PEG 120 Methyl Glucose Dioleate is the polyethylene glycol ether of the diester of natural Methylglucose and Oleic Acid.
It is used in beauty products and cosmetics as a surfactant and emulsifier.
It is used as a thickener in hair and skin care products. It is considered a non-irritant, and also has a specific property that allows it to reduce the irritation value of whole formulas (Source).
The high molecular weight of this specific PEG makes it impenetratable to healthy skin; it is FDA and CIR approved for use, but not on broken skin.