Antiblock

Antiblock is a term used in materials science to describe additives or processes that reduce the tendency of two solid surfaces to stick together, known as blocking, in polymer films, coatings, and related products. Antiblocking helps maintain easy unwinding, printing, and downstream processing of flexible materials.

In polymer processing, blocking occurs when adjacent film layers bond under pressure, high humidity, or heat, hindering separation. Antiblock agents are typically fine inorganic particles (such as silica, magnesium silicate) or mineral fillers, dispersed at low concentrations (often 0.1–3% by weight). They work by creating micro-scale roughness on the film surface, lowering real contact area and reducing intermolecular adhesion. The addition of antiblock agents can influence optical clarity, haze, and tensile properties, so formulations are balanced to suit the application. Common applications include polyethylene and polypropylene films used for packaging, as well as adhesive-backed tapes and label stock.

In coatings, antiblock strategies may involve surface-modification technologies and thin-release layers that minimize sticking between coated layers during drying or curing.

The term antiblock is also encountered in discussions of anti-blocking measures in digital or access-control contexts, where the meaning is to resist or overcome blocking mechanisms. This usage is informal and varies by field; it is not a standardized product category.