Solvent-free siloxane composition and method for producing siloxane compound

Abstract

Provided are: a solvent-free siloxane composition which is solvent-free, has excellent long-term stability, and has a low refractive index of a cured film; a silicone composition containing a siloxane compound having a structural unit derived from formula (1) and a structural unit derived from a specific combination of at least one selected from the group consisting of formulae (2) to (4), wherein the silanol group at the terminal is selected from the group consisting of hexamethyldisilazane, trimethylsilane chloride, trimethylsilyl acetate, N-(trimethylsilyl) diethylamine, N-(trimethylsilyl) diethylamine, N-(trimethylsilyl) diethylamine, N-(trimethylsilyl) diethylamine, N-(trimethylsilyl) diethylamine, N-(trimethylsilyl) diethylamine, N-(trimethylsilyl) the terminal is blocked by at least one of the group consisting of N, N-trimethylsilyl acetamide and N-(trimethylsilyl) dimethylamine, and satisfies conditions 1 and 2; condition 1 is that the refractive index of the cured film is 1.45 or less, and Condition 2 is that the mass ratios of the structural units derived from formulae (1) to (4) with respect to all structural units of the siloxane compound are respectively within a specific range. Si (A1) (A2) a (OR1) 3-a (1), Si (B1) (B2) b (OR2) 3-b (2), Si (C1) 2 (C2) c (OR3) 2-c (3), and Si (D1) (D2) d (OR4) 3-d (4).

Description

[CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the priority of invention patent application "Japanese Patent Application No. 2023-121728" filed with the Japan Patent Office on July 26, 2023, and all contents disclosed in that application are hereby incorporated as a whole into the description of this application. Technical Field

[0001] The present invention relates to a solvent-free silicone composition and a method for producing a silicone compound. Background Art

[0002] Various coating materials such as various lens materials and flattening films are used in solid-state imaging devices such as charge coupled devices (CCDs) and complementary metal-oxide semiconductor (CMOS) image sensors, display substrates, and various anti-reflection films.

[0003] Such coating materials require many properties such as heat resistance, low-temperature processability, etc. in addition to optical properties such as transparency and appropriate refractive index. In addition, depending on the application, alkali solubility is also required. For such requirements, resin compositions containing siloxane compounds are known to be suitable.

[0004] For example, Patent Document 1 discloses a low-refractive-index film-forming composition characterized by containing a silicone resin obtained by hydrolyzing and condensing a mixed raw material containing two or more specific silane compounds. Prior art literature Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2012-203059 Summary of the invention Problem that the invention aims to solve

[0006] However, the low-refractive-index film-forming composition described in Patent Document 1 has a problem that its stability over time is not yet sufficient.

[0007] In addition, the low-refractive-index film-forming composition described in Patent Document 1 contains a solvent. In recent years, solvent-free low-refractive-index film-forming compositions have been required due to environmental issues, and there is room for further improvement. Means used to solve problems

[0008] The present invention is a solvent-free silicone composition, which contains a silicone compound and satisfies the following conditions 1 and 2. The silicone compound has a structural unit derived from the following formula (1) and a structural unit derived from at least one selected from the group consisting of the following formulas (2) to (4), and the terminal silanol group is capped with at least one selected from the group consisting of hexamethyldisilazane, trimethylsilyl chloride, trimethylsilyl acetate, N-(trimethylsilyl)diethylamine, N-trimethylsilylacetamide and N-(trimethylsilyl)dimethylamine. Si(A 1 )(A 2 ) a (OR 1 ) 3-a (1) In formula (1), A 1 represents a monovalent organic group having a free radical polymerizable double bond, A 2 represents an alkyl group or a silyl group, R 1 Represents an alkyl group; multiple R 1 can be the same or different; a is 0 or 1; S(B 1 )(B 2 ) b (OR 2 ) 3-b (2) In formula (2), B 1 represents an alkyl group, B 2 Represents silyl group, R 2 Represents an alkyl group; multiple R 2 can be the same or different; b is 0 or 1; Si(C 1 ) 2 (C 2 ) c (OR 3 ) 2-c (3) In formula (3), C 1 represents an alkyl group, C 2 Represents silyl group, R 3 Represents an alkyl group; two C 1 Can be the same or different, multiple R 3 Can be the same or different; c is 0 or 1; Si(D 1 )(D 2 ) d (OR 4 ) 3-d (4) In formula (4), D 1 represents a fluoroalkyl group having 3 to 13 fluorine atoms, D2 represents an alkyl group, a silyl group or a monovalent organic group having a free radical polymerizable double bond, R 4 Represents an alkyl group; multiple R 4 They can be the same or different, and d is 0 or 1. [Condition 1] The refractive index of the cured film is 1.45 or less. [Condition 2] In the above siloxane compound, the mass ratio of the structural unit derived from the above formula (1) to all the structural units is represented by w. 1 , the mass ratio of the structural unit derived from the above formula (2) is set to w 2 , the mass ratio of the structural unit derived from the above formula (3) is set to w 3 , the mass ratio of the structural unit derived from the above formula (4) is set to w 4 When 1 10~30,w 2 0~90,w 3 0~90,w 4 0~90,w 2 +w 3 +w 4 It is 70 to 90.

[0009] In the solvent-free silicone composition of the present invention, the silicone compound preferably has structural units derived from at least two types selected from the group consisting of the above formulae (2) to (4). Furthermore, the siloxane compound preferably has structural units derived from the above formulae (2) and (3). In addition, the siloxane compound preferably has a mass ratio w of the structural unit derived from the above formula (1). 1 Below 20. Furthermore, the weight average molecular weight of the siloxane compound is preferably 800 to 10,000. The present invention also relates to a method for producing a siloxane compound, comprising the following steps (1), (2) and (3) in sequence. Process (1) A step of reacting the following formula (1) with at least one selected from the group consisting of the following formulas (2) to (4) to prepare a siloxane compound having a silanol group at the end, Si(A 1 )(A 2 ) a (OR 1 ) 3-a (1) In formula (1), A 1 represents a monovalent organic group having a free radical polymerizable double bond, A2 represents an alkyl group or a silyl group, R 1 Represents an alkyl group; multiple R 1 can be the same or different; a is 0 or 1; Si(B 1 )(B 2 ) b (OR 2 ) 3-b (2) In formula (2), B 1 represents an alkyl group, B 2 Represents silyl group, R 2 Represents an alkyl group; multiple R 2 can be the same or different; b is 0 or 1; Si(C 1 ) 2 (C 2 ) c (OR 3 ) 2-c (3) In formula (3), C 1 represents an alkyl group, C 2 Represents silyl group, R 3 Represents an alkyl group; two C 1 Can be the same or different, multiple R 3 Can be the same or different; c is 0 or 1; Si(D 1 )(D 2 ) d (OR 4 ) 3-d (4) In formula (4), D 1 represents a fluoroalkyl group having 3 to 13 fluorine atoms, D 2 represents an alkyl group, a silyl group or a monovalent organic group having a free radical polymerizable double bond, R 4 Represents an alkyl group; multiple R 4 They can be the same or different, and d is 0 or 1. Process (2) After the addition of the amide compound, the orthoester is dehydrated and the solvent is distilled off. Process (3) A step of dissolving the above-mentioned siloxane compound having a silanol group at the terminal (also referred to as "siloxane compound containing a terminal silanol group") in an organic solvent and then adding at least one selected from the group consisting of hexamethyldisilazane, trimethylsilyl chloride, trimethylsilyl acetate, N-(trimethylsilyl)diethylamine, N-trimethylsilylacetamide and N-(trimethylsilyl)dimethylamine to obtain a blocked siloxane compound. Effects of the Invention

[0010] The present invention can provide a solvent-free silicone composition which is excellent in stability over time and has a low refractive index of a cured film. DETAILED DESCRIPTION

[0011] The solvent-free silicone composition of the present invention comprises a silicone compound and satisfies the following conditions 1 and 2. The silicone compound has a structural unit derived from the following formula (1) and a structural unit derived from at least one selected from the group consisting of the following formulas (2) to (4), and the terminal silanol group is blocked with at least one selected from the group consisting of hexamethyldisilazane, trimethylsilyl chloride, trimethylsilyl acetate, N-(trimethylsilyl)diethylamine, N-trimethylsilylacetamide and N-(trimethylsilyl)dimethylamine. Si(A 1 )(A 2 ) a (OR 1 ) 3-a (1) In formula (1), A 1 represents a monovalent organic group having a free radical polymerizable double bond, A 2 represents an alkyl group or a silyl group, R 1 Represents an alkyl group; multiple R 1 can be the same or different; a is 0 or 1; Si(B 1 )(B 2 ) b (OR 2 ) 3-b (2) In formula (2), B 1 represents an alkyl group, B 2 Represents silyl group, R 2 Represents an alkyl group; multiple R 2 can be the same or different; b is 0 or 1; Si(C 1 ) 2 (C 2 ) c (OR 3 ) 2-c (3) In formula (3), C 1 represents an alkyl group, C 2 Represents silyl group, R 3 Represents an alkyl group; two C 1 Can be the same or different, multiple R 3 Can be the same or different; c is 0 or 1; Si(D 1 )(D2 ) d (OR 4 ) 3-d (4) In formula (4), D 1 represents a fluoroalkyl group having 3 to 13 fluorine atoms, D 2 represents an alkyl group, a silyl group or a monovalent organic group having a free radical polymerizable double bond, R 4 Represents an alkyl group; multiple R 4 They can be the same or different, and d is 0 or 1. [Condition 1] The refractive index of the cured film is 1.45 or less. [Condition 2] In the above siloxane compound, the mass ratio of the structural unit derived from the above formula (1) to all the structural units is represented by w. 1 , the mass ratio of the structural unit derived from the above formula (2) is set to w 2 , the mass ratio of the structural unit derived from the above formula (3) is set to w 3 , the mass ratio of the structural unit derived from the above formula (4) is set to w 4 When 1 10~30,w 2 0~90,w 3 0~90,w 4 0~90,w 2 +w 3 +w 4 It is 70 to 90.

[0012] (Siloxane compound) The solvent-free silicone composition of the present invention contains a silicone compound. First, equation (1) will be described. Si(A 1 )(A 2 ) a (OR 1 ) 3-a (1) In formula (1), A 1 represents a monovalent organic group having a free radical polymerizable double bond, A 2 represents an alkyl group or a silyl group, R 1 Represents an alkyl group; multiple R 1 can be the same or different; a is 0 or 1;

[0014] In the above formula (1), A 1 A monovalent organic group having a vinyl group, an allyl group or a (meth)acryloyl group is preferred.

[0015] In the above general formula (1), A 2 An alkyl group having 1 to 10 carbon atoms is preferred. Examples of such an alkyl group include methyl, ethyl, propyl, isopropyl, tert-butyl, n-butyl and sec-butyl.

[0016] In the above general formula (1), R 1 An alkyl group having 1 to 10 carbon atoms is preferred. Examples of such an alkyl group include methyl, ethyl, propyl, isopropyl, tert-butyl, n-butyl and sec-butyl.

[0017] In the above general formula (1), a is preferably 0.

[0018] Examples of the general formula (1) include vinyl silane compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, methylvinyldimethoxysilane, and methylvinyldiethoxysilane; 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropylethyldiethoxysilane, and 3-(meth)acryloxypropyltriethoxysilane; and allylsilane compounds such as allyltrimethoxysilane and allyltriethoxysilane.

[0019] Next, equation (2) will be described.

[0020] Si(B 1 )(B 2 ) b (OR 2 ) 3-b (2) In formula (2), B 1 represents an alkyl group, B 2 Represents silyl group, R 2 Represents an alkyl group; multiple R 2 can be the same or different; b is 0 or 1;

[0021] In the above formula (2), B 1 An alkyl group having 1 to 10 carbon atoms is preferred. Examples of such an alkyl group include methyl, ethyl, propyl, isopropyl, tert-butyl, n-butyl and sec-butyl.

[0022] In the above formula (2), B 2 It is a siloxy group.

[0023] In the above formula (2), R 2 An alkyl group having 1 to 10 carbon atoms is preferred. Examples of such an alkyl group include methyl, ethyl, propyl, isopropyl, tert-butyl, n-butyl and sec-butyl.

[0024] In the above formula (2), b is preferably 0.

[0025] Examples of the above formula (2) include methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriisopropoxysilane, methyltri-n-butoxysilane, methyltri-tert-butoxysilane, methyltri-sec-butoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, pentyltrimethoxysilane, hexyltrimethoxysilane, dimethyldimethoxysilane, and dimethyldiethoxysilane.

[0026] Next, equation (3) will be described.

[0027] Si(C 1 ) 2 (C 2 ) c (OR 3 ) 2-c (3) In formula (3), C 1 represents an alkyl group, C 2 Represents silyl group, R 3 Represents an alkyl group; two C 1 Can be the same or different, multiple R 3 Can be the same or different; c is 0 or 1;

[0028] In the above formula (3), C 1 An alkyl group having 1 to 10 carbon atoms is preferred. Examples of such an alkyl group include methyl, ethyl, propyl, isopropyl, tert-butyl, n-butyl and sec-butyl.

[0029] In the above formula (3), C 2 It is a siloxy group.

[0030] In the above formula (3), R 3 An alkyl group having 1 to 10 carbon atoms is preferred. Examples of such an alkyl group include methyl, ethyl, propyl, isopropyl, tert-butyl, n-butyl and sec-butyl.

[0031] In the above formula (3), c is preferably 0.

[0032] Examples of the above formula (3) include dimethyldimethoxysilane and dimethyldiethoxysilane.

[0033] The formula (4) is described below.

[0034] Si(D 1 )(D 2 ) d(OR 4 ) 3-d (4) In formula (4), D 1 represents a fluoroalkyl group having 3 to 13 fluorine atoms, D 2 represents an alkyl group, a silyl group or a monovalent organic group having a free radical polymerizable double bond, R 4 Represents an alkyl group; multiple R 4 They can be the same or different, and d is 0 or 1.

[0035] In the above formula (4), D 1 The solvent-free silicone composition can be appropriately selected according to the application of the coating film. For example, in order to make the refractive index smaller, the number of fluorine is preferably selected within the range of 9 to 13. In addition, for example, in order to maintain hardness and reduce the refractive index, the number of fluorine is preferably selected within the range of 3 to 5.

[0036] In the above formula (4), D 2 An alkyl group having 1 to 10 carbon atoms is preferred. Examples of such an alkyl group include methyl, ethyl, propyl, isopropyl, tert-butyl, n-butyl and sec-butyl.

[0037] In the above formula (4), R 4 An alkyl group having 1 to 10 carbon atoms is preferred. Examples of such an alkyl group include methyl, ethyl, propyl, isopropyl, tert-butyl, n-butyl and sec-butyl.

[0038] In the above formula (4), d is preferably 0.

[0039] Examples of the above formula (4) include trifluoropropylmethyldimethoxysilane, trifluoropropylmethyldiethoxysilane, trifluoropropylmethyldipropoxysilane, trifluoropropylmethyldiisopropoxysilane, trifluoropropylethyldimethoxysilane, trifluoropropylethyldiethoxysilane, heptadecafluorodecylmethyldimethoxysilane, tridecafluorooctylmethyldimethoxysilane, tridecafluorooctylmethyldiethoxysilane, tridecafluorooctylmethyldipropoxysilane, tridecafluorooctylmethyldiisopropoxysilane, trifluoropropylvinyldimethoxysilane, trifluoropropylvinyldiethoxysilane, and trifluoropropyltrialkoxysilane.

[0040] In the above siloxane compound, the mass ratio of the structural unit derived from the above formula (1) to all the structural units is represented by w. 1 , the mass ratio of the structural unit derived from the above formula (2) is set to w 2 , the mass ratio of the structural unit derived from the above formula (3) is set to w 3, the mass ratio of the structural unit derived from the above formula (4) is set to w 4 When 1 10~30,w 2 0~90,w 3 0~90,w 4 0~90,w 2 +w 3 +w 4 It is 70 to 90. In addition, the mass ratio of the structural units derived from the above general formulae (1) to (4) can be determined by using 29 Si-NMR and 1 The H-NMR is obtained by measuring the above-mentioned siloxane compound.

[0041] For the above siloxane compound, the mass ratio w of the structural unit derived from formula (1) is 1 It is preferably 20 or less, and more preferably 15 or less.

[0042] The siloxane compound preferably has structural units derived from at least two selected from the group consisting of the above formulae (2) to (4), and more preferably has structural units derived from the above formulae (2) and (3), from the viewpoint of reducing the viscosity of the siloxane composition of the present invention. From the viewpoint of environmental load, it is preferred that the structural unit derived from the above formula (4) is not contained.

[0043] For the above siloxane compound, the mass ratio w of the structural unit derived from formula (2) is 2 It is preferably 0-90, more preferably 30-80.

[0044] For the above siloxane compound, the mass ratio w of the structural unit derived from formula (3) is 3 It is preferably 0-90, more preferably 5-30.

[0045] For the above siloxane compound, the mass ratio w of the structural unit derived from formula (4) is 2 It is preferably 50 or less, more preferably 10 or less, and further preferably 0 from the viewpoint of environmental load.

[0046] The weight average molecular weight (Mw) of the siloxane compound is preferably 800 to 10000. If the weight average molecular weight (Mw) is less than 800, the film-forming property and curing property of the solvent-free siloxane composition may be reduced. If the weight average molecular weight (Mw) exceeds 10000, the viscosity tends to increase. The weight average molecular weight (Mw) of the siloxane compound is more preferably 1,500 to 2,500, and even more preferably 1,800 to 2,400.

[0047] The weight average molecular weight (Mw) can be measured by dissolving the siloxane compound to prepare a solution of 0.02 parts by mass, passing the solution through a filter (manufactured by GL Sciences Inc., GL chromatographic disk, aqueous 25A, pore size 0.2 μm), and then measuring the solution under the following conditions using alliance (manufactured by Waters Japan Ltd.) comprising a size exclusion chromatograph and a refractive index detector. Column: pLgel mixed D (manufactured by Agilent) × 2 connected in series Detector: alliance (manufactured by Waters Corporation, Japan) Eluent: Tetrahydrofuran (THF) Flow rate: 1.0ml / min Injection volume: 100 μl

[0048] (Method for producing siloxane compound) The present invention also relates to a method for producing a siloxane compound obtained by the following steps (1) to (3). Process (1) A step of reacting the following formula (1) with at least one selected from the group consisting of the following formulas (2) to (4) to prepare a siloxane compound having a silanol group at the end, Si(A 1 )(A 2 ) a (OR 1 ) 3-a (1) In formula (1), A 1 represents a monovalent organic group having a free radical polymerizable double bond, A 2 represents an alkyl group or a silyl group, R 1 Represents an alkyl group; multiple R 1 can be the same or different; a is 0 or 1; Si(B 1 )(B 2 ) b (OR 2 ) 3-b (2) In formula (2), B 1 represents an alkyl group, B 2 Represents silyl group, R 2 Represents an alkyl group; multiple R 2 can be the same or different; b is 0 or 1; Si(C 1 ) 2 (C 2 ) c (OR3 ) 2-c (3) In formula (3), C 1 represents an alkyl group, C 2 Represents silyl group, R 3 Represents an alkyl group; two C 1 Can be the same or different, multiple R 3 Can be the same or different; c is 0 or 1; Si(D 1 )(D 2 ) d (OR 4 ) 3-d (4) In formula (4), D 1 represents a fluoroalkyl group having 3 to 13 fluorine atoms, D 2 represents an alkyl group, a silyl group or a monovalent organic group having a free radical polymerizable double bond, R 4 Represents an alkyl group; multiple R 4 They can be the same or different, and d is 0 or 1. Process (2) After the amide compound is added, the orthoester is dehydrated and the solvent is distilled off. Process (3) A step of dissolving the terminal silanol group-containing siloxane compound in an organic solvent and then adding at least one selected from the group consisting of hexamethyldisilazane, trimethylsilyl chloride, trimethylsilyl acetate, N-(trimethylsilyl)diethylamine, N-trimethylsilylacetamide and N-(trimethylsilyl)dimethylamine to obtain a blocked siloxane compound.

[0049] By using the method for producing a siloxane compound of the present invention, the amount of protective reagent (at least one selected from the group consisting of hexamethyldisilazane, trimethylsilyl chloride, trimethylsilyl acetate, N-(trimethylsilyl)diethylamine, N-trimethylsilylacetamide and N-(trimethylsilyl)dimethylamine) used can be reduced, and a solvent-free siloxane compound with excellent temporal stability can be produced economically and stably.

[0050] The step (1) is a step of reacting the formula (1) with at least one selected from the group consisting of the formulas (2) to (4) to prepare a siloxane compound having a silanol group at the terminal.

[0051] As the above formulae (1) to (4), the formulae (1) to (4) described in the above siloxane compounds can be used.

[0052] In the step (1), for example, a method in which a polymerization catalyst is added to a solution prepared by dissolving the general formulas (1) to (4) in an organic solvent in a suitable container and the reaction is carried out while refluxing.

[0053] Preferred examples of the organic solvent include lower alcohols such as ethanol, n-propanol, and isopropanol, ketone compounds such as acetone and methyl ethyl ketone, and ester compounds such as ethyl acetate and n-propyl acetate. Among them, lower alcohols are more preferred, and ethanol and isopropanol are even more preferred from the viewpoint of being able to maintain an appropriate reaction temperature and being easily distilled off.

[0054] As the polymerization catalyst, for example, an acid catalyst such as acetic acid, hydrochloric acid, or p-toluenesulfonic acid monohydrate; or a base catalyst such as ammonia, triethylamine, cyclohexylamine, or tetramethylammonium hydroxide may be used.

[0055] The amount of the polymerization catalyst is preferably such that the number of molecules of the polymerization catalyst is about 0.05 to 0.2 times the total number of molecules of the above formulas (1) to (4).

[0056] The reaction temperature is preferably 60 to 80° C., and the reaction time is preferably about 2 to 24 hours so that the reaction proceeds sufficiently.

[0057] The step (2) is a step in which an amide compound is added after the step (1) and then dehydration using the orthoester and solvent evaporation are performed. The step (2) can stabilize the terminal silanol group.

[0058] Examples of the amide compounds include N,N-dimethylacetamide and N,N-dimethylformamide.

[0059] The amount of the amide compound added is about 15 to 30% by mass based on the total mass of the siloxane compound.

[0060] It is preferred to stir after adding the amide compound. The stirring temperature at this time is preferably 10 to 40° C., and the stirring is preferably performed for 0.5 to 1 hour.

[0061] Examples of the orthoester include triethyl orthoacetate, trimethyl orthoformate, and triethyl orthoformate. By using the above-mentioned orthoester, water generated by the reaction can be removed. When the orthoester is added dropwise, it is preferred that the temperature be not higher than 30° C. from the viewpoint of preventing a side reaction.

[0062] The method for distilling off the solvent is not particularly limited, and a known method can be used, for example, distillation under reduced pressure.

[0063] The siloxane compound containing a terminal silanol group can be stabilized by the reaction between the siloxane compound and the amide compound.

[0064] The step (3) is a step of dissolving the terminal silanol group-containing siloxane compound in an organic solvent, and then adding at least one selected from the group consisting of hexamethyldisilazane, trimethylsilyl chloride, trimethylsilyl acetate, N-(trimethylsilyl)diethylamine, N-trimethylsilylacetamide and N-(trimethylsilyl)dimethylamine in addition to at least one selected from the group consisting of acids, acid anhydrides, acid chlorides and esters, to obtain a blocked siloxane compound.

[0065] As the organic solvent, the organic solvents described in the above step (1) can be appropriately selected.

[0066] In the above step (3), it is preferred that the end-capping agent is added after adding at least one selected from the group consisting of an acid, an acid anhydride, an acid chloride and an ester. Examples of the acid, acid anhydride, acid chloride and ester include acetic anhydride, acetic acid, succinic acid and the like.

[0067] The amount of at least one selected from the group consisting of the acid, the acid anhydride, the acid chloride and the ester added is about 50 to 100% by mass based on the total mass of the protecting agent. This makes it possible to remove ammonia incidentally generated when the terminal is blocked with the above-mentioned protecting agent. In addition, the step of adding at least one selected from the above-mentioned acid, acid anhydride, acid chloride and ester may be omitted because ammonia is not incidentally generated depending on the type of the above-mentioned protecting agent.

[0068] Examples of the protecting agent include at least one selected from the group consisting of hexamethyldisilazane, trimethylsilyl chloride, trimethylsilyl acetate, N-(trimethylsilyl)diethylamine, N-trimethylsilylacetamide, and N-(trimethylsilyl)dimethylamine. Among them, hexamethyldisilazane is preferred from the viewpoint of cost. The amount of the protective agent added is preferably 70 to 150% by mass, more preferably 80 to 100% by mass, based on the total mass of the siloxane compound.

[0069] In the above step (3), the reaction temperature is preferably 10 to 50° C. from the viewpoint of preventing a side reaction.

[0070] In the above step (3), the reaction time is preferably about 3 to 15 hours in order to allow the reaction to proceed sufficiently.

[0071] After the above step (3), it is preferred to remove by-products and residues, and to distill off the organic solvent and water.

[0072] As a method for removing the above-mentioned by-products and residues, a known method can be used. For example, the by-products and residues can be removed by neutralization or mixing with water.

[0073] The organic solvent and water can be evaporated by a known method, for example, water can be removed by sodium sulfate, and the solvent can be evaporated by drying under reduced pressure.

[0074] By distilling off the organic solvent and water, a solvent-free siloxane compound can be obtained.

[0075] (Solvent-free silicone composition) The solvent-free silicone composition of the present invention will be described. In this specification, the term "solvent-free type" means that the mass loss under reduced pressure (5 hPa or less) at 160°C for 2 hours is less than 1%.

[0076] The solvent-free silicone composition of the present invention may contain a leveling agent.

[0077] Examples of the leveling agent include silicone-based surfactants and fluorine-based surfactants. Among them, silicone surfactants are more suitable as the leveling agent of the present invention.

[0078] The content of the leveling agent is preferably 0.05 to 1 part by mass relative to 100 parts by mass of the siloxane compound.

[0079] The solvent-free silicone composition of the present invention may contain a photopolymerizable compound.

[0080] As the photopolymerizable compound, a photopolymerizable compound having a radical polymerizable unsaturated double bond is preferred.

[0081] Examples of the photopolymerizable compound having two or more free radical polymerizable unsaturated double bonds include ester compounds of divalent or more hydroxyl-containing compounds and (meth)acrylic acid, such as 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, and the like. Ester, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetrapropylene glycol di(meth)acrylate, bisphenol A di(meth)acrylate, tri(2-hydroxyethyl)isocyanuric acid di(meth)acrylate, trimethylolpropane tri(meth)acrylate, glycerol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, tri(2-hydroxyethyl)isocyanuric acid tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and the like.

[0082] Among them, from the viewpoint of being able to increase the crosslinking density and impart excellent hardness to the cured film, compounds having a reactive functional group having three or more functions are preferred, for example, trimethylolpropane tri(meth)acrylate, glycerol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, tris(2-hydroxyethyl)isocyanuric acid tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate are preferred, and tris(2-hydroxyethyl)isocyanuric acid tri(meth)acrylate and dipentaerythritol hexa(meth)acrylate are more preferred.

[0083] It is preferred that the photopolymerizable compound is contained in an amount of 10 to 50 parts by mass based on 100 parts by mass of the siloxane compound. If the content of the photopolymerizable compound is less than 10 parts by mass relative to 100 parts by mass of the siloxane compound, the curability of the cured coating and its adhesion to the light-transmitting substrate and the ITO electrode may sometimes become insufficient; if the content of the photopolymerizable compound is more than 50 parts by mass relative to 100 parts by mass of the siloxane compound, the solubility of the uncured coating in the developer may sometimes become insufficient.

[0084] The solvent-free silicone composition of the present invention may contain a polymerization initiator.

[0085] As the polymerization initiator, it is preferable to use a polymerization initiator that can obtain a sufficient photocuring reaction when forming a cured film.

[0086] Examples of the polymerization initiator include benzyl, benzoin, benzophenone, camphorquinone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-hydroxycyclohexylphenylketone, 2,2-dimethoxy-2-phenylacetophenone, 2-methyl-[4'-(methylthio)phenyl]-2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butane-1-one, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)- carbonyl compounds such as 1,3-bis(trichloromethyl)-5-(2'-chlorophenyl)-1,3,5-triazine and 2-[2-(2-furyl)vinyl]-4,6-bis(trichloromethyl)-1,3,5-triazine; imidazole dimers such as 2,2'-bis(2-chlorophenyl)4,5,4',5'-tetraphenyl 1,2'-biimidazole; thioxanthone compounds such as 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, and biguanide compounds such as 1,2-diisopropyl-3-[bis(dimethylamino)methylene]guanidinium=2-(3-benzoylphenyl)propionate; and the like.

[0087] These polymerization initiators may be used alone or in combination of two or more, and may be combined with any photosensitizer. Furthermore, a photoacid generator or a photobase generator may be used in combination as a catalyst for accelerating the condensation reaction of the siloxane compound.

[0088] When the total amount of the siloxane compound and the photopolymerizable compound is 100 parts by mass, it is preferred that the polymerization initiator be contained in an amount of 0.5 to 40 parts by mass.

[0089] If the content of the polymerization initiator is less than 0.5 parts by mass, the photopolymerizability may be reduced and unreacted components may remain in the exposed portion by photolithography. If the content of the polymerization initiator exceeds 40 parts by mass, the storage stability of the solvent-free siloxane composition may be reduced. The amount of the polymerization initiator is more preferably 1 to 20 parts by mass, based on 100 parts by mass of the total amount of the siloxane compound and the polymerizable monomer having two or more radically polymerizable unsaturated double bonds.

[0090] (Other materials) The solvent-free silicone composition of the present invention may be added with the following substances within the range that does not reduce the effect of the present invention: chelate compounds of metals such as aluminum, zirconium, and titanium; cross-linking agents such as carbodiimides, isocyanates, and cross-linking functional groups having epoxy groups or thiol groups; surfactants such as silicones and fluorine groups; photosensitizers such as aromatic hydrocarbons, amino compounds, nitro compounds, quinones, and xanthones; polymerization inhibitors such as hydroquinone, p-methoxyphenol, hindered amines, hindered phenols, di-tert-butylhydroquinone, 4-methoxyphenol, 2,6-di-tert-butyl-p-cresol, and nitrosamine salts; fillers such as inorganic metal oxides and organic microparticles; and the like.

[0091] (Method for producing solvent-free silicone composition) The method for producing the solvent-free siloxane composition of the present invention may be as follows: an organic solvent is placed in a suitable container, and the siloxane compound, the photopolymerizable compound having two or more free radical polymerizable unsaturated double bonds, the polymerization initiator, and other materials are added and mixed while stirring the mixture using a high-speed stirrer or the like. The method for producing the solvent-free silicone composition of the present invention is not limited to the above method, and the order of adding the materials may be arbitrary. In addition, if the solid material is soluble in the organic solvent, the solid material can be dissolved before being put in; if the solid material can be dispersed in the organic solvent directly or using a dispersant, the solid material can be dispersed before being put in.

[0092] (Method for forming a cured film) The method for forming a cured film using the solvent-free silicone composition of the present invention preferably includes: a coating step of coating the solvent-free silicone composition on a substrate; an exposure step of irradiating an exposed portion with active energy rays to form a cured film; and a development step of dissolving and removing the coating liquid in the unexposed portion with a developer. In addition, after the above-mentioned coating step, thermal curing may be performed.

[0093] The coating method in the coating step, the active energy rays for irradiating the exposed portion in the exposure step and the irradiation method, and the developer for removing the coating solution in the exposed portion can be appropriately selected from active energy rays, developers and methods used in conventional photolithography.

[0094] For example, the solvent-free siloxane composition is diluted to a nonvolatile content of 20 mass %, applied using a spin coater, heated (pre-baked) at 80° C. for 3 minutes, and then irradiated with a mask aligner at 100 mJ / cm 2The test pattern is printed (engraved) under irradiation conditions, immersed in a developer for 1 minute, and then heated (post-baked) at 150° C. for 30 minutes, thereby obtaining a cured film. As the pre-baking conditions, it is preferable to perform the treatment at 60 to 130° C. for 1 to 3 minutes. The irradiation conditions are preferably 50 to 260 mJ / cm 2 . As the post-baking conditions, it is preferable to perform the treatment at 120 to 230° C. for 30 to 60 minutes.

[0095] The thermal curing can be performed by, for example, performing a heating treatment at 130° C. for 10 minutes and then performing a heating treatment at 180° C. for 60 minutes.

[0096] (Physical properties of solvent-free silicone composition) The solvent-free silicone composition of the present invention is excellent in stability over time.

[0097] In this specification, the temporal stability was evaluated by the following method.

[0098] The viscosity and weight average molecular weight of the solvent-free silicone composition immediately after preparation and after storage at 40° C. for one week were compared. When the increase in viscosity and weight average molecular weight was less than 15%, it was judged that the stability over time was excellent. The viscosity was measured using an R115 type viscometer RE-105L (E type viscometer, manufactured by Toki Sangyo Co., Ltd.) (measurement temperature: 25° C.), and the weight average molecular weight was measured by the above-mentioned method.

[0099] The refractive index of the cured film of the solvent-free silicone composition of the present invention is 1.45 or less.

[0100] The refractive index of the cured film is measured by the following method. The siloxane compound and 5% by mass of a polymerization initiator (Omnirad 184, manufactured by TIANJIN NEW MATERIALS) based on the siloxane compound were dissolved in tetrahydrofuran (THF), and the tetrahydrofuran was removed by reduced pressure distillation to prepare a solvent-free siloxane composition. Next, 1.5 g of the solvent-free siloxane composition was applied onto a glass substrate by spin coating at 3000 rpm for 60 seconds, and then placed in a plastic bag, and the air inside was replaced with nitrogen gas to obtain a cumulative light intensity of 3000 mJ / cm 2 The 365nm UV light is irradiated to form a cured film. Finally, the refractive index of the cured film at a wavelength of 550 nm was measured using a microspectroscopic film thickness meter OPTM series (manufactured by Otsuka Electronics Co., Ltd.). The film thickness of the cured film can also be measured using a microspectroscopic film thickness meter OPTM series (manufactured by Otsuka Electronics Co., Ltd.). This specification discloses the following technical solutions.

[0101] The present disclosure (1) is a solvent-free silicone composition comprising a silicone compound and satisfying the following conditions 1 and 2, wherein the silicone compound has a structural unit derived from the above formula (1) and a structural unit derived from at least one selected from the group consisting of the above formulas (2) to (4), and the terminal silanol group is capped with at least one selected from the group consisting of hexamethyldisilazane, trimethylsilyl chloride, trimethylsilyl acetate, N-(trimethylsilyl)diethylamine, N-trimethylsilylacetamide and N-(trimethylsilyl)dimethylamine. [Condition 1] The refractive index of the cured film is 1.45 or less. [Condition 2] In the above siloxane compound, the mass ratio of the structural unit derived from the above formula (1) to all the structural units is represented by w. 1 , the mass ratio of the structural unit derived from the above formula (2) is set to w 2 , the mass ratio of the structural unit derived from the above formula (3) is set to w 3 , the mass ratio of the structural unit derived from the above formula (4) is set to w 4 When 1 10~30,w 2 0~90,w 3 0~90,w 4 0~90,w 2 +w 3 +w 4 It is 70 to 90. The present disclosure (2) is the solvent-free siloxane composition according to the present disclosure (1), wherein the siloxane compound has structural units derived from at least two selected from the group consisting of the above formulae (2) to (4). The present disclosure (3) is the solvent-free siloxane composition according to the present disclosure (1) or (2), wherein the siloxane compound has structural units derived from the above formulae (2) and (3). The present disclosure (4) is the solvent-free siloxane composition according to any one of the present disclosures (1) to (3), wherein the mass ratio w of the structural unit derived from the above formula (1) of the above siloxane compound is 1 Below 20. The present disclosure (5) is the solvent-free siloxane composition according to any one of the present disclosures (1) to (4), wherein the weight average molecular weight of the siloxane compound is 800 to 10,000. The present disclosure (6) is also a method for producing a siloxane compound, which comprises the following steps (1), (2) and (3) in sequence. Process (1) A step of reacting the above formula (1) with at least one selected from the group consisting of the above formulas (2) to (4) to prepare a siloxane compound having a silanol group at the terminal. Process (2) After the amide compound is added, a dehydration and solvent distillation step is performed. Process (3) A step of dissolving the terminal silanol group-containing siloxane compound in an organic solvent and then adding at least one selected from the group consisting of hexamethyldisilazane, trimethylsilyl chloride, trimethylsilyl acetate, N-(trimethylsilyl)diethylamine, N-trimethylsilylacetamide and N-(trimethylsilyl)dimethylamine to obtain a blocked siloxane compound. Example

[0102] The present invention is further described in detail below by way of examples, but the present invention is not limited to these examples. In addition, unless otherwise specified, "%" means "mass %", and "part" means "mass part".

[0103] The materials used in Examples and Comparative Examples are as follows.

[0104] (Compound of the above formula (1)) 3-Acryloxypropyltrimethoxysilane (Compound of the above formula (2)) Methyltriethoxysilane (Compound of the above formula (3)) Dimethyldimethoxysilane (Compound of the above formula (4)) Trifluoropropyltrimethoxysilane (Polymerization Catalyst) p-Toluenesulfonic acid monohydrate (water) Ion exchange water (Amide compounds) N,N-Dimethylacetamide (Orthoester) Trimethyl orthoacetate (Protective Reagent) Hexamethyldisilazane Trimethylsilane chloride

[0105] (Example 1) 73.2 g of methyltriethoxysilane, 12.4 g of dimethyldimethoxysilane, and 14.4 g of 3-acryloxypropyltrimethoxysilane were placed in a flask and stirred. On the other hand, a solution obtained by mixing 0.055 g of p-toluenesulfonic acid monohydrate and 23.2 g of ion exchange water was prepared. The solution was added dropwise to the flask over 15 minutes so that the temperature did not exceed 60° C. After the addition, stirring was performed at a temperature of 60° C. for 3 hours (“Step (1)”). After cooling, 24.9 g of N,N-dimethylacetamide was added and stirred. Then, 32.5 g of trimethyl orthoacetate was added dropwise so that the temperature did not exceed 30°C. Then, methanol, ethanol and water as by-products were removed by distillation under reduced pressure to obtain a concentrated solution of a siloxane compound containing a terminal silanol group ("step (2)"). To the concentrated solution of the siloxane compound containing a terminal silanol group, 40.8 g of ethyl acetate and 35.0 g of acetic anhydride were added and stirred. Then, 61.4 g of hexamethyldisilazane was added dropwise so that the temperature did not exceed 30° C., thereby obtaining a solution of a siloxane compound terminated with hexamethyldisilazane (“step (3)”). 40.8 g of hexane and 40.8 g of ion exchange water were added to the solution of the siloxane compound terminated by hexamethyldisilazane, stirred with a separatory funnel, and allowed to stand until separated into an organic layer and an aqueous layer, and the aqueous layer was removed after separation. After the aqueous layer was removed, a separation operation was performed using ion exchange water and a saturated sodium bicarbonate aqueous solution to take out the organic layer. 10.0 g of sodium sulfate was added to the taken out organic layer, and the mixture was stirred for 10 minutes to dehydrate the mixture. Then, the solution was filtered using a filter. Next, the solution was evaporated under reduced pressure at 60°C for 1 hour and then evaporated under reduced pressure at 120°C for 3 hours to evaporate low boiling point components other than the siloxane compound, thereby obtaining a solvent-free siloxane composition containing a siloxane compound. In addition, the mass ratio of the structural unit derived from formula (1) is represented by w 1 , the mass ratio of the structural unit derived from formula (2) is set to w 2 , the mass ratio of the structural unit derived from formula (3) is set to w 3 , the mass ratio of the structural unit derived from formula (4) is set to w 4 , as shown in Table 1.

[0106] (Examples 2 to 4, 6, Comparative Examples 1 to 2) Except having changed the addition amount of each material as described in Table 1, it carried out similarly to Example 1, and obtained the solvent-free siloxane composition. In addition, Table 1 shows the addition amount of various materials used in the above step (1) and the addition amount of hexamethyldisilazane used in the above step (3). In addition, Table 1 shows the above mass ratio w 1 , mass ratio w 2 , mass ratio w 3 , mass ratio w 4 .

[0107] (Example 5) A solvent-free siloxane composition was obtained in the same manner as in Example 1 except that the addition amounts of various materials were changed as shown in Table 1, the dropwise addition amount of hexamethyldisilazane in step (2) was 76.9 g, and the addition amount of acetic anhydride in step (3) was 43.8 g. In addition, the addition amount of each material used in the above step (1) and the addition amount of hexamethyldisilazane used in the above step (3) are recorded in Table 1. In addition, the above mass ratio w is shown in Table 1. 1 , mass ratio w 2 , mass ratio w 3 , mass ratio w 4 .

[0108] (Example 7) After carrying out steps (1) and (2) in the same manner as in Example 1, 33.0 g of ethyl acetate was added to the concentrated solution of the siloxane compound containing a terminal silanol group, and the mixture was stirred. Subsequently, 66.8 g of trimethylsilyl chloride was added dropwise so that the temperature did not exceed 30° C., thereby obtaining a solution of a siloxane compound capped with trimethylsilyl chloride (“step (3)”). A solvent-free silicone composition containing a silicone compound was obtained in the same manner as in Example 1 except for the above.

[0109] [Table 1]

[0110] <Stability over time> The viscosity and weight average molecular weight of the siloxane compositions of Examples and Comparative Examples were measured immediately after preparation and after storage at 40° C. for one week, and evaluated according to the following criteria. The viscosity was measured using a R115 type viscometer RE-105L (E type viscometer, manufactured by Toki Sangyo Co., Ltd.) (measurement temperature: 25° C.), and the method described in the present specification was used for the weight average molecular weight. (Evaluation Criteria) 0: The increase in viscosity and weight average molecular weight is less than 15%; △: The increase in viscosity and weight average molecular weight is more than 15%; ×: Gelated.

[0111] <Measurement of the refractive index and film thickness of the cured film> The siloxane compositions of Examples and Comparative Examples and 5% by mass of a polymerization initiator (Omnirad 184, manufactured by TIANJIN NEW MATERIALS) based on the siloxane compound were dissolved in tetrahydrofuran (THF), and the tetrahydrofuran was removed by reduced pressure distillation. Next, 1.5 g of the solvent-free siloxane composition was applied to a glass substrate by spin coating at 3000 rpm for 60 seconds, and then placed in a plastic bag, and the air inside was replaced with nitrogen so that the cumulative light intensity was 3000 mJ / cm 2 The 365nm UV light is irradiated to form a cured film. Finally, the refractive index and film thickness of the cured film at a wavelength of 550 nm were measured using a microspectroscopic film thickness meter OPTM series (manufactured by Otsuka Electronics Co., Ltd.).

[0112] [Table 2]

[0113] From Table 2, it was confirmed that the solvent-free silicone composition of the example was excellent in stability over time and the refractive index of the cured film was low. Industrial Applicability

[0114] The present invention can provide a solvent-free silicone composition which is excellent in stability over time and has a low refractive index of a cured film.

Claims

1. A solvent-free silicone composition comprising a silicone compound and satisfying the following conditions 1 and 2, The siloxane compound comprises a structural unit derived from the following formula (1) and a structural unit selected from the group consisting of at least one of the following formulas (2) to (4), and the terminal silanol group is capped with at least one selected from the group consisting of hexamethyldisilazane, trimethylsilyl chloride, trimethylsilyl acetate, N-(trimethylsilyl)diethylamine, N-trimethylsilylacetamide and N-(trimethylsilyl)dimethylamine, Si(A 1 )(A 2 ) a (OR 1 ) 3-a (1) In formula (1), A 1 represents a monovalent organic group having a free radical polymerizable double bond, A 2 represents an alkyl group or a silyl group, R 1 Represents an alkyl group; multiple R 1 can be the same or different; a is 0 or 1; Si(B 1 )(B 2 ) b (OR 2 ) 3-b (2) In formula (2), B 1 represents an alkyl group, B 2 Represents silyl group, R 2 Represents an alkyl group; multiple R 2 can be the same or different; b is 0 or 1; Si(C 1 )2(C 2 ) c (OR 3 ) 2-c (3) In formula (3), C 1 represents an alkyl group, C 2 Represents silyl group, R 3 Represents an alkyl group; two C 1 Can be the same or different, multiple R 3 Can be the same or different; c is 0 or 1; Si(D 1 )(D 2 ) d (OR 4 ) 3-d (4) In formula (4), D 1 represents a fluoroalkyl group having 3 to 13 fluorine atoms, D 2 represents an alkyl group, a silyl group or a monovalent organic group having a free radical polymerizable double bond, R 4 Represents an alkyl group; multiple R 4 Can be the same or different; d is 0 or 1; Condition 1 The refractive index of the cured coating is less than 1.45; Condition 2 For the siloxane compound, when the mass ratio of the structural units derived from the formula (1) relative to all the structural units is set to w1, the mass ratio of the structural units derived from the formula (2) is set to w2, the mass ratio of the structural units derived from the formula (3) is set to w3, and the mass ratio of the structural units derived from the formula (4) is set to w4, w1 is 10 to 30, w2 is 0 to 90, w3 is 0 to 90, w4 is 0 to 90, and w2+w3+w4 is 70 to 90.

2. The solvent-free silicone composition according to claim 1, wherein The siloxane compound has structural units derived from at least two selected from the group consisting of the formula (2), the formula (3), and the formula (4).

3. The solvent-free silicone composition according to claim 1 or 2, wherein: The siloxane compound has structural units derived from the formula (2) and the formula (3).

4. The solvent-free silicone composition according to claim 1 or 2, wherein: The mass ratio w1 of the structural unit derived from the formula (1) in the siloxane compound is 20 or less.

5. The solvent-free silicone composition according to claim 1 or 2, wherein: The weight average molecular weight of the siloxane compound is 800 to 10,000.

6. A method for producing a siloxane compound, comprising the following steps (1), (2) and (3) in sequence, Process (1) A step of reacting the following formula (1) with at least one selected from the group consisting of the following formulas (2) to (4) to prepare a siloxane compound having a silanol group at the end, Si(A 1 )(A 2 ) a (OR 1 ) 3-a (1) In formula (1), A 1 represents a monovalent organic group having a free radical polymerizable double bond, A 2 represents an alkyl group or a silyl group, R 1 Represents an alkyl group; multiple R 1 can be the same or different; a is 0 or 1; Si(B 1 )(B 2 ) b (OR 2 ) 3-b (2) In formula (2), B 1 represents an alkyl group, B 2 Represents silyl group, R 2 Represents an alkyl group; multiple R 2 can be the same or different; b is 0 or 1; Si(C 1 )2(C 2 ) c (OR 3 ) 2-c (3) In formula (3), C 1 represents an alkyl group, C 2 Represents silyl group, R 3 Represents an alkyl group; two C 1 Can be the same or different, multiple R 3 Can be the same or different; c is 0 or 1; Si(D 1 )(D 2 ) d (OR 4 ) 3-d (4) In formula (4), D 1 represents a fluoroalkyl group having 3 to 13 fluorine atoms, D 2 represents an alkyl group, a silyl group or a monovalent organic group having a free radical polymerizable double bond, R 4 Represents an alkyl group; multiple R 4 Can be the same or different; d is 0 or 1; Process (2) After adding the amide compound, dehydration with the orthoester and solvent evaporation are performed; Process (3) A step of obtaining a blocked siloxane compound by dissolving the siloxane compound having a silanol group at the end in an organic solvent and then adding at least one selected from the group consisting of hexamethyldisilazane, trimethylsilyl chloride, trimethylsilyl acetate, N-(trimethylsilyl)diethylamine, N-trimethylsilylacetamide and N-(trimethylsilyl)dimethylamine.

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