I have found a discription how to make a safe cat collar. Following the discription it will break by pull of approx. 1kg and should last between 4 and 6 weeks. The collar is simple a stripe of very stable paper called "Chromolux". Like all paper the information could be written on it. In the discription of Chromolux I read the paper is painted on one side with lacquer. I assume this cause a water resistance. Combined with a snap or simple sticky tape it could be formed to a collar. The collar could be made more visible with reflecting stickers or more personal with rhinestones or whatever one imagines. Now I am waiting for my order and will report the test here later.