Methyl Isobutyl Ketone (MIBK)
CAS 108-10-1Methyl Isobutyl Ketone (MIBK, 4-methylpentan-2-one, CAS 108-10-1) is a medium-boiling ketone solvent with a slow evaporation rate and strong solvency for a wide range of resin systems.
Key Features
- ✓Medium-boiling ketone — slower evaporation for improved coating flow and leveling
- ✓Strong solvency for epoxy, vinyl, chlorinated rubber resin systems
- ✓Good warning odor at low concentrations — practical occupational exposure awareness
- ✓Dissolves heavy hydrocarbon contamination (cutting oils) for metal bonding surface prep
- ✓Class IC flammable (flash point 16°C) — lower immediate hazard than acetone/MEK
Specifications
| Parameter | Value |
|---|---|
| Purity | ≥99.0% by GC |
| Appearance | Clear, colorless liquid |
| CAS Number | 108-10-1 |
| Flash point | 16°C (ASTM D93) |
| Boiling point | 117°C |
| Density (20°C) | 0.801 g/cm³ |
| Relative evaporation rate | ~0.6 (n-BuAc = 1.0) |
FAQ
MIBK and MEK both dissolve epoxy resins effectively and are both used in epoxy primer formulations. MEK (boiling point 80°C) evaporates approximately 5x faster than MIBK (boiling point 117°C), making MEK more suitable for fast-drying primers and quick application cycles. MIBK is preferred in epoxy primers where: (1) longer open time and brush mark flow-out is required; (2) high-temperature application conditions where MEK evaporates too fast; (3) better surface penetration into porous or rough substrates; (4) solvent blends requiring a slower-evaporating component for proper film formation. In practice, many epoxy primer formulations use a blend of MEK and MIBK (and sometimes xylene or aromatic naphtha) to achieve the target evaporation profile for the specific application method (spray, brush, or roll).