JP2005226026A - Polyimide film roll - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyimide film roll wound on a core tube, having a thickness of as thin as 1-30 μm and, nevertheless, windable in ≥7,000 layers without generating deformation and crease of the film such as skewing and unevenness and provide a polyimide film roll free from the generation of the deformation and crease on the film sheet delivered from the roll. <P>SOLUTION: The polyimide film roll is produced by winding a polyimide film on a core tube in ≥7,000 layers, and has a thickness of 1-30 μm and an elastic modulus of 3.5-4.5 GPa. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a roll-shaped polyimide film obtained by being wound around a core.

   Polyimide is known to have excellent properties such as heat resistance, cold resistance, chemical resistance, electrical insulation, and mechanical strength. Electrical insulation film, heat insulation film, flexible printed wiring board base film Widely used. Especially in applications such as flexible wiring boards and electrical insulation films, specifically, polyimide films are bonded to copper foil via adhesives to form copper-clad laminates, or prepregs are formed by adhesive coating, It is often used for applications such as compounding. In such applications, there is an increasing demand for thinning, but when it becomes a thin film, particularly a polyimide film of 25 μm or less, the film tends to stretch during winding, and deformation such as distortion of the film roll and unevenness due to shrinkage after winding. Prone to wrinkles and wrinkles. In addition, the film repeatedly expands and contracts due to temperature changes during storage and transportation, and film roll deformation and wrinkles are likely to occur. Thus, when the deformation | transformation and wrinkle of a film roll generate | occur | produced, as a result, a wrinkle and a type | mold will be attached also to the film single leaf, and the external appearance defect might be caused.

Even if the roll-shaped polyimide film is stored for a long period of time, there is no defect in the appearance and roll shape of the roll, and for the purpose of suppressing vertical wrinkles of the film, winding breakage during transportation, wrinkles, etc. Discloses that a sheet material for packaging made of a metal material is disposed outside the roll. This is intended to suppress the occurrence of deformation and wrinkles by wrapping the roll itself with a metal material, which is different from the solution of the present invention. Moreover, attention is not paid to the relationship between the relatively thin polyimide film of 1 to 30 μm, which is wound 7,000 times or more around the core, and the deformation or wrinkle generated in that case and the elastic modulus of the film to be wound. .
JP 2002-370788 (Claim 1, Examples 1 and 2)

  In the roll-shaped polyimide film obtained by being wound around the core, even if the thickness of the polyimide film is as thin as 1 to 30 μm, even if it is wound more than 7000 times on the core, the film distortion or unevenness It is an object of the present invention to provide a roll-shaped polyimide film in which neither deformation nor wrinkle is generated in a roll-shaped polyimide film in which deformation or wrinkle does not occur, and furthermore, a film single leaf after being fed out of the roll.

This invention can solve the said subject with the following novel roll-shaped polyimide films.
1) A roll-shaped polyimide film obtained by winding a polyimide film around a core, the number of windings is 7000 or more, and the polyimide film has a thickness of 1 to 30 μm, and the elastic modulus of the film A roll-shaped polyimide film, which is 3.5 GPa to 4.5 GPa.
2) The roll-like polyimide film according to 1), wherein the polyimide film has a linear expansion coefficient of 10 to 20 ppm.
3) The roll-shaped polyimide film according to 1) or 2), wherein the width of the polyimide film is 250 mm or more.
4) The roll-shaped polyimide film according to 1) to 3), wherein the diameter of the core is 70 mm or more and 250 mm or less.

  According to the present invention, in a roll-shaped polyimide film obtained by being wound on a winding core, even if the thickness of the polyimide film is as thin as 1 to 30 μm, the film is wound on the winding core as many as 7000 turns or more. In addition, a roll-shaped polyimide film that does not generate deformation, wrinkles, or distortion of the film can be obtained.

  The roll-shaped polyimide film of the present invention is obtained by winding a thin polyimide film having a film thickness of 1 to 30 μm around a winding core in an amount of 7000 or more times. Until now, when the polyimide film with a small thickness is made into a roll shape, it tends to be stretched at the time of winding, or to be distorted or uneven in the rolled polyimide film due to shrinkage after winding, A product having a large number of windings such as a winding number of 7000 or more is considered difficult to manufacture. However, as a result of examining various properties of the polyimide film to be wound, the present inventors have prevented the film roll from being deformed and wrinkled even when the film is wound many times by controlling the elastic modulus of the film to a constant value. Found to be effective. That is, in the present invention, the elastic modulus of the polyimide film wound around the core is 3.5 to 4.5 GPa. When the elastic modulus of the film is smaller than 3.5 GPa, the film is easily stretched by the tension at the time of winding the film, and in the film roll after winding, the film shrinks and causes deformation such as distortion and unevenness. As a result, a single leaf and a wrinkle are formed on the film. On the contrary, when the elastic modulus of the film is larger than 4.5 GPa, the flexibility that is characteristic of the thin film is lost, and the film becomes difficult to use, which is not preferable.

  In the present invention, the polyimide film wound around the core is a film having a thickness in the range of 1 to 30 μm. When the thickness exceeds 30 μm, the rigidity of the film becomes high, and the occurrence of vertical wrinkles, which is the subject of the present invention, is small. Therefore, this invention remarkably exhibits the effect when it is a thinner polyimide film. Preferably, the polyimide film has a thickness of 7.5 to 29 μm. More preferably, it is 10-27 micrometers. The polyimide film of the present invention may be a film having a thickness variation in the width direction. In a roll of a film having a thickness variation in the width direction of 1% or more of the average thickness, deformation of the roll due to the thickness variation occurs. Therefore, the effect of the present invention is remarkable, which is a preferred embodiment.

  The polyimide film according to the present invention is obtained from various known raw materials and is not particularly limited. Mainly using organic tetracarboxylic dianhydride and organic diamine as raw materials, each component is substantially used. It is obtained via a polyamic acid varnish obtained by using equimolar amounts and polymerizing in an organic solvent solution.

The polyamic acid varnish will be described.
To the polyamic acid varnish of the present invention, fillers such as calcium hydrogen phosphate, silica, mica, titanium oxide, alumina, and glass beads may be added for the purpose of stably forming a polyimide film.

The polymerization reaction is not limited by a known method. As an example of the polymerization method, one or two diamines are diffused in an organic solvent in a solution or slurry in an inert gas atmosphere such as argon or nitrogen. At least one tetracarboxylic dianhydride is added to this solution in a solid state, an organic solvent solution state or a slurry state to obtain a polyamic acid varnish. The reaction temperature at this time is −20 ° C. to 50 ° C., preferably 20 ° C. or less. The reaction time is preferably 1 to 6 hours.
In this reaction, contrary to the order of addition, tetracarboxylic dianhydride is first dissolved or diffused in an organic solvent, and a solution or slurry of the diamine solid or organic solvent is added to the solution. Also good. Moreover, you may make it react simultaneously, and the addition order of a tetracarboxylic dianhydride component and a diamine component is not limited.
Polymerization of polyamic acid is generally carried out in two stages. In the first stage, a low-viscosity polyamic acid called a prepolymer is polymerized, and then a tetracarboxylic dianhydride or diamine compound is dissolved in an organic solvent. A highly viscous polyamic acid is obtained while adding a solvent. When shifting from the first stage to the second stage, a process for removing undissolved raw materials and mixed foreign substances in the prepolymer with a filter or the like is provided to reduce foreign substances and defects in the film. The aperture of the filter is preferably 1/2, preferably 1/5, and more preferably 1/10 of the thickness of the obtained film.
The weight% of the polyamic acid in the organic solvent is preferably 5-40 wt%, preferably 10-30 wt%, more preferably 13-25 wt% of the polyamic acid dissolved in the organic solvent from the viewpoint of handling. The average molecular weight of the polyamic acid is preferably in the range of 10,000 to 1,000,000, more preferably in the range of 50,000 to 500,000, and most preferably in the range of 100,000 to 500,000 in terms of polyethylene glycol by GPC measurement. . If it is outside this range, if the molecular weight is low, the R value in the measurement of tear propagation resistance and the retention ratio of the tear propagation resistance after standing for 12 hours in an environment of 100% RH at 150 ° C. As a result, the film mechanical strength and adhesiveness are not satisfied. Further, when the molecular weight is high, the handleability is poor and the productivity is greatly reduced.

  Examples of the organic solvent used for the polymerization of the polyamic acid include ureas such as tetramethylurea, N, N-dimethylethylurea, sulfoxides or sulfones such as dimethylsulfoxide, diphenylsulfone, and tetramethylsulfone, N, N Aprotic solvents of amides such as methylacetamide, N, N-dimethylformamide, N, N′-diethyla-N-methyl-2-pyrrolidone, γ-butyllactone, hexamethylphosphoric triamide, or phosphorylamides And alkyl halides such as chloroform and methylene chloride, aromatic hydrocarbons such as benzene and toluene, phenols such as phenol and cresol, and ethers such as dimethyl ether, diethyl ether and p-cresol methyl ether. Can usually be used in combination as appropriate of two or more as needed using these solvents alone.

  The solvent used in the present invention may be a commercially available special grade or first grade, as it is, but these solvents are used after carrying out a dehydration purification treatment by a normal operation such as dry distillation. May be.

  Further, after use in the present invention, the volatile solvent may be recovered and purified before use. At this time, a certain kind of mixed solvent may be obtained after purification. Specifically, a solvent decomposition product or the like may be mixed in the recovered solvent, but it can be appropriately used in view of film properties.

  Polyimide is obtained by imidizing polyamic acid, and either a thermal curing method or a chemical curing method is used for imidization. The thermal cure method is a method in which an imidization reaction proceeds by heating alone without the action of a dehydrating ring-closing agent or the like. The chemical curing method is represented by a polyamic acid organic solvent solution, a chemical conversion agent typified by acid anhydrides such as acetic anhydride, and tertiary amines such as isoquinoline, β-picoline, and pyridine. This is a method of working with a catalyst. A thermal cure method may be used in combination with a chemical cure method. The reaction conditions for imidization can vary depending on the type of polyamic acid, the thickness of the film, the selection of a thermal curing method and / or a chemical curing method, and the like. Preferably, it is chemically cured from the viewpoints of film toughness, breaking strength, and productivity.

Next, the material used for the polyamic acid varnish according to the present invention will be described.
Tetracarboxylic acid anhydrides used in the synthesis of polyamic acid are pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic Acid dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenone Tetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, bis (3,4-dicarboxy) Phenyl) propane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, bis (2,3 -Dicarboxyfe ) Methane dianhydride, bis (3,4-dicarboxyphenyl) ethane dianhydride, oxydiphthalic dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, p-phenylenebis (trimerit Acid monoester acid anhydride), ethylene bis (trimellitic acid monoester acid anhydride), bisphenol A bis (trimellitic acid monoester acid anhydride) and the like, and these may be used alone or in any A mixture of proportions can be preferably used.

  Among these, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, p-phenylene It is preferable to use at least one selected from bis (trimellitic acid monoester anhydride) from the viewpoint of the mechanical strength of the resulting film.

  In general, tetracarboxylic dianhydride contains tetracarboxylic acid and tetracarboxylic acid monoanhydride, which are ring-opened products due to moisture, as impurities, but the tetracarboxylic dianhydride used in the present invention is a machine for the polyimide film obtained. From the viewpoint of mechanical strength and adhesiveness, it is preferable that the purity is high, and the purity is preferably an impurity amount of 1.5 wt% or less, more preferably an impurity amount of 1 wt% or less, most preferably an impurity amount of 0 .5 wt% or less.

  Examples of the diamine component used in the synthesis of the polyamic acid according to the present invention include 4,4′-diaminodiphenylpropane, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4. '-Diaminodiphenylmethane, benzidine, 3,3'-dichlorobenzidine, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 1,5-diaminonaphthalene, 4,4′-diaminodiphenyldiethylsilane, 4,4′-diaminodiphenylsilane, 4,4′-diaminodiphenylethyl Phosphine oxide, 4,4'-diamy Diphenyl N-methylamine, 4,4′-diaminodiphenyl N-phenylamine, 1,4-diaminobenzene (p-phenylenediamine), 1,3-diaminobenzene, 1,2-diaminobenzene, and the like It is preferable to use at least one selected from the viewpoint of the mechanical strength of the resulting film.

  Among these diamines, 4,4′-diaminodiphenyl ether and p-phenylenediamine are particularly preferable from the viewpoint that it is easy to design a polyimide film having a desired elastic modulus, and these are used in a molar ratio of 100: 0 to 0: Mixtures mixed at a ratio of 100, preferably 100: 0 to 10:90, can be preferably used.

  Further, when the imidization is performed by a chemical curing method, the chemical conversion agent added to the polyamic acid composition according to the present invention is, for example, an aliphatic acid anhydride, an aromatic acid anhydride, N, N′-dialkylcarbodiimide, Examples include lower aliphatic halides, halogenated lower aliphatic halides, halogenated lower fatty acid anhydrides, arylphosphonic acid dihalides, thionyl halides, or mixtures of two or more thereof, among which organic carboxylic acid anhydrides are preferred. Here, as the organic carboxylic acid anhydride, acetic anhydride, propionic anhydride, butyric anhydride, valeric anhydride, anhydrides mixed with each other, and aromatic monocarboxylic acids such as benzoic acid and naphthoic acid Mixtures with anhydrides such as carbonic acid, formic acid and aliphatic ketenes (ketene, and dimethylketene) anhydrides, and aliphatic anhydrides such as acetic anhydride, propionic anhydride, and anhydride, or 2 of them A mixture of two or more species can be mentioned, and among them, acetic anhydride can be preferably used. The amount of the chemical conversion agent can be used in a molar ratio of 1.0 to 8.0 times, more preferably 1.2 to 5.0 times, per mole of the amic acid of the polyamic acid varnish. If the amount of the chemical conversion agent is too small, the imidization rate tends to be smaller than the preferred range. If the amount is too large, decomposition occurs in the process of forming a partially cured and / or partially dried polyamic acid film. It progresses and the target mechanical properties are not expressed.

  Moreover, in order to perform imidation effectively, it is preferable to use a catalyst simultaneously with a chemical conversion agent. As the catalyst, aliphatic tertiary amine, aromatic tertiary amine, heterocyclic tertiary amine and the like are used. Among them, those selected from heterocyclic tertiary amines can be particularly preferably used. Specifically, quinoline, isoquinoline, β-picoline, pyridine and the like are preferably used. The amount of the catalyst may be 0.2 to 2.0 times, more preferably 0.3 to 1.5 times in molar ratio with respect to 1 mol of the amic acid of the polyamic acid varnish. If the amount is too small, the imidization rate tends to be smaller than the preferred range, and if the amount is too large, the curing becomes fast and it becomes difficult to cast on the support. Further, an imidization retarder such as acetylacetone may be used in combination as long as the physical properties are not affected.

It should be noted that the polyamic acid organic solvent solution or the chemical imidizing agent solution to be added thereto is optionally provided with an antioxidant, a light stabilizer, a flame retardant, an antistatic agent, a heat stabilizer, an ultraviolet absorber, or an inorganic Fillers or various reinforcing agents may be added.
After mixing the polyamic acid varnish obtained by the above method and the chemical imidizing agent, the polyimide film is continuously extruded from the slit die as a smooth thin film curtain and cast on an endless belt. A gel film having supportability is formed. This gel film is further heat-treated to obtain a polyimide film having the desired mechanical properties.

In the above method, the viscosity in the die of the resin solution composition in which the polyamic acid varnish and the chemical imidizing agent are mixed is preferably 450 poise or less, more preferably 300 poise or less, particularly preferably 50 to 300 poise. is there. When the viscosity is within this range, the variation in film thickness becomes remarkably high, and a polyimide film roll that does not generate deformation or wrinkles during storage cannot be obtained. Moreover, the bubble entrainment phenomenon is likely to occur, which is not preferable. In addition, when it is 50 poises or less, it is difficult to stably form a film in the present invention using the casting method using a die. This viscosity is a value measured with a B-type viscometer.
Moreover, it is preferable to control the clearance of the die opening for the purpose of suppressing variations in film thickness and preventing the polyimide film roll from being deformed or wrinkled during storage.
Next, the manufacturing process of the polyimide film concerning this invention is demonstrated.

  The production method for imidizing the polyamic acid, which is a polyimide precursor, and finally making a polyimide film product is a belt chamber or drum chamber which is cast-coated on an endless belt or casting drum to obtain a gel film, and a post-heating cure. It is divided into a tenter room.

  An example of the manufacturing process of the polyimide film concerning this invention is shown. First, in the process of the belt chamber, a process of extruding the polyimide precursor mixed by the mixer into a film shape by a T-die is performed. Form a film on top. The precursor formed into a film is dried while being moved by the rotation of a belt or a drum. In the belt chamber, the product produced by the reaction, mainly water, organic solvent, etc. evaporate.

  Heating means adjusts the ambient temperature and the rotation speed of the belt or drum in order to prevent the risk of ignition of flammable volatile components evaporated from the resin or to prevent the resin itself from igniting. For example, heating by hot air, hot air, radiant heat, belt heating or the like can be used.

  Through these steps, while drying the polyimide precursor film, after heating and drying to the extent that the film has self-supporting properties, it is peeled off from the endless belt or casting drum to obtain the gel film referred to in the present invention. .

  By the way, in the case of transporting a normal film through the above process, it is best to maintain the shape and surface state of the gel film and prevent difficulties on the surface such as peeling and wrinkling of the film. As an index for manufacturing without processing problems, the amount of residual volatiles is measured.

The amount of residual volatiles in the gel film is given by Equation 1.
(AB) × 100 / B... Formula 1
In Formula 1, A and B represent the following.
A: Weight of the gel film B: Calculated from the weight after heating the gel film at 450 ° C. for 20 minutes, and its volatile content is preferably in the range of 5 to 300%, more preferably 5 to 100%. It is in the range, more preferably in the range of 10-80%, most preferably in the range of 15-50%. It is preferable to use a gel film in this range, and if it is removed, the predetermined effect is hardly exhibited.

In addition, using infrared absorption spectrometry, the formula 2
(C / D) × 100 / (E / F)... Formula 2
In Formula 2, C, D, E, and F represent the following.
C: Absorption peak height of 1370 cm-1 of the gel film D: Absorption peak height of 1500 cm-1 of the gel film E: Absorption peak height of 1370 cm-1 of the polyimide film F: Absorption peak of 1500 cm-1 of the polyimide film The imidation ratio of the gel film calculated from the height is in the range of 50% or more, preferably 80% or more, more preferably 85% or more, and most preferably 90% or more. It is preferable to use a film in this range, and if it is removed, the predetermined effect is hardly exhibited.

  The gel film thus obtained is supplied to a tenter chamber where a heat treatment step is performed, and the ends are fixed and heat treatment is performed in the tenter chamber. For example, the tenter chamber is composed of a heating furnace and a slow cooling furnace, and the film moves in the tenter chamber by moving a pin sheet having a film fixed with pins by rotational driving of a pin conveyor. The gel film is further imidized by gradually heating in a heating furnace that performs thermal curing. In the heating furnace, the temperature is gradually raised from a temperature of usually about 200 ° C. to complete imidation into polyimide.

In order to completely remove residual volatiles and completely convert the polyamic acid to polyimide, it is preferable to heat stepwise and continuously according to a conventional method, and finally use a high temperature for a short time. Specifically, it is preferable to finally heat at a temperature of 400 to 650 ° C., more preferably at a temperature of 450 to 620 ° C. for 10 to 400 seconds. An aromatic polyamide-based polymer substantially composed of units selected from the group consisting of the following structural units.
In the heat treatment step, the completely imidized polyimide film is gradually cooled in a slow cooling furnace.
In addition, before supplying the gel film to the tenter chamber, a surface treatment solution may be applied to the gel film, or the gel film may be immersed in the surface treatment solution. The surface treatment solution to be treated is also a mechanical property of the film. And it will not be specifically limited if it is a grade which does not deteriorate an external appearance remarkably.
In addition, the polyimide film obtained above can be subjected to a known physical surface treatment such as a corona discharge treatment or a plasma discharge treatment, or a chemical surface treatment such as a primer treatment, thereby imparting better properties.
In addition, the above film is subjected to a heat treatment of 200 ° C. or more and 500 ° C. or less, if necessary, and then wound on a core to form a film roll. Here, the heat treatment can be performed under tension, under a constant length, or in a relaxed state, and can be performed in two or more stages by combining these.
When winding the film obtained above in a roll shape, it is also preferable to wind the film while meandering in order to reduce the occurrence of uneven thickness and so-called gauge bands on the roll due to uneven thickness in the width direction of the film. This is an embodiment. When winding, it is also preferable to cut off the ears of the film and align the end face of the roll, or to wind the film roll by a method called touch winding while bringing a guide roll made of metal or resin into contact with the film roll.

  In carrying out the present invention, the material of the core is not particularly limited, and is a combination of paper, plastic such as vinyl chloride, or a combination of glass fiber and epoxy resin, paper and phenol resin, carbon fiber and epoxy resin, etc. The effects of the present invention are conventionally used, such as fiber reinforced plastics (FRP), metals such as stainless steel, paper cores impregnated with resin, or those having a resin layer formed on the surface thereof. It is used as long as it is not damaged.

  The outer diameter of the core around which the polyimide film is wound is preferably 70 to 250 mm, more preferably 150 to 250 mm. When the outer diameter of the core is small, the radius of curvature at the winding core portion becomes small, and curling is likely to occur, and the number of overlapping films at the time of film roll increases, so that deformation and wrinkles tend to occur. Conversely, when the outer diameter of the core is increased, the outer diameter of the film roll also increases, which may be inconvenient during transportation and storage.

  In practicing the present invention, the linear expansion coefficient of the polyimide film is preferably 10 to 20 ppm, more preferably 12 to 20 ppm. When the linear expansion coefficient is larger than this, deformation due to expansion / contraction due to temperature changes during storage or transportation is large, which causes deformation and wrinkles. When the linear expansion coefficient is less than this, the difference in expansion from the copper foil is large when laminated with the copper foil, which also causes deformation and wrinkles.

  In carrying out the present invention, the effect is manifested when the outer diameter of the polyimide film roll is increased. In particular, the effect is conspicuous when the number of windings is 7000 or more, and further 7500 or more.

  Moreover, when implementing this invention, when the width | variety of a polyimide film roll becomes large, the effect is expressed. In particular, when the width is 250 mm or more, and further 500 mm or more, the effect is remarkable.

The embodiments and effects of the present invention will be described below with reference to examples, but the present invention is not limited thereto. In the present invention, the elastic modulus and linear expansion coefficient of the film were evaluated by the following methods.
"Elastic modulus of film"
The elastic modulus of the film was evaluated based on JIS C-2318.
"Linear expansion coefficient"
As the linear expansion coefficient, a thermomechanical tester TMA-8140 manufactured by Rigaku Denki was used. First, the temperature was raised from room temperature to 400 ° C. under conditions of 10 ° C./min, and then cooled to room temperature. The temperature was increased again under the same conditions, and the linear expansion coefficient in the temperature range of 100 to 200 ° C. was determined.

<Example 1>
Polyamic acid DMF solution polymerized using 4,4′-diaminodiphenyl ether and p-phenylenediamine mixed at a molar ratio of 75:25 and pyromellitic dianhydride (solid content concentration 20%, 20 50 parts by weight of an imidizing agent having a ratio of 200 parts by weight of acetic anhydride, 100 parts by weight of isoquinoline and 190 parts by weight of DMF is mixed with 100 parts by weight of viscosity at 2800 poise at ℃. It was extruded and cast onto a stainless steel endless belt. The gel was heated on this endless belt at 110 ° C. for 2 minutes to obtain a self-supporting gel film. This gel film had a residual volatile content of 30% by weight and an imidation ratio of 85%. This gel film was heated at 250 ° C., 400 ° C., and 550 ° C. for 20 seconds each, and a polyimide film having a thickness of 25 μm, an elastic modulus of 4.1 GPa, a linear expansion coefficient of 18 ppm, and a width of 520 mm was applied to a plastic core having an outer diameter of 170 mm. A polyimide film roll was obtained by winding 7500 rolls with a tension of 35 N and a touch pressure of 70 N. In the polyimide film roll thus obtained, immediately after winding, after storage for 1 week, neither deformation nor wrinkle of the roll was observed, and no wrinkles or molds were found on the single leaf of the film even when it was unwound from the roll. .

<Example 2>
Polyamic acid DMF solution polymerized using 4,4′-diaminodiphenyl ether and p-phenylenediamine mixed at a molar ratio of 75:25 and pyromellitic dianhydride (solid content concentration 20%, 20 50 parts by weight of an imidizing agent having a ratio of 200 parts by weight of acetic anhydride, 100 parts by weight of isoquinoline and 190 parts by weight of DMF is mixed with 100 parts by weight of viscosity at 2800 poise at ℃. It was extruded and cast onto a stainless steel endless belt. The gel was heated on this endless belt at 110 ° C. for 2 minutes to obtain a self-supporting gel film. This gel film had a residual volatile content of 30% by weight and an imidation ratio of 85%. A plastic film obtained by heating the gel film at 250 ° C., 400 ° C., and 550 ° C. for 20 seconds each and having a thickness of 12.5 μm, an elastic modulus of 4.1 GPa, a linear expansion coefficient of 18 ppm, and a width of 520 mm is a plastic having an outer diameter of 170 mm. The core was wound with 7500 rolls with a tension of 30 N and a touch pressure of 70 N to obtain a polyimide film roll. In the polyimide film roll thus obtained, immediately after winding, after storage for 1 week, neither deformation nor wrinkle of the roll was observed, and no wrinkles or molds were found on the single leaf of the film even when it was unwound from the roll. .

<Example 3>
Polyamic acid DMF solution polymerized using diamine mixed with 4,4′-diaminodiphenyl ether and p-phenylenediamine in a molar ratio of 85:15 and pyromellitic dianhydride (solid content concentration 20%, 20 50 parts by weight of an imidizing agent composed of 200 parts by weight of acetic anhydride, 100 parts by weight of isoquinoline and 190 parts by weight of DMF with respect to 100 parts by weight of 100 parts by weight of viscosity at ℃. It was extruded and cast onto a stainless steel endless belt. The gel was heated on this endless belt at 110 ° C. for 2 minutes to obtain a self-supporting gel film. This gel film had a residual volatile content of 30% by weight and an imidation ratio of 85%. This gel film was heated at 250 ° C., 400 ° C., and 550 ° C. for 20 seconds each, and a polyimide film having a thickness of 25 μm, an elastic modulus of 3.5 GPa, a linear expansion coefficient of 20 ppm, and a width of 520 mm was applied to a plastic core having an outer diameter of 170 mm. 7500 rolls were wound with a tension of 35 N and a touch pressure of 70 N to obtain a polyimide film roll. In the polyimide film roll thus obtained, immediately after winding, after storage for 1 week, neither deformation nor wrinkle of the roll was observed, and no wrinkles or molds were found on the single leaf of the film even when it was unwound from the roll. .

<Example 4>
Polyamic acid DMF solution polymerized using diamine mixed with 4,4′-diaminodiphenyl ether and p-phenylenediamine in a molar ratio of 70:30 and pyromellitic dianhydride (solid content concentration 20%, 20 50 parts by weight of an imidizing agent composed of 200 parts by weight of acetic anhydride, 100 parts by weight of isoquinoline and 190 parts by weight of DMF with respect to 100 parts by weight of 100 parts by weight of viscosity at ℃. It was extruded and cast onto a stainless steel endless belt. The gel was heated on this endless belt at 110 ° C. for 2 minutes to obtain a self-supporting gel film. This gel film had a residual volatile content of 30% by weight and an imidation ratio of 85%. This gel film was heated at 250 ° C., 400 ° C. and 550 ° C. for 20 seconds each, and a polyimide film having a thickness of 25 μm, an elastic modulus of 4.5 GPa, a linear expansion coefficient of 10 ppm and a width of 520 mm was applied to a plastic core having an outer diameter of 170 mm. 7500 rolls were wound with a tension of 35 N and a touch pressure of 70 N to obtain a polyimide film roll having an outer diameter of 350 mm. In the polyimide film roll thus obtained, immediately after winding, after storage for 1 week, neither deformation nor wrinkle of the roll was observed, and no wrinkles or molds were found on the single leaf of the film even when it was unwound from the roll. .

<Comparative Example 1>
200 parts by weight of acetic anhydride per 100 parts by weight of polyamic acid DMF solution (solid content 20%, viscosity 2800 poise at 20 ° C.) polymerized using 4,4′-diaminodiphenyl ether and pyromellitic dianhydride 50 parts by weight of an imidizing agent having a ratio of 100 parts by weight of isoquinoline and 190 parts by weight of DMF, rapidly stirred with a mixer, extruded from a T-die, and cast onto a stainless endless belt. The gel was heated on this endless belt at 110 ° C. for 2 minutes to obtain a self-supporting gel film. This gel film had a residual volatile content of 30% by weight and an imidation ratio of 85%. This gel film was heated at 250 ° C., 400 ° C., and 550 ° C. for 20 seconds each, and a polyimide film having a thickness of 25 μm, an elastic modulus of 3.3 GPa, a linear expansion coefficient of 30 ppm, and a width of 520 mm was applied to a plastic core having an outer diameter of 170 mm. A polyimide film roll was obtained by 7000 rolls with a tension of 35 N and a touch pressure of 70 N. Immediately after winding of the polyimide film roll thus obtained, no deformation or wrinkle of the roll was observed, but after storage for 1 week, a film having a length of 200 mm and a width of 3 mm was raised at the center of the roll surface. One wrinkle was observed. Moreover, it was confirmed that the wrinkle type | mold was attached to the film single leaf when letting out from a roll.

<Comparative example 2>
200 parts by weight of acetic anhydride per 100 parts by weight of polyamic acid DMF solution (solid content 20%, viscosity 2800 poise at 20 ° C.) polymerized using 4,4′-diaminodiphenyl ether and pyromellitic dianhydride 50 parts by weight of an imidizing agent having a ratio of 100 parts by weight of isoquinoline and 190 parts by weight of DMF, rapidly stirred with a mixer, extruded from a T-die, and cast onto a stainless endless belt. The gel was heated on this endless belt at 110 ° C. for 2 minutes to obtain a self-supporting gel film. This gel film had a residual volatile content of 30% by weight and an imidation ratio of 85%. A plastic film obtained by heating this gel film at 250 ° C., 400 ° C., and 550 ° C. for 20 seconds each and having a thickness of 12.5 μm, an elastic modulus of 3.3 GPa, a linear expansion coefficient of 30 ppm, and a width of 520 mm is a plastic having an outer diameter of 170 mm. The core was wound with 7000 rolls with a tension of 30 N and a touch pressure of 70 N to obtain a polyimide film roll. Immediately after winding of the polyimide film roll thus obtained, no deformation or wrinkle of the roll was observed, but after storage for 1 week, a film having a length of 200 mm and a width of 3 mm was raised at the center of the roll surface. One wrinkle was observed. Moreover, it was confirmed that the wrinkle type | mold was attached to the film single leaf when letting out from a roll.

<Reference Example 1>
200 parts by weight of acetic anhydride per 100 parts by weight of polyamic acid DMF solution (solid content 20%, viscosity 2800 poise at 20 ° C.) polymerized using 4,4′-diaminodiphenyl ether and pyromellitic dianhydride 50 parts by weight of an imidizing agent having a ratio of 100 parts by weight of isoquinoline and 190 parts by weight of DMF, rapidly stirred with a mixer, extruded from a T-die, and cast onto a stainless endless belt. The gel was heated on this endless belt at 110 ° C. for 2 minutes to obtain a self-supporting gel film. This gel film had a residual volatile content of 30% by weight and an imidation ratio of 85%. A plastic film obtained by heating this gel film at 250 ° C., 400 ° C., and 550 ° C. for 20 seconds each with a thickness of 37.5 μm, an elastic modulus of 3.3 GPa, a linear expansion coefficient of 30 ppm, and a width of 520 mm is a plastic having an outer diameter of 170 mm. The core was wound with 7500 rolls with a tension of 70 N and a touch pressure of 70 N to obtain a polyimide film roll. In the polyimide film roll thus obtained, immediately after winding, after storage for 1 week, neither deformation nor wrinkle of the roll was observed, and no wrinkles or molds were found on the single leaf of the film even when it was unwound from the roll. .

Claims (4)

A roll-shaped polyimide film obtained by winding a polyimide film on a winding core, the number of windings is 7000 or more, and the polyimide film has a thickness of 1 to 30 μm, and an elastic modulus of the film is 3. A roll-shaped polyimide film characterized by being 5 GPa to 4.5 GPa. The roll-like polyimide film according to claim 1, wherein the polyimide film has a linear expansion coefficient of 10 to 20 ppm. The roll-shaped polyimide film according to claim 1 or 2, wherein a width of the polyimide film is 250 mm or more. The roll-shaped polyimide film according to any one of claims 1 to 3, wherein a diameter of the core is 70 mm or more and 250 mm or less.