JPH0510177B2

JPH0510177B2 -

Info

Publication number: JPH0510177B2
Application number: JP59013019A
Authority: JP
Inventors: Yasuyuki Kawakatsu; Yoshihiro Ejiri; Kazuo Ito
Original assignee: Kao Quaker Co Ltd
Current assignee: Kao Quaker Co Ltd
Priority date: 1984-01-27
Filing date: 1984-01-27
Publication date: 1993-02-09
Also published as: JPS60158943A

Description

[Detailed description of the invention]

本発明は鋳型の製造方法に関する。更に詳しく
は、耐火性粒状材料に酸硬化性樹脂と過酸化物と
エーテル類、ケトン類、アルデヒド類、脂肪族炭
化水素、芳香族炭化水素等の化合物、又は天然動
植物油脂等の混合物を添加混練成型した砂型に、
ガス状又はエロゾル状の二酸化硫黄を吹き込ん
で、初期の鋳型強度を増進させ且つ生産速度を改
良する鋳型の製造方法に関するものである。従来、鋳物工場で中子及び主型を製造するに当
り、産業廃棄物公害の低減、生産性の合理化、迅
速性等、種々の利点により有機自硬性粘結剤を使
用する鋳型製造法が、水ガラス、セメント等無機
系粘結剤を使用する製造法に替わり広く使用され
る様になつた。しかし有機自硬性粘結剤を使用する従来の鋳型
製造法もいくつかの難点が存在し、例えば粒状耐
火物と混練された有機自硬性粘結剤は、自硬性故
に、模型に充填されて目的とする鋳型を造型する
際に通常数十分から数時間の硬化強度発現の為の
放置時間が必要であり、一方混練開始から自硬成
分の化学反応が始まる為、粒状耐火物粒子間に粘
結力が失われ、作業に伴なう可使時間が限定され
るという問題点がある。従つて鋳型製造に長時間を要し、かつ混練砂の
可使時間に制限がある有機自硬性鋳型法は中・大
量の鋳型生産を必要とする分野には適当でない。通常、これらの用途には従来よりフエノール樹
脂を耐火性骨材に被覆したものを熱硬化させるク
ローニング法や、フラン系樹脂を使用するホツト
ボツクス法があるが、近年省エネルギー、更に生
産性を向上させるため、コールドボツクス法と呼
ばれる所の、砂型にガス状又はエロゾル状物質を
吹き込んで、瞬時に鋳型を製造する方法がこれら
の分野で実用化されつつある。コールドボツクス法の一つに有機ポリイソシア
ネートとポリオール型樹脂を鋳型用粘結剤として
用い、エロゾル状の３級アミンを注入して鋳型を
硬化させるウレタン系コールドボツクス法があ
る。併しながらこの方法は鋳物製造時の鋳砂の崩
壊性が悪いとか、砂かみ、すくわれ、ピンホー
ル、すす欠陥等の鋳造欠陥が発生しやすい等の欠
点が存在している。それに替えてフラン系、フエノール系、尿素系
樹脂の如き酸硬化性樹脂を酸化剤存在下にガス状
あるいはエロゾル状の二酸化硫黄を吹き込んで硬
化させる「酸硬化性コールドボツクス法」（特許
第807786号）が前記ウレタン系コールドボツクス
法の難点を解決する方法として近年急速に注目を
集めている。本発明はこの酸硬化性コールドボツクス法の改
良に関するものである。即ち中大量に連続造型さ
れる鋳型生産分野で、コールドボツクス法を利用
して製造する場合は、混練された耐火性粒状物を
型枠に充填後、数分間望ましくは１分以内で機械
的手段を用いて型枠から取り出される必要があつ
た。従来の酸硬化性樹脂と過酸化物だけで造型さ
れた鋳型は、30秒での初期強度が十分でなく、部
分的に破損を起したり、鋳型の充填不良等がみら
れた。本発明者らは、鋭意研究の結果、鋳型生産性を
更に向上させるため、成型後１分以内の初期強度
を改善する製造法として、耐火性粒状材料中に、
エーテル類、ケトン類、アルデヒド類、脂肪族炭
化水素、芳香族炭化水素等の１種又は２種以上の
化合物、又は天然動植物油脂等の１種以上の混合
物を添加し、撹伴混練した後、酸硬化性樹脂及び
過酸化物を添加混練するか、又は耐火性粒状材料
に、酸硬化性樹脂を添加混練後、エーテル類、ケ
トン類、アルデヒド類、脂肪族炭化水素、芳香族
炭化水素等の１種又は２種以上の化合物、又は天
然動植物油脂等の１種又は２種以上の混合物を添
加し、更に過酸化物を添加混練し、ガス状又はエ
ロゾル状の二酸化硫黄を吹き込んで鋳型を製造す
る方法を見出した。フルフリルアルコール、尿素、フエノール及び
メラミンの１種又は２種以上のホルマリンとの重
縮合物又はこれらの２種以上の混合物からなる酸
硬化性樹脂と、過酸化物と、耐火性粒状材料に対
して0.05〜2.0重量％の下記のａ）〜ｌ）の化合
物又は混合物の１種又は２種以上とを予め混合す
ること無しに使用時に添加混練し成型して得られ
た砂型に対して、ガス状又はエロゾル状の二酸化
硫黄を吹き込むことを特徴とする鋳型の製造方法
に関わるものである。ａ一般式R₁−Ｏ−R₂， The present invention relates to a method for manufacturing a mold. More specifically, a mixture of acid-curable resin, peroxide, ethers, ketones, aldehydes, aliphatic hydrocarbons, aromatic hydrocarbons, etc., or natural animal and vegetable oils and fats is added and kneaded to the fire-resistant granular material. In the molded sand mold,
The present invention relates to a mold manufacturing method in which gaseous or aerosol sulfur dioxide is injected to enhance initial mold strength and improve production rate. Conventionally, when manufacturing cores and main molds at foundries, mold manufacturing methods using organic self-hardening binders have been used due to various advantages such as reduction of industrial waste pollution, rationalization of productivity, and speed. It has become widely used as an alternative to manufacturing methods that use inorganic binders such as water glass and cement. However, the conventional mold manufacturing method using organic self-hardening binders also has some drawbacks. For example, organic self-hardening binders kneaded with granular refractories are self-hardening, so they cannot be filled into molds for the purpose. When molding a mold, it is usually necessary to leave it for several tens of minutes to several hours to develop hardening strength.On the other hand, since the chemical reaction of the self-hardening components begins from the start of kneading, viscosity builds up between the granular refractory particles. There is a problem that cohesion is lost and pot life is limited due to work. Therefore, the organic self-hardening mold method, which requires a long time to manufacture molds and has a limited usable life of kneaded sand, is not suitable for fields requiring medium to large quantities of mold production. Normally, these applications include the cloning method, in which phenolic resin is coated on fire-resistant aggregate and then heat-cured, and the hot-boxing method, in which furan-based resin is used. A method called the cold box method, in which a mold is instantaneously produced by blowing a gaseous or aerosol substance into a sand mold, is being put into practical use in these fields. One of the cold box methods is a urethane cold box method in which an organic polyisocyanate and a polyol type resin are used as a mold binder, and an aerosol-like tertiary amine is injected to harden the mold. However, this method has drawbacks such as poor disintegration of casting sand during casting production, and the tendency to cause casting defects such as sand trapping, scooping, pinholes, and soot defects. Instead, the ``acid-curing cold box method'' (Patent No. 807786) involves blowing gaseous or aerosol sulfur dioxide into acid-curing resins such as furan-based, phenol-based, or urea-based resins in the presence of an oxidizing agent. ) has been rapidly attracting attention in recent years as a method for solving the difficulties of the urethane-based cold box method. The present invention relates to improvements in this acid-curing cold box method. In other words, in the field of mold production where medium to large quantities are continuously manufactured, when manufacturing using the cold box method, mechanical means can be used within several minutes, preferably within one minute, after filling the mold with kneaded refractory granules. It was necessary to remove it from the formwork using a . Conventional molds made using only acid-curing resin and peroxide did not have sufficient initial strength after 30 seconds, resulting in partial breakage and mold filling failures. As a result of intensive research, the present inventors have developed a manufacturing method that improves the initial strength within 1 minute after molding, in order to further improve mold productivity.
After adding one or more compounds such as ethers, ketones, aldehydes, aliphatic hydrocarbons, aromatic hydrocarbons, or a mixture of one or more natural animal and vegetable oils and fats, stirring and kneading, After adding and kneading acid-curable resin and peroxide, or adding and kneading acid-curable resin to fire-resistant granular material, ethers, ketones, aldehydes, aliphatic hydrocarbons, aromatic hydrocarbons, etc. A mold is produced by adding one or more compounds or a mixture of one or more natural animal and vegetable oils, etc., adding peroxide and kneading, and blowing gaseous or aerosol sulfur dioxide. I found a way to do it. For acid-curing resins consisting of polycondensates of furfuryl alcohol, urea, phenol, and melamine with one or more formalin, or a mixture of two or more of these, peroxides, and fire-resistant granular materials. A gas The present invention relates to a mold manufacturing method characterized by blowing sulfur dioxide in the form of sulfur dioxide or aerosol. a General formula R ₁ -O-R ₂ ,

【式】又はR₁− CHOで示される化合物（R₁及びR₂は炭素原子
数２〜８の飽和又は不飽和脂肪族炭化水素基）ｂ一般式[Formula] or a compound represented by R ₁ - CHO (R ₁ and R ₂ are saturated or unsaturated aliphatic hydrocarbon groups having 2 to 8 carbon atoms) b General formula

【式】で示される化合物（R₁ 及びR₂は炭素原子数18以下の脂肪族炭化水素
基又は水素）ｃベンゼン環に付く置換基が、メトキシ基、ア
ルデヒド基又はニトロ基の夫々１個又は２個以
上又は２種以上、又はヒドロキシル基を含めた
２種以上である芳香族化合物ｄ炭素原子数が５〜12である脂肪族炭化水素ｅ五員環又は六員環中に酸素原子を１以上持つ
複素環式化合物又はフラン環にアルデヒド基を
１以上持つ化合物ｆ一般式R₁−COO−R₂で示される化合物（R₁
及びR₂は炭素原子数18以下の脂肪族炭化水素
基、但し一方は水素であり得る）ｇ一般式Compound represented by [Formula] (R ₁ and R ₂ are aliphatic hydrocarbon groups having 18 or less carbon atoms or hydrogen) c The substituent attached to the benzene ring is one each of a methoxy group, an aldehyde group, or a nitro group, or Aromatic compounds containing 2 or more or 2 or more types, or 2 or more types including hydroxyl groups d Aliphatic hydrocarbons having 5 to 12 carbon atoms e 1 oxygen atom in a 5- or 6-membered ring Heterocyclic compounds having one or more aldehyde groups on the furan ring f Compounds represented by the general formula R ₁ -COO-R ₂ (R ₁
and R ₂ is an aliphatic hydrocarbon group having up to 18 carbon atoms, but one may be hydrogen) g General formula

【式】で示される化合物（R₁は炭素原子数８以下の脂肪族炭化水素基）ｈ一般式Compound represented by [Formula] (R ₁ is an aliphatic hydrocarbon group having 8 or less carbon atoms) h General formula

【式】で示される化合物（R₁及びR₂は炭素原子数８以下の不飽和脂肪族
炭化水素基）ｉ一搬式R₁−COO−R₂−OOC−R₃で示される
化合物（R₁，R₂及びR₃は炭素原子数６以下の
脂肪族炭化水素基）ｊ一般式R₁−COO−R₂−Ｏ−R₃で示される化
合物（R₁，R₂及びR₃は炭素原子数４以下の脂
肪族炭化水素基）ｋ一般式Compounds represented by the formula (R ₁ and R ₂ are unsaturated aliphatic hydrocarbon groups having 8 or less carbon atoms) i Compounds represented by the formula R ₁ -COO-R ₂ -OOC-R ₃ (R ₁ , R ₂ and R ₃ are aliphatic hydrocarbon groups having 6 or less carbon atoms) j Compounds represented by the general formula R ₁ -COO-R ₂ -O-R ₃ (R ₁ , R ₂ and R ₃ are carbon atoms aliphatic hydrocarbon group of number 4 or less) k General formula

【式】で示される化合物（R₁， R₂及びR₃は炭素原子数６以下の脂肪族炭化水
素又は芳香族炭化水素基）ｌ天然動植物油脂又は天然樹脂本発明に於て耐火性粒状材料又は酸硬化性樹脂
で被覆された耐火性粒状材料中に添加混練される
上記ａ）〜ｌ）の化合物又は混合物としては具体
的には次の様なものがあげられる。スチレン、ジ
ビニルベンゼン、トルエン、キシレン、ジブチル
ケトン、メチルエチルケトン、亜リン酸トリ−ｎ
−ブチル、アクリル酸−ｎ−ブチル、メタクリル
酸−ｎ−ブチル、メタクリル酸アリル、トリメチ
ロールプロパントリアクリレート、ジプロピルエ
ーテル、イソブチルビニルエーテル、アニソー
ル、アリルエーテル、フラン、酢酸ブチルセロソ
ルブ、アクリル酸ビニル、アリルアセトン、メシ
チルオキシド、カプロン、ｐ−アニスアルデヒ
ド、ベンズアルデヒド、フルフラール、１，４ジ
オキサン、蟻酸ｎ−ヘキシル、酢酸−ｎ−ブチ
ル、酢酸ベンジル、プロピオン酸−ｎ−ブチル、
ヤシ酸メチル、オレイン酸メチル、プロピレング
リコールジアセテート、ｎ−ヘキサン、イソプレ
ン、ｎ−ヘプタン、ヒマシ油、テレピン油、粗ト
ール油等であり、これらの１種又は２種以上が、
耐火性粒状材料に対して0.05重量％〜２重量％、
望ましくは0.1重量％〜１重量％使用される。更
にこれに過酸化物が添加混練された組成物は、上
記ａ）〜ｌ）の化合物又は混合物が添加混練され
ないものに比べて、型枠への充填性に富むと共
に、硬化した鋳型の初期強度が一段と向上する。
その理由は詳細が判明している訳ではないが、恐
らく組成物界面、すなわち固体−液体、液体−液
体界面に働きかけて、粒子に対する濡れ浸透及び
拡散を容易にすると共に物理的分散性が付与され
るものと推察される。同時に二酸化硫黄ガスと過
酸化物との化学反応を促進させる作用を併せ持つ
ていると推察される。上記ａ）〜ｌ）の化合物又
は混合物の使用量が耐火性粒状材料に対して0.05
重量％未満では粒子に対する濡れ浸透及び拡散性
向上の効果がなく、又耐火性粒状材料に対して
2.0重量％を越えると酸硬化性樹脂に対する希釈
効果が大きくなり過ぎ、強度低下を起こす。本発明における酸硬化性樹脂ａ）〜ｌ）の化合
物又は混合物との配合割合は、重量比で100：５
〜100：50が好ましい。化合物又は混合物の比率
が酸硬化性樹脂100重量部に対して５重量部未満
では粒子に対する濡れ浸透及び拡散性向上の効果
が少なく、又50重量部を越えると酸硬化性樹脂に
対する希釈効果が大きくなり過ぎ、強度低下を起
こす。本発明に用いられる、酸硬化性樹脂は、酸を硬
化触媒として、硬化し得る樹脂であれば全て使用
可能で、一般にはフラン、尿素、フエノール、メ
ラミンの１種又は２種以上のホルマリン重縮合物
又はこれ等重縮合物の２種以上の混合物である。
又耐火性粒状材料としては、硅質分の高い硅砂、
ジルコン、クロマイト、アルミナ、オリビン砂等
の鋳造用耐火物粒子であれば本質的に何れも使用
可能である。過酸化物としては、ケトン系、ジア
シル系、ジアルキル系等の有機過酸化物及び過酸
化水素等の無機系過酸化物の夫々単独もしくは２
種以が上用いられる。これら酸硬化性樹脂並びに
過酸化物の使用量は従来通常使用される量範囲で
あれば凡て使用可能である。通常、耐火性粒状材
料1000重量部に対して、酸硬化性樹脂５〜30重量
部、過酸化物３〜10重量部使用される。以下に、本発明をより詳細に説明するため実施
例をあげて説明するが、これにより本発明の範囲
を制限するものではない。実施例耐火性粒状材料であるフラタリー砂（オースト
ラリア産）2000ｇ中に第１表に示す化合物又は混
合物の１種以上を加えて１分間キツチンミキサー
で撹拌混練後、フラン尿素ホルマリン樹脂20ｇを
加えて１分間撹拌混練した。これに活性酸素が10
％であるメチルエチルケトンパーオキサイド８ｇ
を加えて、更に１分間撹拌混練した。混合終了した試料を鋳型用型枠（25×25×250）
にコアシユーター〔新東工業(株)製〕を用いて充填
後、二酸化硫黄ガスを注入し、鋳型を成型した。混練砂の充填性及び初期曲げ強度を評価するに
当り、成型後の鋳型重量と二酸化硫黄ガス吹き込
み開始から数えて30秒後の曲げ強度を測定した。第１表に示した値は、例示の化合物又は混合物
を加えなかつた場合の鋳型重量と初期曲げ強度
（ブランク）を100とした比率で示す。Compound represented by [Formula] (R ₁ , R ₂ and R ₃ are aliphatic hydrocarbon or aromatic hydrocarbon groups having 6 or less carbon atoms) l Natural animal or vegetable oil or natural resin Fire-resistant granular material in the present invention Or, specific examples of the compounds or mixtures of a) to l) above to be added and kneaded into the fire-resistant granular material coated with an acid-curable resin include the following. Styrene, divinylbenzene, toluene, xylene, dibutyl ketone, methyl ethyl ketone, tri-n phosphite
-Butyl, n-butyl acrylate, n-butyl methacrylate, allyl methacrylate, trimethylolpropane triacrylate, dipropyl ether, isobutyl vinyl ether, anisole, allyl ether, furan, butyl cellosolve acetate, vinyl acrylate, allyl acetone , mesityl oxide, caprone, p-anisaldehyde, benzaldehyde, furfural, 1,4 dioxane, n-hexyl formate, n-butyl acetate, benzyl acetate, n-butyl propionate,
Methyl coconut, methyl oleate, propylene glycol diacetate, n-hexane, isoprene, n-heptane, castor oil, turpentine oil, crude tall oil, etc., and one or more of these are
0.05% to 2% by weight of refractory granular material,
It is preferably used in an amount of 0.1% to 1% by weight. Furthermore, a composition in which peroxide is added and kneaded has better filling properties into a mold and has a lower initial strength of a hardened mold than a composition in which the above-mentioned compounds or mixtures a) to l) are not added and kneaded. will improve further.
The reason for this is not clear in detail, but it is probably because it acts on the composition interface, that is, the solid-liquid or liquid-liquid interface, making it easier to penetrate and diffuse the particles and imparting physical dispersibility. It is assumed that the At the same time, it is presumed to have the effect of promoting the chemical reaction between sulfur dioxide gas and peroxide. The amount of the compound or mixture of a) to l) above is 0.05% for the refractory granular material.
If it is less than % by weight, there is no effect of improving wetting and diffusion of particles, and
If it exceeds 2.0% by weight, the dilution effect on the acid-curing resin becomes too large, causing a decrease in strength. The compounding ratio of the acid-curing resins a) to l) with the compound or mixture in the present invention is 100:5 by weight.
~100:50 is preferred. If the ratio of the compound or mixture is less than 5 parts by weight to 100 parts by weight of the acid-curing resin, the effect of improving wetting and penetration of the particles and diffusivity will be small, and if it exceeds 50 parts by weight, the diluting effect on the acid-curing resin will be large. too much, resulting in a decrease in strength. The acid-curable resin used in the present invention can be any resin that can be cured using an acid as a curing catalyst, and is generally made by formalin polycondensation of one or more of furan, urea, phenol, and melamine. or a mixture of two or more of these polycondensates.
In addition, as fire-resistant granular materials, silica sand with high silica content,
Essentially any casting refractory particles such as zircon, chromite, alumina, olivine sand, etc. can be used. As peroxides, organic peroxides such as ketone type, diacyl type, dialkyl type, etc. and inorganic peroxides such as hydrogen peroxide can be used alone or in combination.
More than one species is used. The amounts of these acid-curable resins and peroxides used can be within the ranges conventionally used. Usually, 5 to 30 parts by weight of acid-curing resin and 3 to 10 parts by weight of peroxide are used per 1000 parts by weight of the refractory granular material. EXAMPLES Below, examples will be given to explain the present invention in more detail, but the scope of the present invention is not limited thereby. Example Add one or more of the compounds or mixtures shown in Table 1 to 2000 g of flattery sand (produced in Australia), which is a refractory granular material, stir and knead for 1 minute with a kitchen mixer, then add 20 g of furanurea-formalin resin. The mixture was stirred and kneaded for a minute. This has 10 active oxygen
% methyl ethyl ketone peroxide 8g
was added, and the mixture was further stirred and kneaded for 1 minute. Place the mixed sample into a molding frame (25 x 25 x 250)
was filled using a core shooter (manufactured by Shinto Kogyo Co., Ltd.), sulfur dioxide gas was injected, and a mold was formed. In evaluating the filling properties and initial bending strength of the kneaded sand, the weight of the mold after molding and the bending strength 30 seconds after the start of sulfur dioxide gas injection were measured. The values shown in Table 1 are expressed as a ratio of mold weight and initial bending strength (blank) without addition of the exemplified compound or mixture as 100.

【表】【table】

【表】第１表に示す様に、ブランクに比べて本発明の
実施例のものは、鋳型充填密度が向上する為、重
量比で５％〜26％上昇すると共に、初期強度にお
いても10％〜95％の上昇しており、本発明の製造
法の有用性が認められる。実施例30〜35、比較例１〜３耐火性粒状材料であるフラタリー砂2000ｇ中
に、第２表に示す化合物又は混合物の１種以上を
加えて１分間キツチンミキサーで撹拌混練後、第
２表記載の酸硬化性樹脂20ｇを加えて１分間撹拌
混練した。これに活性酸素が10％であるメチルエ
チルケトンパーオキサイド８ｇを加えて、更に１
分間撹拌混練した。この混練物を用いて実施例１〜29と同様に、曲
げ強度測定用鋳型を成型し、二酸化硫黄ガス吹き
込み開始から数えて30秒後の曲げ強度を測定し
た。結果を第２表に示した。[Table] As shown in Table 1, compared to the blank, the mold packing density of the examples of the present invention is improved, so the weight ratio increases by 5% to 26%, and the initial strength also increases by 10%. The increase was ~95%, which confirms the usefulness of the production method of the present invention. Examples 30 to 35, Comparative Examples 1 to 3 One or more of the compounds or mixtures shown in Table 2 were added to 2000 g of flattery sand, which is a refractory granular material, and after stirring and kneading with a kitchen mixer for 1 minute, the compounds shown in Table 2 were mixed. 20 g of the acid-curable resin described above was added and kneaded with stirring for 1 minute. Add 8g of methyl ethyl ketone peroxide containing 10% active oxygen to this, and add 1
The mixture was stirred and kneaded for a minute. Using this kneaded material, a mold for measuring bending strength was molded in the same manner as in Examples 1 to 29, and the bending strength was measured 30 seconds after the start of sulfur dioxide gas blowing. The results are shown in Table 2.

【表】【table】

【table】

Claims

[Claims] 1. A fire-resistant granular material containing furfuryl alcohol,
0.05 to 2.0 for an acid-curing resin consisting of a polycondensate of urea, phenol, and melamine with formalin or a mixture of two or more of these, peroxide, and fire-resistant granular material. A gaseous or aerosol-like compound is added to a sand mold obtained by kneading and molding one or more of the following compounds or mixtures of a) to l) in weight% at the time of use without pre-mixing. A method for manufacturing a mold, characterized by blowing sulfur dioxide into the mold. a Compound represented by the general formula R ₁ -O-R ₂ , [Formula] or R ₁ - CHO (R ₁ and R ₂ are saturated or unsaturated aliphatic hydrocarbon groups having 1 to 8 carbon atoms) b General formula Compound represented by [Formula] (R ₁ and R ₂ are aliphatic hydrocarbon groups having 18 or less carbon atoms or hydrogen) c The substituent attached to the benzene ring is one each of a methoxy group, an aldehyde group, or a nitro group, or Aromatic compounds containing 2 or more or 2 or more types, or 2 or more types including hydroxyl groups d Aliphatic hydrocarbons having 5 to 12 carbon atoms e 1 oxygen atom in a 5- or 6-membered ring Heterocyclic compounds having one or more aldehyde groups on the furan ring f Compounds represented by the general formula R ₁ -COO-R ₂ (R ₁
and R ₂ is an aliphatic hydrocarbon group having 18 or less carbon atoms, however, one may be hydrogen) g Compound represented by the general formula [Formula] (R ₁ is an aliphatic hydrocarbon group having 8 or less carbon atoms) h Compound represented by the general formula [Formula] (R ₁ and R ₂ are unsaturated aliphatic hydrocarbon groups having 8 or less carbon atoms) i Compound represented by the transport formula R ₁ -COO-R ₂ -OOC-R ₃ (R ₁ , R ₂ and R ₃ are aliphatic hydrocarbon groups having 6 or less carbon atoms) j Compounds represented by the general formula R ₁ -COO-R ₂ -O-R ₃ (R ₁ , R ₂ and R ₃ is an aliphatic hydrocarbon group having 4 or less carbon atoms) k A compound represented by the general formula [formula] (R ₁ , R ₂ and R ₃ are aliphatic hydrocarbon or aromatic hydrocarbon groups having 6 or less carbon atoms) l Natural animal and vegetable oil or fat or natural resin 2 First, one or more of the compounds or mixtures of a) to l) are added to the fire-resistant granular material, stirred and kneaded, and then acid-curable resin and peroxide are added and kneaded. The method for manufacturing a mold according to claim 1, wherein gaseous or aerosol sulfur dioxide is blown into the mold. 3. After adding and kneading the acid-curable resin to the fire-resistant granular material, adding one or more of the compounds or mixtures of a) to l), and further adding and kneading a peroxide,
The method for manufacturing a mold according to claim 1, wherein gaseous or aerosol sulfur dioxide is blown into the mold.