Introduction

This guide looks to simplify this process and offer an overview of the most common materials used in flexible packaging. It will look to compare the materials against different criteria in order to suggest when each is best used. This can provide a good starting point for those who are unfamiliar with flexible packaging and plays a valuable role in refining options for customers and Columbus' sales representatives when sourcing packaging. These materials range from plastic materials such as PP or PET, to paper and metal foils. Prices of these materials can vary greatly, and generally higher prices reflect higher barrier properties. This does not mean that the highest-priced material is always the best option, so selections should be carefully considered. An example of this would be that it is not necessary to use a foil material to package a product, which is packed in a stable environment such as a stationary cupboard. In this case, a metallized plastic may offer a more cost-effective solution with similar barrier properties.

Flexible packaging has become consumers' most popular choice for their packaging needs. This is unsurprising considering the advantages this packaging offers, such as cost-effective production and transportation due to lightweight. It also offers consumer conveniences and provides easy openings. Understanding the materials and the options available can be difficult. Manufacturers and end users alike are often unsure as to which material is the best for their packaging needs. There are a number of considerations which a customer needs to take into account when selecting the material for their packaging order. These include the appearance of the product and marketing schemes, the environment that the packaging will be in, and the barrier properties of different materials.

Factors to Consider

  1. Relative Pack/product Cost: Save for products having a high utility relative to their packaging, this will generally indicate the extent to which you wish to minimize material usage, production and pack filling costs. In essence, the higher the cost, the more focus should be given to pack cost reduction. This will be the relative cost of different packaging options in producing a unit each of packed product, without taking into account pack performance or production logistics. In many cases pack cost saving can be more simply achieved by reducing the pack size, and making no change to the materials.
  2. Shelf Appeal: For new products trying to capture market share, or in highly competitive markets, a pack with high shelf impact may be a critical factor to its overall success. High shelf appeal may be linked to pack to brand associations e.g. high quality product with high quality packaging, or a consumer inference of product quality from the image of the pack. This can considerably raise the relative importance of packaging performance and pack product image or message durability.
  3. Pack Performance: This is a broad ranging consideration of the actual pack functionality during its service, the extent to which the pack protects and contains the product. The relative importance will depend on the nature of the product, and the required level of performance. e.g. product containment is critical for liquids which could spoil other products in the consumers shopping basket, and enhanced product protection is important for easily damaged goods.

When choosing packaging materials, there are numerous factors to consider. Each factor should be weighed against the others, in terms of its relative importance. This section is designed to help guide decisions by considering an overall ranking of the relative importance of each of these factors.

Types of Flexible Packaging Materials

One of the keys to understanding flexible packaging materials is to know that it is made up of various types of substrates. This is known as the "structure" of the material. The structure is usually a lamination of various films and in some cases combinations of foil, paper, etc. The choice of structure depends on the form of the product being packaged. Is it a liquid, solid, or powder? Does it contain an oil with a strong aroma? Is it for single or repeated use? What is the shelf life? Will it be stored in the home or at a business location? These questions will help to rule out the types of materials that will not work and eventually lead to the best choice. Table 1 is a quick summary of information provided on various materials. This is a useful tool if one has some knowledge of packaging materials, but it is always best to start from the beginning to develop a full understanding. Coming back to this table will help to make final decisions between material choices.

Comparison of Materials

B. Polyethylene (PE)

PE is actually a range of materials each with different characteristics and uses. Broadly speaking it has the following properties:

- Resistant to chemicals

- Good fatigue strength

- Good for squeezy tubes

- Soft and low strength

- Generally suitable for low temperature use

- Good gas barrier only at thickness greater than 30 microns.

Both PET and BoPET are cost effective materials for short shelf-life products and are suitable for beverage, food, and other consumer products. BoPET is often used for sparkling beverages due to the superior gas barrier properties.

Biaxially Oriented PET (BoPET)

- Excellent gas barrier

- Excellent chemical resistance

- Good thermal stability

- Good strength

- Excellent clarity

- Used mostly for transparent high barrier films

A. Polyethylene Terephthalate (PET)

- Fair gas barrier properties

- Fair chemical resistance

- Good stability

- Crystallizable, better for heat sealing

- Good clarity

- Used mostly for clear container applications

Conclusion

As a result of the new structure quality, it is also intended that this would further promote the advantages of flexible packaging throughout the industry as it continues to grow and take market share away from other packaging formats. Flexible packaging provides a sustainable solution to meet the demands of consumers, reduce costs in the supply chain, and improve package quality. This guideline is a great reference tool for education to those that are new in the industry, and with the ability to get traceable results using the test methods, it provides a targeted approach to training on packaging material and its performance. A better understanding of material performance and specifications will pay dividends at every level in the supply chain. Consumer and retail brand owners will have a better packaging solution, and with an increase in knowledge of material performance, it will be easier for a converter to sell a value-add solution to improve package quality and cost.

One final thought to keep in mind when it comes to specifications. They are both a vehicle to bring new business and a weapon to beat up an existing supplier. It is always easy to complain about quality issues and make changes to a specification, but to truly improve package quality and get the most cost-effective structure, be sure to work closely with the supplier. Specifications can also be very restrictive and costly if there is only one supplier that can meet the requirements.

Always be sure to analyze the cost vs. the performance benefit with any change to a specification and consult with a supplier to see if there are alternative methods or materials that can achieve a similar end result. Specifications should always be reviewed and revised to keep up with changing market conditions and new packaging materials and methods. With successful utilization of the test methods and specification example within this guideline, it is intended that this will serve as a comprehensive resource for converters and end users to upgrade existing structures or develop new ones to improve package quality, decrease costs, and provide a more sustainable solution.

This paper has been legally documented by the Flexible Packaging Association. It is intended to provide a performance-based guideline specification that can be universally used for packaging structure. The test methods have been written to assure they can be done in most laboratories with accuracy. Whether it is used for buying or packaging conversion, it has been structured to allow the user to make informed decisions.