KR101156084B1 - Black polyimide film and method for preparing the same - Google Patents

Abstract

PURPOSE: A black polyimide film and a manufacturing method thereof are provided to enhance sun shading function, electric insulation function, and uniformity of mechanical property and to reduce pin hole generation rate. CONSTITUTION: A black polyimide film is obtained by imidizing polyamic acid which is obtained from dianhydride and diamines and comprises 3.0-7.0 weight% of carbon black, 3-15 weight% of a first particle having average particle diameter of 0.1-1.0 micron, and 0.1-1.5 weight% of a second particle having average particle diameter of greater than 1.0 micron. A black polyimide film has an optical transmittance rate in visible light area of 1.0% or less and a glossiness of 60% or less. An elongation rate of the black polyamide film is 80% or greater and a surface resistance is 10 Ω or greater. A decline of intensity and elongation rate before processing corona compare to intensity and elongation rate after processing corona is less than 20%, and pin hole generation rate(number of holes/100 m^2) is less than 1.

Description

Black polyimide film and manufacturing method thereof {BLACK POLYIMIDE FILM AND METHOD FOR PREPARING THE SAME}

The present invention relates to a black polyimide film having excellent corona resistance and excellent elongation used for shielding and a method of manufacturing the same.

In general, the polyimide (PI) resin refers to a high heat-resistant resin prepared by solution polymerization of an aromatic dianhydride and an aromatic diamine or an aromatic diisocyanate to prepare a polyamic acid derivative, and then imidization by cyclization of the ring at a high temperature. In order to prepare a polyimide resin, pyromellitic dianhydride (PMDA) or biphenyltetracarboxylic dianhydride (BPDA) or the like is used as an aromatic dianhydride component, and oxydianiline (ODA), p is used as an aromatic diamine component. -Phenylene diamine (p-PDA), m-phenylene diamine (m-PDA), methylenedianiline (MDA), bisaminophenylhexafluoropropane (HFDA) and the like are used.

Polyimide resin is an insoluble and insoluble ultra high heat resistant resin, and has excellent characteristics such as heat oxidation resistance, heat resistance, radiation resistance, low temperature property, chemical resistance, and so on. It is used in a wide range of fields in electronic materials such as insulating films, semiconductors, and electrode protective films of TFT-LCDs.

In particular, in recent years, as a coverlay (coverlay) is widely used in portable electronic devices and communication devices, interest in shielding polyimide film having a light shielding function and an insulating function and excellent mechanical properties for security purposes and visual effects. It is rising.

An object of the present invention is to provide a black polyimide film having excellent light blocking function and electrical insulation function and having uniform mechanical properties, and a method of manufacturing the same.

Accordingly, the present invention provides a polyimide film obtained by imidizing a polyamic acid obtained from dianhydride and diamines as a first preferred embodiment, wherein the first particles 3 having carbon black 3.0 to 7.0 wt% and an average particle diameter of 0.3 to 1.0 μm 3 ˜15% by weight and 0.1-1.5% by weight of the second particles having an average particle diameter of more than 1.0 μm, the light transmittance in the visible region of 1.0% or less, glossiness of 60% or less, elongation of 80% or more, and surface resistance The 10 ¹⁵ Ω or more and the pinhole incidence rate (piece / 100 m 2) is 1 or less, and the drop in strength and elongation values for the strength and elongation values after corona treatment before corona treatment is within 20%, and the elongation, light transmittance and surface The resistance provides a black polyimide film, characterized in that the deviation ratio by the following formula is each within 10%.

% Deviation = (Max-Min) / Average * 100

Carbon black according to the embodiment has an average particle diameter of 1 ㎛ or less, the maximum particle size of the particles may be 10 ㎛ or less, the minimum particle size of the particles may be 20nm or more.

Carbon black according to the embodiment may have a particle size dispersion (= volume average particle diameter / number average particle diameter) of 5 or less.

The first particles and the second particles according to the embodiment may be one or more selected from the group consisting of alumina, silica, calcium phosphate and TiO ₂ .

Carbon black according to the embodiment, the content of the first particles and the second particles may be to satisfy the relationship of the first particles (% by weight) + the second particles (% by weight)> carbon black (% by weight).

The diamine according to the embodiment may be paraphenylenediamine or oxydianiline.

Black polyimide film according to the embodiment is a step of polymerizing a polyamic acid solution from dianhydrides and diamines; The carbon black, the first particles and the second particles are mixed with the polyamic acid solution, and the polyamic acid solution, the carbon black, the first particles and the second particles, and the catalyst are added to a line mixer through different lines, and then mixed. Forming a film on a support; Heat treatment to imidize; And cooling to prepare a black polyimide film.

In this case, the first particles and the second particles may be separated and introduced into different lines.

The present invention also provides a second preferred embodiment comprising the steps of: polymerizing a polyamic acid solution from dianhydrides and diamines; After mixing the carbon black, the first particles and the second particles in the polyamic acid solution, the polyamic acid solution, carbon black, the first particles and the second particles, and the catalyst are put into a line mixer through a separate line, respectively Mixing and forming a film on a support; Heat treatment to imidize; And it provides a method for producing a black polyimide film comprising the step of cooling to produce a black polyimide film.

In the black polyimide film according to the embodiment, the contents of the carbon black, the first particles, and the second particles may be 3.0 to 7.0 wt%, 3.0 to 15 wt%, and 0.1 to 1.5 wt%, respectively.

In the black polyimide film according to the embodiment, the content of carbon black, first particles, and second particles satisfies the relationship between the first particles (% by weight) + the second particles (% by weight)> carbon black (% by weight). It may be.

In the black polyimide film according to the above embodiment, the carbon black, the first particles and the second particles are each added in the form of a solution dispersed in a polar solvent, and the catalyst is acetic anhydride, isoquinoline, β-picolin or pyridine. It may be added in the form of a solution mixed in a polar solvent.

In the black polyimide film according to the above embodiment, the polar solvent may be N, N'-dimethylformamide, N, N'-dimethylacetamide, or N-methyl-pyrrolidone.

The present invention is excellent in the light shielding function and electrical insulation function, high mechanical properties, high strength and elongation of the corona treatment before the corona treatment after the corona treatment is less than 20%, the pinhole occurrence rate is reduced There is an effect that can provide a black polyimide film.

The present invention is a polyimide film obtained by imidizing a polyamic acid obtained from dianhydride and diamines, comprising: 3.0 to 7.0 wt% of carbon black, 3 to 15 wt% of first particles having an average particle size of 0.1 to 1.0 mu m, and an average particle size of 1.0. 0.1 to 1.5% by weight of the second particles larger than μm, the light transmittance in the visible region of 1.0% or less, glossiness of 60% or less, elongation of 80% or more, surface resistance of 10 ¹⁵ GPa or more, and pinhole generation rate ( / 100 square meters) is 1 or less, and the drop in strength and elongation values with respect to the strength and elongation values before corona treatment after corona treatment is within 20%,

The light transmittance, elongation and intensity of the visible light region relate to the black polyimide film having a variation ratio of 10% or less according to the following formula.

% Deviation = (Max-Min) / Average x 100

In order to provide a light shielding function, the black polyimide film of the present invention is characterized by having a light transmittance of 1.0% or less and a glossiness of 60% or less, and the lower the value, the more preferable. This enhances aesthetics in the appearance of the applied product and ensures security by blocking the inside shape.

In addition, the black polyimide film of the present invention is characterized by having a surface resistance of 10 ¹⁵ kPa or more in order to provide an electrical insulation function as a coverlay, and the surface resistance is preferably higher. When the black polyimide surface resistance satisfies 10 ¹⁵ kPa or more, it is possible to improve electrical stability of the product as a coverlay which is mainly used as a protective film of a flexible circuit.

In addition, the black polyimide film of the present invention has an elongation of 80% or more in order to provide the above-described light shielding function and at the same time to secure mechanical properties, and a decrease in strength and elongation of the strength and elongation values before corona treatment after corona treatment. By less than 20%, characterized in that the pinhole generation rate (open / 100㎡) is 1 or less, the process stability during production and processing of the product can be improved and the mechanical reliability of the final product can be improved.

In addition, the black polyimide film of the present invention may have a light transmittance, an intensity, and an elongation of the visible light region within 10% of the deviation ratio according to the following formula in terms of securing uniformity of mechanical properties.

% Deviation = (Max-Min) / Average * 100

When the deviation ratio is within 10%, it is possible to minimize the occurrence of tolerances when the product is put into the flexible printed circuit board (FPCB) manufacturing process.

In order to achieve the physical properties of the black polyimide film as described above, the black polyimide film is 3.0 to 7.0% by weight of carbon black, 3 to 15% by weight of the first particles having an average particle diameter of 0.1 to 1.0㎛, and an average particle diameter of 1.0㎛ 0.1 to 1.5% by weight of the second particles in excess, carbon black, the first particles and the second particles may be prepared by mixing the film after mixing using a line mixer in the film forming process.

When the content of the carbon black is less than 3% by weight, the transmittance of the visible light region is increased, and when the content of the carbon black is more than 8% by weight, the light blocking function may be improved, but there may be a problem of poor insulation.

The carbon black has an average particle diameter of 1 μm or less, a maximum particle diameter of 10 μm, and a minimum particle size of 20 nm of particles, thereby minimizing a decrease in mechanical and electrical properties of the resin used as a material of the black polyimide film. .

In addition, the carbon black has a particle size dispersion (= volume average particle diameter / number average particle diameter) of 5 or less, more preferably 3 or less, the lower the particle size dispersion is the phenomenon that the carbon black particles are entangled when used. It is less, the particle size uniformity is high, the uniform dispersion is made in the interior of the resin, it can be uniformly mixed when mixing with the resin. Accordingly, degradation of mechanical properties of the film can be minimized, and uniformity of overall physical properties, that is, minimization of color deviation for each position can be achieved, and in particular, the elongation of the film can be greatly improved. In addition, the particle size dispersion of the carbon black can be improved through milling and dispersant application. At this time, it is preferable that the milling treatment is performed for each of the carbon black, the first particles, and the second particles, respectively, thereby improving the particle dispersity of the carbon black, the first particles, and the second particles.

The first particles and the second particles are used for running, quenching, and corona resistance of the black polyimide film, and when the total content of the first particles and the second particles is less than 4% by weight, the shielding rate, corona resistance, and The matting characteristic is lowered. At this time, the second particles are particles that affect the running and glossiness of the film, it is preferable that 0.1 wt% to 1.5 wt% is added. When the second particle exceeds 1.5% by weight, the mechanical properties of the film, in particular, the elongation is lowered and the pinhole incidence is increased when the film is manufactured, so that there is a problem in product yield and appearance quality deterioration. It is necessary to limit to 0.1 to 1.5% by weight.

The first particle according to the embodiment is preferably an average particle diameter of 0.1 ~ 1.0㎛, more preferably an average particle diameter of 0.3 ~ 1.0㎛.

The second particles according to the embodiment may have an average particle diameter of more than 1.0 μm, and an average particle diameter of more than 1.0 μm to 10 μm. If the average particle diameter of the second particles exceeds 10㎛ it is not preferable because other physical properties of the film is lowered.

The first particles and the second particles may be one or more selected from the group consisting of alumina, silica and TiO ₂ .

The content of the carbon black, the first particles and the second particles preferably satisfies the relationship of the first particles (% by weight) + the second particles (% by weight)> carbon black (% by weight). In the case where the first particles and the second particles are included in more than carbon black, which is a conductive material, corona resistance may be improved.

On the other hand, the black polyimide film according to the present invention, the light transmittance, elongation, and intensity of the visible light region, the ratio of the deviation according to the following formula, each within 10%, can exhibit uniform physical properties.

% Deviation = (Max-Min) / Average * 100

As such, the black polyimide film may exhibit uniform physical properties due to the mixing timing, the mixing method, and the mixing degree of the carbon black, the first particles, and the second particles during the manufacturing process of the black polyimide film.

That is, in the process of producing a black polyimide film through a step of polymerizing a polyamic acid solution from a dianhydride and diamines and forming a polyamic acid solution, carbon black, first particles and By mixing the second particle and the catalyst with the polyamic acid solution to form a film, the carbon black, the first particle and the second particle can be more uniformly mixed with the polyamic acid solution. Accordingly, the produced black polyimide film exhibits a deviation ratio as described above, and may eventually have uniform mechanical, optical, and electrical properties.

At this time, the mixing in the film forming step may be mixed by using a line mixer, by mixing the polyamic acid solution, carbon black, the first particles and the second particles, and the catalyst to the line mixer, respectively, into one inlet It is possible to mix more uniformly by preventing agglomeration which may occur due to simultaneous feeding. On the other hand, when carbon black and particles (first particles, second particles) are mixed in the step of polymerizing the polyamic acid solution, the mixing ability of the large-capacity stirrer used in the polymerization process is relatively low, thereby achieving uniform physical properties of the film. There is a difficult problem.

The dianhydrides usable in the present invention may include biphenylcarboxylic dianhydrides or derivatives thereof and pyromellitic dianhydrides or derivatives thereof. Specifically, the dianhydride is 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, 3,3'4,4'-benzophenonetetracarboxylic anhydride, p- Although phenylene bis trimellitic dianhydride etc. can be used, it is preferable to use 3,3 ', 4,4'-biphenyl tetracarboxylic dianhydride and a pyromellitic dianhydride. Particularly, in the present invention, when pyromellitic dianhydride and 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride are used among the dianhydrides, physical properties such as light transmittance, glossiness, volume resistance and the like described above It is possible to reduce the decrease in mechanical properties due to the carbon black and silica added to improve.

Diamines usable in the present invention may include phenylenediamine or derivatives thereof and diophenyl ether or derivatives thereof. Specifically, diamines include p-phenylene diamine, 4,4'-diaminophenyl ether, 3,4-diaminophenyl ether, 2,4-diaminophenyl ether and the like. Generally, p-phenylenediamine and 4,4'-diaminophenyl ether are used to improve mechanical properties.

In order to improve the coefficient of thermal expansion and modulus with respect to 1 mol of all diamines, the ratio of p-phenylene diamine may be used so that it may become 0.8-0.1 mol ratio. p-phenylene diamine is a monomer having a linearity compared to diamino phenyl ether serves to lower the coefficient of thermal expansion of the film (Coefficient of thermal expansion). However, if the content of p-phenylene diamine is high, the flexibility of the film may be reduced and the film forming ability may be lost.

As a method of manufacturing the black polyimide film of the present invention, a method of forming a polyimide film can generally be used, but a line black mixer is formed by adding carbon black, first particles, and second particles to a polymerized polyamic acid solution. And the film forming method characterized by mixing.

That is, the method for producing a black polyimide film of the present invention comprises the steps of: polymerizing a polyamic acid solution from dianhydrides and diamines; The carbon black and the first particles and the second particles are mixed with the polyamic acid solution, and the polyamic acid solution, the carbon black, the first particles and the second particles, and the catalyst are added to a line mixer through different lines, respectively, and mixed. Forming a film on a support; Heat treatment to imidize; And cooling to prepare a black polyimide film.

To give an example thereof, first, the dianhydride and diamine are reacted with an organic solvent to obtain a polyamic acid solution. At this time, the solvent is generally preferably an aprotic polar solvent (Aprotic solvent) as the amide solvent, for example, N, N'- dimethylformamide, N, N'- dimethylacetamide, N-methyl -Pyrrolidone, and the like, and may be used in combination.

The input form of the monomer may be added in the form of powder, lump, and solution. In the initial stage of the reaction, the monomer may be added in the form of powder, and the reaction may be performed in the form of a solution to control the polymerization viscosity.

The weight of the monomer added in the total polyamic acid solution with substantially equal molar amount of diamine and dianhydride is called solid content, and the polymerization is preferably carried out in the range of 10-30% or 12-23% solid content. .

The polyamic acid solution is mixed with the catalyst and applied to the support. The catalyst used is preferably a dehydration catalyst or tertiary amines composed of anhydrous acid. Examples of anhydrous acids include acetic anhydride and examples of tertiary amines include isoquinoline, β-picolin, pyridine and the like.

The amount of anhydrous acid can be calculated by the molar ratio of o-carboxylic amide functional group in the polyamic acid solution, and is preferably used in a molar ratio of 1: 1.0 to 5.0.

The amount of tertiary amine can be calculated by the molar ratio of o-carboxylic amide groups in the polyamic acid solution, and it is appropriate to add a molar ratio of 1: 0.2 to 3.0.

The catalyst can be used in the form of a mixture of anhydrous acid / amines or anhydrous acid / amine / solvent mixture.

remind The carbon black, the first particles and the second particles may be pre-milled to improve particle dispersion, and then uniformly mixed with the polyamic acid solution in a line mixer with a catalyst.

Although the carbon black, the first particles and the second particles may be mixed in the form of particles, the carbon black, the first particles, and the second particles may be mixed in the form of a solution dispersed in the aprotic polar solvent, respectively, so that the mixture is more uniformly mixed.

The applied film is gelled on the support by dry air and heat treatment. The gelation temperature conditions of the coated film is preferably 100 ~ 250 ℃ and may be used as a support, glass plate, aluminum foil, circulating stainless belt, stainless drum.

The treatment time required for gelation depends on the temperature, the type of support, the amount of polyamic acid solution applied, and the mixing conditions of the catalyst and is not limited to a certain time. Preferably it is good to perform in the range between 1 minute and 30 minutes and the residual solvent content of the gel film is 30% or less.

The gelled film is separated from the support and heat treated to complete drying and imidization. The heat treatment temperature is between 100 ~ 600 ℃ and the treatment time is between 1 to 30 minutes. The gelled film proceeds by being fixed to a support during heat treatment. Gel film can be fixed using a pin type frame or a clip type.

The residual volatile content of the film after heat treatment is 3% by weight or less, preferably 1% by weight or less.

After the heat treatment, the film is heat treated under a constant tension to remove residual stress in the film. Since the tension and temperature conditions are correlated with each other, the tension conditions may vary with temperature. The temperature is preferably maintained between 100 and 500 ° C., the tension is 50N or less, and the time is preferably maintained between 1 minute and 1 hour.

Hereinafter, the present invention will be described in detail through Examples and Comparative Examples.

Example  One

The black polyimide film was prepared according to the following method according to the carbon black content, silica particle (first particle and second particle) content, and carbon black and mixing timing of the first particle and the second particle.

As a polyamic acid solution polymerization process, 181.2 kg of N, N'-dimethylformamide (DMF) was added to a 300L reactor under a nitrogen atmosphere as a solvent. The temperature was 30 degreeC, and 20.64 kg of 4,4'- diamino phenylene ether (ODA) was added as diamine. After stirring for about 30 minutes to confirm that the monomer was dissolved, 21.81 kg of pyromellitic dianhydride (PMDA) was added thereto. After the addition, the mixture was stirred for 1 hour while maintaining the temperature to complete the first reaction. When the first reaction was completed, the temperature of the reactor was raised to 40 ° C, 0.67 kg of 8% PMDA solution was added, and the temperature was maintained for 2 hours. During stirring, the inside of the reactor was depressurized to about 1 Torr to remove bubbles in the polyamic acid solution generated during the reaction to complete the polyamic acid solution polymerization process.

Completed polyamic acid solution has a solid content of 18.5% by weight and a viscosity of 2500 poise at room temperature.

The milled carbon black, the first particles and the second particles are introduced into the mixing process of the varnish and the catalyst solution in the film forming process and mixed. At this time, in order to uniformly mix, the polyamic acid solution, the catalyst solution, and the carbon black solution And the dispersion solution of the first particles and the second particles were added to the line mixer and mixed.

In addition, the contents of the charged carbon black and silica were 5% by weight of carbon black, 4.0% by weight of the first particles, and 1.3% by weight of the second particles, based on the total polyimide film.

The average particle diameter of carbon black is 279 nm, and the average particle diameter of the first particle and the second particle is respectively 0.5 and 3.7 μm.

The polyamic acid solution and the catalyst solution (catalyst ratio: isoquinoline = 7.2, acetic anhydride = 22.4, DMF = 18.7, carbon black = 0.83, first particle = 0.66 and second particle = 0.21) are uniform in a ratio of 100/50. The mixture was cast to an endless belt at 100 μm, dried at a temperature range of 100 ° C. to 200 ° C., and then the film was peeled off the endless belt and transferred to a high temperature tenter.

The film was heated from 200 ° C. to 600 ° C. in a high temperature tenter and then cooled to separate the film from the pins to obtain a 12 μm thick film.

The strength, elongation, light transmittance, glossiness, surface resistance, dielectric breakdown strength and pinhole incidence of the black polyimide film obtained by the above method were measured, and the results are shown in Table 2 below. In addition, the deviation ratio of elongation, light transmittance and intensity is calculated and shown in Table 3.

Example 2

Carbon black was prepared in the same manner as in Example 1 except that 5.5 wt%, 6.0 wt% of the first particles, and 1.0 wt% of the second particles were used.

Example 3

Carbon black was prepared in the same manner as in Example 1 except that 6.0 wt% of the first particles and 8.0 wt% of the second particles were used.

Comparative example  1 and Comparative example  2

A black polyimide film was prepared in the same manner as in Example 1, except that the contents of the carbon black, the first particles, and the second particles shown in Table 1 were used.

Comparative Example 3 and Comparative Example 4

According to the content of the carbon black, the first particles and the second particles shown in Table 1 to prepare a black polyimide film, the carbon black, the first particles and the second particles as a mixing time, carbon black, first particles and second The particles were added and mixed after completion of the first reaction in the polymerization step, and the black polyimide film was prepared in the same manner as in Example 1 except that only the catalyst was added to the polyamic acid solution and mixed.

Carbon black
(weight%) First particle
(weight%) Second particle
(weight%) With carbon black,
Mixing timing of the first particle and the second particle Example 1 5.0 4.0 1.3 Filmmaking process Example 2 5.5 6.0 1.0 Filmmaking process Example 3 6.0 8.0 1.0 Filmmaking process Comparative Example 1 8.0 1.0 2.5 Filmmaking process Comparative Example 2 5.5 1.0 0.5 Filmmaking process Comparative Example 3 8.0 1.0 2.5 Polymerization process Comparative Example 4 5.5 1.0 0.5 Polymerization process

The physical properties of the Examples and Comparative Examples of the present invention prepared as described above were measured as follows, and the results are shown in Table 2.

Strength and elongation

It is measured using an Instron 3365SER instrument according to ASTM D 882 measurement method.

Width and Grip Thickness: 15mm * 50mm

Cross Head Speed: 200mm / min

Light transmittance in the visible region

Measure in transmission mode using Hunter Lab (model name: CQX3391).

Glossiness

Measure at 60 degree angle using glossiness measuring equipment.

Equipment: Gloss meter

Model Name: E406L

Manufacturer: Elcometer

Surface resistance

The resistance is measured under 500V using a high resistance measuring instrument (4339B, Agilent Technologies).

Pinhole incidence

A defect detector (Wintryless Co., Ltd.) calculates the number of pinhole frequencies per 100 m2 by driving a film width of 0.6 m and a product length of 1,000 m on an installation winder.

Dielectric breakdown strength

It is measured by using dielectric breakdown test equipment (6CC250-5 / D149, Phenix Technologies) according to ASTM D 149 test standard.

Carbon
black
(weight%) First particle
(weight%) Second particle
(weight%) Elongation
(%) burglar
(MPa) Light transmittance
(%) Glossiness
(%) Surface resistance
(Ω) Isolation
Breaking strength
(kV / 0.5mil) Pinhole
Incidence
(Pcs / 100㎡) Example 1 5.0 4.0 1.3 119 240 0.0 35 6.1 x 10 ¹⁵ 1.3 0.4 Example 2 5.5 6.0 1.0 118 238 0.0 30 5.2 x 10 ¹⁵ 1.2 0.3 Example 3 6.0 8.0 1.0 110 231 0.0 24 3.7 x 10 ¹⁵ 1.2 0.1 Comparative Example 1 8.0 1.0 2.5 98 220 0.0 28 1.2 x 10 ¹⁴ 0.8 1.7 Comparative Example 2 5.5 1.0 0.5 110 225 0.1 62 1.1 x 10 ¹⁵ 0.9 1.3 Comparative Example 3 8.0 1.0 2.5 80 210 0.0 28 1.2 x 10 ¹⁴ 0.8 2.5 Comparative Example 4 5.5 1.0 0.5 85 220 0.1 60 2.1 x 10 ¹⁴ 0.9 1.5

Carbon black
(weight%) First particle
(weight%) Second particle
(weight%) Elongation
Deviation Rate Light transmittance
Deviation Rate burglar
Deviation Rate Example 1 5.0 4.0 1.3 4% 3% 5% Example 2 5.5 6.0 1.0 5% 4% 5% Example 3 6.0 8.0 1.0 6% 6% 8% Comparative Example 3 8.0 1.0 2.5 20% 11% 19% Comparative Example 4 5.5 1.0 0.5 25% 15% 26%

* How to calculate the deviation ratio value

Deviation Rate = (Max-Min) / Average * 100

Strength and elongation measurement before and after corona treatment

Using the corona discharge treatment apparatus (model CT1234, Osaka Gasura Co., Ltd.), after performing the corona treatment at 4kW output to the black polyimide film prepared in Examples 1 to 3 and Comparative 1, the strength and elongation measurement The strength and elongation after corona treatment were measured according to the method, which is shown in Table 4 below.

Carbon black
(weight%) First particle
(weight%) Second particle
(weight%) Elongation
(%)I'm Elongation
(%)after burglar
(MPa) burglar
(MPa) after Example 1 5.0 4.0 1.3 119 114 240 235 Example 2 5.5 6.0 1.0 118 114 238 235 Example 3 6.0 8.0 1.0 110 110 231 230 Comparative Example 1 8.0 1.0 2.5 98 43 220 158 Comparative Example 2 5.5 1.0 0.5 110 80 235 185 Comparative Example 3 8.0 1.0 2.5 80 40 210 153 Comparative Example 4 5.5 1.0 0.5 85 55 230 180

Claims (14)

As a polyimide film obtained by imidating the polyamic acid obtained from dianhydride and diamines,
3.0 to 7.0 wt% of carbon black, 3 to 15 wt% of the first particles having an average particle size of 0.1 to 1.0 μm, and 0.1 to 1.5 wt% of the second particles having an average particle diameter of more than 1.0 μm. 1.0% or less, glossiness is 60% or less, elongation is 80% or more, surface resistance is 10 ¹⁵ GPa or more, and after the corona treatment, the strength and elongation values of the strength and elongation before corona treatment are less than 20%. , The pinhole occurrence rate (piece / 100㎡) is 1 or less,
The elongation, light transmittance and intensity are within 10% of the deviation ratio by the formula [(maximum value-minimum value) / average value * 100], respectively.
Black polyimide film characterized in that the content of the carbon black, the first particles and the second particles satisfy the relationship of the first particles (% by weight) + the second particles (% by weight)> carbon black (% by weight) .
The black polyimide film of claim 1, wherein the carbon black has an average particle diameter of 1 μm or less, a maximum particle size of 10 μm, and a minimum particle size of 20 nm.
The black polyimide film of claim 2, wherein the carbon black has a particle size dispersion (= volume average particle size / number average particle diameter) of 5 or less.
The black polyimide film of claim 1, wherein each of the first particles and the second particles is at least one selected from the group consisting of alumina, silica, calcium phosphate, and TiO ₂ .
The black polyimide film of claim 1, wherein the total content of the first particles and the second particles is 4 to 16.5 wt%.
delete The black polyimide film according to claim 1, wherein the diamine is paraphenylenediamine or oxydianiline.
The method of claim 1,
Polymerizing a polyamic acid solution from dianhydrides and diamines;
The carbon black, the first particles and the second particles are mixed with the polyamic acid solution, and the polyamic acid solution, the carbon black, the first particles and the second particles, and the catalyst are each added to the line mixer in a line mixer. Mixing and then forming a film on a support;
Heat treatment to imidize; And
The black polyimide film, characterized in that prepared by the method comprising the step of producing a black polyimide film by cooling.
The method of claim 8,
The carbon black, the first particles and the second particles are each added in the form of a solution dispersed in a polar solvent,
The catalyst is a black polyimide film, characterized in that the addition of acetic anhydride, isoquinoline, β- picoline or pyridine in the form of a solution mixed with a polar solvent.
Polymerizing a polyamic acid solution from dianhydrides and diamines;
After mixing the carbon black, the first particles and the second particles in the polyamic acid solution, the polyamic acid solution, carbon black, the first particles and the second particles, and the catalyst are put into a line mixer through a separate line, respectively Mixing and forming a film on a support;
Heat treatment to imidize; And
Cooling to prepare a black polyimide film,
In the black polyimide film, the contents of the carbon black, the first particles, and the second particles are 3.0 to 7.0% by weight, 3 to 15% by weight, and 0.1 to 1.5% by weight, respectively.
The content of the carbon black, the first particles and the second particles satisfy the relationship of the first particles (% by weight) + the second particles (% by weight)> carbon black (% by weight). Method for producing a black polyimide film.
delete delete The method of claim 10,
The carbon black, the first particles and the second particles are each added in the form of a solution dispersed in a polar solvent,
The catalyst is a method for producing a black polyimide film, characterized in that the addition of acetic anhydride, isoquinoline, β- picoline or pyridine in the form of a solution mixed with a polar solvent.
14. The polar solvent according to claim 13, wherein the polar solvent is N, N'-dimethylformamide, N, N'-dimethylacetamide, or N-methyl-pyrrolidone as an aprotic polar solvent, or a combination of two of them. Method for producing a black polyimide film, characterized in that.