JPS63243965A - Manufacturing method of resin for toner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a toner resin for developing electrostatic images used in electrophotography, electrostatic recording, electrostatic printing, and the like.

[Prior art and its problems]

Conventionally, toner for developing electrostatic images consists of pigments such as carbon, binders, and additives to impart the necessary characteristics to the toner.
For example, it is manufactured by melting and kneading a charge control agent such as a metal-containing azo dye, a wax for preventing offset, etc., cooling, crushing, and classifying. Binders used in such toners include polyester resins, epoxy resins, and the like, but styrene-acrylic polymers are often used because they are easy to adjust the VR of crushability, molecular weight, and physical properties. Possible polymerization methods for such polymers include solution polymerization and emulsion polymerization, but these methods have drawbacks in obtaining a solid polymer having a suitable molecular weight and physical properties as a binder for toner. For example, in the solution polymerization method, high molecular weight is achieved by magnetic rotation, making it difficult to obtain sufficient physical properties, and in the emulsion polymerization method, it is difficult to remove the emulsifier used during polymerization, which may impair the chargeability, which is important for toners. It has its drawbacks. Therefore, suspension polymerization is usually adopted as a polymerization method for styrene-acrylic polymers for toners. In suspension polymerization, a polymerizable monomer and a polymerization initiator are suspended in water using a suspension stabilizer, and polymerized by heating. Examples of such suspension stabilizers include water-soluble organic compounds such as polyvinyl alcohol, polyacrylic acid, and carboxymethyl cellulose, and inorganic suspension stabilizers such as tricalcium phosphate, barium sulfate, and Merck.

If such a suspension stabilizer remains in the polymer, it will adversely affect the chargeability of the toner, so after the suspension polymerization is completed, the polymer is washed with water to remove the stabilizer, but it is complicated to wash thoroughly. It requires a long process.

In addition, tricalcium 7ium phosphate can be solubilized in water by adding an inorganic acid to the suspension, and its removal is relatively easy. It is necessary to use an inorganic acid to make it strongly acidic, with a pH of 3 or less.Ordinary metal polymerization cans will corrode, so a special glass-lined cleaning can is required. Because of this problem, when carrying out suspension polymerization, there is a strong desire for a suspension stabilizer that can be easily removed, and this demand is particularly pronounced for toner resins. In the case of binders for toners, calgenic acid groups are often introduced into the resin to make it negatively chargeable, but in this case it is difficult to maintain a suspension system during polymerization with tricalcium phosphate, so inorganic acid groups that are easy to remove are used. System suspension stabilizers are highly desired.

In recent years, in the electrophotographic industry, in order to streamline toner production and improve toner powder fluidity, pigments and binders are melt-kneaded, cooled, mechanically pulverized, and classified to produce irregularly shaped fine powder toner. From the conventional manufacturing method, a polymerizable mixture in which materials contained in toner such as dyes, pigments, and waxes are dissolved or dispersed in addition polymerizable monomers is processed using a homomixer, a pressure-type homomixer, an ultrasonic homogenizer, etc. Attempts have been made to manufacture fine particle toner by dispersing it in water and carrying out suspension polymerization. In such attempts, particle sizes of 1 to 2
In order to carry out suspension polymerization in the state of fine particles of 5 μm, a suspension stabilizer that can be made into finer particles is required, and a large amount of suspension stabilizer is required for finer particle suspension polymerization. What is desired is something that can be easily removed.

In addition, in recent years, toner production methods have changed in advance to 0.5 to 15 μm particle size instead of the conventional toner binder, dye, pigment, and additives that give the toner the necessary properties by melting, mixing, cooling, crushing, and classifying. Attempts have been made to produce spherical fine particle resin with a 7-year distribution, use this as a core resin, mechanically mix dyes, pigments, etc., and apply it to the surface of the core resin. When obtaining a resin by suspension polymerization, an easy suspension stabilizer is desired.

[Problem that the invention seeks to solve]

The present invention provides a resin for toner, an addition-polymerizable resin having a carboxylic acid group, which eliminates the disadvantages of producing toner and resin for toner by a suspension polymerization method, and which is easier to micronize and remove. The present invention provides a method for producing a toner resin that can maintain a stable suspension system even in suspension polymerization of monomers.

[Means for solving problems]

The present invention provides a method for producing a toner resin, which comprises suspension polymerizing an addition polymerizable monomer using a lithium phosphate salt as a dispersant.

In the present invention, when a toner resin is produced by a suspension polymerization method, when a toner resin containing an organic acid component as a suspension polymerization component is produced by a suspension polymerization method, and when a toner resin is produced by a suspension polymerization method, dyes, pigments, etc. A polymerizable mixture in which the materials contained in the toner are dissolved or dispersed in an addition polymerizable monomer is dispersed in water using a homomixer, a pressure-type homomixer, an ultrasonic homogenizer, etc., and suspension polymerization is performed to produce a toner. When manufacturing directly,
In addition, when the polymerizable mixture contains calgenic acid groups as a component, or when producing fine particle size resin with a volume average particle size of 0.5 to 100 μm, Li phosphate may be used as a suspension stabilizer.
Toner resins are produced by carrying out stable suspension polymerization, which can be easily made into fine particles using a salt, and the suspension stabilizer can be easily removed from the suspension polymer.

In the present invention, the following addition polymerizable monomers are used in suspension polymerization. That is,
Styrene O-p ni -e p-methylstyrene, p
- Styrene and its derivatives such as butylstyrene, ethylene, ethylenically unsaturated monoolefins such as ethylene,
Vinyl halides such as vinyl chloride and vinyl bromide, vinyl esters such as vinyl acetate and vinyl clopionate, methacrylic acid and methyl methacrylate, n-methacrylate
Methacrylic acid esters such as butyl, 2-ethylhexyl methacrylate, β-hydroxyethyl methacrylate, acrylic acid and methyl acrylate, ethyl acrylate, n-butyl acrylate, acrylic [2-ethylhexyl, β-hydroxyglobyl acrylate] Acrylic acid esters such as vinyl methyl ether, vinyl ethyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, N-
N-vinyl compounds such as hinylpyrrole and N-vinylcarbasol, vinylnaphthalenes, acrylonitrile, methacrylnitrile, acrylic acid or methacrylic acid derivatives such as acrylamide, fumaric acid and dimethyl fumarate, motuputyl fumarate, digtyl 7-maleate, 7-malic acid and 7-malic acid mono- or dialkyl esters such as di2-ethylhexyl fumarate, maleic acid, maleic anhydride and dimethyl maleate, dibutyl maleate,
Maleic acid such as motuputil malate, maleic anhydride'f
These monomers, such as mono- or dialkyl maleic esters, or a mixture of these monomers in any combination can be used.

Further, as the polymerizable monomer used in the present invention, the following polymerizable crosslinking agents may be used. That is, divinylbenzene, diethylene glycol diacrylate, dimethacrylate, trimethylolgulonodan triacrylate, methacrylate, and the like.

Initiators used in suspension polymerization in the present invention include known initiators, such as azobisisobutyronitrile, penzoylno! -oxide, methyl ethyl ketosono 4-oxide, iso! Ropyrno-oxycargenate, chemene hydrono-oxycargenate, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, etc. can be used, and the type thereof is not limited.

The phosphoric acid Li salt used in the present invention is not limited in any way by its manufacturing method, but for example, it can be obtained from a reaction salt of phosphoric acid and lithium hydroxide, and hydroxylated with respect to 1 mole of phosphoric acid. It refers to a reaction salt consisting of 1 mol to 3 mol of lithium, preferably 1.0 mol of lithium hydroxide per 1 mol of phosphoric acid.
The amount is 5 mol to 3 mol. That is, lithium hydroxide is 1
If the amount is less than mol, a water-insoluble salt is usually not obtained, and even if a water-insoluble salt is obtained, the effect of stabilizing suspension polymerization is insufficient. The phosphoric acid Li salt is usually used in an amount of 0.001 to 20% by weight based on the addition polymerizable monomer.

In the present invention, suspension stabilizers that are commonly used in suspension polymerization, such as hydroxyethyl cellulose, polyvinyl alcohol, polyacrylic acid, CalR-xymethyl cellulose, etc., or a small amount of an emulsifier as necessary, are used as suspension co-stabilizers. This also includes the combination of the following.

In the present invention, a polymer having an acid group can be dissolved in an addition polymerizable monomer, preferably an addition polymerizable monomer having a carmenic acid group, and then subjected to polymerization. Examples of polymers having acid groups used in this case include carmenic acid group-containing polyester resins, carboxylic acid group-containing polymers such as (meth)acrylic acid copolymers.

The amount of such polymer added is suitably 1 to 70% by weight based on the addition polymerizable monomer.

In the present invention, the following known materials can be used as materials contained in the toner, such as dyes, waxes, etc.

For example, the pigment can be used as a black pigment, channel black,
Furnace black, thermal black, acetylene black, etc. Color pigments include cadmium yellow, hump yellow G, t7 tall fist yellow Ss
These include Piazolone Red, Manent Red 4R, Molybdenum Orange, Asto Violet B, Phthalocyanine Blue B, Fast Sky Blue, 7 Talocyanine Green, Malachite Green, Naphthol Green B, and the like.

As dyes, C, 1, Direct Red 1, c, r.

Direct Red 4, C, 1, Acid Red L.

C, 1, Basic Red 1. C,1, Modern Tread 30, C,1, Direct Blue 1, C,1, Direct Blue 2, C,1, Acid Blue 9, C,1, Acid Blue 15, C,1, Basic Blue 3, C ，
1, Basic Blue 5, C, 1, Modern La Lou 7
,C,I.

Direct Green 6, C, 1, Basic Green 4
, C, I, Basic Green 6, etc.

In order to use the toner as a magnetic toner, it may contain magnetic powder. As such magnetic powder, powders of ferromagnetic metals such as N, ferrous iron, cobalt, and nickel, or powders of alloys and compounds such as magnetite, hematite, and ferrite are used. The content of these magnetic powders is preferably 15 to 70% by weight based on the weight of the toner.

Furthermore, additives such as a charge control agent, a fluidizing agent, a lubricating agent, and a filler may be added to the toner raw material components as necessary.

As charge control agents, those giving positive charge include nigrosine thread U, alkoxylated amines, quaternary ammonium salts, alkylamides, simple substances and compounds of phosphorus and tungsten, molybdate chelate pigments, fluorine-based activators, and hydrophobic agents. silica or the like is used. Those that give negative charge include metal complexes of monoazo dyes, electron-accepting organic complexes, chlorinated polyolefins, chlorinated polyesters, polyesters with excess acid groups, sulfonylamines of copper-7 talocyanine,
Oil black, metal salts of nanthenate, metal salts of fatty acids,
There are resin acid soaps, etc.

Examples of fluidity modifiers include colloidal silica, hydrophobic silica, silicon face, metal soap, nonionic surfactants, and polyvinyl fluoride fine particles.

Examples of cleaning agents include metal salts of fatty acids such as aluminum stearate, calcium stearate, zinc stearate, and zinc laurate. Other examples include colloidal silica and fine powder of tetrafluoroethylene resin.

Fillers include calcium carbonate, clay, Merck, soft pigments, kaolin, silica, and the like.

In addition, waxy substances such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, carnauba wax, Sasol wax, etc. may be added in an amount of about 0.5 to 15 weight Ijk% for the purpose of improving mold release properties during hot roll fixing. You can also do it. Note that the charge control agent and fluidity modifier may be used in combination with the obtained toner particles.

〔Example〕

Next, the present invention will be explained in further detail by showing examples.

In addition, parts and numbers in Comparative Examples, Examples, and Synthesis Examples represent parts by weight.

Synthesis Example-1 Dissolve 98 parts of phosphoric acid in 1960 parts of water, put it in a 5J glass container equipped with a stirrer, and add 7 parts of lithium hydroxide while stirring.
An aqueous solution in which 2 parts were previously dissolved in 1440 parts of water was gradually added. As a result, suspension water containing 5% of fine white precipitate and lithium phosphate salt (Li, PO4) was obtained.

Synthesis Example 2 A fine white precipitate of lithium phosphate salt (Li2HPO4) was synthesized in exactly the same manner as in Synthesis Example-1 except that 48 parts of lithium hydroxide was dissolved in 960 parts of water in advance.
A suspension water containing 5% was obtained.

7 , -'/' , / 7・'7・'/'' Example-1 140 parts of styrene, 25 parts of n-butyl acrylate, M
35 parts of MA, 300 parts of ion-exchanged water, 2 parts of benzoyl chloride oxide, and 40 parts of the suspension obtained in Synthesis Example-1 were placed in a flask equipped with a thermometer, a stirring bar, and a nitrogen inlet tube, and stirred under a nitrogen stream. The temperature was raised to 90°C while stirring, the - of the suspended polymerization solution in the flask was measured, and the temperature was adjusted to 7 to 8 with anhydrous sodium carbonate. After polymerization at 90°C for 16 hours, the temperature was cooled to below 50°C.
Next, the pH was adjusted to 5.5 with hydrochloric acid, stirred for 10 minutes, taken out, filtered, washed with water, and dried, resulting in a diameter of 0.1 to 0.
．． Clear, no-cool toner resin particles containing no lithium phosphate particles were obtained.

Example 2 In Example 1, 40 parts of the suspension obtained in Synthesis Example 2 was used instead of the suspension water obtained in Synthesis Example 1, and after the polymerization was completed, the suspension was adjusted to p) 15.5 with hydrochloric acid. Suspension polymerization was carried out in the same manner as in Example-1 except for the adjustment.
Neat, round toner resin particles free of cod lithium phosphate particles were obtained.

Example-3 100 parts of styrene, 25 parts of n-butyl acrylate, M
MA 75 parts, acrylic acid 3.2 parts, ion exchange water 30
Part 0, Parable of Penzoyl-Oxide 2 parts, Julimar A
C-20H (manufactured by Nippon Tsumugi Co., Ltd., polyacrylic acid) 0.
5 parts were placed in a flask equipped with a thermometer, a stirring bar, and a nitrogen inlet tube, and the temperature was raised to 90°C while stirring under a nitrogen stream. After reacting for 3 hours, the mixture was adjusted to p) 17 to 8 with anhydrous sodium carbonate for synthesis. Add 45 parts of the suspension water obtained in Example-1, then P)(
7 to 8, polymerized for 12 hours, and treated in the same manner as in Example 1 to obtain good 9-shaped resin particles for toner with lithium phosphate particles having a diameter of 0.2 to 0.51. was gotten.

Example-4 800 parts of styrene, 200 parts of n-butyl acrylate,
Elftex 8 (manufactured by Cat Co., Ltd., carbon black) 60 parts, Viscol 550P (manufactured by Sanyo Kasei Co., Ltd., polypropylene wax) 40 parts, Rentrone 5-34 (manufactured by Orient Chemical Co., Ltd., charge control agent) 20 parts , 10 parts of divinylbenzene, and 20 parts of azobisisobutyronitrile were thoroughly stirred using an ultrasonic homogenizer manufactured by Nippon Seiki Co., Ltd.
Three 300 (20 kHz, 300 W) cells were connected in series and dispersion was carried out at a rate of 500 d/min to obtain a polymerizable mixture dispersion. Next, 100 parts of the sodium phosphate solution obtained in Synthesis Example 2 was stirred and dispersed in 4,800 parts of water, and the above polymerizable mixture dispersion was poured into the solution, and while stirring, the above 3.
Using a continuous ultrasonic homogenizer, the speed is 30001 per minute!
The fine particles were suspended at a rate of 1 liter and charged into a reaction vessel which had been replaced with 211 liters of N2. Regular stirring was continued at 70° C. for 10 hours to complete the reaction.

After cooling to room temperature, lithium phosphate was decomposed by adding hydrochloric acid until the pH reached 5.5, followed by dehydration, washing, and drying to obtain a toner. The obtained toner was clean toner resin particles with a volume average particle diameter of 9 μm and a number average particle diameter of 8.1 μm, with no lithium phosphate particles having a sharp particle size distribution.

Example-5 120 parts of styrene, 25 parts of n-butyl acrylate, 55 parts of Hidden, 900 parts of ion-exchanged water, 50 parts of the suspension obtained in Synthesis Example-1, and the suspension obtained in Synthesis Example-2. While thoroughly stirring 50 parts of benzoyl tert oxide and 2 parts of benzoyl teroxide, three cells of an ultrasonic homogenizer US-300 manufactured by Nippon Seiki Co., Ltd. were connected in series to perform a fine particle suspension treatment at a rate of 300,011 j/min, followed by N2 substitution. Prepare it in a heating chamber and heat it at 70℃.
The reaction was terminated by continuing normal stirring for 0 hours, and after cooling to room temperature, hydrochloric acid was added until the pH reached 5.5K, followed by dehydration, washing, and drying to obtain a resin. The obtained toner resin was in the form of sharp and clean lithium phosphate particles with a volume average particle diameter of 11 μm and a number average particle diameter of 10 μm.

Comparative Example-1 Completely the same as Example-1 except that in Example-I, 40 parts of an aqueous suspension containing 5% tricalcium phosphate was used instead of 40 parts of the suspension obtained in Synthesis Example-1. The mixture was subjected to suspension polymerization and treated to obtain pearl-like resin particles for toner. The obtained resin particles had a particle size of 0.2 to 0.6 mm and were irregular products in which tricalcium phosphate particles were mixed. or,
To obtain a sample free of tricalcium phosphate particles, it was necessary to acidify the M greenhouse solution with hydrochloric acid to p)12.

Comparative Example-2 Suspension polymerization was carried out in exactly the same manner as in Example-2, except that in Example-3, a 5% suspension of tricalcium phosphate was used instead of the suspension obtained in Synthesis Example-1. Thirty minutes after the addition of tricalcium phosphate, the suspended dispersion system broke down and became chewy, making it impossible to continue the suspension polymerization, and no ball-like product was obtained.

Comparative Example-3 A toner was synthesized in exactly the same manner as in Example-4 except that 100 parts of a suspension containing 5% tricalcium phosphate was used instead of the M suspension of Synthesis Example-2. The resin particles for toner have a volume average particle diameter of 12 μm and a number average particle diameter of 7.
It contained pro-P tricalcium phosphate particles with a particle size distribution of μm, and could not be used as a toner as it was. or.

To obtain a toner free of tricalcium phosphate particles, it was necessary to reduce the concentration to 12 with hydrochloric acid.

〔effect〕

As shown in the Examples, in the production method of the present invention, suspension stabilizers can be easily removed, and suspension polymerization can be carried out even when an organic acid is included as a suspension polymerization component.

Claims (1)

[Scope of Claims] 1. A method for producing a toner resin, which comprises carrying out suspension polymerization of an addition polymerizable monomer using a lithium phosphate salt as a dispersant. 2. The production method according to claim 1, wherein the addition polymerizable monomer is an addition polymerizable monomer having an acid group. 3. The production method according to claim 1, wherein the addition polymerizable monomer contains a polymer having an acid group. 4. The addition polymerizable monomer is dispersed in water using a homomixer, a pressure homomixer, or an ultrasonic homogenizer to produce fine particle pearl-like resin with a volume average particle size of 0.5 to 100 μm. A manufacturing method according to claims 1 to 3. 5. Dissolve or disperse the materials contained in the toner, such as dyes, pigments, and wax, in the addition-polymerizable monomer and disperse them in water using a homomixer, pressure-type homomixer, or ultrasonic homogenizer, and perform suspension polymerization. Claim 1, characterized in that a toner having a volume average particle diameter of 1 to 25 μm is produced.
The manufacturing method described in Items 3 to 3.