Corrugated cardboard is one of the most widely used materials worldwide for the manufacture of packaging and containers, thanks to its strength, lightness, and protective capacity.
In its manufacturing process, starches act as adhesives in corrugators, playing a key role in bonding the different layers of paper that make up this composite material. Their proper use directly affects the final product’s quality, strength, and performance.
What is corrugated cardboard?
Corrugated cardboard consists of at least three layers of paper: an inner sheet, an outer sheet (also called face or liners), and a central fluted layer (known as fluting or corrugation).
These layers are bonded using an adhesive, usually starch-based, that ensures a permanent connection between them. The fluted design provides rigidity and mechanical strength, while the adhesive guarantees the structural stability of the whole assembly.
The role of the corrugator
The corrugator is the machine responsible for transforming flat paper into waves and bonding the different layers of cardboard. During this process, starch is applied to the tips of the fluting just before they come into contact with the liners or face paper. Then, through pressure and heat, the starch gelatinizes and fixes the layers together.
Why is starch used in the production of corrugated cardboard?
Starch is a natural polysaccharide that, when heated in the presence of water, swells and interlocks its molecular chains, forming a strong bond.
Because it comes from renewable sources such as wheat, corn, potato, or cassava, starch is widely available, low-cost, biodegradable, and safe for most industrial applications. Furthermore, starch is highly compatible with paper, which already contains starch from its own manufacturing process, helping to create strong and stable bonds.
Starch formulation for corrugated cardboard
In the production of corrugated cardboard, different starch formulations are used when working with native starches. All of them face the issue of raw material variability—whether from corn or wheat. Weather conditions like heat, cold, rain, or drought affect the protein content and composition of the cereal itself. Formulations must therefore be adapted to achieve consistent bonding results. This is where the company Crespel & Deiters has made a difference over the past 30 years with its Definol FK product line, where the starch formulation is prepared in-house and harvest variations are compensated for, ensuring consistent performance in the corrugator.
The desired properties of this adhesive include usage stability, proper viscosity, optimal drying time, and strong final bonding. Correctly adjusting these parameters with a factory reference allows for fast production without compromising the integrity of the cardboard.
Is starch just an adhesive?
In the manufacture of corrugated cardboard, starch is not merely an adhesive—it is a strategic component that directly affects the product’s performance, quality, and sustainability. Its proper selection, formulation, and application in corrugators are crucial to ensuring strong, uniform, and market-competitive cardboard. As the demand for sustainable packaging grows, starch will continue to play a vital role in innovation and improvement within the cardboard manufacturing process.
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