Recommendations for processing of halogen-free flame retardant nylon
0. Brief overview:
Within the plastic melting temperature range, most halogen-free flame retardants will not melt, but will decompose directly when they reach a certain high temperature. Therefore, during processing, the flame retardant exists in the form of solid fine powder, which is equivalent to a filler. (1) When the processing temperature is too low and the plastic has not yet melted, the system viscosity is too high and the shear heat is too high, causing damage to the flame retardant and uneven dispersion of the flame retardant. When the processing temperature is too high, the flame retardant cannot withstand such high temperatures and will decompose directly. (2) The screw combination is too strong and the host speed is too high, which will also cause excessive shear heat and cause damage to the flame retardant.
1. Recipe suggestions:
The following is a relatively easy-to-process formula with a glass fiber content of 25% and a flame retardant addition of 16%.
PA66 2310g
PA6 500g
EPDM-MAH 100g
Silicone oil 10g
Glass fiber 1250g
Flame retardant LLHF-1001 800g
1098 antioxidant 10g
Silicone masterbatch 20g
2. Powdering process:
Four materials, including PA66 (used immediately after opening the vacuum package), PA6 (used immediately after opening the vacuum package), EPDM-MAH, and silicone oil, were first mixed with a high-speed mixer for 2 minutes. (If PA66 and PA6 are not vacuum packed, but packed in one ton, they must have absorbed water. It is recommended to use a high mixer for 10 minutes to dry out the water.) Then add the halogen-free flame retardant, antioxidant, silicone Pour the masterbatch into the high mixing bucket and continue high mixing for 3 minutes.
3. Extrusion process
Screw combination: Use a weaker screw combination, try to use 45° shear blocks, and spread the shear blocks. The total number of shearing blocks is 8 sets (4 sets of plasticizing sections and 4 sets of glass fiber shearing sections).
Processing temperature: 245°C in the material conveying section, 265°C in the melting and plasticizing section, 250°C in the shearing and dispersing section, 260°C in the compression section, and 265°C in the die head.
Host speed: medium speed
Vacuuming needs to be turned on
