How do you evaluate TOFA quality? A guide to reading specification sheets and CoAs

Quality is not settled by the product name but by four things: whether each line is a guaranteed limit or a typical value, the test method behind it, whether the per-lot certificate of analysis actually reports those lines, and how close consecutive lots run to the limit. Evaluate in that order.

Which line on a specification sheet actually decides?

A TOFA specification sheet is a short document, and the lines do not carry equal weight. Start the evaluation not with which number looks better, but with which line closes a risk on your line. The table below reorders the limits of the two grades in the KORKİMYA portfolio around that decision logic:

The practical reading: in an application with low colour and rosin acid sensitivity, the max 3% rosin acid limit of TOFA 180 is already sufficient and paying for a tighter limit is unnecessary. On a line where colour stability is critical, the max 2% limit is not a comfort but a requirement.

How do you tell a guaranteed limit from a typical value?

This is the most frequently skipped point in reading a specification sheet. A line written with "min" or "max" is a committed limit and gives you grounds for rejection. A line written as a single number is usually a typical analysis result and does not carry the same weight.

The same product family gives a concrete example. TOFA 180 and TOFA 185 are defined by limits: acid value min 180 and min 185, unsaponifiables max 6% and max 4%. TOFA Rich Distillate, by contrast, is described with single values: acid number 178.5, saponification number 184, unsaponifiables 5.2%, total rosin acids 20.4. The second type of sheet is not wrong, it is a different thing: it shows a composition profile, not an acceptance criterion. You have to write the acceptance criterion yourself.

• Does every line carry a min, a max or a range? If not, do not use that line as an acceptance criterion.
• If a number stands alone, ask the supplier: is this a guaranteed limit or a typical value?
• If a parameter given as a typical value is critical for you, have your own limit written into the order.
• Confirm the direction of each limit: acid value is a floor, while rosin acid and unsaponifiables are ceilings.

Why is a line without a method reference risky?

The same parameter measured by different methods gives different results. If a specification line carries no method, there is no reference to settle whose laboratory is right in a dispute. On the TOFA side the expected method set is narrow and clear: acid value by ASTM D1980, iodine value by ASTM D5768, rosin acid content by ASTM D1240, unsaponifiables by ASTM D1065.

For other items in the family the method set changes, which is normal; what matters is that the method is written on the document. On softwood CTO, for instance, rosin acids are reported by TUR-T 14, acid number by TUR-T 11, residual soap number by PCTM 13, water content by volumetric Karl Fischer (PCTM 4C) and kinematic viscosity at 50 °C by EN ISO 3104, while PQ-restricted metals (Ca, Fe, K, Mg, Na, Mn) are checked by XRF. A TOFA sheet without ASTM references, or a CTO sheet without these methods, is incomplete.

What must a certificate of analysis show?

The specification sheet tells you what the product should be; the certificate of analysis tells you what the batch shipped to you actually is. Build your qualification file on the second. What to look for on a CoA:

1. Lot or batch number and the date of measurement; if it is unclear which shipment the certificate belongs to, the document is useless.
2. Measured values shown next to the specification limit: a bare statement of conformity is not enough.
3. A method reference for every line (on TOFA: ASTM D1980, D5768, D1240, D1065).
4. The appearance line: it is the visible consequence of the distillation cut and the first warning on colour-sensitive lines.
5. Identity: CAS 61790-12-3 and the grade name for TOFA. Note that Turkish documents also call the product "Çam Yağı Yağ Asitleri 180/185".

On the KORKİMYA side this set is standard: TOFA 180 and TOFA 185 are delivered with a per-lot certificate of analysis, KKDIK registration and a Turkish Safety Data Sheet (SDS).

How do you prove lot-to-lot consistency?

A single CoA proves a lot, not a supplier. A product that constantly hugs the limit and one that runs comfortably inside it look identical on paper but do not behave identically on your line. To see consistency, spread the evaluation over time:

• Ask for the CoAs of several consecutive lots and look at where the acid value and rosin acid lines sit relative to the limit.
• Verify the sample in your own laboratory with the same methods and record the gap between your result and the CoA.
• Test the first commercial shipment the same way after sample approval; qualification does not end with the sample.
• Track shelf life: 12 months for TOFA 180 and TOFA 185, extendable to 24 months with quality control testing. The extension is made by testing, not by assumption.
• Verify storage: 20-40 °C, closed containers, carbon or stainless steel tanks. Stock kept outside those conditions can look like a supplier-side deviation.

What changes when you compare against another product in the family?

The evaluation is often not between two TOFA suppliers but between TOFA and another fraction from the same line, and then the sheets do not speak the same language. In the DTO grades rosin acid is deliberately kept high (max 40% in the industrial grade, max 30% in the mid-high and premium grades) and the saponification number is reported as a separate line (min 170 to min 175). A TOFA sheet has no saponification number line, because the product is already the fatty acid fraction.

So compare on acceptance criteria rather than line by line: decide which parameter is a limit for you and which is information. Otherwise the sheet that reports more lines looks unfairly higher in quality.