Instructions for using technical adhesive tapes from CMC

Surface characteristics

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.

Characteristic of surfaces not properly cleaned can be the formation of pearling on wetting the surface with water. When the surface tension is high, the water droplets will spread to form a film, when one can assume the surface is in optimum condition for bonding. 

Mechanical cleaning 

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.

Chemical cleaning 

Grease, oil and other parting agents as well as contamination can all be removed with cleaning agents such as:

  • acetone
  • toluene
  • isopropanol
  • ethyl acetate.


First you must check carefully that the solvent you intend using will not damage the surface to be cleaned.  When using solvents, be sure to follow the manufacturer?s safety instructions implicitly. For many surfaces the gentle cleaner CMC 56032, which does not attack sensitive plastic surfaces, will be suitable. First of all however, you should test this on a concealed area. Simple application: spray on, allow to work briefly, then wipe off. Once surfaces are cleaned, they should be protected against getting dirty again (fluff, fingerprints etc.).

Cleaner for the removal of plastic residues: we recommend the use of e.g. CMC 56030 citrus cleaner for industry and the workshop on a natural basis / non corrosive, very effective and quick-acting. For cleaning adhesive residues, oil, grease, resin and tar, lubricants, graffiti, rubber marks or fresh PU-foam.

Surfaces with low surface energy

In the case of non-polar plastics such as

  • polypropylene PP
  • polytetrafluoroethylene PTFE (e.g. Teflon­)
  • polyethylene PE
  • rubber, silicone

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).

So-called primers are also very effective and relatively easy to work; these can make some difficult surfaces very much easier to bond.

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.

If there is too large a temperature differential between the two surfaces to be bonded, condensation may occur and prevent the establishment of a proper bond.
Depending on the material and the workpiece, the adhesive tape should be bonded using high pressure whenever possible. Hard polystyrene rollers may be helpful for this.

Pressure sensitive adhesives use viscous flow to archieve substrate contact area. Final adhesive strength is attained after about 72 hours in the case of most tapes. By judicious heating (say to about 50-65°C/1 hour), this time can be shortened.

PVC, plasticiser

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.

Storage

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.
The adhesive tapes should be preserved for as long as possible in their original packaging / foil bags. Remove them as shortly as possible before they are to be re-used.

Note: Our recommendations for application are given to the best of our knowledge, but are offered without guarantee as to accuracy. They do not release the end-user from the obligation of satisfying themselves as to the suitability for the intended purpose or procedure.

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