CN111979032B - Water-based aluminum die-casting release agent and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of release agents, and particularly relates to a water-based aluminum die-casting release agent and a preparation method thereof. The raw materials of the water-based aluminum die-casting release agent comprise 35-45% of long-chain alkyl organic silicone oil, 5-8% of fully synthetic olefin oil, 2-3% of antirust agent, composite surfactant and the balance of water in percentage by weight; the composite surfactant consists of 4-5% of nonionic surfactant and 0.2-0.5% of anionic surfactant. The release agent is mainly used in the die-casting industry.

Description

Water-based aluminum die-casting release agent and preparation method thereof

Technical Field

The invention relates to the technical field of release agents, and particularly relates to a water-based aluminum die-casting release agent and a preparation method thereof.

Background

At present, in the aluminum alloy die casting industry, the water-based aluminum alloy die casting release agent is generally compounded by using animal and vegetable oil, mineral oil, paraffin emulsion and organic silicon emulsion. Animal and vegetable oil, mineral oil and paraffin have the defects of poor high temperature resistance, easy deterioration and high impurity content due to the limitation of chemical properties. Because the aluminum alloy die casting is a production process of injecting molten aluminum liquid and then cooling and die casting for molding, the high temperature generated in a short time can cause the high temperature decomposition and carbonization of animal and vegetable oil, mineral oil and paraffin in the formula, thereby not only reducing the service performance of the product, but also increasing the consumption of the release agent. Meanwhile, the carbonized residue impurities can be accumulated on the surfaces of the die and the part, the maintenance period of the die is shortened, the complexity and the processing difficulty of the subsequent finish machining of the part are increased, the rejection rate is increased, and some low-end organic silicon emulsions used in the formula can influence the subsequent paint spraying processing, so that the paint adhesion force does not reach the standard and the paint is easy to fall off.

Therefore, there is a need to develop an improved aqueous mold release agent for aluminum die casting, which addresses the problems currently existing

Disclosure of Invention

The invention aims to provide a water-based aluminum die-casting release agent and a preparation method thereof, overcomes the defects of raw material selection and practical application of the traditional release agent formula, and provides a new product which meets the requirements of modern production process and application under the trend of mechanical automatic production.

The long-chain alkyl organic silicone oil and the fully-synthesized olefin oil are used in accordance with the material, so that the cracking resistance temperature of the final product reaches 350 ℃, and the demolding efficiency at the mold closing temperature is effectively guaranteed.

The technical scheme adopted by the invention for solving the technical problems is as follows: the water-based aluminum die-casting release agent comprises, by weight, 35-45% of long-chain alkyl organic silicone oil, 5-8% of fully synthetic olefin oil, 2-3% of an antirust agent, a composite surfactant and the balance of water; the composite surfactant consists of 4-5% of nonionic surfactant and 0.2-0.5% of anionic surfactant.

The composition of the aqueous aluminum die-casting release agent emulsion provided by the invention uses the modified long-chain alkyl organic silicone oil, and the silicone oil keeps the high temperature resistance and the release force of the silicone oil, enhances the compatibility with paint components, and has excellent subsequent coating performance. The invention optimizes and proportionally combines various materials in the formula, particularly uses fully synthetic olefin oil to replace animal and vegetable oil and mineral oil, uses paraffin emulsion, plays a role in complementing the performance of long-chain alkyl organic silicone oil, reduces the loss of the coating at high temperature, reduces the spraying amount of a mold surface release agent in the production process, and reduces the using amount of a single-mode coating on the premise of ensuring the qualification rate of parts and products, thereby reducing the production cost of users. Meanwhile, the invention finally selects the scheme of emulsifying the mixture of the long-chain alkyl organic silicone oil and the fully synthetic olefin oil once to obtain the final product, improves the production efficiency and solves the low efficiency problem of classifying, emulsifying and mixing the raw materials.

The invention uses the fully synthetic olefin oil to replace animal and vegetable oil, mineral oil and wax raw materials in the traditional formula, and firstly solves the problems of too fast accumulation of residues on the surface of the die at high temperature and too short maintenance period. The application of the fully-synthesized olefin oil in the formula at least prolongs the maintenance period by one time, reduces the disassembly frequency of mold maintenance, maintains the continuity of automatic production, and reduces the problems of energy waste and low efficiency caused by repeated shutdown. On the other hand, the automatic die casting machine is provided with an automatic spraying device, wax materials used in the traditional formula are solidified and accumulated at normal temperature, the nozzle of a spray head is easy to block, and frequent cleaning is needed.

The composite application of the long-chain alkyl organic silicone oil and the fully-synthesized olefin oil has wider applicability, well meets the general requirements of automatic continuous on-line centralized proportioning and centralized liquid supply of large and small tonnage machines, improves the surface smoothness of finished parts, reduces the burden of mechanical finish machining, and reduces the working hour of finish machining.

In all aspects, the invention can effectively improve the production efficiency and the production quality and better control the comprehensive production cost.

Preferably, the nonionic surfactant is 1.5-2% AEO-15 and 2.8-3.5% AEO-3.

Preferably, the anionic surfactant is sodium tripolyphosphate.

Preferably, the raw materials of the antirust agent are 1-1.5% of sebacic acid and 1-1.5% of diethanolamine.

Preferably, the water-based aluminum die casting release agent also comprises 0.01-0.02% of bronopol.

Preferably, the average particle diameter of the emulsion formed by each component of the water-based aluminum die casting release agent is 50-100 nm.

Preferably, the long-chain alkyl silicone oil has an alkyl carbon chain number of 12 and a viscosity of 1200mm2/s (25 ℃).

Preferably, the fully synthetic olefin oil has a viscosity of 2700-.

The performance parameters of the long-chain alkyl organic silicone oil and the fully-synthesized olefin oil play a very important role in the performance of the product. The inventors have found through long-term studies that the properties of the product obtained by using the above-mentioned performance parameters can meet the expected effects.

Preferably, the aqueous aluminum die casting mold release agent is a milky white liquid with a viscosity of 700cps and a pH of 7.7. The cracking temperature can reach 350 ℃.

The long-chain alkyl organic silicone oil and the fully synthetic olefin oil are two oily organic matters with high water repellency and are insoluble in water. The surface tension of oil phase and water phase is reduced by adding emulsifier, so that these two kinds of oily matter are uniformly dispersed in water, and the hydrophilic and lipophilic power of emulsifier is used to form emulsion under the action of external force. The aqueous aluminum die-casting release agent emulsion is one of the main application forms of the die high-temperature protection coating, has the characteristics of stable and fine performance, uniform film formation, no toxicity, no corrosion, convenient storage, convenient use and the like, is easy to dilute with water, and is convenient for use requirements under different concentrations.

The long-chain alkyl silicone oil is modified silicone with carbon chain alkyl grafted to the end of the silicone, and the fully-synthesized olefin oil is a high-viscosity polymer (the viscosity is 2700-3300mPa s) in polyolefin. The water-based emulsion prepared from the two polymers is sprayed on the surface of a mould, and a protective coating formed after drying has the characteristics of high temperature resistance, strong liquid aluminum water impact resistance, enhancement of the fluidity of liquid aluminum water in the mould and the like; meanwhile, the long-chain alkyl organic silicone oil has excellent isolation capability (demolding force) under low content, the lubricity of the fully-synthesized olefin oil reduces the stripping force of the aluminum alloy parts during demolding, and the yield of products is improved while the mold is protected, the service life of the mold and the service life of peripheral parts are prolonged.

Although ordinary silicone oil (mainly represented by methyl silicone oil and methyl phenyl silicone oil) has excellent temperature resistance and low stripping force performance. However, the symmetrical structure of the silicon (Si) as the main chain and the short carbon chain grafting has a plurality of disadvantages in the application of water-based paint, particularly when the structure is used in the field of high-pressure aluminum die-casting release agent, the water-based emulsion with long-term stability is difficult to prepare due to the high water repellency and the chemical polarity of the structure, and meanwhile, the silicone oil remained on the surface of the part also increases the difficulty of cleaning and coating the part in the subsequent process, so that the problems of low adhesion of the subsequent paint and easy paint falling are caused. The structure of the long-chain alkyl silicone oil just solves the problem, the organic matter with long carbon chains is grafted on the silicon main chain, so that the performance of the organic silicon is kept, the cleaning is convenient, the binding force with the subsequent coating is enhanced due to the existence of the long carbon chains, the paint adhesion is improved, and the paint falling phenomenon is avoided. The existence of the long-chain alkyl provides feasibility for preparing long-term stable aqueous emulsion. Based on the advantages, the invention selects the long-chain alkyl modified organic silicone oil as the main component.

Although the organic silicon has high temperature resistance and anti-blocking performance and provides excellent demolding force in a die-casting process, if the organic silicon is used alone, the use effect can be met only by using a higher using amount, and based on the cost consideration during industrial continuous production, the invention uses the fully-synthesized olefin oil to improve the formula, and achieves the purpose of performance complementation during material application through a compound scheme.

The fully synthetic olefin oil compounded in the formula is a polyolefin high-viscosity polymer, has excellent lubricity and temperature resistance, has the physical property of high-temperature thermal sublimation, reduces the residue on the surface of a mold, prolongs the maintenance period of the mold, and improves the production efficiency. The fully synthetic olefin oil is used as a formula component, so that the fluidity of molten aluminum in the die can be greatly improved, the defective rate is reduced, and the die casting machine is more suitable for a modern high-speed die casting machine. The fully synthetic olefin oil simultaneously makes up the shortage of lubricity of the organic silicone oil at low content, improves the mold stripping efficiency, improves the surface smoothness of parts and reduces the burden of subsequent finish machining.

The preparation method of the water-based aluminum die-casting release agent is characterized by comprising the following steps: the method comprises the following steps:

a. sequentially adding water, diethanolamine and sebacic acid into a No. 2 stirring kettle, and stirring for 1 hour to obtain a water-based antirust agent, namely a material A;

b. sequentially adding water and sodium tripolyphosphate into a 3# stirring kettle, and stirring for 1 hour to obtain an aqueous solution of an anionic surfactant sodium tripolyphosphate, namely a material B;

c. in a No. 1 stirring kettle, two independent stirrers of a stirrer A and a stirrer B are arranged, wherein the stirrer A is provided with a basket-type stirring head, and the stirrer B is provided with a high-speed homogenizing stirring head;

firstly, long-chain alkyl organic silicone oil and fully-synthesized olefin oil are put into a No. 1 stirring kettle, a stirrer A is started, after stirring for 30 minutes, surfactants AEO-15 and AEO-3 are added, stirring is carried out for 30 minutes, then a material B and a material A are sequentially added, and then water is added in batches;

d. starting the stirrer B while keeping the stirrer A running, stirring for 30 minutes, and adding the rest water;

e. adding the bronopol into a No. 1 stirring kettle, and continuously stirring for 10-15 minutes to obtain a final product.

The invention has the beneficial effects that:

(1) the scheme aims to solve the problem of primary emulsification of a mixture of long-chain alkyl organic silicone oil and fully-synthetic olefin oil, improves the proportion of raw materials, and meets the requirement of emulsification by adopting the compound application of nonionic fatty alcohol-polyoxyethylene ether AEO-3 and AEO-15 and an anionic surfactant sodium tripolyphosphate.

(2) Meanwhile, the protection of the die is considered, the service life of the die is prolonged, and the rust-proof material of a sebacic acid system is added in the formula, so that the corrosion of the water-based product to the die is reduced, and the protection effect is provided.

(3) The 3 kinds of nonionic surfactants are compounded and applied, and the formula and the production process are optimized, the mixture of long-chain alkyl organic silicone oil and fully-synthesized olefin oil is used as an emulsified substance, the compound is used as an emulsifier, the finally generated water emulsion is an oil-in-water system, and the reasonable production process is matched, so that the water-based aluminum die-casting release agent emulsion with the particle size of 50-100nm can be finally obtained.

Detailed Description

The technical solution of the present invention will be further specifically described below by way of specific examples.

In the present invention, the raw materials and equipment used are commercially available or commonly used in the art, unless otherwise specified. The methods in the following examples are conventional in the art unless otherwise specified.

The water-based aluminum die-casting release agent comprises, by weight, 35-45% of long-chain alkyl organic silicone oil, 5-8% of fully synthetic olefin oil, 2-3% of antirust agent, composite surfactant, 0.01-0.02% of bronopol and the balance of water; the composite surfactant consists of 4-5% of nonionic surfactant and 0.2-0.5% of anionic surfactant. The nonionic surfactant is 1.5-2% of AEO-15 and 2.8-3.5% of AEO-3. The anionic surfactant is sodium tripolyphosphate. The raw materials of the antirust agent are 1-1.5% of sebacic acid and 1-1.5% of diethanolamine.

The average particle diameter of the emulsion formed by the components of the water-based aluminum die casting release agent is 50-100 nm.

Example (b):

for the smooth going on of guarantee emulsification process and the quality of final product, main stirred tank (1# stirred tank) in this scheme production has been equipped with A, two independent mixers of B, wherein the A mixer is equipped with basket formula stirring head, its main function is the problem of solving the oily material of high viscosity and gluing the wall and gluing the end easily, make the material can get into emulsification process system completely, avoid final product to contain the oil phase material that is not emulsified and influence the finished product quality, simultaneously, the water conservancy diversion effect of its reverse stirring, the mobility and the degree of consistency of liquid in the ability increase stirred tank. The B stirrer is provided with a high-speed homogenizing stirring head which has excellent homogenizing and emulsifying capacity and ensures the dispersion stability of the final product.

The preparation method comprises the following steps:

a. and (3) sequentially adding water, diethanol amine and sebacic acid into a No. 2 stirring kettle, and stirring for 1 hour to obtain the water-based antirust agent serving as the material A.

b. And (3) sequentially adding water and sodium tripolyphosphate into a No. 3 stirring kettle, and stirring for 1 hour to obtain an aqueous solution of an anionic surfactant sodium tripolyphosphate, namely a material B.

c. Firstly adding long-chain alkyl organic silicone oil and fully-synthesized olefin oil into a No. 1 stirring kettle, starting a stirrer A, stirring for 30 minutes, then adding surfactants AEO-15 and AEO-3, stirring for 30 minutes, then sequentially adding a material B and a material A, and then adding water in batches.

d. While keeping the mixer A running, the mixer B was started and stirred for 30 minutes, and then the remaining water was added.

e. Adding the bronopol into a No. 1 stirring kettle, and continuously stirring for 10-15 minutes to obtain a final product.

According to the scheme, a mixture of long-chain alkyl organic silicone oil and fully-synthetic olefin oil is used as an emulsified substance, fatty alcohol-polyoxyethylene ether (AEO-15), fatty alcohol-polyoxyethylene ether (AEO-3) and sodium tripolyphosphate are used as emulsifiers, and a water-based antirust agent is added into a formula by virtue of special emulsification equipment, so that the water-based aluminum die-casting release agent emulsion of a water-shaped oil-in-oil system is finally prepared.

The bronopol is added as a preservative, so that the corrosion of the microbial bacteria to the product is reduced, and the long-term storage of the final product is ensured.

Specifically, the actual production process based on 1000Kg finished product discharge is as follows:

a. and (2) sequentially adding 26Kg of water, 14Kg of diethanolamine and 12.5Kg of sebacic acid into a No. 2 stirring kettle, and stirring for 1 hour to obtain the aqueous antirust agent, namely the material A.

b. And (3) sequentially adding 16Kg of water and 4Kg of sodium tripolyphosphate into a No. 3 stirring kettle, and stirring for 1 hour to obtain an aqueous solution of an anionic surfactant sodium tripolyphosphate, namely a material B.

c. In a No. 1 stirring kettle, firstly adding 400Kg of long-chain alkyl organic silicone oil and 60Kg of fully-synthesized olefin oil, starting a basket type stirrer A, stirring for 30 minutes, then adding 20Kg of surfactant AEO-15 and 30Kg of surfactant AEO-3, stirring for 30 minutes, then sequentially adding material B and material A, and then adding 7.4Kg of water.

d. While the stirrer A was kept in operation, the homomixer B was started, and after stirring for 30 minutes, the remaining 410kg of water was added and stirring was kept for 1 hour.

e. Adding 0.1Kg of bronopol into the No. 1 stirring kettle, and continuously stirring for 10-15 minutes to obtain the final product.

The water-based aluminum die-casting release agent emulsion with the particle size of 50-100nm is finally obtained by matching the formula, reasonable process production conditions and professional production equipment.

The specific dosing schedule is shown in the table below.

The material A consists of materials with the serial numbers 1,2 and 3.

Serial number	Name of raw materials	Ratio of	Quantity of feed (Kg)
				1	Sebacic acid	1.25％	12.5
2	Diethanolamine (DEA)	1.4％	14
				3	Water (W)	2.6％	26

Material B consisted of numbers 5, 6.

Serial number	Name of the raw materials	Ratio of	Quantity of feed (Kg)
				5	Sodium tripolyphosphate	0.4％	4
6	Water (W)	1.6％	16

And (3) other materials.

Serial number	Name of the raw materials	Ratio of	Quantity of feed (Kg)
				7	Long-chain alkyl organic silicone oil	40％	400
8	Fully synthetic olefin oil	6％	60
				9	AEO-15	2％	20
10	AEO-3	3％	30
				11	Water (W)	41.74％	417.4
12	Bronopol	0.01％	0.1
				Total up to		100％	1000

Performance characterization the product prepared by the above method was a milky white liquid with a viscosity of 700cps and a pH of 7.7. When in use, the water-soluble emulsion can be diluted with water in any proportion.

And (3) stability testing: the prepared product has no precipitate and no layering after 12 months of standing.

Through tests, the heat-resistant temperature of the product is more than 350 ℃, the upper limit temperature is about 420 ℃, and the performance is sharply reduced after the temperature is more than 420 ℃.

Thermal analysis of the product showed that decomposition started after more than 500 ℃.

The water-based aluminum die-casting release agent is prepared by the method, the prepared heat-resistant aluminum alloy die-casting release agent is used for die-casting of aluminum alloy, metal polishing and sand blasting are carried out on a die, after preheating treatment, the prepared die-casting release agent is diluted by water and sprayed on the surface of the preheated die, and the mass ratio of the die-casting release agent to the water is 1: 1-4. The results show that the surface of the casting after demoulding is smooth, the smoothness is high, and the casting is easy to separate from the mould.

The above-described embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention in any way, and other variations and modifications may be made without departing from the spirit of the invention as set forth in the claims.

Claims (6)

1. A water-based aluminum die casting release agent is characterized in that: the raw materials of the water-based aluminum die-casting release agent comprise 35-45% of long-chain alkyl organic silicone oil, 5-8% of fully synthetic olefin oil, 2-3% of antirust agent, composite surfactant and the balance of water in percentage by weight; the composite surfactant consists of 4-5% of nonionic surfactant and 0.2-0.5% of anionic surfactant;

the nonionic surfactant is 1.5-2% of AEO-15 and 2.8-3.5% of AEO-3;

the raw materials of the antirust agent are 1-1.5% of sebacic acid and 1-1.5% of diethanolamine;

the viscosity of the fully synthetic olefin oil at 20 ℃ is 2700-3300mPa s, the average molar mass is 4600, in the fully synthetic olefin oil, the 1,4 cis double bonds account for 77 percent, the 1,4 trans double bonds account for 22 percent, and the 1,2 vinyl double bonds account for 1 percent;

the water-based aluminum die casting release agent also comprises 0.01-0.02% of bronopol.

2. The aqueous aluminum die casting mold release agent according to claim 1, characterized in that: the anionic surfactant is sodium tripolyphosphate.

3. The aqueous aluminum die casting mold release agent according to claim 1, characterized in that: the average particle size of emulsion formed by the components of the water-based aluminum die casting release agent is 50-100 nm.

4. The aqueous aluminum die casting mold release agent according to claim 1, characterized in that: the carbon number of the alkyl carbon chain of the long-chain alkyl organic silicone oil is 12, and the viscosity of the long-chain alkyl organic silicone oil at 25 ℃ is 1200mm ² /s。

5. The aqueous aluminum die casting mold release agent according to claim 1, characterized in that: the viscosity of the aqueous aluminum die casting release agent is 700-750cps, the pH value is milky white liquid of 7.5-7.7, and the cracking resistance temperature is more than 350 ℃.

6. The process for preparing an aqueous aluminum die casting release agent according to any one of the preceding claims, characterized in that: the method comprises the following steps:

a. sequentially adding water, diethanolamine and sebacic acid into a No. 2 stirring kettle, and stirring for 1 hour to obtain a water-based antirust agent, namely a material A;

b. sequentially adding water and sodium tripolyphosphate into a No. 3 stirring kettle, and stirring for 1 hour to obtain an aqueous solution of an anionic surfactant sodium tripolyphosphate, namely a material B;

c. in a No. 1 stirring kettle, two independent stirrers of a stirrer A and a stirrer B are arranged, wherein the stirrer A is provided with a basket-type stirring head, and the stirrer B is provided with a high-speed homogenizing stirring head;

firstly, long-chain alkyl organic silicone oil and fully-synthesized olefin oil are put into a No. 1 stirring kettle, a stirrer A is started, after stirring for 30 minutes, surfactants AEO-15 and AEO-3 are added, stirring is carried out for 30 minutes, then a material B and a material A are sequentially added, and then water is added in batches;

d. starting the stirrer B while keeping the stirrer A running, stirring for 30 minutes, and adding the rest water;

e. adding the bronopol into a No. 1 stirring kettle, and continuously stirring for 10-15 minutes to obtain a final product.