STYCAST 2651-1

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

STYCAST 2651-1

Main features

  • One-Component Production Handling
  • -40 to 155 deg C Service
  • Thermal-Shock-Resistant Electronic Encapsulation

Product Description

LOCTITE STYCAST 2651-1 One-Component Epoxy Encapsulant is a black, one-component medium-viscosity filled epoxy for heat-cured encapsulation of small electrical and electronic assemblies. The ready-to-use material has a typical viscosity of 52,000 cP and avoids component mixing, supporting controlled production handling. Cure options range from eight hours at 80 deg C to four hours at 120 deg C, followed by a recommended post-cure for final property development. The cured encapsulant provides electrical insulation, 0.58 W/(m K) thermal conductivity, thermal-shock resistance, and an operating range of -40 to 155 deg C.

Key features

  • One-component handling: The ready-to-use formulation removes mix-ratio and catalyst-selection steps.
  • Heat-cure flexibility: Multiple cure schedules from 80 to 120 deg C support production planning.
  • Wide operating range: The cured system is documented for service from -40 to 155 deg C.

Applications

Applications include heat-cured encapsulation of small electrical and electronic assemblies requiring insulation, thermal-shock resistance, and a one-component process.

Product Family

STYCAST 2651-1

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TDS, SDS & Technical Documents

Technical Specifications

Physical Properties
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
52,000 mPa.s
General Properties
Density (g)
1.6 g/cm3
Other Properties
Storage Temperature
25 °C
Chemical Properties
Water Absorption
0.1 %
Thermal Properties
Thermal Conductivity
Thermal conductivity describes the ability of a material to conduct heat. It is required by power packages in order to dissipate heat and maintain stable electrical performance. Thermal conductivity units are [W/(m K)] in the SI system and [Btu/(hr ft °F)] in the Imperial system.
0.58 W/m.K
Electrical Properties
Arc Resistance
ASTM-D495 expresses arc resistance as the number of seconds that a material resists forming a surface-conducting path when exposed to a high-voltage, low-current arc occurring intermittently. Results obtained from a nominal 3 mm thickness are meant to represent the material’s reaction in any thickness.
182 s
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.
17.3 kV/mm
Volume Resistivity
Volume resistivity, also called volume resistance, bulk resistance or bulk resistivity is a thickness dependent measurement of the resistivity of a material perpendicular to the plane of the surface.
1×10¹⁵ Ohms⋅cm

Additional Information

Technical properties

As-supplied / before-processing properties

Property Value Unit Method / condition
Product form One-component black filled epoxy Ready to use
Viscosity 52,000 cP 25 deg C; Brookfield, spindle 7, 20 rpm
Specific gravity 1.6 Typical as supplied
Shelf life 90 days 25 deg C
Cure schedule 8 h at 80 deg C; 6 h at 100 deg C; 4 h at 120 deg C Typical options
Post-cure 2-4 hours 150 deg C
Process mass guidance Approximately 50 g No adverse exotherm observed at 120 deg C up to this mass
Technical properties

After-processing / final-state properties

Property Value Unit Method / condition
Operating temperature -40 to 155 deg C Cured material
Hardness 88 Shore D Typical cured value
Coefficient of thermal expansion 45 x 10^-6 per deg C Typical cured value
Linear shrinkage 0.002 cm/cm Typical cured value
Water absorption 0.1 % 24-hour boil
Thermal conductivity 0.58 W/(m K) Typical cured value
Dielectric strength 17.3 kV/mm Typical cured value
Volume resistivity 1 x 10^15 ohm cm 25 deg C

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