I have a german ww2 era armband, the white patch floureses under the blacklight that means its rayon or another simular material. a rule of thumb for US patchs is we didnt use rayon or nylon until after 1950's and the patchs should not glow. My question is, is this true for 1940's war years patchs, was rayon used for the military then. This is a common problem sorting out the repops, Thanks in advance for any that can help