JPH07116499A - Microcapsule, microcapsule toner and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve environmental stability of electrification using a microcapsule, excellent in holding performance and mechanical strength of core material. CONSTITUTION:There are provided a process wherein a mixture comprising core material, low boiling-point solvent, and first capsule shell forming monomer is produced by the use of low boiling-point solvent containing ether solvent having a solubility of 1-50g for 100g of water and a process wherein the mixture obtained is emulsified and dispersed in a water medium containing second shell forming monomer to form oil liquid droplets, whereby the low boiling-point solvent is discharged from the oil droplets. And the first shell forming monomer and the second shell forming monomer are polymerized at the interface of the liquid droplets to form a capsule shell. A microcapsule toner is manufactured by attaching electrification controlling polymer to the surface of the capsule shell.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to microcapsules and microcapsule toners that can be used for developing electrostatic latent images in electrophotography, electrostatic printing and the like, and a method for producing them.

[0002]

2. Description of the Related Art Various proposals have heretofore been made for microcapsules comprising a core substance and a capsule shell covering the core substance. Among them, the microcapsules having a capsule shell formed by interfacial polymerization are excellent in the completeness of the coating with respect to the core substance and the internal retention property, and some of them are put to practical use in non-carbon paper and pressure measuring paper.
In these cases, the microcapsule is used in such a form that it is coated on a support such as paper together with a suitable binder resin, and the microcapsule particles are present in the binder resin. However, when microcapsule particles are used as independent powders, the capsules obtained by the interfacial polymerization method have weak mechanical strength, and the capsule shell is usually 0.5 μm or less in thickness. It was difficult to retain the core substance for a long time.

Generally, in the production of interfacial polymerization type microcapsules, a method of using a low boiling point solvent together with a core substance is general. (For example, JP-A-56-119137,
JP-A-58-145964, JP-A-63-163
373 and Japanese Unexamined Patent Publication No. 64-40949, or the Microcapsule Study Group's "New Technology of Microencapsulation and Its Application and Application Examples" p. 50-52:
Business Development Center Publishing Department Published in September 1978; Yasushi Kondo,
Mazumi Koishi "Microcapsules" P. 50-52: Sankyo Publishing, published in November 1987). As the low boiling point solvent used in these methods, an ester solvent such as ethyl acetate or butyl acetate, an aromatic solvent such as toluene or xylene, or a halogen solvent such as dichloromethane or chloroform is used. However, as a result of the research conducted by the present inventors, ester solvents such as ethyl acetate and butyl acetate hydrolyze in the presence of an amine that is a capsule shell-forming monomer to form a salt with the amine. It was found that the formed amine could not contribute to the capsule shell formation. As a result, it was found that the strength of the capsule shell was weak and the retention of the core substance was also reduced. In particular, it was remarkably observed when the temperature of the encapsulation reaction was 20 to 40 ° C. On the other hand, an aromatic solvent such as toluene or xylene or a halogen solvent such as dichloromethane or chloroform is poorly soluble in water and cannot be expelled from the system. There was a problem that it could not move to the droplet interface and, as a result, the capsule shell formation was not sufficient, and that an unnecessary solvent remained in the capsule together with the core substance. Further, JP-A-64-40949 discloses an example using a mixed solvent of acetone and ethyl acetate and a mixed solvent of acetone and halogenated hydrocarbon, but acetone is extremely water-soluble. Since it is high, the emulsification failure is likely to occur, and therefore the capsule shell formation is not sufficient, and ethyl acetate and halogenated hydrocarbon also have the above-mentioned drawbacks.

When the microcapsules are used as a toner, it is more difficult to achieve both mechanical strength and retention of the core substance. Various proposals have heretofore been made for a microcapsule toner including a capsule shell covering a core substance. Regarding the core substance, for example, JP-A-54-66844 and JP-A-55-18.
No. 630, JP-A-57-41647, and JP-A-57-202547 disclose microcapsule toners containing a wax-based compound as a fixing component of a core substance. Publication, JP-A-58
-9153, JP-A-59-159174,
JP-A-59-159177 discloses a microcapsule toner containing a soft polymer as a fixing component of a core substance, and JP-A-56-119137, JP-A-58-145964 and JP-A-58-145964. 63-163373
Japanese Patent Publication discloses a microcapsule toner containing a polymer solution as a fixing component of a core substance. Above all, in the case of the interfacial polymerization type microcapsule toner using the polymer solution as the core substance component, the fixability is extremely good. However, on the other hand, it was difficult to retain the high boiling point solvent contained in the polymer solution in the core substance for a long period of time. It was also difficult to have sufficient mechanical strength without impairing the fixability.

[0005]

SUMMARY OF THE INVENTION The present invention has been made for the purpose of solving the above-mentioned problems in the prior art. That is, an object of the present invention is to provide a microcapsule excellent in retention performance and mechanical strength of a core substance even if the microcapsule is used as a powder, and a method for producing the same. Another object of the present invention is to provide a microcapsule toner for electrophotography which has good environmental stability of charging. Still another object of the present invention is to
It does not impair the fixing performance that the core material should have, has excellent mechanical strength, does not require a special reaction device or complicated operation,
Provided is a method for producing a microcapsule toner which can be applied to a capsule toner in which a core substance is liquid.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that in a method for producing microcapsules, which is produced by interfacial polymerization using a low boiling point solvent together with a core substance,
The inventors have found that the above object can be achieved by using an ether solvent having a solubility in 100 g of water of 50 g or less as a low boiling point solvent, and have completed the present invention.

That is, the first aspect of the present invention relates to a microcapsule consisting of a core substance and a capsule shell, which contains a core substance and an ether solvent having a solubility of 1 to 50 g in 100 g of water. Boiling point solvent, and first
The mixture of the capsule shell-forming monomers of (1) is emulsified and dispersed in an aqueous medium containing the second shell-forming monomer to expel the low boiling point solvent from the formed oily droplets to the outside of the system, It has a capsule shell formed by polymerizing the first shell-forming monomer and the second shell-forming monomer at the interface. In addition, in this specification, the solubility in water means the thing in 20 degreeC. Second of the present invention
Relates to a microcapsule toner comprising a core substance and a capsule shell, which comprises a core substance, a low boiling point solvent containing an ether solvent having a solubility in 100 g of water of 1 to 50 g, and a first capsule shell. The mixture of the forming monomers is emulsified and dispersed in an aqueous medium containing the second shell forming monomer to expel the low boiling point solvent from the formed oily droplets to the outside of the system, and at the interface of the droplets. It has a capsule shell formed by polymerizing the first shell-forming monomer and the second shell-forming monomer, and the charge control polymer is attached to the surface of the capsule shell. And

A third aspect of the present invention relates to a method for producing microcapsules, which has a solubility in 100 g of water in a method for producing microcapsules produced by interfacial polymerization using a low boiling point solvent together with a core substance. 1-5
A step of preparing a mixture of a core substance, a low boiling point solvent and a first capsule shell forming monomer using a low boiling point solvent containing 0 g of an ether solvent, and the obtained mixture is used to form a second shell A step of emulsifying and dispersing in an aqueous medium containing a monomer to form oily droplets, and expelling the low boiling point solvent from the oily droplets to the outside of the system, and at the interface of the droplets, the first shell-forming monomer And a second shell-forming monomer to polymerize to form a capsule shell. A fourth aspect of the present invention relates to a method for producing a microcapsule toner, which has a solubility in 100 g of water in the method for producing a microcapsule produced by interfacial polymerization using a low boiling point solvent together with a core substance. 1
A step of preparing a mixture of the core substance, the low boiling point solvent and the first capsule shell forming monomer using a low boiling point solvent containing an ether solvent in an amount of ˜50 g; A step of emulsifying and dispersing in an aqueous medium containing a forming monomer to form oily droplets, expelling the low boiling point solvent from the oily droplets to the outside of the system, and at the interface of the droplets a first shell forming monomer And a second shell-forming monomer to form a capsule shell, and a step of attaching a charge controllable polymer to the surface of the capsule shell.

The present invention will be described in detail below. The microcapsules and microcapsule toners used in the present invention are produced by a so-called interfacial polymerization method. The method for producing microcapsules by the interfacial polymerization method is described in, for example, Japanese Patent Publication No. 38-19574 and No. 42-4.
46, Japanese Patent Publication No. 2-31381, JP-A-58
As disclosed in JP-A-66948, JP-A-59-148066, and JP-A-59-162562, the first capsule shell-forming monomer present in oily droplets and the first capsule shell-forming monomer present in an aqueous solvent are disclosed. In this method, the capsule shell forming monomer (2) is reacted at the interface of the oily droplets to form a capsule shell.

In the interfacial polymerization method of the present invention, first, in a first step, a mixture of a core substance, a low boiling point solvent and a first capsule shell forming monomer is prepared.
In the present invention, the core substance is not particularly limited, and various active substances can be used as the core substance component as long as it is poorly soluble in water or oil-soluble depending on the application. When microcapsules are used as capsule toners, when the purpose is pressure fixing, a core substance mainly composed of a component having pressure fixing property is used, and when the purpose is heat fixing, heat fixing is used. A core substance mainly composed of a component having properties is used. Particularly for the purpose of pressure fixing, it is preferable that the core substance is mainly composed of a binder resin and a high-boiling-point solvent that dissolves the binder resin and a coloring material, or that is mainly composed of a soft solid substance and a coloring material. If necessary, a magnetic powder may be added in place of the coloring material, or an additive such as silicone oil may be added for the purpose of improving fixability. Further, a high boiling point solvent which does not dissolve the binder resin can be added to the high boiling point solvent which dissolves the binder resin. It is desirable to change the kinds or composition ratios of the constituents depending on whether the purpose is pressure fixing or heat fixing.

As the binder resin, a known fixing resin can be used. Specifically, acrylic acid ester polymers such as polymethyl acrylate, polyethyl acrylate, butyl polyacrylate, 2-ethylhexyl polyacrylate, and lauryl polyacrylate, polymethyl methacrylate, polybutyl methacrylate, poly Hexyl methacrylate, 2-ethylhexyl polymethacrylate,
Methacrylic acid ester polymers such as polylauryl methacrylate, copolymers of styrene-based monomers and acrylic acid esters or methacrylic acid esters, ethylene-based polymers such as polyvinyl acetate, vinyl polypropionate, polyvinyl butyrate, polyethylene and polypropylene. Polymers and their copolymers, styrene / butadiene copolymers, styrene / isoprene copolymers, styrene / styrene copolymers such as styrene / maleic acid copolymers, polyvinyl ethers, polyvinyl ketones, polyesters, polyamides, polyurethanes, rubbers , Epoxy resin, polyvinyl butyral, rosin, modified rosin, terpene resin, phenol resin and the like, and these can be used alone or in combination. It is also possible to prepare a binder resin by polymerizing after charging and encapsulation in a monomer state.

As the high boiling point solvent for dissolving the binder resin, an oily solvent having a boiling point of 140 ° C. or higher, preferably 160 ° C. or higher can be used. For example, Modeler
nPlastics Encyclopedia (19
75 to 1976) and those described in Plasticizers can be selected. Further, it has been disclosed as a core substance of a pressure fixing capsule toner (for example, JP-A-58-145964, 63-1633).
No. 73, etc.) It is also possible to select from high boiling point solvents.

Specifically, phthalic acid esters (eg, diethyl phthalate, dibutyl phthalate); aliphatic dicarboxylic acid esters (eg, diethyl malonate, dimethyl oxalate); phosphoric acid esters (eg, tricresyl) Phosphate, trixylyl phosphate); Citric acid esters (eg, O-acetyltriethyl citrate); Benzoic acid esters (eg, butyl benzoate, hexyl benzoate); Fatty acid esters (eg, hexadecyl myristate, dioctyl adipate) Alkylnaphthalenes (eg, methylnaphthalene, dimethylnaphthalene, monoisopropylnaphthalene, diisopropylnaphthalene); alkyldiphenyl ethers (eg, o-,
m-, p-methyldiphenyl ether); amide compounds of higher fatty acid or aromatic sulfonic acid (eg, N, N-
Dimethyllaurylamide, N-butylbenzenesulfonamide); trimellitic acid esters (eg, trioctyl trimellitate); diarylalkanes (eg, diarylmethane such as dimethyldiphenylmethane, 1-phenyl-1-methylphenylethane) , 1-dimethylphenyl-1-phenylethane, 1-ethylphenyl-1-phenylethane, etc.); and chlorinated paraffins. When a polymer having a long-chain alkyl group such as lauryl methacrylate homopolymer or copolymer is used as the binder resin, an aliphatic saturated hydrocarbon or an organic solvent containing an aliphatic saturated hydrocarbon as a main component (for example, Exxon Chemical Made by Isopa
r-G, Isopar-H, Isopar-M, etc.) can be used.

Examples of the coloring material include inorganic pigments such as carbon black, red iron oxide, navy blue, titanium oxide, fast yellow, disazo yellow, pyrazolone red, chelate red, azo pigments such as brilliant carmine and para brown, copper phthalocyanine and metal-free phthalocyanine. And condensed polycyclic pigments such as flavantron yellow, dibromoanthrone orange, perylene red, quinacridone red, and dioxazine violet. Further, disperse dyes, oil-soluble dyes and the like can also be used.

Furthermore, as the magnetic one-component toner, all or part of the black coloring material can be replaced with magnetic powder. As the magnetic powder, magnetite, ferrite, a simple metal such as cobalt, iron, nickel, or an alloy thereof can be used. Furthermore, the coloring material or magnetic powder charged as one component of the core substance may be present at the interface between the core and the outer shell or in the outer shell after capsule formation.

The soft solid substance is not particularly limited as long as it has flexibility and fixability at room temperature, but a polymer having a Tg in the range of -60 ° C to 5 ° C or its weight is preferable. Mixtures of coalesce and other polymers are preferred. As a method of incorporating the binder resin or the soft solid substance into the capsule as one component in the core substance, a polymer is preliminarily charged with other core substance components, a low boiling point solvent and an outer shell forming component, and interfacial polymerization is carried out. It is possible to use a method of forming a core substance by ejecting the low boiling point solvent out of the system at the same time as forming the outer shell with or after forming the outer shell.
Alternatively, a method may be used in which the core is formed by polymerizing the monomer after forming the outer shell by interfacial polymerization prepared in the monomer state.

Next, the low boiling point solvent which is one of the features of the present invention will be described. The low boiling point solvent referred to here is 1.
The boiling point at 0 × 10 ⁶ Pa (760 mmHg) is 12
The mixture is charged with a solvent at 0 ° C. or lower, preferably 100 ° C. or lower, as a component of the capsule raw material, mixed with the core substance and the first capsule shell-forming monomer, and the system is used during or after the emulsification and encapsulation reaction. It will be removed to the outside. The role of this low boiling point solvent is not only the effect as a diluent for lowering the viscosity of the core substance to facilitate emulsification, but also effectively moves the first capsule shell forming monomer to the droplet interface, It also has the effect of promoting the reaction with the capsule shell forming monomer (2). In the present invention, the low boiling point solvent has a solubility in 100 g of water of 1 to 5 at 20 ° C.
It is characterized by using an ether solvent in the range of 0 g, preferably in the range of 1 to 30 g. When the solubility in water is lower than 1 g, shell formation is insufficient and the solvent remains in the capsule. If it exceeds 50 g, emulsification becomes difficult.

Specific examples of ether solvents that can be used in the present invention include diethyl ether (solubility in water, the same applies hereinafter: 7.0) and furan (1.
0), tetrahydropyran (8.7), diethoxyethane (26.6), methylal (47.7) and acetal (5.3). Among them, diethyl ether, furan, and tetrahydropyran have a boiling point of 100 ° C. or less, and are particularly preferable because they are easily removed to the outside of the system. Particularly, since diethyl ether has a low boiling point of 35 ° C. and high volatility, when it is used, it has an advantage that the polymerization reaction can be carried out at room temperature. The ether solvent may be used as a mixture with other solvent, for example, ester solvent, aromatic solvent or halogen solvent.
In particular, when polyisocyanates are used as the first capsule shell-forming monomer, the capsule shell-forming monomer is often diluted with a small amount of a solvent such as ethyl acetate in advance and commercially available. Therefore, it is more convenient to use the above mixed solvent system. When mixed with another solvent, the content of the above ether solvent is preferably 50% by weight or more, and more preferably 60% by weight or more based on the total amount of the solvent.

In the present invention, examples of the first capsule shell forming monomer mixed with the core substance and the low boiling point solvent include an isocyanate compound, an acid halide and an epoxy compound. Specifically, as the isocyanate compound, metaphenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, 3,
3'-dimethyl-diphenyl-4,4'-diisocyanate, 3,3'-dimethyl-diphenylmethane-4,
Diisocyanates such as 4'-diisocyanate, xylylene diisocyanate, naphthalene diisocyanate and hexamethylene diisocyanate, or polyisocyanates known as so-called burette type, adduct type and isocyanurate type are available. Can be mentioned. For example, polyisocyanates that are commercially available as Sumidure series manufactured by Sumitomo Bayer Urethane Co., Takenate series manufactured by Takeda Pharmaceutical Co., Ltd., and Millionate series manufactured by Nippon Polyurethane Industry Co., Ltd. are preferably used. Acid halides include adipoyl dichloride, phthaloyl dichloride, terephthaloyl dichloride, 1,4
-Dibasic acid halides such as cyclohexanedicarbonyl chloride. As an epoxy compound,
Bisphenol A type, resorcin type, bisphenol F
Examples thereof include epoxy compounds known as type, tetraphenylmethane type, novolac type, polyalcohol type, polyglycol type, and glycerin triether type. Among them, when the microcapsules are applied to the toner, it is preferable that at least an isocyanate is contained from the viewpoint of electrical resistance. Among them, polyisocyanates are particularly preferable. A more preferred embodiment is to use polyisocyanates which are soluble in a low boiling point solvent and which are in a suspended state without being completely dissolved in a mixed solution of the core substance and the low boiling point solvent. The reason is that, under such a condition, the first capsule shell-forming monomer is smoothly moved to the droplet interface, and as a result, encapsulation, that is, shell formation, proceeds efficiently. .

In the present invention, in the next step, the mixture obtained by mixing the above components is emulsified and dispersed in an aqueous medium containing the second shell-forming monomer to form oily droplets. To do. The second capsule shell forming monomer reacts with the first capsule shell forming monomer to form a polymer, and specifically, water, ethylene glycol, 1,4-butanediol. , Catechol, resorcinol, hydroquinone, o-dihydroxymethylbenzene, 4,4'-
Polyhydroxyl such as dihydroxydiphenylmethane, 2,2-bis (4-hydroxyphenyl) -propane or polyamine such as ethylenediamine, tetramethylenediamine, hexamethylenediamine, phenylenediamine, diethylenetriamine, triethylenetetramine, diethylaminopropylamine, tetraethylenepentamine ,
Alternatively, piperazine-based compounds such as piperazine, 2-methylpiperazine, and 2,5-dimethylpiperazine can be used. These can also be mixed and used. A particularly preferred embodiment is one containing isocyanate as the first capsule shell-forming monomer and encapsulating with water and polyamine as the second capsule shell-forming monomer.
Of the above-mentioned second capsule shell-forming monomers, the polyols can be charged into the oily droplets together with the first capsule shell-forming monomer. Water or a hydrophilic substance such as alcohol may be added to the aqueous medium, if necessary. Further, a dispersant such as cellulose can be used. When polyamine is added, a part of it may be mixed in advance with the aqueous medium before emulsification.

The oily liquid droplets formed by the above-mentioned step then drive the low boiling point solvent out of the system from the oily liquid droplets, and at the interface of the liquid droplets, the above-mentioned first shell-forming monomer and the above-mentioned second shell-forming monomer. The shell forming monomer is polymerized. By this step, a capsule shell is formed, and a desired microcapsule can be manufactured.

Further, in the present invention, when the microcapsule toner is manufactured, the charge control polymer is further attached to the capsule shell formed by the above steps. The charge control polymer attached to the capsule shell will be described. The attachment of the charge control polymer to the capsule shell may be physical attachment or chemical attachment. The charge controllable polymer means a polymer capable of imparting a positive charging property or a negative charging property to a toner by contact or friction with a charging member.
Specifically, in the case of imparting positive chargeability, a nitrogen-containing polymer such as a polymer having an amino group, a pyridyl group, a dialkylamino group or a quaternary ammonium salt structure can be used. In the case of imparting negative chargeability, a polymer having a carboxyl group, a sulfonic acid group, a group having a salt structure thereof, or a fluorinated alkyl group can be used. Alternatively, it may be a compound known as a conventional charge control agent, for example, a compound itself such as a nigrosine dye, a chrome-containing chromium dye or a phthalocyanine dye, or a polymer containing a similar substance. Of these, polymers having a dialkylamino group or a group having a quaternary ammonium salt structure, a carboxyl group, and a fluorinated alkyl group are particularly preferable in terms of charging stability and manufacturability.

As the quaternary ammonium salt-containing vinyl monomer, which is one of the monomer components constituting the charge control polymer, there may be mentioned those represented by the following general formula (I).

[Chemical 1] (In the formula, R ₁ represents a hydrogen atom or a methyl group, and R ₂
To R ₄ each represent an alkyl group having 1 to 8 carbon atoms or an aralkyl group, Y represents —COO—, —CONH— or a phenylene group, and n represents an integer of 1 to 8,
X ⁻ represents an anion. )

In the above general formula (I), compounds (1) to (6) represented by the following structural formulas can be mentioned as the cation moiety.

[Chemical 2]

Further, as the anion: X ⁻ , those represented by the following structural formula can be mentioned. Cl ^-, Br ^-, I ^-
Halogen ion such as CH ₃ COO ⁻ , C _{2
^{H 5 COO -, C 3 H}} 7 COO -, C 7 H 15 COO -,
An aliphatic carboxylic acid group such as C ₁₁ H ₂₃ COO ⁻ ,

[0026]

[Chemical 3] Aromatic carboxylic acid groups of an equal or CH ₃ SO _3, ^-, C
^{_{2 H 5 SO 3 -, C}} 3 H 7 SO 3 -, C 7 H 15 S
Aliphatic sulfonic acid groups such as O ₃ ⁻ , C ₁₁ H ₂₃ SO ₃ ⁻ ,

[0027]

[Chemical 4] And other aromatic sulfonic acid groups. Alternatively, it may be an anion residue of an acid dye such as acid red, acid orange, acid violet or acid blue.

In the present invention, the monomer represented by the general formula (I) may be in the form of a homopolymer or may be present as one component of a copolymer. When present as one component of the copolymer, the content of the above monomer is preferably 1 mol% to 80 mol%, and more preferably 5 mol% to 60 mol% based on the total copolymerization.

Examples of the monomer copolymerizable with the monomer represented by the general formula (I) include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, Butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) acrylic acid 2
-Ethylhexyl, benzyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, glycidyl (meth) acrylate, phenyl (meth) acrylate, etc. (Meth) acrylic acid esters, vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl trimethyl acetate, vinyl caproate, vinyl caprylate, vinyl stearate, and other fatty acid vinyl esters, or ethyl vinyl ether, propyl vinyl ether , Butyl vinyl ether, hexyl vinyl ether, 2-ethylhexyl vinyl ether, phenyl vinyl ether, and other vinyl ethers; methyl vinyl ketone, phenyl vinyl ketone, and other vinyl ketones; styrene; Rusuchiren, hydroxystyrene,
Examples thereof include vinyl aromatic compounds such as α-methylstyrene. One or two or more of these may be mixed and copolymerized with the monomer (I).
Among these, (meth) acrylic acid esters are particularly preferable.

[0030]

【Example】

Example 1 (Preparation of Microcapsules) Saturated aliphatic hydrocarbon (Is
oper-M: manufactured by Exxon Co.) 60 g and a mixed solution of diethyl ether (solubility in water 7.0) 80 g, 30 g of lauryl methacrylate polymer (Mw = 3 × 10 ⁴ ) and lauryl methacrylate / n-butyl methacrylate copolymer. 40 g of (Mw = 6 × 10 ⁴ ) was added and dissolved. Magnetic powder (EPT-1000: manufactured by Toda Kogyo Co., Ltd.) 120g
Was added and dispersed in a sand mill for 16 hours. Next, an isocyanate (Takenate D1) was added to 200 g of this dispersion.
40 g of 10N: Takeda Yakuhin Kogyo Co., Ltd. was added and mixed thoroughly (this liquid is referred to as liquid A). On the other hand, 200 deionized water
Dissolve 10 g of hydroxypropylmethyl cellulose (Metroses 65SH50: manufactured by Shin-Etsu Chemical Co., Ltd.) in 5 g, and 5 ° C.
It cooled to this (this liquid is set to B liquid). The liquid B was stirred with an emulsifying machine (auto homomixer: manufactured by Tokushu Kiki Co., Ltd.), and the liquid A was slowly added to the liquid for emulsification. Thus, an O / W emulsion in which the average particle size of the oil droplet particles in the emulsion was about 12 μm was obtained. Next, the emulsifier was replaced with a stirrer equipped with a propeller-type stirring blade (Three One Motor: manufactured by Shinto Kagaku Co., Ltd.), and stirring was performed at 400 rpm. After 10 minutes, 200 g of a 5% diethylenetriamine aqueous solution was added dropwise thereto. After completion of the dropping, the encapsulation reaction was carried out at 25 ° C. for 5 hours while exhausting diethyl ether dissolved in the aqueous phase. After completion of the reaction, the reaction mixture was poured into 2 liters of ion-exchanged water, sufficiently stirred and allowed to stand. After the capsule particles settled, the supernatant was removed. This operation was repeated seven more times to wash the capsule particles. The obtained capsule suspension was opened in a stainless steel vat and dried at 80 ° C. for 24 hours with a dryer (manufactured by Yamato Scientific Co., Ltd.). Thus, the microcapsules of the present invention were obtained. A part of this microcapsule was taken out and subjected to a heat treatment at 100 ° C. for 24 hours, and the transpiration amount of Isopar M in the microcapsule was examined. As a result, about 98% of Isopar M originally contained in the capsule was preserved. It was confirmed. Moreover, when the microcapsules were pressed and the destruction rate was examined, it was 10% at 98 N // cm ² (10 kgf / cm ² ).
Met. From these results, it was found that the microcapsules of the present invention are excellent in core material retention performance and mechanical strength.

Example 2 (Tonerization) Capsule particles prepared in exactly the same manner as in Example 1 were prepared into a suspension having a solid content concentration of 40%, and 125 g of this liquid (corresponding to 50 g of capsule particles) was added to the suspension. Add 125 g of ion-exchanged water and use a stirrer (three-one motor: manufactured by Shinto Kagaku Co., Ltd.) equipped with a propeller-type stirring blade for 200
Stirred at rev / min. After adding 5 g of 1N nitric acid and 4 g of a 10% aqueous cerium sulfate solution, 0.5 g of ethylene glycol dimethacrylate was added and the reaction was carried out at 15 ° C. for 3 hours. After completion of the reaction, the mixture was poured into 1 liter of ion-exchanged water, sufficiently stirred and allowed to stand. After the capsule particles settled, the supernatant was removed. This operation was repeated twice more to wash the capsule particles. In this way, capsule particles in which ethylene glycol dimethacrylate was graft-polymerized on the surface of the capsule shell were obtained.

This was resuspended in ion-exchanged water again, and a stirrer equipped with a propeller-type stirring blade (three-one motor:
Stirring was performed at 200 revolutions / minute by Shinto Kagaku. Next, 0.4 g of potassium persulfate, 0.2 g of chloride of the exemplified compound (1), 2.0 g of methyl methacrylate and 0.16 g of sodium hydrogen sulfite were sequentially added thereto, and the mixture was added at 25 ° C. for 3 hours. The reaction was carried out over time. After completion of the reaction, the mixture was poured into 2 liters of ion-exchanged water, sufficiently stirred and allowed to stand. After the capsule particles settled, the supernatant was removed. This operation was repeated four more times to wash the capsule particles.

Next, 2 g of a 5% aqueous solution of sodium 4-naphtholsulfonate was added to this capsule particle suspension, and
Ion exchange reaction was performed by stirring at room temperature for a minute. After the reaction was completed, the capsule particles were washed 5 times with 1 liter of ion-exchanged water to obtain the microcapsule toner of the present invention. The obtained capsule suspension was opened in a stainless vat and dried at 60 ° C. for 10 hours with a dryer (Yamato Scientific Co., Ltd.). To 100 parts of the obtained microcapsule toner, basic carbon black (pH value 8.5) (REGAL330
R: made by Cabot Co.) was added to 0.1 part and mixed well.

The image quality of the obtained microcapsule toner was evaluated in an environment of a temperature of 20 ° C. and a humidity of 50%. The copying machine used was a Fuji Xerox 2700 modified for capsule toner. As a result, up to the 5000th sheet, a stable copy with no image quality defect was obtained. Also,
No phenomenon that the toner was crushed and adhered to the toner supply roll and the photoconductor was observed.

Example 3 In Example 1, 60 g of tetrahydropyran (solubility 8.7) was used in place of 80 g of diethyl ether, and the encapsulation reaction was carried out at 60 ° C. for 3 hours to prepare the microcapsules of the present invention in the same manner. . A part of this microcapsule was taken out and subjected to heat treatment at 100 ° C. for 24 hours to examine the amount of transpiration of Isopar M in the microcapsule. It was confirmed that about 98% of Isopar M originally contained in the microcapsule was preserved. Was confirmed. Also, when the microcapsules were pressed and the destruction rate was examined, it was 98 N
It was 9% at // cm ² (10 kgf / cm ² ). From this result, it was found that the microcapsules were excellent in core material retention performance and mechanical strength.

Comparative Example 1 In place of 80 g of diethyl ether in Example 1, 60 g of ethyl acetate (solubility 8.8) was used to prepare microcapsules for comparison in the same manner. A part of this microcapsule was taken out and heat-treated at 100 ° C. for 24 hours, and the amount of Isopar M evaporated in the microcapsule was examined. As a result, about 50% of Isopar M originally contained in the microcapsule disappeared. Further, when the destruction rate was examined by pressurizing the capsule particles, 98 N // cm ² (10
It was 30% in kgf / cm ² . From these results, it was found that the microcapsules were inferior in the core material retention performance and mechanical strength.

Comparative Example 2 Next, the microcapsules produced in Comparative Example 1 were made into toner in the same manner as in Example 2. The image quality of the obtained microcapsule toner was evaluated under the environment of temperature of 20 ° C. and humidity of 50% in the same manner as in Example 2. From the 300th sheet, the crushed toner began to adhere to the surface of the toner supply roll. .
From the 500th sheet, countless white streaks were generated on the copy and the image quality was remarkably inferior. When the surface of the photoconductor was examined, it was found that the microcapsule toner was crushed and adhered.

Comparative Example 3 In place of 80 g of diethyl ether used in Example 1, 80 g of tetrahydrofuran having a solubility in water of more than 50 was used to prepare microcapsules in the same manner.
Due to poor emulsification, a satisfactory capsule could not be obtained.

[0039]

As described above, the method for producing a microcapsule and a microcapsule toner of the present invention uses 100 g of water as a solvent for dissolving or dispersing the core substance.
A low boiling point solvent containing an ethereal solvent with a solubility of 1 to 50 g is used to form a capsule shell by interfacial polymerization, so it does not impair the fixing performance that the core material should have and is excellent in mechanical strength. , Does not require special reaction equipment or complicated operation. It can also be applied to the production of capsule toner in which the core substance is liquid. The formed microcapsules and microcapsule toners are excellent in core material retention performance and mechanical strength. In addition, the microcapsule toner has good environmental stability of charging and is excellent as a toner for electrophotography.

Claims (4)

[Claims] 1. The core substance has a solubility of 1 to 5 in 100 g of water.
A mixture of a low boiling point solvent containing 0 g of an ether solvent and a first capsule shell forming monomer was added to the second
Emulsified and dispersed in an aqueous medium containing the shell-forming monomer to expel the low boiling point solvent from the formed oily droplets to the outside of the system, and at the interface of the droplets, the first shell-forming monomer and the second shell-forming monomer A microcapsule comprising a core material and a capsule shell, which has a capsule shell formed by polymerizing with a shell-forming monomer. 2. The core substance has a solubility of 1 to 5 in 100 g of water.
A mixture of a low boiling point solvent containing 0 g of an ether solvent and a first capsule shell forming monomer was added to the second
Emulsified and dispersed in an aqueous medium containing the shell-forming monomer to expel the low boiling point solvent from the formed oily droplets to the outside of the system, and at the interface of the droplets, the first shell-forming monomer and the second shell-forming monomer A microcapsule comprising a core substance and a capsule shell, which has a capsule shell formed by polymerizing with a shell-forming monomer, and a charge control polymer is attached to the surface of the capsule shell. toner. 3. A method for producing microcapsules produced by interfacial polymerization using a low boiling point solvent together with a core substance, wherein a low boiling point solvent containing an ether solvent having a solubility in 100 g of water of 1 to 50 g is used, A step of preparing a mixture comprising a core substance, a low boiling point solvent and a first capsule shell-forming monomer, the mixture being emulsified and dispersed in an aqueous medium containing a second shell-forming monomer to form oily droplets. The step of forming, and the low boiling point solvent is expelled from the oily droplet to the outside of the system, and the capsule shell is formed by polymerizing the first shell-forming monomer and the second shell-forming monomer at the droplet interface. A method for producing a microcapsule, which comprises the step of forming. 4. A method for producing a microcapsule produced by interfacial polymerization using a low boiling point solvent together with a core substance, wherein a low boiling point solvent containing an ether solvent having a solubility in 100 g of water of 1 to 50 g is used, A step of preparing a mixture comprising a core substance, a low boiling point solvent and a first capsule shell-forming monomer, the mixture being emulsified and dispersed in an aqueous medium containing a second shell-forming monomer to form oily droplets. Forming step, a low boiling point solvent is expelled from the oily droplet to the outside of the system, and a capsule shell is formed by polymerizing the first shell-forming monomer and the second shell-forming monomer at the droplet interface. And a step of adhering a charge controllable polymer to the surface of the capsule shell.