HumiSeal® UV550 is a solvent-free, UV-curable elastomeric acrylate conformal coating with higher flexibility than other UV-curable conformal coatings. HumiSeal® UV550 has been designed to withstand at least 1000 cycles of thermal shock between adjacent components in areas of high thickness. The SIR characteristics are stable for over 1000 hours. The material can be cured by LED or Arc or Microwave systems.
Key features of HumiSeal® UV550
- Excellent flexibility
- Excellent moisture resistance
- High electrical insulation properties
- Good chemical resistance
- Withstands at least 1000 cycles of thermal shock between adjacent components on populated boards in areas of high thickness.
- Fluorescence under UV light to allow coating
- A secondary cure mechanism that will fully cure any unexposed areas of the coating within 7 days at ambient conditions.
- Exhibits minimal yellowing after high-temperature
- Silicone free
HumiSeal® UV550 meets the following standards:
- Compliant with RoHS Directive EU 2015/863
- Compliant with China RoHS 2
- Compliant to China Standard GB30981-2020
Application of HumiSeal®UV550
Conformal coatings can be successfully applied to substrates cleaned before coating and to substrates assembled with low residue, “no clean” assembly materials.
Spraying
HumiSeal® UV550 can be applied via standard selective coating or conventional hand spray equipment. The source air used for spraying must be dry (a dry air supply or dry inert gas (nitrogen or argon) is highly recommended) to prevent premature curing of the secondary cure mechanism. The spraying should be done with adequate ventilation so the vapor and mist are carried away from the operator.
Curing
HumiSeal® UV550 is a highly crosslinked coating. The product must be exposed to the correct spectral output to achieve maximum crosslinking density. HumiSeal has modeled the performance of UV550 using Arc and microwave-based UV curing equipment, as well as 385 and 395nm LED lamp units.
A higher dose is recommended to minimize surface tack. Due to the presence of oxygen, surface tack is more pronounced when curing by LED. The maximum recommendation represents the highest tested values by HumiSeal. The cure recommendations may change as curing technology develops.
Heat is also an important component of UV cure, and different systems produce different heat outputs. Higher heat levels allow UV cure at lower dose/irradiance levels. Consequently, HumiSeal recommends that curing be discussed with HumiSeal® Technical staff to ensure the exact customer process being used will meet the coating cure requirements.
HumiSeal® UV550 contains a reliable secondary moisture cure mechanism to cure any shadow areas on the assembly within 7 days at ambient moisture.
HumiSeal® UV550 has been designed to be cured using a microwave UV oven equipped with an “H” style bulb or using Arc systems. HumiSeal® UV550 can be cured using 385 and 395nm LED units; however, care must be taken during the equipment selection process to ensure minimum dosage values can be obtained to adequately cure the coating. Because of the variations possible in curing equipment type and configuration, it is strongly recommended that you contact HumiSeal Technical Support to discuss your equipment and process in detail.
Clean Up
Flush equipment and clean uncured HumiSeal® UV550 with non-alcohol-based solvents. HumiSeal® Thinner 521 or Thinner 521EU is recommended.
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