I have been busy lately and have been slacking off on my column, but I would like to continue writing as much as possible.
I am sorry that I often start writing on an impulse and never finish.
If there is a topic you would like to know more about or are interested in, please send me an e-mail.
Now, the theme of this issue is alkylnaphthalenes.
Alkyl naphthalenes are expected to improve oxidation stability, prevent hydrolysis, improve thermal stability, and adsorb on metal surfaces to protect engines during dry starts and high loads.
It may be a matter of viscosity index, or it may be especially strong at high temperatures, and we have heard reports of the effect of increased viscosity under high pressure, so much so that it feels harder than the oil of the same number in the high temperature and high load range.
In addition, there is an adsorption effect, but it does not interfere with other additives and is hard to do so.
The demerit is that there seems to be some swelling of packing in old vehicles, but there is no problem if it is not extreme, such as 100% AN. Since PAO has a shrinking effect, it is good to add a small amount to prevent the packing from losing its shape, and it is thought that there is no problem even if it is added to mineral oil.
P.S. I have been using a recommendation of less than 15% for the amount added, depending on what is important,
Although it depends on what is important, we had recommended less than 15%, but it seems that the upper limit of 10% is still safe.
If you are aiming for friction reduction by adsorption effect, it should be around 2-3%, if you are aiming for protection under high load, 3-10%, and if it is more than that, it should be used for racing or industrial machinery to prevent oil deterioration.