WO2017126490A1 - 光学積層体の製造方法 - Google Patents
光学積層体の製造方法 Download PDFInfo
- Publication number
- WO2017126490A1 WO2017126490A1 PCT/JP2017/001340 JP2017001340W WO2017126490A1 WO 2017126490 A1 WO2017126490 A1 WO 2017126490A1 JP 2017001340 W JP2017001340 W JP 2017001340W WO 2017126490 A1 WO2017126490 A1 WO 2017126490A1
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- WIPO (PCT)
- Prior art keywords
- pressure
- adhesive layer
- sensitive adhesive
- optical laminate
- precursor
- Prior art date
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
- G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
- G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
- G02B5/3041—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks
- G02B5/305—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks including organic materials, e.g. polymeric layers
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J7/00—Adhesives in the form of films or foils
- C09J7/20—Adhesives in the form of films or foils characterised by their carriers
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
Definitions
- the present invention relates to a method for manufacturing an optical laminate.
- An optical layered body having a polarizing plate is widely used as a polarized light supplying element or a polarized light detecting element in a mobile device such as a notebook personal computer or a mobile phone, or a liquid crystal display device such as a large television.
- the said optical laminated body has the said polarizing plate, the adhesive layer, and the protective film bonded together, for the objective of protecting the surface at the time of manufacture of a liquid crystal display device, for example.
- an optical film for example, a functional film such as a brightness enhancement film is bonded between the polarizing plate and the protective film via an adhesive layer as necessary.
- the optical laminate produced in this manner is attached to the liquid crystal panel via a further pressure-sensitive adhesive layer, and becomes a component part of the liquid crystal display device.
- the pressure-sensitive adhesive layer used for such an optical laminate is formed by, for example, applying a pressure-sensitive adhesive to a polarizing plate (for example, Patent Document 1).
- the thickness of the pressure-sensitive adhesive layer has been required to be thinner than before due to the demand for thin and light liquid crystal display devices. If the thickness of the pressure-sensitive adhesive layer is made thinner than before, the entrapment of bubbles due to the adhesion of foreign substances will be recognized more significantly than the conventional pressure-sensitive adhesive layer.
- the thickness of the pressure-sensitive adhesive layer is made thinner than before, even the size of foreign matter that has not been a problem in the past will be relatively larger than the thickness of the pressure-sensitive adhesive layer. , Not buried in the adhesive layer. As a result, there is a higher risk that bubbles will be caught by foreign substances than before, and the bubble size generated will be larger than before.
- the present invention has been made in view of the above problems, and its purpose is, for example, to prevent deterioration of the quality of the optical laminate due to large bubbles being caught in the bonding surface of the polarizing plate.
- the object is to provide a method for efficient production.
- the present invention includes: [1] A method for producing an optical laminate having at least a protective film, a first pressure-sensitive adhesive layer, and a polarizing plate, Bonding the protective film, the first pressure-sensitive adhesive layer, and the polarizing plate to produce a precursor of an optical laminate; and Placing the precursor of the optical layered body in a temperature lower than 50 ° C. and in an atmosphere of 0.2 MPaG or higher; The manufacturing method of an optical laminated body containing.
- the manufacturing method of an optical laminated body containing.
- [4] The method for manufacturing an optical laminate according to any one of [1] to [3], wherein the optical laminate has a thickness of 200 ⁇ m or less.
- [5] The method for producing an optical laminated body according to any one of [1] to [4], wherein the polarizing plate has a thickness of 10 to 65 ⁇ m or less.
- [6] The method for producing an optical laminated body according to any one of [1] to [5], wherein the protective film has a thickness of 100 ⁇ m or less.
- the production method of the present invention can efficiently reduce the bubble size that can occur during the production of an optical laminate.
- FIG. 1 is a schematic sectional view showing an example of an optical laminate obtained by the production method of the present invention.
- FIG. 2 is a diagram illustrating a method for calculating a bubble size according to an embodiment of the present invention.
- FIG. 3 is a schematic view showing a cross-sectional view of the optical layered body and the relationship between the amounts of warpage.
- FIG. 4 (a) shows the observed bubbles, and FIG. 4 (b) shows that the bubbles have been removed by the manufacturing method of the present invention.
- the production method in the present invention is a method for producing an optical laminate having at least a protective film, a first pressure-sensitive adhesive layer, and a polarizing plate, Bonding the protective film, the first pressure-sensitive adhesive layer, and the polarizing plate to produce a precursor of an optical laminate; and The step of disposing the precursor of the optical layered body in an atmosphere of a temperature of less than 50 ° C. and 0.2 MPaG or more (hereinafter referred to as “precursor post-treatment step” or “precursor including first pressure-sensitive adhesive layer”) It is also called “body post-treatment process”) The manufacturing method of an optical laminated body containing this.
- the bubble size in which the first pressure-sensitive adhesive layer is present can be effectively reduced, and the bubbles can be effectively removed.
- the pressure unit is indicated by “MPaG”
- the pressure means a gauge pressure unless otherwise specified. Furthermore, it is possible to suppress the dimensional change of the obtained optical laminate and the change amount of the warp amount.
- the optical laminate in the present invention has at least a protective film, a first pressure-sensitive adhesive layer, and a polarizing plate.
- the protective film, the first pressure-sensitive adhesive layer, and the polarizing plate are laminated in this order.
- the present invention includes a step of laminating the protective film, the first pressure-sensitive adhesive layer, and the polarizing plate to produce a precursor of an optical laminate, and a precursor of the optical laminate at a temperature of less than 50 ° C. And a step of disposing in an atmosphere of 0.2 MPaG or more.
- a method known in the technical field can be used for the step of bonding the protective film, the first pressure-sensitive adhesive layer, and the polarizing plate to produce the precursor of the optical laminate.
- the protective film and the first pressure-sensitive adhesive layer may be bonded, and then the surface of the first pressure-sensitive adhesive layer opposite to the protective film and the polarizing plate may be bonded.
- the polarizing plate and the first pressure-sensitive adhesive layer may be bonded together, and then the surface of the first pressure-sensitive adhesive layer opposite to the polarizing plate and the protective film may be bonded together.
- the present invention provides a precursor of an optical layered body at a temperature of less than 50 ° C., for example, a temperature of 10 to 40 ° C., in another example, a temperature of 15 to 30 ° C. and a pressurized atmosphere of 0.2 MPaG or more.
- a pressurized atmosphere for example, bubbles in the first pressure-sensitive adhesive layer can be reduced or removed by disposing in a pressurized atmosphere of 0.2 to 0.7 MPaG, in another example, in an atmosphere of 0.2 to 0.6 MPaG.
- the combination of temperature and pressure is not limited.
- the pressure may be 0.2 to 0.5 MPaG.
- the temperature may be 10 to 45 ° C., may be more than 30 ° C. to less than 50 ° C., and may be 35 ° C. to 45 ° C.
- the pressurized atmosphere may be in the range of 0.3 to 0.6 MPaG, 0.35 to 0.55 MPaG.
- the pressure can be 0.7 MPaG or less.
- the lower limit of the treatment temperature is, for example, ⁇ 10 ° C. or higher, and in some embodiments, 5 ° C. or higher.
- the pressure-sensitive adhesive that can be used for the first pressure-sensitive adhesive layer or the like retains fluidity, so that bubbles can be efficiently reduced and / or removed.
- the pressurization time required for the precursor post-treatment step is, for example, 24 hours or less, for example, 1 hour or less, and particularly, 30 minutes or less.
- the pressurization time is the total of the time during which a predetermined pressure is reached after the start of pressurization and then a constant pressure is maintained, unless otherwise specified. Further, the pressure may be increased stepwise, or the pressure may be increased at a constant rate of increase.
- the decompression time after pressurization can be appropriately set according to the applied pressure, temperature, and the like.
- the decompression time is, for example, 0.5 to 30 minutes, and in another embodiment, 8 to 30 minutes.
- the decompression time may be 5 to 30 minutes, for example, 8 to 30 minutes.
- the decompression time may be 8 to 30 minutes.
- the depressurization time means the time from the start of depressurization until reaching the normal pressure unless otherwise specified.
- the pressure may be reduced stepwise, or the pressure may be reduced at a constant rate of change.
- setting the pressure of the pressure treatment to 0.2 to 0.7 MPaG means that an arbitrary value can be taken within such a range.
- the pressure of the pressure treatment may be 0.3 to 0.65 MPaG, or 0.4 to 0.6 MPaG.
- these values can be appropriately set according to the thickness of the pressure-sensitive adhesive layer subjected to bubble removal and the number of pressure-sensitive adhesive layers, as long as they do not depart from the scope of the present invention.
- the present invention further reduces or removes the bubbles existing in the first pressure-sensitive adhesive layer in the stage before producing the precursor of the optical laminate, if necessary.
- precursor pretreatment step the method for producing an optical laminate may include a precursor pretreatment step after the protective film and the first pressure-sensitive adhesive layer are bonded, and then a precursor post-treatment step. After pasting the first pressure-sensitive adhesive layer and the polarizing plate, a post-treatment step of the precursor may be included. By including a precursor pretreatment step in the previous stage of producing the precursor of the optical layered body, bubbles can be removed more effectively.
- the air bubbles existing in the first pressure-sensitive adhesive layer are air bubbles existing at the interface between the first pressure-sensitive adhesive layer and the adjacent layer, for example, the interface between the protective film and the first pressure-sensitive adhesive layer. It may be a bubble present at the interface between the first pressure-sensitive adhesive layer and the polarizing plate, a bubble present inside the first pressure-sensitive adhesive layer, or a combination thereof. Air bubbles may be used. Such an example corresponds not only to the first pressure-sensitive adhesive layer but also to a second pressure-sensitive adhesive layer and a third pressure-sensitive adhesive layer described later.
- reducing the bubbles means reducing the size of the bubbles caught in the pressure-sensitive adhesive layer.
- the mechanism by which bubbles are reduced and removed is not limited to this theory.
- the bubble size can be reduced by pushing the bubbles present in the adhesive layer out of the edge of the optical laminate. It is estimated to be. Therefore, according to the production method of the present invention, it is possible to efficiently produce a high-quality optical laminate without the inclusion of bubbles having a size that degrades the quality of the optical laminate. As a result, there is an effect that the productivity and yield of the optical laminated body can be increased (the defective rate can be reduced).
- the production method of the present invention performs bubble removal under the above-mentioned predetermined temperature and pressure conditions, it is possible to suppress dimensional changes and warpage changes that may occur due to contraction of the polarizing plate or the like. Furthermore, the dimensional change of the obtained optical laminate and the amount of change in warpage can be suppressed.
- the precursor of the optical layered body is cut into a precursor of the chip-shaped optical layered body.
- the process (it is also called a cutting process) to perform may be further included.
- disconnecting raw materials, such as a protective film it may paste
- the above-described bubble removing step may be performed after the cutting step. This is because if the size (area) of the precursor of the optical laminate is small, bubbles can be efficiently extruded from the precursor of the optical laminate.
- the production method of the present invention may include a further cutting step known in the technical field and a step of laminating other optical members, if necessary, following the precursor post-treatment step.
- the present invention is also a method for producing an optical laminate as described above, wherein the optical laminate further has a functional film and a second pressure-sensitive adhesive layer, Furthermore, the process of bonding the said functional film and the said 2nd adhesive layer, and the process of arrange
- post-treatment step of a precursor containing a second pressure-sensitive adhesive layer According to the production method of the present invention, at least the bubble size in which the second pressure-sensitive adhesive layer exists can be effectively reduced, and the bubbles can be effectively removed. Furthermore, it is possible to suppress the dimensional change of the obtained optical laminate and the change amount of the warp amount.
- a protective film, a first pressure-sensitive adhesive layer, a functional film, a second pressure-sensitive adhesive layer, and a polarizing plate may be bonded in this order.
- the protective film, the first pressure-sensitive adhesive layer, the polarizing plate, the second pressure-sensitive adhesive layer, and the functional film may be bonded in this order.
- the laminating order and laminating mode of these layers can be set as appropriate.
- the bubbles present in the second pressure-sensitive adhesive layer are bubbles present at the interface between the second pressure-sensitive adhesive layer and the adjacent layer, for example, the interface between the functional film and the second pressure-sensitive adhesive layer. It may be a bubble present at the interface between the second pressure-sensitive adhesive layer and the polarizing plate, or may be a bubble present inside the second pressure-sensitive adhesive layer, and is present in a combination thereof. It may be a bubble.
- a protective film For example, a protective film, a first pressure-sensitive adhesive layer, a functional film, and a second pressure-sensitive adhesive layer are bonded together, and a precursor of the obtained optical laminate is formed at a temperature of less than 50 ° C. and 0.2 MPaG.
- the optical layered body may be obtained by reducing or removing bubbles present in the pressure-sensitive adhesive layer.
- the second pressure-sensitive adhesive layer is disposed in an atmosphere having a temperature of less than 50 ° C. and a pressure of 0.2 MPaG or more, so that bubbles existing in the second pressure-sensitive adhesive layer can be efficiently removed. Can be removed.
- the step of bonding the protective film, the first pressure-sensitive adhesive layer, the functional film, the second pressure-sensitive adhesive layer, and the polarizing plate is also performed by a method known in the technical field, and the pressure-sensitive adhesive layer.
- the order of pasting etc. can also be selected suitably.
- a precursor of the optical laminate is obtained.
- the post-treatment step of the precursor including the second pressure-sensitive adhesive layer may be performed together with the post-treatment step of the precursor including the first pressure-sensitive adhesive layer.
- the first and second pressure-sensitive adhesive layers may be combined.
- a post-treatment process of the precursor may be performed.
- the “post-treatment step of the precursor including the second pressure-sensitive adhesive layer” is included in the “pre-treatment step of the precursor”.
- the precursor post-treatment step including the second pressure-sensitive adhesive layer When the precursor post-treatment step including the second pressure-sensitive adhesive layer is performed together with the precursor post-treatment step including the first pressure-sensitive adhesive layer, the precursor post-treatment step may be performed according to the conditions for the precursor post-treatment step. Moreover, when performing the post-process of the precursor containing the first pressure-sensitive adhesive layer and the post-process of the precursor containing the second pressure-sensitive adhesive layer independently, conditions such as the processing temperature and pressure are , May be the same or different. These conditions can be set as appropriate depending on the types and thicknesses of the applied first and second pressure-sensitive adhesive layers.
- the post-treatment step of the precursor including the second pressure-sensitive adhesive layer may be performed at a temperature of less than 50 ° C., for example, 10 to 40 ° C., in another example, 15 to 30 ° C.
- the second pressure-sensitive adhesive is placed in an atmosphere having a temperature of 0.2 MPaG or more, for example, in an atmosphere of 0.2 to 0.7 MPaG, and in another example, in an atmosphere of 0.2 to 0.6 MPaG. Bubbles existing in the agent layer can be reduced or removed.
- the combination of temperature and pressure is not limited. For example, when the temperature is 15 to 30 ° C., the pressure may be 0.2 to 0.5 MPaG.
- the temperature may be 10 to 45 ° C., may be more than 30 ° C. to less than 50 ° C., and may be 35 ° C. to 45 ° C.
- the pressurized atmosphere may be in the range of 0.3 to 0.6 MPaG, 0.35 to 0.55 MPaG.
- the pressure can be 0.7 MPaG or less.
- the lower limit of the processing temperature is, for example, 5 ° C or higher.
- the pressure-sensitive adhesive that can be used for the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer retains fluidity, so that bubbles can be efficiently reduced and / or removed.
- the pressurization time required for the precursor post-treatment step is, for example, 24 hours or less, for example, 1 hour or less, and particularly, 30 minutes or less.
- the treatment is performed for 3 to 30 minutes.
- the decompression time after pressurization can be appropriately set according to the applied pressure, temperature, and the like.
- the decompression time is, for example, 0.5 to 30 minutes, and in another embodiment, 8 to 30 minutes.
- the decompression time may be 5 to 30 minutes, for example, 8 to 30 minutes.
- the decompression time may be 8 to 30 minutes.
- the production method of the present invention it is possible to efficiently produce a high-quality optical laminate without the inclusion of bubbles having a size that degrades the quality of the optical laminate. As a result, there is an effect that the productivity and yield of the optical laminated body can be increased (the defective rate can be reduced). Furthermore, since the production method of the present invention performs bubble removal under the above-mentioned predetermined temperature and pressure conditions, it is possible to suppress dimensional changes and warpage changes that may occur due to contraction of the polarizing plate or the like. Furthermore, the dimensional change of the obtained optical laminate and the amount of warpage can be suppressed, and as a result, the productivity and yield of the optical laminate can be increased (the defect rate can be reduced).
- the precursor of the optical layered body is cut into a precursor of the chip-shaped optical layered body.
- the process (it is also called a cutting process) to perform may be further included.
- disconnecting raw materials, such as a protective film it may paste
- the above-described bubble removing step may be performed after the cutting step. This is because if the size (area) of the precursor of the optical laminate is small, bubbles can be efficiently extruded from the precursor of the optical laminate.
- the present invention is also the above-described optical laminate manufacturing method, wherein the optical laminate further includes a third pressure-sensitive adhesive layer and a release paper, Furthermore, the step of bonding the third pressure-sensitive adhesive layer and the release paper, and the step of disposing the third pressure-sensitive adhesive layer in an atmosphere having a temperature of less than 50 ° C. and 0.2 MPaG or more (hereinafter, “ Also referred to as a precursor post-treatment step including a third pressure-sensitive adhesive layer), The manufacturing method of an optical laminated body containing is provided. By including the above steps, at least the bubble size in which the third pressure-sensitive adhesive layer exists can be effectively reduced, and the bubbles can be effectively removed. Furthermore, it is possible to suppress the dimensional change of the obtained optical laminate and the change amount of the warp amount.
- the protective film, the first pressure-sensitive adhesive layer, the functional film, the second pressure-sensitive adhesive layer, the polarizing plate, the third pressure-sensitive adhesive layer, and the release paper are laminated in this order. Good.
- the protective film, the first pressure-sensitive adhesive layer, the polarizing plate, the second pressure-sensitive adhesive layer, the functional film, the third pressure-sensitive adhesive layer, and the release paper are laminated in this order. Good.
- the laminating order and laminating mode of these layers can be set as appropriate.
- the air bubbles present in the third pressure-sensitive adhesive layer are air bubbles existing at the interface between the third pressure-sensitive adhesive layer and the adjacent layer, for example, the interface between the polarizing plate and the third pressure-sensitive adhesive layer. It may be a bubble present at the interface between the third pressure-sensitive adhesive layer and the release paper, or may be a bubble present inside the third pressure-sensitive adhesive layer, and exists in a combination thereof. Air bubbles may be used.
- a protective film For example, a protective film, a first pressure-sensitive adhesive layer, a functional film, a second pressure-sensitive adhesive layer, a polarizing plate, a third pressure-sensitive adhesive layer, and a release paper are laminated, and the obtained optical laminate
- the precursor may be disposed in an atmosphere at a temperature of less than 50 ° C.
- the “post-treatment step of the precursor” includes the “post-treatment step of the precursor including the third pressure-sensitive adhesive layer”.
- the third pressure-sensitive adhesive layer is disposed in an atmosphere having a temperature of less than 50 ° C. and a pressure of 0.2 MPaG or more, so that bubbles existing in the third pressure-sensitive adhesive layer can be efficiently removed. Can be removed.
- the step of bonding the third pressure-sensitive adhesive and the release paper to the polarizing plate is also performed by a method known in the technical field, and the order in which the pressure-sensitive adhesive layer and the like are bonded can be selected as appropriate. Through this step, a precursor of the optical laminate is obtained.
- the post-treatment step of the precursor including the third pressure-sensitive adhesive layer may be performed together with the post-treatment step of the precursor including the first pressure-sensitive adhesive layer, and the post-treatment of the precursor including the second pressure-sensitive adhesive layer. You may perform with a process and you may perform the post-process of the precursor containing a 3rd adhesive layer independently. Furthermore, the order of the post-treatment steps of the precursor including the first to third pressure-sensitive adhesive layers is not limited.
- a post-processing step of a precursor including a third pressure-sensitive adhesive layer, a post-processing step of a precursor including the first pressure-sensitive adhesive layer, and a post-processing step of a precursor including the second pressure-sensitive adhesive layer When performed together, for example, it can be performed according to the conditions for the post-treatment step of the precursor including the first pressure-sensitive adhesive layer. Also, When the post-treatment steps of these precursors are performed independently, conditions such as treatment temperature and pressure may be the same or different.
- the precursor post-processing step including the first pressure-sensitive adhesive layer and the precursor post-processing step including the second pressure-sensitive adhesive layer are performed in the same step, and the precursor including the third pressure-sensitive adhesive layer
- the conditions such as the treatment temperature and pressure may be the same or different in both cases. These conditions can be set as appropriate depending on the types and thicknesses of the first to third pressure-sensitive adhesive layers applied.
- the post-treatment step of the precursor including the third pressure-sensitive adhesive layer may be performed at a temperature of less than 50 ° C., for example, 10 to 40 ° C., in another example, 15 to 30 ° C.
- the third pressure-sensitive adhesive is placed in an atmosphere having a temperature of 0.2 MPaG or more, for example, in an atmosphere of 0.2 to 0.7 MPaG, and in another example, in an atmosphere of 0.2 to 0.6 MPaG. Bubbles existing in the agent layer can be reduced or removed.
- the combination of temperature and pressure is not limited. For example, when the temperature is 15 to 30 ° C., the pressure may be 0.2 to 0.5 MPaG.
- the temperature may be 10 to 45 ° C., may be more than 30 ° C. to less than 50 ° C., and may be 35 ° C. to 45 ° C.
- the pressurized atmosphere may be in the range of 0.3 to 0.6 MPaG, 0.35 to 0.55 MPaG.
- the pressure can be 0.7 MPaG or less.
- the lower limit of the processing temperature is, for example, 5 ° C or higher.
- the pressure-sensitive adhesive that can be used for the first pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer, and the third pressure-sensitive adhesive layer retains fluidity, so that bubbles can be efficiently discharged. Can be reduced and / or eliminated.
- the pressurization time required for the precursor post-treatment step is, for example, 24 hours or less, for example, 1 hour or less, and particularly, 30 minutes or less.
- the treatment is performed for 3 to 30 minutes.
- the decompression time after pressurization can be appropriately set according to the applied pressure, temperature, and the like.
- the decompression time is, for example, 0.5 to 30 minutes, and in another embodiment, 8 to 30 minutes.
- the decompression time may be 5 to 30 minutes, for example, 8 to 30 minutes.
- the decompression time may be 8 to 30 minutes.
- the production method of the present invention it is possible to efficiently produce a high-quality optical laminate without the inclusion of bubbles having a size that degrades the quality of the optical laminate. As a result, there is an effect that the productivity and yield of the optical laminated body can be increased (the defective rate can be reduced). Furthermore, since the production method of the present invention performs bubble removal under the above-mentioned predetermined temperature and pressure conditions, it is possible to suppress dimensional changes and warpage changes that may occur due to contraction of the polarizing plate or the like. Furthermore, the dimensional change of the obtained optical laminate and the amount of warpage can be suppressed, and as a result, the productivity and yield of the optical laminate can be increased (the defect rate can be reduced).
- the precursor of the optical layered body is cut into a precursor of the chip-shaped optical layered body.
- the process (it is also called a cutting process) to perform may be further included.
- disconnecting raw materials, such as a protective film it may paste
- the above-described bubble removing step may be performed after the cutting step. This is because if the size (area) of the precursor of the optical laminate is small, bubbles can be efficiently extruded from the precursor of the optical laminate.
- the step of bonding the polarizing plate, the third pressure-sensitive adhesive layer, and the release paper is performed by a method known in the technical field, and the order in which the pressure-sensitive adhesive layer and the like are bonded can be appropriately selected. Through this step, a precursor of the optical laminate is obtained.
- the optical laminate is an optical laminate obtained by pressure-bonding films with the pressure-sensitive adhesive layer by a pair of pressure rollers that form a nip portion. May be.
- the thickness of the polarizing plate having the polarizer protective film and the polarizer has been reduced.
- the thickness of the polarizing plate is reduced, physical property changes due to thermal contraction of the polarizer can occur.
- thermal contraction is unlikely to occur in the polarizing plate, and the dimensional change and the warpage amount change of the optical laminate can be suppressed.
- the pressure-sensitive adhesive layer is more preferably made of a pressure-sensitive pressure-sensitive adhesive.
- films, polarizing plates and the like can be bonded to each other by applying pressure at room temperature.
- the pressure-sensitive adhesive may have a storage elastic modulus at 25 ° C. of 0.05 MPa to 1.0 MPa.
- the storage elastic moduli of the first to third pressure-sensitive adhesive layers may be the same or different from each other.
- the storage elastic modulus of the first pressure-sensitive adhesive layer is 0.1 to 0.3 MPa
- the storage elastic modulus of the second pressure-sensitive adhesive layer is 0.4 to 0.7 MPa
- the third pressure-sensitive adhesive layer The storage elastic modulus is 0.3 to 0.6 MPa.
- the method for producing an optical laminate according to the present invention includes a post-treatment step of a precursor that arranges a precursor of the optical laminate in an atmosphere of a temperature of less than 50 ° C. and 0.2 MPaG or more, and is therefore generally used.
- An adhesive harder than the adhesive can be used.
- strength of an adhesive layer can be raised if the storage elastic modulus in 50 degreeC of an adhesive uses the said range, the thickness of an adhesive layer can be made still thinner.
- the thickness of the pressure-sensitive adhesive layer 1 can be 1 ⁇ m to 70 ⁇ m.
- the thickness of the first pressure-sensitive adhesive layer may be 15 to 25 ⁇ m
- the thickness of the second pressure-sensitive adhesive layer may be 10 to 20 ⁇ m
- the thickness of the third pressure-sensitive adhesive layer may be 15 to 25 ⁇ m.
- the thickness of the first to third pressure-sensitive adhesive layers was about 25 ⁇ m. According to the method for producing an optical laminate according to the present invention, even when the thickness of the pressure-sensitive adhesive layer is less than 25 ⁇ m, there is no optical lamination in which bubbles having a size that degrades the quality of the optical laminate are not caught. The body can be manufactured. Moreover, if the thickness of an adhesive layer is in the said range, the thickness of the optical laminated body obtained can be made thinner.
- the bubbles present in the first to third pressure-sensitive adhesive layers can be commercially satisfied, that is, the quality of the optical laminate is not deteriorated. Can be made smaller.
- the bubble diameter is 600 ⁇ m or less, preferably 400 ⁇ m or less, more preferably 200 ⁇ m or less, and even more preferably 100 ⁇ m or less. Can be made smaller.
- the bubble size can be measured as follows.
- a method for calculating the bubble size will be described with reference to FIG.
- FIG. 2 is a diagram for explaining a method for calculating the bubble size of the present invention
- (a) is a diagram for explaining a method for calculating the size of a dot-like bubble (dot-like bubble)
- (b) are the figures explaining the method of calculating the magnitude
- the arrow E shown in FIGS. 2A and 2B indicates the optical axis direction of the polarizing plate.
- the dotted bubble size ( ⁇ 1) is a rectangle that has sides in the optical axis direction of the polarizing plate and the direction perpendicular thereto and circumscribes the dotted bubble to be measured
- the length of the side in the optical axis direction of the polarizing plate is a
- the length of the side in the direction orthogonal to the optical axis direction of the polarizing plate is b
- the following formula (1) ⁇ 1 (a + b) / 2 (1) It is requested from.
- the spot-like bubble size ( ⁇ 2) has spots in the optical axis direction of the polarizing plate and the direction perpendicular thereto, and constitutes the spot-like bubble to be measured.
- the length of the side in the optical axis direction of the polarizing plate in the smallest rectangle that encloses all the bubbles (the rectangle indicated by the broken line in FIG. 2B) is c, and is orthogonal to the optical axis direction of the polarizing plate.
- a bubble group in which a plurality of relatively small bubbles are arranged in an annular shape in a range of about 500 ⁇ m in diameter is defined as one spotted bubble.
- the other bubbles were defined as point bubbles.
- the average change rate of bubble size may be calculated.
- the average change rate of the bubble size is a ratio calculated from a value obtained by dividing a difference obtained by subtracting the bubble size after the pressure treatment from the bubble size before the pressure treatment by the bubble size before the pressure treatment. (The specific calculation method is described in the examples). In this specification, the higher the bubble size change rate, the more efficiently the bubble size can be reduced and the bubble can be removed.
- the average change rate of the bubble size is, for example, 1 to 70%, particularly 10 to 60%. Further, the evaluation regarding the reduction and removal of bubbles may be evaluated by calculating the bubble reduction rate (the specific calculation method is described in the examples).
- the value of the bubble reduction rate is 100%, it means that the bubble size is reduced in all the observed bubbles.
- the bubble reduction rate is, for example, 10 to 100%, and particularly 30 to 100%.
- the evaluation regarding the reduction and removal of the bubbles may be performed by calculating a rate at which the bubble size is reduced by 10% or more.
- the ratio of bubbles with a bubble size reduced by 10% or more may be 100%.
- the ratio of bubbles with a bubble size reduced by 10% or more is, for example, 20 to 100%.
- the bubble size may be measured and evaluated by a method known in the art.
- the method for heat-treating the bonded polarizing plates under pressure under the above-mentioned atmosphere is not particularly limited.
- the polarizing plate can be heat-treated using a known autoclave.
- the surrounding gas surrounding the bonded polarizing plate to be heated is not particularly limited as long as it does not adversely affect the film such as the polarizing plate.
- it may be an inert gas such as air or nitrogen gas. Usually, air is applied.
- FIG. 1 is a cross-sectional view showing a schematic configuration of the optical laminated body 10.
- the optical laminate 10 includes a protective film 2, a first pressure-sensitive adhesive layer 1a, a functional film 4, a second pressure-sensitive adhesive layer 1b, a polarizing plate 3, and a third pressure-sensitive adhesive layer. 1c, and release paper 5.
- the first to third pressure-sensitive adhesive layers may be collectively referred to as pressure-sensitive adhesive layer 1.
- the method of bonding the films together through the pressure-sensitive adhesive layer 1 is not particularly limited.
- a method of pressure-bonding films with a pair of pressure rollers that form a nip portion that is, a lamination method (see, for example, JP-A-2005-213314) may be employed.
- a lamination method when the films are bonded to each other, air bubbles can be caught in the pressure-sensitive adhesive layer 1. For this reason, there is no entrapment of bubbles of such a size that the quality of the optical laminate is deteriorated in the pressure-sensitive adhesive layer by subjecting the polarizing plate or the like bonded by the lamination method to the post-treatment process of the precursor according to the present invention.
- An optical laminated body can be manufactured efficiently.
- the optical laminate in the present invention is an optical laminate having at least a protective film, a first pressure-sensitive adhesive layer, and a polarizing plate
- the configuration is limited to the optical laminate 10 shown in FIG. is not.
- a plurality of functional films 4 may be provided in the optical laminate 10 shown in FIG. 1, a plurality of functional films 4 may be provided.
- the thickness of the optical laminate is, for example, 300 ⁇ m or less, for example, 200 ⁇ m or less. According to the manufacturing method according to the present invention, it is possible to suppress a change in dimensions and a change in the amount of warping even with an optical laminate having such a thickness. As a result, for example, in a liquid crystal display, a film with a high dimensional accuracy requirement can be manufactured as an optical film to be attached to a narrow frame (frame) surrounding a liquid crystal panel. Furthermore, the warpage amount of the liquid crystal display after the optical film is attached can be suppressed by suppressing the warpage amount.
- the pressure-sensitive adhesive layer 1 (the pressure-sensitive adhesive layer 1a, the pressure-sensitive adhesive layer 1b, and the pressure-sensitive adhesive layer 1c) is not particularly limited, and is formed by applying a known pressure-sensitive adhesive used in the technical field.
- Specific examples of such an adhesive include acrylic, rubber, urethane, silicone, and polyvinyl ether resins. Among these, an adhesive having an acrylic resin having excellent transparency, weather resistance, heat resistance and the like as a base polymer is more preferable.
- a pressure sensitive adhesive (pressure sensitive adhesive) can be used suitably as an adhesive.
- the “pressure-sensitive adhesive” is not particularly limited.
- the pressure-sensitive adhesive is composed of, for example, an acrylic polymer; a silicone polymer; a polyester, polyurethane, polyether or the like as a base polymer. Like acrylic polymers, it has excellent optical transparency, retains appropriate wettability and cohesion, has excellent adhesion to substrates, and has weather resistance, heat resistance, etc. It is more preferable to select and use one that does not cause peeling problems such as floating and peeling under humidification conditions.
- adheresive may be used alone or in combination of two or more.
- the optical laminate has a plurality of pressure-sensitive adhesive layers, specifically, for example, as shown in FIG. 1, when the optical laminate 10 has pressure-sensitive adhesive layers 1a to 1c, All of the adhesive layers 1a to 1c may be made of one type (the same) adhesive, and the types of adhesive may be different from one adhesive to another depending on the adhesive layer. Further, all the pressure-sensitive adhesive layers 1a to 1c may have the same thickness, or the thickness of each pressure-sensitive adhesive layer may be different.
- a known protective film is suitably used. More specifically, examples of the protective film 2 include known protective films such as a polyester film, a polyethylene terephthalate (PET) film, a polyethylene film, a polypropylene film, and a polystyrene film.
- PET polyethylene terephthalate
- the thickness of the protective film 2 is not particularly limited, but is, for example, 10 ⁇ m to 100 ⁇ m. In another embodiment, the protective film 2 has a thickness of 35 to 45 ⁇ m.
- the polarizing plate 3 As the polarizing plate 3, a known polarizing plate is preferably used. Specifically, the polarizing plate 3 includes a known polarizing plate in which protective films are attached to both sides of a polarizer. Further, as the polarizing plate 3, a known polarizing plate in which a protective film is attached to one side of the polarizer may be used. For example, a known adhesive may be used for attaching the polarizer and the protective film, and as an example, a polyvinyl alcohol-based adhesive may be used.
- polarizer examples include, for example, a film made of polyvinyl alcohol (PVA), partially formalized polyvinyl alcohol, partially saponified ethylene-vinyl acetate copolymer, hydrophilic polymer such as cellulose, and the like.
- PVA polyvinyl alcohol
- examples thereof include films that have been subjected to dyeing treatment with a pigment such as iodine and various treatments such as hue adjustment.
- the manufacturing method of a polarizer is not limited to the said manufacturing method, A well-known polarizer is used suitably.
- protection film examples include cellulose acetate resin films such as TAC (triacetyl cellulose) film, cycloolefin resin (COP) film, and diacetyl cellulose; polyester resin films such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate.
- TAC triacetyl cellulose
- COP cycloolefin resin
- diacetyl cellulose diacetyl cellulose
- polyester resin films such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate.
- a polycarbonate resin film an acrylic resin film
- a known film such as a polypropylene resin film.
- the thickness of the polarizing plate 3 is not particularly limited, but is, for example, 10 to 100 ⁇ m, particularly 10 to 65 ⁇ m.
- the polarizing plate 3 may further include other layers in addition to the above three layers (protective film, polarizer, protective film) as long as there is no practical problem, and a protective film is provided only on one surface of the polarizer. You may prepare.
- the polarizing plate 3 may further include an adhesive layer that adheres the polarizer and the protective film. When the thickness of the polarizing plate 3 is in such a range, for example, the liquid crystal display can be thinned.
- a film with a high dimensional accuracy requirement is manufactured as an optical film to be attached to a narrow frame (frame) surrounding a liquid crystal panel (frame). Can do. Furthermore, the warpage amount of the liquid crystal display after the optical film is attached can be suppressed by suppressing the warpage amount.
- the thickness of the polarizer included in the polarizing plate is, for example, 2 to 30 ⁇ m, and in another aspect, 5 to 15 ⁇ m.
- the functional film 4 is a film and layer having optical functionality, and examples thereof include a brightness enhancement film layer, a retardation film layer, an antiglare layer, a conductive layer, a hard coat layer, and an antireflection layer. .
- the functional film 4 may be used in combination of these layers, or may be used alone.
- the thickness of the functional film 4 is, for example, 5 to 50 ⁇ m.
- the 3rd adhesive layer 1c is formed in the surface at the side stuck to the liquid crystal panel etc. of the optical laminated body 10, and a peeling film ( A protective film or a separator).
- the cutting step is a step of cutting the long optical laminate (also referred to as “polarizing plate original fabric”) into a chip-like optical laminate when the optical laminate is a long polarizing plate.
- the cutting method is not particularly limited as long as the polarizing plate original can be cut into a chip-shaped optical laminate having a predetermined size.
- a known cutter such as a blade or a laser cutter is preferably used.
- the size of the chip-shaped optical laminate can be appropriately set according to the purpose, as is the case with the size of the liquid crystal panel, but is generally preferably 1.5 inches to 60 inches diagonally to the liquid crystal panel. More preferably, it is 1.5 inches to 18 inches applied to a small to medium-sized liquid crystal panel, and further preferably 3.5 inches to 6 inches applied to a portable electronic terminal.
- the order of the “precursor post-treatment step” and the “cutting step” is not particularly limited, and the cutting step may be performed after the precursor post-treatment step, and the precursor post-treatment step is performed after the cutting step. May be.
- the optical laminated body When the optical laminated body is a long optical laminated body, it is cut into a chip-shaped optical laminated body having a predetermined size to reduce the size (area) of the optical laminated body, and then the bubbles By performing the step of reducing or removing the bubbles, the bubbles existing in the pressure-sensitive adhesive layer can be reduced or removed more efficiently.
- the production method of the present invention it is possible to efficiently produce a polarizing plate in which no bubbles are caught in the pressure-sensitive adhesive layer. As a result, the productivity and yield of the polarizing plate can be increased (the defective rate can be reduced).
- shrinkage of the optical laminate can be reduced.
- the amount of change in the long side direction, the long side length in the obtained optical laminate from (after L AC), represented by the difference obtained by subtracting the length of the long side in the precursor of the optical laminate (L AC ago) It is.
- the amount of change in the long side direction is between ⁇ 0.02 and +0.02 mm, for example, ⁇ 0.01 to +0. .01 mm.
- the amount of change in the short-side direction, the short side length in the obtained optical laminate from (after W AC), the difference obtained by subtracting the short side length in the precursor of the optical laminate (W AC ago) Indicated.
- the amount of change in the short side direction is between ⁇ 0.02 and +0.02 mm, for example, ⁇ 0.01 to +0. .01 mm.
- the amount of change takes a negative value, it means that the precursor of the optical laminate contracted and an optical laminate was obtained.
- the amount of change in the long side direction (hereinafter sometimes referred to as “long side change amount”) and the amount of change in the short side direction (hereinafter also referred to as “short side change amount”) are within the above range.
- the optical laminate is not significantly contracted, and the dimensional accuracy required for a thin optical laminate can be maintained.
- dimensional change rate long side (L AC after -L AC before) / L AC before ⁇ 100
- “Dimensional change rate long side ” is, for example, in the range of ⁇ 0.05 to 0.10%
- “Dimensional change rate short side ” is, for example, in the range of ⁇ 0.03 to 0.05%.
- the dimensional change rate is within the above range, the dimensional accuracy required for a thin optical laminate can be maintained without causing significant shrinkage of the optical laminate.
- the amount of change takes a negative value, it means that the precursor of the optical laminate contracted and an optical laminate was obtained.
- the precursor of the optical laminate is more than 30 ° C. to less than 50 ° C., specifically, a temperature of 35 ° C. to 45 ° C.
- the “dimensional change rate long side ” of the precursor of the optical laminate can be in the range of ⁇ 0.01 to 0.01%, for example.
- the “dimensional change rate short side ” of the precursor of the laminate may be, for example, in the range of ⁇ 0.01 to 0.01%.
- the manufacturing method according to the present invention it is possible to reduce the warpage of the optical laminated body.
- Such warpage can be evaluated by measuring, for example, the amount of change in warpage in the present invention.
- the magnitude of the warp of the optical laminate can be evaluated by determining the amount of change in the warp from the difference obtained by subtracting the warp of the precursor of the optical laminate from the warp of the optical laminate.
- the amount of warpage in the optical laminate 10 is obtained by placing the optical laminate 10 on a horizontal glass panel 60 so that the direction of curl is the orientation shown in FIG.
- the amount of warping of the precursor of the optical laminate is the same as that of the optical laminate, for example, the direction of curl of the precursor of the optical laminate obtained through the manufacturing method according to the present invention as shown in FIG. It mounts on a horizontal glass panel so that it may become, and measures the relative height of the rise
- the amount of change in the amount of warpage is the difference obtained by subtracting the amount of warpage of the precursor of the optical laminate from the amount of warpage of the optical laminate obtained as described above.
- the change amount of the warp amount is indicated by an absolute value, it means that the warp of the optical laminate increases as the absolute value of the change amount increases.
- FIG. 3 shows a schematic diagram illustrating a cross-sectional view of the optical layered body and the relationship between the amounts of warpage.
- the warpage of the optical laminate in the protective film direction is described as the occurrence of warpage in the positive curl direction, and the value of the warp amount is indicated by a positive value.
- the warpage of the optical laminate toward the surface opposite to the protective film is described as the occurrence of warping in the reverse curl direction, and the value of the warping amount is indicated by a negative value.
- the amount of warpage of the optical laminate that is, the amount of warpage of the optical laminate after at least one of reducing the bubble size and removing the bubble is, for example, ⁇ 5 to +5 mm, and in another embodiment, is ⁇ 2 to +2 mm. .
- the warp of the optical laminated body occurs, for example, in the positive curl direction, and the change amount of the warp amount is between ⁇ 1 and +1 mm, and in another aspect, ⁇ 0.5 to +0. Between 5 mm.
- the amount of change in the warping amount in such a range, it is possible to prevent the appearance of the polarizing plate from being adversely affected.
- the end of the liquid crystal display device It is also possible to avoid the occurrence of light leakage and the deterioration of display quality.
- the amount of change in warpage can be ⁇ 1 to +1 mm.
- the optical layered body obtained by the present invention can be applied to, for example, a liquid crystal display device.
- the optical laminate obtained by the present invention may be configured to be adhered to a liquid crystal panel.
- the liquid crystal panel includes a known liquid crystal panel that includes a pair of substrates such as a glass substrate and a liquid crystal layer, and an alignment film is disposed between the substrate and the liquid crystal layer.
- a known liquid crystal panel that includes a pair of substrates such as a glass substrate and a liquid crystal layer, and an alignment film is disposed between the substrate and the liquid crystal layer.
- Examples include an electric field type liquid crystal cell, a TFT (Thin Film Transistor) type liquid crystal cell, an STN (Super Twisted Nematic) type liquid crystal cell, an IPS (In-Plane Switching) type liquid crystal cell, a VA (Vertical Alignment) type liquid crystal cell, and the like.
- the liquid crystal display device can be manufactured by sticking the polarizing plate and the liquid crystal panel according to the present invention through an adhesive layer.
- the liquid crystal display device according to the present invention is formed by adhering the optical laminate according to the present invention to a liquid crystal panel, a high quality liquid crystal display device can be provided. For this reason, it can be a liquid crystal display device with high productivity and yield.
- Precursor A Protective film with adhesive-A1: A PET resin film (thickness 38 ⁇ m) coated with an acrylic resin adhesive (thickness 15 ⁇ m, storage elastic modulus 0.2 MPa) (manufactured by Fujimori Kogyo).
- Second pressure-sensitive adhesive acrylic resin-based pressure-sensitive adhesive, thickness 15 ⁇ m, storage elastic modulus 0.5 MPa
- Third pressure-sensitive adhesive acrylic resin-based pressure-sensitive adhesive, thickness 20 ⁇ m, storage modulus 0.4 MPa
- Polarizing plate-A1 manufactured by Sumitomo Chemical Co., Ltd., SR024CUT, thickness 20 ⁇ m, polarizing plate configuration: PVA / COP, polyvinyl alcohol adhesive Release paper: PET resin film (thickness 38 ⁇ m) coated with a silicon release agent Film: manufactured by 3M, brightness enhancement film, APF-V3-HC, thickness 28 ⁇ m
- Precursor B Protective film with adhesive-B1: An acrylic resin adhesive (thickness 20 ⁇ m, storage elastic modulus 0.2 MPa) applied to a PET resin film (thickness 38 ⁇ m) (manufactured by Fujimori Kogyo).
- Polarizing plate-B1 manufactured by Sumitomo Chemical Co., Ltd., SRCZ4QJ-HCB, thickness 60 ⁇ m, polarizing plate configuration: TAC / PVA / COP, polyvinyl alcohol adhesive.
- Protective film with adhesive-C1 A PET resin film (thickness 38 ⁇ m) coated with an acrylic resin adhesive (thickness 25 ⁇ m, storage elastic modulus 0.2 MPa) (manufactured by Fujimori Kogyo).
- Polarizing plate-C1 manufactured by Sumitomo Chemical Co., Ltd., SRW062A, thickness 100 ⁇ m, polarizing plate constitution: TAC / PVA / COP, polyvinyl alcohol adhesive.
- the storage elastic modulus at 25 ° C. of the acrylic pressure-sensitive adhesive used for the first pressure-sensitive adhesive layer was 0.2 MPa.
- the storage elastic modulus at 50 ° C. of the acrylic pressure-sensitive adhesive used for the second pressure-sensitive adhesive layer was 0.5 MPa.
- the storage elastic modulus at 50 ° C. of the acrylic pressure-sensitive adhesive used for the third pressure-sensitive adhesive layer was 0.4 MPa.
- the storage modulus ( ⁇ ) of the pressure-sensitive adhesive is a dynamic viscoelasticity measuring device (Dynamic Analyzer RDA II: manufactured by Reometric Co., Ltd.).
- the initial strain was set to 1 N by the torsional shear method with a frequency of 1 Hz, and the measurement was performed under the conditions of a temperature of 23 ° C. or 50 ° C. (see the description of paragraph [0164] of WO2009 / 119435 A1).
- Example A1 Production of optical laminate A-1
- the precursor of the optical laminate A is cut into a size of 10.6 cm ⁇ 9.1 cm, and a pseudo foreign material having a diameter of 100 ⁇ m is formed between the protective film and the first pressure-sensitive adhesive layer in the precursor of the optical laminate A. Introduced to produce artificial bubbles.
- the optical laminate A precursor was pressurized for 5 minutes under an environment of pressure 0.2 MPaG and temperature of room temperature 25 ° C. using an autoclave (manufactured by Kurihara Seisakusho, model number YK-750L), and then over 10 minutes.
- an optical laminate A-1 was produced through a precursor post-treatment step including reducing the pressure in the autoclave to normal pressure (0) MPaG.
- the said pressure and temperature read the value (gauge pressure) currently displayed on the autoclave.
- the gas in the autoclave was air.
- the bubble size in the precursor and the dot-like bubble size have sides in the optical axis direction of the polarizing plate and the direction orthogonal thereto, and
- the length of the side in the optical axis direction of the polarizing plate is a, and the direction orthogonal to the optical axis direction of the polarizing plate
- b is the length of the side of the following expression (1)
- ⁇ AC front (a + b) / 2 (1) I asked for it.
- the optical layered body that is, the dot-like bubble size after the bubble removal step ( after ⁇ AC) was measured in the same manner as described above.
- the measurement of these bubble sizes was performed several times, and the average value was described in the table
- FIG.4 (b) is a photograph which shows the state around the foreign material shown to Fig.4 (a) after passing through the manufacturing method of this invention.
- Bubble size average change rate ⁇ (after ⁇ AC before - ⁇ AC) / ⁇ AC before Calculated according to In this specification, the higher the bubble size change rate, the more efficiently the bubble size can be reduced and the bubble can be removed.
- the average bubble size change rate results for the examples are shown in Table 1.
- the value of the bubble reduction rate is 100%, it means that the bubble size is reduced in all the observed bubbles.
- the ratio of bubbles with a bubble size reduced by 10% or more was calculated and found to be 100%.
- Table 1 shows the bubble reduction rate indicating the ratio of disappearance of bubbles, the maximum value, the minimum value, and the average value of the bubble size after pressurization.
- Example A2 to A6 Using the optical laminate precursor A produced in Example A1, the optical laminate A was used under the same conditions as in Example A1 except for the conditions of pressure, temperature, pressurization time, and decompression time described in Table 1. -2 to A-6 were produced. The various evaluation results in these examples are shown in Table 1. For example, in Example A3, when the ratio of bubbles with a bubble size reduced by 10% or more was calculated for a plurality of samples, the maximum value of the ratio was 100%.
- Comparative Examples A1 to A2 Using the optical laminate precursor A produced in Example A1, the optical laminate AC1 was produced under the conditions of, for example, a pressure of 0.5 MPaG, a temperature of 70 ° C., a pressurization time of 5 minutes, and a decompression time of 20 minutes.
- Table 1 shows various evaluation results in the comparative example. In the table, “bubble generation” means that a new bubble is generated during the processing in the autoclave, and the bubble size cannot be measured.
- the long side change amount and the short side change amount were calculated.
- a two-dimensional measuring instrument Cho Denki Keiki Seisakusho, GS-8550
- L AC long side length in the obtained optical laminate from (after L AC)
- W AC short side length in the obtained optical laminate from (after W AC)
- the sign of the obtained result is represented by minus, it means that contraction has occurred in the long side direction.
- Table 2 the size of the precursor of the optical layered body was 106.41 mm ⁇ 60.92 mm.
- the amount of warpage in the precursor of the optical laminate is such that the precursor of the optical laminate is placed on a horizontal glass panel so that the direction of curl is as shown in FIG. 3, and the horizontal plane in the center of the plane (the horizontal plane of the glass panel) The relative height of the bulge at the end is measured.
- the amount of warpage was measured using a metal scale.
- the amount of warpage of the optical laminated body is determined by, for example, placing the optical laminated body obtained through the manufacturing method according to the present invention on a horizontal glass panel so that the direction of curl is the direction shown in FIG.
- the warpage amount of the optical laminate is significantly smaller than the warpage amount of the precursor. Since an optical laminate having such properties can be obtained, according to the present invention, for example, the amount of warpage of a liquid crystal panel after incorporating a polarizing plate can be reduced. Thereby, it is possible to prevent the display quality from being deteriorated due to the warp of the liquid crystal panel, and it is possible to avoid defects when assembling the liquid crystal display or the like and the casing. On the other hand, for example, when the amount of warping is large as shown in Comparative Example A1, a bonding failure occurs when bonding to a liquid crystal panel or the like. Moreover, when the amount of warpage increases, bubbles are likely to be mixed between the liquid crystal panel and the optical laminate such as a polarizing plate.
- Example B1 Production of optical laminate B1
- the precursor of the optical laminate B is cut into a size of 10.6 cm ⁇ 9.1 cm, and between the protective film and the first pressure-sensitive adhesive layer in the precursor of the optical laminate B, An artificial bubble was produced by introducing a pseudo foreign material having a diameter of 100 ⁇ m.
- An optical laminate B1 was produced in the same manner as in Example A1.
- Examples B2 to B6 Using the precursor of the optical laminate B produced in Example B1, optical laminates B-2 to B-6 were produced under the same conditions as in Example B1 except for the conditions described in Table 4. The various evaluation results in these examples are shown in Table 4.
- Comparative examples B1 and B2 Using the precursor of the optical laminate B produced in Example B1, the optical laminate BC-1 is produced, for example, under the conditions of pressure 0.5 MPaG, temperature 70 ° C., pressurization time 5 minutes, and decompression time 20 minutes. did.
- Table 4 shows various conditions and evaluation results in the comparative example.
- bubble generation means a state where new bubbles are generated during the processing in the autoclave and the bubble size cannot be measured.
- Example B3 obtained by the manufacturing method according to the present invention
- the absorption axis of the polarizer is present in the long side direction of the optical laminate, and the precursor of the optical laminate has a size of 106.41 mm ⁇ 60.92 mm. .
- Table 5 and Table 6 The results are shown in Table 5 and Table 6.
- Example C1 Manufacture of optical laminate C1
- the precursor of optical laminate C is cut into a size of 10.6 cm ⁇ 9.1 cm, and between the protective film and the first pressure-sensitive adhesive layer in the precursor of optical laminate C, An artificial bubble was produced by introducing a pseudo foreign material having a diameter of 100 ⁇ m.
- Optical laminated body C1 was manufactured like the said Example A1.
- Example C1 was manufactured under the conditions of a pressure of 0.5 MPaG, a treatment temperature of 30 ° C., a pressurization time of 5 minutes, and a decompression time of 20 minutes.
- Comparative Examples C1-C2 Using the precursor of the optical laminate C produced in Example C1, the optical laminate CC-1 is produced, for example, under the conditions of pressure 0.5 MPaG, temperature 50 ° C., pressurization time 5 minutes, and decompression time 20 minutes. did. Table 7 shows various conditions and evaluation results in the comparative example. In the table, “bubble generation” means a state where new bubbles are generated during the processing in the autoclave and the bubble size cannot be measured.
- Example C1 and the like obtained by the manufacturing method according to the present invention
- the same evaluation was performed for the comparative example.
- the absorption axis of the polarizer exists in the long side direction of the optical laminate, and the precursor of the optical laminate has a size of 106.41 mm ⁇ 60.92 mm.
- Table 8 and Table 9 The results are shown in Table 8 and Table 9.
- the bubble size that can be generated during the production of the optical laminate can be reduced or removed. Furthermore, the manufacturing method of this invention can suppress the change of the dimension of an optical laminated body, and the change of the amount of curvature. Moreover, if it is a manufacturing method of this invention, a thermal contraction does not occur easily to a polarizing plate, and the change of the dimension of an optical laminated body and the change of the curvature amount can be suppressed.
- the production method of the present invention it is possible to efficiently produce a polarizing plate free from entrapment of bubbles having a size that degrades the quality of the polarizing plate in the pressure-sensitive adhesive layer. As a result, the productivity and yield of the polarizing plate can be increased (the defective rate is decreased). Therefore, the present invention can be widely used in various industries using polarizing plates, such as notebook personal computers, mobile devices such as mobile phones, and large televisions.
Abstract
Description
[1]少なくとも、保護フィルムと、第1の粘着剤層と、偏光板とを有する光学積層体の製造方法であって、
前記保護フィルムと前記第1の粘着剤層と前記偏光板とを貼合せ、光学積層体の前駆体を作製する工程、および、
前記光学積層体の前駆体を、50℃未満の温度、かつ、0.2MPaG以上の雰囲気中に配置する工程、
を含む、光学積層体の製造方法。
[2]前記光学積層体が、さらに機能性フィルムと、第2の粘着剤層とを有する、[1]に記載の光学積層体の製造方法であって、
さらに、前記機能性フィルムと、前記第2の粘着剤層とを貼合せる工程、および
前記第2の粘着剤層を、50℃未満の温度、かつ、0.2MPaG以上の雰囲気中に配置する工程、
を含む、光学積層体の製造方法。
[3]前記光学積層体が、さらに第3の粘着剤層および剥離紙を有する、[1]または[2]に記載の光学積層体の製造方法であって、
さらに、第3の粘着剤層と剥離紙とを貼合せる工程、および
前記第3の粘着剤層を、50℃未満の温度、かつ、0.2MPaG以上の雰囲気中に配置する工程、
を含む、光学積層体の製造方法。
[4]前記光学積層体の厚さが、200μm以下である、[1]~[3]のいずれか1に記載の、光学積層体の製造方法。
[5]前記偏光板の厚さが、10~65μm以下である、[1]~[4]のいずれか1に記載の、光学積層体の製造方法。
[6]保護フィルムの厚さが、100μm以下である、[1]~[5]のいずれか1に記載の、光学積層体の製造方法。
前記保護フィルムと前記第1の粘着剤層と前記偏光板とを貼合せ、光学積層体の前駆体を作製する工程、および、
前記光学積層体の前駆体を、50℃未満の温度、かつ、0.2MPaG以上の雰囲気中に配置する工程(以下、「前駆体の後処理工程」または「第1の粘着剤層を含む前駆体の後処理工程」ともいう)
を含む、光学積層体の製造方法に関する。
本発明の製造方法によれば、第1の粘着剤層の存在する気泡サイズを効果的に縮小でき、気泡を効果的に除去できる。なお、本発明において、圧力単位が「MPaG」で示される場合、その圧力は、特に指定がない限り、ゲージ圧を意味する。
さらに、得られた光学積層体の寸法変化と、反り量の変化量についても抑制できる。
これらの温度範囲および圧力範囲である限り、温度と圧力の組合せは限定されない。例えば、温度が15~30℃である場合、圧力は0.2~0.5MPaGであってもよい。 例えば、温度は、上記範囲に加えて、10~45℃であってもよく、30℃超~50℃未満であってもよく、35℃~45℃あってもよい。
また、加圧雰囲気は、上記範囲に加えて、0.3~0.6MPaG、0.35~0.55MPaGの範囲であってもよい。
例えば、3~30分かけて処理をおこなう。なお、本明細書において、加圧時間とは、特に記載のない限り、加圧の開始から、所定の圧力に達し、その後一定の圧力を保持した時間の合計である。また、圧力を段階的に増加させてもよく、一定の上昇率で圧力を増加させてもよい。
このような条件で減圧を行うことにより、気泡サイズの縮小および気泡除去を効果的に行え、さらに、光学積層体の収縮を予防できる。また、得られた光学積層体の反り量が著しく大きくなることを防ぎ得る。
本明細書において減圧時間とは、特に記載のない限り、減圧の開始から、常圧に達するまでの時間を意味する。減圧を段階的に行ってもよく、一定の変化率で圧力を低下させてもよい。
例えば、光学積層体の製造方法は、保護フィルムと第1の粘着剤層を貼合わせた後に、前駆体の予備処理工程を含み、その後、前駆体の後処理工程を含んでもよい。
第1の粘着剤層と偏光板を貼合わせた後、前駆体の後処理工程を含んでもよい。光学積層体の前駆体を作製する前段階において、前駆体の予備処理工程を含むことにより、さらに効果的に気泡を除去できる。
さらに、前記機能性フィルムと、前記第2の粘着剤層とを貼合せる工程、および
前記第2の粘着剤層を、50℃未満の温度、かつ、0.2MPaG以上の雰囲気中に配置する工程(以下、「第2の粘着剤層を含む前駆体の後処理工程」ともいう)を含む、光学積層体の製造方法を提供する。
本発明の製造方法によれば、少なくとも、第2の粘着剤層の存在する気泡サイズを効果的に縮小でき、気泡を効果的に除去できる。
さらに、得られた光学積層体の寸法変化と、反り量の変化量についても抑制できる。
また、保護フィルムと、第1の粘着剤層と、機能性フィルムと、第2の粘着剤層とを貼合せた後におこなってもよい。
例えば、保護フィルムと、第1の粘着剤層と、機能性フィルムと、第2の粘着剤層とを貼合せ、得られた光学積層体の前駆体を、50℃未満の温度、0.2MPaG以上の雰囲気中に配置し、第2の粘着剤層に存在する気泡を縮小または除去し、次いで、第2の粘着剤層における機能性フィルムとは反対側の面に偏光板を貼合わせ、偏光板を含む、光学積層体の前駆体を50℃未満の温度、0.2MPaG以上の雰囲気中に配置し、第2の粘着剤層に存在する気泡を縮小または除去し、光学積層体を得てもよい。
さらには、保護フィルムと、第1の粘着剤層と、機能性フィルムと、第2の粘着剤層と、偏光板とを貼合せた後に、0.2MPaG以上の雰囲気中に配置し、第2の粘着剤層に存在する気泡を縮小または除去し、光学積層体を得てもよい。
いずれの形態であっても、第2の粘着剤層が、50℃未満の温度、0.2MPaG以上の雰囲気中に配置されることにより、第2の粘着剤層に存在する気泡を、効率的に除去できる。
また、第2の粘着剤層を含む前駆体の後処理工程を単独で行ってもよい。第2の粘着剤層を含む前駆体の後処理工程は、第1の粘着剤層を含む前駆体の後処理工程と共に行う場合、上記前駆体の後処理工程に付される条件に従い行われ得る。また、第1の粘着剤層を含む前駆体の後処理工程と、第2の粘着剤層を含む前駆体の後処理工程とを、それぞれ独立して行う場合、処理温度、圧力等の条件は、同一であってもよく、異なってもよい。施された第1および第2の粘着剤層の種類、厚さ等により、これらの条件を適宜設定できる。
これらの温度範囲および圧力範囲である限り、温度と圧力の組合せは限定されない。例えば、温度15~30℃であるの場合、圧力は0.2~0.5MPaGであってもよい。
例えば、温度は、上記範囲に加えて、10~45℃であってもよく、30℃超~50℃未満であってもよく、35℃~45℃あってもよい。
また、加圧雰囲気は、上記範囲に加えて、0.3~0.6MPaG、0.35~0.55MPaGの範囲であってもよい。
このような範囲で減圧を行うことにより、気泡サイズの縮小および気泡の除去を効果的に行え、さらに、光学積層体の収縮を予防できる。また、得られた光学積層体の反り量が著しく大きくなることを防ぎ得る。
さらに、第3の粘着剤層と剥離紙とを貼合せる工程、および
前記第3の粘着剤層を、50℃未満の温度、かつ、0.2MPaG以上の雰囲気中に配置する工程(以下、「第3の粘着剤層を含む前駆体の後処理工程」ともいう)、
を含む、光学積層体の製造方法を提供する。
上記工程を含むことにより、少なくとも、第3の粘着剤層の存在する気泡サイズを効果的に縮小でき、気泡を効果的に除去できる。
さらに、得られた光学積層体の寸法変化と、反り量の変化量についても抑制できる。
また、保護フィルムと、第1の粘着剤層と、機能性フィルムと、第2の粘着剤層と偏光板と第3の粘着剤層とを貼合せた後におこなってもよい。
例えば、保護フィルムと、第1の粘着剤層と、機能性フィルムと、第2の粘着剤層と偏光板と第3の粘着剤層と剥離紙とを貼合せ、得られた光学積層体の前駆体を、50℃未満の温度、0.2MPaG以上の雰囲気中に配置し、上記前駆体の後処理工程を経て、光学積層体を得てもよい。このような場合、本明細書においては、上記「前駆体の後処理工程」に「第3の粘着剤層を含む前駆体の後処理工程」が含まれることになる。
いずれの形態であっても、第3の粘着剤層が、50℃未満の温度、0.2MPaG以上の雰囲気中に配置されることにより、第3の粘着剤層に存在する気泡を、効率的に除去できる。
これらの前駆体の後処理工程をそれぞれ独立して行う場合、処理温度、圧力等の条件は、同一であってもよく、異なってもよい。
さらに、第1の粘着剤層を含む前駆体の後処理工程と、第2の粘着剤層を含む前駆体の後処理工程とを同一工程で行い、第3の粘着剤層を含む前駆体の後処理工程を独立して行う場合、処理温度、圧力等の条件は、両者において同一であってもよく、異なってもよい。施された第1~第3の粘着剤層の種類、厚さ等により、これらの条件を適宜設定できる。
これらの温度範囲および圧力範囲である限り、温度と圧力の組合せは限定されない。例えば、温度15~30℃であるの場合、圧力は0.2~0.5MPaGであってもよい。
例えば、温度は、上記範囲に加えて、10~45℃であってもよく、30℃超~50℃未満であってもよく、35℃~45℃あってもよい。
また、加圧雰囲気は、上記範囲に加えて、0.3~0.6MPaG、0.35~0.55MPaGの範囲であってもよい。
このような範囲で減圧を行うことにより、気泡サイズの縮小および気泡の除去を効果的に行え、さらに、光学積層体の収縮を予防できる。また、得られた光学積層体の反り量が著しく大きくなることを防ぎ得る。
気泡サイズを計算する方法を、図2に基づいて説明する。図2は、本発明の気泡サイズを計算する方法を説明する図であり、(a)は点状の気泡(点状気泡)の大きさを計算する方法を説明する図であり、(b)は斑点状の気泡(斑点状気泡)の大きさを計算する方法を説明する図である。なお、図2の(a)および(b)中に示した矢印Eは、偏光板の光学軸方向を示している。
Φ1 =(a+b)/2 …(1)
から求められる。
Φ2 =(c+d)/2 …(2)
から求められる。
気泡サイズの変化率平均は、例えば、1~70%であり、特に、10~60%である。
また、気泡の縮小および除去に関する評価は、気泡縮小率を算出して評価してもよい(具体的な算出方法は、実施例に記載した)。気泡縮小率の値が100%であると、観察された気泡全てにおいて気泡サイズが縮小したことを意味する。気泡縮小率は、例えば10~100%であり、特に、30~100%である。
さらに、気泡の縮小および除去に関する評価は、気泡サイズが10%以上減少した割合を算出することにより行ってもよい。本発明の製造方法によれば、例えば、気泡サイズが10%以上減少した気泡の割合は、100%となる場合がある。気泡サイズが10%以上減少した気泡の割合は、例えば、20~100%である。
上記評価に代えて、または加えて、当該技術分野において既知の方法により気泡サイズを測定し、評価を行ってもよい。
偏光板3の厚さがこのような範囲であることにより、例えば、液晶ディスプレイの薄型化が可能となる。偏光板3の厚さがこのような範囲であっても、液晶パネルを囲む枠(額縁)の幅を狭くしたもの(狭額縁)に貼り付ける光学フィルムとして、寸法精度要求の高いフィルム製造することができる。さらに、反り量の抑制により光学フィルムを張り付け後の液晶ディスプレイの反り量を抑えることができる。
なお、本明細書において変化量がマイナスの値を取る場合、光学積層体の前駆体が収縮し、光学積層体が得られたことを意味する。
長辺方向の変化量(以下、長辺変化量と記載する場合もある)、および短辺方向の変化量(以下、短辺変化量と記載する場合もある)が上記範囲内であることにより、光学積層体の著しい収縮が生じておらず、薄型の光学積層体に要求される寸法精度を保つことができる。
寸法変化率長辺=(LAC後-LAC前)/LAC前×100
同様に、短辺方向の寸法変化率(以下、「寸法変化率短辺」と記載する場合もある)は、次式に従い導かれる
寸法変化率短辺=(WAC後-WAC前)/WAC前×100
なお、本明細書において変化量がマイナスの値を取る場合、光学積層体の前駆体が収縮し、光学積層体が得られたことを意味する。
例えば、光学積層体の前駆体を、30℃超~50℃未満、具体的には、35℃~45℃の温度、かつ、0.2MPaG以上、例えば、0.2~0.7MPaGの雰囲気中に20分以下、例えば1分~10分間配置する場合、光学積層体の前駆体の「寸法変化率長辺」は、例えば-0.01~0.01%の範囲であることができ、光学積層体の前駆体の「寸法変化率短辺」は、例えば-0.01~0.01%の範囲であることができる。
例えば、光学積層体の反り量から、光学積層体の前駆体の反り量を差し引いた差から反り量の変化量を求めることにより、光学積層体の反りの大小を評価できる。
具体的には、光学積層体10における反り量は、例えば、図3に示すように、光学積層体10をカールの向きが図3で示す向きとなる様に水平なガラスパネル60に載せ、面内中心部の水平面70(ガラスパネル60の水平面)に対する、端部の盛り上がりの相対高さ(Δhw)を測定したものである。
また、光学積層体の前駆体の反り量は、上記光学積層体と同様に、例えば、本発明に係る製造方法を経て得られた光学積層体の前駆体をカールの向きが図3で示す向きとなる様に水平なガラスパネルに載せ、面内中心部の水平面(ガラスパネルの水平面)に対する、端部の盛り上がりの相対高さを測定したものである。
反り量の変化量は、このようにして求めた光学積層体の反り量から、光学積層体の前駆体の反り量を差し引いた差である。
ここで、反り量の変化量を絶対値で示すと、変化量の絶対値が大きくなるにつれ、光学積層体の反りも大きくなることを意味する。
図3に、参考として、光学積層体の断面図と、反り量の関係とを示す概略図を示す。
例えば、長さ10~13cm、幅6~10cm未満、厚さ60~200μmの光学積層体の場合、反り量の変化量は、-1~+1mmであり得る。
(前駆体A)
粘着剤付保護フィルム-A1:PET樹脂フィルム(厚さ38μm)にアクリル樹脂系粘着剤(厚さ15μm、貯蔵弾性率0.2MPa)を塗布したもの(藤森工業製)。
第2の粘着剤:アクリル樹脂系粘着剤、厚さ15μm、貯蔵弾性率0.5MPa
第3の粘着剤:アクリル樹脂系粘着剤、厚さ20μm、貯蔵弾性率0.4MPa
偏光板-A1:住友化学製、SR024CUT、厚さ20μm、偏光板構成:PVA/COP、ポリビニルアルコール系接着剤
剥離紙:PET樹脂フィルム(厚さ38μm)にシリコン系離型剤を塗布したもの
機能性フィルム:スリーエム社製、輝度向上フィルム、APF-V3-HC、厚さ28μm
(前駆体B)
粘着剤付保護フィルム-B1:PET樹脂フィルム(厚さ38μm)にアクリル樹脂系粘着剤(厚さ20μm、貯蔵弾性率0.2MPa)を塗布したもの(藤森工業製)。
偏光板-B1:住友化学製、SRCZ4QJ-HCB、厚さ60μm、偏光板構成:TAC/PVA/COP、ポリビニルアルコール系接着剤。
(前駆体C)
粘着剤付保護フィルム-C1:PET樹脂フィルム(厚さ38μm)にアクリル樹脂系粘着剤(厚さ25μm、貯蔵弾性率0.2MPa)を塗布したもの(藤森工業製)。
偏光板-C1:住友化学製、SRW062A、厚さ100μm、偏光板構成:TAC/PVA/COP、ポリビニルアルコール系接着剤。
第1の粘着剤層に用いたアクリル系感圧性粘着剤の25℃における貯蔵弾性率は、0.2MPaであった。第2の粘着剤層に用いたアクリル系感圧性粘着剤の50℃における貯蔵弾性率は、0.5MPaであった。第3の粘着剤層に用いたアクリル系感圧性粘着剤の50℃における貯蔵弾性率は、0.4MPaであった。上記粘着剤の貯蔵弾性率(σ)は、測定対象の粘着剤からなる直径8mm×厚さ1mmの円柱状の試験片を作製し、動的粘弾性測定装置(Dynamic Analyzer RDA II:Reometric社製)を用いて、周波数1Hzの捻りせん断法で初期歪み1Nとし、温度23℃または50℃の条件で測定を行った(WO2009/119435 A1の段落〔0164〕の記載を参照)。
光学積層体の前駆体Aの作製
保護フィルムと、第1の粘着剤層と、機能性フィルムと、第2の粘着剤層と、偏光板と、第3の粘着剤層と、剥離紙とを貼合せ、光学積層体Aの前駆体を作製した。得られた光学積層体Aの前駆体における気泡サイズ等の各種物性値を、後述の方法に従い測定した。
光学積層体A-1の製造
光学積層体Aの前駆体を、10.6cm×9.1cmの大きさに裁断し、光学積層体Aの前駆体における保護フィルムと第1の粘着剤層の間に、100μm径の疑似異物を導入し、人工的な気泡を作製した。
次いで、光学積層体Aの前駆体を、オートクレーブ(栗原製作所製、型番YK-750L)を用いて、圧力0.2MPaG、温度常温25℃の環境下で5分間にわたって加圧し、次いで、10分かけて、オートクレーブ内の圧力を、常圧(0)MPaGに減圧することを含む、前駆体の後処理工程を経て、光学積層体A-1を製造した。なお、上記圧力および温度は、オートクレーブに表示されている値(ゲージ圧)を読み取ったものである。また、オートクレーブ内における気体は空気であった。
実施例および比較例における気泡除去処理前の気泡(点状気泡)の大きさを、以下に記載した方法によって測定した。気泡のサイズ測定には、OLYMPUS製の顕微鏡(BX51)を用いて行った。
ΦAC前=(a+b)/2 …(1)
から求めた。
同様に、光学積層体、すなわち気泡除去工程後の点状気泡サイズ(ΦAC後)を、上記と同様にして測定した。なお、これらの気泡サイズの測定を複数回行い、その平均値を表に記載した。
例えば、実施例A3において人工的に作製した気泡を、図4(a)に示す。気泡の中心部分には異物が確認される。また、図4(b)は、本発明の製造方法を経た後の、図4(a)に示した異物周囲の状態を示す写真である。このように、本発明の製造方法によると、前駆体に存在した気泡を効果的に除去できる。
気泡サイズ変化率平均Φは、次式
Φ=(ΦAC前-ΦAC後)/ΦAC前
に従い算出した。本明細書においては、気泡サイズの変化率が高いほど、効率的に気泡サイズの減少および気泡除去を行えたことを意味する。実施例に関する気泡サイズ変化率平均の結果を、表1に示す。
気泡縮小率の評価は、次式
気泡縮小率=気泡縮小した数/評価n数
に従い算出した。換言すると、ΦAC前>ΦAC後となった気泡サンプルの割合を示す評価である。この気泡縮小率の値が100%であると、観察された気泡全てにおいて気泡サイズが縮小したことを意味する。
なお、実施例A1において、気泡サイズが10%以上減少した気泡の割合について算出したところ、100%であった。また、実施例A1において、気泡のサイズを複数回測定したところ、本発明の製造方法を経ることにより、気泡が消失した例もあった。
また、気泡が消失した割合を示す気泡削減率、加圧後の気泡サイズの最大値、最小値および平均値を表1に示す。
上記実施例A1で作製した光学積層体の前駆体Aを用い、表1に記載した圧力、温度、加圧時間、減圧時間の条件以外は、実施例A1と同様の条件で、光学積層体A-2~A-6を作製した。これらの実施例における各種評価結果を表1に示す。なお、例えば、実施例A3において、複数個の試料に対して、気泡サイズが10%以上減少した気泡の割合について算出したところ、上記割合の最高値は100%であった。
上記実施例A1で作製した光学積層体の前駆体Aを用い、例えば、圧力0.5MPaG、温度70℃、加圧時間5分、減圧時間20分の条件で、光学積層体AC1を作製した。比較例における各種評価結果を表1に示す。なお、表中、「気泡湧き出し」とは、オートクレーブ内での処理中に、新たな気泡が発生し、気泡サイズの測定等ができなかった状態を意味する。
例えば、実施例A3で得られた光学積層体A3、および比較例A1で作製した光学積層体AC1について、長辺方向の変化量、短辺方向の変化量、長辺方向の変化率および短辺方向の変化率を測定した。各種変化量および変化率の算出は、以下のようにして行った。また、いずれの積層体においても、偏光子の吸収軸は幅方向に存在した。得られた結果を、表2に示す。
長辺変化量は、得られた光学積層体における長辺長さ(LAC後)から、光学積層体の前駆体における長辺長さ(LAC前)を差し引いた差である。短辺変化量は、得られた光学積層体における短辺長さ(WAC後)から、光学積層体の前駆体における短辺長さ(WAC前)を差し引いた差で示される。得られた結果の符号がマイナスで表される場合、長辺方向に収縮が生じたことを意味する。結果を表2に示す。
なお、実施例および比較例における、光学積層体の前駆体のサイズは106.41mm×60.92mmのものを使用した。
長辺変化率=(LAC後-LAC前)/LAC前×100から算出され、
短辺変化率=(WAC後-WAC前)/WAC前×100から算出される。
結果を表2に示す。
光学積層体の前駆体における反り量は、光学積層体の前駆体をカールの向きが図3で示す向きとなる様に水平なガラスパネルに載せ、面内中心部の水平面(ガラスパネルの水平面)に対する、端部の盛り上がりの相対高さを測定したものである。反り量の測定は、金尺を用いて行った。
また、光学積層体の反り量は、例えば、本発明に係る製造方法を経て得られた光学積層体をカールの向きが図3で示す向きとなる様に水平なガラスパネルに載せ、面内中心部の水平面(ガラスパネルの水平面)に対する、端部の盛り上がりの相対高さを測定したものである。
反り量の変化量は、このようにして求めた光学積層体の反り量から、光学積層体の前駆体の反り量を差し引いた差である。
これらの評価を、実施例A3で得られた光学積層体A3等、および比較例A1で作製した積層体AC1等について行った。結果を、表3に示す。なお、表3中における値も、複数回測定を行い、その平均値を記載したものである。
一方、例えば、比較例A1に示されるように反り量が大きい場合、液晶パネル等との貼り合せ時に、貼り合せ不良が発生してしまう。また、反り量が大きくなると、液晶パネル等と偏光板等の光学積層体との間に気泡混入が生じやすい。
光学積層体の前駆体Bの作製
保護フィルムと、第1の粘着剤層と、偏光板とを貼合せ、光学積層体Bの前駆体を作製した。得られた光学積層体Bの前駆体における気泡サイズ等の各種物性値を、上記方法に従い測定した。
光学積層体B1の製造
光学積層体Bの前駆体を、10.6cm×9.1cmの大きさに裁断し、光学積層体Bの前駆体における保護フィルムと第1の粘着剤層の間に、100μm径の疑似異物を導入し、人工的な気泡を作製した。
上記実施例A1と同様にして、光学積層体B1を製造した。
上記実施例B1で作製した光学積層体Bの前駆体を用い、表4に記載した条件以外は、実施例B1と同様の条件で光学積層体B-2~B-6を作製した。これらの実施例における各種評価結果を表4に示す。
上記実施例B1で作製した光学積層体Bの前駆体を用い、例えば、圧力0.5MPaG、温度70℃、加圧時間5分、減圧時間20分の条件で、光学積層体BC-1を作製した。比較例における各種条件および評価結果を表4に示す。なお、表中、「気泡湧き出し」とは、オートクレーブ内での処理中に、新たな気泡が発生し、気泡サイズの測定ができなかった状態を意味する。
光学積層体の前駆体Cの作製
保護フィルムと、第1の粘着剤層と、偏光板とを貼合せ、光学積層体Cの前駆体を作製した。得られた光学積層体Cの前駆体における気泡サイズ等の各種物性値を、上記方法に従い測定した。
光学積層体C1の製造
光学積層体Cの前駆体を、10.6cm×9.1cmの大きさに裁断し、光学積層体Cの前駆体における保護フィルムと第1の粘着剤層の間に、100μm径の疑似異物を導入し、人工的な気泡を作製した。
上記実施例A1と同様にして、光学積層体C1を製造した。実施例C1は、圧力0.5MPaG、処理温度30℃、加圧時間5分、減圧時間20分の条件で製造した。
上記実施例C1で作製した光学積層体Cの前駆体を用い、表7に記載した条件を用いて、実施例C1と同様にして光学積層体C2~C3を作製した。これらの実施例における各種評価結果を表7に示す。
上記実施例C1で作製した光学積層体Cの前駆体を用い、例えば、圧力0.5MPaG、温度50℃、加圧時間5分、減圧時間20分の条件で、光学積層体CC-1を作製した。比較例における各種条件および評価結果を表7に示す。なお、表中、「気泡湧き出し」とは、オートクレーブ内での処理中に、新たな気泡が発生し、気泡サイズの測定ができなかった状態を意味する。
1a 第1の粘着剤層
1b 第2の粘着剤層
1c 第3粘着剤層
2 保護フィルム
3 偏光板
4 機能性フィルム
5 剥離紙
10 光学積層体
60 ガラスパネル
70 面内中心部の水平面
Claims (6)
- 少なくとも、保護フィルムと、第1の粘着剤層と、偏光板とを有する光学積層体の製造方法であって、
前記保護フィルムと前記第1の粘着剤層と前記偏光板とを貼合せ、光学積層体の前駆体を作製する工程、および、
前記光学積層体の前駆体を、50℃未満の温度、かつ、0.2MPaG以上の雰囲気中に配置する工程、
を含む、光学積層体の製造方法。 - 前記光学積層体が、さらに機能性フィルムと、第2の粘着剤層とを有する、請求項1に記載の光学積層体の製造方法であって、
さらに、前記機能性フィルムと、前記第2の粘着剤層とを貼合せる工程、および
前記第2の粘着剤層を、50℃未満の温度、かつ、0.2MPaG以上の雰囲気中に配置する工程、
を含む、光学積層体の製造方法。 - 前記光学積層体が、さらに第3の粘着剤層および剥離紙を有する、請求項1または2に記載の光学積層体の製造方法であって、
さらに、第3の粘着剤層と剥離紙とを貼合せる工程、および
前記第3の粘着剤層を、50℃未満の温度、かつ、0.2MPaG以上の雰囲気中に配置する工程、
を含む、光学積層体の製造方法。 - 前記光学積層体の厚さが、200μm以下である、請求項1~3のいずれか1項に記載の、光学積層体の製造方法。
- 前記偏光板の厚さが、10~65μmである、請求項1~4のいずれか1項に記載の、光学積層体の製造方法。
- 前記保護フィルムの厚さが、100μm以下である、請求項1~5のいずれか1項に記載の、光学積層体の製造方法。
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JP2009244486A (ja) * | 2008-03-31 | 2009-10-22 | Toagosei Co Ltd | 位相差一体型複合偏光板及びそれを用いた画像表示装置 |
JP2010191203A (ja) * | 2009-02-18 | 2010-09-02 | Sumitomo Chemical Co Ltd | 偏光板の製造方法 |
JP2012226000A (ja) * | 2011-04-15 | 2012-11-15 | Seiko Epson Corp | 光学素子、投射型映像装置及び光学素子の製造方法 |
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JP2009244486A (ja) * | 2008-03-31 | 2009-10-22 | Toagosei Co Ltd | 位相差一体型複合偏光板及びそれを用いた画像表示装置 |
JP2010191203A (ja) * | 2009-02-18 | 2010-09-02 | Sumitomo Chemical Co Ltd | 偏光板の製造方法 |
JP2012226000A (ja) * | 2011-04-15 | 2012-11-15 | Seiko Epson Corp | 光学素子、投射型映像装置及び光学素子の製造方法 |
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