Branched organopolysiloxane, curable composition, and use thereof

Abstract

The present disclosure provides a branched organopolysiloxane. The branched organopolysiloxane of the present disclosure is represented by average unit formula (1), has one or more monovalent organic groups per molecule, each monovalent organic group having two hydrophilic groups, has one or more carboxy groups as a hydrophilic group per molecule, and has one or more ultraviolet curable groups per molecule. (1): [R1(CH3)2SiO1 / 2]a[RA(CH3)SiO2 / 2]b[RBSiO3 / 2]c[SiO4 / 2]d[HO1 / 2]e1[R2O1 / 2]e2 R1, RA, RB are each a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1-6 carbon atoms, a monovalent aromatic hydrocarbon group having 6-12 carbon atoms, a monovalent organic group having two hydrophilic groups, or an ultraviolet curable group. R2 is a monovalent hydrocarbon group having 1-4 carbon atoms. The following relationships are satisfied: 0 ≤ a ≤ 0.4; 0 ≤ b ≤ 0.5; 0.4 ≤ c < 1; 0 ≤ d ≤ 0.6; 0 ≤ e1 ≤ 0.2; 0 ≤ e2 ≤ 0.2; 0 ≤ e1 + e2 ≤ 0.2; a + b + c + d = 1; and a + b > 0.

Description

Branched organopolysiloxanes, curable compositions, and their uses

[0001] This disclosure relates to branched organopolysiloxanes, curable compositions, and their uses.

[0002] Organopolysiloxanes have been conventionally used as coatings, potting agents, and insulating materials for electronic and electrical devices due to their high heat resistance and excellent chemical stability.

[0003] Low refractive index materials are used in various display devices such as mobile devices, industrial equipment, and car navigation systems for purposes such as anti-reflective properties and protection of various functional components. Fluorine-based polymer materials are well-known as typical low refractive index materials. However, recent research has revealed concerns about the resilience, high bioaccumulation potential, and biosafety of fluorine-based polymer materials, leading to a global movement to regulate them. Organopolysiloxanes are attracting attention as alternative materials.

[0004] For example, materials containing organopolysiloxanes that are soluble in alkaline aqueous solutions as a developer (referred to as "alkali solubility") and are lithographically viable have been reported (see Patent Documents 1-4, etc.).

[0005] Japanese Patent Publication No. 2012-215837, Japanese Patent Publication No. 2020-184010, Japanese Patent Publication No. 2021-189314, Japanese Patent Publication No. 2004-205699

[0006] This disclosure provides branched organopolysiloxanes, curable compositions containing branched organopolysiloxanes, and applications thereof. Several embodiments disclosed herein aim to solve the problems of the above-mentioned prior art. For example, the above-mentioned prior art organopolysiloxane materials had room for improvement in that they could form coating films with a low refractive index while exhibiting good alkali solubility and UV curability.

[0007] The present inventor has found that a branched organopolysiloxane having a monovalent organic group having two hydrophilic groups and an ultraviolet curable group and having a predetermined composition can exhibit both good alkali solubility and ultraviolet curability, and that a curable composition containing the branched organopolysiloxane can form a coating film having a low refractive index.

[0008] According to the present disclosure, there are provided the branched organopolysiloxanes of [1] to [7] described below, the curable composition of [8], the insulating coating agent of [9], the insulating coating of

[10] , the manufacturing method of the insulating coating of

[11] , and the display device of

[12] .

[0009] [1] The following average unit formula (1): [R 1 (CH3)2SiO 1 / 2 a [R A (CH3)SiO 2 / 2 b [R B SiO 3 / 2 c [SiO 4 / 2 d [HO 1 / 2 e1 [R 2 O 1 / 2 e2 (1) (In formula (1), R １ , R Ａ , R Ｂ are each independently a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, a monovalent organic group having two hydrophilic groups, or an ultraviolet curable group, and R ２ ​​​​​​A branched organopolysiloxane is a monovalent hydrocarbon group having 1 to 4 carbon atoms, and a, b, c, d, e1 and e2 are numbers satisfying the following conditions: 0 ≤ a ≤ 0.4; 0 ≤ b ≤ 0.5; 0.4 ≤ c < 1; 0 ≤ d ≤ 0.6; 0 ≤ e1 ≤ 0.2; 0 ≤ e2 ≤ 0.2; 0 ≤ e1 + e2 ≤ 0.2; a + b + c + d = 1, a + b > 0. The branched organopolysiloxane is represented by ( ), and has on average one or more monovalent organic groups having two hydrophilic groups per molecule, on average one or more carboxyl groups as the hydrophilic groups per molecule, and on average one or more ultraviolet curable groups per molecule.

[0010] [2] The branched organopolysiloxane according to [1] above, wherein the ultraviolet curable group includes a (meth)acryloxy group.

[0011] [3] The branched organopolysiloxane according to [1] or [2] above, wherein the monovalent organic group having the two hydrophilic groups is an organic group represented by the following formula (2a) or (2b). *-R 3 -CH(OX 2 )CH2OX 1 (2a) (In formula (2a), R ３ X is a divalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, which may contain an oxygen atom. １ , X ２ Each is independently a hydrogen atom or -C(=O)-R ６ -CO ２ H[R ６ (where * is a divalent aliphatic hydrocarbon group having 1 to 4 carbon atoms, and * is a bonding site to a silicon atom.) (In formula (2b), R ４ R is a divalent aliphatic hydrocarbon group having 1 to 3 carbon atoms. ５ X is a hydrogen atom or a methyl group. １ , X ２ (This is equivalent to the above, where n is an integer between 1 and 4, and * represents the bonding site to the silicon atom.)

[0012] [4] A branched organopolysiloxane according to any one of [1] to [3] above, wherein d = 0 in the average unit formula (1).

[0013] [5] In the above average unit formula (1), R １, R Ｂ Each of these is independently a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, or an ultraviolet curable group, R Ａ The branched organopolysiloxane according to any one of [1] to [4] above, wherein b is a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, a monovalent organic group having two hydrophilic groups, or an ultraviolet curable group, and b ≤ 0.5.

[0014] [6] In the above average unit formula (1), R １ , R Ａ Each of these is independently a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, or an ultraviolet curable group, R Ｂ The branched organopolysiloxane according to any one of [1] to [4] above, wherein is a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, a monovalent organic group having two hydrophilic groups, or an ultraviolet curable group.

[0015] [7] The branched organopolysiloxane according to any one of [1] to [6] above, wherein the average number of carboxyl groups contained in each monovalent organic group in the branched organopolysiloxane is one or more, and the monovalent organic group is present in an average of two or more molecules.

[0016] [8] A curable composition comprising (A) a branched organopolysiloxane as described in any one of [1] to [7] above, (B) a photopolymerization initiator, and (C) an organic solvent, wherein the content of component (B) is 0.1 parts by mass or more and 10 parts by mass or less per 100 parts by mass of component (A).

[0017] [9] An insulating coating agent comprising the curable composition described in [8] above.

[0018]

[10] An insulating coating formed using the curable composition described in [8] above.

[0019]

[11] A method for producing an insulating coating, comprising the step of removing component (C) from the curable composition described in [8] above.

[0020]

[12] A display device comprising a layer made of a solid formed using the curable composition described in [8] above. The display device may be, for example, a liquid crystal display, an organic EL display, or an organic EL flexible display.

[0021] This disclosure provides branched organopolysiloxanes, curable compositions containing branched organopolysiloxanes, and applications thereof. In some embodiments disclosed herein, branched organopolysiloxanes that have good alkali solubility, maintain excellent UV curability, and can form coatings with a low refractive index, as well as curable compositions containing such branched organopolysiloxanes, can be provided.

[0022] Unless otherwise stated, unless implicitly stated in the context, or unless customary in the art, all "parts" and "%" are based on mass, all temperatures are in "°C", and all test methods are current as of the filing date of this disclosure. The numerical ranges described in this disclosure may be any combination of upper and lower limits. For example, if a numerical range is described as "30 to 100, or 40 to 80", the ranges of "30 to 80" and "40 to 100" are included in the numerical ranges described in this disclosure. Similarly, if a numerical range is described as "30 or more, or 40 or more, and 100 or less, or 80 or less", the ranges of "30 to 80" and "40 to 100" are included in the numerical ranges described in this disclosure. Furthermore, if a numerical range described in this disclosure is, for example, "60 to 100", it means the range is "60 or more, and 100 or less". In this disclosure, “monovalent organic group having two hydrophilic groups” refers to a monovalent organic group (a group whose main element is carbon) having a structure with at least two hydrophilic groups. In some embodiments, the number of hydrophilic groups on one such monovalent organic group may be 2 to 4, 2 to 3, or 2. In this disclosure, “hydrophilic group” refers to a group that has an affinity for water. In some embodiments, the “hydrophilic group” may be at least one selected from the group consisting of hydroxyl groups (including alcoholic hydroxyl groups and phenolic hydroxyl groups), carboxyl groups, sulfonic acid groups, and amino groups, or at least one of a hydroxyl group and a carboxyl group. The “hydrophilic group” may also be in the form of a salt, such as a sodium salt. In this disclosure, “ultraviolet curable group” refers to a group that can undergo a curing reaction not only with ultraviolet light (including extreme ultraviolet and far ultraviolet light) but also with any high-energy rays, such as electron beams. In this disclosure, “(meth)acryloxy” means acryloxy and / or methacryloxy. In this disclosure, "(thio)xanthene" means xanthene and / or thioxanthene. In this disclosure, "(thio)xanthone" means xanthone and / or thioxanthone.In this disclosure, “(thia)pyrillium” means pyrillium and / or thiapyrillium. In this disclosure, “a divalent aliphatic hydrocarbon group may contain an oxygen atom” means that the divalent aliphatic hydrocarbon group may optionally include a structure in which an oxygen atom is sandwiched between two carbon atoms (C-O-C). In this disclosure, “curable composition” means a composition that can be cured by any method. An example of a specific curing method is irradiation with high-energy rays such as ultraviolet light or electron beams. In this disclosure, the composition of a branched organopolysiloxane is as follows: １３ C-NMR spectroscopy and ２９ This can be determined by nuclear magnetic resonance spectroscopy, such as Si-NMR spectroscopy. In this disclosure, "weight-average molecular weight" and "number-average molecular weight" refer to the molecular weight on a standard polystyrene basis, measured by gel permeation chromatography (GPC), respectively. In this disclosure, the "refractive index at 633 nm" of the cured product refers to the refractive index at 633 nm measured in the state of the coating film after preparing the coating film by the method described in the examples below. In this disclosure, the "glass transition temperature" can be determined by a measurement method using differential scanning calorimeter.

[0023] <Branched organopolysiloxanes> The branched organopolysiloxanes of this disclosure are represented by the following average unit formula (1). [R 1 (CH3)2SiO 1 / 2 ] a [R A (CH3)SiO 2 / 2 ] b [R B SiO 3 / 2 ] c [SiO 4 / 2 ] d [HO 1 / 2 ] e1 [R 2 O 1 / 2 ] e2 (1)

[0024] In the above formula (1), R １ , R Ａ , R ＢEach of these is independently a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, a monovalent organic group having two hydrophilic groups, or an ultraviolet curable group, R ２ is a monovalent hydrocarbon group having 1 to 4 hydrogen atoms or carbon atoms. In formula (1) above, a, b, c, d, e1 and e2 (all in molar ratios) are numbers that satisfy the following conditions: 0 ≤ a ≤ 0.4; 0 ≤ b ≤ 0.5; 0.4 ≤ c < 1; 0 ≤ d ≤ 0.6; 0 ≤ e1 ≤ 0.2; 0 ≤ e2 ≤ 0.2; 0 ≤ e1 + e2 ≤ 0.2; a + b + c + d = 1, a + b > 0. The branched organopolysiloxane of this disclosure has, on average, one or more monovalent organic groups having two hydrophilic groups and, on average, one or more UV-curable groups per molecule. 1 (CH3)2SiO 1 / 2 "'s R １ There may be one type or two or more types. That is, the branched organopolysiloxane may contain only one type of M unit or two or more types. The D unit is "R A (CH3)SiO 2 / 2 "'s R A There may be one type or two or more types. That is, a branched organopolysiloxane may contain only one type of D unit or two or more types. The T unit is "R B SiO 3 / 2 "'s R B There may be one type or two or more types. That is, the branched organopolysiloxane may contain only one type of T unit or two or more types. The remaining reactive group is "R 2 O 1 / 2 ” (hereinafter referred to as “R 2 O 1 / 2 " and "HO 1 / 2 The term "OZ group" is sometimes used to refer to all of these together. ２ This may be one type or two or more types. In other words, the branched organopolysiloxane may contain only one type of reactive group or two or more types.

[0025] In the above formula (1), R１ , R Ａ , R Ｂ As described above, each of these is independently a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, a monovalent organic group having two hydrophilic groups, or an ultraviolet-curable group. １ , R Ａ , R Ｂ The monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms is not particularly limited, but examples include linear or branched aliphatic saturated hydrocarbon groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, sec-butyl, pentyl, and hexyl groups; cyclic aliphatic saturated hydrocarbon groups such as cyclopentyl and cyclohexyl groups; and alkenyl groups such as vinyl, allyl, butenyl, and hexenyl groups. １ , R Ａ , R Ｂ The monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms is not particularly limited, but examples include aryl groups such as phenyl and naphthyl groups; and arylalkyl groups such as benzyl and phenylethyl groups. １ , R Ａ , R Ｂ As the UV-curable group constituting the UV-curable group, an organic group containing at least a part of a chemical structure that is reactive to ultraviolet light can be preferably used. Examples of chemical structures that are reactive to ultraviolet light include epoxy groups, oxetane groups, vinyl ether groups, and (meth)acryloxy groups. The UV-curable group may have only one type of chemical structure that is reactive to ultraviolet light, or it may have multiple types. In some embodiments, from the viewpoint of ease of manufacture and availability of raw materials, the UV-curable group may be an organic group containing at least one of an epoxy group and a (meth)acryloxy group, or an organic group containing a (meth)acryloxy group. Examples of organic groups containing a (meth)acryloxy group include methacryloxypropyl groups and acryloxypropyl groups.

[0026] In some embodiments, from the viewpoint of reducing the refractive index of the coating film, R in formula (1) above １ , RＡ , R Ｂ may contain at least one of a linear aliphatic saturated hydrocarbon group and an alkenyl group, or may contain at least one selected from the group consisting of a methyl group, a vinyl group, and an n-propyl group, or may contain at least one of a methyl group and an n-propyl group, or may contain a methyl group.

[0027] In some embodiments, from the perspective of reducing the refractive index of the coating film, R in the above formula (1) １ , R Ａ , R Ｂ may not contain any monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms. Also, in some embodiments, from the perspective of reducing the refractive index of the coating film, R excluding the monovalent organic group having two hydrophilic groups and the ultraviolet curable group in the above formula (1) １ , R Ａ , R Ｂ may all be at least one of a methyl group and an n-propyl group, or may all be methyl groups.

[0028] In some embodiments, the monovalent organic group having two hydrophilic groups constituting R １ may be an organic group composed of only carbon atoms, hydrogen atoms, and oxygen atoms. Also, in some embodiments, the number of carbon atoms of the monovalent organic group having two hydrophilic groups may be 9 to 16, or 10 to 14.

[0029] In some embodiments, the monovalent organic group having two hydrophilic groups may be an organic group represented by the following formula (2a) and / or an organic group represented by the following formula (2b).

[0030] *-R 3 -CH(OX 2 )CH2OX 1 (2a) In the above formula (2a), R ３ is a divalent aliphatic hydrocarbon group having 1 to 6 carbon atoms which may contain an oxygen atom, and X １ , X ２ are each independently a hydrogen atom or -C(=O)-R ６ -CO ２ H [R６ X is a divalent aliphatic hydrocarbon group having 1 to 4 carbon atoms, and * is a bonding site to a silicon atom. In some embodiments, X １ and X ２ Both cannot be hydrogen atoms at the same time; in other words, X １ , X ２ Either or both of these are -C(=O)-R ６ -CO ２ The above R may be a carboxyl group-containing group represented by an H group. ３ Examples of these groups, though not particularly limited, include ethylene groups, propylene groups, butylene groups, and propyleneoxymethylene groups. In some embodiments, R ３ R may be a propyleneoxymethylene group. ６ Examples include, but are not particularly limited, linear alkylene groups such as ethylene groups, propylene groups, and butylene groups, and branched alkylene groups such as methylethylene groups. In some embodiments, R ６ is also an ethylene group. In some embodiments, the organic group represented by formula (2a) above may be at least one selected from the group consisting of 1-carboxyethylcarbonyloxy-2-hydroxybutyl group, 1,2-di(carboxyethylcarbonyloxy)butyl group, 1-carboxyethylcarbonyloxy-2-hydroxyhexyl group, 1,2-di(carboxyethylcarbonyloxy)hexyl group, 1-carboxyethylcarbonyloxy-2-hydroxypropyloxypropyl group, and 1,2-di(carboxyethylcarbonyloxy)propyloxypropyl group. Alternatively, the organic group represented by formula (2a) above may be at least one of 1-carboxyethylcarbonyloxy-2-hydroxypropyloxypropyl group and 1,2-di(carboxyethylcarbonyloxy)propyloxypropyl group.

[0031] In the above formula (2b), R ４ R is a divalent aliphatic hydrocarbon group having 1 to 3 carbon atoms. ５ X is a hydrogen atom or a methyl group, １ and X ２(and R among these ６ ) is equivalent to formula (2a), where n is an integer between 1 and 4, and * is a bonding site to a silicon atom. In some embodiments, X １ and X ２ Both of them cannot be hydrogen atoms; in other words, X １ , X ２ Either or both of these are C=O-R ６ -CO ２ The above R may be a carboxyl group-containing group represented by an H group. ４ Examples include, but are not limited to, methylene groups, ethylene groups, and propylene groups. In some embodiments, R ４ R may be an ethylene group. In some embodiments, the above R ５ n may be a hydrogen atom. In some embodiments, n may be 2. In some embodiments, the above R ６ is also an ethylene group. And in some embodiments, the organic group represented by formula (2b) above may be at least one selected from the group consisting of 2-(3-hydroxy-4-carboxyethylcarbonyloxycyclohexyl)ethyl group, 2-(3-carboxyethylcarbonyloxy-4-hydroxycyclohexyl)ethyl group, 3-(3-hydroxy-4-carboxyethylcarbonyloxycyclohexyl)propyl group, 3-(3-carboxyethylcarbonyloxy-4-hydroxycyclohexyl)propyl group, 2-(3,4-di(carboxyethylcarbonyloxy)cyclohexyl)ethyl group, 3-(3,4-di(carboxyethylcarbonyloxy)cyclohexyl)propyl group, or It may be at least one selected from the group consisting of 2-(3-hydroxy-4-carboxyethylcarbonyloxycyclohexyl)ethyl group, 2-(3-carboxyethylcarbonyloxy-4-hydroxycyclohexyl)ethyl group, and 2-(3,4-di(carboxyethylcarbonyloxy)cyclohexyl)ethyl group.

[0032] In some embodiments of this disclosure, in formula (1) above, R１ , R Ｂ Each of these is independently a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, or an ultraviolet curable group, R Ａ The group may be a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, a monovalent organic group having two hydrophilic groups, or an ultraviolet curable group. That is, the branched organopolysiloxane of this disclosure is a D unit ("R A (CH3)SiO 2 / 2 It may have a monovalent organic group having two hydrophilic groups only on the ) surface.

[0033] In another embodiment of this disclosure, in formula (1) above, R １ , R Ａ Each of these is independently a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, or an ultraviolet curable group, R Ｂ This may be a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, a monovalent organic group having two hydrophilic groups, or an ultraviolet curable group. That is, the branched organopolysiloxane of this disclosure is a T unit ("R" B SiO 3 / 2 It may have a monovalent organic group having two hydrophilic groups only on the ) surface.

[0034] In some embodiments, the branched organopolysiloxane may have UV-curable groups on at least one of the D units and the T units, or it may have UV-curable groups on the T units.

[0035] In the above formula (1), R ２ As mentioned above, R is a monovalent hydrocarbon group having 1 to 4 carbon atoms. ２ Examples of such groups, though not particularly limited, include methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, and sec-butyl groups. In some embodiments, R ２This may be at least one of a methyl group and an ethyl group, or it may be a methyl group.

[0036] In the above formula (1), the unit is "R 1 (CH3)2SiO 1 / 2 The ratio a of " satisfies 0 ≤ a ≤ 0.4 (in other words, 0 or more and 0.4 or less). That is, the M units do not have to be included in the branched organopolysiloxane. In some embodiments, the ratio a may be greater than 0, or 0.1 or more, or 0.2 or more. At the same time, the ratio a may be 0.35 or less, or 0.3 or less, or 0.25 or less. When the ratio a is greater than 0, i.e., when the branched polyorganosiloxane contains M units, it becomes easier to control the molecular weight of the branched organopolysiloxane. On the other hand, when the ratio a is 0.4 or less, it is possible to suppress the decrease in the softening point and strength (coating strength) of the coating film formed using the curable composition.

[0037] In the above formula (1), the unit D is "R A (CH3)SiO 2 / 2 The ratio b of the branched organopolysiloxane satisfies 0 ≤ b ≤ 0.5 (in other words, 0 or more and 0.5 or less). That is, D units do not have to be included in the branched organopolysiloxane. In some embodiments, the ratio b may be greater than 0, or 0.1 or more, or 0.15 or more. At the same time, the ratio b may be 0.4 or less, or 0.3 or less, or 0.2 or less. By having a ratio b of 0.5 or less, it is possible to suppress the decrease in the softening point and strength (coating strength) of the coating film formed using the curable composition. As mentioned above, in some embodiments, the branched organopolysiloxane does not have to contain D units. On the other hand, including D units in the branched organopolysiloxane has the advantages of making it easier to control the molecular weight of the branched organopolysiloxane and imparting flexibility to the coating film formed using the curable composition.

[0038] In the above formula (1), the ratio a of M units and the ratio b of D units satisfy a + b > 0. That is, branched organopolysiloxanes contain either M units or D units, or both. This makes it easy to control the molecular weight of branched polyorganosiloxanes.

[0039] In the above formula (1), the unit of T is "R B SiO 3 / 2 The ratio c of the branched polyorganosiloxane satisfies 0.4 ≤ c < 1 (in other words, 0.4 or more and less than 1). That is, the T unit is the main constituent unit of the branched polyorganosiloxane. In some embodiments, the ratio c may be 0.5 or more, or 0.6 or more, or 0.7 or more. A ratio c of 0.4 or more can raise the softening point of the coating film formed using the curable composition. In some embodiments, the ratio c may be 0.9 or less, or 0.8 or less.

[0040] In the above formula (1), the unit Q is "SiO 4 / 2 The ratio d of the branched polyorganosiloxane satisfies 0 ≤ d ≤ 0.6 (in other words, 0 or more and 0.6 or less). That is, the Q units do not have to be included in the branched polyorganosiloxane, just like the M units and D units mentioned above. In some embodiments, the ratio d may be 0.4 or less, or 0.2 or less, or 0.1 or less, or 0 (in other words, the branched polyorganosiloxane does not contain Q units). A ratio d of 0.6 or less can reduce the brittleness of the coating film formed using the curable composition. As mentioned above, in some embodiments, the branched polyorganosiloxane does not have to contain Q units. On the other hand, the branched polyorganosiloxane containing Q units has the advantage of being able to raise the softening point of the coating film formed using the curable composition.

[0041] In equation (1) above, the sum of the ratios a, b, c, and d satisfies a + b + c + d = 1.

[0042] In the above formula (1), "HO 1 / 2The ratio e1 of the group satisfies 0 ≤ e1 ≤ 0.2 (in other words, 0 or more and 0.2 or less). That is, the group in question (usually called a silanol group) does not have to be included in the branched organopolysiloxane. A ratio e1 of 0.2 or less improves the storage stability of the curable composition. In some embodiments, the ratio e1 may be 0.05 or more, or 0.1 or more. At the same time, the ratio e1 may be 0.15 or less, or 0.12 or less, or 0. Furthermore, a ratio e1 of 0.05 or more improves the alkali solubility of the branched organopolysiloxane.

[0043] In the above formula (1), "R 2 O 1 / 2 The ratio e2 of " satisfies 0 ≤ e2 ≤ 0.2 (in other words, 0 or greater and 0.2 or less). That is, "R 2 O 1 / 2 The group does not necessarily have to be included in the branched polyorganosiloxane. That is, the group does not necessarily have to be included in the branched organopolysiloxane. The storage stability of the curable composition can be improved by having a ratio e2 of 0.2 or less. In some embodiments, the ratio e2 may be 0.15 or less, or 0.1 or less, or 0.

[0044] In the above formula (1), the sum of ratio e1 and ratio e2 (e1 + e2) satisfies 0 ≤ e1 + e2 ≤ 0.2 (in other words, 0 or more and 0.2 or less). By keeping e1 + e2 at 0.2 or less, the storage stability of the curable composition can be improved. In some embodiments, e1 + e2 may be 0.15 or less, or 0.1 or less.

[0045] The branched organopolysiloxanes of this disclosure have an average of one or more UV-curable groups per molecule. In some embodiments, the average number of UV-curable groups per molecule of branched organopolysiloxane may be two or more, or three or more, from the viewpoint of ensuring sufficient UV curability. There is no particular upper limit to the average number of UV-curable groups per molecule of branched organopolysiloxane. For example, the average number may be eight or less, or six or less.

[0046] The branched organopolysiloxanes of this disclosure have, on average, one or more monovalent organic groups having two hydrophilic groups per molecule. In some embodiments, the average number of monovalent organic groups having two hydrophilic groups per molecule of branched organopolysiloxane may be two or more, three or more, four or more, or five or more, from the viewpoint of ensuring sufficient alkali solubility. There is no particular upper limit to the average number of monovalent organic groups having two hydrophilic groups per molecule. For example, the average number may be eight or less, or six or less.

[0047] In some embodiments, the average number of carboxyl groups contained in each monovalent organic group having two hydrophilic groups in the branched organopolysiloxane of the present disclosure may be one or more, and at the same time, it may be two or less.

[0048] The branched organopolysiloxanes of this disclosure have, on average, one or more carboxyl groups as hydrophilic groups per molecule. In some embodiments, the average number of carboxyl groups contained in one molecule of branched organopolysiloxane may be two or more. There is no particular upper limit to the average number of carboxyl groups contained in one molecule. The average number may be, for example, 16 or less, or 12 or less.

[0049] In some embodiments, the branched organopolysiloxane of the Disclosure may have a refractive index of less than 1.49, or 1.48 or less, or 1.47 or less, or 1.46 or less at a wavelength of 633 nm. Also in some embodiments, the curable composition of the Disclosure, described later, may form a cured product by ultraviolet curing having a refractive index of less than 1.49, or 1.48 or less, or 1.47 or less, or 1.46 or less at a wavelength of 633 nm. Due to this property, the branched organopolysiloxane and the curable composition can be widely applied to various applications requiring low refractive index materials.

[0050] The refractive index can be controlled by the type of substituents on the silicon atoms in the branched organopolysiloxane described above, the number of monovalent organic groups with two hydrophilic groups and UV-curable groups, and the ratio of various siloxane units and OZ groups. For example, the refractive index can be lowered by reducing the number of monovalent organic groups with two hydrophilic groups and UV-curable groups. The refractive index can also be lowered by lowering the ratio of T units and increasing the ratio of M units.

[0051] There are no particular restrictions on the weight-average molecular weight of the branched organopolysiloxane. In some embodiments, the weight-average molecular weight of the branched organopolysiloxane may be 1,000 or more, or 3,000 or more, or 5,000 or more. At the same time, the weight-average molecular weight of the branched organopolysiloxane may be 20,000 or less, or 15,000 or less, or 10,000 or less. If the weight-average molecular weight of the branched organopolysiloxane is within the above range, its alkali solubility is improved, and the applicability of the curable composition containing the branched polyorganosiloxane to the substrate can be improved.

[0052] There are no particular limitations on the polydispersity (hereinafter sometimes referred to as "PDI") of branched organopolysiloxanes. In some embodiments, the polydispersity of the branched polyorganosiloxane may be 1.5 or more and 15 or less. As mentioned above, the higher the weight-average molecular weight, the higher the PDI value tends to be.

[0053] PDI is defined as the value of "Mw / Mn" using the number-average molecular weight (Mn) and weight-average molecular weight (Mw).

[0054] Furthermore, there are no particular restrictions on the softening point and glass transition temperature of the branched polyorganosiloxane. In some embodiments, the glass transition temperature of the branched polyorganosiloxane may be 30°C or higher. If the glass transition temperature is 30°C or higher, the tackiness (adhesion) of the coating surface can be reduced when the curable composition is applied to a substrate to form a coating film. In some embodiments, in addition to the viewpoint of reducing tackiness, considering the usage environment of electronic devices and electrical devices, particularly displays, etc., in which the cured film (film-like cured material) is used, the glass transition temperature may be 60°C or higher, or even 100°C or higher.

[0055] There are no particular restrictions on the method for producing branched organopolysiloxanes. For example, the following methods 1) or 2) can be used for this production: 1) A method of preparing a branched polyorganosiloxane solution comprising a monovalent organic group having two hydrophilic groups and an ultraviolet-curable group by heating a mixture containing a starting material including an alkoxysilane containing two hydrophilic groups (at least one of which is a carboxyl group), an alkoxysilane having an ultraviolet-curable group, and optionally other alkoxysilanes and / or linear siloxanes, a reaction solvent, and an acidic or basic catalyst to carry out a hydrolysis and condensation reaction. 2) A method of preparing a branched polyorganosiloxane solution comprising a monovalent organic group having two hydrophilic groups and an ultraviolet-curable group by adding a basic catalyst and an acid anhydride to a branched polyorganosiloxane solution containing two hydroxyl groups as hydrophilic groups, and carrying out an esterification reaction by heating to convert at least some of the hydroxyl groups into a carboxyl group-containing structure. In the method described in 1) above, if necessary, operations such as removal of by-products such as alcohol and excess water, neutralization, and filtration may be performed at any time.

[0056] Of the two methods described above, method 2) is preferable. Furthermore, since neither of the above methods produces heavy metals such as platinum atoms, these methods have advantages when applied to electronic materials, particularly electronic materials in the semiconductor field.

[0057] The method described in 2) above will now be explained with further specific examples. First, the starting materials, methyltrimethoxysilane and glycidoxypropylmethyldimethoxysilane, are dissolved in methoxy-2-propanol as the reaction solvent, and an aqueous solution of trifluoroacetic acid is added as an acidic catalyst to obtain a mixture. This mixture is heated to carry out a hydrolysis and condensation reaction, and the by-products, methyl alcohol and excess water, are removed to obtain a reaction solution containing a reactive branched polyorganosiloxane. To this reaction solution, the starting material, acryloxypropyltrimethoxysilane, and an aqueous solution of potassium hydroxide as a basic catalyst are added to make the reaction system basic, and then the system is heated to carry out a hydrolysis and condensation reaction, followed by neutralization and filtration to obtain a poly(methylsiloxane / 1,2-dihydroxypropyloxypropylmethylsiloxane / acryloxypropylsiloxane) copolymer (hydroxyl group-containing copolymer). To the hydroxyl group-containing copolymer obtained above, succinic anhydride (acid anhydride) and tetramethylguanidine (basic catalyst) are added, and the mixture is heated to carry out an esterification reaction, thereby obtaining a poly(methylsiloxane / 1-carboxyethylcarbonyloxy-2-hydroxypropyloxypropylmethylsiloxane / acryloxypropylsiloxane) copolymer. The structure and molecular weight of the resulting branched polyorganosiloxane 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, the amount of basic catalyst, and the type and amount of acid anhydride.

[0058] <Curable Composition> The curable composition of this disclosure comprises at least the following components (A), (B), and (C): (A) the branched organopolysiloxane of this disclosure described above, (B) a photopolymerization initiator component in an amount of 0.1 to 10 parts by mass per 100 parts by mass of (A), and (C) an organic solvent.

[0059] Component (B), the photopolymerization initiator, is a component that can function as a catalyst in the curing reaction of component (A) by irradiation with high-energy rays. The type of photopolymerization initiator can be appropriately determined according to the type of UV-curable group that component (A) has. For example, if the UV-curable group of component (A) is an organic group containing a cationic polymerizable functional group such as an epoxy group or a vinyl ether group, a photocationic polymerization initiator is used as the photopolymerization initiator. On the other hand, if the UV-curable group of component (A) is an organic group containing a radical polymerizable functional group such as a (meth)acryloxy group, a photoradical polymerization initiator can be used as the photopolymerization initiator. Note that one type of photopolymerization initiator may be used alone, or multiple types may be used in combination. In some embodiments, the UV-curable group of component (A) is an organic group containing a radical polymerizable functional group, and component (B), the photopolymerization initiator, may be a photoradical polymerization initiator. Photoradical polymerization initiators generate free radicals when irradiated with high-energy rays such as ultraviolet light, which trigger a radical polymerization reaction that can cure the branched organopolysiloxane, which is component (A).

[0060] As a photoradical polymerization initiator, any known type in the art, such as photocleavage type or hydrogen abstraction type, can be arbitrarily selected and used, and is not particularly limited to any specific type. Non-limiting examples of photoradical polymerization initiators include acetophenone, α-hydroxyacetophenone, p-anisyl, benzyl, benzoin, benzophenone, 2-benzoylbenzoic acid, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(dimethylamino)benzophenone, benzoin methyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin ethyl ether, 4-benzoylbenzoic acid, 2, 2'-Bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, methyl 2-benzoyl benzoate, 2-(1,3-benzodioxol-5-yl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-benzyl-2-(dimethylamino)-4'-morpholinobtyrophenone, (±)-camphorquinone, 2-chlorothioxanthone, 4,4'-dichlorobenzophenone, 2,2-diethoxy Examples include cyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,4-diethylthioxanthene-9-one, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl(2,4,6-trimethylbenzoyl)phenylphosphine, 1,4-dibenzoylbenzene, 2-ethylanthraquinone, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methylpropiophenone, 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, 2-isopropylthioxanthone, lithium phenyl(2,4,6-trimethylbenzoyl)phosphine, 2-methyl-4'-(methylthio)-2-morpholinopropiophenone, 2-isonitrosopropiophenone, 2-phenyl-2-(p-toluenesulfonyloxy)acetophenone, and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.Furthermore, commercially available photoradical polymerization initiators include Omnirad® 651, 184, 1173, 2959, 127, 907, 369, 369E, and 379EG (alkylphenone-based photopolymerization initiators, IGM Resins BV), Omnirad® TPO H, TPO-L, and 819 (acylphosphine oxide-based photopolymerization initiators, IGM Resins BV), Omnirad® MBF and 754 (intramolecular hydrogen abstraction type photopolymerization initiators, IGM Resins BV), and Irgacure® OXE01 and OXE02 (oxime ester-based non-polymerization initiators, BASF).

[0061] The content of component (B) in the curable composition is not particularly limited, as long as the desired photopolymerization, i.e., photocuring reaction, occurs. In some embodiments, the content of component (B) in the curable composition may be 0.1 to 10 parts by mass, or 0.5 to 5 parts by mass, per 100 parts by mass of the branched organopolysiloxane which is component (A).

[0062] In some embodiments, a photosensitizer may be used in combination with the above-mentioned photoradical polymerization initiator. The use of a photosensitizer is expected to enhance the photon-quantum efficiency of the polymerization and curing reactions. Non-limiting examples of photosensitizers include anthracene compounds, phenothiazine compounds, perylene compounds, cyanine compounds, merocyanine compounds, coumarin compounds, benzylidene ketone compounds, (thio)xanthene or (thio)xanthone compounds (e.g., isopropylthioxanthone, 2,4-diethylthioxanthone), alkyl-substituted anthracenes, squarium compounds, (thia)pyrillium compounds, porphyrin compounds, and combinations thereof.

[0063] The organic solvent component (C) is a compound that has the function of controlling the applicability of component (A) and adjusting the film thickness of the coating film. In some embodiments, component (C) may be a compound other than benzene, toluene, ethylbenzene, and xylene. In other words, the curable composition does not have to contain benzene, toluene, ethylbenzene, and xylene.

[0064] The organic solvent that can be used as component (C) is not particularly limited, but examples 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, methyl 3-methoxybutyl acetate, methyl-3-methoxybutyl acetate, methyl-3-methoxybutyl propionate, ethyl acetate, n-propyl acetate, i-propyl acetate, n-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, ethyl 2-oxobutanoate, and other esters; alicyclic hydrocarbons such as cyclohexane, methylcyclohexane, ethylcyclohexane, and dimethylcyclohexane; Examples include aromatic ethers such as anisole, phenethole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 3,4-dimethoxytoluene, and 1,4-bis(methoxymethyl)benzene. The organic solvent as component (C) may be used alone, or multiple types may be used in combination, taking into consideration their miscibility with component (A).

[0065] Furthermore, it is preferable not to use compounds containing functional groups that chemically react with the catalyst during the production of component (A) as component (C). In some embodiments, when an acidic catalyst is used during the production of component (A), it is beneficial to choose not to use the above-mentioned "(poly)alkylene glycol monoalkyl ether acetates," "alkyl lactate esters," and "other esters."

[0066] The content of component (C) in the curable composition is not particularly limited and is appropriately set according to the miscibility with (A) branched organopolysiloxane, the viscosity of the curable composition, the thickness of the coating film formed by the composition, etc. Typically, component (C) is used in an amount of 50 to 10,000 parts by mass per 100 parts by mass of component (A). In some embodiments, the content of component (C) in the curable composition may be such that the concentration of component (A) in the curable composition is in the range of 1 to 50% by mass or 2 to 40% by mass.

[0067] In some embodiments, the curable compositions of the present disclosure may optionally contain further additives as components other than the above-described components (A) to (C) and the photosensitizers described above, which may be used optionally (hereinafter referred to as "other components"). Examples of such optionally used other components are, but are not limited to, those listed below.

[0068] In some embodiments, the curable composition may contain an adhesion promoter to improve adhesion to the substrate. When the curable composition is used in applications requiring adhesion to a substrate, such as coatings and sealants, it is preferable to add an adhesion promoter to the curable composition. Any adhesion promoter can be used as this adhesion promoter, as long as it does not significantly hinder the process of removing component (C) from the curable composition. One type of adhesion promoter may be used alone, or multiple types may be used in combination.

[0069] The adhesion-imparting agent is not particularly limited, but examples include: organosilanes having a trialkoxysiloxy group (e.g., trimethoxysiloxy group, triethoxysiloxy group) and / or a 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 with approximately 4 to 20 silicon atoms, having a trialkoxysiloxy group and / or a trialkoxysilylalkyl group and a hydrosilyl group and / or an alkenyl group; organosilanes having a trialkoxysiloxy group and / or a trialkoxysilylalkyl group and a methacryloxyalkyl group (e.g., 3-methacryloxypropyl group); Organosiloxane oligomers having a linear, branched, or cyclic structure with approximately 4 to 20 silicon atoms, comprising a trialkoxysiloxy group and / or a trialkoxysilyl alkyl group and a methacryloxyalkyl group; organosilanes having a trialkoxysiloxy group and / or a trialkoxysilyl alkyl 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 with approximately 4 to 20 silicon atoms, comprising a trialkoxysiloxy group and / or a trialkoxysilyl alkyl group and an epoxy group-bonded alkyl group; organic compounds having two or more trialkoxysilyl groups (e.g., trimethoxylyl group, triethoxysilyl group); reaction products of aminoalkyltrialkoxysilane and epoxy group-bonded alkyltrialkoxysilane; Examples include epoxy group-containing ethyl polysilicate.

[0070] More specifically, the adhesion-imparting agent is not particularly limited, but examples 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) Examples include xysilyl)hexane, 1,3-bis[2-(trimethoxysilyl)ethyl]-1,1,3,3-tetramethyldisiloxane, reaction products of 3-glycidoxypropyltriethoxysilane and 3-aminopropyltriethoxysilane, condensation products of silanol-blocked methylvinylsiloxane oligomer and 3-glycidoxypropyltrimethoxysilane, condensation products of silanol-blocked methylvinylsiloxane oligomer and 3-methacryloxypropyltriethoxysilane, and tris(3-trimethoxysilylpropyl)isocyanurate.

[0071] In some embodiments, when the curable composition contains an adhesion promoter, the amount is not particularly limited, but from the viewpoint of suppressing discoloration of the solid obtained from the composition while sufficiently exhibiting adhesion, the content of the adhesion promoter may be 0.01 parts by mass or more per 100 parts by mass of the branched organopolysiloxane, which is component (A), and at the same time, it may be 5 parts by mass or less, or 2 parts by mass or less.

[0072] Further non-limiting examples of other components include leveling agents, wettability modifiers, silane coupling agents not included in the adhesion-improving agents listed above, high-energy ray absorbers, antioxidants, polymerization inhibitors, fillers (functional fillers such as reinforcing fillers, insulating fillers, hollow fillers, and thermal conductive fillers), and thixotropic agents. These may be used individually or in combination. Thixotropic agents are particularly useful when the curable composition is used as a sealant.

[0073] The method for preparing the curable composition of this disclosure is not particularly limited. For example, the curable composition can be prepared by mixing the various components described above in a known manner.

[0074] The uses of the curable compositions of this disclosure are not particularly limited. In some embodiments, the curable compositions may be used as insulating coating agents, or insulating coatings may be formed using the curable compositions. In another embodiment, a display device may include a layer made of a solid formed using the curable compositions of this disclosure. In this disclosure, the solids and coatings formed using the curable compositions may be in a cured state or an uncured state.

[0075] The processing methods for using the curable compositions of this disclosure in various applications will be described. In some embodiments, the curable compositions of this disclosure are used in various applications by curing them into a cured film (a film-like cured product). The method for obtaining the cured film is not particularly limited as long as it is a method that can cure a film made of the curable composition. As such a method, a known lithography process can be applied to produce a patterned cured film. In some embodiments, a typical method for producing a patterned cured film includes the following steps 1) to 5): 1) applying the curable composition onto a substrate to form a coating film, 2) removing the organic solvent from the obtained coating film, 3) regioselectively exposing the coating film after the organic solvent has been removed, 4) developing the exposed coating film, and 5) heating the developed patterned film to completely cure the film and obtain a patterned cured film.

[0076] The substrate used in step 1) is not particularly limited, and various substrates such as glass substrates, silicon substrates, and glass substrates coated with a transparent conductive film can be used. The method of applying the curable composition onto the substrate in step 1) is not particularly limited, and known methods using coating devices such as spin coaters, roll coaters, bar coaters, and slit coaters can be applied. The method of removing the organic solvent from the coating film in step 2) is not particularly limited. For example, methods include drying on a hot plate at a temperature of 80 to 120°C or 90 to 100°C for 1 to 5 minutes, leaving it at room temperature for several hours, or heating it in a hot air heater or infrared heater for several tens of minutes to several hours. In step 3), position-selective exposure of the coating film is usually performed using known active energy ray light sources, including ultraviolet light sources such as high-pressure mercury lamps, metal halide lamps, and LED lamps, and laser light sources such as excimer lasers, via a photomask. Negative and positive photomasks can be used depending on the characteristics of the curable composition. The energy dose irradiated depends on the composition of the curable composition, but is typically 100 to 1,000 mJ / cm². ２ To that extent. In step 4), development is performed with a developer to form a pattern of the desired shape. As a developer, alkaline aqueous solutions and organic solvents are known, but development with alkaline aqueous solutions is the mainstream. Both aqueous solutions of inorganic bases and aqueous solutions of organic bases can be used as alkaline aqueous solutions. Suitable developers include basic aqueous solutions of sodium hydroxide, potassium hydroxide, sodium carbonate, ammonia, quaternary ammonium salts, etc., with aqueous solutions of tetramethylammonium hydroxide being particularly preferred. The development method is not particularly limited, and for example, the dipping method, spray method, etc. can be applied. In step 5), post-heating (PEB) is performed on the patterned cured film after development. The PEB temperature is not particularly limited as long as thermal decomposition or deformation does not occur in the patterned cured film, but it may be greater than 100°C, or 150 to 250°C, or 150 to 200°C. By performing the above operations, a cured film patterned in the desired shape can be formed.

[0077] In this disclosure, the viscosity of the curable composition and / or the rate of formation of solids formed using the curable composition can be controlled by changing the structure, boiling point, and / or the amount of the organic solvent used as component (C). Furthermore, in this disclosure, the refractive index and mechanical properties of the desired solids can be designed by changing the molecular structure of the branched organopolysiloxane used as component (A) and / or the ratio of the remaining reactive groups (OZ groups). The shape of the solids obtained by removing component (C) from the composition, as disclosed in one embodiment of this disclosure, is not particularly limited and may be a thin film coating or a molded product such as a sheet. In some embodiments, the solids may be used as a sealant or intermediate layer in laminates or display devices. Also, in some embodiments, the solids may be in the form of a thin film coating or a thin film insulating coating. Such insulating coatings are particularly useful, for example, as materials for forming insulating layers that constitute electronic and electrical devices.

[0078] Furthermore, since the solids formed using the curable compositions of this disclosure (in some embodiments, the solids are cured products) have good transparency, insulating coatings made of such solids are suitable as materials for forming insulating layers in display devices such as touch panels and displays. In this case, the insulating layer may form any desired pattern as needed. Therefore, display devices such as touch panels and displays that include an insulating layer made of solids formed using the curable compositions of this disclosure can also be cited as one embodiment of this disclosure.

[0079] The present disclosure will be further described below based on examples, but the present disclosure is not limited to the following examples.

[0080] The synthesis of the branched organopolysiloxanes, the preparation and evaluation of curable compositions, and the preparation and evaluation of cured products thereof will be described in detail with reference to examples.

[0081] <Appearance of curable composition and cured product> The curable composition and cured product (cured product obtained by ultraviolet irradiation, or if curing by ultraviolet irradiation is not possible, cured product obtained by heating) were visually observed and their appearance, including transparency, was determined. <Average unit formula and silanol group content of branched organopolysiloxane> Using biacetone as the solvent １３ C-NMR and ２９ The molar concentrations of each siloxane unit and silanol group were calculated by Si-NMR spectroscopy. The average unit formula and the silanol group content were then identified. <Molecular weight and PDI of branched organopolysiloxane> Gel permeation chromatography (GPC) analysis was performed using tetrahydrofuran as the 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. <UV curability of curable composition> The curable composition was spin-coated onto a silicon wafer as a substrate to a film thickness of 3 μm. The curable composition on the substrate was heated in an oven at 100°C for 5 minutes to form an uncured coating film X that did not contain organic solvents. 365 nm light (ultraviolet light) from an LED light source was applied to this coating film at 1,000 mJ / cm². ２Coating film Y was prepared by irradiating it to an energy dose of . The obtained coating film Y was immersed in methoxy-2-propanol (PGME) for 1 minute, and the appearance of coating film Z after immersion was observed visually. If there is no change in the appearance of the coating film after immersion, it means that the curable composition has cured sufficiently and has excellent UV curability. On the other hand, if the coating film dissolves after immersion, it means that the UV curability of the curable composition is insufficient. A: No change in appearance C: Coating film dissolves <Alkali solubility of branched organopolysiloxane> Coating film X (unirradiated with UV) was prepared in the same manner as in the section on "UV curability of curable composition". This coating film X was immersed together with the substrate in a 2.38 mass% aqueous solution of tetramethylammonium hydroxide (TMAH) at room temperature (25°C) for 1 minute (developed), and then washed with water in a room temperature water bath for 15 seconds. After washing, the substrate surface was observed, and the alkali solubility was determined according to the following criteria (alkali solubility #1). Separately, coating film Y (after UV irradiation) was prepared using the same method as described in the section on "UV curability of curable compositions". This coating film Y was immersed together with the substrate in a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) for 1 minute at room temperature (25°C) (development), and then washed by immersion in a water bath at room temperature for 15 seconds. After washing, the substrate surface was observed and the alkali solubility was determined according to the following criteria (alkali solubility #2). A: Substantially no coating film remains on the substrate (even if some coating film remains, it is less than 5% by area ratio) B: 5-10% of the coating film remains on the substrate by area ratio C: Almost the entire coating film remains on the substrate If the evaluation of alkali solubility #1 is "A" or "B" and the evaluation of alkali solubility #2 is "C", it can be said to be a favorable evaluation. Specifically, with this type of evaluation, branched polyorganosiloxanes that have not been irradiated with ultraviolet light readily dissolve in alkaline aqueous solutions, while branched polyorganosiloxanes that have been irradiated with ultraviolet light harden and become insoluble or sparingly soluble in alkaline aqueous solutions, making it possible to easily produce the desired pattern. <Refractive index of cured product> For coating film Y (after ultraviolet irradiation) prepared by the same method as in the section "Ultraviolet curability of curable composition", the refractive index at a wavelength of 633 nm was measured under the following conditions.In the comparative example composition, which was not cured by UV irradiation, a heat-cured coating film was formed by heating coating film X (unirradiated with UV) at 200°C for 10 minutes using the same method as described in the section on "UV curability of curable compositions," and its refractive index was measured under the same conditions. Measurement device: Metricon Model 2010 / M prism coupler film thickness and refractive index meter. Measurement temperature: 23°C.

[0082] <Synthesis Example 1: Branched Organopolysiloxane (A-1)> In a 200 mL three-necked flask equipped with a thermometer, a stirrer, and a nitrogen inlet tube, 22.5 g of hexamethyldisiloxane, 56.7 g of methyltrimethoxysilane, 20.4 g of glycidoxypropylmethyldimethoxysilane, 30 μL of trifluoromethanesulfonic acid, 25.7 g of water, and 124 g of 1,2-dimethoxyethane (DME) were charged as starting materials and refluxed at 70°C for 1 hour to carry out the hydrolysis and condensation reaction. By raising the heating temperature to 115°C, methanol and excess water were removed from the resulting reaction solution. The reaction solution was then cooled to below 30°C, and 0.5 g of a 34% by mass potassium hydroxide aqueous solution was added to the reaction solution. Next, 32.6 g of acryloxypropyltrimethoxysilane, 3.5 g of water, and 15 g of DME were added to the reaction solution, and the mixture was heated again at 90°C for 30 minutes while removing volatile components to complete the reaction. After cooling the reaction solution to below 30°C, 3.0 g of magnesium sulfate was added, the mixture was stirred for 20 minutes, and the solid was filtered off. Half of the volatile components were removed by distillation under reduced pressure, and the same amount of DME was added. This process was repeated twice to obtain a colorless DME solution of reactive branched organopolysiloxane (a-1; solid content concentration: 40% by mass). １３ C and ２９SiNMR spectroscopy identified the product as a poly(trimethylsiloxane / 1,2-dihydroxypropyloxypropylmethylsiloxane / methylsiloxane / acryloxypropylsiloxane) copolymer (hydroxyl group-containing copolymer). 30 g of (a-1) as the substrate, 0.34 g of tetramethylguanidine, and 1.2 g of succinic anhydride were charged into a 50 mL three-necked flask equipped with a thermometer, stirrer, and nitrogen inlet tube, and the esterification reaction was carried out by heating at 90°C for 2 hours. After cooling the reaction solution to below 30°C, half of the DME was removed by reduced pressure distillation, and the same amount of propylene glycol monomethyl ether (PGME) was added. This procedure was repeated twice to obtain a pale yellow branched organopolysiloxane PGME solution (A-1; solid content: 33% by mass). The obtained (A-1) was then... １３ C and ２９ The material was analyzed by SiNMR spectroscopy and gel permeation chromatography (GPC). The results confirmed that (A-1) is a poly(trimethylsiloxane / 1-carboxyethylcarbonyloxy-2-hydroxypropyloxypropylmethylsilyl / methylsilyl / acryloxypropylsilyl) copolymer with a molar ratio of 30 / 10 / 45 / 15. The OZ group content was 0.06 moles per mole of silicon atoms, and the silanol group content was 0.04 moles per mole of silicon atoms. The Mw was 6,000 and the PDI was 3.0.

[0083] From the above results, branched organopolysiloxane (A-1) has the following average unit formula (1): a=0.3, b=0.1, c=0.6 (0.45 + 0.15), d=0, e1=0.04, e2=0.02, R １ = Methyl group, R Ａ = 1-carboxyethylcarbonyloxy-2-hydroxypropyloxypropyl group (a monovalent organic group having two hydrophilic groups), R Ｂ = Methyl group and acryloxypropyl group (UV-curable group), R ２It was found that it has the following average unit formula, which is a methyl group: [(CH3)3SiO 1 / 2 ] 0.3 [{CH2(OR X )CH(OH)CH2O(CH2)3}(CH3)SiO 2 / 2 ] 0.1 [(CH3)SiO 3 / 2 ] 0.45 [CH2=CH(C=O)O(CH2)3SiO 3 / 2 ] 0.15 [HO 1 / 2 ] 0.04 [(CH3)O 1 / 2 ] 0.02 　 R in the above formula ｘ The compound is -C(=O)-CH2-CH2-CO2H. 　 In addition, (A-1) had an average of 3 UV-curable groups per molecule, an average of 2 monovalent organic groups with 2 hydrophilic groups per molecule, and an average of 2 carboxyl groups per molecule.

[0084] <Synthesis Example 2: Branched Organopolysiloxane (A-2)> The same procedure as in Synthesis Example 1 was followed, except that the amounts of various raw materials were changed to 18.2 g of hexamethyldisiloxane, 55.0 g of methyltrimethoxysilane, 29.6 g of glycidoxypropylmethyldimethoxysilane, 31 μL of trifluoromethanesulfonic acid, 26.7 g of water, 127.0 g of DME, 31.63 g of acryloxypropyltrimethoxysilane, and 0.22 g of 34% by mass of potassium hydroxide aqueous solution. A colorless DME solution of branched organopolysiloxane (a-2) with a solid content of 40% was obtained. １３ C and ２９SiNMR spectroscopy identified the product as a poly(trimethylsiloxane / 1,2-dihydroxypropyloxypropylmethylsiloxane / methylsiloxane / acryloxypropylsiloxane) copolymer (hydroxyl group-containing copolymer). 45 g of (a-2) prepared by the above method, 0.77 g of tetramethylguanidine, and 2.68 g of succinic anhydride were charged, and the same procedure as in Synthesis Example 1 was carried out to obtain a PGME solution of a colorless branched organopolysiloxane (A-2) with a solid content of 33%. Subsequently, analysis using the same method as described above confirmed that (A-2) is a poly(trimethylsiloxane / 1-carboxyethylcarbonyloxy-2-hydroxypropyloxypropylmethylsilyl group / methylsilyl group / acryloxypropylsilyl group) copolymer with a molar ratio of 25 / 15 / 45 / 15. The content of OZ groups was 0.07 moles per mole of silicon atoms, and the content of silanol groups was 0.05 moles per mole of silicon atoms. The Mw was 13,300 and the PDI was 6.0.

[0085] From the above results, branched organopolysiloxane (A-2) has the following average unit formula (1): a = 0.25, b = 0.15, c = 0.6 (0.45 + 0.15), d = 0, e1 = 0.05, e2 = 0.02, R １ = Methyl group, R Ａ = 1-carboxyethylcarbonyloxy-2-hydroxypropyloxypropyl group (a monovalent organic group having two hydrophilic groups), R Ｂ = Methyl group and acryloxypropyl group (UV-curable group), R ２ It was found that it has the following average unit formula, which is a methyl group: [(CH3)3SiO 1 / 2 ] 0.25 [{CH2(OR X )CH(OH)CH2O(CH2)3}(CH3)SiO 2 / 2 ] 0.15 [(CH3)SiO 3 / 2 ] 0.45[CH2=CH(C=O)O(CH2)3SiO 3 / 2 ] 0.15 [HO 1 / 2 ] 0.05 [(CH3)O 1 / 2 ] 0.02 　 R in the above formula ｘ The compound is -C(=O)-CH2-CH2-CO2H. 　 In addition, (A-2) had an average of 3 UV-curable groups per molecule, an average of 3 monovalent organic groups with two hydrophilic groups per molecule, and an average of 3 carboxyl groups per molecule.

[0086] <Synthesis Example 3: Branched Organopolysiloxane (A-3)> (a-1) was prepared in the same manner as in Synthesis Example 1. Then, the same procedure as in Synthesis Example 1 was carried out, except that the amount of (a-1) was changed to 15 g, the amount of tetramethylguanidine to 0.2 g, and the amount of succinic anhydride to 1.20 g, to obtain a PGME solution of a colorless branched organopolysiloxane (A-3) with a solid content of 33%. Subsequently, analysis was performed using the same method as above, and it was confirmed that (A-3) is a poly(trimethylsiloxane / 1,2-di(carboxyethylcarbonyloxy)propyloxypropylmethylsilyl group / methylsilyl group / acryloxypropylsilyl group) copolymer with a molar ratio of 30 / 10 / 45 / 15. Furthermore, the OZ group content was 0.06 moles per mole of silicon atoms, and the silanol group content was 0.04 moles per mole of silicon atoms. The Mw was 6,100, and the PDI was 3.0.

[0087] From the above results, branched organopolysiloxane (A-3) has the following average unit formula (1): a=0.3, b=0.1, c=0.6 (0.45 + 0.15), d=0, e1=0.04, e2=0.02, R １ = Methyl group, R Ａ = 1,2-di(carboxyethylcarbonyloxy)propyloxypropyl group (a monovalent organic group having two hydrophilic groups), RＢ = Methyl group and acryloxypropyl group (UV-curable group), R ２ It was found that it has the following average unit formula, which is a methyl group: [(CH3)3SiO 1 / 2 ] 0.3 [{CH2(OR X )CH(OR X )CH2O(CH2)3}(CH3)SiO 2 / 2 ] 0.1 [(CH3)SiO 3 / 2 ] 0.45 [CH2=CH(C=O)O(CH2)3SiO 3 / 2 ] 0.15 [HO 1 / 2 ] 0.04 [(CH3)O 1 / 2 ] 0.02 　 R in the above formula ｘ This is -C(=O)-CH2-CH2-CO2H. Note that (A-3) had an average of 3 UV-curable groups per molecule, an average of 2 monovalent organic groups with 2 hydrophilic groups per molecule, and an average of 4 carboxyl groups per molecule.

[0088] <Synthesis Example 4: Branched Organopolysiloxane (A-4)> (a-2) was prepared in the same manner as in Synthesis Example 2. Then, the same procedure as in Synthesis Example 2 was carried out, except that the amount of (a-2) was changed to 90 g, the amount of tetramethylguanidine to 3.0 g, and the amount of succinic anhydride to 10.75 g, to obtain a PGME solution of a colorless branched organopolysiloxane (A-4) with a solid content of 33%. Subsequently, analysis was performed using the same method as described above, and it was confirmed that (A-4) is a poly(trimethylsiloxane / 1,2-di(carboxyethylcarbonyloxy)propyloxypropylmethylsilyl group / methylsilyl group / acryloxypropylsilyl group) copolymer with a molar ratio of trimethylsilyl group / 1,2-di(carboxyethylcarbonyloxy)propyloxypropylmethylsiloxane / methylsiloxane / acryloxypropylsiloxane) of 25 / 15 / 45 / 15. Furthermore, the OZ group content was 0.07 moles per mole of silicon atoms, and the silanol group content was 0.05 moles per mole of silicon atoms. The Mw was 13,500, and the PDI was 6.0.

[0089] From the above results, branched organopolysiloxane (A-4) has the following average unit formula (1): a = 0.25, b = 0.15, c = 0.60 (0.45 + 0.15), d = 0, e1 = 0.05, e2 = 0.02, R Ａ = 1,2-di(carboxyethylcarbonyloxy)propyloxypropyl group (a monovalent organic group having two hydrophilic groups), R Ｂ = Methyl group and acryloxypropyl group (UV-curable group), R ２ It was found that it has the following average unit formula, which is a methyl group: [(CH3)3SiO 1 / 2 ] 0.25 [{CH2(OR X )CH(OR X )CH2O(CH2)3}(CH3)SiO 2 / 2 ] 0.15 [(CH3)SiO 3 / 2 ] 0.45 [CH2=CH(C=O)O(CH2)3SiO 3 / 2 ] 0.15 [HO 1 / 2 ] 0.05[(CH3)O 1 / 2 ] 0.02 　 R in the above formula ｘ The compound is -C(=O)-CH2-CH2-CO2H. 　 In addition, (A-4) had an average of 3 UV-curable groups per molecule, an average of 3 monovalent organic groups with two hydrophilic groups per molecule, and an average of 6 carboxyl groups per molecule.

[0090] <Comparative Synthesis Example 1: Branched Organopolysiloxane (a-5)> In a 100 mL three-necked flask equipped with a thermometer, stirrer, and nitrogen inlet tube, 14.8 g of methyltrimethoxysilane, 8.0 g of glycidoxypropylmethyldimethoxysilane, 6 μL of trifluoromethanesulfonic acid, 6.4 g of water, and 21.5 g of PGME were charged as starting materials and refluxed at 70°C for 1 hour to carry out the hydrolysis and condensation reaction. By raising the heating temperature to 115°C, methanol and excess water were removed from the resulting reaction solution. Next, the reaction solution was cooled to below 30°C, and 0.02 g of a 34% by mass potassium hydroxide aqueous solution was added to the reaction solution. 0.8 g of magnesium sulfate was added, and the mixture was stirred for 20 minutes, after which the solid was filtered off. By repeating the operation of removing half of the volatile components under reduced pressure and adding the same amount of PGME twice, a colorless PGME solution of branched organopolysiloxane (a-5) (solid content concentration: 33% by mass) was obtained. Analysis using the same method as above confirmed that (a-5) is a poly(1,2-dihydroxypropyloxypropylmethylsiloxane / methylsiloxane) copolymer with a molar ratio of 1,2-dihydroxypropyloxypropylmethylsilyl group / methylsilyl group of 25 / 75. The content of OZ groups was 0.24 moles per mole of silicon atoms, and the content of silanol groups was 0.20 moles per mole of silicon atoms. The Mw was 2,300 and the PDI was 2.1.

[0091] From the above results, branched organopolysiloxane (a-5) has the following average unit formula (1): a=0, b=0.25, c=0.75, d=0, e1=0.20, e2=0.04, R Ａ = 1,2-dihydroxypropyloxypropyl group, RＢ = Methyl group, R ２ It was found that the average unit formula for the methyl group is as follows: [(CH2OHCH(OH)CH2O(CH2)3(CH3)SiO 2 / 2 ] 0.25 [(CH3)SiO 3 / 2 ] 0.75 [HO 1 / 2 ] 0.20 [(CH3)O 1 / 2 ] 0.04

[0092] <Comparative Synthesis Example 2: Branched Organopolysiloxane (a-6)> A colorless PGME solution of branched organopolysiloxane (a-6) was obtained using the same method as in Comparative Synthesis Example 1, except that 187.5 g of methyltrimethoxysilane, 0.68 g of oxalic acid, 369 g of PGME as the reaction solvent, and 67.5 g of water were placed in a 1000 mL three-necked flask. The obtained branched organopolysiloxane (a-6) was analyzed using the same method as described above, and it was confirmed that (a-6) is polymethylsilsesquioxane. The content of OZ groups was 0.49 moles per mole of silicon atoms, and the content of silanol groups was 0.44 moles per mole of silicon atoms. The Mw was 3,000 and the PDI was 2.6.

[0093] From the above results, branched organopolysiloxane (a-6) has the following average unit formula (1): a=0, b=0, c=1.00, d=0, e1=0.44, e2=0.05, R Ｂ = Methyl group, R ２ It was found that it has the following average unit formula, which is a methyl group: [(CH3)SiO 3 / 2 ] 1.00 [HO 1 / 2 ] 0.44 [(CH3)O 1 / 2 ] 0.05

[0094] <Comparative Synthesis Example 3: Branched Organopolysiloxane (a-7)> In a 100 mL three-necked flask equipped with a thermometer, a stirrer, and a nitrogen inlet tube, 20.0 g of methyltrimethoxysilane, 6 μL of trifluoromethanesulfonic acid, 6.0 g of water, and 24.0 g of PGME were charged as starting materials and refluxed at 70°C for 1 hour to carry out the hydrolysis and condensation reaction. By raising the heating temperature to 115°C, methanol and excess water were removed from the resulting reaction solution. Next, the reaction solution was cooled to below 30°C, and 0.03 g of a 34% by mass potassium hydroxide aqueous solution was added to the reaction solution. After this, 6.0 g of acryloxypropyltrimethoxysilane and 10 g of PGME were added to the reaction solution and heated again at 90°C for 1 hour to complete the reaction. After cooling the reaction solution to below 30°C, 3.0 g of magnesium sulfate was added and stirred for 20 minutes, and the solid was filtered off. By repeating the process of removing half of the volatile components under reduced pressure and adding the same amount of PGME twice, a colorless PGME solution of a branched organopolysiloxane (a-7) with a solid content of 33% was obtained. Analysis using the same method as above confirmed that (a-7) is a poly(methylsiloxane / acryloxypropylsiloxane) copolymer with a molar ratio of methylsilyl groups to acryloxypropylsilyl groups of 85 / 15. The content of OZ groups was 0.20 moles per mole of silicon atoms, and the content of silanol groups was 0.15 moles per mole of silicon atoms. The Mw was 6,000 and the PDI was 3.2.

[0095] From the above results, branched organopolysiloxane (a-7) has the following average unit formula (1): a=0, b=0, c=1.00(0.85+0.15), d=0, e1=0.15, e2=0.05, R Ｂ = Methyl group and acryloxypropyl group (UV-curable group), R ２ It was found that it has the following average unit formula, which is a methyl group: [(CH3)SiO 3 / 2 ] 0.85 [CH2=CH(C=O)O(CH2)3SiO 3 / 2 ] 0.15 [HO 1 / 2 ] 0.15 [(CH3)O 1 / 2 ] 0.05

[0096] <Examples 1-4 and Comparative Examples 1-3> Curable compositions were prepared by mixing (A) branched organopolysiloxane, (B) photopolymerization initiator, and (C) organic solvent in the parts by mass shown in Table 1. Various evaluations were then performed on the above-mentioned items. The results are all shown in Table 1. Note that the parts by mass in Table 1 are the solid content for all components except (C) organic solvent.

[0097] The terms in Table 1 below have the following meanings. (A-1): Branched organopolysiloxane from Synthesis Example 1 (A-1) (A-2): Branched organopolysiloxane from Synthesis Example 2 (A-2) (A-3): Branched organopolysiloxane from Synthesis Example 3 (A-3) (A-4): Branched organopolysiloxane from Synthesis Example 4 (A-4) (a-5): Branched organopolysiloxane from Comparative Synthesis Example 1 (a-5) (a-6): Branched organopolysiloxane from Comparative Synthesis Example 2 (a-6) (a-7): Branched organopolysiloxane from Comparative Synthesis Example 3 (a-7) (B-1): α-hydroxyacetophenone (product name "Omnirad 1173", manufactured by IGM Resins) (C-1): Methoxy-2-propanol (PGME) (A) + (B): Total mass parts of component (A) and component (B)

[0098]

[0099] The curable compositions of this disclosure (Examples 1-4) exhibited good coatability on silicon wafers and formed homogeneous coatings. Furthermore, the resulting coatings had excellent transparency. In Examples 1-4, the coatings before UV irradiation showed high alkali solubility (alkali solubility #1 rated "A" or "B"), while the coatings after UV irradiation showed decreased alkali solubility (alkali solubility #2 rated "C"). In Examples 1-4, the coatings after UV irradiation were insoluble in PGME (UV curability rated "A"), confirming good UV curability. Additionally, in Examples 1-4, the refractive index of the coatings after UV irradiation (cured coatings of branched organopolysiloxane) was low, less than 1.49. On the other hand, in Comparative Examples 1 and 2, UV curability was not demonstrated because the branched organopolysiloxane did not contain UV-curable groups. Furthermore, in Comparative Example 3, since the branched organopolysiloxane did not contain hydrophilic groups including carboxyl groups, alkali solubility was not demonstrated.

[0100] The branched organopolysiloxanes and curable compositions disclosed herein possess excellent UV curability while exhibiting remarkably high alkali solubility. Therefore, particularly when subjected to a development process with an alkaline aqueous solution, they enable simple and highly accurate pattern formation. Furthermore, the branched organopolysiloxanes and cured films obtained using them have the advantage of excellent mechanical strength and transparency. For these reasons, the branched organopolysiloxanes are particularly suitable as materials for forming insulating layers in display devices such as touch panels and displays, especially flexible displays, and are particularly suitable as patterning materials and coating materials.

Claims

1. The following average unit formula (1): [R 1 (CH3)2SiO 1 / 2 a [R A (CH3)SiO 2 / 2 b [R B SiO 3 / 2 c [SiO 4 / 2 d [HO 1 / 2 e1 [R 2 O 1 / 2 e2 (1) (In formula (1), R １ , R Ａ , R Ｂ are each independently a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, a monovalent organic group having two hydrophilic groups, or an ultraviolet curable group, and R ２ is a monovalent hydrocarbon group having 1 to 4 carbon atoms, and a, b, c, d, e1 and e2 are the following conditions: 0 ≦ a ≦ 0.4; 0 ≦ b ≦ 0.5; 0.4 ≦ c < 1; 0 ≦ d ≦ 0.6; 0 ≦ e1 ≦ 0.2; 0 ≦ e2 ≦ 0.2; 0 ≦ e1 + e2 ≦ 0.2; a + b + c + d = 1, a + b > 0. And it has an average of 1 or more monovalent organic groups having two hydrophilic groups per molecule, has an average of 1 or more carboxyl groups as the hydrophilic group per molecule, and has an average of 1 or more ultraviolet curable groups per molecule, a branched organopolysiloxane.)​​​​​​ 2. The branched organopolysiloxane according to claim 1, wherein the ultraviolet-curable group comprises a (meth)acryloxy group.

3. The branched organopolysiloxane according to claim 1, wherein the monovalent organic group having the two hydrophilic groups is an organic group represented by the following formula (2a) or (2b). *-R 3 -CH(OX 2 )CH2OX 1 (2a) (In formula (2a), R ３ X is a divalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, which may contain an oxygen atom. １ , X ２ Each is independently a hydrogen atom or -C(=O)-R ６ -CO ２ H[R ６ (where * is a divalent aliphatic hydrocarbon group having 1 to 4 carbon atoms, and * is a bonding site to a silicon atom.) (In formula (2b), R ４ R is a divalent aliphatic hydrocarbon group having 1 to 3 carbon atoms. ５ X is a hydrogen atom or a methyl group. １ , X ２ (This is equivalent to the above, where n is an integer between 1 and 4, and * represents the bonding site to the silicon atom.) 4. The branched organopolysiloxane according to claim 1, wherein d = 0 in the average unit formula (1).

5. In the above average unit formula (1), R １ , R Ｂ Each of these is independently a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, or an ultraviolet curable group, R Ａ The branched organopolysiloxane according to claim 1, wherein b is a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, a monovalent organic group having two hydrophilic groups, or an ultraviolet curable group, and 0 < b ≤ 0.

5.

6. In the above average unit formula (1), R １ , R Ａ Each of these is independently a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, or an ultraviolet curable group, R Ｂ The branched organopolysiloxane according to claim 1, wherein is a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, a monovalent organic group having two hydrophilic groups, or an ultraviolet curable group.

7. The branched organopolysiloxane according to claim 1, wherein the average number of carboxyl groups contained in each monovalent organic group in the branched organopolysiloxane is one or more, and the average number of monovalent organic groups per molecule is two or more.

8. A curable composition comprising (A) a branched organopolysiloxane according to any one of claims 1 to 7, (B) a photopolymerization initiator, and (C) an organic solvent, wherein the content of component (B) is 0.1 parts by mass or more and 10 parts by mass or less per 100 parts by mass of component (A).

9. An insulating coating agent comprising the curable composition described in claim 8.

10. An insulating coating formed using the curable composition described in claim 8.

11. A method for producing an insulating coating, comprising the step of removing component (C) from the curable composition described in claim 8.

12. A display device comprising a layer made of a solid formed using the curable composition described in claim 8.

Images