Packaging Technology and Engineering. Dipak Kumar Sarker
this can involve shipments back and forth across the globe. This process is undertaken by collecting the products together (e.g. a paperboard box holding blister trays of pharmaceutical pills or a corrugated cardboard box holding plastic laminated cartons of milk). Tertiary packaging is occasionally referred to as transport packaging and is needed to make convenient bundles of secondary packaged goods for mass transport or ultimate delivery of units or secondary packaging; it is used specifically to prevent physical damage that may occur during delivery (e.g. high‐density polyethylene [HDPE] skip or pallet). Recent studies based on damage to all transported foods, estimated at approximately 5–10% of all foods transported, demonstrate the value of primary and secondary packaging [4]. The term ‘unit load’ is often used to represent the packaging group consisting of the compounding together of more than one type of packaging for delivery processes and can be exemplified as the unit repackaged with stretch film on the palette. Consumer packaging is a term used to describe the packaging of a unit that reaches the final consumer from a retail outlet and this represents the received goods that make an impression on the consumer.
Identification of materials, such as plastics, that can be reutilised is an important part of the push for improved recycling. The three types of basic packaging – primary, secondary, and tertiary – encompass virtually all forms of containment (Table 1.1), which often however possess different degrees of reusability. Primary packaging has a role in containing and protecting the commodity directly and is generally based on high‐purity materials; secondary packaging protects the integrity of the primary; and tertiary protects the secondary packaging and permits shipping and transportation of the primary and secondary products within the tertiary packaging. Consequently, secondary and tertiary packaging need lower levels of material purity and, therefore, may be more open to incorporation of recycled material. Occasionally, primary and secondary packaging are combined but they may also not have the same physical presence, for example shrink‐wrap (secondary) covering of a carton (primary); this is often used when the product cannot be easily corrupted by the carton. Primary packaging may be something like a sachet, a bottle, or a blister, which are often not accessible to current recycling practices. Secondary packaging is typified by a carton or a box and tertiary packaging is typified by a carton with an outer wrap. Tertiary packaging is typically a skip, drum, crate, etc. and represents containers that can make use of mixed aggregated recycled materials. The risk of primary packaging lies in its intimate contact with the product, which could be seen as a risk of product compromise and contamination. Typically this could involve the increasing loading of plasticiser or toxic materials in product contact packaging resulting from recycling. Chemical risk is less important in secondary packaging but significant risk arises from misleading information on the pack that could potentially cause injury to the recipient.
Table 1.1 Packaging: contains, protects, preserves, transports, ‘informs’, and ‘sells’.
| Types of use/function | Risk | Example |
| Primary: protects and directly envelops the drug (pharmacy shelf or home) | Could compromise and contaminate the product | Can, pouch, blister, jar, bottle, or ampoule |
| Secondary: protects the packaging that protects the drug (for warehousing); used to group primary packages together | Misleading information on the pack | Carton or box |
| Tertiary: protects the secondary packaging. Purpose: bulk handling, warehouse storage, and transport shipping. The most common form is a palletised unit load that packs tightly into shipping/haulage containers | Pallet, hopper, skip, or over‐wrap |
The international identity code (Table 1.2) ascribed to the recycling of materials used was devised in combination by the bodies concerned with packaging use but fell under the remit of the American Society for the Testing of Materials (ASTM), which encompasses the International Resin Identification Code (RIC); the American National Standards Institute; and the European Commission (based on decision 97/127/EC – ID System for Packaging Materials, which is underpinned by council directive 94/62/EC). These bodies and nomenclature systems together have helped group materials into six usable categories (Table 1.2). The categories of plastics, paper, metals, glass, and the seldom used category ‘organic materials’ in addition to composite materials are now marked on most products to aid recycling and clarify chemical make‐up. The codes range from 01 for PET plastic, 22 for paper, 41 for aluminium, and 79 for glass through to 80 and higher numbers for composite or mixed materials. The table also indicates the main uses of the listed material, which includes, for example, in the case of iron (number 40), its use in aerosol cans, tin‐plated cans, lids, and staples but that might also include fittings and hinges in wooden crates. Indexed labelling of packaging materials in this manner has been hugely valuable and is responsible for much of the improvement in worldwide recycling and local municipality recycling practice.
1.2.2 Types of Packaging: An Overview and the Basics
The primary types of packaging are tinplate, aluminium, plastics, paper and paperboard, glass, and biopolymers but can also extend to wood and wicker or ‘raffia’ materials. The robustness and purity along with costs associated with transport and shipping have a large bearing on selection. Shipping costs are by no means trivial as there is an additional carbon footprint associated with the pollution caused by freighting goods around the globe in addition to the direct paid costs. Division of packaging materials is often performed on a convenient chemical basis; for example, organic and inorganic, natural and artificial/synthetic, porous and solid, or wettable and water repellent. Other suitable classifications might include flexible and rigid, degradable and non‐degradable, or recyclable and non‐recyclable. Yet other relevant definitions could also include the malleability or ductility or the thermoforming and thermosetting formulation. In reality, most packaging materials fit into a number of categories and so the classification is by no means straightforward. For example, paper is generally porous, malleable, wettable, and both natural and artificial in terms of its processing history. A representation of the complexity involved in any classification and the diversity of firms or organisations, material, size, and content is given by the vessels shown in Figure 1.1. Packaging used for pharmaceuticals [5,6], foods [7], and devices has different requirements and yet fulfils the identical overall goal.
Table 1.2 Accepted international identity and recycling codes from the American Society for the Testing of Materials D7611 International Resin Identification Coding system, the recycling symbols of the American National Standards Institute, and the European Commission/Union identification of packaging materials for recycling (94/62/EC and 2008/98/EC).
| Category | Numerical code | Abbreviation code | Packaging materials(s) | Use |
| Plastics | 01 | PET, PETE | Polyethylene terephthalate | Drinks bottles, trays, fibres |
| 02 | HDPE | High‐density polyethylene | Tough bottles, bags | |
| 03 | PVC, V |