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Mere miljøvenlige nåleolier til maskinstrikning

Summary and conclusions

The basis for the project was the fact that by industrial machine knitting oils are used for lubricating the moveable parts of the machines. These lubricating oils are normally based on mineral oil and are called needle oils. It is estimated that 20 – 30 tonnes of needle oils are applied to knitted fabrics per year in Denmark, and all of this is expected to end up in the wastewater from the dyehouses. An unknown additional amount comes from imported grey knitted fabric.

Therefore, the purpose of the project was to investigate the possibility of using alternative lubricants, which are less critical regarding the external environment as well as the occupational health and safety. Alternative products were to be identified through literature search, contact to companies, knowledge centres, suppliers and producers. The alternative products were to be tested as well as to be evaluated regarding eco-toxicological and occupational health and safety aspects. Finally suitable products should be tested on normal production machines.

A number of possible alternatives has been identified and evaluated, and the most promising ones have been tested regarding lubricating properties, scourability and degradability. At the same time a supplier has actively undertaken the development of an alternative needle oil during the project period.

The lubrication properties of a number of alternative products have been tested, products based on mineral oil as well as non-mineral oils, and needle oils as well as other lubricants. The results showed that regarding lubrication properties all the tested products could be used, as their lubrication properties were as good as, or better than, the standard product used as a reference.

For some of the products mentioned above the scourability has been investigated, as it is very important that the needle oil can be removed from the knitgoods after knitting. The results showed that none of the alternative products had an immediate scourability in line with the standard product. The scourability would, however, probably be improved by adjusting the emulsifying system used in the product.

The toxicological and eco-toxicological data of the tested alternatives were in general so sparse that it was difficult to characterise the individual products. It was indicated, however, that non-mineral oil based products should be preferred to mineral based products.

The best non-mineral oil based product has in various steps been optimised and tested, both in laboratory scale and on a knitting machine during normal production conditions. Further the updated toxicological and eco-toxicological data has currently been assessed.

The base lubricant in the product has been tested readily biodegradable, and the toxicity towards water living organisms has been tested low, even though it is principally difficult to interpret results for water-insoluble products in aqueous conditions.

Tests at a knitting mill, where the alternative product has been tested during normal production on a knitting machine, demonstrated that the lubrication properties were fully in line with the standard oil, and that no negative effects had occured on the knitting machine.

Finally the scourability of the alternative product has been tested in several steps, and the knitting mill declared it acceptable in its final version. The scourability results were verified by laboratory tests.