Environmental Engineering Reference
In-Depth Information
Paper
Paper is one of the oldest packaging materials in use. Different types of paper and paper
products are used in primary, secondary, and tertiary levels of packaging. According to the
technology used to produce cellulose from wood chips, there are two types of papers: kraft (or
sulfate) and sulfite paper. Kraft is a strong paper used for multiwall bags for dry products such
as flour and sugar. Sulfite paper is generally bleached and weaker than kraft paper and used
for wrappers, bakery bags, and grocery bags.
Paper has poor properties as a moisture barrier or as fats and oils barrier. To improve imper-
meability to water, paper is coated with wax. To improve resistance to fats and oils, cellulose
is further refined than regular paper to get a tighter structure. This type of paper is called
greaseproof
paper, and it has a translucent aspect. A variation of greaseproof paper is glassine
paper, which has a high-gloss finish obtained by finishing rollers. Besides an improvement in
moisture and grease resistance, waxed and greaseproof papers have a higher resistance to air
diffusion than nontreated papers.
Paperboard is a thicker version of paper used for the manufacture of boxes to protect food
products from mechanical damage. When the food is in direct contact with the box, boards are
made from bleached virgin fibers. However, when the box is not in direct contact with the food
product, as in cereal boxes, then board is made with a mixture of virgin and postconsumer
fiber. Laminate paperboard is a sandwich of multiple layers of plastic film, paper, and
aluminum film and is used to make Tetra Pack
®
type of containers used for aseptically
packaged foods.
Corrugated board is composed by flat and fluted paperboard that is assembled as a sand-
wich to increase the overall resistance. It is mainly used for the construction of secondary and
tertiary containers.
Fiberborad is a high-resistance paperboard and can be either solid or corrugated, used for
crates and boxes, but it is more commonly used for drums for the storage of dry ingredients.
Textiles
Textiles are used exclusively for the manufacture of bags and sacks, which are long lasting,
resistant to puncture, reusable, and biodegradable. Two materials are the most common: jute
and cotton. Jute is the raw material for the production of woven jute sacks, which are used for
the shipping of grains and roots. Cotton bags have two main applications: dry products such
as rice, flour, and sugar, and in smoked meat products, which includes sausages, hams, and
bologna.
Another type of textile bags are the “dry mix bags,” which are frequently used for promo-
tional items in culinary stores and gift shops to bag flour, cornbread mix, pancake/waffle mix,
rice, grains, and cake and scone mixes.
Wood
Wood is used at the three levels of packaging. At the primary level, wood is used to make
gourmet food boxes for specialty products such as smoked salmon, jam, tea, coffee, and
cheeses, and boxes to hold jars and bottles containing jams, wines, and oils. Wooden crates are
also used for transportation of fruits and vegetables. At the secondary level, wood is used
mainly to make wooden crates to hold wine bottles for retailing. The largest use of wood as
packaging material comes at the tertiary level, where it is the main construction material for
the manufacture of pallets and crates to hold secondary packages.
