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Paper bag

technology Maturity 7-9 Next article →

A paper bag is a versatile container used for transporting a vast array of products.

Nordic Climate Solutions 2009-09-09
Nordic Climate Solutions 2009-09-09

Most common versions are made from kraft paper, which is a strong and soft material. These bags serve many roles, from simple shopping carriers for groceries to heavy-duty industrial sacks. They can hold delicate items like electronics or clothing, and even heavy materials like cement or flour. Because they are primarily made from wood fibers, paper bags biodegrade easily. This makes them a different ecological choice compared to plastic bags.

India - Varanasi paper bag maker - 0078
India - Varanasi paper bag maker - 0078

Industrial paper sacks are manufactured through a highly organized, automatic process. This production involves two main stages: tube forming and bottom folding. First, a machine called a tuber takes the kraft paper and forms it into a continuous tube. During this stage, glue is applied at a cross-pasting unit to join the layers together. If the bag requires extra protection, a thin film may be perforated and combined with the paper. A perforating knife then cuts this long tube into individual segments. These segments move to a machine called a bottomer to complete the bag.

Bolsas de cemento Loma Negra 02
Bolsas de cemento Loma Negra 02

There are two primary designs for these industrial sacks based on how they are filled. The first type is the open-mouth bag, which is a tube of paper layers with a sealed bottom. These bags are filled through the open top and then closed using adhesive, tape, or stitching. The second type is the valve bag, which is sealed at both ends. These bags are filled through a specific valve, a design commonly seen in cement sacks. Some sacks are also multi-walled, meaning they use several layers of paper for extra strength. These layers provide high tear resistance and elasticity to protect the contents.

Two paper bags
Two paper bags

To make kraft paper, manufacturers use wood pulp extracted from softwood trees. The long fibers in softwood are essential because they provide the paper with its strength. During production, the paper undergoes a process called microcrepping. This involves drying the paper with loose draws to allow the fibers to shrink. This shrinkage causes the paper to elongate, which improves its elasticity and toughness. Some bags are also laminated with polyethylene, a type of plastic. This coating creates a barrier that protects the contents from moisture, grease, and bacteria.

Sugar, Downpatrick, September 2010
Sugar, Downpatrick, September 2010

The history of the paper bag is marked by several key inventions in the 19th century. In 1852, a Pennsylvania schoolteacher named Francis Wolle invented the first machine for mass production. He and his brother later founded the Union Paper Bag Company. In 1853, English papermaker James Baldwin patented an apparatus for making square-bottomed bags. Later, in 1871, Margaret E. Knight designed a machine that created flat-bottomed bags. These were more efficient than the older envelope-style designs. In 1883, Charles Stilwell patented a machine for square-bottom bags with pleated sides. These were known as "Self-Opening Sacks" because they were easy to store and use.

01 Jedes Josera-Krümel ist kostbar...
01 Jedes Josera-Krümel ist kostbar...

Innovation continued into the 20th century with improvements in strength and handles. In 1912, a grocer named Walter Deubener began using cord to add handles to paper bags. These "Deubener Shopping Bags" were very strong and could carry up to 34 kg. By 1915, he was selling more than one million of these bags every year. Modern industrial sacks are even more capable, often protecting products weighing up to 50 kg. The strength of these sacks is highly efficient; the weight of the bag to its contents can reach a ratio of 1:250. In 2015, the Paper Bag Co in the UK even set a Guinness World Record by making the world's largest paper shopping bag.

Today, the use of paper bags is closely tied to environmental policy and sustainability. While plastic bags became very popular in the 1970s due to their low cost, many areas are now moving away from them. The European Union has adopted directives to reduce the consumption of single-use plastic bags. This shift has caused paper bags to be re-introduced in many shopping environments. To promote sustainable packaging, the "European Paper Bag Day" was established in 2018. This annual event on October 18 encourages people to reuse and recycle paper carriers. This transition highlights how a simple invention continues to adapt to the needs of the planet.

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🖼️ Images & Media (6)
File:Nordic Climate Solutions 2009-09-09.jpg
Nordic Climate Solutions 2009-09-09.jpg
File:Sugar, Downpatrick, September 2010.JPG
Sugar, Downpatrick, September 2010.JPG
File:India - Varanasi paper bag maker - 0078.jpg
India - Varanasi paper bag maker - 0078.jpg
File:01 Jedes Josera-Krümel ist kostbar....jpg
01 Jedes Josera-Krümel ist kostbar....jpg
File:Bolsas de cemento Loma Negra 02.JPG
Bolsas de cemento Loma Negra 02.JPG
File:Two paper bags.jpg
Two paper bags.jpg
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