company tower banner
Wacker Chemie AG Company Logo

SEMICOSIL® 942 UV A/B

1 of 27 products in this brand
SEMICOSIL® 942 UV A/B is a sprayable, addition-curing, two-part silicone rubber with low viscosity. This product cures extremely fast when exposed to UV light, resulting in a soft conformal coating. SEMICOSIL® 942 UV A/B exhibits low viscosity and shear-thinning properties, making it suitable for spray applications. It offers the advantage of extremely fast curing at room temperature after UV activation, as well as the ability for shadow curing. Additionally, it contains a UV tracer, providing process control options during application.

Chemical Family: Silicones

Product Type: 2K (2 component) Coating, Conformal Coating, Encapsulant, Potting Compound, Radiation Curable Coating

Cure Method: Air Dry, Chemical Cure, Radiation Cure

Application Area: Electric Vehicle (EV) Batteries, Printed Circuit Boards

Application Method: Spray

Technical Data Sheet

Knowde Enhanced TDS

Identification & Functionality

Chemical Family

Features & Benefits

Labeling Claims
Ready-to-Use Product Features

Applications & Uses

Application Method
Applications
  • Automotive Electronics
  • Electrics & Electronics
  • Power Electronics
Application Details
  • To ensure homogeneity component A must be stirred thoroughly before processing.
  • Surface preparation All surfaces must be clean and free of contaminants that will inhibit the cure of SEMICOSIL® 942 UV A/ B. Examples of inhibiting contaminants are sulfur containing materials, plasticizers, urethanes, amine containing materials and organometallic compounds – especially organotin compounds. If a substrate’s ability to inhibit cure is unknown, a small scale test should be run to determine compatibility.
  • Handling : The A-component contains an UV-tracer that is dispersed in the silicone. The UV-tracer may be subject to a limited sedimentation. In order to guarantee homogenous product performance (curing time, UV-tracability) it is recommended to homogenize the A-side prior to application by stirring.
  • Mixing : Component B of SEMICOSIL® 942 UV A/B contains an organometallic and a platinum catalyst, component A the crosslinker. Even traces of the catalyst may cause gelling of the component containing the crosslinker. Therefore tools (spatula, stirrers, etc.) used for handling the catalyst component or the catalyzed compound must not come into contact with this component. The two components should be thoroughly mixed at a 10 : 1 ratio by weight or volume. To eliminate any air introduced during dispensing or trapped under components or devices a vacuum encapsulation is recommended.
  • Curing For the curing an UV lamp (Fe-lamp, D-bulb) with an emission between 250 and 350 nm can be used. It is recommended not to use lamp systems that emit light with a wavelength below 250 nm. 1 space line
  • Curing time of SEMICOSIL® 942 UV A/B is highly dependent on UV-activation, Significant differences in curing time are obtained for curing different layer thicknesses and for using different substrate materials. Typical values are given below.
  • UV-activation Curing time (140 mW/cm²) at 25°C (2mm) 1 s 5 min 5 s 2 min 20 s cured after 20 s UV
  • Without UV-activation SEMICOSIL® 942 UV A/B cures at room temperature within 48 h at 70 °C within 15 min.


Processing 

  • General
    • SEMICOSIL® 942 UV A/B is intended to be used only for processing in dispensing equipment configurations with direct mixing of SEMICOSIL® 942 UV A and B in the mixing tube (.i.e. after the dispensing head).
    • It is not intended to be applied in premixes that are stored in separate reservoirs or distribution systems. Pot-Life after mixing has to be considered.
       
  • Surface
    • All surfaces must be clean and free of contaminants that will inhibit the cure of the 10:1 mixture of SEMICOSIL® 942 UV A/B .
    • Examples of inhibiting contaminants are sulfur containing materials, plasticizers, urethanes, amine containing materials and organometallic compounds – especially organotin compounds. If a substrate’s ability to inhibit cure is unknown, a small scale test should be run to determine compatibility.
       
  • Handling
    • SEMICOSIL 942 ® UV B is supplied in specific packagings allowing the material transfer to reservoirs of state-of-the art dispensing equipment without exposure to ambient light. For this purpose a reusable opening fixture is mounted on the can closure Informations can be provided by the regional sales managers.
    • To ensure homogenity of the corresponding A component, usually the addition curing silicone SEMICOSIL® 942 UV A must be stirred thoroughly before processing.
    • Typically also SEMICOSIL® 942 UV B is stirred in the reservoir of the dispensing machine. Dissolved air is removed by standard degassing of reservoir contents.
    • After exposure to ambient light or daylight SEMICOSIL® 942 UV B should be immediately processed and not stored any longer.
       
  • Mixing
    • SEMICOSIL® 942 UV B contains the organometallic UV active catalyst, the corresponding component A the crosslinker. Even traces of the catalyst may cause gelling of the component containing the crosslinker. Therefore tools (spatula, stirrers, etc.) used for handling the catalyst-containing component or the catalyzed compound must not come into contact with this component.
    • SEMICOSIL® 942 UV A should be thoroughly mixed with SEMICOSIL® 942 UV B at a 10 : 1 ratio by weight or volume. Typically static mixing with tube configurations 24/6 or higher (increased no. helical turnings or lower diameter) are sufficient.
    • To eliminate any air introduced during dispensing or trapped under components or devices a subsequent vacuum encapsulation may be recommended.
       
  • UV Cure
    • UV Irradition on SEMICOSIL® 942 UV B activates the UV-active catalyst. In combination with SEMICOSIL® 942 UV A a very fast cure can be achieved. Cure speed can be tuned in typical ranges between minutes and seconds depending on UV Intensity and dose.
    • Direct Cure : Reaction proceeds after end of UV irradition. Main cure is rapidly achieved for those areas irradiated with UV light.
    • Shadow Cure : areas not directly accessible are cured on longer time scale by second addition curing mechanism (see gel time no irradiated)
    • For the curing an UV lamp (Fe-lamp, D-bulb) with an emission between 250 and 350 nm can be used. It is recommended not to use lamp systems that emit light with wavelengths below 250 nm. An high power UV-LED may also be used (365 nm) for applications allowing minimum distance to the light source. As light penetration depth is reduced 365 nm in UV-LED in comparison with discharge lamp pretests are recommendable to check feasibility for specific application.
    • Curing time of SEMICOSIL® 942 UV A/B (10:1) is highly dependent on UV-activation. Significant differences in curing time are obtained for curing different layer thicknesses and for using different substrate materials.

Properties

Typical Properties
ValueUnitsTest Method / Conditions
Mix Ratio10:1 parts by weight
Catalyst Properties
ValueUnitsTest Method / Conditions
Dynamic Viscosity (at 25°C, Shear rate 0.5 s⁻¹)3200mPa·sDIN EN ISO 3219
Dynamic Viscosity (at 25°C, Shear rate 100 s⁻¹)420mPa·sDIN EN ISO 3219
Gel Time (irradiated, 120 mW/cm², 10 sec)3minutesDIN 16945
Gel Time (not irradiated, at 25°C)max. 48hoursDIN 16945
Gel Time (not irradiated, at 70°C)20minutesDIN 16945
Mix Ratio10:1parts by weight
Pot Life (at 23°C)approx. 6 hours
Cured Properties
ValueUnitsTest Method / Conditions
Density (at 23.0°C)0.98g/cm³DIN EN ISO 2811-2
Penetration (at 23°C, Cure: 10sec, 120 mW/cm² followed by 30 min, 150°C)6mmDIN ISO 2137
Volatile Contentmax. 350ppm
Uncured Properties
ValueUnitsTest Method / Conditions
Density (at 23°C, Componenet A)0.98g/cm³DIN EN ISO 2811-2
Density (at 23°C, Componenet B)0.97g/cm³DIN EN ISO 2811-2
Platinum Catalyst in Component (Organometallic catalyst + Pt catalyst)Component A
Platinum Catalyst in Component (Organometallic catalyst + Pt catalyst)Component B
Viscosity (at 25°C, Component B)1000mPa·sDIN EN ISO 3219
Viscosity (at 25°C, Shear rate 0.5 s⁻¹)3300mPa·sDIN EN ISO 3219
Viscosity (at 25°C, Shear rate 0.5 s⁻¹)450mPa·sDIN EN ISO 3219
Properties
  • Coating and encapsulant for printed circuit boards
  • Dispensing and spraying applications
  • Two-part, 10 : 1 mixing ratio
  • Low viscosity, shear thinning
  • Extremely fast curing at room temperature (after uv-activation)
  • Shadow curing at room temperature
  • Offers process control option by uv-light (contains uv-tracer)
  • Low and constant moduli (-40°c to +180°c) [storage modulus 10 kpa, 1hz/25°c]
  • Protection of housed pcbs with cover (sticky gel)
  • IEC 60664-3:2017 compliant, positive sir testing (electromigration free)
  • IPC-CC-830C compliant
  • Low ion content (Cl-, Na+, K+, Li+, each <= 2 ppm)

Regulatory & Compliance

Certifications & Compliance

Packaging & Availability

Country Availability
Regional Availability
  • Africa
  • Asia
  • Europe
  • Latin America
  • Middle East
  • North America
  • Oceania

Storage & Handling

Storage Information

General recommendations SEMICOSIL® 942 UV A/B should be stored in the original light-tight container. After exposure to daylight or UV-light the material should be immediately processed and not stored any longer.