Adhesion promotion for plastics. Dow DOWSIL PR-1205 Prime Coat is a one-component, dilute solution of silane coupling agents used to increase the bonding of room-temperature and heat-curing silicones to a variety of surfaces such as plastics, metals, and ceramics. Dow notes it is specially formulated to increase adhesion of a wide range of silicones to plastics, including more difficult types such as acrylic and polycarbonate.
How primers work. As with Dow's other prime coats, PR-1205's surface-reactive silane components must be applied in a very thin layer to achieve optimal bonding. The solvent carrier delivers the active ingredients in a thin, uniform coating and aids surface cleaning, helping the silicone form a strong bond to the treated substrate.
Important limitation. Dow notes PR-1205 is not recommended for use with addition-cure silicones such as SYLGARD 170, 184, and 186 Silicone Elastomer Kits. It is intended for use with the RTV and heat-cure silicones it is formulated to promote, particularly on plastics, ceramics, and composites.
Application and storage. Apply in a very light, even coat by wiping, dipping, or spraying, wiping off excess to avoid a white, chalky over-application. Because it is moisture-sensitive, store below 32°C, keep tightly closed, and do not use if it becomes milky. Review the product and Safety Data Sheets before use.
Recommended For
Promoting silicone adhesion to plastics
Bonding to difficult plastics (acrylic, polycarbonate)
Bonding to metals and ceramics
Surface preparation before sealing or coating
Improving reliability of bonded assemblies
Product Details
Product type: One-part silane-based adhesion promoter / primer
Color: Clear (light straw per some distributor data)
Formulated for: Plastics including acrylic and polycarbonate; also metals and ceramics
Not recommended for: Addition-cure silicones (e.g. SYLGARD 170/184/186)
Storage: Below 32°C; keep tightly closed; protect from moisture
Container size: 348 g can
Primary Industries
Electronics and PCB manufacturing
Plastics fabrication and assembly
Industrial bonding and sealing
Consumer product manufacturing
Standards and Certifications
None specified by source
FAQs
What does DOWSIL PR-1205 do?
PR-1205 is a silane-based adhesion-promoter primer that improves the bond between room-temperature and heat-curing silicones and surfaces such as plastics, metals, and ceramics. It is specially formulated to promote adhesion to plastics, including difficult ones like acrylic and polycarbonate, where silicones often struggle to bond.
How is PR-1205 different from PR-1200 or PR-1204?
While PR-1200 and PR-1204 are general RTV primer coats that are strong on metals, glass, and masonry, PR-1205 is specifically formulated to enhance silicone adhesion to plastics, including tough substrates like acrylic and polycarbonate. Choose PR-1205 when bonding silicones to challenging plastic surfaces.
Can PR-1205 be used with any silicone?
No. Dow notes that PR-1205 is not recommended for use with addition-cure silicones, such as the SYLGARD 170, 184, and 186 elastomer kits. It is intended for the RTV and heat-cure silicones it is formulated to promote. Confirm compatibility with your specific silicone before use.
How should PR-1205 be applied?
Apply it in a very light, even coat by wiping, dipping, or spraying, then wipe off any excess to avoid a white, chalky overapplication. Surfaces should be cleaned first and solvents allowed to evaporate before priming. The thin, uniform layer lets the silane react with and prepare the substrate.
How should PR-1205 be stored?
Because it is moisture-sensitive, keep the can tightly closed with minimal headspace and store below 32°C. Do not use material that has turned milky or shows white precipitate, which indicates moisture contamination. Pour small amounts for immediate use into clean, dry containers and discard leftovers.
