What is PET?
Polyethylene terephthalate (PET) is a type of semi-aromatic Polyester. PET plastic is a thermoplastic commonly known under the brand name Ertalyte®. It is a naturally colourless and semi-cristalline material.
The most widely used polyester, PET plastic is readily available and relatively inexpensive.
It is a tough, dimensionally stable plastic that offers excellent wear resistance and mechanical strength. It is often reinforced with glass fibers or compounded with silicates or graphite in engineering applications to improve strength and rigidity.
PET has very good machinability and therefore there are few restrictions to consider when machining.
Sharp cutting tools are recommended to avoid chipping during machining.
You may also see PET/Polyester referred to as:
- Trade names: Ertalyte® PET-P (virgin grade), Ertalyte® TX (bearing grade), TECAPET®, TECADUR PET®, LUMEX®, Vivak®, Axpet®, ArniteTM, Rynite®, Impet®, Polyclear® Crystal™, Petra®, ValoxTM
- Poly(oxyethyleneoxyterephthaloyl), Poly[(ethane-1,4-diol)-alt-(terephthalic acid)]
- PETP / PET-P
- PETE
- PETG
- PET ZX
Main attributes
- Relatively high density polyester
- High strength
- High hardness and rigity
- Exceptionally high strength to weight ratio
- Good creep resistance, even at elevated temperatures
- Extremely low moisture absorption
- Outstanding dimensional stability
- Good temperature stability
- Good dimensional stability
- Good chemical resistance
- Good adhesion and welding ability
- Excellent wear resistance
- Excellent stain resistance
- Good electrical insulating properties
- Good resistance to high energy radiation
- Food (FDA) compliant
- Very good heat and heat ageing resistance
- Can be used at temperatures from -20 °C to +115 °C
- Shatterproof
- Recyclable
Common Applications
- Structural components
- Gears & driveshafts
- Electrical components
- Wear parts & rings
- Bearings & bushings
- Machine parts & cases
- Handles
- Computer & appliance housings
UK stock sizes
Here are some indicative stock sizes/colours for PET in the UK. Please note we do not supply stock material, the information provided is purely for design and research purposes.
Example PET Stock Sizes
Stock sizes will vary depending on supplier. Please get in contact to discuss further.
PET is typically available in rod and plate form in lengths of 1000mm and 3000mm.
PET Rod
- From 10mm to 30mm
- Natural / White / Black / Grey
PET Plate
- From 8x500mm to 60x1000mm
- Natural / White / Black / Grey
Please note: some sizes may be non-stocked items and subject to minimum order quantities.
Technical properties
Here are the properties for TECADUR PET natural and Ertalyte® which are unfilled and unmodified PET polyester brands. Reinforced and modified grades will have different properties.
TECADUR PET Properties
Mechanical properties
| Mechanical Properties | Value | Parameter | Norm | Notes |
| Modulus of Elasticity (tensile test) | 3300 MPa | 1mm/min | DIN EN ISO 527-2 | For tensile test: specimen
type 1b |
| Tensile Strength | 91 MPa | 50mm/min | DIN EN ISO 527-2 | |
| Tensile Strength at Yield | 91 MPa | 50mm/min | DIN EN ISO 527-2 | |
| Elongation at Yield | 4% | 50mm/min | DIN EN ISO 527-2 | |
| Elongation at Break | 14% | 50mm/min | DIN EN ISO 527-2 | |
| Flexural Strength | 134 MPa | 2mm/min, 10 N | DIN EN ISO 178 | For flexural test: support span 64mm, norm specimen |
| Modulus of Elasticity (flexural test) | 3400 MPa | 2mm/min, 10 N | DIN EN ISO 178 | |
| Compression Strength | 21/38/89 MPa | 1% / 2% / 5% 5mm/min, 10 N | EN ISO 604 | Specimen 10x10x10mm |
| Compression Modulus | 2800 MPa | 5mm/min, 10 N | EN ISO 604 | Specimen 10x10x50mm |
| Impact Strength (Charpy) | 150 kJ/m2 | max. 7.5J | DIN EN ISO 179-1eU | For Charpy test: support span 64mm, norm specimen |
| Ball Indentation Hardness | 194 MPa | | ISO 2039-1 | Specimen in 4mm thickness |
Thermal properties
| Thermal Properties | Value | Parameter | Norm | Notes |
| Glass Transition Temperature | 81°C | | DIN EN ISO 11357 | Found in public sources |
| Melting Temperature | 244°C | | DIN EN ISO 11357 | |
| Service Temperature | 170°C | short term | | Found in public sources. Individual testing regarding application conditions is mandatory |
| Service Temperature | 110°C | long term | | |
| Thermal Expansion (CLTE) | 8 10-5 K-1 | 23-60°C, long | DIN EN ISO 11359-1;2 | |
| Thermal Expansion (CLTE) | 10 10-5 K-1 | 23-100°C, long | DIN EN ISO 11359-1;2 | |
Electrical properties
| Electrical Properties | Value | Norm |
| Specific Surface Resistance | 1014 Ω | DIN IEC 60093 |
| Specific Volume Resistance | 1014 Ω*cm | DIN IEC 60093 |
Other properties
| Other Properties | Value | Parameter | Norm | Notes |
| Water Absorption | 0.02 / 0.03% | 24h / 96h (23°C) | DIN EN ISO 62 | Ø ca. 50mm, h=13mm |
| Resistance to hot water/bases | - | | - | Poor resistance |
| Flammability (UL94) | HB | Corresponding to | DIN IEC 60695-11-10 | Corresponding means no listing at UL (yellow card). The information might be taken from resin, stock shape or estimation. Individual testing regarding application conditions is mandatory. |
| Density | 1.39 g/cm3 | | | |
Ertalyte Properties
+ values referring to dry material
++ values referring to material in equilibrium with the standard atmosphere 23°C / 50% RH (mostly derived from literature)
General properties
| General Properties | Value | Test Methods | Notes |
| Density | 1.39 g/cm3 | ISO 1183-1 | |
| Water absorption after 24/96h of immersion in water of 23°C | 6 / 13 mg 0.07 / 0.16% | ISO62 | According to method 1 of ISO 62 and done on discs Ø 50mm x 3mm |
| Water absorptioin at saturaion in air of 23°C / 50 % RH | 0.25% | | |
| Water absorption at saturation in water of 23°C | 0.50% | | |
Thermal properties
| Thermal Properties
(The figures gien for these properties are for the most part derived from raw material supplier data and other publications) | Value | Test Methods | Notes |
| Melting Temperature (DSC, 10°C/min) | 245°C | ISO 11357-1/-3 | |
| Glass Transition Temperature (DSC, 20°C/min) | - | ISO 11357-1/-2 | Values for this property are only given here for amorphous materials
and not for semi-crystalline ones |
| Thermal Conductivity at 23°C | 0.29 W/(K.m) | - | |
| Coefficient of linear thermal expansion - average value between 23 and 60°C | 60 x 10-6 m/(m.K) | - | |
| Coefficient of linear thermal expansion - average value between 23 and 100°C | 80 x 10-6 m/(m.K) | - | + |
| Temperature of deflection under load: method A: 1.8 MPa | 80°C | ISO 75-1/-2 | |
| Maximum allowable service temperature in air: for short periods | 160°C | - | Only for short time exposure (a few hours) in applications where no ro only a
very low load is applied to the material |
| Maximum allowable service temperature in air: continuiously for 5,000/20,000h | 115/100°C | - | Temperature resistance over a period of 5000/2000 hours. After these periods of time, there is a decrease in tensile strength - measured at 23°C - of about 50% as compared with the original value. The temperature values given here are thus based on the thermal-oxidative degredation which takes place and causes a reduction in properties. Note, hwoever, that the maximum allowable service temperature depends in many cases essentially on the duration and the magniture of the mechanical stresses to which the material is subjected. |
| Minimum service temperature | -20°C | - | Impact strength decreasing with decreasing temperature, the minimum allowable service temperature is practically mainly determined by the extent to which the material is subjected to impact.The value given here is based on unfavourable impact conditions and may consequently not be considered as being the absolute practical limit. |
| Flammability: Oxygen Index | 25% | - | |
| Flammability: according to UL 94 (3/6mm thickness) | HB/HB | ISO 4589-1/-2 | |
Mechanical Properties at 23°C*
| Mechanical Properties at 23°C* | Value | Test Methods | Notes |
| Tensile Stress at yield / Tensile Stress at Break | 90 / - MPa | ISO 527-1/-2 | +/++
Test speed:50mm/min [chosen acc. to ISO 10350-1 as a function of the ductile behaviour of the material (tough or brittle)] |
| Tensile Strength | 90 MPa | ISO 527-1/-2 | +
Test speed:50mm/min [chosen acc. to ISO 10350-1 as a function of the ductile behaviour of the material (tough or brittle)] |
| Tensile Strain at Yield | 4% | ISO 527-1/-2 | +
Test speed:50mm/min [chosen acc. to ISO 10350-1 as a function of the ductile behaviour of the material (tough or brittle)] |
| Tensile Strain at Break | 15% | ISO 527-1/-2 | +/++
Test speed:50mm/min [chosen acc. to ISO 10350-1 as a function of the ductile behaviour of the material (tough or brittle)] |
| Tensile Modulus of Elasticity | 3500 MPa | ISO 527-1/-2 | +/++
Test speed: 1mm/min |
| Compression test: compressive stress at 1 / 2 / 5% nominal strain | 33/64/107 MPa | ISO 604 | +
Test speed: 1mm/min
Test specimens: cylinders Ø 8mm x 16mm |
| Charpy impact strength - Unnotched | 50 kJ/m2 | ISO 179-1/1eU | +
Pendulum used: 4 J |
| Charpy impact strength - Notched | 2 kJ/m2 | ISO 179-1/1eA | + |
| Ball indentation hardness | 170 N/mm2 | ISO 2039-1 | +
Measured on 10mm thick test specimens (discs), mid between centre and outside diameter |
| Rockwell hardness | M 96 | ISO 2039-2 | +
Measured on 10mm thick test specimens (discs), mid between centre and outside diameter |
* The figures given for the properties of dry material (+) are for the most part average values of tests run on test specimens machined out of rods Ø 40 - 60mm. Except for the hardness tests, the test speciments were then taken from an area mid between centre and outside diameter, with their length in longitudinal direction of the rod (parallel to the extrusion direction).
Considering the very low water absorption of Ertalyte, the values for the mechanical and electrical properties of this material can be considered as being practically the same for dry (+) and moisture conditioned (++) test specimens.
Typical chemical composition
The chemical formula of PET is (C10H8O4)n
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