DOWSIL™ 738 is a one-part, moisture-cure RTV silicone adhesive designed for room-temperature curing in environments with 30–80% relative humidity, eliminating the need for ovens and reducing energy and equipment costs. It develops over 90% of its physical properties within 24 to 72 hours, with initial handling possible in as little as 10 to 120 minutes depending on the application thickness. The adhesive cures from the exposed surface inward at a rate of approximately 0.25 inch per seven days, making it unsuitable for deep-section or confined-space applications. Mild heat below 60°C (140°F) may be used to accelerate cure and increase throughput. Once cured, it retains stable physical and electrical properties across a wide temperature range, enhancing the reliability and service life of PCB assemblies. Its robust chemistry and flexible processing support improved component safety, reduced total cost, and expanded performance margins for electronic devices and modules. UL 94 recognition applies based on minimum thickness, and certification details should be verified through the UL Online Certifications Directory.

• Non-Flowing Consistency - DOWSIL™ 738 maintains a stable, paste-like texture that prevents sagging and flow during vertical or overhead application. Tested according to ASTM C639, its flow rate remains below 3 mm, ensuring controlled placement and uniform joint coverage. This consistency allows precise application even in automated dispensing systems, maintaining bead stability until full cure.

  
  

• Room Temperature Cure - The adhesive cures efficiently at 23–25°C with relative humidity between 30–80%, eliminating the need for thermal curing. It achieves a tack-free surface within 90 minutes and develops 90% of its mechanical strength within 24–72 hours. This curing performance, verified through ISO 9046 evaluation, enables manufacturers to increase throughput and reduce operational energy costs.

  
  

• High Elongation - The cured silicone exhibits elongation of approximately 400%, confirmed through ASTM D412 tensile testing. This high elasticity allows it to absorb mechanical stress and vibration while maintaining seal integrity. The flexibility minimizes joint fatigue and prevents cracking during thermal expansion or structural movement.

  
  

• No Mixing Requirement - As a single-component RTV silicone, DOWSIL™ 738 does not require any mixing before use, reducing potential operator error. Its consistent composition ensures uniform cure and reliable performance across production batches. The single-part formulation also decreases material waste and simplifies storage and handling logistics.

  
  

• High Non-Volatile Content - With a non-volatile content of 96.1%, the sealant ensures minimal shrinkage during curing. This high solids level leads to dense, uniform films with superior mechanical stability and dimensional accuracy. The property contributes to enhanced bonding reliability and prevents void formation in critical sealing areas.

  
  

• Fast Processing Capability - The extrusion rate of 469 g/min allows rapid, continuous dispensing in automated production lines. Combined with a short tack-free time, this feature supports high-speed manufacturing environments requiring quick assembly cycles. It increases productivity and ensures consistent line efficiency without compromising bond quality.

  
  

• Long-Term Reliability - DOWSIL™ 738 retains its physical and chemical properties after extended exposure to humidity, oxidation, and light aging. After 1,000 hours in 95% relative humidity at 40°C, tensile strength decreased by less than 5%, confirming its resistance to environmental degradation. This ensures durable sealing performance in long-term industrial applications.

• Electronics Manufacturing - DOWSIL 738 is used for sealing and bonding components in electronic assemblies such as PCB modules and sensors. Its non-corrosive curing behavior protects conductive paths and ensures insulation reliability, while the moisture resistance maintains circuit protection in humid environments.

  
  

• Industrial Assembly - Applied in machinery production for sealing joints and gaskets under vibration and mechanical load. The 400% elongation and low shrinkage maintain sealing integrity, preventing leakage or detachment during prolonged operational stress in heavy-duty equipment.

  
  

• Automotive Components - Utilized in assembling vehicle electrical units and vibration-sensitive parts. The material’s consistent adhesion strength and mechanical stability minimize fatigue failure under high temperature and motion conditions, ensuring long-term sealing reliability.

  
  

• Appliance Production - Used for sealing and bonding metal and plastic components in ovens, dryers, and household devices. The white, non-sagging paste ensures neat joint formation, while room-temperature curing allows efficient in-line assembly without the need for post-curing heating processes.