TWI549821B - A hardened resin composition, a laminate using the same, and a method for producing the layered product (1) - Google Patents

Description

Curing resin composition, laminate using the same, and method for producing laminate (1) Field of invention

The present invention relates to a curable resin composition suitable for surface material joining, a laminate in which a surface material is laminated using the curable resin composition, and a method of producing the laminate.

Background of the invention

In the display device in which the protective layer is laminated on the display element via the bonding resin layer, when the bonding resin layer is cured, stress generated by shrinkage of the bonding resin layer may affect the display element. If stress is applied to the display element, the following problem occurs.

‧ The display forming material (hereinafter referred to as "display material") in the display element is affected by stress, which may impair the uniformity of display. For example, in the case of a liquid crystal display element, the arrangement of the liquid crystal enclosed in the display element is disturbed by external stress, and the display spot is observed.

‧ When an optical film such as a viewing angle is used to improve the display quality on the surface of the substrate on the display surface side of the display element, the optical characteristics of the optical film may be locally changed due to stress, and the display may be damaged. The ambiguity of uniformity.

Further, since the bonding resin layer is provided on the inspection side of the display element, if bubbles are present in the cured bonding resin layer, the following problem occurs.

‧The emitted or reflected light from the display element will be messy due to air bubbles, which will greatly impair the image quality of the displayed image.

‧ When the display element does not display an image, the air bubbles remaining in the bonding resin layer through the protective sheet are more easily viewed, which may greatly deteriorate the quality of the product.

‧ The interfacial adhesion between the resin layer and the display element, or the interface between the resin layer and the protective sheet, is reduced.

A method of fabricating a display device having a laminated structure in which a transparent surface material is laminated on a display element is known, and a method as described below is known.

(1) After the liquid material is injected into the resin protective plate to be cured to form a bonding resin, or the roll-shaped bonding resin is attached to the resin protective plate in a degassed state, the liquid crystal cell is pushed from one end. A method of adhering and laminating in a degassed state. It is preferable to use a polyphthalocyanine gel as a raw material for the bonding resin (Patent Document 1).

(2) At a predetermined position of the glass protective plate, the display panel is temporarily fixed by the fixing member, and then the liquid resin material is injected into the space formed between the protective plate and the display panel in a reduced pressure state. And the method of hardening, thereby stratifying. It is preferable to use a polyoxyn resin for the liquid resin material (Patent Document 2).

Advanced technical literature Patent literature

Patent Document 1: Japanese Patent Laid-Open No. Hei 7-209635

Patent Document 2: Japanese Patent Laid-Open Publication No. 2006-58753

According to the findings of the inventors of the present invention, the elastic modulus of the bonding resin layer can be lowered by lowering the polarity and molecular weight of the resin forming the bonding resin layer. When the modulus of elasticity of the bonding resin layer existing between the display element and the transparent surface material is lowered, the stress generated during the hardening and contraction is reduced, and the influence on the display quality can be suppressed.

However, depending on merely reducing the modulus of elasticity of the bonding resin layer, there is a case where the force for fixing the display element and the transparent face material is insufficient. For example, when the display device is used in a vertical arrangement, the display element may have a temporal property. The possibility of offset or detachment on the transparent face material.

The present invention has been made in view of the above circumstances, and it is an object of the invention to provide a surface material which can be sufficiently fixed to each other when a surface layer is laminated and integrated by a resin layer composed of a cured product of a curable resin composition. Further, a curable resin composition which can reduce stress due to shrinkage during curing of the resin layer, and a laminate in which the surface material is laminated using the curable resin composition can be used.

In addition, it is an object of the present invention to provide a surface layer which is formed by laminating a resin layer composed of a cured product of a curable resin composition, and the surface materials can be sufficiently fixed to each other, and the cause can be reduced. A method of producing a laminate of a resin layer in the resin layer by sufficiently suppressing stress caused by shrinkage at the time of curing the resin layer.

The curable resin composition of the present invention is used in a laminate in which an uncured curable resin composition is held between at least one of a pair of transparent surface materials and cured. The curable resin composition is characterized in that the shear elastic modulus is 5 × 10 ² to 1 × 10 ⁵ Pa and the loss tangent is 1.4 or less at the time of dynamic viscoelasticity measurement after hardening.

It is preferable to contain the following curable compound (II) and the following non-curable oligomer (D): a curable compound (II): a curable compound which undergoes a curing reaction when the curable resin composition is cured. In one or more types, at least one of the curable compounds has a hydroxyl group that does not react when the curable resin composition is cured; and the non-curable oligomer (D): when the curable resin composition is cured An oligomer which does not undergo a curing reaction with the curable compound (II) and has 0.8 to 3 hydroxyl groups per molecule.

It is preferred that the curable compound (II) contains a monomer having a curable group and having a hydroxyl group.

Preferably, the curable compound (II) comprises: an oligomer (A') having a curable group and having a molecular weight of from 1,000 to 100,000; and a monomer (B') having a curable group and a molecular weight of 125. 600, and the monomer (B') contains a monomer (B3) having a hydroxyl group.

Preferably, the non-curable oligomer (D) is a polyoxyalkylene polyol, and the oligomer (A') is an amine compound synthesized using a polyoxyalkylene polyol and a polyisocyanate as a raw material. Acid ester oligomer.

Preferably, the oligomer (A') has an acrylic group, and at least a part of the monomer (B') has a methacryl group.

Preferably, the monomer (B3) contains a hydroxy methacrylate, and the hydroxy methacrylate has a hydroxyalkyl group having 1 to 2 hydroxyl groups and 3 to 8 carbon atoms.

It is preferred that the monomer (B') contains a monomer (B4) selected from the group consisting of alkyl methacrylates having an alkyl group having 8 to 22 carbon atoms.

It is preferable that the chain transfer agent is not contained or the chain transfer agent is contained, but the content thereof is 1 part by mass or less based on 100 parts by mass of the curable compound (II).

A photocurable curable resin composition is preferred.

The laminate provided by the present invention is formed by laminating a pair of face materials through a resin layer, and the resin layer is composed of a cured product of the cured resin composition of the present invention.

Preferably, at least one of the pair of face materials is a transparent face material.

Preferably, one of the pair of face materials is a transparent face material, and the other is a display element.

Preferably, the display element is a liquid crystal display element.

The method for producing a laminate of the present invention is for producing a laminate, and the laminate system to be produced includes a first face material and a second face material, and the first face material and the second face material are sandwiched between The resin layer and the sealing portion surrounding the resin layer, the manufacturing method includes the following steps (a) to (d):

(a) a step of applying a curable resin composition for forming a liquid seal portion containing a curable compound (I) and a polymerization initiator to a peripheral portion of the surface of the first face material to form an uncured seal portion;

(b) a step of supplying a curable resin composition for forming a resin layer composed of the curable resin composition of the present invention to a region surrounded by the uncured seal portion;

(c) The second surface material is superposed on the curable resin composition for forming a resin layer in a reduced pressure environment of 100 Pa or less, and the first surface material and the second surface are obtained from the curable resin composition for forming a resin layer. And a step of laminating the precursor sealed by the unhardened seal; and

(d) A step of curing the uncured seal portion and the curable resin composition for forming a resin layer in a state where the laminated precursor is placed under a pressure of 50 kPa or more.

Preferably, at least one of the first surface material and the second surface material is a transparent surface material.

Preferably, one of the first surface material and the second surface material is a transparent surface material, and the other is a display element.

The curable compound (I) is a photocurable compound, the curable resin composition for forming a sealing portion contains a photopolymerization initiator (C1), and the curable resin composition for forming a resin layer is In the step (d), the uncured seal portion and the curable resin composition for forming a resin layer are subjected to light irradiation.

According to the curable resin composition of the present invention, the pair of face materials can be sufficiently fixed by being held between the face materials and hardened, and the stress caused by shrinkage during hardening can be reduced.

According to the laminate of the present invention, the face material and the face material can be sufficiently fixed via the resin layer, and the stress generated by the shrinkage when the resin layer is cured can be reduced.

According to the method for producing a laminate of the present invention, the pair of face materials can be sufficiently fixed by the resin layer composed of the cured product of the curable resin composition of the present invention, and the shrinkage due to the curing of the resin layer can be reduced. The stress is generated, and the laminate can be produced while sufficiently suppressing the occurrence of bubbles in the resin layer.

According to the manufacturing method of the present invention, the laminated system of the present invention can sufficiently suppress the generation of bubbles in the resin layer between the display element and the protective sheet, and the display element and the protective sheet are sufficiently fixed and hardened via the resin layer. The stress at the time of shrinkage can be lowered, and a display device capable of preventing deterioration of display quality due to the stress can be obtained.

Simple illustration

Fig. 1 is a cross-sectional view showing an example of a display device for protecting a display element by a transparent surface material.

Fig. 2 is a plan view showing the display device of Fig. 1.

Fig. 3 is a plan view showing an example of the aspect of the step (a).

Fig. 4 is a cross-sectional view showing an example of the aspect of the step (a).

Fig. 5 is a plan view showing an example of the aspect of the step (b).

Fig. 6 is a cross-sectional view showing an example of the aspect of the step (b).

Fig. 7 is a cross-sectional view showing an example of the aspect of the step (c).

Fig. 8 is a cross-sectional view showing an example of the aspect of the step (d).

Form for implementing the invention

In the present invention, the definition is as follows.

In the display device, the transparent surface material that serves as the protective sheet of the display element is referred to as "surface material", and the display element is referred to as "back surface material".

The surface material and the back material are collectively referred to as "face material".

In the surface material, in the manufacturing method of the present invention, the surface portion in which the sealing portion is formed in the peripheral portion and the portion surrounded by the sealing portion is called the "first surface material", and the surface material is overlapped. The surface material on the curable resin composition is referred to as "second surface material".

The light transmissive surface material is called "transparent surface material".

A transparent surface material made of glass is called a "glass plate."

In the laminated system display device of the present invention, a pair of face material-based surface materials (a transparent surface material serving as a protective sheet) and a back surface material (display element), and a curing portion for forming a sealing portion, are provided. An embodiment in which the resin composition and the curable resin composition for forming a resin layer are photocurable resin compositions will be described.

<display device>

Fig. 1 is a cross-sectional view showing an example of a display device of the embodiment, and Fig. 2 is a plan view.

The display device 1 includes a transparent surface material 10 (second surface material (or first surface material)), a display element 50 (first surface material (or second surface material)), a resin layer 40, a sealing portion 42, and the like. a flexible printed circuit board 54 (FPC) and a light-shielding printing unit 55 (light-shielding portion) belonging to a surface material, the display element 50 belonging to a back surface material, and the resin layer 40 being composed of a transparent surface material 10 and The display element 50 is surrounded by a sealing portion 42 that surrounds the periphery of the resin layer 40. The flexible printed circuit board 54 is connected to the display element 50 and is mounted with a driving IC that activates the display element 50. 55 is formed on the peripheral portion of the transparent surface material 10.

In the display device 1, the light-shielding printing portion 55 is provided on the peripheral portion of the transparent surface material 10, and the area of the light-transmitting portion 56 surrounded by the light-shielding printing portion 55 is smaller than the area of the resin layer 40 surrounded by the sealing portion 42, the transparent surface The area of the material 10 is larger than the area of the display element 50, and the total area of the resin layer 40 and the sealing portion 42 is smaller than the respective areas of the transparent surface material 10 and the display element 50.

[surface material]

The surface material is a transparent surface material (protective plate) through which the display image of the display element can pass.

The transparent surface material is, for example, a glass plate or a transparent resin plate, and has high light transmittance, low birefringence, high planar precision, and resistance from the viewpoint of high transparency of emitted light and reflected light from a display element. From the viewpoints of surface scratch resistance and high mechanical strength, the glass plate is most preferable. In view of the fact that the light energy for hardening the photocurable resin composition is sufficiently penetrated, a glass plate is also preferable.

The material of the glass plate may be, for example, a glass material such as soda lime glass, and is preferably a high-through glass (glass-lined glass) having a lower iron content and less blue. For safety, tempered glass can also be used for the surface material.

The material of the transparent resin sheet is, for example, a resin material having high transparency (such as polycarbonate, polymethyl methacrylate, etc.).

In the transparent surface material, a surface treatment may be performed to enhance the interface adhesion force with the resin layer. The surface treatment method is, for example, a method of treating a surface of a transparent surface material with a decane coupling agent, or a treatment for forming a ruthenium oxide film by an oxidizing flame generated by a flame burner. In order to improve the contrast of the display image on the transparent surface material, an antireflection layer may be provided on the back surface of the joint surface with the resin layer. The antireflection layer can be provided by, for example, a method of directly forming an inorganic thin film on the surface of a transparent face material, or a method of bonding a transparent resin film provided with an antireflection layer to a transparent face material.

Further, for the purpose of image display, a part or the whole of the transparent surface material may be colored in advance or in a frosted glass shape to scatter light by scattering light or by fine unevenness or the like on the surface. In addition, an optical film or the like which is optically modulated by an optical film or a polarizing film as described above may be bonded to a transparent surface material to form an integrated body, and used as a transparent surface material.

The thickness of the transparent face material is usually 0.5 to 25 mm in terms of mechanical strength and transparency. The use of a television receiver for indoor use, a display for a PC, etc., is preferably 0.7 to 6 mm in terms of weight reduction of the display device, and is preferably 3 to 20 mm when used for outdoor display applications. For the transparent surface material, tempered glass can be used, and when the transparent surface material is thin, chemically strengthened glass can be used. The case of the transparent resin sheet is preferably 2 to 10 mm.

[back material]

The backing material is a display element.

The display element 50 of the illustrated example is a liquid crystal display in which a transparent surface material 52 provided with a color filter and a transparent surface material 53 provided with a TFT are bonded together and sandwiched by a pair of polarizing plates 51. Although an element is an example, the display element of this embodiment is not limited to the illustration.

The display element holds a display material that changes an optical state by an external electrical signal in a pair of electrodes in which at least one of them is a transparent electrode. Depending on the type of the display material, there are, for example, a liquid crystal display element, an EL display element, a plasma display element, an electronic ink type display element, and the like. Further, the display element has a structure in which a pair of face materials are bonded and at least one of the pair of face materials is a transparent face material, and the transparent face material side is disposed adjacent to the resin layer. At this time, a part of the display elements are on the outermost surface side of the transparent face material on the side adjacent to the resin layer, and an optical film such as a polarizing plate or a phase difference plate is provided. In this case, the resin layer is in a state in which the optical film on the display element is bonded to the surface material.

The surface of the joint between the display element and the resin layer may be subjected to surface treatment in order to enhance the adhesion between the sealing member and the sealing portion. The surface treatment can be applied only to the peripheral portion or to the entire surface of the face material. The surface treatment method is, for example, a method which can be processed by a low-temperature processing followed by a primer or the like.

The thickness of the display element is usually 0.4 to 4 mm when it belongs to a liquid crystal display element activated by a TFT, and is usually 0.2 to 3 mm when it belongs to an EL display element.

[resin layer]

The resin layer is a layer formed by curing the curable resin composition of the present invention (hereinafter also referred to as "photocurable resin composition for resin layer formation").

The curable resin composition of the present invention (the photocurable resin composition for forming a resin layer of the present embodiment) can reduce the elastic modulus after curing and can reduce the stress generated during curing. Therefore, it is possible to suppress the adverse effect on the display performance of the display element due to the stress. Moreover, since the curable resin composition has a low viscosity when it is not cured, the supply of the curable resin composition on the surface of the face material can be performed in a short time, and thus it is easy to prevent the occurrence of air bubbles remaining after the surface material and the back surface material are laminated.

The thickness of the resin layer is preferably 0.03 to 2 mm, more preferably 0.1 to 0.8 mm, and particularly preferably 0.2 to 0.6 mm. When the thickness of the resin layer is 0.03 mm or more, the resin layer can effectively buffer the impact due to an external force from the side of the transparent surface material, and the display element can be protected. In particular, when the display element is sensitive to external force and is more likely to affect the display quality, it is preferably set to a thickness of 0.2 mm or more. Further, in the production method of the present embodiment, even if a foreign material exceeding the thickness of the resin layer is mixed between the transparent surface material and the display element, the thickness of the resin layer does not change much, and the light penetration property is less affected. . When the thickness of the resin layer is 2 mm or less, bubbles are less likely to remain in the resin layer, and the overall thickness of the display device does not become excessively thick. When the elastic modulus of the resin layer is small, it is preferably set to a thickness of 0.6 mm or less in order to suppress the displacement of the display element over time.

The method of adjusting the thickness of the resin layer is a method of adjusting the supply amount of the photocurable resin composition for forming a liquid resin layer supplied to the first face material by adjusting the thickness of the sealing portion to be described later.

[seal department]

The sealing portion is formed by applying a photocurable resin composition for forming a liquid sealing portion, which is described later, and is cured. Since the outer side region of the image display area of the display element is relatively narrow, the width of the sealing portion is preferably narrow. The width of the sealing portion is preferably 0.5 to 2 mm, more preferably 0.8 to 1.6 mm.

[Light-shielding printing department]

A light-shielding printing portion may be provided at a peripheral portion of the transparent surface material as needed. The light-shielding printing unit hides the wiring member or the like connected to the display element so that it cannot be seen from the transparent surface material side except for the image display area of the display element. The light-shielding printing portion can be provided on the joint surface of the transparent surface material and the resin layer or the back surface thereof, and is preferably provided on the joint surface of the transparent surface material and the resin layer from the viewpoint of reducing the parallax between the light-shielding printing portion and the image display region. When the transparent surface material is a glass plate, if the light-shielding printing portion is printed using a ceramic containing a black pigment, the light-shielding property is high, which is preferable. The light-shielding printing portion can also be formed by bonding a transparent film having a light-shielding portion on the front or back surface to the transparent surface material. A transparent face material without a light-shielding printing portion can also be used.

[shape]

The shape of the display device is usually rectangular.

The size of the display device is not particularly limited because the manufacturing method of the present embodiment is particularly suitable for the manufacture of a display device having a large area. Therefore, in the case of using a liquid crystal display element, it is preferably 0.3 in the case of a PC screen. m × 0.18 m is preferably 0.4 m × 0.3 m or more, and more preferably 0.7 m × 0.4 m or more in the case of a television receiver. The upper limit of the size of the display device is mostly determined according to the size of the display element. Further, an excessively large display device tends to be difficult in processing such as setting. The upper limit of the size of the display device is from the limit, and is usually about 2.5 m x 1.5 m. In the case of a small display, it is preferably 0.14 m × 0.08 m or more.

The transparent surface material to be the protective sheet and the size of the display element may be substantially equal, but in many cases, the transparent surface material is larger than the display element in a relationship with the other housing of the display device. Further, contrary to the configuration of the other housing, the transparent surface material may be made smaller than the display element.

<Method of Manufacturing Display Device>

The method of manufacturing the display device of the present embodiment includes the following steps (a) to (d).

(a) The photocuring property for forming a liquid sealing portion containing a curable compound (I) and a photopolymerization initiator (C1) on the surface peripheral portion of the first surface material (back surface material (or surface material)) The resin composition is a step of forming an uncured seal portion (however, when the first face material is a display element, a seal portion is formed on the surface on the image display side).

(b) A step of supplying a photocurable resin composition for forming a liquid resin layer containing a curable compound (II) and a photopolymerization initiator (C2) to a region surrounded by the unhardened seal portion.

(c) The second surface material (surface material (or back material)) is superposed on the resin layer-forming photocurable resin composition under a reduced pressure of 100 Pa or less to obtain a photocurable resin for resin layer formation. a step of laminating a precursor having a first surface material, a second surface material, and an unhardened sealing portion (however, when an antireflection film is provided on the surface of the second surface material, the back side is When the surface-adjacent resin layer is formed by the photocurable resin composition, the surface-side resin layer is superposed on the image-display side. .

(d) A step in which the uncured sealing portion and the resin layer-forming photocurable resin composition are subjected to light irradiation to be cured in a pressure environment of 50 kPa or more.

When the light-shielding portion is not formed on the transparent surface material, the sealing portion and the resin layer-forming photocurable resin composition are irradiated with light from the transparent surface material side of the laminated precursor through the light transmitting portion.

When the light shielding portion is formed on the peripheral portion of the transparent surface material, the area of the light transmission portion surrounded by the light shielding portion is smaller than the area of the resin layer surrounded by the sealing portion, and the resin layer is formed of a photocurable resin. The absorption wavelength region (λ2) of the photopolymerization initiator (C2) contained in the product is larger than the absorption wavelength region of the photopolymerization initiator (C1) contained in the photocurable resin composition for sealing portion formation ( Λ1) exists on the longer wavelength side, and the light irradiated from the side of the laminated precursor in the above step (d) covers the wavelength light and the absorption wavelength region (λ2) in the absorption wavelength region (λ1). Wavelength of light.

In the production method of the present embodiment, the photocurable resin composition for forming a liquid resin layer is sealed between the first surface material and the second surface material in a reduced pressure environment, and is subjected to a high pressure environment under an atmospheric pressure environment. The resin layer to be sealed is formed by a method in which a photocurable resin composition is cured to form a resin layer (decompression lamination method). The method of encapsulating the photocurable resin composition for forming a resin layer under reduced pressure is not a method of injecting a photocurable resin for forming a resin layer in a narrow space between the first surface material and the second surface material. The photocurable resin composition for forming a resin layer is supplied to the entire surface of the first surface material, and then the second surface material is superposed on the surface of the first surface material and the second surface material. A method of resin composition.

An example of a method for producing a transparent laminate by encapsulating a photocurable resin composition for forming a liquid resin layer under reduced pressure and curing the photocurable resin composition for forming a resin layer under atmospheric pressure known. For example, the method for producing a transparent laminate described in the pamphlet of International Publication No. WO 2008/81838, the pamphlet of International Publication No. 2009/16943, and the photocurable resin composition used in the production method are incorporated in the present specification.

[Step (a)]

First, an uncured seal portion is formed along the peripheral portion of the surface of the first face material. The first surface material can be used arbitrarily as a back material or a surface material.

When the first surface material is a transparent surface material which is a protective sheet for a display element, the surface on which the uncured seal portion is formed may be arbitrarily one of two surfaces. When the characteristics of the two surfaces are different, the desired surface is selected. For example, when one of the surfaces has a surface treatment for imparting an adhesion between the resin layer and the resin layer, an uncured seal portion is formed on the surface. Further, when an antireflection layer is provided on one of the surfaces, an uncured seal portion is formed on the back surface thereof.

When the first surface material is a display element, the surface of the uncured seal portion is formed as the surface on the image display side.

The uncured seal portion is characterized in that, in the step (c) described later, the photocurable resin composition for forming a liquid resin layer does not have an interface between the unhardened seal portion and the first face material, and the unhardened seal portion. The interface between the second surface material and the second surface material leaks more than the interface adhesion force and has a firmness to maintain the shape. Therefore, it is preferable that the unhardened sealing portion is formed of a photocurable resin composition for forming a sealing portion having a high viscosity, and applied by, for example, printing, dispensing, or the like.

In addition, in order to maintain the space between the first surface material and the second surface material, spacer particles having a predetermined particle diameter may be blended in the photocurable resin composition for sealing portion formation.

Immediately after the application of the photocurable resin composition for forming the sealing portion, the sealing portion is partially semi-cured by irradiating light for curing the sealing portion, and the shape of the sealing portion is maintained for a longer period of time.

[Photocurable resin composition for sealing portion formation]

The photocurable resin composition for sealing portion formation (hereinafter also referred to as "sealing material") is a liquid composition containing a photocurable curable compound (I) and a photopolymerization initiator (Cl).

The viscosity of the photocurable resin composition for forming the sealing portion is preferably 500 to 3,000 Pa s, more preferably 800 to 2,500 Pa s, and particularly preferably 1,000 to 2,000 Pa s. When the viscosity is 500 Pa ‧ or more, the shape of the unhardened seal portion can be maintained for a long period of time, and the height of the seal portion can be sufficiently maintained. If the viscosity is 3,000 Pa ‧ or less, the sealing portion can be formed by a coating method.

The viscosity of the photocurable resin composition for forming a seal portion was measured at 25 ° C using an E-type viscometer.

(hardening compound (I))

The curable compound (I) is preferably one or more types of oligomers (A) and monomers (B), in which the viscosity of the photocurable resin composition for sealing a portion is easily adjusted within the above range. In one or more types, the oligomer (A) has a curable group and has a number average molecular weight of 30,000 to 100,000; and the monomer (B) has a curable group and has a molecular weight of from 125 to 600.

The curable group of the oligomer (A) or the monomer (B) may, for example, be an addition polymerizable unsaturated group (such as a acryloxy group, a methacryloxy group, etc.), an unsaturated group and sulfur. From the viewpoint of a combination of an alcohol group and the like, a sealing portion having a high curing rate and high transparency can be obtained, and is preferably selected from the group consisting of an acryloxy group and a methacryloxy group.

The curable group in the oligomer (A) and the curable group in the monomer (B) may be the same or different from each other. Because of the hardening group in the oligomer (A) having a relatively high molecular weight, the reactivity easily becomes lower than the hardening group in the monomer (B) having a lower molecular weight, and thus the hardening of the monomer (B) is advanced. The viscous enthalpy of the composition as a whole is increased, and the hardening reaction is likely to be inhomogeneous. In order to reduce the reactivity of the hardening group, the uniformity of the sealing portion can be obtained, and it is preferable to set the hardening group in the oligomer (A) to a highly reactive propylene oxy group, and to form a monomer. The curable group in (B) is a methacryloxy group having a low reactivity.

The number average molecular weight of the oligomer (A) is from 30,000 to 100,000, preferably from 40,000 to 80,000, more preferably from 50,000 to 65,000. When the number average molecular weight of the oligomer (A) is within this range, it is easier to adjust the viscosity of the photocurable resin composition for sealing portion formation within the above range.

The number average molecular weight of the oligomer (A) is obtained by GPC measurement and is a polystyrene-equivalent number average molecular weight. Further, in the GPC measurement, when there is a spike of an unreacted low molecular weight component (monomer or the like), the peak is excluded to obtain a number average molecular weight.

The molecular weight of the monomer (B) is from 125 to 600, preferably from 140 to 400, more preferably from 150 to 350. When the molecular weight of the monomer (B) is at least 125, the volatilization of the monomer (B) can be suppressed when the display device is produced by the pressure reduction lamination method described later. When the molecular weight of the monomer (B) is 600 or less, the solubility of the monomer (B) to the high molecular weight oligomer (A) can be improved, and the viscosity of the photocurable resin composition for forming a sealing portion can be appropriately performed. Adjustment.

(oligomer (A))

The oligomer (A) is preferably one having an average of 1.8 to 4 curable groups per molecule, from the viewpoints of the curability of the photocurable resin composition for forming a sealing portion, the mechanical properties of the sealing portion, and the like.

The oligomer (A) may be a urethane-bonded urethane oligomer, a polyoxyalkylene polyol poly(meth) acrylate, or a polyester polyol. Base) acrylate and the like.

According to the molecular design of the urethane chain, etc., it is possible to widely adjust the mechanical properties of the resin after curing, and the adhesion to the surface material, and it is preferred to use a polyol and a polyisocyanate as raw materials. The urethane oligomer is more preferably a urethane oligomer (A1) described later. The polyol is preferably a polyoxyalkylene polyol.

(Amino acid ester oligomer (A1))

The urethane acrylate oligomer (A1) having a number average molecular weight in the range of 30,000 to 100,000 is difficult to be synthesized according to an ordinary method because it is highly viscous, and even if it is synthetic, it is difficult to carry out the monomer (B). )the mix of.

Therefore, it is preferred to directly use the obtained product as a seal after synthesizing the urethane oligomer (A1) according to the synthesis method using the monomer (B) (the following monomers (B1) and (B2)). The photocurable resin composition is formed, or the obtained product is further diluted with the monomer (B) (the following monomer (B1), monomer (B3), etc.) to be used as a sealing portion forming light. A curable resin composition.

‧ Monomer (B1): A monomer having a curable group and a group which does not react with an isocyanate group in the monomer (B).

‧ Monomer (B2): A monomer having a curable group and having a group reactive with an isocyanate group in the monomer (B).

‧ Monomer (B3): A monomer having a curable group and having a hydroxyl group in the monomer (B).

Synthesis method of urethane oligomer (A1):

In the presence of the monomer (B1) as a diluent, the polyol is reacted with the polyisocyanate to obtain a prepolymer having an isocyanate group, and then the monomer (B2) is subjected to the isocyanate group of the prepolymer. The method of reaction.

The polyol and the polyisocyanate are known compounds, and the polyol (i), the diisocyanate (ii), etc. which are the raw materials of the urethane-based oligomer (a) described in the pamphlet of International Publication No. 2009/016943, Both are included in this specification.

Examples of the polyhydric alcohol (i) include polyoxyalkylene polyols such as polyoxyethylene glycol and polyoxypropylene propylene glycol; polyester polyols and polycarbonate polyols. Among these, a polyoxyalkylene polyol, more preferably a polyoxypropylene propylene polyol, is preferred. Further, when the oxygen-extended propyl group of the polyoxy-extension propyl polyol is substituted with an oxygen-extended ethyl group, the compatibility of the photocurable resin composition for forming a resin layer with other components can be improved, which is preferable. .

Here, "may also replace a part of the oxygen-extended propyl group with an oxygen-extended ethyl group", which means that a part of the oxygen-extended propyl structure constituting the polyoxy-extension propyl polyol molecule is substituted with an oxygen-extended ethyl group. The molecular structure of the structure. The same descriptions as used hereinafter refer to the same meanings. The oxygen-extended ethyl structure can be present in the polyoxy-extension propylene polyol molecule in a random or block form. Further, the oxygen-extended ethyl structure may be internal to the polyoxy-extension propylene polyol molecule or just before the terminal hydroxyl group. When the oxygen-extended ethyl structure is located just before the terminal hydroxyl group, it can be obtained by adding ethylene oxide to the polyoxy-extension propyl polyol.

The diisocyanate (ii) is preferably selected from the group consisting of aliphatic diisocyanates, alicyclic diisocyanates, and diisocyanates having no yellowing aromatic diisocyanate. Among them, examples of the aliphatic polyisocyanate include hexamethylene diisocyanate, 2,2,4-trimethyl-hexamethylene diisocyanate, and 2,4,4-trimethyl-hexamethylene. Diisocyanate and the like. Examples of the alicyclic polyisocyanate include isophorone diisocyanate and methylene bis(4-cyclohexyl isocyanate). The non-yellowing aromatic diisocyanate may be, for example, a perylene diisocyanate. These may be used alone or in combination of two or more.

The monomer (B1) may, for example, be an alkyl (meth)acrylate having an alkyl group having 8 to 22 carbon atoms [such as: n-dodecyl (meth)acrylate, or n-methyl (meth)acrylate) Octaalkyl ester, n-decyl (meth) acrylate, etc., (meth) acrylate having an alicyclic hydrocarbon group [such as: (meth) acrylate Ester, adamantyl (meth)acrylate, etc.].

The monomer (B2) may, for example, be a monomer having an active hydrogen (such as a hydroxyl group, an amine group, or the like) and a curable group, and specific examples thereof include (meth)acrylic acid having a hydroxyalkyl group having 2 to 6 carbon atoms. Hydroxyalkyl esters [such as: 2-hydroxymethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, (meth)acrylic acid-4 - Hydroxybutyl ester or the like], etc., preferably a hydroxyalkyl acrylate having a hydroxyalkyl group having 2 to 4 carbon atoms.

(monomer (B))

The monomer (B) is preferably one to three hardening groups per molecule from the viewpoints of the curability of the photocurable resin composition for forming a sealing portion, the mechanical properties of the sealing portion, and the like.

The photocurable resin composition for forming a sealing portion may contain a monomer (B1) as a diluent in the method for synthesizing the urethane oligomer (A1) as the monomer (B). Further, the monomer (B) may contain the unreacted monomer (B2) used in the synthesis method of the above urethane oligomer (A1).

The monomer (B) preferably contains a monomer having a hydroxyl group (B3) from the viewpoint of the adhesion between the face material and the sealing portion and the solubility of various additives to be described later.

The monomer (B3) having a hydroxyl group is preferably, for example, a hydroxy methacrylate having a hydroxyl group of 1 to 2 and a carbon number of 3 to 8 (such as 2-hydroxypropyl methacrylate or methyl group). 2-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, -6-hydroxyhexyl methacrylate, glycerol monomethacrylate, etc., more preferably 2-hydroxybutyl methacrylate ester.

The content ratio of the monomer (B) in the photocurable resin composition for forming a seal portion is the total of the curable compound (I) (100% by mass), that is, the total of the oligomer (A) and the monomer (B) ( 100% by mass) is preferably 15 to 50% by mass, more preferably 20 to 45% by mass, still more preferably 25 to 40% by mass. When the ratio of the monomer (B) is 15% by mass or more, the curability of the photocurable resin composition for forming a seal portion and the adhesion between the face material and the sealing portion are good. When the ratio of the monomer (B) is 50% by mass or less, the viscosity of the photocurable resin composition for sealing portion formation can be easily adjusted to 500 Pa ‧ or more.

Further, in the synthesis of the urethane acrylate oligomer (A1), the monomer (B2) which reacts with the isocyanate group of the prepolymer is present in the form of a part of the oligomer (A), It is not included in the content of the monomer (B) in the photocurable resin composition for sealing portion formation. On the other hand, in the synthesis of the urethane oligomer (A1), the monomer (B1) used as a diluent and the monomer added after the synthesis of the urethane oligomer (A1) (B) The content of the monomer (B) in the photocurable resin composition for forming a seal portion is included.

(Photopolymerization initiator (C1))

The photopolymerization initiator (C1) contained in the photocurable resin composition for forming a sealing portion may, for example, be an acetophenone type, a ketal type, a benzoin or a benzoin ether type, or a phosphine oxide. A photopolymerization initiator such as a diphenylketone, a thioxanthone or an anthraquinone is preferably a photopolymerization initiator such as an acetophenone-based, ketal-based or benzoin-ether. When curing with a short-wavelength visible light, a phosphine oxide-based photopolymerization initiator is preferred from the viewpoint of absorbing a wavelength region. By using two or more kinds of photopolymerization initiators (C1) having different absorption wavelength regions in combination, the curing time can be further accelerated or the surface hardenability of the sealing portion can be improved. In addition, a light-shielding printing portion is provided on the transparent surface material, and the uncured sealing portion held by the light-shielding printing portion and the photocurable resin composition for forming a resin layer are irradiated with light from the side surface of the surface material. In the case of hardening, it is possible to use a photopolymerization initiator (C2) which will be described later in the range of curing of the resin layer-forming photocurable resin composition which does not inhibit the adjacent portion of the uncured seal portion. When there is a combination, the ratio of the polymerization initiator (C1) to the polymerization initiator (C2) is excellent in efficiency and effective in hardening, and based on the mass ratio of (C1):(C2), Good for 50:1~5:1. In order to form the photocurable resin composition for the resin layer held by the light-shielding printing portion, the light which is irradiated from the side surface of the surface material can be cured in a short time by the uncured sealing material, and the photocurable resin for sealing portion formation can be formed. The composition preferably does not contain a photopolymerization initiator (C2).

The content of the photopolymerization initiator (C1) in the photocurable resin composition for forming a sealing portion (in the case where the photopolymerization initiator (C2) is contained, the total amount of (C1) and (C2)) is The total amount of the oligomer (A) and the monomer (B) is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the total of the curable compound (I).

(additive)

The photocurable resin composition for forming a sealing portion may contain, for example, a polymerization terminator, a photocuring accelerator, a chain transfer agent, a light stabilizer (such as an ultraviolet absorber, a radical scavenger, etc.), and an anti-resistance. Various additives such as an oxidizing agent, a flame retardant, an adhesion promoter (such as a decane coupling agent), a pigment, and a dye preferably contain a polymerization terminator and a photostabilizer. In particular, when the amount of the polymerization terminator is less than the polymerization initiator, the stability of the photocurable resin composition for forming a seal portion can be improved, and the molecular weight of the resin layer after curing can be adjusted. When the sealing material is hardened by light irradiated from the side surface of the face material, such as a polymerization terminator, a chain transfer agent, a light stabilizer, a pigment, a dye, etc., which have an effect of delaying the hardening reaction, it is preferable not to use as much as possible. Or reduce the content.

The polymerization terminator may, for example, be a hydroquinone (such as 2,5-di-t-butylhydroquinone, etc.), a catechol-based (such as p-tert-butylcatechol), an anthraquinone, or a phenolthiophene. A polymerization terminator such as a hydroxytoluene system.

The photosensitizer may, for example, be a UV absorber (such as a benzotriazole system, a diphenylketone system or a salicylate system), a radical scavenger (such as a hindered amine system), or the like.

The antioxidant is, for example, a phosphorus-based or sulfur-based compound.

The total amount of the additives is 100 parts by mass, preferably 10 parts by mass or less, more preferably 5 parts by mass or less, based on 100 parts by mass of the total of the curable compound (I), that is, the oligomer (A) and the monomer (B). .

[Step (b)]

After the step (a), a liquid curable resin composition for forming a liquid resin layer is supplied to a region surrounded by the unhardened sealing portion.

The supply amount of the resin layer-forming photocurable resin composition is set so that the space formed by the sealing portion, the first surface material, and the second surface material is filled with the photocurable resin composition for forming a resin layer, and The first surface material and the second surface material are separated by a predetermined interval (that is, the resin layer is set to a predetermined thickness). In this case, it is preferable to consider the volume reduction due to the hardening shrinkage of the photocurable resin composition for forming a resin layer in advance. Therefore, the amount is preferably a thickness of the photocurable resin composition for forming a resin layer, and a certain amount is thicker than a predetermined thickness of the resin layer. When the hardening shrinkage is small, the predetermined thickness of the resin layer and the thickness of the resin layer-forming photocurable resin composition may be made substantially equal.

The supply method is a method in which the first surface material is laid flat and supplied in a dot shape, a line shape or a surface shape by means of a supply means such as a dispenser or a die coater.

[Photocurable resin composition for resin layer formation]

In the photocurable resin composition for forming a resin layer, when the dynamic viscoelasticity after curing is measured, a liquid having a shear elastic modulus of 5 × 10 ² to 1 × 10 ⁵ Pa and a loss tangent (tan δ) of 1.4 or less is stored. A photocurable resin composition.

The measurement method of the storage shear modulus and the loss tangent is as described in detail later, and the dynamic shear stress is applied to the photocurable resin composition for forming an uncured resin layer by using a dynamic viscoelasticity measuring device. A method of irradiating light to harden a resin composition.

When the shear modulus after hardening is 5 × 10 ⁵ Pa or less, the stress generated by shrinkage of the resin during curing can be sufficiently reduced, and the influence on the display quality of the display panel can be suppressed. If the shear elastic modulus is 5 × 10 ² Pa or more, the elastic deformation of the resin layer is less likely to occur, and the positional displacement of the display element and the transparent face material can be easily prevented. Further, if the loss tangent is 1.4 or less, even if the display device is used vertically, the display element can be sufficiently fixed to the transparent face material, and the resin layer can be prevented from being plastically deformed due to the own weight of the display element. The time when the display component is shifted in position is present.

The storage shear modulus is preferably 8 × 10 ² to 5 × 10 ⁴ Pa, more preferably 1 × 10 ³ to 3 × 10 ⁴ Pa. Further, the loss tangent is preferably 1.0 or less, more preferably 0.5 or less.

In the case of a display element which is likely to affect the display performance due to stress generated by shrinkage during curing of the resin layer, the IPS type liquid crystal display element described later preferably has a storage shear elastic modulus of 5 × 10 ² after hardening. A liquid photocurable resin composition of ~5 × 10 ³ Pa and loss tangent (tan δ) of less than 0.2. By setting the shear modulus to 5 × 10 ³ Pa or less, the stress due to shrinkage of the resin during hardening can be sufficiently suppressed to be less than a small value, and the loss tangent (tan δ) is less than 0.2, even if It is a resin layer having a low shear modulus, and the plastic deformation of the resin layer due to the self-weight of the display element can be suppressed. In this case, the loss tangent (tan δ) is preferably 0.1 or less.

The lower limit of the loss tangent is not particularly limited, and can be set in a range that can be achieved in production. When it is a soft resin layer, it is usually 0.01 or more.

The viscosity of the photocurable resin composition for forming a resin layer is preferably 0.05 to 50 Pa s, more preferably 1 to 20 Pa s. When the viscosity is 0.05 Pa s or more, the ratio of the monomer (B') described later can be suppressed, and the deterioration of the physical properties of the resin layer can be suppressed. Moreover, since the low boiling point component is small, it is suitable for the pressure reduction lamination method mentioned later. If the viscosity is 50 Pa ‧ or less, the resin layer is less likely to have bubbles remaining.

The viscosity of the photocurable resin composition for forming a resin layer was measured at 25 ° C using an E-type viscometer.

The photocurable resin composition for forming a resin layer is preferably a liquid composition and contains a photocurable curable compound (II), a photopolymerization initiator (C2), and a non-curable oligomer (D). . When the non-curable oligomer (D) is cured by the photocurable resin composition for forming a resin layer, it does not undergo a curing reaction with the curable compound (II) in the composition, and contains 0.8~ per molecule. 3 hydroxyl oligomers.

When the photocurable resin composition for forming a resin layer contains the non-curable oligomer (D), the storage shear elastic modulus can be lowered while suppressing an increase in the loss of tangent (tan δ) of the resin layer after curing. Therefore, the respective preferred ranges of the storage shear elastic modulus and the loss tangent (tan δ) in the dynamic viscoelasticity measurement can be simultaneously achieved.

Further, by a small amount of a chain transfer agent, the molecular weight of the resin layer after curing can be adjusted to lower the storage elastic modulus of the resin layer, but in many cases, the curing rate is slowed down.

In the photocurable resin composition for forming a resin layer containing a large amount of the non-curable oligomer (D) of the present invention, since the elastic modulus can be adjusted by the content of the oligomer (D), it is preferred to reduce chain transfer. The content of the agent, or not. Specifically, the amount of the chain transfer agent added is preferably 1 part by mass or less, based on 100 parts by mass of the total of the curable compound (II), that is, the total of the oligomer (A') and the monomer (B'). The quality is less than 0.5 parts by mass. The chain transfer agent can be, for example, n-dodecyl mercaptan.

(hardening compound (II))

The curable compound (II) in the photocurable resin composition for forming a resin layer is one or more types of curable compounds which undergo a curing reaction when the photocurable resin composition for forming a resin layer is cured. At least one of the curable compounds is preferably a compound (IIa) which does not cause a reaction hydroxyl group when the photocurable resin composition for forming a resin layer is cured.

When the curable compound (II) contains the compound (IIa), a hydroxyl group is present in the cured product in which the curable compound (II) is hardened alone. The presence of the hydroxyl group contributes to the stabilization of the non-curable oligomer in the photocurable resin composition for forming a resin layer.

Therefore, the compound (IIa) having the hydroxyl group which does not react at the time of hardening may be any unreacted hydroxyl group after the hardening reaction, for example, even if a part of the hydroxyl group of the compound (IIa) is hardened, the other part is not hardened. The reaction can be carried out in an unreacted state.

The compound (IIa) having a hydroxyl group which does not react during curing may be a monomer or a oligomer having a repeating unit as long as it has a curable group which contributes to the curing reaction and has a hydroxyl group. . From the viewpoint of easily adjusting the viscosity of the photocurable composition at the time of curing, it is preferred to use a monomer having a curable group and having a hydroxyl group as the compound (IIa). Specific examples of the compound (IIa) which is a monomer having a hydroxyl group are preferably a (meth)acrylic acid hydroxyester having a hydroxyl group of 1 to 2 and a carbon number of 3 to 8 [such as (meth)acrylic acid] -2-hydroxypropyl ester, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, glycerol mono (methyl) Acrylate, etc., more preferably 2-hydroxybutyl methacrylate.

In view of the fact that the curable compound (II) is more preferably adjusted to have a viscosity within the above range, it is preferred to contain one or more kinds of the oligomer (A') and one or more monomers (B'). (A') has a curable group and has a number average molecular weight of 1,000 to 100,000. The monomer (B') has a curable group and has a molecular weight of from 125 to 600.

In this case, it is preferred that at least a part of the monomer (B') is a monomer (B3) having a curable group and having a hydroxyl group and having a molecular weight of from 125 to 600.

The curable group in the oligomer (A') or the monomer (B') may, for example, be an addition polymerizable unsaturated group (such as a acryloxy group, a methacryloxy group, etc.), or an unsaturated group. From the viewpoint of a combination of a thiol group and the like, a resin layer having a high curing rate and high transparency can be obtained, and is preferably selected from the group consisting of a propylene oxy group and a methacryloxy group.

The curable group in the oligomer (A') and the curable group in the monomer (B') may be the same or different from each other. Because of the hardening group of the higher molecular weight oligomer (A'), the reactivity is more likely to become lower than the hardening group in the lower molecular weight monomer (B'), and thus the monomer (B') is hardened. It will be carried out first, resulting in an increase in the viscosity of the composition as a whole, which may cause the hardening reaction to be inhomogeneous. In order to reduce the reactivity of the curable groups, the homogeneous resin layer may be obtained, and the sulfomethoxy group in the oligomer (A') is preferably a highly reactive propylene oxime group, and The curable group in the body (B') is a methacryloxy group having a low reactivity.

(oligomer (A'))

The number average molecular weight of the oligomer (A') is preferably from 1,000 to 100,000, more preferably from 10,000 to 70,000. When the number average molecular weight of the oligomer (A') is within this range, the viscosity of the resin layer-forming photocurable resin composition is easily adjusted within the above range.

The number average molecular weight of the oligomer (A') is a polystyrene-converted number average molecular weight obtained by GPC measurement. Further, in the GPC measurement, when a spike of unreacted low molecular weight component (monomer or the like) occurs, the peak is excluded to obtain a number average molecular weight.

The oligomer (A') is preferably one having an average of 1.8 to 4 curable groups per molecule, from the viewpoints of the curability of the photocurable resin composition for forming a resin layer, the mechanical properties of the resin layer, and the like.

The oligomer (A') may, for example, be a urethane-bonded urethane oligomer, a polyoxyalkylene polyol poly(meth)acrylate, or a polyester polyol. (Meth) acrylate or the like can be broadly adjusted from the viewpoint of molecular design of the urethane chain, etc., and the mechanical properties of the resin after curing and the adhesion to the surface material can be widely adjusted, and urethane oligomerization is preferred. (A2).

The urethane oligomer (A2) is preferably obtained by reacting a polyol with a polyisocyanate to obtain a prepolymer having an isocyanate group, and then reacting the isocyanate group of the prepolymer with the monomer (B2). The method of reaction is synthesized.

The polyol and the polyisocyanate are known compounds, and the polyol (i), the diisocyanate (ii), etc. which are the raw materials of the urethane-based oligomer (a) described in the pamphlet of International Publication No. 2009/016943, Both are included in this specification.

A commercially available product may be used as the urethane oligomer (A2), for example, EB230 (manufactured by DAICEL-CYTEC Co., Ltd., which is a reaction product of 2, polypropylene glycol/IPDI/-2-hydroxyethyl acrylate) U-200A X (manufactured by Shin-Nakamura Chemical Co., Ltd., is a reaction product of a functional group number 2, an aliphatic polyester polyol/aliphatic or an alicyclic polyisocyanate/-2-hydroxyethyl acrylate).

The content ratio of the oligomer (A') is preferably in the total (100% by mass) of the curable compound (II), that is, the total amount (100% by mass) of the oligomer (A') and the monomer (B'). It is 20 to 90% by mass, more preferably 30 to 80% by mass. When the proportion of the oligomer (A') is 20% by mass or more, the heat resistance of the resin layer is good. When the ratio of the oligomer (A') is 90% by mass or less, the curability of the photocurable resin composition for forming a resin layer and the adhesion between the surface material and the resin layer are good. Since the molecular weight of the oligomer (A')-based curable group is large, the shrinkage at the time of curing is particularly suppressed, and the ratio of the oligomer (A') is preferably 70 to 90. %.

(monomer (B'))

The molecular weight of the monomer (B') is preferably from 125 to 600, more preferably from 140 to 400. When the molecular weight of the monomer (B') is 125 or more, when the display device is produced in accordance with the pressure reduction lamination method described later, the monomer volatilization can be suppressed. When the molecular weight of the monomer (B') is 600 or less, the adhesion between the face material and the resin layer is good.

The monomer (B') is preferably one to three hardening groups per molecule from the viewpoints of the curability of the photocurable resin composition for forming a resin layer, the mechanical properties of the resin layer, and the like.

The content ratio of the monomer (B') is preferably 10 in the total (100% by mass) of the curable compound (II), that is, the total amount (100% by mass) of the oligomer (A') and the monomer (B'). ~80% by mass, more preferably 20 to 70% by mass.

The monomer (B') preferably contains a monomer (B3) having a sclerosing group and having a hydroxyl group. The monomer (B3) contributes to the stabilization of the non-curable oligomer (D). Further, when the monomer (B3) is contained, good adhesion between the face material and the resin layer can be easily obtained. The number of hydroxyl groups in one molecule of the monomer (B3) can be arbitrarily selected so that the non-curable oligomer (D) can be stabilized. However, from the viewpoint of easiness, it is preferred to have 1 in one molecule. ~2.

The monomer (B3) having a hydroxyl group is, for example, the same as the monomer (B3) in the photocurable resin composition for forming a sealing portion, and is preferably 2-hydroxybutyl methacrylate.

The content ratio of the monomer (B3) is preferably 10% in the total (100% by mass) of the curable compound (II), that is, the total amount (100% by mass) of the oligomer (A') and the monomer (B'). 60% by mass, more preferably 20 to 50% by mass. When the content ratio of the monomer (B3) is 10% by mass or more, the effect of improving the stability of the photocurable resin composition for forming a resin layer and improving the adhesion between the surface material and the resin layer can be easily obtained. When the content ratio of the monomer (B3) is 60% by mass or less, the hardness of the cured product composed of the photocurable resin composition for forming a resin layer is not excessively high, which is preferable.

The monomer (B') preferably contains the following monomer (B4) from the viewpoint of mechanical properties of the resin layer. Since the monomer (B4) lowers the glass transition temperature (Tg) of the resin layer after hardening, it contributes to a decrease in the elastic modulus of the resin layer after hardening, and the flexibility of the resin layer can be improved.

However, when the curability of the photocurable resin composition for forming a resin layer is increased and the time required for curing is shortened, the content of the monomer (B4) may be preferably reduced or may not be contained.

Monomer (B4): one or more selected from the group consisting of alkyl methacrylates having an alkyl group having 8 to 22 carbon atoms. When the carbon number is 8 or more, the glass transition temperature of the cured product can be lowered, which is preferable. When the carbon number is 22 or less, it is preferred that the raw material alcohol can be easily obtained through natural materials.

Examples of the monomer (B4) include n-dodecyl methacrylate, n-octadecyl methacrylate, n-decyl methacrylate, and the like. An alkyl ester, or n-octadecyl methacrylate.

The content ratio of the monomer (B4) is preferably 5% in the total (100% by mass) of the curable compound (II), that is, the total amount (100% by mass) of the oligomer (A') and the monomer (B'). 50% by mass, more preferably 15 to 40% by mass. When the content ratio of the monomer (B4) is 5% by mass or more, the sufficient addition effect of the monomer (B4) can be easily obtained.

(Photopolymerization initiator (C2))

The photopolymerization initiator (C2) contained in the photocurable resin composition for forming a resin layer may, for example, be an acetophenone type, a ketal type, a benzoin or a benzoin ether type, or a phosphine oxide. A photopolymerization initiator such as a diphenyl ketone, a thioxanthone or an anthraquinone, preferably a phosphine oxide-based or thioxanthone-based photopolymerization initiator, which suppresses coloration after photopolymerization More preferably, it is a phosphine oxide system.

The content of the photopolymerization initiator (C2) of the photocurable resin composition for forming a resin layer is 100% of the total of the curable compound (II), that is, the total of the oligomer (A') and the monomer (B'). The mass part is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass.

When a part of the photocurable resin composition for forming a resin layer adjacent to the sealing material is hardened by light irradiated from the side of the surface material, the photopolymerization initiator (C2) preferably has an absorption wavelength region ( Λ2) exists on the longer wavelength side than the absorption wavelength region (λ1) of the photopolymerization initiator (C1). The photopolymerization initiator (C2) may have only an absorption wavelength region (λ2), and may have an absorption wavelength region (λ1') and an absorption wavelength region (λ2) which are repeated with the absorption wavelength region (λ1).

(non-hardening oligomer (D))

The non-curable oligomer (D) is excellent in compatibility with the photocurable resin composition for forming a resin layer and contributes to hardening, so that the effect can be reduced without impairing transparency and homogeneity. Stress generated by shrinkage when the resin layer is hardened.

When the non-curable oligomer (D) is cured by the photocurable resin composition for forming a resin layer, it does not undergo a curing reaction with the curable compound (II) in the composition, and has 0.8 to 3 per molecule. Hydroxyl oligomers. Preferably, the number of hydroxyl groups per molecule is 2 to 3. When the number of hydroxyl groups per molecule is 0.8 or more, the interaction between the non-curable oligomers, or between the non-curable oligomers and the hardened material obtained from the curable compound (II), can be utilized. In view of the fact that the non-curable oligomer is stably held, the non-curable oligomer can be used in the photocurable resin composition for forming a resin layer. From the standpoint of good compatibility, it is preferred.

The number average molecular weight (Mn) of the average of one hydroxyl group of the non-curable oligomer (D) is preferably from 400 to 8,000. When the number average molecular weight of the average number of hydroxyl groups is 400 or more, the polarity of the non-curable oligomer (D) does not become too high, and the curability in the photocurable resin composition for forming a resin layer can be easily obtained. Good compatibility between the compounds (II). When the number average molecular weight of one hydroxyl group is 8000 or less, the interaction between the hydroxyl group derived from the curable compound (II) and the hydroxyl group of the non-curable oligomer (D) can be easily obtained after hardening. The non-curable oligomer (D) has an effect of stabilizing the resin layer. The interaction is speculated to involve hydrogen bonding.

The non-curable oligomer (D) may be used alone or in combination of two or more.

Examples of the hydroxyl group-containing non-curable oligomer (D) include a high molecular weight polyol, and the like, and a polyoxyalkylene polyol, a polyester polyol, and a polycarbonate polyol are preferable.

The polyoxyalkylene polyol may, for example, be a polyoxyalkylene monool having a carbon number of 2 to 4 oxygen alkyl repeating units, a polyoxyalkylene glycol or a polyoxyalkylene triol. Specific examples thereof include polyoxyethylene glycol, polyoxypropylene diol (hereinafter also referred to as "polypropylene glycol"), polyoxypropylene propylene glycol, and polyoxytetramethylene glycol.

The number average molecular weight (Mn) of the average hydroxyl group of the polyoxyalkylene polyol is preferably from 400 to 8,000, more preferably from 600 to 5,000.

The polyester polyol may, for example, have an aliphatic diol residue such as ethylene glycol, propylene glycol or 1,4-butanediol, and an aliphatic second such as glutaric acid, adipic acid or sebacic acid. An aliphatic polyester diol having a carboxylic acid residue.

The polycarbonate polyol may, for example, be an aliphatic polycarbonate diol having a diol residue such as 1,6-hexanediol or an aliphatic polycarbonate such as a ring-opening polymer of an aliphatic cyclic carbonate. Glycol.

The number average molecular weight (Mn) of the average hydroxyl group of the polyester polyol or the polycarbonate polyol is preferably from 400 to 8,000, more preferably from 800 to 6,000.

In the present specification, the number average molecular weight of the non-curable oligomer (D) is a hydroxyl value A (KOH mg/g) measured according to JIS K1557-1 (2007 edition), and a non-hardening oligomer (D). The number of hydroxyl groups B in one molecule is calculated according to the following formula (1).

Molecular weight of non-hardening oligomer (D) = 56.1 × B × 1000 / A ... (1)

In view of the fact that the elastic modulus of the resin layer after hardening is likely to be lower, the non-curable oligomer (D) is preferably a polyoxyalkylene polyol, more preferably a polyoxypropylene propylene polyol. Further, as described later, in order to adjust the polarity of the non-curable oligomer (D), a part of the oxygen-extended propyl group of the polyoxy-extension propylene polyol may be substituted with an oxygen-extended ethyl group. A part of the oxygen-extended propyl group may also be substituted with an oxygen-extended ethyl group, which is the same as described in the above polyol (i).

For example, from the viewpoint of compatibility, the oligomer (A') is preferably a urethane oligomer synthesized by using a polyoxyalkylene polyol and a polyisocyanate as a raw material, instead of a curable oligomer. (D) is a polyoxyalkylene polyol.

In the present invention, in order to stabilize the photocurable resin composition for forming a resin layer when it is not cured, the anti-curable oligomer (D) is inhibited from being separated from the cured resin layer, and an oligomer is preferably used. A') A molecular chain having the same structure or a similar structure as the non-hardening oligomer (D).

Specifically, in the case of forming the oligomer (A') in the photocurable resin composition of the synthetic resin layer, it is preferred to use a compound having a hydroxyl group such as a polyhydric alcohol (hereinafter also referred to as "hydroxyl-containing compound"). And the same hydroxyl group-containing compound is used as the non-curable oligomer (D).

For example, when the oligomer (A') is a urethane oligomer synthesized using a polyoxyalkylene polyol and a polyisocyanate as a raw material, it is preferred to use the polyoxyalkylene polyol as Non-hardening oligomer (D).

Alternatively, when the hydroxyl group-containing compound used as the raw material of the oligomer (A') and the hydroxyl group-containing compound used as the non-hardenable oligomer (D) are not the same, it is preferred that the molecular chains of the two have a common The repeating unit or the like has a common structure and has the same polarity as the two. The method of adjusting the polarity is, for example, a method of increasing the polarity by introducing a polar group, a method of increasing the polarity by substituting a part of the oxygen-extended propyl group with an oxygen-extended ethyl group, and reducing the molecular weight of an average of one hydroxyl group. Ways to increase polarity, etc. These methods can also be used in combination.

For example, the oligomer (A') is a polyformate propylene polyol (a') substituted with an oxygen-extended ethyl group and a polyisocyanate, and a urethane oligosaccharide synthesized as a raw material. In the case of a non-curable oligomer (D), a polyoxypropylene propylene polyol having no oxygen-extended ethyl group is preferably used, and an average molecular weight of one hydroxyl group is smaller than that of the aforementioned polyol (a'). Oxygen extended propyl polyol.

An example of the photocurable resin composition for forming an optimum resin layer is a composition of the following oligomer (A'), non-curable oligomer (D), and monomer (B'). The polymer (A') is obtained by reacting a polyoxypropyl propylene glycol partially substituted with an oxygen-extended ethyl group with an oxygen-extended ethyl group to obtain a prepolymer having an isocyanate group, and the foregoing The urethane oligomer (A2) obtained by the reaction of the body (B2); the non-hardening oligomer (D) is the same as the raw material of the urethane oligomer (A2), and the oxygen is extended to C A polyoxyalkylene propylene glycol in which a part of the base has been substituted with an oxygen-extended ethyl group; and the monomer (B') is a monomer (B3) having a hydroxyl group.

According to this, if the oligomer (A') partially has the same molecular structure as the non-curable oligomer (D), the compatibility of the non-hardening oligomer (D) in the composition can be further improved. Further, by the hydroxyl group of the monomer (B'), the interaction between the hydroxyl group in the molecular structure after curing of the curable compound (II) and the hydroxyl group in the molecular structure of the non-curable oligomer (D) is determined. The non-hardening oligomer (D) can be stably present in the cured product.

Further, in other examples, the composition of the oligomer (A'), the non-curable oligomer (D), and the monomer (B') may be obtained, and a non-hardening oligo in the composition may be obtained. The polymer (D) is in good compatibility, and the non-hardening oligomer (D) can be stably present in the cured product. The oligomer (A') is obtained by reacting a polyoxypropyl propylene glycol having a part of an oxygen-extended propyl group with an oxygen-extended ethyl group, and reacting with a polyisocyanate compound to obtain a prepolymer having an isocyanate group. a urethane oligomer (A2) obtained by reacting with the aforementioned monomer (B2); the non-curable oligomer (D) is a polyoxypropylene propylene glycol which is not substituted with an oxygen-extended ethyl group And a polyoxypropyl propylene glycol having a molecular weight smaller than a raw material of the urethane acrylate oligomer (A2); and the monomer (B') is a monomer (B3) having a hydroxyl group.

The content of the non-curable oligomer (D) in the photocurable resin composition for forming a resin layer is preferably from 10 to 90% by mass. When the content of the non-curable oligomer is 10% by mass or more, the effect of reducing the stress generated by the shrinkage of the resin during curing can be easily sufficiently obtained. If it is 90% by mass or less, the face materials can be easily fixed to each other sufficiently, and the temporal positional displacement of the surface material and the backing material can be easily and satisfactorily prevented. The content of the non-curable oligomer (D) is preferably a state in which the composition of the curable compound (II) is blended, and the like, and a state in which a storage shear elastic modulus and a loss tangent are preferable. A more preferable range is 30 to 80% by mass.

(additive)

The photocurable resin composition for forming a resin layer may contain, for example, a polymerization terminator, a photohardening accelerator, a chain transfer agent, a light stabilizer (such as an ultraviolet absorber, a radical scavenger, etc.), and an antioxidant. Various additives such as a flame retardant, an adhesion promoter (such as a decane coupling agent), a pigment, and a dye preferably contain a polymerization terminator or a light stabilizer. In particular, by containing a small amount of a polymerization terminator than the polymerization initiator, the stability of the photocurable resin composition for forming a resin layer can be improved, and the molecular weight of the resin layer after curing can be adjusted.

[Step (c)]

After the step (b), the first surface material to which the photocurable resin composition for forming a resin layer is supplied is placed in a decompression device, and is fixed on a fixed support disk in the decompression device. The first face material is placed flat on the face up of the composition.

A moving support mechanism that can move in the vertical direction is provided in an upper portion of the pressure reducing device, and a second surface material is attached to the moving support mechanism. When the second face material is the display element, the surface on the side where the image is displayed faces downward. When the antireflection layer is provided on the surface of the second face material, the surface on the side where the antireflection layer is not formed faces downward.

The second surface material is placed above the first surface material and is not in contact with the photocurable resin composition for forming a resin layer. In other words, the photocurable resin composition for forming a resin layer on the first surface material is opposed to the second surface material without coming into contact with each other.

Further, a movable support mechanism movable in the vertical direction may be provided in a lower portion of the decompression device, and a first face material to which the curable resin composition is supplied may be placed on the movement support mechanism. In this case, the second face material is attached to the fixed support disk provided on the upper portion of the pressure reducing device, and the first face material and the second face material are opposed to each other.

Further, both the first face material and the second face material may be supported by the upper and lower movement support mechanisms provided in the pressure reducing device.

After the first face material and the second face material are placed at a predetermined position, the inside of the decompression device is depressurized to form a predetermined reduced pressure environment. If possible, the first face material and the second face material may be placed at a predetermined position in the decompression device during the decompression operation or after the predetermined decompression environment is formed.

After the inside of the decompression device is a predetermined decompression environment, the second surface material supported by the moving support mechanism is moved downward, and the second surface material is superposed on the first surface material to form a photocurable layer for resin layer formation. Above the resin composition.

By superimposing, the surface of the first face material (the surface on the side where the display element is displayed on the display side) and the surface of the second face material (in the case of the display element, the side of the image display side) The photocurable resin composition for forming a resin layer is sealed in the space surrounded by the surface and the unhardened sealing portion.

When the overlap is performed, the resin composition forming photocurable resin composition is pushed and expanded by the self-weight of the second face material, the pressing from the moving support mechanism, and the like, and the space is filled with the resin layer forming light. The curable resin composition is then, when exposed to a high pressure environment in the step (d), a layer of a photocurable resin composition for forming a resin layer having little or no bubbles is formed.

The pressure reduction environment at the time of superposition is 100 Pa or less, preferably 10 Pa or more. If the reduced pressure environment is too low pressure, the components contained in the photocurable resin composition for forming a resin layer (such as a curable compound, a photopolymerization initiator, a polymerization terminator, a light stabilizer, etc.) may be caused. The possibility of adverse effects. For example, if the decompression environment is too low pressure, each component may be vaporized, and it takes time to provide a reduced pressure environment. The pressure in the reduced pressure environment is preferably 15 to 40 Pa.

The time from the time when the first surface material and the second surface material are overlapped with each other is not particularly limited, and the resin layer forming photocurable resin composition can be sealed immediately after being sealed. In the environment, after the resin layer forming photocurable resin composition is sealed, the reduced pressure state can be maintained for a predetermined period of time. By maintaining the reduced pressure state for a predetermined period of time, the resin layer forming photocurable resin composition flows in the sealed space, and the interval between the first face material and the second face material is uniform, even if the environmental pressure is raised. It is easy to maintain a sealed state. The time for maintaining the reduced pressure state may be a long time of several hours or more, and from the viewpoint of production efficiency, it is preferably within 1 hour, more preferably within 10 minutes.

In the production method of the present embodiment, when a photocurable resin composition for forming a sealing portion having a high viscosity is applied to form an uncured sealing portion, the resin layer of the laminated precursor obtained in the step (c) can be formed. The thickness of the photocurable resin composition is set to a relatively thick state of 10 μm to 3 mm.

[Step (d)]

In the step (c), after the decompression environment is released, the laminated precursor is placed in a pressure environment having an ambient pressure of 50 kPa or more.

When the laminated precursor is placed in a pressure environment of 50 kPa or more, the first face material and the second face material are conveniently pressed in a direction in which they are in close contact with each other, so that there is a closed space in the laminated precursor body. In the presence of the air bubbles, the resin layer-forming photocurable resin composition flows into the cells, and the entire sealed space is uniformly filled with the resin layer-forming photocurable resin composition.

The pressure environment is usually 80 kPa to 120 kPa. The pressure environment can be an atmospheric pressure environment or a pressure higher than this. The operation of hardening or the like of the photocurable resin composition for forming a resin layer can be carried out without requiring special equipment, and is preferably an atmospheric pressure environment.

The time from when the laminated precursor is placed in a pressure environment of 50 kPa or more, and the time until the resin layer forming photocurable resin composition starts to harden (hereinafter referred to as "high pressure holding time") is not particularly limited. When the laminated precursor is taken out from the decompression device and moved to the hardening device until the process of starting the hardening is performed under an atmospheric pressure environment, the time required for the process becomes the high pressure holding time. Therefore, when it is placed in an atmospheric pressure environment, there is no bubble in the sealed space of the laminated precursor, or the bubble disappears during the process, and the resin layer can be immediately formed with photocurability. The resin composition is hardened. When it takes time until the bubble disappears, the laminated precursor is maintained in a pressure environment of 50 kPa or more until the bubble disappears. Moreover, even if the high-pressure holding time is prolonged, it usually does not constitute an obstacle, so that the high-pressure holding time can be prolonged in view of other necessity in the process. The high-pressure holding time may be a long time of one day or more, but from the viewpoint of production efficiency, it is preferably within 6 hours, more preferably within 1 hour, and it is particularly preferably within 10 minutes from the viewpoint of improving production efficiency.

Then, by placing the laminated precursor in a pressure environment of 50 kPa or more, the resin layer forming photocurable resin composition is cured to form a resin layer capable of bonding the display element and the protective sheet. A display device can be produced.

The photocurable resin composition for forming a resin layer and the photocurable resin composition for forming a sealing portion are cured by irradiation with light. For example, a light source (such as an ultraviolet lamp, a high pressure mercury lamp, a black lamp, a chemical lamp, a UV-LED, or the like) is irradiated with ultraviolet rays or short-wavelength visible light to harden the photocurable resin composition.

In this case, the uncured seal portion formed of the photocurable resin composition for forming the sealing portion can be cured simultaneously with the curing of the photocurable resin composition for forming the resin layer, or can be formed in the resin layer. The hardening resin composition is pre-hardened before being hardened. In addition, when a part of the transparent surface material is formed with a light-shielding printing portion and is held by the light-shielding printing portion to form a sealing portion, the use of the transparent surface material is performed when the resin layer forming photocurable resin composition is cured. Since the light in the light transmitting portion is difficult to harden the sealing portion, the sealing portion can be cured only after the resin layer forming photocurable resin composition is cured.

For example, from the side of the first surface material and the second surface material of the laminated precursor having light permeability, the photocurable resin composition for forming a resin layer is irradiated with light, and from the side of the laminated precursor, The uncured seal portion and the resin layer-forming photocurable resin composition which are sandwiched between the light-shielding portion and the display element are irradiated with light.

In the first surface material and the second surface material, since the display element does not have light transmittance in a state where it is not activated, light irradiation is performed through the light transmitting portion from the side of the transparent surface material serving as the protective plate.

In addition, when the light-shielding printing portion is provided in the peripheral portion of the transparent surface material, and the uncured sealing portion or the photocurable resin composition for forming the resin layer is present in the region where the light-shielding printing portion and the display element are held, only The light from the light transmitting portion of the transparent face material is not sufficiently hardened. Therefore, light irradiation is performed from the side of the display element.

The light is preferably ultraviolet light or visible light of 450 nm or less. In particular, when an antireflection layer is provided on the transparent surface material, and the antireflection layer or the transparent resin film on which the antireflection layer has been formed, or an ultraviolet ray such as an adhesive layer between the antireflection film and the transparent surface material is not penetrated. In this case, it is necessary to use visible light for hardening.

A light source used for light irradiation from the side may be a light source used when light is irradiated from the side of the transparent surface material, but it is preferable from the viewpoint of the arrangement space of the light source and the efficient light irradiation applied to a specific place. An LED that emits ultraviolet light or emits visible light of 450 nm or less.

The step of irradiating light may be performed by irradiating light from the side of the transparent surface material, and then irradiating light from the side, or vice versa, or simultaneously performing light irradiation, so as to further promote the uncured seal portion and the resin layer of the light-shielding printing portion. In the photocuring of the photocurable resin composition, it is preferred to perform light irradiation from the side or light irradiation from the side of the transparent surface material simultaneously with the side. In addition, when curing with a photocurable resin composition for forming a resin layer, or when curing of the photocurable resin composition is required, the light for forming a resin layer may be used. After the hardening of the curable resin composition is substantially completed, the sealing portion is cured by irradiation with light from the side.

[Specific example]

In the production method of the present embodiment, the first surface material can be arbitrarily used as a back material or a surface material. Therefore, the display device can be manufactured in accordance with the following two methods in accordance with the selection of the first face material.

(α-1) The first surface material is a display element (back surface material), and the second surface material is a method of using a transparent surface material (surface material) which is a protective sheet.

(α-2) The first surface material is a transparent surface material (surface material) serving as a protective sheet, and the second surface material is a method using a display element (back surface material).

Hereinafter, a method of manufacturing the display device of Fig. 1 will be specifically described using a pattern (α-1) as an example.

(Step (a))

As shown in FIG. 3 and FIG. 4, the photocurable resin composition for forming a sealing portion is applied to the peripheral edge portion of the display element 50 (first surface material) by a dispenser (not shown) or the like to form an unformed portion. The sealing portion 12 is hardened.

A wiring member such as an FPC that transmits an electrical signal for activating the display element is provided on the outer peripheral portion of the display element. In the manufacturing method of the present embodiment, when the surface materials are held, the arrangement of the wiring members is facilitated, and it is preferable that the display elements are disposed as the first surface material and disposed on the lower side.

(Step (b))

Next, as shown in FIG. 5 and FIG. 6, the resin layer-forming photocurable resin composition 14 is supplied to the rectangular region 13 surrounded by the unhardened sealing portion 12 of the display element 50. The supply amount of the resin layer-forming photocurable resin composition 14 is set in advance to a space sealed by the uncured seal portion 12, the display element 50, and the transparent surface material 10 (see Fig. 7), and can be formed by a resin layer. The amount filled with the photocurable resin composition 14.

As shown in Fig. 5 and Fig. 6, the supply layer of the resin layer-forming photocurable resin composition 14 is such that the display element 50 is laid flat on the lower fixed plate 18, and is linear by the dispenser 20 that moves in the horizontal direction. The strip-shaped or dot-shaped supply resin layer forming photocurable resin composition 14 is used.

The dispenser 20 is configured to be horizontally movable over the entire range of the region 13 by a known horizontal movement mechanism including a pair of guide screws 22 and a guide screw 24 orthogonal to the guide screw 22. Alternatively, instead of the dispenser 20, a die coater can be used instead.

(Step (c))

Next, as shown in FIG. 7, the display element 50 and the transparent surface material 10 (the second surface material) are carried into the decompression device 26. An upper platen 30 having a plurality of suction pads 32 is disposed on an upper portion of the pressure reducing device 26, and a lower platen 31 is disposed at a lower portion thereof. The upper plate 30 is movable in the vertical direction by the air cylinder 34.

The transparent face material 10 is attached to the adsorption pad 32. The display element 50 is fixed to the lower fixed plate 31 with the surface of the resin layer-forming photocurable resin composition 14 facing upward.

Next, the air in the decompression device 26 is sucked by the vacuum pump 28. After the ambient pressure in the decompression device 26 reaches the decompression environment of, for example, 15 to 40 Pa, the transparent surface material 10 is sucked and held by the adsorption pad 32 of the upper platen 30, and the display element is placed toward the lower side. 50, causing the cylinder 34 to start and descend. Then, the display element 50 and the transparent surface material 10 are overlapped with each other via the uncured seal portion 12 to form a laminated precursor, and the laminated precursor is held for a predetermined period of time under a reduced pressure atmosphere.

In addition, the mounting position of the display element 50 to the lower fixed plate 31, the number of the adsorption pads 32, and the mounting position of the transparent surface material 10 to the upper fixed plate 30, etc., match the size and shape of the display element 50 and the transparent surface material 10. And adjust it appropriately. In this case, the electrostatic chuck is used in the adsorption pad, and the glass substrate can be stably maintained in a reduced pressure environment by the electrostatic chuck holding method described in the specification attached to Japanese Patent Application No. 2008-206124 (incorporating this specification).

(Step (d))

Next, after the inside of the decompression device 26 is formed, for example, at atmospheric pressure, the laminated precursor is taken out from the decompression device 26. When the laminated precursor is placed in an atmospheric pressure environment, the surface on the display element 50 side of the laminated precursor and the surface on the side of the transparent surface material 10 are conveniently pressed by atmospheric pressure, and the resin layer in the sealed space is formed by photohardening. The resin composition 14 is pressurized by the display element 50 and the transparent face material 10. By this pressure, the resin layer forming photocurable resin composition 14 in the sealed space flows, and the entire sealed space is uniformly filled with the resin layer forming photocurable resin composition 14.

Then, a light-shielding printing portion is provided on the transparent surface material, and when the uncured seal portion held by the light-shielding portion and the photo-curable resin composition for resin layer formation are cured first, as shown in FIG. The uncured seal portion 12 and the resin layer-forming photocurable resin composition 14 which are sandwiched between the light-shielding portion 55 and the display element 50 are disposed on the side of the precursor, and the display element is exposed to light (ultraviolet rays, or Irradiation of visible light of 450 nm or less and irradiation of light (ultraviolet rays or visible light of 450 nm or less) to the resin layer forming photocurable resin composition 14 through the light transmitting portion 56 from the side of the transparent surface material 10 The display device 1 is obtained by curing the uncured seal portion 12 inside the precursor and the photocurable resin composition 14 for forming a resin layer.

When the light-shielding printing portion is not provided on the transparent surface material, the laminated precursor is entirely irradiated with light from the side of the transparent surface material 10, and the uncured sealing portion 12 and the resin layer are formed in the laminated precursor. The photocurable resin composition 14 is cured to obtain a display device 1.

As described above, the method of manufacturing the display device of the present embodiment will be specifically described as an example of the method (α-1), and the display device can be manufactured in the same manner as in the case of the other method (α-2).

[Effects: Manufacturing method of display device]

According to the method of manufacturing the display device of the present embodiment described above, it is possible to manufacture a display device having a large area without generating bubbles in the resin layer. It is assumed that even if bubbles remain in the photocurable resin composition for forming a resin layer which has been sealed under reduced pressure, the pressure is applied to the photocurable resin composition for forming a resin layer which is sealed under a high pressure environment before curing. The volume of the bubble can be reduced, and the bubble can be easily eliminated. For example, in a photocurable resin composition for forming a resin layer which is sealed at 100 Pa, the volume of gas in the bubble can be considered to be 1/1000 at 100 kPa. Since the gas is dissolved in the photocurable resin composition for forming a resin layer, the gas in the fine volume bubbles is quickly dissolved in the resin layer-forming photocurable resin composition and disappears.

In addition, even if a pressure such as an atmospheric pressure is applied to the resin layer forming photocurable resin composition after sealing, the liquid resin composition for forming a liquid resin layer is still a fluid composition, and thus the pressure system is uniformly distributed. On the surface of the display element, stress applied to a part of the surface of the display element which is in contact with the photocurable resin composition for forming a resin layer is not applied, and the risk of damage to the display element is low.

In addition, the interfacial adhesion force between the resin layer formed by curing the resin layer-forming photocurable resin composition and the display element and the transparent surface material is higher than the interfacial adhesion force by thermal fusion bonding. In addition, the photocurable resin layer-forming photocurable resin composition is pressed and adhered to the surface of the display element or the transparent surface material, and is cured in this state, whereby a higher interfacial adhesion force can be obtained. It is found that the surface of the display element and the transparent face material is uniform, and the locality of the interface is less likely to decrease.

Therefore, there is a low possibility that peeling occurs on the surface of the resin layer, and there is a low possibility that water or corrosive gas is infiltrated from a portion where the interface adhesion is insufficient.

In addition, a method of injecting a photocurable resin composition for forming a fluid resin layer into a narrow and wide area space between two sheets (injection method) causes less generation of bubbles and can be produced in a short time. A photocurable resin composition for forming a resin layer is filled. In addition, the photocurable resin composition for forming a resin layer has a small viscosity limitation, and can easily fill a high-viscosity photocurable resin composition for forming a resin layer. Therefore, a photocurable resin composition for forming a high-viscosity resin layer containing a higher molecular weight curable compound which can increase the strength of the resin layer can be used.

In addition, the photopolymerization initiator (C2) of the photocurable resin composition for forming a resin layer is absorbed by the photopolymerization initiator (C1) having an absorption wavelength region (λ2) and an uncured seal portion. The wavelength region (λ1) is further on the long wavelength side of the photopolymerization initiator (C2), and the light irradiated from the side of the layered precursor uses the wavelength light and the absorption wavelength in the absorption wavelength region (λ1). Both of the wavelength light in the region (λ2) can sufficiently achieve the wavelength light in the absorption wavelength region (λ2) which is not absorbed by the photopolymerization initiator (C1) of the uncured seal portion. In the photo-curable resin composition for forming a resin layer which is sandwiched between the display elements, the photo-polymerization initiator (C2) having the absorption wavelength region (λ2) can sufficiently perform the photocurable resin for resin layer formation. Hardening of the composition.

[effect: hardening resin composition]

The bonding between the display element and the transparent surface material (protective plate) can reduce the stress on the display element by reducing the shrinkage rate during curing of the curable resin or reducing the elastic modulus of the resin layer after curing. Prevent the display of spots and the like from damaging the display quality. On the other hand, if the elastic modulus of the resin layer is too low, there is a possibility that the display element and the transparent surface material are displaced due to the elastic deformation of the resin layer. Further, according to the findings of the inventors of the present invention, even if the elastic modulus of the resin layer is sufficiently high, when the display device is placed vertically or the like, if the self-weight of the display element is applied to the resin layer for a long time, the resin layer will pass through. Plastic deformation occurs, which may cause a decrease in the accuracy of the joint position of the display element.

On the other hand, in the curable resin composition of the present invention, the storage shear elastic modulus at the time of dynamic viscoelasticity measurement after hardening is 5×10 ² to 1×10 ⁵ Pa, and the loss tangent is 1.4 or less. Thereby, the positional deviation of the face materials from each other (the display element and the protective plate) due to the elastic deformation of the resin layer can be prevented, the stress generated by the hardening shrinkage of the resin layer can be reduced, and the resin can be effectively prevented. The plastic deformation of the layer is caused by the positional displacement of the face materials between the display elements and the protective plate.

In particular, the display element is a liquid crystal display element, or even an IPS (In-plane Switching) liquid crystal display element, or a TN (Twisted Nematic) liquid crystal display element having an optical film whose viewing angle is improved on the display surface. In the case where the stress applied to the display element is liable to adversely affect the display quality, the bonding resin layer is preferably a low modulus of elasticity.

Therefore, in the display device using the curable resin composition of the present invention, the display element is preferably a liquid crystal display element, more preferably an IPS type liquid crystal display element or a TN type liquid crystal display element.

In addition, the non-curable component which does not undergo a curing reaction with the curable compound (II) at the time of curing, which is contained in the photocurable resin composition for forming a resin layer, has 0.8 to 3 hydroxyl groups per molecule. The non-hardening oligomer and the hydroxyl group which does not react when hardened in the curable compound (II) can suppress the loss of the tangent (tan δ) of the resin layer after hardening, and can reduce the storage shear elasticity. The modulus of the photocurable resin composition for forming a resin layer when uncured is good, and the viscosity can be lowered, and the uniformity of the curing reaction at the time of curing can be obtained.

When the stability at the time of hardening is good and the uniformity of the hardening reaction at the time of hardening is good, a resin layer having good transparency can be easily obtained. When the photocurable resin composition for forming a resin layer which is not cured is low in viscosity, the occurrence of bubbles can be easily suppressed, and a good interfacial bonding force between the face material and the resin layer can be easily obtained.

Further, the curable resin composition of the present invention can be applied not only to a display device but also to a laminate in which a pair of face materials are laminated via a resin layer, and the same effect can be obtained.

In addition, the curable resin composition of the present invention may be a thermosetting resin composition. In this case, a known thermosetting group is used as the curable group of the curable compound. Further, it is required to contain a known thermal polymerization initiator. In the above embodiment, when the curable resin composition for forming a resin layer is thermosetting, it is preferable that the curable resin composition for forming a sealing portion is thermosetting.

In particular, since the photocurable resin composition does not require a high temperature at the time of curing, it is preferable from the viewpoint that the high temperature causes less adverse effects on the face material or the like.

In the case of using a photopolymerization initiator and a thermal polymerization initiator, photocuring and thermal curing may be simultaneously performed, or the curing may be performed individually to improve the curability.

In addition, the method of producing a laminate using the curable resin composition of the present invention is not limited to the method of the above embodiment, and a known method can be suitably used.

[Examples]

Hereinafter, an example which is implemented to confirm the effectiveness of the present invention is exemplified. Examples 1 to 4, 8 and 9 are examples, and examples 5 to 7 are comparative examples.

(Measurement method for storing shear modulus and its loss tangent)

The storage shear elastic modulus and the loss tangent (tan δ) of the resin layer after hardening, using a rheometer (Physica MCR301, manufactured by Anton Paar Co., Ltd.), and a photocurable resin composition for forming an uncured resin layer, It is placed in a 0.4 mm gap between the platform made of soda lime glass and the measuring mandrel (D-PP20/AL/S07, manufactured by Anton Paar Co., Ltd.), and is set at the lower part of the platform at 35 ° C in a nitrogen atmosphere. The black lamp (FL15BL, manufactured by Nippon Electric Co., Ltd.) was subjected to a dynamic shear stress of 1 mW/cm ^{2 for} 30 minutes, and the photocurable resin composition for forming a resin layer was cured and measured. When the resin layer forming photocurable resin composition is cured, the position of the mandrel is automatically tracked and adjusted so that stress does not occur in the normal direction of the mandrel.

The irradiation intensity was measured on a platform on which a photocurable resin composition for forming a resin layer was placed, using an illuminometer (manufactured by USHIO Electric Co., Ltd., UV intensity meter UNI METER UIT-101).

(quantitative average molecular weight)

The number average molecular weight of the oligomer was determined by using a GPC apparatus (HLC-8020, manufactured by TOSOH Co., Ltd.).

(viscosity)

The viscosity of the photocurable resin composition was measured by an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., RE-85U).

(haze value)

The haze value was determined by using Haze-Gard II manufactured by Toyo Seiki Seisakusho Co., Ltd., and measuring according to ASTM D1003.

[example 1] (display component)

The liquid crystal display element was taken out from a commercially available 17-inch liquid crystal monitor (V137b, manufactured by Acer Co., Ltd.). The display mode of the liquid crystal display device is TN (Twisted Nematic), and the size of the display portion is 338 mm long and 270 mm wide. A polarizing plate is bonded to both surfaces of the liquid crystal display element, and six FPCs for driving are bonded to one side of the long side, and three FPCs for driving are joined to one side of the short side, and the FPC end is joined to the long side. Printed circuit board. This liquid crystal display element is referred to as "display element A".

(glass plate)

In the peripheral portion of one of the surface of the soda-lime glass having a length of 355 mm, a width of 290 mm, and a thickness of 2.8 mm, the light-transmitting portion is formed into a frame-shaped light-shielding printing portion by ceramic printing containing a black pigment so as to have a length of 340 mm and a width of 272 mm. A glass plate B to be a protective sheet is produced.

(Photocurable resin composition for sealing portion formation)

A difunctional polypropylene glycol having a molecular end added to ethylene oxide and having 2 hydroxyl groups in one molecule (number average molecular weight calculated from hydroxyl value: 4000, ethylene oxide content in polypropylene glycol molecule 24 mass) %), mixed with hexamethylene diisocyanate according to a molar ratio of 6 to 7, followed by acrylic acid The ester (IBXA, manufactured by Osaka Organic Chemical Industry Co., Ltd.) is diluted, and a prepolymer is obtained by reacting at 70 ° C in the presence of a catalyst of a tin compound, and 2-hydroxyethyl acrylate is used in the prepolymer. A molar ratio of 1 to 2 was added, and 0.03 parts by mass of 2,5-di-t-butylhydroquinone (polymerization terminator) was added, and the reaction was carried out at 70 ° C, whereby 30% by mass of acrylic acid was obtained. different A solution of an ester-diluted urethane acrylate oligomer (hereinafter referred to as "UC-1"). The hardening base of UC-1 is 2, and the number average molecular weight is about 55,000. The viscosity of the UC-1 solution at 60 ° C is about 580 Pa‧s.

90 parts by mass of UC-1 solution and 2-hydroxybutyl methacrylate (LIGHT ESTER, manufactured by Kyoeisha Chemical Co., Ltd.) HOB) 10 parts by mass was uniformly mixed to obtain a mixture. 100 parts by mass of this mixture and 3 parts by mass of 1-hydroxy-cyclohexyl-phenyl-ketone (photopolymerization initiator, manufactured by Ciba Super Chemical Co., Ltd., IRGACURE 184) were uniformly mixed to obtain photocurability for forming a sealing portion. Resin composition C.

In a state in which the photocurable resin composition C for sealing portion formation is placed in a container, it is placed in a decompression device in an open state, and the pressure in the decompression device is reduced to about 20 Pa for 10 minutes, thereby performing defoaming. deal with. The viscosity of the photocurable resin composition C for sealing portion formation at 25 ° C was measured, and it was about 1300 Pa s.

(Photocurable resin composition for resin layer formation)

A difunctional polypropylene glycol having ethylene oxide added to the end of the molecule and having 2 hydroxyl groups in one molecule (number average molecular weight calculated from hydroxyl value: 4000, ethylene oxide content in polypropylene glycol molecule 24) % by mass, mixed with isophorone diisocyanate in a ratio of 4 to 5 molar ratio, and reacted at 70 ° C in the presence of a catalyst of a tin compound to obtain a prepolymer in which the prepolymer is obtained. 2-hydroxyethyl acrylate was added to a molar ratio of 1 to 2, and 0.03 parts by mass of 2,5-di-t-butylhydroquinone (polymerization terminator) was added, and the reaction was carried out at 70 ° C. A urethane acrylate oligomer (hereinafter referred to as "UA-2") was obtained. The hardening base of UA-2 is 2, the number average molecular weight is about 24,000, and the viscosity at 25 ° C is about 830 Pa‧s.

40 parts by mass of UA-2, 2-hydroxybutyl methacrylate (made by Kyoeisha Chemical Co., Ltd., LIGHT ESTER) 30 parts by mass of HOB) and 30 parts by mass of n-dodecyl methacrylate are uniformly mixed, and bis(2,4,6-trimethylbenzylidene)-benzene is uniformly dissolved in 100 parts by mass of the mixture. Phosphine oxide (photopolymerization initiator, manufactured by Ciba Super Chemical Co., Ltd., IRGACURE 819) 0.5 parts by mass, and n-dodecyl mercaptan (chain transfer agent, manufactured by Kao Corporation, THIOKALCHOL 20) 0.5 parts by mass, a photocurable resin composition PD was obtained.

Next, 60 parts by mass of the PD meter, which is the same as the user of the UA-2 synthesis, is modified with ethylene oxide and has two hydroxyl groups in one molecule (calculated from the hydroxyl value). The number average molecular weight: 4000, the ethylene oxide content in the polypropylene glycol molecule is 24% by mass) 40 parts by mass is uniformly dissolved, and the photocurable resin composition D for forming a resin layer is obtained.

In the state where the resin layer-forming photocurable resin composition D is placed in a container, it is placed in a decompression device in an open state, and the inside of the decompression device is decompressed to about 20 Pa for 10 minutes, thereby performing defoaming. deal with. The viscosity of the photocurable resin composition D for forming a resin layer at 25 ° C was measured and found to be 1.7 Pa s.

In addition, the photopolymerization initiator (the IRGACURE 819) used for the resin layer-forming photocurable resin composition D is a photopolymerization initiator which is used for the photocurable resin composition C for sealing portion formation (the aforementioned IRGACURE 184) has an absorption wavelength region (about 380 nm or less) and an absorption wavelength region (about 440 nm or less) on the longer wavelength side.

Then, the viscoelastic property of the photocurable resin composition D for resin layer formation after photohardening was measured by a rheometer, and the storage shear modulus was 1.0 × 10 ⁴ Pa, and the loss tangent (tan δ) was 0.83.

(Step (a))

The photocurable resin composition C for sealing portion formation is applied by a dispenser to cover the entire circumference of the image display area of the display element A at a position of about 4 mm, and the coating thickness is about 0.6 mm. Hardened seal.

(Step (b))

The resin layer-forming photocurable resin composition D was supplied to a plurality of places in a plurality of places in the inner region of the image display region of the display element A.

While the resin layer forming photocurable resin composition D is being supplied, the shape of the unhardened sealing portion is maintained.

(Step (c))

In the pressure reducing device provided with a pair of fixed lifting devices, the display element A is laid flat on the upper surface of the lower fixed plate in such a manner that the surface of the resin layer forming photocurable resin composition D faces upward.

The glass plate B is placed on the lower side of the lifting device in the decompression device so that the surface on one side of the light-shielding printing portion faces the display element A, and the glass plate B is used when viewed from above. The light-transmitting portion where the light-shielding portion is not provided is held in such a manner that the image display region of the display element A has a margin of about 1 mm and is located at the same position and a distance from the display element A in the vertical direction is 30 mm.

The decompression device was sealed and evacuated until the pressure in the decompression device became about 10 Pa. The upper and lower fixed plates were brought close to each other by the elevating device in the decompression device, and the display element A and the glass plate B were laminated with the resin layer forming photocurable resin composition D, and pressure-bonded at a pressure of 2 kPa, and held for 1 minute. The electrostatic chuck is deenergized, the glass plate B is separated from the upper plate, and the inside of the decompression device is returned to atmospheric pressure in about 15 seconds, thereby obtaining the resin layer by the display element A, the glass plate B, and the uncured seal portion. The laminated precursor E in which the photocurable resin composition D is sealed.

In the laminated precursor E, the shape of the uncured seal portion is substantially maintained in an initial state.

(Step (d))

The uncured seal portion (the photocurable resin composition C for sealing portion formation) provided on the peripheral edge portion of the display element A of the laminated precursor E is arranged linearly from the side of the display element A using the ultraviolet light LED. An ultraviolet light source (manufactured by Spectrum Illumination Co., Ltd., LL146-395), which irradiated the entire portion of the unhardened seal portion with light for about 10 minutes, hardened the seal portion. The intensity of the irradiation light was measured by using an illuminometer (UV-M02, light receiver UV-42, manufactured by ORC Co., Ltd.), and the result was about 1 mW/cm ² . After the seal was hardened, the laminated precursor E was left to stand horizontally for about 10 minutes.

From the laminated precursor E to one side of the glass plate B side, the ultraviolet light from the black lamp and the visible light of 450 nm or less are uniformly irradiated for 30 minutes, and the resin layer forming photocurable resin composition D is cured to form a resin layer. The display device F is obtained. The display device F has no defects such as residual bubbles in the resin layer, although it is not necessary to carry out the step of removing the bubbles required for the production by the injection method. Further, there has been no defect such as leakage of the photocurable resin composition for forming a resin layer from the sealing portion. Further, the thickness of the resin layer became a target thickness (about 0.4 mm).

In place of the display element A, a glass plate having substantially the same size was used instead, and a transparent laminate was produced in the same manner. The haze value at the portion where the light-shielding portion was not printed was measured, and as a result, it was 1% or less, which was a good transparency.

The display device F is returned to the casing of the liquid crystal monitor from which the liquid crystal display element is taken out, and after the wiring is connected again, the liquid crystal monitor is placed so that the display element A bonded to the glass plate B is vertical. After standing for 5 days, cut into the power supply to obtain a good display image covering the display screen in a uniform manner, and the display contrast is higher than the original state. Even if the finger is strongly pressed against the image display surface, the image is not disturbed, and the glass plate B effectively protects the display element A.

Next, the display device F was placed in the same manner, and after one month, the bonding position of the display element was confirmed, and no positional deviation was observed, and the glass plate was favorably held.

[Example 2] (Photocurable resin composition for resin layer formation)

40 parts by mass of UA-2 used in Example 1 and 2-hydroxybutyl methacrylate (LIGHT ESTER, manufactured by Kyoeisha Chemical Co., Ltd.) HOB) 30 parts by mass, and 30 parts by mass of n-dodecyl methacrylate are uniformly mixed, and then uniformly dissolving bis(2,4,6-trimethylbenzylidene)-benzene in 100 parts by mass of the mixture The photo-curable resin composition PG was obtained in 0.5 part by mass of a phosphine oxide (photopolymerization initiator, manufactured by Ciba Super Chemical Co., Ltd., IRGACURE 819).

Next, 40 parts by mass of a PG meter, a difunctional polypropylene glycol having a molecular end modified by ethylene oxide and having two hydroxyl groups in one molecule, which is the same as the user of the UA-2 synthesis, was calculated from the hydroxyl value. The number average molecular weight: 4000, the ethylene oxide content in the polypropylene glycol molecule is 24% by mass), 60 parts by mass is uniformly dissolved, and the photocurable resin composition G for forming a resin layer is obtained.

In a state where the resin layer-forming photocurable resin composition G is placed in a container, it is placed in a decompression device in an open state, and the inside of the decompression device is depressurized to about 20 Pa for 10 minutes, thereby performing defoaming. deal with. The viscosity of the photocurable resin composition G for forming a resin layer at 25 ° C was measured and found to be 1.3 Pa ‧ s.

Then, the viscoelastic property of the photocurable resin composition G for resin layer formation after photohardening was measured by a rheometer, and the storage shear modulus was 3.7 × 10 ³ Pa, and the loss tangent (tan δ) was 0.61.

In the same manner as in Example 1, except that the composition C was used for the photocurable resin composition for sealing portion formation, and the composition G was used for the photocurable resin composition for resin layer formation, the same as in Example 1 was used to obtain the display. Device H.

The display device H is returned to the casing of the liquid crystal monitor from which the liquid crystal display element is taken out, and after the wiring is connected again, the liquid crystal monitor is provided such that the display element A bonded to the glass plate B is vertical. After standing for 5 days, the power is cut in, and a good display image covering the display screen is obtained, and the display contrast is higher than the original state. Even if the finger is strongly pressed against the image display surface, the image is not disturbed, and the glass plate B effectively protects the display element A.

Next, the display device H was set in the same manner, and after one month, the bonding position of the display element was confirmed, and no positional shift or the like was observed, and the glass plate was favorably held.

[Example 3] (Photocurable resin composition for resin layer formation)

A difunctional polypropylene glycol having a molecular end added to ethylene oxide and having 2 hydroxyl groups in one molecule (number average molecular weight calculated from hydroxyl value: 4000, ethylene oxide content in polypropylene glycol molecule 24 mass) %), mixed with isophorone diisocyanate according to a molar ratio of 3 to 4, and reacted at 70 ° C in the presence of a catalyst of a tin compound to obtain a prepolymer in which the prepolymer is obtained. 2-hydroxyethyl acrylate was added in a molar ratio of approximately 1 to 2, and 0.03 parts by mass of 2,5-di-t-butylhydroquinone (polymerization terminator) was added, and the reaction was carried out at 70 ° C. A urethane acrylate oligomer (hereinafter referred to as "UA-3") was obtained. The hardening base of UA-3 is 2, the number average molecular weight is about 21,000, and the viscosity at 25 ° C is about 350 Pa‧s.

80 parts by mass of UA-3, 2-hydroxybutyl methacrylate (made by Kyoeisha Chemical Co., Ltd., LIGHT ESTER) HOB) 20 parts by mass is mixed, and then bis(2,4,6-trimethylbenzylidene)-phenylphosphine oxide is uniformly dissolved in 100 parts by mass of the mixture (photopolymerization initiator, Ciba super chemistry The company's product, IRGACURE 819), 0.5 parts by mass, gave a photocurable resin composition PI.

Next, 30 parts by mass of PI, and a bifunctional polypropylene glycol having two hydroxyl groups in one molecule (number average molecular weight calculated from a hydroxyl value: 2000, EO content in polypropylene glycol: 0% by mass) 70 parts by mass After uniformly dissolving, the photocurable resin composition I for forming a resin layer was obtained.

In the state where the resin layer-forming photocurable resin composition I is placed in a container, it is placed in a decompression device in an open state, and the pressure in the decompression device is reduced to about 20 Pa for 10 minutes, thereby performing defoaming. deal with. The viscosity of the photocurable resin composition I for forming a resin layer at 25 ° C was measured and found to be 2.0 Pa s.

Then, the viscoelastic property after photocuring of the photocurable resin composition I for forming a resin layer was measured by a rheometer. As a result, the storage shear modulus was 2.5 × 10 ⁴ Pa, and the loss tangent (tan δ) was 0.06.

In the same manner as in Example 1, except that the composition C was used for the photocurable resin composition for forming a sealing portion, and the composition I was used for the photocurable resin composition for forming a resin layer, the same results as in Example 1 were obtained. Device J.

The display device J is returned to the casing of the liquid crystal monitor from which the liquid crystal display element is taken out, and after the wiring is connected again, the liquid crystal monitor is provided such that the display element A bonded to the glass plate B is vertical. After standing for 5 days, the power is cut in, and a good display image covering the display screen is obtained, and the display contrast is higher than the original state. Even if the finger is strongly pressed against the image display surface, the image is not disturbed, and the glass plate B effectively protects the display element A.

Next, the display device J was placed in the same manner, and after one month, the bonding position of the display element was confirmed, and no positional shift or the like was observed, and the glass plate was favorably held.

[Example 4] (Photocurable resin composition for resin layer formation)

20 parts by mass of the PI used in Example 3 and a bifunctional polypropylene glycol having two hydroxyl groups in one molecule (number average molecular weight calculated from a hydroxyl value: 2000, EO content in polypropylene glycol: 0% by mass) 80 When the mass part is uniformly dissolved, the photocurable resin composition I2 for resin layer formation is obtained.

In a state where the resin layer-forming photocurable resin composition I2 is placed in a container, it is placed in a decompression device in an open state, and the inside of the decompression device is depressurized to about 20 Pa for 10 minutes, thereby performing defoaming. deal with. The viscosity of the photocurable resin composition I2 for forming a resin layer at 25 ° C was measured and found to be 1.0 Pa ‧ s.

Then, the viscoelastic property after photocuring of the photocurable resin composition I2 for resin layer formation was measured by a rheometer, and as a result, the storage shear modulus was 4.0 × 10 ³ Pa, and the loss tangent (tan δ) was 0.07.

In the same manner as in Example 1, except that the composition C was used for the photocurable resin composition for forming a sealing portion, and the composition I2 was used for the photocurable resin composition for forming a resin layer, the same results as in Example 1 were obtained. Device J2.

The display device J2 is returned to the casing of the liquid crystal monitor from which the liquid crystal display element is taken out, and after the wiring is connected again, the liquid crystal monitor is provided such that the display element A bonded to the glass plate B is vertical. After standing for 5 days, the power is cut in, and a good display image covering the display screen is obtained, and the display contrast is higher than the original state. Even if the finger is strongly pressed against the image display surface, the image is not disturbed, and the glass plate B effectively protects the display element A.

Next, the display device J2 was set in the same manner, and after one month, the bonding position of the display element was confirmed, and no positional shift or the like was observed, and the glass plate was favorably held.

[Example 5] (Photocurable resin composition for resin layer formation)

40 parts by mass of UA-2 used in Example 1 and 2-hydroxybutyl methacrylate (LIGHT ESTER, manufactured by Kyoeisha Chemical Co., Ltd.) HOB) 20 parts by mass, and 40 parts by mass of n-dodecyl methacrylate are uniformly mixed, and then uniformly dissolving bis(2,4,6-trimethylbenzylidene)-benzene in 100 parts by mass of the mixture Phosphine oxide (photopolymerization initiator, manufactured by Ciba Super Chemical Co., Ltd., IRGACURE 819) 0.3 parts by mass, 2,5-di-tert-butylhydroquinone (polymerization terminator) 0.04 parts by mass, n-dodecylsulfide Alcohol (chain transfer agent, made by Kao Corporation, THIOKALCHOL 20) 0.5 parts by mass and 0.3 parts by mass of a UV absorber (TINUVIN 109, manufactured by Ciba Super Chemical Co., Ltd.) to obtain a photocurable resin composition K for forming a resin layer.

In the state where the resin layer-forming photocurable resin composition K is placed in a container, it is placed in a decompression device in an open state, and the inside of the decompression device is decompressed to about 20 Pa for 10 minutes, thereby performing defoaming. deal with. The viscosity of the photocurable resin composition K for forming a resin layer at 25 ° C was measured and found to be 2.0 Pa s.

Then, the viscoelastic property of the photocurable resin composition for resin layer formation K after light curing was measured using a rheometer. As a result, the storage shear modulus was 1.6 × 10 ⁵ Pa, and the loss tangent (tan δ) was 0.44.

In the same manner as in Example 1, except that the composition C was used for the photocurable resin composition for forming a sealing portion, and the composition K was used for the photocurable resin composition for forming a resin layer, the same results as in Example 1 were obtained. Device L.

The display device L is returned to the casing of the liquid crystal monitor from which the liquid crystal display element is taken out, and after the wiring is connected again, the liquid crystal monitor is provided such that the display element A bonded to the glass plate B is vertical. After standing for 5 days, the power was cut in, and a part of the display screen showed a display spot, especially in the peripheral portion of the display screen at the time of halftone display. At the portion where the display spot does not appear, an image with a higher contrast than the initial one can be obtained.

Next, the display device L was set in the same manner, and after one month, the bonding position of the display element was confirmed, and the positional shift or the like was not observed, and the glass plate was favorably held.

[Example 6] (Photocurable resin composition for resin layer formation)

The photocurable resin composition PG used in Example 2 is used as a photocurable resin composition M for forming a resin layer.

In a state where the resin layer-forming photocurable resin composition M is placed in a container, it is placed in a decompression device in an open state, and the inside of the decompression device is decompressed to about 20 Pa for 10 minutes, thereby performing defoaming. deal with. The viscosity of the photocurable resin composition M for forming a resin layer at 25 ° C was measured and found to be 2.2 Pa s.

Then, the viscoelastic property after photohardening of the photocurable resin composition M for forming a resin layer was measured using a rheometer. As a result, the storage shear modulus was 3.1 × 10 ⁵ Pa, and the loss tangent (tan δ) was 0.32.

In the same manner as in Example 1, except that the composition C was used for the photocurable resin composition for forming a sealing portion, and the composition M was used for the photocurable resin composition for forming a resin layer, the same results as in Example 1 were obtained. Device N.

The display device N is returned to the casing of the liquid crystal monitor from which the liquid crystal display element is taken out, and after the wiring is connected again, the liquid crystal monitor is provided such that the display element A bonded to the glass plate B is vertical. After standing for 5 days, the power was cut in, and a part of the display screen showed a display spot, especially in the peripheral portion of the display screen at the time of halftone display. At the portion where the display spot does not appear, an image with a higher contrast than the initial one can be obtained.

Next, the display device N was set in the same manner, and after one month, the bonding position of the display element was confirmed, and no positional shift or the like was observed, and the glass plate was favorably held.

[Example 7] (Photocurable resin composition for resin layer formation)

40 parts by mass of UA-2 used in Example 1 and 2-hydroxybutyl methacrylate (LIGHT ESTER, manufactured by Kyoeisha Chemical Co., Ltd.) HOB) 20 parts by mass, and 40 parts by mass of n-dodecyl methacrylate are uniformly mixed, and then uniformly dissolving bis(2,4,6-trimethylbenzylidene)-benzene in 100 parts by mass of the mixture Phosphine oxide (photopolymerization initiator, manufactured by Ciba Super Chemical Co., Ltd., IRGACURE 819) 0.3 parts by mass, and n-dodecyl mercaptan (chain transfer agent, manufactured by Kao Corporation, THIOKALCHOL 20) 1.5 parts by mass, a photocurable resin composition O for forming a resin layer was obtained.

In a state where the resin layer-forming photocurable resin composition O is placed in a container, it is placed in a decompression device in an open state, and the inside of the decompression device is depressurized to about 20 Pa for 10 minutes, thereby performing defoaming. deal with. The viscosity of the photocurable resin composition O for resin layer formation at 25 ° C was measured and found to be 1.9 Pa s.

Then, the viscoelastic property after photocuring of the photocurable resin composition for forming a resin layer was measured by a rheometer. As a result, the storage shear modulus was 7.5 × 10 ³ Pa, and the loss tangent (tan δ) was 1.8.

In the same manner as in Example 1, except that the composition C was used for the photocurable resin composition for sealing portion formation, and the composition O was used for the photocurable resin composition for resin layer formation, the same results as in Example 1 were obtained. Device P.

The display device P is returned to the casing of the liquid crystal monitor from which the liquid crystal display element is taken out, and after the wiring is connected again, the liquid crystal monitor is provided such that the display element A bonded to the glass plate B is vertical. After about 1 hour, the bonding position of the display element was confirmed, and as a result, the glass plate was offset by a few mm, and the display element could not be satisfactorily held on the glass plate.

Here, the display device P is placed horizontally with the display element A bonded to the glass sheet B, and after the power is left for 5 days, the power supply is cut, and as a result, the offset of the display element does not change, and the center portion of the display screen can be homogenized. Good display image, and the display contrast is higher than the original state. Even if the finger is strongly pressed against the image display surface, the image is not disturbed, and the glass plate B effectively protects the display element A.

[Example 8]

In addition to the case of the synthesis of UA-2 in the case of the synthesis of UA-2, the substituted terminal of the difunctional polypropylene glycol to which ethylene oxide is added is used instead of adding ethylene oxide to the terminal of the molecule and having one molecule 2 hydroxy bifunctional polypropylene glycol (number average molecular weight calculated from hydroxyl value 5500), and approximately the same amount containing 2,2,4-trimethyl-hexamethylene diisocyanate and 2,4,4 A mixture of trimethyl-hexamethylene diisocyanate was synthesized in the same manner as in Example 1 except that the mixture was mixed at a molar ratio of 1:2 to synthesize a urethane acrylate oligomer (UA-4). The hardening base of UA-4 is 2, the number average molecular weight is about 16,000, and the viscosity at 25 ° C is about 39 Pa‧s.

In the same manner as in Example 1, except that UA-2 was used instead of UA-2, the photocurable resin composition PQ for resin layer formation was obtained. 40 parts by mass of the PQ meter, the same molecular end as the user of the UA-4 synthesis, did not add ethylene oxide and had two hydroxyl groups in one molecule of the difunctional polypropylene glycol (calculated from the hydroxyl value) The number average molecular weight was 5,500), and the photocurable resin composition Q for resin layer formation was obtained. The viscosity of the photocurable resin composition Q for forming a resin layer at 25 ° C is 0.8 Pa ‧ s.

The viscoelastic property of the photocurable resin composition for forming a resin layer after Q-light curing was measured by a rheometer. As a result, the storage shear modulus was 2.4 × 10 ⁴ Pa, and the loss tangent (tan δ) was 0.13.

In the same manner as in Example 1, except that the composition C was used for the photocurable resin composition for forming a sealing portion, and the composition Q was used for the photocurable resin composition for forming a resin layer, the same results as in Example 1 were obtained. Device R.

The display device R is returned to the casing of the liquid crystal monitor from which the liquid crystal display element is taken out, and after the wiring is connected again, the liquid crystal monitor is placed so that the display element A bonded to the glass plate B is vertical. After standing for 5 days, the power is cut in, and a good display image covering the display screen is obtained, and the display contrast is higher than the original state. Even if the finger is strongly pressed against the image display surface, the image is not disturbed, and the glass plate B effectively protects the display element A.

Next, the display device R was placed in the same manner, and after one month, the bonding position of the display element was confirmed, and no positional deviation was observed, and the glass plate was favorably held.

[Example 9]

In addition to a difunctional polypropylene glycol having a hydroxyl group at the terminal of the molecule and having two hydroxyl groups in one molecule (a number average molecular weight calculated from a hydroxyl value of 2000), and isophorone diisocyanate, The urethane acrylate oligomer (UA-5) was synthesized in the same manner as in Example 1 except that 6 molar ratios were mixed. The hardening base of UA-5 is 2, the number average molecular weight is about 18,000, and the viscosity at 25 ° C is about 620 Pa‧s.

In the same manner as in Example 1, except that UA-2 was used instead of UA-2, the photocurable resin composition PS for resin layer formation was obtained. Using 40 parts by mass of the PS meter, the same molecular end of the user of the UA-5 was synthesized without the addition of ethylene oxide and the bifunctional polypropylene glycol having 2 hydroxyl groups in one molecule (the amount calculated from the hydroxyl value) An average molecular weight of 2000) 30 parts by mass, and a difunctional polypropylene glycol having a molecular weight greater than that of the user at the time of synthesis of UA-5 without the addition of ethylene oxide and having two hydroxyl groups in one molecule (calculated from the hydroxyl value) The number average molecular weight of 5500) was 30 mass parts, and the photocurable resin composition S for resin layer formation was obtained. The viscosity of the photocurable resin composition S for forming a resin layer at 25 ° C is 0.9 Pa ‧ s.

The viscoelastic property of the photocurable resin composition S for resin layer formation after photohardening was measured by a rheometer, and as a result, the storage shear modulus was 2.0 × 10 ⁴ Pa, and the loss tangent (tan δ) was 0.15.

In the same manner as in Example 1, except that the composition C was used for the photocurable resin composition for sealing portion formation, and the composition S was used for the photocurable resin composition for resin layer formation, the same results as in Example 1 were obtained. Device T.

The display device T is returned to the casing of the liquid crystal monitor from which the liquid crystal display element is taken out, and after the wiring is connected again, the liquid crystal monitor is provided such that the display element A bonded to the glass plate B is vertical. After standing for 5 days, the power is cut in, and a good display image covering the display screen is obtained, and the display contrast is higher than the original state. Even if the finger is strongly pressed against the image display surface, the image is not disturbed, and the glass plate B effectively protects the display element A.

Next, the display device T was set in the same manner, and after one month, the bonding position of the display element was confirmed, and no positional shift or the like was observed, and the glass plate was favorably held.

The curable compound (II) of the present invention and the non-curable oligomer (D) are contained, and the content of the (D) is in the range of 10 to 90% by mass in the curable resin composition, and examples 1 to 4 and 8 and 9. It is known that the stress generated by the shrinkage at the time of hardening of the resin layer can be reduced, and a good display image covering the entire liquid crystal display can be obtained.

Examples 5 and 6 which do not contain the non-curable oligomer (D), although the curable compound (II) of the present invention is contained, have display spots on the peripheral portion of the liquid crystal display screen, and are particularly noticeable in halftone display. It was examined. In addition, in particular, the chain transfer agent contained Example 7 in an amount of more than 1.0 part by mass based on 100 parts by mass of the curable compound (II), and the display element could not be satisfactorily held on the glass plate.

Industrial availability

The curable resin composition of the present invention can be effectively utilized in the production of a laminate used in a display device.

In addition, the contents of the specification, the scope of the application, the drawings and the abstract of the Japanese Patent Application No. 2010-137531, filed on Jun. 16, 2010, are hereby incorporated by reference in .

1. . . Display device

10. . . Transparent surface material

12. . . Unhardened seal

13. . . region

14. . . Photocurable resin composition for resin layer formation

18. . . Lower order

20. . . Distribution machine

twenty two. . . Guide screw

twenty four. . . Guide screw

26. . . Pressure reducing device

28. . . Vacuum pump

30. . . Upper plate

31. . . Lower order

32. . . Adsorption pad

34. . . cylinder

40. . . Resin layer

42. . . Sealing part

50. . . Display component

51. . . Polarizer

52. . . Transparent surface material

53. . . Transparent surface material

54. . . Flexible printed circuit board

55. . . Shading printing section (shading section)

56. . . Translucent part

Fig. 1 is a cross-sectional view showing an example of a display device for protecting a display element by a transparent surface material.

Fig. 2 is a plan view showing the display device of Fig. 1.

Fig. 3 is a plan view showing an example of the aspect of the step (a).

Fig. 4 is a cross-sectional view showing an example of the aspect of the step (a).

Fig. 5 is a plan view showing an example of the aspect of the step (b).

Fig. 6 is a cross-sectional view showing an example of the aspect of the step (b).

Fig. 7 is a cross-sectional view showing an example of the aspect of the step (c).

Fig. 8 is a cross-sectional view showing an example of the aspect of the step (d).

1. . . Display device

10. . . Transparent surface material

40. . . Resin layer

42. . . Sealing part

50. . . Display component

51. . . Polarizer

52. . . Transparent surface material

53. . . Transparent surface material

54. . . Flexible printed circuit board

55. . . Shading printing section (shading section)

56. . . Translucent part

Claims (16)

A resin layer obtained by curing a curable resin composition, wherein the resin layer is characterized by a storage shear modulus of 5 × 10 ² to 2.4 × 10 ⁴ Pa during dynamic viscoelasticity measurement. And the loss tangent is 0.13~1.4. The resin layer according to claim 1, wherein the curable resin composition contains the following curable compound (II) and the following non-curable oligomer (D): curable compound (II): curable One or more kinds of curable compounds which undergo a curing reaction when the resin composition is cured, and at least one of the curable compounds has a hydroxyl group which does not react when the curable resin composition is cured; a non-curable oligomer ( D): an oligomer which does not undergo a curing reaction with the curable compound (II) when the curable resin composition is cured, and has 0.8 to 3 hydroxyl groups per molecule. The resin layer of claim 2, wherein the curable compound (II) contains a monomer having a curable group and having a hydroxyl group. The resin layer of claim 3, wherein the curable compound (II) comprises: an oligomer (A') having a curable group and having a molecular weight of 1,000 to 100,000; and a monomer (B'). It has a hardening group and a molecular weight of 125 to 600, and the monomer (B') contains a monomer (B3) having a hydroxyl group. The resin layer of claim 4, wherein the non-hardening oligomer (D) is a polyoxyalkylene polyol, and the oligomer (A') is a polyoxyalkylene polyol and Amine synthesized by polyisocyanate as raw material Formate oligomer. The resin layer of claim 4, wherein the oligomer (A') has an acrylic group, and at least a part of the monomer (B') has a methacryl group. The resin layer of claim 6, wherein the monomer (B3) contains a hydroxy methacrylate, and the hydroxy methacrylate has a hydroxyalkyl group having 1 to 2 hydroxyl groups and 3 to 8 carbon atoms. The resin layer of claim 7, wherein the monomer (B') contains a monomer selected from the group consisting of alkyl methacrylates having an alkyl group having 8 to 22 carbon atoms ( B4). The resin layer of the eighth aspect of the invention is not a chain transfer agent or a chain transfer agent, but the content thereof is 1 part by mass or less based on 100 parts by mass of the curable compound (II). The resin layer of claim 1 or 2 is photocurable. A laminate in which at least one of the transparent facing materials is laminated by laminating a resin layer as disclosed in any one of claims 1 to 10. A laminate according to claim 11, wherein one of the pair of face materials is a transparent face material, and the other is a display member. The laminate of claim 12, wherein the display element is a liquid crystal display element. A method for producing a laminate comprising: a first face material and a second face material; a resin layer sandwiched between the first face material and the second face material; and a resin layer surrounding the resin layer In the surrounding sealing portion, the manufacturing method includes the steps of: (a) forming a uncured seal portion by applying a curable resin composition for forming a liquid seal portion on a peripheral edge portion of the first face material surface, wherein the liquid seal portion The curable resin composition for forming contains a curable compound (I) and a polymerization initiator; (b) a step of supplying a curable resin composition for forming a resin layer to a region surrounded by the uncured seal; (c) The second surface material is superposed on the curable resin composition for forming a resin layer in a reduced pressure environment of 100 Pa or less, and the resin which has been sealed by the first surface material, the second surface material, and the uncured seal portion is obtained. a step of laminating a precursor of a curable resin composition for forming a layer; and (d) curing the uncured seal portion and the resin layer in a state where the laminated precursor is placed under a pressure of 50 kPa or more. a step of hardening a resin composition, wherein The resin layer obtained by curing the curable resin composition for forming a resin layer, the shear elastic modulus is 5×10 ² to 2.4×10 ⁴ Pa, and the loss tangent is 0.13 to 1.4 in the measurement of dynamic viscoelasticity. . The method for producing a laminate according to claim 14, wherein one of the first surface material and the second surface material is a transparent surface material, and the other is a display element. The method for producing a laminate according to the invention of claim 14 or 15, wherein the curable compound (I) is a photocurable compound; and the curable resin composition for forming a sealing portion contains a photopolymerization initiator (C1) The curable resin composition for forming a resin layer is composed of a curable resin composition as disclosed in claim 10; in the aforementioned step (d), The uncured seal portion and the curable resin composition for forming a resin layer are subjected to light irradiation.