Common Problems and Solutions When Packing Multi-Wall Paper and Poly Valve Bags
A Pasted Valve Stepped End (“PVSE”) bag, is a common industrial packaging style designed to package a wide variety of dry flowable products. Valve..
October 6, 2020
This post was updated on July 8, 2022.
For decades multi-wall paper bags have been constructed from three or more plies of traditional natural kraft paper. However, modern sack kraft paper is now so strong that 3-ply bags are seldom necessary. Two-ply bags made from high-performance, extensible paper can easily hold up to 100lbs of material. Plus, it fills faster and provides a more environmentally sustainable package. Few paper plies yield such significantly reduced paper bag cost.
First, let’s review the characteristics of each type of sack kraft paper:
Traditional Kraft Paper |
High-Performance Extensible Paper |
Manufactured from short wood fiber |
Manufactured from long wood fiber |
Heavy, coarse sheet |
Smooth sheet |
Strength through high basis weight |
Strength through superior stretch and flexibility |
Limited stretch |
6-7% stretch |
Low levels of porosity |
High levels of porosity |
Limited energy absorption |
Superior energy absorption |
Ideal for 3-4 ply bag construction |
Ideal for 2 ply bag construction |
Kraft Paper is a paper material made entirely from wood pulp and produced by a modified sulfate pulping process. The paper is coarse and noted for its strength. The name is obtained from the German word “kraft” meaning strength. Its natural color is brown, but by using semi-bleached or bleached sulphate pulp it can produce lighter shades including white.
Extensible Paper is made from long, slender, flexible cellulose fibers. The paper is smooth and noted for its stretch. Extensible paper is produced mechanically by compressing a paper web between a rubber blanket and a drying roller. The process produces a paper with a built-in stretch, which produces greater strength and permits fewer paper plies in a bag.
Transitioning from 3-ply natural kraft to 2-ply extensible paper reduces the raw material in the package by a full paper layer. Thus, substantial cost savings may be achieved when selecting this packaging method. The reduction of raw paper material in the bag brings the following advantages:
Bags constructed with fewer plies significantly reduces the amount of paper required to produce a finished bag. This, in turn, limits the ecological impact on our forests. Continuous investments in new technology are made to achieve even better energy efficiency and raw material usage.
Two-ply bags allow a customer to receive up to 30% more bags per truckload/container. The increase in the number of bags per load reduces the inbound freight cost per bag substantially. Furthermore, fewer freight movements reduce our overall carbon footprint.
Brown and bleached (white) extensible sack kraft paper grades offer excellent strength properties. The strongest grades have a TEA index of up to 3.8 J/g. These grades are ideal for 2-ply industrial bags with a filling weight of up to 110lbs (50kg).
For fast and dust-free cement filling or other powdered goods, we offer papers with a perfect combination of strength and porosity. These papers are strong enough to withstand tough demands, yet they are porous enough to allow for efficient deaeration.
In particular, sack kraft paper grades have excellent print quality, resulting in a high-quality print result that enhances your bag's point-of-purchase appearance.
A Pasted Valve Stepped End (“PVSE”) is a common industrial packaging style for dry, flowable products. The bag is packed on equipment that fills it from a horizontal spout. When the bag is discharged from the packing equipment, the product inside the bag self-seals the valve opening.
Two-ply valve bags are one of the most common industrial bag styles in use today with much of the world’s cement, minerals, and resins packed in them
A SOM bag is an open mouth bag that is closed using sewing thread. The bag has a flush-cut tube that is factory closed at one end and left open at the other end for the customer to pack and sew closed. This bag style can be gusseted or made with a flat tube.
SOM bags are typically manufactured in 3-ply natural kraft paper. However, 2-ply extensible paper SOM bags are growing in popularity due to their strength and cost-effectiveness.
PBOM bags are ideal for products that need a barrier liner to preserve them, like in the chemicals, food, pharmaceutical, and pet food industries. PBOM bags can be closed by sewing, but they are most often closed/sealed by Pinch Bag Closers (PBC) using a pre-applied hot-melt to create sift proof closures.
PBOM are typically manufactured in 3-ply natural kraft paper. However, 2-ply extensible paper PBOM bags are capable of being produced and offer similar strength and cost benefits.
An SOS bag is a block bottom, gusseted style bag that is capable of standing up unsupported due to its flat, machine-formed base. SOS bags provide superior stability during filling. Also, their shape stacks well and creates a stable pallet load.
Two-ply extensible paper SOS bags are commonly used for retail goods such as charcoal and pinion wood.
Our multi-wall paper bags are produced with state-of-the-art converting equipment in plants located domestically and abroad. Available in traditional kraft or high-performance extensible paper, Southern Packaging offers a wide variety of bag styles to suit all your multi-wall paper packaging needs.
As one of the premier bulk packaging distributors in the country, we have succeeded by listening to our customers, identifying their needs, and delivering on our promises.
Strategically located near Dallas, Texas, our company buys, sells, and delivers more than 1,100 different industrial packaging products to nearly 900 locations across the U.S.
Our substantial inventory includes all styles of FIBCs, paper bags, UN-certified bags, BRC & AIB food quality bags, polybags, BOPP bags, dunnage bags, and bulk shipping supplies.
If you are interested in any of our products, please contact us today!