Material developments in thin wall packaging

Thin-walled plastics packaging is used in a wide range of industries including dairy containers like yogurt cups, yellow fats, frozen foods, fruit and vegetables, bakery, ready meals, juices, soup and meats. Recently it has also found application in glass and can replacement for commodities like meat and preserves, which reduces weight and opens up design opportunities. The Thin Wall packaging market is composed of open-top containers and lids that are used in both food and non-food applications. Open-top plastic containers are typically used for frozen or fresh food, paint, adhesives, cosmetics, pharmaceuticals. Some of the developments in materials for this process include:
Borealis� BorPure™ random polypropylene (PP) copolymers with improved organoleptics. BorPure™ RJ766MO is intended primarily for transparent injection moulded, thin walled food packaging. Its excellent organoleptic properties mean that it will not impart taste or odour to the packaged product. This is the product of a combination of Borstar� PP polymerization technology and Borealis Nucleation Technology (BNT). Together these technologies produce a material with a tailor-made molecular weight distribution (MWD) and crystalline structure resulting in fast crystallisation and a good balance of stiffness and impact properties. Energy savings are also achieved thanks to the material�s excellent flow characteristics, which enable processing equipment to run at lower temperatures than is possible with many competing materials with sufficient organoleptic properties. With its high melt flow rate of 70, BorPure RJ766MO now brings energy saving advantages to containers with even the thinnest walls. Borealis' material grades provide benefits such as:
� increased throughput for converters due to reduced cooling time and high flowability
� design freedom for the brand owner to create new, complex packaging shapes
� superior stackability through high stiffness and excellent creep properties to reduce supply chain costs and improve efficiency
� excellent transparency which lets consumers see through the packaging while providing safe storage and easy opening
Borpact SG930MO is perfectly suited for high transparency, deep freeze applications like ice cream packaging, where no compromise must be made between transparency and high impact resistance. It achieves a drop test at -20°C of 2 meters versus 10 cm for standard transparent polypropylene MFR 20 (1.2 mm wall thickness, 700 ml filled). RJ470MO is ideally suited for transparent consumer packaging requiring very good flow. For a 15 g container with wall thickness of 0.38 mm, we can achieve an 11% reduction in cycle time versus an MFR of 45.It also has an excellent combination of mechanical properties, providing high stiffness while maintaining good impact resistance. BJ356MO is a heterophasic polypropylene with excellent flow characteristics for demanding applications and provides a step change in flow and impact balance, meeting the demand for lightweight products with high stiffness. Despite its very good flow, BJ356MO has low taste and odour characteristics and a white based tint. This makes it perfect for portion pack thin wall food containers such as 250 g margarine tubs.

SABIC has added grades for thin-wall injection moulding applications with a new impact copolymer, Sabic PP Flowpact FPC 100. This was typically developed for the production of containers for yellow fats and packaging for dairy products such as yoghurts, cream, flavoured milk and cheese spreads. The material contains a state-of-the-art package of processing and antistatic additives. It is distinguished by high flow and high crystallisation speed, which together result in reduced cycle times and potential savings in unit costs at converters, particularly in thin-wall packaging. The energy that can be saved will also have knock-on benefits for related environmental considerations. a new impact copolymer grade. With this, SABIC has two impact copolymers and one homopolymer in its Flowpact range. As with existing grades SABIC® PP FPC55 and SABIC® PP FPH50, the new grade contains a state-of-the-art package of processing and antistatic additives. It is distinguished by high flow and high crystallisation speed, which together result in reduced cycle times for moulders. It also features an excellent balance of impact strength and stiffness. SABIC® PP Flowpact FPC 100 has a melt flow rate (MFR, 230°C, 2.16 kg) of 100 g/10 min, enabling easy production using multicavity moulds running at high speed. Concerning food packaging, the new grade is in compliance with EFSA regulations.

NATPET has unveiled high-clarity polypropylenes for thin-walled packaging and injection molded containers. Noticeably increasing demand towards very high clarity packaging articles at reasonable price has led National Petrochemical Industrial Co. (NATPET) to upgrade its range of polypropylene random copolymers to introduced two new grades in its Teldene range, both containing Milliken's Millad NX 8000 latest-generation clarifying agent. They are aimed principally at markets for thin-walled injection molded food and non-food containers, especially in Europe, Turkey, the Middle East, and Asia. As living standards improve in emerging markets, end-users are putting increasing emphasis on aesthetics when buying products such as food storage containers. The new grades cater for this demand. Additional advantage of this grade by virtue of having Millad NX 8000 is that it enables the converters to achieve added benefit of considerable energy and cost savings (value for price) by processing the grade at lower temperatures and cycle times than by similar products in the market. The two new grades, Teldene R25MLT and R40MLT, have melt flow rates of 25 and 40 g/10 min respectively. Mechanical properties are very similar, but Teldene R40MLT, with higher flow, is better suited for complex products and high-speed machines. Parts molded with these grades have excellent optical properties; at a thickness of 1 mm, the Haze value is just 6%, compared with 15-20% in grades containing conventional clarifiers when processed at low temperatures. This is attributed to the highly improved solubility of Millad NX 8000 in PP. Injection molders can therefore make significant energy savings and reduce cycle times (decent cost and time savings), while still obtaining articles with outstanding optical characteristics. Reduced energy consumption also means a lower carbon footprint, an environmental factor of thoughtful significance. Processors using the new grades can reduce ecological Carbon Dioxide generation by 5-8%.
Prospects for developments in material are very bright. End users as well as converters in our target markets are very appreciative of the improved aesthetics, cost and time savings, and wider processing window achievable with the new grades.