DOWSIL 732 MULTI-PURPOSE SEALANT

Harmonization Code : 3506.91.90.99 | Prepared glues and other prepared adhesives, not elsewhere specified or included; products suitable for use as glues or adhesives, put up for retail sale as glues or adhesives, not exceeding a net weight of 1 kg ; Adhesives based on polymers of headings 3901 to 3913 or on rubber; Other ; Other

DOWSIL 732 MULTI-PURPOSE SEALANT

Main features

  • One-Part Moisture-Cure Sealing
  • Thermal Stability for Sealing
  • Non-Sag Placement Control

Product Description

DOWSIL™ 732 Multi-Purpose Sealant is a one-part, general-purpose silicone adhesive and sealant. It utilizes an acetoxy cure system to cure at room temperature when exposed to atmospheric moisture, forming a tough, flexible rubber. Available in white, black, clear, and aluminum, it features a non-sag paste consistency that makes it easy to apply for various bonding and sealing needs.

Product Key Features

  • One-Part Moisture Cure - cures at room temperature upon exposure to moisture in the air, offering a skin-over time of 7 minutes and a tack-free time of 20 minutes.
  • Thermal Stability - remains stable and flexible from -60°C to +180°C, with short peaks up to +205°C[cite: 1595, 1596]. The black version offers extended stability up to +205°C, with short peaks up to +230°C.
  • Mechanical & Electrical Profile - delivers a Shore A hardness of 25, a tensile strength of 2.3 MPa, an elongation of 540%, and excellent dielectric properties.
  • Regulatory Compliance - complies with MIL-A-46106 and FDA 177.2600 specifications.
  • Non-Sag Rheology - maintains a non-slump paste consistency, ensuring it remains in place during application.

Applications

This sealant is ideal for general industrial sealing and bonding applications where a durable, flexible rubber seal is required.

  • General Industrial Bonding - provides good, unprimed adhesion to many substrates such as glass, metals, and most common engineering plastics.
  • High-Temperature Environments - suitable for assemblies experiencing extreme temperature fluctuations requiring continuous thermal stability.
  • Regulated Applications - can be confidently used in settings requiring compliance with FDA 177.2600 or MIL-A-46106 standards.

Technical Specifications

General Properties
ColorColor
White, black, clear or aluminum
Specific GravitySpecific Gravity
1.04
Physical Properties
ViscosityViscosity
821,000 mPa.s
Mechanical Properties
ElongationElongation
540 %
Physical Properties
Skin TimeSkin Time
7 minutes
Tack-Free TimeTack-Free Time
20 minutes
Electrical Properties
Dielectric StrengthDielectric Strength
21.6 kV/mm
Volume ResistivityVolume Resistivity
1.5e15 Ohms⋅cm

Additional Information

General Purpose Silicone Adhesive / Sealant

DOWSIL™ 732 Multi-Purpose Sealant

DOWSIL™ 732 Multi-Purpose Sealant is a premier one-part silicone adhesive and sealant engineered for a diverse range of general industrial sealing and bonding applications. Operating via an acetoxy moisture-cure mechanism, this non-sag paste cures efficiently at room temperature upon exposure to atmospheric moisture, transforming into a tough, highly flexible silicone rubber. It provides excellent dielectric properties, stable performance across wide temperature configurations, and robust unprimed adhesion to many common substrates. Fully compliant with military specification MIL-A-46106 and FDA 177.2600 regulations, it ensures long-term joint reliability for demanding manufacturing and maintenance frameworks.

One-part moisture cure 7 min skin-over time MIL-A-46106 Compliant FDA 177.2600 Compliant
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Typical values only. Performance metrics are measured following full moisture activation under standard room temperature settings.

DOWSIL 732 Multi-Purpose Sealant product package
DOWSIL™ 732 Multi-Purpose Sealant

Key Features

  • One-part RTV formulation requires no pre-mixing equipment, optimizing factory process lines and minimizing waste.
  • Thixotropic non-sag paste consistency tracks cleanly and stays in place on vertical or overhead joints.
  • Cures to a tough, highly flexible silicone rubber capable of resolving substrate thermal expansion differentials.
  • Excellent unprimed adhesion profiles over glass, ceramics, common metals, and engineering plastics.
  • Outstanding dielectric performance parameters coupled with high volume resistivity (1.5x10¹⁵ Ohm-cm).
  • Certified to meet military specification MIL-A-46106 and FDA 177.2600 food-contact criteria.

Processing Summary

Color Assortment: Produced in a versatile industrial palette of white, black, clear, and aluminum variants to perfectly coordinate with design aesthetics.
Skin-Over & Tack Windows: Surface skin formation starts rapidly in 7 minutes at 25°C. Transitions to a complete tack-free state within 20 minutes. Tooling should be completed with a spatula before skinning occurs.
Inward Cure Progress: Cross-linking moves inward from the exposed surface at 25°C and 50% RH, achieving a cure depth of roughly 3 mm within 24 hours. Confinement or lower humidity extends this duration.
Thermal Endurance Profiles: Standard configurations maintain flexibility from -60°C to 180°C with short peaks to 205°C. The black version delivers enhanced resistance from -60°C to 205°C with peaks to 230°C.
Handling and Application Guidance

Process Notes 

Storage and Shelf Life
  • Store raw materials at or below 32°C (90°F) in original, unopened containers.
  • Keep containers tightly closed when not in use, as the product cross-links via reaction with air moisture.
  • A cured plug of material may form in the nozzle tip during storage; this is easily removed and does not harm contents.
  • Track stock rotation based on the formal "Use Before" date printed on the container labels.
Surface Preparation
  • Joint boundaries must be completely clean and dry prior to sealant extrusion.
  • Degrease and clear contaminants using isopropyl alcohol, acetone, or methyl ethyl ketone (MEK).
  • While unprimed adhesion is excellent on glass and metals, it will not normally bond to PTFE, PE, or PP.
  • For maximum adhesion, wipe with solvent, then apply a thin coat of DOWSIL™ 1200 OS Primer and let dry for 15-90 minutes.
Substrate Compatibility Note
  • The acetoxy cure chemistry releases a small amount of acetic acid vapor as a by-product during vulcanization.
  • This acetic acid byproduct can potentially cause corrosion on certain sensitive metallic parts or sub-assemblies.
  • Avoid processing this sealant inside totally enclosed or confined configurations where vapor by-products cannot escape.
  • Before handling and packaging parts, allow a sufficiently long dwell time to protect adhesive seal integrity.
Typical Properties

Engineering Data for DOWSIL™ 732

Uncured Physical Properties 

Physical Property Typical Engineering Value Corporate Test Method (CTM) / Condition
Appearance Non-slump paste CTM 0176
Color Assortment White, black, clear, or aluminum CTM 0176
Extrusion Rate 350 g/minute Measured using 3.2 mm orifice at 0.62 MPa (CTM 0364)
Viscosity (Low Shear - 1/s) 821 Pa-sec CTM 1377
Viscosity (High Shear - 10/s) 168 Pa-sec CTM 1377

Cured Mechanical & Electrical Properties

Properties measured following a full 7-day cure in air at 25°C (77°F) and 50% relative humidity.

Elastomeric Parameter Typical Engineering Value Test Standard Basis (ASTM / CTM)
Specific Gravity 1.04 ASTM D1475 / CTM 0097B
Durometer Hardness 25 Shore A ASTM D2240 / CTM 0099
Tensile Strength 2.3 MPa ASTM D412 / CTM 0137A
Elongation at Break 540 % ASTM D412 / CTM 0137A
Volume Coefficient of Thermal Expansion 1.12 x 10⁻³ 1/K CTM 0420
Dielectric Strength 21.6 kV/mm ASTM D149 / CTM 0114
Dielectric Constant (Permittivity) 2.8 Evaluated at 100 Hz to 100 kHz (ASTM D150 / CTM 0112)
Dissipation Factor 0.0015 Evaluated at 100 Hz to 100 kHz (ASTM D150 / CTM 0112)
Volume Resistivity 1.5 x 10¹⁵ Ohm-cm ASTM D150 / CTM 0112
Applications

Where DOWSIL™ 732 Fits

General industrial factory sealing and component bonding
Industrial Sealing & Bonding
Perfect for a vast array of general multi-material manufacturing joins and maintenance procedures across production facilities.
  • Ready-to-use general purpose silicone paste adhesive.
  • Bonds tight to glass, metals, and engineering plastics.
  • Easy toolability with a spatula for neat, aesthetic beads.
Regulated industrial equipment assembly sealing
Regulated Assemblies
Extensively tested and recognized under international agency standards to support highly specific defense and commercial guidelines.
  • Fully complies with military standard MIL-A-46106.
  • Meets strict FDA 177.2600 food-contact criteria.
  • Ensures strict material tracking and verified compliance.
Flexible thermal expansion stress relief sealing
Thermal & Flexible Joints
Forms a tough, flexible rubber skin with 540% elongation to accommodate structural movements and mechanical vibrations.
  • Excellent environmental sealing and moisture blocking.
  • Dielectric breakdown protection tracks at a strong 21.6 kV/mm.
  • Absorbs relative shifting between dissimilar joint materials.
Product Demo

See One-Part Moisture-Curing Silicone Paste Dispensing Methods

Observe the high-precision processing of one-part non-flowing general-purpose silicone adhesive sealants via automated needle dispensing setups. This practical reference highlights best practices for balancing track extrusion parameters, checking non-slump bead profiles, and verifying surface handling stability before complete room temperature cross-linking completes.

Package & Support

Standard Packaging & Technical Help

Standard Packaging
  • Available across multiple standard industrial container net weight classes.
  • Supplied ready-to-use for direct extrusion without multi-part manual blending steps.
  • Packaging configurations safeguard raw material against air moisture contamination.
Technical Help Capabilities
  • Assisting manufacturing loops with room-temperature setup to bypass thermal oven operating costs.
  • Evaluating substrate material groups to optimize unprimed dính bám on engineering plastics.
  • Configuring automated needle dispensing parameters to coordinate with the specified 350 g/min extrusion rate.
  • Providing formal compliance certificates and safety parameters verifying MIL and FDA approvals.
Technical Guidance

Tips and Troubleshooting

Issue Recommended Action
Premature layer skinning or surface tearing during finishing tooling steps
  • Surface skin over progresses fast, typically commencing within 7 minutes at standard parameters.
  • Ensure any smoothing adjustments or spatula profiling operations are completed before the surface skin initializes.
  • Perform assembly line joins immediately after application to guarantee complete adhesive transfer across boundaries.
Incomplete structural cross-linking down through joint core zones
  • One-part moisture cure chemical cross-linking relies strictly on atmospheric moisture and progresses inward from the exterior skin.
  • Do not utilize this multi-purpose product in highly confined or enclosed pockets lacking proper air access.
  • Be aware that deep-section cure dimensions advance at an approximate depth tracking rate of 3 mm per 24 hours.
  • Expect extended cure tracking behaviors if the plant floor surrounding relative humidity indices fall low.
Adhesion tracking breakdown or low lap shear force values over difficult substrates
  • Unprimed structural bonds will not stick successfully onto non-reactive substrates like Teflon, polyethylene, or polypropylene.
  • Highly plasticized plastics or rubbers can leach mobile components over time, which function as active release agents.
  • Verify all targets are cleanly washed of mill fluids or grease using isopropyl alcohol, acetone, or MEK.
  • Apply specialized surface configurations such as chemical etching, inline plasma treatment, or compatible DOWSIL™ Primers.
Next Steps

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