JPH0519838B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a novel method for manufacturing a flexible double-sided copper-clad board used for printed circuit boards. [Prior Art] This type of copper-clad board has conventionally been generally manufactured by coating copper foil with epoxy prepreg or polyimide prepreg containing a glass cloth base material, and then hot pressing. However, the above method has drawbacks such as easy entrainment of air bubbles, poor reliability of withstand voltage, and difficulty in continuous production. [Summary of the Invention] The present invention has been made to solve the above-mentioned drawbacks, and consists of two pieces of long copper foil with an insulating layer formed on one side by electrodeposition coating, and the surfaces of the insulating layer overlapped. This paper proposes an economical, highly reliable, and continuous production method for producing flexible double-sided copper-clad plates by bonding or fusing them. [Structure of the Invention] In the present invention, a water-dispersed electrodeposition paint that can be cured by heating or a mixture of a water-dispersion type electrodeposition paint that cannot be cured by heating is used as an electrodeposition paint, and is applied to one side of a copper foil by electrodeposition coating. After forming a deposited layer and immersing the deposited layer in an organic solvent, the moisture and organic solvent in the deposited layer are brought out by heating to form a continuous insulating layer. Then, the obtained two single-sided copper-clad boards are stacked with their insulating layers on top of each other and bonded together using a hot press to form a double-sided copper-clad board. With this method, the interface between the copper foil and the insulating layer has a much higher adhesion strength than normal pre-freg bonding, so excellent adhesion strength can be obtained not only with electro-field copper foil but also with rolled copper foil. It will be done. When forming a continuous film, it is necessary to bring the film to a so-called B stage state rather than completely curing it, so the heating conditions will depend on the reliability of the electrodeposition paint. 10~ at 100~200℃
30 minutes is suitable. When two single-sided copper-clad boards thus obtained are bonded together by hot pressing, suitable conditions are 200 to 300°C for 10 to 30 minutes and a pressure of 2 kg/cm ² or more. If the temperature is less than 150°C, less than 10 minutes, or less than 2 kg/cm ² , the adhesive strength between the insulating film and the copper foil will be poor, and this is not practical. When adhering with a hot roll, the roll pressure is 5
Kg/cm ² or higher is desirable, and even after passing through the rolls, it is desirable to post-cure in a heating furnace set at 200°C or higher. Furthermore, when bonding two single-sided copper-clad boards together, a fibrous base material may be added to the bonding surface to create a reinforcing effect.Also, when adhesive is applied to one-sided copper-clad boards, the insulating film, especially in stage B, There is no need to set the conditions, and there is an advantage that the curing conditions can be freely selected. As the fibrous base material used here, glass or polyamide can be used, and suitable examples include glass cloth (Arisawa Seisakusho, EPC050, EPC102,
EPC160, LPC070, LPC110) and aromatic polyamide (Kanebo Glass Fiber Co., Ltd., Kevlar 49 Cross K-
120, K-220, K-181, K281), etc. The base material is usually used in the form of a cloth, but it may also be a non-woven fabric. Although there is no limit to the thickness, if no adhesive is used, the thickness of the electrodeposited insulating film must be sufficiently larger than the thickness of the cloth. There are no particular restrictions on the adhesive; acrylic, epoxy,
Phenol type, rubber type, etc. can be used. As the thermosetting water-dispersed electrodeposition paint used in the present invention, acrylic-modified epoxy-based electrodeposition paint, polyesterimide-based electrodeposition paint, etc. can be used.
When used for printed circuit boards, paints with excellent heat resistance (high temperature, short-term solder resistance) are desirable. As the thermoplastic water-dispersed electrodeposition paint used in the present invention, phenoxy resin, polyphenylene sulfide, polyether sulfone, etc. are used.
As an example of electrodeposition paint, the above resin is coated with a thickness of 30 μm.
The following method is adopted in which the pulverized material is dispersed in water containing a surfactant. As the surfactant used here, if the above-mentioned thermosetting water dispersion paint is anionic, an anionic surfactant is used, and preferred examples include sodium lauryl benzene sulfonate and sodium lauryl sulfate ester. can be given. The concentration of the electrodeposition paint is preferably about 5 to 20%, and
% or less, it takes time to obtain the desired film thickness, and if it is 20% or more, a process such as washing the electrodeposited layer with water before heating is required, which is not preferable. Of course, when using the above-mentioned electrodeposition paint, in order to obtain a smoother insulating film, it is also possible to add a small amount (0.01 to 0.1%) of a fluorocarbon surfactant that provides a leveling effect to the paint. When the electrodeposited layer obtained in this way is immersed in an organic solvent for a short time, the water-dispersed particles of the deposited layer are partially swollen by the organic solvent, and a continuous film without pinholes can be formed by heating. . [Embodiment of the invention] The figure is a system diagram showing an embodiment of the invention.
In the figure, 1 is a copper foil, 2 is a fibrous base material, 3 is an electrodeposition tank, 4 is a counter electrode, 5 is an electrodeposition paint, 6 is an organic solvent vapor tank, 7 is a primary baking furnace, 8 is a hot roller,
9 is a secondary baking furnace, and 10 is a winding machine. The method for producing a flexible double-sided copper-clad board is to introduce a continuous copper foil 1 into an electrodeposition tank 3 filled with an electrodeposition paint 5, and to use the copper foil side as an anode and a counter electrode 4 provided in the electrodeposition tank 3. A voltage is applied during this period, and a deposited layer is formed by electrodeposition coating. Next, the copper foil 1 is passed through an organic solvent vapor bath 6 for organic solvent vapor treatment, and then the temperature is
It is heated through a primary baking furnace 7 at 100 to 300°C, and then the fibrous base material 2 is sandwiched or not sandwiched, and the electrodeposited surfaces are overlapped and heated to a temperature of 200 to 300°C.
Heat-seal with hot roller 8 at 400℃. When an adhesive is used, it may be applied before entering the hot roller 8, or when a fibrous base material 2 is used, the adhesive may be applied to the base material in advance. The obtained laminate is further hardened in a secondary baking furnace 9 if necessary, and the obtained flexible double-sided copper-clad substrate is wound up in a winding machine 10. When using a press instead of the hot roller 8, the single-sided copper-clad plate that comes out of the primary baking furnace 7 may be cut to a certain length, the coated sides of the two sheets overlapped, and then pressed, or the hot roll can be used to You may also use a method of repeating the press while extruding pieces of the same size. Reference examples and examples will be described below. Reference Example 1 Put 1,900 g of ion-exchanged water and 2.4 g of lauryl sulfate ester soda into a four-necked flask, and pass N ₂ gas through it for about 30 minutes while stirring. then N ₂
Stop passing gas and raise the temperature to 70℃.
Next, after adding a solution of 2.0 g of ammonium persulfate and 0.7 g of sodium bisulfite dissolved in 100 g of ion exchange water, immediately 240 g of acrylonitrile,
A mixed solution of 60 g of α-methylstyrene, 60 g of styrene, 20 g of methacrylic acid, and 20 g of glycidyl methacrylate was added dropwise over about 30 minutes, and after the addition was completed, the mixture was reacted at 70°C for 3 hours to form a thermosetting water dispersion with a non-volatile content of 19.5%. Electrodeposition paint (A) was produced. Reference example 2 Diaminodiphenylmethane in a four-necked flask
206g, anhydrous trimelitz 400g, m-cresol
After preparing 600g and reacting at 150℃ for 1 hour,
Raise the temperature to 200℃, polyethylene terephthalate 400
g, 200 g of tris (β-hydroxy ester) isocyanurate, and 4 g of tetrabutyl titanate were added and dissolved. Then, after reacting at 220 to 240°C for about 3.5 hours while distilling m-cresol and the produced ethylene glycol out of the system,
1.2 g of FC431 (fluorine surfactant, manufactured by 3M) was added and stirred for about 15 minutes to obtain a polyesterimide resin. The obtained resin was pulverized with a jet mill to an average particle size of 11 μm. Add 500g of this powder to ion-exchanged water containing 5g of laluryl sulfate ester soda.
A thermosetting water-dispersed electrodeposition paint (B) with a non-volatile content of about 10% was produced by dispersing it in 4500 g of water. Reference Example 3 Phenoxy resin (manufactured by UCC, PHKK) was ground to an average particle size of 14 μm using a jet mill, and this powder was
500g of sodium laurylbenzenesulfonate 5g
A thermoplastic dispersion electrodeposition paint (C) with a non-volatile content of about 10% was produced by dispersing it in 4,500 g of ion-exchanged water containing the following. Reference example 4 Polyether sulfone (Mitsui Toatsusha,
Victrex) was ground to an average particle size of 13 μm using a diet mill, and 500 g of this powder was dispersed in 4500 g of ion-exchanged water containing 4.0 g of sodium laurylbenzenesulfonate and 1.0 g of FC431 (3M, fluorine-based surfactant). A thermoplastic water-dispersed electrodeposition paint (D) with a non-volatile content of about 10% was produced. Examples 1 to 6 Flexible double-sided copper-clad boards were manufactured according to the manufacturing method shown in the figure using the electrodeposition paint, fiber base material, adhesive, and organic solvent shown in Table 1 under the conditions shown in Table 1. Copper foil 1 is the width
It is a continuous foil of 500mm and 25μm thick, and the applied voltage for electrodeposition is 50V. The properties of the obtained flexible double-sided copper clad board are also listed in Table 1.

【table】

〔Effect of the invention〕

According to the present invention, two sheets of long copper foil with an insulating layer formed on one side by electrodeposition coating are bonded together, so there is no air bubbles involved, and the reliability of withstand voltage is high. This has the effect of providing a flexible double-sided copper-clad board with excellent solder heat resistance and peel strength.

[Brief explanation of the drawing]

The figure is a system diagram showing a method for manufacturing a flexible double-sided copper clad plate according to an embodiment of the present invention. In the figure, 1 is a copper foil, 2 is a fibrous base material, 3 is an electrodeposition tank, 4 is a counter electrode, 5 is an electrodeposition paint, 6 is an organic solvent vapor tank, 7 is a primary baking furnace, 8 is a hot roller, 9 1 is a secondary baking furnace, and 10 is a winding machine.

Claims (1)

[Claims] 1. A method comprising two single-sided copper-clad boards each having an insulating layer formed on one side by electrodeposition coating on a long copper foil, which are bonded or fused together with the insulating layer surfaces overlapped. A method for manufacturing flexible double-sided copper clad plates. 2. The flexible double-sided copper cladding according to claim 1, characterized in that when the insulating layer surfaces of two single-sided copper clad boards are superimposed and bonded or fused, a fibrous base material is sandwiched. Method of manufacturing the board. 3. The flexible double-sided copper according to claim 1 or 2, characterized in that an adhesive is applied when the insulating layer surfaces of two single-sided copper-clad boards are overlapped and bonded or fused. Method of manufacturing veneer. 4. Claim 1, characterized in that when the insulating layer surfaces of two single-sided copper-clad boards are overlapped and bonded or fused, a fibrous base material coated or impregnated with an adhesive is sandwiched. A method for manufacturing a flexible double-sided copper clad board as described in .