Epoxy Resin For Potting Of Electronic Components

In electronics, potting is a process of filling a complete electronic assembly with a solid or gelatinous compound for high voltage assemblies by excluding gaseous phenomena such as corona discharge, for resistance to shock and vibration, and for the exclusion of water, moisture, or corrosive agents. Thermosetting plastics or silicone rubber gels are often used, though epoxy resins are also very common. Many sites recommend using a potting product to protect sensitive electronic components from impact, vibration, and loose wires.

In the potting process, an electronic assembly is placed inside a mold which is then filled with an insulating liquid compound that hardens, permanently protecting the assembly. The mold may be part of the finished article and may provide shielding or heat dissipating functions in addition to acting as a mold. When the mold is removed the potted assembly is described as cast.

an alternative, many circuit board assembly houses coat assemblies with a layer of transparent conformal coating rather than potting.[5] Conformal coating gives most of the benefits of potting, and is lighter and easier to inspect, test, and repair. Conformal coatings can be applied as liquid or condensed from a vapor phase.

TECHNICAL SPECIFICATION

Burhani Resin EP- 60F and Hardener EH – 408

General Information:-

EP – 60F is a DGEBA type of Epoxy resin, suitably formulated and processed to obtain void free encapsulation and castings.

Hardener EH –408 is a Polyamide hardener.

Generally, it is used for adhesive, castings, encapsulation & potting of electronic components.

Properties of the resin EP - 60F :

Property.	Method.	Unit.	Specification.
Appearance.	Visual	------	Opaque, viscous liquid. ( Green/Black)
Viscosity at 30° C By Din cup 10.	RPC/STP/009. Dt.10/05/2018.	Sec	30 - 40
Ash Content.	RPC/STP/010. Dt.10/05/2018.	%	49 -51
Specific gravity at 25° C.	RPC/STP/009. Dt.10/05/2018.	------	1.50 – 1.60
Flash Point		° C	>100
Storage stability	when stored in original Containers atR.T	Months	12

Properties of the hardener EH – 408:-

Property	Method	Unit.	Specification.
Type of compound	-----	------	Polyamide
Appearance	Visual	------	Amber coloured viscous liquid
Viscosity at 25° C By Brookfield	RPC/STP/007. Dt.10/05/2018.	cps	200 - 600
Amine Value	RPC/STP/002. Dt.10/05/2018.	eq/kg	348 - 404
Specific gravity at 25° C	RPC/STP/009. Dt.10/05/2018.	------	0.94 – 0.96

0.94 – 0.96	when stored in original Containers atR.T	Months	12

Mix ratio and Pot life:

Property	Method	Unit.	Observed Value.
Initial Mix Viscosity @ around 30°C. EP – 60F : EH – 408 100:25	RPC/STP/007. Dt.10/05/2018	cps	1600
Pot life at R.T	RPC/STP/008. Dt.10/05/2018	Minutes	120 - 160
Curing in thick layer.	Mix ratio 100:25	----	Tack free & Hard mass.

Schedule:

Curing Temperature °C 20 30 40

Curing Time 48hrs 24hrs 16-20 hrs

Post Curing: 4 - 6 Hrs at 80°C if necessary.

Typical properties of cured compound:

Specimen Cured at 16 hours at RT and 4 hours at 80°C.

S.No	Property	Method	Unit	Observed value
1	Flexural Strength	ISO -178	MPa.	36.5
2	Izod impact strength (un notched)	ISO – 179	Kj/m²	10.36
3	Compressive strength	ISO - 604	MPa	69
4	Tensile strength Test speed: 5mm/min	ISO - 527	MPa	27.5
5	Hardness	ISO - 868	Shore D	79
6	Heat Distortion Temperature.(Martens)		°C	Under Study
7	Co-efficient of linear thermal expansion (CLTE) 30 - 60°C	ASTM D - 696	/ °C	4.20 x 10¯ 5
8	Thermal conductivity @55°Cmean temperature	ASTM E - 1530	W/mk	0.401
9	Di electric strength @RT	ASTM D - 149	kV/mm	14.2
10	Volume resistivity @ DC 500 V for l minute	ASTM D - 257	Ohms - cm	1.3 x 10¹
11	Dielectric constant @ 1 KHz RT	ASTM D - 150	-----	2.92
12	Dissipation factor @ 1 KHz RT	ASTM D - 150	-----	0.0290099
13	Comparative tracking index @ RT	ASTM D - 3638	v	Greater than 600

Chemical Resistance :

S.No	Chemical	Method	Unit.	Observed value.
1	25% H2 SO4 @RT (24hours) a) Weight change b) Dimensional change c) Visual appearance	ISO – 175	%	+ 0.55 Nil No discoloration , no delamination and deformation is observed.
2	5% NaOH @RT (24hours) a) Weight change b) Dimensional change c) Visual appearance	ISO – 175	%	+ 0.24 Nil No discoloration , no delamination and deformation is observed.

Chemical Resistance :

S.No	Chemical	Method	Unit.	Observed value.
1	25% H2 SO4 @RT (24hours) a) Weight change b) Dimensional change c) Visual appearance	ISO – 175	%	+ 0.55 Nil No discoloration , no delamination and deformation is observed.
2	5% NaOH @RT (24hours) a) Weight change b) Dimensional change c) Visual appearance	ISO – 175	%	+ 0.24 Nil No discoloration , no delamination and deformation is observed.

SAFETY PRECAUTIONS: Avoid direct contact of resin/ hardener with skin. Use of hand gloves during handling is recommended. Splashes on the skin, if any should be removed immediately with suitable remover.

Note:- The information given here reflects our present experience in development and usage. Since site conditions and situations vary, no warranty is given or responsibility assumed for obtaining specific technical results.