Abstract: A water-based ballpoint pen using a cemented carbide ball comprising tungsten carbide and a metal binder as a writing front end, wherein cobalt and/or nickel are contained in the cemented carbide ball as the metal binder in an amount of 1 to 20% by weight based on the total amount of the ball and which further includes an aqueous ink composition containing a colorant, water, a phosphate ester-based surfactant, and any one or more compounds of a thiadiazole represented by formula (1), 5-mercapto-3-phenyl-1,3,4-thiadiazole-2-thione or a salt thereof, and an oligomer of 2,5-dimercapto-1,3,4-thiadiazole: wherein X and Y each represents any substituent of CH3, NH2, and SM, and M represents any of hydrogen, an alkali metal, an ammonium, and an alkanolamine.

Abstract: A water-based ink composition for a ballpoint pen wherein the initial start of writing and writing over time is good, and no blur in handwriting occur and a stable writing performance can be sustained and good handwriting can be continuously formed. A water-based ink composition for a ballpoint pen dissolving or dispersing a coloring agent in an aqueous medium. The aqueous medium substantially contains no water-soluble organic solvent and is composed of water. The water-based ink composition includes a thickening inhibitor together with a shear thinning viscosity-imparting agent. As the thickening inhibitor, one or two or more are selected from a group of polyalkylene glycol, polypropylene glycol derivatives, polyvinyl alcohol, polyvinyl pyrrolidone, cellulose-based polymer compounds, polymer compounds having a polyalkylene oxide group and/or surfactants having a polyoxyethylene group.

Abstract: To provide a water-based ballpoint pen with a good feel while writing, which hardly causes the proceeding of ball corrosion with time and can maintain an excellent lubrication performance at writing. A water-based ballpoint pen using a cemented carbide ball comprising tungsten carbide and a metal binder as a writing front end, wherein cobalt and/or nickel are contained in the cemented carbide ball as the metal binder in an amount of 1 to 20% by weight based on the total amount of the ball and which further includes an aqueous ink composition containing a colorant, water, a phosphate ester-based surfactant, and any one or more compounds of a thiadiazole represented by formula (1), 5-mercapto-3-phenyl-1,3,4-thiadiazole-2-thione or a salt thereof, and an oligomer of 2,5-dimercapto-1,3,4-thiadiazole: wherein X and Y each represents any substituent of CH3, NH2, and SM, and M represents any of hydrogen, an alkali metal, an ammonium, and an alkanolamine.

Abstract: A water-based ink composition for a ballpoint pen wherein the initial start of writing and writing over time is good, and no blur in handwriting occur and a stable writing performance can be sustained and good handwriting can be continuously formed. A water-based ink composition for a ballpoint pen dissolving or dispersing a coloring agent in an aqueous medium. The aqueous medium substantially contains no water-soluble organic solvent and is composed of water. The water-based ink composition includes a thickening inhibitor together with a shear thinning viscosity-imparting agent. As the thickening inhibitor, one or two or more are selected from a group of polyalkylene glycol, polypropylene glycol derivatives, polyvinyl alcohol, polyvinyl pyrrolidone, cellulose-based polymer compounds, polymer compounds having a polyalkylene oxide group and/or surfactants having a polyoxyethylene group.

Abstract: A water-based ink composition for ballpoint pen, which comprises at least a colorant, water, a shear-thinning tackifier and a thickening inhibitor, wherein a ratio (x) of a viscosity after evaporation of 40 wt % of water from the total ink amount to an initial ink viscosity (as measured by EMD viscometer at 1 rpm and 20° C.) is 2 or less; and a ballpoint pen comprising the same.

Abstract: A water-based ink composition for ballpoint pen, which comprises at least a colorant, water, a shear-thinning tackifier and a thickening inhibitor, wherein a ratio (x) of a viscosity after evaporation of 40 wt % of water from the total ink amount to an initial ink viscosity (as measured by EMD viscometer at 1 rpm and 20° C.) is 2 or less; and a ballpoint pen comprising the same.

Abstract: There are described freeze-dried food products which have porous structure with fine texture than those obtained by conventional processes to give smooth melting in mouth and a process for preparing the freeze-dried food products. According to the process, raw materials for the food are made into a form of aqueous solution or paste, emulsified, made into semi-frozen state by cooling the emulsion, freeze-dried by further cooling in a mold, and then subjected to freeze-drying treatment.