JPS59104243A - Mold release agent for die casting - Google Patents

Abstract

PURPOSE:To provide a mold release agent for die casting which obviates generation of defects such as sand burning, cold shut, blowhole, leakage of pressure or the like and has no problem in working environment and pollution by incorporating borate and phosphate in a specific range of >=1 kinds among Ca, Mg, Al, Fe, Ti, Si, Zr. CONSTITUTION:A mold release agent is formed by incorporating >=1 kinds among Ca, Mg, Al, Fe, Ti, Si, Zr at 0.3-0.4 times theoretical amt. so as to be incorporated in the form of borate or phosphate. For example, >=1 kinds of oxide, such as CaO, MgO, Al2O3, Fe2O3, TiO2, SiO2, ZrO2 or the like are incorporated together with boric acid or phosphoric acid in the amt. of the above- mentioned range. 1.0 Times the theoretical amt. is the case in which Ca3(BO3)2, Ca3(PO4)2, etc. are incorporated from the beginning. Cd, Hd, Pb provide similarly the ability to prevent sand burning, etc. but the problem in working environment and pollution is unavoidable.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a mold release agent for die casting, more specifically, it contains a certain range of boric acid and/or phosphoric acid inorganic salt, and does not cause problems in the working environment or pollution. The present invention relates to a heat-resistant and extreme pressure mold release agent for die casting, which can prevent or suppress seizure of metal to a mold.

In die casting for injection molding of aluminum alloys, zinc alloys, etc., a release agent is applied to the inner peripheral surface of the mold before injecting the molten metal into the mold.

Conventionally, this type of mold release agent is based on mineral oil or animal or vegetable oil, and to this base is added heat resistance and extreme pressure properties with fatty acids, wax, paraffin, grease, silicone, etc., and if necessary, pigments are added. , graphite, aluminum powder, molybdenum sulfide, etc.

However, such conventional mold release agents have, for example, 600 to 75
400~15001W of molten aluminum alloy at 0℃
In die casting under severe conditions such as injection at a pressure of /an' at 20 to 100 nV seconds, the metal is essentially extremely inferior in terms of heat resistance and extreme pressure resistance, and the injected metal adheres tightly to the mold. In addition to seizure, there are other drawbacks such as wrinkles, cavities, pressure leaks, and other defects. Furthermore, even if a mold release agent contains the above-mentioned highly heat-resistant pigment, the pigment may be washed away by the molten metal injected at high pressure and high speed, resulting in similar seizures. Another drawback is that the pigmentra may transfer to the surface of the molded article and must be cleaned in a subsequent step.

In view of the conventional drawbacks such as higher price, the inventor of the present invention has conducted intensive research into a new mold release agent for die casting, while taking into consideration the problem of working environment and pollution, and found that a certain range of boric acid They have discovered that it is sufficient to contain and/or an inorganic phosphoric acid salt, and have completed the present invention.

That is, the present invention provides a mold release agent for die casting comprising 03 to 40 times the theoretical amount of one or more selected from the following group A in the form of borate and/or phosphate. Pertains to.

Group A: Ca, Mg, AI, Fe, Ti, Si,
Zr In the present invention, one or more selected from the above-mentioned Group A is contained in such a manner that all or part thereof is in the form of borate and/or phosphate. Specifically, for example, CaOlMgO, Al2O3, FezQ3, T
One or more oxides selected from oxides such as i02.5iOz and ZrO2 are contained together with boric acid and/or phosphoric acid. And 1 selected from the above group A
The content of the species or two or more species is 0.3 to 4.0 times the theoretical amount in which they become borates and/or phosphates. A typical example where the theoretical amount is 1.0 times is Ca3(B
O3)2, Ca3(PO4)2, FeBO3, FePO
This is a case where boric acid and/or phosphoric acid inorganic salts such as No. 4 are contained.

The intended objectives of the present invention can be achieved within the scope as described above. In addition to the above-mentioned group A, for example, Cd.

If heavy metals such as Hg and Pb are included in place of Group A as described above, they will exhibit the same anti-seizure ability as Group A, but problems with the working environment and pollution cannot be avoided. ,
Undesirable. In addition, when boric acid and/or phosphoric acid is contained, as will be described later in the test example, it is not suitable for practical use, and when only group A is contained, conventional die-casting mold release agents are used. Although it may be effective when compared, it still does not fully prevent or suppress burn-in etc.
The same holds true even if the content of Group A is less than 0.3 times the theoretical amount in the form of borate and/or phosphate.

If the content exceeds 4.0 times the theoretical amount, the anti-seizure ability, etc. will be exhibited to the same degree as the present invention, but in this case, the excess group A may transfer and adhere to the molded product, or the mold may be damaged. It is inconvenient that it adheres to the inner peripheral surface.

Practically speaking, the mold release agent for die casting according to the present invention is a conventional mold release agent for die casting components such as those described above, and one or more kinds selected from the above group A, combined with borate and/or phosphoric acid. It is used, for example, by spray coating on the inner circumferential surface of a molding die, by containing 0.3 to 4.0 times the theoretical amount so that it is in the form of a salt. There is no problem in adding an alkaline component to the extent that it neutralizes the acid. The specific content of Group A, boric acid and/or 9-acid, etc. depends on the type of metal to be injected, injection conditions such as temperature, pressure, and speed, and the amount of coating (especially dilution ratio). There are no particular limitations as long as the effects of the present invention can be expressed to a desired extent.

Hereinafter, in order to make the configuration and effects of the present invention more specific,
A test example will be given regarding die casting by injecting molten aluminum alloy.

- Test Example 1 A gear case for agricultural machinery was die-cast using an aluminum alloy for die-casting (ADC-12) under the following conditions.

Machine used: 2000 ton die force machine Molten metal temperature:
Average: 720℃ Injection pressure: Crab 1,500 degrees
→ (near the gate opening) 450°C Prior to injection, the mold release agent uniformly sprayed over the entire inner surface of the mold is as follows0 Conventional example: Nijiron Form AZ 420WS (manufactured by Chubu Kagaku Kogyo Co., Ltd., containing silicone) amount) diluted 20 times with water. In relation to the Examples and Comparative Examples described later, we also tested 100-fold dilutions with water, but the seizure was significant and practical die casting was not possible.0 Examples and Comparative Examples: Table 1 or 2
A total of 10 g of the blended products shown in the table was mixed, and this was used as a stock solution.

And, in weight ratio, before this stock solution 5 Nijiron Form AZ 420W Mix at a ratio of Ski, and the mixture Diluted 100 times with water.

Table 1 Table 2 (Note: In Table 1, Example 7 was neutralized with NaOH. In Tables 1 and 2, the theoretical ratio is the total number of charges in Group A, boric acid residues and/or Or it is the value divided by the total number of charges of phosphate residues.

) The die casting results are shown in Table 3. Each side is 10
It is expressed as a defective rate (%) when 00 pieces are die-cast. However, in cases where die casting is stopped midway, the defective rate (%) up to that point is 0. Among the defective rate items, seizure, hot water wrinkles, and cavities are visually observed from the external appearance, and pressure is also measured. The leakage state was observed with the naked eye when air was pressurized at 7 kg//d to the molded product in water.

Table 3 (*1: Discontinued after 100 pieces due to significant debris accumulation.*
2: Canceled after 12 pieces due to severe burn-in. *3: Canceled after the first piece because it stuck strongly to the mold. *4: Canceled after 50 pieces due to extremely poor molded product surface. ) Test Example 2 A car cooler lid was die-cast using an aluminum alloy for die-casting (ADC-10) under the following conditions.

Machine used: 500) Die casting machine Molten metal temperature: Average 680℃ Injection pressure about 1800mm Injection speed: about 12m/sec Mold temperature during die casting: (Mold flow tip side) 200℃←
→ (near the gate opening) 350°C Prior to injection, the mold release agent was sprayed uniformly over the entire inner peripheral surface of the mold as follows.

Conventional example: Aldais ASG (manufactured by Nippon Graphite Industries, a natural graphite-containing bacterium) diluted 40 times with water. In connection with the Examples and Comparative Examples described later, we also tested samples diluted 100 times with water, but the seizure was so severe that practical die casting could not be performed.

Examples, comparative examples: Table 4 or 5 for 100g of water
The formulations shown in the table were mixed at a total of 1 og, and this was used as a stock solution.

And, in weight ratio, before this stock solution 5 At the rate of Aldais ASG'tl Mix and dilute the mixture 100 times with water. What I did.

Table 4 Table 5 (Note 2 In Table 4, Example 14 was neutralized with NaOH. In Tables 4 and 5, the theoretical ratios are the same as in Tables 1 and 2 above.

) The die casting results are shown in Table 6. The measurement of the defective rate (%), etc. is the same as in Table 3. However, only the pressure leakage was observed visually when hydrogen gas was pressurized to the molded product in water at 30 h9/Cfn'.

Table 6 (*5: Debris deposited. *6: Molded product surface defect. *7: Canceled after the first piece due to strong adhesion to the mold. *8: 100% due to markedly defective molded product surface. (1) From the results in Tables 3 and 6, it is clear that the mold release agent according to the present invention (
Example) compared to the conventional example and comparative example, there is less seizure, hot water wrinkles,
It can be seen that it is clearly superior in the effect of preventing or suppressing defects such as cavities and pressure leaks.

Patent applicant Yutaka Senishi Agent: Hiromasa Yama

Claims (1)

[Scope of Claims] 1. A theoretical amount of 03 to 03 to form one or more borates and/or phosphates selected from the following group A:
A mold release agent for die casting characterized by containing 40 times as much. Group A: CaXMg, Al, Fe, Ti,
Si, Zr