Abstract: A phase plate is superposed on a sample, and this phase plate is so adjusted that the phase difference of the total retardation of the sample and the phase plate is integral times 2.pi. with respect to a measuring beam of a first wavelength, so that retardation can be correctly measured even if an order is increased. In this state, a measuring beam of a second wavelength which is approximate to the first wavelength is employed and two polarizing plates maintaining polarizing directions in parallel nicol relation are singularly rotated with respect to the sample which is arranged therebetween. The ratio Im/Io between maximum value Io and minimum value Im of currently transmitted light intensity is applied to a previously prepared relation between the order n of retardation and this ratio Im/Io to derive the order of retardation of the sample, to thereafter obtain correct retardation.

Abstract: Disclosed is an electrostatic recording medium comprising an electroconductive support and a dielectric layer formed on the electroconductive support and containing an insulating resin and a pigment, characterized in that the pigment comprises kaolin having a quartz content of not more than 2% by weight and that the dielectric layer has, on the surface thereof, projections based on the pigment and having an equivalent diameter of 5-15 um as spacers.

Abstract: Disclosed is a heat-sensitive recording material comprising a support and a heat-sensitive recording layer, characterized in that an intermediate layer is formed between the support and the heat-sensitive recording layer wherein the intermediate layer comprises a pigment having an apparent specific gravity of about 0.7 g/cm.sup.3 or less and a polymeric substance having a glass transition temperature of 0.degree. C. or lower as a binder.

Abstract: Disclosed is a two-color heat-sensitive recording material which comprises a base sheet and a recording layer of single-layer or multi-layer structure formed on the base sheet, the recording layer comrising:(a) a diazonium salt,(b) a basic leuco dye,(c) a 2-hydroxy-3-naphthoic acid derivative which acts as a coupler compound for causing the diazonium salt to develop color when heated and which also acts as a color developing material for causing the basic leuco dye to develop color when heated, and(d) a basic substance, wherein the diazonium salt and the basic leuco dye each form a color upon application of heat, thereby giving the first image of a mixed color, and, then, after irradiation of an active ray to decompose the diazonium salt, the basic leuco dye alone forms its own color upon application of heat, thereby giving the second image whose color is different from the mixed color of the first image.

Abstract: This invention relates to recording materials comprising:(a) an organic phosphorus-iron compound having a bond of PO.sup.- and/or PS.sup.- with Fe.sup.+++ in the molecule and(b) a ligand compound capable of reacting with the organic phosphorus-iron compound to form a complex.

Abstract: In a microencapsulation process which causes hydrophobic core material containing an oil-soluble melamine-formaldehyde precondensate to emulsified in water or in a hydrophilic medium, and to form capsule wall film under conditions for promoting polycondensation, the process which is characterized in that said oil-soluble melamine-formaldehyde precondensate is 40 to 100% in a degree of formaldehyde substitution, 80 to 100% in alkylation degree, and 4 to 11 in hydrophobic degree.

Abstract: A process is described for preparing triarylmethane derivatives of a high purity in an extremely high yield from 3-phenylphthalide derivatives and aniline derivatives or indole derivatives with Friedel-Crafts type catalyst or Friedel-Crafts type catalyst and an oxidizing agent.

Abstract: An electrostatic record material comprising an electroconductive base sheet and a record layer formed on the base sheet and composed mainly of insulating resin, the record material being characterized in that the electroconductive base sheet has an electroconductive layer comprising (1) electron conductive particles produced by coating the particles of an inorganic compound with an electroconductive substance consisting of stannic oxide and a small amount of antimony and (2) a water-soluble adhesive composed of salts of a copolymer of at least 20 mole % of acrylic acid or methacrylic acid monomer.

Abstract: A coated synthetic paper adapted for offset printing is produced from a base paper sheet comprising fibrous material, at least 5% by weight of which is formed of polyolefinic pulp fibrils which are formed from a polyolefinic polymer and a hydrophilic polymer, said polyolefinic pulp fibrils having a specific surface area of at least 0.7 square meter/g. A microporous and discontinuous coating layer is formed on at least one of the surfaces of the base paper sheet using a coating composition having an adhesive component and a pigment component, at least 5% by weight of said pigment component being an organic polymer pigment in the form of finely divided particles.

Abstract: A sensitized sheet for a pressure sensitive copy system is obtained by coating the surface of a support with an acceptor composition comprising a particulate mixture comprising an organic acid substance selected from the group consisting of aromatic carboxylic acids and polyvalent metal salts thereof, and an organic high molecular compound. The above coating composition may further contain an inorganic solid particle such as oxides, hydroxides and carbonates of a polyvalent metal, and other mineral pigments. The coating procedure may be carried out with use of coating means mounted on the conventional paper machines.

Abstract: In an electrostatic recording material comprising an electroconductive base sheet and a dielectric layer supported thereon, the electrostatic recording material being characterized in that the dielectric layer contains 10 to 70 wt.% of non-conductive and non-photoconductive finely divided powder coated with organopolysiloxane.