A paper bag
or paper sack
is a preformed container made of paper
Paper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....
, usually with an opening on one side. It can be one layer of paper or multiple layers of paper and other flexible materials. A bag is used for packaging and/or carrying items.
Paper shopping bag
Shopping bags are medium sized bags, typically around 10-20 litres in volume , that are often used by grocery shoppers to carry home their purchases...
s, brown paper bag, grocery bags, paper bread bag and other light duty bags have a single layer of paper. A variety of constructions and designs are available. Many are printed with the names of stores and brands. Paper bags are not water proof. Types of paper bag are: laminated, twisted, flat tap. The laminated bag, whilst not being totally waterproof has a laminate that protects the outside to some degree
Multiwall paper sacks
Multiwall (or multi-wall) paper sacks or shipping sacks, are often used as shipping container
A shipping container is a container with strength suitable to withstand shipment, storage, and handling. Shipping containers range from large reusable steel boxes used for intermodal shipments to the ubiquitous corrugated boxes...
s for bulk materials as fertilizer, animal feed, sand, dry chemicals, flour and cement. Many have several layers of sack paper
Sack Kraft Paper, or just sack paper is a porous kraft paper with high elasticity and high tear resistance, designed for packaging products with high demands for strength and durability.-Manufacturing:...
s, printed external layer and inner plies. Some paper sacks have polyethyelene foil or polyethylene coated paper
Coated paper is paper which has been coated by a compound to impart certain qualities to the paper, including weight, surface gloss, smoothness or reduced ink absorbency. Kaolinite or calcium carbonate are used to coat paper for high quality printing used in packaging industry and in magazines...
layer in between as water-repellant barrier.
There are two basic design of bags: open mouth bags and valve bags. Open mouth bag is a tube of paper plies with only one bottom end sealed by the paper sack producer. The bag is filled though the open mouth and then closed by stitching, adhesive, or tape. Valve sacks have both bottom ends closed and are filled through a valve. A typical example of valve bag is the cement sacks.
Paper bags are readily recyclable. Plastic or water-resistant coatings or layers make recycling more difficult.
Margaret E. Knight (1838-1914) was an employee in a paper bag factory when she invented a new machine part to make square bottoms for paper bags. Knight can be considered the mother of the grocery bag, she founded the Eastern Paper Bag Company in 1870.
On 20 February, 1872, Luther Crowell also patented a machine that manufactured paper bags.
- Brody, A. L., and Marsh, K, S., "Encyclopedia of Packaging Technology", John Wiley & Sons, 1997, ISBN 0-471-06397-5