross-sectional view in Fig. 1(a). The optical film 10 of this embodiment is as shown in (a) to (c) of FIG. 1,

Including the polarizing plate 20 and the surface protective film 30 that can be peelably attached to one surface of the polarizing plate 20,

The surface protection film 30 has a base material layer 31 and an adhesive layer 32,

In a plan view, the optical film 10 has a rounded square shape with a cutout 11 on one side,

The optical film 10 has a defect portion 12 formed by making the surface end portion of the adhesive layer 32 at least on the polarizing plate 20 side 15 mm or more inward from the end portion of the base material layer,

The missing portion 12 is formed on at least a part of the side 10a having the notch 11.

The optical film 10 may have an adhesive layer for polarizing plates on the surface on the polarizing plate 20 side. In this case, the optical film sequentially has a surface protective film, a polarizing plate, and an adhesive layer for polarizing plates. Furthermore, the optical film may further have a peeling film covering the adhesive layer for polarizing plates. In this case, the optical film sequentially has a surface protective film, a polarizing plate, an adhesive layer for polarizing plates, and a peeling film.

In this embodiment, as shown in FIG. 1(a), a rounded rectangular optical film 10 having four rounded portions in a plan view will be described as an example, but the optical film system is not limited to this. The optical film may have a square shape, or one or more of the four corners of the square shape having rounded corners, and corner portions and rounded corner portions may be blended and mixed. In addition, in this specification, a rounded square refers to a shape in which at least one of the four corners of the square is rounded, and a square refers to a shape having four corners. In addition, in this specification, a square means a rectangle or a square. also, The boundary between two consecutive sides across the rounded portion of the rounded square optical film is a position that bisects the outline length of the rounded portion. The outline length of the rounded portion is the length between the ends of the straight line portions of the two straight sides that are continuous across the rounded portion on the side of the rounded portion.

The optical film 10 shown in FIG. 1(a) has rounded rectangles with sides 10a, 10c belonging to two short sides, and sides 10b, 10d belonging to two long sides, and has a cutout 11 at side 10a. In the optical film 10, the boundary between the side 10a and the side 10b and the side 10d is the position where the outline length of the rounded portion is bisected Pab, Pda, and the border between the side 10c and the side 10b and the side 10d is the outline of the rounded portion The positions Pbc and Pcd whose length is halved (both are the positions shown with black dots in Figure 1(a)). Therefore, the length of each side of the optical film 10 is the length of the outline of the optical film 10 between the above four positions, the length of the side 10a is the length from the position Pab to the position Pda, and the length of the side 10b is the position from The length from Pab to the position Pbc, the length of the side 10c is the length from the position Pbc to the position Pcd, and the length of the side 10d is the length from the position Pcd to the position Pda.

As described above, the optical film 10 has a notch 11 on a part of the side 10a that belongs to the short side. As shown in FIG. 1(a), the notch portion 11 has a concave shape that is recessed toward the side 10c opposite to the side 10a. The cutout portion 11 is a portion of a region where the optical film 10 is not bonded to the polarizing plate 20. For example, when the polarizing plate 20 is used in a smartphone, in order not to install the receiver, speaker, camera lens, LED light, distance sensor, illuminance sensor, fingerprint identification sensor, operation button, etc. in the smartphone The polarizing plate 20 is bonded to at least one of the areas, and the optical film 10 is provided with a cutout 11. The depth of the cutout 11 can be 20 mm or less.

The optical film 10 is formed by laminating the polarizing plate 20 and the surface protective film 30 as shown in (b) and (c) of FIG. 1. The surface protective film 30 has a base material layer 31 and an adhesive layer 32 and is bonded to the polarizing plate 20 via the adhesive layer 32. The polarizing plate 20 is used in a liquid crystal display, an organic EL display, or the like. The surface protective film 30 is used to protect the surface of the polarizing plate 20 when the optical film 10 is manufactured or distributed. Therefore, the surface protective film 30 is peeled off and removed from the optical film 10 when the polarizing plate 20 is assembled in a device such as a display device or after the assembly is completed.

The optical film 10 has a defect portion 12 formed by making the surface end of the adhesive layer 32 on the polarizing plate 20 side a length L1 inward from the end of the base material layer 31. As shown in FIG. 1(c), the end of the adhesive layer 32 of the missing portion 12 has a surface end of the adhesive layer 32 on the polarizing plate 20 side that is closer to the base material layer 31 than the adhesive layer 32 The end of the side surface is closer to the tapered shape of the inside. In FIG. 1(c), it is shown that the end of the adhesive layer 32 forms a tapered defect portion 12, but as long as the surface end of the adhesive layer 32 on the polarizing plate 20 side is removed from the end of the base material layer 31 It is formed from the length of the inner distance L1, but it is not limited to this. For example, the end of the adhesive layer 32 may be formed in a stepped or curved shape. The surface end of the adhesive layer 32 on the base material layer 31 side or the surface end on the polarizing plate 20 side may also be The length from the end to the inside distance L1.

The distance L1 in the missing portion 12 may be 15 μm or more, preferably 20 μm or more, more preferably 30 μm or more, more preferably 40 μm or more, more preferably 50 μm or more, usually 500 μm or less, or 100 μm or less . When the distance L1 is 15 μm or more, when the surface protective film 30 is peeled off from the optical film 10, even if the surface protective film 30 is peeled off from the side 10 a side, it is possible to suppress the peeling failure in which the surface protective film 30 cannot be peeled off. When the distance L1 is too large, when the end of the surface protective film 30 is rolled up from the surface of the polarizing plate 20 to manufacture the optical film 10 or When the market is in circulation, it is easy to produce bad conditions.

The distance L1 can be obtained by peeling the surface protective film 30 from the optical film 10 and observing the surface of the adhesive layer 32 side using an optical microscope, and from the end of the base material layer 31 to the polarizing plate 20 side of the adhesive layer 32 Among the distances up to the end of the surface, the shortest distance is measured and obtained.

This measurement is performed at all end positions on the side of the base material layer having the edge of the notch portion 11, and if there is 15 μm or more among the measured distance L1, it is judged that there is a deficiencies with a distance L1 of 15 μm or more 12.

FIG. 7 is a diagram showing an image obtained by peeling the surface protective film 30 from the optical film 10 and observing the surface on the adhesive layer 32 side using an optical microscope. In FIG. 7, the dark-black strip-shaped portion extending obliquely from the upper left to the lower right is the missing portion 12, and the width of the strip-shaped portion is measured in the above-mentioned order to determine the distance L1. In addition, in FIG. 7, the adhesive layer 32 of the surface protection film 30 is tilted lower to the left than the dark black band, and the upper side is tilted to the right than the dark black band. The glass used for microscope observation.

The missing portion 12 shown in FIG. 1(c) is formed on at least a part of the side 10a having the cutout portion 11 shown in FIG. 1(a). Thereby, when the polarizing plate 20 is assembled in a device such as a display device or after the assembly is completed, when the surface protective film 30 is peeled off from the optical film 10, it is possible to suppress peeling defects such as the inability to peel the surface protective film 30.

FIG. 2 is a schematic plan view schematically showing an example of the step of removing the surface protective film 30 from the optical film 10. The reason why the above-mentioned peeling defect can be suppressed in the optical film 10 is presumed as follows. The surface protective film 30 is peeled off from the optical film 10, as shown in FIG. 2, for example, the peeling tape 39 is attached to the back of the optical film 10 in a notch 11 so as to span the side 10a The surface on the surface protective film 30 side, and the peeling tape 39 is pulled in the direction from the side 10a toward the side 10c (arrow direction in FIG. 2) to peel the surface protective film 30. When the cutout 11 is formed like the optical film 10 shown in FIG. 2, it is necessary to pull the peeling tape 39 so that the part recessed from the cutout 11 toward the side 10c side faces both ends of the side 10a (position Pab , Pda side) and the surface protection film 30 is pulled up. At this time, the direction in which the surface protective film 30 is pulled up does not match the direction in which the peeling tape 39 is pulled up (arrow direction in FIG. 2). Therefore, even if the peeling tape 39 is pulled up, it is not easy to pull up the surface protective film 30 in the direction from the attaching position of the peeling tape 39 toward both end sides of the side 10a (positions Pab, Pda side), and The peeling tape 39 peels from the surface protection film 30, and the peeling failure of the surface protection film 30 from the optical film 10 cannot be peeled off.

In this embodiment, the missing portion 12 is provided on at least a part of the side 10 a of the optical film 10. Thereby, the peeling force of the polarizing plate 20 and the surface protective film 30 can be reduced on the side 10a side of the optical film 10, especially at the initial stage of pulling up, so as described above, even if there is a direction and pulling up of the peeling tape 39 The presence of a region in which the direction of the surface protection film 30 does not match can also suppress the occurrence of peeling defects in which the peeling tape 39 peels from the surface protection film 30 and the surface protection film 30 cannot be peeled from the polarizing plate 20. Especially in recent years, the peeling of the surface protective film is not carried out by human power, but by the advancement of automation by machinery (peeling device). In addition, in the peeling of the surface protective film 30 by the peeling device, from the viewpoint of production efficiency, etc., the peeling speed is also increased (for example, 50 to 150 sec/mm). According to the present embodiment, by providing the missing portion 12 on the side 10a having the cutout portion of the optical film 10, even if the peeling tape 39 attached to the surface protective film 30 of the optical film 10 is fixed to the peeling device, the When the surface protective film 30 peels at a high speed, the peeling failure of the surface protective film 30 can also be suppressed.

In the optical film 10 shown in FIG. 2, the case where the peeling tape 39 is attached to the cut portion 11 is described as an example, but even if the peeling tape 39 is attached to the side 10a, the cut portion 11 is not formed When the surface protective film 30 is peeled off in a region where the surface protective film 30 is peeled, defective peeling of the surface protective film 30 can be suppressed. When attaching the peeling tape 39 to the area where the cutout portion 11 is not formed on the side 10a, the direction in which the surface protective film 30 is pulled up on the portion of the cutout portion 11 that is recessed toward the side 10c side is the same as pulling the peeling tape 39 The starting direction (arrow direction in Figure 2) is inconsistent. Therefore, it is considered that by providing the missing portion 12 on at least a part of the side 10a of the optical film 10, the peeling force of the polarizing plate 20 and the surface protective film 30 can be reduced on the side 10a of the optical film 10 to suppress the surface protective film 30 Poor peeling.

The missing portion 12 only needs to be provided on at least a part of the side 10 a where the cut portion 11 is formed. The missing portion 12 is preferably provided in at least a part of the range where the notch portion 11 is formed in the side 10a, and is preferably provided in a position where the peeling tape 39 is attached and its periphery. In addition, when the peeling tape 39 is attached to the position shown in FIG. 2, the missing portion 12 may be provided at the curved portion of the side 10a, but it is preferably formed at the straight portion. Therefore, although the reason is not clear, when the surface protective film 30 is pulled up using the peeling tape 39, the peeling force between the polarizing plate 20 and the surface protective film 30 is easily reduced. The missing portion 12 may be formed on all of the sides 10a to 10d of the optical film 10, that is, around the entire outline of the optical film 10.

The missing portion 12 is preferably formed in the range of 15% or more of the length from the side 10a (the length along the outline of the optical film 10 from the position Pab to the position Pda), and is formed in the range of 20% or more Preferably, it is more preferably formed in a range of 30% or more, or in a range of 40% or more, or in a range of 50% or more. In addition, the range where the missing portion 12 is formed may be the full length (100%) of the length of the side 10a, but from the polarizing plate 20 and the surface protective film 30 From the viewpoint of adhesion, it is preferably 90% or less, and preferably 80% or less. The missing portion 12 may be formed intermittently so that the total length of the area where the pasting portion 12 is formed within the length of the side 10a within the range of the above ratio, or may be formed continuously within the above range.

The range in which the missing portion 12 is formed can be observed using an optical microscope in the same manner as the calculation method of the distance L1 described above, and is obtained by calculating the outline length of the optical film 10 at a portion where the distance L1 is 15 μm or more.

The peeling force between the polarizing plate 20 of the optical film 10 and the surface protective film 30 is preferably 0.10N/25mm or less, preferably 0.09N/25mm or less, more preferably 0.08N/25mm or less, or It is 0.07N/25mm or less. The peeling force between the polarizing plate 20 of the optical film 10 and the surface protective film 30 is the peeling force in the region where the deficiencies 12 are not formed, and can be measured by, for example, the method described in Examples described later. The peeling force can be determined by the type of the adhesive used for the adhesive layer 32 of the surface protective film 30, the thickness of the base material layer 31 of the surface protective film 30, and the surface treatment on the surface protective film 30 side of the polarizing plate 20 ( Hydrophilization treatment, etc.).

The optical film blank film laminated with the long polarizing plate 20 and the long surface protective film 30 is cut into a blade shape to obtain a blade-shaped optical film, and the end surface of the blade-shaped optical film is cut , The optical film 10 can be obtained. Cutting the blade-shaped optical film from the optical film blank film can be performed by punching or cutting. In addition, the deficiencies 12 of the optical film 10 can be formed when the blade-shaped optical film is cut.

As shown in FIG. 3, the cutting processing of the blade-shaped optical film is performed using the cutting processing device 40 on the laminate W in which a plurality of blade-shaped optical films are stacked. FIG. 3 schematically shows an example of a cutting device 40 used in the manufacture of the optical film 10 Slightly oblique view. As shown in FIG. 3, the cutting device 40 includes a pressing tool 41 and a lower pressing tool 42 for holding and fixing the laminate W in the z direction (stacking direction of blade-shaped optical films). The lower pressing tool 42 is supported by the rotating table 44, and the pressing tool 43 is attached to the upper pressing tool 41, and the pressing tool 43 can rotate synchronously when the rotating table 44 rotates. In addition, the cutting machine 40 is provided with two cutting rotating bodies 45 and 46 for cutting the end face of the laminate W. The cutting rotors 45 and 46 are, for example, Router end mills, and have a cylindrical rotating body and a plurality of cutting edges arranged along the rotation direction on the side surface of the cylindrical rotating body. The cutting rotating bodies 45 and 46 are provided in the y direction so as to be separable from the laminated body W, and can be moved according to the size of the laminated body W or the cutting amount of the laminated body W.

The laminate W mounted on the cutting device 40 is stacked in such a manner that the four sides of the blade-shaped optical film are aligned in the stacking direction, and the surface protection film 30 side can be stacked upward, and the polarizing plate can also be Stack with 20 sides (or peeling film side) facing up. When the cutting device 40 forms the linear portions of the sides 10b and 10d of the optical film 10, for example, the positions of the cutting rotating bodies 45 and 46 in the x-direction and z-direction are fixed with the rotation axis (cylindrical) (Axis) is rotated about the center, and the laminated body W is moved in the x direction between the cutting rotating bodies 45, 46, whereby the end surface of the laminated body W can be cut. In the cutting device 40, when forming the linear portions of the sides 10a and 10c of the optical film 10, it is only necessary to perform the same process as when forming the sides 10b and 10d, and when forming the cutout portion 11, it is only necessary to move the laminate in the x direction. While one of the cutting rotating bodies 45 and 46 is moved in the y direction according to the shape of the cutout portion 11, the end surface of the laminate W may be cut. In addition, the rounded portion of the optical film 10 can be formed by cutting the rotating body in a rounded shape while rotating the rotary table 44 by 90° while the rotating cutting rotating bodies 45 and 46 are in contact with the laminate W 45, 46 move in the y direction, thereby cutting the corner of the laminate W Formed.

As described above, when the cutting device 40 is used to cut the end surface of the laminate W, for example, by adjusting the rotation speed of the cutting rotating bodies 45 and 46, the amount of movement of the cutting rotating bodies 45 and 46 in the y direction, The moving speed (transport speed) of the laminate W changes the state of the end surface of the obtained optical film 10. This makes it possible to adjust the degree (distance L1) of the missing portion 12 (the first figure (c)) formed in the optical film 10 and the shape of the missing portion 12. The distance L1 of the missing portion 12 can be increased by, for example, reducing the rotation speed of the cutting rotating bodies 45 and 46, reducing the moving speed of the laminate W, and the like.

The optical film system of this embodiment can be modified as shown in the modification examples below, and can also be implemented by combining the structures and steps of the embodiment and its modification examples.

(Modification 1 of the first embodiment)

In the above embodiment, the optical film 10 having one concave cutout portion 11 in a part of the side 10a is described, but the entire side 10a may be formed with a cutout portion, or may have more than two concaves in the side 10a状切部。 Shaped cut.

(Modification 2 of the first embodiment)

In the optical film 10, the case where the concave cutout portion 11 is provided will be described as an example, but the shape of the cutout portion is not limited to this. For example, instead of the notch portion 11 shown in FIG. 1 (a), the notch portion shown in FIGS. 4 (a) to (d) may be provided. Figs. 4 (a) to (d) are schematic plan views schematically showing other examples of the optical film of this embodiment.

The optical film 50 shown in FIG. 4(a) has a stepped notch 51 at the side 50a instead of the concave notch 11 shown in FIG. 1(a). The optical film 60 shown in FIG. 4(b) has two stepped notches 61a and 61b on the side 60a instead of shown in FIG. 1(a) 之 concave cutout 11. The stepped cutout portions 51, 61a, and 61b provided in the optical films 50 and 60 are preferably provided on the rounded rectangle or the short side of the rectangle.

The optical film 70 shown in FIG. 4(c) has concave cutouts 71 and 73 on each side 70a and side 70c. The cutouts 71 and 73 of the optical film 70 may have the same shape or different shapes, for example, one may be a concave cutout and the other may be a stepped cutout.

The optical film 80 shown in FIG. 4(d) has a U-shaped cutout 81 instead of the cutout 11 shown in FIG. 1(a). The corner portion (the bottom portion of the U-shape) of the U-shaped cut-out portion 81 may be a curve as shown in FIG. 4(d) or a right angle. In addition, in the optical film, the shape of the concave cutout is not particularly limited, and may be a shape other than the shapes shown in FIGS. 1(a) and 4(d), for example, may be V-shaped.

The optical films shown in FIGS. 1(a) and 4(a) to (d) illustrate the case where the notch is provided on the short side of the rounded rectangle, but it can also be provided on the long side Notch. Moreover, one notch may be provided on each side, or two or more may be provided. When two or more are provided, the shape of the notch may be the same as or different from each other.

[Second Embodiment]

Fig. 5 (a) and (b) are schematic diagrams schematically showing other examples of optical films, Fig. 5 (a) is a plan view, and Fig. 5 (b) is Q- in Fig. 5 (a) Q'section view. In the following, the same members as those already explained in the previous embodiment are denoted by the same symbols and their descriptions are omitted.

The optical film 90 of this embodiment differs from the optical film 10 in that the optical film 10 shown in FIG. 1(a) is provided with a hole 16. The hole 16 penetrates the entire optical film 90 and is provided on both the polarizing plate 21 and the surface protective film 33 (FIG. 5(b) ). For example, when the optical film 90 is used in a smartphone, the hole 16 is an area where the camera lens is provided. The diameter of the hole 16 For example, it can be set to 2 mm or more, or 5 mm or more, and usually 20 mm or less, or 15 mm or less, preferably 10 mm or less. As shown in FIG. 5(a), the hole 16 may be circular, polygonal such as elliptical, quadrangular, hexagonal, and rounded polygonal.

As shown in FIG. 5(b), the optical film 90 is formed by laminating a polarizing plate 21 and a surface protective film 33. The surface protection film 33 has a base material layer 34 and an adhesive layer 35, and is bonded to the polarizing plate 21 via the adhesive layer 35. The polarizing plate 21 and the surface protective film 33 are different from the polarizing plate 20 and the surface protective film 30 (FIG. 1(b)) at the point where they have holes.

Like the optical film 10, the optical film 90 has a missing portion 12 on the side 10a provided with the notch portion 11, and also has a missing portion 17 around the hole portion 16 (FIG. 5(b)). The optical film 90 has a defect portion 17 formed by making the surface end of the adhesive layer 35 on the polarizing plate 21 side a length L2 inward from the end of the base material layer 33. As shown in FIG. 5(b), the end of the adhesive layer 35 in the missing portion 17 has the surface end of the polarizing plate 21 side of the adhesive layer 35 closer to the base material layer 34 side than the adhesive layer 35 The end of the surface is closer to the tapered inside. FIG. 5(b) shows that the end of the adhesive layer 35 is formed with a tapered defect portion 17, but as long as the surface end of the adhesive layer 35 on the polarizing plate 21 side is removed from the end of the base material layer 34 It is formed only at a distance of L2 from the inside, and it is not limited to this. For example, the end of the adhesive layer 35 may be formed in a stepped or curved shape, and the surface end of the adhesive layer 35 on the base material layer 34 side or the surface end on the polarizing plate 21 side may also be separated from the base material layer 34 The length of the end from the inward distance L2.

The distance L2 in the missing portion 17 is 15 μm or more, preferably 20 μm or more, more preferably 30 μm or more, more preferably 40 μm or more, more preferably 50 μm or more, usually 500 μm or less, or 100 μm or less. By setting the distance L2 to 15 μm or more, when the surface protective film 33 is peeled from the optical film 90, it is possible to suppress the surface around the hole 16 The peeling of the protective film 30 is poor. When the distance L2 is too large, the surface protection film 33 floats from the surface of the polarizing plate 21 around the hole portion 16 and is liable to cause defects during the manufacture or circulation of the optical film 90. The distance L2 can be obtained using the same method as the method for obtaining the distance L1 described in the previous embodiment.

The missing portion 17 only needs to be formed in a part of the surrounding portion of the hole portion 16, preferably 50% or more of the length around the hole portion 16, preferably 80% or more, or 90% or more For better results, it may be formed all around the hole 16 (100%). The missing portion 17 may be formed intermittently so that the total length of the regions in which the pasting portion 17 is formed among the lengths around the hole portion 16 is within the range of the above ratio, or may be formed continuously within the above range. In addition, the missing portion 17 is preferably formed on the side 10 a side having the notch 11 among the peripheral portions of the hole 16. The so-called side 10a side having the cutout 11 in the peripheral portion of the hole 16 means that the contour of the side 10a and the hole 16 face each other without interposing the hole 16 in the surface direction of the optical film 90 Part. The range of the missing portion 17 formed around the hole portion 16 can be obtained by the same method as the method for calculating the range of forming the missing portion 12 described in the previous embodiment.

As described in the previous embodiment, when the surface protective film 33 is peeled off from the optical film 90, it will be on the side 10a side of the optical film 90 in the same manner as the peeling method described in the previous embodiment based on FIG. The peeling tape 39 is attached to the surface protection film 33, and the peeling tape 39 is pulled up to peel off the surface protection film 33. In a part of the region of the optical film 90 where the hole 16 is formed, since the direction of pulling up the surface protection film 33 is not consistent with the direction of pulling up the surface protection film 33 at the attachment position of the peeling tape 39, there will be It is difficult to pull up the surface protection film 33 around the hole 16. Therefore, in this embodiment, the system will lack The paste portion 17 is provided in at least a part of the hole portion 16 of the optical film 90. By this, since the peeling force of the polarizing plate 21 and the surface protective film 33 around the hole 16 can be reduced, it is considered that the surface protective film 33 around the hole 16 can be prevented from being peeled off. As described above, by providing the missing portion 17 in the peripheral portion of the hole portion 16, especially the side 10a with the notch portion 11, the peeling of the side of the hole portion 16 that pulls up the surface protective film 33 can be reduced Therefore, it is considered that it is easier to pull up the surface protection film 33 around the hole 16.

The hole portion 16 can be formed by, for example, piercing a laminate W in which a plurality of blade-shaped optical films are stacked or a laminate W subjected to a cutting process using a rotary cutter such as a drill. The missing portion 17 formed in the hole portion 16 can be adjusted by adjusting the rotation speed of the rotary cutting tool, adjusting the cutting blade size of the rotary cutting tool, and the like. The distance L2 of the missing portion 17 can be increased by, for example, reducing the rotation speed of the rotary cutting tool, increasing the amount of protrusion of the cutting edge of the rotary cutting tool, or the like.

The optical film of this embodiment can be modified into the modified examples shown below, or can be implemented by combining the structures and steps of the above-described embodiments and modified examples.

(Modification of the second embodiment)

Fig. 6 is a schematic plan view schematically showing another example of the optical film. In the above-mentioned embodiment, the optical film 90 having the cutout 11 on the side 10a and the hole 16 is described. However, as shown in FIG. 6, the optical film 90 without the cutout 11 and having only the hole 16 may be used. membrane.

The materials and the like constituting each layer of the optical film are described in detail below.

(Polarizer)

The polarizing plate is provided with a protective layer on at least one side of the polarizer, or may have protection on both sides Layers. The thickness of the polarizing plate can generally be 5 μm or more and 200 μm or less, and may be 150 μm or less or 120 μm or less.

The polarizer is an absorption type polarizer that absorbs linear polarized light having a vibration surface parallel to its absorption axis and transmits linear polarized light having a vibration surface orthogonal to the absorption axis (parallel to the transmission axis). The polarizer may be a polarizing film formed by aligning a dichroic dye with a polyvinyl alcohol-based resin film, or a polarizing layer containing a polymerizable liquid crystal compound and a dichroic dye and aligned with a polymerizable liquid crystal compound. The thickness of the polarizer can be, for example, 1 μm or more and 20 μm or less, 10 μm or less, 8 μm or less, or 5 μm or less.

The protective layer may be an optically transparent thermoplastic resin, for example: polyolefin resin such as chain polyolefin resin (polypropylene resin, etc.), cyclic polyolefin resin (norbornene resin, etc.); such as three Cellulose resins of cellulose acetate and cellulose diacetate; such as polyester resins of polyethylene terephthalate and polybutylene terephthalate; such as polycarbonate resins; methyl methacrylate (Meth)acrylic resin based on resin; polystyrene based resin; polyvinyl chloride based resin; acrylonitrile/butadiene/styrene based resin; acrylonitrile/styrene based resin; polyvinyl acetate based resin; poly Vinylidene chloride-based resins; Polyamide-based resins; Polyacetal-based resins; Modified polyphenylene ether-based resins; Polyphenol-based resins; Polyether-based resins; Polyaromatic ester-based resins; Polyamide amides Amine resin; Polyimide resin; Coating layer or film composed of a mixture of one or more of these resins. The thickness of the protective layer is usually 1 μm or more and 100 μm or less, or 5 μm or more and 80 μm or less, 60 μm or less, or 50 μm or less.

When the protective layer is a protective film, for example, the protective film can be bonded to the polarizer through an adhesive layer. Examples of the adhesive for forming the adhesive layer include water-based adhesives, active energy ray-curable adhesives, or thermosetting adhesives, and water-based adhesives and active energy ray can be used. Hardening adhesives are preferred.

The polarizing plate may also have an optical functional layer such as an anti-glare layer, a light diffusion layer, a phase difference layer, an anti-reflection layer, or a surface treatment layer such as a hard coat layer, an antistatic layer, and an antifouling layer on the protective layer.

(Surface protection film)

The surface protection film has a base material layer and an adhesive layer. The thickness of the surface protective film is, for example, 15 μm or more and 100 μm or less, preferably 20 μm or more and 80 μm or less, and preferably 30 μm or more and 60 μm or less.

The resin constituting the base material layer may be, for example: a chain polyolefin resin such as polyethylene or polypropylene; a cyclic polyolefin resin such as norbornene resin; such as polyethylene terephthalate or poly Polyester resins of ethylene naphthalate; polycarbonate resins; thermoplastic resins such as mixtures of one or more of these resins.

The base material layer may have a single-layer structure or a multi-layer structure, and is preferably a single-layer structure from the viewpoint of ease of manufacturing and manufacturing cost. The substrate layer may be a uniaxially stretched film or a biaxially stretched film. From the viewpoint of the mechanical strength of the film, ease of manufacturing, manufacturing cost, and the like, the biaxially stretched film is preferably used.

The adhesive layer system can be composed of an adhesive composition containing, for example, (meth)acrylic, rubber, urethane, ester, polysiloxane, or polyvinyl ether resin as a main component. In particular, an adhesive composition using a (meth)acrylic resin having excellent transparency, weather resistance, heat resistance, etc. as a matrix polymer is preferred. The adhesive composition may also be active energy ray hardening type or thermosetting type.

(Adhesive layer for polarizing plate)

As the adhesive composition constituting the adhesive layer for polarizing plates, for example, the above-mentioned The adhesive composition that constitutes the adhesive layer.

[Example]

Hereinafter, Examples and Comparative Examples are disclosed to more specifically explain the present invention, but the present invention is not limited to these examples. In the examples and comparative examples, "%" and "parts" are% by mass and parts by mass unless otherwise specified.

[Measurement of distance L1 of missing part]

For the deficiencies formed on the side where the notch is provided, the distance from the end of the base material layer to the end of the surface of the adhesive layer on the polarizing plate side is measured according to the following procedure (equivalent to 1 Figure (c) shows the length of the distance L1). First, the surface protective film was peeled from the optical films obtained in Examples and Comparative Examples. Next, observe the surface of the adhesive layer exposed after the surface protective film is peeled off using an optical microscope at a magnification of 100 times, and measure the surface of the adhesive layer on the polarizer side from the end of the substrate layer in the observation field of view The shortest distance up to the end position.

[Calculation of the ratio of the area where the deficiencies are formed]

The above [measurement of the distance L1 of the missing portion] is performed at all the end portions on the base material layer side of the range where the missing portion is formed on the side having the notched portion, and the measurement is performed on the side having the notched portion The distance L1 is the total of the outline length of the optical film 10 in the area portion of 15 μm or more. The ratio of the total length of the outline to the full length of the side having the cutout portion was calculated, and the value was used as the ratio of the area where the missing portion was formed.

[Removability test]

Using the optical films obtained in Examples and Comparative Examples, a test to confirm the peelability of the surface protective film was performed. First, the peeling film was peeled from the optical film, and the exposed polarizing plate adhesive layer was attached to a glass plate (EAGLE XG, manufactured by CORNING) as a test sample. In the obtained For the test sample, a peeling tape (Cello-Tape (registered trademark), manufactured by NICHIBAN Co., Ltd.) was attached to the surface of the optical film on the surface protection film side. For the peeling tape, a width of 10 mm, a length of 30 mm, and an adhesive portion within the entire length of 15 mm from one end in the longitudinal direction are used. The whole adhesive part of the peeling tape is attached to the surface of the surface protective film of the optical film, and is installed at the position where the notch is formed of the optical film so as to cross the edge where the notch is formed (the symbol " 39” indicates the location). The part of the peeling tape that protrudes from the end of the optical film to the outside is fixed to the peeling device (high-speed peeling device TJ95, manufactured by Honda Manufacturing Co., Ltd.) at an angle (peeling angle) of 90° with respect to the surface direction of the optical film. )'S aids. The holding position of the peeling tape fixed to the auxiliary tool was set to a position 5 mm away from the end of the peeling tape on the side opposite to the adhesion portion in the longitudinal direction. Subsequently, the auxiliary tool of the peeling device was moved at a speed of 30 mm/sec from the side to which the peeling tape was attached to the side of the optical film facing the side facing the side. Three optical films were prepared for each of the examples and comparative examples, and the above-mentioned peelability test was performed on the three optical films to measure the number of times the surface protective film was peeled off.

[Measurement of peel force]

The optical films obtained from the examples and comparative examples were cut into 25mm-wide rectangles without deficiencies to obtain measurement samples, and the precision universal testing machine "AUTOGRAPH AGS-50NX" manufactured by Shimadzu Corporation was used. The polarizing plate and the surface protective film of the measurement sample are fixed and the force when peeling in the direction of 180° is measured and obtained. The measurement of the peeling force was performed at a peeling speed of 300 mm/min, an environment of a temperature of 23±2° C., and a relative humidity of 50±5%.

[Example 1]

(Manufacture of polarizing slab film)

The water-based adhesive used when manufacturing the polarizing plate is prepared in the following procedure. Dissolve 3 parts of carboxy-modified polyvinyl alcohol (trade name "KL-318", manufactured by Kuraray Co., Ltd.) in 100 parts of water, and add a polyamide epoxy-based additive (trade name "Sumirez Resin 650 (trade name) 30)" (water-soluble epoxy resin, aqueous solution with a solid concentration of 30%), manufactured by Taoka Chemical Industry Co., Ltd.) 1.5 parts to prepare an aqueous adhesive.

Next, using the water-based adhesive prepared above, a protective film green film A (thickness: 23 μm) composed of a cyclic olefin-based resin film was bonded to one side of the polarizing film green film with a thickness of 8 μm, and the above-mentioned prepared A water-based adhesive is used to bond a protective film green film B (thickness: 52 μm) composed of a cyclic olefin resin film with a hard coat layer to the other surface of the polarizer green film to obtain a protective film green film A/ Polarizing plate/protective film blank film B layer structure polarizing plate blank film. The thickness of the obtained polarizing slab film was 83 μm.

(Manufacture of optical film)

An adhesive layer (manufactured by LINTEC Co., Ltd.) was applied on one side of a release film film (thickness: 38 μm) composed of a polyethylene terephthalate film to form an adhesive layer for polarizing plates with a thickness of 20 μm. The polarizing plate adhesive layer of the peeling film green film was bonded to the protective film green film A side of the polarizing film green film. In addition, the surface protection film blank film (trade name "AS3-304", manufactured by Fujimori Industries Co., Ltd. [who formed an adhesive layer with a thickness of 20 μm on a polyethylene terephthalate film with a thickness of 38 μm]) The agent layer is bonded to the protective film green film B side of the polarizing plate green film to produce an optical film green film. The peeling force of the optical film blank film was 0.07N/25mm.

From the obtained optical film blank film, a rectangular blade-shaped optical film having a long side of 150 mm and a short side of 70 mm was cut, and the blade-shaped optical films were stacked to obtain a laminate W (FIG. 3 ).

Cutting the end face of the obtained laminate W to obtain the plane shown in FIG. 8 Shape optical film. The cutting process is performed using the cutting device shown in FIG. 3, and the rotation speed of the cutting rotating bodies 45 and 46 and the moving speed of the laminate W are adjusted to adjust the distance L1 of the missing portion. As shown in FIG. 8, the obtained optical film has concave cutouts on one short side and the corners of the concave cutouts are also R-processed. The width of the notch portion (the length of the portion indicated by h1 in FIG. 8) is 30 mm, and the depth of the notch portion (the length of the portion indicated by h2 in FIG. 8) is 10 mm.

With respect to the obtained optical film, the distance L1 of the missing part was measured, the area where the missing part was formed was calculated, and the peelability test was performed. The results are shown in Table 1.

[Examples 2 to 4, Comparative Examples 1 and 2]

Except for the adjustment of the rotational speed of the cutting rotors 45 and 46 and the moving speed of the laminate W at the cutting process using the cutting apparatus, the distance L1 of the missing part is changed as shown in Table 1, and the rest is the same as Example 1. The same procedure was performed to obtain an optical film having the same outer shape as in Example 1. With respect to the obtained optical film, the distance L1 of the missing part was measured, the area where the missing part was formed was calculated, and the peelability test was performed. The results are shown in Table 1.

10‧‧‧Optical film

10a to 10d ‧‧‧ side

11‧‧‧Notch

12‧‧‧Defective Department

20‧‧‧ Polarizer

30‧‧‧Surface protective film

31‧‧‧ Base layer

32‧‧‧Adhesive layer

L1‧‧‧Distance

Pab, Pbc, Pcd, Pda

Claims (12)

An optical film includes a polarizing plate and a surface protective film that can be peelably attached to a surface of the polarizing plate, wherein, The aforementioned surface protection film has a base material layer and an adhesive layer, In a plan view, the optical film is a square or a rounded square with a cutout on at least one side. The optical film has a defect portion formed by making at least the surface end of the adhesive layer on the polarizing plate side 15 μm or more inward from the end of the base material layer, The deficiencies are formed on at least a part of one side of the cutout. The optical film according to item 1 of the patent application range, wherein the optical film of the cutout portion has a concave shape recessed toward a side facing the side having the cutout portion when the optical film is viewed from above. The optical film according to item 1 or 2 of the patent application range, wherein the square or rounded square is a rectangle or a rounded rectangle, and one side having the cut-out portion is at least one of short sides. The optical film according to item 2 or 3 of the patent application range, wherein the deficiencies are formed in a range of 15% or more of the length of one side of the cutout. The optical film according to any one of claims 2 to 4, wherein the deficiencies are continuously formed in a range of 15% or more of the length of one side of the cutout. The optical film according to any one of claims 1 to 5, wherein the optical film further has a hole portion, and the deficiencies are further formed in at least a part of the surrounding portion of the hole portion. The optical film as described in item 6 of the patent application range, wherein the deficiencies are formed in at least one side having the notch in the peripheral portion of the hole. An optical film includes a polarizing plate and a surface protective film that can be peelably attached to a surface of the polarizing plate, wherein, The aforementioned surface protection film has a base material layer and an adhesive layer, The aforementioned optical film system has: a hole, and A defect portion formed by at least a surface end portion of the adhesive layer on the polarizing plate side 15 μm or more inward from the end portion of the base material layer, The deficiencies are formed in at least a part of the surrounding portion of the hole. The optical film according to any one of claims 6 to 8, wherein the deficiencies are formed all around the hole. The optical film according to any one of claims 1 to 9, wherein the deficiencies are such that the surface end of the adhesive layer on the polarizing plate side is closer to the substrate than the adhesive layer The area where the surface end on the layer side is formed closer to the inside. The optical film according to any one of claims 1 to 10, wherein the peeling force between the polarizing plate and the surface protective film is 0.10 N/25 mm or less. The optical film according to any one of claims 1 to 11, wherein the optical film has a polarizing plate adhesive layer on the polarizing plate side.

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