Dow Corning PR-1204 RTV Prime Coat - 10.9 oz Can

PR-1204 Prime Coat is a diluted solution of silane coupling agents and other active ingredients. The surface reactive components typically must be applied in a very thin layer for best bonding. The solvents used in these products serve to deliver the active ingredients in a thin, uniform coating, enhance surface cleaning, and in some cases, aid in the penetration of the active ingredients into the bonding surface. Primers can be used to increase design flexibility, reduce total costs or increase performance reliability of electronic systems. They do this by enabling adhesion to lower-cost substrates or lower temperature processes which reduce energy budgets, among other possibilities.

PR-1204 Prime Coat is similar to DC1204, which is no longer in production. Dow Corning has tested it and found that it performed similarly to DC1204. However, your conditions and methods for use of this product are beyond their control. If you were instructed to use DC1204 in an aircraft service bulletin, maintenance manual or other document, you should verify that PR1204 is a suitable replacement.

These products should be applied in a very light, even coating by wiping, dipping or spraying. Excess material should be wiped off to avoid over-application, which generally appears as a white, chalky surface. When dip or spray coating, diluting by a factor of 2 to 4 with additional solvent may avoid excessive build-up. Apply additional cleaner/primer to the cloth every 3 to 5 minutes to ensure fresh material can react with the substrate.

Preparing Surfaces
The active ingredients must thoroughly wet out and coat the bonding surfaces. Mild abrasion, solvent cleaning, plasma, corona discharge and other pre-treatments have been used to clean and enhance surface reactivity to bonding. In general, light surface abrasion is recommended whenever possible, because it promotes good cleaning and increases the surface area for bonding. Surfaces should be cleaned and/or degreased with naphtha, mineral spirits, methyl ethyl ketone (MEK) or other suitable solvents that will remove oils and other contaminants that may be present. A final surface wipe with acetone or IPA may also be helpful. Different cleaning techniques may give better results than others. Users should determine the best technique for their application. For especially difficult to bond to surfaces, it may be necessary to increase the surface reactivity by chemical etchants or oxidizers, or by exposing the surface to UV, corona, plasma or flame sources. Allow solvents to completely evaporate before applying the primer.

Processing/Curing
These products require moisture in the air to cure, and are generally cured at room temperature and in a range of 20-90% humidity for 1 to 2 hours. Low humidity and/or low temperature conditions require longer cure times. Mild heat acceleration of the cure rate may be possible, but temperatures above 60°C (140°F) are not recommended. During application, the carrier solvent typically evaporates off quickly, allowing the active ingredients to begin to react with atmospheric moisture and bonding surfaces. For optimal bonding, different cure times may be required for different temperature and humidity conditions. Users should determine the best cure schedule and conditions for their applications. The desired silicone elastomer should be applied after the primer, prime coat or adhesion promoter has fully cured.

Usable Life & Storage
Shelf life is indicated by the "Use Before" date found on the product label. For best results, Dow Corning primers, prime coats and adhesion promoters should be stored below 32°C(90°F). Special precautions must be taken to prevent moisture from contacting these materials before use. Containers should be kept tightly closed and head or air space minimized. Partially filled containers should be purged with dry air or other gases such as nitrogen to maximize shelf life. Small amounts for immediate use should be poured into clean, dry containers and discarded when finished. Material should not be used once it takes on a milky appearance or a large amount of white precipitate is observed, indicating moisture contamination. Repeated opening of the container can cause a small amount of white precipitate to form inside the container cap area, which does not affect the bulk material.

This product is neither tested nor represented as suitable for medical or pharmaceutical uses.