Due to the different types of resins used, there are polyester fiberglassEpoxy FRPPhenolic FRP.Light and hard, non-conductive, stable performance, high mechanical strength, less recycling, corrosion resistance.It can replace steel to manufacture machine parts, automobile and ship shells.
GlassSteel is known as fiber reinforced plastics, commonly known as FRP (Fiber Reinforced Plastics), that is, fiber reinforced composite plastics.It can be divided into glass fiber reinforced composite plastics (GFRP) and carbon fiber reinforced composite plastics according to the different fibers used（CFRP）, boron fiber reinforced composite plastics, etc.It is based on glass fiber and its products（Glass cloth, tape, felt, yarn, etc.)synthetic resinAs a kind of base materialcompound material。Fiber reinforced compositesIs created byReinforced fibreAnd matrix.The diameter of fiber (or whisker) is very small, generally below 10 μ m, with few and small defects, and the fracture strain is about 30 ‰. It is a brittle material, vulnerable to damage, fracture and corrosion.The strength and modulus of matrix are much lower than that of fiber, but it can withstand large strain, and is often viscoelastic and elastic-plastic. It is a ductile material.
The concept of composite material refers to that one kind of material cannot meet the use requirements and needs to be compounded by two or more kinds of materials to form another kind of material that can meet people's requirements, namely composite material.For example, although a single type of glass fiber has high strength, it is loose between the fibers, which can only withstand tensile force and cannot withstand bending, shear and compressive stress. It is also not easy to make a fixed geometric shape. It is loose software.If usingsynthetic resinThey can be glued together to make various hard products with fixed shapes, which can withstand tensile stress, bending, compression and shear stress.This constitutes a glass fiber reinforced plastic matrix composite.Because its strength is equivalent to steel and contains glass components, it also has the same color, shape, corrosion resistance, electrical insulation, heat insulation and other properties as glass. Like glass, this popular name "glass fiber reinforced plastic" was formed in history, which was originally named by the former minister of the Ministry of Building Materials IndustryLai JifaComrade put forward in 1958 to expand the building materials system to the whole country.Fiberglass means that glass fiber is used as reinforcement and synthetic resin as binderreinforced plastic , foreign nameGlass fiber reinforced plastics。With the development of China's FRP industry, as a plastic based reinforcement material, it has expanded from glass fiber tocarbon fibre、Boron fibre、Aramid fiber, alumina fiber and silicon carbide fiber. Undoubtedly, the reinforced plastics made of these new fibers are of high performanceFiber reinforced compositesIt is impossible to generalize with the common name of fiberglass.Considering the origin and development of history, FRP composites are usually used, which is a comprehensive name.
The relative density is between 1.5 and 2.0, onlycarbon steel1/4~1/5, buttensile strength However, it is close to or even better than carbon steel, and its specific strength can be compared with that of high-grade alloy steel.Therefore, in aviation, rocketSpacecraftHigh pressure vessels and other products that need to reduce self weight have achieved outstanding results.The tensile, bending and compressive strength of some epoxy FRP can reach more than 400Mpa.
Corrosion resistance
FRP is a good corrosion resistant material, which has good resistance to atmosphere, water, acid, alkali, salt of general concentration, as well as a variety of oils and solvents.It has been applied to all aspects of chemical anti-corrosion, and is replacing carbon steel, stainless steel, wood, nonferrous metals, etc.
Good electrical performance
Is excellentInsulating material, used to make insulators.Good dielectric protection at high frequencies.With good microwave transmission, it has been widely used in radar radomes.
Good thermal performance
FRP has low thermal conductivity, 1.25~1.67kJ/(m · h · K) at room temperature, only 1/100~1/1000 of metal, which is excellentThermal insulation material。It is ideal for thermal protection andAblation resistant material, can protectSpacecraftIt is subject to the erosion of high-speed airflow above 2000 ℃.
Good designability
(1) Various structural products can be flexibly designed according to the needs to meet the use requirements, which can make the products have good integrity.
(2) Materials can be fully selected to meet the performance of the product, such as: corrosion resistant, transient high temperature resistant, high strength and good dielectric properties in a certain direction of the product can be designed.
Excellent workmanship
(1) The forming process can be flexibly selected according to the shape, technical requirements, use and quantity of products.
(2) The process is simple, it can be formed at one time, and the economic effect is outstanding, especially for the products with complex shapes and a small number of products that are not easy to form, its process advantages are more prominent.
shortcoming
Low elastic modulus
FRPModulus of elasticityTwice larger than wood, but larger than steel (E=2.1 × 10five）It is 10 times smaller, so it often feels insufficient rigidity and easy to deform in the product structure.
Can be madeshellStructure and sandwich structure can also be made up by means of high modulus fiber or stiffener.
Poor long-term temperature resistance
Generally, FRP cannot be used at high temperature for a long time. The strength of general polyester FRP will decrease significantly when the temperature is above 50 ℃, and it is generally used below 100 ℃;The strength of general-purpose epoxy FRP decreases obviously when the temperature is above 60 ℃.But you can chooseHigh temperature resistant resinIt is possible to keep the long-term working temperature at 200~300 ℃.
Aging phenomenon
Aging is a common defect of plastics, and FRP is no exception. Under the action of ultraviolet radiation, wind, sand, rain, snow, chemical media, mechanical stress, etc., it is easy to cause performance degradation.
Low shear strength
Interlayershear strength It is borne by resin, so it is very low.By selecting process and usingcoupling agentIn order to improve the interlayer bonding force, the most important thing is to try to avoid shearing between layers during product design.
Production method
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Basically, it is divided into two categories, namely wet contact molding and dry pressure molding.According to the process characteristics, there areHand lay-up , laminated forming, RTM method, extrusion drawing methodCompression Molding , winding forming, etc.Hand lay up molding also includes hand lay up method, bag pressing method, spray method, wet lay up low pressure method and mold free hand lay up method.
There are four molding methods used most in the world.
① Hand pasting method[1]：It is mainly used in Norway, Japan, Britain, Denmark, etc.
Kenny hand paste product: FRP fan
② Jet method:It is mainly used in Sweden, the United States, Norway, etc.
There are also: filament winding molding, pultrusion molding, hot press grouting molding, and so on.
In China, more than 90% of FRP products are produced by hand pasting, and others are molded, wound, laminated, etc.The hand paste method in Japan still accounts for 50%.From the perspective of countries around the world, hand pasting still accounts for a considerable proportion, indicating that it still has vitality.The hand pasting method is characterized by the use of wet resin molding, simple equipment, low cost, and the ability to paste more than 10m of the whole product at a time.The disadvantages are low mechanization, long production cycle and unstable quality.With the development of FRP industry, new process methods will continue to emerge.
application
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Sculpture mold
The production is carried out by first making the FRP sculpture moldFRP productsTo meet the needs of people in real production and life.
Gypsum model point is heat-resistant, inexpensive, small thermal conductivity, and good copy.It is generally used for making master molds.Easy to manufacture, suitable for large products.But it is not durable, afraid of impact, and slow in drying.It is mostly used for single products and products with complex lines, such as relief.The gypsum used is mostly semi hydrated gypsum, i.e. plaster of paris.Like the cement mold, bricks and wood can be used as the skeleton foundation, and then covered with gypsum layer for modeling.In order to improve the rigidity and prevent cracks, sufficient fillers can be added to the gypsum. For example, quartz can reduce shrinkage and cracks, and cement (gypsum: cement=7:3) can be added to increase the strength.It is also proposed to add appropriate amount of emulsion into gypsum and dilute it with water to make a mold, which has good strength and no powder.
Gypsum mold can be used as the master mold of low melting point alloy mold to cast alloy in hot state.When the gypsum master mold is used to reproduce the gypsum mold (sub mold), the surface of the master mold should be coated with a separating agent, such as potassium soap solution, transformer oil, edible oil, 20% stearic acid+80% kerosene, or gasoline+vaseline.The plaster mold can be repaired by dipping a pen with water in plaster powder.The drying process of gypsum mold is: (60 ～ 120) ℃/(4 ～ 5) L, after natural cooling, polish gently with metallographic sandpaper, and then dry (100 ～ 150) ℃/(8 ～ 10) L, (200 ～ 230) ℃/(20 ～ 24) L.
2、 FRP sculpture rubber mold
Silicone rubberPolyurethane resinIt is used to make complex reliefs, round sculptures and various shapes. It is not used alone. It must be composed of other materials such as plaster casting. It is usually used for a part in the mold that cannot be directly demoulded due to linear pouring or overlapping. Because it has a certain softness, it can be pulled out at will after the external mold is demoulded, such aslion, dragons and other animals or bodhisattvas, cartoon characters.Use this method when the batch size is small.
3、 Glass fiber reinforced plastic sculpture paraffin film
The paraffin film is used for products with small quantity or complex lines and difficult demoulding.For example, to manufacture an integral elbow, including a 90 ° elbow, two elbow haves can be used as a master mold. After the inner 90 ° cavity is filled with paraffin, the haves master mold is removed, the paraffin mold core is slightly trimmed, and then the outer wall is coated with glass fiber reinforced plastic, cured, heated, so that the paraffin can melt and flow out, and a whole can be obtainedFRP products。
In order to reduce shrinkage deformation and improve stiffness, 5% stearic acid can be added to paraffin.It is easy to manufacture and demould, and paraffin can be reused.But the precision is not high.Another method: When wet rolling, the steel pipe can be dipped into the wax melted at 70~80 ℃, lifted and cooled before immersion, repeated until the required thickness, the surface can be slightly trimmed to cover the glass fiber reinforced plastic. To prevent cracking of the wax, a small amount of butter can be added to the wax.The wax can also be coated with a thin layer of cellophane, which can be used as the mold core. After the glass fiber reinforced plastic is cured, the steel pipe can be heated to melt the paraffin and then demoulded.
4、 Concrete formwork
Concrete moulds are mostly used for products with regular lines and less repeated use, such as spiral, wavy, round, arch or three-dimensional groove products.With low cost and good rigidity, the foundation can be built with bricks, covered with cement mortar, polished and puttied, and then polished, polished and painted.This cement mold can be directly used for productionFRP productsIt can also be used to reproduce the master mold of the FRP mold.The cement mold dries slowly. Even under normal conditions, surface construction such as painting can only be carried out for more than a week.
5、 Glass fiber reinforced plastic sculpture wood model
Wooden formwork is mainly used for large products with relatively straight lines.Wooden moldIt can be directly used as the forming mold of FRP products, and also as the transition master mold for the reproduction of FRP molds.The wood used for making molds includes Korean pine, ginkgo, Chinese fir, etc., with a water content of 15%, and is not easy to shrink and deform, without knots.After the wooden mold is made, it can be coated with resin (surface putty) of 0.2~0.3 garbage thickness, and then polished four times with water sandpaper from coarse to fine, and finally polished with 800 # or 1000 # sandpaper, and then coated with polishing paste and polished with a polisher, and then coated with paraffin. The wooden mold is ready.It can also be directly painted and polished on the wood mold to make the wood mold.
6、 Glass fiber reinforced plastic sculpture metal mold
metal mouldIn particular, steel dies are generally used for small size and large batch of molded products.Such as stainless steel plate with smooth surface when making glass fiber reinforced plastic plate;Angle steel and channel steel shall be used when making profiles.Because molded products not only need to be pressurized, but also heated.There are also large products with uncomplicated shapes.Brass is a common metal, but it is vulnerable to the corrosion of resin auxiliary agent and will adversely affect the resin curing. Unless the working face has been plated with chromium or other metals, it should not be used.The manufacturing and processing of metal molds are very difficult and costly.In addition, the composition of low melting point alloy mold is: Zn 93%Al4%、Cu3%、Mn0.5%，When the temperature is 50~80 ℃, the alloy hardness (HB) is about 100.It has good fluidity and poor wear resistance, and is suitable for manufacturing plastic molding cavities with complex shapes and fine patterns, and the service temperature is generally>80 ℃.Another low melting point metal is 58% bismuth, 42% tin, melting point 135 ℃.The advantages of low melting point alloy die are short molding cycle, simple process and reusable.
purpose
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FRP tank
FRP is a kind of composite material which has developed rapidly in the past 50 years.70% of the output of glass fiber is used to make glass fiber reinforced plastics.FRP has high hardness and is much lighter than steel.It can be used as fuel tank and pipe in jet aircraft to reduce the weight of aircraft.The mini oxygen bottles carried by the astronauts who landed on the moon are also made of fiberglass.Fiberglass is easy to process, rust proof and does not need paint.China has widely used FRP to manufacture various small boats, lifeboats, yachts, and automobile manufacturing industries, saving a lot of steel.As glass fiber reinforced plastic is a kind of composite material, its performance has a wide range of applications, so its market development prospects are very broad.According to relevant statisticsFRP productsThe number of species has reached about 40000.Although each country has its own development direction according to its own economic development, it has basically involved various industrial sectors.After more than 40 years of development, China's FRP industry has also achieved successful applications in various fields of the national economy and played an important role in economic construction.The main application fields of FRP are roughly summarized as follows:
1. Construction industry:Cooling tower, FRP doors and windows New, building structure, enclosure structure, indoor equipment and decorative parts, FRP plates, corrugated tiles, decorative panelsFRP cover plate, sanitary ware and integral toilet, sauna, surf bathroom, building construction formwork, warehouse buildingConcrete formwork, reinforcement materials, solar energy utilization devices, etc.
2. Chemical industry: corrosion resistant pipes, storage tanks, corrosion resistant transfer pumps and their accessories, corrosion resistant valves, grids, ventilation facilities, sewage and wastewater treatment equipment and its accessories, etc.
3. Automobile and railway transportation industry: automobile shells and other parts, all plastic mini cars, body shells, doors, inner plates, main columns, floors, bottom beams, bumpers, instrument panels of large passenger cars, small passenger and freight cars, and cabs and machine covers of fire tank cars, refrigerated cars, tractors, etc.
4. In terms of railway transportation, there are train window frames, roof bends, roof tanks, toilet floors, luggage car doors, roof ventilators, refrigerated doors, water storage tanks, and some railway communication facilities.
5. In terms of highway construction, there are traffic signs, isolation piers, sign posts, sign boards, highway guardrails, etc., and the boat and water transport industry.
6. Inland river passenger and cargo ships, fishing boats, hovercraft, various yachts, racing boats, high-speed boats, lifeboats, traffic boats, and FRP buoys and mooring buoys, etc.
7. Electrical industry and communication engineering: arc extinguishing equipment, cable protection tube, generator stator coil and support ring and cone shell, insulation tube, insulation rod, motor protection ring,High voltage insulator, standard capacitor shell, bushing for motor cooling, generator wind shield and other strong current equipment;Electrical equipment such as distribution box and panel, insulated shaft, glass fiber reinforced plastic cover, etc;Printed circuit board, antennaRadomeAnd other electronic engineering applications.
With the development of science and technology and the improvement of people's living standards, many civil FRP products have been developed in large quantities, such as manyUrban sculpture, arts and crafts modeling, fast-food tables and chairs, motorcycle parts, FRP flower pots, safety helmets, advanced amusement equipment, household appliance shells, etc., have been successfully applied in a large number.
Can be madeFRP tile, also known as transparent tile. Yes andsteel structureThe supporting daylighting materials are mainly composed of high performanceUpper membrane, reinforced polyester and glass fiberComposition, wherein the upper film should play a very good role in anti ultraviolet and anti-static. Anti ultraviolet is to protect the polyester of FRP daylighting panel from yellowing, aging and premature light loss.Antistatic is to ensure that the dust on the surface can be easily washed away by rain or blown away by wind to maintain a clean and beautiful surface.Due to its stable quality and durable characteristics, it is welcomed by customers. The products can be widely used in industrial/commercial/civil building roofs and walls.
The film industry uses it to make props, which is convenient, fast and cost saving. It can imitate many kinds of material effects and is popular with people.Chemical plants also usephenolic resinGlass fiber reinforced plastic (GRP) instead of stainless steel is used as various corrosion resistant equipment, greatly extending the service life of the equipment.Fiberglass non-magnetic, does not block the passage of electromagnetic waves.Using it as a missile radome is like wearing a pair of protective glasses on the missile, which not only does not block the radar's "line of sight", but also plays a protective role.The radomes of many missiles and ground radar stations are made of FRP.
In the 21st century, according to the good wave transmission and performance of glass fiber reinforced plastic, with the widespread popularity of mobile phone communication, glass fiber reinforced plastic is widely used to manufacture 2G and 3G antenna housings. With its good formability and beautification of appearance, glass fiber reinforced plastic has played a very good role in beautifying residential areas. Products in this area include square column wire covers, simulation stones,The landscaping trees and other fiberglass reinforced plastics used in the field have also made great contributions to improving the level of sports.SincePole vaultSince this sport, the highest record for athletes to use wooden poles is 3.05m.Later, bamboo poles were used.By 1942, the record had risen to 4.77 meters.The advantage of bamboo pole is light and elastic, but the disadvantage is that the lower end is thick and the upper end is thin. It is very difficult to improve the record, so people use aluminum alloy pole instead of bamboo pole. Although it is light and firm, it is not flexible enough.In this way, from 1942 to 1957, the highest record of pole vault was only increased by 1 cm in 15 years.But since the emergence of the new FRP pole, the record has risen rapidly due to its light and flexiblePole vaultThe record has exceeded 6 metersthe highest level。
Today, FRP is also widely used in people's life. Because some of its special varieties can still retain many advantages of glass, such as transparency, people use it as window glass, which can not only block the ultraviolet rays in the sun, but also make the room bright.People also use it to make various durable daily necessities.Such as bath, kitchen and toilet appliances.
Development prospect
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FRP is a kind of composite material. Due to its unique performance advantages, FRP material has been widely used in more than ten related industries, such as aerospace, railway, decorative buildings, home furniture, advertising display, craft gifts, building materials and sanitary ware, yacht berthing, sports materials, environmental sanitation engineering, and is highly praised,It has become the demand darling of merchants in the new era of material industry.FRP productsIs also different fromTraditional materialsThe products are much better than traditional products in terms of performance, use and life.Its characteristics of easy modeling, customizable, and color random deployment are favored by businesses and sellers, and it has a growing market share and broad prospects!
These industries are as follows: ferrous metallurgy, nonferrous metallurgy, power industry, coal industry, petrochemical industry, chemical industry, electromechanical industry, textile industry, automobile and motorcycle manufacturing industry, railway industry, shipbuilding industry, construction industry, light industry, food industry, electronics industry, post and telecommunications industry, culture, sports and entertainment industry, agriculture, commerce, medicine and health industry,And military and civil applications.
The main FRP product categories involved in the application of these industrial sectors include: mine ventilation equipment, coking and related equipment, rare earth smelting and ferroalloy smelting related equipment, cold rolling and electroplating equipment, power transmission and transformation equipmentWind power generation equipment, water pipes for thermal power generation, cooling water equipment, power management and maintenance tools and instruments, coal mine phoenix tubesExplosion proof water bagExplosion proof devices, oil exploitation related parts and equipment, petrochemical equipment, chemical equipment, chemical construction materials, mine ventilation equipment, motor parts, spare parts, electroplating equipment, wind turbines and parts, textile printing and dyeing equipment, facilities and parts, automobile manufacturing materials and parts, automobile maintenance materials, motorcycle manufacturing materials and parts,Materials and related facilities for railway rolling stock, materials and related components for railway signal system, various kinds of rivers, lakes and seas boats, supporting parts and auxiliary facilities for large steel boats, building facilities and materials, toilets, kitchensdoors and windowsCorrugated tile, cooling tower, building ventilation and air conditioning facilitiesBuilding formworkRelevant facilities for light industry, daily chemical and paper industry, household appliances, alcohol, tanning, furniture materials, food storage tanks, equipment for electronic industry, materials for consumer goods and electronic equipment accessories, postal and telecommunications equipment supporting facilities, sports equipment, recreation equipment and related facilities, agricultural sprinkler irrigation equipment, greenhouses, agricultural machinery accessories, refrigerators, aquaculture,Commercial counter, commercial packing box, commercial cold storage, medical industrial facilities, medical and health purposes, etc.
