JPS61276290A - Circuit transfer body and transfer method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a circuit transfer body and a transfer method, and more specifically, a circuit printed on a support film by a printing means such as screen printing is transferred to a transferred body, such as a wiring board, etc. The present invention relates to a circuit transfer body and a transfer method that can be easily manufactured.

[Technical background of the invention]

Conventionally, methods for forming electrical circuits such as wiring boards include: (1) forming a thin copper film on a wiring board substrate, laminating a mask in the shape of a circuit pattern, and chemically etching the thin film to form a circuit; A method that uses a special plating method that applies plating only to the circuit part; 2) In addition, a conductive thin film is formed over the entire surface of the support film, and while it is laminated on the transfer target, only the circuit part (transfer part) is heated. There are known methods such as a method of forming a circuit by transferring only the circuit portion onto an object to be transferred using a hot platen that can be pressed (Japanese Patent Application Laid-open No. 141789/1989).

In the circuit formation method described above, the method of etching the copper thin film is a method that has been used for a long time and is still widely used today, but the copper thin film other than the circuit part must be removed by melting. This has disadvantages in that materials are wasted and expensive, and when a thin copper film is chemically etched using nitric acid, the copper edges of the masked circuit parts are slightly dissolved. There are also drawbacks.

Further, although the method of plating only the circuit portion does not result in the above-mentioned waste of materials, it has the disadvantage that it requires special plating equipment and a large amount of capital investment.

Furthermore, a method for forming a circuit in which a conductive thin film is laminated on the entire surface of the support film and then transferred using a hot platen that can heat and press only a predetermined portion requires a hot platen that can heat and press only a predetermined portion. Furthermore, since the conductive thin film other than the transfer portion is discarded, there is a disadvantage that material is wasted and costs are inevitably high. Furthermore, in such a transfer method, since the circuit pattern is transferred by heating and pressing only a predetermined portion using the hot platen, it is necessary that the conductive thin film has good sharpness. This cracking of the conductive thin film tends to worsen as the thickness of the thin film increases, so it is not possible to make the conductive thin film thicker.
If the amount of conductive particles is increased, the adhesion of the conductive thin film tends to deteriorate, so it is difficult to manufacture circuits with good conductivity and adhesive strength. There was also.

Furthermore, particularly in the above-described method of forming a circuit by transfer, there is a drawback that it is difficult to transfer to a transfer target such as a rough surface or a thermosetting resin.

[Summary of the invention]

The present invention has been made in view of the above points, and it is possible to form a circuit well without requiring special equipment or expensive equipment, and without increasing costs due to waste of materials. In addition, circuit transfer bodies and circuit transfers that can form circuits with good conductivity and adhesive strength, and can also be transferred to various non-transfer materials, such as thermosetting resins or wood.

The purpose is to provide a method.

Therefore, in the circuit transfer body according to the present invention, 1 part by weight of nonmetallic conductive particles is added to 100 parts by weight of the resin on the support film.
00 to 500 parts by weight of the basic conductive paint is used to print a circuit pattern with a surface resistance of 50 Ω/□ or less, which shows easy peelability when heated and pressurized with the support film, and then prints a circuit pattern on this circuit pattern. Some are characterized by laminating prepreg layers in a semi-cured state by impregnating a base material with a synthetic resin.

Further, in the circuit transfer method according to the present invention, 100 parts by weight of non-metallic conductive particles are added to 100 parts by weight of the resin on the support film.
A circuit pattern with a surface resistance of 50Ω/□ or less, which shows easy peelability when heated and pressurized with the support film, is printed using a conductive paint that is basically made by adding ~500 parts by weight, and then a circuit pattern is printed on this circuit pattern. , A circuit transfer body in which a semi-cured prepreg layer is laminated by impregnating a base material with a synthetic resin is laminated so that the prepreg layer is in close contact with the transferred body, at a temperature of 80 to 250°C, and a pressure of 5 to 10 kg/cm. The method is characterized in that the circuit pattern is transferred at the same time as heating and pressing at 1 ffl to bond the transfer target and the prepreg layer together.

In the circuit transfer body and circuit transfer method according to the present invention, the circuit pattern is printed on the transfer body with conductive paint using a printing method such as screen printing or gravure printing, and the circuit pattern is transferred to the transfer target under heat and pressure. This has the advantage that it is possible to avoid waste of materials, and it is also possible to form a circuit on the transfer target without requiring expensive equipment. In addition, since the circuit pattern printed by screen printing is transferred onto the transfer target, there is no problem of breakage as with the conventional transfer method that uses a hot plate, etc., and therefore the thickness of the circuit pattern can be increased. This has the advantage that it is possible to form a circuit with good conductivity, excellent adhesive strength, and precision.

Furthermore, in the circuit transfer body and circuit transfer method according to the present invention, a prepreg layer in which a base material is impregnated with a synthetic resin in a semi-hardened state is further laminated on the circuit pattern, and the prepreg layer is used to transfer the material to the transfer target. Since the circuit pattern is transferred while being bonded, there is an advantage that circuits can be formed even on objects to which transfer is normally impossible or difficult.

[Detailed description of the invention]

As shown in FIG. 1, the circuit transfer body according to the present invention has a circuit pattern 2 formed by printing on a support film 1 a conductive paint that is easily peelable when heated and pressurized in a desired circuit shape. A prepreg layer 3 is further laminated on the circuit pattern 2, the base material being impregnated with a synthetic resin and brought into a semi-cured state. The circuit pattern 2 is required to have the conductivity required for a circuit having a conductive path filled with non-metallic conductive particles, that is, conductivity with a surface resistance of 50Ω/□ or less.

Support film 1 on which such a circuit pattern 2 is formed
is not fundamentally limited in the present invention,
It has good adhesion to the circuit pattern 2 at room temperature, easily peels off from the circuit pattern 2 under heat and pressure, and has heat resistance or smoothness.
Furthermore, a synthetic resin film or the like that is not attacked by the solvent contained in the conductive paint can be effectively used. Specific examples of the support film 1 include polyester film, polyimide film, polypropylene, and silicone-treated release paper.

The conductive paint for printing the desired circuit pattern 2 on the support film 1 described above must be capable of printing a good and fine circuit pattern on the support film 1, and have conductivity that can function as a circuit (50Ω/□ or less). ), and furthermore, it has the basic performance as a transfer body, such as peeling well from the support film 1 when heated and pressurized, and adhering with sufficient strength to the cured prepreg rfI3 without destroying the circuit pattern 2. It is necessary to satisfy various conditions such as:

In order to satisfy these conditions, it is necessary to select the support film, the resin (solvent and solute) that is the base material of the conductive paint, and the type of nonmetallic conductive particles added to this resin. is important, and it is also necessary to consider the amount and particle size of the nonmetallic conductive particles. The resin serving as the base material for such a conductive paint includes a resin component (solute) that has adhesive properties with the support film 1 at room temperature and can form an easily peelable circuit pattern when heated and pressurized, such as an acrylic resin, Vinyl chloride, urethane, polyester resins, etc. or one or more of cyclized rubber, chlorinated rubber, rosin, etc., for example, MEK, MIBK, ketone solvents such as cyclohexanone, aromatic solvents such as toluene, xylene, IPA, butanol, etc. It can be a resin solution dissolved in one or more of alcohol solvents, ether solvents, ester solvents, and the like.

The nonmetallic conductive particles added to the resin solution are not fundamentally limited in the present invention as long as they can be uniformly dispersed in the resin and impart good conductivity. For example, one or more types of carbon particles such as carbon and graphite can be used.

Such nonmetallic conductive particles are added in an amount of 100 to 500 parts by weight per 100 parts by weight of the resin. If it is less than 100 parts by weight, it will be difficult to achieve a surface resistance of 50 Ω/□ or less, which is required for such a circuit filled with non-metallic conductive particles, while if it exceeds 500 parts by weight, it will be difficult to maintain sufficient adhesive properties. There is a risk that you will not be able to do so.

Other additives such as antioxidants, dispersants, etc. can be optionally added to the conductive paint.

Although the circuit pattern 2 is printed on the support film 1 using such a conductive paint, this printing method is not limited in the present invention. For example, it can be effectively printed using known printing methods such as screen printing and gravure printing.

This conductive paint is preferably applied to the support film 1 by:
It is preferable to print to a thickness of 10 to 50 μm.

If the thickness of the conductive paint is less than 10 μm, in order to obtain the above-mentioned conductivity of 50Ω/□ or less, it is necessary to fill it with a large amount of non-metallic conductive particles, which may deteriorate the adhesive strength of the circuit. On the other hand, if it exceeds 50 μm, it may become difficult to print a circuit pattern by screen printing or the like.

In the circuit transfer body according to the present invention, the thickness of the lines of the circuit pattern can be freely changed as described above, and the degree of conductivity can be controlled by the thickness of the lines.

That is, it is possible to change the conductivity without being limited only to the filling amount of the nonmetallic conductive particles, and the degree of freedom in designing the circuit transfer body is improved. In particular, by increasing the thickness of the wire, it is possible to reduce the amount of non-metallic conductive particles filled, which improves the adhesive strength of the transferred circuit and improves the adhesive strength compared to conventional transfer methods. This also improves accuracy.

Naturally, it is preferable that the line width or the distance between lines of the circuit pattern 2 be small. In the circuit transfer body according to the present invention, in order to make it possible to form a circuit with the above-mentioned line width or line-to-line distance of 1 ml or less, the thickness of the lines is increased (to obtain good conductivity), and good adhesive strength is obtained. In order to form a circuit, the viscosity of the conductive paint to be printed is set to 10 to 2.
It is preferable to adjust to 00 voices. If the viscosity of the conductive paint is less than 10 poise, there is a risk that the wires will be distorted and the circuit will be shorted, while if it exceeds 200 poise, it will be difficult to print the circuit pattern on the support film 1. be.

After the circuit pattern 2 is printed on the support film 1 with the conductive paint in this way, a prepreg layer 3 whose base material is impregnated with a synthetic resin and brought into a semi-cured state is laminated on the circuit pattern 2.

The prepreg layer 3 may be of any material as long as it can be well adhered to the circuit pattern 2 and the object to be transferred. For example, it can be semi-cured by impregnating a base material such as glass fiber, paper, or synthetic fiber with synthetic resin such as epoxy, urethane, diallyl phthalate, polyimide, polyester, or phenol.

As mentioned above, the amount of synthetic resin impregnated into the base material is preferably 20 to 70% by volume based on the volume of the base material. If the amount of impregnation is less than 20% by volume, there is a risk that it will not adhere well to the object to be transferred, while if it exceeds 70% by volume, there will be no problem with layer tube adhesion, but it will be difficult to manufacture prepreg with more than 70% by volume. It is from.

In this way, the base material is impregnated with synthetic resin to make it into a semi-hardened state, but the degree of semi-hardening of the prepreg layer 3 basically differs depending on the type of synthetic resin. For example, acrylic resin In this case, if a non-stick material is used, there is no need for a semi-cured state. In the case of epoxy resin, it is preferable that the resin be semi-cured by about 20 to 40%.

The present invention also provides a transfer method using such a circuit transfer body.

According to the circuit transfer method according to the present invention, as shown in FIG.
The prepreg layer 3 is adhered to the transfer target 4 by heat and pressure using a press or the like, and the circuit pattern 2 is transferred.

Such a transfer target 4 may be any material as long as it can be bonded when the prepreg layer 3 is in a hardened state. For example, it may be a thermoplastic resin such as ABS, ^S, HIPS, polyacetal, vinyl chloride, nylon, polycarbonate, polyethylene, a thermosetting resin such as polyimide, epoxy resin, phenol resin, polyester resin, or a wooden board. According to the circuit transfer body according to the present invention, unlike conventional transfer methods,
It is also possible to transfer onto thermosetting resins or wooden boards with rough surfaces, which was previously difficult.

The heating and pressurizing method is not limited in the present invention, and various means can be used. for example,
It is possible to transfer by applying heat and pressure using a heat press or the like.

When the circuit pattern 2 is transferred, it is transferred at a temperature of 80 to 250°C and a pressure of 5 to 10 kg/-. If the transfer temperature is lower than 80°C, there is a risk that the circuit pattern 2 formed on the circuit transfer body will not be transferred, and if it is higher than 250°C, there is a risk that warpage, thermal contraction, thermal deterioration, etc. will occur in the transferred body 4. There is.

Furthermore, if the transfer pressure is less than 5 Kg/-, there is a risk that the circuit pattern will not be transferred well;
This is because if it is larger than A, there is a risk that the circuit pattern 2 will collapse.

After the circuit pattern 2 is transferred to the transfer target 4 via the prepreg layer 3 as described above, the support film 1 is peeled off and a circuit is formed on the transfer target 4.

Example A conductive paint having the following composition (viscosity: 70 voids) was used on a silicone-treated release film, with a line width of 0.5 II 1 m,
A circuit pattern was printed with a line distance of 0.5 mrrl and a thickness of 15 μm.

Composition Acrylic resin 100 parts by weight Ester and ketone solvents 180 parts by weight Graphite 320 parts by weight Conductive carbon ioo parts by weight Paper was impregnated with epoxy resin on the printed circuit pattern as described above, and the semi-cured state (20 parts by weight) The prepregs (hardened by about 40%) were laminated to form a circuit transfer body.

The prepreg layer of the circuit transfer body manufactured in this way was brought into close contact with the epoxy resin transfer body, and
When the circuit pattern was transferred with a pressure of 8Kg/cJ at a temperature of ℃, there were no lines on the epoxy resin! 0.5 mm,
A good circuit with a distance between lines of 0.5 mm could be formed with high precision. The conductivity of this circuit was 40Ω/□, and the adhesive strength was also good.

〔Effect of the invention〕

As explained above, according to the circuit transfer body and transfer method according to the present invention, a circuit pattern of conductive paint is printed by a printing means such as screen printing or gravure printing,
Since a circuit is formed by transferring this circuit pattern onto a transfer target, it is possible to form a circuit without requiring expensive or special equipment or wasting conductive materials. There is an advantage. Furthermore, unlike traditional transfer methods, there is no need to take into account breakage, making it possible to increase the thickness of the lines that make up the circuit pattern. It becomes possible to reduce the amount of conductive particles packed. Therefore, there is an advantage that it is possible to manufacture a circuit having good adhesion and desired conductivity.

Furthermore, according to the circuit transfer body of the present invention, a prepreg layer made of a base material impregnated with a synthetic resin and semi-cured is provided on the circuit pattern, and the circuit pattern is transferred to the transfer target via the prepreg layer. Since circuits are formed by doing this, there is also the advantage that circuits can be formed on thermosetting resins or wooden boards with rough surfaces, which were previously impossible or difficult to transfer.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a specific example of a circuit transfer body according to the present invention. 1...Support film, 2...Circuit pattern, 3...
- Prepreg layer, 4... Transferred object. Applicant's agent Masaaki Amemiya Procedural amendment (Volunteer Showa Ship July 2, 1999)

Claims (2)

[Claims] (1) A conductive paint that is basically made by adding 100 to 500 parts by weight of non-metallic conductive particles to 100 parts by weight of resin on the support film, and has easy peelability when heated and pressurized from the support film. A circuit transfer body characterized in that a circuit pattern having a surface resistance of 50Ω/□ or less is printed, and a semi-cured prepreg layer made by impregnating a base material with a synthetic resin is laminated on the circuit pattern. (2) A conductive paint that is basically made by adding 100 to 500 parts by weight of non-metallic conductive particles to 100 parts by weight of resin on the support film, and has easy peelability when heated and pressurized from the support film. A circuit transfer body is printed with a circuit pattern having a surface resistance of 50 Ω/□ or less as shown in FIG. Laminated so as to be in close contact with the transfer target, temperature 80~250℃, pressure 5~10℃.
A circuit transfer method, characterized in that the circuit pattern is transferred at the same time as heat and pressure is applied at Kg/cm^2 to bond the transfer target and the prepreg layer.