JP2872347B2 - Binder resin for toner, method for producing the same, and toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a binder resin for toner applied to an electrophotographic method, an electrostatic printing method, an electrostatic recording method and the like, a method for producing the same, and a binder resin for the toner The present invention relates to a toner using

[Conventional technology]

For example, in electrophotography, usually, an electrostatic latent image is formed by charging and exposing an electrostatic image carrier made of a photoconductive photoreceptor, and then applying the colorant and the like to a binder resin. The resulting toner image is developed with toner that is contained and formed into fine particles, 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.

In recent years, however, the miniaturization and speeding up of copying machines have been progressing, suppressing overheating deterioration of the copying machine, preventing heat deterioration of the photoconductor, and setting a temperature at which the heat roller can be fixed after the fixing device is operated. To reduce the warm-up time required to ascend the transfer roller, reduce the temperature drop of the heat roller due to the heat absorbed by the transfer paper, and enable multiple continuous copying, thermal safety Therefore, it is strongly demanded to reduce the power consumption of the fixing heater so that the fixing process can be performed with the temperature of the heat roller lowered. Therefore, it is necessary that the toner can be well fixed at a low temperature.

Moreover, 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 transferred to the surface of the heat roller at the time of fixing, and this is likely to be transferred again to the next transfer paper to stain the image. It is necessary to provide performance for preventing the occurrence of the offset phenomenon, that is, imparting offset resistance.

For these reasons, the following technologies have been proposed in the past.

(1) In JP-A-63-27855, the ratio of the crystalline polyester to the ratio Mw of the weight average molecular weight Mw to the number average molecular weight Mn is described.
There is disclosed a toner using, as a binder resin, a block copolymer or a graft copolymer with an amorphous vinyl polymer having a value of / Mn of 3.5 or more.

(2) In JP-A-63-27856, a block copolymer or a graft copolymer of a crystalline polyester and an amorphous vinyl polymer having two or more peaks in molecular weight distribution is used as a binder resin. A toner is disclosed.

(3) JP-A-64-35456 discloses a method for producing a toner in which a block copolymer or a graft copolymer of a crystalline polyester and an amorphous vinyl polymer is used as a binder resin and a heat treatment step is added. Is disclosed.

[Problems to be solved by the invention]

However, all of the above techniques (1) to (3) utilize a reaction by p-toluenesulfonic acid (ester bond), hexamethylene diisocyanate (urethane bond) or heat (bond by amide bond or epoxy group). Thus, the crystalline polyester and the amorphous (amorphous) vinyl polymer are chemically bonded.

However, in the reaction with p-toluenesulfonic acid and heat, the block ratio or graft ratio, which is the bonding ratio between the crystalline polyester and the amorphous vinyl polymer, was low, and the low-temperature fixability was insufficient. This is because unreacted crystalline polyesters aggregate with each other to form large domains,
It is considered that even if a local decrease in the viscosity occurs during heating, the viscosity of the entire toner particles does not decrease.
Further, since large domains of the crystalline polyester component are formed in the toner particles, the fluidity of the toner particles is low.

On the other hand, in the reaction with isocyanate,
Since the coupling bond between groups occurs and the reaction proceeds randomly, the block ratio or the graft ratio also decreases. In addition, when a reaction occurs between the crystalline polyesters, there is a disadvantage that macromolecules are formed and pulverizability is reduced.

The present invention has been made based on the above circumstances, and a first object of the present invention is to improve the low-temperature fixability and the offset resistance of a toner and to improve the pulverizability at the time of manufacturing a toner. To provide a binder resin for a toner that can be used.

A second object of the present invention is to provide a method for producing a binder resin for a toner, which can increase the block ratio or the graft ratio in a copolymer.

A third object of the present invention is to provide a toner having good low-temperature fixability, offset resistance, fluidity and blocking resistance.

A fourth object of the present invention is to provide a toner which has low environmental dependence and can obtain good image quality even under high temperature and high humidity conditions.

[Means for solving the problem]

In order to achieve the above object, the present inventors, when using a block copolymer or a graft copolymer of a crystalline polyester and an amorphous vinyl polymer as a binder resin for toner, the block ratio in the copolymer Focusing on the fact that the graft ratio is a factor that greatly affects properties such as low-temperature fixability, offset resistance, and blocking resistance of the toner, and satisfying the block ratio or the graft ratio in any range, the above-described excellent toner is obtained. After intensive studies on whether or not the toner can impart such characteristics, it was found that if the block ratio or the graft ratio is in the range of 40 to 90%, it is possible to impart sufficiently satisfactory characteristics to the toner. Bonding of Crystalline Polyester and Amorphous Vinyl Polymer Using Condensing Agent Composed of Agent and Oxidizing Agent As a result, they have found that the block ratio or the graft ratio can be efficiently controlled in the range of 40 to 90%, and have completed the present invention.

Therefore, the binder resin for a toner of the present invention has a crystalline polyester, a functional group capable of forming a bond with the crystalline polyester, and a weight average molecular weight Mw and a number average molecular weight.
A block ratio indicating a bonding ratio in the copolymer, comprising a block copolymer or a graft copolymer in which an amorphous vinyl polymer having a ratio of Mn / Mn / Mn of 3.5 or more is chemically bonded. Alternatively, the graft ratio is 40 to 90%.

Further, the binder resin for a toner of the present invention has a crystalline polyester, a functional group capable of forming a bond with the crystalline polyester, and a weight average molecular weight Mw and a number average molecular weight.
An amorphous vinyl polymer having a ratio of Mn Mw / Mn of 3.5 or more is composed of a block copolymer or a graft copolymer chemically bonded by a condensing agent consisting of a reducing agent and an oxidizing agent. It is characterized by the following.

In the method for producing a binder resin for a toner according to the present invention, the crystalline polyester has a functional group capable of forming a bond with the crystalline polyester and has a weight average molecular weight.
An amorphous vinyl polymer having a ratio Mw / Mn of Mw to the number average molecular weight Mn of 3.5 or more is chemically bonded with a condensing agent comprising a reducing agent and an oxidizing agent to form a block copolymer or a graft copolymer. It is characterized by forming a polymer.

Further, the toner of the present invention is characterized by containing the binder resin for a toner described above.

That is, in the present invention, by using a specific copolymer having a block ratio or a graft ratio in the range of 40 to 90% as a binder resin, the crystalline polyester component provides excellent low-temperature fixability to the toner and good meltability. The amorphous vinyl polymer component imparts excellent low-temperature fixability, offset resistance, blocking resistance, and fluidity to the toner.

Then, when synthesizing a block copolymer or a graft copolymer of a crystalline polyester and an amorphous vinyl polymer, by adopting a special configuration of using a condensing agent consisting of a reducing agent and an oxidizing agent, This enables synthesis of a copolymer having a block ratio or a graft ratio in the range of 40 to 90%.

 Hereinafter, the configuration of the present invention will be specifically described.

The binder resin for a toner of the present invention basically comprises a block copolymer or a graft copolymer in which a crystalline polyester and an amorphous vinyl polymer are chemically bonded.

It is necessary that the amorphous vinyl polymer has a functional group capable of forming a bond with the crystalline polyester used in combination, and that the ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn is 3.5 or more.

As the functional group, a carboxyl group, a hydroxyl group, an amino group and the like are preferable. Examples of the monomer having the functional group that can be used to obtain the amorphous vinyl polymer having the functional group include acrylic acid, β, β-dimethylacrylic acid, α-ethylacrylic acid, and methacrylic acid. , Fumaric acid, itaconic acid, maleic acid, crotonic acid,
Hydroxyethyl methacrylate, acryloyloxyethyl monophthalate, acryloyloxyethyl monosuccinate, N-hydroxyethyl acrylamide,
N-hydroxyethyl methacrylamide, N-methylolacrylamide, p-aminostyrene, and the like can be mentioned. A monomer having such a functional group is
In the monomer composition for obtaining the amorphous vinyl polymer, 0.1.
It is used at a ratio in the range of 1 to 20 mol%, preferably 0.5 to 10 mol%.

An amorphous vinyl polymer is synthesized from a polymerization composition containing a monomer having a functional group as described above. However, a vinyl polymer constituting a main part of the amorphous vinyl polymer is particularly limited. Not something. Examples of the vinyl polymer as the main component include polystyrene, polymethyl methacrylate, polymethyl acrylate, polyvinyl chloride, polyvinyl acetate, polyacrylonitrile, and the like. Of these, styrene-based polymers, acrylic-based polymers, and styrene-acryl-based polymers are particularly preferred. Examples of a monomer for obtaining such a polymer include 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, t-butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate, cyclohexyl methacrylate, dimethylaminoethyl methacrylate, and others. Can be. These monomers can be used alone or in combination of several kinds.

In the amorphous vinyl copolymer used in the present invention, the value of the ratio Mw / Mn needs to be 3.5 or more, as described above, and particularly preferably in the range of 7 to 30. The value of this ratio Mw / Mn is
If it is less than 3.5, it is difficult to impart sufficient offset resistance and durability to the toner.

The values of Mw and Mn of the amorphous vinyl polymer can be determined by various methods, and there are some differences depending on the difference in the measuring method. In the present invention, the values are defined as the values determined by the following measuring methods. That is, Mw, Mn, and peak molecular weight are measured by gel permeation chromatography (GPC) under the following conditions.

At a temperature of 40 ° C., a solvent (tetrahydrofuran) is flowed at a flow rate of 1.2 ml / min, and 3 mg of a tetrahydrofuran sample solution having a concentration of 0.2 g / 20 ml is injected as a sample weight for measurement.
When measuring the molecular weight of the sample, a measurement condition is selected in which the logarithm of the molecular weight and the count number of the calibration curve prepared from several types of monodisperse polystyrene standard samples are included in a straight line.

Note that the reliability of the measurement results was determined using the NBS706 polystyrene standard sample (Mw = 28.8 × 10 ⁴ , Mn = 1) measured under the above measurement conditions.
Confirm that the value of the ratio Mw / Mn of 3.7 × 10 ⁴ , Mw / Mn = 2.11) is 2.11 ± 0.10.

The GPC column to be used is not particularly limited as long as it satisfies the above conditions. For example, TSK-GE
L, GMH (manufactured by Toyo Soda Co., Ltd.) or the like can be used. Further, the solvent and the measurement temperature are not limited to the above conditions, and may be changed to other conditions as appropriate.

The amorphous vinyl polymer used in the present invention preferably has at least two or more maximum values in the molecular weight distribution. By using such an amorphous vinyl polymer, the low-temperature fixability and offset resistance of the toner can be further improved. Specifically, the amorphous vinyl polymer has a molecular weight distribution divided into at least two groups of a low molecular weight component and a high molecular weight component, and at least one local maximum value is 2 in a molecular weight distribution curve measured by GPC. It is preferred to have at least two maxima, such as in the range of × 10 ^{3 to} 2 × 10 ⁴ , with at least one maxima in the range of 1 × 10 ⁵ to 1 × 10 ⁶ .

Further, the amorphous vinyl polymer used in the present invention preferably has a glass transition point Tg of 50 to 100 ° C, particularly preferably 50 to 85 ° C. When the Tg is less than 50 ° C., it becomes difficult to impart sufficient blocking resistance to the toner. On the other hand, when the Tg exceeds 100 ° C., the toner has sufficient low-temperature fixability because the melt fluidity at low temperatures is reduced. It becomes difficult. The Tg of the amorphous vinyl polymer means a glass transition point of the amorphous vinyl polymer in a state where the amorphous vinyl polymer is not bonded to the crystalline polyester. Further, the glass transition point Tg can be measured by, for example, “DSC-20” (manufactured by Seiko Instruments Inc.) in accordance with the differential scanning calorimetry (DSC). Heating was performed at a temperature rate (10 ° C./min), and the glass transition point was determined from the intersection of the baseline and the slope of the endothermic peak.

The crystalline polyester used in the present invention is not particularly limited, but a polyalkylene polyester is particularly preferred from the viewpoint of imparting sufficient low-temperature fixability and fluidity to the toner.

Specific examples of such a polyalkylene polyester include polyethylene sebacate, polyethylene adipate, polyethylene suberate, polyethylene succinate, polyethylene-p- (carbophenoxy) undecaate, polyhexamethylene oxalate, polyhexamethylene sebacate, and polyhexamethylene sebacate. Hexamethylene decanedioate, polyoctamethylene dodecanedioate, polynonamethylene azelate, polydecamethylene adipate,
Polydecamethylene azelate, polydecamethylene oxalate, polydecamethylene sebacate, polydecamethylene succinate, polydecamethylene octadecanedioate, polytetramethylene sebacate, polytrimethylene dodecandioate, polytrimethylene octadecandio Ethates, polytrimethylene oxalate, polyhexamethylene-decamethylene-sebacate, polyoxydecamethylene-2-methyl-1,3-propane-dodecandioate, and the like can be mentioned.

The crystalline polyester used in the present invention has a melting point Tm.
It is preferably in the range of 50 to 120 ° C, especially 50 to 100 ° C. When the Tm is less than 50 ° C., it is difficult to impart sufficient blocking resistance to the toner. On the other hand, when the Tm exceeds 120 ° C., the toner has sufficient low-temperature fixability because the melt fluidity at low temperatures is reduced. It becomes difficult. In addition, Tm of the crystalline polyester means the melting point of the crystalline polyester in a state where it is not bonded to the amorphous vinyl polymer. In addition, the melting point Tm can be measured by, for example, “DSC-20” (manufactured by Seiko Instruments Inc.) in accordance with the differential scanning calorimetry (DSC). The melting peak value when heated at (10 ° C./min) is defined as the melting point Tm.

The crystalline polyester used in the present invention has a Mw of 5,000 to 5
It is preferable that Mn is in the range of 2,000 to 20,000. When the molecular weight is in this range, more excellent offset resistance can be imparted to the toner, and the pulverizability during the production of the toner can be further increased.

In the present invention, a block copolymer or a graft copolymer obtained by chemically bonding the above crystalline polyester and an amorphous vinyl polymer is used as a binder resin for a toner. The proportion of the polyester component is preferably in the range of 3 to 50% by weight, particularly preferably 5 to 40% by weight. 3% by weight of crystalline polyester component
When it is less than 50%, it is difficult to impart sufficient low-temperature fixability to the toner. On the other hand, when it exceeds 50% by weight, the melt elastic modulus at the time of fixing becomes small, so that it is difficult to impart sufficient offset resistance to the toner. Becomes

The crystalline polyester and the amorphous vinyl polymer used in combination to obtain the binder resin for a toner of the present invention are:
They may be compatible or incompatible with each other, but are preferably incompatible from the viewpoint of improving the blocking resistance of the toner and the pulverizability during the production of the toner. Here, "incompatible" means that the chemical structures of the two are the same or similar or that there is no property that both are sufficiently dispersed by the action of a functional group, and the solubility parameter such as SP value by the method of Fedose ( RFFedor
s, Polym.Eng.Sci., 14 , (2) 147 (1974))
It is bigger.

In the block copolymer or the graft copolymer constituting the binder resin for a toner of the present invention, the block ratio or the graft ratio indicating the bonding ratio between the crystalline polyester and the amorphous vinyl polymer is in the range of 40 to 90%. It is necessary to be. If the block ratio or the graft ratio is in this range, sufficient low-temperature fixability, offset resistance, fluidity, and blocking resistance can be imparted to the toner.
Further, the pulverizability during the production of the toner can be remarkably improved.

In the present invention, the block ratio or the graft ratio is the ratio of the crystalline polyester actually bonded to the amorphous vinyl polymer among the added crystalline polyesters, and before and after the block copolymerization reaction or the graft copolymerization reaction. It is calculated from the change in the number of functional groups at the terminal of the crystalline polyester molecule. Specifically, ¹ H-NMR (for example, FT-N
MR, GX-400 (manufactured by JEOL Ltd.)) as follows.

That is, for example, in the following crystalline polyalkylene polyester [I] having a hydroxyl group at a molecular terminal, a signal of a proton (b) of a methylene group bonded to an oxygen atom is obtained.
The signal of the proton (a) of the methylene group bonded to the hydroxyl group at the molecular terminal is 4.0 to 4.1 ppm.
From these strength ratios, the ratio of the number of hydroxyl groups (a) at the molecular end of the crystalline polyester to the number of methylene groups (b) bonded with oxygen atoms can be determined. Similarly, the ratio of the number of hydroxyl groups at the molecular terminals of the crystalline polyester in the block copolymer or the graft copolymer to the number of methylene groups bonded to oxygen atoms was determined, and the number of hydroxyl groups at the molecular terminals before and after the reaction was calculated using the formula (II). The block rate or the graft rate is calculated from the change in

In the binder resin for a toner of the present invention, a crystalline polyester and the specific amorphous vinyl polymer are chemically combined with a condensing agent comprising a reducing agent and an oxidizing agent to form a block copolymer or It preferably comprises a graft copolymer.

Examples of the condensing agent comprising such a reducing agent and an oxidizing agent include, for example, triphenylphosphine-disulfide, triphenylphosphine-polyhalide, triphenylphosphine-carbon tetrachloride-imidazole, picryl chloride-pyridine, Phosphoric triester-thionyl chloride type and the like can be mentioned.

The condensing agent composed of such a reducing agent and an oxidizing agent is preferably used in an amount equivalent to the functional groups present in the crystalline polyester and the amorphous vinyl polymer used. When the amount of the condensing agent used is too small for the functional group, it is difficult to increase the block ratio or the graft ratio.

Such a block copolymer or a graft copolymer is prepared, for example, by dissolving a crystalline polyester and an amorphous vinyl polymer in a solvent to prepare a uniform solution, and then forming a condensation solution comprising a reducing agent and an oxidizing agent. The solution can be produced by gradually dropping a solution in which the agent is dissolved to allow the reaction to proceed.

Also, to increase the block rate or graft rate,
It is preferable that one of the crystalline polyester and the amorphous vinyl polymer has a carboxyl group as a functional group and the other has a hydroxyl group and / or an amino group as a functional group.

As described above, the binder resin for a toner of the present invention is composed of a specific copolymer and has a block ratio or a graft ratio in the range of 40 to 90%. In addition to imparting good wettability and good wettability upon melting, the amorphous vinyl polymer component can impart excellent low-temperature fixability, offset resistance, blocking resistance, and fluidity to the toner.

On the other hand, when the block ratio or the graft ratio is less than 40%, sufficient low-temperature fixability cannot be imparted to the toner, and the domain of the crystalline polyester component in the toner particles becomes large. Reduces the fluidity of On the other hand, when the block ratio or the graft ratio exceeds 90%, the crystalline polyester component in the copolymer becomes compatible with the amorphous vinyl polymer component and lowers the glass transition temperature of the copolymer. It is difficult to impart sufficient blocking resistance to the film.

Next, the toner of the present invention will be described. The toner of the present invention uses the specific copolymer described above as a binder resin, a coloring agent, a magnetic material used as needed,
It is configured to contain a toner component such as a property improving agent. In the toner of the present invention, other resins may be used as the binder resin in addition to the above specific copolymer. However, the content ratio of the above specific copolymer in the whole binder resin is preferably 30% by weight or more, and particularly preferably in the range of 50 to 100% by weight.

Examples of the coloring agent used in the toner include carbon black, nigrosine dye (CINo. 50415B), aniline blue (CINo. 50405), and calco oil blue (CI
No.azoic Blue3), Chrome Yellow (CINo.14090),
Ultramarine Blue (CINo.77103), Dupont Oil Red (CINo.26105), Quinoline Yellow (CIN
o.47005), methylene blue chloride (CINo.5201)
5), phthalocyanine blue (CINo. 74160), malachite green oxalate (CINo. 42000), rose bengal (CINo. 45435), and mixtures thereof. The amount of the colorant to be used is generally in the range of 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the toner.

The magnetic material used in the toner includes ferrite, magnetite and other ferromagnetic metals or alloys, such as iron, cobalt, and nickel, or compounds containing these elements or ferromagnetic elements. Alloys that become ferromagnetic when applied, such as manganese-copper-aluminum, manganese-copper-tin, and other alloys of the type called Heusler alloys containing manganese and copper, or chromium dioxide, etc. . For example, in the case of obtaining a black toner, magnetite, which is itself black and also functions as a colorant, is preferable. When a color toner is to be obtained, a toner having less blackness such as metallic iron is preferable. 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 are contained in the form of fine powder having an average particle size of 0.1 to 1 μm. In magnetic toners, the content is
It is preferably from 20 to 70% by weight, particularly preferably from 40 to 70% by weight.

Examples of the property improving agent used in the toner include a fixing property improving agent and a charge control agent.

Examples of the fixability improver include polyolefin wax, 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, and the like. In particular, the softening point (ring and ball method JIS K 2531) is 60
Waxes of ~ 150 ° C are preferred.

As the charge control agent, a conventionally known charge control agent can be used. For example, a nigrosine dye, a metal-containing dye and the like can be mentioned.

In one example of the method for producing a toner of the present invention, a binder resin containing at least the above specific copolymer and a toner component such as a colorant are mixed, and the mixture is melt-kneaded by, for example, an extruder or the like. Finely pulverized with a mill or the like, and classified to produce a toner having a desired particle size.

Further, in another example of the method for producing a toner of the present invention, a desired particle is obtained by spraying or dispersing the melt-kneaded mixture in a liquid state with a spray dryer or the like in the same manner as described above. A toner having a diameter is manufactured.

Further, in the present invention, the toner obtained as described above may be mixed with inorganic fine particles such as a fluidity improver to form a toner.

As such inorganic fine particles, the primary particle diameter is 5 nm to 2 μm.
m, especially those in the range of 5 nm to 500 nm are preferred. The BET specific surface area of the inorganic fine particles is preferably in the range of 20 to 500 m ² / g.

The addition ratio of the inorganic fine particles is preferably in the range of 0.01 to 5% by weight, particularly 0.01 to 2.0% by weight of the whole toner.

As constituent materials of the inorganic fine particles, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, oxide Examples include chromium, cerium oxide, red iron oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride, and the like. Of these, silica fine powder is particularly preferred.

The silica fine powder referred to here is a fine powder having a Si-O-Si bond, and may be any one produced by a dry method or a wet method. In addition to anhydrous silicon dioxide,
Any of aluminum silicate, sodium silicate, potassium silicate, magnesium silicate, zinc silicate and the like may be used, but one containing 85% by weight or more of SiO ₂ is preferable.

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 R-972, R-974, R-805, R-81
2 (above, manufactured by Aerosil Co., Ltd.) and Tarax 500 (manufactured by Tarco Co., Ltd.). In addition, fine powder of silica 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 also be used.

The toner of the present invention is used for developing an electrostatic latent image formed in, for example, an electrophotographic copying machine, and the obtained toner image is electrostatically transferred onto transfer paper and then fixed by a heating roller fixing device to be copied. An image is obtained. 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, for example, within 1 second, especially within 0.5 second.

〔Example〕

Hereinafter, examples of the present invention will be described in a comparative manner, but the present invention is not limited to these embodiments.
In the following, “parts” means “parts by weight”.

<Crystalline Polyester 1> 1500 g (7.41 mol) of sebacic acid and 964 g (8.16 mol) of hexamethylene glycol were charged in a volume of 5 l equipped with a thermometer, a stainless steel stirrer, a glass nitrogen gas inlet tube and a sinking condenser. Was placed in a mantle heater, and nitrogen gas was introduced from a glass nitrogen introducing tube to raise the temperature while keeping the inside of the reactor under an inert atmosphere. And 13.2g of p-
Toluenesulfonic acid was added and reacted at a temperature of 150 ° C.
The reaction was stopped when the amount of water that had flowed out of the esterification reaction reached 250 ml, and the reaction product was taken out. This was cooled to room temperature to obtain a crystalline polyester 1 comprising polyhexamethylene sebacate having a hydroxyl group at a molecular terminal. The melting point Tm of this crystalline polyester 1 was 64 ° C. However, melting point Tm is a differential scanning calorimeter "DSC-20"
(Manufactured by Seiko Instruments Inc.). The weight average molecular weight Mw of the crystalline polyester 1 is 12,300.
Met.

<Crystalline polyester 2> Tm =
A crystalline polyester 2 made of polyethylene sebacate having an Mw of 11,000 at 70 ° C. was obtained.

<Crystalline polyester 3> Tm =
A crystalline polyester 3 consisting of polydecamethylene adipate having an Mw of 13,100 at 74 ° C. was obtained.

<Amorphous vinyl polymer 1> To a separable flask having a capacity of 1 was charged 100 parts of toluene, into which 7.5 parts of styrene and 2.5 parts of butyl acrylate were added.
And 0.1 part of benzoyl peroxide, and the gas phase in the flask was replaced with nitrogen gas. Then, the temperature was raised to 80 ° C., and the temperature was maintained at that temperature for 15 hours to perform the first-stage polymerization.

Thereafter, the flask was cooled to a temperature of 40 ° C., and 85 parts of styrene, 10 parts of butyl methacrylate, 5 parts of acrylic acid, and 4 parts of benzoyl peroxide were added thereto, and the mixture was heated at 40 ° C. for 2 hours. After the stirring was continued, the temperature was raised again to 80 ° C., and the temperature was kept at that temperature for 8 hours to perform the second-stage polymerization.

Next, zinc oxide, which is a polyvalent metal compound, is placed in the flask.
0.5 g was added, and the reaction was carried out for 2 hours while stirring at a reflux temperature.

Thereafter, toluene was distilled off using an aspirator and a vacuum pump, followed by drying to produce an amorphous vinyl polymer 1 in which zinc oxide reacted with a carboxyl group of the vinyl polymer to form an ionic cross-linking bond. The amorphous vinyl polymer 1 has a carboxyl group as a functional group for bonding to the crystalline polyester.

This amorphous vinyl polymer 1 has two peaks in the molecular weight distribution by GPC, the peak molecular weight on the high molecular weight side is 251,200, and the peak molecular weight on the low molecular weight side is 4,000. The weight average molecular weight Mw was 93,200, and the value of the ratio Mw / Mn was 1
8.4, glass transition point Tg is 60 ° C, softening point Tsp is 128 ° C.

<Amorphous vinyl polymer 2> 85 parts of styrene 10 parts of n-butyl methacrylate 5 parts of acryloyloxyethyl monosuccinate 5 parts 4 parts of benzoyl peroxide The monomer mixture having the above composition is separable in a capacity of 1 containing 100 parts of toluene. After the gas phase in the flask was replaced with nitrogen gas, the temperature was increased to 80 ° C.
The polymerization was carried out while maintaining the temperature at this temperature for 15 hours. Thereafter, toluene was distilled off with an aspirator and a vacuum pump to obtain an amorphous vinyl polymer 2 which is a styrene-acrylic resin having a carboxyl group. This amorphous vinyl polymer 2 has one peak in the molecular weight distribution by GPC, and the peak molecular weight is 65,000.
Met. Also, Mw is 71,000, the value of ratio Mw / Mn is 7.5, and Tg is
67 ° C, Tsp was 123 ° C.

<Amorphous vinyl polymer 3> Same as in the production of amorphous vinyl polymer 1, except that the monomers used in the first stage polymerization were changed to 15 parts of styrene, 5 parts of butyl acrylate, and 0.04 part of benzoyl peroxide. Thus, an amorphous vinyl polymer 3 was obtained.

This amorphous vinyl polymer 3 has two peaks in the molecular weight distribution by GPC, the peak molecular weight on the high molecular weight side is 363,000, and the peak molecular weight on the low molecular weight side is 7,590. Further, Mw is 165,000, the value of the ratio Mw / Mn is 25.9, and Tg is 62.
° C and Tsp are 130 ° C.

<Amorphous vinyl polymer 4> An amorphous vinyl polymer 4 was obtained in the same manner as the amorphous vinyl polymer 3, except that 5 parts of acrylic acid, which was a monomer of the second stage polymerization, was changed to 5 parts of hydroxyethyl methacrylate. Was. The amorphous vinyl polymer 4 has a hydroxyl group as a functional group for bonding to the crystalline polyester, and has a peak of 2 in the molecular weight distribution by GPC.
The peak molecular weight on the high molecular weight side is 395,000, and the peak molecular weight on the low molecular weight side is 9,430. Mw is 174,5
00, the value of the ratio Mw / Mn is 23.7, Tg is 63 ° C, and Tsp is 128.5 ° C.

<Copolymer A> Crystalline polyester 1 225 g (15 parts) Amorphous vinyl polymer 1 1275 g (85 parts) The above materials were placed in a 5-liter separable flask containing 1.5 l of xylene, and nitrogen gas was introduced. Then, the temperature was raised while maintaining the inside of the reactor in an inert atmosphere. When crystalline polyester and amorphous vinyl polymer are completely dissolved in xylene to form a homogeneous solution, a condensing agent consisting of 10.2 g of triphenylphosphine as a reducing agent and 8.5 g of 2,2'-dipyridyldisulfide as an oxidizing agent A solution obtained by dissolving 18.7 g in xylene 100 ml was dropped from the dropping funnel, and then the temperature was 150 ° C.
For 1 hour. Then, after xylene was distilled off by an aspirator and a vacuum pump, the reaction product was taken out and cooled to room temperature to obtain a copolymer A.

<Copolymer B> Crystalline polyester 1 225 g (15 parts) Amorphous vinyl polymer 2 1275 g (85 parts) Copolymer B was obtained in the same manner as copolymer A using the above materials.

<Copolymer C> Crystalline polyester 1 225 g (15 parts) Amorphous vinyl polymer 3 1275 g (85 parts) Copolymer C was obtained in the same manner as copolymer A using the above materials.

<Copolymer D> Crystalline polyester 2 225 g (15 parts) Amorphous vinyl polymer 1 1275 g (85 parts) Copolymer D was obtained in the same manner as copolymer A using the above materials.

<Copolymer E> A copolymer E was obtained in the same manner as in the production of the copolymer A except that the amount of the xylene solution in which the condensing agent was dissolved was reduced by half.

<Copolymer a> Crystalline polyester 3 375 g (25 parts) Amorphous vinyl polymer 3 1125 g (75 parts) Using the above materials, a xylene solution in which a condensing agent was dissolved, and triphenylphosphine 20.4 g as a reducing agent A copolymer a for comparison was obtained in the same manner as the copolymer A except that a solution of 37.4 g of a condensing agent comprising 17.0 g of 2,2'-dipyridyl disulfide as an oxidizing agent was dissolved in 100 ml of xylene.

<Copolymer b> A copolymer b for comparison was obtained in the same manner as in the production of the copolymer B except that the xylene solution in which the condensing agent was dissolved was changed to 0.05 parts of p-toluenesulfonic acid.

<Copolymer c> A copolymer c for comparison was obtained in the same manner as in the production of the copolymer C, except that the xylene solution in which the condensing agent was dissolved was changed to 0.05 parts of p-toluenesulfonic acid.

<Copolymer d> Crystalline polyester 2 225 g (15 parts) Amorphous vinyl polymer 4 1275 g (85 parts) Using the above materials, the xylene solution in which the condensing agent was dissolved was changed to hexamethylene diisocyanate 2 parts. A copolymer d for comparison was obtained in the same manner as the copolymer A except for the above.

<Example 1> 100 parts of copolymer A 10 parts of carbon black 3 parts of paraffin wax 3 parts of alkylenebisfatty acid amide 3 parts of the above materials were put into a V-type mixer, mixed for 20 minutes, and melt-kneaded by a twin-screw extruder. After cooling, coarsely pulverized by a wheelie mill to obtain a 2 mm mesh pass product, further pulverized by a supersonic jet mill, and then fine particles having a particle diameter of 5 μm or less are removed by an air classifier to obtain colored particles having an average particle diameter of 11 μm. Was.

To 100 parts of the colored particles, 0.8 part of silica and 0.05 part of zinc stearate were mixed by a V-type mixer to produce Toner 1 of the present invention.

<Examples 2 to 5> In Example 1, copolymer A was replaced with copolymers B, C, D, and E.
The toners 2 to 5 of the present invention were produced in the same manner except that the above was changed.

<Comparative Examples 1-4> In Example 1, copolymer A was replaced with copolymers a, b, c, and d.
Comparative toners 1 to 4 were manufactured in the same manner except that the toner was changed.

<Evaluation> The following items were evaluated for the toners obtained in the above Examples and Comparative Examples, and the results are shown in Table 1 below.

(Graft rate of binder resin)

^{By 1} H-NMR, the ratio between the main chain methylene signal intensity and the terminal methylene signal intensity of the crystalline polyester was measured, and the graft ratio in the graft copolymer was calculated from the degree of decrease before and after the graft reaction by the above-described formula (III). Calculated using

(Pulverizability during toner production)

The amount of supply required to obtain an average particle size of 10 μm during pulverization when finely pulverized by a jet mill “PJM-100” (manufactured by Nippon Pneumatic Industries, Ltd.) was measured and used as an index of pulverizability. When the discharge air pressure is 6.0 kg / cm ² and the supply amount is 15 g / min or more,
Less than ~ 15 g / min was marked as "x".

[Toner fluidity]

Taking advantage of the fact that the powder having a higher fluidity has a lower compression degree, each toner was loosely filled into a container having a diameter of 28 mm and a volume of 100 ml from above, and the weight was measured to determine the static bulk density of the toner. Evaluation, static bulk density 0.40g / ml or more `` ○ '', 0.40
Less than g / ml was marked as "x".

(Coagulation of toner)

Take 2 g of each toner in a sample tube, 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%, then separate it with a 48 mesh sieve, and aggregate remaining on the sieve Was measured.

[Low-temperature fixability of toner]

Each toner is mixed with a coated carrier in which a fluorinated alkyl methacrylate polymer is coated on a ferrite core material having an average particle size of 80 μm at a ratio of 2% by weight, and the content (toner concentration) of the two components is 5% by weight. A developer was prepared.

An electrophotographic copier "U-Bix 1550MR" equipped with a latent image carrier made of an organic photoconductive semiconductor, a developing device for a two-component developer, and a heating roller fixing device, so that the set temperature of the heating roller can be variably adjusted. (Konica Co., Ltd.) modified the heating roller at a linear velocity of 139 mm / sec, and kept the pressure roller at a temperature lower than the setting temperature of the heating roller. While stepwise changing the temperature within a range of 240 ° C., a real 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 ratio of the image at the end was measured with a microdensitometer, and the lowest set temperature (minimum fixing temperature) showing a residual ratio of 80% or more was determined. The heating roller fixing device has a surface layer of PFA (tetrafluoroethylene / perfluoroalkylvinyl ether 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 and does not have a release agent application mechanism such as silicone oil.

[Hot offset resistance of toner]

Except that the pressure roller was kept at a temperature close to the set temperature of the heating roller, a fixed toner image was formed in the same manner as in the above [Low-temperature fixability of toner]. The operation of sending to the heat roller fixing device at, and visually observing whether or not toner contamination occurs on this,
The measurement was performed at each set temperature of the heating roller, and the highest set temperature (offset allowable temperature) at which toner contamination did not occur was determined.

[Image quality under high-temperature and high-humidity environmental conditions (temperature: 33 ° C., relative humidity: 80%)] An electrophotographic copying machine “U-” equipped with the organic latent image carrier, a developing device for a two-component developer, and a heating roller fixing device. Bix 155M
R "(manufactured by Konica Corporation), a real machine test to form a copy image using each of the above developers under high-temperature and high-humidity environmental conditions (temperature: 33 ° C, relative humidity: 80%). The image quality of the obtained image was visually evaluated.

From Table 1, it can be seen that the toner containing a specific copolymer having a graft ratio in the range of 40 to 90% as a binder resin as in the present invention has pulverizability, fluidity, cohesiveness and low-temperature fixability at the time of production. It is evident that they are excellent in all respects, such as hot offset resistance and image quality under high temperature and high humidity environment conditions.

In contrast, in Comparative Example 1, since the graft ratio of the copolymer used as the binder resin exceeded 90%, the pulverizability, fluidity, cohesiveness, and image quality under high-temperature and high-humidity environmental conditions during the production of the toner were high. It is clear that the present invention is inferior to the present invention in terms of the above.

Further, in Comparative Examples 2 to 4, since the graft ratio of the copolymer used as the binder resin was less than 40%, pulverizability, fluidity, cohesiveness, and image quality under high-temperature and high-humidity environmental conditions at the time of manufacturing the toner It is clear that the present invention is inferior to the present invention in terms of the above.

〔The invention's effect〕

According to the binder resin for a toner of the present invention, since a specific copolymer having a block ratio or a graft ratio of 40 to 90% is used, sufficient low-temperature fixability and high fluidity can be imparted to the toner. The pulverizability during the production of the toner can be improved.

According to the method for producing a binder resin for a toner of the present invention, since a condensing agent comprising a reducing agent and an oxidizing agent is used, it is possible to efficiently produce a specific copolymer having a high block ratio or graft ratio. it can.

Further, according to the toner of the present invention, since the toner contains the above-mentioned specific binder resin for a toner, the toner has excellent fluidity, blocking resistance, low-temperature fixing property, and hot offset resistance. Good image quality can be reproduced even under the conditions.

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroyuki Takagaki 2970 Ishikawacho, Hachioji-shi, Tokyo Inside Konica Corporation (56) References JP-A-2-881 (JP, A) JP-A-2-91661 ( JP, A) JP-A-3-6572 (JP, A) JP-A-3-9370 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 9/087

Claims (4)

(57) [Claims] 1. A crystalline polyester and an amorphous vinyl polymer having a functional group forming a bond with the crystalline polyester and having a weight average molecular weight Mw and a number average molecular weight Mn having a ratio Mw / Mn of 3.5 or more. And a block copolymer or a graft copolymer obtained by chemically bonding the block copolymer or the graft copolymer, wherein the block ratio or the graft ratio indicating the bonding ratio in the copolymer is 40 to 90%. Binder resin. 2. An amorphous vinyl polymer having a crystalline polyester and a functional group capable of forming a bond with the crystalline polyester, and having a weight average molecular weight Mw and a number average molecular weight Mn having a ratio Mw / Mn of 3.5 or more. A binder resin for a toner, comprising a block copolymer or a graft copolymer obtained by chemically bonding a coalesced substance with a condensing agent comprising a reducing agent and an oxidizing agent. 3. An amorphous vinyl polymer having a functional group forming a bond with the crystalline polyester and having a weight average molecular weight Mw and a number average molecular weight Mn having a ratio Mw / Mn of 3.5 or more. A method for producing a binder resin for a toner, characterized by forming a block copolymer or a graft copolymer by chemically bonding a coalesced compound with a condensing agent comprising a reducing agent and an oxidizing agent. 4. A toner comprising the binder resin for a toner according to claim 1 or 2.