Wood release agents

For the Wood-Based Materials Industry – The Foundation for Trouble-Free Pressing Processes and Clean Surfaces

In the manufacture of wood-based materials such as MDF, OSB, and particleboard, the release agent plays a decisive role in determining the plant’s productivity. It protects the expensive steel belts to prevent the adhesion of wood fibers and particles, and ensures the surface quality of the finished board. What is often considered a secondary aspect of production has a direct impact on the uptime of hot presses. A precisely formulated release agent prevents unplanned production stoppages caused by time-consuming cleaning tasks.

Chemical-Physical Barrier Against MDI and UF Resins

The release effect in the hot press is based on a stable protective film. When applied in the correct amount, a wood release agent prevents highly adhesive adhesives such as MDI or UF resins from curing on the press plates. Products in the Multiboard series are formulated to remain on the metal surface rather than being absorbed into the wood fibers. This ensures that the adhesive does not come into contact with the metal. The result is longer cleaning intervals and production without downtime caused by wood residue on the steel or forming belt.

Thermal Stability: A reliable protective film even at high temperatures

Temperatures in the hot press exceed the limits of standard lubricants. Under these conditions, low-quality oils break down, evaporate, or form a crust. High-performance wood release agents counteract this thermal stress with a targeted combination of active ingredients:

Synthetic Esters

Synthetic Esters

They ensure thermal stability and form a durable barrier film even at temperatures above 200 °C.

Oxidation inhibitors

Oxidation inhibitors

Prevent the lubricant from reacting with oxygen in the air when exposed to heat.

Surfactant Additives

Surfactant Additives

They form a protective chemical layer that bonds directly to the steel strip and remains thermally stable.

Requirements for Adhesive Bonding and Painting

Minimal amounts of the release agent remain on the finished wood panel. These residues must not interfere with subsequent processing. Unsuitable products rely on nonpolar substances such as silicones or paraffin waxes, which form a separating boundary layer.

 

Preventing Loss of Adhesion and Crater Formation

Inferior release agent coatings prevent subsequent wetting by coatings or adhesives. This leads to typical defects in the final processing:

  • Loss of adhesion: Varnish components cannot form chemical bonds with the cellulose in the wood.
  • Crater formation: If the release agent is too hydrophobic, liquid varnish beads up and rolls off during surface coating.
  • Discoloration: Residues of unsuitable emulsifiers penetrate the varnish and interfere with its chemical curing.

Zeller+Gmelin’s formulations are designed to prevent these reactions. At the same time, so little of the substance remains on the panel that the end products—for example, in furniture manufacturing—remain odorless.

Requirements for Adhesive Bonding and Painting

Precise Application: Atomization and Surface Appearance

The application technique and the viscosity of the agent are directly interrelated. The finer the atomization of the release agent, the more evenly it is distributed across the surface of the steel strip. A seamless coating prevents the resin from coming into contact with the metal in specific spots. This avoids the formation of spots—known as “spotting”—and produces a homogeneous surface on the wood-based material.

Passivation Instead of Corrosion

In addition to their pure release function, the surfactant additives offer another benefit for the equipment. They passivate the metal surface of the press plates. Since the adhesive does not adhere, the metal remains protected from direct chemical and mechanical attacks, which increases the service life of the plates.

Multiboard Product Family: Custom Solutions for Your System

The wood-based materials industry is constantly evolving. With our Multiboard portfolio, we meet all requirements, from standard production to highly adhesive binders:

Multiboard FP-series

Water-miscible concentrates for the production of fiberboard and particleboard. They exhibit excellent release properties, particularly when bonding with UF/MUF binders, and allow for low application concentrations. The products are especially suitable for application via spray systems.

Multiboard Strand-Series

Low-foaming release agent concentrate developed specifically for the production of PMDI-bonded oriented strand board (OSB). It is suitable for application via roller and spray systems.

Multiboard FWP-Series

Release agent concentrates for the production of UF/MUF-bonded laminated formwork panels. These are suitable for application using rotary and roller systems.

Multiboard PMDI Cleaner

Water-soluble concentrate for removing stubborn pMDI buildup and residues from the system.

Reduce Your Process Costs with the Right Wood Release Agent

In wood-based panel production, release agents pay for themselves over the machine’s service life. A product precisely tailored to the press temperature and the resin system used reduces downtime for cleaning. It protects the steel belts and ensures consistent panel quality without scrap in the coating line.

Zeller+Gmelin has been developing lubricants and release agents for over 160 years. Take advantage of this technical expertise for your plant. Our sales team and our laboratory will analyze your specific process data—from the resin technology used to the application method—and identify the product that is precisely suited to your production process.

Reduce Your Process Costs with the Right Wood Release Agent

FAQ

The main sign is visible wood and resin residue on the steel or forming strip. These deposits inevitably lead to production stoppages, as the sheets must be thoroughly cleaned.

Isocyanate resins (pMDI) exhibit very high adhesive strength and form rapid chemical bonds with metal surfaces. Standard formulations for UF resins often fail to overcome these adhesive forces at molding temperatures above 200 °C. pMDI adhesive systems require specially formulated concentrates that form a thermally stable protective film to prevent the material from baking onto the press plate.

Low-foaming concentrates with optimized flow properties produce a uniform, thin coating. They leave no nonpolar boundary layers on the cellulose. As a result, the surface tension of the finished wood-based panel remains unchanged—it does not become hydrophobic—the liquid coating wets the surface optimally, and the consumption of adhesion promoters (primers) is reduced.

No. The amount of release agent that remains on the wood panel after the pressing process is minimal. It has virtually no effect on the smell of the finished product.

No. Because of the high temperatures—over 180 °C—in the plant, there is a serious fire hazard. For this reason, only water-based release agent emulsions are used in the wood-based materials industry.

Talk to our experts and schedule a one-on-one consultation to get advice on the right wood release agents for your specific application.

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