Abstract: Provided are amorphous silica particles for application to industrial fields where there are increasing desires for high purity and colorlessness. The amorphous silica particles are produced through the steps of hydrolysis of an alkoxide, vacuum drying, and firing. The amorphous silica particles have been reduced in coloration and in Fe content, which is causative of coloration of the silica, and can meet the desires. The amorphous silica is characterized by having an Fe content of 20 ppm or less.

Abstract: Provided are amorphous silica particles for application to industrial fields where there are increasing desires for high purity and colorlessness. The amorphous silica particles are produced through the steps of hydrolysis of an alkoxide, vacuum drying, and firing. The amorphous silica particles have been reduced in coloration and in Fe content, which is causative of coloration of the silica, and can meet the desires. The amorphous silica is characterized by having an Fe content of 20 ppm or less.

Abstract: Provided is a calcined silica particle and a manufacturing method of the same, the calcined silica particle having a low hygroscopicity, and a narrow range of particle size distribution, and substantially even particle diameter, and containing little of large-diameter fused aggregation of the particulates of the calcined silica particle. A silica particle is obtained by hydrolyzing and condensing a hydrolyzable silicon compound in an organic solvent containing water, for example, at a reaction temperature ranging from 0° C. to 50° C., and then dried. Then, the silica particle is calcined at a temperature ranging from 1000° C. to 1200° C. It is preferable that the organic solvent contains the silicon compound in a range between 0.05 to 1.2 mol/L, the water in a range between 2.0 to 25.0 mol/L, and a catalyst in a range between 0.8 to 9.4 mol/L. The calcined silica particle has an average particle diameter ranging between 0.04 ?m and 5.0 ?m; a standard deviation of the average particle diameter of 1.

Abstract: A grain aggregate is formed by bonding a plurality of cross-linking polymeric grains via a substance (binder) having a reactive functional group, and alternatively, the grain aggregate is formed by bonding at least two different types of a plurality of grains, thus providing the grain aggregate having the improved heat resistance, solvent resistance, strength and light-diffusing properties. Further, a light-diffusing agent made up of the grain aggregate has the improved light-diffusing properties. Therefore, when applying a light-diffusing mold article including the light-diffusing agent to, for example, a backlight of a liquid crystal display device, high brightness and a wide angle of visibility can be attained. Further, by spray drying of a dispersion liquid containing the grain aggregate, the grain aggregate can be produced with ease.

Abstract: Provided is a calcined silica particle and a manufacturing method of the same, the calcined silica particle having a low hygroscopicity, and a narrow range of particle size distribution, and substantially even particle diameter, and containing little of large-diameter fused aggregation of the particulates of the calcined silica particle. A silica particle is obtained by hydrolyzing and condensing a hydrolyzable silicon compound in an organic solvent containing water, for example, at a reaction temperature ranging from 0° C. to 50° C., and then dried. Then, the silica particle is calcined at a temperature ranging from 1000° C. to 1200° C. It is preferable that the organic solvent contains the silicon compound in a range between 0.05 to 1.2 mol/L, the water in a range between 2.0 to 25.0 mol/L, and a catalyst in a range between 0.8 to 9.4 mol/L. The calcined silica particle has an average particle diameter ranging between 0.04 &mgr;m and 5.

Abstract: A grain aggregate is formed by bonding a plurality of cross-linking polymeric grains via a substance (binder) having a reactive functional group, and alternatively, the grain aggregate is formed by bonding at least two different types of a plurality of grains, thus providing the grain aggregate having the improved heat resistance, solvent resistance, strength and light-diffusing properties. Further, a light-diffusing agent made up of the grain aggregate has the improved light-diffusing properties. Therefore, when applying a light-diffusing mold article including the light-diffusing agent to, for example, a backlight of a liquid crystal display device, high brightness and a wide angle of visibility can be attained. Further, by spray drying of a dispersion liquid containing the grain aggregate, the grain aggregate can be produced with ease.

Abstract: The present invention provides a thermosetting resin potting composition with low melt viscosity and good flowability even though it contains large amount of an inorganic filler containing sphere silica powder as a main component. With this construction, the present invention has solved the problem residing in the prior art that, when the content of an inorganic filler is increased, the viscosity of a potting composition is increased and its flowability is lowered. In the present invention, the sphere silica particles in the inorganic filler have at least one particle group, and the particle group has an average particle diameter of 0.01 to 10 &mgr;m and a coefficient of particle diameter variation of 10 percent or smaller. More preferably, the sphere silica particles have two or more particle groups. In this case, the average particle diameter of the larger particle group is 1.4 times or larger than that of its adjacent and smaller particle group.

Abstract: Provided is a silica base particle having an average particle diameter of 0.01 to 10 .mu.m, wherein carboxylic esters are present on the surface of the above particle in a proportion falling in a range of 0.05 to 10% by weight based on the weight of the above particle. A polyester film containing the above silica base particles shows an excellent lubricant property and scratch resistance.

Abstract: A process for preparing an aqueous resin dispersion includes the steps of copolymerizing a polymeric monomer whose ratio of (meth) acrolein to a total amount of the (meth) acrolein and a vinyl monomer is in the range from 10 weight % to 80 weight % in an organic solvent to obtain a copolymer solution, dispersing the obtained copolymer solution in an aqueous medium and removing an unreacted (meth) acrolein. Since the above process can extremely reduce contents of the unreacted (meth) acrolein and of an oligomer whose number-average molecular weight is less than 1000, an aqueous resin dispersion where problems of a pungent smell, toxicological properties, etc. due to the (meth) acrolein and the oligomer are eliminated can be provided.

Abstract: In a method for the production of cyclohexanecarboguanamine by the reaction of cyanocylohexane with dicyandiamide in an organic solvent possessing a hydroxyl group in the molecular unit thereof at a temperature in the range of 90.degree. to 200.degree. C. in the presence of a basic catalyst, the improvement which comprises carrying out the reaction using 0.60 to 0.95 mol of dicyandiamide per mol of cyanocylohexane in an atmosphere substantially incapable of producing any effect of oxygent.

Abstract: A method for the production of methylolaminotriazine condensate by the reaction of cyclohexanecarboguanamine (A) and formaldehyde (B), which method comprises preparing a solution of formaldehyde (B) or a solution containing cyclohexanecarboguanamine (A) and formaldehyde (B) in such amounts that the molar ratio of (A)/(B) will be not more than 1/2.5, keeping the temperature of said solution in the range of 55.degree. to 150.degree. C. and, at the same time, gradually supplying cyclohexanecarboguanaimine (A) thereto.

Abstract: In a method for the production of cyclohexanecarboguanamine by the reaction of cyanocyclohexane with dicyandiamide in an organic solvent possessing a hydroxyl group in the molecular unit thereof at a temperature in the range of 90.degree. to 200.degree. C. in the presence of a basic catalyst, the improvement which comprises carrying out the reaction using 0.60 to 0.95 mol of dicyandiamide per mol of cyanocyclohexane in an atmosphere substantially incapable of producing any effect of oxygen.