Abstract: An organic-solvent dispersion containing fine polysilsesquioxane particles stably dispersed therein, which is obtained by adjusting the pH of an aqueous dispersion of fine polysilsesquioxane particles to 2 to 9, subsequently adding an organic solvent thereto, and then removing the water from the system; and an aqueous dispersion of fine polysilsesquioxane particles having an appropriate average particle diameter, which is obtained by adjusting the amount of a base catalyst to be used so as to be in a specific range. The process for producing an aqueous dispersion of fine polysilsesquioxane particles having a pH of 2 to 9 with an organic solvent.

Abstract: The present invention provides a process for producing 4,4?-dihydroxydiphenylsulfone of very high purity. In particular, the present invention provides a process for producing 4,4?-dihydroxydiphenylsulfone of high purity comprising the steps of subjecting phenol in combination with a sulfonating agent or phenolsulfonic acid to a dehydration reaction in the presence of an aromatic nonpolar solvent while suspending the resulting dihydroxydiphenylsulfone therein, mixing the reaction suspension with a polar solvent to at least partially dissolve the dihydroxydiphenylsulfone, and precipitating 4,4?-dihydroxydiphenylsulfone.

Abstract: An organic-solvent dispersion containing fine polysilsesquioxane particles stably dispersed therein, which is obtained by adjusting the pH of an aqueous dispersion of fine polysilsesquioxane particles to 2 to 9, subsequently adding an organic solvent thereto, and then removing the water from the system; and an aqueous dispersion of fine polysilsesquioxane particles having an appropriate average particle diameter, which is obtained by adjusting the amount of a base catalyst to be used so as to be in a specific range. The process for producing an aqueous dispersion of fine polysilsesquioxane particles having a pH of 2 to 9 with an organic solvent.

Abstract: The present invention provides a process for producing dihydroxydiphenylsulfone wherein trihydroxytriphenylsulfone and coloring impurities are effectively removed without altering the isomeric composition of dihydroxydiphenylsulfone. In particular, the present invention provides a process for producing dihydroxydiphenylsulfone comprising the steps of dissolveing or suspending in an aqueous solvent crude dihydroxydiphenylsulfone containing trihydroxytriphenylsulfone, adjusting the pH to 5–7, optionally cooling, and separating the crystalline dihydroxydiphenylsulfone thus precipitated.

Abstract: The present invention provides a process for producing 4,4?-dihydroxydiphenylsulfone of very high purity. In particular, the present invention provides a process for producing 4,4?-dihydroxydiphenylsulfone of high purity comprising the steps of subjecting phenol in combination with a sulfonating agent or phenolsulfonic acid to a dehydration reaction in the presence of an aromatic nonpolar solvent while suspending the resulting dihydroxydiphenylsulfone therein, mixing the reaction suspension with a polar solvent to at least partially dissolve the dihydroxydiphenylsulfone, and precipitating 4,4?-dihydroxydiphenylsulfone.

Abstract: A thermal recording material includes a thermosensitive coloring layer, which is made by applying a dispersion liquid, in which the developer and a coloring dye are dispersed, onto a supporting base, and then drying the base. The developer contains 4,4?-dihydroxydiphenyl sulfone as a major component; and 2,4?dihydroxydiphenyl sulfone, the 4,4?-dihydroxydiphenyl sulfone and the 2,4?-dihydroxydiphenyl sulfone being contained at a weight ratio greater than 90:10 and no more than 100:0, and the developer containing phenolsulfonic acid phenyl ester no more than 1.5% by weight with respect to a sum quantity of the 4,4?-dihydroxydiphenyl sulfone and the 2,4?-dihydroxydiphenyl sulfone. The present invention thus provides a thermal recording material causing less surface texture fogging and is superior in preservation ability, and also provides a developer suitably used as a component of the thermal recording material.

Abstract: The present invention provides a process for producing a mixture of dihydroxydiphenylsulfone isomers containing 2,4?-dihydroxydiphenylsulfone, the process comprising heating 4,4?-dihydroxydiphenylsulfone or a mixture of dihydroxydiphenylsulfone isomers containing at least 85 wt. % of 4,4?-dihydroxydiphenylsulfone in the presence of phenol and sulfuric or sulfonic acid.

Abstract: The present invention provides a process for producing dihydroxydiphenylsulfone wherein trihydroxytriphenylsulfone and coloring impurities are effectively removed without altering the isomeric composition of dihydroxydiphenylsulfone. In particular, the present invention provides a process for producing dihydroxydiphenylsulfone comprising the steps of dissolveing or suspending in an aqueous solvent crude dihydroxydiphenylsulfone containing trihydroxytriphenylsulfone, adjusting the pH to 5-7, optionally cooling, and separating the crystalline dihydroxydiphenylsulfone thus precipitated.

Abstract: The present invention provides a process for producing a mixture of 4,4?- and 2,4?-dihydroxydiphenylsulfones comprising heating trihydroxytriphenyldisulfone or a mixture of dihydroxydiphenylsulfone isomers containing trihydroxytriphenyldisulfone in the presence of phenol and an acid catalyst.

Abstract: The present invention provides a process for producing a mixture of dihydroxydiphenylsulfone isomers containing 2,4′-dihydroxydiphenylsulfone, the process comprising heating 4,4′-dihydroxydiphenylsulfone or a mixture of dihydroxydiphenylsulfone isomers containing at least 85 wt. % of 4,4′-dihydroxydiphenylsulfone in the presence of phenol and sulfuric or sulfonic acid.

Abstract: The present invention provides a process for producing a mixture of 4,4′- and 2,4′-dihydroxydiphenylsulfones comprising heating trihydroxytriphenyldisulfone or a mixture of dihydroxydiphenylsulfone isomers containing trihydroxytriphenyldisulfone in the presence of phenol and an acid catalyst.

Abstract: A positive resist composition which comprises a 1,2-quinone diazide compound and an alkali-soluble resin containing a polyphenol compound (I) of the general formula:X--.alpha.--H (I)wherein x is a group of the formula: ##STR1## and .alpha. is a divalent group which comprises a repeating unit of the formula: ##STR2## in which n is a number of not less than 1; a, b, c, d, e and f are the same or different and a number of 0-3, provided that d+f is not less than 1; R.sub.1, R.sub.2 and R.sub.3 are the same or different and a C.sub.1 -C.sub.18 alkyl group, a C.sub.1 -C.sub.18 alkoxy group, a carboxyl group or a halogen atom; R.sub.4 is a hydrogen atom, a C.sub.1 -C.sub.18 alkyl group or an aryl group, which resist composition is sensitive to radiation and has good balance of sensitivity, resolving power and heat resistance.

Abstract: A positive resist composition which comprises, in admixture, a photosensitive 1,2-quinone diazide compound, an alkali-soluble resin to bind ingredients and polyphenol compound to control a dissolution rate in a developer having a molecular weight of not more than 550 and represented by the general formula: ##STR1## wherein a, b, c, d, e, and f are the same or different and a number of 0-3, provided that d+f is not less than 1, and provided that if b, d and f are 1, then at least one of a, c, and e is not 0; R.sub.1, R.sub.2 and R.sub.3 are the same or different and a C.sub.1 -C.sub.18 alkyl group, a C.sub.1 -C.sub.18 alkoxy group, a carboxyl group or a halogen atom; R.sub.4 is a hydrogen atom, a C.sub.1 -C.sub.

Abstract: A positive resist composition which comprises, in admixture, a photosensitive 1,2-quinone diazide compound, an alkali-soluble resin to bind ingredients and polyphenol compound to control a dissolution rate in a developer represented by the formula: ##STR1## wherein R is C.sub.1-18 or hydrogen, the composition is sensitive to radiation and has good balance of sensitivity, resolving power and heat resistance.

Abstract: A positive resist composition which comprises in admixture an alkali-soluble resin and, as a sensitizer, first and second quinone diazide sulfonic acid esters of a phenol compound, wherein(a) the first ester is a quinone diazide sulfonic acid diester of a phenol compound having not less than three hydroxyl groups which exhibits a pattern area that is not less than 40% of all pattern areas corresponding to the sensitizer in a high pressure liquid chromatography (HPLC) pattern measured with a primary detector using UV light having a wavelength of 254 nm, and(b) the second ester is a quinone diazide sulfonic acid ester that is a complete ester of a phenol compound having not less than two hydroxyl groups which exhibits a pattern area corresponding to not less than 5% and is less than 60% of all pattern areas corresponding to the sensitizer in the HPLC pattern.

Abstract: A quinone diazide sulfonic acid ester of a phenol compound of the general formula (I): ##STR1## wherein Y.sub.1, Y.sub.2, Y.sub.3 and Y.sub.4 are the same or different and each a hydrogen atom, an alkyl group, a halogen atom or a hydroxyl group, provided that at least one of Y.sub.1, Y.sub.2, Y.sub.3 and Y.sub.4 is a hydroxyl group; Z.sub.1, Z.sub.2, Z.sub.3, Z.sub.4, Z.sub.5 and Z.sub.6 are the same or different and each a hydrogen atom, an alkyl, an aryl group, a halogen atom or a hydroxyl group, provided that at least one of Z.sub.1, Z.sub.2, Z.sub.3, Z.sub.4, Z.sub.5 and Z.sub.6 is a hydroxyl group; X is ##STR2## in which R.sub.1 and R.sub.2 are the same or different and each a hydrogen atom, an alkyl group, an alkenyl group, a cyclo-alkyl group, an alkoxy group or an aryl group, provided that when at least one of R.sub.1 and R.sub.

Abstract: A quinone diazide sulfonic acid ester of a phenol compound of the general formula (I) or (II): ##STR1## wherein a, c and d are the same or different and a number of 0 to 3, provided that when a is 0 or 3, b is a number of 0 to 3 or when a is 1 or 2, b is 0, 1 or 2, and a+b and c+d are not less than 2; R and R' are the same or different and an alkyl group or an aryl group provides a positive resist composition having a high .gamma.-value.

Abstract: A process for preparing a positive resist composition, which process includes the steps of condensation reacting a quinone diazide sulfonyl halogenide with a phenol compound, mixing a condensation reaction mixture with a solution of an alkali-soluble resin in a resist solvent and removing impurities from the mixture, whereby the overall processing time can be shortened.

Abstract: A quinone diazide sulfonic acid ester of a phenol compound of the general formula (I): ##STR1## wherein Y.sub.1 and Y.sub.2 are each a hydrogen atom, an alkyl group or a hydroxyl group, provided that at least one of Y.sub.1 and Y.sub.2 is a hydroxyl group; Z.sub.1, Z.sub.2, Z.sub.3, Z.sub.4, Z.sub.5, Z.sub.6 and Z.sub.7 are the same or different and each a hydrogen atom, a hydroxyl group, an alkyl group, a cycloalkyl group, an aryl group or halogen atom, provided that at least two of Z.sub.1, Z.sub.2, Z.sub.3, Z.sub.4, Z.sub.5, Z.sub.6 and Z.sub.7 are hydroxyl groups; R.sub.1, R.sub.2 and R.sub.3 are the same or different and each a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group or an aryl group provides a positive resist composition having a high .gamma.-value.

Abstract: A novolak resin for a positive photoresist is provided herein, which resin is produced by the addition condensation reaction of a phenol with formaldehyde. This novolak resin has improved heat resistant and sensitivity properties and the thickness retention of the novolak resins are very high.