JPH01197903A - High-dielectric constant film - Google Patents

Abstract

PURPOSE:To obtain a homogeneous polymer film with high specific dielectric constant by forming it with acidic amino acid polymer containing specific cyano group. CONSTITUTION:This film is formed with acidic amino acid polymer containing the cyano group expressed by the structural formula of Formula I. Glutamic acid polymer and aspartic acid polymer are used for the polymer principal chain of this compound, a substituent with strong electron absorptivity such as cyano ethyl group, cyano phenoxyethyl group, cyano biphenocyethyl group is used for the polar functional group of a side chain. This compound is dissolved at the concentration of 1-40% in a solvent with the specific dielectric constant of 1-50, it is deployed on a substrate and made into a film then dried to obtain a thin film. A film with a high specific dielectric constant can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high dielectric constant polymer film aimed at improving the brightness of a distributed electroluminescent device and improving the performance of a large-capacity, small-sized capacitor.

Dielectric materials with high insulating properties have been used as capacitors, but as they become smaller, a material with a high dielectric constant is desired. Recently, it has also begun to be applied to various uses, such as being used as a bangu to improve the brightness of dispersed electroluminescent devices. In particular, it is known that in an electroluminescent lamp, the brightness depends on the dielectric constant of the paint, and the higher the dielectric constant, the higher the brightness. In order to improve the dielectric constant,
Although various attempts have been made in the past, it is generally believed that the magnitude of the dielectric constant of a dielectric is determined by the magnitude of its polarization.

The mode of polarization can be roughly divided into 1. electronic polarization, 2. Atomic polarization, 3. Orientation polarization, 4. Interfacial polarization can be considered. Practical research to date has mainly used orientational polarization and interfacial polarization. Examples of materials using non-oriented materials include polyvinylidene fluoride, cyanoethyl cellulose, etc., but those with a large dielectric constant have not been obtained.Also, examples using interfacial polarization As a method, there is a composite dielectric material in which fine inorganic particles with high dielectric properties, such as aluminum, are dispersed in a polymer matrix such as polyethylene.Furthermore, as a study using interfacial polarization, charge transfer complexes such as TCNQ and polycations have been investigated. Attempts have also been made to obtain compositions with high dielectric constants by mixing CT complexes with resins such as polystyrene or polysulfone.

(Japanese Unexamined Patent Publication No. 51-501GG) Composite dielectric materials using inorganic fine particles have the following drawbacks: 1. Poor adhesion between the inorganic material and the polymer, creating voids at the interface. 2. Lacking the ability to form a thin film.

3. It is thought that the mechanical strength is weak.

Furthermore, the charge transfer complex using interfacial polarization is
Frequency stability is poor and coloration is significant.

Further, as shown above, cyanoethylcellulose is used practically as a binder for electroluminescence, but as shown in the comparative example, it has the following drawbacks. 1. Poor bendability and lack of flexibility. 2
．． It lacks elongation and flexibility. 3. Poor adhesion to the electrode. 4. High water absorption and low dielectric strength.

01' of the present invention has a high relative dielectric constant, and also does not contain inorganic powder and is thermally stable in order to improve the adhesion to the glass substrate and mechanical strength, which are the drawbacks of cyanoethyl cellulose. The purpose is to obtain a uniform polymer film with a high dielectric constant by highly oriented polar groups using polyamino acids that are highly flexible and have excellent adhesion to glass.

In order to achieve such an objective, the present inventors synthesized an amino acid polymer having a functional group with a large bonding moment, such as a cyano group, in the side chain of a polyamino acid that can be expected to have a high degree of molecular orientation, and made it into a thin film. I saw things.

That is, the present invention relates to a high dielectric constant film made of an acidic amino acid polymer containing a cyano group, and is represented by the following structural formula.

The polymeric main chain of the compound of the present invention is a glutamic acid polymer,
Examples include aspartic acid polymers, and the polar functional groups in the side chains include substituents with strong electron-withdrawing properties such as cyanoethyl group, cyanophenoxyethyl group, and cyanobiphenoxyethyl group, and ester bonds to the main chain of the polymer. It is preferable that such a compound be linked with a solvent having a dielectric constant of 1 to 50, such as dimethyl sulfoxide, acetonate, etc.
- A thin film can be obtained by dissolving it in lyl, dimethylformamide, N-methylpyrrolidone, acetone, etc. at a concentration of 1-40%, spreading it on a substrate to form a film, and then drying it.

Examples of the substrate used for development include glass, metal, ceramics, release paper, and plastic films with good solvent resistance to the above-mentioned solvents.

Moreover, the compound of the present invention can be synthesized as follows.

In a solution of poly-ω-methyl acidic amino acid, P-! - Add luenesulfonic acid and an alcohol containing a cyano group in excess, stir at 60°C for 10-20 hours, and precipitate with methanol to obtain the desired compound. Here, the alcohol containing a cyano group includes ω-cyanoalkanol with an alkyl chain length of 1-5, cyanophenoxyalkanol with an alkyl chain length of 1-5, and cyanobiphenoxylene with an alkyl chain length of 1-5. Examples include alkanols. As a solvent for dissolving the poly-monomethyl acidic amino acid, dichloroethane, chloroform, dioxane, etc. are used, but dichloroethane is preferably used.

Furthermore, the thickness of the film is from 1μm to 500μm.
m is used, preferably from 5 μm to 1007 μm.
A 1 m long one is used.

The polymer thin film obtained as described above has l) a cyano group with a large binding moment in the side chain of the polyamino acid, and when the side chain has almost no polarity, for example, methyl In the case of the polar cyanoethyl group, the dielectric constant showed a much larger value than in the case of the cyanoethyl group.

2) Excellent film flexibility compared to cyanoethyl cellulose. It is useful as a single polymer binder for electroluminescence, a material for composite dielectrics, and piezoelectrics.

Example 1 10 wt.
．． 2-dichloroethane (hereinafter abbreviated as EDC) solution 326
g (0,226 mol), 107 g (0,568 mol) of p-toluenesulfonic acid-hydrate and 321 g (4,52 mol) of β-cyanoethanol were added at room temperature, and an additional 200 m of EDC was added to reduce the viscosity. l
added.

After heating to 60°C and stirring at that temperature for about 15 hours, about 100 ml of the solvent was distilled off under reduced pressure, and 170 ml of β-cyanoethanol was added. After 5 hours, the reaction solution was cooled to room temperature and slowly poured into 3.5 liters of methanol in a beaker. After filtering the precipitated product through a wire mesh,
Washed 5 times with 0 ml methanol. After washing, vacuum drying was performed to obtain 36 g of product. The degree of substitution of the cyanoethyl group was found to be 86% by NMR. 500 ml of methanol was added to the eggplant flask of Example 2 11, and 44 g of sodium hydroxide (119 mm) was added.

After dissolving 119 g of p-cyanophenol (1
mol) was added over 5 minutes. After the solution became homogeneous and stirred for 30 minutes, 150 g of β-bromoethanol (
1.2 mol) was added dropwise. Heat to 60°C, 20
After stirring for an hour, methanol was distilled off under reduced pressure. 500 ml of water was added to the residue, extracted with 11 portions of chloroform, washed three times with about 300 ml of water, the chloroform layer was dried over anhydrous magnesium sulfate, and 12
6 g of product was obtained.

10w of polygamma-methylglutamate in a 500ml three-loaf flask equipped with a Dimroth and stirring blade.
t % EDCi volume) Night 40 g (28 m
8 g (42 mmol) of luenesulfonic acid hydrate and 45.6 g (280 mmol) of the above-mentioned cyanophenoxyethanol.
was added at room temperature and an additional 100% EDC was added to reduce the viscosity.
Added ml.

The mixture was heated to 60°C and stirred for about 10 hours. The melt α was initially non-uniform, but became uniform by heating.

After the reaction was completed, the reaction solution was slowly poured into 1.51 methanol in a beaker. The precipitated product was filtered using a Buchner funnel, then redissolved in 100 ml of EDC, and then dissolved in 100 ml of EDC again.
．． The reaction solution was slowly poured into 51 methanol. After filtering the precipitated product through Buchner Lo-1,
ml (Washed 5 times with IQ methanol. After washing, vacuum drying was performed to obtain 3.8 g of product.

Comparative Example 1 The elongation of a film (thickness about 30 μm) obtained by casting cyanoethyl cellulose from a 5% acetone solution was measured. The elongation was almost O.

Example 3 The elongation of a film (thickness about 30 μm) obtained by casting from a 5% PCNG acetonitrile solution was measured. The elongation was about 50%, which was better than lycyano 7-ethylcellulose.

Example 4 5 g of PCNGo obtained in Example 1 was dissolved in 7 ml of acetonitrile at room temperature overnight to obtain a 7% solution. A suitable number of drops of this solution was placed on a release paper with a spacer placed on it, spread with a glass rod, and then placed in an oven at 80°C for about 1 hour.
After drying for 0 minutes, the film was peeled off from the release paper to obtain a film. The obtained film was cut into a size of about 1 cm x 1 cm, and the thickness was measured using a micrometer. The film thickness is 5
Point measurements were taken and the average was determined to be 70 μm. The obtained film was dried under reduced pressure in a desiccator for about 3 hours, and then gold was vapor-deposited. For gold vapor deposition, a film of approximately 1 cm x 1 cm was sandwiched between aluminum plates punched to 6 mm in diameter, and 0.0 mm was applied to both sides of the sample. Gold deposition was carried out under reduced pressure of lmmHg (with a TL flow of 3 mA for 5 minutes each).

The thickness of the gold film produced is 250A. Next, copper lead wires were connected to both sides of the gold vapor-deposited sample using a room-temperature curable silver paste, and the capacitance was determined using an impedance analyzer in vacuum, and the dielectric constant was calculated. As a result, the dielectric constant at I KHz was 27.

Example 5 26 g of PCNPhEGo obtained in Example 2 was dissolved in 3 ml of -acetone at room temperature overnight to obtain a 9% solution. Drop an appropriate amount of this solution onto a release paper with a spacer placed on it,
After developing with a glass rod, it was dried in an oven at 80°C for about 10 minutes and peeled off from the female pattern to obtain a film. After cutting the obtained film into a size of approximately 1 cm x 1 cm,
The thickness was measured using a micrometer. The film thickness was measured at 5 points and determined from the average of the measurements, and was 136 μm. The obtained film was dried under reduced pressure in a desiccator for about 3 hours, and then gold was vapor-deposited. For gold vapor deposition, a film of approximately 1 cm x 1 cm was sandwiched between aluminum plates punched to 6 mm in diameter, and 0.0 mm was applied to both sides of the sample. Under reduced pressure of lmmHg, with a current of 6 mA for 5 minutes each,
Gold vapor deposition was performed. The thickness of the produced gold thin film is 25O
It was A. Next, steel lead wires were connected to both sides of the gold vapor-deposited sample using a room-temperature curable silver paste, and the capacitance was determined using an impedance analyzer in vacuum, and the dielectric constant was calculated. As a result, the dielectric constant at IKHz was 16.

Comparative Example 2 15% EDC of PMG (polymethylglutame-1.)
An appropriate amount of the solution was dropped onto a release paper on which a spacer was placed, spread with a glass rod, dried in an oven at 80° C. for about 10 minutes, and peeled off from the release paper to obtain a film. The obtained film was cut into a size of about 1 cm x 1 cm, and the thickness was measured using a micrometer. The film thickness was measured at 5 points and determined from the average, and was 37 μm. The obtained film was dried under reduced pressure in a desiccator for about 3 hours, and then gold was vapor-deposited. For gold vapor deposition, a film of approximately 1 cm x 1 cm was sandwiched between aluminum discs punched to 6 mm diameter, and 0.05 mm was applied to both sides of the sample. Gold deposition was carried out at a current of 6 mA for 5 minutes at a reduced pressure of lmmHg. The thickness of the produced thin gold film is 2
It was 50A. Next, copper lead wires were connected to both sides of the gold vapor-deposited sample using a room-temperature curable silver paste, and the capacitance was determined using an impedance analyzer in vacuum, and the dielectric constant was calculated. As a result, the dielectric constant at I KHz was 6.

The results of the above Examples 4.5 and Comparative Examples are shown in Table 1.

Table 1 Relative permittivity 27 16 Sentence-■3 ° P M G i j
if o P V D F relative permittivity
68

Claims (1)

[Scope of Claims] A high dielectric constant film made of an acidic amino acid polymer containing a cyano group represented by the following structural formula. ▲Contains mathematical formulas, chemical formulas, tables, etc.▼