KR101233241B1 - Ultra Violet Curing Conductive Paste Composition for Touch Panels, Touch Panels Containing the Composition and Manufacturing Process of the Composition - Google Patents

Abstract

The present invention relates to an ultraviolet curable paste composition for a touch screen panel, a method for producing the composition, and a film for a touch panel containing the composition. According to the present invention, a thermal shock is applied to an electronic device and a printed coating film having a touch screen panel, which may be caused when patterning a film of a touch screen panel using a conventional heat-curable paste using a paste composition curable at room temperature. It can be prevented from deteriorating, it is possible to shorten the production process time to improve productivity, as well as to improve the physical properties of the print film.

Description

Ultraviolet Curing Conductive Paste Composition for Touch Panels, Touch Panels Comprising the Same and Method for Making the Compositions {Ultra Violet Curing Conductive Paste Composition for Touch Panels, Touch Panels Containing the Composition and Manufacturing Process of the Composition}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to electrode paste compositions for use in electrode formation, packaging or assembly of various electrical and electronic materials. UV curable conductive paste composition, a method for producing the conductive paste composition, a conductive paste composition, a touch panel utilizing the composition, and a method for producing the composition.

BACKGROUND With the recent rapid spread of electronic communication devices, interest in elements constituting these devices has been amplified. There is an increasing interest in printing electronic devices related to displays such as flat panel display panels, RFID, batteries, and organic transistors. Among them, the touch screen panel is attracting attention as the touch screen panel, which was mainly used in industrial products such as ATMs and kiosks, is applied to portable electronic devices such as smartphones and navigation. Touch screen panels, also called touch panels, do not use an input device such as a keyboard or a mouse, and when a person's hand or a separate object comes into contact with a character or a specific position on the screen, the touch screen panel detects the position and performs a specific function. Means a panel to be processed.

The touch screen panel is basically composed of a touch panel, a controller, and driver software. The touch panel is composed of a top film and a bottom film (or glass) on which a transparent conductive thin film such as indium tin oxide (ITO) is deposited. When the input coordinates according to the presence or absence of the touch input are detected and transmitted to the controller, the controller converts the signal transmitted from the touch panel into a digital signal and outputs the coordinates on the display, and the driver software receives the signal received from the controller and touches it. Panels implement accordingly.

The touch screen panel is a resistive method that generates an electrical signal when the upper and lower electrode layers are contacted according to the pressure of a finger by bonding two substrates coated with a transparent electrode. Ii) Capacitive method for detecting static electricity generated in the human body, i) SAW (Surface Accoustic Wave) method for detecting the decrease of wave size when the emitted ultrasound meets obstacles Branches are classified into infrared (Infrared, IR) methods that use the property of blocking infrared rays when they meet obstacles, and a resistive film method and a capacitive method are mainly used.

However, as described above, a film must be configured on one surface of the transparent conductive layer of the touch panel which detects input coordinates according to the presence or absence of a finger or the like among the touch screen panels and transmits them to the controller. However, in the related art, after forming a conductive paste, the transparent paste is patterned on the transparent conductive thin film through screen printing, and then laminated on the conductive thin film in the form of a film by a curing process by heat. That is, the paste used for the upper film for conventional touch panels was basically cured by a thermal curing method. Since this method requires heat drying time, not only does the cost of the entire production process increase due to the use of energy, but also the heat used during the curing process causes various electronic materials and printed coating films forming the touch screen panel to be subjected to thermal shock. There is a problem such as deterioration or shrinkage by. In particular, the difficulty of the working environment due to the organic solvent used to manufacture the thermosetting paste also remained a problem to be solved.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a conductive paste composition which can be used for a touch screen and / or a touch panel as an ultraviolet curable rather than a heat curable, and a method of manufacturing the same.

It is also an object of the present invention to provide a touch panel having an electrode pattern excellent in printability, adhesion, and electrical conductivity with a transparent electrode, by using a conductive paste composition for an ultraviolet (UV) curable touch panel suitable for screen printing. .

In addition, another object of the present invention is to provide a method for producing the aforementioned conductive paste composition.

Other objects and advantages of the present invention will become more apparent from the drawings and accompanying drawings.

According to an aspect of the present invention having the above object, 60 to 80% by weight of a conductive inorganic powder; Provided is a conductive paste composition for a touch panel including 20 to 40% by weight of an ultraviolet curable binder containing a resin solid content of a polyester acrylate oligomer.

At this time, the ultraviolet curable binder is a polyester-based acrylate oligomer having a glass transition temperature of 5 to 40 ℃ number average molecular weight is in the range of 1000 to 5000 and composed of ultraviolet curable polyester acrylate oligomer having 3 to 5 reactors. A first binder; 2nd containing 60-80 weight part of resin solids which are polyester acrylate oligomers which have a glass transition temperature of 5-40 degreeC, number average molecular weights 3000-8000, and 4-6 reactors, and 20-40 weight part of dilution solvents A binder may be included, and preferably, 5 to 20 parts by weight of the first binder and 5 to 20 parts by weight of the second binder with respect to 100 parts by weight of the conductive paste composition for the touch panel.

According to an embodiment of the present invention, the conductive inorganic powder includes a silver powder, and the silver powder has a thickness of 30 to 40 nm, a size of 1 to 5 μm, a thickness of 70 to 80 nm, and a size of 1 to 4 It is possible to mix and use a plate-shaped powder of μm.

Meanwhile, according to the present invention, there is also provided a touch panel including a conductive film for a touch panel including the aforementioned conductive paste composition, and a transparent conductive thin film coated by such a touch panel conductive film.

In addition, according to another aspect of the present invention, as a method of manufacturing a conductive paste for a touch panel, (a) 7 to 25 parts by weight of an ultraviolet curable polyester acrylate oligomer based on 100 parts by weight of the conductive paste for a touch panel, acrylic Preparing a binder by mixing 5 to 20 parts by weight of a monomer having a rate functional group and 3 to 15 parts by weight of a binder dilution solvent; (b) adding 60 to 80 parts by weight of the conductive inorganic powder to 100 parts by weight of the conductive paste composition for the touch panel to the obtained binder, followed by stirring the mixture to obtain a first paste; And (c) dissolving the photocuring initiator in a paste dilution solvent, followed by stirring with the first paste to obtain a second paste.

At this time, the monomer is 2-hydroxypropyl acrylate (2-Hydroxypropyl acrylate, HPA), 4-hydroxybutyl acrylate (4-Hydroxybutyl acrylate, 4-HBA), polyethylene glycol diacrylate (Polyethyleneglycol diacrylate, 9EGDA)), Neopentylglycol Hydroxypivalate diacrylate modified caprolactone, Bisphenol A diacrylate, Trimethylolpropane triacrylate (TMPTA) ), Trimethylolpropane triacrylate-modified ethylene oxide, dipentaerythritol triacrylate, pentaerythritol tryacrylate (PETA), ditrimethylol Propane tetraacrylate (Dipenta tetraacrylate (DTMPTA)), dipenta Lithitol hexaacrylate (Dipentaerythritol hexaacrylate (DPHA)) or dipentaerythritol hexaacrylate-modified caprolactone (Dipentaerythritol hexaacrylate modified caprolactone), hexanediol diacrylate (Hexanedioldiacrylate (HDDA), octyl decyl acrylate) acrylate, ODA), trimethylopropane trisacrylate (TMPTA), isobonyl acrylate (IBOA), tetraethyleneglycol dicarylate (TTEGDA), ethoxylated trimethylpropane triacrylic It may be a material selected from the group consisting of latex (Ethoxylated trimethylopropane triacrylate, TM3EOTA) and combinations thereof.

In addition, the binder dilution solvent and paste dilution solvent terpineol (terpineol), N-methylpyrrolidone (N-methylpyrrolidone), butyl cellosolve (butyl cellosolve), ethylene glycol monobutyl ether acetate (Ethylene glycol monobutyl ether acetate ), Ethyl carbitol, ethyl cabitol acetate, butyl carbitol, butyl cabitol, ethoxyethyl acetate, ethyl cellosolve, ethyl cellosolve acetate ( ethyl cellosolve acetate, butyl acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, gamma-butyrolactone, methyl It is preferably a substance selected from ethyl ethyl ketone and combinations thereof.

The photocuring initiator is benzophenone (Benzophenone); Chloroacetophenon, including trichloroacetophenone; Diethoxy acetophenone (DEAP); 1-phenyl-2-hydroxy-2-methyl propane-1one (1-phenyl-2-hydroxy-2-methyl propane-1-one); 1-Hydroxycyclohexyl-phenylketone, 2-hydroxy-2-methyl-1-phenyl-1-propan-1-one (2-Hydroxy-2-methyl-1-phenyl hydroxyacetophenon, including -propane-1-on; 2-benzyl-2- (dimethylamino) -4'-morpholinobutyrophenone); 2-benzyl-2- (dimethylamino) -4'-morpholinobutyrophenone;Alpha-aminoacetophenone; Bis (h5-2,4, -cyclopentadien-1-yl) bis [2,6-difluoro-3- (1H-pyrrol-1-yl) phenyltitanium (bis (h5-2,4-cyclopentadien -1-yl) bis [2,6-difluoro-3- (1H-pyrrol-1-yl) phenyl] -titanium); Bis (2,4,6-trimethylbenzoyl) -phenylphosphineoxide (Bis (2,4,6-trimethylbenzoyl) -phenylphosphineoxide), 2-methyl-1- [4-methylthio] phenyl-2-morpholino Propane-1-one (2-methyl-1 [4-methylthio] phenyl-2-morphorinopropane-1-on), 2,3,6-trimethylbenzoyl phenyl ethoxyphosphine oxide (2,3,6-Trimethylbenzoyl phenyl ethoxyphosphine oxide), 2,4-diethylthioxanthone, and isopropyl thioxthanthone, or a combination thereof.

In the present invention, a conductive paste for an ultraviolet curable touch panel suitable for screen printing may be manufactured, and an electrode pattern having excellent printability, adhesion, and electrical conductivity, which are transparent conductive thin films of the touch panel, may be obtained.

In particular, since the paste of the present invention is cured at room temperature by ultraviolet rays, not only does not deteriorate an electronic device due to heat, but also shortens the production process time compared to the conventional thermal curing method, which has good physical properties and productivity of the printed film. This high environmentally friendly work was made possible.

In addition, not only good physical properties such as adhesion, hardness and resistance, but also screen printing for reproducing fine patterns were possible.

1 is a diagram schematically illustrating a process for producing a conductive paste composition according to the present invention.
Figure 2 is a graph measuring the viscosity of the rheological properties of the film prepared using the conductive paste composition prepared according to the present invention.
Figure 3 is a graph measuring the surface resistance of the film produced using the conductive paste composition prepared according to the present invention.
Figure 4 is a graph measuring the line resistance of the film produced using the conductive paste composition prepared according to the present invention.
5a to 5e are photographs of the sharpness of the ITO surface of the film prepared using the conductive paste composition prepared according to the present invention, respectively.
6A to 6C are graphs of sheet resistance, wire resistance, and pattern resistance of films prepared using the conductive paste compositions prepared according to one embodiment of the present invention, respectively.
Figure 7 is a photograph of measuring the pencil hardness of the film prepared using the conductive paste composition prepared according to an embodiment of the present invention.
Figure 8 is a photograph measuring the adhesion of the film prepared using the conductive paste composition prepared according to an embodiment of the present invention.

The present inventors completed the present invention through research on a paste that is used in a transparent electrode of a touch screen panel, in particular, a touch panel, which can be cured at room temperature and has excellent physical properties such as good adhesion to the transparent electrode. Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1. Paste Composition

Screen-printable ultraviolet (UV) curable conductive paste composition according to an aspect of the present invention includes a conductive powder and an ultraviolet curable binder as a whole. At this time, the viscosity of the conductive paste according to the present invention is preferably in the range of 5000 ~ 1,000,000 cps at 50 rpm using a rotary viscometer in consideration of the printing aptitude and workability of screen printing.

end. Conductive powder

The conductive powder in the conductive paste composition according to the present invention may use an inorganic conductive powder that can be used in the display device. The inorganic conductive powder is for imparting conductivity to the electrode paste of a display element such as a touch panel, and for example, one or more metal powders may be used, but any other inorganic powder (for example, conductive carbon) may be used. Ceramic particles such as graphite, carbon black, carbon nanotubes / carbon nanofibers / carbon nanowires), which are based materials, may be added and used.

Preferably, in consideration of cost and conductivity, only silver powder is used alone or in oxidized metal ceramic particles such as zirconium oxide, tin oxide, antimony oxide, nickel oxide, aluminum oxide and indium tin oxide (ITO) in the silver powder. The metallic powder selected can be mixed and used. At this time, the metallic powder that can be used in combination with the silver powder is mixed in a ratio of 1 to 20 parts by weight, preferably 1 to 10 parts by weight based on 100 parts by weight of the silver powder. If the content of the metallic powder mixed with silver powder is less than this, the effect of improving the conductivity is insignificant, and if it is more than this, the resistivity of the film may be too high, and the content of the silver powder is reduced so that the desired effect may not be achieved.

In particular, in connection with the conductive paste composition of the present invention, the silver powder may preferably be a flat flake type, particularly preferably a plate-shaped silver powder having a thickness of 30 to 40 nm and a size of 1 to 5 μm. (1st silver powder) and plate-shaped silver powder (2nd silver powder) which are 70-80 nm in thickness and 1-4 micrometers in size are used preferably mixed. In particular, the above-mentioned first silver powder and second silver powder may be blended in a ratio of 5: 1 to 1: 5, preferably 3: 1 to 1: 3, more preferably 2: 1 to 1: 2. . If the average particle diameter of the silver powder to be used is smaller than the above-mentioned, it is difficult to form irregularities on one surface of the resin layer to which the paste composition is applied, so that the luminance of the pixels is likely to be nonuniform. This is because there is a high possibility that this becomes large and the transparency of the entire touch panel is lowered.

If the shape of the silver powder is not a plate shape but a sphere type, the silver powder of the screen-printed film does not have surface contact with each other and is in point contact with each other, so that a conductive path is difficult to be formed and the required electrical conductivity is not obtained. Because there is. In the case of using a small volume of spherical silver powder in forming a conductive paste based on parts by weight, the silver powder occupies a smaller portion of the total volume of the printed film, resulting in pinholes in the printed conductive pattern. This is because a defect may occur and a problem of low electrical conductivity may occur. In addition, when silver powders having different particle sizes are mixed, it is possible to improve conductivity by making the density uniform by reducing voids between the silver powders. At this time, when using the silver powder of different sizes in the weight ratio outside the above-mentioned range, the effect of filling the voids is reduced, it is particularly preferable to mix the silver powder within the above-mentioned range.

The conductive inorganic powder is included in the paste composition in a proportion of 60 to 80% by weight, preferably 70 to 80% by weight. If the content of the conductive inorganic powder is less than this, it is difficult to achieve the conductivity required in the touch panel, and the luminance nonuniformity of the pixel may be caused, and if it is more than this, transparency may be degraded.

I. bookbinder

A binder that can be cured at room temperature by ultraviolet rays is used to impart the properties of the printed coating film and the fluidity of the paste. The binder constituting the paste composition according to the present invention includes a solid resin in the form of a polyester acrylate oligomer which can be cured by ultraviolet rays, and a diluent solvent for imparting fluidity and other functions of the finally made paste. The binder may affect the physical properties of the prepared paste and the properties of the coating film. The polyester acrylate oligomer according to the present invention is easy to adjust the viscosity, has excellent coating hardness and adhesion, and also has printability. Good.

The solid resin constituting the binder constituting the paste composition according to the present invention preferably uses an ultraviolet curing polyester acrylate oligomer having a glass transition temperature of 5 to 40 ° C. In the case of applying the paste according to the present invention to a touch panel, a screen printing method is preferably used. As a conventional printed object for screen printing, a PET film (polyethylene terephthalate film) is used. Of course, the printed material to which the conductive paste according to the present invention is applied is not limited to PET film, but considering the adhesive force and printability to the printed material, a polyester-based acrylate oligomer having a glass transition temperature in the above-described range is used. This is because it is possible to obtain good printability, and to be suitable as a binder having properties that can be cured by ultraviolet rays.

At this time, as an example of the binder resin is composed of only the resin solid content of the above-described polyester acrylate oligomer (first binder) and / or a resin solid content of a predetermined amount of dilution solvent (binder dilution solvent) is configured in the form (Second binder). In the case of the second binder, the resin solid content: diluent solvent may range from 6: 4 to 8: 2 by weight. In this case, in the case of the first binder not using a diluting solvent, a UV-curable polyester acrylate oligomer (first oligomer) having a glass transition temperature of 5 to 40 ° C., a number average molecular weight of 1000 to 5000, and having 3 to 5 reactors UV curable polyester acrylate oligomer (second oligomer) having a glass transition temperature of 5 to 40 ° C., a number average molecular weight in the range of 3000 to 8000, and 4 to 6 reactors. Can be used. When the molecular weight of the oligomer as a resin solid content satisfies the above-mentioned range, a paste composition having an appropriate viscosity and hardness can be obtained. In this case, the reactor attached to the ultraviolet curable polyester acrylate oligomer may be a reactor that reacts with light, and may be the same reactor as the acrylate ultraviolet curable monomer described later. For example, mono acrylate reactors such as 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, octyldecyl acrylate, isobornyl acrylate, polyethylene glycol diacrylate, neopentyl glycol hydroxypivalate di Acrylate, bisphenol A diacrylate, hexanediol diacrylate, diacrylate reactor such as tetraethylene glycol diacrylate, trimethylolpropane triacrylate, dipentaerythritol triacrylate, pentaerythritol triacrylate, Triacrylate reactors, such as ethoxylated trimethyl-propane triacrylate and trimethyl-propane trisacrylate, tetra, penta hexaacrylate reactors, such as ditrimethylol propane tetraacrylate and dipentaerythritol hexaacrylate, etc. are mentioned. Not , But the invention is not limited to this.

At this time, it is preferable to use a dilution solvent as a liquid component of the binder so that the resin solid content can be cured within 20 seconds in an ultraviolet atmosphere, the boiling point is in the range of 80 ~ 240 ℃. Specifically, terpineol (terpineol), N-methylpyrrolidone (N-methylpyrrolidone, boiling point 202 ℃), butyl cellosolve (boiling point 171.2 ℃), ethylene glycol monobutyl ether acetate (Ethylene glycol monobutyl ether acetate , Boiling point 192 ° C), ethyl carbitol (boiling point 201.9 ° C), ethyl carbitol acetate (boiling point 217.4 ° C), butyl carbitol (boiling point 230.6 ° C), ethoxyethyl acetate (Ethoxyethyl acetate acetate, boiling point 156.3 ° C.), ethyl cellosolve (boiling point 135 ° C.), ethyl cellosolve acetate (ECA), boiling point 156 ° C., butyl acetate (boiling point 126 ° C.), propylene glycol mono Methyl ether (Propylene glycol monomethyl ether, boiling point 121 ℃), propylene glycol monomethyl ether acetate (boiling point 146 ℃), gamma-butyrolactone (γ-butyrolactone, boiling point 204 ℃), me Ketone may be selected from at least one selected from the group consisting of, including (methyl ethyl ketone (MEK), boiling point 80 ℃). Considering the adhesion and printability of the print film to the printed matter, preferably at least one material selected from gamma-butyrolactone, methyl ethyl ketone (MEK) and ethyl cellosolve acetate (ECA), It is more preferable to mix and use these 3 dilution solvents.

In view of the present invention, it is advantageous in terms of printing suitability and other physical properties that the binder is contained in a proportion of 10 to 40% by weight, preferably 20 to 30% by weight in the total paste. In particular, in the case where the above-described binder 1 and binder 2 are mixed, it is preferable to be blended in the paste composition at a ratio of 5 to 20% by weight. For example, when the binder 1 and the binder 2 are mixed, the ultraviolet curable oligomer which is a resin solid may be blended in a proportion of 7 to 30% by weight and 3 to 10% by weight of the binder diluent solvent. If the content of the resin solids is less than this, the viscosity of the conductive paste is low, and if the content of the solids is more than this the contactability is too high, the workability is reduced in the case of screen printing for forming a film for a touch panel.

All. Other additives

On the other hand, the present invention may further include an additive for imparting properties such as conductivity, dispersibility, storage stability, printability to the paste with respect to 100 wt% of the conductive paste. Examples of such additives include: (a) acid additives selected from stearic acid, acetic acid, formic acid phosphoric acid, maronic acid, maleic acid, hydrochloric acid and sulfuric acid; (b) polysiloxane elements selected from dimethylpolysiloxane, methylethylpolysiloxane, diethylpolysiloxane, and the like;

Functionality selected from silicone-based leveling agents selected from foaming agents, silicone diacrylates and silicone polyacrylates, or alcohol-based leveling agents selected from methanol, ethanol, butanol, etc., hexafluoroantimonate, ammonium and inorganic fillers blocked with tritric acid. It is preferable to use an additive made of an additive in view of the characteristics of the conductive paste. However, the present invention is not limited to the above-described additives and may be commercially available in the conductive paste field. At this time, such an additive may be added in a ratio of 0.1 to 3.0% by weight in the paste composition, and when the additive is added in an amount of less than 0.1% by weight, it is difficult to exhibit a desired function. This is because printability may be degraded.

2. Touch panel

The conductive paste composition according to the present invention can be applied to a film for protecting the conductive thin film, for example, on top of a transparent conductive thin film such as ITO constituting the touch panel. This film can be largely divided into a transparent film layer which is made of a transparent material and can be used as a kind of printed material for forming a paste composition, and a resin layer to which the paste composition according to the present invention is applied. The transparent film layer may be glass or plastic, which is transparent and easy to process thinly, preferably a plastic film or a plastic plate. Plastic materials for forming the transparent film layer include a touch such as polyethylene terephthalate (PET), polycarbonate, polymethyl methacrylate, polystyrene, polystyrene / polymetal methacrylate copolymer, triacetyl cellulose resin, cyclic olefin resin, and the like. It is possible to use materials which are well known in the context of panels. Typically, the transparent film layer may be produced in a thickness of 1 ~ 500 ㎛, preferably 1 ~ 300 ㎛.

On the other hand, the resin layer to which the paste composition according to the present invention is applied may be formed to a thickness of about 0.5 to 20 ㎛, preferably 0.5 to 20 ㎛. In order to form the resin layer, a coating method, a gravure printing method, or an offset printing method may be used. Preferably, a silk screen printing method that is free of various curved surfaces is adopted. Preferably after the first printing on the transparent film layer to be printed using the conductive paste according to the present invention, 100 parts by weight of the conductive paste according to the present invention) sulfuric acid, acetic acid, formic acid, phosphoric acid, maronic acid, maleic acid Acid additives selected from the group consisting of hydrochloric acid and stearic acid; Ii) 0.01 to 3.0 parts by weight of an additive comprising a functional additive selected from the group consisting of polysiloxane antifoaming agents, silicone leveling or alcohol leveling agents, hexafluoroantimonate, ammonium blocked with triflic acid and inorganic fillers. Secondary screen printing using the conductive paste can be used. However, the method for forming the film of the touch panel using the conductive paste of the present invention is not limited to the silk screen printing method.

In addition, a transparent conductive thin film may be formed on one surface of the film described above with a thickness of approximately 30 to 3000 m 3. If the thickness is thinner than this, the conductivity is poor. If the thickness is exceeded, irregularities such as patterns formed on one surface of the resin layer may not only affect the uneven structure of the transparent conductive thin film, but may also cause a decrease in transparency. The transparent conductive thin film may be a single or a composite material of an organic material such as polythiophene as well as inorganic materials such as indium tin oxide, indium titanium oxide, tin oxide, and titanium oxide. Since the process of forming the transparent conductive thin film is well known, a detailed description thereof will be omitted.

3. Preparation of Paste

A manufacturing process of the paste will be described with reference to FIG. 1, which schematically illustrates a process for manufacturing a conductive paste composition for a touch panel according to the present invention.

First, the above-mentioned ultraviolet curable polyester acrylate as a solid resin component, and an ultraviolet curable monomer which forms a pattern through the curing reaction at the time of exposure by ultraviolet-ray, The monomer which has one or more functional groups which participate in a curing reaction, , A binder dilution solvent is mixed and defoaming to prepare a binder. At this time, with respect to 100 parts by weight of the paste composition, 7 to 25 parts by weight of the ultraviolet curable polyester acrylate oligomer, 5 to 20 parts by weight of the ultraviolet curable monomer having an acrylate functional group, 3 to 15 parts by weight of the binder dilution solvent. .

At this time, when containing an aromatic as an acrylate monomer, since it may become a problem after exposure, it is not preferable. Specific examples of UV-curable monomers that can be used include 2-hydroxypropyl acrylate (2-Hydroxypropyl acrylate (HPA)), 4-hydroxybutyl acrylate (4-Hydroxybutyl acrylate, 4-HBA), polyethylene glycol diacrylate (Polyethyleneglycol diacrylate, 9EGDA)), neopentylglycol hydroxypivalate diacrylate-modified caprolactone, bisphenol A diacrylate, trimethylolpropane triacrylate triacrylate (TMPTA)), Trimethylolpropane triacrylate modified ethylene oxide, Dipentaerythritol triacrylate, Pentaerythritol tryacrylate (PETA) , Ditrimethylolpropane tetraacrylate (Ditrimethylolpr opane tetraacrylate (DTMPTA)), dipentaerythritol hexaacrylate (DPHA)) or dipentaerythritol hexaacrylate-modified caprolactone, hexanediol diacrylate (Hexanedioldiacrylate, HDDA) ), Octyl decyl acrylate (ODA), trimethylopropane trisacrylate (TMPTA), isobonyl acrylate (IBOA), tetraethyleneglycol dicarylate (TTEGDA) ), Ethoxylated trimethylopropane triacrylate (TM3EOTA) and combinations thereof. Preferably it may be a material selected from HDDA, ODA, TMPTA, IBOA, TTEGDA, DPHA, TM3EOTA and combinations thereof. In particular, considering the compatibility with the above-described oligomer and photocurability, the trifunctional monomer TMPTA, the bifunctional monomer HDDA and the monofunctional monomer ODA can be used alone or in combination. At this time, if two or more monomer combinations are used, for example, they can be used in the same weight ratio.

In particular, the ultraviolet curable monomer may be used in a proportion of 50 to 80 parts by weight, preferably 60 to 80 parts by weight with respect to 100 parts by weight of the polyester-based acrylate oligomer. This is because when the content of the ultraviolet curable monomer is 50 parts by weight or more based on the oligomer, a crosslinked structure is sufficiently formed by the curing reaction of the monomer during exposure, and when the content is 90 parts by weight or less, the content of the binder may be in an appropriate range.

The conductive inorganic powder mentioned above is mixed with the binder thus obtained to obtain a preliminary paste (primary paste) through milling. Since the process of preparing the paste by mixing the binder and the conductive inorganic powder for the conductive paste for screen printing is well known, a detailed description thereof will be omitted.

The final paste (secondary paste) can be obtained by stirring the photocuring initiator dissolved in the paste dilution solvent in the paste thus obtained. The paste dilution solvent may be the same kind as the binder dilution solvent described above, and is, for example, gamma-butyrolactone having excellent dissolving power. The paste solvent serves to control the viscosity, fluidity, printing aptitude, etc. of the finally prepared conductive paste composition, for example, 5 to 40 parts by weight, preferably 100 parts by weight of the conductive paste composition according to the present invention. It may range from 10 to 35 parts by weight. This is because the viscosity of the paste may be excessively high or low when it is out of this range, so that printability may be poor.

On the other hand, the photocuring initiator serves to initiate crosslinking of the acrylate-based monomer. Such photocuring initiators include benzophenone, benzoinbutylether, Esacure EB3,

Chloroacetophenon, such as trichloroacetophenone, diethoxyacetophenone (DEAP), 1-phenyl-2-hydroxy-2-methyl propane-1one (1-phenyl-2-hydroxy-2 -methyl propane-1-one), 1-hydroxycyclohexyl-phenylketone, Irgacure-184 (I-184), 2-hydroxy-2-methyl-1-phenyl-propane Hydroxyacetophenon, 2-benzyl-2- (dimethylamino) -4'- such as -1-one (2-Hydroxy-2-methyl-1-phenyl-propane-1-one, Darocure 173) Morpholino butyrophenone (2-benzyl-2- (dimethylamino) -4'-morpholinobutyrophenone, Irgacure 369 (I-369), alpha-aminoacetophenone (α-Amino Acetophenone, Irgacure-907, I-907), 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone (4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, Irgacure 2959, I-2959 ), 2,2-dimethoxy-1,2-di (phenyl) ethanone (2,2-dimethoxy-1,2-di (phenyl) ethanon, Irgacure 641, I-651), bis (h5-2, 4, -cyclo Tadien-1-yl) bis [2,6-difluoro-3- (1H-pyrrol-1-yl) phenyltitanium (bis (h5-2,4-cyclopentadien-1-yl) bis [2,6 -difluoro-3- (1H-pyrrol-1-yl) phenyl] -titanium, Irgacure-784 (I-784), bis (2,4,6-trimethylbenzoyl) -phenylphosphineoxide (Bis (2,4 , 6-trimethylbenzoyl) -phenylphosphineoxide, Irgacure-819 (I-819)), 2-methyl-1- [4-methylthio] phenyl-2-morpholinopropan-1-one (2-methyl-1 [4 -methylthio] phenyl-2-morphorinopropane-1-on), 2,3,6-trimethylbenzoyl phenyl ethoxyphosphine oxide (2,3,6-Trimethylbenzoyl phenyl ethoxyphosphine oxide (TPO)), 2,4-diethyl 2,4-Diethylthioxthanthone (DETX), Isopropyl thioxthanthone (ITX), oligo [2-hydroxy-2-methyl-1- [4- (1-methylbityl) phenyl ] Propanone] (Oligo [2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone, Esacure KIP150), or a combination thereof. In consideration of the wavelength region of the light source used in the UV curing process to be described later, an appropriate photocuring initiator of the active wavelength region may be selected. For example, when the wavelength region of the UV lamp light source used for curing is 200 to 400 nm, Irpocure-819, which has excellent light absorption ability in the vicinity, and a pattern printed with UV curable paste, has a high proportion of conductive inorganic powder, which makes TPO (2,3,6) having an absorption region of a long wavelength region, considering that internal purification is difficult. -trimethylbenzoyl diphenylphosphine oxide) can be used for paste dilution solvents with excellent solubility. At this time, the content of the photocuring initiator may be 1 to 10 parts by weight, preferably 2 to 8 parts by weight based on 100 parts by weight of the inorganic conductive powder in the conductive paste composition. This is because the photocuring reaction is effectively initiated when the content of the photopolymerization initiator is 1 part by weight or more with respect to 100 parts by weight of the inorganic conductive powder to form a network structure, and even if the amount exceeds 10 parts by weight, the desired effect does not increase proportionally. At this time, a small amount of the curing agent separately from the photocuring initiator, for example, 0.1 to 5 parts by weight based on 100 parts by weight of the inorganic conductive powder may be used.

Hereinafter, the present invention will be described through Examples, but the present invention is not limited to these Examples.

Properties of Conductive Powders and Oligomers

The basic physical properties of silver powder, which is one of the conductive inorganic powders, which are the main components of the paste composition of the present invention, and polyester acrylate oligomer (binder), which is a resin solid, are as follows.

Properties of Silver Powder, a Conductive Powder Silver powder Thickness (nm) Size (μm) shape One 30 to 40 1 to 5 Plate type 2 70-80 1-4 Plate type

Physical Properties of Resin Solids (Oligomers) Oligomer Glass transition temperature (캜) Number average molecular weight Number of reactors One 5 to 40 1000 to 5000 3 to 5 2 5 to 40 3000 to 8000 4 to 6

Example 1 Preparation of Conductive Paste

A conductive paste composition was prepared by combining each component according to the procedure shown in FIG. 1. Table 3 shows the content ratio of each component used to prepare the conductive paste according to the type and content of the monomer in the binder component. In Table 3, silver powder-1 is M13 silver powder of Tokusen, Japan, silver powder-2 is 022END silver powder of Heesung Electronics in Korea, and tin oxide (SnO ₂ ) powder used as a conductive additive is a product of Japan Junsei Co., Ltd. Polyester resin-1 was synthesized by KCI, and polyester resin-2 was product name ISA-210E, which was commissioned by Ilsam resin. Each monomer was synthesized by SK-cyteck. As solvents, ECA (ethyl solosolve acetate) was Samcheon Chemical, MEK (methyl ethyl ketone) was SK-chemical, and gamma butyrolactone was manufactured by Junsei. Each component is expressed in parts by weight (phr). Monomers used in pastes 1-8 were TMPTA (trimethylolpropane triacrylate), HDDA (hexanedioldiacrylate), ODA (octyldecylacrylate), IBOA (isobonyl acrylate), TMPTA + ODA mixed, HDDA + ODA mix, IBOA + ODA mix, IBOA + HDDA mix.

A binder was prepared by pre-mixing a UV-curable polyester resin with a mixed solvent of butyrolactone and methyl ethyl ketone (MEK) as a resin solvent. A paste of powder was added and stirred, followed by dispersing the metal powder using a 3-roll mill (TRM-6.5, a light machine) 2,3,6-trimethylbenzoyl phenyl ethoxyphosphate as a photocuring initiator in the dispersed liquid. A conductive paste was prepared by adding fin oxide (TPO) and I-184.

Conductive Paste Manufacturing Ingredient Content paste Inorganic powder bookbinder
solvent Photoinitiator solution silver
Powder 1 silver
Powder 2 SnO ₂
powder poly
ester-1 poly
ester-2 Monomer solvent I-184 TPO One 36 36 5 7 5 5 4.5 0.5 0.5 0.5 2 36 36 5 7 5 5 4.5 0.5 0.5 0.5 3 36 36 5 7 5 5 4.5 0.5 0.5 0.5 4 36 36 5 7 5 5 4.5 0.5 0.5 0.5 5 36 36 5 7 5 5 4.5 0.5 0.5 0.5 6 36 36 5 7 5 5 4.5 0.5 0.5 0.5 7 36 36 5 7 5 5 4.5 0.5 0.5 0.5 8 36 36 5 7 5 5 4.5 0.5 0.5 0.5

Example 2: Screen Printing

The conductive paste prepared in Example 1 was printed on an ITO film using a screen printing method. As a 250 mesh and 450 mesh SUS material, patterning was carried out using a screen printing machine (BS-150ATC) using a pattern (100 μm, 60 mm) and a 320 × 320 mm screen plate with a front surface (45 × 45 mm), and 120 ° C. UV curing was performed after the preheating process to evaporate the solvent for 20 seconds. Plate making specifications, printing conditions and UV curing conditions used for printing are shown in Tables 4-6, respectively. Pattern printing was performed for the line resistance, and front printing was performed for the sheet resistance and the non-constant.

Specification of screen board Mesh
count Mesh
Angle (°) Tension (mm / kgf) Mesh thickness (㎛) Emulsion
Thickness (㎛) all
Thickness (㎛) X Y SUS 400 34 0.80 0.80 39 15 54 SUS 250 22.5 59 10 69

Printing condition value contact off gap
(Mm) squeegee angle
(°) squeegee
speed (mm / sec) print
pressure (Kgf / ㎠) pattern 2.5 80 100 6 Front 2.5 80 34 6

UV curing conditions Type belt speed (m / s) Light quantity (J / cm ² ) Temperature (℃) time (1 / sec) UV curing system 1.6 1000 80 35

Experimental Example 1 Rheological Measurement of Paste

The rheology of the screen printed conductive paste was measured using a HANKE Phesoscope. Measurement conditions were 25 degreeC and shear rate (100 1 / s).

Figure 2 is a graph showing the results of measuring the viscosity according to the shear rate among the rheological properties according to this embodiment and the measurement results are shown together in Table 7 below. Looking at the viscosity characteristics of the prepared conductive paste composition according to the shear rate, it can be seen that the viscosity decreases from the low shear rate to the high shear rate.

Viscosity of Paste According to Shear Rate Viscosity Rheometer (cps) paste 1 paste 2 paste 3 paste 4 paste 5 paste 6 paste 7 paste 8 1 1 / s 93510 150700 200700 284900 153300 131800 117600 104500 5 1 / s 51330 41820 51220 120200 43010 38300 29780 24950 10 1 / s 30490 24090 30460 66030 25100 22290 17670 15290 50 1 / s 18977 17677 18892 21050 17656 17049 16145 15525 100 1 / s 8422 9932 8680 8154 9222 8397 9124 9997 TI (1/10) 3.06 6.25 6.58 4.34 6.01 5.91 5.27 6.83 TI (1/100) 11.10 15.17 23.12 34.93 1.66 15.69 12.88 10.45

Experimental Example 2 Measurement of Electrical Conductivity of Paste

In order to measure the conductivity for the electrode pattern prepared in Example 2, the electrode printed with paste was dried at 130 ° C. for 2 minutes and measured in a light amount state of 3000 mj / cm. The electrical conductivity of the conductive paste electrode obtained in Example 2 was measured by measuring the surface resistance of the surface of the electrode pattern according to the method of 4 probe method (4 prove, KS L 1619) that measured the surface resistance meter (2002 multimeter, keithley) After measuring the thickness with the thickness gauge, it was converted into a specific resistance. On the other hand, the electrical conductivity of the electrode pattern formed to measure the line resistance was measured by the two probe method (2 prove) after measuring the surface of the electrode pattern with the same surface resistance meter. Surface resistance measurement results are shown in FIG. 3 and wire resistance measurement results are shown in FIG. 4.

Experimental Example 3 Sharpness Measurement

The sharpness of the film ITO surface prepared in Example 2 was measured. The sharpness measurement results for the films made using each paste are shown in FIGS. 5A-5H.

Experimental Example 4 Electrical Characteristics of Paste 4

As a result of Experimental Examples 1 to 3, Paste 4 was the best among the pastes 1 to 8 in terms of rheology (flow characteristic), printability and electrical properties of the post-printing coating. Thus, an additional experiment was conducted with respect to paste # 4. In this example, in order to measure the conductivity of the electrode pattern using the composition of paste 4 in the electrode pattern prepared in Example 2, the electrode printed with the paste is dried at 130 ℃ for 2 minutes, 3000 mj / cm It measured in the light quantity state. The electrical conductivity of the conductive paste electrode obtained in Example 2 was measured by measuring the surface resistance of the surface of the electrode pattern according to the method of 4 probe method (4 prove, KS L 1619) that measured the surface resistance meter (2002 multimeter, keithley) After measuring the thickness with the thickness gauge, it was converted into a specific resistance.

On the other hand, the electrical conductivity of the electrode pattern formed to measure the line resistance was measured by the two probe method (2 prove) after measuring the surface of the electrode pattern with the same surface resistance meter. Surface resistance measurement results are shown in FIG. 6A, wire resistance measurement results in FIG. 6B, and pattern resistance measurement results in FIG. 6C, respectively. In the 250 mesh, the surface resistance is 1.5 to 3 mΩ, the specific resistance is 250 × 10 ^-5 or less in the 250 mesh, and the wire resistance is 25 to 30 에서 in the 400 mesh. It was.

Experimental Example 5: Hardness Measurement

The hardness of the film using the composition of paste 4 was measured. In order to measure the hardness of the paste coating film, the following method was followed. First, in the case of paint and varnish, it measured based on KS M ISO15184 which is a pencil hardness measurement method of a coating film. Pencil hardness means pencil hardness that is a pencil lead having a prescribed size and shape and a prescribed hardness. According to the present Example, it measured in the state which dried at 130 degreeC for 2 minutes at the light amount 1500 (mj / cm <2>). The results are shown in FIG. 7, with pencil strength of 5H indicating good hardness.

Experimental Example 6: Measurement of the adhesiveness (adhesive force) of the paste

The adhesive test method of paste paint using paste 4 was measured according to KS M ISO 2409. To this end, the printed coating film was cross-cut in a cross shape and then attached with a cellophane tape, and then it was determined whether or not the printed pattern cells were good as falling numbers. Adhesion measurement results are shown in Figure 8, as shown, the paste prepared according to the present invention was excellent in adhesion.

Claims (10)

60 to 80 wt% of conductive inorganic powder; A first binder composed of an ultraviolet curable polyester acrylate oligomer having a number average molecular weight in the range of 1000 to 5000 and having 3 to 5 reactors, and a glass transition temperature. 2nd binder containing 60-80 weight part of resin solids which are 5-40 degreeC, the number average molecular weights 3000-8000, and the ultraviolet-curable polyester acrylate oligomer which has 4-6 reactors, and 20-40 weight part of dilution solvents 20 to 40% by weight of an ultraviolet curable binder containing a resin solid content of the polyester acrylate oligomer consisting of;
Conductive paste composition for a touch panel comprising.
delete The conductive paste composition for a touch panel according to claim 1, wherein 5 to 20 parts by weight of the first binder and 5 to 20 parts by weight of the second binder are blended with respect to 100 parts by weight of the conductive paste composition for the touch panel. The method of claim 1, wherein the conductive inorganic powder comprises a silver powder, the silver powder is a plate-like silver powder having a thickness of 30 to 40 nm and a size of 1 to 5 ㎛, and a thickness of 70 to 80 nm and size 1 A conductive paste composition for a touch panel, characterized by mixing a plate-like silver powder of ~ 4 ㎛.
The conductive film for touch panels containing the conductive paste composition as described in any one of Claims 1, 3, and 4.
A touch panel comprising a transparent conductive thin film coated by the conductive film for touch panel according to claim 5.
As a method of manufacturing a conductive paste for a touch panel,
(a) 7 to 25 parts by weight of an ultraviolet curable polyester acrylate oligomer, 5 to 20 parts by weight of a monomer having an acrylate functional group, and 3 to 15 parts by weight of a binder dilution solvent based on 100 parts by weight of the conductive paste for a touch panel. Preparing a binder;
(b) adding 60 to 80 parts by weight of the conductive inorganic powder to 100 parts by weight of the conductive paste composition for the touch panel to the obtained binder, followed by stirring the mixture to obtain a first paste; And
(c) dissolving a photocuring initiator in a paste dilution solvent, followed by stirring with the first paste to obtain a second paste.
According to claim 7, wherein the monomer is 2-hydroxypropyl acrylate (2-Hydroxypropyl acrylate (HPA)), 4-hydroxybutyl acrylate (4-Hydroxybutyl acrylate (4-HBA)), polyethylene glycol diacrylate (Polyethyleneglycol diacrylate, 9EGDA)), neopentylglycol hydroxypivalate diacrylate-modified caprolactone, bisphenol A diacrylate, trimethylolpropane triacrylate triacrylate (TMPTA)), Trimethylolpropane triacrylate modified ethylene oxide, Dipentaerythritol triacrylate, Pentaerythritol tryacrylate (PETA) , Ditrimethylolpropane tetraacrylate (DTMPT A)), dipentaerythritol hexaacrylate (DPHA)) or dipentaerythritol hexaacrylate modified caprolactone, hexanediol diacrylate (Hexanedioldiacrylate (HDDA), octyl Octyl decyl acrylate (ODA), trimethylopropane trisacrylate (TMPTA), isobonyl acrylate (IBOA), tetraethyleneglycol dicarylate (TTEGDA), ethoxylate A method for producing a conductive paste for a touch panel, characterized in that the material is selected from the group consisting of Shitylated trimethylopropane triacrylate (TM3EOTA) and combinations thereof.
The method of claim 7, wherein the binder dilution solvent and the paste dilution solvent terpineol (terpineol), N-methylpyrrolidone (N-methylpyrrolidone), butyl cellosolve (butyl cellosolve), ethylene glycol monobutyl ether acetate (Ethylene glycol monobutyl ether acetate, ethyl carbitol, ethyl cabitol acetate, butyl carbitol, ethoxyethyl acetate, ethyl cellosolve, ethyl Ethyl cellosolve acetate, butyl acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, gamma-butyrolactone (γ- butyrolactone), methyl ethyl ketone (methyl ethyl ketone) and a combination of the conductive paste for the touch panel, characterized in that the material selected from Manufacturing method.
The method of claim 7, wherein the photocuring initiator is benzophenone (Benzophenone); Chloroacetophenon, including trichloroacetophenone; Diethoxy acetophenone (DEAP); 1-phenyl-2-hydroxy-2-methyl propane-1one (1-phenyl-2-hydroxy-2-methyl propane-1-one); 1-Hydroxycyclohexyl-phenylketone, 2-hydroxy-2-methyl-1-phenyl-1-propan-1-one (2-Hydroxy-2-methyl-1-phenyl hydroxyacetophenon, including -propane-1-on; 2-benzyl-2- (dimethylamino) -4'-morpholinobutyrophenone); 2-benzyl-2- (dimethylamino) -4'-morpholinobutyrophenone; Alpha-aminoacetophenone; Bis (h5-2,4, -cyclopentadien-1-yl) bis [2,6-difluoro-3- (1H-pyrrol-1-yl) phenyltitanium (bis (h5-2,4-cyclopentadien -1-yl) bis [2,6-difluoro-3- (1H-pyrrol-1-yl) phenyl] -titanium); Bis (2,4,6-trimethylbenzoyl) -phenylphosphineoxide (Bis (2,4,6-trimethylbenzoyl) -phenylphosphineoxide), 2-methyl-1- [4-methylthio] phenyl-2-morpholino Propane-1-one (2-methyl-1 [4-methylthio] phenyl-2-morphorinopropane-1-on), 2,3,6-trimethylbenzoyl phenyl ethoxyphosphine oxide (2,3,6-Trimethylbenzoyl phenyl Preparation of a conductive paste for a touch panel, characterized in that the material selected from ethoxyphosphine oxide, 2,4-diethylthioxanthone, isopropyl thioxthanthone or a combination thereof Way.

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