JP2001129918A - Manufacturing method of laminated sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that a change in the thermal expansion and contraction of a material to be bonded becomes large because a thermoplastic resin and a metal foil are laminated at a high temperature and the appearance of the formed laminated sheet becomes unacceptable. SOLUTION: Protective materials are arranged to both surfaces of a laminating materials before lamination to heat and press the laminating materials and, after the laminated sheet is cooled, the protective materials are peeled to produce the laminated sheet free from wrinkles.

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 A laminated board used for a printed circuit board for electronic and electric equipment is 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 laminate bonded with a heat-fusible adhesive such as a thermoplastic resin (hereinafter, referred to as a heat-fusible laminate).

A variety of methods for producing a thermosetting laminate have been studied in the past, and a resin-impregnated paper, a resin-impregnated glass cloth, and a metal foil are pressed using a multi-stage press or a vacuum press.
Then, a method of obtaining a rigid laminate by heat-curing at high temperature for several hours, or a method of laminating a roll-shaped material between a pair of heating rolls and then heat-curing at high temperature for several hours to obtain a flexible laminate In addition, a method of performing thermal lamination using a double belt press device instead of a heating roll has been implemented. At that time, for the purpose of solving the problems described below, there is a case where a heat-press molding is performed with a protective material interposed between the pressurizing surface of the apparatus and the material to be laminated. In other words, generation of scratches or dents on the surface of the metal foil (Japanese Patent Application Laid-Open No. 60-109835), generation of warpage of the laminate in a curing furnace after thermal lamination (Japanese Patent Application Laid-Open No. 4-89254), or smoothness with resin pool A protective material is sometimes used when a problem such as a hindrance to smooth lamination due to poor resin-impregnated paper or resin-impregnated glass cloth occurs.

[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.

[0005] 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 (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. In such high-temperature lamination, the change in thermal expansion and contraction of the material to be laminated becomes large,
There is a problem that appearance defects such as wrinkles are likely to occur in the laminated body.

[0006] The cause of wrinkles will be described in more detail.
For example, when laminating a copper foil and a thermoplastic polyimide by a hot roll laminating machine, the copper foil and the thermoplastic polyimide are bonded by passing between press rolls 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. The polyimide is thermally laminated with the copper foil. Conversely, upon cooling, the thermoplastic polyimide shrinks more in the plane direction than the copper foil. For this reason, the resulting laminated plate has wrinkles in the surface direction. this is,
Immediately after lamination, when 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 the occurrence of wrinkles cannot be suppressed. It has become.

[0007]

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a laminated board suitable as a flexible substrate material free from appearance defects such as wrinkles generated during thermal lamination.

That is, when the present inventors arrange a protective material on the outside of the copper foil during lamination in the same system as described above, the thermoplastic polyimide after laminating tends to shrink, but the protective polyimide is protected on the outside of the copper foil. It has been found that the presence of the material suppresses the movement in the plane direction, and the movement of the thermoplastic polyimide is restricted, so that wrinkles do not occur.

Accordingly, a first aspect of the present invention is a method of manufacturing a laminated board comprising a plurality of materials to be laminated including a heat-fusible material to be laminated, which are bonded together by a pressure and heat forming apparatus. A protective material is placed between the pressing surface and the material to be laminated.
A method for producing a laminate, comprising: performing pressurized heat molding at 0 ° C. or higher, and peeling the protective material from the laminate after cooling. As used herein, the material to be laminated refers to a sheet-like or plate-like material that is finally integrated as a laminate, and the heat-fusible material to be laminated is a material to be laminated which is fused by heating. A material to be laminated having a function of bonding.
The protective material refers to a non-constituent material of the laminate. When using a method such as multi-stage pressurized heat molding,
The protective material may be disposed without contacting or adjacent to the pressing surface of the press and heat forming apparatus.

[0010] Further, a second aspect of the present invention is the method for producing a laminated board according to the first aspect, wherein two or more kinds of materials to be laminated are bonded together. Claim 3 of the present invention
Is a method for manufacturing a laminated board according to any one of claims 1 to 2, wherein a copper foil having a thickness of 50 µm or less is used as a material to be laminated. A fourth aspect of the present invention is the method for producing a laminate according to any one of the first to third aspects, wherein a plastic film containing 50% by weight or more of a thermoplastic polyimide is used as a material to be laminated. . According to a fifth aspect of the present invention, in any one of the first to fourth aspects, a polyimide film is used as the protective material.
It is a manufacturing method of the laminated board as described in the paragraph. According to a sixth aspect of the present invention, the pressure and heat forming apparatus is a hot roll laminating machine or a double belt press.
The method for producing a laminate according to any one of the above. The laminated plate according to any one of claims 1 to 6, wherein a long sheet-like material wound in a roll shape is used as at least one of a laminated material and a protective material. Is a continuous production method.

[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.

Examples of the heat-fusible material to be laminated include a thermoplastic resin film, a heat-fusible adhesive sheet, a thermoplastic resin-impregnated paper, and a thermoplastic resin-impregnated glass cloth. Is preferably a thermoplastic resin film or a heat-fusible adhesive sheet. As the thermoplastic resin film, those having heat resistance are preferable, for example, thermoplastic polyimide, thermoplastic polyamideimide,
Molded products such as thermoplastic polyetherimide and thermoplastic polyesterimide are exemplified, and thermoplastic polyimide and thermoplastic polyesterimide can be particularly preferably used. A heat-sealing adhesive sheet containing 50% or more of these heat-resistant thermoplastic resins is also preferably used in the present invention, and particularly, a heat-sealing sheet containing a thermosetting resin such as an epoxy resin or an acrylic resin. It is preferred to use an adhesive sheet having a property. Further, various additives may be blended in the heat-fusible sheet for improving various properties.

In the present invention, the material to be laminated is not particularly limited, but is preferably selected from two or more materials to be laminated, more preferably, a metal foil, a plastic film, a resin-impregnated paper, a resin-impregnated glass cloth, and a resin-impregnated glass nonwoven fabric. It is preferable to bond two or more kinds of materials to be laminated, in particular, a metal foil and a plastic film.

As the metal foil, a copper foil is preferable.
The following copper foils are more preferred. 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.

Examples of the plastic film include a thermosetting resin film, an adhesive sheet having a B-stage thermosetting resin, a thermoplastic resin film, a heat-fusible adhesive sheet,
Non-thermoplastic resin films and the like can be mentioned. A typical example of the non-thermoplastic resin film is a polyimide film. An adhesive may be applied to one or both surfaces of the plastic film, if necessary, or a film that has already been laminated and formed may be further subjected to the lamination according to the present invention.

The press-heating / forming 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. For example, a single-acting press, a multi-stage press, a vacuum press, a multi-stage vacuum press Equipment, an autoclave device, a hot roll laminating machine, a double belt press machine and the like. Among these, the hot roll laminating machine,
A double belt press can be preferably used. In particular, when a long sheet-like material wound in a roll shape is used in combination with these devices as a material to be laminated and a protective material, continuous production of a laminated plate becomes possible, leading to an improvement in productivity. 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,
Dielectric heating method and the like can be mentioned. 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. 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.

Any protective material can be used as long as it satisfies the purpose of protecting the laminated product from poor appearance such as wrinkles. However, it must be able to withstand the temperature during processing. For example, when processing is performed at 250 ° C., 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 75 μm or more for the purpose of suppressing the formation of wrinkles in the laminated plate after lamination.

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.
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.

[0020]

EXAMPLES The glass transition temperature (Tg) in the examples was measured by a DSC CELL SCC-41 (differential scanning calorimeter) at a heating rate of 10 ° C./min under a nitrogen stream by Shimadzu Corporation.
The measurement was performed in a temperature range from room temperature to 400 ° C.

Example 1 An 18 μm electrolytic copper foil was placed on both sides of a 25 μm thermoplastic polyimide film (PIXEO TP-T manufactured by Kaneka Chemical Industry Co., Ltd.) having a Tg of 190 ° C., and 125 μm polyimide was used as a protective film on both sides. A film (Apical 125AH manufactured by Kanegabuchi Chemical Industry Co., Ltd.) was provided, and a hot roll laminating machine (temperature: 260 ° C., L / S0.
A flexible laminate was produced at a pressure of 5 m / min and a linear pressure of 100 kgf / cm).

As a result, a flexible laminate having no external defects such as wrinkles was obtained.

Example 2 The above-mentioned 25 μm thermoplastic polyimide film (Tg19
(0 ° C.), rolled 18 μm rolled copper foil, which is more likely to generate wrinkles than the electrolytic copper foil of Example 1, and further disposed the 125 μm polyimide film as a protective film on both sides thereof. Temperature 260 ° C, L / S
A flexible laminate was produced at 0.5 m / min at a linear pressure of 100 kgf / cm).

As a result, a flexible laminated board free from defects such as wrinkles in appearance was obtained.

Example 3 The above-mentioned 25 μm thermoplastic polyimide film (Tg19
0 ° C.), an 18 μm electrolytic copper foil is disposed on both sides thereof, and the 125 μm polyimide film is disposed on both sides thereof as a protective film.
C, L / S 0.5 m / min, linear pressure 100 kgf / cm) to produce a flexible laminate.

As a result, a flexible laminated board free from defects such as wrinkles in appearance was obtained.

Example 4 The above-mentioned 25 μm thermoplastic polyimide film (Tg19
(0 ° C.), rolled 18 μm rolled copper foil, which is more likely to wrinkle than the electrolytic copper foil of Example 3, and further disposed the 125 μm polyimide film as a protective film on both sides thereof. 260 ° C, L / S
A flexible laminate was produced at 0.5 m / min at a linear pressure of 100 kgf / cm).

As a result, a flexible laminated board free from defects such as wrinkles in appearance was obtained.

Comparative Example 1 A flexible laminate was obtained in the same manner as in Example 1 except that a 125 μm polyimide film serving as a protective film was not used.

As a result, wrinkles appeared as if vertical streaks were formed in the laminating direction.

Comparative Example 2 A flexible laminate was obtained in the same manner as in Example 2 except that a 125 μm polyimide film serving as a protective film was not used.

As a result, wrinkles were generated as if vertical stripes were formed in the laminating direction.

Comparative Example 3 A flexible laminated board was obtained in the same manner as in Example 3 except that a 125 μm polyimide film as a protective film was not used.

As a result, wrinkles appeared as if vertical streaks were formed in the laminating direction.

Comparative Example 4 A flexible laminated board was obtained in the same manner as in Example 4 except that a 125 μm polyimide film as a protective film was not used.

As a result, wrinkles appeared as if vertical streaks were formed in the laminating direction.

[0037]

By using the method for producing a laminate according to the present invention, a laminate having a good appearance can be obtained even when a rolled copper foil which tends to wrinkle during lamination is used. Accordingly, the present invention provides a material that is particularly suitable as a flexible laminate for electronic and electrical equipment.

Continued on the front page F term (reference) 4F100 AB17A AB33A AK01B AK49B BA02 EA021 EH012 EJ182 EJ422 EJ882 EJ912 EK06 EK08 GB43 JB16B JL04 5E314 AA36 CC15 DD05 EE03 FF06 FF19 GG24

Claims (7)

[Claims] 1. A method for manufacturing a laminated board, comprising laminating a plurality of materials to be laminated including a heat-fusible material to be laminated by a pressure and heat forming apparatus, wherein a pressing surface of the apparatus and a material to be laminated are A method for producing a laminated board, comprising: placing a protective material between them, performing press-heating at 200 ° C. or higher, and peeling the protective material from the laminated board after cooling. 2. The method according to claim 1, wherein two or more kinds of materials to be laminated are bonded. 3. 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 material to be laminated. 4. The method according to claim 1, wherein a plastic film containing 50% by weight or more of a thermoplastic polyimide is used as the material to be laminated. 5. The method for producing a laminate according to claim 1, wherein a polyimide film is used as the protective material. 6. The method for producing a laminated board according to claim 1, wherein the pressurizing and heating forming apparatus is a hot roll laminating machine or a double belt press. 7. A long sheet material wound in a roll shape,
The continuous manufacturing method of a laminated board according to any one of claims 1 to 6, wherein the method is used as at least one of a material to be laminated and a protective material.