PUR and PVC cables and wires
When we think of industrial production lines or stationary drives, automatic lubricating points are indispensable in any mechanically moving machine. Almost all applications are electronically monitored and are wired. In CNC milling machines, for example, litres of cutting and cooling oils flow which inevitably come into contact with the cables and wires and sometimes even submerge them for longer periods. The following sections find out what is important to you when using cables in oily environments.
What is meant by oil resistance?
Oil resistance refers to the resistance of materials to the effects of oils such as synthetic oils. A material that is resistant or insensitive to oil does not suffer any damage if it comes into contact with oil for a short time or over an extended period.
What are oil-resistant cables?
In the case of oil-resistant cables, the materials used in the plastic outer sheath will not have a chemical reaction with oils. For a cable to be considered oil-resistant, the properties of the plastics must remain unchanged despite temporary or permanent contact with oil. Examples of oil-resistant plastics are fluoropolymers or polyurethanes (PUR). PVC cables are only oil-resistant if special chemical additives are added to the polyvinyl chloride outer sheath.
Which factors influence the oil resistance of a cable?
A number of factors must be taken into consideration when selecting the right material for the plastic outer sheath:
What oil temperature is the cable exposed to?
How long does the cable come into contact with the oil?
Depending on the application requirements, cables are divided into different classes
The test methods for the individual classes are defined by standards
- Class 1: No oil resistance
Contact of the outer sheath with oils results in damage to the cable. Cables in this class are suitable for use in oil-free environments.
- Class 2: Oil-resistant according to DIN EN 50290-2-22 (TM54)
- Class 3: Oil-resistant according to DIN EN 50363-4-1 (TM5)
- Class 4: Oil-resistant according to DIN EN 50363-10-2
When is a cable considered oil-resistant?
To avoid damage caused by oil, all components of the system must be oil-resistant. This requires both the cable sheath and all connectors or cable glands to be oil-resistant.
If this is not the case, oils cause the plastics to swell or become brittle. This means that non-oil-resistant plugs or glands would simply flake off or even fall off. The outer sheath of the cable would lose its protective effect and, in some circumstances, the cable would fail completely.
How do I identify oil-resistant LAPP products?
At LAPP, we test our cables in accordance with recognised German, European and international standards. Standardised test oils are used to test and confirm the oil resistance of cables and wires.
Oil-resistant LAPP products can be identified in our oil drum pictogram as an indicator of products with increased oil resistance. Products with a "PUR" outer sheath", which are always oil-resistant due to their material properties, are also labelled with the product designation "P". For example, our product ÖLFLEX® CLASSIC 400 P, a cable with increased chemical resistance.
Where are oil-resistant wires and cables used?
Cutting and cooling oils are used in component production in industry for temperature control and tool conservation. This means that cables, connectors or cable glands used to connect the actuators and sensors in the system are permanently or temporarily exposed to various oils.
Oil-resistant LAPP products are resistant to lubricating, cutting and cooling oils, chemical cleaning agents and hot water, making them ideally suited to many industrial applications in production or production.
For example, our oil-resistant SKINTOP® cable glands have a long-term resistance to various oils. This means that your cable gland remains functional even after an extended period of use in oil, does not ripple or fall.
For special applications, e.g. in a CNC processing centre, cables also have to be permanently laid in oil or resistant to hot cooling lubricant. An oil-resistant outer sheath of the cable ensures a functioning connection with low risk of failure in the long term.
Not all oils are alike
How does that affect the selection of cables and wires?
Depending on the application, oils can differ greatly in their chemical composition. The standardised test oils used for the conventional tests, which are usually based on mineral oil, cover many areas of application, but cannot represent every possible composition. Therefore, at LAPP we offer you the opportunity to check whether the selected product is also resistant to the special oil you use. Talk to our experts about this.
Fluoropolymers and Teflon are all-purpose weapons against almost all oils in the cable industry. Often, resistance to very special oil can only be guaranteed with cables whose plastic is made from these materials. Our products ÖLFLEX® HEAT 205 and ÖLFLEX® HEAT 260 at LAPP offer you the perfect solution for use with special oils.
Other important and oil-compatible outer sheath materials can be found in the table below:
Insulation material: PU
Cables with a PU outer sheath offer a high oil-resistance and are also very notch-resistant.
PUR outer sheaths are therefore frequently used in plant and mechanical engineering. The polyurethane (PU) sheathing remains flexible even in continuous use, withstands high mechanical stress and is also resistant to many chemicals and oils.
Due to its oil and torsion resistance, our ÖLFLEX® ROBOT 900 P is ideally suited to robot applications with dynamic bending and torsional movements.
Insulation material: PVC
Cables with a PVC outer sheath are not particularly resistant to oil in their usual chemical composition.
But here too, no rule without exception applies. At LAPP, we offer you products with a PVC outer sheath that offer you the benefits of a PVC cable while also being oil resistant thanks to special chemical additives.
Of particular note is our ÖLFLEX® 191, an oil-resistant and flexible PVC cable for the European and North American markets.
Insulation material: TPE
In addition to UV resistance,thermoplastic elastomers (TPE), which also include thermoplastic polyurethane (TPE-U) or PU, also offer a high level of oil and bio-oil-resistance. Compared to PU, however, a cable with a TPE outer sheath usually stands out due to its higher UV-resistance and other temperature ranges.
For example, our ÖLFLEX® ROBUST FD C control cables with a TPE sheath are available for use in cable chains and in harsh conditions.
Which oil-resistant products does LAPP offer in addition to cables and wires?
Depending on the application area, the following oil-resistant products are also available from LAPP:
Oil-resistant cables are not sufficient if the drag chain in which they are located cannot have this property. Oil-resistant cable chains are particularly essential in linear moving machinery and systems used in oily environments. To find the right cable chain for your application, you can get support from the ÖLFLEX® CONNECT CHAIN configurator.