Flame retarded PAs
Exolit OP 1400 is based on organic phosphinate chemistry and has the excellent thermal stability needed for high temperature processing of PAs . It is a free-flowing powder and can be introduced into thermoplastics via traditional processing routes , such as twin-screw extrusion compounding and injection moulding . It can also be used in newer technologies like 3D printing of complex parts . Exolit OP 1400 is compatible with a wide range of PA chemistries , including commonly used aliphatic polymers like PA 6 , 6,6 11 and 12 , to semi aromatic polymers like PA 4T and 6T . It offers a wider processing window , making it easier to compound high temperature PAs . In addition , it reduces the accumulation of any mould deposits during injection moulding operations , which leads to significant reduction in downtimes . As electronic devices become sleeker and run faster , heat generation in these products is often a concern . Exolit OP 1400 can be used in thinwalled connectors up to 0.4 mm , providing ample protection to the device . A distinct feature of Exolit FRs is that they result in lower density moulded parts compared to traditional halogenated FRs . With paradigm shifts like e-mobility for automotive applications , Exolit OP 1400 offers distinct advantages in properties like comparative tracking index ( CTI ), a measure of the insulation properties of a plastic , for PAs . For instance , in glass-reinforced PA 6,6 , CTI up to 600 V can easily be achieved with the use of Exolit OP 1400 .
Recycling flameretarded PAs
More importantly , as the world moves towards a circular economy for a better carbon footprint , it is vital that sustainable materials are available in the future that can be recycled while retaining their original properties . In a recent study , the Fraunhofer Institute in Germany addressed the question of recycling FR-containing electronic devices like computers and laptops , which normally end up in landfills or the incinerator . 1 This showed that PAs containing Exolit OP 1400 can be recycled multiple times , while retaining their flame retardancy characteristics and other properties , like mechanical strength and stiffness . Exolit OP 1400 in glass-filled ( GF ) PA 6,6 materials were subject to multiple extrusion steps for up to five cycles . The granulated material from the first , third and fifth cycles were then injection moulded into test bars for further characterisation . Test bars from these all passed the UL-94 V flammability test with a strong V-0 rating and the mechanical properties of the FR-PA test specimens showed the same reduction as the non-flame retarded formulations . In other words , Exolit OP 1400 did not negatively impair the mechanical properties upon recycling . If anything , the reduction in strength and stiffness was attributed to the attrition of glass fibres during processing . The study also demonstrated that , when the moulded part from each cycle is subject to accelerated heat ageing and tested , the flame retardancy is not affected and the parts exhibited V-0 rating .
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Figure 2 – Properties of Exolit OP 1260 in GF-PBT
1.9 |
2.6 |
2.4 |
1.52 |
1.53 |
1.67 |
600 |
575 |
225
Elongation at break , % Density g / cc CTI , Volts Exolit OP 1240 Exolit OP 1260 BFR / ATO
37