additives | Clarifiers and nucleators
Right: Clarified PP is displacing A-PET in
thermoformed packaging
applications such as
prepared foods
claims. Prime among these is glass-like transparency (it says the days of thermoformed polypropylene applications with a milky appearance are over) and a glossier appearance than that normally associated with standard nucleated polypro- pylene. NX UltraClear PP is also said to offer a significantly lower density than alternative options. For NX UltraClear PP to achieve the
same stiffness as A-PET, the PP sheet typically must be 15–20% thicker compared to virgin A-PET sheet, Milliken says. However, opting for a ribbed or improved design can often obviate the need for additional thickness. PP is also known to be easy to seal, with standard PP sealant films still sealing well even when residue is left on tray edges and exteriors during filling. Furthermore, NX UltraClear PP is well suited to production of thermoformed cups and trays requiring good high- and low-temperature resistance.
Blow moulding A variant of Millad NX 8000 has been tailored for use in extrusion blow moulding. Milliken says this Millad NX 8000E grade performs significantly better in higher MFR grades of PP, and yields very good results in both optics and productivity. This nucleator has been designed specifically for use in standard Ziegler-Natta polypropylene EBM resins. “We worked for several years with machine manu-
Below: Emerald’s
Kalama sodium benzoate nucleator being studied in its Netherlands lab
facturers, resin producers, converters and brand owners to optimise this new product, to ensure it delivered the desired properties without compromising transparency or machine production speeds,” says Milliken Senior Development Engineer Bart Gabriels. The optical properties of Millad NX 8000E resins also are less dependent on processing, he says. Standard
mould surface finishes (such as a glass-blasted finish) and processing temperatures for PP can be used without
compromising quality. Gabriels adds that NX 8000E cannot only enable PP
to replace PET, PVC and PC in various blow moulding applications, but can also enable processors to develop new glass-replacement applications such as easy- squeeze bottles. Tests conducted using two clear bottles of the identical size and design – one made of PET, and the other of Millad NX 8000E-clarified PP – also showed that the additive enables bottles to empty their contents much faster, and more completely. Milliken remains alone as a major supplier of
nonitol-based clarifiers, but rivals are offering the market alternative products. At NJC Europe, managing director Liam Killough says the company (part of New Japan Chemical) has put considerable marketing effort into Rikafast EDX, introduced a little over a year ago. “This product is extremely effective in high-MFR PP random copolymers across a wide processing window (190°C – 230°C),” he says. “Also, the yellowness index is extremely low. Blind visual tests have shown that EDX is preferred to the nonitol.” Killough claims Rikafast EDX yields better haze at
addition rates of around 2,000 ppm. “Feedback has been very encouraging and it is expected that several commercial grades [of PP containing the additive] will be launched in Europe and the USA in the latter part of 2017,” he says. “Because the chemistry of Rikafast EDX is based on
acetal sorbitol chemistry there are none of the incom- patibility issues associated with nonitol chemistry and downtime between campaigns is not an issue,” Killough claims.
Nucleating PP Nucleating agents optimise productivity by accelerating crystallisation and, by yielding smaller crystal sizes, they enhance stiffness. Sodium benzoate in particular
52 COMPOUNDING WORLD | May 2017
www.compoundingworld.com
PHOTO: MILLIKEN
PHOTO: EMERALD KALAMA
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90
