PLA resin can be processed in traditional PET extruder. A sheet thickness between 0.2-1.0 mm is recommended. General equipment requirements are: screw with L/D ratio between 24:1 to 32:1, and smooth stuff barrel is favorable. After drying, the stuff is stable in melt form.
PLA resin is different with other resins, and special purging sequences should be followed:
1. Cleaning extruder should be done with low-viscosity, general-purpose polystyrene or polypropylene, and the temperature of extruder should be brought to steady state.
2. Contamination of hopper system should be avoided, the humidity of the air should be kept below -40ºC air dew point.
3. The PLA resin can be introduced into extruder after step 1 and 2.
4. Adjust the temperature of equipment to the operating condition.
5. When shutting down, the machine should be cleaned with low-viscosity polystyrene or polypropylene.
Note:
1. It is critical that all drying and conveying/receiving systems should be free of all other contaminant and is vacuumed to ensure that there is no remaining other polymer dust before adding PLA. Since the presence of other polymer contaminant that cannot melt at PLA operating temperature will block screens.
2. When cleaning extruder with polypropylene, the thermally cross-linked one should be avoided.
PLA Resin
Rest method
Physical property
Density(g/cm3)
1.25±0.05
GB/T1033-1986
Melt index,g/10min(190ºC,2.16Kg)
2-10
GB/T3682-2000
Melting point(ºC)
140-155
GB/T19466.3-2004
Glass transition temperature(ºC)
56-60
GB/T19466.3-2004
Mechanical property
Tensile strength(Mpa)≥
50
GB/T1040-1992
Elongation at break(%)≥
3.0
GB/T1040-1992
Impact strength(KJ/m2,Izod)≥
1~3
GB/T1043-1992
Less ...
Results : decrease blood viscosity
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