How do the diameter and length of glass microfiber affect the filtration efficiency and airflow resistance of air filter paper?
Release Time : 2025-12-05
In the field of high-performance air filtration, glass microfiber, due to its unique physical structure and stable chemical properties, has become a core material for manufacturing high-efficiency filter paper. Its filtration performance is not solely determined by "multi-layer stacking," but rather profoundly depends on the diameter and length of the fibers themselves—two microscopic parameters. These parameters together construct the three-dimensional network within the filter paper, directly regulating the particle interception capacity and the smoothness of airflow—the so-called balance between filtration efficiency and airflow resistance.
First, fiber diameter is a key factor affecting filtration efficiency. Centrifugation processes can draw molten glass into extremely fine micron-sized fibers. The smaller the diameter, the larger the total surface area per unit mass of fiber, resulting in finer pores. When dust-laden airflow passes through the filter paper, tiny particles are more easily captured by the fine fibers through mechanisms such as diffusion, interception, or inertial collision. Especially for submicron-sized particles (such as bacteria, smoke, or some viral carriers), ultrafine glass microfiber can significantly increase the capture probability, thereby achieving high filtration efficiency. However, excessively fine fibers can also lead to excessively high pore density, making the airflow path more tortuous, thus increasing flow resistance and causing increased fan energy consumption or decreased ventilation. Therefore, while pursuing ultimate filtration efficiency, the system's tolerance to air resistance must be considered.
Secondly, fiber length primarily affects the structural strength and pore uniformity of the filter paper. Longer glass microfibers are more likely to overlap and entangle during the web-forming process, forming a continuous and stable skeleton structure. This structure not only improves the mechanical strength of the filter paper, making it less prone to breakage during installation or operation, but also creates more uniformly distributed pore channels, avoiding localized "short circuits" or "blockages." Uniform pores mean a smoother airflow distribution, reducing additional resistance from turbulence and ensuring effective filtration across the entire filter surface, preventing premature local saturation. Conversely, if the fibers are too short, effective interweaving is difficult to achieve, resulting in loose, weak filter paper with inconsistent pore sizes, leading to excessive resistance in some areas and filtration failure in others.
More importantly, diameter and length need to be optimized synergistically. For example, using finer but sufficiently long fibers allows for the construction of a "fluffy yet strong" filter layer while maintaining a high specific surface area—it has numerous micropores for efficient dust capture and open channels to ensure low air resistance. This structure is precisely the ideal state pursued by high-end air filter papers (such as those used in cleanrooms or medical equipment). Modern centrifugal processes, through precise control of melt temperature, centrifugation speed, and cooling conditions, can stably produce glass microfibers with suitable diameters and lengths, providing high-quality raw materials for subsequent wet forming.
Furthermore, the geometric properties of the fibers also affect the distribution of the binder and the curing effect. During thermosetting or resin reinforcement, a uniform fiber network helps to rationally distribute the bonding points, enhancing the overall structure without excessively clogging the pores. If the fibers are uneven in thickness and length, more binder is needed to maintain strength, sacrificing air permeability.
In conclusion, the diameter and length of glass microfiber are not isolated parameters, but rather the warp and weft threads that together weave the "functional network" of the filter paper. Fine diameter enhances the trapping power, while long fibers ensure structural stability; the exquisite combination of the two achieves the optimal balance between "blocking" and "allowing" air to pass through. This is the unseen science and art behind high-performance air filter paper—building a screen of cleanliness with micron-sized fibers.
First, fiber diameter is a key factor affecting filtration efficiency. Centrifugation processes can draw molten glass into extremely fine micron-sized fibers. The smaller the diameter, the larger the total surface area per unit mass of fiber, resulting in finer pores. When dust-laden airflow passes through the filter paper, tiny particles are more easily captured by the fine fibers through mechanisms such as diffusion, interception, or inertial collision. Especially for submicron-sized particles (such as bacteria, smoke, or some viral carriers), ultrafine glass microfiber can significantly increase the capture probability, thereby achieving high filtration efficiency. However, excessively fine fibers can also lead to excessively high pore density, making the airflow path more tortuous, thus increasing flow resistance and causing increased fan energy consumption or decreased ventilation. Therefore, while pursuing ultimate filtration efficiency, the system's tolerance to air resistance must be considered.
Secondly, fiber length primarily affects the structural strength and pore uniformity of the filter paper. Longer glass microfibers are more likely to overlap and entangle during the web-forming process, forming a continuous and stable skeleton structure. This structure not only improves the mechanical strength of the filter paper, making it less prone to breakage during installation or operation, but also creates more uniformly distributed pore channels, avoiding localized "short circuits" or "blockages." Uniform pores mean a smoother airflow distribution, reducing additional resistance from turbulence and ensuring effective filtration across the entire filter surface, preventing premature local saturation. Conversely, if the fibers are too short, effective interweaving is difficult to achieve, resulting in loose, weak filter paper with inconsistent pore sizes, leading to excessive resistance in some areas and filtration failure in others.
More importantly, diameter and length need to be optimized synergistically. For example, using finer but sufficiently long fibers allows for the construction of a "fluffy yet strong" filter layer while maintaining a high specific surface area—it has numerous micropores for efficient dust capture and open channels to ensure low air resistance. This structure is precisely the ideal state pursued by high-end air filter papers (such as those used in cleanrooms or medical equipment). Modern centrifugal processes, through precise control of melt temperature, centrifugation speed, and cooling conditions, can stably produce glass microfibers with suitable diameters and lengths, providing high-quality raw materials for subsequent wet forming.
Furthermore, the geometric properties of the fibers also affect the distribution of the binder and the curing effect. During thermosetting or resin reinforcement, a uniform fiber network helps to rationally distribute the bonding points, enhancing the overall structure without excessively clogging the pores. If the fibers are uneven in thickness and length, more binder is needed to maintain strength, sacrificing air permeability.
In conclusion, the diameter and length of glass microfiber are not isolated parameters, but rather the warp and weft threads that together weave the "functional network" of the filter paper. Fine diameter enhances the trapping power, while long fibers ensure structural stability; the exquisite combination of the two achieves the optimal balance between "blocking" and "allowing" air to pass through. This is the unseen science and art behind high-performance air filter paper—building a screen of cleanliness with micron-sized fibers.