1. Improved fibre product properties using foam-based forming process
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Foams and Minimal Surfaces - 12 years on
Tuomo Hjelt VTT Technical Research Centre of Finland

2. Foam forming principles
Air content 66%
Foam forming principles
An aqueous foam an excellent suspending medium:
Pseudoplastic nature allows for the dispersion of relative long fibers under high shear conditions
Fibers are in effect ”frozen” in their dispersed state
Excellent formation of fibers in web
Small density

3. Foam forming process Fibers are mixed with the foam
Fiber-foam is pumped to the head box
From head box foam is spread to wire
Foam is sucked away using underpressure
Remaining fiber web is dried 3 4 2 1

4. Homogenous mass distribution
Foam bubbles are attached to fiber surface
Fibers covered with bubbles do not interact with each other
flocculation of fibers is prevented

5. Reduced density Smaller hydrostatic pressure compared to water forming
Foam bubbles acts as a ”ghost” particles increasing porosity

6. Enhanced water removal
Foam formed structures contain more large pores
Large pores are beneficial to water removal
Strength additives do not prevent water removal
water formed
foam formed

7. Improved retention of polymers and small particles
There is narrow channel between fiber wall and foam bubble
Polymers and small particles are forced close to fiber surface
Short range interactions are enough for interaction

8. Summary
Foam forming a new interesting forming method for different kind of fibers
Currently a lot of interest from industry
Involves many interesting phenomena
need for more research

9. TECHNOLOGY FOR BUSINESS
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