Centrifugal glass wool is a man-made inorganic fiber material made by fiberizing molten glass liquid through a high-speed centrifugal process with natural minerals such as quartz sand, limestone, and dolomite as the main raw materials. Its fiber diameter refers to the microscopic scale of a single glass fiber, usually measured in microns (μm). Depending on the production process and formula, the fiber diameter range of centrifugal glass wool is mainly between 3-8 microns, while we high-end glass wool products can be further reduced to 4-5.5 microns. ). This diameter scale is only 1/20 to 1/50 of a human hair, which is a typical micron-level ultra-fine fiber material.
The precise measurement of fiber diameter is usually completed by scanning electron microscopy (SEM) combined with image analysis technology. The high-resolution microscopic image of the fiber is obtained by scanning electron microscopy, and then the diameters of hundreds of fibers in multiple randomly selected fields of view are statistically measured using professional software, and finally, the average diameter and diameter distribution are calculated. Research shows that the uniformity of fiber diameter is equally important to material performance. The more concentrated the diameter distribution range, the better the structural uniformity of the material and the more stable the performance. In actual production, the control of fiber diameter depends on the precise regulation of key process parameters such as melting temperature, centrifugal speed, and airflow drafting force, which requires high-level production technology and long-term experience accumulation.
As the core structural parameter of centrifugal glass wool, fiber diameter directly determines the porous structural characteristics of the material, which in turn affects its core physical properties. As the fiber diameter decreases, a richer and more uniform microporous structure is formed inside the material. These microstructural changes give the material excellent comprehensive performance.
1. Heat conduction mechanism: The thermal insulation performance of centrifugal glass wool mainly depends on the thermal insulation effect of its "solid-gas phase" composite structure. When the fiber diameter is reduced to below 5μm, a large number of micropores with a diameter of 10-50μm are formed inside the material. These pores can effectively restrict the movement of air molecules and greatly reduce the efficiency of air heat conduction. At the same time, the complex three-dimensional network formed by ultrafine fibers increases the tortuosity of the heat conduction path and significantly extends the heat transfer path.
2. Relationship between diameter and thermal conductivity: Experimental data show that the thermal conductivity can be reduced by about 10-15% for every 1μm reduction in fiber diameter. When the fiber diameter is ≤5μm, the thermal conductivity can be reduced to 0.033-0.041W/(m·K), which is much lower than that of traditional glass wool (0.043-0.052W/(m·K)). When the fiber diameter is less than 1μm, the thermal conductivity decreases more significantly with the decrease in diameter. This change is due to the nanoscale effect, when the molecular vibration on the fiber surface has a more obvious hindering effect on heat transfer.
1. Acoustic energy conversion mechanism: The sound absorption performance of centrifugal glass wool is derived from its porous material properties. When sound waves are incident on the surface of the material, they can enter the material through the interconnected pores, causing the vibration of air molecules in the pores. Due to the viscous resistance of the air and the friction between the air molecules and the fiber surface, the sound energy is converted into heat energy and lost.
2. The influence of fiber diameter: The fiber diameter directly affects the flow resistance characteristics of the material and then determines the sound absorption efficiency. Ultrafine fibers (diameter ≤5μm) form a more dense and complex microporous network, which significantly increases the viscous resistance and friction loss of the sound wave propagation path. Experiments show that under the same thickness and density conditions, the sound absorption coefficient of glass wool with a diameter of 5μm in the low frequency band of 125-500Hz is 40-60% higher than that of 8μm products, which can more effectively solve the low-frequency noise problem in buildings. At the same time, the high-frequency sound absorption coefficient (>2000Hz) of ultrafine fiber materials can be close to 1.0, achieving efficient sound absorption in almost the entire frequency band.
1. Structural stability: The reduction in fiber diameter significantly increases the specific surface area and inter-fiber contact points of the material, and under the action of thermosetting resin binder, a more dense and stable three-dimensional network structure is formed. This structure gives ultrafine fiber glass wool higher tensile strength and anti-compression resilience, and is not prone to sedimentation and deformation during long-term use.
2. Heat resistance and fire resistance: The ultrafine fiber structure improves the thermal stability of the material. When the density is increased to 64kg/m³, the heat load shrinkage temperature can reach above 400℃, which is much higher than conventional products (250℃), and can maintain structural integrity and thermal insulation functions for a longer time under fire conditions. At the same time, the Class A fireproof performance (GB8624 standard) of ultrafine fiber glass wool prevents it from releasing toxic gases in high temperature environments, and its safety performance is more reliable.
Table: Trend of fiber diameter's influence on key properties of centrifugal glass wool
|
Performance Indicators |
Fiber Diameter 5μm |
Fiber Diameter 8μm |
Performance Improvement Range |
|
Thermal Conductivity (W/(m·K)) |
0.033-0.041 |
0.042-0.052 |
Reduced by 20-30% |
|
Low Frequency Sound Absorption Coefficient (125Hz) |
0.6-0.7 |
0.2-0.4 |
Increased by 40-60% |
|
Heat Shrinkage Temperature (°C) |
≥400 (64kg/m³) |
≥250 (24kg/m³) |
Increased by more than 60% |
|
Moisture Resistance (%) |
≥98.2 |
≥90 |
Improved by 8-10 percentage points |
The fiber diameter of centrifugal glass wool, as a core structural parameter, has a decisive influence on the thermal, acoustic, mechanical and safety performance of the material. The current national standards (GB/T 17795-2019, GB/T 13350-2017) require a fiber diameter of ≤8.0μm, which can no longer meet the needs of high-quality construction projects, especially in ultra-low energy consumption buildings, acoustically sensitive spaces, extreme industrial environments and other application scenarios.
Engineering practice shows that the use of ultra-fine centrifugal glass wool with a fiber diameter of ≤5μm, combined with a strict quality recognition and pricing mechanism and node optimization design, can achieve an increase of more than 30% in thermal insulation and energy-saving efficiency, 40-60% improvement in low-frequency noise absorption, and an extension of service life of more than 25 years.
If you have high-quality glass wool felt purchase needs or want to learn more about the product, you are welcome to contact us IKING GROUP.
CHINA IKING INDUSTRIAL GROUP CO., LTD. glass wool factory was established in 1995 and is located in Tianjin. It is one of the leading glass wool supplier in China.....[ Read More >>]
