2,2,4-Trimethyl-1,3-pentanediol monoisobutyrate
2,2,4-Trimethyl-1,3-pentanediol monoisobutyrate, best known by the trade name Texanol, is the benchmark coalescent that lets hard latex binders form continuous films at room temperature.
TMPD-MIB is an ester alcohol (molecular weight 216.32 g/mol): a branched diol in which one hydroxyl has been esterified with isobutyric acid. Commercial product is a mixture of two closely related isomers. It is a clear, low-odor liquid with very low water solubility and a boiling point around 250 °C.
In waterborne latex paints, TMPD-MIB is a coalescent (film-formation aid). It partitions into the polymer particles and softens them temporarily, lowering the minimum film formation temperature (MFFT) so particles can deform and fuse into a continuous film. It then leaves the film slowly by evaporation, and the film recovers its hardness and block resistance.
TMPD-MIB has low acute toxicity and is not classified as hazardous in many jurisdictions, though it can irritate eyes. It is combustible, so keep it away from ignition sources, and follow the SDS. Store in closed containers at ambient temperature.
The minimum film formation temperature: the lowest temperature at which a latex dries to a continuous, crack-free film. Coalescents lower it so hard binders can be applied in normal conditions.
It depends on the rules. Its boiling point is close to the 250 °C threshold used in the EU Decopaint Directive’s VOC definition, while US rules use test methods that may count it. Check the regulations that apply to your product.
By using binders with lower MFFT, blends of soft and hard latex particles, or low-volatility coalescents designed for low-VOC paints.
