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Proper Surface Prep: An Adhesive’s Best Friend

Posted on 2/13/2015 12:04:21 PM By ASC
  

A strong adhesive bond requires the right adhesive for the substrates, but also correct preparation of surfaces being bonded. Bonds can experience adhesive or cohesive failure. Cohesive failure is when the bonding agent breaks down, and it is typically due to inappropriate adhesive selection. Adhesive failure is when the bonding adhesive comes loose from the substrate; the potential for this can be decreased by proper surface preparation. Degreasing is a common step in surface preparation and involves removal of both grease and any loose dirt or debris with a solvent such as acetone or isopropanol. Abrasion can similarly clean a surface. In addition, appropriate use of mechanical or chemical abrasives creates a roughened surface and more surface area for the bond to form. In some cases, particularly with plastics, mechanical or chemical abrasion is not enough and a physical treatment is needed. Common physical treatments include flame treatment, corona discharge and plasma treatment, all of which alter surface reactivity for a better bond. A detailed list of etching solutions and treatment conditions is available here.