Epoxy resin paint is widely used in industry, construction, transportation and other fields due to its excellent anti-corrosion performance, high strength and chemical resistance. However, a question that is often discussed is: Does epoxy resin paint need bottom paint? If so, what is the best bottom paint? In response to this question, this article will discuss in depth the characteristics of epoxy resin paint, the importance of bottom paint and the selection criteria of the best bottom paint to help users scientifically judge and optimize the coating effect.
What is epoxy resin paint?
Epoxy resin paint is an anti-corrosion paint with epoxy resin as the main component and a curing agent. It forms a tough coating film through chemical cross-linking reaction and has the following significant characteristics:
● Excellent adhesion: epoxy resin paint has strong adhesion to surfaces such as metal and concrete.
● Chemical resistance: It can resist the erosion of chemicals such as acids, alkalis and salts.
● High strength: The coating film formed after curing has high hardness and excellent impact resistance.
● Good shielding: It has extremely low water vapor permeability and can effectively prevent corrosive media from entering the substrate.
Although epoxy resin paint has excellent performance, whether it needs primer still depends on the construction requirements and specific application environment.
Does epoxy resin paint need bottom paint?
The answer is not simple and needs to be analyzed in combination with the following factors:
1. Substrate type
● Metal substrate: Direct application of epoxy resin paint may not fully exert its adhesion. The metal surface is smooth and easily oxidized or rusted, so bottom paint is usually required to enhance adhesion and provide preliminary anti-corrosion protection.
● Concrete substrate: The concrete surface is porous and rough. Direct application of epoxy resin paint may cause the paint to penetrate into the pores and fail to form a uniform coating. The role of bottom paint here is to close the pores and provide a flat coating foundation.
● Plastic or glass substrate: These materials have smooth surfaces and poor adhesion, and usually require primer as a bridging layer.
2. Construction environment
● Corrosive environment: In high acid, alkali and salt concentrations or marine climates, the use of bottom paint is particularly important, which can provide a stronger protective foundation for epoxy resin paint.
● Ordinary environment: If the substrate surface has been treated and the corrosion risk is low, consider omitting the bottom paint.
3. Formula design of epoxy resin paint
Some epoxy resin paints are specially designed with strong "bottom-to-surface integration" performance and can be directly applied without bottom paint. However, this type of paint is usually more expensive and has strict requirements on construction conditions.
Overall, in most cases, epoxy resin paint requires bottom paint, especially when the substrate requires high adhesion and long-term corrosion protection.
Why does epoxy resin paint need bottom paint?
Bottom paint is not only the first barrier of the coating system, but also improves the performance of the overall coating. Its main functions include:
● Improve adhesion: bottom paint can establish a strong connection bridge between the substrate and epoxy resin paint to prevent the coating from peeling or falling off.
● Seal the substrate surface: Seal porous materials (such as concrete) to prevent paint penetration and reduce material waste.
● Provide initial anti-corrosion protection: Using anti-rust bottom paint on metal surfaces can delay oxidation or corrosion of the substrate.
● Improve coating quality: bottom paint can fill minor defects on the surface of the substrate and ensure the surface flatness and smoothness of epoxy resin paint.
● Save costs: The price of bottom paint is usually lower than that of epoxy resin paint. Reasonable use of primer can reduce the amount of epoxy resin paint and reduce the cost of coating.
What is the best bottom paint for epoxy resin paint?
To choose a suitable bottom paint, you need to combine the substrate, the use environment and the coating process. The following are several common bottom paint types and their characteristics:
1. Epoxy bottom paint
Epoxy bottom paint is the best partner for epoxy resin paint. It uses epoxy resin as the main ingredient, has strong adhesion and anti-corrosion properties, and can form a perfect chemical bond with epoxy resin paint.
● Scope of application: substrates such as metal, concrete, and wood.
● Advantages: good compatibility with epoxy resin paint, strong chemical resistance, and excellent adhesion.
2. Polyurethane bottom paint
Polyurethane bottom paint uses polyurethane resin as the base material and has good adhesion and flexibility. It performs well on some special substrates (such as aluminum alloys and plastics).
● Scope of application: substrates with large deformation or vibration.
● Advantages: strong flexibility and good impact resistance.
3. Alkyd bottom paint
Alkyd bottom paint is relatively low in price and is mainly used in ordinary environments with low anti-corrosion requirements.
● Scope of application: metal substrates such as steel.
● Advantages: low cost and convenient construction.
4. Inorganic zinc silicate bottom paint
Inorganic zinc silicate bottom paint is a high-performance anti-rust bottom paint, especially suitable for extreme corrosive environments.
● Scope of application: chemical equipment, marine facilities, etc.
● Advantages: excellent high temperature resistance and corrosion resistance.
What are the key points to choose the best bottom paint?
1. Substrate type
● Steel: Epoxy bottom paint or inorganic zinc silicate bottom paint is preferred.
● Concrete: Epoxy bottom paint is the best choice.
● Plastic or glass: polyurethane bottom paint or specially formulated epoxy bottom paint.
2. Use environment
● Highly corrosive environment: Inorganic zinc silicate bottom paint and epoxy bottom paint perform better.
Ordinary environment: Alkyd bottom paint is sufficient to meet the needs.
3. Construction requirements
● If the construction time is tight, choose polyurethane bottom paint with a faster drying speed.
If the coating performance requirements are high, epoxy bottom paint with strong chemical compatibility with epoxy resin paint should be given priority.
4. Budget factors
● Epoxy bottom paint has excellent performance but high cost, suitable for high-demand scenes.
Alkyd bottom paint is economical and practical, and is the choice for projects with limited budgets.
Looking for reliable industrial paint at discounted prices?
Huaren Chemical Industry Co., Ltd. has been a specialized manufacturer and supplier since 1994, offering OEM/ODM solutions for buyers worldwide. Our China-based factory features 30 modern production lines and an annual output exceeding 20,000 tons.
From epoxy resin paints to eco-friendly water-based paints, our product range is extensive and customizable. We offer factory prices, flexible purchasing terms, and reliable after-sales support. Trusted by clients in Europe, Africa, and Southeast Asia, Huaren Chemical is your ideal partner for large orders and long-term cooperation.
