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Twin Screw Extruder For Bioplastic Compounding

Recently there has been a huge growth in the development of bio-degradable plastics to reduce the environmental impact of the disposal of conventional oil-based plastics.
Plastics that are biodegradable and made of natural materials – provides businesses with eco-friendly alternatives for packaging and products, especially single-use items that contribute a lot of waste.
The bioplastic industry is still in its early stages but steadily growing and will begin replacing many disposable items made from petroleum-based plastic, such as cups, cutlery, packaging, containers and straws.

Material	Application
PLA	grocery bags, food wrap, bottles, cups, and plates,
PHA	Medical use including surgical sutures, drug delivery systems
PBAT	garbage bags, wrapping films, agricultural film
PBS	food packaging, agricultural mulch sheets, plant pots, hygiene products like diapers,
PCL	medical application sutures and fibers
PGA	high barrier packaging, surgical sutures

Types of biodegradable plastics

According to feedstock, biodegradable plastics are generally divided into two categories: biomass-based and fossil-based.

The property of biodegradation does not depend on the resource basis of a material but is rather linked to its chemical structure.

In other words, 100 percent biobased plastics may be non-biodegradable ,such as bio-based PE/PET. 100 percent fossil-based plastics can biodegradable,such as PBAT/PCL/PBS/PGA. Bioplastics like PLA/PHA/starch blends are both bio-massed and biodegradable.

Biodegradable plastics are applied in different industries depending on different mechanical properties such as stiffness,elongration-at-break,tensile strength ,thermostabilities, as well as other properties like vapor and barrierproperty.

Biobased ≠ biodegradable plastics

Biodegradable Plastic Compounding Extrusion Process

Preparation

The polymers, catalyst masterbatch and lubricant are pre-dried.PBAT/PLA with a weight ratio is pre- mixed with further components.
Dosing & Compounding

Melt-blended according to the list of formulations and processing parameters.
Cooling&pelletizing

According to the processing properties, such as viscosity, to choose the right pelletizing technology. When compounding PBAT,we usually choose underwater cutting

Typical Application

Thermoplastic starch (TPS)
Compounds of PLA/PBAT /PBS/CA/PCL/PHA
Compounds PLA/PBAT /PBS/CA/PCL/PHA with organic or mineral filler (talc/caco3)

Example:

Compounding PLA/PBAT on twin screw extruder

Twin screw extruder is perceived to be the most efficient technology for compounding modification.

For applications like mulch films, not only biodegradability but also mechanical properties are required.
PBAT is a highly flexible and designed for film extrusion. PLA is a biobased polyester with a high modulus of elasticity but low toughness. Blending the flexible PBAT with stiff PLA can potentially generate material with complementary properties without losing biodegradability.
Both PLA and PBAT are thermoplastics which can be processed using most conventional polymer processing methods.

Benefits of JIEYA Twin Screw Extruder For Bioplastic

Excellent Dispersion at High Throughput Rate
Optimum Do/Di means more free volume for dispersing and distributing as well as high material loading.

Easy Operation
Self-cleaning effect of the two intermeshing co-rotating screws result in fast cleaning and therefore fast change of formula.

Modular design
Modular designed screw element and barrel realize accurate control ,such as temperature, residence time ,degasing which are important for product quality.

Low Cost, Long Lifetime of Spare Parts
Equipped with CNC machining centers, our factory produces screws and barrels are manufactured by ourselves, enabling a tight control of quality and cost.