BOSTIK THERMELT 858

Harmonization Code : 3214.10.00 | Putty and other mastics | Resin cements, caulking compounds and other mastics

BOSTIK TMELT 858

Main features

  • High-Temperature Low-Pressure Encapsulation
  • UV- and Moisture-Resistant Encapsulation
  • Black-Only Thermelt Grade

Product Description

Bostik Thermelt 858 Black is a black-only polyamide hot melt resin for low-pressure encapsulation of electronic components and assemblies. The one-component grade combines very good thermal stability with UV and moisture resistance. Its operating range is -40 to 150 deg C, Shore D hardness is 40/32 measured immediately and after 15 seconds, and the softening point is 180 +/- 5 deg C. Thermelt 858 Black fits low-pressure molded electronics requiring a defined black material together with high-temperature, UV, and moisture resistance.

Key features

  • Thermal stability: The grade operates from -40 to 150 deg C with a 180 +/- 5 deg C softening point.
  • UV and moisture resistance: The grade has very good UV and moisture resistance for low-pressure molded electronics.
  • Black-only grade: Thermelt 858 is available in black only within the Thermelt molding range.

Applications

Low-pressure molding, encapsulation, and protection of electronic components and assemblies.

Product Family

BOSTIK THERMELT 858

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TDS, SDS & Technical Documents

Technical Specifications

Physical Properties
Drying Time
8 hours
Softening point (Melting point)
175-185 °C
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
4,000-6,000 mPa.s
Thermal Properties
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.
-35 °C
Mechanical Properties
Elongation
Elongation is the process of lengthening something. It is a percentage that measures the initial, unstressed, length compared to the length of the material right before it breaks. It is commonly referred to as Ultimate Elongation or Tensile Elongation at break.
340 %
Chemical Properties
Water Absorption
1.9 %

Additional Information

Technical properties

Final-state properties

PropertyValueUnitMethod / condition
Operating range-40 to 150deg CGrade operating range
Shore hardness40 / 32DISO 868; instant / 15 s
Softening point180 +/- 5deg CASTM D3461

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