TOUGH-SEAL™ 21

TOUGH-SEAL™ 21 is a tough and durable fast gelling Potting Compound and Sealant with excellent Thermal Cycling Stability. This medium viscosity material is self-leveling and flows like honey around electrical components to ensure complete coverage of your entire PCB or electronic assembly.

TOUGH-SEAL™ 21 Properties

tough-seal label design
  • Fast gelling
  • Medium viscosity
  • 225% elongation
  • Shore Hardness: 64A
  • Excellent Thermal Cycling Stability from -40°F (-40°C) to 302°F (150°C)
  • Applications include: safety signal lighting, LED lighting, automotive sensors, wire harness assemblies, Printed Circuit Board Assembly,

Product Specifications: PC2021AB

TOUGH-SEAL™ 21 has a faster 10-20 minute working time and a Shore Hardness of 64A, which is similar to the hardness of a car tire. TOUGH-SEAL™ 21 reaches 94% of its full hardness after an overnight cure or with a heat cure of 1 hour at 80°C (176°F). TOUGH-SEAL™ does not exotherm or shrink during curing, therefore there is no embedment stress induced on the electronic components that could cause damage and failure of the PCB or electronic assemblies. Sensitive electronics can be potted safely with low embedment stress TOUGH-SEAL™.

With a high elongation of 225% when fully cured, TOUGH-SEAL™ 21 maintains exceptional flexibility and thermal cycling stability from –40°C to 150°C (-40°F to 302°F) without pulling back, wilting, or cracking. This ensures a tough seal that will stop moisture or other contaminants from damaging sensitive PCB’s and electronics.

TOUGH-SEAL™ has very aggressive adhesion to aluminum, making it a perfect choice for potting aluminum housings in LED lighting applications. TOUGH-SEAL™ bonds extremely well with most polymers. For housing and wire insulation materials that are exceptionally difficult to bond to, we offer our KEY PR1200 PRIMER, an aggressive adhesive promoter that is simple to use.

Technical Data Sheet (TDS) & Safety Data Sheet (SDS)

Tough-Seal Series

Physical Properties
21

Color, Part A

Off White

Viscosity at 25°C, cP, Part A, (RVT #5, 20 RPM)

7,000

Specific Gravityat 25°C, Part A

1.32

Color, Part B

Black

Viscosity at 25°C, cP, Part B, (RVT #5, 20 RPM)

11,000

Specific Gravity at 25°C, Part B
1.28
Density at 25°C, lbs/gal, Part B
10.7
Color, Mix
Grey / Black
Viscosity at 25°C, cP, Mix, (RVT #5, 20 RPM)
10,000
Specific Gravity at 25°C, Mix
1.29
Density at 25°C, lbs/gal, Mix
10.8
Mix Ratio by Volume
1A to 2B
Mix Ratio by Weight
51A to 100B
Gel Time at 25°C, Minutes, 100 grams
10
Shelf Life, Ambient, Part A Bulk (15°C to 35°C)
3 Months
Shelf Life, Ambient, Part B Bulk (15°C to 35°C)
12 Months
Shelf Life, Cold, Part A Bulk (-18°C to 3°C)
12 Months
Shelf Life, Cold, Part B Bulk (-18°C to 3°C)
12 Months
Electrical & Thermal Properties
21
Dielectric Strength, 25°C, Volts/mil
350
Volume Resistivity, 25°C, Ohm-cm x (10)12
1.20
Dielectric Constant, 25°C – 1 MHz
5.00
Dielectric Constant, 25°C – 1 kHz
5.50
Dielectric Constant, 25°C – 60 Hz
5.75
Dissipation Factor, 25°C – 1 MHz
0.026
Dissipation Factor, 25°C – 1 kHz
0.028
Dissipation Factor, 25°C – 60 Hz
0.064
Heat Capacity Cp, 25°C, J/g°K
1.37
Thermal Conductivity, 25°C, W/m°K
0.26
Coefficient of Thermal Expansion, ppm/°C
(-) 65°C to 75°C
135
75°C to 100°C
0
100°C to 150°C
75
Coefficient of Thermal Expansion, ppm/°F
(-) 85°F to 167°F
75
167°F to 212°F
0
212°F to 302°F
42
Click to View Chart
Hardness vs Temperature
21
(-75°C / -103°F)
88 A
(-25°C / -13°F)
75 A
5°C / 41°F
69 A
25°C / 77°F
64 A
50°C / 122°F
62 A
66°C / 150°F
61 A
80°C / 176°F
62 A
100°C / 212°F
57 A
120°C / 248°F
51 A
150°C / 302°F
47 A
Click to View Chart
Hardness vs Ambient Cure Time
21
1 Hour
15 A
2 Hours
26 A
4 Hours
31 A
8 Hours
35 A
12 Hours
35 A
1 Day
39 A
2 Days
46 A
3 Hours
52 A
4 Hours
57 A
1 Week
60 A
1 Month
68 A
Click to View Chart
Mechanical Properties
21
Tensile Strength per ASTM D638, 25°C, PSI
450
Elongation per ASTM D638, Type I, 0.125 in, 25°C
225%
Tensile Lap Shear Strength - per ASTM D1002, 25°C, psi *
Aluminum Bare
540 Co
Steel Bare
530 Ad
Steel Ground
480 Co
Primed Steel
530 Co
Galvanized Steel
560 Co
Tin Plated Steel
470 Co
Chrome Plated Steel
560 Co
Tensile Lap Shear Strength - per ASTM D3163, 25°C, psi **
FRP – Polyester Fiberglass
540 Co
Garolite G-9 Melamine/Glass
530 Co
Garolite G-10 Epoxy/Glass
550 Co
Garolite XX Phenolic/Paper
570 Co
Tensile Lap Shear Strength - per ASTM D3163, 25°C, psi **
Acrylic
560 Co
Acrylic/PVC
430 Co
PVC – Polyvinyl Chloride
530 Co
CPVC – Chlorinated PVC
660 Co
ABS – Acylonitrile Butadiene Styrene
500 Co
PETG – Polyethylene Terephthalate
610 Co
Lexan – Polycarbonate
520 Co
Nylon 6/6 – Polyamide
520 Co
Polypropylene
50 Ad
Polyethylene LDPE
20 Ad
Polyethylene HDPE
40 Ad
Teflon PTFE – Polytetrafluoroethylene
40 Ad
Noryl – Polyphenylene Oxide/Polystyrene
220 Ad
Ultem Polyetherimide
540 Co

Which TOUGH-SEAL™ PC is Right for you?

TOUGH-SEAL™ PC is a superior family of KEY sealants available in four standard formulations to fit a variety of potting applications. While all TOUGH-SEAL™ formulations are durable hybrid epoxy elastomers that grip and protect under the most aggressive conditions, they are available in a combination of properties that vary in hardness, gel-time, working time, and flow.

Order your TOUGH-SEAL™ Evaluation Kit Today!

Your Evaluation Kit will include everything you need to perform your own high quality product evaluation for your application.  No weighing or hand mixing.  Accurate delivery of material directly into your part.

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TOUGH-SEAL™ PC is bulldog tough and bred to grip and protect, under the most aggressive conditions.


Contact us for help selecting the correct TOUGH-SEAL™ PC for YOUR application!