ADHESIVE DETECTION METHODS

摘要

Adhesive compositions useful for bonding fluorescent material-containing cellulosic substrates such as envelopes may be formulated using an adhesive polymer such as an emulsion of polyvinyl acetate in water and one or more compounds capable of reducing the degree of fluorescence exhibited by the substrate in areas of the substrate surface having the adhesive coated thereon. When irradiated by short wavelength light, the surface areas containing the adhesive coating appear darker than the surface areas that are free of adhesive, allowing quality control problems associated with application of the adhesive to be readily monitored and corrected. At the same time, however, the adhesive may be formulated such that the fluorescence-reducing compound does not alter the appearance of the adhesive coating when viewed under normal daylight conditions.