August 25, 2026 · VASTEC Chemical
MEKO: The Essential Anti-Skinning Agent for Modern Coatings and Sealants
For paint and coating manufacturers, one of the most frustrating quality issues is skinning — the formation of a solid film on the surface of liquid paint during storage. This premature oxidation wastes material, clogs containers, and creates application defects. The industry-standard solution? Methyl Ethyl Ketoxime (MEKO).
What Is MEKO?
MEKO (CAS: 96-29-7) is the oxime derivative of methyl ethyl ketone, with the chemical formula C₄H₉NO. It is a colorless to pale yellow liquid with a density of approximately 0.923 g/cm³ and a boiling point of 152°C. In the coatings industry, MEKO is primarily valued for its ability to inhibit oxidation reactions that cause surface skin formation.
How MEKO Prevents Skinning
When alkyd paints and oxidatively-curing coatings are exposed to air, the surface undergoes crosslinking through oxidation — the same process that allows the paint to dry on a wall, but happening prematurely in the can. MEKO works by:
- Radical scavenging: MEKO reacts with free radicals that initiate the oxidation chain reaction, effectively pausing the curing process until the paint is applied
- Oxygen barrier: At the paint surface, MEKO creates a temporary protective layer that reduces oxygen contact with the coating
- Controlled evaporation: Once the can is opened and the paint is applied, MEKO evaporates quickly (boiling point 152°C), allowing normal drying to proceed without interference
Key Applications
1. Anti-Skinning Agent for Paints and Inks
This is MEKO's primary application. It is added to air-drying alkyd paints, offset printing inks, and letterpress inks at typical dosages of 0.1–0.5% by weight. The result is dramatically extended shelf life — from weeks to months — without affecting drying time or film properties.
2. Silicone Sealant Crosslinker
In RTV (room-temperature vulcanizing) silicone sealants, MEKO serves as a crosslinking agent that controls the cure rate. It provides stable, predictable curing while maintaining long pot life during application. This makes it essential for construction sealants, automotive gaskets, and electronic encapsulation.
3. Isocyanate Blocking Agent
In polyurethane coating systems, MEKO blocks isocyanate groups to create stable, one-component formulations. The blocked isocyanate releases at elevated temperatures during baking, enabling controlled crosslinking. This technology is widely used in automotive OEM coatings and industrial maintenance coatings.
4. Chemical Intermediate
Beyond coatings, MEKO is used in the synthesis of hydroxylamine sulfate and hydroxylamine hydrochloride — important reagents in pharmaceutical manufacturing and analytical chemistry. It also finds use in wood preservation and metalworking fluids.
Technical Specifications
| CAS Number | 96-29-7 |
| Molecular Formula | C₄H₉NO |
| Molecular Weight | 87.12 g/mol |
| Appearance | Colorless to pale yellow liquid |
| Purity | ≥99.5% |
| Water Content | ≤0.5% |
| Boiling Point | 152°C |
| Density | 0.923 g/cm³ |
| UN Number | UN2810 (Class 6.1) |
| Packaging | 190 kg steel drums |
Handling and Safety
MEKO is classified as a toxic liquid (UN2810, Hazard Class 6.1). Standard precautions include wearing chemical-resistant gloves, safety goggles, and adequate ventilation during handling. The product should be stored in tightly sealed containers away from strong oxidizers. Detailed safety data is available in the product SDS.
VASTEC Supply Capabilities
VASTEC supplies high-purity MEKO (≥99.5%) to coatings manufacturers, adhesive formulators, and chemical distributors across 30+ countries. Our MEKO is:
- Batch-tested with Certificate of Analysis (COA) provided
- Packed in 190 kg steel drums on pallets, stretch-wrapped for secure ocean transport
- Shipped FOB from Chinese ports with full export documentation
- Available in trial quantities for formulation testing
Whether you're formulating alkyd paints, silicone sealants, or polyurethane coatings, MEKO is a proven, cost-effective additive that protects your product quality from production to application.