New Insights Into Hornification for Stronger Paper Production

New research into the phenomenon of hornification, reported on April 1, 2026, has revealed that the process is more complex than previously assumed, offering potential improvements for the strength and durability of paper production.

Hornification occurs when paper dries and is subsequently rewetted, resulting in permanent changes to its properties. Specifically, this process causes fibers in paper products to lose a portion of their ability to absorb water.

These changes have significant implications for both paper manufacturing and recycling, as controlling the material’s durability and strength is essential to these industrial processes.

The Drivers of Hornification

The study indicates that temperature, humidity, and fiber type all play decisive roles in how hornification affects the material. A primary conclusion of the research is that the removal of water, rather than the application of heat, is the primary driver of the process.

To verify this, researchers separated the effects of high temperature from the drying process. The results demonstrated that heat alone has almost no influence on the structure of the fibers.

Björn Sjöstrand, Associate Professor of Chemical Engineering and project leader for the research, stated that Fundamentally, hornification is more about removing water than adding heat, and this means that we can actually control the material’s properties and avoid unnecessary strength losses.

The Temperature Dip Zone

One of the most significant findings of the research is that hornification does not increase at a steady rate as temperature rises. Instead, researchers identified a distinct dip zone when drying occurs between 40–60°C.

Within this specific temperature range, structural changes in the fibers are minimal, and the resulting material is at its strongest.

This pattern has now been confirmed across several different pulp types, providing evidence that supports earlier isolated observations reported in previous studies.

Fiber Type Variations

The research further clarifies how different raw materials react to the drying and rewetting process. The results show that hardwood pulp is affected more by hornification than softwood pulp.

By understanding these variables—specifically the role of water removal over heat and the impact of fiber type—manufacturers may be better able to control the properties of paper products to prevent strength loss.