Innovative debondable structural adhesive for ground testing of Gaia segments
In the frame of GAIA segments ground testing, a structural debondable adhesive was developed in collaboration between RESCOLL and ASTRIUM. This debonding on command is based on a process invented by RESCOLL and called INDAR INSIDE®. The non-space applications considered for this technology are dismantling of bonded parts for maintenance, upgrade and temporary assemblyor more generally further environmental friendly dismantling of parts.
Adhesives are nowadays widely used in numerous industries like automotive, aerospace, avionics or microelectronics, etc., for many reasons such as adherence in structural assemblies and in this particular case a new challenge appears: the easy dismantling of structural bonded joints. This innovative concept results from industrial constrains like maintenance or recycling needs.
Rescoll has developed and patented a process, called INDAR INSIDE®, which offers a simple and efficient solution to the disassembling of structural bonds. Based on the use of specific compounds activated by heating at a certain temperature, this new technology drastically reduces the dismantling time and fulfil the main characteristics required by this application, no change in processing (implementation, curing conditions, …) and no or slight modification of the requested mechanical properties of the adhesive.
The debondable adhesive was successfully used on the GAIA segments. The bonding-debonding process has been implemented several times with reliability and easy dismantling of the parts.
Innovations & Advantages
INDAR, which stands for INnovative Disassembling Adhesives Research, aims to solve the problem of the irreversibility of the bonding technology without damaging substrates. Indeed, it allows reusing old substrates, for maintenance and for sorting of the materials in function of their nature for recycling:
- Modification of industrial adhesives with specific compounds or development of custom debondable formulations
- Patented process for dismantling of an adhesive joint
- Dismantling on control by thermal activation
- Global mechanism
- Activation temperature tuned to the bonding specification
- INDAR helps assembly designers to think about bonding when reversibility is mandatory. Better dismantling efficiency is achieved when the debonding capability is integrated at the concept step.
This process is based on the incorporation, in a formulated adhesive or primer, of specific compounds. In a known range of temperature the additive starts to decompose, generating gases which induce interfacial stresses. After a certain time, theses stresses are sufficient enough to overcome adhesion forces and the adhesive comes off the substrate, adhesive failure occurs.
Several debonding temperatures are available, depending on the compounds and matrix formulations. Debonding temperature will be tuned to the requirements of the application (service life, substrates damage, etc.) Due to the kinetics of activation of the compounds, it is essential to keep a margin (at least 50°C) between maximal service temperature and debonding temperature in order to avoid premature activation.
Current and Potential Domains of Application
The non-space applications considered for this technology are
- Automotive: dismantling of tailgate (glazing and plastic body parts) or more generally further environmental friendly dismantling of parts
- Aeronautics: proof tests
- Others: building sealants, machining fixing