Water-based release agent for preventing die-casting aluminum alloy surface from mildewing and black spots and preparation method of water-based release agent

Abstract

The invention discloses a water-based release agent for preventing mildew and black spots from being generated on the surface of a die-casting aluminum alloy and a preparation method. The water-based release agent comprises hexagonal boron nitride, a thickening agent and water. Wherein the thickening agent is one or more of a nonionic associative thickening agent, cellulose ether and derivatives thereof, a hydrophobic improved non-polyurethane thickening agent, bentonite and sodium polyacrylate. The problems that an existing release agent mostly contains an organic silicon component, residues are easily formed on the surface of aluminum alloy, and the residues can accelerate oxidation and mildew of the aluminum alloy in a humid environment are solved.

Description

Technical Field

[0001] The invention relates to the field of aluminum alloy surface protection, and in particular to a water-based mold release agent for preventing moldy black spots from forming on the surface of a die-cast aluminum alloy and a preparation method thereof. Background Art

[0002] Aluminum alloy is an active metal that is prone to oxidation in a humid environment or when exposed to corrosive substances, resulting in moldy black spots on the surface. In the production process of die-casting parts, the use of traditional release agents (such as silicone-based release agents) will cause silicone components to remain on the surface of aluminum alloys. These residues will accelerate the oxidation and mildew of aluminum alloys in a humid environment, especially after the die-casting parts are punched and cut. If they are not thoroughly cleaned or only rinsed with water, the remaining corrosive substances will further aggravate the mold, blackening and yellowing of the aluminum alloy surface.

[0003] At present, the commonly used release agents on the market are mostly silicone or oily release agents. Although they have good demoulding performance, they are easy to form residues on the surface of aluminum alloys, making subsequent surface treatment difficult and difficult to meet high cleanliness requirements. Therefore, it is of great significance to develop an environmentally friendly, efficient and water-based release agent that can prevent mold and black spots on the surface of aluminum alloys. Summary of the invention

[0004] The purpose of the present invention is to provide a water-based mold release agent and a preparation method for preventing mold and black spots from forming on the surface of die-cast aluminum alloys, thereby solving the problem that the existing mold release agents mostly contain silicone components and easily form residues on the surface of the aluminum alloys, and the residues accelerate the oxidation and mold of the aluminum alloys in a humid environment.

[0005] In order to achieve the above object, the present invention provides a water-based mold release agent for preventing moldy black spots from forming on the surface of die-cast aluminum alloy, the components of the water-based mold release agent include: hexagonal boron nitride, a thickener and water;

[0006] The thickener is one or more of a nonionic associative thickener, a cellulose ether and its derivatives, a hydrophobically modified non-polyurethane thickener, bentonite and sodium polyacrylate.

[0007] Preferably, the nonionic associative thickener is L-1087 nonionic associative thickener.

[0008] Preferably, relative to 1 kg of thickener, the amount of hexagonal boron nitride used is 2.8-3.2 kg, and the amount of water used is 90-110 kg.

[0009] The present invention also provides a method for preparing the above-mentioned water-based release agent, the preparation method comprising:

[0010] 1) Mix the thickener and water in advance, stir evenly, then add hexagonal boron nitride and stir to form a concentrated release agent;

[0011] 2) diluting the concentrated release agent to obtain the water-based release agent.

[0012] Preferably, relative to 1 kg of thickener, the amount of hexagonal boron nitride used is 2.8-3.2 kg, and the amount of water used is 90-110 kg.

[0013] Preferably, the hexagonal boron nitride is ground to a particle size of 0.5-2 μm.

[0014] Preferably, in step (2), water is used for dilution by 30-50 times.

[0015] Beneficial effects: The present invention provides an aqueous release agent and a preparation method for preventing mold and black spots from forming on the surface of die-cast aluminum alloys. The components of the aqueous release agent include: hexagonal boron nitride, a thickener and water; wherein the thickener is one or more of a non-ionic associative thickener, cellulose ether and its derivatives, a hydrophobically modified non-polyurethane thickener, bentonite and sodium polyacrylate. The water-based mold release agent provided by the present invention uses hexagonal boron nitride as a core component to replace the traditional silicone component, thereby significantly reducing the residue of the mold release agent on the surface of the aluminum alloy and reducing the influence of corrosive substances. The layered structure of the hexagonal boron nitride itself is bonded between layers by van der Waals force, has a low friction coefficient, can form a continuous lubricating film on the surface of the mold and the product, significantly reduces the demoulding resistance, and improves the demoulding efficiency. At the same time, it has high high temperature resistance, can still maintain stable lubricity and isolation effect at high temperature, and has strong chemical stability, and is not easy to react in a complex process environment; the prepared water-based mold release agent has high cleanliness and low residue characteristics, can effectively prevent the oxidation and mildew of the aluminum alloy surface in a humid environment; in the preparation process, water is used as a solvent, does not contain volatile organic compounds (VOCs), is harmless to the environment and operators, can be diluted according to actual needs when used, is easy to operate, and is suitable for large-scale production.

[0016] Other features and advantages of the present invention will be described in detail in the following detailed description. DETAILED DESCRIPTION

[0017] Example 1

[0018] 1 kg of L-1087 nonionic associative thickener and 100 kg of water were mixed and stirred evenly, and then 3 kg of hexagonal boron nitride was added. The hexagonal boron nitride was ground to 1 μm using a grinding device to prepare a concentrated release agent, which was then diluted 40 times with pure water.

[0019] Example 2

[0020] 1 kg of sodium polyacrylate thickener and 100 kg of water were mixed and stirred evenly, and then 3 kg of hexagonal boron nitride was added. The hexagonal boron nitride was ground to 0.5 μm using a grinding device to prepare a concentrated release agent, and the concentrated release agent was diluted 50 times with pure water.

[0021] Test Example 1

[0022] The concentrated release agent in Example 1 was diluted 40 times with pure water and then sprayed on the surface of the aluminum alloy die-casting mold for a die-casting test. It was observed that the die-casting had no moldy black spots on the surface in a high temperature and high humidity environment, and the cleanliness was significantly improved.

[0023] Test Example 2

[0024] The concentrated release agent in Example 2 was diluted 50 times with pure water and then sprayed on the surface of the aluminum alloy die-casting mold for a die-casting test. It was observed that the die-casting had no moldy black spots on the surface in a high temperature and high humidity environment, and the cleanliness was significantly improved.

[0025] Comparative Example

[0026] The silicon-based mold release agent in the prior art was sprayed on the surface of the aluminum alloy die-casting mold to carry out a die-casting test. It was observed that the die-casting parts had moldy black spots on the surface in a high temperature and high humidity environment under the same conditions.

[0027] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0028] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0029] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0030] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A water-based release agent for preventing mold and black spots from forming on the surface of die-cast aluminum alloy, characterized in that: The components of the water-based release agent include: hexagonal boron nitride, a thickener and water; Wherein, the thickener is one or more of nonionic associative thickener, cellulose ether and its derivatives, hydrophobic modified non-polyurethane thickener, bentonite and sodium polyacrylate.

2. The aqueous release agent according to claim 1, wherein The nonionic associative thickener is L-1087 nonionic associative thickener.

3. The aqueous release agent according to claim 2, wherein Relative to 1 kg of thickener, the amount of hexagonal boron nitride used is 2.8-3.2 kg, and the amount of water used is 90-110 kg.

4. A method for preparing a water-based release agent as claimed in any one of claims 1 to 3, characterized in that: The preparation method comprises: 1) Mix the thickener and water in advance, stir evenly, then add hexagonal boron nitride and stir to form a concentrated release agent; 2) diluting the concentrated release agent to obtain the water-based release agent.

5. The preparation method according to claim 4, wherein Relative to 1 kg of thickener, the amount of hexagonal boron nitride used is 2.8-3.2 kg, and the amount of water used is 90-110 kg.

6. The preparation method according to claim 5, wherein: The hexagonal boron nitride is ground to a particle size of 0.5-2 μm.

7. The preparation method according to claim 6, wherein: In step (2), dilute with water 30-50 times.