Polysiloxane composition and use thereof

Abstract

Provided is a polysiloxane composition from which a coating film having a low refractive index can be formed and which has excellent storage stability and applicability to a base material. The composition is represented by an average unit formula of [R1(CH3)2SiO1 / 2]a[R1(CH3)SiO2 / 2]b[R1SiO3 / 2]c[SiO4 / 2]d[R2O1 / 2]e, and contains 10-90 parts by mass of a branched polysiloxane having a refractive index of less than 1.45 at a wavelength of 633 nm and 90-10 parts by mass of an organic solvent other than benzene, toluene, ethylbenzene, and xylene. In addition, in the formula, R1 is a hydrogen atom, a C1-C6 monovalent aliphatic hydrocarbon group, or a C6-C12 monovalent aromatic hydrocarbon group, R2 is a hydrogen atom or a C1-C4 monovalent hydrocarbon group, and a, b, c, d, and e satisfy the following conditions of: 0<a≤0.4; 0≤b≤0.5; 0.4≤c<1; 0≤d≤0.6; 0.03≤e≤0.3; and a+b+c+d=1.

Description

Polysiloxane composition and its uses

[0001] The present invention relates to a polysiloxane composition and its use.

[0002] Polysiloxanes have high heat resistance and excellent chemical stability, and are therefore used as coating agents, potting agents, insulating materials, etc. for electronic and electrical devices.

[0003] Low-refractive index materials are used in various display devices, such as those for mobile devices, industrial equipment, and car navigation systems, for purposes such as anti-reflection and protection of various functional components. Fluorinated polymer materials are well-known as representative low-refractive index materials. However, recent research has revealed that fluorinated polymer materials are persistently biodegradable, highly bioaccumulative, and have concerns about their safety for living organisms. Therefore, there is a global movement to restrict fluorinated polymer materials. Polysiloxane-containing coating materials are attracting attention as alternative materials.

[0004] Polysiloxanes are generally easily soluble in TX solvents such as toluene and xylene, and therefore polysiloxane compositions containing polysiloxane and TX solvents are sometimes used as coating materials. On the other hand, from the viewpoint of reducing the burden on the environment, techniques have been proposed for preparing polysiloxane compositions using organic solvents other than TX solvents (see, for example, Patent Documents 1 to 3).

[0005] JP 2021-172706 A JP 2021-172707 A International Publication No. 2020 / 036074

[0006] However, although the above-mentioned conventional polysiloxane compositions are capable of forming coating films that require a low refractive index, they have problems such as excessive viscosity increase when stored for a long period of time and uneven coating when applied to a substrate such as a silicon wafer. In other words, the above-mentioned conventional polysiloxane compositions have room for improvement in terms of forming coating films with a low refractive index while exhibiting excellent storage stability and coatability to substrates.

[0007] Therefore, an object of the present invention is to provide a polysiloxane composition that can form a coating film with a low refractive index and that has excellent storage stability and applicability to substrates, as well as uses thereof.

[0008] The present inventors have conducted extensive research to achieve the above object, and have newly discovered that a polysiloxane composition containing a branched polysiloxane having a specified composition and properties and a specified organic solvent has excellent storage stability and coatability onto a substrate, and further, that the polysiloxane composition can be used to form a coating film with a low refractive index, thereby completing the present invention.

[0009] That is, according to the present invention, there are provided polysiloxane compositions [1] to [8], an insulating coating agent [9], an insulating coating

[10] , a method for producing an insulating coating

[11] , and a display device

[12] , all of which are described below.

[0010] [1] (A) The following average unit formula (1): [R 1 (CH3)2SiO 1 / 2 ] ａ [R 1 (CH3)SiO 2 / 2 ] b [R 1 SiO 3 / 2 ] c [SiO 4 / 2 ] d [R 2 O 1 / 2 ] e ...(1) (In formula (1), R １ are each independently a hydrogen atom, a monovalent aliphatic hydrocarbon group having from 1 to 6 carbon atoms, or a monovalent aromatic hydrocarbon group having from 6 to 12 carbon atoms; R ２a, b, c, d, and e are numbers that satisfy the following conditions: 0<a≦0.4; 0≦b≦0.5; 0.4≦c<1; 0≦d≦0.6; 0.03≦e≦0.3; a+b+c+d=1.) and have a refractive index of less than 1.45 at a wavelength of 633 nm; and (B) 90 to 10 parts by mass of an organic solvent other than benzene, toluene, ethylbenzene, and xylene.

[0011] [2] R in the average unit formula (1) ２ The polysiloxane composition according to [1] above, wherein contains a hydrogen atom.

[0012] [3] R in the average unit formula (1) １ The polysiloxane composition according to [1] or [2] above, wherein the methyl group is contained and the monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms is not contained.

[0013] [4] R in the average unit formula (1) １ are each independently a methyl group or an n-propyl group.

[0014] [5] The polysiloxane composition according to any one of [1] to [4] above, wherein b and d in the average unit formula (1) are 0.

[0015] [6] The polysiloxane composition according to any one of [1] to [5] above, wherein component (B) comprises at least one selected from the group consisting of propylene glycol alkyl ether compounds, alkylcycloalkane compounds, and alcohols having 4 to 7 carbon atoms.

[0016] [7] The polysiloxane composition according to any one of [1] to [5] above, wherein component (B) comprises at least one selected from propylene glycol methyl ether, propylene glycol methyl ether acetate, methylcyclohexane, and ethylcyclohexane.

[0017] [8] The polysiloxane composition according to any one of [1] to [5] above, wherein component (B) contains methylcyclohexane.

[0018] [9] An insulating coating agent comprising the polysiloxane composition according to any one of [1] to [8] above.

[0019]

[10] An insulating coating formed using the polysiloxane composition according to any one of [1] to [8] above.

[0020]

[11] A method for producing an insulating coating, comprising a step of removing the component (B) from the polysiloxane composition according to any one of [1] to [8] above.

[0021]

[12] A display device comprising a layer made of a solid material formed using the polysiloxane composition according to any one of [1] to [8] above. The display device may be, for example, a liquid crystal display, an organic electroluminescence display, or an organic electroluminescence flexible display.

[0022] According to the present invention, it is possible to provide a polysiloxane composition that is capable of forming a coating film with a low refractive index and that has excellent storage stability and applicability to substrates, as well as uses thereof.

[0023] Hereinafter, embodiments of the present invention will be described in detail. The upper and lower limit values ​​of the numerical ranges described in this specification can be arbitrarily combined. For example, when a numerical range is described as "preferably 30 to 100, more preferably 40 to 80," the ranges "30 to 80" and "40 to 100" are also included in the numerical ranges described in this specification. Furthermore, when a numerical range is described as "preferably 30 or more, more preferably 40 or more, and preferably 100 or less, more preferably 80 or less," the ranges "30 to 80" and "40 to 100" are also included in the numerical ranges described in this specification. Additionally, when a numerical range described in this specification, for example, "60 to 100," means a range of "60 or more and 100 or less."

[0024] (Polysiloxane Composition) The polysiloxane composition of the present invention comprises, as essential components, a branched polysiloxane, which is component (A), and an organic solvent, which is component (B). The amount of component (A) contained in the polysiloxane composition of the present invention is 10 to 90 parts by mass, where the total mass of components (A) and (B) is 100 parts by mass. In addition, the amount of component (B) contained in the polysiloxane composition of the present invention is 10 to 90 parts by mass, where the total mass of components (A) and (B) is 100 parts by mass. The polysiloxane composition of the present invention may optionally contain other components in addition to components (A) and (B).

[0025] <Component (A): Branched Polysiloxane> The branched polysiloxane that is component (A) must have a predetermined composition and a refractive index of less than 1.45 at a wavelength of 633 nm.

[0026] <<Composition of Component (A)>> Component (A) of the present invention is represented by the following average unit formula (1): [R 1 (CH3)2SiO 1 / 2 ] ａ [R 1 (CH3)SiO 2 / 2 ] b [R 1 SiO 3 / 2 ] c [SiO 4 / 2 ] d [R 2 O 1 / 2 ] e ...(1)

[0027] In the above formula (1), R １ are each independently a hydrogen atom, a monovalent aliphatic hydrocarbon group having from 1 to 6 carbon atoms, or a monovalent aromatic hydrocarbon group having from 6 to 12 carbon atoms; R ２ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 4 carbon atoms, and a, b, c, d, and e are numbers that satisfy the following conditions: 0<a≦0.4; 0≦b≦0.5; 0.4≦c<1; 0≦d≦0.6; 0.03≦e≦0.3; a+b+c+d=1. In this specification, the composition of the branched polysiloxane is １３ C-NMR spectroscopy and ２９The identification can be performed by nuclear magnetic resonance spectroscopy such as Si-NMR spectroscopy.

[0028] The trifunctional siloxane unit "R １ (CH ３ ) ２ SiO １／２ "R" １ may be one type or two or more types. That is, the branched polysiloxane of component (A) may contain only one type of trifunctional siloxane unit, or may contain two or more types. １ (CH ３ ) SiO ２／２ "R" １ may be one type or two or more types. That is, the branched polysiloxane of component (A) may contain only one type of difunctional siloxane unit, or may contain two or more types. １ SiO ３／２ "R" １ may be one type or two or more types. That is, the branched polysiloxane of component (A) may contain only one type of monofunctional siloxane unit, or may contain two or more types. ２ O １／２ (hereinafter, sometimes referred to as "OZ group") ２ In other words, the branched polysiloxane of component (A) may contain only one type of reactive group, or may contain two or more types.

[0029] In the above formula (1), R １ As described above, R is a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms. １The monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms constituting R is not particularly limited, but examples thereof include linear or branched saturated aliphatic hydrocarbon groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, sec-butyl, pentyl, and hexyl groups; cyclic saturated aliphatic hydrocarbon groups such as cyclopentyl and cyclohexyl groups; and alkenyl groups such as vinyl, allyl, butenyl, and hexenyl groups. １ The monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms constituting the formula (I) is not particularly limited, but examples thereof include aryl groups such as a phenyl group and a naphthyl group; and arylalkyl groups such as a benzyl group and a phenylethyl group.

[0030] In one embodiment of the present invention, R １ In consideration of the refractive index of component (A), R preferably contains at least one of a linear aliphatic saturated hydrocarbon group and an alkenyl group, more preferably contains at least one selected from the group consisting of a methyl group, a vinyl group, and an n-propyl group, preferably contains at least one of a methyl group and an n-propyl group, and even more preferably contains a methyl group. １ In consideration of the refractive index of component (A), it is preferable that R in the above formula (1) does not contain a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms. １ In consideration of the refractive index of component (A), it is preferable that all of the groups be at least one of methyl groups and n-propyl groups, and it is more preferable that all of the groups be methyl groups.

[0031] In the above formula (1), R ２ As described above, R is a hydrogen atom or a monovalent hydrocarbon group having 1 to 4 carbon atoms. ２ The monovalent hydrocarbon group having 1 to 4 carbon atoms constituting the formula (I) is not particularly limited, but examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, and a sec-butyl group.

[0032] In one embodiment of the present invention, R２ R in the above formula (1) preferably contains at least one selected from the group consisting of a hydrogen atom, a methyl group, and an ethyl group, more preferably contains at least one of a hydrogen atom and a methyl group, and further preferably contains a hydrogen atom. ２ When is a hydrogen atom, the applicability of the polysiloxane composition to a substrate is further improved.

[0033] In the above formula (1), the trifunctional siloxane unit "R １ (CH ３ ) ２ SiO １／２ " satisfies 0<a≦0.4 (in other words, more than 0 and 0.4 or less). That is, the trifunctional siloxane unit is an essential unit in the branched polysiloxane. In one aspect of the present invention, the ratio a is preferably 0.05 or more, more preferably 0.09 or more, and preferably 0.3 or less, more preferably 0.25 or less, and even more preferably 0.2 or less. When the ratio a is greater than 0, that is, when the branched polysiloxane contains a trifunctional siloxane unit, it becomes easy to control the molecular weight of the branched polysiloxane. On the other hand, when the ratio a is 0.4 or less, it is possible to suppress a decrease in the softening point and strength (coating film strength) of a coating film formed using the branched polysiloxane composition.

[0034] In the above formula (1), the bifunctional siloxane unit "R １ (CH ３ ) SiO ２／２" satisfies 0≦b≦0.5 (in other words, 0 or more and 0.5 or less). That is, the bifunctional siloxane unit does not have to be contained in the branched polysiloxane. In one aspect of the present invention, the ratio b is preferably 0.3 or less, more preferably 0.2 or less, even more preferably 0.1 or less, and particularly preferably 0 (in other words, the branched polysiloxane does not contain a bifunctional siloxane unit). When the ratio b is 0.5 or less, it is possible to suppress a decrease in the softening point and strength (coating strength) of a coating film formed using the polysiloxane composition. As described above, in one aspect of the present invention, the branched polysiloxane does not have to contain a bifunctional siloxane unit. On the other hand, when the branched polysiloxane contains a bifunctional siloxane unit, there is an advantage in that it can impart flexibility to a coating film formed using the polysiloxane composition.

[0035] In the above formula (1), the monofunctional siloxane unit "R １ SiO ３／２ " satisfies 0.4≦c<1 (in other words, 0.4 or more and less than 1). That is, the monofunctional siloxane unit is the main structural unit of the branched polysiloxane. In one aspect of the present invention, the ratio c is preferably 0.5 or more, more preferably 0.6 or more, and even more preferably 0.7 or more. When the ratio c is 0.4 or more, the softening point of the coating film formed using the polysiloxane composition can be increased. In one aspect of the present invention, the ratio c can be 0.95 or less, or 0.92 or less.

[0036] In the above formula (1), the non-functional siloxane unit "SiO ４／２" satisfies 0≦d≦0.6 (in other words, 0 or more and 0.6 or less). That is, like the difunctional siloxane units, nonfunctional siloxane units do not need to be contained in the branched polysiloxane. In one aspect of the present invention, the ratio d is preferably 0.4 or less, more preferably 0.2 or less, even more preferably 0.1 or less, and particularly preferably 0 (in other words, the branched polysiloxane does not contain nonfunctional siloxane units). When the ratio d is 0.6 or less, the brittleness of the coating film formed using the polysiloxane composition can be reduced. As described above, in one aspect of the present invention, the branched polysiloxane does not need to contain nonfunctional siloxane units. On the other hand, when the branched polysiloxane contains nonfunctional siloxane units, there is an advantage in that the softening point of the coating film formed using the polysiloxane composition can be increased.

[0037] In the above formula (1), the sum of the ratios a, b, c, and d satisfies a+b+c+d=1.

[0038] In the above formula (1), the remaining reactive group "R ２ O ２／１ The ratio e in " satisfies 0.03≦e≦0.3 (in other words, 0.03 or more and 0.3 or less). When the ratio e is 0.03 or more, the coatability to the substrate can be improved, and when it is 0.3 or less, the storage stability of the polysiloxane composition and the coatability to the substrate can be improved. In one aspect of the present invention, the ratio e is preferably 0.2 or less, and more preferably 0.15 or less.

[0039] In one embodiment of the present invention, from the viewpoint of further improving the storage stability and coatability onto a substrate of the polysiloxane composition, the content of silanol groups (Si—OH) per mole of silicon atoms in the branched polysiloxane of component (A) is preferably 0.03 mol or more, preferably 0.2 mol or less, and more preferably 0.15 mol or less.

[0040] <<Properties>> The branched polysiloxane of component (A) has a refractive index of less than 1.45 at a wavelength of 633 nm. This refractive index is preferably 1.44 or less, more preferably 1.43 or less, and even more preferably 1.42 or less. This characteristic allows the solid obtained from the polysiloxane composition of the present invention to be widely used in a variety of applications requiring a low refractive index material. The refractive index of component (A) can be controlled by the type of substituent on the silicon atom in the branched polysiloxane described above, as well as the ratio of various siloxane units and OZ groups. For example, the refractive index of component (A) can be lowered by decreasing the ratio of monofunctional siloxane units and increasing the ratio of trifunctional siloxane units. In this specification, the "refractive index at a wavelength of 633 nm" of the branched polysiloxane of component (A) refers to the refractive index at a wavelength of 633 nm measured in the state of a coating film prepared by the method described in the Examples below.

[0041] The weight-average molecular weight of the branched polysiloxane, component (A), is not particularly limited. In one embodiment of the present invention, the weight-average molecular weight of component (A) is preferably 1,000 or more, more preferably 1,500 or more, even more preferably 2,000 or more, particularly preferably 2,500 or more, and is preferably 200,000 or less, more preferably 150,000 or less. If the weight-average molecular weight of component (A) is within the above-mentioned range, the coatability of the polysiloxane composition to a substrate can be further improved. In this specification, the "weight-average molecular weight" and the "number-average molecular weight" described below each refer to the molecular weight measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

[0042] The polydispersity index (hereinafter sometimes referred to as "PDI") of the branched polysiloxane, component (A), is not particularly limited. In one embodiment of the present invention, the polydispersity index of component (A) may be, for example, 1.5 or more and 30 or less. The higher the weight average molecular weight described above, the larger the PDI value tends to be. Note that PDI is defined as the value of "Mw / Mn" using the number average molecular weight (Mn) and the weight average molecular weight (Mw).

[0043] There are no particular restrictions on the softening point and glass transition temperature of the branched polysiloxane of component (A). In one embodiment of the present invention, the glass transition temperature of component (A) is preferably 30°C or higher. If the glass transition temperature of component (A) is 30°C or higher, the tackiness (adhesiveness) of the coating film surface can be reduced when the polysiloxane composition is applied to a substrate to form a coating film. In addition to reducing tackiness, taking into consideration the usage environment of electronic and electrical devices, particularly display devices, in which a coating film of the polysiloxane composition is used, the glass transition temperature is more preferably 60°C or higher, and even more preferably 100°C or higher. In this specification, the "glass transition temperature" of component (A) can be determined by a measurement method using a differential scanning calorimeter.

[0044] <<Method for Preparing Component (A)>> There are no particular limitations on the method for preparing the branched polysiloxane serving as component (A). Component (A) can be prepared using, for example, the following methods 1), 2), or 3). 1) A method in which a mixture containing starting materials including a plurality of alkoxysilanes and / or linear siloxanes, a reaction solvent, and an acidic catalyst is heated to carry out a hydrolysis and condensation reaction, thereby preparing a branched polysiloxane solution. 2) A method in which a mixture containing the same starting materials, reaction solvent, and basic catalyst as in method 1) is heated to carry out a hydrolysis and condensation reaction, thereby preparing a branched polysiloxane solution. 3) A method in which a mixture containing the same starting materials, reaction solvent, and acidic catalyst as in method 1) is heated to carry out a hydrolysis and condensation reaction, and then a basic catalyst is added to the resulting reaction solution to further react, thereby preparing a branched polysiloxane. In the above methods 1) to 3), operations such as removal of by-product alcohol and excess water, neutralization, and / or filtration may be performed at any time, as needed.

[0045] Among the above-mentioned methods 1) to 3), methods 1) and 3) are preferably applicable. Furthermore, since heavy metals such as platinum atoms are not contained in the products obtained by any of the above-mentioned methods 1) to 3), these methods are advantageous when applied to electronic materials, particularly electronic materials in the semiconductor field.

[0046] The above-mentioned method 3) will be further explained with a specific example. First, the starting materials, methyltrimethoxysilane and hexamethyldisiloxane, are dissolved in methylcyclohexane as a reaction solvent, and aqueous hydrochloric acid is added as an acidic catalyst to obtain a mixture. This mixture is heated to carry out a hydrolysis and condensation reaction, yielding a reaction solution containing a reactive branched polysiloxane with a low degree of condensation. A basic catalyst, aqueous potassium hydroxide, is added to this reaction solution to make the reaction system basic. After that, the by-product methyl alcohol and excess water are removed, and further neutralization and filtration steps are performed to obtain a methylcyclohexane solution of a highly condensed poly(trimethylsiloxane / methylsiloxane) copolymer as component (A). If necessary, it is also possible to change the dispersion solvent for component (A) by adding a desired solvent and performing a solvent substitution operation. For example, a 4-methyl-2-propanol solution of component (A) can be prepared by adding 4-methyl-2-propanol to a solution of component (A) and removing the methylcyclohexane under atmospheric or reduced pressure. The structure and molecular weight of the resulting component (A) can be controlled by the ratio of alkoxysilanes and / or linear siloxanes during the reaction, the type and amount of reaction solvent, the amount of water used, and the amount of basic catalyst.

[0047] <<Content of Component (A)>> As described above, the amount of component (A) contained in the polysiloxane composition of the present invention must be 10 parts by mass or more and 90 parts by mass or less, where the total mass of component (A) and component (B) is 100 parts by mass. When the amount of component (A) per 100 parts by mass of the total of component (A) and component (B) is within the above-mentioned range, the storage stability and coatability of the polysiloxane composition to a substrate can be ensured. Furthermore, it becomes easier to control the film thickness of a coating film formed from the polysiloxane composition. In one aspect of the present invention, from the viewpoint of further improving the storage stability and coatability of the polysiloxane composition to a substrate, the amount of component (A) contained in the polysiloxane composition of the present invention is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, and preferably 80 parts by mass or less, more preferably 70 parts by mass or less, even more preferably 60 parts by mass or less, and particularly preferably 50 parts by mass or less, where the total mass of component (A) and component (B) is 100 parts by mass.

[0048] In one embodiment of the present invention, from the viewpoint of further improving the storage stability and coatability of the polysiloxane composition to a substrate, the amount of component (A) contained in the polysiloxane composition of the present invention is preferably 20% by mass or more, more preferably 30% by mass or more, and is preferably 80% by mass or less, more preferably 70% by mass or less, even more preferably 60% by mass or less, and particularly preferably 50% by mass or less, based on the total mass of the polysiloxane composition being 100% by mass.

[0049] <Component (B): Organic Solvent Other Than Benzene, Toluene, Ethylbenzene, and Xylene> Component (B) of the present invention is an organic solvent other than benzene, toluene, ethylbenzene, and xylene. Component (B) has the function of controlling the coatability of component (A) and adjusting the thickness of the coating film. Furthermore, component (B) has the advantage of posing less concern for biological safety compared to benzene, toluene, ethylbenzene, and xylene.

[0050] <<Types of Component (B)>> The organic solvent usable as component (B) is not particularly limited, and examples thereof include (poly)alkylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, diethylene glycol mono-n-butyl ether, propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-n-butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, and dipropylene glycol mono-n-butyl ether; (Poly)alkylene glycol monoalkyl ether acetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol methyl ether acetate (PGMEA), and propylene glycol ethyl ether acetate; other ethers such as diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, and cyclopentyl methyl ether; ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, 3-heptanone, 4-heptanone, 5-methyl-3-heptanone, 2,4-dimethyl-3-pentanone, and 2,6-dimethyl-4-heptanone; alkyl lactate esters such as methyl 2-hydroxypropionate and ethyl 2-hydroxypropionate;Other esters such as ethyl 2-hydroxy-2-methylpropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutylpropionate, ethyl acetate, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, n-pentyl formate, i-pentyl acetate, n-butyl propionate, ethyl butyrate, n-propyl butyrate, i-propyl butyrate, n-butyl butyrate, methyl pyruvate, ethyl pyruvate, n-propyl pyruvate, methyl acetoacetate, ethyl acetoacetate, and ethyl 2-oxobutanoate; alicyclic hydrocarbons such as cyclohexane, methylcyclohexane, ethylcyclohexane, and dimethylcyclohexane; Alcohols having 4 to 7 carbon atoms such as 1-butanol, 2-butanol, 1-pentanol (amyl alcohol), 2-pentanol, 3-pentanol, 2-methyl-2-butanol (tert-amyl alcohol), 3-methyl-1-butanol (isoamyl alcohol), 3-methyl-2-butanol (isopropylmethylcarbinol), 1-hexanol, 2-hexanol, 3-hexanol, 2-methyl-1-pentanol, 3-methyl-1-pentanol, 2-methyl-2-pentanol, 4-methyl-2-pentanol, 3-methyl-2-hexanol, 2,4-dimethyl-3-pentanol, 2-heptanol, 3-heptanol, and 4-heptanol; and aromatic ethers such as anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 3,4-dimethoxytoluene, and 1,4-bis(methoxymethyl)benzene. The organic solvent as component (B) may be used alone or in combination with several other types, taking into consideration miscibility with component (A).

[0051] In one aspect of the present invention, from the viewpoint of further improving the coatability of the polysiloxane composition and forming a high-quality coating film, it is preferable that component (B) contains an organic solvent selected from the group consisting of propylene glycol alkyl ether compounds, alkylcycloalkane compounds, and alcohols having 4 to 7 carbon atoms. Specific preferred examples of the propylene glycol alkyl ether compound include, but are not limited to, propylene glycol methyl ether and propylene glycol methyl ether acetate. Specific preferred examples of the alkylcycloalkane compound include, but are not limited to, methylcyclohexane and ethylcyclohexane. Specific preferred examples of the alcohols having 4 to 7 carbon atoms include, but are not limited to, 4-methyl-2-pentanol.

[0052] In one embodiment of the present invention, from the viewpoint of further improving the coatability of the polysiloxane composition and forming a high-quality coating film, it is particularly preferable that component (B) contains methylcyclohexane. In this embodiment, methylcyclohexane can be used alone as component (B), or a mixed solvent of methylcyclohexane with the other solvents described above can also be used. Here, the other solvent to be mixed with methylcyclohexane is preferably a propylene glycol alkyl ether compound such as propylene glycol methyl ether or propylene glycol methyl ether acetate.

[0053] <<Content of Component (B)>> As described above, the amount of component (B) contained in the polysiloxane composition of the present invention must be 10 parts by mass or more and 90 parts by mass or less, relative to 100 parts by mass of the total mass of components (A) and (B). When the amount of component (B) per 100 parts by mass of the total of components (A) and (B) is within the above-mentioned range, the storage stability and coatability of the polysiloxane composition to a substrate can be ensured. Furthermore, it becomes easier to control the film thickness of a coating film formed from the polysiloxane composition. In one aspect of the present invention, from the viewpoint of further improving the storage stability and coatability of the polysiloxane composition to a substrate, the amount of component (B) contained in the polysiloxane composition of the present invention is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, even more preferably 40 parts by mass or more, particularly preferably 50 parts by mass or more, relative to 100 parts by mass of the total mass of components (A) and (B). It is preferably 80 parts by mass or less, and more preferably 70 parts by mass or less.

[0054] In one embodiment of the present invention, the amount of component (B) contained in the polysiloxane composition of the present invention is, from the viewpoint of further improving the storage stability and coatability to a substrate of the polysiloxane composition, preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 40% by mass or more, and particularly preferably 50% by mass or more, and is preferably 80% by mass or less, and more preferably 70% by mass or less, based on the total mass of the polysiloxane composition being 100% by mass.

[0055] <Other Components> The polysiloxane composition of the present invention may contain other components in addition to the above-described components (A) and (B). In one embodiment of the present invention, the polysiloxane composition may contain a small amount of an organic solvent other than component (B), i.e., at least one of benzene, toluene, ethylbenzene, and xylene. However, from the viewpoint of further improving safety to living organisms, the total amount of benzene, toluene, ethylbenzene, and xylene contained in the polysiloxane composition of the present invention is preferably 1% by mass or less, more preferably 0.5% by mass or less, even more preferably 0.3% by mass or less, particularly preferably 0.1% by mass or less, and most preferably 0% by mass (below the detection limit), based on the total mass of the polysiloxane composition being 100% by mass. In another embodiment of the present invention, the polysiloxane composition may optionally contain an additional additive as component (C). Examples of additives include, but are not limited to, the following:

[0056] <<Adhesion Imparting Agent>> In one embodiment of the present invention, the polysiloxane composition can contain an adhesion imparting agent to improve adhesion to substrates. When the polysiloxane composition of the present invention is used in applications requiring adhesion to substrates, such as coating agents and sealants, it is preferable to add an adhesion imparting agent to the composition of the present invention. As this adhesion imparting agent, any known adhesion imparting agent can be used as long as it does not interfere with the step of removing component (B) from the polysiloxane composition of the present invention. Note that one type of adhesion imparting agent may be used alone, or multiple types may be used in combination.

[0057] The adhesion promoter is not particularly limited, but examples thereof include: organosilanes having a trialkoxysiloxy group (e.g., trimethoxysiloxy group, triethoxysiloxy group) and / or trialkoxysilylalkyl group (e.g., trimethoxysilylethyl group, triethoxysilylethyl group), and a hydrosilyl group and / or an alkenyl group (e.g., vinyl group, allyl group); organosiloxane oligomers having a linear, branched, or cyclic structure and about 4 to 20 silicon atoms, and having a trialkoxysiloxy group and / or trialkoxysilylalkyl group, and a hydrosilyl group and / or an alkenyl group; organosilanes having a trialkoxysiloxy group and / or trialkoxysilylalkyl group, and a methacryloxyalkyl group (e.g., 3-methacryloxypropyl group); Organosiloxane oligomers having a linear, branched, or cyclic structure and having about 4 to 20 silicon atoms, which have a trialkoxysiloxy group and / or a trialkoxysilylalkyl group and a methacryloxyalkyl group; organosilanes having a trialkoxysiloxy group and / or a trialkoxysilylalkyl group and an epoxy group-bonded alkyl group (e.g., 3-glycidoxypropyl group, 4-glycidoxybutyl group, 2-(3,4-epoxycyclohexyl)ethyl group, 3-(3,4-epoxycyclohexyl)propyl group); organosiloxane oligomers having a linear, branched, or cyclic structure and having about 4 to 20 silicon atoms, which have a trialkoxysiloxy group and / or a trialkoxysilylalkyl group and an epoxy group-bonded alkyl group; organic compounds having two or more trialkoxysilyl groups (e.g., trimethoxysilyl group, triethoxysilyl group); reaction products of aminoalkyltrialkoxysilanes and epoxy group-bonded alkyltrialkoxysilanes; epoxy group-containing ethyl polysilicate;

[0058] More specifically, the adhesion promoter is not particularly limited, but examples thereof include vinyltrimethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, hydrogentriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 1,6-bis(trimethoxysilyl)hexane, 1,6-bis(triethoxy ...

[0033] Examples of suitable silanol-blocking agents include tris(3-trimethoxysilyl)hexane, 1,3-bis[2-(trimethoxysilyl)ethyl]-1,1,3,3-tetramethyldisiloxane, a reaction product of 3-glycidoxypropyltriethoxysilane and 3-aminopropyltriethoxysilane, a condensation reaction product of a silanol-blocking methylvinylsiloxane oligomer and 3-glycidoxypropyltrimethoxysilane, a condensation reaction product of a silanol-blocking methylvinylsiloxane oligomer and 3-methacryloxypropyltriethoxysilane, and tris(3-trimethoxysilylpropyl)isocyanurate.

[0059] In one embodiment of the present invention, when the polysiloxane composition contains an adhesion promoter, the amount thereof is not particularly limited, but from the viewpoint of suppressing discoloration of a solid material obtained from the composition while sufficiently exhibiting adhesion, the amount thereof is preferably 0.01 parts by mass or more, preferably 5 parts by mass or less, and more preferably 2 parts by mass or less, per 100 parts by mass of component (A).

[0060] <<Other Additives>> In one embodiment of the present invention, other additives may be added to the polysiloxane composition as desired, in addition to or instead of the adhesion promoter described above. Examples of such other additives include, but are not limited to, leveling agents, wettability improvers, silane coupling agents not included in the adhesion promoters described above, high-energy ray absorbers, antioxidants, polymerization inhibitors, fillers (functional fillers such as reinforcing fillers, insulating fillers, hollow fillers, and thermally conductive fillers), and thixotropy-imparting agents. These additives may be used alone or in combination. Thixotropy-imparting agents are particularly useful when the polysiloxane composition of the present invention is used as a sealing material.

[0061] <Method for Preparing Polysiloxane Composition> The method for preparing the polysiloxane composition of the present invention is not particularly limited. For example, the polysiloxane composition of the present invention can be prepared by mixing component (A) and component (B), as well as other components used as needed, using a known method.

[0062] (Use of Polysiloxane Composition) The use of the polysiloxane composition of the present invention is not particularly limited. In one embodiment of the present invention, the polysiloxane composition can be used as an insulating coating agent, and an insulating coating can be formed using the polysiloxane composition. In another embodiment of the present invention, a display device can include a layer made of a solid material formed using the polysiloxane composition.

[0063] The processing method of the polysiloxane composition of the present invention for various uses will be described below. In one embodiment of the present invention, the processing method of the polysiloxane composition includes a step of applying the polysiloxane composition to a substrate (hereinafter referred to as the "application step") and a step of removing component (B) from the polysiloxane composition on the substrate (hereinafter referred to as the "organic solvent removal step").

[0064] In the coating step, the method for coating the polysiloxane composition onto the substrate is not particularly limited, and known methods using coating devices such as spin coaters, roll coaters, bar coaters, and slit coaters can be used. The type of substrate is also not particularly limited, and known substrates such as silicon wafers can be used depending on the intended use of the polysiloxane composition. In the organic solvent removal step, the method for removing component (B) from the polysiloxane composition is not particularly limited. In one embodiment of the present invention, component (B) can be removed by drying with heat. By heating the polysiloxane composition coated on the substrate, the organic solvent component (B) is dried and removed, and a solid product such as a coating film can be obtained. The heating method and conditions are not particularly limited, and examples include drying on a hot plate or in an oven at a temperature of 80 to 120°C, preferably 90 to 110°C, for 1 to 5 minutes; leaving the composition at room temperature for several hours; and heating in a hot air heater or infrared heater for several tens of minutes to several hours. If the polysiloxane composition of the present invention contains at least one organic solvent selected from the group consisting of benzene, toluene, ethylbenzene, and xylene, it is preferable to remove the organic solvent together with component (B) in the organic solvent removal step. The solid obtained through the organic solvent removal step can be used as is for any application, such as insulating coating. Furthermore, in the organic solvent removal step, it is also possible to react the reactive groups (OZ groups) remaining in the branched polysiloxane molecules by extending the heating time and / or increasing the heating temperature (e.g., 200 to 250°C). Such treatment allows for the production of a solid with an increased specific gravity.

[0065] In the present invention, the viscosity of the polysiloxane composition and / or the rate of production of a solid formed using the polysiloxane composition can be controlled by changing the structure, boiling point, and / or amount of the organic solvent used as component (B). Furthermore, in the present invention, the desired refractive index and mechanical properties of the solid can be designed by changing the molecular structure of the branched polysiloxane used as component (A) and / or the ratio of remaining reactive groups (OZ groups). The shape of the solid (branched polysiloxane solid) obtained by removing component (B) from the polysiloxane composition disclosed as one embodiment of the present invention is not particularly limited and may be a thin-film coating or a molded product such as a sheet. In one embodiment of the present invention, the solid may be used as a sealant or intermediate layer for laminates or display devices. In another embodiment of the present invention, the solid is preferably in the form of a thin-film coating, and more preferably a thin-film insulating coating. Such insulating coatings are particularly useful, for example, as materials for forming insulating layers constituting electronic and electrical devices.

[0066] Furthermore, since the solid formed using the polysiloxane composition of the present invention has good transparency, an insulating coating made of the solid is suitable as a material for forming an insulating layer in a display device such as a touch panel or a display. In this case, the insulating layer may be formed into any desired pattern as needed. Therefore, a display device such as a touch panel or a display, which includes an insulating layer made of a solid formed using the polysiloxane composition of the present invention, can also be cited as an embodiment of the present invention.

[0067] The present invention will be further described below based on examples, but the present invention is not limited to the following examples. The following methods were employed for various measurements and evaluations.

[0068] <Appearance of Polysiloxane Composition and Obtained Solid> The polysiloxane composition and the obtained solid were visually observed, and the appearance including transparency was evaluated.

[0069] <Average unit formula of branched polysiloxane and silanol group content> Deuterated acetone was used as a solvent. １３ C-NMR and ２９ The molar concentrations of each siloxane unit and silanol group were calculated by Si-NMR spectroscopy, and the average unit formula and silanol group content were identified.

[0070] <Molecular Weight and PDI of Branched Polysiloxane> Gel permeation chromatography (GPC) analysis was performed using tetrahydrofuran as an eluent to measure the weight average molecular weight (Mw) and number average molecular weight (Mn) in terms of standard polystyrene. From these values, the PDI (Mw / Mn) was calculated.

[0071] <Storage Stability of Polysiloxane Composition> The viscosity η0 of the prepared polysiloxane composition was measured at 25°C using a Brookfield viscometer in accordance with JIS K7117-1. After measuring the viscosity η0, the polysiloxane composition was stored in a refrigerator at 5°C for 30 days, and the viscosity η1 after storage was measured in the same manner as for η0. The viscosity increase rate (%) = (η1 - η0) / η0 × 100 was calculated, and the storage stability was evaluated according to the following criteria. A smaller viscosity increase rate value indicates better storage stability of the polysiloxane composition. A: Viscosity increase rate is 10% or less B: Viscosity increase rate is more than 10% and less than 30% C: Viscosity increase rate is more than 30%

[0072] <Coating Properties of Polysiloxane Composition> The prepared polysiloxane composition was spin-coated onto a silicon wafer substrate to a thickness of 4 μm. The polysiloxane composition on the substrate was heated in an oven at 100° C. for 5 minutes to form a coating film. This coating film was inspected and evaluated according to the following criteria: A: No coating unevenness, coating thickness uniform; B: Coating unevenness was observed in parts (5% or less of the total coating area), but the coating thickness was approximately uniform enough to cause no problems in practical use; C: Coating unevenness was observed over a wide area (more than 5% of the total coating area), causing problems in practical use.

[0073] <Tackiness (surface tackiness) of coating film surface formed using polysiloxane composition> A coating film was formed on a silicon wafer in the same manner as in "Coating property of polysiloxane composition". The surface of this coating film was touched with a finger to evaluate the surface tackiness. A: No tackiness B: Slight tackiness was observed, but the liquid did not adhere to the finger C: Severe tackiness was observed, and the liquid adhered to the finger

[0074] <Refractive index of branched polysiloxane> A coating film was formed on a silicon wafer in the same manner as in "Coating property of polysiloxane composition." The refractive index of this coating film made of branched polysiloxane at a wavelength of 633 nm was measured under the following conditions. Measuring device: Film thickness / refractometer "Model 2010 / M Prism Coupler" (manufactured by Metricon) Measurement temperature: Room temperature (25°C)

[0075] Synthesis Example 1: Branched Polysiloxane (A-1) A 100 mL three-neck flask equipped with a thermometer, a stirrer, and a nitrogen inlet tube was charged with 22.5 g of methyltrimethoxysilane and 1.5 g of hexamethyldisiloxane as starting materials, 0.35 g of a 1 mol / L aqueous hydrochloric acid solution as an acid catalyst, 5.9 g of water, and 50 g of PGMEA as a reaction solvent. This mixture was refluxed at 60°C in an oil bath for 2 hours to carry out a hydrolysis and condensation reaction. Methanol and excess water were removed from the resulting reaction solution by raising the bath temperature to 120°C. The reaction solution was then cooled to 40°C or below, and a 34% by mass aqueous potassium hydroxide solution as a basic catalyst was added to the reaction solution. 25 g of water was then added to the reaction solution, and the mixture was again heated to 120°C, and the water and PGMEA were removed as an azeotrope. After the reaction solution was cooled to room temperature, the solid was filtered off and the volatile components were distilled off under reduced pressure to obtain a colorless PGMEA solution of branched polysiloxane (A-1). １３ C and ２９Analysis was performed by Si NMR spectroscopy and gel permeation chromatography (GPC). As a result, it was confirmed that the branched polysiloxane (A-1) was a poly(trimethylsiloxane / methylsiloxane) copolymer with a trimethylsilyl group / methylsilyl group molar ratio of 9 / 91. Furthermore, the amount of OZ groups was 0.28 mol per mole of silicon atoms, and the amount of silanol groups was 0.26 mol per mole of silicon atoms. The Mw was 9,700, and the PDI was 5.2.

[0076] From the above results, the branched polysiloxane (A-1) has the following average unit formula (1): a = 0.09, b = 0, c = 0.91, d = 0, e = 0.28 (0.26 + 0.02), R １ = methyl group, R ２ It was found to have the following average unit formula: [(CH3)3SiO], where ≡ = hydrogen atoms and methyl groups. 1／2 ] 0.09 [(CH3)SiO 3／2 ] 0.91 [HO 1／2 ] 0.26 [(CH3)O 1／2 ] 0.02

[0077] Synthesis Example 2: Branched Polysiloxane (A-2) A 500 mL three-neck flask equipped with a thermometer, a stirrer, and a nitrogen inlet tube was charged with 133.0 g of methyltrimethoxysilane and 14.0 g of hexamethyldisiloxane as starting materials, 4.1 g of a 1 mol / L aqueous hydrochloric acid solution as an acid catalyst, 38 g of water, and 137 g of PGME as a reaction solvent. This mixture was refluxed at 60°C in an oil bath for 2 hours to carry out a hydrolysis and condensation reaction. Methanol and excess water were removed from the resulting reaction solution by raising the bath temperature to 110°C. Next, 7 g of water was added to the reaction solution, and the mixture was heated to 120°C, and the water and PGME were removed as an azeotrope. After cooling the reaction mixture to room temperature, a 34% by mass aqueous potassium hydroxide solution was added to the reaction mixture. The solid was filtered off, and the volatile components were removed by distillation under reduced pressure to obtain a colorless PGME solution of branched polysiloxane (A-2). The obtained branched polysiloxane (A-2) was analyzed in the same manner as in Synthesis Example 1. As a result, it was confirmed that the branched polysiloxane (A-2) was a poly(trimethylsiloxane / methylsiloxane) copolymer with a molar ratio of trimethylsilyl groups / methylsilyl groups of 11 / 89. Furthermore, the amount of OZ groups was 0.16 mol per mol of silicon atoms, and the amount of silanol groups was 0.15 mol per mol of silicon atoms. The Mw was 3,500, and the PDI was 2.6.

[0078] From the above results, it can be seen that the branched polysiloxane (A-2) has the following average unit formula (1): a = 0.11, b = 0, c = 0.89, d = 0, e = 0.16 (0.15 + 0.01), R １ = methyl group, R ２ It was found to have the following average unit formula: [(CH3)3SiO], where ≡ = hydrogen atoms and methyl groups. 1／2 ] 0.11 [(CH3)SiO 3／2 ] 0.89 [HO 1／2 ] 0.15 [(CH3)O 1／2 ] 0.01

[0079] Synthesis Example 3: Branched Polysiloxane (A-3) A 500 mL three-neck flask equipped with a thermometer, a stirrer, and a nitrogen inlet tube was charged with 118.3 g of methyltrimethoxysilane and 30.0 g of hexamethyldisiloxane as starting materials, 2.1 g of a 1 mol / L aqueous hydrochloric acid solution as an acid catalyst, 48 g of water, and 222.4 g of methylcyclohexane as a reaction solvent. This mixture was refluxed at 60°C for 2 hours using a mantle heater to carry out a hydrolysis and condensation reaction. After the resulting reaction solution was cooled to below 40°C, 0.57 g of a 34% by weight aqueous potassium hydroxide solution as a basic catalyst was added to the reaction solution and stirred for 30 minutes. The set temperature was then raised to 90°C, and methanol and excess water were removed from the reaction solution as an azeotrope with methylcyclohexane. After the reaction solution reached 90°C, it was stirred for an additional 1 hour. After cooling the reaction solution to below 60°C, 4 g of an adsorbent (Kyowa Chemical Industry Co., Ltd., "Kyoward (registered trademark) 700PL") was added, and the mixture was stirred at the same temperature for 30 minutes. The solid was filtered off, and the volatile components were removed by distillation under reduced pressure, yielding a colorless methylcyclohexane solution of branched polysiloxane (A-3). The resulting branched polysiloxane (A-3) was analyzed in the same manner as in Synthesis Example 1. As a result, it was confirmed that branched polysiloxane (A-3) was a poly(trimethylsiloxane / methylsiloxane) copolymer with a molar ratio of trimethylsilyl groups / methylsilyl groups of 20 / 80. Furthermore, the amount of OZ groups was 0.075 mol per mole of silicon atoms, and the amount of silanol groups was 0.075 mol per mole of silicon atoms. The Mw was 113,500, and the PDI was 21.

[0080] From the above results, it can be seen that the branched polysiloxane (A-3) has the following average unit formula (1): a = 0.2, b = 0, c = 0.8, d = 0, e = 0.075, R １ = methyl group, R ２ It was found to have the following average unit formula: [(CH3)3SiO] where SiO = hydrogen atom. 1／2 ] 0.2 [(CH3)SiO 3／2 ] 0.8 [HO 1／2 ] 0.075

[0081] Synthesis Example 4: Branched Polysiloxane (A-4) A 300 mL three-neck flask equipped with a thermometer, a stirrer, and a nitrogen inlet tube was charged with 33.4 g of methyltrimethoxysilane, 45.5 g of n-propyltrimethoxysilane, and 7.5 g of hexamethyldisiloxane as starting materials, 87 g of methylcyclohexane as a reaction solvent, and 1.2 g of hydrochloric acid as an acid catalyst (as hydrogen chloride, an amount equivalent to 500 ppm by mass of the total silicon raw material). This mixture was stirred at 60°C in an oil bath for 2 hours to carry out a hydrolysis and condensation reaction. The resulting reaction solution was cooled to 30°C or below, and an aqueous potassium hydroxide solution as a basic catalyst (as potassium hydroxide, an amount equivalent to 1000 ppm of the total silicon raw material) was added to the reaction solution, followed by stirring for an additional 30 minutes. The bath temperature was then raised to 100°C to remove methanol and excess water from the reaction solution, and the mixture was further stirred at an internal temperature of 90°C for 1 hour. After cooling the reaction solution to 50°C or below, 2 g of an adsorbent (Kyowa Chemical Industry Co., Ltd., "Kyoward 700PL") was added to the reaction solution, and the mixture was stirred at the same temperature for 30 minutes. The solid was filtered off, and the volatile components were distilled off under reduced pressure, yielding a colorless methylcyclohexane solution of branched polysiloxane (A-4). The branched polysiloxane (A-4) obtained was analyzed in the same manner as in Synthesis Example 1. As a result, it was confirmed that the branched polysiloxane (A-4) was a poly(trimethylsiloxane / methylsiloxane / n-propylsiloxane) copolymer in which the molar ratio of trimethylsilyl groups / methylsilyl groups / n-propylsilyl groups was 15 / 40 / 45. Furthermore, the amount of OZ groups was 0.03 mol per mole of silicon atoms, and the amount of silanol groups was 0.03 mol per mole of silicon atoms. The Mw was 18,800, and the PDI was 9.3.

[0082] From the above results, the branched polysiloxane (A-4) has the average unit formula (1) in which a = 0.15, b = 0, c = 0.85 (0.40 + 0.45), d = 0, e = 0.03, and R of the trifunctional siloxane unit １ = methyl group, R of monofunctional siloxane unit １ = methyl and n-propyl groups, R ２ It was found to have the following average unit formula: [(CH3)3SiO] where SiO = hydrogen atom.1／2 ] 0.15 [(CH3)SiO 3／2 ] 0.40 [(n-C3H7)SiO 3／2 ] 0.45 [HO 1／2 ] 0.03

[0083] Synthesis Example 5: Branched Polysiloxane (A-5) A 500 mL three-neck flask equipped with a thermometer, a stirrer, and a nitrogen inlet tube was charged with 187.5 g of methyltrimethoxysilane as a starting material, 0.68 g of oxalic acid as an acidic catalyst, 67.5 g of water, and 369 g of PGMEA as a reaction solvent. This mixture was refluxed in an oil bath at 70°C for 2 hours to carry out a hydrolysis and condensation reaction. Methanol and excess water were removed from the resulting reaction solution by raising the bath temperature to 100°C. The reaction mixture was then cooled to 50°C or below, and 8 g of an adsorbent (Kyowa Chemical Industry Co., Ltd., "KW-2000") was added to the reaction mixture, followed by stirring at the same temperature for 30 minutes. The solid was filtered off, and the volatile components were removed by distillation under reduced pressure to obtain a colorless PGMEA solution of branched polysiloxane (A-5). The resulting branched polysiloxane (A-5) was analyzed in the same manner as in Synthesis Example 1. As a result, it was confirmed that the branched polysiloxane (A-5) was polymethylsilsesquioxane. The amount of OZ groups was 0.49 mol per mol of silicon atoms, and the amount of silanol groups was 0.44 mol per mol of silicon atoms. The Mw was 3,000, and the PDI was 2.6.

[0084] Examples 1 to 4 and Comparative Examples 1 to 3 Polysiloxane compositions were prepared by mixing (A) a branched polysiloxane, (B) an organic solvent, and, if necessary, (C) an additive, in amounts of parts by mass as shown in Table 1. Coating films were then formed from the polysiloxane compositions, and various evaluations were carried out for the above-mentioned items. All of the results are shown in Table 1. Table 1 also shows the value of e in the average unit formula (1) and the amount of silanol groups.

[0085] The terms in Table 1 below have the following meanings. [e]: the value of e in the average unit formula (1) [Silanol]: the content of silanol groups (Si—OH) per mole of silicon atom in the branched polysiloxane (unit: mole) A-1: ​​branched polysiloxane (A-1) obtained in Synthesis Example 1 A-2: branched polysiloxane (A-2) obtained in Synthesis Example 2 A-3: branched polysiloxane (A-3) obtained in Synthesis Example 3 A-4: branched polysiloxane (A-4) obtained in Synthesis Example 4 A-5: branched polysiloxane (A-5) obtained in Synthesis Example 5 A-6: methoxy-functional polymethylsilsesquioxane ("DOWSIL (registered trademark) 2402" manufactured by The Dow Chemical Company) A-7: methoxy-functional poly(dimethylsiloxy / methylsiloxy) copolymer ("DOWSIL 2405" manufactured by The Dow Chemical Company) B-1: Propylene glycol methyl ether acetate (PGMEA) B-2: Propylene glycol monomethyl ether (PGME) B-3: Methylcyclohexane C-1: Dimethyl silicone oil (wettability improver, "DOWSIL SH 200 Fluid 20 cS" manufactured by The Dow Chemical Company)

[0086]

[0087] The polysiloxane compositions of Examples 1 to 4 had good storage stability, good coatability on silicon wafers, and were able to form uniform coating films. Furthermore, the refractive index of the coating films (branched polysiloxane solids) obtained from the polysiloxane compositions of Examples 1 to 4 was low, less than 1.45. Furthermore, the surfaces of the coating films obtained from the polysiloxane compositions of Examples 1 to 4 were free of tackiness, and the coating films had excellent transparency. On the other hand, the polysiloxane compositions of Comparative Examples 1 to 3, which contained branched polysiloxanes whose structural factors did not satisfy the conditions, were unable to achieve both storage stability and coatability. Specifically, in Comparative Examples 1 to 3, which used branched polysiloxanes with an OZ group ratio e exceeding 0.3, the storage stability or coatability of the polysiloxane compositions to substrates deteriorated.

[0088] According to the present invention, it is possible to provide a polysiloxane composition capable of forming a coating film having a low refractive index and exhibiting excellent storage stability and applicability to substrates, and uses thereof. Furthermore, the coating film formed using the polysiloxane composition of the present invention is of high quality, tack-free, and exhibits a low refractive index. Furthermore, the coating film formed using the resulting polysiloxane composition of the present invention has the advantage of being excellent in mechanical strength and transparency. Therefore, the polysiloxane composition of the present invention is useful as an insulating material for electric and electronic devices such as display devices. The polysiloxane composition of the present invention is also useful as an insulating coating agent, an anti-reflective coating material, and the like.

Claims

1. (A) The following average unit formula (1): [R 1 (CH3)2SiO 1 / 2 ] ａ [R 1 (CH3)SiO 2 / 2 ] b [R 1 SiO 3 / 2 ] c [SiO 4 / 2 ] d [R 2 O 1 / 2 ] e ...(1) (In formula (1), R １ each independently represents a hydrogen atom, a monovalent aliphatic hydrocarbon group having from 1 to 6 carbon atoms, or a monovalent aromatic hydrocarbon group having from 6 to 12 carbon atoms; R ２ a+b+c+d=1。 A polysiloxane composition comprising: (A) a branched polysiloxane having a refractive index of less than 1.45 at a wavelength of 633 nm, and (B) an organic solvent other than benzene, toluene, ethylbenzene, and xylene, and (C) an organic solvent other than benzene, toluene, ethylbenzene, and xylene, and (D) a branched polysiloxane having a refractive index of less than 1.45 at a wavelength of 633 nm, and (E) a branched polysiloxane having a refractive index of less than 1.45 at a wavelength of 633 nm, and (F) an organic solvent other than benzene, toluene, ethylbenzene, and xylene, and (G) a branched polysiloxane having a refractive index of less than 1.45 at a wavelength of 633 nm, and (H) a branched polysiloxane having a refractive index of less than 1.45 at a wavelength of 633 nm, and (I ... an organic solvent other than benzene, toluene, ethylbenzene, and xylene, and (I) a branched polysiloxane having a refractive index of less than 1.45 at a wavelength of 633 nm.

2. R in the average unit formula (1) ２ The polysiloxane composition of claim 1 , wherein comprises a hydrogen atom.

3. R ​​in the average unit formula (1) １ The polysiloxane composition according to claim 1 , wherein the polysiloxane composition contains a methyl group and does not contain a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms.

4. R in the average unit formula (1) １ The polysiloxane composition according to claim 1 , wherein each of the is independently a methyl group or an n-propyl group.

5. The polysiloxane composition according to claim 1, wherein b and d in the average unit formula (1) are 0.

6. The polysiloxane composition according to claim 1, wherein said component (B) comprises at least one selected from the group consisting of propylene glycol alkyl ether compounds, alkylcycloalkane compounds, and alcohols having 4 to 7 carbon atoms.

7. The polysiloxane composition of claim 1, wherein said component (B) comprises at least one selected from the group consisting of propylene glycol methyl ether, propylene glycol methyl ether acetate, methylcyclohexane, and ethylcyclohexane.

8. The polysiloxane composition of claim 1, wherein said component (B) comprises methylcyclohexane.

9. An insulating coating agent comprising the polysiloxane composition according to any one of claims 1 to 8.

10. An insulating coating formed using the polysiloxane composition according to any one of claims 1 to 8.

11. A method for producing an insulating coating, comprising the step of removing said component (B) from the polysiloxane composition according to any one of claims 1 to 8.

12. A display device comprising a layer made of a solid material formed using the polysiloxane composition according to any one of claims 1 to 8.

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