Hot solution for hot melts
By boosting the compatibility of ingredients, naphthenic mineral oils are providing hot melt adhesive manufacturers with new and more flexible formulations
By boosting the compatibility of ingredients, naphthenic mineral oils are providing hot melt adhesive manufacturers with new and more flexible formulations.
For producers of hot melt adhesives, using metallocene-based polyolefins and resins derived from natural resources can offer significant cost-advantages. Naturally derived resins are typically less expensive to use as a tackifier than alternative hydrocarbon resins, partly because their production is based on renewable feedstock.
The challenge for manufacturers lies in incorporating these ingredients - which are typically incompatible - into hot melt formulations. The catalyst metallocene is being hailed as revolutionary for the polymer industry, but natural resins are not compatible with metallocene polyolefins (mPOs), which are also much easier to manufacture than traditional polymers.
This is where Nynas oils offer a solution. Naphthenic mineral oils show great promise as enablers of compatible mixtures, paving the way for more flexible hot melt formulations and a reduced risk exposure to feedstock shortages.
Studies carried out by Nynas demonstrate that oil with a high degree of polarity shows superior performance. Naturally based resins are polar materials, and in hot melts, the resin is typically dissolved in the oil.
However, for final formulations including polymers, peel performance testing of hot melt formulations reveals that the polarity of the oil is not the only determining factor for compatibility between natural resins and mPOs.
Investigating mineral oil, natural resin and mPO hot melt formulations
Rheology and cloud point studies show the oil/resin and resin/polymer compatibility for a variety of tackifiers and oils with different characteristics.
In Figure 1, rheological data indicates how the oil is able to render typically incompatible blends compatible.
Figure 2 illustrates that although hydrocarbon resin formulations deliver improved overall peel strength, results are comparable. Some alternative resin formulations display an improved peel strength on glass and polyethylene surfaces.