爱美之心,人皆有之。随着医学科学事业的发展和经济收入的增加,不少中老年人也开始注意修饰打扮起来了。当他们头上的“银丝”逐渐增多的时候,便使用染发剂以挽回失去的青春。但是,目前,市场上出售的染发剂品种繁多,就其作用时间来讲,不外乎短暂性、半永久性和永久性三类。永久性的染发剂是用小分子芳胺染料制成,同时加6% Heart of beauty in everyone. With the development of medical science and the increase of economic income, many middle-aged and elderly people have begun to pay attention to grooming. When the “silver” on their heads is growing, they use hair dyes to regain their lost youth. However, at present, the variety of hair dyes sold on the market is nothing more than transient, semi-permanent and permanent in terms of their duration of action. Permanent hair dye is made of small aromatic amine dye, plus 6%