JP3165469B2 - Method for producing polymer particles having inner pores - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Industrial application] Organic pigments are superior to inorganic pigments in terms of lightness and thermoplasticity.
Used in fields such as paint and coated paper. In recent years, polymer particles having an inner hole have been produced for the purpose of improving the lightness and opacity of an organic pigment. The present invention relates to a polymer particle having such an inner hole.

[0002]

2. Description of the Related Art Processes for producing polymer particles having an inner pore have been known for a long time. For example, Japanese Patent Publication Nos. 36-9168 and 37-14327 disclose that the solvent is contained in the inner hole by carrying out suspension polymerization or emulsion polymerization in the presence of a water-insoluble non-polymerizable organic solvent. It is disclosed that the resulting polymer particles are obtained. However, such a method has disadvantages such as that particles having inner pores cannot be obtained satisfactorily and that the particle diameter and the distribution of inner pore diameter become extremely large. When using such a method,
JP-A-61-66710 and JP-A-62-127336.
The publication also describes that it can be carried out in the presence of polymer particles as seed particles. However, also in the case of using seed particles, it is difficult to stably obtain polymer particles having inner pores, and it is difficult to control the particle diameter and inner pore diameter with respect to the method of using a non-polymerizable organic solvent. It is difficult to obtain a polymer particle having an inner hole having excellent strength, and there is a problem that the inner hole shrinks when a solvent contained in the particle is removed. .

Japanese Patent Application Laid-Open No. 63-135409 also discloses a method in which the core of core / shell type polymer particles is preferentially swelled with an organic solvent compatible with the polymer to develop inner pores when dried. Has been stated. However, in this method, the core / shell type polymer particles to be used need to be designed to have a solvent swelling property because they need to absorb only an organic solvent and swell. It is difficult to obtain polymer particles having pores, it is difficult to remove the solvent compatible with the polymer, and the polymer in the shell part is plasticized to some extent by the organic solvent used. However, when the solvent is removed or dried, the whole particles shrink and the inner pores are reduced and disappear.

On the other hand, several methods for producing polymer particles containing inner pores without using such an organic solvent are also known. For example, a basic substance is applied to polymer particles comprising an alkali-swellable core portion and a shell portion covering the core portion as disclosed in JP-A-56-32513 to cause the core portion to swell and expand, thereby forming an inner hole during drying. Japanese Patent Application Laid-Open No. 2-173101 discloses a method for obtaining particles expressing
In the above-mentioned publication, there is a method of hydrolyzing the core of a core / shell type polymer in which the core comprises a vinyl acetate polymer.
However, in these methods, since the shell portion needs to have plasticity in order for the core portion to expand, it is difficult to obtain a polymer particle having an inner hole excellent in strength, However, the water absorbed by the polymer is difficult to remove, so that there is a problem that the drying property when used for a predetermined application is poor.

Japanese Patent Application Laid-Open No. 61-62510 also discloses a method of polymerizing a monomer having a solubility parameter different from that of the seed particle by 0.1 or more. There was a problem that the inner hole diameter could not be obtained.

[0006]

As described above, the problem to be solved by the present invention is that, while easily controlling the particle diameter and the inner hole diameter, an inner hole larger than the particle diameter can be obtained, and When removing the inner hole does not shrink,
It also means that there has been no satisfactory method for obtaining polymer particles having inner pores excellent in strength.

[0007]

In order to solve the above-mentioned problems, the present inventors have intensively studied a method for producing polymer particles having an inner hole which can sufficiently satisfy these various problems. As a result, the present invention has been completed. That is, the present invention relates to a method for producing a polymer having an inner hole, which comprises the following (Step 1) and (Step 1)
The particulate polymer (b) obtained in 2) is converted to a particulate polymer
A polymer having 1 to 10 parts by weight of a polymerizable vinyl monomer (B) and a polymer having the above-described inner pores alone in a dispersion medium containing 100 parts by weight of a particulate polymer (A) used as (A). Non-polymerizable organic solvent (C) that is substantially incompatible with the particles
A process for producing polymer particles having an inner pore, characterized by adding 1 to 100 parts by weight and polymerizing. (Process
1) The melt viscosity at 120 ° C. is 10 ⁵ Pa · S (pass
Water having a particle size of 0.1 to 2μ or less
A step of polymerizing the dispersible particulate polymer (a). (Step 2)
Using the particulate polymer (a) as seed particles,
Is obtained by adding monomers of different composition to the dispersion medium and polymerizing.
Is 0.2 to 5 μm and the melt viscosity at 150 ° C.
Water-dispersible particulate polymer having a degree of 10 ⁴ Pa · S or more
(B) a step of obtaining;

[0008] The particulate polymer (A) in the present invention is:
Usually, aromatic vinyl compounds such as styrene, α-methylstyrene and p-methylstyrene, and conjugated diolefins such as butadiene, and chlorine-containing vinyl compounds such as vinyl chloride and vinylidene chloride, and acetic acid such as vinyl acetate Esters and unsaturated nitrile compounds such as acrylonitrile and methacrylonitrile, and methacrylic acid such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, and allyl methacrylate Esters, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, 2-hydro Acrylic esters such as silethyl acrylate, glycidyl acrylate, allyl acrylate, and unsaturated acids such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, and unsaturated amides such as acrylamide, methacrylamide, and Divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate,
1.3-butanediol dimethacrylate, 1,3-butanediol diacrylate, 1,4-butanediol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol dimethacrylate,
Particles which are polymerized by emulsion polymerization or suspension polymerization using monomers such as crosslinkable monomers such as 1,6-hexanediol diacrylate and triallyl isocyanurate. It is also possible to use another polymer polymerized by another method in the form of particles. When polymerizing these monomers, if necessary, mercaptans such as t-dodecyl mercaptan and octyl mercaptan, or halides such as carbon tetrachloride and ethylene bromide, or ethylhexyl thioglycolate and α- A chain transfer agent such as methylstyrene dimer is used. The shape of the particles is usually spherical, but other shapes can also be used. The size of the particles is not particularly limited as long as the particles can be dispersed in the dispersion medium, but when used for paints and coated papers, the diameter is preferably about 0.2 to 5 μm, more preferably 0.1 to 5 μm. 3 to 2μ. The structure of the particles may be homogeneous or heterogeneous, but is preferably a particulate polymer (b) obtained by the following (Step 1) and (Step 2). (Step 1) A step of polymerizing a water-dispersible particulate polymer (a) having a melt viscosity at 120 ° C. of 10 ⁵ Pa · S (pascal-second) or less and a particle diameter of 0.1 to 2 μm. (Step 2) Using the particulate polymer (a) as seed particles, a monomer having a composition different from that used in the polymerization of the seed particles is added to a dispersion medium and polymerized to have a particle diameter of 0.2 to 5 μm. Melt viscosity at 150 ° C. is 10 ⁴
A step of obtaining a water-dispersible particulate polymer (b) having a Pa · S or more The particulate polymer (a) obtained in the step (1) is
Polymer particles obtained by generally known methods such as emulsion polymerization and suspension polymerization using the above-exemplified monomers and, if necessary, a chain transfer agent. Particulate polymer (a)
Has a particle size of 0.1 to 2 μm, and the particle size distribution is preferably small. The melt viscosity of the particulate polymer (a) at 120 ° C is 10 ⁵ Pa · S or less, and its glass transition temperature is preferably 110 ° C or less. Further, the particulate polymer (a) is preferably substantially non-crosslinked. The particulate polymer (b) obtained in the step (2) is different from the monomer composition constituting the particulate polymer (a) in that the particulate polymer (a) is used as seed particles in a dispersion medium. It is a polymer particle obtained by polymerizing a monomer having a composition by a generally known method such as emulsion polymerization or suspension polymerization. Examples of the type of monomer to be used include those exemplified above, and examples of the chain transfer agent include those exemplified above as necessary. The particle diameter of the particulate polymer (b) is 0.2 to 5 μm.
It is preferable that the particle size distribution is small. The weight fraction of the particulate polymer (A) in the particulate polymer (B) is not particularly limited, but is preferably 5 to 70%, and more preferably 10 to 50%. The melt viscosity of the particulate polymer (b) is 10 ^{4 at} 150 ° C.
Pa · S or more. Here, a particulate polymer (b) obtained by using the particulate polymer (a) as a seed particle and polymerizing a monomer having a composition different from that of the particulate polymer (a) is generally a uniform polymer. It is not a particle but a different layer structure type polymer particle, but among such different layer structure type polymer particles, a polymer obtained by polymerizing a particulate polymer (a) as a core and subsequently polymerizing the same is used. It is preferably a core / shell type polymer particle that covers the periphery. When the glass transition temperature of such a particulate polymer (b) is measured, usually, two glass transition temperatures of the one caused by the particulate polymer (a) and the one caused by the polymer polymerized later are obtained. As observed, the glass transition temperature due to the polymer polymerized later is preferably 80 ° C. or higher, more preferably 100 ° C. or higher. The polymer polymerized later does not need to be a crosslinked structure, but is preferably a crosslinked structure. Introducing another polymer so as to further cover the outside of the particulate polymer (b) does not matter at all. In this case, the polymer does not necessarily have to completely cover the surface of the particulate polymer (b), and may exist in an island shape on the surface of the particulate polymer (b). The particle size of the polymer particles can be measured by, for example, observation with an electron microscope. The melt viscosity of the polymer is 0.5 mm in diameter and 1 m in length, for example, using a flow tester CFT-500 manufactured by Shimadzu Corporation.
m nozzle, load 100 kgf, heating rate 3 ° C /
It can be measured under the condition of minutes. The glass transition temperature can be measured using, for example, a viscoelasticity measuring device or a differential thermal analyzer.

The polymerizable vinyl monomer (B) in the present invention
Is not particularly limited as long as it is capable of radical polymerization, and examples thereof include styrene, α-methylstyrene, aromatic vinyl compounds such as p-methylstyrene, conjugated diolefins such as butadiene, and vinyl chloride. Chlorine-containing vinyl compounds such as vinylidene chloride, and acetates such as vinyl acetate; and unsaturated nitrile compounds such as acrylonitrile and methacrylonitrile; and methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, and 2-ethylhexyl methacrylate. , Methacrylates such as 2-hydroxyethyl methacrylate, and methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, 2-hydr Acrylic acid esters are mentioned, such as carboxyethyl acrylate, these things are used in combination with one type, or two or more kinds. When polymerizing these monomers, if necessary, mercaptans such as t-dodecyl mercaptan and octyl mercaptan, or halides such as carbon tetrachloride and ethylene bromide, or ethylhexyl thioglycolate and α- A chain transfer agent such as methylstyrene dimer is used. The polymerizable vinyl monomer (B) preferably has excellent compatibility with the particulate polymer (A) used,
When an aqueous dispersion medium is used, it is preferably hydrophobic, and specifically, the solubility in water is preferably 0.5% by weight or less. The polymerizable vinyl monomer (B) used in 100 parts by weight of the particulate polymer (A) is required to be 1 to 10 parts by weight, but preferably 5 to 10 parts by weight. If the amount of the polymerizable vinyl monomer (B) is less than 1 part by weight, it is difficult to obtain polymer particles having an inner hole. If the amount is more than 10 parts by weight, it becomes difficult to control the particle size of the polymer particles having an inner hole. In addition, when they are added in a lump, it is difficult to control a microscopic temperature rise due to heat of polymerization, and it is difficult to obtain polymer particles having an inner hole.

The non-polymerizable organic solvent (C) in the present invention is not particularly limited as long as it does not have radical polymerizability and is not substantially compatible with polymer particles having an inner hole by itself. This “is substantially insoluble in polymer particles having an inner hole by itself” means that the phenomenon occurs when the unpolymerized polymerizable vinyl monomer (B) is present together with the particulate polymer. Compatible, but with the progress of polymerization of the polymerizable vinyl monomer (B), it becomes incompatible with the particulate polymer,
This means that almost all of the phase is separated from the polymer particles.
Under the conditions of the present invention, the non-polymerizable organic solvent (C) used is considered to form a pore by phase separation inside the polymer particles. In order to be substantially incompatible with the polymer particles having inner pores, it is preferable that the particles are not compatible or very small with the particulate polymer (A) used. The kind of such non-polymerizable organic solvent (C) is
The composition and molecular weight of the particulate polymer (A) used, the type and amount of the polymerizable vinyl monomer (B), and the composition and molecular weight of the polymer particles having an inner pore are affected. And aliphatic hydrocarbons such as pentane, hexane, heptane, octane and isooctane, and alicyclic hydrocarbons such as cyclohexane. Linear aliphatic hydrocarbons having a small solubility parameter are preferred. These are used alone or in combination of two or more. The non-polymerizable organic solvent (C) is used in an amount of 1 to 100 parts by weight, preferably 5 to 80 parts by weight, based on 100 parts by weight of the particulate polymer (A).
Parts by weight, more preferably 10 to 50 parts by weight. If the amount of the non-polymerizable organic solvent (C) used is 1 part by weight or less, the size of the inner hole is too small, and if it is 100 parts by weight or more, it is difficult to obtain polymer particles having an appropriate size of the inner hole.

Next, the manufacturing method of the present invention will be described.
The production of the polymer particles having inner pores according to the present invention can be carried out by a generally known emulsion polymerization or suspension polymerization method. That is, a dispersion medium, a particulate polymer (A), and, if necessary, a surfactant and a dispersion stabilizer are added to a container equipped with a stirrer, a thermometer, and the like, and the polymerizable vinyl monomer is added thereto. In this method, polymerization is performed by adding (B), a non-polymerizable organic solvent (C), a polymerization initiator, and the like. The polymerizable vinyl monomer (B), the non-polymerizable organic solvent (C), the polymerization initiator, and the like may be added all at once, may be added continuously, or may be partially added. May be added all at once and the remaining amount may be added continuously. In the case of continuous addition, the rate of addition may be changed halfway. As a preferred example of the production method,
When a water-soluble polymerization initiator is used, a dispersion medium such as water, a particulate polymer (A), and, if necessary, a surfactant and a dispersion stabilizer are placed in a container equipped with a stirrer, a thermometer, and the like. , A polymerizable vinyl monomer (B) and a non-polymerizable organic solvent (C) are added thereto, and after stirring at a predetermined temperature for a predetermined time, a polymerization initiator is added. And stirring is continued for a predetermined time to complete the polymerization. When an oil-soluble polymerization initiator is used, the initiator is previously dissolved in the polymerizable vinyl monomer (B) or the non-polymerizable organic solvent (C) or a mixture thereof, and these are added to the initial charge. After stirring for a predetermined time at a temperature at which the initiator does not substantially act, raise the temperature above the temperature at which the initiator operates or add a reducing agent, and continue stirring for a predetermined time to complete the polymerization. Can be taken. The polymerizable vinyl monomer (B) and the non-polymerizable organic solvent (C) may be added to the initial charge as they are, but it is preferable to add those which are finely dispersed in a dispersion medium in advance.
Alternatively, it is preferable to add it as it is to the initial charge, and finely disperse it in the system by the action of a surfactant or mechanical stirring. Examples of the method of previously finely dispersing the polymerizable vinyl monomer (B) and the non-polymerizable organic solvent (C) in a dispersion medium include a mechanical disperser such as a homomixer and a biomixer, or an ultrasonic homogenizer. There is a method used, but when finely dispersing, it is usually performed using one or a combination of two or more of the surfactants exemplified below as necessary. If necessary, a poorly water-soluble substance such as dodecyl chloride can also be used. The amount of the surfactant used for fine dispersion is usually 0.1% to 10% as an active ingredient based on the weight of the polymerizable vinyl monomer (B) and the non-polymerizable organic solvent (C). The degree of fine dispersion is usually about 10 μm or less as the particle size of the oil droplet, but the smaller the particle size of the oil droplet, the more preferable. Further, in the production method of the present invention, it is preferable to start polymerization after the added polymerizable vinyl monomer (B) and non-polymerizable organic solvent (C) are sufficiently absorbed by the particulate polymer (A). . The polymerization is started after the added polymerizable vinyl monomer (B) and non-polymerizable organic solvent (C) are sufficiently absorbed by the particulate polymer (A), whereby the used particulate polymer (A) It is easy to control the particle size because the generation of new particles due to polymerization occurring in places other than the above is easy, and the size of the inner pores formed in the particles depends on the amount of the non-polymerizable organic solvent (C) used. Can be controlled more easily. The time required for the added polymerizable vinyl monomer (B) and non-polymerizable organic solvent (C) to be sufficiently absorbed by the particulate polymer (A) depends on the composition of the particulate polymer (A) used, Although it depends on the molecular weight, the type and amount of the polymerizable vinyl monomer (B) and the non-polymerizable organic solvent (C), and the temperature of the system, it is usually within 12 hours. The time required to complete the polymerization after the action of the polymerization initiator varies depending on the type and amount of the initiator and the temperature of the system, but is usually within 5 hours. The temperature setting of the reaction system in the method of the present invention varies depending on the composition and molecular weight of the particulate polymer (A) to be used, the type and amount of the initiator, and the like.
C. to 120.degree.

The surfactants used as required include anionic, cationic, nonionic, amphoteric, and reactive surfactants, and oligosoaps. One of these surfactants may be used. Alternatively, two or more types may be used in combination. Examples of the anionic surfactant include an alkali metal salt of alkyl benzene sulfonic acid, an alkali metal salt of alkyl sulfate, an alkali metal salt of polyoxyethylene alkylphenol sulfate, an alkali metal salt of alkyl diphenyl ether disulfonate, and an alkali metal salt of dialkyl sulfosuccinic acid. it can. As the nonionic surfactant, for example, polyoxyethylene alkylphenol ether, polyoxyethylene alkyl ether, polyoxyethylene higher fatty acid ester, ethylene oxide-propylene oxide block copolymer and the like can be used.

As the dispersion stabilizer, a polymer compound having a function as a protective colloid, such as polyvinyl alcohol, hydroxyethylcellulose and hydroxypropylcellulose, can be used. As the polymerization initiator, a compound that generates a radical at a predetermined temperature is used. Examples of the water-soluble initiator include persulfates such as sodium persulfate, potassium persulfate and ammonium persulfate, and peroxides such as hydrogen peroxide. Examples of the oil-soluble initiator include benzoyl peroxide And organic peroxides such as cumene hydroperoxide, lauroyl peroxide, tert-butyl peroxide and tert-butylperoxy-2-ethylhexanoate, and azo compounds such as azobisisobutyronitrile. These can also be used as a so-called redox initiator in combination with a reducing agent.

It is to be noted that various additives may be used during or after the polymerization. Such additives include pH adjusters, antioxidants, antioxidants, preservatives and the like. When the polymerization is substantially completed, the used non-polymerizable organic solvent (C) is present in the inner pores of the polymer particles having the inner pores. Then, steam or a gas such as nitrogen or air can be blown into the obtained dispersion of polymer particles having inner pores to remove them.

Furthermore, the polymer particles having inner pores obtained by the production method of the present invention can be dried and used as a powder.

[0016]

The present invention will be specifically described below with reference to examples. The parts and percentages in the examples are on a weight basis unless otherwise specified. The reaction was performed under a nitrogen atmosphere.

[0017]

[0018]

Example 2 3.7 parts of seed particles having a particle diameter of 0.1 μm and 100 parts of ion-exchanged water were placed in a flask equipped with a stirrer, a reflux condenser, and a thermometer. Heated and stirred until it was. A mixture of 90 parts of styrene, 10 parts of butyl acrylate (BA), 3 parts of t-dodecyl mercaptan and 0.8 parts of sodium persulfate were added to ion-exchanged water 2
The components dissolved in 0 parts were added over 4 hours, and the mixture was further stirred at 80 ° C. for 2 hours and cooled. The obtained particulate polymer is referred to as a particulate polymer (a).
The solid concentration of the obtained particulate polymer (a) dispersion was 4%.
7.2%, and the particle diameter of the particulate polymer (a) was 0.3 µ as observed with an electron microscope. The obtained dispersion was dried to obtain a powder of the particulate polymer (a). Using a flow tester, a nozzle having a diameter of 0.5 mm and a length of 1 mm was used, a load of 100 kgf and a temperature rising rate of 3 ° C. / When the melt viscosity was measured under the conditions of minutes, the melt viscosity at 120 ° C. was 1 × 10 ⁴ Pa · S.

In a flask equipped with a stirrer, a reflux condenser, and a thermometer, 30 parts of the particulate polymer (a) and 80 parts of ion-exchanged water are heated and stirred until the internal temperature reaches 80 ° C. I'm sorry. To this, styrene 49%, methyl methacrylate 45%, acrylic acid 4% and divinylbenzene (DV
B) A solution prepared by dissolving 70 parts of a monomer mixture having a composition of 2% and 0.6 parts of sodium persulfate in 20 parts of ion-exchanged water is added over 3 hours, and then stirred at 80 ° C. for 2 hours. After cooling, it was cooled. The obtained particulate polymer is referred to as a particulate polymer (b). The solid content concentration of the obtained particulate polymer (b) dispersion was 50.1%, and the particle diameter of the particulate polymer (b) was 0.45 µ as observed with an electron microscope. The obtained dispersion was dried to obtain a powder of the particulate polymer (b), and the melt viscosity was measured under the same conditions using a flow tester.
Was 2 × 10 ⁵ Pa · S.

In a flask equipped with a stirrer, a reflux condenser, and a thermometer, 47% of 100 parts of the particulate polymer (b) was added.
The aqueous dispersion was added, and the mixture was heated and stirred until the internal temperature reached 60 ° C. 5 parts of styrene and 10 parts of hexane were finely dispersed in 15 parts of ion-exchanged water using an ultrasonic homogenizer in the presence of 0.05 part of sodium lauryl sulfate, and added at 60 ° C. for another 5 hours. I was agitated.
To this, a solution prepared by dissolving 0.3 part of sodium persulfate in 5 parts of ion-exchanged water was added, and the mixture was further stirred at 60 ° C. for two and a half hours and then cooled. The solid content concentration of the obtained dispersion is 4
2.4%. Observation of the appearance of the obtained polymer particles with an electron microscope revealed that the particle size was 0.47 μm and the particle size distribution was extremely small. When a cross section of the obtained polymer particles was observed with an electron microscope, a pore of 0.21 μm was observed. When the cross section of the aggregated particles having the inner holes from which hexane was removed in the same manner as in Example 1 was observed with an electron microscope, no shrinkage of the inner holes occurred. The dispersion of the polymer particles having inner pores from which hexane had been removed was dried with a spray drier to obtain powder of polymer particles having inner pores.

[0021]

Example 3 A 47% aqueous dispersion of 100 parts of the particulate polymer (b) used in Example 2 was placed in a flask equipped with a stirrer, a reflux condenser, and a thermometer. 60 ° C
Heated and stirred until it became To this, 10 parts of styrene and 30 parts of hexane were added to sodium lauryl sulfate 0.0%.
In the presence of 5 parts, a solution finely dispersed in 40 parts of ion-exchanged water using an ultrasonic homogenizer was added, and the mixture was further stirred at 60 ° C for 5 hours. To this, a solution prepared by dissolving 0.3 part of sodium persulfate in 5 parts of ion-exchanged water was added, and the mixture was further stirred at 60 ° C. for two and a half hours and then cooled. The solid content concentration of the obtained dispersion was 37.0%, and the particle size of the polymer particles was 0.50 μm. When a cross section of the obtained polymer particles was observed with an electron microscope, a pore of 0.31 μm was observed. When a cross section of the polymer particles having inner holes from which hexane was removed in the same manner as in Example 1 was observed with an electron microscope, no shrinkage of the inner holes occurred.

[0022]

EXAMPLE 4 3.7 parts of seed particles having a particle diameter of 0.1 μm and 100 parts of ion-exchanged water were placed in a flask equipped with a stirrer, a reflux condenser, and a thermometer. Heated and stirred until it was. A mixture of 100 parts of styrene and 5 parts of t-dodecyl mercaptan was added to 0.8 parts of sodium persulfate.
A part thereof dissolved in 20 parts of ion-exchanged water was added over 4 hours, and the mixture was further stirred at 80 ° C. for 2 hours and cooled. The obtained particulate polymer is referred to as a particulate polymer (a). The solid content concentration of the obtained particulate polymer (a) dispersion was 47.7%, and the particulate polymer (a)
Was 0.3 μm when observed with an electron microscope. The obtained dispersion is dried to obtain a particulate polymer (a).
Of 0.5 m in diameter using a flow tester.
The melt viscosity was measured using a nozzle having a load of 100 kgf and a heating rate of 3 ° C./min using a nozzle having a length of 1 mm and a length of 1 mm.
The melt viscosity at 20 ° C. was 2 × 10 ⁴ Pa · S.

In a flask equipped with a stirrer, a reflux condenser, and a thermometer, 30 parts of the particulate polymer (a) and 80 parts of ion-exchanged water are heated and stirred until the internal temperature reaches 80 ° C. I'm sorry. A solution prepared by dissolving 70 parts of a monomer mixture composed of 49% of styrene, 45% of methyl methacrylate, 4% of acrylic acid, and 2% of divinylbenzene and 0.6 part of sodium persulfate in 20 parts of ion-exchanged water was used. It was added over 3 hours, then stirred at 80 ° C. for 2 hours and cooled. The obtained particulate polymer is referred to as a particulate polymer (b). The obtained particulate polymer (b)
The solid concentration of the dispersion was 50.1%, and the particle size of the particulate polymer (b) was 0.45 as observed with an electron microscope.
μ. The obtained dispersion was dried to obtain a powder of the particulate polymer (b), and the melt viscosity was measured under the same conditions using a flow tester. The melt viscosity at 150 ° C. was 3 × 10 ⁵ Pa. -It was S.

In a flask equipped with a stirrer, a reflux condenser and a thermometer, 47% of 100 parts of the particulate polymer (b) was added.
The aqueous dispersion was added, and the mixture was heated and stirred until the internal temperature reached 60 ° C. To this, 10 parts of styrene and 30 parts of hexane were finely dispersed using an ultrasonic homogenizer in 40 parts of ion-exchanged water in the presence of 0.05 part of sodium lauryl sulfate, and added at 60 ° C. for another 5 hours. I was agitated. To this, a solution prepared by dissolving 0.3 part of sodium persulfate in 5 parts of ion-exchanged water was added, and the mixture was further stirred at 60 ° C. for two and a half hours and then cooled. The solid content concentration of the obtained dispersion was 37.0%, and the particle size of the polymer particles was 0.50 μm. When a cross section of the obtained polymer particles was observed with an electron microscope, a pore of 0.30 μm was observed. When a cross section of the polymer particles having an inner hole from which hexane was removed in the same manner as in Example 1 was observed with an electron microscope, no shrinkage of the inner hole occurred.

[0025]

Comparative Example 1 In a flask equipped with a stirrer, a reflux condenser, and a thermometer, a monomer composed of 21% of styrene, 50% of methyl methacrylate, 25% of acrylonitrile, and 4% of acrylic acid was t-dodecyl mercaptan. A 40% aqueous dispersion of 100 parts of the particulate polymer having a particle diameter of 0.42 μ obtained by emulsion copolymerization with 2% was added, and the internal temperature was 70%.
Heated and stirred to ℃. In addition, styrene 10
A mixture of 0 parts and 30 parts of heptane and a solution prepared by dissolving 0.8 parts of sodium persulfate in 80 parts of ion-exchanged water were added over 5 hours, stirred at 70 ° C. for further 3 and a half hours, and cooled. The solid content concentration of the obtained dispersion is 43.5.
%, And when the appearance of the polymer particles was observed with an electron microscope, the particle size distribution was large. When the cross section of the obtained polymer particles was observed with an electron microscope, pores were observed but had a distribution in size.

[0026]

Comparative Example 2 30 parts of the particulate polymer particles (a) used in Example 2 and 80 parts of ion-exchanged water were placed in a flask equipped with a stirrer, a reflux condenser, and a thermometer. Is 80
Heated and stirred to ℃. Styrene 51
%, Methyl methacrylate 45% and acrylic acid 4%
A solution prepared by dissolving 70 parts of a monomer mixture having the following composition and 0.6 parts of sodium persulfate in 20 parts of ion-exchanged water was added over 3 hours, and then stirred at 80 ° C. for 2 hours, followed by cooling. did. The particulate polymer obtained here is referred to as particulate polymer (b). The solid content concentration of the obtained particulate polymer (b) dispersion was 50.1%, and the particle diameter of the particulate polymer (b) was 0.45 µ as observed with an electron microscope. The obtained dispersion was dried to obtain a powder of the particulate polymer (b), and the melt viscosity was measured under the same conditions using a flow tester.
Was 4 × 10 ³ Pa · S.

In a flask equipped with a stirrer, a reflux condenser, and a thermometer, 47% of 100 parts of the particulate polymer (b) was added.
The aqueous dispersion was added, and the mixture was heated and stirred until the internal temperature reached 60 ° C. To this, 10 parts of styrene and 30 parts of hexane were finely dispersed using an ultrasonic homogenizer in 40 parts of ion-exchanged water in the presence of 0.05 part of sodium lauryl sulfate, and added at 60 ° C. for another 5 hours. I was agitated. To this, a solution prepared by dissolving 0.3 part of sodium persulfate in 5 parts of ion-exchanged water was added, and the mixture was further stirred at 60 ° C. for two and a half hours and then cooled. The solid content concentration of the obtained dispersion was 37.0%, and the particle size of the polymer particles was 0.48 μm. When a cross section of the obtained polymer particles was observed with an electron microscope, a hole of 0.22 μ was observed. However, a cross section of the polymer particles from which hexane was removed in the same manner as in Example 1 was observed with an electron microscope. The inner hole had disappeared.

[0028]

Comparative Example 3 3.7 parts of seed particles having a particle diameter of 0.1 μm and 100 parts of ion-exchanged water were placed in a flask equipped with a stirrer, a reflux condenser, and a thermometer. Heated and stirred until it was. A mixture of 100 parts of styrene, 0.8 parts of t-dodecyl mercaptan and 0.8 parts of sodium persulfate dissolved in 20 parts of ion-exchanged water was added thereto over 4 hours, and then further added at 80 ° C. for 2 hours. After stirring, the mixture was cooled. The obtained particulate polymer is referred to as a particulate polymer (a). The obtained particulate polymer (a)
The solid concentration of the dispersion was 46.7%, and the particle size of the particulate polymer (a) was 0.3 μm when observed with an electron microscope.
Met. The obtained dispersion was dried to obtain a powder of the particulate polymer (a).
Using a nozzle of 5mm length 1mm, load 100kg
f, When the melt viscosity was measured at a temperature rising rate of 3 ° C./min, the melt viscosity at 120 ° C. was 5 × 10 ⁵ Pa · S.

In a flask equipped with a stirrer, a reflux condenser, and a thermometer, 30 parts of the particulate polymer (a) and 80 parts of ion-exchanged water are heated and stirred until the internal temperature reaches 80 ° C. I'm sorry. A solution prepared by dissolving 70 parts of a monomer mixture composed of 49% of styrene, 45% of methyl methacrylate, 4% of acrylic acid, and 2% of divinylbenzene and 0.6 part of sodium persulfate in 20 parts of ion-exchanged water was used. It was added over 3 hours, then stirred at 80 ° C. for 2 hours and cooled. The obtained particulate polymer is referred to as a particulate polymer (b). The obtained particulate polymer (b)
The solid concentration of the dispersion was 50.1%, and the particle size of the particulate polymer (b) was 0.45 as observed with an electron microscope.
μ. The obtained dispersion was dried to obtain a powder of the particulate polymer (b), and the melt viscosity was measured under the same conditions using a flow tester. The melt viscosity at 150 ° C. was 1 × 10 ⁶ Pa.s. S.

In a thrusco equipped with a stirrer, reflux condenser and thermometer, 47% of 100 parts of the particulate polymer (b) was added.
The aqueous dispersion was added, and the mixture was heated and stirred until the internal temperature reached 60 ° C. To this, 10 parts of styrene and 30 parts of hexane were finely dispersed using an ultrasonic homogenizer in 40 parts of ion-exchanged water in the presence of 0.05 part of sodium lauryl sulfate, and the mixture was further stirred at 60 ° C. for 5 hours. I'm sorry.
To this, a solution prepared by dissolving 0.3 part of sodium persulfate in 5 parts of ion-exchanged water was added, and the mixture was further stirred at 60 ° C. for two and a half hours and then cooled. The solid content concentration of the obtained dispersion is 3
It was 7.0%, and the particle size of the polymer particles was 0.46 μm. When a cross section of the obtained polymer particles was observed with an electron microscope, no holes were observed.

[0031]

Comparative Example 4 The same operation as in Example 3 was performed except that hexane in Example 3 was changed to toluene. The solid content concentration of the obtained dispersion was 37.0%, and the particle size of the polymer particles was 0.50 μm. When a cross section of the obtained polymer particles was observed with an electron microscope, no holes were observed. After removing toluene from the obtained polymer particles in the same manner as in Example 1, when the cross section of the polymer particles was observed with an electron microscope, no holes were observed.

[0032]

Comparative Example 5 A 47% aqueous dispersion of 100 parts of the particulate polymer (b) used in Example 2 was placed in a flask equipped with a stirrer, a reflux condenser, and a thermometer. 60 ° C
Heated and stirred until it became To this was added 30 parts of hexane, which was finely dispersed in 30 parts of ion-exchanged water using an ultrasonic homogenizer in the presence of 0.05 part of sodium lauryl sulfate, and the mixture was further stirred at 60 ° C. for 7 and a half hours. After cooling. After cooling, a large amount of hexane was separated in the flask, and the particle diameter remained at 0.45 μm.
When a cross section of the obtained polymer particles was observed with an electron microscope, no holes were observed.

Table 1 shows the main points of the above Examples and Comparative Examples.
Put together.

[0034]

[Table 1]

[0035]

According to the method for producing polymer particles having inner pores of the present invention, it is very easy to control the particle diameter and the inner pore diameter, and it is possible to obtain those having inner pores larger than the particle diameter. it can. In addition, the polymer particles having an inner hole produced by this method do not shrink when the solvent is removed, have excellent drying properties, and are excellent as hollow organic pigments in paints and coated papers. Has performance.

Continuation of the front page (56) References JP-A-57-133132 (JP, A) JP-A-53-129276 (JP, A) JP-B-46-3062 (JP, B1) (58) Fields investigated (Int) .Cl. ⁷ , DB name) C08F 2/44 C08F 257/02

Claims (1)

(57) [Claims] 1. A method for producing a polymer particle having an inner hole, which is obtained by the following (Step 1) and (Step 2).
Use of a particulate polymer (b) as a particulate polymer (A)
And 1 to 10 parts by weight of a polymerizable vinyl monomer (B) in a dispersion medium containing 100 parts by weight of the particulate polymer (A);
And polymer particles having 1 to 100 parts by weight of a non-polymerizable organic solvent (C) which is substantially incompatible with the above-mentioned polymer particles having an inner hole, and polymerized. Manufacturing method. (Step 1) Melting at 120 ° C.
When the melt viscosity is 10 ⁵ Pa · S (Pascal · second) or less
Water-dispersible particulate polymer having a particle size of 0.1 to 2 μm
(A) a step of polymerizing; (Step 2) Particulate polymer (a)
As a seed particle, a monomer having a composition different from that used during the polymerization of the seed particle.
The particles are added to a dispersion medium and polymerized to give a particle size of 0.2 to 5 μm.
And the melt viscosity at 150 ° C. is 10 ⁴ Pa · S
A step of obtaining the water-dispersible particulate polymer (b) described above.