The surfaces of the parts to be bonded with adhesive tapes from CMC Germany must be clean, dry and free of grease or oil. In addition, the base to be bonded must be solid. Any loose layers of paint etc. must be removed beforehand.
According to the application and the base material, the effective bonding surface may be enlarged by roughening it. Depth of the roughening must be well under the depth of the adhesive layer to guarantee good anchorage of the adhesive in the roughened surface.
Grease, oil and other parting agents as well as contamination can all be removed with cleaning agents such as:
Surfaces with low surface energy
In the case of non-polar plastics such as
there are natural problems relating to bonding using standard adhesive tapes. Ask us for details of special adhesive tapes for these uses. These surfaces should also be chemically or physically pre-treated (e.g. using a corona pre-treatment).
Working temperature, final strength
The most favourable working temperature for using adhesive tapes is about 20°C. Bonding at less than 10°C should be avoided.
Bonding with soft PVC can be critical, since diffusion of the plasticiser may lead to a deterioration of the cohesion of the adhesive layer. Here, primer may effect a substantial improvement in the durability of the bond.
UV radiation, outdoor use
Not all plastics are suitable for continuous exposure to sunlight out-of-doors. Among the technical foils, polyester in particular can become brittle after only a few months? exposure to intense sunlight. We offer special types of adhesive tape for outdoor use. Please ask our advice in such cases, giving details of the probable exposure.
Impregnating varnishes, impregnating resins
Because of the enormous variety of impregnating agents available, it is impossible to make any generally-valid statement. In particular, impregnating agents containing styrene can be problematic. In many cases, internal testing is the only way to find out whether a adhesive tape wprks with the varnish or not. These test should be carried out at the customers company.
The ideal temperature lies between 15 and 25 °C. Relative humidity should be between 40 and 60%. Daylight, and especially direct sunlight, are to be avoided. The carton must be stored upright, to avoid any pressure-point damage.