KR101408135B1 - Manufacturing method of green sheet, ceramic slurry for manufacturing green sheet, and green sheet with high dencity and toughness - Google Patents

Abstract

The present invention relates to a method for producing a green sheet and a ceramic slurry for preparing a green sheet, which comprises a first mixing step for mixing a dispersion solvent and a dispersant to prepare a dispersion solution, a binder and a plasticizer mixed with the dispersion solution to prepare a one- A third mixing step of mixing the ceramic powder and the one-component solution to prepare a ceramic slurry; applying the ceramic slurry on a substrate to form a ceramic slurry; And a film forming step of producing a green sheet. The green sheet provides a high-density ceramic green sheet having good bonding properties between ceramic particles, good plasticity and peelability from the base film, excellent dispersibility of raw material powder, and excellent surface properties without irregularities, cracks and wrinkles .

Description

TECHNICAL FIELD [0001] The present invention relates to a method for producing a green sheet having high density and high strength, a ceramic slurry for producing a green sheet, and a green sheet,

The present invention relates to a method for producing a green sheet having high density and high strength, and a method for producing a green sheet having excellent peelability, excellent surface properties without irregularities, cracks and wrinkles, A ceramic slurry used for the production of a green sheet, and a green sheet.

The green sheet is formed by a method such as screen printing, roll-to-roll or the like using a metal paste or various special inks (conductive, semiconductive, dielectric, etc.). Such a green sheet can be utilized in the manufacture of various electronic products by forming a circuit pattern through a printing process and co-firing one or several layers of the sheets thus formed. 2. Description of the Related Art In recent years, electronic products have become lighter, smaller, and thinner, and the frequency with which such thin sheets of green sheets are utilized in the production process of various circuit boards, capacitors, ceramic capacitors, fuel cells and the like is increasing.

Generally, a ceramic green sheet is produced by mixing a polycrystalline ceramic powder and other additives such as a solvent, a polymer type binder, a plasticizer and a defoaming agent in a proper ratio, a defoaming step of removing bubbles in the slurry generated during mixing, The defoated slurry is thinly coated on a support film such as a Mylar film using a Dr. Blade to form a thin sheet, followed by drying in the sequential order of drying the intervening solvent in the sheet Has come. That is, the green sheet is manufactured by coating a slurry on a base film to coat the base film, separating the base film, and stacking the electrode layers formed with the electrode patterns, crossing each other.

However, in recent years, as a demand for miniaturization and high functionality of electronic parts has led to a demand for thinning of green sheets and high layer thicknesses, it is necessary to form green sheets to thicknesses of several micrometers as much as possible. At this time, in order to produce a thin green sheet by a tape casting method using a doctor blade, the viscosity of the slurry to be cast is very important. When the viscosity of the slurry is low, it is difficult to maintain the shape of the coated slurry and the sheet thickness may become uneven, and since the strength of the green sheet is low, it tends to be broken easily when it is detached from the base film, .

Therefore, in order to prevent breakage of the green sheet during the laminating process, the total amount of the polymer used as the binder is increased as much as possible. When a binder having a high molecular weight is used, the viscosity of the slurry becomes high, And it is difficult to form a green sheet. In addition, the solubility of the binder polymer in the solvent is decreased, and uneven polymer particles remain on the surface and in the interior of the green sheet, which causes a failure during the lamination process and firing.

US Patent No. 5,268,415 relating to the production of a green sheet discloses a method for producing a green sheet in the form of a thin film by forming an extruded film by mixing a ceramic powder with polyolefins and stretching the same. However, due to the high elastic modulus of the stretched polymer resin and the non-polar nature of the olefin, the green sheet thus produced has poor mutual bonding with the ceramic powder, has low interlayer adhesion at the time of lamination and compression, Or the like, there arises a problem that it is difficult to produce an electronic device due to the occurrence of de-lamination or cracks between the ceramic green sheet layers. In addition, US Patent No. 4,496,506 discloses a method for producing a green sheet using polyvinyl alcohol. However, due to the weak nature of polyvinyl alcohol, the green sheet thus produced is not only difficult to form, but also difficult to produce with a thin film of several 탆 thick.

Korean Patent No. 1995-0040878 discloses a ceramic powder in which a mixed solvent of ethanol and MEK (methyl ethyl ketone) is used, and polyvinyl butyral (PVB), polyethylene glycol (PEG), dibutyl phthalate Is added to produce a high-density excellent green sheet. However, the slurry is manufactured by performing the primary ball mill for mixing the solvent and the ceramic powder for 20 hours or more, and then performing the secondary ball mill for adding and mixing the organic additive for 20 hours or longer. And a drying time of 3 days at room temperature after tape-casting is required, so that the production time of the green sheet is very long.

An object of the present invention is to produce a green sheet having excellent surface properties, high strength and high toughness. The green sheet has excellent desorption properties from a substrate and has excellent surface properties without irregularities, cracks, and wrinkles. Another object of the present invention is to provide a green sheet comprising a ceramic sheet having excellent lamination properties and interlayer adhesion, high density, and high strength even after firing.

In order to achieve the above object, a method of manufacturing a green sheet according to an embodiment of the present invention includes: a first mixing step of mixing a dispersion solvent and a dispersant to prepare a dispersion solution; A second mixing step of mixing a binder and a plasticizer with the dispersion solution to prepare a one-component solution; A third mixing step of mixing the ceramic powder and the one-component solution to prepare a ceramic slurry; And a film forming step of coating the ceramic slurry on a base material and drying the green sheet to produce a green sheet including a ceramic sheet.

The dispersion solvent may be at least one selected from the group consisting of methanol, ethanol, isopropyl alcohol, toluene, methyl ethyl ketone (MEK), diethyl ether, and trichlorethylene trichloroethylene), and mixtures thereof.

The dispersing agent may be selected from the group consisting of fish oil, polyethylene glycol (PEG), alcohol polyoxyethylene ether (AE), monoglyceride, sorbitan ester, nonionic surface active agent and combinations thereof Based dispersant selected from the group consisting of

The binder may be selected from the group consisting of cellulose, polyvinyl butyral (PVB), polymethyl methacrylate (PMMA), polyacryl esters, and combinations thereof. And may include any one of them.

Examples of the plasticizer include butyl benzyl phthalate (BBP), dibutyl phthalate (DBP), di-octyl phthalate (DOP), di-octyl-adipate (DOA) And a combination of these.

The ceramic powder may have an average particle diameter of 100 nm or less.

The ceramic slurry may contain 24 to 36 parts by weight of a dispersion solvent, 2 to 4 parts by weight of a binder, 2 to 4 parts by weight of a plasticizer and 2 to 4 parts by weight of a dispersant based on 100 parts by weight of ceramic powder.

The dispersion solvent may be a mixture of a first dispersion solvent and a second dispersion solvent which are two different dispersion solvents and at least one of the first dispersion solvent and the second separation solvent is an alcohol, , And the first dispersion solvent and the second dispersion solvent at a weight ratio of 1: 0.6 to 1.5.

The dispersion solvent may include toluene and an alcohol.

The mixing in the first mixing step may be performed for 1 to 2 hours.

The mixing in the second mixing step may be performed for 2 to 3 hours.

The mixing in the third mixing step may be performed for 20 to 28 hours, and may include ball milling.

In another embodiment of the present invention, the ceramic slurry for preparing a green sheet comprises 100 parts by weight of ceramic powder, 24 to 36 parts by weight of a dispersion solvent, 2 to 4 parts by weight of a binder, 2 to 4 parts by weight of a plasticizer and 2 to 4 parts by weight of a dispersant .

The dispersion solvent may be at least one selected from the group consisting of methanol, ethanol, isopropyl alcohol, toluene, methyl ethyl ketone (MEK), diethyl ether, and trichlorethylene trichloroethylene), and mixtures thereof.

The dispersing agent may be selected from the group consisting of fish oil, polyethylene glycol (PEG), alcohol polyoxyethylene ether (AE), monoglyceride, sorbitan ester, nonionic surface active agent and combinations thereof Based dispersant selected from the group consisting of

The binder may be selected from the group consisting of cellulose, polyvinyl butyral (PVB), polymethyl methacrylate (PMMA), polyacryl esters, and combinations thereof. And may include any one of them.

Examples of the plasticizer include butyl benzyl phthalate (BBP), dibutyl phthalate (DBP), di-octyl phthalate (DOP), di-octyl-adipate (DOA) And a combination of these.

The ceramic powder may have an average particle diameter of 100 nm or less.

According to another embodiment of the present invention, there is provided a green sheet comprising 100 parts by weight of a ceramic powder, 2 to 4 parts by weight of a binder, 2 to 4 parts by weight of a plasticizer and 2 to 4 parts by weight of a dispersant, . ≪ / RTI >

The green sheet may be free from cracks in the ceramic sheet even when bent to 150 degrees or more.

An automotive exhaust gas sensor according to another embodiment of the present invention includes a ceramic sheet.

Hereinafter, the present invention will be described in more detail.

The term including an ordinal number such as the first or second in the present invention can be used to describe various elements, but the constituent elements are not limited by the terms, For example.

The method of manufacturing a green sheet of the present invention includes a first mixing step, a second mixing step, a third mixing step, and a film forming step, wherein the steps are sequentially performed.

The first mixing step includes a step of mixing a dispersion solvent and a dispersant to prepare a dispersion solution, and the second mixing step includes mixing a binder and a plasticizer with the dispersion solution to prepare a one-component solution And the third mixing step includes mixing ceramic powder and the one-component solution to prepare a ceramic slurry. The green sheet manufacturing method includes the first to third mixing steps in the above-described order, and the mixing procedure is one of the characteristics of the present invention that determines the characteristics of the green sheet.

The film forming step is a process of manufacturing a green sheet including a ceramic sheet by applying and drying a ceramic slurry prepared by the above process on a substrate.

The dispersion solvent may be at least one selected from the group consisting of methanol, ethanol, isopropyl alcohol, toluene, methyl ethyl ketone (MEK), diethyl ether, and trichlorethylene trichloroethylene), and at least one of the at least two solvents may be an alcohol-based solvent.

The dispersion solvent may be one having excellent solubility in the binder, and a mixed solvent containing the two or more solvents may be applied in order to obtain an excellent binder solubility.

The dispersion solvent may be a mixture of a first dispersion solvent and a second dispersion solvent which are two different dispersion solvents, at least one of the first dispersion solvent and the second dispersion solvent is an alcohol, and the first dispersion The solvent and the second dispersion solvent at a weight ratio of 1: 0.6 to 1.5. When the first dispersion solvent and the second dispersion solvent are contained in the above weight ratio, the solubility of the binder and the dispersibility of the ceramic powder are excellent, so that a uniform ceramic slurry can be produced and the properties of the green sheet can be improved .

Preferably, the dispersing solvent may comprise toluene and an alcohol. When the dispersion solvent contains both the toluene and the alcohol, the solubility of the binder can be improved and a green sheet having excellent properties can be produced.

The dispersing agent may be selected from the group consisting of fish oil, polyethylene glycol (PEG), alcohol polyoxyethylene ether (AE), monoglyceride, sorbitan ester, nonionic surface active agent and combinations thereof Based dispersant selected from the group consisting of The dispersant can improve the mixing degree and dispersibility of the binder and the ceramic powder together with the mixed solvent.

The binder may be selected from the group consisting of cellulose, polyvinyl butyral (PVB), polymethyl methacrylate (PMMA), polyacryl esters, and combinations thereof. And may include any one of them. The binder is indispensable in the process of forming the ceramic sheets by the ceramic powder, but if the binder is not sufficiently dispersed in the ceramic slurry, a microscopic unevenly mixed lump may be formed inside the slurry film, It is possible to form a cavity on the surface or inside of the finally obtained green seq and to form a protrusion made of powder, so that the surface shape and density of the green sheet can be lowered. However, in the present invention, the dispersing solvent can be appropriately utilized and the order of blending of the components in the manufacturing process can be optimized to improve the degree of dispersion of the binder and the ceramic particles in the ceramic slurry.

Examples of the plasticizer include butyl benzyl phthalate (BBP), dibutyl phthalate (DBP), di-octyl phthalate (DOP), di-octyl-adipate (DOA) And a combination of these. Use of the plasticizer can increase the flexibility of the green sheet.

The ceramic powder may include any one selected from the group consisting of zirconia, alumina, and combinations thereof. However, the ceramic powder is not limited thereto and can be applied to powders known as ceramics.

The ceramic powder may have an average particle diameter of 100 nm or less, and may be 0.1 to 100 nm. When the ceramic powder having the average particle diameter is used, it may be advantageous to produce a ceramic powder having a smaller thickness, and the average particle size of the ceramic powder may be suitably selected in consideration of the thickness, Can be selected and applied.

The ceramic slurry may be a mixture of the binder and the ceramic powder uniformly. In particular, the slurry may be a slurry having excellent dispersibility in which all the constituents including the binder, ceramic powder and the like do not form a lump.

The ceramic slurry may include 100 parts by weight of ceramic powder, 24 to 36 parts by weight of a dispersion solvent, 2 to 4 parts by weight of a binder, 2 to 4 parts by weight of a plasticizer and 2 to 4 parts by weight of a dispersant. In the case of producing the ceramic slurry within the above range of the content, the degree of dispersion of the ceramic slurry can be optimized and the produced green sheet can have high strength and high tensile properties regardless of the thin thickness.

The mixing of the first mixing step may be one hour or more and may be performed for one to two hours. When the mixing of the first mixing step is performed for 1 hour or more, the dispersion solvent and the dispersing agent are sufficiently mixed to improve the dispersibility of the binder and the ceramic powder to be mixed subsequently. The mixing of the first mixing step may preferably be performed for 1 to 2 hours. In this case, compared with the conventional mixing step for mixing the ceramic powder-dispersed solvent-dispersing agent for 6 hours or more in the first step, It is possible to produce a dispersion solution having a good dispersion degree.

The mixing of the second mixing step may be performed for 2 hours or more, and preferably for 2 to 3 hours. In the case where the mixing of the second mixing step is performed for 2 hours or more, the dispersion solvent, the binder and the plasticizer may be uniformly dispersed without forming uneven lumps. The mixing of the second mixing step may preferably be performed for 2 to 3 hours. Compared with the conventional method in which a step of adding a binder-plasticizer to a first-stage mixed material and mixing for 12 hours or more is required, the mixing according to the present invention is advantageous in that the time and cost required for mixing are greatly reduced, One-component solutions can be prepared.

In the third mixing step, mixing may be performed for 20 hours or more, preferably 20 to 28 hours, or may be performed by ball milling.

When the ceramic powder and the one-component solution are mixed for 20 hours or more, the ceramic powder and the binder are uniformly dispersed in the ceramic slurry, and a green sheet having excellent surface characteristics can be produced. Preferably, the mixing of the third mixing step may be performed for 20 to 28 hours. In this case, a ceramic slurry having excellent dispersion degree and solubility can be produced while greatly reducing the time and cost required for mixing.

The mixing of the third mixing step may be performed by a ball milling method. The ball milling may be performed by placing balls of solid metal or ceramics into the solution containing the ceramic powder and the one-component solution, and rotating the balls in the vessel so that the ceramic slurry is dispersed such that microscopic unevenly dispersed agglomerates are not formed . If the mixing of the third mixing step is performed by a ball milling method, the degree of mixing and degree of dispersion of the ceramic slurry can be improved.

The ceramic slurry thus prepared may be coated or applied on a substrate such as a base film by a conventional method to form a ceramic slurry in the form of a film and dried to prepare a green sheet containing a ceramic sheet, In addition, the green sheet may be subjected to a heat treatment or a sintering process.

As a method of coating and application, a tape casting method using a doctor blade can be preferably applied.

The method for producing the green sheet is a method for producing a green sheet having excellent characteristics by mixing each component in an appropriate order while using a dispersion solution containing an alcohol and optimizing the content of each component to obtain high density and high toughness A green sheet containing a ceramic sheet can be produced. In addition, the above methods are relatively simple processes such as mixing, and the manufacturing time can be shortened compared with the conventional manufacturing method, and a green sheet having thinner and better surface characteristics can be provided.

A ceramic slurry for the production of a green sheet according to another embodiment of the present invention comprises 100 parts by weight of a ceramic powder, 24 to 36 parts by weight of a dispersion solvent, 2 to 4 parts by weight of a binder, 2 to 4 parts by weight of a plasticizer, . The ceramic slurry can optimize the content of the binder, the dispersion solvent, and the ceramic powder to produce a ceramic slurry excellent in dispersibility and degree of blending.

The types and characteristics of the ceramic powder, dispersion solvent, binder, plasticizer, dispersant, and the like included in the ceramic slurry are the same as those described in the method of manufacturing a green sheet according to one embodiment of the present invention, .

The ceramic slurry is subjected to a molding and drying process to provide a thin, high-strength, high-strength green sheet having better surface characteristics.

The green sheet according to another embodiment of the present invention includes a ceramic sheet having a thickness of 250 탆 or less, and the thickness may be 20 to 250 탆.

The green sheet comprises 100 parts by weight of a ceramic powder, 24 to 36 parts by weight of a dispersion solvent, 2 to 4 parts by weight of a binder, 2 to 4 parts by weight of a plasticizer and 2 to 4 parts by weight of a dispersant.

The description of the types and characteristics of the ceramic powder, dispersion solvent, binder, plasticizer, dispersant, etc. contained in the green sheet is the same as that described in the method of manufacturing a green sheet according to one embodiment of the present invention, .

The green sheet may be one that does not crack in the ceramic sheet even when bent to 150 degrees or more.

The green sheet may have a thin thickness, at the same time, an excellent surface property, and a high quality with high strength and high toughness.

A sensor according to another embodiment of the present invention includes the ceramic sheet. The sensor may be manufactured by a method of manufacturing a green sheet according to an embodiment of the present invention. The ceramic sheet may have a thin thickness and at the same time have excellent surface characteristics, and may have a high strength, Lt; / RTI > The ceramic sheet can have excellent properties such as no warpage or de-lamination even if several layers are laminated and laminated.

The sensor including the ceramic sheet may be used, for example, in the manufacture of a gas sensor for an automobile exhaust gas sensor, but is not limited thereto and may be applied to any device manufactured by laminating a ceramic sheet or a green sheet .

INDUSTRIAL APPLICABILITY The method for producing a green sheet and the green sheet of the present invention are excellent in bonding property between ceramic particles, plasticity and peelability from a base film, and excellent dispersibility of raw material powder, and excellent surface properties without ruggedness, It is possible to provide a green sheet containing a high-density ceramic sheet. The green sheet has both a high density and a high toughness, so that it is possible to remarkably improve the de-lamination phenomenon occurring in the laminating process for producing the device, and the warp phenomenon in the electrode-formed portion printed in the same sheet during the co- . In addition, the green sheet can produce a green sheet comprising a ceramic sheet having a low porosity and a stable microstructure and a uniform grain size after the heat treatment.

1 is a manufacturing process diagram schematically showing a manufacturing process of a slurry according to an embodiment of the present invention.
FIG. 2 is a photograph showing the dried green sheet prepared according to Example 1 of the present invention and the peeling process with the base film. FIG.
FIG. 3 is a photograph of the surface properties of the green sheet prepared according to Example 1 of the present invention and Comparative Examples 1 and 2 by an optical microscope. FIG.
Fig. 4 is a photograph of a green sheet according to Example 1 of the present invention observed by a scanning electron microscope (SEM) after drying and after firing. Fig.
5 is a photograph of a cross section of a structure obtained by laminating several layers of a green sheet manufactured according to Example 1 of the present invention and sintering the same with a scanning electron microscope (SEM).

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

1 is a manufacturing process diagram schematically showing a method of manufacturing a green sheet according to the present invention. Specifically, in order to improve the dispersibility, the solvent 1 and the solvent 2 are mixed with a dispersant and mixed well using a shaker for 1 hour. Also, add the binder and plasticizer before adding ceramic powder and mix well for 2 hours using a shaker to dissolve sufficiently in the solvent. Then ceramic powder and zirconia balls are added, and then mixed using a ball-mill for 24 hours. Hereinafter, a production method of a specific example is described.

Example  One

3 g of fish oil as a dispersant was added to 33 g of a mixed solvent of toluene and ethanol and stirred for 1 hour using a shaker to prepare a dispersion solution step).

3 g of polyvinylbutyral (PVB) as a binder and 3 g of butyl benzyl phthalate (BBP) as a plasticizer were added to the dispersion solution, and the mixture was stirred and mixed for 2 hours using a shaker to obtain a one-component solution (Second mixing step).

100 g of YSZ (Yttria stabilized zirconia, average particle diameter: 90 nm) powder as a ceramic powder was added to the one-component solution and ball-milled together with a zirconia ball for 24 hours to prepare a ceramic slurry (third mixing step).

The ceramic slurry was cast on a base film to a thickness of 0.3 mm using a doctor blade and dried at 25 degrees Celsius for 24 hours to obtain a green sheet (Green sheet K13) of Example 1 having a thickness of 0.125 mm Forming step). The properties of K13 are evaluated and summarized in Table 1 below.

Comparative Example  One

3 g of fish oil as a dispersing agent was added to 33 g of a mixed solvent of toluene and MEK (methyl ethyl ketone) and stirred for 1 hour to obtain a dispersion solution.

3 g of polyvinylbutyral (PVB) as a binder and 3 g of butyl benzyl phthalate (BBP) as a plasticizer were added to the dispersion solution and stirred for 2 hours to obtain a one-part solution.

100 g of YSZ powder having an average particle diameter of 90 nm was added to the one-component solution and ball-milled with a zirconia ball for 24 hours to prepare a ceramic slurry.

The slurry was cast on a base film to a thickness of 0.3 mm on a base film using a doctor blade and dried at 25 DEG C for 24 hours to obtain a green sheet (Green sheet K11) of Comparative Example 1 with a thickness of 0.125 mm. The characteristics of K11 are summarized in Table 1, and wrinkles and cracks occurred due to poor surface condition, and the peelability was evaluated to be poor.

Comparative Example  2

2 g of polyethyleneglycol (PEG400) as a dispersant was added to 55 g of a mixed solvent of ethanol and MEK (methyl ethyl ketone) and stirred for 30 minutes to obtain a dispersion 1.

100 g of YSZ powder having an average particle diameter of 90 nm was added to the dispersion solution and ball milled together with a zirconia ball to obtain a dispersion 2.

15 g of PVB (polyvinylbutyral) as a binder and 5 g of a plasticizer BBP (butyl benzyl phthalate) were added to the dispersion 2 and ball-milled for 12 hours to prepare a ceramic slurry.

The ceramic slurry was cast on a base film to a thickness of 0.3 mm using a doctor blade and dried at 25 degrees Celsius for 12 hours to obtain a green sheet (Green sheet K12) of Comparative Example 2 having a thickness of 0.125 mm. The properties of the green sheet K12 were analyzed and are summarized in Table 1 below. Wrinkles and cracks occurred due to poor surface condition, and the peelability was also poor.

Example  2

3 g of fish oil as a dispersant was added to 45 g of a mixed solvent of toluene and ethanol and stirred for 1 hour using a shaker to obtain a dispersion solution (first mixing step).

7.5 g of PVB (polyvinylbutyral) as a binder and 7.5 g of butyl benzyl phthalate (BBP) as a plasticizer were added to the dispersion solution and stirred for 2 hours using a shaker to prepare a one-component solution (second mixing step).

100 g of alumina powder (average particle diameter, 90 nm) was added to the one-component solution and ball-milled with zirconia balls for 24 hours to prepare a ceramic slurry (third mixing step).

The ceramic slurry was cast on a base film to a thickness of 0.3 mm using a doctor blade and dried at 25 degrees Celsius for 24 hours to obtain a green sheet (Green sheet K23) of Example 2 having a thickness of 0.125 mm Film forming step). The characteristics of the green sheet K23 were analyzed and summarized in Table 1 below.

Experimental Example  - Example  And Comparative example  Property evaluation

The properties of the green sheets of the examples and comparative examples were evaluated in the following manner.

As for the bondability, both ends of the sheet were held by both hands and vibration was evaluated by vibration up and down, and evaluation was made based on whether or not cracks occurred in the sheet after vibration.

Regarding plasticity, the sheet was bent so as to be about 150 degrees, and a change in the shape of the sheet surface was observed and evaluated. The sheet was evaluated as excellent when cracks did not occur and the sheet was returned to its original state.

With respect to the peelability, the ceramic sheet formed on the base film was peeled off by hand, and evaluation was made that excellent peeling from the base film was excellent.

With respect to the surface property, the surface of the green sheet was evaluated by using an optical microscope, and those having no irregularities, cracks, wrinkles or the like were evaluated as excellent.

Cohesiveness Plasticity Peelability Surface property Example 1 ○ ○ ○ ○ Comparative Example 1 ○ △ △ ○ Comparative Example 2 ○ × △ × Example 2 ○ ○ ○ ○ Good: Fair: Fair: Bad:

As shown in Table 1, it was confirmed that the green sheet produced according to the embodiment of the present invention has significantly improved bonding properties, plasticity, peelability and surface properties as compared with the green sheet according to the comparative example.

FIG. 2 is a photograph showing the dried green sheet prepared according to Example 1 of the present invention and the peeling process with the base film. FIG. Referring to FIG. 2, the green sheet of Example 1 was evaluated as having a length of 2000 mm and a width of 150 mm, whereby the ceramic sheet from the base film was satisfactorily peeled off and the peelability was excellent, and the surface was uneven, cracked, And the surface property was evaluated to be excellent.

FIG. 3 is a photograph of the surface properties of the green sheet prepared according to Example 1 of the present invention and Comparative Examples 1 and 2 by an optical microscope. FIG. Referring to FIG. 3, the green sheet produced according to Example 1 had no irregularities or cracks on the surface, but it was confirmed that the green sheets of Comparative Examples 1 and 2 had irregularities or cracks on the surface thereof there was.

Fig. 4 is a photograph of a green sheet according to Example 1 of the present invention observed by a scanning electron microscope (SEM) after drying and after firing. Fig. The green sheet produced according to Example 1 had a shape in which the binder uniformly wrapped the ceramic powder, and after firing, the particles were uniformly and stably formed, and it was confirmed that a green sheet of high density / high toughness was produced.

5 is a photograph of a cross section of a structure obtained by laminating several layers of a green sheet manufactured according to Example 1 of the present invention and sintering the same with a scanning electron microscope (SEM). Referring to FIG. 5, cracks and de-lamination phenomena did not occur at the middle portion and the corner portion of the fired structure, and no warping due to shrinkage was observed.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, Of the right.

Claims (16)

A first mixing step of mixing a dispersion solvent and a dispersant to prepare a dispersion solution,
A second mixing step of mixing the binder and the plasticizer with the dispersion solution to prepare a one-component solution,
A third mixing step of mixing the ceramic powder and the one-component solution to prepare a ceramic slurry, and
A film forming step of applying a ceramic slurry on a substrate and drying the ceramic slurry to produce a green sheet including a ceramic sheet,
Lt; / RTI >
Wherein the dispersion solvent is a mixed solvent comprising at least two solvents selected from the group consisting of toluene, methanol, ethanol and isopropyl alcohol. The method according to claim 1,
Wherein the dispersion solvent is a mixed solvent comprising toluene and ethanol. The method according to claim 1,
The dispersing agent may be selected from the group consisting of fish oil, polyethylene glycol (PEG), alcohol polyoxyethylene ether (AE), monoglyceride, sorbitan ester, nonionic surface active agent and combinations thereof Wherein the non-ionic dispersant is a non-ionic dispersant. The method according to claim 1,
The binder may be selected from the group consisting of cellulose, polyvinyl butyral (PVB), polymethyl methacrylate (PMMA), polyacryl esters, and combinations thereof. Wherein the green sheet comprises one of the green sheet and the green sheet. The method according to claim 1,
Examples of the plasticizer include butyl benzyl phthalate (BBP), dibutyl phthalate (DBP), di-octyl phthalate (DOP), di-octyl-adipate (DOA) And a combination thereof. ≪ / RTI > The method according to claim 1,
Wherein the ceramic powder has an average particle diameter of 100 nm or less. The method according to claim 1,
In the ceramic slurry,
Wherein the ceramic powder comprises 24 to 36 parts by weight of a dispersion solvent, 2 to 4 parts by weight of a binder, 2 to 4 parts by weight of a plasticizer and 2 to 4 parts by weight of a dispersant based on 100 parts by weight of ceramic powder. delete delete The method according to claim 1,
Wherein the mixing in the first mixing step is performed for 1 to 2 hours. The method according to claim 1,
And mixing in the second mixing step is performed for 2 to 3 hours. The method according to claim 1,
And mixing in the third mixing step is performed by ball milling for 20 to 28 hours. delete The method of manufacturing a green sheet according to claim 1, wherein the ceramic sheet has a thickness of 250 탆 or less. The method of manufacturing a green sheet according to claim 1, wherein the green sheet does not crack in the ceramic sheet even when bent to 150 degrees or more. A sensor comprising a ceramic sheet included in a green sheet produced by the method according to claim 14 or 15.

Images