Abstract: The present invention provides a decolorized red phosphorus composition capable of inhibiting coloring in dark red peculiar to red phosphorus even when kneaded with a resin or the like, modified red phosphorus used for the decolorized red phosphorus composition and a production method therefor, and a flame-retardant polymer composition using the decolorized red phosphorus composition. The modified red phosphorus includes red phosphorus particles (A) whose surfaces are coated with a modified resin film (F) containing white particles (B) having a whiteness of 70 or more, color particles (C) having a hue H of 30 to 80 in the Munsell color-system hue circle, and a binder resin (D). The decolorized red phosphorus composition includes a mixed powder containing the modified red phosphorus and white particles (B) having a whiteness of 70 or more. The flame-retardant polymer composition contains the decolorized red phosphorus composition and a polymer compound (I).

Abstract: An aqueous zinc nitrite solution which contains substantially no calcium (Ca) ions is provided, in which, in terms of the aqueous zinc nitrite [Zn(NO2)2] solution having an NO2 concentration of 10% by weight, the sodium (Na) ion concentration is 200 to 2000 ppm and the sulfate (SO4) ion concentration is 20 ppm or less in the solution. The aqueous zinc nitrite solution can be prepared by providing a zinc compound and an alkali nitrite as raw materials and subjecting the raw materials to electrolytic synthesis through a double decomposition reaction using an ion-exchange membrane as a diaphragm. As the aqueous zinc nitrite solution is provided, an extremely efficient metal surface treatment is made possible which has a reduced amount of sodium ions. In particular, it contains substantially no sulfate ions and no calcium ions.

Abstract: A red phosphorus base flame retardant for an epoxy resin, which can suppress oxo acid of phosphorus from eluting from red phosphorus and can impart remarkable flame retardancy to an epoxy resin for a semiconductor sealing material. The red phosphorus base flame retardant for an epoxy resin comprises coated red phosphorus which has the surface of red phosphorus particles coated with a thermosetting resin containing an anhydrous zinc compound or the surface of red phosphorus particles coated with an inorganic substance and further coated with a thermosetting resin containing an anhydrous zinc compound. The coated red phosphorus has properties that a slurry having the coated red phosphorus dispersed in 10% by weight into water at 20° C. has an electric conductivity of 30 &mgr;s/cm or below, the slurry having been left standing at 80° C. for 20 hours has an electric conductivity of 150 &mgr;s/cm or below, and when 80 ml of water is added to 8 g of the coated red phosphorus and heated at 80 ° C.

Abstract: An aqueous zinc nitrite solution contains as impurities 10 ppm or less of sodium (Na) and 100 ppm or less of sulfate ions (SO4) when the aqueous solution has a concentration of zinc nitrite [Zn(NO2)2] of 10% by weight in terms of NO2. Also, disclosed is a method for preparing an aqueous zinc nitrite solution, including a first step of reacting zinc sulfate with calcium nitrite to form an aqueous zinc nitrite solution and a second step of purifying the aqueous zinc nitrite solution.

Abstract: The present invention is to provide a metal surface-treating method which is capable of forming a zinc phosphate coat suitable for the cationic electrodeposition coating of a metallic shaped product, particularly a metallic shaped product having both an iron type metallic surface and a zinc type metallic surface and is suited to a closed system.

Abstract: This invention provides a metal surface-treating method which comprises a chemical conversion step of dipping a substrate in an acidic aqueous zinc phosphate solution, and using an aqueous zinc nitrite solution as an accelerator, said aqueous zinc nitrite solution being substantially free of calcium ion and containing 0 to 6500 ppm of sodium ion and 0 to 20 ppm of sulfate ion in case of assuming the concentration of zinc nitrite [Zn(NO2)2] therein to be 10 weight % as NO2.

Abstract: The fine spherical silica having a particle size distribution in which maximum particle diameter is 24 &mgr;m, average particle diameter is 1.7 to 7 &mgr;m, and the proportion X1 of particles having a particle diameter of 3 &mgr;m or less in the total particles is 100/D50 to (18+100/D50) wt %, and the viscosity at 50° C. of a mixture obtained by blending a maximum of 80 wt % of the fine spherical silica with a liquid epoxy resin or silicone resin at room temperature is 20 Pa·s or less is provided. The spherical silica is useful as a filler for sealing resin composition which has excellent gap permeability and seals slight gaps, between a substrate and an IC chip and has high reliability.

Abstract: The present invention relates to a fused spherical silica having a maximum particle size of 45 &mgr;m, an average particle size of 2 to 10 &mgr;m, and a ratio of a specific surface area Sw1 of the particles to a theoretical specific surface area Sw2 of the particles, Sw1/Sw2, of 1.0 to 2.5, the surface of the particles being smooth. The present invention can provide a liquid sealing resin composition having sufficiently low viscosity for sealing a slight gap between a substrate and an IC chip and also having high reliability, and a fused spherical silica filler to be filled therein.

Abstract: This invention provides a metal surface-treating method

Abstract: An aqueous zinc nitrite solution contains as impurities 10 ppm or less of sodium (Na) and 100 ppm or less of sulfate ions (SO4) when the aqueous solution has a concentration of zinc nitrite [Zn(NO2)2] of 10% by weight in terms of NO2. Also, disclosed is a method for preparing an aqueous zinc nitrite solution, including a first step of reacting zinc sulfate with calcium nitrite to form an aqueous zinc nitrite solution and a second step of purifying the aqueous zinc nitrite solution.

Abstract: The present invention relates to fused spherical silica for liquid sealant which has a particle size distribution such that maximum particle size is 24 &mgr;m, average particle size is 2 to 7 &mgr;m, and the proportion of particles having a particle size of 1 &mgr;m or less is 1% by weight or less, and the silica has a BET specific surface area of 3 m2/g or less. Fused spherical silica filler of the present invention for liquid sealant can be blended with an epoxy resin or silicone resin which is liquid at normal temperature in high proportion, and can minimize the coefficient of linear expansion of a liquid sealing resin composition.