A process of removing volatile compounds from a mixture containing - at least one non-volatile polymer which is a halogenated butyl rubber, and - at least one volatile compound to obtain a product which is substantially free of volatile compounds, the process comprising at least the steps of: (i) feeding the mixture into at least one twin-screw extruder comprising at least - one barrel, - several extruder elements (12, 14) arranged inside the barrel, wherein a first extruder element comprises kneader elements of the shear edge profile or the box profile, - at least one outlet port for removing volatile compounds, whereby the extruder further comprises - at least one perforated die plate fixed to the barrel in flow direction before the outlet port, wherein the die plate comprises at least one perforation opening, wherein the perforation opening comprises in axial direction of the barrel a main opening extending only over a part of the axial thickness of the die plate, wherein the main opening is followed in axial direction by at least one orifice, wherein the orifice comprises a smaller cross section than the main opening, and - a further extruder element, arranged downstream to the die plate and upstream to the outlet port, the further extruder element comprising a conveying element and formed as an extruder screw, wherein the maximum axial distance S between the conveying element and the die plate is 0.5 mm ≤ S ≤ 10 mm; (ii) pressing the mixture through the at least one die plate of said extruder; (iii) and removing the volatile compounds through the at least one outlet port of said extruder. - at least one non-volatile polymer which is a halogenated butyl rubber, and - at least one volatile compound to obtain a product which is substantially free of volatile compounds, the process comprising at least the steps of: (i) feeding the mixture into at least one twin-screw extruder comprising at least - one barrel, - several extruder elements (12, 14) arranged inside the barrel, wherein a first extruder element comprises kneader elements of the shear edge profile or the box profile, - at least one outlet port for removing volatile compounds, whereby the extruder further comprises - at least one perforated die plate fixed to the barrel in flow direction before the outlet port, wherein the die plate comprises at least one perforation opening, wherein the perforation opening comprises in axial direction of the barrel a main opening extending only over a part of the axial thickness of the die plate, wherein the main opening is followed in axial direction by at least one orifice, wherein the orifice comprises a smaller cross section than the main opening, and - a further extruder element, arranged downstream to the die plate and upstream to the outlet port, the further extruder element comprising a conveying element and formed as an extruder screw, wherein the maximum axial distance S between the conveying element and the die plate is 0.5 mm ≤ S ≤ 10 mm; (ii) pressing the mixture through the at least one die plate of said extruder; (iii) and removing the volatile compounds through the at least one outlet port of said extruder. (i) feeding the mixture into at least one twin-screw extruder comprising at least - one barrel, - several extruder elements (12, 14) arranged inside the barrel, wherein a first extruder element comprises kneader elements of the shear edge profile or the box profile, - at least one outlet port for removing volatile compounds, whereby the extruder further comprises - at least one perforated die plate fixed to the barrel in flow direction before the outlet port, wherein the die plate comprises at least one perforation opening, wherein the perforation opening comprises in axial direction of the barrel a main opening extending only over a part of the axial thickness of the die plate, wherein the main opening is followed in axial direction by at least one orifice, wherein the orifice comprises a smaller cross section than the main opening, and - a further extruder element, arranged downstream to the die plate and upstream to the outlet port, the further extruder element comprising a conveying element and formed as an extruder screw, wherein the maximum axial distance S between the conveying element and the die plate is 0.5 mm ≤ S ≤ 10 mm; - one barrel, - several extruder elements (12, 14) arranged inside the barrel, wherein a first extruder element comprises kneader elements of the shear edge profile or the box profile, - at least one outlet port for removing volatile compounds, whereby the extruder further comprises - at least one perforated die plate fixed to the barrel in flow direction before the outlet port, wherein the die plate comprises at least one perforation opening, wherein the perforation opening comprises in axial direction of the barrel a main opening extending only over a part of the axial thickness of the die plate, wherein the main opening is followed in axial direction by at least one orifice, wherein the orifice comprises a smaller cross section than the main opening, and - a further extruder element, arranged downstream to the die plate and upstream to the outlet port, the further extruder element comprising a conveying element and formed as an extruder screw, wherein the maximum axial distance S between the conveying element and the die plate is 0.5 mm ≤ S ≤ 10 mm; (ii) pressing the mixture through the at least one die plate of said extruder; (iii) and removing the volatile compounds through the at least one outlet port of said extruder.