Technical Information

Typical technical information and properties of dielectric material for
flexible printed circuitry.

Technical Information
PropertyUnitsPolyimidePolymide (Adhesiveless)Polyester
Representative Trade NamePolyimidePolyimideMylar
Physical
Thickness Rangemil.5 to 51 – 60.025 to .5
Tensile Strength (at 25° C)psi25,00050,00020,000 to 35,000
Break Elongation%705060 to 165
Tensile Modulus (at 25° C)Tensile Modulus (at 25° C)4.3.75
Tear Initiation Strengthlb/in1000700 – 12001000 to 1500
Tear Propagation Strengthg/mil82012 to 25
Chemical
Resistance To:
Strong AcidsGoodGoodGood
Strong AlkalisPoorGoodPoor
Grease and OilGoodGoodGood
Organic SolventsGoodGoodGood
WaterGoodGoodGood
SunlightFairGoodGood
FungusNon-nutrientNon-nutrientNon-nutrient
Water Absorption (ASTM D570)% (24 hours)2.9.8< 0.8
Thermal
Service Temperature (min/max) Coefficient of Thermaldegree C-200/+300-200/ +350-60/+105
Expansion (at 22° C)PPM/ degree C202027
Change in Linear Dimensions (100° C, 30 min)%< 0.3 0.01 – 0.02< 0.5
Electrical
Dielectric Constant (ASTM D150) 1MHz3.43.43
Dissipation Factor (ASTM D150) 1MHz0.01.0030.018
Dielectric Strength (ASTM D149) @ 5 mil thickness Volume Resistivity (ASTM D257)V/mil
ohm-cm
3800
1.0E+16
6000
1.0E+16
3400
1.0E+16
Current Carrying Capabilities
Copper Weight
AMPS1/2 oz.
(0.0007″)
1 oz.
(0.0014″)
2 oz.
(0.0028″)
3 oz.4 oz.5 oz. 6 oz.7 oz.
Width in Inches
0.50.013″0.008″N/AN/AN/AN/AN/AN/A
1.00.028″0.017″0.013″N/AN/AN/AN/AN/A
1.50.040″0.027″0.020″N/AN/AN/AN/AN/A
2.00.053″0.040″0.030″0.0235″N/AN/AN/AN/A
2.50.080″0.060″0.042″0.0325″0.0285″N/AN/AN/A
3.00.100″0.083″0.057″0.045″0.0387″N/AN/AN/A
4.00.160″0.120″0.088″0.066″0.055″0.048″0.043″N/A
5.00.225″0.158″0.118″0.09″0.074″0.065″0.059″0.053″
6.00.285″ (off chart)0.195″0.153″0.117″0.094″0.082″0.074″0.0687″
7.0N/A (off chart)0.250″0.187″0.145″0.124″0.105″0.0905″0.082″
8.0N/A (off chart)0.307″0.232″0.180″0.1485″0.130″0.122″0.111″

This chart gives recommendations for width of conductor needed to carry current on different copper thickness.
Stripline Impedance
Dielectric ThicknessImpedance
204060
Conductor Width = W
0.002″0.007″0.004″N/A
0.003″0.012″0.006″0.003″
0.004″0.016″0.009″0.005″
0.005″0.021″0.0012″0.007″
0.006″0.026″0.015″0.008″
0.007″0.030″0.018″0.010″
0.008″0.0035″0.020″0.011″
0.009″0.039″0.023″0.013″
0.010″0.044″0.026″0.015″

Based on 1 oz. (0.0014″) copper conductors separated by polyimide, with a dielectric constant of 3.4 at 1 Mhz. These are for estimation only.

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