Synthetic Rubber 1B58LU

HumiSeal® 1B58LU conformal coating is:

  • fast drying
  •  single component
  •  synthetic rubber based
  • used with Thinner 903 or 905

HumiSeal 1B58 conformal coating has:

  • extremely low moisture vapor permeability
  • improved thermal stability
  • excellent flexibility, low stress on components
  • fluoresces under UV light for ease of inspection and is easily repaired
  • methylcyclohexane which is more environmentally friendly than traditional solvents
  • full compliance with the RoHS directive 2015/863/EU
  • IPC-CC-830 compliant

Application of HumiSeal® 1B58LU

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.

The application of conformal coatings over no clean flux is a common practice. The user should perform adequate testing to confirm compatibility between the conformal coating and their particular assembly materials and process conditions. Please contact HumiSeal for additional information.

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 (5-15 cm/min) will further ensure 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 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.


HumiSeal® 1B58LU can be sprayed using conventional spraying equipment. Spraying should be done in an environment with adequate ventilation so that the vapor and mist are carried away from the operator. The addition of HumiSeal® Thinner 903 or 905 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 used and operator technique. The recommended ratio of HumiSeal® 1B58LU to HumiSeal® Thinner 903 or 905 is 1:1 by volume, however, the ratio may need to be adjusted to obtain a uniform coating.

HumiSeal® 1B58LU may be brushed with a small addition of HumiSeal® Thinner 903 or 905. Uniformity of the film depends on component density and the operator’s technique.

HumiSeal® 1B58LU should be stored away from excessive heat or cold, in tightly closed containers. HumiSeal® products may be stored at temperatures of 0 to 35°C. Prior to use, allow the product to equilibrate for 24 hours at a room temperature of 18 to 32°C

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

The solvents in HumiSeal® Conformal Coatings are flammable. The material should not be used in presence of open flame or sparks. Use only in well-ventilated areas to avoid inhalation of vapors or spray. Avoid contact with skin and eyes.

Consult MSDS/SDS prior to use.

Product Specification
Density, per ASTM D1475 0.77 ± 0.02 g/cm3
Solids Content, % by weight per Fed-Std-141, Meth. 4044 20 ± 1.5 %
Viscosity, per Fed-Std-141, Meth. 4287 240 ± 130 centipoise
VOC 628 grams/liter
Drying Time to Handle per Fed-Std-141, Meth. 4061 10 minutes
Recommended Coating Thickness 25 – 75 microns
Recommended Curing Conditions 24 hrs @ RT or 30 min @ 76°C
Time Required to Reach Optimum Properties 7 days
Recommended Thinner HumiSeal Thinner 903, 905
Recommended Stripper Stripper 1080
Shelf Life at Room Temperature, DOM 18 months
Thermal Shock, 50 cycles per MIL-I-46058C -65°C to 125°C
Glass Transition Temperature – DSC -49.6°C
Tensile Strength, treated at 140°C 33.6 MPa, 27.0 MPa (after 1,000 hours),
18.6 MPa (after 2,000 hours), 11.6 MPa (after 3,000 hours)
Extension, treated at 140°C 503 %, 484 % (after 1,000 hours),
443 % (after 2,000 hours), 96 % (after 3,000 hours)
Moisture Vapor Transmission, per ASTM E398-03 5.2 g/m2 • day • mil
Dielectric Withstand Voltage, per MIL-I-46058C >1500 volts
Insulation Resistance, per MIL-I-46058C 5.0 x 1014 ohms (500TΩ)
Moisture Insulation Resistance, per MIL-I-46058C 7.5 x 1013 ohms (75GΩ)

Other products in this chemistry include:

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