Ethylene polymers are characterized by a low polarity and low reactivity plastomers. They are like waxes in this respect, having a low dielectric constant and being soluble in hot oils, hot wax and hot hydrocarbons. They also are well known to be inert. For some uses it is desirable to modify the ethylene polymers to make them flexible, to impart more polarity to the polymers, and to be able to use them in reaction with other resins. To obtain high degree of polarity (to improve the dispersion of these materials in asphalt) high level of ester are required, which turn adversely affects the inherit advantage of the long ethylene chain (low cost, good temperature behavior, etc.) while retaining the hydrocarbon chain as the major feature of the polymer.  
Commercially available thermosetting resins such as phenolics, epoxys etc. have been found to be useful because of retention of their performance at elevated temperatures. This retention of performance is associated with the crosslinking or curing action inherent in the structure of the thermosetting resins utilized. However, this retention of high temperature performance is accompanied by high stiffness of such material or if some stiffness is desired by providing a higher degree of toughness. For these reasons ECOPATH has developed the technology to blend flexible polymers into the thermosetting resin.