Wacker ELASTOSIL® RT 402 – Antistatic Condensation Silicone for Pad Printing & Printing Pads

Premium Antistatic Condensation Silicone for Professional Pad Printing and Printing Pad Applications

Wacker ELASTOSIL® RT 402 is a pourable, condensation-curing two-component silicone rubber that vulcanizes at room temperature (RTV-2). The rubber base is processed with 3 wt% Catalyst T 12 and reaches a very low Shore A hardness of 11 with a light gray final color. The low mixed viscosity of 13,000 mPa·s ensures excellent flowability and self-deaeration. Its distinguishing feature is the antistatic finish, which rapidly dissipates static charge from the surface of the printing pad. With a working time of approximately 75 minutes and a curing time of 5 hours at room temperature, this is a reliable system for producing antistatic pads for industrial pad printing.

Key Benefits

• Very soft Shore A 11: – an exceptionally supple rubber that delivers optimal ink transfer in pad printing on irregular and complex surfaces.
• Mixed viscosity 13,000 mPa·s: – very good flowability and self-deaeration, flowing effortlessly into fine mold details.
• Antistatic finish: – rapid dissipation of static charge, essential when printing sensitive electronic components such as CPUs.
• Pot life approx. 75 minutes at 23°C: – ample working time for careful pouring, even with larger printing pads.
• Tear strength > 3 N/mm: – resistant to mechanical stress during repeated use of the pad.
• Adjustable hardness with AK 35: – adding Wacker Silicone Fluid AK 35 lowers the Shore A hardness for even softer printing pads.

Typical Applications

• Production of antistatic printing pads (tampons) for industrial pad printing.
• Printing sensitive electronic components such as CPUs, switches and sensors.
• Printing keyboards, control panels and displays.
• Printing toys, sporting goods and plastic automotive parts.
• Printing porcelain, promotional items and other irregular surfaces.

Processing Instructions

1. Stir the rubber base (component A) thoroughly in its container to evenly distribute any settled fillers.
2. Weigh out 3 wt% Catalyst T 12 based on the total mass (rubber base, or base plus silicone fluid). Example: 100 g base + 3 g T 12.
3. When diluting with Wacker Silicone Fluid AK 35: first mix the rubber base and fluid thoroughly, then add the catalyst.
4. Mix slowly and thoroughly in a figure-8 motion to minimize air entrapment until a homogeneous, streak-free mass is achieved.
5. Pour the mixture within the pot life of approximately 75 minutes, slowly and from a single point into the mold.
6. Allow to cure for approximately 5 hours at room temperature (23°C / 50% rel. humidity). Higher temperature and humidity accelerate condensation curing.

Dilution and Hardness Adjustment

The hardness can be lowered by adding Wacker Silicone Fluid AK 35. The dilution chart shows the Shore A and Shore 00 hardness at increasing oil percentages.

Important Safety Information: Catalyst T 12

Note: The rubber base ELASTOSIL® RT 402 itself is not classified as a hazardous substance and requires no GHS labeling; only general industrial hygiene regulations apply. The supplied Catalyst T 12, however, contains a tetraorganotin compound, is flammable (flash point > 50°C) and may cause irritation to eyes and skin on contact. When processing the catalyst, wear protective gloves and eye protection, ensure adequate ventilation and store the catalyst under lock. Refer to the safety data sheet for Catalyst T 12 for complete instructions.

About the Manufacturer

Wacker Chemie AG is a world market leader in the development and production of silicones for industrial and technical applications. Comprehensive processing instructions are available in the Wacker brochure ELASTOSIL® – PROCESSING RTV-2 SILICONE RUBBERS.

Professional Support

Need advice on the right hardness, dilution or processing for your pad printing application? Feel free to contact us – our specialists are happy to help you choose and process the right material.