JPH058094B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a composite article containing a thin film formed by partially ring-closing a polyimide precursor having excellent electrical insulation properties.
A thin film formed by using an amphoteric polyimide precursor modified to be film-formable by the Blodget method (hereinafter referred to as the LB method), accumulated on a substrate by the LB method, and subsequent partial imidization reaction or ring-closing reaction. It relates to a composite article containing. Mainly used in the electronics field. Conventional technology Already in the 1930s, Langmiur and Blodget discovered that fatty acids with about 16 to 22 carbon atoms could form a monomolecular film on the water surface and accumulate it on a substrate. It has only recently begun to be carried out. For an overview of previous research, see Solid State Physics 17
(12)45 (1982) Thin Solid Films 68 No.1 (1980)
ibid, 99 No.1.2.3 (1983) Insoluble monolayers at
liquid-gas interfaces (GLGains, Interscience
Publishers, New York, (1966), etc., the conventional Langmiur-Blodget film (hereinafter referred to as "LB film") of straight chain saturated fatty acids.
has shortcomings in heat resistance and mechanical strength, and cannot be used as is for practical applications. Unsaturated fatty acids such as ω-tricosenic acid, ω-peptadenoic acid and α
- Polymer films made of octadecyl acrylic acid, unsaturated esters of fatty acids such as vinyl stearate, octadecyl acrylate, and diacetylene derivatives have been investigated, but they do not have sufficient heat resistance and do not have good electrical properties. It cannot be called a thing. Polymers with hydrophilic groups such as polyacids, polyalcohols, ethyl acrylates, and polypeptides are known to have film-forming properties, but modified polymers are particularly useful as materials for Langmiur-Blodget membranes. The molecule has not been studied so far, and there is no excellent LB membrane material, and composite articles containing it have problems with heat resistance and mechanical strength, making it difficult to put it into practical use. On the other hand, there is polyimide as a heat-resistant film, but it can be made by spin coating or other methods.
It is extremely difficult to create a heat-resistant thin film with excellent electrical insulation properties of 1000 Å or more, usually 1 μm or more and 1000 Å or less, and composite articles containing the thin film cannot be created. The present invention was made to obtain a composite article containing a LB film with improved mechanical properties such as heat resistance and adhesive strength, and chemical resistance, and includes a heat-resistant thin film with excellent electrical insulation properties. The purpose is to provide composite articles. Means for Solving the Problems The present invention was made based on the discovery that it is possible to introduce a substituent to impart hydrophobicity to a polyamic acid unit. General formula (1) proposed in patent application No. 157354, etc.: (wherein R ¹ is a tetravalent group containing at least 2 carbon atoms, R ² is a divalent group containing at least 2 carbon atoms, R ³ , R ⁴ , R ⁵ and R ⁶ are Both are monovalent aliphatic groups having 1 to 30 carbon atoms, 1
A monovalent group in which a valent cycloaliphatic group or an aromatic group is bonded to a fatty acid group, and these groups are substituted with a halogen atom, a nitro group, an amino group, a cyano group, a methoxy group, or an acetoxy group. group or a hydrogen atom, and at least one of R ³ , R ⁴ , R ⁵ and R ⁶
an amphoteric polyimide precursor having repeating units of 1 to 11 carbon atoms, preferably 2 of which are not hydrogen atoms or the above-mentioned groups having 1 to 11 carbon atoms, is deposited on the substrate by the Langmeur-Blodget method, followed by This is achieved by partially performing an imidization reaction. The amphoteric polyimide precursor for forming the polyimide thin film of the present invention has, for example, the general formula (1): The number average molecular weight with a repeating unit represented by
2000-300000. Number average molecular weight is 2000
If it is out of the range of ~300,000, there is a tendency that the strength of the film produced is too low or the viscosity is too high, making it difficult to produce the film. R ¹ in general formula (1) is a tetravalent group containing at least 2 carbon atoms, preferably 5 to 20 carbon atoms, and may be an aromatic group; It may be a group consisting of an aromatic group and an aliphatic group, and furthermore, these groups may be an aliphatic group having 1 to 30 carbon atoms, or a cycloaliphatic group having 1 to 30 carbon atoms. group, or a group in which an aromatic group and an aliphatic group are bonded together, such a group is a monovalent group such as a halogen atom, a nitro group, an amino group, a cyano group, a methoxy group, or an acetoxy group; The group is -O-, -COO-, -NHCO-, -CO
It may be a group substituted with a group bonded to -, -S-, -CSS-, -NHCS-, -CS-, etc. to form a derivative. However, it is preferable from the viewpoint of heat resistance, chemical resistance, mechanical properties, etc. when R ¹ is a group characterized by benzenoid unsaturation having at least 6 carbon atoms. As a specific example of R ¹ as mentioned above, for example,

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】 【formula】

[Formula] etc. The term "benzenoid unsaturation" as used herein is a term used in contrast to a quinoid structure regarding the structure of a carbocyclic compound, and refers to a structure having the same shape as a carbocyclic ring contained in ordinary aromatic compounds. In the four bonds of R ¹ , that is, the repeating unit represented by general formula (1)

【formula】

【formula】

【formula】

There is no particular limitation on the position of the bonding hands in [Formula], but two of each of the four bonding hands are adjacent to two that make up R ¹ .
When carbon atoms exist, it is preferable because it facilitates the formation of a five-membered ring when polyimidizing a film formed using an amphoteric polyimide precursor. Preferred specific examples of the above-mentioned R ¹ include, for example. Also

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】 Examples include. Also

[Formula] is also preferred. R ² in general formula (1) is a divalent group containing at least two carbon atoms, and may be an aromatic group, an aliphatic group, or a cycloaliphatic group. It may be a group in which an aromatic group and an aliphatic group are combined, and furthermore, these divalent groups may be an aliphatic group having 1 to 30 carbon atoms, a cycloaliphatic group, or a group in which an aromatic group and an aliphatic group are bonded. group, or a group in which an aromatic group and an aliphatic group are bonded, and these groups are monovalent groups such as a halogen atom, a nitro group, an amino group, a cyano group, a methoxy group, and an acetoxy group; The monovalent group is -O-, -COO-, -NHCO-, -CO-,
It may be a group substituted with a group bonded to -S-, -CSS-, -NHCS-, -CS-, etc. but,
When R ² is a group characterized by bensenoid unsaturation having at least 6 carbon atoms, it is preferred from the viewpoint of heat resistance, chemical resistance, mechanical properties, etc. As a specific example of the above-mentioned Goki R ² ,

【formula】

【formula】

【formula】

[Formula] Here, R ⁹ is -(CH ₂ )m- (m = integer from 1 to 3),

【formula】

[Formula] -O-, -CO-, -S-, -SO ₂ -,

【formula】 【formula】

【formula】

【formula】

[Formula] R ¹⁰ and R ¹¹ are both alkyl or aryl groups having 1 to 30 carbon atoms

【formula】

[Formula] −(CH ₂ ) _p ( _p = 2 to 10),

【formula】

【formula】

【formula】

【formula】

[Formula] −(CH ₂ ) ₃ −O−(CH ₂ ) ₂ −O−(CH ₂ ) ₃ −,

【formula】

【formula】

etc., and preferred specific examples of R ² as described above include, for example:

【formula】

【formula】

【formula】

[Formula] (In the formula, R ⁹ is -(CH ₂ ) _n (m = integer from 1 to 3),

【formula】

[Formula] -O-, -CO-, -S-, -SO ₂ -, -NR ¹⁰ -,

【formula】

【formula】

【formula】

[Formula] (R ¹⁰ and R ¹¹ are both alkyl or aryl groups having 1 to 30 carbon atoms). In general formula (1), R ³ , R ⁴ , R ⁵ , and R ⁶ all have 1 to 30 carbon atoms, preferably 1 to 22 carbon atoms.
a valent aliphatic group, a monovalent cycloaliphatic group, a monovalent group combining an aromatic group and an aliphatic group, these groups are halogen atoms, nitro groups, amino groups, cyano groups, A hydrogen atom or a group substituted with a methoxy group, an acetoxy group, etc. to become a derivative of those groups. In general formula (1), R ³ , R ⁴ , R ⁵ and
All R ⁶ are general formula (8): (In the formula, R ¹ , R ² are the same as above) This is a group introduced in order to impart hydrophobicity to the polyamic acid unit and obtain a stable condensed film, and R ³ , R ⁴ ,
A stable condensation film is formed on the water surface when at least one, preferably two of R ⁵ and R ⁶ are not the above-mentioned groups having 1 to 11 carbon atoms, preferably 1 to 15 carbon atoms, or hydrogen atoms. It is necessary for it to be accumulated on the substrate by the LB method. Specific examples of R ³ , R ⁴ , R ⁵ , and R ⁶ other than hydrogen atoms include, for example, CH ₃ (CH ₂ ) _o-1 ---, (CH ₃ ) ₂ CH (CH ₂ ) _{o- 3} ---
, (CH ₃ ) ₃ C(CH ₂ ) _o-4 ---,

【formula】

【formula】

[Formula] (The above n is 12 to 30, preferably 16 to
22) etc. However, in order to achieve the purpose of the present invention, it is most desirable to use a straight chain alkyl group represented by CH ₃ (CH ₂ ) _o-1 -- in terms of performance and cost. Halogen atoms as mentioned above,
Nitro groups, amino groups, cyano groups, methoxy groups, acetoxy groups, etc. are not essential. However, since fluorine atoms dramatically improve hydrophobicity compared to hydrogen atoms, it is preferable to use those containing fluorine atoms. Specific examples of the repeating unit of the amphoteric polyimide precursor of the present invention in which two of R ³ , R ⁴ , R ⁵ , and R ⁶ are hydrogen atoms include general formula (2): (In the formula, R ¹ , R ² , R ³ , and R ⁴ are the same as above, but
R ³ and R ⁴ are groups having 1 to 11 carbon atoms or are not hydrogen atoms), or the general formula
(3)： (In the formula, R ¹ , R ² , R ⁵ , R ⁵ are the same as above, but
R ⁵ and R ⁶ are groups having 1 to 11 carbon atoms or are not hydrogen atoms), and the like. When the repeating unit of the amphoteric polyimide precursor of the present invention is represented by general formula (2) or general formula (3), it is easy to manufacture and inexpensive. preferable. Specific examples of the amphoteric polyimide precursor of the present invention having repeating units represented by general formulas (1) to (3) include:
for example (Specific examples of R ³ and R ⁴ in the formula include CH ₃ (CH ₂ ) ₁₁ −, CH ₃ (CH ₂ ) ₁₃ −, CH ₃ (CH ₂ ) ₁₅
−, CH ₃ (CH ₂ ) ₁₇ −, CH ₃ (CH ₂ ) ₁₉ −, CH ₃
(CH ₂ ) ₂₁ −, CF ₃ (CH ₂ ) ₁₅ −, etc.), (Specific examples of R ⁵ and R ⁶ in the formula are CH ₃ (CH ₂ ) ₁₁ −, CH ₃ (CH ₂ ) ₁₃ −, CH ₃ (CH ₂ ) ₁₅
−, CH ₃ (CH ₂ ) ₁₇ −, CH ₃ (CH ₂ ) ₁₉ −, CH ₃
(CH ₂ ) ₂₁ −, CF ₃ (CH ₂ ) ₁₅ −, etc.), (Specific examples of R ³ and R ⁴ in the formula include CH ₃ (CH ₂ ) ₁₁ −, CH ₃ (CH ₂ ) ₁₃ −, CH ₃ (CH ₂ ) ₁₅
−, CH ₃ (CH ₂ ) ₁₇ −, CH ₃ (CH ₂ ) ₁₉ −, CH ₃
(CH ₂ ) ₂₁ −, CF ₃ (CH ₂ ) ₁₅ −, etc.), R ⁵ and R ⁶ include CH ₃ −, CH ₃ (CH ₂ ) ₂ −, CH ₃
(CH ₂ ) ₃ −, CH ₃ (CH ₂ ) ₅ −, etc.), (Specific examples of R ³ and R ⁴ in the formula include CH ₃ (CH ₂ ) ₁₁ −, CH ₃ (CH ₂ ) ₁₃ −, CH ₃ (CH ₂ ) ₁₅
−, CH ₃ (CH ₂ ) ₁₇ −, CH ₃ (CH ₂ ) ₁₉ −, CH ₃
Examples include those containing repeating units such as (CH ₂ ) ₂₁ −, CF ₃ (CH ₂ ) ₁₅ −, etc.). In the formula, → represents isomerism. For example, If you explain it with and represents. The present invention includes cases where (a) and (b) are used alone and cases where (a) and (b) coexist. The amphoteric polyimide precursor of the present invention as described above generally includes N,N-dimethylacetamide, N,
Easily soluble in organic polar solvents such as N-dimethylformamide, N,N-diethylformamide, hexamethylphosphoramide, etc., soluble in mixed solvents such as the above organic polar solvents and ordinary organic solvents such as chloroform, ordinary organic solvents, For example, it is sparingly soluble to insoluble in benzel, ether, chloroform, acetone, methanol, etc., and characteristic absorptions of amides, carboxylic acids (carboxylic acid esters in some cases), and long-chain alkyl groups are present in infrared absorption spectroscopy. . The thermal analysis results also have some characteristics, with a rapid weight loss starting at about 200°C and ending at about 400°C. After completion, the absorption of amide, carboxylic acid (carboxylic acid ester in some cases) and long-chain alkyl group disappears, and absorption of imide ring appears. The explanation so far has been about an amphoteric polyimide precursor having a repeating unit represented by the general formula (1), but as can be easily inferred from these, various copolymers exist. First of all, in general formula (1)
This is realized by at least one of R ¹ , R ² , R ³ , R ⁴ , R ⁵ , and R ⁶ consisting of at least two selected from the specific examples listed above. For example, when 2 types are selected as R ¹ x, y represent the ratio, 0<x<1, 0<y<
1, x+y=1. (The same applies hereafter) Furthermore, when the second type is selected as R ² The above example is just one example, and R ³ ,
Regarding R ⁴ , R ⁵ , and R ⁶ , many examples can be written in the explanations so far. etc. A second and more important copolymer is realized by replacing a portion of at least one or both of R ¹ and R ² with a group having a different valence. First, the group substituting a part of R ¹ is selected from non-tetravalent groups containing at least 2 carbon atoms,
A divalent or trivalent compound can be used, but a preferred specific example is a trivalent compound, and the general formula in this case is as follows. R ¹ (within [ ]x), R ² , R ³ , R ⁴ , R ⁵ , and R ⁶ are the same as above. R ¹ (in [ ]y) is a divalent or trivalent group containing at least two carbon atoms, respectively. Next, the group substituting a part of R ² is selected from groups other than divalent groups containing at least 2 carbon atoms.
4 groups are preferred. The general formula in these cases is as follows. R ¹ , R ² (within [ ]x), R ³ , R ⁴ , R ⁵ , and R ⁶ are the same as above. R ² (in [ ]y) is a trivalent or tetravalent group containing at least two carbon atoms, respectively. x is a substituent for R ² , -NHR, -
A preferred example is CONHR (R is an alkyl group or a hydrogen atom). Modification of the amphoteric polyimide precursor by these copolymerizations is important for improving the cumulative properties of the precursor by the Langmiur-Blodget method and for improving the physical properties of the polyimide thin film obtained by imidization after being accumulated on a substrate. is one of the preferred embodiments. Specific examples of the group substituting a part of at least one or both of R ¹ and R ² are as follows.

【formula】

【formula】

【formula】

[Formula] (Here, R ⁹ is the same as above) −SO ₂ −,

【formula】

【formula】

【formula】

【formula】

[Formula] R ¹⁰ and R ¹¹ are alkyl or aryl groups

【formula】

[Formula] −(CH ₂ ) _p − (p=2 to 10),

【formula】

【formula】

【formula】

【formula】

[Formula] −(CH ₂ ) ₃ −O−(CH ₂ ) ₂ −O−(CH ₂ ) ₃ −,

【formula】

【formula】

【formula】

【formula】

【formula】

[Formula] (R ⁹ is the same as above)

【formula】

【formula】

【formula】

[Formula] (R ⁹ is the same as above)

【formula】

【formula】

[Formula] From the above, a more preferable example of R ¹ and R ² is

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

[Formula] (R ⁹ is the same as above). To explain the copolymer in more detail, here are some specific examples: etc. In addition, in the explanations so far, in the precursor repeating unit, at least two of R ³ , R ⁴ , R ⁵ , and R ⁶ are not the above-mentioned groups having 1 to 11 carbon atoms or hydrogen atoms. but 30 of the repeating units
If it is within the range of %, general formula (9) (In the formula, R ¹ and R ² are the same as above, R is a monovalent aliphatic group having 1 to 11 carbon atoms, a monovalent cycloaliphatic group, an aromatic group and an aliphatic group) A bonded monovalent group, a group in which these groups are substituted with a halogen atom, a nitro group, an amino group, a cyano group, a methoxy group, an acetoxy group, etc., or a hydrogen atom, and four R
may be the same or different). Next, a method for producing the precursor of the present invention will be explained. The precursor of the present invention having a repeating unit represented by general formula (1) is first prepared by general formula (4): (wherein R ¹ is the same as above), R ³ OH and R ⁴ OH (R ³
and R ⁴ are the same as above): General formula (5) obtained by reacting: (wherein R ¹ , R ³ , and R ⁴ are the same as above) is prepared, and in a substantially anhydrous polar solvent, -
It is converted into an acid halide using thionyl chloride, phosphorus pentachloride, benzenesulfonyl chloride, etc. at 10°C or higher, preferably about 1 to 40°C, and then converted into an acid halide using the general formula (6): R ⁵ -NH-R ² -NH-R ⁶ ( 6) When adding the compound represented by (in the formula, R ² , R ⁵ , R ⁶ are the same as above), the reaction is carried out at -10 to +20°C, preferably 0 to +10°C, but the reaction is not completed. In order to achieve this, the reaction may be carried out at 20°C or higher after addition. Specific examples of compounds represented by general formula (4) include:
for example

【formula】

【formula】

[Formula] etc. In addition, specific examples of R ³ OH and R ⁴ OH include:
For example _CH3OH , _{CH3CH2OH , CH3}
( _CH2 ) _2OH , _CH3 ( _CH2 ) _3OH , _CH3 ( _CH2 ) _5OH ,
_CH3 ( _CH2 ) ₇ OH, _CH3 ( _CH2 ) ₉ OH, _CH3
( _CH2 ) ₁₁ OH, _CH3 ( _CH2 ) ₁₃ OH, _CH3
( _CH2 ) ₁₅ OH, _CH3 ( _CH2 ) ₁₇ OH, _CH3
( _CH2 ) ₁₉ OH, _CH3 ( _CH2 ) ₂₁ OH, _CH3
(CH ₂ ) ₂₃ OH, CF ₃ (CH ₂ ) ₁₅ OH, H(CF ₂ ) ₂
(CH ₂ ) ₁₅ OH, H(CF ₂ ) ₄ (CH ₂ ) ₁₃ OH, F(CF ₂ ) ₈
(CH ₂ ) ₂ OH, F(CF ₂ ) ₈ (CH ₂ ) ₄ OH,

[Formula] (CH ₃ ) ₃ C (CH ₂ ) ₁₄ OH,

【formula】

【formula】

[Formula] etc. There are no particular limitations on the reaction conditions when producing the compound represented by general formula (5) from the tetracarboxylic dianhydride represented by general formula (4), R ³ OH and R ⁴ OH, For example, it can be obtained by continuing stirring for several hours at about 100°C under a nitrogen atmosphere, or by continuing stirring at room temperature for about 4 days in a solvent such as hexamethylene phosphoramide. Adopted. The reaction time can be shortened by heating the above reaction at about 100°C for 3 hours while stirring under a nitrogen stream, and after cooling, dissolving it in hexamethylene phosphoramide, followed by acid halide formation. That is, it is preferable from the viewpoint of improving productivity. Specific examples of polar solvents used in the acid halide conversion include hexamethylene phosphoramide, N,N-dimethylacetamide, N,N-dimethylformamide, and the like. In other words, thiocnyl chloride, phosphorus pentachloride, benzenesulfonyl chloride, etc. used in the acid halide conversion are not decomposed, and the acid halide reaction is carried out in a nearly quantitative manner. If the temperature during acid halide conversion is less than -10°C, the reaction becomes heterogeneous due to freezing and solidification due to the effect of long-chain alkyl groups, which is undesirable. It can be used without particular limitation up to the temperature. The acid halide thus produced is further reacted with a compound represented by general formula (6) to produce the precursor of the present invention. The acid halide used in this case is preferably used as it is after being produced in terms of workability and the like. Furthermore, when ^the acid halide is reacted with the compound represented by the general formula ( ^{6 )} , both ^the reactant and the product are N,N-dimethylacetamide, N,N
-It is common to use a solvent such as dimethylformamide, and the reaction temperature is -10℃ to +20℃.
℃, preferably 0 to -10℃. The reaction temperature is -
If the temperature is lower than 10°C, the reaction becomes heterogeneous due to freezing and solidification, and if the temperature exceeds +20°C, undesirable reactions are likely to occur, both of which are unfavorable. Of course, in order to complete the reaction, the reaction may be continued at a temperature of 20° C. or higher after the addition. Specific examples of the compound represented by the general formula (6) include, for example: (Specific examples of R ₅ and R ₆ in the formula include CH ₃ −, CH ₃ CH ₂ −, CH ₃ (CH ₂ ) ₂ −, CH ₃
(CH ₂ ) ₃ −, CH ₃ (CH ₂ ) ₅ −, CH ₃ (CH ₂ ) ₁₁ −,
CH ₃ (CH ₂ ) ₁₃ −, CH ₃ (CH ₂ ) ₁₅ −, CH ₃ (CH ₂ ) ₁₇
−, CH ₃ (CH ₂ ) ₁₉ −, CH ₃ (CH ₂ ) ₂₁ −, CH ₃
(CH ₂ ) ₂₃ −, CF ₃ (CH ₂ ) ₁₅ −, H(CF ₂ ) ₂ (CH ₂ ) ₁₅
−, H(CF ₂ ) ₄ (CH ₂ ) ₁₃ −, F(CF ₂ ) ₈ (CH ₂ ) ₂ −,
F(CF ₂ ) ₈ (CH ₂ ) ₄ −, etc.). The reaction ratio between the acid halide and the compound represented by general formula (6) may be appropriately selected in order to obtain a desired molecular weight of the precursor of the present invention, but usually the molar ratio is 1. /0.8 to 1.2. In order to obtain high molecular weight products, it is preferable to use purified monomers and purified solvents in stoichiometry. R 3 and ^{R 4 of} R ³ OH and R ⁴ OH reacted with tetracarboxylic diacid anhydride represented by general formula (4)
is not a group having 1 to 11 carbon atoms or a hydrogen atom, the compound represented by general formula (6)
Both R ⁵ and R ⁶ may be hydrogen atoms,
In this case, a precursor of the present invention having a repeating unit represented by general formula (2) can be obtained. When R ⁵ and R ⁶ of the compound represented by general formula (6) are both hydrogen atoms, the reactivity is good and the raw material cost is low, which is preferable. In addition, the resulting precursor is thermally stable because the carboxylic acid is an ester, and the reaction does not proceed through isolation and drying, so it can be separated as a solid powder, which also makes it easy to purify. Become what you have. The precursor of the present invention is produced by the method explained above, but when R ³ and R ⁴ of the repeating unit represented by general formula (1) are both hydrogen atoms,
The general formula (7): R ⁷ −NH−R ² −NH−R ⁸ (7) (formula The precursor of the present invention having a repeating unit represented by the general formula (3) can be obtained by reacting a compound represented by R 7 and R ⁸ (in which R ⁷ and R 8 are the same as above). Specific examples of the compound represented by the general formula (7) include, for example: (In the formula, specific examples of R ⁷ and R ⁸ include CH ₃ (CH ₂ ) _o-1 ( _o = 12 to 30), CF ₃ (CH ₂ ) ₁₅ −,
H(CF ₂ ) ₂ (CH ₂ ) ₁₅ −, H(CF ₂ ) ₄ (CH ₂ ) ₁₃ −, H
(CF ₂ ) ₈ (CH ₂ ) ₂ −, H(CF ₂ ) ₈ (CH ₂ ) ₄ −, etc.). The conditions for reacting the tetracarboxylic acid dianhydride represented by general formula (4) with the compound represented by general formula (7) are almost the same as those for producing ordinary polyamic acid. Often, in a substantially anhydrous organic polar solvent such as N,N-dimethylacetamide, N,N-dimethylformamide, etc., at a reaction temperature of 50°C.
0.8 to 1.2 mol of the compound represented by the general formula (7) can be reacted with 1 mol of the tetracarboxylic diacid anhydride represented by the general formula (4) at a temperature below .degree. C., preferably at room temperature. The precursor of the present invention having a repeating unit represented by the general formula (3) obtained in this way is not only easy to manufacture, but also has the characteristics of being able to be formed into a film by the LB method and forming polyimide by heating. It is something that you have. Further, the copolymer described above can be produced by a method similar to that of the amphoteric polyimide precursor. The amphoteric polyimide precursor produced as described above may be separated and purified to be used as a film-forming material, or if necessary after production, chloroform, benzene, etc. may be added to it and used directly as a film-forming solution. A method for forming the polyimide precursor thin film of the present invention will be described. There are solvent casting methods, spin coating methods, and Langmeur-Blodget methods, and the Langmeur-Blodget method is used for orientation. This method is preferable as a method for obtaining a thin film with a controlled thickness of several angstroms and few pinholes. In the case of the solvent casting method and the spin coating method, the polyimide precursor of the present invention or a mixture thereof is dissolved in a solvent such as benzene, chloroform, ethyl ether, ethyl acetate, tetrahydrofuran, dimethylformamide, N,N-dimethylacetamide, etc. It can be applied by coating it on top of the film, and it is not possible to orient the molecules, but if the film thickness is
When the thickness is greater than about 1000 Å, a high quality film without pinholes can be obtained. Next, a method will be described in which the precursors described above are accumulated on a substrate by the Langmiur-Blodget method, followed by an imidization reaction. The method for producing an LB film using the precursor of the present invention is as follows:
In addition to the LB method, which is a method in which the precursor is spread on the water surface and compressed with a constant surface pressure to form a monomolecular film, and the film is transferred onto a substrate, there are other methods such as the horizontal deposition method and the rotating cylinder method. (New Experimental Chemistry Course Vol. 13, Interfaces and Colloids, pp. 498-508), etc., and any commonly used method may be used without particular limitation. Generally, when a substance for forming an LB film is spread on a water surface, solvents such as benzene and chloroform are used, which do not dissolve in water and evaporate into the gas phase, but in the case of the precursor of the present invention, solvents such as benzene and chloroform are used. It is desirable to use an organic polar solvent in combination to increase solubility. Examples of such organic polar solvents include N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylformamide, N,N-diethylacetamide, N,N-dimethylmethoxyacetamide, dimethylsulfoxide, -Methyl-2-pyrrolidone, pyridine,
Examples include dimethylsulfone, hexamethylphosphoramide, tetramethylenesulfone, dimethyltetramethylenesulfone, and the like. When benzene, chloroform, etc. are used together with an organic polar solvent, it is thought that when developed on the water surface, the benzene, chloroform, etc. will evaporate into the gas phase, and the organic polar solvent will dissolve in a large amount of water. There is no particular limitation on the concentration of the solution used when spreading the precursor of the present invention on the water surface, but it is usually 2 to 5.
×10 ^-3 M is used, and addition of metal ions and pH adjustment are not necessarily necessary to obtain good film-forming properties, and the exclusion of metal ions is considered to be an advantage when used in the electronics field. It will be done. Additionally, when the polyimide precursor of the present invention is deposited on a substrate, the use of a mixture with known Langmiur-Blodget film compounds as we previously proposed improves the film forming performance, and the preferred implementation of the present invention. It is a mode. The known Langmiur-Prodget film compound is a compound that is described in the literature cited above and is known in the art. Especially carbon number 16 to 22
A compound of the following formula consisting of a hydrocarbon group and a hydrophilic group is preferred. CH ₃ (CH ₂ ) _o-1 Z CH ₂ = CH (CH ₂ ) _o-2 Z CH ₃ (CH ₂ )lC=C-C=C(CH ₂ ) _n Z where n=16 to 22, l+m=n-5, Z=
These include OH, NH ₂ , COOH, CONH ₂ , COOR'(R' is a lower aliphatic hydrocarbon group), and the like. To improve film formability, the formula represented by CH ₃ (CH ₂ ) _o-1 Z is superior in terms of cost, but those containing unsaturated bonds require irradiation with light or radiation. It has the characteristic that it can be polymerized by. There is no particular limitation on the mixing ratio of at least one compound selected from these and the polymer compound. It is also possible to form a film by mixing two or more selected from the polyimide precursors or copolymers listed above. The substrate on which the LB film using the precursor of the present invention is formed is not particularly limited, and may be selected depending on the purpose of the formed LB film, but when the LB film is heated and used as a polyimide, It is necessary to have good heat resistance. Specific examples of the above-mentioned substrates include glass,
In addition to inorganic substrates such as alumina, quartz, etc.
Plastic substrates, inorganic substrates, metal thin films formed on plastic substrates, metal substrates, and groups such as Si, GaAs, and ZnS,
− group, − group semiconductors, PbTiO ₃ ,
Examples include ferroelectric substrates or magnetic substrates such as BaTiO ₃ , LiNbO ₃ , and LiTaO ₃ . Of course, the metal thin film on the substrate as described above may be patterned as appropriate for the application,
A substrate made of a semiconductor such as Si, GaAs, or ZnS or a ferroelectric material may be processed in advance to form an element. Furthermore, it goes without saying that these substrates may be used after being subjected to a commonly used surface treatment. In the case of the polyimide precursor of the present invention, adhesive strength tends to be weak on surfaces such as glass, quartz, Si, and SiO ₂ , and silane coupling agents, especially silane coupling agents having amino groups, epoxy groups, and alkoxy groups, are recommended. Ring agent (e.g. UCC A-1100 or A
-187, etc.) or a chelate containing aluminum metal to form an aluminum oxide layer improves film forming properties and adhesive strength, and is a preferred embodiment of the present invention. Of course, the substrate may be treated with several layers of higher fatty acid metals as is done in the art. By using the precursor of the present invention, a thin film with good heat resistance, mechanical properties, chemical resistance, and electrical insulation properties can be formed on a substrate by the LB method, and further, by imidizing this thin film, Furthermore, a thin film with excellent heat resistance can be obtained. There are no particular limitations on the imidization method, but
Heating is generally performed at a temperature around 300 to 400°C, and may be performed using laser light or the like. Of course, acetic anhydride and pyridine used in imidization of polyamic acid may be used, or they may be used in combination with a thermal reaction. For example, general formula (2)
For the repeating unit represented by In the case of the repeating unit represented by the general formula (3), A reaction occurs to form a polyimide. Of course, in the case of the polyamic acid unit represented by the general formula (8), H ₂ O is generated and a polyimide is formed, but
In this case, it cannot be used as a material for LB film. Furthermore, when at least one or both of R ¹ and R ² is partially replaced with a group having a different valence, the following reaction occurs under the same conditions as the imidization reaction. In particular, the latter two examples introduce a skeleton with high heat resistance, which is preferable for improving heat resistance. When the above imidization and ring-closing reactions occur, the groups introduced for hydrophobization are eliminated as alcohol, but this eliminated alcohol is heated at a temperature around 300° to 400° under a gas flow if necessary. Since the polyimide film can be dispersed by placing it in a vacuum or by placing it in a vacuum, it is possible to obtain a polyimide thin film that is extremely heat resistant and has good electrical insulation properties. In addition, the known Langmiur-Blodget film compounds used to improve film-forming properties can be modified by adjusting the conditions for imidization and ring-closing reactions, and by selecting compounds that can be dispersed from the examples listed above. As a result, a polyimide thin film that is extremely heat resistant and has good electrical insulation properties can be obtained. Further intensive studies have revealed that it is possible to accumulate an amphoteric polyimide precursor on a substrate using the Langmiur-Blodget method, and then imidize it under milder conditions than to completely imidize it (ring closure). The partially ring-closed polyimide thin film produced by ring-closing (ring-closing) has heat resistance of over 200℃ and excellent chemical resistance.
It has good mechanical properties, excellent electrical insulation, and is an extremely thin film of less than 10,000 Å, and can be made as thin as 5,000 Å, 2,000 Å, and even 10 to 1,000 Å if desired. The term "partial imidization (ring closure)" in the present invention includes an imidization rate of more than 0% and less than 100%, but from the perspective of heat resistance, it conversion rate of approximately 40% or more
Preferably it is less than 100%. As shown in the reference example, it is clear from the area-time curve that the amphoteric polyimide precursor becomes an ideal Y-shaped film even by the Langmiur-Blodget method (vertical method), but the I/C (reciprocal of capacitance) vs. The linearity of the film number plot and the X-ray diffraction data suggest that the amphoteric polyimide precursor cumulative film has a layered structure expected for LB films. It is also clear that the thin film of this precursor has excellent film thickness controllability, as well as good heat resistance, dielectric properties, and electrical insulation properties. Next, a polyimide thin film made by partially imidizing (ring-closing) this precursor thin film will be described. It is clear from the Examples that this polyimide thin film has excellent heat resistance. It has excellent film thickness controllability even after imidization, and the film thickness of the partially closed polyimide thin film can be controlled by the cumulative number of films of the amphoteric polyimide precursor, and the existence of a layered structure is presumed. It has been revealed that this partially ring-closed polyimide thin film has good dielectric properties and electrical insulation properties. The partially ring-closed polyimide thin film has particularly excellent electrical insulation and dielectric properties because long-chain alkyl groups remain. In particular, it has been revealed that, according to the present invention, even a partially ring-closed polyimide thin film of 1000 Å or less can have a dielectric breakdown strength of 1×10 ⁶ V/cm or more. By this method, it is possible to realize a film with good physical properties of about 10,000 Å, but considering the cost of forming an LB film, a thin film is cheaper, and in terms of application, it is possible to create a thin film that cannot be made using other methods. I'm interested in membranes. i.e. less than 2000Å or even 1000Å
There are new and interesting applications for films with a thickness of Å or less, several hundred Å, or 50 to 100 Å, but it is difficult to achieve a dielectric breakdown strength of 1 × 10 ⁶ V/cm or more with such a film thickness. was difficult. However, it has become clear that according to the method of the present invention, a polyimide thin film having a dielectric breakdown strength of 1×10 ⁶ V/cm or more, which is sufficiently usable in the electronics field, can be realized.
In particular, for thin films from about 50 Å to several hundred Å, unique film thickness effects, such as tunneling effects, are expected.
Many interesting applications using it become possible. Spin coating is a method for creating such a thin partially ring-closed polyimide film with long-chain alkyl groups, but it achieves a dielectric breakdown strength of 1×10 ⁶ V/cm or more even at a thickness of 1 μm or more. It should be understood that it is difficult to create a polyimide thin film with a dielectric breakdown strength of 1×10 ⁶ V/cm or more with a thickness of 1 μm or less using current technology. . In addition, a partially ring-closed polyimide thin film is imidized under milder conditions than complete imidization, so it is preferably used in cases where the heat resistance of the substrate or element is not very good. can. As mentioned above, an amphoteric polyimide precursor having a repeating unit represented by the general formula (1) is accumulated on a substrate by the Langmiur-Blodget method, and a substrate made by a subsequent partial imidization reaction is formed. Polyimide thin film has good heat resistance, mechanical properties, and chemical resistance, and has excellent electrical insulation properties.Moreover, it is an extremely thin film of less than 10,000 Å, and can be made as thin as 5,000 Å, 2,000 Å, or even 10 to 1,000 Å if desired. It has In particular, it is possible to achieve a dielectric breakdown strength of 1×10 ⁶ V/cm or more with good physical properties even at a thickness of 1000 Å or less, several hundred Å, or 50 to 100 Å, so it can be used in composite articles such as various electrical and electronic devices. can. In particular, in thin films from about 50 Å to several hundred Å, unique film thickness effects such as tunneling effects are expected, and many interesting electrical and electronic devices using this effect will become possible. Next, the composite article of the present invention will be described. The thin films described above have excellent heat resistance, chemical resistance, and mechanical properties, and can be used in a wide range of fields such as electronics, energy conversion, and material separation by taking advantage of the characteristics that they are extremely thin films. First, we will discuss electrical and electronic devices, which are composite articles in the electronics field that take advantage of conductivity, photoconductivity, optical properties, insulation, thermal properties, and chemical reactivity. Firstly, electrical and electronic devices containing the thin film of the present invention are metal/insulating film/semiconductor structures (hereinafter referred to as MIS).
) and is the basic structure of planar electronic devices and integrated circuits. 1 to 7 are representative schematic diagrams. In FIG. 1, a thin film of the present invention is formed as an insulating film on a semiconductor substrate, and a metal electrode is provided thereon. Si, Ge
By using - group semiconductors such as GaAs and GaP, and - group semiconductors such as CdTe, CdS, ZnS, ZnSe, and CdHgTe, photoelectric conversion elements such as solar cells LED, EL, and photodiodes can be manufactured. In addition to light emitting elements, light receiving elements, and light detecting elements, various transducers such as gas sensors and temperature sensors can be constructed. Of course, the semiconductor of the present invention may be selected from single crystal, polycrystal, or amorphous. Although FIG. 2 is similar to FIG. 1, such electrodes are attached when two or more elements are to be formed on one substrate. With this configuration, CCD (Charge-
Charge-transfer devices such as coupled devices have been created and are an interesting application. Next, Figure 3 shows an electrode (which may be a transparent electrode).
In many cases, a semiconductor thin film is formed on an insulating substrate having a pattern (of course, it may be patterned), and the thin film electrode of the present invention is provided thereon. FIG. 4 differs from FIG. 3 in that the thin film is provided between the insulating substrate side electrode and the semiconductor thin film. Semiconductor thin films are typically manufactured using methods such as molecular beam epitaxy (MBE), metal organic chemical vapor deposition (MOCVD), atomic layer epitaxy (ALE), vapor deposition, sputtering, spray pyrolysis, and coating methods. It is made in a method that is used and is not limited. As semiconductors, those listed above in FIGS. 1 and 2 can be used in the same way, and the devices produced are also the same. In the configuration shown in Figure 4, a semiconductor thin film is formed on the thin film of the present invention, so it is not desirable if the heat during formation exceeds the heat resistance of the thin film, but amorphous silicon etc. is sufficient for a film with a fairly high imidization rate. It can be accumulated, and low-temperature formation technology for other semiconductors is progressing, so many semiconductors will be able to be used in the future. The most important device structure of MIS structure devices is the so-called field effect transistor (FET) structure, which is typically driven by controlling the channel current with a gate electrode, as shown in FIGS. The difference is that FIG. 5 uses a semiconductor substrate, whereas FIG. 6 uses a semiconductor thin film formed on an insulating substrate in most cases. MISFET is one of the basic types of devices,
This allows various devices to be made.
If made on a large-area substrate, thin-film transistors can be used to drive a liquid crystal display, and if the degree of integration is increased, an integrated circuit can be constructed. Another interesting application is the structure in which the gate electrode is removed as shown in Figures 5 and 6, and an ion-sensitive FET (ISFET) or gas sensitive EET (ChemFET), immune FET (IMFET),
Enzyme FET (ENFET) can be configured. The operating principle can be explained by the electric field effect caused by the interaction of ions or gas active substances with the surface of the gate insulating film, but when using a thin film like the one of the present invention, it is difficult to further modify it with various organic substances. has advantages over conventional organic materials. In particular, in thin films with long-chain alkyl groups remaining, the interaction between the alkyl group (hydrophobic) portion and the hydrophobic portion of the protein can be utilized. FIG. 7 shows an example of an ISFET, which has a structure in which a semiconductor film is formed on a quartz substrate as shown in the figure, and an insulating film and an ion-sensitive film are provided thereon. The thin film of the present invention can be used as this insulating film. A preferred embodiment of the present invention is to use compound semiconductors such as - and - group semiconductors, in which it is difficult to form good insulating films by methods such as oxidation, as semiconductors when configuring devices with MIS structures. In this case, when forming an FET, Metal-Semiconductor FET is used due to the above problems.
Although it has been put into practical use in the form of (MESFET), it is expected that performance will improve by adopting an MIS structure. Constructing MIS integrated circuits using GaAs not only has the effect of lowering the driving voltage, but also allows for the creation of high-speed integrated circuits (HEMTs) that take advantage of the large carrier mobility in GaAs semiconductors. You can make it. The second important electric/electronic device containing the thin film of the present invention is a device with a metal/insulating film/metal (hereinafter referred to as MIN) structure. 8 to 10 are schematic diagrams. An insulating or semiconductor substrate is used, and metal, insulating films,
Formed in the order of metals. Figure 8 shows the structure of a capacitor, which can be used as a humidity sensor by tracking changes in capacitance due to humidity. Also, with this structure, it is also possible to create a transistor with an MIM structure. A thermionic transistor can be constructed as shown in FIG. By making a capacitor on a semiconductor or semiconductor device as shown in FIG. 10, it can be used as a capacitor for a VLSI memory cell. With the configuration shown in FIG. 10, it is also possible to create a type of device in which hot electrons are injected into a semiconductor. It is also possible to create JJ devices by using electromotive conductors such as Nb instead of metals. The electrical/electronic device including the third thin film is a device with an insulating film/metal structure (IM structure), and is schematically represented in FIG. 11. It is at least simple and can be obtained by forming the thin film of the present invention as an insulating film on a metal. One application is in liquid crystal alignment films, which are obtained by forming the thin film of the invention on a patterned electrode, usually a transparent electrode such as ITO. In the next application, by forming the thin film of the present invention on two independent electrodes in FIGS. 12 and 13, it can be used as a sensor for humidity, gas, etc. The electrical and electronic devices containing the thin film of the present invention have been described above, but other application examples can be found in the above-mentioned literature, especially in the review by PSVincett and GG Roberts (Thin Solid Flims 68 135-137 (1980)). For other semiconductor devices and compound semiconductor devices, please refer to ESyang, Fundamentals of
Semiconductor Devices MaGraw-Hill, 1978
Edited by Imai et al., Compound Semiconductor Devices [] []
You can refer to the book written by Kogyo Kenkyukai (1984). Next, we will discuss composite articles other than electrical/electronic devices. Recording methods are increasingly being adopted in which bit formation or phase change occurs in thin films containing dyes or inorganic thin films such as TeOx, and the changes are optically read out as 0s and 1s. The thin film of the present invention causes a reaction with light, heat, especially laser light commonly used for optical recording, and the thickness of the thin film changes to form bits, and this reaction also changes the refractive index of the thin film. So,
It is suggested that optical recording using this is possible. It is clear from the above explanation that the thin film of the present invention is reactive to heat, and this reactivity can be used to create partially thermally closed parts and non-ring-closed parts, and It can be patterned by removing it with a solvent. The remaining portion can be used as a resist film because it has excellent heat resistance, mechanical strength, and chemical resistance. In addition, it can be used as a cladding material for waveguides or as an optical circuit component. Patterned by the method described in resist,
Optical circuits can also be formed. In the case of the thin film of the present invention, the refractive index can be adjusted by accurately controlling the thickness and changing the compound. This is an important requirement for optical circuit components. It would be suitable as a protective coating material in all fields, and the mixture of the present invention can be used instead of fatty acids in the mixed film and laminated film method of functional LB materials and fatty acids, which are generally used in the field of LB films. By using it for various purposes, it can exhibit various functionalities, and there are many possible uses for it. For example, photoelectric conversion elements and biosensors can be created by creating films containing dyes and enzymes. It is also conceivable that this thin film could be used in the field of substance separation. Recently, there have been many attempts to use thin films with fine pores formed on porous filter substrates for material separation. If necessary, the thin film of the present invention can be prepared under conditions that preserve known Langmiur film materials, and then a thin film with fine pores can be formed by partially carrying out a ring-closing reaction. For example, a compound having a polyimide precursor structure is formed on a polyimide porous film in the presence of stearyl alcohol if necessary, and then
By imidizing at a temperature of about 200°C, a partially polyimide thin film with fine pores can be produced on a polyimide porous film. <Production of partially imidized amphoteric polyimide precursor thin film> Next, a method for forming an imide precursor film, a thin film, and a composite article containing the same will be described based on Examples. Reference Example 1 2.18 g (0.01 mol) of pyromellitic dianhydride and 5.40 g (0.02 mol) of stearyl alcohol were reacted in a flask at about 100°C for 3 hours with dry nitrogen flowing. The resulting reaction product was converted into hexamethylene phosphamide.
The mixture was dissolved in 40 c.c. and cooled to 0 to 5°C, and 2.38 g of thionyl chloride was added dropwise at about 5°C. After the dropwise addition, the mixture was maintained at about 5°C for 1 hour to complete the reaction. Then 2 g (0.01 mol) of diaminodiphenyl ether dissolved in 50 c.c. of dimethylacetamide.
was added dropwise at 0 to 5°C, and the reaction was allowed to proceed for about 1 hour after the addition, and then the reaction solution was poured into 600 c.c. of distilled water to precipitate the reaction product. The precipitated product was filtered and dried under reduced pressure at about 40°C to obtain about 9 g of pale yellow powder. The obtained powder was subjected to IR spectrum analysis and thermal analysis (TGA-
Molecular weight was measured by GPC (DTA) and GPC. IR spectrum analysis Figure 14 shows the IR spectrum measured by the KBr disk method. Ester in the IR spectrum,
Amide absorption bands, absorption bands, absorption bands, characteristic absorptions of alkyl chains and ethers appear. Thermal analysis (TGA-DTA) Measured at full scale using the RTG-DTA(H) type manufactured by Rigaku Denki Co., Ltd. with TGA 10mg, DTA 100μV, temperature 1000℃, heating rate 10℃/min, and nitrogen flow (30ml/min). The results are shown in FIG. TGA has inflection points at 271, 318, 396, and 592°C, and DTA has a characteristic peak around 657°C. In addition, Figure 16 shows that the obtained precursor was heated to 400℃.
The results are shown when the temperature was raised at 10°C/min, kept at 400°C for 1 hour, returned to room temperature, and then raised to 1000°C at 10°C/min. By keeping it at 400°C for 1 hour, the weight almost reaches a constant weight and the polyimidation reaction is completed. When this was returned to room temperature and heated again, the weight change was 450℃.
It was revealed that thermal decomposition begins at 584°C, which is the same as the thermal decomposition temperature of polyimide film, and that it is possible to obtain a product with the same heat resistance as polyimide film by terminating the polyimidation reaction. Recognize. In addition, Figure 17 shows the obtained precursor at 200℃ and 250℃.
TGA when the temperature is raised at 10°C/min to 300°C, 350°C, and kept at each temperature for 1 hour
It is. A weight loss corresponding to the imidization temperature occurs, approximately 45
%, 63%, 77%, and 98.6% imidization. Furthermore, IR spectrum analysis of the product obtained after partial imidization showed that the imidization reaction occurred in response to the imidization temperature, and the imide ring characteristic absorptions such as 1720 cm ^-1 and 1780 cm ^-1 This became clear from the degree of appearance and the degree of disappearance of absorption of long chain alkyl groups from 3000 to 2800 cm ^-1 . Figure 18 is 200
IR spectrum of the product imidized for 1 hour at °C. Molecular weight measurement by GPC The number average molecular weight calculated by comparing the GPC results measured with N,N-dimethylacetamide solvent with a polystyrene standard sample is approximately
It was 50,000. Reference Example A developing solution for LB membrane was prepared by dissolving 55.1 mg of the product of Reference Example 1 in a mixture of distilled chloroform/dimethylacetamide = 8/2 (volume ratio) to make a 25 ml solution. Using the obtained developing solution, the relationship between surface pressure π and area per repeating unit (Unit) was measured on double-distilled water at 20°C, and the results shown in FIG. 19 were obtained. The surface pressure rose rapidly from about 75 Å ² /Unit, and a good condensed film was formed. The ultimate area was 60 Å ² /Unit, and the collapse pressure was 55 dyne/cm, which are extremely high values for a polymer membrane. Furthermore, even when the membrane was held on the water surface with a surface pressure of 20 dyne/cm, no decrease in area was observed for 2 hours.
It was a stable film. Next, the surface pressure of the membrane on the water surface is 25dyne/cm at 20℃.
90 layers were accumulated on a glass substrate or CaF ₂ plate using the LB method at a cumulative speed of 10 mm/min. When the film formed on the CaF ₂ plate was analyzed by FT-ART-IR, a spectrum as shown in Figure 20 was obtained, which is the cumulative film of the compound obtained in Reference Example 1.
It was confirmed from the area-time curve that it was a Y-type film. Although the aqueous layer used in this example does not contain Cd ⁺⁺ ions, etc., the X-ray diffraction analysis of the 90-layer cumulative film shows that the peak is 2θ = 4.65°.
Only one was observed. Bragg diffraction condition nλ=2d sinθ, n=3, λ
= 1.5418Å, d (thickness of one layer) is 28.5
Å, which is almost the same as the value when the long chain alkyl groups are vertically oriented in the amphoteric polyimide precursor. Further, by heating the cumulative film at 400°C for 1 hour, an α,β-unsaturated 5-membered ring imide is produced with a temperature of 1790 cm ^-1 according to FT-ATR-IR analysis.
It was confirmed by the peak at 1710 cm ^-1 . In addition, when the product of Reference Example 1 was heated at 400°C for 1 hour, a decrease of 58% (weight%, same hereinafter) occurred.
Imidization has been confirmed by infrared absorption spectrum analysis. The above weight loss was in good agreement with the calculated value of 58.7% when stearyl alcohol disappears by imidization. Comparative Example 1 In the same manner as Reference Example 1, n-decyl alcohol (n-decyl alcohol) was used instead of stearyl alcohol.
A polyimide precursor was synthesized using C ₁₀ H ₂₁ OH). This polyimide precursor was analyzed by IR spectroscopy,
The results of thermal analysis and molecular weight measurement by GPC showed that it had almost the same characteristics as the polyimide precursor of Example 1, but the surface pressure area curve measurement result was 21.
As shown in the figure, there was no presence of a condensed phase, only a liquid expanding phase. Therefore, it has become clear that those using an alkyl group having 10 carbon atoms are too short to obtain a safe condensed phase. Reference Examples 3 to 5 Polyimide precursors were synthesized in the same manner as in Reference Example 1 using lauryl alcohol, myristyl alcohol, and cetyl alcohol having 12, 14, and 16 carbon atoms instead of stearyl alcohol (respectively, they were synthesized in Reference Examples 3 to 5). 5). When alcohols with 12 and 14 carbon atoms were used, the behavior was intermediate between that of alcohols with 10 and 18 carbon atoms, but a stable condensed phase was obtained when the aqueous phase was heated to about 5°C. For alcohols with 16 carbon atoms, the number of carbon atoms is
It was revealed that a stable condensate film similar to that in case 18 was formed. Reference Example 6 10.91g of pyromellitic dianhydride and 27.05g of stearyl alcohol were reacted at 120℃ for 3 hours, and the product was recrystallized with 200ml of ethanol to give a melting point of 133~
Distearyl pyromellitate at 137°C was obtained. 60 c.c. of this distearyl pyromellitate 3.79 g.
The solution was dissolved in hexamethylene phosphamide and cooled to 5°C, and 1.19 g of thianyl chloride was added dropwise at about 5°C. After the dropwise addition, the reaction was maintained for about 1 hour to complete the reaction. Thereafter, 1.2 g of diaminodiphenyl ether dissolved in 30 c.c. of dimethylacetamide was heated to about 10°C.
The reaction temperature was raised to about 20° C., and the mixture was reacted for 2 hours, and then poured into 400 c.c. of ethanol to precipitate the reaction product. The precipitate was filtered and dried at 40°C to obtain about 3.4 g of pale yellow powder. IR spectrum analysis, thermal analysis (TGA-DTA),
When molecular weight was measured by GPC, the following results were obtained. IR spectrum analysis IR chart taken with KBr disk method Figure 22
Characteristic absorptions of esters, amides, alkyl chains, and ethers appeared. Thermal analysis (TGA-DTA) Measured at full scale using the RTG-DTA(H) type manufactured by Rigaku Denki Co., Ltd. with TGA 10mg, DTA 100μV, temperature 1000℃, heating rate 10℃/min, and nitrogen flow (30ml/min). The results are shown in Figure 23. To TGA
There are inflection points at 203, 270, 354, 403, and 580℃,
There are no characteristic peaks in DTA. Molecular weight measurement by GPC The number average molecular weight measured using a mixed solvent of chloroform and N,N-dimethylacetamide (8:2) was about 15,000 in terms of polystyrene. Reference Example 7 55.1 mg of the product of Reference Example 6 was dissolved in a mixture of distilled chloroform/dimethylacetamide=8/2 (volume ratio) to prepare 25 ml of a developing solution for LB membrane. When the relationship between surface pressure and area per repeating unit was measured on double distilled water at 20°C, the results shown in Figure 24 were obtained. The surface pressure rose rapidly from about 65 Å ² /unit, and a good condensed film was formed. The ultimate area is about 55Å ² /unit, and the collapse pressure is
It was 45dyne/cm. (Figure 24-A) A solution of stearyl alcohol with the same molar concentration as the above solution is mixed in the same volume, and the sum of the number of repeating units of the product of Example 1 and the number of molecules of stearyl alcohol is equal to that in Figure 24-A. When the surface pressure area curve was evaluated in the following manner, the results shown in B were obtained. It can be seen that the addition of stearyl alcohol made the rise of the curve even steeper and the collapse pressure increased to approximately 60 dyne/cm, indicating that the film was stabilized. The accumulation on the glass substrate on which aluminum was vapor-deposited (glass substrate treated with silane coupling agent A-1100 or A-187) was Y-shaped regardless of whether stearyl alcohol was added, and a good accumulated film was obtained. It was done. Further, a mixture of the product of Reference Example 6 and stearyl alcohol in a 1:1 molar ratio was accumulated on a germanium substrate and heated at 400°C under a nitrogen stream for 1 hour. The disappearance and appearance of five-membered ring imides at 1790 and 1710 cm ^-1 were observed. Reference Example 8 Similar to Reference Example 7, the surface pressure area curve was evaluated using stearic acid, ω-heptadenoic acid, and octadecane instead of stearyl alcohol. It was found that the rise became steeper and the collapse pressure also increased. The collapse pressures of stearic acid and ω-heptadenoic acid were almost the same as stearyl alcohol and superior to octadecane. Further, a film to which stearic acid, ω-heptadenoic acid, and octadecane were added was accumulated in a Y-shape on a glass substrate on which aluminum was deposited, and a good accumulated film was obtained. Reference Example 9 Using the compound of Reference Example 1, a cumulative film of 1, 3, 5, 7, and 9 layers of amphoteric polyimide precursor was prepared on a glass substrate having a 0.5 mm width aluminum electrode under the same conditions. After drying this in a desiccator overnight,
A 0.1 mm wide aluminum electrode was deposited and the capacitance was measured at room temperature at a frequency of 1 KHz. FIG. 25 is a plot of the reciprocal of capacitance against the cumulative number of films. The bars indicate the dispersion of the 10 data. The loss coefficient is about 0.20 for a single layer film, but for films with 5 or more layers it is about 0.20.
It was less than 0.02, indicating good performance. Reference example 10 Compound of reference example 6 and stearyl alcohol 1:
11, 21, 31, 41, using a mixture of 1 (molar ratio)
A cumulative film of 51 layers was created. The substrate used was a glass substrate treated with silane coupling agent A-1100 (1%) on which a 0.5 mm aluminum electrode was deposited. After accumulation, it was dried overnight, treated at 400° C. for 1 hour under nitrogen flow, and an aluminum electrode with a width of 0.1 mm was deposited perpendicular to the aluminum electrode, and the capacitance was measured at room temperature at a frequency of 1 KHz. FIG. 26 shows a plot of the reciprocal of capacitance against the cumulative number of films. Bar is data 10
It shows the dispersion of Both loss coefficients are
It was around 0.02. Reference example 11 Same as reference example 10, 11, 21, 31, 41, 51,
A cumulative film of 101 and 151 layers was made and heated at 400°C for 1 hour under a nitrogen stream to form an aluminum film with a device area of 0.18 cm ² .
A polyimide thin film/aluminum device was created. The thickness of each polyimide thin film is approximately 50, 100,
They are 150, 200, 250, 500, and 700 Å. 1×10 ⁶ V/cm for each of these 10 samples,
Electric fields of 2, 3, 4, and 5×10 ⁶ V/cm were applied, but no dielectric breakdown occurred. This results in 1×
It was revealed that it has a dielectric breakdown strength of 10 ⁶ V/cm or more. Reference example 12 Polyimide thin film of approximately 100 Å is made in the same manner as reference example 10.
An aluminum/polyimide thin film/aluminum device with a device area of 0.18 cm ² was prepared and its characteristics were evaluated. The results are shown in Figures 27 and 28. It has become clear that it exhibits ohmic conductivity at electric fields up to 0.5×10 ⁶ V/cm, and above that it exhibits conductivity according to ln∝1/2. Also, Figure 12, 1
As is clear from 3, the polyimide thin film of the present invention
It is clear that it can withstand not only an electric field of 10 ⁶ V/cm but also an electric field of 10 ⁷ V/cm, as the data measured repeatedly after the experiment shown in Figure 13 almost reproduces the results of the first experiment. Ta. Example 1 A cumulative film of 11, 21, 31, and 41 layers was made in the same manner as in Reference Example 10, and heated at 200°C under a nitrogen stream for 1 hour.
A partially imidized polyimide thin film aluminum device with a device area of 0.18 cm ² was fabricated. The capacitance of this device is 1KHz
Measured at room temperature. FIG. 29 shows a plot of the reciprocal of capacitance against the cumulative number of films. Bar is data 10
The loss coefficient was approximately 0.01. Also, these thin films have 1, 2, 3, 4, 5×
An electric field of 10 ⁶ V/cm was applied, but no dielectric breakdown occurred. Effects of the Invention According to the present invention, a polymer compound modified so that it can be formed into a film by the LB film method forms a more stable film on the water surface, can be accumulated well on a substrate, and subsequently undergoes an imidization reaction. By doing this, we can create products with extremely good heat resistance, good chemical resistance, good mechanical properties, and dielectric breakdown strength of 10 ⁶ V/cm or more, which is generally difficult to create, i.e., 10,000 Å or less, or 10 to 100 Å if desired.
A variety of composite articles can be obtained, including ultra-thin films of 1000 Å.

[Brief explanation of the drawing]

Figures 1 to 7 are schematic diagrams of typical MIS structure devices, and Figures 8 to 10 are the first diagrams of the MIM structure.
Figures 1 to 13 are those of the IM structure. Figure 14 shows the IR spectrum of the precursor obtained in Reference Example 1.
FIG. 15 is a graph showing the thermogravimetric analysis (TGA-DTA) results of the precursor obtained in Reference Example 1, and FIG. 16 is a graph showing the temperature of the precursor obtained in Reference Example 1 from room temperature to 400°C. Keep it there for 1 hour, then cool to room temperature.
Figure 17 is a graph showing the thermogravimetric analysis (TGA-DTA) results when the temperature was further raised to 1000℃, and the TGA when the temperature was raised to 200, 250, 300, and 350℃ and kept at that temperature for 1 hour. The graph showing the results, Figure 18, is an IR spectrum of the compound produced by keeping it at 200°C for 1 hour. FIG. 19 is a graph showing the results of measuring the relationship between surface pressure and area per repeating unit when the precursor obtained in Reference Example 1 is spread on the water surface according to Reference Example 2. FIG. The spectrum showing the FT-ARTIR measurement results of the film developed on the water surface accumulated on a CaF ₂ plate by the LB method, and Figure 21 shows the surface pressure and per repetition unit of the precursor obtained in Comparative Example 1. A graph showing the results of measuring the relationship with area, Figure 22 shows the infrared absorption spectrum of the precursor obtained in Reference Example 6, and Figure 22 shows the infrared absorption spectrum of the precursor obtained in Reference Example 6.
Figure 3 shows the results of thermal analysis, and Figure 24 shows the surface pressure and area curves of the precursor obtained in Reference Example 6 and when it was mixed with stearyl alcohol at a molar ratio of 1:1.
Figure 25 shows the reciprocal of the capacitance of the precursor cumulative film and the cumulative number of films, Figure 26 shows the reciprocal of the capacitance of the polyimide thin film after imidization plotted against the cumulative number of precursor films, and Figures 27 and 28
The figure shows the (current) versus (voltage) characteristics of a polyimide thin film. FIG. 29 is a plot of the reciprocal capacitance of a partially imidized thin film at 200° C. versus the cumulative number of precursor films.

Claims (1)

[Claims] 1 General formula (1) (wherein R ¹ is a tetravalent group containing at least 2 carbon atoms, R ² is a divalent group containing at least 2 carbon atoms, R ³ , R ⁴ , R ⁵ and R ⁶ are Both are monovalent aliphatic groups having 1 to 30 carbon atoms, 1
A monovalent group in which a valent cycloaliphatic group or an aromatic group and an aliphatic group are bonded, and these groups are substituted with a halogen atom, a nitro group, an amino group, a cyano group, a methoxy group, or an acetoxy group. a group or a hydrogen atom, and at least one of R ³ , R ⁴ , R ⁵ and R ⁶
A composite article comprising a partially ring-closed thin film of an amphoteric polyimide precursor having repeating units of 1 to 11 carbon atoms, preferably 2 (not hydrogen atoms or hydrogen atoms). 2. The composite article of item 1, wherein the thin film is a partially ring-closed thin film obtained by accumulating a mixture of the amphoteric polyimide precursor and, if desired, a known Langmeur-Blodget film compound by the Langmeur-Blodget method. 3. The composite article of claim 1 or 2, wherein either or both of the first and second organic groups R ¹ and R ² are benzenoid groups having at least 6 carbons. 4. Paragraph 1 or Paragraph 1, in which the hydrocarbon-containing group R ³ contains an aliphatic group, a group in which a cycloaliphatic and aliphatic bond is formed, a group in which an aromatic group and an aliphatic bond are bonded, or a substituent thereof. Composite articles of Section 2. 5. The composite article according to any one of Items 1 to 4, wherein the repeating unit has a precursor structure that forms a 5-membered ring or a 6-membered ring containing a heteroatom. 6. The composite article according to any one of Items 1 to 5, wherein the hydrocarbon-containing group ^R3 has 16 to 22 carbon atoms. 7. The composite article of item 2, wherein the known Langmiur-Blodget membrane compound is a compound consisting of a hydrocarbon group having 16 to 22 carbon atoms and a hydrophilic group.