TWI732839B - Extensible conductive paste and manufacturing method of curved printed circuit board - Google Patents

Abstract

The present invention provides a ductile conductive paste, which can be spread out in order to obtain a curved printed circuit board by thermally deforming the thermoplastic substrate after printing and hardening. In a conductive paste containing a binder resin (A) composed of a thermoplastic resin, a conductive powder (B), and an organic solvent (C), the organic solvent (C) is a glycol ether solvent or/and Alcohol-based solvents are mixed to obtain a ductile conductive paste. The obtained paste is printed on a substrate made of a thermoplastic resin and then subjected to thermal deformation processing to obtain a curved printed circuit board.

Description

Extensible conductive paste and manufacturing method of curved printed circuit board

The present invention relates to three-dimensional circuit chips, curved printed circuit boards, and three-dimensional circuit parts used in switch parts of display panels, operation panels, portable phones, portable information devices, automobile interior parts, etc. for home appliances The ductile conductive paste used and its manufacturing method.

With the miniaturization and high performance of electrical equipment in recent years, the demand for three-dimensional three-dimensional structure of circuit chips, printed circuit boards, and three-dimensional molded products with electrical circuits formed on the surface has increased. Regarding the circuit chips and three-dimensional molded products with electrical circuits, it is known that a circuit pattern (electric circuit) is formed on an insulating base material made of synthetic resin by electrolytic plating and then processed into a three-dimensional shape by press molding or the like. In addition, as in Patent Document 1, it is known that a part of a three-dimensional molded product with a photoresist layer and a conductive layer is covered with a mask, and exposed, developed, and etched to provide a circuit pattern on the surface. For example, in Patent Document 2, the A method of injecting molten synthetic resin into the mold of a laminate formed by arranging circuit patterns and an adhesive laminated layer on a synthetic resin film to arrange circuit patterns on the surface of the three-dimensional molded product. [Prior Technical Documents] [Patent Documents]

[Patent Document 1] Japanese Patent Laid-Open No. 9-319068 [Patent Document 2] Japanese Patent Laid-Open No. 2001-36240

(Problem to be solved by the invention) However, the method of providing a circuit pattern on the surface of an insulating base material and molded article by plating treatment and etching treatment will produce harmful waste liquid during the steps of plating treatment and etching treatment. An undesirable situation where the environment causes adverse effects. In addition, the method of injecting synthetic resin into the mold of the laminated body on which the circuit pattern has been set has problems that the circuit pattern after molding cannot follow the deformation of the laminated body, the circuit pattern is cracked and peeled, and the conductivity is deteriorated.

The object of the present invention is to provide a ductile conductive paste, which can solve the above-mentioned conventional three-dimensional shape of the circuit chip, printed circuit board, and three-dimensional molded products have the problems, and even the circuit pattern laminated body uses heat. Deformation caused by pressure and the steps of forming will not cause circuit pattern cracking or peeling. (The way to solve the problem)

The inventors of the present case studied hard in order to achieve this objective, and found that the above-mentioned problems can be solved by the following means, which is an invention. The first invention of the present invention includes the following constitutions. [1] A ductile conductive paste characterized in that it contains a binder resin (A) composed of a thermoplastic resin, a conductive powder (B) and an organic solvent (C), and the organic solvent (C) is a glycol ether A solvent or/and an alcohol solvent. [2] The ductile conductive paste as in [1], wherein the boiling point of the organic solvent (C) is in the range of 100 to 300°C. [3] The ductile conductive paste according to [1] or [2], wherein the second solvent is a solvent containing a hydroxyl group which has a slower evaporation rate than the organic solvent (C). [4] The ductile conductive paste according to any one of [1] to [3], wherein the binder resin (A) is selected from polyester resins, polyurethane resins, and epoxy resins. , Phenoxy resin, vinyl chloride resin, cellulose derivative resin, polyvinyl acetal resin, acrylic resin and a mixture of one or more than two types. [5] The ductile conductive paste of any one of [1] to [4], wherein the glass transition temperature of the binder resin (A) is 30° C. or higher and the number average molecular weight is in the range of 3000 to 150,000. [6] A method for manufacturing a curved printed circuit board, which is characterized by comprising the following steps: printing the ductile conductive paste as described in any one of [1] to [5] on the plastic substrate and thermally deforming the plastic substrate .

The second invention of the present invention has the following configuration. [7] A ductile conductive paste containing a binder resin (A) composed of a thermoplastic resin, conductive powder (B), organic solvent (C) and carbon black powder (D), characterized by: F value: 75 to 95%. [8] The ductile conductive paste of [7], wherein the binder resin (A) is selected from polyester resins, polyurethane resins, epoxy resins, phenoxy resins, and vinyl chloride resins. One or a mixture of two or more of the group consisting of resin, cellulose derivative resin, polyvinyl acetal resin, and acrylic resin. [9] The ductile conductive paste of [7] or [8], wherein the glass transition temperature of the binder resin (A) is 20° C. or higher and the number average molecular weight is in the range of 3000-150000. [10] The ductile conductive paste according to any one of [7] to [9], wherein the organic solvent (C) is a glycol ether solvent or/and an alcohol solvent. [11] The ductile conductive paste according to any one of [7] to [10], wherein the boiling point of the organic solvent (C) is in the range of 100 to 300°C. [12] The ductile conductive paste according to any one of [7] to [11], wherein a solvent containing a hydroxyl group is used as the second solvent with an evaporation rate slower than that of the organic solvent (C). [13] A method for manufacturing a curved printed circuit board, which is characterized by including the following steps: printing a ductile conductive paste as in any one of [7] to [12] on a plastic substrate and thermally deforming the plastic substrate .

The third aspect of the present invention has the following configuration. [14] A ductile conductive paste containing a binder resin (A) composed of a thermoplastic resin, a conductive powder (B), an organic solvent (C) and a hardener (E), and is characterized by: the binder The resin (A) is selected from polyester resins, polyurethane resins, epoxy resins, phenoxy resins, vinyl chloride resins, cellulose derivative resins, polyvinyl acetal resins, and acrylic resins. One type or two or more types in the group, and the hardener (E) is either one or both of a blocked isocyanate or an epoxy compound. [15] The ductile conductive paste according to [14], wherein the organic solvent (C) is a glycol ether solvent or/and an alcohol solvent. [16] The ductile conductive paste of [14] or [15], wherein the boiling point of the organic solvent (C) is in the range of 100 to 300°C. [17] The ductile conductive paste according to any one of [14] to [16], wherein a solvent containing a hydroxyl group has an evaporation rate slower than that of the organic solvent (C) as the second solvent. [18] The ductile conductive paste according to any one of [14] to [17], wherein the hardener (E) is at least selected from the group consisting of diurea type, trimer type, and adduct type A blocked isocyanate. [19] The ductile conductive paste according to any one of [14] to [18], wherein the hardener (E) is a glycerin-type epoxy resin. [20] The ductile conductive paste according to any one of [14] to [19], wherein the glass transition temperature of the binder resin (A) is 30° C. or higher and the number average molecular weight is in the range of 3000-150000. [21] A method for manufacturing a curved printed circuit board, which is characterized by including the following steps: printing a ductile conductive paste as in any one of [14] to [20] on a plastic substrate and thermally deforming the plastic substrate .

The present invention preferably has the following constitutions. [22] The ductile conductive paste of [1] to [4], wherein the aforementioned binder resin (A) is a phenoxy resin. [23] A curved printed circuit board, characterized in that: on a non-developable substrate made of thermoplastic resin, a binder resin (A) made of phenoxy resin, conductive powder (B) ), and a hardening material composed of a conductive resin composition selected from the group consisting of diurea type blocked isocyanate, adduct type blocked isocyanate, and trimer type blocked isocyanate (D) conductive resin composition Wiring. [24] The curved printed circuit board of [23], wherein the non-developable substrate made of thermoplastic resin is polycarbonate resin or polyester resin.

The present invention preferably has the following constitutions. [25] The ductile conductive paste of [7] to [12], wherein the aforementioned binder resin (A) is a phenoxy resin. [26] A curved printed circuit board, characterized in that: on a non-developable substrate made of thermoplastic resin, a binder resin (A) made of a phenoxy resin, conductive powder (B) ), and the electrical wiring composed of the cured product of the conductive resin composition of carbon black powder (D). [27] The curved printed circuit board of [26], wherein the non-developable substrate made of thermoplastic resin is polycarbonate resin or polyester resin. [28] The curved printed circuit board of [26] or [27], wherein the cured material of the conductive resin composition contains a binder resin (A) composed of a phenoxy resin and a conductive powder (B) , And carbon black powder (D), one or more hardeners (E) selected from the group consisting of diurea type blocked isocyanate, adduct type blocked isocyanate, and trimer type blocked isocyanate (E) conductive resin composition Hardened object.

The present invention preferably has the following constitutions. [29] The ductile conductive paste of [14] to [20], wherein the aforementioned binder resin (A) is a phenoxy resin. [30] A curved printed circuit board, characterized in that: on a non-developable substrate made of thermoplastic resin, a binder resin (A) made of a phenoxy resin, conductive powder (B) ), and an electrical wiring consisting of a cured product of a conductive resin composition selected from the group consisting of diurea type blocked isocyanate, adduct type blocked isocyanate, and trimer type blocked isocyanate (E) . [31] The curved printed circuit board of [30], wherein the non-developable substrate made of thermoplastic resin is polycarbonate resin or polyester resin. (Effects of the invention)

The present invention relates to a ductile conductive paste, which is used after printing on a plastic substrate to thermally deform the plastic substrate to manufacture a curved printed circuit board. In particular, a thermally deformable plastic substrate is often used as a base material for curved printed circuit boards. There are many plastic materials with thermoplasticity and thermal deformation properties that have low resistance to organic solvents. Oftentimes, the conductive paste contains a binder resin, but at the same time, an organic solvent is used to liquefy and dissolve the binder resin. Therefore, if a conductive paste containing organic solvent is accidentally printed on a plastic substrate that can be thermally deformed, the solvent component of the conductive paste will contact the plastic substrate, which will cause unnecessary melting of the surface of the plastic substrate. The deformation of the substrate, or the occurrence of small cracks in the contact part, and the decrease of the mechanical strength of the substrate.

The conductive paste of the present invention does not have the aforementioned problems even if it is a plastic substrate that lacks solvent resistance, such as acrylic materials, polycarbonate materials, vinyl chloride materials, etc., and has excellent adhesion to the substrate. Even when the substrate is thermally deformed, the conductive layer formed with the conductive paste will still fully follow the deformation and still have excellent electrical properties after deformation.

Thermosetting resins are often used as binders for conductive pastes. The reason is that the hardening shrinkage accompanying thermal hardening promotes the direct contact of conductive particles with each other and forms a stronger hardened coating film, so it is easy to obtain advantages in terms of electrical characteristics. However, in the first invention of the present invention, even if a thermoplastic resin is used as a binder for thermal deformation in a subsequent step, it has unexpectedly been found that the same excellent electrical properties as the thermosetting resin can be obtained. It is believed that this is because the solvent component of the present invention exhibits the same effect on the curing process of the thermoplastic resin and the thermosetting resin during the drying and curing process.

In the second invention of the present invention, even if a thermoplastic resin is used as a binder for thermal deformation in a subsequent step, it has unexpectedly been found that the same excellent electrical properties as the thermosetting resin can be obtained. It is believed that this is because the carbon black added to the conductive paste in the present invention can not only reduce the influence of organic solvents on the substrate, but also play an effect as a filler in powder-reinforced plastics in the formation of a coating film. As a result, the ductile conductive paste of the present invention uses a thermoplastic resin as if it is a thermosetting resin, and a conductive coating film with excellent mechanical and electrical properties can be obtained after thermal deformation.

In the third aspect of the present invention, by using a specific curing agent to impart thermosetting properties to a thermoplastic resin as a binder, it is possible to obtain good electrical characteristics and reliability. Thermally deformed, the conductive layer will still fully follow the deformation and obtain a cured coating film with good ductility and excellent physical properties after deformation. It is believed that the reason is that in the combination of the hardener component and the resin component of the present invention, during the drying and hardening process, the binder resin reacts with the hardener to form a cross-linked structure. In the temperature range of the thermal deformation of the substrate, the cross-linked part It exhibits flexibility, maintains the cross-linked state and shows sufficient follow-up to deformation, and then regenerates a strong cross-linked body in the state of cooling after deformation.

Hereinafter, the ductile conductive paste according to the embodiment of the present invention will be described. In the present invention, a binder resin (A) composed of a thermoplastic resin, a conductive powder (B), an organic solvent (C), carbon black (D), and a curing agent (E) are used.

<Binder resin (A)> The binder resin (A) contained in the ductile conductive paste of the present invention needs to contain a resin with flexibility and three-dimensional formability as a main component. The type of binder resin (A) is not particularly limited as long as it is a thermoplastic resin. Examples include polyester resins, epoxy resins, phenoxy resins, polyamide resins, polyimide resins, and polycarbonates. Resin, polyurethane resin, phenol resin, polyvinyl acetal resin, acrylic resin, polystyrene, styrene-acrylic resin, styrene-butadiene copolymer, phenol resin, polyethylene resin, poly Carbonate resins, phenol resins, alkyd resins, styrene-acrylic resins, styrene-butadiene copolymer resins, polyether resins, polyether resins, vinyl chloride-vinyl acetate copolymer resins, ethylene-acetic acid Vinyl ester copolymers, polystyrene, silicone resins, fluorine resins, etc. These resins can be used alone or in the form of a mixture of two or more. Preferably, it is selected from the group consisting of polyester resin, polyurethane resin, epoxy resin, phenoxy resin, vinyl chloride resin, cellulose derivative resin, butyral resin, and acrylic resin. One type or a mixture of two or more types is preferable. In addition, among these resins, phenoxy resin and/or urethane resin and/or acrylic resin, and/or polyvinyl acetal resin are suitable as the binder resin (A).

In the present invention, one of the advantages of using phenoxy resin and/or urethane resin and/or acrylic resin, and/or polyvinyl acetal resin as the binder resin (A) can be cited: The binder resin has good solubility in a wide range of solvents such as ether solvents and alcohol solvents, and has good adhesion to various substrates. Ketone-based solvents and ester-based solvents, which are widely used as conductive pastes, sometimes cause damage to the substrate depending on the type of substrate, and therefore sometimes cause poor appearance and reduced ductility of printed circuits.

In the present invention, the phenoxy resin is a polyhydroxy polyether synthesized from bisphenols and epichlorohydrin, with a molecular weight of 3,000-150,000. The phenoxy resin used as the binder resin (A) in the present invention includes, for example, bisphenol A type, bisphenol A/F copolymerization type, bisphenol S type, and bisphenol A/S copolymerization type. Among them, the bisphenol A type is more preferable from the viewpoint of substrate adhesion.

In the present invention, the urethane resin is a polymer having a urethane bond and has a molecular weight of 3,000-150,000.

In the present invention, the acrylic resin is a resin obtained by radical polymerization reaction by adding a polymerization initiator to a radical polymerizable monomer such as acrylate or methacrylate, and heating, and has a molecular weight of 3,000-150,000.

In the present invention, the polyvinyl acetal resin is a resin obtained by acetalizing or butyralizing polyvinyl alcohol, and has a molecular weight of 3,000 to 150,000.

In the present invention, the number average molecular weight of the binder resin (A) is not particularly limited, and the number average molecular weight is preferably 3,000 to 150,000. It is more preferably in the range of 7,000 to 140,000, and still more preferably in the range of 10,000 to 130,000. If the number average molecular weight is too low, it is not ideal for the durability and heat resistance of the formed conductive film. On the other hand, if the number average molecular weight is too high, the cohesive force of the resin will increase, and the durability as a conductive film will increase, but the viscosity of the ductile conductive paste will increase, making it unsuitable for practical use.

In the present invention, in the first and third inventions, the glass transition temperature of the binder resin (A) is preferably 30°C or higher, more preferably 40°C or higher. If the glass transition temperature is low, the surface hardness of the silver coating film may decrease. In the second aspect of the present invention, the glass transition temperature of the binder resin (A) is preferably 15°C or higher, more preferably 20°C or higher. If the glass transition temperature is low, the surface hardness of the silver coating film may decrease.

<Conductive powder (B)> The conductive powder (B) used in the present invention includes noble metal powders such as silver powder, gold powder, platinum powder, and palladium powder, and base metal powders such as copper powder, nickel powder, aluminum powder, and brass powder. , Base metal powder obtained by plating or alloying precious metals such as silver. These metal powders may be used alone or in combination. Among them, if the conductivity, stability, cost, etc. are considered, it is better to use silver powder alone or silver powder as the main body. In addition, as the conductive powder (B), for example, non-metal powders such as carbon black powder can also be used.

The shape of the conductive powder (B) used in the present invention is not particularly limited. The shape of the metal powder known in the past, such as flakes (scaly), spherical, dendritic (dendrite), the spherical primary particles described in JP 9-306240 A aggregated into a three-dimensional shape Among them, spherical, agglomerated and flake-shaped metal powders are preferably used.

The center diameter (D50) of the conductive powder (B) used in the present invention is preferably 4 μm or less. By using the conductive powder (B) having a center diameter of 4 μm or less, the printed shape of the fine line tends to become better. When metal powder with a center diameter larger than 4μm is used, the shape of the thin lines after printing becomes worse. As a result, the thin lines may contact each other and cause a short circuit. The lower limit of the center diameter of the conductive powder (B) is not particularly limited. Considering the cost point of view, and if the particle size is changed, it is easy to agglomerate, resulting in difficulty in dispersion. The center diameter is preferably 80 nm or more. If the center diameter is smaller than 80nm, the cohesive force of the conductive powder increases, the printability and the storage stability of the ductile conductive paste deteriorate, and it is also undesirable from the viewpoint of cost.

In addition, the center diameter (D50) refers to the particle diameter (μm) at which the cumulative value becomes 50% in the cumulative distribution curve (volume) obtained by a certain measurement method. In the present invention, a laser diffraction scattering type particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., MICROTRAC HRA) is used to measure the cumulative distribution curve in the total reflection mode.

The content of the conductive powder (B) is preferably 400 parts by mass or more, and more preferably 560 parts by mass or more with respect to 100 parts by mass of the thermoplastic resin (A) in consideration of the good conductivity of the formed conductive film. In addition, the content of the component (B), considering the adhesion to the substrate, is a good point of view, and it is preferably 1,900 parts by mass or less, and more preferably 1,230 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin (A).

<Organic solvent (C)> The organic solvent (C) that can be used in the present invention is preferably a glycol ether solvent or/and an alcohol solvent. Glycol ether solvents and/or alcohol solvents hardly damage the resin film that can be three-dimensionally formed as a printing substrate, and the obtained conductive film exhibits good ductility. When solvents that do not contain these structures are used, the resin film that can be three-dimensionally formed may sometimes be damaged by the solvent, and the substrate of the obtained conductive film may become fragile, and sometimes it may not be able to obtain good ductility.

Glycol ether solvents include diethylene glycol dibutyl ether, diethylene glycol butyl methyl ether, triethylene glycol butyl methyl ether, diethylene glycol monobutyl ether, diethylene glycol monomethyl ether, and dipropylene glycol monomethyl ether. , Diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, ethylene glycol monophenyl ether, diethylene glycol isopropyl methyl ether, ethylene glycol monomethyl ether, diethylene glycol dimethyl ether, two Propylene glycol dimethyl ether, ethylene glycol dimethyl ether, propylene glycol dimethyl ether, propylene glycol monomethyl ether, polyethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tripropylene glycol dimethyl ether Ether, etc., but not limited to these. Among them, considering the excellent solubility of the blending component of the thermoplastic resin (A), the appropriate solvent volatility during continuous printing, and good printability by screen printing methods, dipropylene glycol monomethyl ether , Tripropylene glycol dimethyl ether and their mixed solvents are particularly preferred.

Alcohol-based solvents can include solvents with OH groups, such as butanol, cyclohexanol, methylcyclohexanol, heptanol, Texanol, butyl serosol, ethylene glycol, propylene glycol, butylene glycol, 3-methoxy Butyl-3-methyl-1-butanol, etc., but not limited to these. Among these, considering the excellent solubility of the blending component of the thermoplastic resin (A), the moderate volatility of the solvent during continuous printing, and the viewpoint that the suitability of printing by screen printing methods is good, 3-methoxy -3-methyl-1-butanol is particularly preferred.

In addition, an organic solvent other than the organic solvent (C) may be used in combination within a range that does not impair the effects of the present invention. Organic solvents that can be used in combination, such as ethyl diethylene glycol acetate (EDGAC), butanediol acetate (BMGAC), butanediol acetate (BDGAC), cyclohexanone, toluene, isophorone, Gamma-butyrolactone, benzyl alcohol, Solvesso 100, 150, 200 manufactured by Exxon Chemicals, propylene glycol monomethyl ether acetate, adipic acid, succinic acid and a mixture of dimethyl glutarate (for example: DuPont (stock) Company's DBE), terpineol, etc., but not limited to these.

The boiling point of the organic solvent (C) that can be used in the present invention is not particularly limited. Considering the viewpoint of keeping the volatilization rate of the organic solvent in an appropriate range, the boiling point is preferably 100°C or higher but not 300°C, and more preferably the boiling point is 150°C or higher. Up to 280°C. The conductive paste of the present invention is generally prepared by dispersing the thermoplastic resin (A), the conductive powder (B), the organic solvent (C) and other components as required by a three-roll mill or the like. In this case, the organic solvent If the boiling point is too low, the solvent will volatilize during the dispersion and cause a concern that the composition ratio of the conductive paste will change. On the other hand, if the boiling point of the organic solvent is too high, depending on the drying conditions, there may be a large amount of solvent remaining in the coating film, which may cause deterioration of the conductivity of the coating film and lower reliability.

The content of the organic solvent (C) is preferably 5 parts by weight or more and 40 parts by weight or less with respect to 100 parts by weight of the total weight of the paste, and more preferably 10 parts by weight or more and 35 parts by weight or less. If the content of the organic solvent (C) is too high, the viscosity of the paste will become too low, and it will tend to sag when printing fine lines. On the other hand, if the content of the organic solvent (C) is too low, the viscosity of the paste will become extremely high, and when a conductive film is formed, for example, the screen printability may be significantly reduced.

The ductile conductive paste of the present invention preferably contains a solvent that has a slower evaporation rate than the first solvent and contains a hydroxyl group as the second solvent. The solvent containing the hydroxyl group acts as a reducing agent, so it can reduce the resistance value of the circuit obtained by the ductile conductive paste. This second solvent is chosen to have a slower evaporation rate than the first solvent. In the drying step after printing the ductile conductive paste, the second solvent stays in the coating film for a long period of time and is easy to exert its effect as a reducing agent.

The following inorganic substances can be added to the ductile conductive paste of the present invention. Inorganic substances include silicon carbide, boron carbide, titanium carbide, zirconium carbide, hafnium carbide, vanadium carbide, tantalum carbide, niobium carbide, tungsten carbide, chromium carbide, molybdenum carbide, calcium carbide, diamond-like carbon and other carbides; boron nitride , Titanium nitride, zirconium nitride and other nitrides, zirconium boride and other borides; titanium oxide (titanium oxide), calcium oxide, magnesium oxide, zinc oxide, copper oxide, aluminum oxide, silicon dioxide, colloidal dioxide Various oxides such as silicon; various titanium oxide compounds such as calcium titanate, magnesium titanate, and strontium titanate; sulfides such as molybdenum disulfide; various fluorides such as magnesium fluoride and carbon fluoride; aluminum stearate and stearic acid Calcium, zinc stearate, magnesium stearate and other metal soaps; others, talc, bentonite, calcium carbonate, kaolin, glass fiber, mica, etc. can be used. By adding these inorganic substances, printability, heat resistance, mechanical properties, and long-term durability are improved. Among them, in the malleable conductive paste of the present invention, considering durability and printing suitability, especially from the viewpoint of imparting suitability to screen printing, silicon dioxide is preferred.

In addition, the ductile conductive paste of the present invention may be blended with a thixotropy imparting agent, defoaming agent, flame retardant, adhesion imparting agent, anti-hydrolysis agent, leveling agent, plasticizer, antioxidant, and ultraviolet light. Absorbents, flame retardants, pigments, dyes. Furthermore, carbodiimide, epoxide, etc., which are resin decomposition inhibitors, can also be appropriately blended. These can be used alone or in combination.

<Carbon black powder (D)> In the present invention, it is preferable to add not only the conductive powder (B) but also the carbon black powder (D) in the second invention. The addition of carbon black powder can increase the strength and toughness of the coating film, and increase the ductility of the coating film in a high temperature environment. In addition, the addition of carbon black has the effect of reducing the damage of the organic solvent contained in the conductive paste to the material to be printed. In the present invention, carbon black is a general term for carbon-based fine particles. In the present invention, the carbon-based particles can use graphite powder, activated carbon powder, flake graphite powder, acetylene black, Ketjen black, fullerene, single-layer carbon nanotubes, multi-layer carbon nanotubes, and carbon nanotubes. Cone and so on. The carbon-based particles suitable for use in the present invention are graphite powder, flake graphite powder, activated carbon powder, and Ketjen black. In the present invention, it is preferable to use carbon-based particles having at least a BET specific surface area of 1000 m ^{2 /g or more.}

The amount of carbon black powder added is preferably in the range of 0.3 to 3.5% by weight relative to the total amount of conductive powder (B). The range of 0.5 to 3.0% by weight is more desirable, and the range of 0.7 to 2.5% by weight is most desirable. If the addition amount is less than 0.3% by weight, the effect of increasing the strength and toughness of the coating film can hardly be exhibited, and it will become a coating film with poor ductility. In addition, if the addition amount exceeds 3.5% by weight, good electrical conductivity may not be obtained in some cases.

In the first invention and the second invention of the present invention, the ductile conductive paste of the present invention may be blended with a hardener that reacts with the binder resin (A) to the extent that the effect of the present invention is not impaired. By blending the hardener, the hardening temperature is increased, and the load of the production step may increase, but it can be expected that the crosslinking caused by the heat generated when the coating film is dried will improve the moisture and heat resistance of the coating film. Furthermore, in the third aspect of the present invention, a curing agent is used in order to impart thermosetting properties to the binder resin.

<Hardening agent (E)> The kind of hardening agent (E) that can be used in the present invention is not limited, but considering adhesion, bending resistance, hardening properties, etc., isocyanate compounds and epoxy compounds are particularly preferred. Furthermore, if these isocyanate compounds are those with blocked isocyanate groups, the storage stability is improved, which is more desirable. Examples of curing agents other than isocyanate compounds and epoxy compounds include amino resins such as methylated melamine, butylated melamine, benzoguanamine, and urea resin, and well-known compounds such as acid anhydrides, imidazoles, epoxy resins, and phenol resins. Among these hardeners, known catalysts or accelerators selected according to their types can be used in combination. The blending amount of the hardener is preferably 0.5-50 parts by mass relative to 100 parts by mass of the binder resin (A), preferably 1-30 parts by mass, and even more preferably 2-20 parts by mass.

The isocyanate compound that can be blended in the ductile conductive paste of the present invention, such as aromatic or aliphatic diisocyanate, trivalent or higher polyisocyanate, etc., can be either a low molecular compound or a high molecular compound. For example: aliphatic diisocyanates such as tetramethylene diisocyanate and hexamethylene diisocyanate, aromatic diisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, xylene diisocyanate, hydrogenated diphenylmethane diisocyanate , Hydrogenated xylene diisocyanate, dimer acid diisocyanate, isophorone diisocyanate and other alicyclic diisocyanates, or trimers of these isocyanate compounds, and excess of these isocyanate compounds with, for example, ethylene glycol, Propylene glycol, trimethylolpropane, glycerin, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine and other low molecular active hydrogen compounds or various polyester polyols, polyether polyols, polyamides A terminal isocyanate group-containing compound obtained by the reaction of a polymer active hydrogen compound, etc. In addition, blocking agents for isocyanate groups include phenols such as phenol, thiophenol, methylthiophenol, ethylthiophenol, cresol, xylenol, resorcinol, nitrophenol, and chlorophenol; acetone oxime , Methyl ethyl ketoxime, cyclohexanone oxime and other oximes; methanol, ethanol, propanol, butanol and other alcohols; ethylene chlorohydrin (ethylene chlorohydrin), 1,3-dichloro-2-propanol, etc. Halogen substituted alcohols; tertiary alcohols such as tertiary butanol and tertiary amyl alcohol; ε-caprolactam, δ-valerolactam, γ-butyrolactam, β-propiolactam and other internal alcohols Amines, in addition to aromatic amines, imines, acetone, acetone acetate, ethyl malonate and other active methylene compounds, mercaptans, imines, imidazoles , Urea, diaryl compounds, sodium bisulfite, etc. Among them, considering hardening properties, oximes, imidazoles, and amines are particularly preferred.

In the present invention, it is preferable to use at least one blocked isocyanate selected from the group consisting of diurea type, trimer type, and adduct type as the hardener (E). Especially when the diurea type is used, it is possible to obtain an excellent cured coating film that takes into account the physical properties and ductility of the cured product.

Diurea-type blocked isocyanates include model 7960, model 7961 (all manufactured by Baxenden), which are obtained by blocking aliphatic isocyanate with dimethylpyrazole, and use dimethylpyrazole and diethyl malonate. Model 7991 (manufactured by Baxenden) obtained by capping the ester, capped type of DURANATE 24A-100, capped type of DURANATE 22A-75P, capped type of DURANATE 21S-75E (all are Asahi Kasei Co., Ltd.) Company system) and so on.

The trimer-type blocked isocyanate can include the water-based model AquaBI200, the model AquaBI220 (all made by Baxenden), and the aliphatic isocyanate is blocked with dimethylpyrazole, the model 7951 and the model 7982 (all are Baxenden) (Manufactured by Baxenden), model 7990, model 7992 (all manufactured by Baxenden), etc., which are end-capped with dimethylpyrazole and diethyl malonate.

Adduct-type blocked isocyanates include DURANATE 　 P301-75E blocked type, DURANATE 　 E402-80B blocked type, DURANATE E405-70B blocked type, DURANATE 　 AE700-100 blocked type (all are manufactured by Asahi Kasei Co., Ltd.) Wait.

Epoxy compounds that can be blended in the ductile conductive paste of the present invention, such as aromatic or aliphatic diglycidyl ether, trivalent or higher polyglycidyl ether, etc., can be low-molecular compounds, high-molecular compounds Any of them. For example: glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, neopentylerythritol polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polycyclic Propylene oxide, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, hydrogenated bisphenol type diglycidyl ether, ethylene glycol diglycidyl ether, diethylene glycol Diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, etc.

When an epoxy compound is used as the curing agent (E) in the present invention, it is preferable to use an aliphatic epoxy compound in consideration of ductility. A particularly desirable epoxy compound is a glycerin type epoxy resin.

<<Physical properties required for the ductile conductive paste of the present invention>> The viscosity of the ductile conductive paste of the present invention is not particularly limited, and can be appropriately adjusted according to the method of forming the coating film. For example, when the ductile conductive paste is applied to the substrate by screen printing, the viscosity of the ductile conductive paste at the printing temperature is preferably 100 dPa·s or more, more preferably 150 dPa·s or more. The upper limit is not particularly limited, but if the viscosity is too high, the screen printability may decrease.

For the ductile conductive paste of the present invention, the F value is preferably 60-95%, more preferably 75-95%. The value of the mass parts of the filler contained in the F-value system paste relative to 100 parts by mass of the total solid content is expressed by F-value=(parts by mass of the filler/parts by mass of the solid content)×100. The mass part of the filler referred to here is the mass part of the conductive powder, and the mass part of the solid content is the mass part of the components other than the solvent, including all of the conductive powder, binder resin, other hardeners, and additives. If the F value is too low, a conductive film with good conductivity cannot be obtained. If the F value is too high, the adhesion between the conductive film and the substrate and/or the surface hardness of the conductive film will tend to decrease, and printing cannot be avoided. Sexual decrease. Also, here, conductive powder refers to both metal powder and non-metallic conductive powder.

<<The manufacturing method of the ductile conductive paste of the present invention>> The ductile conductive paste of the present invention can be prepared by mixing thermoplastic resin (A), conductive powder (B), organic solvent (C) and optionally The other ingredients are produced by dispersing with a three-roller, etc. An example of a more ideal production procedure is disclosed here. First, the thermoplastic resin (A) is dissolved in the organic solvent (C). After that, the conductive powder (B) and the additives as necessary are added, and the dispersion is carried out using a double planetary mixer, a dissolver, a planetary mixer, etc. After that, it was dispersed with a three-roll mill to obtain a conductive paste. The conductive paste obtained in this way can be filtered as needed. Use other dispersing machines, such as bead mills, kneaders, extruders, etc., to disperse without any problems.

＜＜The conductive film of the present invention, the conductive laminate and their manufacturing method＞＞ In the present invention, the ductile conductive paste can be formed into a resin film that can be three-dimensionally formed by a simple method such as a printing method. For the coating film of the circuit pattern, the organic solvent (C) contained in the coating film is volatilized and the coating film is dried to form the conductive film of the present invention. The resin film that can be three-dimensionally formed may be a flat sheet that can be three-dimensionally formed before being formed into a three-dimensional shape. The resin film may be a translucent resin film such as a colorless and transparent film, a colored translucent film, or an opaque resin film. As the resin film, various resin films with excellent flexibility can be used, such as polyester-based, polycarbonate-based, polyethylene-based, polypropylene-based, polyamide-based, and thermoplastic elastomeric resin films. Among them, considering that transparency and moldability are both good, it is preferable to use a polycarbonate film or a polycarbonate/polybutylene terephthalate mixed film, or a polyethylene terephthalate film. The thickness of the film or sheet is not particularly limited, and it can be about 20 to 9000 μm, preferably 50 to 500 μm. If the film thickness is thinner than the predetermined range, the film may be curled when the circuit pattern is printed, and the film may be damaged during forming. In addition, if the thickness of the film or sheet exceeds a predetermined range, the formability of the film may decrease.

The method of coating or printing the malleable conductive paste of the present invention on a substrate to form a coating film, and applying or printing the malleable conductive paste on the substrate is not particularly limited, but if the screen printing method is used For printing, it is ideal to consider the simplicity of the steps and the viewpoint that it is a popular technology in the industry where the ductile conductive paste is used to form electrical circuits.

Three-dimensional forming processing methods include, for example, vacuum forming processing, press forming processing, hydroforming processing, etc., but are not limited to these.

The resin film substrate coated with the ductile conductive paste of the present invention and capable of three-dimensional forming processing is preferably a material that has excellent dimensional stability, is easily deformed at high temperature, and can be formed three-dimensionally. For example, a film made of materials with excellent flexibility such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, or polycarbonate. The thickness of the substrate is not particularly limited, and 50-500 μm is preferred. For the mechanical properties, shape stability, and handling properties of the pattern forming material, 100-250μm is more ideal.

In addition, by performing physical treatment and/or chemical treatment on the surface of the substrate coated with the ductile conductive paste of the present invention, the adhesion between the conductive film and the substrate can be improved. Physical treatment methods, such as sandblasting, wet sandblasting to spray liquid containing particles, corona discharge treatment, plasma treatment, ultraviolet or vacuum ultraviolet irradiation treatment, etc. In addition, the chemical treatment method includes, for example, a strong acid treatment method, a strong alkali treatment method, an oxidizing agent treatment method, and a coupling agent treatment method.

The step of volatilizing the organic solvent (C) is preferably carried out at room temperature and/or under heating. When heating, considering the conductivity, adhesion, and surface hardness of the conductive film after drying, the heating temperature is preferably 80°C or higher, preferably 100°C or higher, and 110°C or higher. In addition, considering the heat resistance of the transparent conductive layer of the substrate and the viewpoint of energy saving in the production process, the heating temperature is preferably 150°C or less, preferably 135°C or less, and 130°C or less. When a curing agent is blended in the conductive paste of the present invention, if the step of volatilizing the organic solvent (C) is performed under heating, the curing reaction proceeds.

The thickness of the conductive film of the present invention can be set to an appropriate thickness according to the intended use. However, considering that the conductivity of the conductive film after drying is good, the thickness of the conductive film is preferably 3 μm or more and 100 μm or less, and more preferably 4 μm or more and 80 μm or less. If the thickness of the conductive film is too thin, it may not be able to achieve the desired conductivity as a circuit. If the film thickness is too thick, long-term high-temperature heating is required to volatilize the solvent, which may sometimes cause damage to the resin film that can be used as a printing substrate for three-dimensional forming. [Example]

Examples and comparative examples are given below to describe the present invention in more detail. In addition, the present invention is not limited to the following embodiments. Also, unless otherwise specified, the "parts" in the example means "parts by weight".

In the present invention, the evaluation of the conductive paste is carried out according to the following method. 1. The conductive laminate test piece is made on a polycarbonate (PC) film with a thickness of 400μm (FE-2000 manufactured by Mitsubishi Gas Chemical Co., Ltd.) or a polyester (PET) film with a thickness of 100μm (Toray Co., Ltd. ) Lumirror S100), a 150-mesh polyester screen was used to print the conductive paste by the screen printing method, and dried in a hot-air circulating drying oven at 130°C for 30 minutes to form a coating film. In addition, the coating thickness at the time of printing is adjusted so that the dry film thickness becomes 10 to 30 μm. After that, a conductive laminate test piece with a width of 1mm and a length of 100mm with a width of 5mm and a length of 5mm on both sides for the measurement of specific resistance as shown below, and a width of 15mm and length of 110mm for the measurement of adhesion are produced. The conductive laminate test piece.

2. Specific resistance Measure the circuit resistance and film thickness of a conductive laminate test piece made on a PC film or PET film, and calculate the specific resistance. The thickness of the film was measured using Gauge Stand ST-022 (manufactured by Ono Sokki Co., Ltd.) with the thickness of the film as the zero point, and the thickness of the cured coating film at two points on the left and right terminal portions was measured, and the average value was used. The circuit resistance was measured on 3 test pieces using the RM3544 resistance value tester manufactured by HIOKI, and the average value was used.

3. Adhesion is used in 1 conductive laminate test piece made on PC film or PET film, using Cellotape (registered trademark) (manufactured by Nichiban Co., Ltd.) in accordance with JIS 　 K-5400-5-6: 1990, Evaluate by peeling test. However, the number of cuts in each direction of the grid pattern is set to 11, and the cutting interval is set to 1mm. 100/100 means no peeling and good adhesion, 0/100 means all peeling.

4. Chemical attack 1. Whether the conductive laminate test piece made on PC film or PET film has chemical attack on the PC substrate is evaluated according to the following method. Use an optical microscope (VHX-1000 manufactured by Keyence) to observe at 100 times, and judge whether there are traces of the coating film's hardening and shrinkage around the coating film. When there are traces around the coating film, it is rated as ×, and when the trace cannot be confirmed, it is rated as ○.

5. Evaporation rate The evaporation rate of the solvent used in the examples and comparative examples at 130°C was measured using a differential thermal and thermogravimetric simultaneous measurement device (TG-DTA: Shimadzu TA-60, DTG-60) under the following conditions , And measure the weight change (TG) from 2 min from the start of the measurement to the end of the test, find the average (N=3), and define it as the evaporation rate at 130 degrees. <TG-DTA measurement conditions> Sample size: 40mg Initial temperature: 30°C. Measurement conditions "Heating rate" 40°C/min" Holding temperature "130°C" Holding time" 30min The evaporation rate of the solvent used is shown in Table 1.

6. Ductility Evaluation of ductility is based on the following measurement methods. A conductive laminate test piece with a width of 5mm and a length of 5mm on both sides of a conductive laminate with a terminal part of 5mm in length and a length of 100mm, which was produced for the purpose of measuring specific resistance, was used as a measurement sample, and an autograph made by Shimadzu was used. AG-X　plus clamps both ends of the measurement sample. At this time, the distance between the two chucks was set to 12 cm, and the chucks were made to be outside the terminal portion of the measurement sample. In addition, in a gas environment of 140°C, the conductive laminate test piece is stretched along the longitudinal direction of the measurement sample at a speed of 25mm/min until the distance between the chucks becomes 10%, 20%, 40%, and 80% To the length. (The initial chuck interval is set to 100, and the state extended to 110 is set to elongation of 10%.) After that, an optical microscope (VHX-1000 manufactured by Keyence) is used to observe at 100 times to confirm whether the coating film is cracked or peeled. Those with no cracking or peeling of the coating film were rated as ○, and those with cracking and peeling were rated as ×. In addition, when the rate of change of circuit resistance was measured, the rate of change of 300% or less was rated as ○, the rate of more than 300% and 1,000% or less was rated as △, and the rate of more than 1,000% was rated as ×. 7. Humidity and heat resistance test: After standing for 120 hours at 85°C and 85%RH (relative humidity), the conductive laminate test piece made on PC film and PET film for evaluating the specific resistance and adhesion take out. Various evaluations were carried out after leaving it at room temperature for 24 hours.

<Example 1> As the resin binder (A), 500 parts of the phenoxy resin PKHC manufactured by InChem Corporation (dipropylene glycol monomethyl ether (400 parts) as the organic solvent (C)) was used as the conductive powder (B) ) 1000 parts of flake silver powder (D50=3.5μm), 10 parts of carbon, 10 parts of propylene glycol as the second solvent, and 30 parts of ethyl diethylene glycol acetate as other organic solvents. The three-roller kneader is used to disperse twice. After that, the obtained conductive paste was printed with predetermined patterns on the PET substrate and the PC substrate, respectively, and dried with a hot air dryer at 130° C.×30 minutes to obtain a conductive film. After that, using this conductive film, basic physical properties such as specific resistance and adhesion were measured and evaluated. The evaluation results of paste and paste coating film, conductivity, chemical attack, and ductility are shown in Table 2-1 and Table 2-2.

<Examples 2-10> The resin and the mixing ratio of the conductive paste were changed, and Examples 2-13 were implemented. The compounding ratio and evaluation results of the conductive paste are shown in Table 2-1 and Table 2-2. In the examples, good physical properties of the coating film and no chemical attack were evaluated. In addition, it was confirmed that for the binder resin (A)-1, when the organic solvent (E) was added, the conductivity was improved compared to the unadded product.

In addition, in Table 2-1 and Table 2-2, binder resin, conductive powder, organic solvent, carbon, and other blends are listed below. Binder resin A (1): Phenoxy resin PKHC manufactured by InChem Corporation (weight average molecular weight: 43,000 glass transition temperature: 67°C) Binder resin A (2): Phenoxy resin PKHH" manufactured by InChme Corporation (weight average molecular weight: 57,000 glass transition temperature: 70°C), adhesive resin A (3): acrylic resin Olicox KC-7000 manufactured by Kyoeisha Chemical Co., Ltd. (weight average molecular weight: 30.000 glass transition temperature: 56°C) adhesive resin A (4): poly Ester resin (obtained by the patent applicant in this case) 　Vylon GK890 (weight average molecular weight: 17.000 glass transition temperature: 20°C) Binder resin A (5): polyvinyl acetal resin Sekisui Chemical Co., Ltd. BM-5 (weight average molecular weight) : 53,000 Glass transition temperature: 67°C) Binder resin A(6): Polyurethane resin Desmocoll 500 manufactured by Sumitomo Bayer (weight average molecular weight: 97,000 Glass transition temperature: 47°C) Conductive powder B(1): Flake silver powder (D50: 3.5μm) Conductive powder B(2): Spherical silver powder (D50: 1.4μm) Organic solvent C(1): Dipropylene glycol monomethyl ether (Haisorubu DPM) manufactured by Toho Chemical Co., Ltd. Organic Solvent C(2): 3-methoxy-3-methyl-1-butanol (Solfit) manufactured by Kuraray Co., Ltd. Second organic solvent (1): Propylene glycol (industrial propylene glycol) manufactured by Adeka Co., Ltd. 2 Organic solvents (2): 1,3 butanediol (1,3 butanediol) manufactured by Sankyo Chemical Co., Ltd. Other organic solvents (1): Ethylene glycol acetate (EDGAC) manufactured by Daicel (Stock) Other organic solvents (2): Diacetone alcohol manufactured by Sankyo Chemical Co., Ltd. Other organic solvents (3): Dibasic acid ester (DBE) manufactured by Invista Corporation Carbon black powder: Ketjen Black manufactured by LION Corporation (ECP-600JP) ) Hardener: Diurea-type blocked isocyanate manufactured by Baxenden (Model 7960) Hardening catalyst: KS1260 manufactured by Kyodo Pharmaceutical Co., Ltd. Dispersant: Disperbyk193 manufactured by BYK Additive: BYK-410 manufactured by BYK

<Comparative Example 1> The organic solvent used 100% EDGAC, except that the silver paste was produced in the same manner as in Example 1, and the obtained conductive pastes were printed on the PC substrate in a predetermined pattern, and then set at 130°C × It was dried in a hot air dryer for 30 minutes to obtain a conductive film. After that, basic physical properties such as specific resistance and adhesion were measured and evaluated. The evaluation results of the paste and the paste coating film are shown in Table 2-1 and Table 2-2.

<Comparative Example 2> In accordance with the components and ratios shown in Table 2-1 and Table 2-2, a silver paste was prepared in the same manner as in Comparative Example 1, and a coating film was prepared using a PC film as a base material. The same as Comparative Example 1 The physical properties of the coating film were measured and evaluated. The evaluation results are shown in Table 2-1 and Table 2-2.

From Examples 1 to 10 and Comparative Examples 1 to 2, it can be seen that the ductile conductive paste of the present invention has good ductility, good adhesion to the substrate, and excellent conductivity.

<Application Example 1> On a polycarbonate (PC) film (FE-2000 manufactured by Mitsubishi Gas Chemical Co., Ltd.) with a thickness of 400 μm, the ductile conductive paste obtained in Example 1 was used to print a predetermined circuit pattern to dryness The film thickness is 15μm±3μm, and it is dried under predetermined conditions. Secondly, the obtained polycarbonate film with circuit pattern is curved using a male/female mold with a diameter of 30mm in a hemispherical shape. The obtained circuit pattern has no disconnection and no conduction failure. Hereinafter, the ductile conductive pastes obtained in Examples 2 to 10 were used in the same manner, and the curved surface workability was evaluated in the same manner. As a result, none of the ductile pastes had cracks or poor conduction, and had practically satisfactory electrical properties for a three-dimensional curved printed circuit board. <Application Example 2> The polycarbonate (PC) film in Application Example 1 was replaced with a 188μm thick easy-to-form polyester film "SOFTSHINE" (manufactured by Toyobo Co., Ltd.), and the following operations were performed in the same way to obtain a three-dimensional shape The curved printed circuit board. The obtained circuit pattern has no disconnection and no conduction failure. Hereinafter, the ductile conductive pastes obtained in Examples 2 to 10 were used in the same manner, and the curved surface workability was evaluated in the same manner. As a result, none of the ductile pastes had cracks or poor conduction, and had practically satisfactory electrical properties for a three-dimensional curved printed circuit board. <Application Example 3> Replace the polycarbonate (PC) film in Application Example 1 with a polyethylene naphthalate "Tenonex" (manufactured by Teijin DuPont Co., Ltd.) with a thickness of 125 μm, and the following operations are the same , Obtain a three-dimensional curved printed circuit board. The obtained circuit pattern has no disconnection and no conduction failure. Hereinafter, the ductile conductive pastes obtained in Examples 2 to 10 were used in the same manner, and the curved surface workability was evaluated in the same manner. As a result, none of the ductile pastes had cracks or poor conduction, and had practically satisfactory electrical properties for a three-dimensional curved printed circuit board.

<Example 11> As the resin binder (A), 500 parts of phenoxy resin PKHC manufactured by InChem Corporation (contains dipropylene glycol monomethyl ether (400 parts) for the organic solvent (C)) as a conductive powder (B) 1000 parts of flake silver powder (D50=3.5μm), 10 parts of carbon black, 10 parts of propylene glycol as the second solvent, and 30 parts of ethylene glycol acetate as other organic solvents were blended, and passed The cooled three-roller kneader performs the dispersion twice. Then, the obtained conductive paste was printed on the PET substrate and the PC substrate with predetermined patterns, and then dried with a hot air dryer at 130° C.×30 minutes to obtain a conductive film. After that, using this conductive film, basic physical properties such as specific resistance and adhesion were measured and evaluated. The evaluation results of paste and paste coating, conductivity, chemical attack, and ductility are shown in Table 3-1 and Table 3-2.

<Examples 12-18> The resin and the mixing ratio of the conductive paste were changed, and Examples 12-18 were implemented. The compounding ratio and evaluation results of the conductive paste are shown in Table 3-1 and Table 3-2. In the examples, good physical properties of the coating film and no chemical attack were evaluated. In addition, in Table 3-1 and Table 3-2, binder resin, conductive powder, organic solvent, carbon, and other blends are listed below. Binder resin A (1): Phenoxy resin PKHC manufactured by InChem Corporation (weight average molecular weight: 43,000 glass transition temperature: 67°C) Binder resin A (2): Phenoxy resin PKHH" manufactured by InChme Corporation (weight average molecular weight: 57,000 glass transition temperature: 70°C), adhesive resin A (3): acrylic resin Olicox KC-7000 manufactured by Kyoeisha Chemical Co., Ltd. (weight average molecular weight: 30.000 glass transition temperature: 56°C) adhesive resin A (4): polyester Resin (manufactured by Toyobo Co., Ltd.) 　Vylon GK890 (weight average molecular weight: 17.000 glass transition temperature: 20°C) Binder resin A (5): polyvinyl acetal resin manufactured by Sekisui Chemical Co., Ltd. BM-5 (weight average molecular weight: 53,000 Glass transition temperature: 67°C) Binder resin A(6): Polyurethane resin Desmocoll 500 manufactured by Sumitomo Bayer Co., Ltd. (weight average molecular weight: 97,000 Glass transition temperature: 47°C) Conductive powder B(1): Chips Flake silver powder (D50: 3.5μm) Conductive powder B(2): Spherical silver powder (D50: 1.4μm) Organic solvent C(1): Dipropylene glycol monomethyl ether (Haisorubu DPM) manufactured by Toho Chemical Co., Ltd. Organic solvent C (2): 3-methoxy-3-methyl-1-butanol (Solfit) manufactured by Kuraray Co., Ltd. Organic solvent C (3): 1,3-Butanediol manufactured by Sankyo Chemical Co., Ltd. (1 ,3 Butanediol) Other organic solvents (1): Daicel (stock) ethylene glycol acetate (EDGAC) Other organic solvents (2): Sankyo Chemical (stock) diacetone alcohol and other organic solvents (3): Dibasic acid ester (DBE) manufactured by Invista Corporation Carbon black powder: Ketjen Black (ECP-600JP) manufactured by Lion Corporation Hardener: Diurea type blocked isocyanate manufactured by Baxenden Corporation (Model 7960) Hardening catalyst: Common KS1260 manufactured by Pharmaceutical Co., Ltd. Dispersant: Disperbyk193 manufactured by BYK Additive: BYK-410 manufactured by BYK

<Comparative Example 11> No carbon black powder was used, except that the paste composition was the same as in Example 1. A silver paste was prepared, and the obtained conductive paste was printed on the PC substrate with a predetermined pattern, and then heated at 130°C ×30 minutes were dried with a hot air dryer to obtain a conductive film. After that, basic physical properties such as specific resistance and adhesion were measured and evaluated. The evaluation results of the paste and the paste coating film are shown in Table 3-1 and Table 3-2.

<Comparative Examples 12-14> In accordance with the components and proportions shown in Table 3-1 and Table 3-2, a silver paste was prepared in the same manner as in Comparative Example 1, and a coating film was prepared using a PC film as a substrate, and compared with In Example 11, the physical properties of the coating film were measured and evaluated in the same manner. The evaluation results are shown in Table 3-1 and Table 3-2.

From Examples 11-18 and Comparative Examples 11-14, it can be seen that the ductile conductive paste of the present invention has good ductility, good adhesion to the substrate, and excellent conductivity.

<Application Example 11> On a polycarbonate (PC) film (FE-2000 manufactured by Mitsubishi Gas Chemical Co., Ltd.) with a thickness of 400 μm, a predetermined circuit pattern was printed using the ductile conductive paste obtained in Example 1 to make The dry film thickness becomes 15μm±3μm, and it is dried under predetermined conditions. Secondly, the obtained polycarbonate film with circuit pattern is curved using a male/female mold with a diameter of 30mm in a hemispherical shape. The obtained circuit pattern has no disconnection and no conduction failure. Hereinafter, the ductile conductive pastes obtained in Examples 12 to 18 were used in the same manner, and the curved surface workability was evaluated in the same manner. As a result, none of the ductile pastes had cracks or poor conduction, and had practically satisfactory electrical properties for a three-dimensional curved printed circuit board.

<Application Example 12> The polycarbonate (PC) film in Application Example 11 was replaced with an easy-formable polyester film "SOFTSHINE" (manufactured by Toyobo Co., Ltd.) with a thickness of 188 μm. The following operations were performed in the same way to obtain a three-dimensional Shaped curved printed circuit board. The obtained circuit pattern has no disconnection and no conduction failure. Hereinafter, the ductile conductive pastes obtained in Examples 12 to 18 were used in the same manner, and the curved surface workability was evaluated in the same manner. As a result, none of the ductile pastes had cracks or poor conduction, and had practically satisfactory electrical properties for a three-dimensional curved printed circuit board.

<Application Example 13> The polycarbonate (PC) film in Application Example 11 was replaced with a polyethylene naphthalate "Tenonex" (manufactured by Teijin DuPont Co., Ltd.) with a thickness of 125 μm, and the following is the same Operate to obtain a curved printed circuit board with a three-dimensional shape. The obtained circuit pattern has no disconnection and no conduction failure. Hereinafter, the ductile conductive pastes obtained in Examples 12 to 18 were used in the same manner, and the curved surface workability was evaluated in the same manner. As a result, none of the ductile pastes had cracks or poor conduction, and had practically satisfactory electrical properties for a three-dimensional curved printed circuit board.

<Example 21> As the resin binder (A), 500 parts of phenoxy resin PKHC manufactured by InChem Corporation (containing dipropylene glycol monomethyl ether (400 parts) for the organic solvent (C)) was used as a conductive powder (B) flake silver powder (D50=3.5μm) 1000 parts, diurea type blocked isocyanate model 7960 (manufactured by Baxenden) as hardener (E) 15 parts, KS1260 as hardening catalyst 2 parts, carbon 10 parts of black powder, 10 parts of propylene glycol as the second solvent, and 20 parts of ethylene glycol acetate as other organic solvents are blended, and dispersed twice by a cooled three-roller kneader. Then, the obtained conductive paste was printed on the PE film and the PC film with predetermined patterns, and then dried in a hot air dryer at 130° C.×30 minutes to obtain a conductive film. Then, physical properties such as specific resistance and adhesion were measured and evaluated using this conductive film. The evaluation results are shown in Table 4-1 and Table 4-2.

<Examples 22-30> The resin and the mixing ratio of the conductive paste were changed, and Examples 22-30 were implemented. The compounding ratio and evaluation results of the conductive paste are shown in Table 4-1 and Table 4-2. The examples were evaluated for good coating film physical properties and no chemical attack.

In addition, in Table 4-1 and Table 4-2, binder resin, conductive powder, organic solvent, carbon, and other blends are listed below. Binder resin A (1): Phenoxy resin PKHC manufactured by InChem Corporation (weight average molecular weight: 43,000 glass transition temperature: 67°C) Binder resin A (2): Phenoxy resin PKHH" manufactured by InChme Corporation (weight average molecular weight: 57,000 glass transition temperature: 70°C), adhesive resin A (3): acrylic resin Olicox KC-7000 manufactured by Kyoeisha Chemical Co., Ltd. (weight average molecular weight: 30.000 glass transition temperature: 56°C) adhesive resin A (4): polyester Resin (manufactured by Toyobo Co., Ltd.) Vylon GK890 (weight average molecular weight: 17.000 glass transition temperature: 20°C) Binder resin A (5): polyvinyl acetal resin manufactured by Sekisui Chemical Co., Ltd. BM-5 (weight average molecular weight: 53,000 Glass transition temperature: 67°C) Adhesive resin A(6): Polyvinyl acetal resin Sekisui Chemical Co., Ltd. BH-6 (weight average molecular weight: 92,000 Glass transition temperature: 67°C) Adhesive resin A(7): Polyurethane resin Desmocoll 500 manufactured by Sumitomo Bayer (weight average molecular weight: 97,000 glass transition temperature: 47°C) Conductive powder B(1): Chip-like silver powder (D50: 3.5μm) Conductive powder B(2) : Spherical silver powder (D50: 1.4μm) Organic solvent C(1): Dipropylene glycol monomethyl ether (Haisorubu DPM) manufactured by Toho Chemical Co., Ltd. Organic solvent C(2): 3-Methoxy-manufactured by Kuraray Co., Ltd. 3-Methyl-1-butanol (Solfit) Second organic solvent (1): Propylene glycol (industrial propylene glycol) manufactured by Adeka Co., Ltd. Second organic solvent (2): 1,3-Butane manufactured by Sankyo Chemical Co., Ltd. Diol (1,3 butanediol) Other organic solvents (1): Daicel (stock) ethylene glycol acetate (EDGAC) Other organic solvents (2): Sankyo Chemical (stock) diacetone alcohol Other organic solvents (3): Dibasic acid ester (DBE) made by Invista. Carbon black powder (1): Ketjen black (ECP-600JP) made by LION. Hardener D (1): Diurea type blocked isocyanate model 7960 (manufactured by Baxenden) Hardener D (2): Adduct type blocked isocyanate DURANATE "E402-B80B (manufactured by Asahi Kasei Co., Ltd.) Hardener D (3): Epoxy compound EX-314 manufactured by Nagasechemtex Co., Ltd. Hardening touch Medium: KS1260 manufactured by Common Pharmaceutical Co., Ltd. Dispersant: Disperbyk193 manufactured by BYK Additive: BYK-410 manufactured by BYK

<Comparative Examples 21 and 22> In accordance with the components and ratios shown in Table 4-1 and Table 4-2, a silver paste was prepared in the same manner as in the examples, and a coating film was prepared using PC film and PET film as substrates. The physical properties of the coating film were measured and evaluated in the same manner as in the examples. The evaluation results are shown in Table 2-1 and Table 2-2.

From Examples 21-30 and Comparative Examples 21-22, it can be seen that the ductile conductive paste of the present invention has good ductility, good adhesion to the substrate, and excellent conductivity.

<Application Example 21> Using the ductile conductive paste obtained in Example 1 on a polycarbonate (PC) film (FE-2000 manufactured by Mitsubishi Gas Chemical Co., Ltd.) with a thickness of 400 μm, the predetermined circuit pattern was printed to dry The film thickness is 15μm±3μm, and it is dried under predetermined conditions. Secondly, the obtained polycarbonate film with circuit pattern is curved using a male/female mold with a diameter of 30mm in a hemispherical shape. The obtained circuit pattern has no disconnection and no conduction failure. Hereinafter, the ductile conductive pastes obtained in Examples 22 to 30 were used in the same manner, and the curved surface workability was evaluated in the same manner. As a result, none of the ductile pastes had cracks or poor conduction, and had practically satisfactory electrical properties for a three-dimensional curved printed circuit board.

<Application Example 22> The polycarbonate (PC) film in Application Example 21 was replaced with an easily moldable polyester film "SOFTSHINE" (manufactured by Toyobo Co., Ltd.) with a thickness of 188 μm, and the following operations were performed in the same way to obtain a three-dimensional Shaped curved printed circuit board. The obtained circuit pattern has no disconnection and no conduction failure. Hereinafter, the ductile conductive pastes obtained in Examples 22 to 30 were used in the same manner, and the curved surface workability was evaluated in the same manner. As a result, none of the ductile pastes had cracks or poor conduction, and had practically satisfactory electrical properties for a three-dimensional curved printed circuit board.

<Application Example 23> The polycarbonate (PC) film in Application Example 21 is replaced with a polyethylene naphthalate "Tenonex" (manufactured by Teijin DuPont Co., Ltd.) with a thickness of 125 μm, and the following is the same Ground operation to obtain a three-dimensional curved printed circuit board. The obtained circuit pattern has no disconnection and no conduction failure. Hereinafter, the ductile conductive pastes obtained in Examples 22 to 30 were used in the same manner, and the curved surface workability was evaluated in the same manner. As a result, none of the ductile pastes had cracks or poor conduction, and had practically satisfactory electrical properties for a three-dimensional curved printed circuit board.

【Table 1】

【table 2-1】

【Table 2-2】

【Table 3-1】

【Table 3-2】

【Table 4-1】

[產業利用性]【Table 4-2】

[Industrial Utilization]

Since the ductile conductive paste of the present invention does not crack or peel off the circuit pattern due to the deformation caused by heat and pressure of the laminated body with the circuit pattern, and the step of forming, it is used in the circuit chip and the printed circuit board with the three-dimensional structure. , Useful for the use of three-dimensional molded products with electrical circuits formed on the surface.

Claims (21)

A ductile conductive paste, characterized in that it contains a binder resin (A) composed of a thermoplastic resin, conductive powder (B), organic solvent (C), carbon black powder (D) and hardener (E), The organic solvent (C) is a glycol ether solvent or/and an alcohol solvent, and the carbon black powder (D) is contained in a range of 0.3 to 3.5% by weight relative to the total amount of the conductive powder (B). For example, the ductile conductive paste in the first item of the scope of patent application, wherein the boiling point of the organic solvent (C) is in the range of 100~300℃. For example, the ductile conductive paste of item 1 or 2 of the scope of patent application, in which the solvent containing the hydroxy group and the evaporation speed is slower than that of the organic solvent (C) is used as the second solvent. For example, the ductile conductive paste of item 1 or 2 of the scope of patent application, wherein the binder resin (A) is selected from polyester resins, polyurethane resins, epoxy resins, phenoxy resins, One or a mixture of two or more of the group consisting of vinyl chloride resin, cellulose derivative resin, polyvinyl acetal resin, and acrylic resin. For example, the ductile conductive paste of item 1 or 2 of the scope of patent application, wherein the glass transition temperature of the binder resin (A) is above 30°C and the number average molecular weight is in the range of 3000-150000. A method for manufacturing a curved printed circuit board is characterized by including the following steps: printing a ductile conductive paste as in any one of items 1 to 5 of the scope of patent application on a plastic substrate and thermally deforming the plastic substrate. A ductile conductive paste containing a binder resin (A) composed of thermoplastic resin, conductive powder (B), organic solvent (C), carbon black powder (D) and hardener (E), and is characterized by: The F value expressed by (parts by mass of conductive powder/parts by mass of components other than solvent)×100 is 75-95%, which is in the range of 0.3-3.5% by weight relative to the total amount of the conductive powder (B) Contains the carbon black powder (D). For example, the ductile conductive paste of item 7 of the scope of patent application, wherein the binder resin (A) is selected from polyester resins, polyurethane resins, epoxy resins, phenoxy resins, and vinyl chloride resins. One or a mixture of two or more of the group consisting of resin, cellulose derivative resin, polyvinyl acetal resin, and acrylic resin. For example, the ductile conductive paste of item 7 or 8 of the scope of patent application, wherein the glass transition temperature of the binder resin (A) is above 20°C and the number average molecular weight is in the range of 3000-150000. For example, the ductile conductive paste of item 7 or 8 in the scope of patent application, wherein the organic solvent (C) is a glycol ether solvent or/and an alcohol solvent. For example, the ductile conductive paste of item 7 or 8 of the scope of patent application, wherein the boiling point of the organic solvent (C) is in the range of 100~300℃. For example, the ductile conductive paste of the 7th or 8th item of the scope of patent application, in which the solvent containing a hydroxyl group has a slower evaporation rate than the organic solvent (C) as the second solvent. A method for manufacturing a curved printed circuit board, which is characterized by including the following steps: After printing the malleable conductive paste as any one of items 7 to 12 in the scope of the patent application on the plastic substrate, the plastic substrate is thermally deformed. A ductile conductive paste containing a binder resin (A) composed of a thermoplastic resin, conductive powder (B), organic solvent (C), carbon black powder (D) and hardener (E), and is characterized by : The binder resin (A) is selected from polyester resins, polyurethane resins, epoxy resins, phenoxy resins, vinyl chloride resins, cellulose derivative resins, polyvinyl acetal resins, One or more of the group consisting of acrylic resin contains the carbon black powder (D) in a range of 0.3 to 3.5% by weight relative to the total amount of the conductive powder (B), and the hardener (E ) Is either one or both of blocked isocyanate or epoxy compound. For example, the ductile conductive paste of item 14 of the scope of patent application, wherein the organic solvent (C) is a glycol ether solvent or/and an alcohol solvent. For example, the ductile conductive paste of the 14th or 15th patent application, wherein the boiling point of the organic solvent (C) is in the range of 100~300℃. For example, the ductile conductive paste of the 14th or 15th patent application, which contains a solvent containing a hydroxyl group which has a slower evaporation rate than the organic solvent (C) as the second solvent. For example, the ductile conductive paste of item 14 or 15 of the scope of patent application, wherein the hardener (E) is at least one blocked isocyanate selected from the group consisting of diurea type, trimer type, and adduct type. For example, the ductile conductive paste of item 14 or 15 in the scope of patent application, wherein the hardener (E) is a glycerin-type epoxy resin. For example, the ductile conductive paste of item 14 or 15 of the scope of patent application, wherein the glass transition temperature of the binder resin (A) is above 30°C and the number average molecular weight is in the range of 3000-150000. A method for manufacturing a curved printed circuit board is characterized by including the following steps: printing a ductile conductive paste as in any one of items 14 to 20 in the scope of patent application on a plastic base material and thermally deforming the plastic base plate.