| 摘要 |
PURPOSE:To obtain a writing implement which is excellent in writing performance at a low cost by a method wherein a pen pointsealing up member which seales up a pen point after fitting a cap is composed of polymeric resilient material which is ink resistant and prevents the pen point part from drying, and carbon dioxidetransmission coefficient of the material is made a specific value or under. CONSTITUTION:A material which is more excellent in ink resistance in polymeric resilient materials and at most 30X10<-17>m<4>(N, S) at 25 deg.C in carbon dioxide transmission coefficient, is used for a pen point-sealing up member 3. Then, by aiming at permeability of a pen point-sealing up member 3 from a test result, NBR containing 20% of acrylonitrile, butyl rubber (11K), and a fluororubber of which carbon dioxide (CO2) transmission coefficient is smaller than that of ethylene-propylene rubber in preliminary experiment are formed with a former. A writing performance test is carried out under the same conditions. Excellent results are obtained with butyl rubber and the fluororubber. |
