Filling and reinforcement modification of Wuhan Hyundai polymer
DATE：2020/12/24 9:07:10 / READ： / SOURCE：This station
Filling and reinforcement modification of Wuhan Hyundai polymer
Filling and reinforcement are important methods for modifying plastics, which can expand the application range of the original plastics and have new or special functions. Due to the development of new filling and reinforcing agents in recent years, and the application of new surface treatment technologies, the filling and reinforcing technology has been further developed.
Filling materials-generally considered to have no enhancement effect, only serve as an extender, and are mainly used to reduce costs. However, the filler also has a certain modification effect on the resin, such as increasing the hardness, improving the heat resistance and dimensional stability, reducing the mold shrinkage and thermal expansion. In addition, selection of appropriate filler materials (type and shape) and surface treatment can improve combustion resistance, chemical resistance, electrical insulation, and moldability.
The commonly used fillers are as follows:
1.Calcium carbonate
The most important carbon salt filler is calcium carbonate. Because of its low price and abundant sources, it is mainly processed from natural limestone. www.handern.com PP Spunbond Nonwoven Equipment
There are two methods for preparing calcium carbonate: mechanical pulverization and chemical precipitation. The product prepared by the former method is called heavy calcium carbonate, and the latter is called light calcium carbonate.
Heavy calcium carbonate is obtained by mechanical crushing of natural limestone. There are two crushing methods: dry and wet. Thousand method is to dry the lime with an impact crusher such as a crusher, and then divide it into an appropriate particle size with an air classifier. The wet method is to use a roller mill or a ball mill to add water to wet crushing, and then use water to classify the particles. Most of the calcium carbonate used for plastic filling is produced by dry methods. The particle size is 2-10um, and the specific surface area is 2-7m2/g.
Light calcium carbonate is obtained by chemically treating high-quality limestone, decomposing and purifying and sedimenting. Among them, the particle size of extremely fine active calcium carbonate is below 0.1um, and the specific area is 25-80m/g.
In addition to being used as an extender in plastics, calcium carbonate can also be used as a viscosity modifier for PVC paste and unsaturated polyester. Ultra-fine calcium carbonate particles below 0.1um, if treated with surface treatment agents (such as fatty acids, resin acids, etc.), have particularly good dispersibility in plastics, and the finished products have good gloss. They can be used as reinforcing fillers or physical improvements.剂用。 Agent use.
2. Talc
It is selected from crushed natural talc. The main component is hydrous magnesium silicate. The talc crystals belong to the monoclinic system and are hexagonal or rhombus. The chemical property is inactive, the powder is extremely soft and has a smooth feeling. The most significant use in plastics is a white fine powder composed of flakes. Due to the flat characteristics of this special shape of talc, it is considered a reinforcing filler in plastics. Compared with calcium carbonate, composite materials filled with flat talc, whether processed at room temperature or high temperature, always show higher stiffness and creep resistance. For example, filled polypropylene with a 40% talc content has three times the stiffness of unfilled polypropylene; while 40% calcium carbonate has a rigidity twice that of unfilled polypropylene. As the amount of filler increases, the impact strength decreases. Of course, this effect can be minimized by appropriately selecting talc particle size, particle size distribution, surface treatment and resin formulation. www.handern.com PP Spunbond Nonwoven Equipment
3. Kaolin
Kaolin, also known as clay, is a hydrated aluminum silicate mineral. There are naturally hydrated kaolin and calcined anhydrous kaolin. Kaolin of larger particle size is composed of massive and flaky particles, while the small particle size part is almost all flaky.
The hydrated kaolin is non-abrasive, chemically stable and has a high specific surface area, which increases the viscosity. Kaolin can be used to adjust the fluidity of materials in most plastics to achieve a more uniform composite. Fine grade kaolin (especially surface-treated kaolin) can increase the tensile strength and modulus of low glass transition temperature thermoplastics without significantly reducing its elongation and impact strength.
4. Hollow microspheres
Hollow microspheres refer to hollow thin-walled spheres composed of organic or inorganic materials, with a diameter of tens to hundreds of microns. According to the materials constituting the hollow microspheres, the hollow microspheres can be divided into three categories, namely, inorganic microspheres, organic microspheres and metal microspheres.
The materials of inorganic microspheres are: alumina, silica, glass, ceramics, sodium silicate, phosphate and so on.
The materials of organic microspheres include natural organics such as soybean protein, cellulose derivatives, and natural rubber latex; synthetic organic materials include phenolic resin, urea resin, polyvinyl alcohol, polyamide and so on. www.handern.com PP Spunbond Nonwoven Equipment
The metal microspheres are made of metal materials such as tungsten.
The manufacturing method of hollow microspheres can melt the raw materials and use the viscosity and surface tension to form hollow spheres covered with air by means of air injection.
The general characteristics of this type of filler are low relative density, heat resistance, chemical resistance, low thermal and electrical conductivity, and low chemical activity. Hollow microspheres are mainly used in the following aspects:
(1) Make use of its low density and high strength as various buoyant materials for marine development, synthetic wood, synthetic marble, cement and refractory lightweight framework materials.
(2) Taking advantage of its heat resistance, insulation and low density, it can be filled with epoxy and novolac to make the "Apollo" insulation cover. It is a honeycomb structure that can protect astronauts from returning to the atmosphere.
(3) The use of adsorption properties can be used to produce oil trapping materials and filtering materials.
5. Wood flour
Wood flour is mainly obtained from soft wood such as pine and poplar after removing the bark and knots of the tree and then mechanically crushing and grinding. The fine powder made from various kinds of wood can be divided into different grades such as 15-30 days, 30-50 mesh, 50-80 mesh, and above 80 mesh.
Wood flour can be used as a filler for phenolic, urea-formaldehyde, melamine, polyvinyl chloride and other plastics. The resulting products have excellent electrical properties and impact resistance, but the color tone, water resistance and heat resistance are slightly poor. www.handern.com PP Spunbond Nonwoven Equipment
6. Asbestos
Asbestos is a general term for a class of hydrated metal silicates. According to its chemical composition and crystal structure, it can be divided into chrysotile and crocidolite. Chrysotile is a silicate of magnesium with long fibers and high strength and flexibility: crocidolite includes silicates of magnesium, iron, calcium, and sodium. The fibers are short or powdery. Asbestos has excellent properties such as heat resistance, acid resistance and salt resistance. It is chemically inactive and is a poor conductor of heat and electricity.
The main advantage of using asbestos in thermoplastics is that it can greatly enhance the modulus, increase the thermal deformation temperature and significantly reduce the thermal expansion coefficient. When asbestos is used in thermosetting resins, it can significantly increase the elastic modulus and flexural strength. The main disadvantage of using asbestos is to reduce the impact strength, but if the asbestos fiber is specially treated, this disadvantage can be reduced to a minimum.
Filling and reinforcement are important methods for modifying plastics, which can expand the application range of the original plastics and have new or special functions. Due to the development of new filling and reinforcing agents in recent years, and the application of new surface treatment technologies, the filling and reinforcing technology has been further developed.
Filling materials-generally considered to have no enhancement effect, only serve as an extender, and are mainly used to reduce costs. However, the filler also has a certain modification effect on the resin, such as increasing the hardness, improving the heat resistance and dimensional stability, reducing the mold shrinkage and thermal expansion. In addition, selection of appropriate filler materials (type and shape) and surface treatment can improve combustion resistance, chemical resistance, electrical insulation, and moldability.
The commonly used fillers are as follows:
1.Calcium carbonate
The most important carbon salt filler is calcium carbonate. Because of its low price and abundant sources, it is mainly processed from natural limestone. www.handern.com PP Spunbond Nonwoven Equipment
There are two methods for preparing calcium carbonate: mechanical pulverization and chemical precipitation. The product prepared by the former method is called heavy calcium carbonate, and the latter is called light calcium carbonate.
Heavy calcium carbonate is obtained by mechanical crushing of natural limestone. There are two crushing methods: dry and wet. Thousand method is to dry the lime with an impact crusher such as a crusher, and then divide it into an appropriate particle size with an air classifier. The wet method is to use a roller mill or a ball mill to add water to wet crushing, and then use water to classify the particles. Most of the calcium carbonate used for plastic filling is produced by dry methods. The particle size is 2-10um, and the specific surface area is 2-7m2/g.
Light calcium carbonate is obtained by chemically treating high-quality limestone, decomposing and purifying and sedimenting. Among them, the particle size of extremely fine active calcium carbonate is below 0.1um, and the specific area is 25-80m/g.
In addition to being used as an extender in plastics, calcium carbonate can also be used as a viscosity modifier for PVC paste and unsaturated polyester. Ultra-fine calcium carbonate particles below 0.1um, if treated with surface treatment agents (such as fatty acids, resin acids, etc.), have particularly good dispersibility in plastics, and the finished products have good gloss. They can be used as reinforcing fillers or physical improvements.剂用。 Agent use.
2. Talc
It is selected from crushed natural talc. The main component is hydrous magnesium silicate. The talc crystals belong to the monoclinic system and are hexagonal or rhombus. The chemical property is inactive, the powder is extremely soft and has a smooth feeling. The most significant use in plastics is a white fine powder composed of flakes. Due to the flat characteristics of this special shape of talc, it is considered a reinforcing filler in plastics. Compared with calcium carbonate, composite materials filled with flat talc, whether processed at room temperature or high temperature, always show higher stiffness and creep resistance. For example, filled polypropylene with a 40% talc content has three times the stiffness of unfilled polypropylene; while 40% calcium carbonate has a rigidity twice that of unfilled polypropylene. As the amount of filler increases, the impact strength decreases. Of course, this effect can be minimized by appropriately selecting talc particle size, particle size distribution, surface treatment and resin formulation. www.handern.com PP Spunbond Nonwoven Equipment
3. Kaolin
Kaolin, also known as clay, is a hydrated aluminum silicate mineral. There are naturally hydrated kaolin and calcined anhydrous kaolin. Kaolin of larger particle size is composed of massive and flaky particles, while the small particle size part is almost all flaky.
The hydrated kaolin is non-abrasive, chemically stable and has a high specific surface area, which increases the viscosity. Kaolin can be used to adjust the fluidity of materials in most plastics to achieve a more uniform composite. Fine grade kaolin (especially surface-treated kaolin) can increase the tensile strength and modulus of low glass transition temperature thermoplastics without significantly reducing its elongation and impact strength.
4. Hollow microspheres
Hollow microspheres refer to hollow thin-walled spheres composed of organic or inorganic materials, with a diameter of tens to hundreds of microns. According to the materials constituting the hollow microspheres, the hollow microspheres can be divided into three categories, namely, inorganic microspheres, organic microspheres and metal microspheres.
The materials of inorganic microspheres are: alumina, silica, glass, ceramics, sodium silicate, phosphate and so on.
The materials of organic microspheres include natural organics such as soybean protein, cellulose derivatives, and natural rubber latex; synthetic organic materials include phenolic resin, urea resin, polyvinyl alcohol, polyamide and so on. www.handern.com PP Spunbond Nonwoven Equipment
The metal microspheres are made of metal materials such as tungsten.
The manufacturing method of hollow microspheres can melt the raw materials and use the viscosity and surface tension to form hollow spheres covered with air by means of air injection.
The general characteristics of this type of filler are low relative density, heat resistance, chemical resistance, low thermal and electrical conductivity, and low chemical activity. Hollow microspheres are mainly used in the following aspects:
(1) Make use of its low density and high strength as various buoyant materials for marine development, synthetic wood, synthetic marble, cement and refractory lightweight framework materials.
(2) Taking advantage of its heat resistance, insulation and low density, it can be filled with epoxy and novolac to make the "Apollo" insulation cover. It is a honeycomb structure that can protect astronauts from returning to the atmosphere.
(3) The use of adsorption properties can be used to produce oil trapping materials and filtering materials.
5. Wood flour
Wood flour is mainly obtained from soft wood such as pine and poplar after removing the bark and knots of the tree and then mechanically crushing and grinding. The fine powder made from various kinds of wood can be divided into different grades such as 15-30 days, 30-50 mesh, 50-80 mesh, and above 80 mesh.
Wood flour can be used as a filler for phenolic, urea-formaldehyde, melamine, polyvinyl chloride and other plastics. The resulting products have excellent electrical properties and impact resistance, but the color tone, water resistance and heat resistance are slightly poor. www.handern.com PP Spunbond Nonwoven Equipment
6. Asbestos
Asbestos is a general term for a class of hydrated metal silicates. According to its chemical composition and crystal structure, it can be divided into chrysotile and crocidolite. Chrysotile is a silicate of magnesium with long fibers and high strength and flexibility: crocidolite includes silicates of magnesium, iron, calcium, and sodium. The fibers are short or powdery. Asbestos has excellent properties such as heat resistance, acid resistance and salt resistance. It is chemically inactive and is a poor conductor of heat and electricity.
The main advantage of using asbestos in thermoplastics is that it can greatly enhance the modulus, increase the thermal deformation temperature and significantly reduce the thermal expansion coefficient. When asbestos is used in thermosetting resins, it can significantly increase the elastic modulus and flexural strength. The main disadvantage of using asbestos is to reduce the impact strength, but if the asbestos fiber is specially treated, this disadvantage can be reduced to a minimum.
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