KR20200033173A - Method for manufacturing image display device - Google Patents

Abstract

Provided is a method for manufacturing an image display device having a good adhesive performance in a temporary curing. The method for manufacturing an image display device related to the technology comprises: a process A of forming a curable resin layer (2) formed by a photocurable resin composition on a front plate (4) or a surface of an image display member (1); a process B of forming a temporary cured layer (5) by irradiating light from UV-LED to the curable resin layer (2); a process C of bonding the front plate (4) to the image display member (1) through the temporary cured layer (5); and a process D of irradiating light to the temporary cured layer (5) through the front plate (4) and forming a cured resin layer (6). The light irradiated in the process B includes a first light having a peak in a range of 360-430 nm of a wavelength, and a second light having a peak in a range of 200-345 nm of a wavelength. In a process B, the first light is irradiated to a curable resin layer (2) and then, the second light is irradiated to part of the curable resin layer (2) generating oxygen inhibition.

Description

Manufacturing method of an image display device {METHOD FOR MANUFACTURING IMAGE DISPLAY DEVICE}

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

In patent document 1, the 1st irradiation process (temporary hardening process) which irradiates the adhesive agent applied to at least one of a display panel and a board | substrate and the 1st irradiation process and a display panel and a board | substrate are stuck together. A manufacturing method of a display device including a bonding step and a second irradiation step (this curing step) of irradiating light to the adhesive after the bonding step is described.

The state of curing of the outermost surface of the resin in the temporary curing step is very important for maintaining alignment during bonding. The hardened state of the outermost surface of the resin tends to have a lowered curing rate, and the adhesive function tends to decrease as the effect of oxygen inhibition during temporary curing increases. Therefore, as the ultraviolet irradiation device, it is preferable that a wide range of wavelengths and high power, such as a metal halide lamp or a high pressure mercury lamp.

However, in recent years, from the request of high lifespan performance of the ultraviolet irradiation device, for example, UV-LEDs having peaks in the range of wavelengths of 360 to 430 nm tend to be employed as light sources. Since such UV-LEDs are used at a single wavelength, there is concern about a decrease in adhesion performance during temporary curing under the influence of oxygen inhibition.

International publication WO2009 / 054168

The present technology is proposed in view of such a conventional situation, and provides a method for manufacturing an image display device having good adhesion performance during temporary curing.

The manufacturing method of the image display apparatus which concerns on this technology is the process A which forms the curable resin layer which consists of a photocurable resin composition on the front plate or the surface of an image display member, and the curable resin layer is irradiated with light from UV-LED. A process B for forming a temporary cured layer, a process C for bonding the front plate and an image display member through the temporary cured layer, and a process D for irradiating the temporary cured layer through the front plate and forming a cured resin layer , And the light irradiated in step B includes a first light having a peak in the range of wavelengths of 360 to 430 nm and a second light having a peak in the range of wavelengths of 200 to 345 nm. 1 light is irradiated to the curable resin layer, and the second light is irradiated to the portion of the curable resin layer where oxygen inhibition occurs.

According to the present technology, adhesion performance during temporary curing can be improved.

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

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

This manufacturing method comprises the step A of forming a curable resin layer made of a photocurable resin composition on the front panel or the surface of an image display member, and forming a temporary cured layer by irradiating the curable resin layer with light from a UV-LED. It has a process B, a process C for bonding the front plate and the image display member through the temporary cured layer, and a process D for irradiating the temporary cured layer through the front plate and forming a cured resin layer. The light irradiated in step B includes a first light having a peak in the range of wavelengths of 360 to 430 nm and a second light having a peak in the range of wavelengths of 200 to 345 nm. In 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 where oxygen inhibition occurs. The first light having a peak in the wavelength range of 360 to 430 nm is smaller in energy than the second light having a peak in the range of wavelength of 200 to 345 nm, and reaches the core of the curable resin layer. On the other hand, the second light having a peak in the range of wavelengths of 200 to 345 nm has a greater energy compared to the first light having a peak in the range of wavelengths of 360 to 430 nm, and does not reach the core of the curable resin layer, and can be cured. It only touches the surface layer of the strata. As the light irradiated in the step B, by using the first light having a peak in the range of wavelengths of 360 to 430 nm and the second light having a peak in the range of wavelengths of 200 to 345 nm, the wavelength is in the range of 360 to 430 nm. Compared to the case where only the first light having a peak is irradiated, the effect of oxygen inhibition can be reduced, and the adhesion performance during temporary curing can be improved.

<Process A>

In step A of the production 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, it is preferable to form the curable resin layer 2 by coating the entire surface of the image display member 1 so that the photocurable resin composition becomes flat. The thickness of the curable resin layer 2 is preferably, for example, a thickness at which steps formed on the light-shielding layer forming side surfaces of the light-shielding layer 3 and the front plate 4 described later are canceled, and the light-shielding layer ( It can be made 2.5 to 40 times the thickness of 4), and may be 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 the photocurable resin composition is applied is not particularly limited as long as the required resin thickness is obtained, and may be performed once or multiple times.

The image display member 1 is, for example, an image display panel in which a polarizing plate is formed on the viewing side surface of an 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 reflective liquid crystal cell, a transmissive 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, or a touch panel. 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 kind of a plasticizer and a tackifier component, and a photopolymerization initiator. The photocurable resin composition may further contain other components within a range that does not impair the effects of the present technology.

<Photo-radical reactive component>

The photoradical reactive component contains at least one of (meth) acrylate oligomer and (meth) acrylate monomer. The (meth) acrylate oligomer is preferably one having polyisoprene, polyurethane, polybutadiene, etc. on the skeleton, and having polyurethane on the skeleton (urethane (meth) acrylate oligomer). The (meth) acrylate oligomer preferably has 1 to 4 (meth) acrylic groups, and more preferably has 2 to 3 (meth) acrylic groups. As a commercial item of a urethane (meth) acrylate oligomer, CN9014 (made by Sartomer), EBECRYL 230, EBECRYL 270 (above, manufactured by Daicel Allnex), etc. can be used.

The (meth) acrylate monomer is used as a reactive diluent for imparting sufficient reactivity and coatability to the photocurable resin composition. 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, from the viewpoint of compatibility with other components, (meth) acrylate monomer having a hydroxyl group (for example, 4-hydroxybutylacrylate), (meth) having a cyclic structure ) Acrylate monomers (e.g., isobornyl acrylate, dicyclopentenyloxyethyl methacrylate), alkyl (meth) acrylate monomers having 5 to 20 carbon atoms (e.g., n-octyl acrylate, iso Decyl acrylate, lauryl acrylate, isostearyl acrylate), polyfunctional (meth) acrylate monomers (e.g. pentaerythritol (tri / tetra) acrylate, hydroxypivalic acid neopentyl glycol diacrylate) ) And the like.

The sum 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 of the content of the (meth) acrylate oligomer and the (meth) acrylate monomer in a photocurable resin composition can be 20 mass% or more, and may be 30 mass% or more, and may be 35 mass% or more. (Meth) acrylate oligomer and / or (meth) acrylate monomer may be used individually by 1 type, and may use 2 or more types together. When using 2 or more types of (meth) acrylate oligomers and / or (meth) acrylate monomers together, it is preferable that the total of the content is in the above-mentioned range.

<Photopolymerization initiator>

As the photopolymerization initiator, a known photoradical polymerization initiator can be used. As the photopolymerization initiator, an alkylphenone-based photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator, a benzophenone-based photopolymerization initiator, an intramolecular hydrogen drawing type photopolymerization initiator, or the like can be used. Specific examples include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 1-hydroxy-cyclohexyl-phenyl-ketone, methyl phenylglyoxylate, and the like. Examples of commercial products include LUCIRIN TPO, Irgacure184, IRGACURE MBF (above, manufactured by BASF), Esacure TZT (made by Lamberti), and the like.

The total content of the photopolymerization initiator in the photocurable resin composition may be 10% by mass or less, or 8% by mass or less, or 6% by mass or less. Moreover, the sum of content of the photoinitiator in a photocurable resin composition can be 0.1 mass% or more, 1 mass% or more, or 2 mass% or more. The photopolymerization initiator may be used alone or in combination of two or more. When using 2 or more types of photoinitiators together, it is preferable that the total content is in the range mentioned above.

<Plasticizer and tackifier>

The plasticizer and the tackifier are those in which (meth) acrylate oligomer and (meth) acrylate monomer do not substantially react by light irradiation. Examples of the tackifying component include a solid tackifier and a liquid oil component. Examples of the solid tackifier include terpene resins such as terpene resins, terpene phenol resins, and hydrogenated terpene resins, natural rosin, polymerized rosin, rosin esters, rosin resins such as hydrogenated rosin, and terpene hydrogenated resins. . As a liquid oil component, polybutadiene oil, polyisoprene oil, etc. are mentioned. As a commercial item of a plasticizer and a tackifier, Clearlon M105 (made by Yasuhara Chemical), GI-1000, GI-3000 (made by Nippon Soda) etc. are mentioned, for example.

When the photocurable resin composition contains at least one kind of a plasticizer and a tackifier, the total content of the plasticizer and the tackifier in the photocurable resin composition may be 70% by mass or less, and may be 65% by mass or less , May be 60% by mass or less, or 58% by mass or less. Moreover, the sum total of the content of a plasticizer and a tackifier in a photocurable resin composition can be 0.5 mass% or more, may be 2 mass% or more, 4 mass% or more, 5 mass% or more, and 7 mass % Or more. A plasticizer and / or a tackifier may be used individually by 1 type, and may use 2 or more types together. When two or more types of plasticizers and / or tackifiers are used in combination, it is preferable that the total content of the plasticizers and / or tackifiers is within the above-described range.

<Other ingredients>

The photocurable resin composition is, in a range that does not impair the effects of the present technology, in addition to the components described above, for example, polymer components (polymer components other than the photoradical reactive components, plasticizers and tackifiers described above), oxidation You may further contain an inhibitor, a light stabilizer, a silane coupling agent, and the like. As the polymer component, for example, Hitroid 7927 (manufactured by Hitachi Chemical Co., Ltd.) can be used. This heater 7927 is a UV 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 contains the heater 7927, the content of the heater 7927 in the photocurable resin composition shall be 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, 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 commercially available products of the light stabilizer, for example, Adekastab LA-52 (manufactured by ADEKA) can be used. As a silane coupling, 3-acryloxypropyl trimethoxysilane, 3-methacryloxypropyl trimethoxysilane, 3-mercaptopropyl trimethoxysilane can be used, for example. As a commercial item of a silane coupling, KBM5103, KBM503, KBM803 (above, Shin-Etsu Silicone company make) can be used, for example.

<Step B>

In step B of the production method, the curable resin layer 2 is irradiated with light from a UV-LED as shown in FIG. 2 to form a temporary cured layer 5 as shown in FIG. 3. In step B, the first light having a peak in the range of wavelengths of 360 to 430 nm and the second light having a peak in the range of wavelengths of 200 to 345 nm are irradiated to the curable resin layer 2 formed in step A. .

The light irradiation in step B is preferably performed such that the reaction rate of the temporary cured layer 5 is 10 to 90%, more preferably 40 to 90%, and more preferably 70 to 90%. It is more preferable to carry out. The reaction rate is a numerical value defined by the ratio (consumption amount ratio) of the amount of the (meth) acryloyl group after light irradiation to the amount of the (meth) acryloyl group in the curable resin layer before light irradiation. It shows that hardening is progressing, so that the numerical value of this reaction rate is large. 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 layer after light irradiation (hardening number The absorption peak height (Y) of 1640 to 1620 cm ^-1 from the baseline in the FT-IR measurement chart of the layer 6) can be calculated by substituting in the following equation.

Reaction rate (%) = [(X-Y) / X] × 100

In the step B, a portion of the curable resin layer 2 in which oxygen inhibition occurs by irradiating the curable resin layer 2 with the first light having a peak in the wavelength range of 360 to 430 nm, specifically, the curable resin layer (2 It is preferable to irradiate the surface of) with the 1st light which has a peak in the range of wavelengths 360-430nm, and the 2nd light which has a peak in the range of wavelengths 200-345nm.

In step B, it is preferable to irradiate the light so that the integrated light amount of the first light having a peak in the range of wavelengths 360 to 430 nm is greater than the integrated light amount of the second light having a peak in the range of wavelengths of 200 to 345 nm. Thereby, the adhesive performance at the time of temporary hardening can be made more favorable. As an example, the integrated light amount of the first light having a peak in the range of wavelengths 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 range of wavelengths of 200 to 345 nm is 20 mJ / It is preferable that it is in the range of 2 cm 2 or more and less than 1000 mJ / cm 2. In the step B, it is preferable to irradiate, for example, light having an emission wavelength of 365 ± 5 nm under conditions of an illuminance of 100 to 500 Pa / cm 2 as the first light having a peak in the range of the wavelength of 360 to 430 nm. . Further, in the step B, as the second light having a peak in the wavelength range of 200 to 345 nm, for example, irradiating light having an emission wavelength of 280 ± 5 nm under conditions of an illuminance of 10 to 100 Pa / cm 2 desirable. As the UV-LED used in step B, for example, an LED having a peak emission wavelength in the range of 360 to 430 nm (eg, an emission wavelength of 365 ± 5 nm) and a peak emission wavelength of 200 to 345 nm (example As it can be used a device having an LED having a light emission wavelength of 280 ± 5 nm).

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

In this manufacturing method, it is preferable to prevent the liquid from flowing or deforming of the temporary cured layer 5 during the bonding operation in the step C described later. For example, in step B, before irradiating the curable resin layer 2 with the first light having a peak in the range of wavelengths of 360 to 430 nm and the second light having a peak in the range of wavelengths of 200 to 345 nm, It is preferable that light is irradiated so that the viscosity of the curable resin layer 2 is 20 Pa · S or more (cone plate rheometer, 25 ° C, cone and plate C35 / 2, rotation speed 10 rpm).

<Step C>

In step C, for example, as shown in FIG. 4, the front plate 4 and the image display member 1 are pasted through the temporary cured layer 5. For example, in Step C, the front plate 4 is pasted to the image display member 1 from the temporary hardened layer 5 side. The bonding can be performed, for example, by pressing at 10 to 80 ° C using a known crimping device.

The front plate 4 may be any one that has a light transmittance such that the image formed on the image display member 1 can be visually recognized. For example, plate materials such as glass, acrylic resin, polyethylene terephthalate, polyethylene naphthalate, and polycarbonate And sheet-like materials. These materials may be subjected to a hard coat treatment or antireflection treatment on one side or both sides. Physical properties such as the thickness and elastic modulus of the front plate 4 can be appropriately determined according to the purpose of use. Moreover, various sheets or film materials, such as a touch panel module, may be laminated on the front plate 4.

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

<Step D>

In the process D, the temporary cured layer 5 shown in FIG. 5 is irradiated with light through the front plate 4, for example, and the cured resin layer 6 as shown in FIG. 6 is formed. The temporary curing of the temporary cured layer 5 in the step D is to sufficiently cure the temporary cured layer 5 and bond the image display member 1 and the front plate 4 to be laminated. By performing step D, as shown in FIG. 6, an image display device 7 comprising an image display member 1, a cured resin layer 6, and a front plate 4 in this order is obtained.

The main curing (light irradiation) in 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. The type of light source, the output, the illuminance, and the amount of accumulated light when performing this curing are not particularly limited, and the photo-radical polymerization process conditions of (meth) acrylate by known ultraviolet irradiation can be employed. For example, ultraviolet irradiation is performed using an ultraviolet irradiator (metal halide lamp, high-pressure mercury lamp, UV-LED, etc.) under conditions of an illuminance of 50 to 300 Pa / cm 2 and an accumulated light amount of 1000 to 6000 mJ / cm 2 desirable. Particularly, in the step D, it is preferable to irradiate the first light having a peak in the range of the wavelength of 360 to 430 nm using UV-LEDs from the request of high lifespan performance of the ultraviolet irradiation device as described above.

Further, in step D, the temporary cured layer 5 is viewed by irradiating light to the temporary cured layer 5 between the light-shielding layer 3 of the front plate 4 and the image display member 1 as necessary. You may harden.

It is preferable that the transmittance | permeability of the visible light region of the cured resin layer 6 in the image display apparatus 7 obtained by this manufacturing method is 90% or more. By satisfying such a range, the visibility of the image formed on the image display member 1 can be made better. It is preferable that the refractive index of the cured resin layer 6 is substantially equal to the refractive index of the image display member 1 and the front plate 4. It is preferable that the refractive index of the cured resin layer 6 is 1.45 or more and 1.55 or less, for example. Thereby, the luminance and contrast of the video light from the image display member 1 can be increased to improve visibility. The thickness of the cured resin layer 6 can be, for example, about 25 to 200 μm.

According to the manufacturing method as described above, the adhesion performance during temporary curing can be improved.

In addition, in step 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 the side where the light-shielding layer 3 is formed. You may do it. Moreover, you may use the front plate which does not have the light-shielding layer 3 as a front plate.

Example

Hereinafter, embodiments of the present technology will be described. In addition, this technique is not limited to these Examples.

<Preparation of photocurable resin composition>

The photocurable resin composition was prepared by mixing each component uniformly in the compounding quantity (part by mass) shown in Table 1.

The symbol in Table 1 is the following compounds.

Urethane acrylate oligomer: Number average molecular weight 20000

CN9014: Urethane acrylate oligomer, manufactured by Satomer

Hitroid 7927: Hitachi Hwaseong Co., Ltd.

4HBA: 4-hydroxybutyl acrylate, manufactured by BASF

ISTA: isostearyl acrylate, manufactured by Osaka Organic Chemical Company

Miramer M210: hydroxypivalic acid neopentyl glycol diacrylate, manufactured by 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; Clearlon M105, manufactured by Yasuhara Chemical

GI-1000: Hydroxylated polybutadiene at both ends, manufactured by Nippon Soda Co., Ltd.

GI-3000: Hydroxylated polybutadiene at both ends, manufactured by 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

Irg184D: 1-hydroxy-cyclohexyl-phenyl-ketone, product name; Irgacure184, manufactured by BASF

MBF: phenyl glyoxylate, product name; IRGACURE MBF, manufactured by BASF

TZT: Product name; Esacure TZT, manufactured by Lamberti

[Example 1]

<Preparation of test sample using Resin A>

As shown in FIG. 7 (A), the photocurable resin composition 12 was slit from the slit nozzle 11 to a thickness of 33 µm from one side to the other side of the surface of the PET film 10 (130 mm thick). After coating, the applied photocurable resin composition 12 was irradiated with light having a peak at a wavelength of 365 nm so that the accumulated light amount from UV-LED13 was 500 mJ / cm 2. This light irradiation was performed in order to suppress liquid dripping of the applied photocurable resin composition. Thereby, the 1st layer curable resin layer 14A was formed. Next, as shown in Fig. 7 (B), after applying the photocurable resin composition 12 from the slit nozzle 11 to a thickness of 33 µm on the curable resin layer 14A, the applied photocurable resin The composition 12 was irradiated with light having a peak at a wavelength of 365 nm so that the accumulated light amount from UV-LED13 was 500 mJ / cm 2, thereby forming the second curable resin layer 14B. This light irradiation was also performed in order to suppress the liquid dripping of the applied photocurable resin composition. Next, as shown in FIG. 7 (C), the photocurable resin composition 12 was coated on the curable resin layer 14B from the slit nozzle 11 to a thickness of 33 μm, and then applied. The composition (12) was irradiated with light having a peak at a wavelength of 365 nm from UV-LED13 so that the accumulated light amount was 500 mJ / cm 2, thereby forming the third layer of curable resin layer 14C. This light irradiation was also performed in order to suppress the liquid dripping of the applied photocurable resin composition. Thereby, the laminated body on which the curable resin layer 14 of about 100 micrometers thickness was formed was obtained on the PET film 10.

As shown in FIG. 7 (D), for the curable resin layer 14 of the laminate, UV-LED (manufactured by CCS, a plurality of LEDs having an emission wavelength of 365 nm and a plurality of LEDs having an emission wavelength of 280 nm) From the device having an irradiation range of 80 mm × 80 mm), the light having a peak at a wavelength of 365 nm of 200 ㎽ / cm 2 intensity and the integrated light amount of 20 mJ / cm 2 so that the integrated light amount becomes 5000 mJ / cm 2 Light having a peak at a wavelength of 280 nm with an intensity of / cm 2 was irradiated. Thereby, the laminated body in which the temporary cured layer 15 was formed on the PET film 10 was obtained. The curing rate of the temporary cured layer 15 was about 80 to 90% as a result of finding the height of the absorption peak of 1640 to 1620 cm ^-1 from the baseline in the FT-IR measurement chart as an index.

As shown in FIG. 7 (E), the laminate was cut to have a width of 25 mm. As shown in FIG. 7 (F), the cut laminate was affixed to the slide glass 16 (25 mm wide and 1 mm thick). As shown in Fig. 7 (G), it was pressed using a 2 kg load roller 17 from the side surface of the laminate. Thereby, the PET film 10 and the slide glass 16 are bonded together through the test sample 18 shown in Fig. 7H, that is, the temporary cured layer 15 (10 mm × 25 mm, thickness 0.1 mm). Obtained test sample (18) was obtained.

<Measurement of shear strength of temporary cured layer>

The shear strength of the temporary cured layer 15 in the test sample 18 was measured by the method shown in FIG. 8. Specifically, using a table-top precision universal testing machine (manufactured by Shimadzu Corporation, Autograph), the PET film 10 positioned on the lower side of the test sample 18 is fixed with a jig 19, and positioned on the upper side The shear strength of the temporary cured layer 15 when the slide glass 16 was peeled through the jig 20 at a rate of 5 mm / min in the vertical direction was measured. 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 accumulated light amount of light irradiated on the curable resin layer 14 of the laminate was as shown in the following table, and the shear strength of the temporary cured layer in the test sample was measured. It was measured. The results are shown in Fig. 9 and Table 2.

[Example 7, Comparative Examples 3 to 5]

Using Resin B, a test sample was prepared in the same manner as in Example 1, except that the cumulative light amount of light irradiated on the curable resin layer 14 of the laminate was as shown in the following table, and temporary The shear strength of the cured layer was measured. The results are shown in Fig. 10 and Table 3.

[Example 8, Comparative Examples 6-8]

Using Resin C, a test sample was prepared in the same manner as in Example 1, except that the cumulative light amount of light irradiated on the curable resin layer 14 of the laminate was as shown in the table below, and the temporary test sample was The shear strength of the cured layer was measured. The results are shown in Fig. 11 and Table 4.

[Example 9, Comparative Examples 9-11]

Using Resin D, a test sample was prepared in the same manner as in Example 1, except that the cumulative light amount of light irradiated onto the curable resin layer 14 of the laminate was as shown in the following table, and the temporary test sample The shear strength of the cured layer was measured. In addition, in Comparative Example 10, only light having a peak at a wavelength of 365 nm of 600 Pa / cm 2 intensity was irradiated from the UV-LED so that the accumulated light amount was 6000 mJ / cm 2. The results are shown in Fig. 12 and Table 5.

[Example 10, Comparative Example 12]

Using Resin E, a test sample was prepared in the same manner as in Example 1, except that the cumulative light amount of light irradiated onto the curable resin layer 14 of the laminate was as shown in the following table, and temporary The shear strength of the cured layer 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 process of forming a temporary cured layer by irradiating light from UV-LED to the curable resin layer peaked in the range of wavelengths from 360 to 430 nm. It has been found that the shear strength of the temporary cured layer is good, that is, the adhesion performance during temporary curing is good by including the first light having and the second light having a peak in the range of wavelengths of 200 to 345 nm. Moreover, 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 of the metal halide lamp irradiation can be realized. In addition, from the results of Examples 1 to 10, it was found that the tendency to improve the adhesion performance during temporary curing does not depend on the composition ratio of the photocurable resin composition.

From the results of Examples 1 to 6, in the case of using the resin A, in the step of forming a temporary cured layer by irradiating light from the UV-LED to the curable resin layer, the agent having a peak in the range of wavelength 360 to 430 nm The integrated light amount of 1 light 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 range of 200 to 345 nm is preferably 20 mJ / cm 2 or more and less than 1000 mJ / cm 2, and the wavelength It turned out that it is more preferable that the accumulated light quantity of the 2nd light which has a peak in the range of 200-345 nm is 500 mJ / cm <2> or more and less than 1000 mJ / cm <2>.

In Examples 8 and Comparative Examples 6 to 8, since a resin C having a relatively mild reactivity and containing a large proportion of plasticizer was used, the shear strength at the time of temporary curing compared to that of other resins was used. It tended not to be expressed well, but it was found that in Example 8, the shear strength was more than twice that of Comparative Examples 6 to 8.

In Comparative Examples 1 to 12, the light irradiated in the process of forming a temporary cured layer by irradiating light from UV-LED on the curable resin layer, only light having a peak in the range of wavelength 360 to 430 nm, or wavelength 200 to Since only light having a peak in the range of 345 nm was included, it was found that the adhesion performance during temporary curing was not good.

In Comparative Example 4, the integrated light amount of light having a peak in the range of wavelengths 360 to 430 nm from UV-LED was set to 8000 mJ / cm 2, but light having a peak in the range of wavelengths 200 to 345 nm was not irradiated. , It was found that the shear strength was very low as compared with Example 7. Moreover, in Comparative Example 5, in which only light having a peak was irradiated in the range of wavelengths of 200 to 345 nm, it was found that the shear strength was very low as compared with Example 7. From these results, considering the curability of the core portion of the curable resin layer, in the step of forming the temporary cured layer, light having a peak in the range of wavelengths of 360 to 430 nm and light having a peak in the range of wavelengths of 200 to 345 nm It was found that it is essential to use a combination.

In Comparative Example 10, the illuminance of light having a peak in the range of 360 to 430 nm from UV-LED was increased to 600 Pa / cm 2, and the integrated light amount was increased to 6000 mJ / cm 2, but the wavelength was 200 to 345 nm Since light having a peak in the range of was not irradiated, it was found that the result of measuring the shear strength was lower than that of Example 9.

<Measurement of shear strength of the cured resin layer>

[Example 9-1]

The temporary hardened layer of the test sample in Example 9 was irradiated with light having a strength of 200 Pa / cm 2 so that the accumulated light amount was 5000 mJ / cm 2 using a metal halide lamp with a conveyor (manufactured by USIO). Thus, the temporary 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 in the same manner as the temporary cured layer described above. The results are shown in FIG. 14. In addition, N1 to N4 in FIG. 14 prepare four samples for each test, and show the results of measuring the shear strength for the four samples for testing. The average (*) in FIG. 14 represents the average value of the measurement results of the shear strengths of N1 to N4.

[Example 9-2]

For the temporary cured layer of the test sample in Example 9, UV-LED was used to surface irradiate the light having a peak at a wavelength of 365 nm of 200 Pa / cm 2 intensity so that the accumulated light amount becomes 5000 mJ / cm 2. Thereby, the temporary 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 in the same manner as the temporary cured layer described above. The results are shown in FIG. 14.

[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. 14.

[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. 14.

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 adhesive strength (influence of oxygen inhibition) occurs remarkably during temporary curing, while the difference in chemical adhesive strength is further added after the main curing.

1: image display member
2: Curable resin layer
3: Light-shielding layer
4: Front panel
5: temporary hardened layer
6: Cured resin layer
7: Image display device
10: PET film
11: slit nozzle
12: photocurable resin composition
13: UV-LED
14: curable resin layer
15: temporary hardened layer
16: slide glass
17: load roller
18: test sample
19: jig
20: jig

Claims (9)

Step A of forming a curable resin layer made of a photocurable resin composition on the front panel or the surface of the image display member,
Process B for forming a temporary cured layer by irradiating light from the UV-LED to the curable resin layer,
A process C for bonding the front panel and the image display member through the temporary cured layer,
Having a step D of irradiating the temporary cured layer through the front plate and forming a cured resin layer,
The light irradiated in step B includes a first light having a peak in the range of wavelengths of 360 to 430 nm and a second light having a peak in the range of wavelengths 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 a portion of the curable resin layer where oxygen inhibition occurs. According to claim 1,
In the step B, a method of manufacturing an image display device, wherein the curable resin layer is irradiated with the first light and the second light so that the accumulated light amount of the first light is greater than the accumulated light amount of the second light. The method of claim 1 or 2,
In the said process B, the manufacturing method of the image display apparatus which irradiates the said 1st light and the said 2nd light with respect to the surface of the said curable resin layer. The method according to any one of claims 1 to 3,
The manufacturing method of the image display apparatus whose thickness of the said curable resin layer is 25-350 micrometers. The method according to any one of claims 1 to 4,
In the step B, the integrated light amount of the first light is in the range of 2000 to 5000 mJ / cm 2, and the integrated light amount of the second light is in a range of 20 mJ / cm 2 or more and less than 1000 mJ / cm 2. The method according to any one of claims 1 to 5,
The said photocurable resin composition contains the photoradical reactive component, a photoinitiator, and a plasticizer and at least 1 sort (s) of a tackifier component, The manufacturing method of the image display apparatus. The method of claim 6,
The said photoradical reactive component contains the (meth) acrylate oligomer and (meth) acrylate monomer, The manufacturing method of an image display apparatus. The method according to claim 6 or 7,
The photopolymerization initiator comprises at least one of an alkylphenone-based photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator, an benzophenone-based photopolymerization initiator, and an intramolecular hydrogen drawing type photopolymerization initiator. The method according to any one of claims 6 to 8,
The said photocurable resin composition totals 30 to 90 mass% of the said photoradical reactive component, 2 to 6 mass% of the said photoinitiator, and 5 to 58 mass% of at least 1 type of the said plasticizer and the said tackifier component. The manufacturing method of the image display apparatus containing.

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