Key Points
- Mineral wool insulation products are partially made of binders that glue materials together. Conventional binder systems require specialized equipment and extremely high temperatures, limiting manufacturing possibilities.
- Researchers have begun looking into more environmentally friendly approaches to binder creation, though there is little understood about handling unwanted chemical emissions.
- A new direct thermal extraction gas chromatography–mass spectrometry (GC–MS) approach was tested for detecting volatile organic compound (VOC) emissions from lignin-based binders production and use.
Researchers from Rockwool, a stone wool insulation product company, and Aarhus University in Denmark developed a new gas chromatography-mass spectrometry (GC–MS)-based method of simulating emissions from mineral wool curing. Their research was published in the Journal of Chromatography A (1,2).
Mineral wool insulation products, which are typically used for thermal and acoustic insulation, have also found use in applications like plant growth and filtering. One example of such products is stone wool fibers, which are produced from various materials, such as basalt, anorthosite, and dolomite, as well as waste from other industries. Stone wool products can be described as composite materials made from stone wool fibers glued together by an adhesive, or a binder, typically at concentrations of 1–6 wt% of the fibers. While conventional binder systems perform well, they typically require specialized curing equipment that typically operates at extremely high temperatures (200–300 ºC). This can limit manufacturing possibilities and cause high energy consumption and high maintenance costs, all while producing process and product emissions that may require post-treatment.
To address these problems, researchers have begun looking into using more environmentally friendly and more sustainable binders for insulation materials. However, there is limited understanding of the performance and potential for unwanted chemical emissions from new binders, which could lead to environmental concerns in application of novel, green materials. Thorough investigations of volatile organic compound (VOC) emissions from lignin-based binders are vital.
In this study, the scientists developed a cost-effective and time-efficient laboratory method designed to simulate emissions from the mineral wool curing process using direct thermal extraction gas chromatography–mass spectrometry (DTE-GC–MS). Factors affecting VOC emissions, such as flow, residence time, and the atmosphere during the thermal desorption step, were investigated to identify the dominant factor influencing the chemical composition of emissions. Industrial processes could be better replicated. Additionally, a laboratory method was created to mimic factory-produced materials.
Analyzing the results from the emission simulation studies indicated that only the atmosphere proved to be a statistically significant parameter. The negligible effects of the flow rate, residence time, and their interactions can be attributed to the design of the DTE-GC–MS setup utilized in this research. Namely, the small sample size of uncured wool, introduced in glass tubes with approximately 1.9 mL volume, allowed for efficient heat transfer between the hot gas and the sample. Studied flow rates also varied from 7.8 to 60 tube volumes per minute, with sample temperatures closely following the thermal desorption unit’s temperature program, even at high flow rates.
The results showed that only the type of atmosphere in a thermal desorber during thermal desorption significantly affects emission compositions, with residence time and flow rates having statistically negligible impacts. Further, a short (6 min) method with a low flow rate (15 mL/min) was deemed sufficient to simulate curing-oven emissions effectively.
Strong correlations between laboratory and industrial emissions confirmed the method’s reliability for studying VOC emissions from real-world emissions. This allows for more accurate assessments of the environmental behavior of novel lignin-based binders while supporting the development of low-emission, sustainable materials. Using lignin-based binders can potentially reduce the environmental footprint compared to traditional PUF binders, contributing to more sustainable manufacturing practices. By establishing reliable methods for early-stage emission assessment, this study can facilitate the adoption of greener binder technologies aimed at minimizing unintended emissions.
References
(1) Homepage. Rockwool 2025. https://www.rockwool.com/north-america/ (accessed 2025-6-18)
(2) Salionov, D.; Nikolic, M.; Glasius, M. Emission Simulation Using Direct Thermal Extraction Gas Chromatography-Mass Spectrometry: Case Study with Curing of Lignin-Based Binder. J. Chromatogr. A 2025, 1753, 465970. DOI: 10.1016/j.chroma.2025.465970
