Application of a water-based 1122

Conformal coatings can be successfully applied to substrates that have been cleaned prior to coating and also to substrates assembled with low residue “no clean” materials.  Users should perform adequate testing to confirm compatibility between the conformal coating and their particular assembly materials, process conditions and cleanliness level.  Please contact HumiSeal^® for additional information.

Waterborne coatings should not be placed directly on bare/untreated steel. Applying waterborne coatings when the Relative Humidity is > 80% will adversely affect coating uniformity and can cause poor adhesion.

Dipping
Depending on the complexity, density and configuration of components on the assembly, it may be necessary to reduce the viscosity of HumiSeal® 1122 with deionized water in order to obtain a uniform film. Once optimum viscosity is determined, a controlled rate of immersion (30 cm/min) and withdrawal (10 cm/min) will ensure uniform deposition of the coating. During the application, evaporation will cause an increase in viscosity. Viscosity in the dip tank should be checked regularly, using simple measuring devices such as a Zahn or Ford viscosity cup. The viscosity should be adjusted by adding small amounts of deionized water. Various conditions, such as ambient humidity and temperature, will affect the viscosity and drying times of the coating. Conditions in the manufacturing environment should be kept as stable as possible.

Spraying
HumiSeal® 1122 can be sprayed using conventional spraying equipment. The addition of deionized water is necessary to ensure a uniform spray pattern resulting in pinhole-free film. The amount of deionized water and spray pressure will depend on the specific type of spray equipment being used. It is recommended that the operator adjust the viscosity, beginning with addition of deionized water at approximately 3% to 5% by volume. It is not uncommon to use atomizing pressures as high as 90 psi to obtain a uniform film. Do not flood the board. Optimum coverage is achieved by spraying in four layers, rotating the board 90o between each complete pass. Excessive thinning of HumiSeal® 1122 should be avoided. It will negatively impact coating quality and performance.

Brushing
HumiSeal® 1122 may be brushed after thinning with deionized water. The uniformity of the finished coating will depend on component density, coating viscosity, and the operator’s technique.

Curing
After application, allow the coating to dry to a tack-free state. This should take approximately 20 min @ 25°C. Once the coating has reached a tack-free state, an oven curing cycle is recommended. Actual time to cure will be affected by various conditions such as coating thickness, ambient humidity, and ambient temperature.

Storage
HumiSeal® 1122 should be stored at room temperature in tightly closed containers. The coating contains water and care should be taken to prevent it from freezing. Containers of frozen HumiSeal® 1122 must be brought back to room temperature, stabilized overnight and thoroughly stirred prior to use.

Caution
Application of HumiSeal® Conformal Coatings should be carried out in accordance with local and National Health and Safety regulations.