Abstract: The present invention provides a water-based ink composition for a ballpoint pen that is less likely to cause bleeding of a written trace in writing, provides a favorable written trace without causing no blurring or line splitting, and excels in the storage stability of the ink composition; and a water-based ballpoint pen using the ink composition. A water-based ink composition for a ballpoint pen comprising water, a coloring agent, a copolymer having a specific structure; and a water-based ballpoint pen using the ink composition.

Abstract: The present invention provides a water-based ink composition for a ballpoint pen that is less likely to cause bleeding of a written trace in writing, provides a favorable written trace without causing no blurring or line splitting, and excels in the storage stability of the ink composition; and a water-based ballpoint pen using the ink composition. A water-based ink composition for a ballpoint pen comprising water, a coloring agent, a copolymer having a specific structure; and a water-based ballpoint pen using the ink composition.

Abstract: In order to improve the endurance of this internal solution for a reference electrode beyond that in the prior art, the solution is made to contain a copolymerized material of a crosslinker having a plurality of non-acrylamide functional groups, and a non-acrylamide monofunctional hydrophilic monomer.

Abstract: The invention aims at providing a solid writing material that does not adversely affect the color changing property of script and can obtain sufficient strength. This aim is achieved by the solid writing material that includes: a reversible thermochromic microcapsuled pigment encapsulating a temperature-sensitive color-changeable color-memorizing composition; an excipient; and a resin; the temperature-sensitive color-changeable color-memorizing composition including at least (a) an electron-donating coloring organic compound, (b) an electron accepting compound and (c) a reaction medium effecting reversibly an electron transfer reaction between the (a) and (b) components in a specific temperature range; wherein the excipient or the resin includes a styrene-structure-containing polymer.

Abstract: In order to improve the endurance of this internal solution for a reference electrode beyond that in the prior art, the solution is made to contain a copolymerized material of a crosslinker having a plurality of non-acrylamide functional groups, and a non-acrylamide monofunctional hydrophilic monomer.

Abstract: The invention aims at providing a solid writing material that does not adversely affect the color changing property of script and can obtain sufficient strength. This aim is achieved by the solid writing material that includes: a reversible thermochromic microcapsuled pigment encapsulating a temperature-sensitive color-changeable color-memorizing composition; an excipient; and a resin; the temperature-sensitive color-changeable color-memorizing composition including at least (a) an electron-donating coloring organic compound, (b) an electron accepting compound and (c) a reaction medium effecting reversibly an electron transfer reaction between the (a) and (b) components in a specific temperature range; wherein the excipient or the resin includes a styrene-structure-containing polymer.

Abstract: The invention aims at providing a solid writing material having a good color changing property or color extinguishing property, and having an excellent light resistance, moldability and strength. The solid writing material includes an inner core usable for writing and an outer shell covering an outer peripheral surface of the inner core; the inner core including a reversible thermochromic microcapsuled pigment encapsulating a temperature-sensitive color-changeable color-memorizing composition and an excipient; the temperature-sensitive color-changeable color-memorizing composition including at least (a) an electron-donating coloring organic compound, (b) an electron accepting compound and (c) a reaction medium effecting reversibly an electron transfer reaction between the (a) and (b) components in a specific temperature range; the outer shell including a filler.

Abstract: [Object] To provide a reversibly thermochromic composition free from accidental discoloration by heat conducting from the opposite side writing surface or by self-heating due to quick writing; and also to provide a solid writing material and a writing ink composition comprising that composition. [Means to solve the problem] A reversibly thermochromic composition comprising a combination of: (a) a reversibly thermochromic component capable of being discolored or decolored by heat and (b) a component for controlling heat conducting to the reversibly thermochromic component; and also a solid writing material and a writing ink composition comprising that composition.

Abstract: A magnetic display panel that excels in display and erasure performance, being free from any change of writing and display performance even upon repetition of display and erasure and that facilitates inhibition of thixotropic property and specific gravity control for dispersion medium vs. magnetic display substance, etc., ensuring low toxicity and low pollution. In particular, a magnetic substance display panel comprising a dispersion with yield value composed mainly of a magnetic display substance, water and an aqueous thickener and a support holding the dispersion, characterized in that the aqueous thickener is at least one member selected from among a crosslinked acrylic acid copolymer, a crosslinked maleic anhydride copolymer, a thickening polysaccharide and a polyvinylalkylamide.

Abstract: A magnetic display panel that excels in display and erasure performance, being free from any change of writing and display performance even upon repetition of display and erasure and that facilitates inhibition of thixotropic property and specific gravity control for dispersion medium vs. magnetic display substance, etc., ensuring low toxicity and low pollution. In particular, a magnetic substance display panel comprising a dispersion with yield value composed mainly of a magnetic display substance, water and an aqueous thickener and a support holding the dispersion, characterized in that the aqueous thickener is at least one member selected from among a crosslinked acrylic acid copolymer, a crosslinked maleic anhydride copolymer, a thickening polysaccharide and a polyvinylalkylamide.