JPH0157642B2 - - Google Patents
Info
- Publication number
- JPH0157642B2 JPH0157642B2 JP16812083A JP16812083A JPH0157642B2 JP H0157642 B2 JPH0157642 B2 JP H0157642B2 JP 16812083 A JP16812083 A JP 16812083A JP 16812083 A JP16812083 A JP 16812083A JP H0157642 B2 JPH0157642 B2 JP H0157642B2
- Authority
- JP
- Japan
- Prior art keywords
- mold
- glue
- cellulose
- added
- slip casting
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000003292 glue Substances 0.000 claims description 28
- 229920002678 cellulose Polymers 0.000 claims description 21
- 239000001913 cellulose Substances 0.000 claims description 21
- 238000007569 slipcasting Methods 0.000 claims description 17
- 229910052602 gypsum Inorganic materials 0.000 claims description 14
- 239000010440 gypsum Substances 0.000 claims description 14
- 238000010438 heat treatment Methods 0.000 description 13
- 239000011505 plaster Substances 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 239000000843 powder Substances 0.000 description 4
- 239000000919 ceramic Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000010304 firing Methods 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000008034 disappearance Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000012778 molding material Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000011265 semifinished product Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 238000010186 staining Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B1/00—Producing shaped prefabricated articles from the material
- B28B1/26—Producing shaped prefabricated articles from the material by slip-casting, i.e. by casting a suspension or dispersion of the material in a liquid-absorbent or porous mould, the liquid being allowed to soak into or pass through the walls of the mould; Moulds therefor ; specially for manufacturing articles starting from a ceramic slip; Moulds therefor
- B28B1/261—Moulds therefor
- B28B1/262—Mould materials; Manufacture of moulds or parts thereof
- B28B1/264—Plaster
Description
〔発明の利用分野〕
本発明は、たとえばセラミツク粉末、金属粉
末、炭素粉末などの耐火性粉末を含むスリツプ
（泥漿）を鋳込んで成形体を得るためのスリツ
プ・キヤステイング用鋳型に係り、特に逆勾配で
抜去できないような形状複雑な中子を必要とする
成形体の成形に好適なスリツプ・キヤステイング
用鋳型に関するものである。
〔発明の背景〕
空洞部の形状が複雑な中空成形体、すなわち逆
勾配で抜去できないような形状複雑な中子を必要
とする成形体をスリツプ・キヤステイングで成形
する場合、従来の石膏鋳型では中子の除去が困難
もしくは不可能であつた。
そこで、本願出願人は石膏鋳型にセルロース、
たとえば片状セルロース（植物繊維）を２−20％
の範囲で添加することおよび若干の加熱操作によ
り鋳型、特に中子の崩壊性を格段に向上させる鋳
型を開発し、本願に先立ち特開昭59−190811号公
報にて提案ずみである。しかし、その先願に係る
技術においては、セルロースの添加により鋳型の
初期強度の低下率がやや大きいこと、および加熱
操作後の鋳型の崩壊性が完全とはいい難いことな
どから、より一層の改善が望まれていた。
〔発明の目的〕
本発明は、上記の問題点を解決するためになさ
れたもので、鋳型の初期強度をあげるとともに、
加熱操作後の鋳型崩壊性を格段に向上し、いかな
る複雑な形状の中子であつても、その除去が容易
なスリツプ・キヤステイング用鋳型を提供するこ
とを、その目的としている。
〔発明の概要〕
本発明に係るスリツプ・キヤステイング用鋳型
の構成は、セルロースを添加した石膏鋳型からな
るスリツプ・キヤステイング用鋳型において、前
記石膏鋳型をニカワを含有するものとしたもので
ある。
なお付記すると、本発明のスリツプ・キヤステ
イング用鋳型は、例えばセラミツク粉末などを含
むスリツプを鋳込んで形形するために用いる、片
状セルロースを含んだ石膏鋳型において、石膏鋳
型に微量のニカワを添加するものである。
次に本発明がなされた考え方について述べる。
セルロースを含有する石膏鋳型に、さらにニカ
ワを微量添加する理由は、ニカワの添加により鋳
型の初期強度を上昇させると共に、加熱操作後の
鋳型の崩壊性を格段に向上させるためである。
含有するセルロースが、吸水性と共に水不溶性
の性質を備えるものであれば一層好ましい。
本発明において吸水性のセルロースとして好ま
しいものは、短かく裁断し片状にしたものであ
る。その理由は、片状にすると鋳型機料の流動性
が良くなるからである。また、セルロースを原料
とした紙類などでも良く、この場合、例えば薄葉
紙などは吸水性かつ水不溶性の点から好ましく、
片状にして石膏スラリーに均一に分散して使用す
る。
石膏鋳型にセルロースとニカワを含有させる理
由は、ニカワの添加により鋳型の初期強度を高め
ると共に、鋳込後のスリツプ成形品を中子と共に
加熱しセルロースとニカワを燃焼させて、鋳型の
粘結力を失なわせ鋳型の初期強度をゼロ近くに低
下させるためである。
また、石膏に混用する物質が水溶性であると石
膏粒子間にこのような物質が充填され、吸水性が
甚しく低下するがセルロースの場合は水不溶性で
ある為このような問題は生じない。
石膏鋳型に吸水性のセルロースを含有させる理
由は、スリツプからの鋳型の吸水効果を高めてス
リツプの固化時間を短縮するためである。
石膏100重量部に、セルロースを２〜30重量部
含有させた石膏鋳型に、ニカワを添加する量は
0.2〜1.0重量部であることが望ましい。
添加量は0.05重量部以下では、ニカワ添加の効
果が殆んど現われない、すなわち鋳型の初期強度
が４Kg/cm2以下と小さいままなので、スリツプ鋳
込時などに破損しやすく取扱いが困難であり、加
熱後の残留圧縮強度（以下「残留強度」と称す）
がやや大きく、鋳型の除去に困難が伴なうからで
ある。
また、ニカワの添加量が2.00重量部以上では、
ニカワ添加による石膏鋳型の硬化時間の遅延が甚
しく、到底実用に供しえない。
したがつて、ニカワの添加量は石膏100重量部
に対し、0.05〜2.00重量部が適当である。
本発明の鋳型を得るための、スリツプの鋳込み
から成形体の焼成までの工程は、スリツプの鋳込
み→加熱による鋳型（中子）中のセルロースとニ
カワの消失→鋳型の崩壊および除去→成形体の焼
成の順次で実施される。
造形後の鋳型は、80℃で約４時間加熱すること
により十分な乾燥状態となり、スリツプ中の水分
を吸収するのに適当な状態となる。ニカワが添加
されているので、無添加の場合に比べて十分な初
期強度を備えている。
セルロースおよびニカワを焼失させるための加
熱温度は、500℃程度で良く、セルロースおよび
ニカワの焼失により石膏鋳型は粘結力を失ない、
0.2Kg/cm2以下の外力によつて容易に崩壊する。
したがつて外力は、例えば極めて微弱な圧縮空
気もしくは真空吸引が好ましく、これらによれば
崩壊および条去を同時に行なうことができる。
石膏鋳型（中子）の除去によつて未焼成の成形
体（半完成品）が造られ、その後の焼成によつて
完全な、セラミツクもしくは金属等の成形体が得
られる。
〔発明の実施例〕
以下、具体的な実施例によつて説明する。
実施例 １
石膏に片状セルロース、ニカワおよび水を第１
表に示す割合で添加し、200rpmで５分間混練し
た。
[Field of Application of the Invention] The present invention relates to a slip casting mold for obtaining a molded body by casting a slip containing refractory powder such as ceramic powder, metal powder, carbon powder, etc. The present invention relates to a slip casting mold suitable for molding a molded article that requires a complex-shaped core that cannot be removed due to a reverse slope. [Background of the Invention] When molding a hollow molded body with a complicated cavity shape, that is, a molded body that requires a core with a complicated shape that cannot be removed due to a reverse gradient, by slip casting, it is difficult to use conventional plaster molds. Removal of the core was difficult or impossible. Therefore, the applicant of this application applied cellulose to the plaster mold.
For example, 2-20% flaky cellulose (plant fiber)
We have developed a mold that dramatically improves the disintegration properties of the mold, especially the core, by adding within this range and by a slight heating operation, and this was proposed in JP-A-59-190811 prior to the filing of this application. However, in the technology related to that earlier application, the rate of decrease in the initial strength of the mold was somewhat large due to the addition of cellulose, and the disintegration of the mold after heating was not perfect, so further improvements were needed. was desired. [Object of the invention] The present invention was made to solve the above problems, and it increases the initial strength of the mold, and
The object of the present invention is to provide a slip casting mold which has significantly improved mold disintegration properties after heating operations and which allows easy removal of cores of any complicated shape. [Summary of the Invention] The structure of the slip casting mold according to the present invention is that the slip casting mold is made of a gypsum mold to which cellulose is added, and the gypsum mold contains glue. As an additional note, the slip casting mold of the present invention is a gypsum mold containing flaky cellulose, which is used to cast and shape a slip containing ceramic powder, for example. It is added. Next, the concept behind the present invention will be described. The reason why a small amount of glue is added to a gypsum mold containing cellulose is that the addition of glue increases the initial strength of the mold and significantly improves the disintegration of the mold after heating operation. It is more preferable that the cellulose contained has water-absorbing properties as well as water-insoluble properties. In the present invention, preferred water-absorbing cellulose is one cut into short pieces. The reason for this is that the molding material has better fluidity when it is shaped into pieces. Papers made from cellulose may also be used, and in this case, tissue paper is preferred from the viewpoint of water absorption and water insolubility.
It is used by making it into pieces and uniformly dispersing it in the gypsum slurry. The reason why cellulose and glue are included in the plaster mold is that the initial strength of the mold is increased by adding glue, and the slip molded product after casting is heated together with the core to burn out the cellulose and glue, increasing the caking strength of the mold. This is to reduce the initial strength of the mold to near zero. Furthermore, if the substance mixed with gypsum is water-soluble, such a substance will be filled between the gypsum particles, resulting in a significant drop in water absorption, but cellulose does not cause this problem because it is water-insoluble. The reason why water-absorbing cellulose is contained in the plaster mold is to increase the water-absorbing effect of the mold from the slip and shorten the solidification time of the slip. The amount of glue added to a plaster mold containing 2 to 30 parts by weight of cellulose to 100 parts by weight of plaster is
The amount is preferably 0.2 to 1.0 parts by weight. If the amount added is less than 0.05 parts by weight, the effect of adding glue will hardly be seen, that is, the initial strength of the mold will remain small at less than 4 kg/cm 2 , so it will be easily damaged during slip casting and difficult to handle. , residual compressive strength after heating (hereinafter referred to as "residual strength")
This is because the mold is rather large and difficult to remove. In addition, if the amount of glue added is 2.00 parts by weight or more,
Adding glue causes a significant delay in the curing time of the gypsum mold, making it completely unusable. Therefore, the appropriate amount of glue to be added is 0.05 to 2.00 parts by weight per 100 parts by weight of gypsum. In order to obtain the mold of the present invention, the steps from slip casting to firing of the molded body are as follows: Slip casting → Disappearance of cellulose and glue in the mold (core) by heating → Collapse and removal of the mold → Creation of the molded body It is carried out in sequence of firing. The formed mold is heated at 80°C for about 4 hours to make it sufficiently dry and suitable for absorbing moisture in the slip. Since glue is added, it has sufficient initial strength compared to the case without the addition. The heating temperature for burning off the cellulose and glue may be around 500°C, and the gypsum mold will not lose its cohesive strength due to the burning off of the cellulose and glue.
Easily disintegrates under external force of 0.2Kg/cm 2 or less. Therefore, the external force is preferably, for example, extremely weak compressed air or vacuum suction, which allows disintegration and stripping to be performed simultaneously. By removing the plaster mold (core), an unfired molded body (semi-finished product) is produced, and by subsequent firing, a complete molded body, such as ceramic or metal, is obtained. [Embodiments of the Invention] Specific examples will be described below. Example 1 Firstly, flaky cellulose, glue and water were added to plaster.
They were added in the proportions shown in the table and kneaded for 5 minutes at 200 rpm.
【表】
混練して得られた鋳型スラリーを木型に注入し
てφ50×H50の試験片を作り、マツフル炉で80〜
800℃の温度で60分間加熱した。加熱後、試験片
を取り出し空中放冷後の残留強度を測定した。そ
の結果を第１図に示す。
第１図は、本発明の一実施例および従来のスリ
ツプ・キヤステイング用鋳型の加熱温度と残留強
度との関係を示す線図で、横軸に加熱温度（℃×
60分）、縦軸に残留圧縮強度（Kg/cm2）をとつてい
る。図中の曲線１は、ニカワ無添加のもの、曲線
２は、ニカワを0.2重量部添加したものである。
図から明らかなように、ニカワを添加すると湿
態強度は全く同じであるにも拘らず、初期強度
（80℃×４時間加熱後の強度）は20％向上する。
その反面、400℃以上加熱した後の残留強度は、
無添加の場合より低くなつている。400℃に例を
とると、ニカワ無添加の場合の残留強度は１Kg/
cm2であるのに対し、ニカワを0.2重量部添加する
と0.2Kg/cm2と、実に１／５の値となる。
したがつて、ニカワを添加すると無添加の場合
にくらべて、スリツプ・キヤステイング用中子の
崩壊・除去は極めて容易であることがわかる。
実施例 ２
石膏に片状セルロース、ニカワ、および水を第
２表に示す割合で添加し、200rpmで５分間混練
した。[Table] Inject the mold slurry obtained by kneading into a wooden mold to make a test piece of φ50 x H50, and heat it in a Matsufuru furnace for 80~
Heated at a temperature of 800°C for 60 minutes. After heating, the test piece was taken out and the residual strength after cooling in the air was measured. The results are shown in FIG. FIG. 1 is a diagram showing the relationship between heating temperature and residual strength of an embodiment of the present invention and a conventional slip casting mold.
60 minutes), and the residual compressive strength (Kg/cm 2 ) is plotted on the vertical axis. Curve 1 in the figure shows the product without glue added, and curve 2 shows the product with 0.2 parts by weight of glue added. As is clear from the figure, when glue is added, the initial strength (strength after heating at 80°C for 4 hours) increases by 20%, although the wet strength is exactly the same.
On the other hand, the residual strength after heating over 400℃ is
It is lower than the case without additives. Taking an example at 400℃, the residual strength without glue is 1Kg/
cm2 , when 0.2 parts by weight of glue is added, the value becomes 0.2Kg/ cm2 , which is actually 1/5. Therefore, it can be seen that the addition of glue makes it much easier to disintegrate and remove the core for slip casting than when no glue is added. Example 2 Cellulose flakes, glue, and water were added to gypsum in the proportions shown in Table 2, and the mixture was kneaded at 200 rpm for 5 minutes.
以上述べたように、本発明によれば、鋳型の初
期強度をあげるとともに、加熱操作後の鋳型の崩
壊性を格段に向上し、いかなる複雑な形状の中子
であつても、その除去が容易なスリツプ・キヤス
テイング用鋳型を提供することができる。
As described above, according to the present invention, the initial strength of the mold is increased, the collapsibility of the mold after heating operation is significantly improved, and even if the core has a complex shape, it can be easily removed. It is possible to provide a mold for slip casting.
第１図は、本発明の一実施例および従来のスリ
ツプ・キヤステイング用鋳型の加熱温度と残留強
度との関係を示す線図、第２図は、本発明の一実
施例に係るスリツプ・キヤステイング用鋳型にお
けるニカワの添加量と残留強度および初期強度と
の関係を示す線図である。
FIG. 1 is a diagram showing the relationship between heating temperature and residual strength of a slip casting mold according to an embodiment of the present invention and a conventional slip casting mold, and FIG. FIG. 2 is a diagram showing the relationship between the amount of glue added and residual strength and initial strength in a staining mold.
Claims (1)
ツプ・キヤステイング用鋳型において、前記石膏
鋳型をニカワを含有するものとしたことを特徴と
するスリツプ・キヤステイング用鋳型。 ２ 石膏：100重量部に対し、セルロース：２〜
20重量部、ニカワ：0.2〜1.0重量部を含有するこ
とを特徴とする特許請求の範囲第１項記載のスリ
ツプ・キヤステイング用鋳型。[Scope of Claims] 1. A slip casting mold comprising a gypsum mold to which cellulose is added, characterized in that the gypsum mold contains glue. 2 Gypsum: 100 parts by weight, cellulose: 2~
20 parts by weight of glue and 0.2 to 1.0 parts by weight of glue, the mold for slip casting according to claim 1.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16812083A JPS6061136A (en) | 1983-09-14 | 1983-09-14 | Casting mold for slip casting |
| KR1019840001943A KR900000030B1 (en) | 1983-04-15 | 1984-04-12 | Slip casting mold |
| US06/599,483 US4604141A (en) | 1983-04-15 | 1984-04-12 | Slip casting mold |
| DE19843414096 DE3414096A1 (en) | 1983-04-15 | 1984-04-13 | SLICK ENERGY FORM |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16812083A JPS6061136A (en) | 1983-09-14 | 1983-09-14 | Casting mold for slip casting |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6061136A JPS6061136A (en) | 1985-04-08 |
| JPH0157642B2 true JPH0157642B2 (en) | 1989-12-06 |
Family
ID=15862216
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16812083A Granted JPS6061136A (en) | 1983-04-15 | 1983-09-14 | Casting mold for slip casting |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6061136A (en) |
-
1983
- 1983-09-14 JP JP16812083A patent/JPS6061136A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6061136A (en) | 1985-04-08 |
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