KR20070069082A - Highly adhesive polyimide film with the improved heat shrinkability - Google Patents

Abstract

A polyimide film is provided to show significantly improved adhesion as well as low shrinkability by heat. The highly adhesive polyimide film with low heat shrinkability is produced by performing an electrical discharge treatment on a polyimide film formed of paraphenylenediamine, 4,4'-diaminodiphenylether, pyromellitic dianhydride and 3,3',4,4'-biphenyltetracarbonic dianhydride, and subsequently performing a heat treatment thereon while keeping a longitudinal tension constant, wherein the highly adhesive polyimide film has a surface free energy of 80 mN/m or more, as measured on the basis of a contact angle method, and a heat shrinkage of 0.10% or less at 200 deg.C for 1 hour.

Description

Low heat shrinkage, high adhesive polyimide film {HIGHLY ADHESIVE POLYIMIDE FILM WITH THE IMPROVED HEAT SHRINKABILITY}

The present invention relates to a polyimide film with improved adhesion while improving shrinkage against heat.

Polyimide films obtained by polycondensing aromatic tetracarboxylic dianhydrides and aromatic diamines have been widely used as base films for flexible printed circuit boards because of their excellent heat resistance, insulation and mechanical properties.

When making a flexible printed board using a polyimide film as a base film, metal foils, such as copper, need to be laminated | stacked on a film via an adhesive agent, or metal should be attached directly to a film by vacuum deposition, sputtering, etc. These Since the process adds considerable heat, the polyimide film requires dimensional stability against heat. Moreover, as a recent trend, fine pitching is advanced, and polyimide films with less shrinkage by heat are required.

As a means of meeting such a request, the method (for example, refer patent document 1) of cooling a polyimide film after heat-processing substantially in a tensionless heating oven is proposed. However, the method of heat treatment under no tension is an effective method because the potential shrinkage stress of the film is alleviated and the shrinkage with respect to subsequent heating is reduced. However, in order to heat-treat under no tension, the rolled roll wound the film is heated in a heating oven. Although the method of leaving it in the air or unwinding from a roll and processing a film continuously in a continuous heating furnace provided with a winding machine is taken, since either method is processed for a long time under no tension, the film obtained becomes wavy. As a result, there was a problem that the heat shrinkage ratio became nonuniform. Moreover, especially in a continuous process, there existed a problem that a film meandered and a complete product roll was not obtained.

Moreover, in the use of the base film of a flexible printed wiring board, the carrier tape film for tape automated bonding of IC, etc., the polyimide film and copper foil are adhere | attached normally through various adhesive agents. However, due to its chemical structure and high chemical resistance, polyimide often has insufficient adhesiveness. Therefore, a method of chemically treating the film surface with an acid or an alkali (see Patent Document 1, for example) and sand Attempts to improve adhesiveness have been made in the past by performing a method of performing a physical treatment such as blasting (for example, see Patent Document 2).

However, these treatments require separate processes such as washing and drying after the treatment, and thus have problems not only in productivity, stability and cost but also in terms of environmental conservation.

Patent Document 1: Japanese Unexamined Patent Publication No. 62-41024

Patent Document 2: Japanese Unexamined Patent Publication No. 2002-294965

Patent document 3: Unexamined-Japanese-Patent No. 9-48864

The present invention has been achieved as a result of examining the problem in the above-described prior art as a problem.

Accordingly, it is an object of the present invention to provide a polyimide film having improved adhesion while improving shrinkage against heat.

In order to achieve the above object, according to the present invention, paraphenylenediamine, 4,4'-diaminodiphenyl ether, pyromellitic dianhydride and 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride A polyimide film formed of water, wherein the surface free energy measured based on the contact angle method is 80 mN / m or more, and the heat shrinkage rate at 20 ° C. and 1 hour is 0.10% or less, characterized in that Mid film is provided.

Moreover, in the low heat shrinking and high adhesive polyimide film of this invention,

The polyimide film comprises 12 to 30 mol% paraphenylenediamine, 70 to 88 mol% 4,4'-diaminodiphenyl ether, 50 to 99.5 mol% pyromellitic dianhydride and 0.5 to 50 mol% Consisting of copolymerized polyimide formed of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride of

The polyimide film has an elastic modulus of 4 to 7 GPa, a linear expansion coefficient of 5 to 20 ppm / 占 폚, a humidity expansion coefficient of 20 ppm /% RH or less, and an absorption rate of 2% or less,

The discharge treatment is a plasma discharge treatment,

The heat treatment is performed while keeping the tension in the longitudinal direction of the film constant in the range of 1 kg / m or more and 10 kg / m or less,

 All of them are mentioned as preferable conditions.

Hereinafter, the low heat shrinking and high adhesive polyimide film of this invention is demonstrated in detail.

First, in obtaining the polyimide film of this invention, the polyimide acid which is the precursor is demonstrated. The polyamic acid used in the present invention is paraphenylenediamine and 4,4'-diaminodiphenyl ether as an aromatic diamine component, pyromellitic dianhydride as an aromatic tetracarboxylic dianhydride component and 3,3 ', 4, It can obtain by superposing | polymerizing 4'-biphenyl tetracarboxylic dianhydride.

As a method until forming the polyimide film of this invention, all well-known methods, such as the method of imidating after polymerizing a polyamic acid previously, can be used. For example, all the well-known methods can be used as a manufacturing method of a polyamic acid, Usually, the polyamic-acid organic solvent solution obtained by dissolving substantial equimolar amount in aromatic organic dianhydride and aromatic diamine in an organic solvent is controlled. Under the set temperature conditions, it is prepared by stirring until the polymerization of the acid dianhydride and diamine is completed. These polyamic acid solutions can usually be obtained at a concentration of 5 to 35 wt%, preferably 10 to 30 wt%. In the case of the concentration of this range, a suitable molecular weight and solution viscosity can be obtained.

Although all well-known methods can be used as a polymerization method, the following method is mentioned as a especially preferable polymerization method. In other words,

1) A method of dissolving an aromatic diamine in an organic polar solvent and reacting this with substantially equimolar aromatic tetracarboxylic dianhydride to polymerize,

2) An aromatic tetracarboxylic dianhydride and an excessively molar amount of an aromatic diamine compound are reacted in an organic polar solvent to obtain a prepolymer having an acid anhydride group at the sock end. Next, the method of superposing | polymerizing using an aromatic diamine compound so that aromatic tetracarboxylic dianhydride and an aromatic diamine compound may become substantially equimolar in all the processes,

3) An aromatic tetracarboxylic dianhydride and an excessive molar amount of aromatic diamine compound organic polar solvent are reacted with this, and the prepolymer which has an amino group in a sock end is obtained. Subsequently, after adding an aromatic diamine compound further here, and superposing | polymerizing using aromatic tetracarboxylic dianhydride so that an aromatic tetracarboxylic dianhydride and an aromatic diamine compound may become substantially equimolar in the whole process,

4) a method in which the aromatic tetracarboxylic dianhydride is dissolved and / or dispersed in an organic polar solvent and then polymerized using an aromatic diamine compound to be substantially equimolar,

5) a method of polymerization by reacting substantially a mixture of equimolar aromatic tetracarboxylic dianhydride and aromatic diamine in an organic polar solvent,

 And the like.

In the present invention, a polyamic acid obtained by using any of the above methods may be used, and the polymerization method is not particularly limited. In this invention, the effect can of course also be acquired even if the molecular arrangement and expensive monomer in a polymer are used.

Among these methods, from the viewpoint of controlling the process stably, all of the aromatic diamine components used in all the steps are dissolved in an organic solvent, and then, an aromatic tetracarboxylic dianhydride component is added so as to be substantially equimolar, followed by polymerization reaction. It is better to use the method to carry out.

In the present invention, the aromatic tetracarboxylic dianhydride component is used in combination with pyromellitic dianhydride and 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride. Aromatic tetracarboxylic dianhydride can be used together.

As another aromatic tetracarboxylic dianhydride which can be used together, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 2,2'-bis (3,4- dicarboxyphenyl) propane dianhydride, bis (3 , 4-dicarboxyphenyl) sulfone dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, bis (3,4-carboxyphenyl) ether dianhydride, naphthalene-1,2,4,5- Tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, decahydronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 4,8-dimethyl-1,2, 3,5,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic dianhydride, 2,6, -dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,7- Dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7-tetrachloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, phenanthrene-1,8, 9,10-tetracarboxylic dianhydride, 2,2-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1- S (3,4-dicarboxyphenyl) ethane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxy Phenyl) sulfone dianhydride, benzene-1,2,3,4-tetracarboxylic dianhydride, 3,4,3 ', 4'-benzophenone tetracarboxylic dianhydride, or a mixture of two or more thereof. have.

In addition, as an aromatic diamine component, although two types of 4,4'- diamino diphenyl ether and paraphenylenediamine are used, if it is 40 mol% or less, other aromatic diamine can also be used together.

As another aromatic diamine which can be used together, 3,4'- diamino diphenyl ether, metaphenylenediamine, 4,4'- diamino diphenyl propane, 4,4'- diamino diphenylmethane, benzidine, 4 , 4'-diaminodiphenylsulfide, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 2,6-diaminopyridine, bis- (4-aminophenyl) di Ethylsilane, bis- (4-aminophenyl) diphenylsilane, 3,3'-dichlorobenzidine, bis- (4-aminophenyl) ethylphosphine oxide, bis- (4-aminophenyl) phenylphosphine oxide, bis -(4-aminophenyl) -N-phenylamine, bis- (4-aminophenyl) -N-methylamine, 1,5-diaminonaphthalene, 3,3'-dimethyl-4,4'-diamino ratio Phenyl, 3,4'-dimethyl-3 ', 4-diaminobiphenyl, 3,3'-dimethoxybenzidine, 2,4-bis ( β -amino- t -butyl) toluene, bis ( p-β- Amino- t- butylphenyl) ether, p- bis- (2-methyl-4-aminopentyl) benzene, p- bis- (1,1-dimethyl-5-aminopentyl) benzene, m- Xylenediamine, p- xylenediamine, 1,3-diaminoadamantane, 3,37-diamino-1,17-diaadamantane, 3,3'-diamino-1,1'-diaadamantane, bis ( p -aminocyclohexyl) methane, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, 3-methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine, 2,11- Diamino-dodecane, 1,2-bis- (3-aminopropoxy) ethane, 2,2-dimethylpropylenediamine, 3-methoxy-hexamethylenediamine, 2,5-dimethylhexamethylenediamine, 5-methyl Nonamethylenediamine, 5-methylnonamethylenediamine, 1,4-diamino-cyclohexane, 1,12-diamino-octadecane, 2,5-diamino-1,3,4-oxadiazole, 2, 2-bis (4-aminophenyl) hexafluoropropane, N- (3-aminophenyl) -4-aminobenzamide, 4-aminophenyl-3-aminobenzoate, and the like.

Next, as the organic solvent used for the polycondensation of polyimide in the present invention, N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylformamide, N, N-diethylacetic acid Amide, N-dimethylmethoxyacetamide, N-methyl-caprolactam, dimethyl sulfoxide, N-methyl-2-pyrrolidone, tetramethylurea, pyridine, dimethyl sulfone, hexamethylphosphoramide, tetramethylene sulfone, Formamide, N-methylformamide, butyrolactone, and the like. These organic solvents can be used alone or in combination, or in combination with a solvent having poor solubility, such as benzene, benzonitrile, dioxane, butyrolactone, xylene, toluene and cyclohexane.

In this invention, although polycondensation of polyimide can also be performed without adding a catalyst, it may be good to add the catalyst and the dehydrating agent which are enumerated below.

As the catalyst, tertiary amines are preferably used. Specific examples of these amines include trimethylamine, triethylamine, triethylenediamine, pyridine, isoquinoline, 2-ethyl pyridine, 2-methylpyridine, and N-ethylmorpholine. , N-methylmorpholine, diethylcyclohexylamine, N-dimethylcyclohexylamine, 4-benzoylpyridine, 2,4-lutidine, 2,6-lutidine, 2,4,6-corridine, 3, 4-rutidine, 3,5-lutidine, 4-methylpyridine, 3-methylpyridine, 4-isopropylpyridine, N-dimethylbenzylamine, 4-benzylpyridine, N-dimethyldodecylamine, and the like. .

Furthermore, dehydrating agents, organic carboxylic anhydrides, N, N-dialkylcarboxyimides, lower fatty acid halides, halogenated low carboxylic acid lower fatty acid halides, halogenated lower fatty acid anhydrides, arylphosphonic acid dihalogenates and thionyl halides Can be mentioned.

At this time, examples of the organic carboxylic acid anhydride include acetic anhydride, propionic anhydride, butyric anhydride, and gylic anhydride, mixtures of anhydrides mixed with each other and aromatic monocarboxylic acids such as benzoic acid, naphthoic acid, and the like, and carbonic acid. And a mixture of formic acid and fatty acid ketenes (ketene and dimethyl ketene) with anhydrides. Among them, acetic anhydride and ketene are preferred.

Besides acid anhydride, aromatic anhydrides can be used in other, o-, m- or p- toluic acid, m- or p- ethyl benzoate, propyl benzoate, p-, p- isopropyl benzoic acid, no seusan, o-, m- Or p- nitro benzoic acid, o-, m- or p- halogenobenzoic acid, various dibromo or dichloro benzoic acids, tribromo or trichloro benzoic acid, isomers of dimethyl benzoic acid, for example hemeritylic acid, 3, Acid anhydrides, such as 4-xyl acid, iso xylic acid or mesitylene acid, veratrimic acid, trimethoxy benzoic acid, α or β -naphthoic acid, biphenylcarboxylic acid, mixed anhydrides and fatty acids of the anhydrides And mixture anhydrides with anhydrides such as monocarboxylic acids such as acetic acid and propionic acid, and mixed anhydrides with respective anhydrides of carbonic acid or formic acid.

N, N'-dialkylcarboxyimides, represented by the formula: RN = C = NR wherein R may be another alkyl group, but are generally the same, and preferably the R group is from 1 to 8 carbon atoms Is a lower alkyl group.

Examples of the dehydrating agent containing halogen include acetyl chloride, acetyl bromide, acetyl iodide, acetyl fluoride, propionyl chloride, propionyl bromide, propionyl iodide, propionyl fluoride, isobutylyl bromide, isobutyl butyl bromide, and fluoride n. -Butylyl, n-butylyl iodide, bareryl chloride, mono- chloride, dichloride or trichlorochloroacetyl chloride, bromoacetyl chloride, chloroacetic anhydride, phenylphosphonic acid dichlorolide, thionyl chloride, thionyl bromide And thionyl fluoride, thionylchlorofluoride and trifluoroacetic anhydride.

Although the film forming method of the polyimide film of this invention is not specifically limited, It is common to form a film by extruding a polyamic-acid solution to a cast or film form, and drying and heat-processing to advance imidation.

At this time, it can achieve by passing the polyamic-acid solution extruded in the drying, heat processing, casting | flow_spread, or film form through 200-550 degreeC, preferably the dry heat-heat processing zone maintained in 250-500 degreeC high temperature atmosphere.

In this invention, it is good to adjust so that film thickness may be 5-150 micrometers, Preferably it is 7-125 micrometers.

The polyimide film of the present invention is 12 to 30 mol% paraphenylenediamine, 70 to 88 mol% 4,4'-diaminodiphenylether, 50 to 99.5 mol% pyromellitic dianhydride, 0.5 to 50 It is preferable to form with mol% of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride.

However, when the addition ratio of feraphenylenediamine and 4,4'- diamino diphenyl ether in a diamine component increases, 4,4'- diamino diphenyl ether becomes large, a copolymerized polyimide film will fall off, and paraphenyl Since the copolymerization polyimide film becomes harder when there are more lendiamines, it is good to set the addition ratio of both according to the use of a copolymerization polyimide film. In addition, when using the obtained copolymerized polyimide film, for example in a flexible printed circuit board, it is preferable that it is not too hard and too soft as a characteristic of a film. It is preferred that the diamine is 12 to 30 mol%.

Moreover, the polyimide film of this invention is characterized by the surface free energy measured on the basis of the contact angle method of 80 mN / m or more.

At this time, when the surface free energy of a polyimide film is less than 80 mN / m, since the adhesive improvement effect becomes inadequate, it is unpreferable. When the conditions of surface free energy satisfy | fill the said range, the copolymerization polyimide film excellent in the sliding property with copper foil can be obtained.

In addition, the polyimide film of the present invention preferably has a heat shrinkage ratio of 0.10% or less under a heating condition of 200 ° C / 1 hour, and more preferably 0.05% or less.

If the heat shrinkage exceeds 0.10%, it is not preferable because the effect of improving the shrinkage against heat is small.

Moreover, it is good that the polyimide film of this invention has a linear expansion coefficient of 5-20 ppm / degreeC, humidity expansion coefficient of 20 ppm /% RH or less, and water absorption of 2% or less in elastic modulus 4-7 GPa, 50-200 degreeC. More preferable ranges are elastic modulus of 5 to 6 GPa, linear expansion coefficient of 8 to 18 ppm / 占 폚, humidity expansion coefficient of 15 ppm / RH% or less, and water absorption of 1.8% or less.

In the polyimide film of the present invention that satisfies the above characteristics, the polyimide formed of the above composition is formed into a film, and then the copolymerized polyimide film is subjected to a discharge treatment, followed by heating while maintaining a constant tension in the longitudinal direction of the film. It can carry out by making it. As the discharge treatment in the present invention, a plasma treatment is typical.

Although the pressure of the atmosphere which performs the said plasma processing is not specifically limited, The range of 100-1000 Torr is good, More preferably, it is good to select in the pressure range of 600-90 Torr. Although it does not specifically limit as gas composition of the atmosphere which performs the said plasma processing, It is good to contain oxygen. Moreover, you may contain at least 20 mol% of rare gases. Examples of the rare gas include He, Ne, Ar, and Xe, but Ar is preferable. A rare gas may be used a mixture of CO ₂ and N ₂ or the like. The plasma irradiation time for performing the plasma treatment is preferably 1 second to 10 minutes.

Although the gas type, gas pressure, and processing density of the plasma treatment are not particularly limited, the gas pressure is preferably carried out under a pressure in the range of 13300 to 13,300 Pa. The gas that can be used to form the plasma gas preferably contains at least 50% of the inert gas. Furthermore, 80% or more, in particular 90% or more, is good. As an example of an inert gas, helium, argon, krypton, xenon, neon, radon, nitrogen, etc. are mentioned, These can be used individually or in combination of 2 or more types.

Moreover, as gas which can be mixed with an inert gas, oxygen, air, carbon monoxide. Carbon dioxide, carbon tetrachloride, chloroform, hydrogen, ammonia, carbon tetrafluorolide, trichlorofluoroethane, trifluoromethane, etc. are mentioned.

Preferred combinations of gas mixtures include argon / oxygen, argon / ammonia, argon / helium / oxygen, argon / carbon dioxide, argon / nitrogen / carbon dioxide, argon / helium / nitrogen, argon / helium / nitrogen / carbon dioxide, argon / helium, argon / Helium / acetone, helium / acetone, helium / air, argon / helium / silane. The processing power density is preferably 200 w · min / m 2 or more. More preferably, the treatment is performed at 50 w / min / m 2 or more, more preferably 100 w / min / m 2. Thus, although the gas kind, gas pressure, and processing density of a plasma process are not specifically limited, Usually, it is made in air | atmosphere.

In the heat treatment after the discharge treatment in the present invention, the obtained polyimide film is heated at a relatively low temperature and in a relatively short time while maintaining the tension in the longitudinal direction of the film at 1 kg / m or more and 10 kg / m or less. Processing is an important requirement.

The smaller the tension during the heat treatment, the lower the heat shrinkable film, but the film is meandered under the full arming force, especially during continuous winding, and the film is not wrinkled or wavy, and the nonuniformity of the heat shrinkage rate is increased. Since there exists a tendency, it is necessary to be 1 kg / m or more. Moreover, when tension exceeds 10 kg / m, since the heating low shrinkage film made into the objective of this invention cannot be obtained, it is unpreferable. Moreover, the range of preferable tension is 2 kg / m-7 kg / m.

As a means of heating at the time of heat processing, the method of irradiating far infrared rays or the method of blowing hot air is good. The polyimide film has an absorption peak in the far-infrared region, and heat treatment is performed in a very short time by irradiating far-infrared rays including this absorption wavelength. Moreover, in addition to far-infrared irradiation and hot air injection, a radiation heater can be used together and heat processing using only a radiation heater can also be performed.

Although heat processing temperature is not specifically limited, 300-500 degreeC is good, More preferably, it is 350-450 degreeC.

In addition, as for heat processing time, about 1 second-about 10 minutes are good. If the treatment time is longer than this, undesired tendency may occur because the deterioration of characteristics such as deterioration of film flatness occurs.

In this invention, it is good to heat-process after discharge treatment. By carrying out the treatment in this order, wrinkles and the like when the film is wound with moderate slipperiness are reduced.

In the present invention, the polyimide film subjected to the discharge treatment and the heat treatment is wound after the end width is slit, such as a prescribed width.

The polyimide film of the present invention thus obtained is excellent in dimensional stability against heat, shrinkage due to heat, or adhesion to copper foil is significantly improved than before, so utilizing these characteristics, the flexible flexible materials such as electronic parts As a base insulating film of TAB (Tape Automated Bonding) which is a base material used for a printed wiring board (FPC), a chip on flex (CF), or a tape for LOC which is a support member in a semiconductor device, etc. can be usefully used.

Example

Hereinafter, the present invention will be described in detail by way of examples. Each characteristic of the polyimide film in an Example was evaluated by the following method.

 (Surface free energy)

The surface free energy was calculated | required using the FACE CA-W150 by Kyowa Interface Science from the average value of the contact angle which surface-treated the film surface measured n = 5 times with water, ethylene glycol, and methylene iodide. The fact that this value is large means that water wettability is good and adhesive force is generally high.

 (Adhesive evaluation)

An adhesive mixed with an epoxy resin adhesive (trade name Epoxy AH-357A / AH -357 B / AH-357 C = 100/5/12 weight ratio) manufactured by Mitsui Chemical Co., Ltd. is coated on each film with a coater. Preliminary drying was performed at 130 degreeC x 4 minutes, and 18 micrometers rolled copper foil (BHY-22B-T, Japan Energy Co., Ltd.) was piled up, and the laminated board with copper was obtained by the presscure of 170 degreeC and 80 minutes under 2 MPa pressurization. The circuit of 0.8 mm was cut out to the obtained laminated board, and it etched by the ferric chloride solution, and the sample for evaluation was produced. The obtained 0.8 mm width metal foil part was peeled off at a peel angle of 90 ° and 50 mm / min, and was measured n = 5 times, and the average value was made into the adhesive force.

 (Thermal shrinkage measurement)

The heat shrinkage was measured, and heating conditions of 200 ° C. × 1 hour were used, and other conditions were carried out in accordance with IPC-FC-231 Number 2.2.4.

<Example 1>

253.4 g of N, N-dimethylacetamide was placed in a 50 cc glass flask, and 1.947 g of paraphenylenediamine and 3.828 g of pyromellitic dianhydride were added thereto, and the mixture was allowed to react at room temperature and atmospheric pressure for 1 hour. Next, 26.431 g of 4,4'-diaminodiphenyl ether was added thereto and stirred until uniform, followed by 8.826 g of 3,3,4,4'-biphenyltetracarboxylic dianhydride. Was added and reacted for 1 hour. Subsequently, 22.314 g of pyromellitic dianhydrides were added here, and also it made to react for 1 hour, and the polyamic-acid solution was obtained.

Acetic anhydride, isoquinoline, and N, N-dimethylacetamide were added to this polyamic acid solution, and the mixture was stirred, and then the solution was extruded on a heating support and inverted with polyimide to obtain a self-supporting film.

Next, the film was peeled from the support, and the reaction to imide was completed, and dried and heat-treated by passing through a dry heat treatment zone at 250 to 450 ° C. to form a polyimide film having a thickness of 25 μm. Wound up. Thermal contraction of the obtained film was MD: 0.12, TD: 0.15.

Subsequently, plasma treatment was performed on this polyimide film. Plasma treatment is performed at a high voltage applied between an electrode whose surface is covered by a dielectric material and which is cooled to 25 ° C. and a dielectric coating electrode supporting the polyimide film under an atmosphere of 75 Torr containing 2 mol% of rare gas. It carried out by continuously treating the surface of a film by the processing intensity of 500 w * min / m <2>.

Then, this polyimide film was continuously put into the tunnel type infrared irradiation furnace at 400 degreeC, and heat-processed by tension 1.Okg / m, and it cooled to room temperature, winding out of a furnace. The film tension during the heat treatment was adjusted by the difference in the rotational speeds of the feed roller and the winding roller, and the heat treatment time was adjusted by the relative rotational speed of each roller. After that,

About the polyimide film obtained in this way, the result of having evaluated adhesiveness and a heat shrink rate is put together in Table 1.

<Example 2>

Except having made the film thickness into 7.5 micrometers, after obtaining a polyimide film by the method similar to Example 1, the result of having evaluated adhesiveness and thermal contraction rate is put together in Table 1.

<Example 3>

248 g of dimethylacetamide was added, and 4.866 g of paraphenylenediamine and 21.215 g of 4,4'-diaminodiphenyl ether were added, followed by addition of 22.870 g of pyromellitic dianhydride, followed by further reaction for 1 hour, Next, a polyimide film was obtained in the same manner as in Example 1 except that 13.240 g of 3,3,4,4'-biphenyltetracarboxylic dianhydride was added and reacted again for 1 hour to obtain a polyamic acid solution. , The results of evaluation of adhesiveness and thermal shrinkage are summarized in Table 1.

<Example 4>

Except having made the film thickness into 7.5 micrometers, after obtaining a polyimide film by the method similar to Example 3, the result of having evaluated adhesiveness and thermal contraction rate is put together in Table 1.

Comparative Example 1

Except not performing 400 degreeC heat processing, the result of having evaluated the adhesiveness and thermal contraction rate about the polyimide film obtained by the method similar to Example 1 was put together in Table 1.

Comparative Example 2

Except not performing a plasma process, the result of having evaluated adhesiveness and thermal contraction rate about the polyimide film obtained by the method similar to Example 1 was put together in Table 1.

Comparative Example 3

Table 1 summarizes the results of evaluation of the adhesiveness and the heat shrinkage rate of the polyimide film obtained in the same manner as in Example 1 except that the heat treatment and the plasma treatment at 400 ° C were not performed.

thickness Surface free energy Heat shrinkage% Adhesive strength N / cm Comprehensive evaluation Μm mN / m MD TD Example 1 25 83 0.03 0.02 0.44 Good Example 2 7.5 85 0.02 0.02 0.43 Good Example 3 25 86 0.02 0.01 0.40 Good Example 4 7.5 84 0.03 0.02 0.42 Good Comparative Example 1 25 84 0.12 0.15 0.44 Lack of dimensional stability Comparative Example 2 25 44 0.02 0.01 0.26 Insufficient adhesion Comparative Example 3 25 43 0.15 0.13 0.25 Insufficient both dimensional stability and adhesion

The polyimide film of the present invention not only has excellent dimensional stability against heat, but also has a smaller shrinkage due to heat, and adhesion to copper foil is significantly improved than before. As a base insulating film of TAB (Tape Automated Bonding) and COF (Chip 0n Flex) which are base materials used for a board | substrate FPC, it can be usefully used as a tape for LOC which is a support member in a semiconductor device.

Claims (5)

The polyimide film formed of paraphenylenediamine, 4,4'- diamino diphenyl ether, pyromellitic dianhydride, and 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride was discharged. Then, the polyimide film is subjected to heat treatment while maintaining a constant tension in the longitudinal direction of the film, the surface free energy measured based on the contact angle method is 80 mN / m or more, 200 ℃, 1 hour The heat shrinkage rate is 0.10% or less, The low heat shrink and high adhesive polyimide film characterized by the above-mentioned. The polyimide film of claim 1, wherein the polyimide film comprises 12 to 30 mol% of paraphenylenediamine, 70 to 88 mol% of 4,4′-diaminodiphenyl ether, and 50 to 99.5 mol% of pyromellitic dianhydride. And copolymerized polyimide formed of 0.5 to 50 mol% of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride. A low heat shrinkable and highly adhesive polyimide film. The polyimide film has an elastic modulus of 4 to 7 GPa, a linear expansion coefficient of 5 to 20 ppm / ° C, a humidity expansion coefficient of 20 ppm /% RH or less, and an absorption rate of the polyimide film. It is 2% or less, The low heat shrink and high adhesive polyimide film. The low heat shrink / high adhesive polyimide film according to any one of claims 1 to 3, wherein the discharge treatment is a plasma discharge treatment. The said heat treatment is performed, maintaining the tension in the longitudinal direction of a film in the range of 1 kg / m or more and 10 kg / m or less, The said heat processing is characterized by the above-mentioned. Low heat shrink and high adhesive polyimide film.