Priming of surfaces to achieve improved adhesion has been employed in industry for many years and is of particular importance in the use of silicone adhesive sealants and 2-part RTV silicone rubbers. Silicone adhesives and some 2-part rubbers have built in adhesion promoters - with these products the use of a primer will only be required for use with substrates that are exceptionally difficult to bond to. Most 2-part silicone rubbers will not have any adhesive qualities and the use of a primer will be essential if adhesion is required.
Due to the large variety of substrates any recommendations regarding adhesion and the use of primers can only be taken as a guide, we always recommend thorough testing for adhesion of any system prior to production.
Silicone primers are normally supplied in the form of quick drying solvent solutions and are available in bottle or can packages.
A good primer must have certain properties and sometimes perform several functions:
It is essential that a uniform, thin coating of the selected primer is applied and allowed to dry completely before bringing it into contact with the silicone elastomer system.
All silicone primers are supplied as solutions in a wide variety of organic solvents. Some of these solvents present a greater hazard to the user than others. Full details of the solvents and any other potentially hazardous components are given in the individual product Safety Data Sheets, which are available on request.
NB: Always handle primers in well-ventilated areas away from any potential sources of ignition.
Before selecting a material careful consideration should be given to the relevant Technical Data Sheet and the Substrate Adhesion Guide in our Primer product information sheet. You can also use the Product Selector at the top of the page or, for further advise, or contact our technical team.