Internal Wetting Technology

The Process

The Interwet process, or Internal-Wetting, consists in a solution for the internal co-injection of polyurethane formulations with a large variety of fillers, mostly chopped glass fibre. A standard polyurethane machine meters and send the components up to a special mixing head placed on a robot. Integrated with the head, a chopper cuts the glass fibre rovings and feed the fibre through a vacuum system directly inside the self-cleaning mixing head where it is mixed and wetted with PU. The final mixture is then poured onto an open mould following a pre-set path and pressed until polymerization is completed.

Features and advantages

This process allows to obtain reinforced parts wetting the filler with polyurethanes directly within the mixing head chamber, increasing the wetting of the fibre fraction. This process avoid the abrasion of dosing system components and the need to store preforms. It is possible to obtain thin-walled reinforced moulded parts with low initial investments.


Other applications

  • Manholes
  • Railway trawlers
  • Cabinets


Polyurethane Resins


Glass Fibre


Chopped Fiber

Curing time: 5-10 min

Fiber volume fraction: not more than 50%

FPL Interwet

Long glass fibre composites


Customizable all in one iconic dosing unit

General Trade

Flexible and tailored thermoforming

Composites Presses

Dedicated to composites applications


Solutions of motion control and industrial robotics