Document repair tapes differ from common clear plastic in several ways. The carrier (the part of the tape that holds the adhesive) is thin, acid-free paper, not plastic. It is not as stiff as plastic tape so a page can turn and bend more easily. The adhesive used is a neutral acrylic adhesive that should not dry up, yellow over time or seep out the edges of the document repair tape. Because this adhesive is neutral (neither’ acidic nor alkaline), it should not react chemically with the paper.
The manufacturers of these tapes have tested the materials using artificial aging tests and they believe these tapes will remain stable over time and can be removed easily. Actual experience is not always so positive. Some libraries are finding that these tapes dry hard and crack or that the adhesive dries up and the paper carrier falls off leaving the paper discolored.
Because of these problems, document repair tapes should not be used on valuable books. Document repair tape has become accepted for use as a quick way to repair paper tears and is definitely better than clear plastic tape.