ELASTOSIL® AUX G 3244

Primer for silicone rubber
 ELASTOSIL® AUX G 3244 solvent-based mixture of siloxanes and reactive silanes used as adhesion promoter for silicone
rubbers

Properties
• Provides excellent adhesion onto various substrates.
• Solvent based
• Various application methods (e.g. coating, dipping, brushing, spraying)
• Further dilution in organic solvents possible

Specific features
• Adhesion promoting primer
• General purpose
• Solvent-based

Technical data
General Characteristics

These figures are only intended as a guide and should not be used in preparing specifications.

Application details
ELASTOSIL® AUX G 3244 is a solution of a siloxanes and reactive silanes in organic solvents. It is used to pretreat metallic,
ceramic, glass or other polymeric substrate surfaces to enable excellent adhesion towards subsequently vulcanized
ELASTOSIL® R solid silicone elastomers (HCR/HTV, peroxide curing).
After the solvents have evaporated, a rigid film of silicone resin is formed on exposure to atmospheric humidity. The primer
film adheres firmly to a large variety of substrates and serves as adhesion promoter for subsequently applied silicone
rubbers.

Processing
It is recommended to clean all substrate surfaces with solvents (e.g. white spirits followed by ethanol or acetone) prior to
the application of ELASTOSIL® AUX G 3244 . The primer may be applied directly or in diluted form with a variety of
application methods (e.g. coating, dipping, brushing or spraying). It is recommended to stir the primer thoroughly before
application.
The resulting primer layer should be as thin as possible. Usually the best results can be achieved with a primer layer
between 1 an 10 µm thickness, corresponding to a coating weight of 5 to 50 g/m². If the primer needs to be diluted,
organic solvents like white spirits or ISOPAR® E can be used in a ratio of up to 1:10.
After application of the primer, the solvent should be evaporated at room temperature and moderate atmospheric humidity
for at least 2 hours to allow for the formation of a consistent primer film. It is recommended to apply the silicone rubber
soon afterwards, but not later than 2 days. In some cases the adhesion can be improved by heating the primered substrate
after evaporation of the solvents to 100-150°C for up to one hour.
It is important to note that in some cases the initial adhesion will be sufficient for handling while the maximum adhesive
strength will be achieved after a few days.
When adhesion of silicone elastomers onto very smooth substrates has to be achieved it is recommended to roughen the
surface by grinding or blast cleaning. In case of metals the substrate should be given several hours time to regenerate its
oxygen layer before applying ELASTOSIL® AUX G 3244 .
Since adhesion is determined by the nature of the substrate, the applied silicone elastomer and the processing parameters,
proper trials are absolutely necessary
For detailed information please refer to the latest edition of our brochure “SOLID AND LIQUID SILICONE RUBBER
MATERIAL AND PROCESSING GUIDELINES”.

Packaging and storage
Packaging
This product is available in 0.8 kg bottles, 20 kg pails and 150 kg drums.
Storage
Important Note:
ELASTOSIL® AUX G 3244 is sensitive towards humidity. In contact with moisture the liquid primer becomes turbid and the
adhesive strength of the primer is impaired. ELASTOSIL® AUX G 3244 should therefore be stored in a sealed container
after usage. In addition, it is strongly recommended to stir or shake the primer thoroughly before applying.
The ‘Best use before end’ date of each batch is shown on the product label. 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.

Safety notes
Comprehensive instructions are given in the corresponding Material Safety Data Sheets. They are available on request from
WACKER subsidiaries or may be printed via WACKER web site http://www.wacker.com.