Chemically inert food grade (PC) silicone oil for moulds, lubrication and defoaming
Silicone Oil 350 cSt is a medium viscosity, colourless and chemically inert polydimethylsiloxane (PDMS) fluid with a viscosity of 350 cSt and a density of 0.970 g/cm³ at 25 °C. With a flash point above 300 °C, a pour point of -50 °C and a surface tension of 21.1 mN/m, this oil offers a good balance between fluidity, film retention and stability. The 350 cSt grade is the most widely used grade for softening silicones: fluid enough to mix evenly, viscous enough for a lasting film.
This oil is supplied in PC grade (food grade) from AToro. According to the manufacturer's declaration of compliance, this grade complies with EC 1935/2004, FDA 21 CFR 173.340 and FDA 21 CFR 177.2600, among others. See the Compliance section below for the full list.
Key benefits
- ✓ Flash point above 300 °C: a high flash point makes the oil safe to handle and store. For the maximum service temperature, observe the note on thermal stability below.
- ✓ Viscosity 350 cSt at 25 °C: the most widely used grade as a silicone additive, with a good balance between mixability and lasting film retention on moulds and surfaces.
- ✓ Pour point -50 °C: stays fluid at low temperatures, suitable for applications in cold environments.
- ✓ Surface tension 21.1 mN/m: wets surfaces very well and spreads evenly as a release film on moulds and dies.
- ✓ Food grade (PC) according to the declaration of the manufacturer: suitable as a defoamer (FDA 21 CFR 173.340) and in food contact applications, within the conditions of the regulations listed.
- ✓ Chemically non reactive: does not react with addition or condensation silicones, most plastics and elastomers, so it is safe as an additive without unwanted side reactions.
Typical applications
- → Release agent for rubber, polyurethane, epoxy and metal die casting, leaving a lasting release film on complex mould surfaces
- → Additive for addition and condensation silicones (1 to 10%) to lower hardness and increase flowability
- → Defoamer in non aqueous systems, effective in small amounts
- → Lubricant for plastic and elastomer surfaces, without attacking the material
- → Electrically insulating fluid and damping fluid in electrical and electronic equipment
- → Smoothing spatula applied silicone moulds by hand, the 350 cSt viscosity spreads easily by hand or brush
Processing as an additive in silicones
- Weigh the required amount of component A of your silicone and add component B according to the specified mixing ratio.
- Stir the mixture thoroughly.
- Add the silicone oil to the silicone mixture and stir again. Use 1 to 10% oil based on the total weight. Adding about 8% lowers the Shore A hardness by roughly 3 to 5 points.
- Stay below 10%: more oil can reduce the final strength of the cured silicone to an unacceptable level.
- Process the mixture within the pot life of your silicone.
⚠️ Note: silicone oil does not cross link in the silicone and can slowly bleed out under sustained stress or over time, leaving a greasy film on the mould. Take this into account for moulds used over a long period.
⚠️ Thermal stability: in the presence of air, polydimethylsiloxane slowly starts to degrade above approximately 150 °C and can release formaldehyde, among other substances. Ensure good extraction or ventilation for applications above 150 °C.
Compliance
According to the declaration of compliance of AToro B.V. (23 April 2024) for Silicone Fluid DM PC, the 350 cSt PC grade complies with:
- → EC 1935/2004 and EU 10/2011 for materials and articles intended to come into contact with food
- → BfR Recommendation XV Silicones
- → French Arrêté of 25 November 1992 for materials in contact with food
- → FDA 21 CFR 173.340, defoaming agent as a secondary direct food additive
- → FDA 21 CFR 177.2600, rubber articles intended for repeated use
- → FDA 21 CFR 175.300, 176.210, 175.105, 176.170, 178.3120 and 177.1210, use in the manufacture of food packaging up to 10 ppm, subject to limits on extractables
- → Listed under E 900 polydimethylsiloxane
This is a declaration by the manufacturer, not a certificate. National regulations in the country of use continue to apply. For food contact, you as the user are responsible for the compliance of your finished product. The declaration of compliance is available on request.
Professional support
Not sure which viscosity suits your application, or do you have questions about using silicone oil in food contact? Contact us at info@siliconesandmore.com for technical data sheets, the declaration of compliance or product advice.
