Citroflex A-4 alternative: cross-referencing ATBC to Citriflex 84

A specification that calls for Citroflex A-4, or for Citroflex A-4 or equivalent, is calling for acetyl tributyl citrate, ATBC, CAS 77-90-7. Citriflex 84 is acetyl tributyl citrate at 99 percent minimum, supplied from North American stock with FDA and EU 10/2011 food-contact documentation. Cross-references to commonly specified citrate plasticizer grades are available on request.

Looking for a Citroflex A-4 alternative?

The citrate plasticizer category is often named by its best-known trade name, so a drawing or a formulation card will call for Citroflex A-4 where it means ATBC. Citriflex 84 is that material. The goal of a cross-reference is a place on the approved vendor list next to the incumbent, qualified in your own system, so the program has a second source with its own supply chain behind it. Every specification value and every compliance document is stated on the Citriflex 84 grade page.

Why a citrate cross-reference is simpler than a polymer one

ATBC is a single substance, not a formulated product. Two suppliers' acetyl tributyl citrate are the same molecule; what differs between them is the specification they release against and the documentation they can stand behind. So a citrate cross-reference is matched on limits and paperwork rather than on a curve of mechanical properties, and the qualification trial mostly confirms that nothing changed.

The five values that decide a citrate match

• Assay. Citriflex 84 is 99 percent minimum acetyl tributyl citrate. Tributyl citrate, the unacetylated precursor, is controlled as a residual, and a spec that names a minimum assay is matched here first.
• Acid value and color. 0.2 mg KOH/g maximum and 30 Pt/Co maximum. These are the two values that show up in the finished film or compound, as odor and as a tint, so they are the ones to compare against the incumbent's limits.
• Moisture and heating loss. 0.15 percent and 0.2 percent maximum. Moisture matters in cyanoacrylate and isocyanate systems, heating loss in anything processed hot.
• Flash point and handling. 204 degrees C by Cleveland open cup. Not dangerous goods; non-regulated by DOT, IMDG and IATA, in 200 kg steel drums, 1,100 kg IBCs or bulk.
• The documentation set. FDA 21 CFR 172.515, 175.105, 175.300, 175.320, 178.391 and 181.27; EU 10/2011 Annex I as FCM substance 138; EU REACH registration and UK REACH DUIN; heavy metals statement; a restricted substances declaration covering PFAS, nitrosamines, bisphenols and MOSH and MOAH; TSCA active. State the standard you have to meet at the start so the match is made inside the cleared set.

Pharmaceutical variants

Some citrate lines also carry a pharmacopoeia-grade variant for pharmaceutical coatings. Citriflex 84 is released against the industrial specification above and the documentation set that goes with it. If the specification names a pharmaceutical grade, say so at the start, so the conversation begins with what the documentation can and cannot support.

What to send

Four items get a cross-reference moving in one pass: the grade name or data sheet you are working from, the resin system and application, the standard you have to meet, and your current loading. From that we confirm the specification match, provide the TDS and SDS, and send a sample.

Qualifying it

Run the first trial at your current loading, because the molecule has not changed. Check the color of the finished film or compound, the processing window, and whatever migration or extraction test the application already uses. Loading adjustments belong to a switch from a phthalate or another chemistry, which is covered in choosing a non-phthalate plasticizer, not to a switch from one ATBC to another.

Frequently asked

Is Citriflex 84 the same as Citroflex A-4?

Both are acetyl tributyl citrate, CAS 77-90-7, a single substance rather than a formulated product. Citriflex 84 is released against its own specification: 99 percent minimum active, acid value 0.2 mg KOH/g maximum, color 30 Pt/Co maximum, moisture 0.15 percent maximum. Cross-references to commonly specified citrate plasticizer grades are available on request. A cross-reference is a qualified starting point, and the confirmation happens in your own system with a sample.

What information do I send for an ATBC cross-reference?

The grade name or data sheet, the resin system and application, the standard you have to meet, and your current loading. From that we confirm the specification match, send the TDS and SDS, and ship a sample.

Can I switch citrate plasticizer suppliers without reformulating?

Usually, because the molecule is the same. Run the first trial at your current loading and check color, processing and whatever migration or extraction test your application uses.

What documentation comes with Citriflex 84?

Technical data sheet, safety data sheet, certificate of analysis with each lot, TSCA statement, EU REACH registration and UK REACH DUIN certificates, a heavy metals statement, a restricted substances declaration covering PFAS, nitrosamines, bisphenols and MOSH and MOAH, and a food contact compliance statement citing the FDA sections and the EU 10/2011 FCM 138 listing.

Send us the spec

Send the grade name or data sheet you are working from. We will confirm the match, provide the documentation, and get a qualification sample moving. Where the grade is used, with its physical properties and how it compares with tributyl citrate and triethyl citrate, is on Citriflex 84 applications.