Hein Colouring Procedure
for Expandable Polystyrene (EPS)
using the Hein® Special Screw Mixer
With this process, you will achieve excellent adhesion of the colourant by rolling it in the bead (in the mixer) even before it is finally bonded by the steam in the pre-expander.
- Filling of the revolving mixer with raw EPS material into hopper (9) *. The raw EPS raw material has to be dry at room temperature to avoid condensation. Don’t close the mixer.
- The appropriate quantity (see dosage) of the dry Hein®-Colourant has to be added slowly into the revolving mixer(25). The colourants are supplied as powder pigments and contain additives which facilitate the bonding of the colourant with the EPS raw material. After a period of 10 to 15 minutes, the colourant is well mixed with the raw EPS beads.
- The fixing agent Isopropanol (Isopropyl alcohol, CAS No. 67-63-0) has to be filled slowly from the top (25) * into the revolving mixer. The colouring process is finished when the fixing agent is completely vaporized and the EPS material is absolutely dry again. Through adding the fixing agent, the bonding of the additives of the colourant with the EPS is brought forward. At room temperature (18-25ºC), this step of the colouring process takes approx. another 15 to 30 minutes.
To avoid lumps, the mixer must not be switched off after adding the fixing agent. The mixer should run until the raw material is completely dry
- After a total of 30 to 45 minutes, you will get a completed, free flowing, lump free and dust free EPS raw material. When discharged (7) *, the coloured EPS material can pre-expanded or processed at once. If required, the coloured raw material can also be stored like white raw material.
Dosage per 1000 kg EPS raw material:
1 kg Hein8-Colourant powder
plus 4 litter fixing agent Isopropanol
You can obtain Hein® Special Screw Mixer from us as well. It is available as Type 1 (500 kg) and Type 2 (1000 kg).
* With reference to the detailed operation instructions for the Hein® Special Screw Mixer.
Note: The mixer has to be grounded electrically. In case large quantities of EPS have to be coloured, the drum of the mixer has to be well ventilated (explosion-proof suction blower, approx. 500 watt-motor). The same applies for room-ventilation.
Smoking is strictly forbidden in this area!
Above procedure is based on our experiences. Due to various unknown influences, the company using the colouring process has to undertake examinations and trails themselves. Above procedure is given without any obligations from our side. Existing laws and pre-cautions have to be obeyed by each user of our products under his own responsibility.