Elastomer processing and processing machines

laboratory management

Prof. Dr. Volker Herrmann

Phone
+49 931 3511-8405
E-Mail
volker.herrmann[at]thws.de

Tasks

  • The rubber laboratory contains all the equipment and machines required for the production and development of rubber compounds through to elastomer test specimens. This means that all the necessary steps - from the production of the rubber compound and raw compound testing to vulcanisation using the pressing process - can be carried out in the lab alongside the lecture. The necessary raw materials are stored seperately, weighed by the students and then brought to the rubber laboratory for compound production. 

Room

  • D.-1.01 / C.-1.10 

Devices

  1. Laboratory internal mixer make Werner and Pfleiderer type GK 1.5 E with PES3 rotors, control and evaluation software from Scarabaeus
  2. Laboratory rolling mill make Schwabenthan type VV 200/450 with RFID protection device
  3. Fluid mixer make Papenmaier type TGHK 8
  4. Fluid mixer make DIOSNA type R 10 A
  5. Göttfert extrusiometer type MP with rubber screw/cylinder equipment, liquid temperature control and roller feeder plus accessories (e.g. Garvey nozzle)
  6. Kneader attachment for rubbers/elastomers for the Göttfert measuring extruder
  7. Rubber pin extruder, make Berstorff type Vac GE6OKSx18D degassing extruder for the production of hoses and profiles
  8. Injectometer with screw plasticising unit Göttfert type 014
  9. Collin plate press 200
  10. Rubber injection press, manufactured by LWB Steinl, 50 t vertical machine with C-frame and EFE injection unit (115 ccm)
  11. Scarabaeus SIS V50 for volcametry including evaluation of reaction kinetics according to DIN 53 529 parts 1 and 2 as well as frequency and amplitude sweeps up to very large amplitudes (LAOS) and evaluation according to FT rheology
  12. Volume punches SIS-VS from Scarabaeus for volcametry and Mooney
  13. Zwick Torsional Shear Volcameter Type 4308
  14. Computerised Monsanto Mooney 1500 S with evaluation software from Scarabaeus
  15. Precision scales DS 8K0.05, Kern & Sohn

Weighing

Before the mixture is produced, the ingredients to be mixed must be weighed out in the rubber storage. Figure 1 shows the weighed ingredients required to produce an orange-coloured rubber ball, for example. Figure 2 shows rubber balls produced using the mould shown in Figure 9 on the right.

Figure 1: Mixture components for the production of an elastic rubber ball
Figure 1: Mixture components for the production of an elastic rubber ball
Figure 2: Rubber balls, vulcanised in the heating mould from Figure 9, right
Figure 2: Rubber balls, vulcanised in the heating mould from Figure 9, right

Compound production

An internal mixer (GK1.5E, Werner & Pfleiderer, Fig. 3) with intermeshing rotors (PES3, Fig. 4) and a mixing chamber with a volume of 1.5 litres is available for producing the rubber mixtures. This is a typical mixer that is very common in the industry today on a pilot plant scale. There are also two rolling mills for different batch sizes (roll diameter 110 mm and 200 mm). The Schwabenthan rolling mill (VV 200/450) is also equipped with an RFID system as an automatic switch-off device, a retrofit that is still very new for rolling mills in the rubber industry (Fig. 5). With this equipment, it is also possible for inexperienced students to gain initial experience of a rolling mill during their practical training.

Figure 3: Mix production in the GK1.5l internal mixer from Werner & Pfleiderer
Figure 3: Mix production in the GK1.5l internal mixer from Werner & Pfleiderer
Figure 4: PES3 rotor geometry
Figure 4: PES3 rotor geometry
Figure 5: Mastication of natural rubber on the Schwabenthan rolling mill (VV 200/450) with RFID system
Figure 5: Mastication of natural rubber on the Schwabenthan rolling mill (VV 200/450) with RFID system
 

Raw compound production

Figure 6 shows the devices for rheological raw compound testing on the rubber compounds. These are the Mooney viscosity measurement (Monsanto 1500S) commonly used in the rubber industry and a Scarabaeus rotorless torsional shear vulcameter (SIS V50). Two volume punches (for Mooney and volcametry) are available for the corresponding sample preparation. The SIS V50 can be used for classic volcametry in accordance with DIN53529 and for rheological measurements using different amplitudes, frequencies and temperatures. In addition, the measurement mode for very large oscillation amplitudes ("LAOS" = Large Amplitude Oscillatory Shear, Figure 7) including FT analysis for non-linear response signals is possible. The process analysis also allows the reaction kinetic evaluation of the vulcanisation parameter curves and process simulations ("vulcanisation simulation") can also be carried out using the SIS V50.

Figure 6: Sample preparation and raw compound testing of rubber compounds
Figure 6: Sample preparation and raw compound testing of rubber compounds
Figure 7: Non-linear response signal of a rubber compound under large shear deformation ("LAOS")
Figure 7: Non-linear response signal of a rubber compound under large shear deformation ("LAOS")

Vulcanisation using a heating press

Using a hydraulic, oil-tempered plate press (Collin plate press 200, see Fig. 8), it is possible to produce elastomer test plates for mechanical material testing and, if appropriate heating moulds are available, to vulcanise smaller elastomer products such as rubber balls. The heating press is also equipped with a water-temperature controlled cooling unit so that, for example, semi-crystalline thermoplastics (or thermoplastic elastomers) can also be moulded under defined cooling conditions. Finally, Figure 9 shows the vulcanisation moulds for the plate press.

Figure 8: Collin heating press for vulcanising elastomer sheets or rubber balls
Figure 8: Collin heating press for vulcanising elastomer sheets or rubber balls
Figure 9: Different vulcanisation moulds for the production of rubber test specimens; left and centre: plates for standard test specimens for mechanical material testing, right: mould for rubber balls
Figure 9: Different vulcanisation moulds for the production of rubber test specimens; left and centre: plates for standard test specimens for mechanical material testing, right: mould for rubber balls