TW202043816A - Method for manufacturing machined optical laminate with attached adhesive layer - Google Patents

Abstract

The present invention provides a method which enables easy and low-cost manufacture of a machined optical laminate with an attached adhesive layer, whereby separation defects in a surface protection film are minimized. This method for manufacturing a machined optical laminate with an attached adhesive layer involves: forming a workpiece by layering a plurality of sheets of the optical laminate with an attached adhesive layer; and machining the outer peripheral surface of the workpiece using an end mill having a helical cutting edge. The optical laminate with an attached adhesive layer comprises an optical film, an adhesive layer disposed on one side of the optical film, a separator temporarily attached to the adhesive layer in a separable manner, and a surface protection film temporarily attached to the other side of the optical film in a separable manner. In this manufacturing method, the workpiece is formed by layering the optical laminate with an attached adhesive layer such that the separator is positioned in the discharge direction of cutting debris from the end mill.

Description

Method for manufacturing cut-processed optical laminate with adhesive layer

The invention relates to a method for manufacturing an optical laminate with an adhesive layer after cutting.

In order to realize image display and/or improve the image display performance of image display devices such as mobile phones and notebook personal computers, various optical laminates (for example, polarizing plates) are used. Representatively, the optical laminate is provided with an adhesive layer as the outermost layer, and the optical laminate can be bonded to the image display device. In actual use, a separation member is temporarily attached to the adhesive layer in a peelable state, which can protect the adhesive layer before actual use. In addition, a surface protective film is temporarily attached to the representative of the side of the optical laminate opposite to the adhesive layer in a peelable state. In recent years, it has been desired to process the shape of the optical laminate into a desired shape. The processing method may include, for example, end face cutting using an end mill.

Prior art literature Patent literature Patent Document 1: Japanese Patent Laid-Open No. 2018-22140

Problems to be solved by the invention Here, when bonding the optical layered body to another optical member, the easy peelability of the surface protection film is required (hereinafter, simply referred to as peelability). The present invention was made in order to solve the above-mentioned problems, and its main object is to provide a method of cutting an adhesive layer-attached optical laminate with suppressed peeling defects of a surface protective film easily and inexpensively.

Means to Solve the Problem The method for manufacturing a cutting-processed adhesive layer optical laminate of the present invention includes: stacking a plurality of adhesive layer optical laminates to form a workpiece; and using an end mill with a spiral blade To cut the outer peripheral surface of the workpiece. The adhesive layer 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 attached to the optical film in a peelable state. The adhesive layer, and the surface protection film is temporarily adhered to the other side of the optical film in a peelable state. In the manufacturing method of the present invention, the optical laminate with the adhesive layer is laminated so that the separator is positioned in the chip discharge direction of the end mill to form the workpiece. In one embodiment, the end mill is a right-edge right spiral or a left-edge left spiral, and the adhesive layer optical laminate is laminated so that the separating member is located on the upper side to form a workpiece. In another embodiment, the end mill is a right-blade left screw or a left-blade right screw, and the adhesive layer optical laminate is laminated so that the separator is positioned on the lower side to form a workpiece. In one embodiment, the peeling force of the separator and the adhesive layer is smaller than the peeling force of the optical film and the surface protection film. More specifically, the peeling force between the separator and the adhesive layer is 0.001N/10mm to 1.0N/10mm, and the peeling force between the optical film and the surface protection film is 0.01N/10mm to 5.0N/10mm. In one embodiment, the thickness of the surface protection film is greater than the thickness of the separator. In one embodiment, the above-mentioned surface protection film has a substrate and an adhesive layer, and the storage elastic modulus G'of the adhesive layer at 25° C. is 0.5×10 ⁶ (Pa)~3.0×10 ⁶ (Pa) . In one embodiment, in the manufacturing method, the surface protection film is embossed by the cutting. In one embodiment, the relief 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 concave portion including a curved portion when the optical laminate with an adhesive layer is formed in a plan view. In one embodiment, the radius of the curved portion is 5 mm or less. In one embodiment, the above-mentioned optical film is a polarizer or a polarizer.

Invention effect According to the present invention, a method for manufacturing an optical laminate with an adhesive layer is provided. The method includes: stacking a plurality of optical laminates with an adhesive layer to form a workpiece, and cutting the workpiece with an end mill with a spiral blade The outer peripheral surface; and the adhesive layer optical laminate is laminated so that the separating piece is located in the chip discharge direction of the end mill to form a workpiece, which can realize a simple and low-cost manufacturing of surface protection film. A method of suppressed cutting-processed optical laminates with adhesive layers.

The following describes specific embodiments of the present invention with reference to the drawings, but the present invention is not limited by these embodiments. In addition, the drawings are schematically shown for ease of viewing, and the ratios of length, width, thickness, etc., and angles in the drawings are different from actual ones.

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

A. Adhesive layer optical laminate 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 adhesive layer optical laminate 100 of the schematic 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 The peeled state is configured to be 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 applied to an image display device, it means that the upper separating member 30 is disposed on the side of the image display unit. The adhesive layer optical laminate will peel off the separator 30 during actual use, and the adhesive layer 20 can be used to attach the adhesive layer optical laminate to an image display device (essentially an image display unit). The surface protection film 40 typically has a substrate 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 referred to as "PF adhesive layer". The surface protection film 40 is also peeled off when the optical laminate with an adhesive layer is actually used. In the embodiment of the present invention, by adopting a manufacturing method as described later, a cutting-processed optical laminate with an adhesive layer with suppressed peeling defects of the surface protective film can be realized. That is, according to the embodiment of the present invention, the problems peculiar to the adhesive layer optical laminate including the adhesive layer, the separator, and the surface protection film can be suppressed, and the peeling failure of the surface protection film can be suppressed.

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-layered film or a laminate. Specific examples of the single-layer optical film include polarizers and retardation films. Specific examples of the optical film formed in the form of a laminate include a polarizing plate (representing a laminate of a polarizer and a protective film), a conductive film for touch panels, a surface treatment film, and a single layer composed of these according to the purpose. The optical film and/or the optical film constituted in the form of a laminate is appropriately laminated (for example, a circular polarizing plate for anti-reflection, a polarizing plate with a conductive layer for a touch panel).

The adhesive layer 20 can have any suitable structure. Specific examples of the adhesives constituting the adhesive layer include acrylic adhesives, rubber adhesives, silicone adhesives, polyester adhesives, urethane adhesives, epoxy adhesives, and polysilicone 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 crosslinking agent, the reaction temperature, the reaction time, etc., an adhesive with the desired characteristics according to the purpose can be prepared Agent. The base resin of the adhesive may be used alone or in combination of two or more kinds. From the viewpoints of transparency, processability, and durability, it is preferable to use an acrylic adhesive. The details of the adhesive constituting the adhesive layer are described in, for example, Japanese Patent Application Laid-Open No. 2014-115468, and this specification uses the description of the publication as a reference. 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. can be, for example, 1.0×10 ⁴ (Pa) to 1.0×10 ⁶ (Pa). In addition, the storage elastic modulus can be obtained by, for example, dynamic viscoelasticity measurement.

The separating member 30 can be any suitable separating member. Specific examples include plastic film, non-woven fabric, 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 can be, for example, 10 μm-100 μm.

The surface protection film 40 is as described above, and typically has a base material 41 and an adhesive layer 42. The forming material of the base material 41 includes, for example, ester resins such as polyethylene terephthalate resins, cycloolefin resins such as norbornene resins, olefin resins such as polypropylene, polyamide resins, and polycarbonates. Ester resins and other copolymer resins. More desirable is an ester resin (especially a polyethylene terephthalate resin). As long as it is the material, it has the advantage that the modulus of elasticity is high enough and it is not easily deformed even if tension is applied during conveying and/or bonding.

The elastic modulus of the substrate 41 can be, for example, 2.2 kN/mm ² to 4.8 kN/mm ² . As long as the elastic modulus of the substrate is within the above range, it has the advantage that it is not easily deformed even if tension is applied during transportation and/or bonding. In addition, the modulus of elasticity is measured in accordance with JIS K 6781.

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

The adhesive layer (PF adhesive layer) 42 may have any appropriate configuration. 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 forming the adhesive, as well as the blending amount of the crosslinking agent, the reaction temperature, the reaction time, etc., an adhesive with the desired characteristics according to the purpose can be prepared Agent. The base resin of the adhesive may be used alone or in combination of two or more kinds. 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 it is the base resin, a PF adhesive layer with a desired storage elastic modulus can be obtained. The detailed content of the adhesive constituting the PF adhesive layer is described in, for example, Japanese Patent Application Laid-Open No. 2018-123281, and the description in this publication is used for 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. can be, for example, 0.5×10 ⁶ (Pa) to 3.0×10 ⁶ (Pa). As long as the storage elastic modulus is in the above range, an adhesive layer with an excellent balance between adhesiveness and releasability can be obtained (the result is a surface protective film). In addition, the surface protection film can be embossed by the manufacturing method described later. As a result, the embossed part can be used as a gripping edge to easily concentrate stress on the peeling point, so that it can achieve more excellent peeling while maintaining allowable adhesion. Sex.

The thickness of the surface protection film 40 may be 40 μm to 120 μm, for example. In addition, the thickness of the surface protection film refers to the total thickness of the substrate and the 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, the peeling force of the surface protective film) is smaller. In most cases, the peeling force of the surface protection film is greater than the peeling force of the separated parts, and the peeling failure of the surface protection film is likely to occur. However, according to the manufacturing method described later, the peeling failure of the surface protection film can be obtained by cutting. Adhesive layer optical laminate. More specifically, the peeling force of the separator should be 0.001N/10mm~1.0N/10mm, and the peeling force of the surface protective film should be 0.01N/10mm~5.0N/10mm. The peeling force of the separator should be 0.001~0.1N/10mm, more preferably 0.005~0.03N/10mm. The peeling force of the surface protective film should be 0.01~0.5N/10mm, more preferably 0.035~0.1N/10mm. The difference between the peeling force of the separator and the peeling force of the surface protective film (the peeling force of the surface protective film-the peeling force of the separator) should be 0.01N/10mm~1.0N/10mm. According to the manufacturing method described later, even if there is a difference in the peeling force, a cutting-processed optical laminate with an adhesive layer with suppressed peeling defects of the surface protective film can be obtained.

In one embodiment, the thickness of the surface protection film 40 is greater than the thickness of the separator 30. According to the manufacturing method, even when the thickness of the surface protective film is thick and requires a large peeling force, excellent peeling properties can be achieved. The difference between the thickness of the surface protection film and the thickness of the separator (the thickness of the surface protection film-the thickness of the separator) is preferably 5μm~60μm. According to the manufacturing method described later, even if there is a difference in thickness, a cutting-processed optical laminate with an adhesive layer with suppressed peeling defects of the surface protective film can be obtained.

B. Manufacturing method of adhesive layer optical laminate Hereinafter, a representative example of the manufacturing method of the adhesive layer-attached optical laminate will be described. First, the relationship between the structure of the end mill of the characteristic part of the present invention and the layered state of the workpiece will be explained, and then the outline of the manufacturing method will be explained.

B-1. The relationship between the composition of the end mill and the layered state of the workpiece In the embodiment of the present invention, as described above, the adhesive layer optical laminate is superimposed so that the separating member is positioned in the chip discharge direction of the end mill to form a workpiece, and the outer peripheral surface of the workpiece is cut. This will be specifically described with reference to FIGS. 2 and 3. Fig. 2 is a schematic diagram illustrating a representative example of the configuration of an end mill that can be used in the manufacturing method of the present invention. Fig. 3 is a schematic plan view illustrating the difference in the cutting direction between the end mill with the right edge and the left edge. As shown in Figure 2, the structure of the end mill is roughly divided into right-edge right spiral, right-edge left spiral, left-edge right spiral, and left-edge left spiral. As shown in Figure 2, the so-called right edge refers to the structure that can be cut when viewed from the upper side (shank side) when rotating clockwise; the so-called left edge refers to the structure that can be cut when viewed from the upper side (shank side) when rotating counterclockwise The composition. As further shown in Fig. 2, the so-called right spiral refers to the formation of the blade extending diagonally upward to the right when viewed from the side; the so-called left spiral refers to the formation of the blade extending diagonally upward to the left when viewed from the side. The chip discharge direction of the right screw on the right blade and the left screw on the left blade is upward; the chip discharge direction of the left screw on the right blade and the right screw on the left blade is downward. In addition, as shown in Figure 3, the cutting direction of the right blade represents counterclockwise rotation, and the cutting direction of the left blade represents clockwise rotation.

In the embodiment of the present invention, as described above, the adhesive layer optical laminate is superimposed so that the separating member is positioned in the chip discharge direction of the end mill to form a workpiece, and the outer peripheral surface of the workpiece is cut. For example, when the end mill is a right-edge right spiral or a left-edge left spiral, as shown in FIG. 4(a), the adhesive layer optical laminate is laminated so that the separator is located on the upper side to form the workpiece W. On the other hand, when the end mill is a right-edge left-helix or a left-edge right-helix, as shown in Figure 4(b), the adhesive layer optical laminate is laminated so that the separator is located on the lower side. Workpiece W. The inventors found that depending on the relationship between the chip discharge direction of an end mill with a spiral blade and the arrangement of the surface protection film of the optical laminate with the adhesive layer in the workpiece, there may be cases where the surface protection film may be raised or not. There will be embossments; and by making the surface protection film embossed, the problem of poor peeling of the surface protection film can be solved. As long as it is configured as described above, the optical laminate with the adhesive layer will be shaved (or shaved) from the side of the surface protection film to the side of the separator. As a result, a surface protection film that is given a strong cutting force in an oblique direction can be produced. Embossed. Thereby, a cutting-processed optical laminate with an adhesive layer in which peeling defects of the surface protection film are suppressed can be obtained. The relief amount of the surface protection film is preferably 1 μm or 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 embossment is within the above range, it is possible to achieve good peelability of the surface protection film without causing other problems and maintaining the appearance quality within the allowable range. The embossing will reduce the appearance quality, so it will be avoided as much as possible in the industry. However, according to the embodiment of the present invention, by actively making the surface protective film embossed, a technical idea that completely violates the common knowledge of the industry can be obtained A cutting-processed optical laminate with an adhesive layer in which peeling defects are suppressed. In addition, if the relationship between the composition of the end mill and the layered state of the workpiece is reversed (that is, if the end mill is a right-edge right spiral or a left-edge left spiral, the workpiece is formed as shown in Figure 4(b), and the end When the milling cutter is a right-edge left-helix or a left-edge right-helix, the workpiece is formed as shown in Fig. 4(a)), the separation part will produce relief but the surface protection film will not. As a result, the problem of poor peeling of the surface protective film may not be eliminated.

B-2. Form a workpiece Next, the outline of the cutting process will be explained. 5 is a schematic perspective view for explaining the cutting process of the manufacturing method of the present invention, and the workpiece W is shown in this figure. As shown in FIG. 5, a work W is formed by stacking a plurality of optical laminates with adhesive layers. As explained in item B-1, the layered state of the workpiece W is set as shown in Fig. 4(a) or Fig. 4(b) according to the configuration of the end mill. When the optical laminate with an adhesive layer is formed into a workpiece, it means that the upper system is cut into any appropriate shape. Specifically, the adhesive layer optical laminate can be cut into a rectangular shape, can also be cut into a shape similar to a rectangular shape, or can be cut into an appropriate shape (such as a circle) according to the purpose. The workpiece W has outer peripheral surfaces (cutting surfaces) 1a, 1b facing each other, and outer peripheral surfaces (cutting surfaces) 1c, 1d orthogonal to these. The workpiece W is preferably clamped from top to bottom by a clamp mechanism (not shown). The total thickness of the workpiece should be 8mm~20mm, and should be 9mm~15mm, more preferably about 10mm. As long as the thickness is the above-mentioned thickness, it can prevent the clamping mechanism from being damaged by pressing or punching during cutting. The adhesive layer optical layering system is laminated to make the workpiece become the total thickness described. The number of sheets of the adhesive layer optical laminate constituting the workpiece can be, for example, 10 to 50 sheets. The clamping mechanism (such as a clamp) can be composed of soft materials or hard materials. When it is made of soft materials, its hardness (JIS A) should be 60°~80°. If the hardness is too high, there will be residual indentation caused by the clamping mechanism. If the hardness is too low, the position will shift due to the deformation of the fixture, and the cutting accuracy will be insufficient.

B-3. Cutting Next, the end mill 60 is used to cut the outer circumferential surface of the workpiece W. Cutting is typically performed by making the cutting edge of the end mill abut the outer peripheral surface of the workpiece W. Cutting can cover the entire circumference of the outer circumferential surface of the workpiece, or it can be performed only at a predetermined position.

As shown in FIG. 6, the end mill 60 has: a rotating shaft 61 extending in the stacking direction (vertical direction) of the workpiece W; and a cutting edge 62 configured as the outermost outer diameter of the main body rotating around the rotating shaft 61 . In the example of the figure, the cutting edge 62 is configured to be the outermost diameter twisted along the rotating shaft 61, which is shown as a right edge and right spiral. The cutting edge 62 includes a blade 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 example shown in the figure, the cutting edge is composed of three pieces, but the number of edges can be one continuous piece, two pieces, four pieces, or more than five pieces. The edge angle of the end mill (the helix angle θ of the cutting edge in the example of the diagram) should be 20°~60°, and 30°~45° is better. As long as the blade angle is the above-mentioned angle, the surface protection film can be well embossed by cutting. The face behind the cutting edge should be roughened. Any appropriate treatment can be adopted for the roughening treatment. A representative example can be sandblasting. By roughening the flank surface, adhesion of the adhesive to the cutting edge can be suppressed, and as a result, adhesion can be suppressed. The outer diameter of the end mill should be 3mm~20mm. In addition, the term "adhesion" in this specification refers to a phenomenon in which the adhesive layer optical laminates of the workpiece are bonded to each other by the adhesive on the end faces, and the chips of the adhesive attached to the end surfaces promote the adhesion of the adhesive layer optical laminates to each other. In addition, the so-called "outer diameter of the end mill" refers to the value obtained by multiplying the distance from the rotating shaft 61 to the blade 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 one embodiment, the manufacturing method of the present invention includes non-linear cutting of the outer peripheral surface of the workpiece. The non-linear cutting includes, for example, as shown in FIG. 7, a concave portion 4 c including a curved portion formed in a plan view of the adhesive layer optical laminate. To make the optical laminate with an adhesive layer in the top view shape shown in Figure 7, the outer circumference of the workpiece is cut linearly, and chamfered parts 4a and 4b are formed on the two corners of the outer circumference of the workpiece, and the The center part of the outer peripheral surface of the corner|angular part 4a, 4b forms the recessed part (the recessed part containing a curve part) 4c. By forming the concave portion, the surface protection film can be embossed near the concave portion. As a result, the releasability when peeling and removing the surface protective film from the concave portion can be improved. An example of the cutting process will be described with reference to Figs. 8(a) to 8(c). First, as shown in Fig. 8(a), the chamfered portion 4a of Fig. 7 is chamfered, and then, as shown in Fig. 8(b), the chamfered portion 4b is chamfered. Finally, as shown in FIG. 8(c), a concave portion (a concave portion including a curved portion) 4c is formed by cutting. The radius of the curve is preferably 5mm or less, and preferably 4mm or less, more preferably 3mm or less. In addition, the order of forming the chamfered portions 4a and 4b and the recessed portion 4c (cutting order) is not limited, and these can be formed in any appropriate order.

The cutting conditions can be appropriately set according to the desired shape. The rotation number of the end mill should be 1000rpm~60,000rpm, and should be 10000rpm~40,000rpm. The feed speed of the end mill should be 500mm/min~10000mm/min, more preferably 500mm/min~2500mm/min. The number of cuts at the cutting point can be cut once, cut twice, cut 3 times or more.

In the above manner, a cut-processed optical laminate with an adhesive layer can be obtained. In the optical laminate with an adhesive layer obtained by the manufacturing method of the present invention, the peeling failure of the surface protective film is suppressed. Example

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

(1) The incidence of embossment of surface protective film Prepare any number (preferably 100 or more) of optical laminates with adhesive layers after cutting, and use a magnifying glass or microscope to observe the relief of the surface protection film. Observe the entire circumference of each optical laminate with an adhesive layer. If an embossment of 1 μm or more is observed, the optical laminate with an adhesive layer is counted as an embossed sample, and is determined by "( embossed sample/ The number of observations) × 100" to calculate the bump generation rate. (2) Stripping success rate Fifty sheets of the optical laminates with adhesive layers obtained in the examples and comparative examples were randomly selected, and the surface protective films were peeled off for each sheet (initial peeling force 2.9N). The number of times of successful peeling without problems among 50 peelings is expressed as a percentage, and this is taken as the peeling success rate. (3) Amount of relief The amount of relief of the surface protective film in the cut-processed optical laminates with adhesive layers obtained in the examples and comparative examples was measured with a magnifying glass or a microscope. The maximum value of the relief amount of a workpiece is regarded as the relief amount.

>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) )/A polarizing plate with an adhesive layer composed of separate parts. In addition, the surface protection film is a surface protection film with a PET substrate (50μm)/PF adhesive layer (10μm) structure, and it is verified. At this time, the storage elastic modulus of the adhesive layer (adhesive) is adjusted to 0.5MPa~3.0MPa. After punching the polarizer with the adhesive layer obtained in the above manner into a size of 5.7 inches (length 140mm and width 65mm), stack multiple punched polarizers to make a workpiece (total thickness about 10mm). In the state where the obtained workpiece is clamped by a clamp (fixture), the two corners of the outer circumference of the workpiece are processed by an end mill to form a chamfered part, and the chamfered part is formed at the center of the outer peripheral surface. Recesses (including the recesses of the curved portion) to obtain a polarizing plate with an adhesive layer after cutting as shown in FIG. 7. The feed speed of the end mill is 500mm/min~2000mm/min, and the rotation number is 5000rpm~30000rpm. In addition, the end mill uses the right helix and the helix angle of 30°. The chip discharge direction of this end mill is upward. The polarizing plate with the adhesive layer is superimposed so that the separating part is located on the upper side to form a workpiece. The embossing rate of the surface protective film obtained by cutting is 100%. The evaluation of (2) and (3) above was performed on the obtained polarizing plate with an adhesive layer after cutting. The results are listed in Table 1.

>Comparative Example 1> The workpiece was formed by stacking the separator of the polarizing plate with the adhesive layer on the lower side, except that the cutting process was performed in the same manner as in Example 1. The cut-processed polarizing plate with an adhesive layer was used for the same evaluation as in Example 1. The results are listed in Table 1.

>Example 2> The cutting process was performed in the same manner as in Example 1, except that an end mill with a right-edge helix and a helix angle of 45° was used. The cut-processed polarizing plate with an adhesive layer was used for the same evaluation as in Example 1. The results are listed in Table 1.

>Comparative Example 2> The workpiece was formed by superimposing the separator of the polarizing plate with the adhesive layer on the lower side, except that the cutting process was performed in the same manner as in Example 2. The cut-processed polarizing plate with an adhesive layer was used for the same evaluation as in Example 1. The results are listed in Table 1.

[Table 1]

>Evaluation> It can be seen from Table 1 that according to the embodiment of the present invention, by stacking the optical laminate with the adhesive layer so that the separating piece is positioned in the chip discharge direction of the end mill to form a workpiece, the surface protection film can be easily and inexpensively realized. A cut-off optical laminate with an adhesive layer with suppressed peeling defects.

Industrial availability The manufacturing method of the present invention is suitable for manufacturing optical laminates with adhesive layers that require cutting processing (especially non-linear processing). The optical laminate with an adhesive layer 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 100: Optical laminate with adhesive layer 1a, 1b, 1c, 1d: outer peripheral surface (cutting surface) θ: helix angle 4a, 4b: cut corners 4c: Concavity (concavity 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 configuration of an end mill that can be used in the manufacturing method of the present invention. Fig. 3 is a schematic plan view illustrating the difference in the cutting direction between the right edge and the left edge of the end mill applicable to the manufacturing method of the present invention. Fig. 4 (a) is a schematic front view of important parts for explaining a method of forming a workpiece according to an embodiment of the present invention; (b) is a schematic front view of important parts for explaining a method of forming a workpiece according to another embodiment. 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 for explaining the structure of an end mill used for cutting in the manufacturing method of the present invention. FIG. 7 is a schematic plan view showing an example of the shape of an optical laminate with an adhesive layer that can be cut by the manufacturing method of the present invention. 8(a) to (c) are schematic plan 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 (13)

A method for manufacturing a cut-processed optical laminate with an adhesive layer, comprising: Stacking multiple optical laminates with adhesive layers to form a workpiece; and, using an end mill with a spiral blade to cut the outer peripheral surface of the workpiece; The adhesive layer optical laminate includes an optical film, an adhesive layer, a separator, and a surface protection film. The adhesive layer is disposed 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; and In the manufacturing method, the adhesive layer optical laminate is laminated so that the separating piece is positioned in the chip discharge direction of the end mill to form the workpiece. The manufacturing method of claim 1, wherein the aforementioned end mill is a right-edge right spiral or a left-edge left spiral; and In this manufacturing method, the optical laminate with the adhesive layer is laminated so that the separator is located on the upper side to form a workpiece. The manufacturing method of claim 1, wherein the aforementioned end mill is a right-blade left spiral or a left-blade right spiral; and In this manufacturing method, the optical laminate with the adhesive layer is laminated so that the separator is located on the lower side to form a workpiece. The manufacturing method according to any one of claims 1 to 3, wherein the peeling force of the separator and the adhesive layer is smaller than the peeling force of the optical film and the surface protection film. The manufacturing method of claim 4, wherein the peeling force of the separator and the adhesive layer is 0.001N/10mm~1.0N/10mm, and the peeling force of the optical film and the surface protection film is 0.01N/10mm~5.0N /10mm. The manufacturing method according to any one of claims 1 to 5, wherein the thickness of the surface protection film is greater than the thickness of the separator. The manufacturing method according to any one of claims 1 to 6, wherein the surface protective film has a substrate and an adhesive layer, and the storage elastic modulus G'of the adhesive layer at 25° C. is 0.5×10 ⁶ (Pa )~3.0×10 ⁶ (Pa). The manufacturing method according to any one of claims 1 to 7, wherein the surface protection film is embossed by the cutting. The manufacturing method of claim 8, wherein the relief amount of the aforementioned surface protective film is 1 μm to 1000 μm. The manufacturing method according to any one of claims 1 to 9, which includes: non-linear cutting of the outer peripheral surface of the aforementioned workpiece. The manufacturing method of claim 10, wherein the non-linear cutting includes: forming a concave portion including a curved portion when the optical laminate with an adhesive layer is viewed from above. The manufacturing method of claim 11, wherein the radius of the aforementioned curved portion is 5 mm or less. The manufacturing method according to any one of claims 1 to 12, wherein the aforementioned optical film is a polarizer or a polarizing plate.

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