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Nachrichten, Termine, Experten
Nachrichten, Termine, Experten
The comparatively high weight of glass containers and the associated energy requirements during manufacturing and transport could be significantly reduced thanks to a joint material and technology development effort by EXXOSQEL GmbH and the Fraunhofer Institute for Silicate Research ISC. A novel surface treatment increases the mechanical strength of glass containers, thereby paving the way for thinner-walled and lighter glass-based packaging. A 15% weight reduction has already been achieved. With appropriately adapted and stable hot forming, the development partners believe that weight reductions of up to 40% will be technically feasible in the future.
Glass offers numerous advantages as a packaging material. Glass bottles and other glass containers are tasteless and odorless, do not release plasticizers or solvents, can be refilled multiple times in returnable systems, or can be returned to glass production as a valuable secondary raw material through the well-established glass recycling process, thereby saving energy. They therefore have excellent properties for packaging high-quality products such as food, medications, or cosmetics and can be very sustainable.
A major disadvantage is their relatively high weight compared to plastic containers or multilayer paper-metal-plastic composite packaging, as well as the high energy consumption during production and transport. For this reason, many current developments are focused on making glass thinner while simultaneously increasing its strength. “Given the requirements of the Packaging Regulation¹, how can we make glass lighter while maintaining the same strength so that glass packaging can compete with other packaging materials?” Thomas Sauer of EXXOSQEL outlines the goal of the development. This material development can directly contribute to reducing the carbon footprint of glass containers.
How can the breakage resistance of glass be increased?
Almost everyone has experienced this: A glass bottle falls to the floor and shatters into pieces. But glass can break even under comparatively small stresses. This is caused, for example, by thermal stresses resulting from rapid temperature changes or by surface defects and microcracks that can arise during production, filling, or transport. Improper handling in every-day use can also lead to this.
The thermal or chemical tempering processes commonly used in the flat glass sector, which increase strength by inducing targeted compressive stresses in the glass layer near the surface, are not widely used in the container glass industry, partly for technical reasons and partly due to the effort and cost involved. However, coatings applied immediately after hot forming (hot-end coating, HEC) and after the cooling oven (cold-end coating, CEC) are well established in the container glass industry. In the United States, American Glass Research reports that over 95% of container glass is treated in this way. Hot-end treatment is intended, for example, to increase the radii of microcracks and enable the adhesion of the cold-end treatment, while cold-end treatment improve the sliding properties of glass containers, thereby reducing wear during filling. Coatings based on polyethylene waxes are used for the cold-end coating. In the case of returnable bottles, the cold-end coating is largely washed off after just a few cycles due to the alkaline bottle washing process.
“Crack healing” through a new coating
The combination of a new coating material and optimized coating technology developed by EXXOSQEL and the Fraunhofer Institute for Silicate Research ISC largely bridges—or, so to speak, “heals”—surface defects. “Specifically, during the synthesis of multiple components, we create a three-dimensionally cross-linked composite whose matrix, after the coating is applied, forms covalent bonds at the molecular level within the microcracks created by hot forming and cooling,” explains Thomas Sauer, CEO of EXXOSQEL. This significantly increases the energy required to cause fracture. Laboratory tests have already demonstrated significant improvements in glass strength. For nearly all types of glass containers tested to date, the load withstood until fracture increased considerably in compression and impact tests. In some cases, the containers could not be broken even under the maximum load of 10 joules or 40 bar that the testing equipment could apply. The company estimates that thinner glass substrates could reduce material usage, energy consumption, and CO₂ emissions by enabling weight reductions of up to 40 percent, provided that stable hot-forming processes can be ensured. In addition, the coating creates a seamless surface. This results in greater brilliance and a better feel for each bottle. It also reduces friction between the bottles.
From the Laboratory Scale to the Prototype
The collaboration between EXXOSQEL and Fraunhofer ISC aims to bring the product to market. EXXOSQEL is developing the material formulation and is currently producing it on a laboratory scale with the support of Fraunhofer ISC. Fraunhofer ISC is also contributing its expertise in scaling up material synthesis and coating technologies for the next step from the laboratory to the pilot plant scale. Both research partners are working closely together on material formulation and technology development. The researchers in Würzburg are also supporting the scaling of the coating: “We want to design the application of the new coating so that it can be easily integrated into existing manufacturing processes,” says Dr. Ferdinand Somorowsky, head of coating technology at Fraunhofer ISC, emphasizing the application aspect. The partners are now working together on the next scaling step, explains Thomas Sauer: “We have mastered the experimental setup in the lab. For 2027, we plan to establish a pilot plant where we will further scale up both the production of the coating solution and the application technology. Our goal is to lay the groundwork for industry-relevant validation and the next step toward industrial mass production. In the next steps, we will involve partners from the container glass, beverage, and food industries, as well as from the machinery and plant engineering sectors.”
Project Information
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The development was funded through Bavaria’s Innovation Voucher Program
.
Project partners: EXXOSQEL GmbH, EXXERGY GmbH, Fraunhofer Institute for Silicate Research ISC
¹The EU Packaging and Packaging Waste Regulation (PPWR) has been in effect in all EU member states since August 12, 2026. In Germany, it is supplemented by the Packaging Law Implementation Act (VerpackDG).
Ferdinand Somorowsky
Fraunhofer Institute for Silicate Research ISC
Head of Chemical Coating Technology
ferdinand.somorowsky@
isc.fraunhofer.de
Thomas C. Sauer
EXXOSQEL GmbH
Management
info@exxosqel.com
Fig.1 A coating for healing microcracks—EXXOSQEL and Fraunhofer ISC aim to enable thinner-walled co ...
Copyright: © EXXOSQEL
Fig.2 A 100-liter stirred reactor for upscaling material syntheses
Source: K. Dobberke
Copyright: © Fraunhofer ISC
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Fig.1 A coating for healing microcracks—EXXOSQEL and Fraunhofer ISC aim to enable thinner-walled co ...
Copyright: © EXXOSQEL
Fig.2 A 100-liter stirred reactor for upscaling material syntheses
Source: K. Dobberke
Copyright: © Fraunhofer ISC
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