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ABchimie746E UV Soft UV Cure Conformal Coating
- Excellent adhesion
- Fast curing under UV exposure
- Can be soldered through
Product Description
ABchimie 746E UV is a transparent, single‑component conformal coating designed to protect printed circuit boards (PCBs) operating in harsh environmental conditions. It uses dual‑cure technology (UV + humidity), ensuring full polymerization even in shadowed or masked areas where UV light cannot reach. Its low viscosity enables highly controlled, thin‑film application (≈80 µm), making it ideal for modern high‑density electronic assemblies.
ABchimie 746E UV can be applied by brushing, pad printing, spray systems, or selective coating machines, with selective coating being the recommended method for precision and productivity.
Product Key Features
- Excellent adhesion in harsh and variable weather conditions
- UV‑fluorescent for easy inspection of coating coverage
- Wide operating temperature range(–65°C to +150°C)
- Can be soldered through without generating toxic gases
- Certified UL94 V‑0 and UL746E (QMJU2‑E308681)
Applications
- Conformal protection of PCBs in automotive, aerospace, industrial, and outdoor electronics
- High‑density assemblies requiring thin, precise coating layers
Technical Specifications
| General Properties | |
| Appearance Appearance Appearance at room temperature. | Transparent yellow liquid |
| Film Thickness Film Thickness Film thickness is the thickness of a backing film without taking into account any coatings or adhesive layers. It is measured in micron and the conversion factor to mil is 0.039. | 30 - 150 µm |
| Physical Properties | |
| Viscosity Viscosity Viscosity is a measurement of a fluid’s resistance to flow. Viscosity is commonly measured in centiPoise (cP). One cP is defined as the viscosity of water and all other viscosities are derived from this base. MPa is another common unit with a 1:1 conversion to cP. A product like honey would have a much higher viscosity -around 10,000 cPs- compared to water. As a result, honey would flow much slower out of a tipped glass than water would. The viscosity of a material can be decreased with an increase in temperature in order to better suit an application | 0.05 - 0.1 mPa.s |
| Electrical Properties | |
| Breakdown Voltage Breakdown Voltage Breakdown voltage is the minimum voltage necessary to force an insulator to conduct some amount of electricity. It is the point at which a material ceases to be an insulator and becomes a resistor that conducts electricity at some proportion of the total current. After dielectric breakdown, the material may or may not behave as an insulator any more because of the molecular structure alteration. The current flow tend to create a localised puncture that totally alters the dielectric properties of the material. This electrical property is thickness dependent and is the maximum amount of voltage that a dielectric material can withstand before breaking down. The breakdown voltage is calculated by multiplying the dielectric strength of the material times the thickness of the film. | 1750 V |
| Dielectric Strength Dielectric Strength Dielectric strength is measured in kV per mm and is calculated by the Breakdown voltage divided by the thickness of the tested material. Those two properties go hand in hand and while Breakdown voltage is always thickness dependent, dielectric strength is a general material property. As an example, the dielectric strength of Polyimide is 236 kV/mm. If we place 1mm of Polyimide between two electrodes, it will act as an insulator until the voltage between the electrodes reaches 236 kV. At this point it will start acting as a good conductor, causing sparks, potential punctures and current flow. | 60 kV/mm |
| Thermal Properties | |
| Coefficient of Thermal Expansion (CTE), α1 Coefficient of Thermal Expansion (CTE), α1 CTE α1 (alpha 1) is the slope of the Coefficient of thermal expansion in a temperature range below the Glass transition temperature (Tg). It explains how much a material will expand until it reaches Tg. | 200 ppm/°C |
| Coefficient of Thermal Expansion (CTE), α2 Coefficient of Thermal Expansion (CTE), α2 CTE α2 (alpha 2) is the slope of the Coefficient of thermal expansion in a temperature range above the Glass transition temperature (Tg). It explains the extent to which a material will expand after it passes Tg. | 250 ppm/°C |
| Glass Transition Temperature (Tg) Glass Transition Temperature (Tg) The glass transition temperature for organic adhesives is a temperature region where the polymers change from glassy and brittle to soft and rubbery. Increasing the temperature further continues the softening process as the viscosity drops too. Temperatures between the glass transition temperature and below the decomposition point of the adhesive are the best region for bonding. The glass-transition temperature Tg of a material characterizes the range of temperatures over which this glass transition occurs. | 12.5 °C |
| Operating Temperature | -65 - +150 °C |
| UL 94 Rating UL 94 Rating Flammability rating classification. It determines how fast a material burns or extinguishes once it is ignited. HB: slow burning on a horizontal specimen; burning rate less than 76 mm/min for thickness less than 3 mm or burning stops before 100 mm V-2: burning stops within 30 seconds on a vertical specimen; drips of flaming particles are allowed. V-1: burning stops within 30 seconds on a vertical specimen; drips of particles allowed as long as they are not inflamed. V-0: burning stops within 10 seconds on a vertical specimen; drips of particles allowed as long as they are not inflamed. 5VB: burning stops within 60 seconds on a vertical specimen; no drips allowed; plaque specimens may develop a hole. 5VA: burning stops within 60 seconds on a vertical specimen; no drips allowed; plaque specimens may not develop a hole | V-0 |
Additional Information
What are typical applications for ABChimie® 746E UV?
ABChimie® 746E UV is a low viscosity UV-curable conformal coating designed to protect printed circuit board assemblies (PCBs) and components in demanding manufacturing environments, including:
- Automotive electronics (e.g., control units, sensors)
- Industrial automation (e.g., motor drives, PLCs)
- Consumer electronics (e.g., smart devices, wearables)
- Other high-reliability electronic assemblies
Why choose ABChimie® 746E UV?
ABChimie® 746E UV delivers rapid UV curing, excellent electrical insulation, fluorescent under UV light for inspection, and can be solered through without fear of toxic gases being produced. It supports high-throughput manufacturing while providing durable protection for sensitive components.
What is the recommended curing method for ABChimie® 746E UV?
ABChimie® 746E UV is UV-curable and should be cured with a mercury lamp. The minimum UVA dose is 3000 mJ/cm² for a 100 μm thickness. The distance from the lamp to the PCB should be 1-10cm, and the minimum UVA power should be 150mW/cm². Higher UVA doses do not negatively affect final properties, but lower doses will.
Should I control the application environment?
ABChimie® 746E UV should be applied at a minimum temperature of 16°C and a minimum relative humidity of 50%. Before applying, the printed circuit board must be clean, dry, and free of moisture. A stage in an oven at 80°C for 4 hours is usually sufficient.
Learn More About ABChimie® 746E UV
ABChimie® 746E UV is a proven solution for engineers seeking fast, reliable protection of electronic assemblies in demanding manufacturing environments. This UV-curable conformal coating delivers rapid curing, excellent electrical insulation, and strong environmental resistance—ideal for applications in automotive electronics, industrial automation, consumer electronics, and other high-reliability assemblies. It also contains a UV tracer for inspection.
Main Advantages of ABChimie 746E UV
ABChimie® 746E UV cures through a dual mechanism: UV exposure initiates rapid surface curing, while moisture ensures complete curing throughout the coating. This combination provides a uniform, durable protective layer with optimal adhesion and performance.
ABChimie® 746E UV provides excellent mechanical protection. This hardness helps resist scratches, abrasion, and minor impacts, ensuring long-term stability of encapsulated components.
ABChimie® 746E UV can be soldered through without generating highly toxic gases, ensuring safe processing while maintaining coating integrity.
ABChimie® 746E UV provides excellent adhesion even in harsh environments, forming a durable protective layer that resists moisture, chemicals, and temperature variations.
How to Choose a Conformal Coating
Selecting the most suitable resin requires consideration of key factors:
- ✔ Norms & Compliance
- ✔ Environment / Exposure Conditions
- ✔ Repairability
- ✔ Electrical Performance
- ✔ Application Method
- ✔ Operating Temperature
Compliance You Can Trust ✅
ABChimie® 746E UV meets stringent industry standards, ensuring reliability and regulatory adherence for OEMs and contract manufacturers:
- REACH Compliant
- RoHS 2011/65/EU Compliant
UL94 V0
UL746E (QMJU2-E308681)
Curing Tip: ABChimie 746E UV cures with UV rays. Use the appropriate equipment and recommended settings to achieve the best properties.
How to Optimise for the Best Results
PCBs must be completely dry and thoroughly clean, with no dust, grease, wax, or other contaminants. Coating adhesion depends directly on the quality of the substrate. All flux residues must be fully removed, as they can become corrosive and lead to circuit malfunctions.
For cleaning equipment or removing uncured ABChimie 746E UV or UV LED varnish, we recommend using SND or ABclean solvent.
It is essential to use the correct UV equipment (UV or LED) and follow the recommended settings to achieve the optimal properties of the cured conformal coating. ABChimie 746E UV and UV LED cure through UV exposure, with moisture contributing to a secondary curing mechanism.
Curing Mechanism: UV light creates the first cure, and after 7 days the moisture from the environment completes the curing process.
How does Moisture Cure Work?
During UV curing, exposure to UV light activates the photoinitiators in the conformal coating, triggering rapid polymerization of the resin. This results in an immediate surface cure and fast development of handling strength. UV curing provides precise, on-demand curing in exposed areas, enabling high-throughput processing while maintaining coating uniformity.
ABChimie 746E UV and ABChimie 746E UV LED use the same dual curing mechanism to ensure complete curing, including in shadowed or hard-to-reach areas. Initial curing is achieved by UV exposure, while a secondary moisture-activated cure completes the process at ambient temperature. For full curing in shaded areas, a minimum relative humidity of 50% is required for at least 7 days.
Alternative to Mercury Lamp Curing of ABChimie 746E UV
ABChimie 746E UV is also available in the LED lamp curable version.
ABChimie UV LED [Go to 746E UV LED Product Page↗]
- Conformal Coating
- Fluorescent under UV light
- Excellent adhesion to flexible substrates
- Dual curing with UV LED exposure and moisture curing
Best suited for: High-speed process using LED light for curing
