Lubrication of elastomers

Talk to the specialists sooner rather than later
Lubrication of elastomers: how design and R&D can benefit from Klüber’s consultancy practices
Published in ke konstruktion + engineering, June 2003

A particularly tricky design task is the lubrication of elastomer components. konstruktiv + engineering talked to two experts at Klüber Lubrication in Munich about this topic. An issue that came up again and again during this discussion was the choice between wet and dry lubrication solutions.

Industrial products contain all kinds of elastomers. They are, for instance, used as the base material when making seals or moulded components. Frequently they contain plasticisers, stabilisers or other additives chosen to optimise their material and product characteristics.

But one difficulty remains: the tribological behaviour of elastomer materials as such is not sufficient for many static, quasi-static and especially dynamic applications. Without additional lubrication, the components wouldn't last for long and would suffer irreversible damage. To prevent this from happening, designers, tribologists and lubricant development engineers must work on the lubrication of elastomer components from an early stage. If know-how in tribology is lacking in the component manufacturer's team, lubrication specialists should be contacted as early as possible. "Lubricants are at least as important as design elements as all the other materials in a technical component," remarks Helmut Seubert of Klüber Lubrication. Consequently, they should be given no less attention.

A wide variety of formulations
When dealing with this subject, one quickly learns that there is a wide range of different elastomers: For instance there are acrylate rubbers (ACM), ethylene-propylene-diene rubbers (EPDM) and nitrile rubbers (NBR), just to name a few. And this gives of course rise to one question, which we do not want to leave unasked, even though it may seem a little naive: Is there a universal lubricant that can be equally used for all or nearly all different types of elastomers? The answer by Helmut Seubert, product manager at Klüber Lubrication, came as was to be expected: "No, there isn't. In a tribo-system, all components must be individually designed bearing in mind how they will operate in combination. This applies to elastomers as well as any metal parts they are in contact with, and of course to the lubricant as well. Even when we have only NBR materials, one is not necessarily like the other, there are many different formulations. So it is only logical that there is no single 'cure' for all applications."

Under tribological aspects, elastomers pose a special challenge to everybody involved in the design task. According to our Klüber experts there is, at the same time, no straightforward answer to the question which type of elastomer is a particularly tough nut to crack for the lubricant supplier. "What can be said, though, is that it is normally the covalent rubber-elastic materials that really require a lot of know-how." For non-chemists, this means elastomers that don't get along well with hydrocarbon compounds, i.e. mineral oil products, petrol, etc., because they make them swell, shrink, or else their tensile strength or ductility dwindle.

But things look different again when it comes to dry lubrication: here, most difficulties may be found with a totally different set of elastomers. Marion Punke, Head of Marketing/Product Management, has a lot of experience in technical applications, and explains: "When asked about which types of elastomer are the most critical, we must differentiate depending on whether we are talking about wet or dry lubrication."

Bonded coatings call for a different view
Dry lubrication solutions such as bonded coatings require us to look at elastomer lubrication from a different angle. The coating's adhesion to the material is a decisive aspect if satisfactory performance is to be obtained. In this context, it is silicone materials that tend to prove the most problematic.

For any design engineer having to find a solution for an elastomer lubrication task, Klüber is certainly a good address to turn to. Helmut Seubert paints the picture: "Basically, we have a lubricant for every material in our portfolio. But with every application there are a few vital questions that need to be answered, namely in what kind of application are the materials used, and what are the other factors prevailing in the tribosystem. One question that should be dealt with well in advance is how the elastomer material was manufactured. It is important to know, for example, if a transformation agent or other auxiliary substances like antioxidants were used which may have migrated to the component surface where they might cause trouble."

Seeing the complexity of all these questions, it is only natural that the Klüber team appreciates being involved in the design and development process from an early stage. In reality, however, this normally happens only after massive problems have already emerged, much to the regret of Marion Punke. Helmut Seubert adds: "While a component is still in the development stage, we can offer our mechano-dynamic test bay to carry out tests under conditions resembling the component's future application. And since we cooperate closely with seal manufacturers, for example Freudenberg, we can come up with optimal solutions in a very short time."

The product portfolio of the Munich company comprises more than 2000 different special lubricants. And if the right solution for a specific application is not among them, a new lubricant will be developed tailored to the user's needs. This does not necessarily involve large volumes, explains Marion Punke: "Take a bonded coating that is to be applied to an O-ring seal. Here we're talking about quantities of 0.01 grams! So in this context our primary motivation is to keep pace with current trends, to make sure we have a solution in store for the applications of today and tomorrow." And Marion Punke continues: "Dry coating of O-rings is definitely on the rise in the automotive industry, and a similar tendency is recognisable in the food-processing sector." The reason behind this trend is the wish to prevent O-rings from gluing together, which is something dry lubrication guarantees.

Click here to see test results of Klüber lubricants with different elastomers...

Click here to contact us for more information...



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						Talk to the specialists sooner rather than later Lubrication of elastomers: how design and R&D can benefit from Klüber’s consultancy practices Published in ke konstruktion + engineering, June 2003 A particularly tricky design task is the lubrication of elastomer components. konstruktiv + engineering talked to two experts at Klüber Lubrication in Munich about this topic. An issue that came up again and again during this discussion was the choice between wet and dry lubrication solutions. Industrial products contain all kinds of elastomers. They are, for instance, used as the base material when making seals or moulded components. Frequently they contain plasticisers, stabilisers or other additives chosen to optimise their material and product characteristics. But one difficulty remains: the tribological behaviour of elastomer materials as such is not sufficient for many static, quasi-static and especially dynamic applications. Without additional lubrication, the components wouldn't last for long and would suffer irreversible damage. To prevent this from happening, designers, tribologists and lubricant development engineers must work on the lubrication of elastomer components from an early stage. If know-how in tribology is lacking in the component manufacturer's team, lubrication specialists should be contacted as early as possible. "Lubricants are at least as important as design elements as all the other materials in a technical component," remarks Helmut Seubert of Klüber Lubrication. Consequently, they should be given no less attention. A wide variety of formulations When dealing with this subject, one quickly learns that there is a wide range of different elastomers: For instance there are acrylate rubbers (ACM), ethylene-propylene-diene rubbers (EPDM) and nitrile rubbers (NBR), just to name a few. And this gives of course rise to one question, which we do not want to leave unasked, even though it may seem a little naive: Is there a universal lubricant that can be equally used for all or nearly all different types of elastomers? The answer by Helmut Seubert, product manager at Klüber Lubrication, came as was to be expected: "No, there isn't. In a tribo-system, all components must be individually designed bearing in mind how they will operate in combination. This applies to elastomers as well as any metal parts they are in contact with, and of course to the lubricant as well. Even when we have only NBR materials, one is not necessarily like the other, there are many different formulations. So it is only logical that there is no single 'cure' for all applications." Under tribological aspects, elastomers pose a special challenge to everybody involved in the design task. According to our Klüber experts there is, at the same time, no straightforward answer to the question which type of elastomer is a particularly tough nut to crack for the lubricant supplier. "What can be said, though, is that it is normally the covalent rubber-elastic materials that really require a lot of know-how." For non-chemists, this means elastomers that don't get along well with hydrocarbon compounds, i.e. mineral oil products, petrol, etc., because they make them swell, shrink, or else their tensile strength or ductility dwindle. But things look different again when it comes to dry lubrication: here, most difficulties may be found with a totally different set of elastomers. Marion Punke, Head of Marketing/Product Management, has a lot of experience in technical applications, and explains: "When asked about which types of elastomer are the most critical, we must differentiate depending on whether we are talking about wet or dry lubrication." Bonded coatings call for a different view Dry lubrication solutions such as bonded coatings require us to look at elastomer lubrication from a different angle. The coating's adhesion to the material is a decisive aspect if satisfactory performance is to be obtained. In this context, it is silicone materials that tend to prove the most problematic. For any design engineer having to find a solution for an elastomer lubrication task, Klüber is certainly a good address to turn to. Helmut Seubert paints the picture: "Basically, we have a lubricant for every material in our portfolio. But with every application there are a few vital questions that need to be answered, namely in what kind of application are the materials used, and what are the other factors prevailing in the tribosystem. One question that should be dealt with well in advance is how the elastomer material was manufactured. It is important to know, for example, if a transformation agent or other auxiliary substances like antioxidants were used which may have migrated to the component surface where they might cause trouble." Seeing the complexity of all these questions, it is only natural that the Klüber team appreciates being involved in the design and development process from an early stage. In reality, however, this normally happens only after massive problems have already emerged, much to the regret of Marion Punke. Helmut Seubert adds: "While a component is still in the development stage, we can offer our mechano-dynamic test bay to carry out tests under conditions resembling the component's future application. And since we cooperate closely with seal manufacturers, for example Freudenberg, we can come up with optimal solutions in a very short time." The product portfolio of the Munich company comprises more than 2000 different special lubricants. And if the right solution for a specific application is not among them, a new lubricant will be developed tailored to the user's needs. This does not necessarily involve large volumes, explains Marion Punke: "Take a bonded coating that is to be applied to an O-ring seal. Here we're talking about quantities of 0.01 grams! So in this context our primary motivation is to keep pace with current trends, to make sure we have a solution in store for the applications of today and tomorrow." And Marion Punke continues: "Dry coating of O-rings is definitely on the rise in the automotive industry, and a similar tendency is recognisable in the food-processing sector." The reason behind this trend is the wish to prevent O-rings from gluing together, which is something dry lubrication guarantees. Click here to see test results of Klüber lubricants with different elastomers... Click here to contact us for more information...

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	Marion Punke: "Quite often customers ask us for written confirmation that spare parts kept in the stock won't change tribologically even after many years. Such requirements will keep any engineer's mind busy!"



	Helmut Seubert: "The lubricant is not some little add-on but a vital design element."