materials feature | Additives for polyolefins
Agricultural films have to withstand weathering and aggressive pesticides
The growing use of PP in packaging presents special
challenges for antifog additives, both in thermoformed hot-fog applications and in PP film cold-fog applica- tions. In such cases, very efficient chemistries are required to provide sufficient additive migration. One option is to use glycerol esters and Danisco recom- mends its Grindsted PGE 909 product for PP copolymer blown film and PP cast film used in cold-fog applica- tions. The Grindsted PS 426 grade performs well in PP cast film for hot-fog applications.
Analysing antioxidants Antioxidants are a fundamental property enhancer for all polyolefins and a number of new developments in this arena were discussed at the conference. Norner has recently led research into the effect of
service conditions on antioxidants – the work has been carried out in collaboration with Sintef, Nexans and BrederoShaw as part of the DePA (Demanding Polyole- fin Applications) project. Harry Øysæd of Norner explained that they have
focused on the performance of PP coatings for oil and gas pipelines, where the pipes require direct electrical heating to avoid the formation of hydrate and wax inside. The specification is a 25 year service life at tempera- tures up to 115o
C and at a sea depth of around 350 m.
Different types of PP block copolymer were tested including a 25% glass fibre grade. The results showed that discoloration was affected by wet or dry conditions, time and water depth. Chemical analysis using HPLC and GC revealed the antioxidant consumption in the different types of PP under various conditions. For example, there was a 57% consumption of one antioxi- dant in the glass fibre-reinforced PP during processing. There was a significant effect of raising the sea water pressure conditions (simulating depth) on the loss of
20 COMPOUNDING wORLD | January 2012
some antioxidants. However, Øysæd concluded that the researchers think it is possible to choose a PP formula- tion with the right antioxidant composition to fulfil the requirements for a 25-year service lifetime. Dr Michael Davies of Dover Chemical discussed its
latest liquid phosphite stabilizers at the Polyolefin Additives conference. LGP-11 is a high molecular weight molecule with low migration, is biodegradable, contains no alkylphenols, and has process and hydro- lytic stability. The patent pending technology is claimed to offer better performance than typical commodity phosphites such as TNPP and SP1. Cytec presented its recent Cyasorb Cynergy UV
stabilisation developments. Dr Giacomo Vitarelli explained that these are aimed at agricultural, automo- tive and rotomoulding applications. For example, Cynergy A400 has been optimised for agricultural film applications, including mulch and solarization films, geotextiles based on PP or PE, plus greenhouse film covers with up to two years service life. It resists pesticides and fumigants while providing superior thermal stability and high light transmission. Targeted at automotive applications, Cynergy V703 is designed to offer higher solubility to help reduce blooming, fogging and VOC release. It also provides improved UV stabilisation and paint adhesion together with reduced gas fading and minimised salt formation. Cynergy R300 is aimed at rotomoulding applications
and protects the resin during compounding, grinding, moulding and outdoor service. Supplied in a dust-free, easy-to-disperse, granule form, it provides thermal protection, a broad processing window and excellent colour control under NOx exposure (gas fading). UV performance can be tuned via loading levels. R315 is used in PE applications with a UV 20+ rating, while R350 is for PP durable products with UV10+ rating.
www.compoundingworld.com
s
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
