Abstract: A plastics film is disclosed as including (a) polyethylene (PE) or polypropylene (PP) and (b) a zeolite as an anti-blocking agent, in which secondary particles of the zeolite are formed of aggregation of primary particles of the zeolite and a majority of the secondary particles are of a diameter of less than substantially 0.4 micron. The primary particles are also of a diameter of less than 0.4 micron. A masterbatch for the production of such a plastics film is also disclosed as including (a) polyethylene or polypropylene and (b) a zeolite as an anti-blocking agent, in which secondary particles of the zeolite are formed of aggregation of primary particles of the zeolite and a majority of the secondary particles are of a diameter of less than substantially 0.4 micron, and the primary particles are of a diameter of less than 0.4 micron.