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RTV-2 silicone rubbers SYMSIL type undergo cross linking under influence of a catalyst in a condensation and additive system. Main application areas of this type of rubbers include:
- Decorations, stuccowork: castings, coiling roses, figurines, decorative candles, statues.
- Renovation of architectural monuments: making moulds for monuments, archaeological fossils, etc..
- Ceramics: standards and moulds for artistic, home-based and industrial making of ceramic and porcelain products.
- Artistic products: sculptures, masks, special decorative elements, figurines, bas-reliefs.
- Technology: prototypes and components for leak tests and checking corrosivity.
- Prototyping: making moulds for technical and industrial applications.
- Pad printing: making of pads.
- Shoe making: making moulds for shoe soles, production of artificial leather.
- Metal casting: jewellery, decorative products.
- Electrical engineering: protecting electrical and electronic systems.
Silicone rubbers offered by Symbionis are characterized, among others, by the following features: a wide range of hardness, high tensile strength, resistance to chemical factors, thermal resistance, high relative elongation, small linear contraction and excellent shape representation ability.
Working temperature of a part made of two-component rubber (RTV-2) is within the temperature range from -50°C to +180°C. The Company offers also the rubber which has higher temperature resistance (over 300°C) - SYMSIL T.
The system of cross linking conditions the differences between the rubbers e.g. the rubbers which undergo condensation type cross linking are very insensitive to (resistant to contamination); their vulcanisation time can be only slightly shortened by increasing the temperature. On the other hand, the additive rubbers show considerable increase of vulcanisation rate at an increased temperature. However, the drawback of the additive rubbers is that they are very sensitive to contamination; there is a possibility of „intoxicating” the catalyst by contact with such compounds as: amines, amine compounds, polyurethane, epoxy resins, sulphur, compounds containing sulphur – natural and synthetic rubber. Silicone rubbers are physiologically neutral. They have excellent resistance to UV radiation, ozone and atmospheric factors. Due to their light colour, possibly their transparency, they are easily dyed to any colour.
They also have very good gas permeability and are characterized by good electrical properties. Electrical resistance is about 1015 Ω/cm; resistance to breakdown is approximately 20 kV for 1 mm plate. It is possible to obtain rubbers having a hardness from 21 to 65° ShA and a density from 1.1 to 1.25 g/cm3.
In comparison to organic rubber, the silicone rubber shows very small viscosity in a room temperature. It is characterized by good mechanical parameters: tensile strength from 1 to 8 MPa, relative elongation from 100 to 650 %, linear contraction from 0.1 to 2.5 %. The last of the above-mentioned parameters is of particular importance when negatives of very small parts are made. Lower linear contraction enables more precise representation of a given part. Silicone rubber is in increasing demand in those areas of application where good dampening characteristics and a very high rubber compressibility ratio are required.
In electrical engineering the rubber is used as a noise dampening element between winding and a core in some types of transformers.
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