JPWO2015098738A1 - Polyalkoxysilazane, method for producing the same, coating composition and silicon-based ceramic coating obtained therefrom - Google Patents

Abstract

The polyalkoxysilazane of the present invention has at least one of a structural unit represented by the following general formula (i) and a structural unit represented by the following general formula (ii). [R1O-Si- (NH) 3/2] (i) (wherein R1 represents an alkyl group) [(R2O) 2-Si- (NH) 2/2] (ii) (wherein R2 Represents an alkyl group, and two R 2 s may be the same or different.

Description

  The present invention relates to polyalkoxysilazane and a method for producing the same, as well as a coating composition and a silicon-based ceramic coating obtained therefrom.

Polysilazane coating agents are classified as a type of ceramic coating agent, and it is known that a coating layer having excellent heat resistance, wear resistance, corrosion resistance, and the like can be formed. As a specific polysilazane coating agent, a coating composition containing perhydroxypolysilazane (PHPS) represented by [—SiH ₂ —NH—] _n is known. When fired, a silica film can be obtained (see, for example, Patent Document 1).
However, the PHPS-based coating agent requires high-temperature heating (for example, 400 ° C. or higher) for silica conversion of the coating film, which requires energy costs and requires special equipment for heat treatment. was there. Furthermore, there is a problem that it cannot be applied to a substrate having insufficient heat resistance.
Therefore, various compositions capable of reducing the silica conversion temperature have been studied, and Patent Documents 2 to 4 disclose PHPS-based coating agents containing a catalyst and the like.

JP 60-145903 A Japanese Patent Laid-Open No. 06-299118 JP-A-11-116815 JP 09-31333 A

  However, in the case of a coating agent that lowers the silica conversion temperature by adding a catalyst or the like, there is a problem that a high-purity silica film cannot be obtained as a result because it remains as an impurity in the coating film. . Furthermore, in some cases, such as a problem that the silica film is colored depending on the catalyst used.

  The present invention relates to a polyalkoxysilazane that can be converted into a silicon-based ceramic coating without adding a catalyst or the like and without performing a heat treatment at a high temperature, a method for producing the same, a coating composition, and a silicon-based ceramic coating. The purpose is to provide.

（式中、Ｒ¹はアルキル基を示す。）

（式中、Ｒ²はアルキル基を示す。２つのＲ²は、互いに同一でもよいし、異なってもよい。）
［２］上記一般式（ｉ）で表される構成単位、及び上記一般式（ｉｉ）で表される構成単位の両方を有する上記［１］に記載のポリアルコキシシラザン。
［３］上記一般式（ｉ）におけるＲ¹の炭素数は１〜１０であり、上記一般式（ｉｉ）におけるＲ²の炭素数は１〜１０である上記［１］又は［２］に記載のポリアルコキシシラザン。
［４］下記一般式（１）で表される上記［１］乃至［３］のいずれか一項に記載のポリアルコキシシラザン。

（式中、Ｒ¹、Ｒ²及びＲ³は、それぞれ、独立して、アルキル基を示す。Ｒ¹を複数含む場合、複数のＲ¹は、互いに同一でもよいし、異なってもよい。複数のＲ²は、互いに同一でもよいし、異なってもよい。複数のＲ³は、互いに同一でもよいし、異なってもよい。ａ、ｂ、ｃ及びｄは、それぞれ、独立して、０又は正の数である。但し、ｂ及びｃのうちの少なくとも一方は正の数であり、且つ、ｂが０である場合には、ａ及びｄのうち少なくとも一方は正の数である。）
［５］上記一般式（１）におけるＲ³の炭素数は１〜１０である上記［４］に記載のポリアルコキシシラザン。
［６］ハロゲン化シラン化合物をアンモノリシス重縮合させて得られたポリアルコキシシラザンであり、
上記ハロゲン化シラン化合物が、下記一般式（２）で表される化合物を含む上記［１］乃至［５］のいずれか一項に記載のポリアルコキシシラザン。

（式中、Ｒ⁴はアルキル基を示す。Ｘ¹はハロゲン原子を示す。ｎは１又は２である。Ｒ⁴を複数含む場合、複数のＲ⁴は、互いに同一でもよいし、異なってもよい。Ｘ¹を複数含む場合、複数のＸ¹は、互いに同一でもよいし、異なってもよい。）
［７］上記一般式（２）におけるＲ⁴の炭素数が１〜３である上記［６］に記載のポリアルコキシシラザン。
［８］上記［１］乃至［７］のうちのいずれか一項に記載のポリアルコキシシラザンを含有することを特徴とするコーティング組成物。
［９］上記［８］に記載のコーティング組成物から得られることを特徴とするケイ素系セラミック被膜。
［１０］上記［１］乃至［７］のうちのいずれか一項に記載のポリアルコキシシラザンの製造方法であって、
ハロゲン化シラン化合物をアンモノリシス重縮合させる工程を備え、該工程において、上記ハロゲン化シラン化合物に含まれるハロゲン原子１当量に対し、−５０℃以下でアンモニア２当量以上を用いることを特徴とするポリアルコキシシラザンの製造方法。
［１１］上記ハロゲン化シラン化合物が下記一般式（２）で表される化合物を含む上記［１０］に記載のポリアルコキシシラザンの製造方法。

（式中、Ｒ⁴はアルキル基を示す。Ｘ¹はハロゲン原子を示す。ｎは１又は２である。Ｒ⁴を複数含む場合、複数のＲ⁴は、互いに同一でもよいし、異なってもよい。Ｘ¹を複数含む場合、複数のＸ¹は、互いに同一でもよいし、異なってもよい。）
［１２］上記一般式（２）におけるＲ⁴の炭素数が１〜３である上記［１１］に記載のポリアルコキシシラザンの製造方法。The present invention is as follows.
[1] A polyalkoxysilazane having at least one of a structural unit represented by the following general formula (i) and a structural unit represented by the following general formula (ii).

(In the formula, R ¹ represents an alkyl group.)

(In the formula, R ² represents an alkyl group. Two R ^{2 s} may be the same as or different from each other.)
[2] The polyalkoxysilazane according to [1], including both the structural unit represented by the general formula (i) and the structural unit represented by the general formula (ii).
[3] The carbon number of R ¹ in the general formula (i) is 1 to 10, and the carbon number of R ² in the general formula (ii) is 1 to 10, described in [1] or [2] Polyalkoxysilazane.
[4] The polyalkoxysilazane according to any one of [1] to [3], which is represented by the following general formula (1).

(Wherein, R ^1, R ² and R ³ are each, independently, when including a plurality of .R ¹ represents an alkyl group, a plurality of R ¹ may be mutually the same or different. More R ^{2 s} may be the same as or different from each other, and a plurality of R ³ may be the same or different from each other, and a, b, c and d are each independently 0 or (It is a positive number, provided that at least one of b and c is a positive number, and when b is 0, at least one of a and d is a positive number.)
[5] The polyalkoxysilazane according to the above [4], wherein R ³ in the general formula (1) has 1 to 10 carbon atoms.
[6] A polyalkoxysilazane obtained by ammonolytic polycondensation of a halogenated silane compound,
The polyalkoxysilazane according to any one of [1] to [5], wherein the halogenated silane compound includes a compound represented by the following general formula (2).

(Wherein, when R ⁴ is .X ¹ represents an alkyl group .n showing a halogen atom including a plurality of .R ⁴ is 1 or 2, a plurality of R ⁴ may be mutually the same or different when containing a plurality of good .X ^1, a plurality of X ¹ may be mutually the same or different.)
[7] The polyalkoxysilazane according to the above [6], wherein R ⁴ in the general formula (2) has 1 to 3 carbon atoms.
[8] A coating composition comprising the polyalkoxysilazane according to any one of [1] to [7].
[9] A silicon-based ceramic coating obtained from the coating composition according to [8].
[10] The method for producing a polyalkoxysilazane according to any one of [1] to [7] above,
A polyalkoxy comprising a step of subjecting a halogenated silane compound to an ammonolytic polycondensation, wherein in this step, 2 equivalents or more of ammonia is used at -50 ° C. or less with respect to 1 equivalent of a halogen atom contained in the halogenated silane compound. A method for producing silazane.
[11] The method for producing a polyalkoxysilazane according to [10], wherein the halogenated silane compound includes a compound represented by the following general formula (2).

(Wherein, when R ⁴ is .X ¹ represents an alkyl group .n showing a halogen atom including a plurality of .R ⁴ is 1 or 2, a plurality of R ⁴ may be mutually the same or different when containing a plurality of good .X ^1, a plurality of X ¹ may be mutually the same or different.)
[12] The method for producing a polyalkoxysilazane according to the above [11], wherein R ⁴ in the general formula (2) has 1 to 3 carbon atoms.

The polyalkoxysilazane of the present invention is a novel compound having a specific configuration, and when this compound is used, the resulting film can be converted into a silicon-based ceramic film without heat treatment at high temperatures. is there. Furthermore, it is excellent in solubility in organic solvents such as propylene glycol methyl ether acetate, toluene, tetrahydrofuran, 1,2-dimethoxyethane, diethylene glycol dimethyl ether, and dibutyl ether, and is excellent in operability.
According to the coating composition containing the polyalkoxysilazane of the present invention, it is easy to form a film without adding a catalyst or the like, and a coating film is formed by the composition, the solvent is removed, and then at a high temperature. Without performing the heat treatment, for example, the silicon-based ceramic coating can be obtained by treatment under a low temperature condition of 20 ° C. or more and less than 100 ° C. Therefore, it is possible to suppress impurities from being mixed into the silicon-based ceramic coating and reduce defects such as coloring of the silicon-based ceramic coating.
Since the silicon-based ceramic coating of the present invention is a coating obtained from the above coating composition, it has high purity and can be formed regardless of the heat resistance of the object to be coated. Moreover, it is excellent in heat resistance, abrasion resistance, corrosion resistance, and the like.
According to the polyalkoxysilazane production method of the present invention, stable polyalkoxysilazane can be efficiently produced without causing gelation or the like.

3 is an IR chart of polyalkoxysilazane obtained in Synthesis Example 1. 4 is an IR chart of polyalkoxysilazane obtained in Synthesis Example 2. 6 is an IR chart of polyalkoxysilazane obtained in Synthesis Example 5. 6 is an IR chart of polyalkoxysilazane obtained in Synthesis Example 6. 6 is an IR chart of polyalkoxysilazane obtained in Synthesis Example 7. 10 is an IR chart of polyalkoxysilazane obtained in Synthesis Example 8. 6 is an IR chart of polyalkoxysilazane obtained in Synthesis Example 9. 6 is an IR chart of a dry film obtained from the polyalkoxysilazane solution of Example 4. 6 is an IR chart of the coating film obtained in Example 4. 6 is an IR chart of the coating obtained in Example 5. FIG.

（式中、Ｒ¹はアルキル基を示す。）

（式中、Ｒ²はアルキル基を示す。２つのＲ²は、互いに同一でもよいし、異なってもよい。）The present invention will be described in detail below.
1. Polyalkoxysilazane The polyalkoxysilazane of the present invention is a structural unit represented by the following general formula (i) (hereinafter also referred to as “structural unit (i)”), and a structure represented by the following general formula (ii). It has at least one of units (hereinafter also referred to as “structural unit (ii)”).

(In the formula, R ¹ represents an alkyl group.)

(In the formula, R ² represents an alkyl group. Two R ^{2 s} may be the same as or different from each other.)

The alkyl group of R ¹ in the structural unit (i) may be linear, branched or cyclic. Moreover, it is preferable that the carbon number is 1-10, More preferably, it is 1-6, More preferably, it is 1-3.
Specific examples of the alkyl group include, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, t-butyl group, n-pentyl group, n-hexyl group, n -Heptyl group, 2-ethylhexyl group, n-octyl group, n-nonyl group, n-decyl group, cyclohexyl group and the like.

The description of the alkyl group of R ¹ in the structural unit (i) can be applied as it is to the alkyl group of R ² in the structural unit (ii).

（式中、Ｒ³はアルキル基を示す。３つのＲ³は、互いに同一でもよいし、異なってもよい。）

（式中、Ｒ⁵は、水素原子、アルキル基又はアルコキシル基を示す。ｍは１〜３の整数である。尚、Ｒ⁵は、水素原子又はアルキル基を１つ以上有し、Ｒ⁵を複数含む場合、複数のＲ⁵は、互いに同一でもよいし、異なってもよい。）In addition to the structural units (i) and (ii), the polyalkoxysilazane of the present invention is a structural unit represented by the following general formula (iii) (hereinafter also referred to as “structural unit (iii)”). , A structural unit represented by the following general formula (iv) (hereinafter, also referred to as “structural unit (iv)”), a structural unit represented by the following general formula (v) (hereinafter, “structural unit (v)”) Or the like.

(In the formula, R ³ represents an alkyl group. The three R ^{3 s} may be the same as or different from each other.)

(In the formula, R ⁵ represents a hydrogen atom, an alkyl group or an alkoxyl group. M represents an integer of 1 to 3. R ⁵ has one or more hydrogen atoms or alkyl groups, and R ^{5 represents} When a plurality of R ⁵ are included, the plurality of R ⁵ may be the same as or different from each other.)

Regarding the alkyl group of R ³ in the structural unit (iv), the description of the alkyl group of R ¹ in the structural unit (i) can be applied as it is.

Regarding the alkyl group of R ⁵ in the structural unit (v), the description of the alkyl group of R ¹ in the structural unit (i) can be applied as it is.
Moreover, the alkyl part in the alkoxyl group of R ⁵ may be any of linear, branched and cyclic. Moreover, it is preferable that the carbon number is 1-10, More preferably, it is 1-6, More preferably, it is 1-3.
Specific examples of the alkoxyl group include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, sec-butoxy group, t-butoxy group, n-pentyloxy group, and n-hexyloxy. Group, n-heptyloxy group, 2-ethylhexyloxy group, n-octyloxy group, n-nonyloxy group, n-decyloxy group, cyclohexyloxy group and the like.

  Further, when the total amount of the structural units contained in the polyalkoxysilazane of the present invention is 100 mol%, the total amount of the structural units (i) and (ii) depends on the solubility in organic solvents and the storage stability of the solution. From this viewpoint, it is preferably 10 to 100 mol%, more preferably 30 to 100 mol%, still more preferably 50 to 100 mol%.

（式中、Ｒ¹、Ｒ²及びＲ³は、それぞれ、独立して、アルキル基を示す。Ｒ¹を複数含む場合、複数のＲ¹は、互いに同一でもよいし、異なってもよい。複数のＲ²は、互いに同一でもよいし、異なってもよい。複数のＲ³は、互いに同一でもよいし、異なってもよい。ａ、ｂ、ｃ及びｄは、それぞれ、独立して、０又は正の数である。但し、ｂ及びｃのうちの少なくとも一方は正の数であり、且つ、ｂが０である場合には、ａ及びｄのうち少なくとも一方は正の数である。）In particular, the polyalkoxysilazane of the present invention is preferably a compound represented by the following general formula (1).

(Wherein, R ^1, R ² and R ³ are each, independently, when including a plurality of .R ¹ represents an alkyl group, a plurality of R ¹ may be mutually the same or different. More R ^{2 s} may be the same as or different from each other, and a plurality of R ³ may be the same or different from each other, and a, b, c and d are each independently 0 or (It is a positive number, provided that at least one of b and c is a positive number, and when b is 0, at least one of a and d is a positive number.)

  The polyalkoxysilazane represented by the general formula (1) is a compound in which the structural units (i) to (iv) are bonded by a silazane bond (Si—N bond). In the above formula (1), a, b, c and d represent the molar amounts of the respective structural units. In addition, the number of structural units contained in the polyalkoxysilazane may be only one type or two or more types for each of the structural units (i) to (iv). Further, the condensed form of the structural units in the actual polyalkoxysilazane molecule does not necessarily follow the arrangement order of the formula (1).

（式中、Ｒ⁴はアルキル基を示す。Ｘ¹はハロゲン原子を示す。ｎは１又は２である。Ｒ⁴を複数含む場合、複数のＲ⁴は、互いに同一でもよいし、異なってもよい。Ｘ¹を複数含む場合、複数のＸ¹は、互いに同一でもよいし、異なってもよい。）
上記一般式（２）において、ハロゲン原子Ｘ¹は、Ｆ、Ｃｌ、Ｂｒ又はＩである。これらのうち、Ｃｌ及びＢｒが好ましく、Ｃｌが特に好ましい。The polyalkoxysilazane of the present invention can be obtained by ammonolytic polycondensation of a halogenated silane compound.
At this time, as the halogenated silane compound, at least a compound represented by the following general formula (2) (hereinafter also referred to as “compound (M1)”) is used.

(Wherein, when R ⁴ is .X ¹ represents an alkyl group .n showing a halogen atom including a plurality of .R ⁴ is 1 or 2, a plurality of R ⁴ may be mutually the same or different when containing a plurality of good .X ^1, a plurality of X ¹ may be mutually the same or different.)
In the general formula (2), the halogen atom X ¹ is F, Cl, Br, or I. Of these, Cl and Br are preferred, and Cl is particularly preferred.

In the general formula (2), the compound when n is 1 is a raw material monomer that gives the structural unit (i). The compound when n is 2 is a raw material monomer that gives the structural unit (ii).
The alkyl group R ⁴ in the general formula (2) may be linear, branched or cyclic. Moreover, it is preferable that the carbon number is 1-10, More preferably, it is 1-6, More preferably, it is 1-3. In particular, when the number of carbon atoms is 1 to 3, the balance between the reactivity during ammonolysis polycondensation and the solvent solubility of the resulting polyalkoxysilazane is favorable.
Specific examples of the alkyl group include, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, t-butyl group, n-pentyl group, n-hexyl group, n -Heptyl group, 2-ethylhexyl group, n-octyl group, n-nonyl group, n-decyl group, cyclohexyl group and the like.

In the above general formula (2), the halogenated silane compound when n is 1, that is, the compound giving the above-mentioned structural unit (i), for example, methoxytrichlorosilane, ethoxytrichlorosilane, n-propoxytrichlorosilane, Isopropoxytrichlorosilane, n-butoxytrichlorosilane, sec-butoxytrichlorosilane, t-butoxytrichlorosilane, n-pentyloxytrichlorosilane, n-hexyloxytrichlorosilane, n-heptyloxytrichlorosilane, 2-ethylhexyloxytrichlorosilane , N-octyloxytrichlorosilane, n-nonyloxytrichlorosilane, n-decyloxytrichlorosilane, cyclohexyloxytrichlorosilane, and the like.
Examples of the halogenated silane compound when n is 2, that is, the compound giving the structural unit (ii) are, for example, dimethoxydichlorosilane, diethoxydichlorosilane, di-n-propoxydichlorosilane, diisopropoxy. Dichlorosilane, di-n-butoxydichlorosilane, di-sec-butoxydichlorosilane, di-t-butoxydichlorosilane, di-n-pentyloxydichlorosilane, di-n-hexyloxydichlorosilane, di-n-heptyl Examples include oxydichlorosilane, di-2-ethylhexyloxydichlorosilane, di-n-octyloxydichlorosilane, di-n-nonyloxydichlorosilane, di-n-decyloxydichlorosilane, and dicyclohexyloxydichlorosilane.
In addition, the compound illustrated as said compound (M1) may be used individually by 1 type, and may be used in combination of 2 or more type.

（式中、Ｒ⁶はアルキル基を示す。Ｘ²はハロゲン原子を示す。ｎは０又は３である。Ｒ⁶を複数含む場合、複数のＲ⁶は、互いに同一でもよいし、異なってもよい。Ｘ²を複数含む場合、複数のＸ²は、互いに同一でもよいし、異なってもよい。）

（式中、Ｒ⁷は、水素原子、アルキル基又はアルコキシル基を示す。Ｘ³はハロゲン原子を示す。ｍは１〜３の整数である。尚、Ｒ⁷は、水素原子又はアルキル基を１つ以上有し、Ｒ⁷を複数含む場合、複数のＲ⁷は、互いに同一でもよいし、異なってもよい。Ｘ³を複数含む場合、複数のＸ³は、互いに同一でもよいし、異なってもよい。）As the halogenated silane compound, in addition to the compound (M1), a compound represented by the following general formula (3) (hereinafter also referred to as “compound (M2)”), or the following general formula, as necessary. A compound represented by the formula (4) (hereinafter also referred to as “compound (M3)”) may be used.

(Wherein, if R ⁶ is .X ² represents an alkyl group including a plurality of .R ⁶ .n is 0 or 3 a halogen atom, a plurality of R ⁶ may be mutually the same or different when containing a plurality of good .X ^2, a plurality of X ² may be mutually the same or different.)

(In the formula, R ⁷ represents a hydrogen atom, an alkyl group or an alkoxyl group. X ³ represents a halogen atom. M is an integer of 1 to ^3. R ⁷ represents a hydrogen atom or an alkyl group. One has above, when including a plurality of R ^7, a plurality of R ⁷ may be identical to one another, if different, including a plurality of good .X ^3, a plurality of X ³ may be the same with each other, different May be good.)

In the general formula (3), the compound when n is 0 is a raw material monomer that gives the structural unit (iii). The compound when n is 3 is a raw material monomer that gives the structural unit (iv).
The description of the alkyl group of R ⁴ in the general formula (2) can be applied as it is to the alkyl group of R ⁶ in the general formula (3).
The halogen atom X ² in the general formula (3) is F, Cl, Br or I. Of these, Cl and Br are preferred, and Cl is particularly preferred.

Examples of the halogenated silane compound when n is 0 in the general formula (3), that is, the compound giving the structural unit (iii) include, for example, silicon tetrachloride, silicon tetrabromide and silicon tetraiodide. Is mentioned.
Examples of the halogenated silane compound when n is 3; that is, the compound giving the structural unit (iv) described above include, for example, trimethoxychlorosilane, triethoxychlorosilane, tri-n-propoxychlorosilane, triisopropoxychlorosilane, Tri-n-butoxychlorosilane, tri-sec-butoxychlorosilane, tri-t-butoxychlorosilane, tri-n-pentyloxychlorosilane, tri-n-hexyloxychlorosilane, tri-n-heptyloxychlorosilane, tri-2-ethylhexyl Examples include oxychlorosilane, tri-n-octyloxychlorosilane, tri-n-nonyloxychlorosilane, tri-n-decyloxychlorosilane, and tricyclohexyloxychlorosilane.
In addition, the compound illustrated as said compound (M2) may be used individually by 1 type, and may be used in combination of 2 or more type.

  Next, the compound (M3) represented by the general formula (4) will be described. The compound (M3) is a raw material monomer that gives the structural unit (v).

When R ⁷ in the general formula (4) is an alkyl group, the description of the alkyl group of R ⁴ in the general formula (2) can be applied as it is.
In addition, when R ⁷ is an alkoxyl group, the alkyl moiety may be any of linear, branched and cyclic. Moreover, it is preferable that the carbon number is 1-10, More preferably, it is 1-6, More preferably, it is 1-3.
Specific examples of the alkoxyl group include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, sec-butoxy group, t-butoxy group, n-pentyloxy group, and n-hexyloxy. Group, n-heptyloxy group, 2-ethylhexyloxy group, n-octyloxy group, n-nonyloxy group, n-decyloxy group, cyclohexyloxy group and the like.
Furthermore, the halogen atom X ³ in the general formula (4) is F, Cl, Br or I. Of these, Cl and Br are preferred, and Cl is particularly preferred.

  In the general formula (4), examples of the halogenated silane compound when m is 1 include a trihalogenated silane compound and an alkyltrichlorosilane compound. Examples of the trihalogenated silane compound include trichlorosilane, tribromosilane, and triiodosilane. Examples of the alkyltrichlorosilane compound include methyltrichlorosilane, ethyltrichlorosilane, n-propyltrichlorosilane, isopropyltrichlorosilane, n-butyltrichlorosilane, sec-butyltrichlorosilane, t-butyltrichlorosilane, n-pentyltrichlorosilane, n -Hexyltrichlorosilane, n-heptyltrichlorosilane, 2-ethylhexyltrichlorosilane, n-octyltrichlorosilane, n-nonyltrichlorosilane, n-decyltrichlorosilane, cyclohexyltrichlorosilane and the like.

  Examples of the halogenated silane compound when m is 2 include dichlorosilane, alkyldichlorosilane compounds, alkoxydichlorosilane compounds, dialkyldichlorosilane compounds, and alkoxyalkyldichlorosilane compounds. Examples of the alkyldichlorosilane compound include methyldichlorosilane, ethyldichlorosilane, n-propyldichlorosilane, isopropyldichlorosilane, n-butyldichlorosilane, sec-butyldichlorosilane, t-butyldichlorosilane, n-pentyldichlorosilane, n -Hexyldichlorosilane, n-heptyldichlorosilane, 2-ethylhexyldichlorosilane, n-octyldichlorosilane, n-nonyldichlorosilane, n-decyldichlorosilane, cyclohexyldichlorosilane and the like. Examples of the alkoxydichlorosilane compound include methoxydichlorosilane, ethoxydichlorosilane, n-propoxydichlorosilane, isopropoxydichlorosilane, n-butoxydichlorosilane, sec-butoxydichlorosilane, t-butoxydichlorosilane, and n-pentyloxydichlorosilane. N-hexyloxydichlorosilane, n-heptyloxydichlorosilane, 2-ethylhexyloxydichlorosilane, n-octyloxydichlorosilane, n-nonyloxydichlorosilane, n-decyloxydichlorosilane and cyclohexyloxydichlorosilane It is done.

  Dialkyldichlorosilane compounds include dimethyldichlorosilane, diethyldichlorosilane, di-n-propyldichlorosilane, di-isopropyldichlorosilane, di-n-butyldichlorosilane, di-sec-butyldichlorosilane, and di-t-butyl. Dichlorosilane, di-n-pentyldichlorosilane, di-n-hexyldichlorosilane, di-n-heptyldichlorosilane, di-2-ethylhexyldichlorosilane, di-n-octyldichlorosilane, di-n-nonyldichlorosilane , Di-n-decyldichlorosilane, dicyclohexyldichlorosilane, and the like. Examples of the alkoxyalkyldichlorosilane compound include methoxymethyldichlorosilane, methoxyethyldichlorosilane, ethoxymethyldichlorosilane, ethoxyethyldichlorosilane, n-propoxymethyldichlorosilane, n-propoxyethyldichlorosilane, isopropoxymethyldichlorosilane, isopropoxy. Ethyldichlorosilane, n-butoxymethyldichlorosilane, n-butoxyethyldichlorosilane, sec-butoxymethyldichlorosilane, sec-butoxyethyldichlorosilane, t-butoxymethyldichlorosilane, t-butoxyethyldichlorosilane, n-pentyloxy Methyldichlorosilane, n-pentyloxyethyldichlorosilane, n-hexyloxymethyldichlorosilane, n-hexyloxyethyl Dichlorosilane, n-heptyloxymethyldichlorosilane, n-heptyloxyethyldichlorosilane, 2-ethylhexyloxymethyldichlorosilane, 2-ethylhexyloxyethyldichlorosilane, n-octyloxymethyldichlorosilane, n-octyloxyethyldichlorosilane N-nonyloxymethyldichlorosilane, n-nonyloxyethyldichlorosilane, n-decyloxymethyldichlorosilane, n-decyloxyethyldichlorosilane, cyclohexyloxymethyldichlorosilane, cyclohexyloxyethyldichlorosilane, and the like.

Furthermore, examples of the halogenated silane compound when m is 3 include monochlorosilane, dialkylchlorosilane compound, dialkoxychlorosilane compound, and trialkylchlorosilane compound. Dialkylchlorosilane compounds include dimethylchlorosilane, diethylchlorosilane, di-n-propylchlorosilane, di-isopropylchlorosilane, di-n-butylchlorosilane, di-sec-butylchlorosilane, di-t-butylchlorosilane, di-n-pentyl. Examples include chlorosilane, di-n-hexylchlorosilane, di-n-heptylchlorosilane, di-2-ethylhexylchlorosilane, di-n-octylchlorosilane, di-n-nonylchlorosilane, di-n-decylchlorosilane, and dicyclohexylchlorosilane. .
Examples of dialkoxychlorosilane compounds include dimethoxychlorosilane, diethoxychlorosilane, di-n-propoxychlorosilane, di-isopropoxychlorosilane, di-n-butoxychlorosilane, di-sec-butoxychlorosilane, di-t-butoxychlorosilane, di- n-pentyloxychlorosilane, di-n-hexyloxychlorosilane, di-n-heptyloxychlorosilane, di-2-ethylhexyloxychlorosilane, di-n-octyloxychlorosilane, di-n-nonyloxychlorosilane, di-n- Examples include decyloxychlorosilane and dicyclohexyloxychlorosilane.

Trialkylchlorosilane compounds include trimethylchlorosilane, triethylchlorosilane, tri-n-propylchlorosilane, tri-isopropylchlorosilane, tri-n-butylchlorosilane, tri-sec-butylchlorosilane, tri-t-butylchlorosilane, tri-n- Pentylchlorosilane, tri-n-hexylchlorosilane, tri-n-heptylchlorosilane, tri-2-ethylhexylchlorosilane, tri-n-octylchlorosilane, tri-n-nonylchlorosilane, tri-n-decylchlorosilane, tricyclohexylchlorosilane,
Dimethylethylchlorosilane, dimethyl-n-propylchlorosilane, dimethylisopropylchlorosilane, dimethyl-n-butylchlorosilane, dimethyl-sec-butylchlorosilane, dimethyl-t-butylchlorosilane, dimethyl-n-pentylchlorosilane, dimethyl-n-hexylchlorosilane, Dimethyl-n-heptylchlorosilane, dimethyl-2-ethylhexylchlorosilane, dimethyl-n-octylchlorosilane, dimethyl-n-nonylchlorosilane, dimethyl-n-decylchlorosilane, dimethylcyclohexylchlorosilane,
Methyldiethylchlorosilane, diethyl-n-propylchlorosilane, diethylisopropylchlorosilane, diethyl-n-butylchlorosilane, diethyl-sec-butylchlorosilane, diethyl-t-butylchlorosilane, diethyl-n-pentylchlorosilane, diethyl-n-hexylchlorosilane, Diethyl-n-heptylchlorosilane, diethyl-2-ethylhexylchlorosilane, diethyl-n-octylchlorosilane, diethyl-n-nonylchlorosilane, diethyl-n-decylchlorosilane, diethylcyclohexylchlorosilane,
Methyldi-t-butylchlorosilane, ethyldi-t-butylchlorosilane, isopropyldi-t-butylchlorosilane, di-t-butyll-n-pentylchlorosilane, di-t-butyl-n-hexylchlorosilane, di-t-butyl- n-heptylchlorosilane, di-t-butyl-2-ethylhexylchlorosilane, di-t-butyl-n-octylchlorosilane, di-t-butyl-n-nonylchlorosilane, di-t-butyl-n-decylchlorosilane and di- -T-butylcyclohexylchlorosilane and the like.
In addition, the compound illustrated as said compound (M3) may be used individually by 1 type, and may be used in combination of 2 or more type.
Preferred conditions for carrying out ammonolysis polycondensation will be described later.

2. Method for Producing Polyalkoxysilazane The method for producing polyalkoxysilazane in the present invention includes a polycondensation step (hereinafter also referred to as “first step”) using ammonolysis polycondensation using a halogenated silane compound as a raw material monomer. Is the method. Specifically, in the first step, 2 equivalents or more of ammonia are reacted at −50 ° C. or less with respect to 1 equivalent of halogen atoms contained in the halogenated silane compound. In the production method of the present invention, if necessary, after the first step, the reaction solvent, by-products, residual monomers, ammonia and the like are distilled off to recover polyalkoxysilazane (hereinafter referred to as “second step”). May also be provided.

  It is preferable that the raw material monomer used at the said 1st process contains the compound (M1) represented by the said General formula (2), Furthermore, this compound (M1) and the compound represented by the said General formula (3) (M2) or the compound (M3) represented by the general formula (4) can be used in combination. When using a plurality of raw material monomers, the proportion of the compound (M1) used is such that the reaction is smooth, and from the viewpoint of solvent solubility of the resulting polyalkoxysilazane and storage stability of the solution, the total amount of raw material monomers The amount is preferably 10 to 100 mol%, more preferably 30 to 100 mol%, still more preferably 50 to 100 mol%.

In the first step, a reaction solvent is usually used. Examples of the reaction solvent include diethyl ether, dibutyl ether, tetrahydrofuran, dioxane, ethers such as 1,2-dimethoxyethane (monoglyme) and diethylene glycol dimethyl ether (diglyme); aromatic hydrocarbon compounds such as benzene and toluene; n-hexane It is preferable to use aliphatic or alicyclic hydrocarbon compounds such as n-heptane and cyclohexane; dichloromethane, chloroform, dimethyl sulfoxide and pyridine. In addition, these reaction solvents may be used individually by 1 type, and may be used in combination of 2 or more type.
It is preferable that the usage-amount of a reaction solvent is 100-5000 mass parts with respect to 100 mass parts of raw material monomers, More preferably, it is 100-3000 mass parts, More preferably, it is 100-2000 mass parts.

  In the first step, the amount of ammonia used is preferably 1 equivalent or more, more preferably 1.5 equivalents or more, and even more preferably 2 equivalents or more with respect to 1 equivalent of halogen contained in the raw material monomer. When the amount of ammonia used is 1 equivalent or more, gelation during polycondensation is suppressed and polyalkoxysilazane is efficiently produced. The higher the amount of ammonia used, the higher the gelation suppression effect. However, when the amount used is too large, no significant difference is observed in the effect. From this viewpoint, the upper limit of the amount of ammonia used is usually 20 equivalents, preferably 15 equivalents, more preferably 10 equivalents.

In the first step, an auxiliary agent can be added to the reaction system for the purpose of promoting the reaction and facilitating the removal of by-product inorganic salts.
Examples of the auxiliary agent include triethylamine, diisopropylethylamine, 1-methylpiperidine, 1,4-diazabicyclo [2.2.2] octane (DABCO), tetramethylethylenediamine (TMEDA), pyridine, and 2,2′-bipyridine. And 1,10-phenanthroline.

  The reaction temperature in the first step is preferably −50 ° C. or lower. The lower limit is usually −100 ° C. If this temperature is −50 ° C. or lower, gelation during polycondensation tends to be suppressed, and polyalkoxysilazane is efficiently produced.

  The ammonolysis polycondensation reaction in the first step can be completed, for example, by confirming the disappearance of the raw material monomer by gas chromatography (GC).

  In the production method of the present invention, after the first step, a polyalkoxy is provided by providing a second step of distilling off the reaction solvent, by-products, residual monomers, ammonia and the like contained in the obtained reaction liquid. Silazane can be recovered. By not coexisting other components, the stability of the produced polyalkoxysilazane can be further improved.

3. Coating composition The coating composition of the present invention is characterized by containing the above-mentioned polyalkoxysilazane.
The coating composition of the present invention usually contains a solvent. Examples of the solvent include propylene glycol methyl ether acetate (PEGMEA), ethyl acetate, toluene, tetrahydrofuran (THF), 1,2-dimethoxyethane (monoglyme), diethylene glycol dimethyl ether (diglyme), dibutyl ether and xylene. In addition, these solvents may be used individually by 1 type, and may be used in combination of 2 or more type.

The concentration of the polyalkoxysilazane in the coating composition of the present invention is not particularly limited, but is preferably 1 to 50% by mass, more preferably 3 to 40% by mass when the total composition is 100% by mass. .
When this density | concentration is in the said range, the coating film which has a desired film thickness can be easily obtained with various coating methods.

In addition, other additives may be added to the coating composition of the present invention as long as the effects of the present invention are not impaired.
Examples of other additives include leveling agents, antifoaming agents, surfactants, plasticizers, antibacterial agents, antioxidants, dyes, pigments, preservatives, antifungal agents, rust preventives and deodorants. Is mentioned. In addition, these other additives may be used individually by 1 type, and may be used in combination of 2 or more type.

  Moreover, the preparation method of the coating composition of this invention is not specifically limited. Specifically, after mixing a polyalkoxysilazane and a solvent, it can be prepared by filtering as necessary.

4). Silicon-based ceramic coating The silicon-based ceramic coating of the present invention is obtained from the coating composition described above.
The silicon-based ceramic coating of the present invention is usually obtained by subjecting a coating formed on an object to be coated to an appropriate treatment.
Although the said to-be-coated article is not specifically limited, For example, it can be set as articles | goods containing a metal, ceramics, resin, wood, paper, glass, a stone material, etc. Specifically, a molded body containing inorganic particle powders such as metal nanoparticles and inorganic oxide particles, polycarbonate (PC), polyethylene terephthalate (PET) and the like can be mentioned.

The method for coating the coating composition with the coating composition is not particularly limited. Specifically, for example, various coating methods such as a spin coating method, a dipping method, a spray method, a bar coating method, and a roll coating method can be employed.
The thickness of the coating film can be appropriately controlled by adjusting the coating means, the solid content concentration and the viscosity in the composition, and the like.

  Moreover, the method of obtaining a silicon-type ceramic film from the coating film obtained with the coating composition is not specifically limited. For example, the solvent in the coating film is allowed to stand at room temperature, removed by heating, drying under reduced pressure, etc., and then the resulting film (dried film) is further cured or baked to obtain a silicon ceramic coating. Can do. Moreover, a silicon-based ceramic coating can be obtained by firing the coating film in which the solvent remains.

Specifically, a silicon-based ceramic coating is formed by curing a film (dry film) for a certain period of time under room temperature or a mild temperature condition of less than about 100 ° C. A silicon-based ceramic coating can also be obtained by firing a film (dry film). When firing, the firing temperature is generally about 100 to 2000 ° C.
When the film (dry film) is cured at a temperature of less than 100 ° C., the curing period is not particularly limited, but is about several hours to several weeks. On the other hand, when firing is performed, the firing time may be appropriately selected depending on the temperature, but is approximately 1 minute to 10 hours.

  A film made of silica can be obtained by curing or baking the film (dry film) in an atmosphere of air or water vapor. In the case of a nitrogen or ammonia atmosphere, a film made of a silicon oxynitride-like compound is obtained.

The film thickness of the silicon-based ceramic coating of the present invention is not particularly limited, but is preferably 1 nm to 1 mm, more preferably 1 nm to 500 μm, still more preferably 1 nm to 100 μm.
The film thickness can be measured with an electron microscope, ellipsometry, micrometer, or the like.

  Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to this embodiment.

1. Synthesis of polyalkoxysilazane Synthesis Example 1
Under a nitrogen atmosphere, methoxytrichlorosilane (22.34 g, 135 mmol) was weighed into a 500 mL four-necked flask equipped with a thermometer, a magnetic stirrer, a gas blowing tube and a Dimroth condenser, and dehydrated tetrahydrofuran (250 mL) was added. The methoxytrichlorosilane was dissolved and cooled in a dry ice-methanol bath. Next, using a gas blowing tube, ammonia was blown into a four-necked flask at 500 mL / min for 60 minutes while maintaining −50 ° C. or less (total amount: 30 L, 1.2 mol, chlorine of methoxytrichlorosilane) 3 times equivalent to atoms). After completion of blowing, the mixture was stirred at the same temperature for 1 hour. Subsequently, the dry ice-methanol bath was removed, and stirring was continued at 25 ° C. for 12 hours. Thereafter, the obtained reaction solution was filtered using a glass filter and washed with a small amount of dehydrated THF. Subsequently, the solvent in the obtained filtrate was distilled off under reduced pressure while maintaining the temperature at 40 ° C. or lower. And the residue was vacuum-dried and 6.44g of white powdery solid was obtained.
The obtained white powdery solid was analyzed by infrared spectroscopy (IR) to obtain an IR chart shown in FIG. Absorption derived from Si—NH—Si was observed in the vicinity of wave numbers 3320 (cm ⁻¹ ), 1180 (cm ⁻¹ ), and 910 (cm ⁻¹ ), and structural units derived from methoxytrichlorosilane [MeO—Si— ( It was confirmed that polymethoxysilazane composed of (NH) _3/2 ] was formed.
Further, it was confirmed that this polymethoxysilazane is soluble in propylene glycol methyl ether acetate, toluene, tetrahydrofuran, 1,2-dimethoxyethane and diethylene glycol dimethyl ether.

Synthesis example 2
Under a nitrogen atmosphere, weigh ethoxytrichlorosilane (12.12 g, 67.5 mmol) into a 500 mL four-necked flask equipped with a thermometer, a magnetic stirrer, a gas blowing tube and a Dimroth condenser, and add dehydrated tetrahydrofuran (125 mL). In addition, this ethoxytrichlorosilane was dissolved and cooled in a dry ice-methanol bath. Next, using a gas blowing tube, ammonia was blown into a four-necked flask at 500 mL / min for 30 minutes while maintaining −50 ° C. or lower (total amount: 15 L, 0.6 mol, ethoxytrichlorosilane) 3 times equivalent to chlorine atom). After completion of blowing, the mixture was stirred at the same temperature for 1 hour. Subsequently, the dry ice-methanol bath was removed, and stirring was continued at 25 ° C. for 12 hours. Thereafter, the obtained reaction solution was filtered using a glass filter and washed with a small amount of dehydrated THF. Subsequently, the solvent in the obtained filtrate was distilled off under reduced pressure while maintaining the temperature at 40 ° C. or lower. The residue was vacuum dried to obtain 6.10 g of a white powdery solid.
The obtained white powdery solid was analyzed by IR to obtain an IR chart shown in FIG. The production | generation of the polyethoxysilazane which consists of the structural unit [EtO-Si- (NH) _3/2 ] derived from ethoxytrichlorosilane was able to be confirmed.
Further, it was confirmed that this polyethoxysilazane is soluble in propylene glycol methyl ether acetate, toluene, tetrahydrofuran, 1,2-dimethoxyethane and diethylene glycol dimethyl ether.

Synthesis example 3
Under a nitrogen atmosphere, ethoxytrichlorosilane (19.38 g, 108 mmol) is weighed into a 500 mL four-necked flask equipped with a thermometer, a magnetic stirrer, a gas blowing tube and a Dimroth condenser, and dehydrated tetrahydrofuran (200 mL) is added. The ethoxytrichlorosilane was dissolved and cooled in a dry ice-methanol bath. Next, using a gas blowing tube, ammonia was blown into a four-necked flask at 400 mL / min for 30 minutes while maintaining −50 ° C. or less (total amount: 12 L, 0.48 mol, chlorine of ethoxytrichlorosilane) 1.5 equivalents to atoms). After completion of blowing, the mixture was stirred at the same temperature for 1 hour. Subsequently, the dry ice-methanol bath was removed, and stirring was continued at 25 ° C. for 12 hours. Thereafter, since the obtained reaction solution could not be filtered with a glass filter, the reaction solution was transferred to a centrifuge tube and centrifuged (10,000 rpm, 10 minutes) to precipitate ammonium chloride. Next, the supernatant was recovered and the solvent was distilled off under reduced pressure while maintaining the temperature at 40 ° C. or lower. And the residue was vacuum-dried and 7.87g of white powdery solid was obtained.
As a result of analyzing the obtained white powdery solid by IR, it was confirmed that polyethoxysilazane composed of structural units derived from ethoxytrichlorosilane was produced.
Further, it was confirmed that this polyethoxysilazane is soluble in propylene glycol methyl ether acetate, toluene, tetrahydrofuran, 1,2-dimethoxyethane and diethylene glycol dimethyl ether.

Synthesis example 4
Under a nitrogen atmosphere, ethoxytrichlorosilane (19.46 g, 108 mmol) was weighed into a 500 mL four-necked flask equipped with a thermometer, a magnetic stirrer, a gas blowing tube and a Dimroth condenser, and dehydrated tetrahydrofuran (200 mL) was added. The ethoxytrichlorosilane was dissolved and cooled in a dry ice-methanol bath. Next, using a gas blowing tube, ammonia was blown into a four-necked flask at 400 mL / min for 45 minutes while maintaining −50 ° C. or lower (total amount: 18 L, 0.72 mol, chlorine of ethoxytrichlorosilane) 2.2 times equivalent to atoms). After completion of blowing, the mixture was stirred at the same temperature for 1 hour. Subsequently, the dry ice-methanol bath was removed, and stirring was continued at 25 ° C. for 12 hours. Thereafter, the obtained reaction solution was filtered using a glass filter and washed with a small amount of dehydrated THF. Subsequently, the solvent in the obtained filtrate was distilled off under reduced pressure while maintaining the temperature at 40 ° C. or lower. And the residue was vacuum-dried and 9.07g of white powdery solid was obtained.
As a result of analyzing the obtained white powdery solid by IR, it was confirmed that polyethoxysilazane composed of structural units derived from ethoxytrichlorosilane was produced.
Further, it was confirmed that this polyethoxysilazane is soluble in propylene glycol methyl ether acetate, toluene, tetrahydrofuran, 1,2-dimethoxyethane and diethylene glycol dimethyl ether.

Synthesis example 5
The same operation as in Synthesis Example 2 was performed except that the use of ethoxytrichlorosilane (12.12 g, 67.5 mmol) was changed to the use of isopropoxytrichlorosilane (13.15 g, 67.9 mmol). 6.87 g of solid was obtained.
The obtained white powdery solid was analyzed by IR to obtain an IR chart shown in FIG. Production of polyisopropoxysilazane composed of a structural unit [iPrO-Si- (NH) _3/2 ] derived from isopropoxytrichlorosilane was confirmed.
Further, it was confirmed that this polyisopropoxysilazane is soluble in propylene glycol methyl ether acetate, toluene, tetrahydrofuran, 1,2-dimethoxyethane and diethylene glycol dimethyl ether.

Synthesis Example 6
Except for changing the use of ethoxytrichlorosilane (12.12 g, 67.5 mmol) to the use of ethoxytrichlorosilane (9.67 g, 53.9 mmol) and diethoxydichlorosilane (2.56 g, 13.5 mmol), The same operation as in Synthesis Example 2 was performed to obtain 6.69 g of a white powdery solid.
The obtained white powdery solid was analyzed by IR to obtain an IR chart shown in FIG. Structural unit derived from ethoxytrichlorosilane ([EtO-Si- (NH) _3/2 ]) and / or structural unit derived from diethoxydichlorosilane ([(EtO) ₂ -Si- (NH) _2/2 ] It was confirmed that polyethoxysilazane (modified product) consisting of
In addition, ²⁹ Si-NMR measurement using tetramethylsilane (TMS) as an internal standard substance confirmed a signal derived from a monoethoxy compound in the vicinity of −45 ppm and a signal derived from a diethoxy compound in the vicinity of −54 ppm. .
Furthermore, this polyethoxysilazane (modified product) was confirmed to be soluble in propylene glycol methyl ether acetate, toluene, tetrahydrofuran, 1,2-dimethoxyethane and diethylene glycol dimethyl ether.

Synthesis example 7
Except for changing the use of ethoxytrichlorosilane (12.12 g, 67.5 mmol) to the use of ethoxytrichlorosilane (10.96 g, 61.1 mmol) and diethoxydichlorosilane (1.45 g, 7.7 mmol), The same operation as in Synthesis Example 2 was performed to obtain 6.14 g of a white powdery solid.
The obtained white powdery solid was analyzed by IR to obtain an IR chart shown in FIG. The production | generation of the polyethoxysilazane (modified body) which consists of the structural unit derived from ethoxytrichlorosilane and / or the structural unit derived from diethoxydichlorosilane was able to be confirmed.
In addition, ²⁹ Si-NMR measurement using tetramethylsilane (TMS) as an internal standard substance confirmed a signal derived from a monoethoxy compound in the vicinity of −45 ppm and a signal derived from a diethoxy compound in the vicinity of −54 ppm. .
Furthermore, this polyethoxysilazane (modified product) was confirmed to be soluble in propylene glycol methyl ether acetate, toluene, tetrahydrofuran, 1,2-dimethoxyethane and diethylene glycol dimethyl ether.

Synthesis Example 8
Except for changing the use of ethoxytrichlorosilane (12.12 g, 67.5 mmol) to the use of ethoxytrichlorosilane (11.57 g, 64.5 mmol) and diethoxydichlorosilane (0.71 g, 3.8 mmol), The same operation as in Synthesis Example 2 was performed to obtain 6.58 g of a white powdery solid.
The obtained white powdery solid was analyzed by IR to obtain an IR chart shown in FIG. The production | generation of the polyethoxysilazane (modified body) which consists of the structural unit derived from ethoxytrichlorosilane and / or the structural unit derived from diethoxydichlorosilane was able to be confirmed.
In addition, ²⁹ Si-NMR measurement using tetramethylsilane (TMS) as an internal standard substance confirmed a signal derived from a monoethoxy compound in the vicinity of −45 ppm and a signal derived from a diethoxy compound in the vicinity of −54 ppm. .
Furthermore, this polyethoxysilazane (modified product) was confirmed to be soluble in propylene glycol methyl ether acetate, toluene, tetrahydrofuran, 1,2-dimethoxyethane and diethylene glycol dimethyl ether.

Synthesis Example 9
Under a nitrogen atmosphere, a 500 mL four-necked flask equipped with a thermometer, a magnetic stirrer, a gas blowing tube and a Dimroth condenser tube was charged with diethoxydichlorosilane (6.38 g, 33.7 mmol) and silicon tetrachloride (5.73 g, 33 0.7 mmol) was weighed and dehydrated tetrahydrofuran (125 mL) was added to dissolve the diethoxydichlorosilane and silicon tetrachloride, and the mixture was cooled in a dry ice-methanol bath. Next, using a gas blowing tube, ammonia was blown into a four-necked flask at 500 mL / min for 30 minutes while maintaining −50 ° C. or lower (total amount: 15 L, 0.60 mol, diethoxydichlorosilane and 3 times equivalent to chlorine atom of silicon tetrachloride). After completion of blowing, the mixture was stirred at the same temperature for 1 hour. Subsequently, the dry ice-methanol bath was removed, and stirring was continued at 25 ° C. for 12 hours. Thereafter, the obtained reaction solution was transferred to a centrifuge tube and centrifuged (10,000 rpm, 10 minutes) to precipitate ammonium chloride. Next, the supernatant was recovered and the solvent was distilled off under reduced pressure while maintaining the temperature at 40 ° C. or lower. And the residue was vacuum-dried and 3.60g of viscous liquid was obtained.
The resulting viscous liquid was analyzed by IR to obtain an IR chart shown in FIG. Polyethoxysilazane comprising a structural unit [(EtO) ₂ —Si— (NH) _2/2 ] derived from diethoxydichlorosilane and / or a structural unit [Si— (NH) _4/2 ] derived from silicon tetrachloride It was possible to confirm the production of (modified product).
Further, it was confirmed that this polyethoxysilazane (modified product) was soluble in propylene glycol methyl ether acetate, toluene, tetrahydrofuran, 1,2-dimethoxyethane and diethylene glycol dimethyl ether.

Comparative Synthesis Example 1
Under a nitrogen atmosphere, trichlorosilane (18.29 g, 135 mmol) was weighed into a 500 mL four-necked flask equipped with a thermometer, a magnetic stirrer, a gas blowing tube and a Dimroth condenser, and dehydrated tetrahydrofuran (250 mL) was added, This trichlorosilane was dissolved and cooled in a dry ice-methanol bath. Next, using a gas blowing tube, ammonia was blown into a four-necked flask at 500 mL / min for 60 minutes while maintaining −50 ° C. or less (total amount: 30 L, 1.2 mol, chlorine atom of trichlorosilane) 3 times equivalent). After completion of blowing, the mixture was stirred at the same temperature for 1 hour. Subsequently, the dry ice-methanol bath was removed, and stirring was continued at 25 ° C. for 12 hours. Thereafter, the obtained reaction solution was transferred to a centrifuge tube and centrifuged (10,000 rpm, 10 minutes) to precipitate ammonium chloride. Next, the supernatant was recovered and the solvent was distilled off under reduced pressure while maintaining the temperature at 40 ° C. or lower. And the residue was vacuum-dried and 1.16g of white powdery solid was obtained.
As a result of analyzing the obtained white powdery solid by infrared spectroscopy (IR), it was derived from Si—NH—Si in the vicinity of wave numbers 3360 (cm ⁻¹ ), 1160 (cm ⁻¹ ), and 920 (cm ⁻¹ ). Absorption was observed in the vicinity of 2130 (cm ^-1 ) and 810 (cm ^-1 ), Si-H-derived absorption, and polysilazane composed of a structural unit [H-Si- (NH) _3/2 ] derived from trichlorosilane. Was able to be confirmed.
This polysilazane was a compound hardly soluble in organic solvents such as propylene glycol methyl ether acetate, toluene, tetrahydrofuran, 1,2-dimethoxyethane, diethylene glycol dimethyl ether and the like.

2. Heat treatment of polyalkoxysilazane Example 1
About 150 mg of polymethoxysilazane obtained in Synthesis Example 1 was weighed on a platinum pan and placed in a quartz tube with a diameter of 20 mm. Then, it heated from the outside using the electric heater, flowing dry air or nitrogen at 100 ml / min in a quartz tube. At this time, the temperature was raised to a predetermined temperature at 20 ° C./min (400 ° C. under dry air and 800 ° C. under a nitrogen atmosphere) and maintained at that temperature for 2 hours. After cooling, the heat-treated sample remaining in the platinum pan was collected and analyzed by IR.
As a result, it was confirmed that when the temperature was raised to 400 ° C. under dry air and the heat treatment was performed for 2 hours, the silica was changed to silica (SiO ₂ ) having characteristic absorption at 3350 cm ⁻¹ and 1050 cm ⁻¹ .
Further, the temperature was raised to 800 ° C. under a nitrogen atmosphere, when 2 hours heat treatment is believed to 3200 cm ^-1, and of 1020 cm ^-1 and 920 cm ^-1 and a silicon oxynitride like having a characteristic absorption bimodal It was confirmed that the compound was changed to

Example 2
About 150 mg of polyethoxysilazane obtained in Synthesis Example 2 was weighed on a platinum pan and placed in a quartz tube having a diameter of 20 mm. Then, it heated from the outside using the electric heater, flowing dry air or nitrogen at 100 ml / min in a quartz tube. At this time, the temperature was raised to a predetermined temperature at 20 ° C./min (400 ° C. under dry air and 800 ° C. under a nitrogen atmosphere) and maintained at that temperature for 2 hours. After cooling, the heat-treated sample remaining in the platinum pan was collected and analyzed by IR.
As a result, it was confirmed that when the temperature was raised to 400 ° C. under dry air and the heat treatment was performed for 2 hours, the silica was changed to silica (SiO ₂ ) having characteristic absorption at 3350 cm ⁻¹ and 1050 cm ⁻¹ .
Further, the temperature was raised to 800 ° C. under a nitrogen atmosphere, when 2 hours heat treatment is believed to 3200 cm ^-1, and of 1020 cm ^-1 and 920 cm ^-1 and a silicon oxynitride like having a characteristic absorption bimodal It was confirmed that the compound was changed to

Example 3
About 150 mg of polyisopropoxysilazane obtained in Synthesis Example 5 was weighed on a platinum pan and placed in a quartz tube having a diameter of 20 mm. Then, it heated from the outside using the electric heater, flowing dry air or nitrogen at 100 ml / min in a quartz tube. At this time, the temperature was raised to a predetermined temperature at 20 ° C./min (400 ° C. under dry air and 800 ° C. under a nitrogen atmosphere) and maintained at that temperature for 2 hours. After cooling, the heat-treated sample remaining in the platinum pan was collected and analyzed by IR.
As a result, it was confirmed that when the temperature was raised to 400 ° C. under dry air and the heat treatment was performed for 2 hours, the silica was changed to silica (SiO ₂ ) having characteristic absorption at 3350 cm ⁻¹ and 1050 cm ⁻¹ .
Further, the temperature was raised to 800 ° C. under a nitrogen atmosphere, when 2 hours heat treatment is believed to 3200 cm ^-1, and of 1020 cm ^-1 and 920 cm ^-1 and a silicon oxynitride like having a characteristic absorption bimodal It was confirmed that the compound was changed to

3. Production and Evaluation of Coating Composition Example 4
2.0 g of polyethoxysilazane (modified product) obtained in Synthesis Example 6 was dissolved in 8.0 g of dehydrated dibutyl ether and filtered through a fluororesin membrane filter (0.2 μm). A 20 wt% solution was prepared.
Next, the obtained polyethoxysilazane solution was spin-coated at 2000 revolutions (15 seconds) on a silicon wafer cleaned with hydrofluoric acid. Thereafter, the solvent was removed by evaporation from the coating film at 60 ° C. (5 minutes) to obtain a dry film. The obtained dry film was analyzed by IR. This IR chart is shown in FIG.

Then, the dry film | membrane which uses the silicon wafer obtained above as a base material was baked at 400 degreeC in air | atmosphere for 3 hours, and the coating film was obtained.
The obtained film was analyzed by IR to obtain an IR chart shown in FIG. It was confirmed from the characteristic absorption of 1070 to 1080 cm ⁻¹ that it was converted to silica (SiO ₂ ). Moreover, as a result of measuring the obtained silica film (coating film) with an ellipsometer (laser wavelength; 633 nm), the film thickness was 300 nm and the refractive index was 1.432.

Example 5
Further, after a dry film was formed on the surface of the silicon wafer by the method described in Example 4, the silicon wafer with the film was allowed to stand at room temperature (23 ° C., humidity 50%) for 2 weeks in an air atmosphere. The film was obtained by curing.
The obtained coating was analyzed by IR to obtain an IR chart shown in FIG. It was confirmed from the characteristic absorption of 1070 to 1080 cm ⁻¹ that it was converted to silica (SiO ₂ ).

Comparative Example 1
Attempts were made to prepare the polysilazane solution obtained in Comparative Synthesis Example 1, but as described above, the solution was insoluble in various organic solvents, and a coating composition could not be obtained.

  From the results of the above examples, according to the coating composition containing the polyalkoxysilazane of the present invention, conversion into a silicon-based ceramic coating without adding a catalyst or the like and without performing a heat treatment at a high temperature. It was confirmed that it was possible.

  Since the polyalkoxysilazane and coating composition of the present invention do not require a catalyst, they are suitable for forming a high-purity silicon-based ceramic coating.

Claims (12)

A polyalkoxysilazane comprising at least one of a structural unit represented by the following general formula (i) and a structural unit represented by the following general formula (ii).

(In the formula, R ¹ represents an alkyl group.)

(In the formula, R ² represents an alkyl group. Two R ^{2 s} may be the same as or different from each other.)   2. The polyalkoxysilazane according to claim 1, having both the structural unit represented by the general formula (i) and the structural unit represented by the general formula (ii). ^3. The polyalkoxysilazane according to claim 1, wherein R ¹ in the general formula (i) has 1 to 10 carbon atoms, and R ² in the general formula (ii) has 1 to 10 carbon atoms. The polyalkoxysilazane according to any one of claims 1 to 3 represented by the following general formula (1).

(Wherein, R ^1, R ² and R ³ are each, independently, when including a plurality of .R ¹ represents an alkyl group, a plurality of R ¹ may be mutually the same or different. More R ^{2 s} may be the same as or different from each other, and a plurality of R ³ may be the same or different from each other, and a, b, c and d are each independently 0 or (It is a positive number, provided that at least one of b and c is a positive number, and when b is 0, at least one of a and d is a positive number.) The polyalkoxysilazane according to claim 4, wherein R ³ in the general formula (1) has 1 to 10 carbon atoms. Polyalkoxysilazane obtained by ammonolytic polycondensation of a halogenated silane compound,
The polyalkoxysilazane according to any one of claims 1 to 5, wherein the halogenated silane compound includes a compound represented by the following general formula (2).

(Wherein, when R ⁴ is .X ¹ represents an alkyl group .n showing a halogen atom including a plurality of .R ⁴ is 1 or 2, a plurality of R ⁴ may be mutually the same or different when containing a plurality of good .X ^1, a plurality of X ¹ may be mutually the same or different.) The polyalkoxysilazane according to claim 6, wherein R ⁴ in the general formula (2) has 1 to 3 carbon atoms.   A coating composition comprising the polyalkoxysilazane according to any one of claims 1 to 7.   A silicon-based ceramic coating obtained from the coating composition according to claim 8. A method for producing a polyalkoxysilazane according to any one of claims 1 to 7,
A polyalkoxy comprising a step of subjecting a halogenated silane compound to an ammonolytic polycondensation, wherein in this step, 2 equivalents or more of ammonia is used at -50 ° C. or less with respect to 1 equivalent of a halogen atom contained in the halogenated silane compound. A method for producing silazane. The method for producing polyalkoxysilazane according to claim 10, wherein the halogenated silane compound contains a compound represented by the following general formula (2).

(Wherein, when R ⁴ is .X ¹ represents an alkyl group .n showing a halogen atom including a plurality of .R ⁴ is 1 or 2, a plurality of R ⁴ may be mutually the same or different when containing a plurality of good .X ^1, a plurality of X ¹ may be mutually the same or different.) The method for producing a polyalkoxysilazane according to claim 11, wherein R ⁴ in General Formula (2) has 1 to 3 carbon atoms.

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