Two new masterbatches from Clariant offer long-lasting protection against oxygen (O2) and carbon dioxide (CO2) permeation in polyethylene terephthalate (PET) bottles. Offered under the CESA®-absorb brand name, the new masterbatches use a combination of ingredients that remains stable during handling and processing and avoids the need for special nitrogen (N2) treatment, which is often required when using other oxygen absorbers. The new additive masterbatches are being featured in Hall B3, Booth 112 at Drinktec 2009, the World Fair for Beverage and Liquid Food Technology being held in Munich, Germany, September 14 to 19.
CESA-absorb OCA0050134-ZN is an all-in-one masterbatch that incorporates a polyamide (PA) polymer additive that forms a passive barrier to help prevent CO2 escaping from bottles filled with carbonated soft drinks and beer. The additives, as active ingredients, also initiate an oxidation reaction in the PA so that it absorbs oxygen and thus, protects sensitive products inside the bottle. This masterbatch is typically added with let-down ratios of 4 or 5%.
CESA-absorb NTA0050139-ZN does not include PA in the masterbatch, allowing processors to control loading by introducing the PA separately. Added at a rate of just 1 to 1.5%, the CESAabsorb masterbatch then functions with the PA just as it does in the all-in-one product.
Both products can be supplied as combibatch, incorporating not only the additives for oxygen reduction and CO2 barrier, but also UV stabilizers, acetaldehyde scavengers and, of course, color. Since certain colorants and pigments can inhibit the functionality of other additives a tailor-made combibatch solution can be a substantial benefit for processors, who can be assured that it is formulated for maximum effectiveness and color development.
The reaction initiated by CESA-absorb to prevent oxygen permeation develops over several weeks after processing. It oxidation reaction does not start immediately as this is the case with several other oxygen absorbers. Thus, there is no need to keep the masterbatch itself in sealed containers or to use equipment that surrounds the molded preforms and bottles with nitrogen. “With CESAabsorb, processing equipment is less complex,” explains Ruggero Facchinetti, Clariant Head of Additive Masterbatches for Europe South and Special Markets. “You don’t need to have a supply of nitrogen and handling of the masterbatches and molded preforms is much simpler. The barrier properties of bottles developed when using CESA-absorb allow our products to compete with more conventional products.”
Laboratory testing on bottles produced with the recommended let-down ratios of CESA-absorb shows that O2-barrier properties of CESA-absorb begin developing about three to four weeks after processing and reach their full potential in about 5 weeks. Oxygen transmission then remains close to zero for at least six months. Tests also show very little loss of clarity when using these masterbatches with PET colorants.
Clariant Masterbatches supplies a complete range of additive masterbatches for PET. CESA additive masterbatches are available in a wide variety of physical forms, from large cylindrical granules (2.5 by 4.0 mm) to spherical nanogranules that are just 0.6 to 1.5 mm in diameter. Liquid masterbatches, which can be used at very low let-down ratios with excellent color distribution, are often a good solution for transparent colors. In general, masterbatches are easier to handle and mix more readily with the matrix material than neat additives. Compared to pre-compounded resins, natural plus masterbatch can be less costly and can allow processors more flexibility to change colors and adjust additive loading.
Clariant Masterbatches products are marketed under the following global brand names: REMAFIN® olefinic masterbatches and compounds; RENOL® masterbatches and compounds based on engineering resins, styrenics and PVC; CESA® additive masterbatches; HYDROCEROL® chemical foaming and nucleating agents; OMNICOLOR® universal color masterbatches. These brand names are all registered trademarks of Clariant.
| Ruggero Facchinetti Head of Additives for Europe South and Special Markets Phone: +39-02-9918-7577 ruggero.facchinetti@clariant.com |
