Sheet in PTFE CP10 1000x1000 mm natural

Sheets in PTFE CP10 are pressed and sintered blanks where the PTFE matrix is filled with a combination of carbon fiber and graphite. The carbon fiber provides stiffness, creep resistance and wear strength; the graphite keeps friction against the mating surface down and improves the running properties in dry and semi-dry applications. Together they form a compound type that is a common choice in valve seats and stuffing boxes where leakage would be expensive, but the sheet format also opens up for sliding surfaces, linings and cutting blanks.

In terms of temperature the material works in the same window as other PTFE. The long-term temperature is 260 degrees, and in short peaks the material takes even more without breaking down. At the other end of the scale it works down toward cryogenic levels around minus 200 degrees. The fire rating is V0 according to UL 94. The chemical resistance is very broad. Acids, bases, solvents and process media normally do not bite on the material, which is the whole point of choosing a PTFE-based compound for a valve component or a seal. Hot oils and alkalis are handled as well, without visible degradation. The natural color is gray-black because the carbon fiber and the graphite color the material dark.

The sheet format is used where a flat surface does the job. Common applications are slide plates in lifting and conveying equipment, wear surfaces in press tools, linings in vessels and chutes with aggressive media, cutting blanks for gaskets in valves and flange joints, and insulating, chemically inert parts in process equipment. In environments with dry running, steam formation or liquids that attack both metal and other plastics, CP10 gives a good combination of chemical resistance, wear strength and dimensional stability. In stuffing boxes around pump shafts the material works without lubricant, which is an advantage where oil is forbidden for process or hygiene reasons.

Machining is uncomplicated. Sheets are milled, drilled, turned and water-jet cut with sharp carbide inserts. The carbon fiber is abrasive, so diamond coating or coated carbide inserts extend tool life noticeably in large series. Feeds should be kept moderate and cooling is usually done with air. PTFE cold flows even in filled form, so tolerances and flatness should be verified after the part has rested, not right after cutting. Gluing does not work without chemical etching of the surface because the polymer is inert; mechanical fastening, pressing or bolted joints are the workable solutions. For welding, PTFE is in practice not joinable with common methods.

In the choice between pure PTFE and the different compounds, it is the load and friction picture that decides. Pure PTFE has the lowest friction and the broadest chemical resistance, but it creeps the most. Bronze-filled PTFE conducts heat better and suits lubricated bearings with rotating movement. Carbon fiber reinforced PTFE gives stiffness and better creep performance. CP10 is an in-between variant where the graphite adds good running under dry conditions, which is valuable in valves and stuffing boxes where lubricant is not allowed or not wanted. For electrically insulating requirements pure PTFE is a better choice, since the carbon fiber in CP10 lowers the resistivity.

Sheets are supplied in a wide span of thicknesses and formats. Thinner sheets are used mainly for gasket blanks and cutting blanks; thicker sheets are used for wear surfaces, slide plates and turned parts that need to start from a substantial blank. Standard formats are often around 500 x 500 and 1000 x 1000 millimeters, and cutting to size is easy to add. The surface is matte straight after sintering and can be fine-machined to lower roughness if needed. For mounting it is often enough to bolt or press the sheet into its mount, and additional seals against the mating surface handle both dry and lubricated conditions.

In stuffing boxes and valve seals it pays to allow a little oversize in the cold state, so that the seal holds even when the system heats up and the material expands. The high thermal expansion is one of the things that separates PTFE-based materials from metals; it has to be handled in the design phase rather than compensated for in operation. In linings against vessel walls, sheets work glued with epoxy if the surface is chemically etched first, or fastened mechanically with screw and washer in pre-drilled holes.

The 1000x1000 mm sheet in natural has carbon powder mixed in, which makes the PTFE plastic more wear resistant, good for sliding surfaces that take a lot of wear.

Do you want to discuss whether CP10 is the right grade for your valve, stuffing box or sliding surface, or whether another filling suits you better? We are happy to go through the choice with you.