COOLTHERM 6403

Harmonization Code : 3910.00.00.90 | Silicones in Primary Forms; Others

COOLTHERM 6403

Main features

  • 900 cP Mixed Viscosity
  • 45-Minute 25 deg C Cure
  • 50 to 120 deg C Service Range

Product Description

Circalok™ 6403 A SLW / B Urethane Encapsulant is a general-purpose, two-component urethane system for electrical and electronic encapsulation applications requiring fast cure and resistance to mechanical shock. The amber liquid components mix at a 22:10 resin-to-hardener ratio by weight and produce a mixed viscosity of 900 cP at 27 °C. The encapsulant can be poured or applied with automatic meter/mix/dispense equipment and cures in 30–45 minutes at 25 °C or 5–10 minutes at 100 °C. Once cured, it provides electrical insulation, moisture resistance, hydrolytic stability, and an operating temperature range of -50 to 120 °C.

Key features

  • Low mixed viscosity: Provides a typical mixed viscosity of 900 cP at 27 °C for pouring or automated meter/mix/dispense application.
  • Fast, heat-accelerated cure: Cures in 30–45 minutes at 25 °C or 5–10 minutes at 100 °C, with complete cure in 2–3 days at 25 °C.
  • Electrical and environmental protection: The cured urethane provides electrical insulation, moisture resistance, and hydrolytic stability.

Applications / Suitable for

  • General-purpose electrical and electronic encapsulation
  • Encapsulated assemblies requiring fast cure and resistance to mechanical shock
  • Parts and devices operating from -50 to 120 °C
Product Family

COOLTHERM 6403

Catalog Product

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TDS, SDS & Technical Documents

Technical Specifications

General Properties
Color
Amber Liquid
Physical Properties
Viscosity (Part A)
750 mPa.s
Viscosity (Part B)
1200 mPa.s
Electrical Properties
Dielectric Strength
0.6 kV/mm
Volume Resistivity
1 x 10^14 Ohms⋅cm

Additional Information

Technical properties

As-supplied / before-processing properties

Typical properties of the separate components and mixed encapsulant before cure. Values are not intended for specification purposes.

Property Value Unit Method / condition
Appearance Amber liquid — 6403 A SLW resin, 6403 B hardener, and mixed material
Mix ratio 22:10 By weight 6403 A SLW resin : 6403 B hardener
Viscosity — resin 750 cP 6403 A SLW resin at 27 °C; test method not stated
Viscosity — hardener 1,200 cP 6403 B hardener at 27 °C; test method not stated
Viscosity — mixed 900 cP Mixed material at 27 °C; test method not stated
Specific gravity 0.96 / 1.19 / 1.04 — Resin / hardener / mixed material; test conditions not stated
Gel time 10–15 minutes Mixed material; test temperature and method not stated
Shelf life 6 months Each component, from date of manufacture; stored at 25–40 °C in the original unopened container
Technical properties

After-processing / final-state properties

Typical properties of Circalok 6403 A SLW / B after mixing and cure. Values are not intended for specification purposes.

Property Value Unit Method / condition
Cure time 30–45 minutes At 25 °C; complete cure in 2–3 days at 25 °C
Heat-accelerated cure time 5–10 minutes At 100 °C after the material reaches the target temperature
Operating temperature range -50 to 120 °C Parts and devices; retained-property data across the full range are not stated
Hardness 80 Shore A Cured material; test method and cure condition not stated
Tensile strength 1,935 psi Cured material; test method and cure condition not stated
Dielectric strength 600 V/mil Cured material; specimen thickness and test method not stated
Volume resistivity 1 × 1014 Ω·cm ASTM D257 at 25 °C
Dielectric constant 3.6 — At 25 °C and 1 kHz

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