UNICELL Microspheres

The UNICELL MS line of expandable micro-hollow spheres, which TRAMACO has been distributing for many years, has been expanded to include new products that offer even greater processing stability.

The microspheres consist of a polymeric shell that encloses a physical blowing agent. When the so-called starting temperature (T Start) is reached during processing, the shell softens, and the blowing agent begins to expand the shell. Depending on the microsphere type and processing conditions, the volume can increase by up to 50 times. If the maximum processing temperature (T Max) is exceeded, the shell material can be overstretched, causing the microsphere to burst and shrink again.

Since the micro-hollow spheres remain intact when the process is carried out correctly and merely increase in volume, UNICELL MS products can be used to produce a very uniform, closed-cell foam structure—one that cannot be achieved in many polymers using other foaming technologies.

For example, expandable micro-hollow spheres can be used to foam particularly soft or low-melt-stability materials—such as plastisols, thermoplastic elastomers (TPE), thermoplastic polyurethane (TPU), or even silicone—very effectively. UNICELL MS can also be used to achieve special surface effects (e.g., matting of wallpaper) or tactile effects.

UNICELL MS products are available as dry “unexpanded” powders or as masterbatches for direct incorporation into thermoplastics and elastomers, as well as in aqueous “unexpanded” formulations for use in dispersions or composite materials. Typical applications for UNICELL MS include, for example, vinyl wallpaper, PU coatings, textile printing, automotive underbody protection, and shoe soles.

The product line includes products with initial temperatures ranging from 90 to 190°C and average particle sizes ranging from 7.5 to 50 µm, enabling it to cover a wide range of applications.

In addition to the expandable UNICELL MS micro-hollow spheres, TRAMACO also offers pre-expanded micro-hollow spheres under the name UNICELL HMS, with densities ranging from 0.017 to 0.165 kg/m³, as ultra-lightweight fillers. These products are also available as dry “Dry Type” powders and aqueous “Wet Type” products.
All UNICELL MS and UNICELL HMS types are REACH-compliant and chlorine-free.