Premium Silicone Oil Plasticizer for Professional Mold Making and Viscosity Applications

Wacker AK 350 is a linear, non-reactive polydimethylsiloxane (silicone oil) with a kinematic viscosity of approximately 350 mm²/s. The oil is added to pourable addition and condensation silicones to make the cured rubber softer and more flexible, and to thin the uncured mixture for better de-aeration and detail reproduction. The colorless, odorless liquid has a density of 0.97 g/cm³, a high flash point of 260 °C, and a low surface tension of 0.021 N/m. Dosing is done by weight, typically between 1 and 15 percent relative to the silicone mixture, with more oil resulting in a softer end product and less oil maintaining the original hardness. The primary application is to custom-adjust the hardness and flowability of mold rubbers.

Key Benefits

• Viscosity 350 mm²/s – thin fluid oil that can be easily and homogeneously mixed with addition and condensation silicones
• Density 0.97 g/cm³ – precisely dosed by weight between 1 and 15 percent for controlled hardness reduction
• Hardness reduction approximately 3 to 5 Shore A at 8 percent – predictable softening without making the silicone unusable
• Flash point 260 °C – high thermal safety margin during processing and storage
• Low surface tension 0.021 N/m – improves the flow of the silicone mixture so it penetrates better into fine details and crevices
• Infinitely miscible with all Wacker AK silicone oils – any desired intermediate viscosity can be set

Typical Applications

• Softening pourable addition and condensation silicones for more flexible molds
• Viscosity reduction of molding rubber for better de-aeration and detail reproduction
• Smoothing applied silicones by hand using wiping and spatulating techniques
• Release agent and lubricant in industrial and technical applications
• Water repellent and defoaming agent
• Liquid dielectric and heat transfer oil for electrical applications

Processing

1. Prepare your silicone: mix the A and B components in the correct weight ratio according to the technical data sheet of the respective silicone and stir thoroughly first.
2. Add the Wacker AK 350 oil by weight. Dosing between 1 and 15 percent; approximately 8 percent gives a noticeable softening of about 3 to 5 Shore A points. More oil softens further, but above 10 percent, the final strength may decrease unacceptably.
3. Mix until completely homogeneous, ensuring the oil is evenly distributed throughout the silicone mixture.
4. Pour or process the mixture within the pot life of the silicone used.
5. Allow to cure according to the curing time and temperature of the silicone used.

Wacker Chemie AG is a global market leader in the development and production of silicones for industrial and technical applications.

Special Instructions

Adding silicone oil is a form of customizing your silicone. Please note that the final values will deviate in certain aspects from the values on the technical data sheets of the silicones. The oil does not cross-link within the silicone, meaning that over the years and under stress, it will slowly exude, leaving a greasy film and causing the mold to shrink slightly.

Food Contact

Wacker AK 350 formally complies with Regulation EU 10/2011 and is listed as polydimethylsiloxane (E 900) on the positive list. However, Wacker explicitly advises against its use as a food additive; the substance has no technological effect in food. Suitability for a specific food contact material must always be determined by the manufacturer of the end product.

Shelf Life

At least 5 years when stored below 50 °C in a dry, cool, and tightly closed container.

Professional Support

Are you unsure about the correct dosage for your specific silicone or application? Feel free to contact us; we are happy to help you optimize hardness and flowability.