Adhesion promotion. Dow DOWSIL PR-1200 is an adhesion promoter primer, a solution of silane coupling agents used to increase the bonding of room-temperature and heat-curing silicones to a variety of surfaces such as glass, plastics, metals, ceramics, and masonry. It also promotes adhesion of certain one-part silicone sealants and coatings to construction materials such as plywood, masonry, and metal.
Formulation. PR-1200 is a one-part, naphtha-based general-purpose primer for use with silicone elastomers and RTVs. Dow describes its primers, prime coats, and adhesion promoters as dilute solutions of silane coupling agents and other active ingredients whose surface-reactive components typically must be applied in a very thin layer for best bonding.
Application method. The primer should be applied in a very light, even coat by wiping, dipping, or spraying, with any excess wiped off to avoid overapplication, which can result in a white, chalky surface. When dip or spray coating, diluting by a factor of 2 to 4 with additional solvent can help prevent excessive buildup. Surfaces should first be cleaned and degreased, and solvents allowed to evaporate before priming.
Handling and storage. Because these materials are moisture-sensitive, containers should be kept tightly closed with headspace minimized, and stored below 32°C. Material should not be used once it takes on a milky appearance or shows a large amount of white precipitate, which indicates moisture contamination. Review the product and Safety Data Sheets before use.
Recommended For
Promoting adhesion of RTV and heat-cure silicones
Bonding silicones to glass, plastics, metals, and ceramics
Bonding to masonry and construction materials
Surface preparation before sealing or coating
Improving reliability of bonded PCB and assembly joints
Available Variants
PR-1200 PRIMER RED 309G — Red, 309 g can
PR-1200 PRIMER CLR 309G — Clear, 309 g can
Both variants are the same PR-1200 adhesion-promoter chemistry in a 309 g can, differing in color: the red version is tinted to make coverage visible during application, while the clear version leaves no visible tint on the finished surface.
Product Details
Product type: One-part silane-based adhesion promoter / primer
Color: Red and clear variants
Carrier: Naphtha-based solvent solution
Application: Very thin, even coat by wiping, dipping, or spraying
Storage: Below 32°C; keep tightly closed; protect from moisture
Container size: 309 g cans
Primary Industries
Electronics and PCB manufacturing
Construction and building products
Industrial bonding and sealing
Glass, metal, and ceramic fabrication
Standards and Certifications
None specified by source
FAQs
What does DOWSIL PR-1200 do?
PR-1200 is an adhesion-promoting primer that improves the bond between room-temperature and heat-curing silicones and surfaces such as glass, plastics, metals, ceramics, and masonry. Based on silane coupling agents, it prepares difficult surfaces so silicone sealants and coatings adhere more reliably in demanding assembly and construction applications.
How should PR-1200 be applied?
Apply it in a very light, even coat by wiping, dipping, or spraying, and wipe off excess to avoid overapplication, which can leave a white, chalky surface. For dip or spray coating, diluting two to four times with solvent helps avoid build-up. Clean and degrease the surface first, then let the solvents evaporate.
Why is the primer available in red and clear?
The two versions share the same adhesion-promoting chemistry and differ in color. The red tint makes it easy to see where primer has been applied and confirm complete coverage, while the clear version is chosen when no visible tint on the finished surface is acceptable or preferred.
How should PR-1200 be stored?
Because it is moisture-sensitive, keep containers tightly closed with minimal headspace and store below 32°C. Do not use material that has turned milky or shows a large amount of white precipitate, as that indicates moisture contamination. Pour small amounts for immediate use into clean, dry containers and discard leftovers.
Do I still need to clean the surface if I use a primer?
Yes. Priming complements cleaning rather than replacing it. Surfaces should be cleaned and degreased with a suitable solvent, allowing the solvent to fully evaporate before the primer is applied. Good cleaning increases surface area for bonding, and for hard-to-bond surfaces, additional surface activation may further improve adhesion.
