JP3790250B2 - Continuous production method of double-sided conductor polyimide laminate - Google Patents

Description

  The present invention relates to a continuous production method of a double-sided conductor polyimide laminate suitable for a flexible printed circuit board as a wiring material in response to the demand for downsizing and weight reduction of electronic devices, and particularly wrinkle generation using a hot press roll. The present invention relates to a continuous production method for a double-sided conductor polyimide laminate that can be stably produced as a rolled product with no quality variation.

  In recent years, with the progress of miniaturization and weight reduction of highly functional mobile phones, digital cameras, navigators, and other various electronic devices, flexible printed circuit boards (wiring boards) as electronic wiring materials used for them have been developed. There is an increasing demand for smaller, higher density, multilayer, finer, and lower dielectric constants. This flexible printed circuit board was previously manufactured by bonding polyimide film and metal foil together with an adhesive that can be cured at low temperature. However, the adhesive layer has reduced characteristics as a wiring board, especially the superiority of polyimide base film. There is a problem that the heat resistance and flame retardancy are impaired. Another problem with the adhesive layer is that the circuit processability of the wiring is deteriorated.

  Specifically, there are problems such as generation of resin smear due to drilling during through-hole processing and a large dimensional change rate during conductor through-hole processing. In particular, in the case of a double-sided through-hole structure, what is formed by laminating copper foil, etc. of a conductor through an adhesive on both sides of the base film as an insulator layer is compared with a flexible printed board with a single-sided structure. In general, there is a problem that its flexibility is low. On the other hand, heat generation increases with the increase in the density of ICs and the miniaturization and density of printed wiring, and it may be necessary to attach a good heat conductor. There is also a method of integrating the housing and the wiring in order to make it more compact. Furthermore, wiring with different electric capacities may be required, or wiring materials that can withstand higher temperatures may be required. Therefore, various methods for producing a flexible printed board have been proposed in which a polyamic acid solution before curing is directly applied to a conductor such as a copper foil without using an adhesive, and is cured by heating.

For example, a polyamic acid synthesized with a diamine having a linear expansion coefficient of 3.0 × 10 ⁻⁵ or less and a tetracarboxylic acid anhydride applied to a metal foil and cured by heating (for example, see Patent Document 1), A resin solution containing a polyamidoimide precursor compound having a specific structural unit is applied onto a conductor to imidize (see, for example, Patent Document 2), a diamine containing diaminobenzanilide or a derivative thereof, and an aromatic tetracarboxylicsan Examples include those in which a precursor solution of an insulating material having a structural unit obtained by the above reaction is directly applied on a conductor and cured (for example, see Patent Document 3). Further, a method for producing a flexible printed wiring board having a plurality of polyimide resin layers by applying and drying a plurality of times using a plurality of polyimide precursor resin solutions on a conductor in order to improve adhesion to a metal foil (For example, see Patent Document 4) has also been proposed.

These flexible printed wiring boards relate to a single-sided structure in which an insulator layer is bonded to only one side of a conductive metal foil by heat curing without an adhesive. On the other hand, in response to the reduction in size and weight of electronic devices, the present inventors previously used a single-sided conductor laminate having at least three polyimide layers on one side of the conductive metal foil (M ₁ ), The manufacturing method (for example, refer patent document 5) of the double-sided conductor polyimide laminated body which laminates | stacks electroconductive metal foil (M2) on the polyimide layer under heating and pressurization is proposed. Such double-sided conductor laminates can form wiring circuits particularly on both sides of a substrate, have already been put into practical use for high-density mounting, and have been widely used in various fields in recent years.
JP-A-62-212140 JP-A-63-84188 JP-A 63-245988 Japanese Examined Patent Publication No. 6-49185 Japanese Patent Laid-Open No. 10-323935

  In the above-described method for producing a double-sided conductor polyimide laminate in Patent Document 5, a specific example of a batch method using a hot press apparatus or the like is disclosed. In a batch type hot press apparatus or the like, a combination of a single-sided conductor laminate and a conductive metal foil is simultaneously placed on a pedestal called a hot plate and heat-pressed. Normal heating is performed by an electric heater arranged in a hot plate, and the pressure is pushed up by hydraulic pressure to transmit the pressure to the upper base through the seat to maintain a predetermined pressure. In such a hot plate, since the temperature variation of the heater is large, even if various corrections are performed, a defective portion may be partially generated due to insufficient heating or excessive heating.

  Moreover, when processing several layers simultaneously, deterioration of the lamination resin layer was accelerated | stimulated by long-time heating, and it was a very unstable process with the narrow optimal conditions for every product number. Furthermore, since the laminated base material is produced by repeating a batch-type cycle in which it is heated and pressurized from room temperature to reach a certain temperature and then cooled, not only the production efficiency is low, but the laminated base material needs to be cut, At this time, foreign matters are easily caught, and when foreign matters adhere, there are many appearance defects in which the shape of the foreign matter is transferred to all the stacked layers. Therefore, there is a strong demand for a method for producing a double-sided conductor polyimide laminate with stable quality by a continuous method.

  The present inventors, instead of the batch method using the hot press apparatus and the like in the method for producing a double-sided conductor polyimide laminate in Patent Document 5 previously proposed, are double-sided conductor polyimide laminate by thermocompression bonding with a pair of hot press rolls. As a result of studying the continuous production method, the base material is passing through if the transport conditions of the base material before charging between the press rolls, the preheating means and the transport conditions from the outlet of the press roll and the cooling means are not appropriate. Nearly 10 types of wrinkles such as lattice wrinkles and converging wrinkles due to thermal expansion / cooling shrinkage are observed, and when the roll surface is too smooth, the adhesion between the substrate and the roll surface becomes strong. As a result, a lot of complicated wrinkles (hereinafter referred to as “trails”) and pits (scratches of several tens of microns on the product surface) due to impurities are likely to occur during running. It was found that there is a problem to be solved by the people.

  Therefore, the object of the present invention is to continuously manufacture a double-sided conductor polyimide-based laminate having a stable quality without appearance defects such as vertical wrinkles in which conductive metal layers are laminated without using an adhesive on both sides of the polyimide-based resin layer. It is to provide a method. Another object of the present invention is to roll a double-sided conductor polyimide laminate having excellent heat resistance and flexibility as a printed circuit board, which has excellent wiring circuit workability that is particularly demanded by users. It is providing the method of manufacturing in a winding state.

As a result of intensive studies on the above problems, the inventors of the present invention preliminarily heated the single-sided conductor laminate and the conductive metal foil (M ₂ ) immediately before introduction between heated press rolls to a specific temperature, and specified the press roll surface. The present invention was completed by finding that the above-mentioned object was achieved by using a surface roughened surface roughness (Ra).

That is, the present invention
(1) a conductive metal foil (M ₁₎ base layer over the intermediate main layer, single-sided conductor laminate and the conductive metal foil having a polyimide resin layer of at least three layers of the top layer (M ₂₎ and consisting, respectively In the method for producing a double-sided conductor polyimide laminate, the conductive substrate is continuously introduced between a pair of heated press rolls, and the conductive metal foil (M ₂ ) is laminated and integrated on the top layer by thermocompression bonding. The average surface roughness (Ra) is 0 after preheating the single-sided conductor laminate and the conductive metal foil (M ₂ ) immediately before introduction between the rolls to 200 ° C. or more and below the glass transition point of the polyimide resin of the top layer, respectively. It is a continuous production method of a double-sided conductor polyimide laminate, characterized by contacting with the surface of a hot press roll that is roughened to a surface roughness greater than 0.01 μm and 5 μm or less .

(2) The pair of press roll surfaces in the present invention has a press roll surface temperature of 340 to 390 ° C. under an inert gas atmosphere, and a linear pressure between the press rolls of 50 kg / cm to 300 kg / cm (490 to 2940 N / cm). ), It is desirable to heat-press under the conditions of a passage time of 2-5 seconds.

(3) The single-sided conductor laminate and the conductive metal foil (M ₂ ) in the present invention have a flatness in a nitrogen atmosphere through a plurality of guide rolls that are drawn from the roll winding state and have different central axis heights. It is desirable to preheat in an elevated state.

(4) The preheating in the present invention is preferably performed by a guide roll with a built-in heating means disposed at a position where the substrate comes into contact with the heated press roll surface.

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

According to the present invention, the single-sided conductor laminate and the conductive metal foil (M ₂ ) before being introduced between the hot press rolls are each at a temperature of 200 ° C. or more to a glass transition point or less (preferably in an inert gas atmosphere). 200 to 350 ° C.), after preheating at the surface of the heated press roll, the rapid temperature rise at the time of thermocompression bonding is alleviated. As a result, appearance defects such as vertical stripes on the surface of the double-sided conductor laminate are prevented. The Also, 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, so that complicated wrinkles (hereinafter referred to as “trails”) and pits (product surface) due to winding during running Furthermore, the occurrence of dents of several tens of microns is also prevented.

The present invention is described in detail below. First, as the conductive metal foil (M ₁ and M ₂ ) used in the present invention, copper, aluminum, iron, silver, palladium, nickel, chromium, molybdenum, tungsten, zinc, and their thicknesses of 5 to 150 μm are used. An alloy etc. can be mentioned, Preferably it is copper. In particular, a rolled copper foil product, which has low rigidity and is difficult to control pressure by thermocompression bonding, can be suitably used. For the purpose of improving the adhesion, the surface may be subjected to chemical or mechanical surface treatment with siding, nickel plating, copper-zinc alloy plating, aluminum alcoholate, aluminum chelate, silane coupling agent or the like.

The single-sided conductor laminate in which a polyimide resin is heated and cured without an adhesive as an insulator layer on one side of the conductive metal foil (M ₁ ) is disclosed in Patent Documents 1 to 4 and 5 described above. Can be used. The polyimide resin used as the insulator layer is a general term for resins having an imide ring structure, and examples thereof include polyimide, polyamideimide, and polyesterimide. And as a polyimide-type resin layer, the thing of the low thermal expansion as described in the said patent documents 1-4, the thermoplastic polyimide etc. which fuse | melt or soften when heated can be utilized, and it is not specifically limited. However, particularly preferable insulator layers are a base layer made of a thermoplastic polyimide resin obtained by heat curing of a polyimide precursor resin solution described in Patent Document 5, an intermediate main layer made of a low thermal expansion polyimide resin, and a heat What consists of a polyimide-type resin layer of at least three layers of the top layer which consists of a plastic polyimide-type resin is desirable.

Here, the low thermal expansion polyimide resin forming the intermediate main layer preferably has a linear expansion coefficient of 30 × 10 ⁻⁶ (1 / ° C.) or less, and has excellent performance in heat resistance and flexibility of the film. Is good. Here, the linear expansion coefficient is a sample having a sufficiently completed imidation reaction, heated to 250 ° C. using a thermomechanical analyzer (TMA), cooled at a rate of 10 ° C./min, and 240 to 100 ° C. The average linear expansion coefficient in the range is obtained. 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 desirable.

（但し、式中Ｒ₁〜Ｒ₄は低級アルキル基、低級アルコキシ基、ハロゲン基又は水素を示す）

(Wherein R _{1 to} R ₄ represent 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 temperature is 350 ° C. or lower, but preferably under heat and pressure. What has sufficient adhesive strength of the interface when crimping | bonding is good. Here, the thermoplastic polyimide resin does not necessarily have sufficient fluidity in a normal state above the glass transition point, and includes those that can be bonded by pressurization. Specific examples of the thermoplastic polyimide resin having such properties have a unit structure represented by the following general formula (II) or general formula (III) described in Patent Document 5.

（但し、式中Ａｒ₁は２価の芳香族基であってその炭素数が１２以上である。）

（但し、式中Ａｒ₂は２価の芳香族基であってその炭素数が１２以上である。）

(In the formula, Ar ₁ is a divalent aromatic group having 12 or more carbon atoms.)

(In the formula, Ar ₂ is a divalent aromatic group having 12 or more carbon atoms.)

等を挙げることができ、好ましくは、

である。 Here, specific examples of the divalent aromatic group Ar ₁ or Ar ₂ include

Etc., preferably,

It is.

Moreover, as a manufacturing method of a single-sided conductor laminated body, as described in the said patent document 5, hardening agents, such as a well-known acid anhydride type | system | group and an amine type hardening | curing agent, a silane coupling, to a polyimide precursor solution or a polyimide solution. Various additives and catalysts such as adhesives, titanate coupling agents, epoxy compounds, and other adhesives, and rubbers, etc. are added to the conductive metal foil (M ₁ ), followed by heat treatment Can be thermoset to obtain a single-sided conductor laminate. The single-sided conductor laminate is a conductive metal foil (M ₁ ) with a thermoplastic polyimide resin layer as a base layer, a low thermal expansion polyimide resin layer as an intermediate main layer, and a top layer (outermost surface layer) as heat. It is preferable that a plastic polyimide resin layer is laminated. Here, when the intermediate main layer does not include the low thermal expansion polyimide resin layer, warpage and curl of the single-sided conductor laminate obtained in the heat curing step are increased, and workability in the subsequent steps is remarkably reduced. If the top layer (outermost surface layer) does not include a thermoplastic polyimide resin layer, it is not preferable because the adhesive force by thermocompression bonding with the conductive metal foil in the thermocompression-bonding roll process is not sufficiently exhibited.

At that time, the ratio (t ₁ / t ₂ ) between the thickness t _{1 of} the low thermal expansion polyimide resin layer and the thickness t ₂ of the thermoplastic polyimide resin layer is in the range of 2 to 100, preferably 5 to 20. The range is good. If the thickness ratio (t ₁ / t ₂ ) is smaller than 2, the thermal expansion coefficient of the entire polyimide resin layer becomes too high compared to that of the metal foil, and the single-sided conductor laminate obtained in this first step Warpage and curl increase, and workability in the next second step is remarkably reduced. Further, if the thickness t _{2 of the} thermoplastic polyimide resin layer is too small and the ratio of thickness (t ₁ / t ₂ ) increases to exceed 100, the adhesive force by the thermocompression bonding in the second step is sufficient, In some cases, it cannot be used.

The application of the plurality of polyimide resins on the conductive metal foil (M ₁ ) can be performed in the form of the resin solution, but preferably as described in Patent Documents 4 and 5 above. In the form of a precursor solution, it is preferable to perform batch conversion of a plurality of precursor solutions or a solvent removal treatment at a temperature equal to or lower than the imide ring-closing temperature, and then perform heat conversion of the precursors to polyimide in a batch. If another polyimide precursor solution is applied onto the layer that has been completely converted to polyimide and then heat-treated to cause imide ring closure, the adhesive strength between the polyimide resin layers may not be fully demonstrated. This causes the quality of the double-sided laminate to deteriorate.

As a method for coating a polyimide resin solution or a precursor solution (polyamic acid solution) on the conductive metal foil (M ₁ ), for example, a knife coater, a die coater, a roll coater, a curtain coater or the like is used. In particular, when thick coating is performed, a die coater or a knife coater is suitable. The polymer concentration of the polyimide precursor solution used for coating is usually 5 to 30% by weight, preferably 10 to 20% by weight, although it depends on the degree of polymerization of the polymer. When the polymer concentration is lower than 5% by weight, a sufficient film thickness cannot be obtained by one coating, and when the polymer concentration is higher than 30% by weight, the solution viscosity becomes too high and coating becomes difficult.

  The polyamic acid solution applied to the conductive metal foil with a uniform thickness is then subjected to heat treatment to remove the solvent and further imide ring closure. In this case, if the heat treatment is suddenly performed at a high temperature, a skin layer is formed on the resin surface, and the solvent does not easily evaporate or foams. The final heat treatment temperature at this time is usually preferably 300 to 400 ° C., and at 400 ° C. or higher, the thermal decomposition of the polyimide begins to occur gradually. A single-sided conductor laminate with good flatness cannot be obtained without orientation. The total thickness of the polyimide resin layer as an insulator thus formed is usually 10 to 150 μm.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic flow showing a method for producing a double-sided conductor polyimide laminate in which the single-sided conductor laminate of the present invention and a conductive metal foil (M ₂ ) are introduced between a pair of press rolls and laminated and integrated by thermocompression bonding. is there. FIG. 2 is a schematic longitudinal sectional view showing an example of a preheating guide roll. FIG. 3 is a schematic longitudinal sectional view showing an example of a press roll.

In FIG. 1, a single-sided conductor laminate 1 and a conductive metal foil (M ₂ ) 2 in which an insulating layer made of polyimide resin is heat-cured and bonded to one side of the conductive metal foil (M ₁ ) described above are as follows. , After being preheated in a state in which the flatness is improved through a plurality of guide rolls 3, 3 ′, 4, 4 ′, etc., which are continuously drawn from the roll winding state and have different central axis heights, A conductive metal foil (M ₂ ) is laminated on the top layer of the single-sided conductor laminate 1 by thermocompression bonding by passing a pressure point between the press rolls in contact with the surfaces of the heated press rolls 5 and 6. After the integrated double-sided conductor polyimide laminate 7 is formed, it is preliminarily cooled by cooling means c such as blowing an inert gas for cooling as appropriate, and further cooled in the outside air through a plurality of guide rolls 8 and 8 '. While being rolled product 9 .

Here, the plurality of guide rolls 3, 3 ′, 4, 4 ′, 8, 8 ′, etc. and the pair of heated press rolls 5, 6 are not used to prevent oxidation of the conductive metal foil. It is desirable that a seal mechanism (labyrinth seal) 11 is provided in the processing chamber 10 held in an active gas atmosphere and at the base material inlet and the stack outlet. Here, the single-sided conductor laminate 1 and the conductive metal foil (M ₂ ) 2 that are continuously drawn from the roll winding state are not shown, but before being introduced into the processing chamber 10, It is desirable to improve the flatness in a tension state through a plurality of guide rolls having different heights. Further, the double-sided conductor polyimide laminate after being drawn out from the processing chamber 10 is also not shown, but is tensioned by a plurality of guide rolls having different central axis heights in the outside air before being made into a roll-wound product 9. It is desirable to further reduce the surface temperature through the state.

In particular, as a means for preheating in the state in which the flatness is improved in the present invention, the guide roll 3 ′ (4 ′) immediately before the heating press roll 5.6 is of a heating means built-in type, or immediately before the heating press roll. A heating lamp or a heater h ₁ or h ₂ that emits radiant energy may be installed for preliminary heating, or both preliminary heating means may be used in combination. Here, an example of a preheating guide roll with a built-in heating means that is particularly preferable will be described with reference to FIG. In FIG. 2, the guide roll 3 ′ (4 ′) has a rotation support member 13 such as a bearing in which the inner periphery of the hollow and the central shaft 12 protruding from both ends of the cavity are disposed inside the both ends of the outer periphery of the roll. And the outer peripheral part of the roll is configured to freely rotate around the central axis 12 by the rotation support member 13.

  Further, a heating control means 14 by radiant heat selected from a heating coil by dielectric heating, an infrared heater, a resistance heating coil, etc. is fixed to the central axis 12 inside the roll appropriately divided or integrated, and a current flowing to these heating means. The radiant heat energy irradiated to the inner wall surface of the roll is controlled by changing the value. In addition, a heat conduction element called a jacket or heat pipe filled with an organic heat medium having good heat conductivity for uniformly heating the surface temperature with radiant heat energy irradiated from the heating control means in the vicinity of the outer surface of the roll 17 is embedded and arranged. Such a heat pipe is instantaneously transmitted to the entire outer surface of the roll by heat transfer from the heating means 14 of the central shaft 12, so that the surface temperature accuracy is high and the temperature difference in the axial direction hardly occurs.

Here, the preheating temperature of the single-sided conductor laminate 1 and the conductive metal foil (M ₂ ) 2 before being introduced between the heating press rolls is 200 ° C. or higher and the glass transition point of the thermoplastic polyimide resin that is the top layer resin. The following temperature is desirable, preferably 200 to 350 ° C. It is desirable to monitor the outer surface temperature of the preheating roll with a temperature sensor embedded in the roll surface, and to control the current value supplied to the heating control means 14 so as to always maintain a predetermined temperature. When preheating is not performed or when the preheating temperature is 200 ° C. or less, a very thin metal foil is rapidly heated and pressed when passing between heated press rolls, resulting in a large number of vertical stripes and wrinkles on the surface of the laminate. The generation of wrinkles and the like is not preferable because it not only leads to poor appearance but also lowers the adhesiveness. Moreover, since the polyimide resin deteriorates above the glass transition point, it is not preferable.

  Next, as shown in FIG. 3, the pair of heating presses 5 (6) are structurally the same as the heating means built-in type guide roll 3 ′ (4 ′) described in FIG. 2, and are attached in FIG. The same reference numerals have the same meaning as described in FIG. 2, but the diameter is large and the heating means is divided into three parts of 14, 15, 16 and is not shown, but is a stirring power mechanism. The difference is that the structure is forcibly rotated. In the vicinity of the outer surface of the press roll, a means for equalizing the surface temperature is provided by embedding a heat conduction element 17 called a jacket or a heat pipe filled with an organic heat medium having good heat conductivity. The outer surface temperature of the press roll is desirably equal to or higher than the glass transition point of the thermoplastic polyimide resin, and is more preferably controlled to a set value within a range of 360 to 390 ° C. It is desirable to monitor the outer surface temperature of the press roll with a temperature sensor embedded in the roll surface and control the current value supplied to the heating means 14, 15, 16.

  The pair of heating press rolls 5 and 6 are not shown in the figure, but hold at least one press roll arranged on both sides of the central shaft 12 in a nitrogen atmosphere. By moving the pressure by the pressure means and adjusting the gap between the two, the optimum pressurizing force is transmitted from the press roll to the substrates 1 and 2 to be introduced. In this case, the linear pressure between the heated press rolls is 50 to 500 kg / cm (490 N / cm to 4900 N / cm), preferably 100 to 300 kg / cm (980 N / cm to 2940 N / cm), and the passing time is 2 to 5 seconds. It is desirable to thermocompression bond under conditions.

Further, the pair of heated press rolls used has a press roll average surface roughness (Ra) larger than 0.01 μm and 5 μm or less , preferably 0.1 to 3 μm in a roughened state. desirable. When the surface roughness (Ra) of the press roll is 0.01 μm or less, the tray caused by the roll adhesion of the double-sided conductor polyimide laminate that comes out between the heating rolls will generate wrinkles during running, Occurrence of pits (a dent of several tens of microns or dents on the product surface) due to the adhesion of foreign substances is unavoidable. On the other hand, when the thickness is 5 μm or more, unevenness on the roll surface is transferred to the surface of the laminate, which is not preferable. In order to make the roll surface rough within the above range, it can be adjusted by spraying a ceramic film. The surface roughness (Ra) is obtained with a stylus type surface roughness meter using a diamond needle.

In addition, after forming the double-sided conductor polyimide laminate 7 in which the conductive metal foil (M ₂ ) is laminated and integrated on the top layer of the single-sided conductor laminate 1 with the hot press rolls 5 and 6 in FIG. In addition, it is desirable to pre-cool by cooling means c such as blowing an inert gas for cooling, but the cooling temperature by the cooling means c is not preferable because the laminate 7 is warped when cooled too rapidly. A temperature equal to or higher than the preheated temperature of 200 ° C. and lower than the glass transition point of the thermoplastic polyimide resin that is the top layer resin, preferably 200 to 300 ° C.

  The double-sided conductor-type polyimide laminate obtained by the present invention has a conductive metal layer as a conductor on both sides of a polyimide resin layer as an insulator, has a good appearance, is free from wrinkles, and has no quality variation It is a rolled product and is suitable as an electronic wiring material to be used with the progress of miniaturization and weight reduction of highly functional mobile phones, digital cameras, navigators, and other various electronic devices.

  Hereinafter, based on an Example and a comparative example, embodiment of this invention is described concretely. In the following examples and comparative examples, the linear expansion coefficient, the curl of the single-sided copper-clad product, and the adhesive force were measured by the following methods.

  In other words, the linear expansion coefficient is an average linear expansion coefficient between 240 ° C. and 100 ° C. by using a thermomechanical analyzer (TMA100) manufactured by Seiko Denshi Kogyo Co., Ltd. Was calculated. As the curl of a single-sided copper-clad product, the radius of curvature of a copper-clad product having a size of 100 mm × 100 mm after heat treatment and imidization was measured.

  The adhesive strength of a single-sided copper-clad product is the value when the copper foil is peeled off at a speed of 50 mm / min in a 180 ° direction using a pattern with a conductor width of 3 mm in accordance with JIS C5016: Asked.

In the examples and comparative examples, the following abbreviations were used.
PMDA: pyromellitic anhydride BTDA: 3,3 ′, 4,4′-benzophenone tetracarboxylic anhydride DDE: 4,4-diaminodiphenyl ether MABA: 2′-methoxy-4,4′-diaminobenzanilide

(Synthesis Example 1)
2,532 g of N, N-dimethylacetamide was charged into a glass reactor through nitrogen, then 0.5 mol of DDE and 0.5 mol of MABA were charged with stirring, and then completely dissolved. The 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, the mixture was stirred at room temperature for 2 hours to complete the polymerization reaction. I let you. The obtained polyimide precursor solution had a polymer concentration of 15% by weight and an apparent viscosity of 1000 mPa · s at 25 ° C. using a B-type viscometer.

(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 resulting polyimide precursor solution had a polymer concentration of 15% by weight and an apparent viscosity of 300 mPa · s at 25 ° C. using a B-type viscometer.

(Production of laminate)
After 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 Nikko Gould Co., Ltd.) using a die coater with a thickness of 12 μm, hot air at 120 ° C. The solvent was removed by continuous treatment in a drying oven. Next, the polyimide precursor solution 1 prepared in Synthesis Example 1 is coated uniformly with a thickness of 200 μm on the polyimide precursor layer using a reverse roll coater, and continuously processed in a 120 ° C. hot air drying furnace. After the solvent was removed, the polyimide precursor solution 2 prepared in Synthesis Example 2 was uniformly applied with a thickness of 15 μm, and then heat-treated by raising the temperature from 120 ° C. to 360 ° C. in a hot air drying oven over 30 minutes. Imidization was performed to obtain a single-sided copper-clad product a having a flatness having a thickness of 25 μm and no warping or curling. The 180 ° peel strength (JIS C-5016) measured between the copper foil layer and the polyimide resin layer of this single-sided copper-clad product a was 0.8 kg / cm, and the thermal expansion of the film after etching The coefficient was 23.5 × 10 ⁻⁶ (1 / ° C.).

(Example 1)
The roughened surface of the rolled copper foil, which is a 35 μm roll wound sheet having the same width as the resin surface of the 500 mm wide roll wound sheet of the copper-clad product of the single-sided insulator layer prepared in the production example, respectively, under a nitrogen atmosphere Via a guide roll, a pair of heated press rolls (outer diameter is 300 mm, width is 800 mm, a jacket type heat pipe filled with naphthalene as a uniform heating means is embedded near the surface, and the inner central axis is dielectric. After the preheating with the guide roll 3 ′ (4 ′) of the heating means built-in type before being introduced between the heating coil and the heating coil, the surface temperature of the heated press roll is 360 to 390 ° C. and the linear pressure between the press rolls is 150. Thermocompression bonding was performed within a range of ˜170 kg / cm and a passage time of 2 to 5 seconds. At this time, the surface state of the obtained double-sided copper-clad product in the case of preheating under the same base material and the same hot press roll condition and when the preheating temperature is changed to 150 ° C., 250 ° C. and 340 ° C. Table 1 shows the result of visual inspection.

(Example 2)
In Example 1 above, the set temperature of the heated press roll surface is set to 360 ° C., the linear pressure between the press rolls is set to 150 kg / cm, the passing time is set to 3 seconds, and the preliminary heating of the base material introduced between the heated press rolls is performed. For each of the case where there is no surface heating and the preheating temperature of 250 ° C. and 340 ° C., the surface roughness (Ra) of the heated press roll is 0.01 or less, 0.05, 0.20, 10.0 μm in four stages. Table 2 shows the results of visual inspection of the surface state of the double-sided copper-clad product obtained when the distance was changed in between.

It is a schematic flow which shows the manufacturing method of the double-sided conductor polyimide laminated body of this invention. It is a schematic longitudinal cross-sectional view which shows an example of the guide roll for preheating. It is a schematic longitudinal cross-sectional view which shows an example of a heating press roll.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Single-sided conductor laminated body 2 Conductive metal foil 3 Guide roll 3 'Pre-heating guide roll 4 Guide roll 4' Pre-heating guide roll 5 Heating press roll 6 Heating press roll 7 Double-sided conductor polyimide laminated body 8 Guide roll 9 Roll winding Product 10 Nitrogen gas atmosphere treatment chamber 11 Nitrogen seal mechanism 12 Center shaft 13 Rotating support member 14 by bearings, etc. Heating means 17 Heat pipe

Claims (5)

Conductive metal foil (M1) base layer over the intermediate main layer, each of the introduction substrate consisting single-sided conductor laminate and the conductive metal foil (M2) having a polyimide resin layer of at least three layers of the top layer In a method for producing a double-sided conductor polyimide laminate in which a conductive metal foil (M2) is laminated and integrated by thermocompression bonding continuously between a pair of heated press rolls, and before the introduction between the heated press rolls. The average surface roughness (Ra) is 0 after preheating the single-sided conductor laminate and the conductive metal foil (M2) to 200 ° C. or more and below the glass transition point of the polyimide resin of the top layer in an inert gas atmosphere. A method for continuously producing a double-sided conductor polyimide laminate, the method comprising contacting the surface of a heated press roll having a surface roughness greater than 0.01 μm and roughened to 5 μm or less . Three hundred forty to three hundred ninety ° C. The front surface temperature of the pair of heating press rolls, both surfaces of claim 1, thermocompression bonding under the conditions of a linear pressure of 50Kg / cm~300Kg / cm, transit time 2-5 seconds between the press roll A continuous production method of a conductor polyimide laminate.   The said single-sided conductor laminated body and electroconductive metal foil (M2) are preheated in the state which pulled out from the roll winding state, and improved the planarity through the several guide roll from which the height of a central axis each differs. Or the continuous manufacturing method of the double-sided conductor polyimide laminated body of 2.   The method for continuously producing a double-sided conductor polyimide laminate according to any one of claims 1 to 3, wherein the preheating is performed by a guide roll with a built-in heating means. Sided conductor continuous production method of the polyimide laminate according to claim 1, the ceramic coating is sprayed on the roll surface the surface roughness (Ra) is formed.

Images