JPH11111062A - Cross-linked polysilane composition and formed film therefrom - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a polysilane film whose mechanical characteristic, particularly fragility is improved and which has excellent solvent resistance and a shaping property by using a composition by dissolving polysilane and an organic titanium compound in an organic solvent. SOLUTION: Desirably, a structure of polysilane is expressed by a formula, and an organic titanium compound is formed of alkoxytitanate, titanium acetyl acetonate or titanium carboxylic acid salt. After this composition having excellent preserving stability is molded into a film, an organic solvent is removed, and the formation of a three-dimensional network is restrained, and a cross- linked polysilane film is obtained. Therefore, it becomes a film on which a weak point of polysilane photodissociation is removed without losing elasticity and flexibility. [In the formula, R<1> and R<2> represent hydrogen or a substitutional or nonsubstitutional aliphatic, alicyclic or aromatic univalent hydrocarbon radical. X represents a hydoxy group, an alkoxy group or a halogen atom. (0<=m<=2, and 0.1<=n<=2, and 0<p<=0.2, and 1<=m+n+p<=2.5, and 5<=q<=100000) are realized, and (q) represents an integer].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a novel crosslinkable polysilane composition and a molded film thereof.

[0002]

2. Description of the Related Art In recent years,
Polysilanes having a Si-Si bond in the main chain have attracted attention as ceramic precursor materials and various functional material materials. However, since polysilane has a hard and brittle property, it has a defect that a crack is generated or broken even by a slight strain, and it is difficult to handle, and it is difficult to apply it to various uses as a material.

In order to solve these disadvantages, Hayashida et al.
It has been found that adding and mixing a plasticizer is an advantageous solution for increasing the strength of polysilanes and improving brittleness (Japanese Patent Application No. 6-172656). However, since this method promotes photodegradability, it is suitable for applications such as lithography, but is applied to antistatic protective films that require light stability, materials for solar cells, enclosures for electromagnetic shielding, etc. Not suitable for possible materials.

Further, copolymerization of a silicon-containing monomer and an olefin monomer (H. Sakurai, JA)
m. Chem. Soc. , 1989, 111, 764.
1. However, all of these methods involve a reaction and are complicated and costly, and the brittleness of the molded product has not been sufficiently improved.

On the other hand, attempts have been made to improve the strength by crosslinking and the like (R. West, J. Organomet. Ch.).
em. , 1986, 300, 327. H. Qiu, J. et al.
Polym. Sci. , Polym. Chem. Ed.
1989, 27, 2849. JP-A-3-246548). West et al. Utilize light-irradiation of polysilane under oxygen to generate silanol and use the crosslinking by heating. However, this reaction has the disadvantage that some or all of the polysilane part is decomposed by light irradiation. have. Also, Hayase et al. (Macromolecules, 2
8, 1773 (1995)) is to improve the durability of a film by cross-linking a polysilane having a phenolic or alcoholic side group with a vapor of hydrogen chloride / formalin, or by heating a polysilane having an alkoxy side group. However, this method requires expensive and extremely difficult to synthesize phenolic or alcoholic side group polysilane, and has the drawback of gelling during synthesis or storage before film formation, In each case, it is complicated and expensive, and the brittleness of the molded product has not been sufficiently improved.

[0006] Conventionally, a highly durable glass composite material in which a polysilane is fixed in a glass component with a high crosslink density and a three-dimensional network is already known (Japanese Patent Application Laid-Open No. 5-105766; 8-29
No. 5537). In Japanese Patent Application Laid-Open No. 5-105766, a copolymer of polysilane and silicate glass is crosslinked in a network structure through a metal element containing polysilane and titanium and an oxygen atom in Japanese Patent Application Laid-Open No. 8-295537. . However, in these methods, since the three-dimensional network is formed into a ceramic shape, the durability is obtained, but there is a problem that the inherent flexibility and flexibility of the polymer are lost.

[0007] Accordingly, there has been a demand for the development of a polysilane composition which can improve the mechanical properties, especially the brittleness, and form a polysilane film having excellent solvent resistance and shapeability.

[0008]

Means for Solving the Problems and Embodiments of the Invention The present inventors have conducted intensive studies in order to meet the above-mentioned demands, and as a result, have found that ordinary side-chain groups which can be easily synthesized by a known method such as the Wurtz method. Such as the following general formula (1) (R ¹ _m R ² _n X _p Si) _q (1) (wherein R ¹ and R ² are a hydrogen atom or a substituted or unsubstituted aliphatic or alicyclic Or an aromatic monovalent hydrocarbon group, X is a hydroxy group, an alkoxy group or a halogen atom, and m is 0 ≦
m ≦ 2, n is 0.1 ≦ n ≦ 2, p is 0 <p ≦ 0.2
And a positive number satisfying 1 ≦ m + n + p ≦ 2.5,
q is an integer of 5 ≦ q ≦ 100,000. )) Together with an organotitanium compound,
By using a composition in which these are dissolved in an organic solvent, storage stability is also excellent, and by removing the organic solvent by casting the composition, formation of a three-dimensional network can be suppressed. The present inventors have found that a crosslinkable polysilane composition which can overcome a defect of polysilane photodegradability and provide a crosslinked polysilane film having excellent mechanical strength and solvent resistance can be obtained without impairing flexibility and flexibility. This is what led to the invention.

Now, the present invention will be described in further detail. The crosslinkable polysilane composition of the present invention comprises polysilane,
The main component is an organic titanium compound and an organic solvent capable of dissolving the polysilane and the organic titanium compound.

Here, as the polysilane, Si is used in the main chain.
It has a -Si bond and has one or more kinds of various organic groups, hydrogen atoms, halogen atoms, and the like in a side chain, and particularly preferably those represented by the following general formula (1).

(R ¹ _m R ² _n X _p Si) _q (1) (wherein R ¹ and R ² are a hydrogen atom or a substituted or unsubstituted aliphatic, alicyclic or aromatic monovalent hydrocarbon) A group, X is a hydroxy group, an alkoxy group or a halogen atom, and m is 0 ≦
m ≦ 2, n is 0.1 ≦ n ≦ 2, p is 0 <p ≦ 0.2
And a positive number satisfying 1 ≦ m + n + p ≦ 2.5,
q is an integer of 5 ≦ q ≦ 100,000. )

When R ¹ and R ² are unsubstituted aliphatic or alicyclic hydrocarbon groups, they have 1 to 12, preferably 1 to 8 carbon atoms, such as methyl, ethyl and propyl. Groups, butyl, pentyl, hexyl, cyclopentyl, cyclohexyl, octyl, decyl and the like. The aromatic hydrocarbon group preferably has 6 to 14 carbon atoms, more preferably 6 to 10 carbon atoms, such as phenyl, benzyl, tolyl, xylyl, and naphthyl. Further, as the substituted hydrocarbon group, those in which part or all of the hydrogen atoms of the unsubstituted hydrocarbon groups exemplified above are substituted with halogen atoms, alkoxy groups, amino groups, aminoalkyl groups, etc., for example, p-dimethyl Aminophenyl group, m-dimethylaminophenyl group and the like can be used.

X is a hydroxy group, an alkoxy group or a halogen atom, wherein the alkoxy group has 1 to 4 carbon atoms such as a methoxy group and an ethoxy group, and the halogen atom includes a chlorine atom and a bromine atom. Usually, a hydroxy group is used.

M is 0 ≦ m ≦ 2, especially 0.5 ≦ m ≦ 1,
n is 0.1 ≦ n ≦ 2, especially 0.5 ≦ n ≦ 1, and p is 0
<P ≦ 0.2, especially 0 <p ≦ 0.1, and 1 ≦
It is a number that satisfies m + n + p ≦ 2.5, particularly 1.5 ≦ m + n + p ≦ 2, and q is an integer in the range of 5 ≦ q ≦ 100,000, particularly 10 ≦ q ≦ 10,000.

X can react with a titanium compound to form a crosslinked polysilane film, thereby improving the film strength, preventing peeling from the substrate, and improving the adhesion, but the amount is too large. In addition, the stability of the composition such as gelation during storage may be reduced, and the film may be embrittled due to a reduction in the inherent flexibility and flexibility.

The above-mentioned polysilane is easily produced by subjecting the corresponding dichlorodialkylsilane or the like to a wurtz-type condensation reaction with an alkali metal. Further, if necessary, by mixing trichloroalkylsilane or tetrachlorosilane with dichlorodialkylsilane and copolymerizing the mixture, the number of crosslinking points can be increased, and the film strength and solvent resistance can be increased. After the completion of the reaction, the polysilane partially having a halogen can be converted into a polysilane having a hydroxy group or an alkoxy group by a subsequent post-treatment with water or alcohol. The molecular weight of the polysilane is preferably 300 or more in terms of styrene-equivalent weight average molecular weight. If the weight average molecular weight is lower than 300, the function derived from the Si—Si bond may not be sufficiently exhibited.

As the organic titanium compound, alkoxy titanate, titanium acetylacetonate and titanium carboxylate are preferably used. In this case, alkoxy titanates represented by the general formulas (2) and (3), titanium acetylacetonate represented by the general formula (4), and titanium carboxylate represented by the general formulas (5) and (6) Is preferred.

[0018]

Embedded image (However, R represents a monovalent aliphatic hydrocarbon group having 1 to 8 carbon atoms, and R 'represents a monovalent aliphatic hydrocarbon group having 1 to 18 carbon atoms.)

For example, R is methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl or the like;
Examples thereof include methyl, ethyl, propyl, butyl, octyl, nonyl, stearyl and the like.

Such alkoxy titanium compounds and titanium carboxylate include tetramethyl titanate, tetraethyl titanate, tetra n-propyl titanate, tetraisopropyl titanate, tetrabutoxy titanate,
Alternatively, it is commercially available as octylate titanate (for example,
Aldrich) may be used, or it may be synthesized by reacting tetrachlorotitanium with the corresponding alcohol, or by reacting two or more types of tetraalkoxytitanate with another alcohol or acetylacetonate. Oligotitanate may be used by synthesizing or adding a small amount of water by adding titanate having an alkoxy group or a small amount of water.

Among them, tetrabutoxytitanate and its oligomers have good compatibility with polysilane, and do not break the main chain of the polysilane, and necessarily have a hydroxyl group, an alkoxy group or a halogen as a terminal group which is inevitably generated during the production of the polysilane. By reacting with atoms to form a crosslinked structure, the mechanical properties of the thin film are improved, and cracks and breaks can be prevented. Therefore, it is the most suitable compound that can impart stable functionality to polysilane. In this case, the following can be used as tetrabutoxy titanate and its oligomer.

[0022]

Embedded image (However, ⁿ Bu represents normal butane, and n is 1 to 10
It is. )

The amount of the organic titanium compound varies depending on the type of the organic titanium compound and the type of the polysilane.
Desirably, the amount is 5 to 50 parts by weight, and if the addition is less than 1 part by weight, a sufficient effect of improving mechanical properties, particularly brittleness is not obtained, and if the addition is more than 100 parts by weight. In some cases, a negative effect such as deterioration in film forming processability and storage stability may appear rather than an improvement in mechanical properties. This is particularly remarkable when the amount of hydrolyzable groups such as alkoxy groups present in the polysilane is large, and may cause cracks or the like over time.

As the organic solvent capable of dissolving both the polysilane and the organic titanium compound, aromatic hydrocarbons such as benzene, toluene and xylene, and ether solvents such as tetrahydrofuran and dibutyl ether are preferably used. The amount of the organic solvent used is polysilane 100
It can be 100 to 100,000 parts by weight based on parts by weight.

The method of mixing and shaping the polysilane and the organotitanium compound is as follows.
It can be performed by molding while evaporating the organic solvent. In this case, as a method for forming the polysilane film, a normal polysilane thin film forming method such as a spin coating method, a dipping method, a casting method, a potting method, a dispense method, and an LB method (Langmuir-Blodgett method) can be adopted. In particular, when performing the crosslinked film of the present invention, it is preferable to perform curing. This can promote the evaporation of the solvent and the crosslinking reaction.

In particular, as a method for forming a polysilane film,
A spin coating method in which the polysilane solution is molded while rotating at a high speed is preferably used. The concentration of the solution is 0.1
Preferably, it is set to about 67% by weight. If it is less than 0.1% by weight, good film formation cannot be performed, and if it exceeds 67% by weight, storage stability may be deteriorated. Usually 1-20% by weight
Is preferably used, whereby 0.01 to 100 μm
Can be formed.

After that, drying is performed by leaving the film to stand in a dry atmosphere for a while (nekase) or leaving it to stand at a temperature of about 40 to 60 ° C. under reduced pressure (aging). It is particularly effective for further improving.

When the crosslinkable polysilane composition of the present invention is used as a functional material, the composition is usually formed into a thin film for use. This molded product has improved brittleness and solvent resistance, prevents cracks and breakage, is easy to handle, has improved light stability, and can be applied to various uses.

[0029]

The crosslinkable polysilane composition of the present invention can be easily formed into a film or coating having an arbitrary shape in a liquid state, and is a transparent molded product having improved mechanical properties and solvent resistance. Because of its excellent light stability, it is possible to obtain a molded product suitable for a functional material exposed to light. The crosslinkable polysilane composition obtained according to the present invention is a protective film for absorbing ultraviolet light, which requires light stability, an antistatic protective film, a material for solar cells, an element material for sensors, a housing for electromagnetic shielding,
It can be used as a useful material applicable to a resist or the like that can be used as a base for a multilayer film, and is widely used in the electric, electronic, and communication fields.

[0030]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Synthesis Examples, Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Synthesis Example] Synthesis Example of Polysilane Polysilane was synthesized by the following Wurtz reaction. In the Wurtz reaction, metallic sodium is first added to toluene under a nitrogen stream, and the mixture is heated to 100 to 110 ° C. and dispersed while stirring at high speed. To this, dichlorodiorganosilane is slowly added dropwise with stirring. The charge amount is 1 mol of a silicon compound per 2 to 3 mol of metallic sodium. The reaction was completed by stirring for 4 hours until the raw materials disappeared, then, after standing to cool, the salt was filtered, concentrated, and purified, whereby the polysilane could be easily obtained.

That is, the synthesis of phenylmethylethoxypolysilane was performed as follows. Under a nitrogen stream, 5.06 g (220 mmol) of metallic sodium was added to 60 m of toluene.
and heated to 110 ° C. while stirring at high speed to disperse. This is followed by phenylmethyldichlorosilane.
1 g (80 mmol), 0.8 g of trichlorosilane (5
mmol), 0.8 g of tetrachlorosilane (5 mmol
l) was slowly added dropwise with stirring. The mixture was stirred for 4 hours until the raw materials disappeared to complete the reaction. After allowing this to cool, 10
Add ethanol to the mixture, heat to 60 ° C. and stir for 4 hours, filter and concentrate the salt, 8.0 g of crude polysilane.
(Crude yield 63%) was obtained. This polymer was dissolved again in 30 ml of toluene, 120 ml of hexane was added to the solution, and the solution was separated by precipitation to obtain 5.2 g (yield: 45%) of polysilane having a weight average molecular weight of 25,000. This is referred to as polysilane A (m = polysilane A =
0.89, n = 0.89, p = 0.056).

The synthesis of phenylmethylpolysilane was performed as follows. Under a nitrogen stream, 5.06 g (220 mmol) of metallic sodium was added to 60 ml of toluene, and heated and dispersed at 110 ° C. while stirring at high speed. 19.1 g of phenylmethyldichlorosilane
(100 mmol) was slowly added dropwise with stirring. The mixture was stirred for 4 hours until the raw materials disappeared to complete the reaction. Next, after standing to cool, the salt was filtered and concentrated to obtain 10.0 g of crude polysilane (crude yield 83%). This polymer was dissolved again in 30 ml of toluene, 120 ml of hexane was added to the solution, and the solution was separated by precipitation to obtain 6.6 g (55% yield) of phenylmethylpolysilane having a weight average molecular weight of 45,000. This is designated as polysilane B (m = 1, n = 1, p = 0 of polysilane B).

Examples 1 and 2 and Comparative Examples 1 and 2 90 parts by weight of polysilane (polysilanes A and B produced in the synthesis examples) and 10 parts by weight of tetrabutoxytitanate were added to toluene 1
2,000 parts by weight, and this solution was spin-coated on a quartz glass plate at 3000 rpm for 10 seconds.
/ 50 ° C. to form a polysilane A-titanium film and a polysilane B-titanium film. For comparison, the same operation was carried out except that 100 parts by weight of polysilane and 0 parts by weight or 110 parts by weight of tetrabutoxytitanate were used to form a polysilane A film and a polysilane B film.

This film was immersed in THF for 10 seconds, and before and after the change in the film thickness and the change in the ultraviolet absorbing ability, the results were as follows.

[0036]

[Table 1]

Claims (5)

[Claims] 1. A crosslinkable polysilane composition comprising, as a main component, a polysilane, an organic titanium compound, and an organic solvent dissolving them. 2. The polysilane is represented by the following general formula (1) (R ¹ _m R ² _n X _p Si) _q (1) (wherein R ¹ and R ² are a hydrogen atom or a substituted or unsubstituted aliphatic, An alicyclic or aromatic monovalent hydrocarbon group, X is a hydroxy group, an alkoxy group or a halogen atom, and m is 0 ≦
m ≦ 2, n is 0.1 ≦ n ≦ 2, p is 0 <p ≦ 0.2
And a positive number satisfying 1 ≦ m + n + p ≦ 2.5,
q is an integer of 5 ≦ q ≦ 100,000. The crosslinkable polysilane composition according to claim 1, which is represented by the following formula: 3. The crosslinkable polysilane composition according to claim 1, wherein the organic titanium compound is an alkoxy titanate, a titanium acetylacetonate or a titanium carboxylate. 4. The crosslinkable polysilane composition according to claim 3, wherein the alkoxy titanate is tetrabutoxy titanate or an oligomer thereof. 5. A crosslinked polysilane film obtained by forming the crosslinkable polysilane composition according to claim 1, 2 or 3 into a film, and removing an organic solvent.