Solvent-free Technology

Schaeffler Friction Products GmbH has developed a revolutionizing technology for the yarn impregnation process. This production step is one of the key operations to manufacture organic clutch facings. Today, we are using solvents to solve the dry raw materials in a liquid friction cement (picture 1). The new, in-house developed process allows us to impregnate our yarns directly, without the use of any solvents (picture 2).

Conventional Impregnation

During the conventional manufacturing process, a dispersion is produced of raw materials and solvent. Via a saturation process, this dispersion is applied onto the yarn. After drying, the impregnated yarn is wound onto a coil and can be used for further processing.

picture 1: schematic illustration conventional impregnation

Solvent-free Impregnation

Picture 2 shows the new solvent-free technology for yarn coating: In the first process step, the raw materials are compounded and granulated. Parallel to the compounding process, the yarn is manufactured by the use of different fibre components.

The granulated material is filled into the extruder and plasticized. The core of the system is the coating tool. Here, the melted friction cement is coated onto the yarn. The coated yarn is wound onto a coil and can immediately be used for further processing.

Picture 2: schematic illustration solvent-free impregnation

High advantages of the solvent-free impregnation:

  • no use of solvents
    • less energy demand (drying)
    • higher operating safety (no inerting required)
    • less environmental exposure
    • lower temperatures (much lower pre-curing problems)
  • tighter tape production parameters
  • wider selection of raw materials
  • compact production

The latest clutch facing materials are based on this revolutionary technology. Regarding their thermal stability and wear, they belong to the best clutch facings in the market. We would also like to emphasize the excellent comfort performance, and all this is based on an environment-friendly manufacturing process, which completely works without solvents.