JP2000219565A - Forming of gypsum material - Google Patents
Forming of gypsum materialInfo
- Publication number
- JP2000219565A JP2000219565A JP1997299A JP1997299A JP2000219565A JP 2000219565 A JP2000219565 A JP 2000219565A JP 1997299 A JP1997299 A JP 1997299A JP 1997299 A JP1997299 A JP 1997299A JP 2000219565 A JP2000219565 A JP 2000219565A
- Authority
- JP
- Japan
- Prior art keywords
- gypsum
- slurry
- time
- mold
- gypsum slurry
- 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.)
- Pending
Links
- 229910052602 gypsum Inorganic materials 0.000 title claims abstract description 156
- 239000010440 gypsum Substances 0.000 title claims abstract description 156
- 239000000463 material Substances 0.000 title claims abstract description 49
- 239000002002 slurry Substances 0.000 claims abstract description 40
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 30
- 239000002245 particle Substances 0.000 claims abstract description 20
- HELHAJAZNSDZJO-OLXYHTOASA-L sodium L-tartrate Chemical compound [Na+].[Na+].[O-]C(=O)[C@H](O)[C@@H](O)C([O-])=O HELHAJAZNSDZJO-OLXYHTOASA-L 0.000 claims abstract description 5
- 239000001509 sodium citrate Substances 0.000 claims abstract description 5
- NLJMYIDDQXHKNR-UHFFFAOYSA-K sodium citrate Chemical compound O.O.[Na+].[Na+].[Na+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O NLJMYIDDQXHKNR-UHFFFAOYSA-K 0.000 claims abstract description 5
- 239000001433 sodium tartrate Substances 0.000 claims abstract description 5
- 229960002167 sodium tartrate Drugs 0.000 claims abstract description 5
- 235000011004 sodium tartrates Nutrition 0.000 claims abstract description 5
- 238000000034 method Methods 0.000 claims description 23
- 238000000465 moulding Methods 0.000 claims description 14
- 238000001556 precipitation Methods 0.000 claims description 10
- 238000002156 mixing Methods 0.000 abstract description 6
- 238000004062 sedimentation Methods 0.000 abstract 2
- 238000005266 casting Methods 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 4
- 239000011159 matrix material Substances 0.000 description 4
- 238000005259 measurement Methods 0.000 description 3
- 239000011505 plaster Substances 0.000 description 3
- 230000002035 prolonged effect Effects 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 230000002087 whitening effect Effects 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/14—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing calcium sulfate cements
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/00034—Physico-chemical characteristics of the mixtures
- C04B2111/00068—Mortar or concrete mixtures with an unusual water/cement ratio
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
- C04B2111/00939—Uses not provided for elsewhere in C04B2111/00 for the fabrication of moulds or cores
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
Description
【０００１】[0001]
【利用分野】本発明は，硬度が要求される石膏材の成形
方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a gypsum material requiring hardness.
【０００２】[0002]
【従来技術】石膏は，自動車や航空機などのモデルチェ
ンジなどの際に，ならいモデルや反転モデル，鋳造用砂
込め型，中子型などに用いられている。石膏は，一般的
にアルカリ性石膏の他に，アルカリ性低膨張石膏，樹脂
混合石膏，中性模型型用石膏，高膨張石膏などがあり，
これらは用途に応じて適宜選択して使用される。アルカ
リ性低膨張石膏は，精密な模型を鋳造する場合に使用さ
れる。ここで要求される性能は，硬化時の膨張が小さい
こと，型の表面硬度が大きいこと，長期安定性である。2. Description of the Related Art Gypsum is used as a follow-up model, a reversal model, a sand-filling mold for casting, a core mold, and the like when changing the model of an automobile or an aircraft. Gypsum generally includes, in addition to alkaline gypsum, alkaline low-expansion gypsum, resin-mixed gypsum, gypsum for a neutral model, and high-expansion gypsum.
These are appropriately selected and used according to the application. Alkaline low expansion gypsum is used for casting precision models. The performance required here is that the expansion during curing is small, the surface hardness of the mold is large, and long-term stability.
【０００３】樹脂混合石膏は，主に，ならいモデル，一
般削り出しモデルの用途がある。ここで要求される性能
は，表面硬度が大きいことである。中性模型型用石膏
は，主に手作業の工程を含み，手が荒れるなどの理由で
アルカリが使用できない場合に使われる。高膨張石膏
は，主に原寸模型または現物から縮みしろを見込んで設
計する場合に使用される。ここで要求される性能は，安
定して高い膨張を有することである。[0003] Resin-mixed gypsum is mainly used as a copy model or a general cut-out model. The performance required here is that the surface hardness is high. Gypsum for a neutral model is mainly used when a hand process is involved and alkalis cannot be used because of rough hands. High-expansion gypsum is mainly used when designing with an allowance for shrinkage from a full-scale model or actual product. The performance required here is to have a stable and high expansion.
【０００４】そして，各種石膏に要求される性能を満た
すために，種々の改良が行われている。例えば，硬化時
の膨張を小さくするために，セメントなどの膨張低下剤
を添加したり，表面硬度を硬くするために，樹脂を多く
添加することが行われている。これらの改良方法は，混
水量が７０重量％以下と比較的少ない場合には良好であ
る。[0004] Various improvements have been made to satisfy the performance required for various types of gypsum. For example, an expansion reducing agent such as cement is added to reduce the expansion during hardening, and a large amount of resin is added to increase the surface hardness. These improved methods are good when the amount of water mixture is relatively small, such as 70% by weight or less.
【０００５】[0005]
【解決しようとする課題】しかし，複雑な形状の石膏材
や大型の石膏材を成形する場合には，成形型全体に石膏
スラリーが行き渡るように粘性を低くすることが必要と
され，そのためには，比較的低い粘度の混水量７０重量
％以上の石膏スラリーを用いる必要がある。そのため，
上記従来の改良方法による効果は十分に発揮されず，水
溶性樹脂の析出による表面荒れ，即ち白華現象が生じる
など，物性面で問題があった。またコスト面で添加量に
制限があった。However, when molding a gypsum material of a complicated shape or a large gypsum material, it is necessary to lower the viscosity so that the gypsum slurry can be spread over the entire molding die. It is necessary to use a gypsum slurry having a relatively low viscosity and a water content of 70% by weight or more. for that reason,
The effect of the above-mentioned conventional improvement method is not sufficiently exhibited, and there are problems in physical properties such as surface roughness due to precipitation of the water-soluble resin, that is, occurrence of a whitening phenomenon. In addition, the amount added was limited in terms of cost.
【０００６】本発明はかかる従来の問題点に鑑み，混水
量が多い石膏スラリーであっても硬化時の膨張が少なく
かつ硬度が高い，石膏材の成形方法を提供しようとする
ものである。The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a method for forming a gypsum material, which has a small expansion during curing and a high hardness even when the gypsum slurry contains a large amount of water.
【０００７】[0007]
【課題の解決手段】本発明は, 硬度が要求される石膏材
を成形する成形方法において，混水量７０〜９０重量％
の石膏スラリーを調製し，該石膏スラリーを成形型内に
流し込み，石膏の沈殿を促進させることを特徴とする石
膏材の成形方法である。According to the present invention, there is provided a molding method for molding a gypsum material requiring hardness, wherein a mixed water content is 70 to 90% by weight.
Gypsum slurry is prepared, and the gypsum slurry is poured into a molding die to accelerate the precipitation of gypsum.
【０００８】混水量とは，乾燥石膏に対する水の重量比
をいう。石膏スラリーの混水量が７０重量％未満の場合
には，コストが高くなり，また大型の石膏材を成形しに
くくなる場合がある。また，９０重量％を超える場合に
は，成形した石膏材の強度が低下する場合がある。[0008] The amount of water mixed means the weight ratio of water to dry gypsum. If the amount of water in the gypsum slurry is less than 70% by weight, the cost may be high, and it may be difficult to form a large gypsum material. If it exceeds 90% by weight, the strength of the formed gypsum material may decrease.
【０００９】次に，本発明の作用を説明する。石膏材
は，水と混和して石膏スラリーとした直後から硬化反応
が始まり，流込み作業中でも硬化反応は進行し続け，粘
性が徐々に増加する性質を有する。本発明においては，
混水量が７０％以上の石膏スラリーを用いている。かか
る石膏スラリーは比較的粘性が低く，成形型内全体へ行
き渡りやすく成形性がよい。そのため，大型の石膏用成
形型に石膏スラリーを流し込むときのように流し込みに
長い時間が必要な場合にも，成形性のよい石膏材を成形
することができる。また，成形コストを低くすることが
できる。Next, the operation of the present invention will be described. The setting reaction of the gypsum material starts immediately after it is mixed with water to form a gypsum slurry, and the setting reaction continues to progress even during the pouring operation, and the viscosity gradually increases. In the present invention,
A gypsum slurry having a water content of 70% or more is used. Such a gypsum slurry has a relatively low viscosity and is easy to spread throughout the entire mold, and has good moldability. Therefore, even when a long time is required for casting, such as when a gypsum slurry is poured into a large gypsum mold, a plaster material having good moldability can be formed. Also, the molding cost can be reduced.
【００１０】また，本発明においては，石膏スラリーを
成形型内に流し込んだ後，石膏の沈殿を促進させてい
る。これにより，石膏の底部の密度が高くなる。そのた
め，石膏材の底部の膨張を抑制し表面硬度を硬くするこ
とができる。したがって，石膏材において硬度が要求さ
れる部位を成形型の底部で成形することとすれば，石膏
の任意な部位の表面硬度を硬くすることができる。In the present invention, after the gypsum slurry is poured into the mold, the precipitation of the gypsum is promoted. This increases the density at the bottom of the gypsum. Therefore, expansion of the bottom of the gypsum material can be suppressed, and the surface hardness can be increased. Therefore, if a portion of the gypsum material requiring hardness is formed at the bottom of the mold, the surface hardness of an arbitrary portion of the gypsum can be increased.
【００１１】本発明の詳細について説明する。石膏の沈
殿を促進させる手段として，たとえば，硬化遅延剤を添
加して硬化時間を遅くする方法，比較的大きな粒径の石
膏を用いる方法，石膏スラリーの混水量を高くする方法
などがある。The details of the present invention will be described. Means for promoting gypsum precipitation include, for example, a method of adding a setting retarder to delay the setting time, a method of using gypsum having a relatively large particle size, and a method of increasing the amount of mixed gypsum slurry.
【００１２】硬化遅延剤を添加する方法 たとえば，上記石膏スラリーには，酒石酸ナトリウムま
たは／及びクエン酸ナトリウムを添加することが好まし
く，その添加量は，石膏スラリー１００重量％のうち
０．０１〜０．１重量％であることが好ましい。これに
より，石膏の硬化が遅延し，石膏の沈殿を促進させるこ
とができる。上記添加剤が０．０１重量％未満の場合に
は，石膏の沈殿が促進されないおそれがある。また，
０．１重量％を超える場合には，石膏が硬化し難く，硬
化時間が遅くなることによる作業効率の悪化，沈殿が促
進されすぎて石膏材上層に水層が形成されるおそれがあ
る。Method of adding a setting retarder For example, it is preferable to add sodium tartrate and / or sodium citrate to the above-mentioned gypsum slurry, and the amount of addition is 0.01 to 0% of 100% by weight of the gypsum slurry. 0.1% by weight. Thereby, the hardening of the gypsum is delayed, and the precipitation of the gypsum can be promoted. If the amount of the additive is less than 0.01% by weight, precipitation of gypsum may not be promoted. Also,
If the amount exceeds 0.1% by weight, the gypsum is hardly hardened, and the working time is deteriorated due to a slow hardening time, and the precipitation is promoted too much, and an aqueous layer may be formed on the gypsum material.
【００１３】比較的大きな粒径の石膏を用いる方法 例えば，上記石膏は，粒径が１００μｍ以上の石膏粒子
を３〜７％含むことが好ましい。かかる比較的大きな石
膏粒子は，石膏スラリーの流込み後に，沈殿しやすい。
また，成形型内における石膏材の上層に水層が形成され
ることを抑制する。また，沈殿時間が長くなっても水層
が形成されることを抑制する。そのため，設計形状通り
の石膏材を成形することができる。また，石膏材の強度
も高くなる。一方，粒径が１００μｍ以上の粒子が３％
未満の場合には，石膏材の表面硬度が悪化するおそれが
ある。また，７％を超える場合には，石膏材の上層に水
層が形成されやすくなり，またこのため型の側面部位に
強度のバラツキが生じるおそれがある。Method using gypsum having a relatively large particle size For example, the gypsum preferably contains 3 to 7% of gypsum particles having a particle size of 100 μm or more. Such relatively large gypsum particles tend to settle after the gypsum slurry is poured.
Further, formation of an aqueous layer on the gypsum material in the molding die is suppressed. Also, the formation of an aqueous layer is suppressed even if the precipitation time is long. Therefore, it is possible to form a plaster material according to the design shape. Further, the strength of the gypsum material also increases. On the other hand, 3% of particles having a particle size of 100 μm or more
If it is less than 1, the surface hardness of the gypsum material may deteriorate. On the other hand, if it exceeds 7%, a water layer is likely to be formed on the upper layer of the gypsum material, and there is a possibility that a variation in strength occurs on the side surface of the mold.
【００１４】上記石膏スラリーに含まれている石膏の硬
化時間は３０分以上であることが好ましい。３０分未満
の場合には，底部への石膏の沈殿が不十分となり石膏材
の表面硬度を硬くすることができないおそれがある。ま
た，上記石膏スラリーに含まれている石膏の硬化時間
は，４０分以下であることが好ましい。４０分を越える
場合には，石膏材上部に水層が形成されて作業性が低下
したり，硬化時間が長くなり作業効率が低下するおそれ
がある。ここで，石膏の硬化時間とは，水と石膏とを混
合した時点から石膏が見掛け上完全に硬化するまでの時
間をいう。The setting time of the gypsum contained in the gypsum slurry is preferably 30 minutes or more. If the time is less than 30 minutes, the precipitation of gypsum on the bottom becomes insufficient and the surface hardness of the gypsum material may not be hardened. The setting time of the gypsum contained in the gypsum slurry is preferably 40 minutes or less. If the time exceeds 40 minutes, a water layer may be formed on the gypsum material and workability may be reduced, or the curing time may be prolonged and work efficiency may be reduced. Here, the setting time of the gypsum refers to the time from when water and gypsum are mixed to when the gypsum is apparently completely hardened.
【００１５】また，石膏スラリーに含まれている石膏の
始発時間は２６〜２８分であることが好ましい。２６分
未満の場合には，石膏と水とを混和した直後から硬化反
応が始まり，成形型内全体に石膏スラリーが行き渡らず
成形性が低下するおそれがある。また，２８分を超える
場合には，石膏材上部に水層が形成されて作業性が低下
したり，硬化時間が長くなり作業効率が低下するおそれ
がある。ここに，石膏の始発時間とは，石膏と水とを混
和したときから，硬化が開始するまでの時間をいう。Further, it is preferable that the starting time of the gypsum contained in the gypsum slurry is 26 to 28 minutes. If the time is less than 26 minutes, the curing reaction starts immediately after mixing the gypsum and water, and the gypsum slurry may not spread all over the inside of the mold, and the moldability may be reduced. If the time exceeds 28 minutes, a water layer may be formed on the gypsum material to lower the workability, or the curing time may be prolonged to lower the work efficiency. Here, the initial time of gypsum refers to the time from when gypsum and water are mixed until hardening starts.
【００１６】また，石膏スラリーに含まれている石膏の
終結時間は，４０〜５５分であることが好ましい。４０
分未満の場合には，石膏と水とを混和した直後から硬化
反応が始まり，成形型内全体に石膏スラリーが行き渡ら
ず成形性が低下するおそれがある。５５分を超える場合
には，石膏材上部に水層が形成されて作業性が低下した
り，硬化時間が長くなり作業効率が低下するおそれがあ
る。ここに，終結時間とは，石膏と水とを混和したとき
から石膏の硬化が完了するまでの時間をいう。[0016] The final time of the gypsum contained in the gypsum slurry is preferably 40 to 55 minutes. 40
If it is less than 1 minute, the curing reaction starts immediately after mixing the gypsum and water, and the gypsum slurry may not spread throughout the entire mold, and the moldability may be reduced. If the time exceeds 55 minutes, a water layer may be formed on the gypsum material to lower the workability, or the hardening time may be prolonged to lower the work efficiency. Here, the term “ending time” refers to the time from when gypsum and water are mixed until the hardening of the gypsum is completed.
【００１７】[0017]
【発明の実施の形態】実施形態例１ 本発明の実施形態に係る石膏材の成形方法を，図１，図
２を用いて説明する。本例は，硬度が要求される石膏材
の流込成形方法である。まず，図１（ａ）に示すごと
く，成形しようとする石膏材の設計形状を有する母型７
を準備する。母型７は，金属または木材からなる。次
に，図１（ｂ）に示すごとく，母型７の上に枠組みを行
いその中に石膏スラリーを流し込んで，反転用石膏型６
を成形する。DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment A method for forming a gypsum material according to an embodiment of the present invention will be described with reference to FIGS. This example is a casting method of gypsum material requiring hardness. First, as shown in FIG. 1 (a), a matrix 7 having a design shape of a gypsum material to be molded.
Prepare The matrix 7 is made of metal or wood. Next, as shown in FIG. 1 (b), a framework is formed on the matrix 7 and a gypsum slurry is poured into the framework, and the reversing gypsum mold 6 is formed.
Is molded.
【００１８】次に，石膏と水とを混和して混水量が８０
重量％の石膏スラリーを調製する。石膏としては，α石
膏及びβ石膏を用いる。石膏スラリーには，石膏１００
重量部に対して，硬化遅延剤としての酒石酸ナトリウム
及びクエン酸ナトリウムが０．０１４重量部添加されて
いる。また，石膏は，粒径１００μｍ以上のものが６．
７重量％と，粒径１００μｍ以下のものが９３．３重量
％とからなる。Next, gypsum and water are mixed, and the water content is 80
Prepare a gypsum slurry by weight. As gypsum, α gypsum and β gypsum are used. Gypsum slurry contains gypsum 100
0.014 parts by weight of sodium tartrate and sodium citrate as a curing retarder are added to the parts by weight. In addition, gypsum having a particle size of 100 μm or more is used.
7% by weight and 93.3% by weight of those having a particle size of 100 μm or less.
【００１９】次いで，石膏スラリーを反転用石膏型６の
上に枠組みを行いその中に上記石膏スラリーを流し込
み，石膏材５を成形する。石膏の始発時間は２６．５
分，硬化時間は３３分，終結時間は４４分である。石膏
の終結時間が経過した後に脱型して，石膏材５を取出
す。必要に応じて石膏材を研磨，研削する。Next, the gypsum slurry is framed on the reversing gypsum mold 6, and the gypsum slurry is poured into the framework to form the gypsum material 5. The first gypsum time is 26.5
Minutes, curing time is 33 minutes and final time is 44 minutes. After the end time of the gypsum elapses, the gypsum material 5 is removed from the mold. Grind and grind the gypsum material as needed.
【００２０】以上により，本例の石膏材を得る。得られ
た石膏材５は，反転モデル３を成形するための成形型
（図１（ｄ））や，製品設計形状の試作品，即ちならい
モデル（図１（ｅ））に使用する。なお，反転モデル３
は，金属などからなる成形品４の型として用いられる
（図１（ｆ））。Thus, the gypsum material of this embodiment is obtained. The obtained gypsum material 5 is used for a molding die (FIG. 1 (d)) for molding the reversal model 3 and a prototype of a product design shape, that is, a copying model (FIG. 1 (e)). In addition, inversion model 3
Is used as a mold for a molded product 4 made of metal or the like (FIG. 1 (f)).
【００２１】本例の石膏材は，図２に示すごとく，反転
用石膏型６に対面している底部５０の石膏密度は，他の
部位５１よりも高い密度であった。石膏材５の底部５０
の表面硬度を東工大式硬度計にて測定した。東工大式硬
度計は，一定の刃形によるドリルを被測定物の面にあて
て，一定の荷重及び回転速度で回転させ，そのときに形
成された溝の直径を測定するものであり，溝の直径を表
面硬度として硬度の指標とした。本例においては，ドリ
ルによる被測定物への荷重は９００ｇであり，回転数は
２０回（４０ｒｐｍ）とした。その結果，石膏材の底部
の表面硬度は２．３５ｍｍであった。As shown in FIG. 2, in the gypsum material of this embodiment, the gypsum density of the bottom 50 facing the reversing gypsum mold 6 was higher than that of the other parts 51. The bottom 50 of the gypsum material 5
Was measured with a Tokyo Tech hardness meter. The Tokyo Tech hardness tester measures the diameter of a groove formed by applying a drill with a fixed edge to the surface of the workpiece and rotating it at a constant load and rotational speed. Was used as an index of hardness as the surface hardness. In this example, the load on the object to be measured by the drill was 900 g, and the number of revolutions was 20 times (40 rpm). As a result, the surface hardness at the bottom of the gypsum material was 2.35 mm.
【００２２】次に，石膏材の膨張率を測定した。測定に
は，（株）丸菱科学機械製作所の石膏膨張率測定器ＧＷ
−２００を使用した。測定方法は石膏を水に投入して５
分攪拌した後，測定器にスラリーを流し込み，始発時間
より膨張率の測定を開始し終結時間に達したときの膨張
率を測定するというものである。測定の結果，石膏材の
膨張率は０．０８％であった。Next, the expansion coefficient of the gypsum material was measured. For the measurement, the gypsum expansion coefficient measuring device GW of Marubishi Scientific Machinery Co., Ltd.
-200 was used. The measuring method is as follows.
After stirring for a minute, the slurry is poured into the measuring instrument, and the measurement of the expansion rate is started from the first time, and the expansion rate when the end time is reached is measured. As a result of the measurement, the expansion rate of the gypsum material was 0.08%.
【００２３】実施形態例２ 本例においては，混水量，石膏の粒径分布を変え，また
硬化遅延剤の添加量により硬化時間及び終結時間を変え
て，種々の石膏材を成形した。硬化遅延剤としては酒石
酸ナトリウムまたは／及びクエン酸ナトリウムを用い
た。成形方法の他の点については実施形態例１と同様で
ある。石膏材の膨張率及び表面硬度を実施形態例１と同
様に測定し，表１に示した。Embodiment 2 In this embodiment, various gypsum materials were formed by changing the amount of mixed water and the particle size distribution of gypsum, and changing the hardening time and the finishing time by adding the hardening retarder. Sodium tartrate and / or sodium citrate were used as a curing retarder. The other points of the molding method are the same as in the first embodiment. The expansion coefficient and surface hardness of the gypsum material were measured in the same manner as in Example 1, and are shown in Table 1.
【００２４】同表より，試料１，２は，混水量がいずれ
も８０％であり，粒径１００μｍ以上の石膏粒子が３．
０重量％，６．７重量％であり，硬化時間がいずれも３
３分であり，終結時間が４０分，５５分である。試料
１，２は，膨張率が小さく，かつ優れた表面硬度を有し
ていた。As shown in the table, Samples 1 and 2 each contained 80% of mixed water and had gypsum particles having a particle diameter of 100 μm or more.
0% by weight and 6.7% by weight.
3 minutes and the end time is 40 minutes and 55 minutes. Samples 1 and 2 had a small expansion coefficient and excellent surface hardness.
【００２５】一方，試料Ｃ１は混水量が６０％と低く，
膨張率が高かった。試料Ｃ２は，試料Ｃ１を混水量８０
％で混練した場合であり，表面硬度が小さかった。試料
Ｃ３，Ｃ４は硬化遅延剤未添加であり，試料１，２より
も表面硬度が劣化していた。試料Ｃ５〜Ｃ８は粒径１０
０μｍの石膏粒子が１．３％，７．５％であり，試料
１，２に比べて表面硬度が劣っていた。On the other hand, the sample C1 has a low mixed water content of 60%.
The expansion rate was high. The sample C2 was prepared by mixing the sample C1 with a mixed water amount of 80.
%, And the surface hardness was small. Samples C3 and C4 had no curing retarder added and had a lower surface hardness than Samples 1 and 2. Samples C5 to C8 have a particle size of 10
The gypsum particles of 0 μm were 1.3% and 7.5%, and the surface hardness was inferior to Samples 1 and 2.
【００２６】以上より，混水量が６０〜８０％であり，
粒径１００μｍ以上の石膏粒子を３〜７％含み，また硬
化遅延剤が添加されている石膏スラリーを用いて流し込
み成形することにより底部の硬度が高く膨張の少ない石
膏材を得ることができることがわかる。From the above, the mixed water amount is 60 to 80%,
It can be seen that a gypsum material having high bottom hardness and little expansion can be obtained by casting using a gypsum slurry containing 3 to 7% of gypsum particles having a particle diameter of 100 μm or more and having a setting retarder added. .
【００２７】[0027]
【表１】 [Table 1]
【００２８】[0028]
【発明の効果】本発明によれば，混水量が多い石膏スラ
リーであっても硬化時の膨張が少なくかつ表面硬度が高
い，石膏材の成形方法を提供することができる。According to the present invention, it is possible to provide a method for molding a gypsum material having a small expansion during curing and a high surface hardness even with a gypsum slurry containing a large amount of water.
【図１】実施形態例１の石膏材の成形方法を示す説明
図。FIG. 1 is an explanatory view showing a method for forming a gypsum material of a first embodiment.
【図２】実施形態例１の石膏材の断面図。FIG. 2 is a cross-sectional view of the gypsum material of the first embodiment.
７．．．母型， ６．．．反転用石膏型， ５．．．石膏材， ５０．．．底部， ５１．．．他の部位， 7. . . Matrix, 6. . . 4. Plaster mold for inversion, . . Gypsum material, 50. . . Bottom, 51. . . Other parts,
Claims (4)
方法において，混水量７０〜９０重量％の石膏スラリー
を調製し，該石膏スラリーを成形型内に流し込み，石膏
の沈殿を促進させることを特徴とする石膏材の成形方
法。In a molding method for molding a gypsum material requiring hardness, a gypsum slurry having a water content of 70 to 90% by weight is prepared, and the gypsum slurry is poured into a molding die to promote gypsum precipitation. A method for forming a gypsum material, characterized by the following.
含まれている石膏の硬化時間は３０分以上であることを
特徴とする石膏材の成形方法。2. The method for forming a gypsum material according to claim 1, wherein the setting time of the gypsum contained in the gypsum slurry is 30 minutes or more.
ラリーには，酒石酸ナトリウムまたは／及びクエン酸ナ
トリウムが添加されていることを特徴とする石膏材の成
形方法。3. The method for forming a gypsum material according to claim 1, wherein said gypsum slurry is added with sodium tartrate and / or sodium citrate.
上記石膏は，粒径が１００μｍ以上の石膏粒子を３〜７
％含むことを特徴とする石膏材の成形方法。4. The method according to claim 1, wherein:
The gypsum contains gypsum particles having a particle size of 100 μm or more in a range of 3 to
%. A method for forming a gypsum material characterized by containing:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1997299A JP2000219565A (en) | 1999-01-28 | 1999-01-28 | Forming of gypsum material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1997299A JP2000219565A (en) | 1999-01-28 | 1999-01-28 | Forming of gypsum material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2000219565A true JP2000219565A (en) | 2000-08-08 |
Family
ID=12014120
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1997299A Pending JP2000219565A (en) | 1999-01-28 | 1999-01-28 | Forming of gypsum material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2000219565A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102531513A (en) * | 2011-12-28 | 2012-07-04 | 刘立文 | Ceramic-reinforced tyre casting gypsum powder and preparation process thereof |
| CN113799232A (en) * | 2021-07-30 | 2021-12-17 | 安徽省含山民生瓷业有限责任公司 | Model manufacturing process |
-
1999
- 1999-01-28 JP JP1997299A patent/JP2000219565A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102531513A (en) * | 2011-12-28 | 2012-07-04 | 刘立文 | Ceramic-reinforced tyre casting gypsum powder and preparation process thereof |
| CN113799232A (en) * | 2021-07-30 | 2021-12-17 | 安徽省含山民生瓷业有限责任公司 | Model manufacturing process |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5378279A (en) | Enhanced cement mixed with selected aggregates | |
| JP2000219565A (en) | Forming of gypsum material | |
| JP7762038B2 (en) | Method for measuring the amount of expansion of hydraulically hardened concrete and method for estimating the amount of restrained expansion of expansive concrete | |
| JPS58115051A (en) | Admixture for underwater concrete | |
| JPH1192202A (en) | Production of inorganic hardened molded form | |
| JP7569039B2 (en) | Cement Composition | |
| JP3731854B2 (en) | Method for producing concrete composition | |
| JP3606828B2 (en) | Ceramic mold and its manufacturing method | |
| JPS58120554A (en) | Cement group self-levelling floor material | |
| US5164004A (en) | High permeability metal casting plaster and method of making same | |
| JP2002248615A (en) | Method for manufacture of concrete wherein ratio of entrained air is raised | |
| JPS61191550A (en) | Quick-setting non-shrink grout material | |
| JPH03221238A (en) | Method for coating foamed resin pattern | |
| JPS6172664A (en) | Admixing agent for underwater concrete | |
| JPS6150900B2 (en) | ||
| JP2922196B1 (en) | Resin concrete segment and method of manufacturing the same | |
| JP3992116B2 (en) | Method for producing high fluidity glass fiber reinforced cement sheet | |
| JPS60127256A (en) | Plaster composition | |
| US5176195A (en) | High permeability metal casting plaster and method of making same | |
| JPS5858206B2 (en) | Manufacturing method of high strength mortar and concrete | |
| JP6175362B2 (en) | Method for manufacturing concrete structure | |
| JP2923846B2 (en) | Evaluation method of material separation of high fluidity concrete | |
| US20160015605A1 (en) | Dental gypsum powder | |
| JPS61186145A (en) | Casting master die | |
| JPS63218529A (en) | Rust preventive agent for lightweight cellular concrete reinforcement reinforcing bars |