TWI825233B - Method for manufacturing optical laminate with adhesive layer processed by cutting - Google Patents

Abstract

The present invention provides a method for manufacturing an optical laminate with an adhesive layer that has been machined in a simple and low-cost manner. The peeling failure of the surface protective film of the optical laminate with an adhesive layer that has been machined is suppressed and the cutting surface is tapered. The situation has been suppressed. The manufacturing method of the cut optical laminate with an adhesive layer of the present invention includes: stacking a plurality of optical laminates with an adhesive layer to form a workpiece; using an end mill with a spiral blade to cut the outer peripheral surface of the workpiece; And, use an end mill with an edge angle of 0° to further cut the outer peripheral surface of the cut workpiece. The optical laminate with adhesive layer includes an optical film, an adhesive layer, a separator and a surface protection film. The adhesive layer is arranged on one side of the optical film. The separator is temporarily adhered to the adhesive layer in a peelable state. The protective film is temporarily adhered to the other side of the optical film in a peelable state. The manufacturing method of the present invention forms a workpiece by stacking an adhesive layer optical laminate such that the separator is positioned in the chip discharge direction of an end mill with a spiral blade.

Description

Method for manufacturing optical laminate with adhesive layer processed by cutting

The present invention relates to a method for manufacturing an optical laminate with an adhesive layer that is processed by cutting.

Image display devices such as mobile phones and notebook personal computers use various optical laminates (such as polarizing plates) in order to realize image display and/or improve the image display performance. Typically, an adhesive layer is provided as the outermost layer on an optical laminate, so that the optical laminate can be bonded to an image display device. During actual use, a separable piece is temporarily adhered to the adhesive layer in a peelable state, which can protect the adhesive layer until actual use. Furthermore, a surface protection film is temporarily adhered in a releasable state to the side representative of the optical laminate opposite to the adhesive layer. In recent years, it has been desired to process the shape of an optical laminate into a desired shape. The processing method includes, for example, end face cutting using an end mill.

Prior technical literature patent documents Patent document 1: Japanese Patent Application Publication No. 2018-22140

The problem to be solved by the invention Here, when the optical laminate is bonded to other optical members, the surface protective film is required to have easy peelability (hereinafter, it may only be referred to as peelability). Furthermore, when end milling is performed using an end mill, the cutting surface may become tapered when viewed from the side. The present invention was made in order to solve the above-mentioned problems, and its main purpose is to provide a method that can easily and cheaply produce a machined optical laminate with an adhesive layer attached. The machined optical laminate with an adhesive layer has a The peeling failure of the surface protective film is suppressed, and the tapering of the cutting surface is suppressed.

means to solve problems The manufacturing method of the cut optical laminate with an adhesive layer of the present invention includes: stacking a plurality of optical laminates with an adhesive layer to form a workpiece; and using an end mill with a spiral blade to cut the outer peripheral surface of the workpiece. ; and, use an end mill with an edge angle of 0° to further cut the outer peripheral surface of the cut workpiece. The adhesive layer-attached optical laminate includes an optical film, an adhesive layer, a separator and a surface protection film. The adhesive layer is arranged on one side of the optical film, and the separator is temporarily adhered to the adhesive in a peelable state. agent layer, and the surface protection film is temporarily adhered to the other side of the optical film in a peelable state. The manufacturing method of the present invention is to form the workpiece by stacking the adhesive layer optical laminate in such a manner that the separator is located in the chip discharge direction of the end mill with a spiral blade. In one embodiment, the end mill with a spiral blade is a right-edge right-edge helical or a left-edge helical left-edge, and the adhesive layer optical laminate is laminated so that the separator is on the upper side to form a workpiece. . In another embodiment, the end mill having a spiral blade is a right-edge left-hand spiral or a left-edge right-edge spiral, and the adhesive layer optical laminate is stacked such that the separation member is located on the lower side, and form an artifact. In one embodiment, the cutting amount achieved by using the end mill with a spiral edge is 0.1 mm to 0.5 mm, and the cutting amount using the end mill with an edge angle of 0° is 0.01 mm to 0.2 mm. In one embodiment, the above-mentioned manufacturing method produces relief on the above-mentioned surface protection film by cutting with the above-mentioned end mill having a spiral blade. In one embodiment, the embossment amount of the surface protection film is 1 μm to 1000 μm. In one embodiment, the manufacturing method includes non-linear cutting of the outer peripheral surface of the workpiece. In one embodiment, the non-linear cutting includes forming a recessed portion including a curved portion when the adhesive layer optical laminate is viewed from above. In one embodiment, the radius of the curved portion is 5 mm or less. In one embodiment, the optical film is a polarizer or polarizing plate.

Invention effect According to the present invention, there is a method for manufacturing an optical laminate with an adhesive layer. The method includes: stacking a plurality of optical laminates with an adhesive layer to form a workpiece, and using an end mill to cut the outer peripheral surface of the workpiece; In addition, after cutting the outer peripheral surface using an end mill with a spiral blade, the cutting surface is further cut using an end mill with a blade angle of 0° in such a manner that the separator is located in the chip discharge direction of the end mill with a spiral blade. By stacking the adhesive layer-attached optical laminate to form a workpiece, and cutting the formed workpiece, a method for manufacturing the machined adhesive layer-attached optical laminate can be realized easily and at low cost. The peeling failure of the surface protective film of the adhesive layer optical laminate is suppressed, and the tapering of the cutting surface is suppressed.

Specific embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments. In addition, the drawings are shown schematically for ease of viewing, and ratios such as length, width, thickness, and angles in the drawings may differ from the actual ones.

The manufacturing method of the adhesive layer-attached optical laminate of the present invention includes: stacking a plurality of adhesive layer-attached optical laminates to form a workpiece; using an end mill with a spiral blade to cut the outer peripheral surface of the workpiece; and, The outer peripheral surface of the cut workpiece is further cut using an end mill with an edge angle of 0°. The optical laminate with adhesive layer includes an optical film, an adhesive layer, a separator and a surface protection film. The adhesive layer is arranged on one side of the optical film. The separator is temporarily adhered to the adhesive layer in a peelable state. The protective film is temporarily adhered to the other side of the optical film in a peelable state. In an embodiment of the present invention, the adhesive layer optical laminate is stacked so that the separator is located in the chip discharge direction of the end mill with a spiral blade to form the workpiece. For convenience, the specific structure of the adhesive layer optical laminated body that can be used in the manufacturing method of the adhesive layer optical laminated body of the present invention will be described first, and then the manufacturing method of the adhesive layer optical laminated body of the present invention will be described.

A. Optical laminate with adhesive layer FIG. 1 is a schematic cross-sectional view illustrating an example of an optical laminate with an adhesive layer that can be used in the manufacturing method of the present invention. The optical laminate 100 with an adhesive layer in the illustrated example includes an optical film 10, an adhesive layer 20, a separator 30 and a surface protection film 40. The adhesive layer 20 is disposed on one side of the optical film 10, and the separator 30 is removable. The peelable state is temporarily adhered to the adhesive layer 20, and the surface protection film 40 is temporarily adhered to the other side of the optical film 10 in a peelable state. When the optical laminate with an adhesive layer is used in an image display device, it means that the upper separation member 30 is disposed on the image display unit side. When the optical laminate with an adhesive layer is actually used, the separator 30 will be peeled off and removed, and the adhesive layer 20 can be used to bond the optical laminate with an adhesive layer to an image display device (essentially, an image display unit). The surface protection film 40 is representatively provided with a base material 41 and an adhesive layer 42 . In addition, in order to distinguish the adhesive layer 20, the adhesive layer 42 of the surface protection film is sometimes called a "PF adhesive layer". The surface protection film 40 will also be peeled off and removed when the adhesive layer optical laminate is actually used. In an embodiment of the present invention, by adopting a manufacturing method as described below, it is possible to realize a cut-processed optical laminate with an adhesive layer in which peeling failure of the surface protective film is suppressed. That is, according to the embodiment of the present invention, it is possible to suppress the problems unique to the adhesive layer-attached optical laminate including the adhesive layer, the separator and the surface protective film, that is, it is possible to suppress the peeling failure of the surface protective film.

The optical film 10 can be any suitable optical film that can be used for applications requiring cutting processing (especially non-linear processing). The optical film may be a single-layer film or a laminated body. Specific examples of optical films composed of a single layer include polarizers and retardation films. Specific examples of optical films composed of laminates include polarizing plates (typically, laminates of polarizers and protective films), conductive films for touch panels, surface treatment films, and single layers composed of these depending on the purpose. The optical film and/or the optical film in the form of a laminate is appropriately laminated to form a laminate (for example, a circular polarizing plate for anti-reflection, a polarizing plate with a conductive layer for touch panels).

The adhesive layer 20 can adopt any suitable structure. Specific examples of the adhesive constituting the adhesive layer include acrylic adhesives, rubber adhesives, silicone adhesives, polyester adhesives, urethane adhesives, epoxy adhesives and polyester adhesives. Ether adhesive. By adjusting the monomer type, quantity, combination and blending ratio of the base resin forming the adhesive, as well as the blending amount of the cross-linking agent, reaction temperature, reaction time, etc., an adhesive with the desired characteristics according to the purpose can be prepared. agent. The base resin of the adhesive can be used alone or in combination of two or more types. An acrylic adhesive is suitable from the viewpoint of transparency, processability, and durability. Details of the adhesive constituting the adhesive layer are described in, for example, Japanese Patent Application Laid-Open No. 2014-115468, and the description of this publication is used as a reference in this specification. The thickness of the adhesive layer 20 may be, for example, 10 μm ~ 100 μm. The storage elastic modulus G' of the adhesive layer 20 at 25°C may be, for example, 1.0×10 ⁴ (Pa) to 1.0×10 ⁶ (Pa). In addition, the storage elastic modulus can be obtained by dynamic viscoelasticity measurement, for example.

The separation member 30 may be any suitable separation member. Specific examples include plastic films, nonwoven fabrics, or paper surface-coated with a release agent. Specific examples of the release material include silicone release agents, fluorine release agents, and long-chain alkyl acrylate release agents. Specific examples of the plastic film include polyethylene terephthalate (PET) film, polyethylene film, and polypropylene film. The thickness of the separation member may be, for example, 10 μm ~ 100 μm.

The surface protection film 40 is representatively provided with a base material 41 and an adhesive layer 42 as described above. Examples of materials for forming the base material 41 include ester resins such as polyethylene terephthalate resin, cycloolefin resins such as norbornene resin, olefin resins such as polypropylene, polyamide resins, and polycarbonate. Ester resin and its copolymer resin, etc. More preferred are ester resins (especially polyethylene terephthalate resins). As long as it is the above-mentioned material, it has the advantage of having a sufficiently high elastic modulus and not easily deforming even if tension is applied during transportation and/or lamination.

The elastic modulus of the base material 41 may be, for example, 2.2kN/mm ² ~4.8kN/mm ² . As long as the elastic modulus of the base material is within the above range, it has the advantage that it is less likely to deform even if tension is applied during transportation and/or lamination. In addition, the elastic modulus is measured in accordance with JIS K 6781.

The thickness of the base material 41 is, for example, 30 μm to 70 μm.

The adhesive layer (PF adhesive layer) 42 may have any appropriate structure. Specific examples include acrylic adhesives, rubber adhesives, silicone adhesives, polyester adhesives, urethane adhesives, epoxy adhesives, and polyether adhesives. By adjusting the monomer type, quantity, combination and blending ratio of the base resin that forms the adhesive, as well as the blending amount of the cross-linking agent, reaction temperature, reaction time, etc., an adhesive with desired characteristics corresponding to the purpose can be prepared. agent. The base resin of the adhesive can be used alone or in combination of two or more types. The adhesive constituting the PF adhesive layer has the following characteristics: the base resin contains a polymer having a functional group containing active hydrogen. As long as the base resin is used, a PF adhesive layer with a desired storage elastic modulus can be obtained. Details of the adhesive constituting the PF adhesive layer are described in, for example, Japanese Patent Application Laid-Open No. 2018-123281, and the description of this publication is used as a reference in this specification. The thickness of the PF adhesive layer 42 may be, for example, 10 μm ~ 100 μm. The storage elastic modulus G' of the PF adhesive layer 42 at 25°C may be, for example, 0.5×10 ⁶ (Pa) to 3.0×10 ⁶ (Pa). As long as the storage elastic modulus is within the above range, an adhesive layer (resulting in a surface protective film) with excellent balance between adhesiveness and peelability can be obtained. In addition, the surface protection film can be embossed through the manufacturing method described below. As a result, the embossed portion can be used as a gripping edge to easily concentrate stress on the peeling point. Therefore, better peeling can be achieved while maintaining acceptable adhesion. sex.

The thickness of the surface protection film 40 may be, for example, 40 μm ~ 120 μm. In addition, the thickness of the surface protection film refers to the total thickness of the base material and PF adhesive layer.

In one embodiment, the peeling force of the separator 30 and the adhesive layer 20 (hereinafter also referred to as the peeling force of the separator) is greater than the peeling force of the optical film 10 and the surface protection film 40 (essentially the PF adhesive layer 42) ( (Hereinafter also referred to as the peeling force of the surface protection film) is smaller. In most cases, the peeling force of the surface protection film is greater than the peeling force of the separator, and peeling failure of the surface protection film is likely to occur. However, according to the manufacturing method described below, it is possible to obtain a machined attachment in which peeling failure of the surface protection film is suppressed. Adhesive layer optical laminate. More specifically, the peeling force of the separation part should be 0.001N/10mm~1.0N/10mm, and the peeling force of the surface protection film should be 0.01N/10mm~5.0N/10mm. The peeling force of the separation part should be 0.001~0.1N/10mm, more preferably 0.005~0.03N/10mm. The peeling force of the surface protection film should be 0.01~0.5N/10mm, more preferably 0.035~0.1N/10mm. The difference between the peeling force of the separation element and the peeling force of the surface protection film (peeling force of the surface protection film - the peeling force of the separation element) should be 0.01N/10mm~1.0N/10mm. According to the manufacturing method described below, even if the peeling force has the above-mentioned difference, it is possible to obtain a cutting-processed adhesive layer optical laminate in which peeling failure of the surface protective film is suppressed.

In one embodiment, the thickness of the surface protection film 40 is greater than the thickness of the separation member 30 . By using the above manufacturing method, even when the thickness of the general surface protection film is very thick and a large peeling force is required, excellent peelability can be achieved. The difference between the thickness of the surface protection film and the thickness of the separation piece (thickness of the surface protection film - thickness of the separation piece) is preferably 5 μm ~ 60 μm. According to the manufacturing method described below, even if there is the above-mentioned difference in thickness, it is possible to obtain a cutting-processed adhesive layer optical laminate in which peeling failure of the surface protective film is suppressed.

B. Manufacturing method of optical laminate with adhesive layer Hereinafter, a typical example of a method of manufacturing an optical laminate with an adhesive layer will be described. First, the relationship between the structure of the end mill having a spiral blade and the lamination state of the workpiece, which is a characteristic part of the present invention, will be explained, and then the outline of the manufacturing method will be explained.

B-1. The relationship between the structure of the end mill and the lamination state of the workpiece In the embodiment of the present invention, as described above, the adhesive layer optical laminate is stacked so that the separator is located in the chip discharge direction of the end mill with a spiral blade to form a workpiece, and then the outer peripheral surface of the workpiece is cut. Detailed description will be given with reference to FIGS. 2 and 3 . FIG. 2 is a schematic diagram illustrating a representative example of the structure of an end mill having a spiral blade that can be used in the manufacturing method of the present invention. FIG. 3 is a schematic plan view illustrating the difference in cutting direction between when the end mill having a spiral cutting edge is a right-side cutting edge and when it is a left-side cutting edge. As shown in Figure 2, the structure of the end mill with a spiral edge is roughly divided into right-edge right-edge helical, right-edge left-edge helical, left-edge right-edge helical, and left-edge left helical. As shown in Figure 2, the so-called right blade refers to a structure that can be cut when rotated clockwise when viewed from the upper side (shank side); the so-called left blade refers to a structure that can be cut counterclockwise when viewed from the upper side (shank side). composition. As further shown in Figure 2, the so-called right-hand spiral refers to the structure in which the blade extends obliquely upward when viewed from the side; the so-called left-hand spiral refers to the structure in which the blade extends obliquely upward leftward when viewed from the side. The discharge direction of chips for right-edge right-edge helix and left-edge left-edge helix is upward; for right-edge left-edge helix and left edge right-edge helix, the discharge direction of chips is downward. In addition, as shown in Figure 3, the cutting direction of the right blade is represented by counterclockwise rotation, and the cutting direction of the left blade is represented by clockwise rotation.

In the embodiment of the present invention, as described above, the adhesive layer optical laminate is stacked so that the separator is located in the chip discharge direction of the end mill with a spiral blade to form a workpiece, and then the outer peripheral surface of the workpiece is cut. For example, when the end mill with a spiral edge is right-edge helical or left-edge helical, the adhesive layer optical laminate is stacked so that the separator is on the upper side as shown in Figure 4(a). Artifact W. On the other hand, when the end mill has a right-edge left-hand spiral or a left-edge right-edge spiral, the adhesive layer optical laminate is stacked so that the separator is on the lower side as shown in Figure 4(b). Artifact W. The present inventors discovered that depending on the relationship between the chip discharge direction of an end mill with a spiral blade and the arrangement of the surface protective film of the adhesive layer optical laminate in the workpiece, embossing may occur in the surface protective film. The problem of poor peeling of the surface protective film can be solved by causing the surface protective film to be embossed. As long as the structure is as described above, the adhesive layer optical laminate is shaved (or shaved) from the surface protection film side to the separation member side. As a result, a surface protection film that is given strong cutting force in an oblique direction can be produced. embossed. This makes it possible to obtain a cutting-processed optical laminate with an adhesive layer in which peeling failure of the surface protective film is suppressed. The amount of relief of the surface protection film is preferably 1 μm or more, more preferably 20 μm or more, and more preferably 50 μm or more. On the other hand, the amount of relief is preferably 1000 μm or less, more preferably 500 μm or less. As long as the amount of relief is within the above range, good peelability of the surface protective film can be achieved without causing other problems and maintaining the appearance quality within an acceptable range. Embossing will reduce the appearance quality, so the industry tries to avoid its occurrence as much as possible. However, according to the embodiment of the present invention, by actively embossing the surface protection film, which is a technical idea that completely goes against the technical common sense of the industry, it is possible to obtain An optical laminate with an adhesive layer that has been machined and has suppressed peeling defects. In addition, if the relationship between the structure of the end mill with a spiral blade and the lamination state of the workpiece is reversed (that is, if the end mill with a spiral blade is a right-edge right-edge helical or a left-edge left-edge helical as shown in Figure 4(b) The workpiece is formed as shown in Figure 4(a)), and when the end mill with a spiral edge is a right-edge left-hand spiral or a left-edge right-edge spiral, the workpiece is formed as shown in Figure 4(a)), the separation part will be embossed but the surface protection film will not Produce relief. As a result, the problem of poor peeling of the surface protective film may not be eliminated.

B-2. Form workpiece Next, the outline of cutting processing will be described. FIG. 5 is a schematic perspective view for explaining the cutting process of the manufacturing method of the present invention. In this figure, the workpiece W is shown. As shown in FIG. 5 , a workpiece W is formed in which a plurality of optical laminates with adhesive layers are laminated. As explained in Section B-1, the lamination state of the workpiece W is set as shown in Figure 4(a) or Figure 4(b) in accordance with the structure of the end mill having a spiral edge. When the optical laminate with an adhesive layer is formed into a workpiece, it is typically cut into any appropriate shape. Specifically, the adhesive layer optical laminate can be cut into a rectangular shape, a shape similar to a rectangular shape, or an appropriate shape (for example, a circle) according to the purpose. The workpiece W has outer peripheral surfaces (cutting surfaces) 1a and 1b facing each other and outer peripheral surfaces (cutting surfaces) 1c and 1d orthogonal to these. The workpiece W should be clamped from top to bottom by a clamping mechanism (not shown). The total thickness of the workpiece should be 8mm~20mm, and preferably 9mm~15mm, and more preferably about 10mm. As long as it is the above thickness, damage caused by extrusion of the clamp mechanism or impact during cutting can be prevented. The adhesive layer optical lamination system laminated the workpiece to the stated total thickness. The number of sheets of the adhesive layer-attached optical laminate constituting the workpiece may be, for example, 10 to 50 sheets. The clamping mechanism (such as a clamp) can be made of soft material or hard material. When made of soft material, its hardness (JIS A) should be 60°~80°. If the hardness is too high, there will be residual indentations caused by the clamping mechanism. If the hardness is too low, the deformation of the fixture will cause position deviation, resulting in insufficient cutting accuracy.

B-3. Cutting processing B-3-1. Cutting using end mills with spiral edges Next, the outer peripheral surface of the workpiece W is cut using the end mill 60 having a spiral blade. Cutting is typically performed by bringing the cutting edge of the end mill into contact with the outer peripheral surface of the workpiece W. Cutting can cover the entire outer circumference of the workpiece, or it can only be done at a predetermined position.

As shown in FIG. 6 , the end mill 60 with a spiral blade has a rotation axis 61 extending in the lamination direction (vertical direction) of the workpiece W, and a cutting edge 62 configured as a body that rotates around the rotation axis 61 . its outermost diameter. In the illustrated example, the cutting edge 62 is configured as the outermost diameter twisted along the rotation axis 61, and is shown as a right-edge right-hand helix. The cutting edge 62 includes a cutting edge 62a, a rake surface 62b and a flank surface 62c. The number of cutting edges 62 can be appropriately set according to the purpose. In the illustrated example, the cutting blades are composed of 3 blades, but the number of blades can be 1 continuous blade, 2 blades, 4 blades, or 5 or more blades. The edge angle of the end mill (the helix angle θ of the cutting edge in the example in the figure) is preferably 20°~60°, and 30°~45° is better. As long as the blade angle is as described above, the surface protective film can be well embossed by cutting. The surface behind the cutting edge should be roughened. Any suitable treatment may be used for the roughening treatment. A representative example is sandblasting. By roughening the flank surface, the adhesion of adhesive to the cutting edge can be suppressed, and as a result, sticking can be suppressed. The outer diameter of the end mill should be 3mm~20mm. In addition, the so-called "adhesion" in this specification refers to the phenomenon that the optical laminates with adhesive layers on the workpiece are connected to each other due to the adhesive on the end surfaces. The chips of the adhesive attached to the end surfaces will promote the adhesion of the optical laminates with adhesive layers to each other. In addition, the "outer diameter of the end mill" means multiplying the distance from the rotation axis 61 to the blade edge 62a by twice. The end mill can be a single-sided fixed end mill with one end (upper end) fixed, or a double-sided fixed end mill with both ends (upper end and lower end) fixed.

In the embodiment of the present invention, the cutting performed by the end mill having a spiral blade may be equivalent to so-called rough cutting. First, use an end mill with a spiral blade for cutting, and then use an end mill with a blade angle of 0° to further cut (finish) the cutting surface as described later. This can prevent peeling defects of the surface protective film. , and can prevent the cutting surface from becoming tapered. The cutting amount caused by using an end mill with a spiral blade should be about 0.1mm~0.5mm.

B-3-2. Cutting using an end mill with an edge angle of 0° In the embodiment of the present invention, after cutting with an end mill having a spiral blade, the cutting surface is further cut with an end mill with a blade angle of 0° as shown in FIG. 7 . This can be equivalent to so-called fine cutting. As long as the structure is as described above, peeling failure of the surface protective film can be suppressed, and the cutting surface can be suppressed from becoming tapered. More specifically, by cutting in a predetermined pattern using an end mill with a spiral blade, the surface protective film is embossed as described in the above item B-1, thereby suppressing peeling failure of the surface protective film. On the other hand, when cutting with an end mill with a spiral edge, the cutting surface becomes tapered. However, by further cutting the cutting surface with an end mill with an edge angle of 0°, the tapering can be eliminated. The cutting surface. In addition, on the cutting surface side of the adhesive layer optical laminate using an end mill with a spiral blade, the relief of the surface protection film may cause unacceptable deterioration in appearance quality, but by using a blade angle of 0° Cutting with an end mill can remove the part with reduced appearance quality. Furthermore, by cutting with an end mill with a blade angle of 0°, the amount of relief of the surface protection film produced by cutting with an end mill with a spiral blade can be appropriately adjusted. The cutting amount obtained by using an end mill with an edge angle of 0° should be about 0.01mm~0.2mm. The cutting amount performed by an end mill with an edge angle of 0° is a finishing cut, and its cutting amount is typically significantly smaller than the cutting amount (cutting amount of rough cutting) caused by an end mill with a spiral edge. Thereby, the amount of relief of the surface protection film can be appropriately adjusted, and as a result, good peelability of the surface protection film can be achieved without causing other adverse effects and maintaining the appearance quality within an acceptable range. In addition, a highly versatile end mill with a spiral blade can contribute to most cutting operations, so the manufacturing method of the present invention is also advantageous from a cost perspective. In addition, the so-called "blade angle 0°" in this specification means that the blade edge 62a extends in a direction substantially parallel to the rotation axis. In other words, it means that the blade is not twisted toward the rotation axis. In addition, "0°" means substantially 0°, and also includes cases where there is slight angle rotation due to processing errors, etc. In addition, the so-called "tapered cutting surface" means that when the cutting surface is viewed from the lateral direction, the cutting surface is offset and extended from the vertical direction to the diagonal direction.

B-3-3.Others In one embodiment, the manufacturing method of the present invention includes: non-linear cutting of the outer peripheral surface of the workpiece. Non-linear cutting includes, for example, as shown in FIG. 8 , forming a recessed portion 4 c including a curved portion when the adhesive layer optical laminated body is viewed from above. To produce an adhesive layer optical laminate with a plan view shape as shown in Figure 8, the outer periphery of the workpiece is linearly cut, and chamfered portions 4a and 4b are formed at two corners of the outer periphery of the workpiece. A concave portion (a concave portion including a curved portion) 4c is formed in the center of the outer peripheral surface of the corner portions 4a and 4b. By forming the recessed portion, the surface protection film can be embossed near the recessed portion. As a result, the peelability when peeling and removing the surface protective film from the recessed portion can be improved. An example of the cutting process will be described with reference to Figures 9(a) to 9(c). First, as shown in FIG. 9(a) , the part where the chamfered part 4a of FIG. 8 is to be formed is chamfered, and then as shown in FIG. 9(b) , the part where the chamfered part 4b is to be formed is chamfered. Finally, as shown in FIG. 9(c) , a concave portion (a concave portion including a curved portion) 4c is formed by cutting. The radius of the curved portion is preferably 5 mm or less, more preferably 4 mm or less, and more preferably 3 mm or less. In addition, the formation order (cutting order) of the chamfered portions 4a and 4b and the recessed portion 4c is not limited, and they can be formed in any appropriate order.

The cutting conditions can be appropriately set according to the desired shape. The rotational speeds of end mills with spiral edges and end mills with an edge angle of 0° are preferably 1000rpm~60000rpm and 10000rpm~40000rpm respectively. The feed speeds of end mills with spiral edges and end mills with an edge angle of 0° should be 500mm/min ~ 10000mm/min respectively, and more preferably 500mm/min ~ 2500mm/min. The number of cuts at the cutting point can be 1 cut, 2 cuts, 3 cuts or more.

In the above manner, an optical laminate with an adhesive layer that has been processed by cutting can be obtained. In the optical laminate with an adhesive layer obtained by the manufacturing method of the present invention, peeling failure of the surface protective film is suppressed, and tapering of the cutting surface is suppressed. Example

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited by these examples. The evaluation items of the examples are as follows.

(1) The incidence of embossment on the surface protection film Prepare any number (preferably more than 100) of optical laminates with adhesive layers after cutting, and use a magnifying glass or microscope to observe the relief of the surface protective film. Observe the entire circumference of each optical laminate with an adhesive layer. If embossments of more than 1 μm are observed, the optical laminate with an adhesive layer will be counted as a embossed sample and shall be determined by "(sample with embossment/ Observation number) × 100" to calculate the embossing production rate. (2) Peeling success rate Fifty pieces of the cut adhesive layer optical laminates obtained in Examples and Comparative Examples were randomly extracted, and the surface protective film was peeled off from each piece (initial peeling force 2.9N). The number of successful peelings without problems among 50 peelings is expressed as a percentage and is used as the peeling success rate. (3) Amount of relief The amount of relief of the surface protective film in the cut adhesive layer optical laminate obtained in Examples and Comparative Examples was measured using a magnifying glass or microscope. The maximum value of the relief amount of a workpiece is regarded as the relief amount. (4) cone A scanning electron microscope (SEM) was used to observe the cut surface of the polarizing plate with the adhesive layer obtained in the Example and the Comparative Example from the lateral direction (magnification: 500 times). The cutting surface viewed from the transverse direction is evaluated according to the following criteria. ○: The cutting surface extends substantially in the vertical direction ×: The cutting surface is offset from the vertical direction to the diagonal direction

>Example 1> According to the conventional method, a surface protective film (60μm)/cycloolefin-based protective film (47μm)/polarizer (5μm)/cycloolefin-based protective film (24μm)/adhesive layer (20μm) is produced from the viewing side. )/A polarizing plate with an adhesive layer composed of a separable component. In addition, a surface protection film composed of a PET base material (50 μm)/PF adhesive layer (10 μm) was produced and verified. At this time, the storage elastic modulus of the adhesive layer (adhesive) is adjusted to 0.5MPa~3.0MPa. After the polarizing plate with the adhesive layer obtained in the above method is punched into a size of 5.7 inches (about 140mm long and 65mm wide), multiple pieces of the punched polarizing plate are laminated to make a workpiece (total thickness is about 10mm). With the obtained workpiece clamped in a vise (clamp), chamfered portions are formed on two corners of the outer circumference of the workpiece using an end mill, and chamfered portions are formed in the center of the outer circumferential surface where the chamfered portion is formed. The concave portion (the concave portion including the curved portion) is obtained to obtain a polarizing plate with an adhesive layer attached through cutting as shown in Figure 8 . Cutting was performed twice: rough cutting and fine cutting. For rough cutting (the first cutting), a right-edge right-hand helical end mill with a helix angle of 30° is used (the chip discharge direction is upward), and the cutting amount is 0.2mm. Finish cutting (second cutting) uses an end mill with an edge angle of 0°, and the cutting amount is 0.1mm. The occurrence rate of embossment on the surface protection film caused by cutting is 100%. The above-mentioned evaluations (2) to (4) were performed on the obtained polarizing plate with an adhesive layer that was processed by cutting. The results are listed in Table 1.

>Example 2> Rough cutting (the first cutting) was performed in the same manner as in Example 1 except that an end mill with a right-edge right-hand helix and a helix angle of 45° was used. The obtained polarizing plate with the adhesive layer attached thereto was subjected to the same evaluation as in Example 1. The results are listed in Table 1.

>Comparative Example 1> The cutting process was performed in the same manner as in Example 1 except that finishing cutting (second cutting) using an end mill with an edge angle of 0° was not performed. The obtained polarizing plate with the adhesive layer attached thereto was subjected to the same evaluation as in Example 1. The results are listed in Table 1.

>Comparative example 2> The cutting process was performed in the same manner as in Example 2 except that finishing cutting (second cutting) using an end mill with an edge angle of 0° was not performed. The obtained polarizing plate with the adhesive layer attached thereto was subjected to the same evaluation as in Example 1. The results are listed in Table 1.

>Comparative Example 3> For rough cutting (the first cutting), an end mill with an edge angle of 0° is used, and for fine cutting (the second cutting), an end mill with a right-edge right-hand helix and a helix angle of 30° is used. Otherwise, it is as in the example. 1 Carry out cutting in the same way. The obtained polarizing plate with the adhesive layer attached thereto was subjected to the same evaluation as in Example 1. The results are listed in Table 1.

>Comparative Example 4> For rough cutting (the first cutting), an end mill with an edge angle of 0° is used, and for fine cutting (the second cutting), an end mill with a right-edge right-hand helix and a helix angle of 45° is used. Otherwise, it is as in the example. 2 Carry out cutting in the same way. The obtained polarizing plate with the adhesive layer attached thereto was subjected to the same evaluation as in Example 1. The results are listed in Table 1.

>Comparative Example 5> For both rough cutting (first cutting) and fine cutting (second cutting), an end mill with an edge angle of 0° was used, except that the cutting process was performed in the same manner as in Example 1. The obtained polarizing plate with the adhesive layer attached thereto was subjected to the same evaluation as in Example 1. The results are listed in Table 1.

>Comparative Example 6> For both rough cutting (first cutting) and fine cutting (second cutting), a right-edge right-hand helical end mill with a helix angle of 30° was used. Except for this, the cutting process was performed in the same manner as in Example 1. The obtained polarizing plate with the adhesive layer attached thereto was subjected to the same evaluation as in Example 1. The results are listed in Table 1.

>Comparative Example 7> For both rough cutting (first cutting) and fine cutting (second cutting), a right-edge right-hand helical end mill with a helix angle of 45° was used. Except for this, the cutting process was performed in the same manner as in Example 1. The obtained polarizing plate with the adhesive layer attached thereto was subjected to the same evaluation as in Example 1. The results are listed in Table 1.

>Comparative Example 8> The workpiece is formed by stacking the separate parts of the polarizing plate with the adhesive layer on the lower side. Except for this, the cutting process is performed in the same manner as in Example 1. The obtained polarizing plate with the adhesive layer attached thereto was subjected to the same evaluation as in Example 1. The results are listed in Table 1.

>Comparative Example 9> The workpiece is formed by stacking the separate parts of the polarizing plate with the adhesive layer on the lower side. Except for this, the cutting process is performed in the same manner as in Example 2. The obtained polarizing plate with the adhesive layer attached thereto was subjected to the same evaluation as in Example 1. The results are listed in Table 1.

[Table 1]

>Assessment> As can be seen from Table 1, according to an embodiment of the present invention, there is a method for manufacturing an optical laminate with an adhesive layer. The method includes: stacking multiple optical laminates with an adhesive layer to form a workpiece, and using an end mill. To cut the outer circumferential surface of the workpiece; in the manufacturing method of the optical laminate with an adhesive layer, an end mill with a spiral blade is used to cut the outer circumferential surface, and then an end mill with an edge angle of 0° is used to further cut the cut. surface, and the adhesive layer optical laminate is stacked so that the separator is located in the chip discharge direction of the end mill with a spiral blade to form a workpiece, and the formed workpiece is cut, thereby realizing a simple and low-cost method A method of cutting an optical laminate with an adhesive layer, in which peeling defects of the surface protective film of the optical laminate with an adhesive layer are suppressed, and tapering of the cut surface is suppressed.

industrial availability The manufacturing method of the present invention can be applied to manufacturing optical laminates with adhesive layers that require cutting processing (especially non-linear processing). The adhesive layer optical laminate obtained by the manufacturing method of the present invention can be applied to special-shaped image display parts represented by automobile instrument panels or smart watches.

W: workpiece 10: Optical film 20: Adhesive layer 30: Separate parts 40:Surface protection film 41:Substrate 42: Adhesive layer (PF adhesive layer) 60:End mill 61:Rotation axis 62:Cutting edge 62a:Blade 62b:Rake face 62c: flank surface 100: Optical laminate with adhesive layer 1a, 1b, 1c, 1d: outer peripheral surface (cutting surface) θ:Helix angle 4a,4b: Corner removal 4c: Concave part (concave part including curved part)

FIG. 1 is a schematic cross-sectional view illustrating an example of an optical laminate with an adhesive layer that can be used in the manufacturing method of the present invention. FIG. 2 is a schematic diagram illustrating a representative example of the structure of an end mill having a spiral blade that can be used in the manufacturing method of the present invention. 3 is a schematic plan view illustrating the difference in cutting direction between the right-hand cutting edge and the left-hand cutting direction of the end mill having a spiral cutting edge that can be used in the manufacturing method of the present invention. 4(a) is a schematic front view of important parts illustrating a method of forming a workpiece according to one embodiment of the present invention; (b) is a schematic front view of important parts illustrating a method of forming a workpiece according to another embodiment of the present invention. FIG. 5 is a schematic perspective view for explaining the cutting process in the manufacturing method of the present invention. FIG. 6 is a schematic diagram illustrating the structure of an end mill with a spiral blade used for cutting in the manufacturing method of the present invention. 7 is a schematic diagram for explaining the structure of an end mill with an edge angle of 0° used for cutting in the manufacturing method of the present invention. 8 is a schematic plan view showing an example of the shape of an optical laminate with an adhesive layer that can be obtained by cutting using the manufacturing method of the present invention. 9(a) to (c) are schematic top views illustrating a series of cutting processes in the manufacturing method of the present invention.

W: workpiece

10: Optical film

20: Adhesive layer

30: Separate parts

40:Surface protection film

100: Optical laminate with adhesive layer

Claims (9)

A method of manufacturing an optical laminate with an adhesive layer that has been processed by cutting, including: stacking multiple optical laminates with an adhesive layer to form a workpiece; using an end mill with a spiral blade to cut the outer peripheral surface of the workpiece; And, the outer peripheral surface of the cut workpiece is further cut using an end mill with an edge angle of 0°; the adhesive layer-attached optical laminate includes an optical film, an adhesive layer, a separator and a surface protection film, and the adhesive layer The agent layer is disposed on one side of the optical film, the separation member is temporarily adhered to the adhesive layer in a peelable state, and the surface protection film is temporarily adhered to the other side of the optical film in a peelable state; And the manufacturing method is to form the workpiece by stacking the adhesive layer optical laminate in such a way that the separator is located in the chip discharge direction of the end mill with a spiral blade, and by using the end mill with a spiral blade. The surface protection film is embossed by cutting with an end mill. The manufacturing method of claim 1, wherein the end mill with a spiral edge is a right-edge right-edge spiral or a left-edge left-edge spiral; and the manufacturing method is to optically superimpose the adhesive layer so that the separation member is located on the upper side. Laminated body to form a workpiece. The manufacturing method of claim 1, wherein the end mill with a spiral edge is a right-edge left-edge spiral or a left-edge right-edge spiral; and the manufacturing method is to superimpose the aforementioned adhesive layer in such a manner that the aforementioned separator is located on the lower side. The optical laminate forms the workpiece. For example, the manufacturing method of any one of claims 1 to 3, wherein the cutting amount caused by using the aforementioned end mill with a spiral edge is 0.1mm~0.5mm, and the cutting amount caused by using the aforementioned end mill with an edge angle of 0° The amount is 0.01mm~0.2mm. The manufacturing method according to any one of claims 1 to 3, wherein the aforementioned surface protection film The amount of relief is 1μm~1000μm. The manufacturing method of any one of claims 1 to 3, which includes: non-linear cutting of the outer peripheral surface of the workpiece. The manufacturing method of claim 6, wherein the non-linear cutting includes forming a recessed portion including a curved portion when the adhesive layer optical laminate is viewed from above. The manufacturing method of claim 7, wherein the radius of the aforementioned curved portion is less than 5 mm. The manufacturing method according to any one of claims 1 to 3, wherein the aforementioned optical film is a polarizer or a polarizing plate.

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