Halogen-free flame retardant wood-plastic composite material and preparation method thereof

Abstract

The invention discloses a halogen-free flame retardant wood-plastic composite material which is prepared from the following raw materials: a natural fiber, plastic, a fire retardant, a compatilizer, an antioxidant, a lubricant and a coupling reagent. The preparation method comprises the following steps: drying the natural fiber in advance; mixing the dried natural fiber with the coupling agent evenly, and placing for 3-10 minutes; fully mixing the mixture with the fire retardant, the plastic, the compatilizer, the lubricant and the antioxidant; and extruding, plastifying, dicing, and carrying out injection molding. The wood-plastic composite material disclosed by the invention does not contain halogen; the composite fire retardant is introduced into a formula system, and works together with other components, so that high flame retardant property can be achieved; specifically, the 1.5mm UL94 V-0 flame retardant level can be achieved; LOI is over 30; and the formula system disclosed by the invention contains the composite fire retardant, but the mechanical property of the composite material is relatively good.

Description

technical field [0001] The invention relates to a halogen-free flame-retardant wood-plastic composite material and a preparation method thereof. Background technique [0002] Wood-plastic composite materials are very environmentally friendly. It mainly adds wood powder, bamboo powder, straw, rice husk and other plant fibers into the resin matrix to form composite materials. The characteristics of this composite material are in line with the rational use of human resources, health and environmental protection. The concept of sustainable development is also in line with our country's call for "building a conservation-oriented society". [0003] At present, the halogen-free flame retardants commonly used in wood-plastic composite materials mainly include metal hydroxides, zinc borate, nano-clay particles, ammonium polyphosphate, red phosphorus, and expanded graphite. Among them, metal hydroxide has the advantages of good thermal stability, low smoke generation, non-toxicity, a...

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Problems solved by technology

Among them, metal hydroxide has the advantages of good thermal stability, low smoke generation, non-toxicity, and no corrosive gas. However, the filling amount generally exceeds 50% to show a good flame retardant effect, which seriously affects wood. The processing and mechanical properties of plastic composite materials; ammonium polyphosphate is an intumescent flame retardant, which can promote the formation of carbon foam layer when the material is burned, which has the functions of heat insulation, oxygen insulation, smoke suppression, and anti-drip. Adding more than 15% will have a good flame retardant effect, which is not suitable for wood-plastic composite materials with high flame retardant requirements; red phosphorus and expanded graphite have high flame retardant efficiency, and 10% addition can make the material flammable significantly Reduced, but it is not suitable for oxygen-free polymers such as polypropylene (PP), polyethylene (PE), EVA (ethylene-vinyl acetate copolymer), ABS (acrylonitrile-butadiene-styrene copolymer), The flame retardant effect of polystyrene (PS) is not ideal, and the resin matrix usually used for wood-plastic composite materials is polypropylene (PP) or polyethylene (PE), so red phosphorus is used for PP or PE-based resins. The flame retardancy of wood-plastic composite materials is not good, and it has too much influence on the color of the material, so it is difficult to be widely used; all the above-mentioned common wood-plastic flame retardants are difficult to make the composite material reach the flame retardancy of 1.5mm UL94 V-0. fuel level

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