Coating Formula Terminology

Quick definitions for "pre-cat," "conversion varnish," et cetera. November 11, 2006

I'm from Glasgow in Scotland and have been employed as a technical support rep for a large Italian wood finish manufacturer for the past 5 years. I often read these pages and am not ashamed to admit that some of the best advice I've given has been learned here.

However, I do sometimes struggle with the North American terminology which is used in the descriptions of certain coatings and would appreciate it if anyone would explain what the following terms mean:
Post cat (Is this the ureic, acid cured product like pre-cat but in 2k form, commonly known as A/C in Europe?)
Conversion (Huh?)

Forum Responses
(Finishing Forum)
From contributor F:
Post cat refers to post catalyzed lacquer, which is a urethane modified lacquer. Post means the catalyst is added after it is manufactured and prior to finishing. Conversion varnish, or a 2-pack coating, is a finicky high solids coating that, like post cat, must have a catalyst added just before spraying. I think C.A.B. refers to Cellulose Acetate Butyrate. But don't hold me to that.

From contributor M:
Yes, the CAB lacquer is a single component coating, and it is water clear. It is sold in colors.

In regard to the two component conversion varnish, this name allows the finishers and others to know that this is not the standard varnish, but the newer two component type coating.

From the original questioner:
Could you possibly give me ICA product codes as examples of conversion, CAB and post-cat products? It would help me understand the terms more thoroughly.

From contributor S:
Conversion coatings are ones that undergo a chemical reaction, be it with oxygen from the air or with a catalyst or other added component. Non-conversion coatings are ones that don't change and can be re-dissolved by their own solvent (cellulose is an example).
Pre-cats are a combination between AC and NC varnishes. They dry first by solvent evaporation (NC), which concentrates the catalyst to a level where it then causes the catalytic reaction to occur. These have the catalyst added at manufacture, but never achieve the performance of the AC systems.

2K systems may be catalytic systems, usually based on amino resins, or use reactive additives, such as the 2K polyurethanes, epoxies and acrylics.

From the original questioner:
Thanks. So, as I expected, 2k and pre-cat are the same as in Europe, A/C is an example of a conversion coating and probably what is being referred to. Good to know. Any idea what post-cat would be in EU terms? (I may be wrong, but ICA has a cellulose modified bi-component PU which is not as hard as normal aromatic poly but has a long pot life; could this be it?)