Method for manufacturing adhesive sheet, method for manufacturing optical film with adhesive sheet, and method for manufacturing image display device

Abstract

Provided is a novel production method suitable for efficiently producing an adhesive sheet. This method for producing an adhesive sheet (1) comprises a step for forming an adhesive sheet (1) by irradiating a coating layer (12) containing a photocurable composition with light (14) from a light-emitting diode (34). The peak wavelength of the light (14) irradiated on the coating layer (12) is 325 nm to 350 nm. The method for manufacturing the optical film (21) with the adhesive sheet comprises the step of arranging the optical film (2) on the exposed surface (18) of the adhesive sheet (1) formed by the manufacturing method to form the optical film (21) with the adhesive sheet.

Description

Technical Field

[0001] This invention relates to a method for manufacturing an adhesive sheet, a method for manufacturing an optical film with an adhesive sheet, and a method for manufacturing an image display device. Background Technology

[0002] Various image display devices, such as liquid crystal displays and electroluminescent (EL) displays, generally possess optical laminates comprising optical films such as polarizing films and adhesive sheets. Adhesive sheets are typically used for bonding the optical films within the optical laminate and for bonding the optical laminate to the image display panel. Typically, adhesive sheets are obtained by curing a monomer group containing acrylic monomers, silicone monomers, etc., through polymerization and cross-linking.

[0003] Patent Document 1 discloses an example of an adhesive sheet. In Patent Document 1, the adhesive sheet is manufactured by irradiating a coating layer of an adhesive composition disposed between two release liner with light.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent No. 6688054 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] Typical adhesive sheets can be manufactured using, for example, the following thermosetting method. First, an adhesive composition is prepared by combining a crosslinking agent with a polymer made by polymerizing monomers in an organic solvent. This adhesive composition is then applied to a substrate such as a release liner, and the organic solvent is removed by heating to form a sheet. Heating and curing are performed as needed to complete crosslinking, thereby manufacturing the adhesive sheet. In this manufacturing process, the heat required for solvent removal and curing necessitates the combustion of large quantities of fuels such as LNG. Furthermore, directly releasing the removed organic solvents into the atmosphere poses a serious risk of environmental damage. Therefore, in most cases, the organic solvents are burned in a deodorizing furnace before release. In this case, not only does the fuel used for combustion in the deodorizing furnace become more necessary, but the organic solvents themselves are also converted into CO2 and emitted into the atmosphere during combustion, making it a manufacturing process with very high CO2 emissions.

[0009] 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. The manufacturing of adhesive sheets also requires the selection of manufacturing processes that do not use organic solvents and have low CO2 emissions.

[0010] Compared to the aforementioned thermosetting method, the method of producing adhesive sheets using light (photocuring method) can reduce the energy required for adhesive sheet formation and CO2 emissions. In the photocuring method, for example, a black light source can be used (Patent Document 1). However, according to the research of the present inventors, in the photocuring method using a black light source, there is a tendency for a high residual amount of photopolymerization initiator in the produced adhesive sheet, and there is room for improvement from the viewpoint of efficiently producing adhesive sheets.

[0011] Therefore, the object of the present invention is to provide a new manufacturing method suitable for efficiently producing adhesive sheets.

[0012] Problem Solving Methods

[0013] This invention provides a method for manufacturing an adhesive sheet, comprising:

[0014] The process of forming an adhesive sheet by irradiating a coating layer containing a photocurable composition with light from a light-emitting diode.

[0015] The peak wavelength of the light irradiating the above-mentioned coating layer is 325nm~350nm.

[0016] Furthermore, the present invention provides a method for manufacturing an optical film with an adhesive sheet, comprising:

[0017] An optical film with an adhesive sheet is formed by placing an optical film on the exposed surface of the adhesive sheet formed by the above manufacturing method.

[0018] Furthermore, the present invention provides a method for manufacturing an image display device, comprising:

[0019] An image display device is formed by bonding an optical film with an adhesive sheet, which is manufactured by the above-described method, to an image display panel.

[0020] The effects of the invention

[0021] According to the present invention, a new manufacturing method suitable for efficiently producing adhesive sheets can be provided. Attached Figure Description

[0022] Figure 1 This is a schematic diagram illustrating an example of the method for manufacturing the adhesive sheet of the present invention.

[0023] Figure 2 This is a schematic diagram illustrating an example of the method for manufacturing the adhesive sheet of the present invention.

[0024] Figure 3 This is a schematic diagram illustrating an example of the method for manufacturing the adhesive sheet of the present invention.

[0025] Figure 4This is a schematic diagram illustrating an example of the method for manufacturing the optical film with adhesive sheet according to the present invention.

[0026] Figure 5 This is a schematic diagram illustrating an example of the method for manufacturing the optical film with adhesive sheet according to the present invention.

[0027] Figure 6 This is a schematic diagram illustrating an example of the method for manufacturing the optical film with adhesive sheet according to the present invention. Detailed Implementation

[0028] The method for manufacturing an adhesive sheet according to the first aspect of the present invention includes a step of forming an adhesive sheet by irradiating a coating layer containing a photocurable composition with light from a light-emitting diode, wherein the peak wavelength of the light irradiating the coating layer is 325 nm to 350 nm.

[0029] In the second aspect of the present invention, for example, in the manufacturing method of the first aspect, the peak wavelength is 340±10nm.

[0030] In a third aspect of the present invention, for example, in the manufacturing method of the first or second aspect, the illuminance of the light irradiating the coating layer is 2.0 to 30 mW / cm². 2 .

[0031] In the fourth aspect of the present invention, for example, in the manufacturing method of any of the first to third aspects, the above light is irradiated onto a laminate comprising a substrate sheet, the above-mentioned coating layer and a release liner in sequence.

[0032] In the fifth aspect of the present invention, for example, in the manufacturing method of any of the first to fourth aspects, the time for irradiating the coating layer with the light is 10 seconds to 1000 seconds.

[0033] In the sixth aspect of the present invention, for example, in the manufacturing method of any of the first to fifth aspects, the temperature of the coating layer is maintained at 10°C to 30°C during the period when the coating layer is irradiated with the light.

[0034] In the seventh aspect of the present invention, for example, in the manufacturing method of any of the first to sixth aspects, the coating layer is irradiated with the light in a gas atmosphere with an oxygen concentration of 500 volppm or less.

[0035] In the eighth aspect of the present invention, for example, in the manufacturing method of any of the first to seventh aspects, the photocurable composition comprises a monomer group and / or a portion of the polymer of the monomer group, wherein the monomer group comprises (meth)acrylic monomers.

[0036] In the ninth aspect of the present invention, for example, in the manufacturing method of the eighth aspect, the polymerization rate of the monomer group in the adhesive sheet is 80% or more.

[0037] In the tenth aspect of the present invention, for example, in the manufacturing method of the eighth or ninth aspect, the photocurable composition comprises a photopolymerization initiator, and the amount of the photopolymerization initiator is 1.0 part by weight or less relative to the total 100 parts by weight of the monomer group and the polymer.

[0038] In the eleventh aspect of the present invention, for example, in the manufacturing method of the tenth aspect, the content of the photopolymerization initiator in the adhesive sheet is 500 wtppm or less.

[0039] In the 12th aspect of the present invention, for example, in the manufacturing method of any of the 1st to 11th aspects, the solvent content in the above-mentioned photocurable composition is 5% by weight or less.

[0040] The method for manufacturing an optical film with an adhesive sheet according to the 13th aspect of the present invention includes: forming an optical film with an adhesive sheet by disposing an optical film on the exposed surface of an adhesive sheet formed by any of the manufacturing methods of the 1st to 12th aspects.

[0041] In the 14th aspect of the present invention, for example, in the manufacturing method of the 13th aspect, the optical film comprises at least one film selected from polarizing films and phase difference films.

[0042] The manufacturing method of the image display device according to the 15th aspect of the present invention includes: bonding an optical film with an adhesive sheet formed by the manufacturing method of the 13th or 14th aspect to an image display panel to form an image display device.

[0043] The present invention will now be described in detail, but the present invention is not limited to the following embodiments. Any modifications can be made to implement the invention without departing from the spirit of the invention.

[0044] [Implementation method of manufacturing adhesive sheet]

[0045] like Figure 1 As shown, the manufacturing method of the adhesive sheet 1 in this embodiment includes a step of forming the adhesive sheet 1 by irradiating a coating layer 12 containing a photocurable composition with light 14 from a light-emitting diode (LED) 34. In this step, the peak wavelength of the light 14 irradiating the coating layer 12 is 325 nm to 350 nm. The illuminance of this light 14 is preferably 2.0 to 30 mW / cm². 2 .

[0046] In the manufacturing method of this embodiment, by utilizing the light 14 described above, compared to the case of using a black light source, there is a tendency for a smaller residual amount of photopolymerization initiator in the formed adhesive sheet 1. Furthermore, according to the research of the present inventors, when utilizing the light 14 described above, compared to the case of using, for example, an LED emitting light with a peak wavelength of approximately 365 nm, there is a tendency for a higher polymerization rate of the monomer groups in the adhesive sheet 1. Thus, the manufacturing method of this embodiment is suitable for efficiently producing the adhesive sheet 1.

[0047] As described above, in the manufacturing method of this embodiment, light 14 from an LED is utilized. Compared to black light sources, LEDs not only allow for easier adjustment of illuminance but also tend to have a longer lifespan. From the viewpoint of reducing environmental impact, LEDs are superior to black light sources that utilize mercury. Furthermore, according to the inventors' research, LEDs emitting light 14 with a peak wavelength of 325nm to 350nm tend to generate less heat and have easier temperature control of the coating layer 12 compared to LEDs emitting light with a peak wavelength of around 365nm. Light 14 with a peak wavelength of 325nm to 350nm also tends to have higher suitability for the absorption wavelength of the photopolymerization initiator compared to light with a peak wavelength of around 365nm. It should be noted that, to the best of the inventors' knowledge, there have been no reported examples to date of using LEDs emitting light with a peak wavelength of 325nm to 350nm to manufacture adhesive sheets.

[0048] In detail, the manufacturing method of this embodiment can be carried out by the following method. First, a laminate (first laminate) 10 comprising a substrate sheet 11, a coating layer 12 comprising a photocurable composition, and a release liner 13 is formed. The first laminate 10 is irradiated with light 14. The irradiation of light 14 is typically performed from one side of the substrate sheet 11. At this time, the light 14 passes through the substrate sheet 11 and reaches the coating layer 12, causing the coating layer 12 to cure. However, the irradiation of light 14 can also be performed from one side of the release liner 13, or from both sides of the release liner 13 and the substrate sheet 11.

[0049] The resulting adhesive sheet 1 is held between the substrate sheet 11 and the release liner 13 until the release liner 13 is peeled off, thus forming part of the second laminate 17. By peeling the release liner 13 from the second laminate 17, a third laminate 15 comprising the substrate sheet 11 and the adhesive sheet 1 is obtained. In the third laminate 15, the surface of the adhesive sheet 1 is exposed to the outside.

[0050] As described above, the peak wavelength of the light 14 irradiating the first laminate 10 (specifically, the coating layer 12) is 325 nm to 350 nm. The peak wavelength of the light 14 is preferably 340 ± 10 nm (330 nm to 350 nm), but can be 340 ± 5 nm (335 nm to 345 nm), 340 ± 2 nm (338 nm to 342 nm), or 340 nm. The peak wavelength refers to the wavelength at which the intensity of the light 14 reaches its maximum value in a spectrum showing the relationship between the wavelength and intensity of the light 14. The light 14 may also have a peak wavelength in other wavelength ranges besides 325 nm to 350 nm, but it is preferable not to have one.

[0051] As described above, the illuminance of the light 14 irradiating the first laminate 10 (specifically, the coating layer 12) is preferably 2.0 to 30 mW / cm². 2 By setting the illuminance of light 14 to 2.0 mW / cm² 2 The above indicates a tendency to allow the coating layer 12 to cure uniformly. Furthermore, by setting the illuminance of light 14 to 30 mW / cm²... 2 The following suggests that the polymerization rate of the photoinitiator contained in the photocurable composition can be appropriately adjusted, and the polymerization rate of the monomer group tends to increase easily. Under an illuminance of 30 mW / cm² at light 14... 2 In the following situations, there is a tendency for the rapid heating of the coating layer 12 to be suppressed, making it difficult to produce an undesirable appearance of the adhesive sheet 1. It should be noted that when light 14 is irradiated from both the release liner 13 and the substrate sheet 11, the combined illuminance of the light 14 from the release liner 13 side and the illuminance of the light 14 from the substrate sheet 11 side is preferably adjusted to 2.0~30 mW / cm². 2 .

[0052] The preferred illuminance for light 14 is 2.5 mW / cm². 2 The above can be 3.0mW / cm 2 Above, 3.5mW / cm 2 Above, 4.0mW / cm 2 Above, 5.0mW / cm 2 Above, 6.0mW / cm 2 Above, 7.0mW / cm 2 Above, 8.0mW / cm 2 Above, 9.0mW / cm 2 The above, and thus can be 10mW / cm 2 That's all. The upper limit of illuminance for light 14 is, for example, 25 mW / cm². 2 The following can be 20mW / cm 2 Therefore, it can be further reduced to 15mW / cm 2It should be noted that the illuminance of light 14 can be adjusted not only by controlling LED 34 itself, but also by changing the distance between LED 34 and the first layer stack 10.

[0053] The duration of irradiation of the first laminate 10 (specifically, the coating layer 12) with light 14 is not particularly limited, but can be from 10 seconds to 1000 seconds, and may be 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 irradiation time with light 14 is, for example, 800 seconds or less, and may be 600 seconds or less depending on the circumstances. The irradiation with light 14 can be continuous or intermittent.

[0054] The cumulative light intensity of light 14 relative to the first layer stack 10 (specifically, coating layer 12) is, for example, 25 mJ / cm. 2 The above can be 100mJ / cm 2 Above 500mJ / cm 2 Above, 1000mJ / cm 2 Above, 2000mJ / cm 2 The above, and further, can be 3000 mJ / cm 2 That's all. There is no specific upper limit to the cumulative light output of light-14; for example, it could be 30,000 mJ / cm². 2 Below, 10000mJ / cm 2 The following, and further, can be 5000 mJ / cm 2 the following.

[0055] During the period when the first laminate 10 (specifically, coating layer 12) is irradiated by light 14, the temperature of coating layer 12 is, for example, below 50°C, preferably maintained at 10°C to 30°C. In this case, the curing speed of coating layer 12 can be appropriately adjusted, and there is a tendency for the number-average molecular weight and weight-average molecular weight of the polymer contained in adhesive sheet 1 to increase.

[0056] In the manufacturing method of this embodiment, the first laminate 10 (specifically, the coating layer 12) can also be irradiated with light 14 in a gas atmosphere with a reduced oxygen concentration compared to air (oxygen concentration 20.9 vol%). In this case, the curing of the coating layer 12 is less hindered by oxygen, and there is a tendency for the number-average molecular weight and weight-average molecular weight of the polymer contained in the adhesive sheet 1 to increase. Irradiation with light 14 can be performed in a gas 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. Irradiation with light 14 can also be performed in a gas atmosphere that substantially does not contain oxygen. A gas atmosphere with reduced oxygen concentration typically includes inert gases such as argon and nitrogen.

[0057] The manufacturing method of this embodiment may further include a heating step of heating the adhesive sheet 1 after irradiation with light 14. As an example, the heating step is performed on the third laminate 15 comprising the substrate sheet 11 and the adhesive sheet 1. Through the heating step, the drying and curing of the adhesive sheet 1 are promoted, and there is a tendency for the residual monomers contained in the adhesive sheet 1 to be further reduced.

[0058] The conditions for the heating process are not particularly limited and can be adjusted appropriately. As an example, the temperature of the heating process is preferably 40~200°C, more preferably 50~180°C, and even more preferably 70~170°C. The heating process time is, for example, 5 seconds to 20 minutes, preferably 5 seconds to 10 minutes, and more preferably 10 seconds to 5 minutes.

[0059] (Photocurable composition)

[0060] In this embodiment, the photocurable composition is an adhesive composition that forms an adhesive sheet 1 from the coating layer 12 by irradiation with light 14. The photocurable composition, for example, contains a monomer group containing (meth)acrylic acid monomers and / or a portion of the polymer of that monomer group. The content of the (meth)acrylic acid component in the photocurable composition, i.e., the (meth)acrylic acid monomer and its portion of the polymer, can be 50% by weight or more, 60% by weight or more, 70% by weight or more, and further, 80% by weight or more. In this case, an acrylic adhesive sheet 1 with (meth)acrylic acid polymer and its crosslinking as the main components can be formed. However, the photocurable composition is not limited to the above examples. In this specification, (meth)acrylic acid refers to acrylic acid and methacrylic acid. (Meth)acrylate refers to acrylate and methacrylate.

[0061] Examples of (meth)acrylic monomers are alkyl (meth)acrylates having an alkyl group having 1 to 20 carbon atoms in the side chain. The alkyl group may have 7 or fewer carbon atoms, 6 or fewer, 5 or fewer, and further, 4 or fewer. The alkyl group may be linear or branched. Examples of alkyl methacrylates are methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, isopentyl methacrylate, n-hexyl methacrylate, isohexyl methacrylate, isoheptyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, isooctyl methacrylate, n-nonyl methacrylate, isononyl methacrylate, n-decyl methacrylate, isodecyl methacrylate, n-dodecyl methacrylate (laurate methacrylate), n-tridecyl methacrylate, n-tetradecyl methacrylate, n-pentadecanyl methacrylate, n-hexadecyl methacrylate, hexadecyl methacrylate, heptadecanyl methacrylate, and octadecyl methacrylate. Alkyl methacrylates can be n-butyl methacrylates.

[0062] The content of alkyl (meth)acrylate in the monomer group can be, for example, 40% by weight or more, 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, and further, 95% by weight or more. It should be noted that when calculating the content, the weight of a portion of the polymer is converted to the weight of each monomer before polymerization.

[0063] The monomer group may include carboxyl-containing monomers. Carboxyl-containing monomers may be (meth)acrylic acid monomers; in other words, (meth)acrylic acid monomers may include carboxyl-containing monomers. Examples of carboxyl-containing monomers are (meth)acrylic acid, carboxyethyl (meth)acrylic acid, carboxypentyl (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, and crotonic acid. The content of carboxyl-containing monomers in the monomer group may be, for example, 10% by weight or less, but may be 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, and further may be 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, and further may be 1% by weight or more. The monomer group may also not contain carboxyl-containing monomers.

[0064] The monomer group may include hydroxyl-containing monomers. Hydroxyl-containing monomers may be (meth)acrylate monomers; in other words, (meth)acrylate monomers may include hydroxyl-containing monomers. Hydroxyl-containing monomers can contribute to improved cohesiveness of the adhesive sheet. Examples of hydroxyl-containing monomers 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 methyl (4-hydroxymethylcyclohexyl)acrylate. Preferably, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferred hydroxyl-containing monomers. The content of hydroxyl-containing monomers in the monomer group may be, for example, 10% by weight or less, but can 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, and further, 0.1% by weight or less. The lower limit of the content may be 0.01% by weight or more, 0.03% by weight or more, and further, 0.05% by weight or more. The monomer group may also not contain hydroxyl-containing monomers.

[0065] A monomer group may include nitrogen-containing monomers. A nitrogen-containing monomer is a monomer that has at least one nitrogen atom within a molecule (within one molecule).

[0066] From the viewpoint of improving foaming and peel resistance, N-vinylcyclic amides, (meth)acrylamides, etc., are preferred as nitrogen-containing monomers. It should be noted that nitrogen-containing monomers can be used alone or in combination of two or more.

[0067] N-vinyl cyclic amides are preferably represented by the following formula (1).

[0068] [Chemical Formula 1]

[0069]

[0070] In equation (1), R 1 It is a divalent organic group, preferably a divalent saturated hydrocarbon group or an unsaturated hydrocarbon group, more preferably a divalent saturated hydrocarbon group (e.g., an alkylene group with 3 to 5 carbon atoms). It should be noted that formula (1) represents N and R... 1 A ring structure is formed through direct bonding of single bonds.

[0071] 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-pyrazin-2-one, N-vinyl-3,5-morpholinedione, etc., are preferred, N-vinyl-2-pyrrolidone and N-vinyl-2-caprolactam are more preferred, and N-vinyl-2-pyrrolidone is even more preferred.

[0072] Examples of (meth)acrylamides include: (meth)acrylamide, N-alkyl (meth)acrylamide, N,N-dialkyl (meth)acrylamide, etc. Examples of N-alkyl (meth)acrylamides include: N-ethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-n-butyl (meth)acrylamide, N-octylacrylamide, etc. N-alkyl (meth)acrylamides also include (meth)acrylamides containing an amino group, such as dimethylaminoethyl (meth)acrylamide, diethylaminoethyl (meth)acrylamide, and dimethylaminopropyl (meth)acrylamide.

[0073] 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, N,N-di-tert-butyl(meth)acrylamide, etc.

[0074] (Methacrylamide) also includes, for example, various N-hydroxyalkyl (meth)acrylamides. Examples of N-hydroxyalkyl (meth)acrylamides include: N-hydroxymethyl (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, N-methyl-N-2-hydroxyethyl (meth)acrylamide, etc.

[0075] (Methacrylamide) also includes, for example, various N-alkoxyalkyl (meth)acrylamides. Examples of N-alkoxyalkyl (meth)acrylamides include, for example, N-methoxymethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, etc.

[0076] Examples of nitrogen-containing monomers other than N-vinylcyclic amides and (meth)acrylamide include: aminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, tert-butylaminoethyl (meth)acrylate, etc.; cyano monomers such as acrylonitrile and methacrylonitrile; (meth)acryloylmorpholine, N-vinylpiperazine, N-vinylpyrrole, N-vinylimidazolium, N-vinylpyrazine, N-vinylmorpholine, N-vinylpyrazole, vinylpyridine, vinylpyrimidine, vinylpyrazole, vinylisopyrazole, vinylthiazole, vinylisothiazole, vinylpyridazine, (meth)acryloylpyrrolidone, (meth)acryloylpyrrolidine, (meth)acryloylpiperidine, N-methylvinyl... Monomers containing heterocyclic compounds such as pyrrolidone; maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, and N-phenylmaleimide; itaconimide monomers such as N-methylitconimide, N-ethylitconimide, N-butylitconimide, N-octylitconimide, N-2-ethylhexylitconimide, N-laurylitconimide, and N-cyclohexylitconimide; succinimide monomers such as N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxohexamethylenesuccinimide, and N-(meth)acryloyl-8-oxooctamethylenesuccinimide; and isocyanate monomers such as 2-(meth)acryloyloxyethyl isocyanate.

[0077] The content of nitrogen-containing monomers in the monomer group is, for example, 40% by weight or less, 35% by weight or less, and further, 30% by weight or less. The lower limit of the content is, for example, 5% by weight or more, 7% by weight or more, and further, 10% by weight or more. The monomer group may also not contain nitrogen-containing monomers.

[0078] The aforementioned monomers may be included in the form of a partial polymer in the photocurable composition. The partial polymer may be any polymer among homopolymers and copolymers. The partial polymer can contribute to the stable formation of the coating layer 12 by moderately increasing the viscosity of the photocurable composition.

[0079] Photocurable compositions typically contain a photopolymerization initiator. Examples of photopolymerization initiators include photoradix generators that produce free radicals upon exposure to the aforementioned light 14. In photopolymerization initiators, the absorptivity relative to light with a wavelength of 340 nm is, for example, 0.1 L / (g·cm) or higher, and can be 0.5 L / (g·cm) or higher, 1.0 L / (g·cm) or higher, 3.0 L / (g·cm) or higher, and further, 5.0 L / (g·cm) or higher. There is no particular upper limit to this absorptivity, and it is, for example, 50 L / (g·cm) or lower. The absorptivity of the photopolymerization initiator is calculated using a quartz cell with an optical path length of 1 cm, from the absorbance of a 0.01 mg / mL methanol solution measured using a visible-ultraviolet spectrophotometer.

[0080] Examples of photopolymerization initiators include benzoin methyl ether, benzoin isopropyl ether, benzoin dimethyl ether, and other benzoin ethers; substituted benzoin ethers such as anisole methyl ether; substituted acetophenones such as 2,2-diethoxyacetophenone and 2,2-dimethoxy-2-phenylacetophenone; 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methylphenylacetone, 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, and 2,2'-dihydroxy-2,2'-dimethyl-1,1'-[methylenebis(4,1] α-hydroxyalkyl phenyl ketones such as bis(propane-1-one); substituted α-ol ketones such as 2-methyl-2-hydroxyphenylacetone; aromatic sulfonyl chlorides such as 2-naphthalenesulfonyl chloride; photoactive oximes such as 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime; benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3',4,4'-tetra(tert-butyl) Benzophenone compounds such as carbonyl peroxide (BPK); thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, 2,4-diethylthioxanthone, and other thioxanthone compounds; 2,4,6-trichloro-triazine, 2-phenyl-4,6-bis(trichloromethyl)-triazine, 2-(p-methoxyphenyl)-4,6-bis(trichloromethyl)-triazine, 2-(p-tolyl)-4,6-bis(trichloromethyl)-triazine, 2-piperyl-4 Triazine compounds such as 6-bis(trichloromethyl)-triazine, 2,4-bis(trichloromethyl)-6-styryl-triazine, 2-(naphthyl-1-yl)-4,6-bis(trichloromethyl)-triazine, 2-(4-methoxy-naphthyl-1-yl)-4,6-bis(trichloromethyl)-triazine, 2,4-trichloromethyl-(piperyl)-6-triazine, and 2,4-trichloromethyl-(4'-methoxystyryl)-6-triazine; 1,2-octanedione, 1-[4-(phenylthio)-, The photocurable composition may contain one or more photopolymerization initiators. In particular, α-hydroxyalkyl phenyl esters such as 2-(O-benzoyl oxime) and O-(acetyl)-N-(1-phenyl-2-oxo-2-(4'-methoxy-naphthyl)ethoxy)hydroxylamine; phosphine compounds such as bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2,4,6-trimethylbenzoyl diphenylphosphine oxide; quinone compounds such as 9,10-phenanthroquinone, camphorquinone, and ethylanthraquinone; borate esters; carbazole compounds; imidazole compounds; and titanium ether compounds. The photocurable composition may contain one or more photopolymerization initiators. In particular, α-hydroxyalkylphenyl ketones tend to have high absorption of light with wavelengths of 325 nm to 350 nm, making them suitable for the manufacturing method of this embodiment.

[0081] The amount of photopolymerization initiator in the photocurable composition is, for example, 20 parts by weight or less, relative to 100 parts by weight of the monomer group and a portion of the polymer, and can 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, and further, 0.3 parts by weight or less. When the amount of photopolymerization initiator is 1.0 parts by weight or less, there is a tendency for the weight-average molecular weight of the polymer contained in the adhesive sheet 1 to be sufficiently high. The lower limit of the amount of photopolymerization initiator relative to 100 parts by weight of the monomer group and a portion of the polymer is, for example, 0.02 parts by weight or more, and can be 0.05 parts by weight or more.

[0082] The photocurable composition may contain a crosslinking agent. Examples of crosslinking agents are polyfunctional monomers having two or more polymerizable functional groups in one molecule. The polyfunctional monomer may be a (meth)acrylic acid monomer. Examples of polyfunctional monomers include monomers having two or more C=C bonds in one molecule, and monomers having one or more C=C bonds and one or more polymerizable functional groups such as epoxy, aziridinyl, α-azolinyl, hydrazyl, and hydroxymethyl in one molecule. Preferably, the polyfunctional monomer is a monomer having two or more C=C bonds in one molecule.

[0083] Examples of multifunctional monomers include: polyethylene glycol di(meth)acrylate, polypropylene 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 (NDDA), 1,12-dodecanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, and other multifunctional acrylates (ester compounds formed by polyols and (meth)acrylic acid, etc.); allyl methacrylate, vinyl methacrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyl di(meth)acrylate, and hexyl di(meth)acrylate. The multifunctional monomer is preferably a multifunctional acrylate, more preferably 1,9-nonanediol diacrylate, trimethylolpropane tri(meth)acrylate, hexanediol di(meth)acrylate, or dipentaerythritol hexa(meth)acrylate.

[0084] The amount of crosslinking agent varies depending on the molecular weight, number of functional groups, etc., but relative to the total of 100 parts by weight of the monomer group and some of the polymer, it is, for example, 5 parts by weight or less, and can be 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, and further can be 0.3 parts by weight or less. The lower limit of the amount is, for example, 0.01 parts by weight or more, and further can be 0.05 parts by weight or more.

[0085] The photocurable composition may also contain additives other than those mentioned above. Examples of additives include chain transfer agents, silane coupling agents, viscosity modifiers, tackifiers, plasticizers, softeners, anti-aging agents, fillers, colorants, antioxidants, surfactants, antistatic agents, and UV absorbers.

[0086] The solvent content in the photocurable composition is, for example, 5% by weight or less, and can be 4% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, and further, 0.5% by weight or less. The photocurable composition may substantially not contain solvent. Substantially not containing solvent means that it is permissible to include solvents from additives or the like at a content of, for example, 0.1% by weight or less, preferably 0.05% by weight or less, more preferably 0.01% by weight or less.

[0087] The viscosity of the photocurable composition is preferably 1 to 100 poise. Photocurable compositions with viscosities within the above range are particularly suitable for the formation of coating layer 12.

[0088] (Peel-off liner)

[0089] An example of a substrate (hereinafter, "substrate") for peeling off liner 13 is a resin film. Examples of resins that may be included in the substrate include polyesters such as polyethylene terephthalate and polyethylene naphthalate, acetate resins, polyethersulfone, polycarbonate, polyamide, polyimide, polyolefin, (meth)acrylic resin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl alcohol, polyarylate, and polyphenylene sulfide. The resin is preferably a polyester such as polyethylene terephthalate.

[0090] The release liner 13 can be transmissive to light 14. For example, the spectral transmittance of the release liner 13 relative to light with a wavelength of 340 nm is, for example, 60% or more, 70% or more, and further, 80% or more. There is no particular upper limit to the spectral transmittance; for example, it can be 95% or less, or 90% or less. The spectral transmittance relative to light with a wavelength of 340 nm can be determined, for example, by measuring the total transmittance spectrum of the release liner 13 in the wavelength range of 300 to 2000 nm using a commercially available spectrophotometer, and the result is determined from the obtained spectrum.

[0091] The thickness of the peeling liner 13 is, for example, 10~200μm, or 25~150μm.

[0092] The release liner 13 may also have layers other than the substrate. The release liner 13 may have a release layer. For example, the release liner 13 may have a substrate and a release layer formed on one side of the substrate. The release liner 13 may be used such that the release layer is on the side of the coating layer 12.

[0093] Typically, the release layer is a cured layer of a release agent composition containing a release agent. Various release agents can be used, such as silicone-based release agents, fluorinated release agents, long-chain alkyl-based release agents, fatty acid amide-based release agents, and silica powder. The release liner 13 may have a cured layer (hereinafter, "silicone release layer") of a release agent composition containing a silicone-based release agent as the main component. The silicone release layer is particularly suitable for balancing adhesion and peelability relative to the adhesive sheet 1. It should be noted that, in this specification, the main component refers to the component with the highest content.

[0094] Organosilicon release agents include various curing types of organosilicon materials, such as addition reaction type, condensation reaction type, UV curing type, electron beam curing type, and solvent-free type, with addition reaction curing type organosilicon materials being preferred. Addition reaction curing type organosilicon materials are particularly suitable for forming a release layer that balances adhesion and peelability relative to the adhesive sheet 1. The curing type organosilicon material can be an organosilicon-modified resin obtained by introducing reactive organosilicon into organic resins such as urethane, epoxy, and alkyd resins through graft polymerization or the like.

[0095] Examples of addition-reaction-curable silicone materials are polyorganosiloxanes containing vinyl or alkenyl groups within the molecule. Addition-reaction-curable silicone materials may also lack hydrogenated silyl groups. Examples of alkenyl groups include 3-butenyl, 4-pentenyl, 5-hexenyl, 6-heptenyl, 7-octenyl, 8-nonenyl, 9-decenyl, 10-undecenyl, and 11-dodecenyl. Examples of polyorganosiloxanes include polyalkylalkylsiloxanes such as polydimethylsiloxane, polydiethylsiloxane, and polymethylethylsiloxane, polyalkylarylsiloxanes, and copolymers of various Si-containing monomers such as poly(dimethylsiloxane-diethylsiloxane). Polyorganosiloxanes are preferably polydimethylsiloxane.

[0096] Release agent compositions containing silicone-based release agents as the main component (hereinafter, "silicone release agent compositions") typically contain crosslinking agents. Examples of crosslinking agents are polyorganosiloxanes having hydrogenated silyl groups. Crosslinking agents may have two or more hydrogenated silyl groups in one molecule.

[0097] Organosilicon release agent compositions may also contain curing catalysts. Examples of curing catalysts are platinum-based catalysts. Examples of platinum-based catalysts include chloroplatinic acid, platinum olefin complexes, and chloroplatinic acid olefin complexes. The amount of platinum-based catalyst relative to the total solids content of the composition is, for example, 10 to 1000 ppm (by weight, converted to platinum).

[0098] The silicone release agent composition may also contain additives. Examples of additives are peel control agents and adhesion improvers. Examples of peel control agents are unreactive silicone resins, more specifically, organosiloxanes such as octamethylcyclotetrasiloxane and MQ resins. The amount of peel control agents and adhesion improvers, in total, is, for example, 1 to 30% by weight relative to the total solids content of the composition. Other examples of additives are fillers, antistatic agents, antioxidants, UV absorbers, plasticizers, and colorants. The amount of other additives, in total, is, for example, less than 10% by weight relative to the total solids content of the composition.

[0099] The silicone release agent composition may also contain organic solvents. Examples of organic solvents 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 also be included. The preferred amount of organic solvent is 80-99.9% by weight of the silicone release agent composition.

[0100] A release layer can be formed, for example, by heating and drying a coating film containing a release agent composition formed on a substrate. The release agent composition can be applied using various methods such as roller coating, licking coating, gravure coating, reverse coating, brush coating, spraying, dip roller coating, bar coating, doctor blade coating, air knife coating, curtain coating, die lip coating, and die coating. Heating and drying can be performed using hot air drying, for example. The heating temperature and time vary depending on the heat resistance of the substrate, typically ranging from 80 to 150°C for approximately 10 seconds to 10 minutes. If necessary, irradiation with active energy rays such as ultraviolet light can also be used in combination.

[0101] The thickness of the release layer is, for example, 10~300nm. The upper limit of the thickness can be below 200nm, below 150nm, below 120nm, below 110nm, below 100nm, less than 100nm, below 90nm, below 80nm, below 70nm, less than 70nm, and further below 65nm. The lower limit of the thickness can be above 15nm, above 20nm, above 25nm, above 30nm, above 35nm, above 40nm, above 45nm, and further above 50nm.

[0102] The peeling liner 13 can be in the form of a single sheet or in the form of a strip.

[0103] (Substrate sheet)

[0104] An example of substrate sheet 11 is a resin film. Examples of resins contained in substrate sheet 11 are the same as examples of resins that may be contained in a liner substrate.

[0105] The preferred substrate 11 exhibits excellent light transmittance to the light 14. For example, the spectral transmittance of the substrate 11 relative to light with a wavelength of 340 nm is, for instance, 60% or more, 70% or more, and further, 80% or more. The higher the spectral transmittance, the more effectively the coating layer 12 can be cured by the light 14. Furthermore, it can suppress the substrate 11 from absorbing light 14 and generating heat. There is no particular upper limit to the spectral transmittance; for example, it can be 95% or less, or 90% or less. The spectral transmittance relative to light with a wavelength of 340 nm can be determined using the method described above for the release liner 13.

[0106] The thickness of the substrate sheet 11 is, for example, 10~200μm, or 25~150μm.

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

[0108] The substrate sheet 11 can typically be selected as a sheet with a greater peel force to the adhesive sheet 1 compared to the release liner 13.

[0109] The substrate sheet 11 can be a single sheet or a strip.

[0110] (First layer of stack and its formation)

[0111] The first layer stack 10 may also include additional layers besides the substrate sheet 11, the coating layer 12, and the release liner 13. These additional layers may be disposed on the side of the substrate 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 substrate sheet 11 and the release liner 13.

[0112] The first laminate 10 can be formed, for example, by forming a coating layer 12 on a substrate sheet 11 (or release liner 13) and placing a release liner 13 (or substrate sheet 11) on the formed coating layer 12. Alternatively, the first laminate 10 can be formed by coating in such a way that a photocurable composition flows into a space between a substrate sheet 11 and a release liner 13 held at a given interval with their main surfaces facing each other.

[0113] The coating layer 12 can be formed by various coating methods such as roller coating, roller licking coating, gravure coating, reverse coating, roller brushing, spraying, dip roller coating, bar coating, scraping coating, air knife coating, curtain coating, die lip coating, and die coating.

[0114] The thickness of the coating layer 12 can be adjusted according to the thickness of the target adhesive sheet 1, for example, less than 2 mm, less than 1 mm, 2~300 μm, 2~200 μm, 2~150 μm, 2~100 μm, 2~70 μm, 2~50 μm, 5~40 μm, 10~30 μm, 10~25 μm, and further, 10~20 μm.

[0115] The first laminate 10 may include a strip-shaped substrate sheet 11, a strip-shaped coating layer 12, and a strip-shaped release liner 13; in other words, it may be strip-shaped. The strip-shaped first laminate 10 may be obtained, for example, by forming the coating layer 12 between the substrate sheet 11 and the release liner 13 while they are being continuously fed from the winding body.

[0116] (Adhesive sheet)

[0117] As described above, the adhesive sheet 1 manufactured using the manufacturing method of this embodiment tends to have a low residual amount of photopolymerization initiator. Adhesive sheet 1 with a low residual amount of photopolymerization initiator tends to exhibit suppressed yellowing and bubbling in high-temperature environments. For example, the content of photopolymerization initiator in adhesive sheet 1 may be 500 wtppm or less, and could be 300 wtppm or less, 200 wtppm or less, 150 wtppm or less, 120 wtppm or less, 100 wtppm or less, 80 wtppm or less, 50 wtppm or less, or even 30 wtppm or less. Adhesive sheet 1 may substantially not contain any photopolymerization initiator.

[0118] Furthermore, the adhesive sheet 1 manufactured using the manufacturing method of this embodiment tends to have a high polymerization rate of monomer groups and a low residual amount of monomer groups. Adhesive sheet 1 with a low residual amount of monomer groups not only tends to contribute to improved productivity but also suppresses odor. This adhesive sheet 1 also has the advantages of good handling and easy transport. The polymerization rate of the monomer groups in the adhesive sheet 1 is preferably 80% or more, and can be 85% or more, 90% or more, 95% or more, 97% or more, 98% or more, and further, 99% or more.

[0119] According to the manufacturing method of this embodiment, there is a tendency for the polymer contained in the adhesive sheet 1 to have a large molecular weight. As an example, when the manufacturing method of this embodiment is performed using a sample having the same composition as the aforementioned photocurable composition except for the absence of a crosslinking agent, the weight-average molecular weight (Mw) of the polymer obtained by polymerizing the monomer group contained in the sample is, for example, 400,000 or more, and can be 500,000 or more, 700,000 or more, 800,000 or more, 900,000 or more, and further, 1,000,000 or more. The larger this Mw is, the greater the tendency for peeling of the adhesive sheet 1 to be suppressed, such as in high-temperature environments. There is no particular upper limit to Mw, for example, it is 3,000,000 or less. It should be noted that the number-average molecular weight (Mn) of the aforementioned polymer is, for example, 80,000 or more, and can be 100,000 or more, 150,000 or more, 180,000 or more, 200,000 or more, and further, 250,000 or more. There is no particular upper limit to Mn, for example, it is 600,000 or less. The weight-average molecular weight (Mw) / number-average molecular weight (Mn), which represents the molecular weight distribution, is, for example, 1.8 to 10, and can be 1.8 to 7, or even 1.8 to 5. The weight-average molecular weight and number-average molecular weight can be obtained by measuring them using GPC (gel permeation chromatography) and calculating them using polystyrene conversion.

[0120] The gel fraction of adhesive sheet 1 is, for example, 50% or more, 75% or more, 80% or more, and even 85% or more.

[0121] The thickness of the adhesive sheet 1 can be less than 2 mm, or less than 1 mm, 2~300 μm, 2~200 μm, 2~150 μm, 2~100 μm, 2~70 μm, 2~50 μm, 5~40 μm, 10~30 μm, 10~25 μm, and even 10~20 μm.

[0122] The adhesive sheet 1 manufactured using the method of this embodiment is particularly suitable for applications requiring high light transmittance (e.g., optical applications). However, the adhesive sheet 1 can also be used for various applications other than optical applications. The adhesive sheet 1 can also be used in double-sided tapes.

[0123] Next, refer to Figure 2Another example of the method for manufacturing the adhesive sheet will be described. In this example, a coating layer 12 of a photocurable composition is formed on one side of a strip-shaped substrate sheet 11 continuously released from a winding body 31 by a coating apparatus 32. Next, a strip-shaped release liner 13 continuously released from a winding body 33 is disposed on the coating layer 12 to form a strip-shaped first laminate 10. Next, the first laminate 10 is irradiated with light 14 by an LED 34 to form a strip-shaped adhesive sheet 1. Next, the release liner 13 is peeled off from a second laminate 17 containing the adhesive sheet 1 and wound onto a winding body 35. The above steps are performed while the substrate sheet 11 and the release liner 13 are being transported. Figure 2 This method is particularly suitable for the mass production of adhesive sheets.

[0124] Next, refer to Figure 3 Another example of a method for manufacturing an adhesive sheet will be described. In this example, a photocurable composition is coated using a coating apparatus 32 between a strip-shaped substrate sheet 11 continuously released from a winding body 31 and a strip-shaped release liner 13 continuously released from a winding body 33. This forms a coating layer 12 containing the photocurable composition, resulting in a strip-shaped first laminate 10.

[0125] Next, the first laminate 10 is transported between a pair of light sources 38A and 38b. Specifically, firstly, the first laminate 10 passes through a first region 40A near the light source 38A. Next, using a first reversing mechanism (first transport roller 39A), the movement direction of the first laminate 10 is reversed, moving it in the opposite direction to its movement in the first region 40A. This causes the first laminate 10 to pass through a second region 40B, which is closer to the light source 38b than the first region 40A. Next, using a second reversing mechanism (second transport roller 39b), the movement direction of the first laminate 10 is further reversed, moving it in the same direction as its movement in the first region 40A. This causes the first laminate 10 to pass through a third region 40C near the light source 38b.

[0126] Typically, light source 38A is an LED that illuminates light L1 with a peak wavelength of 325nm to 350nm. Similarly, typically, light source 38b is an LED that illuminates light L2 with a peak wavelength of 325nm to 350nm. The aforementioned LED 34 can be used as light sources 38A and 38b.

[0127] exist Figure 3In the example, the sum of the illuminance of light L1 from the release liner 13 side and the illuminance of light L2 from the substrate sheet 11 side in the first region 40A (illuminance LA), the sum of the illuminance of light L1 from the substrate sheet 11 side and the illuminance of light L2 from the release liner 13 side in the second region 40B (illuminance LB), and the sum of the illuminance of light L1 from the release liner 13 side and the illuminance of light L2 from the substrate sheet 11 side in the third region 40C (illuminance LC) are preferably adjusted to 2.0~30mW / cm². 2 The illuminance LA~LC can satisfy the relationship LA < LB < LC. The illuminance LA~LC can be adjusted according to the position and output of light sources 38A and 38b. As an example, it can be adjusted so that the distance between light source 38A and the first region 40A is greater than the distance between light source 38b and the third region 40C.

[0128] Light L1 and L2, with peak wavelengths of 325 nm to 350 nm, are irradiated onto the coating layer 12 by passing between a pair of light sources 38A and 38b, thereby forming a strip-shaped adhesive sheet 1. Next, a release liner 13 is peeled off from the second laminate 17 containing the adhesive sheet 1 and wound onto a winding body 35. Using... Figure 3 This method allows for the formation of adhesive sheets in a small space, making it particularly suitable for the mass production of adhesive sheets.

[0129] It should be noted that, in Figure 3 In the example, the polymerization rate of the monomer group at the time point after passing through the first region 40A is preferably 50% or more. In this case, when the movement direction of the first laminate 10 is reversed by the first reversing mechanism (first conveying roller 39A), there is a tendency for the components constituting the first laminate 10 to be less prone to appearance defects such as wrinkles, stripes, and floats.

[0130] [Manufacturing method of optical film with adhesive sheet]

[0131] Reference Figure 4 An example of a method for manufacturing an optical film with an adhesive sheet according to this embodiment will be described. Figure 4 In one example, an optical film 21 with an adhesive sheet is formed by placing an optical film 2 on the exposed surface 18 of an adhesive sheet 1 formed by peeling off a release liner 13 from a second laminate 17 produced using the above method. It should be noted that a surface modification treatment may also be performed on the exposed surface 18 of the adhesive sheet 1 before placing the optical film 2.

[0132] The optical film 21 with adhesive sheet sequentially comprises a substrate sheet 11, an adhesive sheet 1, and an optical film 2. The optical film 21 with adhesive sheet can be used directly, or after peeling off the substrate sheet 11, for example, in the form of an optical laminate comprising an adhesive sheet 1 and an optical film 2, in an image display device, etc. The optical laminate can be attached to an object (e.g., an image forming panel) via the adhesive sheet 1. However, it should be noted that the application of the optical film 21 with adhesive sheet is not limited to the above examples. Other components, such as an optical film, can also be disposed on the exposed surface 18 formed by peeling the substrate sheet 11 from the optical film 21 with adhesive sheet. As an example, an optical film 22 with adhesive sheet sequentially comprising an optical film 2A, an adhesive sheet 1, and an optical film 2B can be formed (see [reference]). Figure 5 Optical films 2A and 2B can be the same or different from each other.

[0133] The optical film 2 can be configured directly or indirectly toward the exposed surface 18. In other words, the optical film 2 can be configured to be in contact with the exposed surface 18, or it can be configured to have other layers sandwiched between it and the exposed surface 18.

[0134] Reference Figure 6 Another example of the method for manufacturing the optical film with an adhesive sheet according to this embodiment will be described. In this example, when... Figure 2 In the third laminate 15 formed by this method, an elongated optical film 2 is disposed on the exposed surface 18 of the adhesive sheet 1, forming an elongated optical film 21 with the adhesive sheet. The optical film 2 is continuously released from the winding body 36 and disposed on the exposed surface 18. Figure 6 As shown, the formation of the adhesive sheet 1 and the formation of the optical film 21 with the adhesive sheet can be carried out continuously. Figure 6 This method is particularly suitable for the mass production of optical films 21 with adhesive sheets.

[0135] Optical film 2 may be, for example, a film comprising at least one selected from polarizing films and retardation films. Optical film 2 may be a laminated film comprising polarizing films and / or retardation films. Optical film 2 may also comprise a glass film. However, optical film 2 is not limited to the examples described above.

[0136] A polarizing film includes a polarizer. Typically, a polarizing film includes a polarizer and a protective film (a transparent protective film). The protective film is disposed in contact with the ground, for example, the main surface (the surface with 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 side of the polarizer.

[0137] There are no particular limitations on what constitutes a polarizer. Examples include: polarizers obtained by uniaxially stretching hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and partially saponified ethylene-vinyl acetate copolymer films, after adsorbing dichroic substances such as iodine and dichroic dyes onto them; and polyene-oriented films such as dehydrated polyvinyl alcohol products and dehydrochlorinated polyvinyl chloride products. Typically, a polarizer is formed from a polyvinyl alcohol film (which may contain partially saponified ethylene-vinyl acetate copolymer films) and dichroic substances such as iodine.

[0138] The thickness of the polarizer is not particularly limited; for example, it can be less than 80 μm, less than 50 μm, less than 30 μm, less than 25 μm, and even less than 20 μm. The lower limit of the polarizer's thickness is not particularly limited; for example, it can be greater than 1 μm, greater than 5 μm, greater than 10 μm, and even greater than 15 μm. For thin polarizers (e.g., less than 20 μm thick), dimensional changes are suppressed, which can contribute to the improved durability of the optical laminate, especially its durability at high temperatures.

[0139] As materials for the protective film, thermoplastic resins with excellent properties such as transparency, mechanical strength, thermal stability, moisture barrier properties, and isotropy can be used. Specific examples of such thermoplastic resins include cellulose resins such as cellulose triacetate, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, cyclic polyolefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. The protective film material can be thermosetting resins or UV-curable resins such as (meth)acrylic acid, urethane, acrylate urethane, epoxy, and silicone. In the case where the polarizing film has two protective films, the materials of the two protective films can be the same or different. For example, a protective film formed of thermoplastic resin can be bonded to one main surface of the polarizer via an adhesive, and a protective film formed of thermosetting resin or UV-curable resin can be bonded to the other main surface of the polarizer. The protective film can contain one or more arbitrary additives. Examples of additives include: ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, and colorants.

[0140] The thickness of the protective film can be appropriately determined. Generally speaking, it is about 10~200μm, considering factors such as strength, processability, operability, and thinness.

[0141] Polarizing lenses and protective films are typically bonded together using water-based adhesives. Examples of water-based adhesives include isocyanate adhesives, polyvinyl alcohol adhesives, gelatin adhesives, vinyl latexes, waterborne polyurethane, and waterborne polyester. Other adhesives besides those mentioned above include UV-curable adhesives and electron beam-curable adhesives. Electron beam-curable polarizer adhesives exhibit suitable adhesion to various protective films. The adhesive may also contain metallic compound fillers.

[0142] In polarizing films, a phase retardation film or similar material can be formed on the polarizer to replace the protective film. Furthermore, additional protective films or phase retardation films can be added on top of the protective film.

[0143] Regarding the protective film, a hard coating can also be applied to the surface opposite to the surface to which the polarizer is bonded, and it can also be treated for purposes such as anti-reflection, anti-adhesion, diffusion, and anti-glare.

[0144] The polarizing film can be a circularly polarizing film.

[0145] As a retardation film, films obtained by stretching a polymer film or by aligning and immobilizing a liquid crystal material can be used. Retardation films, for example, exhibit birefringence in the in-plane and / or thickness directions.

[0146] Phase retardation films include anti-reflective phase retardation films (see Japanese Patent Application Publication No. 2012-133303

[0221] ,

[0222] ,

[0228] ), viewing angle compensation phase retardation films (see Japanese Patent Application Publication No. 2012-133303

[0225] ,

[0226] ), and tilt-oriented phase retardation films for viewing angle compensation (see Japanese Patent Application Publication No. 2012-133303

[0227] ), etc.

[0147] There are no particular limitations on the specific composition of the retardation film, such as the phase difference value, the configuration angle, the three-dimensional birefringence, whether it is a single layer or a multilayer, and known retardation films can be used.

[0148] The thickness of the phase retardation film is preferably 20 μm or less, more preferably 10 μm or less, even more preferably 1 to 9 μm, and particularly preferably 3 to 8 μm.

[0149] Phase retardation films may include, for example, quarter-wave plates and / or half-wave plates obtained by aligning and immobilizing liquid crystal materials.

[0150] [Manufacturing Method of Image Display Device]

[0151] An image display device can be formed using an optical film with an adhesive sheet formed by the above-described manufacturing method. For example, the image display device can be formed by bonding the optical films 21 and 22 with adhesive sheets to an image display panel. Bonding can be performed using the adhesive sheet 1. The image display device can be an organic EL display or a liquid crystal display. However, the image display device is not limited to the examples described above. The image display device can also be an electroluminescent (EL) display, a plasma display (PD), a field emission display (FED), etc. The image display device can be used for home appliances, automotive applications, public information displays (PIDs), etc.

[0152] Example

[0153] The present invention will now be described in more detail through embodiments. The present invention is not limited to the embodiments shown below.

[0154] [Monomeric slurry A1]

[0155] 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-hydroxycyclohexylphenyl ketone (Omnirad 184, manufactured by IGM Resins BV) and 0.05 parts by weight of 2,2-dimethoxy-1,2-diphenylethane-1-one (Omnirad 651, manufactured by IGM Resins BV) as photopolymerization initiators were added to a four-necked flask and irradiated with ultraviolet light in a nitrogen atmosphere, thereby obtaining a monomer slurry A1 after partial photopolymerization. The ultraviolet irradiation 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.

[0156] [Single slurry A2~A9]

[0157] The monomers used were changed as shown in Table 1. Otherwise, monomer slurries A2 to A9 were prepared using the same method as monomer slurry A1.

[0158]

[0159] The abbreviations in Table 1 are as follows.

[0160] BA: n-Butyl acrylate

[0161] AA: Acrylic acid

[0162] HBA: 4-Hydroxybutyl acrylate

[0163] OmnirAd184: 1-Hydroxycyclohexyl-phenyl ketone (OmnirAd184, manufactured by IGM Resins BV)

[0164] OmnirAd651: 2,2-Dimethoxy-1,2-diphenylethane-1-one (OmnirAd651, manufactured by IGM Resins B.V.)

[0165] OmnirAd819: Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (OmnirAd819, manufactured by IGM Resins B.V.)

[0166] OmnirAd127: 2-Hydroxy-1-(4-(4-(2-hydroxy-2-methylpropanoyl)benzyl)phenyl)2-methylpropane-1-one (OmnirAd127, manufactured by IGM Resins BV)

[0167] OmnirAd2959: 2-Hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone (OmnirAd2959, manufactured by IGMresins BV)

[0168] [Photocurable compositions C1~C13]

[0169] Next, the monomer slurry, monomer, and crosslinking agent were mixed to achieve the compositions shown in Table 2 below, resulting in photocurable compositions C1~C13.

[0170]

[0171] The abbreviations in Table 2 are as follows.

[0172] AA: Acrylic acid

[0173] NVP: N-vinyl-2-pyrrolidone

[0174] NDDA: 1,9-Nonadiol diacrylate

[0175] The final composition of the monomers contained in the photocurable compositions C3 and C4 is shown in Table 3 below.

[0176]

[0177] The abbreviations in Table 3 are as follows.

[0178] BA: n-Butyl acrylate

[0179] AA: Acrylic acid

[0180] HBA: 4-Hydroxybutyl acrylate

[0181] NVP: N-vinyl-2-pyrrolidone

[0182] (Example 1)

[0183] [Fabrication of stripped liner L1]

[0184] A silicone-based release agent composition was prepared by mixing 30 parts by weight of an addition-reaction curable silicone (containing LTC761 with hexenyl polysiloxane, 30% toluene solution, manufactured by Toray Dow Corning), 0.9 parts by weight of a release control agent (containing unreactive silicone resin BY24-850, manufactured by Toray Dow Corning), 2 parts by weight of a curing catalyst (containing platinum catalyst SRX212, manufactured by Toray Dow Corning), and a toluene / hexane mixed solvent (volume ratio 1:1) as a diluent. The concentration of the silicone solid component in the release agent composition was 1.0% by weight. Next, the release agent composition was coated onto one side of a substrate (Lumirror XD500P polyester film, 75 μm thick) using a wire rod, and heated at 130°C for 1 minute to produce a release liner L1 with a release layer (60 nm thick) on one side.

[0185] [Making the Adhesive Sheet]

[0186] A photocurable composition C1 was applied to one side of a substrate sheet (a Lumirror XD500P polyester film without a release layer, 75 μm thick) using an applicator, forming a coating layer (20 μm thick). Next, a release liner L1 was placed on the formed coating layer to obtain the first laminate. The release liner L1 was positioned such that the release layer was in contact with the coating layer. Next, an illuminance of 4 mW / cm² was applied. 2 Light from an LED was irradiated from one side of the substrate sheet of the first laminate for 640 seconds. The peak wavelength of the light was 340 nm. The irradiation was performed at room temperature (23°C). As a result, the coating layer was photocured, resulting in the adhesive sheet (20 μm thick) of Example 1 sandwiched between the substrate sheet and the release liner L1. It should be noted that the illuminance was measured using an illuminance meter (TOPCON TECHNOHOUSE, UD-T3040T2).

[0187] (Examples 2-13 and Comparative Examples 1-3)

[0188] The photocurable composition, light source, and light irradiation conditions used were modified as shown in Table 4. Otherwise, adhesive sheets of Examples 2-13 and Comparative Examples 1-3, held between a substrate sheet and a release liner L1, were obtained using the same method as in Example 1. It should be noted that in Examples 10-13, an LED with a peak wavelength of 330 nm was used as the light source. In Comparative Examples 1-3, a black light source (B / L) was used as the light source.

[0189] [Residual amount of photopolymerization initiator]

[0190] The composition of the adhesive sheets prepared in Examples 1-13 and Comparative Examples 1-3 was analyzed, and the residual amount (content) of the photopolymerization initiator was calculated based on the results. It should be noted that the composition analysis was performed using liquid chromatography (LC) under the following conditions.

[0191] • Device used: 1290 Infinity II (manufactured by Agilent Technologies)

[0192] • Chromatographic column: Acquity UPLC BEH C18 (Waters, 2.1mm φ × 100mm, 1.7μm)

[0193] • Eluent composition: Gradient conditions of ultrapure water / acetonitrile

[0194] Column temperature: 40℃

[0195] • Column flow rate: 0.2 mL / min

[0196] Injection volume: 2μL

[0197] • Detector: Photodiode Array Detector (PDA)

[0198] • Measurement wavelength: 190~400nm

[0199] ·Extraction wavelength: OmnirAd184=246nm, OmnirAd651=253nm, OmnirAd819=296nm, OmnirAd127=262nm, OmnirAd2959=278nm

[0200] • Sample preparation method: Weigh approximately 0.5 g of the sample (adhesive sheet), add 2 mL of chloroform, and shake overnight. Add 8 mL of methanol to the resulting solution, and filter the supernatant through a 0.45 μm membrane filter. Inject the filtrate into an LC filter for analysis.

[0201] [Polymerization rate of monomer group]

[0202] For the adhesive sheets prepared in Examples 1-13 and Comparative Examples 1-3, the polymerization rate of the monomer group was determined by the following method. First, the substrate sheet and release liner were peeled off from the adhesive sheet, and the weight W0 (weight before drying) of the adhesive sheet was measured. Next, the adhesive sheet was heated and dried at 130°C for 2 hours, then cooled at room temperature (23°C) for about 20 minutes, and the weight W1 (weight after drying) of the adhesive sheet was measured. Based on the weights W0 (g) and W1 (g), the polymerization rate of the monomer group was calculated using the following formula.

[0203] Polymerization rate (%) = W1 / W0 × 100

[0204] [Number-average molecular weight (Mn) and weight-average molecular weight (Mw) of the polymer]

[0205] First, samples were prepared having the same composition as the photocurable compositions used in Examples 1-13 and Comparative Examples 1-3, except that they did not contain a crosslinking agent. The samples were then irradiated with light under the conditions of the corresponding examples and comparative examples. As a result, the monomer groups contained in the samples polymerized to form a polymer. The number-average molecular weight (Mn) and weight-average molecular weight (Mw) of this polymer were measured.

[0206] The Mn and Mw were determined by GPC (gel permeation chromatography). The apparatus and conditions are described below. It should be noted that the apparatus and conditions differed for compositions containing NVP and compositions without NVP.

[0207] (Components excluding NVP)

[0208] ·Analysis device: Made by Tosoh Corporation, HLC-8120GPC

[0209] • Chromatographic column: Tosoh Corporation, G7000H XL +GMH XL +GMH XL

[0210] • Column dimensions: 7.8mm φ × 30cm each, totaling 90cm

[0211] Column temperature: 40℃

[0212] • Flow rate: 0.8 mL / min

[0213] Injection volume: 100μL

[0214] • Eluent: Tetrahydrofuran

[0215] • Detector: Differential refractometer (RI)

[0216] Standard sample: polystyrene

[0217] (Composition containing NVP)

[0218] • Analytical apparatus: Agilent Technologies, Agilent 1200

[0219] • Chromatographic column: Tosoh Corporation, TSKgel SuperAWM-H + superAW4000 + superAW2500

[0220] • Column dimensions: 6.0mm φ × 15cm each, totaling 45cm

[0221] Column temperature: 40℃

[0222] • Flow rate: 0.4 mL / min

[0223] Injection volume: 40μL

[0224] • Eluent: N,N-Dimethylformamide (DMF)

[0225] • Detector: Differential refractometer (RI)

[0226] Standard sample: polystyrene

[0227]

[0228] Table 4 shows that the photocurable composition (C2) and the illuminance of the light irradiating the coating layer (4 mW / cm²) are... 2 When compared with the same Example 2 and Comparative Example 2, the adhesive sheet of Example 2, which was prepared by irradiating light with an LED at a peak wavelength of 325 nm to 350 nm, had a lower residual amount of photopolymerization initiator compared to Comparative Example 2. Similarly, the adhesive sheets of Examples 1 and 3 to 13 also had a lower residual amount of photopolymerization initiator. Furthermore, in the adhesive sheets of Examples 1 to 13, the polymerization rate of the monomer group was sufficiently high. Therefore, it can be considered that the manufacturing method of this embodiment is suitable for efficiently producing adhesive sheets.

[0229] (Examples 14-16 and Comparative Examples 4-6)

[0230] The photocurable composition, light source, and light irradiation conditions used were modified as shown in Table 5. Otherwise, adhesive sheets of Examples 14-16 and Comparative Examples 4-6, held between a substrate sheet and a release liner L1, were obtained using the same method as in Example 1. It should be noted that in Comparative Examples 4-6, LEDs irradiating light with a peak wavelength of 365 nm were used as the light source.

[0231] [Residual amount of photopolymerization initiator, polymerization rate of monomer group]

[0232] For the adhesive sheets prepared in Examples 14-16 and Comparative Examples 4-6, the residual amount of photopolymerization initiator and the polymerization rate of the monomer group were calculated by the above method.

[0233] [Number-average molecular weight (Mn) and weight-average molecular weight (Mw) of the polymer]

[0234] Samples were prepared having the same composition as the photocurable compositions used in Examples 14-16 and Comparative Examples 4-6, except that they did not contain a crosslinking agent. The number-average molecular weight (Mn) and weight-average molecular weight (Mw) of the polymers were determined by the method described above.

[0235]

[0236] Table 5 shows that the photocurable composition (C11) and the illuminance of the light irradiating the coating layer (14 mW / cm²) are... 2 When compared with the same Example 16 and Comparative Example 6, the adhesive sheet of Example 16, which was prepared by irradiating light with an LED at a peak wavelength of 325 nm to 350 nm, showed a lower residual amount of photopolymerization initiator and a higher polymerization rate of monomer groups compared to Comparative Example 6. Similarly, the adhesive sheets of Examples 14 and 15 also showed a lower residual amount of photopolymerization initiator and a higher polymerization rate of monomer groups. Therefore, it can be considered that the manufacturing method of this embodiment is suitable for effectively producing adhesive sheets.

[0237] Industrial applicability

[0238] The adhesive sheet manufactured by the manufacturing method of the present invention can be used, for example, in optical laminates and image display devices.

Claims

1. A method for manufacturing an adhesive sheet, comprising: The process of forming an adhesive sheet by irradiating a coating layer containing a photocurable composition with light from a light-emitting diode. The peak wavelength of the light irradiating the coating layer is 325nm~350nm.

2. The manufacturing method according to claim 1, wherein, The peak wavelength is 340±10nm.

3. The manufacturing method according to claim 1, wherein, The illuminance of the light irradiating the coating layer is 2.0~30mW / cm². 2 .

4. The manufacturing method according to claim 1, wherein, The light is irradiated onto the laminate comprising the substrate sheet, the coating layer, and the release liner in sequence.

5. The manufacturing method according to claim 1, wherein, The coating layer is irradiated with light for 10 to 1000 seconds.

6. The manufacturing method according to claim 1, wherein, During the period when the coating layer is irradiated with light, the temperature of the coating layer is maintained at 10°C to 30°C.

7. The manufacturing method according to claim 1, wherein, The coating layer is irradiated with light in a gaseous atmosphere with an oxygen concentration of less than 500 volppm.

8. The manufacturing method according to claim 1, wherein, The photocurable composition comprises a monomer group and / or a portion of the polymer of the monomer group, wherein the monomer group comprises (meth)acrylic monomers.

9. The manufacturing method according to claim 8, wherein, In the adhesive sheet, the polymerization rate of the monomer group is above 80%.

10. The manufacturing method according to claim 8, wherein, The photocurable composition contains a photopolymerization initiator. The amount of the photopolymerization initiator is less than 1.0 part by weight relative to the total of 100 parts by weight of the monomer group and the partial polymer.

11. The manufacturing method according to claim 10, wherein, The content of the photopolymerization initiator in the adhesive sheet is less than 500 wtppm.

12. The manufacturing method according to claim 1, wherein, The solvent content in the photocurable composition is less than 5% by weight.

13. A method for manufacturing an optical film with an adhesive sheet, comprising: An optical film with an adhesive sheet is formed by placing an optical film on the exposed surface of the adhesive sheet formed by the manufacturing method according to any one of claims 1 to 12.

14. The manufacturing method according to claim 13, wherein, The optical film includes at least one film selected from polarizing films and phase difference films.

15. A method for manufacturing an image display device, comprising: An image display device is formed by bonding an optical film with an adhesive sheet, which is formed by the manufacturing method of claim 13, to an image display panel.

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