The only glue I ever found to work on such material is Altufix. Overly expensive, 2-component glue that is originally designed for PMMA, hence its name. It works by "welding" the two parts together, unlike conventional or epoxide or cyanoacrylate glues. I fear either a new hinge or a bottle of Altufix come close to the price of a complete SL-D2. In fact I've never seen a spare SL-D2 hinge for sale, but who knows, you might be lucky. I'd try ebay and the other usual suspects.