the difference between synthetics and semisynthetics

[HardCort]

I went to the store for engine oil, I usually fill in 10W40, they began to offer me different manufacturers and say that one is semi-synthetics, and the other is pure synthetics and their price is very different, what does this mean?

[hungry]

The composition of modern Motor oil 10w40 is formed according to the principle of adding additives to the base oil. Fully synthetic 10w-40 oil provides higher viscosity, better oxidation and thermal degradation stability, and helps fight oil deposits. This helps to improve fuel efficiency and can even increase vehicle power by reducing engine drag. 10w-40 semi-synthetic oil has many of the characteristics of a fully synthetic oil, but at a lower cost. This type of oil is composed of a blend of synthetic and conventional base oils, with some additives added to provide additional oxidation stability and excellent low temperature properties. Synthetic blends allow drivers to easily switch from regular oil to synthetic, which is why this type of oil is becoming more and more popular with modern drivers. It is also a great intermediate option for drivers who need the added protection and performance of a synthetic oil, but are not willing to pay to switch completely to a synthetic oil.