Method for producing pressure-sensitive adhesive sheet, method for producing optical film with pressure-sensitive adhesive sheet, and method for producing image display device

Abstract

To provide a novel production method suitable for efficiently producing a pressure-sensitive adhesive sheet.SOLUTION: The production method according to the present invention for an adhesive sheet 1 comprises: step A in which a coating layer 12 comprising a photocurable composition is irradiated with light A from a light-emitting diode 34; and step B in which after the step A, the coating layer 12 is irradiated with light B. The light A has a peak wavelength of 325 nm to 350 nm. The illuminance LB of the light B emitted to the coating layer 14 is greater than the illuminance LA of the light A emitted to the coating layer 14. The production method according to the present invention for an optical film 21 with an adhesive sheet includes placing an optical film 2 on an exposed surface 18 of the adhesive sheet 1 formed by this production method to form the optical film 21 with an adhesive sheet.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing a pressure-sensitive adhesive sheet, a method for producing an optical film with a pressure-sensitive adhesive sheet, and a method for producing an image display device. [Background technology]

[0002] Various image display devices, such as liquid crystal display devices and electroluminescence (EL) display devices, generally include an optical laminate including an optical film such as a polarizing film and an adhesive sheet. An adhesive sheet is usually used for bonding between the optical films included in the optical laminate and for bonding between the optical laminate and an image display panel. A typical adhesive sheet is a sheet obtained by polymerizing and crosslinking a monomer group including an acrylic monomer, a silicone monomer, and the like to harden the monomer group.

[0003] Patent Document 1 discloses an example of a pressure-sensitive adhesive sheet, which is produced by irradiating a coating layer of a pressure-sensitive adhesive composition disposed between two release liners with light. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6688054 Summary of the Invention [Problem to be solved by the invention]

[0005] A typical adhesive sheet is manufactured, for example, by the following thermosetting method. First, a crosslinking agent or the like is added to a polymer produced by polymerizing a polymerizable monomer in an organic solvent to prepare an adhesive composition. This adhesive composition is applied to a substrate such as a release liner, and the organic solvent is removed by heating to form a sheet. If necessary, heat aging is performed to complete crosslinking, and an adhesive sheet can be manufactured. In this manufacturing process, a large amount of fuel such as LNG needs to be burned in order to generate the thermal energy required for the thermal removal of the solvent and for heat aging. In addition, if the organic solvent removed by heating is directly released into the atmosphere, it may have a significant adverse effect on the surrounding environment. Therefore, the organic solvent is often burned in a deodorizing furnace or the like before being released. In this case, not only is additional fuel required for combustion in the deodorizing furnace, but the organic solvent itself is also converted into CO2 by combustion and released into the atmosphere, resulting in a manufacturing process with extremely large CO2 emissions.

[0006] In recent years, climate change caused by greenhouse gases has become an urgent issue, and governments around the world have set numerical targets to reduce CO2 emissions. In the manufacture of adhesive sheets, too, there is a demand to select manufacturing processes that do not use organic solvents and that have low CO2 emissions.

[0007] According to a method of producing an adhesive sheet using light (photocuring method), the amount of energy required to form the adhesive sheet and CO2 emissions can be reduced compared to the above-mentioned heat curing method. In the photocuring method, for example, a black light source is used (Patent Document 1). However, according to the study by the present inventors, there is room for improvement in the conventional photocuring method from the viewpoint of efficiently producing an adhesive sheet.

[0008] Therefore, an object of the present invention is to provide a new production method suitable for efficiently producing a pressure-sensitive adhesive sheet. [Means for solving the problem]

[0009] The present invention relates to A step A of irradiating a coating layer containing a photocurable composition with light A from a light emitting diode; After the step A, a step B of irradiating the coating layer with light B; Including, The light A has a peak wavelength of 325 nm to 350 nm, The method for producing a pressure-sensitive adhesive sheet is provided, wherein an illuminance LB of the light B irradiated to the coating layer is greater than an illuminance LA of the light A irradiated to the coating layer.

[0010] Further, the present invention relates to The present invention provides a method for producing an optical film with a pressure-sensitive adhesive sheet, the method comprising: forming an optical film with a pressure-sensitive adhesive sheet by disposing an optical film on an exposed surface of the pressure-sensitive adhesive sheet formed by the above-described production method.

[0011] Further, the present invention relates to The present invention also provides a method for producing an image display device, which comprises bonding an optical film with a pressure-sensitive adhesive sheet formed by the above-mentioned production method to an image display panel to form an image display device. Effect of the Invention

[0012] According to the present invention, a new production method suitable for efficiently producing a pressure-sensitive adhesive sheet can be provided. [Brief description of the drawings]

[0013] [Figure 1] 1A to 1C are schematic diagrams illustrating an example of a method for producing a pressure-sensitive adhesive sheet of the present invention. [Diagram 2] 1A to 1C are schematic diagrams illustrating an example of a method for producing a pressure-sensitive adhesive sheet of the present invention. [Diagram 3] 1A to 1C are schematic diagrams illustrating an example of a method for producing a pressure-sensitive adhesive sheet of the present invention. [Figure 4] FIG. 2 is a schematic diagram for explaining an example of a method for producing an optical film with a pressure-sensitive adhesive sheet of the present invention. [Diagram 5] FIG. 2 is a schematic diagram for explaining an example of a method for producing an optical film with a pressure-sensitive adhesive sheet of the present invention. [Figure 6] FIG. 2 is a schematic diagram for explaining an example of a method for producing an optical film with a pressure-sensitive adhesive sheet of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] A method for producing a pressure-sensitive adhesive sheet according to a first aspect of the present invention includes the steps of: A step A of irradiating a coating layer containing a photocurable composition with light A from a light emitting diode; After the step A, a step B of irradiating the coating layer with light B; Including, The light A has a peak wavelength of 325 nm to 350 nm, An illuminance LB of the light B irradiated to the coating layer is greater than an illuminance LA of the light A irradiated to the coating layer.

[0015] In a second aspect of the present invention, for example, in the production method according to the first aspect, the peak wavelength is 340±10 nm.

[0016] In a third aspect of the present invention, for example, in the manufacturing method according to the first or second aspect, in the step A, the light A is irradiated onto a laminate including a base sheet, the coating layer, and a release liner in this order.

[0017] In a fourth aspect of the present invention, for example, in the manufacturing method according to any one of the first to third aspects, the illuminance LA is 2.0 to 30 mW / cm 2 It is.

[0018] In a fifth aspect of the present invention, for example, in the manufacturing method according to any one of the first to fourth aspects, a ratio of the illuminance LB to the illuminance LA is 1.2-10.

[0019] In a sixth aspect of the present invention, for example, in the manufacturing method according to any one of the first to fifth aspects, the light source of the light B is at least one selected from the group consisting of a light emitting diode, a metal halide lamp, and a black light source.

[0020] In a seventh aspect of the present invention, for example, the manufacturing method according to any one of the first to sixth aspects further includes, after the step B, a step C of irradiating the coating layer with light C, and the illuminance LC of the light C irradiated to the coating layer is greater than the illuminance LB.

[0021] In an eighth aspect of the present invention, for example, in the production method according to any one of the first to seventh aspects, the photocurable composition contains a monomer group including a (meth)acrylic monomer and / or a partial polymer of the monomer group.

[0022] In a ninth embodiment of the present invention, for example, in the production method according to the eighth embodiment, the polymerization rate of the monomer group at the time when the step A is completed is 50% or more.

[0023] In a tenth aspect of the present invention, for example, in the production method according to the eighth or ninth aspect, the polymerization rate of the monomer group in the pressure-sensitive adhesive sheet is 95% or more.

[0024] In an eleventh aspect of the present invention, for example, in the production method according to any one of the eighth to tenth aspects, the photocurable composition contains a photopolymerization initiator, and the amount of the photopolymerization initiator mixed is 1.0 part by weight or less with respect to 100 parts by weight in total of the monomer group and the partially polymerized product.

[0025] In a twelfth aspect of the present invention, for example, in the production method according to any one of the first to eleventh aspects, the content of the solvent in the photocurable composition is 5% by weight or less.

[0026] A method for producing an optical film with a pressure-sensitive adhesive sheet according to a thirteenth aspect of the present invention comprises the steps of: The method includes forming an optical film with a pressure-sensitive adhesive sheet by disposing an optical film on an exposed surface of the pressure-sensitive adhesive sheet formed by the manufacturing method according to any one of the first to twelfth aspects.

[0027] In a fourteenth aspect of the present invention, for example, in the production method according to the thirteenth aspect, the optical film includes at least one film selected from the group consisting of a polarizing film and a retardation film.

[0028] A method for producing an image display device according to a fifteenth aspect of the present invention includes the steps of: The method includes bonding an optical film with a pressure-sensitive adhesive sheet formed by the manufacturing method according to the thirteenth or fourteenth aspect to an image display panel to form an image display device.

[0029] The present invention will be described in detail below, but the present invention is not limited to the following embodiments and can be modified in any manner without departing from the gist of the present invention.

[0030] [Embodiment of the method for producing the pressure-sensitive adhesive sheet] 1, the method for producing a pressure-sensitive adhesive sheet 1 of the present embodiment includes step A of irradiating a coating layer 12 containing a photocurable composition with light A from a light-emitting diode (LED) 34, and step B of irradiating the coating layer 12 with light B after step A. In step A, the light A has a peak wavelength of 325 nm to 350 nm. In step B, the illuminance LB of the light B irradiated to the coating layer 12 is greater than the illuminance LA of the light A irradiated to the coating layer 12 in step A.

[0031] In the manufacturing method of the present embodiment, steps A and B are performed, which tends to increase the polymerization rate of the monomer group in the produced adhesive sheet 1. Steps A and B also make it possible to produce the adhesive sheet 1 in a relatively short time. In this way, the manufacturing method of the present embodiment is suitable for efficiently producing the adhesive sheet 1.

[0032] Specifically, the manufacturing method of this embodiment can be carried out by the following method. First, a laminate (first laminate) 10 is prepared, which includes a base sheet 11, a coating layer 12 containing a photocurable composition, and a release liner 13 in this order. The first laminate 10 is irradiated with light A (step A). ​​Step A is the first light irradiation step performed on the first laminate 10. Furthermore, after step A, the first laminate 10 is irradiated with light B (step B).

[0033] The manufacturing method of this embodiment may further include a step C of irradiating the first laminate 10 (specifically, the coating layer 12) with light C after step B. In this case, the illuminance LC of the light C irradiated to the first laminate 10 (specifically, the coating layer 12) is adjusted to a value greater than the illuminance LB. In this manner, in the manufacturing method of this embodiment, the first laminate 10 (specifically, the coating layer 12) may be irradiated with light by increasing the illuminance stepwise.

[0034] By carrying out steps A and B (and in some cases steps A and C), coating layer 12 is cured and adhesive sheet 1 is formed. The formed adhesive sheet 1 is sandwiched between base sheet 11 and release liner 13 until release liner 13 is peeled off, and constitutes a part of second laminate 17. By peeling release liner 13 from second laminate 17, third laminate 15 including base sheet 11 and adhesive sheet 1 is obtained. In third laminate 15, the surface of adhesive sheet 1 is exposed to the outside.

[0035] (Process A) In step A, irradiation with light A is typically performed from the side of the base sheet 11. At this time, light A penetrates the base sheet 11 to reach the coating layer 12 and initiates curing of the coating layer 12. However, irradiation with light A may also be performed from the side of the release liner 13, or from both the side of the release liner 13 and the side of the base sheet 11.

[0036] As described above, the peak wavelength of the light A irradiated to the first laminate 10 (specifically, the coating layer 12) is 325 nm to 350 nm. The peak wavelength of the light A is preferably 340±10 nm (330 nm to 350 nm), may be 340±5 nm (335 nm to 345 nm), may be 340±2 nm (338 nm to 342 nm), or may be 340 nm. The peak wavelength means a wavelength at which the intensity is a maximum value in a spectrum showing the relationship between the wavelength and the intensity of the light A. The light A may further have a peak wavelength in a wavelength range other than 325 nm to 350 nm, but preferably does not have one.

[0037] The illuminance LA of the light A irradiated onto the first laminate 10 (specifically, the coating layer 12) is, for example, 2.0 to 30 mW / cm 2 The illuminance LA of light A is 2.0 mW / cm 2 By setting the illuminance LA of the light A to 30 mW / cm or more, the coating layer 12 tends to be uniformly cured. 2 When the illuminance LA of the light A is 30 mW / cm or less, the cleavage rate of the photopolymerization initiator contained in the photocurable composition can be appropriately adjusted, and the polymerization rate of the monomer group tends to increase. 2 When the thickness is less than 100 nm, rapid heating of coating layer 12 is suppressed, and there is a tendency for defects in the appearance of pressure-sensitive adhesive sheet 1 to be less likely to occur. When light A is irradiated from both the release liner 13 and base sheet 11 sides, the sum of the illuminance LA of light A from the release liner 13 side and the illuminance LA of light A from the base sheet 11 side is, for example, 2.0 to 30 mW / cm 2 is adjusted to.

[0038] The illuminance LA of light A is preferably 2.5 mW / cm 2 More than 3.0 mW / cm 2 More than 3.5mW / cm 2 More than 4.0mW / cm 2 More than 5.0mW / cm 2 More than 6.0mW / cm 2 More than 7.0mW / cm 2 More than 8.0mW / cm 2 or more, and even 9.0mW / cm2 The upper limit of the illuminance LA of the light A is, for example, 25 mW / cm 2 Less than 20mW / cm 2 Below, 15mW / cm 2 Below 10mW / cm 2 The illuminance LA of the light A may be 6.0 to 10 mW / cm 2 It is preferable that the illuminance LA of the light A be adjusted not only by controlling the LED 34 itself, but also by changing the distance between the LED 34 and the first stack 10.

[0039] The time for irradiating the first laminate 10 (specifically, the coating layer 12) with the light A is not particularly limited, and may be, for example, 10 to 500 seconds, and may be 30 seconds or more, 60 seconds or more, or even 100 seconds or more. The upper limit of the time for irradiating the light A is, for example, 300 seconds or less. The irradiation with the light A may be continuous or intermittent.

[0040] The integrated light amount of the light A on the first laminate 10 (specifically the coating layer 12) is, for example, 25 mJ / cm 2 More than 100 mJ / cm 2 More than 300mJ / cm 2 More than 500mJ / cm 2 or more, even 800mJ / cm 2 The upper limit of the integrated light amount of the light A is not particularly limited, and may be, for example, 10,000 mJ / cm. 2 Less than 5000mJ / cm 2 Below, 3000mJ / cm 2 Below that, even 1000mJ / cm 2 The integrated light amount of the light A may be 500 to 1000 mJ / cm 2 It is preferable that:

[0041] While the first laminate 10 (specifically, coating layer 12) is being irradiated with light A, the temperature of coating layer 12 is maintained at, for example, 50° C. or lower, preferably 10° C. to 30° C. In this case, the curing speed of coating layer 12 is appropriately adjusted, and the number average molecular weight and weight average molecular weight of the polymer contained in pressure-sensitive adhesive sheet 1 tend to increase.

[0042] In step A, the first laminate 10 (specifically, the coating layer 12) may be irradiated with light A in an atmosphere with a reduced oxygen concentration compared to the air (oxygen concentration 20.9 vol%). In this case, the curing of the coating layer 12 is less likely to be inhibited by oxygen, and the number average molecular weight and weight average molecular weight of the polymer contained in the adhesive sheet 1 tend to increase. The irradiation with light A may be performed in an atmosphere with an oxygen concentration of 20 vol% or less, 10 vol% or less, 1 vol% or less, 1000 volppm or less, or even 500 volppm or less. The irradiation with light A may be performed in an atmosphere that is substantially free of oxygen. The atmosphere with a reduced oxygen concentration contains, for example, an inert gas such as argon or nitrogen, and is typically an inert gas atmosphere.

[0043] As described above, in step A, light A from the LED 34 is used. This tends to result in a higher polymerization rate of the monomer group in the formed adhesive sheet 1 compared to, for example, a case in which a black light source is used in step A or a case in which an LED that emits light with a peak wavelength of about 365 nm is used in step A. Furthermore, by using light A from the LED 34 in step A, the amount of remaining photopolymerization initiator in the formed adhesive sheet 1 also tends to decrease.

[0044] In addition, LEDs tend to have a longer light source life as well as easier illuminance adjustment compared to black light sources. LEDs are superior in terms of reducing environmental impact compared to black light sources using mercury. Furthermore, according to the inventors' study, LEDs that emit light A with a peak wavelength of 325 nm to 350 nm tend to generate less heat and to control the temperature of the coating layer 12 more easily compared to LEDs that emit light with a peak wavelength of about 365 nm. Light 14 with a peak wavelength of 325 nm to 350 nm also tends to be more compatible with the absorption wavelength of the photopolymerization initiator compared to light with a peak wavelength of about 365 nm. In addition, as far as the inventors know, there have been no reports of adhesive sheets being produced using LEDs that emit light with a peak wavelength of 325 nm to 350 nm.

[0045] (Process B) In step B, irradiation with light B is typically performed from the side of the base sheet 11. At this time, light B passes through the base sheet 11 to reach the coating layer 12 and promotes the curing of the coating layer 12. However, irradiation with light B may be performed from the side of the release liner 13, or from both the side of the release liner 13 and the side of the base sheet 11.

[0046] The light B is, for example, visible light or ultraviolet light having a wavelength shorter than 450 nm. The light B may be light obtained by cutting short-wavelength light having a wavelength of 300 nm or less using a filter or the like. Examples of the light source 35a for the light B include an LED, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an extra-high-pressure mercury lamp, a metal halide lamp, a xenon lamp, a microwave-excited mercury lamp, a black light source, a chemical lamp, a germicidal lamp, a low-pressure discharge mercury lamp, and an excimer laser. The light source 35a for the light B is preferably at least one selected from the group consisting of an LED, a metal halide lamp, and a black light source. As an example, the light source 35a may be an LED that irradiates light having a peak wavelength of 300 to 450 nm, or an LED that irradiates light having a peak wavelength of 325 nm to 350 nm. An example of this LED is the above-mentioned LED 34. The light source 35a may be an LED that irradiates light having a peak wavelength of 365±10 nm, depending on the circumstances.

[0047] As described above, the illuminance LB of the light B irradiated onto the first laminate 10 (specifically, the coating layer 12) is greater than the illuminance LA of the light A. This allows the coating layer 12 to be cured in a shorter time than when only the step A is performed. The illuminance LB of the light B is, for example, 5.0 to 80 mW / cm 2 In addition, when light B is irradiated from both the release liner 13 and the base sheet 11 sides, the total value of the illuminance LB of light B from the release liner 13 side and the illuminance LB of light B from the base sheet 11 side is, for example, 5.0 to 80 mW / cm 2 is adjusted to.

[0048] The illuminance LB of light B is preferably 8.0 mW / cm2 More than 10 mW / cm 2 More than 13mW / cm 2 More than 15mW / cm 2 More than 18mW / cm 2 or more, even 20mW / cm 2 The upper limit of the illuminance LB of the light B is, for example, 70 mW / cm 2 Less than 60mW / cm 2 Below, 50mW / cm 2 Below, 45mW / cm 2 Below 40mW / cm 2 The illuminance LB of the light B can be adjusted not only by controlling the light source 35a itself, but also by changing the distance between the light source 35a and the first stack 10.

[0049] The ratio LB / LA of the illuminance LB of light B to the illuminance LA of light A is not particularly limited and may be, for example, 1.2 to 10, and may be 8.0 or less, 6.0 or less, 5.0 or less, 4.0 or less, 3.0 or less, or even 2.5 or less. The lower limit of the ratio LB / LA may be 1.5 or more, 1.8 or more, or even 2.0 or more.

[0050] The time for irradiating the first laminate 10 (specifically, the coating layer 12) with the light B is not particularly limited, and may be, for example, 10 to 500 seconds, and may be 30 seconds or more, 60 seconds or more, or even 100 seconds or more. The upper limit of the time for irradiating the light B is, for example, 300 seconds or less. The irradiation of the light B may be continuous or intermittent.

[0051] The integrated light amount of the light B on the first laminate 10 (specifically, the coating layer 12) is, for example, 50 mJ / cm 2 More than 100 mJ / cm 2 More than 300mJ / cm 2 More than 500mJ / cm 2 More than 800mJ / cm 2 or even 1000mJ / cm 2 The upper limit of the integrated light amount of light B is not particularly limited, and may be, for example, 10,000 mJ / cm. 2Less than 5000mJ / cm 2 Below 3000mJ / cm 2 It may be the following.

[0052] The temperature of the coating layer 12 and the surrounding atmosphere while the first laminate 10 (specifically, the coating layer 12) is irradiated with the light B may be the conditions described above for the step A. The step B is preferably performed within 30 seconds after the end of the step A, and particularly preferably performed immediately after the end of the step A.

[0053] (Process C) In step C, irradiation with light C is typically performed from the side of the base sheet 11. At this time, light C penetrates the base sheet 11 to reach the coating layer 12 and promotes the curing of the coating layer 12. However, irradiation with light C may be performed from the side of the release liner 13, or from both the side of the release liner 13 and the side of the base sheet 11.

[0054] The light C is, for example, visible light or ultraviolet light having a wavelength shorter than 450 nm. The light C may be light obtained by cutting short-wavelength light having a wavelength of 300 nm or less with a filter or the like. Examples of the light source 35b of the light C include those described above for the light source 35a of the light B, and more specifically, LED, low-pressure mercury lamp, medium-pressure mercury lamp, high-pressure mercury lamp, extra-high-pressure mercury lamp, metal halide lamp, xenon lamp, microwave-excited mercury lamp, black light source, chemical lamp, germicidal lamp, low-pressure discharge mercury lamp, excimer laser, and the like. The light source 35b of the light C is preferably at least one selected from the group consisting of LED, metal halide lamp, and black light source. As an example, the light source 35b may be an LED that irradiates light having a peak wavelength of 300 to 450 nm, or may be an LED that irradiates light having a peak wavelength of 325 nm to 350 nm. An example of this LED is the above-mentioned LED 34. In some cases, the light source 35b may be an LED that emits light with a peak wavelength of 365±10 nm.

[0055] As described above, the illuminance LC of the light C irradiated to the first laminate 10 (specifically, the coating layer 12) is greater than the illuminance LB of the light B. By carrying out steps A to C, the coating layer 12 can be cured in a shorter time. The illuminance LC of the light C is, for example, 10 to 100 mW / cm. 2 In addition, when light C is irradiated from both the release liner 13 and the base sheet 11 sides, the total value of the illuminance LC of light C from the release liner 13 side and the illuminance LC of light C from the base sheet 11 side is, for example, 10 to 100 mW / cm 2 is adjusted to.

[0056] The illuminance LC of light C is preferably 13 mW / cm 2 More than 15mW / cm 2 More than 20mW / cm 2 or more, even 30mW / cm 2 The upper limit of the illuminance LC of the light C is, for example, 80 mW / cm 2 Less than 70mW / cm 2 Below, 60mW / cm 2 Below, 50mW / cm 2 Below 40mW / cm 2 The illuminance LC of the light C can be adjusted not only by controlling the light source 35b itself, but also by changing the distance between the light source 35b and the first stack 10.

[0057] The ratio LC / LB of the illuminance LC of light C to the illuminance LB of light B is not particularly limited and may be, for example, 1.2 to 10, and may be 8.0 or less, 6.0 or less, 5.0 or less, 4.0 or less, 3.0 or less, or even 2.5 or less. The lower limit of the ratio LC / LB may be 1.5 or more, 1.8 or more, or even 2.0 or more.

[0058] The time for irradiating the first laminate 10 (specifically, the coating layer 12) with the light C is not particularly limited, and may be, for example, 10 to 500 seconds, and may be 30 seconds or more, 60 seconds or more, or even 100 seconds or more. The upper limit of the time for irradiating the light C is, for example, 300 seconds or less. The irradiation with the light C may be continuous or intermittent.

[0059] The integrated amount of light C applied to the first laminate 10 (specifically, the coating layer 12) is, for example, 100 mJ / cm 2 More than 300 mJ / cm 2 More than 500mJ / cm 2 More than 800mJ / cm 2 or even 1000mJ / cm 2 The upper limit of the integrated light amount of the light C is not particularly limited, and may be, for example, 10,000 mJ / cm 2 Less than 5000mJ / cm 2 Below 3000mJ / cm 2 It may be the following.

[0060] The temperature of the coating layer 12 and the surrounding atmosphere while the first laminate 10 (specifically, the coating layer 12) is irradiated with the light C may be the conditions described above for the step A. The step C is preferably performed within 30 seconds after the end of the step B, and particularly preferably performed immediately after the end of the step B.

[0061] In steps A and B (and possibly steps A and C), the total time for irradiating the first laminate 10 (specifically, the coating layer 12) with light (total irradiation time) is not particularly limited and may be, for example, 20 seconds to 1000 seconds, 60 seconds or more, 100 seconds or more, 150 seconds or more, 200 seconds or more, or even 250 seconds or more. The upper limit of the total irradiation time is, for example, 800 seconds or less, and may be 600 seconds or less, 500 seconds or less, or even 400 seconds or less.

[0062] (Heating process) The manufacturing method of this embodiment may further include a heating step of heating the adhesive sheet 1 after steps A and B (and in some cases steps A to C). As an example, the heating step is performed on a third laminate 15 including the base sheet 11 and the adhesive sheet 1. The heating step promotes drying and curing of the adhesive sheet 1, and tends to further reduce the residual monomer contained in the adhesive sheet 1.

[0063] The conditions for the heating step are not particularly limited and can be appropriately adjusted. For example, the temperature for the heating step is preferably 40 to 200° C., more preferably 50 to 180° C., and further preferably 70 to 170° C. The time for the heating step is, for example, 5 seconds to 20 minutes, preferably 5 seconds to 10 minutes, and more preferably 10 seconds to 5 minutes.

[0064] (Photocurable composition) In this embodiment, the photocurable composition is a pressure-sensitive adhesive composition that forms the pressure-sensitive adhesive sheet 1 from the coating layer 12 by irradiation with light A or the like. The photocurable composition contains, for example, a monomer group containing a (meth)acrylic monomer and / or a partial polymer of the monomer group. The content of the (meth)acrylic component in the photocurable composition, i.e., the (meth)acrylic monomer and its partial polymer, may be 50% by weight or more, 60% by weight or more, 70% by weight or more, or even 80% by weight or more. In this case, an acrylic pressure-sensitive adhesive sheet 1 containing a (meth)acrylic polymer and its crosslinked product as the main components can be formed. However, the photocurable composition is not limited to the above examples. In this specification, (meth)acrylic means acrylic and methacrylic. (Meth)acrylate means acrylate and methacrylate.

[0065] An example of the (meth)acrylic monomer is a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms on the side chain. The number of carbon atoms in the alkyl group may be 7 or less, 6 or less, 5 or less, or even 4 or less. The alkyl group may be linear or branched. Examples of the (meth)acrylic acid alkyl ester are methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, n-pentyl (meth)acrylate, isopentyl (meth)acrylate, n-hexyl (meth)acrylate, isohexyl (meth)acrylate, isoheptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and the like. acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, n-dodecyl (meth)acrylate (lauryl (meth)acrylate), n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate and octadecyl (meth)acrylate. The (meth)acrylic acid alkyl ester may be n-butyl (meth)acrylate.

[0066] The content of the (meth)acrylic acid alkyl ester in the monomer group is, for example, 40% by weight or more, and may be 50% by weight or more, 60% by weight or more, 70% by weight or more, 80% by weight or more, 85% by weight or more, 90% by weight or more, or even 95% by weight or more. In calculating the content, the weight of the partially polymerized product is converted into the weight of each monomer before polymerization.

[0067] The monomer group may contain a carboxyl group-containing monomer. The carboxyl group-containing monomer may be a (meth)acrylic monomer, in other words, the (meth)acrylic monomer may contain a carboxyl group-containing monomer. Examples of the carboxyl group-containing monomer are (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. The content of the carboxyl group-containing monomer in the monomer group may be, for example, 10% by weight or less, 9% by weight or less, 8% by weight or less, 7% by weight or less, 6% by weight or less, 5.5% by weight or less, or even 5% by weight or less. The lower limit of the content may be, for example, 0.1% by weight or more, 0.5% by weight or more, or even 1% by weight or more. The monomer group may not contain a carboxyl group-containing monomer.

[0068] The monomer group may contain a hydroxyl group-containing monomer. The hydroxyl group-containing monomer may be a (meth)acrylic monomer, in other words, the (meth)acrylic monomer may contain a hydroxyl group-containing monomer. The hydroxyl group-containing monomer may contribute to improving the cohesive strength of the adhesive sheet. Examples of the hydroxyl group-containing monomer are 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)-methyl acrylate. The hydroxyl group-containing monomer is preferably 2-hydroxyethyl (meth)acrylate or 4-hydroxybutyl (meth)acrylate. The content of the hydroxyl group-containing monomer in the monomer group is, for example, 10% by weight or less, and may be 5% by weight or less, 4% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, 0.8% by weight or less, 0.5% by weight or less, 0.3% by weight or less, 0.2% by weight or less, or even 0.1% by weight or less. The lower limit of the content may be, for example, 0.01% by weight or more, 0.03% by weight or more, or even 0.05% by weight or more. The monomer group may not contain a hydroxyl group-containing monomer.

[0069] The monomer group may include a nitrogen atom-containing monomer. The nitrogen atom-containing monomer means a monomer having at least one nitrogen atom in the molecule (per molecule).

[0070] As the nitrogen atom-containing monomer, from the viewpoint of improving foaming and peeling resistance, N-vinyl cyclic amide, (meth)acrylamide, etc. are preferable. The nitrogen atom-containing monomer may be used alone or in combination of two or more kinds.

[0071] The N-vinyl cyclic amide is preferably represented by the following formula (1). [ka]

[0072] In formula (1), R 1 is a divalent organic group, preferably a divalent saturated or unsaturated hydrocarbon group, and more preferably a divalent saturated hydrocarbon group (e.g., an alkylene group having 3 to 5 carbon atoms). 1 are directly bonded via a single bond to form a ring structure.

[0073] As the N-vinyl cyclic amide represented by formula (1), from the viewpoint of improving foaming and peeling resistance, N-vinyl-2-pyrrolidone (NVP), N-vinyl-2-piperidone, N-vinyl-2-caprolactam, N-vinyl-3-morpholinone, N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholinedione, etc. are preferred, more preferably N-vinyl-2-pyrrolidone, N-vinyl-2-caprolactam, and even more preferably N-vinyl-2-pyrrolidone.

[0074] Examples of (meth)acrylamides include (meth)acrylamide, N-alkyl(meth)acrylamide, N,N-dialkyl(meth)acrylamide, etc. Examples of N-alkyl(meth)acrylamide include N-ethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, Nn-butyl(meth)acrylamide, N-octylacrylamide, etc. Examples of N-alkyl(meth)acrylamides include (meth)acrylamides having an amino group, such as dimethylaminoethyl(meth)acrylamide, diethylaminoethyl(meth)acrylamide, and dimethylaminopropyl(meth)acrylamide.

[0075] Examples of N,N-dialkyl(meth)acrylamides include N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide, N,N-di(n-butyl)(meth)acrylamide, and N,N-di(t-butyl)(meth)acrylamide.

[0076] (Meth)acrylamides also include, for example, various N-hydroxyalkyl (meth)acrylamides. Examples of N-hydroxyalkyl (meth)acrylamides include N-methylol (meth)acrylamide, N-(2-hydroxyethyl) (meth)acrylamide, N-(2-hydroxypropyl) (meth)acrylamide, N-(1-hydroxypropyl) (meth)acrylamide, N-(3-hydroxypropyl) (meth)acrylamide, N-(2-hydroxybutyl) (meth)acrylamide, N-(3-hydroxybutyl) (meth)acrylamide, N-(4-hydroxybutyl) (meth)acrylamide, and N-methyl-N-2-hydroxyethyl (meth)acrylamide.

[0077] (Meth)acrylamides also include, for example, various N-alkoxyalkyl(meth)acrylamides, such as N-methoxymethyl(meth)acrylamide and N-butoxymethyl(meth)acrylamide.

[0078] Examples of nitrogen atom-containing monomers other than N-vinyl cyclic amides and (meth)acrylamides include amino group-containing monomers such as aminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, and t-butylaminoethyl (meth)acrylate; cyano group-containing monomers such as acrylonitrile and methacrylonitrile; (meth)acryloylmorpholine, N-vinylpiperazine, N-vinylpyrrole, N-vinylimidazole, N-vinylpyrazine, N-vinylmorpholine, N-vinylpyrazole, vinylpyridine, vinylpyrimidine, vinyloxazole, vinylisoxazole, vinylthiazole, vinylisothiazole, vinylpyridazine, (meth)acryloylpyrrolidone, (meth)acryloylpyrrolidine, (meth)acryloylpiperidine, N-methyl Examples of the monomer include heterocyclic ring-containing monomers such as vinylpyrrolidone; maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, and N-phenylmaleimide; itaconimide monomers such as N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-laurylitaconimide, and N-cyclohexylitaconimide; and succinimide monomers such as N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, and N-(meth)acryloyl-8-oxyoctamethylenesuccinimide; and other imide group-containing monomers; and isocyanate group-containing monomers such as 2-(meth)acryloyloxyethylisocyanate.

[0079] The content of the nitrogen atom-containing monomer in the monomer group may be, for example, 40% by weight or less, 35% by weight or less, or even 30% by weight or less. The lower limit of the content may be, for example, 5% by weight or more, 7% by weight or more, or even 10% by weight or more. The monomer group may not contain a nitrogen atom-containing monomer.

[0080] In the photocurable composition, each of the above-mentioned monomers may be contained as a partial polymer. The partial polymer may be either a homopolymer or a copolymer. The partial polymer can contribute to the stable formation of the coating layer 12 by appropriately increasing the viscosity of the photocurable composition.

[0081] The photocurable composition usually contains a photopolymerization initiator. An example of the photopolymerization initiator is a photoradical generator that generates radicals by the above-mentioned light A. The photopolymerization initiator has an absorption coefficient for light of 340 nm, for example, of 0.1 L / (g·cm) or more, and may be 0.5 L / (g·cm) or more, 1.0 L / (g·cm) or more, 3.0 L / (g·cm) or more, or even 5.0 L / (g·cm) or more. The upper limit of this absorption coefficient is not particularly limited, and is, for example, 50 L / (g·cm) or less. The absorption coefficient of the photopolymerization initiator is a calculated value from the absorbance of a 0.01 mg / mL methanol solution measured by a visible-ultraviolet spectrophotometer using a quartz cell with a path length of 1 cm.

[0082] Examples of photopolymerization initiators include benzoin ethers such as benzoin methyl ether, benzoin isopropyl ether, and benzil dimethyl ketal; substituted benzoin ethers such as anisole methyl ether; substituted acetophenones such as 2,2-diethoxyacetophenone and 2,2-dimethoxy-2-phenylacetophenone; α-hydroxyalkylphenones such as 1-hydroxycyclohexyl-phenyl ketone, 2-hydroxy-2-methylpropiophenone, 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, and 2,2'-dihydroxy-2,2'-dimethyl-1,1'-[methylenebis(4,1-phenylene)]bis(propan-1-one); and substituted alpha alkyl phenones such as 2-methyl-2-hydroxypropiophenone. -ketols; aromatic sulfonyl chlorides such as 2-naphthalenesulfonyl chloride; photoactive oximes such as 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime; benzophenone compounds such as benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, and 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone; thioxanthone compounds such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, and 2,4-diethylthioxanthone;2,4,6-trichloro-s-triazine, 2-phenyl-4,6-bis(trichloromethyl)-s-triazine, 2-(p-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(p-tolyl)-4,6-bis(trichloromethyl)-s-triazine, 2-piperonyl-4,6-bis(trichloromethyl)-s-triazine, 2,4-bis(trichloromethyl)-6-styryl-s-triazine, 2-(naphth-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methoxy-naphth-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2,4-trichloromethyl-(piperonyl)-6-triazine, 2,4-trichloromethyl- triazine compounds such as (4'-methoxystyryl)-6-triazine; oxime ester compounds such as 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)], O-(acetyl)-N-(1-phenyl-2-oxo-2-(4'-methoxy-naphthyl)ethylidene)hydroxylamine; phosphine compounds such as bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; quinone compounds such as 9,10-phenanthrenequinone, camphorquinone, and ethylanthraquinone; borate compounds; carbazole compounds; imidazole compounds; and titanocene compounds. The photocurable composition may contain one or more photopolymerization initiators. In particular, α-hydroxyalkylphenone tends to have high absorption of light with wavelengths of 325 nm to 350 nm, and is therefore suitable for the production method of this embodiment.

[0083] The amount of the photopolymerization initiator in the photocurable composition is, for example, 20 parts by weight or less, and may be 10 parts by weight or less, 5.0 parts by weight or less, 3.0 parts by weight or less, 1.0 parts by weight or less, 0.5 parts by weight or less, or even 0.3 parts by weight or less, relative to 100 parts by weight of the total of the monomer group and its partial polymer. When the amount of the photopolymerization initiator is 1.0 part by weight or less, the weight average molecular weight of the polymer contained in the pressure-sensitive adhesive sheet 1 tends to be sufficiently large. The lower limit of the amount of the photopolymerization initiator is, for example, 0.02 parts by weight or more, and may be 0.05 parts by weight or more, relative to 100 parts by weight of the total of the monomer group and its partial polymer.

[0084] The photocurable composition may contain a crosslinking agent. An example of the crosslinking agent is a polyfunctional monomer having two or more polymerizable functional groups in one molecule. The polyfunctional monomer may be a (meth)acrylic monomer. An example of the polyfunctional monomer is a monomer having two or more C=C bonds in one molecule, and a monomer having one or more C=C bonds and one or more polymerizable functional groups such as epoxy groups, aziridine groups, oxazoline groups, hydrazine groups, methylol groups, etc. in one molecule. The polyfunctional monomer is preferably a monomer having two or more C=C bonds in one molecule.

[0085] Examples of the polyfunctional monomer include (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,2-ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol diacrylate (N DDA), 1,12-dodecanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, and other polyfunctional acrylates (such as ester compounds of polyhydric alcohols and (meth)acrylic acid); allyl (meth)acrylate, vinyl (meth)acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyl di(meth)acrylate, and hexyl di(meth)acrylate. The polyfunctional monomer is preferably a polyfunctional acrylate, and more preferably 1,9-nonanediol diacrylate, trimethylolpropane tri(meth)acrylate, hexanediol di(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0086] The amount of the crosslinking agent to be added varies depending on the molecular weight, the number of functional groups, etc., but may be, for example, 5 parts by weight or less, 3 parts by weight or less, 2 parts by weight or less, 1 part by weight or less, 0.5 parts by weight or less, or even 0.3 parts by weight or less, relative to 100 parts by weight in total of the monomer group and its partial polymer. The lower limit of the amount to be added is, for example, 0.01 parts by weight or more, or may be 0.05 parts by weight or more.

[0087] The photocurable composition may contain additives other than those described above. Examples of the additives include a chain transfer agent, a silane coupling agent, a viscosity modifier, a tackifier, a plasticizer, a softener, an antiaging agent, a filler, a colorant, an antioxidant, a surfactant, an antistatic agent, and an ultraviolet absorbing agent.

[0088] The content of the solvent in the photocurable composition is, for example, 5% by weight or less, and may be 4% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, or even 0.5% by weight or less. The photocurable composition may be substantially free of a solvent. The phrase "substantially free of a solvent" means that the solvent derived from additives or the like is allowed to be present at a content of, for example, 0.1% by weight or less, preferably 0.05% by weight or less, and more preferably 0.01% by weight or less.

[0089] The viscosity of the photocurable composition is preferably 1 to 100 poise. A photocurable composition having a viscosity in the above range is particularly suitable for forming the coating layer 12.

[0090] (Release liner) An example of the substrate of the release liner 13 (hereinafter, "liner substrate") is a resin film. Examples of resins that can be contained in the liner substrate are polyesters such as polyethylene terephthalate and polyethylene naphthalate, acetate resins, polyethersulfone, polycarbonate, polyamide, polyimide, polyolefin, (meth)acrylic resins, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl alcohol, polyarylate, and polyphenylene sulfide. The resin is preferably a polyester such as polyethylene terephthalate.

[0091] The release liner 13 may be transparent to light A. As an example, the spectral transmittance of the release liner 13 for light with a wavelength of 340 nm may be, for example, 60% or more, 70% or more, or even 80% or more. The upper limit of the spectral transmittance is not particularly limited, and may be, for example, 95% or less, or may be 90% or less. The spectral transmittance for light with a wavelength of 340 nm can be determined, for example, by measuring the total light transmittance spectrum in the wavelength range of 300 to 2000 nm for the release liner 13 using a commercially available spectrophotometer, and then determining the spectral transmittance from the spectrum obtained.

[0092] The thickness of the release liner 13 is, for example, 10 to 200 μm, and may be 25 to 150 μm.

[0093] The release liner 13 may include a layer other than the liner substrate. The release liner 13 may include a release layer. The release liner 13 includes, for example, a liner substrate and a release layer formed on one surface of the liner substrate. This release liner 13 can be used such that the release layer is on the coating layer 12 side.

[0094] The release layer is typically a cured layer of a release agent composition containing a release agent. As the release agent, various types of release agents can be used, such as silicone-based release agents, fluorine-based release agents, long-chain alkyl-based release agents, fatty acid amide-based release agents, and silica powder. The release liner 13 may be provided with a cured layer of a release agent composition containing a silicone-based release agent as a main component (hereinafter, "silicone release layer"). The silicone release layer is particularly suitable for achieving both adhesion to the pressure-sensitive adhesive sheet 1 and releasability. In this specification, the main component means the component with the largest content.

[0095] The silicone-based release agent is, for example, various curable silicone materials such as addition reaction type, condensation reaction type, ultraviolet curable type, electron beam curable type, and solventless type, and an addition reaction curable silicone material is preferred. An addition reaction curable silicone material is particularly suitable for forming a release layer that has both adhesion and releasability to the pressure-sensitive adhesive sheet 1. The curable silicone material may be a silicone-modified resin in which reactive silicone is introduced into an organic resin such as urethane, epoxy, or alkyd resin by graft polymerization or the like.

[0096] An example of the addition reaction curing silicone material is a polyorganosiloxane having a vinyl group or an alkenyl group in the molecule. The addition reaction curing silicone material may not have a hydrosilyl group. Examples of the alkenyl group are 3-butenyl, 4-pentenyl, 5-hexenyl, 6-heptenyl, 7-octenyl, 8-nonenyl, 9-decenyl, 10-undecenyl, and 11-dodecenyl. Examples of the polyorganosiloxane are polyalkylalkylsiloxanes such as polydimethylsiloxane, polydiethylsiloxane, and polymethylethylsiloxane, polyalkylarylsiloxane, and copolymers of multiple types of Si atom-containing monomers such as poly(dimethylsiloxane-diethylsiloxane). The polyorganosiloxane is preferably polydimethylsiloxane.

[0097] A release agent composition containing a silicone-based release agent as a main component (hereinafter referred to as "silicone release agent composition") usually contains a crosslinking agent. An example of the crosslinking agent is polyorganosiloxane having a hydrosilyl group. The crosslinking agent may have two or more hydrosilyl groups in one molecule.

[0098] The silicone release agent composition may contain a curing catalyst. An example of the curing catalyst is a platinum catalyst. An example of the platinum catalyst is chloroplatinic acid, an olefin complex of platinum, or an olefin complex of chloroplatinic acid. The amount of the platinum catalyst used is, for example, 10 to 1000 ppm (weight basis, platinum equivalent) based on the total solid content of the composition.

[0099] The silicone release agent composition may contain additives. Examples of additives are release control agents and adhesion promoters. Examples of release control agents are unreactive silicone resins, and more specific examples are organosiloxanes such as octamethylcyclotetrasiloxane, and MQ resins. The amount of the release control agent and adhesion promoter used is, for example, 1 to 30% by weight in total based on the total solid content of the composition. Further examples of additives are fillers, antistatic agents, antioxidants, ultraviolet absorbers, plasticizers, and colorants. The amount of the further additives used is, for example, 10% by weight or less in total based on the total solid content of the composition.

[0100] The silicone release agent composition may contain an organic solvent. Examples of the organic solvent include hydrocarbon solvents such as cyclohexane, n-hexane, and n-heptane; aromatic solvents such as toluene and xylene; ester solvents such as ethyl acetate and methyl acetate; ketone solvents such as acetone and methyl ethyl ketone; and alcohol solvents such as methanol, ethanol, and butanol. Two or more organic solvents may be contained. The amount of the organic solvent used is preferably 80 to 99.9% by weight of the silicone release agent composition.

[0101] The release layer can be formed, for example, by heating and drying a coating film containing the release agent composition formed on a liner substrate. Various coating methods such as roll coating, kiss roll coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, lip coating, and die coating can be applied to apply the release agent composition. For example, hot air drying can be applied to apply the heating and drying. The heating temperature and time vary depending on the heat resistance of the liner substrate, but are usually about 80 to 150°C and 10 seconds to 10 minutes. If necessary, irradiation with active energy rays such as ultraviolet rays may be used in combination.

[0102] The thickness of the release layer is, for example, 10 to 300 nm. The upper limit of the thickness may be 200 nm or less, 150 nm or less, 120 nm or less, 110 nm or less, 100 nm or less, less than 100 nm, 90 nm or less, 80 nm or less, 70 nm or less, less than 70 nm, or even 65 nm or less. The lower limit of the thickness may be 15 nm or more, 20 nm or more, 25 nm or more, 30 nm or more, 35 nm or more, 40 nm or more, 45 nm or more, or even 50 nm or more.

[0103] The release liner 13 may be in the form of a sheet or a continuous piece.

[0104] (Base sheet) An example of the base sheet 11 is a resin film. Examples of the resin contained in the base sheet 11 are the same as the examples of the resin that can be contained in the liner base material.

[0105] The base sheet 11 preferably has excellent transmittance to light A. As an example, the spectral transmittance of the base sheet 11 for light having a wavelength of 340 nm is, for example, 60% or more, and may be 70% or more, or even 80% or more. The higher the spectral transmittance, the more efficiently the coating layer 12 can be cured by light A. Furthermore, the base sheet 11 can be prevented from absorbing light A and generating heat. The upper limit of the spectral transmittance is not particularly limited, and may be, for example, 95% or less, or may be 90% or less. The spectral transmittance for light having a wavelength of 340 nm can be determined by the method described above for the release liner 13.

[0106] The thickness of the base sheet 11 is, for example, 10 to 200 μm, and may be 25 to 150 μm.

[0107] The base sheet 11 may have a release layer on the surface on the side of the coating layer 12. Examples of the release layer that the base sheet 11 may have and the manufacturing method thereof are the same as the examples of the release layer that the release liner 13 may have and the manufacturing method thereof. Both the release liner 13 and the base sheet 11 may have a release layer. In this case, both release layers may be formed from a release agent composition containing the same release agent as a main component. In addition, the thicknesses of both release layers may be different, and for example, the release layer provided on the base sheet 11 may be thicker.

[0108] For the base sheet 11, a sheet having a greater peeling strength from the adhesive sheet 1 than the release liner 13 can usually be selected.

[0109] The base sheet 11 may be in the form of a sheet or a continuous length.

[0110] (First laminate and its formation) The first laminate 10 may include an additional layer other than the base sheet 11, the coating layer 12, and the release liner 13. The additional layer may be disposed on the side of the base sheet 11 and / or the release liner 13 opposite to the side of the coating layer 12. The coating layer 12 is preferably in contact with the base sheet 11 and the release liner 13.

[0111] The first laminate 10 can be formed, for example, by forming a coating layer 12 on a base sheet 11 (or a release liner 13) and then disposing a release liner 13 (or base sheet 11) on the formed coating layer 12. Alternatively, the first laminate 10 may be formed by applying a photocurable composition in a poured manner into the space between the base sheet 11 and the release liner 13 that are held at a predetermined distance such that their main surfaces face each other.

[0112] The coating layer 12 can be formed by various coating methods such as roll coating, kiss roll coating, gravure coating, reverse coating, roll brush, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, lip coating, and die coating.

[0113] The thickness of the coating layer 12 can be adjusted depending on the desired thickness of the adhesive sheet 1, and may be, for example, 2 mm or less, 1 mm or less, 2 to 300 μm, 2 to 200 μm, 2 to 150 μm, 2 to 100 μm, 2 to 70 μm, 2 to 50 μm, 5 to 40 μm, 10 to 30 μm, 10 to 25 μm, or even 10 to 20 μm.

[0114] The first laminate 10 may include a long base sheet 11, a long coating layer 12, and a long release liner 13, in other words, may be long. The long first laminate 10 can be obtained, for example, by forming the coating layer 12 between the base sheet 11 and the release liner 13 while conveying them, the base sheet 11 and the release liner 13 being unwound from a roll.

[0115] (Adhesive sheet) The adhesive sheet 1 produced by the manufacturing method of this embodiment tends to have a small amount of remaining photopolymerization initiator. The adhesive sheet 1 with a small amount of remaining photopolymerization initiator tends to be suppressed from yellowing or foaming in a high temperature environment. As an example, the content of the photopolymerization initiator in the adhesive sheet 1 is, for example, 500wtppm or less, and may be 300wtppm or less, 200wtppm or less, 150wtppm or less, 120wtppm or less, 100wtppm or less, 80wtppm or less, 50wtppm or less, or even 30wtppm or less. The adhesive sheet 1 may be substantially free of a photopolymerization initiator.

[0116] Furthermore, in the adhesive sheet 1 produced by the manufacturing method of this embodiment, the polymerization rate of the monomer group tends to be high and the amount of remaining monomer group tends to be small. An adhesive sheet 1 having a small amount of remaining monomer group not only contributes to improving productivity, but also tends to suppress odor. This adhesive sheet 1 has the advantage of being easy to handle and transport. The polymerization rate of the monomer group in the adhesive sheet 1 is preferably 80% or more, and may be 85% or more, 90% or more, 95% or more, 97% or more, 98% or more, or even 99% or more.

[0117] In this embodiment, the polymerization rate of the monomer group is preferably 50% or more, and may be 60% or more, or even 70% or more, at the end of step A. The upper limit of this polymerization rate is not particularly limited, and may be, for example, 90% or less, or 80% or less.

[0118] According to the manufacturing method of this embodiment, the molecular weight of the polymer contained in the adhesive sheet 1 also tends to be large. As an example, when the manufacturing method of this embodiment is carried out using a sample having the same composition as the above-mentioned photocurable composition except that it does not contain a crosslinking agent, the weight average molecular weight (Mw) of the polymer obtained by polymerization of the monomer group contained in the sample may be, for example, 400,000 or more, 500,000 or more, 600,000 or more, 700,000 or more, 800,000 or more, 900,000 or more, or even 1 million or more. The larger this Mw is, the more likely peeling of the adhesive sheet 1 in a high temperature environment or the like is suppressed. The upper limit of Mw is not particularly limited, and is, for example, 3 million or less. The number average molecular weight (Mn) of the above-mentioned polymer may be, for example, 80,000 or more, 100,000 or more, 150,000 or more, 180,000 or more, 200,000 or more, or even 250,000 or more. The upper limit of Mn is not particularly limited, and is, for example, 600,000 or less. The weight average molecular weight (Mw) / number average molecular weight (Mn), which indicates the molecular weight distribution, is, for example, 1.8 to 10, and may be 1.8 to 7, or even 1.8 to 5. The weight average molecular weight and number average molecular weight are determined from values ​​measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene.

[0119] The gel fraction of the pressure-sensitive adhesive sheet 1 is, for example, 50% or more, and may be 75% or more, 80% or more, or even 85% or more.

[0120] The thickness of the pressure-sensitive adhesive sheet 1 is, for example, 2 mm or less, and may be 1 mm or less, 2 to 300 μm, 2 to 200 μm, 2 to 150 μm, 2 to 100 μm, 2 to 70 μm, 2 to 50 μm, 5 to 40 μm, 10 to 30 μm, 10 to 25 μm, or even 10 to 20 μm.

[0121] The pressure-sensitive adhesive sheet 1 produced by the manufacturing method of this embodiment is particularly suitable for applications requiring high light transmittance (for example, optical applications). However, the pressure-sensitive adhesive sheet 1 can also be used for various applications other than optical applications. The pressure-sensitive adhesive sheet 1 may be used as a double-sided tape.

[0122] Next, referring to FIG. 2, another example of a method for manufacturing a pressure-sensitive adhesive sheet will be described. In this example, a coating layer 12 of a photocurable composition is formed on one side of a long base sheet 11 unwound from a roll 31 by a coating device 32. Next, a long release liner 13 unwound from a roll 33 is placed on the coating layer 12 to form a long first laminate 10. Next, the first laminate 10 is subjected to a step A of irradiating light A from an LED 34 and a step B of irradiating light B from a light source 35a, and if necessary, a step C of irradiating light C from a light source 35b. This forms a long pressure-sensitive adhesive sheet 1. Next, the release liner 13 is peeled off from a second laminate 17 including the pressure-sensitive adhesive sheet 1 and wound up on a roll 36. The above steps are performed while the base sheet 11 and the release liner 13 are being transported. The method of FIG. 2 is particularly suitable for mass production of pressure-sensitive adhesive sheets.

[0123] Next, another example of a method for producing a pressure-sensitive adhesive sheet will be described with reference to Fig. 3. In this example, a photocurable composition is applied using an application device 32 between a long base sheet 11 unwound from a roll 31 and a long release liner 13 unwound from a roll 33. This forms a coating layer 12 containing the photocurable composition, and a long first laminate 10 is obtained.

[0124] Next, the first laminate 10 is conveyed so as to pass between the pair of light sources 38a and 38b. In detail, first, the first laminate 10 is conveyed through the first region 40A near the light source 38a. Next, the first reversing mechanism (first conveying roller 39a) is used to reverse the moving direction of the first laminate 10, and the first laminate 10 is conveyed in the opposite direction to the moving direction in the first region 40A. As a result, the first laminate 10 is conveyed through the second region 40B, which is closer to the light source 38b than the first region 40A. Next, the second reversing mechanism (second conveying roller 39b) is used to further reverse the moving direction of the first laminate 10, and the first laminate 10 is conveyed in the same direction as the moving direction in the first region 40A. As a result, the first laminate 10 is conveyed through the third region 40C near the light source 38b.

[0125] The light source 38a is typically an LED that emits light L1 with a peak wavelength of 325 nm to 350 nm. Similarly, the light source 38b is typically an LED that emits light L2 with a peak wavelength of 325 nm to 350 nm. The above-mentioned LED 34 can be used as the light sources 38a and 38b.

[0126] In the example of FIG. 3, the above-mentioned step A is performed in the first region 40A, the above-mentioned step B is performed in the second region 40B, and the above-mentioned step C is performed in the third region 40C. In detail, the total value (illuminance LB) of the illuminance of the light L1 from the base sheet 11 side and the illuminance of the light L2 from the release liner 13 side in the second region 40B is adjusted to be larger than the total value (illuminance LA) of the illuminance of the light L1 from the release liner 13 side and the illuminance of the light L2 from the base sheet 11 side in the first region 40A. Furthermore, the total value (illuminance LC) of the illuminance of the light L1 from the release liner 13 side and the illuminance of the light L2 from the base sheet 11 side in the third region 40C is adjusted to be larger than the above-mentioned illuminance LB. The positions and outputs of the light sources 38a and 38b are adjusted so that the illuminances LA to LC satisfy the above-mentioned relationship. As an example, the distance between the light source 38a and the first region 40A is adjusted to be greater than the distance between the light source 38b and the third region 40C.

[0127] By passing the sheet between a pair of light sources 38a and 38b, steps A to C are carried out to form a long adhesive sheet 1. Next, the release liner 13 is peeled off from the second laminate 17 containing the adhesive sheet 1, and the sheet is wound up into a roll 36. The method of Fig. 3 allows steps A to C to be carried out in a small space, and is particularly suitable for mass production of adhesive sheets.

[0128] 3, it is preferable that the polymerization rate of the monomer group is 50% or more at the end of the process A. In this case, when the moving direction of the first laminate 10 is reversed using the first reversing mechanism (first conveying roller 39a), the members constituting the first laminate 10 tend not to have poor appearance such as wrinkles, streaks, or lifting.

[0129] [Method of manufacturing optical film with adhesive sheet] An example of a method for producing an optical film with a pressure-sensitive adhesive sheet according to this embodiment will be described with reference to Fig. 4. In the example of Fig. 4, an optical film 2 is disposed on exposed surface 18 of a pressure-sensitive adhesive sheet 1 formed by peeling off release liner 13 from second laminate 17 produced by the above-mentioned method, to form optical film 21 with a pressure-sensitive adhesive sheet. Note that, before disposing optical film 2, exposed surface 18 of pressure-sensitive adhesive sheet 1 may be subjected to a surface modification treatment.

[0130] The optical film 21 with adhesive sheet includes a base sheet 11, an adhesive sheet 1, and an optical film 2 in this order. The optical film 21 with adhesive sheet can be used as it is or after peeling off the base sheet 11, for example, as an optical laminate including the adhesive sheet 1 and the optical film 2 in an image display device or the like. The optical laminate may be attached to an object (for example, an image forming panel) via the adhesive sheet 1. However, the use of the optical film 21 with adhesive sheet is not limited to the above example. An additional member such as an optical film may be disposed on the exposed surface 18 formed by peeling off the base sheet 11 from the optical film 21 with adhesive sheet. As an example, an optical film 22 with adhesive sheet including an optical film 2A, an adhesive sheet 1, and an optical film 2B in this order can be formed (see FIG. 5). The optical films 2A and 2B may be the same or different from each other.

[0131] The optical film 2 may be disposed directly or indirectly on the exposed surface 18. In other words, the optical film 2 may be disposed so as to be in contact with the exposed surface 18, or may be disposed with another layer sandwiched between the optical film 2 and the exposed surface 18.

[0132] With reference to Fig. 6, another example of the method for producing an optical film with a pressure-sensitive adhesive sheet of the present embodiment will be described. In this example, a long optical film 2 is arranged on the exposed surface 18 of the pressure-sensitive adhesive sheet 1 in the third laminate 15 formed by the method of Fig. 2 to form a long optical film with a pressure-sensitive adhesive sheet 21. The optical film 2 is unwound from a roll 37 and arranged on the exposed surface 18. As shown in Fig. 6, the formation of the pressure-sensitive adhesive sheet 1 and the formation of the optical film with a pressure-sensitive adhesive sheet 21 may be carried out continuously. The method of Fig. 6 is particularly suitable for mass production of the optical film with a pressure-sensitive adhesive sheet 21.

[0133] The optical film 2 is, for example, a film including at least one selected from the group consisting of a polarizing film and a retardation film. The optical film 2 may be a laminated film including a polarizing film and / or a retardation film. The optical film 2 may include a glass film. However, the optical film 2 is not limited to the above examples.

[0134] The polarizing film includes a polarizer. The polarizing film typically includes a polarizer and a protective film (transparent protective film). The protective film is disposed, for example, in contact with the main surface (surface having the widest area) of the polarizer. The polarizer may be disposed between two protective films. The protective film may be disposed on at least one surface of the polarizer.

[0135] The polarizer is not particularly limited, and examples thereof include hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and partially saponified ethylene-vinyl acetate copolymer films, which are uniaxially stretched after adsorbing dichroic substances such as iodine and dichroic dyes; polyene-based oriented films such as dehydrated polyvinyl alcohol and dehydrochlorinated polyvinyl chloride; etc. Polarizers are typically made of polyvinyl alcohol films (polyvinyl alcohol films include partially saponified ethylene-vinyl acetate copolymer films) and dichroic substances such as iodine.

[0136] The thickness of the polarizer is not particularly limited, and may be, for example, 80 μm or less, 50 μm or less, 30 μm or less, 25 μm or less, or even 20 μm or less. The lower limit of the thickness of the polarizer is not particularly limited, and may be, for example, 1 μm or more, 5 μm or more, 10 μm or more, or even 15 μm or more. A thin polarizer (for example, a thickness of 20 μm or less) is suppressed in dimensional change, and can contribute to improving the durability of the optical laminate, particularly the durability at high temperatures.

[0137] As the material of the protective film, for example, a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, moisture blocking property, isotropy, etc. is used. Specific examples of such thermoplastic resins include cellulose resins such as triacetyl cellulose, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, cyclic polyolefin resins (norbornene-based resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. The material of the protective film may be a thermosetting resin or an ultraviolet-curing resin such as a (meth)acrylic, urethane, acrylic urethane, epoxy, or silicone-based resin. When the polarizing film has two protective films, the materials of the two protective films may be the same or different from each other. For example, a protective film made of a thermoplastic resin may be bonded to one main surface of the polarizer via an adhesive, and a protective film made of a thermosetting resin or an ultraviolet-curing resin may be bonded to the other main surface of the polarizer. The protective film may contain one or more types of optional additives, such as ultraviolet absorbers, antioxidants, lubricants, plasticizers, release agents, color inhibitors, flame retardants, nucleating agents, antistatic agents, pigments, and colorants.

[0138] The thickness of the protective film can be appropriately determined, but is generally about 10 to 200 μm in terms of strength, workability such as handleability, thinness, and the like.

[0139] The polarizer and the protective film are usually adhered to each other via a water-based adhesive or the like. Examples of the water-based adhesive include an isocyanate-based adhesive, a polyvinyl alcohol-based adhesive, a gelatin-based adhesive, a vinyl-based latex, a water-based polyurethane, and a water-based polyester. Examples of adhesives other than the above-mentioned adhesives include an ultraviolet-curable adhesive and an electron beam-curable adhesive. The electron beam-curable polarizing plate adhesive exhibits suitable adhesion to various protective films. The adhesive may contain a metal compound filler.

[0140] In the polarizing film, a retardation film or the like can be formed on the polarizer instead of the protective film. Another protective film or a retardation film or the like can be further provided on the protective film.

[0141] The protective film may have a hard coat layer on the surface opposite to the surface bonded to the polarizer, and may also be subjected to treatments for the purposes of anti-reflection, anti-sticking, diffusion, anti-glare, etc.

[0142] The polarizing film may be a circular polarizing film.

[0143] The retardation film may be one obtained by stretching a polymer film or one obtained by aligning and fixing a liquid crystal material. The retardation film has birefringence, for example, in the in-plane and / or thickness direction.

[0144] Retardation films include anti-reflection retardation films (see JP 2012-133303 A,

[0221] ,

[0222] ,

[0228] ), viewing angle compensation retardation films (see JP 2012-133303 A,

[0225] ,

[0226] ), and tilted orientation retardation films for viewing angle compensation (see JP 2012-133303 A,

[0227] ).

[0145] The specific configuration of the retardation film, for example, the retardation value, arrangement angle, three-dimensional birefringence, whether it is a single layer or a multilayer, and the like, are not particularly limited, and any known retardation film can be used.

[0146] The thickness of the retardation film is preferably 20 μm or less, more preferably 10 μm or less, further preferably 1 to 9 μm, and particularly preferably 3 to 8 μm.

[0147] The retardation film may include, for example, a quarter wave plate and / or a half wave plate in which a liquid crystal material is oriented and fixed.

[0148] [Manufacturing method of image display device] An image display device may be formed using the optical film with adhesive sheet formed by the above-mentioned manufacturing method. The image display device may be formed, for example, by bonding the optical film 21, 22 with adhesive sheet to an image display panel. The bonding may be performed by using an adhesive sheet 1. The image display device may be an organic EL display or a liquid crystal display. However, the image display device is not limited to the above examples. The image display device may be an electroluminescence (EL) display, a plasma display (PD), a field emission display (FED: Field Emission Display), or the like. The image display device may be used for home appliances, in-vehicle applications, public information displays (PID), and the like. EXAMPLES

[0149] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the examples shown below.

[0150] [Monomer Syrup A1] 99 parts by weight of n-butyl acrylate (BA), 1 part by weight of 4-hydroxybutyl acrylate (HBA), 0.05 parts by weight of 1-hydroxycyclohexyl-phenyl ketone (Omnirad184, manufactured by IGM Resins BV) as a photopolymerization initiator, and 0.05 parts by weight of 2,2-dimethoxy-1,2-diphenylethan-1-one (Omnirad651, manufactured by IGM Resins BV) were placed in a four-bottom flask and irradiated with ultraviolet light under a nitrogen atmosphere to obtain a partially photopolymerized monomer syrup A1. The ultraviolet light irradiation was continued until the viscosity of the liquid in the flask (measurement conditions: BH viscometer No. 5 rotor, 10 rpm, measurement temperature 30°C) reached approximately 20 Pa·s.

[0151] [Monomer syrup A2~A6] Monomer syrups A2 to A6 were prepared in the same manner as for the monomer syrup A1, except that the monomers used were changed as shown in Table 1.

[0152] [Table 1]

[0153] The abbreviations in Table 1 are as follows. BA: n-butyl acrylate AA: Acrylic acid HBA: 4-hydroxybutyl acrylate Omnirad184: 1-Hydroxycyclohexyl-phenyl ketone (Omnirad184, IGM Resins BV) Omnirad651: 2,2-dimethoxy-1,2-diphenylethan-1-one (Omnirad651, IGM Resins BV) Omnirad819: Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Omnirad819, IGM Resins BV) Omnirad127: 2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl)2-methylpropan-1-one (Omnirad127, IGM Resins BV) Omnirad2959: 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone (Omnirad2959, IGM Resins BV)

[0154] [Photocurable composition C1~C10] Next, the monomer syrup, the monomer, and the crosslinking agent were mixed so as to have the composition shown in Table 2 below, thereby obtaining photocurable compositions C1 to C10.

[0155] [Table 2]

[0156] The abbreviations in Table 2 are as follows. AA: Acrylic acid NVP: N-vinyl-2-pyrrolidone NDDA: 1,9-nonanediol diacrylate

[0157] The final compositions of the monomers contained in the photocurable compositions C6 and C7 are shown in Table 3 below.

[0158] [Table 3]

[0159] The abbreviations in Table 3 are as follows. BA: n-butyl acrylate AA: Acrylic acid HBA: 4-hydroxybutyl acrylate NVP: N-vinyl-2-pyrrolidone

[0160] Example 1 [Preparation of release liner] Addition reaction curing type silicone (LTC761 containing hexenyl group-containing polyorganosiloxane, 30 wt% toluene solution, manufactured by Dow Corning Toray) 30 parts by weight, release control agent (BY24-850 containing unreactive silicone resin, manufactured by Dow Corning Toray) 0.9 parts by weight, curing catalyst (SRX212 containing platinum catalyst, manufactured by Dow Corning Toray) 2 parts by weight, and toluene / hexane mixed solvent (volume ratio 1: 1) as a dilution solvent were mixed to obtain a silicone-based release agent composition. The concentration of silicone solids in the release agent composition was 1.0 wt%. Next, the release agent composition was applied to one side of a liner substrate (Lumirror XD500P, a polyester film, thickness 75 μm) with a wire bar and heated at 130 ° C for 1 minute to prepare a release liner having a release layer (thickness 60 nm) on one side.

[0161] [Preparation of adhesive sheet] The photocurable composition C1 was applied to one side of a substrate sheet (Lumirror XD500P, a polyester film without a release layer, thickness 75 μm) using an applicator to form a coating layer (thickness 20 μm). Next, a release liner was placed on the formed coating layer to obtain a first laminate. The release liner was placed so that the release layer was in contact with the coating layer. Next, a light with an illuminance of 9 mW / cm was applied from the substrate sheet side of the first laminate. 2 The first laminate was irradiated with light A from an LED under the conditions of 100 s, 160 s irradiation time (step A). ​​The peak wavelength of light A was 340 nm. Next, the first laminate was irradiated with light A from the base sheet side at an illuminance of 22 mW / cm 2 The coating layer was then photocured, and the adhesive sheet of Example 1 (thickness: 20 μm) was obtained by sandwiching the coating layer between the base sheet and the release liner. The illuminance of the light was measured using an illuminance meter (UD-T3040T2, manufactured by Topcon Technohouse).

[0162] (Example 2 and Comparative Examples 1 to 3) Pressure-sensitive adhesive sheets of Example 2 and Comparative Examples 1 to 3 sandwiched between a base sheet and a release liner were obtained in the same manner as in Example 1, except that the photocurable composition, light source, and light irradiation conditions used were changed as shown in Table 4. In Table 4, "B / L" means a black light source.

[0163] [Polymerization rate of monomer group] For the pressure-sensitive adhesive sheets produced in Examples 1-2 and Comparative Examples 1-3, the polymerization rate of the monomer group was determined by the following method. First, the base sheet and release liner were peeled off from the pressure-sensitive adhesive sheet, and the weight W0 (weight before drying) of the pressure-sensitive adhesive sheet was measured. Next, the pressure-sensitive adhesive sheet was dried by heating at 130°C for 2 hours, and then cooled at room temperature (23°C) for about 20 minutes, and the weight W1 (weight after drying) of the pressure-sensitive adhesive sheet was measured. Based on the weight W0 (g) and weight W1 (g), the polymerization rate of the monomer group was calculated by the following formula. Polymerization rate (%)=W1 / W0×100

[0164] [Number average molecular weight (Mn) and weight average molecular weight (Mw) of the polymer] First, samples were prepared that had the same composition as the photocurable compositions used in Examples 1-2 and Comparative Examples 1-3, except that they did not contain a crosslinking agent. The samples were irradiated with light under the conditions of the corresponding Examples and Comparative Examples. As a result, the monomer groups contained in the samples were polymerized to form a polymer. The number average molecular weight (Mn) and weight average molecular weight (Mw) of the polymer were measured.

[0165] The above Mn and Mw were measured by GPC (gel permeation chromatography). The measurement device and conditions were as follows. The measurement device and conditions were different for the NVP-containing composition and the NVP-free composition.

[0166] (NVP-free composition) Analytical equipment: Tosoh HLC-8120GPC Column: Tosoh G7000H XL +GMH XL +GMH XL Column size: 7.8mmφ×30cm each, total 90cm Column temperature: 40℃ ·Flow rate: 0.8mL / min ·Injection volume: 100μL Eluent: Tetrahydrofuran Detector: Differential refractometer (RI) Standard sample: polystyrene

[0167] (NVP-containing composition) Analytical equipment: Agilent Technologies, Agilent 1200 Column: Tosoh Corporation, TSKgel SuperAWM-H+superAW4000+superAW2500 Column size: 6.0mmφ×15cm each, total 45cm Column temperature: 40℃ ·Flow rate: 0.4mL / min ·Injection volume: 40μL Eluent: N,N-dimethylformamide (DMF) Detector: Differential refractometer (RI) Standard sample: polystyrene

[0168] [Table 4]

[0169] (Examples 3 to 13 and Comparative Example 4) Pressure-sensitive adhesive sheets of Examples 3 to 13 and Comparative Example 4 sandwiched between a base sheet and a release liner were obtained in the same manner as in Example 1, except that the photocurable composition, light source, and light irradiation conditions used were changed as shown in Table 5. Note that in Examples 4 to 10, step C of irradiating light C from the side of the base sheet in the first laminate was further carried out after step B. In Table 5, "B / L" means a black light source, and "MH / L" means a metal halide lamp.

[0170] [Polymerization rate of monomer group] For the pressure-sensitive adhesive sheets produced in Examples 3 to 13 and Comparative Example 4, the polymerization ratios of the monomer groups were calculated by the method described above.

[0171] [Number average molecular weight (Mn) and weight average molecular weight (Mw) of the polymer] Samples having the same composition as the photocurable compositions used in Examples 3 to 13 and Comparative Example 4 were prepared, except that they did not contain a crosslinking agent, and the number average molecular weight (Mn) and weight average molecular weight (Mw) of the polymer were measured by the above-mentioned method.

[0172] [Table 5]

[0173] As can be seen from Tables 4 and 5, the pressure-sensitive adhesive sheets of the examples produced by irradiating light A with a peak wavelength of 325 nm to 350 nm using an LED in step A, and then irradiating light B with an illuminance higher than that of light A in step B, had higher polymerization rates of the monomer groups than the comparative examples. From this, it can be said that the production method of this embodiment is suitable for efficiently producing pressure-sensitive adhesive sheets. [Industrial Applicability]

[0174] The pressure-sensitive adhesive sheet produced by the production method of the present invention can be used, for example, in optical laminates and image display devices. [Explanation of symbols]

[0175] 1 Adhesive sheet 2. Optical Film 10 First laminate 11 Base sheet 12 Coating layer 13 Release Liner 18 Exposed surface 21,22 Optical film with adhesive sheet 34 Light Emitting Diode 35a,35b light source

Claims

1. A step A of irradiating a coating layer containing a photocurable composition with light A from a light emitting diode; a step B of irradiating the coating layer with light B after the step A; a step C of irradiating the coating layer with light C after the step B; Including, The light A has a peak wavelength of 325 nm to 350 nm, an illuminance LB of the light B irradiated to the coating layer is greater than an illuminance LA of the light A irradiated to the coating layer; The method for manufacturing a pressure-sensitive adhesive sheet, wherein an illuminance LC of the light C irradiated to the coating layer is greater than an illuminance LB.

2. The method of claim 1 , wherein the peak wavelength is 340±10 nm.

3. The method according to claim 1 , wherein in the step A, the light A is irradiated onto a laminate including a base sheet, the coating layer, and a release liner in this order.

4. The illuminance LA is 2.0 to 30 mW / cm 2 The method according to claim 1,

5. The method according to claim 1, wherein a ratio of the illuminance LB to the illuminance LA is 1.2 to 10.

6. 2. The method according to claim 1, wherein the light source of the light B is at least one selected from the group consisting of a light emitting diode, a metal halide lamp, and a black light source.

7. The method according to claim 1 , wherein the photocurable composition comprises a monomer group including a (meth)acrylic monomer and / or a partial polymer of the monomer group.

8. The method according to claim 7 , wherein the polymerization rate of the monomer group at the time when the step A is completed is 50% or more.

9. The method according to claim 7 , wherein the polymerization rate of the monomer group in the pressure-sensitive adhesive sheet is 95% or more.

10. The photocurable composition includes a photopolymerization initiator, The method according to claim 7 , wherein the amount of the photopolymerization initiator is 1.0 part by weight or less per 100 parts by weight of the total of the monomer group and the partially polymerized product.

11. The method according to claim 1 , wherein the photocurable composition has a solvent content of 5% by weight or less.

12. A method for producing an optical film with a pressure-sensitive adhesive sheet, comprising: arranging an optical film on an exposed surface of the pressure-sensitive adhesive sheet formed by the manufacturing method according to any one of claims 1 to 11 to form an optical film with a pressure-sensitive adhesive sheet.

13. The method according to claim 12 , wherein the optical film comprises at least one film selected from the group consisting of a polarizing film and a retardation film.

14. A method for producing an image display device, comprising bonding an optical film with a pressure-sensitive adhesive sheet formed by the method according to claim 12 to an image display panel to form an image display device.

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