Technology: physical holding or chemical holding (“bonding”)
Hard-soft combinations have developed considerably in recent years.
Whether in the automotive, industrial, sanitary – domestic applications or medical-pharmaceutical sectors, ‘composite’ systems have taken on a new role that conventional systems did not occupy…, either to integrate several functions in the same component (e.g. box with seal), or to solve the problem of assembly (e.g. membrane, micro part) where this is made ‘in mold’, or to improve performance (e.g. anti-slip seal during assembly).
In order for the sub-assembly to remain intact, the 2 components : HVR (Hot Vulcanisable Elastomer) and the substrate (TP, metal, glass, …) must be physically or chemically bonded.
The choice depends on a number of criteria:
- Application: if a perfect watertight is required, a bonded system is preferable
- Economic: the bonded solution is more expensive
- Geometric
Physical retention
The elastomer is physically retained on the substrate:
- Suitable for all types of substrates/elastomers
- The geometry of the substrate must be adapted
- The deformation capabilities of the overmolding are often limited
- The quality of the resistance of the elastomer on the substrate is limited
but the ‘mechanism’ can very often be sufficient.
HNBR or Pu overmolded core
FKM overmolded valve
Chemical bonding = Adherisation
The elastomer is bonded to the substrate using an adhesive or adhesives called ‘bonding agents’.
Several operations need to be carried out:
- Treatment of the substrate surface (sandblasting (if necessary) + degreasing (always))
- Application of the bonding primer (possibly with sparing) + drying/ baking + possibly a secondary bonding agent.
High adhesion performance and a wide range of combinations, suitable for all types of substrates and HCRs.
Some projects by Chevalier, Cleret, Eltec
Overmolded valve with bonding
Overmolded cable clamp with mechanical anchorage
Overmolded cover with self-adhesive LSR
Overmolded flap with mechanical attachment
Overmolded sleeve with bonding
Roller with bonding
Overmolded LSR silicone gasket
on stainless steel insert
Learn more about overmolding rubber onto metal or other substrates
To learn more about overmolding rubber, download our documentation. Don’t hesitate to contact us using the form if you have any questions or a project to develop.