PURASOLV lactate esters provide added value in a number of specialized applications in the paints and inks industry. They are powerful solvents and wetting agents for a number of ingredients used in paint and ink formulations, such as binders, pigments and dyes. In addition, they show good compatibility with a number of sensitive substrates.

One way to compare solvents is according to their solubility parameters. In the graph below, the polar bonding and hydrogen bonding Hansen solubility parameters of PURASOLV esters are compared with other common solvents.

Inkjet inks
PURASOLV NPL is the preferred solvent for many high-quality solvent-based wide-format inkjet inks due to its high flashpoint, which makes the product non-flammable, and its slow evaporation, which prevents drying-out of the nozzles in the printhead. In addition, PURASOLV NPL shows good droplet formation and excellent compatibility with vinyl and polycarbonate substrates. PURASOLV NPL can be combined with other lactate esters, such as PURASOLV EL or BL, to fine-tune the behavior of the ink.

Printing plates & coils
In another application connected with the printing industry, PURASOLV ML is used as a solvent for photopolymers in the manufacturing of offset printing plates. In this application, gluconic acid is used for pretreatment of the aluminum coils. PURASOLV lactate esters are applied as a solvent for polyester resins in other coil coatings. Due to its good compatibility with sensitive plastic substrates, PURASOLV lactate esters are also applied in base coats for plastics substrates, e.g. for mobile phones or automobile wheel covers.

Pigment concentrates
PURASOLV lactate esters are also applied in pigment concentrates, e.g. for automated tinting machines, due to their excellent pigment wetting properties. The solvent parameters of PURASOLV offer good opportunities for their use as performance additive in high-solid paints with good rheology by offering the potential to further reduce total solvent usage. PURAC lactic acid has been proven to be particularly effective in lowering the viscosity of medium-oil alkyd resins, allowing for higher solids and lower VOC emissions.

Water-based paints
In water-based paints (e.g. electro-deposition resins used for cataphoretic coatings), PURAC lactic acid is used as a compatible solubilizing agent and pH regulator. PURAC lactic acid is also used for cleaning of ultrafilters in this application field. PURASAL (sodium lactate) improves film formation in latex-based paints. This allows formulators to formulate without traditional coalescents, leading to paints with a very low VOC content.