Tonsan® 1521 White is a two-component adhesive that can cure quickly at room temperature, providing excellent sealing and bonding. This material is recommended for potting electronic components, particularly junction boxes on PV modules. It has good thermal conductivity and flame retardancy.

Product Type: 2K (2 component) Adhesive, Encapsulant, Potting Compound

Application Area: Blades, Edge Gluing, Energy Storage, Frame Sealing, Ingot Bonding, Lithium-Ion Battery, Module Installation, PV J-Box Potting, PV Modules, Rail Bonding, Turbines

Chemical Family: Silicones

Features: Excellent Dielectric Properties, Fast Cure, Flame Retardant, Good Thermal Conductivity, Good Weather Fastness

Technical Data Sheet
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Enhanced TDS

Identification & Functionality

Features & Benefits

Applications & Uses

Application Area
Cure Method
Application Instructions
  • Part A should be blended thoroughly before mix with Part B in order to make filling material distribute evenly.
  • Mix evenly according to the ratio.
  • Pot the mixed material.
  • Recommended using automatic dispensing equipment to applying the potting compound.

Recommended cure: 21- 25°C, 45 - 55%RH for 7 days


Physical Form
Black viscous liquid
Electrical Properties
ValueUnitsTest Method / Conditions
Volume Resistivity1.0 x 10¹⁵Ω.cmGB/T 1692
Breakdown Strength23.0kV/mmGB/T 1695
Technical Data
ValueUnitsTest Method / Conditions
Mixed Density1.4g/cm³GB/T 13354
Volumetric Mix Ratio4:1--
Weight Mix Ratio6:1--
Thermal Service Range- 50 - 150°C-
Thermal Conductivity0.3W/m.KDIN EN 821
Viscosity2500 - 3500cP-
Curing Speed (Gel time)max. 60min-
Cured Properties
ValueUnitsTest Method / Conditions
Flash Pointmin. 93°CGB/T 5208
Working Time (for viscosity min. 30000 mPa·s)8.0min-
Gel Time (Glue does not flow)60.0min-
Hardness40.0-GB/T 531, Shore A
Tensile Strength1.2MPaGB/T 528
Elongation at Break110.0%GB/T 528
Damp Heat Aging Test Properties
ValueUnitsTest Method / Conditions
Volume Resistivity (at 85°C, 85% RH, 1000h)1.0 x 10¹⁵Ω.cmGB/T 1692
Rheological Properties
ValueUnitsTest Method / Conditions
Viscosity (Resin)7000.0mPa.sGB/T 2794
Viscosity Activator25.0mPa·sGB/T 2794
Viscosity (Mixed)3000.0mPa·sGB/T 2794

Packaging & Availability

Country Availability
Regional Availability
  • Africa
  • China
  • Europe (Excluding Russia)
  • India
  • Middle East
  • North America
  • South East Asia

Storage & Handling

Shelf Life
6 Months
Storage Condition

Product shall be ideally stored in a cool, dry area in unopened containers at room temperature. Keep away from children.