Abstract: This invention relates to a process for the preparation of quinacridone pigments by(a) heating, at a temperature of about 80.degree. C. to about 145.degree. C., a reaction mixture containing(i) 2,5-dianilinoterephthalic acid, a 2,5-dianilino-3,6-dihydroterephthalic acid ester, and/or a derivative thereof,(ii) about 3 to about 15 parts by weight, per part of component (a)(i), of a dehydrating agent, and(iii) about 0.

Abstract: A red pigment comprising: an iron oxide plate type particle, an aluminum compound layer which contains at least aluminum oxide and which is formed on the iron oxide particle, and the optical thickness of the aluminum compound layer being 150-500 nm. The red pigment according to the present invention has excellent color tone with high chroma from the orange to the blue red and moreover, and excellent stability.

Abstract: Naphthalocyanines of the general formula I ##STR1## where the variables have the following meanings: R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are each independently of the others hydrogen, hydroxyl or C.sub.1 -C.sub.20 -alkyl or C.sub.1 -C.sub.20 -alkoxy, whose carbon chains may each be interrupted by from 1 to 4 oxygen atoms in ether function and which may be phenyl-substituted,R.sup.9, R.sup.10, R.sup.11 and R.sup.12 are each independently of the others hydrogen, halogen or C.sub.1 -C.sub.20 -alkyl or C.sub.1 -C.sub.20 -alkoxy, whose carbon chains may each be interrupted by from 1 to 4 oxygen atoms in ether function,Me is two hydrogen atoms, two univalent metal atoms or a bivalent metal atom with or without further substituents for valence saturation,are pigments with isometric particles and a particle size distribution from 10 to 300 nm.

Abstract: A process for the preparation of acicular .alpha.-iron oxide hydrate which comprises oxidizing a slurry of ferrous hydroxide having an excessive alkali concentration of 1.0 mol/l or above with an oxygen-containing gas, interrupting oxidation, adding an excessive quantity of an aqueous solution of a salt of aluminate, homogenizing and stirring the resulting mixture, again oxidizing it with an oxygen-containing gas to obtain a slurry containing free aluminate ion and .alpha.-iron oxide hydrate, homogenizing and stirring the slurry, then neutralizing and aging it, and washing and drying it.

Abstract: Silica sols which have a large alkali excess, i.e. a low molar ratio SiO.sub.2 to M.sub.2 O, and which contain silica particles with a high specific surface area. The silica sols can be prepared through acidification of a water glass solution and subsequent alkalization of the acid sol to the molar ratio in question. The sols are particularly suitable for use as additives, in combination with cationic polymers, in papermaking.

Abstract: A plastic molding composition based on an organic thermoplastic polymer containing a black mineral pigment suitable as a material for the preparation of shaped articles which can be provided with symbols by exposure to laser radiation. The black pigment used is in particular animal charcoal, and the thermoplastic polymer is in particular a polyoxymethylene.

Abstract: The physical and chemical properties of a pigment-containing, water-based lacquer dispersion are improved by adding thereto a partial ester of an oligoglycerol obtained by condensation of 2 to 20 moles of glycerol with a C.sub.2 -C.sub.18 fatty acid. The partial ester may be ethoxylated and/or propoxylated, and the fatty acid may be hydroxy substituted.

Abstract: Pigment formulations contain a) a finely divided pigment, b) at least one colorant which has at least one external basic group, c) at least one acidic and/or neutral phosphoric ester and d) if required, further assistants conventionally used in such formulations. The formulations are used for pigmenting printing inks and lakes.The printing inks, pastes and lakes produced using the formulations have substantially better flow behavior than the inks and lakes obtained using prior art pigments.

Abstract: A pigment composition is disclosed, obtained from intaglio or engraved steel die printing ink wastes. The wastes containing pigment, ink resins, extenders, and other minor components, are dried, ground and sieved to give a dry pigment composition. This pigment composition is optionally blended with plasticizers to give a pasty composition.These compositions are useful to color and plasticize synthetic plastics materials such as sheetings, PVC leather and films.

Abstract: Copolymers having the general formula: ##STR1## are useful as compatibility, dispersion and grinding agents for aqueous pigmentary suspensions formulated from a mixture of mineral pigments, at least one of which is hydrated calcium sulfate. These suspensions are useful in papermaking.