JP2002064259A - Method of manufacturing heat-resistant flexible board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing heat-resistant flexible board suited to flexible board materials, having no appearance defects, such as curing produced during heat lamination. SOLUTION: The method of manufacturing a laminate board, made by bonding a plurality of laminating materials including heat meltable laminating materials, uses a heating and pressing forming apparatus. A protective material is laid between a pressing surface of the apparatus, the laminating material and the heating and pressing forming is applied at 200 deg.C or higher; and the protective material is peeled off a laminate board, after cooling. In a step of peeling off the protective materials the laminate board, the upper and lower protective materials are peeled off at angles symmetric with the symmetric axis of the laminate board.

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. In the case of producing these thermosetting laminates, the heat and pressure molding temperature is almost 200 ° C. or less in most cases. 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. As a method for manufacturing these thermosetting laminates, there is a method in which a protective material is sandwiched between a pressing surface of an apparatus and a material to be laminated, followed by pressurizing and heating. (JP-A-60-
However, in the case of manufacturing a heat-sealing type laminated board, heat-sealing must be performed at a temperature not lower than the glass transition temperature (Tg) of the thermoplastic resin constituting the adhesive layer unless pressure-heating is performed. I can't wear it. On the other hand, laminates for electronic and electrical equipment are subject to high-temperature heating during the component mounting process,
At least 180 ° C for the thermoplastic resin that constitutes the adhesive layer
The above Tg is required. Therefore, a heat lamination temperature of 200 ° C. or more is required for the heat fusion. Lamination at such a high temperature has a problem that the change in thermal expansion and thermal shrinkage of the material to be laminated is large, and the laminated laminate tends to have poor appearance such as wrinkles.

[0004]

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a laminated board suitable as a flexible substrate material free from appearance defects such as wrinkles and curls generated during thermal lamination.

[0005]

Means for Solving the Problems When a specific protective material is disposed between a pressing surface and a material to be laminated and laminated, the thermoplastic polyimide after lamination tends to shrink, but the copper foil Since the protective material is on the outside, movement in the surface direction is suppressed, and movement of the thermoplastic polyimide is restricted, so that wrinkles do not occur. In addition, when peeling the laminated laminate and the upper and lower protective films, the protective material is peeled from the laminate at an angle that is vertically symmetrical with respect to the axis of symmetry of the laminate, thereby greatly reducing the curl of the laminate that occurs at the time of peeling. He found that he could do that. That is, 1) a method for manufacturing a laminated board in which a plurality of materials to be laminated including a heat-fusible material to be laminated are bonded by a heating and pressing molding device, wherein a pressing surface of the device and a material to be laminated are bonded. Place the protective material in between, and perform hot press molding at 200 ° C or higher,
A method of manufacturing a laminate by peeling the protective material from the laminate after cooling, wherein in the step of peeling the protective material and the laminate, the upper and lower protective materials are separated at a symmetric angle with the laminate as a symmetric axis. A method for producing a laminate. 2) The method for producing a laminate according to 1), wherein the laminate material is continuously bonded by heating and pressing. 3) The method for producing a laminate according to 1) or 2), wherein the thickness of the protective material is 50 μm or more. 4) The method for manufacturing a laminate according to any one of 1) to 3), wherein two or more kinds of materials to be laminated are bonded. 5) As the material to be laminated, a metal foil having a thickness of 50 μm or less is used.
13. The method for producing a laminate according to the above item. 6) The method for producing a laminate according to any one of 1) to 5), wherein an adhesive material containing 50% by weight or more of a thermoplastic polyimide is used as the heat-fusible material to be laminated. . 7) The method for producing a laminate according to any one of 1) to 6), wherein the press-heating and forming apparatus is a hot roll laminator or a double belt press. 8) The production of a laminated board according to any one of 2) to 7), 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. Method. 9) The method for producing a laminate according to any one of 1) to 8), wherein the protective material is repeatedly used.

[0006]

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. In the present invention, the material to be laminated refers to a sheet-like or plate-like material that is finally integrated as a laminated plate, and the heat-fusible material to be laminated is a material to be laminated by heating. A material to be laminated having a function of bonding together. The protective material refers to a non-constituent material of the laminate. In the case of employing a method such as performing heating and pressing in multiple stages, the protective material may be disposed without contacting or adjacent to the pressing surface of the heating and pressing device.

Examples of the heat-fusible material to be laminated used in the present invention include a thermoplastic resin film, a heat-fusible adhesive sheet, a thermoplastic resin-impregnated paper, a thermoplastic resin-impregnated glass cloth, and the like. For a flexible laminate, a thermoplastic resin film and a heat-fusible adhesive sheet are preferable. As the thermoplastic resin film, those having heat resistance are preferable, for example, molded products such as thermoplastic polyimide, thermoplastic polyamide imide, thermoplastic polyether imide, and thermoplastic polyester imide, and the like, thermoplastic polyimide, thermoplastic polyester An imide can be used particularly preferably. 50% of these heat-resistant thermoplastic resins
The heat-fusible adhesive sheet containing the above is also preferably used in the present invention, and particularly, the use of a heat-fusible adhesive sheet containing a thermosetting resin such as an epoxy resin or an acrylic resin is also preferable. Further, various additives may be blended in the heat-fusible sheet for improving various properties.

The constitution of the heat-resistant adhesive material is not particularly limited, but may be composed of one adhesive layer as long as it has a certain degree of rigidity and sufficient insulating properties and adhesiveness. In order to obtain the rigidity of the adhesive material, a three-layer structure may be used by using a rigid non-thermoplastic polyimide film at the center of the adhesive layer.

The method for producing the heat-fusible material to be laminated is not particularly limited, but when it is composed of one adhesive layer, it can be formed by a belt casting method, an extrusion method or the like.
The composition of the heat-resistant adhesive material is adhesive layer / core film /
When consisting of three layers such as an adhesive layer, a method of applying an adhesive layer on both sides of the core film, one side at a time, or both sides at the same time, particularly, when using a polyimide-based adhesive, apply with a polyamic acid, There are a method of imidization and a method of applying and drying a soluble polyimide resin as it is. In addition, there is a method of coextruding each resin of the adhesive layer / core film / adhesive layer to form a heat-resistant adhesive material at a time.

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

The metal foil is preferably a copper foil.
A copper foil of μm or less is 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. Also,
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 the surface thereof.

Examples of the plastic film include a thermosetting resin film, an adhesive sheet in which the thermosetting resin is B-staged, and a non-thermoplastic resin film. 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 heating / pressing molding 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,
An induction 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.

In the present invention, a protective material, which is a material for protecting appearance defects such as wrinkles, is essential. Incidentally, Japanese Patent Application Laid-Open Nos. Sho 60-109835 and 4-89254.
Describes a method of hot pressing under a protective material between a pressing surface of an apparatus and a material to be laminated. In each case, a thermosetting type laminated board is manufactured, and therefore, the pressure and heat molding temperature is almost as low as 200 ° C. or less, and appearance defects such as wrinkles are originally unlikely to occur. The purpose is not to prevent the generation of wrinkles, which is the effect of the present invention, but to prevent the occurrence of scratches and dents on the metal foil surface and to prevent the occurrence of warpage of the laminate in a curing furnace after thermal lamination. there were. Alternatively, there is a case where a protective material is used when a problem such as smooth lamination is inhibited by a resin-impregnated paper or a resin-impregnated glass cloth having poor smoothness with a resin pool, but the purpose of the present invention is to differ greatly.

The cause of wrinkles will be described in detail. For example, when laminating a copper foil and a thermoplastic polyimide with a hot roll laminating machine, the copper foil and the thermoplastic polyimide are passed between press rolls of the hot roll laminating machine. Are pasted together. At the time of lamination, each laminated material 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,
The thermoplastic polyimide is heat-laminated with the copper foil in a state of being extended more in the plane direction than the copper foil. Conversely, upon cooling, the thermoplastic polyimide shrinks more largely in the plane direction than the copper foil. For this reason, the resulting laminated plate has wrinkles in the surface direction. This is because the material retains heat immediately after 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 flowing state, and the generation of wrinkles cannot be suppressed. This is also considered to be a factor.

Therefore, the protective material cannot play a role as a protective material unless it has a certain degree of hardness when heated, so that the tensile elasticity at the bonding temperature should be 50 kgf / mm ² or more. It is necessary.
If the elastic modulus is less than 50 kgf / mm ² , cracking may occur depending on the laminating pressure. Further, the linear expansion coefficient of the protective material is preferably 100 ppm / ° C. or less. If the coefficient of linear expansion is greater than 100 ppm / ° C., the dimensions of the protective material are significantly changed as compared with the material to be laminated due to the heating-cooling cycle during lamination, so that the surface of the material to be laminated is wrinkled after lamination. Exert.

The protective material must be able to withstand the temperature during processing. For example, when processed at 250 ° C., a polyimide film, copper foil, aluminum foil, SUS foil or the like having a higher heat resistance is used. A metal foil or the like is effective. When a commercially available polyimide film is used, the thickness of the protective material is preferably 75 μm or more from the viewpoint 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, even 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.

Immediately after lamination, the protective material and the laminate are slightly fused, and when the laminate and the upper and lower protective materials are peeled off, if the peeling path line is asymmetrical in the upper and lower directions, either the upper or lower protective material is used. Since the protective material and the laminate are slightly fused when the remaining protective material and the laminate are peeled off first, the laminate is peeled while being pulled toward the protective material. Curls. In order to prevent this, when peeling the upper and lower protective materials, it is preferable to make the peel angle of the upper and lower protective materials equal with the laminated plate as the axis of symmetry. At this time, the difference between the peeling angles of the upper and lower protective materials is
It is preferably within 30 degrees, more preferably within 10 degrees.

In the present invention, the above-mentioned protective material can be used repeatedly. In addition to installing the feeding and winding device for the material to be laminated before and after the hot roll laminating machine, by installing the feeding and winding device for the protective material in parallel, the protective material once used for lamination can be wound. The protective material can be reused by winding it up with the take-up device and installing it again on the payout side. At the time of winding, an end position detecting device and a winding position correcting device may be installed, and the ends of the protective material may be precisely aligned and wound.

Hereinafter, the present invention will be described in more detail by way of examples.

[0023]

(Examples 1 and 2) Rolled copper foil of 18 μm on both sides of a thermoplastic polyimide film (PIXEO TP-T manufactured by Kaneka Chemical Industry Co., Ltd.) of Tg 190 ° C. and 25 μm, and polyimide on both sides as a protective material A film (Apical 125AH manufactured by Kanegafuchi Chemical Industry Co., Ltd.) was arranged as shown in FIG. 1, and a hot roll laminating machine was used.
A heat-resistant flexible laminate was produced under the conditions of a lamination temperature of 300 ° C., a lamination pressure of 50 kgf / cm, and a lamination speed of 2 m / min. As a result, a flexible laminated board free from defects such as wrinkles and curls in appearance was obtained. The linear expansion coefficient is JIS
According to K7197, manufactured by Rigaku Denki Co., Ltd .: Thermal analyzer TMA81
The measurement was performed at a heating rate of 10 ° C./min using a 40.

[0024]

By using the method for producing a laminate according to the present invention, it is possible to obtain a laminate having good curl and good appearance.

[Brief description of the drawings]

FIG. 1A is a diagram showing a first embodiment. (B) It is a figure showing Example 2.

[Explanation of symbols]

 1 Unwinding of copper foil 2 Unwinding of adhesive film 3 Unwinding of protective film 4 Heating and pressurizing roll 5 Winding of protective film 6 Winding of product

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Claims (9)

[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 heating and pressing molding apparatus, wherein a pressing surface of the apparatus and a material to be laminated are A method of manufacturing a laminated board by disposing a protective material in between, performing heat and pressure molding at 200 ° C. or higher, and peeling the protective material from the laminated board after cooling, wherein the protective material and the laminated board are formed. A method for manufacturing a laminated board, wherein, in the peeling step, the upper and lower protective materials are separated at a symmetric angle with the laminated board as a symmetric axis. 2. The method for manufacturing a laminate according to claim 1, wherein said laminate material is continuously bonded by heating and pressing. 3. The method according to claim 1, wherein the thickness of the protective material is 50 μm or more. 4. The method according to claim 1, wherein two or more kinds of materials to be laminated are bonded. 5. The material to be laminated has a thickness of 50 μm.
The method for producing a laminate according to any one of claims 1 to 4, wherein the following metal foil is used. 6. The laminate according to claim 1, wherein an adhesive material containing 50% by weight or more of a thermoplastic polyimide is used as the heat-fusible material to be laminated. Manufacturing method. 7. The method for producing a laminate according to claim 1, wherein the press-heating and forming apparatus is a hot roll laminator or a double belt press. 8. A long sheet material wound in a roll shape,
8. The method according to claim 2, wherein the material is used as at least one of a material to be laminated and a protective material.
13. The method for producing a laminate according to the above item. 9. The method for manufacturing a laminate according to claim 1, wherein the protective material is used repeatedly.