JP2011052170A - Curable coating composition and cured coating film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curable coating composition from which an excellent coating film can be formed and which is excellent in storage stability when stored in a liquid state. <P>SOLUTION: The curable coating composition includes: polysiloxane having a carbon-carbon unsaturated group, which can be subjected to a hydrosilylation reaction, and a hydrosilyl group; and a solvent. The solvent includes no hydroxy group and has 80-130°C boiling point. The curable coating composition is excellent in storage stability and allows the cured coating film made therefrom to be uniform, flat and excellent in heat resistance. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a coating composition comprising a polysiloxane having a carbon-carbon unsaturated group and a hydrosilyl group capable of hydrosilylation reaction and a solvent, which can be crosslinked and cured, and a cured film formed. . The coating composition according to the present invention is excellent in storage stability in a liquid state, and can form a uniform and smooth film upon coating and curing.

  In the field of semiconductor devices and liquid crystal devices, in order to meet the demands for higher integration, higher speed, and multi-functionality, the pattern formed on the substrate is rapidly becoming finer and multi-layered. Therefore, a technique for flattening the unevenness of the element plane generated along with this is indispensable. A coating liquid called SOG (spin-on-glass) that gives a silica-based film after curing is often used as a planarizing film or an interlayer insulating film used in manufacturing a substrate of a semiconductor element or a liquid crystal element. In this method, a coating liquid containing an alkoxysilane hydrolyzate is applied on a substrate by a spin coating method or the like, and then volatile components are burned off by heat treatment, leaving a Si-O-Si bond. This is a method for forming a silica-based film.

  In such a flattening film and an interlayer insulating film, since a heating process is often repeated in the subsequent stage, a resin having higher heat resistance is required. For example, a carbon-carbon unsaturated group capable of hydrosilylation reaction and A polysiloxane having a hydrosilyl group has been proposed (see Patent Document 1). In Patent Document 1, there is a description that various organic solvents can be used as a solvent applicable to the polysiloxane, but a preferable combination is not described, and only THF (tetrahydrofuran) is disclosed as an example. Moreover, there was no description about the storage stability of the solution by various organic solvents.

  On the other hand, Patent Document 2 describes a silica-based curable coating composition containing a siloxane polymer and a solvent used in the SOG method, and examples of the solvent that can be used include butanol, ethyl lactate, propylene glycol monopropyl ether, and the like. Many protic solvents are exemplified, and it is disclosed that the solvent contains 55% or more of a solvent having a boiling point of 110 to 170 ° C. However, the siloxane polymer of Patent Document 2 does not contain a carbon-carbon unsaturated group capable of hydrosilylation reaction.

  Accordingly, in a coating composition containing a polysiloxane having a carbon-carbon unsaturated group and hydrosilyl group capable of hydrosilylation reaction and a solvent, the combination with a solvent that provides good coating properties and storage stability as the composition. None of the literature describes or suggests a preferred combination.

International Publication WO2005 / 010077 Pamphlet JP 2006-160811 A

  Regarding curable coating compositions composed of a polysiloxane having a carbon-carbon unsaturated group and hydrosilyl group capable of hydrosilylation reaction and a solvent, the combination is excellent in storage stability as a composition and gives a good cured film. It was not done. However, in practice, if a protic solvent, which has been widely used for the above polysiloxanes, is used, a good film cannot be formed, and the coating composition will increase in molecular weight or gels with the passage of time after production. Was recognized. Therefore, the problem to be solved by the present invention is that a curable coating composition comprising a polysiloxane having a carbon-carbon unsaturated group and a hydrosilyl group capable of hydrosilylation reaction, and a solvent can form a good film, It is to give a combination having excellent storage stability as a composition.

  In the curable coating composition comprising the polysiloxane represented by the general formula (1) and a solvent, a solvent having no hydroxyl group in the main component composition (main solvent) of the solvent and having a boiling point of 80 to 130 ° C. When used, the present invention was completed by finding that the curable coating composition was excellent in storage stability and could form a uniform and flat cured film.

〔式中、Ａはヒドロシリル化反応可能な炭素−炭素不飽和基を有する炭素数２〜１０の有機基であり、Ｒ¹は炭素数１〜２０のアルキレン基、炭素数６〜２０の２価の芳香族基、または炭素数３〜２０の２価の脂環族基から選択される少なくとも１種であり、ｎは０または１であり、Ｒ²は水素原子、炭素数１〜１０のアルキル基、またはヒドロシリル化反応可能な炭素−炭素不飽和基を有する炭素数２〜１０の有機基（１分子中のＲ²は同一でも異なっていてもよい。）であり、Ｒ³は水素原子、炭素数１〜１０のアルキル基、またはヒドロシリル化反応可能な炭素−炭素不飽和基を有する炭素数２〜１０の有機基であり、Ｒ⁴は水素原子、炭素数１〜１０のアルキル基、またはヒドロシリル化反応可能な炭素−炭素不飽和基を有する炭素数２〜１０の有機基（１分子中のＲ⁴は同一でも異なっていてもよい。）であり、Ｒ⁵は炭素数１〜６のアルキル基であり、ｖおよびｚは正の数であり、ｗ、ｘおよびｙは０または正の数であり、ｗ、ｘおよびｙのうち少なくとも１つは正の数であり、０≦ｘ／（ｖ＋ｗ）≦２であり、０≦ｙ／（ｖ＋ｗ）≦２であり、０．０１≦ｚ／（ｖ＋ｗ＋ｘ＋ｙ）≦１である。但し、ｗ＝０のとき、Ｒ²、Ｒ³およびＲ⁴の少なくともいずれか１つはヒドロシリル化反応可能な炭素−炭素不飽和基を有する炭素数２〜１０の有機基である。〕

[Wherein, A is an organic group having 2 to 10 carbon atoms having a carbon-carbon unsaturated group capable of hydrosilylation reaction, R ¹ is an alkylene group having 1 to 20 carbon atoms, and a divalent group having 6 to 20 carbon atoms. Or at least one selected from divalent alicyclic groups having 3 to 20 carbon atoms, n is 0 or 1, R ² is a hydrogen atom, alkyl having 1 to 10 carbon atoms Or an organic group having 2 to 10 carbon atoms having a carbon-carbon unsaturated group capable of hydrosilylation reaction (R ^{2 in} one molecule may be the same or different), R ³ is a hydrogen atom, An alkyl group having 1 to 10 carbon atoms, or an organic group having 2 to 10 carbon atoms having a carbon-carbon unsaturated group capable of hydrosilylation reaction, and R ⁴ is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or 2 carbon atoms having a carbon-carbon unsaturated group capable of hydrosilylation reaction -10 organic groups (R ^{4 in} one molecule may be the same or different), R ⁵ is an alkyl group having 1 to 6 carbon atoms, v and z are positive numbers, and w , X and y are 0 or a positive number, at least one of w, x and y is a positive number, 0 ≦ x / (v + w) ≦ 2, and 0 ≦ y / (v + w) ≦ 2 and 0.01 ≦ z / (v + w + x + y) ≦ 1. However, when w = 0, at least one of R ² , R ³ and R ^{4 is} a C 2-10 organic group having a carbon-carbon unsaturated group capable of hydrosilylation reaction. ]

  That is, this invention provides the curable coating composition which is excellent in storage stability, and can form a uniform and smooth cured film, and its cured film.

  The curable coating composition of the present invention has excellent storage stability and can be stored without causing gelation for 1 month or more at room temperature. Further, the curable coating composition according to the present invention is excellent in coating property and can provide a uniform and smooth cured film. This is particularly suitable for application by spin coating. Furthermore, the cured film by the curable coating composition of this invention is excellent also in heat resistance.

Hereinafter, preferred embodiments of the curable coating composition and the cured film of the present invention will be described in detail, but the present invention is not limited to these embodiments.
<Curable coating composition>
The curable coating composition of the present invention comprises polysiloxane and a solvent.
The polysiloxane in the present invention is represented by the general formula (1).

[Wherein, A is an organic group having 2 to 10 carbon atoms having a carbon-carbon unsaturated group capable of hydrosilylation reaction, R ¹ is an alkylene group having 1 to 20 carbon atoms, and a divalent group having 6 to 20 carbon atoms. Or at least one selected from divalent alicyclic groups having 3 to 20 carbon atoms, n is 0 or 1, R ² is a hydrogen atom, alkyl having 1 to 10 carbon atoms Or an organic group having 2 to 10 carbon atoms having a carbon-carbon unsaturated group capable of hydrosilylation reaction (R ^{2 in} one molecule may be the same or different), R ³ is a hydrogen atom, An alkyl group having 1 to 10 carbon atoms, or an organic group having 2 to 10 carbon atoms having a carbon-carbon unsaturated group capable of hydrosilylation reaction, and R ⁴ is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or 2 carbon atoms having a carbon-carbon unsaturated group capable of hydrosilylation reaction -10 organic groups (R ^{4 in} one molecule may be the same or different), R ⁵ is an alkyl group having 1 to 6 carbon atoms, v and z are positive numbers, and w , X and y are 0 or a positive number, at least one of w, x and y is a positive number, 0 ≦ x / (v + w) ≦ 2, and 0 ≦ y / (v + w) ≦ 2 and 0.01 ≦ z / (v + w + x + y) ≦ 1. However, when w = 0, at least one of R ² , R ³ and R ^{4 is} a C 2-10 organic group having a carbon-carbon unsaturated group capable of hydrosilylation reaction. ]

In the above general formula (1), v, w, x, y and z mean the average value of the ratio of the number of each structural unit contained in one molecule of polysiloxane. v and z are positive numbers, w, x and y are 0 or a positive number, and at least one of w, x and y is a positive number.
In the said General formula (1), v becomes like this. Preferably it is 5-100, More preferably, it is 6-80, More preferably, it is 7-60, Most preferably, it is 8-40.

  In the said General formula (1), A is a C2-C10 organic group which has a carbon-carbon unsaturated bond which can be hydrosilylated. The organic group A is not particularly limited as long as it is a functional group having a carbon-carbon double bond or triple bond capable of hydrosilylation reaction. Specific examples thereof are vinyl group, orthostyryl group, methacrylyl group, parastyryl group, acryloyl group, methacryloyl group, acryloxy group, methacryloxy group, 1-propenyl group, 1-butenyl group, 1-pentenyl group, 3-methyl-1 Examples include -butenyl group, phenylethenyl group, ethynyl group, 1-propynyl group, 1-butynyl group, 1-pentynyl group, 3-methyl-1-butynyl group, phenylbutynyl group and the like. When the polysiloxane of the present invention contains two or more organic groups A, the organic groups A in one molecule may be the same as or different from each other. As the organic group A, a vinyl group having a low carbon number and a reactive parastyryl group are preferable because raw materials are easily obtained. When the number of carbon atoms is small, the polysiloxane cured product has a large proportion of inorganic components and leads to excellent heat resistance.

In the general formula (1), R ¹ is an alkylene group having 1 to 20 carbon atoms (a divalent aliphatic group), a divalent aromatic group having 6 to 20 carbon atoms, or a divalent having 3 to 20 carbon atoms. Of the alicyclic group. Examples of the alkylene group having 1 to 20 carbon atoms include a methylene group, an ethylene group, an n-propylene group, an i-propylene group, an n-butylene group, and an i-butylene group. Examples of the divalent aromatic group having 6 to 20 carbon atoms include a phenylene group and a naphthylene group. Examples of the divalent alicyclic group having 3 to 20 carbon atoms include a divalent hydrocarbon group having a norbornene skeleton, a tricyclodecane skeleton, or an adamantane skeleton.

In the general formula (1), n is 0 or 1. Since the heat resistance of the cured film is higher when the number of carbon atoms is smaller, n = 0 is preferable.
In the said General formula (1), w becomes like this. Preferably it is 0-40, More preferably, it is 0-30, More preferably, it is 0-20, Most preferably, it is 0-10.

In the general formula (1), R ² is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an organic group having 2 to 10 carbon atoms having a carbon-carbon unsaturated bond capable of hydrosilylation reaction. Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group. These may be either aliphatic groups or alicyclic groups, and may be either linear or branched. The organic group having 2 to 10 carbon atoms having a carbon-carbon unsaturated bond capable of hydrosilylation reaction is not particularly limited as long as it is a functional group having a carbon-carbon double bond or triple bond capable of hydrosilylation reaction. , Vinyl group, orthostyryl group, methstyryl group, parastyryl group, acryloyl group, methacryloyl group, acryloxy group, methacryloxy group, 1-propenyl group, 1-butenyl group, 1-pentenyl group, 3-methyl-1-butenyl group, Examples include phenylethenyl group, ethynyl group, 1-propynyl group, 1-butynyl group, 1-pentynyl group, 3-methyl-1-butynyl group, phenylbutynyl group and the like. R ^{2 in} one molecule may be the same type or a combination of two or more different types. R ² is preferably a hydrogen atom, a methyl group or a vinyl group because it has a small number of carbon atoms and the polysiloxane cured product is excellent in heat resistance.

In the said General formula (1), x becomes like this. Preferably it is 0-40, More preferably, it is 0-30, More preferably, it is 0-20, Most preferably, it is 0-10.
In the general formula (1), R ³ is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an organic group having 2 to 10 carbon atoms having a carbon-carbon unsaturated bond capable of hydrosilylation reaction. Specific examples of the alkyl group include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, etc., linear, branched or cyclic But it doesn't matter. The carbon-carbon unsaturated bond group capable of hydrosilylation reaction is not particularly limited as long as it is a functional group having a carbon-carbon double bond or triple bond capable of hydrosilylation reaction. Vinyl group, orthostyryl group, metastyryl Group, parastyryl group, acryloyl group, methacryloyl group, acryloxy group, methacryloxy group, 1-propenyl group, 1-butenyl group, 1-pentenyl group, 3-methyl-1-butenyl group, phenylethenyl group, ethynyl group, 1 Examples include -propynyl group, 1-butynyl group, 1-pentynyl group, 3-methyl-1-butynyl group, phenylbutynyl group and the like. R ^{3 in} one molecule may be the same type or a combination of two or more different types. R ³ is preferably a hydrogen atom or a vinyl group because it can participate in the curing reaction of polysiloxane, has a small number of carbon atoms, and the polysiloxane cured product has excellent heat resistance.

In the general formula (1), R ⁴ is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an organic group having 2 to 10 carbon atoms having a carbon-carbon unsaturated bond capable of hydrosilylation reaction. Specific examples of the alkyl group include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, etc., linear, branched or cyclic But it doesn't matter. The organic group having 2 to 10 carbon atoms having a carbon-carbon unsaturated bond capable of hydrosilylation reaction may be any functional group having a carbon-carbon double bond or triple bond capable of hydrosilylation reaction. Vinyl group, orthostyryl group, methacrylyl group, parastyryl group, acryloyl group, methacryloyl group, acryloxy group, methacryloxy group, 1-propenyl group, 1-butenyl group, 1-pentenyl group, 3-methyl-1-butenyl group, phenyl Examples include ethenyl group, ethynyl group, 1-propynyl group, 1-butynyl group, 1-pentynyl group, 3-methyl-1-butynyl group, phenylbutynyl group and the like. R ^{4 in} one molecule may be the same type or a combination of two or more different types. R ⁴ is preferably a hydrogen atom, a methyl group or a vinyl group because of good reactivity and a small number of carbon atoms, and a methyl group is particularly preferred from the viewpoint of easy handling of raw materials and intermediate products.

In the said General formula (1), y becomes like this. Preferably it is 0.1-50, More preferably, it is 0.5-30, More preferably, it is 1-20, Most preferably, it is 2-10.
In the general formula (1), R5 is an alkyl group having 1 to 6 carbon atoms, and specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group.

In the said General formula (1), z becomes like this. Preferably it is 0.1-20, More preferably, it is 0.2-10, More preferably, it is 0.3-8, Most preferably, it is 0.5-5.
In the general formula (1), a preferable relationship between v, w and x is 0 ≦ x / (v + w) ≦ 2, more preferably 0 ≦ x / (v + w) ≦ 1, and further preferably 0 ≦. x / (v + w) ≦ 0.7, particularly preferably 0 ≦ x / (v + w) ≦ 0.5. When x / (v + w) is too large, the heat resistance of the heat-cured product in the absence of a catalyst tends to decrease.

  The preferred relationship between v, w and y is 0 ≦ y / (v + w) ≦ 2, more preferably 0 ≦ y / (v + w) ≦ 1, and still more preferably 0 ≦ y / (v + w) ≦ 0. 7, particularly preferably 0 ≦ y / (v + w) ≦ 0.4. When y / (v + w) is too large, the heat resistance of the heat-cured product in the absence of a catalyst tends to decrease.

Also, the preferred relationship between v, w, x, y and z is 0.01 ≦ z / (v + w + x + y) ≦ 1, more preferably 0.02 ≦ z / (v + w + x + y) ≦ 0.5, especially Preferably, 0.03 ≦ z / (v + w + x + y) ≦ 0.3. When z / (v + w + x + y) is too small, the thermosetting property in the absence of a catalyst tends to be lowered. On the other hand, when z / (v + w + x + y) is too large, the storage stability of the polysiloxane tends to decrease, and the heat resistance of the heat-cured product tends to decrease.
However, when w = 0, at least one of R ² , R ³ and R ^{4 is} a C 2-10 organic group having a carbon-carbon unsaturated group capable of hydrosilylation reaction.

  Polysiloxane satisfying the above conditions for v, w, x, y and z in the general formula (1) has a low viscosity, excellent handling workability, and forms a uniform, smooth and excellent heat-resistant coating film. .

  The polysiloxane used in the present invention is preferably one having a number average molecular weight in the range of 300 to 30,000 because it is easily dissolved in a solvent, the viscosity of the composition is easy to handle, and storage stability is good. The number average molecular weight is more preferably from 500 to 15000, further preferably from 700 to 10000, particularly preferably from 1000 to 5000. The number average molecular weight is determined by GPC (gel permeation chromatograph), for example, using GL-A130-S (porous microspherical polymer gel) manufactured by Hitachi Chemical Co., Ltd. as the column and toluene as the eluent. It can be determined using polystyrene as the material.

  The polysiloxane used in the present invention is preferably liquid at 25 ° C. The viscosity measured with an E-type viscometer at 25 ° C. is preferably 30000 mPa · s or less, more preferably 10000 mPa · s or less, still more preferably 5000 mPa · s or less, and 3000 mPa · s or less. It is particularly preferred. However, the lower limit of the viscosity is usually 1 mPa · s.

  The main solvent in the present invention is characterized by not containing a hydroxyl group and having a boiling point of 80 to 130 ° C. The main solvent means a solvent occupying a ratio of 51 wt% or more with respect to the weight of all the solvents. Originally, siloxane polymers are known to be difficult to dissolve in nonpolar solvents, and as disclosed in Patent Document 2, it is possible to use protic solvents such as butanol, ethyl lactate, propylene glycol monopropyl ether and the like. Although it has become common knowledge, in the polysiloxane used in the present invention, if the main solvent contains a hydroxyl group, the molecular weight of the polysiloxane increases during storage, the entire coating composition gels, There was an unexpected phenomenon that would cause rashes.

  On the other hand, in the composition of the present invention, increase in molecular weight and gelation hardly occur, and not only the storage stability is excellent, but also the uniformity of the cured film is excellent. A possible reason for this is that the polysiloxane used in the composition of the present invention has a structure having a carbon-carbon unsaturated bond, and it is more soluble and uniform to use a main solvent that does not contain a hydroxyl group. Good. Further, as a result of the main solvent having a specific boiling point, it is considered that this is a cause of a special effect that a cured film having excellent coating and drying properties and high smoothness can be obtained.

The main solvent preferably has a low water content and / or a low dielectric constant. Low moisture content and low relative dielectric constant mean that the conventional technology, “a solvent having a hydroxyl group and high polarity” is the opposite physical property, so the moisture content is low. When the main solvent having a low relative dielectric constant is selected, the action is the same as that of the main solvent having no hydroxyl group. The moisture content mentioned here is a weight-based moisture content u (%), and u is defined by the formula (2).
u = W _W / (W _S + W _W ) × 100 (2)

In the formula (2), W _S is the weight of the solvent not containing water, and W _W is the weight of the water contained in the solvent. The lower the moisture content, the better the storage stability of the curable coating composition. Therefore, the preferred moisture content u is less than 10%, more preferably less than 5%, more preferably less than 1%, especially Preferably it is less than 0.1%. Since a solvent having a water content of 0% does not exist in the atmosphere or is difficult to obtain, the preferred lower limit is 1 ppm or more. The water content of the solvent can be easily measured by a known method such as Karl Fischer titration.

The relative dielectric constant εr is defined by Equation (3) based on JIS C 2101: 1999.

εr = (capacitance F between the electrodes when the sample is filled) / (capacitance F between the electrodes without the sample) (3)

The lower the relative dielectric constant, the better the storage stability of the curable coating composition, but since there is no solvent having a relative dielectric constant = 1, the preferred relative dielectric constant is greater than 1 and 15 or less.

  When a proton solvent containing a hydroxyl group is used as the main solvent, the storage stability is remarkably lowered. Therefore, preferred are hydrocarbon solvents, ketone solvents, ester solvents, and ether solvents, specifically normal octane. (N-octane), methyl isobutyl ketone, toluene, normal propyl acetate, methylcyclohexane, normal heptane, isopropyl acetate, cyclohexane, methyl ethyl ketone and the like can be exemplified. Among these, normal octane, methyl isobutyl ketone, and toluene are more preferable, and normal octane is particularly preferable.

  The solvent used in the present invention may be a mixed solvent of a main solvent and at least one sub solvent. If a mixed solvent is used, the evaporation rate of the solvent can be adjusted, and as a result, the film thickness can be adjusted. Any solvent may be used as long as it can be mixed with the main solvent, but a solvent that dissolves the polysiloxane used in the present invention is preferable. Examples thereof include aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, chlorine. Examples thereof include various organic solvents such as fluorinated hydrocarbon solvent, alcohol solvent, ether solvent, amide solvent, ketone solvent, ester solvent, cellosolve solvent and the like. In order to control the drying time of the curable coating composition, it is preferable to use a secondary solvent having a boiling point that is lower by 10 ° C. or higher than the boiling point of the main solvent.

The concentration D _P (%) of the polysiloxane in the curable coating composition of the present invention is not particularly limited, but is preferably 1 to 95%. More preferably, it is 3 to 50%.
The polysiloxane concentration D _P (%) is defined by the formula (4).
D _P = W _P / (W _P + W _S ) × 100 (4)

In the formula (4), W _P is the weight (g) of polysiloxane, and W _S is the weight (g) of the solvent.

The curable coating composition of the present invention comprises a polysiloxane represented by the general formula (1) and a solvent, but other components can be used in combination as long as the effects of the present invention are not hindered.
For example, a leveling agent, a wetting agent, a fungicide, a dispersant, an antibacterial agent, a viscosity modifier, a matting agent, a pigment, etc., which are generally known as those that may be added to compositions used for coating applications These additives may be used in combination, and the blending amount thereof is arbitrary, but it is preferably about 1 to 100% by mass with respect to the coating composition of the present invention.

  As an example of the additive, a surface tension adjusting agent can be used, and fluorine-based, silicone-based, non-ionic, and the like can be used. By adding these surface tension modifiers, the wettability to the base material is improved, and the leveling property of the liquid film formed on the base material is improved, thereby preventing the occurrence of crushing and the occurrence of distorted skin. Can do.

Further, a catalyst that promotes hydrosilylation can be added. Examples of the hydrosilylation catalyst include simple substances of Group 8 to Group 10 metals such as cobalt, nickel, ruthenium, rhodium, palladium, iridium, and platinum, organometallic complexes, metal salts, and metal oxides. Usually, a platinum-based catalyst is used. Platinum catalysts include cis-PtCl ₂ (PhCN) ₂ , platinum carbon, platinum complex coordinated with 1,3-divinyltetramethyldisiloxane (Pt (dvs)), platinum vinylmethyl cyclic siloxane complex, platinum carbonyl Vinylmethyl cyclic siloxane complex, tris (dibenzylideneacetone) diplatinum, chloroplatinic acid, bis (ethylene) tetrachlorodiplatinum, cyclooctadienedichloroplatinum, bis (cyclooctadiene) platinum, bis (dimethylphenylphosphine) dichloroplatinum And tetrakis (triphenylphosphine) platinum.

  Of these, platinum complexes (Pt (dvs)) coordinated with 1,3-divinyltetramethyldisiloxane, platinum vinylmethyl cyclic siloxane complexes, and platinum carbonyl / vinylmethyl cyclic siloxane complexes are particularly preferable. Ph represents a phenyl group. The more the catalyst is used, the faster the curing is. On the other hand, the smaller the amount, the better the storage stability of the curable coating composition, so 0.1 mass ppm to 1000 mass with respect to the amount of polysiloxane. It is preferably ppm, more preferably 0.5 to 100 ppm by mass, and still more preferably 1 to 10 ppm by mass.

  In the case of using a catalyst for hydrosilylation reaction, a hydrosilylation reaction inhibitor may be added in order to suppress gelation and improve storage stability of the polysiloxane to which the catalyst is added. Examples of hydrosilylation reaction inhibitors include methylvinylcyclotetrasiloxane, acetylene alcohols, siloxane-modified acetylene alcohols, hydroperoxides, hydrosilylation reaction inhibitors containing nitrogen atoms, sulfur atoms, or phosphorus atoms. .

  The curable coating composition of the present invention preferably has a viscosity measured with an E-type viscometer at 25 ° C. of 10,000 mPa · s or less, more preferably 1000 mPa · s or less. However, the lower limit of the viscosity is usually 0.1 mPa · s.

Next, the process of forming a coating film on the substrate will be described.
As a base material on which a cured polysiloxane film can be formed, any structure having a material and shape capable of forming a coating film by coating can be used. However, when using a substrate having low heat resistance, the upper limit of the polysiloxane curing temperature is a temperature that the substrate can withstand.

  The constituent material of the base is usually an inorganic material, an organic material, or a combination thereof. Preferred materials include metals, alloys, ceramics, wood, plastics and the like. In addition, the shape includes a sheet, a plate, a cube, a rectangular parallelepiped, a pyramid, a cone, a linear body (straight line, curved line, etc.), an annular body (circular shape, polygonal shape, etc.), a regular shape body such as a tube, a sphere, irregularities, grooves And an indefinite shape having through holes, corners, and the like. Specific examples include plate glass, silicon wafers, plastics processed into various shapes, building materials, metals processed into various shapes, and the like. Further, there is no limitation on the size of these materials.

  As the coating method, a known method can be applied, and a coating film is formed on the surface of the substrate by distilling off the solvent by a known volatilization method such as air drying, heating, or decompression. Known coating methods include spin coating, dip coating, bar coating, flow coating, spray coating, roll coating, and the like. For producing a uniform thin film on a small area plane such as a wafer, spin coating is used. Is particularly preferred.

  Curing of the coating film may be performed in air or in an inert gas atmosphere such as nitrogen gas, regardless of the presence or absence of a catalyst. However, while the alkoxysilyl group is present in the polysiloxane, it is preferable that the atmosphere contains water to such an extent that the alkoxysilyl group can be hydrolyzed. If it is in the air, it can be cured sufficiently because it contains water to the extent that the alkoxysilyl group can undergo a hydrolysis reaction. In the present invention, it is preferable to perform the first stage curing in the air and the second stage curing in the air or in an inert gas atmosphere.

  The curing temperature is not particularly limited, but when the coating film is thick, for example, when the film is thicker than 3 μm, cracking is likely to occur when the curing temperature is higher than 100 ° C. Conversely, when the coating film is thin, for example, when the film is thinner than 500 nm No cracks occur even when heated to 800 ° C. or higher. In addition to volatilization of the solvent and volatile components due to thermal curing, a hydrosilylation reaction occurs between the hydrosilyl group and the hydrosilylatable carbon-carbon unsaturated group, and a cross-linking bond between Si—C—C—Si is generated. For this reason, the cured film has a very high heat resistance.

  The thickness of the obtained coating film can be calculated by using an ellipsometer, a prism coupler, a crystal oscillator type film thickness meter, or the like. Although the range of the film thickness is not particularly limited, it is generally applied by spin coating if it is less than 1 μm, and other coating methods are generally used if it is 1 μm or more.

  The numerical value of the surface roughness as an evaluation of the smoothness of the cured film can be expressed by the arithmetic average surface roughness Ra defined in JIS B 0601 (1994). Ra is a value obtained by extracting a reference length from the roughness curve in the direction of the average line, summing the absolute values of deviations from the average line of the extracted portion to the measurement curve, and averaging the values. It can be measured and calculated by such as. As a cured film obtainable by the curable coating composition of the present invention, the arithmetic average surface roughness Ra is preferably less than 50 nm. More preferably, it is less than 10 nm. Particularly preferably, it is less than 5 nm.

<Synthesis Example 1>
A 1000 ml four-necked flask was equipped with a magnetic rotor, a dropping funnel, a reflux condenser, and a thermometer, and a nitrogen stream was passed through the system. Here, 147.84 g (900 mmol) of triethoxysilane, 44.47 g (300 mmol) of trimethoxyvinylsilane, 40.30 g (300 mmol) of 1,1,3,3-tetramethyldisiloxane, 144.24 g of 2-propanol, 216 of xylene .36 g was weighed and the reaction system was put in a nitrogen atmosphere. A mixture of 65.92 g of 1.59% hydrochloric acid and 72.12 g of 2-propanol was stirred and gradually added at room temperature from the dropping funnel. After completion of dropping, the reaction solution was allowed to stand at room temperature for 18 hours.

  Next, volatile components including water are distilled off from the reaction solution under reduced pressure (temperature: 23 ° C. to 60 ° C., pressure: 52 to 1 mmHg), and a slightly light yellow liquid (hereinafter referred to as “polysiloxane (P1)”). .) 93.7 g was obtained. The number average molecular weight (Mn) of this polysiloxane (P1) measured by GPC was 1800. Moreover, it was 700 mPa * s when the viscosity in 25 degreeC was measured with the E-type viscosity meter.

なお、Ｍｎは数平均分子量を示し、Ｖｉはビニル基、Ｍｅはメチル基、Ｅｔはエチル基、ｉＰｒはイソプロピル基を示す。 Table 1 shows the approximate composition (molar ratio) of the silicon compound and the physical properties of the resulting polysiloxane.

Mn represents a number average molecular weight, Vi represents a vinyl group, Me represents a methyl group, Et represents an ethyl group, and iPr represents an isopropyl group.

For example, polysiloxane (P1) is measured for 1H-NMR (proton nuclear magnetic resonance spectrum) in a C ₆ D ₆ (heavy benzene) solvent. And the obtained measured value is analyzed as follows. That is, a signal with a chemical shift δ (ppm) of −0.2 to 0.6 is based on the structure of Si—CH ₃ , and a δ (ppm) of 0.9 to 1.5 is (OCH (CH ₃ ) ₂ , and _{OCH 2 CH 3), δ (} ppm) is from 3.5 to 4.1 is _{OCH 2 CH 3, δ (ppm} ) is from 4.1 to 5.5 is _{OCH (CH 3) 2, Si} -H, 5 Since .7 to 6.4 are considered to be based on CH = CH ₂ , simultaneous equations relating to the side chains can be established from the respective integrated signal intensity values. As for the structural units D and T, since it is known that the charged monomer is incorporated into the polysiloxane almost as it is, from the charged value of each monomer and the NMR measurement value, the mole of each structural unit contained in the polysiloxane is determined. The ratio was determined.

  If there is a molar ratio of each structural unit contained in the polysiloxane and a value of the number average molecular weight Mn of the polysiloxane, each structural unit per molecule of the polysiloxane can be calculated in average number units, so that per molecule Table 2 shows the average number contained in.

  About the synthesis examples 2-5, the raw material monomer as described in the synthesis example 1 was changed partially, or it synthesize | combined by adding another monomer. In the same manner as in Synthesis Example 1, the amounts of silicon compounds prepared in Synthesis Examples 2 to 5 and the molar ratios of the structural units based on NMR measurement and the above physical properties are shown in Table 1. Mn and the moles of each structural unit shown in Table 1 From the ratio, the average number of each structural unit contained per molecule of polysiloxane was determined and shown in Table 2.

なお、Ｖｉはビニル基、Ｍｅはメチル基、Ｅｔはエチル基、ｉＰｒはイソプロピル基を示す。

Vi represents a vinyl group, Me represents a methyl group, Et represents an ethyl group, and iPr represents an isopropyl group.

  The uniformity and smoothness of the coating film obtained are evaluated by changing the angle of the base material so that the reflection of the coating film can be best seen, and the radial streaks called striations and the coating film called Yuzu skin. The presence / absence of dents was examined, and the results were summarized in Table 3 as the evaluation of ◯ when uniform and smooth ones were found, and when x and non-uniform portions such as dents were found.

  In addition, the numerical value of the surface roughness avoids the above-mentioned non-uniform portion, selects a portion that is visually smooth and uniform, and is defined in JIS B 0601 (1994) in a 10 μm × 10 μm region using a scanning probe microscope. Arithmetic average surface roughness Ra was measured and the results are summarized in Table 3.

The storage stability of the curable coating composition was evaluated by the following method. Constant temperature maintained within a temperature range of 23 ° C. plus or minus 2 ° C. and a relative humidity of 50% plus or minus 5% in a state where the solvent is not evaporated as much as possible by placing the curable composition to be evaluated in a glass sample bottle with a lid. It was stored in a constant humidity room for 1 month, and the weight average molecular weight (Mw) at the start and after 1 month was measured by measuring by GPC (gel per emission chromatography). As a criterion for evaluation, a value obtained by dividing Mw after storage for one month by Mw at the start is referred to as “change rate of weight average molecular weight D _M ”, and when the value is less than 5, storage stability is good. On the other hand, on the contrary, those having a weight average molecular weight change rate of 5 or more, or gelled within one month, that is, those that could not maintain the liquid state were judged to have poor storage stability. The evaluation results are shown in Table 3.

  As the solvent used in the following examples, a commercially available solvent was used, and the water content was measured by Karl Fischer titration before use. The water content (ppm by mass) of each solvent is summarized in Table 3.

<Example 1>
Using the polysiloxane (P1) obtained in Synthesis Example 1 and using n-octane as the solvent, 1 g of the resin is dissolved in 1 g of the solvent so that the polysiloxane concentration D _P = 50%. A coating composition was obtained. The viscosity of the coating composition after passing through a 0.2 μm filter was 5 mPa · s at 25 ° C. The silicon wafer was coated using a spin coater to obtain a film. As a detailed procedure of the spin coating, after rotating at 200 rpm for 2 seconds, 1500 rotation for 8 seconds. The coated film was heated in a dryer at 150 ° C. for 2 hours to obtain a cured film. From the accurate weight measurement before and after film formation, the average film thickness was calculated to be 3 μm.
Since the obtained cured film was completely uniform and smooth by visual observation, an arbitrary surface was selected and Ra was measured.

  In order to evaluate the heat resistance of the cured coating, the above coating was placed in an electric furnace together with a silicon wafer, heated at 150 ° C. for 6 hours, and then taken out after cooling. However, no cracks were observed.

The storage stability of the curable coating composition was evaluated by placing 5 g of the curable coating composition in a glass sample bottle with a lid of 9 ml, a temperature of 23 ° C. plus or minus 2 ° C., a relative humidity of 50% plus or minus 5%. The sample was stored for 1 month in a constant temperature and humidity chamber kept within the range, and the weight average molecular weight change rate _DM was calculated.

<Example 2>
Using the polysiloxane (P1) obtained in Synthesis Example 1 and using n-octane as the solvent, 1 g of resin is dissolved in 9 g of the solvent so that the polysiloxane concentration D _P = 10%, thereby obtaining a coating solution. It was. As a detailed procedure of spin coating, after rotating at 500 rpm for 20 seconds, 2500 rotating for 30 seconds. Otherwise, a cured film was obtained in the same manner as in Example 1. The film thickness of the cured film was 250 nm as measured with an ellipsometer. Table 3 shows the results of various evaluations as in the examples. In addition, as a heat resistance test, the above film was put in an electric furnace together with a silicon wafer, heated at 800 ° C. for 6 hours, and taken out after cooling, but there was no change in appearance, and cracks were observed even when observed with an optical microscope. I couldn't.

<Example 3>
Except for using the polysiloxane (P2) obtained in Synthesis Example 2, the cured film obtained and the curable coating composition were evaluated in the same manner as in Example 2. The evaluation results are shown in Table 3. The film thickness of the cured film was 190 nm as measured with an ellipsometer. In addition, as a heat resistance test, the above film was put in an electric furnace together with a silicon wafer, heated at 800 ° C. for 6 hours, and taken out after cooling, but there was no change in appearance, and cracks were observed even when observed with an optical microscope. I couldn't.

<Example 4>
Except for using the polysiloxane (P3) obtained in Synthesis Example 3, the cured film obtained and the curable coating composition were evaluated in the same manner as in Example 2. The evaluation results are shown in Table 3. The film thickness of the cured film was 190 nm as measured with an ellipsometer. In addition, as a heat resistance test, the above film was put in an electric furnace together with a silicon wafer, heated at 800 ° C. for 6 hours, and taken out after cooling, but there was no change in appearance, and cracks were observed even when observed with an optical microscope. I couldn't.

<Example 5>
The cured film obtained and the curable coating composition were evaluated in the same manner as in Example 2 except that the polysiloxane (P4) obtained in Synthesis Example 4 was used. The evaluation results are shown in Table 3. The film thickness of the cured film was 210 nm as measured with an ellipsometer. In addition, as a heat resistance test, the above film was put in an electric furnace together with a silicon wafer, heated at 800 ° C. for 6 hours, and taken out after cooling, but there was no change in appearance, and cracks were observed even when observed with an optical microscope. I couldn't.

<Example 6>
The cured film obtained and the curable coating composition were evaluated in the same manner as in Example 2 except that the polysiloxane (P5) obtained in Synthesis Example 5 was used. The evaluation results are shown in Table 3. The film thickness of the cured film was 240 nm as measured with an ellipsometer. In addition, as a heat resistance test, the above film was put in an electric furnace together with a silicon wafer, heated at 800 ° C. for 6 hours, and taken out after cooling, but there was no change in appearance, and cracks were observed even when observed with an optical microscope. I couldn't.

<Example 7>
Except for changing the solvent from n-octane to methyl isobutyl ketone (MIBK), the cured film obtained and the curable coating composition were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 3.

<Example 8>
The cured film obtained and the curable coating composition were evaluated in the same manner as in Example 1 except that the solvent was changed from n-octane to toluene. The evaluation results are shown in Table 3.

<Comparative Example 1>
The cured film obtained and the curable coating composition were evaluated in the same manner as in Example 1 except that the solvent was changed from n-octane to 2-propanol (IPA). The evaluation results are shown in Table 3.

<Comparative Example 2>
The cured film obtained and the curable coating composition were evaluated in the same manner as in Example 1 except that the solvent was changed from n-octane to ethyl acetate. The evaluation results are shown in Table 3.

<Comparative Example 3>
The cured film obtained was evaluated and the curable coating composition was evaluated in the same manner as in Example 1 except that the solvent was changed from n-octane to 2-isopropoxypropane (DIPE). The evaluation results are shown in Table 3.

<Comparative example 4>
The cured film obtained and the curable coating composition were evaluated in the same manner as in Example 1 except that the solvent was changed from n-octane to hexane. The evaluation results are shown in Table 3.

<Comparative Example 5>
Except for changing the solvent from n-octane to xylene, the cured film obtained by the same method as in Example 1 was evaluated, and the remaining coating solution was evaluated. The evaluation results are shown in Table 3.

<Comparative Example 6>
The cured film obtained and the curable coating composition were evaluated in the same manner as in Example 1 except that the solvent was changed from n-octane to propylene glycol monomethyl ether acetate (PGMEA). The evaluation results are shown in Table 3.

<Comparative Example 7>
The cured film obtained and the curable coating composition were evaluated in the same manner as in Example 1 except that the solvent was changed from n-octane to ethyl lactate. The evaluation results are shown in Table 3.

なお、ＭＩＢＫはメチルイソブチルケトン、ＩＰＡは２−プロパノール、ＤＩＰＥは２−イソプロポキシプロパン、ＰＧＭＥＡはプロピレングリコールモノメチルエーテルアセテートの略称である。

MIBK is an abbreviation for methyl isobutyl ketone, IPA is 2-propanol, DIPE is 2-isopropoxypropane, and PGMEA is propylene glycol monomethyl ether acetate.

In Comparative Examples 1 to 4 where the boiling point of the main solvent is lower than 80 ° C., many striations were observed, and in Comparative Examples 5 to 7 where the boiling point of the main solvent was higher than 130 ° C., much yuzu skin was observed.
In Comparative Example values for Comparative Examples 2 to 6 In D _M contains no hydroxyl group within the main solvent molecules was similar to the embodiment, in which the 2-propanol having a hydroxyl group in the molecule as a main solvent in 1, the value of the change rate D _M having a weight-average molecular weight after the storage test 1 month is particularly large, in Comparative example 7 ethyl lactate having a hydroxyl group in the molecule and solvent, gelling the curable coating composition One month after the occurrence of the problem, the whole was solidified in the bottle, so the molecular weight after one month could not be measured.

  The polysiloxane curable coating composition of the present invention is useful for forming a heat-resistant cured film. The cured film obtained by the present invention has good characteristics in terms of mechanical strength such as water resistance, chemical resistance, stability, electrical insulation and scratch resistance in addition to heat resistance. It can be used as a coating or layer for articles or parts in a wide range of fields including optical functional materials and aerospace. It can be used for a passivation film, a resist film, an interlayer insulating film, etc. in a semiconductor or the like, and can also be used as various protective films.

Claims (5)

A curable coating comprising a polysiloxane represented by the general formula (1) and a solvent, containing 51% by mass or more of an organic solvent having no hydroxyl group in the molecule and having a boiling point of 80 to 130 ° C. Composition.

[Wherein, A is an organic group having 2 to 10 carbon atoms having a carbon-carbon unsaturated group capable of hydrosilylation reaction, R ¹ is an alkylene group having 1 to 20 carbon atoms, and a divalent group having 6 to 20 carbon atoms. An aromatic group, or a divalent alicyclic group having 3 to 20 carbon atoms, n is 0 or 1, and R ² is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a hydrosilylation reaction is possible. An organic group having 2 to 10 carbon atoms having a carbon-carbon unsaturated group (R ^{2 in} one molecule may be the same or different), and R ³ is a hydrogen atom, an alkyl having 1 to 10 carbon atoms. Or an organic group having 2 to 10 carbon atoms having a carbon-carbon unsaturated group capable of hydrosilylation reaction, and R ⁴ is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a carbon capable of hydrosilylation reaction C2-C10 organic group having a carbon unsaturated group (R in one molecule ⁴ may be the same or different.), R ⁵ is an alkyl group having 1 to 6 carbon atoms, v and z are positive numbers, and w, x and y are 0 or positive numbers. Yes, at least one of w, x and y is a positive number, 0 ≦ x / (v + w) ≦ 2, 0 ≦ y / (v + w) ≦ 2, and 0.01 ≦ z / ( v + w + x + y) ≦ 1. However, when w = 0, at least one of R ² , R ³ and R ^{4 is} a C 2-10 organic group having a carbon-carbon unsaturated group capable of hydrosilylation reaction. ]
The curable coating composition according to claim 1, comprising an organic solvent having a relative dielectric constant of greater than 1 and less than 15 in an amount of 51% by mass or more based on the total amount of the solvent.
The curable coating composition according to claim 1 or 2, comprising an organic solvent selected from one or more of n-octane, methyl isobutyl ketone, and toluene in an amount of 51% by mass or more based on the total amount of the solvent.
The cured film formed by thermosetting the curable coating composition in any one of Claims 1-3. A cured film having an arithmetic average surface roughness of less than 10 nm, which is formed on an article using the curable coating composition according to any one of claims 1 to 3 using a spin coat method.