JP2008106140A - Polyimide film and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a polyimide film that has excellent running properties, adhesiveness and dimensional stability of a film and is applicable to an automatic optical inspection system (AOI) of a flexible printed circuit board (FPC) or a chip-on-film (COF) and to provide a method for producing the same. <P>SOLUTION: The polyimide film is produced mainly by imidation from p-phenylenediamine and 4,4'-diaminodiphenyl ether as diamine components and pyromellitic acid dianhydride as an acid dianhydride component and comprises 0.1-0.9 wt.% based on the weight of a film resin of inorganic particles, having particle diameters in a range of 0.01-1.5 μm, an average particle diameter of 0.05-0.7 μm and a particle size distribution in which ≥80 vol.% based on the total particles of inorganic particles having particle diameters of 0.15-0.60 μm, dispersed into the film. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polyimide film and a method for producing the same. More specifically, the added inorganic particles are not exposed and the surface state can be well controlled by generating surface protrusions in a state of being uniformly dispersed in the film, and the running property, adhesiveness and dimensional stability of the film are improved. The present invention relates to a polyimide film that is excellent and adaptable to an automatic optical inspection system (AOI) of a flexible printed circuit board (FPC) or a chip-on-film (COF), and a manufacturing method thereof.

  Polyimide films are known to have excellent properties in heat resistance, cold resistance, chemical resistance, electrical insulation, mechanical strength, etc., and electrical insulation materials for wires, heat insulating materials, flexible printed wiring boards (FPC) It is widely used as a base film of IC, a carrier tape film for IC tape automated bonding (TAB), a tape for fixing IC lead frames, and the like. Among these, in particular, in applications such as FPC, TAB carrier tape, and lead fixing tape, a polyimide film and a copper foil are usually bonded to each other through various adhesives.

  An important practical characteristic when a polyimide film is used in these applications is the slipperiness (slidability) of the film. In various film processing steps, the slidability between the film support (for example, roll) and the film and the slidability between the films are ensured, thereby improving the operability and handling in each step, This is because the occurrence of defects such as wrinkles on the film can be avoided.

  On the other hand, the flexible printed wiring board, which is the main use of polyimide film, is usually bonded to copper foil via various adhesives. Polyimide film is stable in chemical structure and chemical resistance (solvent). Since adhesiveness with copper foil is often insufficient depending on the properties, the polyimide film is currently bonded with copper foil after being subjected to surface treatment such as alkali treatment, corona treatment, plasma treatment, and sandblast treatment.

  Further, in recent finer pitches of electronic components, especially inspection of FPC, conventionally, visual inspection of line widths and foreign matters has been mainstream, but an automatic optical inspection system (AOI) has been introduced. In the past, heat-resistant films manufactured with a conventional formulation in which inorganic powder was mixed had been sufficiently satisfactory in terms of runnability, but in AOI, the inorganic powder is too large. Along with narrowing the pitch of FPC or the like, inorganic particles may be judged as foreign matters, which is a major obstacle to automatic inspection systems.

  Conventionally, as a technique for easily smoothing a polyimide film, a method of adding an inert inorganic compound (for example, alkaline earth metal orthophosphate, dibasic calcium phosphate anhydride, calcium pyrophosphate, silica, talc) to a polyamic acid (for example, Further, a method of performing plasma treatment after forming fine protrusions on the film surface with fine particles (see, for example, Patent Document 2) is known. However, these inorganic particles have a problem that they are not suitable for automatic optical inspection systems due to their large particle size.

In addition, inorganic particles having an average particle diameter of 0.01 to 100 μm are held on the polyimide surface layer by embedding a part of each particle, and a plurality of protrusions made of the exposed inorganic particles are formed on the surface of the film. A method (for example, see Patent Document 3) in which 1 × 10 to 5 × 10 ⁸ pieces / mm ² exists in a layer is known. This method is characterized in that the slippery effect is effectively obtained by actively exposing the inorganic particles on the surface and reducing the friction coefficient of the film surface, but the inorganic particles are partially exposed. For this reason, there is a problem that scratches occur on the other film surface that comes into contact with the film, resulting in poor appearance.
JP-A-62-68852 JP 2000-191810 A Japanese Patent Laid-Open No. 5-25295

  The present invention has been achieved as a result of studying the solution of the problems in the prior art described above as an issue.

  Accordingly, an object of the present invention is a polyimide that is excellent in running property, adhesion, and dimensional stability of a film and that can be applied to an automatic optical inspection system (AOI) of a flexible printed wiring board (FPC) or a chip-on-film (COF). It is in providing a film and its manufacturing method.

In order to achieve the above goal, according to the present invention, paraphenylenediamine and 4,4′-diaminodiphenyl ether as diamine components, pyromellitic dianhydride as acid dianhydride components as main components, and imidization A manufactured polyimide film having a particle size in the range of 0.01 to 1.5 μm, an average particle size of 0.05 to 0.7 μm, and a particle size of 0.15 to 0.60 μm. Inorganic particles having a particle size distribution in which 80% by volume or more of all the inorganic particles are dispersed in the film at a rate of 0.1 to 0.9% by weight per film resin weight A polyimide film is provided.

In the polyimide film of the present invention,
The proportion of each component in the polyimide film is 10-50 mol% paraphenylenediamine and 50-90 mol% 4,4'-diaminodiphenyl ether as the diamine component, and pyromellitic dianhydride as the acid dianhydride component. Consisting of 100 mol%,
The inorganic particles are contained in a ratio of 0.3 to 0.8% by weight per film resin weight;
The average particle diameter of the inorganic particles is 0.1 to 0.6 μm,
The average particle diameter of the inorganic particles is 0.3 to 0.5 μm,
The protrusions resulting from the inorganic particles are present on the film surface, the number of protrusions having a height of 2 μm or more is 5/40 cm square or less, and the film thickness is 5 to 75 μm. It is mentioned as preferable conditions.

  The method for producing a polyimide film of the present invention comprises a diamine component composed of paraphenylenediamine and 4,4′-diaminodiphenyl ether and a tetracarboxylic dianhydride component composed of pyromellitic dianhydride. After reacting in a solvent to produce a polyamic acid, imidizing it, and forming into a film, the particle diameter is in the range of 0.01 to 1.5 μm and the average particle diameter is 0.05 to Disperse inorganic particles having a particle size distribution of 0.7 μm and inorganic particles having a particle size of 0.15 to 0.60 μm in a proportion of 80% by volume or more in the same polar organic solvent as the polar organic solvent. The resulting slurry is added to the polyamic acid solution in the polyimide manufacturing process so that the inorganic particles are in a proportion of 0.1 to 0.9% by weight per resin weight. And wherein the door.

  According to the present invention, as described below, the added inorganic particles are not exposed, and surface protrusions can be generated in a state of being uniformly dispersed in the film, so that the surface state can be well controlled, and the running property of the film In addition, it is possible to obtain a polyimide film that is excellent in adhesiveness and dimensional stability and that can be applied to an automatic optical inspection system (AOI) of a flexible printed circuit board (FPC) or a chip-on-film (COF).

  Hereinafter, the present invention will be described in detail.

  First, the polyamic acid which is a precursor for obtaining the polyimide film of the present invention will be described.

  In the present invention, an aromatic tetracarboxylic dianhydride component and an aromatic diamine component, or a chemical substance composed mainly of both components is subjected to addition polymerization in an organic solvent to obtain a varnish-like polyamic acid. Paraphenylenediamine and 4,4′-diaminodiphenyl ether are used as the aromatic diamine component, and pyromellitic dianhydride is used as the main component as the aromatic tetracarboxylic dianhydride component. That is, three types of paraphenylenediamine, 4,4′-diaminodiphenyl ether, and pyromellitic dianhydride are essential components, and only these three types or a small amount of other components are added to these three types. Can be obtained. Preferably, 10-50 mol% paraphenylenediamine and 50-90 mol% 4,4'-diaminodiphenyl ether are used as the diamine component, and 100 mol% pyromellitic dianhydride is used as the acid dianhydride component. can get. If the amount of paraphenylenediamine is too large, it becomes hard, and if it is too small, it is too soft, so 1 to 70 mol% is preferable, more preferably 5 to 60 mol%, and more preferably 10 to 50 mol%. When the amount of 4,4'-diaminodiphenyl ether is too much, it becomes soft, and when it is too little, it becomes hard, so 20 to 99 mol% is preferable, 40 to 95 mol% is more preferable, and 50 to 90 mol% is more preferable.

  In the present invention, as described above, a small amount of other diamine may be added in addition to paraphenylenediamine and 4,4'-diaminodiphenyl ether. In addition to pyromellitic dianhydride, a small amount of other acid dianhydrides may be added. Specific examples of other diamines and acid dianhydrides include, but are not limited to:

(1) Acid dianhydride 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,3 ′, 3,4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4 4′-benzophenone tetracarboxylic dianhydride, 2,3,6,7-naphthalenedicarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) ether, pyridine-2,3,5 6-tetracarboxylic dianhydride, 1,2,4,5-naphthalene tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 1,4,5,8-deca Hydronaphthalenetetracarboxylic dianhydride, 4,8-dimethyl-1,2,5,6-hexahydronaphthalenetetracarboxylic dianhydride, 2,6-dichloro-1,4,5,8-naphthalenetetracarboxylic Acid dianhydride, 2,7-dichloro B-1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-tetrachloro-1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,8,9 , 10-phenanthrenetetracarboxylic dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, , 1-bis (2,3-dicarboxyphenyl) ethane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, bis ( 3,4-dicarboxyphenyl) sulfone dianhydride, benzene-1,2,3,4-tetracarboxylic dianhydride, 3,4,3 ′, 4′-benzophenone tetracarboxylic dianhydride, and the like.

(2) Diamine 3,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, metaphenylenediamine, 4,4′-diaminodiphenylpropane, 3,4′-diaminodiphenylpropane, 3,3′-diaminodiphenylpropane 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, benzidine, 4,4'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 3,3'- Diaminodiphenyl sulfide, 4,4′-diaminodiphenylsulfone, 3,4′-diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, 2,6-diaminopyridine, bis- (4-aminophenyl) diethylsilane, 3, , 3'-Dichlorobenzidine Bis- (4-aminophenyl) ethylphosphinoxide, bis- (4-aminophenyl) phenylphosphinoxide, bis- (4-aminophenyl) -N-phenylamine, bis- (4-aminophenyl) ) -N-methylamine, 1,5-diaminonaphthalene, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,4'-dimethyl-3 ', 4-diaminobiphenyl 3,3'-dimethoxybench Gin, 2,4-bis (p-β-amino-t-butylphenyl) ether, bis (p-β-amino-t-butylphenyl) ether, p-bis (2-methyl-4-aminopentyl) benzene P-bis- (1,1-dimethyl-5-aminopentyl) benzene, m-xylylenediamine, p-xylylenediamine, 1,3-diaminoadamantane, 3, '-Diamino-1,1'-diaminoadamantane, 3,3'-diaminomethyl 1,1'-diadamantane, bis (p-aminocyclohexyl) methane, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylene Diamine, decamethylenediamine, 3-methylheptamethylenediamine, 4,4'-dimethylheptamethylenediamine, 2,11-diaminododecane, 1,2-bis (3-aminopropoxy) ethane, 2,2-dimethylpropylenediamine 3-methoxyhexaethylenediamine, 2,5-dimethylhexamethylenediamine, 2,5-dimethylheptamethylenediamine, 5-methylnonamethylenediamine, 1,4-diaminocyclohexane, 1,12-diaminooctadecane, 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.

  In the present invention, specific examples of the organic solvent used for forming the polyamic acid solution include sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, N, N-dimethylformamide, N, N-diethylformamide and the like. Formamide solvents, N, N-dimethylacetamide, acetamide solvents such as N, N-diethylacetamide, pyrrolidone solvents such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone, phenol, o-, Examples thereof include phenolic solvents such as m- or p-cresol, xylenol, halogenated phenol and catechol, or aprotic polar solvents such as hexamethylphosphoramide and γ-butyrolactone, and these may be used alone or as a mixture. Desirable to use News xylene, the use of aromatic hydrocarbons such as toluene are also possible.

The polymerization method may be performed by any known method, for example,
(1) A method in which the entire amount of the aromatic diamine component is first put in a solvent, and then the aromatic tetracarboxylic acid component is added so as to be equivalent to the total amount of the aromatic diamine component and polymerized.

  (2) A method in which the whole amount of the aromatic tetracarboxylic acid component is first put in a solvent, and then the aromatic diamine component is added in an amount equal to the amount of the aromatic tetracarboxylic acid component for polymerization.

  (3) After one aromatic diamine compound is put in a solvent, the aromatic tetracarboxylic acid compound is mixed with the reaction component at a ratio of 95 to 105 mol% for the time required for the reaction, A method in which an aromatic diamine compound is added, and then an aromatic tetracarboxylic acid compound is added and polymerized so that the total aromatic diamine component and the total aromatic tetracarboxylic acid component are approximately equal.

  (4) After placing the aromatic tetracarboxylic acid compound in the solvent, the aromatic tetracarboxylic acid compound is mixed for a time required for the reaction at a ratio of 95 to 105 mol% of one aromatic diamine compound with respect to the reaction component, A method in which a carboxylic acid compound is added, and then the other aromatic diamine compound is added and polymerized so that the total aromatic diamine component and the total aromatic tetracarboxylic acid component are approximately equal.

  (5) A polyamic acid solution (A) is prepared by reacting one aromatic diamine component with an aromatic tetracarboxylic acid in a solvent so that either one becomes excessive, and the other aromatic diamine in another solvent. The polyamic acid solution (B) is prepared by reacting the component and the aromatic tetracarboxylic acid so that either one becomes excessive. A method of mixing the polyamic acid solutions (A) and (B) thus obtained to complete the polymerization. At this time, when adjusting the polyamic acid solution (A), if the aromatic diamine component is excessive, the polyamic acid solution (B) contains excessive aromatic tetracarboxylic acid component, and the polyamic acid solution (A) contains aromatic tetracarboxylic acid. When the acid component is excessive, the polyamic acid solution (B) makes the aromatic diamine component excessive, and the polyamic acid solutions (A) and (B) are combined to form the wholly aromatic diamine component and wholly aromatic compound used in these reactions. Adjustment is made so that the amount of the tetracarboxylic acid component is approximately equal.

  The polymerization method is not limited to these, and other known methods may be used.

  The polyamic acid solution thus obtained contains a solid content of 5 to 40% by weight, preferably 10 to 30% by weight, and its viscosity is 10 to 2000 Pa · s as measured by a Brookfield viscometer, preferably 100-1000 Pa · s is preferably used for stable liquid feeding. Moreover, the polyamic acid in the organic solvent solution may be partially imidized.

  The inorganic particles added to the resin in order to form protrusions on the film surface of the present invention must be insoluble in all chemical substances that come into contact in the polyimide film manufacturing process.

Preferred examples of the inorganic particles that can be used in the present invention include SiO ₂ (silica), TiO ₂ , CaHPO ₄ , and Ca ₂ P ₂ O ₇ . Among these, silica produced by a wet pulverization method such as a sol-gel method is preferably used because it is stable and physically stable in a varnish-like polyamic acid solution and does not affect the physical properties of polyimide.

  Furthermore, the fine silica powder is used as a silica slurry that is uniformly dispersed in a polar solvent such as N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, n-methylpyrrolidone, and prevents aggregation. This is preferable because it is possible. Since this slurry has a very small particle size, the sedimentation rate is low and stable. Even if it settles, it can be easily redispersed by re-stirring.

  In the present invention, the inorganic particles added to form protrusions on the surface of the polyimide film have a particle size in the range of 0.01 to 1.5 μm and an average particle size of 0.05 μm to 0.00. In the range of 7 μm, more preferably in the range of 0.1-0.6 μm, even more preferably in the range of 0.3-0.5 μm, the polyimide film is caused to have an inspection problem to an automatic optical inspection system. It can be used without causing a decrease in the mechanical properties of the film. On the other hand, if the average particle diameter is below these ranges, sufficient slipperiness to the film cannot be obtained, and if it exceeds, the inorganic particles will be judged as foreign substances by the automatic inspection system and cause trouble. It is not preferable. Moreover, since the thickness of a normal film is 5 micrometers-75 micrometers, the inorganic particle in this particle diameter range is not exposed on the surface of a polyamide film.

  The added amount of the inorganic particles is preferably 0.1 to 0.9% by weight, more preferably 0.3 to 0.8% by weight, based on the weight of the film resin. If the amount is 0.1% by weight or less, the film surface is insufficient in number of protrusions, so that sufficient slipperiness to the film cannot be obtained, the transportability is deteriorated, and the film winding shape when wound on a roll is also deteriorated. Therefore, it is not preferable. On the other hand, if it is 0.9% by weight or more, the slipperiness of the film is improved, but coarse protrusions due to abnormal aggregation of inorganic particles increase. It is not preferable because it will come.

  By forming surface protrusions with inorganic particles, the film surface area is increased, the surface is sufficiently roughened, the anchor effect is seen, and the adhesiveness is not impaired.

  Regarding the particle size distribution of the inorganic particles, it is better that the particle size distribution is narrow, that is, the proportion of particles having similar sizes in all particles is high. Specifically, all particles having a particle size of 0.15 to 0.60 μm are all present. It is preferable to occupy a ratio of 80% by volume or more in the particles. If the proportion of particles below this range and 0.15 μm or less increases, the slipperiness of the film decreases, which is not preferable. In addition, it is possible to remove coarse particles with a 5 μm cut filter or a 10 μm cut filter when feeding inorganic particles, but if the proportion of particles of 0.60 μm or more increases, the filter will frequently clog. As a result, not only process stability is impaired, but coarse aggregation of particles tends to occur, which is not preferable.

  In the film surface protrusion caused by the inorganic particles, the number of protrusions having a height of 2 μm or more is 5 pieces / 40 cm square or less, more preferably 3 pieces / 40 cm square or less, and even more preferably 1 piece / 40 cm square or less. It is desirable to be. If it is more than this, it is not preferable because the inorganic particles are judged as foreign substances by the automatic inspection system and cause trouble.

  In the present invention, a slurry in which such inorganic particles are dispersed in the same polar solvent as the organic solvent used in the production of the polyimide film is added to the polyamic acid solution in the polyimide production process, and then decyclized and removed. It is preferable to obtain a polyimide film by solvent, but after adding inorganic particle slurry to the organic solvent before polyamic acid polymerization, polyamic acid polymerization, decyclization and desolvation to obtain a polyimide film, etc. It is possible to add the inorganic particle slurry in any step before the solvent removal.

  Next, the manufacturing method of the polyimide film of this invention is demonstrated.

  As a method for forming a polyimide film, a polyamic acid solution is cast into a film and thermally decyclized and desolvated to obtain a polyimide film, and a polyamic acid solution is mixed with a cyclization catalyst and a dehydrating agent. Although a method of obtaining a polyimide film by preparing a gel film by decyclizing it and heating it to remove the solvent is mentioned, the latter is preferable because the thermal expansion coefficient of the obtained polyimide film can be kept low. .

  In the method of chemically decyclizing, first, the polyamic acid solution is prepared.

  The polyamic acid solution can contain a cyclization catalyst (imidization catalyst), a dehydrating agent, a gelation retarder, and the like.

  Specific examples of the cyclization catalyst used in the present invention include aliphatic tertiary amines such as trimethylamine and triethylenediamine, aromatic tertiary amines such as dimethylaniline, and complex such as isoquinoline, pyridine and β-picoline. Examples thereof include cyclic tertiary amines, among which at least one amine selected from heterocyclic tertiary amines is preferably used.

  Specific examples of the dehydrating agent used in the present invention include aliphatic carboxylic acid anhydrides such as acetic anhydride, propionic anhydride, and butyric anhydride, and aromatic carboxylic acid anhydrides such as benzoic anhydride, Of these, acetic anhydride and / or benzoic anhydride are preferred.

  As a method for producing a polyimide film from a polyamic acid solution, a polyamic acid solution containing a cyclization catalyst and a dehydrating agent is cast on a support from a base with a slit and formed into a film, and an imide is formed on the support. The gel film is partially advanced to form a gel film having self-supporting properties, and then peeled off from the support, heat-dried / imidized, and subjected to heat treatment.

  The polyamic acid solution is formed into a film shape through a slit-shaped die, cast on a heated support, undergoes a thermal ring-closing reaction on the support, and is supported as a gel film having self-supporting properties. It is peeled from the body.

  The support is a metal rotating drum or an endless belt, and its temperature is controlled by radiant heat from a liquid or gaseous heat medium and / or an electric heater.

  The gel film is heated to 30 to 200 ° C., preferably 40 to 150 ° C. by receiving heat from a support and / or receiving heat from a heat source such as hot air or an electric heater, and causes a ring-closing reaction, and a free organic solvent or the like. By drying the volatile matter, it becomes self-supporting and is peeled off from the support.

  The gel film peeled off from the support is usually stretched in the running direction while regulating the running speed with a rotating roll. Stretching is performed at a temperature of 140 ° C. or less at a magnification of 1.05 to 1.9 times, preferably 1.1 to 1.6 times, and more preferably 1.1 to 1.5 times. The gel film stretched in the running direction is introduced into the tenter device, and both ends in the width direction are held by the tenter clip, and stretched in the width method while running with the tenter clip.

  The film dried in the drying zone is heated for 15 seconds to 10 minutes with hot air, an infrared heater or the like. Next, heat treatment is performed for 15 seconds to 20 minutes at a temperature of 250 to 500 using hot air and / or an electric heater. It is preferable to adjust the film thickness of the resulting polyimide film to 5 to 75 μm while adjusting the draw ratio in the running direction and the draw ratio in the width direction. Even if it is thicker or thinner than this range, the film forming property is remarkably lowered, which is not preferable.

  Hereinafter, the present invention will be described using examples.

  A method for measuring various physical properties in the present invention will be described below.

[Friction coefficient (Static friction coefficient)]
The processed surfaces of the films were overlapped and measured according to JIS K-7125 (1999). That is, using a slip coefficient measuring apparatus Slip Tester (manufactured by Technonez Co., Ltd.), the film processing surfaces are overlapped with each other, a 200 g weight is placed thereon, one of the films is fixed, and the other is fixed at 100 mm / min. Tensile and friction coefficients were measured.

[Adhesive strength]
Specifically, the adhesion evaluation method is based on the method of IPC-FC-241, by bonding a polyimide film and a copper foil with a commercially available thermoplastic polyimide adhesive, fixing the film on a hard plate, and measuring. Asked.

[Automatic optical inspection (AOI)]
The base film was inspected using SK-75 manufactured by Orbotech. The case where a foreign substance and a fine particle could be distinguished was evaluated as “◯”, while the case where the size of the foreign substance and the fine particle was similar and could not be distinguished from each other was evaluated as a “x” evaluation.

[Evaluation of inorganic particles]
Using a laser diffraction / scattering type particle size distribution measuring apparatus LA-910 manufactured by HORIBA, a sample dispersed in a polar solvent was measured and analyzed, and the particle size range, average particle size, and particle size 0.15 to 0.60 μm were obtained. The occupancy ratio in all particles was read.

[Number of abnormal protrusions]
The number of protrusions having a height of 2 μm or more was counted per 40 cm square area of the film. The height is measured with a scanning laser microscope “1LM15W” manufactured by Lasertec Co., Ltd., using a Nikon 100 × lens (CF Plan 100 × / 0.95∞ / 0 EPI) in the “SURFACE1” mode. This was confirmed by photographing and analyzing the surface.

[Film thickness]
Measurements were made using Mitutoyo lightmatic (Series 318).

[Linear expansion coefficient]
TMA-50 manufactured by Shimadzu Corporation was used, and measurement was performed under the conditions of a measurement temperature range: 50 to 200 ° C. and a heating rate: 10 ° C./min.

  Next, a synthesis example of a polyamic acid solution will be described.

[Synthesis Example 1]
Prepare pyromellitic dianhydride (molecular weight 218.12) / 4,4'-diaminodiphenyl ether (molecular weight 200.24) / paraphenylenediamine (molecular weight 108.14) at a molar ratio of 100/75/25. And polymerized to a 18.5 wt% solution in DMAc (N, N-dimethylacetamide) to give a 3000 poise polyamic acid solution.

[Synthesis Example 2]
Prepare pyromellitic dianhydride (molecular weight 218.12) / 4,4'-diaminodiphenyl ether (molecular weight 200.24) / paraphenylenediamine (molecular weight 108.14) at a molar ratio of 100/70/30. And polymerized to a 18.5 wt% solution in DMAc (N, N-dimethylacetamide) to give a 3000 poise polyamic acid solution.

[Synthesis Example 3]
Prepare pyromellitic dianhydride (molecular weight 218.12) / 4,4'-diaminodiphenyl ether (molecular weight 200.24) / paraphenylenediamine (molecular weight 108.14) at a molar ratio of 100/80/20. And polymerized to a 18.5 wt% solution in DMAc (N, N-dimethylacetamide) to give a 3000 poise polyamic acid solution.

[Synthesis Example 4]
Prepare pyromellitic dianhydride (molecular weight 218.12) / 4,4'-diaminodiphenyl ether (molecular weight 200.24) / paraphenylenediamine (molecular weight 108.14) at a molar ratio of 100/50/50. And polymerized to a 18.5 wt% solution in DMAc (N, N-dimethylacetamide) to give a 3000 poise polyamic acid solution.

[Synthesis Example 5]
Prepare pyromellitic dianhydride (molecular weight 218.12) / 4,4'-diaminodiphenyl ether (molecular weight 200.24) / paraphenylenediamine (molecular weight 108.14) at a molar ratio of 100/60/40. And polymerized to a 18.5 wt% solution in DMAc (N, N-dimethylacetamide) to give a 3000 poise polyamic acid solution.

[Synthesis Example 6]
Pyromellitic dianhydride (molecular weight 218.12) / 4,4′-diaminodiphenyl ether (molecular weight 200.24) is mixed at a molar ratio of 50/50, and DMAc (N, N-dimethylacetamide) 18. Polymerization was performed with a 5% by weight solution to obtain a 3000 poise polyamic acid solution.

[Example 1]
The particle diameter of all the particles is 0.01 μm or more and 1.5 μm or less, and particles having an average particle diameter of 0.32 μm and a particle diameter of 0.15 to 0.60 μm are 87.5% by volume of silica N , N-dimethylacetamide slurry was added to the polyamic acid solution obtained in Synthesis Example 1 in an amount of 0.3% by weight per resin weight and sufficiently stirred and dispersed. To this polyamic acid solution, a conversion agent comprising acetic anhydride (molecular weight 102.09) and isoquinoline was mixed and stirred at a ratio of 50% by weight with respect to the polyamic acid solution. At this time, it prepared so that acetic anhydride and isoquinoline might be 2.0 and 0.4 molar equivalent with respect to the amic acid group of a polyamic acid, respectively. The obtained mixture was cast on a 90 ° C. stainless steel drum rotated by a T-shaped slit die to obtain a gel film having a self-supporting property of 55% by weight of residual volatile components and a thickness of about 0.05 mm. This gel film was peeled off from the drum, and both ends thereof were gripped and treated in a heating furnace at 200 ° C. for 30 seconds, 350 ° C. for 30 seconds, and 550 ° C. for 30 seconds to obtain a polyimide film having a thickness of 38 μm. The properties of the obtained polyimide film are shown in Table 1.

[Examples 2 to 7]
Example 1 except that the polyamic acid solution used, the average particle diameter of silica, the amount of silica added, and the proportion of particles having a particle diameter of 0.15 to 0.60 μm in all particles were set as shown in Table 1, respectively. The properties of the 38 μm-thick polyimide films obtained in this manner were evaluated and are shown in Table 1.

[Example 8]
The particle diameter of all the particles is 0.01 μm or more and 1.5 μm or less, and particles having an average particle diameter of 0.37 μm and a particle diameter of 0.15 to 0.60 μm are 86.5% by volume of silica N. , N-dimethylacetamide slurry was added to the polyamic acid solution obtained in Synthesis Example 1 in an amount of 0.35% by weight per resin weight and sufficiently stirred and dispersed. To this polyamic acid solution, a conversion agent comprising acetic anhydride (molecular weight 102.09) and isoquinoline was mixed and stirred at a ratio of 50% by weight with respect to the polyamic acid solution. At this time, it prepared so that acetic anhydride and isoquinoline might be 2.0 and 0.4 molar equivalent with respect to the amic acid group of a polyamic acid, respectively. The obtained mixture was cast on a 90 ° C. stainless steel drum rotated by a T-shaped slit die to obtain a gel film having a self-supporting property of 55% by weight of residual volatile components and a thickness of about 0.05 mm. This gel film was peeled off from the drum, and both ends thereof were gripped and treated in a heating furnace at 200 ° C. for 30 seconds, 350 ° C. for 30 seconds, and 550 ° C. for 30 seconds to obtain a polyimide film having a thickness of 25 μm.

  The properties of the obtained polyimide film are shown in Table 2.

[Example 9]
The rotational speed of the drum was the same as in Example 8, except that the gel film transport speed (film forming speed) after peeling from the drum was twice as fast as in Example 8 to obtain a 12.5 μm thick film. The properties of the polyimide films obtained in the same manner as in Example 8 were evaluated and are shown in Table 2.

[Example 10]
The rotational speed of the drum was the same as in Example 8, except that the gel film conveyance speed (film formation speed) after peeling from the drum was increased 4 times compared to Example 8 to obtain a film having a thickness of 7.5 μm. The properties of the polyimide films obtained in the same manner as in Example 8 were evaluated and are shown in Table 2.

[Example 11]
The rotational speed of the drum was the same as in Example 8, except that the gel film transport speed (film forming speed) after peeling from the drum was half that of Example 8, and a film having a thickness of 50 μm was obtained. The characteristics of the polyimide films obtained in the same manner as in Example 8 were evaluated and are shown in Table 2.

[Example 12]
The rotational speed of the drum was the same as in Example 8, except that the gel film transport speed (film forming speed) after peeling from the drum was 1/3 of that in Example 8, and a 75 μm thick film was obtained. The characteristics of the polyimide films obtained in the same manner as in Example 8 were evaluated and are shown in Table 2.

[Comparative Example 1]
A polyimide film having a thickness of 38 μm was obtained in the same manner as in Example 1 except that silica was not added. Properties of the obtained polyimide film were evaluated and are shown in Table 3. A film with a high coefficient of static friction and poor slip was obtained. Also, the adhesive strength was low.

[Comparative Example 2]
The particle diameter of all particles is 0.1 μm or more and 4.5 μm or less, and the average particle diameter is 1.1 μm and the particle diameter is 0.15 to 0.60 μm. , N-dimethylacetamide slurry was added to the polyamic acid solution obtained in Synthesis Example 6 by 0.2% by weight per resin weight and sufficiently stirred and dispersed. To this polyamic acid solution, a conversion agent comprising acetic anhydride (molecular weight 102.09) and isoquinoline was mixed and stirred at a ratio of 50% by weight with respect to the polyamic acid solution. At this time, it prepared so that acetic anhydride and isoquinoline might be 2.0 and 0.4 molar equivalent with respect to the amic acid group of a polyamic acid, respectively. The obtained mixture was cast on a 90 ° C. stainless steel drum rotated by a T-shaped slit die to obtain a gel film having a self-supporting property of 55% by weight of residual volatile components and a thickness of about 0.05 mm. This gel film was peeled off from the drum, and both ends thereof were gripped and treated in a heating furnace at 200 ° C. for 30 seconds, 350 ° C. for 30 seconds, and 550 ° C. for 30 seconds to obtain a polyimide film having a thickness of 38 μm.

  The properties of the obtained polyimide film are shown in Table 3. AOI inspection did not distinguish between foreign particles and fine particles, and many abnormal projections were generated. Moreover, the dimensional change was large due to the high linear expansion coefficient.

[Comparative Example 3]
31.4% by volume of particles having a particle size range of 0.01 to 0.3 μm, an average particle size of 0.08 μm, an addition amount of 0.35% by weight, and a particle size of 0.15 to 0.60 μm in all particles The properties of a 38 μm-thick polyimide film obtained in the same manner as in Comparative Example 2 except that the calcium hydrogen phosphate was used were evaluated and are shown in Table 3. A film having a high coefficient of static friction and slightly poor sliding property was obtained. Moreover, the dimensional change was large due to the high linear expansion coefficient.

[Comparative Example 4]
The ratio of the particle diameter range of 0.01 to 1.5 μm, the average particle diameter of 0.4 μm, the addition amount of 0.35% by weight, and the particle diameter of 0.15 to 0.60 μm in all the particles is 72.6% by volume. The properties of a 38 μm-thick polyimide film obtained in the same manner as in Comparative Example 2 except that the calcium hydrogen phosphate was used were evaluated and are shown in Table 3. In this example, since the occupation ratio of the particle diameter of 0.9 to 1.3 μm occupied 22.3% by volume, the number of abnormal protrusions increased. In the AOI inspection, it was difficult to distinguish between foreign substances and fine particles. Furthermore, the dimensional change was large due to the high linear expansion coefficient.

[Comparative Example 5]
A polyimide film having a thickness of 38 μm was obtained in the same manner as in Comparative Example 2 except that the polyamic acid solution obtained in Synthesis Example 1 was used. Properties of the obtained polyimide film were evaluated and are shown in Table 3. AOI inspection did not distinguish between foreign particles and fine particles, and many abnormal projections were generated.

  As is clear from the results of Tables 1 to 3, it is a polyimide film produced mainly by imidization from paraphenylenediamine and 4,4′-diaminodiphenyl ether as a diamine component and pyromellitic dianhydride as an acid dianhydride component. The powder mainly composed of inorganic particles having a particle diameter in the range of 0.01 to 1.5 μm and an average particle diameter of 0.05 to 0.7 μm is 0.1 to 0 per film resin weight. The polyimide film of the present invention uniformly dispersed in the film at a ratio of 9% by weight retains excellent slidability, dimensional stability and adhesiveness, and has a small number of projections due to coarse particles, so AOI inspection Therefore, the flexible printed wiring board (FPC) or chip-on-film which does not have a problem that the particles are judged as foreign matter and thus forms fine wiring Suitable for applications such as (COF).

  The polyimide film of the present invention has excellent film runnability, adhesion and dimensional stability, and can be applied to an automatic optical inspection system (AOI) of a flexible printed circuit board (FPC) or a chip-on-film (COF). Therefore, it is suitable for uses such as a flexible printed wiring board (FPC) and a chip-on-film (COF) that form fine wiring without any obstacle that the inorganic particles are judged as foreign matter by the AOI inspection.

Claims (8)

Paraimide diamine and 4,4′-diaminodiphenyl ether as a diamine component, and pyromellitic dianhydride as an acid dianhydride component as main components, and a polyimide film produced by imidization, having a particle size of 0. In the range of 01 to 1.5 μm, the average particle size is 0.05 to 0.7 μm, and the proportion of inorganic particles having a particle size of 0.15 to 0.60 μm is 80% by volume or more in all particles. A polyimide film characterized in that inorganic particles having an occupied particle size distribution are dispersed in the film at a ratio of 0.1 to 0.9% by weight per film resin weight. The proportion of each component in the polyimide film is 10 to 50 mol% paraphenylenediamine and 50 to 90 mol% 4,4'-diaminodiphenyl ether as a diamine component, and 100 mol% pyromellitic as an acid dianhydride component. The polyimide film according to claim 1, comprising an acid dianhydride. The polyimide film according to claim 1 or 2, wherein the inorganic particles are contained at a ratio of 0.3 to 0.8% by weight per film resin weight. The polyimide film according to claim 1, wherein the inorganic particles have an average particle diameter of 0.1 to 0.6 μm. The average particle diameter of the said inorganic particle is 0.3-0.5 micrometer, The polyimide film of any one of Claims 1-4 characterized by the above-mentioned. 6. The method according to claim 1, wherein protrusions due to the inorganic particles are present on the film surface, and the number of protrusions having a height of 2 μm or more is 5/40 cm square or less. The polyimide film as described. Film thickness is 5-75 micrometers, The polyimide film of any one of Claims 1-6 characterized by the above-mentioned. A polyamic acid is produced by reacting a diamine component composed of paraphenylenediamine and 4,4′-diaminodiphenyl ether with a tetracarboxylic dianhydride component composed of pyromellitic dianhydride in a polar organic solvent. After imidizing, when forming into a film, the particle diameter is in the range of 0.01 to 1.5 μm, the average particle diameter is 0.05 to 0.7 μm, and the particle diameter is 0.15 to 0.15 μm. A polyamic acid solution in a polyimide manufacturing process is prepared by dispersing slurry in which inorganic particles having a particle size distribution in which 0.60 μm inorganic particles occupy 80% by volume or more of all particles are dispersed in the same polar organic solvent as the polar organic solvent. The inorganic particles are added so as to have a ratio of 0.1 to 0.9% by weight per resin weight. Method for producing Li imide film.