Variations of the filler structure can have a drastic effect on the flow behaviour and so the processability of polymer compounds.
In the described case a masterbatch producer had changed the supplier of the carbon black. The new carbon black caused major problems in production.
The report describes a fast and reliable test method to characterise the influence of filler properties on the flow behaviour of a polymer masterbatch.
Materials and methods:
- Basic polymer: SAN
- Filler: 30% carbon black
- (Type 1 and type 2)
- Torque Rheometre RheoDrive4
- Mixer sensor Rheomix600OS
- Roller rotors
- Mixer temperature: 230°C
- Rotor speed: 40 rpm HAAKE PolyLab
- Sample weight: 40g SAN, 18 g carbons black
In the beginning only the base Polymer (SAN) was introduced into the running mixer. After 3 minutes the mixer was opened again and the Carbon black sample was added into the mixing process.
During the whole mixing time the torque and the melt temperature were recorded.
Results and discussion:
The diagram below shows the result of the two mixer tests in one graph.
The test shows that identical amounts of different types of carbon black can result in a pronounced change in the flow characteristics.
The described test shows, that the mixer test is an easy and fast method to describe the effect of fillers on the flow behaviour of polymer compounds. Thus the mixer test can help to prevent problems in production.