JP2008272601A - Method of manufacturing flexible substrate material with metal foil, flexible substrate material with metal foil and flexible laminated board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a flexible substrate with a metal foil which is low in the rate of dimensional change after heat treatment in a manufacturing step and excellent in the appearance of a base material. <P>SOLUTION: The method of manufacturing the flexible substrate material with the metal foil has the steps of: applying a resin solution onto the metal foil and drying; removing a solvent contained in the resin solution and supplying the resultant base material (the flexible substrate material with the metal foil) to a transportation apparatus; and carrying out a high temperature treatment in the transportation apparatus, wherein the concentration (Vc) of residual solvent in the resin on the base material is 25 wt.% to 35 wt.%. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a flexible substrate material with a metal foil, a flexible substrate material with a metal foil, and a flexible laminate.

  A flexible printed circuit board is a flexible wiring board in which a conductor circuit is formed on the surface of a polymer insulating film, and has been frequently used as a means for achieving miniaturization and high density of electronic devices in recent years. Among them, those using aromatic polyimide as the insulating film dominate.

  Conventional single-sided flexible printed circuit boards using aromatic polyimide have been manufactured using polyimide film and copper foil with adhesives such as epoxy resin and acrylic resin, so this heat resistance, chemical resistance, flame resistance, electrical The properties such as properties and adhesion are governed by the adhesive used, and the various properties of polyimide cannot be fully utilized.

  As a method of solving this problem, a solution of polyamic acid (polyimide precursor) having a thermal expansion coefficient comparable to that of metal foil is directly cast on a metal foil such as copper foil by solvent removal and curing. Have been proposed (hereinafter referred to as direct coating method) (see Patent Documents 1 and 2).

  In Patent Documents 1 and 2, when the high temperature heat treatment of the resin film with metal foil is continuously performed by the horizontal roll conveyer in the direct coating method or other processes, the volume of the resin film is reduced due to solvent volatilization or reaction, and the temperature change The expansion / contraction of the metal foil and the relaxation of the base material are one of the important factors. If the residual solvent concentration (Vc) is high, the solvent cannot be completely removed in the pre-conveyance process. Furthermore, not only the appearance problem but also the cause of deterioration of the dimensional change rate is not preferable in the production of the flexible substrate material.

  As a countermeasure, the temperature condition of the post-conveying process in the furnace was set high. However, by increasing the temperature conditions in the post-conveying process, the relaxation to the resin was not good, curling and warping were large, and the dimensional change rate deteriorated. In addition, by lowering the temperature condition in the pre-conveyance process, there is a problem that the resin easily adheres to the roll during the conveyance and the substrate is easily cut.

Japanese Patent No. 1523920 Japanese Patent No. 1694181

  This invention solves the said problem, and it aims at providing the manufacturing method of the flexible board material with metal foil, the flexible board material with metal foil, and a flexible laminated board.

  As a result of intensive studies, the inventors of the present invention applied a resin solution on a metal foil and dried it in an apparatus for continuously supplying a base material and performing a high temperature treatment in order to produce a flexible substrate material. A method for producing a flexible substrate material with a metal foil for supplying a base material obtained by removing a solvent contained in a solution to a transport device and performing a high-temperature treatment comprising a pre-transport process and a post-transport process, The present invention was completed by finding a method for producing a flexible substrate material with a metal foil, wherein the residual solvent concentration (Vc) in the resin is 25% by weight or more and 35% by weight or less.

The present invention relates to the following matters.
1. A process of applying and drying a resin solution on a metal foil, a process of supplying a substrate (a flexible substrate material with a metal foil) obtained by removing a solvent contained in the resin solution to a transport apparatus, and a high-temperature treatment in the transport apparatus A method for producing a flexible substrate material with a metal foil comprising a step of performing a process, wherein the residual solvent concentration (Vc) in the resin of the base material is 25 wt% or more and 35 wt% or less Material manufacturing method.
2. The step of performing the high-temperature treatment in the transfer apparatus includes a pre-transfer process and a post-transfer process, the temperature of the pre-transfer process is less than 300 ° C., and the temperature of the post-transfer process is 300 ° C. or more. The manufacturing method of the flexible board | substrate material with metal foil of 1.
3. Item 3. The method for producing a flexible substrate material with a metal foil according to Item 1 or 2, wherein the metal foil is a copper foil.
4). Item 4. The method for producing a flexible substrate material with metal foil according to any one of Items 1 to 3, wherein the base material (flexible substrate material with metal foil) is a resin film with metal foil.
5. Item 5. The method for producing a flexible substrate material with a metal foil according to Item 4, wherein at least one of the resin components of the resin film is a polyimide resin or a polyimide precursor.
6). Item 6. The flexible substrate material with metal foil, wherein the dimensional change rate of the cured product of the flexible substrate material with metal foil is ± 0.10% or less when the line speed fluctuates, A flexible substrate material with a metal foil obtained by using the method for manufacturing a flexible substrate material with a metal foil.
7). Item 7. A flexible laminate produced by using the flexible substrate material with metal foil according to Item 6.

  By using the flexible substrate material with a metal foil of the present invention, it is possible to produce an effective flexible substrate material with a metal foil having a low dimensional change rate and a good appearance.

Hereinafter, embodiments of the present invention will be described.
For example, a resin film with a metal foil of a flexible substrate material can be formed through a manufacturing process in which a resin composition containing a resin film precursor is applied onto a metal foil, dried and cured.

  The residual solvent concentration (Vc) in the resin of the base material (flexible substrate material with metal foil) is 25 wt% or more and 35 wt% or less. When the residual solvent concentration is less than 25% by weight, the resin on the surface of the metal foil accelerates the transition from the resin to the polyimide in the post-conveying step during curing, and the dimensional change rate increases. On the other hand, if the residual solvent concentration exceeds 35% by weight, the resin may adhere to the initial roll in an apparatus that performs high-temperature treatment.

  The temperature in the pre-transport process is preferably less than 300 ° C, more preferably 120 ° C or more and less than 300 ° C, and particularly preferably 150 ° C or more and 200 ° C or less. If the temperature is 120 ° C. or lower, the initial roll may be covered with resin during conveyance. Moreover, at 300 degreeC or more, a dimensional change rate becomes large.

  The temperature in the post-conveying process is preferably 300 ° C. or higher, more preferably 300 ° C. or higher and 500 ° C. or lower, and particularly preferably 400 ° C. or higher and lower than 500 ° C. If it is less than 300 ° C., the reaction does not proceed sufficiently, and if it exceeds 500 ° C., there is a risk of thermal decomposition of the polyimide.

  The rate of dimensional change refers to the degree to which the dimensional change of a circuit-forming film, an insulating substrate, etc. is not easily affected by processes such as high-temperature and high-humidity processing in the manufacturing process and changes in storage environment. For this reason, since the stability of the dimensional change rate before and after the process is required, it is preferable that the dimensional change rate is low and does not change before and after the process. The flexible substrate material with metal foil having the above-described excellent characteristics can be formed through a manufacturing process in which a resin composition containing a resin film precursor is applied on a metal foil, dried and cured.

  The resin film with metal foil is not particularly limited as long as it is an insulating film, but at least one kind is preferably a polyimide resin or a polyimide precursor from the viewpoint of mechanical characteristics and electrical characteristics. Polyamic acid is converted to polyimide during the manufacturing process. Additive components such as epoxy compounds, acrylic compounds, diisocyanate compounds, phenol compounds, etc., fillers, particles, coloring materials, leveling agents, coupling agents, etc. are optionally mixed as a resin composition containing a resin film precursor. Although it is also possible to add a hardening component and an additional component more than content of a polyimide resin, there exists a tendency for a characteristic to fall.

  Preferably, the polyimide finally formed on the metal foil is represented by the following general formula (1)

(Here, R ₁ is a residue obtained by removing the amino group of the aromatic diamine and the dianate group of the diisocyanate, and R ₂ is a residue obtained by removing the carboxylic acid induction part of the aromatic tetracarboxylic acid derivative.) A polymer having a repeating unit represented by the following general formula (2):

(Here, R ₁ is a residue obtained by removing the amino group of the aromatic diamine and the dianate group of the diisocyanate, and R ₂ is a residue obtained by removing the carboxylic acid induction part of the aromatic tetracarboxylic acid derivative.) It is a polymer which has a repeating unit represented by these.

  The polyimide precursor can be synthesized by reacting an aromatic tetracarboxylic acid derivative with a diamine and / or diisocyanate.

  Examples of the diamine include p, m, o-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 2,4-diaminoxylene, diaminodiurene 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, benzidine, 4,4′-diaminoterphenyl, 4,4 ′ ″-diaminoquaterphenyl, 4,4′-diaminodiphenylmethane, 1,2-bis (anilino) ethane, 4,4′-diaminodiphenyl ether, diaminodiphenyl sulfone, 2,2-bis (p-aminophenyl) propane, 2,2-bis (p-aminophenyl) hexafluoropropane, 2,6-diaminonaphthalene, 3,3-dimethylbenzidine, 3,3′-dimethyl-4 , 4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-di Minodiphenylmethane, diaminotoluene, diaminobenzotrifluoride, 1,4-bis (p-aminophenoxy) benzene, 4,4'-bis (p-aminophenoxy) biphenyl, 2,2'-bis {4- (p- Aminophenoxy) phenyl} propane, diaminoanthraquinone, 4,4′-bis (3-aminophenoxyphenyl) diphenylsulfone, 1,3-bis (anilino) hexafluoropropane, 1,4-bis (anilino) octafluorobutane, 1,5-bis (anilino) decafluoropentane, 1,7-bis (anilino) decafluorobutane, 2,2-bis {4- (p-aminophenoxy) phenyl} hexafluoropropane, 2,2-bis { 4- (3-aminophenoxy) phenyl} hexafluoropropane, 2,2 Bis {4- (2-aminophenoxy) phenyl} hexafluoropropane, 2,2-bis {4- (4-aminophenoxy) -3,5-dimethylphenyl} hexafluoropropane, 2,2-bis {4- (4-Aminophenoxy) -3,5-ditrifluoromethylphenyl} hexafluoropropane, p-bis (4-amino-2-trifluoromethylphenoxy) benzene, 4,4′-bis (4-amino-2-) Trifluoromethylphenoxy) biphenyl, 4,4′-bis (4-amino-3-trifluoromethylphenoxy) biphenyl, 4,4′-bis (4-amino-2-trifluoromethylphenoxy) diphenylsulfone, 4, 4′-bis (3-amino-5-trifluoromethylphenoxy) diphenylsulfone, 2,2-bis {4- ( 4-amino-3-trifluoromethylphenoxy) phenyl} hexafluoropropane, the following general formula (3)

(R ₃ is a monovalent organic group, R ₄ is a divalent organic group, and n is an integer greater than 1)
And diisocyanates obtained by reacting these diamines with phosgene, such as tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, diphenyl ether diisocyanate, phenylene-1, There are aromatic diisocyanates such as 3-diisocyanate.

  Moreover, the following are mentioned as tetracarboxylic acid and its derivative (s). The tetracarboxylic acid is exemplified here, but of course, esterified products, acid anhydrides and salt oxides thereof can also be used. Pyromellitic acid, 2,3,3 ′, 4′-tetracarboxydiphenyl, 3,3 ′, 4,4′-tetracarboxydiphenyl, 3,3 ′, 4,4′-tetracarboxydiphenyl ether, 2,3 3 ′, 4′-tetracarboxydiphenyl ether, 3,3 ′, 4,4′-tetracarboxybenzophenone, 2,3,3 ′, 4′-tetracarboxybenzophenone, 2,3,6,7-tetracarboxynaphthalene, 1,4,5,7-tetracarboxynaphthalene, 1,2,5,6-tetracarboxynaphthalene, 3,3 ′, 4,4′-tetracarboxydiphenylmethane, 2,2-bis (3,4-dicarboxy) Phenyl) propane, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane, 3,3 ′, 4,4′-tetracar Xydiphenylsulfone, 3,4,9,10-tetracarboxyperylene, 2,2-bis {4- (3,4-dicarboxyphenoxy) phenyl} propane, 2,2-bis {4- (3,4- Dicarboxyphenoxy) phenyl} hexafluoropropane, butanetetracarboxylic acid, cyclopentanetetracarboxylic acid and the like.

  The polyamic acid or polyimide solution synthesized by the above combination does not need to have a single composition, and may be a mixture or cocondensation of two or more kinds. At that time, it is desirable that the cured resin film has a relative dielectric constant of 5 GHz or less and a linear thermal expansion coefficient of 25 or less. When this value is exceeded, there exists a tendency which does not show sufficient physical property as a flexible substrate material.

  Furthermore, the ratio of the number of moles of diamine and diisocyanate to the number of moles of the aromatic tetracarboxylic acid derivative is desirably 0.95 to 1.05, and if it is outside this range, the molecular weight becomes small and sufficient. Film properties cannot be obtained.

  Usually, the synthesis reaction consists of N-methyl-2-pyrrolidone (NNP), N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), dimethyl sulfate, sulfolane, The reaction is performed in a range of 0 to 200 ° C. in a solution of γ-butyrolactone, cresol, phenol, halogenated phenol, cyclohexane, dioxane, or the like.

Further, it can be modified with a compound having a reactive functional group to introduce a crosslinked structure or a ladder structure. For example, there are the following methods.
(I) A pyrrolone ring, an isoindoloquinazolinedione ring, or the like is introduced by modification with a compound represented by the following general formula (4).

(R ₅ is a 2 + x-valent aromatic organic group, Z is a group selected from NH ₂ group, CONH ₂ group, SO ₂ NH ₂ , and OH group, and is ortho-position to the amino group. X is 1 or 2.
(Ii) It is modified with an amine, diamine, dicarboxylic acid, tricarboxylic acid or tetracarboxylic acid derivative having a polymerizable unsaturated bond to form a crosslinked structure upon curing. As the unsaturated bond, maleic acid, nadic acid, tetrahydrophthalic acid, ethynylaniline and the like can be used, but are not limited to the above compounds.

  Examples of the metal conductor foil used in the present invention include copper, aluminum, iron, gold, silver, nickel palladium, chromium, molybdenum and the like, or alloys thereof, and chemical roughening is required to increase the adhesion with polyimide. Mechanical or chemical treatment may be carried out by chemical conversion, corona discharge, sanding, plating, aluminum alcoholate, aluminum chelate, silane coupling agent or the like.

  In the present invention, as a method for forming a polyimide film layer on the metal foil, a solution containing 8 to 40% by weight of polyamic acid or polyimide is discharged from the film-forming slit on the surface of the metal foil and uniformly applied. Examples of the coating method include a roll coater, a comma coater, a knife coater, a doctor blade flow coater, a closed coater, a die coater, and a lip coater.

  For example, the manufacturing process of curing the polyamic acid that is a polyimide precursor is performed at 250 to 550 ° C. in a reducing atmosphere composed of an inert gas not containing oxygen in order to prevent the acid value of the metal foil, from the polyimide precursor to the polyimide resin. Curing is performed. Here, the inert gas atmosphere containing no oxygen is an oxygen concentration of 5% or less in an evacuated container or an atmosphere in which an inert gas and a reducing gas are pressure-purged in a dryer or curing furnace with a small entrance and exit. It is important in terms of quality and safety to sufficiently manage this with an oximeter.

  Examples of the inert gas include helium, neon, argon, nitrogen, metallic glitter, pure gas, and a mixed gas thereof. Nitrogen gas is preferable for handling. An example of the reducing gas is hydrogen gas.

  The reducing atmosphere is preferably a mixed gas of nitrogen gas and 0.1% to 4% by volume of hydrogen gas. If the hydrogen gas is less than 0.1% by volume, the reducing gas has no effect and 4% by volume. If it exceeds, the lower limit of explosion of hydrogen gas in the air is exceeded, which is not preferable for safety.

  By curing in the above reducing atmosphere, oxidation of the polyimide can be prevented, so that a highly reliable film can be obtained. Furthermore, coloring of the film can be prevented, and there is an advantage that workability during processing is improved.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. In addition, the measuring method of the dimensional change rate in an Example and a comparative example is as follows.
(Dimensional change rate)
A flexible substrate material with a metal foil is cut out at a 150 mm square, holes are drilled at four corners using a 0.3 mm drill, and the positions of the holes are measured with a three-dimensional measuring instrument. Thereafter, the metal foil portion of the flexible substrate material with metal foil is etched and dried at 130 ° C. for 30 minutes, and then the positions of the holes opened at the four corners are measured again with a three-dimensional measuring instrument. The dimensional change rate was calculated from the difference between before and after.

(Synthesis example)
While flowing about 300 ml / min of nitrogen into a 60 L stainless steel reaction kettle equipped with a thermocouple, stirrer and nitrogen inlet, 867.8 g of p-phenylenediamine, 1606.9 g of 4,4′-diaminodiphenyl ether and 40 kg of N-methyl-2-pyrrolidone was added and stirred to dissolve the diamine component. While this solution was cooled to 50 ° C. or less with a water jacket, 4722.2 g of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride was gradually added to advance the polymerization reaction, and polyamic acid and N— A viscous polyamic acid varnish containing methyl-2-pyrrolidone was obtained. Thereafter, in order to improve the coating workability, cooking was performed at 80 ° C. until the rotational viscosity of the varnish reached 10 Pa · S.

(Coating example 1)
The polyamic acid varnish obtained in the above synthesis example was applied on the roughened surface of the copper foil to a thickness of 50 μm using a coating machine (comma coater). As the copper foil, a rolled copper foil (trade name “BHY-02B-T” manufactured by Nikko Materials) having a width of 540 mm and a thickness of 12 μm was used. Using a forced air drying oven, the solvent was removed from the polyamic acid varnish applied to the copper foil until the residual solvent amount was 20% by weight to form a resin composition layer containing polyamic acid.

(Coating example 2)
The same procedure as in Application Example 1 was repeated except that the polyamic acid varnish obtained in the above synthesis example was applied to a thickness of 50 μm and the solvent was removed from the polyamic acid varnish applied to the copper foil until the ratio of the solvent reached 50% by weight. Thus, a resin composition layer was formed.

(Coating example 3)
The same procedure as in Application Example 1, except that the polyamic acid varnish obtained in the above synthesis example was applied to a thickness of 50 μm, and the solvent was removed from the polyamic acid varnish applied to the copper foil until the ratio of the solvent reached 70% by weight. Thus, a resin composition layer was formed.

(Examples 1-2, Comparative Examples 1-2)
High temperature treatment of the polyamic acid with copper foil was performed using a far infrared irradiation type heat treatment apparatus. A flexible substrate material with a copper foil was prepared. The residual solvent concentration at this time was 43% by weight.

  Using a coating machine (comma coater), polyamic acid varnish was applied to a thickness of 25 μm on the roughened copper foil surface. A rolled copper foil (BHY-02-BT manufactured by Nikko Materials Co., Ltd.) having a width of 250 mm and a thickness of 12 μm and roughened on one side was used as the copper foil. When coating was performed under standard conditions of a coating temperature of 60 ° C. and a conveyance speed of 10 m / min, a base material having a residual solvent concentration of 43% by weight was obtained. In addition, by appropriately raising the coating temperature and lowering the conveyance speed, those having a residual solvent concentration of 34% by weight, 30% by weight, and 21% by weight, respectively, were prepared and used as substrates for feeding to the conveyance device.

  Moreover, the temperature of the process before conveyance in a heat processing apparatus was 150 degrees C or less, and the temperature of the process before conveyance was 450 degreeC or more. The line speed at this time was 0.3 and 1.0 m / min.

As shown in Tables 1 and 2, Example 1 having a residual solvent concentration Vc of 34% by weight and 30% by weight
No. 2 and No. 2 have a good appearance with no tack regardless of the line speed, and have a low dimensional change rate. On the other hand, in Comparative Example 1 where the residual solvent concentration Vc is 43% by weight, tackiness occurs at a line speed of 1.0 m / min, the appearance is poor, and the dimensional change rate is high. In Comparative Example 2 in which the residual solvent concentration Vc was 21% by weight, the dimensional change rate was high.

Claims (7)

  A process of applying and drying a resin solution on a metal foil, a process of supplying a substrate (a flexible substrate material with a metal foil) obtained by removing a solvent contained in the resin solution to a transport apparatus, and a high-temperature treatment in the transport apparatus A method for producing a flexible substrate material with a metal foil comprising a step of performing a process, wherein a residual solvent concentration (Vc) in a resin of a base material is 25% by weight or more and 35% by weight or less. Material manufacturing method.   The process of performing high-temperature processing in the transport apparatus includes a pre-transport process and a post-transport process, wherein the temperature of the pre-transport process is less than 300 ° C., and the temperature of the post-transport process is 300 ° C. or more. Item 2. A method for producing a flexible substrate material with a metal foil according to Item 1.   The method for producing a flexible substrate material with a metal foil according to claim 1 or 2, wherein the metal foil is a copper foil.   The substrate (flexible substrate material with metal foil) is a resin film with metal foil, The method for producing a flexible substrate material with metal foil according to any one of claims 1 to 3.   The method for producing a flexible substrate material with a metal foil according to claim 4, wherein at least one of the resin components of the resin film is a polyimide resin or a polyimide precursor.   The metal substrate according to any one of claims 1 to 5, wherein the dimensional change rate of the cured product of the flexible substrate material with metal foil is ± 0.10% or less when the line speed fluctuates. A flexible substrate material with a metal foil obtained by using a method for producing a flexible substrate material with a foil.   The flexible laminated board manufactured using the flexible board | substrate material with metal foil of Claim 6.