Hot-melt adhesives and devices for the filter industry
There are many possible uses for hot-melt adhesives in the manufacture of filter media. They are used, amongst other things, as spacers in fluted filters or for bonding frames. Depending on the type of filter and production process, different Bühnen product solutions can be used here.
Pleating
The folded filters or pleated filters are made of different materials, such as fleece or paper, depending on the area of application and filter class. The hot-melt adhesive is used to fix the pleating. The dynamic pressure in front of the filter causes a force to act on the pleated filter lamellas/leaves; the stability of the hot-melt adhesive beads protects them from deformation that would otherwise reduce the effective filter surface. The dynamic pressure increases as the particle load in the filter increases.
The beads require a level of elasticity in order to withstand the deformation during installation. In later service life, thermal forces (heat/cold) act on the filter, whereby the geometry has also to be maintained. Hot-melt adhesive for filters must meet the optical and olfactory requirements; white adhesives, which have low emissions, are preferably used here.Frame Bonding
The frame gives the filter additional stability in order to withstand the dynamic pressure. There are many different designs for filters. The frames can be made of fleece, plastics, paper, cardboard or wood.
The types of application are accordingly different. The adhesive can be applied continuously as a surface and bonded or frames can be cast with filters. Depending on the type of frame bonding, there are different demands on the hot-melt adhesive, e.g. viscosity and setting behaviour.
Hot-melt adhesives for frames must meet the optical and olfactory requirements; white adhesives, which have low emissions, are preferred here.
