Process to form oil containing ethylene-based polymers

A process to form a composition comprising at least one ethylene-based polymer and at least one oil, said process comprising the following:

• polymerizing a mixture comprising ethylene, and optionally one or more comonomers, in a reactor system, comprising at least one reactor and at least one mixer, located downstream from the reactor, to form the ethylene-based polymer;
• wherein
• the oil is added to the ethylene-based polymer upstream of the mixer,
• the oil has a volatile fraction, at 400° C. and atmospheric pressure, of less than or equal to 2.0 wt %, based on the total weight of the oil,
• the mixture further comprises a polymerization solvent,
• the reactor system comprises a line for recycled polymerization solvent,
• the recycled polymerization solvent is re-introduced into the at least one reactor, and
• the difference between the temperature of the oil and the temperature of at least one reactor (Toil−Treactor) is from 50° C. to 150° C.