JPH023076A - Production of 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 toner used in copying machines, etc. The present invention relates to a method for manufacturing a toner in one step by mixing and suspending a monomer containing various toner additives and carrying out suspension polymerization. .

(Prior art) Toners have traditionally been made by blending pigments, charge control agents, wax, and copolymer resins such as styrene-acrylic acid esters, etc., melting the mixture under heat, then kneading it with rolls, cooling it, and pulverizing it. The particles were manufactured to the desired particle size.

However, such conventional manufacturing methods have complicated processes and large energy losses.

Therefore, in recent years, the problems of this method have been improved and a monomer mixture having an ethylenically unsaturated double bond such as a mixture of styrene and acrylic acid ester, a pigment such as carbon black, and a charge control agent such as nigrosine are used. Several methods have been proposed in which a toner additive such as a wax component such as polypropylene/wax is mixed and polymerized in one step to obtain a toner (for example, Japanese Patent Publication No. 55-50962, Japanese Patent Publication No. 55-50962; -!;0gg No. 3 Publication, JP-A-Sho!;
6-/109'l! :Refer to the publication).

(Problem to be Solved by the Invention) However, since the toner additives are insufficiently dispersed in the monomer component by this method, there is a possibility that their dispersion in the copolymer is non-uniform. However, it cannot fully demonstrate its performance as a toner and has not yet been put into practical use.

(Means for Solving the Problem) Therefore, the inventors of the present invention have made extensive studies to overcome these drawbacks, and as a result, the present inventors have found that when dispersing toner additives in monomers having ethylenically unsaturated double bonds, The present inventors have discovered that the above problems can be solved by carrying out a suspension polymerization reaction after adding and dispersing a compound represented by a specific structural formula, and have arrived at the present invention.

That is, an object of the present invention is to provide a method for obtaining a toner in which l-toner additives are sufficiently and uniformly dispersed through a one-step reaction.

This purpose is to combine a monomer having an ethylenically unsaturated double bond with a pigment, an additive, and a compound having the structure represented by the following general formula (1) (wherein R is the number of carbon atoms in grams). −
t ff represents an alkyl group, and n represents an integer of 2 to 200. ) is added and dispersed, and then the dispersion is subjected to suspension polymerization in an aqueous suspended temperature bath.

The present invention will be explained in detail below.

The monomer having an ethylenically unsaturated double bond used in the present invention is not particularly limited as long as it is used in producing toner, and specifically,
It is preferable to use a styrene monomer or an acrylic acid monomer.

Styrenic monomers include styrene, vinyltoluene,
Examples include ethylstyrene, p-chlorostyrene, and I)n-butylstyrene, and preferably styrene or vinyltoluene is used.

Examples of the acrylic acid monomer include ethyl acrylate, ethyl methacrylate, butyl acrylate or butyl methacrylate, methyl acrylate, methyl methacrylate, propyl acrylate, etc., and preferably acrylic acid n
-butyl, n-butyl methacrylate or methyl methacrylate.

These monomers may be used alone or in combination, and if necessary, cationic monomers such as N,N-dimethylamine ethyl methacrylate), N, N-diethylaminoethyl methacrylate, and vinylpyridine may be used. Monomers may also be used in combination.

Hereinafter, these monomers will be collectively referred to as "polymerizable monomers."

As the pigment, any pigment used in conventional toners can be used without particular limitation, and specifically, carbon black, iron oxide, zinc oxide, titanium oxide, etc. can be used.

The carbon black is preferably one that is used in ordinary toners, such as channel black or furnace black, and has a particle size/S-Omμ of the order of magnitude. The amount added is / based on the polymerizable monomer.
A weight ratio of 10 to 10 is preferred, and a ratio of 3 to 7 is particularly preferred; if it is too small, the degree of blackness will be insufficient, and if it is added in excess, no significant improvement in blackening will be observed, making it uneconomical. As the additive, a charge control agent and a wax are usually used, and the charge control agent may be one that is commonly used, and examples thereof include nigrosine, aniline flu phthalocyanine pur, τ azo metal-containing dye, and chrome yellow. When using nigrosine as a charge control agent, particles with a small particle size are preferred in order to shorten dispersion time, specifically 3 to 30 μm.
It is preferable that the degree of

The amount of addition 1 is preferably 5% by weight, preferably 2 to 3% by weight, based on the polymerizable monomer.

If it is too small, the M main control characteristics of the toner tend to be insufficient and a stable image cannot be obtained, and even if it is too large, the m1l characteristics cannot be improved, which is not preferable. The wax is not particularly limited as long as it imparts releasability to the toner; for example, polypropylene 1
Waxes commonly used in toners include waxes such as Nwanx, polyethylene' wax, and microcrystalline wax. The amount of C added is 7 to 5% by weight based on the polymerizable monomer! lXj: Well, especially -~
The content is preferably 3% by weight. If the amount is too small, the mold releasability will be insufficient, and if it is too much, no significant improvement in the mold releasability will be observed, which is undesirable.

In the present invention, when dispersing pigments and additives in the above-mentioned monomers, it is important to add a compound having a structure represented by the following general formula (1).

Here, in the general formula (1), R represents a carbon number of g to Sg2, preferably /2 to g, and n represents an integer of - to .1Oθ. Such a compound can be obtained as a reaction product, for example, by copolymerizing an α-olefin and a maleic anhydride total polymerization initiator according to a conventional method. In addition, +i can be used alone or in a mixture thereof in such a compound. The amount added is preferably 0.5 to 70 parts by weight, particularly preferably 0.5 to 70 parts by weight, based on the polymerizable monomer.

If the amount added is too small, a sufficient dispersion effect cannot be obtained, and even if it is used in excess, no significant improvement in the dispersion effect is observed, so from an economical point of view, it is not suitable.

In addition, if the carbon number of OR in general formula (1) is smaller than g, the compatibility with the monomer will be poor, and a sufficient dispersion effect will not be obtained, and if the carbon number of R is larger than 5 g, the softening point will decrease. It is not preferable because it becomes expensive and takes a long time to dissolve, resulting in poor workability.

In the present invention, the above-mentioned various components are uniformly dispersed, and at that time, a crosslinking agent is added to the polymerizable monomer in an amount of 0.1 to 2% by weight so that the polymer has a desired gelation rate. It is good to add it.

As for the gelation rate, the content of resin insoluble in tetrahydrofuran is IO-! ;0% by weight, preferably 3S-95% by weight. If the gelation rate is too low, the polymer will be too soft and the resulting toner will cause caking, and if the gelation rate is too high, the softening point of the toner will be too high, making it difficult to use the toner. This is not preferable because a large amount of energy is required to melt the material.

Any commonly used crosslinking agent may be used as such a crosslinking agent, such as divinylbenzene, divinylnaphthalene/,
Examples include compounds having two novinyl groups such as ethylene glycol dimethacrylate and divinyl ether, and compounds having three vinyl groups such as trimethylolpropane triacrylate, and these can be used individually or in combination. .

Note that a polymerization initiator is further added to the dispersion of the present invention. Any commonly used polymerization initiator may be used, such as azopisui.

Butyronitrile, azobisonitrile, q-dimethylvaleronitrile, etc. are used.

In the present invention, it is important to uniformly disperse these various components, and for this purpose, a compound represented by the general formula fl) is used, but the resulting uniform dispersion remains stable during the polymerization process. A toner having good toner physical properties can be obtained in one step.

In order to prepare such a uniform dispersion, for example, the monomers are heated to a temperature of 5 to /θ0°C, and the pigment, pigment, Additives and the compound of general formula (1) are added so that each is uniformly dispersed.

After the obtained homogeneous solution is gradually cooled to room temperature, a polymerization initiator is added to obtain the dispersion of the present invention.

Note that when preparing this dispersion, the order in which the various components are added is not particularly limited, and they may be added one by one or all at once, but it is preferable to add the wax component first. After first uniformly dissolving, add other additives sequentially,
It is better to disperse.

The resulting dispersion is then subjected to suspension polymerization in an aqueous suspension bath. Normally, the dispersion is poured and strongly stirred with a homomixer or homogenizer to form suspended particles of the desired particle size, and then the temperature is raised to a predetermined temperature while stirring slowly to perform suspension polymerization. , the stirrer may be a homomixer, homogenizer, etc. and may be continued at a low speed of 11,000 rpm or less,
Alternatively, suspension polymerization may be carried out by replacing the stirrer with another one.

The aqueous suspension bath refers to inorganic and organic suspension stabilizers normally used in suspension polymerization, such as silica powder bentonite, calcium phosphate, polyvinyl alcohol, hydroxyethylcellulose, methylhydroxyethylcellulose,
A suspension stabilizer such as gelatin is preferably used at a concentration of 0.00/-
5 parts by weight were uniformly dispersed in 100 parts by weight of water. Each of these suspension stabilizers can be used alone or as a mixture of two or more, and a surfactant such as sodium lauryl sulfate, sodium dodecylbenzenesulfonate, etc. can be used in addition to water.

o, ooi-o, and s parts by weight may be used in combination with each part by weight.

The dispersion to be poured is usually 10 to 100 parts by weight, preferably 20 parts by weight, per ioo parts by weight of the aqueous suspension bath. Parts by weight of rO are used, and the polymerization conditions are usually 0 to 90° C. in an inert gas atmosphere for about 6 to 10 hours.

The particle size of the resulting toner particles varies depending on the stirring speed, but is usually at a stirring speed of qoooo~gooorpm! ---
, 2j μm, it is preferable that the toner particles have a true spherical shape.

After the polymerization reaction is completed, the reaction solution is cooled to room temperature, and the toner particles are filtered and dried to obtain the desired toner.

(Effects of the Invention) According to the present invention, a toner in which toner additives are uniformly dispersed can be manufactured.

(Example) Example/ 79 parts of styrene, 20 parts of n-butyl acrylate, and
1 part of divinylbenzene is mixed and is hereinafter referred to as monomer.

) 1000~/! ;θO
Add polypropylene wax (s) while stirring at rpm.
sop (manufactured by Sanyo Chemical Co., Ltd.) was added and stirred for 30 minutes to dissolve.

Next, 0 g of a compound represented by the general formula (1), where R = alkyl group having 76 carbon atoms, and n = 0, was added and stirred for io minutes.
A portion of nigrosine λ was added, stirred for 60 minutes, and a spot test was performed to find that it was uniformly dispersed. Next, 5 parts of carbon black was added and dispersion was continued for 30 minutes, then cooled to room temperature with stirring, and 2 parts of azobisin butyronitrile was added and stirred for 30 minutes. This monomer mixture was poured into tIoo parts of a suspension bath containing 1 part of polyvinyl alcohol, and after being sufficiently purged with nitrogen, the mixture was heated at 6 o o o rpm using a homomixer.
to form suspended particles by stirring three portions at 70°C.
Polymerization was carried out for 9 hours at 100 mL and then for 9 hours at GO'C.

Thereafter, the polymerization was stopped by cooling. The reaction product was taken out, filtered, washed, and dried to obtain a polymer with an average particle size of 4'μm.
I got the department. When this material was observed under a microscope, it was found to be true spherical black particles in which the additive was uniformly dispersed.

Example 2 The same method as in Example 1 was carried out except that 7 parts of a compound having an alkyl group of R=028 to 8 and n=10 were used as the compound of general formula (1). A spot test showed that it was evenly distributed.

Microscopic observation of the polymer showed that it was as good as in Example 1, with an average particle size of /F and a yield of 70 g.

Example 3 As a compound of general formula (1), an alkyl group of R=C:8,
The same method as in Example 1 was carried out except that 9 parts of the compound with n=100 was used. Spot tests were almost evenly distributed. The polymer was almost the same as in Example, but contained a small amount of translucent particles. The average particle size of this polymer was 75 μm, and the yield was 107 parts.

Example 1 The same method as in Example 1 was carried out except that 70 parts of a compound having R=C, .about.16 alkyl groups, and n-2 were used as the compound of general formula (1). Spot tests were evenly distributed. In addition, microscopic observation of the polymer showed good results similar to those in Example /, and the average particle size was / JJ ttiTl %.
The yield was 1/15 parts.

Comparative Example/Processed in the same manner as in Example 1 except that the compound of general formula (1) was not used.

A spot test showed that the additive and the sulfur were hardly dispersed, showing separated spot marks, mostly to the extent of aggregates.

Moreover, the polymer of this product was transparent or semi-transparent particles in which the additive was aggregated and localized within the particles.

Comparative Example In general formula (1), R = C6 alkyl group, r,
==/Processed in the same manner as in Example/, except that 9 parts of the compound of j was used. In the spot test, it was observed that the additive was slightly dispersed, but the additive and monomer were considerably separated, indicating that the dispersion was insufficient. In this polymer, many particles were observed to have a mottled pattern due to localized agglomeration of the additive within the particles.

The results of Examples/--G and Comparative Examples 1 and 2 are summarized in Table 1.

Claims (1)

[Claims] (1) Monomers with ethylenically unsaturated double bonds, pigments, additives, and compounds having the structure represented by the following general formula (1) ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (1 ) (wherein, R represents an alkyl group having 8 to 58 carbon atoms, and n represents an integer of 2 to 200) is added and dispersed, and then the dispersion is subjected to suspension polymerization in an aqueous suspension bath. A toner manufacturing method characterized by: