KR101024994B1 - Binder sol - Google Patents

Abstract

The present invention relates to a binder sol, a binder formed by adding a network modification material containing at least one ion of Li ⁺ , Na ⁺ , K ⁺ , Mg ^{2 +} , Pb ^{2 +} , Ca ^{2 +} to a water dispersed colloidal silica Make sol a technical point. Accordingly, there is an advantage that can be used as a binder at a high temperature by adding a network modifier to the colloidal silica that is present in the liquid phase at room temperature.

Modified Oxide Binder Sol Network

Description

Binder sol

The present invention relates to a binder sol, and to a binder sol that can be used as a binder at a high temperature by adding a network modifier or the like to colloidal silica present in the liquid phase at room temperature, and a method for manufacturing the same.

In general, binder materials used are mostly organic materials for improving adhesion. However, when the temperature rises, carbonization occurs and the adhesion decreases. Therefore, the heat resistant binder for use at high temperature should be composed of a heat resistant inorganic material excluding the organic material from which carbonization occurs.

The heat resistant binder can be made using glass composition among these inorganic materials.

The most representative material for forming glass in glass composition is SiO ₂ . Unlike SiO ₂ , which is a glass-forming material, glass alone does not form glass, but when mixed with SiO ₂ , which is a glass-forming material, in proper proportion, glass is formed, and there is a modified oxide that can give proper properties to the glass. .

Representative modified oxides include Li ₂ O, Na ₂ O, K ₂ O, MgO, PbO and CaO.

The structure of glass made only of SiO ₂ is located around the Si atom, where the O atom corresponds to the vertex of the tetrahedron. In this form, when the tetrahedron of SiO ₂ is connected by sharing one oxygen, the oxygen is called crosslinked oxygen, and the connection that directly bonds between Si ions by oxygen atom is called oxygen bridge.

When a modified oxide is added thereto, the ions of the modified oxide cut an oxygen bridge to electrostatically bond with one oxygen. In this case, one of the oxygen is connected to the Si cation, which is a glass forming material, and one is connected to the modified cation. As such, an oxygen atom that binds to only one Si atom, that is, unbridged oxygen, is generated, and the glass structure is gradually weakened.

In this way, when the amount of modified oxide is gradually increased, the number of non-crosslinked oxygen atoms increases and the glass structure becomes open. This means a weakening of the structure, which leads to a decrease in melting temperature as the viscosity decreases. Since the glass structure is destroyed by the increase of the non-crosslinked oxygen in the amount of the modified oxide, there is a limit to maintain the glass state.

When the common glass is placed on a substrate of any metal or ceramic and the temperature is raised, the glass melts and adheres well to the substrate. By using this phenomenon, the glass composition is melted at a high temperature and cooled to form a powder or flakes called glass frit. Glass frit is widely used for protective coating or sealing, and melting temperature also varies depending on the composition. The glass frit exists in the form of a solid at room temperature, and is heated to a liquid state to be bonded, and then cooled again to be bonded in the form of a solid.

As described above, various techniques have been introduced in connection with a paste using glass.

For example, a nonmetallic terminal electrode of a multilayer ceramic capacitor using a non-reducing glass, such as barium borate glass, zinc barium borate glass, zinc barium borosilicate glass (see US Patent No. 3,902,102) or the like is known. And using a copper paste for terminal electrodes with barium borosilicate glass (see Japanese Patent Publication No. 5-234415), or having a zinc borosilicate glass having a specific composition containing an alkali metal component and an alkaline earth metal component. Using copper paste for one terminal electrode (see Japanese Patent Publication No. 59-184511), using strontium borosilicate glass for terminal electrodes (see Japanese Patent Publication No. 9-55118), and no lead Conductor paste (see Korean Patent Application Laid-Open No. 2003-52996) is known.

In addition, an ultra low loss glass (see Korean Patent Application Laid-Open No. 2000-23743) containing at least one kind of network modified oxide in silica glass is known.

The conventional techniques are difficult to handle because of the use of the solid glass and problems with mixing with other materials, such as coating at room temperature is not possible, and after melting the glass to coat the melted glass to another material Even if there is a problem such as difficult to adjust the thickness.

Accordingly, the present invention has been made to solve the above problems of the prior art, and an object of the present invention is to provide a binder sol that can be used as a binder at a high temperature by adding a network modification material to the colloidal silica that is present in the liquid phase at room temperature. do.

The present invention for achieving the above object, by adding a network modified material containing at least one ion of Li ⁺ , Na ⁺ , K ⁺ , Mg ^{2 +} , Pb ^{2 +} , Ca ^{2 +} to the water dispersed colloidal silica The binder sol formed is a technical subject matter.

The present invention also relates to a binder sol formed by adding at least one network modification material of LiOH, NaOH, KOH, Mg (OH) ₂ , Ca (OH) ₂ to the water dispersed colloidal silica.

Here, the network modification material is an aqueous solution, it is preferable that the network modification material contains 0.01 to 2 mol per mol of SiO ₂ which is a solid content in colloidal silica.

In addition, it is preferable that an inorganic powder is further added to the binder sol, the inorganic powder is an electrical insulating material, and the inorganic powder is alumina, silica or magnesia.

In addition, the binder sol is further added to one or more infrared emitter materials of jade, cerite, cordierite, germanium, iron oxide, mica, manganese dioxide, silicon carbide, gansumite, carbon, the binder sol to which the infrared emitter material is added It is preferably coated on the upper surface of the substrate to generate heat and used for an infrared heating device or the like.

On the other hand, the binder sol is further added in the form of a fibrous material, the fibrous material is glass fiber, alumina fiber, SiC fiber, Si ₃ N ₄ fiber, carbon fiber, silicate fiber, silica fiber, boron fiber, PAN fiber , At least one of carbon nanotubes, BN nanotubes, Si nanowires, SiCO fibers, Si-CNO fibers, SiC nanotubes, and SiC nanowires.

As described above, the present invention has the effect that the binder sol using the colloidal silica as a starting material is very convenient to use as a binder because it exists in a liquid state at room temperature.

Since it exists in a liquid state, this material itself synthesized with a binder sol can be coated on a substrate and used as a functional film such as an insulating film.

By adding a heat resistant inorganic material, heat resistance may be increased, and the thermal expansion coefficient may be adjusted to prevent defects such as cracks due to the difference in thermal expansion coefficient between the coating film and the substrate at a high temperature.

Since the heat resistance is very excellent, when the inorganic sol powder having high infrared emissivity is added to the binder sol and coated on the heating plate, it can be used for a high efficiency infrared heating device.

Since the coated surface is glassy, the surface is smooth and the adhesive force is excellent, so that it can be used in a food material heating device such as a microwave oven.

Since the surface is smooth and excellent adhesion does not generate dust, it can be used for heating devices of high-tech industries such as clean rooms and semiconductor lines.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiments of the present invention do not limit the present invention, and it will be apparent that the rights of the present invention extend to the embodiments in which the present invention can be implemented.

A feature of the present invention is to use colloidal silica (colloidal silica) as a starting material, the colloidal silica is present in the liquid phase at room temperature.

Colloidal silica is a form of very fine (typically 100 μm or less) SiO ₂ dissolved in water. When the network modifier is added to the colloidal silica, it exists as a liquid at room temperature, but hydrolysis occurs as the temperature rises, and the gel changes to a glass phase.

If the amount of the network modifier added to the colloidal silica is less or more than an appropriate amount, the glass phase is not well formed. In addition, even if the glass phase is formed, the heat resistance temperature of the glass phase formed decreases as the amount of the network modifier added, and the heat resistance temperature increases as the amount added, so controlling the amount of the network modifier well can be used for various purposes. There is this.

1 is a conceptual diagram illustrating a process of synthesizing a binder sol by adding an aqueous KOH solution to colloidal silica.

As such, the binder sol using the colloidal silica as a starting material exists in a liquid state at room temperature, which is very convenient to use as a binder, and there is an advantage in that a functional film can be made by adding a powder to impart functionality thereto.

Hereinafter, embodiments of the present invention will be described.

<First Embodiment>

First, a silica sol solution was prepared by diluting 104.7 g of colloidal silica (Ludox HS-40) having a 40% silica solid content and 70 g of distilled water at a speed of 500 rpm using a magnetic bar and a stirrer.

In another beaker, 20 g of potassium hydroxide (KOH) was dissolved in 40 g of distilled water using a magnetic bar and a stirrer (500 rpm, 30 minutes) to prepare a KOH solution.

The prepared silica sol solution and KOH solution were reacted by using a magnetic bar and a stirrer (700rpm) until the temperature of the solution rose to 80 ° C under water bath conditions, and gradually cooled to room temperature when the temperature of the solution reached 80 ° C. To prepare a sol.

The thermal analysis of the binder sol prepared in Example 1 is shown in FIG. 2.

As a result of analysis of FIG. 2, the pyrolysis temperature of the prepared binder sol was found to be 1000 ° C. or higher.

Second Embodiment

In a second embodiment of the present invention, 100 g of the binder sol synthesized in the first embodiment is infrared radiation powder, SiC 20g, jade 10g, cerite 10g, mica 9g, MnO ₂ and C (carbon) 0.5g each mixed by The binder sol and spinning powder were dispersed by ball milling for 6 hours.

The dispersed sol was coated on a substrate by spray coating to prepare an emissivity test specimen.

As in the second embodiment, the emissivity of the coating film measured after coating a stainless steel substrate by adding a high efficiency infrared radiation powder to the binder sol is shown in FIG.

As shown in FIG. 3, the emissivity was found to be 89.8% at 300 ° C., which was very excellent.

In addition, an electrically insulating inorganic powder such as alumina, silica or magnesia may be added to the binder sol synthesized in the first embodiment, and then used as an insulating coating film.

Further, if necessary, glass binder, alumina fiber, SiC fiber, Si ₃ N ₄ fiber, carbon fiber, silicate fiber, silica fiber, boron fiber, PAN fiber, carbon nanotube in the binder sol synthesized in the first embodiment When BN nanotubes, Si nanowires, SiCO fibers, Si-CNO fibers, SiC nanotubes, and SiC nanowires are added to form a coating film, the strength and toughness of the coating film are increased. In the case of carbon nanotubes, there is an advantage that the electrical conductivity can be increased.

1 is a diagram showing the concept of a process for synthesizing a binder sol by putting a KOH aqueous solution in the colloidal silica according to the present invention.

2 is a diagram showing the results of thermal analysis of the binder prepared in Example 1 of the present invention.

3 is a view showing the emissivity of the coating film according to a second embodiment of the present invention.

Claims (12)

To the water dispersed colloidal silica, a network modification material containing at least one of Li ⁺ , Na ⁺ , K ⁺ , Mg ²⁺ , Pb ²⁺ and Ca ²⁺ is added to form a mixture, which is a solution under water bath conditions. Binder sol, characterized in that formed by reacting the mixture by raising the temperature of to 80 ℃. The binder sol of claim 1, wherein the network modification material is an aqueous solution. One or more network modified materials of LiOH, NaOH, KOH, Mg (OH) ₂ and Ca (OH) ₂ were added to the water dispersed colloidal silica to form a mixture, which was then heated to 80 ° C. under water bath conditions. Formed by reacting the mixture. The binder sol of claim 3, wherein the network modification material is an aqueous solution. The binder sol according to any one of claims 1 to 4, wherein the network modification material contains 0.01 to 2 mol per mol of SiO ₂ which is a solid content in colloidal silica. The binder sol according to any one of claims 1 to 4, wherein an inorganic powder is further added to the binder sol. The binder sol of claim 6, wherein the inorganic powder is an electrically insulating material. The binder sol according to claim 7, wherein the inorganic powder is alumina, silica or magnesia. 5. The infrared ray emitter material of claim 1, wherein the binder sol further comprises at least one infrared emitter material of jade, cercite, cordierite, germanium, iron oxide, mica, manganese dioxide, silicon carbide, macsumite, and carbon. Binder sol, characterized in that the addition. 10. The binder sol of claim 9, wherein the binder sol to which the infrared emitter material is added is coated on the substrate to generate heat. The binder sol according to any one of claims 1 to 4, wherein the binder sol further comprises a fibrous material. The method of claim 11, wherein the fibrous material is glass fiber, alumina fiber, SiC fiber, Si ₃ N ₄ fiber, carbon fiber, silicate fiber, silica fiber, boron fiber, PAN fiber, carbon nanotubes, BN nanotubes, A binder sol characterized by being at least one of Si nanowires, SiCO fibers, Si-CNO fibers, SiC nanotubes, and SiC nanowires.

Images