Читать книгу Packaging Technology and Engineering - Dipak Kumar Sarker - Страница 21

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	Polyvinyl chloride	Bottles of corrosives
04	LDPE	Low‐density polyethylene	Polythene bags, containers
05	PP	Polypropylene	Shampoo, syringes
06	PS	Polystyrene	Cases, Styrofoam
07	OTHER, O	All other plastics (PC, PA, PAN, SAN, bioplastics)	Bottles, biodegradables
08		Reserved for new materials
09	ABS	Acrylonitrile–butadiene–styrene	Tough coverings, cases
Paper	20	C PAP, PCB	Cardboard	Secondary packaging
21	PAP	Other paper	Leaflets
22	PAP	Paper	Labels
23	PBD	Paperboard	Boxes
Metal	40	FE	Steel (low‐carbon iron)	Aerosol cans, tin‐plated steel, lids, staples
41	ALU	Aluminium	Cans, closures, tubes
Organic material	50	FOR	Wood	Crates, pallets, boxes
51	FOR	Cork	Bottle stoppers
60	COT	Cotton	Insulation
61	TEX	Jute, hemp	Sacks, packing
62–69	TEX	Other textiles
Glass	70	GLS	Mixed glass, multi‐part glass	Glass bottles, food, medicines
71	GLS	Clear glass
72	GLS	Green (chrome oxide) glass
73	GLS	Dark sort glass
74	GLS	Light sort glass
77–79	GLS	Metal‐backed glass (Cu, Ag, Au, respectively)
Composites	81	Ca)	Mixed media: paper/plastic	Chilled grocery, drinks cartons
82	Ca)	Paper and fibreboard with aluminium	Pack liners
90–92	Ca)	Plastic and metals	Retortable pouches
95–98	Ca)	Glass and metals	Reinforced glass
99	Ca)	Other

a) LDPE, LD polyethylene; PA, polyamide; PAN, polyacrylonitrile; PAP, paper; PC, polycarbonate; PET, polyethylene terephthalate; SAN, styrene–acrylonitrile.

Numerical and abbreviation codes are also shown in Figure 8.2a(iv).