JP2009013245A - Polyimide film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an extremely thin and long film with less uneven thickness of a polyimide film excellent in heat resistance and mechanical properties. <P>SOLUTION: The polyimide film has a thickness of not more than 7 μm and thickness unevenness of not more than 20%. For example, a polyimide precursor film or a polyimide film which is slit into a small width and separately prepared from a film to be processed is superposed on both side ends of the film to be processed, and the side ends of the film are held together with the slit film by sticking pins or pinching with clips, and the polyamic acid is imidized so as to prevent the film from fracturing into a long hole form in the longitudinal or width direction to the film and from aggravating the uneven thickness. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ultra-thin polyimide film, in particular, a polyimide film having a thickness of 7 μm or less, which is a final heat treatment at the time of manufacturing the polyimide precursor film to obtain a polyimide film by high-temperature heat treatment. Dimensional stability with a very thin and small thickness variation obtained by devising film gripping at both ends in the width direction of the film in the tenter type (film transport) processing section. The present invention relates to an industrially produced polyimide film having excellent properties.

When a polyimide film is produced industrially, a polyimide precursor film (also referred to as a green film) in which a part of the solvent remains is imidized at a high temperature. In this case, drying and heat treatment are carried out by heating while conveying the polyimide precursor film, but a film having a small amount of these solvents generally shrinks as it is dried. In such film transport / drying / heat treatment, as an apparatus for manufacturing a film by transporting the film in the stretched width direction by holding both ends in the width direction of the film with a large number of pins and clips, A film tenter type conveying device called a so-called tenter is known (see Patent Document 1).
In addition, it is also known to use a tenter type conveying device for manufacturing a polyimide film (see Patent Document 2).
The film conveying apparatus has been well known for a long time to be used for drying so as not to cause wrinkles in the drying process after dyeing the cloth. In addition to drying the cloth, it is also used for drying an undried plastic film by a solvent casting method while transporting it in the drying step. By using the film conveying apparatus, it is possible to suppress shrinkage of the film in the width direction due to heat during drying and heat treatment, and to prevent wrinkles due to shrinkage from occurring in the film after drying and heat treatment.
Film shrinkage occurs not only in the width direction of the film but in all directions, but the film transport direction is said to have a restraining effect on the shrinkage because the transport tension is acting, but the film thickness is extremely When the thickness is reduced, damage to the gripping portion due to shrinkage or the like also increases in the film transport direction. Thus, when the undried film is heat-treated, it is transported using a film tenter-type transport device, thereby ensuring the strength and flatness necessary for the dried and heat-treated film.

Among the film tenter type conveying devices, the tenter type conveying device for the film that holds the film stretched in the width direction by biting a large number of pins along both side edges of the film was arranged in parallel A large number of pins are arranged on a pin sheet supported in a row by a pair of moving chains. This film tenter type transport device is simpler in structure than the film transport device such as the clip, or can be structured to reverse the transport conveyor path in the drying chamber. On the other hand, since the fine pieces of the film generate dust when the pins are bitten into the film, it is necessary to reduce the number of pins as much as possible. Moreover, when the shrinkage force of the film becomes large, there are problems such as the holes that have pinned the film surface break into long holes in the width direction of the film.
For these improvements, a method in which a film having a large tear strength is additionally used for reinforcement in the grip portion by the pin of the film has been proposed (see Patent Document 3), but the technique has a low tear strength. When processing a polymer resin film having a thickness of 50 to 150 μm with a film end fixed type tenter, particularly when stretched in the width direction, the sheet gripping portion at the film end has a higher tear strength than the film. In addition, the method is a method of stably tentering a polymer resin film having a low tear strength, in which the film and the reinforcing film that can be attached are overlapped and attached, and the reinforcing film is subjected to a force treatment. If the film to be processed is a polyimide film, not an ultra-thin polyimide film, it has such a strength that it does not need to be reinforced by the gripping part as long as it is such a thickness. The imidization is a high temperature treatment reaching 500 ° C.

Furthermore, a tenter type conveying device has also been proposed in which the innermost pin density is increased and the outer pin arrangement density is further reduced in the arrangement of pins that can be placed on both ends of the web when the web is conveyed (patent). Reference 4). Even in these proposals for improvement, there is nothing to consider the arrangement in the conveying direction of the pins, particularly the arrangement of the pins between the pin sheets. There was a problem in the production of films that are likely to occur.
Conventional tenter type transport devices for films tend to cause production loss due to problems such as breakage in the shape of a long hole in the width direction of the film at the hole where the pin is entrapped, and generation of wrinkles. At the same time, the production efficiency was lowered, and it was not satisfactory for users.
In particular, when an extremely thin polyimide film is manufactured by a tenter type conveying method, the above-mentioned problem becomes remarkable and cannot be overcome by the conventional proposed technique. Furthermore, in an ultra-thin film having a thickness of 7.5 μm or less, such as a polyimide film, there is a problem that unevenness in the thickness becomes significant.
Japanese Examined Patent Publication No. 39-029211 JP 09-188863 A Japanese Patent Laid-Open No. 11-254521 JP 09-073315 A

  The present invention is excellent in flatness and homogeneity suitable as a base material or insulating material for electronic parts, and also has an extremely thin polyimide film among the polyimide films excellent in heat resistance that does not change even when subjected to high temperature treatment. Efficiently eliminates the problem of poor quality due to breaking at both ends of the film in the width direction and longitudinal direction of the film when gripping at the both ends of the film by the transport method and manufacturing, An object of the present invention is to provide a polyimide film having little thickness unevenness and excellent in dimensional stability.

That is, this invention is based on the following structures.
1. A polyimide film having a thickness of 7 μm or less obtained by casting, drying and heat-treating a polyamic acid solution obtained by reacting an aromatic tetracarboxylic acid and an aromatic diamine, and having a width direction and a longitudinal direction of the film A polyimide film characterized by having a thickness unevenness of 20% or less.
2. 1. The polyimide film is a polyimide film roll having a width of 500 mm or more and a length of 100 m or more. Polyimide film.
3. 1. The aromatic diamine is an aromatic diamine having a benzoxazole structure. Or 2. Any polyimide film.
4). 1. Linear expansion coefficient is 5 ppm / ° C. or less. ~ 3. Any polyimide film.

  The polyimide film of the present invention has a narrow width prepared separately from the film to be processed and manufactured, for example, at both end portions of the film in a tenter type processing unit (conveying device) when manufacturing a polyimide film having a thickness of 7 μm or less. Even when the polyimide precursor film and / or the polyimide film that have been slit are overlapped and stabbed together with the pin provided on the pin sheet or held with a clip, even at high temperatures reaching 500 ° C. such as when imidizing polyamic acid It can withstand the full effect of the reinforcement and breaks into a long hole in the longitudinal and width directions of the film, eliminating the problems of low yield and poor quality. The ultra-thin polyimide with excellent dimensional stability that can eliminate the quality problems in the manufactured ultra-thin polyimide film. This ultra-thin polyimide film has excellent stability at high temperatures, especially dimensional stability, and has little thickness unevenness, so it can be used for manufacturing electronic components at high temperatures and when electronic components are used at high temperatures. There is no deviation in dimensions, and it can contribute to lightness and thinness of electronic parts.

The polyimide film of the present invention is generally called aromatic tetracarboxylic acids (anhydride, acid, and amide-bonded derivatives are collectively referred to as classes hereinafter) and aromatic diamines (amines and amide-bonded derivatives are collectively named). It is a polyimide film obtained by a method in which a polyamic acid solution obtained by reacting with the above is reacted, and dried to form a film by heat treatment (imidization). Examples of the solvent used in these solutions include N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide and the like.
The method for producing a polyimide film of the present invention is most preferably applied particularly when a casting film forming method using an N-methyl-2-pyrrolidone solution or N, N-dimethylacetamide solution of polyamic acid, which is a polyimide precursor, is used. obtain.
The reaction between an aromatic diamine for obtaining a polyimide film, which can be preferably applied to the present invention, and an aromatic tetracarboxylic acid is carried out by reacting an aromatic diamine and an aromatic tetracarboxylic acid (anhydride) in a solvent. (Ring-opening) A solution of polyamic acid which is a polyimide precursor is obtained by polyaddition reaction, and then a polyimide precursor film (also referred to as a green film) is formed from the polyamic acid solution, followed by drying and imidization ( It is manufactured by heat treatment or dehydration condensation.

The polyimide film in the present invention is not particularly limited, and aromatic tetracarboxylic acids (an anhydride, an acid, and an amide bond derivative are collectively referred to as a class hereinafter) and aromatic diamines (amine, and It is an aromatic polyimide obtained by reacting amide bond derivatives generically, referred to hereinafter as the same). A combination of the following aromatic diamines and aromatic tetracarboxylic acids (anhydrides) is a preferred example.
A. A combination of an aromatic diamine having a benzoxazol skeleton and an aromatic tetracarboxylic acid.
B. A combination of an aromatic diamine having a diaminodiphenyl ether skeleton and an aromatic tetracarboxylic acid having a pyromellitic acid skeleton.
C. A combination of an aromatic diamine having a phenylenediamine skeleton and an aromatic tetracarboxylic acid having a biphenyltetracarboxylic acid skeleton.
D. A combination of one or more of the above ABCs.

Examples of the aromatic diamine having a diaminodiphenyl ether skeleton in the present invention include 4,4′-diaminodiphenyl ether (DADE), 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, and derivatives thereof. Examples of the aromatic diamine having a phenylenediamine skeleton in the invention include p-phenylenediamine, m-phenylenediamine, o-phenylenediamine and derivatives thereof. Examples of the diamine having a benzoxazol skeleton in the present invention include the following. Although the diamine shown by a specific example is mentioned, It is preferable to use these diamines 70 mol% or more of all the diamines, More preferably, 80 mol% or more.
Specific examples of aromatic diamines having a benzoxazole structure include the following.

Among these, amino (aminophenyl) benzoxazole isomers are preferable from the viewpoint of ease of synthesis. Here, “each isomer” refers to each isomer in which two amino groups of amino (aminophenyl) benzoxazole are determined according to the coordination position (eg, the above “formula 1” to “formula 4”). Each compound described in the above.
Moreover, as aromatic diamines other than the above, the following aromatic diamines can be used if they are less than 30 mol%, more preferably less than 20 mol% of all amines in the present invention.

  4,4′-bis (3-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (3-amino Phenoxy) phenyl] sulfone, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] -1,1,1,3,3 , 3-hexafluoropropane, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl sulfide, 3,3′-di Mino diphenyl sulfoxide, 3,4'-diaminodiphenyl sulfoxide, 4,4'-diaminodiphenyl sulfoxide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone,

3,3′-diaminobenzophenone, 3,4′-diaminobenzophenone, 4,4′-diaminobenzophenone, 3,3′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, bis [ 4- (4-aminophenoxy) phenyl] methane, 1,1-bis [4- (4-aminophenoxy) phenyl] ethane, 1,2-bis [4- (4-aminophenoxy) phenyl] ethane, 1, 1-bis [4- (4-aminophenoxy) phenyl] propane, 1,2-bis [4- (4-aminophenoxy) phenyl] propane, 1,3-bis [4- (4-aminophenoxy) phenyl] Propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 1,1-bis [4- (4-aminopheno) Cis) phenyl] butane, 1,3-bis [4- (4-aminophenoxy) phenyl] butane, 1,4-bis [4- (4-aminophenoxy) phenyl] butane, 2,2-bis [4- (4-Aminophenoxy) phenyl] butane, 2,3-bis [4- (4-aminophenoxy) phenyl] butane, 2- [4- (4-aminophenoxy) phenyl] -2- [4- (4- Aminophenoxy) -3-methylphenyl] propane, 2,2-bis [4- (4-aminophenoxy) -3-methylphenyl] propane, 2- [4- (4-aminophenoxy) phenyl] -2- [ 4- (4-aminophenoxy) -3,5-dimethylphenyl] propane, 2,2-bis [4- (4-aminophenoxy) -3,5-dimethylphenyl] propane, 2,2-bis [4- 4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane,

4-bis (3-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy)
Benzene, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, bis [4- (4-aminophenoxy) phenyl] ketone, bis [4- (4- Aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfoxide, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, 1,3-bis [4- (4-aminophenoxy) benzoyl] benzene,

1,3-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,4-bis [4- (3-aminophenoxy) benzoyl] benzene, 4,4′-bis (3-aminophenoxy) benzoyl] Benzene, 1,1-bis [4- (3-aminophenoxy) phenyl] propane, 1,3-bis [4- (3-aminophenoxy) phenyl] propane, 3,4'-diaminodiphenyl sulfide, 2,2 -Bis [3- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, bis [4- (3-aminophenoxy) phenyl] methane, 1,1-bis [ 4- (3-aminophenoxy) phenyl] ethane, 1,2-bis [4- (3-aminophenoxy) phenyl] ethane, bis [4- (3-aminophenoxy) phenyl Sulfoxides, 4,4'-bis [3- (4-aminophenoxy) benzoyl] diphenylether, 4,4'-bis [3- (3-aminophenoxy) benzoyl] diphenylether,

4,4′-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] benzophenone, 4,4′-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] diphenylsulfone Bis [4- {4- (4-aminophenoxy) phenoxy} phenyl] sulfone, 1,4-bis [4- (4-aminophenoxy) phenoxy-α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-aminophenoxy) phenoxy-α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-amino-6-trifluoromethylphenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-amino-6-fluorophenoxy) -α, α-dimethylbenzyl] benzene,

1,3-bis [4- (4-amino-6-methylphenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-amino-6-cyanophenoxy) -α, α -Dimethylbenzyl] benzene, 3,3'-diamino-4,4'-diphenoxybenzophenone, 4,4'-diamino-5,5'-diphenoxybenzophenone, 3,4'-diamino-4,5'- Diphenoxybenzophenone, 3,3′-diamino-4-phenoxybenzophenone, 4,4′-diamino-5-phenoxybenzophenone, 3,4′-diamino-4-phenoxybenzophenone, 3,4′-diamino-5′- Phenoxybenzophenone, 3,3′-diamino-4,4′-dibiphenoxybenzophenone, 4,4′-diamino-5,5′-dibiphenoxyben Phenone, 3,4′-diamino-4,5′-dibiphenoxybenzophenone, 3,3′-diamino-4-biphenoxybenzophenone, 4,4′-diamino-5-biphenoxybenzophenone, 3,4′-diamino -4-biphenoxybenzophenone, 3,4'-diamino-5'-biphenoxybenzophenone,

1,3-bis (3-amino-4-phenoxybenzoyl) benzene, 1,4-bis (3-amino-4-phenoxybenzoyl) benzene, 1,3-bis (4-amino-5-phenoxybenzoyl) benzene 1,4-bis (4-amino-5-phenoxybenzoyl) benzene, 1,3-bis (3-amino-4-biphenoxybenzoyl) benzene, 1,4-bis (3-amino-4-biphenoxy) Benzoyl) benzene, 1,3-bis (4-amino-5-biphenoxybenzoyl) benzene, 1,4-bis (4-amino-5-biphenoxybenzoyl) benzene, 2,6-bis [4- (4 -Amino-α, α-dimethylbenzyl) phenoxy] benzonitrile, aromatic diamines having a benzoxazole structure and aromatic rings of the above aromatic diamines Carbon in which some or all of the above hydrogen atoms are halogen atoms, alkyl groups or alkoxy groups having 1 to 3 carbon atoms, cyano groups, or some or all of the hydrogen atoms of alkyl groups or alkoxy groups are substituted with halogen atoms Examples thereof include aromatic diamines substituted with a halogenated alkyl group or an alkoxy group of 1 to 3.
These aromatic diamines may be used alone or in combination of two or more.

  The aromatic tetracarboxylic acids used in the present invention are preferably aromatic tetracarboxylic anhydrides, and the following chemical formulas 14 and 15 are preferably used in an amount of 70 mol% or more of the total acid component, and 80 mol%. More preferably used. Specific examples of those that can be used in addition to these include the following, but these are used in an amount of less than 30 mol%, more preferably less than 20 mol% of the total acid component.

これらの芳香族テトラカルボン酸無水物類は単独でも二種以上を用いることも可能である。

These aromatic tetracarboxylic anhydrides can be used alone or in combination of two or more.

  In the present invention, the non-aromatic tetracarboxylic dianhydrides exemplified below may be used alone or in combination of two or more if less than 30 mol%, preferably less than 10 mol% of the total tetracarboxylic acid. I do not care. Examples of the non-aromatic tetracarboxylic dianhydrides used include butane-1,2,3,4-tetracarboxylic dianhydride and pentane-1,2,4,5-tetracarboxylic dianhydride. , Cyclobutanetetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, cyclohex-1-ene- 2,3,5,6-tetracarboxylic dianhydride, 3-ethylcyclohex-1-ene-3- (1,2), 5,6-tetracarboxylic dianhydride, 1-methyl-3- Ethylcyclohexane-3- (1,2), 5,6-tetracarboxylic dianhydride, 1-methyl-3-ethylcyclohex-1-ene-3- (1,2), 5,6-tetracarboxylic Acid dianhydride, 1-ethylsic Hexane-1- (1,2), 3,4-tetracarboxylic dianhydride, 1-propylcyclohexane-1- (2,3), 3,4-tetracarboxylic dianhydride, 1,3-di Propylcyclohexane-1- (2,3), 3- (2,3) -tetracarboxylic dianhydride, dicyclohexyl-3,4,3 ′, 4′-tetracarboxylic dianhydride, bicyclo [2.2 .1] Heptane-2,3,5,6-tetracarboxylic dianhydride, 1-propylcyclohexane-1- (2,3), 3,4-tetracarboxylic dianhydride, 1,3-dipropyl Cyclohexane-1- (2,3), 3- (2,3) -tetracarboxylic dianhydride, dicyclohexyl-3,4,3 ′, 4′-tetracarboxylic dianhydride, bicyclo [2.2. 1] Heptane-2,3,5,6-tetracarboxylic Dianhydride, bicyclo [2.2.2] octane-2,3,5,6-tetracarboxylic dianhydride, bicyclo [2.2.2] oct-7-ene-2,3,5,6 -Tetracarboxylic dianhydrides and the like. These non-aromatic tetracarboxylic dianhydrides can be used alone or in combination of two or more.

  The solvent used when polymerizing aromatic diamines and aromatic tetracarboxylic acid anhydrides to obtain polyamic acid is particularly limited as long as it dissolves both the raw material monomer and the polyamic acid to be produced. Although not preferred, polar organic solvents are preferred, such as N-methyl-2-pyrrolidone, N-acetyl-2-pyrrolidone, N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide Hexamethylphosphoric amide, ethyl cellosolve acetate, diethylene glycol dimethyl ether, sulfolane, halogenated phenols and the like, among which N-methyl-2-pyrrolidone and N, N-dimethylacetamide are preferably applied. These solvents can be used alone or in combination. The amount of the solvent used may be an amount sufficient to dissolve the monomer as a raw material. As a specific amount used, the mass of the monomer in the solution in which the monomer is dissolved is usually 5 to 40% by mass, The amount is preferably 10 to 20% by mass.

Conventionally known conditions may be applied for the polymerization reaction for obtaining the polyamic acid (hereinafter also simply referred to as “polymerization reaction”). As a specific example, in a temperature range of 0 to 80 ° C., 10 Stirring and / or mixing continuously for 30 minutes. If necessary, the polymerization reaction may be divided or the temperature may be increased or decreased. In this case, the order of adding both monomers is not particularly limited, but it is preferable to add aromatic tetracarboxylic acid anhydrides to the solution of aromatic diamines. The mass of the polyamic acid in the polyamic acid solution obtained by the polymerization reaction is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, and the viscosity of the solution is measured with a Brookfield viscometer (25 ° C.). From the viewpoint of the stability of liquid feeding, it is preferably 10 to 2000 Pa · s, and more preferably 100 to 1000 Pa · s. The reduced viscosity (ηsp / C) of the polyamic acid in the present invention is not particularly limited, but is preferably 1.5 dl / g or more, more preferably 2.0 dl / g or more, still more preferably 2.5 dl / g or more. preferable. Moreover, you may perform superposition | polymerization by adding a small amount of terminal blockers to aromatic diamines before a polymerization reaction. Examples of the end capping agent include compounds having a carbon-carbon double bond such as maleic anhydride. The amount of maleic anhydride used is preferably 0.001 to 1.0 mol per mol of aromatic diamine.
Vacuum degassing during the polymerization reaction is effective in producing a good quality polyamic acid solution. Furthermore, in order to obtain the polyimide film of the present invention, it is possible to remove bubbles and dissolved gas in the solution in advance by treatment such as decompression when casting and applying a polyamic acid solution described below onto the support. This is an effective process.

  The support on which the polyamic acid solution is cast (applied) only needs to have smoothness and rigidity sufficient to form the polyamic acid solution into a film, and the surface is made of metal, plastic, glass, porcelain, etc. A certain drum or a belt-like rotating body may be used. A method using a polyimide film having moderate rigidity and high smoothness is also a preferred embodiment. Among them, the surface of the support is preferably a metal, more preferably stainless steel that does not rust and has excellent corrosion resistance. The surface of the support may be plated with metal such as Cr, Ni, or Sn. The surface of the support can be mirror-finished or processed into a satin finish as required. The air volume and temperature in drying may be appropriately selected and adopted depending on the difference in the support, and the polyamic acid solution can be applied to the support by casting from a nozzle with a slit, extrusion by an extruder, squeegee coating, reverse coating, die Including, but not limited to, coating, applicator coating, wire bar coating and the like, conventionally known solution application means can be used as appropriate.

In the present invention, a method for obtaining a polyimide film having a thickness of 7 μm or less and a thickness unevenness of 20% or less is not particularly limited. However, when casting a polyamic acid solution on a support, By using a high backup roll, the thickness unevenness at the time of coating can be reduced, and in particular, the thickness unevenness in the MD direction (also referred to as the machine direction or the flow direction) can be reduced.
The roundness of the backup roll is expressed by the amount of eccentricity of the roll described below, and the amount of eccentricity (μm) is preferably 3 or less, and particularly preferably 2 or less.

In these methods, a method of controlling the eccentricity of the backup roll of the coater to 3 (μm) or less, preferably 2 (μm) or less is preferable. The measurement of the eccentric amount of the backup roll is a value obtained by abutting a dial gauge on the end surface of the backup roll and measuring the displacement amount of the gauge at the left end surface, the right end surface, and the center portion of the backup roll.
More specifically, the dial gauge uses a capacitance type dial gauge (manufactured by Ozaki Seisakusho, trade name PEACOCK, model DG-205, measurement range 25 mm, minimum display amount 0.001 mm, accuracy 0.003 mm).
The dial gauge is fixed to the roll frame with a magnetic chuck. Eccentricity measurement is repeated 6 times for each portion divided into 8 in the circumferential direction. The measurement should be performed in an environment where temperature and humidity are stable and there is no vibration. The roll driving speed is 1 m / min.
Measurement is performed both with and without film. When there is a film, the film tension is about 100N.

Control of the eccentric amount of the backup roll is performed by removing the plating of the backup roll when the eccentric amount is large, and performing the control of the eccentric amount through at least the processes of cutting and polishing, and polishing the backup roll when the eccentric amount is small. Perform machining to control the amount of eccentricity.
The material of the backup roll is preferably carbon steel for mechanical structure (STKM, S45C).
Hard chrome plating is good for the surface treatment of the backup roll. The diameter of the roll is desirably about 200 to 400 mm. As the bearing, it is preferable to use a bearing having a dimensional accuracy and a rotational accuracy of the grade 4 or higher of the accuracy grade specified in JIS B1514.

In the imidization step, a ring closure (imidation) catalyst or a polyamic acid solution that does not contain a dehydrating agent is used for heat treatment to advance the imidization reaction (so-called thermal ring closure method) or a ring closure catalyst in the polyamic acid solution. And a chemical ring closing method in which an imidization reaction is performed by the action of the ring closing catalyst and the dehydrating agent.
The heat treatment temperature of the thermal ring closure method is preferably 150 to 500 ° C. If the heat treatment temperature is lower than this range, it is difficult to sufficiently close the ring, and if it is higher than this range, the deterioration proceeds and the film tends to become brittle. A more preferable embodiment includes a two-stage heat treatment step having an initial stage heat treatment and a subsequent stage heat treatment in which a heat treatment is performed at 150 to 250 ° C. for 3 to 20 minutes and then heat treatment at 350 to 500 ° C. for 3 to 20 minutes.
The timing for adding the ring-closing catalyst to the polyamic acid solution is not particularly limited, and may be added in advance before the polymerization reaction for obtaining the polyamic acid. Specific examples of the ring-closing catalyst include aliphatic tertiary amines such as trimethylamine and triethylamine, and heterocyclic tertiary amines such as isoquinoline, pyridine, and betapicoline. Among them, heterocyclic tertiary amines are mentioned. At least one amine selected from is preferred. Although the usage-amount of a ring-closing catalyst with respect to 1 mol of polyamic acids does not have limitation in particular, Preferably it is 0.5-8 mol.
The timing of adding the dehydrating agent to the polyamic acid solution is not particularly limited, and may be added in advance before the polymerization reaction for obtaining the polyamic acid. Specific examples of the dehydrating agent include aliphatic carboxylic acid anhydrides such as acetic anhydride, propionic anhydride, butyric anhydride, and aromatic carboxylic acid anhydrides such as benzoic anhydride. Among them, acetic anhydride, benzoic anhydride, etc. Acids or mixtures thereof are preferred. Moreover, the usage-amount of the dehydrating agent with respect to 1 mol of polyamic acids is not particularly limited, but is preferably 0.1 to 4 mol. When a dehydrating agent is used, a gelation retarder such as acetylacetone may be used in combination. Whether it is a thermal cyclization reaction or a chemical cyclization method, the polyimide film precursor (green film) formed on the support may be peeled off from the support before it is completely imidized. You may peel after conversion.

The thickness of the polyimide film in the present invention is 7 μm or less.
Conventionally, it is difficult to industrially stably produce a long film of polyimide film of 7.0 μm or less, particularly 5 μm or less, and these obtained ultrathin polyimide films have extremely large thickness spots. For example, the thickness variation of a commercially available 7.5 μm polyimide film is about 25%, and there was a problem in quality in electronic parts that require dimensional accuracy. The present invention does not solve these problems. It is what. Although the minimum of the thickness of the polyimide film in this invention is not specifically limited, 0.3 micrometer or more is preferable when an application, handling property, etc. are considered.
The thickness of the polyimide film can be easily controlled by the amount of the polyamic acid solution applied to the support and the concentration of the polyamic acid solution.
The polyimide film of the present invention is preferably provided with a lubricant in the polyimide to give fine irregularities on the film surface to improve the slipping property of the film.
As the lubricant, inorganic or organic fine particles having an average particle diameter of about 0.03 to 1 μm can be used. Specific examples include titanium oxide, alumina, silica, calcium carbonate, calcium phosphate, calcium hydrogen phosphate, calcium pyrophosphate, Examples include magnesium oxide, calcium oxide, and clay minerals.

In the present invention, a method for obtaining a polyimide film having a thickness of 7 μm or less, in which these thickness spots are 20% or less, is not particularly limited, but the following method is a TD direction (width direction or lateral direction). (Also referred to as thickness).
(1) Polyamic acid obtained by reacting aromatic tetracarboxylic acids and aromatic diamines is cast and dried to obtain a polyimide precursor film, and the polyimide precursor film is connected to both ends in the width direction of the film. Film ends are gripped by a large number of clips or pierced by a large number of pins provided on a pin sheet, and imidized by a tenter method that transports the film in a stretched state in the width direction and / or the transport direction. Is a polyimide film manufacturing method for obtaining a polyimide film having a thickness of 7 μm or less, and film holding at both end portions in the width direction of the polyimide precursor film is imidized with a polyimide precursor (polyamic acid) film and a narrow width The easy-adhesive polyimide film with an adhesive layer on the polyimide film Process for producing a polyimide film is fixed by and or stabbing it,
(2) A so-called polyimide precursor obtained by slitting a polyimide precursor film obtained by casting and drying a polyamic acid obtained by reacting an aromatic tetracarboxylic acid and an aromatic diamine with the narrow polyimide film. The method of said (1) which is a body film is mentioned.

Here, the thin film prepared separately is not particularly limited in the case of a polyimide precursor film or an easily adhesive polyimide film provided with an adhesive layer, but is processed polyimide precursor film The same diamine and the same tetracarboxylic acid are preferred, and separately from the polyimide film to be produced, the same polyamic acid solution is cast and dried to prepare another polyimide precursor film and prepared by slitting in advance beforehand A polyimide film obtained by imidizing a polyimide precursor film or a thin polyimide precursor film is preferable. These are slit as they are, or are prepared by slitting as an easily adhesive polyimide film provided with an adhesive layer. Can do.
The width of the narrow film is preferably 20 mm to 80 mm. Further, the thickness of the thin film prepared separately is not particularly limited, but preferably the same thickness as the precursor film to be processed (manufactured as a polyimide film), preferably 5 μm to 13 μm, If it is less than 5 μm, the reinforcing effect of the overlay tends to be reduced, and if it exceeds 13 μm, the reinforcing effect of the overlay tends to be difficult to reach the precursor film to be produced as a polyimide film.
Although it does not specifically limit as an adhesive agent used for the easily adhesive layer laminated | stacked on the narrow polyimide film in this invention, There exist a thermoplastic adhesive and a thermosetting adhesive.

As the thermoplastic adhesive, an adhesive from a thermoplastic (thermocompression bonding) polyimide resin is preferable from the viewpoint of heat resistance and adhesion to a film, etc., and as these thermoplastic (thermocompression bonding) polyimide resin, A thermoplastic polyimide resin that can be thermocompression bonded at a temperature of about 230 to 400 ° C. is preferred. As such a thermocompression bonding polyimide, preferably, as diamines,
APB: 1,3-bis (3-aminophenoxybenzene),
m-BP: 4,4′-bis (3-aminophenoxy) biphenyl,
DABP: 3,3′-diaminobenzophenone,
DANPG: 1,3-bis (4-aminophenoxy) -2,2-dimethylpropane,
As at least one diamine selected from: tetracarboxylic anhydride,
PMDA: pyromellitic dianhydride,
ODPS: 3,3 ′, 4,4′-diphenyl ether tetracarboxylic dianhydride,
BTDA: 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride,
BPDA: 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride α-BPDA: 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride,
ODPA: 4,4′-oxydiphthalic dianhydride,
Polyimide obtained from at least one tetracarboxylic dianhydride selected from can be used. These can be used alone or in combination of two or more. Further, other diamines or tetracarboxylic acid anhydrides exemplified above can be used in combination within the range not exceeding 50 mol% of each of the diamines or tetracarboxylic acid anhydrides.
In addition, polyamide imide resins, polyether imide resins, polyester imide resins, and the like can be used alone or in appropriate combination.
In addition, as long as the advantages of the present invention are not impaired, a thermosetting adhesive such as an epoxy-based or cyanate-based adhesive may be mixed with the thermoplastic adhesive of the present invention, and this thermosetting in the entire adhesive layer. The proportion of adhesive is at most 40%.

As the thermosetting adhesive, epoxy type, urethane type, acrylic type, silicone type, polyester type, imide type, polyamide imide type and the like can be used. For example, flexible resin such as polyamide resin and hard type such as phenol are mainly used. And those containing an epoxy resin and imidazoles as a main component. More specifically, examples include those obtained by appropriately mixing dimer acid-based polyamideimide resin, room temperature solid phenol, room temperature liquid epoxy, and the like. It has moderate softness, hardness, adhesion, etc., and can easily control the semi-cured state. Further, as the polyamideimide resin, those having a weight average molecular weight of 5,000 to 100,000 are suitable. In addition to phenolic resins and epoxy resins, maleimide resins, resole resins, triazine resins and the like can also be used. Nitrile butadiene rubber can also be blended and copolymerized. Thermosetting adhesives are controlled in a cured state to a semi-cured state. Methods for controlling the cured state include, for example, heating with hot air when applying and drying the adhesive on a substrate, and far / near. Examples include heating with infrared rays and irradiation with electron beams. In the control by heating, it is preferable to heat at 100 to 200 ° C. for 1 to 60 minutes, more preferably at 130 to 160 ° C. for 5 to 10 minutes.
The thermosetting adhesive of the present invention is used once in a semi-cured state. The semi-cured state is a solid state that can be softened or melted by heating and finally cured.

  In the present invention, when the polyimide precursor film is imidized (such as heat treatment) with a film end fixed tenter, the film end gripping at both side ends in the width direction of the film is a number of pin sheets and A tenter type that consists of a large number of pins arranged on each pin sheet, the pins are pierced at both ends of the film by a pressing brush roll, and conveys the film in a stretched state in the width direction and / or the conveyance direction In the polyimide film manufacturing method which has a process part, it is set as the preferable aspect that it is the state where it overlapped with the thin film prepared separately from the polyimide precursor film processed at the part stabbed with a pin. .

  The shape of the high part in the pin sheet which has a part higher than the pin base installed outside with respect to the width direction of the pin sheet as a preferred embodiment of the present invention is not particularly limited, and the pin base is a surface in which the pin is implanted It is only necessary to have a function that the film is higher in position and the film does not contact the pin base. For example, only the outer side in the width direction of the pin sheet (the outer position in the width direction in which the pin is not implanted) is higher. It may be a base that contacts the film only, or may be a pin sheet in which the pin base is inclined outward in the width direction. For example, in the case of a base, the shape and size of the base are: Preferably, (1) the height of the base is lower in the range of 3 to 8 mm than the tip of the pin, more preferably lower in the range of 4 to 6 mm, and the height of the base is 3 from the tip of the pin. If the height is less than m, the depth of the pin piercing both ends of the film is shallow, and the frequency of the film coming off from the pin during the subsequent heat treatment process is increased, which is not preferable. If the thickness is lower than 8 mm, the resistance becomes large when the film is removed from the pin sheet after the heat treatment, which leads to tearing of both end portions of the worst film. (2) The height of the base is higher in the range of 0.5 to 5 mm than the base on which the pins are installed, more preferably in the range of 2 to 3 mm, and the film on the pin sheet During gripping, the pin insertion depth of the film by the holding brush roll is stably determined, and a direct heat transfer suppression effect from the pin sheet to the film gripping portion is manifested. As a result, the temperature between the film center and the gripping portion is exhibited. The difference is reduced, and the difference in breaking strength during film conveyance is reduced. As a result, troubles such as film breakage during peeling of the film from the pin sheet in the tenter and after heat treatment in the tenter can be reduced. On the other hand, if the height of the base is less than 1 mm from the pedestal on which the pins are installed, the direct heat transfer suppression effect from the pin sheet to the film gripping portion is reduced. The temperature difference with the gripping part becomes large, and the difference in breaking strength during film conveyance becomes large, resulting in troubles such as film breakage in the tenter, which is not preferable. If it is higher than 5 mm than the pedestal, it is not preferable because it promotes contamination of the pin sheet itself in the heat treatment step. Further, (3) it is preferable that the periphery of the table is chamfered, and if the chamfering is not performed, the film in contact with the periphery of the table is not preferable. Also, (4) providing a cavity in the pedestal on which the pins are installed has a direct heat transfer suppression effect from the pin sheet to the film gripping part, resulting in a temperature difference between the film center part and the gripping part. Is reduced, and the difference in breaking strength during film conveyance is reduced, resulting in prevention of troubles such as film breakage in the tenter.

In a polyimide film manufacturing apparatus in which a base is installed on the outer side with respect to the width direction of the pin sheet, when the pin pierces both side ends of the film, a melting point or a softening point is 150 ° C. or higher and a tensile elastic modulus is 4 GPa or higher. It is also a preferred embodiment to use means for piercing the film end with a pin with a member having a brush made of a bristle material.
Further, in this presser brush roll, the member of the presser brush roll that comes into contact with a portion higher than the pin base installed outside in the width direction is higher in rigidity than the member in the inner part in the width direction, Specifically, it is more preferable that the member installed on the outer side in the width direction of the pressing brush roll is a metal wire brush-shaped member or a metal cylindrical member.

A member having a brush made of a bristle material having a melting point or softening point of 150 ° C. or higher and a tensile elastic modulus of 4 GPa or higher is not particularly limited, but a brush roll provided with a brush on a cylindrical plane circumference can be preferably used. .
A brush made of a bristle material having a melting point or softening point of 150 ° C. or more and a tensile modulus of elasticity of 4 GPa or more has the properties so that the film can be pierced uniformly and its function deteriorates even when used for a long time. Is extremely small. When a material having no physical properties is used, the above two points cannot be satisfied at the same time.
A brush made of a bristle material having a melting point or softening point of 150 ° C. or higher and a tensile elastic modulus of 4 GPa or higher is not particularly limited as long as it has this physical property. For example, a high elastic modulus polymer fiber , Carbon fiber, glass fiber, and the like, more preferably polymer materials such as polymer fiber, and aromatic polyamide such as CONEX (manufactured by Teijin Ltd.).

The pin tenter gripping portion according to the present invention is composed of a large number of pins arranged on each pin sheet as shown in, for example, FIG. 1 and FIG. 2, and a large number of these individual pin sheets are arranged to convey the film. In addition, before the polyimide precursor film to be processed as shown in FIG. 2 is pierced into the pin of the pin sheet, it is overlapped with a thin film prepared separately on both sides thereof, and a pressing brush roll You can pierce the pin with.
In the present invention, as a preferred embodiment, a cooling means is provided at a position immediately before the film heat treatment is finished and the pin or pin sheet turns and returns to the position where film gripping is started. When the film is sufficiently cooled and the film is pierced at both ends by the pins, the film holding uniformity is maintained, and the holes are enlarged or broken in the width direction or the conveying direction of the film at the holes where the pins are entrapped. Is suppressed. As the cooling means, either air cooling or water cooling may be used, and a refrigerant other than air or water may be used. From the viewpoint of cooling efficiency, it is preferable to use a liquid refrigerant. Further, considering that the tenter itself is heated above the ignition point of a general organic solvent, it is most preferable to use a cooling means based on water cooling specifications.

By providing this cooling means, when the pins and the pin sheet start gripping both ends of the film and start conveyance, the pins etc. are kept at a high temperature when they are heated to a high temperature such as one end heat treatment temperature such as 450 ° C. and there is no cooling means. In the piercing of both ends of the film with this high-temperature pin, it is difficult to maintain uniformity of film gripping, and the hole expands or breaks in the film width direction or the conveyance direction at the hole where the pin is bitten. Can easily occur, and problems such as an increase in distortion in the entire film and an increase in film thickness unevenness can be solved to some extent.
Furthermore, in the present invention, as a preferred embodiment, in the pin arrangement of the pin tenter, the individual pins arranged on the innermost side in the film width direction during film conveyance are mutually different from each other in the individual pin sheet in the film conveyance direction. It is preferable that the pin sheets are all arranged at equal intervals.

  Further, in the present invention, when the polyimide precursor film is imidized (heat treatment or the like) with a film end fixed type tenter, the film end gripping at both side ends in the width direction of the film is constituted by a number of clips. In the polyimide film manufacturing method having a tenter type processing unit that transports the film in a state of being stretched in the width direction and / or the transport direction, the clip is made by gripping both side ends of the film, A preferred embodiment is that the polyimide precursor film to be treated and a thin film prepared separately are overlaid.

  In the present invention, when the polyimide precursor film is subjected to imidization treatment (heat treatment, etc.) with a film end fixed type tenter, film end gripping at both end portions in the film width direction is endless. In the polyimide film manufacturing method, the clip has a clip tenter type processing section for transporting the film while being stretched in the width direction and / or the transport direction. It is a preferable aspect that it is in a state where it is overlapped with a thin film prepared separately from the polyimide precursor film to be processed at the portion sandwiched between.

  In the present invention, the clip portion of the end fixing tenter for heat-treating the polyimide film is not particularly limited as long as it is a known clip portion, but preferably uses a breathable heat-resistant material for the clip portion, The form and properties are not particularly limited, but preferably a breathable heat-resistant material that is a porous object or fiber aggregate having a thermal decomposition temperature of 400 ° C. or lower is used. Porous ceramics can be used as the breathable heat-resistant material in the present invention. There is no particular restriction on the material of the ceramic itself, and it is sufficient to use a single material or a plurality of materials such as alumina, calcia, magnesia, silica, etc. The porosity indicating the degree of porosity is preferably 30% or more by volume ratio, preferably 40% or more. Is more preferably 50% or more. When the degree of porosity is lower than this range, free emission of volatile components from the polymer film is prevented. On the other hand, if it exceeds 90%, the ceramic itself becomes brittle and becomes impractical. Similarly, as the porous body, foamed cement, gypsum, glass, metal, and other inorganic solids such as phosphates, carbonates, sulfates, and metal acid salts can be used.

As the breathable heat-resistant material in the present invention, an aggregate of inorganic fibers can be used. As the inorganic fibers used in the present invention, carbon fibers, alumina wool, glass wool, asbestos, various glass fibers, and the like can be used. These may be woven, non-woven, or thick like felt.
An aggregate of metal fibers can be used as the breathable heat-resistant material in the present invention. As the metal species, a stainless steel material having excellent corrosion resistance is preferable.
An aggregate of heat-resistant polymer fibers can be used as the breathable heat-resistant material in the present invention. As the heat resistant polymer fiber, aromatic polyamide fiber, polyimide fiber, polybenzoxazole fiber, polybenzothiazole fiber, polybenzimidazole fiber, polyimide benzoxazole fiber, or the like can be used.

It is more preferable that the tenter of the present invention formed by sandwiching the film end gripping with a plurality of clips has means for cooling so that the temperature of the gripping portion where the clip is in contact with the film is less than 180 ° C.
Hereinafter, the clip cooling means will be described in detail. A tenter using such a clip as a fixing means is called a clip tenter. Clip tenter clips are often combined with drive chains and installed as endless tracks. As for the drive chain of the clip tenter, a type that passes through the inside of the processing furnace is known for both reciprocation, and a type that the return path passes through the inside of the processing furnace is known. It is preferable to apply to. In the case of such a type, the entire apparatus can be made compact.
As shown in FIG. 3, in a processing chamber that receives a heat treatment or the like, a large number of clip blocks in which clips are arranged are arranged at both ends of the film, and these clips grip and convey both ends of the film. These clips run parallel to each other at both ends of the film, and are kept at a very high temperature for heat treatment of the film. At least in this processing chamber, the clips are also exposed to high temperature, and the film heat treatment is completed. It turns and grips the film again in its original position.
In the present invention, the cooling of the clip and the clip block is preferably performed from the return path of the drive chain to the clipping zone on the entrance side of the processing furnace.

  In the conventional tenter type transfer device, when these clips grip the both ends of the film and start to transfer, one end is heated to a heat treatment temperature of 490 ° C., for example, 490 ° C., and there is no cooling means or temperature control means, and temperature variation is maintained at a high temperature. In the gripping of both ends of the film by the clip, the film gripping uniformity is difficult to be maintained, film thickness spots and cracks are likely to occur in the vicinity of the portion sandwiched between the clips, and the film breaks easily due to the expansion of the cracks. Furthermore, an increase in distortion and an increase in film thickness unevenness occur throughout the film. Therefore, in the present invention, a cooling means is provided at a position immediately before the clip is turned after the film heat treatment is finished and returns to the position where film gripping is started, and the clip is sufficiently cooled and temperature controlled at the time of starting film gripping. Therefore, uniformity of film gripping by the clip can be maintained, tearing in the vicinity of the clip, distortion reduction in the entire film, and reduction in film thickness unevenness can be achieved.

As a cooling means in the present invention, either air cooling or water cooling may be used, and a refrigerant other than air or water may be used. From the viewpoint of cooling efficiency, it is preferable to use a liquid refrigerant. Further, considering that the tenter itself is heated above the ignition point of a general organic solvent, it is most preferable to use a cooling means based on water cooling specifications. In order to prevent dew condensation in the vicinity of the cooling part, it is preferable to control the dew point of the cold air when air is used as the atmosphere and the refrigerant.
Furthermore, in the present invention, it is preferable to include a means for measuring the temperature of the clip portion and a control system for controlling the degree of cooling according to the measurement result. As the temperature measuring means, a known means such as a thermocouple or a radiation thermometer can be used. The control system may use normal negative feedback control.

  The thickness unevenness of the ultra-thin polyimide film having a thickness of 7 μm or less in the present invention is essential to be 20% or less, preferably 15% or less, more preferably 10% or less. When this thickness unevenness exceeds 20%, when this film is used as a heat-resistant insulating material for an electronic component, it causes a defect in the dimensional accuracy of the electronic component, and further has many problems in the electrical quality of the electronic component. .

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited by a following example. In addition, the evaluation method of the physical property in the following examples is as follows.

1. Reduced viscosity of polyamic acid (ηsp / C)
A solution dissolved in N-methyl-2-pyrrolidone (or N, N-dimethylacetamide) so that the polymer concentration was 0.2 g / dl was measured at 30 ° C. with an Ubbelohde type viscosity tube. (When the solvent used for preparing the polyamic acid solution was N, N-dimethylacetamide, the polymer was dissolved using N, N-dimethylacetamide and measured.)
2. The thickness of the polyimide film and the thickness unevenness The thickness of the film was measured using a micrometer (Millitron 1254D, manufactured by Finelfu).
About the thickness spot in this invention, it measured to the width direction and the longitudinal direction.
For the width direction (TD direction), the thickness of the film having a width of 500 mm taken from the remaining width excluding the width of 50 mm at both ends of the film was measured at intervals of 1 cm in the width direction, and the average thickness and the maximum value therebetween. The minimum value was calculated using the following formula. About a longitudinal direction (MD direction), it measured for 5 m by a 5-cm space | interval of the longitudinal direction, and calculated the average, the maximum value, and the minimum value in the meantime using the following Formula.
Thickness unevenness (%) = ((maximum value−minimum value) / average thickness) × 100

3. Test specimens obtained by cutting a polyimide film to be measured into strips of 100 mm × 10 mm in the flow direction (MD direction) and the width direction (TD direction), respectively. It was. Using a tensile tester (manufactured by Shimadzu Corporation, Autograph (trade name), model name AG-5000A) under the conditions of a tensile speed of 50 mm / min and a distance between chucks of 40 mm, the tensile modulus of elasticity in each of the MD direction and TD direction, Tensile rupture strength and tensile rupture elongation were measured.
4). Film linear expansion coefficient (CTE)
The expansion / contraction rate was measured under the following conditions, and the range from 30 to 300 ° C. was divided at 15 ° C. intervals and obtained from the average value of the expansion / contraction rate / temperature of each divided range. The meanings of the MD direction and the TD direction are the same as described above.
Device name: TMA4000S manufactured by MAC Science
Sample length; 20mm
Sample width: 2 mm
Temperature rise start temperature: 25 ° C
Temperature rising end temperature: 400 ° C
Temperature increase rate: 5 ° C / min
Atmosphere: Argon

[Reference Example 1]
(Preliminary dispersion of inorganic particles)
1.22 parts by mass of spherical particles of amorphous silica Seahoster KE-P10 (manufactured by Nippon Shokubai Co., Ltd.), 420 parts by mass of N-methyl-2-pyrrolidone, the wetted part of the container, and the piping for infusion are austenitic stainless steel The mixture was placed in a container of SUS316L and stirred with a homogenizer T-25 basic (manufactured by IKA Labortechnik) at a rotation speed of 1000 rpm for 1 minute to obtain a preliminary dispersion. The average particle size in the preliminary dispersion was 0.11 μm.
(Preparation of polyamic acid solution)
A nitrogen inlet tube, a thermometer, a liquid contact part of a container equipped with a stirring rod, and an infusion pipe were replaced with nitrogen in the reaction container made of austenitic stainless steel SUS316L, and then 223 parts by mass of 5-amino-2- ( p-Aminophenyl) benzoxazole was added. Next, 4000 parts by mass of N-methyl-2-pyrrolidone was added and completely dissolved, and then the preliminary dispersion obtained above was added with 420 parts by mass and 217 parts by mass of pyromellitic dianhydride. When the mixture was stirred at ° C. for 24 hours, a brown viscous polyamic acid solution A was obtained. The reduced viscosity (ηsp / C) was 3.8 dl / g.

[Reference Example 2]
The nitrogen inlet tube, the thermometer, the wetted part of the vessel equipped with the stirring rod, and the infusion pipe were replaced with nitrogen in the reaction vessel made of austenitic stainless steel SUS316L, and then 5-amino-2- (p-aminophenyl) ) After adding 223 parts by mass of benzoxazole and 4416 parts by mass of N, N-dimethylacetamide and completely dissolving them, Snowtex DMAC-ST30 (manufactured by Nissan Chemical Industries, Ltd.) 40 in which colloidal silica is dispersed in dimethylacetamide .5 parts by mass (including 8.1 parts by mass of silica) and 217 parts by mass of pyromellitic dianhydride are added and stirred at a reaction temperature of 25 ° C. for 24 hours to obtain a brown and viscous polyamide acid solution B. It was. Ηsp / C of this product was 4.0 dl / g.

[Reference Example 3]
(Preliminary dispersion of inorganic particles)
7.6 parts by weight of amorphous silica spherical particles Seahoster KE-P10 (manufactured by Nippon Shokubai Co., Ltd.), 390 parts by weight of N-methyl-2-pyrrolidone, the liquid contact part of the container, and the infusion pipe are austenitic stainless steel SUS316L And stirred for 1 minute at a rotation speed of 1000 rpm with a homogenizer T-25 basic (manufactured by IKA Labortechnik) to obtain a preliminary dispersion.
(Preparation of polyamic acid solution)
Nitrogen introduction tube, thermometer, liquid contact part of container equipped with stirring rod, and infusion pipe were replaced with nitrogen in the reaction container made of austenitic stainless steel SUS316L, and then 200 parts by mass of 4,4′-diaminodiphenyl ether Put. Next, after 3800 parts by mass of N-methyl-2-pyrrolidone was added and completely dissolved, 390 parts by mass and 217 parts by mass of pyromellitic dianhydride were added to the preliminary dispersion obtained above. When the mixture was stirred at 0 ° C. for 5 hours, a brown viscous polyamic acid solution C was obtained. The reduced viscosity (ηsp / C) was 3.7 dl / g.

[Reference Example 4]
(Preliminary dispersion of inorganic particles)
Amorphous silica spherical particle Seahoster KE-P10 (manufactured by Nippon Shokubai Co., Ltd.), 3.7 parts by mass, N-methyl-2-pyrrolidone, 420 parts by mass, the container wetted part, and the infusion pipe are austenitic stainless steel SUS316L And stirred for 1 minute at a rotation speed of 1000 rpm with a homogenizer T-25 basic (manufactured by IKA Labortechnik) to obtain a preliminary dispersion.
(Preparation of polyamic acid solution)
The wetted part of the vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod, and the infusion piping were purged with nitrogen in the reaction vessel made of austenitic stainless steel SUS316L, and then 108 parts by mass of p-phenylenediamine was added. . Next, after 3600 parts by mass of N-methyl-2-pyrrolidone was added and completely dissolved, 420 parts by mass and 292.5 parts by mass of 3,3 ′, 4,4 ′ -Diphenyltetracarboxylic dianhydride was added and stirred at 25 ° C for 12 hours to obtain a brown viscous polyamic acid solution D. The reduced viscosity (ηsp / C) was 4.5 dl / g.

[Reference Example 5]
After replacing the inside of the reaction vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod with nitrogen, 930 parts by mass of 1,3-bis (4-aminophenoxy) benzene was introduced, and 15000 parts by mass of dimethylacetamide were introduced uniformly. After stirring well, 40.5 parts by mass of Snowtex (trade name) DMAC-Zl (manufactured by Nissan Chemical Industries, Ltd.) obtained by dispersing colloidal silica in dimethylacetamide (including 8.1 parts by mass of silica) The solution was cooled to 0 ° C., 990 parts by mass of 4,4′-oxydiphthalic anhydride was added, and the mixture was stirred for 17 hours. A pale yellow and viscous polyamic acid solution (E) was obtained. The solution obtained had a ηsp / C of 3.1 dl / g.

(Preparation of easy-adhesive narrow film)
Using the polyamic acid solutions A and C obtained in the Reference Example, each was separately coated on a non-lubricant surface of a polyethylene terephthalate film A-4100 (manufactured by Toyobo Co., Ltd.) using a comma coater (coating The workpiece was dried at 90 ° C. for 60 minutes. The polyamic acid film that became self-supporting after drying was peeled from the support and cut at both ends to obtain a green film having a thickness of 15 μm and a width of 1200 mm. The obtained green film was subjected to heat treatment with the apparatus shown in FIGS. 1 and 2 by gripping both ends with a pin tenter under the conditions of a pin sheet, a brush roll, a pressing roll, and a supporting jig as shown in parentheses below. The pins are arranged so that the pin interval is constant when the pin sheets are arranged, the pin height from the pin base is 8 mm, the pin sheet interval is 1140 mm, and the length of the pin sheet in the longitudinal direction is The length in the width direction is 95 mm, the length in the longitudinal direction of the table set outside the pin sheet in the width direction is 95 mm, the length in the width direction is 15 mm, and the periphery of the table is chamfered. did. In addition, the brush roll has a two-layer structure using two kinds of materials in the width direction, made of Conex with a strand diameter of 0.3 mm, and on the outside a metal element with a strand diameter of 0.5 mm. A line was placed.
(The pin sheet has a flat plate shape, the distance between the press roll and the film grip start portion is 150 mm, the support jig uses a Teflon (registered trademark) bar, and the distance between the support jig and the film grip start portion is 170 mm).
The heat treatment settings for the tenter are as follows. The first stage was heated at 180 ° C. for 5 minutes and the temperature was raised at a rate of 4 ° C./second, and the second stage was heated at 460 ° C. for 5 minutes under two conditions, ignoring productivity and speed. And the imidization reaction was allowed to proceed. Then, it cooled to room temperature in 5 minutes, wound up in roll shape, and obtained the 9-micrometer-thick polyimide film A and the polyimide film C which exhibit the brown color from each polyamic-acid solution.
A polyamic acid solution (E) diluted 10 times with DMAC (dimethylacetamide) was prepared, and coated on one side of the obtained polyimide film A and polyimide film C using a bar coater. Subsequently, it dried at 90 degreeC for 10 minute (s), and the easily-adhesive polyimide film A and the easily-adhesive polyimide film C were obtained. The ratio of the easy-adhesion layer in these to the thickness 1 of the polyimide film A and the polyimide film C is 0.1 / 1. The resulting easy-adhesive polyimide film A and easy-adhesive polyimide film C were each slit to prepare a narrow long slit film A having a width of 35 mm and a narrow long slit film C.

<Example 1>
The polyamic acid solution A obtained in Reference Example 1 was coated on the non-lubricant surface of polyethylene terephthalate film A-4100 (manufactured by Toyobo Co., Ltd.) using a comma coater (coating width 1240 mm, true of backup roll). The film was dried at 90 ° C. for 60 minutes. The polyamic acid film which became self-supporting after drying was peeled off from the support and cut at both ends to obtain a green film having a thickness of 8.2 μm and a width of 1200 mm. In the apparatus shown in FIG. 1 and FIG. 2, the following brackets are used to superpose the 35 mm wide narrow slit film A (adhesive narrow slit film A) on both side ends of the obtained green film. As shown in the figure, both ends were gripped by a pin tenter under the conditions of a pin sheet, a brush roll, a pressing roll, and a support jig, and heat treatment was performed. The pins are arranged so that the pin interval is constant when the pin sheets are arranged, the pin height from the pin base is 8 mm, the pin sheet interval is 1140 mm, and the length of the pin sheet in the longitudinal direction is The length in the width direction is 95 mm, the length in the longitudinal direction of the table set outside the pin sheet in the width direction is 95 mm, the length in the width direction is 15 mm, and the periphery of the table is chamfered. did. In addition, the brush roll has a two-layer structure using two kinds of materials in the width direction, made of Conex with a strand diameter of 0.3 mm, and on the outside a metal element with a strand diameter of 0.5 mm. A line was placed.
(The pin sheet has a flat plate shape, the distance between the press roll and the film grip start portion is 150 mm, the support jig uses a Teflon (registered trademark) bar, and the distance between the support jig and the film grip start portion is 170 mm).
The heat treatment settings for the tenter are as follows. The first stage was heated at 180 ° C. for 5 minutes and the heating rate was 4 ° C./second, and the second stage was heated at 460 ° C. for 5 minutes for 2 minutes to proceed the imidization reaction. Then, it cooled to room temperature in 5 minutes, the part which the narrow film of the both ends of the film overlapped was cut off with the slitter, it rolled up in roll shape, and the polyimide film A which exhibits brown was obtained. Table 1 shows the measurement results such as the conveyance state during the heat treatment and the characteristics of the obtained polyimide film.

The flatness and effective width of the film were defined as follows.
First, the obtained film was spread on a surface plate having a clean surface, and a portion where a space was left between the surface plate due to undulation at the end of the film was regarded as a portion having poor flatness. The ends of the film were not lifted from the surface of the platen, and both ends of the film were cut until the entire film was in close contact with the platen, and the film width at that time was defined as the effective width.
Also, for pin tearing, the film tearing in the width direction and the vertical direction at the pin part is visually judged at a portion about 10 m from the top of the film, and pin holes (500 in total) adjacent to each other in the vertical direction. Those having 10 or more connected pieces were rated as x, those having about 10 to 3 pieces were evaluated as Δ, and those having two or less connected as ◯.
The peelability from the pin sheet is evaluated as a visual evaluation of the state when the heat treatment is finished and the film is peeled off and peeled off from the pin sheet by the roll. The smooth peeling is good, and the film is caught slightly on the pin. In the case where the film tears in the flow direction due to catching, it was regarded as defective.

<Examples 2 to 8>
Using the polyamic acid solutions A to D obtained in Reference Examples 1 to 4 and the same as in Example 1 except that the coating thickness and the narrow slit film shown in the table are overlapped on both ends. Each polyimide film was obtained.
The evaluation was made in the same manner. The results are shown in Table 1.

<Comparative Examples 1-4>
Using the polyamic acid solutions A to D obtained in Reference Examples 1 to 4, a green film having a thickness of 8.2 μm and a width of 1200 mm is directly used without overlapping the narrow slit film on both side ends. Each polyimide film was produced in the same manner as in Example 1 except that it was used and processed, but the pin holes at the pin stab site were torn mainly in the vertical direction, the film became wrinkles, and a fracture site was formed. Thus, a long polyimide film that could be continuously evaluated could not be produced.

<Examples 9 to 10>
Using the polyamic acid solutions A and D obtained in the reference example, green films having a thickness of 12 μm and a width of 1200 mm were obtained, and overlapped with the narrow and long slit film A at both end portions thereof. A polyimide film having a thickness of 7 μm was produced in the same manner as in Example 1 except that a film having a degree of 4 (μm) was used. The evaluation was made in the same manner. The results are shown in Table 2.

<Comparative Examples 5-6>
Using the polyamic acid solutions A and D obtained in the reference example, green films having a thickness of 12 μm and a width of 1200 mm were obtained, and processing was performed without overlapping with the narrow slit film A at both side ends and backup. A polyimide film having a thickness of 7 μm was produced in the same manner as in Example 1 except that rolls having a roundness of 4 (μm) were used. The evaluation was made in the same manner. The results are shown in Table 2.

(Preparation of narrow polyimide precursor film)
Using the polyamic acid solutions A and C obtained in the Reference Example, each was separately coated on a non-lubricant surface of a polyethylene terephthalate film A-4100 (manufactured by Toyobo Co., Ltd.) using a comma coater (coating The workpiece was dried at 90 ° C. for 60 minutes. The polyamic acid film which became self-supporting after drying was peeled from the support and cut at both ends to obtain a green film (polyimide precursor film) having a thickness of 8 μm and a width of 1200 mm. Each of the obtained green films was slit to prepare a narrow long slit polyimide precursor film A and a narrow long slit polyimide precursor film C having a width of 30 mm.

<Example 11>
The polyamic acid solution A obtained in Reference Example 1 was coated on the non-lubricant surface of polyethylene terephthalate film A-4100 (manufactured by Toyobo Co., Ltd.) using a comma coater (coating width 1240 mm, true of backup roll). The product was dried at 90 ° C. for 60 minutes using a circularity of 4 (μm). The polyamic acid film which became self-supporting after drying was peeled off from the support and cut at both ends to obtain a green film having a thickness of 8.2 μm and a width of 1200 mm.
The obtained green film is a clip shown in FIGS. 3 to 4 having a fiber diameter as a material of a portion in contact with the film while superimposing the narrow slit polyimide precursor film A having a width of 30 mm on both side ends. A clip using a felt made of 8 μm Naslon fiber (thickness of about 2 mm) was used, equipped with a temperature measuring means for the clip gripping part by a radiation thermometer, and further provided with a cooling part as schematically shown in FIG. Pass through clip tenter, clip sheet interval is 1140mm, that is, each 30mm of green film is gripped by clip, first stage is 170 ° C for 5 minutes, second stage is 220 ° C for 5 minutes, third stage is 480 ° C for 5 minutes The imidation reaction was allowed to proceed by heating at. The temperature at the clip gripping part was controlled in the range of 160 ° C. plus or minus 5 ° C. Here, NASLON fiber is a stainless steel fiber manufactured by Nippon Seisen Co., Ltd.
The conveyance state of the film was good, and “clip disengagement” did not occur in the tenter. Also, almost no film tearing was observed even at the clip gripping portion at the tenter exit.
The obtained film was cooled to room temperature, portions with poor flatness at both ends of the film were cut off with a slitter, wound up into a roll shape, and the polyimide film of Example 11 exhibiting brown color was obtained. The properties of the obtained polyimide film are shown in Table 3.

<Examples 12 to 18>
Using the polyamic acid solutions A to D obtained in Reference Examples 1 to 4, respectively, except that the coating thickness and the narrow slit film shown in the table are overlapped on both ends, respectively, in the same manner as in Example 11. The polyimide film was obtained.
The evaluation was made in the same manner. The results are shown in Table 3.

<Comparative Examples 7 to 10>
Using the polyamic acid solutions A to D obtained in Reference Examples 1 to 4, a thin long polyimide precursor slit film is not overlapped on both side ends, and a green having a thickness of 8.2 μm and a width of 1200 mm Each polyimide film was produced in the same manner as in Example 11 except that the film was used as it was, but the film became wrinkled due to the formation of a broken part such as tearing in the longitudinal direction at the clip holding part. The long polyimide film which can be evaluated continuously could not be produced.

  As described above, in the preferred embodiment of the present invention, when the polyamic acid solution is cast on a support, a back-up roll with high roundness is used, and the film end-fixed tenter in the step of imidizing is used. By manufacturing the film by stacking and fixing the polyamic acid film to be imidized and another narrow film on both side edges in the width direction of the film, the film can be manufactured in the vertical and width directions. It is possible to solve the problem of breakage, the occurrence of curling, quality defects due to wrinkles and distortions, etc., and a long ultrathin polyimide film with a thickness of 7 μm or less with little unevenness is stable. The resulting ultra-thin polyimide film is a film with excellent uniformity with few thickness spots, and it can be used for electronic components such as flexible circuits. It can contribute to the improvement of the law accuracy and quality.

The outline of the pin sheet | seat which provided the stand in the width direction outer side of the pin which contacts the film in the pin tenter type film processing machine which is one of the preferable aspects of this invention is shown. (A) is a front view, (b) is a side view. The outline of the pin insertion part of the film in the pin tenter type film processing machine which is one of the preferable aspects of this invention is shown.

Explanation of symbols

1: Brush roll 2: Pin 3: Pin base 4: Stand 5: Support jig 6: Pressing roll 7: Polyimide precursor film

Claims (4)

  A polyimide film having a thickness of 7 μm or less obtained by casting, drying and heat-treating a polyamic acid solution obtained by reacting an aromatic tetracarboxylic acid and an aromatic diamine, and having a width direction and a longitudinal direction of the film A polyimide film characterized by having a thickness unevenness of 20% or less.   The polyimide film according to claim 1, wherein the polyimide film is a polyimide film roll having a width of 500 mm or more and a length of 100 m or more.   The polyimide film according to claim 1, wherein the aromatic diamine is an aromatic diamine having a benzoxazole structure.   The polyimide film according to claim 1, which has a linear expansion coefficient of 5 ppm / ° C. or less.

Images