JPS58216736A - Microencapsulated particles - Google Patents

Abstract

PURPOSE:To uniformize diameters of microcapsules, by continuously executing a step of forming a core material and that of microencapsulating it. CONSTITUTION:A colorant, a magnetic powder, a hardening agent, etc. are added to a polyester, polyamide, or epoxy resin, or the like by <=80wt% of the resin to obtain the core material. As a shell material, polystyrene, polymonochlorostyrene, and styrene-methacylate copolymer are embodied. These core material and shell material as well as a magnetic powder, etc. are kneaded with a mixer. The obtd. melt is fed to a bell by using a constant feed rategear pump provided with a heating kettle and a heating tube. A solution obtd. by dissolving this mixture in a solvent such as DMF is fed to the face to be coated. The microcapsules obtained are collected and dried after filtration to obtain microencapsulated particles.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to microcapsule particles having a uniform particle size distribution manufactured using an electroemulsification method. It is a container that utilizes functions such as protecting contents and controlling the release of contents, and is currently being commercialized as carbonless close-up paper, fast-acting and slow-acting drugs/catalysts, and rust preventive agents. In terms of utility value, these are only a part of the field, and future developments are expected.

In order to microcapsule a conventional substance, it is first necessary to perform a dispersion emulsification process (first step) in which the subsequent substance is divided into small particles, and an encapsulation process (second step) in which a coating is placed on top of the dispersion emulsification process. For example, to make uniform microcapsule particles, the core material is uniformly atomized by using a large amount of emulsifier in advance, high-speed mechanical stirring, ultrasonic vibration, etc. Or, in the state until -t, a substance that will become a wall film is fixed in a dispersion medium containing a core substance, and a wall film is formed using an interfacial polymerization method, a phase separation method, or a cooling method as necessary, In some cases, methods are used to further strengthen the capsule wall chemically or physically to form a stable wall. However, in the conventional law, the first
The essential condition of using a large amount of emulsifier in the process causes the emulsifier to remain on the surface layer of the core material in the second step, resulting in a significant decrease in the adhesive force between the core material and the wall film during microencapsulation. At the same time, single particles generated only from the wall substance are produced as by-products, so that it is difficult to obtain microcapsule particles with desired uniform particle size and good so-called monodispersity. Furthermore, the expression of expected functions is adversely affected. For this reason, before the microencapsulation step, the atomized core material is generally pretreated by washing with water or by removing the emulsifier using electrodialysis, a semipermeable membrane, an ion exchange resin, or the like.

However, microencapsulated particles produced using this method suffer from a decrease in yield and a rise in manufacturing costs due to the complexity of the working process, and there are many difficulties and problems in its implementation.

As a result of intensive research in view of the existing problems, the present inventors have overcome the above-mentioned problems by a method that was completely unthinkable in conventional traps. That is, the present invention provides microcapsule particles having a uniform particle size using an electroemulsification method.

An object of the present invention is to provide microcapsule particles having a uniform particle size that are produced by continuously performing a first step of producing a core material and a second step of microencapsulating.

Its characteristic feature is that when voltage is applied, it consists of a first step of forming a core material and a second step of forming a shell, and the first and second steps are carried out virtually continuously. Microcapsule particles manufactured by KotoK.

Fine particles having a uniform particle size obtained by the electroemulsification method as described above are supplied into a medium containing a shell material forming a uniform thin film without directly producing a defective film, so that they appear to be upper microcapsules. Particles are produced continuously. Furthermore, in the present invention, by applying a voltage K, it is possible to prevent the material from flying up and obtain microcapsule particles with a high yield.

In a specific embodiment of the present invention, a high positive or negative voltage is applied to the core material under conditions where the amount of emulsifier is much smaller or not present at all during core formation, and at the same time, mechanical This is carried out by transferring uniformly atomized droplets into a grounded wall material or a dispersion medium containing the wall material while the core material is made to fly in an electric field. As a result, microcapsule particles are obtained in which little or no emulsifier is present in the resulting microcapsule particles.

As the core material used in the present invention, any material that can be ejected into a medium containing shell material using a nozzle or bell while applying a voltage can be used. In general, substances that exhibit a liquid or suspended dispersion state upon discharge are effective, such as polyester 4tJJlWit'9 ester-based urethane polymer; polyester-based alkyd resin; polycaprolactone trimellitic acid ester, rosin ester , modified rosin ester.

Various modified polyester resins represented by the reaction product of isopropylidene phenoxyflobanol and adipic acid, the reaction product of isopropylidene phenoxyflobanol and sebacic acid, etc.; polyethylene wax, carnauba wax, castor wax, rice wax, Schluck wax , Zazol wax, amide wax, montan wax, microcrystalline wax.

Waxes represented by ceresin wax, paraffin wax, and osikerite; behenic acid amide, stearic acid amide, palmitic acid amide, lauric acid amide,
Erucic acid amide, plaidic acid amide, oleic acid amide, elaidic acid amide, metele/bisbehenic acid amide.

Methylenebisstearamide, methylenebisoleicamide, hexamethylenebisstearamide,
Hexamethylene bisoleic acid amide, octamethylene biserucic acid amide.

Monoalkylolamides, polyamides produced from dimerized linoleic acid and diamines and polyamines, polyamide resins represented by reaction products of dicarboxylic acids and linear diamines; polyvinyl acetate, ethylene-vinyl acetate copolymer Examples include polyisobutylene, polystyrene, dodecyl acrylate-styrene copolymer, polyurethane distomer, epoxy resin, epoxidized phenol formaldehyde resin, and acrylic resin. The above resins can be used alone or in some cases as a mixture. This is also the core material; in a molten state or a dispersed state,
In order to be atomized, it must have a sufficiently low melt viscosity.
In general, those having a softening temperature of about 5 to 200°C, particularly preferably about 30 to 150°C, are preferred.

Furthermore, additives such as magnetic powder, coloring pigments, dyes, water-miscible solvents, charge control agents, curing agents, flow regulators, stabilizers, and the like may be dispersed or dissolved in the above resin.

- All known dyes and pigments can be used as colorants, such as carbon black, iron black, nigrosine, benzidine yellow, and quinacridone.

Rhodamine B has a phthalocyanine blue effect. The amount of pigment added is appropriately adjusted depending on the type of pigment used and the degree of coloring. Usually, in order to reduce the viscosity of window materials, the amount of pigment added is 800% by weight or less based on the resin, preferably ij near
It is added in an amount of less than 0% by weight, particularly preferably from 30 to 60%.

The magnetic powder can be any material that becomes magnetized when placed in a magnetic field, typically iron.

Contains powder of ferromagnetic metals such as cobalt and nickel, or compounds such as magnetite, hematite, and ferrite.The content of this magnetic powder is 10 to 8% based on the weight of the core material.
It is used in an amount of 0% by weight, preferably 30 to 60% by weight.

Other core materials used in the present invention include corn oil, castor oil, mineral oil, fats and oils represented by cod liver oil, fragrances, rust preventives, liquid crystal substances, vitamins, minerals and nutrients, pharmaceuticals, polytetrafluoro↓tyrene, etc. Typical lubricants include dicyclohexysiphthale-1m and plasticizers. The additives used vary greatly depending on the purpose of use, but are generally 20 to 200% by weight, preferably 25% by weight.
~100% by weight. If too many additives are used during grain preparation, the viscosity will become too high, making it difficult to pulverize by spraying.
Further, there is a problem that the pumping pressure is too high. The above substances are used by adding a solvent or heating as necessary.

The shell material used in the present invention exhibits a room-temperature soaked body,
In addition, anything soluble or dispersible in water and organic and inorganic solvents can be used.

Furthermore, a portion of the shell material used in the present invention can be added to the base material.

Examples of shell materials include polystyrene.

Polymonochlorostyrene, styrene-methacrylate copolymer, styrene-acrylate copolymer, styrene-maleic acid copolymer, polycarbonate, polyether 1. Low molecular needle polyethylene, polyester, fumarate polyester resin, methyl acrylate-methacrylic acid copolymer, polyamide, gelatin, polypropylene.

polyurethane, epoxy resin, polyvinyl alcohol,
Rosin, ethyl cellulose, paraffin, carboxymethyl cellulose, shellac.

gum arabic, tristearin, polyacrylamide,
Polybutadiene, polyisoprene, silicone resin, polyvinyl chloride, polyvinyl acetate.

Vinyl chloride-vinyl acetate copolymer. Benzyl cellulose, cellulose, acetobutyrate, 5-ethyl-2-vinylpyridine-methyl acrylate-methacrylic acid copolymer, 2-methyl-5-vinylpyridine-methacrylic acid copolymer, vinylpyridine-styrene copolymer , polyvinylpyrrolidone, vinylpyrrolidone-vinyl acetate copolymer, aromatic dicarboxylic acid halides such as phthalic acid chloride, phthalic acid bromide, terephthalic acid bromide, terephthalic acid bromide, ethylenediamine,
Examples include polyamines represented by diethylenetriamine and triethylenetetramine. The above-mentioned compound is supplied onto the surface of the device as it is, or as a copolymer, or in some cases as a mixture, solubilized or dispersed in water and an aqueous or inorganic solvent. , amides such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone, ketones such as methyl ethyl ketone, methyl isobutyl ketone, methyl probyl ketone, diethyl ketone, and cyclohexanone, and ethers such as dioxane, tetrahydrofuran, ethyl ether, and ethylene glycol diethyl ether. esters such as methyl formate, ethyl formate, methyl acetate, ethyl acetate, ethylene glycol monoethyl acetate, glycol diacetate, etc. M, n
-Butyl alcohol*5ec-Alcohol w such as butyl alcohol, isobutyl alcohol, cyclohexanol, benzyl alcohol, mefL/n chloride, β.

These include chlorine-substituted hydrocarbons such as β'-dichlorodiethyl ether, and nitro compounds such as nitromethane and nitroethane. These solvents are added in an amount of 1 to 100 parts by weight, preferably 5 to 50 parts by weight, based on the resin.

In the present invention, optionally a crosslinking agent 1 a polymerization initiator.

A coloring agent, a charge control agent, a curing agent, a flow regulator, a stabilizer, etc. may be added.

The amount of the shell material used in the present invention can be selected within a wide range in order to exhibit good electrophotographic properties.

In general, the thickness of the shell material formation is determined by the particle size of the core material.
10 times, preferably 2 to 1000 times
Shell material is added to 500 50.

In the present invention, methods for producing core particles include a two-fluid nozzle equipped with a high voltage generator, a pressurized nozzle, and a rotating disk type bell.

Preferably, in order to atomize the molten core material, a two-fluid nozzle or a rotating disk-type bell having a plurality of grooves micro-machined in the atomizing head of the bell, which are opened adjacently so that the injection directions are parallel or intersecting, is used. The window material to be discharged at this time is prepared in advance from a commonly used homomixer, disperser, roll mill, sand mill, ball mill, or sentry mill.

Thoroughly kneaded using a Sassmeyer mill.

The pressure at which the window material is transferred to the head consisting of a nozzle or bell is arbitrarily adjusted to obtain the desired particle size.

When using a two-fluid nozzle, the pumping pressure is generally 1
~100kt/cII preferably 2-10kf/
cJ and hot air pressure of 5 to 50 ky/c! The window material is transferred in about 1 liter. When using a rotating disc type bell, the speed is generally 1 to 200 f/min, preferably 20 f/min.
It is fed at a transfer rate of ~100 f/min. Although the rotating disc bell depends on the window material used, generally 1000 to 100000 rpmK, preferably 5
000~so o o o o rpm. The pumps to be transferred are centrifugal, reciprocating, and single-rotation pumps that can maintain a constant continuous flow with little pulsation, such as Polito pumps, turbo pumps, propeller pumps, gear pumps, and screw pumps.

Divider pump, magnet pump, lab pump.

Diaphragm pumps, bellows pumps, Panton pumps, etc. are preferred.

In the present invention, the high voltage applied to the nozzle or bell is generally 2 to 200 KV, preferably 40 to 90 KV. The above applied voltage also depends on the material used, but if the applied voltage is lower than the above range, the particles will not be sufficiently atomized, and if the applied voltage is higher than the above range, the atomization effect will be saturated and the effect of increasing the voltage will not be realized. .

In the present invention, microcapsules are produced by flying the window material, which has been atomized in advance using an atomizing head, into a medium containing shell material on a grounded surface to be coated. The grounded surface to be coated and the energized atomizing head must be kept at a distance that does not cause dielectric breakdown. In the present invention, the distance between the atomizing head to which voltage is applied and the surface to be coated usually depends on the applied voltage, but when the applied voltage is 80 KV, it is 50 to 500 m, preferably 100 to 200 m. installed separately. By cooling the microcapsule particles obtained in the present invention,
Or sori no matl! l! Microencapsulated particles can be obtained by filtration.

Examples are shown below. Parts are parts by weight.

[Example 1] Polyethylene resin 100 parts Ethylene-vinyl acetate copolymer 20 parts Magnetite
80 parts of the above-mentioned material was cross-mixed for 120 hours using a homomixer, and the melt was supplied to the bell section at a discharge rate of 50 f/min using a metering gear pump equipped with a heating pot and a heating tube. The bell is made by micro-machining the groove to create a nine-G pel (
30,000 rpr using
n, atomized at an applied voltage of -80 KV. On the other hand, 20 parts of styrene-acrylic acid ethyl ester copolymer 3 parts of diethylaminoethyl methacrylate resin
/in in in. The obtained microcapsules were collected, passed through the mouth, and dried to obtain microencapsulated particles. When the particle size distribution was measured using a Coulter counter, the volume average particle size was 10.9 μm + 6.35 μm ~ 20
．． It was found that 92% by weight of the total particles had a particle size between 2 μm.

[Example 2] Polyethylene resin 100 parts Ethylene-vinyl acetate copolymer 20 parts Magnetite
80 parts of the above mixture was mixed with 12 parts using a homomixer.
The molten material kneaded for 2 hours at 0°0° was heated at 50 f/mi using a straightening gear pump equipped with a heating pot and heating tube.
It is supplied to the bell section at a discharge speed of n. The bell is made of 9G pel (manufactured by Landsburg) with a groove of 30,000 mm.
rpm and an applied voltage of -80 KV. On the other hand, 20 parts of styrene-acrylic acid ethyl ester copolymer, 3 parts of methyl methacrylate resin
.

Apply a solution of the above mixture in DMF to the surface to be coated.
'/min. The obtained microcapsules were collected, passed through the mouth, and dried to obtain microencapsulated particles. When the particle size distribution was measured using a Coulter counter, the volume average particle diameter was 10.2 μm, 6', 35 μm ~
Those with a particle size between 20.2μm account for 89% of all particles.
〇 [Example 3] Polyethylene resin 100 parts Ethylene-vinyl acetate copolymer 20 parts Tin oxide
80 parts The above mixture was kneaded at 120'0° for 2 hours using a homomixer.The molten product was fed to the bell section at a discharge rate of 50 f/rnin using a metering gear pump equipped with a heating pot and a heating tube. The bell is a G-pel with micro-machined grooves (
(manufactured by Landsburg) at 30,000 rpm and an applied voltage of -80 KV. On the other hand, styrene-acrylic acid ethyl ester copolymer 20 parts Methyl methacrylate resin 3
Diethylaminoethyl methacrylate resin
A solution prepared by dissolving one part of the above mixture in DMF is supplied to the surface to be coated at a rate of 3'/in. The obtained microcapsules were collected, passed through the mouth, and dried to obtain microcapsule particles. When the particle size distribution was measured using a Coulter counter, the volume average particle size was 10.9 μm + 6.35 μm.
It was found that 85% by weight of the total particles had a particle size between .about.20.2 .mu.m.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an example of a device applicable to the present invention. 1... Rotating bell, 2... Mounted object, 3... Drainage nozzle. 4... Collection tank, 5... Dispersoid tank, 6... Gear pump. 7... - Air turbine motor, 8... Dispersion medium supply pump, 9... Supply hose, 10... Dispersion medium tank.

Claims (1)

[Claims] A microorganism manufactured by K that comprises a first step of forming a core material and a second step of forming a shell when a voltage is applied, and the first step and the second step are performed substantially continuously. capsule particles.