JP2005186565A - Manufacturing method for flexible laminated sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a flexible laminated sheet enhanced in appearance and dimensional stability after the removal of a metal foil. <P>SOLUTION: The manufacturing method for the flexible laminated sheet 5 constituted by laminating the metal foil 2 at least on one side of a heat-resistant adhesive film 3 includes a process for thermally laminating the heat-resistant adhesive film 3 and the metal foil 2 between a pair of metal rolls 4 through a protective film 1 and a process for separating the protective film 1, and the heat shrinkage factor of at least one of the heat-resistant adhesive film 3 and the protective film 1 is 0.1% or below at 200°C and 0.4% or below at 300°C. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a flexible laminate having a heat laminating process, and more particularly to a method for producing a flexible laminate having improved appearance and dimensional stability after removal of a metal foil.

  2. Description of the Related Art Conventionally, a flexible laminate in which a metal foil such as a copper foil is bonded to at least one surface of a heat resistant adhesive film such as a polyimide film has been used as a printed board in an electric device such as a mobile phone.

  Conventionally, flexible laminates have been manufactured by bonding a metal foil to a heat-resistant adhesive film with an acrylic or epoxy adhesive. However, in recent years, a flexible laminate produced by thermally laminating a heat-resistant adhesive film and a metal foil without using an acrylic or epoxy adhesive has attracted attention from the viewpoint of heat resistance and durability. Yes.

  The flexible laminate produced by thermal lamination is excellent in heat resistance because it uses a polyimide adhesive layer. In addition, when the flexible laminate is used at the hinge portion of the folding part of the foldable mobile phone, the flexible laminate using the adhesive can be folded about 30,000 times, but by thermal lamination. The flexible laminate can be folded about 100,000 times and is excellent in durability.

  In the manufacturing process of electrical equipment, the flexible laminate undergoes a process that is exposed to high temperatures such as solder reflow. Therefore, from the viewpoint of enhancing the thermal reliability of the flexible laminate, as a heat-resistant adhesive film, the adhesive layer is made of glass. A film having a polyimide heat-fusible layer having a transition temperature (Tg) of 200 ° C. or higher is generally used. Therefore, in order to thermally laminate the heat-resistant adhesive film and the metal foil, it is necessary to thermally laminate at a temperature higher than the Tg of the heat-fusible layer serving as the adhesive layer, for example, 300 ° C. or higher.

  Usually, in a heat laminating machine, a rubber roll is used as at least one of the rolls used for the heat laminating in order to alleviate the pressure non-uniformity during the heat laminating. However, since it is very difficult to heat laminate at a high temperature of 300 ° C. or higher using a rubber roll, a heat laminator having a pair of metal rolls is used. However, when heat laminating using a pair of metal rolls, unlike using a rubber roll, it is difficult to maintain the uniformity of pressure during heat laminating, and there is a rapid temperature change during heat laminating. Therefore, wrinkles are generated in the appearance of the flexible laminate, and there is a problem that the appearance of the flexible laminate is deteriorated. Therefore, a technique for improving the above-mentioned appearance defect by interposing a protective film between a pair of heat rolls when a heat-resistant adhesive film and a metal foil are bonded together by a heat laminator has been proposed (for example, patents). Reference 1). According to this technique, the metal foil and the heat-resistant adhesive film are heat-laminated by interposing the protective film outside the metal foil, so that the heat and pressure are concentrated on the metal foil and the heat-resistant adhesive film by the protective film. In addition to alleviating the above, the expansion and contraction of the metal foil and the heat-resistant adhesive film are suppressed, thereby suppressing the occurrence of appearance defects such as wrinkles.

However, since the polyimide film used for the heat resistant adhesive film and the protective film is subjected to heating and imidization while fixing the ends in order to prevent the film from shrinking, there is residual stress in the film. Such residual stress in the film may cause distortion in the flexible laminate and cause appearance defects such as wrinkles. Also, when forming a wiring and / or circuit by etching at least part of the metal foil of the flexible laminate, the dimensional change rate after removal of the metal foil of the flexible laminate increases due to residual stress in the film. was there.
JP 2001-129918 A

  In order to solve the above problems, an object of the present invention is to provide a method for producing a flexible laminate having improved appearance and dimensional stability after removal of a metal foil.

  The present invention is a method for producing a flexible laminate comprising a metal foil bonded to at least one surface of a heat resistant adhesive film, wherein the heat resistant adhesive film and the metal foil are interposed between a pair of metal rolls through a protective film. Including a step of heat laminating and a step of separating the protective film, and the heat shrinkage ratio of at least one of the heat resistant adhesive film and the protective film is 0.1% or less at 200 ° C. and 0.1% at 300 ° C. It is a manufacturing method of the flexible laminated board characterized by being 4% or less.

In the method for producing a flexible laminate according to the present invention, the linear expansion coefficient α at 200 ° C. to 300 ° C. of at least one of the heat resistant adhesive film and the protective film is the linear expansion at 200 ° C. to 300 ° C. of the metal foil. When the coefficient is α ₀ , it is preferably (α ₀ −10) ppm / ° C. or more and (α ₀ +10) ppm / ° C. or less. Moreover, it is preferable that at least 1 film is a polyimide film among the said heat resistant adhesive film and a protective film. Moreover, it is preferable that at least one film of the heat resistant adhesive film and the protective film is previously heat-treated at 200 to 450 ° C. for 1 to 300 seconds.

  As mentioned above, according to this invention, the manufacturing method of the flexible laminated board which improved the external appearance and the dimensional stability after metal foil removal can be provided.

  Embodiments of the present invention will be described below. In the drawings of the present application, the same reference numerals denote the same or corresponding parts.

  In FIG. 1, the typical schematic of a preferable example of the heat laminating machine used for this invention is shown. This thermal laminating machine includes a pair of metal rolls 4 for thermally laminating the metal foil 2 and the heat-resistant adhesive film 3 via the protective film 1 and a separation roll 6 for separating the protective film 1.

  One method for producing a flexible laminate according to the present invention is as follows. Referring to FIG. 1, in the laminating machine, a heat resistant adhesive film 3 and a metal foil 2 are interposed between a pair of metal rolls 4 via a protective film 1. A laminate 7 is formed in which the protective film 1 is further bonded to the flexible laminate 5 in which the heat-resistant adhesive film 3 and the metal foil 2 are bonded together as shown in the enlarged sectional view of FIG. The laminated body 7 is conveyed by a plurality of rolls while being cooled. Furthermore, the protective film 1 is separated from the laminated body 7 by the separation roll 6, and the flexible laminated board 5 as shown in the expanded sectional view of FIG. 3 is manufactured.

  In the present invention, the heat shrinkage of at least one of the heat resistant adhesive film 3 and the protective film 1 is 0.1% or less at 200 ° C. and 0.4% or less at 300 ° C. By using such a film having a low heat shrinkage rate as at least one of a heat resistant adhesive film and a protective film, the internal stress and strain of the flexible laminate produced during thermal lamination can be reduced, and the appearance and metal of the flexible laminate can be reduced. Dimensional stability after foil removal is improved. From this viewpoint, the heat shrinkage at 200 ° C. is preferably 0.08% or less. The heat shrinkage rate at 300 ° C. is preferably 0.3% or less.

  In the present invention, the heat shrinkage rate of the film refers to the shrinkage rate of the film length after the heat treatment relative to the film length before the film is heat treated at 300 ° C. for 2 hours. Such a heat shrinkage is an index of the residual stress of the film, and the smaller the heat shrinkage, the smaller the residual stress of the film.

In the present embodiment, the linear expansion coefficient at 200 ° C. to 300 ° C. of at least one of the heat resistant adhesive film and the protective film is when the linear expansion coefficient of the metal foil at 200 ° C. to 300 ° C. is α _0. , (Α ₀ −10) ppm / ° C. or more and (α ₀ +10) ppm / ° C. or less is preferable. Since the heat-resistant adhesive film and the protective film are heat-laminated in a state of being in direct contact with the metal foil, the difference between the linear expansion coefficient α of the heat-resistant adhesive film and the protective film and the linear expansion coefficient α ₀ of the metal foil is large. Residual stress and strain of the flexible laminate are increased. From this viewpoint, the linear expansion coefficient of at least one of the heat resistant adhesive film and the protective film is more preferably (α ₀ −5) ppm / ° C. or more and (α ₀ +5) ppm / ° C. or less. As will be described later, when the heat-resistant adhesive film is composed of two or more film layers, the linear expansion coefficient of the heat-resistant adhesive film is a heat-resistant adhesive composed of two or more film layers. The linear expansion coefficient of the whole film shall be said.

  In the present embodiment, the heat-resistant adhesive film and the protective film are not particularly limited, but from the viewpoint of excellent heat resistance and durability, at least one of the heat-resistant adhesive film and the protective film is a polyimide film. Preferably there is.

  In the present embodiment, it is preferable that at least one of the heat resistant adhesive film and the protective film is previously heat-treated at 200 to 450 ° C. for 1 to 300 seconds. By heat treatment under such conditions, a film having a heat shrinkage rate of 0.1% or less at 200 ° C. and 0.4% or less at 300 ° C. can be easily obtained. If the heat treatment temperature is less than 200 ° C. or the heat treatment time is less than 1 second, the residual stress in the film may not be sufficiently reduced. If the heat treatment temperature exceeds 450 ° C. or the heat treatment time is 300 seconds. If it exceeds, the physical properties of the film may be thermally deteriorated.

  Moreover, it is preferable that the tension | tensile_strength concerning at least 1 film among the heat resistant adhesive films and protective films in the case of the said heat processing is as low as possible. Specifically, the tension applied to the film is preferably 0.01 N / cm to 1.5 N / cm, more preferably 0.02 N / cm to 1.0 N / cm, and 0.05 N / cm to 0.8 N / cm. cm is more preferable. If the tension applied to the film is less than 0.01 N / cm, it may cause problems such as sag during film transport, and the film cannot be wound uniformly. If it exceeds 1.5 N / cm, the film is subjected to strong tension. Since it is heated to a high temperature in the state, the heat shrinkage rate may not be improved and may deteriorate.

  As will be described later, when the heat-resistant adhesive film has a thermoplastic film layer, it is necessary to perform heat treatment at a temperature lower than the glass transition temperature of the thermoplastic film. By performing such heat treatment, the residual stress of the heat resistant adhesive film and the protective film is reduced, and the distortion of the flexible laminate is reduced, thereby improving the appearance of the flexible laminate and the dimensional stability after removing the metal foil. .

  By the heat treatment under the above conditions, a film having a heat shrinkage ratio of 0.1% or less at 200 ° C. and 0.4% or less at 300 ° C. can be easily obtained. If the heat treatment temperature is less than 200 ° C. or the heat treatment time is less than 1 second, the residual stress in the film may not be sufficiently reduced. If the heat treatment temperature exceeds 450 ° C. or the heat treatment time is 300 seconds. If it exceeds, the physical properties of the film may be thermally deteriorated.

  Here, as the heat-resistant adhesive film 3, a single-layer film made of a resin showing heat-fusibility, a heat-welding made of a resin showing heat-fusibility on both sides or one side of a core layer not showing heat-fusibility A multi-layer film on which a conductive layer is formed can be used. Here, as the resin exhibiting heat-fusibility, a resin composed of a thermoplastic polyimide component is preferable. For example, thermoplastic polyimide, thermoplastic polyamideimide, thermoplastic polyetherimide, thermoplastic polyesterimide, or the like is used. Can do. Among these, it is particularly preferable to use thermoplastic polyimide and thermoplastic polyesterimide. The core layer that does not exhibit heat-fusibility is not particularly limited as long as it reinforces the strength of the heat-fusible layer made of a resin that exhibits heat-fusibility and retains heat resistance. A thermoplastic polyimide film, an aramid film, a polyether ether ketone film, a polyether sulfone film, a polyarylate film, a polyethylene naphthalate film, or the like can be used. However, it is particularly preferable to use a non-thermoplastic polyimide film from the viewpoint of electrical characteristics (insulating properties).

  In the present invention, the term “thermoplastic” refers to the property of exhibiting plasticity by heating and not exhibiting plasticity by cooling. In particular, it is bonded to a metal foil described later by exhibiting heat-fusibility at the time of thermal lamination. It shall exhibit the characteristics that can be. “Non-thermoplastic” means a property that is not thermosetting but does not exhibit plasticity at the lamination temperature. In addition to a polyimide film having a glass transition temperature higher than the decomposition temperature, the glass transition temperature may be lower than the decomposition temperature. A polyimide film higher than the laminating temperature shall be included.

  Moreover, it is preferable that the tensile elasticity modulus in 25 degreeC of the protective film 1 is 2 GPa or more and 10 GPa or less. If the tensile elastic modulus is less than 2 GPa, the protective film may be stretched by the tension during thermal lamination, and if it exceeds 10 GPa, the protective film becomes hard and the heat applied to the metal foil and heat-resistant adhesive film during thermal lamination The effect of reducing the concentration of pressure may be impaired. From this viewpoint, the tensile elastic modulus at 25 ° C. of the protective film is more preferably 4 GPa or more and 6 GPa or less.

  Moreover, it is preferable that the thickness of the protective film 1 is 75 micrometers or more. When the thickness of the protective film is less than 75 μm, the effect of alleviating the concentration of heat and pressure on the metal foil and the heat-resistant adhesive film during thermal lamination becomes small. From this viewpoint, the thickness of the protective film is more preferably 125 μm or more. On the other hand, the thickness of the protective film is preferably 225 μm or less. When the thickness of the protective film exceeds 225 μm, there is a possibility that troubles such as difficulty in transferring heat from the heat roll during thermal lamination and impaired smoothness of separation of the protective film after thermal lamination.

  Moreover, there is no restriction | limiting in particular as a protective film, A polyimide film etc. other than metal foils, such as copper foil, aluminum foil, and SUS foil, are used preferably. Furthermore, a non-thermoplastic polyimide film is particularly preferably used from the viewpoint of excellent balance between heat resistance and durability.

  As the metal foil 2, for example, a copper foil, a nickel foil, an aluminum foil, or a stainless steel foil is used. The metal foil 2 may be composed of a single layer, or may be composed of a plurality of layers in which a rust prevention layer or a heat-resistant layer (for example, a layer formed by plating treatment of chromium, zinc, nickel, etc.) is formed on the surface. Good. Among these, as the metal foil 2, it is preferable to use a copper foil from the viewpoint of conductivity and cost. Examples of the copper foil include a rolled copper foil, an electrolytic copper foil, and an HTE copper foil. Moreover, since the line width of the circuit pattern in the flexible laminated board used as a printed circuit board can be thinned, so that the thickness of the metal foil 2 is thin, it is preferable that the thickness of the metal foil 2 is 35 micrometers or less, and it is 18 micrometers or less. preferable.

  The heat laminating temperature by the metal roll 4 is preferably 50 ° C. or more higher than the glass transition temperature of the resin showing the heat-fusibility of the heat-resistant adhesive film 3, and in order to increase the heat laminating speed, It is more preferable that the temperature is 100 ° C. or more higher than the glass transition temperature of the heat resistant adhesive film 3. Examples of the heating method for the metal roll 4 include a heat medium circulation method, a hot air heating method, and a dielectric heating method.

  Moreover, it is preferable that the pressure (linear pressure) at the time of the thermal lamination in the metal roll 4 is 49 N / cm or more and 490 N / cm or less. When the linear pressure during thermal lamination is less than 49 N / cm, the linear pressure is too small and the adhesion between the metal foil 2 and the heat resistant adhesive film 3 tends to be weakened. In some cases, the linear pressure is too large, and the flexible laminate 5 is distorted, resulting in a large dimensional change of the flexible laminate 5 after the metal foil 2 is removed. From this viewpoint, the linear pressure during thermal lamination is more preferably 98 N / cm or more and 294 N / cm or less. Examples of the pressurizing method for the metal roll 4 include a hydraulic method, a pneumatic method, and a gap pressure method.

  Moreover, although there is no restriction | limiting in particular in the heat | fever lamination speed | rate, from a viewpoint of productivity improvement, it is preferable that it is 0.5 m / min or more, and it is further more preferable that it is 1 m / min or more.

  Moreover, it is preferable to preheat the protective film 1, the metal foil 2, and the heat resistant adhesive film 3 from the viewpoint of avoiding a rapid temperature rise before heat lamination. Here, the preheating can be performed, for example, by bringing the protective film 1, the metal foil 2, and the heat resistant adhesive film 3 into contact with the heat roll 4.

  Moreover, it is preferable to provide the process of removing the foreign material of the protective film 1, the metal foil 2, and the heat resistant adhesive film 3 before heat lamination. In particular, in order to repeatedly use the protective film 1, it is important to remove foreign matters attached to the protective film 1. Examples of the step of removing the foreign matter include a cleaning process using water or a solvent, and the removal of the foreign matter with an adhesive rubber roll. Especially, the method using an adhesive rubber roll is preferable from the point of simple equipment.

  Furthermore, it is preferable to provide a step of removing static electricity from the protective film 1 and the heat-resistant adhesive film 3 before thermal lamination. As a process of removing static electricity, there is, for example, removal of static electricity by static elimination air.

  Hereinafter, based on an Example and a comparative example, this invention is demonstrated more concretely. In Examples and Comparative Examples, the heat shrinkage rate, the linear expansion coefficient, the appearance, and the dimensional change rate were measured or evaluated as follows.

[Heating shrinkage]
The heat shrinkage rate of the heat resistant adhesive film and the protective film was measured and calculated as follows with reference to JIS C6481. That is, a 200 mm × 200 mm sample was cut out from the film, and holes having a diameter of 1 mm were formed in the four corners of a 150 mm × 150 mm square in this sample. The sample was left in a constant temperature and humidity chamber at 20 ° C. and 60% RH for 12 hours to adjust the humidity, and the distance between the four holes was measured. Thereafter, this sample was heat-treated at 300 ° C. for 2 hours, then cooled in a constant temperature and humidity chamber at 20 ° C. and 60% RH for 30 minutes, and the distance between the four holes was measured in the same manner as before the heat treatment. The heat shrinkage rate was calculated by the following equation (1), where D1 is the measured distance between the holes before the heat treatment, and D2 is the measured distance between the holes after the heat treatment. It shows that a residual stress is so small that the value of this heat shrinkage rate is small.

Heat shrinkage rate (%) = {(D2-D1) / D1} × 100 (1)
[Linear expansion coefficient]
The linear expansion coefficient is the ratio of the relative change amount of the length to the temperature change amount when the object is thermally expanded under a constant pressure. In the present invention, the linear expansion coefficient is expressed in units of ppm / ° C. To do. The linear expansion coefficient of the protective film, the heat-resistant adhesive film, and the metal foil was measured using a thermomechanical analyzer (trade name: TMA (Thermomechanical Analyzer) 120C) manufactured by Seiko Instruments Co. Then, after measuring in a temperature range of 10 ° C to 330 ° C, an average value in a range of 200 ° C to 300 ° C was obtained.

[appearance]
The appearance of the flexible laminate was evaluated visually. In particular, the following evaluation criteria were evaluated by counting the number of wrinkles generated per 1 m ^{2 of} the flexible laminate.
◎ ··· there is no wrinkles ○ wrinkles per ··· 1m ² wrinkles are two or more per × ··· 1m ² 1 or less
[Dimensional change rate]
The dimensional change rate before and after removing the metal foil was measured and calculated as follows with reference to JIS C6481. That is, a 200 mm × 200 mm sample was cut out from the flexible laminate, and holes with a diameter of 1 mm were formed in the four corners of a 150 mm × 150 mm square in this sample. The sample was left in a constant temperature and humidity chamber at 20 ° C. and 60% RH for 12 hours to adjust the humidity, and the distance between the four holes was measured. Next, after removing the metal foil of the flexible laminate by etching, it was left in a temperature-controlled room at 20 ° C. and 60% RH for 24 hours. Thereafter, the distances of the four holes were measured as before the etching process. The dimensional change rate was calculated based on the following equation (2), where D3 was the measured distance of each hole before removing the metal foil, and D4 was the measured distance of each hole after removing the metal foil. It shows that it is excellent in dimensional stability, so that the value of this dimensional change rate is small.

Dimensional change rate (%) = {(D4-D3) / D3} × 100 (2)
(Example 1)
The flexible laminated board was manufactured using the heat laminating machine shown in FIG. First, a thermoplastic polyimide resin layer (glass transition temperature: 240 ° C.) is provided on both surfaces of a core layer made of a non-thermoplastic polyimide film as the heat resistant adhesive film 3, and the heat shrinkage is 0.07% at 300 ° C., 300 A roll around which an adhesive film having a three-layer structure having a linear expansion coefficient of 0.3%, a linear expansion coefficient of 21 ppm / ° C., and a thickness of 25 μm is wound, and the metal foil 2 has a linear expansion coefficient of 19 ppm / ° C. A roll around which copper foil is wound, and the protective film 1 has a heat shrinkage of 0.08% at 200 ° C., 0.2% at 300 ° C., a linear expansion coefficient of 16 ppm / ° C., a tensile modulus of 4 GPa, a thickness A roll around which a non-thermoplastic polyimide film having a thickness of 125 μm was wound was placed in a thermal laminator.

  Next, after these rolls are rotated to remove static electricity, remove foreign matter, and preheat, the adhesive film, copper foil, and non-thermoplastic polyimide film are heat laminated under a pair of metal rolls 4 (temperature: 360). (5 ° C., linear pressure: 196 N / cm, thermal laminating speed: 1.5 m / min), and a laminate having a five-layer structure in which a copper foil and a non-thermoplastic polyimide film are bonded in this order on both sides of the adhesive film 7 was produced.

  And after cooling the laminated body 7 with a some roll, the non-thermoplastic polyimide film was isolate | separated from copper foil with the separation roll 6, and the flexible laminated board 5 was manufactured. Appearance evaluation and dimension measurement of this flexible laminate were performed.

  Furthermore, the copper foil of the said flexible laminated board was removed by the etching process, the dimension after copper foil removal was measured, and the dimensional change rate (MD direction, TD direction) before and behind metal foil (copper foil) removal was computed. These results are shown in Table 1. As shown in Table 1, the flexible laminate of Example 1 had no wrinkles, and the dimensional change rate before and after removing the copper foil was -0.03% in the MD direction and + 0.02% in the TD direction. .

(Example 2)
As a heat-resistant adhesive film, an adhesive having a three-layer structure similar to Example 1 having a heat shrinkage of 0.07% at 200 ° C., 0.3% at 300 ° C., a linear expansion coefficient of 21 ppm / ° C., and a thickness of 25 μm. Non-thermoplastic polyimide with a film and a protective film with a heat shrinkage of 0.1% at 200 ° C., 0.4% at 300 ° C., a linear expansion coefficient of 12 ppm / ° C., a tensile modulus of 6 GPa, and a thickness of 125 μm Except for using a film, a flexible laminate was produced and evaluated for appearance in the same manner as in Example 1, and the dimensional change rate before and after removing the metal foil (copper foil) was calculated. The results are shown in Table 1. The flexible laminate of Example 2 had no wrinkles, and the dimensional change rate before and after removing the copper foil was -0.04% in the MD direction and + 0.03% in the TD direction.

(Example 3)
As a heat-resistant adhesive film, an adhesive having a three-layer structure similar to Example 1 having a heat shrinkage rate of 0.1% at 200 ° C., 0.4% at 300 ° C., a linear expansion coefficient of 22 ppm / ° C., and a thickness of 25 μm. Non-thermoplastic polyimide with a film and a protective film with a heat shrinkage of 0.08% at 200 ° C, 0.2% at 300 ° C, a linear expansion coefficient of 16 ppm / ° C, a tensile modulus of 4 GPa, and a thickness of 125 µm Except for using a film, a flexible laminate was produced and evaluated for appearance in the same manner as in Example 1, and the dimensional change rate before and after removing the metal foil (copper foil) was calculated. The results are shown in Table 1. The flexible laminate of Example 3 had no wrinkles, and the dimensional change rate before and after removing the copper foil was -0.04% in the MD direction and + 0.03% in the TD direction.

Example 4
As a heat-resistant adhesive film, an adhesive having a three-layer structure similar to Example 1 having a heat shrinkage rate of 0.1% at 200 ° C., 0.4% at 300 ° C., a linear expansion coefficient of 22 ppm / ° C., and a thickness of 25 μm. Non-thermoplastic polyimide with a film and a protective film with a heat shrinkage of 0.1% at 200 ° C, 0.4% at 300 ° C, a linear expansion coefficient of 12 ppm / ° C, a tensile modulus of 6 GPa, and a thickness of 125 µm Except for using a film, a flexible laminate was produced and evaluated for appearance in the same manner as in Example 1, and the dimensional change rate before and after removing the metal foil (copper foil) was calculated. The results are shown in Table 1. The flexible laminate of Example 4 had no wrinkles at all, and the dimensional change rate before and after removing the copper foil was −0.04% in the MD direction and + 0.04% in the TD direction.

(Example 5)
As a heat-resistant adhesive film, an adhesive having a three-layer structure similar to Example 1 having a heat shrinkage rate of 0.1% at 200 ° C., 0.4% at 300 ° C., a linear expansion coefficient of 22 ppm / ° C., and a thickness of 25 μm. Non-thermoplastic polyimide with a film and a protective film with a heat shrinkage ratio of 0.15% at 200 ° C, 0.6% at 300 ° C, a linear expansion coefficient of 16 ppm / ° C, a tensile modulus of 6 GPa, and a thickness of 125 µm Except for using a film, a flexible laminate was produced and evaluated for appearance in the same manner as in Example 1, and the dimensional change rate before and after removing the metal foil (copper foil) was calculated. The results are shown in Table 1. The number of wrinkles generated in the flexible laminate of Example 5 was 1 or less per 1 m ² , and the dimensional change rate before and after removing the copper foil was −0.05% in the MD direction and + 0.04% in the TD direction. .

(Example 6)
As a heat-resistant adhesive film, an adhesive having a three-layer structure similar to Example 1 having a heat shrinkage of 0.15% at 200 ° C., 0.6% at 300 ° C., a linear expansion coefficient of 23 ppm / ° C., and a thickness of 25 μm. Non-thermoplastic polyimide with a film and a protective film with a heat shrinkage of 0.1% at 200 ° C., 0.4% at 300 ° C., a linear expansion coefficient of 12 ppm / ° C., a tensile modulus of 6 GPa, and a thickness of 125 μm Except for using a film, a flexible laminate was produced and evaluated for appearance in the same manner as in Example 1, and the dimensional change rate before and after removing the metal foil (copper foil) was calculated. The results are shown in Table 1. The number of wrinkles generated in the flexible laminate of Example 6 was 1 or less per 1 m ² , and the dimensional change rate before and after removing the copper foil was −0.05% in the MD direction and + 0.04% in the TD direction. .

(Comparative Example 1)
As a heat-resistant adhesive film, an adhesive having a three-layer structure similar to Example 1 having a heat shrinkage of 0.15% at 200 ° C., 0.6% at 300 ° C., a linear expansion coefficient of 23 ppm / ° C., and a thickness of 25 μm. Non-thermoplastic polyimide with a film and a protective film with a heat shrinkage ratio of 0.15% at 200 ° C, 0.6% at 300 ° C, a linear expansion coefficient of 16 ppm / ° C, a tensile modulus of 6 GPa, and a thickness of 125 µm Except for using a film, a flexible laminate was produced and evaluated for appearance in the same manner as in Example 1, and the dimensional change rate before and after removing the metal foil (copper foil) was calculated. The results are shown in Table 1. The number of wrinkles generated in the flexible laminate of Comparative Example 1 was 2 or more per 1 m ² , and the dimensional change rate before and after removing the copper foil was −0.10% in the MD direction and + 0.08% in the TD direction. .

As shown in Example 5 and Example 6 of Table 1, the heat shrinkage rate of any one of the heat-resistant adhesive film and the protective film is 0.1% or less at 200 ° C. and 0.4% at 300 ° C. Therefore, the number of wrinkles generated in the flexible laminates of these examples is 1 or less per 1 m ² , and the dimensional change rate before and after removing the copper foil is ± 0 in both the MD direction and the TD direction. It was within the range of 0.05%. Here, the dimensional change rate before and after removal of the copper foil is within a range of ± 0.05% is a range in which no problem occurs in dimensional accuracy even when fine wiring is formed on the flexible laminate.

  Further, as in Examples 1 to 4 of Table 1, the heat shrinkage rate of both the heat-resistant adhesive film and the protective film is 0.1% or less at 200 ° C. and 0.4% or less at 300 ° C. In this case, the flexible laminate had no wrinkles, and the dimensional change rate before and after removing the copper foil was further reduced.

  It should be understood that the embodiments and examples disclosed this time are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  As described above, the present invention can be widely used in a method for producing a flexible laminate for the purpose of improving the appearance and the dimensional stability after removal of the metal foil.

It is the schematic of a preferable example of the heat laminating machine used for this invention. It is a typical expanded sectional view of the layered product used for the present invention. It is a typical expanded sectional view of the flexible laminated board manufactured by this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Protective film, 2 metal foil, 3 heat resistant adhesive film, 4 metal roll, 5 flexible laminated board, 6 separation roll, 7 laminated body.

Claims (4)

A method for producing a flexible laminate comprising a metal foil bonded to at least one surface of a heat-resistant adhesive film,
A step of thermally laminating the heat-resistant adhesive film and the metal foil through a protective film between a pair of metal rolls, and a step of separating the protective film,
Of the heat-resistant adhesive film and the protective film, the heat shrinkage rate of at least one film is 0.1% or less at 200 ° C. and 0.4% or less at 300 ° C. Production method. When the linear expansion coefficient α at 200 ° C. to 300 ° C. of at least one of the heat resistant adhesive film and the protective film is α ₀ , the linear expansion coefficient at 200 ° C. to 300 ° C. of the metal foil is (α _The method for producing a flexible laminate according to claim 1, wherein the production rate is _0-10 ) ppm / ° C or more and (α ₀ +10) ppm / ° C or less.   The method for producing a flexible laminate according to claim 1, wherein at least one of the heat resistant adhesive film and the protective film is a polyimide film.   The at least one film among the heat resistant adhesive film and the protective film is preliminarily heat-treated at 200 ° C to 450 ° C for 1 second to 300 seconds. The manufacturing method of the flexible laminated board of crab.

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