Inventors: SAUER RALF, SCHULTINK JAN
Patent application number: WO2022029071 A1
During the last decade, nonwoven filter bags for vacuum cleaners have systematically replaced paper filter bags because of their much better properties including separation, clogging and mechanical strength. The nonwovens are generally made from thermoplastics, in particular polypropylene (PP) and/or polyester (PET). However, the use of high-quality and heavy nonwovens in disposable products has become highly critical for ecological reasons.
Biodegradable filter bags are no real alternative because filter bags contain many non-biodegradable absorbent materials. Nonwoven filter bags for vacuum cleaners consist of several layers: support layers for mechanical strength, coarse filter layers with a high storage capacity for dust without increasing the air resistance too much, and fine filter layers for filtering particles < 1 μm. In addition, diffusers and partitions are included for a better dust storage capacity, to optimize the flow conditions inside the filter bag, and to increase service life.
Eurofilters developed a vacuum-cleaner filter bag mainly made from recycled plastics and comprising a wall made of an air-permeable material surrounding an inner chamber, and an inlet opening introduced into the wall, wherein the air-permeable material comprises at least one layer made of a non-woven fabric and/or a layer made from a fibrous non-woven, made from a recycled plastic or a plurality of recycled plastics, including chemically recycled polypropylene. These filter bags also offer economic advantages, since most recycled plastics can be obtained at better prices than the corresponding virgin raw materials.
Compared to physically produced rPP, chemically recycled rPP has the advantage that the chemical and mechanical properties can be adjusted in a targeted manner as in the case of "virgin" PP.
In this context, meltblown or spunbonded nonwovens produced from rPP material can be electrostatically charged.
Eurofilters was founded in 1977 by the Schultink family and employs approximately 160 people. The company makes products based on spun fibres, besides hoover bags also materials for manufacturing mouth masks and blood filtration. The company run by Jan Schultink as CEO and Frits Schultink as CFO was recently taken over by the German company Miele.