What is the process of making paper bags?

08 Apr.,2024

 

‍Brown paper bags are a packaging essential but how are they made in 2022 and are they really eco-friendly? 

Paper bags have been a shopping staple for centuries. Brown paper bags, white paper bags, paper bags with handles or without, there are multiple different types of paper bags that have become part of our daily lives without us even realising. 

Have you ever thought about how a paper bag is made though? Or when they first came into use? We’ve put together this guide on how paper bags are made in 2022 to answer exactly that.

When was the paper bag invented?

Paper bags have become everyday packaging staples but you might be surprised to learn just how long they have been around. The first paper bag was invented back in the 1800’s in the United States. While the very first brown paper bag appeared in the 1870’s, it was actually in the 1850’s that a US school teacher, Francis Wolle, invented the first machine to create paper bags. 

Following his invention Wolle and his brother went on to found Union Paper Bag Machine Company alongside a paper packaging plant in 1869 that was capable of producing 1000 feet of paper in one minute. That very paper packaging plant is still in operation today! Whilst it was Wolle who invented the machine to actually make a paper bag, the iconic square-bottomed paper bag design that we’ve become accustomed to was the work of Luther Childs Crowell in the 1870’s. 

Who would have thought that the humble brown paper bag would still be such an essential over 150 years later?!

How are paper bags manufactured?

Whilst the process of making paper bags today has advanced from Wolle’s original designs, the principle remains largely the same. Paper bags are made on large machines and for every 1 paper bag produced, 1 gallon of water is required. The process of manufacturing a paper bag starts with paper pulp, which is essentially thin shavings of wood from trees.

The paper pulp comes from trees that have been dried for at least three years. The dried tree bark is stripped, cut into 1-inch strips and then cooked into pulp using intense pressure and heat.

The paper pulp is then pressed into flat sheets or rolls of paper. These sheets and rolls will be cut to size (usually twice the required height of the finished paper bag) and then folded over. The two parallel open sides will be glued together either by pressing the glued sides together or via heating and pressing. Once complete you’ll have a simple flat paper bag (like the kind you might get from a sweet shop). If you want to make a more complex design, such as a flat-bottomed bag, you follow the same process but simply include more complex folds along the bottom of the bag in order for the finished paper bag to stand up. Paper bag handles are made separately and affixed with glue.

What are paper bags made out of?

You might think you already know the answer to this question, paper bags are made of paper, right? 

Well, technically yes but depending on the style, design and use of the bag, there are various different types of paper that can be used. Standard brown paper bags are made using kraft paper which can come in any colour (creating coloured paper bags). You can also create paper bags using laminated kraft paper. This creates bags that have a plastic coating on the inside to prevent moisture from soaking through the paper, a particularly good idea for food packaging. 

Paper bags made using kraft paper can be any colour, not just brown, and any weight. Typically brown paper bags will be made using 60gsm paper and can come in a wide variety of sizes. As we become more eco-conscious, paper bags can also be made using recycled kraft paper, usually using strong 110gsm kraft paper, for an environmentally-friendly packaging solution.  Nowadays paper bags tend to be created using a combination of raw and recycled paper. 

How are paper bags disposed of?

The great thing about paper bags is that disposing of them is quick, easy and most-importantly, environmentally friendly. 

There are three key ways to dispose of paper bags:

  • Recycling
  • Composting
  • Reusing 

As they are made of paper, paper bags can be recycled so that the paper can be used again, usually in the form of another paper bag. 

In order to recycle a standard paper bag, the paper will be shredded, boiled and turned back into paper pulp. This will then be rolled out into new sheets of paper and the manufacturing process begins again. If you want to dispose of your paper bags yourself then one of the main ways you can do so is via composting. Once you’ve set up your compost bin with garden waste and compostable waste (e.g. kitchen scraps) you can begin adding materials such as paper. And of course, you don’t always have to dispose of paper bags right away. Providing they haven’t ripped or been damaged, you can reuse paper bags multiple times before recycling or composting them.

If you opt to reuse your paper bags then you don’t just have to reuse them in their original form. Whilst you can continue to use them as a packaging source until they are no longer usable, you can also use the paper for protecting delicate packages and lining household items such as pet trays. 

Are paper bags biodegradable?

Generally speaking, paper bags are biodegradable, hence why they’re a great choice for composting as mentioned above.

Thanks to how the paper pulp used to create paper bags is made, from wood chips, the final kraft paper is just cellulose fibres that can be easily decomposed through bacteria when added to compost bins.

In order for a paper bag to be fully biodegradable it needs to be free from ink, plastic coatings and other toxins and contaminators. 

Are paper bags eco friendly?

Paper bags have long been heralded as the eco-friendly packaging option and for good reason. 

The fact that paper bags themselves can be recycled is a big tick for the environment. Whilst the production of paper bags does require trees to be cut down, nowadays most paper bags are manufactured using a mix of recycled and raw materials, resulting in much less impact to our forests. The use of recycled paper in the creation of paper bags also requires less energy, helping to reduce the amount of greenhouse gases the manufacturing plants are emitting. 

Paper bags can also be reused multiple times before being recycled, helping to further boost their eco credentials. Of course nothing is ever perfect and there are certain parts of the paper bag manufacturing process that are harmful to the environment. Using a paper bag however is much more environmentally friendly than a plastic alternative…

Why use paper bags over plastic?

Paper bags can be used for many different purposes including carrying groceries or items you’ve bought when shopping, carrying your packed lunch or even for giving gifts. Not only do they have many uses but in recent years many people have actively decided to use paper bags over plastic alternatives. 

We know that paper bags are considerably more environmentally friendly than plastic ones, but exactly why should you use paper bags over plastic?

  • Paper bags are biodegradable unlike plastic alternatives. Whilst plastic bags will sit on the earth's surface for decades, paper bags will biodegrade and turn into natural fertiliser for plants and trees.
  • Paper bags don’t fill up the oceans. As plastic bags are disposed of they will often make their way into our oceans and sea beds. Plastic bags in the oceans can cause an array of problems such as choking animals and contaminating the water and beds.
  • Paper bags are non-toxic. One of the biggest issues with plastic bags is that they are made from toxic waste producing fossils. Studies have shown that certain types of plastic and plastic bags can leak harmful chemicals. 
  • Paper bags are almost completely emission-free. Since paper bags are mainly made using recycled paper nowadays, the process of creating them uses less transportation which in turn means less emissions. 

Where can I buy brown paper bags?

After hearing how paper bags are made and how good they are for the environment, we wouldn’t be surprised if you want to buy some of your own. 

As we all look to take steps to becoming more sustainable and eco-conscious, it's no surprise that more and more people are looking for paper bags. Well luckily for you, paper bags are readily available for purchase, including right here from Bestpac. At Bestpac we produce the highest-quality paper bags and sleeves for bakery and patisserie use. 

Biodegradable, sustainable and recyclable, you can be assured that our paper bags use only the highest quality materials and manufacturing processes. For more information on our paper bags and finding the right paper packaging solution for you, our experts are always on hand to help. You can contact them here. 

Centuries before, using sacks made of jute, burlap, and jute were the primary methods of holding goods. Although they are sturdy, they are also time-consuming and expensive to produce back in the day. On the other hand, paper bags are portable and much more economical to process.

Kraft paper bags became popular in the 1800s when inventors developed the first technology to mass-produce them. Francis Wolle patented the first paper bag-making machine in 1852. In 1869, Wolle and his brother founded the Union Paper Bag Machine Company with a paper packaging plant that could create 1,000 feet of paper per minute.

Years later, Margaret Knight, a prolific inventor working for the Columbia Paper Bag Company, realized that Wolle’s envelope-like design or today’s pinch-bottom paper bag is not practical and efficient. So she created the square-bottomed packaging and built a machine that paved the way for the widespread commercialization of paper bags.

Since then, paper bags have been a market mainstay. But unlike before, technology has helped producers manufacture paper bags faster and with less waste and cost. Here are how commercial paper bags are processed today.

Preparation of Raw Material

Wood that a pulp mill receives can come in a variety of shapes and sizes. It could come in the form of round-wood bolts (short logs) with the bark still attached or as half-dollar-sized chips from a debarked round wood.

If manufacturers use round wood, a debarking process would be necessary. This is commonly done by tumbling the wood in huge steel drums with wash water. And if the pulping process requires chemical digestion, the debarked wood bolts are processed in a chipper. After that, the chips are sized, cleaned, and stored in preparation for further processing.

Fiber Separation

Here, the chips are stored in a big pressure cooker (digester) and applied with kraft pulping chemicals. The chips are digested with steam at precise temperatures in order to separate the fibers. This process also partially dissolves lignin and other extractives from the wood. These can weaken and discolor the paper if not removed.

Some digesters constantly run with a steady supply of chips (furnish), while others treat batches at a time. The cooked pulp is discharged into a pressure vessel after the digesting process. The steam and volatile materials are piped away, and the heated pulp is reintroduced into the chemical recovery cycle. Here, the pulp is screened, cleaned, and most of the water is removed in preparation for papermaking.

Bleaching Process

Because raw pulp still contains a significant amount of lignin and other discoloration, it must be bleached to produce white or light-colored papers, so they undergo bleaching. The order in which they are applied is determined by a variety of criteria. This includes the cost of bleaching chemicals, the type of pulp, and the state of the pulp.

This process also further dignifies the fibers through chlorination and oxidation. At the end of the process, the dissolved lignin is extracted from the surface of the fibers using sodium hydroxide.

Papermaking Procedure

The bleached and refined pulp then enters the paper mill and is mixed with water. This pulp solution goes through a series of rotating and stationary blades to make it more refined. The process gives the fibers clean-cut or “fibrillated” ends. Fibrillated fibers bind more tightly with other fibers, making the paper stronger.

Afterward, fillers like calcium carbonate and clay are added to make the paper opaquer and give it better density. To further improve the texture of the paper, manufacturers add dyes and optical brighteners. This final solution enters the paper machine, where the water is squeezed out, and the paper is dried and pressed.

Paper Sheering & Design Printing

The prepared sheets of paper are now stacked one on top of the other before being cut to the customer’s specifications. The shape and design of the paper bag are decided and implemented at this stage.

These papers go through a printing cylinder in a conventional or digital printing press. As it passes through the machine, the client-specified design is stamped into the paper. Typically, the process uses fast-drying solvent or water-based inks to attain quality print at high speed.

Eyelet Punching and Paper Creasing

After the sheering stage, certain details of the customer-specified paper bag handles will be applied to the paper. For example, if the paper bag is going to have rope handles, the material will undergo eyelet punching. The handles are also connected in the same process. If the bag has cut-out holes as handles, that will also be done at this stage.

After that, the paper is pleated to facilitate subsequent folding and sticking of the various sections of the bag. It guarantees that the bags are folded, stuck, and assembled in a consistent manner.

Hard Press

Clients may require their bags to be durable and strong at times. So sheets of paper are pasted together to create a double layer and make the paper bag thicker. After the adhesive is applied between sheets, a machine pushes them together for a clean and long-lasting bond.

Folding, Sticking, and Finishing

The manufacturing process has now reached its conclusion. At this stage, all of the bags’ separately processed pieces, including the front, back, and side flaps, are assembled.

Usually, paper bag manufacturers use a tubing machine. The machine draws in the components, fold them together, and bond them with adhesive. Tuber speed generally runs at 150-250 feet per minute.

In certain procedures, depending on the design, the manufacturer adds another layer of paper for the bottom. This makes the lower part stronger so the paper bag would not easily tear when holding heavy objects.

After that, the application of the finishing touches, such as adding the rope handles, are also completed.

Bagitan Packaging – Your Source of Sustainable Paper Packaging

Bagitan Packaging manufactures professional paper bags, food packaging, and foil packaging for wholesale, retail, and redistribution. Our customizable packaging is sourced from 100% recyclable materials, making it suitable for brands that endeavor to deliver sustainable packaging to their customers. We handle bulk long-term supply and ship all over the world.

Visit our website at bagitanpackaging.com to learn more, or contact us at [email protected] to discuss your packaging needs.

What is the process of making paper bags?

How are Paper Bags Made? (Infographic)