Abstract: A process for manufacturing microcapsules by dissolving or dispersing microcapsule contents in an aqueous solution of acrylic acid-methacrylic acid copolymer and/or acrylic acid-itaconic acid copolymer, then polymerizing urea and/or melamine and formaldehyde in the solution or dispersion adjusted to pH 2.5.about.6.0, and forming film of urea-formaldehyde copolymer, melamine-formaldehyde copolymer, or urea-melamine-formaldehyde copolymer around capusle contents.Microcapsules manufactured by this process are useful for colors for carbonless paper or thermo-changeable colors.

Abstract: A writing set comprising a combination of paper printed thereon with two or more coloring bands using two or more types of leuco dye which develop different colors and a writing means which contains a solution of acid materials which develops the color of the leuco dyes.When characters, pictures, etc. are written on the paper, the colorless leuco dyes in the written portion develop color to form colorful characters, pictures, etc.

Abstract: An ink composition for writing on an absorbent or pervious writing surface to form thereon a writing or marking composed of an inner portion of a metallic color with outer contour portions therearound of a dyestuff-based color, which composition comprises:a nonleafing metal powder pigment as a first pigment,an inorganic or organic pigment as a second pigment,a dyestuff, anda solvent,the nonleafing metal powder pigment being dispersed in the solvent and having a particle size sufficiently large so as to substantially not permeate or be absorbed into the writing surface, andthe second pigment being dispersed in the solvent and either having a particle size sufficiently large so as to substantially not permeate or be absorbed into the writing surface, or having a particle size sufficiently large so as to substantially be adsorbed on the nonleafing metal powder pigment,the dyestuff being dissolved in the solvent, being capable of substantially permeating or being absorbed into the writing surface and diffusing in

Abstract: An ink composition for writing or marking on an absorbent or pervious writing surface to provide a writing or marking composed of an inner portion of a first color with outer contour portions therearound of a second color, which composition comprises:a first colorant,a second colorant anda vehicle,said first colorant being dispersed in said vehicle and having a particle size sufficiently large so as to substantially not permeate or be absorbed into said writing surface andsaid second colorant being dispersed or dissolved in said vehicle, being capable of substantially permeating or being absorbed into said writing surface and diffusing into the area on said surface proximate to said writing,whereby said second colorant forms said outer contour portions around said inner portion of said first colorant.

Abstract: 1. An erasable ink composition for writing on an impervious writing surface to form thereon a writing or marking which is erasable by wiping the surface; the composition comprising:about 40-90% by weight of a volatile organic solvent;about 1-20% by weight of a colorant;about 0.5-30% by weight of a resin which is soluble in the organic solvent; andabout 1-25% by weight of a fatty acid ester of trimethylolalkane of the general formula ##STR1## wherein R.sup.1 represents an alkyl of 1-3 carbons, R.sup.2 and R.sup.3 represent independently hydrogen or an alkyl of 1-21 carbons, and R.sup.4 represents an alkyl of 3-21 carbons.

Abstract: An ink composition for a marking pen is disclosed which permits smooth writing even after a long period of standing of the pen with no cap. The ink composition comprises an organic solvent, a pigment, a resin and at least one additive selected from the group consisting of a glyceride of specified structure, and an alkylamide alcohol of specified structure and a sorbitan fatty acid ester.An erasable ink composition for writing on a writing surface such as one of resin is also disclosed, which further includes, in addition to the above, a separating agent which is a non-volatile or only slightly volatile liquid or semi-solid at normal temperatures and has a lower vapor pressure than the solvent, and is soluble in the solvent.

Abstract: An ink composition for writing on an absorbent or pervious writing surface to form thereon a writing or marking composed of an inner portion of a first color with outer contour portions therearound of a second color, which composition comprises:a polar organic solvent,a nonpolar organic solvent which is miscible with the polar organic solvent,a first dyestuff which is soluble both in the polar organic solvent and a mixture of the polar organic solvent and the nonpolar organic solvent, but which is insoluble in the nonpolar organic solvent, anda second dyestuff which is soluble both in the nonpolar organic solvent and a mixture of the polar organic solvent and the nonpolar organic solvent, the second dyestuff being different in color from the first dye-stuff,whereby the first dyestuff forms in conjunction with the second dyestuff the inner portion of the first color based on the first and the second dyestuffs, and the second dyestuff forms the outer contour portions of the second color based on the second dyes

Abstract: A method for writing or marking on an absorbent or pervious writing surface to provide a writing or marking composed of an inner portion of a first color with outer contour portions therearound of a second color, which method comprises applying to said surface a writing or marking with an ink comprising:a first colorant,a second colorant anda vehicle,said first colorant being dispersed in said vehicle and having a particle size sufficiently large so as to substantially not permeate or be absorbed into said writing surface andsaid second colorant being dispersed or dissolved in said vehicle, being capable of substantially permeating or being absorbed into said writing surface and diffusing into the area on said surface proximate to said writing,whereby said second colorant forms said outer contour portions around said inner portion of said first colorant.

Abstract: A water base pigment ink composition for writing comprises a pigment, a dispersing agent, an anti-drying agent and an aqueous medium, in which said dispersing agent is a water soluble amine salt or ammonium salt of a copolymer comprises at least 50 molar % of a hydrophobic addition-polymerizable monomer and less than 50 molar % of acrylic acid or methacrylic acid, and said anti-drying agent is urea, thiourea or a derivative thereof.

Abstract: An erasable ink composition for writing or marking on an impervious surface which comprises: about 40-90% by weight of an organic solvent; about 1-10% by weight of a pigment; about 1-25% by weight of a separating agent which is soluble in the solvent, and is a non-volatile or only slightly volatile liquid at normal temperatures having a lower vapor pressure than the solvent; about 0.5-20% by weight of a synthetic resin which is soluble both in the solvent and a solution of the separating agent in the solvent, and is insoluble or only slightly soluble in the separating agent; and about 0.05-20% by weight of a hydrocarbon wax.

Abstract: A method for manufacturing pencil leads which comprises thoroughly mixing 100 parts by weight of graphite, 30 to 60 parts by weight of a water-soluble nigrosine, an emulsion containing 10 to 30 parts by weight of wax, and water together, extruding the resultant base mixture from a die into rods of a desired diameter, drying the rods to remove the water contained therein, and then baking the rods at elevated temperatures. The base mixture may contain 10 to 30 parts by weight of a water-soluble organic nonelectrolyte of high molecular weight such as cellulose ethers and/or not more than 10 parts by weight of carbon black in relation to 100 parts by weight of graphite so as to further improve the quality of the leads obtained.