Process for producing hollow microspheres and process for producing porous molded ceramic

A manufacturing method and hollow technology, applied in the preparation of microspheres, ceramic products, microcapsule preparations, etc., can solve the problems of adhesion, dispersion stabilizer particles falling off, damage, etc.

Inactive Publication Date: 2011-11-23
KUREHA KAGAKU KOGYO KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in order to heat and foam the water-containing filter cake, it is necessary to use a powder mixer to heat under mechanical shear, so it is easy to cause fusion and damage of thermally expandable microspheres and hollow microspheres
In addition, in the method of Patent Document 9, since the dispersion stabilizer particles are attached to the outer shell surface of the heat-expandable microspheres during polymerization, it is difficult to firmly attach other solid particles, and the attached dispersion stabilizer particles tend to fall off.

Method used

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  • Process for producing hollow microspheres and process for producing porous molded ceramic
  • Process for producing hollow microspheres and process for producing porous molded ceramic
  • Process for producing hollow microspheres and process for producing porous molded ceramic

Examples

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Embodiment

[0122] Examples and comparative examples are given below to describe the present invention more specifically, but the present invention is not limited to these examples. In the present invention, the measurement methods of physical properties and characteristics are as follows.

[0123] (1) Foaming ratio

[0124] 0.7 g of heat-expandable microspheres were placed in a Jill oven, and heated at a predetermined foaming temperature for 2 minutes to cause foaming (thermal expansion). The obtained hollow microspheres were put into a graduated cylinder, and the volume thereof was measured. The expansion ratio was calculated by dividing the volume of the hollow microspheres by the volume of the unexpanded heat-expandable microspheres. At this time, the foaming temperature was raised from 70° C. by 5° C. to foam at each temperature. The expansion ratio at the temperature at which the maximum expansion ratio was obtained under these conditions was defined as the maximum expansion rati...

Embodiment 1

[0163] Deionized water was added to the heat-expandable microspheres obtained in Preparation Example 1 to prepare 500 g of an aqueous slurry having a concentration of 1% by mass of the heat-expandable microspheres. 40 g of colloidal calcium carbonate (average particle diameter 50 nm) was added to this aqueous slurry, and then added to a polymerization tank with a capacity of 1.5 liters with a stirrer. While stirring the aqueous slurry, steam heated to a temperature of 150° C. was blown thereinto at a pressure of 0.48 MPa to heat and expand the heat-expandable microspheres. In the aqueous slurry after the foaming treatment, the foam particles (hollow microspheres) are dispersed without forming aggregates.

[0164] The foam particles in the aqueous slurry are filtered and washed with water. Thereafter, washing with water and filtration were repeated twice, followed by drying to collect foam particles (hollow microspheres). The foam particles have an average particle diameter o...

Embodiment 2

[0166] Foam particles (hollow microspheres) were produced in the same manner as in Example 1, except that 100 g of colloidal silica (40% by mass of solid content, 12 nm in average particle diameter) was used instead of 40 g of colloidal calcium carbonate. The foam particles have an average particle diameter of 53 μm and a specific gravity of 0.10 g / cm 3 . The total content of the inorganic substances contained in the foam particles was 85% by mass. The hollow microspheres obtained in this way remarkably suppress scattering into the air, and are excellent in miscibility with inorganic substances having high specific gravity.

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Abstract

The invention provides a process for producing hollow microspheres which comprises: a step (1) in which heat-expandable microspheres having a microcapsular structure comprising a shell formed from a thermoplastic resin and, encapsulated therein, a blowing agent capable of gasifying or generating a gas and a solid material having an average particle diameter or average major-axis length smaller than the average particle diameter of the heat-expandable microspheres are dispersed in a liquid dispersion medium to prepare a slurry; and a step (2) in which the heat-expandable microspheres are heated in the slurry to soften and thermally expand the shells thereof, thereby forming hollow microspheres having the solid material adherent to the surface of the softened shells.

Description

technical field [0001] The present invention relates to a method for manufacturing hollow microspheres in which solid materials such as microparticles and microfibers are firmly attached to the surface of the shell. Furthermore, the present invention relates to a method for producing a porous ceramic molded body using the hollow microspheres as a porous forming agent. Background technique [0002] Heat-expandable microspheres have a microcapsule structure in which a foaming agent capable of vaporizing or generating gas is enclosed in a shell formed of thermoplastic resin. Heat-expandable microspheres are also called heat-expandable microspheres or heat-expandable microcapsules. When the heat-expandable microspheres are heated to a temperature above the softening point of the thermoplastic resin forming the shell, they thermally expand due to vaporization of the blowing agent itself or pyrolysis gas of the blowing agent. The hollow microspheres which are hollow body particl...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J13/04C04B38/06C09K3/00
CPCC04B20/0024C04B38/0625C04B35/565C04B35/10C04B16/085C04B35/18C04B35/14B01J13/18C04B2111/00793C04B28/18C04B40/024B01J13/04C04B38/06C09C3/04C09K3/00
Inventor 江尻哲男佐竹义克
Owner KUREHA KAGAKU KOGYO KK
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