JP2009149833A - Silicate polymer and its production method, and coating agent containing the silicate polymer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a silicate polymer of a high molecular weight and excellent in storage stability in the solution state, and a film obtainable from this silicate polymer suitably used as an insulating film for a semiconductor device or a gas barrier film. <P>SOLUTION: The silicate polymer comprising a repeating unit represented by the formula [3], and the like. The silicate polymer having a specific molecular structural unit, in which the weight-average molecular weight (Mw) in terms of the standard polystyrene is 500 to 100,000, and a molecular weight distribution (Mw/Mn) is in a range from 1.0 to 5.0. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a silicate polymer, a method for producing the same, and a coating agent containing the silicate polymer.

A silicate polymer composed of tetrafunctional siloxane units (Q units) can be suitably used for the following applications.
・ High-purity synthetic quartz raw material ・ High-purity silica / colloidal silica ・ Surface coating thin film material (contamination prevention, deodorization, photocatalyst retention, heat resistance, weather resistance, acid resistance, wear resistance, insulation, water repellency, hydrophilicity, conductivity Property, colorant content, antireflection, heat ray prevention)
・ Organic / inorganic hybrid materials ・ Silicone rubber cross-linking materials, adhesives ・ Adhesive dehydrators ・ Cosmetics (water repellency, powder surface treatment, pigment treatment)
・ Na elution prevention passivation film ・ Insulating film for semiconductors, low dielectric constant materials ・ Reinforcing materials / bonding materials (glass, ceramic, rock, brick, paper, ruins preservation)
・ Binder (zinc rich paint, precision casting)
・ Ceramic coating materials, hydrophilic coating materials ・ Plastic synthesis catalysts, catalyst carriers ・ Separation and purification (column materials, proteins, enzymes, food, chemical substances)

By the way, when this silicate polymer is used as a film forming material, it has been necessary to produce a high molecular weight silicate polymer because of its excellent film forming property depending on its molecular weight.
However, when a high molecular weight silicate polymer of Q unit alone is prepared by hydrolysis / condensation in a normal alcohol solvent, gelation itself may occur or the solution state does not occur. There is a problem that the storage stability is remarkably deteriorated when stored at a low temperature.

In addition, the following are mentioned as prior literature relevant to the present invention.
JP 07-278495 A JP 07-286135 A JP 07-286136 A JP 09-165451 A JP-A-10-226726

  The present invention has been made to solve the above-described problems, and has as its object to provide a silicate polymer that is a high molecular weight product and excellent in storage stability, a method for producing the silicate polymer, and a coating agent containing the silicate polymer. And

  As a result of intensive studies to achieve the above object, the present inventor obtained by gel permeation chromatography (GPC) containing a specific amount of repeating units represented by the following formulas [1] to [3] by the following method. A silicone polymer having a weight average molecular weight (Mw) in terms of standard polystyrene of 500 to 100,000 and a molecular weight distribution (Mw / Mn) of 1.0 to 5.0 is obtained, and this polymer is storage stable. As a result, the present invention has been made.

並びに下記式［３］

（式中、Ｒ¹は水素原子又は炭素数が１〜４のアルキル基である。）
で表される繰り返し単位を有し、上記式［１］で示される繰り返し単位が２０ｍｏｌ％以上、上記式［２］で示される繰り返し単位が４０ｍｏｌ％以上、上記式［３］で示される繰り返し単位が１０ｍｏｌ％以上で構成されてなることを特徴とするシリケートポリマー。
請求項２：
シリケートポリマーのゲルパーミエーションクロマトグラフィーによる標準ポリスチレン換算の重量平均分子量（Ｍｗ）が２，０００〜２０，０００であることを特徴とする請求項１記載のシリケートポリマー。
請求項３：
請求項１又は２記載のシリケートポリマーと有機溶剤を含有することを特徴とするコーティング剤。
請求項４：
有機溶剤が比誘電率の値が４以上２５以下である有機溶剤である請求項３記載のコーティング剤。
請求項５：
半導体用絶縁膜用である請求項３又は４記載のコーティング剤。
請求項６：
請求項５記載のコーティング剤から形成された、４００℃／１０分での熱質量減少率が１％以下であることを特徴とする半導体用絶縁膜。
請求項７：
ガスバリア膜用である請求項３又は４記載のコーティング剤。
請求項８：
請求項７記載のコーティング剤から形成された、水蒸気透過速度が０．０１ｇ／ｍ²／ｄａｙ以下であることを特徴とするガスバリア膜。
請求項９：
（Ａ）一般式：Ｓｉ（ＯＲ¹）₄（式中、Ｒ¹は水素原子又は炭素数が１〜４のアルキル基である。）で示されるアルキルシリケートを、（１）０．０１規定以上の無機酸水溶液を前記（Ａ）成分１ｍｏｌに対して無機酸水溶液中の水が１ｍｏｌ以上となるような量で含む炭素数が１〜３個の低級アルコール水溶液中において、前記（Ａ）成分の濃度を該低級アルコール水溶液中４０質量％以下の濃度で加水分解反応させ、（２）次いで、得られたシリケート加水分解物の低級アルコール溶液を、（Ｂ）比誘電率の値が４以上２５以下である有機溶剤の１種又は２種以上により、上記低級アルコールの含有量が１０質量％以下になるように置換することを特徴とする請求項１又は２記載のシリケートポリマーの製造方法。
請求項１０：
比誘電率の値が４以上２５以下である有機溶剤が、メチルエチルケトン、メチルイソブチルケトン、シクロペンタノン、シクロヘキサノン、ターシャリーブチルアルコール、ジアセトンアルコール、酢酸エチル、又は酢酸ブチルであることを特徴とする請求項１又は２記載のシリケートポリマーの製造方法。 Accordingly, the present invention provides the following silicate polymer and method for producing the same, and a coating agent containing the silicate polymer.
Claim 1:
The weight average molecular weight (Mw) in terms of standard polystyrene by gel permeation chromatography is 500 to 100,000, the molecular weight distribution (Mw / Mn) is in the range of 1.0 to 5.0, and the following formula [1] And formula [2]

And the following formula [3]

(In the formula, R ¹ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)
The repeating unit represented by the formula [1] is 20 mol% or more, the repeating unit represented by the formula [2] is 40 mol% or more, and the repeating unit represented by the formula [3]. Is a silicate polymer characterized by comprising 10 mol% or more.
Claim 2:
2. The silicate polymer according to claim 1, wherein the silicate polymer has a weight average molecular weight (Mw) in terms of standard polystyrene as measured by gel permeation chromatography of 2,000 to 20,000.
Claim 3:
A coating agent comprising the silicate polymer according to claim 1 or 2 and an organic solvent.
Claim 4:
The coating agent according to claim 3, wherein the organic solvent is an organic solvent having a relative dielectric constant of 4 or more and 25 or less.
Claim 5:
The coating agent according to claim 3 or 4, which is used for an insulating film for a semiconductor.
Claim 6:
An insulating film for a semiconductor formed from the coating agent according to claim 5, wherein a thermal mass reduction rate at 400 ° C./10 minutes is 1% or less.
Claim 7:
The coating agent according to claim 3 or 4, which is used for a gas barrier film.
Claim 8:
A gas barrier film having a water vapor transmission rate of 0.01 g / m ² / day or less formed from the coating agent according to claim 7.
Claim 9:
(A) An alkyl silicate represented by the general formula: Si (OR ¹ ) ₄ (wherein R ¹ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms) (1) 0.01 N or more In the lower alcohol aqueous solution having 1 to 3 carbon atoms in which the amount of water in the inorganic acid aqueous solution is 1 mol or more per 1 mol of the component (A), The lower alcohol solution of the obtained silicate hydrolyzate is subjected to hydrolysis reaction at a concentration of 40% by mass or less in the lower alcohol aqueous solution, and (B) the relative dielectric constant is 4 or more and 25 or less. The method for producing a silicate polymer according to claim 1 or 2, wherein the content of the lower alcohol is substituted with one or more of organic solvents that are 10% by mass or less.
Claim 10:
The organic solvent having a relative dielectric constant of 4 or more and 25 or less is methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, tertiary butyl alcohol, diacetone alcohol, ethyl acetate, or butyl acetate. A method for producing a silicate polymer according to claim 1 or 2.

  According to the silicate polymer of the present invention, it is possible to produce a silicate polymer having a high molecular weight and excellent storage stability in a solution state, and a film obtained from this silicate polymer is suitable as an insulating film for a semiconductor or a gas barrier film. Can be used for

The silicate polymer of the present invention has a standard polystyrene equivalent weight average molecular weight (Mw) of 500 to 100,000, particularly 2,000 to 20,000, and a molecular weight distribution (Mw / Mn) of 1.0 to 5 by GPC. The range is 0.0, and has repeating units of the following formulas [1] to [3].

Here, R ¹ defined in the above formulas [1], [2] and [3] of the present invention is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Group, propyl group, butyl group and the like, and a hydrogen atom, a methyl group and an ethyl group are preferable.

In the silicate polymer of the present invention, the repeating unit (Q4 unit) represented by the formula [1] is 20 to 50 mol%, preferably 20 to 40 mol%, and the repeating unit (Q3 unit) represented by the formula [2] is 40. -70 mol%, Preferably it is 40-60 mol%, The repeating unit (Q2 unit) shown by the said Formula [3] is comprised by 10-40 mol%, Preferably it is comprised by 15-30 mol%.
In addition, the sum total of the said Q4 unit, Q3 unit, and Q2 unit is 100 mol%.

The method for producing a silicate polymer according to the present invention is an alkyl silicate represented by (A) general formula: Si (OR ¹ ) ₄ (wherein R ¹ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms). (1) A lower alcohol having 1 to 3 carbon atoms containing an aqueous inorganic acid solution of 0.01 N or more in an amount such that the amount of water in the aqueous inorganic acid solution is 1 mol or more with respect to 1 mol of the component (A). In the aqueous solution, the concentration of the component (A) is hydrolyzed at a concentration of 40% by mass or less in the lower alcohol aqueous solution. (2) Then, the lower alcohol solution of the obtained silicate hydrolyzate is obtained as (B) The organic solvent having a relative dielectric constant of 4 or more and 25 or less is substituted with one or more organic solvents so that the content of the lower alcohol is 10% by mass or less.

In the production method of the present invention, the alkyl silicate of the component (A) is represented by the general formula: Si (OR ¹ ) ₄ . In the above formula, R ¹ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, specifically, a hydrogen atom, a methyl group, an ethyl group, or a propyl group is exemplified, and the availability and the carbon number are small. Since alkyl group tends to increase the hydrolysis rate of component (A), it is preferably a methyl group or an ethyl group. Such alkyl silicates of component (A) are generally commercially available as orthosilicates, and specific examples of component (A) include methyl orthosilicate, ethyl orthosilicate, and isopropyl orthosilicate. However, it is preferable to use methyl orthosilicate or ethyl orthosilicate since the hydrolysis rate tends to increase as the alkyl silicate having an alkyl group having a small number of carbon atoms is easily available. .

  In the production method of the present invention, first, an inorganic acid aqueous solution of 0.01 N or more is contained in an amount such that water in the inorganic acid aqueous solution is 1 mol or more with respect to 1 mol of the component (A). In the lower alcohol aqueous solution, the component (A) is subjected to a hydrolytic condensation reaction at a concentration of 40% by mass or less in the lower alcohol aqueous solution.

  In this case, the lower alcohol is not particularly limited, and examples thereof include methyl alcohol, ethyl alcohol, i-propyl alcohol, and n-propyl alcohol. After preparing the silicate polymer, the silicate polymer is solvent-substituted with the component (B). In this case, methyl alcohol or ethyl alcohol is preferred because it is desirable to have a lower boiling point.

  In the production method of the present invention, the content of the component (A) in the lower alcohol aqueous solution needs to be 40% by mass or less, preferably 5 to 30% by mass, and more preferably 5 to 20% by mass. If the content of the component (A) exceeds 40% by mass, the hydrolysis condensation rate of the component (A) can be relaxed and high molecular weight until the resulting silicate polymer is gelled can be prevented. This is because it disappears. In addition, it is possible to use a water-soluble organic solvent other than the alcohol in the lower alcohol aqueous solution as long as the object of the present invention is not impaired.

  Further, the inorganic acid that can be used in the lower alcohol aqueous solution is not particularly limited, and specific examples include hydrochloric acid, sulfuric acid, and nitric acid. Among these, hydrochloric acid is particularly preferably used. Furthermore, the aqueous solution concentration of the inorganic acid is 0.01 N or more. If the concentration is less than 0.01 N, the hydrolysis rate is slow, and it is difficult to increase the molecular weight. The upper limit of the concentration is appropriately selected, but is usually 1 standard or less. The amount of the aqueous solution added is preferably such that the amount of water in the inorganic acid aqueous solution is 1 mol or more per 1 mol of component (A). If the amount is less than 1 mol, the amount of silanol due to hydrolysis decreases, and naturally the molecular weight does not become a polymer, which is not preferable. More preferably, this amount is 2.0 to 4.0 mol per 1 mol of component (A). If this amount exceeds 4.0 mol, gelation tends to occur, and storage stability tends to deteriorate without gelation, which is not preferable.

  In the production method of the present invention, the reaction temperature during hydrolysis is not particularly limited, but for example, the reaction temperature is preferably 10 to 40 ° C. The reaction time is not particularly limited, but is preferably about 1 to 6 hours.

  Subsequently, in the production method of the present invention, the silicate polymer obtained by the hydrolysis-condensation reaction is obtained by using (B) one or two or more organic solvents having a relative dielectric constant of 4 or more and 25 or less. Substitution is performed so that the content of the lower alcohol is 10% by mass or less. This is because the silanol group in the resulting silicate polymer undergoes a condensation reaction over time in the lower alcohol solution and lowers storage stability (viscosity, gelation). It is because it discovered that a silanol group can exist stably by substituting.

  The organic solvent of component (B) is not particularly limited as long as the value of relative dielectric constant is 4 or more and 25 or less. Specifically, the organic solvent of component (B) is diethyl ether (relative dielectric constant: 4. 197), diisopropyl ether (relative permittivity: 4.49), anisole (relative permittivity: 4.33), phenetole (relative permittivity: 4.22), 1,2-dimethoxyethane (relative permittivity: 5. 50), 1,2-diethoxyethane (dielectric constant: 5.10) and other ether solvents; methyl ethyl ketone (dielectric constant: 18.51), methyl isobutyl ketone (dielectric constant: 13.11), 2 -Ketone solvents such as heptanone (relative permittivity: 9.77), cyclopentanone (relative permittivity: 16.3), cyclohexanone (relative permittivity: 18.10); ethyl acetate (relative permittivity: 6. 02), butyl acetate ( Dielectric constant: 5.01), ester solvents such as isobutyl acetate (relative dielectric constant: 5.29), diethyl sebacate (dielectric constant: 5.00); tertiary butyl alcohol (relative dielectric constant: 11.4) ), Diacetone alcohol (relative permittivity: 18.2); and other organic solvents include chloroform (relative permittivity: 4.335). Particularly preferred are methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, tertiary butyl alcohol, diacetone alcohol, ethyl acetate, butyl acetate and the like.

Furthermore, in the production method of the present invention, the solvent replacement method with the component (B) is a method of adding the component (B) after removing the alcohol under normal pressure or reduced pressure, or a component (B) in an aqueous alcohol solution. And a method of distilling off low boiling alcohol while heating under normal pressure or reduced pressure. (B) amount of the component, when the SiO ₂ equivalent amount of 1 part by weight of component (A) is preferably 5 to 50 parts by weight. If this amount is less than 5 parts by mass, the storage stability may deteriorate. Moreover, when it exceeds 50 mass parts, it is unpreferable from a cost viewpoint. At this time, the lower alcohol content in the system is substituted with the component (B) up to 10% by mass or less, preferably 5% by mass or less, and more preferably 2% by mass or less. When the content exceeds 10% by mass, a condensation reaction is caused with time, and storage stability may be lowered (increased viscosity or gelled), which is not preferable.

  In addition, the silicate polymer of the present invention is not particularly limited in use form, but can be typically used as a coating agent together with an organic solvent. As the organic solvent, an organic solvent having a relative dielectric constant of 4 or more and 25 or less can be preferably used. The concentration of the silicone polymer in this coating agent may be selected depending on the intended use, but is preferably 0.5 to 30% by mass, particularly 1 to 20% by mass, and particularly preferably 2 to 10% by mass.

  A curing catalyst may be added to the coating agent as long as the storage stability is not impaired. Specific examples include aluminum, titanium, and zirconium-based chelate catalysts. If it is a range which does not inhibit storage stability, it may be added at the time of hydrolysis, or may be added after the substitution to the component (B).

  Although the silicate polymer obtained in the present invention can be used for various applications as described in the background art, it is highly polymerized, and the resulting film has a low thermal mass reduction rate at high temperatures. The coating agent containing this can be suitably used for semiconductor insulating films such as SOG (spin-on-glass) and interlayer insulating films. The thermal mass reduction rate at a high temperature can be 1% or less, particularly 0.5% or less at 400 ° C./10 minutes.

In addition, the film obtained from the coating agent containing the silicate polymer obtained in the present invention is excellent in gas barrier properties, so that it can be suitably used as a gas barrier film for an organic EL device that needs to barrier oxygen and water vapor. Can do. In this case, for example, a plastic substrate or the like may be covered with a film obtained from the silicate polymer obtained in the present invention. The water vapor permeability of the film can be 0.01 g / m ² / day or less.

  The film thickness of the film obtained from the silicate polymer according to the present invention is not particularly limited, but is preferably in the range of 50 to 1,000 nm. Especially preferably, it is 100-500 nm. The film forming method is not particularly limited as long as it is a wet method, but a general dipping method, roll coating method, spray method, curtain flow coating method, spin coating method and the like are preferable. The curing is performed at room temperature to 150 ° C. for 30 seconds to 8 hours. In particular, when the base material is an organic resin, it is preferably performed in the range of 50 to 110 ° C. for 30 seconds to 3 hours.

  EXAMPLES Hereinafter, although a synthesis example, an Example, and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.

[Example 1]
300 g of methanol and 152 g (1.0 mol) of normal methyl silicate are added to a 2-liter four-necked flask equipped with a dropping pipe with a straight pipe, a serpentine condenser and a thermometer, and a very small flow rate is added to the system while stirring. Through nitrogen. While stirring the solution in this state, 45 g (2.5 mol) of 0.05N hydrochloric acid aqueous solution was added from a dropping tube with a straight tube. The liquid temperature rose to 41 ° C. due to heat generation. After the addition, the mixture was stirred at room temperature for 2 hours. The reaction solution was colorless and transparent. To this reaction solution, 500 g of methyl isobutyl ketone was added, an ester adapter was attached, and methanol was distilled off while heating under normal pressure. Finally, the liquid temperature was raised to 110 ° C. and methyl isobutyl ketone was added to dilute the gas chromatography to 6% to prepare a silicate polymer solution. This silicate polymer solution was diluted as it was in tetrahydrofuran to prepare a solution having a solid content mass concentration of 0.2%, and this solution was injected into gel permeation chromatography using tetrahydrofuran as a carrier solvent. The molecular weight was 2,096, the weight average molecular weight was 6,766, and the degree of dispersion was 3.229. In addition, from the ²⁹ Si-nuclear magnetic resonance spectrum analysis of this dissolved component, no Q1 unit was observed. From each integrated value, the obtained silicate polymer was a silicate polymer composed of Q4: Q3: Q2 = 30 mol%: 51 mol%: 19 mol%. In addition, when this silicate polymer solution was sealed and stored in a high-density polyethylene wide-mouth bottle at room temperature, the viscosity of the solution and the molecular weight of the dissolved component did not change when one month passed.

  The silicate polymer solution obtained in Example 1 was coated on a glass substrate by a dip method, and cured at room temperature for 1 hour, at 110 ° C. for 10 minutes, and further at 250 ° C. for 1 hour to obtain a film having a thickness of 1 μm. When the obtained film was peeled off and the thermal mass reduction rate when held at 400 ° C. for 10 minutes was measured using a thermal analysis measuring device (THERM PLUS TG8120 manufactured by Rigaku Corporation), the thermal mass reduction rate was 0.3%. Met.

The silicate polymer solution obtained in Example 1 was adjusted to a solid mass concentration of 2% with methyl isobutyl ketone, and this solution was coated on a PET substrate by dipping, and cured at room temperature for 1 hour and at 80 ° C. for 1 hour. Then, a film was formed. The film thickness was 250 nm. When this substrate was measured for water vapor transmission rate under a relative humidity of 90% using a water vapor transmission measuring device (PERMATRAN-3 / 33 manufactured by MOCON), the water vapor transmission rate was 0.01 g / m ² / day or less. (The water vapor transmission rate of the PET substrate was 5.0 g / m ² / day).

[Example 2]
300 g of methanol and 208 g (1.0 mol) of normal ethyl silicate are added to a 2 liter four-necked flask equipped with a dropping tube with a straight tube, a serpentine condenser and a thermometer, and a very small flow rate is added to the system while stirring. Through nitrogen. While stirring the solution in this state, 54 g (3.0 mol) of 0.05N hydrochloric acid aqueous solution was added from a dropping tube with a straight tube. The liquid temperature rose to 31 ° C. due to heat generation. After the addition, the mixture was stirred at room temperature for 2 hours. The reaction solution was colorless and transparent. To this reaction solution, 500 g of methyl isobutyl ketone was added, an ester adapter was attached, and methanol was distilled off while heating under normal pressure. Finally, the liquid temperature was raised to 110 ° C., and methanol was distilled off to 1.8% in area% by gas chromatography analysis. Thereafter, methyl isobutyl ketone was further added and diluted so that the solid content mass concentration became 6% to prepare a silicate polymer solution. This silicate polymer solution was diluted as it was in tetrahydrofuran to prepare a solution having a solid content mass concentration of 0.2%, and this solution was injected into gel permeation chromatography using tetrahydrofuran as a carrier solvent. The molecular weight was 2,103, the weight average molecular weight was 5,190, and the degree of dispersion was 1.889. In addition, from the ²⁹ Si-nuclear magnetic resonance spectrum analysis of this dissolved component, no Q1 unit was observed. From each integrated value, the obtained silicate polymer was a silicate polymer composed of Q4: Q3: Q2 = 22 mol%: 52 mol%: 26 mol%. Further, when this silicate polymer solution was sealed and stored in a high-density polyethylene wide-mouthed bottle at room temperature, the viscosity of the solution and the molecular weight of the dissolved component did not change after one month.

[Example 3]
A 2-liter four-necked flask equipped with a dropping tube with a straight tube, a serpentine condenser and a thermometer was added 300 g of methanol, 152 g (1.0 mol) of normal methyl silicate and 1.2 g (0.0028 mol) of diisopropyl diethyl acetoacetate titanium. ) And nitrogen was passed through the system at a very small flow rate while stirring. While stirring the solution in this state, 36 g (2.0 mol) of 0.05N hydrochloric acid aqueous solution was charged from a dropping tube with a straight tube. The liquid temperature rose to 23 ° C due to exotherm. After the addition, the mixture was stirred at room temperature for 2 hours. The reaction solution was colorless and transparent. To this reaction solution, 500 g of methyl isobutyl ketone was added, an ester adapter was attached, and methanol was distilled off while heating under normal pressure. Finally, the liquid temperature was raised to 86 ° C., and methanol was distilled off to 4.8% in area% by gas chromatography analysis. Thereafter, methyl isobutyl ketone was further added and diluted so that the solid content mass concentration became 6% to prepare a silicate polymer solution. This silicate polymer solution was diluted as it was in tetrahydrofuran to prepare a solution having a solid content mass concentration of 0.2%, and this solution was injected into gel permeation chromatography using tetrahydrofuran as a carrier solvent. The molecular weight was 2,623, the weight average molecular weight was 6,371, and the degree of dispersion was 2.815. In addition, from the ²⁹ Si-nuclear magnetic resonance spectrum analysis of this dissolved component, no Q1 unit was observed. From each integrated value, the obtained silicate polymer was a silicate polymer composed of Q4: Q3: Q2 = 36 mol%: 43 mol%: 21 mol%. In addition, when this silicate polymer solution was sealed and stored in a high-density polyethylene wide-mouth bottle at room temperature, the viscosity of the solution and the molecular weight of the dissolved component did not change when one month passed.

[Comparative Example 1]
300 g of methanol and 152 g (1.0 mol) of normal methyl silicate are added to a 2-liter four-necked flask equipped with a dropping tube with a straight tube, a serpentine condenser and a thermometer, and a very small flow rate is added to the system while stirring. Through nitrogen. While stirring the solution in this state, 45 g (2.5 mol) of 0.05N hydrochloric acid aqueous solution was added from a dropping tube with a straight tube. The liquid temperature rose to 40 ° C. due to heat generation. After the addition, the mixture was stirred at room temperature for 2 hours. The reaction solution was colorless and transparent. Methanol was removed from this reaction solution at room temperature under reduced pressure, ethanol was added, and the solid content concentration was adjusted to 6%. When this silicate polymer solution was stored tightly at room temperature in a high-density polyethylene jar, gelation occurred when 2 weeks passed.

Claims (10)

The weight average molecular weight (Mw) in terms of standard polystyrene by gel permeation chromatography is 500 to 100,000, the molecular weight distribution (Mw / Mn) is in the range of 1.0 to 5.0, and the following formula [1] And formula [2]

And the following formula [3]

(In the formula, R ¹ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)
The repeating unit represented by the formula [1] is 20 mol% or more, the repeating unit represented by the formula [2] is 40 mol% or more, and the repeating unit represented by the formula [3]. Is a silicate polymer characterized by comprising 10 mol% or more.   2. The silicate polymer according to claim 1, wherein the silicate polymer has a weight average molecular weight (Mw) in terms of standard polystyrene as measured by gel permeation chromatography of 2,000 to 20,000.   A coating agent comprising the silicate polymer according to claim 1 or 2 and an organic solvent.   The coating agent according to claim 3, wherein the organic solvent is an organic solvent having a relative dielectric constant of 4 or more and 25 or less.   The coating agent according to claim 3 or 4, which is used for an insulating film for a semiconductor.   An insulating film for a semiconductor formed from the coating agent according to claim 5, wherein a thermal mass reduction rate at 400 ° C./10 minutes is 1% or less.   The coating agent according to claim 3 or 4, which is used for a gas barrier film. A gas barrier film having a water vapor transmission rate of 0.01 g / m ² / day or less formed from the coating agent according to claim 7. (A) An alkyl silicate represented by the general formula: Si (OR ¹ ) ₄ (wherein R ¹ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms) (1) 0.01 N or more In the lower alcohol aqueous solution having 1 to 3 carbon atoms in which the amount of water in the inorganic acid aqueous solution is 1 mol or more per 1 mol of the component (A), The lower alcohol solution of the obtained silicate hydrolyzate is subjected to hydrolysis reaction at a concentration of 40% by mass or less in the lower alcohol aqueous solution, and (B) the relative dielectric constant is 4 or more and 25 or less. The method for producing a silicate polymer according to claim 1 or 2, wherein the content of the lower alcohol is substituted with one or more of organic solvents that are 10% by mass or less.   The organic solvent having a relative dielectric constant of 4 or more and 25 or less is methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, tertiary butyl alcohol, diacetone alcohol, ethyl acetate, or butyl acetate. A method for producing a silicate polymer according to claim 1 or 2.