Steel / polymer / steel sandwich structures

Sandwich structures are made up of different layers, usually with :

• two often rigid faces, also known as "facings" (or skins);

• a central core in the middle and, sometimes, a bonding layer when the panel is glued.

The adhesive is deposited on the substrate, or on both sides of the organic core.

Composite sandwich structures are used in many industrial sectors (construction, transport, automotive, etc.). They are particularly well suited to bending stress modes.

In addition to their excellent intrinsic rigidity, these sandwich structures can be used for many other functions, including :

• Lightening ;

• thermal, electrical and acoustic insulation;

• amortization ;

• impact resistance ;

• fire safety (non-polymer core) ;

• aesthetics...

In addition to improving the mechanical, thermal and acoustic properties of sandwich panels, their suitability for large-scale industrial production is essential to meet cost constraints. Depending on the intended application, shaping and assembly requirements may also have to be met.

For many years, the core of sandwich materials has been the subject of constant evolution and innovation, both structurally and morphologically. As a result, sandwich construction today offers a huge variety of core structures:

• solid cores (solid or cellular materials) (foamed) ;

• woven and non-woven films ;

• honeycomb cores with circular, hexagonal or square cross-sections, corrugated or embossed cores, grid cores...

The various products offered here are sandwiches with lacquered or unlacquered steel facings and an organic core (thermoplastic and thermoset). Other materials such as wood, cellulose, fabrics, aluminum, copper, alloys, stainless steel, metal foams, mineral wools and perlites are not included.

This document presents steel/polymer/steel sandwich structures to provide, in particular, thermal insulation, weight reduction, shock resistance and damping. The process for implementing sandwich structures, substrate/frame adhesion, and key parameters on final adhesion and durability properties are also discussed.