How to enhance the strength of carton to meet the needs of users

With the ever-increasing circulation of commodities in the market, the phenomenon of tight storage capacity has become increasingly prominent. In order to ease the space of the storage capacity, the stacking height is increased.

The vast majority of all packaging products are shipped in corrugated boxes, which shows that the corrugated board transport box plays an important role in ensuring the safety of the product from the factory to the customer. The number of stacking layers in storage and transportation is increased. Compressive strength requirements will be higher and higher, if the underlying carton is collapsed, it will cause serious losses. According to estimates of the food industry, about 20% of the products that are damaged each year are caused by packaging problems. Therefore, improving the compressive strength of cartons has become a common requirement for a large number of users.

In the past, the method of increasing the compressive strength of the carton was generally to increase the fiber, or use a thicker backing paper and core paper, or use a multi-layer structure. However, these methods have increased the economic expenditure. Not only the cost of box making has been increased, but also the weight of boxes has increased, and they have taken up more space in transportation and storage, which also increases transportation costs.

With the advent of high-performance corrugated cardboard, carton suppliers have experimented with various methods that can both create reinforced cartons and reduce the paper layers required for box making. These methods can increase the strength of cartons.

Cross-linking - changing fiber direction

Cross-linking is a process that changes the direction of the fibers during the papermaking process. Normally, the paper fibers run parallel to the longitudinal direction. After the box is formed, the fibers are horizontally around the box. This is the worst direction for the carton to resist pressure. Cross-linking causes many fibers to be oriented at 90 degrees to the machine direction. The processing result is that many fibers run vertically up and down the edge of the box, which increases the stacking strength of the carton without adding fibers.

Measuring the strength of a backing paper when cross-linked is to measure its ability to withstand ring-pressure failure. Turn a 6-inch-long, 6-inch-long cardboard strip into a ring to compress it. The number of pounds needed to break it is the material's crush strength. High-compression-strength liners and high-compression-strength core papers not only increase the compressive strength of the vertical edge of the dice cartons, but also increase the compressive strength of the entire cartons.

High pressure - tightly packed cardboard

The high-pressure board forming method is also a method of enhancing the strength of the board during the papermaking process. That is, the paperboard is tightly compressed by expanding the pressure point on the paper fibers. The tighter the cardboard structure, the greater the strength. High pressure paperboard forming also helps to squeeze more moisture out of the pulp, but the key is to make a tighter paperboard and increase its compressive strength.

Additives - Improve fiber adhesion

In this method, various chemical crystals are added to the fibers before and after the papermaking to increase the binding force of the fibers and thereby increase the compressive strength of the corrugated boxes. These additives include, for example, corn, starch, gums, binders and heavy metals, and plastics and urea (formaldehyde) resins. In some cases, fibrous cardboard is also reinforced by chemical spraying the outer layer of the carton.

In general, the use of chemical additives is less expensive than cross-linking or other methods, but when they are more expensive to use than when the weight of the bottom and core paper is increased to make a more rigid carton, then they are meaningless. .

Laminated - double core board reinforcement

This method of reinforcing the strength of a corrugated carton is based on the lamination of two or more layers; core paper. The binder can be a simple corn starch binder to produce an ultra-strength core paper sandwiched between cross-linked, press-formed or conventional strength paper.

The single corrugated structure that the double-core corrugated carton maintains serves as a corrugated carton. It weighs about 10% more than a single corrugated carton, but the resulting compressive strength is greatly increased by 10%. The double-core carton also has greater ring pressure strength, and at the same time, it increases the compressive strength of the carton and plays an important role in stacking more than three heights of the pallet.

The latest developments in high-performance corrugated board materials and containers meet the needs of users in various industries, but people still expect that with the development of modern high-tech technologies, the corrugated paper boxes will continue to increase their compressive strength so as to reduce the risk of packaging in the circulation of goods. Damage caused by economic losses.

(author/zhangxin)

China Packaging News