When developing a customized rollstock structure for barrier packaging applications, factors including food product, part design, processing conditions, distribution environment and retail conditions must all be considered as each variable ultimately affects shelf-life performance. Once these variables have been defined, further details such as barrier specifications, shelf-life expectations, part geometry, material attributes and part handling must all be considered to refine the design of the thermoformed part and develop a rollstock structure that will deliver optimal barrier performance.
Depending on the end-use application and barrier requirements, ICPG can formulate customized coextruded barrier rollstock structures using substrates such as polystyrene, polypropylene, and polyethylene combined with high barrier materials for oxygen and moisture protection to meet application requirements.
High Impact Polystyrene:
High Impact Polystyrene (HIPS) is a form of polystyrene (PS) that carries with it a higher impact strength. Homopolymer PS can often be brittle, and can be made more impact resistant when combined with other materials. This form of PS typically is produced by adding around 5-10% rubber or butadiene copolymer. This increases the toughness and impact strength of the polymer and results in a very stiff product ideal for packaging applications. Use of HIPS is prevalent in food and medical thermoforming and form fill seal packaging due to its low cost and easy processability. However, with the implementation of Proposition 65, use of HIPS in food packaging applications is declining.
Polypropylene:
Polypropylene (PP) is a semi-crystalline polymer that is hazy in its natural state, but can be made available as an exceptionally clear and high-gloss material through the use of specialty additives and processes. This material is generally characterized as having a higher stiffness at a lower density, resistance to higher temperatures, and an excellent strength to weight ratio. There are three main grades (homopolymer, random copolymer and impact copolymer) of PP resin which allow for improvement of specific properties as determined by the composition of the polymer chain.
Polyethylene:
Polyethylene (PE) is a low cost, translucent thermoplastic polyolefin material that offers great versatility that spans across food, medical, cosmetics, automotive and construction applications for its high impact strength and puncture resistance at temperatures as low as -40C. There are three main grades of PE: high density polyethylene (HDPE), low density polyethylene (LDPE) and linear low density polyethylene (LLDPE). The various grades of polyethylene can be strategically included in package designs in both the substrate and sealing elements. HDPE is easy to process as a substrate and provides excellent moisture barrier and chemical resistance, while LDPE and LLDPE can be used in a multi-layer coextruded structure as a tie/sealing or bonding layer.
Enhanced Barrier PP & PE Materials:
Polyolefins are some of the most widely used materials in packaging applications (rigid and flexible) for their low cost, excellent moisture barrier, ease of processing and recycability. As the global demand for packaging solutions with improved sustainability and recyclability continues to take precedent, mono-material packaging structures have emerged as the solution made possible through major advancements in material science. Polyethylene and polypropylene are the most versatile materials used in the industry today, and plans for additional production capacity in the US alone will add nearly 4Bn Lbs. by 2022. Both PE and PP have excellent moisture barrier properties but exhibit poor barrier properties to oxygen and many organic solvents. As a result, currently both PE and PP are widely used either in a coextruded structure or as a substrate to an oxygen barrier laminated material or film such as EVOH for applications that require a high oxygen barrier.
ICPG’s enhanced barrier technology, can now offer a new monomaterial solution for barrier polypropylene structures (both homopolymer and copolymer) with oxygen and moisture barrier enhancement up to 60%, as well as added clarity and low haze compared to traditional polypropylene materials. This material also offers enhanced stiffness to meet or exceed Polystyrene standards for snapability, allowing for replacement of PS in form-fill-seal appplications as well as offer potential downgauging opportunities for existing structures. ICPG’s enhanced barrier HDPE offers oxygen and moisture barrier enhancements up to 40% compared to traditional polyethylene grades.
Generally, multilayer structures are made using a complex and expensive technology and the final product is not recyclable due to the use of multiple materials (application dependent). However, with a monomaterial structure, packaging solutions are 100% recyclable and can be integrated back in the structures to create a closed loop system.
For more information on ICPG's revolutionary XPP Enhanced Barrier Polypropylene download your own copy of our product sheet today:
