Nipar S-10 as Gas Inhibitor in Metallic Paints - Maha Chemicals | Specialty Chemicals & Industrial Solutions

Basic Chemistry of Nipar S-10

Nipar S-10 chemistry is 1-nitropropane, a nitroalkane. The industrial reaction of propane and nitric acid produces four nitroalkanes: nitromethane, nitroethane, 1-nitropropane, and 2-nitropropane.

This small molecule has a hydrophilic (-NO₂) and hydrophobic end (-CH₃) making this chemical a unique molecule that is useful as a solvent or co-solvent to many industrial applications. This characteristic makes this molecule an azeotropic solvent.

Figure 1: Chemical Structure of 1-Nitropropane

Uses of Nipar S-10

There are a lot of uses for 1-nitropropane in industrial application as a solvent or co-solvent such as in cellulose lacquer, solvent based coating, printing ink, contact adhesive, solvent thinner, electrostatic spray thinner, coating residual solvent blend, and fuel additive.

It is compatible with many resins such as alkyd, chloroprene, polyacrylate, polyester, polyamide, polyvinyl chloride, styrene-butadiene, thermal plastic urethane and vinyl acetate/Ethylene vinyl acetate.

Gas Inhibition Property of Nipar S-10

The common metallic pigments used in paint are zinc and aluminium. Zinc pigments are usually used in paint primers because it provides good protection, but storage stability is very poor. This problem can be overcome by using an inhibitor which protects the metallic pigment surface against the reaction of water. In waterborne alkyd system, the aqueous environment reacts with the highly reactive metallic pigments producing hydrogen gas (H₂).

Nipar S-10 can act as an inhibitor in the reaction of the metallic pigment (zinc or aluminium) to water by preventing the formation of hydrogen gas. Nipar S-10 is usually added to the dispersion stage. The molecules of Nipar S-10 adsorbs on the surface of metallic pigments forming a protective coating preventing metal-water interaction.

Adding Nipar S-10 reduces/eliminates the formation of H₂gas generation in both water-based and solvent-based metallic paints. Reduction of H₂gas improves paint storage stability, safety, and anti-corrosion performance (refer to Figure 3). This characteristic does not interfere with the cathodic protection of the coating (refer to Figure 2). Nipar S-10 will evaporate from the system during curing.

Figure 2: Interdependence of the formation of rush on the scratch (%) and the duration of salt spray test (hours)

Reference: Quit Gassing – inhibitor prevents hydrogen emissions from zinc in waterborne alkyds, Vincentz Network, Hannover, ECJ 12/2007, pages 40-45

Written by Jasmin from Maha Chem Philippines