JPH0468062B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a mold release material for aluminum alloy die casting, and more specifically, mineral oil as a dispersion medium;
This invention relates to a mold release material made by mixing and dispersing a hydrous magnesium silicate clay mineral as a main material into a mold release material base material such as animal or vegetable oil or synthetic oil. [Prior Art and Problems] Conventionally, the die casting method has been used to manufacture various cast products including vehicle parts because it allows high-precision parts to be mass-produced continuously. When making aluminum alloy products using this die-casting method, a release agent is used to avoid direct contact between the mold cavity and the molten metal, prevent seizure, and improve the release of the die-casting from the mold. ing. This mold release material for aluminum alloy die casting has properties that do not cause the mold cavity and molten metal to seize, that the solidified product can be easily released from the mold without distortion, and that it wets the cavity surface uniformly. It is required that the deposited layer attached to the cavity surface be easily removed, and that the temperature load on the cavity be suppressed as much as possible. This mold release material for die casting is roughly divided into water-insoluble mold release materials and water-soluble mold release materials. Among these, water-insoluble mold release materials have a high risk of smoke generation and ignition, and due to the demand for safety, water-soluble mold release materials have recently been widely used. A water-soluble mold release agent has a basic composition of a mold release material such as water, mineral oil, or synthetic oil, and a surfactant such as a metal soap. Specifically, in order to impart heat resistance and extreme pressure properties, there are mold release materials made by adding silicone oil, synthetic wax, natural wax, petroleum wax, fatty acid ester, paraffin, grease, etc. to these basic compositions. However, since these mold release materials tend to cause seizure of the molten metal, products have been developed in which graphite is further added to these compositions to compensate for the lack of anti-seizure properties. However, although this composition certainly exhibits an effective anti-seizure effect, it has problems such as environmental pollution due to the addition of graphite, clogging of spray nozzles, and adhesion to and discoloration of molded products. Was. In addition, in order to prevent mold release and seizure, it is necessary to apply mold release material for each shot, and when applying it, it is necessary to wet the cavity surface uniformly, remove the deposited layer, or reduce the temperature load. Therefore, there were problems such as the need to spray high-pressure steam for each shot. Furthermore, in recent years, with the advancement of casting technology, there has been a strong demand for mold release materials for die casting that satisfy properties such as improved seizing resistance, improved product dimensional accuracy, and improved product appearance. It's reached. Therefore, the present inventors conducted intensive research to solve these conventional problems and conducted various systematic experiments, and as a result, the present invention was completed. [Object of the Invention] An object of the present invention is to provide a mold release material for aluminum alloy die casting that has excellent anti-seizure properties and excellent effects on cavity wettability and mold release properties when used as a mold release material. [Structure of the Invention] The mold release material for aluminum alloy die casting of the present invention is a mold release material comprising a mold release material base material made of one or more of mineral oil, animal and vegetable oil, and synthetic oil, and a hydrous magnesium silicate clay mineral. The content of the magnesium silicate clay mineral is 0.1 to 5.0% by weight (wt%) of the entire mold release material. Hereinafter, the configuration of the present invention will be explained in more detail. The mold release material base material in the present invention is one or more of volatile mineral oils, animal and vegetable oils, and high-boiling point synthetic oils, and other known materials conventionally used as mold release material base materials can be used. In addition, hydrated sodium silicate clay minerals (hereinafter referred to as
The clay mineral (hereinafter referred to as "clay mineral") is a clay mineral whose main component is hydrated magnesium silicate and has highly reactive hydroxyl groups on its surface. In addition, the clay mineral is composed of fibers with a diameter of about 0.005 to 0.6 μm, and there are pores (channels) parallel to the fibers with a rectangular cross section of about 10 x 6 Å, and the clay mineral itself is adsorbed. have the property of Incidentally, in the clay mineral, a part of magnesium may be replaced with iron, sodium, aluminum, nickel, or the like. Specifically, Sepiolite, Xylotile, Loughlinite, which mainly consists of hydrated magnesium silicate,
There are falcondoite, palygorskite whose main component is hydrated aluminum silicate, etc., and one or a mixture of two or more of these is used. Moreover, those calcined at 350°C to 1100°C may also be used. It is also commonly known as Mountain Cork.
cork), Mountain wood,
Minerals called mountain leather, meerschaum, etc. fall under this category. The clay mineral may be used in the form of powder, granules, or plates, but it is preferable to crush it to the extent that the pores of the clay mineral remain, and the size is
It is preferably within the range of 0.1 to 200 μm. More preferably, the diameter is 10 μm or less. The pulverization at this time is carried out by wet pulverization or dry pulverization using a mixer, ball mill, vibrating mill, pin mill, beater, or the like. The mold release material for aluminum alloy die casting of the present invention is prepared by mixing and dispersing the clay mineral in a mold release material base material such as mineral oil, animal and vegetable oil, or synthetic oil as a dispersion medium, and then adding appropriate additives and water as necessary. Obtained by adding and mixing. Here, the content of the clay mineral in the mold release material for aluminum alloy die casting is 0.1 to 5.0 wt% of the entire mold release material (including additives, dilution water, etc.). This indicates that when the amount added is less than 0.1wt%, the wettability,
This is because the effects such as mold releasability and anti-seizure properties cannot be sufficiently improved, and if the amount exceeds 5.0 wt%, the viscosity of the mold release material is too high, resulting in poor workability. Among these, it is particularly preferable that the amount added is 1.0 to 3.0 wt%, since the effects of the present invention can be further exhibited. In addition, as additives, silicone oil, synthetic wax, natural wax, petroleum wax, anti-seizure additives such as fatty acid ester, binding of carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), dextrin, casein, vinyl complex acid, etc. agents, surfactants, antioxidants, solid lubricants such as graphite and aluminum powder, reaction inhibitors, air-drying accelerators, fluidity improvers, etc. Here, the manufacturing method of the mold release material for aluminum alloy die casting of the present invention will be briefly described as follows. First, the clay mineral of a predetermined size and shape is sufficiently dispersed and mixed with a release material base material such as mineral oil, animal or vegetable oil, or synthetic oil, and then anti-seizing additives and bonding are added to this as necessary. Additives such as lubricants, surfactants, solid lubricants, and water are added as appropriate and uniformly dispersed and mixed to obtain a mold release material for aluminum alloy die casting. In addition, when mixing the clay mineral and the mold release material base material, first, the clay mineral and water are dispersed and mixed to form the clay mineral dispersion liquid, and then the mold release material base material is added to the dispersion liquid. Additives may be added as appropriate. Further, the additive may be included in the release material base material in advance, or may be added at the same time as the clay mineral is mixed. In addition, when mixing,
Use a household mixer, homomixer, Henschel mixer, ball mill, vibration mill, etc. Further, the mold release material according to the present invention can be used as it is without dilution, but it can be further diluted to an appropriate ratio if necessary. [Effects of the Invention] The mold release material for aluminum alloy die casting of the present invention exhibits an excellent anti-seizure effect. In addition, the mold release material of the present invention also has cavity wettability,
Demonstrates excellent mold release properties. As described above, the mechanism by which the release material for aluminum alloy die casting of the present invention exhibits this effect is not necessarily clear yet, but it is thought to be as follows. That is, the clay mineral that is the dispersoid of the mold release material used in the present invention has heat resistance, the fibers are finely loosened in the mold release material, are uniformly dispersed, and do not easily settle.
The mold release material has a stable composition. When this mold release material is applied to a mold that has been preheated to 150 to 200°C, the volatile components in the mold release material evaporate and scatter, and the clay mineral as the main material and solid lubricant added as appropriate are added. A dense film is formed in which the ingredients are finely and evenly dispersed on the inner surface of the mold. Next, when the molten metal is injected, the clay mineral loses crystallization water at 550 to 800°C and becomes semi-ceramic, forming a dense ceramic coating without changing the shape of the clay mineral, and the coating peels off from the mold. It always intervenes between the product and the inner surface of the mold and prevents contact between the two.
After solidification of the molten metal, it is thought that the product can be easily taken out due to the lubricating action of the coating. [Example] Example 1 First, 10 g of sepiolite powder having a particle size of 200 μm or less was added to water 1 and uniformly dispersed and mixed using a homomixer to obtain a sepiolite suspension. Next, a commercially available mold release material A (main components: mineral oil, wax, and metal soap) is added to the liquid, and the mixture is stirred and mixed to obtain a mold release material according to the present invention (sample number 1; mold release material base material: sepiolite: Weight ratio of water = 1:1.3:
130). After spray coating the cavity surface of the obtained die-casting mold, molten aluminum alloy (ACD12) was poured and solidified to form an 80×30×
When a 5 mm rectangular aluminum alloy product was manufactured, the extrusion force during mold release was as low as commercially available mold release material A.
(diluted 130 times with water) was approximately 0.5 times as large.
Furthermore, when commercially available mold release material A was used, seizure to the mold was observed after three shots were formed with one application, but with the mold release material of the present invention, five shots were molded with one application. However, no seizure was observed on the cavity surface, and a good product was obtained. Example 2 Commercially available mold release material A (main components: mineral oil, wax, and metal soap) was diluted 130 times with water, and diluted with water.
Sepiolite having a particle size of 0.5 to 200 μm was added in the amount shown in Table 1, mixed and dispersed to obtain mold release materials according to the present invention (sample numbers 2 to 5). The obtained mold release material was dropped onto iron plate soil heated to 160 to 220°C to conduct a wettability test. The results obtained are shown in the table. In the table, "〇" means "good wettability",
"X" indicates "poor wettability". For comparison, a wetting test was similarly conducted using the above-mentioned mold release material A. The results are also shown in the table (sample number C1).

[Table] In this wettability test, the comparative mold release material was
When it was dropped onto an iron plate at ℃, the release material did not come into contact with the iron plate and formed into a ball, but when the release material of the present invention was used, the wettability temperature increased as the amount of sepiolite added increased. , sample number 5
In the case of , it was found that even at a temperature of 220℃, it did not form into beads and could be wetted well with the iron plate. In addition, conventionally used mold release materials, including the comparative mold release material of sample number C1, have poor drainage treatment.
Although a bad odor was also generated, when the above-mentioned sample numbers 2 to 5 of the mold release materials according to the present invention were used, the effect of improving these problems was also confirmed. Example 3 After applying the mold release material of sample number 3 obtained in Example 2 to a round bar (made of SKD61), immersing it in hot water at 60°C and rubbing it with a cloth, the mold release material applied to the round bar was removed. could be easily removed. Further, for comparison, a similar test was conducted using sample number C1 as a mold release material, and this comparative mold release material was firmly attached and could not be easily removed. Example 4 Mold release material B containing ester oil, paraffin wax, and surfactant as main components was mixed with water to 130%
The mixture was diluted twice, and 1.0% by weight of attapulgite having a particle size of 200 μm was added thereto, mixed and dispersed to obtain a mold release material (sample number 6) according to the present invention. The mold release material was left at room temperature for one week, but no change occurred. For comparison, when mold release material B was left at room temperature, a yellow oil component was separated on the upper surface. As described above, the reason why the mold release material according to the present invention did not separate is considered to be because the attapulgite particles in the mold release material capture the oil component in a covering manner. Example 5 After heating a steel bar material (φ15) at 170° C., the material was immersed in the mold release material of sample number 4 obtained in Example 2, and the mold release material was applied to the surface of the material. This was immersed in molten aluminum alloy (ACD12) for 2 seconds and pulled out, but the molten metal did not adhere to the material at all and no discoloration of the material was observed. For comparison, a comparative mold release material (sample number C1) was applied to the same steel bar material in the same manner as above, and when the material was immersed in molten aluminum alloy and pulled out, molten metal remained on the surface of the material. It hardened and stuck. In addition, the immersed parts to which the molten metal had not adhered were discolored to blue-black and an oxide film was formed.

Claims (1)

[Scope of Claims] 1. A mold release material comprising a mold release material base comprising one or more of mineral oil, animal and vegetable oil, and synthetic oil, and a hydrous magnesium silicate clay mineral, wherein the blending amount of the hydrous magnesium silicate clay mineral is A mold release material for aluminum alloy die casting, characterized in that the amount is 0.1 to 5.0% by weight of the entire mold release material. 2 Hydrous magnesium silicate clay minerals include sepiolite, attapulgite, palygorskite,
The mold release material for aluminum alloy die casting according to claim 1, which is roughinite.