| 摘要 |
The nib portion of a ball-point reservoir pen is made by injection moulding with a material comprising a thermoplastic substance loaded with at least 20% by volume with a finely dispersed solid filler which has an elasticity modulus in compression of not less than 2X106 lbs. per square inch, and has a melting point above the moulding temperature of the thermoplastic material, the elasticity modulus in compression of the resultant moulded material being not less 6X105 lbs. per square inch and preferably more than 8X105 lbs. per square inch. The thermoplastic substance has a compression modulus of not less than 1X105. Examples of thermoplastics are synthetic polyamide resins, such as nylon or polyhexamethylene-sebacamide, and polycarbonate or acetal resins, such as polycarbonic acid ester of 4,4-dihydroxydiphenyl-2, 2 propane. The filler may comprise minute beads of copper, aluminium, glass, or mica, and where copper is used, the beads may be silver plated. Small quantities of pigments and graphite or molybdenum disulphide may be added. In one example, a powdered matrix of polyhexamethylene-sebacamide having a compression modulus of 3X105 lbs. per square inch when completely dry, is mixed with 45% of a filler of electrolytic grade pure copper powder in bead form and particle size 0.0001 inch to 0.0015 inch, such that the injection moulded material has a compression modulus of 11X105 lbs. per square inch. In other examples, the filler consists of 51% of glass powder in bead form, or 11% of mica powder in flake form.
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