Product Safety, Handling and Storage
Customers should review the latest Material Safety Data Sheet (MSDS) and label for product safety information, safe handling instructions, personal
protective equipment if necessary, and any special storage conditions required for safety. MSDS are available at www.momentive.com or, upon
request, from any Momentive Performance Materials (MPM) representative.
For product storage and handling procedures to maintain the
product quality within our stated specifications, please review Certificates of Analysis, which are available in the Order Center. Use of
other materials in conjunction with MPM products (for example, primers) may require additional precautions. Please review and follow the safety
information provided by the manufacturer of such other materials.
Processing Recommendations
Surface Preparation
RTV102, RTV103, RTV106, RTV108, RTV109, RTV112, RTV116 and RTV118 sealants will bond to many clean surfaces without the aid of primers.
These surfaces typically include many metals, glass, ceramic, silicone rubber and some rigid plastics. These adhesive sealant products will also produce
fair bonds to organic rubber and to some flexible plastics not containing fugitive plasticizers (which migrate to the surface, impairing adhesion). An
evaluation should be made to determine bond strength for each specific application. For difficult-to-bond substrates, use of a primer is suggested.
Primers SS4004, SS4044 and SS4179 are recommended for use with these sealants. Complete information and usage instructions for these primer
products are contained in a separate product data sheet.
Where adhesion is required, surfaces should be thoroughly cleaned with a suitable solvent such as naphtha or methyl ethyl ketone (MEK) to remove dirt,
oil and grease. The surface should be wiped dry before applying the adhesive sealant.
When solvents are used, proper safety precautions must be observed.
Application and Cure Time Cycle
Paste
-consistency products may be applied directly to clean or primed substrates. Where broad surfaces are to be mated, the sealant should be applied
in a thin, less than 6mm (1/4 in.) diameter, bead or ribbon around the edge of the surface to be bonded.
Flowable products may be applied to clean or primed substrates by pouring directly from the original container or dipping. These products will self-
level
on a surface, filling small crevices and surface voids. Depth of potted sections should not exceed 6mm (1/4 in.).
The cure process begins with the formation of a skin on the exposed surface of the sealant and progresses inward through the material. At 25°C (77°F)
and 50% relative humidity, RTV102, RTV103, RTV106, RTV108, RTV109, RTV112 and RTV116 sealants will form a surface skin which is tack-free to the
touch in 15 to 30 minutes. Once the tack-free skin has begun to form, further tooling of the adhesive sealant is not advisable.
Higher temperatures and humidity will accelerate the cure process low temperatures and low humidity will slow the cure rate.
As the adhesive sealant cures, acetic acid vapors are released from the sealant surface. The odor of acetic acid will completely disappear when curing
is completed.
A 3mm (1/8 in.) section of adhesive sealant will cure through in approximately 24 hours at 25°C (77°F) and 50% R.H. Since cure time increases with
thickness, use of these adhesive sealants should be limited to section thicknesses of 6mm (1/4 in.) or less.
Bond Strength Development
In addition to the effects of temperature and relative humidity, development of maximum bond strength will depend on joint configuration, degree of
confinement, sealant thickness and substrate porosity. Normally, sufficient bond strength will develop in 12 to 24 hours to permit handling of parts.
Minimum stress should be applied to the bonded joint until full adhesive strength is developed. Eventually the adhesive strength of the bond will exceed
the cohesive strength of the silicone rubber sealant itself. Always allow maximum cure time available for best results.
PACKAGING AND DISPENSING
RTV adhesive sealants from Momentive Performance Materials are supplied ready-to-use in collapsible aluminum squeeze tubes, caulking cartridges and
in bulk containers.
Collapsible aluminum tubes may be squeezed by hand or with the aid of mechanical wringers which allow more complete removal of material from the
tube. Air-operated dispensing guns may also be used with aluminum tubes and offer the advantages of improved control and faster application for
production line use. The sealant may be dispensed from caulking cartridges by using simple mechanical caulking guns or air-operated guns. Air-operated