Tough-Seal Performs

Tough-Seal is the KEY material for the electronic encapsulation of sensitive electrical components requiring premium thermal cycling performance, excellent thermal shock resistance, and outstanding environmental and corrosion protection.

  • Tough-Seal bonds exceptionally well to the walls of most plastic and metallic housings, frames and shells and stays in place without pull back during environmental exposure.
  • Tough-Seal has specific and aggressive aluminium adhesion. Specifying engineers love Tough-Seal on aluminum housings when standard potting compounds crack, pull away, or disbond.
  • For connectors, Tough-Seal adheres and seals to wire insulation and metal contacts and receptacles.
  • It is soft enough to deliver a resilient and durable potting but firm enough to lock down receptacles so they are not prone to push back upon plug insertion.
  • Tough-Seal is also now available in a higher viscosity formulation for glob-top encapsulating, allowing for localized potting and protection of vulnerable microelectronic components from environmental, mechanical & electrical damage.

Tough-Seal Superiority

Tough-Seal provides a unique combination of KEY properties not commonly found in just one potting compound.

If you use urethanes, Tough-Seal can extend your service temperature with an isocyanate-free solution that is not moisture sensitive.
If you use silicones, Tough-Seal offers a cost effective, non-silicone option with a friendly ratio and faster cure.
If you use epoxy, which is hard and rigid, Tough-Seal is an upgraded technology with exceptional flexibility that can withstand a wide range of service temperatures. With minimal exotherm, low shrinkage, and minimal expansion and contraction with temperature changes, Tough-Seal delivers low embedment stress, and outstanding thermal cycling performance.

Is Tough-Seal Right for Your Application?

Call Key Polymer now to find out, or order a kit & see for yourself.

Tough-Seal Properties

The physical, electrical, thermal and mechanical properties of all the Tough-Seal formulation can be compare below. These values are typical measurements and are provided as guide for specifying engineers. These values are not intended to be specifications.

Would you prefer to discuss your application with Tough-Seal Technical Service?
Email our team
or call 978-683-9411.
Harder Faster
Less Flow
Harder Slower
Less Flow
Softer Faster
More Flow
Softer Slower
More Flow
Physical Properties
Color, Part AOff WhiteOff WhiteOff WhiteOff White
Viscosityat 25°C, cP, Part A, (RVT #5, 20 RPM)7,0004,5003,5004,500
Specific Gravityat 25°C, Part A1.321.351.151.15
Densityat 25°C, lbs/gal, Part A11.
Color, Part BBlackBlackBlackBlack
Viscosityat 25°C, cP, Part B,
(RVT #5, 20 RPM)
Specific Gravityat 25°C, Part B1.
Densityat 25°C, lbs/gal, Part B10.710.78.58.5
Color, MixGrey / BlackGrey / BlackGrey / BlackGrey / Black
Viscosityat 25°C, cP, Mix, (RVT #5, 20 RPM)10,00011,0005,0006,000
Specific Gravityat 25°C, Mix1.291.311.071.07
Densityat 25°C, lbs/gal, Mix10.810.98.98.9
Mix Ratio by Volume1A to 2B1A to 2B1A to 2B1A to 2B
Mix Ratio by Weight51A to 100B53A to 100B57A to 100B57A to 100B
Gel Timeat 25°C, Minutes, 100 grams10601060
Shelf Life, See Product Information Bulletin (PIB) PIB PIB PIB PIB
Electrical & Thermal Properties
Dielectric Strength, 25°C, Volts/mil350350325350
Volume Resistivity,25°C, Ohm-cm x (10)121.203.752.101.75
Dielectric Constant,25°C – 1 MHz5.005.004.754.85
Dielectric Constant,25°C – 1 kHz5.505.455.205.25
Dielectric Constant,25°C – 60 Hz5.755.855.355.45
Dissipation Factor, 25°C – 1 MHz0.0260.0210.0240.025
Dissipation Factor, 25°C – 1 kHz0.0280.0340.0210.021
Dissipation Factor, 25°C – 60 Hz0.0640.0890.0440.043
Heat CapacityCp, 25°C, J/g°K1.371.421.751.80
Thermal Conductivity,25°C, W/m°K0.
seechart Coefficient of Thermal Expansion, ppm/°C
(-) 65°C to 75°C135145168200
75°C to 100°C00168200
100°C to 150°C75155168200
Coefficient of Thermal Expansion, ppm/°F
(-) 85°F to 167°F758193111
167°F to 212°F0093111
212°F to 302°F428693111
Hardness vs Temperature
seechart(-75°C / -103°F)88 A91 A87 A84 A
(-25°C / -13°F)75 A78 A50 A48 A
5°C / 41°F69 A70 A44 A43 A
25°C / 77°F64 A68 A37 A40 A
50°C / 122°F62 A66 A37 A41 A
66°C / 150°F61 A69 A37 A42 A
80°C / 176°F62 A68 A37 A42 A
100°C / 212°F57 A64 A37 A42 A
120°C / 248°F51 A54 A35 A41 A
150°C / 302°F47 A53 A33 A39 A
Hardness vs Ambient Cure Time


1 hour15 A0 A4 A0 A
2 hours26 A10 A6 A0 A
4 hours31 A17 A11 A0 A
8 hours35 A30 A14 A0 A
12 hours35 A35 A14 A0 A
1 day39 A48 A16 A9 A
2 day46 A56 A19 A23 A
3 days52 A61 A22 A28 A
4 days57 A65 A23 A31 A
1 week60 A65 A30 A35 A
1 month68 A71 A41 A43 A
Mechanical Properties
Tensile Strength
per ASTM D638, 25°C, PSI
450 550 800 850
per ASTM D638, Type I, 0.125 in, 25°C
225% 250% 400% 450%
Co=Cohesive Ad=Adhesive
Tensile Lap Shear Strength
per ASTM D1002, 25°C, psi **
metallicaAluminum Bare540 Co740 Co470 Co480 Co
Steel Bare530 Ad480 Ad260 Ad200 Ad
Steel Ground480 Co600 Co280 Ad200 Ad
Primed Steel530 Co560 Co150 Ad200 Ad
Galvanized Steel560 Co700 Co260 Ad200 Ad
Tin Plated Steel470 Co600 Co250 Co200 Co
Chrome Plated Steel560 Co490 Co250 Co200 Co
Tensile Lap Shear Strength
per ASTM D3163, 25°C, psi **
frp_textFRP – Polyester Fiberglass540 Co460 Co180 Ad210 Ad
Garolite G-9 Melamine/Glass530 Co620 Co130 Ad220 Ad
Garolite G-10 Epoxy/Glass550 Co690 Co130 Ad360 Ad
Garolite XX Phenolic/Paper570 Co520 Co190 Ad160 Ad
Tensile Lap Shear Strength
per ASTM D3163, 25°C, psi **
Thermoplastics_textAcrylic560 Co620 Co110 Ad300 Ad
Acrylic/PVC430 Co600 Co120 Ad250 Ad
PVC – Polyvinyl Chloride530 Co570 Co150 Ad250 Ad
CPVC – Chlorinated PVC660 Co670 Co170 Ad280 Ad
ABS – Acylonitrile Butadiene Styrene500 Co580 Co120 Ad180 Ad
PETG – Polyethylene Terephthalate610 Co610 Co100 Ad220 Ad
Lexan – Polycarbonate520 Co630 Co90 Ad210 Ad
Nylon 6/6 – Polyamide520 Co620 Co160 Ad260 Ad
Polypropylene50 Ad30 Ad40 Ad40 Ad
Polyethylene LDPE20 Ad0 Ad10 Ad10 Ad
Polyethylene HDPE40 Ad20 Ad40 Ad20 Ad
Teflon PTFE – Polytetrafluoroethylene40 Ad10 Ad20 Ad20 Ad
Noryl – Polyphenylene Oxide/Polystyrene220 Ad200 Ad170 Ad150 Ad
Ultem – Polyetherimide540 Co630 Co100 Ad170 Ad
**20 mil Bondline, 1 in x 4 in Adherands, 1 in Overlap