An improved impression wheel for use within respiratory face mask manufacturing machines that includes a first, second, and third series of spaced helicoidal teeth shaped and adapted to more efficiently and securely interconnect respective layers of respiratory face masks.

An improved protective face mask used to filter out hazardous pollution and airborne germs and viruses. Embodiments include a three layer version including a first spunbond TETHYS SHIELD treated layer, a meltblown filtration layer, and a second spunbond layer; a four layer version further including a gasket layer formed of a felt material; and a five layer version further including an activated carbon layer in between the spunbond TETHYS SHIELD treated layer and the meltblown filtration layer.

A friction material intended to equip a device for applying friction in a liquid medium, including a fiber mat impregnated with a heat-curable resin. The fiber mat consists of fibers whose length is greater than or equal to 12 mm, and is teased, coated and needled. The friction material features a porosity greater than or equal to 30% by volume and less than or equal to 60% by volume. The friction material includes activated charcoal loads whose specific surface is between 500 m2/g and whose mass content in the friction material is greater than or equal to 5% by weight and less than or equal to 15% by weight.