| 摘要 |
Eraser compsn. comprises PVC or a PVC copolymer, a plasticiser and a non-volatile Indian ink solvent or swelling agent to abrade the Indian ink. The solvent comprises (a) a carboxylic acid esterified with a polyvalent alcohol or its ether. The alcohol or its ether contains >=2 OH gps. and the carboxylic acid contains >=1 COOH gp. and its ester contains >=1 OH gp.; or (b) an ether where one organic gp. is derived from a polyvalent alcohol or its ehter and the other organic gp. is derived from ethylene oxide, the alcohol or its ether contg. >=2 OH gps. and the ether contg. >=1 OH gp. The solvent attacks the Indian ink rapidly, does not smudge, leaves no colour, does not discolour the eraser and is compatible with the PVC and the plasticiser. |
