WO2019198617A1 - Method for manufacturing machined optical laminate with hard coat layer - Google Patents

Abstract

The present invention provides a method for simply manufacturing a machined optical laminate with a hard coat layer without causing a problem while minimizing cracks in the hard coat layer. The method for manufacturing a machined optical laminate with a hard coat layer according to the present invention includes: forming a workpiece by laminating a plurality of optical laminates with hard coat layers; and machining the outer peripheral surface of the workpiece with the cutting blade of a cutting means brought into contact with the outer peripheral surface of the workpiece, the cutting means having a rotary shaft extending in the laminate direction of the workpiece and a cutting blade configured as the outermost diameter of a body rotating about the rotary shaft. The optical laminate with a hard coat layer comprises an optical film, a hard coat layer, an adhesive layer, and a separator in this order. A storage elastic modulus G' at 25°C in the adhesive layer is 1.0 × 105 (Pa) to 2.5 × 105 (Pa), and the thickness of the adhesive layer is 50 µm or greater.

Description

Manufacturing method of cut optical laminate with hard coat layer

The present invention relates to a method for producing a cut optical layered body with a coated 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 automobile instrument panels, smart watches, and the like, and it is desired to process the optical laminate into a desired shape. Furthermore, there are cases where the optical laminate includes a hard coat layer, and when processing an optical laminate including such a hard coat layer, there is a problem that cracks are likely to occur in the hard coat layer. In particular, when processing other than a rectangle (deformation processing, non-linear processing), cracks generated in the hard coat layer become prominent.

JP 2004-114205 A

The present invention has been made in order to solve the above-described conventional problems, and its main purpose is to suppress the crack of the hard coat layer and to produce an optical laminate with a hard coat layer that has been machined without causing defects. It is to provide a method that can be easily produced.

The method for producing a cut optical laminate with a hard coat layer according to the present invention includes forming a workpiece by stacking a plurality of optical laminates with a hard coat layer; and a rotating shaft extending in the stacking direction of the workpiece; Cutting the outer peripheral surface of the workpiece by bringing the cutting blade of a cutting means having a cutting blade configured as the outermost diameter of the main body rotating about the rotation axis into contact with the outer peripheral surface of the workpiece; Including. The optical laminate with a hard coat layer includes an optical film, a hard coat layer, a pressure-sensitive adhesive layer, and a separator in this order, and the storage elastic modulus G ′ at 25 ° C. of the pressure-sensitive adhesive layer is 1.0 ×. 10 ⁵ (Pa) to 2.5 × 10 ⁵ (Pa), and the thickness of the pressure-sensitive adhesive layer is 50 μm or more.
In one embodiment, the manufacturing method includes cutting the outer peripheral surface of the workpiece non-linearly.
In one embodiment, the cutting means is an end mill.
In one embodiment, the optical film is a polarizer or a polarizing plate.
In one embodiment, the optical layered body with a hard coat layer further includes an optical functional film between the polarizer or the polarizing plate and the hard coat layer.
In one embodiment, the optical functional film includes at least one selected from a cellulose resin, a cycloolefin resin, and an acrylic resin.
In one embodiment, the breaking strength of the optical function film is 35 N or less.
In one embodiment, the cutting means includes a rotating shaft extending in the stacking direction of the workpieces and the cutting blade configured as an outermost diameter twisted along the rotating shaft.
In one embodiment, the non-linear cutting includes forming a concave portion including a curved portion when the optical layered body with a hard coat layer is viewed in plan.
In one embodiment, the radius of the above-mentioned curve part is 5 mm or less.

According to the present invention, a work is formed by stacking a plurality of optical laminates with a hard coat layer, and is configured as a rotation axis extending in the lamination direction of the work and an outermost diameter of a main body that rotates around the rotation axis. In a method for manufacturing an optical laminate with a hard coat layer, the method comprising: bringing a cutting blade of a cutting means having a cutting blade into contact with the outer peripheral surface of the workpiece and cutting the outer peripheral surface of the workpiece; and adjacent to the hard coat layer By making the storage elastic modulus of the pressure-sensitive adhesive layer to be in a predetermined range and the thickness to be a predetermined value or more, cracks in the hard coat layer are suppressed, and a hard coat layer-attached optical laminate that has been cut without causing defects The body can be easily produced. Such an effect is particularly remarkable when the outer peripheral surface of the workpiece is processed non-linearly. More details are as follows. When a workpiece is formed by stacking a plurality of optical laminates with hard coat layers and the workpiece is processed into a desired shape (for example, a shape other than a rectangle), the processing methods include laser processing, punching processing, and cutting blade. A candidate is a processing method (for example, end mill processing) in which the surface is brought into contact with the cutting surface from the lateral direction. However, laser processing may adversely affect the optical properties of the resulting optical laminate, and punching has insufficient shape accuracy. Then, when end mill processing was attempted, a problem that cracks occurred in the hard coat layer was newly discovered. As a result of repeating trial and error for the new problem, the inventors set the storage elastic modulus of the pressure-sensitive adhesive layer adjacent to the hard coat layer in the optical laminate with a hard coat layer to a predetermined range, and the thickness to a predetermined value. By setting it as the above, it discovered that the said adhesive layer absorbed the damage to the hard-coat layer by a cutting means, and can suppress a crack. That is, this invention solves the problem which arose newly in the technique of cutting an optical laminated body with a hard-coat layer.

It is a schematic sectional drawing explaining an example of the optical laminated body with a hard-coat layer which can be used for the manufacturing method of this invention. It is a schematic sectional drawing explaining another example of the optical laminated body with a hard-coat layer which can be used for the manufacturing method of this invention. It is a schematic plan view which shows an example of the shape of the optical laminated body with a hard coat layer by which the cutting process which can be obtained by the manufacturing method of this invention was carried out. It is a schematic perspective view for demonstrating the cutting process in the manufacturing method of this invention. It is the schematic for demonstrating the structure of the cutting means used for the cutting in the manufacturing method of this invention. (A)-(c) is a schematic plan view explaining the series of procedures of the cutting process 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. Note that the drawings are schematically shown for ease of viewing, and the ratios of length, width, thickness, etc., angles, and the like in the drawings are different from actual ones.

The method for producing an optical laminate with a hard coat layer according to the present invention includes forming a workpiece by stacking a plurality of optical laminates with a hard coat layer; and a rotation axis extending in the lamination direction of the workpiece and the rotation axis as a center. Cutting the outer peripheral surface of the workpiece by bringing the cutting blade of the cutting means having a cutting blade configured as the outermost diameter of the rotating main body into contact with the outer peripheral surface of the workpiece. In particular, the effect of the present invention is remarkable in non-linear processing (deformation processing) of an optical laminate with a hard coat layer.

A. FIG. 1 is a schematic cross-sectional view for explaining an example of an optical laminate with a hard coat layer that can be used in the production method of the present invention. The optical laminated body 100 with a hard-coat layer of the example of illustration contains the optical film 110, the hard-coat layer 120, the adhesive layer 130, and the separator 140 in this order. When the optical laminate with a hard coat layer is applied to an image display device, typically, the separator 140 is disposed on the viewing side. In actual use of the optical laminate with a hard coat layer, the separator 140 is peeled and removed, and a cover glass or the like is bonded to the pressure-sensitive adhesive layer 130. Practically, the optical laminate with a hard coat layer 100 may further include another pressure-sensitive adhesive layer 150 and another separator 160 on the opposite side of the optical film 110 from the hard coat layer 120. Another pressure-sensitive adhesive layer 150 can be used for bonding the optical laminate with a hard coat layer to an image display device (substantially a display cell).

FIG. 2 is a schematic cross-sectional view illustrating another example of an optical laminate with a hard coat layer that can be used in the production method of the present invention. The optical layered body 101 with a hard coat layer in the illustrated example further includes an optical functional film 170 between the optical film 110 and the hard coat layer 120.

Any appropriate surface treatment layer is provided between the optical film 110 or the optical functional film 170 and the hard coat layer 120 and / or between the hard coat layer 120 and the pressure-sensitive adhesive layer 130 depending on the purpose. May be. Examples of the surface treatment layer include an antireflection layer, an antiglare layer, and an antiglare layer.

Hereinafter, specific configurations of the optical film 110, the hard coat layer 120, the pressure-sensitive adhesive layer 130, and the optical functional film 170 will be briefly described.

Examples of the optical film 110 include any appropriate optical film that can be laminated with a hard coat layer and can be used for applications that require cutting (particularly non-linear processing). The optical film may be a film composed of a single layer or a laminate. Specific examples of the optical film composed of a single layer include a polarizer and a retardation film. Specific examples of the optical film configured as a laminate include a polarizing plate (typically, a laminate of a polarizer and a protective film), a conductive film for a touch panel, a surface treatment film, and a single layer thereof. Examples include a laminated body (for example, a circularly polarizing plate for antireflection, a polarizing plate with a conductive layer for touch panel) obtained by appropriately laminating an optical film constituted and / or an optical film constituted as a laminated body according to the purpose.

The hard coat layer 120 preferably has sufficient surface hardness, excellent mechanical strength, and excellent light transmittance. The hard coat layer may be formed from any appropriate resin as long as it has such desired properties. Specific examples of the resin include a thermosetting resin, a thermoplastic resin, an ultraviolet curable resin, an electron beam curable resin, and a two-component mixed resin. An ultraviolet curable resin is preferred. This is because the hard coat layer can be formed with a simple operation and high efficiency. Specific examples of the ultraviolet curable resin include polyester, acrylic, urethane, amide, silicone, and epoxy ultraviolet curable resins. The ultraviolet curable resin includes an ultraviolet curable monomer, oligomer, and polymer. A preferable ultraviolet curable resin includes a resin composition containing an acrylic monomer component or oligomer component having preferably two or more, more preferably 3 to 6, ultraviolet polymerizable functional groups. Typically, a photopolymerization initiator is blended in the ultraviolet curable resin. The hard coat layer can be formed by any appropriate method. For example, the hard coat layer can be formed by applying a resin composition for forming a hard coat layer on a substrate, drying it, and irradiating the dried coating film with ultraviolet rays to cure it. The hard coat layer formed on the substrate can be transferred to an optical film or an optical functional film. The hard coat layer may be directly applied to the optical film or the optical functional film.

The thickness of the hard coat layer is, for example, 0.5 μm to 20 μm, preferably 1 μm to 15 μm.

The hard coat layer preferably has a pencil hardness of H or higher, more preferably 2H or higher, and even more preferably 3H or higher. The pencil hardness can be measured according to, for example, JIS K 5600.

In the embodiment of the present invention, the storage elastic modulus G ′ at 25 ° C. of the pressure-sensitive adhesive layer 130 is 1.0 × 10 ⁵ (Pa) to 2.5 × 10 ⁵ (Pa), and the pressure-sensitive adhesive layer The thickness is 50 μm or more. By optimizing the storage elastic modulus and thickness of the pressure-sensitive adhesive layer 130 adjacent to the hard coat layer 120, the pressure-sensitive adhesive layer is cut in the cutting process (particularly non-linear processing) of the optical layered body with a hard coat layer. Since damage to the hard coat layer by the means can be satisfactorily absorbed, the occurrence of cracks in the hard coat layer can be remarkably suppressed. The storage elastic modulus of the pressure-sensitive adhesive layer 130 is preferably 1.1 × 10 ⁵ (Pa) to 2.3 × 10 ⁵ (Pa), more preferably 1.2 × 10 ⁵ (Pa) to 2.0. × 10 ⁵ (Pa). The storage elastic modulus can be obtained from, for example, dynamic viscoelasticity measurement.

The thickness of the pressure-sensitive adhesive layer 130 is preferably 70 μm to 250 μm, more preferably 80 μm to 200 μm, and still more preferably 100 μm to 150 μm.

As the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 130, any appropriate pressure-sensitive adhesive can be adopted as long as it has pressure-sensitive adhesiveness and transparency that can be used for optical applications and has the desired storage elastic modulus. it can. Specific examples include acrylic adhesives, rubber adhesives, silicone adhesives, polyester adhesives, urethane adhesives, epoxy adhesives, and polyether adhesives. By adjusting the type, number, combination and blending ratio of the monomers forming the base resin of the pressure-sensitive adhesive, the amount of the crosslinking agent, the reaction temperature, the reaction time, etc., the pressure-sensitive adhesive having the desired storage elastic modulus is obtained. Can be prepared. The base resin of the pressure-sensitive adhesive may be used alone or in combination of two or more. From the viewpoints of transparency, processability and durability, an acrylic pressure-sensitive adhesive is preferred. Details of the pressure-sensitive adhesive are described in, for example, Japanese Patent Application Laid-Open No. 2014-115468, and the description of the publication is incorporated herein by reference. In addition, as an adhesive which comprises another adhesive layer 150, a well-known and usual adhesive can be used in the industry.

The optical functional film 170 is a component provided as necessary. The optical functional film is provided for imparting a desired optical function according to the purpose to the optical laminate with a hard coat layer. Examples of the optical functional film include a polarizer or polarizing plate protective film, an antireflection film, an antiglare film, and a film for improving visibility when viewed through a polarized sunglasses. As a film for improving the visibility when viewed through polarized sunglasses, for example, a film having an (elliptical) circular polarization function (for example, λ / 4 plate), an ultrahigh retardation film (for example, 2000 nm or more) Film having in-plane retardation).

In one embodiment, the optical functional film 170 may be formed of a resin film. Examples of the resin constituting the resin film include a cellulose resin, a cycloolefin resin, and an acrylic resin. These may be used alone or in combination.

The breaking strength of the optical functional film 170 is preferably 35 N or less, more preferably 5 N to 30 N, and even more preferably 7 N to 28 N. According to the embodiment of the present invention, cracks can be satisfactorily suppressed even when an optical functional film having such a low breaking strength is used. The breaking strength can be typically measured according to JIS K 7161.

The above embodiments can be appropriately combined. Therefore, it should be understood that this specification describes all combinations of the optical film, the hard coat layer, the pressure-sensitive adhesive layer, and the optical functional film (when present). It is obvious to those skilled in the art that the present invention can be applied to any combination of these.

Hereafter, each process in the manufacturing method of the optical laminated body with a hard-coat layer of a planar shape as shown in FIG. 3 as an example is demonstrated.

B. Formation of Workpiece FIG. 4 is a schematic perspective view for explaining the cutting process, and the work 1 is shown in this drawing. As shown in FIG. 4, a work 1 is formed by stacking a plurality of optical laminates with hard coat layers. The optical layered body with a hard coat layer is typically cut into any appropriate shape when forming a workpiece. Specifically, the optical laminate with a hard coat layer may be cut into a rectangular shape, may be cut into a shape similar to the rectangular shape, and has an appropriate shape (for example, a circle) according to the purpose. It may be cut. The workpiece 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. The workpiece 1 is preferably clamped from above and below by clamping means (not shown). The total thickness of the workpiece is preferably 8 mm to 20 mm, more preferably 9 mm to 15 mm, and even more preferably about 10 mm. If it is such thickness, the damage by the impact at the time of the press by a clamp means or a cutting process can be prevented. The optical laminate with a hard coat layer is overlaid so that the workpiece has such a total thickness. The number of the optical laminate with a hard coat layer constituting the work may be, for example, 10 to 50. The clamp 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, there may be a case where a mark is left by the clamping means. If the hardness is too low, displacement may occur due to deformation of the jig and cutting accuracy may be insufficient.

C. Next, the outer peripheral surface of the workpiece 1 is cut by the cutting means 20. Cutting is performed by bringing the cutting blade of the cutting means into contact with the outer peripheral surface of the workpiece 1 as described above. Cutting may be performed over the entire circumference of the outer peripheral surface of the workpiece, or may be performed only at a predetermined position. In the following illustrated example, cutting is performed over the entire circumference of the outer peripheral surface of the workpiece. When producing an optical laminate with a hard coat layer having a planar view shape as shown in FIG. 3, the outer periphery of the workpiece is cut linearly, and chamfered portions 4a and 4b are formed at two corners of the outer periphery of the workpiece. Then, a concave portion (a concave portion including a curved portion) 4c is formed in the central portion of the outer peripheral surface where the chamfered portions 4a and 4b are formed. The cutting is typically so-called end milling as shown in FIGS. That is, the outer peripheral surface of the workpiece 1 is cut using the side surface of the cutting means (end mill) 20. As the cutting means (end mill) 20, a straight end mill can be typically used.

Specifically, as shown in FIG. 5, the cutting means 20 is configured as a rotating shaft 21 extending in the stacking direction (vertical direction) of the workpiece 1 and an outermost diameter of a main body that rotates around the rotating shaft 21. A cutting blade 22. In the illustrated example, the cutting blade 22 is configured as an outermost diameter twisted along the rotation shaft 21. The cutting blade 22 includes a cutting edge 22a, a rake surface 22b, and a relief surface 22c. The number of blades of the cutting blade 22 can be appropriately set according to the purpose. Although the cutting blade in the illustrated example has a configuration of three sheets, the number of blades may be one continuous, two, four, or five or more. Good. Preferably, the number of blades is 3 or more. If the number of blades is three or more, the adhesion of the shaving residue of the adhesive to the escape surface 22c is suppressed, and as a result, blocking can be suppressed. This is a tendency opposite to that of cutting of an optical laminate including a normal pressure-sensitive adhesive layer. That is, in the cutting of an optical laminated body including a normal pressure-sensitive adhesive layer, if the number of blades is large, the scraps accumulate on the rake face 22b and often cause cutting defects. On the other hand, when the optical laminate with a hard coat layer includes a soft adhesive layer as in the present invention, the elastic recovery of the optical laminate with a hard coat layer (its adhesive layer) is suppressed when the number of blades is large. Adhesion of the adhesive scraps to the escape surface 22c is suppressed. As a result, contact between the scraped residue of the pressure-sensitive adhesive and the optical laminate with a hard coat layer (adhesive layer thereof) is suppressed, and as a result, blocking due to the scraped residue can be suppressed. More specifically, it is as follows: In general, the smaller the number of blades, the better the scraping performance of the adhesive scrap on the rake face, while the greater the cutting resistance per blade, Since the elastic recovery of the pressure-sensitive adhesive layer is increased, the shavings of the pressure-sensitive adhesive easily adhere to the escape surface. In the cutting of an optical layered body including a normal pressure-sensitive adhesive layer, the influence of the scraping property of the pressure-sensitive adhesive on the rake face is larger, so that blocking with a smaller number of blades can suppress blocking. On the other hand, when the optical layered body with a hard coat layer includes a soft pressure-sensitive adhesive layer as in the present invention, the effect of elastic recovery of the pressure-sensitive adhesive layer is larger, so that the one with a larger number of blades can suppress blocking. In the present specification, “blocking” refers to a phenomenon in which the optical laminates with hard coat layers in the work are bonded to each other with the pressure-sensitive adhesive on the end surface. It will contribute to the adhesion between the bodies. The blade angle of the cutting means (the 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 shaving residue 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. Any appropriate process can be adopted as the roughening process. A typical example is blasting. By applying a roughening treatment to the relief surface, adhesion of the adhesive to the cutting blade is suppressed, and as a result, blocking can be suppressed. By appropriately combining the number of blades, the roughening treatment of the relief surface, and the adjustment of the blade angle, blocking can be further suppressed by the above synergistic effect. That is, if an end mill is the above structures, blocking can be suppressed favorably.

An example of cutting (non-linear machining) of the workpiece 1 will be described. First, as shown in FIG. 6A, the portion where the chamfered portion 4a in FIG. 3 is formed is chamfered, and then, as shown in FIG. 6B, the portion where the chamfered portion 4b is formed is chamfered. Processed. Finally, as shown in FIG. 6C, 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 further preferably 3 mm or less. According to the embodiment of the present invention, cracks can be satisfactorily suppressed even when such a curved portion having a small radius is formed. In addition, the formation order (cutting order) of the chamfered parts 4a and 4b and the recessed part 4c is not limited. Further, the non-linear machining as described above may be performed continuously with the linear machining (for example, unlike the illustrated example, the entire circumference of the workpiece may be continuously machined), and a predetermined linear machining is performed. You may carry out after performing, and you may carry out before a linear process.

Cutting conditions can be set appropriately according to the desired shape. For example, the diameter of the cutting means (end mill) 20 is preferably 3 mm to 20 mm. The rotation speed of the cutting means is preferably 1000 rpm to 60000 rpm, more preferably 10,000 rpm to 40000 rpm. The feed rate of the second cutting means is preferably 500 mm / min to 10000 mm / min, more preferably 500 mm / min to 2500 mm / min. The number of cuts at the cut location can be one round, two rounds, three rounds or more. In the illustrated example, the chamfered portion 4a, the chamfered portion 4b, and the recessed portion 4c are formed in this order, but these may be formed in any appropriate order.

As described above, a cut optically laminated body with a hard coat layer can be obtained.

Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to these examples. Evaluation items in the examples are as follows.

(1) Breaking strength The breaking strength of the optical functional film used in the examples and comparative examples was measured according to JIS K 7161. Specifically, a film is cut into a length of 100 mm and a width of 10 mm to obtain a measurement sample, and the measurement sample is pulled until it breaks using a precision universal testing machine (manufactured by Shimadzu Corporation, product name “Autograph”). Was measured. The tensile condition of the measurement sample was 300 mm / min.
(2) Pencil hardness The surface of the hard coat layer used in the examples and comparative examples was measured according to JIS K 5600.
(3) Storage elastic modulus About the adhesive (adhesive adjacent to a hard-coat layer) used by the Example and the comparative example, the storage elastic modulus was calculated | required from the dynamic viscoelasticity measurement. The dynamic viscoelasticity measurement was performed under the following conditions using a rheometer (dynamic viscoelasticity measuring apparatus) (product name “ARES” manufactured by TA Instruments).
Sample shape 1mm lamination Temperature range -70 ℃ ~ 150 ℃
Temperature increase rate 5 ℃ / min
Measurement frequency 1Hz
Measuring jig Parallel plate (sample is sandwiched between two flat plates)
(4) Cracks For the optical laminate with a hard coat layer (all optical laminates with a hard coat layer constituting the workpiece) obtained in Examples and Comparative Examples, a heat shock test of 200 cycles at −40 ° C. to 85 ° C. The occurrence of cracks in the recesses (concave portions including the curved portion) was visually confirmed and evaluated according to the following criteria. In addition, the length of the crack measured with the optical microscope.
None: Longest crack length of 100 μm or less Occurrence: Longest crack length of more than 100 μm and less than 500 μm Remarkable: Longest crack length of 500 μm or more (5) Processing accuracy About the optical laminated body with a hard-coat layer obtained by the reference examples 1 and 2, the dimension of the long side and the short side was measured with calipers, and processing precision was evaluated.
(6) Blocking For the optical laminate with a hard coat layer obtained in Example 2, Comparative Example 3, and Reference Examples 1 and 2, a stick with a double-sided tape attached to the tip in the state of the workpiece after cutting was hardened It was made to adhere to the center part of the optical laminated body with a coating layer, it lifted, and the following reference | standard evaluated.
A: The optical laminate with a hard coat layer could be lifted one by one. ○: A plurality of optical laminates with a hard coat layer could be lifted, but when shaken, they could be separated one by one. Multiple optical laminates with coat layers were lifted and could not be separated one by one even when shaken

<Example 1>
As a polarizer, a long polyvinyl alcohol (PVA) resin film containing iodine and uniaxially stretched in the longitudinal direction (MD direction) (thickness 12 μm) was used. A pressure-sensitive adhesive layer (thickness 5 μm) is formed on one side of the polarizer, and a long optical function film (HC-TAC film) is bonded to the polarizer so that the longitudinal directions thereof are aligned with each other. It was. 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 is bonded so that the TAC film is on the polarizer side. . A pressure-sensitive adhesive layer is formed on the hard coat layer side of the obtained polarizer / TAC film / HC layer laminate, and another pressure-sensitive adhesive layer is formed on the polarizer side, and a separator is formed on each pressure-sensitive adhesive layer. Bonding was performed to obtain a long optical laminate with a hard coat layer (polarizing plate with a hard coat layer). The storage elastic modulus of the pressure-sensitive adhesive layer adjacent to the HC layer was 1.2 × 10 ⁵ (Pa), and the thickness was 100 μm. The breaking strength of the HC-TAC film was 26N. The pencil hardness of the HC layer was 3H.

The polarizing plate with a hard coat layer obtained as described above was punched into a size of 5.7 inches (length: about 140 mm and width: about 65 mm), and a plurality of punched polarizing plates were stacked to form a workpiece (total thickness: about 10 mm). With the obtained workpiece sandwiched between clamps (jigs), chamfered portions are formed at the two corners of the outer periphery of the workpiece by end milling, and a concave portion (curved line) is formed at the center of the outer peripheral surface where the chamfered portion is formed. The concave part including the part) was formed, and a polarizing plate with a hard coat layer cut as shown in FIG. 3 was obtained. The radius of the curved part was 2.5 mm. Here, the number of blades of the end mill was 3, and the blade angle (twist angle) was 45 °. Moreover, the feed rate of the end mill was 1500 mm / min, and the rotation speed was 30000 rpm.

The finally obtained polarizing plate with a hard coat layer was subjected to the evaluation of the crack. The results are shown in Table 1.

<Example 2>
A polarizing plate with a hard coat layer was produced in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer adjacent to the HC layer was 150 μm. This polarizing plate with a hard coat layer was cut in the same manner as in Example 1. The finally obtained polarizing plate with a hard coat layer that was processed was subjected to the evaluation of the crack. The results are shown in Table 1.

<Example 3>
A polarizing plate with a hard coat layer was produced in the same manner as in Example 1 except that the thickness of the polarizer was 5 μm and that an HC-COP film was used instead of the HC-TAC film. The HC-COP film was a film in which a hard coat (HC) layer (2 μm) was formed on a cycloolefin (COP) film (25 μm), and the breaking strength was 9N. The pencil hardness of the HC layer was 2H. This polarizing plate with a hard coat layer was cut in the same manner as in Example 1. The finally obtained polarizing plate with a hard coat layer that was processed was subjected to the evaluation of the crack. The results are shown in Table 1. Furthermore, processing accuracy and blocking were also evaluated. The results are shown in Table 2.

<Example 4>
A polarizing plate with a hard coat layer was produced in the same manner as in Example 3 except that the storage elastic modulus of the pressure-sensitive adhesive layer adjacent to the HC layer was 2.0 × 10 ⁵ (Pa). This polarizing plate with a hard coat layer was cut in the same manner as in Example 1. The finally obtained polarizing plate with a hard coat layer that was processed was subjected to the evaluation of the crack. The results are shown in Table 1.

<Examples 5 to 8 and Comparative Examples 1 to 7>
The thickness of the polarizer, the optical functional film (and hence its breaking strength), the pencil hardness of the hard coat layer, the thickness of the adhesive layer adjacent to the hard coat layer, the storage elastic modulus of the adhesive layer, and / or the recess A cut polarizing plate with a hard coat layer was produced in the same manner as in Example 1 except that the radius of the curved portion was changed as shown in Table 1. The obtained polarizing plate with a hard coat layer was subjected to evaluation of the crack. The results are shown in Table 1. For Comparative Example 3, processing accuracy and blocking were also evaluated. The results are shown in Table 2.

<Reference Example 1: Examination of blocking>
A hard coat layer-coated polarizing plate was produced in the same manner as in Example 3 except that the number of end mill blades was one. The obtained polarizing plate with a hard coat layer was subjected to the above processing accuracy and blocking evaluation. The results are shown in Table 2.

<Reference Example 2: Examination of blocking>
A cut polarizing plate with a hard coat layer was produced in the same manner as in Comparative Example 3 except that the number of end mill blades was one. The obtained polarizing plate with a hard coat layer was subjected to the above processing accuracy and blocking evaluation. The results are shown in Table 2.

<Evaluation>
As is apparent from Table 1, according to the examples of the present invention, in the method for producing a cut optical laminate with a hard coat layer, the storage elastic modulus of the pressure-sensitive adhesive layer adjacent to the hard coat layer is set within a predetermined range. And by making thickness into more than predetermined value, the crack (especially the crack of the curved part of a recessed part) of a hard-coat layer can be suppressed notably. As a result, the crack of the whole optical laminated body with a hard-coat layer can be suppressed. Furthermore, as is clear from Table 2, in the cutting process of the optical layered body with a hard coat layer including a (soft) adhesive layer having a small storage elastic modulus, blocking is suppressed when the number of end mill blades is large. On the other hand, in the cutting of the optical layered body with a hard coat layer including an adhesive layer having a large (hard) storage elastic modulus, blocking can be suppressed with a smaller number of end mill blades.

The production method of the present invention can be suitably used for production of an optical laminate with a hard coat layer that requires cutting (particularly non-linear machining). The optical layered body with a hard coat layer obtained by the production method of the present invention can be suitably used for a deformed image display unit typified by an automobile instrument panel or a smart watch.

DESCRIPTION OF SYMBOLS 1 Work 20 Cutting means 100 Optical laminated body with a hard-coat layer 101 Optical laminated body with a hard-coat layer 110 Optical film 120 Hard-coat layer 130 Adhesive layer 170 Optical functional film

Claims (9)

Forming a workpiece by stacking a plurality of optical laminates with a hard coat layer, and a rotating shaft extending in the stacking direction of the workpiece and a cutting blade configured as an outermost diameter of a main body rotating around the rotating shaft Cutting the outer peripheral surface of the workpiece by bringing the cutting blade of the cutting means into contact with the outer peripheral surface of the workpiece;
Including
The optical laminate with a hard coat layer includes an optical film, a hard coat layer, an adhesive layer, and a separator in this order,
The pressure-sensitive adhesive layer has a storage elastic modulus G ′ at 25 ° C. of 1.0 × 10 ⁵ (Pa) to 2.5 × 10 ⁵ (Pa), and the thickness of the pressure-sensitive adhesive layer is 50 μm or more.
A method for producing a cut optical layered body with a coat layer. The manufacturing method according to claim 1, comprising cutting the outer peripheral surface of the workpiece non-linearly. The manufacturing method according to claim 1 or 2, wherein the cutting means is an end mill. The manufacturing method according to any one of claims 1 to 3, wherein the optical film is a polarizer or a polarizing plate. The manufacturing method according to claim 4, wherein the optical laminate with a hard coat layer further includes an optical functional film between the polarizer or polarizing plate and the hard coat layer. The manufacturing method according to claim 5, wherein the optical functional film includes at least one selected from a cellulose resin, a cycloolefin resin, and an acrylic resin. The manufacturing method according to claim 5 or 6, wherein the breaking strength of the optical functional film is 35 N or less. The manufacturing method according to any one of claims 2 to 7, wherein the non-linear cutting includes forming a concave portion including a curved portion when the optical laminated body with a hard coat layer is viewed in plan. The manufacturing method of Claim 8 whose radius of the said curved part is 5 mm or less.

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