JPH07106422B2 - Die-casting release agent - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to an improved mold release agent for die-casting dies.

BACKGROUND ART Conventionally, die casting release agents have been made to have heat resistance by adding fatty acids, paraffin wax, silicone oil, graphite, etc. to a base material of animal and vegetable oil or mineral oil. Even if such additives are highly heat-resistant, the addition of fatty acids or paraffin wax alone can increase the viscosity of the release agent emulsion, which can be a detrimental factor to the automatic spraying process. It is also known that the addition of silicone oil or graphite can cause product defects such as flow lines and voids due to residual solids in the die casting die, and can also cause contamination of the die.

Furthermore, there are also commercially available die casting release agents containing solid substances. However, when these types of release agents are used in a centralized piping system for automatic spraying of the release agent, they can cause nozzle clogging and other operational problems.

The release agent of the present invention does not contain additives such as silicone oil or graphite that leave solid residues on the die-casting die, but is composed solely of animal and vegetable oils, mineral oils, fatty acids and their esters as its base material. Therefore, there is no risk of contamination of the die-casting die due to silicone oil or graphite, and no risk of contamination of the working environment or pollution caused by graphite, and wastewater treatment is also easy.

However, water-soluble emulsions composed solely of these oils and fats have the drawback that the viscosity of the aqueous solution changes greatly, increasing dramatically with increasing liquid temperature, and in extreme cases gelling occurs.

DISCLOSURE OF THE INVENTION In order to achieve the above object, the release agent of the present invention is obtained by adding an alkali metal or earth metal salt of ethylenediaminetetraacetic acid (hereinafter referred to as EDTA-alkali metal or alkaline earth metal salt) to an emulsion composed of animal or vegetable oil, mineral oil, fatty acid, or its ester as a base.

It has become clear that the alkali metal or alkaline earth metal salt of EDTA prevents the formation of micelles in the aqueous emulsion of the release agent of the present invention, forms a stable emulsion, and is hardly affected by temperature. It has also become clear that, since it forms a water-soluble complex with the divalent metal ion, no precipitates are formed even when hard water is used to dilute the release agent.

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the die casting release agent according to the present invention contains an alkali metal or alkaline earth metal salt of EDTA in an amount of 10 to 100%.
By adding 0,000 ppm, it forms a die-casting release agent that forms a stable emulsion.
It has also been confirmed that the alkali metal or alkaline earth metal salt of TA does not adversely affect the effect as a die-casting release agent. In order to more specifically demonstrate the effects of the present invention, an example in the case of die-casting of an aluminum alloy will be given.

The amount of alkali metal or alkaline earth metal salt of EDTA added is 10
If the amount is less than 10,000 ppm, the effect of addition is not observed, and if the amount is more than 10,000 ppm, no improvement in the effect is observed.

An example of the present invention using EDTA-4Na, a representative example of an alkali metal or alkaline earth metal salt of EDTA, will be described below.

EXAMPLES The following formulation was obtained as the die casting release agent formulation of the present invention.

Fatty acid quaternary ammonium salt 18% Hydrocarbon 22% Polyoxyethylene alkyl ether 30% Fatty acid glycerin ester 10% Water 28% The above formulation was diluted three times and 300 ppm of EDTA-4Na was added. The viscosity change was measured and compared with that of an unadded sample.

The values are shown in Table 1.

The above formulation was diluted 2.5 times and the amount of EDTA-4Na added was varied to measure the change in viscosity. The results are shown in Table 2.

The above mixture was diluted 3 times and 300 ppm of EDTA-4Na was added to prepare a test sample, which was diluted 80 times before use and injection molded into aluminum alloy (JIS: ADC-12).

Machine used: 350t die-casting machine Material: ADC-12 Melt temperature: 680℃ Product: Automotive transmission oil seal As described above, the present invention provides a die casting release agent emulsion with excellent stability, and since it is composed of substances that leave little residue on the die casting mold, it also has excellent workability and produces products with stable quality.

Similar results were also obtained when other alkali metal or alkaline earth metal salts of EDTA were added.

Furthermore, by changing the type of animal or vegetable oil used, it is possible to adjust the amount of residual carbon in the die-casting release agent, which has the advantage of being able to flexibly adapt to the size of the die-casting machine.

Industrial Applicability The release agent of the present invention has been described above in relation to die casting of aluminum alloys, but the same effects can also be achieved when used as a release agent for die casting dies for aluminum, magnesium or its alloys, or zinc or its alloys.

Claims (2)

[Claims] [Claim 1] A die-casting release agent characterized by comprising an emulsion based on animal and vegetable oils and fats, mineral oil, fatty acids and their esters to which 10 to 10,000 ppm of an alkali metal or alkaline earth metal salt of EDTA has been added. 2. The die-casting release agent according to claim 1, wherein the metal to be die-cast is aluminum or its alloy, magnesium or its alloy, or zinc or its alloy.