To understand how a wet strength resin fits into the corrugating process, you first need to understand the process. There are a few different components to it, and each one plays a critical role, from the paper to the adhesives to the additives for those adhesives, such as wet strength resins..
How Corrugated Material is Made
The corrugated material begins as two different types of paper, the heavy linerboard, and the thinner fluting medium. The paper is fed into a corrugating machine. Inside the machine, the fluting medium goes through a series of rollers that give it the wavy shape it will have in the finished product.
The fluting medium is glued between two pieces of liner board with a special adhesive to make a corrugated sandwich of sorts. Sometimes there can be multiple layers of liner board and fluted material to make thicker corrugated products. The finished product is cut and stacked by the machine.
Adhesives
The adhesive is an essential component of the corrugating process. Adhesives are often starch-based, and they are often made from sustainable, renewable starches like corn, potato or wheat. These adhesives are usually cured with heat to achieve a better bond and remove moisture. Adhesives need to be able to withstand a wide range of temperatures and have a degree of moisture resistance as well as provide good adhesion. To provide all of these features, it hfew differentelps to put in additives to the adhesive.
Wet Strength Resins and Other Additives
Additives can improve specific characteristics in an adhesive. Additives can increase an adhesive’s thickness or viscosity, or it can expand the effective temperature range of the adhesive. Additives can also reduce an adhesive’s starch content or increase its shelf stability, which will in turn help to save money.
Some additives called wet strength resins can make an adhesive more resistant to moisture. This addresses a common problem with paper, which is that it tends to have a low wet strength. The term “Wet strength” refers to the material’s ability to be strong and resist tearing while wet.
Wet Strength is usually expressed as a ratio of strength while wet to strength while dry. Wet strength resins in the adhesive mix will increase the wet strength, add water resistance to the paper and increase the strength of the bond or even the paper itself.
RapidBond, Inc. is your source for all corrugating supplies, including adhesives, additives, resins and more. Visit rapidbond.net to learn about the full array of corrugating products and services they offer.
