JPS61276292A - 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 copper thin film on a wiring board substrate, laminating a mask in the shape of a circuit pattern, and chemically etching the #JiJ thin film to form a circuit. (2) A method using special plating that only applies plating to the circuit part; (2) A method in which a conductive thin film is formed over the entire surface of the support film, and is laminated to the transfer target, while the circuit part (transfer A method of forming a circuit by transferring only the circuit part onto the object using a heating plate that can heat and press only the circuit part (Japanese Unexamined Patent Publication No. 55-1
41789) are known.

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. This has the drawback of wasting materials and making it expensive, and when chemically etching a thin copper film with nitric acid, the copper edges of the masked circuit parts are slightly dissolved. There is also a drawback.

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 difficult to increase the thickness of the conductive thin film. Increasing the amount of conductive particles tends to deteriorate the adhesion of the conductive thin film, which also has the disadvantage of making it difficult to manufacture circuits with good conductivity and excellent adhesive strength. Ta.

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. Moreover, it is an object of the present invention to provide a circuit transfer body and a circuit transfer method that can form a circuit having good conductivity and adhesive strength, and can also be transferred to various non-transfer materials, such as thermosetting resin or wood. .

Therefore, in the circuit transfer body according to the present invention, 500 parts by weight of metal conductive particles are added to 100 parts by weight of the resin on the support film.
A basic conductive paint with the addition of ~1000 parts by weight,
A prepreg layer is printed with a circuit pattern having a surface resistance of 1 Ω/□ or less, which shows easy peelability when heated and pressurized from the support film, and on this circuit pattern, the base material is impregnated with a synthetic resin and brought into a semi-cured state. It is characterized by being laminated.

Further, in the circuit transfer method according to the present invention, 500 to 500 parts by weight of metal conductive particles are added to 100 parts by weight of resin on the support film.
A circuit pattern with a surface resistance of 1 Ω/□ 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 1000 parts by weight, and furthermore, on this circuit pattern, J A circuit transfer body in which semi-cured prepreg layers are laminated by impregnating a base material with a synthetic resin is laminated so that the prepreg layer is in close contact with the transfer target, and the circuit transfer body is heated at a temperature of 8.
Heat and pressurize at 0 to 250°C and a pressure of 5 to 10 kg/ad,
The present invention is characterized in that the circuit pattern is transferred at the same time as the transfer target body and the prepreg layer are bonded together by thermocompression.

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 using rollers, 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 needs to have the conductivity required for a circuit having a conductive path filled with metal conductive particles, that is, a surface resistance of 1 Ω/□ 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 normal temperature properties.
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 used to print 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 (1Ω/□ 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 having sufficient strength for the prepreg layer 3 to be cured without destroying the circuit pattern 2. It is necessary to satisfy various conditions such as adhesion.

In order to satisfy these conditions, the support film and the resin solution (solvent and solute) that is the base material of the conductive paint must be
Furthermore, it is important to select the type of metal conductive particles to be added to this resin solution, and it is also necessary to consider the amount and particle size of the metal conductive particles. The resin solution that serves 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-based resin solution. , vinyl chloride-based, urethane-based, polyester-based resins, etc., or one or more of cyclized rubber, chlorinated rubber, rosin, etc., for example, MEK, MIBK, ketone-based solvents such as cyclohexanone, aromatic solvents such as toluene and xylene, IPA, etc. .

It can be a resin solution dissolved in one or more of alcohol solvents such as butanol, ether solvents, ester solvents, and the like. - The metal 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 solution and impart good conductivity. For example, gold,
It is possible to use one or more types of metal particles such as silver, platinum, copper, nickel, and aluminum, or a surface coating composite whose surface is coated with the metal.

Such metal conductive particles are added in an amount of 500 to 1000 parts by weight per 100 parts by weight of the resin. If it is less than 500 parts by weight, it will be difficult to achieve a surface resistance of 1Ω/□ or less, which is required for such a circuit filled with metal conductive particles, while if it exceeds 1000 parts by weight, sufficient adhesiveness will not be achieved. There is a risk that it will disappear.

The average particle size of the metal conductive particles is preferably 10 μm or less. This is because if it exceeds 10 μm, it will be disadvantageous during screen printing.

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 20 to 50 μm.

If the thickness of the conductive paint is less than 20 μm, in order to obtain the above-mentioned conductivity of 1Ω/□ or less, it is necessary to fill it with a large amount of metal 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 metal 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 metal conductive particles filled, which improves the adhesive strength of the transferred circuit and improves the adhesive strength compared to conventional transfer methods. Accuracy is also improved.

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 i n+m or less, the thickness of the lines is increased (to obtain good conductivity), and good adhesion is achieved. In order to form a strong circuit, the viscosity of the conductive paint to be printed is set to 10 to 2.
It is preferable to adjust to 00 poise. If the viscosity of the conductive paint is less than 10 voids, there is a risk that the wires will be distorted and the circuit will be short-circuited, while if it exceeds 200 voids, 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 a 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 7% 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 transfer target, while if it exceeds 70% by volume, there will be no problem with interlayer adhesion, but it will be difficult to manufacture prepregs with more than 70% by volume. It is.

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, ABS SAS.

The material may be a thermoplastic resin such as HIPS, polyacetal, vinyl chloride, nylon, polycarbonate, or polyethylene, a thermosetting resin such as polyimide resin, epoxy resin, phenol resin, or polyester resin, or a wooden board. According to the circuit transfer member according to the present invention, unlike conventional transfer methods, it is possible to transfer onto a thermosetting resin or a wooden board having a rough surface, which has been difficult in the past.

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/cd. 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.

Also, the transfer pressure is 5Kg/c! If it is smaller than li, there is a risk that the circuit pattern will not be transferred well;
This is because if it is larger than cd, 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 poise) was used on a silicone-treated release film, line width 0°8 mm,
A circuit pattern was printed with a line distance of 0.8 mm and a thickness of 25 μm.

Composition Acrylic resin 100 parts by weight Ester and ketone solvents 100 parts by weight Silver-coated copper particles 850 parts by weight (average particle size 2
μm) DAP on the paper on the circuit pattern printed as described above.
A circuit transfer body was obtained by impregnating a resin and laminating prepregs in a semi-cured state (hardened by about 20 to 40%).

The prepreg layer of the circuit transfer body manufactured in this way is brought into close contact with the transfer target made of polyester resin, and
When a circuit pattern was transferred at a temperature of 30°C and a pressure of 8 kg/cal, the line width was 0.8 on the epoxy resin.
A good circuit with a thickness of 22 μm and a line distance of 0.8 mm was formed with high accuracy. The conductivity of this circuit is 0.7
Ω/□, 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 to a transfer target, there is no need for expensive or special equipment, and there is no need to waste conductive materials (it is possible to form a circuit). In addition, unlike traditional transfer methods, there is no need to consider sharpness, making it possible to increase the thickness of the lines that make up the circuit pattern, thereby achieving the desired conductivity. It is possible to reduce the amount of metal conductive particles to be filled in order to obtain the desired conductivity.Therefore, there is also the 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 Masashi Amemiya Written amendment of procedure (July 2nd, 1947)

Claims (2)

[Claims] (1) A conductive paint that is basically made by adding 500 to 1000 parts by weight of metal conductive particles to 100 parts by weight of resin on a support film, and exhibits 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 1Ω/□ 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 500 to 1000 parts by weight of metal conductive particles to 100 parts by weight of resin on the support film, and exhibits easy peelability when heated and pressurized from the support film. A circuit transfer body is formed by printing a circuit pattern with a surface resistance of 1 Ω/□ or less, and then laminating a semi-cured prepreg layer on the circuit pattern by impregnating the base material with a synthetic resin. Laminated so as to be in close contact with the transfer body, temperature 80-250℃, pressure 5-10K
A circuit transfer method, characterized in that the circuit pattern is transferred at the same time as heat and pressure is applied at g/cm^2 to thermally press the transfer target and the prepreg layer.