Processing of wood-plastic composite material

Processing of wood-plastic composite material forming the main and auxiliary materials of good quality, reasonable craft recipes and die design, extrusion equipment and auxiliary equipment with excellent performance. The process conditions are the structure of the extruder, the quality of the main and auxiliary materials, and material ratio. The role of the plastic base material is heated in the molding process and the shearing force, prone to aging caused by the material degradation, organic material increased brittleness, strength is lowered; easily charred wood filler in the molding process, also cause the material to lose value . Therefore, wood-plastic composite molding process conditions as well as the processing of raw materials is a key technology. 4.8m composite decking

1.1 Processing

At present, the primary molding method used in the industrial production: extrusion molding, injection molding, and hot press molding. Extrusion molding cycle is short, high efficiency, simple process, so the broader. Extrusion molding process consists of a single-screw or twin-screw extruder Extrusion, of arbitrary length can be continuously extruded sheet. The process can be divided into single extrusion composite extrusion two. Composite extrusion is synchronized appearance of the plastic sheet extrusion layer of pure plastic surface, plastic sheet for special occasions.

1.2 process recipe

The formula is the key to determine the performance of wood-plastic composites. Plastic and wood flour wood fiber characteristics and requirements of the use of wood-plastic composites molding process requirements, the main consideration in the design formula: (1) wood flour / wood fiber: to improve the stiffness of the composite, and make wood strengthening agent the texture; (2): Increases the strength of composite materials; (3) coupling agent: to improve the interface between the wood flour / wood fiber and matrix resin binding force; (4) stability and antioxidants: slowing plastic and wood powder / wood fiber drop wood-plastic composite materials processing applications and research progress - improving the composite interface compatibility

1.3 improve the composite interface compatibility

The wooden materials are mainly composed of cellulose, hemicellulose and lignin composition unevenness anisotropic natural polymer composite material, also contain a variety of extracts and other ingredients, and therefore very complex interface characteristics. Since the cellulose, hemicellulose, and lignin containing a large number of polar. Therefore, in the development of a wood fiber - plastic composite material, the need to solve the biggest problem is how to make a hydrophilic polar wood surface with the hydrophobic interface between the non-polar plastic substrates having a good compatibility, so that the wooden material the surface layer and the surface of the plastic layer between intermolecular fusion, to produce a more excellent performance than a single material. To achieve this objective, domestic and a lot of research work in this regard. weatherproof outdoor decking

2.1 interface fusogen processing

The fusion of a method of improving the interface of the two different kinds of joining interface fusogen. The principle is the interface fusion bonding agent in some of the component with a polymer blending component with another polymer blending, and ultimately achieve a fusion between the two polymers. This method can also be used in wood-plastic composite material systems, in order to improve the adhesion between the wood filler and polymeric substrate and performance. While using this method can not make to achieve complete fusion of the two materials, but can reduce the energy of the interface, and to achieve better tack and so that the interface between the timber and the plastic polymer.

2.2 plastic surface pretreatment

Conducted on the plastic substrate, the chemical modification method, the radical exist under conditions of polyethylene subjected to an addition reaction with maleic anhydride (MA), the MA on the polar group is introduced into the non-polar poly ethylene molecule, so that the modified polyethylene has a certain polarity. In this modified polyethylene and wood composite to improve the mechanical strength of the wood-plastic composites. However, this modified method of the polyethylene molecular chain low graft ratio of the polar group, and prone to self-polymerization of MA or polyethylene in the modification process, there are many reactions in the graft copolymerization reaction, thereby affect the modification effect. about wpc prodcuts suppliers

2.3 wood flour / wood fiber surface pretreatment

Pretreatment physical and chemical methods

Wherein the physical method since the discharge process, such as low-temperature plasma discharge, a sputtering discharge, corona discharge, etc.. Changes of low-temperature plasma discharge treatment mainly caused by chemical modification, polymerization, radical generator. The role of the plasma include the proton obtained as well as the generation of the labile group, so that the changes in the functional groups of alcohols, aldehydes, ketones, carboxylic acids, etc.; sputtering discharge treatment is mainly caused by changes in the physical aspects of, for example, the surface becomes rough, ; corona discharge is provided by changing the surface of the cellulose molecule can be to reduce the melt viscosity of the composite material in order to enhance the interface between the bonding properties. Discharge treatment can reduce the the fiber polymer melt viscosity in order to improve the mechanical properties of the composite material. about wpc wpc suppliers
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