JPH06234990A - Undiluted release agent for forming greensand mold - Google Patents

Abstract

PURPOSE:To provide an undiluted release agent which is used in the form of an O/W emulsion after being diluted with water. CONSTITUTION:The release agent comprises, as the essential ingredients, a hydrocarbon oil as the main releasing component, a surfactant as a dispersant, and an anionic surfactant and/or a strongly basic amine as a wetting agent. This release agent is used in the form of an O/W emulsion after being diluted with water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a raw mold release agent stock solution containing a hydrocarbon-based oil as a main agent for mold release action and a mold release agent for raw mold making.

[0002]

The most primitive mold, the raw mold, is
Compared to other thermosetting, self-curing, and gas-curing molds, molding productivity is good, mold materials are inexpensive, and they can be used repeatedly. Mainstream of molds.

As a mold release agent for green molding, the same applicant as the applicant of the present application used a water-in-oil type in which a surfactant was used as a dispersant and a water phase was dispersed in a hydrocarbon oil phase ( W / O
(Type) emulsion systems have been proposed (see Japanese Patent Publication No. 63-29625).

[0004]

However, the above-mentioned type of release agent has the following problems.

(1) The emulsion form is water-in-oil (W /
Since it is type O), it cannot be diluted with water. For this reason, it was necessary to prepare the composition from the time of manufacture to the time of use, and transportation and storage were troublesome.

(2) Further, from the viewpoint of the stability and releasability of the liquid, the water content is limited to about 60%, which is not always sufficient from the viewpoint of resource saving and fire safety.

In this case, an oil-in-water (O / W) type emulsion may be used as the release agent, but it is difficult to form a uniform release film on the surface of the mold after it has been used for molding. Was said. The reason for this is that the main agent for releasing action is hydrocarbon oil, so oil remains on the surface of the mold (particularly the mold) after the release agent is applied and used for molding, and the water-based O / W
With a mold emulsion release agent, when applied to the mold surface,
This is because they will be repelled.

In view of the above, it is an object of the present invention to provide a release agent stock solution for green molding which can be diluted with water before use and used in the form of an O / W emulsion.

[0009]

The stock solution of a mold release agent for green molding according to the present invention solves the above problems by the following constitution.

A stock solution of a release agent for green molding containing a hydrocarbon-based oil as a release-acting main agent, which comprises a surfactant as a dispersant and a wettability improver in addition to the hydrocarbon-based oil. An anionic surfactant and / or a strongly basic amine as an essential component, and is diluted with water to be used as an oil-in-water emulsion.

[0011]

[Detailed description of means]

A. The precondition for the stock solution of the mold release agent for green molding of the present invention is to contain a hydrocarbon oil as a main agent for mold release action.

As the above-mentioned hydrocarbon-based oil, a petroleum-based oil having a flash point of 55 ° C. or higher is usually preferable from the viewpoint of handleability. Specific examples thereof include lubricating oil such as gear oil, machine oil, bearing oil, turbine oil, kerosene, and light oil. These can be used alone or in combination.

B. In addition to the hydrocarbon oil, a surfactant as a dispersant, and an anionic surfactant and / or a strongly basic amine as a wettability improver are contained as essential components, To do.

(1) The surfactant as the dispersant may be any of nonionic, anionic, cationic, and zwitterionic types, but in particular, the following nonionic types are oil drops in water during use. It is desirable from the viewpoint of liquid stability of the (O / W) type emulsion.

Nonionic surfactant: alkyl polyoxyethylene ether, alkylcarbonyloxy polyoxyethylene, p-alkylphenyl polyoxyethylene ether, NN-di (polyoxyethylene) alkane amide, fatty acid polyhydric alcohol ester, Fatty acid polyhydric alcohol polyoxyethylene, fatty acid sucrose ester, ethylene oxide adduct of castor oil.

The composition ratio of the surfactant as the dispersant is 1 to 50 parts (preferably 2 to 30 parts) with respect to 100 parts of the hydrocarbon oil. Less than 1 part, O /
It is difficult to prepare a W type emulsion, and even if it exceeds 50 parts, the effect does not increase in proportion to the amount.

(2) The following can be exemplified as the anionic surfactant and the strongly basic amine as the wettability improver.

Anionic surfactant: higher fatty acid alkali salt (soap), sodium alkyl sulfate, 2-alkyl sodium sulfate, sodium alkylbenzene sulfonate, sodium α-olefin sulfonate, sodium N-acyl amino acid, sodium alkyl naphthaleneate , Sodium N- (2-sulfo) ethyl-N-methylalkanamide, 2-sulfosuccinic acid dialkylamide.

Strongly basic amine: morpholine, piperidine, piperazine, pyrrolidine, pyrrole, imidazole, diethylamine, benzylamine and the like.

The composition ratio of the anionic surfactant as the wettability improver and / or the strongly basic amine is 1 to 100 parts (preferably 2 parts) with respect to 100 parts of the hydrocarbon oil.
~ 80 parts). If it is less than 1 part, it is difficult to improve the wettability of the release agent to the mold, while if it exceeds 100 parts,
The effect does not increase in proportion to the amount.

When an anionic surfactant is used as the wettability improver, the total amount of the anionic surfactant and the surfactant as the dispersant is 2 to 80 parts. When a nonionic surfactant is used as the surfactant, the anion /
Non-ion = 1/9 to 9/1 (preferably 4/6 to 8 /
2).

(3) In addition to the above-mentioned essential components, it is desirable to add a higher fatty acid and a derivative thereof as a mold release auxiliary, and a small amount of water as an emulsion nucleating agent.

Examples of higher fatty acids include stearic acid having 8 to 20 carbon atoms, palmitic acid, oleic acid, and the like, and examples of the derivatives include ester / amide derivatives thereof. The compounding amount of the release aid is 2 to 40 parts with respect to 100 parts of the hydrocarbon oil.

The addition of water is a conventional method for facilitating natural emulsification, and the core of the O / W emulsion is previously formed in the release agent composition, and the emulsion when diluted with water described below is used. It becomes easy to convert. The amount of water added at this time is 1/10 of the total amount of the hydrocarbon oil and the surfactant.
~ 1/5.

B. The mold release agent stock solution of the present invention is prepared by mixing and adding the above-mentioned respective compounding agents at the same time, stirring the mixture with a mixer or the like, and storing and transporting in that state. Then, when it is applied to the mold surface, it is appropriately viscosity-adjusted with water (usually 1 to 30).
It is diluted with cP) and used as a release agent.

Since it can be diluted with water, the release agent stock solution of the present invention does not become bulky during storage and transportation, and storage and transportation becomes easy.

Further, in the composition of the release agent at the time of coating, the ratio of water to hydrocarbon oil (to 60% or more) can be relatively increased, which contributes to resource saving and improvement of fire safety.

C. The mold release agent prepared by diluting the stock mold release agent solution with water by the above method is applied to a model or the like when a green mold is formed. Applicable models are not limited to metal models (cast iron, copper alloy, aluminum alloy, steel, etc.), but may be plastic models (epoxy resin, etc.), plaster models, wooden models, and the like. The application method is usually spray application, but any method such as brush application or dip application may be used.

Further, the coating amount of the release agent is usually 2
0 to 400 ml / m ² .

Next, using the model, molding is continuously performed by various molding methods such as squeeze, jolt, blowing, and sand slinger.

[0031]

The stock solution of the mold release agent of the present invention contains a hydrocarbon-based oil as a main agent for mold release action, and in addition to the hydrocarbon-based oil, it has a surface activity as a dispersant. Agent and an anionic surfactant as a wettability improver and / or a strongly basic amine are contained as essential components, diluted with water and used in the form of an O / W emulsion. Depending on the configuration, the following actions and effects are achieved.

As shown in the examples described below, the improved wettability with respect to the mold when used as a mold release agent,
A mold (particularly a mold) after being applied with a release agent and used for molding
Even if oil remains on the surface, it will not be repelled when applied to the mold surface, and a uniform release film can be formed on the mold surface, and the release agent can be applied in the form of an O / W emulsion. .

Therefore, since the release agent stock solution of the present invention can be diluted with water, it does not become bulky during storage and transportation, and storage and transportation are facilitated.

Further, in the composition of the release agent at the time of coating, the ratio of water to hydrocarbon oil (to 60% or more) can be relatively increased, which contributes to resource saving and improvement of fire safety.

[0035]

EXAMPLES Examples carried out to confirm the present invention will be described below together with comparative examples.

A. Test Method In Examples 1 to 9 and Comparative Example 1, the mixture of the formulation shown in Table 1 was manually stirred with a glass rod in a beaker to prepare each release agent stock solution.

Then, water for dilution was added to each release agent stock solution so as to have the composition shown in Table 1 while manually stirring with a glass rod as described above to prepare a release agent.

Comparative Example 2 is a commercially available mold release agent for shell molds having the following composition.

Composition Dimethyl silicone 500 30 parts Secondary linear alcohol ethoxylate (HLB 13.5) 8 parts Sodium dodecylbenzene sulfonate (50% concentration) 1 part Water 61 parts Chromium plated cast iron Fig. 1 Each mold release agent was spray-applied from the distance of 40 cm to the inner surface of the metal model 1 having the cross section shown in (1) (coating device: Meiji Co., caliber: 0.13 mm, air pressure: 392 kPa, coating time: 1 second). (For each molding).

Immediately after that, green sand material 3 with a water content of 3.5%
Was put into the inner surface of the metal model 1, and the squeeze head 5 was used to perform squeeze molding. The molding conditions were as follows: raw sand input: 80 g, squeeze pressure: 980 kPa, molding height: about 13 mm. Then, the following items were tested.

(1) Releasing property (staining degree): After molding, the metal model was inverted and dropped vertically from a height of 10 cm to release the molding mold from the metal model 1. The degree of clinging of the raw sand to the metal model 1 at that time was visually determined. Then, the molding was repeated, and the continuous mold releasability (mold releasability after 6 times molding) was judged together with the initial mold releasability.

The evaluation criteria are as follows.

⊚: Very good, ◯: Good, Δ: Some sand grains remain, Χ: Sand grains cling.

(2) Liquid stability: After the release agent for coating was prepared, it was allowed to stand in a room for 24 hours, and the state of the liquid was visually judged.

The evaluation criteria are as follows.

⊚: The emulsion is not separated for 24 hours and the dispersion is beautiful.

◯: No separation occurs after 24 hours.

Δ: Separation occurs within 24 hours.

B. Test results and evaluation Table 2 shows the test results.

(1) In terms of releasability, each of the examples of the present invention was compared with Comparative Example 1 (without a wetting improver) and Comparative Example 2.
It can be seen that it is superior to (commercially available mold release agent for shell mold), and not only the initial mold release property but also the continuous mold release property is good.

The mold release agent of Example 1 was used to mold a mold such as a differential case in a green sand molding machine in an actual foundry, but 30 to 40 shots were found to cause molding defects such as mold dropping. I was able to mold without generating.

(2) Regarding the liquid stability, it can be seen that the example of the present invention is generally better than the comparative example 1.

[0053]

[Table 1]

* 1) Fog solvent: made by Nippon Oil Co., Ltd.

[0055]

[Table 2]

[Brief description of drawings]

FIG. 1 is a schematic view of a squeeze molding method when a releasability test or the like is performed.

[Explanation of symbols] 1 ... metal model, 3 ... green sand, 5 ... squeeze head,

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C10M 129: 68 133: 16 133: 38 135: 10 129: 50) C10N 40:36

Claims (2)

[Claims] 1. A stock solution of a release agent for green molding, which contains a hydrocarbon-based oil as a release-acting main agent, which comprises, in addition to the hydrocarbon-based oil, a surfactant as a dispersant and a wettability. An anionic surfactant and / or a strongly basic amine as an improving agent is contained as an essential component, and diluted with water to be used in the form of an oil-in-water emulsion, which is a mold-molding release material. Mold stock solution. 2. A mold-releasing agent for green molding in the form of an oil-in-water emulsion containing a hydrocarbon-based oil as a releasing agent, which comprises a surfactant as a dispersant in addition to the hydrocarbon-based oil. A release agent for biomolding, comprising an agent and an anionic surfactant as a wettability improver and / or a strongly basic amine as essential components.