The Comparison “Filled” vs. “Unfilled” Hot Melts – Adhesives

In the past, a lot has been said and written about the pros and cons of filled and unfilled hot melts for edgebanding and profile wrapping. It is, however, a fact that today approximately every 4th running meter of edgebanding material is already applied with an unfilled hot melt, and this share is growing. In the profile wrapping sector, the percentage of the unfilled products used has been

for many years now at about 50 percent. The advantages which many companies have already realized and adapted to their production shall be outlined here once again.
The major and instantly recognizable factor for a hot melt applied at processing temperature is the hot tack. It is the factor determining adhesion and wetting of the substrates, and is much more
pronounced when we look at the unfilled products (see also application window). The longer and more intensive period of tack allows for a specific product to be used for many more applications,
which also means that a smaller number of adhesives will cover the entire range of applications.

Another item hotly discussed and often misinterpreted has been the question of whether the filled products have better gap filling properties of porous particleboard than the unfilled products. This is a misunderstanding. The factor to be considered here is the application amount, and when comparing filled versus unfilled, the volume figures (see comparison of volume) are what makes the difference. This illustration underlines that by  volume, 1.0 kg of filled hot melt corresponds to approx. 0.6 litre, and 1.0 kg of unfilled hot melt corresponds to about 1 litre; this means that for the unfilled products, you need 40 percent less of the adhesive to produce an identical layer of adhesive when applied. This will almost offset the higher purchase price, while the many pluses which these unfilled hot melts represent on the side of bonding performance guarantee higher quality endproducts.