Magnolia Plastics
Electrically & Thermally Conductive Compound
Magnobond 3360, Parts A & B

Plastics for the Space Age Since 1957


Magnobond 3360, Parts A & B

DESCRIPTION

Magnolia 3360, Parts A & B, is an unfilled epoxy system for encapsulating electronic circuitry in a sand-filled aluminum container. At 85° C, this system is extremely fluid and will replace the air from the unit. For 6 to 8 minutes at 85° C, this fluid condition will prevail, wetting the walls of the housing and allowing trapped air to migrate to the surface. The low surface tension of Magnolia 3360 promotes easy bubble breaking and generally provides a slick appearance to the top surface of the fully cured unit.

SPECIAL FEATURES

This system will stretch under thermal or mechanical stress so that repeated thermal shocks (from +125° C to -40° C) do no harm to either the electrical functionality or the mechanical integrity of properly potted products.

PROCESS TECHNIQUES

The mix ratio is 1:1 by volume which makes automatic metering, mixing and dispensing equipment ideally suited for processing this system. This system allows a maximum deviation of 5% from the recommended mix ratio before it will begin to degrade into a lesser product.

A typical production facility should include a method for charging sand and vibrating it so that an even distribution is achieved among the solid state components. The sand-filled unit should then be heated to some temperature above 100° C in order to vaporize absorbed moisture and provide a heat source for warming the epoxy system. The epoxy system should be introduced into the unit while the unit itself is at some temperature above that of the curing oven. This technique prevents air bubbles from being trapped in the epoxy system as it gels.

This system will cure at 25° C, but more practical temperatures between 80° C and 95° C will allow a full cure to take place in one hour. Never cure volumes of even 100 grams above 100° C, since gelation at too high a state of molecular activity can force the system to separate from the housing during cooling or, to fail during changes in temperature under service conditions.

PROPERTIES 
  Specific     Part A - 1.1      Color:       Part A: Clear
  Gravity:     Part B - 1.0                   Part B: Clear Orange
                  Mix - 1.1                      Mix: Clear Orange

Mix Ratio, A:B by weight:  100:86    Viscosity   Part A: 6000 cps
           A:B by volume:  1:1        @ 25° C:    Part B:  500 cps
           A:B by volume:  1:1                      Mix: 1700 cps

 Gel Time
     10 gram @ 25° C:         >1 day      Viscosity   Part A -  ---
     10 gram @ 85° C:          1 hour        @ 85° C:  Part B -  ---
     10 gram @ 100° C:        20 minutes                 Mix -  70 cps

  Cure Schedule:             1-1/2 to 2 hours @ 85° C
PROPERTIES OF CURED MATERIAL 
    Hardness, Shore A, ASTM D 2240, (15 second dwell):        70 + 10

    Tensile Strength, psi, ASTM D 638, @ 25° C:                550

    Tensile Elongation, Percent, ASTM D 638, @ 25° C:          93

    Tensile Strength, psi, ASTM D 638, @ -22° C:               10,000

    Tensile Elongation, Percent, ASTM D 638, @ -22° C:         9

    Chemical Absorption (weight gain), Percent, ASTM D 570
       Water (24 hours):                                      0.27
       Water (10 days):                                       0.82
       Gasoline (10 days):                                    8.25
       Salt Water (10 days):                                  0.67
       Motor Oil (10 days):                                   0.05

    Volume Resistivity, ohm-cm, ASTM D 257, @ 25° C
          (500 volts for 1 minute):                       1.6 x 1014

    Dielectric Strength, volts/mil, ASTM D 149
       Short Time Test, @ 25° C:                               350

    Dissipation Factor, @ 1 MHz, ASTM D 150, @ 25° C:          0.02

    Dielectric Constant, @ 1 MHz, ASTM D 150, 25° C:           4.11



            DANGER                            FIRST-AID
--------------------------------     -------------------------
May cause severe irritation.         Eyes - Immediately flush
Do not get in eyes, on skin          eyes with plenty of water
or clothing.                         for at least 15 minutes.
Do not inhale vapors.                Get medical attention.
Wear rubber gloves & aprons.         Skin - Wash immediately
Use with adequate ventilation.       with soap and water.
Wash thoroughly after handling.      Clothing - Remove clothing
For industrial use only.             and wash before reuse.
Keep container closed.
Do not reuse this container.
Spec Sheet Dated: 07/31/84

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Updated: September 26, 1996