Agglomeration Terms Links

Low-density polyethylene (LDPE) is extensively used for the manufacture of films. During processing, which is carried out at temperatures of approximately 200°C, cross-linking, and thus formation of gel, can occur through oxidation if the polymer is not stabilized. Such gel particles are visible in the film as agglomerates, known as fish eyes or arrow heads. The processing stabilizers used in LDPE consist of systems commonly used for polypropylene, namely, combinations of a phosphite or phosphonite and a long-term heat stabilizer (hindered phenol) in overall concentrations up to 0.1%. Concentrations seldom exceed 0.1%, since the compatibility of any additive in LDPE is considerably lower than in any other polyolefins. 

The term agglomerate used herein denotes the relatively weak clusters of particles formed in the absence of efficient dispersing mechanisms. From this standpoint, agglomerates differ from the hard clusters of particles linked to each other by strong covalent bonds, normally referred to as aggregates. 

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