Hubei Tianlang Nanotechnology Co., Ltd

Classification of Anti-Corrosion Coatings and Application of Barium Sulfate in Anti-Corrosion Coatings

China boasts a vast market for anti-corrosion coatings, with demand for marine heavy-duty anti-corrosion coatings growing at an average annual rate exceeding 20%. However, compared to international standards, the domestic coatings industry has long been in a stage of lagging behind, imitation, and catch-up development. Over 80% of the domestic heavy-duty anti-corrosion coatings market is monopolized by international giants. Therefore, a deep understanding of the classification of anti-corrosion coatings and the application of barium sulfate within them has become an essential core skill for downstream anti-corrosion manufacturers.

I. Main Application Areas of Anti-Corrosion Coatings

Anti-corrosion coatings are widely used in the following five major areas:

1. Emerging Marine Engineering: Offshore facilities, coastal and bay structures, offshore oil drilling platforms.

2. Modern Transportation: Highway guardrails, bridges, boats/ships, containers, trains and railway facilities, automobiles, airport facilities.

3. Energy Industry: Hydraulic equipment, water tanks, gas tanks, petroleum refining equipment, petroleum storage equipment (pipelines, oil tanks), power transmission and transformation equipment, nuclear power, coal mines.

4. Large Industrial Enterprises: Papermaking equipment, pharmaceutical equipment, food chemical equipment, internal and external walls of metal containers, pipelines, storage tanks in chemical, steel, and petrochemical plants, mining and smelting, cement plant equipment, floors, walls, and cement components exposed to corrosive media.

5. Municipal Facilities: Gas pipelines and their facilities (e.g., gas holders), natural gas pipelines, drinking water facilities, waste treatment equipment, etc.

II. Overview and Classification of Anti-Corrosion Coatings

Anti-corrosion coatings are an indispensable category within paint and coatings, primarily divided into conventional anti-corrosion coatings and heavy-duty anti-corrosion coatings:

• Conventional Anti-Corrosion Coatings: Provide anti-corrosion protection for metals and other substrates under general environmental conditions, extending their service life.

• Heavy-Duty Anti-Corrosion Coatings: Refers to coatings that can be applied in relatively harsh corrosive environments and offer a significantly longer protection cycle than conventional anti-corrosion coatings.

Anti-corrosion coatings can be classified in various ways:

• By Primary Film-Forming Substance (Composition):

1. Epoxy Anti-Corrosion Coatings

2. Polyurethane Anti-Corrosion Coatings

3. Acrylic Anti-Corrosion Coatings

4. Inorganic Anti-Corrosion Coatings

5. Ceramic Anti-Corrosion Coatings

6. Chlorinated Polyvinyl Chloride (CPVC) Anti-Corrosion Coatings

7. Chlorinated Rubber Anti-Corrosion Coatings

8. Highly Chlorinated Polyethylene (HCPE) Anti-Corrosion Coatings

• By Primary Application:

1. Anti-Corrosion Coatings for Rubber

2. Pipeline Anti-Corrosion Coatings

3. Marine Anti-Corrosion Coatings

4. Metal Anti-Corrosion Coatings

5. Automotive Anti-Corrosion Coatings

6. Structural Steel Anti-Corrosion Coatings

7. Furniture Anti-Corrosion Coatings

• By Solvent Type:

1. Water-Based Anti-Corrosion Coatings

2. Solvent-Based (Oil-Based) Anti-Corrosion Coatings

III. Anti-Rust Paints and Anti-Corrosion Coatings for Building Steel Structures

• Anti-Rust Paints: Primarily used to protect metal surfaces from chemical or electrochemical corrosion by the atmosphere, seawater, etc. Their main components are anti-corrosion pigments and film-forming substances.

• Nomenclature: Typically named after the anti-rust pigment, e.g., Red Lead Anti-Rust Paint, Iron Oxide Red Anti-Rust Paint.

• Classification by Mechanism of Action:

1. Physically Acting Anti-Rust Paints: Rely on the combination of pigment and binder to form a dense film that blocks the ingress of corrosive media (e.g., Iron Oxide Red, Aluminum Powder, Graphite Anti-Rust Paints).

2. Chemically Acting Anti-Rust Paints: Rely on the chemical rust-inhibiting action of the anti-rust pigment (e.g., Red Lead Anti-Rust Paint).

3. Electrochemically Acting Anti-Rust Paints: Provide protection through electrochemical principles (e.g., Zinc-Rich Primers).

4. Comprehensive Action Anti-Rust Paints: Incorporate multiple protection mechanisms mentioned above. Given that steel constitutes 95% of metal usage and 70% is exposed to rust-prone atmospheres, preventing atmospheric corrosion of steel is the primary focus of anti-rust work.

• Building Steel Structure Anti-Corrosion Coatings: Primarily serve the protection of steel structures. Core categories include:

I. Metal Anti-Corrosion Coatings: Possess excellent rust resistance, resistance to chemical media corrosion, abrasion resistance, water resistance (fresh and saltwater), salt spray resistance, resistance to microbial attack, electrical insulation, resistance to stray currents, heat resistance, and resistance to thermal shock. Applications: External walls of buried pipelines, liquid storage tanks and bottoms, steel structures in underwater and alternating wet/dry environments, concrete anti-corrosion coating.

II. Seawater Immersion Resistant Anti-Corrosion Coatings: Exhibit good abrasion resistance, impact resistance, extremely excellent resistance to media penetration, and outstanding resistance to acids, alkalis, salts, oilfield wastewater, and brine/seawater. Chemical characteristics include good adhesion to the substrate. The coating demonstrates exceptional weather resistance, anti-aging properties, radiation resistance, abrasion resistance, impact resistance, high and low-temperature resistance; stable conductivity meeting anti-static requirements while ensuring long coating life. Resistant to heavy corrosion with long anti-corrosion life, high thermal shock resistance, high temperature and friction resistance. After film formation, the coating exhibits high hardness, excellent adhesion, and impact resistance.

III. Major Types and Representative Products of Heavy-Duty Anti-Corrosion Coatings

    Marine Coatings and Container Coatings

    Heavy-Duty Anti-Corrosion Coatings for Chemical Industry

    Railway, Highway Bridge and Structural Steel Anti-Corrosion Coatings

    Infrastructure Coatings

    Heavy-duty anti-corrosion coatings encompass a rich variety of specific types. Representative products include:

• Epoxy Resin Paints: High-build epoxy zinc-rich primer, epoxy micaceous iron oxide (MIO) anti-rust paint, epoxy glass flake coating, epoxy coal tar pitch paint, epoxy floor paint.

• Chlorinated Vinyl Paints: Primer, topcoat, machine tool paint, hammer finish paint, fire-retardant paint, anti-corrosion paint, varnish, chlorinated polyvinyl chloride putty.

• Chlorinated Rubber Paints: Various color topcoats, aluminum powder anti-rust primer, anti-rust primer, iron oxide red aluminum powder anti-rust paint, ship bottom anti-fouling paint.

• Acrylic Paints: Acrylic polyurethane clear topcoat, various color acrylic polyurethane enamel, road marking paint.

• Fluorocarbon Paints: Various color fluorocarbon anti-corrosion coatings, metallic fluorocarbon paint, fluorocarbon exterior wall coatings.

• Alkyd Paints: Micaecous iron oxide alkyd anti-rust paint, various color alkyd hull paint, various color alkyd enamel.

• Silicone Heat-Resistant Paints: Various color silicone air-drying/baking paints, heat-resistant insulating paint, aluminum powder heat-resistant paint, muffler heat-resistant paint.

• Solvent-Free Anti-Corrosion Coatings: Solvent-free epoxy glass flake heavy-duty anti-corrosion coating, solvent-free epoxy coal tar pitch coating, solvent-free pipeline internal drag-reducing coating, solvent-free self-leveling floor paint.

• Special Anti-Corrosion Coatings: Vinyl wash primer, inorganic zinc-rich primer, water-based inorganic zinc-rich primer, glass paint, formwork paint.

• Other Types: Inorganic zinc silicate shop primer (standard/high zinc), various color silicone heat-resistant paint (300°C/400°C), various color alkyd hull paint (white/black/green/blue-grey/light grey), deck paint (purple-red/grass green alkyd), aluminum pitch/bitumen ship bottom paint, various anti-fouling paints (wooden ship bitumen/iron ship brown bitumen/long-lasting), coal tar pitch varnish, series of epoxy coal tar pitch paints (primer/topcoat/anti-rust paint/high-build aluminum anti-rust paint/high-build anti-rust paint/pipeline special paint), bitumen varnish, high-temperature resistant anti-corrosion coating (1800°C), inorganic anti-corrosion coating, bitumen boiler paint, etc.

IV. Application of Barium Sulfate in Anti-Corrosion Coatings

Barium sulfate (BaSO₄), as an important functional filler, plays a key role in anti-corrosion coatings:

• Core Advantages:

• Low oil absorption (10-12), high density (~4.35 g/cm³).

• Smooth near-spherical particle structure imparts excellent filling properties.

• Significantly enhances film strength, hardness, and abrasion resistance.

• Improves film hiding power, aiding in achieving and maintaining high gloss.

• Possesses good anti-settling, dispersion, and suspension properties.

• Exhibits properties such as resistance to weathering corrosion, thermal shock, insulation, weather resistance, high temperature resistance, and resistance to acids, alkalis, and salts, along with a long shelf life.

• Application Effects: Adding barium sulfate powder to acid and alkali-resistant anti-corrosion coatings can significantly enhance corrosion resistance performance. The resulting surface film provides long-lasting protection in applications such as rubber anti-corrosion, marine anti-corrosion, metal anti-corrosion, automotive anti-corrosion, pipeline anti-corrosion, furniture anti-corrosion, container anti-corrosion, as well as railway, highway bridge, and structural steel anti-corrosion. It offers effective surface protection for high-speed trains, aircraft, aerospace vehicles, ships, vessels, and military vessels.

• Wide Application: Barium sulfate powder is commonly added in specific proportions to automotive paints, water/solvent-based industrial paints, wood paints, formwork paints, panel paints, alkyd paints, road paints, floor paints, metal anti-rust paints, powder coatings, PCB inks, interior and exterior wall coatings produced by domestic and international paint manufacturers. Furthermore, barium sulfate is also widely used in high-gloss general-purpose plastics, engineering plastics, high-gloss coatings, adhesives, silicone rubber, and other fields.