JP2015027653A - Method and device for manufacturing hollow particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for generating a large amount of hollow particles in a short time, without removal of core material.SOLUTION: In a process for preparing a microcapsule having internally capsulated liquid or solid with interfacial polymerization, gas pressure is applied to the internally capsulated liquid so that gas is excessively dissolved than under normal pressure environment. Consequently, foam formation in the internally capsulated liquid is facilitated during film formation under normal pressure environment, so that a hollow particle is manufactured resulting from the film formation with a gas phase being internally held.

Description

The present invention relates to a particle having a hollow structure and a manufacturing apparatus, which are manufactured by utilizing a foaming phenomenon when a gas is pressurized and decompressed from a state where gas is excessively dissolved in a liquid.

Hollow particles with a gas structure inside and a solid outside structure are low in density and can suppress the transmission of sound and heat, so they are used for lightening materials, soundproofing materials, and heat insulating materials that adjust the specific gravity of materials. It has been.

  As a conventional method for producing hollow particles, solid particles containing a substance that becomes a liquid or solid core (core substance) are generated, and the core substance is extracted from the solid particles by an operation such as pressurization or decompression to be hollow. There are a method (refer to Patent Documents 1 and 2) or a technique for vaporizing a core material to give a hollow structure (refer to Patent Document 3).

Moreover, as a method of directly creating hollow particles using bubbles, a method of polymerizing substances in a liquid phase around the bubbles on the surface of the bubbles to produce a solid film to form hollow particles (see Patent Document 4), liquid A method in which polymerization of substances in a phase is promoted by a catalyst contained in a gas phase to form hollow particles (see Patent Document 5), and droplets are formed while bubbles are stably present in droplets in which a membrane material is dissolved. A method of forming a hollow particle with a hollow structure by drying and precipitating a film material (see Patent Document 6), a gas containing a reactive gas that reacts with a liquid and causes film formation as fine bubbles in the liquid There is a method of supplying hollow particles (Patent Document 7).

JP 2002-105104 A Japanese National Patent Publication No. 9-508067 Japanese Patent Publication No. 3-79060 JP 2007-21315 A JP 2007-196223 A Japanese Patent Laid-Open No. 2007-75660 Japanese Patent Application Laid-Open No. 2011-245452

In the above background art, the method of hollowing out the core material contained in the solid particles by extraction or vaporization is difficult to control the pressure and heat of the hollowing process, and the deformation of the particles and the damage of the surface during the hollowing. It is a problem that is likely to occur.

In addition, in the method using bubbles in the background art described above, a hollowing step is not required, so that hollow particles can be easily produced, but the amount of hollow particles to be generated is small with respect to the amount of bubbles generated, and the yield is low. In addition, in the case of drying in liquid, it is a problem that preparation takes a long time. In addition, from the viewpoint of polymerization rate and foam maintenance, there are also problems that there are few choices of materials that can be made into hollow particles.

This invention makes it a subject to solve the said problem regarding the production | generation method of the particle | grains which have the conventional hollow structure by developing the production | generation method different from the past.

As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that a known microencapsulation technique, an interfacial polymerization method (in the emulsion containing different components in the dispersoid and the dispersion medium, different in each phase) In the process of preparing a microcapsule by a method in which components react with each other at the contact interface to form a microcapsule, the liquid that becomes the dispersoid is pressurized with a gas and passed through a process of dissolving the gas more than in a normal pressure environment. It has been found that bubbles are generated inside the dispersoid during film formation in a normal pressure environment, and hollow structure particles having a gas phase inside can be prepared after film formation. Regarding the generation of bubbles inside the dispersoid, the amount of gas dissolved in the liquid is proportional to the pressure (Henry's law). In a high-pressure environment, a larger amount of gas dissolves in the liquid than under atmospheric pressure. It utilizes the principle that when a saturated and dissolved liquid is depressurized to atmospheric pressure, a supersaturated dissolved gas is generated as bubbles.

With the particles having a hollow structure according to the present invention, the following effects can be obtained. (1) The core substance removing step is not necessary. (2) The minimum required apparatus is a simple configuration including only a pressure vessel, a droplet forming means, and a reaction tank, and hollow particles can be prepared easily and inexpensively. (3) Many of the bubbles generated in the core substance remain inside the particles.

It is the figure which showed the apparatus structure of this invention. 2 is an optical microscope image of particles having a hollow structure obtained in Example 1. FIG. 3 is an electron microscope image of particles having a hollow structure obtained in Example 2. FIG.

The present invention is a technique and apparatus that can easily generate particles with cavities held therein by the following steps. (1) The liquid held in the container is pressurized to atmospheric pressure or higher with a gas, and the gas is dissolved in the liquid more excessively than in an atmospheric pressure environment. (2) The pressurized liquid is discharged as droplets by the droplet forming means into the liquid held in the reaction tank, and the droplet is used as a dispersoid and the emulsion state using the liquid held in the reaction tank as a dispersion medium. To form. (3) The liquid and liquid droplets held in the reaction vessel react with each other in the components at the liquid droplet interface to form a film and become particles. In addition, by reducing the pressure inside the droplet under an atmospheric pressure environment, the gas is generated as a bubble in excess of the saturated state in the atmospheric pressure environment due to the pressurization operation, so that a hollow structure is imparted to the particles. The Hereinafter, the best mode for carrying out the present invention will be described with reference to FIG.

The best mode for carrying out the present invention will be described below. A liquid 3 in which the particulate material 2 is dissolved or dispersed is placed in the pressure vessel 1 and pressurized with a gas 4. The liquid 3 which is pressurized by the gas 4 and in which the gas 4 is excessively dissolved in the atmospheric pressure environment is discharged as droplets 6 by the droplet forming means 5 and collected in the reaction tank 7. The liquid droplet 6 is a liquid 9 in which the particle material 8 filled in the reaction vessel 7 is dissolved or dispersed. The material 8 comes into contact with the film to form fine particles 10. From the formation of the droplet 6 until the generation of the fine particles 10 is completed, a part of the gas 4 excessively dissolved by the pressurizing operation is generated as single or plural bubbles 11 inside the droplet 6 under the atmospheric pressure environment. By doing so, a hollow structure can be provided inside the fine particles 10.

The pressure vessel 1 is not particularly limited as long as the inside is maintained at atmospheric pressure or higher and can be sealed. However, the pressure glass bottle, the pressure glass tube, the stainless bottle, the stainless tube, the stainless tank, the fluororesin bottle, the pet Examples include bottles and aluminum bottles. The pressure to be pressurized is not particularly limited as long as it is equal to or higher than the atmospheric pressure, but is preferably in the range of atmospheric pressure to 15 MPa that can be implemented with a gas cylinder or the like, and particularly in the range of atmospheric pressure to 1 MPa that can be implemented with a compressor or the like. preferable. In addition, the holding time in the pressurized state is not particularly limited as long as the gas 4 is in the liquid 3 and the gas 4 is in excess of the saturated dissolved amount in the atmospheric pressure environment.

The combination of the particulate material 2 and the particulate material 8 is particularly limited as long as it is a combination of particulate materials that form a film by reaction such as polymerization, condensation, dehydration, cooling and solidification, water absorption, hydration, and hydrolysis when they come into contact with each other. Not, but sodium alginate and calcium chloride, 1,8-octanedicarbonyl chloride and 1,6-hexanediamine, L-lysine and terephthaloyl dichloride, acid chloride (adipic acid chloride, sebacoyl chloride, terephthalic acid chloride, etc. ) And polyamines (1,6 hexamethylenediamine, piperazine, rheridine, etc.), acid chlorides and polyphenols (2,2-bis (4-hydroxyphenyl) propane, etc.), isocyanates (hexamethylene diisocyanate, metaphenylene diisocyanate, Ruylene isocyanate, 2,4-tolylene diisocyanate, 3,3-dimethyl-diphenyl-4,4-diisocyanate, diphenylmethane-4,4 diisocyanate, triphenylmethane-triisocyanate, naphthalene-1,5-diisocyanate, etc.) or Examples include combinations of isothiocyanates (ethyl isothiocyanate, methyl isothiocyanate, benzyl isothiocyanate, allyl isothiocyanate, pyridine-3-isothiocyanate, etc.) and water or polyol or polyamine, polyisocyanate and polyamine, and the like. The liquid 3 in which the particulate material 2 is dissolved or dispersed and the liquid 9 in which the particulate material 8 is dissolved or dispersed are not particularly limited as long as they are liquid at normal temperature and normal pressure. Water, known oils (castor oil, salad oil) , Corn oil, soybean oil, sesame oil, rapeseed oil, safflower oil, coconut oil, palm oil, olive oil, liquid paraffin, silicone oil, etc., known organic solvents (hexane, benzene, toluene, diethyl ether, chloroform, ethyl acetate, Methylene chloride, tetrahydrofuran, acetone, acetonitrile, N, N-dimethylformamide, dimethyl sulfoxide, acetic acid, 1-butanol, 2-propanol, 1-propanol, ethanol, methanol, formic acid, etc.). Particularly preferred forms are known in at least one of the liquid 3 in which the particle material 2 is dissolved or dispersed or the liquid 9 in which the particle material 8 is dissolved or dispersed in order to improve the stability of coalescence and dispersion stability of the discharged droplets. It is preferable to dissolve the surfactant. Non-ionic, anionic, cationic and zwitterionic types may be used as the surfactant, polyvinyl alcohol, TWEEN 20, TWEEN 80, Triton X-100, sodium dodecyl sulfate, sodium cholate, Examples include sodium deoxycholate, hexadecyltrimethylammonium, bromide cetyltrimethylammonium bromide, dodecyltrimethylammonium bromide and the like. Further, when the particulate material 2 or the particulate material 8 is liquid at normal temperature and normal pressure, the particulate material in a liquid state may be used as it is. Moreover, one particle material of the combination mentioned above should just be enclosed with the pressure vessel 1, and the other material should just be hold | maintained at the reaction tank 7, and whichever may be enclosed with the pressure vessel 1. FIG.

The gas 4 used for pressurization of the pressure vessel 1 is not particularly limited as long as it is a gas at normal temperature and normal pressure, but air, hydrogen, nitrogen, oxygen, chlorine, fluorine, rare gas, ozone, carbon dioxide Ammonia, sulfur dioxide, hydrogen chloride, nitrogen dioxide, sulfur fluoride, hydrocarbons, halogenated hydrocarbons, and mixed gas mixtures of the gases are exemplified, and the gas is used as a diaphragm pump, gear pump, rotary pump, tube, etc. The inside of the pressure vessel 1 is pressurized by air supply from a pump or air supply from a pressure vessel such as a cylinder.

The droplet forming means 5 is not particularly limited as long as the liquid 3 can be discharged into the atmosphere as an independent droplet having a volume sphere equivalent diameter of 1 mm or less. Release from the pores, ultrasonic spray nozzle, spray These are appropriately selected from known droplet forming means such as nozzles and inkjet generation nozzles.

The reaction tank 7 that holds the liquid 9 in which the particulate material 8 is dissolved or dispersed is not particularly limited as long as the liquid can be held. Bottles, beakers, flasks using solid materials such as glass, metal, earthenware, and resin A water tank etc. are illustrated. Although not essential, temperature control means exemplified by hot plates, cool stirrers, heat exchangers, oil baths, etc., magnetic stirrers, vortex mixers, and homogenizers are used to control the temperature of the film formation reaction environment. It is desirable to provide the reaction tank 7 with means such as these.

10 mL of a 1% aqueous sodium alginate solution is placed in a 300 mL stainless steel pressure vessel, pressurized to 4 atmospheres with oxygen, and pressurized for 30 minutes to dissolve oxygen in the 1% aqueous sodium alginate solution. The pressurized 1% sodium alginate aqueous solution is discharged as droplets into 200 mL of 10% calcium chloride aqueous solution held in a 300 mL beaker using a stainless steel tube having an inner diameter of 0.3 mm. A 1% sodium alginate aqueous solution and a 10% calcium chloride aqueous solution form a gel-like insoluble film at the contact interface with each other, and a large number of alginate gel particles are generated in a 300 mL beaker. In addition, the 1% sodium alginate aqueous solution pressurized with oxygen inside the pressurized container is foamed under reduced pressure when forming droplets or gelling under an atmospheric pressure environment to form a gas phase region in the alginate gel particles.

As shown in FIG. 2, the alginate gel particles prepared through the above-described series of steps were confirmed to have single or plural cavities having an outer diameter of 100 μm to 500 μm and an inner diameter of 5 μm to 50 μm.

An aqueous solution in which 0.3 g of polyvinyl alcohol and 0.8 g of sodium hydroxide are dissolved in 30 mL of water and a solution in which 0.36 g of adipoyl chloride is dissolved in 10 mL of methylene chloride are placed in a 100 mL reagent bottle and stirred to obtain an emulsified state. . 40 mL of the emulsified dispersion is sealed in a 300 mL pressure vessel, and the inside is pressurized with air at 4 atm for 30 minutes to dissolve the air in the dispersion. The pressurized emulsified dispersion is sprayed onto a 4% hexamethylenediamine aqueous solution using a spray nozzle. A nylon film forms at the contact interface between adipoyl chloride and hexamethylene diamine, and a film forms around the methylene chloride droplets in the sprayed liquid. In the methylene chloride droplet, the pressurized air is depressurized to atmospheric pressure and generated as bubbles in the droplet.

The hollow nylon particles prepared through the above series of steps have an outer diameter of 10 μm to 1000 μm, and it was confirmed from the image of damaged particles shown in FIG.

Since the hollow particles obtained in the present invention can easily give a hollow structure inside the fine particles, they can be applied to industrial materials that absorb changes in thermophysical properties and sound and impact, and change the texture of the hollow structure. It can be used for various purposes such as application to foods that can be applied, application to cosmetics that can change the touch and texture, application to pharmaceuticals such as contrast media using signals by acoustic characteristics .

Claims (5)

In two different liquids having a characteristic of forming a film at the contact interface, one liquid is supplied as a droplet into the other liquid, and foamed inside the droplet when forming a film at the droplet interface to form particles. Hollow particles characterized by providing a hollow structure In two different liquids having the characteristic of forming a film at the contact interface, a pressure vessel capable of enclosing one liquid and a gas and holding it at atmospheric pressure or higher, a reaction vessel holding the other liquid, The apparatus for producing hollow particles according to claim 1, further comprising droplet forming means for supplying the liquid as fine droplets into the reaction vessel. Liquid droplets are generated by the means for foaming inside the liquid droplets, and the liquid that forms the liquid droplets by the liquid droplet forming means is pressurized to atmospheric pressure or higher before forming the liquid droplets to dissolve the gas and decompressed when forming the liquid droplets. The hollow particle production apparatus according to claim 1 and the hollow particle production apparatus according to claim 2, wherein the gas is dissolved under reduced pressure. 3. The hollow particles according to claim 1 and the hollow particles according to claim 2, wherein the droplet forming means is discharge into a gas or liquid from pores having an area equivalent diameter of 1 mm or less in the opening. manufacturing device The hollow particle according to claim 1 and the hollow particle production apparatus according to claim 2, wherein the fluid to which the droplets are supplied contains a surfactant.