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BLUESIL ESA 7250 B

BLUESIL ESA 7250 B

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Optically clear, high-strength 2K-Pt silicone potting compound for electronics potting, optoelectronics — mixing ratio 10:1.

Optically clear, high-strength 2K-Pt silicone potting compound (Shore A 52) for electronics potting, optoelectronics, and photovoltaic cells

Price on request

  • Container
  • Curing type
  • Consistency
  • Cured Color
  • Self-leveling
  • Electrical Insulation
  • Food contact
  • Medical grade
  • Uncrosslinked viscosity (mPa·s)
  • Mixing Ratio
  • Pot life (min)
  • Tensile strength (MPa)
  • Elongation at break (%)
  • Tear strength (N/mm)
  • Manufacturer
  • Number of components
  • Mixing Ratio
  • UV resistance
  • Brand

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Silicone ESA BLUESIL 2K silicone ELKEM Swiss bearing addition platinum catalyst 1:1 silicone gel electronic encapsulation optically clear

 
General Terms and Conditions

Shipping usually within 1 to 3 business days
(Availability confirmed after order)

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From Swiss stock Dispatch within 24h Batch certificate Invoice 30 days (B2B) Technical advice
Shipping & Delivery

Usually 1 to 3 business days

Availability is confirmed after order receipt.

Express logistics within Switzerland & Europe.

Terms and Conditions →

Product data

HS Code: 39100000

HS Code: 39100000

BLUESIL ESA 7250 B
BLUESIL ESA 7250 B
Bluesil · Elkem Silicones ·

Bluesil ESA 7250 A & B is an optically clear, high-strength 2K-Pt silicone potting compound (Shore A 52) for electronics potting, optoelectronics, and photovoltaic cells.

This product range comprises 2K polyaddition silicone elastomers with optical clarity for electronics encapsulation, optoelectronics, and photovoltaic cells — defined refractive index, high transparency. ESA 7250 is tailored to specific industrial applications — the key properties and areas of use are listed below.

High strength + optically clear

Bluesil ESA 7250 combines excellent mechanical properties (6.2 MPa tensile strength, Shore A 52) with optical clarity. 10:1 mixing ratio, 4-hour pot life, refractive index 1.406 — proven industry standard for optoelectronics and high-performance potting.

ESA 7250 in numbers
Optically clear
Transparent
Shore A 52
Hardness
6.2 MPa
Tensile Strength
4 h
Pot life

What sets ESA 7250 apart

Optically clear
Direct visibility of encapsulated components — suitable for visible connections.
High strength (Shore A 52, 6.2 MPa)
Robust vulcanizate — protects mechanically stressed components.
Low-viscosity mixture
4'000 mPa·s — easy to degas and pour.
Long pot life (4 h at 23 °C)
Careful processing even with large volumes.
Definitive refractive index
n=1.406 — suitable for optical applications with index step.
Superior heat resistance
+200 °C for short periods, suitable for many industrial applications.

What is ESA 7250 used for?

Electronics potting
Potting of electronic components with high mechanical protection.
Optoelectronic connections
Optical fiber coating with index step.
Photovoltaic cells
Insulation and protection of solar cells.
Mechanical-optical components
Where transparency AND mechanical strength are required.
Industrial sensor technology
Encapsulation of high-performance sensors.
LED potting
High-performance LEDs with clear optics.
Data Sheets & Safety Data Sheet
Complete TDS and SDS in DE, EN, FR — view or download directly.
To the documents →

Processing

1
Prepare the component
Position the component cleanly and dry in the encapsulation mold. Align the optical axes.
2
Mix A & B
10:1 or 1:1 (see comparison table). Low-viscosity mixture — easy to degas.
3
Degas
30–50 mbar vacuum — important for bubble-free optics.
4
Casting
Slowly pour into the mold — refractive index 1.40 makes the material optically clear.
5
Curing
24–48 h at 23 °C or accelerated with heat up to +150 °C.

Recommended accessories

Bluesil Inhibitor 3
Pot life extender for polyaddition silicone systems (Pt-cure).
To the product →
Bluesil Primer PM 820
High-performance primer for polar plastics (PA, PES, ABS, PP) and composites.
To the product →
Bluesil Primer 131
Universal adhesion promoter for stainless steel, aluminum, PMMA, and many metals.
To the product →

Important Notes

Mixing & Dosing
Stir A and B thoroughly before each processing. Accurate dosing in the specified ratio (see table above) — preferably weight-based. Incorrect dosing leads to incomplete crosslinking.
Degassing
Degas the mixture under vacuum at 30–50 mbar. Material expands 3–4 times, falls back after 5–10 min. Interrupt vacuum several times for better degassing.
Avoid inhibitors
Polyaddition silicones are inhibited by: sulfur-vulcanized rubber, tin-catalyzed RTV, amine epoxides, PVC with tin salts. When in doubt, perform a preliminary test.
Application consulting
SILITECH advises you on the optimal RTV variant for your application — substrate, hardness, pot life, mechanics. Contact us with your specific application case.

ESA 7250 compared with related RTV products

Crosslinking system, mechanics, and processing times directly side by side — all values from the official Elkem-TDS. “— " = not specified in the data sheet.

ESA 7250
Current Product		 RTV 141 →ESA 6110 →RTV 8352 LV →
Crosslinking system2K Polyaddition (Pt)2K Polyaddition (Pt)2K Polyaddition (Pt) Gel2K Polyaddition (Pt)
Mixing ratio10 : 110 : 11 : 11 : 1
ColorOptically clear, colorlessTransparent, colorlessOptically clearWhitish
Shore A hardnessA 52A 50Gel (penetration 250)A 55
Elongation at break115 %120 %—78 %
Tensile Strength6.2 MPa6 MPa—2.3 MPa
Tear strength4 kN/m———
Pot life4 h4 h50 min (Std) / 5 min (QC)130 min
Demolding time24–48 h24–48 h120–180 min8 h
Mixed viscosity4'000 mPa·s4'000 mPa·s1'200 mPa·s2'200 mPa·s
Main applicationElectronics pottingOptoelectronic connectionsElectronics Encapsulation (Potting)Electrical Engineering Encapsulation
Topics & Application Fields
Key terms related to this product. Also useful for our search and filters.
Silicone ESA BLUESIL 2K silicone ELKEM Swiss bearing addition platinum catalyst 1:1 silicone gel electronic encapsulation optically clear

Technical data for BLUESIL ESA 7250 B

All 19 Product Information 8 Further Properties 1 Physical Properties 3 Electrical Properties 1 Curing Values 1 Product Approvals 2 Mechanical Properties 3
Product Information
Container 100 g, 500 g, 2.5 kg
Curing type Addition (Platinum)
Consistency Flowable
Mixing Ratio 10 : 1
Manufacturer Elkem Silicones
Number of components 2K (two-component)
Mixing Ratio 1:1
Brand Bluesil
Further Properties
UV resistance Yes
Physical Properties
Cured Color Transparent
Self-leveling Yes
Uncrosslinked viscosity (mPa·s) 4
Electrical Properties
Electrical Insulation Yes
Curing values
Pot life (min) 4
Product Approvals
Food contact No
Medical grade No
Mechanical properties
Tensile strength (MPa) 6.2
Elongation at break (%) 115
Tear strength (N/mm) 4

Please refer to the technical data sheet (TDS) in the "Documents" tab for binding values.

Documents and data sheets

Click on a document for the preview or the download icon for direct download.

Technical Data Sheets (TDS) 1
Bluesil ESA 7250 B E5 - Technical Data Sheet EN.pdf
653 KB
Safety Data Sheets (SDS) 3
Bluesil ESA 7250 B E5 - Safety Data Sheet DE.pdf
294 KB
Bluesil ESA 7250 B E5 - Fiche de Sécurité FR.pdf
498 KB
Bluesil ESA 7250 B E5 - Scheda di Sicurezza IT.pdf
491 KB

Frequently asked questions about ESA 7250

Practical processing and design questions — answered by SILITECH.

Bluesil ESA 7250 A & B: Optically clear, high-strength 2K-Pt silicone potting compound (Shore A 52) for electronics potting, optoelectronics, and photovoltaic cells. Main applications include electronics potting, optoelectronic connections, and photovoltaic cells.

Polyaddition crosslinking is a 2-component silicone chemistry with a platinum catalyst. Component A contains the platinum complex, component B the SiH crosslinker. When mixed, the components crosslink without releasing reaction by-products — no shrinkage due to outgassing substances, excellent dimensional accuracy, low linear shrinkage. Important: Polyaddition silicones are inhibited by various substances — sulfur-vulcanized natural rubbers, tin-catalyzed RTV silicones, amine-catalyzed epoxy resins, PVC stabilized with tin salts. In case of doubt, a preliminary test must be carried out.

Thoroughly stir components A and B before each processing step. Dose precisely according to the mixing ratio specified in the TDS (see comparison table above) — preferably by weight. Mix with an electric or pneumatic stirrer at low speed (minimize air entrainment). Degas the mixture under vacuum (30–50 mbar) — the material expands to 3–4 times its volume, bubbles escape, and the material settles back after 5–10 minutes. Then pour slowly into the mold from the lowest point to avoid air entrapment. For polyaddition systems, avoid contact with inhibitors (sulfur rubber, tin RTV, amine epoxides, PVC with tin salts).

Store in unopened original container in a dry, cool place — typically between +5 and +30 °C, exact values see TDS. Store components A and B separately; after opening, seal airtight. Polyaddition systems are insensitive to moisture, but should be stored cool to preserve pot life. Consult the Safety Data Sheet (SDS) before use.

In the comparison table above, you will find related RTV products with different hardnesses, pot lives, or application profiles. If you are unsure about the optimal choice, we will be happy to advise you — contact SILITECH with your application (substrate, desired hardness, processing time, requirements for mechanical properties and resistance).

Your question not covered?

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Product Specifications

Product Information
Container 100 g or 500 g or 2.5 kg
Curing type Addition (Platinum)
Consistency Flowable
Mixing Ratio 10 : 1
Manufacturer Elkem Silicones
Number of components 2K (two-component)
Mixing Ratio 1:1
Brand Bluesil
Further Properties
UV resistance Yes
Physical Properties
Cured Color Transparent
Self-leveling Yes
Uncrosslinked viscosity (mPa·s) 4
Electrical Properties
Electrical Insulation Yes
Curing values
Pot life (min) 4
Product Approvals
Food contact No
Medical grade No
Mechanical properties
Tensile strength (MPa) 6.2
Elongation at break (%) 115
Tear strength (N/mm) 4
Keywords
Keywords
Silicone ESA BLUESIL 2K silicone ELKEM Swiss bearing addition platinum catalyst 1:1 silicone gel electronic encapsulation optically clear
Processing
Viscosity of Mixture1’200 mPa·s
Viscosity Comp. A1’000 mPa·s
Viscosity Component B1’200 mPa·s
Pot life at 23°C40.0 min
Physical & Thermal
Density (23°C)0.98 g/cm³
Temperature Resistance (Continuous)-50 to 200 °C
Peak Temperature (Short-term)200 °C
Electrical characteristics
Dielectric constant ε (1 kHz)2.8
Dielectric strength23.0 kV/mm
Volume resistivity1e+15 Ω·cm
Dissipation factor tan δ0.001
Storage
Shelf life in original packaging12 months
Storage Temperature-10 to 30 °C

Documents and data sheets

Safety Data Sheets (SDS) and Technical Data Sheets (TDS) for download: