JP4183603B2 - Method for producing hollow resin particles and hollow resin particles - Google Patents

Description

  The present invention relates to a method for producing hollow resin particles and hollow resin particles, and more specifically, to a method for producing hollow resin particles having no structurally fragile primary particle aggregation portion in the resin skeleton, and the production method. It relates to the hollow resin particles obtained.

  Patent Document 1 below discloses an example of a method for producing hollow polymer particles. Here, first, a non-polymerizable organic solvent is mixed with a mixed monomer composed of a polyfunctional monomer and other monomers to prepare a monomer solution. Next, after suspending the monomer solution in a polar solvent, the monomer component is polymerized to obtain polymer particles containing the non-polymerizable organic solvent. Then, hollow polymer particles are obtained by removing the organic solvent in the polymer particles.

  However, in the above production method, when the monomer solution containing the organic solvent is suspended or emulsified as oil droplets and polymerized, the crosslinking component in the monomer solution is precipitated as the polymerization proceeds. Therefore, primary particles that are finer than the intended particles are easily formed in the oil droplets, and the resin skeleton of the obtained hollow resin particles includes a structurally fragile skeleton portion in which the primary particles are aggregated. Therefore, it has been difficult to achieve high particle strength in high hollowness polymer particles obtained by using a large amount of an organic solvent.

  On the other hand, a hollow (W / O / W) type emulsion in which water droplets (inner aqueous phase) are further encapsulated in oil droplets dispersed in the aqueous phase (outer aqueous phase), which is a continuous phase, is hollowed out. A method for producing resin particles is also known. For example, Patent Document 2 below discloses hollow porous resin particles obtained by such a production method. In such a production method, the hollow portion is formed by the inner aqueous phase, and since the oil phase is entirely a polymerization component, formation of primary particles is not observed during the polymerization. Alternatively, even if primary particles are formed in the polymerization process, the primary particles are taken into the finally obtained skeleton polymer, and hollow resin fine particles having an integrated polymer skeleton are obtained.

  However, in the production method described in Patent Document 2, an oil phase containing a monomer, a nonionic surfactant, and an initiator is dispersed in an aqueous phase containing an ionic surfactant, and (W / O / W) type emulsion was obtained. In this method, it was difficult to control the content (namely, hollowness) of the inner aqueous phase in the (W / O / W) type emulsion. In addition, the hollowness of the obtained hollow resin particles is at most about 42%, and it was difficult to obtain hollow resin particles having a high hollowness.

  On the other hand, in Non-Patent Document 1 below, styrene and divinylbenzene are used as a skeletal material, and a stable (W / O) emulsion is first prepared (primary emulsification), and then further into the outer aqueous phase (W / O) Using a two-stage emulsification process of dispersing the emulsion (secondary emulsification), a (W / O / W) composite emulsion is prepared, and (W / O / W) utilizing in-situ polymerization of the composite emulsion A method for producing such crosslinked hollow microcapsules is disclosed. In such a method using two-stage emulsification, the content (namely, hollowness) of the inner aqueous phase can be controlled by adjusting the volume of water in the first-stage emulsification, and the resulting hollow resin The hollowness of the particles can be increased.

However, Non-Patent Document 1 only describes a method for producing a composite emulsion using styrene and divinylbenzene as a skeleton substance, and does not describe a method for producing hollow resin particles using an acrylic monomer. Absent. This is because it is difficult to obtain a stable (W / O / W) type emulsion when an acrylic monomer having a relatively high hydrophilicity is used as the main component of the oil phase, and (W / O / W) It is considered that the inner aqueous phase is dissipated out of the oil droplets during the production of the composite emulsion or in the subsequent polymerization step, and it is difficult to obtain hollow resin particles having a predetermined hollowness.
JP 2003-10617 A JP 60-184004 A Chemical Engineering Vol. 23, No. 2 (1997)

  An object of the present invention is a method for producing hollow resin particles comprising a resin skeleton having an acrylic resin as a main component and having a single or a plurality of hollow portions therein, wherein there is no skeleton portion in which primary particles are aggregated on the resin skeleton, It is another object of the present invention to provide such hollow resin particles.

  In preparing (W / O / W) type emulsions, a method using a lipophilic emulsifier has been known so far, but a relatively hydrophilic acrylic monomer is used as the main component of the oil phase. The present inventors have found that it is extremely important to strictly control the HLB value of the lipophilic emulsifier in order to obtain a stable (W / O / W) type emulsion. It came to.

Method for producing a hollow resin particles according to the present invention, the aqueous phase is the continuous phase, and the monomer component you containing 50 to 100 wt% of an acrylic monomer, and a lipophilic emulsifier of HLB ≦ 2, and a polymerization initiator A step of preparing a suspension of a composite emulsion in which the oil droplets contained therein are dispersed and a liquid phase in which the monomer component constituting the oil droplet is insoluble is included in the oil droplet; Using a suspension to polymerize the monomer component to obtain resin particles containing a liquid phase; and removing the liquid contained in the resin particles to obtain hollow particles. Features.
Moreover, according to the method for producing hollow resin particles according to the present invention, a monomer component containing 50 to 100% by weight of an acrylic monomer in an aqueous phase that is a continuous phase, a lipophilic emulsifier with HLB ≦ 2, and polymerization initiation And a suspension of a composite emulsion in which a liquid phase containing a water-soluble polymerization inhibitor and insoluble in a monomer component constituting the oil droplet is contained in the oil droplet. A step of preparing a suspension, a step of polymerizing the monomer component using the suspension of the composite emulsion to obtain resin particles in which a liquid phase is included, and a liquid included in the resin particles. And a step of removing the hollow particles to obtain hollow particles. A method for producing hollow resin particles is provided.

  In the above composite emulsion, the liquid phase in which the monomer component is insoluble is mainly composed of water or polyol, but when composed of water, the composite emulsion is (W / O / W) type composite emulsion. It becomes. In the present specification, the liquid phase in which the monomer component is insoluble is not limited to water. However, in the description of the composite emulsion, in order to facilitate the description, the (W / O / W) type composite is used. The term “emulsion” will be described as appropriate.

  In another specific aspect of the method for producing hollow resin particles according to the present invention, polyglycerin polyfatty acid ester is used as the lipophilic emulsifier.

  In still another specific aspect of the method for producing hollow resin particles according to the present invention, the monomer component further includes a polyfunctional monomer other than the acrylic monomer.

  In still another specific aspect of the method for producing hollow resin particles according to the present invention, the oil droplets contain a non-polymerizable organic solvent.

  In a wide aspect of the hollow resin particles according to the present invention, hollow resin particles characterized by having a hollowness of 50% by weight or more are provided.

  In the method for producing hollow resin particles according to the present invention, a monomer component mainly composed of an acrylic monomer, a polymerization initiator, a lipophilic emulsifier with HLB ≦ 5, and an aqueous phase that is a continuous phase, if necessary. Polymerization using a suspension of a composite emulsion in which oil droplets containing an organic solvent contained therein are dispersed and contained in a liquid phase in which the monomer components constituting the oil droplets are insoluble And the inner aqueous phase and the organic solvent are volatilized from the resin particles obtained by polymerization, whereby hollow resin particles are obtained. In the present invention, because the HLB value of the lipophilic emulsifier is in the specific range, a stable (W / O / W) type emulsion can be prepared. It is possible to obtain hollow resin particles that are difficult to break and have a dense internal cell structure and high hollowness.

In the method for producing hollow resin particles according to the present invention, since the HLB value of the lipophilic emulsifier is 2 or less , the effect of stabilizing the (W / O / W) type emulsion is further enhanced.

  Moreover, when a polyglycerin polyfatty acid ester is used as the lipophilic emulsifier, the emulsion stabilization effect is further enhanced.

Further, in the liquid phase the monomer component is insoluble, in the case where water soluble polymerization inhibitor is contained, in the liquid phase in the monomer component is insoluble, in a case where slight exists monomer components However, the polymerization in the liquid phase in which the monomer component is insoluble is reliably suppressed. Therefore, generation of fine primary particles can be more effectively suppressed.

  In the production method according to the present invention, the monomer component contains an acrylic monomer as a main component, but may further contain a polyfunctional monomer. The polyfunctional monomer forms various bonds during the polymerization reaction and acts to increase the strength of the obtained resin particles. Therefore, the compression strength of the hollow resin particles obtained by blending the polyfunctional monomer can be increased.

  In the hollow resin particles obtained by the present invention, there are almost no fragile skeleton portions in which primary particles are aggregated in the resin skeleton portions. Or significantly less. Therefore, the strength of the hollow resin particles can be effectively increased.

  In the production method according to the present invention, since a stable (W / O / W) type composite emulsion is obtained, the weight fraction of the liquid phase in which the monomer component constituting the oil droplet contained in the oil droplet is insoluble is determined. As a result, it is possible to easily obtain hollow resin particles having a hollowness of 50% by weight or more. Further, in the obtained hollow resin particles, there are almost no fragile skeleton portions in which primary particles are aggregated in the resin skeleton portions. Or since it is remarkably few, it is high hollowness and high intensity | strength.

  In the method for producing hollow resin particles according to the present invention, first, a suspension of the composite emulsion is prepared. In preparing the suspension of the composite emulsion, first, the components constituting the oil droplets of the composite emulsion are prepared. That is, a monomer component, a polymerization initiator, an oil-soluble emulsifier with HLB ≦ 5, that is, a (W / O) type emulsifier, and an organic solvent contained as necessary are mixed to obtain a monomer solution.

  Thereafter, the monomer solution and the liquid in which the monomer component is insoluble are stirred to obtain a fine (W / O) type emulsion having a desired size.

  Next, the obtained (W / O) type emulsion is further added to a solution containing a dispersant and a water-soluble polymerization inhibitor added as necessary, and stirred to obtain a large number of fine particles in the oil droplets. (W / O / W) type composite emulsion suspension containing a liquid in which a monomer component is insoluble is prepared.

  Then, the monomer component is polymerized using the suspension of the composite emulsion, and the hollow resin particles are obtained by removing the inner aqueous phase and the organic solvent in the obtained resin particles.

  The polymerization method is not particularly limited, and the suspension polymerization method is preferably used because it is easy to control the particle diameter and easily form an effective hollow portion.

  The monomer component constitutes the resin skeleton of the hollow resin particles by polymerization. As such a monomer component, a monomer component having an acrylic monomer as a main component is used, and preferably the above-mentioned polyfunctional monomer is further included.

  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- And hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-acryloyloxyethylphthalic acid, itaconic acid, fumaric acid, dimethylaminomethyl methacrylate, etc. Details, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and (meth) acrylic acid.

  The acrylic monomer may be a polyfunctional monomer. In that case, the compressive strength of the hollow particles can be increased. As the acrylic polyfunctional monomer, di (meth) acrylate, tri (meth) acrylate and the like are preferably used. Examples of the di (meth) acrylate include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and trimethylolpropane. Examples include di (meth) acrylate. Examples of the tri (meth) acrylate include trimethylolpropane tri (meth) acrylate, ethylene oxide-modified trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, and the like. These can be used alone or in combination of two or more.

  The amount of the acrylic monomer used is not particularly limited. However, when it is used in cosmetics, ceramic pore-forming agents, and the like, if it is too small, the water absorption may be lowered. Therefore, 50 to 99.9 in the monomer component. It is preferably used in an amount of% by weight, more preferably 70 to 99.9% by weight.

In the present invention, a polyfunctional monomer other than the acrylic monomer may be further added to increase the compressive strength of the hollow particles. Examples of polyfunctional monomers other than acrylic monomers include pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, diallyl phthalate, diallyl malate, diallyl fumarate, diallyl succinate, triallyl isocyanate, and the like. And divinyl compounds such as di- or triallyl compounds, divinylbenzene, and butadiene.

  These polyfunctional monomers can be used alone or in combination of two or more.

  If the amount of the polyfunctional monomer used is too small, the compression resistance of the hollow resin particles may not be sufficient. Therefore, the acrylic polyfunctional monomer and / or the polyfunctional monomer other than the acrylic monomer in all the monomer components. Is preferably 0.1 to 100% by weight, more preferably 0.3 to 100% by weight.

  In the present invention, other monomers may be used in addition to the acrylic monomer and polyfunctional monomer. Such other monomers are added for the purpose of improving mechanical strength, chemical resistance and moldability, and the type is not particularly limited, but examples thereof include styrene, α-methylstyrene, p-methylstyrene, p-chloro. Examples thereof include aromatic vinyl monomers such as styrene; vinyl esters such as vinyl acetate and vinyl propionate; halogen-containing monomers such as vinyl chloride and vinylidene chloride; ethyl, propylene, butadiene and the like. These can be used alone or in combination of two or more.

  In the present invention, as the organic solvent contained in the oil droplets as necessary, any appropriate organic solvent can be used as long as it is a non-polymerizable organic solvent. As the organic solvent, for example, butane, pentane, hexane, heptane, cyclohexane, toluene, xylene, ethyl acetate, methyl chloride, methylene chloride, chloroform, carbon tetrachloride and the like are preferably used. Among these, highly volatile butane, pentane, hexane, cyclohexane, and ethyl acetate are more preferable.

  If the amount of the organic solvent added is too small, the hollowness of the particles may not be sufficiently high, and if too large, the hollowness may be too high and the strength of the particles may be reduced. The amount is preferably 0 to 400 parts by weight, more preferably 0 to 100 parts by weight with respect to parts by weight.

  In addition, by making the addition amount of the organic solvent relatively large, as will be apparent from Examples described later, porous hollow resin particles can be obtained.

  Examples of the lipophilic emulsifier having HLB ≦ 5 include glycerin monopalmitate (4.3), glycerin monostearate (4.3), glycerin monobehenate (4.2), glycerin monooleate ( 4.3) monoglycerol fatty acid ester, glycerol dipalmitate (3.2), glycerol distearate (3.2), glycerol tristearate (1.7), glycerol dibehenate (2.8) , Monoglycerin polyfatty acid esters such as glycerindiolate (3.1), polyglycerin polyfatty acid esters such as polyglycerin polyricinoleate (0.3), sorbitan monopalmitate (4.8), sorbitan monostearate ( 5.0), sorbitan fatty acid esters such as sorbitan monooleate (4.6), sol Examples include sorbitan polyfatty acid esters such as tan tristearate (2.0), sorbitan tribehenate (1.5), sorbitan trioleate (3.0) (the values in parentheses are HLB values, and RIKEN According to the catalog of Vitamin Co., Ltd. Moreover, the HLB value of monoglycerin polyfatty acid ester shows the numerical value of a mixture with monoglycerin fatty acid ester.)

Among the lipophilic emulsifiers having HLB ≦ 5, the use of the lipophilic emulsifier having HLB ≦ 2 is more preferable for stabilizing the (W / O / W) type composite emulsion. For example, glycerin tristearate (HLB value) = 1.7), polyglycerin polyricinoleate (HLB value = 0.3), sorbitan tristearate (HLB value = 2.0), sorbitan tribehenate (HLB value = 1.5) and the like. . More preferably, polyglycerin polyricinoleate (HLB value = 0.3) having an extremely small HLB value is used.

  The amount of the emulsifier used is preferably 0.01 to 50% by weight, more preferably 0.1 to 20% by weight, based on the total weight of the monomer components, as the concentration of the emulsifier in the monomer solution. is there. If it is less than 0.1% by weight, it may be difficult to form a (W / O) type emulsion. If it exceeds 20% by weight, a large number of emulsifiers are mixed inside the polymer skeleton, and the strength of the resulting hollow particles May be low.

  The polymerization initiator added to the oil droplets is not particularly limited, for example, organic peroxides such as benzoyl peroxide, lauroyl peroxide, dibutyl peroxydicarbonate, α-cumyl peroxyneodecanoate, Examples include azo-based initiators such as azobisisobutyronitrile, redox initiators, and the like.

  In addition, although it does not specifically limit as a liquid which comprises the liquid phase in which the said monomer component is insoluble, Polyols, such as water and glycerol, are used preferably. More preferably, the liquid phase in which the monomer component is insoluble contains a water-soluble polymerization inhibitor as described above. By including the water-soluble polymerization inhibitor, polymerization of the monomer component in the liquid phase is surely suppressed even when the monomer component is slightly present in the liquid phase in which the monomer component is insoluble. Examples of such water-soluble polymerization inhibitors include sodium nitrite, copper chloride, iron chloride, titanium chloride, hydroquinone and the like.

  Moreover, you may add dispersing agents, such as polyvinyl alcohol, and various salts, such as sodium chloride, to a water-soluble polymerization inhibitor and a soot. By adding the dispersant, the liquid phase in which the monomer component is insoluble can be sufficiently dispersed and effectively contained in the oil droplets. Further, the addition of salts can effectively suppress the dissolution of the monomer component in the liquid phase, and at the same time, the holding power of the inner aqueous phase in the oil droplets can be increased by adjusting the osmotic pressure of the inner aqueous phase.

  In the production method according to the present invention, a suspension of a composite emulsion is obtained using each of the components described above and according to the method described above, and resin particles are formed by polymerizing monomer components using the composite emulsion. The The obtained resin particles contain an inner aqueous phase and an organic solvent inside. Therefore, by drying, the inner aqueous phase and the organic solvent can be volatilized and the hollow portion can be formed. For drying, an appropriate drying method such as vacuum drying is used.

  The hollow resin particles according to the present invention can be obtained by the above-described production method, but may be obtained by other production methods, and are composed of a resin skeleton having a single or a plurality of hollow portions inside, and the hollow resin particles In the resin skeleton constituting the skeleton, there is no skeleton portion in which primary particles are aggregated, and the hollowness is 50% by weight or more.

  Moreover, the porous hollow resin particle which concerns on this invention is obtained according to the said manufacturing method by increasing the quantity of the organic solvent used as mentioned above. In the porous hollow resin particles, the hollow portion formed near the surface has a relatively large number of minute hollow portions smaller than the voids of the hollow portion formed inside.

  Next, the present invention will be described in more detail by giving specific examples. In addition, this invention is not limited to a following example.

( Reference Example 1)
Using the composition shown in Table 1 below, porous hollow resin particles were obtained in the following manner.

  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 0.25 weight of azobisisobutyronitrile (AIBN) as a polymerization initiator Parts and 2 parts by weight of glycerin monostearate as a lipophilic emulsifier were mixed and stirred to prepare a monomer solution.

  Next, sodium chloride is added to ion exchange water to a concentration of 1% by weight, and an aqueous solution in which sodium nitrite as a water-soluble polymerization inhibitor is added to a concentration of 0.02% by weight is added. Produced. The monomer solution (52.25 parts by weight) and the sodium chloride / sodium nitrite aqueous solution (50 parts by weight) were stirred using a stirring and dispersing device to form a (W / O) type emulsion.

  Thereafter, polyvinyl alcohol (PVA) as a dispersant is added to the dispersion in which the (W / O) type emulsion is dispersed so as to have a concentration of 1% by weight as a water-soluble polymerization inhibitor. 300 parts by weight of an aqueous solution to which sodium nitrite is added to a concentration of 0.02% by weight is added and stirred by a stirring and dispersing device to enclose a number of fine water droplets in the oil droplets (W / O / W) type composite emulsion suspension was obtained.

  A 20 liter polymerization vessel equipped with a stirrer, a jacket, a reflux condenser and a thermometer was prepared, and the inside of the polymerization vessel was depressurized to deoxygenate the vessel. Thereafter, the pressure is returned to atmospheric pressure with nitrogen gas, and the inside of the polymerization vessel is set to a nitrogen atmosphere, and then (W / O / W) type composite emulsion suspension is charged in a lump, and the polymerization vessel is heated to 60 ° C. The polymerization was started. After polymerization for 4 hours, the temperature was further raised to 80 ° C. and aging was performed for 1 hour, and then the polymerization vessel was cooled to room temperature. The slurry thus obtained was dehydrated with a dehydrator and then vacuum dried to obtain porous hollow resin particles.

(Examples 1 to 3 , Comparative Example 1)
Except that the used material was changed as shown in Table 1, porous hollow resin particles were obtained in the same manner as in Reference Example 1.

(Comparative Example 2)
As shown in Table 1 below, 40 parts by weight of methyl methacrylate as a monofunctional monomer, 10 parts by weight of trimethylolpropane triacrylate (TMP) as a polyfunctional monomer, 50 parts by weight of cyclohexane as an organic solvent, and a polymerization initiator A monomer solution was prepared by mixing and stirring 0.25 parts by weight of AIBN.

  Next, polyvinyl alcohol (PVA) as a dispersant is added to the monomer solution so as to have a concentration of 1% by weight, and sodium nitrite as a water-soluble polymerization inhibitor has a concentration of 0.02% by weight. 300 parts by weight of the aqueous solution added so as to become was added and stirred by a stirring and dispersing device to obtain a suspension.

  The suspension was put into a 20 liter polymerization vessel equipped with a stirrer, a jacket, a reflux condenser, and a thermometer, and stirred. Thereafter, the inside of the polymerization vessel was depressurized and deoxygenated, then the pressure was returned to atmospheric pressure with nitrogen, and the interior was made a nitrogen atmosphere. Thereafter, the temperature of the polymerization vessel was raised to 60 ° C., and polymerization was started. The polymerization was completed in 4 hours, further heated at 80 ° C. and aged for 1 hour, and the polymerization vessel was cooled to room temperature. The slurry thus obtained was dehydrated with a dehydrator and then vacuum dried to remove the organic solvent and obtain hollow resin particles.

(Comparative Example 3)
As shown in Table 1, thermally expandable microcapsules F-85D manufactured by Matsumoto Yushi Seiyaku Co., Ltd. were heated at 170 ° C. for 1 minute to produce hollow polymer particles, which were evaluated as resin particles of Comparative Example 3.

(Evaluation of Reference Examples, Examples and Comparative Examples)
About the hollow resin particles obtained as described above, (1) the appearance is visually observed, (2) the morphology inside the particles is confirmed by cutting the particles and observing the cross section, and (3) average particles The diameter, (4) hollowness, and (5) strength were evaluated as follows.

  [Average Particle Size] The volume average particle size was measured with a laser diffraction particle size distribution analyzer LA-910 manufactured by HORIBA, Ltd. Three places were sampled from any place of the powder, and the average value was used.

[Hollowness] Measured with a Porosimeter 2000 manufactured by AMCO. The enclosed mercury pressure was 2000 kg / cm ² . Samples 0.5 sampled from any location were used for evaluation.

  [Strength Evaluation] 2 g of each particle and 200 g of sphere beads made of zirconia having a diameter of 5 mm were set on a ball mill and stirred for 10 minutes at a rotation speed of 500 times per minute. Thereafter, the degree of crushing of the taken out particles was judged using the following criteria using an optical microscope.

A: Almost not crushed B: Slightly crushed Δ: Many crushed X: Almost crushed

MMA: methyl methacrylate, TMP: trimethylolpropane triacrylate, AIBN: azobisisobutyronitrile, PVA water: polyvinyl alcohol aqueous solution (10% by weight partially saponified polyvinyl acetate aqueous solution)
Moreover, in the resin particle | grains marked with * in Table 1, it means that a big hole exists in the center part and a minute hole exists near the surface.

Claims (7)

The aqueous phase is the continuous phase, and the monomer component you containing 50 to 100 wt% of an acrylic monomer, and a lipophilic emulsifier of HLB ≦ 2, the oil droplets containing a polymerization initiator are dispersed, oil droplets A step of preparing a suspension of a composite emulsion in which a liquid phase in which the monomer component constituting the oil droplet is insoluble is included;
Using the suspension of the composite emulsion to polymerize the monomer component to obtain resin particles containing a liquid phase;
Removing the liquid contained in the resin particles to obtain hollow particles, and a method for producing hollow resin particles. Oil droplets containing a monomer component containing 50 to 100% by weight of an acrylic monomer, a lipophilic emulsifier with HLB ≦ 2, and a polymerization initiator are dispersed in an aqueous phase that is a continuous phase. A step of preparing a suspension of a composite emulsion containing a liquid phase containing a water-soluble polymerization inhibitor and insoluble in a monomer component constituting an oil droplet;
Using the suspension of the composite emulsion to polymerize the monomer component to obtain resin particles containing a liquid phase;
Removing the liquid contained in the resin particles to obtain hollow particles, and a method for producing hollow resin particles. As a lipophilic emulsifier, method for producing hollow particles according to claim 1 or 2, characterized by using the polyglycerol fatty acid ester. The method for producing hollow resin particles according to any one of claims 1 to 3 , wherein a polyfunctional monomer is further contained as the monomer component. The oil in includes a non-polymerizable organic solvent, the production method of the hollow resin particles according to any one of claims 1-4. Hollow resin particles obtained by the production method according to claim 1-5. Obtained by the production method according to claim 1-5, hollow resin particles hollow degree of 50 wt% or more.