JP7014653B2 - Method for manufacturing a non-linearly processed optical laminate with an adhesive layer - Google Patents

Description

The present invention relates to a method for manufacturing a non-linearly processed optical laminate with an adhesive layer.

Various optical laminates (for example, polarizing plates) are used in image display devices such as mobile phones and notebook personal computers in order to realize image display and / or enhance the performance of the image display. .. In recent years, it has been desired to use an optical laminate for an automobile instrument panel, a smart watch, and the like, and it is desired to process the shape of the optical laminate to a shape other than a rectangle.

Japanese Unexamined Patent Publication No. 2004-114205

The present invention has been made to solve the above-mentioned conventional problems, and a main object thereof is to provide a method capable of easily manufacturing a non-linearly processed optical laminate with an adhesive layer without causing a defect. To do.

The method for manufacturing an optical laminate with an adhesive layer of the present invention is to stack a plurality of optical laminates with an adhesive layer to form a work; a rotation axis perpendicular to the outer peripheral surface of the work and a protrusion toward the cut surface side. While rotating the first cutting means having the cutting blade provided therein, the work and the first cutting means are relatively moved to perform the first cutting in which the outer peripheral surface of the work is linearly cut. That; and while rotating the second cutting means having a rotation axis extending in the stacking direction of the work and a cutting blade configured as the outermost diameter of the main body rotating about the rotation axis, the work and the first. (2) The second cutting is performed by moving the cutting means relatively to cut the outer peripheral surface of the work in a non-linear manner. In this manufacturing method, the first cutting and the second cutting are performed with the work clamped from above and below.
In one embodiment, the first cutting and the second cutting are continuously performed with the work clamped from above and below without opening the clamp.
In one embodiment, the optical laminate is a polarizing plate.
In one embodiment, the length of the portion cut by the second cutting process is 70% or less with respect to the length of the portion cut by the first cutting process and the second cutting process.
In one embodiment, in the manufacturing method, the first cutting is performed after the second cutting.
In one embodiment, the blade angle of the second cutting means is 45 ° to 75 °.
In one embodiment, the diameter of the second cutting means is 3 mm to 20 mm.

According to the method for manufacturing an optical laminate with an adhesive layer of the present invention, a plurality of optical laminates with an adhesive layer are stacked to form a work, the work is linearly cut by double-headed milling, and an end mill is used. By cutting non-linearly by processing, it is possible to easily manufacture an optical laminate with an adhesive layer that has been processed non-linearly without causing any trouble. More details are as follows. When a work is formed by stacking a plurality of optical laminates with an adhesive layer and the work is processed into a shape other than a rectangle, laser processing, punching processing, end mill processing and the like can be mentioned as candidates for the processing method. However, laser processing may adversely affect the optical characteristics of the obtained optical laminate, punching processing may have insufficient shape accuracy, and cracks may occur. Therefore, when an end mill process was attempted, a new problem was discovered in which blocking (specifically, a phenomenon in which optical laminates with an adhesive layer in a work adhere to each other with an adhesive on the end face) occurs. As a result of repeated trial and error on the new problem, the present inventors have discovered that the work end face is coated with an adhesive due to end milling, and the amount of the pressure-sensitive adhesive present on the work end face. It was estimated that blocking could be suppressed by reducing the number, and further trial and error was repeated. As a result, it has been found that by reducing the amount of the adhesive adhering to the cutting blade of the end mill, the amount of the adhesive present on the end face of the work can be reduced and the blocking problem can be solved. Specifically, by performing linear machining (cutting) with double-headed milling and performing only non-linear machining (cutting) with end mill machining, the amount of adhesive adhering to the cutting blade of the end mill is reduced. Solved the blocking problem. That is, the present invention solves a new problem in the technique of non-linear processing of an optical laminate with an adhesive layer.

It is a schematic plan view which shows an example of the shape of the optical laminate with a non-linearly processed pressure-sensitive adhesive layer which can be obtained by the manufacturing method of this invention. It is a schematic perspective view for demonstrating the 1st cutting process in the manufacturing method of this invention. (A)-(e) are schematic plan views explaining a series of procedures of the manufacturing method of this invention. It is a schematic perspective view for demonstrating the 2nd cutting process in the manufacturing method of this invention. It is a schematic diagram for demonstrating an example of the structure of the 2nd cutting means used for the 2nd cutting processing in the manufacturing method of this invention.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. The drawings are schematically shown for easy viewing, and the ratios of length, width, thickness, etc., angles, etc. in the drawings are different from the actual ones.

In the method for manufacturing an optical laminate with an adhesive layer of the present invention, a plurality of optical laminates with an adhesive layer are stacked to form a work; the first cutting for linearly cutting the outer peripheral surface of the work is performed; It also includes performing a second cutting that cuts the outer peripheral surface of the work in a non-linear manner. Examples of the optical laminate with an adhesive layer include any suitable optical laminate with an adhesive layer that can be used in applications that require non-linear processing. Specific examples of the optical laminate with the pressure-sensitive adhesive layer include a polarizing plate, a retardation plate, a conductive film for a touch panel, a surface-treated film, and a laminate appropriately laminated according to the purpose (for example, for antireflection). Circular polarizing plate, polarizing plate with conductive layer for touch panel) can be mentioned. The effect of the present invention becomes remarkable in the non-linear processing of the optical laminate with the pressure-sensitive adhesive layer. Hereinafter, as an example, each step in the method for manufacturing a planar optical laminate with an adhesive layer as shown in FIG. 1 will be described.

A. Forming of Work FIG. 2 is a schematic perspective view for explaining the first cutting process, and the work 1 is shown in this figure. As shown in FIG. 2, a work 1 in which a plurality of optical laminates are stacked is formed. The optical laminate with the pressure-sensitive adhesive layer is typically cut into an arbitrary appropriate shape when the work is formed. Specifically, the optical laminate with the pressure-sensitive adhesive layer may be cut into a rectangular shape, or may be cut into a shape similar to the rectangular shape. In the illustrated example, the optical laminate with the pressure-sensitive adhesive layer is cut into a rectangular shape, and the work 1 has outer peripheral surfaces (cutting surfaces) 1a and 1b facing each other and outer peripheral surfaces (cutting surfaces) 1c and 1d orthogonal to them. have. The work 1 is preferably clamped from above and below by clamping means (not shown). The total thickness of the work is preferably 10 mm or more, more preferably 15 mm or more, still more preferably 20 mm or more. The upper limit of the total thickness of the work is, for example, 150 mm. With such a thickness, it is possible to prevent damage due to pressing by the clamping means or impact during cutting. The optical laminate with the pressure-sensitive adhesive layer is laminated so that the workpieces have such a total thickness. The number of optical laminates with an adhesive layer constituting the work is 10 or more in one embodiment, and 30 to 50 in one embodiment. The clamping means (for example, a jig) may be made of a soft material or a hard material. When composed of a soft material, its hardness (JIS A) is preferably 60 ° to 80 °. If the hardness is too high, imprints may remain due to the clamping means. If the hardness is too low, the jig may be deformed and misaligned, resulting in insufficient cutting accuracy.

B. First cutting process The outer peripheral surface of the work 1 formed as described above (the cut surface of the optical laminate with the adhesive layer) is linearly cut by the first cutting means 2. The first cutting process is a so-called double-headed milling process. Specifically, the first cutting means 2 has a rotary plate 3 and a cutting blade 4, has a rotary shaft S perpendicular to the outer peripheral surfaces 1a and 1b, and has a rotary shaft S by an arbitrary appropriate drive mechanism. It is configured to be rotatable in the R direction as the center. The rotary plate 3 is arranged in parallel with the outer peripheral surfaces 1a and 1b of the work 1, has a circular shape in a side view, and is designed so that its diameter exceeds the thickness h of the work 1. The cutting blades 4 are provided so as to project in the axial direction of the rotating shaft S, and are arranged at predetermined intervals on the flat surface portion of the rotating plate 3. In the illustrated example, the pair of first cutting means 2 are provided with a predetermined interval D so that the flat surface portions having the cutting blades 4 face each other, so that the respective cutting blades 4 are arranged so as to correspond to the outer peripheral surfaces 1a and 1b. Has been done. The distance D between the cutting means 2 is set so that the work 1 can be carried in and the cutting blade 4 cuts a predetermined cutting allowance. The pair of first cutting means 2 is configured to be movable in the rotation axis S direction so that the distance D can be changed.

The work 1 is movable in a direction orthogonal to the rotation axis S (direction of arrow A in FIG. 2), and is mounted on a mounting table configured to be rotatable in the moving surface. As shown in FIGS. 2 and 3A, the mounting table is moved in the A direction to cut the outer peripheral surfaces 1a and 1b. Next, the distance D of the first cutting means 2 is changed so as to correspond to the outer peripheral surfaces 1c and 1d, and the mounting table is rotated by 90 °. As shown in FIG. 3B, in this state, the mounting table is moved in the A direction to cut the outer peripheral surfaces 1c and 1d. In this way, cutting (straight cutting) of all outer peripheral surfaces of the work is completed. In the illustrated example, the work is moved in the direction of arrow A, but the first cutting means may be moved in the direction opposite to the direction of A, and the work may be moved in the direction of A and the first cutting means may be moved in the direction of A. You may move it in the opposite direction.

The details of the first cutting process (double-headed milling process) are described in, for example, Japanese Patent Application Laid-Open No. 2005-224935 and Japanese Patent Application Laid-Open No. 2007-22231, and the description of the relevant publications is referred to in the present specification. It will be used.

C. Second cutting process Next, a predetermined position on the outer peripheral surface of the work 1 is cut non-linearly by the second cutting means 20. When an optical laminate with an adhesive layer having a plan view shape as shown in FIG. 1 is produced, chamfered portions 4a and 4b are formed at two corners of the outer periphery of the work, and chamfered portions 4a and 4b are formed. A recess 4c is formed in the central portion of the outer peripheral surface. As shown in FIG. 4, the second cutting process is a so-called end mill process. That is, the side surface of the second cutting means (end mill) 20 is used to cut a predetermined position on the outer peripheral surface of the work 1 in a non-linear manner. As the second cutting means (end mill) 20, a straight end mill can be typically used.

Specifically, as shown in FIG. 5, the second cutting means 20 is configured as a rotating shaft 21 extending in the stacking direction (vertical direction) of the work 1 and an outermost diameter of a main body rotating about the rotating shaft 21. It has a cutting blade 22 to be formed. In the illustrated example, the cutting blade 22 is configured as the outermost diameter twisted along the rotating shaft 21. The cutting blade 22 includes a cutting edge 22a, a rake surface 22b, and a relief surface 22c. The number of cutting blades 22 can be appropriately set according to the purpose. The cutting blade in the illustrated example has a configuration of three blades, but the number of blades may be one continuous blade, two blades, four blades, or five or more blades. good. The blade angle of the second cutting means (twist angle θ of the cutting blade in the illustrated example) is preferably 45 ° to 75 °, more preferably 45 ° to 60 °. With such a blade angle, the shavings of the adhesive can be easily discharged from the cutting blade, and as a result, blocking can be suppressed. The relief surface of the cutting blade is preferably roughened. As the roughening process, any appropriate process can be adopted. A typical example is blasting. By applying the roughening treatment to the relief surface, the adhesion of the adhesive to the cutting blade can be suppressed, and as a result, blocking can be suppressed. By appropriately combining the roughening treatment of the relief surface and the adjustment of the blade angle, blocking can be further suppressed by the above synergistic effect.

The work 1 that has been first cut as described in item B is cut non-linearly by the second cutting means (end mill) 20. First, as shown in FIG. 3 (c), the portion where the chamfered portion 4a of FIG. 1 is formed is chamfered, and then, as shown in FIG. 3 (d), the portion where the chamfered portion 4b is formed is chamfered. It will be processed. Finally, as shown in FIG. 3 (e), the recess 4c is formed by cutting. The conditions for the second cutting process can be appropriately set according to the desired shape. For example, the diameter of the second cutting means (end mill) 20 is preferably 3 mm to 20 mm. The rotation speed of the second cutting means is preferably 1000 rpm to 60,000 rpm, more preferably 10,000 rpm to 40,000 rpm. The feed rate of the second cutting means is preferably 500 mm / min to 10000 mm / min, and more preferably 500 mm / min to 2500 mm / min. The number of cuts at the cutting location can be one cut, two cuts, three cuts or more. In the illustrated example, the chamfered portion 4a, the chamfered portion 4b, and the recess 4c are formed in this order, but these may be formed in any appropriate order.

The length of the portion cut in the second cutting process (that is, the length of the portion cut in a non-linear manner) is the length of the portion cut in the first cutting process and the second cutting process (that is, cutting). It is preferably 70% or less with respect to the length of the entire portion).

The first cutting process and the second cutting process are preferably performed continuously. More specifically, the first cutting process and the second cutting process are performed with the work 1 clamped from above and below without opening the clamp. By performing the first cutting and the second cutting continuously without opening the clamp (that is, the work of changing the work from the first cutting means to the second cutting means is omitted, the work efficiency is improved. be able to. Here, in such continuous machining, the entire circumference is machined while the work is fixed, so that a blocking problem is likely to occur. However, according to the embodiment of the present invention, by performing only non-linear machining (cutting) by end mill machining, it is possible to reduce the area of end mill machining where blocking is more likely to occur, and the clamp can be opened. It is possible to suppress the occurrence of blocking even if the first cutting process and the second cutting process are continuously performed. That is, according to the embodiment of the present invention, it is possible to significantly improve the work efficiency while satisfactorily suppressing blocking.

As described above, an optical laminate with a non-linearly processed pressure-sensitive adhesive layer can be obtained. In the illustrated example, the mode in which the first cutting process (straight line processing) and the second cutting process (non-linear processing) are performed in this order has been described, but the order of the first cutting process and the second cutting process is reversed. May be good. According to the mode in which the second cutting process (non-linear processing) and the first cutting process (straight line processing) are performed in this order, the blocking caused by the non-linear processing can be eliminated by the vibration of the work during the linear processing. In some cases.

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

(1) Blocking The state of the workpiece after cutting in the examples and comparative examples was observed and evaluated according to the following criteria.
◯: It was easy to separate the work from the individual optical laminates Δ: It was possible to separate the work from the individual optical laminates, but the separation operation was difficult ×: The work was completely block-shaped (2) Blade dirt The state of contamination by the adhesive of the second cutting means (end mill) after cutting in the examples and comparative examples was observed. , Evaluated according to the following criteria.
○: Substantially no contamination was observed △: Contamination was observed, but no problem occurred in processing. ×: Significant contamination was observed, and there was a problem in processing.

<Reference example 1: Fabrication of work>
As a substituent, a film (thickness 28 μm) obtained by containing iodine in a long polyvinyl alcohol (PVA) -based resin film and uniaxially stretching it in the longitudinal direction (MD direction) was used. A pressure-sensitive adhesive layer (thickness 5 μm) was formed on one side of the polarizing element, and long HC-TACs were bonded together via the pressure-sensitive adhesive layer so as to align their longitudinal directions with each other. The HC-TAC film is a film in which a hard coat (HC) layer (2 μm) is formed on a triacetyl cellulose (TAC) film (25 μm), and the TAC film is bonded so as to be on the substituent side. .. Adhesive layers are formed on both sides of the obtained laminate of the polarizing element / TAC film / HC layer, and a separator is attached to each of the adhesive layers to form an optical laminate with a long adhesive layer (adhesive layer). A polarizing plate) was obtained.
The obtained polarizing plate with an adhesive layer was punched out to a size of 5.7 inches (length 140 mm and width 65 mm), and 40 punched polarizing plates were stacked to form a work.

<Example 1>
With the work obtained in Reference Example 1 sandwiched between clamps (jigs), chamfered portions are formed at the two corners of the outer periphery of the work by end milling, and the central portion of the outer peripheral surface on which the chamfered portions are formed. A recess was formed in.
Next, a double-headed milling cutter as shown in FIG. 2 was used to linearly cut the outer peripheral surface of the work to obtain a non-linearly processed polarizing plate with an adhesive layer as shown in FIG.
Here, the number of blades of the end mill was two, and the blade angle (twist angle) was 45 °. The feed rate of the end mill was 1400 mm / min, and the rotation speed was 30,000 rpm.
The state of the work after processing and the blade stain of the end mill were evaluated as described in (1) and (2) above. The results are shown in Table 1.

<Example 2>
A polarizing plate with an adhesive layer processed in a non-linear manner as shown in FIG. 1 was obtained in the same manner as in Example 1 except that the blade angle of the end mill was 60 °. The state of the work after processing and the dirt on the blade of the end mill were evaluated in the same manner as in Example 1. The results are shown in Table 1.

<Example 3>
A polarizing plate with an adhesive layer processed in a non-linear manner as shown in FIG. 1 was obtained in the same manner as in Example 1 except that the blade angle of the end mill was 20 °. The state of the work after processing and the dirt on the blade of the end mill were evaluated in the same manner as in Example 1. The results are shown in Table 1.

<Example 4>
A polarizing plate with a non-linearly processed adhesive layer was obtained in the same manner as in Example 1 except that the order of double-headed milling and end milling was changed. The state of the work after processing and the dirt on the blade of the end mill were evaluated in the same manner as in Example 1. The results are shown in Table 1.

<Comparative Example 1>
A polarizing plate with an adhesive layer processed in a non-linear manner as shown in FIG. 1 was obtained only by end mill processing. The state of the work after processing and the dirt on the blade of the end mill were evaluated in the same manner as in Example 1. The results are shown in Table 1. In this comparative example, work blocking was remarkable. Furthermore, the adhesive adhered severely to the cutting blade of the end mill, and the end mill had to be carefully cleaned for each work.

<Comparative Example 2>
By punching using a Thomson blade, a non-linearly processed polarizing plate with an adhesive layer as shown in FIG. 1 was obtained. The state of the work after processing and the blade stain of the Thomson blade were evaluated in the same manner as in Example 1. The results are shown in Table 1. In this comparative example, cracks of about 200 μm occurred in the obtained polarizing plate (particularly in the recesses).

<Comparative Example 3>
Cutting was performed using a CO ₂ laser (wavelength: 9.35 μm, output: 150 W) to obtain a non-linearly processed polarizing plate with an adhesive layer as shown in FIG. The state of the work after processing was evaluated in the same manner as in Example 1. The results are shown in Table 1. In this comparative example, a polarization elimination region was observed near the cutting portion.

The production method of the present invention can be suitably used for producing an optical laminate with an adhesive layer that requires non-linear processing. The optical laminate with an adhesive layer obtained by the production method of the present invention can be suitably used for an image display unit having a deformed shape represented by an instrument panel of an automobile or a smart watch.

1 Work 2 1st cutting means 20 2nd cutting means

Claims (6)

Forming a work by stacking multiple optical laminates with an adhesive layer,
While rotating the first cutting means having a rotation axis perpendicular to the cutting surface of the outer peripheral surface of the work and a cutting blade provided so as to project toward the cutting surface side, the work and the first cutting means are relatively moved. It was configured to perform the first cutting that linearly cuts the outer peripheral surface of the work by moving it, and as the outermost diameter of the rotation axis extending in the stacking direction of the work and the main body rotating around the rotation axis. While rotating the second cutting means having the cutting blade, the work and the second cutting means are relatively moved to perform the second cutting in which the outer peripheral surface of the work is cut non-linearly.
Including
With the work clamped from above and below , the first cutting and the second cutting are continuously performed without opening the clamp .
A method for manufacturing an optical laminate with an adhesive layer that has been processed in a non-linear manner. The manufacturing method according to claim 1 , wherein the optical laminate is a polarizing plate. The first or second claim, wherein the length of the portion cut by the second cutting process is 70% or less with respect to the length of the portion cut by the first cutting process and the second cutting process. Manufacturing method. The manufacturing method according to any one of claims 1 to 3 , wherein the first cutting is performed after the second cutting. The manufacturing method according to any one of claims 1 to 4 , wherein the blade angle of the second cutting means is 45 ° to 75 °. The manufacturing method according to any one of claims 1 to 5 , wherein the diameter of the second cutting means is 3 mm to 20 mm.

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