The general properties of the main materials being used are summed up below:
Polyvinyl chloride (PVC)
the PVC-U (« unplasticised ») is one of the oldest and the most used plastic material in the industry and in consumer products. This amorphous thermoplastic presents good mechanical characteristics, does not react to humidity and is dimensionally very stable at room temperature.
This material is the most widely used material in the valve industry and plastic piping, thanks to its good chemical behaviour at moderate temperature (0-60°c) and its low cost.
This material, which can be bonded and welded, presents however a low shock resistance and can not withstand UV light, which limits its use in various applications. It is the same for its moderate thermal behaviour and we would rather use chlorinated polyvinyl chloride (CPVC), which with its superior density presents a greater range of thermal behaviour (up to approximately 90°C).
Because of the presence of chlorine in the PVC, its use is more and more contested. In this case, it is often replaced by ABS or PP.
The ABS is a copolymer of Styrene and Acrylonitrile linked to Polybutadiene. The good chemical resistance of the Acrylonitrile is combined with the shock behaviour properties and flexibility of the polybutadiene, giving a materiel presenting excellent characteristics between -40°C and +70°C.
This material is widely used in all applications on drinking water and foodstuffs, thanks to its non-toxicity and the absence of chloride. This material, presents an excellent resistance to abrasion, has the advantage to be welded, such as the PVC
SAFI's Glass Fibre Polypropylene (GRPP)
One of the most used material by SAFI. This polypropylene contains 20% of borosilicate glass fibres of type « C chemically resistant. It has a very good mechanical resistance, a good dimensional stability, can be easily machined and It is resistant to temperatures up to 100°C. Its resistance to UV is improved by the addition of carbon pigments and UV stabilizers. An antioxidant additive improves its resistance to the oxidizing chemicals
Anti-Static Polypropylene (ASPP)
This material contains 20% carbon fibre and conducts electricity. It is used in explosive zones where anti-static materials are compulsory. It enables our whole product range of SAFI products to comply with zones 1 and 2 ATEX regulation
Polyvinylidene fluoride (PVDF)
The vinylidene polyfluoride is a vinylidene fluoride polymer. Its English name being « PolyVinyliDene Fluoride explains its ISO code: PVDF. The PVDF is a highly resistant thermoplastic. Such as other fluorinated polymers, it supports temperature variations, ultra-violets and more corrosive chemical agents. The PVDF is a homopolymer without additives (stabilizing standards for example), non toxic, has a particularly smooth surface, which avoids the development of micro-organisms For these reasons, the PVDF is regularly used with foodstuffs, water pipelines or in drug and semiconductor industries, even if its principal applications are in chemistry, taking into consideration its very good anti-corrosive properties.
SAFI selected a highly crystalline grade of PVDF, produced by suspension. This grade has a very good mechanical resistance, as well as a great long-term stability at high temperature. Moreover, this grade presents the advantage of being resistant to wet chlorine.
The main advantages of the PVDF are as follow
Anti-static polyvinylidene fluoride (ASPVDF)
This PVDF contains carbon powder enabling it to conduct electricity It is used in explosive zones where anti-static materials are compulsory and allows SAFI’s products made with this material to be used in ATEX zone 1 and 2
|- % Fibre||-||%||20 (glass)||0||0||20|
|- Density||D 792||g/cm³||1.04||1.78||0.9||1.41||1.02|
|- Rupture stress||D 638||MPa||55||50||35||48||75|
|- Tensil Rupture Stress||D638||Mpa||3137|
|- Elongation at break||D638||%||3||40||200||-||2.5|
|- Flexural rupture stress||D 790||Mpa||70||94||35||90||95|
|- Flexural modulus||D 790||Mpa||4200||2500||1200||4900|
|- Resilience, IZOD impact test||D 256||J/m||80||100 to 200||-||76|
|- Hardness, Rockwell R||D 785||105||115||30||112|
|- Hardness, Shore D||D 785||74||77 to 82||-||70|
|- Heat deflexion temperature 18.5 kg/cm2||D 648||°C||125||115||52||74|
|- Vicat softening point under 5kg||D 1525||°C||140||147||152|
|Linear expansion coefficient, 0 to 100°C||D 696||10 /°C||6||11||13|
|Surface Resistance||ASTM D257||ohm||10|
|Resistance to tracking||NF C 26-220||V||270|