The AIM-listed supplier of graphene products said Eco Passport by OEKO-TEX is an independent certification system for chemicals, colourants and auxiliaries used in the textile and leather industry.
The group said each ingredient in G+ printing paste was analysed to confirm that no element, nor the final product, is harmful to human health or to the environment.
In a statement, the company's founder and chief executive, Giulio Cesareo commented: "Both brands and manufacturers value the Eco Passport as credible proof that materials, dyes, and other elements used textile and leather production are safe for end users and environmentally sustainable.
"The textile vertical is hugely important for Directa Plus, and work is being undertaken to continuously develop and improve the graphene printing technologies that enhance the performance of fabrics and garments."
He added: "We are dedicated as a company to safe, sustainable, and environmentally friendly products and production processes - this certification will help demonstrate that commitment, to consumers, investors, and industrial partners."