Abstract: The object of the present invention is to provide silica particles which are surface-treated with a silicon compound uniformly and have improved surface characteristics and affinity with a resin. The silica particles according the present invention are surface-treated with a specific silicon compound, wherein C/Si ratio from X-ray photoelectron spectroscopy (XPS) is not less than 0.05.

Abstract: The object of the present invention is to provide silica particles which are surface-treated with a silicon compound uniformly and have improved surface characteristics and affinity with a resin. The silica particles according the present invention are surface-treated with a specific silicon compound, wherein C/Si ratio from X-ray photoelectron spectroscopy (XPS) is not less than 0.05.

Abstract: The present invention provides an amino resin composite particle in which an inorganic compound is fixed (firmly adhered) on a surface of an amino resin particle, for example, an amino resin composite particle, in which a child particle made of the inorganic compound is fixed on a mother particle made of the amino resin particle, and a method of easily and inexpensively producing the amino resin composite particle. After an amino compound such as benzoguanamine is reacted with formaldehyde, so as to prepare a reaction mixture containing an amino resin precursor to be the mother particle, an emulsion of the reaction mixture and an aqueous solution of an emulsifier, and an aqueous dispersion of the inorganic compound, such as silica powder, to be the child particle are mixed with a shear force application, so as to emulsify them to have an emulsion thereof. The emulsion is hardened by adding a catalyst.

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: A process for producing amino resin particles includes: a reaction process for obtaining a reaction solution containing an amino resin precursor which is obtained by a reaction of an amino compound with formaldehyde, and having a viscosity in a range of from 2×10−2 Pa·s to 5.8×10−2 Pa·s at a temperature in a range of from 95° C. to 98° C.; an emulsion process for obtaining an emulsion by emulsifying the reaction solution; and a curing process for curing the amino resin precursor in the emulsion state by adding a catalyst to the emulsion. With this producing process, it is possible to readily produce amino resin particles with an essentially uniform particle size (narrow particle size distribution).

Abstract: The present invention provides an amino resin composite particle in which an inorganic compound is fixed (firmly adhered) on a surface of an amino resin particle, for example, an amino resin composite particle, in which a child particle made of the inorganic compound is fixed on a mother particle made of the amino resin particle, and a method of easily and inexpensively producing the amino resin composite particle. After an amino compound such as benzoguanamine is reacted with formaldehyde, so as to prepare a reaction mixture containing an amino resin precursor to be the mother particle, an emulsion of the reaction mixture and an aqueous solution of an emulsifier, and an aqueous dispersion of the inorganic compound, such as silica powder, to be the child particle are mixed with a shear force application, so as to emulsify them to have an emulsion thereof. The emulsion is hardened by adding a catalyst.

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: The invention offers (meth)acrylic crosslinked fine particles, with excellent thermal resistance, which are suitably used as, for example, an anti-blocking agent or another additive in food packaging material and a method of manufacturing such particles. The invention involves (1) suspension polymerization of a monomer composition containing methyl methacrylate or another (meth)acrylic monomer using a lauroyl peroxide or another organic peroxide (polymerization initiator) and (2) aging of a polymerized product obtained in the polymerization at a temperature of from 80° C. to 95° C. for at least 1.5 hours. Hence, (meth)acrylic crosslinked fine particles with a crosslinking structure can be obtained which contain a residue of the (meth)acrylic monomer at a concentration not more than 2000 ppm and start thermally decomposing at a temperature not less than 260° C. and which more preferably have an average diameter of from 0.1 &mgr;m to 500 &mgr;m.

Abstract: A process for producing amino resin particles includes: a reaction process for obtaining a reaction solution containing an amino resin precursor which is obtained by a reaction of an amino compound with formaldehyde, and having a viscosity in a range of from 2×10−2 Pa.s to 5.8×10−2 Pa.s at a temperature in a range of from 95° C. to 98° C.; an emulsion process for obtaining an emulsion by emulsifying the reaction solution; and a curing process for curing the amino resin precursor in the emulsion state by adding a catalyst to the emulsion. With this producing process, it is possible to readily produce amino resin particles with an essentially uniform particle size (narrow particle size distribution).

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 method for the recovery of microfine suspended particles from a suspension medium, characterized by subjecting a polymeric monomer suspended in a suspension medium to suspension polymerization thereby forming microfine globular particles in the suspension solution, adding microfine water-insoluble particles to said suspension solution of microfine globular particles thereby inducing cohesion of said microfine globular particles, and separating said microfine globular particles in the form of an aggregate from said suspension solution filtration.

Abstract: A method for the production of microfine colored particles, characterized by subjecting a polymeric monomer suspended in a suspension medium to suspension polymerization in the presence of a coloring agent and/or a magnetic powder thereby forming microfine globular colored particles possessing an average particle diameter in the range of from 3 to 50 .mu.m, heat treating said microfine globular colored particles with water as a heating medium at a temperature in the range of from 50.degree. C. to 130.degree. C. thereby inducing fusion of said particles and giving rise to blocks of fused particles, and then disintegrating said blocks of particles to an average particle diameter substantially equal to the average particle diameter of said microfine globular colored particles existent prior to said fusion.