Abstract: A method method for laser welding a layered article wherein IR irradiation is passed through a composition containing a tetrabenzodiazadiketoperylene pigment or dye to the surface of an underlying substrate which contain an IR absorbing material, generating enough heat at the point of irradiation to melt together the two materials.

Abstract: A method for laser marking a substrate which method comprises exposing a composition comprising a tetrabenzodiazadiketoperylene pigment to laser radiation to produce a fluorescent marking readily apparent under UV light is disclosed. Many of the tetrabenzodiazadiketoperylenes herein are novel. This method can yield fluorescent markings which are not readily apparent under ambient light. A method for producing non-fluorescent laser marked substrates containing tetrabenzodiazadiketoperylene dyes is also disclosed.

Abstract: The invention is directed to a method or use of 2,9-dichloro-quinacridone as an alpha crystal phase inhibitor and optionally, 4,11-dichloroquinacridone during the beta-quinacridone or gamma-quinacridone crude pigment particle size reduction processes. The invention is also directed to solid solutions of quinacridone comprising about 98 to about 80 weight % gamma or beta-quinacridone, about 0.1 to about 10 weight % 2,9-dichloroquinacridone and about 0.1 to about 10 weight % 4,11-dichloroquinacridone.

Abstract: A method for producing fluorescent markings on a substrate which method comprises exposing a composition comprising a polymer and an organic pigment to a heat source, such as laser radiation, to produce a fluorescent markings which are not discernable when viewed under ambient visible light but readily apparent under UV light is disclosed. The method produces novel compositions wherein a fluorescent form of a pigment is present at a higher concentration in defined domains relative to the remainder of the composition. The novel polymer composition is particularly useful in security marking applications.

Abstract: Dialkyl succinylsuccinates are prepared in a pure form and in high yield by reacting an alkali metal alcoholate with an excess of dialkyl succinate under anhydrous conditions followed by isolation of the di(alkali metal) salt of the dialkyl succinylsuccinate and then neutralization of the salt with acid. The resulting dialkyl succinylsuccinate is isolated or used without isolation as an intermediate in the production of quinacridone pigments. The disclosed process provides for high yields and reduced organic waste compared with known processes.

Abstract: Oxo-polycarboxylic acids act as set control agents, preferably as set retarders for plasters. Examples of usable acids are 2,2,6,6-tetra(.beta.-carboxyethyl)cyclohexanone, 2,2-di(.beta.-carboxyethyl)-3,5,5-trimethylcyclohexanone or 3-acetyl-3(.beta.-carboxyethyl)-pimelic acid. Also the salts of these acids are usable. The set control agents are added to the plaster in amounts of 5 to 5000 ppm.