The issue of the present invention is to provide a disazo pigment in which the polychlorinated biphenyl (PCB) content in addition to the primary aromatic amine (PAA) content is reduced. The present invention provides a pigment composition containing a disazo pigment, an alkylamine that has an alkyl group having a carbon number of 8 or more, and a poly(oxyethylene) alkyl ester that has an alkyl group having a carbon number of 8 or more. Preferably, the disazo pigment includes at least one disazo pigment selected from a group consisting of C.I. Pigment Yellow 83, C.I. Pigment Yellow 13, and C.I. Pigment Yellow 14.

An electrolytic dye reduction method comprises preparing a catholyte by dispersing a dye in a leucodye comprising electrolyte. In a preferred method the leucodye like leucoindigo is the sole dispersing aid.

The present invention provides an aqueous pigment dispersion liquid being such that a pigment is finely dispersed, and the viscosity, and the particle diameters of the pigment are unlikely to fluctuate, being excellent in storage stability, and enabling preparation of an emulsion-polymerized toner having properly controlled particle diameters while improving the pigment utilization rate. The aqueous pigment dispersion liquid is an aqueous pigment dispersion liquid for an emulsion-polymerized toner containing a pigment, a dispersant, and an aqueous medium. The dispersant is a polymer containing a constitutional unit (A) derived from a monomer (A) such that a group containing a (meth)acryloyloxy group or the like is bonded to one end of a particular polyethylene glycol chain or the like, and a constitutional unit (B) derived from a monomer (B) having a carboxy group or the like, the polymer has a number average molecular weight in terms of polystyrene of 4,000 to 15,000, as measured by gel permeation chromatography, the polymer is contained in a state of being not ionized substantially, and the aqueous pigment dispersion liquid has a pH of 3.0 to 8.4.

The purpose of the present invention is to provide a pigment composition having outstanding dispersion characteristics, weather resistance, and heat resistance, has favorable storage stability, minimizes fading over time in a basic atmosphere, and contains isoindoline compounds.

The pigment composition contains the isoindoline compound represented by formula (1) below and the isoindoline compound represented by formula (2) below.

##STR00001## [in the formula, R.sub.1 to R.sub.4 represent hydrogen atoms, R.sub.5 and R.sub.6 each independently represent alkyl groups, and A and A′ represent a group represented by formula (3) below, formula (4) below, or formula (5) below,

##STR00002## In the formula, X represents —O— or —NH—, R.sub.7 represents an alkyl group or an aryl group, and R.sub.8 to R.sub.14 each independently represent hydrogen atoms, halogen atoms, alkyl groups, alkoxy groups, aryl groups, aryloxy groups, thioalkyl groups, or thioaryl groups.]

[Problems] To provide a reversibly thermochromic composition having excellent contrast between a colored state and a decolored state, and excellent light resistance, and a reversibly thermochromic microcapsule pigment encapsulating the reversibly thermochromic composition.

[Solution] Disclosed is a reversibly thermochromic composition including: (a) an electron-donating color-developing organic compound; (b) a combination of a compound having a specific structure as an electron-accepting compound; and (c) a reaction medium which reversibly induces an electron transfer reaction between the component (a) and the component (b) in a specific temperature range, and a reversibly thermochromic microcapsule pigment encapsulating the reversibly thermochromic composition.

This invention relates to a process for the preparation of a dispersion comprising coloured or black particles, such coloured or black particles prepared by the process, the use of the dispersion and the coloured or black particles in electrophoretic fluids, and electrophoretic display devices comprising such fluids.

Nanoparticles and compositions thereof are provided for detecting and/or preventing food spoilage. Methods of making the nanoparticles and compositions, and methods of using the nanoparticles and compositions, e.g. in food packaging, are also provided. The nanoparticles can have a hydrophobic core containing a hydrophobic active agent, e.g. a hydrophobic dye and/or an antimicrobial agent, for detecting and/or preventing food spoilage. The nanoparticles can also have a copolymer of a hydrophobic polymer repeat unit, e.g. styrene or lactic acid, and a pH responsive dendrimer repeat unit. The pH responsive dendrimer repeat unit can have a pH responsive amine core having a plurality of branched acrylate arms extending therefrom. The nanoparticles can be chemically stable at neutral pH, and then release the hydrophobic active agent at a pH range indicative of food spoilage. By releasing the hydrophobic dye and/or antimicrobial agent, the nanoparticles can detect and/or inhibit food spoilage.

Aqueous pigment preparations contain at least one organic and/or inorganic pigment and/or filler, at least one dispersant of formula (I) or (II), or mixtures of dispersants of formulae (I) and (II), wherein n is an integer ≥1, z is an integer ≥1, R1 is an aliphatic, linear or branched hydrocarbon radical with 1 to 30 carbon atoms or a hydrogen atom or the structural unit —O—X or the structural unit CH.sub.2—O—X, and the structural unit X of formula (III), wherein a is an integer from 1 to 50, b is an integer from 0 to 50, c is an integer from 1 to 100, m is an integer from 1 to 50, R2 is an aliphatic, linear or branched hydrocarbon radical with 1 to 30 carbon atoms, Y is hydrogen, SO.sub.3M, —SO.sub.2M, —PO.sub.3M.sub.2, —CH.sub.2COOM and M is hydrogen or a cation. Additional additives may be present.

Provided herein are color charts and water color pigment solutions useful, for example, in the calibration of reflectance-based diagnostic analyzers.

Improved sensor compositions comprising a dye are provided. The compositions are generally characterized by at least partially immobilizing the dye on polymeric microparticles and dispersing in a dispersion medium. The dye may comprise an oxygen, humidity, carbon dioxide, temperature, or pH-responsive dye. Also provided is a sensor patch comprising a substrate and the sensor composition comprising a dye.