Treasure material delayed by the name - fiberglass
What is FRP? When hearing “Glass Steel” for the first time, many people are misled by the name, thinking that it is a kind of steel, or a combination of glass and steel. But in fact, FRP has nothing to do with steel, its essence is a fiber reinforced plastic, the scientific name is glass fiber reinforced plastic.
From the composition point of view, FRP is mainly composed of two parts: one is a synthetic resin, as a bonding agent matrix, just like the concrete in the cement, to play the role of adhesion and fixation; the second is the glass fiber and its products, as a reinforcing material, like the concrete in the reinforcing bars, to assume the main task of force, greatly enhancing the strength of the material. Just as in the construction of a house, the reinforcement provides a solid support structure, the cement binds the reinforcement together to form a strong structure. In FRP, the glass fibers give the material its strength and rigidity, while the synthetic resin ensures that the connections between the glass fibers are strong, giving the overall material good formability and stability.
Depending on the resin matrix material used, FRP can be subdivided into polyester FRP, epoxy FRP, phenolic FRP, and so on. Different types of resins give FRP different characteristics to meet diversified application needs.
Characteristics of FRP
The reason why FRP can be widely used in many fields cannot be separated from its series of excellent characteristics.
â–ºLight weight and high strength
The density of FRP is usually between 1.4 - 2.1g/cm³, which is about 1/4 - 1/5 of the density of steel, but its specific strength (the ratio of strength to density) is very high, even exceeding some special alloy steels. In the aerospace field, for example, the wings, fuselage and other parts of the aircraft if the use of glass fiber reinforced plastic manufacturing, can effectively reduce the weight of the aircraft, in the case of consuming the same fuel, can fly a longer distance, improve flight efficiency and range. In the automotive industry, the use of fiberglass reinforced plastic production of automotive shells, interiors and other components, not only can reduce body weight, improve fuel economy, but also enhance the handling performance of the vehicle.
â–ºStrong corrosion resistance
FRP has excellent resistance to a variety of chemicals, whether it is acid, alkali, salt and other corrosive media, or in the humidity, the ocean and other harsh environments, can maintain stable performance, not easy to be corroded. In the chemical industry, many storage and transportation of corrosive liquids such as pipelines, tanks and other equipment are made of FRP, greatly extending the service life of the equipment, reducing maintenance costs and safety hazards due to equipment corrosion and leakage. In the marine environment, glass fiber reinforced plastic fishing boats can resist the erosion of seawater for a long time, compared with the traditional wooden or steel fishing boats, no need for frequent anticorrosion treatment, reducing maintenance costs and improving operational efficiency.
â–º Good insulation
Fiberglass reinforced plastic is an excellent insulating material, its dielectric properties are good, in the high-frequency electric field can still maintain stable insulating properties. This characteristic makes it widely used in the electrical industry, such as the production of cable protection pipe, can effectively protect the cable from the external environment, to ensure the safety and stability of power transmission; in electrical equipment, FRP is often used to manufacture insulating parts, prevent current leakage, to protect the normal operation of equipment and personnel safety.
â–º Molding flexibility
The molding process of FRP is rich and diverse, and the common ones are hand-layup molding, winding molding, pressing molding, pultrusion molding and so on. Hand-layered molding process is simple, without complex equipment, suitable for small batch, personalized product production, such as some artistic sculpture, small ships, etc.; winding molding is commonly used in the manufacture of cylindrical or tubular products, such as pipelines, pressure vessels, etc., by controlling the winding angle of fibers and the number of layers, you can accurately adjust the performance of the product; molding is suitable for the production of high dimensional accuracy, batch size products, such as automotive components, electrical enclosures, etc.; pulling the extrusion of the product. Molding is suitable for the production of products with high dimensional accuracy and large batch size, such as automobile parts, electrical appliance shells, etc.; pultrusion molding is able to continuously produce products with fixed cross-sectional shapes, such as profiles, rods, etc., with high productivity. These diversified molding processes enable FRP to produce products of various shapes and properties according to different needs.
Production process
•Hand lay-up molding
Hand lay-up molding is a traditional and basic FRP molding process, which mainly relies on manual operation. First of all, the mold should be carefully treated to ensure that the surface of the mold is clean, flat and free of oil, which is the basis for ensuring the quality of the products. Then, the mold surface is evenly coated with mold release agent, which is convenient for the subsequent demolding of products. Next, according to the design requirements, the reinforcing materials such as glass fiber fabric or short-cut mat are cut into suitable shapes and sizes. In the lay-up process, first brush a layer of prepared resin on the mold, then lay the reinforcing material on the resin, use tools such as brushes or rollers to fully saturate the resin, and carefully remove air bubbles to ensure that the resin and reinforcing material are closely combined. The laying operation is repeated in this way until the designed thickness is reached. Finally, the resin is allowed to cure at room temperature or under appropriate heating conditions. After curing is complete, the product is carefully removed from the mold and the necessary post-processing such as sanding, trimming, surface coating, etc. is performed.
The reason why the hand lay-up molding process is suitable for the production of small quantities of large and complex products is that it is highly flexible. No need for large and complex equipment, only simple tools can complete the operation, greatly reducing production costs and equipment investment. For large and complex products, such as large ships, sculpture, etc., hand lay-up molding can be freely lay-up and modeling according to the shape characteristics of the product to meet the diversified design needs of the product . However, it also has some disadvantages, such as low production efficiency, high labor intensity, product quality is affected by the operator's technical level and work attitude.
• Winding molding
Winding molding is to wind the continuous fiber (or cloth tape, pre-impregnated yarn) soaked with resin glue to the core mold according to a certain rule, and then obtain the products after curing and demolding. According to the different physicochemical state of the resin matrix during fiber winding, it can be divided into three processes: dry winding, wet winding and semi-dry winding.
Dry winding uses prepreg yarns or tapes that have undergone prepreg treatment, which are heated and softened to a viscous flow state on the winding machine and then wound onto the core mold. This method can strictly control the resin content and the quality of prepreg yarn, so as to accurately control the product quality, with high production efficiency, the winding speed can reach 100 - 200m/min, and the winding machine is clean, with good labor hygiene conditions. However, the equipment is expensive and needs to increase the prepreg yarn manufacturing equipment, which is a big investment, and the interlayer shear strength of the products is low.
Wet winding is to wind the fiber bundle (yarn tape) directly onto the mandrel under tension control after impregnation. The cost is 40% lower than that of dry winding, and the product is airtight because the winding tension enables the excess resin glue to squeeze out the air bubbles and fill up the voids, and the fibers are aligned in a better parallelism, and at the same time the resin glue on the fibers reduces the abrasion of the fibers, and the production efficiency is higher (up to 200m/min). However, wet winding has the problems of high waste of resin, poor operating environment, difficult to control the glue content and quality of the finished product, and fewer choices of resin.
Semi-dry winding is to add a set of drying equipment to remove solvents from the impregnated yarns after fiber impregnation and on the way to winding to the mandrel. It not only eliminates the pre-impregnation process and equipment, but also reduces the bubble content in the product.
Wrap-around molding has a wide range of applications in the production of pipes and tanks. In petrochemical industry, many pipelines for conveying corrosive liquids and storage tanks for storing liquids are made of FRP by winding molding. By controlling the angle of fiber winding and the number of layers, the pipes and tanks can be made in different directions to obtain the appropriate strength to meet different requirements. Compared with traditional metal pipes and tanks, FRP pipes and tanks have the advantages of light weight, corrosion resistance, easy installation and so on.
• Pultrusion molding
Pultrusion molding refers to the glass fiber roving or its fabrics in the external traction (external pulling and extrusion molding), through the dip, extrusion molding, heating and curing, fixed length cutting, continuous production of unlimited length of FRP linear products of a method.
Typical pultrusion speeds for pultrusion molding are 0.5 - 2m/min, which is extremely efficient and suitable for the mass production of long products. The resin content can be precisely controlled during the production process, the main use of twist-free roving reinforcement results in low raw material costs, and a variety of reinforcement materials can be used in combination to flexibly adjust the mechanical properties of the product. The fiber content of pultruded products can be as high as 80%, and the impregnation is carried out under tension, which can give full play to the mechanical properties of continuous fibers and make the products of high strength. At the same time, the utilization rate of raw materials in more than 95%, scrap rate is low, the longitudinal and transverse strength of the products can also be adjusted according to the needs of different mechanical properties of products to meet the use of the requirements.
Because of these characteristics of pultrusion molding, it has obvious advantages in the manufacture of profiles. Commonly, such as doors and windows in the construction industry, various structural profiles in industry (such as I-beam, channel, square profiles, etc.) and some special-purpose rods, tubes, etc., can be efficiently produced by pultrusion molding process. These pultruded profiles have lightweight, high strength, corrosion resistance, insulation and other excellent properties, gradually in various fields to replace the traditional metal profiles.
• Molding
Molding is a certain amount of molding materials (such as premixed materials, pre-pregs, etc.) into the metal mold, at a certain temperature and pressure to make the material filled with mold cavity, and chemical reaction and curing process.
First of all, according to the shape and size of the product design and manufacture of molds, molds are usually composed of upper and lower molds, the precision requirements are high. The prepared molded material is evenly placed in the mold cavity, after the mold is closed, a certain pressure is applied by the press, so that the molded material flows in the mold and fills the entire cavity, and at the same time, under the action of the heating system, the temperature of the molded material is gradually increased, and the resin undergoes a cross-linking reaction, resulting in the curing and molding of the product. After curing, the mold is opened and the product is removed.
Molding is suitable for mass production of high-precision products, because under the limitations of the mold, the dimensional accuracy of the product can be well guaranteed, and the surface quality is also high. In the field of automobile manufacturing, many automobile parts, such as bumpers, interior parts, etc., are made of molded FRP, which can not only meet the requirements of precision and appearance of the products, but also make use of the lightweight and high-strength characteristics of FRP to reduce the weight of automobiles and improve fuel economy. In the electrical and electronic industry, some electrical appliances shells are also produced through the molding process, good insulation properties and dimensional stability, to ensure the safe operation of electrical equipment and aesthetic.
Hongpeng has a variety of composite material molding processes such as hand-lay-up molding, winding molding, molding, pultrusion molding, injection molding and so on, to meet the needs of different customers' purchasing!
Application Areas
♦Construction industry
In the construction industry, FRP can be found everywhere. In terms of building structure, FRP profiles are often used to build lightweight building structures, such as some temporary buildings, exhibition hall structures of exhibition halls, etc.. Due to its light weight and high strength, it not only reduces the weight of the building structure and the bearing pressure of the foundation, but also makes the construction process more convenient and efficient, and can shorten the construction period.
In the field of doors and windows manufacturing, FRP doors and windows are gradually favored by the market. Compared with traditional aluminum alloy doors and windows and plastic steel doors and windows, FRP doors and windows have better thermal insulation properties, which can effectively reduce the transfer of indoor and outdoor heat, reduce the energy consumption of air conditioning and heating equipment, and achieve the energy-saving goals of the building. At the same time, its strong corrosion resistance, even in the humidity, acid rain and other harsh environments are not easy to rust and corrosion, long service life, reducing the cost of maintenance and replacement.
FRP is also widely used in the production of sanitary ware, such as bathtubs, washbasins and toilets. It can be molded through the molding process to produce a variety of shapes and sizes of sanitary ware, the surface is smooth and easy to clean, and has good thermal insulation properties, to provide users with a more comfortable experience.
♦ Transportation
In the automobile industry, fiberglass reinforced plastic (FRP) is widely used in the manufacture of automobile parts. The bumper of the car is made of FRP, which can not only reduce its own weight and energy consumption of the whole car, but also play a good buffer role in the collision and improve the safety performance of the vehicle. The use of FRP in the interior parts of automobiles, such as instrument panels, seat shells, etc., can realize the diversification of shapes, meet the demand of consumers for personalized interior, and also reduce the weight of the interior.
In the field of shipbuilding, FRP is one of the ideal materials for manufacturing ship hulls. FRP hulls are characterized by light weight, high strength and corrosion resistance, which can increase the sailing speed of ships, reduce fuel consumption, and reduce the frequent maintenance work required due to seawater corrosion. Many small yachts, fishing boats and some inland waterway transportation vessels are made of FRP, which improves the performance and economic benefits of the vessels.
In railroad transportation, FRP also has certain applications. For example, the interior parts of some railroad vehicles, sound insulation boards, etc. made of FRP, the use of its good insulation, sound insulation and lightweight characteristics, to provide passengers with a quieter, more comfortable riding environment.
♦Chemical industry
In chemical production, many media are highly corrosive, and the corrosion resistance of storage and transportation equipment is highly required. Glass fiber reinforced plastic (FRP) corrosion-resistant pipes and storage tanks have become one of the preferred equipment in the chemical industry. These pipes and tanks can withstand a variety of acids, alkalis, salts and other corrosive media erosion, to ensure the safe and stable operation of the chemical production process. Compared with traditional metal pipes and tanks, FRP equipment has a longer service life and lower maintenance costs, effectively reducing the operating costs of chemical enterprises. At the same time, its good sealing performance can also prevent the medium leakage, reduce the pollution of the environment.
♦Other fields
In the electrical industry, fiberglass reinforced plastic is widely used in the production of insulating parts, such as insulators, insulating bushings and so on, by virtue of its good insulating properties. These parts play a vital role in the power system, to ensure the normal transmission of current, to ensure the safe operation of power equipment.
In the field of sporting goods, FRP also has many application cases. For example, the tennis racket and badminton racket made of FRP are characterized by light weight and high strength, which can make the athletes hit the ball more easily and improve the speed and power of hitting the ball. Some water sports equipment, such as rowing boats, kayaks, etc., the use of fiberglass material production, not only reduces the weight of the equipment, improve the speed of movement, but also enhance the durability of the equipment .
In the future, the FRP industry will move towards environmental protection, intelligence, high performance and other directions. In terms of environmental protection, with the global environmental awareness and increasingly strict environmental regulations, the FRP industry will pay more attention to the environmental protection of raw materials and the production process of energy saving and emission reduction. R & D and the use of biodegradable resins, recycling waste FRP and other environmental initiatives will become an important direction for the development of the industry .