Prime Coats: Choosing the Right Silicone Primer
Prime Coats: Choosing the Right Silicone Primer
A silicone sealant or adhesive can only perform as well as its bond to the surface beneath it. Some silicones adhere to common materials without a primer, while other combinations of silicone and substrate benefit from an adhesion-promoting prime coat. Choosing one starts with two questions: What are you bonding to, and which silicone are you using?
Lentus offers several DOWSIL™ primers and prime coats for different surfaces and silicone systems. Here’s how to narrow the options.
Start with the surface
Identify the material on each side of the bond, including any paint, finish, or coating. A metal surface, for example, may need a different approach once it has been painted. Before priming, make sure the surface is clean and dry, and follow the product instructions for application and drying time. Applying more primer than directed can interfere with adhesion. Test the complete primer, silicone sealant or adhesive, and substrate combination before production or installation.
Primer curing times vary depending on the product, temperature, and humidity. Low-humidity and/or low-temperature conditions may require longer cure times. Mild heat may help accelerate curing, but temperatures above 140°F (60°C) are not recommended.
During application, the carrier solvent typically evaporates quickly, allowing the active ingredients to begin reacting with atmospheric moisture and bonding surfaces. Follow the manufacturer’s recommended curing instructions and allow the primer to fully cure before applying the silicone sealant or adhesive.
Compare DOWSIL™ Silicone Primers and Prime Coats
DOWSIL™ PR-1200 RTV Prime Coat
A clear, naphtha-based general-purpose primer designed for use with silicone elastomers and RTVs. It promotes adhesion of silicone sealants, coatings, and rubber to a wide variety of substrates.
APPLICATIONS:
- Silicone elastomers and RTVs
- Certain one-part silicone sealants and coatings
- Masonry, wood, granite, metals, glass, ceramics, plastics, rubbers, and coatings
- Battery packs
- Boards and assemblies
- Components
- Housings
FEATURES:
- One-part formulation
- Enhances adhesion of moisture-cure RTV and heat-cure silicones
- Can be applied by wiping, dipping, or spraying
- Water resistant
Designed to improve the quality and speed of adhesion development for RTV silicone sealants on many nonporous substrates.
APPLICATIONS:
- Moisture-curing RTV and heat-curing silicones
- Ceramics, glass, wood, masonry, structural plastics (including FR-4), and many metals
- Battery packs
- Boards and assemblies
- Components
- Connectors
- Engine systems
- Housings
FEATURES:
- Adhesion enhancing, colorless primer dispersed in heptane
- Diluted in low-molecular-weight silicone fluid
- Meets many international regulations for low VOC content (including European Union)
Clear, film-forming option formulated to increase adhesion of RTV silicones to harder-to-bond plastics, as well as many metals and ceramics.
APPLICATIONS:
- Battery packs
- Boards and assemblies
- Components
- Housings
FEATURES:
- Adhesion-enhancing, clear primer dispersed in a mixture of organic solvents for use with many RTV silicones
- Enhances bonding/adhesion of RTV silicones to many metals, ceramics, and plastics
- Specially formulated to increase adhesion of a wide range of silicones to plastics, including more difficult types such as acrylic and polycarbonate
DOWSIL™ PR-1204 RTV Prime Coat
Clear primer in naphtha solvent for use with all one-part alcohol-cure and two-part condensation-cure silicone elastomers.
APPLICATIONS:
- One-part alcohol cure
- Two-part condensation cure silicone elastomers
- Metals, ceramics, glass, and masonry
- Battery packs
- Boards and assemblies
- Components
- Housings
FEATURES:
- Enhances bonding/adhesion of RTV and heat-cure silicones
- Water resistant
A clear, one-part primer designed to enhance adhesion of many moisture-curing RTVs and heat-curing silicones to a variety of surfaces.
APPLICATIONS:
- RTV and heat cure silicones
- Glass, metals, and plastics
FEATURES:
- One-part formulation
- Adhesion-enhancing primer dispersed in heptane
- Can be applied by wiping, dipping, or spraying
DOWSIL™ PR-2260 RTV Prime Coat
Designed to enhance adhesion of RTV and heat-cure silicones to many metals, ceramics, and some plastics. It also offers oil resistance. Confirm the specific substrate and service conditions before selecting.
APPLICATIONS:
- RTV and heat-cure silicones
- Metals, ceramics, and some plastics
- Battery packs
- Boards and assemblies
- Components
- Housings
FEATURES:
- Adhesion enhancing
- Oil resistant
Find the Right Silicone Primer with Lentus
The right prime coat depends on the substrate, silicone cure system, and conditions the finished bond will face. Explore Lentus’s selection of DOWSIL™ cleaners, coatings, and primers or contact the Lentus team at Sales@LentusLLC.com or +1 270-765-2212.
