ISMR June 2022 - Page 20

FOCUS ON BONDING

A FIRM GRIP

We outline the benefits of metal bonding technologies for a wide range of disparate applications .

“ There is no such thing as one adhesive for metals . The properties of the adhesive ( such as composition , viscosity or temperature resistance ) must be matched to the surface to be bonded .”
Image : Shutterstock . com .

Metal is relatively well suited for bonding . Nevertheless , it is important to find the right product for the corresponding application . The choice of adhesive , a load analysis as well as potential surface treatment are decisive factors that lead to a good bond . Bonding can then be a strong alternative to welding , screwing or riveting . These are advantages that are used today in mechanical engineering , vehicle construction , architecture , construction , electrical industry etc .

“ A wide range of metal adhesives or adhesive tapes is available today for bonding metals to each other or to other composite materials : for high tensile shear strength , as well as for good temperature and chemical resistance or dynamic loads ,” explained bonding specialist , 3M .
“ Not only when bonding metals does the selection of adhesives or adhesive tapes strongly depend on the energy of the surface to be bonded . The surface energy is a measure of how well an adhesive can adhere to the surface to be bonded . Compared to many plastics , metals have a high surface energy of between 1,000 and 5,000mN / m and are therefore suitable for good wetting with adhesives ,” it added .
According to FEICA ( the Association of the European Adhesive and Sealant Industry ), the European market for adhesives and sealants is forecast to grow to € 22.2 billion by 2026 , at a compound annual growth rate ( CAGR ) of 3.6 % for 2021-26 .
Adhesives and sealants
Worker using glue gun with adhesive to fix metal steel on roof ( Shutterstock . com ).
An adhesive is a compound that adheres or bonds two or more substrates together . Adhesives may come from either natural or synthetic sources .
“ The strength of attachment , or adhesion , between an adhesive and its substrate depends on many factors , including the means by which this occurs . Adhesion may occur either by mechanical means , in which the adhesive works its way into small pores of the substrate , or by one of several other chemical mechanisms . In some cases , an actual chemical bond occurs between adhesive and substrate . In others , intermolecular forces ( like van der Waals ) hold the substances together . A third involves the moisture-aided diffusion of the glue into the substrate , followed by hardening . Good wetting of the surface is a pre-requisite for this kind of adhesion ,” explained FEICA .
20 | sheetmetalplus . com | ISMR June 2022