JP2676849B2 - Silica composite fine particles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention attaches siliceous particles having a small particle size, preferably substantially spherical in a submicron unit, and having a uniform particle size on the surface of resin particles. The composite particles exist.

[Conventional technology]

Conventionally, it has been researched to modify the surface so as to have various properties by adhering small child particles to the surface of the mother particle to form a composite, but as the mother particle, polyethylene, polystyrene, nylon 6, nylon is used. Synthetic resin such as 12 or the like, pollen, starch, etc., as child particles polymethylmethacrylate, titania, hematite, zirconia,
Hydroxyapatite, iron powder, mica, etc. were used.

[Problems to be solved by the invention]

Among the above-mentioned child particles that the present inventors have tried so far, it is difficult to obtain inorganic particles having substantially spherical and uniform particle size, and organic particles are partially , There are those that satisfy the same condition, but there is a tendency to lack resistance to external environment such as heat, eventually, the surface is tightly covered with child particles while maintaining the spherical shape of the mother particles as composite particles, Moreover, it was difficult to realize a material having sufficient resistance.

As a result of intensive studies conducted by the present inventors in view of these points, a child particle having a true spherical shape and a narrow particle size distribution of uniform particle diameters, preferably by using submicron silica particles as child particles We succeeded in obtaining composite particles with heat resistance. Moreover, the obtained particles retain the true spheres of the mother particles because the silica particles that are the child particles are spherical and have a narrow particle size distribution, and are highly reactive due to the silanol groups on the surface of the silica particles, which are alkylated. It is possible to make the composite particles hydrophobic by, for example, coloring them with dyes, adsorbing various substances, and also separating and purifying them. The present invention has been achieved by finding that they are composite particles that can be expected to be used. That is, the gist of the present invention is that the particle size of the mother particles is about 1
Using a thermoplastic resin of ~ 500μ, substantially spherical as a child particle on its surface, the particle size is about 0.1 ~ 50μ, the particle diameter ratio of the mother particles and the child particles is 8: 1 or more spherical diameter It exists in the composite particles formed by adhering siliceous particles having a uniform structure.

The composite particle of the present invention is preferably a thermoplastic synthetic resin as a mother particle, that is, a portion that becomes a core, and specifically, particles of a normal thermoplastic resin such as polyethylene, nylon, vinyl chloride, polystyrene, polypropylene, and acrylic resin are handled. Although it is easy and easy to attach, it may be selected from a wide variety as long as silica particles which are child particles can be attached and fixed. . The size is suitably about 1 to 500μ, but about 1 to 250μ, especially about 1 to 100μ is preferable. Further, as the child particles used in the present invention, of the child particle size,
Preferably in the submicron order, particles with a uniform particle size distribution of a true spherical shape, for example, a standard deviation of 1.1 or less,
When it is more preferably 1.05 or less, it is possible to obtain a composite particle having a highly uniform sphericity with a very uniform surface, but depending on the desired surface condition of the composite particle, a siliceous particle having an appropriate particle size distribution. Can be used. Further, as the material of the child particles, silica is mainly used, or those obtained by further modifying such silica particles with a coupling agent,
Particles mainly composed of silica, such as particles of silicic acid compounds in which silanol groups are substituted with alkyl groups, vinyl groups, etc., are used. The size is usually selected from the range of about 0.1 to 50μ in particle size, more preferably about 0.1 to 1μ. The ratio of the particle diameters of the mother particles and the child particles is 8: 1 or more, preferably 10: 1 or more.

These two kinds of particles are mixed by a known mechanical mixing method to attach the child particles to the surface of the mother particles. Specifically, there are a dry simple mixing method using an automatic mortar and the like, a high-speed airflow impact method using a hybridizer, and the like, but a high-speed airflow impact method, that is, mixing particles at high speed with a hybridizer, mother particles by collision, The method of strengthening the interaction between the child particles and implanting the child particles on the surface of the mother particles can uniformly attach and fix the child particles on the surface of the mother particles,
desirable. The composite particles thus obtained may be further treated with a coupling agent or the like to modify the surface, and since the silanol groups on the surface of the silica particles are highly reactive, they may be colored with a dye. It is also possible to use as a separating agent. Furthermore, holding the spherical shape of the mother particles,
In addition, due to the fact that the surface has reactivity, toner, chromatographic separation agents, cosmetics, pharmaceuticals, test reagents, car wax,
These particles are useful in the fields of building materials, ceramics materials, paints, printing inks, etc. and have a wide range of applications.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto as long as the gist of the present invention is not exceeded.

Example 1 6 g of silica particles having a particle size of 0.6 μ and a standard deviation of 1.05 and high-density polyethylene particles having a particle size of 10 μ (made by Steel Chemical Industry Co., Ltd.)
14 g of flow beads ") was treated with a hybridizer (NHS-0 type manufactured by Nara Machinery Co., Ltd.) for 5 minutes at 50 ° C and 16,000 rpm. The surface of the resin particles as shown in Figs. In this way, composite particles having high sphericity with silica particles attached were obtained.

Example 2 9 g of silica particles used in Example 1 and high density polyethylene particles having a particle size of 15 μ (21 g of iron-made chemical “flow beads”)
Was treated with a hybridizer at 50 ° C. and 14,000 rpm for 5 minutes. As shown in FIG. 2, composite particles having a high sphericity in which silica particles were uniformly adhered to the surface of the resin particles were obtained.

〔The invention's effect〕

According to the present invention, it is possible to obtain composite particles having unique properties and having a wide range of applications.

[Brief description of the drawings]

1 and 2 are micrographs showing the particle structure of the composite fine particles of the present invention.

Claims (1)

(57) [Claims] 1. A thermoplastic resin having a particle size of about 1 to 500 μm is used as a mother particle, and the surface thereof has a substantially spherical shape as a child particle having a particle size of about 0.1 to 50 μm. Composite particles formed by adhering siliceous particles having a uniform particle diameter and having a particle size ratio of 8: 1 or more.