An erasable ink composition for use in writing with a marking pen which comprises an organic solvent, optionally a resin soluble in the solvent, a pigment dispersed in the solvent and additives, the improvement in the additives comprising:
(a) a fatty acid monoester of an aliphatic alcohol wherein the fatty acid has not less than six carbons in amounts of about 0,5-20 % by weight;
(b) a fatty acid triglyceride in amounts of about 0,5-20 % by weight;
(c) a higher aliphatic hydrocarbon which is liquid at normal temperatures in amounts of about 0,2-5 % by weight; and
(d) a polyoxyethylene alkyl ether phosphoric acid ester in amounts of about 0,5-7 % by weight; each based on the ink composition.
The writings with the ink composition is erasable even after a long standing.
A water base erasable ink composition which comprises:
(a) water as a solvent in amounts of 50-97.9 % by weight;
(b) a coloring agent dispersed or dissolved in water in amounts of 1-20 % by weight;
(c) an aqueous emulsion of at least one nonvolatile or only slightly volatile compound which is liquid at room temperatures and is selected from the group consisting of aliphatic carboxylic acid esters, higher hydrocarbons and higher alcohols in dry amounts of 1-15 % by weight; and
(d) a water soluble resin or a water-solubilized resin which is film forming at room temperatures in amounts of 0.1-15 % by weight.
The water soluble resin or water-solubilized resin may be displaced by an aqueous emulsion or a hydrosol of water insoluble resins.
Surface-modified wholly aromatic polyamide filaments usable as a reinforcing material for rubber or synthetic resin articles, each comprising a wholly aromatic polyamide core filament; an intermediate coating layer formed on the core filament and comprising a copolymer of (a) a water-soluble or self-emulsifying urethane-modified bisphenol A type epoxy compound with an epoxy equivalent of 200 to 800 with (b) an aliphatic polyglycidylether compound with an epoxy equivalent of 100 to 250; and a surface coating layer formed on the intermediate coating layer and comprising a lubricant, the weight ratio of the intermediate coating layer to the surface coating layer being 20 : 80 to 80 : 20.
A writing board ink composition containing a medium of, or based on, a lower alcohol solvent, wherein a diketopyrrolopyrrole pigment represented by the following formula [I] having a median Stokes diameter of not more than 0.2 µm, an alcohol-soluble polymer, a scraping agent and a surfactant are contained in the medium.
wherein R¹ and R² independently represent an unsubstituted or non-water-solubilizing substituent substituted phenyl group or naphthyl group; R³ and R⁴ independently represent hydrogen or a non-water-solubilizing substituent.
The writing board ink composition of the present invention remains stable for a long time while in pens even when the resin content is such that unclear writing and scrapability reduction can be avoided, since the pigment of ultrafine particle size is fast to lower alcohol solvents.