JP2015060000A - Display device manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing, in a relatively short time, a display device in which a photocurable resin composition hardly bulges out from between a transparent face material and the display device, and in which display unevenness hardly occurs.SOLUTION: Provided is a method for manufacturing a display device 1, the method having: (a) a step of applying a coating of a photocurable resin composition including a hardening resin having an average of two or more curable groups per molecule and having an acryloyl group and a methacryloyl group as the curable group, an acryloyl group/methacryloyl group (mole ratio) being 8/2 to 3/7, to the surface of a transparent face material 10 to form a coated film; (b) a step of irradiating the coated film with light and forming a temporarily cured resin layer whose hardening rate is 40-80%; (c) a step of sticking the transparent face material 10 and a display device 20 together via the temporarily cured resin layer; and (d) a step of irradiating the temporarily cured resin layer with light and forming a cured resin layer 30 whose hardening rate is 90% or more.

Description

  The present invention relates to a method for manufacturing a display device in which a display device is protected by a transparent surface material.

The following method is known as a manufacturing method of a display device in which a display device is protected by a transparent surface material.
(A) A step of applying a liquid photocurable resin composition to the surface of a transparent surface material in which a light-shielding portion is formed at the peripheral portion to form a coating film;
(B) irradiating the coating film with light, temporarily curing the photocurable resin composition, and forming a temporarily cured resin layer having a curing rate of 10 to 80%;
(C) a step of bonding the transparent surface material and the display device through the temporarily cured resin layer;
(D) A process for forming a cured resin layer having a curing rate of 90% or more by irradiating the coating film with light, and a method for producing a display device (Patent Document 1).

Japanese Patent No. 5138820

However, the method described in Patent Document 1 has the following problems.
In the Example of patent document 1, what has only a methacryloyl group is used as a curable oligomer. In this case, since the reactivity of the methacryloyl group is low, if the integrated light quantity in the step (B) decreases, the temporary curing resin layer is not sufficiently cured, and in the step (C), the photocurable resin composition becomes a transparent surface material. It sticks out from the display device. Moreover, it is necessary to increase the total integrated light quantity in the step (B) and the step (D), and it takes time to manufacture.

  On the other hand, when a curable oligomer having only an acryloyl group is used, the reactivity of the acryloyl group is high. Therefore, in the step (B), the light irradiation time is slightly increased and the curing proceeds too much. Since the temporarily cured resin layer that has been cured too much has an increased elastic modulus and becomes hard, when the transparent surface material and the display device are bonded together via the temporarily cured resin layer that has been cured too much, stress is applied to the display device. And display unevenness is likely to occur in the display device. In order to reduce the stress, the pre-cured resin layer may be thickened, but the display device becomes too thick, and the total integrated light quantity in the step (B) and the step (D) needs to be increased. Takes time.

  The present invention provides a method by which a photocurable resin composition is less likely to protrude from between a transparent surface material and a display device, and a display device in which display unevenness is unlikely to occur can be manufactured in a relatively short time.

The display device manufacturing method of the present invention is sandwiched between a first face material and a second face material, one of which is a transparent face material and the other is a display device, and the first face material and the second face material. A method for producing a display device having a cured resin layer, comprising the following steps (a) to (d).
(A) An average of 2 or more curable groups per molecule, an acryloyl group and a methacryloyl group as the curable group, and a molar ratio of acryloyl group to methacryloyl group (acryloyl group / methacryloyl group) is 8 / A step of applying a liquid photocurable resin composition containing a curable resin of 2 to 3/7 and a photopolymerization initiator to the surface of the first face material to form a coating film (however, the first If the face material is a display device, a coating film is formed on the surface on which the image is displayed).
(B) After the step (a), a step of irradiating the coating film with light to temporarily cure the photocurable resin composition to form a temporarily cured resin layer having a curing rate of 40 to 80%.
(C) After the step (b), the step of bonding the first face material and the second face material through the temporarily cured resin layer (however, the second face material is a display device). In this case, the first face material and the second face material are bonded so that the surface on which the image is displayed is in contact with the temporarily cured resin layer).
(D) A step of forming a cured resin layer having a curing rate of 90% or more by irradiating the temporarily cured resin layer with light after the step (c).

The curable resin is preferably a curable oligomer having a number average molecular weight of 1,000 to 100,000.
The curable oligomer is preferably a urethane acrylate oligomer.
As the photopolymerization initiator, a photopolymerization initiator (C1) and an absorption wavelength region (λ2) in which there is at least an absorption wavelength region longer than the absorption wavelength region (λ1) of the photopolymerization initiator (C1) ) Having a photopolymerization initiator (C2) in combination, and the light irradiated in the step (b) is light from a light source having a dominant wavelength in the absorption wavelength region (λ2), It is preferable that the light irradiated in d) is light from a light source having a dominant wavelength in the absorption wavelength region (λ1).

  The first face material is a transparent face material in which a light-shielding portion is formed at a peripheral edge, the second face material is a display device, and in the step (a), the photocurable resin composition is used. On the surface of the first face material on the side where the light shielding part is formed, the entire light-transmitting part surrounded by the light shielding part and at least a part of the light shielding part. It is preferable to apply the coating so as to cover it.

  According to the method for manufacturing a display device of the present invention, it is possible to manufacture a display device in which the photocurable resin composition hardly protrudes from between the transparent surface material and the display device and in which display unevenness hardly occurs in a relatively short time.

It is sectional drawing which shows an example of a display apparatus. It is a top view of the display apparatus of FIG. It is sectional drawing which shows an example of the mode of a process (a). It is sectional drawing which shows an example of the mode of a process (b). It is sectional drawing which shows an example of the mode of a process (c). It is sectional drawing which shows an example of the mode of a process (d). It is a figure which shows the absorption characteristic of IRGACURE (trademark) 184 in an acetonitrile solution. It is a figure which shows the absorption characteristic of IRGACURE (trademark) 819 in an acetonitrile solution.

The following definitions of terms apply throughout this specification and the claims.
The transparent face material (protection plate) and the display device are collectively referred to as “face material”.
Among the face materials, in the production method of the present invention, the face material to which the liquid photocurable resin composition is applied in the step (a) is referred to as “first face material”, and is temporarily cured in the step (c). A face material bonded to the first face material through the resin layer is referred to as a “second face material”.
“Transparent” means having light transparency.
“(Meth) acrylate” means acrylate or methacrylate.

The viscosity of the photocurable resin composition is a value measured using an E-type viscometer at 25 ° C.
The number average molecular weight of the curable oligomer (A1) is a polystyrene-equivalent number average molecular weight obtained by GPC measurement. In addition, in GPC measurement, when the peak of an unreacted low molecular weight component (monomer etc.) appears, this peak is excluded and a number average molecular weight is calculated | required.

The number average molecular weight of the non-curable oligomer (D1) is within one molecule of the hydroxyl value A (KOH mg / g) and non-curable oligomer (D1) measured according to JIS K1557-1 (2007 edition). It is a value calculated by the following formula (1) from the number B of hydroxyl groups.
Number average molecular weight of non-curable oligomer (D1) = 56.1 × B × 1000 / A (1)

The curing rate is the absorption peak height X of 1640 to 1620 cm ⁻¹ from the baseline in the FR-IR measurement chart of the coating film before light irradiation, and FT-IR measurement of the temporarily cured resin layer or the cured resin layer after light irradiation. It is a value calculated by the following formula (2) from the absorption peak height Y of 1640 to 1620 cm ⁻¹ from the baseline in the chart.
Curing rate (%) = (X−Y) / X × 100 (2)

<Display device>
FIG. 1 is a cross-sectional view illustrating an example of a display device according to the present invention, and FIG. 2 is a plan view.
The display device 1 includes a transparent surface material 10 (first surface material or second surface material) having a light-shielding portion 12 formed at the peripheral edge, and a display device 20 (second surface material or first surface material). And a transparent cured resin layer 30 sandwiched between the transparent face material 10 and the display device 20, and a flexible printed wiring board 40 (FPC) equipped with a drive IC for operating the display device 20 connected to the display device 20. Have.

  In the display device 1, the area of the translucent part 14 surrounded by the light shielding part 12 is made smaller than the area of the cured resin layer 30, and the area of the transparent surface material 10 is made larger than the area of the display device 20, The area of the cured resin layer 30 is smaller than the areas of the transparent surface material 10 and the display device 20.

(Transparent surface material)
The transparent surface material is a protective plate that transmits the display image of the display device.
Examples of the transparent surface material include a glass plate or a transparent resin plate, and it has high transparency with respect to light emitted from or reflected from a display device, light resistance, low birefringence, high planar accuracy, and surface scratch resistance. A glass plate is most preferred from the viewpoints of adhesion, high mechanical strength, and sufficient light transmission for curing the photocurable resin composition.

Examples of the material of the glass plate include glass materials such as soda lime glass, and high transmittance glass (white plate glass) having lower iron content and less bluishness is more preferable. Tempered glass may be used to increase safety.
Examples of the material of the transparent resin plate include highly transparent resin materials (such as polycarbonate and polymethyl methacrylate).

  The transparent surface material may be subjected to a surface treatment in order to improve the interfacial adhesive force with the cured resin layer. Examples of the surface treatment method include a method of treating the surface of the transparent surface material with a silane coupling agent.

The transparent surface material may be provided with an antireflection layer on the back surface of the joint surface with the cured resin layer in order to increase the contrast of the display image. The antireflection layer can be provided by a method of directly forming an inorganic thin film on the surface of the transparent surface material, or a method of bonding a transparent resin film provided with the antireflection layer to the transparent surface material.
Depending on the purpose of image display, a part or the whole of the transparent surface material may be colored, or a part or the whole of the transparent surface material may be polished to form a glass to scatter the transmitted light. Further, fine irregularities or the like may be formed on a part or the entire surface of the light to refract or reflect the transmitted light.
An integrated body in which an antireflection film, a colored film, a light scattering film, a photorefractive film, a light reflection film, a polarizing film and the like are bonded to a transparent surface material may be used as the transparent surface material.

  In the case of a glass plate, the thickness of the transparent face material is usually 0.5 to 25 mm from the viewpoint of mechanical strength and transparency. In applications such as television receivers and PC displays used indoors, 1 to 6 mm is preferable from the viewpoint of weight reduction of the display device, and 3 to 20 mm is preferable in public display applications installed outdoors. In the case of a transparent resin plate, 2 to 10 mm is preferable.

(Shading part)
The light shielding portion hides the wiring member and the like connected to the display device so that areas other than the image display area of the display device cannot be viewed from the transparent surface material side. The light-shielding part can be provided on the joint surface of the transparent surface material with the cured resin layer or on the back surface thereof, and in terms of reducing the parallax between the light-shielding part and the image display area, the light-shielding part is bonded to the cured resin layer of the transparent surface material. It is preferable to install on the surface. When the transparent face material is a glass plate, it is preferable to use ceramic printing containing a black pigment in the light shielding part because of high light shielding properties.

(Display device)
In the illustrated display device 20, a transparent substrate 22 provided with a color filter and a transparent substrate 24 provided with a TFT are bonded via a liquid crystal layer 26, and this is sandwiched between a pair of polarizing plates 28. Although it is an example of a device, the display device in the present invention is not limited to the illustrated example.

  In the display device, a display material whose optical state is changed by an external electric signal is sandwiched between a pair of electrodes, at least one of which is a transparent electrode. There are liquid crystal display devices, EL display devices, plasma display devices, electronic ink display devices, and the like depending on the type of display material. In addition, the display device has a structure in which a pair of substrates, at least one of which is a transparent substrate, is bonded, and is arranged so that the transparent substrate side is in contact with the cured resin layer. At this time, in some display devices, an optical film such as a polarizing plate or a retardation plate may be provided on the outermost layer side of the transparent substrate on the side in contact with the cured resin layer. In this case, the cured resin layer is in a state of joining the optical film on the display device and the transparent surface material (protective plate).

A surface treatment may be applied to the bonding surface of the display device with the cured resin layer in order to improve the interfacial adhesive force. The surface treatment may be performed only on the peripheral edge or on the entire surface of the substrate. Examples of the surface treatment method include a treatment method using an adhesion primer or the like which can be processed at a low temperature.
The thickness of the display device is usually 0.4 to 4 mm in the case of a liquid crystal display device operated by TFT, and is usually 0.2 to 3 mm in the case of an EL display device.

(Cured resin layer)
The cured resin layer is a layer formed by curing a liquid photocurable resin composition described later.
In the display device, a photocurable resin composition in which the elastic modulus of the cured resin is low is preferable. When the elastic modulus of the resin is large, there is a possibility that stress generated due to curing shrinkage or the like may adversely affect the display performance of the display device when the resin is cured.

The thickness of the cured resin layer in the translucent part is made larger than the thickness of the light shielding part. 30-2000 micrometers is preferable and, as for the thickness of the cured resin layer in a translucent part, 50-1500 micrometers is more preferable. When the thickness of the cured resin layer is 30 μm or more, the cured resin layer effectively buffers an impact caused by an external force from the transparent surface material side, and the display device can be protected. Further, in the manufacturing method of the present invention, even if foreign matter exceeding the thickness of the cured resin layer is mixed between the transparent surface material and the display device, the thickness of the resin layer does not change greatly, and the light transmission performance is improved. There is little influence. If the thickness of the cured resin layer is 2000 μm or less, air bubbles hardly remain in the cured resin layer, and the entire thickness of the display device does not become unnecessarily thick.
Examples of the method for adjusting the thickness of the cured resin layer include a method for adjusting the supply amount of the liquid photocurable resin composition applied to the first face material.

(shape)
The shape of the display device is usually rectangular.
The size of the display device is 0.5 m × 0.4 m or more in the case of a television receiver using a liquid crystal display device because the manufacturing method of the present invention is particularly suitable for manufacturing a display device having a relatively large area. Is suitable, and 0.7 m × 0.4 m or more is particularly preferable. The upper limit of the size of the display device is often determined by the size of the display device. Also, a display device that is too large is likely to be difficult to handle during installation. The upper limit of the size of the display device is usually about 2.5 m × 1.5 m due to these restrictions.
Although the dimensions of the transparent surface material serving as the protective plate and the display device may be substantially equal, the transparent surface material is often slightly larger than the display device because of the relationship with other housings that house the display device. Conversely, depending on the structure of the other casing, the transparent surface material may be slightly smaller than the display device.

<Manufacturing method of display device>
The manufacturing method of the display device of the present invention is a method having the following steps (a) to (d).
(A) An average of 2 or more curable groups per molecule, an acryloyl group and a methacryloyl group as the curable group, and a molar ratio of acryloyl group to methacryloyl group (acryloyl group / methacryloyl group) is 8 / A step of applying a liquid photocurable resin composition containing a curable resin of 2 to 3/7 and a photopolymerization initiator to the surface of the first face material to form a coating film (however, the first When the face material is a display device, a coating film is formed on the surface on which the image is displayed).
(B) A step of irradiating the coating film with light after the step (a) to temporarily cure the photocurable resin composition to form a temporarily cured resin layer having a curing rate of 40 to 80%.
(C) After the step (b), a step of bonding the first face material and the second face material through a temporarily cured resin layer (however, when the second face material is a display device, The first face material and the second face material are bonded so that the surface on which the image is displayed is in contact with the temporarily cured resin layer).
(D) A step of irradiating the temporarily cured resin layer with light after the step (c) to form a cured resin layer having a curing rate of 90% or more.

(Process (a))
First, the photocurable resin composition is applied to the surface of the first face material to form a coating film that spreads along the surface of the first face material. Whether the transparent face material or the display device is used as the first face material is arbitrary.
When the first face material is a transparent face material, the surface on which the coating film is formed is any one of the two surfaces. In terms of reducing parallax between the light shielding portion and the image display area, the surface on the side where the light shielding portion is formed is preferable. In the case where a coating film is formed on the surface on which the light shielding part is formed, the photocurable resin is used because the peripheral edge of the coating film (cured resin layer) is not visible from the light transmitting part surrounded by the light shielding part. It is preferable to form a coating film by applying the composition so as to cover all of the light transmitting part and at least a part of the light shielding part.
When the first face material is a display device, the surface on which the coating film is formed is the surface on the side where the image is displayed.

The coating amount of the photocurable resin composition is set in advance to an amount that allows a predetermined distance between the first face material and the second face material (that is, the cured resin layer has a predetermined thickness). . At this time, it is preferable to consider in advance volume reduction due to curing shrinkage of the photocurable resin composition. Therefore, the coating amount is preferably an amount that makes the coating film slightly thicker than the predetermined thickness of the cured resin layer.
Examples of the method for applying the photocurable resin composition include dispensing, die coating, printing, curtain coating, and the like, and die coating and curtain coating are preferable because a flat coating film can be easily formed only in a desired region.

The photocurable resin composition is a liquid composition containing a curable resin (A) and a photopolymerization initiator (C) and, if necessary, a monomer (B) and a non-curable resin (D).
The viscosity of the photocurable resin composition is preferably 0.05 to 50 Pa · s, and more preferably 1 to 20 Pa · s. If the viscosity is 0.05 Pa · s or more, the proportion of the monomer (B) described later can be suppressed, and the deterioration of the physical properties of the cured resin layer can be suppressed. Moreover, since the component having a low boiling point is reduced, it is suitable for the reduced pressure lamination method described later. If the viscosity is 50 Pa · s or less, bubbles are unlikely to remain in the cured resin layer.

The curable resin (A) has an average of 2 or more curable groups per molecule, has acryloyl groups and methacryloyl groups as the curable groups, and a molar ratio of acryloyl groups to methacryloyl groups (acryloyl groups / methacryloyl groups). Oligomer or polymer whose group is 8/2 to 3/7. Here, “having acryloyl group and methacryloyl group” means having “acryloyl group and methacryloyl group” as a whole of the curable resin (A). Therefore, the curable resin (A) may contain a molecule whose curable group is only an acryloyl group or a molecule whose curable group is only a methacryloyl group. That is, it is only necessary to have an acryloyl group and a methacryloyl group as a whole by including a plurality of molecules of the curable resin.
If the molar ratio of the acryloyl group to the methacryloyl group is within the above range, the amount of light is adjusted by adjusting the light irradiation amount when the photocurable resin composition is temporarily cured to form the temporary cured resin layer. It is easy to control the curing rate within an appropriate range. The molar ratio of the acryloyl group to the methacryloyl group (acryloyl group / methacryloyl group) is preferably 7/3 to 3.5 / 6.5, and more preferably 6/4 to 4/6.

  As the curable resin (A), a curable oligomer (A1) having a number average molecular weight of 1000 to 100,000 is preferable because the viscosity of the photocurable resin composition is easily adjusted to the above range. The number average molecular weight of the curable oligomer (A1) is preferably 10,000 to 70,000.

  As the curable oligomer (A1), a urethane oligomer having an acryloyl group and a methacryloyl group and having a urethane bond (hereinafter also referred to as urethane acrylate oligomer), poly (meth) acrylate of polyoxyalkylene polyol, poly (meth) polyester polyol ( (Meth) acrylates and the like, and urethane acrylate oligomers are preferred from the viewpoint that the mechanical properties of the cured resin, adhesion to the face material, and the like can be widely adjusted by molecular design of the urethane chain.

  As a method for producing a urethane acrylate oligomer, (i) a urethane or prepolymer obtained by reacting a polyol or a polyisocyanate compound with an index of more than 100 to 150 or less, hydroxy (meth) acrylate and an index of And a method of reacting a compound having an isocyanate group and a (meth) acryloyl group with a polyol such that the index is 100, and the like. The index is a value obtained by dividing the number of moles of isocyanate groups of the polyisocyanate compound by the number of moles of hydroxyl groups of the polyol and multiplying by 100. The method for producing the urethane acrylate oligomer may be any one of (i) and (ii).

Examples of the polyol include polyether polyol, polyester polyol, polycarbonate polyol, and the like. Polyether polyol is preferable, and polyoxyalkylene polyol is more preferable in terms of low viscosity.
As the polyoxyalkylene polyol, those having 2 to 4 hydroxyl groups in one molecule are preferable, and those having 2 to 3 hydroxyl groups are more preferable. If the number of hydroxyl groups is within this range, the number of acryloyl groups or methacryloyl groups contained in the urethane acrylate oligomer can be two or more, that is, an average of two curable groups in the curable resin (A) in one molecule. This can be done.
The oxyalkylene group of the polyoxyalkylene polyol is preferably an oxyethylene group and an oxypropylene group or only an oxypropylene group.
The number average molecular weight of the polyoxyalkylene polyol is preferably 400 to 20000. When the number average molecular weight of the polyoxyalkylene polyol is within this range, the molecular weight of the obtained urethane acrylate oligomer can be adjusted to a preferred range.

  In the above methods (i) and (ii), the molar ratio of hydroxy (meth) acrylate to be reacted is hydroxy acrylate / hydroxy methacrylate = 8/2 to 3/7, whereby the curability contained in the urethane acrylate oligomer. The ratio of groups can be adjusted, that is, the ratio of acryloyl groups and methacryloyl groups of the curable groups of the curable resin (A) can be adjusted.

A curable resin (A) may be used individually by 1 type, and may use 2 or more types together.
30-100 mass% is preferable among the sum total (100 mass%) of curable resin (A) and a monomer (B), and, as for the ratio of curable resin (A), 50-100 mass% is more preferable. If the ratio of curable resin (A) is 30 mass% or more, control of a curing rate will become easy.

The photocurable resin composition may contain a monomer (B) in order to adjust the viscosity of the composition.
125-600 are preferable and, as for the molecular weight of a monomer (B), 140-400 are more preferable. If the molecular weight of the monomer (B) is 125 or more, volatilization of the monomer can be suppressed. If the molecular weight of a monomer (B) is 600 or less, the adhesiveness of a face material and a cured resin layer will become favorable.
As the monomer (B), those having 1 to 3 curable groups per molecule are preferable from the viewpoint of the curability of the photocurable resin composition and the mechanical properties of the cured resin layer.

It is preferable that a monomer (B) contains the monomer (B1) which has a hydroxyl group from the point of the adhesiveness of a face material and a resin layer.
As the monomer (B1) having a hydroxyl group, a hydroxy methacrylate having a hydroxyalkyl group having 1 to 2 hydroxyl groups and 3 to 8 carbon atoms (2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 4-hydroxybutyl methacrylate, 6 -Hydroxyhexyl methacrylate and the like are preferable, and 2-hydroxybutyl methacrylate is particularly preferable.

It is preferable that a monomer (B) contains the alkyl methacrylate (B4) which has a C8-C22 alkyl group from the point of the mechanical characteristic of a cured resin layer.
Examples of the alkyl methacrylate (B4) include n-dodecyl methacrylate, n-octadecyl methacrylate, and n-behenyl methacrylate, and n-dodecyl methacrylate and n-octadecyl methacrylate are preferable.

A monomer (B) may be used individually by 1 type, and may use 2 or more types together.
The proportion of the monomer (B) is preferably 0 to 70 mass%, more preferably 0 to 50 mass%, out of the total (100 mass%) of the thermosetting resin (A) and the monomer (B). When the proportion of the monomer (B4) is 70% by mass or less, the curing rate can be easily controlled.

  As the photopolymerization initiator (C), the photopolymerization resin composition is temporarily cured to form a temporary cured resin layer, so that it is easy to control the curing rate of the temporary cured resin layer within an appropriate range. Photoinitiator (C2) having an initiator (C1) and an absorption wavelength region (λ2) in which at least an absorption wavelength region on the longer wavelength side than the absorption wavelength region (λ1) of the photopolymerization initiator (C1) exists ) In combination. That is, if the light irradiated in the step (b) is light from a light source having a dominant wavelength in the absorption wavelength region (λ2), the photopolymerization initiator (C2) is mainly cured in the step (b). The curing rate can be controlled according to the amount of the photopolymerization initiator (C2). Then, if the light irradiated in the step (d) is light from a light source having a dominant wavelength in the absorption wavelength region (λ1), the remaining photopolymerization initiator (C1) is mainly used in the step (d). This contributes to the curing reaction, and the curing reaction can sufficiently proceed.

  Examples of the photopolymerization initiator (C1) include acetophenone series, ketal series, benzoin or benzoin ether series, phosphine oxide series, benzophenone series, thioxanthone series, and quinone series. A benzoin ether-based photopolymerization initiator is preferable, and an acetophenone-based photopolymerization initiator is particularly preferable from the viewpoint that the curing rate can be increased.

The absorption wavelength region (λ2) of the photopolymerization initiator (C2) may have an absorption wavelength region that overlaps with the absorption wavelength region (λ1) of the photopolymerization initiator (C1).
Examples of the photopolymerization initiator (C2) include acetophenone-based, ketal-based, benzoin or benzoin ether-based, phosphine oxide-based, benzophenone-based, thioxanthone-based, quinone-based photopolymerization initiators, phosphine oxide-based, A thioxanthone photopolymerization initiator is preferable, and a phosphine oxide system is particularly preferable from the viewpoint of suppressing coloring after the photopolymerization reaction.
Among these photopolymerization initiators (C2), those having an absorption wavelength region (λ2) with respect to the photopolymerization initiator (C1) are appropriately selected and used.

A photoinitiator (C1) may be used individually by 1 type, and may use 2 or more types together.
A photoinitiator (C2) may be used individually by 1 type, and may use 2 or more types together.
As for the quantity of a photoinitiator (C), 0.01-10 mass parts is preferable with respect to a total of 100 mass parts of curable resin (A) and a monomer (B), and 0.1-2.5 mass. Part is more preferred.
The mass ratio (C1 / C2) between the photoinitiator (C1) and the photoinitiator (C2) is preferably 1/3 to 20/1, and more preferably 1/1 to 10/1. When there are too many photoinitiators (C2), it will become difficult to control the hardening rate in a process (b). When there are too few photoinitiators (C1) and photoinitiators (C2), the curing rate in the step (b) and the step (d) becomes slow.

The photocurable resin composition suppresses the elastic modulus of the cured resin layer so that the stress generated when the transparent surface material and the display device are bonded does not adversely affect the display performance of the display device. The non-curable resin (D) may be included.
The non-curable resin (D) is an oligomer or polymer having no curable group.

  The non-curable resin (D) does not undergo a curing reaction with the curable resin (A) or the good monomer (B) in the composition at the time of curing the photocurable resin composition from the viewpoint of suppressing the elastic modulus of the cured resin layer. The non-curable oligomer (D1) having a hydroxyl group is preferred.

The number of hydroxyl groups per molecule of the non-curable oligomer (D1) is preferably 0.8 to 3, more preferably 1.8 to 2.3.
The number average molecular weight per hydroxyl group of the non-curable oligomer (D1) is preferably 400 to 8000. If the number average molecular weight per hydroxyl group is 400 or more, the polarity of the non-curable oligomer (D1) does not become too high, and the curable resin (A) and the monomer (B) in the photocurable resin composition It is easy to obtain good compatibility. If the number average molecular weight per hydroxyl group is 8000 or less, it is cured by the interaction between the hydroxyl group derived from the curable resin (A) and the monomer (B) and the hydroxyl group of the non-curable oligomer (D1). The effect of stabilizing the non-curable oligomer (D1) in the resin layer is easily obtained. It is speculated that hydrogen bonds are involved in this interaction.

Examples of the non-curable oligomer (D1) include a high molecular weight polyol, and a polyoxyalkylene polyol, a polyester polyol, and a polycarbonate polyol are preferable.
Examples of the polyoxyalkylene polyol include polyoxyalkylene diols such as polyoxyethylene glycol, polyoxypropylene diol, polyoxypropylene triol, and polyoxytetramethylene glycol.
400-8000 are preferable and, as for the number average molecular weight per hydroxyl group of a polyoxyalkylene polyol, 600-5000 are more preferable.

As the polyester polyol, an aliphatic polyester having a residue of an aliphatic diol such as ethylene glycol, propylene glycol or 1,4-butanediol and a residue of an aliphatic dicarboxylic acid such as glutaric acid, adipic acid or sebacic acid Diols are mentioned.
Examples of the polycarbonate polyol include aliphatic polycarbonate diols having a diol residue such as 1,6-hexanediol, and aliphatic polycarbonate diols such as ring-opening polymers of aliphatic cyclic carbonates.
400-8000 are preferable and, as for the number average molecular weight per hydroxyl group of polyester polyol or polycarbonate polyol, 800-6000 are more preferable.

As the non-curable oligomer (D1), a polyoxyalkylene polyol is preferable, and a polyoxypropylene polyol is particularly preferable because the elastic modulus of the cured resin layer tends to be lower. Further, a part of the oxypropylene group of the polyoxypropylene polyol may be substituted with an oxyethylene group.
It is preferable in terms of compatibility that the curable oligomer (A1) is a urethane oligomer synthesized using polyoxyalkylene polyol and polyisocyanate as raw materials, and the non-curable oligomer (D1) is a polyoxyalkylene polyol. .

Non-curable resin (D) may be used individually by 1 type, and may use 2 or more types together.
The amount of the non-curable resin (D) is preferably 10 to 65 parts by mass and more preferably 20 to 50 parts by mass with respect to 100 parts by mass in total of the curable resin (A) and the monomer (B). When the amount of the non-curable resin (D) is 10 parts by mass or more, the elastic modulus of the cured resin layer tends to be lower. If the quantity of non-curable resin (D) is 65 mass parts or less, hardening of a photocurable resin composition will fully advance.

  Photo-curable resin composition can be used as needed, polymerization inhibitor, photo-curing accelerator, chain transfer agent, light stabilizer (UV absorber, radical scavenger, etc.), antioxidant, flame retardant, adhesion Various additives such as a property improver (such as a silane coupling agent), a pigment, and a dye may be included, and a polymerization inhibitor and a light stabilizer are preferably included. In particular, by including a polymerization inhibitor in a smaller amount than the polymerization initiator, the stability of the photocurable resin composition can be improved, and the molecular weight of the cured resin layer can also be adjusted.

Examples of the polymerization inhibitor include polymerization inhibitors such as hydroquinone (2,5-di-tert-butylhydroquinone, etc.), catechol (p-tert-butylcatechol, etc.), anthraquinone, phenothiazine, hydroxytoluene, and the like. Can be mentioned.
Examples of the light stabilizer include ultraviolet absorbers (benzotriazole series, benzophenone series, salicylate series, etc.), radical scavengers (hindered amine series), and the like.
Examples of the antioxidant include phosphorus-based and sulfur-based compounds.

  The total amount of various additives is preferably 10 parts by mass or less and more preferably 5 parts by mass or less with respect to 100 parts by mass in total of the curable resin (A) and the monomer (B).

(Process (b))
After the step (a), the coating film is irradiated with light (ultraviolet rays, short-wavelength visible light, etc.) to temporarily cure the photocurable resin composition, and a temporarily cured resin layer having a curing rate of 40 to 80% is obtained. Form.
The curing rate of the temporarily cured resin layer is 40 to 80%, preferably 50 to 75%, and more preferably 60 to 70%. When the curing rate of the temporarily cured resin layer is 40% or more, it is difficult for the photocurable resin composition to protrude from between the first face material and the second face material in the step (c). If the curing rate of the temporarily cured resin layer is 80% or less, the display device is unlikely to be stressed when the first face material and the second face material are bonded to each other, and the display is finally obtained. Unevenness is unlikely to occur.

The curing rate can also be controlled within the above range by adjusting the light irradiation amount. Further, since the relationship of irradiation amount (mJ / cm ² ) = light source intensity (mW / cm ² ) × irradiation time (s), the intensity of the light source is increased and the irradiation time is the same light irradiation amount. Can be shortened, or the intensity of the light source can be reduced to increase the irradiation time. When the curable resin (A) is used, the adjustment of the irradiation time and the intensity of the light source can be easily performed because the adjustment of the light irradiation amount is easy.

The light irradiation may be performed from the coating film side, and may be performed from the first surface material side when the first surface material is a transparent surface material. Usually, it is performed directly from the coating film side.
The light is preferably ultraviolet light or visible light of 450 nm or less.

Examples of the light source include an ultraviolet lamp, a high-pressure mercury lamp, and a UV-LED.
When the photopolymerization initiator (C1) and the photopolymerization initiator (C2) are used in combination as the photopolymerization initiator, the light source is preferably a light source having a dominant wavelength in the absorption wavelength region (λ2), and the absorption wavelength A light source having no dominant wavelength in the region (λ1) is more preferable. By using the light source, the photopolymerization initiator (C2) mainly contributes to the curing reaction in the step (b), and the curing rate can be controlled according to the amount of the photopolymerization initiator (C2).

After forming the temporary cured resin layer, a protective film may be attached to the surface of the temporary cured resin layer in order to protect the temporary cured resin layer.
Examples of the material for the protective film include polyethylene, polypropylene, and fluororesin.

(Process (c))
After the step (b), the first face material and the second face material are bonded together via the temporarily cured resin layer.
When the second face material is a display device, the surface on which the image is displayed is in contact with the temporarily cured resin layer.
Bonding may be performed under reduced pressure from the viewpoint that bubbles do not easily remain in the cured resin layer. The reduced pressure atmosphere is preferably 10 to 100 Pa, and more preferably 15 to 40 Pa.
10-80 degreeC is preferable and the temperature of atmosphere has more preferable room temperature.
At the time of bonding, pressure may be applied from the first face material side, from the second face material side, or from both sides.

(Process (d))
After the step (c), the temporarily cured resin layer is irradiated with light to form a cured resin layer having a curing rate of 90% or more.
The curing rate of the cured resin layer is 90 to 100%, preferably 95 to 100%, and more preferably 97 to 100%. If the curing rate of the temporarily cured resin layer is 90% or more, the first face material and the second face material are sufficiently bonded together.
The curing rate can be adjusted by the amount of light irradiation as in the step (b).

The light irradiation is performed from the light-transmitting side of the first face material and the second face material.
Of the first face material and the second face material, the display device does not have light transmittance when not operated, and therefore irradiates light from the side of the transparent face material serving as a protective plate through the light transmitting portion.
Moreover, when the light shielding part is provided in the peripheral part of the transparent surface material, the temporarily cured resin layer sandwiched between the light shielding part and the display device cannot be sufficiently cured only by the light from the light transmitting part of the transparent surface material. Therefore, light may be irradiated from the side of the display device.
The light is preferably ultraviolet light or visible light of 450 nm or less.

Examples of the light source include an ultraviolet lamp, a high-pressure mercury lamp, and a UV-LED.
When the photopolymerization initiator (C1) and the photopolymerization initiator (C2) are used in combination as the photopolymerization initiator, the light source is preferably a light source having a dominant wavelength in the absorption wavelength region (λ1). By using the light source, the remaining photopolymerization initiator (C1) mainly contributes to the curing reaction in the step (d), and the curing reaction can sufficiently proceed.

〔Concrete example〕
In the manufacturing method of the present invention, it is optional to use a transparent surface material or a display device as the first surface material. Therefore, the display device can be manufactured by the following two types of methods, depending on the selection of the first face material.
(Α-1) A method of using a transparent surface material serving as a protective plate as the first surface material and using a display device as the second surface material.
(Α-2) A method in which a display device is used as the first face material and a transparent face material serving as a protective plate is used as the second face material.

  Hereinafter, the method for manufacturing the display device of FIG. 1 will be described in detail with reference to the drawings, taking the method (α-1) as an example.

(Process (a))
As shown in FIG. 3, using a dispenser (not shown) or the like, the photocurable resin composition is shielded from light on the surface of the transparent surface material 10 on which the light shielding portion 12 is formed. A flat coating film 32 is formed by coating so as to cover all of the light transmitting portion 14 surrounded by the portion 12 and part of the light shielding portion 12.
The application amount of the photocurable resin composition is set in advance to an amount that allows a predetermined interval between the transparent surface material 10 and the display device 20 (that is, the cured resin layer 30 has a predetermined thickness). .

(Process (b))
Next, as shown in FIG. 4, the coating film 32 is irradiated with light from the first light source 50 disposed on the coating film 32 side, and the photocurable resin composition is temporarily cured to achieve a curing rate of 40 to 80%. A temporary cured resin layer 34 is formed.

(Process (c))
Next, as shown in FIG. 5, the transparent surface material 10 is stacked on the side of the display device 20 on which the image is displayed via the temporarily cured resin layer 34, and the transparent surface material 10 and the display device 20 are bonded together. .

(Process (d))
Next, as shown in FIG. 6, the temporarily cured resin layer 34 is irradiated with light from the second light source 52 on the transparent surface material 10 side through the light transmitting portion 14, and the cured resin layer 30 having a curing rate of 90% or more. By forming the display device 1, the display device 1 is manufactured.

  Although the method for manufacturing the display device of the present invention has been specifically described above by taking the case of the method (α-1) as an example, the display device can be manufactured in the same manner in the case of the method (α-2).

(Function and effect)
In the manufacturing method of the display device of the present invention described above, the photocurable resin composition has an average of 2 or more curable groups per molecule, and has acryloyl groups and methacryloyl groups as the curable groups. In the step (b), since the acryloyl group and the methacryloyl group containing a curable resin (A) having a molar ratio (acryloyl group / methacryloyl group) of 8/2 to 3/7 is used. First, since the acryloyl group reacts preferentially and the reaction of the methacryloyl group is suppressed, when the temporary curable resin layer is formed by temporarily curing the photocurable resin composition, the curing rate of the temporary curable resin layer is appropriately set. Easy to control to range. That is, since the curing of the temporarily cured resin layer does not proceed excessively and the stress generated by the curing shrinkage is suppressed, when the transparent surface material and the display device are bonded via the temporarily cured resin layer in the step (c), the display is performed. The stress applied to the device is suppressed, and display unevenness hardly occurs in the display device. Moreover, since hardening of a temporary-hardening resin layer progresses moderately, in a process (c), it is hard to protrude a photocurable resin composition from between a transparent surface material and a display device.
Further, since the curable resin (A) has an acryloyl group and a methacryloyl group as a curable group, a display device can be manufactured in a relatively short time compared to the case where a curable resin having only a methacryloyl group is used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by the following description. Examples 1 and 4 are examples, and examples 2, 3, 5, and 6 are comparative examples.

<Evaluation>
(Existence of protrusion)
After the step (d), it was visually confirmed whether or not the resin protruded around the liquid crystal display device.
○: There is no protrusion of resin.
Δ: There is protrusion of resin of less than 1 mm.
X: There is protrusion of resin of 1 mm or more.

(Evaluation of display unevenness)
After the step (d), an image was displayed, and it was visually confirmed whether color unevenness occurred.
○: Color unevenness does not appear at all.
Δ: Slightly visible color unevenness.
X: Color unevenness is clearly visible.

<Photocurable resin composition>
(Photocurable resin composition E-1)
Bifunctional polypropylene glycol (number average molecular weight calculated from hydroxyl value: 10000) and isophorone diisocyanate are mixed at a molar ratio of 4 to 5, and reacted at 70 ° C. in the presence of a tin compound catalyst. A polymer was obtained.

  A urethane acrylate oligomer is prepared by mixing a prepolymer and a mixture of 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate in a molar ratio of 1: 1 at a molar ratio of approximately 1: 2, and reacting at 70 ° C. (Hereinafter referred to as UA-1). The number of curable groups of UA-1 was 2, the number average molecular weight was about 44000, and the viscosity at 25 ° C. was about 250 Pa · s.

  In 30 parts by mass of UA-1, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (photopolymerization initiator (C2), manufactured by Ciba Specialty Chemicals, IRGACURE (registered trademark) 819) 0.04 part by mass, 0.3 part by mass of 1-hydroxy-cyclohexyl-phenyl-ketone (photopolymerization initiator (C1), manufactured by Ciba Specialty Chemicals, IRGACURE® 184), and 2,5 0.08 parts by mass of -di-tert-butylhydroquinone (polymerization inhibitor, manufactured by Tokyo Chemical Industry Co., Ltd.) was uniformly dissolved to obtain a composition PD-1.

  The composition PD-1 and trifunctional polypropylene glycol (non-curable oligomer (D1), number average molecular weight calculated from hydroxyl value: 3000) are uniformly dissolved in the ratio (unit: part by mass) shown in Table 1. To obtain a photocurable resin composition E-1.

(Photocurable resin composition E-2)
Bifunctional polypropylene glycol (number average molecular weight calculated from hydroxyl value: 10000) and isophorone diisocyanate are mixed at a molar ratio of 4 to 5, and reacted at 70 ° C. in the presence of a tin compound catalyst. A polymer was obtained.

  A prepolymer and 2-hydroxyethyl acrylate were mixed at a molar ratio of approximately 1: 2, and reacted at 70 ° C. to obtain a urethane acrylate oligomer (hereinafter referred to as UA-2). The number of curable groups of UA-2 was 2, the number average molecular weight was about 44000, and the viscosity at 25 ° C. was about 255 Pa · s.

  In 30 parts by mass of UA-2, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (photopolymerization initiator (C2), manufactured by Ciba Specialty Chemicals, IRGACURE (registered trademark) 819) 0.04 part by mass, 0.3 part by mass of 1-hydroxy-cyclohexyl-phenyl-ketone (photopolymerization initiator (C1), manufactured by Ciba Specialty Chemicals, IRGACURE® 184), and 2,5 0.08 parts by mass of -di-tert-butylhydroquinone (polymerization inhibitor, manufactured by Tokyo Chemical Industry Co., Ltd.) was uniformly dissolved to obtain a composition PD-2.

  The composition PD-2 and trifunctional polypropylene glycol (non-curable oligomer (D1), number average molecular weight calculated from hydroxyl value: 3000) are uniformly dissolved in the ratio (unit: parts by mass) shown in Table 1. To obtain a photocurable resin composition E-2.

(Photocurable resin composition E-3)
Bifunctional polypropylene glycol (number average molecular weight calculated from hydroxyl value: 10000) and isophorone diisocyanate are mixed at a molar ratio of 4 to 5, and reacted at 70 ° C. in the presence of a tin compound catalyst. A polymer was obtained.

  A prepolymer and 2-hydroxyethyl methacrylate were mixed at a molar ratio of approximately 1: 2, and reacted at 70 ° C. to obtain a urethane acrylate oligomer (hereinafter referred to as UA-3). The number of curable groups of UA-3 was 2, the number average molecular weight was about 44000, and the viscosity at 25 ° C. was about 230 Pa · s.

  In 30 parts by mass of UA-3, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (photopolymerization initiator (C2), manufactured by Ciba Specialty Chemicals, IRGACURE (registered trademark) 819) 0.04 part by mass, 0.3 part by mass of 1-hydroxy-cyclohexyl-phenyl-ketone (photopolymerization initiator (C1), manufactured by Ciba Specialty Chemicals, IRGACURE® 184), and 2,5 0.08 parts by mass of -di-tert-butylhydroquinone (polymerization inhibitor, manufactured by Tokyo Chemical Industry Co., Ltd.) was uniformly dissolved to obtain a composition PD-3.

  In the ratio (unit: part by mass) shown in Table 1, composition PD-3 and trifunctional polypropylene glycol (non-curable oligomer (D1), number average molecular weight calculated from hydroxyl value: 3000) are uniformly dissolved. To obtain a photocurable resin composition E-3.

The absorption characteristics of IRGACURE® 184 and IRGACURE® 819 are shown in FIGS. 7 and 8, respectively.
As shown in the absorption characteristics, IRGACURE (registered trademark) 819 has an absorption wavelength region (approximately 440 nm or less) on the longer wavelength side than the absorption wavelength region (approximately 380 nm or less) of IRGACURE (registered trademark) 184.

<Glass plate with shading part>
A frame-shaped light shielding portion (width of each side: 15 mm) by ceramic printing including black pigment on the peripheral portion of one surface of soda lime glass (length: 250 mm, width: 190 mm, thickness: 1.1 mm) , Thickness: 40 μm).

[Example 1]
(Example 1-1)
Step (a):
Using a resin dispenser, the light curable resin composition E-1 is translucent with the light curable resin composition surrounded by the light shielding portion on the surface of the glass plate with the light shielding portion on the side where the light shielding portion is formed. The coating was applied so as to cover the entire part and a part of the light-shielding part (width of each side: 3 mm) to form a coating film (average thickness: 200 μm). The coating film was formed to be thicker by about 160 μm than the light shielding part (thickness: 40 μm).

Step (b):
By irradiating ultraviolet rays ( ² mW / cm ² ) for 10 seconds from a black light (manufactured by NEC, main wavelength: 365 nm) placed on the coating film side so that the integrated light amount is 20 mJ / cm ² , The photocurable resin composition E-1 was temporarily cured to form a temporarily cured resin layer. The curing rate of the temporarily cured resin layer was about 60%.

Step (c):
A glass plate is placed on a surface on which a polarizing plate of a liquid crystal display device (length: 230 mm, width: 170 mm) is laminated via a temporarily cured resin layer, and is pressed with a rubber roller from the glass plate side. A liquid crystal display device was attached.

Step (d):
The temporarily cured resin layer is completely cured by irradiating the temporarily cured resin layer with ultraviolet rays (100 mW / cm ² ) for 15 seconds from the ultraviolet irradiation device on the glass plate side (manufactured by USHIO, main wavelength: 300 nm) through the light transmitting portion. Then, a cured resin layer was formed to obtain a liquid crystal display device. The curing rate of the cured resin layer was 97%. The evaluation results are shown in Table 2.

(Example 1-2)
The photocurable resin composition E-1 is temporarily cured by irradiating with ultraviolet rays ( ² mW / cm ² ) for 15 seconds so that the integrated light amount in the step (b) is 30 mJ / cm ^2, and the temporary cured resin layer ( A liquid crystal display device was obtained in the same manner as in Example 1-1 except that the curing rate was about 65%. The evaluation results are shown in Table 2.

(Example 1-3)
The photocurable resin composition E-1 is temporarily cured by irradiating with ultraviolet rays ( ² mW / cm ² ) for 20 seconds so that the integrated light amount in the step (b) is 40 mJ / cm ^2, and the temporary cured resin layer ( A liquid crystal display device was obtained in the same manner as in Example 1-1 except that the curing rate was about 70%. The evaluation results are shown in Table 2.

[Example 2]
(Example 2-1)
Step (a):
Using a resin dispenser, the light curable resin composition E-2 is translucent with the light curable resin composition surrounded by the light shielding portion on the surface of the glass plate with the light shielding portion on the side where the light shielding portion is formed. The coating was applied so as to cover the entire part and a part of the light-shielding part (width of each side: 3 mm) to form a coating film (average thickness: 200 μm). The coating film was formed to be thicker by about 160 μm than the light shielding part (thickness: 40 μm).

Step (b):
By irradiating ultraviolet rays ( ² mW / cm ² ) for 10 seconds from a black light (manufactured by NEC, main wavelength: 365 nm) placed on the coating film side so that the integrated light amount is 20 mJ / cm ² , The photocurable resin composition E-2 was temporarily cured to form a temporarily cured resin layer. The curing rate of the temporarily cured resin layer was about 80%.

Step (c):
A glass plate is placed on a surface on which a polarizing plate of a liquid crystal display device (length: 230 mm, width: 170 mm) is laminated via a temporarily cured resin layer, and is pressed with a rubber roller from the glass plate side. A liquid crystal display device was attached.

Step (d):
The temporary cured resin layer is completely cured by irradiating the temporary cured resin layer with ultraviolet rays (100 mW / cm ² ) for 10 seconds from the ultraviolet irradiation device on the glass plate side (manufactured by USHIO, main wavelength: 300 nm) through the translucent part. Then, a cured resin layer was formed to obtain a liquid crystal display device. The curing rate of the cured resin layer was 97%. The evaluation results are shown in Table 2.

(Example 2-2)
The photocurable resin composition E-2 is temporarily cured by irradiating with ultraviolet rays ( ² mW / cm ² ) for 15 seconds so that the integrated light amount in the step (b) is 30 mJ / cm ^2, and the temporary cured resin layer ( A liquid crystal display device was obtained in the same manner as in Example 2-1, except that the curing rate was about 90%. The evaluation results are shown in Table 2.

(Example 2-3)
The photocurable resin composition E-2 is temporarily cured by irradiating with ultraviolet rays ( ² mW / cm ² ) for 20 seconds so that the integrated light amount in the step (b) is 40 mJ / cm ^2, and the temporary cured resin layer ( A liquid crystal display device was obtained in the same manner as in Example 2-1, except that the curing rate was about 95%. The evaluation results are shown in Table 2.

[Example 3]
(Example 3-1)
Step (a):
Using a resin dispenser, the light curable resin composition E-3 is translucent with the light curable resin composition surrounded by the light shielding portion on the surface of the glass plate with the light shielding portion on the side where the light shielding portion is formed. The coating was applied so as to cover the entire part and a part of the light-shielding part (width of each side: 3 mm) to form a coating film (average thickness: 200 μm). The coating film was formed to be thicker by about 160 μm than the light shielding part (thickness: 40 μm).

Step (b):
By irradiating ultraviolet rays ( ² mW / cm ² ) for 10 seconds from a black light (manufactured by NEC, main wavelength: 365 nm) placed on the coating film side so that the integrated light amount is 20 mJ / cm ² , The photocurable resin composition E-3 was temporarily cured to form a temporarily cured resin layer. The curing rate of the temporarily cured resin layer was about 30%.

Step (c):
A glass plate is placed on a surface on which a polarizing plate of a liquid crystal display device (length: 230 mm, width: 170 mm) is laminated via a temporarily cured resin layer, and is pressed with a rubber roller from the glass plate side. A liquid crystal display device was attached.

Step (d):
The temporarily cured resin layer is completely cured by irradiating the temporarily cured resin layer with ultraviolet rays (100 mW / cm ² ) for 30 seconds from the ultraviolet irradiation device on the glass plate side (manufactured by USHIO, main wavelength: 300 nm) through the light transmitting part. Then, a cured resin layer was formed to obtain a liquid crystal display device. The curing rate of the cured resin layer was 97%. The evaluation results are shown in Table 2.

(Example 3-2)
The photocurable resin composition E-3 is temporarily cured by irradiating with ultraviolet rays ( ² mW / cm ² ) for 15 seconds so that the integrated light amount in the step (b) is 30 mJ / cm ^2, and the temporary cured resin layer ( A liquid crystal display device was obtained in the same manner as in Example 3-1, except that the curing rate was about 35%. The evaluation results are shown in Table 2.

(Example 3-3)
The photocurable resin composition E-3 is temporarily cured by irradiating with ultraviolet rays ( ² mW / cm ² ) for 20 seconds so that the integrated light amount in the step (b) is 40 mJ / cm ^2, and the temporary cured resin layer ( A liquid crystal display device was obtained in the same manner as in Example 3-1, except that the curing rate was about 40%. The evaluation results are shown in Table 2.

[Example 4]
(Example 4-1)
Step (a):
Using a resin dispenser, the light curable resin composition E-1 is translucent with the light curable resin composition surrounded by the light shielding portion on the surface of the glass plate with the light shielding portion on the side where the light shielding portion is formed. The coating was applied so as to cover the entire part and a part of the light-shielding part (width of each side: 3 mm) to form a coating film (average thickness: 200 μm). The coating film was formed to be thicker by about 160 μm than the light shielding part (thickness: 40 μm).

Step (b):
By irradiating ultraviolet rays ( ² mW / cm ² ) for 10 seconds from a black light (manufactured by NEC, main wavelength: 365 nm) placed on the coating film side so that the integrated light amount is 20 mJ / cm ² , The photocurable resin composition E-1 was temporarily cured to form a temporarily cured resin layer. The curing rate of the temporarily cured resin layer was about 60%.

  On the surface of the temporarily cured resin layer of the glass plate, a protective film (manufactured by Toseguchi Co., Ltd., Puretech (registered trademark) VLH-9, length: 260 mm, width: 200 mm) is placed, and from the protective film side with a rubber roller The protective film was stuck by applying pressure.

Step (c):
The protective film was peeled from the temporarily cured resin layer of the glass plate.
A glass plate is placed on a surface on which a polarizing plate of a liquid crystal display device (length: 230 mm, width: 170 mm) is laminated via a temporarily cured resin layer, and is pressed with a rubber roller from the glass plate side. A liquid crystal display device was attached.

Step (d):
The temporarily cured resin layer is completely cured by irradiating the temporarily cured resin layer with ultraviolet rays (100 mW / cm ² ) for 15 seconds from the ultraviolet irradiation device on the glass plate side (manufactured by USHIO, main wavelength: 300 nm) through the light transmitting portion. Then, a cured resin layer was formed to obtain a liquid crystal display device. The curing rate of the cured resin layer was 97%. The evaluation results are shown in Table 3.

(Example 4-2)
The photocurable resin composition E-1 is temporarily cured by irradiating with ultraviolet rays ( ² mW / cm ² ) for 15 seconds so that the integrated light amount in the step (b) is 30 mJ / cm ^2, and the temporary cured resin layer ( A liquid crystal display device was obtained in the same manner as in Example 4-1, except that the curing rate was about 65%. The evaluation results are shown in Table 3.

(Example 4-3)
The photocurable resin composition E-1 is temporarily cured by irradiating with ultraviolet rays ( ² mW / cm ² ) for 20 seconds so that the integrated light amount in the step (b) is 40 mJ / cm ^2, and the temporary cured resin layer ( A liquid crystal display device was obtained in the same manner as in Example 4-1, except that the curing rate was about 70%. The evaluation results are shown in Table 3.

[Example 5]
(Example 5-1)
Step (a):
Using a resin dispenser, the light curable resin composition E-2 is translucent with the light curable resin composition surrounded by the light shielding portion on the surface of the glass plate with the light shielding portion on the side where the light shielding portion is formed. The coating was applied so as to cover the entire part and a part of the light-shielding part (width of each side: 3 mm) to form a coating film (average thickness: 200 μm). The coating film was formed to be thicker by about 160 μm than the light shielding part (thickness: 40 μm).

Step (b):
By irradiating ultraviolet rays ( ² mW / cm ² ) for 10 seconds from a black light (manufactured by NEC, main wavelength: 365 nm) placed on the coating film side so that the integrated light amount is 20 mJ / cm ² , The photocurable resin composition E-2 was temporarily cured to form a temporarily cured resin layer. The curing rate of the temporarily cured resin layer was about 80%.

  On the surface of the temporarily cured resin layer of the glass plate, a protective film (manufactured by Toseguchi Co., Ltd., Puretech (registered trademark) VLH-9, length: 260 mm, width: 200 mm) is placed, and from the protective film side with a rubber roller The protective film was stuck by applying pressure.

Step (c):
The protective film was peeled from the temporarily cured resin layer of the glass plate.
A glass plate is placed on a surface on which a polarizing plate of a liquid crystal display device (length: 230 mm, width: 170 mm) is laminated via a temporarily cured resin layer, and is pressed with a rubber roller from the glass plate side. A liquid crystal display device was attached.

Step (d):
The temporary cured resin layer is completely cured by irradiating the temporary cured resin layer with ultraviolet rays (100 mW / cm ² ) for 10 seconds from the ultraviolet irradiation device on the glass plate side (manufactured by USHIO, main wavelength: 300 nm) through the translucent part. Then, a cured resin layer was formed to obtain a liquid crystal display device. The curing rate of the cured resin layer was 97%. The evaluation results are shown in Table 3.

(Example 5-2)
The photocurable resin composition E-2 is temporarily cured by irradiating with ultraviolet rays ( ² mW / cm ² ) for 15 seconds so that the integrated light amount in the step (b) is 30 mJ / cm ^2, and the temporary cured resin layer ( A liquid crystal display device was obtained in the same manner as in Example 5-1, except that the curing rate was about 90%. The evaluation results are shown in Table 3.

(Example 5-3)
The photocurable resin composition E-2 is temporarily cured by irradiating with ultraviolet rays ( ² mW / cm ² ) for 20 seconds so that the integrated light amount in the step (b) is 40 mJ / cm ^2, and the temporary cured resin layer ( A liquid crystal display device was obtained in the same manner as in Example 5-1, except that the curing rate was about 95%. The evaluation results are shown in Table 3.

[Example 6]
(Example 6-1)
Step (a):
Using a resin dispenser, the light curable resin composition E-3 is translucent with the light curable resin composition surrounded by the light shielding portion on the surface of the glass plate with the light shielding portion on the side where the light shielding portion is formed. The coating was applied so as to cover the entire part and a part of the light-shielding part (width of each side: 3 mm) to form a coating film (average thickness: 200 μm). The coating film was formed to be thicker by about 160 μm than the light shielding part (thickness: 40 μm).

Step (b):
By irradiating ultraviolet rays ( ² mW / cm ² ) for 10 seconds from a black light (manufactured by NEC, main wavelength: 365 nm) placed on the coating film side so that the integrated light amount is 20 mJ / cm ² , The photocurable resin composition E-3 was temporarily cured to form a temporarily cured resin layer. The curing rate of the temporarily cured resin layer was about 30%.

  On the surface of the temporarily cured resin layer of the glass plate, a protective film (manufactured by Toseguchi Co., Ltd., Puretech (registered trademark) VLH-9, length: 260 mm, width: 200 mm) is placed, and from the protective film side with a rubber roller The protective film was stuck by applying pressure.

Step (c):
The protective film was peeled from the temporarily cured resin layer of the glass plate.
A glass plate is placed on a surface on which a polarizing plate of a liquid crystal display device (length: 230 mm, width: 170 mm) is laminated via a temporarily cured resin layer, and is pressed with a rubber roller from the glass plate side. A liquid crystal display device was attached.

Step (d):
The temporarily cured resin layer is completely cured by irradiating the temporarily cured resin layer with ultraviolet rays (100 mW / cm ² ) for 30 seconds from the ultraviolet irradiation device on the glass plate side (manufactured by USHIO, main wavelength: 300 nm) through the light transmitting part. Then, a cured resin layer was formed to obtain a liquid crystal display device. The curing rate of the cured resin layer was 97%. The evaluation results are shown in Table 3.

(Example 6-2)
The photocurable resin composition E-3 is temporarily cured by irradiating with ultraviolet rays ( ² mW / cm ² ) for 15 seconds so that the integrated light amount in the step (b) is 30 mJ / cm ^2, and the temporary cured resin layer ( A liquid crystal display device was obtained in the same manner as in Example 6-1 except that the curing rate was about 35%. The evaluation results are shown in Table 3.

(Example 6-3)
The photocurable resin composition E-3 is temporarily cured by irradiating with ultraviolet rays ( ² mW / cm ² ) for 20 seconds so that the integrated light amount in the step (b) is 40 mJ / cm ^2, and the temporary cured resin layer ( A liquid crystal display device was obtained in the same manner as in Example 6-1 except that the curing rate was about 40%. The evaluation results are shown in Table 3.

  From the results of Tables 2 and 3, in Examples 1 and 4 using a curable resin having an acryloyl group and a methacryloyl group as a curable group, the temporary cured resin layer was cured even if the accumulated amount of ultraviolet rays changed slightly. It can be seen that the rate can be kept within an appropriate range, and as a result, it is possible to manufacture a display device in which the photocurable resin composition is unlikely to protrude from between the transparent surface material and the display device and display unevenness is unlikely to occur.

  ADVANTAGE OF THE INVENTION According to this invention, the trouble at the time of manufacturing the display apparatus with which the display device was protected by the transparent surface material can be eliminated.

DESCRIPTION OF SYMBOLS 1 Display apparatus 10 Transparent surface material 12 Light-shielding part 14 Translucent part 20 Display device 22 Transparent substrate 24 Transparent substrate 26 Liquid crystal layer 28 Polarizing plate 30 Curing resin layer 32 Coating film 34 Temporary curing resin layer 40 Flexible printed wiring board 50 1st Light source 52 Second light source

Claims (5)

A display device having a first face material and a second face material, one of which is a transparent face material and the other being a display device, and a cured resin layer sandwiched between the first face material and the second face material A method of manufacturing
The manufacturing method of a display apparatus which has the following process (a)-(d).
(A) An average of 2 or more curable groups per molecule, an acryloyl group and a methacryloyl group as the curable group, and a molar ratio of acryloyl group to methacryloyl group (acryloyl group / methacryloyl group) is 8 / A step of applying a liquid photocurable resin composition containing a curable resin of 2 to 3/7 and a photopolymerization initiator to the surface of the first face material to form a coating film (however, the first If the face material is a display device, a coating film is formed on the surface on which the image is displayed).
(B) After the step (a), a step of irradiating the coating film with light to temporarily cure the photocurable resin composition to form a temporarily cured resin layer having a curing rate of 40 to 80%.
(C) After the step (b), the step of bonding the first face material and the second face material through the temporarily cured resin layer (however, the second face material is a display device). In this case, the first face material and the second face material are bonded so that the surface on which the image is displayed is in contact with the temporarily cured resin layer).
(D) A step of forming a cured resin layer having a curing rate of 90% or more by irradiating the temporarily cured resin layer with light after the step (c).   The method for manufacturing a display device according to claim 1, wherein the curable resin is a curable oligomer having a number average molecular weight of 1,000 to 100,000.   The method for manufacturing a display device according to claim 2, wherein the curable oligomer is a urethane acrylate oligomer. As the photopolymerization initiator, a photopolymerization initiator (C1) and an absorption wavelength region (λ2) in which there is at least an absorption wavelength region longer than the absorption wavelength region (λ1) of the photopolymerization initiator (C1) And a photopolymerization initiator (C2) having
The light irradiated in the step (b) is light from a light source having a dominant wavelength in the absorption wavelength region (λ2),
The method for manufacturing a display device according to claim 1, wherein the light irradiated in the step (d) is light from a light source having a dominant wavelength in the absorption wavelength region (λ1). . The first face material is a transparent face material in which a light-shielding portion is formed at a peripheral portion,
The second face material is a display device;
In the step (a), the photocurable resin composition is surrounded by the light shielding part on the surface of the first face material on the side where the light shielding part is formed. The manufacturing method of the display apparatus as described in any one of Claims 1-4 which apply | coat so that all the translucent parts and at least one part of the said light-shielding part may be covered, and a coating film is formed.

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