JP3989145B2 - Laminate production method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a laminated plate manufactured by a pressure heating molding apparatus. In particular, the present invention relates to a method for manufacturing a flexible laminate used for electronic and electrical equipment.
[0002]
[Prior art]
A laminate used for a printed circuit board for electronic and electrical equipment is a laminate in which a metal foil is pasted with a thermosetting adhesive such as a thermosetting resin (hereinafter referred to as a thermosetting laminate), heat There is a laminate (hereinafter, referred to as a heat-sealable laminate) pasted with a heat-sealable adhesive such as a plastic resin.
[0003]
Various methods for producing thermosetting laminates have been studied in the past, and resin impregnated paper, resin impregnated glass cloth, etc. and metal foil are pressed using a multistage press or vacuum press, and then heated at high temperature for several hours. A method of obtaining a rigid laminate by curing, a method of laminating a roll-shaped material between a pair of heating rolls, and then thermosetting at a high temperature for several hours to obtain a flexible laminate, double instead of a heating roll A method of heat laminating using a belt press apparatus has been implemented. At that time, for the purpose of solving the problems described below, there is a case where pressure heating molding is performed with a protective material sandwiched between the pressing surface of the apparatus and the material to be laminated. That is, generation of scratches and dents on the surface of the metal foil (Japanese Patent Laid-Open No. Sho 60-109835), warpage of the laminated plate in a curing furnace after heat lamination (Japanese Patent Laid-Open No. Hei 4-89254), or smoothness with a resin pool In some cases, a protective material is used when problems such as hindering smooth lamination due to poor resin-impregnated paper or resin-impregnated glass cloth occur.
[0004]
[Problems to be solved by the invention]
In the case of producing the above-mentioned thermosetting laminate, the pressure heating molding temperature is almost 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 are unlikely to occur.
[0005]
However, in the case of producing a heat-bonding type laminate, heat-bonding cannot be performed unless pressure heating is performed at a temperature equal to or higher than the glass transition temperature (Tg) of the thermoplastic resin constituting the adhesive layer. On the other hand, since the laminate for electronic and electrical equipment is subjected to high temperature heating in the process of component mounting, the thermoplastic resin constituting the adhesive layer is required to have a Tg of at least 180 ° C. or higher. Furthermore, a heat laminating temperature of 200 ° C. or higher is required for the heat fusion. In such a high temperature laminate, there is a problem that a change in thermal expansion / shrinkage of the material to be laminated becomes large, and appearance defects such as wrinkles are likely to occur in the laminated laminate.
[0006]
To explain the cause of wrinkles in more detail, for example, when laminating copper foil and thermoplastic polyimide with a hot roll laminator, the copper foil and thermoplastic polyimide are attached by passing between the press rolls of the hot roll laminator. Combined. At the time of lamination, each material to be laminated is in a state of being expanded by heat, but generally, the linear expansion coefficient of thermoplastic polyimide is larger than the linear expansion coefficient of copper foil. Polyimide is thermally laminated with copper foil, and conversely, during cooling, the thermoplastic polyimide shrinks more in the surface direction than the copper foil. For this reason, the produced laminated board wrinkles in the surface direction. This is because the material retains heat immediately after the lamination when the pressure is released, and the temperature is higher than the Tg of the thermoplastic polyimide, so that the thermoplastic polyimide is in a fluid state and the generation of wrinkles cannot be suppressed. Also contributed.
[0007]
[Means for Solving the Problems]
In view of the above-mentioned problems, the present invention provides a laminate suitable as a flexible substrate material free from defects in appearance such as wrinkles generated during thermal lamination.
[0008]
That is, when the present inventors laminate a protective material on the outside of the copper foil during lamination in the same system as described above, the thermoplastic polyimide after lamination tends to shrink, but there is a protective material on the outside of the copper foil. For this reason, it was found that the movement in the surface direction is suppressed, the movement of the thermoplastic polyimide is restricted, and wrinkles are not generated.
[0009]
Accordingly, the present invention is a method for manufacturing a laminated board in which a plurality of laminated materials including a heat-fusible laminated material are bonded together by a pressure heating molding device, and the plurality of laminated materials are metal foils. A protective material made of a polyimide film between the pressing surface of the device and the metal foil, and pressurizing and heating at 200 ° C. or higher. After cooling, the protective material is It is a manufacturing method of a laminated board which peels from a laminated board. Here, the material to be laminated means a sheet-like or plate-like material that is finally integrated as a laminated plate, and the material to be laminated is a heat-fusible material to be laminated. A material to be laminated that has the function of bonding. Further, the protective material refers to a non-constituent material of the laminated board. In the case of adopting a method such as pressure heating molding in multiple stages, the protective material can be disposed without contacting or adjacent to the pressure surface of the pressure heating molding apparatus.
[0010]
Furthermore, the present invention uses a copper foil having a thickness of 50 μm or less as the metal foil. Further, a plastic film containing 50% by weight or more of thermoplastic polyimide is used as the plastic film. The pressure heating molding apparatus is a hot roll laminating machine or a double belt press machine. A long sheet-like material wound in a roll shape is used as at least one of a material to be laminated and a protective material.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Details of the present invention will be described below.
[0012]
Although the use of the laminated board obtained by the manufacturing method of this invention is not specifically limited, It is mainly used as a flexible laminated board for electronic electricity.
[0013]
Examples of the heat-sealable laminated material include a thermoplastic resin film, a heat-sealable adhesive sheet, a thermoplastic resin-impregnated paper, and a thermoplastic resin-impregnated glass cloth. A resin film and a heat-fusible adhesive sheet are preferable. As the thermoplastic resin film, those having heat resistance are preferable, and examples thereof include molded articles such as thermoplastic polyimide, thermoplastic polyamideimide, thermoplastic polyetherimide, and thermoplastic polyesterimide. Thermoplastic polyimide and thermoplastic polyester Imides can be used particularly preferably. A heat-fusible adhesive sheet containing 50% or more of these heat-resistant thermoplastic resins is also preferably used in the present invention, and in particular, heat-sealing containing a thermosetting resin such as an epoxy resin or an acrylic resin. It is preferable to use an adhesive sheet. Various additives may be blended in the heat-fusible sheet to improve various properties.
[0014]
In the present invention, the laminated material is not particularly limited, but two or more kinds of laminated materials, more preferably two kinds selected from metal foil, plastic film, resin-impregnated paper, resin-impregnated glass cloth, and resin-impregnated glass nonwoven fabric. It is preferable to bond the above laminated material, particularly a metal foil and a plastic film.
[0015]
As the metal foil, a copper foil is preferable, and a copper foil of 50 μm or less is more preferable. In particular, a copper foil having a thickness of 35 μm or less is less stiff than a copper foil having a thickness larger than that, and is likely to be wrinkled when thermally laminated. Therefore, the present invention exerts a remarkable effect on a copper foil having a thickness of 35 μm or less. In addition, examples of the copper foil include rolled copper foil, electrolytic copper foil, HTE copper foil and the like, and are not particularly limited, and an adhesive may be applied to these surfaces.
[0016]
Examples of the plastic film include a thermosetting resin film, an adhesive sheet in which a thermosetting resin is B-staged, a thermoplastic resin film, a heat-fusible adhesive sheet, and a non-thermoplastic resin film. A typical example of the non-thermoplastic resin film is a polyimide film. If necessary, an adhesive may be applied to one or both sides of the plastic film, or a film that has already been laminated may be further subjected to lamination molding according to the present invention.
[0017]
The pressure heating molding device is not particularly limited as long as the material to be laminated is heated and laminated by applying pressure. For example, a single-acting press device, a multistage press device, a vacuum press device, a multistage vacuum press device, an autoclave. An apparatus, a hot roll laminating machine, a double belt press machine, etc. are mentioned, Among these, a hot roll laminating machine and a double belt press machine can be preferably used. In particular, when a long sheet-like material wound in a roll shape as a material to be laminated and a protective material is used in combination with these apparatuses, it is possible to continuously produce a laminated plate, leading to an improvement in productivity. The heating method is not particularly limited as long as it can be heated at a predetermined temperature, and examples thereof include a heat medium circulation method, a hot air heating method, and a dielectric heating method. The heating temperature is preferably 200 ° C. or higher. However, when the laminate is used for passing through a solder reflow furnace having an atmospheric temperature of 240 ° C. for mounting electronic components, a heat-sealing sheet having a Tg corresponding thereto is used. Heating at 240 ° C. or higher is preferred for use. The pressurization method is not particularly limited as long as a predetermined pressure can be applied, and includes a hydraulic method, a pneumatic method, a gap pressure method, and the like, and the pressure is not particularly limited.
[0018]
Any protective material may be used as long as it satisfies the purpose of protecting against appearance defects such as wrinkles of laminated products. However, it must be able to withstand the temperature during processing. For example, when processing at 250 ° C., a polyimide film having higher heat resistance is effective. The thickness of the protective material is not particularly limited, but a thickness of 75 μm or more is preferable for the purpose of suppressing wrinkle formation of the laminated board after lamination.
[0019]
When the thermoplastic resin is used as the material to be laminated, the temperature of the laminate when peeling the protective material is preferably a temperature equal to or lower than the Tg. More preferably, the temperature is 50 ° C. or more lower than Tg, and more preferably 100 ° C. or more lower than Tg. Most preferably, the protective material is peeled off from the laminate when cooled to room temperature. Hereinafter, the present invention will be described in more detail with reference to examples.
[0020]
【Example】
In the examples, the glass transition temperature (Tg) was measured by Shimadzu DSC CELL SCC-41 (differential scanning calorimeter) in a temperature range from room temperature to 400 ° C. at a heating rate of 10 ° C./min under a nitrogen stream. It was measured.
[0021]
Example 1
An 18 μm electrolytic copper foil is placed on both sides of a 25 μm thermoplastic polyimide film (PIXEO TP-T, manufactured by Kaneka Chemical Co., Ltd.) having a Tg of 190 ° C., and a 125 μm polyimide film (Kanebuchi Chemical Industry Co., Ltd.) as a protective film on both sides. Apical 125AH manufactured by Co., Ltd. was disposed, and a flexible laminate was produced with a hot roll laminator (temperature 260 ° C., L / S 0.5 m / min, linear pressure 100 kgf / cm).
[0022]
As a result, a flexible laminated board free from defects such as wrinkles was obtained.
[0023]
Example 2
An 18 μm rolled copper foil that is more likely to wrinkle than the electrolytic copper foil of Example 1 is disposed on both sides of the 25 μm thermoplastic polyimide film (Tg 190 ° C.), and the 125 μm polyimide film is disposed on both sides of the rolled copper foil as a protective film. Then, a flexible laminate was produced with a hot roll laminator (temperature 260 ° C., L / S 0.5 m / min, linear pressure 100 kgf / cm).
[0024]
As a result, a flexible laminated board free from defects such as wrinkles was obtained.
[0025]
Example 3
An 18 μm electrolytic copper foil is arranged on both sides of the 25 μm thermoplastic polyimide film (Tg 190 ° C.), and the 125 μm polyimide film is arranged on both sides as a protective film, and a double belt press machine (temperature 300 ° C., L / S 0.5 m / min, linear pressure 100 kgf / cm) to produce a flexible laminate.
[0026]
As a result, a flexible laminated board free from defects such as wrinkles was obtained.
[0027]
Example 4
An 18 μm rolled copper foil which is more likely to be wrinkled than the electrolytic copper foil of Example 3 is disposed on both sides of the 25 μm thermoplastic polyimide film (Tg 190 ° C.), and the 125 μm polyimide film is disposed on both sides as a protective film. Then, a flexible laminate was produced with a double belt press (temperature 260 ° C., L / S 0.5 m / min, linear pressure 100 kgf / cm).
[0028]
As a result, a flexible laminated board free from defects such as wrinkles was obtained.
[0029]
Comparative Example 1
A flexible laminate was obtained in the same manner as in Example 1 except that the protective film of 125 μm polyimide film was not used.
[0030]
As a result, wrinkles with vertical streaks in the laminating direction occurred.
[0031]
Comparative Example 2
A flexible laminate was obtained in the same manner as in Example 2 except that the protective film 125 μm polyimide film was not used.
[0032]
As a result, wrinkles with vertical streaks in the laminating direction occurred.
[0033]
Comparative Example 3
A flexible laminate was obtained in the same manner as in Example 3 except that the protective film of 125 μm polyimide film was not used.
[0034]
As a result, wrinkles with vertical streaks in the laminating direction occurred.
[0035]
Comparative Example 4
A flexible laminate was obtained in the same manner as in Example 4 except that the protective film of 125 μm polyimide film was not used.
[0036]
As a result, wrinkles with vertical streaks in the laminating direction occurred.
[0037]
【The invention's effect】
By using the method for manufacturing a laminate according to the present invention, a laminate having a good appearance can be obtained even when a rolled copper foil that tends to wrinkle during lamination is used. Accordingly, the present invention provides a material suitable as a flexible laminate for an electronic / electric device.

Claims (5)

A method for producing a laminated board in which a plurality of laminated materials including a heat-fusible laminated material are bonded together by a pressure heating molding device,
The plurality of materials to be laminated are two or more kinds of materials to be laminated including a metal foil. A protective material made of a polyimide film is disposed between the pressure surface of the device and the metal foil, and pressure heating at 200 ° C. or higher. A method for producing a laminated board, comprising molding and peeling off the protective material from the laminated board after cooling. As the metal foil, thickness using the following copper foil 50 [mu] m, method for manufacturing a laminated board for mounting serial to claim 1. The manufacturing method of the laminated board of any one of Claim 1 or Claim 2 using the plastic film containing 50 weight% or more of thermoplastic polyimides as a to-be-laminated material. The manufacturing method of the laminated board of any one of Claim 1 thru | or 3 whose pressurization heating molding apparatus is a hot roll laminating machine or a double belt press machine. The manufacturing method of the laminated board of any one of Claim 1 thru | or 4 which uses the elongate sheet-like thing wound by roll shape as at least one of a to-be-laminated material and a protective material.