JPH0325254B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a curable mold composition that is used when molding a mold by adding gaseous or aerosol sulfur dioxide to a sand mold made by adding and kneading an acid-curable resin and a peroxide composition to a granular refractory material. The present invention relates to peroxide compositions, and in particular to improvements in peroxide compositions. Conventionally, when manufacturing cores and main molds at foundries, mold manufacturing methods using furan self-hardening binders have been used due to the reduction of industrial waste pollution, rationalization of productivity, improvement of casting quality, and various other advantages. It has come to be widely used, replacing manufacturing methods that use inorganic binders such as water glass and cement. However, mold manufacturing methods using furan self-hardening binders also have some drawbacks. One of them is that the curing time is long, and it takes about 10 minutes to several hours to manufacture a mold, making it unsuitable for high-speed mold manufacturing. Conventionally, in applications for manufacturing molds at high speed, a cloning method has been used in which so-called coated sand, in which a granular refractory material is coated with a phenolic novolak resin, is thermally cured. However, in order to save energy, speed mold production, and streamline the mold manufacturing process, the casting industry is seriously considering introducing the so-called cold box method, which involves gas curing at room temperature, as an alternative method. Currently, cold box methods include the so-called furan cold box method, in which acid-curing resins such as furan resin are cured with sulfur dioxide using peroxide as an oxidizing agent, and polyols and polyisocyanates are cured using an aerosol of tertiary amine as a catalyst. There is a urethane cold box method that hardens, and the Franco cold box method, which has been proven to have good results in the production of castings due to its self-hardening properties, has recently been rapidly attracting attention. However, there are several points to be improved in the Franco Cold Box method, among which are improvements in cost and safety due to peroxides. Currently, as peroxides, compositions mainly composed of ketone peroxides such as methyl ethyl ketone peroxide or compositions mainly composed of aromatic hydroperoxides such as cumene hydroperoxide are generally used. All of these peroxide compositions are expensive and there is a need to further improve their safety. Hydrogen peroxide is an inexpensive and highly safe peroxide, but it has not been put to practical use because it decomposes due to impurities in the granular refractory material, has a short useful life for the kneaded product, and has low mold strength. Hydrous ketone peroxides are also commercially available, but they can be used to react acid-curing resins using polyols such as glycerin, cellosolve, nitrogen-containing water-soluble compounds such as pyrrolidone, etc. as homogenizing agents that also serve as dilution stabilization. is delayed and is practically unusable. As a result of extensive research, the present inventors have discovered a water-containing organic peroxide composition that is inexpensive, highly safe, and satisfactorily performs well as a peroxide for Francold boxes, and has thus arrived at the present invention. That is, the present invention is used when manufacturing a mold by adding gaseous or aerosol sulfur dioxide to a sand mold made by adding and kneading an acid-curing resin and a peroxide composition to granular refractory aggregate. A composition comprising a water-soluble monocarboxylic acid, a water-soluble hydroxy mono- or polycarboxylic acid, an acidic alkali metal or water-soluble monoalcohol compound of a polycarboxylic acid or a hydroxypolycarboxylic acid as a peroxide composition. , a curable template characterized by using a water-containing ketone peroxide composition containing at least one member selected from the group of water-soluble lactone compounds, water-soluble ketone compounds, and water-soluble ether ester compounds as a dilution stabilizer. This relates to a composition. According to the present invention, it is possible to provide a curable mold composition that is inexpensive, safe, and functionally excellent. The dilution stabilizer used in the present invention is a homogenizing agent that also serves as dilution stabilization, and does not delay the curing reaction of the acid-curable resin. Hydroxy monocarboxylic acid has 1 to 6 carbon atoms, hydroxy polycarboxylic acid has 2 to 6 carbon atoms, polycarboxylic acid or acidic alkali metal salt of hydroxy polycarboxylic acid has 2 to 6 carbon atoms, and is water soluble. The water-soluble monoalcohol preferably has 1 to 6 carbon atoms, and the water-soluble ketone compound preferably has 4 to 7 carbon atoms, and at least one of these is used. If the carboxylic acid or alcohol has 7 or more carbon atoms, layer separation of the ketone peroxide composition will occur, which is not preferable. Further, in water-soluble ketone compounds, when the number of carbon atoms is 3 or less, the volatility is high, and when the number of carbon atoms is 8 or more, layer separation occurs, which is not preferable. As the ketone peroxide, at least one type of aliphatic ketone peroxide having 4 to 7 carbon atoms or alicyclic ketone peroxide having 6 to 8 carbon atoms is used. Aliphatic ketone peroxides having less than 3 carbon atoms pose a safety problem, while those having more than 8 carbon atoms are unsuitable because the active oxygen ratio decreases and curing is delayed. Similarly, among alicyclic ketone peroxides, those having less than 5 carbon atoms pose a safety problem, and those having more than 9 carbon atoms are unsuitable because the active oxygen ratio decreases and curing is delayed. Furthermore, the hydrous ketone peroxide composition has a dilution stabilizer in a range of 20 to 60% by weight and a water content in a range of 5 to 25% by weight. If the dilution stabilizer content is less than 20%, there is a safety problem and the desired effect of the present invention cannot be obtained. On the other hand, if it exceeds 60%, the curing speed becomes slow, which is unsuitable. Also, if the water content is less than 5%, the safety will decrease, and if it is more than 25%, the curing speed will be slow, which is inappropriate. In the present invention, two or more of the above-mentioned dilution stabilizers can be used in a mixture in any ratio. As the granular refractory aggregate, silica sand containing quartz as a main component, zircon sand, chromite sand, etc. are used, but the present invention is not limited to these. Further, as the acid-curable resin, furan resin, phenol resin, urea resin, melamine resin, or a copolymer or mixed resin thereof may be used, but the present invention is not limited thereto. usually,
100 parts by weight of granular fire-resistant aggregate and 0.5 to 3 parts of acid-curing resin
parts by weight, 0.1 to 2 parts by weight of peroxide composition are used. EXAMPLES In order to explain the present invention in more detail below, the advantages of the present invention will be described using examples, but the scope of the present invention is not limited by the following examples. Examples 1 to 5 and Comparative Examples 1 to 3 Hydrous methyl ethyl ketone containing 1000 parts by weight of Australian flattery silica sand, 15 parts by weight of furan resin, 10% active oxygen, 15% water, and 45% dilution stabilizer. A mixture prepared by adding 5 parts by weight of a peroxide composition and kneading was blown into a 25 x 25 x 250 m/m mold with pressurized air to fill it, and then sulfur dioxide gas was poured into the mold filled with the mixture. After pouring, the mold was washed with clean air and molded. The flexural strength of the molded mold was measured over time to examine the oxidizing ability of the peroxide composition. The results are shown in Table-1.

【table】

[Table] Examples 6 to 10 and Comparative Examples 4 to 5 Active oxygen is 9%, water is 10%, dilution stabilizer
Using hydrous methyl isobutyl ketone peroxide containing 45% and a mixture of two kinds of diluted stabilizers, 50φ
Molding was carried out in the same manner except that a 50 m/mH mold was used. Immediately after molding, the mold was placed on a 10-mesh sieve and vibrated for 1 minute using a rotary shaking sieve to measure the surface stability of the mold. The results are shown in Table-2.

【table】

【table】

Claims (1)

[Claims] 1. When manufacturing a mold by adding gaseous or aerosol sulfur dioxide to a sand mold made by adding and kneading an acid-curing resin and a peroxide composition to granular refractory aggregate, A composition used, comprising: a granular refractory aggregate;
It consists of 0.5 to 3 parts by weight of an acid-curing resin and 0.1 to 2 parts by weight of a peroxide composition per 100 parts by weight, and the peroxide composition is a water-soluble monocarboxylic acid, a water-soluble hydroxy mono- or polycarboxylic acid, Dilution stable compound consisting of at least one selected from the group of acidic alkali metal salts of polycarboxylic acids or hydroxy polycarboxylic acids, water-soluble monoalcohol compounds, water-soluble lactone compounds, water-soluble ketone compounds, and water-soluble ether ester compounds. A curable mold composition characterized in that it is a hydrous ketone peroxide containing 20 to 60% by weight of a curing agent and 5 to 25% by weight of water. 2. The curable mold composition according to claim 1, wherein the water-soluble hydroxymonocarboxylic acid has 1 to 6 carbon atoms. 3 Hydroxy polyhydric carboxylic acid has 2 to 6 carbon atoms
The curable mold composition according to claim 1. 4. The curable mold composition according to claim 1, wherein the acidic alkali metal salt of polycarboxylic acid or hydroxy polycarboxylic acid has 2 to 6 carbon atoms. 5. The curable mold composition according to claim 1, wherein the water-soluble monoalcohol has 1 to 6 carbon atoms. 6. The curable mold composition according to claim 1, wherein the water-soluble ketone compound is an aliphatic ketone having 4 to 7 carbon atoms. 7. Any one of claims 1 to 6, wherein the ketone peroxide is at least one of an aliphatic ketone peroxide having 4 to 7 carbon atoms or an alicyclic ketone peroxide having 6 to 8 carbon atoms. The curable mold composition according to item (1).