Product details ▾
  • Provides a high compression flexible gasket between mating flanges in ductwork when manufactured to B&ES DW/144 Second Edition 2013 Classes A, B, and C
  • Is a pre-formed strip of 100% butyl rubber compound which assures virtual airtight joints
  • It bonds immediately to the mating flanges without slippage or movement
  • Will yield without breaking its seal when ductwork is prone to movement, particularly during erection and when under increased limits of pressure during air leakage testing procedures

Available Sizes

• Type 20 – 9mm x 4mm x 10m Roll

• Type 30 – 15mm x 4mm x 10m Roll



A 100% solids, polymeric, butyl sealant material


Aggressive Tack – assures positive positioning and maximum surface contact.

Stable Configuration – will conform to surface undulations and irregular joint areas, yet is not easily displaced under compression.

Chemical Permanency – Low level of chemical reactivity is reflected as water resistance, UV resistance, non-corrosivity to metals, paint acceptance and the flexible retention critical to joints subjected to movement, dimensional shock and racking. Compatibility with most plastics, foams and rubber as well as painted and unpainted metal surfaces is excellent.

Use- A sealant may be considered as a void-filling adhesive, Ductmate 440 tape was developed to provide a tough durable metal lap joint seal against the ingress of water, dirt and the like. Typical applications include sealing of duct flanges and laps in ductwork.

Performance Properties

Solids: 99 +/- 1%
Colour: Off White
Specific Gravity: 1.40 +/- 0.15
Odour: Negligible
Shelf Life: 12 Months Minimum
Service Life: 20 Years Minimum
Service Temperature: -50 ºC to 105 ºC


Tensile value of 0.09-0.12 N/mm2 Cohesive at 25 C and compressed to 50% (at the rate of 50mm/minute – Instron).


Infinite at room temperature; excellent at low temperature. (No cracking or loss of adhesion to steel substrate at 40ºC when bent 180  within two seconds around a 12mm dia mandrel).

Elongation / Webbing

Passes. (Test requires material supports a head of water approximating 20 KN/m2 at 300% to 800% elongation).

25ºC – In excess of 800% with a continuous film.

-15ºC – A continuous film in excess of 200% (water frozen) and 300% at water thaw.


ASTM Test Method D 217 is used to determine the degree of softness. This involves evaluation of the sealant at low temperatures; workability and handling properties at high temperatures.

Conditions Range Typical
-15ºC/300 grams/5 secs 40 Minimum 50
25ºC/300 grams/ 5secs 115 Maximum 110
50ºC/300 grams/5 secs 145 Maximum 142


Dimensional Stability

Will not flow, slump, or drip at elevated temperatures (105 ).

Ultra-Violet/ Humidity

Retains excellent flexibility and exhibits no adhesion loss or appreciable hardening following exposure in an Atlas Twin Arc Weatherometer in excess of 3000 hours. (Cycel 102 minutes at high intensity UV followed by 18 minutes of high intensity UV combined with a water spray at a black panel temperature of 60ºC.


Retains excellent flexibility with no apparent loss of adhesion to galvanised steel, aluminium or painted substrates. (sandwiched panels compressed to 1.5mm and aged for one year at 90ºC).


No evidence of darkening, surface etching or salt deposition following contact with aluminium, galvanised steel or copper (90ºC, at 100% relative Humidity for 7 days).


No evidence of surface staining of painted substrates (UV exposure of 24 hours).

Plasticiser Migration

No visible “bleed out”. (Metal to glass sandwich compressed 50% and placed in an oven for 24 hours at 105ºC).

Water Resistance

No evidence of softening, adhesion loss or other adverse effects noted following immersion in water at ambient temperature.


MIL-C-18960B, Type II, Class B equals or exceeds performance requirements.

MBMA – Ice Damming / Static Water Head Test – passes both simulated laboratory test and full field tests.