Plastic recycling process to save CO2 and costs

Injection moulding process for processing recycled materials

The use of recycled materials improves the CO₂ balance. At the same time, contamination brings with it odour pollution and fluctuations in quality. With our innovative recycling processes for plastics, we are responding specifically to these challenges. ENGEL enables its customers to operate within a circular economy.

Advantages of the plastic recycling process

The regranulation of used plastics is an energy-intensive processing step in recycling. With our two-stage plastics recycling process, this step is skipped. Depending on the recyclate used, you save more than 400 Wh of energy per kilogram of plastic. This corresponds to a CO₂ reduction of 30%.

Picture shows component made from recyclate

With our injection moulding processes for the Circular Economy, you increase the recyclate content in the component. A recycling content of 50% is achieved with the skinmelt process. The percentage is much higher with the foilmelt process. In the two-stage process, no virgin material is used at all. The component thus consists of 100% recycled material.

Volatile components in the material such as gases or moisture are eliminated with our integrated degassing. Degassing enables a wider range of recyclates to be used, component quality without streaks and less tool build-up. Odour pollution is reduced enormously. Especially with lacquered components, you achieve beautiful surfaces thanks to degassing.

Picture shows possible contamination such as paper, metal or wood

Filter systems reliably remove contaminants from the recyclate. Depending on the design, they protect plasticising, hot runner and mould. Suitable filter systems are offered for different degrees of contamination. This prevents clogging of the mould, hot runner and sprue channels by foreign parts. In addition, the component quality increases.

Picture shows box made of plastic with recycled material

Design for recycling can be implemented with a visible high-quality outer skin and recycled material in the background. Our plastic recycling processes in the field of multi-component injection moulding are particularly suitable for this. Provided that the injection moulded part has the same polymer base. Produced components can be recycled again without any problems.

Advantages of the plastic recycling process

30% CO2 savings through direct processing of flakes

The regranulation of used plastics is an energy-intensive processing step in recycling. With our two-stage plastics recycling process, this step is skipped. Depending on the recyclate used, you save more than 400 Wh of energy per kilogram of plastic. This corresponds to a CO₂ reduction of 30%.

Solutions to increase the proportion of recycled material in the component by up to 100%

With our injection moulding processes for the Circular Economy, you increase the recyclate content in the component. A recycling content of 50% is achieved with the skinmelt process. The percentage is much higher with the foilmelt process. In the two-stage process, no virgin material is used at all. The component thus consists of 100% recycled material.

No odours, streaks or moisture residues in the component thanks to degassing

Volatile components in the material such as gases or moisture are eliminated with our integrated degassing. Degassing enables a wider range of recyclates to be used, component quality without streaks and less tool build-up. Odour pollution is reduced enormously. Especially with lacquered components, you achieve beautiful surfaces thanks to degassing.

More safety thanks to filtration of the melt

Filter systems reliably remove contaminants from the recyclate. Depending on the design, they protect plasticising, hot runner and mould. Suitable filter systems are offered for different degrees of contamination. This prevents clogging of the mould, hot runner and sprue channels by foreign parts. In addition, the component quality increases.

Realisation of Design for Recycling with ENGEL technologies

Design for recycling can be implemented with a visible high-quality outer skin and recycled material in the background. Our plastic recycling processes in the field of multi-component injection moulding are particularly suitable for this. Provided that the injection moulded part has the same polymer base. Produced components can be recycled again without any problems.

Picture shows Vice President Process & Application Technology at ENGEL Austria

Would you like to process used plastics reliably?

Take advantage of our expertise, plant engineering and technologies for processing plastic flakes or regranulate. We will be happy to advise you on the selection of the right plastics recycling process.

Contact us

Overview of our plastics recycling processes

Procedure	Product name	Industry	Applications	Process
Two-stage process		Automotive & Mobility, Technical Injection Moulding, Packaging, Electronics	Bumpers, engine covers, logistics, buckets, flower pots, drainage shaft	Direct processing of recyclates with degassing and filtration of the melt
Sandwich injection moulding	skinmelt, co-injection	Automotive & Mobility, Technical Injection Moulding, Packaging, Electronics	Furniture/furnishing, logistics (boxes), buckets	Multi-component injection moulding with high-quality material on the surface and recyclate in the core
Foil back-moulding	foilmelt	Automotive & Mobility, Technical Injection Moulding, Packaging, Electronics	Interior/exterior trims, trims for white goods, electronic products	Create functional, haptic and decorative surfaces with films - the film is back-injected with recycled material
PET / rPET processing		Packaging	Thin-wall packaging	PET processing with modified high-performance machines

Details on our plastic recycling processes

Two-stage process

The two-stage injection moulding process enables a circular economy with minimal use of resources. Contaminated regrind is processed directly at the injection moulding machine. The material is degassed and filtered in the process. This eliminates an entire work step: regranulation. This significantly reduces costs and energy consumption.

Your advantages with the two-stage process

Consistently high product quality despite recycled material

By integrating degassing, filtration and additivation into the injection moulding process, process-reliable processing is possible - even of contaminated recyclates.

Saving CO2, energy and costs

Direct processing of regrind in injection moulding requires more than 30% less energy for processing the recyclate, as regranulation is no longer necessary.

No odours, streaks or residual moisture in the component

Thanks to the integrated degassing, volatile accompanying substances are eliminated and a better component quality is achieved. Less fogging forms in the mould and the mould service life is increased.

Gentle fibre additives and cleaning of the recyclate

In addition to the filtration of the material, the process enables gentle fibre processing. With the help of the high fibre lengths achieved, you can produce components that meet high mechanical requirements.

Result

Wide range of applications for recycled materials
Component meets high quality requirements
Part of the manufacturing process (regranulation) is skipped - you save valuable energy

Plastics recycling processes in practice

Picture shows three ENGEL employees and the Austrian Federal Minister of Labour and Economy

ENGEL wins Austrian State Innovation Award for two-stage process

On 7 October 2024, Austrian Federal Minister for Labour and Economy, Martin Kocher, presented the award in Vienna. The State Award honours Austria’s most innovative companies, and the jury recognised ENGEL’s contribution as a groundbreaking transformation in the recycling process.

Increased efficiency through ENGEL's two-stage process

Post Consumer Recycled (PCR) plastic flakes are processed directly with ENGEL's two-stage process. The company AVK Plastics BV uses the technology to produce new pallets from shredded polyolefins. The customer saves costs and valuable energy through the plastic recycling process.

Direct processing of contaminated regrind

Thanks to the two-stage plastic recycling process, the material cycle can be closed with very little resource input.

Learn more

Flow behaviour of core material in detail | ENGEL

Sandwich injection moulding

co-injection, skinmelt

Sandwich components offer a circular economy solution. Recycled plastic waste such as post-consumer waste can be hidden inside the product. The recyclate is not visible on the surface.

Your advantages with sandwich injection moulding

Reduce CO2 footprint

By using recycled material, valuable resources such as raw materials can be saved.

Cost saving through recycled material in the core

With high quality material on the outer skin, you inject a lower cost material in the inner core of the component.

Weight reduction due to foamed core

Reduce the shot weight of the component with foamed core material. No sink marks are seen on the surface.

Increase mechanical properties

The fibre reinforcement in the core increases the strength of the component.

Result

Sandwich components have a visibly high-quality surface
Components with up to 50% recycled core can be achieved

Plastic recycling process with different types of sandwich injection moulding

Picture shows animation of the co-injection moulding process

The animation shows the sequential flow of the co-injection process:

Injecting skin material (green)
Injection core material (grey)
Sealing with skin material (green)

Image shows animation of the skinmelt injection moulding process

This animation shows the sequence of the dosing process:

The upper aggregate contains the skin component (green). The main aggregate contains the core component.
Before injection, the skin component is transferred to the main unit.
The filling process is identical to the conventional injection moulding process.
The skin component forms the edge layer. The core remains inside.

Plastic recycling process with different types of sandwich injection moulding

co-injection

The animation shows the sequential flow of the co-injection process:

Injecting skin material (green)
Injection core material (grey)
Sealing with skin material (green)

skinmelt

This animation shows the sequence of the dosing process:

The upper aggregate contains the skin component (green). The main aggregate contains the core component.
Before injection, the skin component is transferred to the main unit.
The filling process is identical to the conventional injection moulding process.
The skin component forms the edge layer. The core remains inside.

Bucket produced in co-injection plastic recycling process | ENGEL

Seat shell manufactured using the skinmelt injection moulding process | ENGEL

Pet food can manufactured using the co-injection process | ENGEL

Picture shows transport box with a core made of recyclate, manufactured by ENGEL

Types of Sandwich Injection Moulding - Functionalities & Applications

What are the types, functions and applications of sandwich injection moulding? Find out the answers in the blog post.

Sandwich injection moulding as an ideal application for recyclates in practice

- technical moulding
Transport box manufactured using the skinmelt plastic recycling process

Recycled material hidden in the core - virgin material in use as skin material.
- packaging
Bucket manufactured in the co-injection plastic recycling process

Bucket production on a duo speed with two injection units: PCR recyclate is injected in the core and virgin material in the outer skin.

Picture shows plastic components manufactured by ENGEL using the injection moulding process Foil Back Injection

Foil back-moulding

foilmelt

In film back injection moulding, the recycled material is bonded with a film. This happens directly in the mould during the injection moulding process. Only the film is visible on the surface. The product is significantly upgraded.

Your advantages with the foilmelt process

Facilitated Design for Recycling

With the outer film you achieve an improved component surface. The recycled material remains hidden in the background.

Flexible Designs

You can implement different designs. Switching to a new design is quick and uncomplicated.

Elaborate Effects

Design effects such as metallic, aluminium, chameleon effect or holograms on the surface of the component are possible.

One-Shot Process

Direct injection moulding production of the surface design in a fully automated production cell. Without rework.

Result

The recyclate is hidden behind the film layer
Your plastic component is provided with a film layer through surface finishing and functionalisation
The component is visually upgraded

Plastic Surface Finishing with Various Types of Film Back-moulding

Picture shows process for film insert moulding procedure

Preforming the film
Positioning of the insert by a robot
Hot substrate is injected by standard back- injection and fuses with the film
After cooling, the material and film are ejected in one piece

Picture shows process for in-mould decoration procedure

Foil is inserted into the tool
Foil is positioned in X and Y direction and clamped by a sealing frame
Hot substrate material is injected using the standard back-injection process and fuses with the PUR lacquer layer
After the material has cooled down, the film is ejected in one piece

Picture shows process for roll-to-roll in-mould labelling procedure

Foil is inserted into the tool
Infrared preheating and vacuum preforming pull the film into the mould
Hot carrier material is injected in a standard back-injection process and fuses with the foil
When closing the tool, the film is cut by cutting edges
After cooling, the material and film are ejected in one piece

Plastic Surface Finishing with Various Types of Film Back-moulding

Film-Insert-Moulding

Preforming the film
Positioning of the insert by a robot
Hot substrate is injected by standard back- injection and fuses with the film
After cooling, the material and film are ejected in one piece

In-mould decoration

Foil is inserted into the tool
Foil is positioned in X and Y direction and clamped by a sealing frame
Hot substrate material is injected using the standard back-injection process and fuses with the PUR lacquer layer
After the material has cooled down, the film is ejected in one piece

Roll-to-roll in-mould labelling

Foil is inserted into the tool
Infrared preheating and vacuum preforming pull the film into the mould
Hot carrier material is injected in a standard back-injection process and fuses with the foil
When closing the tool, the film is cut by cutting edges
After cooling, the material and film are ejected in one piece

Surface-finished plastic component in the fascia sector | ENGEL

Foil Back-moulding: Plastic Surface Finishing and Functionalisation of Plastic Components in Practice

- technical moulding
- automotive and mobility
- electronics
Flexible Process for Quick Design Change

Foil back-moulding on a duo 350 with a roll-to-roll IML application. The film is fed via a roll, thermoformed on the machine and remains on the component.
- automotive and mobility
Production of Aesthetic Vehicle Interior Components

Interior Door Panels for Vehicles with Different Surface Properties Thanks to Film Back-moulding.
- automotive and mobility
Automotive Front Panel with Decorative Foil and Polyurethane Coating

Production is done with one machine and in one cycle using film back-injection and flooding. For an efficient and simple process.

Picture shows thin-walled container produced from PET

PET / rPET processing

Produce thin-walled PET containers in just one process step. This is possible with the powerful injection unit of our e-speed injection moulding machine. This significantly expands the range of applications for PET and rPET.

Learn more

Your advantages with rPET in thin-wall injection moulding

Use the closed recycling loop

PET can be recycled an infinite number of times. PET products can contain up to 100% recycled content.

Direct processing of PET flakes

ENGEL is the first supplier to enable thin-wall injection moulding for PET. Realise high recycling rates directly on the injection moulding machine.

Compliance with the law

From 2025, all plastic packaging must have a recycled content of at least 30% and be 100% recyclable. With our plastic recycling process, you meet the required quotas. In addition, they must be 100% recyclable.