JP7391469B2 - UV-curable silicone composition and articles using the same - Google Patents

Description

The present invention relates to ultraviolet curable silicone compositions and articles using the compositions.

In recent years, flat panel type image display devices such as liquid crystal, plasma, and organic EL have been attracting attention. In addition, improvements in productivity and reduction in stockyards are concerns in all industrial fields including general electrical parts. The situation is similar not only in Japan but also at overseas production bases, and countermeasures are urgently needed.

Under these circumstances, from the viewpoint of productivity, compositions that can be cured with electron beams or ultraviolet rays have been provided to date. Compositions that cure with ultraviolet light can be cured in a short period of time to a point where light can pass through the surface, making them very effective. However, the surface is susceptible to curing inhibition by oxygen, resulting in problems such as the surface not curing sufficiently. There is. Additionally, there are also problems such as the areas that are not irradiated with light are not cured or are insufficiently cured. Therefore, consideration must be given to various production facilities and the environment.

On the other hand, heat-curable compositions are also used for such purposes. Since it can be cured under predetermined temperature conditions, it is widely used for heatable parts. Further, curing is possible in all ranges by heating. However, heating equipment, cooling equipment, and time are required, so it is not as time-saving as ultraviolet curing.

Furthermore, compositions that can be cured by moisture (moisture) in the air are also provided. Because it is cured by moisture in the air, it takes a considerable amount of time to harden to the inside. Furthermore, when other component systems are used, there is a concern that the manufacturing process, such as measuring and mixing them, will be complicated.

Under such circumstances, several compositions have been proposed in order to improve the concerns regarding ultraviolet curable compositions. Patent Document 1 discloses an ultraviolet curable liquid silicone rubber coating agent composition that uses fine silica powder to impart strength to the resulting cured product. Further, Patent Document 2 discloses an ultraviolet curable composition using a filler whose surface has been treated with a compound having an ultraviolet ray-reactive group in order to improve the fillability of the filler. Patent Document 3 discloses a silicone composition that has a high modulus (Young's modulus) when cured and has such a low modulus that peeling and distortion occur during use.

JP 2018-3194 Publication Japanese Patent Application Publication No. 2005-89672 JP 2017-110137 Publication

However, in the ultraviolet curable compositions of Patent Documents 1 to 3, the viscosity increases significantly during storage, resulting in a problem in long-term storage stability.

An object of the present invention is to provide an ultraviolet curable silicone composition that has excellent long-term storage stability.

The present inventors have found that the above-mentioned problems can be solved by using silica surface-treated with a polyorganosiloxane having two or more alkoxysilyl groups in the molecule, and have completed the present invention.

〔式（１）中、
Ｒ^１は、独立して、Ｃ１～Ｃ９アルキル基、Ｃ６～Ｃ１２アリール基、１～３個の（メタ）アクリロイル基及び／若しくは（メタ）アクリロイルオキシ基で置換されているＣ１～Ｃ９アルキル基、（メタ）アクリロイル基、（メタ）アクリロイルオキシ基、１～３個のＣ１～Ｃ９アルコキシ基で置換されたＣ１～Ｃ９アルキル基、又はＣ１～９アルコキシ基であり、
少なくとも１個のＲは、１～３個の（メタ）アクリロイル基及び／若しくは（メタ）アクリロイルオキシ基で置換されているＣ１～Ｃ９アルキル基、（メタ）アクリロイル基、又は（メタ）アクリロイルオキシ基であり、
Ｌ１は、２３℃での粘度を０．０１～１００Ｐａ・ｓとする値である〕
で示されるオルガノポリシロキサンである、[１］の紫外線硬化性シリコーン樹脂組成物。
［３］成分（Ｂ）が、下記式（２）：

〔式中、
Ｌ３は、２３℃での粘度を０．０１～１００Ｐａ・ｓの範囲とする数であり、
Ｒ^４は、独立して、Ｃ１～Ｃ６アルキル基又はＣ６～Ｃ１２アリール基であり、
Ｒ^５は、独立して、１～３個のＣ１～Ｃ９アルコキシ基で置換されているＣ１～Ｃ９アルキル基であるか、又はＣ１～９アルコキシ基であり、
Ｒ^６は、独立して、Ｃ１～Ｃ６アルキル基又はＣ６～Ｃ１２アリール基であり、
ｔは、１、２又は３である〕
で示されるポリオルガノシロキサンで表面処理されたシリカである、[１］又は[２］の紫外線硬化性シリコーン樹脂組成物。
[４］成分（Ａ）が湿気反応性基を有し、組成物が更に（Ｄ）硬化触媒を含む、[１］～[３］のいずれかの紫外線硬化性シリコーン組成物。
[５］更に、（Ｅ）架橋剤を含む、[１］～[４］のいずれかの硬化性シリコーン組成物。
[６］[１］～[５］のいずれかの紫外線硬化性シリコーン組成物からなる、画像表示装置用接着剤。
[７］[６］の画像表示装置用接着剤を用いて、画像表示部と保護部とが封止された、画像表示装置。 The present invention relates to the following [1] to [7].
[1] (A) polyorganosiloxane having two or more photoreactive groups in the molecule,
An ultraviolet curable silicone composition comprising (B) silica surface-treated with a polyorganosiloxane having two or more alkoxysilyl groups in the molecule, and (C) a photoreaction initiator.
[2] Component (A) is represented by the following formula (1):

[In formula (1),
R ¹ is independently a C1 to C9 alkyl group, a C6 to C12 aryl group, a C1 to C9 alkyl group substituted with 1 to 3 (meth)acryloyl groups and/or (meth)acryloyloxy groups, (meth)acryloyl group, (meth)acryloyloxy group, C1-C9 alkyl group substituted with 1-3 C1-C9 alkoxy groups, or C1-9 alkoxy group,
At least one R is a C1 to C9 alkyl group, (meth)acryloyl group, or (meth)acryloyloxy group substituted with 1 to 3 (meth)acryloyl groups and/or (meth)acryloyloxy groups. and
L1 is a value that makes the viscosity at 23°C 0.01 to 100 Pa·s]
The ultraviolet curable silicone resin composition of [1], which is an organopolysiloxane represented by:
[3] Component (B) is the following formula (2):

[During the ceremony,
L3 is a number that makes the viscosity at 23 ° C. range from 0.01 to 100 Pa s,
R ⁴ is independently a C1-C6 alkyl group or a C6-C12 aryl group,
R ⁵ is independently a C1-C9 alkyl group substituted with 1 to 3 C1-C9 alkoxy groups, or a C1-9 alkoxy group;
R ⁶ is independently a C1-C6 alkyl group or a C6-C12 aryl group,
t is 1, 2 or 3]
The ultraviolet curable silicone resin composition of [1] or [2], which is silica surface-treated with a polyorganosiloxane represented by:
[4] The ultraviolet curable silicone composition according to any one of [1] to [3], wherein component (A) has a moisture-reactive group and the composition further contains (D) a curing catalyst.
[5] The curable silicone composition according to any one of [1] to [4], further comprising (E) a crosslinking agent.
[6] An adhesive for image display devices comprising the ultraviolet curable silicone composition according to any one of [1] to [5].
[7] An image display device in which an image display section and a protection section are sealed using the adhesive for image display devices according to [6].

According to the present invention, an ultraviolet curable silicone composition having excellent long-term storage stability is provided.

[Definition of terms]
In this specification, specific examples and preferred ranges of the group are as follows.
Examples of the monovalent hydrocarbon group include a C1-C9 alkyl group, a C3-C20 cycloalkyl group, a C6-C20 aryl group, an aralkyl group, and a C2-C9 alkenyl group. Examples of the monovalent hydrocarbon group having no aliphatic unsaturated bond include the above-mentioned monovalent hydrocarbon groups other than alkenyl groups. Here, the C1-C9 alkyl group means an alkyl group having 1 to 9 carbon atoms. The same applies to other groups.
The C1 to C9 alkyl group is a straight chain or branched group, and examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, and a nonyl group. Further, the C1-C9 alkyl group is preferably a C1-C6 alkyl group, more preferably a C1-C4 alkyl group, and particularly preferably a methyl group.
The C3-C20 cycloalkyl group is a monocyclic or polycyclic group, and examples thereof include a cyclopentyl group and a cyclohexyl group.
The C6-C20 aryl group is an aromatic group containing a monocyclic or polycyclic group, and examples thereof include a phenyl group and a naphthyl group. Further, the C6-C20 aryl group is preferably a C6-C12 aryl group, and particularly preferably a phenyl group or a naphthyl group.
The aralkyl group is a C1 to C9 alkyl group substituted with a C6 to C20 aryl group, and examples thereof include a 2-phenylethyl group and a 2-phenylpropyl group.
The C2-C9 alkenyl group is a straight-chain or branched group, and examples include a vinyl group, an allyl group, a 3-butenyl group, and a 5-hexenyl group. The C2-C9 alkenyl group is preferably a C2-C6 alkenyl group, particularly preferably a vinyl group or an allyl group.
The alkylene group is a linear or branched group having 1 to 18 carbon atoms, and includes a methylene group, an ethylene group, a trimethylene group, a 2-methylethylene group, a tetramethylene group, and the like. Further, the C1 to C9 alkylene group is preferably a C1 to C6 alkylene group, more preferably a C1 to C5 alkylene group, and particularly preferably an ethylene group, a trimethylene group, or a tetramethylene group.
The alkenyl group, alkyl group, cycloalkyl group, aryl group, aralkyl group, and alkylene group may be substituted with a halogen atom such as chlorine, fluorine, or bromine; or a cyano group. Examples of the group substituted with a halogen atom include a chloromethyl group, a chlorophenyl group, and a 3,3,3-trifluoropropyl group. Examples of the group substituted with a cyano group include a 2-cyanoethyl group.
The C1 to C9 alkoxy group is a straight chain or branched group, and examples thereof include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and the like. Further, the C1 to C9 alkoxy group is preferably a C1 to C4 alkoxy group, more preferably a methoxy group or an ethoxy group, and particularly preferably a methoxy group.

In this specification, "(A) polyorganosiloxane having two or more photoreactive groups in the molecule" is also referred to as "component (A)." The same applies to "(C) photoreaction initiator" and the like.

[Ultraviolet curable silicone composition]
The ultraviolet curable silicone composition is made of silica surface-treated with (A) a polyorganosiloxane having two or more photoreactive groups in the molecule, and (B) a polyorganosiloxane having two or more alkoxysilyl groups in the molecule. , and (C) a photoreaction initiator.

Since the ultraviolet curable silicone composition has excellent long-term storage stability, thickening (increase in viscosity) during a storage period of 3 to 30 days, for example, can be suppressed.

<(A) Polyorganosiloxane having two or more photoreactive groups in the molecule>
Component (A) is a polyorganosiloxane having two or more photoreactive groups in its molecule. Since the ultraviolet curable silicone composition contains component (A), the silicone composition can be made into an ultraviolet curable composition.

(molecular structure)
Component (A) is a silicone having a siloxane structure (-Si-O-Si-) as its main skeleton. The molecular structure of component (A) can be linear or branched. Component (A) is preferably linear because it is easier to control the physical properties of the cured product.

(Photoreactive group)
As used herein, the term "photoreactive group" refers to a functional group that causes the curing reaction of silicone to proceed with light, such as ultraviolet light. Examples of the photoreactive group include alkenyl groups such as vinyl groups and allyl groups, (meth)acryloyl groups, (meth)acryloyloxy groups, and epoxy groups. The photoreactive group is preferably a (meth)acryloyl group or a (meth)acryloyloxy group.

The photoreactive group may be directly bonded to the silicon atom of component (A), or may be bonded to the silicon atom of component (A) as a group having a photoreactive group (but does not contain a silicon atom). You may do so. Hereinafter, a group having a photoreactive group and a photoreactive group may be collectively referred to as a "photoreactive group, etc.".

Examples of the group having a photoreactive group include C1 to C9 alkyl groups substituted with 1 to 3 (meth)acryloyl groups and/or (meth)acryloyloxy groups. Here, "substituted with 1 to 3 (meth)acryloyl groups and/or (meth)acryloyloxy groups" refers to the (meth)acryloyl and (meth)acryloyloxy groups present as substituents. This means that the total number is 1 to 3. In addition, when the group having a photoreactive group is a C1 to C9 alkyl group substituted with two (meth)acryloyl groups and/or (meth)acryloyloxy groups, the photoreactivity based on the alkyl group The number of groups is two.

（式中、Ｒ^ａは、水素原子又はメチル基であり、Ｑ^１は、Ｃ１～Ｃ９アルキレン基である） The group having a photoreactive group is preferably a group represented by the following formula (a).

(In the formula, R ^a is a hydrogen atom or a methyl group, and Q ¹ is a C1 to C9 alkylene group)

R ^a is preferably a methyl group from the viewpoint of ease of synthesis and storage stability.

(Number of photoreactive groups)
The number of photoreactive groups in component (A) is two or more in the molecule. In terms of the efficiency of the curing reaction of the ultraviolet curable silicone composition and the hardness of the cured product obtained, the number of photoreactive groups in component (A) is preferably 2 to 100 in the molecule, It is more preferable that the number is 2 to 50, particularly preferably 2 to 20 in the molecule. Component (A) can have the same or different types of photoreactive groups in the same molecule, but preferably have the same type of photoreactive groups.

(Location of photoreactive group)
The photoreactive group etc. may be bonded to the silicon atom at the end or in the middle of the siloxane structure of component (A), or may be bonded to both. Furthermore, the photoreactive groups, etc. may be bonded to the same silicon atom in component (A), or may be bonded to different silicon atoms, but the photoreactive groups, etc. may be bonded to different silicon atoms. It is preferable that Here, the terminal silicon atom of the siloxane structure means the silicon atom of the triorganosiloxane unit. Moreover, the silicon atom in the middle of the siloxane structure means the silicon atom of a diorganosiloxane unit or a monoorganosiloxane unit.

(further groups)
Additional groups other than the photoreactive group that component (A) has include moisture-reactive groups and monovalent organic groups other than the photoreactive groups and moisture-reactive groups.

≪Moisture-reactive group≫
As used herein, the term "moisture-reactive group" refers to a functional group that causes the curing reaction of silicone to proceed due to moisture, that is, moisture. In addition, when component (A) has a moisture-reactive group, the composition has moisture curability, thereby increasing the surface curability of the cured product.

Moisture-reactive groups include alkoxy groups. The moisture-reactive group is preferably a C1-9 alkoxy group, particularly preferably a methoxy group or an ethoxy group. Although component (A) may have different types of moisture-reactive groups in the same molecule, it is preferable that they have the same type of moisture-reactive groups because preparation becomes easier.

The moisture-reactive group may be directly bonded to the silicon atom in component (A), and the silicon atom in component (A) can be used as a group having a moisture-reactive group (but does not contain a silicon atom). May be combined with Here, examples of the group having a moisture-reactive group include a C1-C9 alkyl group substituted with 1 to 3 C1-C9 alkoxy groups.

≪Monovalent organic group other than photoreactive group and moisture-reactive group≫
Monovalent organic groups other than photoreactive groups and moisture-reactive groups include monovalent hydrocarbon groups other than alkenyl groups. The monovalent organic group other than the photoreactive group and the moisture-reactive group is preferably an alkyl group, and a methyl group is preferable, from the viewpoint of efficient curing reaction and ease of synthesis. It is particularly preferable. Further, from an optical viewpoint and a viewpoint of achieving a high refractive index, an aryl group, particularly a phenyl group, may be introduced into at least a part of the functional groups possessed by the silicon atoms of the siloxane structure.

From the viewpoint of workability, the viscosity of component (A) is preferably in the range of 0.01 to 100 Pa·s, more preferably in the range of 0.1 to 50 Pa·s, and more preferably in the range of 0.3 to 30 Pa·s. It is more preferably in the range of ・s, and particularly preferably in the range of 0.5 to 20 Pa·s. Furthermore, the viscosity of the component (A) as a whole may be adjusted by using a combination of two or more types of components (A).

In this specification, "viscosity" is measured using a rotational viscometer (Vismetron VDA-L) (manufactured by Shibaura System Co., Ltd.). The value is measured at 23°C using 2 to 4 rotors at 30 rpm or 60 rpm.

〔式（１）中、
Ｒ^１は、独立して、Ｃ１～Ｃ９アルキル基、Ｃ６～Ｃ２０アリール基、１～３個の（メタ）アクリロイル基及び／若しくは（メタ）アクリロイルオキシ基で置換されているＣ１～Ｃ９アルキル基、（メタ）アクリロイル基、（メタ）アクリロイルオキシ基、１～３個のＣ１～Ｃ９アルコキシ基で置換されたＣ１～Ｃ９アルキル基、又はＣ１～９アルコキシ基であり、
少なくとも２個のＲ^１は、１～３個の（メタ）アクリロイル基及び／若しくは（メタ）アクリロイルオキシ基で置換されているＣ１～Ｃ９アルキル基、（メタ）アクリロイル基、又は（メタ）アクリロイルオキシ基であり、
Ｌ１は、２３℃での粘度を０．０１～１００Ｐａ・ｓとする値である〕
で示されるポリオルガノシロキサンであることが好ましい。 (Preferred embodiment)
Linear (A) is (A1) formula (1):

[In formula (1),
R ¹ is independently a C1 to C9 alkyl group, a C6 to C20 aryl group, a C1 to C9 alkyl group substituted with 1 to 3 (meth)acryloyl groups and/or (meth)acryloyloxy groups, (meth)acryloyl group, (meth)acryloyloxy group, C1-C9 alkyl group substituted with 1-3 C1-C9 alkoxy groups, or C1-9 alkoxy group,
At least two R ^1s are C1 to C9 alkyl groups, (meth)acryloyl groups, or (meth)acryloyloxy groups substituted with 1 to 3 (meth)acryloyl groups and/or (meth)acryloyloxy groups. is the basis,
L1 is a value that makes the viscosity at 23°C 0.01 to 100 Pa·s]
Preferably, it is a polyorganosiloxane represented by:

In formula (1), the total number of photoreactive groups, etc. is preferably 2 to 10, and preferably 2 to 5, from the viewpoint of ease of synthesis, reactivity, and properties obtained. is particularly preferred.

R ¹ , which is a photoreactive group, may be bonded to any silicon atom in formula (1). R ¹ , which is a photoreactive group, is preferably bonded to a terminal silicon atom. From the point of view of the flexibility of the resulting cured product, it is more preferable that it is bonded to the silicon atoms at both ends, it is still more preferable that it is bonded only to the silicon atoms at both ends, and only to the silicon atoms at both ends. It is particularly preferable that one R ¹ , such as a photoreactive group, is bonded to each of them.

〔式中、
Ｒ^ｂは、独立して、水素原子又はメチル基であり、
Ｑ^２は、独立して、Ｃ１～Ｃ９アルキレン基であり、
Ｒ^２は、独立して、Ｃ１～Ｃ９アルキル基又はＣ１～Ｃ９アルコキシ基であり、
Ｒ^３は、独立して、Ｃ１～Ｃ９アルキル基又はＣ６～Ｃ２０アリール基であり、
Ｌ２は、２３℃での粘度を０．０１～１００Ｐａ・ｓとする値である）
で示されるポリオルガノシロキサンが特に好ましい。 In addition, from the viewpoint of obtaining good curability, component (A) is expressed by formula (A1') (1'):

[During the ceremony,
R ^b is independently a hydrogen atom or a methyl group,
Q ² is independently a C1-C9 alkylene group,
R ² is independently a C1-C9 alkyl group or a C1-C9 alkoxy group,
R ³ is independently a C1-C9 alkyl group or a C6-C20 aryl group,
L2 is a value that makes the viscosity at 23°C 0.01 to 100 Pa・s)
Particularly preferred are the polyorganosiloxanes shown below.

R ^b is preferably a methyl group from the viewpoint of ease of synthesis and storage stability. Furthermore, it is particularly preferred that all R ^b 's are methyl groups.
Preferably, all Q ² are C1-C4 alkylene groups, particularly preferably all Q ² are ethylene or trimethylene groups.

Since the ultraviolet curable silicone composition has moisture curability and thereby increases the surface curability of the cured product, it is preferable that at least one R ² is a C1 to C9 alkoxy group, and all R ² is particularly preferably a C1-C9 alkoxy group.

R ³ is preferably a methyl group from the viewpoint of ease of synthesis and economics, and is preferably a phenyl group from the optical viewpoint and from the viewpoint of obtaining a high refractive index. Further, all R ³ are more preferably C1 to C9 alkyl groups, particularly preferably methyl groups.

（式中、
Ｒ^ｃは、独立して、水素原子又はメチル基であり、
Ｑ^３は、独立して、Ｃ１～Ｃ９アルキレン基であり、
Ｒ^１１は、独立して、Ｃ１～Ｃ９アルキル基、Ｃ６～Ｃ２０アリール基又はＣ１～Ｃ９アルコキシ基であり、
Ｒ^１２は、独立して、Ｃ１～Ｃ９アルキル基、Ｃ６～Ｃ２０アリール基又はＣ１～Ｃ９アルコキシ基であり、
Ｒ^１３は、独立して、Ｃ１～Ｃ９アルキル基、Ｃ６～Ｃ２０アリール基又はＣ１～Ｃ９アルコキシ基であり、
ｐは、１～１０であり、
ｑは、０～１０であり、
ｒは、０～１００であり、
ｓは、０～１０であり、
ｐ／（ｐ＋ｑ＋ｒ＋ｓ）≧０．０２である）
で示される、分岐状ポリオルガノシロキサンが好ましい。 As the branched (A), (A2) the following average formula:

(In the formula,
R ^c is independently a hydrogen atom or a methyl group,
Q ³ is independently a C1-C9 alkylene group,
R ¹¹ is independently a C1-C9 alkyl group, a C6-C20 aryl group, or a C1-C9 alkoxy group,
R ¹² is independently a C1-C9 alkyl group, a C6-C20 aryl group, or a C1-C9 alkoxy group,
R ¹³ is independently a C1-C9 alkyl group, a C6-C20 aryl group, or a C1-C9 alkoxy group,
p is 1 to 10,
q is 0 to 10,
r is 0 to 100,
s is 0 to 10,
p/(p+q+r+s)≧0.02)
A branched polyorganosiloxane represented by is preferred.

R ^c is preferably a methyl group from the viewpoint of ease of synthesis and storage stability.

Since the ultraviolet curable silicone composition has moisture curability, which increases the surface curability of the cured product, at least one of R ¹¹ , R ¹² and R ¹³ is preferably a C1 to C9 alkoxy group. Preferably, at least two of R ¹¹ , R ¹² and R ¹³ are particularly preferably C1-C9 alkoxy groups.

R ¹¹ other than the C1 to C9 alkoxy group is preferably a methyl group from the viewpoint of ease of synthesis and economics, and is preferably a phenyl group from the optical viewpoint and from the viewpoint of obtaining a high refractive index. Further, R ¹² and R ¹³ other than the C1 to C9 alkoxy group are as described above for R ¹¹ including the preferred range.

p is preferably 1-8, particularly preferably 1-5.
q is preferably from 0 to 8, particularly preferably from 0 to 5.
r is preferably 1-80, particularly preferably 2-70.
s is preferably 0-8, particularly preferably 0-6.
From the viewpoint of obtaining good curability, it is preferable that p/(p+q+r+s)≧0.06, and it is particularly preferable that p/(p+q+r+s)≧0.10.

Examples of (A2) include branched polyorganosiloxanes represented by the following average formula. However, if they exist in the average formula, q, r, and s are assumed to be non-zero. Moreover, "Ph" represents a phenyl group.
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{CH ₃ SiO _3/2 }q{(CH ₃ ) ₂ SiO}r{(CH ₃ ) ₃ SiO _1/2 }s
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{(CH ₃ ) ₂ SiO}r{(CH ₃ ) ₃ SiO _1/2 }s
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{CH ₃ SiO _3/2 }q{(CH ₃ ) ₃ SiO _1/2 }s
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{CH ₃ SiO _3/2 }q{(CH ₃ ) ₂ SiO}r
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{(CH ₃ ) ₃ SiO _1/2 }s
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{CH ₃ SiO _3/2 }q
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{(CH ₃ ) ₂ SiO}r
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{Ph ₃ SiO _3/2 }q{(CH ₃ ) ₂ SiO}r{(CH ₃ ) ₃ SiO _1/2 }s
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{Ph ₃ SiO _3/2 }q{(CH ₃ ) ₂ SiO}r
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{Ph ₃ SiO _3/2 }q{(CH ₃ ) ₃ SiO _1/2 }s
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{Ph ₃ SiO _3/2 }q
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{CH ₃ SiO _3/2 }q{Ph ₂ SiO}r{(CH ₃ ) ₃ SiO _1/2 }s
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{CH ₃ SiO _3/2 }q{Ph ₂ SiO}r
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{Ph ₂ SiO}r{(CH ₃ ) ₃ SiO _1/2 }s
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{Ph ₂ SiO}r
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{CH ₃ SiO _3/2 }q{(CH ₃ ) ₂ SiO}r{Ph ₃ SiO _1/2 }s
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{CH ₃ SiO _3/2 }q{Ph ₃ SiO _1/2 }s
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{(CH ₃ ) ₂ SiO}r{Ph ₃ SiO _1/2 }s
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{Ph ₃ SiO _1/2 }s
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{PhSiO _3/2 }q{Ph ₂ SiO}r{(CH ₃ ) ₃ SiO _{1 /2} }s
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{PhSiO _3/2 }q{Ph ₂ SiO}r
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{PhSiO _3/2 }q{(CH ₃ ) ₂ SiO}r{Ph ₃ SiO _{1 /2} }s
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{PhSiO _3/2 }q{Ph ₃ SiO _1/2 }s
{CH ₂ =C(CH ₃ )-C(=O)-O-(CH ₂ ) ₃ SiO _3/2 }p{PhSiO _3/2 }q{Ph ₂ SiO}r{Ph ₃ SiO _1/2 } s

The weight average molecular weight of component (A2) is preferably 500 to 100,000, more preferably 1,000 to 80,000, particularly preferably 1,000 to 60,000. In this specification, "weight average molecular weight" is a value determined by gel permeation chromatography (GPC) using polystyrene as a calibration curve.

Component (A) may be used alone or in combination of two or more. In the composition, component (A) preferably consists of only component (A1), particularly preferably only component (A1'). Furthermore, from the viewpoint of increasing curability, component (A) may be a combination of a linear polyorganosiloxane and a branched polyorganosiloxane.

<(B) Silica surface-treated with polyorganosiloxane having two or more alkoxysilyl groups in the molecule>
Component (B) is silica surface-treated with polyorganosiloxane having two or more alkoxysilyl groups in the molecule. When the composition contains component (B), the composition has excellent long-term storage stability. Component (B) is specifically a surface-treated silica obtained by surface-treating (b1) unsurface-treated silica with (b2) a polyorganosiloxane having two or more alkoxysilyl groups in the molecule. When component (b1) is surface-treated with component (b2), the amount of silanol groups present on the surface of component (b1) is reduced. This increases the long-term shelf life of the composition. Further, by treating with component (B), it is possible to obtain a composition with lower thixotropy than that generally treated with silane, silazane, etc.

((b1) Unsurface treated silica)
Component (b1) is unsurface-treated silica. Component (b1) is surface-treated with component (b2), which will be described later.

Examples of the unsurface-treated silica as component (b1) include wet-process silica such as precipitated silica, gel-process silica, and sol-process silica; and dry-process silica such as fumed silica. From the viewpoint of low water content, storage stability and surface treatment, the silica is preferably fumed silica.

In view of the excellent deep curability of the ultraviolet curable silicone composition, the BET specific surface area of component (b1) is preferably 50 to 500 m ² /g, more preferably 80 to 400 m ² /g, Particularly preferred is 100 to 300 m ² /g.

Commercially available products of component (b1) include Aerosil 300 (manufactured by Nippon Aerosil Co., Ltd.), Aerosil 200 (manufactured by Nippon Aerosil Co., Ltd.), Aerosil 130 (manufactured by Nippon Aerosil Co., Ltd.), and Rheosil QS-10 (manufactured by Tokuyama Co., Ltd.). etc.
Component (b1) may be used alone or in combination of two or more.

((b2) Polyorganosiloxane having two or more alkoxysilyl groups in the molecule)
Component (b2) is a polyorganosiloxane having two or more alkoxysilyl groups in its molecule. Component (b2) is a surface treatment agent for component (b1). That is, the alkoxysilyl group that component (b2) has is a hydrolyzable group, and the surface of component (b1) is treated by reacting with the silanol group present on the surface of component (b1).

≪Molecular structure≫
The molecular structure of component (b2) can be linear or branched. Component (b2) is preferably linear because it is easier to control the physical properties of the cured product.

≪Alkoxysilyl group≫
The alkoxysilyl group is a triorganosilyl group having one or more alkoxy groups that are hydrolyzable groups. Such alkoxysilyl groups include monoalkoxydiorganosilyl groups in which one C1 to C9 alkoxy group and two monovalent hydrocarbon groups are bonded to a silicon atom, and monoalkoxydiorganosilyl groups in which one C1 to C9 alkoxy group and two monovalent hydrocarbon groups are bonded to a silicon atom, Examples include a dialkoxymonoorganosilyl group in which a group and one monovalent hydrocarbon group are bonded, and a trialkoxysilyl group in which three C1 to C9 alkoxy groups are bonded to a silicon atom.

An alkoxysilyl group is a monoalkoxydialkylsilyl group in which one C1 to C9 alkoxy group and two C1 to C9 alkyl groups are bonded to a silicon atom, or a monoalkoxydialkylsilyl group in which one C1 to C9 alkoxy group and two C1 to C9 alkyl groups are bonded to a silicon atom, and a monoalkoxydialkylsilyl group in which one C1 to C9 alkoxy group and two C1 to C9 alkyl groups are bonded to a silicon atom, Preferably, it is a dialkoxymonoalkylsilyl group to which a valent C1-C9 alkyl group is bonded, or a trialkoxysilyl group to which three C1-C9 alkoxy groups are bonded to a silicon atom; Particularly preferred is an alkoxysilyl group.

The dialkoxymonoalkylsilyl group is preferably a dimethoxymethylsilyl group or a diethoxyethylsilyl group. Further, the trialkoxysilyl group is preferably a trimethoxysilyl group or a triethoxysilyl group.

In component (b2), the silicon atom of the alkoxysilyl group may be directly bonded to the siloxane chain of the polyorganosiloxane, or may be bonded to the siloxane chain of the polyorganosiloxane through a linking group such as an ester bond. good. Further, when the silicon atom of the alkoxysilyl group is directly bonded to the siloxane chain of the polyorganosiloxane, it is bonded to the polyorganosiloxane chain via the oxygen atom of the siloxane chain.

≪Number of alkoxysilyl groups≫
The number of alkoxysilyl groups in component (b2) is 2 or more in the molecule. In terms of the efficiency of the curing reaction of the ultraviolet curable silicone composition and the hardness of the cured product obtained, the number of alkoxysilyl groups in component (b2) is preferably 2 to 100 in the molecule. It is more preferable that the number is 2 to 50, and particularly preferably 2 to 5. Component (b2) can have the same or different types of alkoxysilyl groups in the same molecule, but preferably has the same type of alkoxysilyl groups. Further, the location of the alkoxysilyl group in component (b2) is arbitrary.

≪Further base≫
In component (b2), further groups other than the alkoxysilyl group bonded to the siloxane chain of the polyorganosiloxane include monovalent organic groups, preferably monovalent hydrocarbon groups, and C1 to C9 Particularly preferred is an alkyl group. Furthermore, component (b2) may or may not have a photoreactive group, but preferably component (b2) does not have a photoreactive group.

≪Viscosity≫
The viscosity of component (b2) is preferably in the range of 0.01 to 10 Pa·s, and preferably in the range of 0.05 to 5 Pa·s, from the viewpoint of its processing effect, storage stability, and fluidity. More preferably, it is particularly preferably in the range of 0.1 to 1 Pa·s.

Therefore, it is particularly preferable that component (b2) is a linear polyorganosiloxane represented by the following formula (2).

〔式中、
Ｌ３は、２３℃での粘度を０．０１～１０Ｐａ・ｓの範囲とする数であり、
Ｒ^４は、独立して、Ｃ１～Ｃ９アルキル基又はＣ６～Ｃ２０アリール基であり、
Ｒ^５は、独立して、Ｃ１～９アルコキシ基であり、
Ｒ^６は、独立して、Ｃ１～Ｃ９アルキル基であり、
ｔは、１、２又は３である〕

[During the ceremony,
L3 is a number that makes the viscosity at 23 ° C. range from 0.01 to 10 Pa s,
R ⁴ is independently a C1-C9 alkyl group or a C6-C20 aryl group,
R ⁵ is independently a C1-9 alkoxy group,
R ⁶ is independently a C1-C9 alkyl group;
t is 1, 2 or 3]

t is preferably 2 or 3, particularly preferably 3. Furthermore, when t is 2 or more, all R ⁵ are preferably methoxy groups or ethoxy groups, particularly preferably methoxy groups. Therefore, it is particularly preferable that component (b2) is a polydimethylsiloxane capped with trialkoxysilyl groups at both ends.

≪Surface treatment≫
The surface treatment can be performed by known methods for surface treatment of silica. In such a method, (b1) unsurface-treated silica is treated dry (e.g., in the absence of component (A)) or wet (e.g., in the presence of component (A)) with component (b2). ) surface treatment method. Specifically, component (b1) and component (b2) are placed in a sealed container and subjected to a chemical reaction or physical adsorption at a temperature of room temperature (for example, 23°C) to 400°C, and then the decomposition products, etc. are removed. One example is a method of volatilization. Alternatively, component (A), component (b1), and component (b2) are mixed and kneaded using a kneader, a Banbury mixer, a two-roll mixer, a gate mixer, a planetary mixer, etc., and then, if necessary, under normal pressure or reduced pressure. An example of this is a method in which heat treatment is carried out at 50° C. to 200° C. for about 1 hour to 20 hours using the above-mentioned kneader, dryer, etc. During the surface treatment process, as the degree of treatment progresses, fluidity and transparency tend to improve, and replasticization decreases. Note that the amount of silanol groups treated on the silica surface is not particularly limited as long as it is an amount that can be achieved by a normal surface treatment process.

≪Preferred embodiment≫
Component (B) is preferably silica surface-treated with a linear polyorganosiloxane represented by the above formula (2), and is an unsurface-treated atomized silica having a BET surface area of 50 to 500 m ² /g. It is particularly preferable that the silica be surface-treated with polydimethylsiloxane whose both ends are capped with trialkoxysilyl groups.
Component (B) may be one type or a combination of two or more types.

<(C) Photoreaction initiator>
Component (C) is a photoreaction initiator. The photoreaction initiator is excited by receiving light, gives excitation energy to the siloxane having a photoreactive group, and starts a curing reaction by irradiation with ultraviolet rays.

As a photoreaction initiator, aromatic hydrocarbons, acetophenone and its derivatives, benzophenone and its derivatives, o-benzoylbenzoic acid ester, benzoin and benzoin ether and its derivatives, xanthone and its derivatives, disulfide compounds, quinone compounds, halogenated Examples include hydrocarbons, amines, and organic peroxides.

From the viewpoint of compatibility with silicone and stability, compounds or organic peroxides containing substituted or unsubstituted benzoyl groups are more preferred. The photoreaction initiators may be used alone or in combination of two or more.

Examples of the photoreaction initiator include acetophenone, propiophenone, 2-hydroxy-2-methylpropiophenone, and 2,2-dimethoxy-1,2-diphenylethan-1-one (IRGACURE 651: manufactured by BASF). , 2-hydroxy-2-methyl-1-phenyl-propan-1-one (DAROCUR 1173: manufactured by BASF), 1-hydroxy-cyclohexyl-phenyl-ketone (IRGACURE 184: manufactured by BASF), 1-[4- (2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one (IRGACURE 2959: manufactured by BASF), 2-hydroxy-1-{4-[4-(2-hydroxy) -2-Methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one (IRGACURE 127: manufactured by BASF), 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropane- 1-one (IRGACURE 907: manufactured by BASF), 2-benzyl-2-dimethylamino-(4-morpholinophenyl)-butanone-1 (IRGACURE 369: manufactured by BASF), 2-(dimethylamino)-2- [(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone (IRGACURE 379: manufactured by BASF); 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (LUCIRIN) TPO: manufactured by BASF), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (IRGACURE 819: manufactured by BASF); 1,2-octanedione, 1-[4-(phenylthio)-,2- (O-benzoyloxime)] (IRGACURE OXE 01: manufactured by BASF), ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O- Acetyloxime) (IRGACURE OXE 02: manufactured by BASF); A mixture of oxyphenylacetic acid, 2-[2-oxo-2-phenylacetoxyethoxy]ethyl ester and oxyphenylacetic acid, 2-(2-hydroxyethoxy)ethyl ester ( IRGACURE 754: manufactured by BASF), phenylglyoxylic acid methyl ester (DAROCUR MBF: manufactured by BASF), ethyl-4-dimethylaminobenzoate (DAROCUR EDB: manufactured by BASF), 2-ethylhexyl-4-dimethylaminobenzoate ( DAROCUR EHA: manufactured by BASF), bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide (CGI 403: manufactured by BASF), benzoyl peroxide, cumene peroxide, and the like.

In terms of compatibility and photoreactivity, acetophenone, propiophenone, 2-hydroxy-2-methylpropiophenone, 2,2-dimethoxy-1,2-diphenylethan-1-one (IRGACURE 651: manufactured by BASF) ), 2-hydroxy-2-methyl-1-phenyl-propan-1-one (DAROCUR 1173: manufactured by BASF), 1-hydroxy-cyclohexyl-phenyl-ketone (IRGACURE 184: manufactured by BASF), 2-methyl- 1-(4-methylthiophenyl)-2-morpholinopropan-1-one (IRGACURE 907: manufactured by BASF), 2-benzyl-2-dimethylamino-(4-morpholinophenyl)-butanone-1 (IRGACURE 369) : manufactured by BASF), 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (LUCIRIN TPO: manufactured by BASF), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (IRGACURE 819: manufactured by BASF) ) is preferred.
Component (C) may be one type or a combination of two or more types.

<Other ingredients>
The ultraviolet curable silicone composition may contain additional components as long as the effects of the present invention are not impaired. Such components include (D) curing catalyst, (E) crosslinking agent, (F) reaction diluent, silicone that does not have a photoreactive group but has a moisture-reactive group, polymerization inhibitor, antioxidant, and light resistance. Examples include ultraviolet absorbers, light stabilizers, etc., which are sex stabilizers. None of the further components corresponds to component (A), component (B) or component (C).

Each of the additional components may be one type or a combination of two or more types. for example,
Further components may be a combination of one or more (D) curing catalysts, one or more (E) crosslinkers, and one or more (F) reactive diluents.

((D) Curing catalyst)
Component (D) is a curing catalyst. Component (D) is a component that acts as a condensation catalyst for advancing the curing reaction due to moisture, and is preferably a component that serves as a curing catalyst for the condensation reaction of moisture-reactive groups. Further, in the ultraviolet curable silicone composition, it is preferable that component (A) has a moisture-reactive group, and the ultraviolet curable silicone composition further contains component (D). Component (D) includes Lewis acids, amine catalysts, and organometallic compounds (for example, organometallic compounds containing tin, zirconium, titanium, zinc, and calcium).

Examples of organometallic compounds include dibutyltin dilaurate (DBTDL), dimethyltin dioleate, dimethyltin dilaurate, dibutyltin dioleate, diphenyltin diacetate, dibutyltin oxide, dibutyltin dimethoxide, dibutylbis(triethoxysiloxy)tin, dioctyltin dilaurate, Organic tin compounds such as dibutyltin diacetylacetonate; organic zirconium compounds such as tributoxyzirconium acetylacetonate; organic titanium compounds such as diisopropoxytitanium bis(acetylacetonate), tetrapropoxytitanium, tetrabutoxytitanium, tetraoctyl titanate, etc. can be mentioned. Examples of commercially available curing catalysts include Fomrezr® UL-28, Neostann® U-220H, and the like.

Component (D) is preferably an organometallic compound, and preferably one or more selected from the group consisting of organotin compounds, organozirconium compounds, and organotitanium compounds. Moreover, from the viewpoint of excellent surface curability, component (D) is particularly preferably an organic tin compound.
Component (D) may be one type or a combination of two or more types.

((E) Crosslinking agent)
The crosslinking agent is a silane compound having two or more reactive functional groups. Component (E) is a component that functions as an adhesion promoter. When the composition contains component (E), the adhesiveness with the base material is further improved. However, component (E) is not component (A).

As used herein, the term "reactive functional group" refers to a group of functional groups including a photoreactive functional group and a moisture-reactive functional group. Examples of the reactive functional groups contained in component (E) include C2 to C6 alkenyl groups, epoxy groups, C1 to C9 alkoxy groups, (meth)acryloyl groups, (meth)acryloyloxy groups, amino groups, mercapto groups, etc. . The reactive functional groups contained in component (E) may be the same or different.

Such component (E) is preferably one or more selected from the group consisting of components (E1) to (E4) below.

(E1) (R ⁸ ) _4-v An alkoxysilane compound represented by Si(OR ⁸ ) _v , and/or its partially hydrolyzed condensate (E2) Si(OR ⁷ ) _u group, an epoxy group-containing group, and a fat a silane compound having at least one group of group unsaturated hydrocarbon groups, and/or a partially hydrolyzed condensate thereof;
(E3) An isocyanurate compound having a Si(OR ⁷ ) _u group and/or a partially hydrolyzed condensate thereof, and (E4) a silane compound other than components (E1) to (E3) and/or a partial hydration thereof decomposition condensate,
(In each of the above formulas, R ⁷ represents a C1-C9 alkyl group or a C1-C9 alkyl group substituted with a C1-C9 alkoxy group (for example, a 2-methoxyethyl group); R ⁸ represents a C1-C9 represents an alkyl group; u is an integer of 1 to 3; v is an integer of 1 to 4, preferably an integer of 2 to 4)

(E1) includes di-, tri-, and tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, and dimethyldiethoxysilane. , and/or a partially hydrolyzed condensate thereof.

(E2) includes a silane compound having a Si(OR ⁷ ) _u group and an epoxy group-containing group, a silane compound having a Si(OR ⁷ ) _u group and an aliphatic unsaturated hydrocarbon group, and a Si(OR ⁷ ) u group and an aliphatic unsaturated hydrocarbon group. Examples include silane compounds having a _u group, an epoxy group-containing group, and an aliphatic unsaturated hydrocarbon group.

Examples of the silane compound having a Si(OR ⁷ ) _u group and an epoxy group-containing group include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and 3-glycidoxypropyl(methyl)dimethoxy. Silane, 3-glycidoxypropyl group-containing alkoxysilanes such as 3-glycidoxypropyl(methyl)diethoxysilane; 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; - 2-(3,4-epoxycyclohexyl)ethyl group-containing alkoxysilanes such as epoxycyclohexyl)ethyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl(methyl)dimethoxysilane, and/or their Examples include partially hydrolyzed condensates.

Examples of the silane compound having a Si(OR ⁷ ) _u group and an aliphatic unsaturated hydrocarbon group include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, methylvinyldimethoxysilane, and allyltrimethoxysilane. Alkenylalkoxysilanes such as silane, allyltriethoxysilane, methylallyldimethoxysilane; 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-acryloxypropyl(methyl)dimethoxysilane, 3- (meth)acryloxypropylalkoxysilanes such as methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropyl(methyl)dimethoxysilane; 1,1,3,5,7-penta Examples include organosilicon compounds such as reaction products of methylcyclotetrasiloxane and 3-methacryloxypropyltrimethoxysilane, and/or partially hydrolyzed condensates thereof.
Note that component (E2) is preferably not (E3). That is, component (E2) is preferably not an isocyanurate compound.

(E3) includes tris(trialkoxylylalkyl)isocyanurates such as tris(trimethoxysilylpropyl)isocyanurate and tris(triethoxysilylpropyl)isocyanurate; alkenyls such as triethoxysilylpropyl diallyl isocyanurate; and alkoxysilyl groups, and/or partially hydrolyzed condensates thereof.

Examples of (E4) include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyltrimethoxysilane. In addition, components known as silane coupling agents can be used as component (E).

Component (E) may be used alone or in combination of two or more.

((F) Reaction diluent)
Component (F) is a reaction diluent. When the ultraviolet curable silicone composition contains component (F), the viscosity of the composition can be adjusted, and the ultraviolet curability of the surface is further improved. Examples of component (F) include (meth)acrylate compounds having one or more (meth)acryloyl groups in the molecule, polyorganosiloxanes having one photoreactive group in the molecule, and the like. Here, the polyorganosiloxane having one photoreactive group in the molecule is as described above for component (A) except that it has one photoreactive group in the molecule. Note that the (meth)acrylate compound preferably does not contain a silicon atom in its molecule.

Examples of the (meth)acrylate compound include aliphatic (meth)acrylate compounds, alicyclic (meth)acrylate compounds, aromatic (meth)acrylate compounds, and (meth)acrylate resins.

Examples of aliphatic (meth)acrylate compounds include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 1,6-hexanediol diacrylate, tripropylene glycol diacrylate, dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate, and pentaerythritol pentaacrylate. Examples include erythritol tetraacrylate and dipentaerythritol tetraacrylate.
Examples of the alicyclic (meth)acrylate compound include isobornyl (meth)acrylate, tetrahydrofurfuryl acrylate, and the like.
Examples of the (meth)acrylate resin include urethane (meth)acrylate resin. Commercially available (meth)acrylate resins include Shiko UV-1700B, Shiko UV-6300B, Shiko UV-7640B (manufactured by JSR Corporation), Ebecryl 1290 (manufactured by Daicel Cytec), and UA-306H (manufactured by Kyoeisha Chemical Co., Ltd.). ) etc.

Component (F) is preferably a mono(meth)acrylate compound having one (meth)acryloyl group in the molecule, particularly preferably an alicyclic mono(meth)acrylate compound.
Component (F) may be used alone or in combination of two or more.

(Other further ingredients)
When component (A) does not have a moisture-reactive group, the ultraviolet curable silicone composition preferably contains a silicone that does not have a photoreactive group but has a moisture-reactive group. When the UV-curable silicone composition contains a silicone that does not have a photoreactive group but has a moisture-reactive group, the UV-curable silicone can be made into a light- and moisture-curable composition. The silicone which does not have a photoreactive group but has a moisture-reactive group is the same as described above for component (A), except that it does not have a photoreactive group.

Examples of the polymerization inhibitor include hydroquinone, p-methoxyphenol, t-butylcatechol, and phenothiazine.

The antioxidant can be used to prevent oxidation of the cured product of the composition and improve weather resistance, and examples thereof include hindered amine-based and hindered phenol-based antioxidants. Examples of hindered amine antioxidants include N,N',N'',N'''-tetrakis-(4,6-bis(butyl-(N-methyl-2,2,6,6-tetramethylpiperidine- 4-yl)amino)-triazin-2-yl)-4,7-diazadecane-1,10-diamine, dibutylamine/1,3,5-triazine/N,N'-bis-(2,2,6 ,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine/N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine polycondensate, poly[{6-(1, 1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2 , 2,6,6-tetramethyl-4-piperidyl)imino}], a polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol, [decanedioic acid bis (2,2,6,6-tetramethyl-1(octyloxy)-4-piperidyl) ester, reaction product of 1,1-dimethylethyl hydroperoxide and octane (70%)]-polypropylene (30%), Bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butyl malonate, methyl 1,2, 2,6,6-pentamethyl-4-piperidyl sebacate, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) ) sebacate, 1-[2-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]ethyl]-4-[3-(3,5-di-tert-butyl-4 -hydroxyphenyl)propionyloxy]-2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 8-acetyl-3-dodecyl-7,7,9 , 9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione, etc., but are not limited to these. Examples of hindered phenolic antioxidants include: For example, pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], thiodiethylene-bis[3-(3,5-di-tert-butyl-4-hydroxy) phenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), N,N'-hexane-1,6-diylbis[3-(3,5-di- tert-butyl-4-hydroxyphenylpropioamide), benzenepropanoic acid 3,5-bis(1,1-dimethylethyl)-4-hydroxyC7-C9 side chain alkyl ester, 2,4-dimethyl-6-(1 -methylpentadecyl)phenol, diethyl [[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonate, 3,3',3",5,5',5"-hexane -tert-butyl-4-a,a',a''-(mesitylene-2,4,6-tolyl)tri-p-cresol, calcium diethylbis[[[3,5-bis-(1,1-dimethyl ethyl)-4-hydroxyphenyl]methyl]phosphonate], 4,6-bis(octylthiomethyl)-o-cresol, ethylenebis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m -tolyl)propionate], hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,3,5-tris(3,5-di-tert-butyl-4 -hydroxybenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, reaction product of N-phenylbenzenamine and 2,4,4-trimethylpentene, 2 , 6-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazin-2-ylamino)phenol and the like, but are not limited thereto. The above antioxidants may be used alone or in combination of two or more.

The light stabilizer can be used to prevent photooxidative deterioration of the cured product, and examples thereof include benzotriazole-based, hindered amine-based, and benzoate-based compounds. Ultraviolet absorbers, which are light resistance stabilizers, can be used to prevent photodeterioration and improve weather resistance. For example, ultraviolet absorbers such as benzotriazole-based, triazine-based, benzophenone-based, benzoate-based, etc. etc. Examples of the ultraviolet absorber include 2,4-di-tert-butyl-6-(5-chlorobenzotriazol-2-yl)phenol, 2-(2H-benzotriazol-2-yl)-4,6- Di-tert-pentylphenol, 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, methyl 3-(3-(2H-benzotriazol-2-yl) -yl)-5-tert-butyl-4-hydroxyphenyl)propionate/polyethylene glycol 300 reaction product, 2-(2H-benzotriazol-2-yl)-6-(linear and side-chain dodecyl)-4 - Benzotriazole UV absorbers such as methylphenol, triazine UV absorbers such as 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]-phenol benzophenone UV absorbers such as octabenzone, benzoate UV absorbers such as 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate, etc. It is not limited to. The above ultraviolet absorbers may be used alone or in combination of two or more. As the light stabilizer, hindered amine type is preferable. Among these, it is preferable to use a hindered amine light stabilizer containing a tertiary amine in order to improve the storage stability of the composition. Examples of tertiary amine-containing hindered amine light stabilizers include Tinuvin 622LD, Tinuvin 144, CHIMASSORB119FL (all manufactured by BASF); MARK LA-57, LA-62, LA-67, LA-63 (all manufactured by Asahi Examples include light stabilizers such as Sanol LS-765, LS-292, LS-2626, LS-1114, and LS-744 (all manufactured by Sankyo Co., Ltd.);

(Content of ingredients)
The content of component (A) is preferably 30 to 98 parts by mass, particularly 40 to 80 parts by mass, when the total of components (A) to (C) is 100 parts by mass. preferable.
The content of component (B) should be 1 to 30 parts by mass when the total of components (A) to (C) is 100 parts by mass, since it has better mechanical properties such as tensile strength. The amount is preferably 3 to 20 parts by weight, more preferably 3 to 15 parts by weight.
The amounts of component (b1) and component (b2) can be appropriately set depending on the desired degree of surface treatment, but are preferably 100 to 500 parts by mass relative to 100 parts by mass of component (b1). Particularly preferably from 200 to 400 parts by mass.
The content of component (C) is 0.01 to 5 parts by mass when the total of components (A) to (C) is 100 parts by mass, from the viewpoint of coloring the cured product by the photoinitiator. The amount is preferably 0.02 to 2 parts by mass, particularly preferably 0.02 to 2 parts by mass.
The content of component (D) is preferably 0.01 to 2 parts by mass, and preferably 0.03 to 1 part by mass, when the total of components (A) to (C) is 100 parts by mass. It is particularly preferable.
The content of component (E) is preferably 0.01 to 10 parts by mass, and preferably 0.05 to 5 parts by mass, when the total of components (A) to (C) is 100 parts by mass. It is particularly preferable. When the content of component (E) is 0.01 part by weight or more when the total of components (A) to (C) is 100 parts by mass, the storage stability of the composition is improved. The storage stability is further improved, and when it exceeds 10 parts by weight, a part of it does not separate from the system during storage, does not cause significant shrinkage during curing, and reduces the physical properties of the obtained rubber-like elastic body. It can be suppressed. Furthermore, when component (E) has a reactive group with higher crosslinking properties such as an alkoxy group, the amount of component (E) to be blended can be reduced.
The content of component (F) is preferably 0 to 30 parts by mass, particularly preferably 0 to 20 parts by mass, when the total of components (A) to (C) is 100 parts by mass. . When the content of component (F) is within the above range, curing shrinkage of the composition does not become too large, and heat resistance improves.
The total content of components other than components (D) to (F) is preferably 20% by mass or less of the composition, particularly preferably 0.01 to 10% by mass.
Further, the content of component (A) in the ultraviolet curable silicone composition is preferably 50% by mass or more, particularly preferably 60% by mass to 98% by mass.

(Characteristic)
From the viewpoint of workability during coating, the ultraviolet curable silicone composition preferably has a viscosity at 23°C of 0.01 to 1,000 Pa·s, and preferably 0.05 to 700 Pa·s. More preferably, it is 0.10 to 500 Pa·s.

[Production method of ultraviolet curable silicone composition]
The ultraviolet curable silicone composition can be obtained by blending component (A), component (B), component (C), and additives as necessary. Specifically, for example, components (A), (B), and (C) are mixed into a 5L universal mixer and stirrer equipped with a vacuum degassing device in a room where foreign substances in the air are controlled, such as a clean room. and mix uniformly at room temperature for 30 minutes. Then, add additives such as polymerization inhibitors as necessary in a room where ultraviolet rays are removed, such as a yellow room, and cool with ice water (below 10℃). ), the mixture can be prepared by uniformly mixing the mixture under reduced pressure while cooling for 30 minutes, defoaming the mixture, and then filtering the mixture using a wire mesh filter having a fineness of 200 mesh or the like. Here, the room temperature is preferably 10 to 30°C, particularly preferably 23°C.

[Curing method of ultraviolet curable silicone composition]
The ultraviolet curable silicone composition is a photo (ultraviolet) curable composition because it contains the component (A) having a photoreactive group. The ultraviolet curable silicone composition can be cured by irradiating it with ultraviolet light. Examples of lamps in the wavelength range in which the component (A) having a photoreactive group can react include high-pressure mercury lamps (UV-7000) and metal halide lamps (MHL-250 and MHL-450 manufactured by Ushio Inc.). , MHL-150, MHL-70), South Korea: Metal halide lamp manufactured by JM tech (JM-MTL 2KW), ultraviolet irradiation lamp manufactured by Mitsubishi Electric Corporation (OSBL360), ultraviolet irradiation machine manufactured by Nippon Battery Co., Ltd. (UD -20-2), Toshiba Corporation's fluorescent lamp (FL-20BLB)), Fusion's H bulb, H plus bulb, D bulb, Q bulb, M bulb, etc. The amount of ultraviolet ray irradiation is preferably 100 to 12,000 mJ/cm ² , more preferably 300 to 8,000 mJ/cm ² , and particularly preferably 500 to 6,000 mJ/cm ² .

When component (A) has a moisture-reactive group, the ultraviolet curable silicone composition can be a light- and moisture-curable composition. Further, it is preferable that component (A) has a moisture-reactive group, and the ultraviolet curable silicone composition further contains component (D). When the ultraviolet curable silicone composition is a light and moisture curable composition, it can be cured by bringing the composition into contact with surrounding humid air. Due to the curing reaction caused by moisture, even shadowed areas that cannot be irradiated with light can be cured, and sufficient adhesive strength can be ensured. The temperature for curing with moisture is not particularly limited, but it is preferably carried out at room temperature (23° C.). Further, the reaction time can be appropriately set depending on the temperature. Due to the moisture-reactive group, the curing reaction can proceed without applying more heat than necessary, and deformation of the base material can be prevented. More preferably, the ultraviolet curable silicone composition is stored in a moisture-proof container.

In addition to the above-mentioned curing step, the ultraviolet curable silicone composition can also be heated at a temperature of 50 to 80° C., if necessary, to further accelerate curing and increase adhesive strength. The heating time can be set as appropriate, but is preferably 0.1 to 3 hours.

The coating thickness of the ultraviolet curable silicone composition is not particularly limited, but is preferably 10 to 10,000 μm, and more preferably 10 to 5,000 μm from the viewpoint of quick temporary fixing time.

[Application]
The ultraviolet curable silicone composition can be used as an adhesive for image display devices. The ultraviolet curable silicone composition can be suitably used in an image display device, and is particularly preferred as a resin interposed between a protection portion and an image display portion of a flat panel type image display device. Specifically, after applying an ultraviolet curable silicone composition on a protective panel constituting a transparent protective section made of optical plastic or the like, an image display panel constituting an image display section is bonded together, and ultraviolet rays are applied. It can be irradiated. The protective panel may be provided with a step on the outer periphery to prevent the composition of the present invention from flowing out. Thereby, an image display device is obtained in which the image display section and the protection section are sealed using the adhesive for image display devices.

UV-curable silicone compositions are liquid and have excellent coating properties, do not reduce visibility, enable high-brightness and high-contrast display, and can provide curable resins with high durability. . The ultraviolet curable silicone composition is suitable for manufacturing large-screen image display devices or for manufacturing ultra-thin image display devices. Here, the image display panel in the large-sized image display device is preferably 5 to 100 inches, more preferably 7 to 80 inches, and particularly preferably 10 to 60 inches. Further, the thickness of the ultra-thin image display device is preferably 10 to 500 μm, more preferably 20 to 450 μm, and particularly preferably 50 to 400 μm.

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples. Parts and % represent parts by mass and % by mass unless otherwise specified. The present invention is not limited to these examples. Each composition was irradiated with light using UVL-4001M manufactured by Ushio Inc., with an ultraviolet energy irradiation amount of 120 W/cm ² under the following light irradiation conditions (integrated light amount).

[Evaluation conditions for physical properties]
(1) Viscosity Using a rotational viscometer (Vismetron VDA-L) (manufactured by Shibaura System Co., Ltd.), No. Measurements were made at 23° C. and 60 rpm using 2-4 rotors.
(2) Deep curability The composition was filled into a polystyrene cup whose sides and bottom were shielded from light, and the cured thickness after light irradiation was measured under light irradiation conditions: 3,000 mJ/cm ² .
(3) Tensile strength The composition was extruded into a sheet with a thickness of 2 mm, and after irradiation under irradiation conditions of 3,000 mJ/ ^cm2 , it was left at 23°C, 50% RH for 7 days with the light blocked, and then exposed to air. It was made to harden by the humidity of , and was measured based on JIS K 6301.

(4) Elongation The composition was extruded into a sheet with a thickness of 2 mm, and after irradiation with irradiation conditions of 3,000 mJ/ ^cm2 , it was left at 23°C, 50% RH for 7 days with the light blocked, and the moisture in the air was removed. was cured and measured in accordance with JIS K 6301.
(5) Hardness The composition was extruded into a sheet with a thickness of 2 mm, and after irradiation under irradiation conditions of 3,000 mJ/ ^cm2 , it was left for 7 days at 23°C and 50% RH with the light blocked, and then It was cured by moisture and measured in accordance with JIS K 6301.

(6) Surface condition The surface of the composition after irradiation with ultraviolet rays was observed, and the surface condition was evaluated based on the following criteria. In addition, ◎～〇 is between ◎ and 〇.
◎: Good (no tackiness, good hardening condition)
○: Slightly tacky (slightly tacky)
△: Has tackiness (has tackiness and cannot maintain surface condition after touching with fingers)
×: There is a liquid substance and uncured state is confirmed.
(7) Adhesive strength Adhesive conditions FR4: Epoxy glass test piece (2 x 25 x 80 mm), slide glass test piece (1 x 26 x 76 mm), adhesive surface (10 x 20 mm), film thickness 1 mm. It was coated, irradiated with light from the slide glass side, irradiated with light irradiation conditions of 3,000 mJ/cm ² , and then left for 7 days at 23° C. and 50% RH, and then measured.

(8) Cohesive failure The fracture state of the material during the above adhesive strength measurement was visually observed, and the area ratio of cohesive failure (material fracture) was expressed.
(9) Tack-free time after UV curing After irradiating the composition with light at 3,000 mJ/ ^cm2 , leave it in an atmosphere of 23°C and 50% RH, and touch the surface with your finger to dry it. We measured the time it took to confirm that this was the case.
(10) Tack-free time for moisture curing only The composition was extruded into an atmosphere of 23°C and 50% RH under UV protection, and the time required to confirm that it was dry by touching the surface with a finger was measured. did.

[Ingredients used]
The components used in the examples and comparative examples are as follows.
(1) Component (A): Polyorganosiloxane having two or more photoreactive groups in the molecule (A1) α,ω-(3-acryloxypropyl)dimethoxysilylpolydimethylsiloxane (1) Viscosity 0.980 Pa・s
(A2) α,ω-(3-acryloxypropyl)dimethoxysilylpolydimethylsiloxane (2) Viscosity 6.800 Pa・s
(2) Component (B): Silica surface-treated with polyorganosiloxane having two or more alkoxysilyl groups in the molecule (b1) Unsurface-treated silica b1-1: Atomized silica with a specific surface area of 300 m ² /g ( Aerosil 300, manufactured by Nippon Aerosil Co., Ltd.)
b1-2: Fumed silica with a specific surface area of 200 m ² /g (Aerosil 200, manufactured by Nippon Aerosil Co., Ltd.)
b1-2: Atomized silica with a specific surface area of 140 m ² /g (Rheolo Seal QS-10, manufactured by Tokuyama Co., Ltd.)
(b2) Polyorganosiloxane having two or more alkoxysilyl groups in the molecule b2-1: α,ω-trimethoxysilyl polydimethylsiloxane Viscosity 0.660 Pa・s
(3) Component (C): Photoinitiator C-1: 2,2-dimethoxy-1,2-diphenylethan-1-one (IRGACURE 651: manufactured by BASF)
C-2: 1-hydroxycyclohexyl-phenyl ketone (IRGACURE 184: manufactured by BASF),
C-3: Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (IRGACURE 819: manufactured by BASF)
(4) Other components (4-1) Component (B'): Silica surface-treated with hexamethyldisilazane B'-1: Atomized silica (unsurface treated) with a specific surface area of 300 m ² /g was mixed with hexamethyldisilazane. Silica surface-treated with methyldisilazane (Rheolo Seal HM-30S, specific surface area 200 m ² /g, carbon content 3.5% by weight, manufactured by Tokuyama Co., Ltd.)
B'-2: Silica obtained by surface-treating fumed silica (unsurface treated) with a BET specific surface area of 200 m ² /g with hexamethyldisilazane (silica 1, carbon content 3.8% by weight)
B'-3: Silica (silica 2, carbon content 2.0% by weight) obtained by surface-treating fumed silica (unsurface treated) with a BET specific surface area of 130 m ² /g with hexamethyldisilazane.
(4-2) Component (D): Curing catalyst d-1: Dibutyltin bis(acetylacetate)
d-2: dibutyltin bis(triethoxysiloxy)
d-3: Dibutyltin dilaurate d-4: Zirconium compound: (n-C ₄ H ₉ O) ₃ Zr (C ₅ H ₇ O ₂ ) tributoxyzirconium acetylacetonate (manufactured by Matsumoto Fine Chemical Co., Ltd., ZC-540) , active ingredient 45% by weight, metal content 10.2% by weight
(4-3) Component (E): Crosslinking agent e-1: Methyltrimethoxysilane e-2: 1,3,5-tris(trimethoxysilylpropyl)isocyanurate e-3: 3-glycidoxypropyltrimethoxy Silane (4-4): Component (F): Reaction diluent f-1: Isobornyl acrylate

[Conditions for manufacturing the composition]
(Example 1)
(1) Surface treatment of silica Put (b1) unsurface-treated silica and (b2) polyorganosiloxane having two or more alkoxysilyl groups in the molecule into a 5L universal mixer (manufactured by Dalton), and place at room temperature (20 The mixture containing component (B) (i.e., the alkoxysilyl group is added to the A mixture component containing silica surface-treated with a polyorganosiloxane having two or more polyorganosiloxanes was obtained.
(2) Preparation of composition Component (B) obtained in (1) above and components other than component (B) were put into a 5L universal mixer (manufactured by Dalton), and the mixture was heated to room temperature (23°C). ) for 30 minutes. The resulting mixture was filtered through a 200-mesh wire mesh filter to remove foreign matter and the like to obtain an ultraviolet curable silicone composition.

(Examples 2 to 9)
The compositions of Examples 2 to 9 were produced in the same manner as Example 1.

(Comparative example 1)
Component (A) and component (B) were mixed uniformly at room temperature (20 to 30°C) for 30 minutes in a 5L universal mixer (manufactured by Dalton), and then at 100°C for 2 hours under reduced pressure. After heating and mixing, the remaining components shown in the table were added, and the resulting mixture was filtered through a 200-mesh wire mesh filter to remove foreign matter and the like to obtain an ultraviolet curable silicone composition.

(Comparative Examples 2 to 10)
Compositions of Comparative Examples 2 to 10 were produced in the same manner as Comparative Example 1.

The properties described above were measured for the resulting composition. The formulations of each Example and Comparative Example and the measurement results of each characteristic are shown in Tables 1 to 3.

Table 1 shows that the composition of Example 1 had a smaller viscosity change rate than the corresponding composition of Comparative Example 1.
A comparison between Example 1 and Examples 2 to 9 revealed that when the composition further contained (D) a curing catalyst, the tack-free time after room temperature curing became shorter and the surface condition improved.
A comparison between Examples 2 to 4 and Example 5 revealed that (D) when the curing catalyst was a tin-based catalyst, the surface curing properties were better and the tack-free time was shorter.
A comparison of Examples 2, 6, and 7 revealed that when the amount of (B) surface-treated silica was increased, tensile strength, hardness, adhesive strength, etc. were better.
A comparison of Examples 2, 8, and 9 revealed that when the surface area of (b1) unsurface-treated silica, which is the raw material for (B) surface-treated silica, increased, the deep hardenability was better.
Comparative Examples 1 to 7 did not contain silica surface-treated with component (b2), so the initial (immediately) viscosity was high, the viscosity increased significantly, and the long-term storage stability was poor.
Comparative Examples 8 to 10 had a lower viscosity than the composition containing (B'), but because they contained (b1) unsurface-treated silica, the viscosity increased significantly and the long-term storage stability was poor.

Claims (7)

(A) polyorganosiloxane having two or more photoreactive groups in the molecule,
(B) silica surface-treated with polyorganosiloxane having two or more alkoxysilyl groups in the molecule, and (C) a photoreaction initiator,
An ultraviolet curable silicone composition comprising: (A) is the following formula (1):

[In formula (1),
R ¹ is independently a C1 to C9 alkyl group, a C6 to C12 aryl group, a C1 to C9 alkyl group substituted with 1 to 3 (meth)acryloyl groups and/or (meth)acryloyloxy groups, (meth)acryloyl group, (meth)acryloyloxy group, C1-C9 alkyl group substituted with 1-3 C1-C9 alkoxy groups, or C1-9 alkoxy group,
At least one R is a C1 to C9 alkyl group, (meth)acryloyl group, or (meth)acryloyloxy group substituted with 1 to 3 (meth)acryloyl groups and/or (meth)acryloyloxy groups. and
L1 is a value that makes the viscosity at 23°C 0.01 to 100 Pa·s]
The ultraviolet curable silicone resin composition according to claim 1, which is an organopolysiloxane represented by: (B) is the following formula (2):

[During the ceremony,
L3 is a number that makes the viscosity at 23 ° C. range from 0.01 to 100 Pa s,
R ⁴ is independently a C1-C6 alkyl group or a C6-C12 aryl group,
R ⁵ is independently a C1-C9 alkyl group substituted with 1 to 3 C1-C9 alkoxy groups, or a C1-9 alkoxy group;
R ⁶ is independently a C1-C6 alkyl group or a C6-C12 aryl group,
t is 1, 2 or 3]
The ultraviolet curable silicone resin composition according to claim 1 or 2, which is silica surface-treated with a polyorganosiloxane represented by: The ultraviolet curable silicone composition according to any one of claims 1 to 3, wherein component (A) has a moisture-reactive group and the composition further comprises (D) a curing catalyst. The ultraviolet curable silicone composition according to any one of claims 1 to 4, further comprising (E) a crosslinking agent. An adhesive for image display devices, comprising the ultraviolet curable silicone composition according to any one of claims 1 to 5. An image display device, wherein an image display section and a protection section are sealed using the adhesive for an image display device according to claim 6.