Silylated polysilsesquioxane, production method thereof, and use thereof

Abstract

To provide a silylated polysilsesquioxane capable of providing a cured product having a low dielectric constant.SOLUTION: A silylated polysilsesquioxane comprises a structural unit (A) represented by the general formula (1), [R1SiO1.5], and a structural unit (B) represented by the general formula (2), [R2R3SiO1.0], and has at least one trialkylsilyl group. In the formula (1), R1 represents an alkyl group, an aryl group, or a 3-(meth)acryloxypropyl group. In the formula (2), R2 and R3 are the same or different and represent an alkyl group, an aryl group, or a 3-(meth)acryloxypropyl group.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a silylated polysilsesquioxane, a method for producing the same, and uses thereof. More specifically, the present invention relates to a silylated polysilsesquioxane that gives a cured product with a low dielectric constant, a method for producing the same, and uses thereof. [Background technology]

[0002] In recent years, the frequencies of electric and electronic devices, such as communication devices like mobile phones, network-related devices like servers, and electronic devices like computers, have become increasingly higher, requiring materials used in these devices to adapt to these changes. While materials with low dielectric constants have been used for insulating films in these devices to reduce transmission loss, materials with even lower dielectric constants are required as frequencies increase. Furthermore, insulating films must be heat-resistant during the manufacturing process and use of electric and electronic devices. Furthermore, flexible devices, such as flexible displays, are seeing rapidly expanding demand, and insulating films must be strong against deformations such as tension and bending, e.g., have high elongation. Polyimide-based materials have been proposed as insulating film materials for such electric and electronic devices (e.g., Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-130281 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-195966 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the laminated polyimide film described in Patent Document 1 actually has a dielectric constant of only about 3.5 at a measurement frequency of 1 MHz, with the lowest example being 3.45. In recent years, as frequencies have become higher, materials with even lower dielectric constants are required, but the laminated polyimide film described in Patent Document 1 does not yet fully satisfy this requirement. Patent Document 2 lists the physical properties of a cured coating film made from a thermosetting polyimide resin composition using a specific polyimide resin in Table 3, etc., but the elongation at break is low and the flexibility is not sufficient. Thus, no material is yet known that can satisfy both the dielectric constant and elongation in the high-frequency range required for insulating films that can accommodate the increasing frequency and flexibility of electric and electronic devices.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a silylated polysilsesquioxane that can give a cured product having a low dielectric constant, high elongation, and excellent flexibility. [Means for solving the problem]

[0006] The present inventors have conducted extensive research into low dielectric materials and have found that a cured product with a low dielectric constant can be obtained by using a polysilsesquioxane containing specific structural units and having at least one trialkylsilyl group, which has led to the completion of the present invention.

[0007] That is, the present invention includes the following aspects. <1> A silylated polysilsesquioxane comprising a structural unit (A) represented by the following general formula (1) and a structural unit (B) represented by the following general formula (2), and characterized by having at least one trialkylsilyl group: [R 1 SiO 1.5 ] (1) (In formula (1), R 1 represents an alkyl group, an aryl group, or a 3-(meth)acryloxypropyl group. [R 2 R 3 SiO 1.0 ] (2) (In formula (2), R 2 and R 3 are the same or different and represent an alkyl group, an aryl group, or a 3-(meth)acryloxypropyl group. <2> The silylated polysilsesquioxane is characterized in that the content of trialkylsilyl groups in the silylated polysilsesquioxane is 10 mol % or more relative to 100 mol % in total of the trialkylsilyl groups and the hydroxyl groups bonded to silicon atoms. <1> The silylated polysilsesquioxane according to claim 1. <3> The structural unit (A) is R in the general formula (1). 1 is an alkyl group having 3 to 10 carbon atoms, and R 1 and (a2) a structural unit in which (a1) is an aryl group. <1> or <2> The silylated polysilsesquioxane according to claim 1. <4> The silylated polysilsesquioxane is a trialkylsilylated product of polysilsesquioxane, and the polysilsesquioxane is characterized in that the carbon content of the alkyl group of the structural unit (a1) is 3% by mass or more relative to 100% by mass of the total carbon content of the polysilsesquioxane. <3> The silylated polysilsesquioxane according to claim 1. <5> The content of the structural unit (A) is 10 mol % or more relative to 100 mol % of all structural units of the silylated polysilsesquioxane. <1> ~ <4> The silylated polysilsesquioxane according to any one of the preceding items. <6> the above <1> ~ <5> 1. An optical material comprising the silylated polysilsesquioxane according to any one of claims 1 to 9. <7> the above <1> ~ <5> A low dielectric material comprising the silylated polysilsesquioxane according to any one of the preceding items. <8> A method for producing a silylated polysilsesquioxane, comprising a step of trialkylsilylating a polysilsesquioxane, wherein the polysilsesquioxane comprises a structural unit (A) represented by the following general formula (1) and a structural unit (B) represented by the following general formula (2): [R 1 SiO1.5 ] (1) (In formula (1), R 1 represents an alkyl group, an aryl group, or a 3-(meth)acryloxypropyl group. [R 2 R 3 SiO 1.0 ] (2) (In formula (2), R 2 and R 3 are the same or different and represent an alkyl group, an aryl group, or a 3-(meth)acryloxypropyl group. <9> The trialkylsilylation step is carried out by reacting the polysilsesquioxane with a trialkylsilylation agent, and the trialkylsilylation agent is a compound represented by the following general formula (6): <8> 1. A method for producing the silylated polysilsesquioxane according to claim 1. R 7 R 8 R 9 Si-X (6) (In formula (6), R 7 , R 8 and R 9 are the same or different and represent an alkyl group; X represents a hydrogen atom, a chlorine atom, an alkoxy group, a hydroxyl group, or —NH—SiR 10 R 11 R 12 Represents R 10 , R 11 and R 12 are the same or different and represent an alkyl group. <10> The trialkylsilylating agent is hexamethyldisilazane. <9> 1. A method for producing the silylated polysilsesquioxane according to claim 1. <11> The method according to any one of the preceding claims, further comprising a step of synthesizing polysilsesquioxane by subjecting the organosilane compound to a hydrolysis-condensation reaction. <8> ~ <10> 1. A method for producing the silylated polysilsesquioxane according to any one of the preceding claims. [Effects of the Invention]

[0008] The silylated polysilsesquioxane of the present invention can give a cured product having a low dielectric constant and excellent flexibility. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention will be described in detail below. Note that a combination of two or more of the individual preferred embodiments of the present invention described below is also a preferred embodiment of the present invention.

[0010] 1. Silylated polysilsesquioxane The silylated polysilsesquioxane of the present invention is characterized by comprising a structural unit (A) represented by the following general formula (1) and a structural unit (B) represented by the following general formula (2), and having at least one trialkylsilyl group. [R 1 SiO 1.5 ] (1) (In formula (1), R 1 represents an alkyl group, an aryl group, or a 3-(meth)acryloxypropyl group. [R 2 R 3 SiO 1.0 ] (2) (In formula (2), R 2 and R 3 are the same or different and represent an alkyl group, an aryl group, or a 3-(meth)acryloxypropyl group.

[0011] The silylated polysilsesquioxane of the present invention has a trimethylsilyl group with low polarity, and thus can give a cured product with a low dielectric constant.

[0012] Furthermore, since the silylated polysilsesquioxane of the present invention has trimethylsilyl groups, it has fewer hydroxyl groups than ordinary polysilsesquioxanes. As a result, the crosslinking reaction does not proceed excessively during crosslinking, and a cured product having high elongation and appropriate flexibility can be obtained.

[0013] Each of the constituent units that make up the silylated polysilsesquioxane of the present invention will now be described. <Constituent unit (A)> In the above general formula (1), R 1 represents an alkyl group, an aryl group, or a 3-(meth)acryloxypropyl group. The alkyl group may be linear or branched, but is preferably linear in order to improve thermal decomposition resistance. The number of carbon atoms in the alkyl group is preferably 1 to 18, more preferably 1 to 10, and even more preferably 3 to 10, in order to improve adhesion to the substrate.

[0014] Examples of the aryl group include a phenyl group, a tolyl group, a xylyl group, a biphenylyl group, a naphthyl group, a phenanthryl group, etc. Among these, a phenyl group is preferred because of its good solubility in organic solvents.

[0015] The above 3-(meth)acryloxypropyl group refers to a 3-acryloxypropyl group represented by CH2=CH-CO-O-(CH2)3- and a 3-methacryloxypropyl group represented by CH2=CCH3-CO-O-(CH2)3-.

[0016] Above R 1 Among these, alkyl groups and aryl groups are preferred, and alkyl groups are more preferred, in that they can reduce shrinkage of the coating film.

[0017] The silylated polysilsesquioxane may have only one type of the structural unit (A), or may have two or more types. The silylated polysilsesquioxane is preferably selected from the group consisting of the structural unit (A) R 1 is a structural unit (a1) in which R is an alkyl group having 3 to 10 carbon atoms; 1 and a structural unit (a2) in which the structural unit (a1) is an aryl group.

[0018] The content of the structural unit (A) is preferably 10 mol% or more, and more preferably 10 mol% or more but less than 90 mol%, relative to 100 mol% of all structural units in the silylated polysilsesquioxane. If the content of the structural unit (A) is 90 mol% or more, the proportion of the structural unit (B) represented by general formula (2), which contributes to improving flexibility, decreases, and the coating film may become hard and brittle. In terms of easily achieving a balance between thermal decomposition resistance and flexibility, the content of the structural unit (A) is more preferably 10 to 80 mol%, and particularly preferably 20 to 60 mol%, relative to 100 mol% of all structural units in the silylated polysilsesquioxane.

[0019] The silylated polysilsesquioxane is 1 is a structural unit (a1) in which R is an alkyl group having 3 to 10 carbon atoms; 1 When the silylated polysilsesquioxane contains a structural unit (a1) in which the aryl group is a structural unit (a2), the content of the structural unit (a1) is preferably 1 to 40 mol%, and more preferably 5 to 20 mol%, relative to 100 mol% of all structural units in the silylated polysilsesquioxane. The content of the structural unit (a2) is preferably 1 to 80 mol%, and more preferably 5 to 40 mol%, relative to 100 mol% of all structural units.

[0020] <Constituent Unit (B)> In the above general formula (2), R 2 and R 3 are the same or different and represent an alkyl group, an aryl group, or a 3-(meth)acryloxypropyl group.

[0021] R 2 and R 3 The alkyl group represented by the formula (I) may be linear or branched. The number of carbon atoms in the alkyl group is preferably 1 to 3, in order to achieve a low dielectric constant.

[0022] R 2 and R 3 The aryl group represented by the formula (I) is the same as the above-mentioned R 1Among the aryl groups, a phenyl group is preferred.

[0023] Among them, R 2 , R 3 is preferably an alkyl group.

[0024] The silylated polysilsesquioxane may have only one type of the structural unit (B), or may have two or more types.

[0025] The content of the structural unit (B) is preferably 10 to 80 mol %, more preferably 20 to 60 mol %, and even more preferably 30 to 50 mol %, relative to 100 mol % of all structural units in the silylated polysilsesquioxane.

[0026] <Constituent Unit (C)> The silylated polysilsesquioxane may further contain a structural unit (C) represented by the following formula (3). [R 4 R 5 R 6 SiO 0.5 ] (3) (R 4 , R 5 and R 6 are the same or different and represent an alkyl group, an aryl group, or a 3-(meth)acryloxypropyl group.

[0027] R 4 , R 5 , R 6 The alkyl group represented by the formula (I) may be linear or branched. The number of carbon atoms in the alkyl group is preferably 1 to 3, in order to achieve a low dielectric constant.

[0028] R 4 , R 5 , R 6 The aryl group represented by the formula (I) is the same as the above-mentioned R 1 Among them, a phenyl group is preferred because of its good solubility in organic solvents.

[0029] Among them, R 4 , R 5 , R 6 is more preferably an alkyl group.

[0030] The silylated polysilsesquioxane may have only one type of the structural unit (C), or may have two or more types.

[0031] The content of the structural unit (C) is preferably 0.5 to 20 mol %, more preferably 1 to 10 mol %, and even more preferably 2 to 6 mol %, relative to 100 mol % of all structural units in the silylated polysilsesquioxane.

[0032] <Constituent Unit (D)> The silylated polysilsesquioxane may further contain a structural unit (D) other than the above-mentioned structural units (A), (B), and (C). Examples of the structural unit (D) include a structural unit (D1) represented by the following general formula (4), a structural unit (D2) represented by the following general formula (5), and a structural unit (D3) represented by the following general formula (6). [R 1 XSiO 1.0 ] (4) (In the formula, R 1 is the same as above. X represents an alkoxy group, a halogen atom, a hydrogen atom, or a hydroxyl group. [R 1 X2SiO 0.5 ] (5) (In the formula, R 1 is the same as above. X represents an alkoxy group, a halogen atom, a hydrogen atom, or a hydroxyl group. [R 2 R 3 YSiO 0.5 ] (6) (In the formula, R 2 and R 3 is the same as above. Y represents an alkoxy group, a halogen atom, a hydrogen atom, or a hydroxyl group.

[0033] The number of carbon atoms in the alkoxy group represented by X is preferably 1 to 2, since it is easily eliminated and can contribute to a crosslinking point.

[0034] The number of carbon atoms in the alkoxy group represented by Y is preferably 1 to 2, since it is easily eliminated and can contribute to a crosslinking point.

[0035] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0036] The content of the structural unit (D) is preferably 0 to 50 mol %, more preferably 5 to 40 mol %, and even more preferably 10 to 30 mol %, relative to 100 mol % of all structural units in the silylated polysilsesquioxane.

[0037] <Trialkylsilyl group> The silylated polysilsesquioxane of the present invention has at least one trialkylsilyl group. The silylated polysilsesquioxane is preferably one in which the trialkylsilyl group is bonded to a silicon atom of the polysilsesquioxane. The silylated polysilsesquioxane may have the trialkylsilyl group at the terminal, at the side chain, or at both the terminal and the side chain.

[0038] The trialkylsilyl group is —SiR 7 R 8 R 9 It is a group represented by the following formula: R 7 , R 8 and R 9 are the same or different and represent an alkyl group. The alkyl group may be linear or branched, but is preferably linear in that it improves thermal decomposition resistance. The alkyl group preferably has 1 to 3 carbon atoms in order to reduce the dielectric constant.

[0039] Among them, R 7 , R 8 and R9 The alkyl group represented by the formula (I) is preferably a methyl group, an ethyl group, an n-propyl group, or an isopropyl group, more preferably a methyl group or an ethyl group, and even more preferably a methyl group. R 7 , R 8 and R 9 and are more preferably the same alkyl group.

[0040] The content of trialkylsilyl groups in the silylated polysilsesquioxane is preferably 10 mol % or more, based on 100 mol % of the total of the trialkylsilyl groups and the hydroxyl groups bonded to silicon atoms. When the content of trialkylsilyl groups is within the above range, the cured product has an even lower dielectric constant. In addition, the cured product has greater elongation and excellent flexibility. The content of trialkylsilyl groups is preferably 10 to 60 mol %, more preferably 15 to 50 mol %, and even more preferably 20 to 40 mol %, based on 100 mol % of the total of the trialkylsilyl groups and the hydroxyl groups bonded to silicon atoms. The amount of the trialkylsilyl group or the hydroxyl group bonded to the silicon atom can be determined by 29Si-NMR measurement, specifically by the method described in the Examples below.

[0041] The silylated polysilsesquioxane having at least one trialkylsilyl group can be obtained, for example, by trialkylsilylating the hydroxyl group of a polysilsesquioxane.

[0042] In the polysilsesquioxane (polysilsesquioxane before silylation), the carbon content of the alkyl group of the structural unit (a1) is preferably 3% by mass or more, relative to 100% by mass of the total carbon content of the polysilsesquioxane. When the carbon content is within the above range, the flexibility of the cured product of the polysilsesquioxane after silylation is improved. In terms of further improving flexibility, the carbon content is more preferably 3 to 40% by mass, even more preferably 3 to 30% by mass, and even more preferably 3 to 20% by mass of the total carbon content of the polysilsesquioxane.

[0043] The silylated polysilsesquioxane may have any of a random structure, a ladder structure, and a cage structure, but among these, a random structure is preferred in terms of thermosetting properties.

[0044] The weight average molecular weight of the silylated polysilsesquioxane is preferably 3,000 to 100,000, more preferably 3,000 to 50,000, and even more preferably 3,000 to 20,000, in view of excellent coating properties on substrates. The weight average molecular weight can be determined by gel permeation chromatography (GPC), specifically by the method described in the examples below.

[0045] 2. Method for producing silylated polysilsesquioxane The method for producing the silylated polysilsesquioxane of the present invention is not particularly limited, and any known method may be used, but it is preferable that the method includes a step of trialkylsilylating the polysilsesquioxane. The polysilsesquioxane includes the above-described structural unit (A) and structural unit (B). Such a method for producing a silylated polysilsesquioxane, which includes a step of trialkylsilylating the polysilsesquioxane, also constitutes one aspect of the present invention.

[0046] The step of trialkylsilylating the polysilsesquioxane can be carried out by reacting the polysilsesquioxane with a trialkylsilylating agent. The silylation reaction can be carried out by adding the trialkylsilylating agent to the polysilsesquioxane and heating the mixture.

[0047] The trialkylsilylation agent is not particularly limited as long as it is a compound that can trialkylsilylate the silicon-bonded hydroxyl groups of polysilsesquioxane. However, in terms of good reaction efficiency, a compound represented by the following general formula (6) is preferred. R 7 R 8 R 9 Si-X (6) (In formula (6), R 7 , R 8 and R 9 are the same or different and represent an alkyl group, and X represents a hydrogen atom, a chlorine atom, an alkoxy group having 1 to 3 carbon atoms, a hydroxyl group, or -NH-SiR 10 R 11 R 12 Represents R 10 , R 11 and R 12 are the same or different and represent an alkyl group.

[0048] R 7 , R 8 , R 9 is the same as above.

[0049] R 10 , R 11 and R 12 The alkyl group represented by the formula (I) is preferably a methyl group, an ethyl group, an n-propyl group, or an isopropyl group, more preferably a methyl group or an ethyl group, and even more preferably a methyl group.

[0050] Among these, X is preferably a hydrogen atom, a chlorine atom, an alkoxy group having 1 to 3 carbon atoms, or —NH—SiR because it can lower the reaction temperature. 10 R 11 R 12is preferably —NH—SiR 10 R 11 R 12 It is more preferable that:

[0051] The trialkylsilylating agent is more preferably hexamethyldisilazane, since the reaction proceeds easily even at low temperatures and it is readily available industrially.

[0052] The amount of the trialkylsilylation agent used is not particularly limited, but in terms of allowing trialkylsilylation to proceed efficiently, it is preferably 1 to 20 parts by mass, more preferably 2 to 15 parts by mass, and even more preferably 3 to 10 parts by mass, relative to 100 parts by mass of polysilsesquioxane.

[0053] The reaction may be carried out in a solvent, such as the solvents used in the synthesis of polysilsesquioxane, which will be described later.

[0054] The reaction temperature for the trialkylsilylation is preferably 30 to 140° C., more preferably 30 to 120° C., and even more preferably 3 to 100° C., in order to suppress the polycondensation reaction of polysilsesquioxane. The reaction time for the trialkylsilylation is not particularly limited, but is preferably 0.5 to 20 hours, more preferably 1 to 10 hours, and even more preferably 2 to 5 hours.

[0055] The method for producing the silylated polysilsesquioxane preferably further comprises a step of synthesizing polysilsesquioxane by subjecting an organosilane compound to a hydrolysis-condensation reaction. The method for producing the silylated polysilsesquioxane preferably comprises a step (1) of synthesizing polysilsesquioxane by subjecting an organosilane compound to a hydrolysis-condensation reaction, and a step (2) of trialkylsilylating the polysilsesquioxane.

[0056] In step (1), the organosilane compound may be a trialkoxysilane compound, a dialkoxysilane compound, etc. In the present invention, the organosilane compound preferably includes a trialkoxysilane compound and / or a dialkoxysilane compound.

[0057] The trialkoxysilane includes, for example, a compound represented by the following general formula (7). R 1 Si(OR 13 )3(7) (In the formula, R 1 is the same as above. R 13 represents an alkyl group, an aryl group, or an acetyl group. 13 may be the same or different.)

[0058] R 13 The alkyl group and aryl group represented by the formula (1) are 1 Preferred examples of the alkyl group and aryl group are the same as those represented by the following formula:

[0059] In the above general formula (7), three (OR 13 ) may be the same or different, but are preferably the same. 13 ) in R 13 is preferably an alkyl group or an acetyl group, and more preferably an alkyl group.

[0060] R 13 The alkyl group represented by the formula (I) preferably has 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms, and even more preferably 1 or 2 carbon atoms.

[0061] Specific examples of the trialkoxysilane compound include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, methyltriisopropoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-butyltrimethoxysilane, n-butyltriethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, isooctyltrimethoxysilane, isooctyltriethoxysilane, and n-decyltrimethoxysilane. Examples of the trialkoxysilane include alkyltrialkoxysilanes such as silane and n-decyltriethoxysilane; aryltrialkoxysilanes such as phenyltrimethoxysilane, phenyltriethoxysilane, parastyryltrimethoxysilane, and parastyryltriethoxysilane; and vinyl skeleton-containing trialkoxysilanes such as vinyltriethoxysilane, vinyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, allyltrimethoxysilane, and allyltriethoxysilane. Among these, alkylalkoxysilanes and aryltrialkoxysilanes are preferred. The trialkoxysilane compounds may be used alone or in combination of two or more.

[0062] The dialkoxysilane compound may be a compound represented by the following general formula (8). R 2 R 3 Si(OR 14 )2(8) (In the formula, R 2 and R 3 is the same as above. R 2 and R 3 may be the same or different. 14 represents an alkyl group, an aryl group, or an acetyl group. 14 may be the same or different.)

[0063] R 14 The alkyl group and aryl group represented by the formula (2) are 2 Preferred examples of the alkyl group and aryl group are the same as those represented by the following formula:

[0064] In the above general formula (8), two (OR 14 ) may be the same or different, but are preferably the same. 14 ) in R 14 is preferably an alkyl group or an acetyl group, and more preferably an alkyl group.

[0065] Above R 14 The alkyl group represented by the following formula preferably has 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms, and even more preferably 1 or 2 carbon atoms.

[0066] Specific examples of the dialkoxysilane compound include dimethyldimethoxysilane, diethyldimethoxysilane, dipropyldimethoxysilane, methylethyldimethoxysilane, methylpropyldimethoxysilane, methylbutyldimethoxysilane, methylpentyldimethoxysilane, methylhexyldimethoxysilane, methylheptyldimethoxysilane, methyloctyldimethoxysilane, methylnonyldimethoxysilane, methyldecyldimethoxysilane, dimethyldiethoxysilane, diethyldiethoxysilane, dipropyldiethoxysilane, methylethyldiethoxysilane, methylpropyldiethoxysilane, methylbutyldiethoxysilane, methylpentyldiethoxysilane, methylhexyldiethoxysilane, methylheptyldiethoxysilane, methyloctyldiethoxysilane, methylnonyldiethoxysilane, methyldecyldiethoxysilane, methylethyldipropoxysilane, methylpropyldipropoxysilane, alkyldialkoxysilanes such as methylphenyldimethoxysilane, methylnaphthyldimethoxysilane, methylbenzyldimethoxysilane, methylphenyldiethoxysilane, methylnaphthyldiethoxysilane, methylbenzyldiethoxysilane, methylphenyldipropoxysilane, methylnaphthyldipropoxysilane, methylbenzyldipropoxysilane; and diaryldialkoxysilanes such as diphenyldimethoxysilane, diphenyldiethoxysilane, and diphenyldipropoxysilane. Among these, dimethyldiethoxysilane is preferred because it is readily available as an industrial product and is easy to synthesize. The dialkoxysilane compounds may be used alone or in combination of two or more.

[0067] The method for subjecting the organosilane compound to hydrolysis and condensation reaction is not particularly limited, and any known method can be used, such as a method of heating the organosilane compound in the presence of water to cause the reaction.

[0068] In the hydrolysis and condensation reaction, the amount of water used is preferably 0.5 to 10.0 mol, more preferably 0.5 to 5.0 mol, and even more preferably 0.5 to 2.0 mol, per mol of alkoxy groups contained in the organosilane compound as a raw material.

[0069] The heating temperature is not particularly limited, but is preferably 40 to 200°C, more preferably 50 to 180°C, and even more preferably 60 to 160°C. The reaction time is not particularly limited, but is preferably 1 to 40 hours, more preferably 2 to 30 hours, and even more preferably 4 to 20 hours.

[0070] The synthesis (hydrolysis and condensation) reaction may be carried out in the air, but is preferably carried out in an inert gas atmosphere such as nitrogen or argon.

[0071] In the above synthesis reaction, commonly used known components such as a catalyst, a solvent, a surfactant, etc. may be further used.

[0072] Examples of the catalyst include phosphorus compounds such as triphenylphosphine, phenylphosphonic acid, 2-ethylhexyl phosphate, and diphenyl phosphate; inorganic acids such as hydrochloric acid, nitric acid, and sulfuric acid; organic acids such as monovalent acids such as formic acid, acetic acid, oxalic acid, citric acid, and propionic acid, and divalent acids such as succinic acid, maleic acid, phthalic acid, and glutaric acid; cyclic acid anhydrides, etc. Only one type of the catalyst may be used, or two or more types may be used.

[0073] The cyclic acid anhydride is a compound that reacts with water to generate an acid by hydrolysis. Preferred examples of the cyclic acid anhydride include compounds having a -CO-O-CO- ring structure, and specific examples include succinic anhydride, maleic anhydride, phthalic anhydride, glutaric anhydride, itaconic anhydride, octenyl succinic anhydride, dodecenyl succinic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, tetrabromophthalic anhydride, 2,4-diethyl glutaric anhydride, himic anhydride (also known as 5-norbornene-2,3-dicarboxylic anhydride), methylnadic anhydride (also known as methyl-5-norbornene-2,3-dicarboxylic anhydride), dodecyl succinic anhydride, chlorendic anhydride, trialkyltetrahydrophthalic anhydride, diphenic anhydride, glycolic anhydride, 1,8-naphthalic anhydride (also known as 1,8-naphthalenedicarboxylic anhydride). Examples of suitable acid anhydrides include acid anhydrides having a cyclic structure, such as succinic anhydride, maleic anhydride, phthalic anhydride, and 2,3-naphthalic anhydride. For example, cyclic acid anhydrides, such as succinic anhydride, maleic anhydride, phthalic anhydride, and glutaric anhydride, react with water and undergo hydrolysis to form diacids, such as succinic acid, maleic acid, phthalic acid, and glutaric acid.

[0074] Among these, cyclic acid anhydrides and / or their hydrolyzates are preferred as catalysts. When the hydrolysis and condensation reaction of organosilane compounds results in low water and alcohol ratios in the reaction system due to dehydration and dealcoholization, the acid used as a catalyst often tends to react with silanol groups in the reaction system and become inactivated when heated. However, when a divalent acid capable of forming a ring, i.e., an acid hydrolyzate of a cyclic acid anhydride, is heated, one side of the acid reacts with a silanol group and bonds, resulting in a ring-closing reaction that detaches it from the silanol group to form a cyclic acid anhydride. The cyclic acid anhydride then bonds with the silanol group through a ring-opening reaction, thereby preventing acid deactivation through a repeated series of ring-closing and ring-opening reactions. Therefore, the use of cyclic acid anhydrides and / or their hydrolyzates as catalysts allows efficient synthesis of polysilsesquioxanes with the addition of a small amount of catalyst.

[0075] The effect of using a cyclic acid anhydride and / or an acid that is a hydrolyzate thereof as a catalyst is not only exhibited in the production of the above-mentioned silylated polysilsesquioxane, but also in a wide range of other production processes for polysilsesquioxanes by the hydrolysis and condensation reaction of organosilane compounds.

[0076] Thus, the present invention also encompasses a method for producing a polysilsesquioxane, which comprises a step of synthesizing a polysilsesquioxane by subjecting an organosilane compound to a hydrolysis-condensation reaction in the presence of a cyclic acid anhydride and / or a hydrolyzate thereof.

[0077] A preferred embodiment of step (1) in the method for producing a silylated polysilsesquioxane of the present invention is also a preferred embodiment of the step of synthesizing a polysilsesquioxane by subjecting an organosilane compound to a hydrolysis-condensation reaction in the presence of a cyclic acid anhydride and / or a hydrolyzate thereof in the method for producing a polysilsesquioxane of the present invention.

[0078] The cyclic acid anhydride and / or its hydrolysate is preferably maleic anhydride and / or maleic acid, since the ring-closing and ring-opening reactions of the catalytic mechanism of the divalent acid capable of forming the ring are easily carried out.

[0079] The amount of the cyclic acid anhydride and / or hydrolyzate thereof used is not particularly limited, but is preferably 0.01 to 5.0 parts by mass, more preferably 0.01 to 1.0 part by mass, and even more preferably 0.01 to 0.5 parts by mass, relative to 100 parts by mass of polysilsesquioxane, in terms of improving reaction efficiency.

[0080] Examples of the solvent include the following solvents, and one or more of these may be used. Water; monoalcohols such as methanol, ethanol, isopropanol, and n-butanol; glycols such as ethylene glycol and propylene glycol; cyclic ethers such as tetrahydrofuran and dioxane; glycol monoethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, and 3-methoxybutanol; glycol ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol ethyl methyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, propylene glycol dimethyl ether, and propylene glycol diethyl ether; ethylene glycol monomethyl ether acetate Glycol monoether esters such as ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, dipropylene glycol monobutyl ether acetate, and 3-methoxybutyl acetate; alkyl esters such as methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, methyl propionate, ethyl propionate, butyl propionate, methyl lactate, ethyl lactate, butyl lactate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, methyl acetoacetate, and ethyl acetoacetate;Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, etc.; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, etc.; aliphatic hydrocarbons such as hexane, cyclohexane, octane, etc.; amides such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc.;

[0081] The polysilsesquioxane synthesized in the polysilsesquioxane synthesis step includes a structural unit (A) represented by the following general formula (1) and a structural unit (B) represented by the following general formula (2). [R 1 SiO 1.5 ] (1) (In formula (1), R 1 represents an alkyl group, an aryl group, or a 3-(meth)acryloxypropyl group. [R 2 R 3 SiO 1.0 ] (2) (In formula (2), R 2 and R 3 are the same or different and represent an alkyl group, an aryl group, or a 3-(meth)acryloxypropyl group.

[0082] Preferred examples of the structural unit (A) and the structural unit (B) contained in the polysilsesquioxane are the same as the structural unit (A) and the structural unit (B) contained in the silylated silsesquioxane described above.

[0083] The structural unit (A) of the polysilsesquioxane is R 1 is an alkyl group having 3 to 10 carbon atoms, and R 1 and a structural unit (a2) in which the structural unit (a1) is an aryl group.

[0084] R in general formula (1) representing the structural unit (A) contained in the polysilsesquioxane 1is an alkyl group having 3 to 10 carbon atoms in the structural unit (a1), the carbon content of the alkyl group is preferably at least 3 mass%, more preferably 3 to 40 mass%, and even more preferably 3 to 20 mass% of the total carbon content of the polysilsesquioxane, in order to improve adhesion to substrates.

[0085] The content of the structural unit (A) in the polysilsesquioxane is preferably 5 to 90 mol %, more preferably 10 to 80 mol %, and even more preferably 15 to 60 mol %, relative to 100 mol % of all structural units in the polysilsesquioxane.

[0086] When the polysilsesquioxane has the structural unit (a1) and the structural unit (a2), the content of the structural unit (a-1) is preferably 1 to 40 mol%, more preferably 3 to 30 mol%, and even more preferably 5 to 15 mol%, relative to 100 mol% of all structural units in the polysilsesquioxane. Furthermore, the content of the structural unit (a-2) is preferably 1 to 60 mol%, more preferably 5 to 40 mol%, and even more preferably 10 to 20 mol%, relative to 100 mol% of all structural units in the polysilsesquioxane.

[0087] The content of the structural unit (B) in the polysilsesquioxane is preferably 10 to 80 mol %, more preferably 20 to 60 mol %, and even more preferably 30 to 50 mol %, relative to 100 mol % of all structural units in the polysilsesquioxane.

[0088] The polysilsesquioxane may further contain structural units similar to the structural units (C) and (D) in the silylated polysilsesquioxane described above.

[0089] The content of the structural unit (C) in the polysilsesquioxane is preferably 0 to 20 mol %, more preferably 0 to 10 mol %, and even more preferably 0 to 5 mol %, relative to 100 mol % of all structural units in the polysilsesquioxane.

[0090] The content of the structural unit (D) in the polysilsesquioxane is preferably 0 to 70 mol %, more preferably 10 to 60 mol %, and even more preferably 20 to 50 mol %, relative to 100 mol % of all structural units in the polysilsesquioxane.

[0091] The polysilsesquioxane obtained in the above step (1) may be subjected to the above-mentioned trialkylsilylation step (2).

[0092] The method for producing the silylated polysilsesquioxane may include other steps in addition to the silylation step and the synthesis step. These other steps include an aging step, a deactivation step, a dilution step, a concentration step, and a purification step, and these steps may be carried out by known methods.

[0093] 3. Silylated Polysilsesquioxane Composition The silylated polysilsesquioxane of the present invention can be used in combination with other components to form a curable composition. Examples of such other components include solvents; colorants (pigments, dyes); dispersants; heat resistance improvers; leveling agents; inorganic fine particles such as silica, titanium, and zirconia fine particles; organic fine particles such as acrylic, polystyrene, and polyolefin fine particles; silane-based, aluminum-based, and titanium-based coupling agents; fillers; resins; plasticizers; polymerization initiators; heat curing agents; polymerization inhibitors; UV absorbers; antioxidants such as hindered phenol-based antioxidants; matting agents; antifoaming agents; antistatic agents; slip agents; surface modifiers; thixotropic agents; polymerizable compounds; and acid generators. These may be used alone or in combination of two or more. These components may be appropriately selected from known components, and the amounts used may be appropriately determined.

[0094] The content of the silylated polysilsesquioxane in the composition may be appropriately set depending on the application and purpose of the composition, and is, for example, 1 to 99 mass%, preferably 10 to 70 mass%, and more preferably 10 to 40 mass%, relative to 100 mass% of the total solid content of the composition.

[0095] The composition preferably contains a hindered phenol-based antioxidant, which acts as a crosslinking agent and allows the elongation and strength of the silylated polysilsesquioxane resin film to be adjusted.

[0096] The hindered phenol-based antioxidant is not particularly limited, and examples thereof include compounds generally known as hindered phenol-based antioxidants. Among these, preferred hindered phenol-based antioxidants include 1,3,5-tris[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 2,2'-dimethyl-2,2'-(2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl)dipropane-1,1'-diyl bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate], pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and 2,4,6-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)mesitylene.

[0097] The content of the hindered phenol-based antioxidant is preferably 0.1 to 10 mass%, more preferably 0.5 to 5 mass%, and even more preferably 1 to 3 mass%, relative to 100 mass% of the total solid content of the composition, in order to improve the strength of the resin film of the silylated polysilsesquioxane.

[0098] The method for preparing the composition is not particularly limited, and the above-mentioned silylated polysilsesquioxane and, if necessary, other components may be mixed and dispersed by a known method.

[0099] 4.Cured product The method for obtaining a cured product using the above composition is not particularly limited, and any known method may be used. For example, a method may be used in which the above composition is applied to a substrate, and the applied product is cured by heating or irradiating with active energy rays such as ultraviolet rays, or by a combination of these to obtain a cured product.

[0100] The material of the base material (substrate) is not particularly limited and may be appropriately selected depending on the purpose and application. For example, it may be an inorganic material, an organic material, a mixture of these, or an organic-inorganic composite.

[0101] The method for applying the composition to form a coating film is not particularly limited, and known methods such as spin coating, gravure coating, dip coating, slot die coating, and spray coating can be used.

[0102] The heating temperature is not particularly limited and may be appropriately selected depending on the composition of the composition, but is usually 100 to 300°C, preferably 100 to 250°C, and more preferably 100 to 200°C.

[0103] The irradiation of active energy rays is not particularly limited as long as it is a method capable of irradiating radiation such as visible light, ultraviolet light, far ultraviolet light, electron beams, and X-rays, and can be carried out by a known method.

[0104] When the cured product is a cured film, the film thickness may be appropriately set depending on the application, but is preferably 1 to 100 μm, more preferably 1 to 50 μm, and more preferably 1 to 20 μm, in terms of low dielectric constant and good flexibility.

[0105] 5.Applications The silylated polysilsesquioxane of the present invention and compositions containing the same can provide cured products with low dielectric properties. Therefore, the silylated polysilsesquioxane and compositions containing the same can be suitably used in applications requiring a low dielectric constant. Furthermore, the silylated polysilsesquioxane can provide cured products with high elongation and excellent flexibility. Therefore, the silylated polysilsesquioxane can be suitably used in applications requiring flexibility. Examples of such applications include optical materials (members), machine component materials, electrical and electronic component materials, automotive component materials, civil engineering and construction materials, molding materials, as well as various applications such as paints and adhesives. Among these, the silylated polysilsesquioxane is preferably used in optical materials or low-dielectric materials. Optical materials and low-dielectric materials containing the silylated polysilsesquioxane also constitute the present invention.

[0106] Specific examples of uses of the silylated polysilsesquioxane of the present invention and compositions containing the same include optical applications such as transparent glass and cover glass, such as camera imaging lenses, LED encapsulants, optical adhesives, optical transmission bonding materials, filters, diffraction gratings, prisms, light guides, watch glasses, and cover glass for display devices; optical device applications such as photosensors, photoswitches, LEDs, light-emitting elements, optical waveguides, multiplexers, demultiplexers, disconnectors, optical splitters, and optical fiber adhesives; display device applications such as substrates for display elements such as LCDs, organic ELs, and PDPs, substrates for color filters, substrates for touch panels, display protective films, display backlights, light guide plates, antireflection films, and antifogging films; and insulating films. Among these, the silylated polysilsesquioxane of the present invention is preferably used to form insulating films that insulate metal wiring, other metal wiring, conductive members, and the like, on substrates such as silicon in electric and electronic devices.

[0107] As described above, the silylated polysilsesquioxane of the present invention can give a cured product having a low dielectric constant and excellent flexibility. [Example]

[0108] Examples are given below to explain the present invention in more detail, but the present invention is not limited to only these examples.

[0109] In the present invention, each evaluation was performed by the following method. <Weight-average molecular weight> Using polystyrene as a standard substance and tetrahydrofuran as an eluent, the weight-average molecular weight was measured by GPC (gel permeation chromatography) method using HLC-8320GPC (manufactured by Tosoh Corporation), column: TSKgel SuperHZ-N (manufactured by Tosoh Corporation).

[0110] <Solid content> About 1 g of the resin solution was weighed into an aluminum cup, about 3 g of acetone was added and dissolved, and then it was naturally dried at room temperature. Then, using a vacuum dryer (manufactured by Tokyo Rika Kikai Co., Ltd., product name: VOS-301SD type), it was dried at 200 °C for 1 hour under vacuum, cooled in a desiccator, and the mass was measured. From the mass reduction amount, the solid content (mass%) of the polymer solution was calculated.

[0111] <T-structure> About 0.3 g of the resin solution was weighed into a screw tube, about 0.8 g of heavy dimethyl sulfoxide was added and dissolved, and then it was charged into an NMR tube. 29 Measured by Si-NMR (manufactured by JEOL Ltd., JNM-ECZ600). The amount (mol%) of the T-structure [R 1 SiO 1.5 is the T-structure [R 1 SiO 1.5 , D-structure [R 1 XSiO 1.0 and [R 2 R 3 SiO 1.0 , M-structure [R 1 X2SiO 0.5 and [R 2 R 3 YSiO 0.5The area of ​​each peak of the monomer and the monomer was determined, and the ratio of the area of ​​the T-isomer structure to the total area was calculated. That is, in the case of polysilsesquioxane obtained by hydrolysis and condensation reaction of phenyltrimethoxysilane, n-propyltrimethoxysilane, and dimethyldiethoxysilane, the homopolymer obtained by hydrolysis and condensation reaction of phenyltrimethoxysilane, the homopolymer obtained by hydrolysis and condensation reaction of n-propyltrimethoxysilane, the homopolymer obtained by hydrolysis and condensation reaction of dimethyldiethoxysilane, and the samples of phenyltrimethoxysilane, n-propyltrimethoxysilane, and dimethyldiethoxysilane were 29 Si-NMR analysis was performed. The T-isomer of phenyltrimethoxysilane exhibited peaks at -76 to -81 ppm, the D-isomer at -67 to -72 ppm, the M-isomer at -60 to -63 ppm, and the monomer at -55 ppm. The T-isomer of n-propyltrimethoxysilane exhibited peaks at -63 to -69 ppm, the D-isomer at -53 to -61 ppm, the M-isomer at -47 to -49 ppm, and the monomer at -42 ppm. The D-isomer of dimethyldiethoxysilane exhibited peaks at -16 to -22 ppm, the M-isomer at -11 to -14 ppm, and the monomer at -5 ppm. The area of ​​each peak was calculated, and the amount of T-isomer (mol%) was calculated from the ratio of the area of ​​the T-isomer to the total area. The peaks of the T-structure, D-structure, M-structure and monomer of other polysilsesquioxanes were similarly identified, and the area of ​​each peak was calculated to determine the amount of the T-structure.

[0112] <Trialkylsilylation rate> The trialkylsilylation rate in the silylated polysilsesquioxane was calculated based on the total 100 mol% of the trialkylsilyl groups and the functional groups (alkoxy groups, halogen atoms, hydrogen atoms, or hydroxyl groups) bonded to the silicon atoms. Approximately 0.3 g of the silylated polysilsesquioxane resin solution was weighed into a screw tube, and approximately 0.8 g of deuterated dimethyl sulfoxide was added to dissolve the solution. The solution was then placed in an NMR tube and analyzed by 29Si-NMR (JNM-ECZ600, manufactured by JEOL Ltd.). (i) The T-isomer structure [R1 SiO1.5], (ii):D structure [R 1 XSiO 1.0 ], (iii):D-structure [R 2 R 3 SiO 1.0 ], (iv):M-body structure [R 1 X2SiO 0.5 ], (v):M-body structure [R 2 R 3 YSiO 0.5 ], (vi): A trialkylsilyl group [R 4 R 5 R 6 SiO 0.5 The area of ​​each of the structures to which [] was bonded was determined, and the trialkylsilylation rate was calculated using the following formulas A and B. Equation A: Amount of functional groups in polysilsesquioxane (mol%) = 1 - ((i) + (ii) × 2 / 3 + (iii) + (iv) × 1 / 3 + (v) × 1 / 2) Formula B: Trialkylsilylation rate (%) = (vi) / ((vi) + (value of Formula A)) Specifically, in the polysilsesquioxane obtained by the hydrolysis and condensation reaction of phenyltrimethoxysilane, n-propyltrimethoxysilane, and dimethyldiethoxysilane, as described in the calculation method for the T-isomer structure above, when the silanol groups bonded to the polysilsesquioxane were methylsilylated with hexamethyldisilazane, a methylsilylation peak was observed at 8 ppm. The area ratio of each peak was determined, and the methylsilylation rate was calculated using the above formulas A and B. For other silylated polysilsesquioxanes, the trimethylsilylation rate relative to the silanol groups bonded to silicon in the polysilsesquioxane was similarly calculated using the above formulas A and B.

[0113] <Stretch> The resin solution was transferred to a Teflon (registered trademark) Petri dish and dried at 250°C for 1 hour using a hot air dryer to obtain a resin film approximately 100 μm thick. The resin film was then punched into a dumbbell shape so that the area to be tested for tensile strength was 1 cm wide and 3 cm long. The punched specimen was used as a sample. The specimen was stretched at 5 mm / min using an autograph (Shimadzu Corporation, AG-X Plus), and the length at break was measured, and the elongation (%) was calculated using the following formula: Elongation (%) = {(length at break (cm) - 3 cm) / 3 cm} x 100

[0114] <Dielectric constant, dielectric loss tangent> The resin solution was transferred to a Teflon (registered trademark) Petri dish and dried at 300°C for 1 hour using a hot air dryer to obtain a resin film approximately 100 μm thick. The resin film was then cut to a width of 2 mm and a length of 9 cm to prepare a sample. After placing the sample in the cavity resonator, the dielectric constant and dielectric loss tangent were measured using the cavity resonator perturbation method at a temperature of 20°C, humidity of 45%, and a frequency of 1 GHz using a network analyzer MS46122B (manufactured by Anritsu Corporation) and a cavity resonator CABLE 1 GHz TM mode (manufactured by AET Corporation).

[0115] <5% thermal weight reduction> Approximately 30 mg of the resin solution was weighed into an aluminum pan, and using a TGA-50 / 50H (Shimadzu Corporation), the temperature was raised from room temperature to 200°C at 20°C / min under a nitrogen atmosphere, held at 200°C for 1 hour, and then raised to 500°C at 10°C / min, and the temperature at which the weight lost 5% from 200°C to 500°C was read.

[0116] (Synthesis Example 1) A reaction vessel was charged with 20.1 parts of diethylene glycol dimethyl ether, 216 parts of phenyltrimethoxysilane, 35.79 parts of n-propyltrimethoxysilane, and 129.22 parts of dimethyldiethoxysilane. The atmosphere was replaced with nitrogen, and while stirring, 102.07 parts of water and 0.76 parts of 2-ethylhexyl phosphate (mono- and diester mixture, manufactured by Tokyo Chemical Industry Co., Ltd.) were added and the temperature was raised to 80 ° C. The temperature was then raised from 80 ° C to 160 ° C at a rate of 10 ° C / hour while distilling off water and by-product alcohol. After reaching 160 ° C, the reaction was carried out at 160 ° C for 6 hours, and then 201.95 parts of diethylene glycol dimethyl ether was added to obtain a resin solution. The physical properties of the resulting resin solution are shown in Table 1.

[0117] (Synthesis Example 2) Resin solution 1 was obtained in the same manner as in Synthesis Example 1. 6.84 parts of hexamethyldisilazane was added and mixed to the obtained resin solution, and the mixture was reacted at 100°C for 4 hours to obtain a resin solution. The physical properties of the obtained resin solution 2 are shown in Table 1.

[0118] (Synthesis Examples 3 to 6) Resin solutions were obtained in the same manner as in Synthesis Example 2, except that the type of trialkoxysilane compound and the type of synthesis catalyst used were changed and the charged composition was changed as shown in Table 1. The physical properties of the obtained resin solutions are shown in Table 1.

[0119] (Synthesis Example 7) A reaction vessel was charged with 400 parts of dimethyldiethoxysilane, and the atmosphere was replaced with nitrogen. While stirring, 97.22 parts of water and 2.0 parts of 2-ethylhexyl phosphate (mono- and diester mixture, manufactured by Tokyo Chemical Industry Co., Ltd.) were added, and the temperature was raised to 80°C. The temperature was then raised from 80°C to 160°C at a rate of 10°C / hour while distilling off water and by-product alcohol. After reaching 160°C, the reaction was carried out at 160°C for 6 hours, yielding a resin solution.

[0120] The resin solutions obtained in Synthesis Examples 1 to 7 were evaluated for elongation, dielectric constant, dielectric loss tangent, and 5% thermal weight loss by the above-mentioned methods. The results are shown in Table 2.

[0121] [Table 1]

[0122] [Table 2]

[0123] Tables 1 and 2 show that silylated polysilsesquioxane has a lower dielectric constant, greater elongation, and superior flexibility compared to non-silylated polysilsesquioxane. Furthermore, silylated polysilsesquioxane also has superior heat resistance.

Claims

1. A polymerizable compound including a structural unit (A) represented by the following general formula (1) and a structural unit (B) represented by the following general formula (2), and having at least one trialkylsilyl group: A silylated polysilsesquioxane characterized by: [R １ SiO １．５ ] (1) (In formula (1), R １ represents an alkyl group, an aryl group, or a 3-(meth)acryloxypropyl group. [R ２ R ３ SiO １．０ ] (2) (In formula (2), R ２ and R ３ are the same or different and represent an alkyl group, an aryl group, or a 3-(meth)acryloxypropyl group.

2. 2. The silylated polysilsesquioxane according to claim 1, wherein the content of trialkylsilyl groups in the silylated polysilsesquioxane is 10 mol % or more, relative to 100 mol % in total of the trialkylsilyl groups and the hydroxyl groups bonded to silicon atoms.

3. The structural unit (A) is R １ is an alkyl group having 3 to 10 carbon atoms, and R １ and a structural unit (a2) in which R is an aryl group.

4. The silylated polysilsesquioxane is a trialkylsilylated product of polysilsesquioxane, The silylated polysilsesquioxane according to claim 3, characterized in that the polysilsesquioxane has a carbon content of the alkyl group of the structural unit (a1) of 3% by mass or more relative to 100% by mass of the total carbon content of the polysilsesquioxane.

5. 2. The silylated polysilsesquioxane according to claim 1, wherein the content of the structural unit (A) is 10 mol % or more relative to 100 mol % of all structural units of the silylated polysilsesquioxane.

6. An optical material comprising the silylated polysilsesquioxane according to claim 1.

7. A low dielectric material comprising the silylated polysilsesquioxane of claim 1.

8. A method for producing a silylated polysilsesquioxane, comprising: a step of trialkylsilylating polysilsesquioxane, The polysilsesquioxane contains a structural unit (A) represented by the following general formula (1) and a structural unit (B) represented by the following general formula (2): A method for producing a silylated polysilsesquioxane, comprising: [R １ SiO １．５ ] (1) (In formula (1), R １ represents an alkyl group, an aryl group, or a 3-(meth)acryloxypropyl group. [R ２ R ３ SiO １．０ ] (2) (In formula (2), R ２ and R ３ are the same or different and represent an alkyl group, an aryl group, or a 3-(meth)acryloxypropyl group.

9. the trialkylsilylation step is carried out by reacting the polysilsesquioxane with a trialkylsilylation agent, 9. The method for producing a silylated polysilsesquioxane according to claim 8, wherein the trialkylsilylating agent is a compound represented by the following general formula (6): R ７ R ８ R ９ Si-X (6) (In formula (6), R ７ , R ８ and R ９ are the same or different and represent an alkyl group, and X represents a hydrogen atom, a chlorine atom, an alkoxy group, a hydroxyl group, or —NH—SiR １０ R １１ R １２ Represents R １０ , R １１ and R １２ are the same or different and represent an alkyl group.

10. The method for producing a silylated polysilsesquioxane according to claim 9, wherein the trialkylsilylating agent is hexamethyldisilazane.

11. 9. The method for producing a silylated polysilsesquioxane according to claim 8, further comprising a step of synthesizing a polysilsesquioxane by subjecting an organosilane compound to a hydrolysis-condensation reaction.

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