JP2020045387A - Curable composition, cured product, and optical member - Google Patents

Abstract

To provide a curable composition whose cured product is capable of maintaining excellent optical characteristics even when exposed to a high temperature for a long period of time or irradiated with ultraviolet rays for a long period of time.SOLUTION: The curable composition contains: a silsesquioxane compound having a structure represented by RSiOand a structure represented by (R)SiO(Ris an aryl group, an alkyl group or a hydrogen atom, and Ris an aryl group or an alkyl group); and a siloxane compound having a structure represented by RXSiOor both this structure and a structure represented by (R)SiO(Ris an aryl group or an alkyl group, and X is a hydroxyl group or a hydrolyzable group).SELECTED DRAWING: None

Description

  The present invention relates to a curable composition, a cured product, and an optical member.

  For optical members such as optical semiconductor elements, materials having excellent heat resistance and transparency are used. As a material related to such an application, Patent Document 1 discloses a curable resin composition containing a specific polyorganosiloxane, a specific silsesquioxane, an isocyanurate compound, and a silane coupling agent. .

International Publication No. WO 2014/109349

  However, the cured product of the conventional curable composition causes peeling from the adherend and changes in optical properties when used at a high temperature for a long period of time or when exposed to ultraviolet light (UV). There was a limit to its application.

  Therefore, an object of the present invention is to provide a curable composition that can maintain excellent optical properties even when the cured product is exposed to a high temperature for a long period of time or is subjected to ultraviolet irradiation for a long period of time. It is in.

下記式（２ａ）、又は、下記式（２ａ）及び（２ｂ）で表される構造を有するシロキサン化合物（以下、「化合物（ＩＩ）」と呼ぶ場合がある。）と、を含有する硬化性組成物を提供する。なお、式中「＊」は結合手を意味する（以下同様）。 The present invention relates to a silsesquioxane compound having a structure represented by the following formulas (1a) and (1b) (hereinafter sometimes referred to as “compound (I)”).

A curable composition containing the following formula (2a) or a siloxane compound having a structure represented by the following formulas (2a) and (2b) (hereinafter sometimes referred to as “compound (II)”). Offer things. In the formula, “*” means a bond (the same applies hereinafter).

［式中、Ｒ^１１はアリール基、アルキル基又は水素原子、Ｒ^１２は水素原子、アリール基又はアルキル基、Ｒ^２１はアリール基又はアルキル基、Ｘは水酸基又は加水分解性基、ｎは２〜１００の数、をそれぞれ表す。但し、複数存在するＲ^１１、Ｒ^１２、Ｒ^２１及びＸはそれぞれ同一でも異なっていてもよく、Ｒ^１１のうち少なくとも一つはアリール基である。］

[In the formula, R ¹¹ is an aryl group, an alkyl group or a hydrogen atom, R ¹² is a hydrogen atom, an aryl group or an alkyl group, R ²¹ is an aryl group or an alkyl group, X is a hydroxyl group or a hydrolyzable group, and n is 2 to 2. 100 number, respectively. However, a plurality of R ¹¹ , R ¹² , R ²¹ and X may be the same or different, and at least one of R ¹¹ is an aryl group. ]

  According to the present invention, it is possible to provide a curable composition in which excellent optical characteristics are maintained even when a cured product is exposed to a high temperature for a long period of time or is irradiated with ultraviolet rays for a long period of time. .

  Hereinafter, embodiments of the present invention will be described.

  The curable composition according to the example contains (I) a silsesquioxane compound (compound (I)) and (II) a siloxane compound (compound (II)).

  Compound (I) may have at least one selected from the group consisting of a hydroxyl group and a hydrolyzable group bonded to a silicon atom. When the compound (I) has these atoms or groups, a siloxane bond (—Si—O—Si—) can be formed by a reaction such as hydrolysis or condensation, so that the compound (I) is a reactive compound. Becomes

  Examples of the hydrolyzable group include a halogen atom, an alkoxy group, an acyloxy group, an alkenyloxy group, an amino group, a ketoximate group, an aminooxy group, a carbamoyl group, and a mercapto group. Among them, an alkoxy group is preferable. Examples of the alkoxy group include an alkoxy group having 1 to 6 carbon atoms, and a methoxy group and an ethoxy group are preferable from the viewpoint of reactivity. The meaning and preferred examples of the hydrolyzable group in the present invention are the same as described above for other compounds and structures.

Compound (I) has a structure represented by the following formula (1a) (hereinafter sometimes referred to as “structure 1a”). That is, the compound (I) is a silsesquioxane compound because it has a T unit in which one organic component and three oxygen atoms are bonded to a silicon atom and has a basic skeleton of (R ¹¹ -SiO _1.5 ). Corresponds to.

R ¹¹ is an aryl group, an alkyl group or a hydrogen atom, and examples of the aryl group include a phenyl group and a substituted phenyl group. Examples of the substituent of the phenyl group include an alkyl group and an alkenyl group. As the aryl group, a phenyl group is preferable. The alkyl group for R ¹¹ may be linear, branched or cyclic. The number of carbon atoms in the alkyl group may be, for example, 1 to 10, and is preferably 1 to 8, more preferably 1 to 6, and still more preferably 1 to 4 because of excellent condensation reactivity. Examples of the alkyl group for R ¹¹ include a methyl group, an ethyl group, a propyl group (n-propyl group, isopropyl group), a butyl group (n-butyl group, sec-butyl group, isobutyl group, tert-butyl group) and the like. Is mentioned. The alkyl group for R ¹¹ is preferably a methyl group or an ethyl group, and more preferably a methyl group.

In the compound (I), at least one of a plurality of R ¹¹ is an aryl group, and among all the structures 1a constituting the compound (I), of the structure 1a in which R ¹¹ is an aryl group. The ratio may be, for example, 5 mol% or more, and is preferably 10 mol% or more, more preferably 30 mol% or more, since the mechanical properties of the cured product are further improved. The upper limit of the ratio of the aryl group to the plurality of R ¹¹ may be, for example, 100 mol%.

The compound (I) has a structure represented by the following formula (1b) (hereinafter sometimes referred to as “structure 1b”) in addition to a structure represented by the formula (1a). Therefore, compound (I) has a siloxane skeleton. That is, the compound (I) is a compound having a silsesquioxane skeleton and a siloxane skeleton.

R ¹² is a hydrogen atom, an aryl group or an alkyl group, and the meaning and preferred examples of these groups are the same as those of R ¹¹ . In addition, a plurality of R ¹² may be the same or different.

In Structure 1b, the combination of R ¹² bonded to the same silicon atom is arbitrary. For example, both may be a hydrogen atom, an alkyl group or an aryl group. One may be an alkyl group and the other may be an aryl group. Further, the structure 1b in which both R ¹² are an alkyl group and the structure 1b in which both R ¹² are an aryl group may coexist. n ranges from 2 to 100. n is preferably 2 to 50, more preferably 2 to 30, especially 2 to 20.

Compound (I) may further have a structure represented by the following formula (1c) (hereinafter sometimes referred to as “structure 1c”). R ¹³ is an aryl group or an alkyl group. Preferred examples and significance of these groups are the same as R ^11. Note that a plurality of R ¹³ may be the same or different. By having such a structure, the storage stability of the curable composition becomes more excellent.

Compound (I) may have a structure represented by the following formula (1d) (hereinafter, may be referred to as “structure 1d”) in addition to the above structures 1a and 1b.

  That is, the compound (I) may be composed of only the structures 1a and 1b, or may have at least one structure of the structures 1c and 1d in addition thereto. The ratio of the structure 1b to the entire structures 1a and 1b is preferably 1 to 12 mol%, more preferably 2 to 10 mol%. Within the above range, high heat resistance can be maintained while sufficiently maintaining flexibility. The ratio of the structure 1c to the entire structures 1a, 1b, and 1c is preferably 3 to 50 mol%, more preferably 5 to 50 mol%, and still more preferably 3 to 30 mol%. By setting the content within the above range, occurrence of gelation during synthesis can be prevented, and storage stability can be improved.

  When the compound (I) contains the structure 1d, the upper limit of the ratio of the structure 1d to the entire structure is, for example, 50 mol%. When the compound (I) has a structure other than the structures 1a and 1b, the ratio of the structure 1a to the entire structure may be, for example, 10 mol% or more, preferably 20 mol% or more, more preferably 30 mol%. That is all. The upper limit may be, for example, 97 mol% or less.

  The structures 1a, 1c, and 1d are also called a T unit, an M unit, and a Q unit, respectively. Structure 1b can also be referred to as an organosiloxane unit. Therefore, the compound (I) is a compound composed of only the T unit and the organosiloxane unit, or having at least one of the M unit and the Q unit in addition to the T unit and the organosiloxane unit.

Compound (I) has a composition formula, for example,
^{_{[ArSiO 3/2] x [R 11}} SiO 3/2] y [R 12 2 SiO 2/2] z
^{_{[ArSiO 3/2] x [R 11}} SiO 3/2] y [R 12 2 SiO 2/2] z [R 13 3 SiO] w
Can be expressed as It is Ar wherein an aryl group, preferable examples and the significance are the same as in R ^11. Further, x, y, z and w are numbers that add up to 1 in the same composition, and represent the molar ratio of each unit.

  The compound (I) may have various shapes such as a ladder type, a cage shape and an amorphous shape as the whole structure. Further, as the partial structure of compound (I), structures represented by the following formulas (11) to (15) are possible. These structures show a case where the aryl group is a phenyl group and the alkyl group is a methyl group.

Compound (I) may be a reactant of silicon compounds (i) and (ii) or a reactant of silicon compounds (i), (ii) and (iii) shown below.
Silicon compound (i): silane having three hydroxyl groups and / or hydrolyzable groups and one aryl group bonded to a silicon atom,
Silicon compound (ii): Silicone having two or more hydroxyl groups and / or hydrolyzable groups bonded to silicon atoms Silicon compound (iii): Hydrosilane having three hydroxyl groups and / or hydrolyzable groups bonded to silicon atoms

Compound (I) can also be a reactant of silicon compounds (i), (ii) and (iv), a reactant of silicon compounds (i), (ii) and (v), a silicon compound (i), (ii) , (Iii) and (iv), silicon compounds (i), (ii), (iii) and (v), silicon compounds (i), (ii), (iii) and (iv) And the reactants of (v).
Silicon compound (iv): silsesquioxane in which a hydroxyl group and / or a hydrolyzable group is bonded to a silicon atom Silicon compound (v): three alkyl groups and / or aryl groups, a hydroxyl group and / or a hydrolyzable group One, silane bonded to silicon atom

The silicon compounds (i), (ii), (iii), (iv) and (v) are represented, for example, by the following formulas (21), (22), (23), (24) and (25), respectively. Can be. Here, R ¹¹ , R ¹² and R ¹³ have the same meaning as described above, Ar represents an aryl group, and X represents a hydroxyl group or a hydrolyzable group. M represents a number of 1 or more, and 1 represents a number of 0 or more. The meanings and preferred examples of the aryl group and the hydrolyzable group are as defined above. A plurality of R ¹¹ , R ¹² , R ¹³ , Ar and X may be the same or different.

  Compound (I) can be synthesized, for example, by hydrolytic condensation of the silicon compound (monomer component). The suitable molecular weight of the silicon compound represented by the formula (22) is 300 to 2,000 when 1 is 0, and more preferably 400 to 1,000. When 1 is not 0, 300 to 8000 is preferable, and 400 to 7000 is more preferable.

  At the time of hydrolytic condensation of the silicon compound, a catalyst may be used. The catalyst may be used as it is, but is usually used in an aqueous solution. Examples of the catalyst include an acid catalyst, an alkali catalyst, and a metal chelate compound.

  Examples of the acid catalyst include organic acids and inorganic acids. Examples of organic acids include formic acid, maleic acid, fumaric acid, phthalic acid, malonic acid, succinic acid, tartaric acid, malic acid, lactic acid, citric acid, acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, and heptanoic acid Octanoic acid, nonanoic acid, decanoic acid, oxalic acid, adipic acid, sebacic acid, butyric acid, oleic acid, stearic acid, linoleic acid, linoleic acid, salicylic acid, benzenesulfonic acid, benzoic acid, p-aminobenzoic acid, 2- Examples include ethylhexanoic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid, p-toluenesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, and trifluoroethanesulfonic acid. Examples of the inorganic acid include hydrochloric acid, phosphoric acid, nitric acid, boric acid, sulfuric acid, hydrofluoric acid and the like. One type of acid catalyst may be used alone, or two or more types may be used in combination.

  Examples of the alkali catalyst include an inorganic base and an organic base. Examples of the inorganic base include ammonia, sodium hydroxide, potassium hydroxide and the like. As the organic base, for example, pyridine, pyrrole, piperazine, pyrrolidine, piperidine, picoline, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monopropylamine, dipropylamine, tripropylamine, monobutylamine, dibutylamine Butylamine, tributylamine, monoethanolamine, diethanolamine, dimethylmonoethanolamine, monomethyldiethanolamine, triethanolamine, diazabicyclooctane, diazabicyclononane, diazabicycloundecene, tetramethylammonium hydroxide and the like. As the alkali catalyst, one kind may be used alone, or two or more kinds may be used in combination.

  Examples of the metal chelate compound include a titanium chelate compound, a zirconium chelate compound, and an aluminum chelate compound. One type of metal chelate compound may be used alone, or two or more types may be used in combination.

  The hydrolytic condensation of the silicon compound may be performed in a solvent. Examples of the solvent include aromatic solvents such as benzene, toluene, and xylene; alcohol solvents such as methanol, ethanol, and 2-propanol; ketone solvents such as acetone and methyl ethyl ketone; and ethylene glycol methyl ether and ethylene glycol ethyl ether. Examples include ether solvents, and ester solvents such as methyl lactate, ethyl lactate, n-butyl lactate, and n-amyl lactate. These may be used alone or in combination of two or more.

  The compound (I) is synthesized, for example, by adding water containing a catalyst to a solution in which a silicon compound is dissolved in a solvent, hydrolyzing the solution, and subjecting it to a condensation reaction. In the case of using a plurality of silicon compounds, if there is a difference in the hydrolysis rate depending on the type, after hydrolyzing the silicon compound having a low hydrolysis rate first, adding a silicon compound having a high hydrolysis rate. A co-condensation reaction may be performed.

  The reaction temperature at the time of hydrolysis and condensation reaction may be from room temperature (25 ° C.) to 100 ° C., and the reaction time varies depending on conditions such as the reaction temperature, but is usually 4 to 24 hours. In addition, alcohol is by-produced during the hydrolytic condensation of the silicon compound. After completion of the reaction, the alcohol can be removed together with the solvent using a vacuum concentrator such as an evaporator.

  The weight average molecular weight (Mw) of the compound (I) is preferably from 500 to 7000, and more preferably from 500 to 4,000 because of excellent handleability of the curable composition. The Mw of the compound (I) is a value measured by GPC (gel permeation chromatography) and converted to standard polystyrene.

  The curable composition according to the embodiment contains the compound (II) in addition to the compound (I) described above.

  The compound (II) has a structure represented by the formula (2a) (hereinafter, may be referred to as “structure 2a”) or a structure represented by structures 2a and 2b (hereinafter, “structure 2b”). ), And has a hydroxyl group or a hydrolyzable group represented by X, and thus is a reactive siloxane compound.

Note that R ²¹ is an aryl group or an alkyl group, and the meaning and preferred examples of these groups are the same as those of R ¹¹ . Note that a plurality of R ²¹ and X may be the same or different. R ²¹ may be substituted with a reactive group selected from the group consisting of an epoxy group, a mercapto group, a (meth) acryloyl group, a (meth) acryloyloxy group and a vinyl group.

Compound (II) may have a structure represented by the following formula (2c) (hereinafter, may be referred to as “structure 2b”) in addition to the above structure. Incidentally, a preferred embodiment and significance of R ²¹ are as defined above, R ²¹ existing in plural numbers may be the same or different.

That is, the compound (II) can be composed of only the structure 2a, only the structures 2a and 2b, only the structures 2a and 2c, and the structures 2a, 2b and 2c. Examples of the compound (II) include those having the partial structures of the following formulas (31), (32) and (33).

  Compound (II) may have X (hydroxyl group or hydrolyzable group) at the terminal of the main chain as shown by the above formula, and may have a hydroxyl group or hydrolyzable group as a side chain of the main chain. It may be. Compound (II) may have two or more hydroxyl groups or hydrolyzable groups, and it is preferable that at least one hydroxyl group or hydrolyzable group exists as a side chain of the main chain.

  The content ratio of the hydroxyl group or the hydrolyzable group in the compound (II) may be, for example, 5% by mass or more, and preferably 10% by mass or more. The content of the hydroxyl group or the hydrolyzable group in the compound (II) may be, for example, 70% by mass or less, preferably 65% by mass or less, and more preferably 60% by mass or less.

  The weight average molecular weight (Mw) of compound (II) may be, for example, from 200 to 5,000. The Mw of the compound (II) is a value measured by GPC (gel permeation chromatography) and converted to standard polystyrene.

Compound (II) is represented by a composition formula, for example:
[R ²¹ SiO _3/2 ] _x [R ²¹ XSiO _2/2 ] _y [R ²¹ ₂ SiO _2/2 ] _z
[XSiO _3/2 ] _x [R ²¹ XSiO _2/2 ] _y [R ²¹ ₂ SiO _2/2 ] _z
[R ²¹ XSiO _2/2 ] _y [R ²¹ ₃ SiO] _{w
^{[R 21 SiO 3/2] x [}} R 21 XSiO 2/2] y [R 21 2 SiO 2/2] z [R 21 3 SiO] w
_{^{[XSiO 3/2] x [R 21}} XSiO 2/2] y [R 21 2 SiO 2/2] z [R 21 3 SiO] w
Can be expressed as In the formula, R ²¹ is an aryl group or an alkyl group, and the meaning and preferred examples of these groups are the same as those of R ¹¹ . X is a hydroxyl group or a hydrolyzable group, and x, y, z and w are numbers that add up to 1 in the same composition, and represent the molar ratio of each unit.

  The curable composition contains the compounds (I) and (II) described above. The compound (II) has a hydroxyl group or a hydrolyzable group bonded to a silicon atom, and the compound (I) may have a hydrogen atom, a hydroxyl group or a hydrolyzable group bonded to a silicon atom. Therefore, a curable composition containing both compounds reacts by hydrolysis and condensation reactions. When compound (I) has reactivity, compounds (I) and (II) are chemically bonded. Such a curable composition, when cured, has excellent adhesion to an adherend and has excellent heat resistance that can withstand severe temperature changes. Further, since the curable composition has the specific structure of the compounds (I) and (II), even if a filler such as a phosphor powder or a white pigment is blended, the cured product has sufficient adhesion and heat resistance. Is maintained. For this reason, the curable composition can be suitably used for an optical member. The optical member in the present embodiment includes a light-emitting element (light-emitting diode, semiconductor laser, or the like) or a member incorporated in a display device (organic EL, liquid crystal display, projector, or the like). For example, it can be suitably used for a binder for a light emitting layer in a light emitting element or a binder for a light reflecting layer adjacent to the light emitting layer.

  In addition, the curable composition can have a structure in which silsesquioxane structures are cross-linked because the compounds (I) can be bonded to each other. For this reason, the cured product of the curable composition has good gas barrier properties. Therefore, it can be suitably used for applications such as a protective layer of a phosphor layer in a light emitting element.

  In the curable composition, the ratio C1 / C2 of the content C1 of the compound (I) to the content C2 of the compound (II) may be, for example, 1/9 to 9/1 by mass ratio, and is preferably 3/7 to 8/2.

  The curable composition may contain a silsesquioxane having a hydroxyl group and / or a hydrolyzable group represented by the formula (24) in addition to the compound (I) and the compound (II). In this case, the compound is preferably used in an amount of 1 to 30 parts by mass based on 100 parts by mass of the compound (I). By containing such a compound, the hardness and flexibility of the cured product can be changed depending on the application.

  The curable composition may contain a solvent, a filler, a curing catalyst, and the like as components other than the compound (I) and the compound (II). Examples of the solvent include toluene, xylene, alcohols and the like. Examples of the filler include an inorganic or organic filler.

  As the curing catalyst, for example, an organometallic compound can be applied. Examples of the organic metal compound include organic tin compounds such as dibutyltin diacetate, dibutyltin dioctylate, and dibutyltin dilaurate; and organic compounds such as aluminum tris (acetylacetone), aluminum tris (acetoacetate ethyl), and aluminum diisopropoxy (acetoacetate ethyl). Aluminum compounds; organic zirconium compounds such as zirconium (acetylacetone), zirconium tris (acetylacetone), zirconium tetrakis (ethylene glycol monomethyl ether), zirconium tetrakis (ethylene glycol monoethyl ether), zirconium tetrakis (ethylene glycol monobutyl ether); titanium tetrakis ( Ethylene glycol monomethyl ether), titanium tetrakis (d Glycol monoethyl ether), organic titanium compounds such as titanium tetrakis (ethylene glycol monobutyl ether) and the like.

  Examples of the curing catalyst further include mineral acids such as hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid; organic acids such as formic acid, acetic acid, oxalic acid, and trifluoroacetic acid; inorganic bases such as ammonia, sodium hydroxide, and potassium hydroxide; And organic bases such as alkanolamines; amino-modified silicones, aminosilanes, silazanes, and amino compounds such as amines.

  The curable composition can be cured by, for example, heat treatment. The heating temperature during curing may be, for example, 100 ° C. or higher, and is preferably 200 ° C. or higher because the condensation reaction can proceed reliably in a short time.

  The curable composition may be in a liquid state. Such a curable composition can be easily mixed with the phosphor powder, and can be more suitably used as a binder for a light emitting layer in an optical member. Particularly, it is preferable that the compound (I) is liquid at 25 ° C. and 1 atm.

  The curable composition may have an appropriate viscosity in view of each process such as mixing with a filler, molding, and curing. The viscosity at 25 ° C. of the curable composition may be, for example, 30000 mPa · s or less, or 15000 mPa · s or less. The lower limit of the viscosity may be, for example, 100 mPa · s or more. The viscosity of the curable composition can be appropriately adjusted by, for example, diluting with the above-mentioned solvent. The viscosity of the curable composition at 25 ° C. can be measured using a B-type viscometer according to JIS K7117-1 (1999 version).

  Hereinafter, the content of the present invention will be described in more detail using examples and comparative examples, but the present invention is not limited to the following examples.

(Synthesis example 1)
1.75 g of phenylsilsesquioxane (trade name: SR-23, manufactured by Konishi Chemical Industry Co., Ltd., ethoxy-terminated homophenylsilsesquioxane, hereinafter sometimes referred to as “phenylSQ”), 0.78 g of phenyl Trimethoxysilane (trade name: KBM103, manufactured by Shin-Etsu Chemical Co., Ltd.), 0.36 g of triethoxysilane (trade name: T1040, manufactured by Tokyo Chemical Industry Co., Ltd.), 0.48 g of dimethylpolysiloxane having hydroxyl groups at both ends (trade name) Name: DMS-S12, manufactured by Gelest, molecular weight: 400 to 700 g / mol), and 0.45 g of dimethylethoxyphenylsilane (trade name: LS-3300, manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed with a solvent (1.5 g of (Propanol and 2.5 g of toluene). Next, while stirring this mixture, 0.61 g of a 1.2% aqueous hydrochloric acid solution was added dropwise. The resulting solution was stirred at 85 ° C. for 6 hours. After the reaction, the solvent and by-products were removed to obtain a silsesquioxane compound (hereinafter sometimes referred to as “SQ1”).

(Examples 1 to 6, Comparative Example 1)
SQ1, phenyl SQ, and a siloxane compound (trade name: X-40-9227, manufactured by Shin-Etsu Chemical Co., Ltd., a silicone oligomer having a structure represented by Formula (2a) or Formulas (2a) and (2b)) R ²¹ Have a methyl group and a phenyl group, and X is a methoxy group) in a mass ratio as shown in Table 1 below to obtain curable compositions of Examples 1 to 6 and Comparative Example 1.

[Transparency evaluation]
The curable compositions of Examples 1 to 6 and Comparative Example 1 were dropped on the surface of a sapphire glass substrate (surface roughness Ra: 20 nm) and applied using a Mayer bar (No. 3) to obtain a coating film. The obtained coating film was heated at 100 ° C. for 1 hour, then at 150 ° C. for 1 hour, then at 200 ° C. for 2 hours, and then at 250 ° C. for 5 hours to obtain a cured product for evaluation. Obtained. The transparency of the cured product was visually observed. The results are shown in Table 2 below.

(Examples 11 to 17)
According to the composition in Table 3 below, a curable composition was obtained in the same manner as in Example 1. In Table 3, the numbers represent the blending mass%, and the numbers in parentheses represent the mol%. Details of the components are as follows.
DMS-XM11: dimethylpolysiloxane having hydroxyl groups at both ends (manufactured by Gelest, molecular weight: 900 to 1000 g / mol)
YF3804: dimethyl-diphenylpolysiloxane (manufactured by Momentive, molecular weight: 6000 g / mol)
LS510: Trimethyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.)

In addition, the mass% of the silicon compounds (DMS-S12, DMS-XM11) represented by the formula (22) in all the raw materials used for the synthesis of the silsesquioxane compound is shown in Table 4 below. Note that the values in parentheses are mol%.

[Evaluation of siloxane skeleton]
About the curable composition of Examples 11-16, transparency was evaluated similarly to the said transparency evaluation. The results are shown in Table 5 below.

[Heat shock evaluation]
Regarding the cured product for evaluation obtained by the above-described method for evaluating transparency, a cycle of −40 ° C. for 30 minutes / 200 ° C. for 30 minutes was repeated 500 times, and peeling of the cured product and generation of cracks were evaluated. The results are shown in Table 6 below.
A: Neither peeling of the cured product nor cracking of the cured product are observed.
B: At least one of peeling of the cured product and cracking of the cured product is observed.

[Evaluation of Optical Properties 1]
To 100 parts by mass of the curable composition of Example 4 or 5, 5 parts by mass of a catalyst (trade name: X-40-2309A, manufactured by Shin-Etsu Chemical Co., Ltd., phosphoric acid 15%) was added, and further 30% by mass. Then, titania powder (trade name: CR-90, manufactured by Ishihara Sangyo Co., Ltd.) was added to the mixture, and the mixture was stirred so as to be uniform to obtain a curing solution. This curing solution was poured into a hole (hole diameter 15 mm, depth 0.6 mm) of a 1-hole hole slide glass, heated at 100 ° C. for 2 hours, further heated at 150 ° C. for 2 hours, 200 ° C. for 2 hours, 250 ° C. For 1 hour to obtain a cured product for evaluation. The cured product was irradiated with ultraviolet rays using a QUV weather tester (UVA-351 nm lamp, manufactured by Q-LAB). After one week of ultraviolet irradiation, the color tone parameters (a ^* , b ^* ) were measured and compared with the initial values. The results are shown in Table 7 below.

[Evaluation of Optical Properties 2]
To 100 parts by mass of the curable compositions of Examples 4 to 6, 5 parts by mass of a catalyst (trade name: X-40-2309A, manufactured by Shin-Etsu Chemical Co., Ltd., phosphoric acid 15%) was added, and further 30% by mass. Then, titania powder (trade name: CR-90, manufactured by Ishihara Sangyo Co., Ltd.) was added to the mixture, and the mixture was stirred so as to be uniform to obtain a curing solution. A curing solution was obtained in the same manner as above except that no titania powder was added. This curing solution was poured into a hole (hole diameter 15 mm, depth 0.6 mm) of a 1-hole hole slide glass, heated at 100 ° C. for 2 hours, further heated at 150 ° C. for 2 hours, 200 ° C. for 2 hours, 250 ° C. For 1 hour to obtain a cured product for evaluation. The cured product was irradiated with ultraviolet rays using a QUV weather tester (UVA-351 nm lamp, manufactured by Q-LAB). After 3000 hours of UV irradiation, color tone parameters (L ^* , a ^* , b ^* ) were measured and compared with the initial values. The results are shown in Table 8 below.

[Heat resistance evaluation]
To 100 parts by mass of the curable compositions of Examples 4 to 6, 5 parts by mass of a catalyst (trade name: X-40-2309A, manufactured by Shin-Etsu Chemical Co., Ltd., phosphoric acid 15%) was added, and further 30% by mass. Then, titania powder (trade name: CR-90, manufactured by Ishihara Sangyo Co., Ltd.) was added to the mixture, and the mixture was stirred so as to be uniform to obtain a curing solution. This curing solution was applied on an alumina substrate using a Mayer bar (No. 3), heated at 100 ° C. for 2 hours, and further heated at 150 ° C. for 2 hours, 200 ° C. for 2 hours, and 250 ° C. for 1 hour, and evaluated. To obtain a cured product. This cured product was held in an oven heated to 180 ° C. for 1000 hours, and peeling of the cured product and generation of cracks were evaluated. The results are shown in Table 9 below.
A: Neither peeling of the cured product nor cracking of the cured product are observed.
B: At least one of peeling of the cured product and cracking of the cured product is observed.

According to the curable composition of the above-described embodiment, a remarkable property which cannot be obtained by a conventional composition is exhibited. That is, even when the cured product is exposed to a high temperature for a long period of time or is irradiated with ultraviolet rays for a long period of time, there is very little change in optical characteristics. Here, the optical characteristics refer to practical characteristics when a cured product of the curable composition is applied to an optical member, and include transparency, a color tone parameter, and the like. The curable composition further has high adhesion of the cured product to various substrates, and is highly transparent even at the initial stage and after heat shock (for example, -40 ° C for 30 minutes / 200 ° C for 30 minutes of 500 cycles). The property is maintained, and cracks hardly occur. Therefore, the present invention can be applied not only to optical members but also to various uses.

Claims (13)

A silsesquioxane compound having a structure represented by the following formulas (1a) and (1b):

A curable composition containing the following formula (2a) or a siloxane compound having a structure represented by the following formulas (2a) and (2b).

[In the formula, R ¹¹ is an aryl group, an alkyl group or a hydrogen atom, R ¹² is a hydrogen atom, an aryl group or an alkyl group, R ²¹ is an aryl group or an alkyl group, X is a hydroxyl group or a hydrolyzable group, and n is 2 to 2. 100 number, respectively. However, a plurality of R ¹¹ , R ¹² , R ²¹ and X may be the same or different, and at least one of R ¹¹ is an aryl group. ] The curable composition according to claim 1, wherein the silsesquioxane compound further has a structure represented by the following formula (1c).

[In the formula, R ¹³ represents an aryl group or an alkyl group. However, a plurality of R ¹³ may be the same or different. ]   The curable composition according to claim 1, wherein at least one of a hydroxyl group and a hydrolyzable group is bonded to at least one silicon atom of the silsesquioxane compound.   The curable composition according to any one of claims 1 to 3, further comprising a silsesquioxane having a hydroxyl group and / or a hydrolyzable group. The silsesquioxane compound,
A silane having three hydroxyl groups and / or hydrolyzable groups and one aryl group bonded to a silicon atom;
A silicone having two or more hydroxyl groups and / or hydrolyzable groups bonded to a silicon atom;
A hydrosilane having three of a hydroxyl group and / or a hydrolyzable group bonded to a silicon atom;
The curable composition according to any one of claims 1 to 4, which is a reaction product of a silicon compound containing:   The curable composition according to claim 5, wherein the silicon compound further contains a silsesquioxane having a hydroxyl group and / or a hydrolyzable group bonded to a silicon atom.   The curable composition according to claim 5, wherein the silicon compound further contains three alkyl groups and / or aryl groups, one hydroxyl group and / or one hydrolyzable group, and silane bonded to a silicon atom. Stuff.   The ratio of the structure represented by the formula (1b) to the entire structure represented by the formulas (1a) and (1b) is 2 to 12 mol%. The curable composition according to the above.   The ratio of the structure represented by the formula (1c) to the entire structure represented by the formulas (1a), (1b) and (1c) is 3 to 50 mol%. The curable composition according to claim 1.   The curable composition according to claim 1, wherein the silsesquioxane compound is liquid at 25 ° C. and 1 atm.   The curable composition according to any one of claims 1 to 10, wherein the viscosity at 25 ° C is 100 to 30,000 mPa · s.   A cured product of the curable composition according to claim 1. An optical member comprising the cured product according to claim 12.