KR101265945B1 - Composite of body for lightweight ceramic ware and manufacturing method of the body for lightweight ceramic ware - Google Patents

Abstract

The present invention, SiO ₂ 40~75% by weight, Al ₂ O ₃ 10~35% by weight, K ₂ O and Na ₂ O 1~15 wt% and a solid content containing, CaO and MgO 0.1~15% by weight Lightweight ceramic composition containing 0.01 to 3% by weight of hydrophilic hollow polyacrylonitrile having a hydrophilic property by surface coating with ethanol or methanol in a slurry having water content of 25 to 45% by weight It relates to a method of manufacturing pottery. According to the present invention, since the hollow polyacrylonitrile surface-coated to have hydrophilicity is used, it can be mixed well with the water-containing ceramic slurry and can be uniformly mixed with the slurry without floating on top of the slurry. Therefore, there is no difficulty in controlling the crystal phase because it does not remain in the matrix, and the pores may be formed in the molding step, thereby making it possible to implement a lighter weight of ceramics.

Description

Composition for lightweight ceramics and manufacturing method of lightweight ceramics using the same {Composite of body for lightweight ceramic ware and manufacturing method of the body for lightweight ceramic ware}

The present invention relates to a composition for ceramics and a method of manufacturing ceramics using the same, and more particularly, because it uses hollow polyacrylonitrile surface-coated to have hydrophilicity, it is well mixed with a slurry for ceramics containing water on top of the slurry. It is not suspended and can be mixed with the slurry uniformly, and because it is burned during firing, it does not remain in the matrix, so there is no difficulty in controlling the crystal phase. It relates to a method of manufacturing lightweight ceramics using the same.

Ceramics can be defined as a family of tiles, kitchenware, sanitary ware, etc., after firing, as a ceramic product with or without milk. It is also called 'triaxial tableware' because the raw material used for making ceramics is composed of three components: clay, feldspar, and quartz.

In ceramics, clay provides plasticity to the body during the molding process and allows it to maintain sufficient molding strength to withstand the process of moving or decorating the molded body. In addition, after firing, the mullite phase and the glass phase are formed in the substrate, thereby contributing to maintaining sufficient strength in the use environment.

The chemical composition of feldspar is (K, Na, Ca, Ba) (Al, Si) 4O8. Feldspar is the main constituent of granite, and the feldspar produced naturally belongs to three monolithic groups: potassium feldspar (KAlSi3O8), soda feldspar (NaAlSi3O8), and calcium feldspar (CaAl2Si2O8). Potassium feldspar and calcium feldspar hardly form a solid solution, but potassium feldspar and soda feldspar, and soda and calcium feldspar form a continuous solid solution. Feldspar is used as a raw material for porcelain and acts as a flux to melt and densify clay or silica.

Silica is mainly composed of silica, and its fire resistance is SK32-35, which acts as a skeleton of the base during the forming and firing process and forms glass. Fine silica is pure white and easy to grind. Quartzite improves the whiteness and light transmittance of the base and improves the mechanical strength.

Raw materials such as kaolin, feldspar, and silica are used in such ceramic products, and show high specific gravity (2.6 or more). In this regard, a lot of research is being done by metropolitan asset companies to obtain energy savings (reduction of transportation costs, insulation, etc.) by lightening products. In order to reduce the weight of the product, development of light weight composition using low specific gravity (less than 2.5) raw material, porous body through pore forming agent, and research on reinforced thin plate material are being conducted.

When using low specific gravity materials such as talc, there are many difficulties in product development due to deterioration of moldability (fluidity, plasticity) and plasticity. During the research on weight reduction, there is an attempt to achieve lightweight by thinning the thickness of the product by using reinforcement. However, reinforcing substrates generally have to be calcined at high temperature (1300 ° C. or more) by adding an alumina composition, and there is a difficulty in that plasticity required for sheet forming is not high.

In light weight research of porcelain products, research on weight reduction through the formation of porous bodies is being conducted. The pore forming method for producing a porous body is roughly classified into a method of forming pores in a molding step and a method of forming pores during firing. As a material for forming pores in the molding step, pores are formed in the molded body by mixing a predetermined ratio with the raw material of ceramics using an organic component or an inorganic component. The method of forming pores during firing utilizes materials that form pores by burning during firing to generate gas or by generating gas during self-decomposition. In the method of forming pores during firing, it is difficult to control the uniform distribution and size of the pores, and there is a problem in that ignition and destruction of the magnetic body due to gasification during firing occur.

Therefore, many researches are being made to reduce the weight by manufacturing the porous body by distributing the pores forming materials in the forming step. Such pore-forming agents are roughly classified into organic and inorganic materials.

Inorganic matters do not burn during firing and remain in a matrix, which affects densification behavior and crystal phase control, which makes it difficult to secure physical properties of the fired products.

Organic materials generally have a hydrophobic property and do not mix well with a slurry for ceramics containing water, and are suspended in an upper portion of the slurry and thus cannot be uniformly mixed with the slurry.

The problem to be solved by the present invention is to use a hollow polyacrylonitrile surface-coated to have a hydrophilic property so that it can be mixed well with water-containing porcelain slurry, it can be uniformly mixed with the slurry without floating on top of the slurry, There is no difficulty in controlling the crystal phase because it does not remain in the matrix (combustion), and provides a composition for lightweight ceramics and a method for manufacturing lightweight ceramics using the same, by forming pores in the molding step to realize the weight reduction of ceramics.

The present invention, SiO ₂ 40~75% by weight, Al ₂ O ₃ 10~35% by weight, K ₂ O and Na ₂ O 1~15 wt% and a solid content containing, CaO and MgO 0.1~15% by weight The present invention provides a light ceramic composition comprising 0.01 to 3% by weight of hydrophilic hollow polyacrylonitrile having a hydrophilicity by surface coating with ethanol or methanol in a slurry having a water content of 25 to 45% by weight.

It is preferable that the viscosity of the said composition for light ceramics makes 3000-22000cp.

The hollow polyacrylonitrile has a hollow hollow sphere shape and preferably has an average particle diameter in the range of 10 to 150 µm.

The present invention also includes 40 to 75% by weight of SiO ₂ , 10 to 35% by weight of Al ₂ O ₃ , 1 to 15% by weight of K ₂ O and Na ₂ O, and 0.1 to 15% by weight of CaO and MgO. Preparing a slurry having a water content of 25 to 45% by weight by mixing solid content with water, and impregnating hollow polyacrylonitrile with ethanol or methanol to make the surface of the hollow polyacrylonitrile hydrophilic Surface coating, and hydrophilic surface-coated hollow polyacrylonitrile was added to the slurry to disperse to prepare a composition for lightweight ceramics, but mixed to contain 0.01 to 3% by weight of the hollow polyacrylonitrile. And a step of injecting and drying the light ceramic composition into a mold and drying the mold, and demolding the dried light ceramic composition and firing the molded body.

The viscosity of the composition for lightweight ceramics is preferably adjusted to the content of the moisture and the solid content and the content of the hollow polyacrylonitrile in a range of 3000 to 22000cp.

The hollow polyacrylonitrile is preferably made of hollow hollow spheres with an average particle diameter in the range of 10 to 150 μm.

The firing is preferably carried out for 10 minutes to 24 hours at a temperature of 1200 ~ 1280 ℃ in an air atmosphere.

In the manufacturing method of the light ceramics, it is preferable to add hydrophilic surface-coated hollow polyacrylonitrile to the slurry and to disperse the hollow polyacrylonitrile for 1 minute to 12 hours using an ultrasonic disperser.

According to the present invention, since the hollow polyacrylonitrile surface-coated to have hydrophilicity is used, it can be mixed well with the water-containing ceramic slurry and can be uniformly mixed with the slurry without floating on top of the slurry. Therefore, there is no difficulty in controlling the crystal phase because it does not remain in the matrix, and it is possible to realize the weight reduction of ceramics by forming pores in the forming step.

In addition, according to the present invention, the surface of the hollow polyacrylonitrile is coated with ethanol or methanol in order to improve the dispersibility, so that it can be well mixed with the slurry and the dispersibility is high.

In addition, the hollow polyacrylonitrile burns below 300 ° C. but retains defects in the form of pores with a large specific surface area and increases the specific surface area of the pore defects acts as a driving force to promote densification.

Figure 1 is a runner electron micrograph showing the fine shape of the polyacrylonitrile Hollow Microsphere (PAHM) having an average particle size of 30㎛.
Figure 2 is a runner electron micrograph showing the fine shape of the hollow polyacrylonitrile having an average particle size of 97㎛.
Figure 3 is an X-ray diffraction (XRD) pattern showing the crystal phase of the white porcelain slurry solids before firing.
Figure 4 is a graph showing the viscosity change of the composition for lightweight ceramics with the addition of PAHM.
5 is a graph showing the results of measuring the weight change during firing of the specimen without PAHM and the specimen without PAHM using the High Temperature Simultaneous Thermal Reaction Analyzer (TG-DTA).
Figure 6 is a graph showing the results of measuring the change in shrinkage rate (shrinkage rate) after firing at 1225 ℃ after drying the specimen molded by the injection molding method.
Figure 7 is a graph showing the results of measuring the change in shrinkage rate (shrinkage rate) after firing at 1240 ℃ after drying the specimen molded by the injection molding method.
8 is a graph showing the XRD pattern of the specimens fired at 1225 ℃.
9 is a graph showing the XRD pattern of the specimens fired at 1240 ℃.
10 is a graph showing the weight reduction rate of specimens fired at 1225 ° C.
11 is a graph showing the weight reduction rate of specimens fired at 1240 ° C.
12 is a graph showing the flexural strength of specimens fired at 1225 ° C.
FIG. 13 is a graph showing flexural strength of specimens fired at 1240 ° C. FIG.
14 is a graph showing the absorption of specimens fired at 1225 ° C.
15 is a graph showing the absorption of specimens fired at 1240 ° C.
16A is a scanning electron micrograph when 0.2% by weight of PAHM30 is added, and FIG. 16B is a scanning electron micrograph when 0.4% by weight of PAHM30 is added, and FIG. 16C is a scanning electron microscope when 0.6% by weight of PAHM30 is added. 16D is a scanning electron micrograph when 0.2 wt% of PAHM100 is added, and FIG. 16E is a scanning electron micrograph when 0.4 wt% of PAHM100 is added, and FIG. 16F is 0.6 wt% of PAHM100 added. Scanning electron micrograph of the case.
17 is a scanning electron micrograph showing the pore size present in the fired specimen by adding 0.6% by weight of PAHM100.
18 is a graph showing the pore shrinkage change of the specimen shown in FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the following embodiments are provided to those skilled in the art to fully understand the present invention, and may be modified in various forms, and the scope of the present invention is limited to the embodiments described below. It doesn't happen.

Lightweight ceramic composition according to a preferred embodiment of the present invention is a ceramic raw material containing at least clay, feldspar and silica, 40 to 75% by weight of SiO ₂ , 10 to 35% by weight of Al ₂ O ₃ , K ₂ O And 1 to 15% by weight of Na ₂ O and 0.1 to 15% by weight of CaO and MgO. In addition to the above components such as SiO ₂ , Al ₂ O ₃ in the raw material, components such as Fe ₂ O ₃ , Ti ₂ O, P ₂ O ₅ , BaO, B ₂ O ₃ may be further included within 5% by weight. The raw material is a raw material used in tableware, sanitary ware, tiles, clay bricks, bone china, etc., hereinafter referred to as light ceramics means a meaning including tableware, sanitary ware, tiles, clay bricks, bone china, etc. use.

Lightweight ceramic composition according to a preferred embodiment of the present invention, 40 to 75% by weight of SiO ₂ , 10 to 35% by weight of Al ₂ O ₃ , 1 to 15% by weight of K ₂ O and Na ₂ O, CaO and 0.01 to 3% by weight of a hollow polyacrylonitrile having hydrophilicity by surface coating with ethanol or methanol in a slurry having a content of 25 to 45% by weight of solids containing 0.1 to 15% by weight of MgO. It is contained.

The viscosity of the light ceramic composition is preferably in the range of 3000 to 22000 cp, and if the viscosity is less than 3000 cp, the moisture content may be too high, resulting in poor workability due to injection molding, and when the viscosity exceeds 22000 cp, fluidity This lack can cause difficulty in injection molding.

The hollow polyacrylonitrile has a hollow hollow sphere shape and preferably has an average particle diameter in the range of 10 to 150 µm.

According to a preferred embodiment of the present invention, there is provided a method for producing lightweight ceramics, comprising 40 to 75 wt% of SiO ₂ , 10 to 35 wt% of Al ₂ O ₃ , 1 to 15 wt% of K ₂ O and Na ₂ O, and CaO. And preparing a slurry having a water content of 25 to 45% by weight by mixing solids and water containing 0.1 to 15% by weight of MgO, and impregnating hollow polyacrylonitrile in ethanol or methanol. Surface coating of the surface of the polyacrylonitrile to have a hydrophilic property, and a hydrophilic surface-coated hollow polyacrylonitrile is added to the slurry and dispersed to prepare a composition for lightweight ceramics, wherein the hollow polyacrylonitrile Mixing 0.01 to 3% by weight, injecting and drying the lightweight ceramic composition into a mold, and demolding the dried lightweight ceramic composition and firing the demolded molded body. All.

In general, polyacrylonitrile (PAHM) is difficult to expect dispersibility in the slurry due to the lack of hydrophilicity. Therefore, in the present invention, in order to improve the dispersibility of the hollow polyacrylonitrile, the hollow polyacrylonitrile is surface-coated with ethanol or methanol and then mixed with the slurry.

The viscosity of the composition for light ceramics is preferably adjusted to the content of the water content and the solid content of the slurry and the hollow polyacrylonitrile in a range of 3000 to 22000cp. When the viscosity of the light ceramic composition is less than 3000cp, the water content is too high, the workability due to injection molding may be reduced, and when the viscosity exceeds 22000cp, there may be difficulty in injection molding due to the lack of fluidity.

The hollow polyacrylonitrile is preferably made of a hollow type sphere and has an average particle diameter in the range of 10 to 150 µm.

The firing is preferably carried out for 10 minutes to 24 hours at a temperature of 1200 ~ 1280 ℃ in an air atmosphere.

In the manufacturing method of the light ceramics, it is preferable to add hydrophilic surface-coated hollow polyacrylonitrile to the slurry and to disperse the hollow polyacrylonitrile for 1 minute to 12 hours using an ultrasonic disperser.

Since the composition for lightweight ceramics of the present invention contains hollow polyacrylonitrile, it is combusted at low temperature when firing to manufacture lightweight ceramics, so that only pores remain in the molded body, thereby making it possible to manufacture a porous ceramics.

Hereinafter, a porous body is prepared by injection molding by mixing with a white porcelain raw material using a hollow microsphere of a polyacrylonitrile component, and the hollow polyacrylonitrile is calcined from white porcelain raw material. The effects on the behavior, porous body formation, and weight reduction characteristics were investigated.

The starting material was a hollow microsphere of poly-acrylonitrile with an average particle size of 30 μm and 100 μm of poly-acrylonitrile in a slurry (33.4 wt% water content) of white porcelain material (1S, Korea Clay). acrylonitrile Hollow Microsphere (PAHM) was used in combination. Table 1 below shows the chemical composition of the white porcelain slurry.

SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ CaO MgO K ₂ O Na ₂ O TiO ₂ P ₂ O ₅ Ig.loss 71.6 19.2 0.49 0.13 0.08 1.96 0.97 0.04 0.05 5.55

The particle size of the white porcelain slurry was measured by laser diffraction (beckman coulter LS13320, U.S.A), and the average particle size was measured to be 6.8 mu m. Poly-acrylonitrile Hollow Microsphere (hereinafter referred to as "PAHM") of polyacrylonitrile (poly-acrylonitrile) was used as the average particle size of 30㎛ (PAHM30) and 97㎛ (PAHM100). As a result of observing 500 or more PAHM particles with a scanning electron microscope (SEM) (JSM-6390, JEOL, Japan), PAHM having an average particle size of 30 μm as shown in FIG. 1 (hereinafter referred to as 'PAHM30') Silver particles of 20 μm or smaller and 40 μm or larger were also observed. On the other hand, as shown in FIG. . The specific gravity of PAHM30, a pore former, was 0.030 (g / cc) ± 0.005 and POHM100 was 0.025 (g / cc) ± 0.005.

The crystalline phase of the white solid slurry before firing was analyzed by X-ray diffraction (XRD, Right D / max 2500v / pc, Rigaku, Japan). Solids of the slurry showed quartz, kaolinite, muscovite and albite crystal phases.

To the white porcelain slurry having a water content of 33.4% by weight, the pore-forming agent PAHM was added in the range of 0.0 to 0.8% by weight. The slurry to which the pore-forming agent was added was dispersed for about 10 minutes using an ultrasonic disperser to obtain a light ceramic composition. Injection molding method was utilized for the production of the molded body. Gypsum mold was sufficiently dried to use. The lightweight ceramic composition was injected into a mold, dried for 20 minutes, and demolded to form a molded body.

For the evaluation of the viscosity of the composition, it was measured with a Brookfield LV viscometer with a light ceramic composition. It was measured after holding for 60 seconds while maintaining the temperature of the composition for lightweight ceramics at a temperature of 0.1 rpm with a spindle s61 at 27 ° C.

The molded body was dried at room temperature for 24 hours, then heated up to 1225 ° C and 1240 ° C at 3 ° C / min, held at 1225 ° C and 1240 ° C for 30 minutes, and then cooled.

The shrinkage rate of the fired body was indicated by a shrinkage confirmation line of 10 cm in the long axis direction of the specimen, and the shrinkage rate was measured by measuring the shrinkage confirmation line displayed after firing.

For the weight reduction ratio, the weight ratio of the specimen without PAHM to the specimen was used.

The calcined body was processed to 40 * 4 * 3mm, and then surface polished, and three-point flexural strength was measured at a cross head speed of 0.5mm / min.

Scanning electron microscope (JSM-6390, JEOL, Japan) was used to observe the microstructure and pores before and after firing.

When preparing a porous body using PAHM, it is important to prepare a molded body in which PAHM is uniformly distributed in a slurry. In addition, the viscosity and fluidity of the light ceramic composition (white porcelain slurry, water, PAHM) are also important in the injection molding process. However, PAHM generally lacks hydrophilicity, so it is difficult to expect dispersibility in the slurry. Therefore, in the present invention, in order to increase the dispersibility of PAHM in the white porcelain slurry, PAHM was coated with ethanol and then mixed with the slurry. The surface-modified PAHM was added to 0.0-0.8% by weight relative to the slurry to prepare a light ceramic composition in which PAHM was well dispersed.

The viscosity change of the composition for lightweight ceramics according to the addition of PAHM is shown in FIG. The viscosity of the base slurry without PAHM was 6000 cps. As the amount of PAHM added increased, the viscosity increased due to the increase of solid content (white porcelain raw material and PAHM) in the composition for lightweight ceramics and the buoyancy of the hollow PAHM. Addition of 0.6% by weight of PAHM30 resulted in more than 20,000 cps. The PAHM30 is higher than PAHM100 at the same mass of PAHM added because the PAHM30 has a small particle size and a large number of particles are added. In addition, when the viscosity of the composition for lightweight ceramics is more than 23,000cp, the fluidity of the composition is insufficient, the molding was difficult due to the decrease in moldability and aggregation of PAHM.

In order to determine the weight change (combustion temperature) during firing of the specimen to which PAHM was added, a TG-DTA (High Temperature Simultaneous Thermal Reaction Analyzer, DTG-60H, Japan) was measured. As shown in FIG. 5, the sample to which 0.6 wt% of PAHM30 was added (see (b) of FIG. 5) showed a weight loss of about 3.5% more than that of the no addition sample (see (a) of FIG. 5). The weight loss of about 3.5% was shown by the combustion of PAHM in the vicinity of 180 ~ 350 ° C, and the firing behavior of white porcelain raw material was the same as that of no additive sample.

The specimens formed by injection molding were fired at 1225 ° C. and 1240 ° C. after drying, and their shrinkage rates are shown in FIGS. 6 and 7. Figure 6 is a graph showing the shrinkage of the specimens fired at 1225 ℃, Figure 7 is a graph showing the shrinkage of the specimens fired at 1240 ℃. In specimens at 1225 ° C. (see FIG. 6), shrinkage increased by about 3% as the amount of PAHM added increased. Specimens fired at 1240 ° C. (see FIG. 7) showed a shrinkage of 13.3% when 0.6 wt% was added, increasing by about 4% as the amount added increased. The increase in shrinkage rate with the addition of PAHM is believed to have acted as a driving force for the micropores to promote the densification behavior of white porcelain. In the case of PAHM, it burns below 300 ° C, but it is believed that the pore-type defects remain and the increase in the specific surface area of the pore defects acts as a driving force to promote densification. Since the pore size of PAHM30 is smaller than that of PAHM100, it is believed that the specific surface area is increased to further increase the shrinkage rate. In addition, the high shrinkage rate at 1240 ° C is thought to be the result of the densification behavior of white porcelain accelerated at high temperature.

Crystal phase analysis after firing for the specimens to which PAHM was added is shown in FIGS. 8 and 9. FIG. 8 is a graph showing XRD patterns of specimens fired at 1225 ° C., and FIG. 9 is a graph showing XRD patterns of specimens fired at 1240 ° C. FIG. Marked as 'PAHM 0' in FIGS. 8 and 9 are XRD patterns for specimens without added PAHM. When calcined at 1225 ° C., quartz (SiO ₂ ), mullite (Al ₆ Si ₂ O ₁₃ ), and glassy crystal phases were observed. The specimens calcined at 1240 ° C. were analyzed as similar crystal phases. Since PAHM was burned below 300 ° C, it did not appear to affect the crystal phase of the specimen.

Porous materials have properties of high absorption, low strength and light weight. The light weight rate of the specimen by PAHM addition is shown in FIGS. 10 and 11. 10 is a graph showing the weight reduction rate of the specimens fired at 1225 ℃, Figure 11 is a graph showing the weight reduction rate of the specimens fired at 1240 ℃. As the amount added increased, the weight reduction ratio increased overall. In the specimen added with 0.6 wt% of PAHM100, the weight reduction was 39%, and the weight reduction rate was about 2 to 3% higher in the specimen fired at 1240 ° C than at 1225 ° C. As the specific gravity difference between PAHM30 and 100 is 16%, the weight reduction ratio should also be shown as such a tendency, but in the case of PAHM30, it is observed that the difference in the light weight ratio is reduced due to the large number of fine particles and particles having a thickness of 50 μm or more.

The bending strength values of the fired specimens are shown in FIGS. 12 and 13. 12 is a graph showing the flexural strength of the specimens fired at 1225 ℃, Figure 13 is a graph showing the flexural strength of the specimens fired at 1240 ℃. The firing of the PAHM-free specimen at 1225 ° C. showed a strength value of 105 MPa. At 1240 ° C., the strength value was 121 MPa. Overall, the strength value decreased significantly as the amount of PAHM added increased. It is believed that as the amount of addition increases, pore formation increases and the strength decreases. Overall, the PAHM30 specimens showed slightly higher strength than PAHM100, and the specimens fired at 1240 ° C were slightly higher than those fired at 1225 ° C. Overall, the tendency of strength change by increasing amount of PAHM was similar.

Absorption rate of these specimens (absorption rate) results are high because it is porous as shown in Figure 14 and 15. 14 is a graph showing the absorption of the specimens fired at 1225 ℃, Figure 15 is a graph showing the absorption of the specimens fired at 1240 ℃. In the case of PAHM100 fired at 1225 ℃, the water absorption increased significantly and increased to 8.3% at 0.6% by weight. As the overall amount increased, the absorption rate also increased. The absorption rate at 1240 ° C was lower than that at 1225 ° C. In addition, the PAHM30 specimens showed lower overall absorption than the PAHM100 specimens. When the specimen without PAHM was calcined at 1240 ° C., the absorption rate was 0.3% or less, so the firing temperature was sufficient for densification. PAHM addition also promotes densification, as can be seen from the shrinkage results. Nevertheless, the high absorption rate is due to the formation of many surface pores, and moreover, the formation of open pores rather than waste pores in the matrix.

The microstructure observation results of the specimen fired at 1240 ° C. by adding 0.2%, 0.4%, and 0.6% by weight of PAHM are shown in FIGS. 16A to 16F. 16A is a scanning electron micrograph when 0.2% by weight of PAHM30 is added, and FIG. 16B is a scanning electron micrograph when 0.4% by weight of PAHM30 is added, and FIG. 16C is a scanning electron microscope when 0.6% by weight of PAHM30 is added. 16D is a scanning electron micrograph when 0.2 wt% of PAHM100 is added, and FIG. 16E is a scanning electron micrograph when 0.4 wt% of PAHM100 is added, and FIG. 16F is 0.6 wt% of PAHM100 added. Scanning electron micrograph of the case. In the case of PAHM100, it was observed that pores were formed relatively uniformly, and various pore formations of 1 to 90 μm were observed in the tissue of PAHM30 added specimen. These micropores are considered to have the greatest impact on weight reduction and strength reduction.

When PAHM was added, it was found that the shrinkage rate results (see FIGS. 6 and 7) promoted densification than the non-added specimens. The average particle size of the pores (more than 1000) in the fired specimens was measured to determine how much the pores that promoted densification resulted in shrinkage. As shown in FIG. 17, the average particle size of the pores remaining in the fired specimen was 93 μm, which was about 5% contraction than the average particle size of PAHM100 as shown in FIG. 18. This played a role in the addition of PAHM to promote densification by increasing the specific surface area due to the formation of micropores. Therefore, when no-added specimens shrink 12%, it is considered that the shrinkage rate is increased due to shrinkage of the pores.

As mentioned above, although preferred embodiment of this invention was described in detail, this invention is not limited to the said embodiment, A various deformation | transformation by a person of ordinary skill in the art within the scope of the technical idea of this invention is carried out. This is possible.

Claims (8)

40 to 75% by weight of SiO ₂ , 10 to 35% by weight of Al ₂ O ₃ , 1 to 15% by weight of K ₂ O and Na ₂ O, and 0.1 to 15% by weight of CaO and MgO, together with a solid content and water The surface-coating with ethanol or methanol in a slurry having a water content of 25 to 45% by weight, the light weight porcelain composition comprising 0.01 to 3% by weight of hollow polyacrylonitrile having hydrophilicity.
The composition of claim 1, wherein the viscosity of the composition for lightweight ceramics is in the range of 3000 to 22000 cps.
The composition of claim 1, wherein the hollow polyacrylonitrile has a hollow hollow sphere shape and an average particle diameter is in the range of 10 to 150 µm.
40 to 75% by weight of SiO ₂ , 10 to 35% by weight of Al ₂ O ₃ , 1 to 15% by weight of K ₂ O and Na ₂ O, and 0.1 to 15% by weight of CaO and MgO. To prepare a slurry having a water content of 25 to 45% by weight;
Impregnating hollow polyacrylonitrile in ethanol or methanol to surface-coating the surface of the hollow polyacrylonitrile to be hydrophilic;
Adding a hydrophilic surface-coated hollow polyacrylonitrile to the slurry and dispersing it to prepare a light ceramic composition, wherein the hollow polyacrylonitrile is mixed to contain 0.01 to 3% by weight;
Injecting the lightweight ceramic composition into a mold and drying the mold; And
Demolding the dried lightweight ceramic composition, and firing the demolded molded body.
The method of claim 4, wherein the viscosity of the composition for light ceramics is controlled to the content of the moisture and the solid content and the content of the hollow polyacrylonitrile in the range of 3000 to 22000cp.
The method of claim 4, wherein the hollow polyacrylonitrile is hollow hollow and has a spherical shape with an average particle diameter of 10 to 150 μm.
5. The method of claim 4, wherein the firing is carried out in an air atmosphere at a temperature of 1200 to 1280 ° C for 10 minutes to 24 hours.
The light weight porcelain according to claim 4, wherein a hydrophilic surface-coated hollow polyacrylonitrile is added to the slurry and the hollow polyacrylonitrile is dispersed for 1 minute to 12 hours using an ultrasonic disperser. Manufacturing method.

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