additives feature | Film applications
Tosaf recently expanded its application
technology lab which includes this lab-scale co-extrusion blown film line
and PolyOne’s Color & Additives business has led to a new solution addressing the twin needs of convenience and high product visibility through the packaging. It brings together a transparent peelable grade of polyole- fin, designed for the peel layer on multi-layered food packaging, with a new generation of the OnCap anti-fog additive masterbatch from PolyOne. Target applications include easy-peel lidding films on rigid and semi-rigid containers for fresh and processed meat, fish, ready-to- eat meals, and fresh produce. The polypropylene packaging grade from Borealis, Borpeel WD955CF, is said to provide consistently high levels of peelability and transparency. It can seal to and peel from itself or other PP grades. PolyOne’s new OnCap anti-fog has global food contact approval, with no specific migration limit (SML) in Europe. It is easily integrated into formulations for cast or blown films, and obviates the need for corona treatment to achieve an anti-fog effect. It also enhances the transparency of the film.
Anti-blocking agents Adhesion between film layers is a common occurrence in film production and converting. Bright, fine minerals are commonly used as anti-blocking additives to reduce that adhesion, and there is considerable competition between materials such as talcs and silicates, as well as synthetic silica. Addition rates normally range from around 500 to 10,000 ppm in polyethylene film grades. Imerys Talc’s Mistroblock range of talc products is based on a very bright micro-lamellar talc ore that the company says provides better overall film properties (optics and mechanical properties, as well as anti- block) than conventional, highly lamellar talc ore. It consists of blocky particles which are more similar in shape to other minerals used for film anti-blocking. In comparative tests with rival anti-block additives in a low-density polyethylene, Mistroblock demonstrated
Fruit packed in film with antifog by PolyOne
reblocking force values comparable to those of conventional talc and performed better than synthetic silica and talc/feldspar.
Imerys also points out that while the hardness and
abrasiveness of some anti-blocking minerals can create excessive wear on extrusion equipment, talc is the softest mineral on earth and the least abrasive. Mistroblock provides higher film clarity and lower film haze compared to conventional, lamellar talc. In addition, tests on metallocene LLDPE film have shown that Mistroblock gives similar haze levels and better clarity than synthetic silica, Imerys claims. Mistroblock has a very strong affinity with the PE film matrix. Imerys says this results in an increase in tensile strength and elongation at maximum force. “Other minerals and talc/mineral blends do not give the same beneficial effect,” the company says. A few months ago, Trinity Resources introduced Alti-
block, an anti-block produced from the company’s pyrophyllite (hydrous aluminium silicate) deposit in Newfoundland, Canada. “Talc, nepheline syenite (NS) and diatomaceous earth (DE, which normally comprises 80-90% silica) have been the incumbent high-perfor- mance anti-block minerals in plastic films for a long time,” says company CEO and president John Hurley. “The morphology of our Altiblock combines the best attributes of talc, NS and DE into one product.” Pyrophyllite is a hydrous aluminium silicate mineral.
According to Trinity, it offers a natural blend of talc-like platy particles and irregular, blocky particle shapes to provide optimal blocking, clarity, film strength, barrier
30 COMPOUNDING WORLD | January 2015
www.compoundingworld.com
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