With numerous options to choose from, how can brand owners and converters identify the perfect packaging material that satisfies the processing, performance, and business needs for their food products? In this blog series, we'll explore the features of widely-used rigid plastic food packaging materials, assessing both the benefits and drawbacks of a common option, Polyethylene (PE). Keep reading to discover 6 essential attributes of PE packaging material to consider when choosing a rigid plastic food packaging material for your upcoming project.
PE is derived from the polymerization of ethylene which produces very long, straight chains of hydrocarbon monomers. Adjustments in the polymerization process allow for variations in branching, producing different grades of polyethylene packaging material with unique characteristics:
Polyethylene is the most widely used commodity plastic and is mass-produced for a vast range of applications. In rigid packaging, PE is the second most used material behind PET, accounting for 26.1% of consumption in 2023 according to the Smithers report “The Future of Rigid Plastic Packaging to 2028.”
In 2023, the global demand for PE in rigid plastic packaging is expected to hit 17.4 million tons. Moreover, this demand is set to grow at a compound annual growth rate (CAGR) of 2.3% from 2023 to 2028, reaching 19.5 million tons.
The various grades of PE available in the market make this a highly adaptable material choice for a range of applications in various end-use markets ranging from food & healthcare, consumer products, electronics, and agriculture and can be used in a variety of packaging processes. For example, while HDPE is commonly used for applications like jugs and bottles, LDPE or LLDPE is often used for flexible packaging like wrapping, tubing & bags. Blow molding is the most prevalent processing method for PE in the rigid plastic packaging market, followed by injection molding, and thermoformed packaging to a more limited extent.
The adaptable nature of polyethylene packaging material means that it satisfies a range of performance requirements for packaging applications across end-use market sectors. For example, the use of PE is common in the food packaging industry to safeguard products ranging from fresh fruits & vegetables to frozen items & liquids, because of its moisture resistance and ability to preserve freshness. The healthcare sector relies on the hygienic and protective nature of PE, and its resistance to contamination, while among the consumer goods, this material provides a lightweight, sturdy and economical method to safeguard products, and provide the necessary chemical resistance to packaging products such as laundry detergents.
The properties of polyethylene packaging material depend strongly on type, and the molecular weight, crosslinking, and presence of commoners all strongly affect its properties. In general, polyethylene materials have excellent chemical and impact resistance, good electrical properties, and a low coefficient of friction but vary among commercially available grades:
HDPE & LDPE grades of Polyethylene are considered food-safe materials and there are FDA-approved resins of each grade available for food contact applications. These materials have excellent chemical resistance properties, which means that the materials do not react or degrade when they come in contact with food products or leach harmful chemicals into foods when stored at a variety of temperatures. In addition, HDPE provides moisture barrier properties which prevents the permeation of moisture through the plastic, keeping the product safe from oxidation and spoilage.
One significant benefit of using polyethylene packaging material is its recyclability. As concerns about plastic waste continue to rise, many organizations are working to develop practical guidelines and standards for creating recyclable packaging. These guidelines are intended for use by packaging manufacturers and brand owners to ensure their packaging aligns with industry-wide sustainability goals and targets, as well as evolving legislation.
To be considered recyclable, a material must be accessible to at least 60% of consumers through recycling programs that collect it for recycling. Furthermore, there must be a viable market for the recycled material, and it must be capable of being accurately sorted and processed at a material recovery facility.
With various grades and formats (i.e., flexible vs rigid) of PE plastic, recyclability of this material in the US is limited to two grades of PE plastic – rigid HDPE & flexible LDPE.
Rigid HDPE (RIC #2) has been classified as APR Design Preferred in a “natural” or uncolored. Colored HDPE is not considered recyclable by APR and Natural HDPE is separated from Colored HDPE using NIR color sortation technology. Rigid, natural HDPE is also and is considered "Widely Recyclable" by How2Recycle, indicating at least 60% of the population has access to Rigid HDPE Recycling programs and can be recycled at-scale.
Because LDPE (RIC #4) is often produced as a flexible film, as well as a rigid packaging, the recyclability of this material is different depending on the packaging format. Rigid LDPE is not considered recyclable per APR design guidelines, and was downgraded to “Check Locally” by How2Recycle in January, 2020, meaning that between 20-60% of the population has access to recycling programs that accept rigid LDPE.
Flexible PE film structures, used in applications including bags, wraps pouches, envelopes, sachets, removable lidding/liners and wraps can comprise of a mix of materials including LDPE, LLDPE, and HDPE. These materials are recyclable through store drop-off collection methods only including grocery stores and other retail locations. Additional components added to the material including colorants, closures and barrier additives must be evaluated using the APR design guide to determine if their inclusion is considered detrimental to recycling.
The versatility, sustainability, and food safety of polyethylene packaging material make it a leading choice across industries. With various grades like HDPE, LDPE, and LLDPE, brand owners and converters can select the most suitable polyethylene to meet both regulatory requirements and consumer expectations for performance and recyclability. As polyethylene packaging material continues to adapt to market demands, it remains a cornerstone in rigid plastic packaging solutions.