The main uses of fiberglass

Untwisted coarse yarn is composed of parallel strands or parallel monofilaments bundled together. Twistless roving can be divided into alkali free glass and medium alkali glass based on glass composition. The diameter of glass fibers used in the production of glass roving ranges from 12 to 23 μ M. The count of untwisted coarse yarn ranges from 150 to 9600 (tex). Untwisted roving can be directly used in certain composite material forming methods, such as winding and extrusion processes. Due to its uniform tension, it can also be woven into untwisted roving fabrics, and in some applications, it can be further shortened.
(1) Twistless roving for jet molding is suitable for fiberglass injection molding. Twistless roving should have the following properties: ① good cutting performance, less static electricity generated during continuous high-speed cutting; ② The efficiency of dispersing untwisted coarse yarn into raw silk after cutting is high, that is, the splitting rate is high, usually requiring more than 90%; ③ The short cut raw silk has excellent covering ability and can cover all corners of the mold; ④ Resin penetrates quickly, is easy to be flattened by rollers, and is easy to drive away bubbles; ⑤ The unwinding performance of the raw silk drum is good, and the yarn density of the coarse yarn is uniform, suitable for various spray guns and fiber conveying systems. Jet spun roving is made by winding multiple strands of raw silk, with each strand containing 200 fiberglass monofilaments.
(2) SMC uses untwisted coarse yarn SMC, also known as sheet molded plastic, mainly used to press automotive components, bathtubs, water tank boards, purification tanks, various seats, etc. When manufacturing SMC sheets, untwisted roving for SMC needs to be cut into a length of 25mm and dispersed in resin paste. Therefore, the requirements for using untwisted roving for SMC are good short cut, less yarn, excellent anti-static properties, and the short cut thread will not adhere to the cutting roller during cutting. For colored SMC, untwisted roving needs to be impregnated with resin in a high pigment content resin paste. Usually, SMC untwisted roving is 2400tex, and in a few cases, 4800tex is also used.
(3) The winding method using untwisted coarse yarn is used to manufacture various diameters of fiberglass pipes, storage tanks, etc. The number of untwisted roving used for winding ranges from 1200 to 9600, and large pipelines and storage tanks tend to prefer direct untwisted roving, such as 4800 tex direct untwisted roving. The requirements for untwisted roving used for winding are as follows: ① Good tape forming performance, in a flat strip shape; ② Untwisted coarse yarn has good unraveling properties, does not shed loops when unraveled from the yarn barrel, and does not form bird's nest like tangled threads; ③ Uniform tension without any overhanging phenomenon; ④ Uniform linear density, generally less than ± 7%; ⑤ Twistless roving has good permeability and is easily wetted and soaked by resin when passing through resin grooves.
(4) Twistless coarse yarn is used for extrusion to manufacture various profiles with consistent cross-sections, characterized by high fiberglass content and high unidirectional strength. Twistless roving used for pultrusion can be a combination of multiple strands of raw silk or a direct type, with a linear density range of 1100 to 4400. The various performance requirements are generally the same as those for winding untwisted roving.
(5) One important use of untwisted roving for weaving is to weave various thicknesses of checkered or unidirectional untwisted roving fabrics, which are mostly used in hand lay fiberglass forming processes. The following requirements are required for non twisted roving for strong manufacturing: ① good wear resistance; ② Good banding ability; ③ Twistless roving for weaving needs to be forcibly dried before weaving; ④ The tension of untwisted roving should be uniform, and the drape should meet certain standards; ⑤ Twistless roving has good unraveling properties; ⑥ Twistless roving has good permeability.
(6) In the preform process, the untwisted coarse yarn is cut short and sprayed onto a predetermined shaped mesh. At the same time, a small amount of resin is sprayed to fix the fiber mesh into shape. Then, the formed fiber mesh is moved into a metal mold and injected with resin for hot pressing to obtain the product. The performance requirements for this process of untwisted roving are basically the same as those for jet spun untwisted roving. Checker cloth is a plain weave fabric made of untwisted coarse yarn, and is an important substrate for hand laid fiberglass. The strength of checkered fabric mainly lies in the warp and weft directions of the fabric. For situations where high warp or weft strength is required, unidirectional checkered fabric can also be woven, which can arrange more untwisted coarse yarn in the warp or weft directions.
The quality requirements for each other's plaid are as follows: ① The fabric is uniform, the edges are straight, the fabric surface is flat and in a mat shape, without stains, fuzzing, creases, wrinkles, etc.; ② The warp and weft density, area weight, fabric width, and roll length all meet the standards; ③ Wrap it neatly on a sturdy paper core; ④ Rapid and good resin permeability; ⑤ The dry and wet mechanical strength of laminated materials made of fabrics should meet the requirements.
The composite material formed by laying grid cloth is characterized by low interlayer shear strength, poor compressive and fatigue strength. (1) The chopped strand mat cuts the glass strand (sometimes with untwisted roving) into 50 mm long, spreads it on the mesh belt randomly but evenly, and then applies lotion binder or spreads powder binder, after heating and curing, it is bonded into chopped strand mat. Short cut felt is mainly used in hand layup, continuous board making, die pressing, and SMC processes. The quality requirements for short cut raw silk felt are as follows: ① uniform area quality along the width direction; ② The short cut raw silk is evenly distributed in the felt surface, without the formation of large pores, and the adhesive is evenly distributed; ③ Has moderate dry felt strength; ④ Excellent resin infiltration and permeability.
(2) Continuous strand felt is made by laying the glass strand formed during the drawing process or the continuous strand released from the strand cylinder in an 8-shaped pattern on a continuous moving mesh belt, and bonding it with a powder binder. The fibers in continuous fiberglass felt are continuous, so its reinforcement effect on composite materials is better than that of short cut felt. Mainly used in processes such as extrusion, RTM, pressure bag, and glass felt reinforced thermoplastic (GMT).
(3) Surface felt fiberglass products usually require the formation of a resin rich layer, which is usually achieved using medium alkali glass surface felt. This type of felt is made of medium alkali glass (C), which endows fiberglass with chemical resistance, especially acid resistance. At the same time, due to the thin felt and small diameter of fiberglass, it can absorb more resin to form a resin rich layer, covering the patterns of fiberglass reinforcement materials (such as checkered cloth) and playing a surface modification role.
(4) Needle punched felt can be divided into short cut fiber needle punched felt and continuous filament needle punched felt. Short cut fiber needle felt is a method of cutting fiberglass coarse yarn into 50mm short pieces and randomly laying them on a substrate pre placed on a conveyor belt. Then, a needle with a hook is used to needle the short cut fibers into the substrate, and the hook needle lifts some fibers upwards to form a three-dimensional structure. The substrate used can be a thin fabric of glass fiber or other fibers, and this type of needle punched felt has a fuzzy feeling. Its main uses include being used as insulation and sound insulation materials, lining heat materials, filtering materials, and can also be used in the production of fiberglass. However, the strength of the produced fiberglass is relatively low and its range of use is limited. Another type of continuous strand needle punched felt is a felt that randomly throws continuous glass strands onto a continuous mesh belt using a wire throwing device, and forms a three-dimensional structure with fibers hooked together through needle plates. This type of felt is mainly used for the production of glass fiber reinforced thermoplastic stamping sheets.
(5) Short cut glass fibers can be sewn into short cut fibers or long fiber felt using a sewing machine, ranging from 50mm to 60cm in length. The former can replace traditional adhesive bonded short cut felt in several applications, while the latter can to some extent replace continuous filament felt. Their common advantage is that they do not contain binders, avoiding pollution in the production process, while also having good penetration and bonding performance, and a lower price. (1) Short cut raw silk is divided into dry cut raw silk and wet cut raw silk. The former is used in the production of reinforced plastics, while the latter is used in papermaking. The short cut precursor used for fiberglass can be divided into two categories: short cut precursor for reinforced thermosetting resin (BMC) and short cut precursor for reinforced thermoplastic resin. The requirement for using short cut precursor for reinforced thermoplastic plastics is to use alkali free glass fiber, which has high strength and good electrical insulation. The short cut precursor has good bundling properties, good flowability, and high whiteness. Enhanced thermosetting plastic short cut precursor fibers require good bundling properties, are easy for resin to quickly penetrate, and have good mechanical strength and electrical properties.
(2) Grinding fibers are made by grinding short cut fibers with a hammer mill or ball mill. Milled fibers are mainly used as reinforcing materials in reinforced reaction injection molding (RRIM) processes, and as resin fillers in the manufacturing of cast products, molds, and other products to improve surface cracking and reduce mold shrinkage. They can also be used as reinforcing materials. The following are various fiberglass fabrics woven from fiberglass yarns.
(1) The glass cloth produced in China is divided into two categories: alkali free and medium alkali free, with most foreign countries using alkali free glass cloth. Glass cloth is mainly used for producing various electrical insulation laminates, printed circuit boards, vehicle bodies, storage tanks, boats, molds, etc. Medium alkali glass cloth is mainly used in the production of plastic coated packaging cloth and for corrosion-resistant occasions. The characteristics of a fabric are determined by fiber properties, warp and weft density, yarn structure, and texture. The warp and weft density is determined by the yarn structure and texture. The combination of warp and weft and yarn structure determines the physical properties of a fabric, such as weight, thickness, and fracture strength. There are five basic weaving patterns: plain, twill, satin, ribbed, and mat.
(2) Glass strips are divided into woven edge strips and non-woven edge strips (burrs). The main weaving method is plain weave. Glass strips are commonly used to manufacture electrical equipment components with high strength and good dielectric properties.
(3) Unidirectional fabric is a four warp broken satin or long axis satin fabric woven from coarse warp and fine weft yarns. Its characteristic is high strength in the main warp direction.
(4) Compared to flat fabrics, three-dimensional fabrics have developed their structural characteristics from one-dimensional and two-dimensional to three-dimensional, which makes composite materials reinforced with them have good integrity and shape imitation, greatly improving the interlayer shear strength and damage resistance tolerance of composite materials. It has developed with the special needs of sectors such as aerospace, aviation, weapons, and ships. Today, its applications have expanded to sectors such as automobiles, sports equipment, and medical equipment. There are mainly five types: machine woven three-dimensional fabrics, knitted three-dimensional fabrics, orthogonal and non orthogonal non-woven three-dimensional fabrics, three-dimensional woven fabrics, and other forms of three-dimensional fabrics. The shapes of three-dimensional fabrics include block, column, tube, hollow truncated cone, and variable thickness irregular cross-section.
(5) The shape of the irregular fabric is very similar to the shape of the product it is intended to enhance, and it must be woven on a dedicated loom. Asymmetric shaped fabrics include round covers, cones, caps, dumbbell shaped fabrics, and can also be made into asymmetric shapes such as boxes and ship shells.
(6) Slot core fabric is a fabric composed of two parallel layers connected by longitudinal vertical bars, with a cross-sectional shape that can be triangular or rectangular.
(7) Fiberglass knitted fabric, also known as knitted felt or woven felt, is different from both ordinary fabrics and the usual sense of felt. The most typical knitted fabric is a layer of warp and weft yarns that overlap and are woven together through sewing to form a fabric. The advantages of knitted fabrics are as follows: ① It can increase the ultimate tensile strength, delamination resistance under tension, and bending strength of fiberglass laminated products; ② Reduce the weight of fiberglass products; ③ Smooth surface makes the fiberglass surface smooth; ④ Simplify hand layup operations and improve labor productivity. This reinforcing material can replace continuous strand felt in the extrusion process of fiberglass and RTM, and can also replace checkered cloth in the centrifugal process of fiberglass production.
(8) Glass fiber insulation sleeve is woven into a tube with glass fiber yarn. And coated with various insulation grades of resin materials There are PVC resin fiberglass paint pipes. Since the 1970s, there have been reinforcement materials that combine short cut strand felt, continuous strand felt, untwisted coarse yarn fabric, and untwisted coarse yarn in a certain order, such as acrylic fiberglass paint pipes and silicone resin fiberglass paint pipes. There are generally the following types:
(1) Short cut raw silk felt+untwisted coarse yarn fabric
(2) Short cut raw silk felt+untwisted coarse gauze+short cut raw silk felt
(3) Short cut strand felt+continuous strand felt+short cut strand felt
(4) Short cut raw felt+random untwisted coarse yarn
(5) Short cut raw silk felt or cloth+unidirectional carbon fiber
(6) Short cut raw silk+surface felt
(7) Glass cloth+unidirectional untwisted coarse yarn or glass rod+glass cloth
Glass fiber wet felt
The glass fiber non-woven fabric series products originated in Europe and were later introduced to countries such as the United States, Japan, and China. China has established several large-scale production lines, mainly relying on German technologies such as ZTE Tianma in Changzhou and Shaanxi Huate.
The main categories of domestic fiberglass wet felt are:
(1) Roof felt is used as a base material for modified asphalt waterproofing membranes, colored asphalt tiles, and other waterproofing materials
(2) Pipeline felt is used for coating oil and gas pipelines, combined with asphalt to prevent corrosion of underground pipelines
(3) Shaping and surface polishing of surface felt fiberglass products
(4) Veneer felt is used for walls and ceilings, which can prevent paint cracking and orange peel. It is often used to decorate large conference rooms and high-end hotels
(5) Floor felt used as a substrate for PVC flooring
(6) Carpet felt used as a substrate for square carpets
(7) Adhesion of copper-clad sheet felt to copper-clad sheet can enhance its punching and drilling performance
(8) Battery partition felt is used as the substrate for aluminum acid battery partition felt. Mainly used in the fiberglass industry (accounting for about 70%). The construction industry also uses fiberglass cloth, whose main function is to increase strength. Also used as insulation layer for building exterior walls, interior wall decoration, interior wall moisture-proof and fireproof, etc
Varieties of fiberglass cloth: fiberglass mesh cloth, fiberglass square cloth, fiberglass plain cloth, fiberglass axial cloth, fiberglass wall cloth, fiberglass electronic cloth.
Glass fiber function:
1. Enhance rigidity and hardness. The increase in fiberglass can improve the strength and rigidity of plastics, but the toughness of the same plastic will decrease. Example: Bending modulus;
2. Improve heat resistance and hot deformation temperature; Taking nylon as an example, with the addition of fiberglass, the thermal deformation temperature of nylon can be increased by at least twice. Generally, fiberglass reinforced nylon can achieve a temperature resistance of over 220 degrees Celsius
3. Improve dimensional stability and reduce shrinkage rate;
4. Reduce warping deformation;
5. Reduce creep;
6. Due to the candle core effect, the flame retardant performance will interfere with the flame retardant system and affect the flame retardant effect;
7. Reduce surface glossiness;
8. Increase moisture absorption;
9. Fiberglass treatment: The length of fiberglass directly affects the brittleness of the material. If fiberglass is not properly treated, short fibers will reduce impact strength, while long fibers will increase impact strength. To prevent a significant decrease in material brittleness, it is necessary to choose a certain length of fiberglass.
Conclusion: To achieve good impact strength, surface treatment and length of fiberglass are crucial!
Fiber content: The fiber content of a product is also a key issue. China generally adopts integer contents such as 10%, 15%, 20%, 25%, and 30%, while foreign countries determine the content of fiberglass based on the purpose of the product. Glass fiber is a very good substitute material for metal materials. With the rapid development of the market economy, glass fiber has become an essential raw material in industries such as construction, transportation, electronics, electrical, chemical, metallurgy, environmental protection, and national defense. Due to its widespread application in multiple fields, glass fiber is increasingly receiving attention from people. The major global producers and consumers of fiberglass are developed countries such as the United States, Europe, and Japan, with a relatively high per capita consumption of fiberglass. Europe remains the largest region for glass fiber consumption, accounting for 35% of the global total usage.
Since 2008, glass fiber enterprises around the world have become more cautious about expanding production plans, and the growth of global glass fiber production capacity has been slow. In 2010, the global continuous glass fiber production capacity was 4.715 million tons, and it is expected to be 5.3 million tons this year. After years of development, China's fiberglass enterprises have achieved upstream product quality, and the proportion of deep processed products has been increasing year by year. The gross profit margin of leading enterprises in China's fiberglass industry ranges from 25% to 35%, significantly higher than the 10% gross profit margin of foreign giants. The global fiberglass industry has long been an oligopoly. As a new force, China, with an average annual production capacity growth rate of over 20% in recent years, is expected to occupy more than 60% of the global market share this year, becoming a new oligopoly in the international fiberglass market.
The rapid development of China's fiberglass industry in recent years has been driven by both domestic and foreign markets. The expansion of the international market is driven by both the growth of total demand and the development space left for domestic enterprises in the international market after international enterprises withdrew from the industry due to low profit margins in the early stage; The growth of the domestic market comes from the rapid development of downstream consumer industries. After more than 50 years of development, Chinese fiberglass has already reached a considerable scale.
Compared with international standards, China's fiberglass products have fewer varieties and narrow application ranges. But these situations also indicate from another perspective that there is still a large amount of untapped market space in China's fiberglass industry, especially in some application fields, where many segmented markets have not even been developed. In the last few years of the 20th century, guided by the market-oriented development strategy of the National Building Materials Administration, the fiberglass industry saw gratifying changes in both overall production and various advanced fiberglass products. China's fiberglass industry started in the early stages of reform and opening up, and in 20 years, it has become the second largest producer of fiberglass products in the world, with a significantly faster growth rate in production than in the world. In 1985, China's fiberglass production was only a meager 71000 tons, barely accounting for 1/20 of the world's fiberglass production. However, after entering the 1990s, the fiberglass industry made rapid progress. Despite the stagnation and bottleneck in the world's fiberglass production from 2001 to 2003, China's fiberglass production still maintained a rapid growth momentum. In 2003, the annual production of 473000 tons had almost reached 1/5 of the world's fiberglass production, exceeding the goal of 380000 to 400000 tons of fiberglass production set in the national "15th Five Year Plan". China's fiberglass industry belongs to an outward oriented structure, with imports and exports showing a two-way growth trend, especially with the vigorous development of the fiberglass industry, imports and exports have maintained high-speed growth. In 2003, the export volume had reached 59.1% of the total fiberglass production. The high import and export ratio indicates that China's fiberglass industry has fully integrated with the international fiberglass market, and the improvement in product output and quality has greatly enhanced the international market competitiveness of China's fiberglass industry. On the other hand, the sustained and steady development of China's economy has also increased the domestic demand for advanced fiberglass products from abroad. This healthy extroverted structure leads to a virtuous cycle. China's fiberglass industry has always been in a deficit state in the past, but the gap between exports and imports has been narrowing. By the first half of 2004, it achieved a trade surplus of 59.1755 million US dollars, completely reversing the situation where imports exceeded exports in the entire industry
In 2006, the country produced a total of 1.1607 million tons of fiberglass yarn, a year-on-year increase of 22.18%. Among them, the output of the tank kiln is 891200 tons, accounting for 76.79% of the total production. The sales rate of fiberglass industrial products was 99.5%, an increase of 2.8 percentage points compared to the same period in 2005, and inventory levels decreased. In 2006, the main business cost of the enterprise reached 23.744 billion yuan, a year-on-year increase of 30.84%. Enterprises have overcome the impact of rising raw material prices and achieved a new high in profit levels. In 2006, the industry achieved a total profit of 2.566 billion yuan, a year-on-year increase of 39.65%; Realized a total profit and tax of 3.685 billion yuan, a year-on-year increase of 43.53%. In 2006, China's fiberglass industry earned 1.18 billion US dollars in foreign exchange through exports, achieving a trade surplus of 451 million US dollars, and exporting a total of 7901 million tons of fiberglass and its products, a year-on-year increase of 38.9%.
From January to November 2007, China's fiberglass and product manufacturing industry achieved a total industrial output value of 37624527 thousand yuan, an increase of 38.07% compared to the same period last year; Accumulated sales revenue of 36565839 thousand yuan, an increase of 38.22% compared to the same period last year; The cumulative total profit achieved was 3541052 thousand yuan, an increase of 51.08% compared to the same period last year.
Due to the impact of the international financial crisis in 2008, the export situation of China's fiberglass was very severe. In the current period of sluggish international economic situation and oversupply, it is necessary to accelerate the development and application of downstream products in the fiberglass industry to comply with current national policies. Pay attention to the domestic demand for fiberglass yarn, expand domestic demand, and maintain sustained domestic economic development.
In December 2011, China produced 310000 tons of fiberglass yarn, a year-on-year increase of 15.28%. From January to December 2011, the national production of fiberglass reached 3.72 million tons, a year-on-year increase of 17.95%.
From the production of various provinces and cities, from January to December 2011, the production of glass fiber in Shandong reached 1.25 million tons, a year-on-year increase of 18.79%, accounting for 33.67% of the total national production. Following closely behind are Zhejiang, Chongqing, and Sichuan, accounting for 19.95%, 11.49%, and 9.66% of the total production, respectively.
Because of this, excellent domestic glass fiber industry production enterprises are increasingly valuing research on the industry market, especially in-depth research on the development environment of enterprises and changes in customer demand trends. A large number of excellent domestic glass fiber enterprises are rapidly rising and gradually becoming leaders in the glass fiber industry!
In the long run, the strengthening and renovation of infrastructure in the Middle East and Asia Pacific have led to a significant increase in demand for fiberglass. With the continuous growth of global demand for fiberglass in areas such as modified plastics, sports equipment, and aerospace, the outlook for the fiberglass industry remains optimistic. In addition, the application field of fiberglass has expanded to the wind power market, which may be a bright spot for the future development of fiberglass. The energy crisis has prompted countries to seek new energy sources, and wind energy has become a focus of attention today. China has also begun to increase investment in the field of wind power. By 2020, China will invest 350 billion yuan in the field of wind power generation, of which about 20% (or 70 billion yuan) will require the use of fiberglass (such as wind turbine blades). This is a large market for Chinese fiberglass enterprises.