MIL-PRF-22750: Epoxy Coating for Military and Aerospace Equipment

Protective coatings might not be the first thing people think about when they picture military technology, but they are critical to ensuring long-term performance in harsh environments. From vehicles and control panels to lighting housings and weapon systems, surface coatings protect against corrosion, fuel, oils, and UV exposure. One of the most trusted coating specifications in defense and aerospace applications is MIL-PRF-22750, a standard that defines the performance of high-durability epoxy paints.

This specification ensures that coatings used on mission-critical equipment provide exceptional adhesion, chemical resistance, and environmental stability while meeting strict safety and durability criteria.

What is MIL-PRF-22750

MIL-PRF-22750 is a United States military performance specification that covers epoxy coatings used on primed metal, composite, or plastic surfaces. These coatings are typically applied to components that require long-term corrosion protection and chemical resistance.

The standard originated in the 1960s and has been revised multiple times to meet evolving environmental and performance requirements. It is currently managed by the Naval Air Systems Command (NAVAIR) and widely used by the U.S. Army, Navy, and Air Force, as well as allied defense industries.

Epoxy coatings made to MIL-PRF-22750 are two-component systems consisting of a resin base and curing agent. Once applied and cured, they form a dense, cross-linked film that resists chemicals, abrasion, and extreme environmental exposure.

Key properties and performance requirements

MIL-PRF-22750 coatings must meet specific mechanical, chemical, and environmental performance criteria. Below is an overview of the most important characteristics:

Property	Requirement
Adhesion	Must remain intact under cross-cut or tape-pull tests after curing
Hardness	High pencil hardness after full cure (usually H or higher)
Chemical resistance	Must resist fuels, hydraulic fluids, lubricants, and cleaning solvents
Corrosion protection	No blistering or rust after 1000-hour salt fog exposure
Flexibility	Must withstand 180-degree bend without cracking or delamination
Color stability	Must maintain color and gloss under UV and heat exposure
VOC limits	Formulations must comply with environmental and occupational health regulations

These coatings are normally applied over a qualified primer, often one meeting MIL-PRF-23377 or MIL-DTL-53022, to ensure maximum adhesion and corrosion resistance.

Types and classes

MIL-PRF-22750 defines several types and classes to suit different operating environments and application methods.

Types: Usually distinguish between standard, low-VOC, and high-solids versions.
Classes: Determine color, finish, and infrared reflectance properties. For example, flat finishes are preferred for tactical use to reduce glare and visibility.

Coatings can be applied by spray, brush, or roller and typically require curing at ambient temperature or with mild heat. When fully cured, the film forms a hard, glossy, and chemical-resistant surface that can last for decades under proper maintenance.

Applications

MIL-PRF-22750 epoxy coatings are used across all branches of the military and by defense contractors. Common applications include:

Vehicle exteriors and interiors: Tactical vehicles, armored transports, and support equipment.
Aircraft components: Structural panels, pylons, and landing gear housings.
Lighting systems: Protective housings, connectors, and brackets exposed to weather and mechanical stress.
Naval systems: Deck equipment and control panels exposed to saltwater and humidity.
Ground support and test equipment: Coated to resist hydraulic fluids, oils, and de-icing chemicals.

Because these coatings perform well across multiple substrates, they are also used in civil aerospace, heavy industry, and offshore energy sectors.

Comparison with other coating specifications

Specification	Type	Typical Use
MIL-PRF-22750	Two-component epoxy	High-durability general use, excellent chemical resistance
MIL-DTL-53039	Polyurethane	Exterior topcoat with UV resistance and flexibility
MIL-PRF-23377	Epoxy primer	Corrosion-resistant primer under topcoats
MIL-PRF-85285	Polyurethane	Aircraft and vehicle topcoat, good weathering performance

In many cases, a MIL-PRF-22750 epoxy serves as an intermediate or final layer below a polyurethane topcoat to combine strength, corrosion resistance, and color stability.

Advantages

Excellent chemical and solvent resistance
Outstanding adhesion to properly prepared metal or composite substrates
Proven corrosion protection under long-term exposure
Compatible with a wide range of primers and topcoats
Available in low-VOC and environmentally compliant formulations

Because of its hardness, it is sometimes less flexible than polyurethane coatings, so designers often balance performance by using it in layered coating systems.

Environmental and safety compliance

Modern revisions of MIL-PRF-22750 include strict limits on volatile organic compounds (VOCs) and hazardous materials. Formulations must comply with EPA and DoD environmental regulations, making them suitable for use in restricted workspaces and global defense contracts.

Manufacturers are required to qualify products through official Qualified Products Lists (QPL) maintained by the Department of Defense. Only coatings listed on the QPL can be specified in military or government projects.

Frequently asked questions