JP2800026B2 - Method for producing binder resin for toner and toner for developing electrostatic images - Google Patents

Description

The present invention relates to a binder resin used in a toner for developing an electrostatic latent image formed in an electrophotographic method, an electrostatic printing method, an electrostatic recording method, or the like. The present invention relates to a production method and an electrostatic image developing toner containing the binder resin.

[Prior Art] For example, in an electrophotographic method, an electrostatic latent image is generally formed by charging and exposing an electrostatic image carrier made of a photoconductive photoreceptor, and then this electrostatic latent image is made of a resin. The toner is developed with fine particles formed by adding a colorant or the like to a binder, and the obtained toner image is transferred to a support such as transfer paper and fixed to form a visible image.

In order to obtain a visible image as described above, it is necessary to fix a toner image. Conventionally, a heat roller fixing method which has high thermal efficiency and can perform high-speed fixing has been widely used.

However, recently, the miniaturization and the speeding up of the copying machine have been advanced, (a) suppressing the overheating deterioration of the copying machine, (b) preventing the heat deterioration of the photoconductor, and (c) operating the fixing device. To shorten the warm-up time required to raise the temperature to a temperature at which the heat roller can be fixed, and (d) reduce the temperature drop of the heat roller due to the heat absorbed by the transfer paper to continuously perform the heat roller many times. Due to the demand for enabling copying and (e) increasing thermal safety, the power consumption of the fixing heater has been reduced and the fixing process can be performed with the temperature of the heat roller lowered. Is strongly required. Therefore, it is necessary that the toner can be well fixed at a low temperature.

In addition, the toner needs to be able to stably exist as a powder without agglomeration under the conditions of use or storage environment, that is, to have excellent blocking resistance. In the case of the offset phenomenon, a part of the toner constituting the image is converted to the surface of the heat roller at the time of fixing, and this phenomenon is likely to be re-transferred to the next transfer paper to be contaminated. It is necessary to provide performance for preventing the occurrence of the offset phenomenon, that is, to impart offset resistance.

For this reason, conventionally, for example, JP-A-63-27855 discloses a crystalline polyester and Mw / Mn ≧ 3.
(5) A toner containing a block copolymer or a graft copolymer with an amorphous vinyl polymer described in
No. 856 discloses a toner containing a block copolymer or a graft copolymer of a crystalline polyester and an amorphous vinyl polymer having two or more peaks in a molecular weight distribution. Also, JP-A-64-35455 discloses that
An image forming method using a toner containing a block copolymer or a graft copolymer of a crystalline polyester and an amorphous vinyl polymer is disclosed in JP-A-64-35456. A method for producing a toner containing a block copolymer or a graft copolymer with a functional vinyl polymer and adding a heat treatment step is disclosed.

Japanese Patent Application Laid-Open No. 62-81644 discloses a copolymer obtained by blending an unsaturated monomer in a specific blending ratio in the presence of a fluorine-containing resin having a reactive double bond and polymerizing the unsaturated monomer. Is disclosed.

[Problems to be Solved by the Invention] In each of the above-mentioned conventional techniques, in order to obtain a block copolymer or a graft copolymer, specifically, p-toluenesulfonic acid (ester bond), hexamethylene diisocyanate (urethane bond) ) Or heat (amide bond,
A crystalline polyester and an amorphous (non-crystalline) vinyl polymer are chemically bonded by utilizing a reaction based on an epoxy group.

However, in the reaction with p-toluenesulfonic acid and heat, the block ratio or graft ratio, which is the bonding ratio of the crystalline polyester to the amorphous vinyl polymer, was low, and the low-temperature fixability was insufficient. This is considered to be because unreacted crystalline polyesters aggregate with each other to form large domains, and even if a local decrease in viscosity occurs during heating, the viscosity of the entire toner particles does not decrease. . Further, the fluidity of the toner particles is low because large domains of the crystalline polyester component are formed in the toner particles.
In addition, in the reaction using isocyanate, a coupling bond between —OH groups at molecular terminals is generated, and the reaction proceeds at random, so that the blocking ratio or the grafting ratio also decreases. Further, when a reaction between crystalline polyesters occurs, there is a disadvantage that macromolecules are formed and pulverizability is reduced.

Further, since the above-mentioned technology uses a fluorine-containing resin, there is a drawback that, depending on its content and type, the negative (negative) chargeability is too strong to obtain an image density, and further, the pulverizability and the fixability are poor. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems.
The object of the present invention is to provide a method for increasing the block ratio or the graft ratio in a block copolymer or a graft copolymer of a crystalline polyester and an amorphous vinyl polymer. A toner binder resin having better low-temperature fixability and good anti-offset property by increasing the toner ratio.
The fourth object is to provide a toner binder resin having good pulverizability, the fourth object is to provide a toner having good fluidity and good agglomeration resistance, and the fifth object is to provide a toner according to environmental conditions. It is an object of the present invention to provide a toner whose characteristics are not affected and in which the chargeability, fluidity and developability are constant even under high temperature and high humidity conditions and good image quality can be obtained.

Means for Solving the Problems In order to achieve the above object, a method for producing a binder resin for a toner according to the present invention comprises a method for producing a vinyl monomer in the presence of a crystalline polyester having an unsaturated double bond at a molecular terminal. Is polymerized to obtain a block copolymer or a graft copolymer having a ratio Mw / Mn of the number average molecular weight Mn to the weight average molecular weight Mw of 3.5 or more. Further, the electrostatic developing toner of the present invention has a number average molecular weight Mn and a weight average molecular weight Mw obtained by polymerizing a vinyl monomer in the presence of a crystalline polyester having an unsaturated double bond at a molecular terminal. Characterized in that a block copolymer or a graft copolymer having a ratio Mw / Mn of 3.5 or more is contained as a binder resin.

 Hereinafter, the present invention will be described in detail.

The crystalline polyester used in the present invention is not particularly limited, but a polyalkylene polyester is particularly preferable from the viewpoint of low-temperature fixability and fluidity. Specific examples of such a polyalkylene polyester include, for example, polyester sebacate, polyethylene adipate, polyethylene suberate, polyethylene succinate, polyethylene-p- (carbophenoxy) undecaate, polyhexamethylene oxalate, and polyhexahethylene sebacate. , Polyhexamethylene decanedioate, polyoctamethylene dodecanedioate, polynonamethylene azelate, polydecamethylene adipate, polydecamethylene azelate, polydecamethylene oxalate, polydecamethylene sebacate, polydecamethylene succinate , Polydecamethylene dodecandioate, polydecamethylene octadecanedioate, polytetramethylene sebacate, polytrimethylene dodecandioate, polytrimethylene Chi Ren octadecane dioate, polytrimethylene Ok The rate, polyhexamethylene - decamethylene - sebacate, polyoxyethylene decamethylene-2-methyl -
1,3-propane-dodecandioate and others can be mentioned.

There are various methods for introducing an unsaturated double bond into the molecular terminal of such a crystalline polyester, and there is no limitation.For example, these functional groups may be used by utilizing a carboxyl group or a hydroxyl group at the molecular terminal of the crystalline polyester. And a vinyl monomer having a functional group capable of reacting with the monomer is chemically bonded to be introduced. Specifically, after the completion of the synthesis of the crystalline polyester, the carboxyl group at the molecular terminal is added with a vinyl monomer in an amount equivalent to the hydroxyl group, ester condensation, amide condensation,
A crystalline polyester having an unsaturated double bond at a molecular terminal is obtained by an epoxy reaction or the like.

In order to efficiently insert unsaturated double bonds at the molecular ends,
It is preferable that the crystalline polyester is purified by a precipitation purification method or a column chromatography method, and is reacted after removing unreacted raw materials, glycol and dicarboxylic acid.

Carboxyl groups are monomers having a functional group that reacts with hydroxyl groups, such as acrylic acid, β, β-dimethylacrylic acid, α-ethylacrylic acid, methacrylic acid, fumaric acid,
Itaconic acid, maleic acid, crotonic acid, hydroxyethyl methacrylate, acryloyloxyethyl monophthalate, acryloyloxyethyl monosuccinate,
Examples include N-hydroxyethyl acrylamide, N-hydroxyethyl methacrylamide, N-methylol acrylamide, p-aminostyrene, glycidyl methacrylate, and others.

The crystalline polyester has a melting point Tm of 50 to 120.
C., preferably in the range of 50-100.degree. When the melting point Tm of the crystalline polyester used is less than 50 ° C., the obtained toner has poor blocking resistance, and
If the temperature exceeds 120 ° C., the melt fluidity of the toner at a low temperature is reduced, and the fixing property is deteriorated. In addition, the melting point Tm of the crystalline polyester means the melting point of the crystalline polyester in a state not polymerized with the vinyl monomer.

The melting point of the crystalline polyester can be measured by, for example, “DSC-20” (manufactured by Seiko Instruments Inc.) in accordance with the differential scanning calorimetry (DSC). The measurement conditions are as follows. / min) is defined as the melting peak value when heated.

This crystalline polyester has a weight average molecular weight Mw.
It is preferable that the number average molecular weight Mn is 2,000 to 20,000, and the number average molecular weight Mn is 2,000 to 20,000. When the molecular weight is in this range, the offset resistance of the toner and the pulverization efficiency in the production of the toner are further improved.

The vinyl monomers used to obtain the copolymer of the present invention include olefins and derivatives thereof, dienes and derivatives thereof, vinyl acetylenes, acrylic acid and methacrylic acid and derivatives thereof, acrylic esters, methacrylic esters And acrylamide and methacrylamide and derivatives thereof, acrylonitrile and methacrylonitriles, vinyl esters, vinyl ketone and derivatives thereof, vinyl ethers and styrene and derivatives thereof. Among them, styrene and its derivatives, acrylates and methacrylates are preferable, for example, styrene, o-methylstyrene, m-methylstyrene,
p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, methyl Acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, stearyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, Examples include stearyl methacrylate, cyclohexyl methacrylate, dimethylaminoethyl methacrylate, and the like. These monomers can be used alone or as a mixture of several kinds.

Of the vinyl monomers to be used, it is more preferable to use 50 to 95% by weight of a styrene derivative and 5 to 50% by weight of an acrylate or methacrylate. Excellent in offset resistance.

The copolymer according to the present invention is obtained by polymerizing the vinyl monomer in the presence of the crystalline polyester having an unsaturated double bond at the molecular terminal.

The proportion of the crystalline polyester used is such that the proportion of the crystalline polyester component in the block copolymer or the graft copolymer with the vinyl monomer is 3 to 50.
% By weight, preferably 5 to 40% by weight. When this ratio is less than 3% by weight, the toner obtained has a high minimum fixing temperature, and when it exceeds 50% by weight, the melt elasticity at the time of fixing becomes small and the offset resistance deteriorates.

As the polymerization method, any known technique can be used.

The block ratio or graft ratio of the obtained copolymer is
It refers to the ratio of the crystalline polyester at the time of preparation, which actually reacted with the vinyl monomer to form a block copolymer or a graft copolymer. As a method of actually calculating, there are various modes and there is no particular limitation, for example,
A calculation method by ¹ H-NMR can be adopted. Measure the ratio of the signal intensity of the unsaturated double bond bonded to the molecular end with the crystalline polyester to the signal intensity of the methylene group in the main chain, and calculate from the reduction ratio before and after the block reaction or the graft reaction. Can be.

Block rate or graft rate is at least 50% or more,
Preferably at least 75% is required and can be achieved by the method of the present invention.

In the obtained copolymer, the value of the ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn needs to be 3.5 or more, and particularly preferably 4 to 40. When the ratio Mw / Mn is too small, sufficient offset resistance and durability cannot be obtained.
Here, the values of the weight average molecular weight Mw and the number average molecular weight Mn can be obtained by various methods, and there are some differences due to the difference in the measurement methods, but in the present invention, the values are obtained by the following measurement methods. is there.

That is, the weight average molecular weight M was measured by gel permeation chromatography (GPC) under the conditions described below.
Measure w, number average molecular weight Mn, and peak molecular weight. Temperature 40
At a temperature of ° C., a solvent (tetrahydrofuran) is allowed to flow at a flow rate of 1.2 ml / min, and 3 mg of a tetrahydrofuran test solution having a concentration of 0.2 g / 20 ml is injected as a sample weight for measurement. In the measurement of the molecular weight of the sample, a measurement condition in which the logarithm of the molecular weight and the count number of a calibration curve prepared by using several kinds of monodisperse polystyrene standard samples are included in a linear range is selected. Note that the reliability of the measurement results was determined using the NBS706 polystyrene standard sample (weight average molecular weight Mw = 28.8 × 10 ⁴ , number average molecular weight Mn = 13.7) measured under the above measurement conditions.
× 10 ⁴ , Mw / Mn = 2.11) The ratio Mw / Mn is 2.11 ± 0.10.

As the GPO column to be used, any column may be employed as long as the above conditions are satisfied. Specifically, for example, TSK-GEL, GMH (manufactured by Toyo Soda Co., Ltd.) or the like can be used. The solvent and the measurement temperature are not limited to the above conditions, and may be changed to other conditions as appropriate.

From the viewpoint of further improving low-temperature fixability and offset resistance, the copolymer according to the present invention preferably has at least two or more maximum values in the molecular weight distribution. That is, it has a molecular weight distribution divided into at least two groups of a low molecular weight component and a high molecular weight component, and in a molecular weight distribution curve measured by gel permeation chromatography (GPC), at least one maximum value is 2 × 10 It is preferred to have at least two maxima such that they lie in the range ^{3 to} 2 × 10 ⁴ and at least one maxima lies in the range 1 × 10 ⁵ to 1 × 10 ⁶ .

The glass transition point of the obtained copolymer is preferably from 40 to 85 ° C, particularly preferably from 40 to 65 ° C. Here, the glass transition point is Tg, a value measured based on differential scanning calorimetry (DSC), and specifically, for example, using "DSC-20" (manufactured by Seiko Instruments Inc.) When measured at a rate of 10 ° C./min, it refers to the temperature at the intersection of the extension of the baseline below the glass transition point and the tangent that indicates the maximum slope from the peak rising portion to the peak apex.

The softening point of the copolymer is preferably from 85 to 150 ° C, particularly preferably from 85 to 130 ° C. The softening point was measured at 20 kg / c with a plunger while heating a 1 cm ² sample at a heating rate of 6 ° C./min using a Koka type flow tester (manufactured by Shimadzu Corporation).
A nozzle having a diameter of 1 mm and a length of 1 mm was pushed out by applying a load of m ² , whereby a plunger descent amount-temperature curve (softening flow curve) of the flow tester was drawn. Where the temperature corresponding to h / 2 is the softening point.

In the toner of the present invention, the copolymer obtained by the method of the present invention is used as a binder resin.

In such a toner, since the binder contains the above-described copolymer having a high graft ratio or high block ratio, low-temperature fixability by the crystalline polyester component and good wettability during melting can be obtained. As a result, the amorphous vinyl polymer component, which itself contributes to low-temperature fixability, exhibits offset resistance, and as a result, in forming a visible image by an electrostatic image, the offset resistance and low-temperature fixability are good. A wide fixing temperature range is obtained, and the blocking resistance and the fluidity are good, and an excellent visible image can be formed many times.

In the toner of the present invention, it is necessary that the copolymer obtained by the above-described method of the present invention is contained in an amount of at least 30% by weight or more, preferably 50 to 100% by weight.

The toner of the present invention contains a colorant in a binder composed of the specific copolymer as described above,
Further, if necessary, a magnetic substance and a specific improver may be contained in the resin.

Examples of the coloring agent include carbon black, nigrosine dye (CINo. 50415B), aniline blue (C.
I.No.50405), Calco Oil Blue (CINo.azoic Blu)
e3), Chrome Yellow (CINo. 14090), Ultramarine Blue (CINo. 77103), Dupont Oil Red (C.
I.No.26105), Quinoline Yellow (CINo.47005), Methylene Blue Chloride (CINo.52015), Phthalocyanine Blue (CINo.74160), Malachite Green Oxalate (CINo.42000), Lamp Black (CINo.7)
7266), Rose Bengal (CINo. 45435), mixtures thereof, and the like. The amount of the coloring agent is usually 0.1 to 20 parts by weight based on 100 parts by weight of the toner,
0.5 to 10 parts by weight is preferred.

As the magnetic material, ferrite, magnetite or other iron, cobalt, nickel or other ferromagnetic metal or alloy or a compound containing these elements, or a ferromagnetic element that does not contain a ferromagnetic element but is subjected to an appropriate heat treatment Alloy that shows manganese-copper-
An alloy of a type called a Heusler alloy containing manganese and copper, such as aluminum, manganese-copper-tin, chromium dioxide, and the like can be given. For example, when obtaining a black toner, magnetite, which is itself black and also functions as a colorant, can be particularly preferably used. When a color toner is to be obtained, it is preferable to use a material having less blackness such as metallic iron. Some of these magnetic materials also function as a colorant, and in such a case, they may also be used as a colorant. These magnetic materials have, for example, an average particle size.
It is uniformly dispersed in the resin in the form of fine powder of 0.1 to 1 μm. When the magnetic toner is used, the content is 100 to 20 parts by weight, preferably 40 to 70 parts by weight.

Examples of the property improver include a fixability improver, a charge control agent, and others.

Examples of the fixability improver include polyolefin, fatty acid metal salt, fatty acid ester and fatty acid ester wax, partially saponified fatty acid ester, higher fatty acid, higher alcohol, fluid or solid paraffin wax, polyamide wax, polyhydric alcohol ester, Silicon varnish, aliphatic fluorocarbon, or the like can be used. Particularly, a wax having a softening point (ring and ball method JIS K2531) of 60 to 150 ° C is preferable.

As the charge control agent, a conventionally known charge control agent can be used, and examples thereof include a nigrosine dye and a metal-containing dye.

Further, the toner of the present invention is preferably used by mixing inorganic fine particles such as a fluidity improver.

As the inorganic fine particles used in the present invention,
Primary particle size is 5mμ ~ 2μm, preferably 5mμ ~ 50
Particles that are 0 μm. The specific surface area by the BET method is 20
It is preferable that the ~500m ^2. The proportion mixed with the toner is 0.01 to 5% by weight, preferably 0.01 to 2.0% by weight. Examples of such inorganic fine powder include silica fine powder, alumina, titanium oxide, barium titanate,
Magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, silica lime, diatomaceous earth, chromium oxide, cerium oxide, red iron oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, carbonic acid Examples thereof include barium, calcium carbonate, silicon carbide, and silicon nitride, and silica fine powder is particularly preferable.

The silica fine powder referred to here is a fine powder having a Si—O—Si bond, and includes both those produced by a dry method and a wet method. Also, other than anhydrous silicon dioxide, aluminum silicate, sodium silicate, potassium silicate, magnesium silicate, zinc silicate and the like may be any,
Those containing at least 85% by weight of SiO ₂ are preferred.

Specific examples of these silica fine powders include various commercially available silicas, and those having a hydrophobic group on the surface are preferable. For example, AEROSIL R972, R-974, R-805, R-812
(Manufactured by Aerosil) and Tarax 500 (manufactured by Tarco). In addition, a silica fine powder treated with a silane coupling agent, a titanium coupling agent, silicon oil, silicon oil having an amine in a side chain, or the like can be used.

To give an example of a preferred method for producing the toner of the present invention,
First, a binder resin or a resin to which a toner component such as a coloring agent is added as required is melt-kneaded by, for example, an extruder, and after cooling, is finely pulverized by a jet mill or the like, and is classified to obtain desired particles. A toner having a diameter can be obtained. Alternatively, a toner having a desired particle size can be obtained by spraying or dispersing the melt-kneaded mixture in an extruder with a spray drier or the like in a liquid state in a molten state.

The toner of the present invention is subjected to the phenomenon of an electrostatic image formed in, for example, an electrophotographic copying machine, and the obtained toner image is fixed by an upper heating roller fixing device electrostatically transferred onto transfer paper to form a copied image. can get. The toner of the present invention is particularly preferably used when fixing is performed at a high speed such that the contact time between the toner on the transfer paper and the heating roller is within 1 second, especially within 0.5 second.

[Examples] Hereinafter, examples of the present invention will be described in detail, but the present invention is not limited to these examples.

<Synthesis of crystalline polyester> (1) Crystalline polyester 1 1500 g (7.41 mol) of sebacic acid and 964 g (8.16 mol) of hexamethylene glycol, a thermometer, a stainless steel stirrer, a glass nitrogen inlet tube and a falling condenser Was placed in a round bottom flask having a capacity of 5, and the flask was placed in a mantle heater, and nitrogen gas was introduced from a glass nitrogen introduction tube to raise the temperature while keeping the inside of the reactor under an inert atmosphere. . Then, 13.2 g of p-toluenesulfonic acid was added and reacted at a temperature of 150 ° C. The reaction was stopped when the amount of water distilled by the esterification reaction reached 250 ml, and the reaction product was taken out. 1.0 kg of this crude crystalline polyester was placed in a beaker of 5 and about 2 kg of xylene was added to make the total volume 4 and stirred well to obtain a uniform solution. This solution was dropped into 20 and methanol using a dropping funnel with stirring for about 1 hour. About 1
After standing for a time, it was filtered and washed twice with about 1 methanol. Then, it was allowed to stand in a warm air at 30 ° C. for a day and night and dried. The acid value of this purified crystalline polyester is 2.8 mgKOH / g,
The hydroxyl value was 10.6 mgKOH / g, Mw = 13,000, Mn = 5,900. This purified product, 1.0 kg and 1.0 g of p-toluenesulfonic acid
Was placed in the round bottom flask described in 5 above, and the temperature was raised to 150 ° C. Then, 13.6 g of acrylic acid was dropped from the dropping funnel, kept at 150 ° C. for about 30 minutes, and after confirming that water was not distilled off by the esterification reaction, the reaction product was taken out. This was cooled to room temperature to obtain a crystalline polyester 1 composed of polyhexamethylene sebacate having an unsaturated double bond at a molecular terminal.

(2) Crystalline polyester 2 1500 g (7.41 mol) of sebacic acid, 506 g (8.16 mol) of ethylene glycol, and 10.0 g of p-toluenesulfonic acid
And purified crystalline polyester was obtained in the same manner as crystalline polyester 1. Acid value is 4.5mgKOH / g, hydroxyl value is 1
3.6 mgKOH / g, Mw = 11,200, Mn = 5,400. 1.0 kg of this purified product was placed in the round bottom flask of the above item 5, and the temperature was raised to 150 ° C. Then, 45.8 g of glycidyl methacrylate was dropped from the dropping funnel and reacted at 150 ° C. for about 30 minutes,
The reaction was removed. This was cooled to room temperature to obtain a crystalline polyester 2 composed of polyethylene sebacate having an unsaturated double bond at a molecular terminal.

(3) Crystalline polyester 3 1000 g (6.85 mol) of adipic acid, 1311 g (7.53 mol) of decamethylene glycol and p-toluenesulfonic acid 1
Using 1.6 g, a purified crystalline polyester was obtained in the same manner as the crystalline polyester 1. The acid value was 4.6 mg KOH / g, the hydroxyl value was 12.6 mg KOH / g, Mw = 13,100, and Mn = 6,560. Next, a crystalline polyester 3 was obtained in the same manner as the crystalline polyester 2 except that 42.0 g of glycidyl methacrylate was used.

<Synthesis of Copolymer> (1) Copolymer A (the present invention) 100 parts by weight of toluene was placed in a separable flask having a capacity of 5, into which 7.5 parts by weight of styrene, 2.5 parts by weight of n-butyl acrylate, and peroxide. After adding 0.02 parts by weight of benzoyl and replacing the gas phase in the flask with nitrogen gas, the temperature was raised to 80 ° C., and the temperature was maintained for 15 hours to perform the first-stage polymerization. Thereafter, the temperature in the flask was cooled to 40 ° C., and 115 parts by weight of the crystalline polyester, 65 parts by weight of styrene, and 10 parts by weight of n-butyl methacrylate were added therein.
After adding 3 parts by weight of benzoyl peroxide and continuing stirring at a temperature of 40 ° C. for 2 hours, the temperature was raised again and kept at that temperature for 8 hours to carry out second-stage polymerization.

Thereafter, toluene was distilled off using an aspirator and a vacuum pump to obtain a graft copolymer A. This graft copolymer A had a weight average molecular weight Mw of 105,000, a ratio Mw / Mn of 18.0, and a softening point Tsp of 110 ° C. This copolymer A had one peak in the molecular weight distribution.

(2) Copolymer B (the present invention) A mixture having the composition shown in Table 1 above was mixed with toluene 10
After adding 0 parts by weight to a separable flask having a capacity of 5 and replacing the gas phase in the flask with nitrogen gas, the temperature was raised to 80 ° C. and kept at this temperature for 15 hours to carry out polymerization. Thereafter, the copolymer B was obtained by distilling off toluene with an aspirator and a vacuum pump. The weight average molecular weight Mw of the copolymer B was 83,000, and the specific Mw
/ Mn was 6.9 and the softening point Tsp was 105 ° C. In addition, this copolymer B had one peak in the molecular weight distribution.

(3) Copolymer C (Invention) In the synthesis of copolymer A, the copolymer was prepared in the same manner except that the charge ratio of the first-stage polymerization and the second-stage polymerization was changed to the composition shown in Table-2. C was obtained.

The weight average molecular weight Mw of this copolymer C was 168,000, and the specific Mw /
Mn was 24.5 and softening point Shimoi Tsp was 115 ° C. The copolymer C had two peaks in the molecular weight distribution.

(4) Copolymer D (the present invention) In the synthesis of copolymer A, the copolymer was prepared in the same manner except that the charge ratio of the first-stage polymerization and the second-stage polymerization was changed to the composition shown in Table-3. D was obtained.

Mw of this copolymer D = 175,000, Mw / Mn = 22.5, Tsp = 1
The temperature was 05 ° C, and there were two peaks in the molecular weight distribution.

(5) Copolymer E (Invention) Copolymer E was obtained in the same manner as copolymer A, based on the charged composition shown in Table-4.

Mw of this copolymer D = 142,000, Mw / Mn = 24.5, Tsp = 1
The temperature was 00 ° C., and there were two peaks in the molecular weight distribution.

(6) Copolymer F (for comparison) 85 parts by weight of styrene 10 parts by weight of n-butyl methacrylate 5 parts by weight of acryloyloxyethyl monosuccinate 4 parts by weight of benzoyl peroxide 100 parts by weight of a monomer mixture having the above composition Was added to a separable flask having a capacity of 1, and the gas phase in the flask was replaced with nitrogen gas.
The temperature was raised to 80 ° C. and kept at this temperature for 15 hours to carry out polymerization.
Thereafter, toluene was distilled off with an aspirator and a vacuum pump to obtain an amorphous vinyl polymer having a carboxyl group. This amorphous vinyl polymer had a weight average molecular weight Mw of 71,000, a ratio Mw / Mn of 7.5, a glass transition point Tg of 67 ° C., and a softening point Tsp of 123 ° C.

85 parts by weight of this amorphous polymer and crystalline polyester 1
In the synthesis of the above, 15 parts by weight of the obtained crude crystalline polyester and 100 parts by weight of xylene were put into a separable flask having a capacity of 5, and nitrogen gas was introduced thereinto while maintaining the inside of the reactor under an inert atmosphere. Let warm. When the amorphous polymer and the crystalline polyester were completely dissolved to form a uniform solution, 0.05 parts by weight of p-toluenesulfonic acid was added, and the mixture was refluxed at 150 ° C. for 1 hour. After xylene was distilled off with an aspirator and a vacuum pump, the reaction product was taken out and cooled to room temperature to obtain a copolymer F. This copolymer F had a weight average molecular weight Mw of 67,000, a value of ratio Mw / Mn of 7.1, and a softening point Tsp of 108 ° C. This copolymer F had one peak in the molecular weight distribution.

(7) Copolymer G (for comparison) In the synthesis of copolymer A, an amorphous polymer having a carboxyl group by changing the charge ratio of the first-stage polymerization and the second-stage polymerization to the composition shown in Table-5 I got

The weight average molecular weight Mw of this amorphous polymer is 165,000, and the specific M
w / Mn: 25,9, glass transition point Tg: 62 ° C, softening point Tsp: 130 ° C
Met. In addition, this amorphous polymer had two peaks in the molecular weight distribution.

85 parts by weight of this amorphous polymer and crystalline polyester 1
15 parts by weight of the crude crystalline polyester obtained in the synthesis of the above, 100 parts by weight of xylene, and p-toluenesulfonic acid
Copolymer G in the same manner as copolymer F using 0.05 parts by weight
I got This copolymer G had a weight average molecular weight Mw of 160,00.
0, the value of the ratio Mw / Mn was 24.3, and the softening point Tsp was 115 ° C.
In addition, this copolymer G had two peaks in the molecular weight distribution.

(8) Copolymer H (for comparison) In the synthesis of copolymer A, an amorphous polymer having a hydroxyl group was obtained by changing the charge ratio of the first-stage polymerization and the second-stage polymerization to the composition shown in Table-6. Was.

The weight average molecular weight of this amorphous polymer is 174,500, specific Mw /
Mn value is 23.7, glass transition point Tg is 63 ° C, softening point Tsp is 12
8.5 ° C. The amorphous polymer had two peaks in its molecular weight distribution.

85 parts by weight of this amorphous polymer and crystalline polyester 2
A copolymer H was obtained in the same manner as the copolymer F using 15 parts by weight of the crude crystalline polyester obtained in the synthesis of the above, 100 parts by weight of xylene, and 2 parts by weight of hexamethylene diisocyanate. This copolymer H has a weight average molecular weight Mw of 17
The value of Mw / Mn was 1,000 and the softening point Tsp was 118 ° C. The copolymer H had two peaks in the molecular weight distribution.

(9) Copolymer I (for comparison) In a separable flask having a capacity of 5 was charged 100 parts by weight of toluene, into which 15 parts by weight of the crystalline polyester 1, 65 parts by weight of styrene, and 20 parts by weight of n-butyl acrylate. And 0.2 parts by weight of benzoyl peroxide, and the gas phase in the flask was replaced with nitrogen gas. Thereafter, the temperature was raised to 80 ° C., and the temperature was maintained for 15 hours to carry out polymerization. Thereafter, the toluene was distilled off with an aspirator and a vacuum pump to obtain a copolymer I. The copolymer I had a weight average molecular weight Mw = 4
9,000, the value of the ratio Mw / Mn was 3.2, and the softening point Tsp was 135 ° C. In addition, this copolymer I had one peak in the molecular weight distribution.

(10) Copolymer J (for comparison) A xylene solution of a fluorine-containing copolymer having a hydroxyl group (Lumiflon LF210, hydroxyl value 108, number average molecular weight Mn = 2
5,000, solid content 50%, 100 parts by weight (manufactured by Asahi Glass Co., Ltd.) were placed in a 5-separable flask, the gas phase in the flask was replaced with nitrogen gas, and the temperature was raised to 50 ° C. Then, a mixed solution of maleic anhydride (0.6 part by weight) and xylene (0.6 part by weight) was dropped from a dropping funnel and reacted at 50 ° C. for 1 hour and then at 1290 ° C. for 2 hours. After a part of the reaction product was taken out and the unsaturated double bond was brominated, it was confirmed by titration that the copolymer was a fluorine-containing copolymer having 0.013 mol of double bonds per 100 g of the copolymer. The copolymer solution was further added with 50 parts of xylene and heated to 100 ° C. After replacing the gas phase in the flask with nitrogen gas, a mixed solution of 30 parts by weight of styrene, 20 parts by weight of n-butyl methacrylate, and 1.5 parts by weight of azobisisobutyronitrile was dropped from the dropping funnel over 2 hours. The reaction was carried out at the same temperature for 4 hours. Thereafter, xylene was distilled off with an aspirator and a vacuum pump to remove the reaction product, which was cooled to room temperature to obtain a copolymer J. Copolymer J had a weight average molecular weight Mw of 43,000 and a specific Mw / Mn.
Was 3.75 and the softening point was 135 ° C. The copolymer J had one peak in the molecular weight distribution.

Examples 1 to 5 Each of the copolymers A to E was placed in a V-type mixer at a ratio shown in Table 7 above, mixed for 20 minutes, and melt-kneaded by a twin-screw extruder. After cooling, the mixture was coarsely pulverized by a wheely mill to obtain a 2-mm mesh pass product. The powder was further pulverized by a supersonic jet mill, and then fine powder having a particle diameter of 5 μm or less was removed by an air classifier to obtain colored fine particles having an average particle diameter of 11 μm.

0.8 parts by weight of silica and 0.05 parts by weight of zinc stearate were mixed with 100 parts by weight of the colored fine particles by a V-type mixer to obtain five kinds of toners of the present invention. These are referred to as toners 1 to 5.

Comparative Examples 1 to 4 and 6 Comparative toners 1 to 4 and 6 were obtained in the same manner as in Examples 1 to 5, except that the copolymers F to I and J were used.

Comparative Example 5 Comparative toner 5 was obtained in the same manner as in Example except that a mixture of 15 parts by weight of crystalline polyester 1 and 85 parts by weight of the amorphous polymer obtained in the synthesis of copolymer G was used.

The following evaluations were performed for the above toners 1 to 5 and comparative toners 1 to 6, and the results are shown in Table-8.

<Evaluation> (1) Measurement of graft ratio Graft was measured using ¹ H-NMR. For copolymers A to E and copolymer I, the ratio between the signal intensity of the unsaturated double bond of the crystalline polyester and the signal intensity of the main chain methylene group was measured and calculated from the degree of decrease before and after the graft reaction.

For the copolymers F to H, the ratio of the signal intensity of the main chain methylene group to the signal intensity of the terminal methylene group of the crystalline polyester was measured and calculated from the degree of decrease before and after the graft reaction.

For the copolymer J, the unsaturated double bond was brominated, quantified by titration, and calculated from the reduction ratio before and after the graft reaction.

(2) Crushability The supersonic jet mill "PJM-1"
00 "(manufactured by Nippon Pneumatic Industries, Ltd.), the amount of supply required to obtain an average particle size of 10 μm at the time of pulverization was measured and used as an index of pulverizability. Discharge air pressure 6.0Kg / cm
^{In 2} , the supplied amount of 15 g / min or more was rated as “○”, 5 to 15 g / min was rated as “△”, and less than 5 g / min was rated as “×”.

(3) Evaluation of fluidity Taking advantage of the fact that the higher the fluidity of powder, the smaller the degree of compression, the above toner is loosely filled into a container having a diameter of 28 mm and a capacity of 100 ml from above and the weight is measured. The static bulk density was determined. Evaluation is `` ○ '' when the static bulk density is 0.40 g / ml or more,
Less than 0.40 g / ml was marked as “x”.

(4) Evaluation of aggregability Take 2 g of each toner in a sample tube and tap 500 times with a tap densor, leave it for 2 hours in an atmosphere of a temperature of 60 ° C. and a relative humidity of 34%, and then separate with a 48 mesh comb. The proportion of the aggregate remaining on the comb was measured.

(5) Evaluation of low-temperature fixability Each toner is mixed with a coated carrier in which a fluorinated alkyl methacrylate polymer having a repeating unit represented by the following formula is coated on a ferrite core material having an average particle diameter of 80 μm so as to be 2% by weight. And its content (toner density) is 5
A two percent by weight two-component developer was prepared.

An electrophotographic copier "U-Bix1550MR" that is equipped with a latent image carrier made of an organic photoconductive semiconductor, a developing device for two-component developer, and a heating roller fixing device, and has been modified so that the set temperature of the heating roller can be variably adjusted. (Konica Corporation) The remodeling machine set the linear speed of the heating roller to 139 mm / sec, and kept the temperature of the pressure roller at a lower temperature than the setting temperature of the heating roller, and set the temperature of the heating roller to 100 to 240. While stepwise changing the temperature in the range of ° C., a real image test was performed to form a fixed toner image using each of the above-mentioned developers, and a constant load was applied to the end of the obtained fixed toner image using a rubbing tester. After rubbing, the residual rate of the image at the end was measured with a microdensitometer, and the lowest set temperature (minimum fixing temperature) showing a residual rate of 80% or more was determined. The heating roller fixing device has a surface layer of PFA (tetrafluoroethylene-perfluoroalkylvinylether copolymer) having a diameter of 30 mm.
mm, and a pressure roller made of silicone rubber “KE-1300RTV” (manufactured by Shin-Etsu Chemical Co., Ltd.) whose surface layer is covered with PFA, with a linear pressure of 0.8 kg / cm and a nip width of 4.3 mm. mm and does not have a release agent application mechanism such as silicone oil.

(6) Evaluation of hot offset resistance A fixed toner image was formed in the same manner as in the evaluation of the low-temperature fixing property except that the pressure roller was kept at a temperature close to the set temperature of the heating roller. An operation of feeding the recording material to the heat roller fixing device under the same conditions and visually observing whether or not toner stains occur is performed at each set temperature of the heat roller, and the operation when the toner stain occurs is the lowest. The set temperature (offset occurrence temperature) was determined.

(7) High temperature and high humidity environment conditions (temperature 33 ° C, relative humidity 80%)
Electrophotographic copier "U-Bix1550M" equipped with the above-described organic latent image carrier, a developing device for a two-component developer, and a heating roller fixing device.
R "(manufactured by Konica Corporation), the upper roller temperature was set to the minimum fixing temperature, and the above developer was used under high-temperature and high-humidity environmental conditions (temperature 33 ° C, relative humidity 80%). A real-image test for forming a copy image was performed using each of them, and the image quality of the obtained image was visually evaluated.

From the results in Table 8, according to the production method of the present invention, a copolymer having a high graft ratio can be obtained. Also, from the results in Table 8, the toner of the present invention containing the copolymer according to the present invention as a binder has good low-temperature fixability and offset resistance, and is excellent in pulverizability, fluidity, and aggregation resistance, Further, it can be seen that good image quality can be obtained even under high temperature and high humidity conditions.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-164755 (JP, A) JP-A-59-15944 (JP, A) JP-A-63-27855 (JP, A) JP-A 64-64 35455 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) G03G 9/087

Claims (2)

(57) [Claims] 1. A vinyl monomer is polymerized in the presence of a crystalline polyester having an unsaturated double bond at a molecular terminal, and the ratio Mw / Mn of the number average molecular weight Mn to the weight average molecular weight Mw is 3.5 or more. A method for producing a binder resin for a toner, characterized in that a block copolymer or a graft copolymer is obtained. 2. A value of a ratio Mw / Mn of a number average molecular weight Mn to a weight average molecular weight Mw obtained by polymerizing a vinyl monomer in the presence of a crystalline polyester having an unsaturated double bond at a molecular terminal. Characterized in that the toner comprises a block copolymer or a graft copolymer having a particle size of 3.5 or more as a binder resin.