What is the current state of the fiberglass industry?
Introduction to Fiberglass
Fiberglass is a high-performance inorganic non-metallic material made from natural inorganic non-metallic minerals such as pyrophyllite, quartz sand, and limestone. It is produced through a series of processes including high-temperature melting, drawing, and winding, according to a specific formula. It possesses advantages such as good insulation properties, high mechanical strength, strong heat resistance, and good corrosion resistance, and is widely used in the automotive, electronics, wind power generation, shipbuilding, aerospace, construction, petroleum, and chemical industries. It is commonly used as a reinforcing material and is applied in various industries as composite materials.
Glass fiber can be classified in several ways, including by alkali metal oxide content, fiber properties, monofilament diameter, and fiber appearance. Based on the total content of alkali metal oxides (usually Na₂O and K₂O), it can be divided into alkali-free glass fiber (E glass fiber), medium-alkali glass fiber (C glass fiber), and high-alkali glass fiber (A glass fiber).
E glass fiber is made from aluminoborosilicate with an alkali metal oxide content of less than 1%. Globally, over 90% of glass fibers are E-glass fiber. E-glass fiber has good electrical insulation and mechanical properties, but poor acid resistance, making it unsuitable for acidic environments. It is widely used in applications requiring electrical insulation or as a reinforcing material.
Medium-alkali glass fiber typically contains 8%–12% alkali metal oxides. C-glass fiber accounts for approximately 5% of total glass fiber production. C-glass fiber has strong acid resistance, but poor electrical properties and lower mechanical strength than E-glass fiber. However, it is resistant to chemical corrosion and can be used in acid storage tanks and electroplating tanks, as well as in reinforcing asphalt roofing materials where mechanical strength requirements are lower.
A-glass fiber typically contains 14.5% or higher alkali metal oxides. A-glass fiber has poor water resistance; after being exposed to water, products made from it quickly become brittle and lose strength, rendering it unusable. It has been largely phased out.
Mainstream Production Methods
The main production methods for continuous glass fibers are crucible drawing and tank furnace drawing. The diameter of the resulting glass fiber monofilaments is generally 1.5μm~25μm, mostly 4μm~14μm.
(1) Crucible Drawing Method: First, various raw materials with specified compositions are crushed and then added to a glass tank furnace, where they are melted at a high temperature of about 1500°C. Then, glass spheres of a certain diameter are formed using a ball-making machine (hence the name "ball method"). The glass spheres are then added to a crucible containing a platinum baffle plate and remelted into a spinning melt, which flows out from the nozzle of the platinum baffle plate and is drawn into continuous glass fibers. This method has high energy consumption, low labor productivity, and unstable forming process, and has been largely phased out.
(2) Tank Furnace Drawing Method: This method omits the ball-making process. After the glass melt flows out from the holes of a platinum-rhodium alloy porous baffle plate, it is drawn into continuous glass filaments by a high-speed drawing machine. The resulting glass melt is directly drawn into fibers, hence the name "direct drawing method" or "one-step method." In addition, compared with the crucible drawing method, the tank furnace method has higher production capacity, better process controllability, and more stable product quality.
History of Fiberglass Development
In the 1930s, the businesses of Owens-Illinois Glass Company and Corning Glass Factory merged to form Owens Corning Fiberglass Company. After World War II, the global fiberglass industry developed rapidly, with continuous improvement in production technology, giving rise to a large number of fiberglass companies such as PPG Industries (USA), Saint-Gobain Group (France), and Nittobo (Japan). my country's fiberglass industry began in 1958. Before the reform and opening up, it was mainly used for national defense and military industries; after the reform and opening up, it shifted to civilian use and developed rapidly. With the continuous expansion of market demand, in recent years, my country's fiberglass yarn production has increased year by year. In 2023, my country's total fiberglass yarn production reached 7.23 million tons, a year-on-year increase of 5.2%.
Current Status and Problems
Among my country's fiberglass enterprises, China Jushi has the highest production capacity, accounting for about 34%; Taishan Fiberglass and Chongqing International Composites follow closely behind, each accounting for about 16%. In the research and development of high-performance glass fiber products, three companies-China Jushi, Taishan Glass Fiber, and Chongqing International Composites-possess first-class core technologies and a series of high-performance glass fiber products, making them key R&D and production enterprises for high-performance glass fiber in my country.
①. Small scale and quality of high-performance glass fiber and reinforced composite products Currently, my country's glass fiber production capacity, output, and production technology level are among the world's leading, but it faces a situation of overcapacity and serious homogenization of low-end products, while high-end products suffer from insufficient supply and weak competitiveness. Compared with the scale of high-performance glass fiber varieties abroad, the scale of various high-performance glass fiber products in my country is relatively small. Currently, the output of various high-performance and special glass fiber yarns (excluding high-modulus and ultrafine yarns), such as alkali-resistant, high-strength, low-dielectric, irregular-shaped, composite, body-colored, and high-silica, quartz, and basalt yarns, accounts for only about 1% of the total glass fiber output. Therefore, the output and quality of high-performance glass fiber and products cannot fully meet the needs of the high-end market.
②. Insufficient R&D in Glass Fiber and Product Manufacturing Technology and Equipment
While my country's ordinary glass fiber manufacturing technology and equipment have approached or reached international advanced levels, the manufacturing of high-performance specialty glass fibers, such as high-strength, low-dielectric, and high-silica types, still faces significant challenges in key indicators such as mechanical properties, electrical properties, and heat resistance. Furthermore, core technologies such as the optimized design of high-performance glass fiber components and performance, sizing agents and special film-forming agents, and deep processing of fiber products remain relatively weak, and production equipment levels are low, thus hindering the development of high-performance glass fibers towards high quality, large-scale production, and industrialization.
③. Uneven Development of Intelligent Manufacturing Among Enterprises
Leading enterprises and key backbone enterprises in the fiberglass industry attach great importance to intelligent manufacturing, demonstrating strong motivation and capability for intelligent upgrades, and exhibiting excellent levels and results in intelligent development. However, small and medium-sized enterprises, due to factors such as limited funds, insufficient technological accumulation, and talent shortages, lack the motivation and capability to promote intelligent manufacturing. The challenges these enterprises face during their intelligent transformation include, but are not limited to, high costs of equipment upgrades and replacements, difficulty in adapting to and mastering new technologies, and pressure to maintain a cost advantage in market competition. As a result, they lack the motivation to invest in intelligent upgrading and transformation, and their intelligent development is relatively slow.
