Plastic adhesives: Choosing adhesives for plastics

The exact identity of both joining partners, the condition of their surfaces and the demands on the bond are essential. Also describe the geometry, direction of loading, service environment and planned way of applying the adhesive. “Plastic” alone is not specific enough: plastics and their surfaces can differ considerably in how they are wetted. This information helps identify products worth assessing for your application and whether surface pretreatment may be needed.

PE and PP are plastics with low surface energy. This can make it harder for an adhesive to wet the surface and form a reliable bond. These materials may require an adhesive designed for them or suitable surface pretreatment. The right approach depends on the actual material, selected product and loads on the joint. Check the manufacturer's information and test the bond on the real component before deciding.

It is useful when the material, surface condition or selected adhesive system requires it. Contamination can impair adhesion, and some plastics need additional treatment to improve wetting. The type and extent of treatment depend on the joining material, adhesive and expected stresses. There is no single treatment that suits every plastic. Match cleaning, any additional pretreatment and processing to the guidance for the specific product.

Geometry affects how forces enter the bonded area. A broad area under shear distributes forces differently from peel or cleavage loading, which can concentrate them at an edge or in a small region. Bond area, component shape and direction of loading therefore matter when choosing a plastic adhesive. A sketch and details of the expected service loads will help us assess the potential joint and processing method for your enquiry.