Bewise Inc. www.tool-tool.com
Reference source from the internet.
The wood-plastics composites (WPC) industry has experienced rapid growth in North America. The growing commercial importance of these materials has expanded efforts for understanding the structure-relationship and for exploring new methodologies for producing new materials.
WPC are typically made using 30% to 60% wood filler or reinforcements. Wood flour can be used as a filler to reduce raw material costs, improve stiffness, and improve dimensional stability with temperature changes with minimal weight increase. When appropriate coupling agents are added to improve fiber-matrix adhesion, wood and other natural fibers can also be used as a reinforcing fiber to strengthen thermoplastics. Wood flour is made commercially by grinding postindustrial material, such as planer shavings, chips, and sawdust, into a fine, flour-like consistency. Wood fiber, although more difficult to process than wood flour, can lead to superior composite properties and act more as reinforcement than as filler. Wood fiber is available from both virgin and recycled sources, including pallets, demolition lumbers, and old newsprints. Wood from small-diameter trees and under-utilized species can also be used. Besides wood, many particle and fiber types have been investigated, such as wheat, kenaf, cornstalk, and jute.
Thermoplastic resins, such as polypropylene, low- and high-density polyethylene, polystyrene, and polyvinyl chloride, soften when heated and harden when cooled. This property allows other materials, such as wood fiber, to be mixed with the plastic to form a composite product. The resulting WPC can be easily processed into various shapes and can be recycled. Additives are also often used in WPC. Additives are materials that are added in small amounts to enhance properties. These additives can improve bonding between the thermoplastic and wood component (for example, coupling agents), product performance (impact modifiers, UV stabilizers, flame retardants), and process ability (lubricants).
The mold-ability of plastic allows complex product design. In addition, these composites are attractive in the environmental sense, because both waste wood and recycled thermoplastics can be used to make these products. In brief, WPC could be products that can look like woods but can be processed like plastics. Thermoplastics reinforced with wood and other natural fibers are becoming more commonplace in building construction, especially in the outdoor decking and window products markets.
The manufacture of thermoplastic composites is usually a two-step process. The raw materials are first mixed together, and the composite blend is then formed into a product. The combination of these steps is called in-line processing, and the result is a single processing step that converts raw materials to end products. Compounding is the feeding and dispersing of the lignocellulosic component in a molten thermoplastic to produce a homogeneous material. Various additives are added and moisture is removed during compounding. The compounded material can be immediately pressed or shaped into an end product while still in its molten state or become a kind of small, regular pellets for future reheating and forming. Three common forming methods for WPC are extrusion (forcing molten composite through a die), injection molding (forcing molten composite into a cold mold), and compression molding (pressing molten composite between mold halves) .Several factors influence processing WPC. Moisture can disrupt many thermoplastic processes, resulting in poor surface quality and voids. The wood material must be pre-dried or processed by vented equipment used. Also, melt temperatures should be kept below 200°C (392°F) because prolonged exposure to high temperatures can result in release of volatiles, discoloration, odor, and degradation of the wood componen.
This new composite takes advantage of wood’s low density, low cost, UV resistance, and machining properties, while the thermoplastic component facilitates flow during melt processes and acts as a barrier layer to retard moisture intrusion and biological attack. The properties of the composites are dependent not only on the lignocellulosic materials and polymers, but also on the average size of wood flour. Mechanical and physical properties, such as strength, stiff-ness, impact resistance, density, and color, are important considerations in many WPC applications. Different applications take advantage of properties that WPC offer. Some researches indicate that wood fiber-plastic composite panels are inferior to conventional wood-based panels in bending modulus of elasticity and bending modulus of rupture. However, the composite panels performed well in thickness swell and moisture absorption. The rate of moisture sorption and ultimately the rate of decay will depend on wood particle size and geometry, wood/polymer ratio and presence of other compounds that may repel water. About the fastener performance, the screw withdrawal, nail withdrawal, and nail head pull-through capacity are relatively unaffected by wood flour content. However, wood flour content affected lateral nail resistance. The use of pilot holes (pre-drilling) was found to have little effect on fastener capacity. The screw withdrawal capacity of the tested wood flour-thermoplastic composite panels was found to be equal to or greater than that of conventional wood panel products.
In the building community, there is a growing demand for high-performance, low-maintenance, and low-cost building products. To meet this demand, natural fiber thermoplastic composites are being used to produce such products as landscape timbers, railing, decking, fence, window and door elements, panels, molding, roofing, and siding, even floor ,louver, and indoor furniture have been reported. Manufacturers usually promote its lower maintenance, lack of cracking or splintering, and high durability. The actual lifetime of WPC lumber is currently being debated; most manufacturers offer a 10-year warranty. Compared with unfilled plastic lumber, the advantages of WPC lumber include increased stiffness and reduced thermal expansion. However, mechanical properties such as creep resistance, stiffness, and strength are lower than those of solid wood. Hence, these composites are not currently being used in applications that require considerable structural performance.
The phase-out of chromated copper arsenate (CCA) may give WPC opportunities to increase awareness of alternatives to CCA-treated lumber. One of the major challenges for WPC is to optimize the processing operations of the wood filled plastics to reduce costs and compete with solid wood and conventional wood composite products. Nowadays, many researchers and manufacturers work for improving all kinds of properties of WPC. The future of WPC will depend on many factors, including new product identification, product quality, consumer reaction and reaction, and success of research and development efforts. Success will also depend on how well the forest products and plastics industries continue to establish relationships and work with each other.
Welcome to BW tool world! We are an experienced tool maker specialized in cutting tools. We focus on what you need and endeavor to research the best cutter to satisfy users’ demand. Our customers involve wide range of industries, like mold & die, aerospace, electronic, machinery, ,,,etc. We are professional expert in cutting field. We would like to solve every problem from you. Please feel free to contact us, it’s our pleasure to serve for you.
BW product including: utting tool、HSS Cutting tool、Carbide end mills、Carbide cutting tool、NAS Cutting tool、Carbide end mill、Aerospace cutting tool、Carbide drill、High speed steel、Milling cutter、Core drill、Taperd end mills、Metric end mills、Miniature end mills、Pilot reamer、Electronics cutter、Step drill、Metal cutting saw、Double margin drill、Gun barrel、Angle milling cutter、Carbide burrs、Carbide tipped cutter、Chamfering tool、IC card engraving cutter、Side cutter、NAS tool、DIN tool、Special tool、Metal slitting saws、Shell end mills、Side and face milling cutters、Side chip clearance saws、Long end mills、Stub roughing end mills、Dovetail milling cutters、Carbide slot drills、Carbide torus cutters、Angeled carbide end mills、Carbide torus cutters、Carbide ball-noseed slot drills、Mould cutter、Tool manufacturer.
Bewise Inc. www.tool-tool.com
Reference source from the internet.
The wood-plastics composites (WPC) industry has experienced rapid growth in North America. The growing commercial importance of these materials has expanded efforts for understanding the structure-relationship and for exploring new methodologies for producing new materials.
WPC are typically made using 30% to 60% wood filler or reinforcements. Wood flour can be used as a filler to reduce raw material costs, improve stiffness, and improve dimensional stability with temperature changes with minimal weight increase. When appropriate coupling agents are added to improve fiber-matrix adhesion, wood and other natural fibers can also be used as a reinforcing fiber to strengthen thermoplastics. Wood flour is made commercially by grinding postindustrial material, such as planer shavings, chips, and sawdust, into a fine, flour-like consistency. Wood fiber, although more difficult to process than wood flour, can lead to superior composite properties and act more as reinforcement than as filler. Wood fiber is available from both virgin and recycled sources, including pallets, demolition lumbers, and old newsprints. Wood from small-diameter trees and under-utilized species can also be used. Besides wood, many particle and fiber types have been investigated, such as wheat, kenaf, cornstalk, and jute.
Thermoplastic resins, such as polypropylene, low- and high-density polyethylene, polystyrene, and polyvinyl chloride, soften when heated and harden when cooled. This property allows other materials, such as wood fiber, to be mixed with the plastic to form a composite product. The resulting WPC can be easily processed into various shapes and can be recycled. Additives are also often used in WPC. Additives are materials that are added in small amounts to enhance properties. These additives can improve bonding between the thermoplastic and wood component (for example, coupling agents), product performance (impact modifiers, UV stabilizers, flame retardants), and process ability (lubricants).
The mold-ability of plastic allows complex product design. In addition, these composites are attractive in the environmental sense, because both waste wood and recycled thermoplastics can be used to make these products. In brief, WPC could be products that can look like woods but can be processed like plastics. Thermoplastics reinforced with wood and other natural fibers are becoming more commonplace in building construction, especially in the outdoor decking and window products markets.
The manufacture of thermoplastic composites is usually a two-step process. The raw materials are first mixed together, and the composite blend is then formed into a product. The combination of these steps is called in-line processing, and the result is a single processing step that converts raw materials to end products. Compounding is the feeding and dispersing of the lignocellulosic component in a molten thermoplastic to produce a homogeneous material. Various additives are added and moisture is removed during compounding. The compounded material can be immediately pressed or shaped into an end product while still in its molten state or become a kind of small, regular pellets for future reheating and forming. Three common forming methods for WPC are extrusion (forcing molten composite through a die), injection molding (forcing molten composite into a cold mold), and compression molding (pressing molten composite between mold halves) .Several factors influence processing WPC. Moisture can disrupt many thermoplastic processes, resulting in poor surface quality and voids. The wood material must be pre-dried or processed by vented equipment used. Also, melt temperatures should be kept below 200°C (392°F) because prolonged exposure to high temperatures can result in release of volatiles, discoloration, odor, and degradation of the wood componen.
This new composite takes advantage of wood’s low density, low cost, UV resistance, and machining properties, while the thermoplastic component facilitates flow during melt processes and acts as a barrier layer to retard moisture intrusion and biological attack. The properties of the composites are dependent not only on the lignocellulosic materials and polymers, but also on the average size of wood flour. Mechanical and physical properties, such as strength, stiff-ness, impact resistance, density, and color, are important considerations in many WPC applications. Different applications take advantage of properties that WPC offer. Some researches indicate that wood fiber-plastic composite panels are inferior to conventional wood-based panels in bending modulus of elasticity and bending modulus of rupture. However, the composite panels performed well in thickness swell and moisture absorption. The rate of moisture sorption and ultimately the rate of decay will depend on wood particle size and geometry, wood/polymer ratio and presence of other compounds that may repel water. About the fastener performance, the screw withdrawal, nail withdrawal, and nail head pull-through capacity are relatively unaffected by wood flour content. However, wood flour content affected lateral nail resistance. The use of pilot holes (pre-drilling) was found to have little effect on fastener capacity. The screw withdrawal capacity of the tested wood flour-thermoplastic composite panels was found to be equal to or greater than that of conventional wood panel products.
In the building community, there is a growing demand for high-performance, low-maintenance, and low-cost building products. To meet this demand, natural fiber thermoplastic composites are being used to produce such products as landscape timbers, railing, decking, fence, window and door elements, panels, molding, roofing, and siding, even floor ,louver, and indoor furniture have been reported. Manufacturers usually promote its lower maintenance, lack of cracking or splintering, and high durability. The actual lifetime of WPC lumber is currently being debated; most manufacturers offer a 10-year warranty. Compared with unfilled plastic lumber, the advantages of WPC lumber include increased stiffness and reduced thermal expansion. However, mechanical properties such as creep resistance, stiffness, and strength are lower than those of solid wood. Hence, these composites are not currently being used in applications that require considerable structural performance.
The phase-out of chromated copper arsenate (CCA) may give WPC opportunities to increase awareness of alternatives to CCA-treated lumber. One of the major challenges for WPC is to optimize the processing operations of the wood filled plastics to reduce costs and compete with solid wood and conventional wood composite products. Nowadays, many researchers and manufacturers work for improving all kinds of properties of WPC. The future of WPC will depend on many factors, including new product identification, product quality, consumer reaction and reaction, and success of research and development efforts. Success will also depend on how well the forest products and plastics industries continue to establish relationships and work with each other.
Welcome to BW tool world! We are an experienced tool maker specialized in cutting tools. We focus on what you need and endeavor to research the best cutter to satisfy users’ demand. Our customers involve wide range of industries, like mold & die, aerospace, electronic, machinery, ,,,etc. We are professional expert in cutting field. We would like to solve every problem from you. Please feel free to contact us, it’s our pleasure to serve for you.
BW product including: utting tool、HSS Cutting tool、Carbide end mills、Carbide cutting tool、NAS Cutting tool、Carbide end mill、Aerospace cutting tool、Carbide drill、High speed steel、Milling cutter、Core drill、Taperd end mills、Metric end mills、Miniature end mills、Pilot reamer、Electronics cutter、Step drill、Metal cutting saw、Double margin drill、Gun barrel、Angle milling cutter、Carbide burrs、Carbide tipped cutter、Chamfering tool、IC card engraving cutter、Side cutter、NAS tool、DIN tool、Special tool、Metal slitting saws、Shell end mills、Side and face milling cutters、Side chip clearance saws、Long end mills、Stub roughing end mills、Dovetail milling cutters、Carbide slot drills、Carbide torus cutters、Angeled carbide end mills、Carbide torus cutters、Carbide ball-noseed slot drills、Mould cutter、Tool manufacturer.
Bewise Inc. www.tool-tool.com
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