JP2002361744A - Method for manufacturing heat-resistant flexible laminated sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for preventing shrink marks from being generated when a heat-resistant adhesive film and a metal material are laminated over each other to obtain a flexible laminated sheet, and enhancing the productivity. SOLUTION: This method for manufacturing a heat-resistant flexible laminated sheet comprises the steps to laminate a metallic foil 1 and the heat-resistant adhesive film 2 over each other, using a heat roll laminating device with at least two or more pairs of metal rolls. The heating temperatures of the metal rolls are different from each other. That is, the heat-resistant adhesive film and the metal material are laminated (regularly laminated) by a first-stage metal roll through thermal pressurizing. Next, immediately after the regular lamination at the first stage, the laminate is annealed by a second-stage metal roll and the subsequent metal rolls at lower temperature than the regular laminating temperature. Finally the laminate is gradually cooled while being pressurized so as to reach a temperature near a glass transition temperature for the heat-resistant adhesive film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a laminated board manufactured by a press and heat forming apparatus. In particular, the present invention relates to a method for manufacturing a flexible laminate used for electronic and electrical equipment and the like.

[0002]

2. Description of the Related Art In recent years, weight reduction of electronic products,
As miniaturization and densification have increased, demand for printed circuit boards has increased, and in particular, demand for flexible printed circuit boards formed by forming a copper foil circuit on an insulating film has been increasing. The flexible laminated board has a laminated board in which a metal foil is adhered by a thermosetting adhesive such as a thermosetting resin (hereinafter, referred to as a thermosetting laminated board) and a thermo-fusible type such as a thermoplastic resin. There is a laminate (hereinafter, referred to as a heat-sealing laminate) attached with an adhesive. The thermosetting laminate is made by forming a thermosetting adhesive such as epoxy resin or acrylic resin on both sides of a heat-resistant film such as a polyimide film, bonding it to a metal foil, curing it for a long time, and curing it. Completed and fabricated. In recent years, lead-free solder, which is higher than the conventional melting point, has been used for solder materials due to environmental issues.
Along with this, the heat resistance required for flexible laminates has become more severe, and the epoxy resin of this adhesive layer,
Acrylic resin has become unable to satisfy the heat resistance.

[0003] In order to meet the requirement of heat resistance, a heat-sealing type laminated board using a thermoplastic polyimide resin for an adhesive layer is used. To manufacture a heat-sealed laminate, apply and dry a polyimide resin on one side of a metal material, or apply and dry and cure a polyimide precursor solution, and attach it with a laminating machine with the adhesive surfaces facing each other. A method of manufacturing a flexible laminate on both sides together, or applying and drying a polyimide resin on both sides of a heat-resistant film such as a polyimide film, or applying, drying and curing a polyimide precursor solution to produce an adhesive film, copper There is a method of manufacturing a double-sided flexible laminate by laminating with a laminating apparatus in a configuration of foil / adhesive film / copper foil.

[0004]

In the case of producing the above-mentioned thermosetting laminates, the temperature under pressure and heat molding is almost always 200 ° C. or less. At such a heating temperature, the thermal stress applied to the material to be laminated is small, and appearance defects such as wrinkles during thermal lamination hardly occur.

However, in the case of manufacturing a heat-sealing type laminate, heat-sealing cannot be performed unless pressure heating is performed at a temperature higher than the glass transition temperature (expressed as Tg) of the thermoplastic resin constituting the adhesive layer. . On the other hand, since the laminated board for electronic / electric equipment is heated at a high temperature in the process of mounting components, the thermoplastic resin forming the adhesive layer needs to have a Tg of at least 180 ° C. or higher. Further, a heat lamination temperature of 200 ° C. or more is required for the heat fusion. Lamination at such a high temperature has a problem in that the change in thermal expansion and thermal shrinkage of the material to be laminated becomes large, and the laminated laminate tends to have poor appearance such as wrinkles.

[0006] The cause of wrinkles will be described in more detail.
When laminating a copper foil and a thermoplastic polyimide with a hot roll laminating machine, the copper foil and the thermoplastic polyimide are bonded together by passing between press rolls in a heated and pressurized state of the hot roll laminating machine. At the time of lamination, each material to be laminated is in a state expanded by heat, but since the linear expansion coefficient of thermoplastic polyimide is generally larger than the linear expansion coefficient of copper foil, thermoplastic material expands more in the plane direction than copper foil. Polyimide is heat laminated with copper foil. Immediately after lamination where the pressure is released, the material retains heat, and the temperature is higher than the Tg of the thermoplastic polyimide, so that the thermoplastic polyimide is in a fluid state, and this is rapidly cooled. The thermoplastic polyimide shrinks more in the plane direction than the copper foil, and the resulting laminate has wrinkles in the plane direction.

[0007]

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a method for preventing the generation of wrinkles when laminating a heat-resistant adhesive film and a metal material to produce a flexible laminate and improving the productivity. To provide.

That is, the present inventors add a metal roll having a lower heating temperature than the preceding metal roll to the subsequent stage of the preceding metal roll of the hot roll laminating apparatus, and continuously perform lamination, whereby flexible lamination is performed. They have found that wrinkles that can be formed on the board can be reduced. More specifically, the heat-resistant adhesive film and the metal material are heated and pressed by the first-stage metal roll (also referred to as the present laminate roll) to be laminated. At this time, the heat-resistant adhesive film and the metal material are bonded together in a stretched state by heating the laminate roll. Since each material has a different coefficient of linear expansion, the amount of elongation from room temperature is different, and the materials are bonded together in that state. Wrinkles are formed on the resulting flexible laminate. At this time, immediately after the first-stage main lamination, slow cooling lamination (hereinafter, the second-stage and subsequent metal rolls are also referred to as slow cooling laminating rolls) is performed by the second and subsequent metal rolls at a temperature lower than the main lamination temperature, Finally, it was found that the flexible laminate was not wrinkled by gradually cooling it while pressurizing it to a temperature near Tg of the heat-resistant adhesive film.

Accordingly, a first aspect of the present invention is a method of manufacturing a heat-resistant flexible laminate by laminating a metal foil and a heat-resistant adhesive film using a hot-roll laminating apparatus having at least two pairs of metal rolls. And
A method for producing a heat-resistant flexible laminate, wherein the heating temperatures of the metal rolls are different from each other. A second aspect of the present invention is the method for manufacturing a heat-resistant flexible laminate according to the first aspect, wherein the heating temperature of each metal roll differs by 50 ° C. or more. A third aspect of the present invention is characterized in that the heating temperature of the last metal roll of the hot roll laminating apparatus is equal to or lower than (the glass transition temperature of the heat-resistant adhesive film + 30 ° C.). 2. A method for producing a heat-resistant flexible laminate according to item 1.
A fourth aspect of the present invention is the method for manufacturing a heat-resistant flexible laminate according to any one of the first to third aspects, wherein diameters of two or more pairs of metal rolls of the hot roll laminating apparatus are different. is there. According to a fifth aspect of the present invention, when laminating a metal foil and a heat-resistant adhesive film using the hot roll laminating apparatus, a protective material is disposed between a pressing surface of the apparatus and a material to be laminated. A method for producing a heat-resistant flexible laminate according to any one of claims 1 to 4. Claim 6 is the first of the hot roll laminating apparatus.
Pressing and heating with a metal roll in a step is performed at 200 ° C. or higher, and the protective material and the material to be laminated are lightly adhered to each other, and the protective material is separated from the laminate after cooling. A method for producing a heat-resistant flexible laminate according to any one of claims 1 to 5. Here, the protective material refers to a non-constituent material of the laminate. The protective material and the material to be laminated are in a state of being lightly adhered by passing through the laminating roll. Here, the lightly adhered state refers to a state in which the protective film and the material to be laminated do not peel off each other without applying any force, and refers to a state in which the protective film and the material to be laminated easily peel off by hand.

According to a sixth aspect of the present invention, an adhesive sheet containing 50% by weight or more of a thermoplastic polyimide in an adhesive component is used as the heat-resistant adhesive film.
A method for producing a heat-resistant flexible laminate according to any one of claims 1 to 5. A seventh aspect of the present invention is the method for manufacturing a laminate according to any one of the first to sixth aspects, wherein a copper foil having a thickness of 50 μm or less is used as the metal material. An eighth aspect of the present invention is the method for manufacturing a laminate according to any one of the first to seventh aspects, wherein a polyimide film is used as the protective material.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below.

Although the use of the laminate obtained by the production method of the present invention is not particularly limited, it is mainly used as a flexible laminate for electronic and electric use.

As the heat-resistant adhesive film, a single-layer film made of a resin having a heat-fusing property, a plurality of layers formed by forming a resin layer having a heat-fusing property on both sides of a core layer having no heat-fusing property can be used. Examples include a film in which a base material such as a layer film, paper, and glass cloth is impregnated with a resin having a heat-fusing property. However, when a rigid base material such as a glass cloth is used, the flexibility is deteriorated. As an adhesive film for a board, a single-layer film made of a resin having a heat-fusing property, a multi-layer film formed by forming a resin layer having a heat-fusing property on both sides of a core layer having no heat-fusing property Is preferred. A single-layer film made of a resin having a heat-fusing property, and a multi-layer film formed by forming a resin layer having a heat-fusing property on both sides of a core layer having no heat-fusing property are those having heat resistance. preferable. An adhesive component such as a resin layer having a heat-fusing property in the adhesive film is composed of a thermoplastic polyimide component, for example, a thermoplastic polyimide, a thermoplastic polyamideimide,
Thermoplastic polyetherimide, thermoplastic polyesterimide and the like can be suitably used. Adhesive films containing these heat-resistant thermoplastic resins in an amount of 50% or more of the adhesive component are also preferably used in the present invention. Use of an adhesive film containing a thermosetting resin such as an epoxy resin or an acrylic resin is also possible. preferable. Various additives may be blended in the adhesive film to improve various properties. For example, a filler such as a filler can be used to improve the surface slipperiness of the film, and the type of the filler is not particularly limited, but a filler such as calcium hydrogen phosphate can be used.

The structure of the adhesive film may be a single layer composed of only a heat-fusible adhesive component as long as it has a heat-resistant adhesive layer on the outside. A three-layer film having a heat-fusible adhesive layer on both sides of a core layer having no property is preferred. The non-heat-fusible core layer is not particularly limited as long as it has heat resistance, but a non-thermoplastic polyimide film is preferably used.

The method for producing the adhesive film is not particularly limited. When the adhesive film is composed of a single adhesive layer, it can be formed by a belt casting method, an extrusion method, or the like. In addition, when the configuration of the adhesive film is composed of three layers of an adhesive layer / a core layer having no heat-fusing property / an adhesive layer, both sides of a core layer having no heat-fusing property (for example, a heat-resistant film) are provided. Glue,
A method of producing a three-layer adhesive sheet by applying one side at a time or both sides simultaneously or producing a three-layer adhesive film by arranging a single-layer adhesive film consisting of an adhesive component only on both sides of a heat-resistant film and bonding them together. There is a way to do that. In the method of producing an adhesive film of three layers by applying an adhesive, particularly when a polyimide-based adhesive is used, a method of applying to a heat-resistant film in the state of polyamic acid, and then performing imidation while drying. There is a method of applying a soluble polyimide resin as it is and drying it, and the method of forming the adhesive layer is not particularly limited. In addition, there is also a method of forming a heat-resistant adhesive film at one time by co-extruding the resin of the adhesive layer / the core layer having no heat-fusing property / the adhesive layer.

The metal material is not particularly limited, but in the case of a laminate used for electronic and electric equipment, it is preferable to use a copper foil from the viewpoint of conductivity and cost. The thickness of the metal foil is preferably 50 μm or less, since the thinner the copper foil, the thinner the circuit pattern line width. In particular, a copper foil having a thickness of 35 μm or less has less stiffness than a copper foil having a thickness of more than 30 μm, and is likely to generate wrinkles during thermal lamination. Therefore, the present invention exerts a remarkable effect on a copper foil having a thickness of 35 μm or less. Examples of the type of copper foil include rolled copper foil, electrolytic copper foil, HTE copper foil, and the like. There is no particular limitation, and an adhesive may be applied to these surfaces.

The hot roll laminating apparatus is not particularly limited as long as it is an apparatus for heating a material to be laminated and applying pressure to laminate the material. The heating method is not particularly limited as long as it can be heated at a predetermined temperature,
A heating medium circulation system, a hot air heating system, a dielectric heating system and the like can be given. The heating temperature is preferably 200 ° C. or higher. However, when the laminate is used for passing electronic components through a solder reflow furnace at an ambient temperature of 240 ° C., a heat-fused sheet having a Tg corresponding to the temperature is used. Heating at 240 ° C. or higher is preferred for use. In the present invention, at least two pairs of metal rolls are used, but a laminate roll of a material other than a metal roll such as rubber may be used as necessary. The pressurizing method is not particularly limited as long as a predetermined pressure can be applied. Examples thereof include a hydraulic method, a pneumatic method, and a gap pressure method, and the pressure is not particularly limited.

The structure of the laminating rolls is preferably two or more pairs, and the heating temperature of each one-to-one laminating roll is gradually lowered, and the laminated flexible laminate is gradually cooled. preferable. More specifically, the first-stage laminating roll is pressurized and heated at a temperature equal to or higher than the Tg of the heat-resistant adhesive film and fused with a metal material. Press and heat at a temperature lower than the roll, 3
The second stage slow cooling laminating roll is pressurized and heated at a lower temperature than the second stage slow cooling laminating roll, and the temperature of the last stage slow cooling laminating roll is fixed from the flow state of the heat resistant adhesive film (heat resistant Tg + 30 of adhesive film
° C) or less. If the temperature of the last-stage slow cooling laminating roll is higher than that, the adhesive component of the heat-resistant adhesive film is still in a fluid state, so that fine wrinkles are generated on the resulting flexible laminate. The temperature difference between the main laminating roll and the slow cooling laminating roll may be any number of times, but if the temperature difference is several degrees C, several dozen stages of laminating rolls are required from the main lamination to the Tg of the heat-resistant adhesive film + 30 degrees C , Resulting in high equipment costs. Practically, the temperature difference between the present laminating roll and the slow cooling laminating roll is preferably 50 ° C. or more, and the number of laminating rolls is preferably 2 to 5 in terms of cost.

In the case of the slow cooling lamination, it is important to pass through the slow cooling laminating roll while applying pressure.
By performing slow cooling while applying pressure, generation of wrinkles can be further prevented. The pressure at this time is 15 N / mm
~ 75 N / mm is preferred. The diameter of the laminating roll is not particularly limited, and the diameter of the adjacent laminating roll is not particularly limited.

The protective material does not need to be used, but may be used for the purpose of suppressing wrinkles and the like of the laminated product. When a protective material is used, any material can be used as long as it can protect the laminated product from poor appearance such as wrinkles. However, it must be able to withstand the temperature during processing, for example, 250 ° C.
In the case of processing with a polyimide film, a polyimide film or the like having higher heat resistance is effective. The thickness of the protective material is not particularly limited, but is preferably 50 μm or more for the purpose of suppressing the formation of wrinkles in the laminated plate after lamination. It is more preferable that the thickness of the protective material be 75 μm or more, since wrinkle formation can be almost completely suppressed. In addition, as long as the protective material is lightly adhered to the material to be laminated, it is not necessary to particularly perform a surface treatment or the like. Conversely, if the protective material does not adhere to the material to be laminated, surface treatment such as lightly adhere to the protective material side, or similar surface treatment to the copper foil side,
A surface treatment may be applied to both the protective material and the copper foil. In addition, even if the surface treatment is performed for another purpose, such as a rust prevention treatment performed for the purpose of preventing oxidation of the copper foil surface, if the protective material and the material to be laminated are lightly adhered to each other, the surface is not damaged. Processing may be performed.

The temperature of the laminate at the time of peeling the protective material is as follows:
When a thermoplastic resin is used as the material to be laminated, the temperature is preferably equal to or lower than its Tg. More preferably, the temperature is at least 50 ° C. lower than Tg, and still more preferably 10 ° C. lower than Tg.
The temperature is lower than 0 ° C. Most preferably, the protective material is peeled from the laminate at the point of cooling to room temperature. Hereinafter, the present invention will be described in more detail by way of examples.

[0022]

EXAMPLES The present invention will be described in detail with reference to examples and comparative examples of the present invention, but the present invention is not limited to these examples. Hereinafter, in Examples and Comparative Examples, the physical properties of the adhesive layer and the physical properties of the flexible substrate were measured as follows. The peel strength is JIS C6471 "6.5.
In accordance with the "peeling strength", a sample was prepared, a copper foil portion having a width of 5 mm was peeled off at a peeling angle of 180 degrees under a condition of 50 mm / min, and the load was measured. The appearance state of the flexible laminate was visually determined according to the following criteria. ◎ ·· wrinkles in the per ○ ·· 1m ² no wrinkles on wrinkles per more than 5 × ·· 1m ² per 3 or less △ ·· 1m ² wrinkles per 1 or less ○ △ · 1m ² 5 or more wrinkles (Examples 1 to 11) Heat-resistant adhesive film (25 μm thick PIXEO BP HT-142 manufactured by Kaneka Chemical Industry, Tg 190 ° C.) Metal material (18 μm rolled copper foil BH manufactured by Japan Energy)
Y-22B-T), and in a hot roll laminating apparatus as shown in FIGS.
Laminate under the conditions of 50 N / mm, laminating speed 2.0 m / min,
A flexible laminate was obtained. As a result, a flexible laminate having no wrinkles in appearance and no problem in peel strength was obtained. Details are shown in Table 1.

[0023]

[Table 1] (Examples 12 to 14) On both sides of a heat-resistant adhesive film (25 μm thick PIXEO BP HT-142, Tg 190 ° manufactured by Kaneka Chemical Industry), a metal material (18 μm rolled copper foil BHY-22B-T manufactured by Japan Energy) was applied. With a protective material (Apical 125AH manufactured by Kanegafuchi Chemical Co., Ltd.) on both sides,
The laminating temperature, laminating pressure 50 N / mm and laminating speed 2.0 m / min shown in Table 1 were obtained using a hot roll laminating apparatus as shown in FIGS.
Were laminated under the conditions described above to obtain a flexible laminate. As a result, a flexible laminate having no wrinkles in appearance and no problem in peel strength was obtained. Details are shown in Table 2. (Comparative Examples 1 and 2) Using the same material as in Example 1, FIG.
Using a hot roll laminating apparatus as shown in Table 5, lamination was carried out under the conditions of a lamination temperature, a lamination pressure of 50 N / mm and a lamination speed of 2.0 m / min as shown in Table 1 to obtain a flexible laminate. as a result,
Although there was no problem with the peel strength, wrinkles occurred in the laminating direction. Details are shown in Table 2.

[0024]

[Table 2]

[0025]

According to the present invention, the productivity of a flexible laminate in a hot roll laminating apparatus can be remarkably improved. Accordingly, the present invention provides a material that is particularly suitable as a flexible laminate for electronic and electrical equipment.

[Brief description of the drawings]

FIG. 1 is a hot roll laminating apparatus having two pairs of laminating rolls.

FIG. 2 is a hot roll laminating apparatus having two pairs of laminating rolls.

FIG. 3 is a hot roll laminating apparatus having three pairs of laminating rolls.

FIG. 4 is a hot roll laminating apparatus having three pairs of laminating rolls.

FIG. 5 is a hot roll laminating apparatus having three pairs of laminating rolls.

FIG. 6 is a hot roll laminating apparatus having four pairs of laminating rolls.

FIG. 7 is a hot roll laminating apparatus having four pairs of laminating rolls.

FIG. 8 is a hot roll laminating apparatus having four pairs of laminating rolls.

FIG. 9 is a hot roll laminating apparatus having five pairs of laminating rolls.

FIG. 10 is a hot roll laminating apparatus having five pairs of laminating rolls.

FIG. 11 is a hot roll laminating apparatus having five pairs of laminating rolls.

FIG. 12 is a hot roll laminating apparatus having two pairs of laminating rolls.

FIG. 13 is a hot roll laminating apparatus having two pairs of laminating rolls.

FIG. 14 is a hot roll laminating apparatus having three pairs of laminating rolls.

FIG. 15 is a hot roll laminating apparatus having a pair of laminating rolls.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal material 2 Adhesive film 3 Product take-up device 4a-4e Laminate roll 5 Protective film 6 Protective film take-up device

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yasushi Fushiki 33-1-702 Otomae-demachi, Yamashina-ku, Kyoto F-term (reference) 4F211 AA40 AD03 AD08 AG01 AG03 AH36 AR06 TA03 TC02 TD11 TJ30 TN09 TN44 TN52 TN53 TN56 TN58

Claims (9)

[Claims] 1. A method for producing a heat-resistant flexible laminate by laminating a metal material and a heat-resistant adhesive film using a hot-roll laminating apparatus having at least two pairs of metal rolls. A method for producing a heat-resistant flexible laminate, wherein heating temperatures are different from each other. 2. The method for producing a heat-resistant flexible laminate according to claim 1, wherein the heating temperature of each metal roll of the hot roll laminating apparatus differs by 50 ° C. or more. 3. The heating temperature of the last metal roll of the heat roll laminating apparatus is equal to or lower than (glass transition temperature of heat-resistant adhesive film + 30 ° C.). 2. The method for producing a heat-resistant flexible laminate according to item 1. 4. The heat roll laminating apparatus according to claim 1, wherein two or more pairs of metal rolls have different diameters.
The method for producing a heat-resistant flexible laminate according to any one of claims 1 to 3. 5. When a metal foil and a heat-resistant adhesive film are bonded by using the hot roll laminating apparatus, a protective material is disposed between a pressing surface of the apparatus and a material to be laminated. The method for producing a heat-resistant flexible laminate according to any one of claims 1 to 4. 6. A pressurized heat forming by a first-stage metal roll of the hot roll laminating apparatus is performed at 200 ° C. or more,
In addition, the protective material and the material to be laminated are lightly adhered to each other,
The method for producing a heat-resistant flexible laminate according to any one of claims 1 to 5, wherein the protective material is separated from the laminate after cooling. 7. The heat-resistant adhesive film according to claim 1, wherein an adhesive sheet containing 50% by weight or more of a thermoplastic polyimide in an adhesive component is used as the heat-resistant adhesive film. A method for manufacturing a flexible laminate. 8. The method for producing a laminate according to claim 1, wherein a copper foil having a thickness of 50 μm or less is used as the metal material. 9. The method according to claim 1, wherein a polyimide film is used as the protective material.
The manufacturing method of the laminated board as described in the paragraph.