JPS62238578A - Encapsulated toner - Google Patents

Abstract

PURPOSE:To obtain encapsulated toner having elevated fluidity by forming the outer shell of the toner of polyurethane resin and/or polyurea resin and sticking or incorporating silica prepd. by the dry process and treated with titanate type coupling agent to the surface of the outer shell. CONSTITUTION:The encapsulated toner comprises a core material contg. a polymer, a solvent capable of dissolving or swelling the polymer and having >=150 deg.C boiling point, a binder contg. an org. liquid having 100-250 deg.C boiling point which does not dissolve or swell the polymer substantially and the titled recording material, and an outer shell comprising polyurethane resin and/or polyurea resin, sticking silica prepd. by the dry process and treated with a silane coupling agent to the external surface of the outer shell. By this method, an encapsulated toner having dense outer shell and sufficient fluidity is obtd. which generates scarcely secondary aggregation, etc., maintaining superior preservability even if it is stored at room temp. in the atmospheric air for a long time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a capsule toner used for converting a latent image formed in a recording method such as electrophotography into a visible image.

[Background of the Invention] There are three known methods for fixing toner images in recording methods such as electromechanical recording and photographic methods: heat fixing, solvent fixing, and pressure fixing. Due to environmental concerns, heat fixing methods and heat fixing methods that do not use solvents are often used these days.

The heat fixing method has conventionally used a toner formed by solidifying a display recording material with a pinter. The same type of toner is also used in the pressure fixing method, but recently the use of capsule toner has been investigated.

Capsule toner is a microcapsule that is obtained by forming a resin shell that can be destroyed by applying pressure around a core material containing a display recording material such as carbon black and a binder such as a polymer or oil-based solvent. It is a toner.

[Prior Art and its Problems] Conventionally known capsule toners cannot necessarily be said to be satisfactory in terms of various properties originally required as a toner.

For example, toner used as a developer for electrophotography has good powder characteristics, excellent development performance, and PP! It is necessary that the surface of the photoreceptor, which is the surface on which the image is formed, not be contaminated, and in the case of a two-component development method, it is also necessary that the surface of the carrier particles used be not contaminated. Ru. In addition, the toner used in the pressure fixing method is good, and the offset phenomenon to the pressure roller used for pressure fixing (a phenomenon in which the toner adheres to the pressure roller surface and stains the roller) is unlikely to occur. etc. are required.

Therefore, the toner used in the pressure fixing method has two powder properties: fixability to a support medium such as paper (including the shelf life of the fixed image), anti-offset properties, and chargeability and chargeability depending on the developing method used. All of the properties such as electrical conductivity and/or conductivity must be at a high level. However, toners known so far have not always been satisfactory with respect to the above properties.

For example, a capsule toner (Japanese Unexamined Patent Publication No. 76233/1983) is known in which colloidal silica or the like is attached to the surface of the outer shell of the capsule toner in order to improve the fluidity of the capsule toner. According to this, the fluidity of the capsule toner immediately after production is improved due to the influence of colloidal silica. However, due to the hygroscopic or water-absorbing properties of such silica, over time it absorbs moisture present in the air and becomes more cohesive, so the toner powder itself gradually coagulates through the silica powder. There is a tendency for the powder properties and fluidity to deteriorate, such as the formation of lumps.

Furthermore, toner ljt! j! A toner using dry method silica (silica produced by vapor phase oxidation of a silicon halide compound) treated with a titanate coupling agent as a developer in order to improve the lI properties etc.
123850) has been proposed.

According to this, the above-treated dry method silica', :e
The toner's fluidity and storage stability are improved by the vibration.

However, the toner indicated as 41A in the export is 1
This relates to a normal toner consisting of a binder 4a4 fat and a colorant, and applies to capsule toner.
i) It is only described as Noh.

However, unlike normal toners, capsule toners contain a binder such as an oily solvent in the core substance, as described above, so the toner flow may occur, for example, the oily solvent tends to ooze out through the outer shell over time. Capsule toners tend to have unique problems with regard to stability and fixability.

Therefore, simply using dry method silica treated with a titanate coupling agent has not sufficiently improved the fluidity, storage stability, fixing properties, anti-offset properties, etc., which are problems especially with capsule toners. It can not be said.

[Objective of the Invention 1] An object of the present invention is to provide a capsule toner having good powder characteristics and particularly good fluidity.

More specifically, Suikan IJ1 provides a capsule toner with good fluidity and almost no secondary aggregation, even after being stored at room temperature in the atmosphere for a long period of time, as well as immediately after production. With the goal.

Furthermore, the present ffi II aims to provide a capsule toner with excellent fixing properties and anti-offset properties.

[Summary of the Invention] The present invention provides that the core substance comprises a polymer, a high boiling point solvent with a boiling point of 150°C or higher that can dissolve or swell the polymer, and a boiling point of 100 to 250°C that does not substantially dissolve or swell the polymer. A dry method comprising a binder and a display/recording material containing an organic liquid in the range of °C, an outer shell made of a polyurethane resin and/or a polyurea resin, and the surface of the outer shell is treated with a titanate coupling agent. A capsule toner characterized by adhering to or containing silica.

[Effects of the Invention] The capsule toner of the present invention has an outer shell made of a polyurethane resin and/or a polyurea resin, and a dry process silica treated with a titanate coupling agent is attached to or contained on the surface of the outer shell. Because of this, the outer shell is dense and exhibits good fluidity.

The capsule toner of the present invention has a synergistic effect between the above-mentioned shell material and the dry process silica treated with a titanate coupling agent. It has good fluidity and has excellent storage stability.

In addition, the capsule toner of the present invention has a polymer in the core material, and a boiling point of 150 to allow the polymer to be dissolved or engraved.
Contains a binder containing a high-boiling point solvent above ℃ and an organic liquid with a boiling point in the range of 100 to 250 ℃ that does not substantially dissolve or swell the polymer, so it has excellent fixing properties and offset resistance. [Detailed Description of the Invention 1] The capsule toner of 9.11 has a basic structure consisting of a core material and an outer shell formed around the core material.

The core substance of the capsule toner of the present invention is in a paste form,
Included are binders consisting of polymers and oily solvents, and display and recording materials.

Among the components constituting the core material of the capsule toner of the present invention, there is no particular restriction on the polymer that is a component of the binder. Examples of polymers contained as core materials include polyolefins, olefin copolymers, styrene resins, styrene-butadiene copolyesters, epoxy resins, polyesters, rubbers, polyvinylpyrrolidone, polyamides, coumaron-indene copolymers, and methyl vinyl ether.・Maleic anhydride copolymer, amino/resin, polyurethane, polyurea, homopolymer or copolymer of acrylic acid ester, homopolymer or copolymer of methacrylic acid ester, copolymer oligomer of acrylic acid and long-chain alkyl methacrylate, polyacetic acid Examples include vinyl and polyvinyl chloride, and the core material of the capsule toner of the present invention may contain these materials alone or in a mixed state.

Particularly preferred binder polymers are homopolymers or copolymers of acrylic esters, homopolymers or copolymers of methacrylic esters, or styrene-phtadiene copolymers.

The oily solvent which is the structure I & component of the binder includes a high boiling point solvent with a boiling point of 150°C or higher that can dissolve or swell the above polymer (hereinafter also simply referred to as a high boiling point solvent), and a solvent that can substantially dissolve or swell the polymer. An organic liquid having a boiling point within the range of 100 to 250° C. (hereinafter also simply referred to as a non-dissolving organic liquid) is used in combination.

Examples of high-boiling solvents include phthalates (e.g., diethyl phthalate, dibutyl phthalate); aliphatic dicarboxylic esters (e.g., diethyl malonate, dimethyl oxalate) diphosphates (e.g., tricresyl phosphate); , tricresyl phosphate); Citric acid esters (e.g., 0-7 cetyl triethyl citrate, tributyl citrate); Benzoic acid esters (e.g., butyl benzoate, hexyl benzoate); Fatty acid esters (e.g., hexyl benzoate); Decyl myristate, dioctyl adipate): Alkylnaphthalenes (e.g., methylnaphthalene, dimethylnaphthalene, monoisopropylnaphthalene, diisopropylnaphthalene); Alkyldiphenyl ethers (M, o-1m+, p-methyldiphenyl ether): Higher fatty acids or aromatic sulfones Acid amide compounds (e.g., N,N-dimethyllauramide, N-butylbenzenesulfonamide), nitrimellitic acid esters (e.g., trioctyl trimellitate) and diarylalkanes (e.g., dimethylphenylphenylmethane, etc.) diarylethanes such as diarylmethane, ■-phenyl-1-methylphenylethane, 1-dimethylphenyl-1-phenylethane, and ■-ethylphenyl-1-phenylethane, and the core of the capsule toner of the present invention The substances may be contained either in a bulk form or in a mixed form.

Examples of insoluble organic liquids include paraffinic hydrocarbons, naphthenic hydrocarbons, and organic liquid mixtures containing these as main components. Examples suitable for use as boiling point range (initial boiling point to soft point) are 158 to
Paraffinic hydrocarbons at 177°C (e.g. l5opar
G, trade name, manufactured by Exxon Chemical ■, the same applies hereinafter), paraffinic hydrocarbons with a boiling point range of 174 to 189°C (e.g., I
goparH), paraffinic hydrocarbons with a boiling point range of 188-210°C (e.g., l5opar L), paraffinic hydrocarbons with a boiling point range of 207-258°C (e.g., I
naphthenic hydrocarbons with a boiling point range of 162 to 197°C (e.g., 5HELLSQL-040, trade name, manufactured by Shell Chemical Company, hereinafter the same), a boiling point range of 185°C
~220°C naphthenic hydrocarbons (e.g. 5HELLSQ
L-060) and naphthenic hydrocarbons with a boiling point range of 195 to 251"O (eg, 5HELLSQL-070).

The insoluble organic liquid can be mixed with the above-mentioned high boiling point solvent in any ratio, but generally the weight ratio of high boiling point solvent/insoluble organic liquid is 9/l-1/9. It is preferable to mix within a range. A binder is a composition that includes a polymer, a high boiling solvent, and a non-soluble organic liquid.

The mixing ratio of the [polymer 10 high boiling point solvent] and the insoluble organic liquid is preferably in the range of 0.1 to 100 in weight ratio of [polymer 10 high boiling point solvent]/insoluble organic liquid.

Carbon black, grafted carbon black, etc. are commonly used as display recording materials for electrophotographic toners, but various chromatic colorants such as blue, red, and yellow are also used. In the capsule toner of the present invention, these known display and recording materials can be used as display and recording materials.

The core material of the capsule toner of the present invention may contain magnetic particles. As the magnetic particles, known magnetic particles (magnetizable particulate matter) for magnetic toners can be used. Examples of such magnetic particles include magnetic particles made of metal RTI bodies, alloys, or total bending compounds of cobalt, iron, or nickel. Note that when colored magnetic particles such as black magnetite are used as the magnetic particles, the colored magnetic particles such as magnetite can also be used as a component that functions as both the magnetic particles and the blue material.

The resin forming the outer shell of the capsule toner of the present invention is a polyurethane resin and/or a polyurea resin. These resins have appropriate strength and flexibility, and when used as outer shell materials for microcapsules, they form dense outer shells.

The capsule toner of the present invention requires that dry process silica treated with a titanate coupling agent is attached to or contained on the surface of the outer shell formed around the core material as described above.

The dry process silica used in the present invention refers to silica produced by vapor phase thermal decomposition of a silicon halide compound such as silicon tetrachloride, and the method for producing such dry process silica itself is already known.

The average particle size of the dry process silica is 30 nn.
If the average particle diameter of the secondary particles is preferably larger than 30 mIL, the powder properties of the resulting capsule toner will deteriorate, and in particular, the fluidity of the toner will deteriorate.

Dry process silica needs to be hydrophobically treated with a titanate coupling agent.

For example, a capsule toner in which dry process silica that has not been aqueous treated is attached to or contains the outer shell surface may exhibit good flowability immediately after production; Due to its hygroscopic or water absorbing properties, it absorbs moisture present in the air and increases its cohesiveness over time, so the toner powder itself gradually coagulates through this silica and forms agglomerates. Powder properties and fluidity deteriorate.

Therefore, in order to prevent the capsule toner from changing over time, it is necessary that the dry process silica be hydrophobically treated.

Titanate coupling agents include isopropyl triisostearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl tris(dioctyl pyrophosphate) titanate, tetraisopropyl bis(dioctyl phosphite) titanate, and tetraoctyl bis(ditridecyl phosphite) titanate. , tetra(2,2-diallyloxymethyl-1-butyl)bis(di-tridecyl)phosphite titanate, bis(dioctylpyrophosphate)oxyacetate titanate, tris(dioctylpyrophosphate)ethylene titanate, isopropyltrioctanoyltitanate, Isopropyl dimethacrylylisostearoyl titanate, isopropyl isostearyl diacryl titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumylphenyl titanate, isopropyl tri(N-aminoethyl-aminoethyl) titanate, dicumylphenyloxyacetate titanate and dicumylphenyloxyacetate titanate. Mention may be made of isostearoyl ethylene nathanate.

Among these, titanate coupling agents include:
Particularly preferred are isopropyl triisostearoyl titanate, isopropyl tris(dioctylpyrophosphate) titanate, or isopropyl tri(N-7minoethyl-aminoethyl) titanate.

The dry method is a method for hydrophobically treating silica.

For example, a method may be used in which dry silica and a titanate coupling agent are dry mixed in a mixer such as a ball mill.

In the present invention, the state in which the hydrophobically treated silica is attached to the surface of the outer shell of the capsule toner means:
A state in which most of the hydrophobically treated silica particles exist in contact with the surface and width of the outer shell of the toner, and a state in which most of the particles are present in contact with the surface of the outer shell. , most of the hydrophobically treated silica exists in a state where at least some of its particles are buried near the surface of the outer shell, and the state where it is attached or contained refers to the state where it is attached or contained. and a buried state, and also includes a state of existence intermediate between the two.

There is no particular limit to the content of the hydrophobically treated silica, but /
1 & aqueous treated silica is preferably attached or contained within the range of 0.05 to 10% by weight based on the weight of the capsule toner to which it is not attached or contained.
．． It is particularly preferable that it be attached or contained within a range of 1 to 5% by weight.

Next, the capsule toner comprising an outer shell of polyurethane resin and/or polyurea resin of the present invention will be described below.
do.

Display and recording materials and binders (
A method of manufacturing microcapsules by forming an outer shell made of polyurethane resin and/or polyurea resin around a core material dispersed in the form of oil droplets containing magnetic particles (if desired) is already known. ,
These known methods can also be used to produce the capsule toner of the present invention.

For example, an interfacial polymerization method can be mentioned as a method for manufacturing microcapsules using a polymerization reaction that can be used for manufacturing a capsule toner. Also 1
Other examples of the method for producing microcapsules using a polymerization reaction that can be used in the present invention include
Mention may be made of the B polymerization method and the external polymerization method.

The outer shell made of polyurethane resin and/or polyurea resin is made of polyisocyanate such as diisocyanate, triisocyanate, tetraisocyanate, polyisocyanate prepolymer, and polyamine such as diamine, triamine, tetraamine, or two amine groups. It is known that the outer shells of microcapsules can be easily formed by reacting the above-mentioned prepolymers, piperazine and its derivatives, polyols, etc. in an aqueous solvent by an interfacial polymerization method.

A composite walled shell of polyurethane resin and polyurea resin is particularly suitable for forming capsule toners containing magnetic particles within the core material.

After preparing the microcapsules by forming an outer shell around the core material, the microcapsules are separated from the liquid phase, washed with water, and then dried.

This separation and drying operation is usually carried out by heating and drying a slurry containing microcapsules.

Note that the separated and dried microcapsules can be further subjected to heat treatment. This heat treatment particularly improves the powder properties of the capsule toner. Heat treatment is 50-300
It is preferable to carry out at a temperature in the range of 80°C to 1°C.
It is particularly preferable to heat at a temperature in the range of 50°C. The heating time can be determined as appropriate depending on the heating temperature and the type of core material used, but it is usually 10 minutes to 40 minutes.
Heat for 8 hours, preferably 2 to 24 hours.

There are no particular restrictions on the equipment and equipment used for heat treatment; examples of equipment include electric furnaces, Matsufuru furnaces, hot plates, and electric dryers. dryers, fluidized bed dryers, infrared dryers, etc.

Note that metal-containing dyes, charge control agents such as nigrosine, or other arbitrary additives can be added to the outer shell of the capsule toner of the present invention, if desired. These additive substances can be incorporated into the shell of the capsule toner at any point in time, such as when the shell is formed or after the capsule toner is separated and dried.

A predetermined amount of hydrophobically treated dry process silica is mixed into the capsule toner thus prepared. There are no particular restrictions on the mixing method, and commonly used mixers, V-type mixers, etc. can be used.

The obtained capsule toner exhibits excellent powder properties, especially its fluidity.

Next, an example of undeveloped IJJ will be shown. In the example, 1
%" means "% by weight" unless otherwise specified.

[Example 1] l-isopropyl-phenyl-2-phenyl-2-ethane containing 50% by weight of polyisobutyl methacrylate (trade name Niacrybase, MM-2002-2, manufactured by Fujikura Kasei ■) and l5oparaH (aliphatic saturated hydrocarbon mixture) A dispersion (magnetic ink) was prepared by cross-dispersing 40 g of a solution prepared by mixing 40 g of 5:5 magnetite magnetic particles in a 6:5 ratio in an automatic mortar in an automatic mortar.

Separately, add an addition compound of 3 moles of xylylene diisocyanate and 1 mole of trimethylolpropane to 20 g of ethyl acetate (
A solution was prepared in which 9.9 g of D-11ON (trade name: Takene) was dissolved, and this solution was mixed with a dispersion liquid (magnetic ink) of Jingji to prepare an oily phase. However, the preparation of this oily phase mixed liquid (mixture of core material and outer shell forming material) was carried out while controlling the liquid temperature to 25° C. or lower.

An aqueous medium was prepared by adding 0.2 g of diethylenetriamine to 200 g of a 4% aqueous solution of methyl cellulose (methoxy group substitution degree: 1°8, +L average molecular weight: 15000), and the liquid temperature of this aqueous medium was cooled to 15°C.

The above oily phase mixed liquid was emulsified and dispersed in this aqueous medium to obtain a Kichu oil droplet type emulsion in which the average size of oil droplet particles in the emulsion was about 12 μm.

Approximately 10 minutes after making the emulsion funnel 7A, 50 g of a 2.5% by weight aqueous solution of diethylenetriamine was gradually added dropwise.
The mixture was stirred in a constant temperature bath at 0° C. for 3 hours to complete encapsulation.

The resulting microcapsule dispersion was allowed to stand to allow the microcapsules to settle, the upper aqueous layer was discarded, washing water was added in its place, stirred, and allowed to stand.

This washing operation was repeated 20 times to remove methyl cellulose and the like adhering to the surface of the microcapsules. The washed microcapsule slurry was dried in an oven set at 100° C. to obtain a capsule toner. This capsule toner contains dry method silica (product name: Aerosil #200).
: Average particle size 12 m IL: manufactured by Nippon Aerosil ■) treated with isopropyltriisostearoyl titanate (trade name: Prene 7ri 1-TTS: manufactured by Ajinomoto@) is 1% by weight based on the ff+u of the capsule toner. was added and mixed.

This capsule toner had each capsule particle existing independently and exhibited very smooth fluidity.

In addition, the powder properties of the obtained capsule toner were investigated after it was stored in the atmosphere at room temperature for six months.

Each capsule particle existed independently without any change from the time of preparation, and very smooth fluidity was maintained.

[Example 2] In Example 1, dry method silica (Aerosil #20
0), isopropyl tris (dioctyl pyrophosphate) titanate (trade name: Preneact 38S)
A capsule toner was obtained in the same manner as in Example 1 except that dry process silica (Aerosil #200) treated with Ajinomoto Co., Ltd. (Ajinomoto Co., Ltd. $1) was used.

This capsule toner contained ~2 capsule particles independently and exhibited very smooth fluidity.

Furthermore, after storing the obtained capsule toner at room temperature in the atmosphere for six months, the powder characteristics were examined, and it was found that each capsule particle existed independently, unchanged from the time of preparation.
Moreover, extremely smooth fluidity was maintained.

[Example 3] In Example 1, dry method silica (Aerosil #20
0), isopropyl tri(N-aminoethyl-aminoethyl) titanate (trade name: Preneac) 44B
: Ajinomoto ■) treated dry process silica (Aerosil #
A capsule toner was obtained in the same manner as in Example 1 except that 200) was used.

This capsule toner has a state in which each capsule particle exists independently and exhibits extremely smooth fluidity.
It was mu.

After storage for six months, the powder properties were examined and found that each capsule particle existed independently and maintained very smooth fluidity, unchanged from the time of preparation.

[Evaluation of fixing properties and anti-offset properties] The constant It properties and anti-offset properties of each capsule toner obtained in the following were evaluated by the following method.

After developing an electrostatic latent image formed by ordinary electrophotography with each of the above capsule toners to form a toner image,
The toner image was transferred to transfer paper to obtain a visible image. This visible image was fixed at 350 Kg using a pressure fixing roller.
When pressure fixing was performed at a pressure of / cm 2 , a copied image with good fixability and high sharpness was obtained. Even when the surface of each copy image was rubbed with a finger, there was almost no change in the image. Furthermore, although copying operations were repeated 100 times for each using the same pressure fixing roller, almost no toner adhesion to the roller occurred.

As is clear from the results shown above, the capsule toners of the present invention (Examples 1 to 3) have excellent fluidity and storage stability, as well as excellent fixing properties and anti-offset properties.

Claims (1)

[Scope of Claims] 1. The core substance is a polymer, a high boiling point solvent with a boiling point of 150°C or higher that can dissolve or swell the polymer, and a boiling point of 100 to 250°C that does not substantially dissolve or swell the polymer. The outer shell is made of polyurethane resin and/or polyurea resin, and the surface of the outer shell is made of dry process silica treated with a titanate coupling agent. A capsule toner characterized by adhering to or containing. 2. The titanate coupling agent is at least one titanate coupling agent selected from the group consisting of isopropyl triisostearoyl titanate, isopropyl tris(dioctylpyrophosphate) titanate, and isopropyl tri(N-aminoethyl-aminoethyl) titanate. The capsule toner according to claim 1, characterized in that: 3. The content of the dry process silica treated with a titanate coupling agent is within the range of 0.05 to 10% by weight based on the weight of the toner to which the silica is not attached or does not contain. The capsule toner according to claim 1. 4. The capsule toner according to claim 1, wherein the average particle size of the primary particles of dry process silica is 30 mμ or less. 5. The capsule toner according to claim 1, wherein the dry process silica is silica produced by vapor phase thermal decomposition of silicon tetrachloride.