JPH09157594A - Polysilazane coating fluid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polysilazane coating liquid which is less harmful to the human body, has good handleability and can form a uniform silica coating film on a substrate by coating the substrate with the liquid and oxidizing the polysilazane by dissolving a specified polysilazane in, e.g. an aromatic solvent. SOLUTION: This coating liquid is prepared by dissolving a polysilazane having a skeleton mainly consisting of structural units represented by the formula and having a number-average molecular weight of about 100-50,000 and an Si/N atomic ratio of 0.7-3.0 on the average or a modified product thereof in at least either an aromatic compound such as benzene, xylene, ethylbenzene, diethylbenzene, trimethylbenzene or triethylbenzene or a compound such as cyclohexane, cyclohexene, decahydronaphthalene or dipentene.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polysilazane coating solution, and more specifically, it has less adverse effects on the human body and is easy to handle, and is capable of forming a uniform silica coating by coating this on a substrate and oxidizing it. A polysilazane coating solution capable of

[0002]

2. Description of the Related Art In recent years, polysilazane, which is a precursor polymer of silica, silicon nitride, and silicon oxynitride, has been attracting attention because a ceramic coating film having excellent heat resistance, abrasion resistance, corrosion resistance and the like can be obtained. When applying this polysilazane to a substrate, it is necessary to dissolve it in a suitable solvent, but since polysilazane is highly reactive compared to general organic polymers, it should be dissolved stably without reacting with polysilazane. There are few confirmed solvents, such as benzene, xylene, and toluene. Moreover,
As the solvent in this case, it is required to apply a polysilazane solution to a base material, which has little adverse effect on the human body and is easy to handle, and to form a homogeneous silica film when oxidized, No proposal has been made for such a solvent.

[0003]

SUMMARY OF THE INVENTION Therefore, the present invention has been made in view of the above-mentioned conventional state of the art, has less adverse effects on the human body and is easy to handle, and further, this polysilazane solution is used as a base material. It is an object of the present invention to provide a polysilazane coating solution capable of forming a uniform silica coating film by applying it on a substrate and oxidizing it.

[0004]

Means for Solving the Problems As a result of extensive studies, the present inventor has selected a suitable solvent according to the type of polysilazane to apply it to a substrate, and to give a homogeneous silica when oxidized. The inventors have found that a film can be formed and have reached the present invention.

That is, according to the present invention, firstly, the following general formula (I) is mainly used.

Embedded image A polysilazane or a modified product thereof having a skeleton composed of structural units represented by the formula (1) having a number average molecular weight of about 100 to 50,000 and an average atomic ratio of Si / N of 0.7 to 3.0. A polysilazane coating solution is provided which is dissolved in at least one compound selected from the following (i) and (ii). (I) aromatic compounds such as benzene, toluene, xylene, ethylbenzene, diethylbenzene, trimethylbenzene, triethylbenzene, (ii) cyclohexane,
Cyclohexene, decahydronaphthalene and dipentene. Secondly, mainly the following general formula (II)

Embedded image (In the formula, R ¹ , R ² and R ³ are each independently a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group or a group other than these groups which is directly bonded to silicon such as a fluoroalkyl group. Represents a group which is carbon, an alkylsilyl group, an alkylamino group or an alkoxy group, provided that one or two of R ¹ , R ² and R ³ are hydrogen atoms). The number average molecular weight having a skeleton is about 100 to 50,000, and Si /
It is characterized in that a polysilazane having a mean atomic ratio of N in the range of 0.7 to 3.0 or a modified product thereof is dissolved in at least one compound selected from the following (i) to (iii). A polysilazane coating solution is provided. (I) aromatic compounds such as benzene, toluene, xylene, ethylbenzene, diethylbenzene, trimethylbenzene and triethylbenzene, (ii) n-pentane, i
-Pentane, n-hexane, i-hexane, n-heptane, i-heptane, n-octane, i-octane, n-
Saturated hydrocarbon compounds such as nonane, i-nonane, n-decane, i-decane, (iii) ethylcyclohexane and dipentene.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The polysilazane used in the present invention has a number average molecular weight of about 100 to 50,000 having a skeleton mainly composed of the structural unit represented by the general formula (I) or (II), and an average atomic ratio of Si / N. Range is 0.7 to 3.0
Is polysilazane or a modified product thereof. of course,
The polysilazane can be used not only alone but also as a copolymer with another polysilazane or another polymer or a mixture of polysilazane and another compound. The polysilazane to be used has a chain structure, a cyclic structure, or a crosslinked structure,
Alternatively, there is a compound having these plural structures in the molecule at the same time, and these may be used alone or in a mixture.

The following are typical examples of polysilazanes to be used, but they are not limited to these. The one represented by the above general formula (I) is perhydropolysilazane, and its production method is described in, for example, JP-A-60-
145903, D.I. Seeferth et al Comm
unification of Am. Cer. Soc. ,
C-13, January 1983. Has been reported to. What is obtained by these methods is a mixture of polymers having various structures, but basically contains a chain portion and a cyclic portion in the molecule,

Embedded image Can be represented by the chemical formula:

An example of the structure of perhydropolysilazane is shown below.

Embedded image

A method for producing polysilazane having a hydrogen atom in R ¹ and R ² and a methyl group in R ³ in the general formula (II) is described in D. Seeyferth et al., Polym. Prepr.
Am. Chem. Soc. , Div. Polym. Ch
em ,. 25, 10 (1984). The polysilazane obtained by this method is a chain polymer having a repeating unit of — (SiH ₂ NCH ₃ ) — and a cyclic polymer, and neither has a crosslinked structure.

A method for producing a polyorgano (hydro) silazane having hydrogen atoms in R ¹ and R ² and an organic group in R ³ in the general formula (II) is described in D. Seeyferth et al., Polym.
Prepr. Am. Chem. Soc. , Div. Po
lym. Chem,. 25, 10 (1984) and JP-A-61-89230. The polysilazanes obtained by these methods include-(R ² SiHN
H)-is a repeating unit, and the degree of polymerization is mainly 3-5.
Having a cyclic structure of (R ³ SiHNH) _x [(R ² S
iH) _1.5 N] _1-X (0.4 <X <1) has a compound having a chain structure and a ring structure at the same time in the molecule.

In the above general formula (II), R ¹ is a hydrogen atom, R ² ,
Polysilazane having an organic group in R ³ , and those having an organic group in R ¹ and R ² and a hydrogen atom in R ³ are-(R ¹ R ² Si
NR ³ ) -is a repeating unit and the degree of polymerization is mainly 3-5.
It has a circular structure.

Next, of the polysilazanes to be used, typical examples other than those represented by the general formulas (I) and (II) will be given. The following polysilazanes can be treated in the same manner as those having the structural unit represented by the general formula (II). Some polyorgano (hydro) silazanes include D.I. Seeferth et al. Com
communication of Am. Cer. Soc.
C-132, July 1984. Some have a crosslinked structure in the molecule as reported. An example is as follows.

Embedded image

Further, polysilazane R ¹ Si (NH) _x or R having a crosslinked structure obtained by ammonia decomposition of R ¹ SiX ₃ (X: halogen) as reported in JP-A-49-69717. ¹ SiX ₃ and R ² ₂ Si
Polysilazane having the following structure obtained by co-ammonium decomposition of X ₂ can also be used as a starting material.

[Chemical 6]

The polysilazane to be used has a main skeleton composed of the unit represented by the general formula (I) or (II) as described above, and the unit represented by the general formula (I) or (II) is the above-mentioned unit. As is clear from the above, cyclization may occur, in which case the cyclic portion serves as a terminal group, and if such cyclization is not carried out, the ends of the main skeleton are R ¹ , R ² , R ³
It may be a group similar to or a hydrogen atom.

As the modified polysilazane, for example, a polymetallosilazane containing a metal atom as shown in the following structure (in the formula, the side chain metal atom M may be crosslinked) is also used as a starting material. be able to.

Embedded image

In addition, the repeating unit as reported in JP-A-62-195024 is [(SiH ₂ ) _n
(NH) _m ] and [(SiH ₂ ) _r O] (wherein
n, m, and r are 1, 2 and 3, respectively), and the heat resistance produced by reacting a boron compound with polysilazane as reported in JP-A-2-84437. Excellent polyborosilazanes, polymetallosilazanes produced by reacting polysilazanes with metal alkoxides as reported in JP-A-63-81212, JP-A-63-191832 and JP-A-2-77427. JP-A-1-138108, 1-
No. 138107, No. 1-203429, No. 1-203
No. 430, 4-63833 and 3-320167, the molecular weight was increased (the former four of the above publications) and the hydrolysis resistance was improved (the latter two). And inorganic silazane high polymers and modified polysilazanes described in JP-A-2-175726, JP-A-5-86200, and JP-A-5-86200.
Copolymerized silazanes, which are advantageous for thickening by introducing an organic component into polysilazane, as reported in JP-A Nos. 331293 and 3-31326, JP-A-5-238827, and JP-A-4-272020, No. 5-93275,
No. 5-214268, No. 5-30750, No. 5-3
No. 38524, a low temperature ceramic polysilazane which can be applied to a metal such as plastics or aluminum in which a polysilazane is added or added with a catalytic compound for accelerating the ceramic formation, and ceramicized at a lower temperature. Can be used in the same way.

In the present invention, the following low temperature ceramicized polysilazane can be used. For example, a silicon alkoxide-added polysilazane described in Japanese Patent Application No. 4-39595 by the applicant of the present application may be mentioned. This modified polysilazane is different from the polysilazane represented by the general formula (I) or (II) below in the general formula (III): Si (OR ⁴ ) ₄ (III) (wherein R ⁴ is the same or different. May represent a hydrogen atom, an alkyl group or an aryl group having 1 to 20 carbon atoms, and at least one R ⁴ is the above alkyl group or aryl group) and is reacted by heating. Alkoxide-derived silicon / obtained by
A silicon alkoxide-added polysilazane having a polysilazane-derived silicon atom ratio in the range of 0.001 to 3 and a number average molecular weight of about 200 to 500,000.

Another example of the low temperature ceramized polysilazane is glycidol-added polysilazane described in Japanese Patent Application Laid-Open No. 6-122852 by the present applicant. The modified polysilazane is obtained by reacting the polysilazane represented by the general formula (I) or (II) with glycidol and has a glycidol / polysilazane weight ratio of 0.001 to 2 and a number average molecular weight of about 200. ~
It is 500,000 glycidol-added polysilazanes.

Still another example of the low temperature ceramic polysilazane is an acetylacetonato complex-added polysilazane described in Japanese Patent Application No. 5-35604 filed by the present applicant. This modified polysilazane is a polysilazane represented by the general formula (I) or (II),
An acetylacetonato complex / polysilazane weight ratio obtained by reacting an acetylacetonato complex containing nickel, platinum, palladium or aluminum as a metal is within the range of 0.000001 to 2 and the number average molecular weight is about 2.
It is polysilazane with an acetylacetonato complex of 100,000 to 500,000. Acetylacetonato complexes including the metals, acetylacetone (2,4-pentanedione) Yin caused by acid dissociation of an ion acac ^- a complex is coordinated to a metal atom, in general formula (CH ₃ COCHCOCH _3)
n M [wherein M represents an n-valent metal].

Another example of the low temperature ceramized polysilazane is a metal carboxylate-added polysilazane described in Japanese Patent Application No. 5-93275 filed by the present applicant. The modified polysilazane is at least selected from the group consisting of the polysilazane represented by the general formula (I) or (II) and nickel, titanium, platinum, rhodium, cobalt, iron, ruthenium, osmium, palladium, iridium, or aluminum. A metal carboxylate having a metal carboxylate // polysilazane weight ratio in the range of 0.000001 to 2 and a number average molecular weight of about 200 to 500,000 obtained by reacting a metal carboxylate containing one metal. It is an addition polysilazane. The metal carboxylate is represented by the formula (RCOO) _n M [wherein, R is 1 to 2 carbon atoms.
Are two aliphatic groups or alicyclic groups, M represents at least one metal selected from the above metal group, and n is the valence of the metal M]. The metal carboxylate may be an anhydride or a hydrate. The metal carboxylate / polysilazane weight ratio is preferably 0.001 to 1, more preferably 0.01 to 1.
It is 0.5. For the preparation of the polysilazane to which the metal carboxylate is added, see the above-mentioned Japanese Patent Application No. 5-93275.

Further, in the present invention, the polysilazane having a main skeleton composed of the constitutional unit represented by the general formula (I) or (II) or a modified product thereof is added with amines or /
It is also possible to use, as a starting material, a composition to which and acids are added. This amine / acid-added polysilazane has an advantage that it can be converted into silica-based ceramics at low temperature and high speed. As the amines to be added, general formula R ⁶
R ⁷ R ⁸ N (wherein R ^{6 to} R ⁸ are an alkyl group, an alkenyl group,
It represents a cycloalkyl group, an aryl group, an alkylsilyl group, an alkylamino group, an alkoxy group or a hydrogen atom. )
In addition to the primary, secondary, and tertiary amines represented by, there are pyridines, DBU, DBN, and the like, and the added acids include organic acids such as acetic acid, propionic acid, and maleic acid, and hydrochloric acid, There are inorganic acids such as nitric acid and sulfuric acid. Incidentally, these amines and / or acids may be added after the raw material polysilazane is dissolved in an ester solvent described later.

The form of such polysilazane or polysilazane modified product is arbitrary. Therefore, the fiber,
Either bulk or powder may be used.

In the present invention, as a solvent for dissolving polysilazane, polysilazane having a skeleton mainly composed of the structural unit represented by the general formula (I) or a modified product thereof is described below in (i) and (ii). At least one compound selected from the above) is used. (I) aromatic compounds such as benzene, toluene, xylene, ethylbenzene, diethylbenzene, trimethylbenzene, triethylbenzene, (ii) cyclohexane,
Cyclohexene, decahydronaphthalene and dipentene. Further, for the polysilazane having a skeleton mainly composed of the structural unit represented by the general formula (II) or a modified product thereof, at least one compound selected from the following (i) to (iii) is used. (I) aromatic compounds such as benzene, toluene, xylene, ethylbenzene, diethylbenzene, trimethylbenzene and triethylbenzene, (ii) n-pentane, i
-Pentane, n-hexane, i-hexane, n-heptane, i-heptane, n-octane, i-octane, n-
Saturated hydrocarbon compounds such as nonane, i-nonane, n-decane, i-decane, (iii) ethylcyclohexane and dipentene.

As a method for dissolving polysilazane in the above solvent, any method can be adopted, but the following method is generally adopted. (1) The above solvent is added to polysilazane and simply stirred. (2) The polysilazane solution is gradually replaced with the above solvent having a high boiling point using a distillation device such as a rotary evaporator. Since polysilazane easily reacts with water, it is necessary to remove water from the solvent by adding molecular sieve or the like before use. The water content of the solvent is 1
It is preferable to set it to 00 ppm or less. The temperature at which the polysilazane is dissolved in the solvent is not particularly limited, but generally a temperature not lower than the freezing point and not higher than the boiling point of the solvent is adopted. The atmosphere in which the dissolution is performed is not particularly limited, but a dry air or dry nitrogen atmosphere is preferable because polysilazane easily reacts with moisture.

The solution obtained by dissolving polysilazane or its modified product in the above solvent can be used as it is as a coating solution. In the polysilazane coating solution of the present invention, a suitable filler and / or extender can be added, if necessary. The amount of filler added is 1 part by weight of polysilazane,
The amount added is in the range of 0.05 to 10 parts by weight, and the particularly preferred amount added is in the range of 0.2 to 3 parts by weight. The coating liquid may further contain various pigments, leveling agents, defoaming agents, antistatic agents, ultraviolet absorbers, pH adjusters, dispersants, surface modifiers, plasticizers, drying accelerators, anti-flow agents, if necessary. ,, etc. may be added. The concentration after the polysilazane is dissolved is not particularly limited, but is usually 0.01 to 80% by weight, preferably 0.1.
It is 1 to 50% by weight.

The base material to which the coating liquid of the present invention is applied is not particularly limited, and may be metal, glass, silicon plate, plastic,
Either wood or the like may be used. As a coating means, a usual coating method, for example, spin coating, dip coating, flow coating, roll coating or the like is used. Further, if the base material is sanded, degreased, surface-treated with various blasts or the like before coating, the adhesion performance of polysilazane (modified product) is improved.

A silica coating having a uniform surface can be easily obtained by applying the coating liquid of the present invention to a substrate, followed by drying and baking. In forming the silica film, a low temperature forming method (Japanese Patent Application No. 6-313425) by exposing to steam and / or immersing in distilled water containing a catalyst after heat treatment at 150 ° C. or lower, amines and / or Low-temperature formation method by dipping in an aqueous solution containing acids or contacting with steam generated from the aqueous solution, or by using a coating solution to which amines and / or acids are added and contacting with steam after coating (special Japanese Patent Application No. 7-200584) can also be used.

[0028]

The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the technical scope of the present invention.

Reference Example 1 [Synthesis of perhydropolysilazane] A four-necked flask having an internal volume of 1 liter was equipped with a gas blowing tube,
A mechanical stirrer and dewar condenser were installed. After replacing the inside of the reactor with deoxygenated dry nitrogen, 490 ml of degassed dry pyridine was put into a four-necked flask, and the mixture was cooled with ice. Next, 51.9 g of dichlorosilane
, A white solid adduct (SiH ₂ Cl ₂ · 2
C ₅ H ₅ N) was produced. The reaction mixture was cooled with ice, and while stirring, 51.0 g of purified ammonia was blown through a sodium hydroxide tube and an activated carbon tube, and then dry nitrogen was blown into the liquid layer to remove unreacted ammonia.

After the reaction was completed, the reaction mixture was centrifuged, washed with dry pyridine, and then filtered under a dry nitrogen atmosphere to obtain 850 ml of a filtrate. The solvent was removed from 5 ml of the filtrate under reduced pressure to obtain 0.102 g of a resinous solid perhydropolysilazane. When the number average molecular weight was measured by the benzene freezing point depression method, it was 600 g / mol.

Reference Example 2 [Synthesis of perhydropolysilazane containing methyl group] 10.0 g of perhydropolysilazane synthesized in Reference Example 1
Hexamethyldisilazane 2.00 g pyridine 190
It was dissolved in g and introduced into an autoclave made of SUS having a capacity of 500 ml, and the atmosphere was sufficiently replaced with dry nitrogen. This was heated to 80 ° C. in an oil bath while stirring and kept for 3 hours. When the solvent was removed under reduced pressure, resinous solid hexamethyldisilazane was added to the perhydropolysilazane 1
1.0 g was obtained. It was 650 g / mol when the number average molecular weight was measured by the benzene freezing point depression method.

Reference Example 3 [Synthesis of polymethyl (hydro) silazane] A four-necked flask having an inner volume of 500 ml was charged with a gas injection tube,
A mechanical stirrer and dewar condenser were installed. After the inside of the reactor was replaced with deoxygenated dry nitrogen, methyldichlorosilane (CH ₃ SiHC) was placed in a four-necked flask.
l ₂ , 24.3 g, 0.221 mol) and 300 ml of dry dichloromethane. The reaction mixture is ice-cooled, and 20.5 g (1.20 mol) of dry ammonia is stirred while stirring.
Was blown together with nitrogen gas to perform ammonia decomposition.

After the reaction was completed, the reaction mixture was centrifuged and then filtered. The solvent was removed from the filtrate under reduced pressure to obtain 8.79 g of polymethyl (hydro) silazane as a colorless liquid. When the number average molecular weight of the product was measured by the benzene freezing point depression method, it was 900 g / mol.

Comparative Example 1 The perhydropolysilazane synthesized in Reference Example 1 was dissolved in methylcyclohexane and adjusted to a concentration of 20% by weight.
After storing this at room temperature for 1 month, the number average molecular weight was measured and found to be 600 g / mol. This was spin-coated on a silicon plate under the condition of 3000 rpm × 20 seconds. This was baked at 450 ° C. for 1 hour in the air atmosphere. When the surface of the obtained coating film was observed under a microscope (120 times), many radial stripes were observed and it was non-uniform.

Comparative Example 2 The perhydropolysilazane synthesized in Reference Example 3 was dissolved in decahydronaphthalene and adjusted to a concentration of 20% by weight.
After storing this at room temperature for 1 month, the number average molecular weight was measured and found to be 900 g / mol. This was spin-coated on a silicon plate under the condition of 3000 rpm × 20 seconds. This was baked at 450 ° C. for 1 hour in the air atmosphere. When the surface of the obtained coating film was observed under a microscope (120 times), many radial stripes were observed and it was non-uniform.

Example 1 The perhydropolysilazane synthesized in Reference Example 1 was dissolved in benzene and the concentration was adjusted to 20% by weight. After storing it at room temperature for 1 month, the number average molecular weight was measured to be 6
It was 00 g / mol. 3000 on a silicon plate
Spin coating was performed under the conditions of rpm × 20 seconds. This was baked at 450 ° C. for 1 hour in the air atmosphere. Microscopic observation (120 times) of the surface of the obtained coating film revealed that it was homogeneous.

Example 2 The perhydropolysilazane synthesized in Reference Example 1 was dissolved in diethylbenzene and adjusted to a concentration of 20% by weight. After storing this at room temperature for 1 month, the number average molecular weight was measured and found to be 600 g / mol. This was spin-coated on a silicon plate under the condition of 3000 rpm × 20 seconds. This was baked at 450 ° C. for 1 hour in the air atmosphere. Microscopic observation (120 times) of the surface of the obtained coating film revealed that it was homogeneous.

Example 3 The perhydropolysilazane synthesized in Reference Example 1 was dissolved in decahydronaphthalene and adjusted to a concentration of 20% by weight.
After storing this at room temperature for 1 month, the number average molecular weight was measured and found to be 600 g / mol. This was spin-coated on a silicon plate under the condition of 3000 rpm × 20 seconds. This was baked at 450 ° C. for 1 hour in the air atmosphere. Microscopic observation (120 times) of the surface of the obtained coating film revealed that it was homogeneous.

Example 4 The perhydropolysilazane synthesized in Reference Example 1 was dissolved in dipentene and adjusted to a concentration of 20% by weight. After storing this at room temperature for 1 month, the number average molecular weight was measured.
It was 800 g / mol. 300 this on a silicon plate
Spin coating was performed under the conditions of 0 rpm × 20 seconds. This was baked at 450 ° C. for 1 hour in the air atmosphere. Microscopic observation (120 times) of the surface of the obtained coating film revealed that it was homogeneous.

Example 5 The perhydropolysilazane synthesized in Reference Example 1 was dissolved in decahydronaphthalene and adjusted to a concentration of 20% by weight.
100 g of this solution was placed in a glass four-necked flask and purged with dry nitrogen. Next, palladium propionate 0.
2 g was dissolved in 40 g decahydronaphthalene. This was gradually added to the perhydropolysilazane decahydronaphthalene solution with stirring at room temperature over 10 minutes.
After the obtained solution was stored at room temperature for 1 month, the number average molecular weight was measured and found to be 700 g / mol. This was spin-coated on a silicon plate under the condition of 3000 rpm × 20 seconds. This was baked at 450 ° C. for 1 hour in the air atmosphere. Microscopic observation (120 times) of the surface of the obtained coating film revealed that it was homogeneous.

Example 6 The methyl-containing perhydropolysilazane synthesized in Reference Example 2 was dissolved in m-xylene and adjusted to a concentration of 20% by weight. After storing this at room temperature for 1 month, the number average molecular weight was measured and found to be 650 g / mol. This was spin-coated on a silicon plate under the condition of 3000 rpm × 20 seconds. This was baked at 450 ° C. for 1 hour in the air atmosphere.
Microscopic observation (120 times) of the surface of the obtained coating film revealed that it was homogeneous.

Example 7 The methyl group-containing perhydropolysilazane synthesized in Reference Example 2 was dissolved in toluene and adjusted to a concentration of 20% by weight.
After storing this at room temperature for 1 month, the number average molecular weight was measured and found to be 650 g / mol. This was spin-coated on a silicon plate under the condition of 3000 rpm × 20 seconds. This was baked at 450 ° C. for 1 hour in the air atmosphere. Microscopic observation (120 times) of the surface of the obtained coating film revealed that it was homogeneous.

Example 8 The methyl group-containing perhydropolysilazane synthesized in Reference Example 2 was dissolved in n-hexane and adjusted to a concentration of 20% by weight. After storing this at room temperature for 1 month, the number average molecular weight was measured and found to be 650 g / mol. This was spin-coated on a silicon plate under the condition of 3000 rpm × 20 seconds. This was baked at 450 ° C. for 1 hour in the air atmosphere.
Microscopic observation (120 times) of the surface of the obtained coating film revealed that it was homogeneous.

Example 9 The methyl group-containing perhydropolysilazane synthesized in Reference Example 2 was dissolved in i-octane and adjusted to a concentration of 20% by weight. After storing this at room temperature for 1 month, the number average molecular weight was measured and found to be 650 g / mol. This was spin-coated on a silicon plate under the condition of 3000 rpm × 20 seconds. This was baked at 450 ° C. for 1 hour in the air atmosphere.
Microscopic observation (120 times) of the surface of the obtained coating film revealed that it was homogeneous.

Example 10 The methyl group-containing perhydropolysilazane synthesized in Reference Example 2 was dissolved in n-nonane and adjusted to a concentration of 20% by weight. 100 g of this solution was placed in a glass four-necked flask and purged with dry nitrogen. Next, 0.2 g of palladium propionate was dissolved in 40 g of n-nonane. This was gradually added to the perhydropolysilazane n-nonane solution with stirring at room temperature over 10 minutes. After the obtained solution was stored at room temperature for 1 month, the number average molecular weight was measured and found to be 720 g / mol. This on a silicon plate 3
Spin coating was performed under the condition of 000 rpm × 20 seconds. This was baked at 450 ° C. for 1 hour in the air atmosphere. Microscopic observation (120 times) of the surface of the obtained coating film revealed that it was homogeneous.

Example 11 The methyl group-containing perhydropolysilazane synthesized in Reference Example 3 was dissolved in m-xylene and adjusted to a concentration of 20% by weight. After storing this at room temperature for 1 month, the number average molecular weight was measured and found to be 900 g / mol. This was spin-coated on a silicon plate under the condition of 3000 rpm × 20 seconds. This was baked at 450 ° C. for 1 hour in the air atmosphere.
Microscopic observation (120 times) of the surface of the obtained coating film revealed that it was homogeneous.

Example 12 The methyl group-containing perhydropolysilazane synthesized in Reference Example 3 was dissolved in 1,3,5-trimethylbenzene and adjusted to a concentration of 20% by weight. After storing this at room temperature for 1 month, the number average molecular weight was measured to be 900 g / mol.
Met. This was spin-coated on a silicon plate under the condition of 3000 rpm × 20 seconds. This is the atmosphere, 450
Calcination was carried out at ℃ for 1 hour. Microscopic observation (120 times) of the surface of the obtained coating film revealed that it was homogeneous.

Example 13 The methyl group-containing perhydropolysilazane synthesized in Reference Example 3 was dissolved in n-pentane and adjusted to a concentration of 20% by weight. After storing this at room temperature for 1 month, the number average molecular weight was measured and found to be 900 g / mol. This was spin-coated on a silicon plate under the condition of 3000 rpm × 20 seconds. This was baked at 450 ° C. for 1 hour in the air atmosphere.
Microscopic observation (120 times) of the surface of the obtained coating film revealed that it was homogeneous.

Example 14 The methyl-containing perhydropolysilazane synthesized in Reference Example 3 was dissolved in n-decane and adjusted to a concentration of 20% by weight. After storing this at room temperature for 1 month, the number average molecular weight was measured and found to be 900 g / mol. This was spin-coated on a silicon plate under the condition of 3000 rpm × 20 seconds. This was baked at 450 ° C. for 1 hour in the air atmosphere.
Microscopic observation (120 times) of the surface of the obtained coating film revealed that it was homogeneous.

Example 15 The methyl group-containing perhydropolysilazane synthesized in Reference Example 3 was dissolved in n-nonane and adjusted to a concentration of 20% by weight. 100 g of this solution was placed in a glass four-necked flask and purged with dry nitrogen. Next, 0.2 g of palladium propionate was dissolved in 40 g of n-nonane. This was gradually added to the perhydropolysilazane n-nonane solution with stirring at room temperature over 10 minutes. After the obtained solution was stored at room temperature for 1 month, the number average molecular weight was measured and found to be 980 g / mol. This on a silicon plate 3
Spin coating was performed under the condition of 000 rpm × 20 seconds. This was baked at 450 ° C. for 1 hour in the air atmosphere. Microscopic observation (120 times) of the surface of the obtained coating film revealed that it was homogeneous.

[0051]

The polysilazane coating solution according to claim 1 has a number average molecular weight of about 100 to 50,000 having a skeleton mainly composed of the structural unit represented by the general formula (I), and Si / N Range of average atomic ratio is 0.7 to 3.0
The polysilazane or a modified product thereof is at least one compound selected from the following (i) and (ii), (i) an aromatic compound such as benzene, toluene, xylene, ethylbenzene, diethylbenzene, trimethylbenzene and triethylbenzene, (Ii) Since it is dissolved in cyclohexane, cyclohexene, decahydronaphthalene and dipentene, it has little adverse effect on the human body and is easy to handle, and furthermore, this polysilazane solution is applied to a substrate and oxidized. By doing so, it is possible to form a uniform silica coating.

The polysilazane coating solution of claim 2 has a number average molecular weight of about 100 to 50,000 having a skeleton mainly composed of the structural unit represented by the general formula (II),
In addition, a polysilazane or a modified product thereof having a Si / N average atomic ratio range of 0.7 to 3.0 can be prepared by
at least one compound selected from i), (i) aromatic compounds such as benzene, toluene, xylene, ethylbenzene, diethylbenzene, trimethylbenzene and triethylbenzene, (ii) n-pentane, i-pentane,
n-hexane, i-hexane, n-heptane, i-heptane, n-octane, i-octane, n-nonane, i-
Since it is dissolved in a saturated hydrocarbon compound such as nonane, n-decane, i-decane, etc., (iii) ethylcyclohexane and dipentene, it has little adverse effect on the human body and is easy to handle. By coating this substrate with this polysilazane solution and oxidizing it, it becomes possible to form a homogeneous silica coating.

Claims (2)

[Claims] 1. A compound represented by the following general formula (I): A polysilazane or a modified product thereof having a skeleton composed of structural units represented by the formula (1) having a number average molecular weight of about 100 to 50,000 and an average atomic ratio of Si / N of 0.7 to 3.0. And a polysilazane coating solution obtained by dissolving it in at least one compound selected from the following (i) and (ii). (I) aromatic compounds such as benzene, toluene, xylene, ethylbenzene, diethylbenzene, trimethylbenzene, triethylbenzene, (ii) cyclohexane,
Cyclohexene, decahydronaphthalene and dipentene. 2. A compound represented by the following general formula (II): (In the formula, R ¹ , R ² and R ³ are each independently a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group or a group other than these groups which is directly bonded to silicon such as a fluoroalkyl group. Represents a group which is carbon, an alkylsilyl group, an alkylamino group or an alkoxy group, provided that one or two of R ¹ , R ² and R ³ are hydrogen atoms). The number average molecular weight having a skeleton is about 100 to 50,000, and Si /
It is characterized in that a polysilazane having a mean atomic ratio of N in the range of 0.7 to 3.0 or a modified product thereof is dissolved in at least one compound selected from the following (i) to (iii). Polysilazane coating solution. (I) aromatic compounds such as benzene, toluene, xylene, ethylbenzene, diethylbenzene, trimethylbenzene and triethylbenzene, (ii) n-pentane, i
-Pentane, n-hexane, i-hexane, n-heptane, i-heptane, n-octane, i-octane, n-
Saturated hydrocarbon compounds such as nonane, i-nonane, n-decane, i-decane, (iii) ethylcyclohexane and dipentene.