Silk, as a natural product has a unique odor, which comes from the residual sericin, a.k.a silk glue. The smell of sericin can often be mistaken for something more serious such as the smell of some industrial chemical agent, but you can rest assured that it is nothing of the sort. In fact, we recommend that you test your silk if there is no smell when you open the package because there are manufacturers that remove the smell by bleaching the silk, which is great until you realize your silk is becoming brittle and deformed soon after use.
In our experience, the odor is most noticeable when the comforters are unpacked for the first time, and gradually dissipates over the next few hours, and extreme cases, days. Eventually the smell will disappear almost completely as the sericin in the silk floss is in trace amounts and only produces so much odor during a given amount of time.