HumiSeal 1A27

Product Specification

Density, per ASTM D1475

0.96 ± 0.02 g/cm³

Solids Content, % by weight per Fed-Std-141, Meth. 4044

50 ± 3 %

Viscosity, per Fed-Std-141, Meth. 4287

3000 ± 1000 centipoise

VOC

480 grams/litre

Recommended Coating Thickness

25 – 75

Drying Time to Handle per Fed-Std-141, Meth. 4061

30 minutes

Optional Curing Conditions to Reach Optimum Properties

30 days at RT

30 hours @ 76°C

20 hours @ 88°C

Recommended Thinner (spraying)

HumiSeal Thinner 521

Recommended Stripper

HumiSeal Stripper 1063

Shelf Life at Room Temperature, DOM

24 months

Thermal Shock, 50 cycles per MIL-I-46058C

-65° to 125°C

Coefficient of Thermal Expansion – TMA

170 ppm/°C

Glass Transition Temperature – DSC

28°C

Modulus – DMA

18.1 MPa

Flammability, per UL 94

V-0

Dielectric Withstand Voltage, per MIL-I-46058C

>1500 volts

Dielectric Breakdown Voltage, per ASTM D149

7500 volts

Dielectric Constant, at 1MHz and 25°C per ASTM D150-98

3.6

Dissipation Factor, at 1MHz and 25°C per ASTM D150-98

0.02

Insulation Resistance, per MIL-I-46058C

2.0 x 10¹⁴ ohms(200TΩ)

Moisture Insulation Resistance, per MIL-I-46058C

1.2 x 10¹⁰ohms (12GΩ)

HumiSeal 1A27 offers the following features:

Urethane chemistry

chemically resistant

single component

contains no free isocyanates

used in combination with Thinner 521

RoHS directive 2015/863/EU

recognized under UL File Number E105698

excellent moisture and environmental protection for printed circuit assemblies

RoHS Directive 2002/95/EC compliance

Application of 1A27 Conformal Coating

Successful application of conformal coatings requires clean substrates, whether they have been cleaned before coating or assembled with low residue “no clean” materials. It is important to perform proper testing to confirm the compatibility of the conformal coating with the specific assembly materials, process conditions, and cleanliness levels. For further details, please contact a HumiSeal representative.

Dipping

To achieve a uniform film on assemblies with complex, dense, or uniquely configured components, it may be necessary to reduce the viscosity of HumiSeal 1A27 using HumiSeal Thinner 521. Once the optimal viscosity is reached, a controlled rate of immersion and withdrawal (typically 5 to 15 cm/min) will ensure an even coating application. As solvent evaporates during application, the viscosity will increase and should be adjusted with small amounts of HumiSeal Thinner 521. Regular checks of the viscosity using a Zahn or Ford viscosity cup are recommended.

Spraying

HumiSeal 1A27 can be sprayed with conventional spraying equipment. To ensure proper ventilation and remove vapor and mist the operator, spraying should take place in a well-ventilated area. The addition of HumiSeal Thinner 521 is needed to maintain a uniform spray pattern that results in a pinhole-free coating. The amount of thinner and spray pressure required will depend on the spray equipment used and operator technique. A 1:1 volume ratio of HumiSeal 1A27 to HumiSeal Thinner 521 is recommended, though adjustments may be needed for optimal coating quality.