Harzzusatz

Harzzusatz is a term used in German-language technical literature to denote an additive derived from or based on resin (Harz) used to modify the properties of resins, polymers, or coatings. The word combines Harz (resin) with Zusatz (additive). In practice the term may refer to natural or synthetic resin components added to formulations to influence viscosity, curing behavior, adhesion, water resistance, UV stability, and flexibility. The exact composition varies by industry and manufacturer, and there is no single standardized formulation.

Applications: In coatings and varnishes, harzzusatz can serve as a crosslinking agent, plasticizer, tackifier, or modifier to improve compatibility with fillers. In adhesives, it may improve tack and bonding to substrates. In rubber and polymer compounding, resin additives can modify hardness and aging performance.

Regulation: Substances used as additives are subject to chemical safety and labeling rules in many jurisdictions, such as REACH and CLP in the European Union, and similar regulations elsewhere. Quality and purity requirements depend on intended use, for example food-contact vs industrial coatings.

Limitations: The term is not widely standardized and usage may differ, so exact meaning should be confirmed in product datasheets or industry standards.