KR19990016261A - Demoulding Method of Ceramic Molded Body Prepared by Gel Casting Method - Google Patents
Demoulding Method of Ceramic Molded Body Prepared by Gel Casting Method Download PDFInfo
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Abstract
본 발명은 젤캐스팅법에 의한 세라믹 성형체의 제조방법에 관한 것이며; 그 목적은 금형내에서 젤화된 성형체의 탈형방법을 제공함에 있다.The present invention relates to a method for producing a ceramic formed body by the gel casting method; The object is to provide a method for demolding a gelled molded body in a mold.
상기 목적을 달성하기 위한 본 발명은, 증류수에 아크릴아마이드와 메칠렌비스아크릴아마이드를 첨가한 용액에 세라믹분말을 혼합하고 슬러리를 만든 후, 탈포하고, 탈포된 슬러리를 탈형제가 도포된 금형에 부어서 젤화시킨 후 젤화된 성형체를 탈형하고, 이어 건조하는 공정을 포함한 젤캐스팅 방법에 있어서, 상기 탈형제로 사염화탄소(CCl4)을 사용하는 것을 포함하여 이루어지는 젤캐스팅법으로 제작한 세라믹 성형체의 탈형방법에 관한 것을 그 요지로 한다.The present invention for achieving the above object, after mixing the ceramic powder in a solution in which acrylamide and methylene bisacrylamide is added to distilled water and making a slurry, defoaming, and pouring the defoaming slurry into a mold coated with a mold release agent gelation In the gel casting method comprising the step of demolding the gelled molded body, and then drying, the method relates to the demoulding method of the ceramic molded body produced by the gel casting method comprising the use of carbon tetrachloride (CCl 4 ) as the release agent. That's the point.
Description
본 발명은 젤캐스팅법에 의한 세라믹 성형체의 제조방법에 관한 것으로써, 보다 상세하게는 금형내에서 젤화된 성형체의 탈형시 용이하게 탈형하고, 특히 성형체의 표면에 흠이 생기지 않게 탈형하는 방법에 관한 것이다.The present invention relates to a method for producing a ceramic molded body by the gel casting method, and more particularly, to a method for demolding easily during demolding of a gelled molded body in a mold, and particularly to a method of demolding without scratches on the surface of the molded body. will be.
파인세라믹스는 내열성, 내마모성, 내식성 등의 특성이 매우 우수하여 여러산업에 광범위하게 응용되고 있으며, 각 부품들은 단순형상에서 부터 복잡형상에 이르기 까지 다양한 형상을 갖고 있다. 특히, 복잡형상의 세라믹스를 제작하는 기술은 매우 어려운 공정으로 알려져 있다. 따라서, 저렴한 가격으로 재현성 있는 복잡형상의 세라믹스를 제작할 수 있는 기술의 개발은 필수적이다.Fine ceramics is widely used in various industries because of its excellent heat resistance, abrasion resistance, and corrosion resistance, and each part has various shapes ranging from simple to complex shapes. In particular, the technique of manufacturing a complicated ceramics is known as a very difficult process. Therefore, it is essential to develop a technology capable of producing reproducible complex ceramics at low cost.
현재까지 알려진 복잡형상 제작기술은 사출성형(injection molding), 슬립 캐스팅(slip casting), 가공(machining) 등의 기술이 알려져 있다. 사출성형은 성형체내에 결합제가 20-25중량% 이상 함유되어 있어서 결합제 제거시 성형체가 허물어지거나, 균열발생 등의 문제가 있어서 두꺼운(10mm 이상) 기물을 제작하기가 어렵다. 또한, 슬립 캐스팅은 성형체 내부에 밀도구배가 생성되어서 소결시 악영향을 미치며, 성형체의 강도가 낮아서 잘 파손되는 단점이 있다. 그리고, 가공에 의한 성형체 제작은 가격이 매우 비싸서 경제성이 없다.Complex shape manufacturing techniques known to date are known such as injection molding, slip casting, machining and the like. Injection molding is more than 20-25% by weight of the binder contained in the molded body, it is difficult to produce a thick (10mm or more) because there is a problem such as collapse of the molded body or cracking when removing the binder. In addition, slip casting has a disadvantage in that the density gradient is generated inside the molded body, which adversely affects the sintering, and is damaged well due to the low strength of the molded body. In addition, the production of molded articles by processing is very expensive and economical.
이러한 기존의 복잡형상 제작기술의 단점을 극복하기 위하여 개발된 것이 젤캐스팅(Gelcasting; US Pat. No. 4894194, Jan. 16, 1990) 법이다.Gelcasting (US Pat. No. 4894194, Jan. 16, 1990) has been developed to overcome the shortcomings of the existing complex shape manufacturing technology.
젤캐스팅법은 세라믹 공정과 중합체(Polymer) 제작기술을 혼합한 기술로서, 단량체(monomer)를 녹인 용액에 세라믹 분말을 혼합하여 슬러리를 만들고, 이어 젤화반응을 유발시키는 개시제 및 촉매를 첨가하여 단량체들을 중합체화 시킴으로써 세라믹 성형체를 제작하는 기술이다. 이 방법은 혼합 슬러리 자체가 유동성이 좋은 졸(sol) 상태에서 곧바로 젤(gel)화되는 것이므로 성형체가 균일하고, 첨가된 결합제의 량이 4중량% 미만이기 때문에 결합제 제거가 용이하고 두꺼운 기물을 제작할 수 있는 장점이 있다. 또한, 성형체의 강도가 매우 높아서 성형체 상태에서 파손없이 가공을 손쉽게 할 수도 있다.Gel casting method is a technology that combines the ceramic process and polymer manufacturing technology. The monomer is mixed with a ceramic powder in a solution of monomers to make a slurry, and then monomers are added by adding an initiator and a catalyst that causes a gelation reaction. It is the technique of manufacturing a ceramic molded object by making it polymerize. In this method, since the mixed slurry itself is directly gelled in a sol state with good fluidity, the molded body is uniform, and since the amount of the added binder is less than 4% by weight, it is easy to remove the binder and produce a thick substrate. There is an advantage. In addition, the strength of the molded body is so high that processing can be easily performed without damage in the molded body state.
그런데, 이 방법은 탈형제(release agent)를 사용하지 않으면 금형안에서 젤화된 성형체를 금형으로부터 손쉽게 탈형하기가 곤란하여 탈형과정에서 성형체가 파손될 수 가 있다.However, in this method, it is difficult to easily demold the gelled molded body from the mold without using a release agent, and the molded body may be damaged during the demolding process.
기존의 탈형방법으로, 슬러리를 금형내로 붇기 전에 금형표면에 탈형제(release agent)로 실리콘을 함유하지 않는 레진을 도포하는 방법이 소개된 바 있다(Journal of American Ceramic Society, Vol. 74, No. 3,612-618(1991)).As a conventional demolding method, a method of applying a resin containing no silicone as a release agent to a mold surface before pouring the slurry into a mold has been introduced (Journal of American Ceramic Society, Vol. 74, No. 3,612-618 (1991).
이러한 탈형제를 사용하는 경우, 사용하지 않는 것 보다는 탈형이 양호하지만, 여전히 접착력이 존재하여 효과적인 탈형이 되지않고 특히 탈형과정에서 성형체의 표면에 흠을 남기는 문제가 있다.In the case of using such a demolding agent, demolding is better than not used, but there is still a problem in that the adhesive force is present so that it is not an effective demolding, and in particular, the surface of the molded body is damaged during the demolding process.
이에, 본 발명은 상기 종래문제를 해결하기 위해 안출된 것으로써, 금형내에서 젤화된 성형체를 탈형할 때 탈형이 매우 용이하게 됨과 더불어 성형체의 표면에 흠이 생기지 않는 탈형방법을 제공하는데, 그 목적이 있다.Accordingly, the present invention has been made in order to solve the above-mentioned conventional problems, to provide a demolding method that is very easy to demold when demolding the gelled molded body in the mold and does not appear on the surface of the molded body, the object There is this.
상기 목적을 달성하기 위한 본 발명은, 증류수에 아크릴아마이드와 메칠렌비스아크릴아마이드를 첨가한 용액에 세라믹분말을 혼합하고 슬러리를 만든 다음, 탈포하고, 탈포된 슬러리를 탈형제가 도포된 금형에 부어서 젤화시킨 후 젤화된 성형체를 탈형하고, 이어 건조하는 공정을 포함한 젤캐스팅 방법에 있어서, 상기 탈형제로 사염화탄소(CCl4)을 사용하는 것을 포함하여 구성된다.In order to achieve the above object, the present invention is to prepare a slurry by mixing a ceramic powder in a solution in which acrylamide and methylene bisacrylamide are added to distilled water, and then defoaming, and pouring the defoaming slurry into a mold coated with a mold release agent and gelling the same. In the gel casting method comprising the step of demolding the gelled molded body and then drying, it comprises the use of carbon tetrachloride (CCl 4 ) as the demolding agent.
이하, 본 발명을 상세히 설명한다.Hereinafter, the present invention will be described in detail.
일반적으로 젤캐스팅방법은, 먼저 증류수에 단량체인 아크릴아마이드(acrylamide) 및 메칠렌비스아크릴아마이드(N,N'-methylenebisacrylamide)를 녹이고, 이 용액에 pH를 적정범위로 조절하기 위해 예를들면, 테트라메칠암모니움하이드록사이드(tetramethylammoniumhydroxide)를 첨가하여 pH=11-13으로 조정한다.In general, the gel casting method first dissolves acrylamide and methylene bisacrylamide (N, N'-methylenebisacrylamide) as monomers in distilled water and, for example, in order to adjust the pH to an appropriate range in the solution, Methylammonium hydroxide (tetramethylammoniumhydroxide) is added to adjust pH = 11-13.
상기 용액에 세라믹분말을 혼합하여 슬러리를 만들고 장시간 혼합한다. 이후 슬러리에 있는 기포를 제거하기 위해 탈포하는데, 이때 이온성이 없는 폴리에테르 또는 아미드계 용액을 첨가하면 그 효과가 크다. 그 탈포는 상온하 진공분위기에서 약 10-20분 동안 진행된다.Ceramic powder is mixed with the solution to make a slurry and mixed for a long time. After degassing to remove bubbles in the slurry, the effect is great if the non-ionic polyether or amide-based solution is added. The defoaming proceeds for about 10-20 minutes in a vacuum at room temperature.
상기와 같이 탈포된 슬러리를 금형에 부어 젤화시키기 전에 슬러리에 젤화 개시제와 촉매 예를들면, 암모니움퍼슬페이트(ammoniumpersulfate) 와 테트라메칠에칠렌다이아민(N,N,N'N'-tetramethylethylenediamine)을 혼합하면 젤화가 효과적으로 일어난다.The gelation initiator and catalyst, for example, ammoniumpersulfate and tetramethylethylenediamine (N, N, N'N'-tetramethylethylenediamine) are mixed in the slurry before the degassed slurry is poured into a mold and gelated. Gelation effectively occurs.
이상과 같이 만들어진 슬러리를 금형에 부어 젤화시킨 후 젤화된 성형체를 탈형하는데, 이때 성형체가 금형에서 쉽게 탈형됨과 더불어, 성형체의 표면에 흠이 생기지 않는 것이 무엇보다 중요하다.The slurry made as described above is poured into a mold and gelled, and then the gelled molded body is demolded. In this case, it is important that the molded body is easily demolded from the mold and that the surface of the molded body is not damaged.
본 발명에 의하면, 금형표면에 도포되는 탈형제는 젤화되기전 슬러리내에 존재하는 증류수의 젖음성(wetability), 그리고 젤화된 후 형성되는 중합체(polymer) 와의 반응성이 없어야 성형체의 표면에 흠이 생기지 않고 쉽게 탈형되는 것임을 알 수 있었다.According to the present invention, the mold release agent applied to the surface of the mold must be free from scratches on the surface of the molded body without the wettability of the distilled water present in the slurry before gelation and the reactivity with the polymer formed after gelation. It can be seen that the demoulding.
본 발명은 이러한 점을 고려하여, 증류수와의 반응성이 없고, 아크릴아마이드 및 메칠렌비스아크릴아마이드로 이루어진 중합체와의 반응성이 없는 사염화탄소(CCl4)를 탈형제로 사용하는데, 그 특징이 있다.In view of this point, the present invention uses carbon tetrachloride (CCl 4 ), which has no reactivity with distilled water and no reactivity with a polymer made of acrylamide and methylene bisacrylamide, is characterized by its release agent.
본 발명에 따라, 사염화탄소가 도포된 금형에 슬러리를 부어 젤화시킨 후, 젤화된 성형체를 탈형하면 성형체 표면에 흠이 전혀 발생하지 않는다. 이어, 성형체는 통상의 방법으로 건조, 소결하면 본 발명이 완성된다.According to the present invention, after the slurry is poured into a die coated with carbon tetrachloride and gelled, demolding the gelled molded body does not cause any scratch on the surface of the molded body. Subsequently, when a molded object is dried and sintered by a conventional method, this invention is completed.
위에서 언급한 바와같이, 본 발명의 탈형방법은 증류수와 단량체인 아크릴아마이드 및 메칠렌비스아크릴아마이드의 관계하에서 탈형의 우수성이 결정되므로, 기타 다른 조건 예를들면, 세라믹 분말, 개시제, 촉매의 영향을 받지 않으므로 이조건에 의해 한정되는 것이 아니다.As mentioned above, the demolding method of the present invention determines the excellence of demolding under the relationship between distilled water and the monomers acrylamide and methylene bisacrylamide, so that other conditions such as ceramic powder, initiator and catalyst It is not limited by this condition because it is not received.
이하, 본 발명을 실시예를 통하여 구체적으로 설명한다.Hereinafter, the present invention will be described in detail through examples.
[실시예]EXAMPLE
증류수에 단량체인 아크릴아미드를 14.6wt%, 메칠렌비스아크릴아마이드를 0.6wt%가 되게 첨가하고 녹인 후 테트라메칠암모니움하이드록사이드를 사용하여 용액의 pH를 12.7로 조정하여서 이 용액에 탄화규소 분말을 50vol%가 되게 첨가하고 24 시간 동안 혼합하였다. 이렇게 제조한 슬러리에 폴리에테르 또는 아미드계 용액을 0.5wt% 첨가하고 혼합한 후 기포가 보이지 않을 때까지 상온에서 진공탈포 시켰다. 이렇게 제조한 세라믹 슬러리에 젤화 개시제인 암모니움퍼슬페이트(ammonium-persulfate)와 촉매인 테트라메칠에칠렌다이아민(N,N,N',N'-teramethylethylenediamine)을 혼합하여 슬러리를 제조한 후 하기 표1과 같이 준비한 각각의 금형속에 부어 젤화시킨후 탈형한 다음, 성형체 표면을 관찰하고 그 결과를 하기표 1에 나타내었다.14.6 wt% of monomer acrylamide and 0.6 wt% of methylene bisacrylamide were added to the distilled water, and the solution was dissolved in tetramethylammonium hydroxide to adjust the pH of the solution to 12.7. Was added to 50 vol% and mixed for 24 hours. 0.5 wt% of a polyether or amide solution was added to the slurry thus prepared, and the mixture was vacuum degassed at room temperature until no bubbles were observed. The slurry was prepared by mixing ammonium persulfate (ammonium-persulfate), which is a gelling initiator, and tetramethylethylenediamine (N, N, N ', N'-teramethylethylenediamine), which were prepared in the ceramic slurry. Poured into each mold prepared as described above and then gelled and demolded, the surface of the molded body was observed and the results are shown in Table 1 below.
상기 표 1에 나타난 바와같이 탈형제가 도포되지 않은 비교예의 경우 탈형이 극히 불량할 뿐만 아니라 성형체가 파손되었으며, 레진계의 발명예를 사용한 종래예의 경우는 탈형은 되어도 부착력이 남아 있어 성형체 표면에 흠이 발생하였다. 이에 반해 본 발명의 경우 사염화탄소(CCl4)를 사용한 경우는 증류수 및 성형체내의 폴리머와의 반응성 및 젖음성이 없어 탈형이 매우 양호하였고, 탈형후 성형체 표면에 흠발생이 전혀 없었다.As shown in Table 1, in the comparative example without the demolding agent applied, not only the demolding was extremely poor, but also the molded body was broken. In the case of the conventional example using the resin-based invention, the adhesive force remains even when demolded, so that the surface of the molded body is scratched. Occurred. On the contrary, in the case of using the carbon tetrachloride (CCl 4 ) in the present invention, the demoulding property was very good because there was no reactivity and wettability with distilled water and the polymer in the molded body, and there was no flaw on the surface of the molded body after demolding.
본 발명의 실시예에서 세라믹분말로 탄화규소분말을 사용하였으나, 본 발명은 이에 한정되는 것이 아니다.Although the silicon carbide powder was used as the ceramic powder in the embodiment of the present invention, the present invention is not limited thereto.
상술한 바와같이, 본 발명에 의하면 젤화된 성형체가 금형에서 매우 용이하게 탈형되고, 특히 성형체의 표면에 흠이 생기지 않는 유용한 효과가 있다.As described above, the present invention has a useful effect that the gelled molded body is demolded very easily in the mold, and in particular, the surface of the molded body does not have any scratches.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1019970038746A KR19990016261A (en) | 1997-08-13 | 1997-08-13 | Demoulding Method of Ceramic Molded Body Prepared by Gel Casting Method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1019970038746A KR19990016261A (en) | 1997-08-13 | 1997-08-13 | Demoulding Method of Ceramic Molded Body Prepared by Gel Casting Method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| KR19990016261A true KR19990016261A (en) | 1999-03-05 |
Family
ID=66000603
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| KR1019970038746A KR19990016261A (en) | 1997-08-13 | 1997-08-13 | Demoulding Method of Ceramic Molded Body Prepared by Gel Casting Method |
Country Status (1)
| Country | Link |
|---|---|
| KR (1) | KR19990016261A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100680612B1 (en) * | 2005-07-01 | 2007-02-08 | 삼성전자주식회사 | Indoor unit of ventilation device |
| KR101329392B1 (en) * | 2011-12-21 | 2013-11-14 | 재단법인 포항산업과학연구원 | METHOD FOR MANUFACTURING FORMED SiC PRODUCT FOR GROWTH OF SiC SINGLE CRYSTAL |
| KR102048310B1 (en) * | 2019-04-26 | 2020-01-08 | 오창용 | Method and Device For Preparing Ceramic Plate Using Gel-Casting Process |
-
1997
- 1997-08-13 KR KR1019970038746A patent/KR19990016261A/en not_active Application Discontinuation
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100680612B1 (en) * | 2005-07-01 | 2007-02-08 | 삼성전자주식회사 | Indoor unit of ventilation device |
| KR101329392B1 (en) * | 2011-12-21 | 2013-11-14 | 재단법인 포항산업과학연구원 | METHOD FOR MANUFACTURING FORMED SiC PRODUCT FOR GROWTH OF SiC SINGLE CRYSTAL |
| KR102048310B1 (en) * | 2019-04-26 | 2020-01-08 | 오창용 | Method and Device For Preparing Ceramic Plate Using Gel-Casting Process |
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