Abstract: The object is to provide a writing instrument and a welding method of a writing point assembly as well as writing instrument parts connecting structure and connecting method, wherein the writing point assembly and an ink tube or/and a holder can be welded appropriately at a necessary area only without using ultrasonic waves, so as to be able to prevent dislodging of the writing point assembly, ink leakage and the like. The rear end part, of a metallic writing point assembly as a part of a writing instrument, which is inserted into a joint, is heated at the predetermined area (at least the fitted area in contact with the front end part of the joint), so as to weld the predetermined area of the writing point assembly to the surrounding part of the joint.

Abstract: There is disclosed a crystallizable poly(2,5-di-substituted-1,4-phenylene oxide), which exhibits an exothermic peak for crystallization of not less than 5 J/g at 150° C. or over when cooled after melting, and/or an endothermic peak, at the time of melting of crystals thereof, of not less than 5 J/g at 150° C. or over when re-heated after cooling of the melt, and which comprises a recurring unit of the following formula (I), and a method of preparing the same by polymerization of a 2,5-di-substituted-phenol of the following formula (II) by use of a copper complex catalyst made of a tridentate ligand of which nitrogen atoms coordinate to a copper atom in coexistence with oxygen: wherein R1's independently represent a hydrocarbon group or a substituted hydrocarbon group, and they may be the same or different. The crystallizable poly(2,5-di-substituted-1,4-phenylene oxide) is able to provide a melt molding which has a reduced degree of coloration and good heat resistance.

Abstract: For producing a pressurized ball-point pen refill in which ink is hard to leak, in which a ball is hard to drop out from a ball house, in which thin spot is hard to occur, in which an excellent initial writing performance is provided, and in which a writable distance is increased sufficiently, the ball-point pen refill 10 includes a tip 20, an ink storage tube 30 and a tail plug 40, wherein ink 80 is filled in the space of the ink storage tube 30 relatively near to the tip 20, and a pressuring gas 90 is filled in the space of the ink storage tube 30 relatively far from the tip 20. The tip 20 includes a ball 50 and a holder 60, and the ball 50 is formed to have a surface roughness (Ra) of 0.010 &mgr;m to 0.080 &mgr;m. The holder 60 has a ball house 61 and an ink guiding groove 62, and the ball house 61 has a side part 70 and a bottom part 71. Moreover, a formula 1.01≦&phgr;B/&phgr;A≦1.

Abstract: There is disclosed a crystallizable poly(2,5-di-substituted-1,4-phenylene oxide), which exhibits an exothermic peak for crystallization of not less than 5 J/g at 150° C. or over when cooled after melting, and/or an endothermic peak, at the time of melting of crystals thereof, of not less than 5 J/g at 150° C. or over when re-heated after cooling of the melt, and which comprises a recurring unit of the following formula (I), and a method of preparing the same by polymerization of a 2,5-di-substituted-phenol of the following formula (II) by use of a copper complex catalyst made of a tridentate ligand of which nitrogen atoms coordinate to a copper atom in coexistence with oxygen: wherein R1's independently represent a hydrocarbon group or a substituted hydrocarbon group, and they may be the same or different. The crystallizable poly(2,5-di-substituted-1,4-phenylene oxide) is able to provide a melt molding which has a reduced degree of coloration and good heat resistance.

Abstract: A catalyst obtained by contacting a specific transition metal compound (A) of Group 7 of the Periodic Table of the Elements, having a pyrazolyl group with an aluminum compound selected from organoaluminums and aluminoxanes and/or a specific boron compound, and a process for producing an addition polymer which comprises polymerizing an addition polymerizable monomer with the catalyst.

Abstract: There is disclosed a crystallizable poly(2,5-di-substituted-1,4-phenylene oxide), which exhibits an exothermic peak for crystallization of not less than 5 J/g at 150° C. or over when cooled after melting, and/or an endothermic peak, at the time of melting of crystals thereof, of not less than 5 J/g at 150° C.

Abstract: An ink replenishing apparatus replenishes an ink cartridge, which has an ink absorber made of a porous body or fiber bundle in an ink storage chamber that stores ink, with ink supplied from a replenishing ink cartridge through a relay core. An ink holding force d of capillary tubes of the relay core and an ink holding force D of capillary tubes of the porous body or fiber bundle satisfy the following relation d<D.