Because of the limited thermal stability of wood only thermoplastics
that melt below 200 Deg C are commonly used in WPCs. Currently, most
WPCs are made with PE, both virgin & recycled, for use in exterior
building components. However, WPCs made with wood –PP are typically used
in automotive & consumer products and very recently, these
materials have been investigated for use in building profiles. Wood
filled PVC composites typically used in window manufacture are now being
used in decking as well. Polystyrene & ABS are also being used. The
plastic is often selected based on its inherent properties, product
need, availability, cost and the manufacturer's familiarity with the
polymer.The wood used in WPCs is most often in particulate form (wood
flour) or very short fibers, rather than longer individual fibers.
Products typically contain 50 % wood, although some composites contain
very little wood Composite wood decking.
Others
contain as high as 70 %. The relatively high bulk density & free
flowing nature of wood flour compared with wood fibers or other longer
natural fibers, as well as low cost, and availability, is attractive to
WPC manufacturers and users. Common species used include pine, maple,
& oak. Typical particle sizes are 10 to 80 mesh Wood Plastic Composite Floor.
Since
the early 1990's, the wood – plastic composite industry has grown
significantly. Today, wood & other natural fibers account for 7% of
the total 2.5 billion kgs filler & reinforcement used. This
represents a 135 % increase in natural fiber demand since 1990 with most
of the growth in the past five years. The price of wood is dependant on
the location. Low cost wood in the USA can be attributed to the
considerable amount of wood residues (60 Million metric tones) generated
just from the primary timber processors. The growth of wood flour &
fiber use in thermoplastics has outpaced that of other natural fibers.
Natural fibers are roughly twice as expensive as wood fiber, but are
still well below most other Composite wood plastic.
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