JPS60158944A - Composition for curable casting mold - Google Patents

Abstract

PURPOSE:To provide a compsn. for a process producing a cold box mold for casting in which peroxide is used as an oxidizing agent and an acid curable resin is cured by sulfur dioxide by consisting compsn. of the acid curable resin and 1 or >=2 kinds among prescribed org. compds. or natural fats and oils. CONSTITUTION:A compsn. for a process for producing a casting mold in which an acid curable resin is cured by sulfur dioxide with peroxide as oxidizing agent is formed by consisting said compsn. of the acid curable resin and 1 or 2>= kinds among the following compdsn. or the mixture composed thereof and such compsn. is used in producing the cold box mold for casting. The above-mentioned compsn. are org. compound such as prescribed ether, ketone, aldehyde, aliphat. or arom. hydrocarbon and natural animal and vegetable fats and oils. The casting mold having high initial strength is thus obtd. and the productivity of the casting mold is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to curable molding compositions. In particular, it is used in a method of manufacturing molds by injecting gaseous or aerosol sulfur dioxide into a sand mold made by adding acid-curing resin as an essential component to fire-resistant granular material and then kneading it with peroxide. , relating to curable molding compositions.

Conventionally, in order to manufacture molds in medium to large quantities, a shell molding method has been used in which a refractory granular material is coated with a phenolic resin, and the coated material is filled into a mold using air pressure or the like and thermoset molded.

However, in order to save energy during mold manufacturing, mold production speed, and improve the quality of molds and castings, the cold hox mold manufacturing method, in which gaseous or aerosol substances are used to harden at room temperature, has been adopted as a mold manufacturing method that replaces the shell molding method. Serious attempts are being made to introduce it in the foundry industry.

The cold box method involves curing acid-curing resins, typically furan-based resins, with sulfur dioxide using peroxide as an oxidizing agent, and curing polyols and polyisocyanates with an aerosol-like tertiary amine as a catalyst.
There is a urethane cold box that hardens at -.

The mold using the urethane cold box is
There are disadvantages 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.

On the other hand, the Francold box has been rapidly attracting attention in recent years as a method for solving the above-mentioned difficulties.

The present invention relates to a curable mold composition suitable for use in the Fran cold box method, and is used to improve curing behavior such as initial strength of a cold box that instantly hardens by injecting gas at room temperature. The present invention relates to a curable molding composition mainly comprising an acid-curable resin.

Conventionally, automatic molding machines have been used to manufacture molds in medium to large quantities.Acid-curing resin and peroxide are added to fire-resistant granular material and kneaded to coat the surface of the fire-resistant granular material, and then automatically molded using air pressure, etc. Generally, filling, molding, curing, and removal are performed continuously in a cycle of less than one minute. Therefore, in the cold box method, in order to further improve mold productivity, it is desired to improve the initial strength so that the mold can be sufficiently mechanically handled within one minute after molding.

As a result of intensive research, the present inventors have discovered that a specific compound or We have found a composition for manufacturing cold box molds that uses the mixture in combination.

That is, the present invention is a cold-curing method in which an acid-curing resin comprising an acid-curing resin and one or more of the following compounds or mixtures a) to t) is cured with sulfur dioxide using peroxide as an oxidizing agent. Composition for box mold manufacturing method a) General formula R1-0-R2, R1-0-R2 or R1
-0HO compound (R1 and R2 are saturated or unsaturated aliphatic hydrocarbon groups having 1 to B carbon atoms) C) The substituent attached to the beni/cene ring is a methoxy group, an aldehyde group, or a nitro group, respectively. Aromatic compounds having one or more or two or more types, or two or more types including hydroxyl groups, or two or more hydroxyl groups d) Aliphatic hydrocarbons/elements having 5 to 12 carbon atoms e) Heterocyclic compounds having one or more oxygen atoms in the five- or six-membered ring or compounds having one or more aldehyde groups in the furan ring f) Compounds represented by the general formula R, -000-R2 (R1
and R2 is an aliphatic hydrocarbon group having 18 or less carbon atoms, provided that one of them may be hydrogen), and R2 is an unsaturated aliphatic hydrocarbon group having 8 or less carbon atoms. ) 1) Compounds represented by the general formula R1-000-R, -000-R, (RR and R3 are fatty acids having 6 or less carbon atoms 1)
2 flaming hydrogen group) jl Compound represented by the general formula R1-Coo-R2-0-R, (R,, R2 and R1 are aliphatic having 4 or less carbon atoms (R1, R2 and R1 are the number of carbon atoms 6 or less aliphatic hydrocarbon or aromatic hydrocarbon group) t) Natural animal and vegetable oils and fats or natural resins.

In the present invention, the above a) to t] used in combination with acid-curing resin
Specific examples of the compound or mixture include the following.

Dipropyl ether, methyl ethyl ketone, propionaldehyde, heptyl aldehyde, dibentyl ether, cybentylacetone, allyl acetone, inbutyl vinyl ether, toluene, xylene, amylbenzene, dodecylbenzene, benzaldehyde, anisole,
Nitrobenzene, dinitrobenzene, -! 1-IJ tyraldehyde, anisaldehyde, resorcinol, phloroglucinol, imprene, heptane, octane, furan, dioxane, furfural, ethyl acetate, acetic acid-
Hexyl, methyl oleate, methyl benzoate, hexyl benzoate, butyl acrylate, vinyl acrylate, butyl methacrylate, allyl methacrylate, diallyl phthalate, divinyl phthalate, ethylene glycol diacetate, propylene glycol diacetate, acetic acid Ethyl cellosolve, butyl cellosolve acetate, tributyl phosphite, triphenyl phosphite, castor oil, linseed oil, crude tall oil, wood rosin, etc., and one or more of these are used in 100 parts by weight of the acid-curing resin. 5 to 50
The heavy weight part is used in combination with 10 to 40 parts by weight. As a result, the initial strength development, which is an important curing behavior for molds, is 15 to 2 times higher than when using only conventional acid-curing resins.
It has been improved by 00%.

The reason for this is that the above-mentioned specific compound or mixture using a combination of peroxide and sulfur dioxide promotes the chemical reaction, and also induces surface hydrogen bonding between the refractory granular material and the acid-curing resin. Chemically improved surface properties such as improved interfacial adhesion, improved permeability and diffusivity to the composition interface of the cured mold, i.e., solid, liquid, and liquid-liquid interfaces, and cohesive force for refractory particles. This is thought to be due to the physical improvement and modification of the properties such as these.

For forms in which the acid-curing resin and the above-mentioned specific compounds or mixtures are used together, they may be stirred and mixed into the acid-curable resin [7], or they may be added to the reaction system from the beginning during the production of the acid-curable resin. You can leave it there.

In the composition of the present invention, the acid-curable resin used is one or more of furan, urea, phenol and melamine, a polycondensed metal with formalin, or a mixture of two or more of these.

Further, as peroxides, ketone-based, aromatic-based organic peroxides, and inorganic peroxides such as hydrogen peroxide are used, but the present invention is not limited to these.

Further, as the refractory granular material, in addition to crushed sand mainly composed of quartz, zircon, chromite, oripin sand, etc. are used.

Examples are given below to explain the present invention in more detail.
The advantages of the present invention will be described, but the scope of the present invention will not be limited by the following examples.
After adding 9 parts by weight of the compound or mixture listed in Table 1 and mixing for 1 minute in a kitchen mixer, 12 parts by weight of methyl ethyl ketone peroxide with an active oxygen concentration of 10 was added and mixed, and a mold for bending strength test was prepared. Frame (25X25X2
50), sulfur dioxide gas was blown from the top of the mold to form the mold [7].

The initial strength of the formed mold was measured using a bending strength tester 30 seconds after the start of sulfur dioxide gas injection.
The mold bending strength (blank) in the case of furanurea-formalin resin not used together with ~t) was expressed as a ratio of 100. These results are shown in Table 1.

As shown in Table 1, compared to the blank, the initial bending strength increased in all the examples, and the increase rate was at least 115.
The maximum value was 200 or more, indicating a sufficient effect on the development of initial bending strength.

Claims (1)

[Claims] 1. An acid-curable resin consisting of an acid-curable resin and one or more of the following compounds or mixtures a) to t) is treated with sulfur dioxide using peroxide as an oxidizing agent. Compounds (R1 and R
2 is a saturated or unsaturated aliphatic hydrocarbon group having 1 to 8 carbon atoms or hydrogen) The substituent attached to the C1 benzene ring is a methoxy group. Aromatic compound dl having one or more aldehyde groups or nitro groups, or two or more types including hydroxyl groups, or two or more hydroxyl groups dl The number of carbon atoms is 5 to 12 Aliphatic hydrocarbons e) Heterocyclic compounds having one or more oxygen atoms in the five- or six-membered ring or compounds having one or more aldehyde groups in the furan ring fl Compounds represented by the general formula R1-000-R2 (R
1 and R2 have 18 or less carbon atoms, and fats have 8 carbon atoms.
The following aliphatic hydrocarbons) and R2 are unsaturated aliphatic hydrocarbon groups having 8 or less carbon atoms) 1) General formula R1-C! Compounds represented by 00-R,, -000-R, (R,,, R2 and R3 have 6 carbon atoms)
The following aliphatic hydrocarbon groups) j) Compounds represented by the general formula R1-Coo-R,, -0-R, (R1, R2 and R3 are aliphatic hydrocarbon groups having 4 or less carbon atoms) (R1, R2 and B are aliphatic hydrocarbon or aromatic hydrocarbon groups having 6 or less carbon atoms) t) Natural animal and vegetable oil or fat or natural resin 2) The amount of the compound or mixture of al to t) is 100 parts by weight of the acid-curing resin. The composition according to claim 1, wherein the amount is 5 to 50 parts by weight.