| Coextrusion: |
A method whereby two or more polymer compounds
are extruded by two or more extruders into a common die to produce
a finished product. Coextrusion allows a manufacturer more flexibility
in combining and maximizing different desirable qualities into
one product profile. Such combined qualities may not be available
through the simpler mono-extrusion method. The combined layers
are “chain entangled” by polymer chains to form an
inseparable product. The “layers” cannot be physically
separated in the final product. Both the capstock (outer layer)
and the substrate (inner layer) must be made of similar materials,
in this case PVC.
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| Mono-extrusion: |
In use since the
late 1930’s, mono-extrusion means
a single compound is extruded by a single extruder. |
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| Extruder: |
The machine used to create extruded products. An
extruder melts the raw material then pushes the melted
material through a die while a
pull is applied to the exit point of the die. Many
common materials are created through an extrusion process. |
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| Die: |
The device, often called the die head, that molten
material passes through during extrusion giving the desired
shape to the materials being extruded. |
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| Profile: |
A shape other than
round shapes produced using an
extruder. |
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| Polyvinyl Chloride (PVC): |
A combination of petroleum
by-products and salt. Other ingredients are added to
PVC to improve
weatherability, impact resistance and durability. |
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| Compounding: |
Process of adding ingredients to a raw material
(PVC in this case) to change the performance of the final product.
The final product typically contains about 80% PVC and is homogenous
(uniform throughout). |
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| Impact Modifiers: |
Ingredients added to the extrusion raw materials
to absorb “impacts” in extreme weather conditions
(Heat & Cold). |
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| Light Stabilizers: |
Ingredients added to the extrusion raw materials
to prevent fading and chalking. UV light from the sun causes
fading (dulling of a surface). White residue, chalking, forms
when titanium dioxide is released from a finished product. Light
stabilizers reduce the amount of titanium dioxide needed and
help prevent chalking. |
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| Stabilizers: |
To prevent degradation during the extrusion process
and from solar heating, heat stabilizers are added to the PVC
material.
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| Titanium Dioxide (TIO2): |
A critical ingredient added to PVC formulations
to give it better UV protection. TIO2 aids in the reflection
of UV rays thus preventing the build up of heat and protecting
from solar fading, cracking, breaking and color loss.
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| Ultraviolet (UV) Inhibitors: |
Ultraviolet (UV) Inhibitors: Ingredients added
to protect PVC from the damaging rays of the sun. TIO2 is the
most important and common UV inhibitor. |
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| Weatherability |
Weatherability is achieved through the
exacting science of using all of the correct ingredients and is
not just limited to high-level of TIO2 and heat stabilizers.
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