Glass fiber is an inorganic non-metallic material with excellent properties.
The original English name is: glass fiber or fiberglass.
The components are silica, alumina, calcium oxide, boron oxide, magnesium oxide, sodium oxide and so on.
It is made from glass balls or waste glass through high temperature melting, drawing, winding, weaving and other processes.
Finally, the formation of various types of products, glass fiber monofilament diameter from a few microns to more than 20 microns, equivalent to a hair 1/20-1/5, each bundle of fibers are hundreds or even thousands of monofilaments composed of materials, usually as a compound material in the reinforcing materials, electrical insulating materials and insulation materials, insulation materials, circuit boards, etc., are widely used in various fields of the national economy.
Characteristics of Glass Fiber:
Glass is generally regarded as a hard and fragile material, which is not suitable as a structural material. However, if it is drawn into a filament, its strength is greatly increased and it has flexibility, so it can finally become a good structural material after it is given a shape with resin.
The strength of glass fiber increases as its diameter decreases.
As a reinforcing material, glass fibers have the following characteristics, which make the use of glass fibers far more extensive than other types of fibers, and the development of the speed is also far ahead of its characteristics are listed as follows:
(1) High tensile strength, elongation is small (3%).
(2) High coefficient of elasticity, good rigidity.
(3) Elongation within the limits of elasticity and high tensile strength, so absorb impact energy.
(4) Inorganic fiber, non-combustible, good chemical resistance.
(5) Low water absorption.
(6) Good stability and heat resistance.
(7) Good processability, can be made into strands, bundles, felts, fabrics and other different forms of products.
(8) Transparent and translucent.
(9) The development of surface treatment agent with good adhesion to resin is completed.
(10) Inexpensive.
Classification of glass fibers:
Glass fibers can be divided into continuous fibers, fixed-length fibers and glass wool according to the form and length; according to the glass composition, it can be divided into alkali-free, chemical-resistant, high-alkali, medium-alkali, high-strength, high modulus of elasticity, and alkali glass fibers and so on.
The main raw materials for the production of glass fibers are: quartz sand, alumina and chlorite, limestone, dolomite, boric acid, soda ash, manganese, fluorite and so on.
Production methods are roughly divided into two categories: a class of molten glass directly into fibers; a class of molten glass first made of glass balls or rods with a diameter of 20mm, and then in a variety of ways to heat remelted into very fine fibers with a diameter of 3 ~ 80μm.
Through the platinum alloy plate to mechanical drawing method of infinite length of the fiber, known as continuous glass fiber, commonly known as long fiber.
Non-continuous fibers made by rollers or airflow are called fixed-length glass fibers, commonly known as short fibers.
By centrifugal force or high-speed airflow made of fine, short, flocculent fibers, known as glass wool.
Glass fiber can be processed into a variety of forms of products, such as yarn, untwisted roving, short cut filaments, cloth, tapes, mats, boards, tubes and so on.
Glass fibers are classified into different levels according to their composition, properties and uses.
According to the standard level of regulations (see table), E-grade glass fibers are the most common, widely used in electrical insulation materials; S-class special fibers, although the yield is small, but very important, because of the super-strength, mainly used for military defense, such as bullet-proof boxes, etc.; C-grade is more chemically resistant than the E-grade, used in the battery isolation panels, chemical filters; A-grade for the alkaline glass fibers for the production of reinforcing materials.
Glass fiber - the main components of its main components are silica, alumina, calcium oxide, boron oxide, magnesium oxide, sodium oxide, etc., according to the amount of alkali content in the glass can be divided into non-alkali glass fibers (sodium oxide 0% to 2%, is an aluminum borosilicate glass), medium-alkali glass fibers (sodium oxide 8% to 12%, is a boron-containing or boron free soda-lime silicate glass) and high-alkali glass fibers (more than 13%, is a sodium-calcium glass), and high alkali glass fibers (more than 13%, is a sodium-calcium glass). 13% or more sodium oxide, sodium calcium silicate glass).
Glass fiber - characteristics, raw materials and their applications of glass fibers than organic fibers, high temperature, non-combustible, corrosion resistance, thermal and acoustic insulation (especially glass wool), high tensile strength, good electrical insulation (such as non-alkali glass fiber).
But brittle, poor abrasion resistance.
Glass fiber is mainly used as electrical insulation materials, industrial filtration materials, corrosion, moisture, heat insulation, sound insulation, shock absorption materials.
It can also be used as a reinforcing material to make reinforced plastics (see color chart) or reinforced rubber, reinforced gypsum and reinforced cement products.
Glass fiber coated with organic materials can improve its flexibility, used to make packaging cloth, window screen, wall cloth, cover cloth, protective clothing and adiabatic, sound insulation materials.
The glass used in the production of glass fiber is different from the glass of other glass products.
At present, the international commercialization of fiber glass composition is as follows:
1, E-glass, also known as alkali-free glass, is a borosilicate glass.
At present, it is the most widely used glass fiber with a glass component, with good electrical insulation and mechanical properties, widely used in the production of electrical insulation glass fiber, also used in large quantities for the production of glass fibers for glass fiber reinforced plastic, and its shortcomings are susceptible to inorganic acid erosion, so it is not suitable for use in an acidic environment.
2, C-glass, also known as medium alkali glass, which is characterized by chemical resistance, especially acid resistance is better than alkali glass, but the electrical properties of poor mechanical strength is lower than the alkali glass fibers 10% to 20%, usually foreign medium alkali glass fibers contain a certain amount of diboron trioxide, and China's medium alkali glass fibers are completely boron free.
In foreign countries, medium alkali glass fiber is only used for the production of corrosion-resistant glass fiber products, such as for the production of fiberglass surface mat, etc., is also used to enhance the asphalt roofing materials, but in our country, medium alkali glass fiber glass fiber to occupy a large part of the production (60%), widely used in fiberglass reinforcement as well as filtration fabrics, fabrics, such as wrapping the production of because of the price is lower than the non-alkali glass fiber and have a strong competitiveness. Strong competitiveness.
3, high-strength glass fiber is characterized by high strength, high modulus, its single-fiber tensile strength of 2800MPa, than the tensile strength of alkali-free glass fiber about 25% higher than the modulus of elasticity of 86,000MPa, higher than the strength of E-glass fiber.
The FRP products produced with them are mostly used in military, space, bulletproof armor and sports equipment.
But because of the high price, currently in the civilian side can not be promoted, the world production is only a few thousand tons or so.
4, AR glass fiber, also known as alkali-resistant glass fiber, mainly developed to enhance the cement.
5, A glass, also known as high alkali glass, is a typical sodium silicate glass, due to poor water resistance, rarely used in the production of glass fiber.
6, E-CR glass is an improved boron-free alkali-free glass for the production of acid-resistant and water-resistant glass fibers, its water resistance than non-alkali glass fiber to improve the 7 to 8 times, acid resistance than the medium-alkali glass fiber is also superior to a lot of new varieties of underground pipelines, tanks and other development.
7, D glass, also known as low dielectric glass, is used to produce low dielectric glass fiber with good dielectric strength.
In addition to the above glass fiber components, in recent years, there is also a new alkali-free glass fiber, which does not contain boron, thereby reducing environmental pollution, but its electrical insulation properties and mechanical properties are similar to the traditional E glass.
In addition, there is a double glass composition of glass fibers, has been used in the production of glass wool, allegedly in the fiberglass reinforced materials also have the potential.
There are also fluorine-free glass fibers, which are improved alkali-free glass fibers developed for environmental requirements.
Varieties and uses of glass fiber products
1, no-twist roving
No-twist roving is made of parallel filaments or parallel monofilaments clustered into a.
No-twist roving is made of parallel filaments or parallel monofilaments clustered together.
Twist-free roving can be divided into: non-alkali glass twist-free roving and medium alkali glass twist-free roving according to the glass composition.
The diameter of glass fibers used in the production of glass roving ranges from 12 to 23 μm.
Twist-free roving is available in sizes ranging from 150 to 9600 (tex).
Twist-free roving can be used directly in certain composite process molding methods, such as winding and pultrusion, and can also be woven into twist-free roving fabrics because of its uniform tension, and in some applications, twist-free roving is further short-cut.
(1) spray twisted roving suitable for fiberglass injection molding use of twisted roving to have the following properties: ① good cutting, in the continuous high-speed cutting of static electricity produced by less; ② twisted roving cut and dispersed into the original filament of the efficiency of the high, that is, the rate of bunches of high, usually more than 90%; ③ short-cutting of the original filament has an excellent overmolding, can be covered in the mold of all corners; ④ The resin soaks in fast, easy to be rolled flat and easy to drive away air bubbles; ⑤ raw silk cylinder annealing performance is good, uniform yarn density, suitable for a variety of spray gun and fiber delivery system.
No-twist roving for spraying is made of multi-stranded filaments, each strand of which contains 200 glass fiber monofilaments.
(2) SMC twistless roving SMC is sheet molding compound, mainly used for pressing automobile parts, bathtubs, water tank plates, purification tanks, various seats and so on.
SMC twistless roving in the manufacture of SMC sheet to be cut into lin (25mm) length, dispersed in the resin paste, so the requirements for SMC twistless roving is a good short cut, less hairy filament, excellent antistatic properties, in the cutting of the short cut filament will not adhere to the knife roller.
For colored SMC, the twistless roving has to be impregnated by the resin in a paste with high pigment content.
Typically, SMC twistless roving is 2400 tex, and in a few cases 4800 tex.
(3) Winding with twisted roving is used to manufacture FRP pipes and tanks of various caliber.
The number of twisted roving for winding ranges from 1200 to 9600, and large pipes and tanks tend to be wound with direct twisted roving, such as 4800tex direct twisted roving.
The requirements for twisted roving for winding are as follows: ① good tape formation, flat tape; ② good unwinding of twisted roving, no looping when unwinding from the cylinder, no formation of "bird's nest" messy filaments; ③ even tension, no overhanging phenomenon; ④ even line density, generally less than ±7%; ⑤ twisted roving penetration is good, easy to pass from the resin tanks for the resin to be wetted and infiltrated.
(4) Twist-free roving for pultrusion Pultrusion is used to manufacture a variety of profiles with consistent cross-section, which is characterized by high glass fiber content and high unidirectional strength.
Twist-free roving for pultrusion can be either multi-stranded filaments merged or direct twist-free roving, with densities ranging from No. 1100 to No. 4400.
The performance requirements are largely the same as for twisted roving.
(5) Weaving twisted roving An important use of twisted roving is to weave chevron or unidirectional twisted roving fabrics of various thicknesses, which are mostly used in hand-lay-up FRP molding processes.
Twisted roving for strong fabrication has the following requirements: (1) good abrasion resistance; (2) good tape formation; (3) twisted roving for weaving needs to be forced drying before weaving; (4) twisted roving tension uniformity, the degree of drape should be in line with certain standards; (5) twisted roving good annealing; (6) twisted roving good permeability.
(6) Pre-form twisted roving In the pre-form process, twisted roving is short-cut and sprayed on a predefined shape of the network, while spraying a small amount of resin to make the fiber network fixed formation, and then move the formed fiber network into a metal mold, injected with resin and hot-pressing molding, that is, the product.
The performance requirements of twisted roving for this process are basically the same as those of sprayed twisted roving.
2, twisted roving fabric (chevron)
Chevron is a twisted roving plain fabric, is an important substrate for hand lay-up FRP.
The strength of chevron fabric is mainly in the direction of warp and weft of the fabric, for the requirement of high strength in warp or weft direction, it can also be woven into unidirectional chevron fabric, it can be arranged in the direction of warp or weft more twisted roving.
The quality requirements of the other side of the checkerboard fabric are as follows: ① fabric uniformity, straight edges, cloth surface flat mat, no stains, hair, creases, wrinkles, etc.; ② warp, weft density, the area of the weight, fabric width and roll length are in line with the standard; ③ coiled in a solid core, winding neat; ④ rapid, good resin permeability; ⑤ fabric made of laminated materials, dry and wet state mechanical strength should meet the requirements.
The composite material formed by laying with chevron fabric is characterized by low interlaminar shear strength, poor compressive and fatigue strength.
3, glass fiber mats
(1) short cut wire mats will be cut glass raw silk (sometimes also used twisted roving) cut into 50mm long, will be randomly but evenly spread on the mesh belt, followed by the application of emulsion binder or sprinkled with powdered knots bonded to short cut wire mats after heating and curing.
Short-cut felts are mainly used in hand-lay-up, continuous sheet and counter molding and SMC processes.
The quality requirements of the short-cut filament felt are as follows: ① uniform quality of the area along the width direction; ② uniform distribution of short-cut filaments in the felt surface, no large pore formation, and uniform distribution of binder; ③ moderate dry felt strength; ④ excellent resin infiltration and permeability.
(2) Continuous filament felt will be formed in the process of drawing glass filament or continuous filament from the original barrel of the retreat out of the zigzag laying in the continuous moving mesh belt, by the powder binder bonding and become.
The fibers in continuous glass fiber mat are continuous, so its reinforcing effect on composite materials is better than that of short-cut mat.
Mainly used in pultrusion, RTM method, pressure bag method and glass mat reinforced thermoplastic (GMT) and other processes.
(3) surface felt FRP products usually need to form a rich resin layer, which is generally realized with medium alkali glass surface felt.
This kind of felt because of the use of medium alkali glass (C) made, so the chemical resistance of FRP, especially acid resistance, at the same time because of the felt is thin, glass fiber diameter of the reason, but also can absorb more resin to form a resin-rich layer, cover up the glass fiber reinforced material (such as chevron) of the texture, to play the role of surface modification.
(4) Needled Felt Needled Felt or divided into short-cut fiber needle felt and continuous filament needle felt.
Short-cut fiber needle felt is a glass fiber roving short cut into 50mm, randomly laid on the substrate placed on the conveyor belt in advance, and then with a barbed needle needling, the needle will be short-cut fibers into the substrate, and the barb will be some of the fibers up to the formation of three-dimensional structure.
The substrate used can be a thin fabric of glass fibers or other fibers, and this needle felting has a plush feel.
Its main uses include as a thermal and acoustic insulation materials, heat lining materials, filtering materials, can also be used in the production of glass fiber reinforced plastic (FRP), but the FRP strength of the system is low, the scope of use is limited.
Another type of continuous filament needled felt, is the continuous glass filament with throwing device randomly thrown on the continuous mesh belt, needle plate needling, the formation of fibers linked to each other in the three-dimensional structure of the felt.
This kind of felt is mainly used in the production of glass fiber reinforced thermoplastic stampable sheet.
(5) sewing felt short-cut glass fibers from 50mm or even 60cm long can be sewing machine will be sewn into a short-cut fiber or long-fiber felt, the former can be used in a number of applications instead of the traditional binder bonded short-cut felt, the latter to a certain extent instead of the continuous filament felt.
They have the *** same advantage of being binder free, avoiding pollution in the production process, as well as good impregnation properties and lower prices.
4, short-cut raw silk and ground fiber
(1) short-cut raw silk short-cut raw silk dry short-cut raw silk and wet short-cut raw silk.
The former is used in the production of reinforced plastics, while the latter is used in papermaking.
The cut wires used for FRP are divided into two categories: reinforced thermosetting resin (BMC) cut wires and reinforced thermoplastic resin cut wires.
Requirements for the reinforced thermoplastic with chopped filaments is the use of alkali-free glass fibers, high strength and good electrical insulation, chopped filaments with good clustering, good fluidity, high whiteness.
Enhancement of thermosetting plastics short cut raw wire required to bundle good, easy for the resin quickly soaked, with good mechanical strength and electrical properties.
(2) Ground fiber Ground fiber by the hammer mill or ball mill to grind the short-cut fiber into.
Ground fiber is mainly used as a reinforcing material in the enhanced reaction injection process (RRIM), in the manufacture of cast products, molds and other products used as a filler for the resin to improve the phenomenon of surface cracks, reduce molding shrinkage, can also be used as a reinforcing material.
5, glass fiber fabrics
The following is a variety of glass fiber fabrics woven with glass fiber yarn.
(1) glass cloth China's production of glass cloth, divided into two categories of alkali-free and medium alkali, most of the foreign countries are alkali-free glass cloth.
Glass cloth is mainly used in the production of a variety of electrical insulation laminates, printed circuit boards, a variety of vehicle hulls, storage tanks, boats, molds and so on.
The medium alkali glass cloth is mainly used in the production of plastic-coated packaging cloth, as well as for corrosion-resistant occasions.
The characteristics of the fabric are determined by fiber properties, warp and weft density, yarn structure and weave pattern.
The warp and weft densities are in turn determined by the yarn structure and weave pattern.
The warp and weft density, together with the yarn structure, determines the physical properties of the fabric, such as weight, thickness and breaking strength.
There are five basic weave patterns: plain, twill, satin, rib, and mat.
(2) Glass tape Glass tape is divided into woven edge tape and non-woven edge tape (burlap tape) the main weaving corrosion is plain.
Glass tape is often used in the manufacture of high-strength, good dielectric properties of electrical equipment components.
(3) unidirectional fabrics unidirectional fabrics are a thick warp and fine weft yarns woven into the four warp broken satin or long axis satin fabrics.
It is characterized by high strength in the main warp yarn.
(4) three-dimensional fabrics three-dimensional fabrics are relative to the plane fabrics, its structural characteristics from the one-dimensional two-dimensional development of the three-dimensional, so that the composite material as a reinforcing body has a good integrity and profiling, and greatly improves the composite material's interlaminar shear strength and damage tolerance.
It was developed with the special needs of aerospace, aviation, weapons, ships and other sectors, and now its application has been expanded to automotive, sports equipment, medical equipment and other sectors.
There are five main categories: 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 shape of three-dimensional fabrics are block, columnar, tubular, hollow truncated cone and variable thickness shaped cross-section.
(5) shaped fabrics The shape of the shaped fabrics and the shape of the products it wants to enhance is very similar, must be woven on a special loom.
Symmetrical shaped shaped fabrics are: round cover, cone, cap, dumbbell-shaped fabrics, etc., but also can be made into boxes, hulls and other asymmetric shapes.
(6) groove core fabric groove core fabric is made of two parallel layers of fabric, with longitudinal vertical stripes connected to the fabric composed of the shape of its cross-section can be triangular or rectangular.
(7) glass fiber stitching fabric is also known as knitted felt or knitted felt, which is different from both ordinary fabrics and felt in the usual sense.
The most typical sewn fabric is a layer of warp yarns overlapped with a layer of weft yarns, and the warp and weft yarns are woven together into a fabric by sewing.
The advantages of sewn fabric are as follows: ① it can increase the ultimate tensile strength of FRP laminated products, the strength of delamination under tension and bending strength; ② reduce the weight of FRP products; ③ the surface flattening to make the surface of FRP smooth; ④ simplify the operation of hand-layering to improve the productivity of labor.
This reinforcing material can be used in the pultrusion method of FRP and RTM instead of continuous raw silk felt, but also in the centrifugal method of FRP pipe production to replace the chevron cloth.
6, a combination of glass fiber reinforcing materials
Since the 1970s, the emergence of the short-cut filament mats, continuous filament mats, twisted roving fabrics and twisted roving, etc., in a certain order of combination of reinforcing materials, there are the following:
(1) short-cut filament mats + twisted roving fabrics
(2) short-cut filament mats + twisted roving fabrics + twisted roving fabrics. Short-cut raw silk felt
(3) Short-cut raw silk felt + continuous raw silk felt + short-cut raw silk felt
(4) Short-cut raw silk felt + random untwisted roving
(5) Short-cut raw silk felt or cloth + unidirectional carbon fiber
(6) Short-cut raw silk + surface felt
(7) Glass cloth + unidirectional untwisted roving or glass rods + glass cloth
7, glass fiber wet felt
Glass fiber nonwoven products originated in Europe, and then introduced into the United States, Japan, China and other countries.
China has established several large-scale production lines, the main technology from the German technology such as Changzhou's Zhongxing Tianma, Shaanxi Huate.
At present, the domestic glass fiber wet felt main classifications:
(1) roofing felt for modified bitumen waterproofing roll-roofing, color asphalt shingles and other waterproofing materials substrate;
(2) pipeline felt used for oil, natural gas pipeline cladding, and the combination of asphalt to prevent the corrosion of the underground pipeline;
(3) the surface of the felt fiberglass reinforced plastic products and the surface of the polishing;
(4) veneer felt for walls and ceilings, can prevent cracking of paint, orange peel, mostly used to decorate large conference rooms, high-end hotels;
(5) floor felt used as a substrate for PVC flooring;
(6) carpet felt used as a substrate for carpet tiles;
(7) copper cladding plate felt adhered to copper cladding plate to enhance its punch, drill performance;
(7) copper cladding plate felt adhered to copper cladding plate can enhance its punch, drill performance;
(8) battery separator felt Used as a substrate for aluminum-acid battery separator felt;
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The current situation and prospects of the glass fiber industry
Glass fiber is a very good alternative to metal materials, along with the rapid development of the market economy, glass fiber has become an indispensable raw material for the construction, transportation, electronics, electrical, chemical industry, metallurgy, environmental protection, national defense and other industries. With the rapid development of the market economy, glass fiber has become an indispensable raw material for construction, transportation, electronics, electrical, chemical, metallurgy, environmental protection, national defense, etc.
Because of its wide range of applications in many fields, glass fiber has been receiving increasing attention.
The global glass fiber production and consumption of large countries are mainly the United States, Europe, Japan and other developed countries, the per capita consumption of glass fiber is higher.
Europe is still the largest region of glass fiber consumption, accounting for 35% of the total global consumption.
The rapid development of China's glass fiber industry in recent years, the power from the domestic and foreign markets pull.
The expansion of the international market, both the total demand growth factors, but also from the international enterprises in the early stage due to lower profit margins after the exit of the industry, to the domestic enterprises in the international market to leave the space for development; while the growth of the domestic market, is from the rapid development of downstream consumer industries.
China's glass fiber after more than 50 years of development, has been quite large.
In 2006, the country's cumulative production of glass fiber yarn 1,160,700 tons, an increase of 22.18%.
Among them: pool kiln production 891,200 tons, accounting for 76.79% of the total production.
Glass fiber industry product sales rate of 99.5%, an increase of 2.8 percentage points over the same period in 2005, inventory reduction.
In 2006, the main business costs of enterprises up to 23.744 billion yuan, an increase of 30.84%.
Enterprises to overcome the impact of rising raw material prices, to achieve another record level of profits.
In 2006, the industry realized a total profit of 2.566 billion yuan, an increase of 39.65%; to achieve total profits and taxes of 3.685 billion yuan, an increase of 43.53%.
In 2006, China's glass fiber industry exports 1.18 billion U.S. dollars, to achieve a trade surplus of 451 million U.S. dollars, the cumulative export of glass fibers and products 790,100 tons, an increase of 38.9%.
January-November 2007, China's glass fiber and products manufacturing industry to achieve a cumulative total industrial output value of 37,624,527 thousand yuan, an increase of 38.07% over the same period last year; cumulative sales revenue of 36,565,839 thousand yuan, an increase of 38.22% over the same period last year; cumulative total profit of 3,541,052 thousand yuan, an increase of 51.08% over the same period last year. The cumulative total profit of 3,541,052 thousand yuan, an increase of 51.08% over the same period of the previous year.
2008 by the international financial crisis, China's glass fiber export situation is very serious, in the international economic situation is not good, the current supply exceeds the demand of the period, there is a need to accelerate the development of the application of glass fiber industry downstream products, in order to comply with the current national policy.
Emphasis on domestic demand for glass fiber yarn, expanding domestic demand, to maintain the sustained development of the domestic economy.
In the long run, the Middle East, Asia-Pacific infrastructure strengthening and transformation, the demand for glass fiber increased by a large amount, with the global demand for glass fiber in glass fiber modified plastics, sports equipment, aerospace and other aspects of the growing demand for glass fiber, glass fiber industry outlook remains optimistic.
In addition, the application of glass fiber is extended to the wind power market, which may be a bright spot in the future development of glass fiber.
The energy crisis has prompted countries to seek new energy sources, and wind energy has become a focus of attention in recent years, and China has begun to invest more in the field of wind power.
By 2020, the domestic wind power field will invest 350 billion yuan, of which, 20% (i.e., 70 billion yuan) of the field need to use fiberglass (such as fan blades and other aspects).
This is a big market for Chinese glass fiber companies.
The use of fiberglass cloth: the main purpose of the construction industry.
The building for the exterior wall insulation layer, fiberglass industry is also used in fiberglass cloth.
The main role is to increase the strength.
Fiberglass cloth varieties: fiberglass mesh cloth, fiberglass chevron cloth, fiberglass plain cloth, fiberglass e-cloth.