JPS62244192A - Circuit transcription foil and method of transcription - 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 foil and a transfer method, and more specifically, to a circuit printed on a support film by a printing method such as screen printing, and provided with a metal plating layer, which is the main conductive part. ,
The present invention relates to a circuit transfer foil and a transfer method that enable easy production of wiring boards with good conductivity by transferring this onto an object to be transferred.

[Technical background of the invention]

Conventionally, as a method for transferring electrical circuits such as wiring boards, a conductive thin film is formed over the entire surface of a support film, laminated onto the object to be transferred, and heat is applied to heat and press only the circuit portion (transfer portion). A method of forming a circuit by transferring only the circuit portion onto an object using a board (Japanese Unexamined Patent Application Publication No. 1983-1999)
No. 141789) is known.

According to such a circuit transfer method, (1) a heating plate that can heat and press only a predetermined portion is required, and the person performing the circuit transfer must purchase said heating plate; (2) the conductive thin film other than the transferred portion is Since the material will be discarded, the material will be wasted and the cost will be high. ■Because the circuit pattern is transferred by heating and pressurizing only the predetermined area using the heating plate, the conductive thin film has a good cut. There were disadvantages such as the need to be present.

This breakage 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.On the other hand, in order to obtain good conductivity, If the amount of conductive particles is increased, the adhesion of the conductive thin film tends to deteriorate, resulting in the disadvantage that it is difficult to manufacture circuits with good conductivity and excellent adhesive strength. Was.

In order to eliminate such drawbacks, the present inventor applied conductive paint onto a support film by screen printing, gravure printing,
Developed a circuit transfer foil and a circuit transfer method that can transfer a circuit with good conductivity by printing circuit bars and turns in advance by offset printing or Kumbo printing and transferring this circuit pattern to a transfer target, and filed a patent application. (Japanese Patent Application No. 117264/1984, etc.).

According to such a method, it is possible to easily transfer a circuit having better conductivity than a conventional electric circuit using conductive resin as a conductive part without requiring special equipment. There is an advantage. However, since the conductive part is a conductive resin layer, even if we pursue good conductivity, it will naturally be limited, and compared to metal electric circuits, the disadvantage is that the conductivity is inferior. It was extremely difficult.

[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 foil and a circuit transfer method that can form a circuit having good conductivity similar to that of metal.

Therefore, the circuit transfer foil according to the present invention contains 300 to 1 part of conductive particles per 100 parts by weight of resin on the support film.
000 parts by weight of the basic conductive paint is used to print a circuit pattern that exhibits easy peelability immediately after heating and pressurizing the support film, then providing a metal plating layer on the circuit pattern, and further adding at least the metal. It is characterized in that an adhesive layer is laminated on the top surface of the plating layer.

Further, in the circuit transfer method according to the present invention, 300 to 10 parts of conductive particles are added to 100 parts by weight of resin on the support film.
00 parts by weight of a conductive paint is used to print a circuit pattern that exhibits easy peelability immediately after heat processing with the support film, and then a metal plating layer is provided on the circuit pattern, and at least the metal A circuit transfer foil with an adhesive layer laminated on the top surface of the plating layer is laminated so that the adhesive layer is in close contact with the transfer target, and heated and pressed at a temperature of 80 to 250°C and a pressure of 5 to 10 Kg/cm. This method is characterized in that a circuit pattern having a metal plating layer is transferred onto a transfer target.

In the circuit transfer foil and circuit transfer method according to the present invention, a circuit pattern is printed with a conductive paint using a printing method such as screen printing or gravure printing, and a metal plating layer is further formed on the circuit pattern to make it conductive. In order to transfer this metal plating layer to the transfer target, an adhesive layer is formed, which makes it possible to avoid waste of materials and to transfer the circuit onto the transfer target without the need for expensive equipment. Furthermore, since the metal plating layer is used as a conductive part, it has the advantage that conductivity similar to that of metal can be obtained.

[Detailed description of the invention]

The circuit transfer foil according to the present invention has the following features as shown in FIG. On the support film 1, a conductive paint that shows easy peelability immediately after heating and pressurizing the support film 1 is printed in a desired circuit shape to form a circuit pattern 2, and further, a metal plating N3 is laminated on this circuit pattern 2. At the same time, the metal plating layer 3
It has a structure in which an adhesive layer 4 is provided so as to cover the circuit pattern 2 in which the circuit patterns 2 are laminated. In this embodiment, the adhesive layer 4 is formed so as to cover the entire surface of the support film 1, but since this adhesive N4 is for transferring and adhering the circuit pattern 2 to the object to be transferred, It is clear that it is sufficient if the circuit pattern 2 can be bonded. For this reason, it may be provided, for example, in a laminated manner only on the metal plating layer 3. In this case, like the circuit pattern 2 made of conductive paint, the adhesive layer 4 is provided only on the metal plating layer 3 by printing technology.

The support film 1 on which the circuit pattern 2 is formed by conductive paint is not fundamentally limited in the present invention, and has good adhesion to the circuit pattern 2 at room temperature and is easily bonded to the circuit pattern 2 immediately after heating and pressing. A synthetic resin film or the like which is heat resistant and smooth and 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 film, and silicone-treated release paper.

The conductive paint used to print the desired circuit pattern 2 on the support film 1 described above coats the circuit pattern 2 with a metal plating layer 3.
It is necessary to contain an appropriate amount of metal powder to enable selective layering.

That is, for example, in an electroless plating tank, when the support film 1 on which the circuit pattern 2 is printed is immersed, the conductivity and surface are such that metal ions selectively and well deposit and adhere to the circuit pattern 2. Preferably, it has a state. Furthermore, it is possible to print a good and fine circuit pattern on the support film 1, and in addition, various aspects such as basic performance as a transfer body, such as good peeling from the support film 1 immediately after heating and pressurization, etc. It is necessary that the following conditions are met.

In order to satisfy these conditions, the support film, the resin liquid (solvent and solute) that is the base material of the conductive paint,
Furthermore, it is important to select the type of conductive particles to be added to this resin liquid, and it is also necessary to consider the amount and particle size of the conductive particles. The resin serving as the base material for such a conductive paint is a resin component (solute) that has adhesive properties with the support film 1 at room temperature and can form an easily peelable circuit pattern immediately after heating and pressing, such as an acrylic resin. , polyamide-based, epoxy-based, polyether-based, polyester-based resin, etc., or one or more of cyclized rubber, chlorinated rubber, rosin, etc., for example, -EK SMTB)[,
Ketone solvents such as cyclohexanone, aromatic hydrocarbon solvents such as toluene and xylene, alcohol solvents such as IPA and butanol, ether solvents, ester solvents, and other types of solvents such as DMF SN-methylpyrrolidone. It can be a resin solution dissolved in the above.

The conductive particles added to the resin solution mentioned above are basically in accordance with the present invention, as long as they can be uniformly dispersed in the resin solution, can impart good conductivity, and can form the metal plating layer 3 well. It is not limited to. For example, it can be one or more of metal particles such as gold, silver, platinum, copper, nickel, aluminum, tin, and zinc, or composites and alloy powders whose surfaces are coated with the above metals.

Such conductive particles are used in an amount of 300 parts by weight per 100 parts by weight of resin.
Add ~1000 parts by weight. If the amount is less than 300 parts by weight, the metal density of the circuit pattern 2 may be too low and metal ions may not be selectively deposited on the circuit pattern 2. On the other hand, if it exceeds 1000 parts by weight, the metal ions may not be deposited uniformly on the circuit pattern 2. It easily accumulates, but the paint film becomes brittle.

The average particle size of the conductive particles is preferably 10 μm or less. This is because if the thickness exceeds 10 μm, problems tend to occur 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 10 to 50 μm.

If the thickness of the 4-electroconductive paint is less than 10 μm, good conductivity cannot be obtained, while if it exceeds 50 μm, there is a risk that it will be difficult to print a circuit board by screen printing or the like.

Naturally, it is preferable that the line width or the distance between lines of the circuit pattern 2 be small. In the circuit transfer foil according to the present invention, in order to make it possible to form a circuit with the above-mentioned line width or distance between lines of 1 mm or less, the viscosity of the conductive paint to be printed is set to 10 to 1000 poise, most preferably 10 to 400 poise.
It is preferable to adjust to poise. If the viscosity of the conductive paint is less than 10 poise, there is a risk that the wire will lose its shape and the circuit will be shorted, while if it exceeds 1000 poise, it will be difficult to print the circuit pattern on the support film 1. .

In the circuit transfer foil according to the present invention, as described above, a metal plating layer 3 is further provided on the circuit pattern 2 made of the conductive paint. This metal plating layer 3 constitutes the main body of the conductive part, and therefore is preferably made of a metal with good conductivity.

In addition, since it is formed by plating on the circuit pattern 2 described above, it is desirable that the circuit pattern 2 drawn with the conductive paint can be well plated. The plating property of a given metal is generally considered to be determined by the resin that is the base material of the conductive paint, the type and amount of conductive particles added to the conductive paint, the type of the support film 1, and the like. The metal plating layer 37 that satisfies these various conditions includes, for example, Cu, Ni, Sn,
Examples include Ag, 80, and pt.

The thickness of this metal plating layer 3 is preferably 3 to 20 μm.
It is good to be. This is because if it is less than 3 μm, the environmental stability of the plating will be poor and it will easily deteriorate.

Furthermore, it is not economically advisable to form plated eyebrows with a thickness exceeding 20 μm.

In the circuit transfer foil according to the present invention, an adhesive layer 4 is provided on the metal plating layer 3 described above or on the entire support film 1 including the metal plating layer 3.

As shown in FIG. 1, when the adhesive layer 4 is provided by burying the circuit pattern 2 and the metal plating layer 3, this adhesive layer 4 also functions as an oxidation-preventing film for the metal plating layer 3. . Therefore, there is an advantage that a metal that is easily oxidized, such as copper, can be used without any problem as the metal of the metal plating layer 3.

Such an adhesive layer 4 is prepared under the circuit transfer conditions (pressure = 5 to
10Kg/cn! , temperature: 80 to 250°C), and the circuit pattern 2 of the conductive paint adheres to the transfer target at a temperature of 80 to 250°C
Also, an adhesive that does not attack the metal plating film 3 is used. As such an adhesive 4, for example, a hot-melt adhesive that melts near the transfer temperature and a thermosetting resin added thereto to make it into a semi-cured state can be effectively used. Specific examples of such adhesives include olefin-based, polyester-based, acrylic-based, urethane-based,
In addition to rubber adhesives, ethylene-vinyl acetate copolymer (
EVA'), saponified EVA, vinyl chloride-vinyl acetate copolymer, and the like can be used.

The modifiers added to the above-mentioned hot-melt adhesives are mainly added to improve the adhesive strength and heat resistance after bonding, and such modifiers include, for example, styrene resin. , coumaron indene resin, phenol resin, diarytupthalate, epoxy, etc. can be used.

Further, the thickness of this adhesive layer 4 is preferably 1 to 10 μm.
It is better to be m. If it is less than 1 μm, there is a risk that it will not adhere to the object to be transferred with good adhesive strength, while if it exceeds 10 μm, it is unnecessary, and if it is extremely thick, there is a risk that the transferability will be impaired.

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

According to the circuit transfer method according to the present invention, first, the surface of the circuit transfer foil on which the adhesive layer 4 is provided is brought into contact with the transfer target portion of the transfer target, and the metal film on the support film 1 is heated and pressed. - Transfer the laminated circuit pattern 2 of 7 layers 3 to the transfer target.

Any object may be used as such a transfer object as long as the adhesive layer 4 can be well bonded thereto.

For example, general-purpose plastics such as polyethylene, polypropylene, polystyrene (including AS resin and ABS resin), polyvinyl chloride, and polyacrylic resin, polyacetal, polyamide, polycarbonate, polyphenylene oxide resin, and saturated polyester resin (PUT
, PBT), high-performance engineering plastics such as polyphenylene sulfide, polysulfone, aromatic polyester, polyarylate, polyetheretherketone, polyetherimide, polyaminobisamide, polyallylsulfone, polyamideimide,
It can be a super heat-resistant engineering plastic such as polyimide, polybismaleimide, or triazine resin.

The heating and pressurizing method is not limited in the present invention, and various means can be used. for example,
Transfer can be performed by heating and pressing using a heat roll, heat press, etc.

When transferring the laminated circuit pattern 2 of the metal plating 3 via the adhesive layer 4, at a temperature of 80 to 250°C,
Transfer with a pressure of 5 to 10 kg/cot. Transfer temperature is 8
If it is lower than 0°C, there is a possibility that the circuit pattern formed on the circuit transfer foil will not be transferred, and if it is higher than 250°C, there is a possibility that warping, thermal shrinkage, thermal deterioration, etc. will occur in the transferred object.

Also, if the transfer pressure is less than 5 Kg/c++1,
There is a risk that the circuit pattern may not be transferred well;
This is because if it is larger than Kg/cnl, there is a risk that the circuit pattern 2 will collapse.

As described above, after transferring the circuit pattern 2 on which the metal plating layer 3 is laminated to the transferred object 5 via the adhesive layer 4, the support film 1 is peeled off and a circuit is formed on the transferred object (first step). (See Figure 2).

The electric circuit formed as described above may be made into a circuit by connecting terminals to conductive paint exposed on the surface, for example.

In this case, the current passes through the conductive paint layer 2 and the metal plating layer 3.
The current flows through the metal plating layer 3.

Therefore, it is possible to create a circuit that is substantially similar in conductivity to a metal circuit.

In addition, if it is determined that the conductivity of the conductive paint layer 2 is extremely low and the resistance when current flows from the conductive paint layer 2 to the metal plating layer 3 is large, the conductive paint layer 2 at the terminal portion is peeled off. However, it is also possible to connect terminals directly to the metal plating layer 3 to form an electric circuit.

Example A conductive paint (with the following composition) was applied on the polyester film.
A circuit pattern was printed with a line width of 0.8 mm, a line-to-line distance of 0.8 mm, and a thickness of 25 μm.

Composition 1 Thermoplastic urethane resin 100 parts by weight Ester and ketone solvents 180 parts by weight Silver-coated copper particles 500 parts by weight A metal plating layer was laminated to a thickness of 5 μm by electroless plating on the circuit pattern thus produced. An adhesive layer having the following composition was formed by coating to obtain a circuit transfer foil.

Composition 2 Polyamide resin 60 parts by weight Epoxy resin 40 parts by weight This circuit transfer foil was brought into close contact with a transfer target made of ABS resin, and the circuit was transferred at a temperature of 190°C and a pressure of 8 kg/crA. Line width 0.8 m on ABS resin
A good circuit with a line width of 1i1t of 0.8 mm was formed with high accuracy. The conductivity of this circuit is 0.1Ω/cnf
The adhesive strength was also good.

〔Effect of the invention〕

As explained above, according to the circuit transfer foil and transfer method according to the present invention, a circuit pattern of conductive paint is printed by printing means such as screen printing or gravure printing,
A circuit is formed by further forming a metal plating layer on this circuit pattern, as well as an adhesive layer and transferring this to the transfer target, so it is possible to form a circuit with the same conductivity as a metal circuit by transfer. It has the advantage of becoming Another advantage is that a circuit can be formed without requiring expensive or special equipment and without wasting conductive materials.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a specific example of a circuit transfer foil according to the present invention, and FIG. 2 is a sectional view showing a circuit transferred to a transfer target. 1...Support film, 2...Circuit pattern, 3...
・Metal plating layer, 4...adhesive layer, 5...transferred object

Claims (2)

[Claims] (1) A conductive paint that is basically made by adding 300 to 1000 parts by weight of conductive particles to 100 parts by weight of resin on a support film, and exhibits easy peelability immediately after heating and pressurizing the support film. A circuit transfer foil characterized in that a circuit pattern is printed, a metal plating layer is provided on the circuit pattern, and an adhesive layer is further laminated on at least the top surface of the metal plating layer. (2) A conductive paint that is basically made by adding 300 to 1000 parts by weight of conductive particles to 100 parts by weight of resin on a support film, and exhibits easy peelability immediately after heating and pressurizing the support film. A circuit pattern is printed, and then a metal plating layer is provided on the circuit pattern, and a circuit transfer foil having an adhesive layer laminated on at least the upper surface of the metal plating layer is laminated so that the adhesive layer is in close contact with the transferred object. A circuit transfer method characterized in that the circuit pattern having the metal plating layer is transferred onto a transfer target by heating and pressing at a temperature of 80 to 250° C. and a pressure of 5 to 10 kg/cm^2.