JPH0810356B2 - Toner binder for electrophotography - Google Patents

Description

The present invention relates to a toner binder for electrophotography.

(Problems to be Solved by Conventional Techniques and Inventions) In electrophotography, an electrostatic latent image is visualized with toner,
A toner image is formed on paper or the like, and a method using a heat roll is widely adopted to fix the toner image. In this method, the lower limit fixing temperature (hereinafter abbreviated as MF) is desirably low, and the temperature at which offset to the heat roll occurs (hereinafter abbreviated as HO) is desirably high.

In order to satisfy these two demands, it has been proposed that the toner binder has a wide molecular weight distribution ranging from low molecular weight to high molecular weight (for example, JP-B-60-20411 and JP-B-51-23354). Gazette).

In the above, for example, a cross-linking agent is used to broaden the molecular weight distribution to the higher side.

However, as noted above, the use of cross-linking agents
If the molecular weight distribution is widened to the higher side, the MF becomes high.

It is also possible to use a method in which a high molecular weight portion is produced by suspension polymerization without using a crosslinking agent, and the separately produced low molecular weight polymer is mixed and dissolved in a solvent.

However, in the above method, since the molecular weights of the two are largely different from each other, it is difficult to be completely uniform, and at the time of toner production, additives such as a coloring material such as carbon black and a charge control agent are not uniformly dispersed, It has the drawback that the charging characteristics are not stable during running during copying, causing toner fogging and scattering.

The present invention is to solve the above problems, and to provide an electrophotographic toner binder comprising a polymer having a wide molecular weight distribution and having favorable properties in terms of HO and MF (low MF and high HO). The first purpose.

In addition, the present invention provides a toner binder for electrophotography which is excellent in running properties during copying, in which a coloring material such as carbon black and additives such as a charge control agent are uniformly dispersed during toner production. The purpose of.

(Means for Solving the Problems) The present invention includes (a) a high molecular weight copolymer (A) containing a portion having a molecular weight of 300,000 or more in I. molecular weight distribution, and a molecular weight of 1000 to 3 in II. Containing a low molecular weight polymer (B) containing 10,000 parts and an intermediate molecular weight copolymer (C) containing a part having a molecular weight of 50,000 to 200,000 in the III. Molecular weight distribution, and having a weight average molecular weight of 200,000 to The value of the ratio of the weight average molecular weight to the number average molecular weight is 40-100.
And (b) the monomers constituting the high molecular weight copolymer (A) and the intermediate molecular weight copolymer (C) are, respectively, I. styrene or a styrene substitute, and II. Two or more kinds of acrylic acid ester and / or methacrylic acid ester, and (c) the monomer constituting the low molecular weight polymer (B) is I. styrene or a styrene substitution product, and II. Styrene. Or a styrene substitution product and two or more kinds of monomers of acrylic acid esters and / or methacrylic acid esters, and (d) the high molecular weight copolymer (A) is a polyfunctional polymerization initiator. In the presence of (D), it is assumed that the monomers are copolymerized, and (e) the polyfunctional polymerization initiator (D) is a polymer having two or more peroxide groups in I.1 molecule. Functional polymerization initiator, II.1 one or more peroxide groups in the molecule, Selected from a polyfunctional polymerization initiator having one or more polymerizable unsaturated groups, (f) the intermediate molecular weight copolymer (C), the high molecular weight copolymer (A) and the low molecular weight polymer (B). In the presence of), a toner binder for electrophotography, characterized in that it is obtained by copolymerizing monomers in a substantially solvent-free manner.

In the present invention, in the dynamic viscoelastic property in a molten state at 150 ° C., the absolute value of complex viscosity | η * (20) | at a frequency of 20 Hz is 1000 to 15000 poise, and the absolute value of complex viscosity at 1 Hz is | η * (1) | is 5000 to 60,000 poise
And the value of the ratio of the above absolute values | η * (20) | / | η
* (1) | is preferably 0.20 or less.

 Hereinafter, the present invention will be described in detail.

The binder of the present invention comprises I. a high molecular weight copolymer (A) containing a portion having a molecular weight of 300,000 or more in the molecular weight distribution, and II. A low molecular weight polymer containing a portion having a molecular weight of 1000 to 30,000 in the molecular weight distribution ( B) and III. An intermediate molecular weight copolymer (C) containing a portion having a molecular weight of 50,000 to 100,000 in the molecular weight distribution, the weight average molecular weight is set to 200,000 to 1,000,000, and the weight average molecular weight is And the number average molecular weight ratio is 40-100
And the resin mixture.

High molecular weight copolymer (A) and intermediate molecular weight copolymer (C)
The monomers constituting the above are respectively defined as two or more kinds of I. styrene or a styrene substitution product and II. Acrylic acid ester and / or methacrylic acid ester.

Further, there are two types of monomers constituting the low molecular weight polymer (B): I. styrene or styrene substitution product, II. Styrene or styrene substitution product, and acrylic acid ester and / or methacrylic acid ester. It is selected from the above monomers.

Examples of the styrene or styrene substitution product include styrene, alkyl styrene (for example, α-methyl styrene,
p-methylstyrene) and the like. Preferred is styrene.

Examples of the acrylic acid esters and / or methacrylic acid esters, that is, (meth) acrylic acid esters, include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. , Lauryl (meth) acrylate, stearyl (meth) acrylate and other alkyl groups having 1 to 18 carbon atoms; hydroxyl group-containing (meth) acrylates such as hydroxylethyl (meth) acrylate; dimethylaminoethyl (meth)
Examples thereof include amino group-containing (meth) acrylates such as acrylate and diethylaminoethyl (meth) acrylate; nitrile group-containing (meth) acrylic compounds such as acrylonitrile and (meth) acrylic acid.

Of these, preferably, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate,
(Meth) acrylic acid and a mixture of two or more thereof.

As the monomer constituting the high molecular weight copolymer (A), the low molecular weight polymer (B) and the intermediate molecular weight copolymer (C),
You may use together vinyl ester other than (meth) acrylic acid ester, an aliphatic hydrocarbon vinyl monomer, etc.

Examples of the vinyl ester include vinyl acetate and vinyl propionate, and examples of the aliphatic hydrocarbon vinyl monomer include butadiene.

The high molecular weight copolymer (A) can be obtained by copolymerizing the above monomers in the presence of a polyfunctional polymerization initiator (D) having a polyfunctional structure. As the copolymerization method, any method such as solution polymerization, bulk polymerization, suspension polymerization, and emulsion polymerization can be selected.

The polyfunctional polymerization initiator (D) is a polyfunctional polymerization initiator having two or more peroxide groups in I.1 molecule, and one or more peroxide groups in II.1 molecule. And a polyfunctional polymerization initiator having one or more polymerizable unsaturated groups.

Examples of the polyfunctional polymerization initiator of the above I include 1,1-di-t
-Butylperoxy-3,3,5-trimethylcyclohexane, 1,3-bis- (t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5- (t-butylperoxy) hexane, 2 , 5-Dimethyl-2,5-di- (t-butylperoxy) hexyne-3, tris- (t-butylperoxy) triazine, 1,1-di-t-butylperoxycyclohexane, 2,2- Di-t-butylperoxybutane, 4,4-di-t-butylperoxyvaleric acid-n-butyl ester, di-t-butylperoxyhexahydroterephthalate, di-t-butylperoxyazelate, Di-t-butylperoxytrimethyl adipate, 2,2-bis- (4,4-di-t-butylperoxycyclohexyl) propane, 2,2-t-butylperoxyoctane and various polymer Ido, and the like.

Of these, preferred are 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane and 1,1-
Di-t-butylperoxycyclohexane, di-t-butylperoxyhexahydroterephthalate, di-t
-Butylperoxyazelate and 2,2-bis- (4,4-
Di-t-butylperoxycyclohexyl) propane.

As the polyfunctional polymerization initiator of the above II, diallyl peroxycarbonate, t-butyl peroxymaleic acid, t-butyl peroxyallyl carbonate and t-
Butyl peroxyisopropyl fumarate and the like can be mentioned.

Of these, preferred is t-butylperoxyallyl carbonate.

Solvents for obtaining the high molecular weight copolymer (A) by solution polymerization include cycloalkane solvents such as cyclohexane; aromatic solvents such as benzene, toluene, xylene, ethylbenzene and cumene; ethyl acetate, butyl acetate and the like. Ester-based solvents; ether-based solvents such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, etc. are used.

In particular, in order to increase the molecular weight of the high molecular weight copolymer (A), cycloalkane solvents and aromatic solvents are preferable among the above solvents.

In addition, when the high molecular weight copolymer (A) is obtained by suspension polymerization, an inorganic acid dispersant such as calcium carbonate or calcium phosphate, an organic dispersant such as polyvinyl alcohol or methylated cellulose is used, The monomer can be polymerized in water.

The copolymerization temperature of the high molecular weight copolymer (A) is usually 50 to 150.
C., preferably 60 to 120.degree. C., and the copolymerization is preferably carried out in an atmosphere of an inert gas such as nitrogen.

During the copolymerization of the high molecular weight copolymer (A), a polyfunctional monomer having two or more polymerizable double bonds is gelled in order to increase the molecular weight of the high molecular weight copolymer (A). May be added in such an amount that does not generate (0.1 mol% or less).

Examples of the polyfunctional monomer include di or polyvinyl compounds (divinylbenzene, divinyltoluene, ethylene glycol diacrylate, 1,6-hexanediol diacrylate, etc.) and the like.

Of these, preferably divinylbenzene and 1,6
-Hexanediol diacrylate.

At the time of producing the low molecular weight polymer (B), I. styrene or a styrene substitution product, II. Styrene or a styrene substitution product, and two or more kinds of monomers of acrylic acid esters and / or methacrylic acid esters. A monomer selected from the above is used alone, or a monomer and a polymerization initiator, or a monomer and a solution consisting of a polymerization initiator and a solvent is added dropwise, and a solution polymerization method is used for polymerization. .

As the above-mentioned polymerization initiator at the time of polymerizing the low molecular weight polymer (B), azo-based polymerization initiators such as azobisisobutyronitrile, azobisvaleronitrile and azobiscyanovaleric acid;
Organic peroxide-based polymerization initiators such as benzoyl peroxide, di-t-butyl peroxide, t-butyl peroxybenzoate and the like are used.

Preferably, azobisisobutyronitrile, di-t-
Butyl peroxide and t-butyl peroxybenzoate.

As the above-mentioned solvent at the time of polymerizing the low molecular weight polymer (B),
Cycloalkane-based solvents such as cyclohexane; benzene,
Aromatic solvents such as toluene, xylene, ethylbenzene and cumene; ester solvents such as ethyl acetate and butyl acetate; ether solvents such as methyl cellosolve and ethyl cellosolve are used.

Of these, toluene, xylene and ethylbenzene are preferable.

The polymerization temperature is usually 80 to 220 ° C., preferably 100 to 21.
It is preferably 0 ° C., and the polymerization is preferably carried out in an atmosphere of an inert gas such as nitrogen.

The intermediate molecular weight copolymer (C) is obtained by copolymerizing monomers in the presence of the high molecular weight copolymer (A) and the low molecular weight polymer (B) substantially without using a solvent. .

 The reason for the copolymerization as described above is as follows.

That is, even without a solvent, it is difficult to uniformly mix the high molecular weight copolymer (A) and the low molecular weight polymer (B) even in a molten state. For resins with poor uniformity, crush the resin,
When made into toner, the amount of over-pulverized toner increases,
In the subsequent classification step, the yield is lowered, and the dispersibility of the coloring material such as carbon black or the addition of the charge control agent in the toner is deteriorated, which causes a problem that the charging surface is adversely affected.

In the present invention, the monomer constituting the intermediate molecular weight copolymer (C) acts as a solvent before the polymerization, and the high molecular weight copolymer (A) and the low molecular weight polymer (B) are uniformly mixed. To help.

Further, in the present invention, in the presence of a high molecular weight copolymer (A) having a molecular weight higher than the critical molecular weight and a low molecular weight polymer (B) having a molecular weight lower than the critical molecular weight,
Since the intermediate molecular weight copolymer (C) having a molecular weight that exceeds the critical molecular weight is polymerized, the high molecular weight copolymer (A) and the low molecular weight polymer (B) are mixed more uniformly.

Therefore, in the present invention, when the resin is pulverized into a toner, the amount of the over-pulverized toner is reduced, which results in
In the subsequent classification step, the yield can be improved, and the dispersibility of the coloring material such as carbon black and the additives such as the charge adjusting agent in the toner can be improved, and there is no fear that the charging surface or the like is adversely affected.

The polymerization is usually carried out by thermal polymerization without using a polymerization initiator, but the polymerization may be carried out using a polymerization initiator. Examples of the polymerization initiator include a polyfunctional polymerization initiator (D) used for polymerization of the high molecular weight copolymer (A) or a low molecular weight polymer (B).
The same as the example of the polymerization initiator used for the polymerization of.

When manufacturing the binder of the present invention, first,
As described above, the high molecular weight copolymer (A) and the low molecular weight polymer (B) are separately polymerized and mixed in a solution state or a molten state. Thereafter, a monomer such as styrene or a substituted styrene or (meth) acrylic acid ester is added, and bulk polymerization is carried out to obtain a high molecular weight copolymer (A) and a low molecular weight polymer (B). In the presence of, the intermediate molecular weight copolymer (C) is polymerized to produce a binder.

In addition, after polymerizing the high molecular weight copolymer (A), in the presence of the high molecular weight copolymer (A) in a solution state or a molten state,
The monomer for low molecular weight polymer (B) is continuously or intermittently supplied to polymerize the low molecular weight polymer (B), and then the high molecular weight copolymer (A) and the low molecular weight polymer (B It is also possible to produce a binder by polymerizing the intermediate molecular weight copolymer (C) in the presence of (1).

The proportion of each monomer constituting the high molecular weight copolymer (A) is usually 98 to 50% by weight, preferably 95 to 60% by weight, of styrene or a styrene-substituted product, and (meth) acrylic acid. The ester is usually 2 to 50% by weight, preferably 5 to 40%.
% By weight, other monomers 0 to 10% by weight, preferably 0 to
It is 5% by weight.

In addition, the ratio of each monomer when polymerizing the low molecular weight polymer (B) is usually 70 to styrene or a styrene substitution product.
100% by weight, preferably 80-100% by weight, the (meth) acrylic acid ester is usually 0-30% by weight, preferably,
0 to 20% by weight, other monomers are usually 0 to 10% by weight, preferably 0 to 5% by weight.

Further, the proportion of each monomer constituting the intermediate molecular weight copolymer (C) is usually 60 to 60
95% by weight, preferably 70 to 90% by weight, (meth) acrylic acid ester is usually 5 to 40% by weight, preferably 10
-30% by weight, other monomers 0-10% by weight, preferably,
It is 0 to 5% by weight.

In the binder, the proportion of a portion having a molecular weight of 300,000 or more mainly derived from the high molecular weight copolymer (A) is usually 10 to 50 area%, preferably 15 to 45 area%.
If the portion having a molecular weight of 300,000 or more is less than 10 area%, it is difficult to obtain sufficient HO, and if it exceeds 50 area%, the MF becomes too high, which is not preferable.

In the binder, the proportion of the portion having a molecular weight of 1000 to 30,000 mainly derived from the low molecular weight polymer (B) is usually 35 to 90 area%, preferably 40 to 85 area%.
If the portion having a molecular weight of 1,000 to 30,000 is less than 50 area%, the MF becomes too high, and if it exceeds 90 area%, it is difficult to obtain sufficient HO, which is not preferable.

In the binder, the proportion of the portion having a molecular weight of 50,000 to 200,000 mainly derived from the intermediate molecular weight copolymer (C) is
Usually, it is 10 to 30 area%, preferably 12 to 25 area%. If the portion of the molecular weight of 50,000 to 200,000 is less than 10% by area, the coloring material such as carbon black and the additives such as the charge control agent are not uniformly dispersed. If it exceeds 30% by area, the weight average molecular weight and number The value of the ratio to the average molecular weight becomes small and the fixing temperature range becomes narrow, which is not preferable.

The area% is the area of a portion of the binder having a molecular weight of 300,000 or more, the area of a portion of 1,000 to 30,000, or the molecular weight of 50,000 to 50,000 on a gel permeation chromatography (hereinafter abbreviated as GPC) chart of the binder. This is the percentage of the total area of the area of 200,000 parts.

In addition, at the time of measurement by GPC, tetrahydrofuran is used as a solvent (hereinafter abbreviated as THF), and the measurement is performed at a temperature of 40 ° C. The measurement is carried out using standard polystyrene as a reference.

Further, the glass transition point (Tg) of the entire binder of the present invention
Is usually 40 to 80 ° C, preferably 45 to 70 ° C.
If the glass transition point (Tg) is less than 40 ° C, the storage stability of the toner will be poor, and if it exceeds 80 ° C, the MF will increase.
It is not preferable because it cannot be used practically as a toner.

The weight average molecular weight (w) of the binder of the present invention is usually 200,000 to 1,000,000, preferably 250,000 to 500,000.
If the weight average molecular weight is less than 200,000, it is difficult to obtain sufficient HO, and if it exceeds 1,000,000, the MF becomes too high, which is not preferable.

The weight average molecular weight is measured by GPC using THF as a solvent.

Molecular weight distribution of the binder of the present invention [value (w / n) of ratio of weight average molecular weight (w) and number average molecular weight (n)]
Displayed in] is usually 40 to 100, preferably 45 to 8
It is 0. If the molecular weight distribution is less than 40, the difference between MF and HO becomes small, which is not preferable. Further, if the molecular weight distribution is 100 or more, the production is difficult, which is not preferable.

Furthermore, in the binder of the present invention, in the dynamic viscoelastic property in a molten state at 150 ° C., the absolute value of complex viscosity | η * (20) | at a frequency of 20 Hz is 1000 to 15000 pois.
e, the absolute value of complex viscosity at 1Hz | η * (1) |
00 to 60,000 poise and the value of the ratio of the above absolute values | η
* (20) | / | η * (1) | is preferably 0.20 or less.

The reason for setting the dynamic viscoelastic properties as described above is as follows.

That is, the copying machine has a low speed machine (about 10 sheets / minute) to a high speed machine (about 70 sheets / minute). The higher the speed, the shorter the heating time of the toner and the smaller the amount of heat given to the toner. .

In this case, even if the amount of heat applied to the toner is small, if the viscosity of the toner does not decrease due to this amount of heat, the toner will not be fixed well on the paper or the like, and will not be compatible with high-speed machines.

By the way, in the copying machine, when the toner is fixed on the paper or the like by the heat roll, the toner receives shearing force by the heat roll and the press roll. In this case, the shear rate of the toner varies depending on the copy rate.

Therefore, in order to support from low speed machines to high speed machines, 150 ℃
In the melted state, the higher the shear rate that the toner receives, the lower the viscosity needs to be.

That is, in the binder of the present invention, the higher the shearing speed that the toner receives, the more the desired viscosity is set so that it can be applied to a wide range of copying speeds from low speed machines to high speed machines.

The proportion of the constituent components of the electrophotographic toner used as the binder of the present invention is such that the binder is usually 50 to 95% by weight, and known coloring materials (carbon black, iron black, benzidine yellow, quinacridone, rhodamine B, phthalocyanine). Etc.) is usually 5 to 10% by weight, and magnetic powder (iron,
Powders of ferromagnetic metals such as cobalt and nickel, or compounds such as magnetite, hematite, and ferrite) are usually 0 to 50% by weight.

Further, various additives [charge adjusting agent (metal complex, nigrosine, etc.), lubricant (polytetrafluoroethylene, low molecular weight polyolefin, fatty acid, or metal salt or amide thereof, etc.)] may be added to the toner. . The ratio of these additives in the toner is usually 0 to 5% by weight.

The electrophotographic toner is dry-blended with the above components, melt-kneaded, then coarsely pulverized, and finally atomized using a jet pulverizer or the like, further classified, and the particle size is 5 to 20 μm. It is obtained as fine particles of.

The electrophotographic toner is mixed with carrier particles such as iron powder, glass beads, nickel powder and ferrite, if necessary, and used as a developer for an electric latent image.
Further, hydrophobic colloidal silica fine powder may be added to the electrophotographic toner in order to improve the fluidity of the powder.

The electrophotographic toner is used by being fixed on a support (paper, polyester film, etc.), and as a fixing method, a known heat roll fixing method can be applied.

[Examples] Hereinafter, the present invention will be further described with reference to Examples, but the present invention is not limited to the Examples. In the examples, all parts are parts by weight.

The conditions for measuring the molecular weight by GPC are as follows.

Device: Tosoh Corp. HLC-802A column: Tosoh Corp. TSKge1GMH6 2 Measurement temperature: 40 ° C. Sample solution: 0.5 wt% THF solution Solution injection amount: 200 μl Detection device: Refractive index detector Molecular weight The calibration curve was created using standard polystyrene.

 The measurement conditions of dynamic viscoelasticity are as follows.

Equipment: Rheometrics Inc.U.
SA) RDS-7700II Dynamic Spectrometer Test Fixture: Use 25mmΦ cone plate Measurement temperature: 150 ℃ Measurement frequency: 20Hz (125.6rad / sec) and 1Hz (6.28rad / se)
c) Strain rate: 5% fixed (Comparative example 1) 1. Production of high molecular weight copolymer (A) In a 2 l glass autoclave, 450 parts of water and 2 parts of polyvinyl alcohol (PVA235 made by Kuraray Co., Ltd.) weight%
An aqueous solution (50 parts) was added, and a mixed solution of styrene (260 parts), n-butyl acrylate (76 parts) and lauroyl peroxide (1.3 parts) was added thereto, and the mixture was stirred to give a suspension.

After sufficiently replacing the inside of the autoclave with nitrogen, the temperature was raised to 80 ° C. to start polymerization. The polymerization was continued while maintaining the same temperature, and after 20 hours, the temperature was raised to 95 ° C. After the temperature was maintained at the same temperature for 2 hours, the temperature was further raised to 120 ° C. and the temperature was maintained for 1 hour to complete the suspension polymerization.

The obtained high molecular weight copolymer (TA-1) was filtered, washed with water,
When dried and analyzed, the weight average molecular weight (w) was
320,000, the content of the molecular weight of 300,000 or more is 31 area%, the content of the molecular weight of 50,000 to 200,000 is 45 area%, the molecular weight of 1000 to
The content of the 30,000 portion was 3 area%.

2. Manufacture of low molecular weight polymer (B) 600 parts of toluene was charged into a 2 l four-necked flask,
After thoroughly replacing the inside of the flask with nitrogen while stirring,
Toluene is heated to the boiling point (about 110 ° C.) and refluxed.

Under this reflux, a mixed solution of 920 parts of styrene, 80 parts of n-butyl acrylate, and 90 parts of azobisisobutyronitrile was evenly dropped into the flask over 4 hours.

Further, under the reflux of toluene, a solution of 300 parts of toluene and 10 parts of azobisisobutyronitrile was dropped into the flask over 1 hour to complete the polymerization, and a solution containing a low molecular weight polymer (TA-2 ) Got. This solution was dried under reduced pressure to obtain a low molecular weight polymer (TA-3).

When the obtained low molecular weight polymer (TA-3) was analyzed, the weight average molecular weight (w) was 8,000, the content of the portion having a molecular weight of 300,000 or more was 0 area%, and the content of the portion having a molecular weight of 50,000 to 200,000 was contained. The amount is 1 area% and the content of the part of molecular weight 1000 to 30,000 is 90
The area was%.

3. Manufacture of binder High molecular weight copolymer (TA-1) in a 2-liter 4-necked flask.
Solution containing 333 parts and low molecular weight polymer (TA-3) (TA-
2) 1334 parts was added, and the inside of the flask was sufficiently replaced with nitrogen, and then the temperature was raised to reflux toluene. Under this reflux, the high molecular weight copolymer (TA-1) was dissolved and then dried under reduced pressure to obtain a binder (TA-4).

GPC measurement and glass transition point (Tg) measurement of the obtained binder (TA-4) revealed that the content of the portion having a molecular weight of 300,000 or more was 9% by area, and the molecular weight was 50,000 to 20.
The content of 10,000 parts is 15 area%, the content of the parts of molecular weight 1000 to 30,000 is 60 area%, the weight average molecular weight (w) is 120,000,
The value (w / n) of the ratio between the weight average molecular weight (w) and the number average molecular weight (n) was 21, and the Tg was 59 ° C.

Also, regarding the obtained binder (TA-4), 150 ° C
When the dynamic viscoelasticity at 20Hz was measured, the absolute value of complex viscosity | η * (20) | was 650poise and the absolute value of complex viscosity at 1Hz | η * (1) | was 2600poise. , The value of the ratio of the above absolute values | η * (20) | / | η * (1) |
Was 0.25.

(Comparative Example 2) 1. Production of high molecular weight copolymer (A) By the same method as the production method of the high molecular weight copolymer (TA-1) of Comparative Example 1, the high molecular weight copolymer (TB-1) was prepared. ) Got. The difference from the production method of Comparative Example 1 is that instead of the polymerization initiator lauroyl peroxide having a monofunctional structure, 2
This is the point of using a polymerization initiator having a functional structure, 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane.

The obtained high molecular weight copolymer (TB-1) was separated by filtration, washed with water,
When dried and analyzed, the weight average molecular weight (w) was
850,000, 79% by area of molecular weight of 300,000 or more, molecular weight of 50,000-
The content of the 200,000 part was 13 area%, and the content of the part having a molecular weight of 1,000 to 30,000 was 0 area%.

2. Production of binder A binder (TB-4) was obtained by performing substantially the same operation as in the production method of the binder of Comparative Example 1.

GPC measurement and glass transition point (Tg) measurement of the obtained binder (TB-4) revealed that the content of the portion having a molecular weight of 300,000 or more was 26% by area, and the molecular weight was 50,000 to 20.
The content of 10,000 parts is 5 area%, the content of parts of molecular weight 1000 to 30,000 is 60 area%, the weight average molecular weight (w) is 250,000,
The value (w / n) of the ratio between the weight average molecular weight (w) and the number average molecular weight (n) was 60, and the Tg was 60 ° C.

Moreover, about the obtained binder (TB-4), 150 ° C
When the dynamic viscoelasticity at the frequency of 20Hz was measured, the absolute value of complex viscosity | η * (20) | was 3600poise and the absolute value of complex viscosity at 1Hz | η * (1) | was 23000poise. , The value of the ratio of the above absolute values | η * (20) | / | η * (1) |
Was 0.16.

(Comparative Example 3) 1. Production of high molecular weight copolymer (A) In a glass flask of 1, 450 parts of water, 2 wt% aqueous solution of polyvinyl alcohol (PVA235 manufactured by Kuraray Co., Ltd.)
Add 50 parts, and add 750 parts of styrene and n-acrylic acid.
A mixed solution of 250 parts of butyl and 2 parts of di-t-butylperoxyhexahydroterephthalate was added and stirred,
It was a suspension.

After sufficiently replacing the inside of the flask with nitrogen, the temperature was raised to 85 ° C. to start polymerization. Hold the same temperature to continue the polymerization, and after 8 hours, confirm that the conversion rate exceeded 70%,
The temperature was raised to 95 ° C and the suspension polymerization was completed after 4 hours to obtain a high molecular weight copolymer (TC-1).

The obtained high molecular weight copolymer (TC-1) was separated by filtration, washed with water,
When dried and analyzed, the weight average molecular weight (w) was
560,000, 61 area% of the part with a molecular weight of 300,000 or more, molecular weight of 50,000-
The content of the 200,000 portion was 23 area%, and the content of the portion having a molecular weight of 1,000 to 30,000 was 0 area%.

2. Manufacture of Binder Into the stainless steel autoclave of 1 was charged 450 parts of the above high molecular weight copolymer (TC-1) and 550 parts of xylene,
After fully replacing the inside of the autoclave with nitrogen, seal it,
The temperature was raised to 200 ° C.

Then, while maintaining the temperature of 200 ℃, in the autoclave,
A mixed solution consisting of 420 parts of styrene, 100 parts of methyl acrylate, and 40 parts of n-butyl acrylate was uniformly added dropwise over 8 hours, and the mixture was kept at the same temperature for 3 hours to complete the polymerization, and the binder ( TC-4) was obtained.

GPC measurement and glass transition point (Tg) measurement of the obtained binder (TC-4) revealed that the content of the portion having a molecular weight of 300,000 or more was 27 area% and the molecular weight was 50,000 to 20.
The content of 10,000 parts is 8 area%, the content of parts of molecular weight 1000 to 30,000 is 50 area%, the weight average molecular weight (w) is 330,000,
The value (w / n) of the ratio between the weight average molecular weight (w) and the number average molecular weight (n) was 55, and the Tg was 62 ° C.

Also, regarding the obtained binder (TC-4), 150 ° C
Dynamic viscoelasticity was measured at a frequency of 20 Hz, the absolute value of complex viscosity | η * (20) | was 4000 poise, and the absolute value of complex viscosity at 1 Hz | η * (1) | was 30,000 poise. And the value of the ratio of the above absolute values | η * (20) | / | η * (1) |
Was 0.13.

(Example 1) The binder of Comparative Example 2 (TB
-4) 600 parts, styrene 330 parts, n-butyl acrylate 70
And 0.2 part of 1,6-hexanediol diacrylate were added.

After thoroughly replacing the inside of the flask with nitrogen, the temperature was raised while sealing with nitrogen and the polymerization was carried out at 110 ° C. for 2 hours. After that, the temperature was raised to 120 ° C, the polymerization was carried out at the same temperature for 10 hours, and the polymerization was continued for 19 hours in 3 hours.
The temperature was raised to 0 ° C. and maintained at the same temperature for 2 hours to complete the polymerization to obtain the binder (TE-4) of the present invention.

GPC measurement and glass transition point (Tg) measurement of the obtained binder (TE-4) revealed that the content of the portion having a molecular weight of 300,000 or more was 25 area% and the molecular weight was 50,000 to 20.
The content of 10,000 parts is 15 area%, the content of parts of molecular weight 1000 to 30,000 is 49 area%, the weight average molecular weight (w) is 280,000,
The value (w / n) of the ratio between the weight average molecular weight (w) and the number average molecular weight (n) was 63, and the Tg was 59 ° C.

Also, regarding the obtained binder (TE-4), 150 ° C
When the dynamic viscoelasticity at the frequency of 20 Hz was measured, the absolute value of complex viscosity | η * (20) | was 4400 poise, and the absolute value of complex viscosity at 1 Hz | η * (1) | was 32000 poise. , The value of the ratio of the above absolute values | η * (20) | / | η * (1) |
Was 0.14.

(Example 2) The binder of Comparative Example 3 (TB
-4) 800 parts, styrene 165 parts, n-butyl acrylate 35
A mixed solution consisting of parts was added.

After sufficiently replacing the inside of the flask with nitrogen, the temperature was raised while sealing with nitrogen and the polymerization was carried out at 130 ° C. for 4 hours. Then, the temperature was raised to 190 ° C. in 3 hours and the temperature was maintained for 2 hours to complete the polymerization, and thus the binder (TF-4) of the present invention was obtained.

GPC measurement and glass transition point (Tg) measurement of the obtained binder (TF-4) revealed that the content of the portion having a molecular weight of 300,000 or more was 23 area% and the molecular weight was 50,000 to 20.
The content of 10,000 parts is 23 area%, the content of parts of molecular weight 1000 to 30,000 is 48 area%, the weight average molecular weight (w) is 260,000,
The value (w / n) of the ratio between the weight average molecular weight (w) and the number average molecular weight (n) was 43, and the Tg was 58 ° C.

Moreover, about the obtained binder (TF-4), 150 ° C
When the dynamic viscoelasticity at the frequency of 20Hz was measured, the absolute value of complex viscosity | η * (20) | was 2600poise and the absolute value of complex viscosity at 1Hz | η * (1) | was 15000poise. , The value of the ratio of the above absolute values | η * (20) | / | η * (1) |
Was 0.17.

(Example 3) In a 2 l four-necked flask, 400 parts of the high molecular weight copolymer (TA-3) of Comparative Example 1, 480 parts of styrene, 120 parts of n-butyl acrylate, 0.6 part of divinylbenzene, and 2 , 2-bis-
A mixture of 0.3 parts of (4,4-di-t-butylperoxycyclohexyl) propane was added.

After sufficiently replacing the inside of the flask with nitrogen, the temperature was raised to 95 ° C., polymerization was carried out at the same temperature for 8 hours, and further the temperature was raised to 120 ° C. and polymerization was carried out for 2 hours.

When this was sampled and analyzed, the conversion rate
75%, the content of the part with a molecular weight of 300,000 or more is 60 area%, the content of the part with a molecular weight of 50,000 to 200,000 is 10 area%, the molecular weight is 1000-
The content of the 30,000 portion was 0 area%.

Furthermore, di-t-butyl peroxide was placed in the flask.
0.6 part was added, the temperature was raised to 180 ° C. over 3 hours, and the temperature was maintained for 2 hours to complete the polymerization to obtain the binder (TG-4) of the present invention.

The obtained binder (TG-4) was measured by GPC and the glass transition point (Tg). As a result, the content of the portion having a molecular weight of 300,000 or more was 26 area% and the molecular weight was 50,000 to 20.
The content of 10,000 parts is 15 area%, the content of the parts of molecular weight 1000 to 30,000 is 50 area%, the weight average molecular weight (w) is 280,000,
The value (w / n) of the ratio between the weight average molecular weight (w) and the number average molecular weight (n) was 62, and the Tg was 60 ° C.

Also, regarding the obtained binder (TE-4), 150 ° C
When the dynamic viscoelasticity at the frequency of 20Hz was measured, the absolute value of complex viscosity | η * (20) | was 5000poise, and the absolute value of complex viscosity at 1Hz | η * (1) | was 36000poise. , The value of the ratio of the above absolute values | η * (20) | / | η * (1) |
Was 0.14.

(Use Examples I to III and Comparative Use Examples IV to VI) The binders of the present invention of Examples 1 to 3 and Comparative Examples 1 to 1
Carbon binder (MA100 manufactured by Mitsubishi Kasei Co., Ltd.) 7 parts, low molecular weight polypropylene (Viscole 550P manufactured by Sanyo Kasei Co., Ltd.) 3 parts, and charge control agent (Hodogaya Chemical ( Manufactured by Spiron Black TRH)
After uniformly mixing 2 parts, this was kneaded with a twin-screw extruder having an internal temperature of 150 ° C. After cooling this kneaded material, it was finely pulverized by a jet pulverizer and classified by a dispersion separator to obtain toners (I to VI) having an average particle diameter of 12 μ.

(Test Example 1) A test material was prepared by uniformly mixing 97 parts of a ferrite carrier (EFV200 / 300 manufactured by Nippon Milling Co., Ltd.) with 3 parts of each of the toners (I to VI).

Further, a commercially available copying machine (BD-7720 manufactured by Toshiba Corp.) was modified to provide a fixing device having a variable fixing speed, and the fixing test of the above test materials was performed by the fixing device.

Furthermore, at a copy speed of 40 A4 sheets per minute, 30
A fixing test of 00 sheets was carried out, and it was checked whether or not toner was scattered.

 The test results are shown in Table 1.

As shown in Table 1, toners (I to III) using the binders (TD-4) to (TF-4) of Examples 1 to 3 of the present invention.
Are binders (TA-4) to (TA-4) of Comparative Examples 1 to 3.
In comparison with the toners (IV to VI) using No. 3, the temperature range between MF and HO is wider, the dependence on the copying speed is smaller, and the toner has favorable thermal characteristics.

(Effect of the invention) The binder of the present invention is a binder composed of a polymer having a wide molecular weight distribution, which has favorable characteristics in terms of HO and MF (low MF and high HO), and at the same time It is effective as a binder for electrophotographic toner that has a small dependence and can handle a wide range of copying speeds.

In addition, since the intermediate molecular weight copolymer was obtained by copolymerizing the monomers in the presence of the high molecular weight copolymer and the low molecular weight polymer, substantially without using a solvent, the intermediate molecular weight copolymer The monomers constituting the coalescence act as a solvent before the polymerization, and help the uniform mixing of the high molecular weight copolymer and the low molecular weight polymer.

Further, in the presence of a high molecular weight copolymer having a molecular weight higher than the critical molecular weight at which entanglement of molecules starts and a low molecular weight polymer having a molecular weight lower than the critical molecular weight, an intermediate molecular weight copolymer having a molecular weight crossing the critical molecular weight is polymerized. Therefore, the high molecular weight copolymer and the low molecular weight polymer are more uniformly mixed.

Therefore, in the present invention, when the resin is pulverized into a toner, the amount of the over-pulverized toner is reduced, which results in
In the subsequent classification step, the yield can be improved, and the dispersibility of the coloring material such as carbon black and the additives such as the charge adjusting agent in the toner can be improved, and there is no fear that the charging surface or the like is adversely affected.

Claims (2)

[Claims] 1. A high molecular weight copolymer (A) containing a portion having a molecular weight of 300,000 or more in (a) I. molecular weight distribution, and a low molecular weight polymer containing a portion having a molecular weight of 1,000 to 30,000 in II. The compound (B) and III. The intermediate molecular weight copolymer (C) containing a portion having a molecular weight of 50,000 to 200,000 in the molecular weight distribution, and having a weight average molecular weight of 200,000 to 1,000,000 and a weight average molecular weight of The value of the ratio of the average molecular weight to the number average molecular weight is 40 to 100
And (b) the monomers constituting the high molecular weight copolymer (A) and the intermediate molecular weight copolymer (C) are, respectively, I. styrene or a styrene substitute, and II. Two or more kinds of acrylic acid ester and / or methacrylic acid ester, and (c) the monomer constituting the low molecular weight polymer (B) is I. styrene or a styrene substitution product, and II. Styrene. Or a styrene substitution product and two or more kinds of monomers of acrylic acid esters and / or methacrylic acid esters, and (d) the high molecular weight copolymer (A) is a polyfunctional polymerization initiator. In the presence of (D), it is assumed that the monomers are copolymerized, and (e) the polyfunctional polymerization initiator (D) is a polymer having two or more peroxide groups in I.1 molecule. Functional polymerization initiator, II.1 one or more peroxide groups in the molecule, Selected from a polyfunctional polymerization initiator having one or more polymerizable unsaturated groups, (f) the intermediate molecular weight copolymer (C), the high molecular weight copolymer (A) and the low molecular weight polymer (B). The toner binder for electrophotography, characterized in that it is obtained by copolymerizing monomers in the presence of (1) without substantially using a solvent. 2. Absolute value of complex viscosity at a frequency of 20 Hz in dynamic viscoelastic characteristics in a molten state at 150 ° C.
Let η * (20) | be 1000 to 15000 poise, the absolute value of complex viscosity at 1 Hz | η * (1) | be 5000 to 60,000 poise, and the ratio of the above absolute values | η * (20) | / | η *
(1) | is 0.20 or less, The toner binder for electrophotography according to claim 1, characterized in that.