Datasheet

78
www.lairdtech.com
79
www.lairdtech.com
EMI ESSENTIALSEMI ESSENTIALS
INTRODUCTION TO ELECTRICALLY
CONDUCTIVE ELASTOMERS
OVERVIEW
The electrically conductive elastomers are based on dispersed
particles in elastomers, oriented wire in solid or sponge
elastomers, impregnated wire mesh screens or expanded metals.
They provide highly conductive, yet resilient gasketing materials
for EMI sealing as well as pressure and environmental sealing.
Conductive elastomers are used for shielding electronic
enclosures against electromagnetic interference (EMI). Usually,
the shielding system consists of a conductive gasket sandwiched
between a metal housing and lid. The primary function of these
gaskets is to provide sufcient electrical conductivity across
the enclosure/gasket/lid junction to meet grounding and EMI
shielding requirements, as well as prevent intrusion of the uids
into the electrical components.
Laird offers conductive elastomers in the following forms:
1. ElectroSeal dispersed ller particles in elastomers
2. ElectroMet oriented wire in solid and sponge elastomers,
and impregnated wire mesh and expanded metals
ELECTROSEAL™ GASKET INTRODUCTION
Conductive elastomer gaskets are EMI shielding and sealing
devices made from highly conductive, mechanically resilient and
conformable vulcanized elastomers. They are available in the
following types:
1. Flat gaskets or die-cuts
2. Molded shapes such as O-rings or intricate parts
3. Extruded proles or strips
4. Vulcanized-to-metal covers or anges
5. Co-molded or reinforced seals
6. Form-in-place gaskets
When any two at, but rigid surfaces are brought together,
slight surface irregularities on each surface prevent them from
meeting completely at all points. These irregularities may be
extremely minute, yet may provide a leakage path for gas or
liquid under pressure, and for high frequency electromagnetic
energy. This problem remains in ange sealing even when very
high closure force is applied.
However, when a gasket fabricated of resilient material is
installed between the mating surfaces, and even minimal
closure pressure is applied, the resilient gasket conforms to the
irregularities in both mating surfaces. As a result, all surface
imperfections and potential leak paths across the joint area
are sealed completely against pneumatic and uid pressure or
penetration by environmental gases. If the gasket is conductive
as well as resilient, with conductive matrix distributed
throughout its total volume in mesh or particle form, the joint
can be additionally sealed against penetration by, or exit of,
electromagnetic energy.
CONDUCTIVE TAPE
CONDUCTIVE FABRIC SHIELDING TAPE
Laird conductive fabric shielding tapes offer exceptional conformability and conductivity for dynamic flex applications. Conductive tapes are
constructed of nickel/copper metallized fabric with a conductive pressure sensitive adhesive (PSA). This reliable tape design provides outstanding
shielding performance while offering superior abrasion and corrosion resistance under high dynamic flex conditions.
Significant advantages over other fabric and foil shielding tapes include:
• Available UL510 flame rating.
• Thinner design provides superior flexibility and durability.
• High conductivity and shielding effectiveness.
• Adhesive system provides high peel strength.
• Easy die-cutting and processing.
• Superb adhesion of nickel copper plating.
• Eliminates the potential of injury due to the sharp edges
of metal foil tapes.
EMI shielding tape is available in standard roll widths from 0.394" (10 mm) to 3.937" (100 mm) in 0.197" (5 mm) increments and roll lengths
of 65.62' (20 M). Master rolls are available in sizes up to 1.0 meter widths and 20 meter lengths. For your unique design requirements, custom
die-cut parts are also available.
Some typical applications for EMI shielding tapes include:
• Shielding cables on notebook computers, copiers or other electronic equipment.
• “Fix-it” applications in test laboratories.
• Shielding over a component in which high conformability is essential.
• Shielding or grounding in weight sensitive applications.
• Shielding or grounding for electronic equipment where vibration may be present during operation.
TAPE CONSTRUCTION *
Carrier Nickel Copper Ripstop / Tafeta Fabric (1A)
Adhesive Conductive Pressure Sensitive Acrylic Adhesive
Liner Kraft Paper
PERFORMANCE CHARACTERISTICS *
Conductive Tape Thickness
0.005 ± 0.0008 inches
(0.13 ± 0.02 mm)
Tensile Strength (ASTM D5035) 50 lb / in.
Weight (LT 500)
2.9 oz./sq. yard
(100 grams/sq. Meter)
XY Sheet Resistivity
(ASTM F390)
< 0.03 ohms/sq.
Peel Strength 28 oz./in. (8.7 N/25 mm)
Abrasion Resistance
(ASTM D3886)
> 750,000 Cycles
Temperature Range 32°F to 176°F (0°C to 80°C)
Max. Temperature (short term) 120°C
Shielding Effectiveness
100 MHz @ 70 dB
1 GHz @ 80 dB
3 GHz @ 90 dB
Z-Axis Resistivity < 0.040 ohms
Shelf Life 6 months @ 23°C, 60% R.H.
* Properties for standard tapes. Other tape properties available upon request.
ORDERING INFORMATION:
86-726 Standard Tape
86-785 Standard Tape
86-203 Black Tape
86-205 Black Tape
87-580 UL510 Rated
DS005 Double Sided Tape
D6-785FX Double Sided Tape
76-750 Thin Tape