JPS6123057B2 - - Google Patents

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Publication number
JPS6123057B2
JPS6123057B2 JP52037596A JP3759677A JPS6123057B2 JP S6123057 B2 JPS6123057 B2 JP S6123057B2 JP 52037596 A JP52037596 A JP 52037596A JP 3759677 A JP3759677 A JP 3759677A JP S6123057 B2 JPS6123057 B2 JP S6123057B2
Authority
JP
Japan
Prior art keywords
mold
gas
added
binder
molding sand
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
Application number
JP52037596A
Other languages
Japanese (ja)
Other versions
JPS53127324A (en
Inventor
Tetsuo Nakazawa
Junji Sakai
Shogo Morimoto
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
Priority to JP3759677A priority Critical patent/JPS53127324A/en
Publication of JPS53127324A publication Critical patent/JPS53127324A/en
Publication of JPS6123057B2 publication Critical patent/JPS6123057B2/ja
Granted legal-status Critical Current

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  • Mold Materials And Core Materials (AREA)

Description

【発明の詳細な説明】[Detailed description of the invention]

本発明は鋳造用の鋳型の製作方法に関するもの
である。従来から実用化されている金属鋳造用鋳
型には、けい酸ソーダのような無機粘結剤を使用
したものと、フエノール樹脂、フラン樹脂その他
の有機粘結剤を使用したものがある。これらの鋳
型は、いずれも溶融金属の鋳込み時の圧力あるい
は熱に耐え得る性質を有している。しかし、前者
は鋳込み後の鋳型の崩壊性が悪いため、鋳物を取
り出す操作が非常に困難で鋳物製造工数が嵩む。
有機粘結剤を使用する鋳型は、このような問題点
はない。鋳型の硬化方法としては、鋳型砂中に添
加した粘結剤成分の化学反応による硬化と粘結剤
を添加した鋳型砂を膜型に充填した後、CO2ガス
あるいはアミン系ガスを鋳型中に吹き込んで鋳型
を硬化させるものなどがある。鋳型の硬化方法と
して、前者は、鋳型砂に粘結剤を添加すると同時
に化学反応が開始されるため、鋳型砂を有効に利
用できる時間いわゆる可使時間に制限がある。後
者の方法には例えばけい酸ソーダを粘結剤とする
鋳型砂にCO2ガスを吹き込んで硬化させる、いわ
ゆるCO2プロセスあるいは水酸基含有樹脂(例え
ばフエノール樹脂)とポリイソシアネートを粘結
剤とする鋳型砂にアミンガスを吹き込んで硬化さ
せるもの、さらにアクリル系共重合体あるいはフ
エノール系樹脂と水酸化カルシウムとを組合せた
ものをCO2ガスで硬化させるものなどがある。こ
れらの硬化方法は、前述した鋳型砂中の粘結剤成
分の化学反応によるものよりも鋳型砂の可使時間
を長くでき、しかもガスを吹き込むと直ちに鋳型
が硬化するため、鋳型の生産効率を高めることが
できる。しかし、CO2プロセスはけい酸ソーダを
粘結剤としているため鋳型の崩壊性に難点があ
り、またアミンガスを用いるものは、アミンガス
の毒性および臭気の点で問題がある。またアクリ
ル酸エステルとアクリル酸アンモンならびにアク
リル酸ナトリウムとの共重合体と水酸化カルシウ
ムとを組合せてCO2ガスで硬化したものは、(1)鋳
型砂の調製時あるいは造型時にアンモニアガスが
出て作業環境を悪化させる、(2)CO2ガス吹き込み
直後の強度が不足する、等の問題点がある。さら
にフエノール樹脂を用いるものはアンモニアガス
の発生等による作業環境の汚染はないがCO2ガス
吹き込み後の鋳型の硬化は乾燥のみのため鋳型の
強度上昇が少ない。 さらに発明者らは、以前に以上述べた従来技術
であるCO2プロセスあるいはその他の鋳型の問題
点を改善する技術として、ポリビニルアルコール
と水酸化カルシウムあるいは酸化カルシウムおよ
びCO2ガスの組合せよりなる鋳型の製作方法を提
案した。これは従来技術を大幅に改善できる特徴
を有するが、大型の鋳型を製作する場合、鋳型内
部まで均一に硬化させにくいものであつた。 本発明は以上説明した従来技術の利点を生か
し、問題点を改善した鋳型の製作方法を提供する
ものである。具体的には、(1)鋳型の崩壊性が良好
であり、(2)有毒、悪臭物質を含まない、(3)生産効
率の良好な鋳型製作方法の提供である。 本発明で提供する鋳型の製作方法は、CO2プロ
セスの利点、有機粘結剤を使用する鋳型の利点を
兼備したものである。以下に本発明の材料を構成
する成分について詳細に説明する。 本発明で用いる重合体は、スチレン−無水マレ
イン酸共重合体、メチルビニルエーテル−無水マ
レイン酸共重合体である。これらの重合体は水に
溶解する際、苛性アルカリを必要とし、これによ
つて重合体のカルボキシル基とNa、K等のアル
カリ金属とが中和結合し水に溶解する。苛性アル
カリの代りにMg(OH)2、アンモニア、アミンな
どでも水に溶解するが、CO2ガスを吹付けずに常
温で硬化し、またアンモニアガスが発生して作業
環境を悪くする。故に不適当である。 本発明においてCa(OH)2またはCaOはそれぞ
れ1種で用いることができるが、これらを同時に
用いてもよい。 これらのCa(OH)2またはCaOは重合体に対し
800%以下、好ましくは300%以下で使用すること
が好ましい。鋳型粘結剤の成分として使用する方
法は、前もつてこれらを重合体の水溶液中にサス
ペンシヨンさせておいて使用してもよいし、単独
で耐火物粒子中に添加してもよい。 また重合体水溶液あるいはこれにCa(OH)2
たはCaOをサスペンシヨンさせた水溶液は、鋳型
粘結剤として用いる場合、木粉または各種のエマ
ルジヨン、ラテツクスなどを添加し、その添加量
に応じて粘結力を向上させたり、粘度を調節する
ことができる。 このようにして作つた粘結剤は次の(A)、(B)2通
りの形態で包装される。 (A) 第1成分:重合体の苛性アルカリ中和水溶
液、第2成分:Ca(OH)2またはCaO。 (B) 第1成分:重合体の苛性アルカリ中和水溶液
にCa(OH)2またはCaOをサスペンシヨンさせ
たもの。 このようにして包装されて提供された粘結剤
は、(A)タイプのものは耐火物粒子に2つの成分を
それぞれ添加混合し、また(B)タイプのものは第1
成分のみを添加混合して鋳型砂を得る。この鋳型
砂は、模型に充填した後、CO2ガスを吹き込むと
直ちに鋳型が硬化し、鋳造用鋳型として利用でき
る。CO2ガスを吹き込まないで密閉しておくと鋳
型砂は硬化せず、長時間保存しておくことができ
る。本発明における粘結剤成分の添加量である
が、共重合体の苛性アルカリ中和物は耐火物に対
して1.0〜7.0部、Ca(OH)2、CaOは0.3〜5.0部の
範囲が望ましい。ここに示した範囲外でも利用で
きないことはないが、添加量がこの範囲より少な
い場合、鋳型として適当な強度あるいは生産能率
が得られない。また添加量が多い場合、必要以上
の強度が付与され経済性の面でも好ましくない。 本発明による鋳型の製作方法によつて次の効果
が得られる。(1)鋳型砂の調製が容易。(2)粘結材料
が身体、衣服に付着しても水洗で容易に除去でき
る。(3)鋳型砂の可使用時間が長い。(4)鋳型強度が
大である。(5)鋳型成型時の作業環境が良好であ
る。(6)鋳型の生産効率が良い。(7)CO2ガスの使用
量が少なくても目的とする鋳型強度が得られる。
(8)CO2ガス吹き込み後の鋳型は自硬硬化性があ
る。 次に実施例により本発明をさらに具体的に説明
するが、これらに限定されるものではない。 実施例 スチレン−無水マイレン酸共重合体120grと苛
性ソーダ50gr、水180grを混合後加熱溶解させ
た。この溶液に消石灰300gr、水500grを順次添加
したのち撹拌により白色のサスペンシヨン溶液を
つくつた(粘結剤1とする)。 メチルビニルエーテル−無水マイレン酸共重合
体120grと苛性ソーダ50gr、水180grを混合後加熱
溶解させた。この溶液に消石灰300gr、水500grを
順次添加したのち撹拌により白色のサスペンシヨ
ン溶液をつくつた(粘結剤2)。 これらの粘結剤をJIS100号けい砂1Kgに対し
40gr添加混合した後、直径50mmφ、長さ50mmの試
験片につき固め、CO2ガスを1Kg/cm2の圧力で
5sec通気し、試験片製作直後とそれから24時間経
過後の圧縮強度を調べた。また比較例として、ア
クリル酸エステルとアクリル酸アンモンとの共重
合体をJIS100号けい砂1Kgに対し30gr添加し、更
に水20grおよび消石灰20grを添加し混合した後上
記と同様にして試験片につき固め同様の試験を行
つた。結果を表に示す。
The present invention relates to a method of manufacturing a mold for casting. Molds for metal casting that have been in practical use include those that use inorganic binders such as sodium silicate, and those that use organic binders such as phenolic resins and furan resins. All of these molds have the property of being able to withstand the pressure and heat during casting of molten metal. However, in the former case, the disintegration of the mold after casting is poor, making it extremely difficult to remove the casting and increasing the man-hours required to manufacture the casting.
Molds using organic binders do not have these problems. The mold hardening method involves curing by a chemical reaction of the binder component added to the molding sand, and after filling the molding sand with the binder added into the membrane mold, CO 2 gas or amine gas is injected into the mold. There are also those that harden the mold by blowing into it. In the former mold hardening method, a chemical reaction is started at the same time as the binding agent is added to the molding sand, so there is a limit to the time period during which the molding sand can be used effectively, so-called pot life. The latter method includes, for example, the so-called CO 2 process, in which molding sand with sodium silicate as a binder is blown with CO 2 gas to harden it, or a mold with a hydroxyl group-containing resin (e.g., phenolic resin) and polyisocyanate as a binder. There are methods that harden sand by blowing amine gas into it, and methods that use CO 2 gas to harden a combination of acrylic copolymer or phenol resin and calcium hydroxide. These hardening methods can extend the pot life of the molding sand compared to the chemical reaction of the binder component in the molding sand mentioned above, and also improve mold production efficiency because the mold hardens immediately when gas is blown into it. can be increased. However, since the CO 2 process uses sodium silicate as a binder, there are problems with mold disintegration, and those that use amine gas have problems with the toxicity and odor of the amine gas. In addition, when a copolymer of acrylic ester, ammonium acrylate, or sodium acrylate is combined with calcium hydroxide and cured with CO 2 gas, (1) ammonia gas is released during molding sand preparation or molding. There are problems such as deterioration of the working environment and (2) lack of strength immediately after CO 2 gas injection. Furthermore, those using phenolic resin do not contaminate the working environment due to the generation of ammonia gas, etc., but since the mold hardens only by drying after CO 2 gas is blown into the mold, there is little increase in the strength of the mold. Furthermore, the inventors have previously developed a mold made of a combination of polyvinyl alcohol and calcium hydroxide or calcium oxide and CO 2 gas as a technology to improve the problems of the conventional CO 2 process or other molds described above. A production method was proposed. Although this method has the feature of greatly improving the conventional technology, when manufacturing a large mold, it is difficult to uniformly harden the inside of the mold. The present invention provides a mold manufacturing method that takes advantage of the advantages of the prior art described above and improves the problems. Specifically, the present invention provides a mold manufacturing method that (1) has good mold disintegrability, (2) does not contain toxic or malodorous substances, and (3) has good production efficiency. The method for manufacturing a mold provided by the present invention combines the advantages of the CO 2 process and the advantages of a mold using an organic binder. The components constituting the material of the present invention will be explained in detail below. The polymers used in the present invention are styrene-maleic anhydride copolymer and methyl vinyl ether-maleic anhydride copolymer. When these polymers are dissolved in water, they require caustic alkali, whereby the carboxyl groups of the polymers and alkali metals such as Na and K form neutralizing bonds and are dissolved in water. Instead of caustic alkali, Mg(OH) 2 , ammonia, amine, etc. can be dissolved in water, but they harden at room temperature without spraying CO 2 gas, and ammonia gas is generated, making the work environment worse. Therefore, it is inappropriate. In the present invention, Ca(OH) 2 or CaO can be used alone, but they may be used simultaneously. These Ca(OH) 2 or CaO are for polymers
It is preferable to use it at 800% or less, preferably 300% or less. When used as a component of a mold binder, they may be suspended in an aqueous solution of the polymer in advance, or they may be added alone to the refractory particles. In addition, when using an aqueous polymer solution or an aqueous solution in which Ca(OH) 2 or CaO is suspended as a mold binder, wood flour or various emulsions, latexes, etc. can be added to make the solution sticky depending on the amount added. It can improve binding strength and adjust viscosity. The binder thus produced is packaged in the following two forms (A) and (B). (A) First component: Caustic alkali neutralized aqueous solution of polymer, Second component: Ca(OH) 2 or CaO. (B) First component: A suspension of Ca(OH) 2 or CaO in a caustic alkali neutralized aqueous solution of a polymer. The binder packaged and provided in this way is of type (A) in which two components are added and mixed into refractory particles, and in type (B), the first and second components are mixed together.
Only the ingredients are added and mixed to obtain molding sand. After this molding sand is filled into a model, when CO 2 gas is blown into the mold, the mold immediately hardens and can be used as a casting mold. If the molding sand is kept tightly sealed without blowing CO 2 gas into it, the molding sand will not harden and can be stored for a long time. The amount of the binder component added in the present invention is desirably 1.0 to 7.0 parts for the caustic alkali neutralized copolymer and 0.3 to 5.0 parts for Ca(OH) 2 and CaO based on the refractory material. . Although it is not impossible to use it outside the range shown here, if the amount added is less than this range, it will not be possible to obtain adequate strength or production efficiency as a mold. Moreover, if the amount added is large, strength will be imparted more than necessary, which is also unfavorable from an economic point of view. The following effects can be obtained by the mold manufacturing method according to the present invention. (1) Easy preparation of molding sand. (2) Even if the caking material adheres to the body or clothes, it can be easily removed by washing with water. (3) The pot life of the molding sand is long. (4) The mold strength is high. (5) Good working environment during mold molding. (6) Good mold production efficiency. (7) The desired mold strength can be obtained even if the amount of CO 2 gas used is small.
(8) The mold after CO 2 gas injection has self-hardening properties. Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto. Example 120g of styrene-maleic anhydride copolymer, 50g of caustic soda, and 180g of water were mixed and then heated to dissolve. To this solution, 300g of slaked lime and 500g of water were sequentially added and stirred to prepare a white suspension solution (referred to as binder 1). 120g of methyl vinyl ether-maleic anhydride copolymer, 50g of caustic soda, and 180g of water were mixed and then heated to dissolve. To this solution, 300g of slaked lime and 500g of water were sequentially added and stirred to prepare a white suspension solution (binder 2). Add these binders to 1 kg of JIS No. 100 silica sand.
After adding 40gr and mixing, solidify the test piece with a diameter of 50mmφ and a length of 50mm, and CO 2 gas was added at a pressure of 1Kg/cm 2.
Aeration was performed for 5 seconds, and the compressive strength was examined immediately after making the test piece and 24 hours later. As a comparative example, 30 gr of a copolymer of acrylic ester and ammonium acrylate was added to 1 kg of JIS No. 100 silica sand, and 20 gr of water and 20 gr of slaked lime were added and mixed, and then hardened into a test piece in the same manner as above. A similar test was conducted. The results are shown in the table.

【表】 本発明のもの、すなわち粘結剤1と2は造型直
後および24時間経過後の圧縮強度が比較例にくら
べて著しく高い。作業環境も良好である。一方、
比較例は鋳型砂調製時あるいは造型時にアンモニ
ア臭が発生し、作業環境の点で問題がある。また
鋳型の強度も比較的低い。 本発明はCO2ガスとの反応性が良好で、硬化が
速く鋳型の生産能率が良い。しかも少ないCO2
ス量で鋳型を硬化できるため経済的でもある。
[Table] The compressive strength of the products of the present invention, that is, binders 1 and 2, immediately after molding and after 24 hours was significantly higher than that of the comparative example. The working environment is also good. on the other hand,
In the comparative example, an ammonia odor was generated during the preparation of molding sand or during molding, which caused problems in terms of the working environment. The strength of the mold is also relatively low. The present invention has good reactivity with CO 2 gas, hardens quickly, and has good mold production efficiency. Moreover, it is also economical because the mold can be hardened with a small amount of CO 2 gas.

Claims (1)

【特許請求の範囲】[Claims] 1 スチレン−無水マレイン酸共重合体、メチル
ビニルエーテル−無水マレイン酸共重合体の少な
くとも1種よりなる苛性アルカリ中和物の水溶液
に、Ca(OH)2およびCaOの少なくとも1つを添
加したものからなる粘結材料を、耐火物粒子に添
加混合した後、CO2ガスを吹付けて硬化させるこ
とを特徴とする鋳型の製作方法。
1. From an aqueous solution of a caustic alkali neutralized product consisting of at least one of styrene-maleic anhydride copolymer and methyl vinyl ether-maleic anhydride copolymer, to which at least one of Ca(OH) 2 and CaO is added. A mold manufacturing method characterized by adding and mixing a caking material to refractory particles and then curing the mixture by spraying CO 2 gas.
JP3759677A 1977-04-04 1977-04-04 Preparation of mold Granted JPS53127324A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP3759677A JPS53127324A (en) 1977-04-04 1977-04-04 Preparation of mold

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP3759677A JPS53127324A (en) 1977-04-04 1977-04-04 Preparation of mold

Publications (2)

Publication Number Publication Date
JPS53127324A JPS53127324A (en) 1978-11-07
JPS6123057B2 true JPS6123057B2 (en) 1986-06-04

Family

ID=12501929

Family Applications (1)

Application Number Title Priority Date Filing Date
JP3759677A Granted JPS53127324A (en) 1977-04-04 1977-04-04 Preparation of mold

Country Status (1)

Country Link
JP (1) JPS53127324A (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5362729A (en) * 1976-11-16 1978-06-05 Kuraray Co Preparation of foundry sand mold

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5362729A (en) * 1976-11-16 1978-06-05 Kuraray Co Preparation of foundry sand mold

Also Published As

Publication number Publication date
JPS53127324A (en) 1978-11-07

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