TECHNOLOGY | WIRE AND CABLE
Adins range of flame-retardant synergist additives, which are based on a new technology using natural silicates. The company says these offer tailored performance benefits and make it possible to replace part of today’s highly-loaded flame retardant systems. The Adins Clay range includes Adins Clay 20, Adins Clay 80T and Adins Clay Sil-1. Adins Clay 80T, in particular, has demonstrated a strong impact in smoke and heat release and is currently marketed for thermoplastic matrices and rubber in cable applications. Adins Clay Sil-1 is used in silicone and PVC formulations to deliver reduced heat release and smoke suppression and can allow levels of antimony trioxide (ATO) to be reduced. Another new product for ceramifying cable materials is Adins Clay G1, which is based on natural silicates and low melting glass. Tolsa says the Adins Clay and Adins Fireproof additives are based on surface-modified silicates (Adins Fireproof is a ceramifying additive doped with low melting glass). The synergists can be used in combination with several commonly used flame retardants, including metal hydroxides, intumes- cent systems and halogenated flame retardants. The products are compatible with a range of polymers including EVA, PVC, PP, PE and PA, as well as rubbers such as EPDM. Even at low dos- ages, the company says the Adins Clay and Adins Fireproof additives deliver high performance,
Table 1. Basic properties of an ethylene butyl acrylate (EBA) copolymer cable sheathing compound containing different Brucite+ Ecopiren magnesium hydroxide (MDH) flame retardant fillers
Formulation Polymers EBA
mLLDPE, MFI 3.5 LLDPE-g-MAH
Fillers Ecopiren 3.5 Ecopiren 3.5C Ecopiren3.5NP
Processing aids and stabilisers TOTAL, %
Properties MFI at 190°C, 21.6 kg, g/10min LOI, O2%
Tensile strength, MPa Elongation at break, % Source: Europiren
22 1 %
24 5 5
63 63 3 100
4.1 49
13.5 71
COMPOUNDING WORLD | May 2021 3 100
0.8 45 11 67
63 3
100
2.5 50 14 77
2 %
24 5 5
3 %
24 5 5
including anti-dripping effect, improved char mechanical properties, reduced heat release and smoke suppression. Tolsa says that its technology allows the silicate to be functionalised with different modifiers, compounds or particles to improve the efficiency of the system so that improved performance can be achieved with less flame retardant additive. The company says it is working closely with leading wire and cable manufacturers to develop new applications in the automotive and electrical/ electronic industries, for example, as well as developing specific additives for PA and silicones.
Lifting performance Germany’s Nabaltec developed its Actilox PA-B2 additive masterbatch for producers of HFFR cable compounds. Described as a flame retardant booster, it is claimed to reduce pressure build-up during compounding and extrusion without compromising mechanical performance and ageing characteristics. It is said to be easy to blend with any mineral-based fillers and shows synergistic effects with ATH in terms of flame retardancy (Nablatec offers a range of ATH fillers in its Apyral product line).
Minimising the negative impact of the high filler loadings on processing in HFFR cable formulations is also the goal of Innospec Leuna, which has developed an organic processing aid that it claims improves the dispersion of ATH and MDH, as well as carbonates and silica-based nano-materials. Viscospeed is a polar additive that is intended to improve wetting and dispersion of the inorganic filler particles and prevent re-agglomerating during processing. The company adds that the additive preserves elongation at break and ageing charac- teristics, while flame retardance is enhanced through improved char formation and reduced dripping tendency. Europiren — the distributor of Brucite+ high purity magnesia products from the Russian Mining Chemical Company — has investigated ethylene butyl acrylate (EBA) copolymer as a new base for halogen-free flame retardant (HFFR) cable com- pounds. Similar to an ATH-EVA combination, EBA and magnesium hydroxide (MDH) display close thermal decomposition points – 300-330°C for MDH and greater than 350°C for EBA. Europiren’s polymer laboratory has studied a
series of HFFR formulations based on EBA filled with Ecopiren MDH. The first step included full replace- ment of EVA by EBA in a classic cable sheathing compound. Ecopiren 3.5 treated with stearic acid (C), alkylsilane (NP) and without surface treatment
www.compoundingworld.com
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