one for the chemists..

I think you need a two-pronged approach for removing sealant. I find a multi-tool with a flat, toothless blade really rips through the job clearing the bulk of the stuff in no time before finishing off with chemical solutions (which take an age).

R is the term for the basic hydrocarbon carrier. The bit on the end is the active ingredient under discussion. I don't know what p means. Poly?

I think the numbers tell you where the diene part comes on the chain. I was thinking it sounded nitrogenous but it turns out to mean double bonded.

As it stands it's not a valid name for a chemical.

As already noted R is often used as a sort of wildcard to indicate one of a range of different but similar structures. The description of what that range might be will be somewhere else.

p, an abbreviation for para implies a six carbon benzene ring with the hydrogen atoms on carbons 1 and 3 being replaced with something else. The full chemical formula should specify what those substitutions are.

Powder paint is probably made from a two-pack epoxy which should resist most solvents. It will not resist chemicals that can chemically break down the polymer.

Many of these products contain delimonene, would that make sense?

That's D-Limonene where the D is an abbreviation for Dextro. Limonene exists in two forms that are mirror-images of each other. The other form would be L-Limonene, L meaning Laevo or left. D-Limonene is one of the major components of orange oil. It's probably there as a perfume although looking at the structure it's probably a reasonably good solvent.

When I first read your post I could see nothing to disagree with, but then I Googled for (R)-p-1,8-diene (note , substituted for '), and it turned up many references to (R)-p-mentha-1,8-diene and also R-(+)-Limonene. TMH mentioned delimonene, so the latter caught my eye.

This Sigma-Aldrich data sheet on (R)-(+)-Limonene

Alternative names are (+)-p-Mentha-1,8-diene, and (R)-4-Isopropenyl-1-methyl-1-cyclohexene, and from the structure it's a substituted cyclohexane. Further down the page is a reference to (S)-(-)-Limonene, and from that one's structure it would appear that the (R)-(+) and (S)-(-) just refer to different isomers of the stuff, rather than R being a hydrocarbon chain radicle.

The PDF file at

So to answer the TL's question, (R)-p-1,8-diene is closely related to d-Limonene, which also answers TMH's query. Limonene is a cyclic terpene with a strong smell of oranges, apparently, according to Wikipedia

So it won't harm you, but it may well attack your paint. Proceed with caution.

It's in a lot of "label removers". It's impressive how quickly these attack label glue yet don't seem to touch any common plastics.

In message , Chris Hogg writes

Sorry. The ' was my miss key! I had no idea how important a comma could be:-)

I've snipped your piece for brevity but it served to convince me I was right to stick to electricity having dropped chemistry at O level.

It does soften/strip silicone but takes time.

Test strip still OK but sharp edged tools do nearly as well. Thanks

I'm sure the 'label removers' are better, but I've always found that hot water then white spirit is much cheaper for that task.

Label removers are significantly better than any other solvent I've come across, no scraping or scrubbing just lift the edge and labels fall off leaving zero residue. I occasionally get used honey jars back from friends and relatives that have been through a dishwasher. The jars are clean but the hot water has a habit of hardening the glue and making removal significantly more difficult.