Gap Pad V0 is a thermally conductive
material that acts as a thermal interface
between a heat sink and an electronic
device. The conformable nature of Gap
Pad V0 allows the pad to fill in air gaps
between PC boards and heat sinks or a
metal chassis.
Gap Pad V0 is a highly conformable,
low modulus polymer on a fiberglass carrier.
The material is available in thicknesses
from .020” to .160” with a liner applied to
the pink side of the material. The range in
thicknesses and the materials flexibility
allow Gap Pad V0 to be used in a variety of
applications where surface textures vary and
the space between surfaces is uneven. The
material is available in die-cut parts and
with or without adhesive.
Applications
• Areas where heat needs to be transferred
to the frame or other type of heat spreader
• Between a CPU and a heat spreader
• Between a semiconductor and heat sink
• Replacement for messy grease
U.L. File Number E59150
Die-Cut parts, and Sheets
Gap Pad is available in die-cut parts and
sheets. Standard sheet size is 8" x 16". Gap
Pad is not available in rolls.
MODULUS * The modulus of Gap Pad is shown as being rate dependent because Gap Pad is
viscoelastic. At high rates of compression Gap Pad is elastic and at low rates it is viscous. Elastic strain is
instantaneous, independent of time. The total deformation occurs at the instant the stress is applied and
is completely recovered when the stress is released. Viscous strain is time dependent. The deformation
is not instantaneous but occurs over time and is not completely recovered after the stress is removed. As
an example, if the low modulus Gap Pad rubber is molded into a ball and dropped on the floor it will
bounce. However, if a load is placed on the ball for a long period of time it will flatten out to a certain
extent and will not recover completely to it's original shape after the load has been removed.
THERMAL RESISTANCE ** With Gap Pad, the thermal resistance is dependent on the gap
between the device and the heatsink. The engineer can minimize the thermal resistance by
designing the gap as small as possible. A Gap Pad thickness is then chosen to be just thick enough
to fill the largest gaps while minimizing the deflection needed in the smallest gaps to decrease the
stress exerted on the devices. If the size of the gaps are known, the thermal resistance across each
gap is determined from the table of thermal resistance vs. thickness.
GAP PAD VO™
Conformable, Thermally Conductive Material for Filling Air Gaps
Property Value Value Test Method
Mechanical Properties
Thickness inches .020” to .160” ASTM D374
Color Yellow/Pink Visual
Specific Gravity 1.6 ASTM D792
Heat Capacity J/g-K 1 ASTM C351
Continuous Use -60 to +200C
Hardness, entire composite vs. Thickness (in) (Type 00) ASTM D2240
0.020 80
0.040 65
0.060 65
0.080 55
0.100 50
0.125 45
0.160 40
Young's Modulus (psi) Rate Modulus ASTM D575
vs. Rate of Strain 0.01 200
(inches/minute)* 0.1 300
Area = 0.5 in21.0 400
Low Modulus Portion Only 10.0 800
Stress vs. strain and resultant deflection in mils for each Gap Pad V0 thickness.
Example: Rate = 1 in/min. Modulus = stress/strain = 400 psi, Area = 0.5 in2, Low Modulus Portion Only;
Stress Strain 20 mil 40 mil 60 mil 80 mil 100 mil 125 mil 160 mil
4 psi 1% 0.15 0.35 0.55 0.71 0.91 1.16 1.51 ASTM D575
8 psi 2% 0.30 0.70 1.10 1.42 1.82 2.32 3.02
20 psi 5% 0.75 1.75 2.75 3.55 4.55 5.80 7.55
40 psi 10% 1.50 3.50 5.50 7.10 9.10 11.6 15.1
80 psi 20% 3.00 7.00 11.0 14.2 18.2 23.2 30.2
200 psi 50% 7.50 17.5 27.5 35.5 45.5 58.0 75.5
Electrical Properties
Dielectric Constant 5.5 ASTM D150
Dielectric Breakdown Voltage kV-AC >6 ASTM D149
Volume Resistivity, Ohm-meters 1011 ASTM D257
Thermal Properties
Thermal Conductivity @ 10 psi, W/m-K 0.8 ASTM D5470
Thermal Resistance** vs. Thickness (in.) (C-in2/W)
Entire composite 0.020 1.0 ASTM D5470
0.040 2.0
0.060 3.0
0.080 4.0
0.100 5.0
0.125 6.2
0.160 8.0
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