SEMICOSIL® 987 GR
SEMICOSIL® 987 GR is a non-slump, thermally curable, addition curing, one-part silicone elastomer which can be used as sealing adhesive
- One-part, ready-to-use, heat curing silicone
- High flexibility (low-stress-adhesive) for FIPG bonding
- Primerless adhesion to many substrates
- General purpose sealing adhesive
- Electronics industry
- FIPG - sealing of electronic control unit substrates (cover, housing)
- Supports mass production processes with end-of line QC-control
SEMICOSIL 987 GR can be applied as sealing adhesive for FIPG bonding of thermoplastics (Polybutylenterephthalates, Polyamides) and metals (Al, steel) for mass production processes.
On suitable substrates adhesion built up is accomplished via chemical linkages to polar anchor groups of the substrate. Examples for processing concepts are given in the following.
As type of substrates, concentration and accessability of functional anchor groups may vary, it is highly recommended that customers carry out adhesion tests for in-line quality check and adhesion performance after aging before fixing processing parameters. It is customers responsibility to check fitness for the specifc application and to ensure reproducability of surface quality.
SEMICOSIL® 987 GR shows good primerless adhesion to many substrates. We recommend running preliminary tests to optimize conditions for the particular application. Comprehensive processing instructions are given in our leaflet „ Room Temperature Vulcanizing (RTV) Silicones (Materials and Processing Guidelines)” which can be downloaded from WACKER Chemie AG website.
All equipment and surfaces must be clean and free of contaminants that will prevent adhesion and/or inhibit the cure of SEMICOSIL® 987 GR.
Separation layers on bonding substrated may be formed from residues of previous processes, from migrating additives or unintended contaminations. Examples of separating molecules among others can be processing fluids or deforming agents that are not able to built chemical links to reactive and accessible anchor groups of the substrate surface or to the silicone elastomer. Examples of inhibiting contaminants are sulfur containing materials, plasticizers, urethanes, amine containing materials and organometallic compounds – especially organotin compounds. If a substrate’s ability to inhibit cure or built up adhesion is unknown, a small scale test should be run to determine compatibility.
Safeguarding of reproducable and suitable surface quality is recommended. State of the art methods include in-line surface pretreatments like plasma processes or laser pretreatment.
Because of the pronounced shear thinning effect SEMICOSIL® 987 RB GR can be dispensed easily with all dispensing equipments.
Since silicones dissolve notable amounts of air, an in-line degassing is recommended.
SEMICOSIL® 987 GR works best when cured at 125 °C or more.
Curing time should be adapted to the size and heat sink properties of the components and parts. The term "curing" time describes the time needed for solidification of the material. For typical substrates adhesion built-up is accomplished within this time, which can be observed by cohesive failure upon adhesion test.
However, depending on the surface quality of the bonding surfaces, time to adhesion might differ from given curing profiles.
In the interest of robust processing it is highly recommended that for selected curing temperatures & times aging tests on specific customers parts are carried out to storage safeguard the process.
The 'Best use before end' date of each batch is shown on the product label.
SEMICOSIL® 987 GR should be stored between +5 and +25°C in the tightly closed original container.
Storage beyond the date specified on the label does not necessarily mean that the product is no longer usable. In this case however, the properties required for the intended use must be checked for quality assurance reasons.