Humiseal 1A33 Polyurethane Conformal Coating

HumiSeal 1A33 contains no free isocyanates and fluoresces under UV light for inspection purposes. HumiSeal 1A33 coating is MIL-I-46058C qualified, IPC-CC-830B and RoHS Directive 2011/65/EC compliant and recognized under UL File Number E105698.

• Urethane chemistry
• chemically resistant
• single component
• contains no free isocyanates
• used in combination with Thinner 503/521
• MIL-I-46058C qualified
• RoHS directive 2015/863/EU
• Recognized under UL File Number E105698
• excellent moisture and environmental protection for printed circuit assemblies
• fluorescence under UV light for ease of inspection

Application of 1A33 Conformal Coating

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 a HumiSeal representative for additional information.

Dipping

Depending on the complexity, density and configuration of components on the assembly, it may be necessary to reduce the viscosity of HumiSeal 1A33 with HumiSeal Thinner 503 in order to obtain a uniform film. Once optimum viscosity is determined, a controlled rate of immersion and withdrawal (typically, 5 to 15 cm/min) will further ensure even deposition of the coating and provide a uniform film. During application, evaporation of solvent causes an increase in viscosity that should be adjusted by adding small amounts of HumiSeal Thinner 503. Viscosity in the dip tank should be checked regularly using a simple measuring device, such as a Zahn or Ford viscosity cup. 

Spraying

HumiSeal 1A33 can be sprayed using conventional spraying equipment. Spraying should be done in an environment with adequate ventilation so that vapor and mist are carried away from the operator. The addition of HumiSeal Thinner 521 is necessary to ensure a uniform spray pattern resulting in a pinhole-free film. The amount of thinner and spray pressure will depend on the specific type of spray equipment and operator technique. The recommended ratio of HumiSeal 1A33 to HumiSeal Thinner 521 is 1:1 by volume; however, the ratio may need to be adjusted to obtain a uniform coating.

Brushing

HumiSeal 1A33 may be brushed with a small addition of HumiSeal Thinner 503. Uniformity of the film depends on the component density and operator technique.