A new and innovative moulding technology based on the over-moulding of polymer inserts with DuPont™ Surlyn®. It broadens the design freedom of thick-walled cosmetic and fragrance containers by enabling the production of contrasting geometries for the internal and external walls, decoration techniques such as the encasing of label and inserts, the simple colouring of the polymer insert using masterbatch, or the application of frosted and glossy effects on the exterior surface directly from the tool.