First, stearic acid is not divided into rubber grade and food grade~~~ I don’t know where you have seen it. Stearic acid has a qualification certificate for food. If so, please give I'll study.

Stearic acid is divided into primary, secondary and tertiary acids. The primary acid is also called cosmetic grade stearic acid. The tertiary acid is rubber grade stearic acid, which is in between. It is secondary acid. Primary stearic acid can be used in the food industry, such as Span, but there is no relevant national or international certification. It is said that some institutions are working on this.

Then I will explain to you the question about the code name. The code name is just a name and does not have much meaning. 1801, the 18 in the front means C18, and the 01 in the back means first-level acid, but Shuangma and Yihai Specially, it is a third-level acid. Generally, the 1801 imported from abroad is a first-level acid. Of course, not all first-level acids are called 1801, such as 401 and the like. The 1840 you mentioned at the end tells you that it is Yihai's primary acid. The secondary acid is between the two and is used by customers who do not have very high quality requirements, such as mid-range hard salt.

If you want to know specifically what kind of stearic acid you need, the best way is to ask for samples to be tested. Once they pass the test, you can use them. I have imported 15 models of samples with various names. The quality levels vary, so many things can only be learned after encountering them slowly, and you cannot hear or explain them clearly at once.

It seems that there is still an unanswered question, what is the difference between primary acid and tertiary acid? The difference between them is superficially color and smell, and then the nature is iodine value and other insoluble matter, etc., because they Determined by their properties, their application fields and prices are different.

If you don’t understand anything, just ask