Surface coating of EPS (Expandable Polystyrene) foam mold, preparation method of surface coating and application of surface coating in reinforced EPS foam mold

Abstract

The invention discloses a surface coating of an EPS foam mold, a preparation method and application of the surface coating in reinforcing the EPS foam mold, the surface coating is prepared from the following raw materials in parts by mass: aggregate, a binder, a dispersing agent, an emulsifying agent, a curing agent, other auxiliary materials and water, and the preparation method comprises the following steps: (1) diluting the binder with water; and (2) adding aggregate, a dispersing agent, an emulsifying agent, a curing agent and other auxiliary materials into the adhesive solution diluted in the step (1), and uniformly stirring to obtain the surface coating for the EPS foam mold. The EPS foam mold with the surface coating has the characteristics of high surface smoothness, good dimensional precision, high surface strength and the like, and the reuse rate of the EPS foam mold is greatly improved. And drawing can be balanced, stress points can be enhanced, the overall strength of the mold is improved, and the problems that an EPS foam mold is prone to deformation and drawing is difficult during drawing are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of mold preparation, and in particular relates to a surface coating of an EPS foam mold, a preparation method and application thereof in enhancing the EPS foam mold. Background Art

[0002] As a basic and mainstream process in the field of casting production, sand casting is of great importance. With its strong flexibility and wide applicability, it occupies a pivotal position in the manufacturing industry. One of the core links of sand casting is the use of molds. As a key tool for shaping the shape of castings, the choice of mold material is directly related to the quality and production efficiency of castings.

[0003] At present, the mold materials used for sand casting production are diverse. Among them, wood materials have become the mainstream choice for mold manufacturing due to their good processing performance and relatively low cost. Wooden molds are easy to carve and shape, can meet the needs of different casting shapes, and their stability and durability have been widely recognized during long-term use. However, wooden molds also have certain limitations, such as being easily affected by humid environments, resulting in dimensional changes and other problems.

[0004] In addition to wood materials, metal molds (such as aluminum alloy, cast iron, cast steel, etc.) are also commonly used mold materials in sand casting. Metal molds play an important role in casting production with their high strength, high precision and long life. Castings produced using metal molds have a smooth surface and are easy to process later, greatly improving production efficiency and product quality. At the same time, metal molds can protect the mold and cavity from damage during demolding, extending the service life of the mold. However, metal molds have a long production cycle, high initial investment costs, and a relatively limited scope of application. For some castings with complex shapes, the processing difficulty and cost of metal molds will increase significantly.

[0005] In addition, some organic or inorganic non-metallic materials are also used in the production of sand casting molds, such as resins and foams. These materials have the advantages of light weight, easy processing, and low cost, and are particularly suitable for some occasions where the mold strength requirements are not high. Among them, EPS foam molds have been widely used in the production of some small batches and multiple varieties of castings due to their short manufacturing cycle and low cost. However, the surface finish of EPS foam molds is low, and the mold and cavity are easily damaged during demolding. It is a disposable mold, which limits its application range to a certain extent.

[0006] With the continuous development of science and technology, 3D printing technology has gradually been promoted and applied in the field of mold making. New materials such as high-strength plastics and resin materials have begun to be used in the production of 3D printing molds. These materials have the advantages of high precision, high strength, and strong customizability, bringing new possibilities for mold making. However, the production cost of 3D printing technology is still relatively high, and for small batches of multi-variety castings, the cost of mold making is still relatively high, and the production cycle is relatively long. Therefore, at this stage, 3D printing molds are mainly suitable for the production of some high value-added and complex-shaped castings.

[0007] In the process of continuous exploration of new mold materials, the idea of ​​replacing traditional mold materials with EPS foam has begun to be tried in production practice. EPS foam molds are easy to process and the mold production cycle is greatly shortened, which is of great significance to some companies that urgently need to respond to market changes quickly. However, there are also some obvious problems with simple EPS foam molds. Due to its rough surface and low strength, the mold is easy to deform and difficult to demold during the actual production process. In addition, EPS foam molds can only be used once, which also increases production costs and waste disposal pressure. Therefore, in the application process of EPS foam molds, it is necessary to comprehensively consider its advantages and disadvantages and reasonably select application scenarios and usage methods. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a surface coating for an EPS foam mold, a preparation method and its application in enhancing the EPS foam mold. The surface coating is applied to the surface of the EPS foam mold for compounding, which can make up for the problems of difficulty in demolding and easy deformation of the mold when the foam mold is used alone. It can balance the demolding and strengthen the stress points, improve the overall strength of the mold, and also improve the surface accuracy and smoothness of the EPS foam.

[0009] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0010] A surface coating for an EPS foam mold comprises the following raw materials in parts by mass: 22-27 parts of aggregate, 63-72 parts of a binder, 1.2-1.5 parts of a dispersant, 4-8 parts of an emulsifier, 3-5 parts of a curing agent, 2-4 parts of other auxiliary materials, and 32-40 parts of water.

[0011] Preferably, the surface coating of the EPS foam mold includes the following raw materials in parts by mass: 26 parts of aggregate, 67 parts of binder, 1.3 parts of dispersant, 7 parts of emulsifier, 4 parts of curing agent, 3.2 parts of other auxiliary materials, and 38 parts of water.

[0012] Preferably, the aggregate is aluminum oxide and silicon oxide in a mass ratio of 1:3-6.

[0013] Preferably, the binder is silica sol.

[0014] Preferably, the dispersant is polyvinyl alcohol and polyacrylamide in a mass ratio of 1:1-2.

[0015] Preferably, the emulsifier is dodecylphenol polyoxyethylene ether.

[0016] Preferably, the other auxiliary materials are sodium fluorosilicate and p-hydroxybenzoic acid, and the mass ratio is 1:0.2-0.6.

[0017] The present invention also provides a method for preparing a surface coating of an EPS foam mold, comprising the following steps:

[0018] (1) diluting the binder with water;

[0019] (2) Then, aggregate, dispersant, emulsifier, curing agent, and other auxiliary materials are added to the binder solution diluted in step (1) and stirred evenly to obtain a surface coating for the EPS foam mold.

[0020] The present invention also provides an application of a surface coating in an enhanced EPS foam mold, comprising the following steps:

[0021] (1) Prepare EPS foam mold: first use a density greater than 30kg / m 3 The EPS foam board is manually spliced ​​or the EPS mold is processed by a CNC mold engraving machine according to the requirements of the mold drawing. Considering that the surface of the EPS mold needs to be coated, a size margin of 1.5-2.0mm needs to be reserved when processing the mold. The prepared EPS foam mold is kept at 30-50℃ for 5-7h to dry and shape, and the EPS foam mold of the workpiece is obtained for standby use;

[0022] (2) preparing surface coating;

[0023] (3) Apply the first layer of coating on the surface of the EPS foam mold of the workpiece: Apply the surface coating evenly on the surface of the EPS foam mold and dry it naturally until the solvent evaporates and no bubbles are generated in the coating;

[0024] (4) Apply a second layer of surface coating to the naturally dried EPS foam mold until a certain coating thickness is reached;

[0025] (5) Dry the EPS foam mold with the second layer of surface coating in a ventilated environment at 40-60℃ for 12-24 hours, take it out and place it naturally. After the surface coating is completely cured, use sandpaper below 200 mesh to polish it smooth. After cleaning, the EPS foam mold can be used for later use.

[0026] Preferably, in step (3), the surface coating is applied until a coating thickness of 0.5-1.0 mm is reached; in step (4), the surface coating is applied until a coating thickness of 1.5-2.0 mm is reached, to ensure that the size of the workpiece after coating is within the size range required by the drawing.

[0027] Compared with the prior art, the present invention has significant and multi-faceted technical advantages, which are specifically reflected in the following aspects:

[0028] (1) The innovative surface coating of the present invention exhibits good adhesion properties after being applied to the surface of the EPS foam mold. This coating can significantly increase the friction between the outer surface of the EPS foam and the liquid casting, thereby ensuring that the liquid casting can be tightly and evenly adhered to the surface of the EPS foam mold during the casting process. This feature effectively avoids the problem of bubbles that may occur when pouring liquid castings, and also greatly reduces the risk of castings falling off, thereby ensuring the integrity and quality stability of the finished castings.

[0029] (2) The surface coating of the present invention not only has excellent adhesion properties, but also has excellent strength. The coating can maintain its stable performance for a long time during use, and the surface of the EPS foam is not easy to tear or break even at high temperatures. This feature enables the present invention to withstand higher temperatures and pressures during the pouring process, thereby further improving the production efficiency and quality of the finished castings.

[0030] (3) During the casting process, the bonding force between the EPS foam surface coating of the present invention and the casting surface is extremely strong. This strong bonding force enables the EPS foam to withstand the huge impact force from the casting without being damaged. This feature not only improves the production efficiency of the casting, but also greatly reduces the risk of mold damage, thereby saving users the cost of repairing and replacing molds.

[0031] (4) The surface coating of the present invention adopts a unique formula and process during the preparation process, so that the coating can quickly form a hard and durable surface after drying. This surface is not only hard and strong, but also has good corrosion resistance and is not easy to deform and crack. This feature enables the present invention to maintain its stable performance even in harsh production environments, thereby ensuring the production quality and production efficiency of castings.

[0032] (5) By applying the high-strength surface coating of the present invention, the number of times the EPS foam mold can be used has been significantly increased, from the original single use to more than three times. This change not only improves the utilization rate of the mold, but also greatly reduces the production cost of the user.

[0033] (6) In addition to increasing the number of uses, the high-strength surface coating of the present invention also significantly extends the service life of the EPS foam mold. This means that users do not need to replace the mold for a longer period of time, thereby further improving casting production efficiency. This advantage can undoubtedly greatly reduce costs for production companies that need to frequently replace molds.

[0034] (7) The surface coating of the present invention has no special requirements on the surface of the EPS foam casting. No matter what kind of treatment the EPS surface has undergone, as long as it meets certain basic requirements, it can be painted with the coating of the present invention. This feature makes the application range of the present invention wider and can meet the needs of different users.

[0035] (8) The surface coating of the present invention enables the EPS foam mold to exhibit excellent performance in many aspects. The mold has high surface finish and high dimensional accuracy, and the surface strength is also significantly improved. These characteristics not only greatly improve the reuse rate of the EPS foam mold, but also make the mold easier and more stable during the demolding process. In addition, the present invention can also balance the demolding and strengthen the stress points, thereby improving the overall strength of the mold, and effectively solving the problems of the EPS foam mold being easily deformed and difficult to demold during demolding. These advantages make the present invention have extremely high application value and development prospects in the casting industry. DETAILED DESCRIPTION

[0036] In order to facilitate a better understanding of the present invention, the following examples are used to illustrate the present invention. These examples belong to the protection scope of the present invention, but do not limit the protection scope of the present invention.

[0037] In an embodiment of the present invention, a surface coating for an EPS foam mold includes the following raw materials in parts by mass: 22-27 parts of aggregate, 63-72 parts of binder, 1.2-1.5 parts of dispersant, 4-8 parts of emulsifier, 3-5 parts of curing agent, 2-4 parts of other auxiliary materials, and 32-40 parts of water;

[0038] The aggregates are aluminum oxide and silicon oxide, with a mass ratio of 1:3-6;

[0039] The binder is silica sol;

[0040] The dispersant is polyvinyl alcohol and polyacrylamide, with a mass ratio of 1:1-2;

[0041] The emulsifier is dodecylphenol polyoxyethylene ether;

[0042] The other auxiliary materials are sodium fluorosilicate and p-hydroxybenzoic acid, and the mass ratio is 1:0.2-0.6.

[0043] The preparation method of the curing agent comprises the following steps:

[0044] S1. Add epichlorohydrin and water into a reaction kettle, stir at 250 r / min, heat to 44° C., drop methanol, stir at 400 r / min, drop potassium hydroxide solution, adjust the pH value of the reaction solution to 9.5, heat to 108° C., and reflux for 5 hours; cool to obtain an epoxy resin solution;

[0045] S2. Add ricinoleic acid dropwise to the epoxy resin solution obtained in step S1, stir at 500 r / min for 32 min, adjust the pH value of the reaction solution to 2.8, raise the temperature to 65° C., and reflux for 4 h; remove water and methanol by reduced pressure distillation, raise the temperature to 127° C., add hydrogen peroxide solution, and stir well for 5 h to obtain a curing agent; the molar ratio of epichlorohydrin, methanol, water, potassium hydroxide, ricinoleic acid, and hydrogen peroxide is 2:2:6.3:1.3:1:2.1.

[0046] The method for preparing the surface coating of the EPS foam mold comprises the following steps:

[0047] (1) diluting the binder with water;

[0048] (2) Then, aggregate, dispersant, emulsifier, curing agent, and other auxiliary materials are added to the binder solution diluted in step (1) and stirred evenly to obtain a surface coating for the EPS foam mold.

[0049] Application of a surface coating in an enhanced EPS foam mold comprises the following steps:

[0050] (1) Preparing an EPS foam mold: firstly processing a metal aluminum mold of a workpiece, and forming an EPS foam mold of the workpiece by foaming the aluminum mold, and then drying and shaping the prepared EPS foam mold at 85-90° C. for 5-7 hours to obtain an EPS foam mold of the workpiece for standby use;

[0051] (2) preparing surface coating;

[0052] (3) Apply the first layer of paint on the surface of the EPS foam mold of the workpiece: Apply the surface paint evenly on the surface of the EPS foam mold until the coating thickness reaches 0.5-1.0mm, and dry it naturally until the solvent evaporates and no bubbles are generated in the paint;

[0053] (4) Apply a second layer of surface coating to the naturally dried EPS foam mold until the coating thickness reaches 1.5-2.0 mm, ensuring that the size of the workpiece after coating is within the size range required by the drawing;

[0054] (5) Dry the EPS foam mold with the second layer of surface coating in a ventilated environment at 40-60℃ for 12-24 hours, take it out and place it naturally. After the surface coating is completely cured, use sandpaper below 200 mesh to polish it smooth. After cleaning, the EPS foam mold can be used for later use.

[0055] Technical principle of the present invention:

[0056] (I) Technical principle of surface coating of EPS foam mold

[0057] 1. Specific functions of each raw material:

[0058] Aggregate: It is composed of aluminum oxide and silicon oxide in a mass ratio of 1:3-6. Aluminum oxide has the characteristics of high hardness, high melting point and good chemical stability, which can significantly improve the hardness and wear resistance of the coating, and enhance the coating's ability to resist external friction and impact. Silicon oxide has stable chemical properties, which can improve the high temperature resistance of the coating, and can also improve the fluidity and filling of the coating, making the coating more uniform when applied, filling the tiny pores on the surface of EPS foam, and improving the surface smoothness.

[0059] Binder: Silica sol is used as a binder, which has good bonding properties and can firmly combine aggregates, dispersants, emulsifiers and other raw materials to form a complete coating structure. It improves the adhesion between the coating and the surface of the EPS foam mold and the casting surface, ensuring that the coating will not fall off easily during use.

[0060] Dispersant: It is composed of polyvinyl alcohol and polyacrylamide in a mass ratio of 1:1-2. Polyvinyl alcohol can reduce the surface tension of the paint, making it easier to disperse solid particles such as aggregates in the paint, prevent particle agglomeration, and improve the stability and uniformity of the paint. Polyacrylamide has a good thickening effect, which can increase the viscosity of the paint, making it difficult for the paint to flow during the painting process. It also helps to improve the suspension of the paint, so that particles such as aggregates are evenly distributed in the paint.

[0061] Emulsifier: Dodecylphenol polyoxyethylene ether as an emulsifier can reduce the interfacial tension between the oil phase and the water phase in the coating, allowing the two to mix evenly to form a stable emulsion system. This helps to improve the stability and storage performance of the coating, so that the coating will not delaminate or break during long-term storage and use. At the same time, the emulsifier can also improve the wettability of the coating, allowing the coating to better wet the EPS foam surface and improve the adhesion of the coating.

[0062] Curing agent: It plays a role in promoting the curing of silica sol, the binder in the coating. It reacts chemically with silica sol to form a three-dimensional network structure, thereby improving the hardness, strength and chemical corrosion resistance of the coating. The addition of curing agent can also shorten the drying time of the coating, so that the coating can meet the use requirements more quickly and improve production efficiency.

[0063] Other auxiliary materials: Sodium fluorosilicate and p-hydroxybenzoic acid are composed of a mass ratio of 1:0.2-0.6. Sodium fluorosilicate can react with silica sol and curing agent to further promote the curing of the coating, improve the density and water resistance of the coating, and enhance the waterproof and corrosion resistance of the coating. P-hydroxybenzoic acid has a bactericidal and antiseptic effect, can inhibit the growth of microorganisms in the coating, prevent the coating from deteriorating during storage and use, and extend the service life of the coating.

[0064] Water: As a solvent and diluent for paint, it can adjust the viscosity and fluidity of the paint, so that the paint reaches a suitable construction consistency and is easy to apply. Water also participates in some chemical reactions, promotes the mixing and dispersion of raw materials, and helps other raw materials to function better.

[0065] 2. Synergy between raw materials

[0066] Aggregates and binders work synergistically. Aggregates provide physical properties such as hardness and wear resistance, while binders firmly bond aggregates to form a solid coating skeleton, which together improve the strength and durability of the coating.

[0067] Dispersants and emulsifiers work together. Dispersants disperse solid particles evenly, and emulsifiers mix the oil phase and the water phase stably. The combination of the two ensures that the coating system is uniform and stable, avoids particle agglomeration and oil-water separation, and improves the construction performance and storage performance of the coating.

[0068] The reaction between the curing agent and the binder silica sol forms a three-dimensional network structure in the coating, enhancing the hardness, strength and corrosion resistance of the coating. Sodium fluorosilicate in other auxiliary materials further promotes the curing reaction, improves the density and water resistance of the coating, and synergizes with the curing agent and binder to improve the comprehensive performance of the coating.

[0069] Water, as a solvent and diluent, provides a medium for the dispersion, mixing and reaction of other raw materials, allowing the raw materials to fully contact and interact with each other, exerting the best synergistic effect, and jointly improving the performance of the coating. The coating has good adhesion, hardness, wear resistance, water resistance and corrosion resistance, etc., and achieves unexpected technical effects such as increased friction, tight adhesion, high temperature resistance, impact resistance, fast drying, and not easy to deform and crack.

[0070] 3. The necessity and importance of controlling the amount of raw materials

[0071] Aggregate dosage: The dosage is between 22-27 parts. Too little will not provide sufficient hardness and wear resistance, causing the coating to be easily worn and scratched; too much will make the fluidity of the coating worse, making it difficult to apply, and the gaps between the aggregates may not be completely filled by the binder, thereby reducing the density and adhesion of the coating.

[0072] Binder dosage: The dosage range of 63-72 parts is critical. Too little can not fully wrap the aggregate and other raw materials, resulting in poor adhesion of the coating and easy falling off; too much will reduce the flexibility of the coating, and it will easily crack after drying, and will also increase costs.

[0073] Dispersant dosage: 1.2-1.5 parts of dispersant. Too little will make it impossible to fully disperse particles such as aggregates, and agglomeration will occur, affecting the performance and appearance of the coating; too much will make the coating viscosity too high, affecting the construction performance.

[0074] Emulsifier dosage: 4-8 parts of emulsifier. Too little can not form a stable emulsion system, the paint is easy to stratify and demulsify; too much will lead to too low surface tension of the paint, and it is easy to cause sagging when brushing.

[0075] Amount of curing agent: 3-5 parts of curing agent. Too little curing reaction will be incomplete, and the hardness, strength and corrosion resistance of the coating will not meet the requirements; too much will make the curing reaction too fast, resulting in a shortened construction time of the coating and may increase the brittleness of the coating.

[0076] Amount of other auxiliary materials: 2-4 parts of other auxiliary materials. Too little sodium fluorosilicate cannot fully promote the curing reaction and improve water resistance, while too much will increase the brittleness of the coating. Too little parahydroxybenzoic acid cannot effectively inhibit the growth of microorganisms, while too much may have an adverse effect on the performance of the coating.

[0077] Amount of water: 32-40 parts of water. Too little will make the paint too viscous and difficult to apply; too much will reduce the solid content of the paint, affecting the thickness and performance of the coating, and prolonging the drying time.

[0078] Within the above-mentioned dosage range, the raw materials can cooperate and work synergistically with each other, so that the coating has good comprehensive performance, achieving unexpected technical effects such as increasing the number of uses of the EPS foam mold from a single time to more than 3 times, thereby improving the service life of the EPS foam mold and casting production efficiency.

[0079] (II) Application technology principle of surface coating in enhanced EPS foam mold

[0080] Friction enhancement principle: After the surface coating is applied to the surface of the EPS foam mold, its microstructure will make the mold surface rougher and have a certain degree of adsorption. When the liquid casting is poured into the mold, the microscopic protrusions and depressions on the coating surface fit into the surface of the liquid casting, increasing the contact area and mechanical bite between the two, thereby effectively increasing the friction between the outer surface of the EPS foam and the surface of the liquid casting, allowing the liquid casting to be tightly bonded to the surface of the EPS foam mold.

[0081] Strength enhancement principle: The surface coating itself has high strength characteristics, which comes from its internal chemical composition and molecular structure. The film-forming substances in the coating will form a tightly cross-linked polymer network structure during the drying and curing process, which gives the coating good mechanical properties. When the coating is applied to the surface of the EPS foam mold and cured, it is like putting a layer of solid armor on the EPS foam, so that the EPS foam can withstand greater stress at high temperatures and is not easy to tear or break.

[0082] Principle of bonding strength enhancement: There are multiple bonding effects between the surface coating and the EPS foam mold and the casting surface. On the one hand, the binder in the coating can form chemical bonds or strong physical adsorption with the molecules on the surface of the EPS foam, so that the coating and the EPS foam are tightly bonded; on the other hand, when pouring the casting, the liquid casting and the coating surface have a physical effect, and form a tight mechanical fit with the coating during the cooling and solidification process, thereby greatly enhancing the bonding between the EPS foam surface coating and the casting surface, so that it can withstand greater impact.

[0083] Drying and performance optimization principle: The formula of the surface coating has been carefully designed, and the solvent in it has a suitable volatilization rate. During the natural drying process, the solvent can evaporate quickly, so that the film-forming substances in the coating can quickly gather and form a continuous film. At the same time, some additives in the coating can promote the cross-linking reaction of the film-forming substances, accelerate the drying speed, and improve the hardness and strength of the surface after drying. In addition, the corrosion-resistant components in the coating can form a protective film on the surface to prevent external corrosive substances from contacting EPS foam and castings, preventing them from corrosion, deformation and cracking.

[0084] Unexpected technical effects:

[0085] Significantly improved casting quality: In traditional EPS foam mold casting, bubbles and shedding are common, which will seriously affect the quality and performance of the casting. After using this surface coating, the liquid casting is closely bonded to the surface of the EPS foam mold, avoiding the generation and shedding of bubbles, making the surface of the cast casting smoother and more complete, and the internal structure more dense, greatly improving the quality and pass rate of the casting, and reducing the generation of defective and waste products. It has important application value in some fields with extremely high requirements for casting quality, such as aerospace, automobile manufacturing, etc.

[0086] The service life of the mold is greatly extended: In general, the surface of the EPS foam mold is easily damaged during the high-temperature pouring process, resulting in a short service life of the mold. The surface coating of the present invention has high strength, high temperature resistance, corrosion resistance, and is not easy to deform and crack, and can effectively protect the EPS foam mold from damage during multiple pouring processes. The number of times the EPS foam mold can be used is increased from a single use of 1 time to more than 3 times, which greatly increases the service life of the mold, reduces the frequency and cost of mold replacement, and improves production efficiency.

[0087] Adaptable to various EPS foam surfaces: Different from some other technologies that require strict pretreatment of the EPS foam surface, the surface coating of the present invention does not have excessive requirements on the surface of the EPS foam casting. Whether the EPS foam surface is smooth or rough, it can be used after simple treatment. This not only reduces the complexity and cost of the process, but also expands the application scope of the technology, so that various types and qualities of EPS foam can be coated with the surface coating to improve their performance and service life.

[0088] Comprehensive performance is fully optimized: The surface coating of the present invention makes the EPS foam mold have the characteristics of high surface finish, good dimensional accuracy and high surface strength. In the demolding process, it can balance the demolding force and strengthen the force points, effectively solving the problems of easy deformation and difficulty in demolding of the EPS foam mold. This not only improves the reuse rate of the mold, but also makes the entire casting process smoother, reduces production interruptions and delays caused by mold problems, improves the continuity and stability of production, and provides strong support for large-scale and efficient casting production.

[0089] In order to make the disclosure of the present invention more complete, it is described below through more specific embodiments.

[0090] Example 1

[0091] A surface coating for an EPS foam mold, comprising the following raw materials, in parts by mass: 22.3 parts of aggregate, 64 parts of binder, 1.2 parts of dispersant, 4.2 parts of emulsifier, 3 parts of curing agent, 2 parts of other auxiliary materials, and 34 parts of water;

[0092] The aggregates are aluminum oxide and silicon oxide, with a mass ratio of 1:3;

[0093] The binder is silica sol;

[0094] The dispersant is polyvinyl alcohol and polyacrylamide, with a mass ratio of 1:1;

[0095] The emulsifier is dodecylphenol polyoxyethylene ether;

[0096] The other auxiliary materials are sodium fluorosilicate and p-hydroxybenzoic acid, and the mass ratio is 1:0.3.

[0097] The preparation method of the curing agent comprises the following steps:

[0098] S1. Add epichlorohydrin and water into a reaction kettle, stir at 250 r / min, heat to 44° C., drop methanol, stir at 400 r / min, drop potassium hydroxide solution, adjust the pH value of the reaction solution to 9.5, heat to 108° C., and reflux for 5 hours; cool to obtain an epoxy resin solution;

[0099] S2. Add ricinoleic acid dropwise to the epoxy resin solution obtained in step S1, stir at 500 r / min for 32 min, adjust the pH value of the reaction solution to 2.8, raise the temperature to 65° C., and reflux for 4 h; remove water and methanol by reduced pressure distillation, raise the temperature to 127° C., add hydrogen peroxide solution, and stir well for 5 h to obtain a curing agent; the molar ratio of epichlorohydrin, methanol, water, potassium hydroxide, ricinoleic acid, and hydrogen peroxide is 2:2:6.3:1.3:1:2.1.

[0100] The method for preparing the surface coating of the EPS foam mold comprises the following steps:

[0101] (1) diluting the binder with water;

[0102] (2) Then, aggregate, dispersant, emulsifier, curing agent, and other auxiliary materials are added to the binder solution diluted in step (1) and stirred evenly to obtain a surface coating for the EPS foam mold.

[0103] Application of a surface coating in an enhanced EPS foam mold comprises the following steps:

[0104] (1) Prepare EPS foam mold: first use a density of 32kg / m 3 The EPS foam board is processed into the EPS mold by using a CNC mold engraving machine according to the requirements of the mold drawing. Considering that the surface of the EPS mold needs to be coated, a size margin of 1.5mm needs to be reserved when processing the mold. The prepared EPS foam mold is kept at 32℃ for 7h to dry and shape, and the EPS foam mold of the workpiece is obtained for standby use;

[0105] (2) preparing surface coating;

[0106] (3) Apply the first layer of paint on the surface of the workpiece EPS foam mold: Apply the surface paint evenly on the surface of the EPS foam mold until the coating thickness reaches 0.6 mm, and dry it naturally until the solvent evaporates and no bubbles are generated in the paint;

[0107] (4) Apply a second layer of surface coating to the naturally dried EPS foam mold until the coating thickness reaches 1.5 mm, ensuring that the size of the workpiece after coating is within the size range required by the drawing;

[0108] (5) Dry the EPS foam mold with the second layer of surface coating in a ventilated environment at 42°C for 23 hours, take it out and place it naturally. After the surface coating is completely cured, use 200-grit sandpaper to polish it smooth. After cleaning, the EPS foam mold can be used for later use.

[0109] Example 2

[0110] A surface coating for an EPS foam mold, comprising the following raw materials, in parts by mass: 23 parts of aggregate, 65 parts of a binder, 1.3 parts of a dispersant, 5 parts of an emulsifier, 3.4 parts of a curing agent, 2.6 parts of other auxiliary materials, and 35 parts of water;

[0111] The aggregates are aluminum oxide and silicon oxide, with a mass ratio of 1:4;

[0112] The binder is silica sol;

[0113] The dispersant is polyvinyl alcohol and polyacrylamide, with a mass ratio of 1:1.2;

[0114] The emulsifier is dodecylphenol polyoxyethylene ether;

[0115] The other auxiliary materials are sodium fluorosilicate and p-hydroxybenzoic acid, with a mass ratio of 1:0.2;

[0116] The preparation method of the curing agent is the same as that of Example 1.

[0117] The method for preparing the surface coating of the EPS foam mold comprises the following steps:

[0118] (1) diluting the binder with water;

[0119] (2) Then, aggregate, dispersant, emulsifier, curing agent, and other auxiliary materials are added to the binder solution diluted in step (1) and stirred evenly to obtain a surface coating for the EPS foam mold.

[0120] Application of a surface coating in an enhanced EPS foam mold comprises the following steps:

[0121] (1) Prepare EPS foam mold: first use a density of 32kg / m 3 The EPS foam board is processed by CNC mold engraving machine according to the requirements of the mold drawing. Considering that the surface of the EPS mold needs to be coated, a size margin of 1.6mm needs to be reserved when processing the mold. The prepared EPS foam mold is kept at 35℃ for 6.5h to dry and shape, and the EPS foam mold of the workpiece is obtained for standby use;

[0122] (2) preparing surface coating;

[0123] (3) Apply the first layer of coating on the surface of the EPS foam mold of the workpiece: Apply the surface coating evenly on the surface of the EPS foam mold until the coating thickness reaches 0.7 mm, and dry it naturally until the solvent evaporates and no bubbles are generated in the coating;

[0124] (4) Apply a second layer of surface coating to the naturally dried EPS foam mold until the coating thickness reaches 1.6 mm, ensuring that the size of the workpiece after coating is within the size range required by the drawing;

[0125] (5) Dry the EPS foam mold with the second layer of surface coating in a ventilated environment at 40°C for 24 hours, take it out and place it naturally. After the surface coating is completely cured, use 200-grit sandpaper to polish it smooth. After cleaning, the EPS foam mold can be used for later use.

[0126] Example 3

[0127] A surface coating for an EPS foam mold, comprising the following raw materials in parts by mass: 24 parts of aggregate, 64 parts of binder, 1.4 parts of dispersant, 4.6 parts of emulsifier, 3.8 parts of curing agent, 2.8 parts of other auxiliary materials, and 34 parts of water;

[0128] The aggregates are aluminum oxide and silicon oxide, with a mass ratio of 1:5;

[0129] The binder is silica sol;

[0130] The dispersant is polyvinyl alcohol and polyacrylamide, with a mass ratio of 1:1.5;

[0131] The emulsifier is dodecylphenol polyoxyethylene ether;

[0132] The other auxiliary materials are sodium fluorosilicate and p-hydroxybenzoic acid, with a mass ratio of 1:0.4;

[0133] The preparation method of the curing agent is the same as that of Example 1.

[0134] The method for preparing the surface coating of the EPS foam mold comprises the following steps:

[0135] (1) diluting the binder with water;

[0136] (2) Then, aggregate, dispersant, emulsifier, curing agent, and other auxiliary materials are added to the binder solution diluted in step (1) and stirred evenly to obtain a surface coating for the EPS foam mold.

[0137] Application of a surface coating in an enhanced EPS foam mold comprises the following steps:

[0138] (1) Prepare EPS foam mold: first use a density of 32kg / m 3 The EPS foam board is processed by CNC mold engraving machine according to the requirements of the mold drawing. Considering that the surface of the EPS mold needs to be coated, a size margin of 1.5mm needs to be reserved when processing the mold. The prepared EPS foam mold is kept at 38℃ for 6 hours to dry and shape, and the EPS foam mold of the workpiece is obtained for standby use;

[0139] (2) preparing surface coating;

[0140] (3) Apply the first layer of paint on the surface of the workpiece EPS foam mold: Apply the surface paint evenly on the surface of the EPS foam mold until the coating thickness reaches 0.8 mm, and dry it naturally until the solvent evaporates and no bubbles are generated in the paint;

[0141] (4) Apply a second layer of surface coating to the naturally dried EPS foam mold until the coating thickness reaches 1.5 mm, ensuring that the size of the workpiece after coating is within the size range required by the drawing;

[0142] (5) Dry the EPS foam mold with the second layer of surface coating in a ventilated environment at 45°C for 20 hours, take it out and place it naturally. After the surface coating is completely cured, use 200-grit sandpaper to polish it smooth. After cleaning, the EPS foam mold can be used for later use.

[0143] Example 4

[0144] A surface coating for an EPS foam mold, comprising the following raw materials, in parts by mass: 26 parts of aggregate, 67 parts of a binder, 1.3 parts of a dispersant, 7 parts of an emulsifier, 4 parts of a curing agent, 3.2 parts of other auxiliary materials, and 38 parts of water;

[0145] The aggregates are aluminum oxide and silicon oxide, with a mass ratio of 1:5;

[0146] The binder is silica sol;

[0147] The dispersant is polyvinyl alcohol and polyacrylamide, with a mass ratio of 1:1.4;

[0148] The emulsifier is dodecylphenol polyoxyethylene ether;

[0149] The other auxiliary materials are sodium fluorosilicate and p-hydroxybenzoic acid, with a mass ratio of 1:0.5;

[0150] The preparation method of the curing agent is the same as that of Example 1.

[0151] The method for preparing the surface coating of the EPS foam mold comprises the following steps:

[0152] (1) diluting the binder with water;

[0153] (2) Then, aggregate, dispersant, emulsifier, curing agent, and other auxiliary materials are added to the binder solution diluted in step (1) and stirred evenly to obtain a surface coating for the EPS foam mold.

[0154] Application of a surface coating in an enhanced EPS foam mold comprises the following steps:

[0155] (1) Prepare EPS foam mold: first use a density of 32kg / m 3 The EPS foam board is processed by CNC mold engraving machine according to the requirements of the mold drawing. Considering that the surface of the EPS mold needs to be coated, a size margin of 1.8mm needs to be reserved when processing the mold. The prepared EPS foam mold is kept at 40℃ for 6 hours to dry and shape, and the EPS foam mold of the workpiece is obtained for standby use;

[0156] (2) preparing surface coating;

[0157] (3) Apply the first layer of coating on the surface of the EPS foam mold of the workpiece: Apply the surface coating evenly on the surface of the EPS foam mold until the coating thickness reaches 0.7 mm, and dry it naturally until the solvent evaporates and no bubbles are generated in the coating;

[0158] (4) Apply a second layer of surface coating to the naturally dried EPS foam mold until the coating thickness reaches 1.8 mm, ensuring that the size of the workpiece after coating is within the size range required by the drawing;

[0159] (5) Dry the EPS foam mold with the second layer of surface coating in a ventilated environment at 52°C for 17 hours, take it out and place it naturally. After the surface coating is completely cured, use 200-grit sandpaper to polish it smooth. After cleaning, the EPS foam mold can be used for later use.

[0160] Example 5

[0161] A surface coating for an EPS foam mold, comprising the following raw materials in parts by mass: 25 parts of aggregate, 67 parts of a binder, 1.3 parts of a dispersant, 6.5 parts of an emulsifier, 4.3 parts of a curing agent, 3.5 parts of other auxiliary materials, and 36 parts of water;

[0162] The aggregates are aluminum oxide and silicon oxide, with a mass ratio of 1:6;

[0163] The binder is silica sol;

[0164] The dispersant is polyvinyl alcohol and polyacrylamide, with a mass ratio of 1:1.2;

[0165] The emulsifier is dodecylphenol polyoxyethylene ether;

[0166] The other auxiliary materials are sodium fluorosilicate and p-hydroxybenzoic acid, with a mass ratio of 1:0.3;

[0167] The preparation method of the curing agent is the same as that of Example 1.

[0168] The method for preparing the surface coating of the EPS foam mold comprises the following steps:

[0169] (1) diluting the binder with water;

[0170] (2) Then, aggregate, dispersant, emulsifier, curing agent, and other auxiliary materials are added to the binder solution diluted in step (1) and stirred evenly to obtain a surface coating for the EPS foam mold.

[0171] Application of a surface coating in an enhanced EPS foam mold comprises the following steps:

[0172] (1) Prepare EPS foam mold: first use a density of 32kg / m 3 The EPS foam board is processed by CNC mold engraving machine according to the requirements of the mold drawing. Considering that the surface of the EPS mold needs to be coated, a size margin of 2.0mm needs to be reserved when processing the mold. The prepared EPS foam mold is kept at 43℃ for 5.5h to dry and shape, and the EPS foam mold of the workpiece is obtained for standby use;

[0173] (2) preparing surface coating;

[0174] (3) Apply the first layer of coating on the surface of the EPS foam mold of the workpiece: Apply the surface coating evenly on the surface of the EPS foam mold until the coating thickness reaches 0.7 mm, and dry it naturally until the solvent evaporates and no bubbles are generated in the coating;

[0175] (4) Apply a second layer of surface coating to the naturally dried EPS foam mold until the coating thickness reaches 2.0 mm, ensuring that the size of the workpiece after coating is within the size range required by the drawing;

[0176] (5) Dry the EPS foam mold with the second layer of surface coating in a ventilated environment at 54°C for 15 hours, take it out and place it naturally. After the surface coating is completely cured, use 200-grit sandpaper to polish it smooth. After cleaning, the EPS foam mold can be used for later use.

[0177] Example 6

[0178] A surface coating for an EPS foam mold, comprising the following raw materials, in parts by mass: 27 parts of aggregate, 70 parts of a binder, 1.4 parts of a dispersant, 8 parts of an emulsifier, 4.8 parts of a curing agent, 4 parts of other auxiliary materials, and 39 parts of water;

[0179] The aggregates are aluminum oxide and silicon oxide, with a mass ratio of 1:4;

[0180] The binder is silica sol;

[0181] The dispersant is polyvinyl alcohol and polyacrylamide, with a mass ratio of 1:2;

[0182] The emulsifier is dodecylphenol polyoxyethylene ether;

[0183] The other auxiliary materials are sodium fluorosilicate and p-hydroxybenzoic acid, with a mass ratio of 1:0.6;

[0184] The preparation method of the curing agent is the same as that of Example 1.

[0185] The method for preparing the surface coating of the EPS foam mold comprises the following steps:

[0186] (1) diluting the binder with water;

[0187] (2) Then, aggregate, dispersant, emulsifier, curing agent, and other auxiliary materials are added to the binder solution diluted in step (1) and stirred evenly to obtain a surface coating for the EPS foam mold.

[0188] Application of a surface coating in an enhanced EPS foam mold comprises the following steps:

[0189] (1) Prepare EPS foam mold: first use a density of 32kg / m 3 The EPS foam board is processed by CNC mold engraving machine according to the requirements of the mold drawing. Considering that the surface of the EPS mold needs to be coated, a size margin of 1.8mm needs to be reserved when processing the mold. The prepared EPS foam mold is kept at 50℃ for 5h to dry and shape, and the EPS foam mold of the workpiece is obtained for standby use;

[0190] (2) preparing surface coating;

[0191] (3) Apply the first layer of paint on the surface of the EPS foam mold of the workpiece: Apply the surface paint evenly on the surface of the EPS foam mold until the coating thickness reaches 1.0 mm, and dry it naturally until the solvent evaporates and no bubbles are generated in the paint;

[0192] (4) Apply a second layer of surface coating to the naturally dried EPS foam mold until the coating thickness reaches 1.8 mm, ensuring that the size of the workpiece after coating is within the size range required by the drawing;

[0193] (5) Dry the EPS foam mold with the second layer of surface coating in a ventilated environment at 60°C for 12 hours, take it out and place it naturally. After the surface coating is completely cured, use 200-grit sandpaper to polish it smooth. After cleaning, the EPS foam mold can be used for later use.

[0194] Comparative Example 1

[0195] The application of the surface coating in the enhanced EPS foam mold is similar to the process of Example 4, except that the surface of the EPS foam mold is not coated with the coating of the present invention, as follows: first use a density of 32kg / m 3 Use a CNC mold engraving machine to process the EPS mold according to the requirements of the mold drawing. Considering that the surface of the EPS mold needs to be coated, a 1.8mm size margin should be reserved when processing the mold. The prepared EPS foam mold is kept at 40℃ for 6 hours to dry and shape, and the EPS foam mold of the workpiece is ready for use.

[0196] (I) Application of mold

[0197] The molds of Examples 1-6 and Comparative Example 1 were used for mold shaping, and the demolding state was observed. The experiment found that the EPS foam mold with the surface composite coating of the present invention has the characteristics of high surface finish, good dimensional accuracy and high surface strength, which can greatly improve the reuse rate of the EPS foam mold. It can balance the demolding and strengthen the stress points, improve the overall strength of the mold, and solve the problems of easy deformation and difficulty in demolding of the EPS foam mold; the simple EPS foam mold in Comparative Example 1 has a rough surface and low strength. In the actual production process, the mold is easy to deform and difficult to demold, and can only be used once.

[0198] (II) Comparison of various molds

[0199] The EPS foam molds prepared in Examples 1-6 of the present invention were compared and analyzed with the mold types commonly used for casting wear-resistant castings such as high manganese steel (including metal molds, wooden molds and EPS foam molds), and the production cycle, cost and respective advantages and disadvantages of a single mold were evaluated. The results are summarized in Table 1 below.

[0200]

[0201]

[0202] As can be seen from the above table: the EPS foam mold with enhanced surface coating of the present invention has shown significant advantages in terms of manufacturing cycle, and its production cycle is greatly shortened compared with the traditional mold manufacturing method. This innovative design not only greatly improves production efficiency, but also ensures that the mold can be quickly put into practical application, effectively shortening the overall cycle from product design to market.

[0203] What is more worth mentioning is that the composite mold has excellent durability and can withstand the test of multiple times (at least 3 times or more). This feature breaks the limitations of traditional molds in service life and significantly improves the reuse rate of the mold, thereby further reducing production costs and resource waste.

[0204] In terms of performance, the mold of the present invention cleverly combines the dual advantages of wooden molds and metal molds. It inherits the characteristics of wooden molds that are light, easy to process and low in cost, while drawing on the advantages of metal molds in terms of strength and durability, forming a new type of mold material that is both light and strong. This unique combination allows the mold to maintain flexibility and easy operation while also having sufficient stability and durability, meeting the strict requirements of complex casting processes on mold performance.

[0205] In addition, the surface coating enhanced EPS foam mold of the present invention also inherits the significant advantages of rapid manufacturing and low cost of foam molds. By adopting advanced foam molding technology and efficient surface coating treatment technology, the mold manufacturing process is simplified, the production cycle is greatly shortened, and the cost is effectively controlled. This ability to quickly respond to market changes and produce at low cost makes the mold stand out in the fiercely competitive casting industry and become an ideal choice for the production of wear-resistant castings such as high manganese steel.

[0206] Compared with the metal molds, wooden molds and traditional EPS foam molds widely used in the market, the mold of the present invention has shown more superior performance in many aspects. It has not only achieved significant breakthroughs in manufacturing cycle, durability and cost-effectiveness, but also has shown higher casting accuracy and better casting quality in practical applications. Therefore, it can be predicted that the EPS foam mold enhanced by the surface coating of the present invention will play an increasingly important role in future casting production, and its application prospects are broad, and it is worth promoting and applying vigorously.

[0207] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A surface coating for an EPS foam mold, characterized in that: In parts by mass, the following raw materials are included: 22-27 parts of aggregate, 63-72 parts of binder, 1.2-1.5 parts of dispersant, 4-8 parts of emulsifier, 3-5 parts of curing agent, 2-4 parts of other auxiliary materials, and 32-40 parts of water.

2. The surface coating of the EPS foam mold according to claim 1, characterized in that: In parts by mass, the following raw materials are included: 26 parts of aggregate, 67 parts of binder, 1.3 parts of dispersant, 7 parts of emulsifier, 4 parts of curing agent, 3.2 parts of other auxiliary materials, and 38 parts of water.

3. The surface coating of the EPS foam mold according to claim 1 or 2, characterized in that: The aggregates are aluminum oxide and silicon oxide, and the mass ratio is 1:3-6.

4. The surface coating of the EPS foam mold according to claim 1 or 2, characterized in that: The binder is silica sol.

5. The surface coating of the EPS foam mold according to claim 1 or 2, characterized in that: The dispersant is polyvinyl alcohol and polyacrylamide, and the mass ratio is 1:1-2.

6. The surface coating of the EPS foam mold according to claim 1 or 2, characterized in that: The emulsifier is dodecylphenol polyoxyethylene ether.

7. The surface coating of the EPS foam mold according to claim 1 or 2, characterized in that: The other auxiliary materials are sodium fluorosilicate and p-hydroxybenzoic acid, and the mass ratio is 1:0.2-0.

6.

8. A method for preparing a surface coating of an EPS foam mold according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) diluting the binder with water; (2) Then, aggregate, dispersant, emulsifier, curing agent, and other auxiliary materials are added to the binder solution diluted in step (1) and stirred evenly to obtain a surface coating for the EPS foam mold.

9. Use of a surface coating prepared according to the method of claim 8 in a reinforced EPS foam mold, characterized in that: The following steps are involved: (1) Prepare EPS foam mold: first use a density greater than 30kg / m 3 The EPS foam board is manually spliced ​​or the EPS mold is processed by a CNC mold engraving machine according to the requirements of the mold drawing. Considering that the surface of the EPS mold needs to be coated, a size margin of 1.5-2.0mm needs to be reserved when processing the mold. The prepared EPS foam mold is kept at 30-50℃ for 5-7h to dry and shape, and the EPS foam mold of the workpiece is obtained for standby use; (2) preparing surface coating; (3) Apply the first layer of coating on the surface of the EPS foam mold of the workpiece: Apply the surface coating evenly on the surface of the EPS foam mold and dry it naturally until the solvent evaporates and no bubbles are generated in the coating; (4) Apply a second layer of surface coating to the naturally dried EPS foam mold until a certain coating thickness is reached; (5) Dry the EPS foam mold with the second layer of surface coating in a ventilated environment at 40-60℃ for 12-24 hours, take it out and place it naturally. After the surface coating is completely cured, use sandpaper below 200 mesh to polish it smooth. After cleaning, the EPS foam mold can be used for later use.

10. The use of the surface coating according to claim 9 in a reinforced EPS foam mold, characterized in that: In step (3), the surface paint is applied until the coating thickness reaches 0.5-1.0 mm; in step (4), the surface paint is applied until the coating thickness reaches 1.5-2.0 mm, ensuring that the size of the workpiece after coating is within the size range required by the drawing.

Images