JPS60145235A - Hydrogen peroxide composition for casting mold - Google Patents

Abstract

PURPOSE:To provide a titled compsn. which is inexpensive and is highly safey by using hydrogen peroxide and water-insoluble org. compd. which are emulsified to a W/O type by a surface active agent as an essential component of a peroxide compsn. for a curable casting mold. CONSTITUTION:An acid curable resin and peroxide compsn. are added and kneaded to refractory granular aggregate and the mixture is kneaded and molded to a sand mold into which gaseous sulfur dioxide is introduced to produce a casting mold. The hydrogen peroxide compsn. for the casting mold consisting essentially of the hydrogen peroxide soln. and water-insoluble org. compd. which are emulsified and dispersed to a W/O type by a surface active agent is used as the peroxide compsn. in this stage. At least one kind among aliphat. hydrocarbon, arom. hydrocarbon, alicyclic hydrocarbon, etc. are used for the water-insoluble org. compd. and the surface active agent contg. essentially at least one kind of a nonionic surface active agent is used for the surface active agent. The average HLB thereof is preferably in a 3-7 range.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oxidizing agent used in forming a mold by adding sulfur dioxide to a granular refractory aggregate mixture to which an acid-setting resin and an oxidizing agent have been added.

More particularly, the present invention relates to certain aqueous organic peroxide compositions for use as oxidizing agents for curable molds.

Conventionally, for high-speed mold production applications such as automobile castings, the cloning method, which uses Novo Futatsukuya phenolic resin as a binding agent and heat-cures it, or the hot-box method, which heats and cures liquid phenolic resin or furan-based resin, has been widely used. It has been used extensively.

All of these materials are normally baked and hardened at 200°C to 500°C, which causes problems such as energy consumption, hardening time, distortion of the mold, poor dimensions of the casting due to deformation, and a poor working environment.

In recent years, the so-called cold box method, in which a mold is formed by blowing a gaseous or aerosol-like substance at room temperature, has been attracting attention and becoming popular as a molding method that improves these drawbacks.

As a cold box method, there is a urethane-based cold box method in which curing is performed using a polyol compound and a polyincyanate as a binder and a tertiary amine as a catalyst. However, in the urethane cold box method, a mixture of granular refractories containing polyol and poly, incyanate undergoes a gradual curing reaction even if left to stand, resulting in a short pot life or soot defects. There are disadvantages such as many casting defects such as gas defects.

Another cold box method currently available is an acid curing cold box method in which an acid curing resin and an oxidizing agent are added to granular refractories, and then sulfur dioxide is blown into the refractory to form a mold.

In this method, the curing reaction does not proceed unless the granular refractory mixture and sulfur dioxide come into contact with each other, so the pot life of the mixture is long, and acid-curing resins with excellent heat resistance, such as furan-based resins, are used as the binder. Because of this, there are fewer casting defects, etc.
There is a point.

However, this 802 cold box requires the use of an expensive organic peroxide as an oxidizing agent, and there is also the problem of concerns about the safety of organic peroxides. Oxides are required.

In addition, hydrogen peroxide is an inexpensive and highly safe peroxide, but hydrogen peroxide decomposes due to alkaline earth gold 14 oxide and other impurities contained in the granular refractory mixture. The usable time after mixing the mixture obtained by adding and kneading the IK resin and peroxide, the so-called pot life, is so short that it is practically unusable.

Under such circumstances, the inventor of the present invention has conducted intensive research and developed a method to remove hydrogen peroxide in order to prevent direct contact with impurities such as alkali contained in the fire-resistant aggregate, which causes the decomposition of hydrogen peroxide. It was discovered that by protecting it with a water-soluble organic compound, a hydrogen peroxide composition for hardenable molds that is inexpensive, highly safe, and has excellent performance can be obtained, and the present invention was completed. be.

That is, the present invention provides #li! to the refractory granular aggregate. A peroxide composition for producing type #I4 by introducing gaseous or aerosol sulfur dioxide into a sand mold formed by molding a mixture obtained by adding and kneading a peroxide composition and a peroxide composition. Hydrogen oxide water and water-insoluble organic compounds using surfactants! D Wlo
This relates to a hydrogen peroxide composition for molds whose main component is emulsified or dispersed in m.

The water-insoluble organic compounds used in the present invention are aliphatic hydrocarbons, aromatic hydrocarbons, alicyclic hydrocarbons, mono- or polyvalent aliphatic carboxylic acid esters, mono- or polyvalent aromatic carboxylic acid esters, Alternatively, at least one of polyvalent alicyclic carboxylic acid esters, phosphoric acid esters, and silicone oils may be used, and using these as a medium, hydrogen peroxide is used as a surfactant and water in mustard oil (W10J
By making the mold into an emulsified or dispersed type, a hydrogen peroxide composition whose surroundings are preserved by an oily component can be obtained, which can prevent contact with impurities in the fire-resistant aggregate, and when resin and peroxide are added. , the pot life of the kneaded mixture can be extended.

More preferably, the emulsified or dispersed hydrogen peroxide composition of the present invention contains, as a protective colloid, a water-soluble polymer compound such as carbomethoxy heptalulose, hydroxyethyl heptylulose, polyacrylic acid, sodium pyrophosphate % acid phosphoric acid ester, The use of a hydrogen peroxide stabilizer such as ethylenediaminetetraacetic acid will greatly extend the pot life, but is not limited to this.

The surfactant is preferably one containing at least one nonionic surfactant as a main component.

Average HLB of 1 m or 2 or more surfactants used
(In terms of hydrophilicity and lipophilicity parameters, the larger the HLB, the higher the hydrophilicity, and the smaller the HLB, the higher the lipophilicity.) is 3
Those in the range of ~7.

More preferred.

A suitable emulsified or dispersed hydrogen peroxide composition is hydrogen peroxide 10% by weight, preferably 20-35% by weight, and water-insoluble organic compound 30-7% by weight.
0% by weight, preferably 60% by weight of 40S, surfactant 0.
1 to 10% by weight, preferably 0.5 to 5% by weight,
The composition contains about 5 to 30% by weight of water.

Usually, 4 to 20 parts by weight of an acid-curing resin and 1 to 10 parts by weight of a hydrogen peroxide composition are added to 1000 parts by weight of fire-resistant granular aggregate, and the mixed mixture is molded into a sand mold to form a gaseous or aerosol. After introducing sulfur dioxide, excess sulfur dioxide is pressurized and removed with fresh air to produce a mold.

EXAMPLES Examples will be described below to explain the present invention in more detail, but the scope of the present invention is not limited to the following Examples.

Examples 1 to 6 and Comparative Example 1 Suienshu Silica Sand 1000. After adding and kneading 10 imaginary parts of the hydrogen peroxide composition shown in Table 1, 14 parts by weight of furan resin to ii parts, the mixture was left to stand for a certain period of time to form a mixture of 5oφX50'
The shelf life (pot life) of the mixture was investigated by filling a mold of XjH and blowing sulfur dioxide for 1 second and compressed air for 5 seconds to measure the strength of the mold immediately after molding. Table 1 shows the results.
Shown below.

Claims (1)

[Scope of Claims] t. A mold is manufactured by introducing gaseous or aerosol sulfur dioxide into a sand mold formed by molding a mixture obtained by adding and kneading an acid-curing resin and a peroxide composition to fire-resistant granular aggregate. - A hydrogen peroxide composition for molds, the main component of which is a peroxide composition obtained by emulsifying or dispersing peroxide-based water and a water-insoluble organic compound in a fiWO type using a surfactant. . 2 The water-insoluble organic compound is an aliphatic hydrocarbon, aromatic hydrocarbon, alicyclic hydrocarbon, mono- or polyvalent aliphatic carboxylic acid ester, mono- or polyvalent aromatic carboxylic acid ester, mono- or polyvalent alicyclic hydrocarbon The composition according to claim 1, which is at least one of a carbo/acid ester, a phosphate ester, and a silicone oil. The parent surfactant is at least one nonionic surfactant.
3. The composition according to claim 1 or 2, which contains seeds as a main component. 4. Average H of one type of surfactant or a mixture of 2 m or more
Claims 1 to 3 in which LB is in the range 3 to 7
A composition according to any one of paragraphs. 5. Any one of claims 1 to 4 containing 10 to 40% by weight of hydrogen peroxide, 30 to 70% by weight of a water-insoluble organic compound, and 0.1 to 10% by weight of a surfactant. The composition described in Section.