I seem to have a drain pipe in my flat blocked by what seems to be a latex/rubber glove. I am unable to pull it out — is there a chemical that can reliably dissolve the glove and at the same time not damage the PVC pipe itself?
This is really a plumbing issue much more than a chemical dissolution issue. The problem is uncertain: "seems" to be a latex rubber glove; complete blockage.
I'm trying to envision how a rubber glove completely blocks a drain. Perhaps by partially blocking the drain, then catching hair and other particles - but on what? Perhaps on something else sticking into the drain - a root? Some other partial blockage?
Whatever; let's imagine pouring some solvent into the drain. For now, let's forget the PVC pipe: it is much thicker than the glove and will not dissolve before the glove does. As soon as the glove dissolves, the built-up head of solvent should flush away and prolonged rinsing with water will pretty much clean off the PVC pipe.
Unless the glove is caught on some projection and merely softens, while the 5 gallons of solvent drips away over a few minutes, leaving the glove softened and intermixed with the other captured trash. Now the problem has intensified. As solvent dissipates, the glove will become the adhesive that binds the trash together and to the PVC. But then the solution will be obvious: discover where the blockage is (with your snake), then remove that portion of the pipe and replace it. And don't do that ever again.
But if you insist on a chemical solution, I suggest air: pump up the pipe with a tire pump or one of those air blasters for toilet blockages and push the blockage down to larger pipe. It would also be helpful to load the blocked pipe up to your drain opening with a solution of dish detergent for lubrication and to decrease the volume that you have to pressurize.
If you must get more aggressive, there are tables of glove resistance (https://www.augusta.edu/services/ehs/chemsafe/PDF%20files/gloveselechart.pdf) online, but it would be easier to do your own experimenting. Since you have suspected it is a rubber glove, you might have other rubber gloves available that you could put into various solutions for a few hours or days to see how the glove behaves. But I think the glove is only part of the problem, and a good commercial drain cleaner would attack what I suspect is the helper-blocker, and dissolve that, and alkali isn't too gentle with latex rubber anyway (although the chart suggests natural rubber withstands alkali fairly well - except for ammonia). Also bleach is tough on natural rubber. Of course, YOU MUST NOT EVEN THINK OF MIXING AMMONIA WITH BLEACH!!!