Multi-wall paper bags are an industry standard for shipping dry goods like flour, sugar, animal feed, and more. Every type of business, from local bakeries to large agriculture companies, uses them.
But what exactly goes into making one of these versatile bags? Let’s take a closer look to understand the anatomy of a multi-wall paper bag.
Wall Liners
Multi-wall paper bags are typically three to four plies thick but can have as few as two plies. The plies are “numbered,” starting with the inside ply. If required, the first- or second-position ply typically serves as the plastic moisture barrier. Otherwise, all paper plies are typically between 40- and 60-weight paper, with the first plies being natural kraft and the outside ply being either natural kraft or white paper.
Some industries will use high-performance or extensible paper to help with durability. This paper is often seen in the seed industry or used for exporting goods.
Most Common Types of Multi-Wall Paper Bags
Sewn Open Mouth (SOM)
SOM is the most common style used for animal feed, seeds, and other non-food industries. It’s very quick and easy to make by manufacturers and is usually readily available to customers. The manufactured end is sewn with crepe tape and an EZ Open pull tab, leaving the open end for the customer to fill and sew closed with either a handheld or automated bag sewing machine.
Pinch Bottom Open Mouth (PBOM)
PBOM is a step above SOM, commonly used in the food industries due to increased sealing and air tightness. Bag ends fold over and are heat sealed with a hot melt adhesive that’s pre-applied by the manufacturer. Heat seals typically provide maximum protection against oxygen, moisture, and product leakage.
Pasted Valve Stepped End (PVSE)
This is a specialty bag that doesn’t require a sewing machine or heat sealer. Typically filled with fine powders such as ready-mix and cement, this bag is often used on high-volume packaging lines.
This bag is pre-sealed except for a valve on one end that’s rapidly filled through a tube. Once filled, the valve closes until the end user is ready to open it. Due to the specialty nature and demand, it can only be made by a handful of manufacturers in large quantities, causing extended production delays.
Multi-wall paper bags are essential to many industries, from food production to dry goods. Their construction is fairly simple, but their versatility makes them an indispensable tool in many businesses. Understanding the anatomy of a multi-wall paper bag can help you choose the right type of bag for your particular needs.
S & K Packaging can help you find the perfect industrial paper sacks for your business. We have a wide variety of stock bags available and can custom manufacture a bag to meet your specific requirements. Contact us today to learn more about our products and services.
