JP4915930B2 - Composition for forming borazine diamine polymer thin film and method for producing borazine diamine polymer thin film - Google Patents

Description

  The present invention relates to a composition useful for forming a borazine diamine polymer thin film useful as a coating film, and a method for producing a borazine diamine polymer thin film using the composition.

  A borazine diamine polymer is a kind of organic borazine polymer. Conventionally, as organic borazine polymers, borazine amine polymers developed as precursors for producing boron nitride ceramics and borazines developed as precursors for producing boron nitride / silicon carbide ceramics.・ Many silazane polymers are known. These borazine / amine polymers and borazine / silazane polymers have an aminoborazinyl structure in which a borazine ring is bonded by an imino group (see Non-Patent Documents 1 to 3). In addition, polyvinyl borazine using vinyl borazine as a monomer has been developed as a boron nitride ceramic precursor (see Non-Patent Documents 1 and 2). In order not to leave excessive carbon components as impurities in boron nitride ceramics and boron nitride / silicon carbide ceramics produced by firing these polymers as precursors, the precursor polymers should reduce organic groups as much as possible. The molecular design has been made. These polymers have hydrolyzable and oxidizable structures, but have few organic groups as substituents that are effective in reducing reactivity with moisture and oxygen, so they are stable in the air. The nature is low. Moreover, since organic groups are reduced as much as possible, processability such as polymer solubility is low. These polymers are usually sintered in a deoxygenated and dehydrated gas as a ceramic precursor, and powder molding and melt spinning are used to form them, which makes them stable and workable in air. Since such improvements are not made and it is difficult to handle, application development using the polymer itself as a flame resistant material or a heat resistant material has hardly been performed (see Non-Patent Documents 1 to 3).

  In addition, since borazine-amine polymers are generally insoluble, they cannot often be treated as precursors for boron nitride ceramic thin films (see Non-Patent Document 1). A reaction of B-trichloroborazine and hexamethyldisilazane is known as a method for producing a soluble and thin-film borazine-amine polymer (see Non-Patent Document 4). In this method, B, which is a raw material, is known. -Trichloroborazine is not an industrially advantageous method because it is very difficult to handle due to its extremely high hydrolyzability and produces an equal amount of trimethylchlorosilane as a by-product.

  In addition, as a manufacturing method of boron nitride ceramic thin film or boron nitride / silicon carbide ceramic thin film, it is difficult to apply a solution of a polymer having low stability and workability in air, so boron trichloride, borane, diborane, Thin films have been produced by physical vapor deposition or chemical vapor deposition using borazine or the like as a boron source. However, these thin-film manufacturing methods are not industrially advantageous because they use large-scale apparatuses such as a vacuum chamber, a heat source, and a plasma source. Furthermore, these methods also have a problem that it is difficult to form a thin film on a substrate having a three-dimensionally uneven surface.

In contrast to this, the inventors have copolymerized a borazine monomer having an organic group as a substituent with hydrocarbosilane or hydropolysiloxane, thereby enabling processability such as handleability in air and solubility in a solvent. In addition to developing borazine and silicon-based polymers that are superior in heat resistance and developing applications as heat-resistant materials, thin films are produced from polymer solutions by spin coating and casting methods. Development of applications such as light transmission films has been performed (see Patent Documents 1 to 5). However, the presence of a platinum catalyst is essential for the production of a borazine / silicon-based polymer, and since only a part of the catalyst can be removed from the polymer produced, there is a problem that the catalyst component remains as an impurity. Therefore, development of a novel organic borazine-based polymer that can be produced without using a metal catalyst and a method for producing the thin film has been demanded.
ChemicalReviews, Vol. 90, 73-91 (1990) Chemtech, 29-37 (1994) "Inorganic Polymer 2", 1993 Industrial Book, Chapter 4, pages 81-94 Chemistry of Materials, Vol. 3, 88-91 (1991) Japanese Patent No. 3041424 Japanese Patent No. 3459985 Japanese Patent No. 3458157 Japanese Patent No. 3840127 Japanese Patent No. 3713536

  The present invention has been made in view of the above circumstances, and efficiently produces a polymer thin film having excellent processability such as stability in air and solubility in a solvent without using a metal catalyst. It is an object of the present invention to provide a method for performing the above.

  As a result of intensive studies to solve the above problems, the present inventors contain a reaction product of borazines having at least two BH bonds and diamines having at least two amino groups. A thin film of a borazine-diamine polymer produced by a dehydrogenative condensation reaction between the BH group of borazines and the NH group of diamines can be easily obtained by coating the solution on a substrate. Based on this knowledge, the present inventors have completed the present invention.

That is, according to the present invention, the following inventions are provided.
(1) The following general formula (1)
(Wherein R ¹ represents an alkyl group, an aryl group or an aralkyl group ) and borazines (a) represented by the following general formula (2)
(Wherein R ² represents a divalent group selected from an alkylene group, an arylene group, and an aralkylene group, which may have a substituent ), and a reaction product with a diamine (b) represented by A composition for forming a borazine / diamine-based polymer thin film, comprising:
(2) The reaction product is represented by the following general formula (3)
Wherein R ¹ represents an alkyl group, an aryl group or an aralkyl group, and R ² represents a divalent group selected from an alkylene group which may have a substituent and an aralkylene group. Wherein m is a positive integer and n is 0 or a positive integer). (1) The composition for forming a borazine-diamine polymer thin film according to (1) above.
(3) The following general formula (1)
(Wherein R ¹ represents an alkyl group, an aryl group or an aralkyl group ) and borazines (a) represented by the following general formula (2)
(Wherein R ² represents a divalent group selected from an alkylene group, an arylene group, and an aralkylene group, which may have a substituent ), and a reaction product with a diamine (b) represented by A method for producing a borazine-diamine polymer thin film, which comprises applying a solution containing a borazine onto a substrate.
(4) The reaction product is represented by the following general formula (3)
Wherein R ¹ represents an alkyl group, an aryl group or an aralkyl group, and R ² represents a divalent group selected from an alkylene group which may have a substituent and an aralkylene group. Wherein m is a positive integer and n is 0 or a positive integer). ( 3 ) The method for producing a borazine-diamine polymer thin film according to ( 3 ) above.

  Since the composition for forming a borazine diamine-based polymer thin film of the present invention is excellent in solubility in a solvent and stability in air, it is difficult to gel during production and storage. Further, in the present invention, by using the composition, a borazine-diamine polymer thin film having excellent heat resistance can be easily and safely produced without using a metal catalyst.

  The present invention uses a composition containing a reaction product of a borazine (a) having at least two BH bonds and a diamine (b) having at least two amino groups, A borazine diamine polymer thin film is formed by applying a solution of the composition onto a substrate.

In the present invention, the borazines having at least two or more B—H bonds are represented by the following general formula (1):
Are needed use in those represented is.

In the general formula (1), R ¹ represents an alkyl group, an aryl group, or an aralkyl group . Carbon number of an alkyl group is 1-12, Preferably it is 1-6. The aryl group has 6 to 20 carbon atoms, preferably 6 to 10 carbon atoms. The aralkyl group has 7 to 24 carbon atoms, preferably 7 to 12 carbon atoms.
Examples of R ¹ include alkyl groups such as methyl group, ethyl group, isopropyl group, t-butyl group, and octyl group, aryl groups such as phenyl group, naphthyl group, and biphenyl group, and aralkyl groups such as benzyl group and phenethyl group. Etc.

Have these substituents, specific examples of the borazine compound represented by the general formula (1), N, N ' , N "- trimethyl borazine, N, N', N" - tri ethyl borazine, N, N ', N ″ -Triprolborazine, N, N ′, N ″ -triphenylborazine, N, N ′, N ″ -tribenzylborazine, N, N ′, N ″ -triphenethylborazine, and the like. However, the present invention is not limited to this. One kind of borazines can be used alone, but the use of two or more kinds of borazines in combination is also included in an advantageous aspect of the present invention.

In the present invention, the diamine having at least two amino groups is represented by the following general formula (2).
Are needed use in those represented is.

In the general formula (2), R ² represents a divalent group selected from an alkylene group and an aralkylene group which may have a substituent. The alkylene group and the aralkylene group may form a ring. Carbon number of an alkylene group is 1-24, Preferably it is 1-12. The aralkylene group has 7 to 24 carbon atoms, preferably 7 to 12 carbon atoms. The aralkylene group includes an aralkylene group containing a hetero atom such as oxygen as a linking group. In addition, examples of the substituent which may be bonded to the divalent group include an alkyl group and an aralkyl group.
Examples of R ² include alkylene groups such as methylene group, ethylene group, propylene group, butylene group, hexylene group and octylene group, aralkylene groups such as phenylenemethylene group and phenyleneethylene group, and the like.

  Specific examples of diamines having these substituents and represented by the general formula (2) include ethylenediamine, 1,6-diaminohexane, 1,12-diaminododecane, 1,2-cyclohexanediamine, 1, Examples include, but are not limited to, 3-cyclohexanediamine, 1,4-cyclohexanediamine, and 1,3-diaminoadamantane. In addition, one kind of diamine can be used alone, but it is also included in an advantageous aspect of the present invention that two or more kinds of diamines may be combined.

The quantitative relationship of the raw material compounds in the reaction of the borazines (a) having at least two or more B—H bonds and the diamines (b) having at least two or more amino groups of the present invention is as follows: The molar ratio of diamines is in the range of 1: 0.1 to 10, preferably 1: 0.3 to 3.
The reaction can be carried out with or without a solvent, but when a solvent is used, various solvents other than those that react with the raw material can be used. Examples of these solvents include aromatic hydrocarbon-based, saturated hydrocarbon-based, aliphatic ether-based, aromatic ether-based solvents, and more specifically, toluene, benzene, xylene, hexane, tetrahydrofuran, diphenyl ether, and the like. Is mentioned.

  The reaction between the borazines (a) having at least two or more B—H bonds and the diamines (b) having at least two or more amino groups is generally heated to room temperature or hundreds of degrees Centigrade. It progresses easily in the state. Further, depending on the structure of the raw material, it can be cooled or heated in the range of −20 ° C. to 200 ° C. in order to reach a preferable speed. A preferable temperature is 0 ° C to 150 ° C, more preferably 10 ° C to 150 ° C.

  A borazine diamine polymer thin film containing a reaction product of borazines (a) having at least two BH bonds and diamines (b) having at least two amino groups in the present invention. The composition for forming has not only excellent solubility in a solvent but also excellent stability in the air, so that it does not gel easily during production and storage, and therefore has excellent storage stability. .

The borazine diamine polymer thin film of the present invention is a reaction product of the borazines (a) having at least two or more B—H bonds and the diamines (b) having at least two or more amino groups. It is manufactured by apply | coating the solution containing this on a board | substrate.
Application on the substrate in the present invention can be carried out regardless of the presence or absence of a solvent, but when a solvent is used, various solvents other than those that react with the compounds in the solution can be used. Examples of these solvents include aromatic hydrocarbon-based, saturated hydrocarbon-based, aliphatic ether-based, aromatic ether-based solvents, and more specifically, toluene, benzene, xylene, hexane, tetrahydrofuran, diphenyl ether, and the like. Is mentioned.

  In the present invention, as the substrate for forming the polymer thin film, various substrates and film materials such as metals, glass, silicon wafers, alumina, or polymer materials such as Teflon, polypropylene, and polyethylene terephthalate can be used.

As a coating method on the substrate in the present invention, a solution coating method used for forming a general polymer thin film, such as a spin coating method, a casting method, a dip method, and an ink jet method can be used.
Moreover, the drying after the application can be performed by heating at normal temperature in air or in an inert gas, or by heating, or can be performed under reduced pressure.

The borazine-diamine polymer thin film formed on the substrate by the method of the present invention has the following general formula (3):
It is a polymer thin film having a borazine skeleton represented by Incidentally, ^{R 1} and R ² in the formula is meant a ^{R 2} of each of the general formula (1) ^{R 1} and the general formula in (2), the same thing. Moreover, in formula, m is a positive integer, Preferably it is 1-1000, More preferably, it is 1-100. N is 0 or a positive integer, preferably 0 to 100, more preferably 0 to 20.

EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited to these Examples from the first.
Example 1
0.03 mol of ethylenediamine was dissolved in 30 mL of dry toluene, and 0.03 mol of N, N ′, N ″ -trimethylborazine was added dropwise. The obtained uniform solution was overflowed with a small amount of nitrogen gas in the reaction vessel. The mixture was heated and stirred for 3 days at 110 ° C. The obtained solution was analyzed, and the following results were obtained.

<NMR spectrum>
¹ H-NMR (C ₆ D ₆ ): δ 4.7-4.0, 3.6-3.2, 3.1-2.7, 2.4-2.0 ppm
¹³ C-NMR (C ₆ D ₆ ): δ 45.2-44.5, 43.8-43.2, 38.0, 34.5-33.7 ppm
¹¹ B-NMR (C ₆ D ₆ ): δ 30.5, 24.4, 19.0 ppm
<Infrared absorption spectrum (KBr pellet)>
3201 cm ⁻¹ , 2380 cm ⁻¹ , 1602 cm ⁻¹ , 1380 cm ⁻¹ , 1068 cm ⁻¹ , 712 cm ⁻¹
<ICP emission analysis _{(C 5 H 16 N 5 B} 3)>
B content 104% of theoretical value

Moreover, as a result of performing a thermogravimetric analysis about what concentrated the obtained solution under reduced pressure, the following result was obtained. This result shows that the thin film obtained by apply | coating this solution has heat resistance.
<Thermogravimetric analysis (heated to 990 ° C. at a heating rate of 10 ° C./min under an argon atmosphere)>
135 ° C Residual rate 90%
990 ° C Residual rate 58%

  A colorless and transparent thin film was obtained by applying 0.1 ml of the obtained solution on a glass substrate and drying in air. The thickness of the thin film measured using the Taly step was 2.1 μm.

(Example 2)
When 0.1 ml of the solution of Example 1 was applied onto a silicon substrate and formed by spin coating at a rotational speed of 2500 times / second, a transparent uniform thin film was obtained. After the thin film-coated substrate was heat-treated on a hot plate at 150 ° C. for 1 hour, the film thickness of the thin film measured using a Taly step was 1.3 μm. This thin film showed excellent heat resistance as in Example 1.

  According to the present invention, the borazine / diamine-based polymer thin film exhibits excellent thermal stability, and can be expected to be useful for a heat resistant coating material, an insulating film, a transparent film, and the like.

Claims (4)

The following general formula (1)
(Wherein R ¹ represents an alkyl group, an aryl group or an aralkyl group) and (a) represented by the following general formula (2)
(Wherein R ² represents a divalent group selected from an alkylene group, an arylene group, and an aralkylene group, which may have a substituent ), and a reaction product with a diamine (b) represented by A composition for forming a borazine / diamine-based polymer thin film, comprising: The reaction product is represented by the following general formula (3)
A borazine skeleton represented by the formula: ¹ Represents an alkyl group, an aryl group or an aralkyl group, and R ² Is a divalent group selected from an alkylene group and an aralkylene group which may have a substituent, m is a positive integer, and n is 0 or a positive integer) The composition for forming a borazine diamine-based polymer thin film according to claim 1. The following general formula (1)
(Wherein R ¹ represents an alkyl group, an aryl group or an aralkyl group) and the following general formula (2)
(Wherein R ² represents a divalent group selected from an alkylene group, an arylene group, and an aralkylene group, which may have a substituent ), and a reaction product with a diamine (b) represented by A method for producing a borazine-diamine polymer thin film, which comprises applying a solution containing a borazine onto a substrate. The reaction product is represented by the following general formula (3)
Wherein R ¹ represents an alkyl group, an aryl group or an aralkyl group, and R ² represents a divalent group selected from an alkylene group which may have a substituent and an aralkylene group. 4. The method for producing a borazine-diamine polymer thin film according to claim 3 , wherein m is a positive integer, and n is 0 or a positive integer.