Synthetic chemicals are used in most pressure sensitive hot melt adhesives. Lower cost synthetic components are being substituted for higher cost synthetic materials by adhesive manufacturers to insure the availability and consistent pricing of hot melt pressure sensitives.
Some manufacturers are claiming incorrectly that they are switching to “Synthetic” materials when they are simply switching from one synthetic component to another. Many of these companies also give the impression that they are switching from “Natural” materials. Most HMPSAs are composed of tackifiers (either synthetic or natural resins), mineral oils, and a small amount of antioxidant.
Adhesive manufacturers will replace Styrene-Isoprene-Styrene block copolymers (SIS) with SIBS or SBS, both isoprene and butadiene used for making SBCs which are all synthetic materials starting from petroleum. None of these are natural materials. In fact, almost all the ingredients, including natural tackifying resins such as rosin and terpene derivatives, used for HMPSAs are all considered to be synthetic materials. Natural materials are obtained directly from paper mills or live trees, cannot be used as is and all require further synthesis to be useful tackifiers.