JP6538252B1 - Method of manufacturing image display device - Google Patents

Abstract

An object of the present invention is to provide a method of manufacturing an image display device having good adhesion performance at the time of temporary curing.
A method of manufacturing an image display device according to the present technology includes a step A of forming a curable resin layer 2 made of a photocurable resin composition on the surface of a front plate 4 or an image display member 1; Process B of irradiating the light from the UV-LED to the resin layer 2 to form the temporarily cured layer 5, process C of bonding the front plate 4 and the image display member 1 through the temporarily cured layer 5, and temporarily cured layer And 5) light irradiation through the front plate 4 to form a cured resin layer 6; The light to be irradiated in step B includes a first light having a peak in a wavelength range of 360 to 430 nm and a second light having a peak in a wavelength range of 200 to 345 nm. In the step B, the first light is irradiated to the curable resin layer 2 to irradiate the second light to the portion of the curable resin layer 2 where oxygen inhibition occurs.
[Selected figure] Figure 2

Description

  The present technology relates to a method of manufacturing an image display device.

  Patent Document 1 discloses a first irradiation step (temporary curing step) of irradiating light to an adhesive applied to at least one of the display panel and the substrate, and bonding of the display panel and the substrate after the first irradiation step. A method of manufacturing a display device is described which includes a bonding step and a second irradiation step (main curing step) of further irradiating light to an adhesive after the bonding step.

  The cured state of the outermost surface of the resin in the temporary curing step is very important in maintaining the alignment at the time of bonding. In the cured state of the outermost surface of the resin, the curing rate tends to be lower as the influence of oxygen inhibition at the time of temporary curing is larger, and the adhesion function also tends to be lowered accordingly. Therefore, as the ultraviolet irradiation device, one having a wide range of wavelengths and high output, such as a metal halide lamp or a high pressure mercury lamp, is preferable.

  However, in recent years, due to the demand for long life performance of the ultraviolet irradiation device, for example, a UV-LED having a peak in the wavelength range of 360 to 430 nm tends to be widely adopted as a light source. Since such UV-LEDs are used at a single wavelength, there is a concern about the decrease in adhesion performance at the time of temporary curing due to the effect of oxygen inhibition.

International Publication WO2009 / 054168

  The present technology has been proposed in view of such conventional circumstances, and provides a method of manufacturing an image display device having good adhesion performance at the time of temporary curing.

  In the method of manufacturing an image display device according to the present technology, a step A of forming a curable resin layer made of a photocurable resin composition on the surface of a front plate or an image display member, and a UV-LED curable resin layer The light is irradiated from the above to form a temporary curing layer B, the front plate and the image display member are bonded together via the temporary curing layer C, and the temporary curing layer is irradiated with light via the front plate And the step D of forming a cured resin layer, and the light irradiated in the step B has a first light having a peak in a wavelength range of 360 to 430 nm and a second light having a peak in a wavelength range of 200 to 345 nm. In the step B, the curable resin layer is irradiated with the first light, and the second light is irradiated to the site of the curable resin layer in which oxygen inhibition occurs.

  According to the present technology, the adhesion performance at the time of temporary curing can be improved.

FIG. 1 is a cross-sectional view for explaining an example of the step of forming a curable resin layer made of a photocurable resin composition on the surface of an image display member. FIG. 2: is sectional drawing for demonstrating an example of the process of irradiating a light from UV-LED to a curable resin layer, and forming a temporary hardening layer. FIG. 3: is sectional drawing for demonstrating an example of the process of irradiating a light from UV-LED to a curable resin layer, and forming a temporary hardening layer. FIG. 4: is sectional drawing for demonstrating an example of the process of bonding a front plate and an image display member together through a temporary hardening layer. FIG. 5: is sectional drawing for demonstrating an example of the process of light-irradiating with respect to a temporarily cured layer through a front plate, and forming a cured resin layer. FIG. 6 is a cross-sectional view showing an example of the image display device. FIGS. 7A to 7H are diagrams for explaining the preparation procedure of the test sample. FIG. 8 is a perspective view for explaining a method of measuring the shear strength of the temporarily cured layer. FIG. 9 is a graph showing the measurement results of the shear strength of the temporarily cured layer in the test samples obtained in Examples 1 to 6 and Comparative Examples 1 and 2. FIG. 10 is a graph showing the measurement results of the shear strength of the temporarily cured layer in the test samples obtained in Example 7 and Comparative Examples 3 to 5. FIG. 11 is a graph showing the measurement results of the shear strength of the temporarily cured layer in the test samples obtained in Example 8 and Comparative Examples 6 to 8. FIG. 12 is a graph showing the measurement results of the shear strength of the temporarily cured layer in the test samples obtained in Example 9 and Comparative Examples 9 to 11. FIG. 13 is a graph showing the measurement results of the shear strength of the temporarily cured layer in the test samples obtained in Example 10 and Comparative Example 12. FIG. 14 is a graph showing the measurement results of the shear strength of the cured resin layer obtained by fully curing the temporarily cured layer in the test sample obtained in Example 9.

  Hereinafter, details of a method of manufacturing an image display device according to the present technology (hereinafter, also referred to as the present manufacturing method) will be described. In the following description, (meth) acrylate includes both acrylate and methacrylate. Moreover, a (meth) acryloyl group includes both an acryloyl group and a methacryloyl group.

  In this manufacturing method, a step A of forming a curable resin layer made of a photocurable resin composition on the surface of a front plate or an image display member, and irradiating the curable resin layer with light from a UV-LED A step B of forming a cured layer, a step C of bonding the front plate and the image display member through the temporary curing layer, and light irradiation of the temporary curing layer through the front plate to form a cured resin layer And step D. The light to be irradiated in step B includes a first light having a peak in a wavelength range of 360 to 430 nm and a second light having a peak in a wavelength range of 200 to 345 nm. In the step B, the first light is irradiated to the curable resin layer, and the second light is irradiated to the portion of the curable resin layer in which oxygen inhibition occurs. The first light having a peak in the wavelength range of 360 to 430 nm has a smaller energy than the second light having a peak in the wavelength range of 200 to 345 nm, and reaches the deep portion of the curable resin layer. On the other hand, the second light having a peak in the wavelength range of 200 to 345 nm has a larger energy than the first light having a peak in the wavelength range of 360 to 430 nm, and does not reach the deep part of the curable resin layer. Reaches only the surface layer of the resin layer. By using in combination the first light having a peak in the wavelength range of 360 to 430 nm and the second light having a peak in the wavelength range of 200 to 345 nm as the light to be irradiated in step B, the wavelength range of 360 to 430 nm As compared with the case where only the first light having a peak is irradiated, the influence of oxygen inhibition can be reduced, and the adhesion performance at the time of temporary curing can be improved.

<Step A>
In step A of the present manufacturing method, as shown in FIG. 1, a curable resin layer 2 made of a photocurable resin composition is formed on the surface of the image display member 1. For example, in step A, the curable resin layer 2 is preferably formed on the entire surface of the image display member 1 by applying the photocurable resin composition so as to be flat. The thickness of the curable resin layer 2 is preferably set such that, for example, the step formed by the light shielding layer 3 described later and the surface on the light shielding layer formation side of the front plate 4 is cancelled. The thickness may be 2.5 to 40 times, 2.5 to 12.5 times, or 2.5 to 4 times. As an example, the thickness of the curable resin layer 2 may be 25 to 350 μm, and may be 50 to 150 μm. The number of times of application of the photocurable resin composition is not particularly limited as long as the required resin thickness can be obtained, and may be once or plural times.

  The image display member 1 is, for example, an image display panel in which a polarizing plate is formed on the surface on the viewing side of the image display cell. Examples of the image display cell include a liquid crystal cell and an organic EL cell. As a liquid crystal cell, a reflection type liquid crystal cell, a transmission type liquid crystal cell etc. are mentioned, for example. The image display member 1 is, for example, a liquid crystal display panel, an organic EL display panel, a touch panel or the like. The touch panel means an image display / input panel in which a display element such as a liquid crystal display panel and a position input device such as a touch pad are combined.

  The photocurable resin composition for forming the curable resin layer 2 contains, for example, a photoradical reactive component, at least one of a plasticizer and a tackifier component, and a photopolymerization initiator. The photocurable resin composition may further contain other components as long as the effects of the present technology are not impaired.

<Photo radical reactive component>
The photo radically reactive component contains at least one of (meth) acrylate oligomer and (meth) acrylate monomer. As the (meth) acrylate oligomer, one having a polyisoprene, a polyurethane, a polybutadiene or the like as a skeleton and having a polyurethane as a skeleton (urethane (meth) acrylate oligomer) is preferable. The (meth) acrylate oligomer preferably has 1 to 4 (meth) acrylic groups, and more preferably 2 to 3 (meth) acrylic groups. As a commercial item of a urethane (meth) acrylate oligomer, CN9014 (made by Sartmar company), EBECRYL 230, EBECRYL 270 (above, Daicel Ornex company make) etc. can be used, for example.

  The (meth) acrylate monomer is used as a reactive diluent for providing the photocurable resin composition with sufficient reactivity, coatability and the like. The (meth) acrylate monomer may be a monofunctional (meth) acrylate, a bifunctional (meth) acrylate, or a polyfunctional (meth) acrylate. The (meth) acrylate monomer is, for example, a (meth) acrylate monomer having a hydroxyl group (for example, 4-hydroxybutyl acrylate) or a (meth) acrylate monomer having a cyclic structure (for example, iso) from the viewpoint of compatibility with other components. Bornyl acrylate, dicyclopentenyl oxyethyl methacrylate), alkyl (meth) acrylate monomer having 5 to 20 carbon atoms (eg, n-octyl acrylate, isodecyl acrylate, lauryl acrylate, isostearyl acrylate), polyfunctional (meth) acrylate It is preferable to contain a monomer (for example, pentaerythritol (tri / tetra) acrylate, neopentyl glycol diacrylate hydroxypivalate) and the like.

  The total of the content of the (meth) acrylate oligomer and the (meth) acrylate monomer in the photocurable resin composition can be 95% by mass or less, and may be 90% by mass or less. Moreover, the sum total of the content of the (meth) acrylate oligomer and the (meth) acrylate monomer in the photocurable resin composition can be 20 mass% or more, and may be 30 mass% or more, 35 mass It may be% or more. The (meth) acrylate oligomer and / or the (meth) acrylate monomer may be used alone or in combination of two or more. When two or more (meth) acrylate oligomers and / or (meth) acrylate monomers are used in combination, the total content is preferably within the above-mentioned range.

<Photoinitiator>
As the photopolymerization initiator, known photo radical polymerization initiators can be used. As the photopolymerization initiator, an alkylphenone photopolymerization initiator, an acyl phosphine oxide photopolymerization initiator, a benzophenone photopolymerization initiator, an intramolecular hydrogen abstraction type photopolymerization initiator, and the like can be used. Specific examples thereof include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 1-hydroxy-cyclohexyl-phenyl-ketone, methyl phenylglyoxylate and the like. Examples of commercially available products include LUCIRIN TPO, Irgacure 184, IRGACURE MBF (above, manufactured by BASF Corporation), Esacure TZT (manufactured by Lamberti), and the like.

  The total content of the photopolymerization initiator in the photocurable resin composition can be 10% by mass or less, may be 8% by mass or less, and may be 6% by mass or less. In addition, the total content of the photopolymerization initiator in the photocurable resin composition can be 0.1% by mass or more, and may be 1% by mass or more, and 2% by mass or more It is also good. A photoinitiator may be used individually by 1 type, and may use 2 or more types together. When using 2 or more types of photoinitiators together, it is preferable that the sum total of the content exists in the range mentioned above.

<Plasticizer and Tackifier>
The plasticizer and the tackifier are those which do not substantially react with (meth) acrylate oligomer and (meth) acrylate monomer by light irradiation. The tackifier component includes a solid tackifier and a liquid oil component. Examples of solid tackifiers include terpene resins such as terpene resins, terpene phenol resins, hydrogenated terpene resins, natural rosins, polymerized rosins, rosin esters, rosin resins such as hydrogenated rosins, and terpene hydrogenated resins. . Examples of the liquid oil component include polybutadiene type oils and polyisoprene type oils. As a commercial item of a plasticizer and a tackifier, Clearon M105 (made by Yashara Chemical Co., Ltd.), GI-1000, GI-3000 (made by Nippon Soda Co., Ltd.) etc. are mentioned, for example.

  When the photocurable resin composition contains at least one of a plasticizer and a tackifier, the total content of the plasticizer and the tackifier in the photocurable resin composition is 70% by mass or less. And may be 65% by mass or less, 60% by mass or less, or 58% by mass or less. Further, the total content of the plasticizer and tackifier in the photocurable resin composition can be 0.5 mass% or more, may be 2 mass% or more, and 4 mass% or more. There may be, 5 mass% or more may be sufficient, and 7 mass% or more may be sufficient. The plasticizer and / or the tackifier may be used alone or in combination of two or more. When two or more plasticizers and / or tackifiers are used in combination, the total content of the plasticizer and / or tackifier is preferably in the range described above.

<Other ingredients>
The photocurable resin composition is, for example, a polymer component (a polymer component other than the above-described photoradically reactive component, plasticizer, and tackifier) other than the above-described components within the range not impairing the effects of the present technology. It may further contain an inhibitor, a light stabilizer, a silane coupling agent and the like. As the polymer component, for example, Hytaloid 7927 (manufactured by Hitachi Chemical Co., Ltd.) can be used. The Hytalloy 7927 is an ultraviolet curable resin containing a polymer as a main component and an acrylic monomer as a reactive diluent, but the polymer as a main component functions as a tackifier. In the present invention, in the case where the photocurable resin composition includes the vitaroid 7927, the content of the vitaroid 7927 in the photocurable resin composition is calculated as the content of the tackifier described above. As the antioxidant, for example, a hindered phenol-based antioxidant can be used. As a commercial item of antioxidant, IRGANOX1520L and IRGANOX1010 (above, BASF Corporation make) can be used, for example. As the light stabilizer, for example, a hindered amine light stabilizer can be used. As a commercial item of a light stabilizer, Adekastab LA-52 (made by ADEKA) can be used, for example. As silane coupling, for example, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-mercaptopropyltrimethoxysilane can be used. As a commercial item of silane coupling, KBM5103, KBM503, KBM803 (above, Shin-Etsu Silicone Co., Ltd. make) can be used, for example.

<Step B>
In the process B of this manufacturing method, as shown in FIG. 2, light is irradiated to the curable resin layer 2 from UV-LED, and the temporarily cured layer 5 as shown in FIG. 3 is formed. In step B, with respect to the curable resin layer 2 formed in step A, a first light having a peak in a wavelength range of 360 to 430 nm and a second light having a peak in a wavelength range of 200 to 345 nm Irradiate.

The light irradiation in step B is preferably performed so that the reaction rate of the temporary curing layer 5 is 10 to 90%, more preferably 40 to 90%, and 70 to 90%. More preferably, The reaction rate is a numerical value defined as a ratio (consumption amount ratio) of a (meth) acryloyl group presence after light irradiation to a (meth) acryloyl group presence in a curable resin layer before light irradiation. . The larger the value of the reaction rate, the more the curing progresses. Specifically, the reaction rate is the absorption peak height (X) of 1640 to 1620 cm ⁻¹ from the baseline in the FT-IR measurement chart of the curable resin layer before light irradiation, and the curable resin after light irradiation The absorption peak height (Y) of 1640 to 1620 cm ⁻¹ from the baseline in the FT-IR measurement chart of the layer (cured resin layer 6) can be calculated by substituting the following expression.
Reaction rate (%) = [(X-Y) / X] x 100

  In step B, the first light having a peak in the wavelength range of 360 to 430 nm is applied to the curable resin layer 2 to cause oxygen inhibition at the site of the curable resin layer 2, specifically, the curable resin layer 2 It is preferable to irradiate the surface with a first light having a peak in a wavelength range of 360 to 430 nm and a second light having a peak in a wavelength range of 200 to 345 nm.

In step B, the light is irradiated such that the integrated light quantity of the first light having a peak in the wavelength range of 360 to 430 nm is larger than the integrated light quantity of the second light having a peak in the wavelength range of 200 to 345 nm. Is preferred. Thereby, the adhesion performance at the time of temporary curing can be made better. As an example, the integrated light amount of the first light having a peak in the wavelength range of 360 to 430 nm is in the range of 2000 to 5000 mJ / cm ² and the integrated light amount of the second light having a peak in the wavelength range of 200 to 345 nm It is preferable that it is a range of 20 mJ / cm ² or more and less than 1000 mJ / cm ² . In the step B, as the first light having a peak in the wavelength range of 360 to 430 nm, for example, light having an emission wavelength of 365 ± 5 nm is preferably irradiated under the condition of an illuminance of 100 to 500 mW / cm ² . Moreover, in the step B, it is preferable to irradiate, for example, light having a light emission wavelength of 280 ± 5 nm under the condition of an illuminance of 10 to 100 mW / cm ² as the second light having a peak in the wavelength range of 200 to 345 nm. As the UV-LED used in step B, for example, an LED having an emission peak wavelength in the range of 360 to 430 nm (example: emission wavelength of 365 ± 5 nm) and an emission wavelength peak wavelength of 200 to 345 nm (example: emission wavelength A device having an LED that is 280 ± 5 nm) can be used.

  In the step B, the first light having a peak in the wavelength range of 360 to 430 nm may be simultaneously irradiated with the second light having a peak in the wavelength range of 200 to 345 nm. Moreover, in the process B, after irradiating 1st light which has a peak in the range of wavelength 360-430 nm, you may irradiate 2nd light which has a peak in the range of 200-345 nm wavelength. Moreover, in the process B, after irradiating the 2nd light which has a peak in the range of wavelength 200-345 nm, you may irradiate the 1st light which has a peak in the range of wavelength 360-430 nm.

  In the present manufacturing method, it is preferable to prevent dripping or deformation of the temporarily cured layer 5 during the laminating operation in step C described later. For example, in step B, before the curable resin layer 2 is irradiated with the first light having a peak in the wavelength range of 360 to 430 nm and the second light having a peak in the wavelength range of 200 to 345 nm, It is preferable to perform light irradiation so that the viscosity of the resin layer 2 is 20 Pa · S or more (a cone plate rheometer, 25 ° C., a cone and a plate C 35/2, rotation speed 10 rpm).

<Step C>
In the step C, for example, as shown in FIG. 4, the front plate 4 and the image display member 1 are bonded to each other through the temporary curing layer 5. For example, in the step C, the front plate 4 is attached to the image display member 1 from the side of the temporary curing layer 5. Bonding can be performed by pressurizing at 10-80 degreeC, for example using a well-known crimping | compression-bonding apparatus.

  The front plate 4 may have any light transmittance such that the image formed on the image display member 2 can be visually recognized. For example, a plate of glass, acrylic resin, polyethylene terephthalate, polyethylene naphthalate, polycarbonate or the like Materials and sheet materials. These materials may be subjected to hard coating treatment, anti-reflection treatment, etc. on one side or both sides. Physical properties such as thickness and elastic modulus of the front plate 4 can be appropriately determined according to the purpose of use. The front plate 4 may be a stack of various sheets or film materials such as a touch panel module.

  A light shielding layer 3 may be provided on the periphery of the front plate 4 in order to improve the contrast of the image. The light shielding layer 3 can be formed, for example, by applying a paint colored in black or the like by a screen printing method or the like, and drying and curing it. The thickness of the light shielding layer 3 is usually 5 to 100 μm.

<Step D>
In Step D, for example, light is irradiated to the temporary curing layer 5 shown in FIG. 5 through the front plate 4 to form a cured resin layer 6 as shown in FIG. The main curing of the temporary curing layer 5 in step D is to sufficiently cure the temporary curing layer 5 to bond and laminate the image display member 1 and the front plate 4. By performing the step D, as shown in FIG. 6, an image display device 7 provided with the image display member 1, the cured resin layer 6, and the front plate 4 in this order is obtained.

The main curing (light irradiation) in the step D is preferably performed so that the reaction rate of the cured resin layer 6 is 90% or more, and more preferably 97% or more. There are no particular restrictions on the type of light source, output, illuminance, integrated light amount, etc. when performing main curing, and photo radical polymerization process conditions of (meth) acrylate by known ultraviolet irradiation can be adopted. For example, ultraviolet irradiation, ultraviolet ray irradiation device (a metal halide lamp, high pressure mercury lamp, UV-LED, etc.) using, it is preferable to carry out at an intensity 50~300mW / cm ^2, the integrated quantity of light 1000~6000mJ / cm ² conditions. In particular, in the step D, it is preferable to irradiate the first light having a peak in the wavelength range of 360 to 430 nm using a UV-LED from the requirement of the long life performance of the ultraviolet irradiation device as described above.

  In Step D, if necessary, the temporary curing layer 5 may be fully cured by irradiating the temporary curing layer 5 between the light shielding layer 3 of the front plate 4 and the image display member 1 with light. .

  The cured resin layer 6 in the image display 7 obtained by the present manufacturing method preferably has a transmittance of 90% or more in the visible light region. By satisfying such a range, the visibility of the image formed on the image display member 1 can be further improved. The refractive index of the cured resin layer 6 is preferably substantially equal to the refractive index of the image display member 1 and the front plate 4. The refractive index of the cured resin layer 6 is preferably, for example, 1.45 or more and 1.55 or less. Thereby, the brightness | luminance and contrast of the imaging light from the image display member 1 can be improved, and visibility can be improved. The thickness of the cured resin layer 6 can be, for example, about 25 to 200 μm.

  According to the present manufacturing method as described above, the adhesion performance at the time of temporary curing can be improved.

  In the process A, instead of applying the photocurable resin composition to the surface of the image display member 1, the photocurable resin composition is applied to the surface of the front plate 4 on which the light shielding layer 3 is formed. You may Moreover, you may use the front plate which does not have the light shielding layer 3 as a front plate.

  Hereinafter, examples of the present technology will be described. The present technology is not limited to these examples.

<Preparation of Photocurable Resin Composition>
Each component was uniformly mixed by the compounding quantity (mass part) shown in Table 1, and the photocurable resin composition was prepared.

Abbreviations in Table 1 are the following compounds.
Urethane acrylate oligomer: Number average molecular weight 20000
CN9014: Urethane acrylate oligomer, Sartomer's Hitachiloid 7927: Hitachi Chemical 4HBA: 4-hydroxybutyl acrylate, BASF ISTA: isostearyl acrylate, Osaka Organic Chemicals Miramer M210: hydroxypivalate neopentyl glycol diacrylate, MIWON PETIA: pentaerythritol (tri / tetra) acrylate NOA: n-octyl acrylate IDA: isodecyl acrylate IBXA: isobornyl acrylate FA-512M: dicyclopentenyloxyethyl methacrylate LA: lauryl acrylate M105: terpene resin, product Name: Clearon M105, manufactured by Yashara Chemical Co., Ltd. GI-1000: Both terminal hydroxylated polybutadiene, Japan Soda Co., Ltd. GI-3000: Both end hydroxyl group hydrogenated polybutadiene, Nippon Soda Co., Ltd. terpene resin: Number average molecular weight 800
TPO: 2,4, 6-trimethylbenzoyl-diphenyl-phosphine oxide, product name: LUCIRIN TPO, manufactured by BASF Irg 184 D: 1-hydroxy-cyclohexyl-phenyl-ketone, product name; Irgacure 184, manufactured by BASF MBF: phenylglyoxyl Acid methyl, product name; IRGACURE MBF, BASF TZT: Product name; Esacure TZT, Lamberti

Example 1
<Preparation of Test Sample Using Resin A>
As shown in FIG. 7A, the photocurable resin composition 12 was applied to a thickness of 33 μm from the slit nozzle 11 from one end side to the other end side of the surface of the PET film 10 (thickness 130 mm) Thereafter, the applied photo-curable resin composition 12 was irradiated with light having a peak at a wavelength of 365 nm from the UV-LED 13 so that the integrated light amount would be 500 mJ / cm ² . This light irradiation is performed in order to suppress dripping of the applied photocurable resin composition. Thus, a first curable resin layer 14A was formed. Next, as shown in FIG. 7B, the photocurable resin composition 12 is applied from the slit nozzle 11 to a thickness of 33 μm on the curable resin layer 14A, and then the applied photocurable resin composition The second curable resin layer 14B was formed by irradiating the object 12 with light having a peak at a wavelength of 365 nm so that the integrated light amount is 500 mJ / cm ² from the UV-LED 13. This light irradiation is also performed in order to suppress dripping of the applied photocurable resin composition. Next, as shown in FIG. 7C, the photocurable resin composition 12 is applied from the slit nozzle 11 to a thickness of 33 μm on the curable resin layer 14B, and then the applied photocurable resin composition The third curable resin layer 14C was formed by irradiating the object 12 with light having a peak at a wavelength of 365 nm so that the integrated light amount is 500 mJ / cm ² from the UV-LED 13. This light irradiation is also performed in order to suppress dripping of the applied photocurable resin composition. Thus, a laminate in which a curable resin layer 14 having a thickness of about 100 μm was formed on the PET film 10 was obtained.

As shown in FIG. 7D, UV-LEDs (a plurality of LEDs having an emission wavelength of 365 nm, manufactured by CCS, and a plurality of LEDs having an emission wavelength of 280 nm, are used for the curable resin layer 14 of the laminate. device with bets from irradiation range 80 mm × 80 mm), and a light having a peak wavelength 365nm of 200 mW / cm ² intensity as integrated light quantity is 5000 mJ / cm ^2, so that the integrated light quantity is 20 mJ / cm ² The light which has a peak in wavelength 280nm of 20 mW / cm < ² > intensity | strength was irradiated. Thereby, the laminated body by which the temporarily cured layer 15 was formed on PET film 10 was obtained. It was about 80 to 90% when the hardening rate of the temporary hardening layer 15 was calculated | required using the absorption peak height of 1640 to 1620 cm < ^-1 > from the baseline in a FT-IR measurement chart as a parameter | index.

  As shown in FIG. 7E, the laminate was cut to a width of 25 mm. As shown to FIG. 7 (F), the cut laminated body was affixed on the slide glass 16 (width 25 mm, thickness 1 mm). As shown in FIG. 7 (G), pressure was applied using a 2 kg load roller 17 from the laminate side. Thus, the test sample 18 shown in FIG. 7H, that is, the test sample in which the PET film 10 and the slide glass 16 are bonded to each other via the temporary curing layer 15 (10 mm × 25 mm, thickness 0.1 mm). I got eighteen.

<Shear strength measurement of temporary hardened layer>
The shear strength of the temporarily cured layer 15 in the test sample 18 was measured by the method shown in FIG. Specifically, using a table-type precision universal testing machine (Autograph, manufactured by Shimadzu Corporation), the PET film 10 located on the lower side of the test sample 18 is fixed with a jig 19 and a slide glass located on the upper side The shear strength of the temporary curing layer 15 was measured when 16 was peeled off at a speed of 5 mm / min in the vertical direction via the jig 20. The results are shown in FIG. 9 and Table 2.

[Examples 2 to 6, Comparative Examples 1 and 2]
A test sample was prepared in the same manner as in Example 1 except that the integrated light quantity of light irradiated to the curable resin layer 14 of the laminate was as shown in the following table, and a temporary cured layer in the test sample Shear strength was measured. The results are shown in FIG. 9 and Table 2.

[Example 7, Comparative Examples 3 to 5]
A test sample is prepared and tested in the same manner as in Example 1 except that the accumulated light quantity of the light irradiated to the curable resin layer 14 of the laminate is made as shown in the table below using the resin B. The shear strength of the temporarily cured layer in the sample for use was measured. The results are shown in FIG. 10 and Table 3.

[Example 8, Comparative Examples 6 to 8]
A sample for test was prepared and tested in the same manner as in Example 1 except that the accumulated light quantity of the light irradiated to the curable resin layer 14 of the laminate was made as shown in the following table using Resin C. The shear strength of the temporarily cured layer in the sample for use was measured. The results are shown in FIG. 11 and Table 4.

[Example 9, Comparative Examples 9 to 11]
A test sample was prepared and tested in the same manner as in Example 1 except that the accumulated light quantity of the light irradiated to the curable resin layer 14 of the laminate was made as shown in the following table using Resin D. The shear strength of the temporarily cured layer in the sample for use was measured. In Comparative Example 10, the UV-LED, integrated light quantity is irradiated with only light having a peak wavelength 365nm of 600 mW / cm ² intensity so that the 6000 mJ / cm ^2. The results are shown in FIG. 12 and Table 5.

[Example 10, Comparative Example 12]
A sample for test was prepared and tested in the same manner as in Example 1 except that the accumulated light quantity of the light irradiated to the curable resin layer 14 of the laminate was made as shown in the following table using Resin E. The shear strength of the temporarily cured layer in the sample for use was measured. The results are shown in FIG. 13 and Table 6.

  From the results of Examples 1 to 10 and Comparative Examples 1 to 12, the light irradiated in the step of forming the temporary cured layer by irradiating the curable resin layer with light from the UV-LED has a peak in the wavelength range of 360 to 430 nm. The shear strength of the temporary curing layer is good, that is, the adhesion performance at the time of temporary curing is good, by including the first light having the second light and the second light having the peak in the wavelength range of 200 to 345 nm. It turned out that there is. Further, from the results of Example 9 and Comparative Example 11, it was found that in Example 9, the adhesion performance at the time of temporary curing equal to or higher than that at the metal halide lamp irradiation can be realized. Furthermore, it turned out that the tendency of the improvement of the adhesive performance at the time of temporary hardening does not depend on the composition ratio of a photocurable resin composition from the result of Examples 1-10.

From the results of Examples 1 to 6, in the case of using the resin A, in the step of irradiating the curable resin layer with light from the UV-LED to form a temporary cured layer, the peak is in the wavelength range of 360 to 430 nm. first integrated quantity of light of the light is in a range of 2000~5000mJ / cm ^2, the second range integrated light quantity is less than 20 mJ / cm ² or more 1000 mJ / cm ² of light having a peak in a wavelength range of 200~345nm having It has been found that it is preferable that the integrated light amount of the second light having a peak in the range of wavelength 200 to 345 nm is in the range of 500 mJ / cm ² or more and less than 1000 mJ / cm ² .

  In Example 8 and Comparative Examples 6 to 8, since resin C containing a photopolymerization initiator exhibiting relatively mild reactivity and containing a large proportion of plasticizer was used, compared to the case where other resins were used. Although the shear strength at the time of temporary hardening tended to be difficult to develop, it was found that Example 8 exhibited a shear strength twice or more that in Comparative Examples 6 to 8.

  In Comparative Examples 1 to 12, the light irradiated in the step of forming the temporary cured layer by irradiating the curable resin layer with light from the UV-LED is only light having a peak in the wavelength range of 360 to 430 nm, or Since only the light which has a peak in the range of 200-345 nm is included, it turned out that the adhesion performance at the time of temporary hardening is not good.

In Comparative Example 4, although the integrated light quantity of light having a peak in the range of wavelength 360 to 430 nm from the UV-LED was increased to 8000 mJ / cm ² , no light having a peak in the range of wavelength 200 to 345 nm was irradiated. The shear strength was found to be extremely low compared to Example 7. Moreover, in Comparative Example 5 in which only light having a peak in a wavelength range of 200 to 345 nm was irradiated, it was found that the shear strength was extremely low as compared with Example 7. From these results, in consideration of the curability of the deep part of the curable resin layer, in the step of forming the temporary curing layer, light having a peak in the wavelength range of 360 to 430 nm and a peak in the wavelength range of 200 to 345 nm It turned out that it is essential to use light together.

In Comparative Example 10, the illuminance of light having a peak in the wavelength range of 360 to 430 nm from the UV-LED is increased to 600 mW / cm ² and the integrated light amount is increased to 6000 mJ / cm ² , but the wavelength is 200 to 345 nm Since it did not irradiate with the light which has a peak in the range of, it turned out that the measurement result of shear strength is inferior to Example 9.

<Shear strength measurement of cured resin layer>
[Example 9-1]
The temporarily cured layer of the test sample in Example 9 was irradiated with light having an intensity of 200 mW / cm ² so that the integrated light amount was 5000 mJ / cm ² , using a metal halide lamp with a conveyor (manufactured by USIO). Thereby, the temporarily cured layer was completely cured to form a cured resin layer. The curing rate of the cured resin layer was 97%. The shear strength of this cured resin layer was measured by the same method as the above-mentioned temporary cured layer. The results are shown in FIG. In addition, N1-N4 in FIG. 14 prepare four samples for each test, and represent the measurement result of the shear strength about four samples for a test. The average (*) in FIG. 14 represents the average value of the measurement results of shear strength of N1 to N4.

[Example 9-2]
The temporary curing layer of the test sample in Example 9 was surface-irradiated using a UV-LED with light having a peak at a wavelength of 365 nm of 200 mW / cm ² so that the integrated light amount would be 5000 mJ / cm ² . . Thereby, the temporarily cured layer was completely cured to form a cured resin layer. The curing rate of the cured resin layer was 97%. The shear strength of this cured resin layer was measured by the same method as the above-mentioned temporary cured layer. The results are shown in FIG.

Comparative Example 9-1
The shear strength of the cured resin layer was measured in the same manner as in Example 9-1 except that the test sample in Comparative Example 9 was used. The results are shown in FIG.

Comparative Example 9-2
The shear strength of the cured resin layer was measured in the same manner as in Example 9-2 except that the test sample in Comparative Example 9 was used. The results are shown in FIG.

  From the results of Examples 9-1 and 9-2 and Comparative Examples 9-1 and 9-2, it was found that the strengths of the cured resin layers were almost the same. This is considered to be because the difference in physical adhesion (effect of oxygen inhibition) appears significantly at the time of temporary curing, while the difference in chemical adhesion is also added after this curing.

REFERENCE SIGNS LIST 1 image display member, 2 curable resin layer, 3 light shielding layer, 4 front plate, 5 temporary cured layer, 6 cured resin layer, 7 image display device, 10 PET film, 11 slit nozzle, 12 photocurable resin composition, 13 UV-LED, 14 curing resin layer, 15 temporary curing layer, 16 slide glass, 17 load roller, 18 test sample, 19 jig, 20 jig

Claims (9)

Step A of forming a curable resin layer comprising a photocurable resin composition on the surface of a front plate or an image display member
A step B of irradiating the curable resin layer with light from a UV-LED to form a temporary cured layer;
A process C of bonding the front plate and the image display member through the temporary curing layer;
Irradiating the light through the front plate to the temporary curing layer to form a curing resin layer D;
The light to be irradiated in the step B includes a first light having a peak in a wavelength range of 360 to 430 nm and a second light having a peak in a wavelength range of 200 to 345 nm.
In the step B, the first light and the second light are simultaneously irradiated, and the first light is irradiated to the curable resin layer to cause oxygen inhibition at the site of the curable resin layer. The manufacturing method of an image display apparatus which irradiates 2 lights.   In the step B, the curable resin layer is irradiated with the first light and the second light so that the integrated light amount of the first light is larger than the integrated light amount of the second light. A method of manufacturing an image display device according to claim 1.   The method for manufacturing an image display device according to claim 1, wherein in the step B, the first light and the second light are irradiated to the surface of the curable resin layer.   The manufacturing method of the image display apparatus of any one of Claims 1-3 whose thickness of the said curable resin layer is 25-350 micrometers. In the step B, in the range integrated light quantity of the first light is 2000~5000mJ / cm ^2, in the range integrated light quantity is less than 20 mJ / cm ² or more 1000 mJ / cm ² of the second light, wherein The manufacturing method of the image display apparatus of any one of claim | item 1 -4.   The photocurable resin composition according to any one of claims 1 to 5, wherein the photocurable resin composition comprises a photoradical reactive component, a photopolymerization initiator, and at least one of a plasticizer and a tackifier component. Method of manufacturing an image display device   The method for manufacturing an image display device according to claim 6, wherein the light radical reactive component contains at least one of (meth) acrylate oligomer and (meth) acrylate monomer.   The photopolymerization initiator contains at least one of an alkylphenone photopolymerization initiator, an acyl phosphine oxide photopolymerization initiator, a benzophenone photopolymerization initiator, and an intramolecular hydrogen abstraction photopolymerization initiator. Item 8. A method of manufacturing an image display device according to item 6 or 7.   The photocurable resin composition comprises 30 to 90% by mass of the photoradically reactive component, 2 to 6% by mass of the photopolymerization initiator, and at least one of the plasticizer and the tackifier component. The manufacturing method of the image display apparatus of any one of Claims 6-8 containing 5-58 mass%.