JPH01204060A - Electrophotographic toner - Google Patents

Abstract

PURPOSE:To maintain variance of potential acceptance constant and to improve image quality by introducing positively or negatively charging groups together with sulfobetaine groups into a toner. CONSTITUTION:The toner is prepared by dissolving a polymerizable monomer having a sulfobetaine group and other vinyl monomers as well as a dispersion stabilizer soluble in an organic solvent in an organic solvent having a parameter value higher than that of the resin to be produced by >=1.0, and adding a colorant and the positively or negatively charging material, polymerizing the monomers, and drying the mixture. Said sulfobetaine group is represented by the formula shown on the right in which A is 1-6C straight or branched alkylene or optionally substituted phenylene. The positively charging group is an amino group or silicon atom, and the negatively charging group is an acid group or a halogen, Cr, B, Al, or Fe atom, thus permitting the obtained polymer particles to be small in variance of acceptance potential and to prevent deterioration of acceptance potential under high temperature and high humidity and change of image quality.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an electrophotographic toner, particularly an electrophotographic toner having a sulfobetaine group and a positively or negatively charged group, and a method for producing the same.

(Prior Art and its Problems) Colored powders with six chargeability called toner are used in electrophotographic developers.

The amount of charge on this toner changes depending on changes in temperature and humidity.
It is difficult to maintain a constant amount of charge.

It is known to introduce positively or negatively charged groups into colored powders in order to impart chargeability to toner, but this method alone has the drawback of poor chargeability stability over time and environmental stability, especially at high temperatures. Deterioration under high humidity is significant, and fully satisfactory performance has not been achieved.

(Means for Solving the Problem) As a result of studies, the present inventors discovered that in order to obtain a toner free of the above-mentioned drawbacks, a sulfobetaine group was introduced into the toner powder together with a positively or negatively charged group. .

That is, the present invention provides a sulfobetaine group whose constituent components are represented by the formula (1): [wherein A represents a linear or branched alkylene group having 1 to 6 carbon atoms or a substituted or unsubstituted phenylene group] and (2) an electrophotographic toner having a positive or negatively charged group and containing a colorant, and a method for producing the same.

Sulfobetaine groups are introduced into toner powders in a variety of ways. For example, a single or copolymer of a polymerizable monomer having a sulfobetaine group may be used as part of a binder resin and kneaded and classified, or may be used as a dispersant to form so-called toner particles. It is preferable to form polymerized toner particles using a polymerizable monomer having a sulfobetaine group.

The polymerizable monomer having a sulfobetaine group has the formula as disclosed in JP-A-53-72090: [wherein R1 is a hydrogen atom or a methyl group, R2 and R
1 is the same or different alkyl group of CI-6, R4
is a hydrogen atom or a methyl group, R6 is a hydrogen atom or a C3
an alkyl group of ~, Q is O or NHllllll and nl are the same or different and represent an integer of 1 to 12,
m represents an integer of 0 to 6, and n represents an integer of 1 to 6. ] Compounds represented by: A specific example of such a compound is N.

N-dimedyl~N-methacryloxyethyl-N-(3-
Sulfopropyl)-ammonium betaine, N,N-dimethyl-N-methacrylamidopropyl-N-(3-sulfopropyl)-ammonium betaine, 1-(3-sulfopropyl)-2-vinylpyridinium betaine, and the like.

The toner particles of the present invention contain a positively or negatively charged group in addition to the above-mentioned sulfobetaine group. Examples of positively charged groups include an amino group or a silicon atom, and examples of negatively charged groups include an acid group, a halogen atom, a chromium atom, a boron atom, an aluminum atom, or an iron atom.

The amino group is introduced by copolymerizing an amino group-containing polymerizable monomer during the synthesis of toner particles. Examples of amino group-containing polymerizable monomers include N, N-dimethylaminomethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, and the like. , N-dialkylaminoalkyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylamide, N,N-dimethylaminopropyl (meth)acrylamide, etc. be.

Furthermore, amino groups may be introduced by using amino group-containing polyester or amino group-containing acrylic as a dispersion stabilizer or surfactant during the synthesis of toner particles. Amino group-containing polyester is produced by a known polyester synthesis reaction using alkanolamines such as ethanolamine, jetanolamine, and triethanolamine as one of the components, and amino group-containing acrylic is produced by using the above-mentioned amino group-containing polymerizable monomers. manufactured by polymerization or copolymerization using ” To introduce silicon atoms, during the synthesis of polymer fine powder, a silicon atom-containing polymerizable monomer is copolymerized, or a silicon atom-containing acrylic copolymerized with this is used as a dispersion stabilizer or surfactant. The silicon atom-containing polymerizable monomer has the general formula [wherein R1 is H or CHs, R1 is an alkylene group, net is an alkyl group or phenyl group, and n is an integer from 1 to 5]. Specific examples include:

The introduction of acid groups is carried out during the synthesis of toner particles, such as carboxyl groups,
This is carried out by copolymerizing a polymerizable monomer containing an acid group such as a sulfonic acid group or a phosphoric acid group.

Examples of carboxyl group-containing monomers include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, mozupdel itaconate, and monobutyl maleate.

Examples of the phosphoric acid group-containing monomer include acid phosphooxyethyl methacrylate, acid phosphooxypropyl methacrylate, and 3-chloro-2 acid phosphooxypropyl methacrylate. Further, examples of the sulfonic acid group-containing monomer include 2-acrylamido-2-methylpropanesulfonic acid and 2-sulfoethyl methacrylate. Acid groups may also be introduced by using polyester, acrylic, polyvinyl alcohol, epoxy, or the like containing the above-mentioned acid groups as a dispersion stabilizer or surfactant during the synthesis of toner particles. These can be produced by polymerization or copolymerization of the above-mentioned acid group-containing monomers, or polyester synthesis using sulfophthalic anhydride as a raw material.

Halogen atoms can be introduced by copolymerizing a halogen atom-containing polymerizable monomer or by using a halogen-containing acrylic copolymerized with this as a dispersion stabilizer or surfactant during the synthesis of polymer fine powder. .

Examples of halogen atom-containing monomers include 2°2.2
- Trifluoroethyl acrylate, IH.

+ 1(, 51■-octafluoropentine acrylate, I H, I H, 2H, 2l-r-heptadeca 70
Examples include fluorine-containing monomers such as orodecyl acrylate, and chlorine-containing monomers such as a reaction product of a hydroxyl group-containing monomer and tetrachlorophthalic anhydride.

A chromium atom, a boron atom, an aluminum atom, or an iron atom may be introduced using a polymerizable monomer having these atoms during the synthesis of toner particles. Examples of this type of polymerizable monomer include, but are not limited to, esters and salts of polymerizable organic acids such as acrylic acid, methacrylic acid, itaconic acid, and maleic acid with the above atoms.

Vinyl monomers used in preparing toner particles include styrene, α-methylstyrene, p-methylstyrene,
Aromatic vinyl monomers such as halogenated styrene and divinylbenzene, vinyl esters such as vinyl acetate and vinyl propionate, unsaturated nitriles such as acrylonitrile,
Examples include ethylenically unsaturated carboxylic acid alkyl esters such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, lauryl acrylate, and lauryl methacrylate. can do. In addition, conjugated diolefins such as butadiene and isoprene, acrylamide, methacrylamide, glycidyl acrylate, glycidyl methacrylate, N
-methylol acrylamide, N-methylol methacrylamide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, diallyl phthalate,
Examples include allyl acrylate, allyl methacrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, and tetraethylene glycol dimethacrylate.

In the present invention, the toner particles are polymerized by a non-aqueous dispersion polymerization method, that is, the solubility parameter of the resin produced by the polymerization is
The polymerization is carried out in an organic solvent of 0 or more. In this specification, "solubility parameter" refers to ■, barrel (B u
Polymer Handbook (Polymer Handbook) by rrel l)
er Handbook), Wiley-1nterscience,
The information on pages 1V-337 to IV-348 is adopted. Organic solvents that can be used include ketones, such as acetone,
Cyclohexanone: dioxane; acetonitrile; dimethylformamide; ether alcohols such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether,
Propylene glycol monoethyl ether, propylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ethylene,
Dipropylene glycol monomethyl ether, nopropylene glycol monoethyl ether: Alcohols such as methanol, ethanol, isopropanol, n-
Butanol, i-butanol, (-butanol, n-hexanol, cyclohexanol ethylene glycol,
These include propylene glycol and dipropylene glycol. Preferably, 50% by weight or more, more preferably 80% by weight or more of the organic solvent is occupied by alcohol and/or ether alcohol solvent.

As the dispersion stabilizer soluble in the organic solvent used in the present invention, commonly used dispersion stabilizers are suitably used. Examples of this type of dispersion stabilizer include cellulose (hydroxyethylcellulose, hydroxypropylcellulose, cellulose acetate butyrate, hydroxybutylmethylcellulose, hydroxypropylmethylcellulose,
Cellulose propionate, etc.), polyvinyl alcohol (polyvinyl acetate, ethylene-vinyl alcohol copolymer, vinyl alcohol-vinyl acetate copolymer, etc.),
Other polymeric polymers (polyvinylpyrrolidone, polyacrylic acid polyvinyl methyl ether, acrylic resin, epoxy resin, styrene-acrylic resin, etc.), polycondensation polymers (polyester resin, polyethyleneimine, etc.), amphoteric group-containing resins (e.g. JP Showa 56-151
727, zwitterionic group-containing polyester produced in JP-A-57-405'22, zwitterionic group-containing epoxy, etc.).

Polymerization is usually carried out using a polymerization initiator. As the polymerization initiator, ordinary ones may be used.

For example, peroxides such as benzoyl peroxide, di-butyl peroxide, cumene hydroperoxide, di-butylperoxy 2-ethylhexanoate, azobisisobutyronitrile, 2.2°-azobis(2,4- dimethylvaleronitrile), 2゜2゜-azobis(4-methoxy-2,4-dimethylvaleronitrile), dimethyl 2
, 2°-azobisisobutyrate, and other azo compounds are used.

Also, 2.2°-azobis(2-amidinopropane) dihydrochloride, 2,2°-azobis(N,N'-dimethyleneisobutyramidine), 2.2°-(N.

Introduction of amino groups is possible by using polymerization initiators such as No-dimethyleneisobutyramidine) dihydrochloride, 4,4°-azobis(4-cyanopentanoic acid), potassium persulfate, ammonium persulfate, etc. Introduction of acid groups is possible by using a polymerization initiator. These are used lpl or in a mixture of two or more. The amount used is usually selected in the range of 0.1-10%, preferably 0.2-7%, based on the total monomers. As described above, a charge may be imparted to the particles by the polymerization initiator.

The average particle diameter of the toner particles according to the present invention is preferably 1
It has a particle size of ~50 μm, more preferably 3 to 30 μm.

The toner particles of the present invention are colored. There are two methods for coloring particles: preparing white polymer particles in advance and then wet-impregnating them with a colorant, or preparing colorless polymer particles in advance and dry-coating them with a colorant. A preferred method is to introduce a polymerizable group into the colorant and then copolymerize it with other monomers. Colorants that can be used include inorganic pigments such as carbon black, titanium white, and cadmium yellow, C,1, and pigment yellow 1.
．． Acetoacetate arylamide monoazo yellow pigments such as 3, 74, 97, and 98, C, t.

Pigment Yellow 12, 13, 14 and other acetoacetic acid arylamide yellow pigments, c, r, solvent.
Yellow 19, 77, 79, C8! , yellow dyes such as Disperse Yellow 164, C,1, pigments, etc.
Red 5, 48, 49:11, 53:1. Same 57,
57:l, 81. Red or pink pigments such as 122, C,1, Solvent Red 49, 52, 58
, grade 8 red dye, c, r, pigment blue 1
Organic dyes and pigments such as blue dyes such as 5:3 copper phthalocyanine and derivatives thereof, and green pigments such as C1, Pigment Green 7, and Pigment Green 36 can be used. The amount of the colorant to be blended is 2 to 20% by weight, preferably 4 to 1% by weight based on the toner particle weight.
It is 5 weight 1%.

During polymerization, other additives may be added as desired, such as magnetic powder (magnetite, ferrite, etc.), polyethylene wax,
Polypropylene wax, silicone compounds, etc. may also be blended. The amount of additives is 0 based on the total polymerizable monomer.
．． 1 to 5% by weight is preferred.

The polymerization conditions are generally carried out in a nitrogen atmosphere at a temperature range of 40 to 150'C, but are not limited thereto.

(Effects of the Invention) The polymer particles of the present invention show little change in the amount of charge, and hardly any decrease in the amount of charge is observed even under high temperature and high humidity. Therefore,
When these particles are used in toner, etc., no change in image quality etc. is observed because the band "ffi" is constant.

(Example) The present invention will be explained in more detail with reference to Examples. The invention is not limited to these examples.

Synthesis Example 1 (Synthesis of Colorant) In this example, synthesis of a blue dye for imparting vinyl polymerizability will be described.

Add Neozapo to an IQ round bottom flask equipped with a reflux tube, calcium chloride tube, thermometer, and magnetic cooler.
50 parts by weight of nl31ue807 (manufactured by BASF) and 500 parts by weight of dehydrated 1,4 dioxane were charged and dissolved while flowing nitrogen. 10 parts by weight of methacryloyl isocyanate was added thereto, and the reaction was continued for 1 hour at room temperature.

After the reaction, dioxane was removed using an evaporator, followed by washing and filtration with hexane, further washing with methanol, and drying. When the obtained blue solid was analyzed by IR and NMR, it was confirmed that methacryloyl isocyanate was added to the -Nl-1 moiety of the dye.

Synthesis Example 2 (Synthesis of Colorant) Using the same method as Synthesis Example 1, Waxolin Red
14 parts by weight of methacryloyl isocyanate was added to 50 parts by weight of O (manufactured by IC1).

Formation Example 3 (Synthesis of Coloring Agent) In the same manner as Synthesis Example 1,
11 parts by weight of methacryloyl isocyanate was added to 50 parts by weight of low 075 (manufactured by BASr').

Example 1 (Synthesis of colored particles) Isopropanol 3 was placed in a tC separable flask equipped with a reflux tube, thermometer, stirrer, N, inlet, and monomer inlet.
00 parts by weight, 100 parts by weight of deionized water, 6 parts by weight of polyacrylic acid, 8 parts by weight of polyvinyl acetate, and 1-(
0.4 parts by weight of 3-sulfopropyl)-2-vinylpyridinium betaine was dissolved. After raising the temperature to 80°C, 73 parts by weight of styrene (St), 15 parts by weight of 2-ethylhexyl acrylate (2EHA), 2.0 parts by weight of octafluoroethyl acrylate, and 10 parts by weight of the blue dye of Synthesis Example 1. A mixed solution of 4 parts by weight of benzoyl peroxide was added and polymerized for 18 hours. The dispersant was removed from the particle dispersion by dialysis, and this was filtered and dried to obtain a toner.

The characteristic values and environmental test measurement results are shown in Table 2.

Examples 2 to 5 (Synthesis of colored particles) Table 1 shows the formulations of toner particles synthesized using the same method.

Comparative Examples 1 to 2 Table 2 shows the formulations of toner particles synthesized in the same manner except for the polymerized monomer having a sulfobetaine type amphoteric ionic group. Table 2 shows these characteristic values and environmental test measurement results.

Note) l) N,N-dimethyl-N-methacryloxydiyl-N-(3-sulfopropyl)-ammonium betaine 2) N,N-dimethyl-N-methacrylamidopropyl-N-(3-sulfopropyl)- ammonium betaine 3) l-(3-sulfopropyl)-2-vinylpyridinium betaine 4) 2-ethylhexyl acrylate 5) methyl methacrylate 6) n-butyl acrylate 7) diisopropenylbenzene 8) methacrylic acid 9) N, N-Dimethylaminoethyl methacrylate 10) Hebutamethylsiloxanylethyl methacrylate 11) Azobisisobutyronitrile 12) Azobisisobutyronitrile Tests of Examples and Comparative Examples were conducted using iron based on 1.8 parts by weight of toner particles. powder 10
The experiment was carried out by mixing 0 parts by weight.

The values are measured after mixing in a ball mill for 200 minutes.

2) Regarding the blow-off charge amount measured after mixing for 1 minute in a ball mill, based on the value measured after mixing for 200 minutes, O near 5% or more, △ near 5 to 50%, ×: 50%
Shown below.

3) Measurement results using a Q/D meter manufactured by Epping Co., Ltd. of the toner composition mixed for 1 minute in a ball mill: ○: 2% or less;
Δ: 2 to 10%, ×: 105 or more.

Patent applicant Nippon Paint Co., Ltd.

Claims (1)

[Claims] 1. Its constituent components are formula (1): ▲ Numerical formula, chemical formula, table, etc. ▼ [In the formula, A is a linear or branched alkylene group with 1 to 6 carbon atoms, a substituted or Indicates an unsubstituted phenylene group. ] An electrophotographic toner having a sulfobetaine group represented by the following and (2) a positive or negatively charged group and containing a colorant. 2. The electrophotographic toner according to claim 1, wherein the positively charged group is an amino group or a silicon atom. 3. The polymer particles according to claim 1, wherein the negatively charged group is an acid group, a halogen atom, a chromium atom, a boron atom, an aluminum atom or an iron atom. 4. Formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, A has the same meaning as above. ]. The polymerizable monomer having a sulfobetaine group and other vinyl monomers as necessary are produced in an organic solvent having an SP value that is 1.0 or more larger than the parameter value (SP value) of the resin. 2. The method for producing an electrophotographic toner according to claim 1, wherein the toner is polymerized in the presence of a dispersion stabilizer, a colorant, and a positively charged or negatively charged substance that are soluble in a solvent, and then dried. 5. A polymer monomer having a sulfobetaine group has the formula: ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [In the formula, R_1 is a hydrogen atom or a methyl group, R_2 and R_3 are the same or different alkyl groups of C_1 to ___■, R_4 is a hydrogen atom or a methyl group, R_5 is a hydrogen atom or an alkyl group of C_1 to C_3, Q is O or NH, m_1 and n_1 are the same or different and are 1 to
represents an integer of 12, m_2 is an integer of 0 to 6 and n_
2 represents an integer from 1 to 6. ] The manufacturing method according to claim 4, wherein the compound is a compound represented by: 6. The manufacturing method according to claim 4, wherein the positively charged substance is a compound containing at least one of an amino group and a silicon atom. 7. Negatively charged substances are acid groups, halogen atoms, chromium atoms,
5. The manufacturing method according to claim 4, which is a compound containing at least one of a boron atom, an aluminum atom, and an iron atom.