Ink eraser holds chemical in microcapsules embedded in PVC block - particles rubbed of PVC absorb excess bleach

摘要

An eraser which neither abrades the paper surface nor leaves excess bleach behind to spoil the written correction is a block of softened polyvinyl chloride contg. 5% by volume of microcapsules of chemical bleach. These rupture under friction with the paper and release the bleach to destroy the writing. It becomes possible to use a much smaller excess of bleach than before, and what little surplus there is, is absorbed by the particles which rub off the PVC block and are brushed away. The paper surface is left able to accept ink normally.