Processing recycled PET (rPET) — especially 100% bottle flakes — demands a specialized PET extrusion machine. Moisture sensitivity, varying intrinsic viscosity (IV), and material impurities make the choice of extrusion technology the decisive factor in producing high-clarity, high-strength sheet.
TZ Machinery offers two industry-standard configurations for efficient, cost-effective rPET sheet production: the parallel twin screw PET sheet extrusion machine и ABA three-layer co-extrusion line. Each solves a different set of manufacturing priorities. This guide compares both so you can match the right line to your recycled PET processing goals.
Why Recycled PET Is Harder to Extrude Than Virgin Resin
Recycled bottle flakes behave differently from virgin PET pellets in three critical ways:
- Moisture sensitivity. PET hydrolyzes when heated with residual moisture. IV drops, and the resulting sheet turns brittle or hazy.
- Inconsistent melt flow. Flakes from different bottle grades vary in density and intrinsic viscosity, making uniform melting difficult.
- Contaminants. Labels, adhesives, and degradation byproducts must be removed or neutralized during extrusion.
These challenges explain why traditional single-screw systems need energy-intensive crystallization and pre-drying before extrusion. The two TZ Machinery configurations below were engineered to bypass or mitigate these steps.
Parallel Twin Screw PET Sheet Extrusion Machine: Best for High-Ratio rPET Flakes
[Image: Parallel Twin Screw PET Sheet Extrusion Machine – TZ Machinery]
When your feed contains high percentages of recycled bottle flakes — up to 100% rPET — the Parallel Twin Screw PET Sheet Extrusion Machine from TZ Machinery is the preferred engineering choice.
Direct Processing Without Pre-Drying
Traditional single-screw systems require lengthy crystallization and pre-drying processes to prevent IV drop caused by moisture hydrolysis. The parallel twin-screw design features multi-vent vacuum degassing systems that extract moisture and volatile impurities directly during extrusion. Bottle flakes can enter the process essentially as received.
Superior Mixing & Homogenization
The co-rotating twin screws provide intense shearing and dispersive mixing. This ensures uniform melting even when processing raw recycled flakes with varying densities or melt flows. The result is consistent sheet thickness and stable process parameters across batches.
Energy Savings
By eliminating energy-intensive pre-drying hoppers, manufacturers significantly reduce operational costs per ton of extruded PET sheet. Lower energy consumption also improves the environmental profile of the final product — a growing requirement in export packaging markets.
ABA Three-Layer Co-Extrusion Line: Best for Cost Optimization & Food-Contact Compliance
[Image: ABA Three-Layer PET Sheet Structure Diagram]
For manufacturers who want to maximize profit margins or meet strict food-contact packaging standards, the ABA PET Three-Layer Sheet Co-Extrusion Line offers an optimized structural design.
How the ABA Structure Works for rPET
The ABA structure sandwiches recycled material between two clean outer layers:
| Layer | Ratio | Материал |
|---|---|---|
| A — Outer layers | 20%–30% | Virgin PET resin or premium recycled material |
| B — Core layer | 70%–80% | 100% recycled PET flakes or internal edge-trim regrind |
The outer skin layers create a smooth surface finish and excellent transparency. They also meet food-contact requirements by trapping the core layer inside the structure.
Key Advantages of ABA Co-Extrusion
- Cost reduction. Reduces virgin material consumption while maintaining high structural performance. Recycled core material costs significantly less per ton.
- Enhanced visual appeal. Covers minor discoloration or imperfections typical of recycled flakes under a clear outer layer.
- Versatility. Layer ratios are easy to adjust depending on target sheet specs and market demands.
Comparison: Twin Screw vs. ABA Co-Extrusion Line
| Характеристика | Parallel Twin Screw Extruder | ABA Three-Layer Co-Extrusion Line |
|---|---|---|
| Primary material focus | Up to 100% recycled PET flakes | Virgin outer layers + recycled core |
| Pre-drying requirement | No pre-drying (vacuum degassing) | Depends on extruder configuration |
| Core advantage | Energy efficiency, direct flake processing | Lower material costs, clean surface finish |
| Best application | General thermoforming packaging, industrial trays | Food packaging, clear clamshell containers |
If your feedstock is predominantly virgin PET resin rather than recycled flakes, a single screw PET sheet extrusion production line may be a more economical fit.
Summary: Which TZ Machinery Line Should You Choose?
Choose the Parallel Twin Screw PET Sheet Extrusion Machine if your primary goal is processing high volumes of raw rPET bottle flakes directly — without the complexity and energy consumption of pre-drying. It is the strongest fit for high-ratio recycled content and industrial-grade sheet.
Choose the ABA PET Three-Layer Sheet Co-Extrusion Line if you need to optimize material costs by sandwiching budget-friendly recycled material between clean outer layers. It is the right choice for food-contact thermoforming packaging where surface quality and compliance matter most.
Both solutions engineered by TZ Machinery deliver robust operation, low energy consumption, and high melt quality tailored to modern sustainable plastic processing requirements.
ЧАСТО ЗАДАВАЕМЫЕ ВОПРОСЫ
Can recycled PET bottle flakes be processed without pre-drying?
Yes. Parallel twin screw extruders use multi-vent vacuum degassing to remove moisture and volatiles during extrusion. This eliminates the crystallization and pre-drying steps required by traditional single-screw systems.
What percentage of rPET can a twin screw extruder handle?
A parallel twin screw PET sheet extrusion machine can process up to 100% recycled bottle flakes. The co-rotating screw design maintains uniform melting despite variations in flake density and melt flow.
How does the ABA three-layer structure reduce material costs?
The core layer uses 70%–80% recycled PET flakes or edge-trim regrind, which costs less than virgin resin. Only the thin outer layers (20%–30%) use virgin or premium material, lowering total raw material cost per ton.
Is ABA co-extruded sheet safe for food contact packaging?
Yes. The clean outer layers trap the recycled core, preventing direct food contact with recycled material. This structure helps meet food-contact packaging requirements for clamshell containers and similar applications.
What is the typical layer ratio in ABA PET sheet?
Standard ratios are 20%–30% for each outer layer and 70%–80% for the core layer. Ratios can be adjusted based on target sheet specifications and market requirements.
Which machine is better for clear thermoforming packaging: twin screw or ABA?
ABA co-extrusion is generally better for clear food packaging because the virgin outer layers ensure high transparency and smooth surface finish. A twin screw line is better when processing very high rPET ratios for industrial or general packaging.
Does processing rPET affect sheet clarity and strength?
It can, if moisture and contaminants are not managed. Vacuum degassing and dispersive mixing in twin screw systems preserve IV, protecting both clarity and mechanical strength.
Can I switch between virgin PET and rPET on the same line?
Yes. TZ Machinery lines support feed ratio adjustments. ABA lines allow flexible layer ratio changes, while twin screw systems handle everything from virgin resin to 100% rPET flakes.
Get a Tailored Recommendation for Your rPET Line
Tell us your target sheet specifications, output width, and rPET feed ratio. TZ Machinery will recommend the configuration that fits your line — twin screw, ABA co-extrusion, or a hybrid setup.