No, loaning a book is not breaking copyright, as long as there is no copying of the content, though loaning a pattern might be. The rule of thumb is, one person can read a book at a time, so if you loan the book, the person you loaned it to is reading it.
But I gotta tell ya'll ... I think the whole copyright thing in the creative world has gotten out of hand. From designers saying you can't use their fabric to make an item to sell, to pattern makers who state you can't use their pattern to make an item to sell ... it's all ridiculous, and more importantly, not enforceable. Did you know that according to some designers, we break the rules every single day, right here on Quilting Board? Every time someone posts a photo of a quilt they've made from a pattern, some designers think you're infringing on their copyright.
Quilts are utilitarian items, and outside of a patented technique, I don't think copyrights, even when registered, are going to be enforceable, because unless it's a truly unique design (and truthfully, how many truly unique designs are there these days that wouldn't be considered public domain?), it's not subject to copyright protection.