JP2022151345A - Curable polysilsesquioxane compound and cured product - Google Patents

Abstract

To provide a curable polysilsesquioxane compound which has a high refractive index and is suitably used in the optical field and to provide a cured product obtained by curing the curable polysilsesquioxane compound.SOLUTION: There are provided: a curable polysilsesquioxane compound having a repeating unit [a repeating unit (1)] represented by the formula (a-1) [R1 represents an unsubstituted aryl group having 6 to 12 carbon atoms or an aryl group having a substituent and 6 to 12 carbon atoms] and a repeating unit [a repeating unit (2)] represented by the formula (a-2) [R2 represents an unsubstituted alkyl group having 5 to 12 carbon atoms or an alkyl group having a substituent and 5 to 12 carbon atoms]; and a cured product obtained by curing the curable polysilsesquioxane compound.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a curable polysilsesquioxane compound having a high refractive index and suitable for use in the optical field, and a cured product of this curable polysilsesquioxane compound.

Conventionally, curable compositions have been variously improved according to their uses, and have been widely used industrially as raw materials for optical parts and moldings, adhesives, coating agents, and the like.
Curable compositions are also attracting attention as compositions for optical element fixing materials such as adhesives for optical element fixing materials and sealing materials for optical element fixing materials.

Optical devices include various lasers such as semiconductor lasers (LD), light emitting devices such as light emitting diodes (LED), light receiving devices, composite optical devices, optical integrated circuits, and the like.
In recent years, blue-light and white-light optical elements with shorter peak emission wavelengths have been developed and widely used. The brightness of such light-emitting elements with a short peak wavelength of light emission has been rapidly increased, and along with this, the amount of heat generated by the optical elements tends to increase further.

However, with the recent increase in brightness of optical elements, the cured product of the optical element fixing composition is exposed to higher energy light and higher temperature heat generated from the optical element for a long time, resulting in a decrease in adhesive strength. A problem arose.

In order to solve this problem, Patent Documents 1 to 3 propose compositions for optical element fixing materials containing a curable polysilsesquioxane compound as a main component.

By the way, when an optical element or the like is fixed using a curable composition, a curable composition having an appropriate refractive index may be selected in accordance with the refractive index of surrounding members in order to increase the light extraction efficiency. be.
For example, in order to suppress reflection at the interface between the sealant and the fixing material and improve the light extraction efficiency, it is preferable that the difference between the refractive index of the sealant and the refractive index of the fixing material is small.
Therefore, when using a sealant with a relatively high refractive index, it becomes necessary to form the fixer using a curable composition with a similarly high refractive index.
Therefore, a curable polysilsesquioxane compound having a high refractive index has been desired as a main component of such a curable composition.

Patent Document 4 describes a polysilsesquioxane compound having both an aliphatic hydrocarbon group or derivative thereof and an aromatic hydrocarbon group or derivative thereof.
However, this polysilsesquioxane compound melts when heated and does not have thermosetting properties. Therefore, the polysilsesquioxane compound described in Patent Document 4 does not function as a curable component of the curable composition.
As a technique related to the invention described in Patent Document 4, Patent Document 5 discloses a method for producing a polysilsesquioxane liquid.

JP-A-2004-359933 JP 2005-263869 A JP 2006-328231 A JP 2020-76057 A JP 2013-253223 A

The present invention has been made in view of the actual situation of the prior art described above, and a curable polysilsesquioxane compound having a high refractive index and suitable for use in the optical field, and the curable polysilsesquioxane An object is to provide a cured product of a compound.

In order to solve the above problems, the present inventors have extensively studied curable polysilsesquioxane compounds.
as a result,
(i) curable polysilsesquioxane compounds containing many aryl groups tend to have a high refractive index;
(ii) Cracks may occur in the cured product of the curable polysilsesquioxane compound containing many aryl groups, and (iii) the curable polysilsesquioxane compound containing many aryl groups By introducing a chain alkyl group, it is possible to suppress the occurrence of cracks when it is cured,
and completed the present invention.

Thus, according to the present invention, the following curable polysilsesquioxane compounds [1] to [5] and a cured product of [6] are provided.

[1] (a-1) below

[R ¹ represents an unsubstituted aryl group having 6 to 12 carbon atoms or a substituted aryl group having 6 to 12 carbon atoms. ]
A repeating unit represented by [repeating unit (1)], and the following formula (a-2)

[R ² represents an unsubstituted alkyl group having 5 to 12 carbon atoms or a substituted alkyl group having 5 to 12 carbon atoms. ]
A curable polysilsesquioxane compound having a repeating unit represented by [repeating unit (2)].
[2] The curable polysilsesquit of [1], wherein the amount of the repeating unit (1) is 50 mol% or more and less than 95 mol% with respect to the total amount of the repeating unit (1) and the repeating unit (2). Oxane compound.
[3] The curable polysilsesquioxane compound according to [1] or [2], wherein the total amount of repeating units (1) and repeating units (2) is 90 to 100 mol% of all repeating units.
[4] The curable polysilsesquioxane compound according to any one of [1] to [3], which has a weight average molecular weight (Mw) of 500 to 5,000.
[5] The curable polysilsesquioxane compound according to any one of [1] to [4], which has a refractive index (nD) at 25°C of 1.50 to 1.56.
[6] A cured product obtained by curing the curable polysilsesquioxane compound according to any one of [1] to [5].

INDUSTRIAL APPLICABILITY According to the present invention, a curable polysilsesquioxane compound having a high refractive index and suitable for use in the optical field, and a cured product of this curable polysilsesquioxane compound are provided.

1 is a ¹ H-NMR spectrum diagram of the polysilsesquioxane compound obtained in Example 1. FIG. 1 is a ¹ H-NMR spectrum diagram of the polysilsesquioxane compound obtained in Example 2. FIG. 1 is a ¹ H-NMR spectrum of the polysilsesquioxane compound obtained in Example 3. FIG.

Hereinafter, the present invention will be described in detail by dividing into 1) a curable polysilsesquioxane compound and 2) a cured product.

1) Curable polysilsesquioxane compound The curable polysilsesquioxane compound of the present invention is the following (a-1)

〔Ｒ^１は、無置換の炭素数６～１２のアリール基、又は、置換基を有する炭素数６～１２のアリール基を表す。〕
で示される繰り返し単位〔繰り返し単位（１）〕、及び、下記式（ａ－２）

[R ¹ represents an unsubstituted aryl group having 6 to 12 carbon atoms or a substituted aryl group having 6 to 12 carbon atoms. ]
A repeating unit represented by [repeating unit (1)], and the following formula (a-2)

〔Ｒ^２は、無置換の炭素数５～１２のアルキル基、又は、置換基を有する炭素数５～１２のアルキル基を表す。〕
で示される繰り返し単位〔繰り返し単位（２）〕を有するものである。

[R ² represents an unsubstituted alkyl group having 5 to 12 carbon atoms or a substituted alkyl group having 5 to 12 carbon atoms. ]
It has a repeating unit [repeating unit (2)] represented by

In the present invention, whether or not it is a "curable polysilsesquioxane compound" is determined by the following tests.
(Method for determining curable polysilsesquioxane compound)
The polysilsesquioxane compound is divided into two, and 140 g of tetrahydrofuran is added to 0.8 g of one of the polysilsesquioxane compounds (solid content: 0.6% by mass) and left to stand for 24 hours. Next, the insoluble component in tetrahydrofuran is isolated and the amount of the insoluble component (M1) is weighed.
Next, after heating the other polysilsesquioxane compound at 140° C. for 24 hours, 140 g of tetrahydrofuran was added to 0.8 g of the polysilsesquioxane compound after heating (solid content: 0.6% by mass). is allowed to stand for 24 hours. Next, the insoluble component in tetrahydrofuran is isolated and the amount of the insoluble component (M2) is weighed.
As a result of this test, when the ratio of the insoluble component amount (M1) is less than 2% by mass of the whole and the ratio of the insoluble component amount (M2) is 2% by mass or more of the whole (that is, the insoluble component amount is 0.5%). 016 g or more), the polysilsesquioxane compound before heating is referred to as a "curable polysilsesquioxane compound".

The curable polysilsesquioxane compound of the present invention has the repeating unit (1).
Since the repeating unit ( ¹ ) contains R1, the curable polysilsesquioxane compound of the present invention has a high refractive index.

The number of carbon atoms in the “unsubstituted aryl group having 6 to 12 carbon atoms” for R ¹ is preferably 6.
Examples of the “unsubstituted aryl group having 6 to 12 carbon atoms” for R ¹ include a phenyl group, a 1-naphthyl group, a 2-naphthyl group and the like.

The number of carbon atoms in the “aryl group having 6 to 12 carbon atoms and having a substituent” for R ¹ is preferably 6. The number of carbon atoms means the number of carbon atoms in the portion (aryl group portion) excluding the substituents. Therefore, when R ¹ is a “substituted aryl group having 6 to 12 carbon atoms”, the number of carbon atoms in R ¹ may exceed 12 in some cases.
Examples of the aryl group of the “substituted aryl group having 6 to 12 carbon atoms” for R ¹ include the same aryl groups as the “unsubstituted aryl group having 6 to 12 carbon atoms”.

The number of substituent atoms (excluding the number of hydrogen atoms) of the “aryl group having 6 to 12 carbon atoms having a substituent” for R ¹ is generally 1-30, preferably 1-20.
Examples of substituents of the "aryl group having 6 to 12 carbon atoms having a substituent" for R ¹ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, Alkyl groups such as t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group and isooctyl group; halogen atoms such as chlorine atom and bromine atom; alkoxy groups such as methoxy group and ethoxy group group; and the like.

Among these, R ¹ is preferably an unsubstituted aryl group having 6 to 12 carbon atoms, more preferably a phenyl group, because a curable polysilsesquioxane compound having a high refractive index can be efficiently obtained.

The curable polysilsesquioxane compound of the present invention may have one type of R ¹ or two or more types of R ¹ .

The curable polysilsesquioxane compound of the present invention further has the repeating unit (2).
Since the repeating unit (2) contains R ² , the curable polysilsesquioxane compound of the present invention is less likely to crack when cured.

The number of carbon atoms in the “unsubstituted alkyl group having 5 to 12 carbon atoms” for R ² is preferably 5 to 10, more preferably 5 to 8.
A curable polysilsesquioxane compound having an alkyl group with too many carbon atoms tends to be difficult to synthesize.
Examples of the “unsubstituted alkyl group having 5 to 12 carbon atoms” for R ² include n-pentyl group, n-hexyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n -dodecyl group and the like.

The number of carbon atoms in the “substituted alkyl group having 5 to 12 carbon atoms” for R ² is preferably 5 to 10, more preferably 5 to 8. The number of carbon atoms means the number of carbon atoms in the portion (alkyl group portion) excluding the substituents. Therefore, when R ² is a “substituted alkyl group having 5 to 12 carbon atoms”, the number of carbon atoms of R ² may exceed 12 in some cases.
Examples of the alkyl group of the “substituted alkyl group having 5 to 12 carbon atoms” for R ² include the same groups as the “unsubstituted alkyl group having 5 to 12 carbon atoms”.

The number of substituent atoms in the "substituted alkyl group having 5 to 12 carbon atoms" (excluding the number of hydrogen atoms) is generally 1-30, preferably 1-20.
Examples of substituents of the "substituted alkyl group having 5 to 12 carbon atoms" include halogen atoms such as chlorine and bromine atoms; cyano groups; and the like.

Among these, R ² is preferably an unsubstituted alkyl group having 5 to 12 carbon atoms, more preferably an unsubstituted alkyl group having 5 to 10 carbon atoms, and an unsubstituted alkyl group having 5 to 8 carbon atoms. More preferred.
When R ² is an unsubstituted alkyl group having 5 to 12 carbon atoms, the molecular weight of the curable polysilsesquioxane compound can be efficiently controlled.

The curable polysilsesquioxane compound of the present invention may have one type of ^R2 or ^two or more types of R2.

The curable polysilsesquioxane compound of the present invention may be a random copolymer, a block copolymer, a graft copolymer, an alternating copolymer, or the like. , random copolymers are preferred.
Further, the structure of the curable polysilsesquioxane compound of the present invention is any one of a ladder structure, a double decker structure, a cage structure, a partially cleaved cage structure, a cyclic structure and a random structure. good too.

The repeating unit (1) and repeating unit (2) are represented by the following formula (a-3).

[G represents a group represented by R ¹ or R ² . R ¹ and R ² each have the same meaning as above. O _1/2 means that an oxygen atom is shared with the adjacent repeating unit. ]

As shown by formula (a-3), the curable polysilsesquioxane compound of the present invention has three oxygen atoms bonded to a silicon atom, which are generally collectively referred to as T sites, and other groups (G It has a partial structure in which one group represented by is bonded.

In the curable polysilsesquioxane compound of the present invention, the amount of the repeating unit (1) is preferably 50 mol% or more and less than 95 mol% with respect to the total amount of the repeating unit (1) and the repeating unit (2). , more preferably 60 to 93 mol %, still more preferably 65 to 91 mol %, and particularly preferably 70 to 85 mol %.
When the amount of the repeating unit (1) is within the above range, it becomes easy to obtain a curable polysilsesquioxane compound having both a high refractive index and excellent crack suppression after curing.

The total amount of repeating units (1) and repeating units (2) in the curable polysilsesquioxane compound of the present invention is preferably 90 to 100 mol% of all repeating units in the curable polysilsesquioxane compound, More preferably 95 to 100 mol %, still more preferably 98 to 100 mol %.
When the total amount of the repeating unit (1) and the repeating unit (2) is within the above range, the curable polysilsesquioxane compound has good properties of both a high refractive index and suppression of crack generation after curing. becomes easier to obtain.

The weight average molecular weight (Mw) of the curable polysilsesquioxane compound of the present invention is preferably 500-5,000, more preferably 800-4,000.
Although the molecular weight distribution (Mw/Mn) of the curable polysilsesquioxane compound of the present invention is not particularly limited, it is usually 1.00 to 10.00, preferably 1.10 to 6.00, more preferably 1 .15 to 4.00.
A curable polysilsesquioxane compound having a weight-average molecular weight and a molecular weight distribution (Mw/Mn) within the above ranges is relatively easy to synthesize, and is suitable as a raw material for producing a cured product.
The mass average molecular weight (Mw) and number average molecular weight (Mn) can be obtained as standard polystyrene conversion values by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent, for example.

The refractive index (nD) at 25° C. of the curable polysilsesquioxane compound of the invention is preferably 1.50 to 1.56, more preferably 1.50 to 1.55.
When the refractive index (nD) at 25° C. of the curable polysilsesquioxane compound of the present invention is within the range of 1.50 to 1.56, a cured product having a high refractive index can be easily obtained.
The refractive index (nD) of the curable polysilsesquioxane compound can be measured using an Abbe refractometer.

The method for synthesizing the curable polysilsesquioxane compound of the present invention is not particularly limited. For example, by polycondensing at least one silane compound (1) represented by the following formula (a-4) and at least one silane compound (2) represented by the following formula (a-5), the present Curable polysilsesquioxane compounds of the invention can be synthesized.

(In the formula, R ¹ has the same meaning as above. R ³ represents an alkyl group having 1 to 10 carbon atoms, X ¹ represents a halogen atom, and p represents an integer of 0 to 3. Multiple R ³ , and a plurality of X ¹ may be the same or different.)

(In the formula, R ² has the same meaning as above. R ⁴ represents an alkyl group having 1 to 10 carbon atoms, X ² represents a halogen atom, and q represents an integer of 0 to 3. Multiple R ⁴ , and a plurality of X ² may be the same or different.)

The "alkyl group having 1 to 10 carbon atoms" for R ³ and R ⁴ includes methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group and t-butyl group. etc.
A chlorine atom, a bromine atom, etc. are mentioned as a halogen atom of X< ¹ >, X< ² >.

Specific examples of the silane compound (1) include:
unsubstituted aryltrialkoxysilane compounds such as phenyltrimethoxysilane and phenyltriethoxysilane;
unsubstituted arylhalogenoalkoxysilane compounds such as phenylchlorodimethoxysilane, phenylchlorodiethoxysilane, phenyldichloromethoxysilane, phenyldichloroethoxysilane;
unsubstituted aryltrihalogenosilane compounds such as phenyltrichlorosilane;
Substituents such as 4-methylphenyltrimethoxysilane, 4-methoxyphenyltrimethoxysilane, 4-chlorophenyltrimethoxysilane, 4-methylphenyltriethoxysilane, 4-methoxyphenyltriethoxysilane, 4-chlorophenyltriethoxysilane, etc. aryltrialkoxysilane compounds having;
Substituents such as 4-methylphenylchlorodimethoxysilane, 4-methoxyphenylchlorodimethoxysilane, 4-chlorophenylchlorodimethoxysilane, 4-methylphenyldichloromethoxysilane, 4-methoxyphenyldichloromethoxysilane, 4-chlorophenyldichloromethoxysilane, etc. arylhalogenoalkoxysilane compounds having;
aryltrihalogenosilane compounds having a substituent such as 4-methylphenyltrichlorosilane, 4-methoxyphenyltrichlorosilane, 4-chlorophenyltrichlorosilane; and the like.
These silane compounds (1) can be used singly or in combination of two or more.

Specific examples of the silane compound (2) include:
unsubstituted alkyltrialkoxysilane compounds such as n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-dodecyltrimethoxysilane, n-dodecyltriethoxysilane, n-dodecyltripropoxysilane;
n-hexylchlorodimethoxysilane, n-hexylchlorodiethoxysilane, n-hexyldichloromethoxysilane, n-hexylbromodimethoxysilane, n-dodecylchlorodimethoxysilane, n-dodecylchlorodiethoxysilane, n-dodecyldichloromethoxysilane , n-dodecylbromodimethoxysilane and other unsubstituted alkylhalogenoalkoxysilane compounds;
unsubstituted alkyltrihalogenosilane compounds such as n-hexyltrichlorosilane, n-hexyltribromosilane, n-dodecyltrichlorosilane, n-dodecyltribromosilane;
alkyltrialkoxysilane compounds having a substituent such as 6-cyanohexyltrimethoxysilane, 6-chlorohexyltrimethoxysilane, 6-cyanohexyltriethoxysilane, 6-chlorohexyltriethoxysilane;
6-cyanohexylchlorodimethoxysilane, 6-chlorohexylchlorodimethoxysilane, 6-cyanohexylchlorodiethoxysilane, 6-chlorohexylchlorodiethoxysilane, 6-cyanohexyldichloromethoxysilane, 6-chlorohexyldichloromethoxysilane, Alkylhalogenoalkoxysilane compounds having substituents such as 6-cyanohexyldichloroethoxysilane and 6-chlorohexyldichloroethoxysilane;
alkyltrihalogenosilane compounds having a substituent such as 6-cyanohexyltrichlorosilane, 6-chlorohexyltrichlorosilane; and the like.
These silane compounds (2) can be used singly or in combination of two or more.

The method of polycondensing the silane compound is not particularly limited. For example, a method of adding a predetermined amount of a polycondensation catalyst to a silane compound in a solvent or without a solvent and stirring the mixture at a predetermined temperature can be used. More specifically, (a) a method of adding a predetermined amount of an acid catalyst to a silane compound and stirring at a predetermined temperature, (b) adding a predetermined amount of a base catalyst to a silane compound and stirring at a predetermined temperature. (c) a method of adding a predetermined amount of an acid catalyst to a silane compound, stirring at a predetermined temperature, then adding an excess amount of a base catalyst to make the reaction system basic, and stirring at a predetermined temperature; mentioned.
Among these, the method (a) is preferable because the desired curable polysilsesquioxane compound can be obtained efficiently.

The polycondensation catalyst to be used may be either an acid catalyst or a base catalyst. Two or more polycondensation catalysts may be used in combination, but at least an acid catalyst is preferably used.
Acid catalysts include inorganic acids such as phosphoric acid, hydrochloric acid, boric acid, sulfuric acid and nitric acid; organic acids such as citric acid, acetic acid, methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid and p-toluenesulfonic acid; is mentioned. Among these, at least one selected from phosphoric acid, hydrochloric acid, boric acid, sulfuric acid, citric acid, acetic acid, and methanesulfonic acid is preferred.

Base catalysts include aqueous ammonia; trimethylamine, triethylamine, lithium diisopropylamide, lithium bis(trimethylsilyl)amide, pyridine, 1,8-diazabicyclo[5.4.0]-7-undecene, aniline, picoline, 1,4- organic bases such as diazabicyclo[2.2.2]octane and imidazole; organic hydroxides such as tetramethylammonium hydroxide and tetraethylammonium hydroxide; sodium methoxide, sodium ethoxide, sodium t-butoxide, potassium t-butoxide metal alkoxides such as; metal hydrides such as sodium hydride and calcium hydride; metal hydroxides such as sodium hydroxide, potassium hydroxide and calcium hydroxide; metal carbonates such as sodium carbonate, potassium carbonate and magnesium carbonate; metal hydrogen carbonates such as sodium hydrogen carbonate and potassium hydrogen carbonate;

The amount of the polycondensation catalyst used is generally in the range of 0.05 to 10 mol %, preferably 0.1 to 5 mol %, relative to the total mol amount of the silane compound.

When a solvent is used during polycondensation, the solvent to be used can be appropriately selected according to the type of the silane compound and the like. For example, water; aromatic hydrocarbons such as benzene, toluene and xylene; esters such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate and methyl propionate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone. alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, s-butyl alcohol and t-butyl alcohol; These solvents can be used singly or in combination of two or more.

The amount of the solvent used is 0.1 liter or more and 10 liters or less, preferably 0.1 liter or more and 2 liters or less, per mol of the total molar amount of the silane compound.

The temperature at which the silane compound is polycondensed is usually in the temperature range from 0°C to the boiling point of the solvent used, preferably in the range of 20°C or higher and 100°C or lower. If the reaction temperature is too low, the polycondensation reaction may proceed insufficiently. On the other hand, if the reaction temperature is too high, it becomes difficult to suppress gelation. The reaction is usually completed in 30 minutes to 30 hours.

As described in Patent Document 4, even if an aliphatic hydrocarbon group-containing silane compound and an aromatic hydrocarbon group-containing silane compound are used as raw material compounds, the desired curable polysilsesquioxane compound can be obtained. In some cases, a polysilsesquioxane compound that cannot be obtained and does not have curability is produced.
As will be described later, it is expected that the curability of the polysilsesquioxane compound is affected by whether the reaction system used to synthesize the polysilsesquioxane compound is an open system or a closed system. .

The curable polysilsesquioxane compound of the present invention has a high refractive index and is less likely to crack even when cured.
Therefore, the curable polysilsesquioxane compound of the present invention is suitably used as a raw material for producing optical members, a curable component for adhesives, and the like.

2) Cured Product The cured product of the present invention is obtained by curing the curable polysilsesquioxane compound of the present invention.
A method for curing the curable polysilsesquioxane compound of the present invention includes heat curing. The heating temperature for curing is usually 100 to 200° C., and the heating time is usually 10 minutes to 20 hours, preferably 30 minutes to 10 hours.

The cured product of the present invention is obtained by curing a curable polysilsesquioxane compound having a high refractive index. Therefore, the cured product of the present invention has a high refractive index.
The refractive index (nD) at 25° C. of the cured product of the present invention is preferably 1.50 to 1.56, more preferably 1.50 to 1.55.
The refractive index (nD) of the cured product can be measured using an Abbe refractometer.

The cured product of the present invention has a low elastic modulus and is suppressed from cracking.
The elastic modulus of the cured product of the present invention at 25° C. is preferably 0.3 to 1.8 GPa, more preferably 0.5 to 1.7 GPa, and even more preferably 0.7 to 1.5 GPa.
The elastic modulus of the cured product can be measured using a microsurface hardness tester.

The cured product of the present invention has a high refractive index and is resistant to cracks.
Therefore, the curable polysilsesquioxane compound of the present invention is suitably used as an optical member or a bonding member for optical members.

EXAMPLES The present invention will be described in more detail below with reference to examples. However, the present invention is by no means limited to the following examples.

(Example 1)
After charging 10.2 g (51.4 mmol) of phenyltrimethoxysilane and 3.78 g (13 mmol) of dodecyltrimethoxysilane into a 300 ml eggplant-shaped flask, 35% by mass was added to 3.48 g of distilled water while stirring. An aqueous solution of 0.0168 g of hydrochloric acid (0.25 mol % of HCl with respect to the total amount of phenyltrimethoxysilane and dodecyltrimethoxysilane) was added, and the whole volume was heated to 30°C for 2 hours and then to 80°C. The mixture was stirred for 18 hours.
After the reaction solution was allowed to cool to room temperature (25° C., the same below), 50 g of propyl acetate and 100 g of water were added to separate the layers, and the organic phase containing the reaction product was separated. Drying treatment was performed by adding magnesium sulfate to this organic phase. After removing magnesium sulfate by filtration, the organic phase was concentrated with an evaporator, and the obtained concentrate was vacuum-dried to obtain a polysilsesquioxane compound.

(Example 2)
After charging 12.19 g (61.5 mmol) of phenyltrimethoxysilane and 1.98 g (6.8 mmol) of dodecyltrimethoxysilane into a 300 ml eggplant-shaped flask, 3.69 g of distilled water was added to 3.69 g of distilled water while stirring. An aqueous solution of 0.0178 g by mass of hydrochloric acid (0.25 mol % of HCl with respect to the total amount of phenyltrimethoxysilane and dodecyltrimethoxysilane) was added, and the total volume was heated to 30°C for 2 hours and then to 80°C. It was warmed and stirred for 18 hours.
After allowing the reaction solution to cool to room temperature, 50 g of propyl acetate and 100 g of water were added thereto for liquid separation treatment, and the organic phase containing the reaction product was separated. Drying treatment was performed by adding magnesium sulfate to this organic phase. After removing magnesium sulfate by filtration, the organic phase was concentrated with an evaporator, and the obtained concentrate was vacuum-dried to obtain a polysilsesquioxane compound.

(Example 3)
After charging 22.84 g (115.2 mmol) of phenyltrimethoxysilane and 5.94 g (28.8 mmol) of hexyltrimethoxysilane into a 300 ml eggplant-shaped flask, 7.78 g of distilled water was added to 7.78 g of distilled water while stirring. An aqueous solution of 0.0376 g by mass of hydrochloric acid (0.25 mol % of HCl with respect to the total amount of phenyltrimethoxysilane and hexyltrimethoxysilane) was added, and the total volume was heated to 30°C for 2 hours and then to 80°C. It was warmed and stirred for 18 hours.
After allowing the reaction solution to cool to room temperature, 50 g of propyl acetate and 100 g of water were added thereto for liquid separation treatment, and the organic phase containing the reaction product was separated. Drying treatment was performed by adding magnesium sulfate to this organic phase. After removing magnesium sulfate by filtration, the organic phase was concentrated with an evaporator, and the obtained concentrate was vacuum-dried to obtain a polysilsesquioxane compound.

(Comparative example 1)
After charging 12.31 g (62.1 mmol) of phenyltrimethoxysilane and 2.61 g (15.5 mmol) of propyltrimethoxysilane into a 300 ml eggplant-shaped flask, 4.19 g of distilled water was added to 4.19 g of distilled water while stirring. An aqueous solution of 0.0202 g by mass of hydrochloric acid (0.25 mol % of HCl with respect to the total amount of phenyltrimethoxysilane and propyltrimethoxysilane) was added, and the total volume was heated to 30°C for 2 hours and then to 80°C. It was warmed and stirred for 16 hours.
After allowing the reaction solution to cool to room temperature, 50 g of propyl acetate and 100 g of water were added thereto for liquid separation treatment, and the organic phase containing the reaction product was separated. Drying treatment was performed by adding magnesium sulfate to this organic phase. After removing magnesium sulfate by filtration, the organic phase was concentrated with an evaporator, and the obtained concentrate was vacuum-dried to obtain a polysilsesquioxane compound.

(Comparative example 2)
After charging 14.46 g (72.9 mmol) of phenyltrimethoxysilane into a 300 ml eggplant-shaped flask, 0.0188 g of 35% by mass hydrochloric acid (based on phenyltrimethoxysilane) was added to 3.94 g of distilled water while stirring. 0.25 mol % of HCl) was added, and the whole volume was stirred at 30° C. for 2 hours, then heated to 70° C. and stirred for 18 hours. 15 g of propyl acetate and 0.0109 g of 28% aqueous ammonia solution (0.25 mol % with respect to phenyltrimethoxysilane) were added thereto and stirred for 2 hours.
After allowing the reaction solution to cool to room temperature, 50 g of propyl acetate and 100 g of water were added thereto for liquid separation treatment, and the organic phase containing the reaction product was separated. Drying treatment was performed by adding magnesium sulfate to this organic phase. After removing magnesium sulfate by filtration, the organic phase was concentrated with an evaporator, and the obtained concentrate was vacuum-dried to obtain a polysilsesquioxane compound.

(Reference example 1)
A polysilsesquioxane compound (glass powder) was obtained in the same manner as in Example 10 of Patent Document 4.
In Reference Example 1, the synthesis reaction was performed in a closed system with reference to the example of Patent Document 5. On the other hand, in Examples 1 to 3 and Comparative Examples 1 and 2, synthesis reactions were carried out in an open system using a reflux apparatus.

(Reference example 2)
Using the glass powder obtained in Reference Example 1, a polysilsesquioxane compound (polysilsesquioxane glass) was obtained in the same manner as in Example 10 of Patent Document 4.

[Curability evaluation]
The following experiments were performed on the polysilsesquioxane compounds obtained in Examples 1 to 3, Comparative Examples 1 and 2, and Reference Examples 1 and 2.
Each polysilsesquioxane compound was divided into two, and 140 g of tetrahydrofuran was added to 0.8 g of one of the polysilsesquioxane compounds (solid content: 0.6% by mass), and this was allowed to stand for 24 hours. Next, the insoluble component in tetrahydrofuran was isolated and the amount of the insoluble component (M1) was weighed.
Next, after heating the other polysilsesquioxane compound at 140° C. for 24 hours, 140 g of tetrahydrofuran was added to 0.8 g of the polysilsesquioxane compound after heating (solid content: 0.6% by mass). was allowed to stand for 24 hours. Next, the insoluble component in tetrahydrofuran was isolated and the amount of the insoluble component (M2) was weighed.
The results are shown below.

From these experimental results, the polysilsesquioxane compounds obtained in Examples 1 to 3 and Comparative Examples 1 and 2 have the property of becoming a high molecular weight substance having a three-dimensional structure, but the polysilsesquioxane compounds obtained in Reference Examples 1 and 2 It is speculated that the polysilsesquioxane compounds described do not have this property.
Therefore, the polysilsesquioxane compounds obtained in Examples 1 to 3 and Comparative Examples 1 and 2 are curable polysilsesquioxane compounds.

The polysilsesquioxane compounds obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were subjected to the following measurements and tests.

[Average molecular weight measurement]
The mass average molecular weight (Mw) and number average molecular weight (Mn) of the polysilsesquioxane compound were measured using the following equipment and conditions.
Apparatus name: HLC-8220GPC, manufactured by Tosoh Corporation Column: TSKgelGMHXL, TSKgelGMHXL, and TSKgel2000HXL sequentially connected Solvent: Tetrahydrofuran Standard substance: Polystyrene Injection volume: 20 μl
Measurement temperature: 40°C
Flow rate: 0.6 ml/min Detector: Differential refractometer

[ ¹ H-NMR measurement]
¹ H-NMR measurement of the polysilsesquioxane compounds obtained in Examples 1 to 3 was performed using the following equipment and conditions. The obtained NMR spectrum diagrams are shown in FIGS.
Device name: AV-500 manufactured by Bruker Biospin
¹ H-NMR resonance frequency: 500 MHz
Probe: 5mmφ solution probe Measurement temperature: Room temperature (25°C)
Repeat time: 1s
Number of times of integration: 16 times < ¹ H-NMR sample preparation method>
Polysilsesquioxane concentration: 3%
Measurement solvent: acetone Internal standard: TMS

[Refractive index measurement]
Using a multi-wavelength Abbe refractometer (manufactured by Atago Co., Ltd., DR-M2), the refractive index (nD) of the polysilsesquioxane compound (liquid) was measured at 25°C. The results are shown in Table 2.

[Elastic modulus measurement]
A polysilsesquioxane compound was applied to a thickness of about 150 μm on a slide glass. The obtained coating film was cured by heating at 120° C. for 2 hours and then at 150° C. for 3 hours to obtain a test piece.
Using a microsurface hardness tester (DUH-211S, manufactured by Shimadzu Corporation), a load-unload test was performed on the prepared test piece under the following measurement conditions, and the elastic modulus was calculated. The results are shown in Table 2.
Temperature: 25°C
Test force: 10mN
Load speed: 0.142mN/s

[Crack resistance evaluation]
A polysilsesquioxane compound was applied to a thickness of about 150 μm on a slide glass. The obtained coating film was cured by heating at 120° C. for 2 hours and then at 150° C. for 3 hours, and the presence or absence of cracks was visually observed. This test was performed four times for each polysilsesquioxane compound.
Table 2 shows (number of cracks/4).

The above examples and comparative examples reveal the following.
Each of the polysilsesquioxane compounds obtained in Examples 1 to 3 and Comparative Examples 1 and 2 has a phenyl group and therefore has a high refractive index.
However, the cured products of the polysilsesquioxane compounds obtained in Comparative Examples 1 and 2 have a high elastic modulus and cracks easily occur.
On the other hand, since the polysilsesquioxane compounds obtained in Examples 1 to 3 have alkyl groups having 5 or more carbon atoms, the cured products thereof have a low elastic modulus and the occurrence of cracks is suppressed.

Claims (6)

(a-1) below

[R ¹ represents an unsubstituted aryl group having 6 to 12 carbon atoms or a substituted aryl group having 6 to 12 carbon atoms. ]
A repeating unit represented by [repeating unit (1)], and the following formula (a-2)

[R ² represents an unsubstituted alkyl group having 5 to 12 carbon atoms or a substituted alkyl group having 5 to 12 carbon atoms. ]
A curable polysilsesquioxane compound having a repeating unit represented by [repeating unit (2)]. The curable polysilsesquioxane compound according to claim 1, wherein the amount of the repeating unit (1) is 50 mol% or more and less than 95 mol% with respect to the total amount of the repeating unit (1) and the repeating unit (2). . 3. The curable polysilsesquioxane compound according to claim 1, wherein the total amount of repeating units (1) and repeating units (2) is 90 to 100 mol % of all repeating units. The curable polysilsesquioxane compound according to any one of claims 1 to 3, which has a weight average molecular weight (Mw) of 500 to 5,000. The curable polysilsesquioxane compound according to any one of claims 1 to 4, which has a refractive index (nD) at 25°C of 1.50 to 1.56. A cured product obtained by curing the curable polysilsesquioxane compound according to any one of claims 1 to 5.

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