New trends in the recycling of composite materials and plastics

In an environment where material and energy resources are scarce, Cetim Grand Est has developed two ecological processes for recycling composite materials and plastic waste, which helps reduce the impact of materials on the environment and supports the company’s technological and ecological changes. .

For the past 10 years, Cetim Grand Est has been committed to researching the recycling of composite materials and plastic waste through its engineering and materials science and industrial future departments.

Cetim Grand Est is located in Mulhouse and Strasbourg in the northeastern part of France. The University of Strasbourg and Kanomika Research Institute nearby provide an environment conducive to technological innovation. Through various technological innovations, Cetim Grand Est supports its customers in their future-oriented projects.

Focus on the recycling of composite materials and plastics

At present, the global output of composite materials and plastics has reached 10 million tons and 350 million tons per year, respectively.

These materials, which were developed on a large scale in the last century, are now unavoidable. It is necessary to work hard to find technically and economically feasible recycling routes for them.

In fact, the scarcity forecast of non-renewable materials and energy resources is triggering stricter regulations and forcing the composite and plastic industries to gradually reduce their carbon footprint.

However, although the goals are the same, in fact, the historical backgrounds of the composites industry and the plastics industry are completely different.

The degree of automation in the composite material industry is generally not high. It is mainly aimed at niche markets. It produces high value-added durable products. In about 90% of the cases, it uses long fiber or continuous fiber reinforced materials and thermosets. Resin (such as unsaturated polyester).

Although the increase in the total annual production volume did not lead to an excessive increase in production waste, the service life of the first generation products (such as hulls, wind turbine blades and cover plates, etc.) designed 20, 30, or 40 years ago At the end of the year, the scrapped waste is increasing sharply.

Due to the insolubility of resin, in almost 90% of cases, the only way out for these accumulated wastes is landfill.

In this regard, although many studies have been carried out, this percentage has not declined over the years.

Obviously, there are technical solutions, but none of them can overcome economic feasibility barriers in a convincing way (except for carbon fiber-containing composite materials, but they only represent 4% to 5% of the market).

This situation is no longer acceptable today. For the composites industry, it is necessary to find a way to replace the traditionally used thermosetting resins.

On the one hand, the current material field is transforming through innovation. On the other hand, materials and processes are shifting closer to plastic processing.

In both cases, thermoplastic resins are used. Compared with thermosetting resins, thermoplastic resins have higher recycling potential. Once their recyclability is verified on an industrial scale, these materials will be used on a large scale.

In contrast, the plastics industry has a higher degree of automation, mainly for the mass market, using thermoplastic resins to produce low-value-added, short-life products. This short service life causes a large amount of waste to be generated every year.

Although channels for recycling materials do exist, only a small part of the waste stream (approximately 10%) is currently captured, and the other part of the waste stream captured is used for energy recovery (approximately 20%).

Therefore, on a global scale, nearly 70% of waste is scattered in nature or landfilled.

As with the composite material situation described above, this situation is now unacceptable. The plastics industry must increase the added value of the application (especially close to the application of the composite material industry) to increase the resin recovery rate.

Obviously, for these two industries with a clear division of labor, mutual understanding provides new prospects for waste recycling.

In this regard, Cetim Grand Est has developed two ecological technologies to meet the expectations of increasing the recycling rate of these materials.

Realize two technologies on the same production line

Using a step-by-step thermomechanical processing method, this innovative process allows continuous production from the recycling of semi-finished waste (in the form of large thermoplastic composite panels).

This production line to be industrialized is installed in the factory in Mulhouse. It adopts a flexible, cost-effective and multi-functional design method. Through an upgraded recycling method, it can recycle various thermoplastic plastic wastes. It has become a series of high value-added, cost-effective and competitive recyclable semi-finished composite materials.

Using the same production line, using two different feeding systems, the Thermosaïc and ThermoPRIME eco-technologies were developed to make full use of the recycling potential of composite materials and plastics.

Recycling thermoplastic composite waste: Thermosaïc technology

Starting from a pile of production waste (and then scrapped waste), Thermosaïc technology is to crush these materials to maximize the economic potential of their recycling.

This technology can retain the inherent value of the original composite material, and continuously shape the fragments into plates through hot pressing.

Compared with recycled short-fiber-reinforced compounds, Thermosaïc sheets have significantly better mechanical properties and high forming potential.

Recycling plastic or fiber waste: ThermoPRIME technology

Composite materials recycled using ThermoPRIME process

ThermoPRIME technology is based on the specific requirements of the application, formulating low value-added recycled plastics (controllable quality) to combine this polymer with continuous fibers or long fiber reinforced materials to produce high durability and Continuous laminate with economic recovery potential.

Industrialized application

At present, the recycling of thermoplastic composite material waste has become the subject of various studies, with the goal of finding a method for recycling such as glass fiber reinforced PPS with high added value.

Generally speaking, the aviation industry is interested in any technology that can recycle various production wastes (up to 40% of waste).

Using the same logic of economic optimization and reducing the environmental footprint of materials, a model laptop case currently being developed for the Kano Institute’s Fashion and Luxury Department is made of recycled materials and/or biomaterials. It uses an environmentally friendly design.

Through the LCFC (Low Carbon Footprint Composite Materials) cooperative project, Cetim Grand Est and the IS2M (Mulhouse Institute for Science and Surface Research) of the Kanomika Institute have joined forces to produce a combined recycled matrix material (polypropylene). Based on the material of bio-fiber reinforcement (nettle), a concept demonstration piece was developed.

Samples of products thermo-formed using ThermoPRIME®/Thermosaïc® technology

These samples show the interest of manufacturers and scholars in major subjects that meet the strong expectations of society.

This flexible and agile technology makes it possible to recycle all types of thermoplastics (from PP to PEEK) and reinforcing materials (glass fiber, carbon fiber, flax fiber, etc.).

It is mature enough to meet industrial needs through feasibility studies, and support industrial needs through feasibility studies, proof of concept, special formulations, and trial production.

Article source: PT Hyundai Plastics