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Frequently Asked Questions (FAQs)

¿How many types of silicone are there?

There are three main types of silicone: silicone oils,silicone rubbers and silicone resins, which in turn include more than one thousand different silicone semiproducts. In Merefsa we work with silicone rubbers through processes such as compression moulding, transfer moulding, extrusion (HTV silicones) and casting (LSR silicones).

¿How long can silicone products last?

The life of a silicone product depends on the working conditions to which it is subjected (temperature, mechanical effort, chemical resistance, etc.). Once vulcanised and transformed into an end-product, they have no expiry date. Kept in their original packaging, these products can last more than 10 years in perfect state.

¿How is the price of an extruded item calculated?

To calculate the cost of an extruded product we need to know: * Number of metres or quantity needed. * Drawing, sketch or sample of the item to manufacture. * Working temperature range. * Any foodstuff related specifications if there are. * Chemical and mechanical working conditions.

¿ Does silicone turn yellow ?

Some do and others don't. A catalyst is added to the silicone raw material (which has a plasticine-like consistency) so it vulcanises and turns it into an end-product. There are three main type of catalysts: * Platinum salts-based catalysts: Make silicone very transparent and not yellow with time or when exposed to sunrays. They are suitable for foodstuff contact. * DIACYL peroxides: they are the least transparent and yellow with time but are suitable for foodstuff contact. * DIALKYL peroxides:: they are quite transparent and yellow little with time, these are mainly used for industrial applications.

If the silicone has turned yellowish, ¿should we discard it?

No, silicone even though it may yellow with time, keeps all its mechanical and chemical properties. We can therefore keep on using it until it breaks or stops working they way we expect.

¿Which colours are manufactured? ¿Which colours does MEREFSA supply?

Whatever colour is needed. Merefsa manufactures to any RAL colour with a minimum order quantity of 25Kg. Our standard is translucent for compact silicone and off-white for sponge silicone. We can also manufacture in luminescent,fluorescent and metallic colours.

¿What temperatures can silicone withstand?

Our standard silicone withstands from -50ºC up to +200ºC, but we have other silicones that can withstand -90ºC (PVMQ) and even +315ºC (THT). Our silicones are guaranteed by the manufacturer for continuous use of at least 1,000 hours.

¿Which hardnesses are made? ¿Which hardnesses does MEREFSA make?

Our standard for compact silicone is 65 Shore A, and 0.25gr/cm3 for sponge silicone. Our range of hardness for compact silicone goes from 25 to 85 Shore A and the density range is from 0.25 up to 0.8gr/cm3 for sponge silicone.

¿Does MEREFSA sell mixed compounds to third parties?

Yes. Although our main activity is the manufacturing of end-products we also sell ready-to-use catalysed compounds.

¿Can you make urgent orders in 24 hours?

Yes, for our standard compact silicones there is an extra charge of 150€ for production line changes, applicable to coloured or translucent silicones with hardness from 40 to 80 Shore A.

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