Differences Between PET and Nylon
PET (polyethylene terephthalate) is a strong, stiff engineering plastic with excellent machining characteristics, chemical resistance, and bearing and wear properties. PET is often used for food processing machinery applications where low moisture absorption, low thermal expansion, resistance to staining, or resistance to cleaning chemicals is required.
Nylon is a strong, stiff engineering plastic with outstanding bearing and wear properties. Nylon is frequently used to replace metal bearings and bushings often eliminating the need for external lubrication. Other benefits include a reduction in part weight, less operating noise, and decreased wear on mating parts.
PET Material Characteristics
- Easy to machine
- Good chemical resistance
- Strong and stiff
- Easy to fabricate
- Good dimensional stability
- Good for friction and wear
- Stain resistance
- Good for bearings
PET Applications:
- Food processing machinery components
- Valve components
- Manifolds
- Filler pistons
- Bearings and bushings
- Wear pads
- Packaging and machinery parts
- Wheels and rollers
PET Common Brands
- Sustadur PET, TECAPET™ PET, Ertalyte®
Nylon Material Characteristics
- Easy to machine
- Good chemical resistance
- Strong and stiff
- Easy to fabricate
- Good dimensional stability
- Good for friction and wear
- Good electrical insulation
- Prototyping
- Good for bearings
Nylon Applications:
- Bearings and bushings
- Gears
- Wear pads
- Packaging machinery parts
- Food processing machinery parts
- Wheels
- Rollers
- Seals and gaskets
Nylon Common Brands
- SUSTAMID®, TECAMID®, NYCAST®
Typical properties of PET vs. NYLON
| |
UNITS |
ASTM TEST |
PET |
NYLON |
| Specific gravity (73°F) |
|
D792 |
1.38 |
1.14 |
| Tensile strength (73°F) |
psi |
D638 |
11,500 |
12,400 |
| Tensile elongation (73°F) |
% |
D638 |
70 |
90 |
| Flexural modulus of elasticity (73°F) |
psi |
D790 |
400,000 |
410,000 |
Hardness
Rockwell M&R, Durometer Shore D (73°F) |
scale as noted |
D785,
D2240 |
M93, R125, Shore D 87 |
M85, R121, Shore D 80 |
| Izod impact (notched, 73°F) |
ft-lbs/in |
D256 |
0.7 |
1.2 |
| Coefficient of Friction |
|
Dynamic |
0.25 |
0.28 |
| Coefficient of linear thermal expansion |
in/in/°Fx10-5 |
D696 |
3.9 |
4.5 |
| Heat deflection temperature @ 66 psi/264 psi |
°F |
D648 |
240 175 |
- 194 |
| Maximum continuous service temperature in air |
°F |
|
230 |
210 |
| Water absorption (immersion 24 hours) |
% |
D570 |
0.10 |
1.20 |
Values may vary according to brand name. Please ask your Curbell Plastics representative for more specific information about an individual brand.