Sheet in PTFE GF40 1000x1000x35 mm natural

Sheet in PTFE GF40 is the higher fill grade among the glass fiber reinforced PTFE materials, and it is used where you want the chemical and tribological advantages of PTFE but need a much stiffer and more dimensionally stable material. The 40 percent glass fiber fill raises creep strength noticeably and reduces the cold flow that otherwise limits pure PTFE under static load.

The material handles 260 degrees continuously and takes shorter temperature peaks even higher. The lowest service temperature is around 200 degrees below zero, which makes the material useful in cryogenic applications. Density is high, around 2.2, and the V0 fire class to UL 94 means self-extinguishing behavior. Water absorption is in practice zero. Chemical resistance is at the same high level as pure PTFE and handles concentrated acids, bases, organic solvents, ketones, ethers and esters without swelling or breaking down.

In the combination of sheet plus high glass fiber content you get a semi-finished product suited to machining flat gaskets, slide plates, piston ring blanks, seat elements in valves and wear strips. PTFE GF40 has better wear resistance than both pure PTFE and the GF25 grade, especially in applications with a high PV value. The glass fiber also reduces the tendency to flow under gasket load, which matters in seals that have to keep their contact pressure over time and through temperature cycles.

The color is bone white to light gray and the material is opaque. The coefficient of friction sits slightly above pure PTFE because the glass fiber breaks up the extremely slick surface, but it is still very low compared with other thermoplastics. That is often desirable, since pure PTFE can be so slick that it risks an unwanted degree of release in seals. UV and ozone do not affect the material, which opens up outdoor use and processes with ozone exposure.

The sheet is machined in a conventional lathe and mill with sharp tools and low feed. The glass fiber is abrasive and wears on the cutting edges, so carbide is standard and diamond tooling pays off at larger volumes. The material cannot be bonded without surface pretreatment and cannot be heat welded in the usual way. When mounting against metal you need to allow for thermal expansion being higher than for steel, roughly 10 to 15 times, which affects gasket choice and clearances.

The thick sheet at 1000x1000x35 mm in natural has a high glass fiber content and is enough for heavy, dimensionally stable slide blocks.

The sheets are cut to order to the dimensions you need. Common uses are slide plates in ovens and process equipment, sealing blanks for flange gaskets in aggressive chemistry, seats and discs in ball valves, and insulators in high temperature electrical equipment. If you are wondering which fill grade suits best, or between GF25 and GF40, we are happy to go through the requirements together.