JPH0557393A - Moldrelease agent for green sand used for casting - Google Patents

Abstract

PURPOSE:To provide moldrelease agent for green sand used for casting, which has excellent mold releasing property and stability, etc., and can be efficiently cast. CONSTITUTION:The moldrelease agent for green sand used to casting, is colloid solution prepared by stirring and mixing mixed liquid containing surfactant, fatty acid, amine and water into basic oil composed or mineral oil and/or petroleum solvent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a release agent used for molding a green sand mold used for casting.

[0002]

2. Description of the Related Art Generally, a sand mold is most often used as a mold in casting, and it is necessary to improve the demolding property between the model and the fresh sand and reduce the wear of the model during the molding work of the sand mold. There is. That is, there are types of molds, wood molds, resin molds, etc. in the model, the mold material is cast iron, aluminum, alloy, etc., the wood mold material is cedar, cypress, etc., and the resin mold material is epoxy resin, etc. Are used respectively. Since these models rub against raw sand when they are molded, they are greatly worn and the initial design dimensions change when continuously used, making it difficult to obtain accurate products. In addition, the close contact between the model and the green sand causes “mold bottom” and “demolding failure”. Therefore, a release agent is used to prevent the model from sticking to the green sand and to improve the slip.

The basic performance required for such a mold release agent for a green mold for casting is 1) forming a proper and uniform film to prevent the model and the green sand from sticking to each other. 2) To improve the smoothness of the raw sand so that it flows evenly onto the model. 3) Do not generate a large amount of gas when pouring the molten metal of the casting into the molded sand mold, and do not adversely affect the air permeability and strength of the sand mold. 4) The model should not corrode or dissolve. 5) Be inexpensive. Etc.

As a conventional release agent, an oil-based release agent prepared by dissolving a fatty acid, a wax, an ester, a fat and an oil, a surfactant and the like in a petroleum solvent is usually used. However, although kerosene is mainly used as the petroleum solvent, the viscosity of kerosene is generally about 1 to 3 cSt (40 ° C).
Therefore, when sprayed on the model, a thin oil film is not formed, and when the fresh sand is put and compressed, the oil film tends to be further thinned, and the model and the raw sand tend to adhere to each other. For this reason,
Number of times molding can be performed with a single release agent application (continuous molding times)
Will be less. In addition, the mold release performance decreases when the surface is dense, such as a resin mold or a mold plated with hard chrome to prevent abrasion of the model, or when the viscosity of the coating film decreases as the sand temperature rises. May occur. Furthermore, since kerosene has a low flash point, which is usually around 50 ° C, there is a risk of ignition, and it is subject to the regulations of the Fire Service Law, so it is necessary to exercise extreme caution when using it. On the other hand, use of petroleum-based mineral oil having a high viscosity and a high flash point can be considered as a method for improving these drawbacks, but these generally cause "mold loss" due to the high tackiness of the oil film.

In order to solve the problem of the above-mentioned mold release agent, a water-in-oil emulsion mold release agent (Japanese Patent Publication No. 63-29625).
No.) has been proposed and used. This is because the main component is the oil-soluble mold release agent having a flash point of 55 ° C. or higher among the above oily mold release agents, and if necessary, 10 to 60% of water is added using a surfactant, and the mixture is stirred and mixed in the oil. It is a release agent in the form of a water-based emulsion.

However, the above releasing agent has the following problems.

1) Since the emulsion is emulsified, the stability of the emulsion particles is lowered due to temperature fluctuation, and there is a risk of separation during long-term storage.

2) Since there is a difference in the density of the petroleum solvent used and water, it is necessary to make the emulsion uniform during production, and sufficient stirring cannot be performed by a simple method such as propeller stirring. Equipment is required. In the case of stirring with a propeller, a uniform emulsion cannot be obtained unless stirring is performed for 3 hours or more. If the size of the emulsion particles is not uniform, the particle size distribution tends to differ between the upper layer and the lower layer, and it becomes difficult to obtain uniform performance.

3) Since the amount of water is as large as 10 to 60%,
In the case of cast iron model, rust occurs due to the effect of residual moisture.

4) The raw sand used in the molding sand mold is mainly sand (mountain sand, river sand, beach sand, silica sand, etc.), binders (clay, bentonite, etc.), and additives (coal powder, pitch powder, coke powder). , Graphite powder, etc.). Regarding the binder in this, water is added to increase the cohesive strength, but when the amount of water added is large, the air permeability and strength, which are the necessary conditions for the sand mold, tend to decrease. Therefore, the water content is 2
About 8% is considered appropriate. However, with this water-in-oil emulsion type water content, excess water is likely to occur at the interface between the model and the green sand, the binding force of the binder decreases, and even if casting molding defects do not occur, the water will form on the model surface. There is a tendency for sand to remain. Further, in order to solve this, it is necessary to reduce the amount of application as much as possible, it takes time and effort to adjust the amount of spraying, and a device is required to prevent the binder from absorbing water.

Therefore, at present, there is a strong demand for the development of a new release agent that can solve the above problems.

[0012]

DISCLOSURE OF THE INVENTION It is an object of the present invention to provide a mold releasing agent for molding raw sand which has excellent demolding property, stability and the like and can be efficiently cast.

As a result of intensive studies to solve the above problems, the present inventors have found that the above object can be achieved by a colloidal solution having a specific composition, and have completed the present invention.

That is, the present invention is a colloidal solution obtained by stirring and mixing a mixed solution of a base oil comprising a mineral oil and / or a petroleum solvent with a surfactant, a fatty acid, an amine and water. The present invention relates to a mold release agent for green sand.

The present invention will be described in detail below.

As the base oil of the present invention, a mineral oil or a petroleum solvent is used alone, or both are used in combination. As the mineral oil, known mineral oils can be used, for example, various mineral oils such as machine oil and neutral oil (high-grade lubricating base oil) can be exemplified, and the petroleum-based solvent can also be known various petroleum light oils such as kerosene and light oil. Can be illustrated. The base oil preferably has a kinematic viscosity of 10 cSt or less from the viewpoint of sprayability and demoldability.

As the surfactant, known ones such as nonionic surfactants, anionic surfactants, cationic surfactants and amphoteric surfactants can be used, but especially nonionic surfactants and anionic surfactants. Activators are good, and examples of nonionic surfactants include higher alcohol alkylene oxide adducts, nonylphenol alkyl oxide adducts, fatty acid alkylene oxide adducts, glycerin fatty acid esters, polyalkylene glycol fatty acid esters, sorbitan fatty acid esters, and sorbitan fatty acid esters. Examples thereof include alkylene oxide adducts, fatty acid amides, alkylene oxide adducts of fatty acid amides, and polyethylene-polyoxypropylene condensates. Examples of the anionic surfactant include higher fatty acid, naphthenic acid, alkylsulfonic acid, alkylnaphthalenesulfonic acid, petroleum sulfonic acid, alkali salt of alkylbenzenephosphonic acid, amine salt of alkylbenzenephosphonic acid, and ammonia of alkylbenzenephosphonic acid. Examples thereof include salts, alkyl sulfates of alkylbenzenephosphonic acid, sulfated oils, sulfated aliphatic monoglycerides, sulfated alkanolamides, sulfated ethers and alkyl phosphates. The addition amount of these surfactants is preferably 2 to 10% by weight. If it is less than 2% by weight, a colloidal solution cannot be obtained sufficiently, and if it exceeds 10% by weight, the viscosity increases and the tackiness is exhibited, so that sufficient demolding property cannot be obtained.

As the fatty acid, a higher fatty acid having 8 or more carbon atoms is preferable, and for example, a direct fatty acid such as caprylic acid, pelargonic acid, capric acid, undecyl acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, etc. Chain unsaturated fatty acids, caproleic acid, undecylenic acid, lauroic acid, myristoleic acid, palmitoleic acid, oleic acid, linear unsaturated fatty acids such as elaidic acid, branched fatty acids such as isooctanoic acid, isononanoic acid, isostearic acid, wax, etc. Examples thereof include organic acids obtained by oxidation, resin acids such as abietic acid, dimer acids such as capric diacid, and various known fatty acids such as trimer acid. The added amount is preferably 0.5 to 2% by weight. If it is less than 0.5% by weight, there is no addition effect and "mold loss"
Occurs, and sufficient releasability cannot be obtained. On the other hand, when it exceeds 2% by weight, tackiness becomes excessively high, and in this case also sufficient releasability cannot be obtained. The fatty acid in the present invention is
It plays a role of improving demolding property.

As the amine, various known amines can be used, for example, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, mixed isopropanolamine, n-.
Alkanolamines such as propanolamine and triisopropanolamine, morpholine-based amine compounds such as morpholine, n-aminopropylmorpholine and n-alkylmorpholine, pyrrolidine, n-methyl-2hydroxyethylpyrrolidine, 2-hydroxymethylpyrrolidine and the like. Pyrrolidine-based amine compounds, piperazine, 1-
Amino-4methylpiperazine and other piperazine amine compounds, hexahydro 1,3,5 tri (2-hydroxyethyl) S-triazine, hexahydro 1,3,5 triethyl S-triazine, 6-phenyl-2,4-diamino Examples include triazine-based amine compounds such as triazine, cyclic amines such as cyclohexylamine and dicyclohexylamine, and aliphatic amines such as diisopropylamine, n-butylamine, isobutylamine, isoamylamine, and methylhexylamine. The addition amount thereof is preferably 0.02 to 1 part by weight with respect to 100 parts by weight of the mixed solution. If it is less than 0.02 part by weight, a sufficient colloidal solution cannot be obtained, and if it exceeds 1 part by weight, the reaction with fatty acid increases the tackiness and sufficient demolding property is not exhibited, which is not preferable. Addition of amine gives a colloidal solution with excellent stability. The colloidal solution referred to in the present invention means a solution showing a transmittance of 10% or more when the distilled water is taken as 100% at a wavelength of 524 nm in the transmittance measurement by a Bausch & Lomb type spectrophotometer.

Water is preferably added in an amount of 3 to 10% by weight. If the amount is less than 3% by weight, the strength of the coating film is lowered, and the demolding performance is almost the same as that of the oil-based releasing agent, and a sufficient effect cannot be obtained.
If it exceeds 10% by weight, the content of water in the raw sand will be too much, which will affect the caking force of the clay and cause the raw sand to remain in the model. Furthermore, it is not preferable that the mixed liquid becomes a colloidal solution and becomes an emulsion state.

In addition to the above components, various additives such as fragrances may be added if necessary. As an example of the method for preparing the release agent of the present invention, first, a predetermined amount of a fatty acid and a surfactant are added to a base oil and mixed so as to be homogeneous by propeller stirring, and then a predetermined amount of water is added to the mixture to make a uniform mixture. When a predetermined amount of amine is added when it has been mixed, the release agent of the present invention can be obtained. In this case, the mixing temperature can be prepared at room temperature if it dissolves at room temperature, but, for example, if the additive is solid at room temperature and requires heating, it is prepared at any temperature. In addition, the stirring time is
Usually, the colloidal solution of the present invention can be obtained after about 10 minutes to 1 hour. The stirring method is preferably performed with a homogenizer, but unlike the conventional case of producing a water-in-oil emulsion, the same effect can be obtained by a simple method such as propeller stirring.

In using the release agent of the present invention, for example,
A normal hand sprayer or an automatic spraying device may be used to spray the model used for molding the green sand mold.

[0023]

INDUSTRIAL APPLICABILITY The mold releasing agent of the present invention for casting raw sand can achieve excellent demolding property as compared with the conventional water-in-oil type emulsion mold releasing agent, and it itself has a simple propeller stirring. The product quality is constant because it is composed of fine particles, and stability and sprayability are excellent.
Furthermore, since the water content is low, the generation of rust can be effectively suppressed.

On the other hand, since it contains a certain amount of water as compared with the conventional oil-based mold release agent, it is less likely to catch fire, and when the base oil has a flash point of 80 ° C. or higher, the flash point is substantially It is not recognized in the above, and exerts an excellent effect in terms of safety.

[0025]

EXAMPLES Examples will be shown below to further clarify the characteristics of the present invention. However, the present invention is not limited to the examples.

All percentages in the examples and comparative examples are% by weight.

Examples 1 to 10 The components shown in Table 1 were used and mixed and stirred to prepare a colloidal solution, to prepare the release agent of the present invention.

The physical properties of the obtained releasing agent of the present invention were tested for stability, friction coefficient, transmittance, rustproofing property and releasing performance. The results are also shown in Table 1. The physical property test and the measurement were carried out by the following measuring methods.

A) Stability test: 200 ml of a mold release agent was put into a 200 ml beaker as a sample and left at room temperature for 24 hours. Then, the upper layer part and the lower layer part were sampled with a dropper, and the viscosity was measured. Lower layer viscosity / upper layer It was evaluated by the value of viscosity.

B) Friction coefficient: Measured at room temperature using a pendulum type oiliness tester type I.

C) Transmittance: Using a Bausch & Lomb type spectrophotometer, the transmittance at a wavelength of 524 nm was adjusted to 100% with distilled water, and the transmittance of the sample was measured. The appearance was also observed. d) Anticorrosion test: Test piece (FC-20, 20mm × 7
(0 mm x 5 mm) is completely immersed in the sample and then 50 ml of the sample
Put the test piece in a 100 ml beaker containing the water in a semi-immersed state, and leave it in a constant temperature and humidity chamber at a humidity of 90% and a temperature of 50 ° C for 1 hour to generate rust in the gas phase and the liquid phase. I confirmed the condition. The evaluation criteria are as follows.

(Vapor portion) A ... 10% or less thin rust occurs B ... 30% or less thin rust C ... less than 30% thick rust D ... 30% or more thick rust occurs (liquid Phase part) A ... No discoloration and rust generation B ... Gray discoloration C ... Black discoloration D ... Reddish brown discoloration (rust generation) e) Releasing performance test: The following tests I to III were performed. Molding is allowed when no molding defect such as residual sand on the model or mold drop is observed, and the number of continuous molding is shown in the table.

(Test I) Using a Jolt squeeze molding machine, a cast iron model of a joint was spray-coated for 1 second and then continuously molded.

(Test II) After spray coating for 3 seconds by the method of Test I, continuous molding was performed.

(Test III) A Jolt squeeze molding machine was used to spray-apply a resin model of a cutting machine tool for 1 second, followed by continuous molding.

[0036]

[Table 1]

[0037]

[Table 2]

Comparative Examples 1-2 A mold release agent was prepared in the same manner as in Examples using the components shown in Table 2, and its physical properties were tested. The results are also shown in Table 2.

Comparative Example 3 A physical property test was conducted in the same manner as in the examples using a commercially available mold release agent for oil-based foundry sand. The results are shown in Table 2.

[0040]

[Table 3]

From the above results, it can be seen that the releasing agent of the present invention exhibits extremely excellent performance as compared with the conventional one.

Claims (1)

[Claims] 1. A casting raw material, which is a colloidal solution obtained by stirring and mixing a mixed solution of a base oil comprising a mineral oil and / or a petroleum solvent with a surfactant, a fatty acid, an amine and water. Release agent for sand.