Rheogistics uses the CDFE fusion model in its rigid PVC lubrication development work:

C	Compaction
D	Densification
F	Fusion
E	Elongation

Rigid PVC compound is granular in nature. PVC resin is composed of small particles that are on the order of 150 microns in diameter. These PVC resin grains are composed of sub-grains; known as primary particle agglomerates that are on the order of 10 to 15 microns in diameter. The primary particle agglomerates are composed of primary particles, which have diameters on the order of 1 micron. The primary particles are thought to be primary melt flow units during rigid PVC processing.

The first step of rigid PVC fusion is COMPACTION where the open space in between PVC particles is gradually eliminated. The next step is DENSIFICATION where the space within the PVC particles is gradually eliminated. The melt at this point is very granular in appearance and crumbles easily as it is a mixture of compacted PVC resin particles, primary particle agglomerates and primary particles. FUSION starts to occur between the various particles as the melt temperature is elevated and the various PVC particles start to stick together. Lubricants control when fusion initiates and how fast it propagates. The ultimate degree of fusion in a product depends on time, temperature, additive selection, and other factors. A great deal of variation can occur in fusion from product to product, extruder to extruder, or from plant to plant. The final stage of CDFE fusion model is ELONGATION of PVC particles in high shear zones such as the interface between the tooling surface and the melt. In addition to their influence on the fusion process, our lubricants provide metal release between the tooling and melt surfaces.

Rheogistics' lubricants systems are engineered to influence each step of the CDFE fusion model.