WO2005068183A1

WO2005068183A1 - Continuous production method for both-sided conductor polyimide laminate

Info

Publication number: WO2005068183A1
Application number: PCT/JP2004/019523
Authority: WO
Inventors: Kazuya Miyamoto; Akira Tokumitsu; Masakazu Ii; Yoshihiro Shigematsu; Ichiro Higasayama; Masahiro Kanno; Yujiro Nakagawa
Original assignee: Nippon Steel Chemical Co., Ltd.
Priority date: 2004-01-16
Filing date: 2004-12-27
Publication date: 2005-07-28
Also published as: TW200602191A; JP3790250B2; CN1906027A; KR20060126561A; CN1906027B; TWI333895B; KR101027203B1; JP2005199615A

Abstract

A method of continuously producing a both-sided conductor polyimide laminate free from defective appearance such as longitudinal wrinkles and stable in quality in a rolled state. The method of continuously producing a both-sided conductor polyimide laminate comprises the step of introducing continuously a one-sided conductor laminate having at least three polyimide resin layers, a base layer, an intermediate main layer and a top layer formed on the conductive metal foil (M1), and a base material consisting of a conductive metal foil (M2) into between a pair of heating press rolls, and laminating and integrating the conductive metal foil (M2)to the top layer by heat press bonding, characterized in that the one-sided conductor laminate and the conductive metal foil (M2) before being introduced into between the heating press rolls are respectively heated preliminarily under an inert gas atmosphere to at least 200°C and up to the glass transition point of the polyimide resin in the top layer and then are brought into contact with the surfaces of the heating press rolls.

Description

Specification

Continuous production method of double-sided conductor polyimide laminate

Technical field

The present invention relates to a continuous production method of a double-sided conductor polyimide laminate suitable for a flexible printed circuit board or the like as a wiring material in response to a demand for miniaturization and light weight of electronic devices, The present invention relates to a continuous production method of a double-sided conductor polyimide laminate which can be stably produced as a roll-wound product without using a shim, and having a variable strength and quality.

Background art

[0002] In recent years, as mobile phones, digital cameras, navigators, and other various electronic devices have become more sophisticated and smaller and lighter, a flexible printed circuit board as an electronic wiring material used for these devices has been developed. There is an increasing demand for smaller and higher-density, multi-layer, finer, and lower-voltage dielectric substrates. Previously, this flexible printed wiring board was manufactured by bonding a polyimide film and a metal foil with an adhesive that can be cured at a low temperature.However, the adhesive layer deteriorates the characteristics of the wiring board, and the polyimide base film is particularly excellent. In addition, there is a problem that heat resistance and flame retardancy are impaired. Another problem with the adhesive layer is that the circuit performance of the wiring deteriorates.

[0003] Specifically, there are problems such as generation of resin smear due to drilling during through-hole processing and a large dimensional change rate during processing of a conductor through-hole. In particular, in the case of a double-sided through-hole structure (such as one formed by bonding a conductor copper foil or the like to both sides of the base film, which is an insulator layer, with an adhesive, etc.), a single-sided flexible print There is a problem that its flexibility is generally lower than that of a substrate. On the other hand, with the high density of ICs and the miniaturization and high density of printed wiring, heat generation increases, and it may be necessary to bond a good thermal conductor. There is also a method of integrating the housing and wiring to make it more compact. In addition, they may require wires with different electrical capacities or require wires that can withstand higher temperatures. Therefore, a flexible acid that is applied directly to a conductor such as copper foil by applying the uncured polyamic acid solution without using an adhesive, and then cured by heating.

RU

[0004] For example, the linear expansion coefficient of the cured product 3. 0 X 10- ⁵ following Jiamin and the polyamic acid which is synthesized by the tetracarboxylic acid anhydride which is cured by heating is applied to the metal foil (e.g., Patent Document 1 ), A resin solution containing a polyamideimide precursor compound having a specific structural unit is applied onto a conductor and imidized (for example, see Patent Document 2), and diamines containing diaminobenzamide or a derivative thereof. And a method in which a precursor solution of an insulating material having a structural unit obtained by a reaction between the polymer and an aromatic tetracarboxylic acid is directly applied onto a conductor and cured (for example, see Patent Document 3). Furthermore, in order to enhance the adhesion to the metal foil, a plurality of polyimide resin solutions are used on the conductor, and the coating and drying are performed multiple times to form a flexible printed wiring with multiple polyimide resin layers. A method of manufacturing a substrate (for example, see Patent Document 4) has also been proposed.

[0005] These flexible printed wiring boards relate to a single-sided structure in which an insulating layer is adhered to only one side of a conductive metal foil by heat curing without using an adhesive. On the other hand, in response to miniaturization and weight reduction of electronic devices, the present inventors first used a single-sided conductor laminate having at least three polyimide layers on one side of a conductive metal foil (M), We propose a method for producing a double-sided conductor polyimide laminate in which a conductive metal foil (M2) is laminated on the polyimide layer under heat and pressure (see Patent Document 5, for example). A large double-sided conductor laminate can form a wiring circuit on both sides of a substrate, and has already been put to practical use for high-density mounting, and has recently been widely used in various fields.

[0006] In the method for manufacturing a double-sided conductor polyimide laminate in Patent Document 5 described above, a specific example of a batch method using a hot press device or the like is disclosed. In such a batch-type hot press device, a combination of a single-sided conductor laminate and a conductive metal foil is simultaneously placed on a pedestal called a hot plate and a plurality of layers are heat-pressed. Normal heating is performed by an electric heater arranged in a hot plate, and the pressure is maintained at a predetermined pressure by pushing up the base by hydraulic pressure and transmitting the pressure to the upper base through the sheet. In such a hot plate, the temperature variation of the heater is large, so that even if various corrections are made, a defective portion may partially occur due to insufficient heating or excessive heating.

[0007] In the case of simultaneously processing a plurality of layers, deterioration of the laminated resin layer is promoted by heating for a long time. This was a very unstable process where the optimum conditions for each product number were narrow. Furthermore, since the laminated base material is repeatedly produced in a batch-type cycle of heating and pressurizing from room temperature to reaching a certain temperature and then cooling, it is necessary to cut the laminated base material not only in terms of production efficiency but also to cut the laminated base material. If foreign matter was caught in at the time or was attached immediately, the appearance of the foreign matter could be transferred to all of the stacked products, causing poor appearance. Therefore, there is a strong demand for a continuous production method of a double-sided conductor polyimide laminate having stable quality.

Patent Document 1: JP-A-62-212140

Patent Document 2: JP-A-63-84188

Patent Document 3: JP-A-63-245988

Patent Document 4: Japanese Patent Publication No. 6-49185

Patent Document 5: JP-A-10-323935

Disclosure of the invention

Problems to be solved by the invention

[0008] Instead of the batch method using a hot press device or the like in the method for manufacturing a double-sided conductor polyimide laminate in Patent Document 5 proposed earlier, the present inventors have performed heating and pressure bonding using a pair of heating press holes. As a result of studying the method for continuous production of a double-sided conductor polyimide laminate, it was found that the transfer conditions of the base material before loading between press rolls were not appropriate. In addition, nearly 10 types of shear, such as lattice wrinkles and converging wrinkles due to thermal expansion and cooling shrinkage during the passage of the base material, are observed, and the roll surface is too high in smoothness. As the degree of adhesion between the material and the roll surface increases, a number of pits (several tens of micron dents) on the product surface, such as complicated seals (hereinafter referred to as trawls) due to wrapping and impurities due to impurities, occur during running. Easy! / It was found that a variety of resolution should do problems.

[0009] Accordingly, an object of the present invention is to provide a double-sided conductive polyimide laminate having a stable appearance without poor appearance such as vertical wrinkles in which a conductive metal layer is laminated on both sides of a polyimide resin layer without an adhesive. An object of the present invention is to provide a method for continuously producing a body. Another object of the present invention is to provide a double-sided conductor having excellent heat resistance and flexibility as a wiring circuit board, particularly having excellent wiring circuit strength strongly demanded by users. Rolled polyimide laminate It is to provide a manufacturing method.

Means for solving the problem

[0010] The present inventors have conducted intensive studies on the above problems, and as a result, pre-heated the single-sided conductor laminate and the conductive metal foil (M) immediately before introduction between the heating press rolls to a specific temperature.

2

The present inventors have found that the above object can be achieved by using a sroll surface which has been roughened to a specific surface roughness (R _a ), and completed the present invention.

[0011] That is, the present invention provides

(1) A single-sided conductor laminate having at least three polyimide resin layers of a base layer, an intermediate main layer, and a top layer on a conductive metal foil (M) and a conductive metal foil (M)

2 is continuously introduced between a pair of heated press rolls, and the conductive metal foil (M)

2 In the method of manufacturing a double-sided conductor polyimide laminate that is laminated and integrated by thermocompression bonding, the single-sided conductor laminate just before introduction between the heating press rolls and the conductive metal foil (M each

2) to 200

A continuous production method of a double-sided conductor polyimide laminate, characterized by contacting the surface of a heated press roll after preheating to a temperature not lower than ° C and not higher than a glass transition point of a polyimide resin of one top layer.

(2) The surface of the pair of press rolls according to the present invention is roughened to an average surface roughness (Ra) of 0.01 to 5 μm, and the press roll surface temperature is reduced in an inert gas atmosphere. 340—3 90. C, it is preferable to heat and press under the conditions of a linear pressure between press rolls of 50 kggcm to 300 kggcm (490 to 2940 NZcm) and a passage time of 2 to 5 seconds.

(3) Whether the single-sided conductor laminate and the conductive metal foil (M) in the present invention are in a roll-wound state

2

It is preferable that the pre-heating is performed in a state where the flatness is increased in a nitrogen atmosphere through a plurality of guide rolls each having a different height of a central axis.

(4) The preheating in the present invention is desirably performed by a guide roll with a built-in heating means disposed at a position where the base material contacts the surface of the heating press roll.

(5) It is desirable that a ceramic film is sprayed on the roll surface in the present invention to form a surface roughness (Ra).

The invention's effect

According to the present invention, the single-sided conductor laminate before introduction between the heated press rolls and the conductive Metal foil (M) at 200 ° C or more under inert gas atmosphere

2 By preheating at a temperature below one glass transition point (preferably 200-350 ° C) and then bringing it into contact with the heated press roll surface, the sudden rise in temperature during thermocompression bonding is reduced, resulting in a double-sided conductor laminate Appearance defects such as vertical streaks on the surface of the glass are prevented. In addition, by maintaining the surface roughness of the heated press roll under specific conditions, the degree of adhesion between the base material and the roll surface is reduced. (Several tens of micron dents on the product surface) are also prevented.

Brief Description of Drawings

FIG. 1 is a schematic flow chart showing a method for producing a double-sided conductor polyimide laminate of the present invention.

FIG. 2 is a schematic longitudinal sectional view showing an example of a guide roll for preheating.

FIG. 3 is a schematic longitudinal sectional view showing an example of a heating press roll.

Explanation of symbols

[0018] 1 Single-sided conductor laminate

2 Conductive metal foil

3 Guide roll

3, Guide roll for preheating

4 Guide roll

4 'guide roll for preheating

5 Heated press roll

6 Heated press roll

7 Double-sided conductor polyimide laminate

8 Guide roll

9 Roll wound products

10 Nitrogen atmosphere treatment chamber

11 Nitrogen sealing mechanism

12 Center axis

13 Rotation support members such as bearings

14 Heating means 17 Heat pipe

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the best mode for carrying out the present invention will be described in detail. First, conductive metal foils (M and M) used in the present invention include copper and aluminum having a thickness of 5 to 150 m.

1 2

Examples thereof include lithium, iron, silver, palladium, nickel, chromium, molybdenum, tungsten, zinc, and alloys thereof, and copper is preferable. In particular, a rolled copper foil product which has been avoided from being used because of its low rigidity and difficulty in controlling the pressure by thermocompression bonding can be suitably used. For the purpose of improving the adhesive strength, the surface may be subjected to siding, nickel plating, copper-zinc alloy plating, or chemical or mechanical surface treatment with aluminum alcoholate, aluminum chelate, silane coupling agent, or the like. .

[0020] Here, a single-sided conductor laminate in which a polyimide resin is heat-cured and adhered as an insulating layer without adhesive to one surface of a conductive metal foil (M) that is strong is described in Patent Document 1-14. The publicly known ones disclosed in and 5 can be used. The polyimide resin used as the insulator layer is a general term for a resin having an imide ring structure, and examples thereof include polyimide, polyamideimide, and polyesterimide. Examples of the polyimide resin layer include, but are not particularly limited to, those having low thermal expansion as described in Patent Documents 14 to 14, and thermoplastic polyimides which melt or soften when heated. The insulating layer is composed of a base layer made of a thermoplastic polyimide resin obtained by heating and curing a polyimide precursor resin solution described in Patent Document 5, and a low thermal expansion polyimide resin. An intermediate main layer and a top layer made of a thermoplastic polyimide resin are preferably composed of at least three polyimide resin layers.

[0021] The low thermal expansion polyimide榭脂forming here the intermediate main layer, the heat resistance of the linear expansion coefficient of ^{30 X 10- 6 (1Z ° C} ) or less preferred tool film, excellent in flexibility It should have good performance. Here, the coefficient of linear expansion was determined using a sample that had completed the imidization reaction, heated to 250 ° C using a thermomechanical analyzer (TMA), cooled at a rate of 10 ° CZ, 240-100 The average linear expansion coefficient in the range of ° C was determined. As a specific example of the low thermal expansion polyimide resin having such properties, a polyimide resin having a unit structure represented by the following general formula (I) described in Patent Document 5 is desired. Good

[0022] [Formula 1]

(However, in the formula, R—R

14 represents a lower alkyl group, a lower alkoxy group, a halogen group or hydrogen)

The thermoplastic polyimide resin used for the base layer and the top layer may have any structure as long as its glass transition point temperature is 350 ° C. or lower. It is preferable that the adhesive strength at the interface is sufficient when pressed under heat and pressure. The thermoplastic polyimide resin as used herein includes those which can be adhered by pressure so that they do not necessarily show sufficient fluidity in a normal state above the glass transition point. Specific examples of the thermoplastic polyimide resin having such properties include those having a unit structure represented by the following general formula (II) or general formula (III) described in Patent Document 5 described above.

[0024] [Formula 2]

(1)

(However, in the formula, 8 is a divalent aromatic group having 12 or more carbon atoms.)

[0025]

(In the formula, Ar is a divalent aromatic group having 12 or more carbon atoms.)

2

Here, specific examples of the divalent aromatic group Ar or Ar include, for example,

1 2 [0027] [Formula 4]

■ -0-,,--^

0-

CH3 CH ₃ or the like can be mentioned, preferably,

[0028]

It is.

[0029] Further, as a method for producing a single-sided conductor laminate, a curing agent such as a known acid anhydride-based amine-based curing agent is added to a polyimide precursor solution or a polyimide solution as described in Patent Document 5 above. Various additives and catalysts such as a silane coupling agent, a titanate coupling agent, an adhesion-imparting agent such as an epoxy conjugate, and a flexibility-imparting agent such as rubber are added to the conductive metal foil (M). And then heat cured by heat treatment to obtain a single-sided conductor laminate. The single-sided conductor laminate has a conductive metal foil (M) as a base layer, a thermoplastic polyimide resin layer as a base layer, an intermediate main layer as a low thermal expansion polyimide resin layer, and a top layer (outermost surface layer). It is preferable that a thermoplastic polyimide resin layer is laminated as ()). Here, when the intermediate main layer does not include a low thermal expansion polyimide resin layer, the single-sided conductor laminate obtained in the heat curing step has a large warp and curl, and the workability in the subsequent steps is reduced. Significantly reduced. If the top layer (outermost layer) does not contain a thermoplastic polyimide resin layer, the adhesive force by thermocompression bonding with the conductive metal foil in the thermocompression bonding roll process will not be sufficiently exhibited. It is not preferred.

At this time, the ratio (t Zt) of the thickness of the low thermal expansion polyimide resin layer to the thickness t of the thermoplastic polyimide resin layer is in the range of 2-100, preferably 5-20. Good range. This thickness

2 1 2

When the ratio (t Zt) is smaller than 2, the thermal expansion coefficient of the entire polyimide resin layer is lower than that of metal foil.

1 2

, The warpage or curl of the single-sided conductor laminate obtained in the first step is increased, and the workability in the next second step is significantly reduced. In addition, when the thickness ratio (t Zt) of the thermoplastic polyimide-based resin layer exceeds the loo, it becomes too large.

2 1 2

In some cases, the adhesive force by the thermocompression bonding in the second step is not sufficiently exhibited.

[0031] The application of the plurality of polyimide resins on the conductive metal foil (M) can be performed in the form of the resin solution, and is preferably described in Patent Documents 4 and 5 described above. After the simultaneous or sequential application of a plurality of precursor solutions or the desolvation treatment at a temperature lower than the imide ring-closing temperature in the form of the precursor solution, the heat conversion of the precursor to polyimide is performed simultaneously. It is preferred to do so. If another polyimide-based precursor solution is applied on the layer completely converted to polyimide and heat-treated to close the imide ring, the adhesion between the polyimide-based resin layers may not be fully exhibited. This causes the quality of the double-sided laminate of the product to deteriorate.

[0032] As a method of applying a polyimide resin solution or a precursor solution thereof (polyamic acid solution) on the conductive metal foil (M), for example, a knife coater, a die coater, a roll coater, a curtain coater, or the like is used. The method can be carried out by a known method, particularly when a thick coating is performed, a die coater or a knife coater is suitable. The polymer concentration of the polyimide-based precursor solution used for coating is usually 5 to 30% by weight, preferably 10 to 20% by weight, depending on the degree of polymerization of the polymer. If the polymer concentration is lower than 5% by weight, a single coating cannot provide a sufficient film thickness, and if the polymer concentration is higher than 30% by weight, the solution viscosity becomes too high and coating becomes difficult.

[0033] The polyamic acid solution applied to the conductive metal foil to a uniform thickness is then subjected to a heat treatment to remove the solvent and further close the imide ring. In this case, if the heat treatment is rapidly performed at a high temperature, a skin layer is formed on the resin surface, and the solvent hardly evaporates or foams. Therefore, it is desirable to perform the heat treatment while gradually increasing the temperature from a low temperature to a high temperature. . In this case, the final heat treatment temperature is usually preferably 300 to 400 ° C. The solution gradually starts to occur, and at 300 ° C or lower, the polyimide film does not sufficiently align on the conductive metal foil, and a single-sided conductor laminate having good flatness cannot be obtained. The overall thickness of the polyimide resin layer as an insulator thus formed is usually 10 to 150 m.

Hereinafter, a detailed description will be given with reference to the drawings. FIG. 1 shows a single-sided conductor laminate of the present invention and a conductive metal foil (M) introduced between a pair of press rolls, and laminated by heating and pressing.

2

It is a schematic flow which shows the manufacturing method of a surface conductor polyimide laminated body. FIG. 2 is a schematic longitudinal sectional view showing an example of a guide roll for preheating. FIG. 3 is a schematic longitudinal sectional view showing an example of a press roll.

In FIG. 1, a single-sided conductor laminate 1 in which an insulating layer made of a polyimide resin is adhered to one surface of the above-described conductive metal foil (M) by heating and curing, and a conductive metal foil (M) 2 And together

2

The roll-winding state force is also continuously drawn out, and after a plurality of guide rolls 3, 3 ′, 4, 4 ′, etc., with different center axis heights, preheating is performed in a state where the flatness is increased, then Heating The conductive metal foil (M) is heated and pressed onto the top layer of the single-sided conductor laminate 1 by passing the pressure point between the press rolls in contact with the surfaces of the press rolls 5 and 6.

2

After forming the double-sided conductor polyimide laminate 7 that has been laminated and integrated, it is pre-cooled by a cooling means c such as spraying an inert gas for cooling as appropriate, and then it is passed through a plurality of guide rolls 8 and 8 'in the outside air. The rolled product 9 is further cooled.

[0036] Here, the plurality of guide rolls 3, 3, 4, 4, 8, 8, etc. and the pair of heating press rolls 5, 6 are at atmospheric pressure or higher in order to prevent irritation of the conductive metal foil. It is desirable that the sealing mechanism (labyrinth seal) 11 be provided in the processing chamber 10 held in an atmosphere of an inert gas such as nitrogen gas, and provided at the base material inlet and the laminate outlet. Here, the single-sided conductor laminate 1 and the conductive metal foil (M) 2 from which the roll winding state force is also continuously drawn are shown in the drawing.

2

However, before being introduced into the processing chamber 10, it is desirable to enhance the flatness under tension by passing through a plurality of guide rolls each having a different center axis height. Processing room 1

Although not shown, the double-sided conductor polyimide laminate after being pulled out from 0 is also passed through under tension by a plurality of guide rolls with different center axis heights in the open air before being made into a rolled product 9. It is desirable to further lower the surface temperature.

[0037] In particular, as means for preheating in a state where planarity is enhanced in the present invention, a heating step is used. Less roll 5.6 Force to make guide rolls 3, (4,) just before heating roll with built-in heating means or Heating lamp or heater that emits radiant energy just before heating press roll h or h

Preheating may be performed by installing 12 or the like, or both preheating means may be used in combination. An example of a particularly preferred type of preheating guide roll with a built-in heating means will now be described with reference to FIG. In FIG. 2, a guide roll 3 ′ (4 ′) has a rotation support member 13 such as a bearing in which the outer periphery of the cavity and a central axis 12 from which both ends of the cavity also protrude are disposed inside both ends of the outer periphery of the roll. And the roll outer periphery is freely rotated around the central axis 12 by the rotation support member 13.

[0038] Heating control means 14 by radiant heat selected from a heating coil by dielectric heating, an infrared heater, a resistance heating coil, and the like are appropriately divided or integrated and fixed to a central axis 12 inside the roll. The radiant heat energy applied to the inner wall surface of the roll is controlled by changing the value of the current flowing to the roll. In the vicinity of the outer surface of the roll, a jacket or heat pipe filled with an organic heat medium having good heat conductivity to uniformly heat the surface temperature with radiant heat energy irradiated from the heating control means is used. The conductive element 17 is embedded and arranged. The strong heat pipe is instantaneously transmitted to the entire outer surface of the roll by heat transfer of the heating means 14 of the center shaft 12 described above, so that an axial temperature difference with high surface temperature accuracy hardly occurs.

Here, the single-sided conductor laminate 1 and the conductive metal foil (M) 2 before introduction between the heating press rolls

2 The preheating temperature is preferably 200 ° C. or higher and a temperature lower than the glass transition point of the thermoplastic polyimide resin as the top layer resin, preferably 200 to 350 ° C. It is desirable that the temperature of the outer surface of the preheating hole be monitored by a temperature sensor embedded in the surface of the roll, and the current value supplied to the heating control means 14 be controlled so as to always maintain a predetermined temperature. If preheating is not performed, or if the preheating temperature is 200 ° C or less, the temperature is extremely thin! It is not preferable because a large number of vertical stripes, horizontal stripes and converging wrinkles are generated on the surface, which leads to poor appearance and poor adhesiveness. If the temperature is higher than the glass transition point, the polyimide resin deteriorates, which is not preferable.

Next, as shown in FIG. 3, the pair of heating presses 5 (6) are structurally structurally similar to the heating press described in FIG. The same as the guide roll 3 '(4') with built-in means and the same reference numerals as those shown in FIG. 2 have the same meanings as those described in FIG. 2, but have a larger diameter and a heating means. It is divided into three parts: 14, 15, and 16 and is different from that in that it is forcibly rotated by a stirring power mechanism (not shown). Near the outer surface of the press roll, there is provided a means for uniformizing the surface temperature by embedding a heat conductive element 17 called a jacket or a heat pipe filled with an organic heat medium having good heat conductivity. . The temperature of the outer surface of the press roll is preferably controlled to a temperature not lower than the glass transition point of the thermoplastic polyimide resin, and more preferably to a set value in the range of 360 to 390 ° C. It is desirable that the temperature of the outer surface of the press roll that is strong be monitored by a temperature sensor embedded in the roll surface, and the current value supplied to the heating means 14, 15, 16 be controlled.

The pair of heated press rolls 5 and 6 hold at least one press roll (not shown) arranged vertically on both sides of the center shaft 12 under a nitrogen atmosphere, and pressurize the press roll to a predetermined position. Alternatively, the gap is adjusted by moving the gears by pressurizing means using gears, so that the optimal pressing force is transmitted from the press roll cap to the base materials 1 and 2 to be introduced. In this case, the line pressure between the heating press rolls should be 50-500KgZcm (490N / cm-4900N / cm), preferably 100-300KgZcm (980NZcm-2940NZcm), and the heat and pressure should be 2-5 seconds. Is desirable.

[0042] Further, a pair of heated press rolls to be used is used in a roughened state in which the average surface roughness (Ra) of the press roll is 0.01 to 5 m, preferably 0.1 to 3 m. Is desirable. If the surface roughness (R _a ) of the press roll is 0.01 μm or less, the double-sided conductor polyimide laminate coming out from between the heating rolls will cause a sticking due to the roll adhesion, resulting in a seam during running or copper. Inevitably pits (dents or dents of several tens of microns) caused by the adhesion of foreign substances such as foil powder are unavoidable. On the other hand, when the thickness is 5 μm or more, the unevenness of the roll surface is transferred to the surface of the laminate, which is not preferable. The roughened surface of the roll can be adjusted by spraying a ceramic coating. The surface roughness (Ra) is determined with a stylus-type surface roughness meter using a diamond needle.

In FIG. 1, a double-sided conductor polyimide laminate 7 in which a conductive metal foil (M) is laminated and integrated by heating and pressure bonding on the top layer of the single-sided conductor laminate 1 by heating press rolls 5 and 6 is formed. After the formation, it is desirable to perform pre-cooling by cooling means C such as blowing inert gas for cooling, but the cooling temperature by cooling means C

7 is unfavorable because warpage occurs. Therefore, at 200 ° C. or higher, which is the same as the preheating temperature described above, a temperature below the glass transition point of the thermoplastic polyimide resin as the top layer resin, preferably 200 ° C. 300 ^o C force S desired ヽ.

[0044] The double-sided conductor type polyimide laminate obtained in the present invention has a conductive metal layer as a conductor on both sides of a polyimide resin layer as an insulator, and has only a good appearance and no occurrence of shiny. Is a roll-wound product that does not vary in quality and is used as an electronic wiring material to be used with the advancement of miniaturization and light weight of mobile phones, digital cameras, navigators, and other various electronic devices that are becoming more sophisticated. It is suitable.

Example

Hereinafter, embodiments of the present invention will be specifically described based on examples and comparative examples.

In the following Examples and Comparative Examples, the coefficient of linear expansion, the curl of a single-sided copper-clad product, and the adhesive force were measured by the following methods.

[0046] That is, the coefficient of linear expansion was measured by using a thermomechanical analyzer (TMA100) manufactured by Seiko Denshi Kogyo Co., Ltd. and then cooled at a rate of 10 ° CZ after increasing the temperature to 250 ° C. The average linear expansion coefficient during C was calculated and obtained. As for the curl of the single-sided copper-clad product, the extreme radius of the copper-clad product having dimensions of 100 mm × 100 mm after imidization by heat treatment was measured.

[0047] The adhesive strength of a single-sided copper-clad product was measured according to JIS C5016: 7.1, using a pattern with a conductor width of 3mm, and peeling the copper foil in the 180 ° direction at a speed of 50mmZ. It was obtained as a value.

[0048] The following abbreviations were used in the examples and comparative examples.

PMDA: pyromellitic anhydride

BTDA: 3, 3 ', 4, 4' benzophenone tetracarboxylic anhydride

DDE: 4,4-diaminodiphenyl ether

MABA: 2, -Methoxy-4,4, -Diaminobenzayulide

(Synthesis example 1) N, N-Dimethylacetamide (2,532 g) was charged into the glass reactor while passing nitrogen, and then 0.5 mol of DDE and 0.5 mol of MABA were charged with stirring, and then completely dissolved. Was. This solution was cooled to 10 ° C, and 1 mol of PMDA was added little by little so that the reaction solution was kept at a temperature of 30 ° C or lower. After the addition was completed, stirring was continued at room temperature for 2 hours. The polymerization reaction was completed. The obtained polyimide precursor solution had a polymer concentration of 15% by weight and an apparent viscosity of 100 MPa's at 25 ° C by a B-type viscometer.

[0050] (Synthesis example 2)

A polyimide precursor solution was prepared in the same manner as in Synthesis Example 1, except that 1 mol of DDE was used as the diamine component and 1 mol of BTDA was used as the acid anhydride component. The obtained polyimide precursor solution had a polymer concentration of 15% by weight and an apparent viscosity of 300 mPa · s at 25 ° C. by a B-type viscometer.

(Preparation of Laminate)

The polyimide precursor solution 2 prepared in Synthesis Example 2 was uniformly applied to a roughened surface of a 35 μm roll-shaped electrolytic copper foil (manufactured by Nippon Gould Co., Ltd.) with a thickness of 12 m using a die coater. The solvent was removed by continuous treatment in a hot air drying oven at 120 ° C. Next, the polyimide precursor solution 1 prepared in Synthesis Example 1 was uniformly coated with a thickness of 200 m from above the polyimide precursor layer using a reverse roll coater, and was continuously applied in a hot air drying oven at 120 ° C. After removing the solvent, the polyimide precursor solution 2 prepared in Synthesis Example 2 was evenly applied to a thickness of 15 m, and then heated from 120 ° C to 360 ° C in a hot-air drying oven for 30 minutes. The temperature was raised, heat treatment was performed, and imidization was performed to obtain a single-sided copper-clad product a having a polyimide resin layer having a thickness of 25 μm and having good flatness without warpage or curling. The 180 ° peel strength (JIS C-5016) between the copper foil layer of this single-sided copper clad product a and the polyimide resin layer was 0.8 kgZcm, and the coefficient of thermal expansion of the film after etching was 0.8 kgZcm. was ^{23. 5 X 10- 6 (1Z °} C).

(Example 1)

The resin-coated surface of the copper-clad product with a single-sided insulation layer prepared in the production example and the rolled sheet having a width of 500 mm and the roughened surface of a rolled copper foil having a width of 35 m having the same width as the rolled sheet were prepared. A pair of heated press rolls (outer diameter: 300 mm, width: 800 mm, and naphthalene sealed as a uniform heating means near the surface) were passed through guide rolls under a nitrogen atmosphere. A heat pipe of a ket type is embedded, and a structure in which a dielectric heating coil is built in the center axis of the inside). The hot press was performed under the conditions of a surface temperature of 360 ^° -390 ^° C., a linear pressure between the press opening of 150 ° -170 kg / cm, and a transit time of 2-5 seconds. At this time, the double-sided copper obtained was obtained when the preheating was not performed under the same base material and the same heating press roll conditions, and when the preheating temperature was changed to 150 ° C, 250 ° C, and 340 ° C. Table 1 shows the results of a visual inspection of the surface condition of the upholstered product.

[0053] [Table 1]

(Example 2)

In Example 1 above, the set temperature of the heated press roll surface was set at 360 ° C, the linear pressure between the press rolls was set at 150 kgZcm, the passage time was set at 3 seconds, and there was no preheating of the base material introduced between the heated press rolls.ヽ The surface roughness (Ra) of the heated press roll is 0.01 or less, 0.05, 0.20, 10.0 for both the case and the case where the preheating temperature is 250 ° C and 340 ° C. Table 2 shows the results of a visual inspection of the surface condition of the double-sided copper-clad product obtained when the distance was changed between four steps of m.

[Table 2] Temperature (in) R am) Surface condition of double-sided stretched product

No preheating 0.01 or less defective (shears and pits caused by toray)

0. 05 defective (many vertical stripes and horizontal stripes)

0.20 Failure (many vertical stripes and horizontal stripes)

10.0 Generation of unevenness

250 0.01 or less defective (shears and pits caused by toray)

0.05 Good appearance

0.20 good)

10.0 Generation of unevenness

340 0. 01 or less Bad

0.05 Good appearance

0.20 Good appearance

10.0 Unevenness Industrial applicability

The method for producing a double-sided conductor polyimide laminate of the present invention is a method for continuously producing a double-sided conductor polyimide laminate in a roll-wound state with a stable double-sided conductor polyimide-based laminate having no appearance defects such as vertical wrinkles. It is a manufacturing method with high industrial applicability.

Claims

The scope of the claims

[1] Conductive metal foil (Single-sided conductor laminate with at least three polyimide resin layers of base layer, intermediate main layer, and top layer on M ^ and conductive metal foil (M)

2 is continuously introduced between a pair of heated press rolls, and the conductive metal foil (M) is heated on the top layer.

(2) In the method of manufacturing a double-sided conductor polyimide laminate that is laminated and integrated by pressure bonding, the single-sided conductor laminate and the conductive metal foil (M) before introduction between the heating press rolls are each inert.

2

A continuous production method of a double-sided conductor polyimide laminate, comprising preheating below 200 ° C and below the glass transition temperature of the polyimide resin of one top layer in a gas atmosphere and then contacting the surface of a heated press roll.

[2] The pair of heated press rolls is roughened to an average surface roughness (Ra) of 0.01-5 μm, the surface temperature is 340-390 ° C, and the linear pressure between the press rolls is 50 kg. 2. The method for continuous production of a double-sided conductor polyimide laminate according to claim 1, wherein the thermocompression bonding is performed under the conditions of / cm—300 Kg / cm and a transit time of 2 to 5 seconds.

[3] The single-sided conductor laminate and the conductive metal foil (M) are pulled out of a roll

2

The continuous production method of a double-sided conductor polyimide laminate according to claim 1 or 2, wherein the preheating is performed in a state where the flatness is enhanced by passing through a plurality of guide rolls having different center axis heights.

[4] The method for continuous production of a double-sided conductor polyimide laminate according to any one of [13] to [13], wherein the preheating is performed by a guide roll having a built-in heating means.

[5] The continuous production method of a double-sided conductor polyimide laminate according to claim 2, wherein the ceramic film is sprayed on the roll surface to form a surface roughness (Ra).