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|
Thermoforming Plastic
| Thermoforming plastic material is commonly used in the form of a
PVC-Acrylic material provided under trade names of Kydex, Royalite, etc.
This material is tough, resistant to impact, but remains relatively soft
(cuts or scratches with a sharp object), and is not used in areas where
it is exposed to high heat.
An alternative construction of the PVC-Acrylic thermoforming material,
uses a polyvinyl fluoride (PVF) (AKA Tedlar®) coating which can be printed
with a variety of patterns. This material is commonly used for aircraft
interiors, is quite durable and easy to clean, however, it is damaged
easily with sharp instruments. |
| Standard: |
ASTM D792 - Standard Test Methods
for Density and Specific Gravity (Relative Density) of Plastics by
Displacement
| | Purpose: |
These test methods describe the determination of the specific
gravity (relative density) and density of solid plastics in forms
such as sheets, rods, tubes, or molded items.
|
|---|
| Criteria: |
Specify standard name, desired specific gravity and tolerance
|
|---|
| Usage: |
ASTM D792, specific gravity XX to XX - (see table below) |
|---|
|
| Standard: |
ASTM D785 - Standard Test Method
for Rockwell Hardness of Plastics and Electrical Insulating Materials
| | Purpose: |
This test method covers two procedures for testing the indention
hardness of plastics and related plastic electrical insulating materials
by means of the Rockwell hardness tester.
|
|---|
| Criteria: |
Specify standard name, Rockwell scale, desired hardness, and tolerance.
|
|---|
| Usage: |
ASTM D785, Rockwell, R-Scale, Hardness XX to XX - (see
table below) |
|---|
|
| |
Thermoplastic Materials Common
Usage Table
| Physical Property
|
Test Method |
Performance Requirement
Value |
| Specific Gravity |
ASTM D792 |
1.20 to 1.36 |
| Hardness, Rockwell |
ASTM D785 |
90 to 100, R-Scale |
| Tensile Strength |
ASTM D638 |
5,500 psi (38 MN/m2) minimum
at 73°F (23°C) |
| Flexural Modulus |
ASTM D790 |
320,000 psi (2206 MN/m2) minimum elasticity at 73°F (23°C) |
| Flexural Strength |
ASTM D790 |
10,000psi (68,947.6 kPa ) minimum at 73°F (23°C) |
| Impact Strength |
ASTM D256 |
6.6 foot pounds per inch of notch minimum (at 73°F notched IZOD)
|
| Heat Shrinkage |
None |
1.5% maximum, 10 minutes @
380°F (193°C) |
| Thickness |
None |
3/32 inch (2.38 mm) minimum
|
Note: other test procedures listed
in the above table, but not shown above, are described in the
FRP section.
|