Suggestions for halogen-free flame retardant nylon processing
0. Brief overview:
In the range of plastic melting temperature, most of the non-halogen flame retardants do not melt, but reach a certain high temperature and decompose directly. So when processing, the flame retardant exists in the form of solid micronized powder, which is equivalent to filler at this time. (1) When the processing temperature is too low, the plastic is not yet melted, the viscosity of the system is too large, and the shear heat is too high, causing damage to the flame retardant, and also causing uneven dispersion of the flame retardant. When the processing temperature is too high, the flame retardant can not withstand such a high temperature, and it will also directly decompose. (2) The combination of screw is too strong and the rotation speed of the host is too high, which will also cause the shear heat to be too high and cause the flame retardant to be damaged.
1、Formulation suggestion:
The following is the formula with 25% glass fiber content and 16% flame retardant addition which is easier to process.
PA66 2310g
PA6 500g
EPDM-MAH 100g
Silicone oil 10g
Glass fiber 1250g
Flame retardant LLHF-1001 800g
1098 Anti-oxidant 10g
Silicone masterbatch 20g
2、Powdering process.
PA66 (vacuum open package immediately), PA6 (vacuum open package immediately), EPDM-MAH, silicone oil, etc. 4 materials first with high-speed mixer high mixing 2 minutes. (If PA66, PA6 is not vacuum-packed, but a ton of packaging, certainly absorb water, it is recommended to use the high mixer for 10 minutes, you can dry the water) After the halogen-free flame retardants, antioxidants, silicone masterbatch into the high mix barrel, continue to high mix for 3 minutes.
3、Extrusion process
Screw combination: the use of weaker screw combination, shear block as far as possible to use 45 °, the shear block scattered. The total number of shear block 8 groups can be (plasticized section 4 groups, glass fiber shear section 4 groups).
Processing temperature: material conveying section 245℃, melt plasticizing section 265℃, shearing and dispersing section 250℃, compression section 260℃, die 265℃.
Host speed: medium speed
Vacuum extraction needs to be opened
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