JP2023029478A - Laminate manufacturing method - Google Patents

Abstract

The present invention provides a method for producing a laminate that can suppress liquid dripping when a photocurable resin composition is applied. [Solution] This manufacturing method includes a step (A) of forming a temporarily cured resin layer 13 in which a photocurable resin composition 6 is temporarily cured on the surface of a light transmitting member 3; , a step (B) of bonding the image display member 2 with the temporary hardening resin layer 13, and a step (C) of irradiating the temporary hardening resin layer 13 with light to fully cure it. In step (A), the photocurable resin composition 6 is coated on the surface of the light-transmitting member 3, and the photocurable resin composition 6 is coated with the photocurable resin composition 6 to prevent deformation of the coated photocurable resin composition 6. The method includes a step (A1) of irradiating light, and a step (A2) of further irradiating light so that the photocurable resin composition 6 irradiated with light in step (A1) has a predetermined reaction rate. [Selection diagram] Figure 5

Description

The present technology relates to a method for manufacturing a laminate.

Image display devices used in information terminals such as smart phones and tablet PCs are manufactured by, for example, the following method (see Patent Document 1, for example).

First, as shown in FIG. 9, a liquid photocurable resin composition is applied from the nozzle 101A of the application portion 101 to the surface of the light-transmissive member (first member) 3 having the light-shielding layer 5 formed on the periphery. Apply 6. Next, as shown in FIGS. 10 and 11 , the photocurable resin composition 6 applied to the surface of the light-transmitting member 3 is irradiated with light from a light irradiation unit 102 to form a temporary cured resin layer 103 . Next, as shown in FIG. 11, the light-transmissive member 3 and the image display member (second member) 2 are pasted together with the provisionally cured resin layer 103 interposed therebetween. Next, the temporarily cured resin layer 103 is irradiated with light to be fully cured to form a cured resin layer. An image display device is thus obtained.

As described above, the manufacturing method shown in FIGS. 9 to 11 performs temporary curing after applying the photocurable resin composition 6, so that the photocurable resin composition 6 is laminated while maintaining the application shape. becomes possible.

Moreover, as another manufacturing method, there is a method of laminating the applied photocurable resin composition without pre-curing it. In this method, for example, as shown in FIG. The member 3 and the image display member 2 are pasted together with the photocurable resin composition 6 interposed therebetween. Then, the photocurable resin composition 6 is fully cured.

Furthermore, as another manufacturing method, a method using an optical clear adhesive sheet (OCA) instead of using a liquid photocurable resin composition is also available. In this method, for example, as shown in FIG. 13(A), an optically transparent adhesive sheet 104 is attached to the surface of the light transmissive member 3, and as shown in FIGS. 13(B) and 13(C), the light transmissive member 3 and the image display member 2 are pasted together with the transparent adhesive sheet 104 interposed therebetween. Then, the transparent adhesive sheet 104 is fully cured.

By the way, in the method of laminating the photocurable resin composition after temporary curing as described above, as shown in FIG. When the coating is applied, dripping tends to occur at the edges of the applied photocurable resin composition. This dripping causes the occurrence of an unbonded region R as shown in FIG. . If the non-bonded area R occurs, it becomes difficult to increase the bonded area in, for example, a narrow-framed liquid crystal display panel. In addition, as shown in FIGS. 12 (A) to (C), a method of laminating the photocurable resin composition in a liquid state without temporary curing, or as shown in FIGS. 13 (A) to (C), optical In the method using the adhesive sheet 104, it is considered that the problem of the non-adhered region R is less likely to occur because the liquid is less likely to sag.

JP 2013-151151 A

The present technology has been proposed in view of such conventional circumstances, and provides a method for manufacturing a laminate that can suppress dripping when a photocurable resin composition is applied.

A method for manufacturing a laminate according to the present technology includes a step (A) of forming a temporarily cured resin layer obtained by temporarily curing a photocurable resin composition on the surface of a first member, the first member, and the second member. A step (B) of laminating the members via a temporary hardening resin layer, and a step (C) of irradiating the temporary hardening resin layer with light to perform main curing, and the step (A) is the first A step (A1) of applying a photocurable resin composition to the surface of a member and irradiating the photocurable resin composition with light to prevent deformation of the applied photocurable resin composition; and a step (A2) of further irradiating the photocurable resin composition irradiated with light in step (A2) so that the photocurable resin composition has a predetermined reaction rate.

According to the present technology, since the step of forming the temporary cured resin layer includes irradiating the photocurable resin composition with light to prevent deformation of the applied photocurable resin composition, the photocurable resin It is possible to suppress dripping when the composition is applied.

FIG. 1 is a cross-sectional view showing an example of a laminate obtained by a laminate manufacturing method. FIG. 2 is a graph showing the measurement results of the height of the coated surface of the photocurable resin composition according to the elapsed time from application of the photocurable resin composition to light irradiation. FIG. 3 is a graph showing measurement results of the height of the coated surface of the photocurable resin composition according to the coating thickness of the photocurable resin composition. FIG. 4 is a block diagram showing a configuration example of a coating device. FIG. 5 is a diagram for explaining an example of step (A1) in the method for manufacturing a laminate. FIG. 6 is a diagram for explaining an example of step (A2) in the method for manufacturing a laminate. FIG. 7 is a graph showing changes in the amount of dripping with respect to the coating thickness of the photocurable resin composition and the time from coating of the photocurable resin composition to light irradiation. FIG. 8 is a graph showing changes in the amount of liquid dripping due to differences in the viscosity of the photocurable resin composition. FIG. 9 is a perspective view showing an example of a step of applying a photocurable resin composition to the surface of a light transmissive member. FIG. 10 is a perspective view showing an example of a process of irradiating a photocurable resin composition with light to form a temporary cured resin layer. FIG. 11 is a perspective view showing an example of a process of bonding a light-transmitting member and an image display member together with a temporary cured resin layer interposed therebetween. 12A and 12B are diagrams for explaining an example of a method for manufacturing an image display device, and FIG. 12A is a perspective view showing an example of a step of applying a photocurable resin composition to the surface of a light-transmissive member. 12(B) and 12(C) are cross-sectional views showing an example of a process of laminating a light-transmissive member and an image display member via a photocurable resin composition. 13A and 13B are diagrams for explaining an example of a method for manufacturing an image display device, and FIG. 13A is a perspective view showing an example of a process of attaching an optically transparent adhesive sheet to the surface of a light transmissive member. 13(B) and 13(C) are cross-sectional views showing an example of a process of laminating a light-transmissive member and an image display member via an optically transparent adhesive sheet. 14A and 14B are cross-sectional views showing an example of a process of bonding a light-transmitting member and an image display member via a temporary cured resin layer, and FIG. 14A is a cross-sectional view for explaining an example of liquid dripping 14B is a sectional view for explaining an example of the unbonded region R. FIG.

<Laminate>
In the method for manufacturing a laminate according to the present embodiment, for example, as shown in FIG. 2) obtains the image display device 1 (laminate) laminated with the cured resin layer 4 interposed therebetween.

Examples of the image display member 2 include a liquid crystal display panel, an organic EL display panel, a plasma display panel, and a touch panel. Here, 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 light-transmitting member 3 may have light-transmitting properties such that an image formed on the image display member 2 can be visually recognized. Examples thereof include plate-like materials and sheet-like materials such as glass, acrylic resin, polyethylene terephthalate, polyethylene naphthalate, and polycarbonate. At least one surface of these materials may be subjected to hard coating treatment, antireflection treatment, or the like. Physical properties such as the thickness and elastic modulus of the light-transmitting member 3 can be appropriately determined according to the purpose of use. Further, the light transmitting member 3 includes not only a member having a relatively simple structure as described above, but also a laminate of various sheets or film materials such as a touch panel module.

The light-shielding layer 5 is provided to improve the contrast of an image, and can be formed by, for example, applying a paint colored in black or the like by a screen printing method or the like, followed by drying and curing. The thickness of the light shielding layer 5 is usually 5 to 100 μm.

The refractive index of the cured resin layer 4 is preferably substantially the same as the refractive index of the image display member 2 and the light-transmitting member 3, and is preferably 1.45 or more and 1.55 or less, for example. Thereby, the brightness and contrast of the image light from the image display member 2 can be increased, and the visibility can be improved. Moreover, it is preferable that the transmittance of the cured resin layer 4 exceeds 90%. Thereby, the visibility of the image formed on the image display member 2 can be improved. The thickness of the cured resin layer 4 is preferably 50 to 150 μm, for example.

The cured resin layer 4 can be formed using a liquid photocurable resin composition 6 that is transparent and curable with ultraviolet light or visible light. The photocurable resin composition 6 may be in any state such as liquid or gel, and is preferably liquid. Here, the photocurable resin composition 6 preferably exhibits a viscosity of 0.01 to 100 Pa·s at 25° C. as measured by a Brookfield viscometer. In the method for manufacturing a laminate according to the present embodiment, even when a photocurable resin composition having a viscosity in the range of 1000 to 60000 mPa s at 25 ° C. is used, for example, when the photocurable resin composition is applied, Liquid dripping can be suppressed.

An example of the photocurable resin composition 6 that can be used in this production method will be described. The photocurable resin composition 6 contains, for example, a (meth)acrylate oligomer, a (meth)acrylate monomer, a photopolymerization initiator, and a softening agent. In addition, the photocurable resin composition 6 may further contain components other than these components within a range that does not impair the effects of the present technology. As used herein, (meth)acrylate includes both acrylate and methacrylate.

A (meth)acrylate oligomer is used as a base material for the photocurable resin composition 6 . As the (meth)acrylate oligomer, for example, a (meth)acrylate oligomer having a skeleton of polyurethane, polyisoprene, polybutadiene, or the like can be used. Specific examples of the (meth)acrylate oligomer having a polyurethane skeleton include aliphatic urethane acrylate (EBECRYL230, manufactured by Daicel Allnex). Further, as a specific example of the (meth)acrylate oligomer having a polyisoprene skeleton, there is an esterified product of a maleic anhydride adduct of a polyisoprene polymer and 2-hydroxyethyl methacrylate (UC102, manufactured by Kuraray Co., Ltd.). mentioned.

The (meth)acrylate monomer is used as a reactive diluent for imparting sufficient reactivity, coatability, etc. to the photocurable resin composition 6 . Examples of (meth)acrylate monomers include 2-hydroxypropyl (meth)acrylate, benzyl acrylate, dicyclopentenyloxyethyl (meth)acrylate, isobornyl (meth)acrylate, octyl (meth)acrylate and the like.

A known photopolymerization initiator can be used as the photopolymerization initiator. For example, 1-hydroxy-cyclohexyl phenyl ketone (Irgacure 184, manufactured by BASF), 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propyronyl)benzyl]phenyl}-2- Methyl-1-propan-1-one (Irgacure 127, manufactured by BASF), benzophenone, acetophenone and the like can be mentioned.

A softening agent consists of at least 1 sort(s) of a liquid plasticizer and a tackifier. The liquid plasticizer itself does not photo-cure when irradiated with ultraviolet rays, gives flexibility to the cured resin layer or temporary cured resin layer after photocuring, and reduces the cure shrinkage rate of the cured resin layer or temporary cured resin layer. It is something that makes Examples of liquid plasticizers include polybutadiene-based plasticizers, polyisoprene-based plasticizers, phthalate-based plasticizers, and adipate-based plasticizers.

The tackifier imparts flexibility to the cured resin layer or temporary cured resin layer after photocuring, and improves the initial adhesive strength (so-called tackiness) of the cured resin layer or temporary cured resin layer. Examples of tackifiers include terpene resins such as terpene resins, terpene phenol resins, and hydrogenated terpene resins, rosin resins such as natural rosin, polymerized rosin, rosin esters, and hydrogenated rosins, and petroleum resins such as polybutadiene and polyisoprene. etc.

The photocurable resin composition can be prepared by uniformly mixing the components described above according to a known mixing method. Commercially available photocurable resin compositions include, for example, trade names “LCR1000-DM”, “HSVR600” and “HSVR330” (manufactured by Dexerials Corporation).

<Method for manufacturing laminate>
This manufacturing method has the following steps (A) to (C).
Step (A): A temporarily cured resin layer is formed by temporarily curing a photocurable resin composition on the surface of the first member.
Step (B): The first member and the second member are bonded together with the provisionally cured resin layer interposed therebetween.
Step (C): The temporarily cured resin layer is irradiated with light to be fully cured.

Moreover, the step (A) has the following steps (A1) and (A2).
Step (A1): A photocurable resin composition is applied to the surface of the first member, and the photocurable resin composition is irradiated with light to prevent deformation of the applied photocurable resin composition.
Step (A2): The photocurable resin composition irradiated with light in step (A1) is further irradiated with light so as to achieve a predetermined reaction rate.

Thus, in the present production method, the step (A) of forming the temporary cured resin layer prevents deformation of the applied photocurable resin composition (at least deformation of the edge of the applied photocurable resin composition). and irradiating the photocurable resin composition with light. This makes it possible to suppress dripping when the photocurable resin composition is applied. In particular, in this production method, dripping can be suppressed even when a photocurable resin composition having a relatively low viscosity is used. This manufacturing method is suitable, for example, when a liquid crystal display panel having a narrow frame (for example, a width of 1 mm or less) is used.

FIG. 2 is a graph showing the measurement results of the height of the coated surface of the photocurable resin composition according to the elapsed time from application of the photocurable resin composition to light irradiation. FIG. 3 is a graph showing measurement results of the height of the coated surface of the photocurable resin composition according to the coating thickness of the photocurable resin composition. The vertical axis in FIGS. 2 and 3 represents the coating thickness (mm) of the photocurable resin composition. The horizontal axis in FIGS. 2 and 3 represents the distance (mm) from one end in the longitudinal direction of the light transmissive member to which the photocurable resin composition is applied. Here, the coating thickness of the photocurable resin composition is measured, for example, using a known displacement sensor that measures the height by irradiating the coated surface of the photocurable resin composition with a laser, ultrasonic waves, or the like. be able to.

From the results shown in FIG. 2, the shorter the elapsed time from the application of the photocurable resin composition to the surface of the light-transmitting member to the light irradiation, 15 seconds, 10 seconds, and 5 seconds, the more liquid dripped. It can be seen that there is a tendency to decrease Further, from the results shown in FIG. 3, it can be seen that dripping tends to be suppressed as the coating thickness of the photocurable resin composition becomes thinner, such as 250 μm, 175 μm, and 100 μm.

From the above results, it is considered possible to suppress dripping by, for example, applying a photocurable resin composition at an ultra-high speed and then immediately precuring the composition. However, this method requires an area-type light irradiator and a coating device (robot) capable of high-speed, high-precision driving. becomes very high.

Further, from the above results, a light irradiation unit (for example, an ultraviolet ray irradiator) is placed in the vicinity of the application unit (nozzle) for applying the photocurable resin composition, and light irradiation ( Temporary curing) is thought to be ideal. However, this method is not necessarily effective for all photocurable resin compositions. For example, in the case of using a photocurable resin composition having a relatively slow curing reaction, there is a possibility that the optimum pre-curing conditions cannot be obtained unless the coating speed of the photocurable resin composition is extremely lowered.

In addition, the optimum amount of light irradiation varies depending on the type of photocurable resin composition. This is because the strength of the photocurable resin composition after main curing, the presence or absence of unevenness, etc. are affected by the state of temporary curing.

Considering the circumstances as described above, in the present manufacturing method, the step of forming the temporarily cured resin layer is performed at least twice. First, in the first temporary curing (step (A1)), the photocurable resin composition is irradiated with light in order to prevent deformation of the photocurable resin composition. That is, the photocurable resin composition is temporarily cured to such an extent that the applied shape can be maintained. As a result, dripping of the applied photocurable resin composition is suppressed. Then, in the second temporary curing (step (A2)), light is further irradiated so that the temporarily cured resin layer obtained in the first temporary curing has a predetermined reaction rate. As a result, a temporarily cured resin layer that is temporarily cured to such an extent that lamination can be performed while maintaining the applied shape of the photocurable resin composition is obtained.

According to this production method, when a photocurable resin composition is applied without using an area-type light irradiation device or a coating device capable of high-speed and high-precision driving, the applied photocurable resin composition It is possible to suppress the occurrence of liquid dripping at the end of the. Therefore, it is possible to suppress dripping when the photocurable resin composition is applied without increasing restrictions in terms of facilities.

Next, details of each step of the production method, that is, step (A1), step (A2), step (B), and step (C) will be described.

[Step (A1)]
The application of the photocurable resin composition in step (A1) can be performed by various commonly used application methods. In the step (A1), for example, as shown in FIG. 4, a coating device including a coating section 7, a light irradiation section 8, and a control section 9 can be used.

The application unit 7 includes, for example, a storage unit (not shown) that stores the photocurable resin composition 6, and a slit-shaped nozzle 7A (see FIGS. 5 and 6) that discharges the photocurable resin composition 6. , and a pump (not shown) for pushing out the photocurable resin composition 6 stored in the storage section to the nozzle 7A. In the application portion 7, for example, as shown in FIG. 9, the width of the nozzle 7A is wider than the width of the region 3S surrounded by the light shielding layer 5 on the surface of the light transmissive member 3. As shown in FIG. That is, the nozzle 7A has a width that straddles the regions 3S and the light shielding layers 5 formed at both ends of the light transmissive member 3 in the width direction. Thereby, the coating part 7 can apply the photocurable resin composition 6 across the regions 3S and the light shielding layers 5 formed at both ends of the light transmissive member 3 in the width direction.

It is preferable that the light irradiation section 8 is arranged in the vicinity of the application section 7 at a position where the nozzle 7A of the application section 7 is not irradiated with light. With such an arrangement, it is possible to prevent the tip portion of the nozzle 7A from hardening with the cured product of the photocurable resin composition 6 . As the light irradiator 8, for example, an ultraviolet irradiator can be used.

The control unit 9 relatively moves the coating unit 7 and the light irradiation unit 8 and the light transmissive member 3 . As a result, the photocurable resin composition 6 is applied from one end side to the other end side of the surface of the light transmissive member 3, and the applied photocurable resin composition 6 is irradiated with light.

As a specific example of step (A1), as shown in FIGS. It is preferable to irradiate the applied photocurable resin composition 6 with light from the light irradiation unit 8 while applying the photocurable resin composition 6 from the application unit 7 from 3A to the other end 3B. This makes it possible to more effectively suppress dripping when the photocurable resin composition is applied. In step (A1), the photocurable resin composition 6 is applied from one end side 3A to the other end side 3B of the surface of the light-transmitting member 3 without moving the stage on which the light-transmitting member 3 is placed. Meanwhile, the application section 7 and the light irradiation section 8 may be moved so as to irradiate the applied photocurable resin composition 6 with light.

In the step (A1), the elapsed time from the application of the photocurable resin composition 6 on the surface of the light-transmitting member 3 to the irradiation with light (hereinafter also referred to as “time from application to irradiation with light”) is , from the viewpoint of suppressing dripping of the photocurable resin composition 6, the shorter the better. For example, the time from application to light irradiation is preferably within 5 seconds.

When the light-shielding layer 5 is formed on the periphery of the surface of the light-transmitting member 3 , the coating thickness of the photocurable resin composition 6 is preferably thicker than the thickness of the light-shielding layer 5 . Specifically, 1.2 to 50 times (more preferably 2 to 30 times) the thickness of the light shielding layer 5 is applied to the entire surface of the light transmissive member 3 on the side where the light shielding layer is formed, including the surface of the light shielding layer 5 . is preferably applied to a thickness of A more specific coating thickness is preferably 25 to 350 μm, more preferably 50 to 150 μm.

The light irradiation conditions in step (A1) are preferably such that the curing rate of the temporarily cured resin layer 12 obtained after light irradiation in step (A1) is 40 to 50%, for example. Here, the curing rate is the ratio (consumption ratio) of the amount of (meth)acryloyl groups present after light irradiation to the amount of (meth)acryloyl groups present in the photocurable resin composition before light irradiation. is a defined number. The larger the value of this curing rate, the more advanced the curing. Specifically, the curing rate is the absorption peak height (X) from 1640 to 1620 cm ⁻¹ from the baseline in the FT-IR measurement chart of the photocurable resin composition 6 before light irradiation, and the light after light irradiation. The absorption peak height (Y) from 1640 to 1620 cm ⁻¹ from the baseline in the FT-IR measurement chart of the curable resin composition (temporary cured resin layer 12) can be calculated by substituting in the following formula. can.
Curing rate (%) = [(XY) / X] × 100

As for the light irradiation conditions, the type of light source, output, illuminance, integrated light amount, etc. are not particularly limited as long as the curing rate of the temporary cured resin layer 12 is preferably 40 to 50%.

[Step (A2)]
In step (A2), for example, by relatively moving the light irradiation unit 8 and the light-transmitting member 3, the temporarily cured resin layer is formed from one end side to the other end side of the surface of the light-transmitting member 3. is irradiated with light. As a specific example of step (A2), as shown in FIGS. 6A to 6C, the stage on which the light transmissive member 3 is placed is moved in the direction of the arrow, and one end of the surface of the light transmissive member 3 is moved. A method of irradiating the temporarily cured resin layer 12 with light from the light irradiation unit 8 from the side 3A to the other end 3B may be used. As another method, in step (A2), the temporary curing resin is applied from one end side 3A to the other end side 3B of the surface of the light-transmitting member 3 without moving the stage on which the light-transmitting member 3 is placed. The light irradiation section 8 may be moved so as to irradiate the layer 12 with light.

The light irradiation conditions in step (A2) are preferably such that the curing rate of the temporarily cured resin layer 13 obtained after light irradiation in step (A2) is 90% or less, for example. Here, the hardening rate is synonymous with the hardening rate described above. As for the light irradiation conditions, the type of light source, output, illuminance, integrated light amount, etc. are not particularly limited as long as the curing rate of the temporary cured resin layer 13 is preferably 90% or less.

[Step (B)]
In step (B), as shown in FIGS. 14A and 14B, the image display member 2 and the light-transmitting member 3 are bonded together with the provisionally cured resin layer 13 interposed therebetween. The lamination can be performed by applying pressure at 10 to 80° C. using a known crimping device, for example. From the viewpoint of ease of pressing when the image display member 2 and the light-transmitting member 3 are bonded together, for example, the angle of the convex portion at the end of the surface of the temporarily cured resin layer 13 shown in FIG. Preferably.

[Step (C)]
In the step (C), the temporary hardening resin layer 13 is irradiated with light, and the temporary hardening resin layer 13 is fully cured. Thereby, the cured resin layer 4 (see FIG. 1) is formed, and the laminate 1 is obtained.

The light irradiation in step (C) is preferably performed so that the curing rate of the cured resin layer 4 is 90% or more, more preferably 95% or more. Here, the hardening rate is synonymous with the hardening rate described above. As for the light irradiation conditions, the type of light source, output, illuminance, integrated light amount, etc. are not particularly limited as long as the curing rate of the cured resin layer 4 is preferably 90% or more.

This production method may further include other processes other than the processes described above, as long as the effect of suppressing dripping when the photocurable resin composition is applied is not impaired. For example, after the step (C), a step of further irradiating light from the side surface of the laminate 1 may be included.

In this manufacturing method, the light transmissive member 3 having the light shielding layer 5 formed thereon is used, but the present invention is not limited to this example. For example, the light transmissive member 3 without the light shielding layer 5 may be used. Thus, dripping can be suppressed even when the photocurable resin composition is applied to the surface of the light-transmitting member on which the light-shielding layer is not formed.

In addition, in this manufacturing method, the photocurable resin composition 6 is applied to the surface of the light-transmitting member 3 on which the light-shielding layer 5 is formed, but the present invention is not limited to this. For example, the photocurable resin composition 6 may be applied to the surface of the image display member 2 .

Examples of the present technology will be described below. In this experimental example, a temporary hardening resin layer was formed on the surface of the light transmissive member, and the light transmissive member and the image display member were pasted together via the temporary hardening resin layer. The amount of liquid dripping at the edge of the temporarily cured resin layer after bonding was evaluated. The present technology is not limited to these examples.

[Experimental example 1]
A liquid photocurable resin composition (product name: HSVR600, viscosity: 4700 mPa·s, manufactured by Dexerials Corporation) was used as the photocurable resin composition. A glass plate with a light-shielding layer formed on the periphery was used as the light-transmitting member. This glass plate has a size of 45 (w) × 80 (l) × 0.4 (t) mm, and a 4 mm wide light-shielding layer is heat-cured on the entire periphery of the glass plate so that the dry thickness is 40 µm. type black ink (MRX ink, Teikoku Ink Mfg. Co., Ltd.) was applied by screen printing and dried. A liquid crystal display panel was used as an image display member.

After applying the photocurable resin composition 6 from the coating portion 101 from one end side to the other end side of the surface of the light transmitting member 3 as shown in FIG. 9, the photocurable resin composition coated as shown in FIG. The resin composition 6 was irradiated with light from the light irradiation unit 102 .

The coating thickness of the photocurable resin composition was set to 150 μm. Also, the time from the application of the photocurable resin composition on the surface of the light-transmitting member to the light irradiation was set to 30 seconds. The reaction rate of the temporarily cured resin layer after light irradiation was 70 to 90%.

Next, as shown in FIGS. 14A and 14B, the light transmissive member 3 and the image display member 2 were pasted together with the provisionally cured resin layer 13 interposed therebetween. Then, as shown in FIG. 14B, the distance of the unbonded region R after lamination was measured, and this distance was evaluated as the amount of liquid dripping. In addition, the distance of the non-adhered area|region R measured the distance of the double line seen in the edge part of the temporary hardening resin layer 13 after bonding the light transmissive member 3 and the image display member 2 together. This double line is due to liquid dripping. Also, the distance between the double lines is proportional to the amount of liquid dripping. The amount of liquid dripping in Experimental Example 1 was about 0.8 mm.

[Experimental example 2]
In Experimental Example 2, the same photocurable resin composition, light transmissive member and image display member as in Experimental Example 1 were used. In Experimental Example 2, as shown in FIGS. 5A to 5C, by moving the stage on which the light transmissive member 3 is placed in the direction of the arrow, the surface of the light transmissive member 3 is moved from one end side 3A. The photocurable resin composition 6 was applied from the application portion 7 over the other end side 3B, and the applied photocurable resin composition 4 was irradiated with light from the light irradiation portion 8 (step (A1)).

The coating thickness of the photocurable resin composition was set to 150 μm. In addition, the moving speed of the stage was set so that the time from the application of the photocurable resin composition on the surface of the light transmissive member to the light irradiation was 4 seconds. The reaction rate of the temporarily cured resin layer 12 after light irradiation was 40 to 50%.

Next, the stage was moved so that the positional relationship between the coating section 7, the light irradiation section 8, and the light transmissive member 3 was as shown in FIG. 6(A). Next, as shown in FIGS. 6A to 6C, the stage on which the light-transmitting member 3 is placed is moved in the direction of the arrow at a speed of 10 mm/sec, thereby changing the surface of the light-transmitting member 3. The temporarily cured resin layer 12 was irradiated with light from the one end side 3A to the other end side 3B (step (A2)). The reaction rate of the temporarily cured resin layer 13 after light irradiation was 70 to 90%.

Next, as shown in FIGS. 14A and 14B, the light-transmitting member 3 and the image display member 2 were pasted together with the temporarily cured resin layer 13 interposed therebetween, and the amount of liquid dripping was evaluated. The amount of liquid dripping in Experimental Example 2 was about 0.5 mm.

[Experimental example 3]
Evaluation was performed in the same manner as in Experimental Example 2, except that in the step (A1) of Experimental Example 2, the time from application to light irradiation was set to 2 seconds. The amount of liquid dripping in Experimental Example 3 was about 0.4 mm.

[Experimental example 4]
Evaluation was performed in the same manner as in Experimental Example 2, except that in the step (A1) of Experimental Example 2, the coating thickness of the photocurable resin composition was set to 100 μm. The amount of liquid dripping in Experimental Example 4 was about 0.4 mm.

[Experimental example 5]
Evaluation was performed in the same manner as in Experimental Example 2, except that in the step (A1) of Experimental Example 2, the coating thickness of the photocurable resin composition was set to 50 μm. The amount of liquid dripping in Experimental Example 5 was about 0.15 mm.

[Experimental example 6]
Experimental Example 1 except that a photocurable resin composition having a viscosity of 1400 mPa s was used as the photocurable resin composition, and the coating thickness of the photocurable resin composition was set to 100 μm. was evaluated in the same manner as The amount of liquid dripping in Experimental Example 6 was about 0.9 mm.

[Experimental example 7]
Evaluation was performed in the same manner as in Experimental Example 4, except that a photocurable resin composition having a viscosity of 1400 mPa·s was used as the photocurable resin composition. The amount of liquid dripping in Experimental Example 7 was about 0.6 mm.

[Experimental example 8]
Evaluation was performed in the same manner as in Experimental Example 6, except that a photocurable resin composition having a viscosity of 4700 mPa·s was used as the photocurable resin composition. The amount of liquid dripping in Experimental Example 8 was about 0.75 mm.

[Experimental example 9]
Evaluation was performed in the same manner as in Experimental Example 6, except that a photocurable resin composition having a viscosity of 8800 mPa·s was used as the photocurable resin composition. The amount of liquid dripping in Experimental Example 9 was about 0.4 mm.

[Experimental example 10]
Evaluation was performed in the same manner as in Experimental Example 4, except that a photocurable resin composition having a viscosity of 8800 mPa·s was used as the photocurable resin composition. The amount of liquid dripping in Experimental Example 10 was about 0.25 mm.

[Experimental example 11]
Evaluation was performed in the same manner as in Experimental Example 6, except that a photocurable resin composition having a viscosity of 50000 mPa·s was used as the photocurable resin composition. The amount of liquid dripping in Experimental Example 11 was about 0.2 mm.

[Experimental example 12]
Evaluation was performed in the same manner as in Experimental Example 4, except that a photocurable resin composition having a viscosity of 50000 mPa·s was used as the photocurable resin composition. The amount of liquid dripping in Experimental Example 12 was about 0.15 mm.

The results of Experimental Examples 1 to 5 are shown in FIG. The horizontal axis in FIG. 7 represents the coating thickness of the photocurable resin composition and the time (seconds) from coating to light irradiation in each experimental example. Moreover, the vertical axis in FIG. 7 represents the liquid dripping amount (mm).

From the results shown in FIG. 7, it was found that the shorter the time from application to light irradiation, the more the liquid dripping tends to be suppressed. Specifically, it was found that the time from application to light irradiation is preferably within 5 seconds.

Moreover, it turned out that there exists a tendency for liquid dripping to be suppressed, so that the coating thickness of a photocurable resin composition is thin. Specifically, it was found that the coating thickness of the photocurable resin composition is preferably 50 to 150 μm.

The results of Experimental Examples 4 and 6 to 12 are shown in FIG. The horizontal axis in FIG. 8 represents the viscosity (mPa·s) of the photocurable resin composition in each experimental example. Moreover, the vertical axis in FIG. 8 represents the liquid dripping amount (mm). From the results shown in FIG. 8, when a photocurable resin composition with a lower viscosity is used, it is cured twice (step (A1 ) and step (A2)) are highly effective in suppressing dripping. Even when a photocurable resin composition having a high viscosity is used as in Experimental Examples 11 and 12, Experimental Example 12, in which curing is performed twice, is higher than Experimental Example 11, in which curing is not performed twice. It was found that liquid dripping was suppressed.

REFERENCE SIGNS LIST 1 image display device 2 image display member 3 light transmissive member 4 cured resin layer 5 light shielding layer 6 photocurable resin composition 7 application section 7A nozzle 8 light irradiation section 9 control section 10 Coating device 11 Stage 12 Temporary cured resin layer 13 Temporary cured resin layer 101 Coating part 101A Nozzle 102 Light irradiation part 103 Temporary cured resin layer 104 Optically transparent adhesive sheet

Claims (9)

A step (A) of forming a temporarily cured resin layer obtained by temporarily curing a photocurable resin composition on the surface of the first member;
A step (B) of bonding the first member and the second member together with the temporary cured resin layer interposed therebetween;
and a step (C) of irradiating the temporarily cured resin layer with light for final curing,
The above step (A) is
The step of applying a photocurable resin composition to the surface of the first member and irradiating the photocurable resin composition with light to prevent deformation of the applied photocurable resin composition (A1) and,
A method for producing a laminate, comprising a step (A2) of further irradiating the photocurable resin composition irradiated with light in the step (A1) with light so that the reaction rate becomes a predetermined value. In the step (A1), by relatively moving the first member and the coating portion for coating the photocurable resin composition and the light irradiation portion disposed in the vicinity of the coating portion, the The laminate according to claim 1, wherein the photocurable resin composition is applied while applying the photocurable resin composition from one end side to the other end side of the surface of the first member, and the applied photocurable resin composition is irradiated with light. manufacturing method. 3. The laminate according to claim 1 or 2, wherein in the step (A1), the time from when the photocurable resin composition is applied to the surface of the first member to when it is irradiated with light is within 5 seconds. body manufacturing method. The method for producing a laminate according to any one of claims 1 to 3, wherein in the step (A1), the photocurable resin composition is applied so that the coating thickness is 50 to 150 µm. The method for producing a laminate according to any one of claims 1 to 4, wherein in the step (A1), a photocurable resin composition having a viscosity of 1000 to 60000 mPa·s is applied. The laminate according to any one of claims 1 to 5, wherein in the step (A1), light irradiation is performed so that the curing rate of the temporarily cured resin layer obtained in the step (A1) is 40 to 50%. manufacturing method. The laminate according to any one of claims 1 to 6, wherein in the step (A2), light irradiation is performed so that the curing rate of the temporarily cured resin layer obtained in the step (A2) is less than 90%. Production method. The first member or the second member is an image display member,
The method for producing a laminate according to any one of claims 1 to 7, wherein the laminate is an image display device. A coating device used in the method for manufacturing a laminate according to any one of claims 1 to 8,
An application portion for applying the photocurable resin composition,
a light irradiation unit disposed near the application unit;
and a control unit,
The control unit relatively moves the application unit and the light irradiation unit, and the first member, thereby causing the application unit to move from one end side to the other end side of the surface of the first member. While controlling to apply the photocurable resin composition to the surface of the first member, the light irradiation unit is the photocurable resin to prevent deformation of the applied photocurable resin composition A coating device that controls to irradiate the composition with light.

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