JPS60154845A - Production of curable casting mold - Google Patents

Abstract

PURPOSE:To extend the pot life of a casting mold by adding at least one kind of stabilizer such as beta-diketone homolog at specific wt% to a refractory granular aggregate then adding and kneading an acid curing resin and peroxide to and with the mixture composed thereof. CONSTITUTION:At least one kind of stabilizer such as beta-diketone homolog, oxine homolog, oxime homolog or the like is added at 0.05-0.5% to a refractory granular aggregate having a pH value larger than 6, then an acid curing resin such as furan resin and peroxide consisting essentially of hydrogen proxide are added and mixed to and with the mixture composed thereof. Such mixture is permitted to stand and is packed into a molding flask. Sulfur dioxide and compressed air are further passed therethrough respectively in short time and a casting mold is formed. Since the metal, metallic oxide, etc. contained in the refractory aggregate are treated by the stabilizer in the above-mentioned method, the decomposition and deactivation of the peroxide are suppressed. The pot life is therefore extended and the waste of the kneaded material is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves molding a mixture obtained by adding and kneading an acid-curing resin and a peroxide composition to fire-resistant granular aggregate, and then injecting gaseous or aerosol sulfur dioxide into the mold. It relates to a manufacturing method.

Conventionally, in order to manufacture molds at high speed, a shell molding method has been used in which so-called coated sand, which is a refractory granular aggregate coated with a phenol novolac resin, is filled into a mold and heat-cured.

However, in order to save energy during mold manufacturing, improve mold production speed, and improve the quality of molds and castings, gas is added to harden them through a chemical reaction at room temperature. The foundry industry is seriously considering its introduction as a law.

The ffl cold box method includes the so-called furan cold box method, in which acid-curable resins such as furan resin are cured with sulfur dioxide* using peroxide as an oxidizing agent, and the so-called furan cold box method, in which acid-curable resins such as furan resin are cured with sulfur dioxide*, and polyols and polyinocyanates are cured in an aerosol form. There is a urethane cold box method that uses grade amine as a catalyst for curing.

Of these, the Furan cold box method, which uses a 7-run resin chemically the same as Furan's self-hardening resin, has been rapidly attracting attention recently, and has been proven to have good results in the field of high-mix, low-volume mechanical casting.

The furan cold box method uses furan resin, which is one of the heat-resistant organic binders, and has many other advantages, including superior quality of the resulting castings.

One type of pot life book is that the curing reaction will occur for a short period of time (referred to as pot life) unless sulfur dioxide comes into contact with a mixed material made by adding and kneading acid-curing resin and peroxide composition to fire-resistant granular aggregate. ) is long.

However, the pot life is not infinite but limited, and as the effective peroxide content of the peroxide composition decomposes and becomes inactive,
When sulfur dioxide is injected, the main curing reaction does not occur, making it unusable. The biggest factor in the decomposition and deactivation of peroxides is the metals and metal oxides contained in the refractory granular aggregate.

Metal salt, alkaline content.

The present inventors were able to suppress the decomposition and deactivation of peroxide by treating these components contained in the refractory granular aggregate with a stabilizer, thereby extending the usable life and reducing the crosstalk. We have discovered that it is possible to eliminate waste and further rationalize products, and have arrived at the present invention.

That is, in the present invention, after molding a mixture of refractory granular aggregate, acid-curing resin, and peroxide composition and then injecting gaseous or aerosol sulfur dioxide to produce a mold, When preparing the kneaded material, the refractory granular aggregate is first mixed with β-diketone homologs, oxine homologs, nitrosonaphthol homologs, thiol homologs, oxime homologs, nitroso compounds, aralintricarboxylic acid homologs, and α-dithion homologs. The stabilizer used in the present invention relates to a method for producing a curable mold, which is characterized in that at least one stabilizer is added thereto, and then an acid-curable resin and a peroxide are added and mixed. Examples include β-diketo hepta-groups such as acetylacetone, dipivaloylmethane, and bis-7tylacetone.

Oxine, 2-methyloxine, oxine congeners such as 5,7-dibromooxine, nitrosonaphthol congeners such as 1-nitroso-2-naphthol, 4-methyl-2-nitroso-1-naphthol, bismuthiol II, 2
- thiol congeners such as mercaptobenzodeazole,
Oxime congeners such as dimethylglyoxime, salicylaldoxime, α-benzoin oxime,
At least one of nitroso compounds such as No. 7, aurintricarboxylic acid analogs such as aluminone, and α-dithion analogs such as didiooxamide.

In the present invention, the stabilizer is typically a refractory granular aggregate 10
0 parts by weight. Old ~ 1 heavy view part preferred 1-kuke 0.05
~0.5 part by weight is used. Furthermore, when using a peroxide composition containing hydrogen peroxide as the main component, it is likely to be decomposed and deactivated by metals and other foreign substances in the refractory granular aggregate.
The pot life of mixed materials was short, and in practical use 1/C@ was used, but by adopting the method of the present invention, the pot life can be adjusted to a significantly longer pot life, and an inexpensive hydrogen peroxide composition can be obtained. In addition, green sand-type recycled sand containing many clay minerals has a pI (pI) greater than 6, and as a result of bentonite sintering on the surface of the alkaline and fire-resistant granular aggregate, metals and metal oxidation The method of the present invention is also useful in this respect, since it is easy to fix objects and particularly shorten the pot life.

EXAMPLES In order to explain the present invention more specifically, Examples will be described below, but the present invention is not limited to the Examples.

Examples 1 to 7 and Comparative Example 1 1.5 parts by weight of the stabilizer shown in Table 1 was added to 1,000 parts by weight of Enshu water-washed sand and kneaded, followed by 16 parts by weight of 7-run resin and 60% hydrogen peroxide solution. After adding and kneading 2.5 parts by weight, the mixture was left to stand and economically filled into a mold, and then sulfur dioxide was added for 1 second and compressed air was passed for 5 seconds [7] to measure the strength of the molded mold immediately after molding. The shelf life (pot life) of the mixture was investigated. The results are shown in Table 1.

Table 1 Examples 8 to 14 and Comparative Examples 2 to 3 1.5% of the stabilizer shown in Table 2 was added to 1,000 parts by weight of Enshu water-washed crushed sand. 1 parts of mixed wire 1-2, then 14 parts by weight of furan resin and 2.5 parts by weight of 60% hydrogen peroxide solution. 5 yellow for 1 second and compressed air for 5 seconds, the strength of the mold was measured immediately after molding, and the shelf life (pot life) of the mixture was investigated.The results are shown in Table 2.

Claims (1)

[Claims] 1. After molding a mixed wire obtained by adding and kneading acid-curable 4 fats and peroxide composition to fire-resistant granular aggregate, gaseous or aerosol sulfur dioxide is injected to produce a mold. When preparing the kneaded material, β-diketone congeners, oxine congeners, nitrosonaphthol congeners, diol congeners, oxime congeners, nitrone compounds, aralintricarboxylic acid congeners, α - addition of at least 1r/4 stabilizer among didione homologues, then acid curable 4
A method for producing curable n-type, which is characterized by adding and kneading N fat and a harsh substance. 2. The amount of stabilizer added is 0.1 to 1 part by weight per 100 parts by weight of the fire-resistant granular aggregate/l? The manufacturing method according to claim 1. 3. Claim 2, wherein the amount of the stabilizer added is 0.05 to 0.5 parts by weight per 100 parts by weight of the fire-resistant granular aggregate.
Manufacturing method described in section. 4. The manufacturing method according to any one of Items 1 to 3, in which a peroxide containing hydrogen peroxide as a main component is used in part or in whole. 5. The manufacturing method according to any one of claims 1 to 4, wherein a fire-resistant granular aggregate whose p)I is greater than 6 is used.