materials feature | Additives for PET
ver, is a plus for recycling. One major challenge in reusing PET is that reclaimed material loses clarity during recycling, especially if it is part of a commingled stream, as happens when PET bottles use polyolefi n closures or seals. In commenting on the dual benefi ts of Amosorb Plus in oxygen scavenging and clarity, Gary Fielding, director of market- ing for ColorMatrix, says: “Incorporating additives during production that do not
PET bottles often use polyolefi n closures, which can create mixed streams of recyclate
year were its Amber Masterbatch grades. Developed primarily for pharmaceuticals, but applicable to any product in need of an effective light barrier – food, beverages, cosmetics and even toys – the materials reportedly provide desired colour results in natural PET resins at low loadings, thereby improving process economy. The company says that factors in the effectiveness of
the four grades in the Sukano T line include high masterbatch concentrations, precise colour-matching technology, and formulations tailored for specifi c applications. Loadings range from 2 to 5%. Target applications are moulded parts and bottles, oriented fi lms, solid sheet, fl at and cut fi lms, and thermoforming fi lms. The materials comply with European Pharmaco- poeia and USP Class VI rules for pharmaceutical use.
Controlling oxygen A critical barrier technology for PET packaging is oxygen scavenging. ColorMatrix, which is a subsidiary of PolyOne, commercialized Amosorb Plus last year, an upgraded version of the additive that additionally maintains optical clarity and minimizes haze in beverage containers and other applications. The material is described as a crystallized PET-
based concentrate with a built-in catalyst that promotes oxidation. The additive is formulated to provide foods and non-carbonated beverages such as fruit juices with six months or more of shelf life, depending on package design. This level of performance can be tailored to optimize package specifi cations for maximum economy in production and shipping. For example, if a popular drink such as a fruit juice needs much less than six months of shelf life, Amosorb Plus is tailorable to permit packages to be thin-walled or otherwise designed to reduce PET use and lower weight. It may also give companies a reason to convert to PET from glass or aluminium packaging, both of which would, in comparison, be over-engineered alternatives. The ability to improve and maintain clarity, moreo-
60 COMPOUNDING WORLD | March 2014
negatively affect PET clarity and quality contributes to a greener recycling stream by signifi cantly enhancing recyclability. I think we will see more solutions in the market designed to improve the quality of reclaimed PET, increasing its potential for use in container, fi lm and sheet applications.” Another benefi t of the additive is that it is based on
technology that has already been approved for food use by regulators in various parts of the world. As a result, it doesn’t require a new set of regulatory approvals, making it a virtual drop-in replacement for compound- ers that use the original Amosorb additive. ColorMatrix unveiled Amosorb Plus at Chinaplas 2013. China is one of the world’s largest producers of PET food and beverage packaging, and the properties of the additive are particularly relevant to that market, for the impact they could have on packaging design strategies and recycling. One company that applied a proprietary oxygen
barrier technology to an additive is resin producer Invista. The company’s PolyShield MB masterbatch is based on PolyShield PET barrier resin technology. Karsten Fritsch, PET resins business manager, says the masterbatch is formulated for foods and beverages that are especially sensitive to oxygen and loss of carbon dioxide. Targets include beer, where the masterbatch can be used in monolayer containers when blended with standard PET resin and, for added barrier protection, MXD6 polyamide from Mitsubishi Gas Chemical. Containers moulded from such a blend reportedly achieve a 15% improvement in carbon dioxide barrier and reduce oxygen permeability to less than 1 ppm/year. Fritsch adds that the barrier performance of
PolyShield MB broadens the material sourcing fl exibility of converters and brewers, which can yield savings in freight and duties. The additive is available globally, except in the US.
Simpler packaging Additive suppliers are addressing an evolving trend: reducing barrier layers in PET packaging. This is being driven by efforts among converters to lower processing costs and package complexity, consolidate product
www.compoundingworld.com
PHOTO: POLYONE
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