Biograde B-M
· Greater than 98% biodegradability when tested to ISO14855
· Can be used for injection moulding and profile extrusion
Description
BIOGRADE B-M is a fully biodegradable plastic based on a blend of thermoplastic starch (TPS), aliphatic polyesters (AP) and natural plasticizers. This grade of resin is compatibilised to offer a high level of mechanical strength, good elongation properties and toughness. The resin is based on corn starch which is a renewable material. The resin does not contain polyolefins.
Applications
· Biodegradable injection moulded products such as cutlery, toothbrushes, combs, shavers, golf-tees, plant markers, etc.
· Extruded tubes and rods
· Biodegradable stakes and pegs
· Biodegradable tags
· Extruded pipes
· Injection moulded caps and closures
· Compostable rigid products if wall thickness is kept below 1 mm.
Properties
|
Properties
|
Test Method
|
Typical Value/ Unit
|
|
Melt flow index
|
ASTM D-1238
|
1.75 g/10 min (150 ˚C/0.325 kg)
315 g/10 min (190 ˚C/2.16 kg)
|
|
Density
|
ASTM D-4883
|
1.22 g/cm3
|
|
Melting Temperature Range
|
ASTM D-3418
|
70-80 deg.C
|
|
Tensile strength at break
|
ASTM D-883
|
19.5 MPa
|
|
% Elongation at break
|
ASTM D-883
|
1.89 %
|
|
Izod Impact
|
ASTM D-256
|
Notched 23.5 J/m,
Un Notched 161.8 J/m
|
|
Surface resistivity
|
ASTM S-257
|
1 X 1012 Ω/m2
|
Processing Conditions
BIOGRADE B-M resin can be processed on standard injection moulding machines or profile extruders. Due to differences in machine design and instrumentation the optimum processing conditions should be determined in an initial trial. The following set-up has been successfully employed and is recommended as a starting point:
Suggested Maximum Moisture 0.2 %
Processing (Melt) Temp 170 to 180 °C
Feed Throat Temperature 50 to 60 °C
Feed Zone Temperature 140 to 150 °C
Compression Zone Temperature 160 to 170 °C
Metering Zone Temperature 170 to 180 °C
Nozzle Temperature 170 to 200 °C
Mold Temperature 10 to 25 °C
Screw Speed 100 rpm
Back Pressure 5-8 bar
Injection Speed 100-130 mm/s
Specific Instructions for Moulding of BIOGRADE B-M Resin:
Before moulding the resin, the injection moulders barrel needs to be purged and cleaned of residual polyethylene or other polymers and then the BIOGRADE B-M resin can be used as the last cleaning step, after which the temperature can be adjusted to the correct settings.
Other Comments
1. The mouldings need to condition for 1-2 days after processing to develop their full strength. During the conditioning the starch component reabsorbs its moisture content making it more ductile.
2. BIOGRADE B-M resins can be blended with natural fibres such as flax, hemp, sisal and coconut hair (coir) to add reinforcement and to assist with water-wicking into thick section mouldings.
3. Wet resin should be dried before processing to limit degradation induced by water (hydrolysis).
