Tayfun Yılmaz
General Manager / Engineer MSc.
Vario Engineering and Production Technologies Inc.
It is said that knitting was found by the Central Asian Turks and the Egyptians around the same time in the 5th or 6th century.
With the invention of the latch needle in knitting by Matthew Townsend in 1853, the production of the first knitting machine equipped with this needle in 1867 by the researchers of the following years, and the development of the first circular knitting machine with the same element in 1878, the sound of mechanical knitting in textiles began to be heard.
Knitting machines, new knitting methods and patterns were developed, and therefore the knitting industry improved with the rapid emergence of synthetic fibers and yarns after the World War I.
With a new leap after the World War II, the progress of recent years on both mechanical and electronic basis accelerated the developments in this field, and the method and auto-mechanical-based electronic machinery and knitting technology brought by the last three decades reached its peak.
In the last decade, fully electronic circular knitting machines have started to gain popularity in the market. This leads knitting machine manufacturers to use new technology and to produce machines with faster cycles.
By product groups, knitted fabric exports came after fiber, yarn and woven fabric exports and constituted 15.2 percent of textile and raw materials exports.
One of the most important features sought in a needle and sinker oil is that it does not damage the paint coat or plastic parts of the machine, does not increase the temperature of the machine, does not destroy the coating of power cables or does not affect the control system, protects against corrosion. Every person working in this industry knows that a needle and sinker oil should show high lubrication performance on the machine while having a high level of washable properties.
Expert selected special oils help not only to ensure maximum operating reliability, but also to reduce maintenance costs. When choosing the appropriate oil, all technical and operational parameters, including machine types, product quality as well as price/performance expectations should be taken into account. The additive package, which ensures the quality properties and washability of the knitting and sinker oils mentioned above, constitutes the most important cost factor in a knitting oil. The higher the diversity and effectiveness of the additives are, the higher the difference in their costs will be.
A good oil selection and the usual washing methods used in the finishing process will ensure that the oil stains caused by knitting on the fabric will flow off the fabric in the form of soap.
Lubricants must be correctly designed for components exposed to high speeds, temperatures and vibration, as well as to water, steam, acidic and alkaline solutions. Higher efficiency requires longer equipment life or lower oil consumption.
A lubricant that is developed for the specific application area will always present the minimum number of problems. Every movement in machine parts causes wear; because there is no movement without wear. Choosing and using the lubricant that will minimize this wear will reduce the cost and provide the best efficiency.
Washable property of needle oils means that they can be mixed with water in any way. Additives that provide the ability of oil to mix with water are emulsifiers. They reduce the surface resistance of the oil and allow it to mix with water. The use of such a water-miscible oil in knitting machines producing cotton blended fabrics is important for fabric manufacturers.
To minimize the problems experienced especially in the production of lycra, the oils used in the same lines should have better properties. Knitting oil that contacts with lycra spoils the elasticity of the fabric. The manufacturer, on the other hand, subjects the oily fabrics to a high temperature washing process in order to remove the oil from the fabric; this is an undesirable process as it spoils the elasticity of the fabric and therefore the company experiences both production and time losses. At the same time, due to the lubricating feature of the oil, the company will frequently need to change the needle sinker, which creates many problems in terms of production, time and cost.
What do we expect from knitting oils?
- Effective lubrication for a long time
- Preventing viscosity fluctuations at different temperatures
- No resinification
- Keeping the needle channels clean all the time
- Minimizing vibration and noise in the machine
- Reducing the heat generated by friction in the machine
- Resistant to rust
- Contains rust preventive additives
- Does not damage the machine paint and plastic parts
- Less wear on machine parts
- Having the property of spreading and holding on metal parts
- Ability to be used in all lubrication systems
- Not harmful in terms of physiological and environmental aspects in production
- Prolongs the service life of needles and sinkers by protecting against wear, thus reducing maintenance costs
- Reducing energy and operating costs with low frictional resistance
- Compatibility of electronic control systems with elastane fibers and commonly used sealants and plastics
So, how can we have so many features together and protect the machine, while ensuring that it does not leave stains even by washing with water?
Possible raw materials:
- An additive that does not leave ash and carbon, has extreme pressure and also anti-wear properties, such as Triaryl phosphorothionate / Triphenyl phosphorothionate (TPPT), should be used. It should have having high thermal stability, and should be neutral towards yellow metals, unlike sulfide extreme pressure additives.
- An ashless raw material with amine phosphate mixture, extreme pressure, anti-wear and anti-rust properties should be used.
- A phenolic antioxidant such as 2,6-Di-tert-butyl-4-methylphenol (BHT) should be used.
- An amphiphilic oleic acid derivative, which is used as a water-in-oil emulsifier and corrosion inhibitor, should be used for good washing properties.
- A non-ferrous metal deactivator, which is effective in non-polar base oils containing dimercaptothiadiazole, should be used.
- A particularly effective anti-corrosion additive, which is a semi-ester of succinic acid, with excellent demulsifying properties, should be chosen.
A multipurpose raw material is required to obtain a homogeneous mixture by keeping so many raw materials together and at the same time to easily remove these raw materials of different chemical structure from the fabric.
- A biodegradable, fatty alcohol ethoxylate (2EO) based emulsifier should be chosen, which is stable in hard water, exhibits high solubility in washing, and does not irritate the skin. It should be a low foaming, hydrophobic emulsifier for water-miscible metalworking fluid concentrates with low temperature properties.
