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CHT Group QSil 553

CHT Group QSil 553 is a 2-component silicone elastomer system specially designed for electronic potting and encapsulation applications. It offers good protection against chemicals, environmental contamination, mechanical shock, vibration, and impact damage. It can be employed in areas where low flammability is a prerequisite. The cured elastomer can be repaired. The component parts have relatively low viscosities and are readily mixed, either by hand or machine.

Product Type: 2K (2 component) Adhesive, Encapsulant, Potting Compound, Solvent free (100% Solids) Adhesive

Application Area: Aerospace Applications, Electronic Control Units, Insulators

Cure Method: Chemical Cure

Chemical Family: Silicones

Technical Data Sheet
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Knowde Enhanced TDS

Identification & Functionality

Chemical Family

Features & Benefits

Key Features
  • 100% solids - no solvents
  • Long pot life
  • Low modulus and good elongation
  • UL94 V0 listed in file No. E205830

Applications & Uses

Cure Method
Application

Electrical insulator, application cars e.g. encapsulation of ABS control unit.

Use and Cure Information

Important

The 'A' part of the product contains the platinum catalyst, great care should be taken when using automatic dispensing equipment. Please ensure that it is not contaminated by residual hydride containing rubber in the dispensing equipment, as curing will result. If in doubt, it’s advised to thoroughly purge the equipment with a suitable hydrocarbon solvent or silicone fluid.

Mixing

Both the ‘A’ and ‘B’ parts should be well stirred to ensure the material is uniform and any settled the fillers have been remixed. Place the required amount of ‘A’ and ‘B’ parts by weight at the mix ratio shown opposite, in a clean plastic or metal container of approximately 3 times their volume, and mix until the color of the mixture is uniform. For best results, we recommend degassing. Degas by intermittent evacuation, the larger volume of the mixing vessel helps prevent overflow during this operation. In the case of automatic dispensing with static mixing head, the two components should be degassed before processing. Recommended vacuum conditions are 30-50 mbar intermittently over 5-10 minutes. Cast the mixture either by gravity or pressure injection.

Inhibition of Cure

Great care must be taken when handling and mixing all addition cured silicone elastomer systems, ensuring that all the mixing tools (vessels and spatulas) are clean and constructed in materials which do not interfere with the curing mechanism. The cure of the rubber can be inhibited by the presence of compounds of nitrogen, sulfur, phosphorus and arsenic; organotin catalysts and PVC stabilizers; epoxy resin catalysts and even contact with materials containing certain of these substances e.g. molding clays, sulfur vulcanized rubbers, condensation cure silicone rubbers, onion and garlic.

Curing Conditions

  • The data offers a guide to the rate of cure at various temperatures, mixing of the components at temperatures between 15 and 25°C is recommended to ensure adequate pot life for degassing and handling. The pot life can be extended to several hours by chiling the components before mixing.
  • It is important to check the compatibility in preliminary tests if unknown substrates are used.

Properties

Flame Rating
Physical Form
Typical Properties
ValueUnitsTest Method / Conditions
Mix Ratio1:1
Tensile Strength250.0psi
Electrical Properties
ValueUnitsTest Method / Conditions
Comparative Tracking Index600.0Volts
Dielectric Constant3.08ASTM D-150
Dielectric Strength500.0V/mil
Dissipation Factor0.009ASTM D-150
Volume Resistivity4.02 x 10¹⁵Ω.cmASTM D-257
Cured Properties
ValueUnitsTest Method / Conditions
Elongation (at Break)240.0%
Hardness Shore A45.0ISO 37
Working Temperature Range-55 - 240°C
Tear Resistance7.8N/mmBS ISO 34-1
Tensile Strength1.72N/mm²ISO 37
Thermal Conductivityapprox. 0.68W/mK
UL File NumberE205830
Mixed Viscosity6000.0cps
Shore A Hardness45.0Durometer
Gel Time140.0Minutes
Uncured Properties
ValueUnitsTest Method / Conditions
De-Mould Time / Full Cure (at 23°C)24.0Hours
Density (Component A)1.63BS ISO 2781
Density (Component B)1.63BS ISO 2781
Viscosity (Mixed)6000.0cPBrookfield
Uncured Product Property
Cure Profile 15 mins at 150°C
Cure Type Addition
Mix Ratio By Weight 1:1
Rheology Liquid

Regulatory & Compliance

Certifications & Compliance

Packaging & Availability

Packaging

CHT Encapsulants are available in a variety packaging including bulk containers.

Storage & Handling

Shelf Life
24 Months
Storage Conditions

Maximum storage temperature is 38 °C / 100 °F