KR101582407B1 - Metal ink composition having low viscosity and laminate sheet, flexible metal-clad laminate and printed circuit board using the same - Google Patents

Abstract

The present invention relates to a low viscosity metal ink composition capable of forming a seed layer excellent in adhesion to a polyimide film, a laminate sheet using the same, a flexible metal foil laminate, and a printed circuit board.

Description

Technical Field [0001] The present invention relates to a low-viscosity metal ink composition, a laminated sheet using the same, a flexible metal-clad laminate, and a printed circuit board,

The present invention relates to a low viscosity metal ink composition capable of forming a seed layer excellent in heat-resistant adhesion to a polyimide film, a laminated sheet using the same, a flexible metal foil laminate, and a printed circuit board.

Printed Circuit Board (PCB) is a wiring diagram that expresses electrical wiring to connect various parts according to circuit design. It connects and supports various parts. Such a printed circuit board may be a rigid printed circuit board, a flexible printed circuit board, a rigid-flexible printed circuit board coupled to the rigid printed circuit board, a rigid-flexible printed circuit board similar to a rigid- It is divided into printed circuit board.

Particularly, a flexible copper clad laminate (FCCL), which is a raw material of a flexible printed circuit board, is a laminate of a polymer film and a copper foil, and the demand thereof is rapidly increasing due to downsizing, thinning, high density and light weight of electronic devices.

As a manufacturing method of the flexible copper-clad laminate, there is known a casting method in which a liquid polyimide is coated and dried on a copper foil, and a lamination method in which a copper foil is laminated on a polyimide film coated with an adhesive or the like and then press-processed. However, such a production method is limited in the kind of the polyimide film, the kind of the copper foil and the adhesive. Particularly, in the case of a flexible copper-clad laminate produced by using an adhesive, it is difficult to form a fine circuit pattern in addition to problems such as flexibility and heat resistance.

Accordingly, a manufacturing method using a vacuum deposition method has been developed in order to solve the above-mentioned problems. For example, there is a method in which nickel, chromium, or a mixture thereof is vacuum-deposited on a polyimide film, and then a copper layer is formed thereon by electrolytic plating. However, due to the characteristics of the FPCB process, it is subjected to several heat treatment processes after the etching process, which is a circuit forming process. As a result of this heat treatment process, an oxide layer of copper is formed at the interface between the polyimide film and the metal, thereby deteriorating the heat-resistant adhesive force, thereby making it difficult to realize a microcircuit pattern. In addition, since the vacuum evaporation method is used, there has been a problem that the process cost is increased and the productivity is lowered.

Korean Patent Publication No. 10-2009-0081908

Disclosure of the Invention An object of the present invention is to provide a low viscosity metal ink composition capable of forming a seed layer excellent in chemical resistance, heat resistance and adhesion reliability with excellent heat-resistant adhesion to a polyimide film, and a flexible metal foil laminate and a printed circuit board .

(A) metal nanoparticles capped by a C ₁ -C ₂₀ carboxylate-based ligand and a C ₁ -C ₂₀ primary amine-based ligand; (b) two or more kinds of binder resins including an epoxy resin and a phenoxy resin; (c) a nonpolar organic solvent; (d) a mixed ether solvent containing an aromatic ether solvent and an aliphatic ether solvent; (e) a curing agent; And (f) a dispersing agent.

The present invention also relates to a polyimide film; And a seed layer formed on one side or both sides of the polyimide film, the seed layer being formed from the low viscosity metal ink composition described above.

The present invention also relates to a polyimide film; A seed layer formed on one side or both sides of the polyimide film with the low viscosity metal ink composition described above; And a plating layer formed on an opposite surface of the seed layer surface in contact with the polyimide film.

In addition, the present invention provides a printed circuit board comprising a seed layer formed from the low viscosity metal ink composition described above.

INDUSTRIAL APPLICABILITY The low viscosity metal ink composition according to the present invention is excellent in dispersion stability and is not only uniformly coated but also has excellent heat resistant adhesion with polyimide film and excellent in chemical resistance, heat resistance, corrosion resistance, adhesion reliability, A seed layer can be formed.

Therefore, when the flexible metal film laminate and the printed circuit board are manufactured using the low viscosity metal ink composition, a seed layer having excellent properties such as heat-resistant adhesive property, heat resistance, corrosion resistance, adhesion reliability, and bending property is formed, Can be implemented.

1 is a cross-sectional view showing a laminated sheet according to the present invention.
2 is a cross-sectional view illustrating a flexible metal foil laminate according to an example of the present invention.
3 is a cross-sectional view illustrating a flexible metal foil laminate according to another example of the present invention.
FIG. 4 is a focused ion beam (FIB) photograph showing a cross section of the flexible copper-clad laminate produced in Example 1. FIG.
5 is a view showing a reflow process performed in the first embodiment.

Hereinafter, the present invention will be described in detail.

The present invention relates to a low viscosity metallic ink composition capable of the adhesive strength and electrical conductivity to form a high seed layer, (a) a primary amine-based ligands of C ₁ ~ C ₂₀ carboxylate-based ligand and a C ₁ ~ C ₂₀ of Metal nanoparticles capped by the metal nanoparticles; (b) two or more kinds of binder resins including an epoxy resin and a phenoxy resin; (c) a nonpolar organic solvent; (d) a mixed ether solvent containing an aromatic ether solvent and an aliphatic ether solvent; (e) a curing agent; And (f) a dispersing agent.

The low viscosity metal ink composition is excellent in dispersion stability and can form a seed layer having a uniform thickness by a roll-to-roll coating method. The seed layer formed at this time is excellent in heat-resistant adhesion with a polyimide film, It has excellent properties such as impact resistance, abrasion resistance, and chemical resistance. Therefore, when the flexible metal film laminate and the printed circuit board are produced by using the low viscosity metal ink composition of the present invention, a seed layer having excellent properties such as heat-resistant adhesiveness, heat resistance, corrosion resistance, adhesion reliability, A microcircuit pattern of one thickness can be realized.

The metal nanoparticles are nano-sized metal particles capped by a C ₁ -C ₂₀ carboxylate-based ligand and a C ₅ -C ₂₀ primary amine-based ligand. Here, the carboxylate-based ligand and the primary amine-based ligand are both bound to or adsorbed on the particle surface during the production of the metal nanoparticles to prevent aggregation between the particles due to instability of the surface, thereby increasing the dispersibility of the capping ligand )to be. The metal nanoparticles are capped by such a ligand, so that the metal nanoparticles can be stably self dispersed.

Also, the primary amine-based ligand in the capping ligand can cure the epoxy resin. The metal nanoparticles capped by such primary amine-based ligands can self-disperse in non-polar organic solvents due to primary amine-based ligands. In addition, the primary amine-based ligand is excellent in compatibility with a mixed ether solvent containing an aromatic ether solvent and an aliphatic ether solvent. Here, the mixed ether solvent can be mixed well with the alcoholic solvent, and the epoxy resin added for imparting the adhesive force can be dissolved and uniformly dispersed. Therefore, the metal nanoparticles to which the primary amine-based ligand is bound or adsorbed are dispersed by the nonpolar organic solvent, and compatibility with the epoxy resin and the phenoxy resin can be improved by the mixed ether solvent. Accordingly, when forming a thin film circuit pattern, the metal nanoparticles can be bonded to the surface of a substrate through two or more kinds of binder resins including an epoxy resin and a phenoxy resin, Can be improved.

In addition, since the size of the metal nanoparticles becomes smaller as the number of carbon atoms of the carboxylate-based ligand and the primary amine-based ligand bound or adsorbed on the surface of the metal nanoparticles increases, the metal nanoparticles have properties of apolar material, Therefore, it is possible to form a uniform thin film circuit pattern on the substrate by improving the compatibility with the epoxy resin and the phenoxy resin and improving the dispersion stability.

However, in the case of the phenoxy resin, the epoxy resin easily dissolves and is uniformly dispersed in the nonpolar solvent, whereas when the hydrocarbon solvent such as toluene or xylene is used as the nonpolar organic solvent, the dispersibility of the epoxy resin is lowered . Accordingly, the present invention includes a mixed ether-based solvent containing an aromatic ether solvent and an aliphatic ether solvent to disperse the metal nanoparticles and the phenoxy resin while dispersing the epoxy resin, Dispersing agent.

In addition, the phenoxy resin has a higher molecular weight than the epoxy resin, has high toughness, abrasion resistance, hardness, chemical resistance, and adhesion. Therefore, the low viscosity metal ink composition of the present invention can form a seed layer having excellent abrasion resistance and adhesion property by including a phenoxy resin, and it is possible to prevent the damage of the seed layer to the plating liquid during formation of the plating layer, Peeling between the seed layer and the plating layer can be prevented.

As described above, in order to form a thin film circuit pattern having excellent adhesion properties with a substrate without a surface treatment process of the substrate while maintaining dispersion stability, the low viscosity metal ink composition of the present invention comprises (a) a C ₁ to C ₂₀ carboxyl Metal nanoparticles capped by a rate-based ligand and a C ₁ -C ₂₀ primary amine-based ligand; (b) two or more binder resins including a phenoxy resin and an epoxy resin; (c) a nonpolar organic solvent; (d) a mixed ether solvent containing an aromatic ether solvent and an aliphatic ether solvent; (e) a curing agent; And (f) a dispersant.

<Low Viscosity Metal Ink Composition>

Hereinafter, each component of the low viscosity metal ink composition according to the present invention will be described.

(a) metal nanoparticles

The low viscosity metal ink composition of the present invention comprises metal nanoparticles. The metal nanoparticles are capped by a C ₁ -C ₂₀ carboxylate-based ligand and a C ₅ -C ₂₀ primary amine-based ligand. Specifically, the metal nanoparticles include a metal core, a carboxylate-based ligand of C ₁ to C ₂₀ , and a primary amine-based ligand of C ₅ to C ₂₀ , and the carboxylate-based ligand and the primary amine-based ligand Each of the ligands is bonded or adsorbed to the surface of the metal core. Since these metal nanoparticles are nano-sized in size, the ratio of surface atoms to total atoms is greatly increased as compared with that of bulk metals. As a result, the nanoparticles become unstable and the melting point is lowered. Since the crystal grains and the grain boundaries are formed by secondary recombination, the contact area with the substrate is increased, so that a thin film circuit pattern having excellent conductivity and adhesion to the polymer substrate can be formed. The metal nanoparticles are excellent in compatibility with two or more kinds of binder resins including an epoxy resin and a phenoxy resin by a mixed ether solvent containing an aromatic ether solvent and an aliphatic ether solvent as described above Therefore, a thin film circuit pattern having excellent adhesion to a substrate can be realized by two or more kinds of binder resins including an epoxy resin and a phenoxy resin.

Examples of the metal nanoparticles include, but are not limited to, nanoparticles of metals selected from the group consisting of Group 1 to Group 14 on the periodic table, preferably gold, silver, copper, nickel, platinum, cobalt, palladium, There are nanoparticles of aluminum, tin, zinc, iron, indium and magnesium, and more preferably silver nanoparticles. These may be used alone or in combination of two or more.

Such metal nanoparticles are capped by a C ₁ -C ₂₀ carboxylate-based ligand and a C ₅ -C ₂₀ primary amine-based ligand.

The C ₁ -C ₂₀ carboxylate ligand is a capping ligand having a structure of R-COO ^- , wherein R is a C ₁ to C ₂₀ saturated or unsaturated aliphatic hydrocarbon group, preferably a C ₈ to C ₁₅ A saturated or unsaturated aliphatic hydrocarbon group), and the dispersion stability of the metal nanoparticles can be improved by preventing agglomeration between particles. In addition, depending on the type of the carboxylate ligand, the size of the metal nanoparticles may be controlled to affect the adhesion characteristics and the conductivity of the thin film circuit pattern. Particularly, as the carbon number of the carboxylate-based ligand increases, the particle size can be controlled to be small and the firing can be performed at a temperature as low as about 200 to 250 ° C. Thus, a thin film circuit pattern having high adhesion and conductivity on a polymer substrate is realized .

Examples of such carboxylate-based ligands include oxanonate ligands, nonanoate ligands, decanoate ligands, dodecanoate ligands, oleate ligands, ligand), but are not limited thereto.

The primary amine-based ligand is a capping ligand having a structure of C _n H _{2n + 1} NH ₂ (where n is from 5 to 20, preferably from 10 to 18) to prevent aggregation between particles and increase solubility Not only the dispersion stability of the metal nanoparticles is improved but also the compatibility between the metal nanoparticles and two or more kinds of binder resins (including epoxy resin and phenoxy resin) can be improved. In addition, the primary amine-based ligand can accelerate the curing of the epoxy resin and may affect the heat treatment temperature of the metallic ink composition coated on the substrate in the future. Examples of such primary amine-based ligands include, but are not limited to, octylamine ligand, decylamine ligand, dodecylamine ligand, and oleylamine ligand.

The average particle diameter of the metal nanoparticles capped by such ligands is not particularly limited. However, when the size of the metal nanoparticles is about 1 to 20 nm, the melting temperature is lowered due to the size effect of the nanoparticles. Therefore, the particles are melted even at a temperature as low as about 200 DEG C, , High conductivity can be realized and the contact area with the substrate can be increased through the recombination of the metals connected to each other, thereby achieving high adhesion.

The content of the metal nanoparticles is not particularly limited and may be controlled in consideration of the thickness of the seed layer to be formed. However, in the case of the present invention, as the content of the metal nanoparticles increases, the content of the mixed binder resin increases to increase the viscosity of the metal ink composition. Therefore, when the content of the metal nanoparticles is about 30 to 80% by weight, preferably about 30 to 70% by weight, and more preferably about 40 to 60% by weight based on the total weight of the metal ink composition, The viscosity can be adjusted as low as about 5 to 500 cps. Further, since the metal nanoparticles are melted and there is less change in the surface area before and after the recombination at the time of recombination, less voids are formed in the metal portion forming the pattern. A thin film circuit pattern can be formed.

Such metal nanoparticles can be prepared by various methods.

According to one embodiment of the invention, the metal nanoparticles are reacted with a C ₁ ~ C ₂₀ carboxylic acid or salt thereof of the metal salt by forming a metal carboxylate of a _{C 1 ~ C 20 (S100)} ; A metal carboxylate of a C ₁ ~ C _20, to form a metal carboxylate complex of C ₅ ~ C ₂₀ with C ₁ ~ C ₂₀ The primary amine of the C ₅ ~ C ₂₀ bond is reacted with a primary amine of (S200); And forming a metal nanoparticle by adding a reducing agent to the C ₁ -C ₂₀ metal carboxylate complex to which the C ₅ to C ₂₀ primary amine is bonded (S300). However, the present invention is not limited thereto .

In the preparation of the metal nanoparticles, the method may further include washing the metal nanoparticles produced in step S300 by immersing the metal nanoparticles in alcohol, and then filtering the metal nanoparticles.

First, the S100 step is reacted with a carboxylic acid or its salt of C ₁ ~ C ₂₀ metal salt to form a metal carboxylate of a C ₁ ~ C _20. Specifically, when the carboxylic acid or its salt of the C ₁ ~ C ₂₀ metal salt and reacting the C ₁ ~ C ₂₀ carboxylic acid or salt of acid anion thereof ^{(R-COO -, R =} C 1 ~ C 20 saturated or unsaturated An aliphatic hydrocarbon group, preferably a C ₈ to C ₁₅ saturated or unsaturated aliphatic hydrocarbon group) and a metal cation of the metal salt react to form a C ₁ to C ₂₀ metal carboxylate.

According to one example of the present invention, when decanoic acid is reacted with sodium hydroxide (NaOH), sodium decanoate is produced, and when sodium decanoate is reacted with silver nitrate (AgNO ₃ ), white precipitates such as Ag- Salt [CH ₃ (CH ₂ ) ₈ -COO ^- Ag ⁺ ] is produced.

The C ₁ -C ₂₀ carboxylic acid which can be used in the present invention is a compound having the structure of R-COOH (wherein R is a C ₁ -C ₂₀ saturated or unsaturated aliphatic hydrocarbon), for example, caprylic acid, But are not limited to, pelargonic acid, capric acid, lauric acid, oleic acid, and the like.

The C ₁ -C ₂₀ carboxylic acid may be a C ₁ -C ₂₀ carboxylic acid solution obtained by dissolving the first carboxylic acid in the first solvent. Here, the first solvent which can be used is not particularly limited as long as it is conventionally used in the art to dissolve a carboxylic acid-based substance. Nonlimiting examples of the first solvent include water, methanol, ethanol, propanol, isopropanol, butanol, pentanol, hexanol, dimethyl sulphoxide (DMSO), N, N-dimethylformamide dimethylformamide, DMF), ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol diethyl ether, propylene glycol, propylene glycol propyl ether, propylene glycol methyl ether acetate, N-methylpyrrole It is also possible to use N-methyl pyrrolidone, methyl isobutyl ketone, methyl ethyl ketone, acetonitrile, tetrahydrofuran (THF), hexadecane, pentadecane, tetradecane, tridecane, dodecane, undecane, decane, nonane, octane, heptane, hexane, xylene, toluene, benzene, 6-lutidine , Dichloromethane and the like, preferably methanol. These solvents may be used alone or in combination of two or more.

In addition, the C a carboxylic acid salt of ₁ ~ C ₂₀ is if the obtained by reacting a solution of the carboxylic acid obtained by dissolving the C ₁ ~ C ₂₀ carboxylic acids for reacting with a base or in the or a base to the second solvent is not particularly limited. Do not.

The metal ion of the metal salt can be easily bonded to the hydrogen sites of the carboxylic acid by the base, so that the metal carboxylate can be easily obtained. For example, when decanoic acid is reacted with sodium hydroxide, which is a base, sodium ions are bonded to the hydrogen sites of the decanoic acid, and water dissociated from the decanoic acid is combined with OH ^- of the sodium hydroxide. Thereafter, when silver nitrate is added thereto, the silver ions dissociated from the silver nitrate are bonded to the sodium site, so that the final metal carboxylate can be obtained.

Examples of such bases include, but are not particularly limited, for example, _{NaOH, NH 4 OH, NaHCO 3} , Na 2 CO 3, KOH, Ca (OH) 2, Ba (OH) 2, Mg (OH) 2, K 2 CO ₃ , KHCO ₃ , CaCO _3, and the like, but are not limited thereto.

At this time, the carboxylic acid and base of the C ₁ -C ₂₀ can be mixed and reacted at a molar ratio of carboxyl group: base metal ion of carboxylic acid = 0.5-1.5: 0.5-1.5. For example, when decanoic acid is reacted with sodium hydroxide to obtain a decanoic acid salt, sodium hydroxide can be added to the decanoic acid at the same molar ratio because the carboxyl group of the decanoic acid reacts with the sodium ion of the sodium hydroxide at a ratio of 1: 1 .

Examples of the second solvent for dissolving the base are not particularly limited as long as they are commonly used in the art, and they are the same as those of the first solvent described above, preferably water.

The metal salt usable in the present invention is not particularly limited and includes, for example, an inorganic salt of a metal selected from the group consisting of Group 1 to Group 14 on the periodic table, preferably gold, silver, copper, nickel, platinum, cobalt, There are inorganic salts such as aluminum, tin, zinc, iron, indium and magnesium, and more preferably inorganic salts such as silver. These inorganic salts may be used singly or in combination. Non-limiting examples of the inorganic salt include nitrates, sulfates, acetates, phosphates, silicates, hydrochlorides and the like.

Such a metal salt may be in a solution state obtained by dissolving in a third solvent. Here, examples of the usable third solvent are not particularly limited as long as they are commonly used in the art, and they are the same as those of the first solvent described above, and preferably water.

The mixing ratio of the metal salt and the carboxylic acid of C ₁ to C ₂₀ or its salt may be mixed at various ratios depending on the kind of the carboxylic acid or its salt used or the kind of the metal salt used. However, when a metal salt is added to the C ₁ -C ₂₀ carboxylic acid or its salt, a slurry is formed. When the molar concentration of the carboxylic acid is higher than the amount of the organic solvent or water used at that time, the amount of the metal carboxylate The viscosity is increased and the reaction is difficult to occur smoothly. Therefore, in consideration of the amount of solvent used for the acid or salt mixture ratio thereof of said _{C 1 ~ C 20 C 1 ~} C 20 carboxylic acid or a salt thereof: When adjusted to 0.5 to 1.5 molar ratio: metal = 0.5 to 1.5 A smooth reaction is induced between the C ₁ -C ₂₀ carboxylic acid or a salt thereof and the metal salt to increase the yield of the metal carboxylate.

On the other hand, in order to remove unreacted materials and water in the selectively generated C ₁ -C ₂₀ metal carboxylate salt, the metal carboxylate salt of C ₁ -C ₂₀ produced in the step S100 after completion of the reaction is washed with water, (E. G., Methanol), washed, and then dried in a vacuum oven at about 40-50 &lt; 0 &gt; C. By drying the metal carboxylate salt as described above, the precursor is easily dissociated when the following primary amine is added, so that the metal carboxylate and the primary amines can be bonded smoothly.

In step S200, the metal carboxylate of C ₁ -C ₂₀ formed in step S 100 is reacted with a C ₅ -C ₂₀ primary amine. As a result, the metal ion of the metal carboxylate of C ₁ -C ₂₀ Coordination of the C ₅ to C ₂₀ primary amine with the ligand results in the formation of a C ₁ to C ₂₀ metal carboxylate complex in which the C ₅ to C ₂₀ primary amine is bonded. The C ₁ -C ₂₀ carboxylic acid moiety and the C ₅ -C ₂₀ primary amine moiety of the resulting metal carboxylate complex can improve the dispersion stability of the metal nanoparticles in the metal ink composition, The compatibility with the binder resin is excellent by the solvent, and the adhesion property of the thin film circuit pattern can be improved.

According to one example of the present invention, when the Ag-carboxylic acid salt [CH ₃ (CH ₂ ) ₈ -COO ^- Ag ⁺ ] reacts with oleylamine, oleylamine is coordinated to the silver ion of the Ag- As shown in the following Formula 1, an Ag-carboxylic acid salt complex to which oleylamine is coupled can be obtained.

[Chemical Formula 1]

A primary amine of the C ₅ ~ C _20, while the role of solvent for increasing the metal carboxylate salt of the degree of dissociation of the C ₁ ~ C ₂₀ in the present invention, are coordinated to the metal carboxylate salt of a metal ion in the subsequent conductive ink composition And improves the compatibility between the metal nanoparticles and the epoxy resin. In addition, the primary amine may affect the heat treatment temperature of the metal ink composition in the future.

The primary amine which can be used is not particularly limited as long as it can dissociate and react with the metal carboxylate of C ₁ to C ₂₀ . However, in the case of a compound having a structure of C _n H _{2n + 1} NH ₂ (where n is 5 to 20, preferably 10 to 18), dispersion stability of metal nanoparticles in the metal ink composition may be improved In addition, the adhesion properties between the metal ink composition and the polyimide film are improved, so that a seed layer having a uniform thickness can be formed, and a thin film circuit pattern having a uniform thickness can be realized. Specific examples include, but are not limited to, octylamine, decylamine, dodecylamine, and oleylamine.

The mixing ratio of the above-mentioned metal carboxylate of C ₁ to C ₂₀ and the primary amine of C ₅ to C ₂₀ is not particularly limited, but when the molar ratio is 1 to 2: 1.8 to 3, the degree of dissociation of the metal carboxylate is increased The bonding between the metal carboxylate and the primary amine can be promoted.

Then, in step S300 to form a metal nano-particles by adding a reducing agent to the primary amine the metal carboxylate complexes in combination with C ₁ ~ C ₂₀ of C ₅ ~ C ₂₀ obtained in the above step S200. When the reducing agent is added to a C ₁ -C ₂₀ metal carboxylate complex to which a primary amine of C ₅ to C ₂₀ is bonded, metal ions of the metal carboxylate complex are reduced to metal atoms to form metal particles. However, the metal particles to be formed tend to aggregate with each other due to instability of the surface to form aggregates, but the C ₅ to C ₂₀ primary amine and the C ₁ to C ₂₀ carboxylate bound to the metal ion of the complex The metal particles are dispersed and formed into nano-sized metal particles as the metal particles are bonded or adsorbed on the surface of the metal particles to block cohesion between the metal particles. The C ₅ to C ₂₀ primary amine and C ₁ to C ₂₀ carboxylate act as ligands to bind or adsorb to the surface of the metal core, respectively, to cap the metal nanoparticles.

The reducing agent usable in the present invention is not particularly limited, and examples thereof include hydrogen compounds such as hydrogen, hydrogen iodide, hydrogen sulfide and aluminum hydride; Low-grade oxides such as carbon monoxide, dioxide, and the like; Lower sulfuric acid salts such as sulfite and sodium sulfide; A metal which is liable to become a positively positive electron, such as an alkali metal, magnesium, or zinc; Organic compounds having a low degree of oxidation such as aldehyde, saccharine, formic acid and oxalic acid, and amine compounds such as hydrazine, phenylhydrazine and 1-amino-4-methylpiperazine. Preferred are hydrazine, phenylhydrazine, 1- -4-methylpiperazine, and the like. These may be used alone or in combination of two or more.

The content of the reducing agent is not particularly limited, and it is adjusted in consideration of the size and yield of the metal nanoparticles. However, when the amount of the reducing agent is about 1 to 1.2 equivalents based on the metal in the metal carboxylate complex, the metal nanoparticle size can be adjusted to about 2 to 8 nm have.

Alternatively, the method may further include washing the metal nanoparticles produced in step S300 with alcohol, and then filtering the metal nanoparticles. If the metal nanoparticles of step S300 are immersed in alcohol, metal nanoparticles may be precipitated while the residual amine compound, carboxylic acid, and reducing agent are removed. Thereafter, the precipitated metal nanoparticles can be obtained through a filtration process such as a centrifugation process.

The metal nanoparticles prepared as described above are preferably mixed in a non-dried state when they are mixed with the components of the following ink composition. If the dried metal nanoparticles are mixed with the following components, agglomeration between the gold nanoparticles occurs, which may lower the dispersion stability of the ink composition, and it is difficult to obtain a conductive ink having a high concentration.

(b) two or more binder resins

The low viscosity metal ink composition of the present invention comprises two or more kinds of binder resins. The two or more kinds of binder resins include an epoxy resin and a phenoxy resin. In the present invention, by mixing an epoxy resin and a phenoxy resin as a binder resin as described above, the metal nanoparticles are excellent in compatibility with the metal nanoparticles, and the metal nanoparticles can be bonded to the surface of the polyimide film by the binder resins , Whereby the adhesion between the polyimide film and the plating layer is improved and a fine circuit pattern can be realized. In addition, the phenoxy resin has a higher molecular weight than the epoxy resin, and has high toughness, abrasion resistance, hardness, and chemical resistance. Therefore, the seed layer formed by the low viscosity metal ink composition is excellent in abrasion resistance, The copper layer can be less damaged by the plating solution in forming the copper layer. In addition, since the phenoxy resin is excellent in the adhesive force, a high adhesive force between the seed layer and the substrate is achieved after the plating process, and peeling between the seed layer and the substrate can be prevented. In addition, since the phenoxy resin improves the chemical resistance, impact resistance and abrasion resistance of the seed layer and the water absorption rate is as low as 0.2%, the dimensional stability of the seed layer is improved and the plating layer can be formed on the seed layer with a uniform thickness have.

The content of the two or more kinds of binder resins is not particularly limited, but it is about 0.4 to 10% by weight, preferably 1 to 8% by weight, more preferably 1.5 to 6% by weight based on the total weight of the low viscosity metal ink composition , A seed layer having a low specific resistance of about 3.3 x 10 &lt; ^-5 &gt; to 8.0 x 10 &lt; ^-4 &gt; OMEGA. Cm can be formed while having excellent adhesion to the polyimide film of 5B or more. As a result, the plating layer can be uniformly formed on the seed layer by electrolytic plating in the production of the flexible metal foil laminate, and the adhesion between the seed layer and the plating layer can be as high as about 0.8 to 1.0 kgf / cm.

Here, the content of the epoxy resin and the phenoxy resin is not particularly limited. However, if the content of the phenoxy resin exceeds 3 parts by weight based on 100 parts by weight of the metal nanoparticles, the flexibility of the laminated board or the printed circuit board may be reduced. Therefore, when the content of the epoxy resin is controlled to about 1 to 4 parts by weight and the content of the phenoxy resin is controlled to about 0.5 to 3 parts by weight based on 100 parts by weight of the metal nanoparticles, It is possible to prevent the lowering of the flexibility of the printed circuit board. According to one example, 3.75 parts by weight of an epoxy resin and 1.25 parts by weight of a phenoxy resin can be mixed and used based on 100 parts by weight of the Ag nanoparticles.

As the epoxy resin usable in the present invention, any conventional epoxy resin known in the art can be used without limitation, and preferably two or more epoxy groups are present in one molecule.

Examples of usable epoxy resins include, but are not limited to, bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, novolak epoxy resin, flame retardant epoxy resin, flame retardant epoxy resin, cycloaliphatic epoxy resin, Rubber-modified epoxy resins, alkylphenol novolak-type epoxy resins, biphenyl-type epoxy resins, Aralkyl type epoxy resins, naphthol type epoxy resins and dicyclopentadiene type epoxy resins. Or a mixture of two or more of them may be used. Preferably, when the bisphenol A type epoxy resin and the novolak type epoxy resin are used together with the phenoxy resin, the heat resistance adhesiveness of the seed layer can be further improved.

Specific examples thereof include epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, naphthalene type epoxy resin, anthracene epoxy resin, biphenyl type epoxy resin, tetramethyl biphenyl type epoxy resin, Epoxy resin, cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, bisphenol S novolak type epoxy resin, biphenyl novolac type epoxy resin, naphthol novolak type epoxy resin, naphthol phenol coaxial novolak type epoxy resin, Naphthol cholesterol co-novolak type epoxy resin, aromatic hydrocarbon formaldehyde resin modified phenol resin type epoxy resin, triphenyl methane type epoxy resin, tetraphenyl ethane type epoxy resin, dicyclopentadiene phenol addition reaction type epoxy resin, phenol aralkyl type An epoxy resin, a polyfunctional phenol resin, a naphthol aralkyl type epoxy resin, etc. They, they, alone or in combination of two or more can be mixed and used.

The epoxy equivalent of the epoxy resin is not particularly limited, but if it is about 1,000 to 3,000 g / eq, adhesion properties between the substrate and the circuit pattern can be further improved. However, in the case of an epoxy resin, the smaller the molecular weight, the better the heat resistance, and the higher the molecular weight, the better the plasticity. In addition, the smaller the molecular weight of the epoxy resin, the higher the density of the three-dimensional cross-linked structure formed at the time of curing becomes, and the adhesive force of the resin may be lowered. Therefore, when two or more kinds of epoxy resins differing in the equivalent are mixed, the balance between hardness and plasticity of the epoxy resin cured product is controlled, and the adhesive force of the epoxy resin can be maintained.

The phenoxy resin which can be used in the present invention is not particularly limited as long as it is known in the art. Examples thereof include bisphenol-type phenoxy resins, naphthalene-type phenoxy resins, biphenyl-type phenoxy resins, and modified phenoxy resins, which may be used alone or in combination of two or more.

Specific examples thereof include bisphenol A type phenoxy resin, bisphenol A type / bisphenol F type phenoxy resin, bromine type phenoxy resin, phosphorus type phenoxy resin, bisphenol A type / bisphenol S type phenoxy resin, caprolactone modified phenoxy and the like However, the present invention is not limited thereto. These may be used alone or in combination of two or more.

The average molecular weight of the phenoxy resin is not particularly limited, but when the number average molecular weight is about 9,000 to 20,000 and the weight average molecular weight is 30,000 to 60,000, the viscosity of the metal ink composition is controlled to be low to improve workability and coatability In addition, the heat resistance of the seed layer can be further improved.

(c) a nonpolar organic solvent

The low viscosity metal ink composition of the present invention comprises a nonpolar organic solvent. The nonpolar organic solvent can disperse the metal nanoparticles to improve the dispersion stability of the ink composition, and furthermore, the viscosity of the ink composition can be controlled.

Examples of such apolar organic solvent include hydrocarbon solvents having 5 to 20 carbon atoms or alcohol solvents having 6 to 15 carbon atoms, but are not limited thereto. Here, the alcoholic solvent having 6 to 15 carbon atoms is a boiling point solvent having a boiling point of about 150 ° C or higher, preferably 150 to 350 ° C. As the number of carbon atoms increases from 6 to 15, the molecular weight of the alcoholic solvent increases, And thus has properties close to non-polarity.

Specific examples of the hydrocarbon-based solvent having 5 to 20 carbon atoms include toluene, xylene, hexane, tetradecane, octadecene, and the like. Non-limiting examples of the alcohol- Examples thereof include heptanol, octanol, 2-ethyl-1-hexanol, decanol, dodecanol and the like, with preference given to octanol or 2-ethyl-1-hexanol, Can be mixed and used.

The content of the non-polar organic solvent is not particularly limited and is a residual amount adjusted so that the total amount of the ink composition becomes 100% by weight.

However, when a hydrocarbon-based solvent such as toluene or xylene is used as the apolar organic solvent, the dispersibility of the epoxy resin in the ink composition may be deteriorated. Accordingly, in order to disperse the metal nanoparticles and the phenoxy resin and to stably disperse the epoxy resin, the low viscosity metal ink composition of the present invention comprises the following aromatic ether-based solvent capable of dispersing the epoxy resin together with the apolar organic solvent and And a mixed ether-based solvent containing an aliphatic ether-based solvent. At this time, the mixing ratio of the nonpolar organic solvent for dispersing the metal nanoparticles and the mixed ether solvent for dispersing the epoxy resin is not particularly limited. However, when the blending ratio of the nonpolar organic solvent and the mixed ether solvent is 30 to 70: 70 to 30, the dispersion stability of the metal nanoparticles and the epoxy resin is improved and the viscosity of the metal ink composition is 5 to 500 cps The low viscosity metal ink composition of the present invention can be applied to a seed layer having a uniform thickness of about 1 mu m or less through roll-to-roll coats such as microgravure coating, slot die coating, So that a fine circuit pattern of uniform thickness can be realized.

(d) mixed ether solvent

The low viscosity metal ink composition according to the present invention includes an ether solvent (hereinafter referred to as a 'mixed ether solvent') in which an aromatic ether solvent and an aliphatic ether solvent are mixed. The mixed ether solvent can disperse the metal nanoparticles and simultaneously disperse two or more kinds of binder resins including an epoxy resin and a phenoxy resin uniformly to improve the dispersion stability of the ink composition and further improve the viscosity of the ink composition Can be adjusted.

Non-limiting examples of the aromatic ether solvent include an aromatic ether solvent containing a C ₁ -C ₆ alkoxy group, and specific examples thereof include methoxybenzene (Anisole) and the like, but are not limited thereto.

Examples of the aliphatic ether solvent include aliphatic ether solvents containing a C ₁ -C ₆ alkoxy group. Specific examples thereof include diethylene glycol monobutyl ether acetate (BCA), diethylene glycol monobutyl ether acetate But are not limited to, dimethyl ether, diethyl ether, dibutyl ether, dipropyl ether, diisopropyl ether, di-n-propyl ether and di-n-butyl ether.

The content of the mixed ether solvent is not particularly limited. When the content of the mixed ether solvent is about 10 to 25% by weight, preferably about 20 to 25% by weight based on the total weight of the metal ink composition, the dispersibility of the two or more binder resins As the ink composition is improved, the viscosity of the ink composition can be adjusted to about 5 to 500 cps.

In this case, the mixing ratio of the aromatic ether solvent to the aliphatic ether solvent is not particularly limited, but when the ratio is 60 to 80:40 to 20, the dispersibility of the metal nanoparticles and the binder resin of two or more kinds is further improved And the dispersion stability of the ink composition can be further improved.

(e)

The low viscosity metal ink composition according to the present invention comprises a curing agent. The curing agent can be used without limitation as long as it is a conventional curing agent known in the art that can undergo a curing reaction with two or more kinds of binder resins (containing an epoxy resin and a phenoxy resin). Two or more kinds of binder resins (epoxy resin and phenoxy resin And the like).

Examples of the curing agent include amine-based curing agents such as an amine, an aliphatic amine, a modified aliphatic amine, and an aromatic amine, a phthalic anhydride curing agent, a polyamide resin Polyamide, polysulfide, amine complex, phenol resin, dicyanamide, and the like.

The content of such a curing agent is not particularly limited and can be appropriately adjusted depending on the total content of two or more kinds of binder resins (including epoxy resin and phenoxy resin). For example, the content of the curing agent may be about 0.1 to 3% by weight based on the total weight of the metal ink composition. When the above-mentioned curing agent and two or more kinds of binder resins are mixed in an equivalent ratio of 1: 1000 to 3000, it is preferable that the heat-resistant adhesive strength of the seed layer can be further improved.

(f) Dispersant

The low viscosity metal ink composition according to the present invention comprises a dispersant. By including the dispersant, dispersion stability of the metal nanoparticles and two or more kinds of binder resins (particularly, epoxy resin) can be improved, and a uniform thin film circuit pattern can be formed. Also, the dispersing agent can prevent the metal nanoparticles from aggregating in the storage of the metal ink composition, thereby improving the storage stability of the ink composition.

Examples of the dispersing agent include conventional dispersing agents known in the art, and examples thereof include polymeric or low molecular weight wetting and dispersing agents such as fatty acid-based or phosphate ester-based compounds, and specifically DISPERBYK-110, DISPERBYK-111 , DISPERBYK-102, and the like.

The content of such a dispersant is not particularly limited, but when it is about 1 to 5% by weight based on the metal ink composition, the dispersion stability and storage stability of the metal nanoparticles can be further improved.

(g) Curing accelerator

The low viscosity metal ink composition of the present invention may optionally further comprise a curing accelerator. The curing accelerator is not particularly limited as long as it can appropriately control the curing rate of two or more kinds of binder resins (including epoxy resin and phenoxy resin), and can control the speed of the curing agent.

Examples of the curing accelerator include imidazole-based curing accelerators and derivatives thereof.

Non-limiting examples of the imidazole-based curing accelerators include 1-methylimidazole, 2-methylimidazole, 2-ethylimidazole, 2-decylimidazole, 2-heptylimidazole, Ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2 Methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl- 2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecyl-imidazole trimellitate, 1-cyanoethyl- (2'-methylimidazole- (1 ')) -ethyl-s-triazine, 2,4-diamino-6- (1 ')) - ethyl-s-triazine, 2,4-diamino-6- (2'-undecylimidazole- , 2-pheyl-4,5-dihydroxymethylimidazole, 2- Methyl-5-hydroxymethylimidazole, 2-pheyl-4-benzyl-5-hydroxymethylimidazole, 4,4'-methylene-bis- Amino-2-methylimidazole, 1-cyanoethyl-2-phenyl-4,5-di (cyanoethoxymethyl) imidazole, 1-dodecyl- -Benzylimidazolinium chloride, imidazole-containing polyamides, or mixtures thereof. In addition, tertiary amines, organometallic compounds, organic phosphorus compounds, boron compounds, and the like can be further used.

The content of the curing accelerator is not particularly limited, but may be in the range of about 0.01 to 10% by weight, preferably about 0.01 to 5% by weight, based on the total weight of the metal ink composition, May be included in the range of about 0.01 to 0.5% by weight. When the content of the curing accelerator falls within the above-mentioned range, curing of the ink composition can be carried out at a low temperature in a short time, and the safety stability of the ink composition is good.

On the other hand, the low viscosity metal ink composition of the present invention can be produced through various methods.

According to an example of the present invention, metal nanoparticles capped by a C ₁ -C ₂₀ carboxylate-based ligand and a C ₅ -C ₂₀ primary amine-based ligand, a nonpolar organic solvent, a phenoxy resin and an epoxy resin A binder resin, a curing agent, a mixed ether organic solvent, and a dispersing agent, which are dispersed in a solvent, and then dispersed. However, when the metal nanoparticles are dried in the preparation of the composition, aggregation between the particles may occur and dispersion stability may be deteriorated, so that it is difficult to increase the concentration of the metal nanoparticles. Therefore, - It is preferred that they are mixed in a dried state.

The metal ink composition of the present invention described above is applied to a polyimide film through a roll-to-roll coating process such as microgravure coating and slot die coating and then thermally cured to form a seed layer having excellent heat-resistant adhesion to a polyimide film Can be formed.

Such a low viscosity metal ink composition can be fired at a low temperature. Accordingly, the metal ink composition can be applied to various substrates, but preferably the metal ink composition is applied to a polyimide (PI) substrate material to produce a flexible metal foil laminate.

The viscosity of the metal ink composition may be controlled depending on the type of the epoxy resin and the phenoxy resin, the amount of the nonpolar organic solvent and the ether solvent, and may be, for example, about 5 to 500 cps. According to one example, when the metal ink composition is coated on a polyimide film through a roll-to-roll coating such as a microgravure coating, the viscosity of the composition is adjusted to about 5 to 15 cps to yield hundreds of nano, preferably 100 A seed layer having a thickness of ~ 900 nm, more preferably 500-600 nm, may be formed.

<Laminated Sheet>

On the other hand, the present invention provides a laminated sheet comprising a seed layer formed from the low viscosity metal ink composition described above.

According to one example, as shown in Fig. 1, the laminated sheet 10 includes a polyimide film 11; And a seed layer 12 formed on one side of the polyimide film. Alternatively, the seed layer may be formed on the other surface of the polyimide film (not shown).

The seed layer 12 is a layer formed of the low viscosity metal ink composition. The seed layer 12 has excellent heat-resistant adhesion with a polyimide film, and is excellent in heat resistance, chemical resistance, corrosion resistance, adhesion reliability, and bendability. Since the heat-resistant adhesion between the polyimide film and the metal foil can be improved by the seed layer 12, a printed circuit board on which a micro-circuit pattern is implemented can be manufactured.

Specifically, the metal ink composition coated on the polyimide film is melted and secondarily recombined between the metal nanoparticles upon thermal curing, and at the same time, due to the curing of the two or more binder resins containing the epoxy resin and the phenoxy resin, the polyimide film and the plated layer And a seed layer excellent in heat-resistant adhesion can be realized. Particularly, when a novolak epoxy resin excellent in heat resistance, chemical resistance, impact resistance and abrasion resistance is used together with a phenoxy resin, two or more kinds of binder resins can form a seed layer excellent in dimensional stability at a water absorption rate of 0.2%. Such a seed layer maintains a high adhesion with the polyimide film and maintains an excellent adhesion with the circuit layer even though it is subjected to a plating process for forming a metal foil and a heat treatment process for realizing adhesion force. Thus, since the circuit layer can be firmly adhered to the polyimide film of the printed circuit board through the seed layer, a microcircuit pattern can be realized.

The thickness of the seed layer 12 is not particularly limited. When the thickness of the seed layer 12 is about 500 nm to 1 탆, preferably 500 to 600 nm, an undercut occurs due to a difference in etching rate between the seed layer and the copper layer formed thereon Can be prevented.

The resistivity of the seed layer is lowered as the thermosetting temperature of the low viscosity metal ink composition is increased. Especially, when the thermosetting temperature is 200 to 250 占 폚, the specific resistance is very low, about 3.3 占^10-5 to 8.0 占^10-4 ? 占 ㎝ m. Since the resistivity of the seed layer is low, an electrolytic metal foil having a uniform thickness can be formed on the seed layer by electrolytic plating during the production of the flexible metal foil laminate.

In addition, the seed layer may have an adhesion to polyimide film of 5B or more in a cross-cut test according to ASTM D 3359. Further, when an electrolytic metal foil (for example, electrolytic copper foil) is formed on the seed layer, the adhesion strength of the metal foil is as high as about 0.8 to 1.0 kgf / cm in the adhesion test according to IPC-TM 650 2.4.9.

The method for producing the laminated sheet is as follows, but is not limited thereto.

According to one example, the method for producing a laminated sheet includes the steps of applying the low viscosity metal ink composition to one side or both sides of a polyimide film ('S10'); And thermally curing the applied low viscosity metal ink composition to form a seed layer ('S20').

The above S10 may be performed by a roll-to-roll coating method known in the art. Examples of the coating method include, but are not limited to, microgravure coating, slot die coating, gravure coating, and curtain coating.

The S20 is heated at a constant rate from room temperature to a thermosetting temperature to thermally cure the applied low viscosity metal ink composition for a predetermined time.

The heat curing temperature is not particularly limited. However, unless secondary recombination between metal nanoparticles occurs during thermal curing of the metal ink composition, the contact area of the metal nanoparticles with the polyimide film becomes small due to the high specific surface area of the metal nanoparticles, Can be degraded. In addition, if the curing temperature of the composition is too low, some of the organic solvent in the composition may remain in the seed layer, which may lower the adhesive strength of the seed layer, and may cause thermal compression and reflow The organic solvent remaining in the seed layer may be discharged during the process to cause peeling between the substrate and the seed layer or between the seed layer and the plating layer. Therefore, it is preferable that the thermal curing temperature is adjusted in consideration of the curing temperature of the binder resin, the temperature range at which the metal nanoparticles are melted and the second recombination occurs, and the boiling point of the organic solvent. For example, when the thermal curing temperature is about 200 to 250 ° C, the organic solvent evaporates and the size of the crystal grains generated due to the melting and secondary recombination of the metal nanoparticles increases, thereby increasing the contact area with the polyimide film , The binder resin can be cured to further improve the adhesion characteristics between the polyimide film and the seed layer (in particular, metal nanoparticles).

When the rate of temperature rise during the thermal curing of the low viscosity metal ink composition is too high, the solvent of the low viscosity metal ink composition such as a nonpolar organic solvent or a mixed ether solvent is evaporated and removed, A space may be formed and the thickness of the seed layer may not be uniform or the adhesion of a part may be deteriorated. Therefore, it is preferable to adjust the rate of temperature rise to within the range of about 1 to 5 占 폚 / mim.

The thermosetting time is not particularly limited. However, if the thermosetting is performed in a too short time, the solvent of the low viscosity metal ink composition can not be properly removed and may remain in the seed layer. In this case, The solvent remaining in the layer may escape and the circuit layer may peel off. Therefore, when the thermal curing temperature is 200 to 250 ° C, it is preferable to adjust the thermal curing time to 30 minutes to 60 minutes.

&Lt; Flexible metal foil laminates and printed circuit boards &

The present invention provides a flexible metal foil laminate including a seed layer formed of the above-mentioned low viscosity metal ink composition. When a printed circuit board is manufactured using such a flexible metal foil laminates, the adhesion strength between the polyimide film and the plated layer is improved by the seed layer, so that a microcircuit pattern can be realized.

2 and 3 are sectional views showing a flexible metal foil laminate according to the present invention.

According to one example, the metal-clad laminate 20 comprises a polyimide film 21; A seed layer (22) formed on one surface of the polyimide film and formed of the low viscosity metal ink composition; And a plating layer 23 formed on the opposite surface of the seed layer surface in contact with the polyimide film (see FIG. 2).

According to another example, as shown in FIG. 3, the metal foil laminates 20 include a polyimide film 21; A seed layer 22 formed on both sides of the polyimide film, the seed layer 22 being formed of the low viscosity metal ink composition; And a plating layer (23) formed on the opposite surface of the seed layer surface in contact with the polyimide film, respectively.

The seed layer 22 and the method of forming it are the same as those described in the above-mentioned laminated sheet.

Non-limiting examples of the metal forming the plating layer 23 include copper, gold, silver, tin, and nickel, among which copper is preferable.

The thickness of the plating layer is not particularly limited, but when the thickness is about 5 to 9 탆, a fine pattern can be realized in the production of a printed circuit board.

Examples of the method for forming the plating layer include an electrolytic plating method, electroless plating, and the like, but are not limited thereto.

On the other hand, the present invention provides a printed circuit board, preferably a flexible printed circuit board, comprising a seed layer formed from the low viscosity metal ink composition described above. In manufacturing such a printed circuit board, under-cutting can be minimized due to the seed layer during etching, and even if an etching process, a thermocompression bonding process, a reflow process or the like is performed, the polyimide film (Substrate) and the circuit layer is maintained and a fine circuit pattern can be realized.

Hereinafter, the present invention will be described in more detail by way of Examples, Comparative Examples and Experimental Examples. However, the following Examples, Comparative Examples and Experimental Examples are for illustrating the present invention, and the scope of the present invention is not limited thereto.

[Example 1]

1-1. Manufacture of metal nanoparticles

The first solution was prepared by dissolving decanoic acid (139.6 g, 0.5 mol) in methanol (500 ml) in a 1000 ml beaker equipped with a stirrer, and then sodium hydroxide (20 g, 0.5 mol) was dissolved in purified water (500 ml) A second solution was prepared. Meanwhile, silver nitrate (84.9 g, 0.5 mol) was dissolved in purified water (500 ml) to a 2000 ml beaker equipped with a stirrer to prepare a third solution. Thereafter, the second solution was mixed with the prepared first solution, followed by stirring for 30 minutes to form sodium decanoate. Next, the third solution was slowly added dropwise to the formed sodium decanoate to obtain a precipitate, which was a white precipitate, decanoic acid. Thereafter, the present tan liquid was subjected to reduced pressure and filtration while being firstly washed with purified water, followed by vacuum washing and secondary filtration with methanol, followed by drying in a convection oven at 40 to 50 ° C to obtain white decanoic acid silver.

Then, oleoylamine (153.6 g, 574.24 mmol) was added to the obtained decanoic acid (40 g, 143.31 mmol) in a double jacketed reactor maintained at 55 ° C, and the mixture was stirred for 1 to 2 hours. Dissociated. To the dissociated solution, 1-amino-4-methylpiperazine (12.32 g, 106.8 mmol), which is a reducing agent, was slowly added dropwise while stirring for 3 hours and then 50 parts by weight or more of methanol (based on 100 parts by weight of the nanoparticle composition) Followed by centrifugation to obtain metal nanoparticles.

The obtained metal nanoparticles were silver nanoparticles capped with an octanoate ligand and an oleylamine ligand, and the size (diameter) thereof was about 3 to 3.5 nm.

1-2. Preparation of low viscosity ink composition

1 wt% of silver nanoparticles prepared in Example 1-1, 30 wt% of 2-ethyl-1-hexanol as a non-polar organic solvent, and 1 wt% of a bisphenol A epoxy resin (EPIKOTE1009, 1% by weight of a phenoxy resin (PKHH <standard grade> (number average molecular weight: 13,000, weight average molecular weight: 52,000) manufactured by InChem Investment in Chemicals), an acid anhydride compound (HNA- 0.2 wt% of an imidazole compound (2pz, 10% in MCS) as a curing accelerator, 23.5 wt% of a mixed ether solvent (weight ratio of methoxybenzene: diethylene glycol monobutyl ether acetate = 7: 3) And 3% by weight of a phosphate ester compound (BYK-111 from BYK) as a dispersant were mixed by a homomixer and then mixed and dispersed by ball milling to obtain a low viscosity metal ink composition &Lt; / RTI &gt;

1-3. Production of laminated sheet

The low viscosity metal ink composition of Example 1-2 was coated on one side of the polyimide film through the microgravure coating method under the following coating conditions, and then the temperature was raised from room temperature (RT) to 200 DEG C (temperature raising rate: 3 DEG C / min) Treated at a curing temperature of 200 캜 to form a seed layer on the polyimide film to obtain a laminated sheet.

** Coating conditions **

- Coater: Micro-Gravure

- Gravure Roll No .: H07

- Line Speed: 0.5 m / min

- Roll Speed: 80%

1-4. Fabrication of Flexible Copper Clad Laminate

The surface of the seed layer of the laminated sheet prepared in Example 1-3 was plated with a thickness of 9 탆 by an electroplating method to form a copper plating layer on the seed layer. The plating solution used at this time and plating conditions are shown in Table 1. Thereafter, an annealing process (heating from 180 ° C to 180 ° C for 30 minutes, cooling to room temperature) was carried out.

FIG. 4 is a cross-sectional view of the flexible copper clad laminate produced in the above. As can be seen from Fig. 4, a seed layer (Ag) having a thickness of 500 to 600 nm and a copper plating layer having a thickness of 9 mu m were sequentially formed on the polyimide film.

Plating solution H ₂ SO ₄ (98%) 190 g / L CuSO ₄ 75 g / L Polish
(Mectex Inc., 125 J) Brightener 1.5 to 2.0 ml / L Leveler 22 to 23 ml / L Time (min) 48 Temperature (℃) 22-24 Current density 1.5 ADS Thickness (㎛) 9

1-5. Manufacture of printed circuit boards

An acid resistant tape was uniformly adhered to the flexible copper clad laminate produced in Example 1-4 at a width of 5 mm or a width of 10 mm and then subjected to an etching process to form a metal circuit pattern. At this time, distilled water (a), hydrochloric acid (b) and hydrogen peroxide (c) were mixed in a volume ratio of a: b: c = 3: 2: 1.

Subsequently, the substrate on which the metal circuit pattern was formed was subjected to a hot press process four times. Thereafter, as shown in Fig. 5, a reflow process was performed on the thermocompressed substrate to produce a final printed circuit board.

[Example 2]

(Manufactured by InChem Investment in Chemicals) instead of 1% by weight of the phenoxy resin (PKHH <Standard Grade> (number average molecular weight: 13,000, weight average molecular weight: 52,000) A low viscosity metal ink composition, a laminated sheet, and a flexible (nonwoven fabric) sheet were prepared in the same manner as in Example 1, except that 1 wt% of PKHB (number average molecular weight: 9,500, weight average molecular weight: 32,000) A copper clad laminate and a printed circuit board were manufactured.

[Example 3]

(Manufactured by InChem Investment in Chemicals) instead of 1% by weight of the phenoxy resin (PKHH <Standard Grade> (number average molecular weight: 13,000, weight average molecular weight: 52,000) A low-viscosity metal ink composition, a laminated sheet, and a flexible (low molecular weight) ink composition were prepared in the same manner as in Example 1 except that 1 wt% of PKHC (low molecular weight) (number average molecular weight: 11,000, weight average molecular weight: 43,000) A copper clad laminate and a printed circuit board were manufactured.

[Example 4]

A low viscosity metal ink composition, a laminated sheet, and a flexible copper clad laminate were produced in the same manner as in Example 1, except that the laminated sheet of Example 1-3 was heat-treated at a curing temperature of 250 ° C instead of the curing temperature of 200 ° C. And a printed circuit board were manufactured.

[Example 5]

A low viscosity metal ink composition, a laminated sheet, a flexible copper clad laminate and a printed circuit board were prepared in the same manner as in Example 2 except that the heat treatment was performed at a curing temperature of 250 ° C instead of the curing temperature of 200 ° C in Example 2 .

[Example 6]

A low viscosity metal ink composition, a laminated sheet, a flexible copper clad laminate and a printed circuit board were prepared in the same manner as in Example 3, except that the heat treatment was performed at a curing temperature of 250 ° C instead of the curing temperature of 200 ° C .

[Example 7]

1% by weight of the bisphenol A-based epoxy resin (EPIKOTE1009 from Hecion Corporation, equivalent weight: 1000) used in Example 1-2 and phenoxy resin (PKHH <Standard Grade> (number average molecular weight: 13,000 , 1 weight% of bisphenol A epoxy resin (EPIKOTE1009, equivalent weight: 1000 by Hecion Corp.), O-Cresol Nonolac Epoxy (YDCN500-90P of Kukdo Chemical Co., And 0.5 wt% of a phenoxy resin (PKHH <Standard Grade> (number average molecular weight: 13,000, weight average molecular weight: 52,000) manufactured by InChem Investment in Chemicals) , A low viscosity metal ink composition, a laminated sheet, a flexible copper clad laminate and a printed circuit board were prepared in the same manner as in Example 1, except that the heat treatment was performed at a curing temperature of 250 캜 instead of the curing temperature of 200 캜.

[Example 8]

1% by weight of the bisphenol A-based epoxy resin (EPIKOTE1009 from Hecion Corporation, equivalent weight: 1000) used in Example 1-2 and phenoxy resin (PKHH <Standard Grade> (number average molecular weight: 13,000 , 1 weight% of bisphenol A epoxy resin (EPIKOTE1009, equivalent weight: 1000 by Hecion Corp.), O-Cresol Nonolac Epoxy (YDCN500-90P of Kukdo Chemical Co., And 0.5 wt% of a phenoxy resin (PKHB <ultra low molecular weight> (InChem Investment in Chemicals) (number average molecular weight: 9,500, weight average molecular weight: 32,000) , A low viscosity metal ink composition, a laminated sheet, a flexible copper clad laminate and a printed circuit board were prepared in the same manner as in Example 1, except that the heat treatment was performed at a curing temperature of 250 캜 instead of the curing temperature of 200 캜.

[Example 9]

1% by weight of the bisphenol A-based epoxy resin (EPIKOTE1009 from Hecion Corporation, equivalent weight: 1000) used in Example 1-2 and phenoxy resin (PKHH <Standard Grade> (number average molecular weight: 13,000 , 1 weight% of bisphenol A epoxy resin (EPIKOTE1009, equivalent weight: 1000 by Hecion Corp.), O-Cresol Nonolac Epoxy (YDCN500-90P of Kukdo Chemical Co., And 0.5 wt% of a phenoxy resin (PKHC <low molecular weight> (InChem Investment in Chemicals) (number average molecular weight: 11,000, weight average molecular weight: 43,000) , A low viscosity metal ink composition, a laminated sheet, a flexible copper clad laminate and a printed circuit board were prepared in the same manner as in Example 1, except that the heat treatment was performed at a curing temperature of 250 캜 instead of the curing temperature of 200 캜.

[Comparative Example 1]

1% by weight of the bisphenol A-based epoxy resin (EPIKOTE1009 from Hecion Corporation, equivalent weight: 1000) used in Example 1-2 and phenoxy resin (PKHH <Standard Grade> (number average molecular weight: 13,000 , Weight average molecular weight: 52,000) was used instead of 2 wt% of bisphenol A-based epoxy resin (EPIKOTE1009 from Hecion Corp., equivalent weight: 1000) To obtain an ink composition.

[Comparative Example 2]

1% by weight of the bisphenol A-based epoxy resin (EPIKOTE1009 from Hecion Corporation, equivalent weight: 1000) used in Example 1-2 and phenoxy resin (PKHH <Standard Grade> (number average molecular weight: 13,000 Except that 2 weight% of phenoxy resin (PKHH <standard grade> (number average molecular weight: 13,000, weight average molecular weight: 52,000) of InChem Investment in Chemicals Co., Ltd. was used instead of 1 weight% Was performed in the same manner as in Example 1 to obtain a low viscosity metal ink composition.

[Comparative Example 3]

1% by weight of the bisphenol A-based epoxy resin (EPIKOTE1009 from Hecion Corporation, equivalent weight: 1000) used in Example 1-2 and phenoxy resin (PKHH <Standard Grade> (number average molecular weight: 13,000 Except that 2 wt% of a phenoxy resin (PKHB <ultra low molecular weight> (InChem Investment in Chemicals Co., Ltd.) (number average molecular weight: 9,500, weight average molecular weight: 32,000) was used instead of 1 wt% Was performed in the same manner as in Example 1 to obtain a low viscosity metal ink composition.

[Comparative Example 4]

1% by weight of the bisphenol A-based epoxy resin (EPIKOTE1009 from Hecion Corporation, equivalent weight: 1000) used in Example 1-2 and phenoxy resin (PKHH <Standard Grade> (number average molecular weight: 13,000 Except that 2 wt% of phenoxy resin (PKHC <low molecular weight> (InChem Investment in Chemicals, Inc.) (number average molecular weight: 11,000, weight average molecular weight: 43,000) was used instead of 1 wt% Was performed in the same manner as in Example 1 to obtain a low viscosity metal ink composition.

[Comparative Example 5]

A low viscosity metal ink composition, a laminated sheet, a flexible copper clad laminate and a printed circuit board were produced in the same manner as in Comparative Example 1, except that the heat treatment was performed at a curing temperature of 250 캜 instead of the curing temperature of 200 캜 .

[Comparative Example 6]

A low viscosity metal ink composition, a laminated sheet, a flexible copper clad laminate and a printed circuit board were produced in the same manner as in Comparative Example 2 except that the heat treatment was performed at a curing temperature of 250 캜 instead of the curing temperature of 200 캜 in Comparative Example 2 .

[Comparative Example 7]

A low viscosity metal ink composition, a laminated sheet, a flexible copper clad laminate and a printed circuit board were produced in the same manner as in Comparative Example 3 except that the heat treatment was performed at a curing temperature of 250 캜 instead of the curing temperature of 200 캜 in Comparative Example 3 .

[Comparative Example 8]

A low-viscosity metal ink composition, a laminated sheet, a flexible copper clad laminate and a printed circuit board were produced in the same manner as in Comparative Example 4, except that the heat treatment was performed at a curing temperature of 250 ° C instead of the curing temperature of 200 ° C .

[Comparative Example 9]

1% by weight of the bisphenol A-based epoxy resin (EPIKOTE1009 from Hecion Corporation, equivalent weight: 1000) used in Example 1-2 and phenoxy resin (PKHH <Standard Grade> (number average molecular weight: 13,000 1 weight% of a bisphenol A epoxy resin (EPIKOTE1009, equivalent weight: 1000, manufactured by Hecion Corp.) and 0-Cresol Nonolac Epoxy (YDCN500-90P, available from Kukdo Chemical Co., Ltd., equivalent weight: 206) Except that the heat treatment was performed at a curing temperature of 250 占 폚 in place of the curing temperature of 200 占 폚 in the production of the laminated sheet of Example 1-3, &Lt; / RTI &gt;

[Experimental Example 1] - Dispersion stability of low viscosity metal ink composition

The dispersion stability of the low viscosity metal ink compositions prepared in Examples 1 to 3 and Comparative Examples 1 to 4 was evaluated as follows. The evaluation results are shown in Table 2 below.

Each metal ink composition was allowed to stand at room temperature for 4 weeks, and the occurrence of precipitates such as metal nanoparticles and epoxy binders was checked to evaluate dispersion stability. At this time, the following evaluation was made according to the generation time of the precipitate.

◎: over 4 weeks,

○: 1 week to less than 4 weeks,

X: Less than one week or if epoxy resin is not usable

Example Comparative Example One 2 3 One 2 3 4 When precipitates occur ◎ ◎ ◎ ◎ ◎ ◎ ◎

As a result of the evaluation, similarly to the low viscosity metal ink compositions of Comparative Examples 1 to 4, the low viscosity metal ink compositions of Examples 1 to 3 did not cause sediment even when stored for a long time. From this, it was confirmed that the low viscosity metal ink composition according to the present invention is excellent in dispersion stability.

[Experimental Example 2] Measurement of adhesion and resistivity of seed layer

The adhesive strength and specific resistance of the seed layer formed from the low viscosity metal ink composition according to the present invention were measured as follows. The measurement results are shown in Tables 3 to 5 below.

(1) Adhesion

The cross-cut tape test was repeated five times according to ASTM D 3359 on the seed layers of the laminated sheets prepared in Examples 1 to 9 and Comparative Examples 1 to 8, respectively, to evaluate the adhesive strength.

(2) Resistivity

The sheet resistance (Ω / cm ² ) of the laminated sheet prepared in each of Examples 1 to 9 and Comparative Examples 1 to 8 was measured using a 4-point probe type surface resistance meter, and then SEM and FIB analysis (㎝ · cm) was calculated according to the following equation (1).

Example Comparative Example One 2 3 One 2 3 4 Thermal curing temperature:
200 ℃ Adhesion 5B 5B 5B 4B 5B 5B 5B Resistivity 7.7 × 10 ^-4 7.7 × 10 ^-4 8.0 × 10 ^-4 7.6 × 10 ^-4 8.1 × 10 ^-4 7.8 × 10 ^-4 8.4 × 10 ^-4

Example Comparative Example 4 5 6 5 6 7 8 Thermal curing temperature:
250 ℃ Adhesion 5B 5B 5B 4B 5B 5B 5B Resistivity 3.8 × 10 ^-5 3.3 x 10 ^-5 3.8 × 10 ^-5 3.2 x 10 ^-5 4.2 × 10 ^-5 3.9 x 10 ^-5 4.3 × 10 ^-5

Example 7 Example 8 Example 9 Comparative Example 9 Thermal curing temperature:
250 ℃ Adhesion 5B 5B 5B 5B Resistivity 3.9 x 10 ^-5 3.9 x 10 ^-5 3.7 x 10 ^-5 4.0 × 10 ^-5

As a result of the measurement, the adhesive strength of the seed layer (mixed use of epoxy resin and phenoxy resin) of Examples 1 to 9 was 5B, which was higher than that of the seed layer of Comparative Examples 1 and 5 (using epoxy resin). In addition, the seed layers of Examples 1 to 9 had lower resistivity than the seed layers of Comparative Examples 2 to 4 and 6 to 8 (using phenoxy resin). From this, it can be seen that the low-viscosity metal ink composition according to the present invention can form a seed layer having a high adhesive force and a low specific resistance, so that a plating layer having excellent adhesion strength with a uniform thickness can be formed later.

In addition, although the resistances of Examples 4 to 6 were lower than those of Examples 1 to 3, the adhesive strength did not decrease. From this, it was confirmed that when the seed layer is formed using the low viscosity metal ink composition according to the present invention, the resistivity is lowered without decreasing the adhesive force as the thermal curing temperature of the low viscosity metal ink composition is increased.

[Experimental Example 3] - Measurement of adhesive force of printed circuit board circuit layer

The adhesion of the printed circuit board to the circuit layer using the low viscosity metal ink composition according to the present invention was measured as follows. The measurement results are shown in Table 6 below.

The printed circuit boards prepared in Examples 1 to 9 and Comparative Example 9 were each cut into a size of 100 mm X 5 mm (10 mm), and then the polyimide film (IPC-TM 650) And the adhesive strength was measured at an angle of 90 [deg.].

Example 7 Example 8 Example 9 Comparative Example 9 Adhesion (kgf / cm)
(Heat curing temperature: 250 占 폚) 0.9-1.1 0.85 to 1.0 0.85-0.95 0.7 to 0.8

As a result of the test, the circuit layers of Examples 7 to 9 had higher bonding strength than the circuit layers of Comparative Example 9. [ From this, it was found that when the seed layer is formed using the low viscosity metal ink composition according to the present invention, the adhesion between the seed layer and the plating layer is high, so that the peeling phenomenon of the plating layer can be prevented.

10: laminated sheet,
11: polyimide film, 12: seed layer,
20: Flexible metal foil laminates,
21: polyimide film, 22: seed layer,
23: Plating layer

Claims (13)

(a) metal nanoparticles capped by a C ₁ -C ₂₀ carboxylate-based ligand and a C ₁ -C ₂₀ primary amine-based ligand;
(b) two or more kinds of binder resins including an epoxy resin and a phenoxy resin;
(c) a nonpolar organic solvent;
(d) a mixed ether solvent containing an aromatic ether solvent and an aliphatic ether solvent;
(e) a curing agent; And
(f) Dispersant
Wherein the low viscosity metal ink composition is a low viscosity ink. The method of claim 1, wherein the metal nanoparticles (a)
A metal core, a C ₁ to C ₂₀ carboxylate-based ligand, and a C ₅ to C ₂₀ primary amine-based ligand,
Wherein the C ₁ -C ₂₀ carboxylate-based ligand and the C ₅ -C ₂₀ primary amine-based ligand are bonded or adsorbed on the surface of the metal core, respectively. The method according to claim 1,
Wherein the metal nanoparticles (a) are nanoparticles of a metal selected from the group consisting of gold, silver, copper, nickel, platinum, cobalt, palladium and alloys thereof. The method according to claim 1,
Wherein the metal nanoparticles (a) have an average particle diameter of 1 to 20 nm. The method according to claim 1,
Wherein the content of the metal nanoparticles (a) is 30 to 80% by weight based on the total weight of the metal ink composition. The method of claim 1, wherein the metal nanoparticles (a)
A carboxylic acid or its salt of C ₁ ~ C ₂₀ reacted with a metal salt to form a metal carboxylate of a C ₁ ~ C _20;
A metal carboxylate of a C ₁ ~ C _20, to form a metal carboxylate complex of C ₅ ~ C ₂₀ with C ₁ ~ C ₂₀ The primary amine of the C ₅ ~ C ₂₀ bond is reacted with a primary amine of ; And
Forming a metal nanoparticle by adding a reducing agent to the C ₁ -C ₂₀ metal carboxylate complex to which the C ₅ -C ₂₀ primary amine is bonded
&Lt; / RTI &gt; wherein the low viscosity ink composition is produced through a process comprising the steps of: The method according to claim 1,
Based on 100 parts by weight of the metal nanoparticles
The content of the epoxy resin is 1 to 4 parts by weight,
Wherein the content of the phenoxy resin is 0.5 to 3 parts by weight. The method according to claim 1,
Wherein the non-polar organic solvent (c) is at least one selected from the group consisting of a C ₅ to C ₂₀ hydrocarbon solvent and a C ₆ to C ₁₅ alcohol solvent. The method according to claim 1,
Wherein the non-polar organic solvent (c) and the mixed ether solvent (d) are contained in a weight ratio of 30 to 70:70 to 30. The method according to claim 1,
Wherein the aromatic ether solvent is an aromatic ether solvent containing a C ₁ -C ₆ alkoxy group,
Wherein the aliphatic ether-based solvent is an aliphatic ether-based solvent containing a C ₁ -C ₆ alkoxy group. Polyimide films; And
A seed layer formed from the low viscosity metal ink composition according to any one of claims 1 to 10 on one surface or both surfaces of the polyimide film
. Polyimide films;
A seed layer formed from the low viscosity metal ink composition according to any one of claims 1 to 10 on one side or both sides of the polyimide film; And
A plating layer formed on an opposite surface of the seed layer surface in contact with the polyimide film;
And a flexible metal foil laminate. A printed circuit board comprising a seed layer formed from the low viscosity metal ink composition according to any one of claims 1 to 10.

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