JPH0620582B2 - Peroxide composition for mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an oxidizing agent used when sulfur dioxide is added to a granular refractory aggregate mixture containing an acid-curable resin and an oxidizing agent to form a mold. It is about. More specifically,
The present invention relates to a specific aqueous organic peroxide composition used as an oxidizing agent for the acid-curable mold.

[Conventional technology]

Conventionally, for high-speed mold production applications typified by automobile castings, a cloning method in which a novolac type phenolic resin is used as a binder and heat curing, or a hot box method in which a liquid phenolic resin or furan resin is heat cured is generally used. Has been used. All of these are 200-300 ℃
It is usual to bake and harden it, and as a result, there are various problems such as energy consumption, hardening time, mold distortion, dimensional defect of casting due to deformation, working environment and the like.

In recent years, a so-called cold box method, in which a gaseous or aerosol substance is blown at room temperature to form a mold, has been drawing attention and spreading as a molding method for improving these difficulties.

As a cold box method, there is a urethane cold box method in which a polyol compound and polyisocyanate are used as a binder and cured with a tertiary amine as a catalyst. However, in the urethane cold box method, even when the granular refractory mixture to which the polyol and polyisocyanate are added is left standing, the curing reaction gradually proceeds, and the usable time of the mixture is short, or soot defects, gas defects, etc. There are problems such as many casting defects. At present, another cold box method is an acid-curable cold box method in which an acid-curable resin and an oxidizing agent are added to a granular refractory material, and then sulfur dioxide is blown to mold a mold.

[Problems to be solved by the invention]

In this method, the curing reaction does not proceed unless the particulate refractory mixture and sulfur dioxide come into contact with each other, so that the mixture has a long pot life, and an acid-curable resin excellent in heat resistance represented by a furan resin is used as a binder. Therefore, there are advantages such as less casting defects. However, this acid-curable cold box method requires the use of an expensive organic peroxide as an oxidant, and there is a concern that the stability of the organic peroxide is uncertain. Oxide is required.

In addition, hydrogen peroxide solution is mentioned as an inexpensive and highly safe peroxide, but the hydrogen peroxide solution is easily decomposed by the alkali content, metal oxide, and other impurities contained in the granular refractory aggregate, The usable time after mixing of the mixture obtained by adding the resin and the peroxide to the refractory aggregate and kneading, the so-called usable time is short and practically unusable.

Further, in this acid-curable cold box method, when a mold is repeatedly molded, so-called stain, which is a cured product of a resin, adheres to and is laminated on the mold, and cleaning is difficult, so a binder with less stain is required. ing.

[Means for Solving Problems] Under such circumstances, the present inventors have earnestly studied, and as a result, they are inexpensive, highly safe, and excellent in performance. In particular, when the mold is repeatedly molded, it adheres to a mold and The present invention has led to the invention of a peroxide composition for a curable mold, which has less cling to be laminated.

That is, the present invention is a peroxide composition used as an oxidizing agent when a gaseous refractory aggregate mixture containing an acid-curable resin and an oxidizing agent is injected with sulfur dioxide in a gaseous or aerosol state to produce a mold. Water-containing ketone peroxide composition having a water content of 5% by weight or more and less than 20% by weight, a dilution stabilizer of 15-40% by weight, and a dilution stabilizer / water weight ratio of 1-8. The present invention relates to a peroxide composition for a template, which is characterized by being a product.

Usually, a ketone peroxide composition reacts with a hydrogen peroxide solution using a mineral acid such as sulfuric acid as a catalyst, an aliphatic or alicyclic ketone, and an aliphatic or aromatic dibasic acid diester as a carrier agent in a dropping reaction under cooling to react. After completion, the aqueous layer is separated, and the non-aqueous layer is neutralized, washed, dried, and purified to produce a non-aqueous peroxide composition. This product has a complicated manufacturing process and takes man-hours, and when considering the amount of raw material charged, the yield also significantly decreases,
Not only is it expensive, but it is also non-aqueous, which poses a danger.

On the other hand, there are polyhydric alcohols such as glycerin, water-containing homogenized ketone peroxide compositions using nitrogen-containing water-soluble solvents such as N-methyl-2-pyrrolidone as a carrier agent,
These carrier agents serve as a curing retarder for the acid-curable resin and are inexpensive and highly safe, but when used as an oxidizing agent for the acid-curable cold box method, they cause mold curing failure and are practically unusable.

The peroxide composition of the present invention improves these problems, does not contain a solvent that serves as a curing retarder for homogenization, contains a dilution stabilizer, and contains water, so that the acid-curable cold box method It has excellent performance as an oxidant, does not require a complicated manufacturing process, is inexpensive, and because it is water-containing, it is excellent in safety such as fire, and it provides practically satisfactory results. is there.

As a preferred method for producing the hydrous ketone peroxide composition of the present invention, at least one of an aliphatic ketone having 3 to 8 carbon atoms or an alicyclic ketone having 6 to 10 carbon atoms is hydrogen peroxide in the presence of an acid catalyst. This is a method in which a ketone peroxide formed by oxidation into water and a dilution stabilizer are mixed without separating water during or after production.

As the dilution stabilizer used in the present invention, the following [I]-
One or more compounds of the formula [XI] can be mentioned.

[I]

(In the formula, n is 1 to 3, and when n = 1, X is an alkyl group, alkenyl group, alkyl group, cycloalkyl group, aryl group or aralkyl group having 1 to 20 carbon atoms.

When n = 2, X is an alkylene group having 2 to 20 carbon atoms, an alkenylene group, an alkynylene group, a cycloalkylene group, a phenylene group, an alkylene group, or an alkyl-substituted product thereof.

When n = 3 For n = 1 to 3, all R ₁ may be the same or different, alkyl group of the sum of all the number of carbon atoms of R ₁ is N～60, alkenyl group, alkynyl group, cycloalkyl group, aryl group, aralkyl A group, or a halogen, alkoxy, acyloxy or alkoxycarbonyl substitution product thereof. ) [II] (In the formula, m is an integer of 1 to 300.

Y is an alkylene group having 2 to 20 carbon atoms, an alkenylene group, an alkynylene group, a phenylene group or an alkylene group.

R ₂ and R ₃ may be the same or different and each is an alkyl group, an alkenyl group, an alkyl group, a cycloalkyl group, an aryl group or an aralkyl group having a total of 1 to 20 carbon atoms. R ₃ further includes a hydrogen atom and an acyl group. ) [III] Glycerin esters (In the formula, R ₄ , R ₅ and R ₆ are a hydrogen atom or an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an aryl group or an aralkyl group having a total of 1 to 60 carbon atoms.

However, at least one of R ₄ , R ₅ , and R ₆ is not a hydrogen atom. ) [IV] Phosphorus ester (In the formula, R ₇ , R ₈ and R ₉ are a hydrogen atom, or an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group having 1 to 20 carbon atoms, or a halogen, alkoxy or acyloxy substitution product thereof. However, at least one of R ₇ , R ₈ and R ₉ is not a hydrogen atom.) [V] (In the formula, R ₁₀ and R ₁₁ are an alkyl group, an alkenyl group, or an alkynyl group having 1 to 20 carbon atoms.) [VI] (In the formula, each of R ₁₂ and R ₁₃ is an aliphatic carbon-hydrogen group having 18 or less carbon atoms or a hydrogen atom.) [VII] Each of the substituents on the benzene ring is a methoxy group, an aldehyde group or a nitro group. Alternatively, two or more or two or more aromatic compounds.

[VIII] An aliphatic hydrocarbon having 5 to 18 carbon atoms.

[IX] Saturated fatty acid having 1 to 22 carbon atoms or 5 to 22 carbon atoms
Unsaturated fatty acids.

[X] An alicyclic carboxylic acid having 5 to 40 carbon atoms.

[XI] Frifuryl alcohol, phenolic compounds, aliphatic aldehyde compounds, furfuryl alcohol / formalin polycondensates, phenolic compounds / formalin polycondensates, urea / formalin polycondensates, melamine / formalin condensates.

The peroxide composition of the present invention contains a water content of 5% by weight or more and less than 20% by weight, a dilution stabilizer of 15-40% by weight, and a weight ratio of the dilution stabilizer / water is 1-8.

If the water content is less than 5% by weight, the amount of stains (cured product of resin) attached to and laminated on the mold during repeated molding of the mold is increased, which causes trouble in molding. On the other hand, when the water content exceeds 20% by weight, water is essentially a retarder of this reaction, and the curing rate becomes so slow that it cannot be practically used. According to the present invention, the presence of water in an appropriate amount suppresses the curing reaction, softens the stains, facilitates cleaning, and transfers the stains once attached to the mold to the mold, thereby extending the number of moldings. Next, when the proportion of the dilution stabilizer is less than 15% by weight, the ketone peroxide becomes unstable, and the tendency of spontaneous decomposition becomes faster.
The risk is significantly increased. On the other hand, it is not necessary to use more than 40% by weight. Further, if the weight ratio of the dilution stabilizer / water is less than 1, there will be a lot of stains attached to and stacked on the mold during repeated molding of the mold, which will hinder the molding. Also, the stains become hard and cleaning becomes difficult. On the other hand, when it is 8 or more, water is likely to be separated, and more stains are caused, which hinders molding.

In addition to the above essential components, the composition of the present invention may contain a nonionic or anionic surfactant.

Usually, when molding a mold, zircon sand or chromite sand is used as the granular refractory aggregate in addition to silica sand containing silica as a main component, but the present invention is not particularly limited to this. Examples of the acid-curable resin include furan resin, phenol resin, urea resin, melamine resin or co-condensates or mixtures thereof, and these resins are usually 5 to 20 parts by weight with respect to 1000 parts by weight of the granular refractory aggregate. Part used. The peroxide composition of the present invention is usually used in an amount of 3 to 10 parts by weight based on 1000 parts by weight of aggregate.

〔Example〕

Hereinafter, examples will be described to describe the present invention in more detail, but the scope of the present invention is not limited by these examples.

Examples 1 to 5 and Comparative Examples 1 to 3 To 100 parts by weight of silica sand, 15 parts by weight of furan resin, 0.5 parts by weight of a peroxide composition consisting of a ketone peroxide shown in Table 1, a dilution stabilizer and water are added. The kneaded sand mixture was blown with a horizontal splitting automatic molding machine at an air pressure of 3.0 kg, then sulfurous acid gas was injected, and excess gas was washed with pressurized fresh air to repeatedly mold the mold.

The number of times of repeated molding was measured until the operation failure occurred as a result of adhesion of model contamination (staining) to the mold extrusion pin.
The results are shown in Table 1.

Claims (3)

[Claims] 1. A peroxide composition used as an oxidizing agent when a gaseous or aerosol sulfur dioxide is injected into a granular refractory aggregate mixture containing an acid-curable resin and an oxidizing agent to produce a mold. And water content of 5% by weight or more and 20% by weight
Peroxide mixture for a template, which is a hydrous ketone peroxide composition containing less than 15 to 40% by weight of a dilution stabilizer and a dilution stabilizer / water weight ratio of from 1 to 8. Composition. 2. The method according to claim 1, wherein the ketone peroxide is at least one of an aliphatic ketone peroxide having 3 to 8 carbon atoms and an alicyclic ketone peroxide having 6 to 10 carbon atoms. Composition. 3. The composition according to claim 1, wherein the dilution stabilizer is one or more compounds represented by the following [I] to [XI]. [I] (In the formula, n is 1 to 3, and when n = 1, X is an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an aryl group or an aralkyl group having 1 to 20 carbon atoms. In the case, X is an alkylene group having 2 to 20 carbon atoms, an alkenylene group, an alkynylene group, a cycloalkylene group, a phenylene group, an alkylene group or an alkyl-substituted product thereof, where n = 3. For n = 1 to 3, all R ₁ may be the same or different, alkyl group of the sum of all the number of carbon atoms of R ₁ is N～60, alkenyl group, alkynyl group, cycloalkyl group, aryl group, aralkyl A group, or a halogen, alkoxy, acyloxy or alkoxycarbonyl substitution product thereof. ) [II] (In the formula, m is an integer of 1 to 300. Y is an alkylene group having 2 to 20 carbon atoms, an alkenylene group, an alkynylene group, a phenylene group or an alkylene group. R ₂ and R ₃ may be the same or different. Well, alkyl groups, alkenyl groups, alkynyl groups, all of which have 1 to 20 carbon atoms,
It is a cycloalkyl group, an aryl group or an aralkyl group. R ₃ further includes a hydrogen atom and an acyl group. ) [III] Glycerin esters (In the formula, R ₄ , R ₅ and R ₆ are a hydrogen atom or an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an aryl group or an aralkyl group having a total of 1 to 60 carbon atoms. At least one of R ₄ , R ₅ and R ₆ is not a hydrogen atom.) [IV] Phosphorus ester (In the formula, R ₇ , R ₈ and R ₉ are a hydrogen atom, or an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group having 1 to 20 carbon atoms, or a halogen, alkoxy or acyloxy substitution product thereof. However, at least one of R ₇ , R ₈ and R ₉ is not a hydrogen atom.) [V] (In the formula, R ₁₀ and R ₁₁ are an alkyl group, an alkenyl group, or an alkynyl group having 1 to 20 carbon atoms.) [VI] (In the formula, R ₁₂ and R ₁₃ are each an aliphatic hydrocarbon group having 18 or less carbon atoms or a hydrogen atom.) [VII] Each of the substituents on the benzene ring is a methoxy group, an aldehyde group or a nitro group. Alternatively, two or more or two or more aromatic compounds. [VIII] An aliphatic hydrocarbon having 5 to 18 carbon atoms. [IX] Saturated fatty acid having 1 to 22 carbon atoms or 5 to 22 carbon atoms
Unsaturated fatty acids. [X] An alicyclic carboxylic acid having 5 to 40 carbon atoms. [XI] Furfuryl alcohol, phenolic compound, aliphatic aldehyde compound, furfuryl alcohol / formalin polycondensate, phenolic compound / formalin polycondensate, urea / formalin polycondensate, melamine / formalin condensate.