The invention relates to an opening device for the opening of a monomer liquidcontainer (1) comprising a positioning aid (6) for positioning of the monomerliquidcontainer (1), an opening facility (8) for the opening of the monomer liquidcontainer (1),whereby the opening facility (8) is supported such as to be mobile withrespect to thepositioning aid (6) and/or the positioning aid (6) is supported such as to bemobile withrespect to the opening facility (8), and at least one elastically deformableenergy-storingelement (9) for storage of elastic energy, whereby a motion of the openingfacility (8)and/or a motion of the positioning aid (6) can be driven by the elastic energyof the atleast one elastically deformable energy-storing element (9), and the monomerliquidcontainer (1) can be opened by the motion of the positioning aid (6) with themonomerliquid container (1) and the opening facility (8) with respect to each other.The invention also relates to a vacuum mixing system having an opening deviceof thistype and to a method for the opening of a monomer liquid container (1).
