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HumiSeal 1C55 Silicone Conformal Coating

HumiSeal® 1C55 is a single component, VOC-free, low viscosity, fast thermal curing silicone conformal coating. The low viscosity and long pot life of HumiSeal® 1C55 make it ideal for dipping and spraying. HumiSeal® 1C55 demonstrates excellent flexibility, contains an optical brightener for inspection under black light and is repairable. HumiSeal® 1C55 coating is RoHS Directive 2002/95/EC compliant.
Manufacturer: Humiseal

Properties of HumiSeal® 1C55

Density, per ASTM D1475 0.98 ± 0.02 g/cm³
Min. Solids Content, % by weight per Fed-Std-141, Meth. 4044 99 %
Viscosity, per Fed-Std-141, Meth. 4287 245 ± 55 centipoise VOC 0 grams/litre Recommended Coating Thickness 50 - 200 microns
Recommended Curing Conditions 10 - 15 minutes @ 105 - 130ºC Time Required to Reach Optimum Properties 15 minutes
Recommended Stripper HumiSeal® Stripper 1090
Shelf Life at Recommended Conditions, DOM 12 months Thermal Shock, 50 cycles per MIL-I-46058C -65°C to 200°C Glass Transition Temperature - DSC < -65ºC Coefficient of Thermal Expansion - TMA 154 ppm/°C Modulus - DMA 0.7 MPa @ -40ºC
0.6 MPa @ 25ºC
0.5 MPa @ 80ºC Tensile 0.15 MPa Elongation 16%
Dielectric Withstand Voltage, per MIL-I-46058C >1500 volts Dielectric Breakdown Voltage, per ASTM D149 7000 volts Dielectric Constant, at 1MHz and 25°C per ASTM D150-98 2.4
Dissipation Factor, at 1MHz and 25°C per ASTM D150-98 0.01
Insulation Resistance, per MIL-I-46058C 5.0 x 1014 ohms (500TΩ) Moisture Insulation Resistance, per MIL-I-46058C 1.0 x 1010 ohms (10GΩ) Fungus Resistance, per ASTM G21 Passes

Application of HumiSeal® 1C55

Cleanliness of the substrate is of extreme importance for the successful application of a conformal coating. Surfaces must be free of moisture, dirt, wax, grease, flux residues and all other contaminants. Contamination under the coating could cause problems which may lead to assembly failures.


A controlled rate of immersion and withdrawal (5-15 cm/min) will ensure even deposition of the coating and ultimately a uniform film.


HumiSeal® 1C55 may be brushed. Uniformity of the film depends on component density and operator's technique.


HumiSeal® 1C55 can be sprayed using conventional spraying equipment. Spray pressure will depend on the specific type of spraying equipment used and operator technique. Spraying should be done in an environment with adequate ventilation so that the vapour and mist are carried away from the operator. The use of thinner is not required or recommended for HumiSeal® 1C55.


HumiSeal® 1C55 is a thermally cured conformal coating. The actual curing temperature of HumiSeal® 1C55 is dependent upon several parameters such as heat sink characteristics of parts being coated, the type of oven used for curing process, as well as oven loading parameters.
The cure mechanism for HumiSeal® 1C55 may be inhibited by a variety of materials such as amines, acrylates, certain ingredients from latex rubber, etc. It is recommended that process and material compatibility be considered when incorporating HumiSeal® 1C55 into the production environment. Cotton gloves are recommended for operators who will be handling assemblies prior to coating with HumiSeal® 1C55.


HumiSeal® 1C55 should be stored at 27°C or below in tightly closed containers away from direct sunlight. Refrigerated storage of HumiSeal® 1C55 will extend its shelf life. Prior to use, allow the product to equilibrate for
24 hours at room temperature.


Application of HumiSeal® Conformal Coatings should be carried out in accordance with local and National Health and Safety regulations.
Use only in well-ventilated areas to avoid inhalation of vapours or spray. Avoid contact with skin and eyes. Consult MSDS/SDS prior to use.



Conro Electronics Ltd
Unit 7, Orbital 25, Dwight Road, Watford, Hertfordshire
WD18 9DA

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