3M 421

3M 421 is backed with a rubber adhesive, offering excellent conformability in a variety of application conditions.

3M 421 Is an electrically and thermally conductive tape. This highly conformable tape resists flame, moisture, weather, UV degradation, chemicals, and radiation. The malleable tape can be shaped into complex or detailed patterns or die-cut into specific shapes。

Brand: 3M
Model No.: 421
Backing: Lead Foil
Adhesive: Rubber
Color: Dark silver
Backing thickness: 0.1mm
Total thickness: 0.17mm
Cutting: Any width
Die-cutting is available

Data Sheet

Features

Applications

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3M 421 Data Sheet

Property		Values
Backing	Lead Foil
Adhesive Type	Rubber (green)
Color	Dark Silver
Backing Thickness		0.1 mm (4 mil)
Test Method: ASTM D3652
Total Tape Thickness		6.6 mil (0.17 mm)
Test Method: ASTM D3652
Total Tape Thickness		0.17 mm
Test Method: ASTM D3652
Backing Thickness		4 mil
Test Method: ASTM D3652
Approximate Weight		28.4 g/m/24 mm (0.061 lb/yd/in)
Approximate Weight		0.061 lb/yd/in
Water Vapor Transmission		1.55 g/m²/24 hr (0.1 g/100 in²/24 hr)
Test Method: ASTM D3833
Water Vapor Transmission		0.1 g/100 in²/24 hr
Test Method: ASTM D3833
Typical Performance Characteristics
Property		Values
Tensile Strength		26.3 N/cm (15 lb/in)
Test Method: ASTM D3759
180° Peel Adhesion		4.9 N/cm (45 oz/in)
Test Method: ASTM D3330 Notes: 12 in/min (300 mm/min)
180° Peel Adhesion		45 oz/in
Test Method: ASTM D3330 Notes: 12 in/min (300 mm/min)
Tensile Strength		15 lb/in
Test Method: ASTM D3759
Elongation at Break		0.14
Test Method: ASTM D3759
Long Term Temperature Resistance		107 °C (225 °F)
Minimum Long Term Temperature Resistance		-51 °C (-60 °F)
Long Term Temperature Resistance		225 °F
Minimum Long Term Temperature Resistance Available Sizes		-60 °F
Property		Values
Standard Roll Length		33 m (36 yd)
Standard Roll Length		36 yd

3M 421 Features

Very good conformability.
Good thermal properties and will perform over a wide variety of temperature conditions (-60° to 225°F or -54° to 106°C). It has been used at higher temperatures for a shorter duration.
Electrically and thermally conductive.
Can be die-cut into specific shapes.
Elevated lead levels in water may result from long-term submersion of this product.
This material when disposed of separately is classified as RCRA hazardous waste. Please consult applicable Federal, State, and local regulations for proper disposal.
Best results are obtained when applied to a clean dry surface above 32°F (0°C). Also, by “feathering” the edges – rubbing the tape down with a smooth-edged plastic piece (or similar object) – the tape can be made to better conform to the substrate. This is especially important if the tape is to be used as a “thief” in electroplating where the edges must fully contact the metal base.