glass fiber

Fiberglass is an excellent inorganic non-metallic material with a wide variety of types. Its advantages include strong heat resistance, good corrosion resistance, and high mechanical strength. However, it is brittle and has poor wear resistance. It is made from mineral raw materials such as mica, quartz sand, limestone, dolomite, borocalcite, and boromagnesite through processes such as high-temperature melting, drawing, spinning, and weaving. The diameter of a single fiber ranges from a few micrometers to over thirty micrometers, equivalent to 1/20 to 1/5 of a hair strand. Fiberglass is commonly used as a reinforcing material in composite materials, electrical insulation materials, thermal insulation materials, circuit boards, and various sectors of the national economy.

The basic properties of fiberglass

– The density of fiberglass falls between that of organic fibers and metallic fibers (2.7)
– It has a higher tensile strength
– Good dimensional stability
– And high hardness

The classification of fiberglass

1. Classification based on glass composition
– E-glass, alkali-free glass: Alkali metal oxide content is less than 0.8%. Characteristics: stable chemical properties, excellent electrical insulation performance, good mechanical strength.
– C-glass, medium-alkali glass: Alkali metal oxide content is 11.6%-12.4%. It has better acid resistance than alkali-free glass, but poorer electrical properties and 10%-20% lower mechanical strength than alkali-free glass fiber.
– A-glass, high-alkali glass: Alkali metal oxide content is above 16%, also known as clay glass fiber.

Its mechanical properties are much lower than alkali-free and medium-alkali glass fiber, and it is not resistant to water erosion. Under moisture erosion in the atmosphere, products made from A-glass quickly become brittle. It was an early product of China’s glass fiber industry and is now being phased out. The production of high-alkali fiber products using clay crucibles has been explicitly abolished by the government, and it cannot be used as a reinforcing material for fiberglass. However, high-alkali fiber produced without clay crucibles can still be used to produce acid-resistant products. Alkali resistance, insulation, and mechanical properties: E > C > A. Acid resistance: E < C < A.
Alkali metal oxides generally refer to sodium and potassium metal oxides, namely Na2O and K2O. Alkali metal oxides are one of the main components of ordinary glass and their main function is to lower the melting point of the glass. The higher the content of alkali metal oxides, the more stable the chemical properties of the glass fiber, but the corresponding electrical insulation performance and strength will decrease.

Differences in glass formulations

TypesAcid resistanceWater resistanceMechanical strengthResistance to agingElectrical insulationImpregnating agentHeat resistance
E-glassin generalgoodhighrelatively goodgoodresin easily penetratesgood
C-glassrelatively goodin generalrelatively lowin generallowresin easily penetratesin general
A-glassgoodlowrelatively lowpoorlowpoor resin penetrationpoor

Specialized glass fibers
– High-strength S-glass fiber composed of pure silicon-magnesium-aluminum ternary system.
– Silicon-magnesium-aluminum-based high-strength, high-modulus glass fiber.
– Silicon-aluminum-calcium-magnesium-based corrosion-resistant glass fiber.
– Lead-containing fiber.
– High-silica fiber.
– Quartz fiber.
– Conductive fiber.
– Low-dielectric fiber.

2 . Classification based on single fiber diameter

– Coarse fiber: 30 μm
– Primary fiber: 20 μm
– Intermediate fiber: 10 μm – 20 μm
– Fine fiber: 3 μm – 10 μm (also known as textile fiber)
– Ultrafine fiber: Single fiber diameter less than 4 μm

The difference in single fiber diameter not only affects the performance of the fiber but also influences the production process, yield, and cost of the fiber. Generally, fibers with a diameter of 5 μm – 10 μm are used for textile products. Fibers with a diameter of 10 μm – 14 μm are suitable for untwisted yarn, non-woven fabrics, and short-cut fiber felts.

glass fiber

3. Classification based on appearance:
– Untwisted yarn
– Grid fabric
– Short-cut felt
– Various types of woven fabrics
– Short-cut staple fiber
– Ground glass fiber (glass fiber crushed into small pieces)

Fiberglass product structure

Fiberglass consists of inorganic components (glass) and organic components (impregnating agent).

The core technology of fiberglass – impregnating agent

The role of the impregnating agent:

1. Lubrication and protection.
2. Bonding and bundling.
3. Prevention of static accumulation on the surface of fiberglass.
4. Classification of impregnating agents:

Classification of impregnating agents:

A. Textile-type impregnating agents: These impregnating agents have good weaving performance, resulting in smooth yarn without fuzz. They are divided into starch-based and paraffin-based types. After application, they require post-processing. Currently, they are rarely used except for fine yarns.

B. Reinforcing-type impregnating agents: These impregnating agents contain components such as coupling agents, film-forming agents, and lubricants. They can directly bond with the resin.

C. Textile-reinforcing impregnating agents: These impregnating agents combine the characteristics of textile-type and reinforcing-type impregnating agents. They can be used for weaving or used directly.

Components of impregnating agents:

A. Coupling agents: They play a bridging role between the inorganic components and the matrix resin.
B. Lubricants: They ensure smooth production and processing of fiberglass, meeting the requirements of subsequent use.
C. Film-forming agents: They provide a bonding and bundling effect on fiberglass.
D. Additives: These are auxiliary components that may be included in the impregnating agents.

Advantages of pool kiln fiber drawing

1. Direct drawing from powder: Eliminates the need for the pelletization process.
2. Simplified process and stable product quality.
3. High production capacity: For example, China’s Jushi Group has the world’s largest pool kiln with an annual production capacity of 140,000 tons.
4. Low energy consumption: Utilizes natural gas as fuel and employs advanced pure oxygen combustion technology, achieving low-energy and clean production.

Glass Fibers

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Contact Person: Mr. Jason Hu

Tel: +86 132 0712 7986

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