ETC 1B31

Acrylic Coating
System Description
A fast air drying, single component, acrylic coating that provides excellent moisture and environmental protection for
printed circuit assemblies. The final film demonstrates excellent flexibility and is easily repairable. This coating is MILI-46058C and IPC-CC-830 qualified. Fluoresces under UV light for ease of inspection.
Properties of Liquid HumiSeal
Specific weight, (lb. per gal.) per ASTM, Meth. D1475
Solids Content, % by weight per Fed-Std-141, Meth.4044
Viscosity, centipoise per Fed-Std--141, Meth. 4287
Flashpoint, 0C (0F) per ASTM, Meth. D56
VOC (grams / liter)
Drying Time to Handle per Fed-Std-141, Meth.4061
Recommended Coating Thickness
Recommended Curing Conditions
Time Required to Reach Optimum Properties
Thinner, if needed (dipping & brushing)
Recommended Stripper
Pot Life at Room Temperature
Shelf Life at Room Temperature
7.6 ± .2
35 ± 3
197 ± 15
-1 (30)
10 minutes
1 - 3 mils
24 hrs @ rm. temp or 30 min.@ 1700F
7 days
Thinner 503
Thinner 521
Stripper 1080
12 months
12 months
Properties of Cured HumiSeal
Thermal Properties
Continuous Use Operating Range 0C(0F)
Thermal Shock, per MIL-I-46058C
Coefficient of Thermal Expansion - DMA
Glass Transition Temperature - TMA
Young’s Modulus - DMA
Physical Properties
Build per Dip, mils, per ASTM, Meth.D823
Flexibility, per MIL-I-46058C
Adhesion, per ASTM, Meth. D2197
Flammability, per ASTM, Meth. D635
Weather Resistance
Electrical Properties
Dielectric Withstand Voltage, volts per MIL-I-46058C
Dielectric Breakdown Voltage, volts, per ASTM, Meth. D149
Dielectric Constant, at 1MHz and 250C, per ASTM-D150-65T
Dissipation Factor, at 1MHz and 250C, per ASTM-D150-65T
Insulation Resistance, ohms, per MIL-I-46058C
Moisture Resistance, ohms, per MIL-I-46058C
Chemical Properties
Main Constituent
Fungus Resistance, per ASTM-G21
Resistance to Chemicals
-650C (-850F) to +1250C (2570F)
55ppm / 0C
1000 psi
Very Good
800 x 1012 (800T)
60 x 109 (60G)
Values are not intended for use in preparation of specifications.
Revised 06-18-04
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Acrylic Coating
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 and all other contaminants. Contamination under the coating
will cause problems that may lead to assembly failures.
HumiSeal coatings may be applied by brush, dip or spray.
Depending on the complexity, density and configuration of components on the assembly, it may be necessary to
reduce the viscosity of HumiSeal 1B31™ with HumiSeal Thinner 503 in order to obtain a uniform film. Once
optimum viscosity is determined, a controlled rate of immersion and withdrawal (2 to 6" per minute) will further insure
even deposition of the coating and ultimately a uniform film. During the application, evaporation of solvent causes
an increase in viscosity that should be adjusted by adding small amounts of Thinner 503. Viscosity in the dip tank
should be regularly checked by the use of a simple measuring device such as a Zahn or Ford viscosity cup.
HumiSeal 1B31™ can be sprayed using conventional spraying equipment. As a rule, the addition of Thinner 521 is
necessary to assure a uniform spray pattern resulting in pinhole free film. The amount of thinner and spray pressure
will depend on the specific type of spray equipment used. The spraying should be done under an exhaust hood so
that the vapor and mist are carried away from the operator. The recommended ratio of HumiSeal 1B31™ to
HumiSeal Thinner 521 is 1 to 1 by volume, as a starting point. The quantities may be adjusted to obtain a uniform
HumiSeal 1B31™ may be brushed with a small addition of HumiSeal Thinner 503. Uniformity of the film depends on
component density and operator's technique.
HumiSeal 1B31™ should be stored at room temperature, away from excessive heat, in tightly closed containers.
HumiSeal products may be stored at temperatures of 0-100°F. Avoid direct sunlight. Prior to use, allow the product
to equilibrate for 24 hours at 65-90°F.
The solvents in HumiSeal 1B31™ are flammable. Do not use in presence of open flame or sparks. Avoid inhalation
of vapors or spray. Use only in well-ventilated areas. Avoid contact with skin and eyes. If contact occurs, wash with
soap and water. If swallowed, call physician immediately. Refer to MSDS before use.
All technical data in this bulletin is based on test results and is believed to be correct. However, since the end use of HumiSeal materials (and the manner
of storing and handling them) is beyond our control, we make no warranty-expressed or implied as to the fitness of use, results to be obtained from or effects
of use with respect to these materials. Their use shall be solely by the judgment of and at the risk of the user notwithstanding any statement in this
bulletin. © Copyright 1992 CHASE CORPORATION. HumiSeal and 1B31™ are trademarks of Chase Corporation.
HumiSeal Division Chase Corporation
Woodside, NY 11377-0445/Tel: (718) 932-0800/Fax: (718) 932-4345
[email protected]
Revised 06-18-04
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