Dowsil – How to bond and dissipate heat from electronic devices ?

How to improve the thermal dissipation of your electronic assemblies ?

Dow, with its product range Dowsil™, has developed thermally conductive adhesives with the same advantages as standard adhesives with the added feature of thermal conductivity.

These Dowsil™ adhesives are used where a permanent bond is desired, where mechanical fixation is not possible or undesirable, where thermal movement is required to articulate the bond, and where maintenance or rework is unlikely to be required.

Thermally conductive adhesives are ideally suited for bonding power components, heat sinks and other applications where flexibility and thermal conductivity are major concerns.

Heat-curing fluid versions are also suitable for transformers, power supplies, coils and other electronic devices where improved thermal conductivity is required.

Silicones generate very little stress on components even when containing thermally conductive fillers.

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Why are Thermal Interface Materials (TIMs) necessary? Or how to reduce thermal resistance?

Even when the surfaces of two components are in direct contact, the difference in surface finish (roughness) creates voids (gaps). Air trapped in these voids will then limit heat transfer.

TIMs will therefore help to close the gap between two components and promote heat transfer by reducing thermal resistance.

Silicones Dowsil™ curing at room temperature RTV

References	Properties	Thermal conductivity (W/m.K)	Viscosity (mPa.s)	Shore	Tensile strength (MPa)	Elongation (%)	Temperature Range	Rigidité diélectrique (kV/mm)	Conditionnements
Dowsil™ SE 4485	Blanc – UL 94 V0	2.8	NA	A90	3.4	20	-40°C / +120°C	19	330 ml Cartridge
Dowsil™ TC 1500	Blanc	1.55	NA	A82	2.7	NC	-45°C / +200°C	18	330 ml Cartridge
Dowsil™ SE 4420	Blanc	0.92	108 000	A76	4.1	77	-45°C / +200°C	14.6	330 ml Cartridge

HTV hot-curing silicones Dowsil™

Dowsil™ silicones are available in fluid versions for hot curing where improved thermal conductivity is required.

References	Properties	Thermal conductivity (W/m.K)	Viscosity (mPa.s)	Shore	Tensile strength (MPa)	Elongation (%)	Temperature Range	Dielectric strength (kV/mm)	Packaging
Dowsil™ TC 2035	Red – Two part	3.3	125 000	A95	3.6	43	-40°C / +200°C	21	Kit 2 kg – 3.2 kg
Dowsil™ SE 4450	Grey – One part	1.92	66 000	A95	6.7	46	-45°C / +200°C	21	1 kg Can
Dowsil™ 1-4173	Grey – One part	1.8	61 000	A92	6.2	20	-45°C / +200°C	16.7	Cartridge 75 ml 1.5 kg Cartridge

Permabond epoxy and acrylic adhesives

The excellent chemical resistance of epoxy resins makes them suitable for severe environmental conditions. Permabond acrylic adhesives have a very fast setting time, allowing for a high yield.

References	Properties	Thermal conductivity (W/m.K)	Viscosity (mPa.s)	Shore	Tensile strength (MPa)	Elongation (%)	Temperature Range	Dielectric strength (kV/mm)	Packaging
Permabond MT3826	Yellow – Two part composant – hybrid epoxy – Handling time : 2-3h	1.4 – 1.6	350 000	A55	1-2	>80	-40°C / +150°C	18-20	400 ml Cartridge
Permabond TA4392	Acrylic – White – One part – Handling time : 2-3 min	1.11	200 000 – 400 000	D65	15-20	1.5	-55°C / +100°C	25-30	300 ml Cartridge