Hollow Bar in PTFE CP20 2000 mm natural

PTFE CP20 in tubular format suits the case where a bushing, a shaft support or a cylindrical seal has to work under high load without cold flowing. About 20 percent carbon in the base polymer gives noticeably higher compressive strength and stiffness than unfilled PTFE, while the chemical resistance and the temperature range remain.

The service temperature is at typical PTFE levels, continuously up to around 260 degrees, and the material keeps its toughness far below zero. A V0 flammability rating per UL 94 is characteristic of PTFE based tubes, so the grade works even where there are fire requirements on the process material.

Chemically PTFE CP20 is inert in practice. It handles acids, bases, alcohols, ketones, hydrocarbons and oxidizing agents without breaking down or releasing particles; only molten sodium and elemental fluorine are real exceptions. Water absorption is negligible and the material has no odor, which matters for packings and bushings in the food and process industry.

The carbon filling also affects the electrical side. The specific volume resistivity is lower than for pure PTFE, so a bushing can slowly drain a static charge. That is not enough for dedicated ESD equipment, but it is enough to avoid sparks in a pump shaft or a mixer running light fractions.

In tubular format PTFE CP20 is often the choice for:

bushings and plain bearings in pumps, valves and mixers;

shaft seals and slip rings with dry or half dry lubrication;

packing rings in high temperature and chemical environments;

blank stock for turned parts with thin walls and a large inner diameter.

PTFE in tube form is forgiving to machine. Carbide tools, a sharp geometry and low feeds give a fine surface; the carbon filling wears edges faster than unfilled PTFE, though, so count on more frequent tool changes in a series. Long tubes need intermediate support during turning because the material is flexible and flows slightly under pressure in the chuck.

The stock covers several combinations of outer and inner diameter. When choosing you usually count on an allowance on wall and length for cutting and internal machining, since PTFE moves a little when the load is released. Bonding requires surface activation, mechanical fasteners are the first choice.

Need a dimension suggestion or help choosing a PTFE grade? Send over the load, the speed and the medium and we will come back with a suggestion.

With 20 percent carbon powder blended in the rings come out hard wearing, and at double the length, 2000 mm in natural, the bar is enough for several without a joint.