Adhesives, Additives, Coatings and Wet Strength Resins

Paper is a material that people love to use for a number of different purposes, and as such, it should probably be admired for its versatility. But paper does have limitations, and in order to use paper more effectively, it’s often necessary to use adhesives, additives, coatings and wet strength resins. In the corrugating process, in particular, these four types of products can be quite useful. They are often used in corrugating machines, many of which have the equipment to actually mix these products as part of the overall machine.

Paper Adhesives
When using paper to make corrugated material, an adhesive is an essential component. Corrugated material is basically a sandwich made from rigid outer paper sheets with fluted paper glued in between. The adhesive is often cured with heat to achieve a better bond and remove moisture. The adhesive needs to be able to withstand a wide range of temperatures and be resistant to moisture while providing good adhesion. The best adhesives are sustainable, being made from renewable starch material like corn, tapioca, wheat or potato.

Sometimes an adhesive can have specific characteristics improved with an additive. Additives might be put into an adhesive to thicken it up or thin it out, or they might be used to add greater resistance to temperature or moisture. Some additives can also reduce starch content, increase shelf stability and reduce cost.

Paper can often be strengthened by the application of a coating. These coatings can also add color to paper or corrugated material. These coatings are also often printable, glue-able and wax-able. Coatings may also add water or crease resistance.

Wet Strength Resins
One of the great problems with paper as a material to work with is that it tends to lose its strength and tear easily when it gets wet. The term used to refer to this characteristic is “Wet strength” and it is often expressed as a ratio of strength while wet to strength while dry. One way to partially offset this characteristic is to add wet strength resins to the paper or the adhesive. These substances can add water resistance to the paper and/or increase the strength of the paper or the bond.

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