polyamides | Additives
Adur. Applications include wear-resistant injection moulding compounds, extrusion of pipes and tubes, and blow moulded components for automotive engine compartment applications. He also said that producers of impact-modified PA 6 and 66 can improve DTUL and mechanical properties and retain impact properties at the same or lower cost.
Combined improvements Normally when impact modifiers are compounded in polyamide, the tensile strength, DTUL and flexural modulus drops while elongation and impact strength goes up, Adur notes. “With a combination of an impact modifier like
Figure 1: Spiral flow of a PA6 containing 20% modifier. The sample on the left contains a standard modifier and flow length is 29.2cm. The sample on the right contains Paraloid EXL 3815 from Dow Plastics Additives and flow length is 36.3cm
ZeMac is available as a powder, aqueous solution and in masterbatch pellet form. Companies currently purchasing expensive high
viscosity polyamides produced by solid state polymeri- sation can use ZeMac to produce grades with similar viscosity by compounding at lower cost, according to
[DuPont’s] Fusabond N493 with ZeMac Extend master- batch, the compounder can adjust the properties to get values of all the properties in between at about the same net cost,” he says (see Table 2). ZeMac additives also increase the hydrolysis resistance of polyamides used with glass fibre reinforcement to mitigate their breakdown in the presence of moisture, heat and glycol- based antifreeze. Nexam Chemical, which offers modifiers for a wide
range of polymers, says its technology enables improvements in properties such as viscosity, melt
Table 1: Effect of ZeMac upgrading additives from Vertellus Specialties on key properties of various PA6 grades Off-spec
Property
Tensile Strength at yield, MPa Tensile Elongation at break, MPa Flexural Modulus, MPa
Charpy Impact Strength @ 23°C, kJ/m2 Charpy Impact Strength @ -30°C, kJ/m2 Melt Flow Rate @ 235°C, 1 kg. g/10 min Source: Vertellus Specialties
Test method ASTM D638
ASTM D-790 ISO-179-2/2
ASTM D123
PA 6 61.1 9.5
2385 33.8 24.7
13.03
Off-spec PA 6 with 0.75% ZeMac E60 P
80.8 21.0 2942 38.0 29.6 0.48
Virgin PA6 83.6 12.4 2796 33.2 22.3 9.65
Table 2: Effect of a combination of Zemac upgrading additive with impact modifier on key properties of recycled and virgin PA6 grades Formulation of Compound, %
ASTM D638 Tensile
Recycled Virgin PA6 ZeMac Extend ZeMac Extend Fusabond PA6
PA6 100
90.05 90.0
100 90 90
Source: Vertellus Specialties 20 COMPOUNDING WORLD | February 2016
www.compoundingworld.com 2.5
10.0 7.5
2
10 8
M600 M601 N493 Strength
at yield, MPa 63.60 55.62 58.70 79.12 65.72 68.93
Tensile elongation Flexural 12.38
2640.0 1966.7 2300.8 2850.1 2315.4 2457.9
ASTM D790
ASTM D256 Izod impact
strength at
at break, % modulus, MPa 23°C (ft-lb/in) 17.21 12.60 61.59 4.08 8.09
1.30 7.73 14.5 1.25 8.83 8.20
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