Silver Conductive Coating

Created by Nicole Smith, Modified on Tue, 7 May at 4:55 PM by Kathleen Patrick

EMS12684-15 – Silver conductive 18DB70X coating (DG)

EMS Silver Conductive Coating is a highly conductive acrylic paint designed to take conductive paths or reduce electromagnetic or radio frequency interference (EMI/RFI). Because it is a durable acrylic resin, long-term protection from EMI/RFI is assured. It minimises loss of metallisation through rubbing, and by the oxidation resistant silver that slows down conductivity degradation with age. The flake shape helps ensure maximum points of contact to ensure better conductivity. Loss of shielding through paint peeling is unlikely since the acrylic resin system has been UL-tested and shown to adhere to even difficult substrates like AMS and polycarbonates.

The primary application is to provide an excellent conductivity EMI/RFI shielding suitable for harsh environments. It may also act as a conductive base for applications where it is necessary to impart the highest degree of conductivity to a surface. Being non-magnetic, it also offers a low relative permeability that provides reasonable skin depths, which makes it ideal for microwave transmissions applications.

Feature Highlights and Benefits

Environmentally meets RoHS directive for Low-VOC
Stronger adhesion than water-based coatings

Rub-off resistant
Repairable and removable thermoplastic paint system
Tough and durable coat with excellent weatherability
Corrosion resistant coating: Salt-Spray Tested
Meets MIL-STD-883H (Volume Resistivity = 0.0002Ω·cm)

High Surface Conductivity (≥15 Siemen)–Low Surface resistance of 0.066Ω /sq @ 1 mil
Median attenuation 75 dB ±20 dB per 25.4 µm (~1.0 mil) for frequency range of 10 MHz to 18 GHz

Cure Rates and Shelf Life

*Dry to Touch (Liquid):	3 to 5 min
*Recoat time (Liquid):	2 min
Full Cure at room temp.:	24 hour
Full Cure at 65°C:	1 year
**Storage Temperature Limits:	-5 to +40°C

*Assumes let 1.00:0.75 let down with thinner.
**The product must stay within storage temperature limits stated.

Service Ranges

Service Temperature:	-40 to +120°C
***Maximum coverage per 900ml:	<168 000 cm²
***Maximum coverage per US gal:	<709 000 cm²

***Idealised estimate based on a coat thickness of 25 µm (1.0mil) and 65% transfer efficiency.

Principal Components and their CAS Number

Silver:	7440-22-4
Acrylic Resin:	9003-01-4
Acetone:	67-64-1
Ethanol:	64-17-5
Toluene:	108-88-3

Properties of Cured EMS Conductive Silver Coating

NOTE: The first coat thickness is typically around 25 µm [1.0 mil].

Electric & Magnetic Properties	Method	Value
Volume Resistivity (Tested by an external and independent laboratory using four point probe.)	Method 5011.5 in MIL-STD-883H	0.0002 Ω·cm
Surface Resistance :1 x coat @ 1 mil	square probe	Resistance Conductance 0.066 Ω/sq 15S
:2 x coats @ 2 mil	"	0.055 Ω/sq 18S
:3 x coats @ 2.5 mil	"	0.040 Ω/sq 25S *NOTE: Surface resistance is given in /sq and the corresponding conductance in Siemens (S or )
Magnetic class relative permeability		Diamagnetic (Non-magnetic) <1.0
Shielding Attenuation 33 µm [1.0 mil]
10 to 100 kHz	IEEE STD 299-1997	54 dV to 75 dB
100 kHz to 1 MHz	"	50 dB to 65 dB
1 MHz to 10 MHz	"	54 dB to 65 dB
10 MHz to 100 MHz	"	41 dB to 54 dB
100 MHz to 1 GHz	"	35 dB to 67 dB
1 GHz to 10 GHz	"	41 dB to 59 dB
10 GHz to 18 GHz	"	36 dB to 72 dB
Physical Properties	Method	Value
Resin technology	–	Lacquer (Thermoplastic)
Colour	Visual	Metallic Silver Grey
Abrasion resistant	–	Yes
Blister resistant	–	Yes
Peeling resistant	–	Yes
Environmental & Aging Study	Method	Value
Salt Spray Test: 7 day @35 °C +Salt/Fog	ASTM B117-2011
Cross-hatch adhesion	ASTM D3359-2009	5B = 0% area removed
Cracking, unwashed area	ASTM D661-93	None
Visual Colour, unwashed area	ASTM D1729-96	Severe yellowing & discoloration
Peeling, unwashed area	ASTM D1729-96	None

Graph–Silver Coating Surface Resistance at Different Thicknesses

Properties of Uncured EMS Conductive Silver Coating

Physical Property: Mixture Colour: Metallic silver grey

Density @ 25°C2.15 g/mL

Solids Percentage (wt/wt) (Percentage for liquid only before thinning)~73%

Viscosity at 25°C (Brookfield viscometer)~8,000 cP

Flash Point-16°C

Odour Ethereal, benzene-like

Compatibility

Chemical

The silver filler is very resistant to oxidation, except in environments containing contaminants such as ozone or H2S, which tarnish its surface. Silver oxide remains conductive so degradation due to oxidation is not as bad as it is with many other metal oxides.
Common paint solvents like acetone, toluene, MEK, and xylene can dissolve the thermoplastic resin. This does make for easier coating repair and work characteristics but is also makes the coating unsuitable for environments that have a lot of solvents.

Adhesion

EMS Conductive Silver Paint coating adheres to acrylics, metals, epoxies, wood, ABS, PBT, PC, PU, and PVA. NOTE: It is not compatible with contaminants like water, oil, and greasy flux residues which may affect adhesion. If contamination is present, clean the surface before coating.

Storage

Store in a dry area, between -5°C and 40°C (23°C and 104°F).