JPS63244786A - Conductive circuit and manufacture of the same - 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 conductive circuit and a method for manufacturing the same, and more particularly, a conductive circuit formed with good adhesion to a resin molded product and a method for manufacturing the conductive circuit. Regarding. In particular, the present invention relates to a conductive circuit in which a circuit with good adhesiveness is formed at the same time as the molded product is molded into a polyolefin resin molded product, and a method for manufacturing the same.

[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. If the amount of particles is increased, the adhesion of the conductive thin film will deteriorate and it will tend to become brittle, making it difficult to manufacture circuits with good conductivity and adhesive strength. was occurring.

In order to eliminate such drawbacks, the present inventor applied conductive paint onto a support film by screen printing, gravure printing,
A circuit transfer foil with a circuit pattern printed in advance by off-cent printing or tampo printing is placed in a mold,
We developed a transfer foil that transfers the circuit at the same time as molding the transfer target by injection molding, and filed a patent application (Japanese Patent Application No. 134649/1984, etc.).

According to such a method, it has better conductivity compared to an electric circuit that uses a conventional conductive resin as a conductive part,
Another advantage is that a circuit with excellent adhesive strength can be formed at the same time as the transfer target is molded.

However, the material to be transferred is ABS.

polysecure, polysulfan, ppo, modified PP
It has the drawback that it is limited to resins that have good adhesion to the resin constituting the circuit, such as O, polycarbonate, and old PS1, and that it is difficult to use polyolefin resins that are inexpensive and have good insulation properties. Such polyolefin resins, especially when used as circuit boards, have the advantage of good heat resistance, allowing the use of solder to connect circuits, and are also extremely inexpensive compared to heat-resistant engineering plastics. Therefore, the use of the above-mentioned polyolefin resin is desired.

[Summary of the invention]

The present invention was made in view of the above points, and an object of the present invention is to provide a conductive circuit formed with good adhesive strength on a polyolefin resin molded product having particularly poor adhesive properties, and a method for manufacturing the conductive circuit. That is.

Therefore, in the conductive circuit according to the present invention, 300 to 100 parts of conductive particles are added to 100 parts by weight of resin in a resin molded product.
0 parts by weight of a conductive circuit body is provided by transfer, the conductive circuit body having RR' S
iYg (In the above general formula, R is a monovalent olefinic unsaturated hydrocarbon group or a hydrocarbonoxy group, each Y
is a hydrolyzable organic group, and R' is an R group or a Y group). It is characterized in that the interface with the product is crosslinked with water and a condensation catalyst.

Further, in the method for manufacturing a conductive circuit according to the present invention, 300 parts by weight of conductive particles are added to 100 parts by weight of resin on a support film.
~1000 parts by weight, RR' SiYg (In the above general formula, R is a monovalent olefinic unsaturated hydrocarbon group or a hydrocarbonoxy group, each Y is a hydrolyzable organic group, R'' is an R group or a Y group A conductive paint containing 0.5 to 50 parts by weight of an organic silane cuff pulling agent shown in A circuit transfer foil with a circuit pattern printed thereon is placed on the inner wall of an injection mold for molding a resin molded product so that the support film is in contact with the inner wall of the mold, and the molten resin is press-fitted into the mold to form the resin. The product is characterized in that after the product is molded and the support film is peeled off, it is immersed in water containing a silanol condensation catalyst to cause a crosslinking reaction.

In the present invention, the conductive paint is crosslinked to form the conductive circuit body, and a crosslinking reaction is also caused at the interface between the resin molded article to be transferred and a crosslinked portion is formed. This results in a conductive circuit with good adhesive strength. Further, according to the method for manufacturing a conductive circuit according to the present invention, a circuit pattern is printed on a circuit pattern for injection molding using a conductive paint containing a special organic silane coupling agent. In order to transfer the circuit and graft the silane coupling agent at the same time as injection molding of this molded article, a conductive circuit having a crosslinked portion not only in the conductive circuit body but also at the interface with the molded article. can be formed.

[Detailed description of the invention]

As shown in FIG. 1, the conductive circuit according to the present invention has a crosslinked conductive circuit main body 2 formed on a resin molded product 1.

The bonding state of this resin molded product 1 and the conductive circuit body 2 is
Schematically shown in the figure.

As is clear from this figure, the conductive circuit main body 2 has graft branches 3 of a silane coupling agent grafted to the resin constituting the main body 2. Furthermore, the graft branches 3 are in a mutually crosslinked state. Furthermore, graft branches 3 are also formed on the resin molded article 1 due to the organic silane cambric agent diffused during the injection molding process. Therefore, a bridge portion 4 is formed between the conductive circuit body 2 and the graft branch 3 formed on the conductive circuit body 2, and a strong bond is obtained between the circuit body 2 and the resin molded product 1.

The organic silane coupling agent is diffused into the molten resin by the heat and pressure of the molten resin during injection molding, rather than the conductive paint that forms a conductive circuit during injection molding, so it is difficult to diffuse deep into the molten resin. Have difficulty. Therefore, the bridge portion 4 is formed only near the interface 5 between the resin molded product 1 and the conductive circuit main body 2. This bridge portion 4 can ensure sufficient adhesive strength only at the interface portion 5.

To manufacture such a conductive circuit according to the present invention, first, 300 to 1000 parts by weight of conductive particles and RR'SiY2 (
In the above general formula, R is a monovalent olefinically unsaturated hydrocarbon group or a hydrocarbonoxy group, each Y is a hydrolyzable organic group, and R' is an R group or a Y group. A circuit transfer printed with a circuit pattern that is easily removable from the support film immediately after heating and pressing, using a conductive paint containing 0.5 to 50 parts by weight of a ring agent and an organic peroxide for generating free radicals. Prepare foil.

A cross-sectional view of one configuration example of this circuit transfer foil is shown in FIG.

The support film 6 on which the circuit pattern 7 is formed by the conductive paint is not fundamentally limited in the present invention, and has good adhesion to the circuit pattern at room temperature and is easily bonded to the circuit pattern immediately after heating and pressurizing. A synthetic resin film that is peelable from the circuit pattern, has heat resistance and normal temperature properties, and is not attacked by the solvent contained in the conductive paint can be effectively used. Specific examples of the support film 6 include plastic films such as polyester films, polyimide films, and polypropylene films, and aluminum foil.

The conductive paint for printing the desired circuit pattern 7 on the support film 6 described above must be capable of printing a good and fine circuit pattern 7 on the support film 6, and, in addition, have basic performance as a transfer foil. For example, it is necessary to satisfy various conditions such as good peeling from the support film 6 immediately after heating and pressing.

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 6 at room temperature and can form an easily peelable circuit pattern immediately after heating and pressurizing, 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, MEK, MIBK,
One or more of the following: ketone solvents such as cyclohexanone, aromatic hydrocarbon solvents such as toluene and xylene, alcohol solvents such as rPA and butanol, ether solvents, ester solvents, and other solvents such as DMF and N-methylpyrrolidone. It can be a resin solution dissolved in.

The 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, silver, platinum, copper, nickel, aluminum,
The material may be metal particles such as tin or zinc, or one or more of the above-mentioned composites and alloy powders whose surfaces are coated with metals, or conductive particles such as carbon black.

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 it is less than 300 parts by weight, the density of the conductive particles in the circuit pattern may be too low to exhibit good conductivity, while if it exceeds 1000 parts by weight, there is a risk that the adhesive strength will deteriorate.

The average particle diameter of the conductive particles is preferably 10 crm or less; if it exceeds 10 μm, there is a possibility that the circuit pattern 7 cannot be printed by printing means such as screen printing.

The conductive paint has the following general formula: % formula % (1) (wherein, R is a monovalent olefinic unsaturated hydrocarbon group or a hydrocarbonoxy group, and each Y is a hydrolyzable organic group, R' is an R group or a Y group). Such an organic silane coupling agent causes a grafting reaction at the interface between the conductive circuit main body 2 and the molded product 1 when injection molding the molded product of the polyolefin resin, and causes a grafting reaction between the transferred body and the conductive circuit. It has the effect of improving the adhesive strength between the two. Furthermore, this organosilane coupling agent is used in the conductive circuit body 1.
Since a cross-linking reaction occurs between the conductive particles and the conductive particles are immobilized, there is also the advantage of improving the wet heat cycle and heat cycle of the circuit.

Examples of R in such an organic silane coupling agent include vinyl, allyl, butenyl, cyclohexenyl,
Cyclopentadienyl, CIlg = CCCH3) C
OO(CIlg) a-1CHS C(Clh
) C00CHt CH* 0 (C11
g) a- and Cn*-C(C1ls)COOCHtcHtOc
II tcHcHto (Cllt ) 3-H, with vinyl groups being preferred.

Further, as Y, an alkoxy group such as methoxy, ethoxy and butoxy, an acyloxy group such as formyloxy, acetoxy or probionoxy, or a
N=C(C113)! , -0N=CCH3C*Hs
Any hydrolyzable group such as oxime groups such as -0N=C(C6Hs) or -NHCIIa, alkynoamino groups such as Examples include organic groups that contain water.

The organic silane coupling agent is preferably added in an amount of 0.5 to 50 parts by weight per 100 parts by weight of the resin.

o, s If it is less than 1 part by weight, there is a risk that the adhesive strength between the transfer target and the conductive circuit will not improve, while if it exceeds 50 parts by weight, the conductive circuit will be greatly modified and become too brittle. This is because it may cause a risk.

Furthermore, organic peroxides for generating free radicals in such conductive paints include, for example, benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, 2.5- Ji(
peroxybenzoate) hexyne-3,1,3-bis(tert-butyl-peroxyisopropyl)benzene, lauroyl peroxide, tert-butylberacetate, 2,5
-dimethyl 2,5-di(tert-butylperoxy)hexane 3.2,5-dimethyl 2,5-di(tert-butylperoxy)hexane and tert-butylperoxybenzoate, Ab compounds such as 'azobis-isobutyronitrile , dimethyl isobutyrate, and the like.

The organic peroxide for generating such free radicals is preferably used in an amount of 0.05 to 0.2 parts by weight based on 100 parts by weight of the resin. If the amount of organic peroxide is less than 0.05 parts by weight, there is a risk that sufficient free radicals will not be generated to cause a grafting reaction, while if it exceeds 0.75 parts by weight, too much crosslinking reaction will occur. This is because the formed circuit may become brittle. Although the circuit pattern 7 is printed on the easily peelable support film 6 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 6 by:
It is preferable to print to a thickness of 15 to 40 μm.

If the thickness of the conductive paint is less than 15 μm, good conductivity cannot be obtained, while if it exceeds 40 μm, printing a circuit pattern by screen printing or the like may become difficult.

It goes without saying that it is preferable that the line width or the distance between lines of the circuit pattern 7 be narrower. In the circuit transfer foil used in the present invention, the viscosity of the conductive paint to be printed is set to 10 to 1000 points, most preferably 10 to 40
It is preferable to adjust the viscosity to 0 voids. If the viscosity of the conductive paint is less than 10 voids, there is a risk that the wires will lose their shape and the circuit will be short-circuited. On the other hand, if it exceeds 1000 voids, the circuit pattern will be damaged by the support film 6. This is because it becomes difficult to print on top.

When manufacturing a conductive circuit using such a circuit transfer foil for injection molding, the supporting film 6 is brought into contact with the inner wall of the mold 8a of one mold 8a of the injection mold 8 for use in resin molding. Place the mold 8b over the mold 8a,
Molten resin 10 is injected through a resin injection port 9 to manufacture the molded product 1 and simultaneously transfer the circuit.

At this time, some amount of the organic silane coupling agent and organic peroxide contained in the circuit pattern 7 migrate into the molten resin 10 due to the pressure and heat of injection molding. The organic peroxide contained in the circuit pattern 7 is decomposed by the heat of the molten resin 10 and forms free radicals in the molten resin 10 and the resin constituting the circuit pattern 7,
An organic silane coupling agent is grafted to form graft branches 3. That is, at least at the interface between the circuit pattern 7 and the molded article 1, there is a large amount of resin grafted with the silane coupling agent.

In the method of forming a circuit simultaneously with injection molding as described above, the pressure and temperature within the injection mold 8 are particularly important. That is, when the pressure inside the mold is small, the circuit of the circuit transfer foil is not transferred well, and the support film 6
When it is peeled off, there is a possibility that a part of it will remain on the support film 6, and when the pressure inside the mold is large, there is a possibility that the drawn circuit will collapse.

The pressure inside the mold is preferably 200 to 1000K.
g/-. The pressure inside the mold can be controlled by the viscosity of the molten resin injected into the mold 8 and the injection pressure.

If the viscosity of the molten resin is too high, uneven pressure will be applied to the circuit transfer foil, and the areas with low pressure load will be applied to the support film 6.
There is a risk that the injection pressure will remain, and the injection pressure will also increase, so there is a risk that the circuit will be damaged. If the viscosity is too low, the applied pressure will be relatively small, making it difficult to transfer the circuit on the circuit transfer foil. Taking this into consideration, the viscosity of the resin for producing the molded article 1 when injected into the injection mold 8 is preferably 10 3 to 10 5 poise. If the above-mentioned viscosity is less than 103 poise, the pressure load on the circuit transfer foil will be small, and there is a risk that good transfer will not be performed.On the other hand, if it exceeds 105 poise, the pressure load will become uneven, resulting in poor transfer. There is a risk of producing defective parts and defective parts.

The viscosity of the resin as described above changes depending on the temperature of the molten resin, but this temperature must not be such as to damage the conductive paint portion or the support film portion as described above. Therefore, it is desirable that the temperature at the time of injection of the resin having the above viscosity range is 400° C. or lower.

In addition, the injection pressure of the above molten resin is 400 to 2300 kg.
/cd is better. If the injection pressure of resin in the above viscosity range exceeds 2300 kg/-, the pressure inside the mold will become too large and there is a risk of damaging the circuit.
This is because if it is lower than 0 Kg/aj, the circuit may not be transferred well.

In the present invention, examples of the resin used to form such a resin molded article include polyolefin resins such as polyethylene and polypropylene, as described above, but conventionally used materials for this type of resin molded article For example, 8BS, polyacetal,
It is clear that similar effects can be obtained using polysulfan, PP01-modified PPO, polycarbonate, old PS, and the like.

As mentioned above, the molded article 1 is taken out from the mold 8, the support film 6 is peeled off, and then it is immersed in water to which a shear tool condensation catalyst has been added. 6 and circuit pattern 7
(Because there is a risk that a crosslinking reaction may occur during the process, the support film 6 is preferably peeled off before being immersed in water).

By this immersion in water, the grafted organic silane coupling agents are mutually condensed and crosslinked. Therefore, at the interface between the circuit body 2 and the molded article 1, the circuit body 2 and the molded article 1 are bonded together by the crosslinking bond 4, and the bonding strength is improved. Furthermore, since a crosslinking reaction occurs in the resin forming the circuit body, the conductive particles contained in the resin are fixed. Therefore, the moisture-heat cycle and heat cycle of the manufactured conductive circuit are improved, and since the conductive particles are compressed and fixed, there is an advantage that the conductivity is improved.

Such silanol condensation catalysts include, for example, dibutyltin dilaurate, stannous acetate, stannous octylate,
Carboxylate salts such as lead naphthenate, zinc caprylate, iron 2-ethylhexanoate, cobalt naphthenate, organometallic compounds such as titanate esters and chelates such as tetrabutyl titanate, tetranonyl titanate and Included are bis(acetylaceryl)di-isopropyltitanate, organic bases such as ethylamine, hexylamine, dibutylamine, and pyridine, acids such as inorganic acids and fatty acids.

Such a silanol condensation catalyst is preferably 0.0
．． It is preferable to add at a rate of 01 to 1 mol/f, 0
．． If it is less than 01 mol/Il, there is a risk that the condensation reaction will not be sufficient, while if it exceeds 1 mol/Il, the material will be wasted.

Further, the immersion time is preferably 2 hours or more.

If the time is less than 2 hours, the crosslinking reaction may not occur sufficiently, while if it is more than 24 hours, it is not practical.

Example 1 A conductive paint (with the following composition) was applied on a polyester film.
A circuit pattern was printed using a viscosity of 70 poise), a line width of 0.8 mm, a distance between lines of 0.8 ms+, and a thickness of 25 μm.

Composition 1 Thermoplastic ABS resin 100 parts by weight Aromatic solvent 120 parts by weight Silver-coated copper particles 600 parts by weight (silane coupling agent) 2 parts by weight (organic peroxide)
0.1ii parts This circuit transfer foil is placed so that the support film is in contact with the inside of the injection mold for molding the resin molded product, and the polypropylene resin (
Injection conditions: injection temperature 220-240 t, injection pressure (gauge pressure > 800)
Kg/cd, back pressure 5Kg/ad, screw rotation speed 5O
r, p, n+,), the resin molded product was molded.

Next, after peeling off the support film, 0.0% of the (silanol condensation catalyst) was removed. The silane coupling agent was condensed and crosslinked by immersing it in water containing Of+ol/l for 5 hours.

In this way, the BS is applied onto the polypropylene resin molded product.
A good circuit with a resin line width of 0.8 av and a distance between lines of 0.81 was formed with high precision. The conductivity of this circuit is 0.1Ω
/ mouth or less, and the cellophane tape peeling resistance test was 100.
/100.

For comparison, when a circuit was formed under the same conditions using a circuit transfer foil manufactured using the conductive paint containing no silane coupling agent or organic peroxide (that is, no crosslinking reaction occurred), the conductivity was 0. .1Ω/mouth, and the sellotape peeling resistance test was O/100.

Furthermore, regarding the moist heat cycle and the heat cycle, in the case of the circuit with composition 1, no abnormal characters were generated, and in the case of the comparative example, lifting of the circuit part occurred after 5 cycles.

In the circuit obtained by transferring the circuit pattern at the same time as molding as in Example 1, the surface of the molded product and the surface of the circuit are on the same level (only the circuit part does not have a convex shape), so there is a problem in handling. There is also the advantage that circuit defects due to caution can be prevented.

〔Effect of the invention〕

As explained above, according to the conductive circuit according to the present invention, since the organic silane coupling agent and the organic peroxide are mixed into the conductive paint, they can be transferred to the resin molded product at the same time as the molded product. When a circuit is formed, the silane coupling agent causes a crosslinking reaction graft, and water and the condensation catalyst form a crosslink, resulting in the advantage that the adhesive strength between the resin molded product and the circuit body is significantly improved. Moreover, as a result, it becomes possible to use a polyolefin resin, which could not be used in the past, as a material for a resin molded article, which has the advantage that it becomes possible to easily manufacture circuits with low cost and solderability. Furthermore, since the conductive particles dispersed within the conductive circuit are fixed by the crosslinking reaction, the moisture-heat cycle and heat cycle are improved and durability is increased, and there is also the advantage that it is possible to improve the conductivity.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of one embodiment of the conductive circuit according to the present invention, FIG. 2 is a diagram schematically showing the vicinity of the interface between the conductive circuit main body and the resin molded product according to the present invention, and FIG. FIG. 4 is a cross-sectional view of the transfer foil for injection molding used in the invention, and is a schematic diagram of the injection mold used when manufacturing the conductive circuit of the invention. 1... Resin molded product, 2... Conductive circuit body, 3
... Graft branch, 4 ... Crosslinking bond, 6 ... Support film, 7 ... Circuit pattern, 8 ... Injection mold. Applicant's representative Masaki Amemiya Figure 2 - (a) H2 (b)

Claims (2)

[Claims] (1) A conductive circuit in which a conductive circuit body in which 300 to 1000 parts by weight of conductive particles are added to 100 parts by weight of resin is provided on a resin molded product by transfer, the conductive circuit body being RR' An organic compound represented by SiY_2 (in the above general formula, R is a monovalent olefinically unsaturated hydrocarbon group or a hydrocarbonoxy group, each Y is a hydrolyzable organic group, and R' is an R group or a Y group) Silane coupling agent 0.
5 to 50 parts by weight of a conductive circuit, and the interface between the conductive circuit body and the resin molded product is crosslinked with water and a condensation catalyst. (2) RR'SiY_2(
In the above general formula, R is a monovalent olefinically unsaturated hydrocarbon group or a hydrocarbonoxy group, each Y is a hydrolyzable organic group, and R' is an R group or a Y group. A circuit transfer printed with a circuit pattern that is easily removable from the support film immediately after heating and pressing, using a conductive paint containing 0.5 to 50 parts by weight of a ring agent and an organic peroxide for generating free radicals. The foil is placed on the inner wall of an injection mold for molding a resin molded product so that the support film is in contact with the inner wall, the molten resin is press-fitted into the mold to form a resin molded product, and the support film is After peeling off,
A method for producing a conductive circuit, which comprises immersing it in water containing a silanol condensation catalyst to cause a crosslinking reaction.