JP2019167544A - Ultraviolet curable silicone resin composition, and image display device using the same - Google Patents

Abstract

An ultraviolet-curable silicone resin composition that provides a cured product having excellent UVA resistance. (A) A specific linear polyorganosiloxane containing an aliphatic unsaturated group; (B) a mercaptoalkyl group bonded to a silicon atom and having a viscosity of 10 to 10,000 cP at 23 ° C. (C) an acylphosphine oxide compound selected from a group of compounds having a specific structural unit; (D) a benzotriazole compound selected from a group of compounds having a specific structural unit; and (E) a specific structural unit. A hindered amine compound selected from the group of compounds, wherein the ratio of the number of mercaptoalkyl groups in (B) to the number of aliphatic unsaturated groups in (A) is 0.1 to 10, and (A) to (E) An ultraviolet-curable silicone resin composition wherein (C), (D), and (E) satisfy a specific compounding ratio in a total of 100% by weight. [Selection diagram] None

Description

  The present invention relates to an ultraviolet curable silicone resin composition that can be suitably used for an image display device, and an image display device using the same.

  In recent years, attention has been focused on flat panel image display devices such as liquid crystal, plasma, and organic EL. A flat panel type image display device usually has a large number of pixels composed of a semiconductor layer, a phosphor layer, or a light emitting layer constituting an active element between a pair of light-transmitting substrates such as glass. It has a display area (image display portion) arranged in a matrix. Generally, the periphery of this display area (image display portion) and a protective portion formed of optical plastic such as glass or acrylic resin is sealed secretly with an adhesive.

  In such an image display device, an ultraviolet curable resin composition is interposed between the protective part and the image display part in order to prevent deterioration in visibility (visibility) due to reflection of outdoor light or indoor lighting. A thin image display device is manufactured, and an ultraviolet curable acrylic resin or an ultraviolet curable silicone resin composition is used as the ultraviolet curable resin composition used here (Patent Documents 1 and 2). On the other hand, an ultraviolet curable silicone resin composition composed of a polyorganosiloxane containing a mercaptoalkyl group and a polyorganosiloxane containing an aliphatic unsaturated group has been proposed (Patent Documents 3 and 4).

In addition, a linear polyorganosiloxane containing an aliphatic unsaturated group, a polyorganosiloxane containing a mercaptoalkyl group bonded to a silicon atom, an acylphosphine oxide photoinitiator, and acetophenone and / or propiophenone An ultraviolet curable silicone resin composition containing the same has been proposed (Patent Document 5). In the ultraviolet curable silicone resin composition described in Patent Document 5, acetophenone and propiophenone are used as compatibilizers for the photoinitiator.
In the ultraviolet curable resin composition described above, a high-pressure mercury lamp, an iron halide metal halide lamp or the like is usually used as a light source for generating ultraviolet rays, and exhibits excellent curability in these irradiations.

JP 2008-282000 A JP 7-134538 A JP-A-2-245060 Japanese Patent Laid-Open No. 3-064389 JP2013-253179A

  The ene-thiol type ultraviolet curable silicone resin as described in Patent Documents 3 to 5 including a polyorganosiloxane containing a mercaptoalkyl group and a polyorganosiloxane containing an aliphatic unsaturated group is a UVA for a long time. It has been found by the present inventors that when exposed to ultraviolet rays in the wavelength range, yellowing and clouding become prominent and bubbles are generated due to softening of the cured product.

  This invention makes it a subject to provide the ultraviolet curable silicone resin composition which provides the hardened | cured material which has the outstanding UVA resistance with respect to such a problem.

  The present inventors diligently studied to solve the above-described problems. As a result, in the ultraviolet curable silicone resin composition, a specific acylphosphine oxide compound, a specific benzotriazole compound, and a specific hindered amine compound are used in a specific amount. In this case, it was found that even when no further compatibilizing agent is present, they are compatible with each other and can be made compatible with the silicone resin component. Further, the present inventors have found that a cured product obtained by using an ultraviolet curable silicone resin composition in which the above components are mutually compatible has excellent UVA resistance, and has led to the present invention. The present invention includes the following aspects.

（式中、
各Ｒ^１は、独立して、脂肪族不飽和基であり、
各Ｒは、独立して、Ｃ１〜Ｃ６アルキル基又はＣ６〜Ｃ１２アリール基であって、Ｒのうち、１〜４０モル％はＣ６〜Ｃ１２アリール基であり、
ｎは、２３℃における粘度を１００〜１００，０００ｃＰとする数である）で示される、脂肪族不飽和基を含有する直鎖状ポリオルガノシロキサン；
（Ｂ）２３℃における粘度が１０〜１０，０００ｃＰである、ケイ素原子に結合するメルカプトアルキル基を含有するポリオルガノシロキサン；
（Ｃ）２，４，６−トリメチルベンゾイル−ジフェニルフォスフィンオキシド及びビス（２，４，６−トリメチルベンゾイル）−フェニルフォスフィンオキシドからなる群より選ばれるアシルフォスフィンオキシド化合物；
（Ｄ）３−（２Ｈ−ベンゾトリアゾール−２−イル）−４−ヒドロキシ−５−ｔｅｒｔ−ブチルベンゼンプロピオン酸のＣ_７〜Ｃ_９アルキルエステルからなる群より選ばれるベンゾトリアゾール化合物；並びに
（Ｅ）ビス（１−オクチルオキシ−２，２，６，６−テトラメチル−４−ピペリジル）セバケート、ビス（１，２，２，６，６−ペンタメチル−４−ピペリジル）セバケート及びメチル−１，２，２，６，６−ペンタメチル−４−ピペリジルセバケートからなる群より選ばれるヒンダードアミン化合物
を含み、ここで、
（Ａ）中の脂肪族不飽和基数に対する、（Ｂ）中のメルカプトアルキル基の個数の比が、０．１〜１０であり、
（Ａ）〜（Ｅ）の合計１００重量％中、（Ｃ）が０．０８〜０．２５重量％であり、（Ｄ）が０．５〜５．０重量％であり、（Ｅ）が０．１〜０．５重量％である、
紫外線硬化型シリコーン樹脂組成物に関する。
本発明の第２の態様は、（Ｅ）が、ビス（１−オクチルオキシ−２，２，６，６−テトラメチル−４−ピペリジル）セバケートである、本発明の第１の態様の組成物に関する。
本発明の第３の態様は、さらにシランカップリング剤を含む、本発明の第１又は第２の組成物に関する。
本発明の第４の態様は、本発明の第１〜第３の態様のいずれかの組成物からなる画像表示装置用シール剤に関する。
本発明の第５の態様は、本発明の第４の態様の画像表示装置用シール剤を用いて、画像表示部と保護部とが封止された画像表示装置に関する。 The first aspect of the present invention is:
(A) Formula (I):

(Where
Each R ¹ is independently an aliphatic unsaturated group;
Each R is independently a C1 to C6 alkyl group or a C6 to C12 aryl group, and 1 to 40 mol% of R is a C6 to C12 aryl group,
n is a number having a viscosity at 23 ° C. of 100 to 100,000 cP), and a linear polyorganosiloxane containing an aliphatic unsaturated group;
(B) a polyorganosiloxane containing a mercaptoalkyl group bonded to a silicon atom, having a viscosity at 23 ° C. of 10 to 10,000 cP;
(C) an acylphosphine oxide compound selected from the group consisting of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide;
(D) 3- (2H- benzotriazol-2-yl) -4- _C 7 ~C ₉ benzotriazole compounds chosen from the group consisting of alkyl esters of hydroxy -5-tert-butyl-benzenepropanoic acid; and (E) Bis (1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and methyl-1,2, A hindered amine compound selected from the group consisting of 2,6,6-pentamethyl-4-piperidyl sebacate, wherein
The ratio of the number of mercaptoalkyl groups in (B) to the number of aliphatic unsaturated groups in (A) is 0.1 to 10,
Of the total 100% by weight of (A) to (E), (C) is 0.08 to 0.25% by weight, (D) is 0.5 to 5.0% by weight, and (E) is 0.1 to 0.5% by weight,
The present invention relates to an ultraviolet curable silicone resin composition.
The second aspect of the present invention is the composition according to the first aspect of the present invention, wherein (E) is bis (1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate. About.
The third aspect of the present invention relates to the first or second composition of the present invention, further comprising a silane coupling agent.
A 4th aspect of this invention is related with the sealing compound for image display apparatuses which consists of a composition in any one of the 1st-3rd aspect of this invention.
A fifth aspect of the present invention relates to an image display device in which an image display unit and a protection unit are sealed using the sealant for an image display device of the fourth aspect of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the ultraviolet curable silicone resin composition which provides the hardened | cured material which has the outstanding UVA resistance is provided.

  The ultraviolet curable silicone resin composition (hereinafter also referred to as “composition”) is represented by (A) Formula (I):

(Where
Each R ¹ is independently an aliphatic unsaturated group;
Each R is independently a C1 to C6 alkyl group or a C6 to C12 aryl group, and 1 to 40 mol% of R is a C6 to C12 aryl group,
n represents a linear polyorganosiloxane containing an aliphatic unsaturated group represented by the following formula: n is a number with a viscosity at 23 ° C. of 100 to 100,000 cP.

In formula (I) for (A), R ¹ is an aliphatic unsaturated group. R ^{1 at} both ends may be the same or different, but is preferably the same.

  Aliphatic unsaturated groups include alkenyl groups such as C2-C6 alkenyl groups (eg, vinyl, propenyl, butenyl, hexenyl, etc.). An alkenyl group having an unsaturated terminal is more preferable, and a vinyl group is preferable from the viewpoint of ease of synthesis.

  In the formula (I), R is a C1-C6 alkyl group (for example, methyl, ethyl, propyl, etc.) or a C6-C12 aryl group (for example, phenyl, tolyl, xylyl, etc.). R may be the same or different.

  From the viewpoint of adjusting the refractive index, 1 to 40 mol% of R is a C6 to C12 aryl group, and from the viewpoint of viscosity and thixotropy, 1 to 20 mol% of R is a C6 to C12 aryl group. Preferably there is.

  From the viewpoint of ease of synthesis and the like, the C1-C6 alkyl group is preferably methyl, and the C6-C12 aryl group is preferably phenyl.

  As (A), in Formula (I), 1-40 mol% of R is a phenyl group, and the remainder is a methyl group, More preferably, 1-20 mol% of R is preferable. Is a phenyl group and the remainder is a methyl group.

  (A) has a viscosity at 23 ° C. of 100 to 100,000 cP, preferably 100 to 25,000 cP, more preferably 200 to 10,000 cP, more preferably 300 to 5, from the viewpoint of workability of the composition. 000 cP is particularly preferred. In the present specification, the viscosity is measured using a rotational viscometer (Bismetron VDA-L) (manufactured by Shibaura System Co., Ltd.). 2 to 4 are used, and the values are measured at 30 to 60 rpm and 23 ° C.

  The number of aliphatic unsaturated groups in (A) can be determined from the molecular weight obtained by calculating the average structural formula by NMR, calculating the molecular weight.

  The preparation method of (A) is not particularly limited, and for example, polycondensation and re-equilibration of chlorosilanes necessary for a desired structure such as dimethyldichlorosilane, diphenyldichlorosilane, methylphenyldichlorosilane, dimethylvinylchlorosilane and the like are performed. Or obtained by cohydrolyzing alkoxysilanes necessary for the desired structure such as dimethyldimethoxysilane, diphenyldimethoxysilane, methylphenyldimethoxysilane, dimethylvinylmethoxysilane, etc., and performing polycondensation and re-equilibration reactions Can do. Moreover, 1,1,3,3,5,5,7,7-octamethylcyclotetrasiloxane, 1,1,3,3,5,5,7,7-octaphenylcyclotetrasiloxane, 1,1, Siloxanes necessary for a desired structure such as 3,3-tetramethyl-1,3-divinyldisiloxane can be converted to an alkali catalyst (alkali metal hydroxide, alkali metal silanolate, ammonium hydroxide, etc.) or acid catalyst (sulfuric acid). , Silanolate sulfate, trifluoromethanesulfonic acid) in the presence of ring-opening polymerization and re-equilibration.

(A) may be used alone or in combination of two or more. In addition, when (A) is a mixture of two or more kinds, polyorganosiloxane having a high viscosity (for example, a viscosity at 23 ° C. of 10,000 to 25,000 cP) as (A) and a low viscosity (for example, The viscosity at 23 ° C. can be a mixture with 100 to 5,000 cP) polyorganosiloxane.
By setting it as such a mixture, there exists a tendency for the hardened | cured material which UVA resistance is more excellent to be obtained.

  The composition of the present invention contains (B) a polyorganosiloxane containing a mercaptoalkyl group bonded to a silicon atom and having a viscosity of 20 to 10,000 cP at 23 ° C.

  In (B), the number of mercaptoalkyl groups bonded to the silicon atom in 1 minute is on average 2 or more and 20 from the viewpoint of suppressing excessive curing shrinkage while ensuring a stable structure by the crosslinking reaction. It can be as follows. Among these, more than 2 and 10 or less are preferable, and more preferably 3 to 7.

  In (B), the alkyl portion of the mercaptoalkyl group bonded to the silicon atom can be a C1-C6 alkyl group. Examples of the mercaptoalkyl group include mercaptomethyl, 2-mercaptoethyl, 3-mercaptopropyl, 4-mercaptobutyl, 6-mercaptohexyl and the like. From the viewpoint of ease of synthesis, mercaptomethyl, 3-mercaptopropyl, etc. Is preferred, and 3-mercaptopropyl is more preferred.

  In (B), the organic group other than the mercaptoalkyl group bonded to the silicon atom can be a substituted or unsubstituted monovalent hydrocarbon group (provided not to be an aliphatic unsaturated group). . Specifically, an alkyl group, such as a C1-C6 alkyl group (for example, methyl, ethyl, propyl, etc.); a cycloalkyl group, such as a C3-C10 cycloalkyl group (for example, cyclohexyl, etc.); an aryl group, for example, C6-C12 Aryl (eg, phenyl, tolyl, xylyl, etc.); aralkyl group, eg, C7-C13 aralkyl group (eg, 2-phenylethyl, 2-phenylpropyl, etc.); substituted hydrocarbon group, eg, halogen-substituted hydrocarbon group (eg, Chloromethyl, chlorophenyl, 3,3,3-trifluoropropyl, etc.). An alkyl group is preferable from the viewpoint of easiness of synthesis, etc. Among them, methyl, ethyl and propyl are preferable, and methyl is more preferable. In order to adjust the refractive index, an aryl group can be used in combination, and among them, phenyl is preferable from the viewpoint of ease of synthesis.

The structure of the main chain of (B) may be linear, branched or cyclic, and is preferably branched. For example, R ″ SiO _3/2 units, R ″ ₃ SiO _1/2 units and R ″ ₂ SiO _2/2 units, and optionally further SiO _4/2 units (where R ″ is Each independently composed of an unsubstituted or substituted monovalent hydrocarbon group (provided not to be an aliphatic unsaturated group), 2 or more and 20 or less R ′ per molecule Examples thereof include branched organopolysiloxanes containing mercaptoalkyl groups, wherein 'is a mercaptoalkyl group. Examples of the mercaptoalkyl group and the unsubstituted or substituted monovalent hydrocarbon group include the groups described above. R ″ which is a mercaptoalkyl group may be present as R ″ of any unit, but is preferably present as R ″ of R ″ SiO _3/2 unit. As the mercaptoalkyl group and the unsubstituted or substituted monovalent hydrocarbon group, the above groups can be applied. From the viewpoint of workability and crosslinking reactivity, the ratio of the number of siloxane units containing a mercaptoalkyl group and the number of siloxane units not containing a mercaptoalkyl group is preferably from 1:60 to 1: 8, more preferably 1: 50 to 1:10.

  In (B), the viscosity at 23 ° C. is 20 to 10,000 cP. From the viewpoint of workability and refractive index, for example, the viscosity can be 30 to 8,000 cP.

The number of mercapto groups in (B) can be measured by colorimetric titration with iodine. This is the following formula:
2RSH + I ₂ → RSSR + 2HI
This method utilizes the fact that the titration solution becomes slightly yellow with a small amount of excess iodine during titration.

  (B) is preferably highly transparent. An example of the transparency index (B) is that the transmittance is 80% or more. In order to measure the transmittance of (B), at 23 ° C., (B) was filled in a container, and the transmittance at a visible light region wavelength (360 to 780 nm) was measured with a spectrophotometer for a thickness of 10 mm. taking measurement. The transmittance is preferably 90% or more from the viewpoint that the transparency of the cured product of the composition can be stably maintained.

  The method for preparing (B) is not particularly limited. For example, mercaptopropyltrimethoxysilane, mercaptopropyltriethoxysilane, mercaptopropylmethyldimethoxysilane, mercaptopropylmethyldiethoxysilane, mercaptopropyldimethylmethoxysilane, mercaptopropyldimethylethoxy It can be produced by hydrolysis, polycondensation, and re-equilibration of a mercaptoalkylalkoxysilane such as silane and a desired alkylchlorosilane, alkylalkoxysilane, or silanol-containing siloxane.

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

  The composition contains an acyl phosphine oxide compound selected from the group consisting of (C) 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide. To do. (C) is a component that functions as a radical initiator or a sensitizer when photocrosslinking (A) and (B). (C) may be used alone or in combination.

The composition comprises (D) a benzotriazole compound selected from the group consisting of C ₇ -C ₉ alkyl esters of 3- (2H-benzotriazol-2-yl) -4-hydroxy-5-tert-butylbenzenepropionic acid. Including. (D) functions as a compatibilizer for compatibilizing (C), which is a solid, with (A) and (B) by combining with (E) described later in a specific amount. By blending (D) and (E) to be described later, the composition can be easily separated.

  In the present invention, if any one of (C), (D) and (E) is not compatible with (A) and (B), uneven distribution of incompatible components occurs in the composition, and uniform A liquid UV curable resin composition cannot be obtained. In addition, even when (C), (D) and (E) are compatible, the mixture of (C), (D) and (E) must be compatible with (A) and (B). In this case, a uniform liquid ultraviolet resin composition cannot be obtained. In these cases, uniform curability and UVA resistance of the resulting cured product cannot be exhibited.

(D) may be used alone or in combination of two or more. (D) is preferably 3- (2H-benzotriazol-2-yl) -4-hydroxy-5-tert-butylbenzenepropionic acid C ₇ alkyl ester, 3- (2H-benzotriazol-2-yl) 4-hydroxy -5-tert-butyl-benzenepropanoic acid _{C 8} alkyl ester and 3- (2H-benzotriazol-2-yl) -4-hydroxy -5-tert three butylbenzene acid _{C 9} alkyl esters It is a mixture of compounds (hereinafter, this mixture is also referred to as “3- (2H-benzotriazol-2-yl) -4-hydroxy-5-tert-butylbenzenepropionic acid C ₇ -C ₉ alkyl ester”). .

  The composition comprises (E) bis (1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate And a hindered amine compound selected from the group consisting of methyl-1,2,2,6,6-pentamethyl-4-piperidyl sebacate.

  (E) may be used alone or in combination of two or more. (E) is preferably bis (1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate from the point that a more transparent composition is obtained.

  In the composition, (B) is such that the ratio (HS / Vi) of the number of mercaptoalkyl groups (HS) in (B) to the number of aliphatic unsaturated groups (Vi) in (A) is 0.1-10. Use in an amount of From the viewpoint of curability and the hardness of the cured product, the ratio is preferably 0.3 to 5, and more preferably 0.6 to 2.

  In the composition, (C) is 0.08 to 0.25% by weight in a total of 100% by weight of (A), (B), (C), (D) and (E). If the range of (C) is said range, the solubility in a composition will be obtained easily. Further, if (C) is less than 0.08% by weight in the total of 100% by weight of (A), (B), (C), (D) and (E), the curability of the composition is inferior. If it exceeds 0.25% by weight, the resulting cured product has poor UVA resistance. (C) is preferably 0.09 to 0.22% by weight, more preferably 0.1 to 0.2% by weight, from the viewpoint of improving the curability of the composition and the UVA resistance of the resulting cured product. preferable.

  In the composition, (D) is 0.5 to 5.0% by weight in a total of 100% by weight of (A), (B), (C), (D) and (E). When (D) is less than 0.5% by weight, (C) cannot be dissolved and compatibilized with (A) and (B). Not only is inferior, but also causes the composition to be unnecessarily colored, and the resulting cured product is more markedly colored. (D) is preferably 1.0 to 4.0% by weight from the viewpoint of obtaining a composition in which (C) can be more easily compatibilized and coloring is further suppressed. 3.0 weight% is more preferable.

  (E) may be used alone or in combination of two or more. (E) is 0.1 to 0.5% by weight in a total of 100% by weight of (A), (B), (C), (D) and (E). When (E) is less than 0.1% by weight, the resulting cured product has poor UVA resistance (particularly yellowing), and when it is more than 0.5% by weight, (C), (D) and ( Even if a uniform solution in which E) is compatible is obtained, when this is added to (A) and (B), the occurrence of smudges becomes significant in the composition, and the composition is unnecessarily colored. This causes the optical properties of the cured product obtained thereby. (E) is preferably 0.18 to 0.45% by weight from the viewpoint of obtaining a composition having higher transparency and lowering the yellow index of the resulting cured product. ~ 0.4 wt%.

  The total amount of (D) and (E) is 100% by weight in total of (A), (B), (C), (D) and (E), since (C) can be more compatibilized. The content is preferably 1.0 to 4.5% by weight, more preferably 1.5 to 3.0% by weight. When the total amount of (D) and (E) is 1.0% by weight or more, sufficient UVA resistance is obtained, and (C), (D) and (E) are more uniformly compatible. The transparency of the composition is further improved. Further, if the total amount of (D) and (E) is 4.5% by weight or less, sufficient curability is obtained, the transparency of the composition is further improved, and coloring of the composition is further suppressed. .

  The total weight of (A), (B), (C), (D) and (E) with respect to the total weight of the composition is not particularly limited, and can be, for example, 80 to 100% by weight, It is preferably 90% by weight to 100% by weight.

  The composition of this invention may contain the polyorganosiloxane containing aliphatic unsaturated groups other than (A) component in the range which does not impair the effect of this invention. Such a polyorganosiloxane containing an aliphatic unsaturated group may be linear or branched.

  As a linear thing, the linear polyorganosiloxane containing an aliphatic unsaturated group which does not contain a phenyl group is mentioned, for example, For example, the polydimethylsiloxane containing both terminal vinyl groups is mentioned. Such a linear polyorganosiloxane can have a viscosity at 23 ° C. of 100 to 100,000 cP, preferably 100 to 25,000 cP, and 200 to 10, from the viewpoint of workability of the composition. 000 cP is more preferable, and 300 to 5,000 cP is still more preferable.

Examples of the branched ones include M ^Vi Q resin, MD ^Vi Q resin, M ^Vi T resin, M ^Vi DT resin, MD ^Vi T resin, and the like. Here, the M unit is a (CH ₃ ) ₃ SiO _1/2 — unit, M ^Vi is a (CH ₂ ═CH) (CH ₃ ) ₂ SiO _1/2 — unit, and D is − ( CH ₃ ) ₂ SiO _2/2 — units, D ^Vi is — (CH ₃ ) (CH ₂ ═CH) SiO _2/2 — units, and T is (CH ₃ ) SiO _3/2 ≡ units. And Q is SiO _4/2 units (tetrafunctional).

Specifically, SiO _4/2 units, R ′ ₃ SiO _1/2 units and R ′ ₂ SiO _2/2 units, and optionally further R′SiO _3/2 units (wherein R ′ is A branched organopolysiloxane, which independently represents a C1 to C6 alkyl group or an aliphatic unsaturated group), and has at least three R ′ per molecule an aliphatic unsaturated group. Among them, a branched organopolysiloxane having a ratio of 6 to 10 mol of SiO _4/2 units and 4 to 8 mol of R ′ ₃ SiO _1/2 units with respect to 1 mol of R ′ ₂ SiO _2/2 units. Can be mentioned. The polyorganosiloxane containing an aliphatic unsaturated group other than the component (A) is preferably a solid or viscous semi-solid resinous or liquid at room temperature. Examples include those having a weight average molecular weight of 1,000 to 400,000, preferably 2,000 to 200,000. The weight average molecular weight is a value obtained by using polystyrene as a calibration curve by gel permeation chromatography (GPC).

As the aliphatic unsaturated group related to R ′, the groups and preferred groups mentioned as the aliphatic unsaturated group in (A) are applied. R ′ which is an aliphatic unsaturated group may be present as R ′ of any unit, but is preferably present as R ′ of the R ′ ₂ SiO unit.

  R ′ other than the aliphatic unsaturated group is a C1-C6 alkyl group (for example, methyl, ethyl, propyl, etc.), and a methyl group is preferable in consideration of heat resistance.

  The composition may contain additives such as a silane coupling agent, a polymerization inhibitor, and an inorganic filler as long as the effects of the present invention are not impaired. The composition preferably does not contain acetophenone and propiophenone. Acetophenone and propiophenone are components that accelerate the increase in the yellow index of the cured product by UVA exposure. Therefore, UVA resistance of the hardened | cured material obtained improves more because a composition does not contain acetophenone and propiophenone.

  Examples of silane coupling agents include 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-aminopropyltriethoxysilane, and 3-aminopropyltrimethoxysilane. 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, trimethoxysilylpropyldiallyl isocyanurate, bis (trimethoxysilyl) Propyl) allyl isocyanurate, tris (trimethoxysilylpropyl) isocyanurate, triethoxysilylpropyldiallyl isocyanurate, bis (triethoxysilylpro) Le) allyl isocyanurate, include tris (triethoxysilylpropyl) isocyanurate, preferably 3-methacryloxypropyl triethoxy silane, 3-methacryloxypropyl trimethoxy silane.

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

  The inorganic filler can be used for adjusting the fluidity of the composition and adjusting the physical properties after curing, and examples thereof include fumed silica, pulverized quartz, and metal oxide.

  From the viewpoint of workability, the composition preferably has a viscosity at 23 ° C. of 100 to 50,000 cP, more preferably 100 to 10,000 cP, and still more preferably 500 to 3,000 cP. .

  A composition can be obtained by mix | blending (A)-(E) and an arbitrary component. In preparation, a solution of (D) and (E) is prepared and (C) is dissolved in this, since the composition can be easily made uniform and a transparent cured product can be obtained. The resulting solution is preferably added to and mixed with the mixture containing (A) and (B) to obtain a uniform composition. Optional components can be added as appropriate.

The composition can be cured by irradiation with ultraviolet light. Irradiation dose is preferably 100~10,000mJ / cm ^2, more preferably 300~6,000mJ / cm ^2, more preferably from 500~4,000mJ / cm ^2. The irradiation amount is a measured value of UVA. Here, UVA refers to ultraviolet rays in the range of 315 to 400 nm.

  The composition has good curability when irradiated with ultraviolet rays having an ultraviolet wavelength, for example, a range of 250 to 450 nm. As a light source that emits ultraviolet light having such a wavelength, for example, a high pressure mercury lamp (UV-7000) manufactured by Ushio Electric Co., Ltd., a metal halide lamp (UVL-4001M3-N1), Korea: a metal halide lamp manufactured by JM tech (JM) -MTL 2KW), Mitsubishi Electric Corporation ultraviolet irradiation lamp (OSBL360), Nippon Battery Co., Ltd. ultraviolet irradiation machine (UD-20-2), Toshiba Corporation fluorescent lamp (FL-20BLB)), Heraeus H valve, H plus valve, V valve, D valve, Q valve, M valve, etc. manufactured by the company are listed.

  The cured product of the composition has good UVA resistance. Therefore, even after being cured, even when exposed to ultraviolet rays in the UVA region including sunlight, yellowing can be suppressed and a cured product having a small haze value can be provided, which is assumed from the usage environment of the image display device. The yellowing due to the influence of the light and the increase in haze are suppressed, and the visibility of the image display device can be maintained in a good state.

  The composition can be used as a sealant for an image display device. A sealant for an image display device can be interposed between the image display unit and the protection unit, and cured by irradiation with ultraviolet rays to seal the image display unit and the protection unit.

  The composition can be suitably used in an image display device, and is particularly preferable as a resin interposed between a protective portion and an image display portion of a flat panel image display device. Specifically, after applying the composition on the protective panel constituting the transparent protective part formed of optical plastic or the like, the image display panel constituting the image display part may be bonded and irradiated with ultraviolet rays. it can. The protective panel may be provided with a step for preventing the composition of the present invention from flowing out at the outer peripheral edge.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited by these examples.

[Evaluation conditions for physical properties]
(1) Viscosity Using a rotational viscometer (Bismetron VDA-L) (manufactured by Shibaura System Co., Ltd.), the range of 400 cP or less is No. 2 rotors are used, and the range of more than 400 to 1500 cP is No. 3 rotors are used, and the range over 1,500 cP is No. Using 4 rotors, the viscosity at 23 ° C. was measured at 60 rpm.

(2) Measurement of the number of mercapto groups A 1/10 normal iodine solution (special grade reagent) was used as an iodine source, and the number of mercapto groups per unit weight was determined by colorimetric titration.
Calculation method: SH content (mmol / g) = (A × P × 0.1) / (W × C)
A: Iodine solution dripping amount required until color change P: Correction coefficient of iodine solution (correction coefficient described in reagent): Described when correction is required W: Sample weight (g)
C: Nonvolatile content of sample Preliminary measurement was performed to determine the amount of iodine solution, and then measured three times with high accuracy to obtain an average value of three times.

(3) Measurement of ultraviolet irradiation amount The irradiation amount of UVA (315 to 400 nm) in an ultraviolet light source was measured using an ultraviolet light meter UV-350 manufactured by Oak Manufacturing Co., Ltd.

(4) Qualitative appearance evaluation of uncured material In a yellow room, the prepared composition was transferred to a 50 ml capacity glass bottle, and the appearance was evaluated by a method of visually confirming the presence or absence of insoluble matter and scum.

(5-1) Qualitative curing evaluation 1
Two glass plates with a thickness of 1.1 mm were used. One glass plate was light-shielded entirely on the opposite side of the adherend using black PVC tape. Two glass plates were bonded so that the composition had a size of 20 mm × 10 mm and a thickness of 150 μm. Next, light from a metal halide lamp (UVL-4001M3-N1 manufactured by Ushio Electric Co., Ltd.) was irradiated from the unshielded side to prepare a shear test specimen. Immediately after the preparation of the shear test specimen, a tensile test was carried out with a tensile tester (AG-IS type) manufactured by Shimadzu Corporation at a tensile speed of 10 mm / min. The curability was evaluated by a method of confirming the cured state of the composition in each shear specimen by visual observation and finger touch.
UV energy irradiation amount UVA: 3,000 mJ / cm ²

(5-2) Qualitative curing evaluation 2
The curability was evaluated in the same manner as in the qualitative curing evaluation 1 by changing the irradiation amount of ultraviolet energy to the following amounts.
UV energy irradiation amount UVA: 6,000 mJ / cm ²

(5-3) Qualitative curing evaluation 3
The curability was evaluated in the same manner as in the qualitative curing evaluation 1 by changing the irradiation amount of ultraviolet energy to the following amounts.
UV energy irradiation amount UVA: 10,000 mJ / cm ²

(5-4) Qualitative curing evaluation 4
The curability was evaluated in the same manner as in the qualitative curing evaluation 1 by changing the irradiation amount of ultraviolet energy to the following amounts.
UV energy irradiation amount UVA: 20,000 mJ / cm ²

(6) Adhesion to glass (cohesive failure rate%)
Two glass plates with a thickness of 1.1 mm were used. One glass plate was light-shielded entirely on the opposite side of the adherend using black PVC tape. Two glass plates were bonded so that the composition had a size of 20 mm × 10 mm and a thickness of 150 μm. Next, light from a metal halide lamp (UVL-4001M3-N1 manufactured by Ushio Electric Co., Ltd.) was irradiated from the unshielded side to prepare a shear test specimen. Immediately after the preparation of the shear test specimen, a tensile test was carried out with a tensile tester (AG-IS type) manufactured by Shimadzu Corporation at a tensile speed of 10 mm / min.
UV energy irradiation amount UVA: 6,000 mJ / cm ²
Obtain the area Smm ² of the cohesive failure portion of the ultraviolet curable resin composition on the glass,
(100 × S) / (10 × 20)
Was calculated as the cohesive failure rate (%).

(7) Yellow index Two glass plates with a thickness of 1 mm were used. Two glass plates were bonded so that the composition had a size of 50 mm × 50 mm and a thickness of 180 μm. Subsequently, the sample was produced by irradiating the light from a metal halide lamp (UVL-4001M3-N1 manufactured by USHIO INC.).
UV energy irradiation amount UVA: 6,000 mJ / cm ²
Using the measurement device CM-3500d (manufactured by Konica Minolta Co., Ltd.) and the Q-Lab environmental tester manufactured by Q-Lab, whose light source is UVA-340, the radiation intensity of 0.89 W / m ² / nm is measured. The yellow index (ASTM D1925) of the sample after 200 hours of treatment was measured. UVA-340 is an ultraviolet lamp that faithfully reproduces a wavelength range from 295 nm to 365 nm, which is a short wavelength range of sunlight. As an index showing good UVA resistance, the yellow index value was less than 1.0.

(8) Haze A sample was prepared in the same manner as “(7) Yellow index”.
About the produced sample, based on JISK7105, using a haze meter NDH5000 (manufactured by Nippon Denshoku Industries Co., Ltd.), a radiant intensity of 0 with a Q-Lab environmental tester manufactured by Q-Lab, whose light source is UVA-340 The haze of the sample after 200 hours of treatment at 89 W / m ² / nm was measured. As an index showing good UVA resistance, the haze value was less than 1.0.

(9) Presence / absence of bubbles generated A sample was prepared in the same manner as in “(7) Yellow index”.
For the prepared sample, the sample after processing for 200 hours at a radiation intensity of 0.89 W / m ² / nm using a Q-UV environmental tester manufactured by Q-Lab with the light source as UVA-340 The presence or absence of generation was confirmed visually.

(A) component in an Example and a comparative example is as follows.
(A) Both ends vinyl polyphenylmethylsiloxane (a-1): Both ends vinyl polyphenylmethylsiloxane (phenyl 5%, viscosity 20,000 cP)
Average number of aliphatic unsaturated groups in one molecule: 2
Average unit _{formula: CH 2 = CH-Si (} CH 3) 2 -O- {Si (CH 3) 2 O} 618 - {SiPh 2 O} 32 -Si (CH 3) 2 -CH = CH 2
Molecular weight: 52,323, number of vinyl groups per unit weight: 0.038 mmol / g
(A-2): Vinyl polyphenylmethylsiloxane at both ends (phenyl 5%, viscosity 3,000 cP)
Average number of aliphatic unsaturated groups in one molecule: 2
Average unit _{formula: CH 2 = CH-Si (} CH 3) 2 -O- {Si (CH 3) 2 O} 335 - {SiPh 2 O} 18 -Si (CH 3) 2 -CH = CH 2
Molecular weight: 28,639, number of vinyl groups per unit weight: 0.07 mmol / g
(A-3): Vinyl polyphenylmethylsiloxane at both ends (phenyl 5%, viscosity 1,000 cP)
Average number of aliphatic unsaturated groups in one molecule: 2
Average unit _{formula: CH 2 = CH-Si (} CH 3) 2 -O- {Si (CH 3) 2 O} 177 - {SiPh 2 O} 9 -Si (CH 3) 2 -CH = CH 2
Molecular weight: 15,085, number of vinyl groups per unit weight: 0.133 mmol / g

(A-1) was synthesized as follows.
A 1 L 1,1,3,3,5,5,7,7-octamethylcyclotetrasiloxane was added to a 3 L separable flask equipped with a cooling reflux tube and a three-one motor as a stirrer, 1,1,3,3. , 5,5,7,7-octaphenylcyclotetrasiloxane 259 g, 1,1,3,3-tetramethyl-1,3-divinyldisiloxane 7.5 g at 150-160 ° C. with nitrogen gas 0.5 Nm ³ Dehydration was performed by heating and stirring at / h for 3 hours, and then 0.1 g of potassium hydroxide was added and heating and stirring was performed. Heating and stirring dissolves potassium hydroxide in the flask and makes it uniform. Solid 1,1,3,3,5,5,7,7-octaphenylcyclotetrasiloxane disappears by ring-opening polymerization. It lasted about 8 hours until the product equilibrated. The viscosity at this time was 14,000-17,000 cP. Then, after neutralizing at 100 ° C. with 10 g of ethylene chlorohydrin and filtering using super celite floss as a filter aid, the low boiling point is removed under reduced pressure of 170 to 180 ° C. and 2 mmHg. Thus, 1880 g of vinyl-terminated polymethylphenylsiloxane whose end was blocked with a dimethylvinylsiloxy group, 5 mol% of diphenylsiloxy units, and the remainder was dimethylsiloxy units was obtained.

  (A-2) is 1,1,3,3,5,5,7,7-octamethylcyclotetrasiloxane 1840 g, 1,1,3,3,5,5,7,7-octaphenylcyclotetra Except that 260 g of siloxane and 13.6 g of 1,1,3,3-tetramethyl-1,3-divinyldisiloxane were used and the heating and stirring was continued until the viscosity increased to 2,000-2500 cP. , (A-1).

  (A-3) is 1,1,3,3,5,5,7,7-octamethylcyclotetrasiloxane 1840 g, 1,1,3,3,5,5,7,7-octaphenyl With the exception that 254 g of cyclotetrasiloxane and 26.1 g of 1,1,3,3-tetramethyl-1,3-divinyldisiloxane were used and heating and stirring was continued until the viscosity increased to 700-850 cP, It was produced in the same manner as (a-1).

(B) component in an Example and a comparative example is as follows.
(B) Mercaptopropyl group-containing polymethylsiloxane Viscosity: 300 cP
Number of mercapto groups per unit weight: 0.98 mmol / g
(B) was synthesized as follows.
1549.2 g (12 mol) of dimethyldichlorosilane, 21.7 g (0.2 mol) of trimethylchlorosilane, 3-mercaptopropyltrimethyl in a 5 L separable flask equipped with a three-motor as a reflux tube, a dropping funnel and a stirring device To 196.4 g (1.0 mol) of methoxysilane and 1500 g of toluene, a mixture of 1000 g of water and 500 g of toluene was dropped from a dropping funnel over about 1 hour. Hydrolysis was performed with heating and stirring at 70 ° C. for 2 hours. After completion of the reaction, the aqueous phase was separated, washed with water, and then dehydrated by heating at 100 to 125 ° C. After completion of the dehydration, 1.5 g of a 50% aqueous potassium hydroxide solution was added, and a condensation reaction was performed by heating and stirring at 115 to 125 ° C. for 5 hours. After neutralization with ethylene chlorohydrin, 1200 to 1300 g of toluene is dissolved and filtered using super celite floss as a filter aid, and then the remaining toluene is removed under normal pressure and reduced pressure to form silicon atoms. 928 g of polymethylsiloxane containing a mercaptopropyl group to be bonded was obtained.

(C) component in an Example and a comparative example is as follows.
(C-1) Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (c-2) 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide

(D) component in an Example and a comparative example is as follows.
(D-1) 3- (2H- benzotriazol-2-yl) -4-hydroxy -5-tert-butylbenzene acid _C 7 -C ₉ alkyl esters (BASF Corp., Tinuvin384-2)

(E) component in an Example and a comparative example is as follows.
(E-1) Bis (1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate (manufactured by BASF, Tinuvin 123)
(E-2) A mixture of bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate (manufactured by BASF, Tinuvin 765)

Other components in Examples and Comparative Examples are as follows.
Other silicone (1): vinyl polydimethylsiloxane at both ends (viscosity 10,000 cP)
Other silicone (2): M units _{((CH 3) 3 SiO 1/2} - units), ^{D v} units _{(- (CH 3) (CH} 2 = CH) SiO- units) and Q units _{(SiO 4/2} ( Branched polymethylvinylsiloxane having a molar unit ratio of M ₆ D ^v Q ₈ and other silicones (3): M units ((CH ₃ ) ₃ SiO _1/2 -units) and Branched polymethylsiloxane _{composed of} Q units (SiO _4/2 (tetrafunctional) units) and having a molar unit ratio of MQ Polymerization inhibitor: pt-butylcatechol Silane coupling agent: 3-methacryloxypropyl Trimethoxysilane Other benzotriazole (1): 2- (5-chloro-2-benzotriazolyl) -6-tert-butyl-p-cresol (manufactured by BASF, Tinuv n326)
Other benzotriazole (2): 2- (2H-benzotriazol-2-yl) -6- (1-methyl-1-phenylethyl) -4- (1,1,3,3-tetramethylbutyl) phenol (BASF, Tinuvin 928)
Other photoinitiator (1): 2-hydroxy-2-methyl-1-phenyl-propan-1-one (BASF, Darocur 1173)
Other photoinitiators (2): 2,2-dimethoxy-1,2-diphenylethane-1-one (Irgacure 651, manufactured by BASF)

The preparation method of the composition of an Example and a comparative example is as follows.
(Preparation of base composition)
Among the components described in the base composition of Table 1, (a-1) to (a-3), other silicones (1) to other silicones (3), (b), and a polymerization inhibitor are all-purpose kneaded. The mixture was stirred and mixed with a machine to obtain a uniform composition. A silane coupling agent was added thereto and mixed with a polypropylene cup and a metal spatula to obtain a uniform composition, which was used as a base composition.
[Addition of additional ingredients]
The additional components listed in Table 1 are heated to 60 ° C. in a closed container and stirred repeatedly to make a uniform solution, which is added to the base composition and mixed with a polypropylene cup and a metal spatula to form a uniform composition. The composition of the Example and the comparative example was prepared by obtaining a thing. The physical properties of the composition were evaluated. Table 2 shows the results. The numerical values in Table 1 are based on weight.

Each composition of the Examples had a yellow index value and a haze value after the UVA test of the resulting cured product of less than 1.0, and was excellent in UVA resistance. In particular, Examples 1 to 5 were all transparent compositions. In Example 6, fogging was observed, but there was no obvious insoluble precipitate, and it did not separate over time, and was a uniform liquid composition.
In Comparative Example 1, since the amount of (C) is more than 0.25% by weight, the resulting cured product has a yellow index value and a haze value after UVA test of more than 1.0, and is inferior in UVA resistance. It was. Comparative Example 2 was inferior in curability because the amount of (C) was less than 0.08% by weight. Since Comparative Example 3 did not contain (E), the resulting cured product had a high yellow index after the UVA resistance test and was inferior in UVA resistance. Since both Comparative Examples 4 and 5 did not contain (D) and contained a benzotriazole compound other than (D), insolubles were precipitated and were not uniform liquid compositions. Since Comparative Example 6 did not contain (D) and (E), the resulting cured product had a high yellow index after the UVA resistance test, bubbles were formed, and the UVA resistance was poor.

  ADVANTAGE OF THE INVENTION According to this invention, the ultraviolet curable silicone resin composition which provides the hardened | cured material which has the outstanding UVA resistance is provided. The composition can be suitably used for a member that is easily damaged by ultraviolet rays. For example, in the production of an image display device that requires good UVA resistance, such as being expected to be used outdoors, It is suitable for sealing applications between the protective part and the image display part.

Claims (5)

(A) Formula (I):

(Where
Each R ¹ is independently an aliphatic unsaturated group;
Each R is independently a C1 to C6 alkyl group or a C6 to C12 aryl group, and 1 to 40 mol% of R is a C6 to C12 aryl group,
n is a number having a viscosity at 23 ° C. of 100 to 100,000 cP), and a linear polyorganosiloxane containing an aliphatic unsaturated group;
(B) a polyorganosiloxane containing a mercaptoalkyl group bonded to a silicon atom, having a viscosity at 23 ° C. of 10 to 10,000 cP;
(C) an acylphosphine oxide compound selected from the group consisting of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide; and (D) 3 - (2H-benzotriazol-2-yl) -4- _C 7 ~C ₉ benzotriazole compounds chosen from the group consisting of alkyl esters of hydroxy -5-tert-butyl-benzenepropanoic acid; and (E) bis (1- Octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and methyl-1,2,2,6 A hindered amine compound selected from the group consisting of 6-pentamethyl-4-piperidyl sebacate Hints, here,
The ratio of the number of mercaptoalkyl groups in (B) to the number of aliphatic unsaturated groups in (A) is 0.1 to 10,
Of the total 100% by weight of (A) to (E), (C) is 0.08 to 0.25% by weight, (D) is 0.5 to 5.0% by weight, and (E) is 0.1 to 0.5% by weight,
UV curable silicone resin composition.   The ultraviolet curable silicone resin composition according to claim 1, wherein (E) is bis (1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate.   Furthermore, the ultraviolet curable silicone resin composition of Claim 1 or 2 containing a silane coupling agent.   The sealing compound for image display apparatuses which consists of an ultraviolet curable silicone resin composition of any one of Claims 1-3.   An image display device in which an image display unit and a protection unit are sealed using the sealant for an image display device according to claim 4.