KR101453085B1 - Polyimide resin and film - Google Patents

Abstract

TECHNICAL FIELD The present invention relates to a polyimide resin and a film comprising an imide of a polyamic acid and an indium-tin mixed oxide (ITO) obtained from a diamine and a dianhydride, and to a polyimide resin and film which are colorless and transparent and have electrical properties, mechanical properties and heat resistance Excellent polyimide resin and film can be provided.

Description

[0001] The present invention relates to a polyimide resin and film,

The present invention relates to a polyimide resin and a film.

Generally, a polyimide resin refers to a high heat-resistant resin prepared by preparing a polyamic acid derivative by combining an aromatic dianhydride with an aromatic diamine or an aromatic diisocyanate in solution, and then dehydrating and dehydrating the ring-opening at a high temperature. (PMDA) or biphenyltetracarboxylic acid dianhydride (BPDA) as the aromatic dianhydride component, and aromatic diamine components such as oxydianiline (ODA), tetracarboxylic dianhydride p-phenylenediamine (p-PDA), m-phenylenediamine (m-PDA), methylenedianiline (MDA), and bisaminophenylhexafluoropropane (HFDA).

Polyimide resin is an insoluble and non-fusible ultra-high temperature resistant resin. It has excellent heat resistant oxidizing property, heat resistance property, radiation resistance property, low temperature property, chemical resistance and so on. It is a high heat resistant material such as automobile material, , Insulating films, semiconductors, and electrode protective films for TFT-LCDs.

However, the polyimide resin is colored in brown or yellow due to its high aromatic ring density, and thus has low transmittance in the visible light region and exhibits a yellowish color, thereby lowering the light transmittance, making it difficult to use the polyimide resin in fields requiring transparency.

To solve this problem, attempts have been made to polymerize monomers and solvents with high purity, but the improvement of the transmittance is not significant.

U.S. Patent No. 5,053,480 discloses a method of using an aliphatic cyclic dianhydride component instead of an aromatic dianhydride. In comparison with the purification method, there is an improvement in transparency and color in the case of a solution phase or a film, And thus the high transmittance was not satisfied and the thermal and mechanical properties were deteriorated.

U.S. Patent Nos. 4595548, 4603061, 4645824, 4895972, 5218083, 5093453, 5218077, 5367046, 5338826. 5986036 and 6232428 and Korean Patent Laid-Open Publication No. 2003-0009437 disclose monomers having a backbone structure connected to a linking group such as -O-, -SO ₂ -, or CH ₂ - and the like at an m-position other than the p-position There has been reported a novel structure of polyimide having improved transparency and color transparency as far as the thermal property is not significantly deteriorated by using aromatic dianhydride dianhydride and aromatic diamine monomer having a substituent such as -CF ₃ , Mechanical properties, yellowing degree and visible light transmittance are not enough to be used as a substrate for a semiconductor insulating film, a TFT-LCD insulating film, an electrode protecting film, and a flexible display.

In addition, conductive films or materials containing conventional conductive carbon black or metal-based conductive fillers are virtually impossible to apply to transparent materials due to their opacity.

As such, the development of polyimide films with low yellowing was not only poor, but also pioneered in application fields. For example, a polyimide material that is colorless and conductive and has conductivity added can be used as a transparent electrode for a flexible display. The colorless transparent heat-resistant polyimide material can be used as an antistatic film, an electromagnetic wave shielding film, Etc., but it does not satisfy the physical properties required in the application field. Therefore, if the colorless and transparent characteristics are sufficiently satisfied in addition to the high heat resistance of the polyimide film, all the electronic products including the display field due to the advantages of maintaining the inherent color of the contact or adhesive product, It is likely to be applied to.

On the other hand, in order to realize the low cost, large size, light weight, and flexibility of the next generation display, attempts have been actively made to use a lighter plastic than glass as a substrate material. Further, in the case of the ITO transparent electrode, there arises a problem such as an abrupt increase of the surface resistance of the electrode due to electrode breakage due to the bending of the electrode substrate.

In recent years, development of transparent electrodes using expensive conductive materials such as carbon nanotubes in general transparent polymer materials such as silicon, nylon, acrylic, epoxy and the like has been under development, and such products are lacking in mechanical properties And the supporting film must be an expensive film having a high insulating mechanical property and a low water permeability, so that the manufacturing cost of the product is generally increased.

On the other hand, as a colorless transparent conductive film, a film formed of an indium-tin oxide film on a polyethylene terephthalate plastic film is commercially available and exhibits excellent transparency to visible light. However, since the glass transition temperature is only about 70 ° C, There is a drawback that it has a low level of heat resistance. This low level of heat resistance provides a fundamental source of durability and reliability degradation when applied to electronics. In addition, the film formed with a dry or wet indium-tin oxide film can conduct current through the surface, but it is impossible to conduct current in the thickness direction due to the non-conductive property of the base film. have. In addition, when the film of indium-tin oxide is thickened, it is difficult to apply it to electronic parts requiring ductility due to its easy breaking property. On the contrary, when the thickness is thin, the electrical resistance is increased.

Accordingly, the present invention aims to provide a polyimide resin and a film which are colorless and transparent and excellent in electrical characteristics, mechanical properties and heat resistance.

Accordingly, the present invention provides a process for producing 2,2-bis [4- (4-aminophenoxy) -phenyl] propane (6HMDA), 2,2'- Diaminobiphenyl (3,3'-TFDB), 4,4'-bis (trifluoromethyl) -4,4'-diaminobiphenyl Bis (3-aminophenoxy) diphenylsulfone (DBSDA), bis (3-aminophenyl) sulfone (3DDS), bis Benzene (APB-133), 1,4-bis (4-aminophenoxy) benzene (APB-134), 2,2'-bis [3- (3-aminophenoxy) phenyl] hexafluoropropane BDAF), at least one diamine selected from 2,2'-bis [4 (4-aminophenoxy) phenyl] hexafluoropropane (4-BDAF) and oxydianiline (ODA) (3,4-dicarboxyphenyl) hexafluoropropanediamine hydrate (FDA), 4- (2,5-dioxotetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene- 1,2-dicarboxylic anhydride (TDA), 4,4 '- (4,4 - (4,4'-oxydiphthalic dianhydride) (ODPA) and 3,4,3 ', 4 (isopropylidene diphenoxy) bis (phthalic anhydride) '' - biphenyltetracarboxylic dianhydride (BPDA) and an indium-tin mixed oxide (ITO) of polyamic acid obtained from at least one dianhydride selected from the group consisting of biphenyltetracarboxylic dianhydride (BPDA).

The polyimide resin according to this embodiment may contain 2 to 100 parts by weight of indium-tin mixed oxide (ITO) based on 100 parts by weight of the polyamic acid solid content.

The indium-tin mixed oxide (ITO) may contain 80 to 95% by weight of indium oxide (In ₂ O ₃ ) and 5 to 20% by weight of tin oxide (SnO ₂ ) .

In another preferred embodiment of the present invention, there is provided a polyimide film comprising the polyimide resin according to the above embodiment.

The polyimide film according to this embodiment may have an average transmittance of at least 70% at 380 to 780 nm when measuring the transmittance with a UV spectrometer based on a film thickness of 25 to 100 μm.

The polyimide film according to this embodiment may have a yellowness value of 15.0 or less based on a film thickness of 25 to 100 mu m.

The polyimide film according to this embodiment may have a volume resistivity of 10 ¹ to 10 ¹² Ω · cm.

The polyimide film according to this embodiment may have a surface resistance of 10 ¹ to 10 ¹² Ω / □.

The polyimide film according to this embodiment may have a volume resistivity of 10 ¹ to 10 ⁶ Ω · cm.

The polyimide film according to this embodiment may have a volume resistivity of 10 ⁶ to 10 ¹² Ω · cm.

The present invention also provides an electronic component comprising the polyimide film as another preferred embodiment.

The present invention also provides a transparent electrode comprising the polyimide film.

The present invention also provides an electromagnetic wave shielding film comprising the polyimide film.

The present invention also provides an antistatic film comprising the polyimide film.

The present invention also provides a tubular belt comprising the polyimide film.

The present invention can provide a polyimide resin and a film which can be used in fields where transparency and conductivity are required by providing a polyimide resin and a film which are colorless and transparent and excellent in electrical characteristics, mechanical properties and heat resistance.

Hereinafter, the present invention will be described in more detail.

The polyimide resin of the present invention comprises an imidized imide imidized after a polyamic acid solution which is a precursor of polyimide is obtained by copolymerization of diamines and dianhydrides, and indium-tin mixed oxide (ITO) Polyimide resin.

The colorless and transparent polyimide resin of the present invention is preferably excellent in transparency to visible light and has an average transmittance of at least 70% at 380 to 780 nm when measured with a UV spectrometer based on a film thickness of 25 to 100 μm, It is preferable that the degree is not more than 15.0.

The polyimide resin and film of the present invention having excellent transparency to the visible light can be used for applications where use of the conventional polyimide film due to yellow has been limited, that is, a protective film or a diffusion plate and a coating film for TFT- LCD can be used in fields requiring transparency such as interlayer, gate insulator, and liquid crystal alignment film. When the transparent polyimide is applied as a liquid crystal alignment film, it contributes to an increase of the aperture ratio, and thus it is possible to manufacture the TFT-LCD of ancient bevel. In addition, it can be used for a flexible display substrate. In addition, since the polyimide resin has a glass transition temperature of 200 ° C or more and excellent heat resistance, the polyimide resin does not cause dimensional change easily and does not deteriorate durability and reliability even when used in the above electronic equipment.

Dianhydrides used for this purpose include 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropanediamine hydride (FDA), 4- (2,5-dioxotetrahydrofuran- ) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride (TDA), 4,4 '- (4,4'-isopropylidene diphenoxy) bis Anhydride) (HBDA), 3,3 '- (4,4'-oxydiphthalic dianhydride) (ODPA) and 3,4,3', 4'-biphenyltetracarboxylic dianhydride BPDA). ≪ / RTI >

The diamines used in the present invention are 2,2-bis [4- (4-aminophenoxy) -phenyl] propane (6HMDA), 2,2'-bis (trifluoromethyl) Diaminobiphenyl (3,3'-TFDB), 4,4'-bis (trifluoromethyl) -4,4'-diaminobiphenyl Bis (3-aminophenoxy) diphenylsulfone (DBSDA), bis (3-aminophenyl) sulfone (3DDS), bis Benzene (APB-133), 1,4-bis (4-aminophenoxy) benzene (APB-134), 2,2'-bis [3- (3-aminophenoxy) phenyl] hexafluoropropane BDAF), 2,2'-bis [4 (4-aminophenoxy) phenyl] hexafluoropropane (4-BDAF) and oxydianiline (ODA).

The above-mentioned dianhydride and diamine are dissolved in an organic solvent in an equimolar amount and reacted to prepare a polyamic acid solution.

The solvent for the solution polymerization of the above monomers is not particularly limited as long as it is a solvent dissolving the polyamic acid. As the known reaction solvent, there may be used, for example, m-cresol, N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethylsulfoxide (DMSO) One or more polar solvents are used. In addition, a low boiling point solution such as tetrahydrofuran (THF), chloroform or a low-absorbency solvent such as? -Butyrolactone may be used.

Meanwhile, the polyimide film of the present invention includes an indium-tin mixed oxide (ITO) in order to improve the electrical characteristics. The electrical characteristics of the polyimide film can be adjusted depending on the content of the indium-tin mixed oxide, It is also possible to adjust the content of indium oxide and tin oxide by itself. The indium-tin mixed oxide (ITO) may preferably contain 80 to 95% by weight of indium oxide (In ₂ O ₃ ) and 5 to 20% by weight of tin oxide (SnO ₂ ). The indium-tin mixed oxide may be in the form of powder, and the size thereof depends on the materials used and the reaction conditions, and preferably has an average minimum diameter of 30 to 70 nm and an average maximum diameter of 60 to 120 nm.

The polyimide film of the present invention has a volume resistance of 10 ¹ to 10 ¹² Ω · cm and a surface resistance of 10 ¹ to 10 ¹² Ω / □. The volume resistivity is 10 ¹ ~ 10 ⁶ Ω · cm is may be applied as a transparent electrode or electromagnetic shielding material, transparent planar heating element materials, such ^{as, 10 6 ~ 10 12 Ω ·} cm is applicable as an antistatic material and the intermediate transfer belt for a printer have. Therefore, the polyimide film of the present invention can be applied to an intermediate transfer belt for a printer, an antistatic film, an electromagnetic wave shielding film and an electrode material requiring conductivity, which are required to have semiconducting properties.

The indium-tin mixed oxide may be dispersed in the polyamic acid solution. The indium-tin mixed oxide may include 2 to 100 parts by weight of indium-tin mixed oxide (ITO) relative to 100 parts by weight of the polyamic acid solid content. If it is contained in an amount of less than 2 parts by weight, meaningful conductivity can not be realized. If it exceeds 100 parts by weight, the ductility of the film deteriorates and it is difficult to be contained in a flexible substrate and used.

The method of adding the indium-tin mixed oxide is not particularly limited. Examples thereof include a method of adding to the polyamic acid solution before or during the polymerization, a method of kneading the indium-tin mixed oxide after the completion of the polyamic acid polymerization, A dispersion liquid containing a mixed oxide is prepared and mixed with a polyamic acid solution. At this time, the dispersion property of the indium-tin mixed oxide is influenced by the acid-basicity and viscosity of the dispersion solution, and it affects the conductivity and the uniformity of the transmittance of the visible light depending on the dispersion. Preferred dispersing methods include a three-roll mill, an ultrasonic dispersing machine, a homogenizer, and a ball mill.

The polyimide film can be prepared from the obtained polyamic acid solution by a conventionally known method. Namely, the polyamic acid solution can be imidized by casting on a support to obtain a film, but the present invention is not limited thereto.

The imidation method applicable at this time may be a thermal imidization method, a chemical imidization method or a thermal imidation method and a combination imidation method. In the chemical imidation method, a dehydrating agent represented by an acid anhydride such as acetic anhydride and a imidation catalyst represented by tertiary amines such as isoquinoline, p-picoline, and pyridine are added to a polyamic acid solution. When the thermal imidation method or the thermal imidation method and the chemical imidization method are used in combination, the heating conditions of the polyamic acid solution may be varied depending on the type of the polyamic acid solution, the thickness of the polyimide film to be produced, and the like.

More specifically, a polyimide film is prepared by adding a dehydrating agent and an imidation catalyst to a polyamic acid solution. The polyamic acid solution is cast on a support, and then heated at 80 to 200 ° C, Preferably at 100 to 180 DEG C to activate the dehydrating agent and the imidization catalyst to obtain a polyamic acid film in a gel state after peeling from the support, By heating for 400 seconds, a polyimide film can be obtained.

The thickness of the obtained polyimide film is not particularly limited, but it is preferably in the range of 10 to 250 탆, more preferably 25 to 150 탆 in consideration of the application field.

As described above, the polyimide resin and film of the present invention are colorless and transparent and have excellent electrical characteristics, and thus can be applied to substrates requiring similar electrical characteristics such as a substrate for a display device, an antistatic film, and an electromagnetic wave shielding film.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited to these Examples.

≪ Example 1 >

N, N-dimethylacetamide (DMAc) (34.1904 g) was charged into a 100 ml 3-neck round bottom flask equipped with a stirrer, a nitrogen inlet, a dropping funnel, a temperature controller and a condenser, tin mixed oxide powder (Shanghai hujeong _{nm, ITO-P100, in 2 O} 3: SnO 2 = 90: 10) 0.450g was added (5 parts by weight based on the solid content of the polyamic acid solution), an ultrasonic dispersion machine (200W, 40kHz , Manufactured by ULTEC, Korea) for 1 hour, the temperature of the reactor was lowered to 0 占 폚 and 4.1051 g (0.01 mol) of 6HMDA was dissolved and the solution was maintained at 0 占 폚. 4.4425 g (0.01 mol) of 6FDA was added thereto, and the mixture was stirred for 1 hour to completely dissolve 6FDA. At that time, the solid content was 20% by weight. After that, the solution was allowed to stand at room temperature and stirred for 8 hours. At this time, a polyamic acid solution having a solution viscosity of 850 poise at 23 ° C was obtained.

The polyamic acid solution was coated on a flat glass plate with a bar-arc coater and heated at a rate of 2 ° C / min at a temperature ranging from 40 to 400 ° C, heated at 200 ° C and 300 ° C for 30 minutes to 2 And the mixture was heated for 3 to 8 hours while being stabilized through the standstill time to obtain a polyimide film having a thickness of 50 mu m.

≪ Example 2 >

Except that 4.50 g of indium-tin mixed oxide powder (50 parts by weight with respect to the solid content in the polyamic acid solution) was added in Example 1 above.

≪ Example 3 >

Except that the mixing ratio of the indium-tin mixed oxide powder in Example 2 was changed (In ₂ O ₃ : SnO ₂ = 85: 15).

<Example 4>

Except that the diamine in Example 1 was 1,4-bis (4-aminophenoxy) benzene (Mitsui Chemicals, APB-NP) and the equivalent ratio of dianhydride and diamine was adjusted to 1: 0.998 To obtain a polyimide film.

&Lt; Comparative Example 1 &

Except that carbon black (CABOT, VULCAN XC72) was added in place of the indium-tin mixed oxide powder in Example 1.

&Lt; Comparative Example 2 &

87 g of N, N-dimethylacetamide (DMAc) was charged into a 200 ml 3-neck round-bottomed flask equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser while passing nitrogen through the reactor, Was maintained at 25 占 폚 and 6.848 g of BTDA (DICEL) was dissolved and the solution was maintained at 25 占 폚. To this was added 6.152 g of APB (Mitsui Chemicals, APB-N), and the mixture was stirred for 1 hour to completely dissolve the APB. Then, 0.450 g of an indium-tin mixed oxide powder (ITO-P100, In2O3: SnO2 = 90: 10) (an amount of 5 wt% based on the solid content in the polyamic acid solution) ), And the mixture was reacted at room temperature for 1 hour while being dispersed in the solution through an ultrasonic dispersing machine. After that, the solution was allowed to stand at room temperature and stirred for 8 hours. At this time, a polyamic acid solution having a solution viscosity of 230 poise at 23 ° C was obtained.

Then, a polyimide film was obtained in the same manner as in Example 1 above.

The polyamic acid solution containing the indium-tin mixed oxide powder before being made into a film in the above Examples and Comparative Examples was heated at a rate of 2 DEG C / min at a temperature ranging from 40 to 400 DEG C while the imidized polyimide resin Were evaluated for their physical properties by the following methods.

The properties of the polyimide films prepared in Examples and Comparative Examples were evaluated by the following methods. The results are shown in Table 1.

(1) Volume resistivity and surface resistivity

Measuring instrument: Hiresta UP, Probe UR-100 (Dia instrument)

Measuring method: Applied voltage 10V, 100V, 250V

The surface resistance unit is Ω / □ and the volume resistance unit is Ω-cm. The measurement environment is 25 ° C and 55RH%. The resistivity meter is indicated as under for 10 ⁴ Ω / □ or 10 ⁴ Ω-cm or less. Thus, a product having a resistance value of under can be applied as a conductive product.

(2) Transmittance

The transmittance of visible light (380 ~ 780nm) and 550nm wavelength was measured using a UV spectrometer (Varian, Cary100). The measurement environment is 25 ° C and 55RH%.

(3) Yellowness

The prepared film was measured for yellowness according to ASTM E313 standard using a UV spectrometer (Varian, Cary100).

(4) Volume resistivity and surface resistance for Example 2

The specific resistance value was measured using a multifunctional tester (MI-2086-EU) of METREL (Europe) for Example 2, which had a surface resistance of 10 ⁴ Ω / □ or less and a volume resistance of 10 ⁴ Ω · cm or less in Table 1 As a result, the surface resistance was 1.2 × 10 ² Ω / □ at a voltage of 1 kV, The volume resistivity was 6.2x10 &lt; ² &gt;

As a result of the physical property evaluation, the polyimide film of the present invention shows good conductivity and transparency. In the case of Example 2, the surface resistance and the volume resistance were found to be very low, and the conductivity was remarkably improved.

On the other hand, it was confirmed that the conductive polyimide film having excellent transparency obtained from the above example retained volume resistance and surface resistance even after being rolled into a tube type having a diameter of 10 mm and then spreading again. Therefore, it can be seen that the polyimide film of the present invention can be applied to a tubular belt such as an intermediate transfer belt which is continuously rotated around a plurality of rollers.

Claims (15)

Bis (trifluoromethyl) -4,4'-diaminobiphenyl, 3,3'-bis (4-aminophenoxy) Bis (3-aminophenyl) sulfone, bis (4-aminophenyl) sulfone, 4,4'-diaminobiphenyl, , 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 2,2'-bis [3- (3-aminophenoxy) phenyl] hexafluoropropane , 2,2'-bis [4 (4-aminophenoxy) phenyl] hexafluoropropane and oxydianiline, and 2,2-bis (3,4-dicarboxyphenyl) 4- (2,5-dioxotetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride, 4 , 4 '- (4,4'-isopropylidene diphenoxy) bis (phthalic anhydride), 3,3' - (4,4'-oxydiphthalic dianhydride) ',4 - and it comprises a tin mixed oxide (ITO), - biphenyltetracarboxylic dianhydride hydroxy carboxylic imide cargo and indium of the polyamic acid obtained from the selected one or more dianhydride high dry Drew of fluoride The indium-tin mixed oxide (ITO) is a polyamic acid solid content comprising 100 parts by weight of 2 to 100 parts by weight with respect to the parts of indium oxide _{(In 2 O 3) 80 ~} 95 % by weight of tin oxide (SnO ₂₎ 5 ~ 20 By weight based on the total weight of the polyimide resin. delete delete A polyimide film comprising the polyimide resin of claim 1. 5. The method of claim 4, Wherein the average transmittance at 380 to 780 nm is 70% or more when the transmittance is measured with a UV spectrometer based on a film thickness of 25 to 100 占 퐉. 5. The method of claim 4, Wherein the film has a yellow degree of 15.0 or less based on a film thickness of 25 to 100 占 퐉. 5. The method of claim 4, And a volume resistivity of 10 &lt; ¹ &gt; to 10 &lt; ¹² &gt; 5. The method of claim 4, And a surface resistance of 10 ¹ to 10 ¹² Ω / □. 8. The method of claim 7, And a volume resistivity of 10 &lt; ¹ &gt; to 10 &lt; ⁶ &gt; OMEGA .cm. 8. The method of claim 7, And a volume resistivity of from 10 ⁶ to 10 ¹² Ω · cm. An electronic part comprising the polyimide film of claim 4. A transparent electrode comprising the polyimide film of claim 9. An electromagnetic wave shielding film comprising the polyimide film of claim 9. An antistatic film comprising the polyimide film of claim 10. A tubular belt comprising the polyimide film of claim 10.