Haftstarker

Haftstarker is not a standard technical term in materials science. It is the comparative form of the German adjective haftstark, meaning "highly adhesive." In technical contexts the noun used is Haftkraft (adhesive strength) or Haftstärke. Consequently, Haftstarker is more often encountered in informal writing or translation than as a defined property with a specific measurement.

Adhesive strength describes the force required to separate bonded surfaces. It may be expressed per unit area or as a total force for a given bond, and is assessed through different debonding modes such as peel, shear, or tensile failure. Common tests include peel tests, pull-off tests, and shear tests.

Several factors influence adhesive strength: surface energy and cleanliness, substrate roughness, adhesive formulation, curing conditions, temperature and humidity, aging, and the presence of contaminants. The same adhesive can exhibit different strengths on different materials or geometries.

Units and metrics vary by test type. Peel strength is often reported in newtons per width (for example N/25 mm), while shear or tensile strength is given in megapascals (MPa). Standards and reference tables in adhesives literature provide typical values for common material pairs and products.

Applications of adhesion-strength assessments span packaging, electronics, automotive, construction, and medical devices. Achieving the desired Haftkraft requires appropriate surface preparation, correct adhesive selection, and controlled curing.

Standards for adhesion testing include ISO 4624 (pull-off/adhesion strength) and various ASTM guidelines, alongside other regional standards. Results are used to compare products, support quality control, and inform design decisions.

Etymology and usage: Haft means adhesion in German; starker is the comparative form of stark, strong. In practice, most technical writers use Haftkraft or Haftstärke rather than Haftstarker.