
| Physical/Chemical Properties | Specifications |
| Acidity (pH) | 3.5 - 4.6 |
| Density | 0.66 P>Density |
| Solubility in Water | Less than 0.1% |
| Ash Content | .23 to 0.25 Hardgrove Index |
| Moisture Content | 4% to 6% (depends on relative humidity) |
| Specific Gravity | 0.5-0.8 |
| Colour | Brown (light) to tan |
Thermoplastic Resins
The choice of resin selected for use in thermoplastic composites is dependent on many factors. Wood tends to a show a nature for degradation at higher temperatures, so a thermoplastic resins which can be processed at a temperature below 2000, centigrade is to be selected for processing of the composites. Let's have look at the choices available for thermoplastics available for extruded plastic profile.
| Polyethylene(PE) | Polypropylene | PVC |
| Relatively less expensive | Good service temperature | Strongest resin |
| Excellent toughness and impact strength | Lowest Density as compared To PE and PVC | Highest service temperature, |
| Can be used both in virgin & recycled form | Best suited to building and automobiles | Excellent weather resistance |
| Shows a tendency to stabilize against thermal degradation | Has a tendency towards brittleness |
Additives
The main function performed by additives in thermoplastic composites are as under:
Manufacturing of WPC
Extruded WPC profiles are typically manufactured using extrusion process. In the Extrusion process there is a continuous heating, compressing and conveying of raw ingredients that has already been premixed. The extrusion process consists of shaping of the material with the help of extrusion dies, cooling of a product upon its exit from the die and down stream handling including cutting, embossing, sanding and other treatments. This process saves the cost of machining and fabrication. Shape of the final product obtained would be replication of the die opening. The products/profiles made by this process can be cut into small pieces, moulded, routed, sanded etc., with the same tools, feeds and speeds as with wood.
While coming to the extruder type there are variety of equipment available the most common are single-screw extruders, counter-rotating twin-screw extruders or set ups using custom extruders. Out of the three the single-screw system is the cheapest. But typically it has some limitations. Twin-screw extruders on the other hand are good option for extruded woo thermoplastic composites or WPC because here the mixing action is able to blend the wood filler and polymer perfectly in a single process. Along with that it gives low screw speed as well as low-shear mixing, so essential for keeping down the temperatures.
Application of WPC Profile
| Industry | Application |
| Building & Construction | Window and door frames, Cladding |
| Industrial/Infrastructure | Industrial flooring, railings, bulkheads, Railway sleepers etc. |
| Automotive | Door & head liners, interior panels, rear shelves, Truck floors etc |
| Garden/ Outdoor | Decking, Fencing, garden furniture, shelters sheds, playground equipment etc. |
| Interiors and Internal finishes | Interior panels, Office furniture, Kitchen cabinets, shelving, shutters/Blinds etc. |
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WPC Extruded Profiles in Construction Applications Salient Features
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