Acetoxy Silicone Sealant

Medium/high modulus acetoxy silicone sealant


  • High strength
  • Good elasticity
  • Conforms to ISO 11600-F&G-20LM
  • Resistant to ozone, ultra-violet radiation and temperature extremes

DOWSIL 781® Acetoxy Silicone Sealant is a one-part, silicone sealant which has good adhesion to a range of non-porous surfaces including glass, aluminum, painted surfaces and composite boards. It offers excellent resistance to aging, shrinkage, cracking and discoloring. It is also approved in certain countries for use in contact with potable water once cured.

Typical Properties

Specification Writers: These values are not intended for use in preparing specifications. Please contact your local DOWSIL sales office or your Global DOWSIL Connection before writing specifications on this product.

Test Method1 Property Unit Value
  Cure system   Acetoxy
  Application temperature °C
CTM 97B  Specific gravity   1.02
CTM 364C Extrusion rate g/minute 220
CTM 98B Skin-over time (23°C or 73°F, 50% R.H.) minutes 14
CTM 663A Cure rate (23°C or 73°F, 50% R.H.)    
1 day mm 3
3 days mm 5
2mm thickness S2 dumb-bells (ISO 37)
CTM 137A E-Modulus 100% MPa 0.40
CTM 137A Tensile strength MPa 1.8
CTM 137A Elongation at break % 520
 12x12x50mm size T.A. joint (ISO 8339/DIN2-8339)
CTM 677 E-Modulus 100% MPa 0.4
CTM 677 E-Modulus 60% MPa 0.35
CTM 677 Tensile strength MPa 0.59
CTM 677 Elongation at break % 190
CTM 99E Hardness (Shore A)   22
ISO 9047 Joint movement capability % 20
1. CTM: Corporate Test Method, copies of CTMs are available on request.
DIN: Deutsche Industrie Norm.
ISO: International Standardisation Organisation.


Technical Specifications & Standards

Conforms to ISO 11600-F&G-20LM. Listed by the UK Water Fittings Byelaws Scheme for use in contact with potable water, once cured.

Handling Precautions

Product safety information required for safe use is not included. Before handling, read product and safety data sheets and container labels for safe use, physical and health hazard information. The material safety data sheet is available on the DOWSIL website at You can also obtain a copy from your local DOWSIL sales representative or Distributor or by calling your local DOWSIL Global Connection.

Usable Life & Storage

When stored in cool, dry conditions below 30°C (86°F) in the original unopened containers, DOWSIL® 781 Silicone Sealant has a usable life of 27 months from the date of production.


DOWSILTM 781 Silicone Sealant is supplied in 310ml cartridges packed in boxes of 12.


DOWSILTM 781 Silicone Sealant is not recommended for use on porous substrates such as concrete, stone, marble or granite.

DOWSILTM 781 Silicone Sealant should not be used in contact with the edge seal of an insulated glazing unit.

Do not use DOWSILTM 781 Silicone Sealant on bituminous substrates, substrates based on natural rubber, choloroprene or EPDM, or on building materials and flexible plastics which might bleed oils, plasticizers, or solvents.

Do not use DOWSILTM 781 Silicone Sealant in a totally confined space because the sealant requires atmospheric moisture to cure. Because acetic acid is released during curing, it can corrode mirror silver and sensitive metals such as copper, brass and lead. DOWSILTM 781 Mirror Adhesive should be used for this application.

DOWSILTM 781 Silicone Sealant is not recommended for use on submerged joints, or in joints where physical abuse or abrasion is likely to occur.

DOWSILTM 781 Silicone Sealant is not suitable for food contact applications. However, it has been listed by the UK Water Fittings Byelaws Scheme for use in contact with potable water, once cured.

DOWSILTM 781 Silicone Sealant has not been designed for use as an aquarium sealant.

DOWSILTM 781 Silicone Sealant is not recommended for structural glazing or insulated glazing applications.

DOWSILTM 781 Silicone Sealant is not recommended for structural glazing or insulated glazing applications. This product is neither tested nor represented as suitable for medical or pharmaceutical uses.

Health & Environmental Information

To support Customers in their product safety needs, DOWSIL has an extensive Product Stewardship organization and a team of Product Safety and Regulatory Compliance (PS&RC) specialists available in each area.

For further information, please see our website, or consult your local DOWSIL representative.

Limited Warranty Information – Please Read Carefully

The information contained herein is offered in good faith and is believed to be accurate. However, because conditions and methods of use of our products are beyond our control, this information should not be used in substitution for customer’s tests to ensure that DOWSIL’s products are safe, effective, and fully satisfactory for the intended end use. Suggestions of use shall not be taken as inducements to infringe any patent.

DOWSIL’s sole warranty is that the product will meet the Dow Corning sales specifications in effect at the time of shipment.

Your exclusive remedy for breach of such warranty is limited to refund of purchase price or replacement of any product shown to be other than as warranted.


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Important Note

This data sheet is issued as a guide to the use of the product(s) concerned. Whilst a.b.e.® Construction Chemicals endeavors to ensure that any advice, recommendation, specification or information is accurate and correct, the company cannot – because a.b.e.® has no direct or continuous control over where and how a.b.e.® products are applied – accept any liability either directly or indirectly arising from the use of a.b.e.® products, whether or not in accordance with any advice, specification, recommendation, or information given by the company.

Further Information

Where other products are to be used in conjunction with this material, the relevant technical data sheets should be consulted to determine total requirements. a.b.e.® Construction Chemicals has a wealth of technical and practical experience built up over years in the company’s pursuit of excellence in building and construction technology.

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