CC3-343 A & B
THERMALLY CONDUCTIVE EPOXY, CONFORMAL COATING
CC3-343 A & B is a unique dielectric coating that offers excellent heat transfer while providing exceptionally high electrical insulation. It is resistive to most chemicals for short time exposure. It is recommended for coating printed circuit boards and especially heatsink assemblies. The coating effectively distributes heat throughout the entire coated surface and can be easily applied using conventional spray equipment.
Thicknesses ranging from 1 to 6 mils can be applied in one coat. However, multiple coats are recommended when thickness of 5 mils or more are needed. (See curing instructions.)
CC3-343 is opaque so it offers excellent hiding power, cures dimple free, and provides excellent edge coverage. It meets the requirements of MIL-E-5272, will not peel or blister when exposed to 240 hours at 50'C and 96% relative humidity or 3 minutes immersion in a heat solder pot @ 330'C.
| SPECIFICATIONS: | ||
| UNCURED | ||
| Specific Gravity: @ 25 ' C | 1.3 - 1.4 | |
| Viscosity: @ 25 ' C, cps (uncatalyzed) | 100 - 300 | |
| Standard Color | Black | |
| Shelf Life: (months from manufacture date) | 12 | |
| PHYSICAL PROPERTIES | ||
| Tensile Strength: @ 25'C psi | 8,300 | |
| Tensile Elongation: % @ yield | 1.8 - 2.0 | |
| Compressive Strength: @ 25'C psi | 26,540 | |
| Izod Impact: ft lbs/in of notch | 0.35 | |
| Heat Distortion: ' C | 130 | |
| Water Absorption: 10 days @ 25 ' C, % | 0.2 | |
| Linear Shrinkage: in/in | 0.003 | |
| Service Temperature: 'C continuous | -65 to 130 | |
| Service Temperature: 'C intermittent | -100 to 230 | |
| Hardness: Shore D | 88 - 90 | |
| THERMAL PROPERTIES | ||
Thermal Conductivity: cal/sec-cm -'C/cm
x 10 |
26.2 | |
| Thermal Conductivity: BTU/ft-hr-'F/in |
7.7 | |
| Thermal Resistance: 'C in/watt | 35.6 | |
Coefficient of Thermal Expansion: in/in/'C
x 10 |
24 | |
| ELECTRICAL PROPERTIES | ||
| Volume Resistivity: @ 25'C, ohm-cm | 10 |
|
| Dielectric Constant: @ 25'C, 100 KC | 5.6 | |
| Dissipation Factor: @ 25'C, 100 KC | 0.02 | |
| Dielectric Strength: .003" thickness, volts | 1,000 - 2,000 | |
|
_Typical properties when cured for 2 hours: @ 65'C and 4 hours @ 135'C |
||
CC3-343 COMPARED WITH HARDCOAT,
MICA, and MYLAR:
1. Less than one third the cost of
Hardcoat
2. Low moisture absorption
3. Easily repaired if damaged
4. Higher thermal conductivity than Mica or Mylar in the same film thickness
5. Controllable film thickness
6. Impact and chemical resistant
7. No limitations as to size and shape
8. Can be applied to most metal surfaces
9. Faster transfer of heat from power devices to heatsink
SUGGESTED METHODS FOR APPLYING TRANSISTORS TO HEATSINKS:
Apply CC3-343 to the mounting surface of an extruded heatsink. Cure according to schedule. Apply Thermal Grease 800 to the base of the transistor. Secure the transistor to the coated mounting surface with either nylon or metal fasteners. The transistor is now completely electrically insulated from the heatsink.
The transistor can also be permanently bonded to the heatsink with CC3-341, an extremely thin glue line adhesive. A typical thermal resistance value of 0.143'C/watt can be achieved between the power device having an area of 1 sq. in. and a coated heatsink using a 3 mil coating and a 1 mil glue line.
SURFACE PREPARATION AND CURE:
Clean metal surfaces with a solvent wash. Untreated copper and aluminum, as well as nickel and stainless steel, should be primed with CC3-1295 Primer. For a majority of applications, a cure of 2 hours at 125'C (257'F) is adequate. For optimum physical and electrical properties an initial cure of 2 hours at 65'C (149'F) followed by a post cure of 4 hours at 135'C (275'F) is required. A shorter post cure of 2 hours at 150'C (302'F) is also satisfactory, but it is not recommended for colors other than black. Additional coats can be applied after an initial cure of 1 hour at 65'C (149'F) or after the coating has hardener but has not fully cured. The activated resin has a pot life of 24 hours or more in quart containers stored at 25'C (77'F).
MIXING INSTRUCTIONS:
Stir CC3-343 A thoroughly in its shipping container. For best results, use a commercial paint shaker or standard drill press and mixing blade. Weigh out the desired amount in a clean container and add 3.9 parts of CC3-343 B per 100 parts of CC3-343 A by weight. Mix thoroughly. No thinner is required.
(508) 587-4502 FAX (508) 587-4514
354 WEST STREET W. BRIDGEWATER, MA 02379