KR20170048714A - Ink composition for light sintering and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a light sintering ink composition and a method for producing the same. The light sintering ink composition comprises: a metal nano-particle satisfying equation 1, A_1/A_2 <= 0.2; a low melting point metal having a melting point of 800C or lower; a non-aqueous organic binder; and a non-aqueous solvent. In the equation 1, A_1/A_2 is a ratio obtained by dividing a metal 2p_3_(/2) peak area (A_1) of an oxide of a metal by a metal 2p_3_(/2) peak area (A_2) of a metal on an X-ray photoelectron spectroscopic spectrum with respect to the surface of a metal nano-particle.

Description

TECHNICAL FIELD The present invention relates to an ink composition for light sintering,

The present invention relates to an ink composition for photo-sintering, and particularly relates to an ink composition for photo-sintering which is capable of producing a conductive thin film having excellent electrical conductivity and excellent adhesion to a substrate by sintering ability even when irradiated with extremely low intensity light. An ink composition and a process for producing the same.

Research on manufacturing electronic components and energy application parts using various printing processes based on inks and pastes containing metal nanoparticles is one of the megatrends of current technology development.

The ink containing the metal nanoparticles can be printed on various substrates through a single printing process such as screen printing, inkjet printing, gravure offset printing and reverse offset printing, without using a complicated process of photolithography Thereby simplifying the process. In addition, the manufacturing cost can be drastically reduced due to the simplification of the process, and the wiring width can be miniaturized, making it possible to manufacture a highly integrated and highly efficient printed circuit.

The Applicant has noticed that the conductivity of a metal wiring is deteriorated by a surface oxide film existing in metal nanoparticles in a metal nanoparticle-based ink, thereby providing a method of synthesizing metal nanoparticles in which formation of a surface oxide film is completely controlled Korean Patent Publication No. 10-2013-0111180). However, in Korean Patent Laid-Open No. 10-2013-0111180 filed by the present applicant, the ink containing the metal oxide nanoparticles controlled by the surface oxide film is applied to thermo-plasticize, and in order to impart bulk characteristics through such thermo-plasticization Temperature treatment in an inert atmosphere at a high temperature of 300 ° C or higher for a long period of time of up to 2 hours. Such a high-temperature heat treatment for a long time makes it difficult to utilize a flexible polymer substrate that is spotlighted as a substrate of a flexible element, and further, it is disadvantageous in a roll-to-roll continuous process having excellent commercial properties.

In particular, an ink composition containing copper nanoparticles or nickel nanoparticles has a disadvantage in that it has a high melting point of 1000 ° C or higher, and therefore has a disadvantage in that it must apply a high energy when producing conductive thin films using the nanoparticles.

Korean Patent Publication No. 10-2013-0111180

Disclosure of the Invention In order to solve the above problems, the present invention provides an ink composition for photo-sintering capable of producing a conductive thin film having excellent electrical conductivity and excellent adhesion to a substrate by sintering at a very low intensity, And a method for producing the same.

The present invention relates to metal nanoparticles satisfying the following relational expression 1: A low melting point metal having a melting point of 800 DEG C or less; Non-aqueous organic binders; And a non-aqueous solvent.

In another aspect of the present invention, there is provided a method for preparing a metal nanoparticle comprising: a) heating and stirring a first solution containing a metal precursor, an organic acid, an amine compound and a reducing agent to form a metal nanoparticle Synthesizing; b) dispersing the metal nanoparticles, the low-melting metal having a melting point of 800 ° C or lower, and the non-aqueous organic binder in a non-aqueous solvent.

Further, another embodiment of the present invention is a metal nanoparticle comprising: A) metal nanoparticles satisfying the following relational expression 1; A low melting point metal having a melting point of 800 DEG C or less; Non-aqueous organic binders; And a non-aqueous solvent; B) applying the ink composition for photo-sintering to a transparent polymer substrate to form a coating film; And C) irradiating the coating film with light so as to satisfy the following relational expression 2 to produce a conductive thin film.

[Relation 1]

A ₁ / A ₂ ? 0.2

[Relation 2]

I _LS ≤ I _c

(In the equation _1, A 1 / A ₂ is an X- ray photoelectron spectroscopy spectrum phase, the metal of the metal oxide 2p _3/2 peak area (A ₁₎ on the surface of the metal nanoparticles, the metal of the metal 2p _{3 / 2} peak area (A &lt; ₂ &gt;),

In the relational expression 2, I _LS is the energy (J / cm 2) of the light irradiated to the coating film, and I _c is the maximum energy (J / cm 2) of the light in which the transparent polymer substrate is not deteriorated.

The ink composition for photo-sintering and the method of manufacturing the same according to the present invention may have the following advantages in the production of the conductive thin film.

First, light-sintering through an extremely low light energy that does not deteriorate a low-cost transparent polymer substrate can be performed, so that a conductive metal thin film having extremely excellent electrical conductivity comparable to a bulk and having an extremely excellent adhesive force with a substrate can be manufactured.

Second, since the conductive thin film can be manufactured by a light sintering process which is excellent in thermal stability, it is possible to prevent the substrate from being damaged even if the substrate has a low upper limit temperature.

Third, the roll-to-roll process can be implemented, which makes it possible to simplify the process and reduce manufacturing costs.

1 is a transmission electron microscope (SEM) image of copper nanoparticles prepared according to an embodiment of the present invention,
FIG. 2 is an X-ray photoelectron spectroscopy spectrum of copper nanoparticles prepared according to an example of the present invention,
3 is an electron micrograph of core-shell alloy nanoparticles prepared according to Production Example 2 of one example of the present invention,
4 is a transmission electron microscope (SEM) image of core-shell alloy nanoparticles prepared according to Preparation Example 2 of the present invention,
5 is an X-ray diffraction pattern of core-shell alloy nanoparticles prepared according to Production Example 2 of one example of the present invention,
FIG. 6 is a graph showing changes in resistance of the conductive thin film produced according to Example 1, Example 2, and Comparative Example 1. FIG.

Hereinafter, the ink composition for photo-sintering of the present invention and the method for producing the same will be described in detail with reference to the accompanying drawings. The following drawings are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. Therefore, the present invention is not limited to the following drawings, but may be embodied in other forms, and the following drawings may be exaggerated in order to clarify the spirit of the present invention. Hereinafter, the technical and scientific terms used herein will be understood by those skilled in the art without departing from the scope of the present invention. Descriptions of known functions and configurations that may be unnecessarily blurred are omitted.

As a result of deepening the study on metal nanoparticles controlled in the formation of the surface oxide film proposed in Japanese Patent Application Laid-Open No. 10-2013-0111180, the present applicant has found that metal nanoparticles having a surface oxide film formation- It has been found that, when photo-sintering an ink composition containing a melting point metal, a metal thin film having electric conductivity comparable to that of a bulk can be produced with surprisingly low light energy, and surprisingly, the conventional metal nano- It is possible to produce a conductive metal thin film having an adhesion with an extremely excellent substrate that can not be obtained at the time of using light sintering. Thus, the present invention has been accomplished.

In detail, the ink composition for photo-sintering according to an embodiment of the present invention includes metal nanoparticles satisfying the following relational expression 1; A low melting point metal having a melting point of 800 DEG C or less; Non-aqueous organic binders; And a non-aqueous solvent.

[Relation 1]

A ₁ / A ₂ ? 0.2

In equation _1, A 1 / A ₂ is a metal of the X- ray photoelectron spectroscopy spectrum phase, a metal oxide on the surface of the metal nanoparticles 2p _3/2 The peak area of metal to _{metal, (A 1) 2p 3/} 2 And the peak area (A ₂ ). Specifically, X-ray photoelectron spectra were measured using an Al Kα source at a vacuum degree of 10 ^-8 or less, and the metal 2p _3/2 peaks of metal and metal oxides were extracted and the degree of oxidation Can be calculated.

In the metal nanoparticles, the surface oxide film formation may preferably be substantially completely prevented. Specifically, the metal nanoparticles according to an embodiment of the present invention may be that metal 2p _3/2 peak of the oxide of the metal does not appear to substantially, so that A ₁ / A ₂ as shown in Figure 2 is substantially To zero. As will be described later, in the manufacturing process of the metal nanoparticles, the surface oxide film formation may be controlled as the metal core of the metal nanoparticles is capped with the capping layer containing the organic acid, and preferably the surface oxide film formation is substantially It may be completely prevented.

The metal nanoparticles according to an exemplary embodiment are not particularly limited as long as they are metals having high electrical conductivity among the metals commonly used for producing the metal thin films. As a specific example, the metal nanoparticles may be any one or two or more selected from copper, silver, gold, nickel, tin, aluminum and alloys thereof, and may be copper. Copper and silver are the next best metals with good electrical conductivity. They have excellent electrical conductivity and are economical because they can easily supply and receive at low prices.

The average diameter of the metal nanoparticles may be from 20 to 300 nm, and more preferably from 50 to 300 nm. In the above range, metal nanoparticles are tightly packed together and can be uniformly sintered without photo-crystallization during photo-sintering. The shape of the metal nanoparticles is not particularly limited, but may be an angular polygonal shape, a columnar shape, a spherical shape, or a shape in which they are mixed.

The low melting point metal in the present invention has a relatively low melting point as compared to the metal nanoparticles, and specifically refers to a metal having a melting point of 800 DEG C or less, more specifically, a melting point of 150 to 800 DEG C, Or more of the above metals. By using the low-melting metal having a melting point of 800 DEG C or less together with the metal nanoparticles, the light-sintering of the ink composition can have an extremely excellent sintering ability even though it is irradiated with extremely low intensity light, It is possible to produce a conductive metal thin film having extremely excellent electrical conductivity comparable to that of a bulk, and having an extremely excellent adhesive strength to a substrate, which is comparable to a bulk.

Specifically, the low melting point metal can be melted more easily than the metal nanoparticles by light irradiation. Due to such characteristics, the flowability of the metal is improved even when irradiated with light of extremely low energy, And the conductive thin film thus prepared can have a very good electric conductivity. In addition, it is possible to prevent the substrate from being damaged in the conductive thin film formation step even if the substrate has an extremely low temperature of 200 ° C. or less, because of its excellent thermal stability due to treatment with extremely low intensity light, There is an advantage that a conductive thin film having electric conductivity can be formed.

The low melting point metal according to an exemplary embodiment of the present invention may have a relatively low melting point as compared to the metal nanoparticles. For example, the low melting point metal may be an alloy composed of two or more metals selected from Cu, Sn, Ag, Bi, Zn, Lt; / RTI &gt; At this time, the kind and content of the low melting point metal can be adjusted in consideration of the physical properties required for the conductive thin film to be produced. Preferably, an alloy containing the same metal as the metal nanoparticles is used as the low melting point metal. In detail, when an alloy containing the same metal as the metal nanoparticles is used as the low melting point metal, the metal nanoparticles and the low melting point metal are more easily fused with each other during the light sintering, It contains the same metal and affects the metal nanoparticles so that sintering is more effective even with lower energy injection.

More specifically, when the metal nanoparticles are copper, the low melting point metal may be a copper-tin alloy. The melting point of copper is about 1,083 DEG C, and when an alloy is produced by mixing tin with copper, an alloy having a melting point significantly lower than that of a copper single metal can be obtained. The melting point of the copper-tin-based alloy depends on how the ratio of the two metals is controlled, and it is preferable to mix copper and tin so as to have a melting point of 800 DEG C or lower.

As a preferred example, the copper-tin-based alloy may be one satisfying the following formula (1).

[Chemical Formula 1]

Cu ₁ Sn _x

(In the formula (1), x is 0.1? X? 2.)

By using a copper-tin-based alloy satisfying the formula (1) as a low-melting-point metal, it is possible to produce a conductive thin film having excellent electrical conductivity by producing a conductive thin film by photo- And may not deteriorate the mechanical properties of the conductive thin film.

The average diameter of the copper-tin-based alloy may be from 5 to 300 nm, and more preferably from 20 to 200 nm. In the above range, the metal nanoparticles and the copper-tin alloy are tightly packed together and can be uniformly sintered without photo-crystallization at the time of photo-sintering with extremely low intensity of light irradiation. The shape of the copper-tin-based alloy is not particularly limited, but may be an angular polygonal shape, a columnar shape, a spherical shape, a core-shell shape, or a mixed shape thereof. The copper-tin-based alloy may be added in an amount of 0.1 to 50 parts by weight based on 100 parts by weight of the metal nanoparticles, but is not limited thereto.

As described later, the low-melting-point metal is also synthesized by the same production method as the metal nanoparticles, and can be capped with a capping layer containing an organic acid, thereby controlling the formation of a surface oxide film, The surface oxide film formation may be substantially completely prevented. Specifically, the low-melting metal can satisfy the following relation 1-1, substantially is A, could result in _S1 / _S2 A is substantially zero in accordance with the 2p _3/2 peak does not appear in the oxide having a low melting point metal.

[Relational expression 1-1]

A _S1 / A _S2 ? 0.2

In equation 1-1, A _S1 / _S2 A is X- ray on the surface of the low-melting metal particles photoelectron spectroscopy spectrum phase, a metal oxide having a low melting point metal 2p _3/2 peak area _(S1 A) a low-melting metal of metal 2p _3/2 is divided by the peak area ratio _(S2 a). More specifically, ^10-8 by using Al Kα source at a vacuum degree of less and measuring the X- ray photoelectron spectrum of the low melting point metals and metal oxides having a low melting point metal 2p _3/2 peak (peak) peak area ratio between the two extracts The degree of oxidation can be calculated. However, the low melting point metal is in accordance with being a two more kinds of mixed metal alloy, a low-melting metal 2p _3/2 The peak area of the oxide of the metal (A _S1) is a metal of each metal contained in the low melting point metal oxide 2p _3/2 can be obtained by adding the peak area, the metal having a low melting point metal 2p _3/2 peak area _(S2 a) can be obtained by adding a metal 2p _3/2 peak area of each of the metal contained in the low melting point metal.

That is, the ink composition for photo-sintering according to an exemplary embodiment of the present invention includes metal nanoparticles satisfying Relational Formula 1; A low melting point metal satisfying the relational expression 1-1 and having a melting point of 800 DEG C or lower; Non-aqueous organic binders; And a non-aqueous solvent.

As described above, the ink composition for photo-sintering according to an embodiment of the present invention includes the metal nano-particles satisfying the relational expression 1 and the low-melting metal satisfying the relational expression 1-1, It is possible to produce a conductive metal thin film having a remarkably excellent sintering ability and having an excellent electrical conductivity and an extremely excellent bonding strength to a substrate.

As described above, the ink composition for photo-sintering according to an exemplary embodiment of the present invention includes metal nanoparticles satisfying the relational expression 1 and a low melting point metal having a melting point of 800 DEG C or lower, so that the polymer binder remains in the metal thin film without being carbonized Light can be sintered through light energy extremely low in strength, so that a conductive metal thin film having extremely excellent electric conductivity comparable to a bulk and having an extremely excellent adhesion to a substrate can be manufactured.

In detail, the ink composition for photo-sintering according to an embodiment of the present invention irradiates light of extremely low energy satisfying the following relational expression 2 to maintain the physical properties of a low-cost transparent polymer substrate, and the photo- Has an electrical conductivity and is advantageous in that it can produce a conductive thin film having remarkable adhesion with a substrate.

[Relation 2]

I _LS ≤ I _c

In the relational expression 2, I _LS is the energy (J / cm 2) of the light irradiated onto the coating film, and I _c is the maximum energy (J / cm 2) of the light in which the transparent polymer substrate is not deteriorated.

Such optical sintering conditions (the condition of relational expression 2) are not known in the field of metal wiring manufacturing methods using conventional light sintering, and under the conditions not studied, metal nanoparticles satisfying Relation 1 and low Is a condition that may be present in the case of photo-sintering an ink composition containing a melting point metal.

That is, the ink composition according to the present invention is manufactured by forming a conductive thin film having improved bonding strength with a substrate by a characteristic configuration in which energy of light sintered so as to have electrical conductivity comparable to that of a bulk is lower than energy of light which does not deteriorate a low- There is a characteristic that can be done.

The light sintering condition of the relational expression 2 is very surprising to those skilled in the field of optical sintering using metal nanoparticles. In general, sintering of metal nanoparticles during light sintering is known to cause the surface area of metal nanoparticles to be instantaneously melted by the high energy applied by light. In order to sinter these metal nanoparticles, Lt; 2 &gt; or more. However, at a high temperature (instantaneous high temperature) condition such that at least the surface area of the metal nanoparticles is instantaneously melted, the inexpensive transparent polymer substrate is inevitably deteriorated. Substantially, inexpensive transparent polymer substrates such as polyethersulfone (PES), polyethylene naphthalate (PEN) or polyethylene terephthalate (PET) are deformed when light having a light quantity of 2 J / cm 2 or more is irradiated. However, when the densification (sintering) mechanism of the surface melting of the metal nanoparticles is taken into account, the low-cost transparent polymer substrate can be made of metal nanoparticles satisfying relational expression 1 and low melting point metal , It means that sintering of the ink composition can be made so as to have electric conductivity comparable to that of the bulk.

As described above, the ink composition according to one example of the present invention can produce a conductive metal thin film in which the polymer binder remains with electrical conductivity comparable to that of the bulk by irradiating light according to relational expression (2).

The ink composition according to an embodiment of the present invention is excellent in thermal stability to such an extent that the polymeric binder mixed with the metal nanoparticles can remain. Therefore, even if the substrate has a very low process upper limit temperature of 200 캜 or less, And the adhesive strength between the metal thin film and the substrate is extremely excellent due to the residual polymer binder, so that it is possible to manufacture a conductive metal thin film suitable for flexible parts. In addition, since a light sintering process can be used, it is possible to manufacture a large area in a very short time in the atmosphere, which is advantageous in optical resolution, and it is possible to realize a roll-to-roll process, There are advantages.

In particular, in the case of an ink composition for photo-sintering comprising copper metal nanoparticles and a copper-tin-based alloy, it can be sintered through light irradiation with extremely low energy of 1.3 J / cm 2 or less, It can have excellent electric conductivity.

In one example, light irradiation can be performed by continuously irradiating light in a wavelength band of 200 to 800 nm. Light in a wavelength band of 200 to 800 nm is a wavelength band including light in a visible light band. Such light of 200 to 800 nm is irradiated to cause light sintering between metal nanoparticles, thereby minimizing thermal damage to the substrate .

More specifically, light irradiation can be performed by continuously irradiating light in a wavelength band of 370 to 800 nm, more specifically, light in a wavelength band of 400 to 800 nm. The irradiation of the light of the wavelength band of 370 to 800 nm, specifically the light of the wavelength band of 400 to 800 nm, means that light is sintered by visible light rather than ultraviolet rays having strong energy.

Light sintering by visible light is a constitution possible by capping with a capping layer containing an organic acid to prevent the formation of a surface oxide film and photo-sintering metal nanoparticles whose surface maintains properties of metals other than oxides. As the light sintering is performed by visible light irradiation, the ultraviolet light irradiation substrate can be remarkably free from thermal damage.

Also, the light irradiation can be performed in which light is continuously irradiated for 1 to 2 msec. That is, according to an embodiment of the present invention, a conductive thin film having excellent electrical conductivity and excellent adhesion to a substrate can be manufactured by irradiating light for an extremely short time of 1 to 2 msec. In order to prevent damages to the substrate and sintering at a minimum temperature as light of high energy is irradiated for sintering the metal nanoparticles during the light sintering of the ink containing the conventional metal nanoparticles, Light is irradiated in a pulse form.

However, according to one embodiment of the present invention, it is not necessary to design a pulse width, a pulse gap, a pulse number, and the like, which should be individually specified for each substrate by the thickness of the metal thin film to be manufactured, (Continuously irradiating light) for a long period of time, so that stable light sintering can be performed.

The time of light irradiation can affect the substantial temperature of the thin film (the film to which the light is irradiated) and the substantial temperature of the substrate during the light sintering process due to the accumulation of heat generated by the light. The irradiation time of the light can be appropriately changed in consideration of the material of the substrate and the like. However, light having a wavelength band of 200 to 800 nm, preferably wavelength of 370 to 800 nm, having an energy of 1.3 J / More preferably, when light in a wavelength band of 400 to 800 nm is continuously irradiated in a time of less than 2 msec, inhomogeneous light sintering may occur and there is a danger that the production of a large-area metal thin film may be difficult, There is a risk that the substrate is damaged by accumulated heat.

In the ink composition according to an exemplary embodiment of the present invention, light having an energy of 1.3 J / cm 2 or less at the time of light irradiation and irradiating light having intensity higher than that at which the metal nanoparticles are sintered may be irradiated to produce a conductive thin film. Specifically, when the amount of light to be irradiated is 0.9 J / cm 2 or more, light sintering of metal nanoparticles may occur.

As described above, the ink composition for photo-sintering according to an embodiment of the present invention includes metal nanoparticles satisfying Relational Formula 1; A low melting point metal having a melting point of 800 DEG C or less; Non-aqueous organic binders; And a non-aqueous solvent.

The non-aqueous organic binder may be any non-aqueous organic binder material conventionally used in order to improve the physical binding force of the applied film in the production of the conductive ink. Specific, non-limiting examples of non-aqueous organic binder materials include polyvinylidene fluoride (PVDF), polymethylmethacrylate (PMMA), self-crosslinking acrylic resin emulsion, hydroxyethylcellulose, ethylhydroxyethylcellulose, carboxy (SBR), a copolymer of C1-C10 alkyl (meth) acrylate and an unsaturated carboxylic acid, gelatin, tinson (Thixoton), and the like. ), Starch, polystyrene, polyurethane, a resin containing a carboxyl group, a phenolic resin, a mixture of ethylcellulose and a phenolic resin, an ester polymer, a methacrylate polymer, a self-crosslinking (meth) acrylic acid copolymer, Ethylenically unsaturated group-containing copolymers, ethylcellulose series, acrylate series, epoxy resin series and mixtures thereof One or two or more can be selected.

As a more specific example, the non-aqueous organic binder may be a non-aqueous polymeric material having an amine value of 5 to 150 mgKOH / g. Such a non-aqueous polymeric material can simultaneously perform the role of a binder and a dispersant. In particular, the non-aqueous organic binder may be a copolymer of an unsaturated carboxylic acid or a graft polymer thereof, and may be a copolymer of an unsaturated carboxylic acid having an amine value of 5 to 150 mgKOH / g or a graft polymer thereof. Such a non-aqueous organic binder can perform the function of a binder and a dispersant at the same time, but does not interfere with the binding between the metal particles during the photo-sintering, so that a metal thin film having a more dense and more excellent conductivity can be produced. Copolymers of unsaturated carboxylic acids or graft polymers thereof having an amine value of from 5 to 150 mg KOH / g may be copolymerized with a copolymer of a C1-C10 alkyl (meth) acrylate and an unsaturated carboxylic acid, a polyisothiazole with an unsaturated carboxylic acid , Copolymers of polyacrylamide and unsaturated carboxylic acid, copolymers of polyethylene oxide and unsaturated carboxylic acid, copolymers of polyethylene glycol and unsaturated carboxylic acid, or mixtures thereof. When the copolymer is an unsaturated carboxylic acid having an amine value of 5 to 150 mgKOH / g or a graft polymer thereof, its molecular weight (weight average molecular weight) may be 1000 to 50000 g / mol.

As a non-aqueous organic binder, a commercial product containing the non-aqueous organic binder material may be used. Specific examples thereof include BYK130, BYK140, BYK160, BYK161, BYK162, BYK163, BYK164, BYK165, BYK167, BYK169, BYK170 , BYK171, BYK174 EFKA 4610, EFKA 4644, EFKA 4654, EFKA 4665, EFKA 4620, EFKA 4666, or EFKA 4642, but the present invention is not limited thereto.

The non-aqueous solvent is not particularly limited, but is preferably an alkane having 6 to 30 carbon atoms, an amine, toluene, xylene, chloroform, dichloromethane, tetradecane, octadecene, chlorobenzene, dichlorobenzene, chlorobenzoic acid, Propyl ether, and the content thereof can be adjusted so as to have suitable fluidity for coating or printing.

In one embodiment of the present invention, the ink composition for photo-sintering may contain 0.05 to 5 parts by weight of a non-aqueous organic binder and 20 to 800 parts by weight of a non-aqueous solvent based on 100 parts by weight of the metal nanoparticles.

According to an embodiment of the present invention, the non-aqueous organic binder may remain in the conductive metal thin film without impairing its inherent physical properties during photo-sintering. Accordingly, if the content of the non-aqueous organic binder in the conductive ink composition is too high, densification between the metal nanoparticles may be inhibited by the polymeric binder that binds the metal nanoparticles to the substrate. The non-aqueous organic binder in an amount of 0.05 to 5 parts by weight based on the particles has a physical strength that stably maintains the shape when the applied ink composition is dried without hindering the densification between the metal nanoparticles and forms a coating film having excellent adhesion with the substrate And at the same time, the binding force between the substrate metal thin films can be remarkably improved by the polymer binder remaining in the metal thin film after photo-sintering.

May be somewhat different depending on the application method of the conductive ink composition, but the conductive ink composition may contain a non-aqueous solvent of 20 to 800 parts by weight, so that the conductive ink composition may have a fluidity suitable for coating or printing.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an exploded perspective view of an ink composition for optical sintering according to an embodiment of the present invention; Fig. Nickel is a metal with excellent oxidation stability compared to copper and can improve moisture resistance in the production of conductive thin films.

For example, the nickel nanoparticles or the copper-nickel core shell nanoparticles may be added in an amount of 1 to 100 parts by weight based on 100 parts by weight of the metal nanoparticles, and may have enhanced moisture resistance while maintaining excellent electrical conductivity within the above range And it is possible to prevent deterioration of mechanical properties.

Further, another aspect of the present invention relates to a method for producing an ink composition for photo-sintering.

Specifically, a method for producing an ink composition for photo-sintering comprises the steps of: a) heating and stirring a first solution containing a metal precursor, an organic acid, an amine compound and a reducing agent to synthesize metal nanoparticles satisfying the following relational expression 1 ; b) dispersing the metal nanoparticles, the low melting point metal having a melting point of 800 DEG C or lower, and the non-aqueous organic binder in a nonaqueous solvent.

[Relation 1]

A ₁ / A ₂ ? 0.2

(In the equation _1, A 1 / A ₂ is an X- ray photoelectron spectroscopy spectrum phase, the metal of the metal oxide 2p _3/2 peak area (A ₁₎ on the surface of the metal nanoparticles, the metal of the metal 2p _{3 / 2} peak area (A ₂ ).)

In the step a), the step of preparing the capped metal nanoparticles may be carried out by referring to the applicant's published patent application No. 10-2013-0111180, -0111180. &Lt; / RTI &gt;

Specifically, step a) may include heating a first solution containing a metal precursor, an organic acid, an amine compound, and a reducing agent to prevent formation of a surface oxide film and to prepare capped metal nanoparticles with a capping layer . However, the heating stirring can be carried out in an inert atmosphere.

At this time, the capping layer may contain an organic acid. The organic acid can preferentially chemisorb the metal nanoparticles to form a dense organic acid film, so that the capping layer can be made of an organic acid. That is, the capping layer may be a film of organic acid chemically adsorbed on the metal nanoparticles. However, it goes without saying that a small amount of amine may be included in the capping layer in the manufacturing process using the organic acid and the amine compound together. As the metal nanoparticles are capped with a capping layer containing an organic acid, formation of a surface oxide film of the metal nanoparticles can be prevented.

The metal of the metal precursor may be one or more selected from the group consisting of copper, silver, gold, nickel, tin, aluminum and alloys thereof. The metal precursor may be one or more selected from the group consisting of nitrates, sulfates, acetates, phosphates, silicates and hydrochlorides of metals selected from the group consisting of copper, silver, gold, nickel, tin, aluminum and alloys thereof.

The organic acid has at least one form of straight chain, branched or cyclic carbon atoms having 6 to 30 carbon atoms, and may be one or more selected from saturated or unsaturated acids. More concretely, there can be mentioned oleic acid, lysine oleic acid, stearic acid, hyadroxystearic acid, linoleic acid, aminodecanoic acid, hydroxydecanoic acid, lauric acid, decenoic acid, undecenoic acid, palmitoleic acid, hexyldecano Hydroxycarboxylic acid, hydroxycarboxylic acid, succinic acid, succinic acid, succinic acid, succinic acid, succinic acid, succinic acid, succinic acid, succinic acid, In the first solution, the molar ratio of the metal precursor and the organic acid may be 1 (metal precursor): 0.2 to 4 (acid).

The amine-based compound has at least one form of straight-chain, branched or cyclic carbon atoms having 6 to 30 carbon atoms, and one or two or more of saturated and unsaturated amines can be selected. More specifically, it may be selected from hexylamine, heptylamine, octylamine, dodecylamine, 2-ethylhexylamine, 1,3-dimethyl-n-butylamine and 1-aminotridecane. The content of the amine compound in the first solution is 0.2 mole or more, preferably 1 to 50 moles, more preferably 5 to 50 moles, per mole of the metal precursor, but in the upper limit, the amine compound acts as a non-aqueous solvent So, it is not limited.

The reducing agent may be one or two or more selected from hydrazine-based reducing agents including hydrazine, hydrazine anhydride, hydrazine hydrochloride, hydrazine sulfate, hydrazine hydrate and phenylhydrazine. In addition, other hydrides; Borohydride systems including tetrabutylammonium borohydride, tetramethylammonium borohydride, tetraethylammonium borohydride, and sodium borohydride; Sodium phosphate system; And ascorbic acid; and one or more of them may be selected and used. In the first solution, the reducing agent may include a reducing agent / metal precursor molar ratio of 1 to 100.

In step a), the synthesis of the metal nanoparticles is not limited, but may be carried out at 80 to 300 ° C, more preferably 100 to 250 ° C, more preferably 130 to 200 ° C, in consideration of the reduction efficiency, Lt; / RTI &gt; It goes without saying that the metal nanoparticles can be separated and recovered by a conventional method used for nanoparticle recovery such as centrifugation.

Next, when the synthesis of the metal nano-particles satisfying the relational expression 1 is completed, the composition can be dispersed in a non-aqueous solvent together with a low-melting metal having a melting point of 800 ° C or less and a non-aqueous organic binder to prepare an ink composition for photo-sintering.

The low melting point metal having a melting point of 800 DEG C or lower can be prepared by a method similar to that of the metal nanoparticles. In addition to the precursor and the content of the low melting point metal to be produced, . &Lt; / RTI &gt;

As a specific example, a second solution containing a precursor of a low-melting-point metal to be produced, a second organic acid, a second amine compound and a second reducing agent is heated to form a copper-tin-based Alloys can be produced. However, the heating stirring can be carried out in an inert atmosphere.

At this time, the capping layer may be one containing a second organic acid. The second organic acid may preferentially chemisorption the low melting point metal particles to form a dense organic acid film, so that the second capping layer may be composed of the second organic acid. That is, the second capping layer may be a film of an organic acid chemically adsorbed on the low melting point metal particles. However, it is a matter of course that a small amount of amine may be included in the second capping layer in the manufacturing process using the second organic acid and the second amine compound. As the low melting point metal is capped with the second capping layer comprising the second organic acid, the formation of the surface oxide film of the low melting point metal can be prevented.

The precursor of the low-melting-point metal to be produced may be at least two kinds, and examples thereof may be two or more selected from the group consisting of copper, silver, gold, nickel, tin, aluminum and alloys thereof. The precursor of the low melting point metal may be one or more selected from inorganic salts consisting of nitrates, sulfates, acetates, phosphates, silicates and hydrochlorides of metals selected from the group consisting of copper, silver, gold, nickel, tin, aluminum and their alloys have.

The second organic acid has at least one form of straight chain, branched or cyclic having 6 to 30 carbon atoms, and may be one or more selected from saturated or unsaturated acids. More concretely, there can be mentioned oleic acid, lysine oleic acid, stearic acid, hyadroxystearic acid, linoleic acid, aminodecanoic acid, hydroxydecanoic acid, lauric acid, decenoic acid, undecenoic acid, palmitoleic acid, hexyldecano Hydroxycarboxylic acid, hydroxycarboxylic acid, succinic acid, succinic acid, succinic acid, succinic acid, succinic acid, succinic acid, succinic acid, succinic acid, In the second solution, the molar ratio of the precursor of the low melting point metal to the second organic acid may be 1 (precursor of the low melting point metal): 0.2 to 4 (acid).

The second amine compound has at least one form of straight chain, branched or cyclic having 6 to 30 carbon atoms, and one or more of saturated and unsaturated amines can be selected. More specifically, it may be selected from hexylamine, heptylamine, octylamine, dodecylamine, 2-ethylhexylamine, 1,3-dimethyl-n-butylamine and 1-aminotridecane. The content of the second amine compound in the first solution is 0.2 mole or more, preferably 1 to 50 moles, more preferably 5 to 50 moles, per mole of the precursor of the low melting point metal. However, in the upper limit, The compound can act as a non-aqueous solvent, so that it is not limited.

The second reducing agent may be one or more selected from hydrazine-based reducing agents including hydrazine, hydrazine anhydride, hydrazine hydrochloride, hydrazine sulfate, hydrazine hydrate and phenylhydrazine. In addition, other hydrides; Borohydride systems including tetrabutylammonium borohydride, tetramethylammonium borohydride, tetraethylammonium borohydride, and sodium borohydride; Sodium phosphate system; And ascorbic acid; and one or more of them may be selected and used. In the first solution, the second reducing agent may include a precursor mole ratio of the second reducing agent / low melting point metal of 1 to 100.

The synthesis of the low-melting metal particles is not limited, but may be carried out at 100 to 350 ° C, more preferably 140 to 300 ° C, more preferably 180 to 280 ° C, in consideration of the reduction efficiency, have. It is a matter of course that the low melting point metal particles can be separated and recovered by a conventional method used for recovery of nanoparticles such as centrifugation.

The non-aqueous organic binder may be any non-aqueous organic binder material conventionally used in order to improve the physical binding force of the applied film in the production of the conductive ink. Specific, non-limiting examples of non-aqueous organic binder materials include polyvinylidene fluoride (PVDF), polymethylmethacrylate (PMMA), self-crosslinking acrylic resin emulsion, hydroxyethylcellulose, ethylhydroxyethylcellulose, carboxy (SBR), a copolymer of C1-C10 alkyl (meth) acrylate and an unsaturated carboxylic acid, gelatin, tinson (Thixoton), and the like. ), Starch, polystyrene, polyurethane, a resin containing a carboxyl group, a phenolic resin, a mixture of ethylcellulose and a phenolic resin, an ester polymer, a methacrylate polymer, a self-crosslinking (meth) acrylic acid copolymer, Ethylenically unsaturated group-containing copolymers, ethylcellulose series, acrylate series, epoxy resin series and mixtures thereof One or two or more can be selected.

As a more specific example, the non-aqueous organic binder may be a non-aqueous polymeric material having an amine value of 5 to 150 mgKOH / g. Such a non-aqueous polymeric material can simultaneously perform the role of a binder and a dispersant. In particular, the non-aqueous organic binder may be a copolymer of an unsaturated carboxylic acid or a graft polymer thereof, and may be a copolymer of an unsaturated carboxylic acid having an amine value of 5 to 150 mgKOH / g or a graft polymer thereof. Such a non-aqueous organic binder can perform the function of a binder and a dispersant at the same time, but does not interfere with the binding between the metal particles during the photo-sintering, so that a metal thin film having a more dense and more excellent conductivity can be produced. Copolymers of unsaturated carboxylic acids or graft polymers thereof having an amine value of from 5 to 150 mg KOH / g may be copolymerized with a copolymer of a C1-C10 alkyl (meth) acrylate and an unsaturated carboxylic acid, a polyisothiazole with an unsaturated carboxylic acid , Copolymers of polyacrylamide and unsaturated carboxylic acid, copolymers of polyethylene oxide and unsaturated carboxylic acid, copolymers of polyethylene glycol and unsaturated carboxylic acid, or mixtures thereof. When the copolymer is an unsaturated carboxylic acid having an amine value of 5 to 150 mgKOH / g or a graft polymer thereof, its molecular weight (weight average molecular weight) may be 1000 to 50000 g / mol.

As a non-aqueous organic binder, a commercial product containing the non-aqueous organic binder material may be used. Specific examples thereof include BYK130, BYK140, BYK160, BYK161, BYK162, BYK163, BYK164, BYK165, BYK167, BYK169, BYK170 , BYK171, BYK174 EFKA 4610, EFKA 4644, EFKA 4654, EFKA 4665, EFKA 4620, EFKA 4666, or EFKA 4642, but the present invention is not limited thereto.

The non-aqueous solvent is not particularly limited, but is preferably an alkane having 6 to 30 carbon atoms, an amine, toluene, xylene, chloroform, dichloromethane, tetradecane, octadecene, chlorobenzene, dichlorobenzene, chlorobenzoic acid, Propyl ether, and the like.

In one example of the present invention, the ink composition for photo-sintering may contain 0.1 to 50 parts by weight of a low melting point metal, 0.05 to 5 parts by weight of a non-aqueous organic binder, and 20 to 800 parts by weight of a non-aqueous solvent &Lt; / RTI &gt;

According to an embodiment of the present invention, the non-aqueous organic binder may remain in the conductive metal thin film without impairing its inherent physical properties during photo-sintering. Accordingly, if the content of the non-aqueous organic binder in the conductive ink composition is too high, densification between the metal nanoparticles may be inhibited by the polymeric binder that binds the metal nanoparticles to the substrate. The non-aqueous organic binder in an amount of 0.05 to 5 parts by weight based on the particles has a physical strength that stably maintains the shape when the applied ink composition is dried without hindering the densification between the metal nanoparticles and forms a coating film having excellent adhesion with the substrate And at the same time, the binding force between the substrate metal thin films can be remarkably improved by the polymer binder remaining in the metal thin film after photo-sintering.

May be somewhat different depending on the application method of the conductive ink composition, but the conductive ink composition may contain a non-aqueous solvent of 20 to 800 parts by weight, so that the conductive ink composition may have a fluidity suitable for coating or printing.

Another aspect of the present invention relates to a method of manufacturing a photo-sintered conductive thin film and a photo-sintered conductive thin film produced therefrom.

In detail, the method for producing a photo-sintered conductive thin film comprises: A) metal nanoparticles satisfying the following relational expression 1; A low melting point metal having a melting point of 800 DEG C or less; Non-aqueous organic binders; And a non-aqueous solvent; B) applying the ink composition for photo-sintering to a transparent polymer substrate to form a coating film; And C) irradiating the coating film with light so as to satisfy the following relational expression 2 to produce a conductive thin film.

Step A) may be the same as that described above in the method for producing the ink composition for photo-sintering.

Specifically, step A) comprises: A-1) synthesizing metal nanoparticles satisfying the following relational expression 1 by heating and stirring a first solution containing a metal precursor, an organic acid, an amine-based compound, and a reducing agent; A-2) dispersing the metal nanoparticles, the low-melting metal having a melting point of 800 DEG C or lower, and the non-aqueous organic binder in a nonaqueous solvent.

[Relation 1]

A ₁ / A ₂ ? 0.2

(In the equation _1, A 1 / A ₂ is an X- ray photoelectron spectroscopy spectrum phase, the metal of the metal oxide 2p _3/2 peak area (A ₁₎ on the surface of the metal nanoparticles, the metal of the metal 2p _{3 / 2} peak area (A ₂ ).)

Specifically, the step (A-1) includes heating a first solution containing a metal precursor, an organic acid, an amine compound and a reducing agent to prevent the formation of a surface oxide film and to produce capped metal nanoparticles can do. However, the heating stirring can be carried out in an inert atmosphere.

At this time, the capping layer may contain an organic acid. The organic acid can preferentially chemisorb the metal nanoparticles to form a dense organic acid film, so that the capping layer can be made of an organic acid. That is, the capping layer may be a film of organic acid chemically adsorbed on the metal nanoparticles. However, it goes without saying that a small amount of amine may be included in the capping layer in the manufacturing process using the organic acid and the amine compound together. As the metal nanoparticles are capped with a capping layer containing an organic acid, formation of a surface oxide film of the metal nanoparticles can be prevented.

The metal of the metal precursor may be one or more selected from the group consisting of copper, silver, gold, nickel, tin, aluminum and alloys thereof. The metal precursor may be one or more selected from the group consisting of nitrates, sulfates, acetates, phosphates, silicates and hydrochlorides of metals selected from the group consisting of copper, silver, gold, nickel, tin, aluminum and alloys thereof.

The organic acid has at least one form of straight chain, branched or cyclic carbon atoms having 6 to 30 carbon atoms, and may be one or more selected from saturated or unsaturated acids. More concretely, there can be mentioned oleic acid, lysine oleic acid, stearic acid, hyadroxystearic acid, linoleic acid, aminodecanoic acid, hydroxydecanoic acid, lauric acid, decenoic acid, undecenoic acid, palmitoleic acid, hexyldecano Hydroxycarboxylic acid, hydroxycarboxylic acid, succinic acid, succinic acid, succinic acid, succinic acid, succinic acid, succinic acid, succinic acid, succinic acid, In the first solution, the molar ratio of the metal precursor and the organic acid may be 1 (metal precursor): 0.2 to 4 (acid).

The amine-based compound has at least one form of straight-chain, branched or cyclic carbon atoms having 6 to 30 carbon atoms, and one or two or more of saturated and unsaturated amines can be selected. More specifically, it may be selected from hexylamine, heptylamine, octylamine, dodecylamine, 2-ethylhexylamine, 1,3-dimethyl-n-butylamine and 1-aminotridecane. The content of the amine compound in the first solution is 0.2 mole or more, preferably 1 to 50 moles, more preferably 5 to 50 moles, per mole of the metal precursor, but in the upper limit, the amine compound acts as a non-aqueous solvent So, it is not limited.

The reducing agent may be one or two or more selected from hydrazine-based reducing agents including hydrazine, hydrazine anhydride, hydrazine hydrochloride, hydrazine sulfate, hydrazine hydrate and phenylhydrazine. In addition, other hydrides; Borohydride systems including tetrabutylammonium borohydride, tetramethylammonium borohydride, tetraethylammonium borohydride, and sodium borohydride; Sodium phosphate system; And ascorbic acid; and one or more of them may be selected and used. In the first solution, the reducing agent may include a reducing agent / metal precursor molar ratio of 1 to 100.

In the step A-1), the synthesis of the metal nanoparticles is not limited, but may be carried out at 80 to 300 ° C, more preferably 100 to 250 ° C, and more preferably 130 to 200 ° C in consideration of the reduction efficiency , In an inert atmosphere. It goes without saying that the metal nanoparticles can be separated and recovered by a conventional method used for nanoparticle recovery such as centrifugation.

Next, when the synthesis of the metal nano-particles satisfying the relational expression 1 is completed, the composition can be dispersed in a non-aqueous solvent together with a low-melting metal having a melting point of 800 ° C or less and a non-aqueous organic binder to prepare an ink composition for photo-sintering.

The low melting point metal having a melting point of 800 DEG C or lower can be prepared by a method similar to that of the metal nanoparticles. In addition to the precursor and the content of the low melting point metal to be produced, . &Lt; / RTI &gt;

As a specific example, a second solution containing a precursor of a low-melting-point metal to be produced, a second organic acid, a second amine compound and a second reducing agent is heated to form a copper-tin-based Alloys can be produced. However, the heating stirring can be carried out in an inert atmosphere.

At this time, the capping layer may be one containing a second organic acid. The second organic acid may preferentially chemisorption the low melting point metal particles to form a dense organic acid film, so that the second capping layer may be composed of the second organic acid. That is, the second capping layer may be a film of an organic acid chemically adsorbed on the low melting point metal particles. However, it is a matter of course that a small amount of amine may be included in the second capping layer in the manufacturing process using the second organic acid and the second amine compound. As the low melting point metal is capped with the second capping layer comprising the second organic acid, the formation of the surface oxide film of the low melting point metal can be prevented.

The precursor of the low-melting-point metal to be produced may be at least two kinds, and examples thereof may be two or more selected from the group consisting of copper, silver, gold, nickel, tin, aluminum and alloys thereof. The precursor of the low melting point metal may be one or more selected from inorganic salts consisting of nitrates, sulfates, acetates, phosphates, silicates and hydrochlorides of metals selected from the group consisting of copper, silver, gold, nickel, tin, aluminum and their alloys have.

The second organic acid has at least one form of straight chain, branched or cyclic having 6 to 30 carbon atoms, and may be one or more selected from saturated or unsaturated acids. More concretely, there can be mentioned oleic acid, lysine oleic acid, stearic acid, hyadroxystearic acid, linoleic acid, aminodecanoic acid, hydroxydecanoic acid, lauric acid, decenoic acid, undecenoic acid, palmitoleic acid, hexyldecano Hydroxycarboxylic acid, hydroxycarboxylic acid, succinic acid, succinic acid, succinic acid, succinic acid, succinic acid, succinic acid, succinic acid, succinic acid, In the second solution, the molar ratio of the precursor of the low melting point metal to the second organic acid may be 1 (precursor of the low melting point metal): 0.2 to 4 (acid).

The second amine compound has at least one form of straight chain, branched or cyclic having 6 to 30 carbon atoms, and one or more of saturated and unsaturated amines can be selected. More specifically, it may be selected from hexylamine, heptylamine, octylamine, dodecylamine, 2-ethylhexylamine, 1,3-dimethyl-n-butylamine and 1-aminotridecane. The content of the second amine compound in the first solution is 0.2 mole or more, preferably 1 to 50 moles, more preferably 5 to 50 moles, per mole of the precursor of the low melting point metal. However, in the upper limit, The compound can act as a non-aqueous solvent, so that it is not limited.

The second reducing agent may be one or more selected from hydrazine-based reducing agents including hydrazine, hydrazine anhydride, hydrazine hydrochloride, hydrazine sulfate, hydrazine hydrate and phenylhydrazine. In addition, other hydrides; Borohydride systems including tetrabutylammonium borohydride, tetramethylammonium borohydride, tetraethylammonium borohydride, and sodium borohydride; Sodium phosphate system; And ascorbic acid; and one or more of them may be selected and used. In the first solution, the second reducing agent may include a precursor mole ratio of the second reducing agent / low melting point metal of 1 to 100.

The synthesis of the low-melting metal particles is not limited, but may be carried out at 100 to 350 ° C, more preferably 140 to 300 ° C, more preferably 180 to 280 ° C, in consideration of the reduction efficiency, have. It is a matter of course that the low melting point metal particles can be separated and recovered by a conventional method used for recovery of nanoparticles such as centrifugation.

The non-aqueous organic binder may be any non-aqueous organic binder material conventionally used in order to improve the physical binding force of the applied film in the production of the conductive ink. Specific, non-limiting examples of non-aqueous organic binder materials include polyvinylidene fluoride (PVDF), polymethylmethacrylate (PMMA), self-crosslinking acrylic resin emulsion, hydroxyethylcellulose, ethylhydroxyethylcellulose, carboxy (SBR), a copolymer of C1-C10 alkyl (meth) acrylate and an unsaturated carboxylic acid, gelatin, tinson (Thixoton), and the like. ), Starch, polystyrene, polyurethane, a resin containing a carboxyl group, a phenolic resin, a mixture of ethylcellulose and a phenolic resin, an ester polymer, a methacrylate polymer, a self-crosslinking (meth) acrylic acid copolymer, Ethylenically unsaturated group-containing copolymers, ethylcellulose series, acrylate series, epoxy resin series and mixtures thereof One or two or more can be selected.

As a more specific example, the non-aqueous organic binder may be a non-aqueous polymeric material having an amine value of 5 to 150 mgKOH / g. Such a non-aqueous polymeric material can simultaneously perform the role of a binder and a dispersant. In particular, the non-aqueous organic binder may be a copolymer of an unsaturated carboxylic acid or a graft polymer thereof, and may be a copolymer of an unsaturated carboxylic acid having an amine value of 5 to 150 mgKOH / g or a graft polymer thereof. Such a non-aqueous organic binder can perform the function of a binder and a dispersant at the same time, but does not interfere with the binding between the metal particles during the photo-sintering, so that a metal thin film having a more dense and more excellent conductivity can be produced. Copolymers of unsaturated carboxylic acids or graft polymers thereof having an amine value of from 5 to 150 mg KOH / g may be copolymerized with a copolymer of a C1-C10 alkyl (meth) acrylate and an unsaturated carboxylic acid, a polyisothiazole with an unsaturated carboxylic acid , Copolymers of polyacrylamide and unsaturated carboxylic acid, copolymers of polyethylene oxide and unsaturated carboxylic acid, copolymers of polyethylene glycol and unsaturated carboxylic acid, or mixtures thereof. When the copolymer is an unsaturated carboxylic acid having an amine value of 5 to 150 mgKOH / g or a graft polymer thereof, its molecular weight (weight average molecular weight) may be 1000 to 50000 g / mol.

As a non-aqueous organic binder, a commercial product containing the non-aqueous organic binder material may be used. Specific examples thereof include BYK130, BYK140, BYK160, BYK161, BYK162, BYK163, BYK164, BYK165, BYK167, BYK169, BYK170 , BYK171, BYK174 EFKA 4610, EFKA 4644, EFKA 4654, EFKA 4665, EFKA 4620, EFKA 4666, or EFKA 4642, but the present invention is not limited thereto.

The non-aqueous solvent is not particularly limited, but is preferably an alkane having 6 to 30 carbon atoms, an amine, toluene, xylene, chloroform, dichloromethane, tetradecane, octadecene, chlorobenzene, dichlorobenzene, chlorobenzoic acid, Propyl ether, and the like.

In one example of the present invention, the ink composition for photo-sintering may contain 0.1 to 50 parts by weight of a low melting point metal, 0.05 to 5 parts by weight of a non-aqueous organic binder, and 20 to 800 parts by weight of a non-aqueous solvent &Lt; / RTI &gt;

According to an embodiment of the present invention, the non-aqueous organic binder may remain in the conductive metal thin film without impairing its inherent physical properties during photo-sintering. Accordingly, if the content of the non-aqueous organic binder in the conductive ink composition is too high, densification between the metal nanoparticles may be inhibited by the polymeric binder that binds the metal nanoparticles to the substrate. The non-aqueous organic binder in an amount of 0.05 to 5 parts by weight based on the particles has a physical strength that stably maintains the shape when the applied ink composition is dried without hindering the densification between the metal nanoparticles and forms a coating film having excellent adhesion with the substrate And at the same time, the binding force between the substrate metal thin films can be remarkably improved by the polymer binder remaining in the metal thin film after photo-sintering.

May be somewhat different depending on the application method of the conductive ink composition, but the conductive ink composition may contain a non-aqueous solvent of 20 to 800 parts by weight, so that the conductive ink composition may have a fluidity suitable for coating or printing.

In step B) according to an example, the application of the ink composition for light-sintering may be carried out by a method of coating or printing. As a specific example, the coating can be performed using dip coating, spin coating, spray coating or casting, and the printing can be performed by screen printing, inkjet printing, electrostatic hydraulic printing, microcontact printing, imprinting, gravure printing, reverse offset printing Or gravure offset printing. The application of the ink composition for photo-sintering may be applied with appropriate patterns according to the design of the product to be manufactured. Alternatively, after the ink composition for photo-sintering is applied to the transparent polymer substrate, It goes without saying that drying to volatilize the solvent may be performed.

The transparent polymer substrate to which the ink composition for photo-sintering is applied can be any transparent substrate having insulating properties according to the features of the present invention described above.

For example, a polyethylene terephthalate (PET) substrate has excellent flexibility, is excellent in light transmittance, has excellent chemical stability to an organic solvent, does not adsorb water well, and can be formed by melt-extrusion, which is a low- Great value. However, since the maximum process temperature of the polyethylene terephthalate substrate is at a level of 80 to 150 캜, there is a great difficulty in forming a conductive thin film substantially on the polyethylene terephthalate substrate. However, the manufacturing method according to an embodiment of the present invention can produce a conductive thin film through extremely low light energy, and thus, as shown in Examples to be described later, a polyethylene terephthalate substrate requiring an extremely low process temperature has excellent electrical conductivity Can be produced.

As described above, according to the features of the present invention, the substrate can be any transparent substrate having an insulating property, and specific and non-limiting examples thereof include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), poly Organic substrates such as polyethylene terephthalate (PET), polycarbonate (PC), polyarylate (PAR), polyether sulfone (PES) or polyimide (PI).

Step C) is a step of producing a conductive thin film through light sintering. In general, sintering of metal nanoparticles during light sintering is known to cause the surface area of metal nanoparticles to be instantaneously melted by the high energy applied by light. In order to sinter these metal nanoparticles, Lt; 2 &gt; or more. On the other hand, when the ink composition for photo-sintering according to the present invention is used, excellent sintering ability can be obtained even when light is irradiated at an extremely low intensity.

In detail, in the step C), the conductive thin film can be produced by irradiating the coating film with light so as to satisfy the following relational expression (2).

[Relation 2]

I _LS ≤ I _c

In the relational expression 2, I _LS is the energy (J / cm 2) of the light irradiated onto the coating film, and I _c is the maximum energy (J / cm 2) of the light in which the transparent polymer substrate is not deteriorated.

The method of manufacturing a photo-sintered conductive thin film according to an embodiment of the present invention can produce a conductive thin film having excellent sintering ability by irradiating extremely low intensity light satisfying the following relational expression 2, A low-priced transparent polymer substrate such as polyethylene naphthalate (PEN) or polyethylene terephthalate (PET) does not deteriorate, and the light-sintered metal thin film has electric conductivity equivalent to that of bulk, and a conductive thin film There is an advantage to be able to do.

Such optical sintering conditions (the condition of relational expression 2) are not known in the field of metal wiring manufacturing methods using conventional light sintering, and under the conditions not studied, metal nanoparticles satisfying Relation 1 and low Is a condition that may be present in the case of photo-sintering an ink composition containing a melting point metal.

That is, the manufacturing method according to the present invention can have a characteristic configuration in which the energy of light sintered to have electrical conductivity comparable to that of the bulk is lower than the energy of light that deteriorates the low-cost transparent polymer substrate.

The light sintering condition of the relational expression 2 is very surprising to those skilled in the field of optical sintering using metal nanoparticles. In general, sintering of metal nanoparticles during light sintering is known to cause the surface area of metal nanoparticles to be instantaneously melted by the high energy applied by light. In order to sinter these metal nanoparticles, Lt; 2 &gt; or more. However, at a high temperature (instantaneous high temperature) condition such that at least the surface area of metal nanoparticles is instantaneously melted, the low-cost transparent polymer substrate is inevitably lost its properties and deteriorated. Substantially, inexpensive transparent polymer substrates such as polyethersulfone (PES), polyethylene naphthalate (PEN) or polyethylene terephthalate (PET) are deformed at the time of continuous irradiation of light having a light quantity of 2 J / cm 2 or more. However, when the densification (sintering) mechanism of the surface melting of the metal nanoparticles is taken into account, the low-cost transparent polymer substrate can be made of metal nanoparticles satisfying relational expression 1 and low melting point metal , It means that sintering of the ink composition can be made so as to have electric conductivity comparable to that of the bulk.

As described above, the manufacturing method according to an exemplary embodiment of the present invention is a method of manufacturing a conductive metal thin film having an electrical conductivity comparable to that of a bulk but remaining a polymeric binder, Can be manufactured.

Since the method according to an embodiment of the present invention is excellent in thermal stability to such an extent that the polymeric binder mixed with the metal nanoparticles can remain, even if a substrate having an upper limit of the process temperature of 200 ° C or less is used, And the bonding strength between the metal thin film and the substrate is extremely excellent due to the residual polymer binder, so that it is possible to manufacture a conductive metal thin film suitable for flexible parts. In addition, since a light sintering process can be used, it is possible to manufacture a large area in a very short time in the atmosphere, which is advantageous in optical resolution, and it is possible to realize a roll-to-roll process, There are advantages.

As a specific example, the step C) may be irradiated with light having an energy of 1.3 J / cm 2 or less. In particular, in the case of an ink composition for photo-sintering comprising copper metal nanoparticles and a copper-tin-based alloy, it can be sintered through light irradiation with extremely low energy of 1.3 J / cm 2 or less, It can have excellent electric conductivity.

In the manufacturing method according to an embodiment of the present invention, step C) may be performed by successively irradiating light of a wavelength band of 200 to 800 nm. Light in a wavelength band of 200 to 800 nm is a wavelength band including light in a visible light band. Such light of 200 to 800 nm is irradiated to cause light sintering between metal nanoparticles, thereby minimizing thermal damage to the substrate .

More specifically, step C) may be performed by successively irradiating light in a wavelength band of 370 to 800 nm, more specifically, light in a wavelength band of 400 to 800 nm. The irradiation of the light of the wavelength band of 370 to 800 nm, specifically the light of the wavelength band of 400 to 800 nm, means that light is sintered by visible light rather than ultraviolet rays having strong energy.

Light sintering by visible light is a constitution possible by capping with a capping layer containing an organic acid to prevent the formation of a surface oxide film and photo-sintering metal nanoparticles whose surface maintains properties of metals other than oxides. As the light sintering is performed by visible light irradiation, the ultraviolet light irradiation substrate can be remarkably free from thermal damage.

In the manufacturing method according to an embodiment of the present invention, step C) may be performed in which light is continuously irradiated for 1 to 2 msec. That is, according to an embodiment of the present invention, light can be irradiated for a very short time of 1 to 2 msec to produce a conductive thin film which is a completely uniform phase-formed solid solution. In order to prevent damages to the substrate and sintering at a minimum temperature as light of high energy is irradiated for sintering the metal nanoparticles during the light sintering of the ink containing the conventional metal nanoparticles, Light is irradiated in a pulse form.

However, according to one embodiment of the present invention, it is not necessary to design a pulse width, a pulse gap, a pulse number, and the like, which should be individually specified for each substrate by the thickness of the metal thin film to be manufactured, (Continuously irradiating light) for a long period of time, so that stable light sintering can be performed.

The time of light irradiation can affect the substantial temperature of the thin film (the film to which the light is irradiated) and the substantial temperature of the substrate during the light sintering process due to the accumulation of heat generated by the light. The irradiation time of the light can be appropriately changed in consideration of the material of the substrate and the like. However, light having a wavelength band of 200 to 800 nm, preferably wavelength of 370 to 800 nm, having an energy of 1.3 J / More preferably, when light in a wavelength band of 400 to 800 nm is continuously irradiated in a time of less than 2 msec, inhomogeneous light sintering may occur and there is a danger that the production of a large-area metal thin film may be difficult, There is a risk of damage to the substrate, such as a polyethylene terephthalate substrate, which has poor heat resistance characteristics due to accumulated heat.

It is needless to say that, in the photo-sintering process, the coating film may be dried after the ink is coated on the substrate in a designed pattern so as to form a coating film, and the drying may be performed at room temperature. The substrate on which the coating film is formed can be irradiated with light. That is, in the entire region of the substrate on which the coating film is formed, light having a wavelength of 200 to 800 nm, preferably light having a wavelength of 370 to 800 nm, more preferably 400 to 800 nm, Band light, preferably for 1 to 2 msec.

In the manufacturing method according to an embodiment of the present invention, light having an energy of 1.3 J / cm 2 or less at the time of light irradiation and irradiating light having intensity higher than that at which the metal nanoparticles are sintered can be irradiated. Specifically, when the light intensity to be irradiated is 0.9 J / cm 2 or more, light sintering of metal nanoparticles may occur.

The thickness of the light-sintered conductive thin film produced by such a manufacturing method is not particularly limited, but may be 0.1 to 50 탆.

Hereinafter, a method for producing an ink composition for photo-sintering and a method for producing a photo-sintering conductive thin film according to the present invention will be described in more detail with reference to the following examples. It should be understood, however, that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention.

Unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

In addition, the unit of the additives not specifically described in the specification may be% by weight.

[Production Example 1]

(0.110 mol) was added to the reaction mixture, and then the mixture was heated to 90 ° C. to remove the reducing agent, phenylhydrazine, 1.960 mol) was injected to prepare a reaction solution. The reaction temperature was raised to 150 ° C and the reaction was continued for 5 minutes. After cooling to room temperature, the particles were extracted by centrifugation and washed with toluene to synthesize copper nano particles having an average size of 60 nm.

The copper nanoparticles thus prepared were analyzed by a transmission electron microscope and it was found from FIG. 1 that a capping layer having a thickness of about 1 nm was formed on the copper core of the monocrystal. It was confirmed by X-ray photoelectron spectroscopy that C 1s and O 1s peaks , It was confirmed that capping layer was formed by oleic acid having an alkyl chain (CC) and a carboxylate (-COO ^- ) moiety.

In addition, analysis of the X- ray photoelectron spectrum of the copper nano-particles, as the capping by the capping layer to check that the surface oxide film forming the protection, substantially from 2 to A ₁ / A ₂ is ranging from 0 Can be confirmed.

[Production Example 2]

(0.015 mol), copper acetate (0.014 mol) and tin (II) 2-ethylhexanoate (0.005 mol) were mixed in a nitrogen atmosphere, and then the mixture was heated to 220 ° C. And the reaction solution was prepared by injecting phenylhydrazine (0.261 mol) as a reducing agent. After reacting for 60 minutes and cooling to room temperature, the particles were extracted by centrifugation and washed with toluene to synthesize core-shell type copper nanoparticles whose surface was coated with Sn ₃ Cu ₁₀ having an average size of 50 nm, The weight ratio of synthesized copper: Sn ₃ Cu ₁₀ was 73.8: 16.8. The shapes of the synthesized core-shell nanoparticles are shown in FIGS. 3 and 4, and the crystal phase is shown in FIG.

[Production Example 3]

(0.0135 mol), copper acetate (0.014 mol) and nickel (Ⅱ) acetylacetonate (0.019 mol) were mixed in a nitrogen atmosphere and the temperature was raised to 220 ° C., Hydrazine (0.261 mol) was injected to prepare a reaction solution. After reacting for 60 minutes and cooling to room temperature, the particles were extracted by centrifugation and washed with toluene to synthesize nickel nanoparticles having an average size of 40 nm.

[Example 1]

The copper nanoparticles prepared in Preparation Example 1 and the core-shell nanoparticles prepared in Preparation Example 2 were mixed to prepare mixed nanoparticles such that the weight ratio of Cu: Sn ₃ Cu ₁₀ was 95: 5. 0.7 g of the mixed nanoparticles and 7 mg of BYK130 as a polymeric binder material were mixed with 99.3 g of toluene and then spray-coated to form a coating film on a polyimide substrate heated to 80 캜. (Irradiation time (msec), voltage (kV), and light amount (J / cm 2)] is 1.0 or 2.3 using a light source having a wavelength band of 370-800 nm (linear B-type for Xenon PLA-2010 sintering system) 1.5, 1.8, 0.97], [1.5, 1.9, 1.1], [1.5, 2.0, 1.22], [1.5, 2.3, 1.63 2.0, 2.0, 1.63], [2.0, 2.3, 2.16] or [2.0, 2.5, 2.52] The thickness of the conductive thin film was 400 ~ 800 ㎚ by irradiating light as much as possible. It was confirmed that the metal thin film was not removed during the adhesion test between the metal thin film and the substrate.

The resistivity of the prepared conductive metal thin film was measured using a 4-point probe. In addition, for the long - term stability test, the change in resistance with the storage time at 85% / 85C under high temperature and high humidity condition was measured by using the conductive thin film prepared by irradiating light with [1.5 msec, 1.8 kV, 0.97 J / This is shown in Fig.

Light sintering condition
(msec, kV) Light quantity (J / cm2) Resistivity (μΩcm) 1.0, 2.3 1.04 10.59 1.0, 2.5 1.21 9.12 1.0, 3.0 1.74 11.85 1.5, 1.8 0.97 47.7 1.5, 1.9 1.1 11.85 1.5, 2.0 1.22 10.05 1.5, 2.3 1.63 8.79 1.5, 2.5 1.9 10.41 2.0, 1.8 1.3 14.1 2.0, 1.9 1.46 12.96 2.0, 2.0 1.63 8.82 2.0, 2.3 2.16 7.92 2.0, 2.5 2.52 9.84

[Example 2]

The copper-nanoparticles prepared in Preparation Example 1, the core-shell nanoparticles prepared in Preparation Example 2 and the nickel nanoparticles prepared in Preparation Example 3 were mixed to prepare Cu: Sn ₃ Cu ₁₀ : Ni in a weight ratio of 66.5: 3.5: 30 to prepare mixed nanoparticles and the light sintering conditions were different. The photoluminescence was irradiated with light of [1.5 msec, 2.0 kV, 1.22 J / cm2] to produce a conductive thin film having a thickness of 400 nm. The resistivity of the conductive thin film was 51.7 μΩcm, The resistance change of 85C according to the storage time under the high temperature and high humidity condition was analyzed, and it is shown in FIG.

[Comparative Example 1]

All the processes except that the copper nanoparticles prepared in Preparation Example 1 alone and the light sintering conditions were different were carried out in the same manner as in Example 1. The conductive thin film was prepared by irradiating light of [1.5 msec, 2.3 ㎸, 1.63 J / ㎠] to the light treatment. The resistivity of the conductive thin film was 7 μΩcm and 85% / The resistance change of 85C according to the storage time under the high temperature and high humidity condition was analyzed, and it is shown in FIG.

[Comparative Example 2]

All the steps other than the light treatment conditions were carried out in the same manner as in Comparative Example 1. The light was irradiated with light of [1.5 msec, 3.0 ㎸, 2.67 J / ㎠], and it was confirmed that the metal thin film partially peeled off.

This was analyzed by X-ray photoelectron spectroscopy (XPS), and the content of the polymeric binder remaining in the metal thin film was measured according to the amount of light to be irradiated. As a result, in the examples, light was irradiated in excess of 1.3 J / In the case of the metal thin film produced, it was confirmed that the polymer binder was substantially degraded.

On the other hand, in the case of a metal thin film produced by irradiating a light amount of 1.3 J / cm 2 or less, 60 wt% or more of the polymer binder contained in the dried film before light irradiation remains in the metal thin film even after light irradiation, It was found that this remarkably improved metal thin film was produced.

Claims (14)

Metal nanoparticles satisfying the following relational expression 1; A low melting point metal having a melting point of 800 DEG C or less; Non-aqueous organic binders; And a non-aqueous solvent.
[Relation 1]
A ₁ / A ₂ ? 0.2
(In the equation _1, A 1 / A ₂ is an X- ray photoelectron spectroscopy spectrum phase, the metal of the metal oxide 2p _3/2 peak area (A ₁₎ on the surface of the metal nanoparticles, the metal of the metal 2p _{3 / 2} peak area (A ₂ ).)
The method according to claim 1,
Wherein the low melting point metal is an alloy composed of two or more metals selected from copper, tin, silver, bismuth, zinc, indium and lead.
3. The method of claim 2,
Wherein the low-melting-point metal is a copper-tin-based alloy.
The method of claim 3,
Wherein the copper-tin-based alloy satisfies the following formula (1).
[Chemical Formula 1]
Cu ₁ Sn _x
(In the formula (1), x is 0.1? X? 2.)
5. The method of claim 4,
Wherein the copper-tin-based alloy is added in an amount of 0.1 to 50 parts by weight based on 100 parts by weight of the metal nanoparticles.
The method according to claim 1,
Wherein the metal nanoparticles are any one or two or more selected from among copper, silver, gold, nickel, tin, aluminum, and alloys thereof.
The method according to claim 6,
Wherein the ink composition further comprises nickel nanoparticles or copper-nickel core-shell nanoparticles.
8. The method of claim 7,
Wherein the nickel nanoparticles or the copper-nickel core shell nanoparticles are added in an amount of 1 to 100 parts by weight based on 100 parts by weight of the metal nanoparticles.
a) heating and stirring a first solution containing a metal precursor, an organic acid, an amine compound and a reducing agent to synthesize metal nanoparticles which are capped with a capping layer to satisfy the following relational expression 1;
b) dispersing the metal nanoparticles, the low melting point metal having a melting point of 800 DEG C or lower, and the non-aqueous organic binder in a nonaqueous solvent;
Wherein the ink composition for light-sintering comprises:
[Relation 1]
A ₁ / A ₂ ? 0.2
(In the equation _1, A 1 / A ₂ is an X- ray photoelectron spectroscopy spectrum phase, the metal of the metal oxide 2p _3/2 peak area (A ₁₎ on the surface of the metal nanoparticles, the metal of the metal 2p _{3 / 2} peak area (A ₂ ).)
A) metal nanoparticles satisfying the following relational expression 1; A low melting point metal having a melting point of 800 DEG C or less; Non-aqueous organic binders; And a non-aqueous solvent;
B) applying the ink composition for photo-sintering to a transparent polymer substrate to form a coating film; And
C) irradiating the coating film with light so as to satisfy the following relational expression 2 to produce a conductive thin film;
Wherein the light-sintering conductive thin film has a thickness of 100 nm or less.
[Relation 1]
A ₁ / A ₂ ? 0.2
[Relation 2]
I _LS ≤ I _c
(In the equation _1, A 1 / A ₂ is an X- ray photoelectron spectroscopy spectrum phase, the metal of the metal oxide 2p _3/2 peak area (A ₁₎ on the surface of the metal nanoparticles, the metal of the metal 2p _{3 / 2} peak area (A &lt; ₂ &gt;),
In the relational expression 2, I _LS is the energy (J / cm 2) of the light irradiated onto the coating film, and I _c is the maximum energy (J / cm 2) of the light in which the transparent polymer substrate is not deteriorated.
11. The method of claim 10,
Wherein the step (C) irradiates light having an intensity of 1.3 J / cm2 or less.
12. The method of claim 11,
Wherein the step (C) comprises continuously irradiating light having a wavelength band of 200 to 800 nm.
13. The method of claim 12,
And the step (C) is a step of continuously irradiating light for 1 to 2 msec.
A photo-sintering conductive thin film produced by the method of any one of claims 10 to 13.

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