"use" claims

[pentazole]

Patenting a use seems fairly common in Europe, or at least in Germany.  One cannot patent a use in the United States, unless that use is properly claimed through a process claim.  For example, compound X is widely known as a flavor enhancer for meat.  Dr. Carnivore discovers that if you dissolve compound X in vinegar, the vinegar turns to gold.

One cannot obtain a patent claiming:

The use of compound X to make gold;

however, one can obtain a patent claiming:

A process for making gold, comprising mixing compound X with vinegar;

of course assuming it's not obvious or anticipated by the prior art.

However, in Germany, it seems that the "use" claim is patentable.  For example, if there's a patent out there that discloses adding compound X to vinegar for some reason, but nothing about gold is disclosed, you can still get a patent on a claim reciting "The use of compound X to make gold".

My question is, are these "use" claims enforceable?  Like if Dr. Carnivore has an issued patent in Germany for the use of compound X to make gold, and Mr. Greedy mixes compound X with vinegar but when sued by Dr. Carnivore asserts that he's mixing the two in order to experiment with a new steak marinade, can he still be sued?

Are these "use" claims some form of a trademark perhaps, or something like that, moreso than a patent?

[bartmans]

Although this post is already quite old, I though to throw in a reply.

First of all: yes, a use claim is enforceable.
However, as you pointed out, it only covers the specific use, and if the compound or process is used for another purpose, it does not infringe.

Classical examples are the so-called first and second medical use claims. Assume that compound X already exists as a colouring dye for textiles. Now you have found that it can be used against headache. You could obtain a patent in Europe with the following claim:
- compound X for use as a medicament.
This would cover all medical use of the compound and somebody selling compound X as colouring dye still may continue to do so.
More extreme, even a second or following medical use may be patented, e.g. when you find out that compound X is also useful in treating heart disease, you could obtain a patent with a claim:
- compound X for use in the treatment of heart disease.

Note that the claims to medical use, are not 'use'-claims, but compound claims. This is an exception, which has been entered into the European Patent law, since use claims for therapeutics are excluded from patentability.

Of course it is easy to spot infringement of these uses in the medical field: medicines should be registered while naming the indication for which the medicine is meant, and that would provide you the information for your infringement suit.

It becomes more difficult outside the medical field: the second non-medical use. This is patentable, as was illustrated in the famous Mobil Oil case, where a claim for the use of a composition as anti-rust agent was found allowable although there was prior art that showed the lubricant effects of the same composition (and even in the same place of application: a motor).
Now, infringement can only be proven if this new use is indicated on the product or in advertisements to the product. Therefore, such claims have also been mentioned 'packaging-claims', since infringement is not caused by the mere sale of the product, but by the advertisement on the packaging: "This oil can be used as anti-rust".