WO2023100992A1 - Silsesquioxane derivative, curable composition, cured product, and base material - Google Patents

Abstract

A silsesquioxane derivative represented by formula (1). In formula (1), R1 is a hydrogen atom or a C1-6 alkyl group, R2 is a C1-10 alkylene group, a C3-10 cycloalkylene group, a C6-10 arylene group, or a C7-12 aralkylene group, R3 is a fluoro group or a C1-20 fluoroalkyl group, R6 is a C2-12 organic group having at least one of an ethylenically unsaturated bond and a carbon-carbon triple bond, R7 is a C1-10 alkyl group, a C6-10 aryl group, or a C7-10 aralkyl group, and u, v, and y are positive numbers.

Description

Silsesquioxane derivative, curable composition, cured product and substrate

The present invention relates to silsesquioxane derivatives, curable compositions, cured products and substrates.

Silsesquioxane derivatives, which have both polymerizable groups and fluorine-based components in their molecules, are used as curable coating agents.

For example, Patent Document 1 discloses a coating agent having a film-forming component containing an organosilicon compound having a radically polymerizable functional group, a fluoroalkyl group and an alkoxysilyl group, and a photobase generator.

Patent Document 2 discloses a polyaliphatic aromatic silsesquioxane containing an ethylenically unsaturated group and a fluorine group, a reactive monomer containing one or more unsaturated groups in the molecule, an organic silane compound, and a photoinitiator. A photocurable organic-inorganic hybrid resin composition comprising

US Pat. No. 5,900,002 discloses high fluorine monomers containing M-type monomers with chlorosilane functional groups and fluoroalkane groups, T-type monomers with fluoroalkane groups, T-type monomers with (meth)acryloyl functional groups, and optionally Q-type monomers. A highly fluorinated silicone resin is disclosed, wherein the silicone resin is a highly fluorinated silicone resin having a fluorine content of at least 55 weight percent based on total weight.

[Patent Document 1] Japanese Unexamined Patent Publication No. 2020-33530 [Patent Document 2] Japanese Patent Publication No. 2014-529631 [Patent Document 3] Japanese Patent Publication No. 2019-520437

When using a silsesquioxane derivative, it is required that the cured product has good releasability, antifouling properties, etc., and excellent adhesion to the substrate.

Patent Document 1 discloses a silsesquioxane consisting only of T units obtained by polycondensation of 3-acryloxypropyltrimethoxysilane and 3,3,3-trifluoropropyltrimethoxysilane, a polymerizable ester. It describes that a coating agent containing a certain trimethylolpropane triacrylate, a photobase generator, and methanol as a solvent was applied to a silicon wafer, pre-baked, followed by ultraviolet irradiation and post-baking to prepare a coating film. However, in order to compensate for physical properties, such as scratch hardness and adhesion to substrates, which are degraded by substituting the polymerizable group of silsesquioxane with a fluoroalkyl group, polyfunctional acrylates, etc., which are polymerizable esters, are used. is compounded. Therefore, the contact angle of water is small, and the antifouling property is lowered.

Patent Document 2 describes that a photocurable organic-inorganic hybrid resin composition was produced as follows. First, a poly(ethylenically unsaturated group-containing fluorine group obtained by hydrolyzing and polycondensing trimethoxyphenylsilane, γ-methacryloxypropyltrimethoxysilane, methyltrimethoxysilane and perfluorooctyltriethoxysilane). An aliphatic-aromatic silsesquioxane is prepared. Then, the aforementioned polyaliphatic aromatic silsesquioxane, 2-(perfluorohexyl)ethyl acrylate, glycidyl methacrylate, (3-glycidoxypropyl)trimethoxysilane and photoinitiator were uniformly stirred at room temperature. After that, it is filtered to produce a photocurable organic-inorganic hybrid resin composition. Thus, in order to apply a silsesquioxane derivative containing an ethylenically unsaturated group consisting of only T units and a fluorine group in a solventless system, it is necessary to blend a reactive monomer, an organic silane compound, and the like. be. Also, in order to increase the chemical resistance of the composition and the cured density, it is necessary to add an organic silane compound to supplement the physical properties of the cured product. Furthermore, a curable composition containing a silsesquioxane derivative containing an ethylenically unsaturated group consisting of only T units and a fluorine group is applied to a substrate, and the applied curable composition is cured to obtain a cured product. When produced, there is also the problem that the adhesion of the cured product is not sufficient.

Patent Document 3 discloses (tridecafluoro-1,1,2,2-tetrahydrooctyl)dimethylchlorosilane as an M-type monomer and (tridecafluoro-1,1,2,2-tetrahydrooctyl)triethoxysilane as a T-type monomer. and 3-(trimethoxysilyl)propyl acrylate, and a highly fluorinated silicone resin consisting of M, T and Q units obtained by hydrolysis and polycondensation of tetraethylorthosilicate as the Q monomer. An optically transparent adhesive having a low refractive index is disclosed which contains this highly fluorinated silicone resin, a fluorinated (meth)acrylate monomer or perfluoropolyether, and a photoinitiator. In US Pat. No. 5,400,004, the optically clear adhesive needs to be made liquid by adding fluorinated (meth)acrylate monomers or perfluoropolyethers. Furthermore, when a curable composition containing a highly fluorinated silicone resin is applied to a substrate and the applied curable composition is cured to produce a cured product, there is also the problem that the adhesion of the cured product is insufficient. .

The present invention has been made in view of the above. An object of the present invention is to provide a flexible composition, a cured product obtained by curing the same, and a substrate comprising the cured product.

Means for solving the above problems include the following aspects.
<1> A silsesquioxane derivative represented by the following formula (1).

In formula (1), R ¹ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, R ² is an alkylene group having 1 to 10 carbon atoms, a cycloalkylene group having 3 to 10 carbon atoms, a carbon atom an arylene group having 6 to 10 carbon atoms or an aralkylene group having 7 to 12 carbon atoms, R ³ is a fluoro group or a fluoroalkyl group having 1 to 20 carbon atoms, and R ⁴ and R ⁵ are each independently hydrogen atom, saturated or unsaturated alkyl group having 1 to 20 carbon atoms, saturated or unsaturated cycloalkyl group having 3 to 8 carbon atoms, aryl group having 6 to 20 carbon atoms or 7 to 20 carbon atoms an aralkyl group, R ⁶ is an organic group having 2 to 12 carbon atoms having at least one of an ethylenically unsaturated bond and a carbon-carbon triple bond, and R ⁷ and R ⁸ each independently have 1 to 10 carbon atoms; an alkyl group, an aryl group having 6 to 10 carbon atoms or an aralkyl group having 7 to 10 carbon atoms, wherein a plurality of R ⁵ may be the same or different, and a plurality of R ⁷ may be the same. A plurality of R ⁸ may be the same or different, each of R ¹ to R ⁸ may be independently partially substituted with a substituent or a halogen atom, and u , v and y are positive numbers, and t, w, x and z are each independently 0 or positive numbers.
<2> The silsesquioxane derivative according to <1>, wherein t, w, x and z in the formula (1) are 0 and 0.01≤y/(u+v)≤1.
<3> The silsesquioxane derivative according to <1> or <2>, which has a viscosity of 10 mP·s to 7,000 mP·s at 25°C.

<4> A curable composition comprising the silsesquioxane derivative according to any one of <1> to <3> and a polymerization initiator.
<5> A cured product obtained by curing the curable composition according to <4>.
<6> The cured product according to <5>, which has a contact angle with water of 100° or more at 25°C.
<7> The cured product according to <5> or <6>, which has a refractive index of less than 1.42 at 25°C.
<8> A substrate comprising the cured product according to any one of <5> to <7>.

According to the present invention, there are provided a silsesquioxane derivative capable of producing a cured product having a large contact angle with water and excellent adhesion to a substrate, a curable composition containing the silsesquioxane derivative, and a curable composition containing the silsesquioxane derivative. It is possible to provide a cured product and a substrate comprising this cured product.

DETAILED DESCRIPTION OF THE INVENTION Embodiments for carrying out the present invention will be described in detail below. However, the present invention is not limited to the following embodiments. In the following embodiments, the constituent elements (including element steps and the like) are not essential unless otherwise specified. The same applies to numerical values and their ranges, which do not limit the present invention.
In this specification, the numerical range indicated using "-" includes the numerical values before and after "-" as the minimum and maximum values, respectively.
In the numerical ranges described stepwise in this specification, the upper limit or lower limit described in one numerical range may be replaced with the upper limit or lower limit of the numerical range described in other steps. good. Moreover, in the numerical ranges described in this specification, the upper and lower limits of the numerical ranges may be replaced with the values shown in the examples.
Moreover, in the present specification, a combination of two or more preferred aspects is a more preferred aspect.

In the present specification, each of R ¹ to R ⁸ in formula (1) may be independently partially substituted with a substituent or a halogen atom. For example, R ¹ to R ⁸ each independently represent an alkyl group, an aryl group, an aralkyl group, a vinyl group, an epoxy group, an oxetanyl group, a hydroxyl group, an amino group, an alkylamino group, an arylamino group, an aralkylamino group, and an ammonium group. , a thiol group, an isocyanurate group, a ureido group, an isocyanate group, a carboxy group, an acid anhydride group, or a halogen atom.
R ¹ to R ⁸ in formula (1) may each independently be unsubstituted, for example, R ¹ to R ³ or R ⁶ to R ⁸ (preferably R ¹ to R ³ and R ⁶ to R ⁸ ) may be unsubstituted.

[Silsesquioxane derivative]
The silsesquioxane derivative of the present invention is represented by the following formula (1).

In formula (1), R ¹ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, R ² is an alkylene group having 1 to 10 carbon atoms, a cycloalkylene group having 3 to 10 carbon atoms, a carbon atom an arylene group having 6 to 10 carbon atoms or an aralkylene group having 7 to 12 carbon atoms, R ³ is a fluoro group or a fluoroalkyl group having 1 to 20 carbon atoms, and R ⁴ and R ⁵ are each independently hydrogen atom, saturated or unsaturated alkyl group having 1 to 20 carbon atoms, saturated or unsaturated cycloalkyl group having 3 to 8 carbon atoms, aryl group having 6 to 20 carbon atoms or 7 to 20 carbon atoms an aralkyl group, R ⁶ is an organic group having 2 to 12 carbon atoms having at least one of an ethylenically unsaturated bond and a carbon-carbon triple bond, and R ⁷ and R ⁸ each independently have 1 to 10 carbon atoms; an alkyl group, an aryl group having 6 to 10 carbon atoms or an aralkyl group having 7 to 10 carbon atoms, wherein a plurality of R ⁵ may be the same or different, and a plurality of R ⁷ may be the same. A plurality of R ⁸ may be the same or different, each of R ¹ to R ⁸ may be independently partially substituted with a substituent or a halogen atom, and u , v and y are positive numbers, and t, w, x and z are each independently 0 or positive numbers.

Each structural unit that the silsesquioxane derivative of the present invention may contain is referred to as structural units (a) to (g) as follows.

In the silsesquioxane derivative of the present invention, u, v and y are positive numbers in formula (1), and t, w, x and z are each independently 0 or a positive number. That is, the silsesquioxane derivative of the present invention includes structural units (b), (c) and (f) among the structural units (a) to (g) described above, and optionally It contains at least one of structural unit (a), structural unit (d), structural unit (e), and structural unit (g).

The silsesquioxane derivative of the present invention contains the structural unit (b), the structural unit (c), and the structural unit (f), so that a cured product having a large contact angle with water and excellent adhesion to a substrate can be obtained. It is possible to manufacture. The reason for this is not particularly limited, but is presumed as follows.
Since the silsesquioxane derivative of the present invention contains the structural unit (c), the contact angle of the cured product tends to increase, and the refractive index of the cured product tends to decrease. On the other hand, when a fluorine-based component is introduced into a silsesquioxane derivative, the adhesiveness of the cured product to the substrate tends to decrease.
Furthermore, the silsesquioxane derivative of the present invention contains the structural unit (f), so that the silsesquioxane derivative and the curable composition containing the same have good storage stability and excellent adhesion to the substrate. Cured products can be given.

When applying a curable composition containing a silsesquioxane derivative or the like to a substrate, it is common to mix the curable composition and a solvent from the viewpoint of improving the coating properties of the curable composition. . However, when the curable composition contains a solvent, it is necessary to remove the solvent before curing the coating film, and it is desirable to reduce the amount of solvent used from the viewpoint of reducing environmental load and energy consumption. Considering this, there is a need for curable compositions that are solvent-free (solvent-free systems) and have low viscosities.

The silsesquioxane derivative of the present invention contains the structural unit (b), the structural unit (c), and the structural unit (f), so that the adhesiveness of the cured product is improved, and the silsesquioxane derivative Low viscosity is possible. Therefore, the amount of solvent used can be reduced, and it is also possible to use in a solvent-free system.

t, u, v, w, x, y and z in formula (1) represent molar ratios of structural units (a) to (g). In formula (1), t, u, v, w, x, y, and z are the structural units (a) to (g) that may be included in the silsesquioxane derivative represented by formula (1). represents a typical molar ratio. The molar ratio can be obtained from NMR (nuclear magnetic resonance) analysis values of the silsesquioxane derivative of the present invention. Further, when the reaction rate of each raw material of the silsesquioxane derivative is known, or when the yield is 100%, it can be determined from the charged amount of the raw material.
For example, the molar ratio of each structural unit of the silsesquioxane derivative is calculated by performing ¹ H-NMR analysis on a sample dissolved in deuterated chloroform or the like and, if necessary, further performing ²⁹ Si-NMR analysis. You may
The structure of the original silsesquioxane derivative may be estimated from the ratio of the structural units obtained by decomposing the structural units with an alkali or the like.
If necessary, known techniques such as mass spectrometry and IR (infrared absorption spectroscopy) analysis may be combined to determine the molar ratio of each structural unit of the silsesquioxane derivative.

Each of the structural units (b) to (g) in formula (1) may be of only one type, or may be of two or more types. The order of arrangement in formula (1) indicates the composition of the structural units, and does not mean the order of arrangement of the silsesquioxane derivatives. Therefore, the condensed form of the structural units in the silsesquioxane derivative of the present invention does not necessarily have to follow the sequence of formula (1).
Details of the structural units (a) to (g) will be described below.

(Constituent unit (a))
Structural unit (a) is a Q unit having 4 O _1/2 atoms (2 oxygen atoms) per silicon atom. The Q unit means a unit having 4 O _1/2 atoms per silicon atom.

The proportion of the structural unit (a) in the silsesquioxane derivative of the present invention is not particularly limited. For example, the molar ratio (t/(t+u+v+w+x+y+z)) of the structural unit (a) to all structural units is 0.1 or less from the viewpoint of the viscosity of the silsesquioxane derivative and the hardness of the cured product. is preferred, 0.05 or less is more preferred, and 0 is even more preferred. Here, a molar ratio of 0 means that the corresponding structural unit is not included, and the same applies hereinafter.

(Constituent unit (b))
Structural unit (b) has 3 O _1/2 (1.5 oxygen atoms) per silicon atom, and through R ² , the hydrogen atoms in the acryloyloxy group are other than hydrogen atoms The acryloyloxy group substituted by R ¹ is the T unit attached to the silicon atom. The T unit means a unit having 3 O _1/2 atoms per 1 silicon atom.

In structural unit (b), R ¹ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. The alkyl group having 1 to 6 carbon atoms may be linear or branched.

Examples of alkyl groups having 1 to 6 carbon atoms include methyl group, ethyl group, propyl group, butyl group, pentyl group and hexyl group, preferably methyl group or ethyl group, more preferably methyl group.

In structural unit (b), R ² is an alkylene group having 1 to 10 carbon atoms, a cycloalkylene group having 3 to 10 carbon atoms, an arylene group having 6 to 10 carbon atoms, or an aralkylene group having 7 to 12 carbon atoms. is the base. R ² is preferably an alkylene group having 1 to 10 carbon atoms or a cycloalkylene group having 3 to 10 carbon atoms, more preferably an alkylene group having 1 to 10 carbon atoms.

The alkylene group having 1 to 10 carbon atoms is preferably an alkylene group having 1 to 6 carbon atoms, more preferably an alkylene group having 2 to 4 carbon atoms, and even more preferably a propylene group. . The alkylene group having 1 to 10 carbon atoms may be linear or branched.
The cycloalkylene group having 3 to 10 carbon atoms is preferably a cycloalkylene group having 3 to 6 carbon atoms, more preferably a cycloalkylene group having 4 to 6 carbon atoms. The cycloalkylene group having 3 to 10 carbon atoms may have a branch.

The ratio of the structural unit (b) in the silsesquioxane derivative of the present invention is not particularly limited. For example, the molar ratio (u/(t+u+v+w+x+y+z)) of the structural unit (b) to all structural units is, from the viewpoint of ultraviolet (hereinafter also referred to as UV) curability, 0.1 to 0.9. It is preferably 0.2 to 0.8, and even more preferably 0.25 to 0.6.

(Constituent unit (c))
Structural unit (c) is a T unit having 3 O _1/2 (1.5 oxygen atoms) per silicon atom and R ³ being bonded to the silicon atom.

In structural unit (c), R ³ is a fluoro group or a fluoroalkyl group having 1 to 20 carbon atoms.

The fluoroalkyl group having 1 to 20 carbon atoms is preferably a fluoroalkyl group having 3 to 10 carbon atoms, more preferably a fluoroalkyl group having 5 to 10 carbon atoms. The number of fluorine atoms in the fluoroalkyl group having 1 to 20 carbon atoms is not particularly limited, and may be, for example, 3 or more, 5 to 37, or 7 to 17. good too.

For example, a fluoroalkyl group having 1 to 20 carbon atoms has an ethylene group (—CH ₂ CH ₂ —) as a structure bonded to a silicon atom when the number of carbon atoms is 3 or more, and the ethylene group has carbon It may be a substituent to which a perfluoroalkyl group having 1 to 18 atoms is bonded. The perfluoroalkyl group having 1 to 18 carbon atoms may be a perfluoroalkyl group having 3 to 10 carbon atoms or a perfluoroalkyl group having 5 to 8 carbon atoms.

Examples of the fluoroalkyl group having 1 to 20 carbon atoms include 3,3,3-trifluoro-propyl group, 1H,1H,2H,2H-nonafluoro-n-hexyl group, 1H,1H,2H,2H- tridecafluoro-n-octyl group and 1H,1H,2H,2H-heptadecafluoro-n-decyl group.

The ratio of the structural unit (c) in the silsesquioxane derivative of the present invention is not particularly limited. For example, the molar ratio (v / (t + u + v + w + x + y + z)) of the structural unit (c) to all structural units is 0.1 to 0 from the viewpoint of storage stability and contact angle and / or refractive index when cured. It is preferably 0.9, more preferably 0.2 to 0.8, even more preferably 0.25 to 0.6.

The molar ratio of the structural unit (b) to the structural unit (c) (structural unit (b): structural unit (c)) is determined from the viewpoint of storage stability and contact angle and / or refractive index when cured. , 0.1:0.9 to 0.9:0.1, more preferably 0.2:0.8 to 0.8:0.2, and 0.3:0. More preferably, it is 7-0.7:0.3.

In the silsesquioxane derivative of the present invention, the molar ratio ((u + v ) / (u + v + w)) is preferably 0.3 to 1, more preferably 0.5 to 1, from the viewpoint of storage stability and contact angle and / or refractive index when cured. It is preferably from 0.7 to 1, more preferably from 0.7 to 1.

(Constituent unit (d))
Structural unit (d) is a T unit having 3 O _1/2 (1.5 oxygen atoms) per silicon atom and R ⁴ bonded to the silicon atom.

In structural unit (d), R ⁴ is a hydrogen atom, a saturated or unsaturated alkyl group having 1 to 20 carbon atoms, a saturated or unsaturated cycloalkyl group having 3 to 8 carbon atoms, or 6 to It is an aryl group of 20 or an aralkyl group of 7 to 20 carbon atoms. Each substituent in R ⁴ is a substituent that does not correspond to a fluoroalkyl group having 1 to 20 carbon atoms, even if part of its structure is substituted.

A saturated or unsaturated alkyl group having 1 to 20 carbon atoms may be linear or branched. The saturated or unsaturated alkyl group having 1 to 20 carbon atoms is preferably a saturated or unsaturated alkyl group having 1 to 10 carbon atoms, more preferably a saturated alkyl group having 1 to 10 carbon atoms. more preferred.

Examples of saturated alkyl groups having 1 to 10 carbon atoms include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group and decyl group. From the viewpoint of heat resistance and hardness of the cured product, a methyl group or an ethyl group is preferable, and a methyl group is more preferable.

Examples of unsaturated alkyl groups having 1 to 10 carbon atoms include vinyl groups, 2-propenyl groups, and ethynyl groups.

A saturated or unsaturated cycloalkyl group having 3 to 8 carbon atoms may have a branch. A saturated or unsaturated cycloalkyl group having 3 to 8 carbon atoms is preferably a saturated or unsaturated cycloalkyl group having 4 to 6 carbon atoms.

The aryl group having 6 to 20 carbon atoms is preferably an aryl group having 6 to 10 carbon atoms.

Examples of the aryl group having 6 to 20 carbon atoms include a phenyl group, a group in which one or more hydrogen atoms of the phenyl group are substituted with an alkyl group having 1 to 10 carbon atoms, and a naphthyl group. A phenyl group is preferred from the viewpoint of heat resistance and hardness of the cured product.

The aralkyl group having 7 to 20 carbon atoms is preferably an aralkyl group having 7 to 10 carbon atoms.

Examples of the aralkyl group having 7 to 20 carbon atoms include groups in which one hydrogen atom of an alkyl group having 1 to 10 carbon atoms is substituted with an aryl group such as a phenyl group. Examples thereof include benzyl group and phenethyl group, and benzyl group is preferable from the viewpoint of heat resistance and hardness of the cured product.

When part of the structure represented by R ⁴ is substituted with a substituent or a halogen atom, examples of R ⁴ include a 3-glycidoxypropyl group and a 2-(3,4-epoxycyclohexyl)ethyl group. , 3-(3-ethyloxetan-3-yl)methoxypropyl group, 3-hydroxypropyl group, 3-aminopropyl group, 3-dimethylaminopropyl group, 3-hydroxypropyl group, 3-aminopropyl hydrochloride , hydrochloride of 3-dimethylaminopropyl group, p-styryl group, N-2-(aminoethyl)-3-aminopropyl group, N-phenyl-3-aminopropyl group, N-(vinylbenzyl)-2- Hydrochloride of aminoethyl-3-aminopropyl group, 3-ureidopropyl group, 3-mercaptopropyl group, 3-isocyanatopropyl group, 3-carboxypropyl group and 3-chloropropyl group.

The ratio of the structural unit (d) in the silsesquioxane derivative of the present invention is not particularly limited. For example, the molar ratio (w / (t + u + v + w + x + y + z)) of the structural unit (d) to the total structural units is preferably 0.1 or less, and 0.05 or less, from the viewpoint of the hardness of the cured product. It is more preferably 0, and more preferably 0.

(Constituent unit (e))
Structural unit (e) is a D unit having two O _1/2 per silicon atom (one oxygen atom) and two R ⁵ bonds to the silicon atom. The D unit means a unit having two O _1/2 atoms per one silicon atom.

In structural unit (e), R ⁵ is a hydrogen atom, a saturated or unsaturated alkyl group having 1 to 20 carbon atoms, a saturated or unsaturated cycloalkyl group having 3 to 8 carbon atoms, or 6 to It is an aryl group of 20 or an aralkyl group of 7 to 20 carbon atoms. In the structural unit (d), multiple R ⁵ may be the same or different. Preferred embodiments of R ⁵ are the same as R ⁴ in structural unit (d).

The ratio of the structural unit (e) in the silsesquioxane derivative of the present invention is not particularly limited. For example, the molar ratio (x/(t + u + v + w + x + y + z)) of the structural unit (e) to the total structural units is preferably 0.1 or less, and 0.05 or less, from the viewpoint of the hardness of the cured product. It is more preferably 0, and more preferably 0.

(Constituent unit (f))
Structural unit (f) has one O _1/2 per silicon atom (0.5 oxygen atoms), one R ⁶ and two R ⁵ are bonded to the silicon atom M Units. The M unit means a unit having one O _1/2 per one silicon atom.

In structural unit (f), R ⁶ is an organic group having 2 to 12 carbon atoms and having at least one of an ethylenically unsaturated bond and a carbon-carbon triple bond.

Examples of the organic group having 2 to 12 carbon atoms and having an ethylenically unsaturated bond include a vinyl group, an orthostyryl group, a methstyryl group, a parastyryl group, an acryloyloxymethyl group, a methacryloyloxymethyl group, and a 2-acryloyloxyethyl group. , 2-methacryloyloxyethyl group, 3-acryloyloxypropyl group, 3-methacryloyloxypropyl group, 8-acryloyloxyoctyl group, 8-methacryloyloxyoctyl group, 1-propenyl group, 2-propenyl group, 1-methylethenyl group , 1-butenyl group, 3-butenyl group, 1-pentenyl group, 4-pentenyl group, 3-methyl-1-butenyl group, 1-phenylethenyl group, 2-phenylethenyl group, ethynyl group, 1-propynyl 2-propynyl, 1-butynyl, 3-butynyl, 1-pentynyl, 4-pentynyl, 3-methyl-1-butynyl and phenylbutynyl groups. A vinyl group, a 2-propenyl group, an orthostyryl group, a metastyryl group or a parastyryl group is preferred, and a vinyl group is more preferred, from the viewpoint of hardness when cured.

In structural unit (f), R ⁷ is an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms or an aralkyl group having 7 to 10 carbon atoms. In the structural unit (f), multiple R ⁷ may be the same or different.

Examples of alkyl groups having 1 to 10 carbon atoms include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group and decyl group. From the viewpoint of heat resistance and hardness of the cured product, a methyl group or an ethyl group is preferable, and a methyl group is more preferable.

Examples of the aryl group having 6 to 10 carbon atoms include a phenyl group, a group in which one or more hydrogen atoms of the phenyl group are substituted with an alkyl group having 1 to 4 carbon atoms, and a naphthyl group. A phenyl group is preferred from the viewpoint of heat resistance and hardness of the cured product.

Examples of the aralkyl group having 7 to 10 carbon atoms include groups in which one hydrogen atom of an alkyl group having 1 to 4 carbon atoms is substituted with an aryl group such as a phenyl group. Examples thereof include benzyl group and phenethyl group, and benzyl group is preferable from the viewpoint of heat resistance and hardness of the cured product.

The proportion of the structural unit (f) in the silsesquioxane derivative of the present invention is not particularly limited. For example, the molar ratio (y/(t+u+v+w+x+y+z)) of the structural unit (f) to all structural units is preferably 0.01 to 0.5 from the viewpoint of viscosity and adhesion when cured. , more preferably 0.02 to 0.4, even more preferably 0.03 to 0.35, and particularly preferably 0.1 to 0.35.

In the silsesquioxane derivative of the present invention, the total molar ratio ((u + v + y) / (t + u + v + w + x + y + z)) of the structural unit (b), the structural unit (c) and the structural unit (f) occupying all structural units is the cured product From the viewpoint of adhesion and refractive index, it is preferably from 0.5 to 1, more preferably from 0.6 to 1, and even more preferably from 0.7 to 1.

The molar ratio between the structural unit (b) and the structural unit (f) (structural unit (b): structural unit (f)) is from 10:1 to 10:1 from the viewpoint of UV curability and adhesion when cured. It is preferably 1:2, more preferably 5:1 to 1:2.

(Constituent unit (g))
Structural unit (g) is an M unit having one O _1/2 (0.5 oxygen atom) per silicon atom and three R ⁸ bonds to the silicon atom.

In structural unit (g), R ⁸ is an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms or an aralkyl group having 7 to 10 carbon atoms. In the structural unit (g), multiple R ⁸ may be the same or different. Preferred embodiments of R ⁸ are the same as R ⁷ in structural unit (f). Each substituent in R ⁸ is a substituent that does not correspond to an organic group having 2 to 12 carbon atoms and having an ethylenically unsaturated bond, even if the structure is partially substituted. .

The proportion of the structural unit (g) in the silsesquioxane derivative of the present invention is not particularly limited. For example, the molar ratio (z / (t + u + v + w + x + y + z)) of the structural unit (g) to all structural units is preferably 0.1 or less, and 0.05 or less, from the viewpoint of the hardness of the cured product. It is more preferably 0, and more preferably 0.

(Other structural units (h))
The silsesquioxane derivative of the present invention may further contain (R ⁹ O _1/2 ) as a structural unit not containing Si (hereinafter also referred to as structural unit (h)).
Here, R ⁹ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. The alkyl group having 1 to 6 carbon atoms may be either an aliphatic group or an alicyclic group, and may be linear or branched. Specific examples of alkyl groups having 1 to 6 carbon atoms include methyl, ethyl, propyl, butyl, pentyl and hexyl groups.

Structural unit (h) is an alkoxy group which is a hydrolyzable group contained in the silicon compound described later, or an alkoxy group formed by substituting the hydrolyzable group of the silicon compound with an alcohol contained in the reaction solvent. It may be a hydroxyl group that remains in the molecule without hydrolysis or polycondensation, or a hydroxyl group that remains in the molecule without polycondensation after hydrolysis.

In formula (1), t, w, x and z are preferably 0. In formula (1), 0.01 ≤ y/(u + v) ≤ 1 is preferred, 0.1 ≤ y/(u + v) ≤ 0.8 is more preferred, and 0.3 ≤ y/( It is more preferable that u+v)≦0.6.

(Weight average molecular weight of silsesquioxane derivative)
The weight average molecular weight (hereinafter also referred to as "Mw") of the silsesquioxane derivative of the present invention is not particularly limited, and may be, for example, 300 to 30,000, or 500 to 15,000. may be from 700 to 10,000, or from 1,000 to 5,000.
In addition, Mw in the present invention means a value obtained by converting the molecular weight measured by GPC (gel permeation chromatography) using polystyrene as a standard substance. As the measurement conditions for Mw, for example, the measurement conditions in [Examples] described later can be used.

(Viscosity of silsesquioxane derivative)
The silsesquioxane derivative of the present invention preferably has a viscosity at 25° C. (viscosity when no accelerated test is performed) of 10 mPa·s to 7,000 mPa·s, more preferably 100 mPa·s to 6,000 mPa·s. s, more preferably 200 mPa·s to 5,000 mPa·s.
In the present invention, the viscosity at 25° C. means a value measured using an E-type viscometer (cone and plate type viscometer; for example, Toki Sangyo Co., Ltd. TVE22H-type viscometer).

(Method for producing silsesquioxane derivative)
The silsesquioxane derivative of the present invention can be produced by known methods. A method for producing a silsesquioxane derivative is disclosed in detail as a method for producing polysiloxane in WO 2013/031798 pamphlet and the like.

The silsesquioxane derivative of the present invention can be produced, for example, by the following method.
The method for producing a silsesquioxane derivative of the present invention comprises a condensation step of hydrolyzing and polycondensing the silicon compound to give the structural unit of formula (1) by condensation in a suitable reaction solvent. In the condensation step, for example, a silicon compound having three siloxane bond forming groups forming the structural unit (b) (T unit) (hereinafter also referred to as “silicon compound 1”) and the structural unit (c) (T a silicon compound (hereinafter also referred to as "silicon compound 2") having three siloxane bond-forming groups forming a unit) and a silicon forming a structural unit (f) (M unit) having one siloxane bond-forming group A compound (hereinafter also referred to as “silicon compound 3”) is used at least. In addition, if necessary, other silicon compounds forming the structural unit (a), the structural unit (d), the structural unit (e) or the structural unit (g) (hereinafter referred to as "silicon compound 4", "silicon compound 5 (also referred to as "silicon compound 6" or "silicon compound 7").

In the condensation step, silicon compounds 1 to 3 and, if necessary, other silicon compounds may be hydrolyzed and polycondensed. Alternatively, a part of the silicon compounds 1 to 3 and, if necessary, other silicon compounds are hydrolyzed and polycondensed to obtain an intermediate silsesquioxane derivative, and then the obtained intermediate product may be further subjected to hydrolysis and polycondensation reactions with the rest of the silicon compounds 1 to 3 and the like.

When the intermediate product is obtained as described above, the silicon compound 1, the silicon compound 2 and, if necessary, other silicon compounds are hydrolyzed and polycondensed, and then the obtained intermediate product and the silicon compound 3 are combined. may be further subjected to hydrolysis and polycondensation reactions. As a result, it is possible to suitably synthesize a silsesquioxane derivative whose terminal portion is blocked with the structural unit (f) derived from the silicon compound 3, suppresses the increase in viscosity of the silsesquioxane derivative, and is stable in storage. good properties.

In the method for producing a silsesquioxane derivative of the present invention, a silicon compound is hydrolyzed and polycondensed in the presence of a reaction solvent, and then the reaction solvent, by-products, residual monomers, water, etc. in the reaction solution are removed. It is preferable to provide a distillation step for distilling off.

Examples of the silicon compound 1 include (3-acryloyloxypropyl)trimethoxysilane, (3-acryloyloxypropyl)triethoxysilane, (8-acryloyloxyoctyl)trimethoxysilane, (3-methacryloyloxypropyl)trimethoxysilane. silane, (3-methacryloyloxypropyl)triethoxysilane, (8-methacryloyloxyoctyl)trimethoxysilane, (3-acryloyloxypropyl)trichlorosilane, (3-methacryloyloxypropyl)trichlorosilane.

Examples of the silicon compound 2 include trimethoxy(3,3,3-trifluoropropyl)silane, trimethoxy-1H,1H,2H,2H-nonafluoro-n-hexylsilane, triethoxy-1H,1H,2H,2H-tri Decafluoro-n-octylsilane and trimethoxy-1H,1H,2H,2H-heptadecafluoro-n-decylsilane.

Examples of the silicon compound 3 include 1,3-divinyltetramethyldisiloxane, 1,3-bis(p-styryl)tetramethyldisiloxane, 1,3-bis(3 -acryloyloxypropyl)tetramethyldisiloxane, 1,3-bis(3-methacryloyloxypropyl)tetramethyldisiloxane, etc., methoxydimethylvinylsilane, ethoxydimethylvinylsilane, chlorodimethylvinylsilane, dimethylvinylsilanol, (3-acryloyl oxypropyl)dimethylmethoxysilane, (3-methacryloyloxypropyl)dimethylmethoxysilane, p-styryldimethylmethoxysilane, ethynyldimethylmethoxysilane and the like.

Examples of the silicon compound 4 include tetramethoxysilane, tetraethoxysilane, and the like.

Silicon compound 5 includes, for example, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, octyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, benzyltrimethoxysilane, cyclohexyltri methoxysilane, vinyltrimethoxysilane, allyltrimethoxysilane, p-styryltrimethoxysilane, ethynyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3 -aminopropyltrimethoxysilane, hydrochloride of N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane, 3-ureidopropyltrialkoxysilane, 3-isocyanatopropyltriethoxysilane, tris-(tri methoxysilylpropyl)isocyanurate, 3-mercaptopropyltrimethoxysilane, 3-ethyl-3-[{3-(trimethoxysilyl)propoxy}methyl]oxetane, 3-ethyl-3-[{3-(triethoxysilyl ) propoxy}methyl]oxetane.

Examples of the silicon compound 6 include dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldidiethoxysilane, propylmethyldimethoxysilane, octylmethyldimethoxysilane, phenylmethyldimethoxysilane, diphenyldiethoxysilane, benzylmethyldimethoxysilane, cyclohexylmethyldimethoxysilane, vinylmethyldimethoxysilane, allylmethyldimethoxysilane, p-styrylmethyldimethoxysilane, ethynylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, N-2 -(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropylmethyldimethoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyl hydrochloride of methyldimethoxysilane, 3-ureidopropylmethyldialkoxysilane, 3-isocyanatopropylmethyldiethoxysilane, (3-acryloxypropyl)methyldimethoxysilane, (3-methacryloxypropyl)methyldiethoxysilane and the like. be done.

Examples of the silicon compound 7 include hexamethyldisiloxane, trimethylmethoxysilane, trimethylethoxysilane, trimethylchlorosilane, dimethylphenylmethoxysilane, and the like.

Alcohol may be used as a reaction solvent in the condensation step. Alcohol is a narrowly defined alcohol represented by the general formula R--OH, and is a compound having no functional group other than an alcoholic hydroxyl group.
Alcohol is not particularly limited, and examples include methanol, ethanol, 1-propanol, 2-propanol, 2-butanol, 2-pentanol, 3-pentanol, 2-methyl-2-butanol, 3-methyl-2- butanol, cyclopentanol, 2-hexanol, 3-hexanol, 2-methyl-2-pentanol, 3-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-3-pentanol, 2-ethyl-2-butanol, 2,3-dimethyl-2-butanol, cyclohexanol and the like. Among these, 2-propanol, 2-butanol, 2-pentanol, 3-pentanol, 3-methyl-2-butanol, cyclopentanol, 2-hexanol, 3-hexanol, 3-methyl-2-pentanol and secondary alcohols such as cyclohexanol are preferred.
In the condensation step, these alcohols may be used singly or in combination of two or more.

The reaction solvent used in the condensation step may be alcohol alone, or may be a mixed solvent with at least one sub-solvent. The co-solvent may be either a polar solvent, a non-polar solvent, or a combination of both.

Hydrolysis and polycondensation reactions in the condensation step proceed in the presence of water.
The amount of water used to hydrolyze the hydrolyzable group contained in the silicon compound is preferably 0.5 to 5 times the amount (mol) of the substance of the hydrolyzable group, more preferably 1 to 2 times the molar amount.
Moreover, the hydrolysis and polycondensation reaction of the silicon compound may be carried out without a catalyst or with a catalyst. When using a catalyst, inorganic acids such as sulfuric acid, nitric acid, hydrochloric acid and phosphoric acid; acid catalysts exemplified by organic acids such as formic acid, acetic acid, oxalic acid and p-toluenesulfonic acid, ammonia, tetramethylammonium hydroxide, water Base catalysts such as sodium oxide, potassium hydroxide, sodium carbonate and potassium carbonate are preferably used, and acid catalysts are more preferably used.
The amount of the catalyst used is preferably an amount corresponding to 0.01 mol% to 20 mol%, and preferably 0.1 mol% to 10 mol, relative to the total amount (mol) of silicon atoms contained in the silicon compound. % is more preferable.

The completion of hydrolysis and polycondensation reaction in the condensation step can be detected as appropriate by methods described in various publications. In addition, in the condensation step for producing the silsesquioxane derivative of the present invention, an auxiliary agent can be added to the reaction system.

By providing the aforementioned distillation step after the condensation step in the production of the silsesquioxane derivative of the present invention, the stability of the produced silsesquioxane derivative of the present invention can be improved. Distillation can be carried out under normal pressure or reduced pressure, can be carried out at room temperature or under heating, and can also be carried out under cooling.

The method for producing a silsesquioxane derivative can include a neutralization step for neutralizing the catalyst before the distillation step. A step of removing salts generated by neutralization by washing with water or the like can also be provided.

In addition, the silsesquioxane derivative represented by formula (1) is a group obtained by adding an acid or the like to an oxetanyl group or an epoxy group to open the ring, among the side chain functional groups derived from the silicon compound used in the production as a raw material. or may contain a hydroxyalkyl group formed by decomposition of an organic group having a (meth)acryloyl group, or a group obtained by adding an acid or the like to an unsaturated hydrocarbon group or the like. You can Specific examples thereof include those in which a part of formula (1) includes a structure represented by formula (A) and/or a structure represented by formula (B) below. As the content ratio, the original organic group having an oxetanyl group or an epoxy group, the original organic group having a (meth)acryloyl group, or the original unsaturated hydrocarbon group derived from the silicon compound as a raw material. As long as it is 50 mol % or less with respect to the amount corresponding to the group, there is no problem in carrying out the present invention, and it is preferably 30 mol % or less, more preferably 10 mol % or less. In formulas (A) and (B), the T unit is exemplified, but the same D unit, M unit, etc. may be used.

[Curable composition]
The curable composition of the present invention contains the silsesquioxane derivative of the present invention described above and a polymerization initiator.
The curable composition of the present invention may contain various components (hereinafter also referred to as "other components") as necessary.

(Polymerization initiator)
The polymerization initiator is not particularly limited, and examples thereof include photopolymerization initiators and thermal polymerization initiators. Photopolymerization initiators include, for example, radical photopolymerization initiators.
Thermal polymerization initiators include, for example, thermal radical polymerization initiators.
A known compound may be used as the photopolymerization initiator and the thermal polymerization initiator.

Photoradical polymerization initiators include 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxycyclohexylphenylketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1 -[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane- 1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, diethoxyacetophenone, oligo[2-hydroxy-2-methyl-1-[4-(1 -methylvinyl)phenyl]propanone] and acetophenones such as 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)benzyl]phenyl}-2-methyl-propan-1-one Compound; benzophenone compounds such as benzophenone, 4-phenylbenzophenone, 2,4,6-trimethylbenzophenone and 4-benzoyl-4'-methyldiphenylsulfide; methylbenzoyl formate, oxyphenylacetic acid 2-[2-oxo- α-Ketoester compounds such as 2-phenylacetoxyethoxy]ethyl ester and oxyphenylacetic acid 2-[2-hydroxyethoxy]ethyl ester; 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6 Phosphine oxide compounds such as -trimethylbenzoyl)phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide; benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl Benzoin compounds such as ether and benzoin isobutyl ether; titanocene compounds; 1-(4-(4-benzoylphenylsulfanyl)phenyl)-2-methyl-2-(4-methylphenylsulfinyl)propan-1-one Acetophenone/benzophenone hybrid photoinitiators; oxime ester photopolymerization initiators such as 1-(4-phenylthiophenyl)-2-(O-benzoyloxime)-1,2-octanedione; and camphorquinone. be done. These may be used alone or in combination of two or more.

The thermal radical polymerization initiator is not particularly limited, and examples include peroxides and azo initiators.

Examples of peroxides include hydrogen peroxide; inorganic peroxides such as sodium persulfate, ammonium persulfate and potassium persulfate; 1,1-bis(t-butylperoxy) 2-methylcyclohexane, 1,1-bis( t-hexylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-hexylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)-3,3,5-trimethyl cyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, 2,2-bis(4,4-di-butylperoxycyclohexyl)propane, 1,1-bis(t-butylperoxy)cyclododecane, t-hexylperoxyisopropyl monocarbonate, t-butylperoxymaleic acid, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, 2,5-dimethyl-2, 5-di(m-toluoylperoxy)hexane, t-butylperoxyisopropyl monocarbonate, t-butylperoxy 2-ethylhexylmonocarbonate, t-hexylperoxybenzoate, 2,5-dimethyl-2,5- Di(benzoylperoxy)hexane, t-butylperoxyacetate, 2,2-bis(t-butylperoxy)butane, t-butylperoxybenzoate, n-butyl-4,4-bis(t-butylperoxy) oxy)valerate, di-t-butylperoxyisophthalate, α,α'-bis(t-butylperoxy)diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butyl peroxy)hexane, t-butylcumyl peroxide, di-t-butylperoxide, p-menthane hydroperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, diisopropyl Organic peroxides such as benzene hydroperoxide, t-butyltrimethylsilyl peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-hexyl hydroperoxide, and t-butyl hydroperoxide things are mentioned.
These may be used alone or in combination of two or more.

Azo initiators include 2,2′-azobisisobutyronitrile, 1,1′-azobis(cyclohexane-1-carbonitrile), 2-(carbamoylazo)isobutyronitrile, 2-phenylazo-4 Azo compounds such as -methoxy-2,4-dimethylvaleronitrile, azodi-t-octane, azodi-t-butane, etc., may be used alone, or two or more of them may be used in combination.
Also, peroxides, ascorbic acid, sodium ascorbate, sodium erythorbate, tartaric acid, citric acid, metal salts of formaldehyde sulfoxylate, sodium thiosulfate, sodium sulfite, sodium bisulfite, sodium metabisulfite, ferric chloride A redox reaction can be achieved by combining with a redox polymerization initiation system using a reducing agent such as iron.

In the curable composition of the present invention, the content of the polymerization initiator is 0.01 parts by mass to 20 parts by mass with respect to 100 parts by mass of the silsesquioxane derivative represented by formula (1). is preferred, 0.1 to 10 parts by mass is more preferred, and 1 to 5 parts by weight is even more preferred.

(other ingredients)
Other components are not particularly limited, and examples include solvents, polymerizable compounds other than the silsesquioxane derivative represented by formula (1), resins, silicones, monomers, fillers, surfactants, antistatic agents ( For example, conductive polymer), leveling agent, photosensitizer, UV absorber, antioxidant, heat resistance improver, stabilizer, lubricant, pigment, dye, plasticizer, suspending agent, adhesion imparting agent, nano Examples include particles, nanofibers, nanosheets, and the like. The curable composition of the present invention may contain silane-based reactive diluents such as tetraalkoxysilanes, trialkoxysilanes, dialkoxysilanes, monoalkoxysilanes and disiloxanes.

The curable composition of the present invention may or may not contain a solvent.
Examples of the solvent include various organic solvents such as aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, chlorinated hydrocarbon solvents, alcohol solvents, ether solvents, amide solvents, ketone solvents, ester solvents and cellosolve solvents. be done.

The curable composition of the present invention may contain a polymerizable compound other than the silsesquioxane derivative represented by formula (1) (hereinafter also referred to as "other polymerizable compound"). You don't have to.
Other polymerizable compounds are not particularly limited as long as they are capable of undergoing a polymerization reaction in the presence of the silsesquioxane derivative represented by formula (1) and the polymerization initiator. Other polymerizable compounds include silsesquioxane derivatives other than the silsesquioxane derivative represented by formula (1), (meth)acrylate compounds, compounds having an ethylenically unsaturated group, epoxy compounds (having an epoxy group oxetanyl group-containing compounds), compounds having an oxetanyl group (oxetanyl group-containing compounds), and compounds having a vinyl ether group (vinyl ether compounds).

Examples of silsesquioxane derivatives other than the silsesquioxane derivatives represented by formula (1) include silsesquioxane derivatives consisting only of T units, silsesquioxane derivatives containing T units and D units, and the like. .

(Meth) acrylate compounds are not particularly limited, compounds having one (meth) acryloyl group (hereinafter also referred to as "monofunctional (meth) acrylate"), and compounds having two or more (meth) acryloyl groups (hereinafter also referred to as "polyfunctional (meth)acrylate").

Examples of monofunctional (meth)acrylates include
Alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate;
monofunctional (meth)acrylates having an alicyclic group such as cyclohexyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and tricyclodecanemethylol (meth)acrylate;
Monofunctional (meth)acrylates having aromatic groups of benzyl (meth)acrylate and phenyl (meth)acrylate;
(Meth)acrylates of phenol ethylene oxide adducts, (meth) acrylates of phenol propylene oxide adducts, (meth) acrylates of modified nonylphenol ethylene oxide adducts, and (meth) acrylates of nonylphenol propylene oxide adducts, paracumylphenol (meth)acrylates of alkylene oxide adducts of phenol derivatives, such as (meth)acrylates of alkylene oxide adducts, orthophenylphenol (meth)acrylates, and (meth)acrylates of alkylene oxide adducts of orthophenylphenol;
Monofunctional (meth)acrylates having an alkoxyalkyl group such as 2-ethylhexylcarbitol (meth)acrylate;
Monofunctional (meth)acrylates having a heterocyclic ring such as tetrahydrofurfuryl (meth)acrylate and N-(2-(meth)acryloxyethyl)hexahydrophthalimide;
hydroxyalkyl (meth)acrylates such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and hydroxyhexyl (meth)acrylate;
Monofunctional (meth)acrylates having a hydroxyl group and an aromatic group such as 2-hydroxy-3-phenoxypropyl (meth)acrylate;
Alkylene glycol mono(meth)acrylates such as diethylene glycol mono(meth)acrylate, dipropylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, tripropylene glycol mono(meth)acrylate; and ω-carboxypolycaprolactone monofunctional (meth)acrylates having a carboxy group such as mono(meth)acrylates and monohydroxyethyl (meth)acrylate phthalate;

Examples of polyfunctional (meth)acrylates include
Polyethylene glycol di(meth)acrylates such as diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate;
Polypropylene glycol di(meth)acrylates such as dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetrapropylene glycol di(meth)acrylate;
1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethylene oxide-modified neopentyl glycol di(meth)acrylate, ethylene oxide-modified bisphenol A di(meth)acrylate, propylene oxide-modified bisphenol A di(meth)acrylate, ethylene oxide-modified hydrogenated bisphenol A di(meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolpropane allyl ether di(meth)acrylate, trimethylolpropane tri(meth)acrylate , ethylene oxide-modified trimethylolpropane tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate and dipentaerythritol hexaacrylate. .

Urethane (meth)acrylates can also be used as polyfunctional (meth)acrylates.
Examples of urethane (meth)acrylate include a compound obtained by addition reaction of organic polyisocyanate and hydroxyl group-containing (meth)acrylate, and a compound obtained by addition reaction of organic polyisocyanate, polyol and hydroxyl group-containing (meth)acrylate. .
Monofunctional (meth)acrylates, polyfunctional (meth)acrylates, and the like may be used alone, or two or more of them may be used in combination, or different types may be used in combination.

Examples of polyols include low-molecular-weight polyols, polyether polyols, polyester polyols and polycarbonate polyols.
Low molecular weight polyols include ethylene glycol, propylene glycol, neopentyl glycol, cyclohexanedimethylol, 3-methyl-1,5-pentanediol, and the like.
Examples of polyether polyols include polypropylene glycol and polytetramethylene glycol.
As polyester polyols, reaction products of these low molecular weight polyols and/or polyether polyols with dibasic acids such as adipic acid, succinic acid, phthalic acid, hexahydrophthalic acid and terephthalic acid, or acid components such as anhydrides thereof is mentioned.
These may be used alone, or two or more of them may be used in combination, or different types may be used in combination.

Organic polyisocyanates include tolylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate.
Examples of hydroxyl group-containing (meth)acrylates include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; pentaerythritol tri(meth)acrylate; ) acrylates, di(meth)acrylates of isocyanuric acid 3-mol alkylene oxide adducts, and hydroxyl group-containing polyfunctional (meth)acrylates such as dipentaerythritol penta(meth)acrylates.
These may be used alone, or two or more of them may be used in combination, or different types may be used in combination.

In the curable composition of the present invention, when a (meth)acrylate compound is used in combination, the mixing ratio is not particularly limited, for example, 100 mass of the silsesquioxane derivative represented by the formula (1) The mixing ratio of the (meth)acrylate compound to 1 part is preferably 0 to 100 parts by mass, more preferably 0 to 50 parts by mass, even more preferably 0 to 20 parts by mass. From the viewpoint of adhesion to the inorganic substance layer, the mixing ratio of the (meth)acrylate compound is preferably low. , It is more preferable that it does not contain, or is 5% by mass or less with respect to the total amount of the composition, and it is more preferable that it does not contain or has a content of 1% by mass or less with respect to the total amount of the composition, Not containing is particularly preferred.

A compound having one ethylenically unsaturated group in one molecule other than the (meth)acrylate compound may be added to the curable composition.
The ethylenically unsaturated group is preferably a (meth)acryloyl group, a maleimide group, a (meth)acrylamide group, or a vinyl group.
Specific examples of the compound having an ethylenically unsaturated group include (meth)acrylic acid, a Michael addition type dimer of acrylic acid, N-(2-hydroxyethyl)citraconimide, N,N-dimethylacrylamide, acryloylmorpho Phosphorus, N-vinylpyrrolidone, N-vinylcaprolactam and the like.
These may be used alone or in combination of two or more.

Examples of epoxy compounds include monofunctional epoxy compounds and polyfunctional epoxy compounds.
Examples of oxetanyl group-containing compounds include monofunctional oxetane compounds and polyfunctional oxetane compounds.
Examples of vinyl ether compounds include monofunctional vinyl ether compounds and polyfunctional vinyl ether compounds.
As these compounds, for example, compounds described in JP-A-2011-42755 may be used.
The silicone is not particularly limited, and known silicones can be used. Examples include polydimethylsilicone, polydiphenylsilicone, polymethylphenylsilicone, etc., which have functional groups at their terminals and/or side chains. things are preferred. The functional group is not particularly limited, and examples thereof include (meth)acryloyl group, epoxy group, oxetanyl group, vinyl group, hydroxyl group, carboxy group, amino group, thiol group and the like.

When the curable composition of the present invention contains other polymerizable compounds, the content of the other polymerizable compounds is 0.01 per 100 parts by mass of the silsesquioxane derivative represented by formula (1). It is preferably from 0.1 to 50 parts by mass, even more preferably from 1 to 25 parts by mass.

[Cured product]
The cured product of the present invention is obtained by curing the aforementioned curable composition of the present invention. For example, the cured product of the present invention can be obtained by irradiating the curable composition of the present invention with an active energy ray or by heating the curable composition of the present invention.

In the cured product of the present invention, the contact angle of water at 25° C. is preferably 90° or more, more preferably 100° or more, and even more preferably 105° or more.
In the cured product of the present invention, the contact angle at 25°C can be measured by the method described in Examples below.
The upper limit of the contact angle of water at 25°C is not particularly limited, and may be, for example, 150° or less.

The cured product of the present invention preferably has a refractive index at 25° C. of less than 1.45, more preferably less than 1.42, even more preferably less than 1.4.
The lower limit of the refractive index at 25°C is not particularly limited, and may be, for example, 1.3 or more.
In the cured product of the present invention, the refractive index at 25°C can be measured by the method described in Examples below.

When curing the curable composition of the present invention, it may be after applying the curable composition to the substrate.
The curable composition of the present invention may or may not contain a solvent. When a solvent is included, it is preferable to cure after removing the solvent.
By applying the curable composition to the substrate and then curing the curable composition, a substrate having a cured product can be obtained.

When applying the curable composition of the present invention to a substrate, the method of applying the curable composition is not particularly limited. Examples of coating methods include ordinary coating methods such as casting, spin coating, bar coating, dip coating, spray coating, roll coating, flow coating and gravure coating.
The thickness to which the curable composition of the present invention is applied is not particularly limited, and is appropriately set according to the purpose.
The substrate to which the curable composition of the present invention is applied is not particularly limited, and examples thereof include wood, metal, inorganic materials, plastics, paper, fibers and fabrics.
Metals include copper, silver, iron, aluminum, silicon, silicon steel and stainless steel. Examples of inorganic materials include metal oxides such as aluminum oxide, silicon oxide, magnesium oxide, zirconium oxide, zinc oxide, indium tin oxide and gallium oxide; metal nitrides such as aluminum nitride, gallium nitride and silicon nitride; silicon carbide and nitride; Examples include ceramics such as boron, mortar, concrete and glass.
Specific examples of plastics include acrylic resins such as polymethyl methacrylate, polyester resins such as polyethylene terephthalate, polyvinyl chloride resins, polycarbonate resins, epoxy resins, polyamide resins such as nylon and aramid, polyimide resins, polyamideimide resins, 4-fluoro Fluorine resins such as ethylene chloride resins, polyolefin resins such as crosslinked polyethylene resins, vinylidene chloride resins, acrylonitrile-butadiene-styrene (ABS) resins, polystyrene resins, polyacrylonitrile resins, cycloolefin polymers (COP), cycloolefin copolymers (COC) , acetate resins, polyarylates, cellophane, norbornene resins, acetyl cellulose resins such as triacetyl cellulose (TAC), polychloroprene, polyphenylene sulfide, polysulfone, polyether sulfone, polyether ether ketone, polyurethane resin, glass epoxy resin, etc. composite resins, various fiber-reinforced resins, and the like.
Examples of fibers include natural fibers, regenerated fibers, semi-synthetic fibers, metal fibers, glass fibers, carbon fibers, ceramic fibers and known chemical fibers. The fabric may be woven or non-woven, and may be made, for example, using the fibers described above.
These materials may be used alone, or two or more of them may be combined, mixed, or composited for use.
The shape of the substrate is not particularly limited, and examples thereof include plate-like, sheet-like, film-like, rod-like, spherical, fiber-like, powder-like, lens-like and other regular or irregular shapes.

(Curing method)
In the present invention, the curing method and curing conditions are selected depending on whether the curable composition is active energy ray-curable and/or thermosetting. Further, the curing conditions (in the case of active energy ray curing, for example, the type of light source and the amount of light irradiation, and in the case of thermosetting, heating temperature, heating time, etc.) It is appropriately selected depending on the type and amount of the polymerization initiator to be contained, the type of other polymerizable compound, and the like.

(1) Active energy ray curing method When the present composition is an active energy ray curable composition, the curing method may be irradiation with an active energy ray using a known active energy ray irradiation device or the like. Examples of active energy rays include electron beams, and light such as ultraviolet rays, visible rays, and X-rays. Light is preferred, and ultraviolet rays are more preferred from the viewpoint that inexpensive devices can be used.
Ultraviolet irradiation devices include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, ultraviolet (UV) electrodeless lamps, chemical lamps, black light lamps, microwave-excited mercury lamps, and light-emitting diodes (LEDs). mentioned.
The intensity of light irradiation to the film coated with the present composition may be selected according to the purpose, application, etc. The light irradiation intensity in the light wavelength range effective for polymerization (light with a wavelength of 220 nm to 460 nm is preferably used, although it varies depending on the type of photopolymerization initiator) is 0.1 mW/cm ² to 1000 mW/cm ² . Preferably.
Also, the irradiation energy should be set as appropriate according to the type of active energy ray, the compounding composition, and the like. The light irradiation time to the coating may also be selected according to the purpose, application, etc., and the integrated light amount represented as the product of the light irradiation intensity and the light irradiation time in the light wavelength region is 10 mJ/cm ² to 7, It is preferable to set the light irradiation time so as to achieve 000 mJ/cm ² . The integrated amount of light is more preferably 200 mJ/cm ² to 5,000 mJ/cm ² and even more preferably 500 mJ/cm ² to 4,000 mJ/cm ² . When the integrated amount of light is within the above range, curing of the composition proceeds smoothly, and a uniform cured product can be easily obtained.

Also, heat curing can be appropriately combined before and/or after photocuring.
For example, after impregnating the present composition into a substrate having a portion that is shaded when irradiated with light, the composition is first cured in the portion exposed to light by irradiating light, and then, A two-stage cure can also be performed in which heat is applied to cure the composition in the areas not exposed to light. Such substrates are not particularly limited, and examples thereof include substrates having complex shapes such as fabric, fibrous, powdery, porous, and uneven shapes, and two or more of these shapes. may be combined.

(2) Thermosetting method When the present composition is a thermosetting composition, its curing method and curing conditions are not particularly limited.
The curing temperature is preferably 80°C to 200°C, more preferably 100°C to 180°C, even more preferably 110°C to 150°C. The curing temperature may be constant or may be increased. You may combine temperature rise and temperature fall.
The curing time is appropriately selected according to the type of thermal polymerization initiator and the content of other components, and is preferably 10 minutes to 360 minutes, more preferably 30 minutes to 300 minutes, and even more preferably 60 minutes to 240 minutes. By curing the composition under the above preferable conditions, a uniform cured film free from blisters, cracks and the like can be formed.

(Uses of silsesquioxane derivatives, etc.)
The cured product obtained using the silsesquioxane derivative of the present invention has a large contact angle with water, antifouling properties such as high water repellency, and high releasability. Furthermore, when the curable composition containing the silsesquioxane derivative of the present invention is applied to a substrate and then the curable composition is cured, the adhesion between the resulting cured product and the substrate is excellent. The cured product has excellent adhesion to the above-mentioned "substrate to which the curable composition of the present invention is applied", and has excellent adhesion to glass, plastic, and the like, for example.
The silsesquioxane derivative of the present invention and the curable composition containing the same have low viscosity, so that they are excellent in solvent-free coating properties, and even when using a solvent, the amount used can be reduced. can do.
INDUSTRIAL APPLICABILITY The silsesquioxane derivative of the present invention and the curable composition containing the same are inhibited from increasing in viscosity over time and under high temperature conditions, and have good storage stability.
In the silsesquioxane derivative of the present invention, since the structural unit (c) containing a fluorine atom is introduced, the cured product obtained using the silsesquioxane derivative of the present invention exhibits heat resistance, chemical resistance, It tends to be excellent in weather resistance and the like.

The silsesquioxane derivative of the present invention can be applied to applications requiring antifouling properties such as water repellency, releasability, adhesion, heat resistance, chemical resistance, weather resistance, and the like.
The silsesquioxane derivative of the present invention can be applied to, for example, optical lenses, displays, optical discs, low refractive index materials for optical fibers, antireflection materials, release films, replica molds, adhesives, and the like.

Releasability is essential for nanoimprint replica molds, but if a replica mold is produced using a composition containing a release agent, the release agent may bleed during use.
On the other hand, in the silsesquioxane derivative of the present invention, the structural unit (c) contributing to releasability is introduced into the silsesquioxane derivative, and there is no need to use a release agent.

The silsesquioxane derivatives of the present invention do not necessarily require formulations other than initiators.
Since the silsesquioxane derivative of the present disclosure and the curable composition containing the same have low viscosity, they can be easily applied. It can be used for fouling coating agent compositions and the like.
Since the silsesquioxane derivative of the present disclosure and the curable composition containing the same have low viscosity, they can be suitably used for applications requiring low viscosity. For example, it can be applied to adhesive applications, inkjet printing, printing applications such as 3D printing, coating agent applications, nanoprinting applications, and the like. Moreover, when applied to nanoprinting, the silsesquioxane derivative of the present invention has a low viscosity and is therefore excellent in fine transfer properties. Moreover, since the silsesquioxane derivative of the present invention can be used without a solvent, it can be cured as it is after being poured into a mold.
The silsesquioxane derivative of the present invention may be used in combination with fillers, other polymerizable compounds and the like. Moreover, since the silsesquioxane derivative of the present invention has a low viscosity, it can be mixed with a large amount of filler.

Next, the present invention will be specifically described based on examples and comparative examples. The invention is not limited to the following examples. "-" in Table 1 means that the corresponding physical properties have not been measured.

(Measurement of weight average molecular weight)
The weight average molecular weight (Mw) of the silsesquioxane derivative in each example and each comparative example was measured as follows. Specifically, by gel permeation chromatography (manufactured by Tosoh Corporation, HLC-8320GPC, hereinafter abbreviated as "GPC"), in a tetrahydrofuran solvent at 40 ° C., a GPC column "TSK gel SuperMultiporeHZ-M" (manufactured by Tosoh Corporation ), and the molecular weight in terms of standard polystyrene was calculated from the retention time.

(Measurement of viscosity before accelerated test)
The silsesquioxane derivatives in each example and each comparative example were measured for viscosity at 25° C. using a TVE22H viscometer manufactured by Toki Sangyo Co., Ltd.

(Measurement of viscosity after accelerated test)
1 g of the silsesquioxane derivative in each example and each comparative example was weighed into a 9 mL screw tube bottle and allowed to stand in a constant temperature bath at 60° C. for 7 days. Thereafter, the viscosity at 25° C. was measured in the same manner as described above (measurement of viscosity before accelerated test), and the viscosity obtained by measurement was taken as the viscosity after accelerated test.

(Calculation of molar ratio of each structural unit of silsesquioxane derivative)
Regarding the molar ratio of each structural unit of the silsesquioxane derivative in each example and each comparative example, a sample dissolved in heavy chloroform was subjected to ¹ H-NMR analysis, and if necessary, further ²⁹ Si-NMR analysis. It was calculated by also performing

<Example 1>
(Synthesis of silsesquioxane derivative 1)
Into a 200 mL four-necked round-bottomed flask equipped with a thermometer, dropping funnel and stirring blade, (3-acryloyloxy)propyltrimethoxysilane (5.98 g, 25.5 mmol, corresponding to structural unit (b)), triethoxy -1H,1H,2H,2H-tridecafluoro-n-octylsilane (13.0 g, 25.5 mmol, corresponding to structural unit (c)), 4-methoxyphenol (0.003 g) and 2-propanol (45 .0 g) was weighed out and the mixture was stirred at room temperature. Separately, 35% hydrochloric acid (0.063 g, 0.61 mmol) and water (2.7 g) were mixed to prepare an aqueous solution. After stirring the reaction solution while dropping the aqueous solution prepared in the mixed solution from the dropping funnel over about 1 hour, 1,3-divinyltetramethyldisiloxane (2.38 g, 12.75 mmol, to the structural unit (f) corresponding) was added and allowed to stand overnight. Thereafter, the solvent and the like in the reaction solution were distilled off under reduced pressure while the reaction solution was heated to 60° C. to obtain 16.9 g of a colorless transparent liquid silsesquioxane derivative 1 (S1). By ¹ H-NMR analysis of S1, it was confirmed that each structural unit was introduced quantitatively according to the charging ratio of the raw materials. The synthesized silsesquioxane derivative 1 had a viscosity of 814 mPa·s at 25° C. (before the accelerated test) and a weight average molecular weight (Mw) of 2,580. Also, the viscosity at 25° C. after the accelerated test was 891 mPa·s.

<Example 2>
A silsesquioxane derivative 2 (S2) was obtained in the same manner as in Example 1, except that the amounts of raw materials charged were changed to those in Example 1 and changed as shown in Table 1, and the amounts of the solvent and the like were changed as appropriate. . By ¹ H-NMR analysis of S2, it was confirmed that each structural unit was introduced quantitatively according to the charging ratio of the raw materials.
Regarding the synthesized silsesquioxane derivative 2, Table 1 shows the molar ratio of each structural unit in the silsesquioxane derivative, the viscosity at 25°C (before accelerated test), and the weight average molecular weight (Mw).

<Comparative Examples 1 to 4>
Silsesquioxane derivatives 3 to 6 (S3 to S6 ). In Comparative Example 4, hexamethyldisiloxane (corresponding to the structural unit (g)) was used instead of 1,3-divinyltetramethyldisiloxane as a raw material constituting the M unit of the silsesquioxane derivative. ¹ H-NMR analysis of S3 to S6 confirmed that each structural unit was introduced quantitatively according to the charging ratio of the raw materials.
Regarding the synthesized silsesquioxane derivatives 3 to 6, the molar ratio of each structural unit in the silsesquioxane derivative, the viscosity at 25° C. (before and after the accelerated test) and the weight average molecular weight (Mw) are shown in Table 1. show.

Using the silsesquioxane derivatives 1 to 6 synthesized as described above, photocurable compositions 1 to 6 were prepared as follows. Adhesion test, contact angle measurement and refractive index measurement were performed using the prepared photocurable compositions 1 to 6, respectively. Details are described below.

(Preparation of photocurable composition)
0.09 part by mass of 2-hydroxy-2-methyl-1-phenylpropan-1-one is added to 1 to 33 parts by mass of the synthesized silsesquioxane derivative, and the mixture is stirred with a rotation/revolution mixer. By doing so, photocurable compositions 1 to 3 were prepared. Photocurable Compositions 1 to 3 do not substantially contain a solvent since the solvent and the like are removed by distillation during the synthesis of Silsesquioxane Derivatives 1 to 3.

(Preparation of photocured film)
Each of the photocurable compositions 1 to 6 was placed on a white plate glass as a substrate, and No. After each application using a No. 8 bar coater, UV irradiation was performed under the following conditions to prepare a photocured film. Each film thickness was about 5 μm.
[Ultraviolet irradiation conditions]
Lamp: High pressure mercury lamp Height: 10cm
Conveyor speed: 5.75m/min
Accumulated amount of light per pass: 360 mJ/cm ² (UV-A)
Atmosphere: Atmosphere Number of passes: 10 times

(Adhesion test)
An adhesion test was performed on the photocured film prepared as described above in accordance with JIS K5600-5-6. It represents the number of squares remaining without peeling out of 25 squares, and the larger the number, the higher the adhesion to the substrate. Table 1 shows the results.

(Measurement of contact angle)
For the photocured film prepared as described above, the contact angle with respect to pure water at 24° C. was measured using OCA20 manufactured by Eko Seiki Co., Ltd. A larger contact angle indicates better water repellency. Table 1 shows the results.

(Measurement of refractive index)
A formwork was prepared from a silicone rubber sheet with a thickness of 1 mm, a PET film was placed on a glass plate, and the formwork was further placed. Each of the photocurable compositions 1 to 6 was poured into this mold, and the mold was covered with a PET film and a glass plate to prevent air bubbles from entering. Photocurable compositions 1 to 6 covered with a PET film and a glass plate are cured to a thickness of 1 mm by changing the number of passes to 20 under the same ultraviolet irradiation conditions as described above (Preparation of photocured film). made each one.
Using an Abbe refractometer NAR-1T manufactured by Atago Co., Ltd., the refractive index was determined at 25° C. with a light source of 589 nm for the cured product having a thickness of 1 mm. Table 1 shows the results.

As shown in Table 1, Examples 1 and 2 had better adhesion results than Comparative Examples 1, 3 and 4.
Examples 1 and 2 gave better contact angle and refractive index results than Comparative Example 2.

The disclosure of Japanese Patent Application No. 2021-195434 filed on December 1, 2021 is incorporated herein by reference in its entirety.
All publications, patent applications and technical standards mentioned herein are to the same extent as if each individual publication, patent application and technical standard were specifically and individually noted to be incorporated by reference. incorporated herein by reference.

Claims (8)

1. A silsesquioxane derivative represented by the following formula (1).
   

   

   
   [In the formula (1), R ¹ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and R ² is an alkylene group having 1 to 10 carbon atoms, a cycloalkylene group having 3 to 10 carbon atoms, a carbon an arylene group having 6 to 10 atoms or an aralkylene group having 7 to 12 carbon atoms, R ³ being a fluoro group or a fluoroalkyl group having 1 to 20 carbon atoms, and R ⁴ and R ⁵ each independently hydrogen atom, saturated or unsaturated alkyl group having 1 to 20 carbon atoms, saturated or unsaturated cycloalkyl group having 3 to 8 carbon atoms, aryl group having 6 to 20 carbon atoms or 7 to 20 carbon atoms is an aralkyl group, R ⁶ is an organic group having 2 to 12 carbon atoms having at least one of an ethylenically unsaturated bond and a carbon-carbon triple bond, and R ⁷ and R ⁸ each independently have 1 to an alkyl group having 10 carbon atoms, an aryl group having 6 to 10 carbon atoms or an aralkyl group having 7 to 10 carbon atoms, wherein a plurality of R ⁵ may be the same or different, and a plurality of R ⁷ may be the same may be different, multiple R ⁸ may be the same or different, each of R ¹ to R ⁸ may be independently partially substituted with a substituent or a halogen atom, u, v and y are positive numbers and t, w, x and z are each independently 0 or a positive number. ]
2. The silsesquioxane derivative according to claim 1, wherein t, w, x and z in the formula (1) are 0 and 0.01≤y/(u+v)≤1.
3. The silsesquioxane derivative according to claim 1 or claim 2, which has a viscosity at 25°C of 10 mPa·s to 7,000 mPa·s.
4. A curable composition comprising the silsesquioxane derivative according to any one of claims 1 to 3 and a polymerization initiator.
5. A cured product obtained by curing the curable composition according to claim 4.
6. The cured product according to claim 5, which has a contact angle with water of 100° or more at 25°C.
7. The cured product according to claim 5 or 6, which has a refractive index of less than 1.42 at 25°C.
8. A substrate comprising the cured product according to any one of claims 5 to 7.