A water-based release agent for aluminum alloy die casting and preparation method thereof

Abstract

The invention relates to the technical field of casting, and discloses a water-based demoulding agent for aluminum alloy die casting and a preparation method thereof, comprising: a solvent, a composite emulsion, an emulsifier, a defoaming agent, a phosphate compound, and silicone oil; the demoulding agent prepared by the invention can form a dense and smooth protective film on the surface of a mold, which is used to isolate the metal liquid and the mold in a molding process; the demoulding agent of the invention can be tightly bonded to the surface of the mold, is not easy to fall off or be damaged, and the formed protective film will not react or adhere to the metal, and can well peel off the metal casting product after molding.

Description

Technical Field

[0001] The invention relates to the technical field of casting, in particular to a water-based demoulding agent for aluminum alloy die casting and a preparation method thereof. Background Art

[0002] As a metal forming method using a die, there are a casting method and a die forging method. Examples of the casting method include a low-pressure casting method, a pressure casting method, and the like.

[0003] Mold release agent, also known as release agent, is a product designed for special molding and forming processing. It is a chemical additive used for lubrication in metal processing production. When the mold release agent is used, it will form a dense and smooth film on the mold surface.

[0004] The Chinese invention patent with application publication number CN107999692A discloses a water-based release agent for die-casting aluminum alloy, which is composed of mineral oil, lubricant, silicone oil, surfactant, preservative, wetting agent, stabilizer, thickener and water, and the mass percentage of the components is: engine oil 20-30, silicone oil 10-15, silicon dioxide 1-5, stearic acid 5-7, polyoxyethylene fatty acid ester 8-10, polyoxyethylene oleyl ether 4-6, organic molybdenum compound 0.5-1.5, beeswax 3-5, ethanol 0.5-1.5, sodium nitrite 0.5-1, triethanolamine 0.5-2, organic silicon wetting agent 0.5-2, thickener 0.5-1, sodium benzoate 0.5-2, sodium phosphate 0.5-2, sorbic acid 0.5-1, water 25-35. The stability and demoulding performance of the water-based die-casting aluminum alloy release agent of the invention need to be further improved.

[0005] Based on this, we proposed a water-based release agent for aluminum alloy die casting, hoping to solve the shortcomings of the existing technology. Summary of the invention

[0006] 1. Technical issues to be resolved

[0007] In view of the deficiencies in the prior art, the present invention provides a water-based release agent for aluminum alloy die casting.

[0008] (II) Technical solution

[0009] To achieve the above-mentioned purpose, the present invention provides the following technical solutions:

[0010] A water-based mold release agent for aluminum alloy die casting comprises, by weight, 80-90 parts of solvent, 10-20 parts of composite emulsion, 1-2 parts of emulsifier, 1-1.5 parts of defoamer, 2-5 parts of phosphate compound and 1-2 parts of silicone oil.

[0011] As a further technical solution, it comprises 12-16 parts of composite emulsion and 1.2-1.6 parts of silicone oil, wherein the weight ratio of composite emulsion to silicone oil is 10:1.

[0012] As a further technical solution, the composite emulsion preparation method is:

[0013] The raw material components are mixed together in sequence and pre-emulsified to obtain a pre-emulsified liquid;

[0014] Take 10% of the pre-emulsion by weight, add the initiator solution thereto, stir for 15 minutes, then gradually add the remaining pre-emulsion, stir and react for 2 hours, and finally adjust the pH to 7.5 with ammonia water to obtain the product.

[0015] As a further technical solution: the raw material components include hydroxyethyl methacrylate, perfluoroalkylethyl methacrylate, styrene, butyl acrylate, isobutoxymethyl-acrylamide, acrylic acid, 4-phenylene acid, sodium dodecyl diphenyl ether disulfonate and deionized water.

[0016] As a further technical solution, the silicone oil is prepared by ring-opening polymerization reaction with octamethylcyclotetrasiloxane and divinyltetramethyldisiloxane as raw materials under the action of an acid or base catalyst.

[0017] As a further technical solution, the catalyst is a hydroxide of alkali metal K or Na.

[0018] A method for preparing a water-based release agent for aluminum alloy die casting, comprising:

[0019] Mixing an emulsifier, a phosphate compound, and silicone oil together to obtain a mixture;

[0020] The composite emulsion, the solvent and the defoamer are sequentially added to the mixture and mixed evenly to obtain a water-based release agent.

[0021] (III) Beneficial effects

[0022] Compared with the prior art, the present invention provides a water-based release agent for aluminum alloy die casting, which has the following beneficial effects:

[0023] The release agent prepared by the present invention can form a dense and smooth protective film on the surface of the mold, which is used to isolate the molten metal and the mold during the molding process. The release agent of the present invention can be tightly bonded to the surface of the mold and is not easy to fall off or be damaged. The formed protective film will not react or adhere to the metal, and the metal casting product after molding can be well peeled off.

[0024] The present invention combines the prepared composite emulsion with silicone oil to orient the surface of the metal substrate and form a static lubricating film layer through adsorption, thereby reducing friction therebetween, forming an excellent demoulding effect, and further improving the surface quality of metal casting products.

[0025] The release agent prepared by the present invention has multiple characteristics such as rapid defoaming, long foam suppression time, strong demoulding property, etc. It can have good lubrication performance under high temperature conditions, thereby being beneficial to improving the quality of castings and production efficiency, and greatly reducing the friction between the castings and the molds. In this way, the direct contact between the castings and the molds can be reduced, the wear of the molds can be reduced, the life of the molds can be extended, and the surface quality of the castings can be improved. DETAILED DESCRIPTION

[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0028] A water-based mold release agent for aluminum alloy die casting comprises, by weight, 80-90 parts of solvent, 10-20 parts of composite emulsion, 1-2 parts of emulsifier, 1-1.5 parts of defoamer, 2-5 parts of phosphate compound and 1-2 parts of silicone oil.

[0029] The solvent used in the present invention is water;

[0030] The defoaming agent used is a polyether defoaming agent;

[0031] The emulsifier is the commercially available emulsifier OP-10; by using the emulsifier, the dispersed phase can be dispersed in the continuous phase in the form of droplets (micrometer level) during the emulsification process. The emulsifier reduces the interfacial tension of the components in the mixed system and forms a relatively strong film on the surface of the droplets or forms a double electric layer on the surface of the droplets due to the charge given by the emulsifier, preventing the droplets from aggregating with each other and maintaining a uniform emulsion.

[0032] The phosphate compound is selected from one or more of diisopropyl phosphate, isopropyl phosphate, dioctyl phosphonate, octyl phosphate, dibutyl phosphate, and isodecyl phosphate;

[0033] It comprises 12-16 parts of composite emulsion and 1.2-1.6 parts of silicone oil, wherein the weight ratio of the composite emulsion to the silicone oil is 10:1.

[0034] The composite emulsion preparation method is:

[0035] The raw material components are mixed together in sequence and pre-emulsified to obtain a pre-emulsified liquid;

[0036] Take 10% of the pre-emulsion by weight, add the initiator solution thereto, stir for 15 minutes, then gradually add the remaining pre-emulsion, stir and react for 2 hours, and finally adjust the pH to 7.5 with ammonia water to obtain the initiator solution; the initiator solution used is a 5% by mass ammonium persulfate solution;

[0037] The raw material components include, by weight: 10 parts of hydroxyethyl methacrylate, 5 parts of perfluoroalkylethyl methacrylate, 15 parts of styrene, 6 parts of butyl acrylate, 3 parts of isobutoxymethyl-acrylamide, acrylic acid, 2 parts of 4-phenylene acid, 4 parts of sodium dodecyl diphenyl ether disulfonate and 100 parts of deionized water.

[0038] Table 1 Composite emulsion performance indicators:

[0039]

[0040] The silicone oil is prepared by ring-opening polymerization reaction with octamethylcyclotetrasiloxane and divinyltetramethyldisiloxane as raw materials under the action of an acid or base catalyst.

[0041] The catalyst is a hydroxide of alkali metal K or Na, and potassium hydroxide is preferably used in the present invention.

[0042] The specific preparation method of silicone oil in the present invention is:

[0043] Add octamethylcyclotetrasiloxane to the reactor, introduce nitrogen into the reactor, exhaust the air in the reactor, then adjust the temperature to 80°C and keep it warm for 10 minutes, then add divinyltetramethyldisiloxane and potassium hydroxide, increase the temperature to 95°C, keep it warm for 2.5 hours, then add 2,6-dinitro-p-cresol, adjust the pressure in the reactor to -0.05MPa, the temperature to 152°C, keep it warm for 4.5 hours, then cool and filter to obtain the product.

[0044] A method for preparing a water-based release agent for aluminum alloy die casting, comprising:

[0045] According to respective weight parts, 1-2 parts of emulsifier OP-10, 2-5 parts of dioctyl phosphonate, and 1.2-1.6 parts of silicone oil are sequentially added into a stirring device, and stirred at a speed of 150 r / min for 30 min at room temperature to obtain a mixture;

[0046] 12-16 parts of composite emulsion, 80-90 parts of water and 1-1.5 parts of defoaming agent were added to the mixture in sequence, and stirring was continued at 200 r / min for 1 hour to obtain a water-based release agent; the weight ratio of the composite emulsion to the silicone oil was 10:1.

[0047] The components in the introduced composite emulsion can provide hydrophobicity and permeability, and have a strong effect on reducing surface tension. The demoulding property of the release agent itself is enhanced by introducing the prepared silicone oil.

[0048] The following are specific embodiments:

[0049] Example 1

[0050] A method for preparing a water-based release agent for aluminum alloy die casting, comprising:

[0051] According to respective weight parts, 1 part of emulsifier OP-10, 2 parts of dioctyl phosphonate phosphate, and 1.2 parts of silicone oil were sequentially added into a stirring device, and stirred at a speed of 150 r / min for 30 min at room temperature to obtain a mixture;

[0052] 12 parts of composite emulsion, 80 parts of water and 1 part of defoamer were added to the mixture in sequence, and stirring was continued at a speed of 200 r / min for 1 hour to obtain a water-based release agent; the weight ratio of the composite emulsion to the silicone oil was 10:1.

[0053] Adhesion test

[0054] Before the aluminum alloy test piece is tested, the test piece is heated in an oven at 200°C for 30 minutes and then cooled in a dryer. Before the test, the mass of the test piece is accurately measured to an accuracy of ±0.1 mg.

[0055] The aluminum alloy test piece coated with a release agent having different weight ratios of composite emulsion and silicone oil (with the composite emulsion mass unchanged) was placed in an oven at 110°C for 30 minutes, air-cooled, and cooled in a dryer for a certain period of time. The mass of the aluminum alloy test piece was measured to an accuracy of ±0.1 mg, and the adhesion amount was calculated from the difference in mass before and after the test;

[0056] Table 2

[0057] It can be seen from Table 2 that the adhesion is obviously different by using a release agent with different weight ratios of the composite emulsion and silicone oil.

[0058] Example 2

[0059] A method for preparing a water-based release agent for aluminum alloy die casting, comprising:

[0060] 1.2 parts of emulsifier OP-10, 3 parts of dioctyl phosphonate phosphate, and 1.3 parts of silicone oil were added to a stirring device in order according to respective weight parts, and stirred at a speed of 150 r / min for 30 min at room temperature to obtain a mixture;

[0061] 13 parts of composite emulsion, 82 parts of water and 1.4 parts of defoaming agent were added to the mixture in sequence, and stirring was continued at a speed of 200 r / min for 1 hour to obtain a water-based release agent; the weight ratio of the composite emulsion to the silicone oil was 10:1.

[0062] Example 3

[0063] A method for preparing a water-based release agent for aluminum alloy die casting, comprising:

[0064] 1.6 parts of emulsifier OP-10, 4 parts of dioctyl phosphonate phosphate, and 1.5 parts of silicone oil were added to a stirring device in order according to respective weight parts, and stirred at a speed of 150 r / min for 30 min at room temperature to obtain a mixture;

[0065] 15 parts of composite emulsion, 86 parts of water and 1.2 parts of defoaming agent were added to the mixture in sequence, and stirring was continued at a speed of 200 r / min for 1 hour to obtain a water-based release agent; the weight ratio of the composite emulsion to the silicone oil was 10:1.

[0066] Example 4

[0067] A method for preparing a water-based release agent for aluminum alloy die casting, comprising:

[0068] According to respective weight parts, 2 parts of emulsifier OP-10, 5 parts of dioctyl phosphonate phosphate, and 1.6 parts of silicone oil were sequentially added into a stirring device, and stirred at a speed of 150 r / min for 30 min at room temperature to obtain a mixture;

[0069] 16 parts of composite emulsion, 90 parts of water and 1.5 parts of defoaming agent were added to the mixture in sequence, and stirring was continued at a speed of 200 r / min for 1 hour to obtain a water-based release agent; the weight ratio of the composite emulsion to the silicone oil was 10:1.

[0070] Comparative Example 1:

[0071] A method for preparing a water-based release agent for aluminum alloy die casting, comprising:

[0072] According to respective weight parts, 1 part of emulsifier OP-10, 2 parts of dioctyl phosphonate phosphate, and 1.2 parts of silicone oil were sequentially added into a stirring device, and stirred at a speed of 150 r / min for 30 min at room temperature to obtain a mixture;

[0073] Add 12 parts of polyacrylic acid emulsion, 80 parts of water, and 1 part of defoamer to the mixture in sequence, and continue to stir at a speed of 200 r / min for 1 hour to obtain a water-based release agent. The solid content of the polyacrylic acid emulsion is 32.6%.

[0074] Test:

[0075] Perform demoulding performance detection on the samples of the examples and comparative examples. The detection method is as follows: Dilute the die-casting release agents of the examples and comparative examples with deionized water at a ratio of 1:150, evenly spray the diluted solution on the polished steel plate heated to 280 °C, and insert the part of the steel plate sprayed with the release agent into the molten 7075 aluminum alloy melt within 5 seconds, and take it out after 15 seconds.

[0076] Evaluation criteria for the performance of the release agent: Use the change in the mass of the steel plate after impregnation to distinguish the demoulding performance by grade. The better the demoulding performance, the less the mass increases after impregnation, and vice versa. The mass of the steel plate before impregnation is m1, and the mass increases to m2 after impregnation. Then the percentage increase in the mass of the steel plate before and after impregnation is W = (m2 - m1) / m1 × 100%. When W ≤ 0.1%, the performance is excellent; when 0.1% < W ≤ 0.5%, the performance is good; when W ≥ 0.5%, the performance is poor;

[0077] Table 3

[0078] As can be seen from Table 3, the release agent prepared by using the present invention has excellent demoulding performance.

[0079] Stability test

[0080] Storage stability: Let the prepared release agent stand at room temperature for 30 d, and observe whether there is a layering phenomenon.

[0081] Shear stability: Dilute the prepared release agent 145 times and use a high-speed stirrer to stir at 3200 rpm / min for 15 min:

[0082] Table 4

[0083] As can be seen from Table 3, by introducing the prepared composite emulsion, the present invention can improve the storage stability and shear stability of the release agent.

[0084] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the equivalents of the appended claims.

Claims

1. A water-based release agent for aluminum alloy die casting, characterized in that: The invention comprises, by weight, 80-90 parts of solvent, 12-16 parts of composite emulsion, 1-2 parts of emulsifier OP-10, 1-1.5 parts of polyether defoamer, 2-5 parts of diisopropyl phosphate, and 1.2-1.6 parts of silicone oil; wherein the weight ratio of the composite emulsion to the silicone oil is 10:

1. The composite emulsion preparation method comprises: mixing the raw material components together in sequence, performing pre-emulsification treatment, and obtaining a pre-emulsified liquid; taking 10% of the mass of the pre-emulsified liquid, adding an initiator solution thereto, stirring for 15 minutes, and then Then gradually add the remaining pre-emulsion, stir and react for 2 hours, and finally use ammonia water to adjust the pH to 7.5 to obtain; the raw material components include hydroxyethyl methacrylate, perfluoroalkylethyl methacrylate, styrene, butyl acrylate, isobutoxymethyl-acrylamide, acrylic acid, 4-phenylene acid, sodium dodecyl diphenyl ether disulfonate and deionized water; the silicone oil is prepared by ring-opening polymerization reaction with octamethylcyclotetrasiloxane and divinyltetramethyldisiloxane as raw materials under the action of potassium hydroxide as a catalyst.

2. A method for preparing a water-based release agent for aluminum alloy die casting as claimed in claim 1, characterized in that: include: The emulsifier OP-10, diisopropyl phosphate and silicone oil are mixed together to obtain a mixture; a composite emulsion, a solvent and a polyether defoamer are sequentially added to the mixture and mixed evenly to obtain a water-based release agent.

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