WO2020175196A1

WO2020175196A1 - Electronic substrate and photocurable composition

Info

Publication number: WO2020175196A1
Application number: PCT/JP2020/005876
Authority: WO
Inventors: 眸愛澤
Original assignee: 積水ポリマテック株式会社
Priority date: 2019-02-28
Filing date: 2020-02-14
Publication date: 2020-09-03
Also published as: JP6762600B1; TW202106133A; TWI808307B; JPWO2020175196A1

Abstract

The present invention provides an electronic substrate which has a flexible part that exhibits excellent flexibility. An electronic substrate which is provided with a rigid substrate (12) and a flexible substrate (14) that extends from an end of the rigid substrate (12), while being bonded in an electrically connectable manner, and which is configured such that: an elastic protective member (20a, 20b) is provided on at least one surface from an end of the flexible substrate (14) to a folded part of the flexible substrate (14); and if the flexible substrate (14) is folded to one surface side of the rigid substrate (12) so as to protrude from the end of the rigid substrate, the projection width (40) of the folded part of the flexible substrate (14) protruding beyond the end of the rigid substrate (12) is 100-400 μm.

Description

Specification

Title of invention: Electronic substrate and photocurable composition

Technical field

The present invention relates to an electronic substrate having a flexible portion having excellent flexibility, and a photocurable composition excellent in flexibility and adhesiveness.

Background technology

[0002] An electronic substrate having a flexible portion having flexibility is generally referred to as a flexible substrate (flexible wiring substrate (F Lex ib Le Pr nted C i rcu i ts, hereinafter referred to as "flexible substrate") as the flexible portion. ) Is used. Flexible substrates are usually bendable with a copper foil or other metal conductor circuit formed on a film of polyimide resin or polyester resin, and a cover film of polyimide resin or polyester resin provided as a protective layer. Known as a base plate. For example, in Japanese Unexamined Patent Publication No. 7-106072 (Patent Document 1), a resin composition is used as a protective member for a connecting portion between a rigid portion and a flexible portion in a substrate having a rigid portion and a flexible portion. ing.

[0003] Further, an electronic substrate having a rigid substrate and a flexible substrate provided at an end of the rigid substrate is, for example, a liquid crystal display device, a plasma display device, an organic EL display device, or an RGB inorganic LED mounting type. It is also used in image display devices such as display devices. In this image display device, a panel, which is an image display portion, is used as a rigid substrate, and a flexible substrate electrically connected to an end portion of the panel is provided in order to apply a voltage or a signal to the panel. Here, an anisotropic conductive film is generally used for the connection between the panel and the flexible substrate, and a protective member for insulating protection and adhesive reinforcement of this connection portion is applied. The other end of the flexible board is electrically connected to an electronic circuit board (motherboard or the like). In general, the electronic circuit board is arranged on the back surface of the panel, and therefore, the flexible substrate extending from the panel is used. \¥0 2020/175 196 2 卩 (: 171? 2020 /005876

The board is bent and connected to the electronic circuit board. In addition, in recent years, there has been an increasing demand for downsizing and narrowing of the frame of the image display device, and in order to save space in the non-image display area, the chip-on mounting the driver on the flexible substrate instead of on the conventional panel. A film structure is also used.

[0004] Here, in order to control the bendability of a flexible substrate, Japanese Patent Laid-Open Publication No. 2000-8265 (Patent Document 2) discloses a panel having an electrode lead-out portion and the electrode. An image display device having a flexible substrate connected to a lead portion and a protective layer covering a connecting portion between the flexible substrate and the electrode lead portion, the wettability of the flexible substrate to a resin material is disclosed. Has been done. With the above structure, when the resin material is applied to the flexible substrate, a region where the resin material stably forms the protective layer and a region where the resin material is repelled and the protective layer is not stably formed. As a result, since the flexible substrate is bent with the tip of the protective layer in the flexible substrate having the protective layer as a starting point, the region where the protective layer is formed can be controlled to have a predetermined width. As a result, it is possible to control the protrusion width of the bent portion of the flexible substrate protruding outward from the panel end portion to be small. Prior art documents

Patent literature

[0005] Patent Document 1: Japanese Patent Laid-Open No. 7-106072

Patent Document 2: Japanese Patent Laid-Open No. 20 08 _ 2 6 5 2 8 Summary of Invention

Problems to be Solved by the Invention

By the way, further miniaturization and narrower frame of the image display device are desired. Specifically, there is a strong demand to further reduce the protrusion width of the bent portion of a flexible board that is bent at the end of a rigid board that constitutes an image display device or the like. In response to these demands, the above technology minimizes the outer shape by controlling the outer shape of the protective layer, but in order to further narrow the frame, it is necessary to protect the outer shape. \¥0 2020/175 196 3 卩 (: 171? 2020 /005876

The layers themselves were an obstacle. Further, if the bending radius is forcibly reduced, the protective layer may be damaged or peeled off, and it is difficult to reduce the protruding width of the bent portion.

The present invention has been made to solve the above problems. That is, it is an object of the present invention to provide an electronic substrate having a flexible portion excellent in flexibility and durability, and a photocurable composition excellent in flexibility and adhesion used in a flexible portion.

Means for solving the problem

[0008] The electronic substrate and the photocurable composition according to one embodiment of the present invention that achieves the above object are as follows.

An electronic board according to an aspect of the present invention is an electronic board that includes a rigid board and a flexible board that extends from an end of the rigid board and is electrically connected to the rigid board. An elastic protection member is provided on at least one surface of the bent portion of the flexible substrate, and the flexible substrate is projected from an end of the rigid substrate and bent toward one surface side of the rigid substrate. At this time, the bending width of the bent portion of the flexible substrate protruding from the end portion of the rigid substrate is 100 to 400. In order to set the protrusion width of the bent portion of the flexible substrate protruding from the end of the rigid substrate to be in the range of 100 to 400, a smaller bend from the end of the rigid substrate is used. Even if the flexible substrate is bent at a radius, since the predetermined elastic protection member is provided, it is possible to make it difficult for the bent portion to have a problem. As a result, the protrusion amount of the bent portion of the flexible substrate from the end portion of the rigid substrate can be made smaller and superior in durability as compared with the conventional one.

[0010] The elastic protection member has a Martens hardness measured by a nanoindentation test of from 0.01 to 0.5.

Is. By setting the Martens hardness of the elastic protective member in the range of 0.1 to 0.5, the elastic protective member has excellent flexibility from the end of the rigid substrate to the flexible substrate. \\0 2020/175 196 4 (:171? 2020 /005876

However, the bending radius when the flexible substrate is bent can be made smaller than before. As a result, the protruding width of the bent portion of the flexible board that protrudes outward from the end of the rigid board (that is, the amount of protrusion of the flexible board from the end of the rigid board) is made smaller than in the past. However, it can be made highly durable.

[001 1] The Young's modulus of the elastic protection member is preferably from 0.1 to 3.0 IV! 3. By using the elastic protection member having the Young's modulus in the above range, the elastic protection member has an appropriate hardness, which makes it possible to reduce the bending radius of the flexible substrate as compared with the conventional one. As a result, the protrusion width of the bent portion of the flexible substrate that protrudes outward from the end of the rigid substrate can be made smaller and superior in durability as compared with the conventional one.

[0012] The peeling force of the elastic protection member shows the relationship of the following expression (1).

＞1 0 0 X 4 (Min) +2 5 0 ··· (1)

In the formula,: Peeling force

Mami: Young's modulus

Since the peeling force of the elastic protection member has the relationship of the above formula (1), when the flexible substrate is bent from the end of the rigid substrate, the protection member has a rigid substrate and a flexible substrate more than the conventional one. It is possible to reduce the bending radius of the flexible substrate without peeling off from the flexible substrate. As a result, the protrusion width of the bent portion of the flexible substrate protruding outward from the end portion of the rigid substrate can be made smaller than that of the conventional one, and excellent in durability.

[0013]The flexible substrate is a resin film having a thickness of 15 to 200, and when the flexible substrate is bent, a wiring body is provided on at least one of the folded inner surface and the outer surface of the flexible substrate. It is provided. Examples of the moonlight film include a polyimide film and a polyester film. Even when the flexible substrate is a resin film having the above thickness, the protrusion width of the flexible substrate bent portion can be made smaller than in the conventional case. In addition, by providing an elastic protection member on the inner surface of the flexible printed circuit board, damage to the wiring body is suppressed when it is bent to reduce the bending radius. \¥0 2020/175 196 5 卩 (: 171? 2020 /005876

You can

[0014] A photocurable composition according to one embodiment of the present invention is a photocurable composition that forms an elastic protective layer by being applied to an electronic substrate and then cured by being irradiated with light. Cyclic (meth)acrylic acid ester monomer, monofunctional aliphatic (meth)acrylic acid ester monomer, monofunctional high polar monomer, thermoplastic elastomer, and radical polymerization initiator However, the Martens hardness measured by the nano-indentation test of the cured product after curing is in the range of 0.1 to 0. and said that it is a range of 1_Rei_1 ^2. The photocurable composition according to one aspect of the present invention contains the above-mentioned components and has an uncured viscosity within the above range, so that the amount applied to an electronic substrate can be easily controlled precisely, and Excellent in performance. As a result, in addition to the low possibility of excessive coating on the electronic substrate, the cured product has a Martens hardness within the above range, so that the cured product does not hinder bending. The flexible substrate can be bent with a smaller bending radius.

[0015] The peeling force of the cured product after curing the photocurable composition shows the relationship of the following formula (1).

>100 x 4 (Min) +250 (1)

In the formula,: Peeling force

Mami: Young's modulus

The cured product obtained by curing the photocurable composition is a rigid substrate and a flexible substrate because the peeling force of the cured product of the photocurable composition has the relationship of the above formula (1). It has excellent adhesion to and flexibility, and is difficult to peel off even if the flexible substrate is bent to a small bending radius, and the durability of the electronic substrate can be improved.

[0016] The peeling force of the cured product after curing the photocurable composition shows the relationship of the following formula (2).

<100 X 4 (Min) + 760 (2)

: Peel force

º: Young's modulus (IV! 3) \\0 2020/175 196 6 卩 (: 171? 2020 /005876

The cured product obtained by curing the photocurable composition is a rigid substrate and a flexible substrate because the peeling force of the cured product of the photocurable composition has the relationship of the above formula (2). By not sticking more strongly than necessary, the durability of the electronic board against deformation of the flexible board can be improved, and it can be peeled off from the base material, resulting in excellent repairability.

[0017] An electronic substrate according to an aspect of the present invention is formed by applying the photocurable composition according to any one of the above to a boundary region between the rigid substrate and the flexible substrate. By applying a photocurable composition that exhibits appropriate flexibility when cured to the boundary area, the amount of protrusion of the bent portion of the flexible substrate from the edge of the rigid substrate In comparison, even if it is made smaller, the protective member does not easily come off the rigid board and flexible board. As a result, the protrusion width of the bent portion of the flexible substrate that protrudes outward from the end portion of the rigid substrate can be made smaller and superior in durability as compared with the conventional one. In addition, the photo-curable composition adheres to both the rigid and flexible substrates and is cured, preventing the rigid and flexible substrates from peeling off and damp from the boundary between the rigid and flexible substrates. And foreign matter can be prevented from entering.

Effect of the invention

[0018] In the electronic board according to an aspect of the present invention, even if the protrusion width of the bent portion of the flexible board that protrudes from the end portion of the rigid board is reduced, the protective member may be damaged or peeled off. Absent. In addition, the photocurable composition of one embodiment of the present invention has a low viscosity when uncured, so that it is easy to apply and has excellent workability. Further, the cured product after curing has a desired hardness, durability, and appropriate hardness. The flexibility can be expressed. Brief description of the drawings

[0019] [FIG. 1] A perspective view of an electronic substrate according to an embodiment of the present invention.

[Fig. 2] Fig. 2 is a partial enlarged cross-sectional view taken along the line I-I in Fig. 1 for explaining the configuration of the flexible substrate and the cured body.

[Fig. 3] Fig. 3 is a partially enlarged cross-sectional view for explaining a state in which the flexible substrate is bent, which is a cross-section taken along the line I_I in Fig. 1. \\0 2020/175 196 7 卩 (: 171? 2020 /005876

[FIG. 4] A bending test method, which is one of the evaluation methods in the examples in the present specification, in which a surface on which a cured body functioning as an elastic protection member is formed is bent inward FIG.

[FIG. 5] One of the evaluation methods in the examples of the present specification, which is a bending test method of bending so that the surface on which a cured body that functions as an elastic protection member is formed is the outside FIG.

FIG. 6 is a schematic configuration diagram illustrating the configuration of a test piece to be subjected to a bending resistance test, which is one of the evaluation methods in the examples in the present specification.

[Fig. 7] Fig. 7 is an explanatory view illustrating an outline of a bending resistance test.

FIG. 8 is a graph showing the relationship between the Young's modulus of the elastic protection member and the peeling force.

[FIG. 9] A graph defining the range by classifying the relationship between the Young's modulus of the elastic protection member and the peeling force.

MODE FOR CARRYING OUT THE INVENTION

[0020] [Electronic substrate]

One aspect of the present invention will be described in detail based on an embodiment. An electronic board 10 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. As shown in FIG. 1, an electronic board 10 according to an exemplary embodiment of the present invention includes a rigid board 12 and a flexible board 14 extending from an end of the rigid board 12 and connected in a conductive manner. Equipped with. Further, as shown in FIG. 2, the electronic substrate 10 is provided with an elastic protection member from the end of the flexible substrate 14 to at least one side of the bent portion 16 of the flexible substrate 14. Then, as shown in Fig. 3, when the flexible board 14 is projected from the end of the rigid board 12 and bent toward one side of the rigid board 12, the rigid board 12 is The projecting width 40 of the bent portion of the flexible substrate 14 projecting from the end is 100 to 400. From the viewpoint of miniaturization of the device using the electronic board, when the flexible board 14 is projected from the end of the rigid board 12 and bent toward one side of the rigid board 12, the rigid board 1 The projecting width of the bent portion of the flexible base plate 14 projecting from the end of 2 is preferably 100 to 350, and \\0 2020/175 196 8 卩 (: 171? 2020 /005876

It is preferably 150-350 ^ 01.

[0021] The bent portion 1 of the flexible substrate 1 4 protruding from the end of the rigid substrate 1 2

By setting the protrusion width 40 of 6 in the range of 100 to 400, while maintaining durability against deformation of the connection portion of the rigid substrate 12 and the flexible substrate 14 compared to the conventional one, The board space can be saved. Therefore, when the electronic substrate 10 according to the embodiment of the present invention is used in, for example, an image display device, it is possible to reduce the non-display portion of the panel, so that the image display device can be downsized and the frame can be narrowed. It will be possible.

Next, the electronic substrate 10 used in the image display device will be described as an example with reference to FIGS. 2 and 3. Therefore, the electronic substrate 10 according to the embodiment of the present invention is not limited to the electronic substrates shown in FIGS. As shown in Fig. 2 and Fig. 3, for example, the flexible substrate 14 is connected to the anisotropic conductive film on the electrodes of the liquid crystal display panel or the rigid substrate 12 which is the Mitsuguchi mounting panel by laminating various functional layers on the glass substrate. 1 5 electrically connected. In more detail, in the case of the liquid crystal display panel, Riji' de board 1 2 polarizer 1 2 _3, and the first transparent electrode-coated glass substrate 1 2 spoon, with the second transparent electrode glass substrate 1 2 And a liquid crystal layer sandwiched between the first glass substrate 12 and the second glass substrate 12

An encapsulating material 13 for encapsulating liquid crystal, a polarizing plate 1 ₂₆ and a backlight unit 12 2 arranged on the back surface of the second glass substrate 12 side are sequentially laminated. In the electronic substrate 10 of the present invention, the flexible substrate 14 is provided at the end of the second glass substrate 12 with a transparent electrode via the anisotropic conductive film 15. Furthermore, in order to prevent the anisotropic conductive film 15 from being short-circuited or peeled off, the anisotropic conductive film 15 is covered with an elastic protective member.

There are 20 tanks. The structure of the electronic substrate 10 is not limited to the structure described above, and any structure may be used as long as the rigid substrate 12 is a harder substrate than the flexible substrate 14. As an example, it may be a glass epoxy resin substrate, a phenol resin substrate, a silicon substrate, a ceramics substrate, or the like. Also, in the case of a LCD monitor, the first transparent electrode is attached. \¥0 2020/175 196 9 卩 (: 171? 2020 /005876

The glass substrate 12 is the glass substrate with the first transparent electrode and the color filter, and the glass substrate 12 with the second transparent electrode is the glass substrate with the second transparent electrode and the knife.

[0023] Fig. 2 is a partially enlarged cross-sectional view showing a state before the flexible substrate 14 is bent. The photo-curable composition described below is applied to at least one of the inside and the outside of the bent portion 16 at the connecting portion between the rigid substrate 12 and the flexible substrate 14, and is cured by, for example, ultraviolet rays to give elasticity. Protective member 20

20 pits are formed. The glass substrate with the first transparent electrode 1 2 The boundary side including the tip of the glass substrate with the first transparent electrode 1 2 and the anisotropic conductive film 15 and a part of the flexible substrate 1 2 0 3 so as to cover, it is provided elastic protective member 2 0 _3. On the other hand, on the side of the second glass substrate 12 with a transparent electrode, the boundary including the tip of the second glass substrate 12 with a transparent electrode, the anisotropic conductive film 15 and a part of the flexible substrate 14 is provided. An elastic protective member 20 is provided so as to cover the region 30. As a result, the anisotropic conductive film 15 which electrically connects the rigid substrate 12 and the flexible substrate 14 is sealed by the elastic protective members 20 ₃ and 20.

Next, FIG. 3 shows a state where the flexible substrate 14 is bent in the direction of the white arrow shown in FIG. As shown in FIG. 3, in the flexible substrate 14 where the elastic protection members 2 0 3 and 20 are formed, the flexible substrate 14 and the elastic protection members 2 0 3 and 20 Since it has flexibility, it is projected and bent from the end of the rigid substrate 12 to form a bent portion 16. The distance from the end of the rigid substrate 12 to the protruding end of the bent portion 16 of the flexible substrate 14 at the time of this bending is referred to as the protruding width 40. Then, as described above, the protrusion width 40 is 100 to 400, preferably 100 to 3501, more preferably 150 to 350. 〇 1. In addition, when the surface of the rigid board 12 is viewed from the front (that is, in plan view), the ends of the rigid board 12 are bent in the bending direction in a region where the flexible board 14 and the rigid board 12 overlap. Means the most protruding end. On the other hand, the projecting end of the bent portion 16 of the flexible substrate 14 is similar to the above in plan view. , The surface of the base material (resin film) of the flexible substrate 14 that is the protruding end of the flexible substrate 14 farthest from the end of the rigid substrate 12 and is the outside of the bending. In addition, here, although an example of observing in a plan view is used, the direction of observing the end portion and the protruding end is not limited to the front surface side, and for example, the side surface may be observed.

[0025] <Flexible substrate>

A flexible substrate 14 according to an embodiment of the present invention is a substrate made of a resin film such as a polyimide film or a polyester film, and usually at least a wiring body is formed on the resin film. In the flexible substrate 14 according to the embodiment of the present invention, it is preferable that the wiring body is provided on the polyimide film. Further, the thickness of the flexible substrate 14 is more preferably 15 to 200 Mm. In order to form a predetermined elastic protection member, even if the flexible substrate 14 is a polyimide film having the above-mentioned thickness, the protrusion width 40 of the bent portion 16 of the flexible substrate 14 is , Can be made smaller.

Further, the flexible substrate 14 may include a resist layer in addition to the wiring body. Further, it may be a so-called chip-on-film on which an electronic element is further mounted. In that case, it is preferable that the electronic element is arranged so as to avoid the most bent portion of the bent portion.

[0027] <Elastic protection member>

In the elastic protection member according to the embodiment of the present invention, the martens ^! measured by the nanoindentation test is preferably 0.1 to 0.5 N / mm ² . By setting the Martens hardness of the elastic protection member within the range of 0.1 to 0.5 N/mm ² , the elastic protection member described above has excellent flexibility from the end of the rigid board to the flexible board. In addition to elasticity, it also has extensibility and compressibility, and the bending radius when the flexible substrate is bent can be made smaller than in the past. More specifically, when the elastic protection member is arranged inside the flexible substrate, the elastic protection member is compressed by bending when bent, so that the elastic protection member is bent. \\0 2020/175 196 1 1 卩 (: 171? 2020 /005876

The radius can be reduced. On the other hand, when the elastic protection member is arranged outside the flexible substrate, the bending radius can be reduced by the elastic protection member being stretched with a weak stress when being bent. As a result, the protrusion width 40 of the bent portion of the flexible substrate that protrudes outward from the end of the rigid substrate (that is, the amount of protrusion of the flexible substrate from the end of the rigid substrate) is In comparison, it can be made smaller.

[0028] The Martens hardness is 0.1 to 0.3.

Is more preferable

.. When the elastic protective layer material having the above hardness is used, the bending radius can be reduced with a weak stress. Therefore, the load on the flexible substrate or the rigid substrate is small, and it is suitable for application to, for example, a glass substrate or a thin substrate that is easily damaged. Further, the Martens hardness is 0.3 to 〇.

Although the stress for reducing the bending radius becomes large, it is high in strength and resistant to rubbing, and is suitable for large substrates and applications where shock such as vibration is applied.

[0029] The Young's modulus of the elastic protection member according to the embodiment of the present invention is:

3, preferably from 0.1 to 1.

The range is from 0.1 to 0. 3 1\/1 3. The method of measuring Young's modulus will be described later. By using the elastic protection member having the Young's modulus in the above range, the elastic protection member has an appropriate hardness, which makes it possible to reduce the bending radius of the flexible substrate as compared with the conventional case. As a result, the protrusion width of the bent portion of the flexible substrate that protrudes outward from the end portion of the rigid substrate can be made smaller than in the conventional case.

By the way, the elastic protective layer has a predetermined strength in order to protect the flexible substrate. At this time, it was found that if the strength of the elastic protective layer is increased too much, the elastic protective layer is easily peeled from the flexible substrate when the flexible substrate is bent to have a predetermined protrusion width. As a result of diligent studies by the inventor, when the relationship between the strength (Young's modulus) of the elastic protective layer and the peeling force between the elastic protective layer and the flexible substrate is within a predetermined range, the flexible substrate is provided with a predetermined protrusion width It was found that peeling did not occur even when bent. That is, the elastic protection part \¥0 2020/175 196 12 卩 (: 17 2020 /005876

The peeling force of the material from the flexible substrate can be expressed by the following equation (1).

>100 x 4 (Min) +250 (1)

In the formula,: Peeling force (1\1/○○, Mitsu: Young's modulus

Since the peeling force of the elastic protection member has the relationship of the above formula (1), when the flexible substrate is bent from the end of the rigid substrate, the protection member has a rigid substrate and a flexible substrate more than the conventional one. It is possible to reduce the bending radius of the flexible substrate without peeling off from the flexible substrate. As a result, it is possible to reduce the protrusion width of the bent portion of the flexible substrate that protrudes outward from the end portion of the rigid substrate, while maintaining durability against deformation, as compared with the conventional case. The method for measuring the peeling force will be described later.

[0031] A graph of the relationship between Young's modulus and peeling rate, which will be described later, is shown in Fig. 8. This graph is a graph created based on the samples of the examples of the present specification. As shown in Fig. 8, we found F = 1 O O X I n (Mi) + 250 as a regression line that determines the superiority or inferiority of durability against deformation. If the peeling force of the elastic protective member satisfies the condition of the above formula (1), the flexible substrate is not peeled off when the flexible substrate is bent from the end of the rigid substrate, and the flexible substrate is more flexible than before. The bending radius of can be reduced. Furthermore, we found F = 100 X I n (º) + 760 as a regression line that determines the superiority or inferiority of repairability. If the peeling force of the elastic protection member satisfies the condition of the above-mentioned formula (2), it can be peeled from the base material while having desired hardness and adhesiveness, and can be repaired (repair). Becomes If the peeling force exceeds the regression line, the adhesion of the elastic protection member to the flexible substrate will be too strong, and the elastic protection member will break when attempting to peel it off, making repairing difficult.

Further, as shown in FIG. 9, the elastic protection member according to the embodiment of the present invention is roughly divided into three preferable ranges. That is, the elastic protective member of the present invention has a Young's modulus

Is 1.0 £ £ 3.0 and the peeling \\0 2020/175 196 13 卩 (: 171? 2020 /005876

Is particularly preferable in the range ◯, which is 250 £ £ 800.

Is 0.3 <M £ 1.0 and the peeling force (1\1/

A certain range is more preferable, and Young's modulus is

Is more preferable to be a peeling force (1\1/○○ is 80 ££550), the range 8 is more preferable. The elastic protective member having the property of the above range <3. When used, the stress for reducing the bending radius becomes large, but it is high-strength and resistant to rubbing, and is suitable for a large substrate or an application to which a shock such as vibration is applied. The bending radius can be reduced with weak stress by using an elastic protective layer material that has the property of: Therefore, it is suitable when applied to a glass substrate or a thin substrate that is easily damaged and has a small load on a flexible substrate or a rigid substrate. Therefore, it is preferable to have a range property when downsizing at a high level and co-framed.On the other hand, a range member is an elastic protective member having an intermediate property and has a wide range. It is preferable because it is easy to use for various purposes.

[0033] [Photocurable composition]

The photocurable composition according to one embodiment of the present invention is a photocurable composition that forms a protective layer by applying light to an electronic substrate and then curing the composition. (Meth)acrylic acid ester monomer, monofunctional aliphatic (meth)acrylic acid ester monomer, monofunctional high-polarity monomer, thermoplastic elastomer, and radical polymerization initiator, and the uncured viscosity is 1 〇〜

The Young's modulus of the cured product is in the range of 0.1 to 3.

[0034] Here, the "monofunctional alicyclic (meth)acrylic acid ester monomer" is meant to include a monofunctional alicyclic acrylic acid ester monomer and a monofunctional alicyclic methacrylic acid ester monomer. The “monofunctional aliphatic (meth)acrylic acid ester monomer” is meant to include a monofunctional aliphatic acrylic acid ester monomer and a monofunctional aliphatic methacrylic acid ester monomer. Similarly, “monofunctional highly polar monomer” is meant to include monofunctional highly polar acrylate monomers and monofunctional highly polar methacrylic acid monomers, acrylate monomers. \¥02020/175196 14 卩 (: 171? 2020 /005876

The taste.

[0035] A photocurable composition according to an embodiment of the present invention contains the above-mentioned components and has an uncured viscosity within the above range, so that it is easy to apply and excellent in workability, and after curing. By having the Young's modulus of the cured body of the above range, the cured body has desired flexibility. In addition, the cured product of the photocurable composition of the present invention may be used as an elastic protection member for the electronic substrate 10 described above.

From the viewpoint of coatability of the photocurable composition according to an embodiment of the present invention, the uncured viscosity of the photocurable composition is from 10 to 5000.

Range of 3, preferably 50-2000

It is in the range of 3, and more preferably in the range of 90 to 1000001 33. Especially when the photocurable composition is applied to a predetermined area having unevenness by using a non-contact type coating device such as a jet dispenser so as to have a predetermined thickness, the coating amount can be controlled with high accuracy. Therefore, it is preferable that the viscosity is 90 to 1,000,000 133.

[0037] From the viewpoint of imparting desired flexibility as a cured product, the Young's modulus of the cured product of the photocurable composition is from 0.01 to 3.

The range is 0, preferably 1 to 1.

It is in the range of 3, and more preferably 0,1 to 0.

It is in the range of 3 IV! 8.

[0038] The peeling force of the cured product after curing the photocurable composition shows the relationship of the following formula (1).

> 100 x 4 (Min) + 250 (1)

In the formula,: Peeling force

Mami: Young's modulus

The cured product obtained by curing the photocurable composition has a desired hardness because the peeling force of the cured product of the photocurable composition has the relationship of the above formula (1). While having excellent durability.

[0039] The peeling force of the cured product after curing the photocurable composition shows the relationship of the following formula (2).

<100 X 4 (Mimi) + 7 60 (2)

: Peel force

\¥02020/175196 15 卩 (: 171? 2020 /005876

º: Young's modulus (IV! 3)

Since the peeling force of the cured product of the photocurable composition has the relationship of the following formula (2), the cured product obtained by curing the photocurable composition has desired hardness and adhesion. While having it, it can be peeled off from the base material and has excellent process reworkability (repairability).

[0040] Furthermore, the cured product of the photocurable composition according to one embodiment of the present invention after curing is

As shown in 9, it has three preferable ranges. That is, the cured product of the present invention has a Young's modulus (IV! 3) of 1.0 £ 3.0 and a peeling strength of

Is particularly preferred in the range 〇, which is 250 £ £800.

Is 0.3 <M £ 1.0 and the peeling force is

Is more preferred, with a Young's modulus (IV! 3) of 〇.

1 £ º £ 〇 0.3 and peeling power

Is more preferably 80 £ £550. If an elastic protective member made of a hardened material having the above-mentioned range (3) is formed, the stress for reducing the bending radius increases, but it is high in strength and resistant to rubbing, and large substrates and shocks such as vibration are On the other hand, if an elastic protective member made of a cured material having the properties of the above range 8 is formed, the bending radius can be reduced with a weak stress, so that the load on the flexible substrate or the rigid substrate can be reduced. Therefore, it is suitable when applied to a glass substrate or a thin substrate that is easily damaged, etc. For this reason, it is preferable to have the property of range 8 especially when it is desired to downsize and co-frame at a high level. Range M is a cured product having intermediate properties, and is preferable because it is easy to use in a wide range of applications.

[0041] Next, the components contained in the photocurable composition will be described.

[0042] Monofunctional alicyclic (meth)acrylic acid ester monomer:

The monofunctional alicyclic (meth)acrylic acid ester monomer is a liquid composition and is a component that dissolves the thermoplastic elastomer. In addition, when a monofunctional alicyclic (meth)acrylic acid ester monomer is blended, the adhesive force of the cured product after curing of the photocurable composition is enhanced, and when the cured product is peeled from the adherend. Adhesive residue can be reduced. In addition, the Young's modulus is increased by strengthening the cured body. \\0 2020/175 196 16 卩(: 171? 2020 /005876

Has the effect of In addition, increasing the proportion of this component can increase the moisture resistance.

[0043] Specific examples of the monofunctional alicyclic (meth)acrylic acid ester monomer include isobornyl acrylate, cyclohexyl acrylate, dicyclopentanyl acrylate, 3,3,5-trimethylcyclohexyl acrylate, 4 — ㊀ “1: —Butylcyclohexyl acrylate and the like.

[0044] Monofunctional aliphatic (meth)acrylic acid ester monomer:

The monofunctional aliphatic (meth)acrylic acid ester monomer is a liquid composition and is a component for dissolving the thermoplastic elastomer together with the above-mentioned monofunctional alicyclic (meth)acrylic acid ester monomer. By blending a monofunctional aliphatic (meth)acrylic acid ester monomer, the flexibility of the cured product obtained after curing the photocurable composition can be increased and the Young's modulus can be reduced.

[0045] Specific examples of the monofunctional aliphatic (meth)acrylic acid ester monomer include aliphatic ether (meth)acrylic acid ester monomers such as ethoxydiethylene glycol acrylate, 2-ethylhexyl diglycol acrylate, and butoxyethyl acrylate. And aliphatic hydrocarbon (meth)acrylic acid ester monomers such as lauryl acrylate, stearyl acrylate, isostearyl acrylate, decyl acrylate, isodecyl acrylate, isononyl acrylate, and mono-octyl acrylate. By using the aliphatic hydrocarbon (meth)acrylic acid ester monomer, the compatibility with the soft segment of the thermoplastic elastomer can be increased and the viscosity of the photocurable composition can be lowered.

[0046] Monofunctional highly polar monomer:

The monofunctional highly polar monomer is a liquid composition, and by admixing the monofunctional highly polar monomer, it is possible to enhance the adhesion of the cured product obtained after curing the photocurable composition.

[0047] Specific examples of the monofunctional highly polar monomer include a hydroxyl group-containing acrylic acid ester monomer, a glycidyl group-containing acrylic acid ester monomer, and an acrylic acid. \¥0 2020/175 196 17 卩(: 171? 2020/005876

Examples thereof include a amide-based monomer, a tertiary amino group-containing (meth)acrylic acid ester monomer, and an imide-based (meth)acrylic acid ester monomer. Acrylic amide monomers, tertiary amino group-containing (meth)acrylic acid ester monomers, imide (meth)acrylic acid ester monomers, etc., from the viewpoint of storage stability and adhesion improvement in photocurable compositions. Nitrogen-containing monomers are preferred. Examples include acryloyl morpholine, dimethylaminoethyl (meth) acrylate, and 1\1-acryloyloxyethyl hexahydrophthalimide.

[0048] From the viewpoint of adhesiveness, the monofunctional high-polarity monomer is preferably 0.5% by mass to 12.75% by mass in the photocurable composition, and 2 to 8.5% by mass. It is more preferable. 〇 If it is less than 0.5% by mass, the peeling force is low, so if the deformation is large, it easily peels off at the joint between the rigid and flexible substrates. If it is more than 12.7 5% by mass, the thermoplastic elastomer is used. Since it has low compatibility with, it is feared that the viscosity tends to increase over time, and that the moisture resistance of the cured product may decrease due to the increase in the number of highly polar segments. When the content is in the range of 2 to 8.5% by mass, it is possible to obtain a photocurable composition having a low viscosity, a small viscosity change, and a high adhesiveness.

[0049] Further, the Young's modulus is ◯.

It becomes remarkable for the following photocurable compositions. ○ In the photo-curable composition of less than 3 IV! _{3, the} resistance to shearing force tends to be weak, and the adhesion tends to be low only with the monofunctional (meth)acrylic acid ester monomer. Is.

[0050] The photocurable composition according to one embodiment of the present invention further comprises a polyfunctional aliphatic (meth)acrylic acid ester monomer, a polyfunctional cyclic (meth)acrylic acid ester monomer, a polyfunctional compound such as bismaleimide. A monomer may be included as appropriate. From the viewpoint of the strength of the cured product of the photocurable composition and the reactivity of the photocurable composition, a polyfunctional aliphatic (meth)acrylic acid ester monomer and a polyfunctional cyclic (meth)acrylic acid ester monomer are used. It is preferable that one or more of bismaleimide is 0% by mass to 4.25% by mass in the photocurable composition, either alone or in total. If it is more than 4.2% by mass, the residual tack of the cured product is low. \¥0 2020/175 196 18 卩 (: 171? 2020 /005876

On the other hand, there is a concern that the cured product may undergo curing shrinkage (warpage) or hardness increase.

[0051] Specific examples of the polyfunctional aliphatic (meth)acrylic acid ester monomer include a bifunctional aliphatic (meth)acrylic acid ester monomer. Examples of the bifunctional aliphatic (meth)acrylic acid ester monomer include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, Polypropylene glycol di (meth) acrylate, glycerin di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 3-methyl-1,5-pentanediol di (meth) Acrylate, 1,

6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, and the like. Since the compatibility with the soft segment of the thermoplastic elastomer is relatively high, a bifunctional aliphatic hydrocarbon-based di(meth)acrylic acid ester monomer having a reactive group at both ends is preferable.

[0052] Specific examples of the polyfunctional cyclic (meth)acrylic acid ester monomer include ethoxylated bisphenol octadi(meth)acrylate, propoxylated bisphenol octadi(meth)acrylate, and propoxylated ethoxylated bisphenol octadiene. (Meth) acrylate, ethoxylated isocyanuric acid di/tri (meth) acrylate, £-caprolactone-modified tris-(2-acryloxyethyl) isocyanurate, and the like. As the polyfunctional cyclic (meth)acrylic acid ester monomer, a tris(2-hydroxyethyl)isocyanurate (meth)acrylic acid ester monomer is preferable from the viewpoint of improving adhesion.

[0053] Examples of the bismaleimide include 4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, 2,2-bis [4-(4-maleimide phenoxy)phenyl] Propane, bis (3-ethyl-5-methyl-4-maleimidophenyl) methane, 1, 6-bis (maleimide) \¥0 2020/175 196 19 卩 (: 171? 2020 /005876

Hexane, 1, 6, and bismaleimide (2, 2, 4-trimethyl) hexane are examples. From the point of not easily inhibiting the compatibility and photocurability of the photocurable composition, 1,6-bis(maleimide)hexane, 1,6'-bismaleimide (2

Aliphatic bismaleimides such as, 2,4-trimethyl)hexane are preferred.

[0054] Thermoplastic elastomer:

Examples of the thermoplastic elastomer include styrene-based thermoplastic elastomers, olefin-based thermoplastic elastomers, ester-based thermoplastic elastomers, urethane-based thermoplastic elastomers, amide-based thermoplastic elastomers, vinyl chloride thermoplastic elastomers, and fluororesin-based thermoplastic elastomers. Examples thereof include a plastic elastomer and an ionically crosslinked thermoplastic elastomer. As the thermoplastic elastomer in the present invention, a styrene-based thermoplastic elastomer is preferable.

[0055] The styrenic thermoplastic elastomer includes the monofunctional alicyclic (meth)acrylic acid ester monomer and the monofunctional aliphatic (meth)acrylic acid ester monomer, and the monofunctional high polarity in the photocurable composition. Dissolved in any of the monomers. Then, the styrene-based thermoplastic elastomer is a cured product of the monofunctional alicyclic (meth)acrylic acid ester monomer and the monofunctional aliphatic (meth)acrylic acid ester monomer and the monofunctional highly polar monomer. Improves repairability and lowers moisture permeability. Further, the styrene-based thermoplastic elastomer is dissolved in any of the monofunctional alicyclic (meth)acrylic acid ester monomer and the monofunctional aliphatic (meth)acrylic acid ester monomer and the monofunctional highly polar monomer, and It is a component that imparts rubber elasticity (flexibility and extensibility) to the cured product. In one embodiment of the present invention, the dissolved state may be a state in which it is in a uniform liquid state as a whole, and in addition to the case where it is colorless and transparent, it is clouded with white turbidity or other colors. It is okay.

Since the styrene-based thermoplastic elastomer alone is solid, it does not have adhesiveness at room temperature, but the monofunctional alicyclic (meth)acrylic acid ester monomer and the monofunctional aliphatic (meth)acrylic acid ester monomer are used. And high monofunctionality When dissolved in a polar monomer, it can be uniformly dispersed in the photocurable composition and its cured product, so that it can be contained as one component of the photocurable composition having adhesiveness.

[0057] The addition amount of the styrene-based thermoplastic elastomer is 10 to 3 in the photocurable composition.

It is preferably 5% by mass, more preferably 10 to 20% by mass, and further preferably 10 to 15% by mass. If the content of the styrene-based elastomer is less than 10% by mass, there is a possibility that the bearer property may be lowered. On the other hand, when it exceeds 35% by mass, the viscosity of the photocurable composition becomes high, which may make application difficult. When it is 20% by mass or less, the fluidity is suitable and the coating is easy.

[0058] Specific examples of the styrene-based thermoplastic elastomer include styrene-butadiene-styrene block copolymer (S BS), styrene-isoprene styrene block copolymer (SIS), and styrene-ethylene propylene. Styrene block copolymer (SE BS), styrene-ethylene-propylene styrene block copolymer (SE PS), styrene-isobutylene-styrene block copolymer (S BS), styrene-ethylene- Examples thereof include ethylene-propylene-styrene block copolymer (SEE PS) and modified products thereof.

[0059] Among these, S E B S and S having no unsaturated bond in the soft segment

The use of E PS and S I BS is preferable because the cured product of the photocurable composition has excellent weather resistance. Further, by using one having a high soft segment ratio among SEBS and SEPS, it is possible to enhance the transparency of the cured body. Specifically, the ratio of the mass of the soft segment to the total mass of the thermoplastic elastomer is preferably 80 to 95 mass %. By doing so, for example, the parallel light transmittance (wavelength 55 Onm) of the elastic protective member having a thickness of 0.5 mm can be increased to 90% or more.

[0060] In the present specification, the weight average molecular weight of the styrene-based thermoplastic elastomer is determined by GPC method (Gel Permeation Chromatography; gel permeation chromatography). \¥0 2020/175 196 21 卩 (: 171? 2020 /005876

) And based on a calibration curve (calibration curve) measured with standard polystyrene. In one embodiment of the present invention, it is preferable to use a styrene-based thermoplastic elastomer having a weight average molecular weight of less than 200,000 because the viscosity suitable for coating can be easily adjusted.

[0061] Radical polymerization initiator

As the radical polymerization initiator, specifically, a monofunctional aliphatic (meth)acrylic acid ester monomer and a monofunctional alicyclic (meth)acrylic acid ester monomer, and a monofunctional highly polar monomer are photoreacted by, for example, light rays. A photo-radical polymerization initiator that is allowed to cure is preferable. When the photocurable composition contains a photoradical polymerization initiator, the photocurable composition is irradiated with light rays, for example, the photocurable composition coated on the film-forming target is photocured. And a coating film can be formed. Examples of the photoradical polymerization initiator include benzophenone-based, thioxanthone-based, acetophenone-based, acylphosphine-based, oxime ester-based, and alkylphenone-based photopolymerization initiators. The addition amount of the photo radical polymerization initiator is preferably 0.1 to 10 parts by mass, and 0.5 to 5 parts by mass, based on 100 parts by mass of the total amount of all monomers including monofunctional and polyfunctional. The mass part is more preferable.

[0062] Other ingredients:

The photocurable composition according to one embodiment of the present invention may further contain other components such as various additives as appropriate without departing from the spirit of one embodiment of the present invention. For example, silica, thixotropic agents such as aluminum oxide, plasticizers such as olefin oils and paraffin oils, silane coupling agents and polymerization inhibitors, defoamers, light stabilizers, antioxidants, antistatic agents, Examples include fillers.

[0063] The above embodiment is an example of one embodiment of the present invention, and modifications of the embodiments, addition of known techniques, combinations, and the like can be performed without departing from the spirit of the present invention. Those techniques are also included in the scope of the present invention. Example \¥0 2020/175 196 22 卩 (: 171? 2020 /005876

Next, one embodiment of the present invention will be described in more detail based on examples (comparative examples). The following photo-curable compositions of Sample 1 to Sample 29 and cured products thereof were prepared and evaluated by the evaluation methods described below.

A sample was prepared as shown below.

[0066] Sample 1:

As acrylic monomers, lauryl acrylate, isobornyl acrylate, 1\1_acryloyloxyethyl hexahydrophthalimide, and 1,9-nonanediol diacrylate were prepared. Next, in addition to the above-mentioned monomer, as a thermoplastic elastomer, 3M 3 (styrene-isobutylene-styrene block copolymer) (trade name “3I M 3 3 8 [¾ 10 2C”) Kaneka Co., Ltd.) was added and the mixture was stirred for 24 hours to dissolve the thermoplastic elastomer in the above-mentioned monomer. The blending ratio at this time is as shown in Table 1. When the "resin component" consisting of the above-mentioned monomer and thermoplastic elastomer is 100 parts by mass, the photo radical polymerization initiator phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide is used. And 2-hydroxy-2-methylpropiophenone were added to the above resin components in amounts of 0.40 parts by mass and 3.6 parts by mass, respectively, to obtain a photocurable composition of Sample 1. It was

The obtained photocurable composition of Sample 1 was irradiated with ultraviolet rays under the conditions described below to form an elastic protective member which is a cured product of Sample 1.

[0068] Samples 2 to 28:

Photocurable compositions of Samples 2 to 28 were prepared in the same manner as Sample 1 except that the thermoplastic elastomer of Sample 1 and each monomer were changed to the types and formulations (parts by mass) shown in Tables 2 to 4. .. The photo-curable compositions of Samples 2 to 28 were also irradiated with ultraviolet rays in the same manner as in Sample 1 to form the elastic protective members of Samples 2 to 28 on the polyimide film.

[0069] As Sample 29, a polyurethane methacrylate containing no thermoplastic elastomer was used. \¥02020/175 196 23 卩 (: 17 2020 /005876

A photocurable composition mainly composed of a rate resin and a (meth)acrylic monomer was used.

[0070] Tables 1 to 4 show the compositions of Samples 1 to 29 and the evaluation results. The evaluation method will be described later.

[0071] [Table 1]

\\0 2020/175 196 24 (: 17 2020 /005876

[0072] [Table 2]

[0073] \¥0 2020/175 196 25 卩 (: 17 2020 /005876

[Table 3]

[0074] \\0 2020/175 196 26 卩 (: 17 2020 /005876

[Table 4]

[0075] The raw materials used in Tables 1 to 4 are shown below.

<Thermoplastic elastomer _> \¥02020/175 196 27 卩 (: 171? 2020 /005876

3183, 8 (¾ 102: product name “3 丳3 3/8, ¾ 102 ”, styrene content 15 mass%, weight average molecular weight 90,000, styrene-isoptyrene-styrene block copolymer, Kaneka Corporation

3183 Choha (¾ 103 cho: Product name “3 丨 Miho 3 Choha [¾ 103 cho”), Styrene content 30 mass %, weight average molecular weight 90,000, Styrene-isoptyrene-styrene block copolymer, stock Made by Kaneka

3183 Choha (¾073: Brand name “3 丨3 徳3 Choha [¾073 crocodile”, styrene content 30 mass %, weight average molecular weight 70,000, styrene-isobutylene-styrene block copolymer, Kaneka Corporation Made

3£(^2063: Brand name “3M??Cho 2063”, styrene content 13 mass%, weight average molecular weight 120,000, styrene-ethylene-propylene-styrene block copolymer, Kuraray Co., Ltd. Made

Epofriend Hatcho 501: Product name "Epofriend Hatcho 501", styrene content 40 mass%, weight average molecular weight 90,000, epoxy modified styrene-butadiene-styrene copolymer, manufactured by Daicel Corporation

1 £-2000: Product name "Chomi _ 2000", Polymethadiene with terminal methacryl group (acrylic equivalent 2000), manufactured by Nippon Soda Co., Ltd.

[0076] <Various tests and evaluations>

Manufactured by Mitsumi 〇 1" 1 I 1 n V 88 VI 3. 〇〇 16 6 ”, cone plate “〇 5°/30” ), and light at 23 ^° 〇, 1 07 ”when uncured The viscosity of the curable composition was measured.

[0078] Storage stability:

The photocurable composition was allowed to stand for 2 weeks in an environment of 25°°, and when precipitation or separation could not be visually confirmed, it was evaluated as “8”, and when precipitation or separation could be visually confirmed, it was judged as “Mitsumi”. He said, "He said. \¥02020/175196 28 卩 (: 171? 2020 /005876

[0079] Tensile breaking elongation (%), tensile strength

100% elongation tensile stress 〇\/1 a) and Young's modulus (IV! 3):

The mechanical strength of the cured product was determined by changing "3 <625 1 :2010". Thickness on silicone release treated polyester film 1

And then apply the photocurable composition,

The photocurable composition is cured by irradiating it with UV light for 15 seconds at ◯○^, and the obtained cured product is punched out with a dumbbell-shaped No. 8 mold, and the rod-shaped part of the dumbbell-shaped sample is filled with 16 Marks were attached at intervals to prepare test pieces. Speed 200111111/111 丨

Tensile test was performed to measure tensile elongation at break (elongation at break), tensile strength (maximum tensile stress), 100% elongation tensile stress, and Young's modulus (elastic modulus). The tensile elongation at break, the tensile strength, and the 100% elongation tensile stress were calculated by applying the following equations (1), (2), and (3), respectively. Young's modulus was obtained by dividing the tensile stress within the tensile proportional limit by the strain.

Ding 3 = ○ 1--Formula (1)

○!: Maximum tensile force (1\!)

3: Initial cross-sectional area of test piece (〇! ² )

Minoru: Tensile elongation at break (%)

!- 0: Initial distance between marked lines (01111)

!- 1: Distance between marked lines at break (○!○○

731 00: 100% elongation tensile stress (IV! 3)

100: 100% elongation tensile force (1\!)

[0080] Martens hardness (1\1/○1○1 ² ):

Using a nano indenter (Mitsumi 1_I 〇 1\1 IX, Mimi 1\1 1-12 21 00), a nano-indentation test of the hardened material was performed. For the test piece, apply a photocurable composition to a thickness of 100 on a polyimide film with a thickness of 50. \¥02020/175196 29 卩(: 171? 2020 /005876

The hardened|cured body produced by making it harden|cure by irradiating an external line was used. And with the nano indenter, the maximum pushing force 〇 .1 1\1, the pushing speed 〇.

The Martens hardness of the cured product was measured under the condition of 01 1/1/sec. As a result, the average value of the Martens hardness measured at 5 points was ◯.

31\1/○ 1 ○ ^{12 If} less than or equal to 8 then 〇.

Greater than 〇.

If it is less than 0.51 \1/○ 1 ○ 1 ^{2 and} 1.01 \1/○ 1 ○ 1 ² or less, it is "○", 1.

A case in which more than 01 ² is set to "mouth".

[0081] Water vapor transmission rate (9/〇 1 ² .2411 "):

1 3 70208: 1 976, apply the resin composition at a thickness of 1 on the silicone release-treated polyester film, and

The wavelength of 1_ 0 is used for 200

The moisture permeability (water vapor transmission rate) of the cured product that was cured by irradiating ultraviolet rays for 1 hour was measured at a temperature of 40 ^° 0 and a relative humidity of 90% [¾ 1 ^to 1]. If the weight of the sample decreased during the measurement of moisture permeability, the decrease was corrected.

[0082] Volume resistivity (0 〇〇:

8 0 8 1 \ 1 Chome 3 multi digital multimeter

The volume resistivity was measured using a mitomi. Apply a photo-curable composition with a thickness of 100 on a silicone release-treated polyester film, and use 200!

Measure the cured product that has been cured by irradiating it with UV light for 15 seconds, and if the resistance value is above the upper limit of measurement, it is evaluated as "", and if it is the volume resistivity within the measurement range, the value is shown in the table. Described.

[0083] Warp:

To the polyimide film with a thickness of 501, apply the photolithographic composition to a thickness of 100

Using

It was cured by UV irradiation for 15 seconds. This cured product was cut out to 20 60, and when one end of the long side was pressed, the other end was not lifted, and was evaluated as "eight", and the one that was lifted was evaluated as "Mi". \¥02020/175196 30 卩 (: 171? 2020 /005876

[0084] Peeling force (1\1/○○:

1 3 <6852—2: 1 999 Measured by partially changing the 180 degree peel test method. Apply a photocurable composition to a thickness of 50! on a polyimide film with a thickness of 10!

Using

After curing by UV irradiation for 5 seconds, cut into a width of 26 and peel off at 300

丨_n, were measured peel strength (adhesive strength) by peeling at a peel angle of 1 80 °.

[0085] Local temperature and humidity resistance test:

Thickness on a polyimide film with a thickness of 50

Resin composition with a wavelength of 365

Using 200

Cut out for UV irradiation for 2 seconds. This is 85°○, 85%

After that, those with no floating or peeling were rated as "8", and those with floating or peeling were rated as "Mi".

[0086] Repair test:

By coating a resin composition on a polyimide film with a thickness of 50 to a thickness of 500 01 and a width of 20!○! and irradiating it with UV light at 200 mW/○ ² for 15 seconds using a 365 nm wavelength LED. Cured. When this cured product was peeled off from the polyimide film, it was rated "8" if it could be peeled visually without tearing, and "Mitsu" if it could not be peeled off.

[0087] Bending test (inside):

FIG. 4 is an explanatory diagram of the measurement method of the bending test (inside). Apply the photocurable composition to a thickness of 100 on a polyimide film 50 with a thickness of 500, and

Using

It was cured by irradiation with ultraviolet rays for 2 seconds to obtain a cured product 56. 26 of this cured product

Stick out a double-sided tape 54 with a thickness of 50 in the range of 26111111X5111111 on the edge of the cured product 56, and

A test piece was prepared by adhering it to the edge of the glass substrate 52 (3100). When the test piece was bent toward the non-adhesive tape side of the glass substrate 52 with load 509 so that the cured body 56 was on the inside ( \¥02020/175196 31 卩(: 171? 2020 /005876

31 02), and the protrusion width 40 protruding from the end of the glass substrate 12 (that is, the “protrusion length” protruding from the end of the glass substrate 12) was measured (31 04). Those with a protrusion width (extrusion length) of less than 400 were evaluated as “8”, those with a width of 400 or more and less than 500 were evaluated as “Mi”, and those of 500 ◯! or more were evaluated as “◯”.

[0088] Bending test (outside):

FIG. 5 is an explanatory diagram of the measurement method of the bending test (outside). Polyimide film 50 with a thickness of 500 is coated with a photocurable composition to a thickness of 100 and cured by irradiating it with ultraviolet light at 200 mW/cm ² for 15 seconds using a 365 nm wavelength LED. To obtain a cured product 56. 26 of this cured product

A double-sided tape 54 having a thickness of 50 〇! was attached to the end of the polyimide film 50 in the range of 26111111X5111111, and was attached to the end of the glass substrate 12 having a thickness of 10!! ). When the polyimide film 50 was placed on the inside of the test piece so that it was folded toward the non-adhesive tape side of the glass substrate 12 with a load 509 (3202), the “extrusion” of the glass substrate 12 Length") was measured (3204). Projection width 40 (A projecting length of less than 400 was evaluated as “8”, 400 ◯! or more and 500 〇! Insufficient was rated as “Mi”, and 500 or more was rated as “○”.

[0089] Flex resistance test:

The flex resistance test will be described with reference to FIGS. 6 and 7. As shown in Fig. 6, a polyimide film 50 with a thickness of 50 is

The photo-curable composition is applied so that

It was cured by irradiating it with ultraviolet rays for 15 seconds to obtain a cured product 56. Next, as shown in FIG. 7, the hardened material 56 was cut into 2001111X 1 0001111, and a weight of 11 <9 was attached to one end of the cut test piece. A 20- ^degree bending test was performed by inserting 20 from the end opposite to the weight. That is, at a bending angle of 180 ^° and a bending half-diameter of 100 ^° !○! or less, after bending the cured body 56 so that it is on the inside (left side of Fig. 7), the cured body 56 is on the outside. Bend it in the direction (right side of Fig. 7) \¥0 2020/175 196 32 卩 (: 171? 2020 /005876

One cycle was set, and the bent portion after 100 cycles was visually observed. The criteria for evaluation are as follows.

Eight: No cracks and no peeling.

Minami: There is no crack and there is peeling.

0: There are cracks and no peeling.

0: There are cracks and peeling.

[0090] Light transmittance (%):

For each sample, prepare a pair of glass plates, apply the photo-curable composition to one glass plate, and sandwich it with the other glass plate.

After curing, a test piece was prepared in which the cured product was sandwiched between a pair of glass plates. The reason why the test piece is sandwiched between glass plates is that diffuse reflection on the surface of the cured body affects the transmittance. Then, with respect to each test piece, the parallel light transmittance (light transmittance) at a wavelength of 550 n°! was measured using an ultraviolet-visible spectrophotometer (“11 — 1600” manufactured by Shimadzu Corporation).

[0091] Insulation reliability test:

Wiring spacing on glass epoxy board 0.3 1 8

It has copper wiring.” 丨32 The resin composition is applied to a comb-shaped substrate with a thickness of 100, and 1-M0 with a wavelength of 3 6 5 n is used.

Then, a test piece was prepared by curing. A voltage of 50 V was applied to the substrate for 120 hours in an environment of 85 °, 85% [¾ 1 ^to 1].

In all of the above-mentioned tests, the “thickness” of the photocurable composition means the thickness after curing.

[0093] <Analysis of test results>

[0094] Fig. 8 shows a graph plotting the Young's modulus on the horizontal axis and the peeling force on the vertical axis for each of Samples 1 to 29 and plotting the relationship between the Young's modulus and the peeling force. Considering the results of the bending test (inside), bending test (outside), and bending resistance test, the peeling force of the cured product of the photocurable composition or the elastic protective member is as follows from the graph of Fig. 8. 1) It was found that there is a relation of formula. \¥02020/175196 33 卩(: 171? 2020/005876

>100 x 4 (Min) +250 (1)

In the formula,: Peeling force (1\1/〇〇, Mitsu: Young's modulus

[0095] Since the peeling force of the elastic protection member has the relationship of the above formula (1), when the flexible substrate is bent from the end of the rigid substrate, the protection member is more rigid than the conventional one. Also, the bending radius of the flexible substrate can be reduced without peeling off from the flexible substrate. As a result, the protrusion width of the bent portion of the flexible substrate protruding outward from the end portion of the rigid substrate can be made smaller than that of the conventional one, and excellent in durability.

[0096] In addition, regarding Samples 1 to 29, a graph plotting the Young's modulus on the horizontal axis and the peeling force on the vertical axis and plotting the relationship between the Young's modulus and the peeling force is shown in FIG. Taking the results of the repair test into consideration, it was found from the graph of FIG. 8 that the peeling force of the cured product of the photocurable composition has the relationship of the following formula (2).

<100 X 4 (Mimi) + 760 (2)

In the formula,: Peeling force

Mami: Young's modulus

[0097] The cured product obtained by curing the photocurable composition is a rigid substrate because the peeling force of the cured product of the photocurable composition has the relationship of the above formula (2). Also, by not sticking to the flexible substrate more strongly than necessary, the durability of the electronic substrate against deformation of the flexible substrate can be enhanced while it can be peeled off from the base material and has excellent repairability.

Further, for Samples 1 to 29, a graph plotting the Young's modulus on the horizontal axis and the peeling force on the vertical axis and plotting the relationship between the Young's modulus and the peeling force is shown in FIG. Taking into account the results of the bending test (inside), bending test (outside) and bending resistance test, the graph of Fig. 9 shows that the cured product of the photocurable composition has a Young's modulus

Is particularly preferable in the range of 250 £ £800, and Young's modulus (IV! 3) is 0.3 <M £ 1.0 and the peeling force is

Is more preferable, and the Young's modulus is 0.01 £ £ £ 0.3 and the peeling coefficient is

The range 8 with 80 £ £550 is more preferable. \¥0 2020/175 196 34 卩 (: 171? 2020 /005876

won. When an elastic protection member with the property of the above range <3 is used, the stress for reducing the bending radius becomes large, but it is high strength and resistant to rubbing, and is suitable for large substrates and applications where shock such as vibration is applied. Is. On the other hand, when the elastic protective layer material having the properties within the above range is used, the bending radius can be reduced with a weak stress. Therefore, the load on the flexible substrate or the rigid substrate is small, and it is suitable for application to, for example, a glass substrate or a thin substrate that is easily damaged. For this reason, it is preferable to have a range of properties, especially when it is desired to reduce the size and size of the frame together. On the other hand, it has been found that Umizumi is an elastic protective member having intermediate properties and is preferable in that it is easy to use in a wide range of applications. The Young's modulus could not be measured because the test piece of Sample 25 was hard and brittle. In addition, the test pieces of Samples 23 and 27 were torn into pieces during curing, and the peeling force could not be measured.

[0099] Viscosity:

Looking at the samples with a thermoplastic elastomer concentration of 15% by mass or less, the sum of monofunctional highly polar monomers and polyfunctional monomers was 12.7 5% by mass or more. Samples 13, 18, 20, 20 In 6, the viscosity is slightly higher. On the other hand, it can be seen that the viscosity of the remaining samples is kept low.

[0100] Martens hardness

:

Looking at the relationship between the Martens hardness and the peeling force for Samples 1 to 29, the results of the bending test (inside), bending test (outside), and bending resistance test were taken into consideration and As for the cured product, the sample with a Martens hardness of "8" has a small value of 100% elongation tensile stress in addition to flexibility, and it has excellent extensibility. It was found that it is preferable even if it is provided in the point that it can be bent with a small stress and the force (repulsive force) to return to the original position after bending can be reduced.

[0101] The Martens hardness is 〇.

At that time, the peeling power (1\1/○○ was in the range of 80 <＜5 56. In addition, the Martens hardness was ○ 0.3.

Greater than 0.5

When it was below, the peeling force (1\1/○○ was in the range of 200<＜896. \¥02020/175196 35 卩 (: 171? 2020 /005876

[0102] Warp:

Warpage was observed for Samples 26 and 28. It can be seen that Samples 26 and 28 have a higher content of polyfunctional monomers and polyfunctional polymers and a higher Young's modulus of 3 IV! 8 or more than the other samples.

[0103] Light transmittance (%):

The light transmittance of Sample 7, which was 3%3 with the mass ratio of the soft segment of 87% by mass, was 95%. On the other hand, in the remaining samples, the transmittance was less than 86%, and the cured product was opaque, resulting in poor light transmission.

[0104] Insulation reliability test:

No short circuit of copper wiring was observed in all the photocurable compositions according to one embodiment of the present invention. On the other hand, in Sample 29, the surface of the copper wiring turned brown.

Explanation of symbols

[0105] 10 Electronic board

1 2 Rigid board

1 2 ₃ Polarizer

1 2 匕 1st glass substrate with transparent electrode

1 2 0 Liquid crystal layer

1 2 2nd glass substrate with transparent electrode

1 26 Polarizer

1 2 Dry back light unit

1 3 Sealant

1 4 Flexible board

1 5 Anisotropic conductive film

1 6 Bent section

203, 20 Elastic protection member

30 ₃ , 30 border area

40 Projection width

Claims

\\0 2020/175 196 36 卩(: 171? 2020/005876 Claims

[Claim 1] An electronic board comprising: a rigid board; and a flexible board extending from an end portion of the rigid board and connected in a conductive manner,

An elastic protection member is provided on at least one surface of the bent portion of the flexible substrate from the end of the flexible substrate,

When the flexible board is protruded from the end of the rigid board and bent toward one surface side of the rigid board, the bending part of the flexible board is protruded from the end of the rigid board. An electronic substrate having a protrusion width of 100 to 4001.

[Claim 2] The elastic protective member has a Martens hardness measured by a nanoindentation test of 0.1 to 〇.

Electronic board described in.

[Claim 3] The electronic substrate according to claim 1, wherein the peeling force of the elastic protection member has a relationship represented by the following formula (1).

>100 x 4 (Min) +250 (1)

In the formula,: Peeling force

Mami: Young's modulus

[Claim 4] The flexible substrate is a resin film having a thickness of 15 to 200,

The electronic board according to claim 1, wherein a wiring body is provided on an inner surface of the flexible board when the flexible board is bent.

[Claim 5] A photocurable composition for forming an elastic protective layer by applying light to an electronic substrate and then curing the composition,

Monofunctional alicyclic (meth)acrylic acid ester monomer, monofunctional aliphatic (meth)acrylic acid ester monomer, monofunctional highly polar monomer, \¥02020/175196 37 卩 (: 171? 2020 /005876

Including a thermoplastic elastomer and a radical polymerization initiator,

Viscosity when uncured is 10 to 5000

The hardness of the cured product after curing is in the range of 3 and the hardness measured by the nanoindentation test is from 0.01 to 0.

The photo-curable composition is characterized in that

6. The photocurable composition according to claim 5, wherein the peeling force of the cured product of the photocurable composition after curing exhibits the relationship of the following formula (1).

>100 x 4 (Min) +250 (1)

In the formula,: Peeling force

Mami: Young's modulus

7. The photocurable composition according to claim 5, wherein the peeling force of the cured product of the photocurable composition after curing exhibits the relationship of the following formula (2).

<100 X 4 (Mimi) + 760 (2)

: Peel force

º: Young's modulus (IV! 3)

[8] An electronic substrate obtained by applying the photocurable composition according to any one of [5] to [7] to a boundary region between the rigid substrate and the flexible substrate.