JPH05125127A - Polymer granule having single inner pore - Google Patents

Abstract

PURPOSE:To provide the title granules having a specific constitution, excellent in mechanical strength, heat resistance, whiteness and gloss because of having in each granule a single inner pare discrete from the polymer layer, and useful as a lightweight, highly water and oil-absorbing filler. CONSTITUTION:The objective polymer granules made up of (A) 100 pts.wt. of a cross-linked copolymer from (1) 1-50wt.% of a cross-linkable monomer (pref. divinylbenzene), (2) 50-1wt.% of a hydrophilic monomer (pref. methyl methacrylate) and (3) 0-85wt.% of another monomer copolymerizable with the component 1 or 2 (pref. styrene) and (B) 1-100 pts.wt. of a second polymer differing in composition from the component A (pref. polystyrene). With the component A, a hollow body per granule is formed where its outer diameter is 0.05-10mum and inner diameter 0.2-0.95 times the outer diameter. Said granules can be obtained, for example, by dissolving the component B in the components 1, 2 and 3 followed by finely dispersing the resultant solution in an aqueous dispersion medium and then carrying out polymerization of the components 1, 2 and 3.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to polymer particles having a single internal pore.

[0002]

2. Description of the Related Art At present, polymer particles having pores inside are used as microcapsule particles by incorporating various substances in the inner pores, or as light scattering materials by making the inner pores hollow. It is widely used as an organic material such as hollow polymer particles.

Conventionally, polymer particles having internal pores are
(1) A method in which a foaming agent is contained in polymer particles and then the foaming agent is foamed, (2) a volatile substance such as butane is sealed in the polymer, and the volatile substance is gasified and expanded later. Method, (3) a polymer is melted, and a jet of gas such as air is blown to the polymer to enclose air bubbles, (4) an alkali-swellable substance is contained in the inside of the polymer particle, and the polymer particle A method of swelling an alkali-swelling substance by infiltrating an alkaline liquid into the
(5) A method in which fine particles of polymethylmethacrylate are used as seed particles, and styrene is emulsion-polymerized in the presence of the seed particles. (6) A polymerizable monomer component is finely dispersed in water to prepare an oil-in-water emulsion. It is known to be produced by a method of carrying out polymerization, or the like.

[0004]

However, according to these methods, it is not possible to obtain polymer particles having a single inner pore due to the crosslinked polymer, and as a result, the polymer particles have a large strength and a single inner diameter. No small size polymer particles with pores are provided.

The present invention is a polymer particle having a small particle size, which is composed of a hollow cross-linked copolymer, in which a single inner hole is formed so as to be surely partitioned from the polymer layer, and therefore the mechanical strength and An object of the present invention is to provide a polymer particle having a single inner hole, which has excellent properties such as heat resistance.

[0006]

The polymer particles according to the present invention comprise (a) 1 to 50% by weight of a crosslinkable monomer, (b) 1 to 99% by weight of a hydrophilic monomer, and (c) the crosslinkable monomer or hydrophilic group. 100 parts by weight of a copolymer cross-linked with a polymerizable monomer component consisting of 0 to 85% by weight of another polymerizable monomer copolymerizable with a polymerizable monomer, and 1 to 100 parts by weight of a different polymer having a different composition from the copolymer. The crosslinked copolymer forms a hollow body having an outer diameter of 0.05 to 10 μm and an inner diameter of 0.2 to 0.95 times the outer diameter.

The polymer particles having a single inner pore of the present invention include, for example, 100 parts by weight of the above polymerizable monomer component and 1 to 100 parts by weight of fine particles of a different polymer having a composition different from that of the copolymer of the polymerizable monomer component. Part of the heterogeneous polymer to absorb the polymerizable monomer component and then polymerize the polymerizable monomer component, and 100 parts by weight of the polymerizable monomer component 1-100
It can be produced by a method of dissolving parts by weight, finely dispersing the solution in an aqueous dispersion medium, and then polymerizing the polymerizable monomer component.

[0008]

The polymer particles having a single inner hole of the present invention are
Despite having a small particle diameter of 10 μm or less, the shell is made of a cross-linked copolymer, and therefore has excellent mechanical strength and heat resistance, and has a single inner hole. Since it is formed by a hollow portion having a diameter larger than the outer diameter of the polymer particle, the inner hole can be utilized for various purposes.

The mechanism by which a single inner hole is formed inside a polymer particle as in the present invention is not necessarily clear, but in the process of producing the polymer particle of the present invention, a crosslinkable monomer is added in an aqueous dispersion medium. The heterogeneous polymer in addition to the polymerizable monomer containing the coexistence in the form of fine particles or a solution forms a nucleus in the dispersed particles due to phase separation of the heterogeneous polymer at the time of polymerization, and is being generated in this nucleus. Polymerization shrinkage of the polymer, that is, volume change when the polymerizable monomer is polymerized and converted into the polymer is effectively concentrated, and as a result, a single inner hole is formed inside the polymer and the cross-linked polymer is hollow. It is considered that the body is formed and the heterogeneous polymer exists in a state of being attached to the inner surface side of the hollow body.

Since the crosslinkable monomer is used as an essential component of the polymerizable monomer, the polymerization shrinkage simultaneously progresses at the point where the polymer particles formed by the crosslinking reaction during the polymerization reaction are difficult to be deformed and the particles shrink. It is presumed that internal strain occurs, but this strain concentrates on the heterogeneous polymer inside the particle as a nucleus, and as a result, a single inner hole is generated inside the polymer particle and expands. By the way, when the different polymer is not present, a single inner pore is not formed, and countless minute pores are simply generated inside the particle to form a porous particle.

Further, the presence of the oily substance together with the different polymer makes it possible to obtain polymer particles whose inner pore diameter is controlled. Further, the hollow polymer particles can be obtained by removing the water or oily substance from the polymer particles having inner pores. In addition, the oily substance contained in the inner pores is left as it is, or the hollow polymer particles obtained as described above are allowed to absorb various substances depending on the purpose, thereby forming a capsule shape. Polymer particles can be obtained.

The present invention will be described in detail below. The polymer particle having a single inner pore of the present invention is a polymer of a polymerizable monomer component comprising (a) a crosslinkable monomer, (b) a hydrophilic monomer, and (c) another monomer optionally used, That is, it is composed of a cross-linked copolymer. Examples of the (a) crosslinkable monomer include divinylbenzene, ethylene glycol dimethacrylate, and 1,3-
Examples thereof include divinyl-based monomers or trivinyl-based monomers such as butylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and allyl methacrylate, and divinylbenzene, ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate are particularly preferable.

The amount of the crosslinkable monomer used is usually 1 to 50 parts by weight, preferably 2 to 20 parts by weight, based on 100 parts by weight of all the monomer components. The amount of the crosslinkable monomer used here is a pure product excluding the inert solvent and the monofunctional non-crosslinkable monomer component that are usually contained in the crosslinkable monomer material. If the amount of the crosslinkable monomer used is too small, the strength of the particles during polymerization will be insufficient and the entire particles will shrink, resulting in insufficient distortion due to polymerization shrinkage inside the particles and forming a single inner hole. However, even if polymer particles having a single inner hole are formed, the strength of the polymer particles will be reduced. On the other hand, if the amount of the crosslinkable monomer used is too large, the heterogeneous polymer tends to be rejected to the outside of the polymer particles generated during the polymerization, and the resulting polymer particles do not have a true spherical shape,
The problem arises that the particles become uneven and lumpy.

Examples of the hydrophilic monomer (b) include vinyl pyridine, glycidyl acrylate, glycidyl methacrylate, methyl acrylate, methyl methacrylate, acrylonitrile, acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, acrylic acid and methacrylic acid. Acid, itaconic acid, fumaric acid, sodium styrene sulfonate, vinyl acetate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, 2-hydroxyethyl methacrylate, vinyl monomers such as 2-hydroxypropyl methacrylate can be exemplified, in particular, 5 to 99% by weight, preferably 5 to 90% by weight of methyl methacrylate, vinyl pyridine,
2-hydroxyethyl methacrylate, and 1-40
Unsaturated carboxylic acids, such as methacrylic acid, used in proportions by weight, preferably 1 to 20% by weight, are preferred.

These hydrophilic monomers preferably have a solubility in water of 0.5% by weight or more, particularly 1% by weight or more. The amount of the hydrophilic monomer used varies depending on the type and amount of the different polymer used, the presence or absence of an oily substance, the type, etc., but is usually 1 to 99 parts by weight, preferably 100 parts by weight of the total monomer components. Is 5
It is preferably in the range of 99 parts by weight, particularly 50 to 95 parts by weight.

The proportion of unsaturated carboxylic acid used as the hydrophilic monomer is 1 to 40% by weight, preferably 1 to 20% by weight. When the hydrophilic monomer is vinyl pyridine or 2-hydroxyethyl methacrylate, the amount used is preferably 40% by weight or less. A crosslinkable monomer having a high hydrophilicity, such as ethylene glycol dimethacrylate or glycidyl methacrylate, can be used as a crosslinkable monomer and a hydrophilic monomer at the same time. If the amount of hydrophilic monomer used is too small, the phase separation of the dissimilar polymer may be insufficient, or the dissimilar polymer may be exposed on the surface of the polymer particles, resulting in uncertain formation of inner pores. Occurs.

The above-mentioned (c) the monomer used as necessary is not particularly limited as long as it has radical polymerizability, and it is aromatic such as styrene, α-methylstyrene, p-methylstyrene, halogenated styrene and the like. Vinyl monomers, vinyl esters such as vinyl propionate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, lauryl acrylate, alkyl esters of ethylenically unsaturated carboxylic acid such as lauryl methacrylate, butadiene And conjugated diolefins such as isoprene can be exemplified, and styrene is particularly preferable.

In the polymerization reaction of the polymerizable monomer, the presence of the different polymers in the aqueous dispersion promotes the formation of inner pores inside the polymer particles during the polymerization. The different polymer is at least a polymer of a different type or composition from the polymer obtained by polymerizing the polymerizable monomers (a) to (c), and is easily soluble in the polymerizable monomer. Is required.

Specific examples of such different polymers include polystyrene, carboxy-modified polystyrene, carboxy-modified styrene butadiene copolymer, styrene butadiene copolymer, styrene acrylic ester copolymer, styrene methacrylic ester copolymer, acrylic ester copolymer, methacrylic ester copolymer, Examples thereof include carboxy-modified styrene acrylic ester copolymer, carboxy-modified styrene methacrylic ester copolymer, carboxy-modified acrylic ester copolymer, and carboxy-modified methacrylic ester copolymer. Of these, polystyrene or a styrene copolymer containing 50% by weight or more of a styrene component is particularly preferable.

The amount of the different polymer used is 10 total monomers.
0 to 100 parts by weight, preferably 2 to 50 parts by weight
Parts by weight, more preferably 5 to 20 parts by weight. When the amount of the different polymer used is less than 1 part by weight, the effect of forming a single inner hole is small, while the amount of the different polymer used is 10
If it is more than 0 parts by weight, the problem that the formation of a single inner hole tends to be suppressed occurs.

As a method for carrying out the polymerization in the presence of the different polymer in the aqueous dispersion, (1) the different polymer is used in the form of solid fine particles, the fine particles are dispersed in an aqueous medium, and the polymerizable monomer and If necessary, a method of polymerizing after absorbing an oily substance and (2) dissolving a heterogeneous polymer in a polymerizable monomer and, if necessary, an oily substance to form a solution, and dispersing this oily solution in an aqueous dispersion medium. It is possible to employ a method of performing post-polymerization and the like.

When the dissimilar polymer is used in the form of particles by the method (1), it functions as seed polymer particles, and the polymerizable monomer and the oily substance are absorbed therein, so that the dissimilar polymer is used. Preferably has good absorbability of the polymerizable monomer and the oily substance. For that purpose, it is preferable that the different polymer has a small molecular weight, for example, the number average molecular weight is 20,000 or less, preferably 10,000 or less, and more preferably 700 to 7,000. In addition, the number average molecular weight here is obtained by dissolving a different polymer in a good solvent thereof and subjecting the obtained solution to gel permeation chromatography (GPC), an osmotic pressure molecular weight measuring device, a vapor pressure lowering method molecular weight measuring device and the like. It is obtained by measuring in.

The number average molecular weight of the different polymer is 20,000
When it is larger than 0, the amount of the monomer which is not absorbed by the seed polymer particles increases, and this polymerizes separately from the seed polymer particles in the aqueous dispersion, so that not only a large amount of fine particles which do not become polymer particles having inner pores are generated. However, the problem arises that the polymerization system becomes unstable. The particle size of the different polymer used as the seed polymer particles is preferably 0.3 to 0.8 times the outer diameter of the polymer particles having the desired inner pores. The method for producing the different polymer used as such seed polymer particles is not particularly limited, but for example, a production method such as emulsion polymerization or suspension polymerization using a relatively large amount of a chain transfer agent can be used.

When a different polymer is used as the seed polymer particles, a high lipophilic substance having a solubility in water of 10 ^-3 % by weight or less is absorbed in advance in the seed polymer particles, whereby It is possible to increase the absorption capacity of the polymerizable monomer and the oily substance. When the means for absorbing the highly lipophilic substance into the seed polymer particles is used as described above, the number average molecular weight of the different polymer does not have to be 20,000 or less. Examples of the highly lipophilic substance include 1-chlorodecane, octanoyl peroxide, and 3,5,5-trimethylhexanoyl peroxide. In order to absorb these highly lipophilic substances into the seed polymer particles, an aqueous dispersion in which the highly lipophilic substance is finely dispersed is prepared, and this dispersion is mixed with an aqueous dispersion of the seed polymer particles. It is advisable to bring the highly lipophilic substance into contact with the seed polymer particles.

The particle size of the polymer particles having inner pores obtained when the seed polymer particles are used is approximately the same as the particle size of the particles swelled by the seed polymer particles absorbing the polymerizable monomer and the oily substance. Therefore, by adjusting the particle size of the seed polymer particles, the relative amount of the seed polymer particles used with respect to the polymerizable monomer and the oily substance, etc., the particle size of the polymer particles having inner pores to be generated can be controlled. Specifically, in the production of polymer particles having inner pores, in order to obtain hollow polymer particles having a particle size of 0.1 to 0.6 μm, which is excellent in whiteness and hiding power, 0 as seed polymer particles is required. .06-0.
A particle size of 40 μm may be used. In addition, the use of seed polymer particles is particularly advantageous in that, when polymer particles having small diameter inner pores having a particle diameter of 1 μm or less are produced, monomer droplets having a small diameter can be easily and stably formed. preferable.

When the different polymer is used in the above method (2), the molecular weight of the different polymer is not particularly limited,
Those having a number average molecular weight of 20,000 or more can be preferably used.

In the present invention, an oily substance can be used if necessary, and such an oily substance is not particularly limited as long as it is a lipophilic substance having a solubility in water of 0.2% by weight or less. Any of animal oils, mineral oils and synthetic oils can be used. In the present invention, it is possible to obtain polymer particles having inner pores without using an oily substance, but by using an oily substance, it is possible to reliably control the diameter of the inner pores by adjusting the amount used. You can

Examples of the oily substance include lard oil, olive oil, coconut oil, castor oil, cottonseed oil, kerosene, benzene, toluene, xylene, butane, pentane, hexane, cyclohexane, carbon disulfide, carbon tetrachloride and the like. You can Further, as the oily substance, eugenol, geraniol, cyclamenaldehyde, citronellal, dioctyl phthalate, dibutyl phthalate and other high boiling point oils can also be used. When these high boiling point oils are used, capsule-shaped polymer particles having a core containing a fragrance, a plasticizer and the like can be obtained.

The amount of the oily substance used is usually 0 to 1,000 parts by weight, preferably 0 to 300 parts by weight, based on 100 parts by weight of all the monomer components. Inert solvents that are usually contained in those supplied as the crosslinkable monomer material can also be included in the oily substance here. If the amount of the above-mentioned oily substance used is too large, the monomer component is relatively insufficient, the thickness of the outer shell of the polymer becomes thin, and the strength of the capsule becomes insufficient, causing the problem of being easily crushed.

Further, the concept of the oily substance may include the above-mentioned polymerizable monomer. In this case,
In the polymerization step, by stopping the polymerization in the state where the polymerizable monomer remains inside the produced polymer particles, the remaining monomer can be used as an oily substance. In this case, the polymerization yield must be 97% or less, preferably 95% or less. For this purpose, a method of adding a small amount of a polymerization inhibitor for polymerization, a method of lowering the temperature of the reaction system during the polymerization, or a method of adding a polymerization terminator during the polymerization to stop the polymerization can be adopted. ..

The oily substances include dyes, detergents, inks, fragrances, adhesives, medicines, agricultural chemicals, fertilizers, oils and fats, foods,
Enzymes, liquid crystals, paints, rust preventives, recording materials, catalysts, chemical reactants, magnetic substances, and various other substances that require physical protection by encapsulation against deterioration, evaporation, pressure during handling, etc. , Can be dissolved or dispersed depending on the application.

Polymerization of the above-mentioned polymerizable monomer is carried out in the form of minute dispersed oil droplets in which a different polymer and an oily substance added as required coexist. In the polymerization process, nuclei are generated by phase separation of different polymers,
A single inner hole is formed due to polymerization contraction with the cross-linking polymerization reaction of the polymer centering on this nucleus, and further water or the like enters the inner hole through the outer wall of the polymer, or when an oily substance is present, It is considered that the oily substance concentrates in the inner hole and the inner hole expands.

From the viewpoint that this polymerization reaction proceeds in the droplets dispersed in the aqueous dispersion medium,
Essentially considered suspension polymerization. However, as in the case of the above-mentioned method (1), by using the seed polymer particles in the form of fine particles, the outer diameter of the obtained polymer particles is about 0.1 to 0.6 μm, and the surface activity during the polymerization is small. In view of the fact that an agent and a water-soluble polymerization initiator can also be used, a polymerization form apparently similar to emulsion polymerization can be adopted.

In this polymerization reaction, as the dispersion stabilizer, a surfactant used in ordinary polymerization, or an organic or inorganic suspension protective agent and a dispersant can be used. Generally, in the case of producing polymer particles having inner pores with a particle size smaller than about 1 μm,
When a surfactant is mainly used and polymer particles having inner pores with a particle size larger than about 1 μm are produced, a suspension protective agent is preferably used mainly.

Examples of the surfactant include anionic emulsifiers such as sodium dodecylbenzene sulfonate, sodium lauryl sulfate, sodium dialkylsulfosuccinate, and formalin condensate salt of naphthalene sulfonic acid, and further polyoxyethylene nonylphenol ether. It is also possible to use nonionic surfactants such as polyethylene glycol monostearate and sorbitan monostearate together.

Examples of the organic suspension protector include hydrophilic synthetic polymer substances such as polyvinyl alcohol, polyvinylpyrrolidone and polyethylene glycol, natural hydrophilic polymer substances such as gelatin and water-soluble starch, carboxymethyl cellulose and the like. Examples thereof include hydrophilic semi-synthetic polymer substances. In addition, as the inorganic suspension protector, for example, magnesium, barium, phosphates such as calcium, calcium carbonate, magnesium carbonate,
Examples include zinc white, aluminum oxide, and aluminum hydroxide.

Examples of the dispersant include naphthalenesulfonic acid formalin condensate salt, styrene acrylic acid copolymer salt, and styrene maleic anhydride partial hydrolyzate.

As the polymerization initiator, either an oil-soluble polymerization initiator or a water-soluble polymerization initiator can be used.
However, using different polymers in the form of seed polymer particles,
In addition, when polymerizing polymer particles having a small particle diameter of about 1 μm or less, it is preferable to use a water-soluble polymerization initiator, whereby a large particle diameter which is not absorbed by the seed polymer particles. It is possible to prevent the polymerization of the monomer droplets. In other cases, it is preferable to use an oil-soluble polymerization initiator in order to prevent generation of unnecessary new polymer particles in addition to the intended polymer particles having inner pores.

Examples of the water-soluble polymerization initiator include persulfates, and redox initiators such as hydrogen peroxide-ferrous chloride, cumene hydroperoxide-sodium ascorbate. Examples of the oil-soluble polymerization initiator include berezoyl peroxide, lauroyl peroxide, t-butylperoxy-2-ethylhexanoate and azobisisobutyronitrile.

In the polymerizable monomer component for the crosslinked copolymers that make up the polymer particles of the present invention,
Since the amount of the crosslinkable monomer used is relatively large, the polymerization rate is often high. For this reason, when conducting polymerization in a large polymerization vessel, if the so-called batch polymerization method is used, in which all of the polymerization components are placed in the polymerization vessel, it is difficult to control the temperature of the polymerization system and the polymerization reaction may runaway. There is. Therefore, in the present invention, in order to avoid such a danger, generally, a so-called increment weight is used in which the monomer component is supplied to the polymerization vessel continuously or in a divided state during the polymerization as it is or as an emulsion. Legalization can also be adopted. It is preferable that the polymerizable monomer, the oily substance and the different polymer are supplied to the polymerization system in the state of a dispersion in which these coexist in the same dispersed particles.

When an oily substance is used in the polymerization reaction, the oily substance is benzene, toluene, xylene,
In the case of a relatively volatile solvent or monomer such as butane, pentane, hexane, cyclohexane, methyl methacrylate, etc., the obtained dispersion of polymer particles having inner pores is subjected to a reduced pressure treatment, a distillation treatment, a steam strip treatment. By performing a gas bubbling treatment or a treatment using these treatments in combination, the oily substance can be easily replaced with water, and as a result, water-containing hollow polymer particles containing water therein can be obtained. Further, a hollow polymer having an internal space by separating the capsule-shaped polymer particles containing an oily substance or the water-containing hollow polymer particles obtained by replacing the oily substance with water as described above from the aqueous dispersion medium and subjecting to drying treatment. Particles are obtained.

The hollow polymer particles are useful as a plastic pigment excellent in gloss and hiding power.
Further, obtained by the present invention, the capsule-shaped polymer particles containing an oily substance inside, or perfume, chemicals, agricultural chemicals, useful components such as ink components in the inner pores of the hollow polymer particles, immersion treatment, reduced pressure or pressure immersion treatment, etc. The capsule particles obtained by encapsulating by the means described above can be used for various purposes depending on the useful components contained inside.

[0043]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited thereto. Example 1 A latex containing styrene / butadiene polymer particles (butadiene content 45%) having a particle size of 0.25 μm and a number average molecular weight of 6,800 was obtained by emulsion polymerization using a large amount of t-dodecyl mercaptan as a molecular weight modifier. ..
Using this latex as seed polymer particles, 4 parts of this latex (2 parts as solid content), 30 parts of 1% aqueous solution of sodium lauryl sulfate, 5% of polyvinyl alcohol
20 parts of the aqueous solution and 100 parts of water were uniformly mixed.

A dispersion liquid was obtained by finely dispersing a mixture of the following substances, methyl methacrylate 80 parts divinylbenzene 20 parts toluene 30 parts benzoyl peroxide 2 parts 0.1% sodium lauryl sulfate aqueous solution 400 parts with an ultrasonic disperser. Plus 3
When the mixture was slowly stirred for a time, the monomer components of the dispersion and substances such as an oily substance were uniformly absorbed by the seed polymer particles made of a styrene / butadiene copolymer. When this was polymerized at 75 ° C. for 6 hours, polymer particles were obtained with a polymerization yield of 98%.

When this dispersion liquid of polymer particles was applied to a glass plate and allowed to stand at room temperature for 10 minutes, water and toluene were evaporated to obtain polymer particles. When the polymer particles were observed with an optical microscope, it was confirmed that they were hollow polymer particles having high whiteness. When the hollow polymer particles were observed with a transmission electron microscope, the particles had an outer diameter of 0.95 μm and an inner pore diameter (inner diameter) of 0.
It was found to be spherical hollow particles with no dents of 5 μm. After drying the hollow particles, the particles were placed in a liquid of fragrance terpinolene, and the pressure reducing operation and the pressure applying operation were repeated. As a result, the inside of the hollow particles could be filled with terpinolene. When this is left at room temperature, 1
It was confirmed that the fragrance was emitted even after a lapse of months.

Example 2 10 parts of a commercially available polystyrene resin (manufactured by Nippon Steel Chemical Co., Ltd., number average molecular weight: 150,000), 20 parts of toluene, 90 parts of methyl methacrylate, 10 parts of divinylbenzene (converted to a pure product) and 3 parts of benzoyl peroxide. Dissolved in the mixture.
This solution was placed in an aqueous solution in which 10 parts of polyvinyl alcohol was dissolved in 800 parts of water, and polymerization was carried out at 80 ° C. for 4 hours while stirring. The polymerization yield was 98%, and the particle size was 3 to 8
A dispersion of polymer particles of μm was obtained. When this was observed with an optical microscope, it was found that the polymer particles were capsule particles having a double contour.

Next, steam was blown into the dispersion liquid of the polymer particles to carry out a steam strip treatment. As a result, toluene inside the polymer particles was removed, and water-containing hollow polymer particles containing water inside were obtained. The water-containing hollow polymer particles and the capsule particles containing toluene before the steam strip treatment were placed on a slide glass and observed under a microscope without a cover glass. Alternatively, it was observed that toluene was evaporated to form hollow particles. All the particles are hollow spherical particles without dents,
The ratio of the outer diameter to the inner hole diameter (hereinafter referred to as “outer diameter / inner diameter ratio”) was about 10/6.

Comparative Example 1 Polymer particles were obtained in the same manner as in Example 2 except that polystyrene resin was not used. The polymerization yield in this polymerization was 99%. The obtained polymer particles had a particle size of 3 to 10 μm, and as a result of observation by an electron microscope using an optical microscope and an embedded particle cutting method, it was confirmed that the inside was a solid particle. The polymer particles have a BET specific surface area of 180 m ^2.
Since it is / g, it is judged to be porous particles.

Examples 3 to 13 and Comparative Examples 2 to 4 The same as Example 2 except that the amount of polystyrene resin, the composition of the polymerizable monomer, and each kind and amount of the oily substance were changed as shown in Table 1. To produce polymer particles. Let these be Examples 3-13 and Comparative Examples 2-4. In addition, in Examples 3 and 11, no oily substance was used.

For the polymer particles obtained in these examples, the shape of the polymer particles in the dispersion after polymerization, the shape of the dried polymer particles and the outer diameter / inner diameter ratio thereof were determined in the same manner as in Example 2. .. The results are shown in Table 2.
Shown in. The outer diameter of the obtained polymer particles was 2
It was distributed in the range of 10 μm.

[0051]

[Table 1]

[0052]

[Table 2]

Example 14 98 parts of styrene, 2 parts of methacrylic acid and 10 parts of t-dodecyl mercaptan were placed in an aqueous solution prepared by dissolving 0.5 part of sodium lauryl sulfate and 1.0 part of potassium persulfate in 200 parts of water and stirring. While polymerizing at 70 ° C. for 8 hours, polymer particles were obtained. The polymer particles had an average particle size of 0.22 μm, a toluene insoluble content of 3%, a number average molecular weight of 4,100 by GPC, and a ratio of the weight average molecular weight to the number average molecular weight Mw / Mn = 2.4. Next, using the polymer particles as seed polymer particles, 10 parts of the polymer particles in solid content, 0.1 part of polyoxyethylene nonylphenyl ether, 0.3 part of sodium lauryl sulfate and 0.5 part of potassium persulfate are used. Dispersed in 900 parts of water. 80 parts of methyl methacrylate, 10 parts of divinylbenzene (converted to pure product), 10 parts of styrene and 2 parts of toluene
When 0 part of the mixture was added and stirred at 30 ° C. for 1 hour,
About half of the material was absorbed by the seed polymer particles. The rest was unabsorbed, but entered the polymerized particles as the polymerization proceeded.

When this was directly polymerized at 70 ° C. for 5 hours, a dispersion liquid of capsule particles containing toluene in the inside of the particles was obtained with a polymerization yield of 98%. After performing steam strip treatment on this dispersion, the polymer particles were observed by a transmission electron microscope, and it was found that the polymer particles were transparent at the center and were completely spherical capsule particles. .. The capsule-shaped polymer particles have an outer diameter of 0.
The inner diameter was 51 μm and the inner diameter was 0.3 μm. The electron micrograph is shown in FIG.

Examples 15 to 18 As seed polymer particles, monomer composition, particle size, number average molecular weight, ratio of weight average molecular weight to number average molecular weight Mw / M
Polymerization was carried out in the same manner as in Example 14 except that the ratios of n and toluene insoluble content shown in Table 3 were used.
Polymer particles were obtained. These are Examples 15-18. The results obtained are shown in Table 4.

In Example 18, since the number average molecular weight of the polymer constituting the seed polymer particles was as large as 23,000, the ability to absorb the monomer component and the oily substance was small, and it was not absorbed in addition to the intended capsule particles. Particle size generated by polymerization of monomers is 0.0
A large amount of fine particles of about 5 μm were mixed, and the polymerization system was unstable.

Examples 19 and 20, Comparative Examples 5 and 6 As the polymer particles, the monomer composition, particle size, number average molecular weight, and ratio of weight average molecular weight to number average molecular weight Mw / M.
Polymerization was carried out in the same manner as in Example 14 except that n, toluene insoluble content and the use amount shown in Table 3 were used to obtain polymer particles. These are Examples 19 and 20 and Comparative Examples 5 and 6. The results obtained are shown in Table 4.

In Example 20, the polymer particles were
The hollow particles had a slightly distorted shape. Comparative Example 5
In the above, since the amount of the seed polymer particles used was reduced to 0.5 part, many of the monomers could not be absorbed in the seed polymer particles, and a large amount of fine particles were generated by the polymerization of these to gelate the system. In Comparative Example 6, since the amount of the seed polymer particles used was as large as 150 parts, the seed polymer particles were too much relative to the polymerizable monomer, so that the formation of inner pores inside the particles during the polymerization was good. Since it did not occur at this time, it did not become hollow particles but became porous particles.

[0059]

[Table 3]

[0060]

[Table 4]

Examples 21 to 33, Comparative Examples 7 to 9 Except that 10 parts of the seed polymer particles used in Example 14 were used and the monomers and oily substances shown in Table 5 were used. Polymerize in the same way,
Polymer particles were obtained. Let these be Examples 21-33 and Comparative Examples 7-9. Note that no oily substance was used in Examples 26 and 28. Examples 14, 21, 22
And Comparative Examples 7 and 8 show examples in which the amount of the crosslinkable monomer used was changed. Examples 23 to 27 and Comparative Example 9 show examples in which the amount and type of hydrophilic monomer (acidic monomer) used were changed. Examples 29 to 31 show examples in which the amount of toluene used as an oily substance was changed. The results are shown in Table 6.

In Example 31, the shell of the hollow polymer particles was thin and was in a fragile state. Example 32
An example of using geraniol as a perfume as an oily substance will be shown. As a result, fragrant capsule particles were obtained. Example 33 shows an example using dibutyl phthalate as an oily substance. As a result, capsule particles containing dibutyl phthalate were obtained.

[0063]

[Table 5]

[0064]

[Table 6]

Examples 34 to 41 Polymerization was carried out in the same manner as in Example 14 except that 10 parts of the seed polymer particles used in Example 14 were used and the monomers and oily substances shown in Table 7 were used. ,
Polymer particles were obtained. These are Examples 34 to 41. The results obtained are shown in Table 8.

[0066]

[Table 7]

[0067]

[Table 8]

Examples 42 and 43 Polymerization was performed in the same manner as in Example 14 except that toluene as an oily substance was not used and the polymerization time was set to 1 hour and 2 hours, respectively, and the polymerization yields were 60% and 9%, respectively.
A dispersion of two polymer particles different from 0% was obtained. These are Examples 42 and 43. When these polymer particles were dried and observed with a transmission electron microscope, Example 4
2, the outer diameter of the polymer particles was 0.46μ.
m, the inner diameter was 0.2 μm, and in Example 43, the particles were completely spherical hollow particles having an outer diameter of 0.48 μm and an inner diameter of 0.2 μm.

Example 44 An aqueous dispersion of polystyrene particles (particle size 2 to 6 μm, number average molecular weight 6,200) prepared by suspension polymerization as a solid content of 20 parts, polyvinyl alcohol 3 parts and sodium lauryl sulfate 0.5. 45 parts of methyl methacrylate and 5 parts of divinylbenzene to a dispersion liquid in which 500 parts of water are added.
Part, 50 parts of styrene, 3 parts of benzoyl peroxide and 30 parts of cyclohexane were added, and the mixture was stirred for 3 hours to cause the polystyrene particles to substantially absorb the monomer component and the oily substance. Then, the temperature of the system was raised to 80 ° C. and polymerization was carried out for 6 hours. As a result, capsule-shaped polymer particles were obtained with a polymerization yield of 98%. The capsule-shaped polymer particles were filtered and then dried under reduced pressure to obtain hollow polymer particles having a particle diameter of 3 to 10 μm. The hollow polymer particles have an outer diameter /
The inner diameter ratio was about 10/6.

Example 45 5 parts of styrene-butadiene rubber "SBR # 1500" (manufactured by Japan Synthetic Rubber Co., Ltd.) was dissolved in a mixture of 60 parts of methyl methacrylate, 35 parts of styrene, 5 parts of divinylbenzene and 2 parts of benzoyl peroxide. This was put into 1,000 parts of water in which 10 parts of polyvinyl alcohol was dissolved, and the mixture was stirred, and then polymerized at 60 ° C. for 3 hours. When the polymerization yield reached 83%, the system was rapidly cooled to 20 ° C. As a result, a dispersion liquid of capsule particles having a particle diameter of 5 to 10 μm containing a methyl methacrylate monomer and water in the center was obtained with a polymerization yield of 86%. Steam strip this,
By drying, hollow particles having an outer diameter / inner diameter ratio of 10/6 were obtained.

Example 46 As seed polymer particles, an emulsion having a monomer composition of styrene / methyl methacrylate / acrylic acid = 20/78/2, a number average molecular weight of 3,800 and a particle diameter of 0.16 μm was used. Part (solid content) was dispersed in 200 parts of an aqueous solution in which 0.7 part of polyoxyethylene nonylphenyl ether, 0.3 part of sodium dodecylbenzenesulfonate and 0.5 part of potassium persulfate were dissolved. In addition to this, tetramethylolmethane triacrylate "NK Ester TMM-50T" was used as a monomer.
(Shin-Nakamura Chemical Co., Ltd., 50% active ingredient, balance toluene) 20 parts, vinyl pyridine 30 parts and styrene 6
0 part was added, and the oily substance was stirred at 40 ° C. for 30 minutes without adding anything other than toluene, which is a diluent in the NK ester, to be absorbed by the seed polymer particles. After that, the temperature was raised to 70 ° C. and the polymerization was carried out for 6 hours to obtain an emulsion of polymer particles with a polymerization yield of 98%.

1% of calcium chloride in this emulsion
Add 20 parts of an aqueous solution to agglomerate the particles, filter with a filter cloth,
The solid content thus obtained was dried in an infrared heating furnace at 90 to 140 ° C. to remove water and toluene to obtain hollow polymer particles having an outer diameter of 0.42 μm and an inner diameter of 0.15 μm.

Example 47 Dispersion 25 of seed polymer particles used in Example 14
Parts (solids 10 parts), sodium dodecylbenzene sulfonate 1 part, polyethylene glycol monostearate 2 parts and water 100 parts in a mixture with the following substances: methyl methacrylate 70 parts styrene 10 parts divinylbenzene 20 parts toluene 20 parts t -Butyl peroxy 2 ethylhexanoate A mixture of 2 parts was added and stirred to allow the seed polymer particles to absorb the above material.

10 liters of this mixed solution and 10 liters of water were placed in a polymerization vessel with a capacity of 120 liters equipped with a stirrer and a cooler, the temperature of the system was raised to 75 ° C. to start the polymerization, and 1 hour later Polymerization was carried out while adding the above mixture at a rate of 10 liters / hour for 9 hours.
After 2 hours, the polymerization was completed to obtain a dispersion liquid of polymer particles. During the polymerization, the temperature inside the reaction vessel could be stably maintained at 75 ° C. The reaction yield in this polymerization was 99%. Then, the above-mentioned dispersion liquid was subjected to steam strip treatment. The obtained polymer particles have a capsule shape, an outer diameter of 0.51 μm and an inner diameter of 0.2.
was μm.

[0075]

Industrial Applicability According to the present invention, there are provided polymer particles having a single inner pore, which are composed of a cross-linked copolymer. The polymer particles are small-sized polymer particles consisting of a cross-linked copolymer that is hollow and has a single inner hole that is surely partitioned from the polymer layer, and therefore has a high mechanical strength and heat resistance. It has excellent characteristics in terms of the above, and is easy to manufacture.

The polymer particles of the present invention can also be obtained as hollow polymer particles having hollow inner pores or water-containing hollow polymer particles having water in the inner pores by removing the oily substance from a single inner pore. It is also possible to obtain capsule-shaped polymer particles in which the internal pores contain an oily substance or another substance.

The hollow polymer particles have peculiar optical performance in terms of particle size and the like, and are excellent in hiding power, whiteness and luster, and are lightweight, highly absorbent,
Various applications as highly oil-absorbing fillers, for example, paints, compounding agents for paper coating compositions, water-absorbing fillers for inkjet paper, internal fillers in the paper manufacturing process, high hiding properties for correction inks or correction ribbons. It can be used as a pigment or the like.

Further, the above-mentioned capsule-shaped polymer particles are characterized in that they are well encapsulated and have excellent mechanical strength and heat resistance. The capsule-shaped polymer particles not only can contain various oil-soluble substances such as a solvent, a plasticizer, a fragrance, an ink, a pesticide, a medicine, and a flavor as an inner core, and further gradually add these substances. It has a sustained-release function of allowing it to be diffused into, and can be used in many fields as a microcapsule material.

[Brief description of drawings]

FIG. 1 is an electron micrograph showing the particle structure of capsule-shaped polymer particles according to an example of the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical display location C08F 265/06 MQM 7142-4J 279/02 MQP 7142-4J C08K 5/00 (72) Inventor Sakurai Nobuo 2-11-24 Tsukiji, Chuo-ku, Tokyo Japan Synthetic Rubber Co., Ltd.

Claims (2)

[Claims] 1. (a) 1 to 50% by weight of a crosslinkable monomer,
A cross-linked copolymer of a polymerizable monomer component consisting of (b) 1 to 99% by weight of a hydrophilic monomer and (c) 0 to 85% by weight of the above-mentioned crosslinkable monomer or other polymerizable monomer copolymerizable with the hydrophilic monomer. 100 parts by weight and a different polymer having a composition different from that of the copolymer 1 to
The cross-linked copolymer has an outer diameter of 0.05-1.
A polymer particle having a single inner hole, wherein a hollow body having a diameter of 0 μm and an inner diameter of 0.2 to 0.95 times the outer diameter is formed. 2. The crosslinkable monomer is at least one selected from divinylbenzene and ethylene glycol dimethacrylate, and the hydrophilic monomer is selected from acrylic acid, methacrylic acid, methyl methacrylate, 2-hydroxyethyl methacrylate and vinyl pyridine. At least one kind, wherein the different polymer is polystyrene, carboxy-modified polystyrene, carboxy-modified styrene butadiene copolymer, styrene butadiene copolymer, styrene acrylic ester copolymer,
At least one selected from styrene methacrylic ester copolymer, acrylic ester copolymer, methacrylic ester copolymer, carboxy-modified styrene acrylic ester copolymer, carboxy-modified styrene methacrylic ester copolymer, carboxy-modified acrylic ester copolymer and carboxy-modified methacrylic ester copolymer. Polymer particles having a single internal pore as described.