JP2006249150A - Manufacturing method of bell-structured resin particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method which can easily manufacture bell-structured resin particles which have nuclear fine particles included in the vacancies of the shells consisting of a resin. <P>SOLUTION: The manufacturing method of the bell-structured resin particles has the primary emulsification step wherein into a monomer solution containing a monomer component and a polymerization initiator, a dispersion of nuclear fine particles, in which the nuclear fine particles are dispersed in a polar solution insoluble in the monomer solution, is added and agitated to prepare an emulsion in which the droplets consisting of the dispersion of the nuclear fine particles are dispersed in the monomer solution; the secondary emulsification step wherein the above emulsion is added in a polar solution insoluble in the monomer solution and agitated to prepare an emulsion in which the droplets consisting of the monomer solution which occludes the dispersion of the nuclear fine particles are dispersed in the polar solution insoluble in the monomer solution; the polymerization step wherein the monomer component is polymerized to obtain resin particles occluding the dispersion of the nuclear fine particles; and the drying step wherein from the above resin particles the occluded polar solution is removed to obtain the bell-structured resin particles. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a method for producing bell structure resin particles that can easily produce bell structure resin particles in which core fine particles are encapsulated in pores of a shell made of resin.

In recent years, bell structures have attracted attention as damping materials and sound insulation plates used for the purpose of absorbing vibration and absorbing sound. The bell structure means a structure in which core fine particles smaller than the shell are encapsulated in the holes of the shell. When such a bell structure is irradiated with vibration or sound, the incident kinetic energy is converted into the motion of the nuclear particles in the vacancies of the shell and consumed. Can be attenuated. For example, Patent Document 1 describes a sound insulating plate including such a bell structure.

In Patent Document 1, the core fine particles are arranged in the pores of the porous plate-like body. For example, if particles having a bell structure (bell structure particles) are used, the bell structure particles are suspended on an appropriate binder. By making it turbid and coating, it is possible to easily manufacture a member imparted with vibration damping properties and sound insulation properties.
Patent Document 2 discloses a bell structure particle having a shell having a hollow portion and a nucleus that absorbs kinetic energy incident on the hollow portion from the outside.

As a method for producing such bell structure particles, for example, in Patent Document 2, an intermediate material having sublimation characteristics or evaporation characteristics is provided between a shell and a nucleus, and the intermediate material is heated to a predetermined temperature. Then, a method for forming a space between the shell and the nucleus inside the shell by sublimation or evaporation outside the shell is disclosed. However, such a method has a problem in that it is difficult to handle an intermediate material having sublimation characteristics or evaporation characteristics, and the process needs to be performed under special conditions.

Japanese Patent Laid-Open No. 9-226035 JP 2000-148156 A

An object of the present invention is to provide a method for producing bell structure resin particles, which can easily produce bell structure resin particles in which core fine particles are encapsulated in the pores of a shell made of resin in view of the above-described situation. And

In the monomer solution containing the monomer component and the polymerization initiator, the present invention adds and stirs a fine particle dispersion in which fine particles are dispersed in a polar solution insoluble in the monomer solution, A primary emulsification step of preparing an emulsion in which droplets of the nuclear fine particle dispersion are dispersed, and an emulsion in which droplets of the nuclear fine particle dispersion are dispersed in the monomer solution. A secondary emulsification step of preparing an emulsion in which droplets made of a monomer solution containing the nuclear fine particle dispersion are dispersed in a polar solution insoluble in the monomer solution by adding and stirring in the solution; and the monomer Polymerization step of polymerizing components to obtain resin particles enclosing the core fine particle dispersion, and removing the polar solution contained from the resin particles enclosing the core fine particle dispersion to produce bell structure resin particles A method for producing a tin structure resin particles having a get drying step.
The present invention is described in detail below.

In the method for producing bell structure resin particles of the present invention, a core particle dispersion in which core particles are dispersed in a monomer solution containing a monomer component and a polymerization initiator is added and stirred. And a primary emulsification step of preparing an emulsion (so-called W / O type emulsion: hereinafter also referred to as a primary emulsion) in which droplets of the nuclear fine particle dispersion are dispersed in the monomer solution.

The said monomer component comprises the shell part of the bell structure resin particle obtained by superposing | polymerizing.
The monomer component is not particularly limited, and examples thereof include aromatic vinyl monomers such as styrene, α-methylstyrene, p-methylstyrene, and p-chlorostyrene; vinyl esters such as vinyl acetate and vinyl propionate; vinyl chloride and chloride. And halogen-containing monomers such as vinylidene; ethylene, propylene, butadiene; acrylic monomers, and the like. These may be used alone or in combination of two or more. Among these, when an acrylic monomer is used, it is preferable because bell structure resin particles having a relatively high hydrophilicity and applicable to a wide range of uses can be obtained.

Examples of the acrylic monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, cumyl (meth) acrylate, cyclohexyl (meth) acrylate, and myristyl (meth) acrylate. , Alkyl (meth) acrylates such as palmityl (meth) acrylate, stearyl (meth) acrylate, isobornyl (meth) acrylate; (meth) acrylonitrile, (meth) acrylamide, (meth) acrylic acid, glycidyl (meth) acrylate, 2- Examples thereof include hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-acryloyloxyethylphthalic acid, itaconic acid, fumaric acid, dimethylaminomethyl methacrylate and the like.

Moreover, as the acrylic monomer, a polyfunctional monomer can be used. When a polyfunctional acrylic monomer is used, the mechanical strength of the resulting bell structure resin particles is improved. Examples of the polyfunctional acrylic monomer include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and trimethylolpropane. Di (meth) acrylates such as di (meth) acrylate; Tri (meth) acrylates such as trimethylolpropane tri (meth) acrylate, ethylene oxide modified trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, etc. Can be mentioned.

The polymerization initiator is not particularly limited and may be appropriately selected depending on the type of monomer component used. For example, benzoyl peroxide, lauroyl peroxide, dibutyl peroxydicarbonate, α-cumylperoxyneodecano Organic peroxides such as ate; azo initiators such as azobisisobutyronitrile; redox initiators and the like.

The monomer solution preferably contains a lipophilic emulsifier. By containing a lipophilic emulsifier, the emulsion stability of the primary emulsion can be further improved. The lipophilic emulsifier is not particularly limited. For example, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, glycerin fatty acid ester, polyglycerin fatty acid ester, propylene glycol fatty acid ester, etc. Is mentioned.

The blending amount of the lipophilic emulsifier in the monomer solution is not particularly limited, but a preferred lower limit is 0.01% by weight of the total amount of monomer components, and a preferred upper limit is 50% by weight. If it is less than 0.01% by weight, good primary emulsification may not be possible. If it exceeds 50% by weight, a large number of emulsifiers are mixed inside the polymer skeleton, and the strength of the resulting bell structure resin particles decreases. Sometimes. A more preferred lower limit is 0.1% by weight, and a more preferred upper limit is 20% by weight.

The monomer solution may further contain a non-polymerizable organic solvent. By containing a non-polymerizable organic solvent, the size of the pores in the shell of the resulting bell structure resin fine particles can be adjusted. The non-polymerizable organic solvent is not particularly limited, and examples thereof include butane, pentane, hexane, heptane, cyclohexane, toluene, xylene, ethyl acetate, methyl chloride, methylene chloride, chloroform, and carbon tetrachloride.

A blending amount of the non-polymerizable organic solvent in the monomer solution is not particularly limited, but a preferable upper limit with respect to 100 parts by weight of the monomer component is 400 parts by weight. If it exceeds 400 parts by weight, the strength of the resulting bell structure resin particles may be lowered. A more preferred upper limit is 100 parts by weight. The lower limit is not particularly limited.

The nuclear fine particle dispersion is obtained by dispersing nuclear fine particles in a polar solution insoluble in the monomer solution.
In addition, insoluble in this specification means that when mixed, they are completely separated to form a phase, and may be dissolved in a very small amount.
The polar solution insoluble in the monomer solution used in the primary emulsification step is not particularly limited as long as it is insoluble in the monomer solution, but water, polyols such as glycerin, and the like are preferable.

The polar solution insoluble with the monomer solution preferably contains an aqueous polymerization inhibitor. By containing the aqueous polymerization inhibitor, it is possible to suppress polymerization even when the monomer solution is slightly dissolved in the polar solution insoluble with the monomer solution.
Examples of the aqueous polymerization inhibitor include sodium nitrite, copper chloride, iron chloride, titanium chloride, and hydroquinone.

The core fine particles serve as nuclei of the resulting bell-shaped resin particles, and have a role of absorbing kinetic energy when the kinetic energy is incident on the bell-structure resin particles of the present invention.
The core fine particle is not particularly limited as long as it can be dispersed in the polar solution insoluble in the monomer solution. For example, polyacryl beads, polystyrene beads, polyvinyl chloride beads, polyethylene beads, polypropylene beads, carbon black, etc. Those composed of inorganic fine particles such as organic fine particles, titanium oxide, aluminum oxide, silicon carbide, silica, mica, calcium carbonate, barium sulfate, ferrite, fly ash, glass beads, glass powder, and tungsten powder are preferable. Of these, polyacryl beads, polystyrene beads, titanium oxide, aluminum oxide, silica, calcium carbonate and the like are more preferable.

The shape of the above-mentioned core fine particles is not particularly limited, but it is preferably close to a true sphere in order to facilitate the mobility of the obtained bell-shaped resin particles and to exhibit high vibration damping properties and sound insulation properties.
The particle diameter of the core fine particle is not particularly limited, but a preferable lower limit is 0.1 μm and a preferable upper limit is 2000 μm. If it is less than 0.1 μm, vibration absorption of the resulting bell structure resin particles may be deteriorated, and if it exceeds 2000 μm, it becomes difficult to stably disperse in the polar solution insoluble in the monomer solution. The yield of bell structure resin particles may be deteriorated.

In the primary emulsification step, the core fine particle dispersion is added to the monomer solution and stirred to emulsify. The emulsification method is not particularly limited, and a conventionally known method can be used.
The size or the like of the hollow portion of the resulting bell structure resin particles corresponds to the size of the droplets composed of the core fine particle dispersion in the emulsion obtained in the primary emulsification step.
In FIG. 1, the schematic diagram which shows the state of the emulsion obtained by the said primary emulsification process was shown. In the emulsified liquid shown in FIG. 1, droplets 1 made of a polar solution insoluble in the monomer solution are dispersed in a medium 2 made of a monomer solution, and further, core particles 3 are dispersed in the droplet 1. .

In the method for producing bell structure resin particles of the present invention, an emulsion (primary emulsion) in which droplets composed of a nuclear fine particle dispersion are dispersed in the monomer solution is added to a polar solution insoluble in the monomer solution and stirred. Thus, an emulsion (a so-called W / O / W type emulsion: hereinafter also referred to as a secondary emulsion) in which droplets composed of a monomer solution containing the nuclear fine particle dispersion are dispersed in a polar solution insoluble in the monomer solution. A secondary emulsification step of preparing a).

The monomer solution used in the secondary emulsification step and the polar solution insoluble can be the same as those used in the primary emulsification step, and may be the same as those used in the primary emulsification step. Also good.
Moreover, it does not specifically limit as said emulsification method, A conventionally well-known method can be used.

In FIG. 2, the schematic diagram which shows the state of the dispersion liquid obtained by the said secondary emulsification process was shown. In the dispersion shown in FIG. 2, droplets 2 made of a monomer solution are dispersed in a medium 4 made of a polar solution that is insoluble in the monomer solution. The droplets 2 made of the monomer solution are polar insoluble in the monomer solution. The solution 1 is encapsulated, and the core particles 3 are dispersed in the polar solution 1 insoluble in the monomer solution.

The method for producing bell-structure resin particles of the present invention includes a polymerization step in which the monomer component is polymerized to obtain resin particles containing the core particle dispersion.
In the polymerization step, the monomer component is polymerized to form the shell portion of the bell structure resin particles. The polymerization method is not particularly limited, and an optimal method may be appropriately selected depending on the types of the monomer component and the polymerization initiator, but heating is usually preferable.

The manufacturing method of the bell structure resin particles of the present invention includes a drying step of removing the polar solution included from the resin particles including the core particle dispersion to obtain the bell structure resin particles.
The removal method is not particularly limited, but vacuum drying or the like is preferable. The polar solution encapsulated in the resin particles by vacuum drying is the gap between the resin shell molecules, and, if the monomer solution contains a non-polymerizable organic solvent, the pores formed by the removal. Transpiration from.
Thereby, bell structure resin particles are obtained.

FIG. 3 shows a cross-sectional view of an example of bell structure resin particles obtained by the method for producing bell structure resin particles of the present invention. In the example shown in FIG. 3A, only one nuclear fine particle exists in the shell made of resin, and in the example shown in FIG. 3B, a plurality of nuclear fine particles exist in the shell made of resin. The bell structure resin particles of any aspect can exhibit excellent vibration damping properties and sound insulation properties.
The type of bell structure resin particles obtained depends on the type of monomer component used, the type and size of the core fine particles, the particle size of the droplets in the primary emulsification step, and the particle size of the droplets in the secondary emulsification step. Can be controlled.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the bell structure resin particle which can manufacture easily the bell structure resin particle in which the core fine particle was included in the void | hole of the shell which consists of resin can be provided.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

Example 1
(1) Preparation of nuclear fine particle dispersion Liquid fine particles of calcium carbonate having a particle diameter of 50 μm are added to ion-exchanged water containing 1% by weight of sodium chloride and 0.02% by weight of sodium nitrite as a water-soluble polymerization inhibitor. It added so that it might become a density | concentration of 10 weight%, and it stirred using the stirring dispersion apparatus, and obtained the nuclear fine particle dispersion.

(2) Preparation of primary emulsion 40 parts by weight of methyl methacrylate as a monofunctional acrylic monomer, 10 parts by weight of trimethylolpropane triacrylate as a polyfunctional acrylic monomer, and azobisisobutyronitrile (AIBN) 0. 25 parts by weight and 2 parts by weight of glycerin monostearate as a lipophilic emulsifier were mixed and stirred to prepare a monomer solution.
50 parts by weight of the core fine particle dispersion was added to the obtained monomer solution, and the mixture was stirred and emulsified using a stirring and dispersing device to obtain a primary dispersion.

(3) Preparation of secondary emulsion The primary dispersion obtained in 300 parts by weight of ion-exchanged water containing 1% by weight of polyvinyl alcohol as a dispersant and 0.02% by weight of sodium nitrite as a water-soluble polymerization inhibitor. 102.25 parts by weight of the liquid was added, the core fine particle dispersion was added, and the mixture was stirred and emulsified using a stirring and dispersing device to obtain a secondary dispersion.

(4) A 20 L polymerization vessel equipped with a polymerization stirrer, jacket, reflux condenser and thermometer was prepared, the inside of the polymerization vessel was depressurized and the inside of the container was deoxygenated, and then the atmosphere was changed to a nitrogen atmosphere. Into this polymerization vessel, 10 L of the obtained secondary dispersion was charged all at once, the temperature of the polymerization vessel was raised to 60 ° C., and polymerization was started. After polymerization for 4 hours, the temperature was further raised to 80 ° C. and the mixture was aged for 1 hour, and then cooled to room temperature.
The obtained slurry was dehydrated by a dehydrator and then vacuum-dried to obtain bell structure resin particles having an average particle diameter of about 200 μm.

(5) Structural evaluation The obtained bell structure particles were embedded in an epoxy resin, and the cut cross section was observed with a scanning electron microscope. As a result, the presence of one or several nuclear fine particles was confirmed inside the particles.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the bell structure resin particle which can manufacture easily the bell structure resin particle in which the core fine particle was included in the void | hole of the shell which consists of resin can be provided.

It is a schematic diagram which shows the state of the emulsion obtained by the primary emulsification process. The schematic diagram which shows the state of the emulsion obtained by the secondary emulsification process. It is sectional drawing of an example of the bell structure resin particle obtained by the manufacturing method of the bell structure resin particle of this invention.

Explanation of symbols

1 Droplet composed of a monomer solution and an insoluble polar solution, or a polar solution insoluble to a monomer solution 2 A medium composed of a monomer solution, or a droplet composed of a monomer solution 3 A core particle 4 A composed of a monomer solution and an insoluble polar solution Medium

Claims (2)

In a monomer solution containing a monomer component and a polymerization initiator, a nuclear fine particle dispersion in which nuclear fine particles are dispersed in a polar solution insoluble in the monomer solution is added and stirred to disperse the nuclear fine particles in the monomer solution. A primary emulsification step for preparing an emulsion in which liquid droplets are dispersed;
A liquid consisting of a monomer solution containing the nuclear fine particle dispersion is added to and stirred in a polar solution that is insoluble in the monomer solution, and an emulsion in which droplets of the nuclear fine particle dispersion are dispersed in the monomer solution. A secondary emulsification step of preparing an emulsion in which droplets are dispersed in a polar solution insoluble in the monomer solution;
A polymerization step of polymerizing the monomer component to obtain resin particles enclosing the nuclear fine particle dispersion;
A method for producing bell structure resin particles, comprising: removing a polar solution contained from the resin particles containing the core fine particle dispersion to obtain bell structure resin particles. The method for producing bell structure resin particles according to claim 1, wherein the monomer solution contains an acrylic monomer as a main component.

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